U.S. patent application number 12/032831 was filed with the patent office on 2008-08-28 for air bleeding pipe joint.
Invention is credited to Masahisa Isaji, Kazuhiro Kato, Akihiko Takahashi.
Application Number | 20080202596 12/032831 |
Document ID | / |
Family ID | 39714517 |
Filed Date | 2008-08-28 |
United States Patent
Application |
20080202596 |
Kind Code |
A1 |
Kato; Kazuhiro ; et
al. |
August 28, 2008 |
Air Bleeding Pipe Joint
Abstract
An air bleeding pipe joint has a pair of connection pipe
portions, a branch pipe portion having an air bleeding hole in an
inside thereof, a plug body, and an elastic annular sealing member
providing an air-tight seal between a female fitting surface of the
branch pipe portion and a male fitting surface of the plug body.
The plug body is removably mounted to the branch pipe portion in
threaded engagement therewith such that a seating surface of the
plug body seats on a seated surface of the branch pipe portion. An
air discharge path is provided on an upper end of the branch pipe
portion and/or the plug body with respect to a sealing position at
which the sealing member is disposed for discharging outwardly an
air that leaks upwardly through the sealing position.
Inventors: |
Kato; Kazuhiro; (Nagoya-shi,
JP) ; Takahashi; Akihiko; (Nagoya-shi, JP) ;
Isaji; Masahisa; (Niwa-gun, JP) |
Correspondence
Address: |
ANDRUS, SCEALES, STARKE & SAWALL, LLP
100 EAST WISCONSIN AVENUE, SUITE 1100
MILWAUKEE
WI
53202
US
|
Family ID: |
39714517 |
Appl. No.: |
12/032831 |
Filed: |
February 18, 2008 |
Current U.S.
Class: |
137/197 |
Current CPC
Class: |
Y10T 137/3084 20150401;
F16L 55/07 20130101; F01P 11/028 20130101; F16L 55/1108
20130101 |
Class at
Publication: |
137/197 |
International
Class: |
F24D 19/08 20060101
F24D019/08 |
Foreign Application Data
Date |
Code |
Application Number |
Feb 28, 2007 |
JP |
2007-049834 |
Claims
1. An air bleeding pipe joint, comprising: (a) a pair of connection
pipe portions inserted in and connected to a circulation pipeline
for an engine cooling water; (b) a branch pipe portion branched
from the connection pipe portions in upstanding condition and
having an air bleeding hole in an inside thereof, the air bleeding
hole including an internally threaded portion and a female fitting
surface under the internally threaded portion; (c) a plug body
removably mounted to the branch pipe portion for opening and
closing the air bleeding hole, the plug body having a large
diameter head portion of an upper end portion thereof with an under
surface defining a seating surface, an externally threaded portion,
and a male fitting surface under the externally threaded portion;
and (d) an elastic annular sealing member providing an air-tight
seal between the female fitting surface of the branch pipe portion
and the male fitting surface of the plug body mounted to the branch
pipe portion; the plug body being mounted to the branch pipe
portion with the externally threaded portion in threaded engagement
with the internally threaded portion such that the seating surface
of the head portion seats on a corresponding upwardly facing seated
surface of the branch pipe portion; wherein an air discharge path
is provided on an upper end of the branch pipe portion and/or the
plug body with respect to a sealing position at which the sealing
member is disposed, the air discharge path discharges outwardly an
air that leaks upwardly through the sealing position.
2. The air bleeding pipe joint as set forth in claim 1, wherein the
plug body has an overlapping surface that overlaps with an
overlapped surface of the branch pipe portion, the overlapping
surface and/or the overlapped surface is provided with a recessed
portion that allows an air to pass therethrough and defines at
least a part of the air discharge path.
3. The air bleeding pipe joint as set forth in claim 1, wherein the
plug body has an overlapping surface that overlaps with an
overlapped surface of the branch pipe portion, one of the
overlapping surface and the overlapped surface is provided with a
protruding portion protruding toward the other of the overlapping
surface and the overlapped surface for creating a gap between the
overlapping surface and the overlapped surface, and the gap defines
at least a part of the air discharge path.
4. The air bleeding pipe joint as set forth in claim 1, wherein the
plug body has an overlapping surface that overlaps with an
overlapped surface of the branch pipe portion, the overlapping
surface and/or the overlapped surface is formed into a roughened
surface having irregularities, and a gap in the roughened surface
defines at least a part of the air discharge path.
5. The air bleeding pipe joint as set forth in claim 2, wherein the
recessed portion is provided in the seating surface of the
overlapping surface and/or the seated surface of the overlapped
surface.
6. The air bleeding pipe joint as set forth in claim 3, wherein the
protruding portion is provided on the seating surface of the
overlapping surface or the seated surface of the overlapped
surface.
7. The air bleeding pipe joint as set forth in claim 4, wherein the
seating surface of the overlapping surface and/or the seated
surface of the overlapped surface is formed into the roughened
surface having the irregularities.
8. The air bleeding pipe joint as set forth in claim 1, wherein the
air discharge path is in a form of a recessed path or a
through-bore path that is provided in the upper end with respect to
the sealing position, the recessed path or the through-bore path
extends continuously from the sealing position and has an extremity
end open to outside.
9. The air bleeding pipe joint as set forth in claim 1, wherein the
plug body, and a joint body comprising the pair of the connection
pipe portions and the branch pipe portion are molded resin
products.
10. An air bleeding pipe joint, comprising: (a) a pair of
connection pipe portions inserted in and connected to a circulation
pipeline for an engine cooling water; (b) a branch pipe portion
branched from the connection pipe portions in upstanding condition
and having an air bleeding hole in an inside thereof; (c) a plug
body having a head portion of an upper end portion thereof with an
under surface defining a seating surface and adapted for opening
and closing the air bleeding hole, the plug body being removably
mounted to the branch pipe portion in threaded engagement therewith
such that the seating surface of the head portion seats on a
corresponding upwardly facing seated surface of the branch pipe
portion; and (d) an elastic annular sealing member providing an
air-tight seal between the plug body and the air bleeding hole;
wherein an air discharge path is provided between the seating
surface and the seated surface.
11. An air bleeding pipe joint, comprising: (a) a pair of
connection pipe portions inserted in and connected to a circulation
pipeline for an engine cooling water; (b) a branch pipe portion
branched from the connection pipe portions in upstanding condition
and having an air bleeding hole in an inside thereof; (c) a plug
body having a head portion of an upper end portion thereof with an
under surface defining a seating surface and adapted for opening
and closing the air bleeding hole, the plug body being removably
mounted to the branch pipe portion in threaded engagement therewith
such that the seating surface of the head portion seats on a
corresponding upwardly facing seated surface of the branch pipe
portion; and (d) an elastic annular sealing member providing an
air-tight seal between the plug body and the air bleeding hole;
wherein an air discharge path extends continuously from a sealing
position at which the sealing member is disposed and has an
extremity end open to outside.
Description
BACKGROUND OF THE INVENTION
[0001] 1. Field of the Invention
[0002] The present invention relates to an air bleeding pipe joint
connected to a circulation pipeline for an engine cooling water and
adapted for bleeding an air in the circulation pipeline.
[0003] 2. Description of Related Art
[0004] In a motor vehicle, when an engine cooling water is supplied
in a circulation pipeline for the engine cooling water, an air is
sometimes confined within the circulation pipeline, and as a
result, it is hard to inject the engine cooling water in a
radiator. As a countermeasure, an air bleeding portion has been
conventionally provided at a part of the circulation pipeline.
[0005] For example, Patent document 1 as below discloses a
technique of providing such air bleeding portion.
[0006] Further, Patent Document 2 as below also discloses such air
bleeding portion provided in a circulation pipeline for an engine
cooling water. According to the disclosure of Patent Document 2, an
air bleeding pipe joint as the air bleeding portion comprises a
pair of connection pipe portions inserted in and connected to the
circulation pipeline, a branch pipe portion branched from the
connection pipe portions and having an air bleeding hole in an
inside thereof, and a plug body removably mounted to the branch
pipe portion for opening and closing the air bleeding hole, and the
air bleeding pipe joint is provided in a circulation route for the
engine cooling water, namely at a part of the circulation pipeline
for the engine cooling water for bleeding or discharging outwardly
an air contained in the circulation pipeline by opening the air
bleeding hole.
[0007] FIG. 8 shows a specific example of the air bleeding pipe
joint as above.
[0008] In the Figure, reference numeral 200 indicates a heater hose
(a part of a pipeline for introducing a cooling water heated by an
engine to a heater core for heating a vehicle passenger
compartment) constituting a part of a circulation pipeline for the
engine cooling water, and reference numeral 202 indicates an air
bleeding pipe joint connected to these heater hoses 200.
[0009] The air bleeding pipe joint 202 is formed in a T-shape as
shown in FIG. 8B. The air bleeding pipe joint 202 has a pair of
connection pipe portions 204 and a branch pipe portion 206 branched
therefrom. The pair of the connection pipe portions 204 and the
branch pipe portion 206 comprise a joint body 207. These connection
pipe portions 204 are inserted in and connected to a pair of heater
hoses 200, and then fixed by hose clamps 208 thereto,
respectively.
[0010] The branch pipe portion 206 has an air bleeding hole 210 in
an inside thereof, and the air bleeding pipe joint 202 is adapted
for bleeding or discharging outwardly an air contained within the
circulation pipeline through the air bleeding hole 210.
[0011] Reference numeral 212 indicates a plug or plug body for
opening and closing the air bleeding hole 210. The plug 212 has an
externally threaded portion 214, the externally threaded portion
214 is screwed into an internally threaded portion 216 in an inner
surface of the branch pipe portion 206, and thereby the plug 212 is
attached to the branch pipe portion 206.
[0012] The plug 212 has a large diameter head portion 217 of
hexagonal shape, and the head portion 217 protrudes upwardly along
an axis of the branch pipe portion 206 and perpendicular to the
axis thereof with respect to the branch pipe portion 206.
[0013] FIG. 9 is an enlarged view showing a plug 212 that is
attached to a branch pipe portion 206, along with its vicinity
portion (an air bleeding pipe joint shown in FIG. 9 is different
from that shown in FIG. 8).
[0014] As shown in the Figure (FIG. 9), the plug 212 has a male
fitting surface 220 of a circular cross-section that is defined by
an outer peripheral surface of a lower portion of a shaft portion
218. The male fitting surface 220 includes an annular retaining
groove in which an elastic O-ring (annular sealing member) 222 is
retained. Thus configured male fitting surface 220 fits with or in
a corresponding female fitting surface 224 of the branch pipe
portion 206. An air-tight seal is provided by the O-ring 222
between the male fitting surface 220 and the female fitting surface
224.
[0015] Reference numeral 226 indicates a seating surface defined by
a lower surface of a head portion 217 of the plug 212. The plug 212
is screwed in the branch pipe portion 206 downwardly in the Figure
to such position that the seating surface 226 seats on a
corresponding upwardly facing seated surface 228 of the branch pipe
portion 206 in a tight-fit condition, and thereby is mounted to the
branch pipe portion 206.
[0016] By the way, for inspecting whether the O-ring 222 is
correctly attached in the air bleeding pipe joint 202, an
air-tightness test is conducted. In the air-tightness test, an air
bleeding hole 210 is closed by screwing the plug 217 in the branch
pipe portion 206.
[0017] However, when the plug 212 is tightly screwed in the branch
pipe portion 206, an externally threaded portion 214 of the plug
212 happens to tightly contact with an internally threaded portion
216 of the branch pipe portion 206, or the seating surface 226 of
the head portion 217 of the plug 212 happens to tightly contact
with the seated surface 228 of the branch pipe portion 206. In this
state, a seal is formed in a tight contact region, namely between
the externally threaded portion 214 and the internally threaded
portion 216, or between the seating surface 226 and the seated
surface 228, an air is not allowed to be bled outwardly through the
tight contact region. Therefore, even if the O-ring 222 fails to be
attached in the air bleeding pipe joint 212, in the air-tightness
test, the air bleeding pipe joint 212 happens to meet the test for
acceptable air-tightness.
[0018] In order to prevent such inconvenience, the air-tightness
test is conducted for the air bleeding pipe joint 202 with the plug
212 being not fully screwed in the branch pipe portion 206 (in
incompletely screwed condition), and after the test, the plug 212
is completely screwed to the branch pipe portion 206. However, in
this case, if the plug 212 fails to be finally screwed in the
branch pipe portion 206 after the test, the air bleeding pipe joint
202 is accidentally assembled to a pipeline of a motor vehicle with
the plug 212 being incompletely screwed in the branch pipe portion
206.
[0019] So, in this test method, there is a need for additional step
separately for preventing such inconvenience.
[0020] However, such additional step could be a complicating factor
in an assembly of an air bleeding pipe joint or an inspecting
procedure of the air bleeding pipe joint.
[0021] [Patent Document 1] JP-A-61-93225
[0022] [Patent Document 2] JP-A-2004-161163
[0023] Under the foregoing circumstances, it is an object of the
present invention to provide an air bleeding pipe joint that allows
an operator to detect a failure of attachment of an O-ring, even if
a plug is completely screwed in a branch pipe portion. In such air
bleeding pipe joint, there is no fear that the air bleeding pipe
joint is assembled to a pipeline of a motor vehicle without an
O-ring.
SUMMARY OF THE INVENTION
[0024] According to the present invention, there is provided a
novel air bleeding pipe joint. The air bleeding pipe joint
comprises (a) a pair of connection pipe portions inserted in and
connected to a circulation pipeline for an engine cooling water,
(b) a branch pipe portion branched from the connection pipe
portions in upstanding condition or upwardly standing condition and
having an air bleeding hole in an inside thereof, and (c) a plug or
plug body removably mounted to the branch pipe portion for opening
and closing the air bleeding hole. The air bleeding hole includes
an internally threaded portion and a female fitting surface under
the internally threaded portion. The plug body has a head portion
or a large diameter head portion of an upper end portion thereof
with an under surface defining a seating surface, an externally
threaded portion, and a male fitting surface under the externally
threaded portion. The air bleeding pipe joint further comprises (d)
an elastic annular sealing member providing an air-tight seal
between the female fitting surface of the branch pipe portion and
the male fitting surface of the plug body mounted to the branch
pipe portion. The plug body is mounted to the branch pipe portion
with the externally threaded portion in threaded engagement with
the internally threaded portion such that the seating surface of
the head portion seats on a corresponding upwardly facing seated
surface of the branch pipe portion. An air discharge path is
provided on an upper end of the branch pipe portion and/or the plug
body with respect to a sealing at which the sealing member is
disposed or a section to be sealed by the sealing member. The air
discharge path discharges outwardly an air that leaks upwardly
through the sealing position or the section. The plug body is
allowed for repeated removal from and reattachment to the branch
pipe portion.
[0025] According to one aspect of the present invention, the plug
body has an overlapping surface that overlaps with an overlapped
surface of the branch pipe portion, the overlapping surface and/or
the overlapped surface is provided with a recessed portion that
allows an air to pass therethrough and defines at least a part of
the air discharge path. For example, the seating surface of the
overlapping surface of the plug body and/or the seated surface of
the overlapped surface of the branch pipe portion is provided with
the recessed portion.
[0026] According to one aspect of the present invention, the plug
body has an overlapping surface that overlaps with an overlapped
surface of the branch pipe portion, one of the overlapping surface
and the overlapped surface is provided with a protruding portion
protruding toward the other of the overlapping surface and the
overlapped surface for creating a gap between the overlapping
surface and the overlapped surface, and the gap defines at least a
part of the air discharge path. For example, one of the seating
surface of the overlapping surface of the plug body and the seated
surface of the overlapped surface of the branch pipe portion is
provided with the protruding portion.
[0027] According to one aspect of the present invention, the plug
body has an overlapping surface that overlaps with an overlapped
surface of the branch pipe portion, the overlapping surface and/or
the overlapped surface is formed into a roughened surface having
irregularities or protuberances, and the gap in the roughened
surface defines at least a part of the air discharge path. For
example, the seating surface of the overlapping surface of the plug
body and/or the seated surface of the overlapped surface of the
branch pipe portion is formed into the roughened surface having the
irregularities or the protuberance.
[0028] According to one aspect of the present invention, a recessed
path or a through-bore path is provided in an upper end of the
branch pipe portion and/or the plug body with respect to the
sealing position, the recessed path or the through-bore path
extends continuously from the sealing position and has an extremity
end open to outside, and the recessed path or the through-bore path
serves as the air discharge path. The recessed path or the
through-bore path extends from the sealing position to the
extremity end.
[0029] According to one aspect of the present invention, the plug
body, a joint body comprising the pair of the connection pipe
portions and the branch pipe portion are molded resin products.
[0030] According to the present invention, in an air bleeding pipe
joint comprising (a) a pair of connection pipe portions inserted in
and connected to a circulation pipeline for an engine cooling
water, (b) a branch pipe portion branched from the connection pipe
portions in upstanding condition and having an air bleeding hole in
an inside thereof, (c) a plug body for opening and closing the air
bleeding hole which has a head portion of an upper end portion
thereof with an under surface defining a seating surface and is
removably mounted to the branch pipe portion in threaded engagement
therewith such that the seating surface of the head portion seats
on a corresponding upwardly facing seated surface of the branch
pipe portion, and (d) an elastic annular sealing member providing
an air-tight seal between the plug body and the air bleeding hole,
an air discharge path is provided between the seating surface and
the seated surface.
[0031] According to the present invention, in an air bleeding pipe
joint comprising (a) a pair of connection pipe portions inserted in
and connected to a circulation pipeline for an engine cooling
water, (b) a branch pipe portion branched from the connection pipe
portions in upstanding condition and having an air bleeding hole in
an inside thereof, (c) a plug body for opening and closing the air
bleeding hole which has a head portion of an upper end portion
thereof with an under surface defining a seating surface and is
removably mounted to the branch pipe portion in threaded engagement
therewith such that the seating surface of the head portion seats
on a corresponding upwardly facing seated surface of the branch
pipe portion, and (d) an elastic annular sealing member providing
an air-tight seal between the plug body and the air bleeding hole,
an air discharge path extends continuously from a sealing position
at which the sealing member is disposed or a section to be sealed
by the sealing member and has an extremity end open to outside.
[0032] As stated above, according to the present invention, an air
discharge path is provided on an upper end with respect to a
sealing position at which a sealing member is disposed or the
section to be sealed by the sealing member, for discharging
outwardly an air that leaks upwardly through the sealing position
or the section. Therefore, when an air-tightness test is conducted
for an air bleeding pipe joint in which the sealing member fails to
be attached, an air can be positively discharged outwardly through
the air discharge path.
[0033] On the other hand, when the air-tightness test is conducted
for the air bleeding pipe joint in which the sealing member is
correctly attached, an air is not discharged or leaked outwardly
since an air-tight seal is positively provided at the sealing
position of the sealing member or the section to be sealed by the
sealing member.
[0034] Thus, according to the present invention, it can be
positively detected whether the sealing member is attached in the
air bleeding pipe joint, by conducting the air-tightness test.
[0035] As described above, in the past, in order to verify
attachment of a sealing member, an air-tightness test is conducted
for an air bleeding pipe joint with a plug body being not fully
screwed in a branch pipe portion. So, there is a need for adding a
step of screwing the plug body completely in the branch pipe
portion after the air-tightness test in an assembling procedure or
an inspection procedure of the air bleeding pipe joint. According
to the present invention, the need for this bothersome step can be
eliminated.
[0036] In the present invention, the plug body may have an
overlapping surface that overlaps with an overlapped surface of the
branch pipe portion. One of the overlapping surface and the
overlapped surface may be provided with a recessed portion for
allowing an air to pass therethrough, and the recessed portion may
define at least a part of the air discharge path.
[0037] Or, the other of the overlapping surface and the overlapped
surface may be also provided with the recessed portion for allowing
an air to pass therethrough.
[0038] In the present invention, one of the overlapping surface and
the overlapped surface may be provided with a protruding portion
protruding toward the other of the overlapping surface and the
overlapped surface for creating a gap between the overlapping
surface and the overlapped surface, and the gap may define at least
a part of the air discharge path.
[0039] In this case, the other of the overlapping surface and the
overlapped surface may be also provided with a protruding portion
protruding toward the one of the overlapping surface and the
overlapped surface.
[0040] In the present invention, the overlapping surface and/or the
overlapped surface may be formed into a roughened surface having
irregularities or protuberances, and a gap in the roughened surface
may define at least a part of the air discharge path.
[0041] Here, the roughened surface means a surface having a
roughness of 50 .mu.m to 500 .mu.m in terms of Rz specified in JIS
B0601.
[0042] As stated above, in a conventional air bleeding pipe joint,
when the plug body is tightly screwed in the branch pipe portion,
there is a fear that the seating surface of the plug body tightly
contacts with the seated surface of the branch pipe portion, a seal
is formed between the seating surface and the seated surface, and
an air that leaks through the sealing position is confined
internally.
[0043] However, when the recessed portion is provided in the
seating surface of the overlapping surface and/or the seated
surface of the overlapped surface for allowing an air to pass
through the recessed portion, it can be prevented that the air
bleeding pipe joint without the sealing member happens to meet the
test for acceptable air-tightness since an air that leaks through
the sealing position is confined internally.
[0044] When the above protruding portion is provided on the seating
surface of the overlapping surface and/or the seated surface of the
overlapped surface, this protruding portion can produce the same
effect as the recessed portion stated above.
[0045] Or, the seating surface and/or the seated surface may be
formed into the roughened surface having the irregularities or the
protuberances. This configuration also can produce the same effect
as the recessed portion stated above.
[0046] Here, the roughened surface means a surface having a
roughness of 50 .mu.m to 500 .mu.m in terms of Rz specified in JIS
B0601.
[0047] Or, a recessed path or a through-bore path may be provided
in the upper end with respect to the sealing position or the
section to be sealed. The recessed path or the through-bore path
extends continuously from the sealing position or the section to be
sealed and has an extremity end open to outside. The recessed path
or the through-bore path may serve as the air discharge path. In
this configuration, even if a seal is formed between the
overlapping surface of the plug body and the overlapped surface of
the branch pipe portion, an air that leaks through the sealing
position or the section to be sealed can be positively discharged
outwardly through the air discharge path defined by the recessed
path or the through-bore path.
[0048] The present invention produces a great effect in particular
in the case that the plug body, a joint body comprising a pair of
the connection pipe portions and the branch pipe portion are molded
resin products.
[0049] The reason is that in the air bleeding pipe joint of the
molded resin product, the overlapping surface of the plug body
tends to tightly contact with the overlapped surface of the branch
pipe portion and an air-tight seal is easily formed between the
overlapping surface and the overlapped surface, resulting that a
air is easily confined internally by a tightly contact region
therebetween.
[0050] Now, a description will be given in detail of an embodiment
in accordance with the present invention on the basis of the
accompanying drawings.
BRIEF DESCRIPTION OF THE DRAWINGS
[0051] FIG. 1 is an explanatory view showing a position at which an
air bleeding pipe joint according to one embodiment of the present
invention is applied.
[0052] FIG. 2A is a perspective exploded view of the air bleeding
pipe joint of FIG. 1.
[0053] FIG. 2B is a perspective view of the air bleeding pipe joint
of FIG. 1 which is assembled.
[0054] FIG. 3A is an exploded, side-sectional view of the air
bleeding pipe joint of FIG. 1.
[0055] FIG. 3B is a side-sectional view of the air bleeding pipe
joint of FIG. 1 which is assembled.
[0056] FIG. 4A is a perspective view showing that a protrusion is
provided on a seated surface of a branch pipe portion.
[0057] FIG. 4B is a perspective view showing that another
protrusion is provided on the seated surface of the branch pipe
portion.
[0058] FIG. 4C is a perspective view showing that yet another
protrusion is provided on the seated surface of the branch pipe
portion.
[0059] FIG. 4D is a perspective view showing that a recessed
portion is provided on the seated surface of the branch pipe
portion.
[0060] FIG. 4E is a perspective view showing that another recessed
portion is provided on the seated surface of the branch pipe
portion.
[0061] FIG. 5A is a perspective view showing that a seating surface
of a plug body is formed into a roughened surface.
[0062] FIG. 5B is a perspective view showing that the seating
surface of the plug body and the seated surface of the branch pipe
portion are formed into the roughened surfaces.
[0063] FIG. 6A is a perspective view showing that the protrusion is
provided on the seating surface of the plug body.
[0064] FIG. 6B is a perspective view showing that the another
protrusion is provided on the seating surface of the plug body.
[0065] FIG. 6C is a perspective view showing that the yet another
protrusion is provided on the seating surface of the plug body.
[0066] FIG. 6D is a perspective view showing that the recessed
portion is provided on the seating surface of the plug body.
[0067] FIG. 6E is a perspective view showing that the another
recessed portion is provided on the seating surface of the plug
body.
[0068] FIG. 7 is a sectional view showing that a through-bore path
is formed in a plug body.
[0069] FIGS. 8A to 8C are views showing a conventional air bleeding
pipe joint.
[0070] FIG. 9 is a view showing a relevant part of another
conventional air bleeding pipe joint.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS
[0071] With reference to FIG. 1, reference numeral 10 indicates a
circulation pipeline for an engine cooling water, reference numeral
10-1 indicates a radiator-end pipeline communicating between an
engine 12 and a radiator 14, and reference numeral 10-2 indicates a
heater-end pipeline communicating between the engine 12 and a
heater core 16 for heating a vehicle compartment.
[0072] In the Figure, reference numeral 18-1 indicates a upper
radiator hose made of rubber, constituting a part of the
circulation pipeline 10, specifically a part of the radiator-end
pipeline 10-1, and reference numeral 18-2 indicates a lower
radiator hose.
[0073] Reference numeral 20-1 indicates an upper heater hose made
of rubber, constituting similarly a part of the circulation
pipeline 10, specifically a part of the heater-end pipeline 10-2,
and reference numeral 20-2 indicates a lower heater hose.
[0074] Further, reference numeral 22 indicates a water pump, and
reference numeral 23 indicates a thermo valve with a thermostat
function.
[0075] As seen in FIG. 1, an air bleeding pipe joint 24 of the
present embodiment is connected between the upper heater hoses
(hereinafter, simply referred to as heater hoses) 20-1, 20-1.
[0076] FIGS. 2 and 3 show a specific arrangement of the air
bleeding pipe joint 24.
[0077] The air bleeding pipe joint 24 is made of resin, and has a
T-shape as a whole. The air bleeding pipe joint 24 has a pair of
connection pipe portions 26, and a branch pipe portion 28 uprising
or upstanding from the connection pipe portions 26, perpendicular
to the connection pipe portions 26. The connecting pipe portions 26
made of resin and the branch pipe portion 28 made of resin comprise
a resin joint body.
[0078] Each of the pair of the connection pipe portions 26 is
inserted in and connected to the heater hose 20-1. The connection
pipe portion 26 is provided with an annular projecting portion that
defines a bulge portion 30 on an outer peripheral surface of an
extremity portion thereof.
[0079] The branch pipe portion 28 has an air bleeding hole 32 in an
inside thereof. An air contained in the circulation pipeline 10 is
discharged or bled outwardly through the air bleeding hole 32.
[0080] The branch pipe portion 28 has a female fitting surface 34
of circular cross-section defined by a lower portion of an inner
surface thereof, and an internally threaded portion or female
threaded portion 36 above the female fitting surface 34.
[0081] An upper end surface of the branch pipe portion 28 serves as
an upwardly facing seated surface 38 on which a seating surface 48
of a plug 40 (to be described later) seats.
[0082] Reference numeral 40 indicates a plug or a plug body made of
resin for closing or opening the air bleeding hole 32. The plug 40
is removably and threadably mounted to the branch pipe portion 28.
The plug 40 has a shaft portion 42 of circular cross-section, and a
head portion 44 of a disc shape on an upper end portion of the
shaft portion 42. The head portion 44 has a diameter larger than
the shaft portion 42.
[0083] The head portion 44 here has ribs 46 that are
circumferentially spaced apart at a uniform pitch on an outer
peripheral surface of the head portion 44 throughout an entire
circumference of the head portion 44.
[0084] In the present embodiment, the head portion 44 also serves
as a knob for rotating operation of the plug body 40. The above
ribs 46 serve a slip-resistant function during rotating operation
of the head portion 44.
[0085] Meanwhile, an engaging recessed portion 47 is formed at a
center in an upper surface of the head portion 44. The engaging
recessed portion 47 has a hexagonal planar shape. The head portion
44 can be rotated by a tool such as a hexagonal wrench that is
adapted to fit and engage in the engaging recessed portion 47.
[0086] An under surface of the head portion 44 defines a flat
seating surface 48. The seating surface 48 seats on a seated
surface 38 that is defined by an upper end surface or top surface
of the above branch pipe portion 28.
[0087] Here, the seating surface 48 and the seated surface 38 serve
as or define overlapping surfaces that overlap each other in a
vertical direction, an up-and-down direction or an axial direction
of the branch pipe portion 28. Or, the seating surface 48 serves as
or defines an overlapping surface, and the seated surface 38 serves
as or defines an overlapped surface.
[0088] An outer peripheral surface of a lower portion of the shaft
portion 42 of the plug 40 is formed into a male fitting surface 49
of circular cross-section. An annular O-ring groove 50 is formed in
the male fitting surface 49, and an elastic O-ring 52 of circular
ring shape is retained in the annular O-ring groove 50.
[0089] And, the shaft portion 42 has an externally threaded portion
or male threaded portion 54 that is defined by an outer peripheral
surface thereof, above the O-ring or sealing member 52.
[0090] Here, the externally threaded portion 54 and the internally
threaded portion 36 may serve as or define overlapping surfaces
that overlap each other, or the externally threaded portion 54 may
serve as or define an overlapping surface, and the internally
threaded portion 36 may serve as or define an overlapped
surface.
[0091] When the externally threaded portion 54 of the plug or plug
body 40 is screwed and tightened downwardly in the internally
threaded portion 36 of the branch pipe portion 28, the male fitting
surface 49 of the shaft portion 42 fits with the female fitting
surface 34 of the branch pipe portion 28 via the O-ring 52, and an
air-tight seal is formed between the male fitting surface 49 and
the female fitting surface 34 by the O-ring 52 as shown in FIG.
3B.
[0092] And, at that time, the seating surface 48 defined by the
under surface of the head portion 44 seats on the seated surface 38
defined by the upper end surface of the branch pipe portion 28.
[0093] In the present embodiment, the seated surface 38 of the
branch pipe portion 28 is formed entirely into a roughened surface
38a having fine irregularities or fine protuberances.
[0094] Here, the roughened surface 38a has a roughness or roughness
degree of 50 .mu.m in terms of Rz (JIS B0601). This also applies to
roughened surfaces 36a, 39a, 54a to be described later.
[0095] As a result, in the present embodiment, as shown in FIG. 3B,
even when the plug 40 is fully screwed and tightened with respect
to the branch pipe portion 28, tight contact between the seating
surface 48 defined by the under surface of the head portion 44 of
the plug 40 and the seated surface 38 of the branch pipe portion 28
is prevented by the roughened surface 38a. A gap is created between
the seating surface 48 and the seated surface 38 by the fine
irregularities of the roughened surface 38a.
[0096] In case that the O-ring 52 fails to be attached in the
O-ring groove 50, namely at a sealing position, an air leaks from
the sealing position. In this case, the gap serves as an air
discharge path for discharging or exhausting to the outside the air
that leaks through the sealing position.
[0097] In a conventional air bleeding pipe joint, when a plug is
fully screwed and strongly tightened, a seating surface of a large
diameter head portion tightly and closely contacts with a seated
surface of a branch pipe portion. This close contact relation
therebetween sometimes does not allow an air leaking through the
sealing position to be bled to the outside, and confines the air
internally. However, according to the present embodiment, close
contact between the seating surface 48 and the seated surface 38 is
prevented and an air discharge path is formed therebetween.
Therefore, in an air-tightness inspection for the air bleeding pipe
joint 24, when no air leaks, the O-ring 52 is positively attached
correctly, and when an air leaks, the O-ring 52 positively fails to
be attached. So, it can be positively detected and determined
whether the O-ring 52 is attached correctly.
[0098] Next, FIG. 4A shows another embodiment of the present
invention. In the embodiment of FIG. 4A, protrusions 56 are
provided at a plurality of positions spaced circumferentially, on
the seated surface 38 (the seated surface 38 in FIG. 2A without any
fine irregularities) of the branch pipe portion 28. Each of the
protrusions 56 protrudes upwardly, toward the seating surface 48 of
the plug or plug body 40.
[0099] Here, each of the protrusions 56 has a conical shape, and
the protrusions 56 are arranged at four positions circumferentially
spaced by 90.degree..
[0100] However, the number of the protrusion 56 may be varied and
the shape of the protrusion 56 may be varied.
[0101] FIG. 4B shows a protrusion 58 that has a shape different
from the protrusion 56 of FIG. 4A. The protrusion 58 as shown in
FIG. 4B has a square cross-section, and extends radially, through
an entire width of the seated surface 38 (the seated surface 38 in
FIG. 2A without any fine irregularities) so as to cross the seated
surface 38.
[0102] FIG. 4C shows further another protrusion 59 that has a
triangle cross-section, and extends radially, through the entire
width of the seated surface 38 (the seated surface 38 in FIG. 2A
without any fine irregularities) so as to cross the seated surface
38.
[0103] In the protrusion 56, 58, 59 as shown in FIGS. 4A, 4B and
4C, a protruding height of the protrusion 56, 58, 59 is 0.3 mm to
1.0 mm here. However, the protruding height may be changed
properly.
[0104] As stated, by providing the protrusion 56, 58, 59 on the
seated surface 38, the gap is created between the seating surface
48 of the plug 40 and the seated surface 38 of the branch pipe
portion 28 even when the plug 40 is fully screwed and tightened in
the branch pipe portion 28, and the gap serves as an air discharge
path for discharging outwardly an air that leaks through the
sealing position.
[0105] So, also in this case, in an air-tightness inspection for
the air bleeding pipe joint 24, an air positively leaks when the
O-ring 52 fails to be attached, thereby it can be positively
detected that the O-ring 52 fails to be attached.
[0106] On the other hand, FIGS. 4D and 4E show cases where the
seated surface 38 (the seated surface 38 in FIG. 2A without any
fine irregularities) is provided with a recess (recessed portion)
60, 61 instead of the protrusion 58, 59. The recess 60, 61 extends
radially throughout an entire width of the seated surface 38 so as
to cross the seated surface 38.
[0107] The recess 60 shown in FIG. 4D has a triangle cross-section,
while the recess 61 shown in FIG. 4E has a square cross-section.
Needless to say, the recess 60, 61 may have various cross-sectional
shapes.
[0108] In the examples or embodiments shown in FIGS. 4D and 4E, the
recess 60, 61 serves as an air discharge path for discharging
outwardly an air leaking through the sealing position. Therefore,
also in this case, in an air-tightness test, when the O-ring 52
fails to be attached, an air that leaks through the sealing
position is bled positively outwardly.
[0109] So, it can be surely verified whether the O-ring 52 is
attached by conducting the air-tightness test.
[0110] In the above embodiments, the seated surface 38 of the
branch pipe portion 28 is formed into the roughened surface 38a, or
the seated surface 38 of the branch pipe portion 28 is formed with
the protrusion 56, 58, 59, or the recess 60, 61. On the other hand,
the seating surface 48 defined by the under surface of the head
portion 44 of the plug 40 may be formed into the roughened surface
or may be formed with the protrusion 56, 58, 59, or the recess 60,
61.
[0111] FIG. 5 shows the case that the seating surface 48 is formed
into a roughened surface 39a (FIG. 5A) and the case that the seated
surface 38 and the seating surface 48 are formed into roughened
surfaces 38a, 39a (FIG. 5B) as an example. The roughened surface
39a may have the same irregularities or protuberances as the
roughened surface 38a.
[0112] Needless to say, the protrusion 56, 58, 59 or the recess 60,
61 as stated above may be formed on or in the seating surface 48
(refer to FIGS. 6A to 6E).
[0113] When an air is allowed to pass through between the
externally threaded portion 54 and the internally threaded portion
36 in the air bleeding pipe joint 24, the externally threaded
portion 54 and the internally threaded portion 36 are not
necessarily required to be formed into the roughened surfaces.
However, in a conventional air bleeding pipe joint, when a plug is
fully screwed and tightened, an externally threaded portion of the
plug may closely contact with an internally threaded portion of a
branch pipe portion to form a seal therebetween, an air that leaks
through the sealing position (an annular sealing groove) may be
confined internally, and may be prevented from being bled
outwardly. So, in this case, the air discharge path may be secured
between the threaded portions by forming one or both of the
externally threaded portion 54 and the internally threaded portion
36 into the roughened surface or roughened surfaces (54a, 36a) in
the same form as the roughened surface 38a. In FIG. 5B and FIG. 6,
the externally threaded portion 54 and the internal threaded
portion 36 are formed into the roughened surfaces 54a, 36a, and
define a part of an air discharge path (in FIGS. 6B to 6E, the
branch pipe portion 28 of FIG. 6A is omitted).
[0114] Or, an air discharge path may be secured also by forming the
recess 60, 61, etc. as stated above at least in one of the
externally threaded portion 54 and the internally threaded portion
36.
[0115] FIG. 7 shows yet another embodiment according to the present
invention.
[0116] In this embodiment, a through-bore path 62 with its
extremity open to the outside is provided in a portion of the plug
40 above the sealing position. The through-bore path 62 extends
continuously from the sealing position or a sealing section to be
sealed by the O-ring 52, specifically from the O-ring groove 50. In
this arrangement, even when an air is prevented from being bled by
close contact between the seating surface 48 and the seated surface
38, by close contact between the externally threaded portion 54 and
the internally threaded portion 36, or by close contact between the
seating surface 48 and the seated surface 38 and tight contact
between the externally threaded portion 54 and the internally
threaded portion 36, an advantage may be obtained that an air
leaking through the sealing position can be positively bled
outwardly.
[0117] Here, the through-bore path 62 comprises a bore formed in
the plug 40 and a recess between the seating surface 48 and the
seated surface 38 or in the seating surface 48. The bore extends
from the O-ring groove 50 upwardly in a vertical direction, and the
recess extends in a radial direction.
[0118] However, the through-bore path 62 may take various other
routes and different shapes. As the case may be, such through-bore
path 62 may take a form of a through-bore extending through the
shaft portion 42 of the plug 40 and the head portion 44, or
extending through the branch pipe portion 28.
[0119] Although the preferred embodiment has been described, this
is one of examples of the present invention. The present invention
may be constructed and embodied in various configurations and modes
within the scope of the present invention.
* * * * *