U.S. patent application number 10/537640 was filed with the patent office on 2007-03-22 for cover body mounting structure of resin container.
Invention is credited to Naomasa Kaneko, Junichi Koseki, Hideki Matsumoto, Shinya Murabayashi, Toshiaki Nakai, Kazuhiro Nakamura, Tadahisa Nakamura, Daisuke Sato, Shoji Sato, Yoshihiro Watanabe, Taiki Yanase, Yuji Yoshizawa.
Application Number | 20070062841 10/537640 |
Document ID | / |
Family ID | 32512646 |
Filed Date | 2007-03-22 |
United States Patent
Application |
20070062841 |
Kind Code |
A1 |
Nakamura; Kazuhiro ; et
al. |
March 22, 2007 |
Cover body mounting structure of resin container
Abstract
A portion of the plastic container T where an opening 7 is
provided has a flange portion 7a, and provided are a recess
provided annularly along a peripheral edge of the opening 7 at an
outside of the plastic container body 2, with an annular member
being embedded integrally in the recess, a cover 1 resting against
the flange portion to close the opening 7, a seal 14 provided
between the flange portion 7a and the cover 1 to prevent a leak,
and an annular retainer 9 fastened to the annular member 8 while
resting against an external surface of the cover 1. This allows the
opening 7 provided in the plastic container T and the cover 1 to be
fastened together firmly with excellent and stable hermetical
sealing performance.
Inventors: |
Nakamura; Kazuhiro;
(Shioya-gun, JP) ; Sato; Shoji; (Shioya-gun,
JP) ; Watanabe; Yoshihiro; (Shioya-gun, JP) ;
Yoshizawa; Yuji; (Shioya-gun, JP) ; Murabayashi;
Shinya; (Wako-shi, JP) ; Matsumoto; Hideki;
(Wako-shi, JP) ; Nakamura; Tadahisa; (Wako-shi,
JP) ; Kaneko; Naomasa; (Wako-shi, JP) ;
Koseki; Junichi; (Wako-shi, JP) ; Sato; Daisuke;
(Wako-shi, JP) ; Nakai; Toshiaki; (Wako-shi,
JP) ; Yanase; Taiki; (Wako-shi, JP) |
Correspondence
Address: |
HAMRE, SCHUMANN, MUELLER & LARSON, P.C.
P.O. BOX 2902
MINNEAPOLIS
MN
55402-0902
US
|
Family ID: |
32512646 |
Appl. No.: |
10/537640 |
Filed: |
December 5, 2003 |
PCT Filed: |
December 5, 2003 |
PCT NO: |
PCT/JP03/15599 |
371 Date: |
September 8, 2006 |
Current U.S.
Class: |
206/562 |
Current CPC
Class: |
B60K 2015/03447
20130101; B60K 15/03177 20130101; F02M 37/103 20130101 |
Class at
Publication: |
206/562 |
International
Class: |
B65D 1/34 20060101
B65D001/34 |
Foreign Application Data
Date |
Code |
Application Number |
Dec 6, 2002 |
JP |
2002-355459 |
Dec 6, 2002 |
JP |
2002-355462 |
Jan 9, 2003 |
JP |
2003-002888 |
May 23, 2003 |
JP |
2003-146032 |
Jun 25, 2003 |
JP |
2003-180860 |
Claims
1. A cover-mounting structure of a plastic container having a cover
for closing an opening provided in a plastic container body at
least part of which is made of a barrier material, wherein a
portion of the plastic container where the opening is provided has
a flange portion; the cover-mounting structure of the plastic
container comprising: a recess provided annularly along a
peripheral edge of the opening at an outside of the plastic
container body, with an annular member being embedded integrally in
the recess; the cover resting against the flange portion to close
the opening; a seal provided between the flange portion and the
cover to prevent a leak; and an annular retainer fastened to the
annular member while resting against an external surface of the
cover.
2. A cover-mounting structure of a plastic container according to
claim 1, wherein a plurality of bolts for fastening the retainer
are provided protrusively in the annular member.
3. A cover-mounting structure of a plastic container according to
claim 1, wherein a screw hole is provided vertically in the annular
member.
4. A cover-mounting structure of a plastic container according to
claim 1, wherein the annular member and the retainer are formed of
metal materials.
5. A cover-mounting structure of a plastic container according to
claim 1, wherein a thread is formed on an outer or inner
cylindrical surface of the annular member.
6. A cover-mounting structure of a plastic container according to
claim 1, comprising: an outer rib projecting upwardly from an outer
edge of a top surface of the flange portion; and an inner rib
projecting downwardly from an undersurface of an outer edge portion
of the cover toward the top surface of the flange portion, wherein
the seal is provided in a space defined between the outer rib and
the inner rib; and wherein the outer rib comes into contact with
the undersurface of the outer edge portion of the cover when the
cover is placed over the opening.
7. A cover-mounting structure of a plastic container according to
claim 1, comprising: an outer rib projecting upwardly from an outer
edge of a top surface of the flange portion; and a seal guide
shaped like a letter L in cross section so as to conform to a shape
of a corner at an inner edge of the top surface of the flange
portion, wherein the seal is provided in a space defined between
the outer rib and the seal guide.
8. A cover-mounting structure of a plastic container according to
claim 7, wherein the seal guide is of a soft resin having a fuel
barrier property against HDPE (high-density polyethylene) with
solubility parameter of 11 or greater, or of a soft EVOH (alcohol
copolymer).
9. A cover-mounting structure of a plastic container according to
claim 1, comprising a metal ring provided between an area of a top
surface of an outer edge portion of the cover under which area the
seal is placed and a surface of the retainer which presses the
cover, wherein the metal ring has a spring tension acting in such a
direction that the portion of the plastic container where the
opening is provided is pressed by the cover.
10. A cover-mounting structure of a plastic container according to
claim 1, wherein the retainer has a spring tension acting in such a
direction that the portion where the opening is provided is pressed
by the cover.
11. A cover-mounting structure of a plastic container according to
claim 9, wherein pump fittings are integrally mounted in the
cover.
12. A cover-mounting structure of a plastic container according to
claim 4, wherein in the plastic container body immediately after
plastic molding, a space to be allowed for thermal contraction of
plastic is provided between an outer inside wall of the recess and
an outer cylindrical end face of the annular member.
13. A cover-mounting structure of a plastic container according to
claim 12, wherein the annular member is so shaped as to be kept
from obstructing the thermal contraction of the plastic container,
and includes a plurality of bolts provided protrusively at
annularly arranged positions along a peripheral edge of the
opening.
14. A cover-mounting structure of a plastic container according to
claim 12, wherein in the plastic container body thermally
contracted after plastic molding, the outer inside wall of the
recess and the outer cylindrical end face of at least one of the
annular member and the bolts are in contact with each other.
15. A cover-mounting structure of a plastic container according to
claim 12, wherein in the plastic container body after plastic
molding, a bottom surface of the space is in a position lower than
bottom surfaces of the annular member and the bolts.
16. A cover-mounting structure of a plastic container according to
claim 12, wherein in the plastic container body thermally
contracted after plastic molding, a drainage passage is provided in
an external surface of the plastic container body to drain water
that tends to stay in or around interfaces between the recess and
the annular member and between the recess and the bolts.
17. A cover-mounting structure of a plastic container according to
claim 12, wherein the annular member is insert-molded with a
plastic material from which the plastic container body is molded to
form the plastic container body.
18. A cover-mounting structure of a plastic container according to
claim 1, wherein a through hole is provided to allow a space formed
on a side of the retainer facing the plastic container body by
fastening the retainer to the annular member to communicate with
outside.
19. A cover-mounting structure of a plastic container according to
claim 18, wherein the through hole is provided in the retainer.
20. A cover-mounting structure of a plastic container according to
claim 18, wherein the through hole is provided between the annular
member and an external wall of the plastic container body to which
the annular member is fastened, or between the retainer and the
annular member.
Description
TECHNICAL FIELD
[0001] This invention relates to cover-mounting structures of a
plastic container such as an automotive fuel tank, which container
has an opening provided with a cover mounted to close the
opening.
BACKGROUND ART
[0002] The plastic container provided with an opening at one
surface and a cover for closing the opening is employed, for
example, as an automotive fuel tank or the like. An example of the
automotive fuel tank is schematically illustrated in perspective in
FIG. 23(a). A fuel tank 340, as shown in FIG. 23(a), includes a
cover 341 and a fitting port 342 to which a fuel feed pipe is
coupled. As shown in FIG. 23(b), which is a vertical section taken
along line S-S of FIG. 23(a), on top of a fuel tank body 343 is
provided an opening 345 to fit a pump module 344 therein, and the
opening 345 is closed with the cover 341. Integrally fixed on the
cover 341 are a fuel feed passage 346 for supplying an automotive
engine with fuel fed from the pump module 344, a fuel recirculation
passage 347 through which unconsumed fuel flows back from the
engine, and other components.
[0003] It has been known in the art to provide a plastic container
to be used as a fuel tank which has a holding ring structure for
fixing a cover over the opening of a tank body made of plastic. A
structure is disclosed in EP 0 816 151 A1, in which a groove for
receiving a seal is formed on a top surface of a flange portion
around the opening of the plastic tank body, so that the plastic
tank body and its cover are fastened together using a holding ring
made of metal with the seal being held in the groove.
[0004] FIG. 24 shows an opening of a fuel tank as embodied
according to a conventional example, in which FIG. 24(a) is a plan
view of the opening and FIG. 24(b) is a sectional view taken along
line V-V of FIG. 24(a).
[0005] As shown in FIGS. 24(a) and 24(b), a holding ring 420 made
of metal is fitted on a flange portion 412 defining an opening 414
of the fuel tank 410. The holding ring 420 is comprised of
segmental rings 420a and 420b, which are hinged on hooks 422 and
fastened together using a bolt 424 and a nut 425. These segmental
rings 420a, 420b clamp a holding plate 416 as a cover of a fuel
tank 410 to the flange portion 412, thereby hermetically closing
the fuel tank 410.
[0006] Another structure is disclosed in JP 2002-187162 A in which
on top of a plastic body of a tank is fitted an upper plate or the
like made of metal through which filler tubes and the like are led
out of the tank, and a camlock member made of metal that has been
insert-molded in the plastic body of the tank is provided for
fixing the upper plate.
[0007] A metal upper plate (not shown) or the like through which
filler tubes (not shown) and the like are led out is fitted on top
of a plastic tank body 501a that, as shown in FIG. 25, constitutes
a part of a fuel tank 501 having an insert-molded structure. This
tank body 501a is injection-molded using a high-density
polyethylene (HDPE) as raw materials, with a metal camlock member
504 for fixing the upper plate on a top surface of the tank body
501a being insert-molded therein. This camlock member 504 has a leg
portion 504a to be embedded in a wall of the tank body 501a and a
coating layer 505 is formed on peripheries of the leg portion 504a
by applying powder resin coating thereto beforehand. The camlock
member 504 is so placed as to allow this leg portion 504a to be
embedded in a peripheral edge of a plate opening 501b by an insert
molding process which opening is formed in the tank body 501a. On
the leg portion 504a of the camlock member 504, a thermoplastic
polyethylene resin material of the same kind as used to mold the
tank body 501a is applied to powder coat the surface thereof. The
polyethylene resin material has a high fusibility, and thus, once
applied, spreads substantially equally over the surface of the leg
portion 504a. Moreover, the camlock member 504 is heat-treated or
baked at a high temperature during the powder coating process, so
that powder of polyethylene resin material is baked and adhered
strongly to the surface of the leg portion 504a. Insert molding
process is then performed so that the leg portion 504a is embedded
in the tank body 501a. Thus baked and strongly adhered polyethylene
resin powder serves to enhance the adhesion between the tank body
501a and the camlock member 504 that have been combined together by
the action of resin materials fused with each other.
[0008] As shown in FIG. 26, a seal groove 630 is provided in a
flange portion 612 defining the opening of the fuel tank 610 at an
upper surface thereof; a seal 634 that is shaped like a ring and
substantially circular in section are fitted in the seal groove
630. A holding plate 616, provided as a cover for the fuel tank
610, presses the seal 634 and comes into contact with ribs 612a,
612b. This allows the holding plate 616 to hermetically close the
opening of the fuel tank 610.
[0009] In a conventional plastic fuel tank, a fuel pump having a
portion to be inserted into the fuel tank is mounted on a mount
plate, and fixed to the fuel tank. The fuel tank thus has an
opening for fitting the mount plate therein, and the mount plate
fitted in the opening has a sealing structure for liquid-tightly
closing the fuel tank. To that end, a structure known in the art
provides a threaded portion integrally formed at the opening of a
plastic fuel tank and a plastic cap member to be screwed onto the
threaded portion with a mount plate of the fuel pump held between
the cap member and the plastic fuel tank, thereby fixing the fuel
pump to the fuel tank. One example of this structure is disclosed
in JP 2002-80054 A.
[0010] FIG. 27 shows a part fixing portion serving to seal the
opening of the plastic fuel tank. As shown in FIG. 27, the part
fixing portion is formed, integrally with a plastic tank body 781
that has been blow-molded or otherwise formed, at a wall of the
tank body 781, and so configured as to project outwardly from a
peripheral edge of an opening 782 thereof; a cover plate (mount
plate) 785, which a part (not shown) has been mounted on and become
integral with, is held between a cylindrical threaded portion 783
formed integrally with the tank body 781 and a lock nut (nut
member) 784, and an internal thread cut on an inner cylindrical
surface of the lock nut 784 is screwed on an external thread cut on
an outer cylindrical surface of the cylindrical threaded portion
783, so that the part mounted in the cover plate 785 is fixed to
the tank body 781.
[0011] The part fixing portion has a sealing structure in which an
annular seal 786 is fitted around the periphery of a reducer
portion 788, which is provided at an edge of the cylindrical
threaded portion 783 with a radial portion 787 lying therebetween,
so that screwing the lock nut 784 on allows the seal 786 to be
pinched between a seal surface 787a extending radially on an upper
side of the radial portion 787 and a seal surface 785a formed
opposite thereto on an under side of the cover plate 785, thereby
exerting its sealing capability. Around the periphery of the seal
786 is provided a substantially vertically curved cylindrical
surface 784a formed on the inner cylindrical surface of the lock
nut 784 near the seal 786 as a restrictive means for restricting
the expanded seal 786 from protruding in radially outward
directions. The cylindrical surface 784a serves to restrict the
outward protrusion of the seal 786. Therefore, the outward
protrusion beyond a position at which the cylindrical surface 784a
places a restriction on the seal 786 that is likely to expand as a
result of absorption of fuel components. This makes the seal 786
kept from shifting away from the positions at which it is adhered
to the seal surfaces 785a, 787a and from changing considerably in
cross-sectional shape, thereby serving to prevent diminishment in
sealing properties.
[0012] The applicant of the present application has filed Japanese
Patent Application No. 2002-355459 entitled "Cover-Mounting
Structure of Fuel Tank".
[0013] FIG. 28 is a sectional view of a portion around an opening
of a fuel tank T according to the invention (directed to a
cover-mounting structure of a fuel tank) disclosed in the above
Japanese Application No. 2002-355459. As shown in FIG. 28, an
annular member 858 made of metal is insert-molded in a tank body
852 made of plastic. Bolts 861 that are embedded integrally in the
annular member 858 made of metal are also made of metal, and a
retainer 859 made of metal is fastened to the annular member 858
using the bolts 861 together with nuts 863. This makes it possible
to bring a portion 857 around the opening of the tank body 852 made
of plastic and a cover 851 into good and close contact with each
other, and firmly fix them together. Consequently, at the portion
857 around the opening provided in the tank body 852 of the fuel
tank T, the cover 851 can be hermetically attached to the portion
857 around the opening.
[0014] In the field of art directed to cover-mounting structures of
a plastic container such as an automotive fuel tank, it has been
generally known to provide a mounting part for fixing a cover over
an opening of a plastic container body, and a supporting part for
fixing the mounting part. For example, a structure as shown in FIG.
29, which is an enlarged view of portion D of FIG. 23(b), is
disclosed in JP 2003-72824 A.
[0015] As shown in FIG. 29, an annular seal 948 is provided between
a fuel tank body 943 and a cover 941, and the seal 948 includes a
fuel leakage prevention portion 948a provided in its inner region
and a water-tight portion provided in its outer region. The cover
941 is mounted on the fuel tank body 943 by fastening an outer
region 949b of a mounting part 949 to a supporting part 951 with a
bolt 950 having a flange portion 950a while pressing the cover 941
from outside with an inner region 949a of the mounting part
949.
[0016] For a plastic container having the aforementioned
cover-mounting structure, for example in a case where it is
particularly used for an automotive fuel tank, a submergence leak
test as shown in FIG. 30 may be performed in order to assess a
sealing performance. In this leak test, first, a fuel feed passage
946 and a fuel recirculation passage 947 are plugged with blanking
jigs 953, 953, and a pressurizing spigot jig 954 is provided in a
socket 942; further, the pressurizing spigot jig 954 and a pressure
regulator 955 are connected together by a pipe 956, and thereafter
a fuel tank 940 is submerged into a water tank 957 filled with
water. Subsequently, air of which pressure is regulated by the
pressure regulator 955 is flowed in a direction indicated by arrow
W, and air is thus introduced into the fuel tank body 943, so that
pressure within the fuel tank body 943 is increased to a
predetermined level.
[0017] If the fuel tank 940 has a leak, bubbles formed at a spot
where the leak would occur rise and swell in the water; thus,
visual observations, made from a direction indicated by arrow Y, of
the bubbles show whether the fuel tank 940 has a leak at any
spot.
[0018] Among the aforementioned conventional examples, however, the
structure which is configured to have a holding ring divided into
two segments which are in turn fastened together using a bolt/nut
pair so as to clamp a cover disadvantageously could not exercise
sufficient fastening strength.
[0019] In addition, such a divided holding ring could hardly form a
perfect circle, and thus segmentally contact the outer surface of
the wall defining the opening of the tank body, which would
disadvantageously make its sealing performance insecure.
[0020] The structure which is configured to have a holding ring
(camlock member) embedded in the external surface of the wall of
the tank body made of plastic by an insert molding process would
sever a barrier layer of the plastic tank body, which would
undesirably affect a layer structure thereof.
[0021] Further, among the aforementioned conventional examples is a
structure in which a surface for seal installation is provided near
the opening of the tank body made of plastic, a groove is formed in
the surface for seal installation, and a seal is placed in the
groove. The problems encountered in this structure are: it would be
difficult to ensure dimensional accuracy of the height of the upper
surface on either side of the groove which height is measured when
the upper surface comes into contact with the holding plate, and
particularly to control the dimensional accuracy in a blow molding
process; it would be difficult to finish a bottom surface of the
groove to the highest standard in surface roughness, with the
result that good sealing performance could not be achieved.
[0022] On the other hand, the structure in which the fuel tank is
made of plastic, and a tank body thereof and a cover plate (mount
plate) as a cap member are made of plastic would undergo
deterioration effects of time on plastic material,
disadvantageously lowering the accuracy and strength of a portion
where the part fixing portion is mounted.
[0023] Since still another of the aforementioned conventional
examples in which the tank body is made of plastic would allow the
tank body to shrink by heat with the passage of time,
disadvantageously, the accuracy of a joint portion where the
annular member and the tank body (plastic container) are joined
together could hardly be improved.
[0024] Furthermore, the cover-mounting structure as shown in FIG.
28 is configured to have the mounting part 49 fastened to the
supporting part 51, with the result that an enclosed hollow space
52 is provided, and thus bubbles which would be derived from air in
the enclosed hollow space 52 could possibly be identified
erroneously as the bubbles generated from inside of the fuel tank
body 43.
[0025] In order to avoid such an erroneous identification, at a
stage after the fuel tank 40 is submerged in the water tank 57 and
before pressure-regulated air is introduced therein, you should
wait until the enclosed hollow space 52 becomes filled with water
flown through very small gaps, for example, a gap 58 between the
mounting part 49 and the cover 41, which necessarily results in an
extended period of time for completion of the test. Moreover, even
in this instance, if air in the enclosed hollow space 52 could not
have been removed, bubbles derived from the air remaining in the
enclosed hollow space 52 could possibly appear during the test;
therefore, erroneous identification could not be avoided in any
event.
[0026] The present invention was made to solve the above-described
problems, and is directed to provide a cover-mounting structure of
a plastic container in which the layer structure of a barrier layer
provided in the plastic container is not affected, a high fastening
strength is exercised between an opening provided in the plastic
container and a cover, a good and secure sealing performance can be
achieved, the accuracy and strength of a portion where a cover and
a tank body are joined together will not lower with the passage of
time, an annular member can be mounted with improved accuracy, and
a submergence leak test can be performed easily with excellent
accuracy within a shortened period of time.
DISCLOSURE OF INVENTION
[0027] A cover-mounting structure of a plastic container according
to the present invention is a cover-mounting structure of a plastic
container having a cover for closing an opening provided in a
plastic container body at least part of which is made of a barrier
material, wherein a portion of the plastic container where the
opening is provided has a flange portion; the cover-mounting
structure of the plastic container comprising: a recess provided
annularly along a peripheral edge of the opening at an outside of
the plastic container body, with an annular member being embedded
integrally in the recess; the cover resting against the flange
portion to close the opening; a seal provided between the flange
portion and the cover to prevent a leak; and an annular retainer
fastened to the annular member while resting against an external
surface of the cover.
[0028] In this cover-mounting structure of a plastic container
having a construction as described above, a seamless annular member
is embedded in a portion around an opening of a tank body made of
plastic to form an integral part thereof, and thus the strength of
fastening between the plastic tank body and the cover can be
improved.
[0029] Further, an annular member assumes an undivided ring-shaped
geometry with no local rigidity variation point that would be
involved at seams of a ring-shaped geometry, and thus good
hermetical sealing performance between the tank body and the cover
can be stably achieved.
[0030] Further, an annular member is not cut into an external wall
of the tank body made of plastic so as not to sever a barrier layer
of the plastic tank body, and thus the possibility of affecting a
layer structure thereof can be eliminated.
[0031] The cover-mounting structure of a plastic container
according to the present invention may be characterized in that a
plurality of bolts for fastening the retainer are provided
protrusively in the annular member.
[0032] In this cover-mounting structure of a plastic container
having a construction as described above, insert bolts are provided
protrusively in an annular member, and with nuts screwed on the
bolts, a retainer can be firmly fastened; thus, the strength of
fastening between the plastic tank body and the cover can be
improved.
[0033] The cover-mounting structure of a plastic container
according to the present invention may be characterized in that a
screw hole is provided vertically in the annular member.
[0034] In this cover-mounting structure of a plastic container, a
screw hole is provided vertically in an annular member, and with a
bolt screwed into the screw hole, a retainer can be firmly
fastened; thus, the strength of fastening between the plastic tank
body and the cover can be improved.
[0035] The cover-mounting structure of a plastic container
according to the present invention may be characterized in that the
annular member and the retainer are formed of metal materials.
[0036] In this cover-mounting structure of a plastic container
having a construction as described above, an annular member and a
retainer for fixing the annular member are formed of metal
materials, and thus the retainer can be firmly fastened, so that
the strength of fastening between the plastic tank body and the
cover can be improved.
[0037] The cover-mounting structure of a plastic container
according to the present invention may be characterized in that a
thread is formed on an outer or inner cylindrical surface of the
annular member.
[0038] In this cover-mounting structure of a plastic container
having a construction as described above, a thread is formed on an
outer or inner cylindrical surface of an annular member, and thus
the annular member can be fastened firmly to a retainer, so that
the strength of fastening between the plastic tank body and the
cover can be improved.
[0039] The cover-mounting structure of a plastic container
according to the present invention may comprise: an outer rib
projecting upwardly from an outer edge of a top surface of the
flange portion; and an inner rib projecting downwardly from an
undersurface of an outer edge portion of the cover toward the top
surface of the flange portion, wherein the seal is provided in a
space defined between the outer rib and the inner rib; and wherein
the outer rib comes into contact with the undersurface of the outer
edge portion of the cover when the cover is placed over the
opening.
[0040] In this cover-mounting structure of a plastic container
having a construction as described above, an outer rib comes into
contact with a cover prior to an inner rib, which lightly touches
or does not touch a flange portion, and thus the outer rib can be
brought into secure and close contact with the cover; further, a
space for providing a seal can be made between the outer rib and
the inner rib, and thus excellent hermetical sealing performance
can be achieved. Moreover, an inner rib does not strongly press a
surface where a seal is placed, and thus deformation of the surface
where the seal is placed can be prevented so that good hermetical
sealing performance can be achieved.
[0041] The cover-mounting structure of a plastic container
according to the present invention may comprise: an outer rib
projecting upwardly from an outer edge of a top surface of the
flange portion; and a seal guide shaped like a letter L in cross
section so as to conform to a shape of a corner at an inner edge of
the top surface of the flange portion, wherein the seal is provided
in a space defined between the outer rib and the seal guide.
[0042] In this cover-mounting structure of a plastic container
having a construction as described above, a space is defined
between an outer rib projecting upwardly from an outer edge of a
top surface of flange portion, and a seal guide shaped like a
letter L in cross section so as to conform to a shape of a corner
at an inner edge of the top surface of the flange portion, and
further a space where a seal is placed can be made between the
outer rib and the seal guide; therefore, the outer rib can come
into secure and close contact with the cover, so that good
hermetical sealing performance can be achieved.
[0043] The cover-mounting structure of a plastic container
according to the present invention may comprise: an outer rib
projecting upwardly from an outer edge of a top surface of the
flange portion; and a seal guide shaped like a letter L in cross
section so as to conform to a shape of a corner at an inner edge of
the top surface of the flange portion, wherein the seal is provided
in a space defined between the outer rib and the seal guide, and
wherein the seal guide is of a soft resin having a fuel barrier
property against HDPE (high-density polyethylene) with solubility
parameter of 11 or greater, or of a soft EVOH (alcohol
copolymer).
[0044] In this cover-mounting structure of a plastic container
having a construction as described above, the seal guide is of a
soft resin having a fuel barrier property against HDPE
(high-density polyethylene) with solubility parameter of 11 or
greater, or of a soft EVOH (alcohol copolymer), and thus has an
excellent flexibility and an excellent barrier property, so that a
good hermetical sealing performance and an inhibitive effect of
preventing HC (hydrocarbon) from being transmitted can be achieved
as a sub-seal.
[0045] The cover-mounting structure of a plastic container
according to the present invention may comprise a metal ring
provided between an area of a top surface of an outer edge portion
of the cover under which area the seal is placed and a surface of
the retainer which presses the cover, wherein the metal ring has a
spring tension acting in such a direction that the portion of the
plastic container where the opening is provided is pressed by the
cover.
[0046] In this cover-mounting structure of a plastic container
having a construction as described above, a metal ring has a spring
tension acting in such a direction that the portion of the plastic
container where the opening is provided is pressed by the cover,
and the spring tension serves to make up for the change in
positioning and strength between the joined portions of the cover
and a portion around the opening, and can thereby maintain a
predetermined level of the positioning accuracy and adequate
strength; therefore, the change caused by the time-varying plastic
materials in positioning and strength between the joined portions
of the cover (mount plate) and the tank body can be prevented from
lowering.
[0047] The cover-mounting structure of a plastic container
according to the present invention may be characterized in that the
retainer has a spring tension acting in such a direction that the
portion where the opening is provided is pressed by the cover.
[0048] In this cover-mounting structure of a plastic container
having a construction as described above, a retainer has a spring
tension acting in such a direction that a portion where an opening
is provided is pressed by a cover, and the spring tension serves to
make up for the change in positioning and strength between the
joined portions of the cover and a portion around the opening, and
can thereby maintain a predetermined level of the positioning
accuracy and adequate strength; therefore, the change caused by the
time-varying plastic materials in positioning and strength between
the joined portions of the cover (mount plate) and the tank body
can be prevented from lowering.
[0049] The cover-mounting structure of a plastic container
according to the present invention may comprise a metal ring
provided between an area of a top surface of an outer edge portion
of the cover under which area the seal is placed and a surface of
the retainer which presses the cover, wherein the metal ring has a
spring tension acting in such a direction that the portion of the
plastic container where the opening is provided is pressed by the
cover, wherein pump fittings are integrally mounted in the
cover.
[0050] In this cover-mounting structure of a plastic container
having a construction as described above, pump fittings are
integrally mounted in the cover, and thus no clearance remains
between the pump fittings and the cover; therefore, the hermetical
sealing performance between the cover (mount plate) and the tank
body can be improved.
[0051] The cover-mounting structure of a plastic container
according to the present invention may be characterized in that the
annular member and the retainer are formed of metal materials, and
in the plastic container body immediately after plastic molding, a
space to be allowed for thermal contraction of plastic is provided
between an outer inside wall of the recess and an outer cylindrical
end face of the annular member.
[0052] In this cover-mounting structure of a plastic container
having a construction as described above, a space to be allowed for
thermal contraction of plastic is provided between an outer inside
wall of an annularly arranged recess and an outer cylindrical end
face of the annular member, and thus when the thermal contraction
is completed after plastic molding, the outer cylindrical end face
of the annular member and outer inside wall of the annular recess
come into contact with each other. This allows the annular member
and the plastic container body to be firmly joined together,
serving to maintain a good hermetical sealing performance of the
opening, as well as to improve positioning accuracy of the annular
member.
[0053] The cover-mounting structure of a plastic container
according to the present invention may be characterized in that the
annular member and the retainer are formed of metal materials, and
in the plastic container body immediately after plastic molding, a
space to be allowed for thermal contraction of plastic is provided
between an outer inside wall of the recess and an outer cylindrical
end face of the annular member, wherein the annular member is so
shaped as to be kept from obstructing the thermal contraction of
the plastic container, and includes a plurality of bolts provided
protrusively at annularly arranged positions along a peripheral
edge of the opening.
[0054] In this cover-mounting structure of a plastic container
having a construction as described above, the metal annular member
is so shaped as to be kept from obstructing the thermal contraction
of the plastic container, and thus bending or deformation due to
local internal shrinkage of thermally contracting plastic materials
can be prevented, so that the metal annular member can be slid
smoothly in the recess. Further, the metal annular member includes
a plurality of bolts provided protrusively at annularly arranged
positions along a peripheral edge of the opening, and thus a good
hermetical sealing performance of the opening can be maintained,
and positioning accuracy of the annular member can be improved.
[0055] The cover-mounting structure of a plastic container
according to the present invention may be characterized in that the
annular member and the retainer are formed of metal materials, and
in the plastic container body immediately after plastic molding, a
space to be allowed for thermal contraction of plastic is provided
between an outer inside wall of the recess and an outer cylindrical
end face of the annular member, and in the plastic container body
thermally contracted after plastic molding, the outer inside wall
of the recess and the outer cylindrical end face of at least one of
the annular member and the bolts are in contact with each
other.
[0056] In this cover-mounting structure of a plastic container
having a construction as described above, the outer inside wall of
the recess and the outer cylindrical end face of at least one of
the annular member and the bolts are in contact with each other,
and thus no clearance remains between the annular member and the
outer inside wall of the recess, which allows the annular member
and the plastic container body to be firmly joined together,
serving to maintain a good hermetical sealing performance of the
opening, as well as to improve positioning accuracy of the annular
member.
[0057] The cover-mounting structure of a plastic container
according to the present invention may be characterized in that the
annular member and the retainer are formed of metal materials,
wherein in the plastic container body immediately after plastic
molding, a space to be allowed for thermal contraction of plastic
is provided between an outer inside wall of the recess and an outer
cylindrical end face of the annular member, and wherein in the
plastic container body after plastic molding, a bottom surface of
the space is in a position lower than bottom surfaces of the
annular member and the bolts.
[0058] In this cover-mounting structure of a plastic container
having a construction as described above, the bottom surface of the
space formed in the recess is in a position lower than bottom
surfaces of the annular member and the bolts, and thus the outer
cylindrical end faces of the bolts can be brought into close
contact with the inside wall of the recess, which serves to
maintain a good hermetical sealing performance of the opening, as
well as to improve positioning accuracy of the annular member and
the plastic container body.
[0059] The cover-mounting structure of a plastic container
according to the present invention may be characterized in that the
annular member and the retainer are formed of metal materials,
wherein in the plastic container body immediately after plastic
molding, a space to be allowed for thermal contraction of plastic
is provided between an outer inside wall of the recess and an outer
cylindrical end face of the annular member, and wherein in the
plastic container body thermally contracted after plastic molding,
a drainage passage is provided in an external surface of the
plastic container body to drain water that tends to stay in or
around interfaces between the recess and the annular member and
between the recess and the bolts.
[0060] In this cover-mounting structure of a plastic container
having a construction as described above, a drainage passage is
provided in an external surface of the plastic container body to
drain water that tends to stay in or around interfaces between the
recess and the annular member and between the recess and the bolts,
and thus the interfaces between the bottom surfaces of the annular
recess and the annular member and spaces around the interfaces are
allowed to communicate by means of the drainage passage, which
allows water to drain to the outside, so as to prevent the
formation of rust, serving to maintain a good hermetical sealing
performance of the opening, as well as to improve positioning
accuracy of the annular member and the plastic container body.
[0061] The cover-mounting structure of a plastic container
according to the present invention may be characterized in that the
annular member and the retainer are formed of metal materials,
wherein in the plastic container body immediately after plastic
molding, a space to be allowed for thermal contraction of plastic
is provided between an outer inside wall of the recess and an outer
cylindrical end face of the annular member, and wherein the annular
member is insert-molded with a plastic material from which the
plastic container body is molded to form the plastic container
body.
[0062] In this cover-mounting structure of a plastic container
having a construction as described above, the annular member is
insert-molded with a plastic material from which the plastic
container body is molded to form the plastic container body, and
thus the annular member and the plastic container body can be
mounted with improved accuracy, which provides effective
countermeasures when collision or the like occurs.
[0063] The cover-mounting structure of a plastic container
according to the present invention may be characterized in that a
through hole is provided to allow a space formed on a side of the
retainer facing the plastic container body by fastening the
retainer to the annular member to communicate with outside.
[0064] In this cover-mounting structure of a plastic container
having a construction as described above, when the plastic
container is submerged into a water tank during a submergence leak
test, water is allowed to flow through the through hole to fill up
the space for a short period of time. Accordingly, no extra time to
wait is required from submergence of the plastic container into the
water tank to introduction of pressure-regulated air, and therefore
the time for testing can be reduced. Moreover, the evolution of
bubbles derived from air in the space during the test can be
prevented so as not to make an erroneous identification as
described above. Consequently, the submergence leak test can be
performed with improved accuracy.
[0065] The cover-mounting structure of a plastic container
according to the present invention may be characterized in that a
through hole to allow a space formed on a side of the retainer
facing the plastic container body by fastening the retainer to the
annular member to communicate with outside is provided in the
retainer.
[0066] In this cover-mounting structure of a plastic container
having a construction as described above, the through hole is
provided in the retainer, and assuming that the bottom of the
plastic container faces toward downward while the cover is located
on its top, the through hole allows the space to immediately
communicate at its top. Therefore, air that was in the space at the
time of submergence of the plastic container into the water tank is
discharged swiftly through the through hole by which the space
communicates at its top. As a result, in the submergence leak test,
the evolution of bubbles derived from air in the space during the
test can be prevented without fail, and the submergence leak test
can be performed with much more improved accuracy.
[0067] The cover-mounting structure of a plastic container
according to the present invention may be characterized in that a
through hole to allow a space formed on a side of the retainer
facing the plastic container body by fastening the retainer to the
annular member to communicate with outside is provided between the
annular member and an external wall of the plastic container body
to which the annular member is fastened, or between the retainer
and the annular member.
[0068] In this cover-mounting structure of a plastic container
having a construction as described above, the through hole is
provided which allows the space to immediately communicate at its
bottom, and thus when the plastic container is raised from the
water tank after the submergence leak test has been carried out,
water with which the space is filled can be discharged swiftly
through the through hole. Accordingly, the process for drying the
plastic container after the test can be performed with increased
ease, and corrosion of constituent parts, which would result from
residual water after the test, can be prevented.
[0069] Further, even if the plastic container is submerged into
water in normal times of use, water flowed into the space can be
drained through the through hole; thus corrosion of constituent
parts, which would otherwise result from submergence in normal
times of use, can also be prevented.
[0070] Further, in a case where another through hole which allows
the space to immediately communicate at its top is provided in
addition to the through hole which allows the space to immediately
communicate at its bottom, when water is discharged through the
through hole which allows the space to immediately communicate at
its bottom after a submergence leak test has been carried out, the
pressure of air flowed into the space pushes water in the space, so
that the water can be discharged more swiftly. Accordingly, a
process for drying the plastic container after the test can be
performed with further increased ease, and corrosion of constituent
parts, which would result from residual water after the test, can
be prevented more effectively. Furthermore, corrosion of
constituent parts, which would result from submergence in normal
times of use, can also be prevented with a high degree of
reliability.
BRIEF DESCRIPTION OF DRAWINGS
[0071] FIG. 1 schematically shows a cover-mounting structure of a
fuel tank according to a first embodiment of the present invention;
(a) is a perspective view, and (b) is a vertical sectional view
taken along line A-A of (a).
[0072] FIG. 2 shows: (a) an enlarged sectional view of portion B of
FIG. 1(a); and (b) an enlarged and exploded view of portion C of
(a).
[0073] FIG. 3 shows: (a) an enlarged sectional view of a
cover-mounting structure of a fuel tank according to a second
embodiment of the present invention; and (b) an enlarged sectional
view of a cover-mounting structure of a fuel tank according to a
third embodiment of the present invention.
[0074] FIG. 4 shows: (a) an enlarged sectional view of a
cover-mounting structure of a fuel tank according to a fourth
embodiment of the present invention; (b) an enlarged sectional view
of a cover-mounting structure of a fuel tank according to a fifth
embodiment of the present invention; and (c) an enlarged sectional
view of a cover-mounting structure of a fuel tank according to a
sixth embodiment of the present invention.
[0075] FIG. 5 shows: (a) an enlarged sectional view of a
cover-mounting structure of a fuel tank according to a seventh
embodiment of the present invention; and (b) an enlarged sectional
view of a cover-mounting structure of a fuel tank according to a
eighth embodiment of the present invention.
[0076] FIG. 6 schematically shows a cover-mounting structure of a
fuel tank according to a ninth embodiment of the present invention;
(a) is an enlarged sectional view of portion B of FIG. 1, and (b)
is an enlarged sectional view of portion D of (a).
[0077] FIG. 7 is an enlarged and exploded sectional view of FIG. 6
(b) for explaining relative positioning of an opening and a cover
included therein.
[0078] FIG. 8 is an enlarged sectional view of a modified example
of the arrangement shown in FIG. 6 (b), schematically showing a
cover-mounting structure of a fuel tank according to a tenth
embodiment of the present invention.
[0079] FIG. 9 is an enlarged sectional view of portion B of FIG. 1,
schematically showing a cover-mounting structure of a fuel tank
according to an eleventh embodiment of the present invention.
[0080] FIG. 10 is a detailed sectional view showing portion E of
FIG. 9.
[0081] FIG. 11 is a schematic illustration of a metal ring, in
which (a) is a plan view, and (b) is a vertical sectional view
taken along line F-F of (a).
[0082] FIG. 12 is an enlarged sectional view of portion B of FIG.
1, schematically showing a cover-mounting structure according to a
twelfth embodiment of the present invention.
[0083] FIG. 13 is a detailed view sectionally showing portion G of
FIG. 12.
[0084] FIG. 14 is a schematic illustration of a retainer, in which
(a) is a plan view, and (b) is a vertical sectional view taken
along line H-H of (a).
[0085] FIG. 15 is a perspective view schematically showing a fuel
tank according to a thirteenth embodiment of the present
invention.
[0086] FIG. 16 shows: (a) a vertical sectional view taken along
line I-I of FIG. 15; and (b) an illustration of portion J of (a) as
viewed from arrow B.
[0087] FIG. 17 is a vertical sectional view of portion Q of FIG.
16(a).
[0088] FIG. 18 represents enlarged sectional views showing portion
L of FIG. 17, in which (a) is a sectional view of a portion around
an opening immediately after plastic molding, and (b) is a
sectional view of the portion around the opening which has
completely been thermally contracted after plastic molding.
[0089] FIG. 19 is a sectional view taken along line K-K of FIG.
16(b).
[0090] FIG. 20 is an exploded perspective view of a cover-mounting
structure of a plastic container according to a fourteenth
embodiment of the present invention.
[0091] FIG. 21 is a diagram representing the cover-mounting
structure of which constitutional parts shown in FIG. 20 are
assembled together, in which (a) is a plan view, (b) is a vertical
sectional view taken along line N-N of (a), and (c) is a vertical
sectional view taken along line P-P of (a).
[0092] FIG. 22 shows several views of a cover-mounting structure of
a plastic container according to a fifteenth embodiment of the
present invention, in which (a) is a vertical sectional view of a
portion where a mounting part and a supporting part are fastened,
and (b) is a vertical sectional view of a through hole.
[0093] FIG. 23 schematically shows a plastic container having a
conventional cover-mounting structure; (a) is a general view in
perspective, and (b) is a vertical sectional view taken along line
S-S of (a).
[0094] FIG. 24 is a diagram schematically showing a conventional
holding ring of a cover of a fuel tank, in which (a) is a side view
in section, and (b) is a plan view thereof.
[0095] FIG. 25 is sectional view schematically showing an
insert-molded structure provided in a conventional plastic
tank.
[0096] FIG. 26 is a sectional view schematically showing a
conventional cover-mounting structure of a fuel tank.
[0097] FIG. 27 is a sectional view schematically showing a
conventional example of a cover-mounting portion, in which a
portion corresponding to portion E of FIG. 9 is depicted.
[0098] FIG. 28 is a sectional view schematically showing a
conventional cover-mounting structure of a fuel tank.
[0099] FIG. 29 is an enlarged view of portion U of FIG. 23(b).
[0100] FIG. 30 is a schematic diagram for illustrating a process of
performing a submergence leak test.
BEST MODES FOR CARRYING OUT THE INVENTION
[0101] A description will be given one by one of embodiments of a
cover-mounting structure of a fuel tank according to the present
invention with reference to the drawings.
First Embodiment
[0102] FIG. 1 schematically shows a fuel tank according to a first
embodiment; FIG. 1(a) is a perspective view of a cover-mounting
structure, and FIG. 1(b) is a vertical sectional view taken along
line A-A of FIG. 1(a). As shown in FIGS. 1(a) and 1(b), a fuel tank
T, at least part of which plastic tank body is of a barrier
material, includes a plastic tank body 2 for storing fuel and an
opening 7 provided in the tank body 2, whereas a cover 1 is mounted
over the opening 7. On the cover 1, integrally fixed thereto are a
fuel feed passage 4 for supplying an automotive engine with fuel
fed from a fuel pump 6 provided in the plastic tank body 2, a fuel
recirculation passage 5 through which unconsumed fuel flows back
from the engine, and other components. In the plastic tank body 2
is provided a fitting port 3 to which one end of a fuel feed pipe
is to be coupled while the other end thereof is to open on a
vehicle body of an automobile.
[0103] FIG. 2 schematically shows the cover 1 of the fuel tank
according to the first embodiment; FIG. 2(a) is an enlarged
sectional view of portion B of FIG. 1(b), and FIG. 2(b) is an
exploded sectional view of portion C of FIG. 2(a). As shown in FIG.
2(a), the cover 1 is mounted over the opening 7 provided in the
tank body 2 of the fuel tank T. At an edge of the opening 7 is
formed a flange portion 7a, and a seal 14 is placed annularly on a
top surface of the flange portion 7a, so that a leak between the
flange portion 7a and the cover 1 is prevented. Around the opening
7, an annular member 8 that is larger in diameter than the opening
7 and made of metal is embedded by an undersurface 7b of the flange
portion 7a, a recessed outside wall 7c provided around the opening
7, and a tank outside wall 2a.
[0104] The annular member 8 is provided in a manner that allows the
tank outside wall 2a to become recessed and tucked up around an
inner periphery of the annular member 8 so that the annular member
8 is held by the tank body 2. A separately provided retainer 9 made
of metal is formed in a manner that allows one end portion (inner
peripheral portion) of the retainer 9 to come into contact with an
outer edge portion 1a of the cover 1 serving to hermetically close
the opening 7 while the other end portion (outer peripheral
portion) of the retainer 9 is in contact with the annular member 8,
thereby fastening the cover 1 to the tank body 2. In the end
portion (outer peripheral portion) of the retainer 9 is provided a
retainer hole 9a through which a bolt 11 is to be inserted.
[0105] As shown in FIG. 2(b), according to the first embodiment,
the annular member 8 is joined integrally to an outside of a
peripheral edge portion of the opening 7 of the tank body 2 made of
plastic through an insert molding process in which the annular
member 8 made of metal is combined with the tank body 2 while the
tank body 2 made of plastic is being blow-molded. In the annular
member 8 are provided a plurality of bolts 11 (for example, eight
of the bolts are provided in the present embodiment), which are
substantially evenly spaced around its circumference and each
fitted in a hole 8a and held upright, e.g., upwardly protrusive as
shown in the drawing. Hereupon, the bolts 11 may be fixed to the
annular member 8 by means of press-fitting, welding or
screwing.
[0106] A description will now be given of the cover-mounting
structure of a fuel tank having the above construction in
operation. A shown in FIG. 2, the cover 1 is mounted on a portion
of the tank body 2 of the fuel tank T where the opening 7 is
provided, so as to hermetically close the opening 7. In the tank
body 2, the annular member 8 that is larger in diameter than the
opening 7 of the tank body 2 and made of metal is mounted
integrally by an insert molding process so that it is covered by
the tank body 2 made of plastic, and the bolts 11 are fitted in the
holes 8a and embedded in the annular member 8. The seal 14 is
provided annularly on the top surface of the flange portion 7a of
the round opening 7, and the round cover 1 is placed over the
opening 7 while the undersurface of the outer edge portion 1a of
the round cover 1 comes in contact with a top surface of the seal
14.
[0107] Since a predetermined number of bolts 11 are embedded in the
annular member 8 that is mounted along the outside wall provided
around the opening 7 so that the bolts 11 upwardly protrude
respectively from substantially evenly spaced positions, each bolt
11 is fitted in the retainer hole 9a provided in one end portion
(outer peripheral portion) of the retainer 9 and the other end
portion (inner peripheral portion) of the retainer 9 comes into
contact with the outer edge portion 1a provided at an outer edge of
the cover 1. Nuts 13 are then screwed on the bolts 11, so that the
cover 1 is fixed so as to hermetically close the opening 7.
[0108] As described above, the annular member 8 that is
insert-molded in the tank body 2 made of plastic is a metal member,
and the bolts 11 that are embedded integrally in this annular
member 8 made of metal are metal members as well; therefore, the
retainer 9 that is a metal member can be fastened with the nuts 13
so that the cover 1 can be fixed and kept in good and close contact
with a portion around the opening 7 of the plastic tank body 2.
Second Embodiment
[0109] FIG. 3(a) is an enlarged sectional view of a cover-mounting
structure of a fuel tank according to a second embodiment. The
second embodiment exemplifies a structure in which an annular
member 38 with bolts 31 fitted upwardly therein is integrally
insert-molded in a tank body 32 made of plastic.
[0110] In FIG. 3(a), the same elements as in FIG. 2(b) are
designated by the same reference numerals, and a description
thereof will be omitted.
[0111] As shown in FIG. 3(a), the annular member 38 with the bolts
31 inserted therethrough and projected upwardly therefrom is
integrally insert-molded in the tank body 32. The cover-mounting
structure according to the second embodiment is different, in that
the bolts 31 are fitted in the annular member 38, from the first
embodiment in which the bolts 11 are integrally formed in the
annular member 8 by welding or the like as shown in FIG. 2.
[0112] A description will now be given of the cover-mounting
structure of a fuel tank having the above construction in
operation. As shown in FIG. 3(a), a cover 1 is attached to a
portion of the tank body 32 made of plastic where an opening 37 is
provided in such a manner that the cover 1 hermetically closes the
opening 37. In the tank body 32, the annular member 38 that is
larger in diameter than the opening 37 of the tank body 32 and made
of metal is mounted integrally by an insert molding process so that
it is covered by the tank body 32 made of plastic. In the annular
member 38, in turn, are embedded the bolts 31. A seal 14 is
provided annularly on the top surface of a flange portion 37a
formed around the round opening 37, and the cover 1 is placed over
the opening 37 while the outer edge portion 1a of the round cover 1
comes in contact with the top surface of the seal 14.
[0113] Since a predetermined number of bolts 31 are upwardly
inserted and fitted in the annular member 38 that is mounted along
the outside wall provided around the opening 37, so that the bolts
31 protrude respectively from substantially evenly spaced
positions, each bolt 31 is fitted in the retainer hole 39a provided
in one end portion (outer peripheral portion) of the retainer 39
and the other end portion (inner peripheral portion) of the
retainer 39 comes into contact with the outer edge portion 1a
provided at the outer edge of the cover 1. Nuts 33 are then screwed
on the bolts 31, so that the cover 1 is fixed so as to hermetically
close the opening 37.
[0114] As described above, the annular member 38 that is
insert-molded in the tank body 32 made of plastic is a metal
member, and the bolts 31 that are inserted and fitted in this
annular member 38 made of metal are metal members as well;
therefore, the retainer 39 that is a metal member can be firmly
fastened with the nuts 33 so that the cover 1 can be fixed and kept
in good and close contact with a portion around the opening 37 of
the plastic tank body 32.
Third Embodiment
[0115] FIG. 3(b) is an enlarged sectional view of a cover-mounting
structure of a fuel tank according to a third embodiment. The third
embodiment exemplifies a structure in which bolts 41 are fitted in
an annular member 48 integrally insert-molded in a tank body 42
made of plastic.
[0116] In FIG. 3(b), the same elements as in FIG. 2(b) are
designated by the same reference numerals, and a description
thereof will be omitted.
[0117] As shown in FIG. 3(b), the annular member 48 is integrally
insert-molded in the tank body 42 made of plastic. The
cover-mounting structure according to the third embodiment is
different, in that the fitting of the bolts 41 into the annular
member 48 follows the insert molding of the annular member 48 in
the tank body 42, from the second embodiment in which the annular
member 38 having the bolts 31 fitted therein is insert-molded in
the tank body 32.
[0118] A description will now be given of the cover-mounting
structure of a fuel tank having the above construction in
operation.
[0119] As shown in FIG. 3(b), a cover 1 is attached to a portion of
the tank body 42 made of plastic where an opening 47 is provided in
such a manner that the cover 1 hermetically closes the opening 47.
In the tank body 42 made of plastic, the annular member 48 that is
larger in diameter than the opening 47 of the tank body 42 and made
of metal is mounted integrally by an insert molding process so that
it is covered by the tank body 42 made of plastic. In the annular
member 48, the bolts 41 are fitted upwardly. A seal 14 is provided
annularly on the top surface of a flange portion 47a formed around
the round opening 47, and the cover 1 is placed over the opening 47
while the outer edge portion 1a of the round cover 1 comes in
contact with the top surface of the seal 14.
[0120] A predetermined number of the bolts 41 are upwardly inserted
and fitted in the annular member 48 that is mounted along the
outside wall provided around the opening 47, so that the bolts 41
protrude respectively from substantially evenly spaced positions;
each bolt 41 is fitted in the retainer hole 49a provided in one end
portion (outer peripheral portion) of the retainer 49 and the other
end portion (inner peripheral portion) of the retainer 49 comes
into contact with the outer edge portion 1a provided at the outer
edge of the cover 1. Nuts 43 are then screwed on the bolts 41, so
that the cover 1 is fixed so as to hermetically close the opening
47.
[0121] As described above, the annular member 48 that is
insert-molded in the tank body 42 made of plastic is a metal
member, and the bolts 41 that are inserted and fitted in this
annular member 48 made of metal are metal members as well;
therefore, the retainer 49 that is a metal member can be firmly
fastened up with the nuts 43 so that the cover 1 can be fixed and
kept in good and close contact with a portion around the opening 47
of the plastic tank body 42.
Fourth Embodiment
[0122] FIG. 4(a) is an enlarged sectional view of a cover-mounting
structure of a fuel tank according to a fourth embodiment. The
fourth embodiment exemplifies a structure in which an annular
member 58 integrally insert-molded in a tank body 52 made of
plastic is provided with screw holes 58a.
[0123] In FIG. 4(a), the same elements as in FIG. 2(b) are
designated by the same reference numerals, and a description
thereof will be omitted.
[0124] As shown in FIG. 4(a), the annular member 58 having screw
holes 58a each provided in an orientation vertical to the annular
member 58 is integrally insert-molded in the tank body 52. The
cover-mounting structure according to the fourth embodiment is
different, in that the screw holes 58a are each provided vertically
in the annular member 58, from the first embodiment in which the
bolts 11 are integrally formed in the annular member 8 by welding
or the like. The screw holes 58a are provided at a plurality of
positions (for example, eight of which are provided in the fourth
embodiment) in the annular member 58 around its circumference, and
are each oriented upwardly as shown in the drawing.
[0125] A description will now be directed to the cover-mounting
structure of a fuel tank having the above construction in
operation. As shown in FIG. 4(a), a cover 1 is attached to a
portion of the tank body 52 where an opening 57 is provided in such
a manner that the cover 1 hermetically closes the opening 57. In
the tank body 52 made of plastic, the annular member 58 that is
larger in diameter than the opening 57 of the tank body 52 and made
of metal is mounted integrally by an insert molding process so that
it is covered by the tank body 52 made of plastic. In the annular
member 58, the screw holes 58a are provided. A seal 14 is provided
annularly on the top surface of a flange portion 57a formed around
the round opening 57, and the cover 1 is placed over the opening 57
while the outer edge portion 1a of the round cover 1 comes in
contact with the top surface of the seal 14.
[0126] In the annular member 58 that is mounted along the outside
wall provided around the opening 7 are provided the screw holes 58a
at predetermined positions that are substantially evenly spaced out
around the circumference of the annular member 58. Retainer holes
59a provided in one end portion (outer peripheral portion) of a
retainer 59 are aligned with these screw holes 58a and the other
end portion (inner peripheral portion) of the retainer 59 is
brought into contact with the outer edge portion 1a of the cover 1.
Thereafter, bolts 51 are screwed into the screw holes 58a, and the
cover 1 is thereby fixed so as to hermetically close the opening
57.
[0127] As described above, the annular member 58 that is
insert-molded in the tank body 52 made of plastic is a metal
member, and the screw holes 58a that are provided in the annular
member 58 made of metal are metal members as well; therefore, the
retainer 59 that is a metal member can be firmly fastened up with
the bolts 51 so that the cover 1 can be fixed and kept in good and
close contact with a portion around the opening 57 of the plastic
tank body 52.
Fifth Embodiment
[0128] FIG. 4(b) is an enlarged sectional view of a cover-mounting
structure of a fuel tank according to a fifth embodiment. The fifth
embodiment exemplifies a structure in which an annular member 68
integrally insert-molded in a tank body 62 made of plastic is
provided with screw holes 68a.
[0129] In FIG. 4(b), the same elements as in FIG. 2(b) are
designated by the same reference numerals, and a description
thereof will be omitted.
[0130] As shown in FIG. 4(b), the annular member 68 provided with
the screw holes 68a is integrally insert-molded in the tank body
62. The cover-mounting structure according to the fifth embodiment
represents a variation in which the retainer 59 in the fourth
embodiment is modified, and includes a retainer 69 which is a
ring-shaped circular plate having an opening in the center thereof.
The operation of the cover-mounting structure of a fuel tank having
the above construction is understood in a fashion analogous to the
fourth embodiment as shown in FIG. 4(a), and thus a duplicate
discussion thereof will not be given herein.
Sixth Embodiment
[0131] FIG. 4(c) is an enlarged sectional view of a cover-mounting
structure of a fuel tank according to a sixth embodiment. The sixth
embodiment exemplifies a structure in which an annular member 78
integrally insert-molded in a tank body 72 made of plastic is
provided with screw holes 78a.
[0132] In FIG. 4(c), the same elements as in FIG. 2(b) are
designated by the same reference numerals, and a description
thereof will be omitted. In FIG. 4(c), the annular member 78
provided with the screw holes 78a is integrally insert-molded in
the tank body 72. The cover-mounting structure according to the
sixth embodiment is different, in that the screw holes 78a are
provided in the annular member 78 and thus bolts 71 are inserted
respectively from upward through retainer holes 79a and screwed
down into the screw holes 78a, from the third embodiment. The
operation of the cover-mounting structure of a fuel tank having the
above construction is understood in a fashion analogous to the
fourth embodiment as shown in FIG. 4(a), and thus a duplicate
discussion thereof will not be given herein.
Seventh Embodiment
[0133] FIG. 5(a) is an enlarged sectional view of a cover-mounting
structure of a fuel tank according to a seventh embodiment. The
seventh embodiment exemplifies a structure in which an annular
member 88 integrally insert-molded in a tank body 82 made of
plastic is provided.
[0134] In FIG. 5(a), the same elements as in FIG. 2(b) are
designated by the same reference numerals, and a description
thereof will be omitted.
[0135] As shown in FIG. 5(a), the annular member 88 is bent and
formed into a substantially inverted T shape, and integrally
insert-molded in the tank body 82. In the cover-mounting structure
of a fuel tank according to the seventh embodiment, a retainer 89
is screwed on the annular member 88 so that an internal thread 89b
provided in a downwardly bent outer cylindrical portion 89a of the
retainer 89 engages in an external thread 88a provided in an outer
cylindrical surface of a vertical riser portion 88b of the annular
member 88.
[0136] A description will now be directed to the cover-mounting
structure of a fuel tank having the above construction in
operation. As shown in FIG. 5(a), a cover 1 is attached to a
portion of the tank body 82 where an opening 87 is provided in such
a manner that the cover 1 hermetically closes the opening 87. In
the tank body 82 made of plastic, the annular member 88 that is
larger in diameter than the opening 87 of the tank body 82 and made
of metal is mounted integrally by an insert molding process so that
it is covered by the tank body 82 made of plastic. A seal 14 is
provided annularly on the top surface of a flange portion 87a
formed around the round opening 87, and the round cover 1 is placed
over the opening 87 while the outer edge portion 1a of the cover 1
comes in contact with the top surface of the seal 14.
[0137] Since the internal thread 89b provided in the downwardly
bent outer cylindrical portion 89a of the retainer 89 engages in
the external thread 88a provided in the outer cylindrical surface
of the vertical riser portion 88b of the annular member 88 that is
mounted along the outside wall provided around the opening 87, the
cover 1 can be fixed so as to hermetically close the opening 87 by
screwing the retainer 89 on.
[0138] As described above, the annular member 88 that is
insert-molded in the tank body 82 made of plastic is a metal
member, and thus the retainer 89 that is a metal member is screwed
on, so that the cover 1 can be fixed and kept in good and close
contact with a portion around the opening 87 of the plastic tank
body 82.
Eighth Embodiment
[0139] FIG. 5(b) is an enlarged sectional view of a cover-mounting
structure of a fuel tank according to an eighth embodiment. The
eighth embodiment exemplifies a structure in which an annular
member 98 integrally insert-molded in a tank body 92 made of
plastic is provided with an internal thread 98a.
[0140] In FIG. 5(b), the same elements as in FIG. 2(b) are
designated by the same reference numerals, and a description
thereof will be omitted.
[0141] As shown in FIG. 5(b), the annular member 98 has the
internal thread 98a provided therein and is integrally
insert-molded in the tank body 92. In this cover-mounting structure
according to the eighth embodiment, the internal thread 98a is
provided in the annular member 98, and an external thread 99a is
provided in an outer cylindrical surface of an annular nut 99 as a
retainer.
[0142] A description will now be directed to the cover-mounting
structure of a fuel tank having the above construction in
operation. As shown in FIG. 5(b), a cover 1 is attached to a
portion of the tank body 92 where an opening 97 is provided in such
a manner that the cover 1 hermetically closes the opening 97. In
the tank body 92 made of plastic, the annular member 98 that is
larger in diameter than the opening 97 of the tank body 92 and made
of metal is mounted integrally by an insert molding process so that
it is covered by the tank body 92 made of plastic. The internal
thread 98a is provided in the annular member 98. A seal 14 is
provided annularly on the top surface of a flange portion 97a
formed around the round opening 97, and the cover 1 is placed over
the opening 97 while the outer edge portion 1a of the round cover 1
comes in contact with the top surface of the seal 14.
[0143] Since the internal thread 98a is provided in the annular
member 98 that is mounted along the outside wall provided around
the opening 97, this internal thread 98a engages in the external
thread 99a provided in one end portion (outer peripheral portion)
of the nut 99. Thereafter, the external thread 99a is engaged with
and screwed on the internal thread 98a, and the cover 1 is thereby
fixed so as to hermetically close the opening 97.
[0144] As described above, the annular member 98 that is
insert-molded in the tank body 92 made of plastic is a metal
member, and can thus be firmly fastened with the external thread
provided in the outer cylindrical surface of the nut 99 that is a
metal member. Accordingly, the cover 1 can be fixed and kept in
good and close contact with a portion around the opening 97 of the
plastic tank body 92. Hereupon, on a top surface of the nut 99,
recessed portions are provided, though not illustrated, in at least
two positions thereof, and the nut 99 can be fastened by using a
predetermined jig.
[0145] Although some preferred embodiments have been described
above, it is to be appreciated that the present invention is not
limited to the above-described embodiments, and modifications may
be made as appropriate which fall within the scope of the present
invention without departing the spirit thereof. For example, in the
aforementioned embodiments, a discussion is extended on the premise
that the retainer provided has an annular shape, but the retainer
is not necessarily annular, and may have the shape of a solid
piece.
Ninth Embodiment
[0146] FIG. 6 schematically shows a cover-mounting structure of a
fuel tank according to a ninth embodiment of the present invention;
FIG. 6(a) is an enlarged sectional view of portion B of FIG. 1, and
FIG. 6(b) is an enlarged sectional view of portion D of FIG. 6(a).
As shown in FIGS. 6(a) and 6(b), a cover 101 is mounted over an
opening 107 provided in a tank body 102 made of plastic. At an edge
of the opening 107 provided in the tank body 102 made of plastic is
formed a flange portion 107a, and an outer rib 107f is provided
annularly, which projects upwardly from an outer edge 107e of a top
surface of the flange portion 107a. An inner rib 101c is provided,
which projects downwardly from an undersurface of an outer edge
portion 101a of the cover 101 in a radially inside position nearer
to the center of the opening 107 than that of the outer rib 107f,
toward the top surface 107b of the flange portion 107a. To put it
shortly, the outer rib 107f is formed integrally with the flange
portion 107a, while the inner rib 101c is formed integrally with
the cover 101. The outer rib 107f and the inner rib 101c are
arranged in such a manner that a space 23 is defined between the
outer rib 107f and the inner rib 101c. In the space 23 defined
between the outer rib 107f and the inner rib 101c, a seal 18 that
is annular and of circular cross section is provided on the top
surface 107b of the flange portion 107a. A guide rib 101d is
provided in the outer edge portion 101a of the cover 1 and projects
downwardly in a radially inside position nearer to the center of
the opening 107 than that of the inner rib 101c. The seal 18 may be
of rectangular cross section or otherwise shaped as far as it
exerts an appropriate sealing capability.
[0147] Around an outside wall provided around the opening 107, an
annular member 108 that is larger in diameter than this opening 107
and made of metal is provided. A separate retainer 109 made of
metal is provided in such a manner that one end portion (outer
peripheral portion) of the retainer 109 is in contact with the
annular member 108 while the other end portion (inner peripheral
portion) of the retainer 109 is in contact with an outer edge
portion 101a of the cover 101 that closes the opening 107. The
retainer 109 is fastened with a plurality of bolts 111 and nuts
113, and the cover 101 is thereby fastened over the opening 107. In
the present embodiment, eight pairs of bolts 111 and nuts 113 are
employed to fasten the retainer 109.
[0148] A description will now be directed to the cover-mounting
structure of a fuel tank having the above construction in
operation. As shown in FIG. 6(b), the flange portion 107a is formed
at the edge of the opening 107 provided in the tank body 102 made
of plastic; the outer rib 107f projects upwardly from the outer
edge 107e of the top surface 107b of the flange portion 107a; and
the inner rib 101c projects downwardly from the undersurface of the
outer edge portion 101a of the cover 101 toward the top surface
107b of the flange portion 107a. Since the outer rib 107f and the
inner rib 101c are disposed so that the space 23 is defined between
the outer rib 107f and the inner rib 101c as described above, the
space 23 is provided between the outer rib 107f and the inner rib
101c and the seal 18 that is annular and of circular cross section
may be provided in the space 23. Specifically, the seal 18 is
fitted under a tension on an outer cylindrical surface of the inner
rib 101c, and thereafter the cover 101 is placed over the opening
107. On the other hand, the seal 18 may be placed on the top
surface 107b of the flange portion 107a before the cover 101 is
placed thereon over the opening 107. In the event, the outer rib
107f is brought into contact with the undersurface 101b of the
outer edge portion 101a of the cover 101, and thus a leak that
would occur between the opening 107 and the cover 101 can be
prevented. When the cover 101 is attached to close the opening 107,
the guide rib 101d serves as a positioning guide. Accordingly, the
cover 101 can be mounted on the portion of the tank body 102 of the
fuel tank T where the opening 107 is provided in such a manner as
to hermetically close the opening 107.
[0149] As the cover 101 is placed and brought into contact with the
outer rib 107f provided on the outer edge 107e of the flange
portion 107a formed at an edge of the opening 107 of the tank body
102, the bolts 111 are fitted into retainer holes 109a provided in
the one end portion (outer peripheral portion) of the retainer 109
and the other end portion (inner peripheral portion) of the
retainer 109 comes into contact with the outer edge portion 101a of
the cover 101. Thereafter, the nuts 113 are screwed on and the
retainer can be fixed firmly onto the tank body 102 with the cover
101 closed hermetically.
[0150] The annular member 108 that is insert-molded in the tank
body 102 made of plastic is a metal member, and the bolts 111 that
are embedded integrally in this annular member 108 made of metal
are metal members as well; therefore, the retainer 109 that is a
metal member can be fastened up with the nuts 113. Accordingly, the
cover 101 can be fixed and kept in good and close contact with a
portion around the opening 107 of the plastic tank body 102.
[0151] Next, a description will be given of relative positioning of
the outer rib 107f, the inner rib 101c and the seal 18 that are
arranged so as to achieve the good and close contact. FIG. 7 is an
enlarged and exploded sectional view for explaining the relative
positioning of the opening 107 and the cover 101 included in the
ninth embodiment. As shown in FIG. 7, the seal 18 that is annular
and of circular cross section is placed on the top surface 107b of
the flange portion 107a of the opening 107. The seal 18 is disposed
between the outer rib 107f and the inner rib 101c, and these ribs
107f and 101c are so designed that the height h of the outer rib
107f is greater than the height k of the inner rib 101c (h>k).
As a result, when the cover 101 is placed on the top surface 107b
of the flange portion 107a of the opening 107, the outer rib 107f
comes into contact with the undersurface of the outer edge portion
101a of the cover 101. In that event, since the height k of the
inner rib 101c is somewhat shorter than the height h of the outer
rib 107f, the inner rib 101c and the top surface 107b of the flange
portion 107a are disposed with a little clearance left
therebetween, or are configured to lightly touch. As shown in FIG.
6(b), when the outer rib 107f comes into contact with the
undersurface 101b of the outer edge portion 101a of the cover 101,
the seal 18 that is circular in cross section is pressed by the
undersurface 101b of the outer edge portion 101a of the cover 101,
and becomes deformed so as to conform to the shape of the space 23
defined between the outer rib 107f and the inner rib 101c, so that
a good hermetical sealing performance can be achieved.
Tenth Embodiment
[0152] FIG. 8 is an enlarged sectional view of a modified example
of the arrangement shown in FIG. 6 (b). The tenth embodiment
exemplifies a structure in which a soft resin having a fuel barrier
property against HDPE (high-density polyethylene) with solubility
parameter of 11 or greater, or a soft EVOH (alcohol copolymer) is
employed as a material for a seal guide.
[0153] In FIG. 8, the same elements as in FIG. 6(b) are designated
by the same reference numerals, and a description thereof will be
omitted.
[0154] As shown in FIG. 8, a cover 121 is mounted over an opening
127 provided in a tank body 122 made of plastic. At an edge of the
opening 127 provided in the tank body 122 made of plastic is formed
a flange portion 127a, and an outer rib 127f is provided which
projects upwardly from an outer edge 127e of a top surface 127b of
the flange portion 127a. A seal guide 21 that is an annular member
shaped like a letter L in cross section so as to conform to the
shape of a corner at an inner edge 127c of the top surface 127b of
the flange portion 127a is fitted on the inner edge 127c of the
flange portion 127a. A space 22 is defined between the outer rib
127f and the seal guide 21. In the space 22, a seal 18 is
provided.
[0155] A description will now be directed to the cover-mounting
structure of a fuel tank having the above construction in
operation. A shown in FIG. 8, the tenth embodiment of the
cover-mounting structure is an exemplary embodiment resulting from
modification of the cover 101 and inner rib 101c of the ninth
embodiment. An undersurface of an outer edge portion 121a of the
cover 121 is configured to press the seal guide 21 directly.
Hereupon, the space 22 is defined between the outer rib 127f and
the seal guide 21, and the seal 18 can be provided in the space 22,
so that the cover 121 can be brought into secure and close contact
with a portion around the opening 127, thereby achieving a good
hermetical sealing performance. Accordingly, the opening 127 can be
hermetically closed by the cover 121. On the other hand, the guide
rib 121d serves as a positioning guide when the cover 121 is
mounted over the opening 127. As described above, while pressing
the seal guide 21, the cover 121 comes in contact with the outer
rib 127f at the same time, and thus the cover 121 can hermetically
close the opening 127. Moreover, the seal guide 21 is formed of a
soft resin having a fuel barrier property against HDPE
(high-density polyethylene) with solubility parameter of 11 or
greater, or of a soft EVOH (alcohol copolymer), and thus has an
excellent layer structure, so that a good and close contact can be
achieved. Further, the seal guide 21 thus has an excellent
flexibility and an excellent barrier property, so that a good
hermetical sealing performance and an inhibitive effect of
preventing HC (hydrocarbon) from being transmitted can be achieved
as a sub-seal.
[0156] Although some preferred embodiments have been described
above, it is to be understood that the present invention is not
limited to the above-described embodiments, and modifications may
be made as appropriate which fall within the scope of the present
invention without departing the spirit thereof. For example, in the
aforementioned embodiments, the outer rib is disposed in a radially
outside position with respect to the inner rib, but the relative
positioning may be configured vice versa.
Eleventh Embodiment
[0157] FIG. 9 is an enlarged sectional view of a portion
corresponding to portion B of FIG. 1. As shown in FIG. 9, a discal
cover 141 is attached over a round opening 147 provided in a tank
body 142 and fastened with a retainer 149. A metal ring 10 is
annularly provided between an undersurface of the retainer 149 and
a top surface of an outer edge portion of the cover 141, and a seal
18 is annularly provided between an undersurface of the outer edge
portion of the cover 141 and a top surface of a portion around the
opening 147 so as to hermetically seal an interstice that could
develop between the cover 141 and the opening 147.
[0158] A description will be given more in detail with reference to
FIG. 10. FIG. 10 is a partial sectional view showing portion E of
FIG. 9 and illustrates a cover-mounting structure of a fuel tank T.
As shown in FIG. 10, the cover-mounting structure of a fuel tank T
is constructed in such a manner that the cover 141 in which pump
fittings (not shown) are mounted is attached over the opening 147
of the tank body 142 with the cover 141 being pressed by the
retainer 149 to hermetically close the opening 147. The seal
(O-ring) 18 is put between a top surface 147b of a portion around
the opening 147 and an undersurface 141b of the outer edge portion
of the cover 141. Right (along a vertical axis) above the position
in which the seal 18 is placed, the metal ring 10 is provided
between a top surface 141a of the outer edge portion of the cover
141 and an undersurface (pressing surface) 149a of an inner edge
portion of the retainer 149. The metal ring 10 has a spring tension
exerting a force in such a direction that a portion of the fuel
tank T where the opening 147 is provided is pressed by the cover
141.
[0159] To this end, a flange portion 147a is formed at an edge of
the opening 147 provided in the tank body 142, and the seal 18 is
provided annularly on a top surface 147b of the flange portion
147a, so that an interstice that could develop between the opening
147 and the cover 141 is hermetically sealed. Around the opening
147, an annular member 148 that is larger in diameter than the
opening 147 and made of metal is provided. The annular member 148
is formed integrally with the tank body 142, and embedded therein
by an undersurface 147c of the flange portion 147a, a recessed
outside wall 147d provided around the opening 147, and a tank
outside wall 142a. Accordingly, the annular member 148 is fixed,
integrally with the tank body 142, around a peripheral edge of the
opening 147 of the tank body 142. Bolts 151 are then screwed in the
annular member 148, and the retainer 149 is fitted so as to have
the bolts 151 inserted therein, and further the retainer 149 is
fastened down by screwing nuts 152 from above on the bolts 151.
Consequently, the retainer 149 is fixed on the annular member
148.
[0160] A guide rib 141d is provided on an undersurface of the
discal cover 141 annularly so as to fit on an inner periphery
defining the opening 147, and an outer cylindrical surface of a
lower end portion of the guide rib 141d is chamfered to facilitate
fitting. This guide rib 141d serves to position the cover 141 so
that the cover 141 may not shift with respect to the opening 147.
The undersurface 141b of the outer edge portion 141a of the cover
141 floats over an outer rib 147f formed at an outer edge of the
flange portion 147a, due to support of the seal 18. Therefore, the
outer rib 147f is provided annularly with a little clearance left
from the undersurface 141b of the outer edge portion 141a of the
cover 141. On an undersurface of the round cover 141 in a radially
inside position nearer to the center thereof than that of the outer
rib 147f, an inner rib 141c is provided with a clearance left from
the top surface 147b of the flange portion 147a, or so disposed as
to lightly touch the top surface 147b of the flange portion 147a.
Thus, a space 16 is defined between the outer rib 147f and the
inner rib 141c, and the seal 18 is placed annularly in the space
16. Further, along a vertical axis above the seal location on the
top surface 147b of the flange portion 147a, the metal ring 10 is
placed on the top surface 141a of the outer edge portion of the
cover 141 and pressed down by the retainer 149.
[0161] Next, a description of the aforementioned metal ring 10 will
be given below. FIG. 11 schematically shows the metal ring 10; FIG.
11(a) is a plan view, and FIG. 11(b) is a vertical sectional view
taken along line F-F of FIG. 11(a). The metal ring 10 results from
stamping of spring steel followed by heat treatment to form an
annular metal disc on an undersurface of which is provided a recess
(groove) 10b along a peripheral edge portion by drawing or the
like. In the metal ring 10, slits 10a, 10a, . . . , of which eight
may be provided for example, are cut in radial directions at an
inner circumference of its circular shape.
[0162] A description will now be directed to the cover-mounting
structure of a fuel tank T having the above construction in
operation. As shown in FIG. 10, when the retainer 149 is fastened
to the annular member 148 with the bolts 151 and the nuts 152, a
downward load is applied to the top surface of the metal ring 10
that is placed on the top surface 141a of the outer edge portion of
the cover 141 by the undersurface 149a of the inner edge portion of
the retainer 149. Thus, the undersurface 149a of the inner edge
portion of the retainer 149 presses the metal ring 10, and the
cover 141 disposed under the metal ring 10 is thereby pressed by
the metal ring 10. Meanwhile, the seal 18 is placed between the
cover 141 and the portion around the opening 147, and therefore,
the opening 147 is hermetically closed by the cover 141.
[0163] On the other hand, the portion in the tank body 142 where
the opening 147 is provided and the cover 141 are formed of
plastic, and may therefore deform over time and could become unable
to maintain its initially achieved accurate positioning and
adequate strength between joined portions of the tank body 142
where the opening 147 is provided and the cover 141. Nevertheless,
the metal ring 10 put between the retainer 149 and the cover 141
makes up for the change caused by the time-varying plastic
materials in positioning and strength between the joined portions
of the cover 141 and the tank body 142 where the opening 147 is
provided, with the help of spring tension of the metal ring 10, and
can thereby maintain a predetermined level of positioning accuracy
and adequate strength between the joined portions thereof. The
deformation over time as described above is called "creep" strain,
referring to the phenomenon in which plastic deformation progresses
gradually with the lapse of time due to the application of
sustained stress. To address this phenomenon, the spring tension of
the metal ring 10 presses the cover 141 supported by the seal 18 in
a floating manner. Even after the top surface 147b of the flange
portion 147a or the undersurface 141b of the outer edge portion
141a of the cover 141 becomes so deformed as to assume a hollowed
surface shape as a result of the creep strain, such a shape
resulting from the creep strain may be conformed to so that the
amount of compression of the seal (O-ring) 18 may be preserved,
which makes it possible to inhibit the decrease of reaction force
of the seal packing, and to thereby inhibit the decrease of
hermetical sealing performance between the cover 141 and the tank
body 142. The metal ring 10 that may operate as described above
will come up for further discussion in detail.
[0164] As shown in FIG. 10, the retainer 149 is fastened to the
annular member 148, so that the top surface of the metal ring 10 is
pressed by the undersurface 149a of the inner edge portion of the
retainer 149. Hereupon, the metal ring 10, in which the slits 10a,
10a, . . . are made as shown in FIG. 11, are provided for example
with eight slits 10a, 10a, . . . arranged in evenly spaced
positions, which deforms the metal ring 10 in a manner that forces
the recess (groove) 10b to widen. In other words, during the time
when the metal ring 10 deforms in a manner that forces the groove
(recess) 10b to widen, the inner edge of the metal ring 10 expands
inwardly, and those slits 10a, 10a, . . . serve to absorb
measurable strains that would be caused all that while. To be more
specific, the slits 10a, 10a, . . . each function as a groove for
absorbing measurable strains that would be induced when the metal
ring 10 is caused to exhibit a spring tension. This allows the
metal ring 10 to exert its spring tension.
[0165] As shown in FIG. 10, the metal ring 10 is provided on the
top surface 141a of the outer edge portion of the cover 141 right
above the position (along a vertical axis) in which the seal is
placed on the top surface 147b of the flange portion 147a, and is
pressed by the undersurface (hereinafter referred to as pressing
surface) 149a of the inner edge portion of the retainer 149. In
this state, the pressing surface 149a of the retainer 149, the
metal ring 10, the top surface 141a of the outer edge portion of
the cover 141, the seal 18, and the position in which the seal 18
is placed on the flange portion 147a are arranged along one and the
same axis, which allows the cover 141 to be firmly clamped between
the retainer 149 and the tank body 142, so that the cover 141 can
be firmly fixed over the opening 147.
Twelfth Embodiment
[0166] The following discussion will be directed to a twelfth
embodiment. The twelfth embodiment is different from the eleventh
embodiment in that the twelfth embodiment has no metal ring 10, and
that a retainer 169 that will be described later (see FIG. 12) has
its own spring tension.
[0167] In describing the twelfth embodiment, the same elements as
in the eleventh embodiment are designated by the same reference
numerals, and a description thereof will be omitted.
[0168] FIG. 12 is an enlarged sectional view showing a portion
corresponding to portion B of FIG. 1. As shown in FIG. 12, a discal
cover 161 is attached over a round opening 167 provided in a tank
body 162 and fastened with a retainer 169. The retainer 169 is
formed to have a corrugated portion extending on a top surface of
an outer edge portion of the cover 161, to press the cover 161 with
its spring tension, and is in contact with the top surface of the
cover 161 under pressure. A seal 18 is annularly provided between a
top surface of a portion around the opening 167 and the cover 161
and so as to hermetically seal an interstice that could develop
between the opening 167 and the cover 161.
[0169] A description will be given more in detail with reference to
FIG. 13. FIG. 13 is a partial sectional view showing portion G of
FIG. 12 and illustrates a cover-mounting structure of a fuel tank
T. As shown in FIG. 13, the cover-mounting structure of a fuel tank
T is constructed in such a manner that the cover 161 in which pump
fittings (not shown) are mounted is attached over the opening 167
of the tank body 162 made of plastic with the cover 1 being pressed
by the retainer 169 to hermetically close the opening 167. The seal
18 is put between a top surface 167b of the portion around the
opening 167 and an undersurface 161b of the outer edge portion of
the cover 161.
[0170] To this end, a flange portion 167a is formed at an edge of
the opening 167 provided in the tank body 162, and the seal 18 is
provided annularly on a top surface 167b of the flange portion
167a, so that an interstice that could develop between the opening
167 and the cover 161 is hermetically sealed. Around the opening
167, an annular member 168 made of metal is provided in such a
manner as described in relation to the eleventh embodiment. Bolts
171 are screwed in this annular member 168, and the retainer 169 is
fitted so as to have the bolts 171 inserted therein, and further
the retainer 169 is fastened down by screwing nuts 172 from above
on the bolts 171. Consequently, the retainer 169 is fixed on the
annular member 168.
[0171] Under the discal cover 161, an outer rib 167f, an inner rib
161c, and a guide rib 161d are provided to define a space 16, and
the seal 18 is provided in the space 16, in such a manner as
described in relation to the eleventh embodiment.
[0172] Next, a description of the aforementioned retainer 169 will
be given more in detail below. FIG. 14 is a schematic illustration
of the retainer 169; FIG. 14(a) is a plan view, and FIG. 14(b) is a
vertical sectional view taken along line H-H of FIG. 14(a). The
retainer 169 is an annular metal disc resulting from stamping of
spring steel followed by heat treatment, and is formed annularly so
as to surround the cover 161. In the retainer 169, slits 179a,
179a, . . . of which eight may be provided for example, are cut in
radial directions at an inner circumference of its circular shape.
An inner edge portion of the retainer 169 has a corrugated portion
169c formed along a peripheral edge thereof by drawing or the like.
Reference numeral 169b denotes a round hole. In the round holes
169b are inserted the bolts 171 (see FIG. 13), on which the nuts
(see FIG. 13) are in turn screwed down; thus, the retainer 169 is
fixed on the annular member 168.
[0173] A description will now be directed to the cover-mounting
structure of a fuel tank T having the above construction in
operation. As shown in FIG. 13, when the retainer 169 is fastened
to the annular member 168 with the bolts 171 and the nuts 172, an
undersurface 169d of the inner edge portion of the retainer 169
presses the cover 161. Meanwhile, the seal 18 is placed between the
cover 161 and the portion around the opening 167, and therefore,
the opening 167 is hermetically closed by the cover 161.
[0174] On the other hand, the portion in the tank body 162 where
the opening 167 is provided and the cover 161 are formed of
plastic, and may therefore deform over time and could become unable
to maintain its initially achieved accurate positioning and
adequate strength between joined portions of the tank body 162
where the opening 167 is provided and the cover 161. Nevertheless,
the spring tension of the retainer 169 serves to make up for the
change caused by the time-varying plastic materials in positioning
and strength between the joined portions of the cover 161 and the
tank body 162 where the opening 167 is provided, and can thereby
maintain a predetermined level of the positioning accuracy and
adequate strength between the joined portions thereof. The spring
tension of the retainer 169 makes it possible to conform to the
deformed shape as a result of the creep strain of flange portion
167a and the outer edge portion of the cover 161, thereby
inhibiting the hermetical sealing performance from lowering, as in
the first embodiment. The retainer 169 that may operate as
described above will come up for further discussion in detail.
[0175] The retainer 169, in which the slits 169a, 169a, . . . are
made as shown in FIG. 14, is fastened to the annular member 168, so
that a top surface 161a (see FIG. 13) of the outer edge portion of
the cover 161 is pressed by the undersurface 169d of the inner edge
portion of the retainer 169. Hereupon, the retainer 169 are
provided for example with the slits 169a, 169a, . . . arranged in
eight positions, which deforms the retainer 169 in a manner that
forces the corrugated portion 169c of the retainer 169 to widen. In
other words, during the time when the retainer 169 deforms in a
manner that forces the corrugated portion 169c of the retainer 169
to widen, the inner edge of the retainer 169 expands inwardly, and
those slits 169a, 169a, . . . serve to absorb measurable strains
that would be caused all that while. To be more specific, the slits
169a, 169a, . . . each function as a groove for absorbing
measurable strains that would be induced when the retainer 169 is
caused to exhibit a spring tension. This allows the retainer 169 to
exert its spring tension.
[0176] As shown in FIG. 13, the undersurface (pressing surface)
169d of the inner edge portion of the retainer 169 comes in contact
with the top surface 161a of the outer edge portion of the cover
161 right above the position (along a vertical axis) in which the
seal 18 is placed on the top surface 167b of the flange portion
167a, and presses the top surface 161a of the outer edge portion of
the cover 161. In this state, the pressing surface 169d of the
retainer 169, the top surface 161a of the outer edge portion of the
cover 161, the seal 18, and the position in which the seal 18 is
placed on the flange portion 167a are arranged along one and the
same axis, which allows the cover 161 to be firmly clamped between
the retainer 169 and the tank body 162, so that the cover 161 can
be firmly fixed over the opening 167.
[0177] The fuel pump 6 (see FIG. 1) is integrally mounted in the
cover 161, so that no clearance remains between the pump fittings
and the cover; therefore, the hermetical sealing performance
between the cover (mount plate) 161 and the tank body 162 can be
improved.
[0178] Since the cover 161 is mounted on the tank body 162 using a
metal fastening means (retainer 169) to which a spring tension is
applied, even when a joint portion between the fuel pump 6 and the
tank body 162 has deformed over time, the seal 18 is invariably
brought into close contact with the surface where the seal is
placed under an adequate pressure, so that a predetermined sealing
performance can be achieved.
[0179] Since a spring tension is applied to the entire perimeter of
the metal fastening means (retainer 169), any partial decrease in
sealing performance thereof can be avoided.
[0180] Moreover, since the spring elasticity, of the retainer
itself or of a separate member such as a metal ring 10, is caused
to reside in a joint portion to address the problem of decreasing
reaction force of seal packing due to the creep strain, its
spring-like portion conforms to the crept portion and the initially
given reaction force of the seal packing can be preserved even
after creeping has progressed, so that the decrease in hermetical
sealing performance of the tank body 162 incorporating the fuel
pump 6 can be prevented.
[0181] Although preferred embodiments have been described above,
the present invention is not limited to the above-described
embodiments, and modifications may be made as appropriate which
fall within the scope of the present invention without departing
the spirit thereof. For example, the aforementioned embodiments
provides eight slits arranged annularly in the metal ring or
retainer in order to enable the metal ring or retainer to exhibit a
spring tension, but these slits may be cut either in radial
directions at an inner circumference of its circular shape or in
radial directions at an outer circumference of its circular shape.
Further, the number of the slits may not be limited to eight.
Thirteenth Embodiment
[0182] FIG. 15 is a perspective view schematically showing a fuel
tank (plastic container) according to a thirteenth embodiment of
the present invention. FIG. 16(a) is a vertical sectional view
taken along line I-I of FIG. 15; and FIG. 16(b) an illustration of
portion Q of FIG. 16(a) as viewed from arrow J. FIG. 17 is an
enlarged sectional view of portion Q of FIG. 16(a).
[0183] The terms fuel tank and tank body used in describing the
present embodiment refer respectively to plastic container and
plastic container body defined in the claims. A cover will
hereinafter be referred to as cover-like member.
[0184] As shown in FIGS. 15 through 17, a fuel tank T is comprised
of a tank body 192 made of plastic, at least part of which is made
of a barrier material, with an opening 197 provided in the tank
body 192. Mounted over the opening 197 is a cover-like member 192
(see FIG. 17) composed of a pump module and other components. In an
external surface of the tank body 192 is provided a recess (groove)
192b which extends circularly around a peripheral edge portion of
the opening 197, and an annular member 198 is insert-molded in the
recess 192b during a plastic molding process. The annular member
198 is so shaped as to be kept from obstructing the thermal
contraction of the tank body 192 made of plastic when the tank body
192 is contracted by heat, or shaped like a flat plate having no
irregularity on its surfaces. Moreover, the annular member 198 is
provided with a plurality of bolts 204 protruding from annularly
arranged positions along a peripheral edge of the opening 197.
Reference character 192a denotes a drainage passage. The drainage
passage 192a is provided in the external surface of the tank body
192. Provision of the drainage passage 192a as described above
forms a structure in which the drainage passage 192a is configured
to connect interfaces between the annular recess 192b and bottom
surface(s) of at least one of the annular member 198 and the bolts
204, and to connect spaces around the above interfaces, thereby
allowing water to drain to the outside to prevent the formation of
rust. Here, as illustrated, a single drainage passage 192 is
provided in the external surface of the tank body 192; it is
however understood that the number of passages may be increased as
appropriate.
[0185] FIG. 18 represents enlarged sectional views showing portion
L of FIG. 17; FIG. 18(a) is a sectional view of a portion around
the opening 197 immediately after plastic molding; and FIG. 18(b)
is a sectional view of the portion around the opening 197 which has
completely been thermally contracted after plastic molding. As
shown in FIG. 18(b), a cover-like member 191, which is illustrated
by a broken line, is mounted over the opening 197 of a fuel tank T,
and this cover-like member 191 is fastened to a tank body 192 using
a retainer 199, a nut 202 and other elements. This allows the tank
body 192 to be hermetically closed. The tank body 192 is provided
with a recess 192b provided annularly around a peripheral edge of
the opening 197 with an annular member 198 made of metal being
embedded integrally in the recess 192b. Reference character 200
denotes a space, and the space 200 is provided between an outer
inside wall 192c of the recess 192b provided annularly around the
opening 197 and at least one of an outer cylindrical end face 198a
of the annular member 198 (see FIG. 18(a)) and an outer cylindrical
end faces 204c of heads 204a of bolts 204 (see FIG. 18(a)), serving
as an allowance M for thermal contraction of plastic material.
Therefore, the space 200 appears in the tank body 192 immediately
after plastic molding, but disappears when the thermal contraction
has been completed after plastic molding as shown in FIG. 18(b). At
this stage, the space 200 is occupied by the annular member 198
abutted against the outer inside wall 192c of the recess 192 with
no space left in actuality. The bolts 204 are provided with their
screw thread portions 204b oriented upward.
[0186] FIG. 19 is a sectional view taken along line K-K of FIG.
16(b), and illustrates a section of the drainage passage 192a. The
drainage passage 192a is led out from a bottom surface of the space
200 formed in the tank body 192 immediately after plastic molding,
to an external surface of the tank body 192. The drainage passage
192a is provided to drain water that tends to stay in or around
interfaces between the recess 192b and the bottom surfaces of the
annular member 198 and bolts 204 (see FIGS. 16 and 18). For that
purpose, the bottom surface of the space 200 formed adjacent to the
annular recess 192b immediately after plastic molding is in a
position lower than the bottom surfaces of the annular member 198
and the bolts 204. In this instance, the cross-sectional geometry
of the recess 192b is not limited to any particular shape as long
as it allows water to drain out.
[0187] A description will now be directed to the cover-mounting
structure of a fuel tank (plastic container) having the above
construction in operation. Referring to FIGS. 18(a) and 18(b), the
section of a portion around the opening 197 of the tank body 192
immediately after plastic molding (FIG. 18(a)) and the section of a
portion around the opening 197 of the tank body 192 which has
completely been thermally contracted after plastic molding (FIG.
18(b)) are explained hereinafter in a contrastive manner. As shown
in FIG. 18(a), the outer inside wall 192c of the recess immediately
after plastic molding has the space 200, as an allowance M for
thermal contraction of plastic material of the tank body 192 that
will be thermally contracted immediately after plastic molding,
formed between the outer inside wall 192c and at least one of the
outer cylindrical end face 198a of the annular member 198 and the
outer cylindrical end faces 204c of the heads 204a of the bolts
204. As shown in FIG. 18(b), when the thermal contraction has been
completed after plastic molding, the recess 192b that is provided
annularly has been thermally contracted in a direction as indicated
by a hollow arrow. Therefore, at least one of the outer cylindrical
end face 198a of the annular member 198 made of metal provided in
the recess 192b and the outer cylindrical end faces 204c of the
heads 204a of the bolts 204 is brought into contact with the outer
inside wall 192c of the recess 192b and fixed. Thus, at least one
of the outer cylindrical end face 198a and the outer cylindrical
end faces 204c has no gap left between the outer inside wall 192c
and itself. Consequently, at least one of the annular member 198
and the bolts 204 can be joined firmly with the tank body 192, so
that the excellent hermetical sealability of the opening 197 can be
maintained and the mounting accuracy of the annular member can be
improved.
[0188] As shown in FIG. 19, the bottom surface of the space 200
formed in the annular recess 192b is arranged in a position lower
than the bottom surfaces of the annular member 198 and the bolts
204. The drainage passage 192a led out from the bottom surface of
the space 200 is provided in the external surface of the tank body
192. Accordingly, water that tends to stay in or around interfaces
between the recess 192b and the bottom surfaces of the annular
member 198 and bolts 204 is drained out. Consequently, in an
automobile to which the above-described structure is applied, a
plastic fuel tank having an excellent quality can be installed.
[0189] Although preferred embodiments have been described above,
the present invention is not limited to the above embodiments, and
any modifications may be made as appropriate without departing from
the scope and spirit of the present invention. For example, only
one drainage passage 192a is provided on the external surface of
the tank body 192 in the present embodiment, but the number of the
drainage passages 192a may be increased as appropriate. Further,
the bolts provided in the annular member are not limited to
particular embodiments in respect to whether the bolts have heads
or not, or how the bolts are fastened to the annular member, as far
as their screw thread portions are oriented upward. Furthermore,
the present embodiment has been described on the premise that it is
applied to a fuel tank of an automobile, but the applicable parts
are not limited to the fuel tank of the automobile and, needless to
say, generally include plastic parts shaped into a container.
Fourteenth Embodiment
[0190] A cover-mounting structure of a plastic container according
to a fourteenth embodiment of the present invention will be
described hereinafter with reference made to drawings as
appropriate. Hereupon, the positions and directions will be
represented with respect to the normal state of operation of the
plastic container.
[0191] FIG. 20, to which reference is made at first, is an exploded
perspective view of a cover-mounting structure of a plastic
container according to the fourteenth embodiment of the present
invention in which the plastic container is used for a fuel tank of
an automobile. FIG. 21 shows a cover-mounting structure of a
plastic container, of which constitutional parts as shown in FIG.
20 have been assembled together; (a) is a plan view, (b) is a
vertical sectional view taken along line N-N of (a), and (c) is a
vertical sectional view taken along line P-P of (a). In FIGS. 20
and 21, the constitutional parts that are not directly related to
the present invention, such as a pump module, are not
illustrated.
[0192] Referring now to FIG. 20, a description will be given of
constitutional parts of a cover-like member mounting structure of a
fuel tank T according to the fourteenth embodiment of the present
invention. The fuel tank T corresponds to "plastic container"
defined in claims.
[0193] The fuel tank T has a round opening 217 on top of a tank
body 212. A flange portion 217a is provided at an edge of the
opening 217. A cover 211 for closing the opening 217 is discal, and
on an inside thereof are provided a fuel feed passage for supplying
an automotive engine with fuel fed from a pump module (not shown),
a fuel recirculation passage through which unconsumed fuel flows
back from the engine, and other components. The cover 211 is as
large in diameter as to substantially cover the flange portion 217a
when it is mounted on the tank body 212. An annular seal 18 is
provided between the flange portion 217a and the cover 211. The
seal 18 is not limited in material, and may be formed of, for
example, a blend of acrylonitrile-butadiene rubber and polyvinyl
chloride, or the like.
[0194] An annular member (hereinafter referred to as annular
supporting part 218) is provided on an outside wall 212a of the
tank body 212 so as to surround the opening 217. Provided in a gap
between the supporting part 218 and the outside wall 212a of the
tank body 212, on which the supporting part 218 is fixed, are a
plurality of through holes 205, . . . , (for example, eight of
which are provided in the present embodiment and among which six
are illustrated) which are substantially evenly spaced along its
circumference. Moreover, in the supporting part 218 are provided a
plurality of bolts 221, . . . (for example, eight of which are
provided in the present embodiment), which are located at positions
substantially evenly spaced around its circumference but not
coincide with the positions of the through holes 205, . . . and are
fitted and held upright in holes 218a, . . . provided in the
supporting part 218. Hereupon, the supporting part 218 may be fixed
on the outside wall 212a of the tank body 212 by various means,
which is not limited to a particular method but may include for
example welding and the like. Moreover, the bolts 8, . . . may be
fixed on the supporting part 218 by various means, which is not
limited to a particular method but may include for example screwing
and the like.
[0195] An annular retainer (hereinafter referred to as annular
mounting part 219) includes an inner peripheral portion 219a to
rest against the cover 211, and an outer peripheral portion 219c
provided with retaining holes 219b, . . . through which bolts 221,
. . . are to be inserted. The retaining holes 219b, . . . are
fitted on the bolts 221, . . . while the cover 211 is being pressed
down by the inner peripheral portion 219a, and the outer peripheral
portion 219c is then fastened on the supporting part 218 using the
bolts 221, . . . and the nuts 222, . . . , thereby allowing the
cover 211 to be mounted on the fuel tank body 212. Moreover, along
a bend 219d of the mounting part 219 are provided a plurality of
through holes 206, . . . (for example, eight of which are provided
in the present embodiment), which are substantially evenly spaced
around its circumference.
[0196] The through holes 206, . . . are provided at locations as
shown in FIG. 21(a) when the mounting part 219 fixed on the
supporting part 218 is viewed from the mounting part 219 side,
i.e., on phantom lines .beta. produced from the center .alpha. to
the through holes 206 . . . .
[0197] The materials of which the supporting part 218, mounting
part 219, bolts 221, . . . and nuts 222 are formed are not limited,
but may preferably be formed of metal in that the cover 211 is
firmly fixed and its mount spot is resistant to deformation.
Further, in order to prevent rust that would be formed when these
metal parts are submerged in water during submergence leak test or
the like, the metal to be used may preferably be antirust metal
such as stainless steel or the like.
[0198] Next, a description will be given of procedural steps for
mounting the cover 211 onto the fuel tank body 212 with reference
to FIG. 20.
[0199] First, the seal 18 is placed on top of the flange 217a
around the opening 217, and the cover 211 is then placed on the
seal 18. Further, the retaining holes 921b, . . . provided in the
outer peripheral portion 219c of the mounting part 219 are fitted
on the bolts 221, . . . while a top surface 211a of the outer edge
portion of the cover 211 is being pressed down with the inner
peripheral portion 219a of the mounting part 219. Subsequently, the
nuts 222, . . . are screwed on the bolts 221, . . . , and the cover
211 is thereby mounted on the fuel tank body 212.
[0200] The following description will be directed to operation and
advantageous effects of the cover-like member mounting structure of
a fuel tank T according to the fourteenth embodiment of the present
invention with reference to FIG. 21.
[0201] In FIG. 21(a), which illustrates a cover-mounting structure
mounted by following the aforementioned process steps, FIG. 21(b),
which is a vertical sectional view taken along line N-N thereof,
illustrates a vertical section of a portion where the mounting part
219 is fixed on the supporting part 218. As shown in FIG. 21(b),
the mounting part 219, with the inner peripheral portion 219a
thereof pressing down the top surface 211a of the outer edge
portion of the cover 211, extends out to the supporting part 218,
and the outer peripheral portion 219c of the mounting part 219 is
fastened using the bolts 221 and the nuts 222, thereby allowing the
cover 211 to be mounted onto the fuel tank body 212 in a firm and
hermetical manner.
[0202] When the cover 211 is firmly mounted on the fuel tank body
212, the seal 18 clamped between an undersurface 211b of the outer
edge portion of the cover 211 and a top surface 217b of the flange
portion 217a around the opening 217 is pressed so that a secure and
good hermetical sealing performance can be achieved.
[0203] Next, a description will be given with reference to FIG.
21(c), which is a vertical sectional view taken along line P-P of
FIG. 21(a). FIG. 21(c) shows a vertical section including one
through hole 205 and one through hole 206. Each through hole 205 is
provided between the supporting part 218 and the outside wall 212a
of the fuel tank body 212 on which the supporting part 218 is
fixed. Each through hole 206 is provided in the bend 219d of the
mounting part 219. This allows water to flow through the through
holes 205 and the through holes 206, and to fill up space 207
swiftly, when the fuel tank T on which the cover 211 is mounted by
following the aforementioned process steps is submerged into a
water tank during a submergence leak test. Accordingly, no extra
time to wait is required from submergence of the fuel tank T into
the water tank, to introduction of pressure-regulated air;
therefore, the time for testing can be reduced. Moreover, the
through hole 26 is provided so as to allow the space 207 to
immediately communicate at its top, and thus air that was in the
space 207 at the time of submergence of the fuel tank T into the
water tank is discharged through the through holes 206 swiftly. As
a result, the evolution of bubbles derived from air in the space
207 during the test can be prevented without fail, and the
submergence leak test can be performed with improved accuracy.
[0204] Further, since the through holes 205 are provided between
the supporting part 218 and the outside wall 212a of the fuel tank
body 212 on which the supporting part 218 is fixed, the through
holes 205 are provided so as to allow the space 207 to immediately
communicate at its bottom. This allows water with which the space
207 is filled to be discharged swiftly through the through holes
205 when the fuel tank T is raised from the water tank after the
submergence leak test has been carried out. Moreover, the through
holes 205 are provided so as to allow the space 207 to immediately
communicate at its top, and thus the pressure of air flowed into
the space 207 pushes water in the space 207, so that the water can
be discharged more swiftly. Accordingly, a process for drying the
fuel tank 1 after the test can be performed with increased ease,
and corrosion of constituent parts, which would result from
residual water after the test, can be prevented.
Fifteenth Embodiment
[0205] A cover-mounting structure of a fuel tank 220 according to a
fifteenth embodiment of the present invention will be described
hereinafter with reference to drawings as appropriate. Hereupon,
the fuel tank 220 corresponds to "plastic container" set forth in
claims.
[0206] FIGS. 22(a) and 22(b) to which reference is made herein
correspond to FIGS. 21(b) and 21(c) to which reference was made in
describing the fourteenth embodiment; FIG. 22(a) is a vertical
sectional view of a portion where a mounting part and a supporting
part are fastened, and FIG. 22(b) is a vertical sectional view of a
through hole.
[0207] As shown in FIG. 22(a), the fuel tank 220 made of plastic is
comprised of a fuel tank body 221 having a recess 221b provided on
an outer wall 221a thereof in which recess 221b a supporting part
223 is insert-molded with bolts 222 held upright and substantially
evenly spaced around a circumference. While a top surface 225a of
an outer edge portion of a cover 225 is being pressed by an inner
peripheral portion 224a of a mounting part 224, retainer holes 224b
of the mounting part 224 are fitted on the bolts 222, and the
mounting part 224 is fastened with nuts 226, so that the cover 225
is mounted on the fuel tank body 221 in a firm and hermetical
manner.
[0208] When the cover 225 is firmly mounted on the fuel tank body
221, a seal 28 clamped between an undersurface 225b of an outer
edge portion of the cover 225 and a top surface 227b of a flange
portion 227a around an opening 227 is pressed so that a secure and
good hermetical sealing performance can be achieved.
[0209] The fuel tank 220 is provided with through holes 229 and
through holes 230 as shown in FIG. 22(b). Each through hole 229 is
provided between the mounting part 224 and the supporting part 223,
and each through hole 230 is provided in a bend 224c of the
mounting part 224. Thus, since the fuel tank 220 has through holes
229 allowing the space 231 to immediately communicate at its bottom
and further has through holes 230 allowing the space 231 to
immediately communicate at its top, the same effects as in the
fourteenth embodiment can be achieved.
[0210] Further, the supporting part 223 is insert-molded in the
recess 221b, and thus firmly joined with the fuel tank body 221. As
a result, the hermetical sealing performance of the fuel tank 220
is improved.
[0211] The supporting part 223 is insert-molded with an allowance
232 for thermal contraction of the fuel tank body 221 provided as
indicated by dashed lines in FIG. 22, and thus the thermal
contraction of the fuel tank body 221 to the right in the drawing
that progresses as the temperature of plastic material becomes
cooler after the insert molding is completed brings an outer
cylindrical end face 223a of the supporting part 223 into contact
with a wall face 221c of the recess 221b. This allows the
supporting part 223 to be fixed with improved accuracy. The thermal
contraction of the fuel tank body 221 causes a space 233 to be made
between an inner cylindrical wall face 223b of the supporting part
223 and the fuel tank body 221.
[0212] Although a preferred embodiment has been described above,
the present invention is not limited the above-described
embodiment. For example, the bolts and nuts are used when the
mounting part is fixed on the supporting part in the present
embodiment, but the method of fixing the mounting part is not
limited thereto, as far as the method allows the mounting part to
be provided to extend out to the supporting part while pressing the
cover from outside whereby the mounting part can be fixed on the
supporting part.
[0213] The through holes as well are not limited to the above
embodiments, as far as the holes allow the space formed on a
plastic container body side of the mounting part to communicate
with outside.
[0214] Although the above-described embodiment provides an annular
seal between a flange portion provided around the opening of the
plastic container body and the cover, the present invention is not
particularly limited in terms of sealing means. For example, a
cover having a sealing capability may be used to hermetically close
the opening of the plastic container body to thereby prevent a
leak.
INDUSTRIAL APPLICABILITY
[0215] In a cover-mounting structure of a plastic container
according to the present invention, a seamless annular member is
embedded in a portion around an opening of a tank body made of
plastic to form an integral part thereof, and thus the strength of
fastening between the plastic tank body and the cover can be
improved.
[0216] In a cover-mounting structure of a plastic container
according to the present invention, an annular member assumes an
undivided ring-shaped geometry with no local rigidity variation
point that would be involved at seams of a ring-shaped geometry,
and thus good hermetical sealing performance between the tank body
and the cover can be stably achieved.
[0217] In a cover-mounting structure of a plastic container
according to the present invention, an annular member is not cut
into an external wall of the tank body made of plastic so as not to
sever a barrier layer of the plastic tank body, and thus the
possibility of affecting a layer structure thereof can be
eliminated.
[0218] In a cover-mounting structure of a plastic container
according to the present invention, insert bolts are provided
protrusively in an annular member, and with nuts screwed on the
bolts, a retainer can be firmly fastened; thus, the strength of
fastening between the plastic tank body and the cover can be
improved.
[0219] In a cover-mounting structure of a plastic container
according to the present invention, a screw hole is provided
vertically in an annular member, and with a bolt screwed into the
screw hole, a retainer can be firmly fastened; thus, the strength
of fastening between the plastic tank body and the cover can be
improved.
[0220] In a cover-mounting structure of a plastic container
according to the present invention, an annular member and a
retainer for fixing the annular member are formed of metal
materials, and thus the retainer can be firmly fastened, so that
the strength of fastening between the plastic tank body and the
cover can be improved.
[0221] In a cover-mounting structure of a plastic container
according to the present invention, a thread is formed on an outer
or inner cylindrical surface of an annular member, and thus the
annular member can be fastened firmly to a retainer, so that the
strength of fastening between the plastic tank body and the cover
can be improved.
[0222] In a cover-mounting structure of a plastic container
according to the present invention, an outer rib comes into contact
with a cover prior to an inner rib, which lightly touches or does
not touch a flange portion, and thus the outer rib can be brought
into secure and close contact with the cover; further, a space for
providing a seal can be made between the outer rib and the inner
rib, and thus excellent hermetical sealing performance can be
achieved.
[0223] In a cover-mounting structure of a plastic container
according to the present invention, an inner rib does not strongly
press a surface where a seal is placed, and thus deformation of the
surface where the seal is placed can be prevented so that good
hermetical sealing performance can be achieved.
[0224] In a cover-mounting structure of a plastic container
according to the present invention, a space is defined between an
outer rib projecting upwardly from an outer edge of a top surface
of flange portion, and a seal guide shaped like a letter L in cross
section so as to conform to a shape of a corner at an inner edge of
the top surface of the flange portion, and further a space where a
seal is placed can be made between the outer rib and the seal
guide; therefore, the outer rib can come into secure and close
contact with the cover, so that good hermetical sealing performance
can be achieved.
[0225] In a cover-mounting structure of a plastic container
according to the present invention, the seal guide is of a soft
resin having a fuel barrier property against HDPE (high-density
polyethylene) with solubility parameter of 11 or greater, or of a
soft EVOH (alcohol copolymer), and thus has an excellent
flexibility and an excellent barrier property, so that a good
hermetical sealing performance and an inhibitive effect of
preventing HC (hydrocarbon) from being transmitted can be achieved
as a sub-seal.
[0226] In a cover-mounting structure of a plastic container
according to the present invention, a metal ring has a spring
tension acting in such a direction that the portion of the plastic
container where the opening is provided is pressed by the cover,
and the spring tension serves to make up for the change in
positioning and strength between the joined portions of the cover
and a portion around the opening, and can thereby maintain a
predetermined level of the positioning accuracy and adequate
strength; therefore, the change caused by the time-varying plastic
materials in positioning and strength between the joined portions
of the cover (mount plate) and the tank body can be prevented from
lowering.
[0227] In a cover-mounting structure of a plastic container
according to the present invention, a retainer has a spring tension
acting in such a direction that a portion where an opening is
provided is pressed by a cover, and the spring tension serves to
make up for the change in positioning and strength between the
joined portions of the cover and a portion around the opening, and
can thereby maintain a predetermined level of the positioning
accuracy and adequate strength; therefore, the change caused by the
time-varying plastic materials in positioning and strength between
the joined portions of the cover (mount plate) and the tank body
can be prevented from lowering.
[0228] In a cover-mounting structure of a plastic container
according to the present invention, pump fittings are integrally
mounted in the cover, and thus no clearance remains between the
pump fittings and the cover; therefore, the hermetical sealing
performance between the cover (mount plate) and the tank body can
be improved.
[0229] In a cover-mounting structure of a plastic container
according to the present invention, a space to be allowed for
thermal contraction of plastic is provided between an outer inside
wall of an annularly arranged recess and an outer cylindrical end
face of the annular member, and thus when the thermal contraction
is completed after plastic molding, the outer cylindrical end face
of the annular member and outer inside wall of the annular recess
come into contact with each other. This allows the annular member
and the plastic container body to be firmly joined, serving to
maintain a good hermetical sealing performance of the opening, as
well as to improve positioning accuracy of the annular member.
[0230] In a cover-mounting structure of a plastic container
according to the present invention, the metal annular member is so
shaped as to be kept from obstructing the thermal contraction of
the plastic container, and thus bending or deformation due to local
internal shrinkage of thermally contracting plastic materials can
be prevented, so that the metal annular member can be slid smoothly
in the recess. Further, the metal annular member includes a
plurality of bolts provided protrusively at annularly arranged
positions along a peripheral edge of the opening, and thus a good
hermetical sealing performance of the opening can be maintained,
and positioning accuracy of the annular member can be improved.
[0231] In a cover-mounting structure of a plastic container
according to the present invention, the outer inside wall of the
recess and the outer cylindrical end face of at least one of the
annular member and the bolts are in contact with each other, and
thus no clearance remains between the annular member and the outer
inside wall of the recess, which allows the annular member and the
plastic container body to be firmly joined, serving to maintain a
good hermetical sealing performance of the opening, as well as to
improve positioning accuracy of the annular member.
[0232] In a cover-mounting structure of a plastic container
according to the present invention, the a bottom surface of the
space formed in the recess is in a position lower than bottom
surfaces of the annular member and the bolts, and thus the outer
cylindrical end faces of the bolts can be brought into close
contact with the inside wall of the recess, which serves to
maintain a good hermetical sealing performance of the opening, as
well as to improve positioning accuracy of the annular member and
the plastic container body.
[0233] In a cover-mounting structure of a plastic container
according to the present invention, a drainage passage is provided
in an external surface of the plastic container body to drain water
that tends to stay in or around interfaces between the recess and
the annular member and between the recess and the bolts, and thus
the interfaces between the bottom surfaces of the annular recess
and the annular member and spaces around the interfaces are allowed
to communicate by means of the drainage passage, which allows water
to drain to the outside, so as to prevent the formation of rust,
serving to maintain a good hermetical sealing performance of the
opening, as well as to improve positioning accuracy of the annular
member and the plastic container body.
[0234] In a cover-mounting structure of a plastic container
according to the present invention, the annular member is
insert-molded with a plastic material from which the plastic
container body is molded to form the plastic container body, and
thus the annular member and the plastic container body can be
mounted with improved accuracy, which provides effective
countermeasures when collision or the like occurs.
[0235] In a cover-mounting structure of a plastic container
according to the present invention, a through hole is provided to
allow a space formed on a side of the retainer facing the plastic
container body by fastening the retainer to the annular member to
communicate with outside, and thus when the plastic container is
submerged into a water tank during a submergence leak test, water
is allowed to flow through the through hole to fill up the space
for a short period of time. Accordingly, no extra time to wait is
required from submergence of the plastic container into the water
tank to introduction of pressure-regulated air, and therefore the
time for testing can be reduced. Moreover, the evolution of bubbles
derived from air in the space during the test can be prevented so
as not to make an erroneous identification as described above.
Consequently, the submergence leak test can be performed with
improved accuracy.
[0236] In a cover-mounting structure of a plastic container
according to the present invention, the through hole is provided in
the retainer, and assuming that the bottom of the plastic container
faces toward downward while the cover is located on its top, the
through hole allows the space to immediately communicate at its
top. Therefore, air that was in the space at the time of
submergence of the plastic container into the water tank is
discharged swiftly through the through hole by which the space
communicates at its top. As a result, in the submergence leak test,
the evolution of bubbles derived from air in the space during the
test can be prevented without fail, and the submergence leak test
can be performed with much more improved accuracy.
[0237] In a cover-mounting structure of a plastic container
according to the present invention, the through hole is provided
which allows the space to immediately communicate at its bottom,
and thus when the plastic container is raised from the water tank
after the submergence leak test has been carried out, water with
which the space is filled can be discharged swiftly through the
through hole. Accordingly, the process for drying the plastic
container after the test can be performed with increased ease, and
corrosion of constituent parts, which would result from residual
water after the test, can be prevented.
* * * * *