U.S. patent application number 11/079112 was filed with the patent office on 2005-10-20 for mechanical seal device.
This patent application is currently assigned to EAGLE INDUSTRY CO., LTD.. Invention is credited to Kametaka, Koji, Kiryu, Kenji.
Application Number | 20050230923 11/079112 |
Document ID | / |
Family ID | 34836590 |
Filed Date | 2005-10-20 |
United States Patent
Application |
20050230923 |
Kind Code |
A1 |
Kametaka, Koji ; et
al. |
October 20, 2005 |
Mechanical seal device
Abstract
A primary technical goal of a mechanical seal device of the
present invention is to decrease assembly cost thereof as well as
machining cost thereof and to prevent wear of seal surfaces by
preventing occurrence of squealing noises of the seal surfaces. The
mechanical seal device comprises a first seal ring which is one of
a pair of seal rings and disposes an engagement portion at the
outer circumferential surface, a retainer ring which has a first
support portion supporting an inner diameter surface of the first
seal ring and a second support portion engaging the engagement
portion and is fixed with either a seal housing or a shaft, and a
gasket which joins the retainer ring and the first seal ring in a
sealing manner, wherein an engagement clearance (C) formed in a
rotational direction between the engagement portion and the second
support portion is within 0.5 mm.
Inventors: |
Kametaka, Koji; (Tokyo,
JP) ; Kiryu, Kenji; (Tokyo, JP) |
Correspondence
Address: |
ARENT FOX PLLC
1050 CONNECTICUT AVENUE, N.W.
SUITE 400
WASHINGTON
DC
20036
US
|
Assignee: |
EAGLE INDUSTRY CO., LTD.
|
Family ID: |
34836590 |
Appl. No.: |
11/079112 |
Filed: |
March 15, 2005 |
Current U.S.
Class: |
277/602 |
Current CPC
Class: |
Y10T 29/49945 20150115;
Y10T 29/4987 20150115; Y10T 29/49297 20150115; Y10T 29/49872
20150115; F16J 15/348 20130101; F16J 15/38 20130101; Y10T 29/49952
20150115; F16J 15/3476 20130101 |
Class at
Publication: |
277/602 |
International
Class: |
F16L 003/04 |
Foreign Application Data
Date |
Code |
Application Number |
Mar 19, 2004 |
JP |
2004-079620 |
Claims
What is claimed is:
1. A mechanical seal device for providing a seal between a bore
disposed in a seal housing and a shaft extending through said bore
by means of a pair of seal rings, said mechanical seal device
comprising: a) a first seal ring being one of a pair of said seal
rings and disposing an engagement portion at the outer
circumferential surface; b) a retainer ring having a first support
portion and a second support portion and being fixed with either
said seal housing or said shaft, said first support portion
supporting said first seal ring, said second support portion
engaging said engagement portion to be locked with each other in a
rotational direction; and c) a gasket being made of a rubber-like
elastic material and being disposed between said first support
portion of said retainer ring and said first seal ring and joining
said first support portion and said first seal ring, said gasket
being in a fixed contact relation with said first support portion
and said first seal ring, wherein an engagement clearance (C)
formed in a rotational direction between an engagement end portion
of said second support portion and an engagement wall of said
engagement portion is within 0.5 mm.
2. A mechanical seal device as claimed in claim 1 wherein said
engagement portion is arranged to be an axially extending
engagement slot and said second support portion are arranged to be
a cantilever beam which is inserted into said engagement
portion.
3. A mechanical seal device as claimed in claim 2 wherein a bottom
surface of said engagement portion is in contact with the inner
circumferential surface of said second support portion with a
dimensional interference between said second support portion and
said bottom surface, wherein said dimensional interference is in a
range of from 0 to 0.25 mm.
4. A mechanical seal device as claimed in claim 1 wherein a
plurality of said engagement portions of said first seal ring
engage a plurality of said second support portion of said retainer
ring along the circumferential surface, wherein said second support
portion and said bottom surface of said engagement portion are
arranged in non-contact state with each other.
5. A mechanical seal device as claimed in claim 1 wherein said
second support portions are disposed in an outer ring and
cantilever beams formed in said outer ring by slitting in the axial
direction are bent towards radially inward direction of said
engagement portions, said outer ring surrounding said first seal
ring.
Description
BACKGROUND OF THE INVENTION
[0001] 1. Field of the Invention
[0002] The present invention relates generally to a mechanical seal
device which not only is economical in manufacture cost and
assembly cost of parts thereof but also prevents squealing noises
and wear of sliding surfaces thereof. More particularly, the
invention relates to a mechanical seal device in which a certain
arrangement of the assembly parts thereof materializes prevention
of squealing and wear at the seal surface of a seal ring during
relative sliding movement as well as improvement of durability of a
gasket supporting the seal ring.
[0003] 2. Description of the Related Art
[0004] A seal ring to provide a seal against a sealed fluid, in
general, is made of a hard material such as silicon carbide in
order to prevent wear of seal surface thereof. A gasket being made
of a rubber-like elastic material is typically employed in order to
effect a seal at the installation surface wherein the seal ring is
retained as well as to provide a support for the seal ring. The
support provided by the gasket, however, suffers from a torsional
deformation to circumferential direction thereof which is caused by
a rotary torque acted on the seal surface. Although the seal ring
is fixed by means of a support portion of a retainer ring in order
to circumvent the torsional deformation, engagement arrangement
between the retainer ring and the seal ring becomes complicated
because the seal ring needs to fixate engagement portion thereof
with the retainer ring while simultaneously being fitted to the
gasket. Such a complex arrangement in the engagement arrangement
causes various difficulties against the gasket as well as the seal
surface of the seal ring.
[0005] FIG. 4 displays a mechanical seal device 211 as a first
prior art related to the present invention. The figure shows a half
portion of a cross-sectional view of the mechanical seal device
211. In FIG. 4, a rotary seal ring 202 having a seal surface 202A
is fitted at inner circumferential surface thereof with a cup
gasket 204. The cup gasket 204 then is fitted with a mount portion
203D of a sleeve member 203. Outer circumferential surface of the
rotary seal ring 202 disposes two or four equally spaced slot
portions 202G, and each slot portion 202G forms an engagement flat
surface 202T at the bottom of the slot. The mount portion 203D
disposes a holding plate 203A which protrudes therefrom. The
holding plate 203A is inserted into the slot portion 202G with a
play against the side walls of the slot portion 202G. One rotary
seal portion 201 in which the rotary seal ring 202 is fitted with
the cup gasket 204 and the cup gasket 204 then is mounted onto the
sleeve member 203 is arranged such that a fixing portion 203C of
the rotary seal portion 201 can be fittingly fixed to a rotary
shaft at inner diameter surface thereof.
[0006] Stationary seal ring 212, on the other hand, is fittingly
fixed with a bellows member 214. Outer diameter portions of both
distal end portions of the bellows member 214 fittingly mate with a
first retainer portion 213A and a second retainer portion 213B,
respectively, which effectively anchor the bellows member 214 at
distal end portions thereof. A cartridge member 215 is fixed to a
housing at one end thereof while other end thereof is fitted with
the inner diameter surface of the stationary seal ring 212 in a
slidable manner. In addition, a coil spring 219 is disposed between
the first retainer portion 213A and the cartridge member 215. The
spring 219 resiliently urges the stationary seal ring 212 against
the rotary seal ring 202. This effects a seal against the sealed
fluid by bringing an opposing seal surface 212A of the stationary
seal ring 212 into seal-tight contact with the seal surface 202A of
the rotary seal ring 202.
[0007] As illustrated in FIG. 4 and FIG. 5 including the
aforementioned arrangement, a plurality of holding plates 203A
which are disposed at the outer perimeter of the mount portions
203D are inserted into the respective slot portions 202G which are
formed at the outer circumference of the rotary seal ring 202. It,
however, is very difficult to make the width B of the holding plate
203A same as the width A of the mating slot portion 202G under
current fabrication technologies due to presence of machining
tolerance. Even if it is assumed that the width A and width B have
exactly the same dimension, there remains another problem in that
it is almost impossible to exactly align the locations of a
plurality of holding plates 203A with those of the corresponding
slot portions 202G which are spaced apart along the circumference.
Therefore the width B of the holding plate 203A needs to be made
smaller than the width A of the slot portion 202G so that the
holding plate 203A leaves a gap to sides thereof for an easy
installation. With such an arrangement, the holding plates 203A can
be fitted to respective slot portions 202G. Furthermore, the rotary
seal ring 202 is fixedly retained by the cup gasket 204 which is
elastically deformable. When the seal surface 202A of the rotary
seal ring 202 is subjected to a sliding movement relative to the
opposing seal surface 212A of the stationary seal ring 212, a
frictional force during the sliding movement generates a torque
which will in turn induce a reciprocal torsion to the cup gasket
204 which connects the sleeve member 203 and the rotary seal ring
202 because of the clearance between the holding plate 203A and the
slot portion 202G. This forces the seal surface 202A to repeat a
stick-and-slip motion during the operation, which causes squealing
noises at the relatively sliding seal surfaces 202A, 212A. To make
things worse, the squealing and abnormal slip motion will lead to a
rapid wear of the relatively sliding seal surfaces 202A, 212A and
the cup gasket 204 will not last long as expected due to the
reciprocal torque load. As a result, the mechanical seal device 211
will lose seal ability and durability thereof.
[0008] There is another mechanical seal device 111 shown in FIG. 6
as a second prior art relative to the present invention. Gross
arrangement of the mechanical seal device 111 is more or less
similar to that in FIG. 4, hence not shown. The overall arrangement
will be described according to FIG. 6 and FIG. 5. What makes the
mechanical seal device 111 in FIG. 6 different from the mechanical
seal device 211 in FIG. 5 resides in a seal ring 102 and a sleeve's
mount portion 103D, which will be explained in detail by using FIG.
6. As shown in FIG. 6, the rotary seal ring 102 forms a pair of
engagement flat surfaces 102B, 102B at two symmetrical locations,
top and bottom, of the outer perimeter surface. And the inner
circumferential surface of the rotary seal ring 102 is fitted to
the outer diameter surface of an annular cup gasket 104. The cup
gasket 104 serves as a joint member to fittingly fixate the rotary
seal ring 102 to an annular mount portion 103D of the sleeve. FIG.
6 also shows that the mount portion 103D retains a pair of flat
holding plates 103A, 103A formed on the outer perimeter of the
sleeve. The holding plates 103A, 103A are arranged in such a manner
that the plates are kept in close contact state with the engagement
flat surfaces 102B, 102B of the seal ring 102.
[0009] Arrangement of opposing members relative to the rotary seal
ring 102 is omitted in FIG. 6, thus referring to FIG. 4. Disposed
in opposite to the rotary seal ring 102, as shown in FIG. 4, is a
stationary seal ring 212. The stationary seal ring 212 comes into
contact with a bellows member 214 which is disposed between the
stationary seal ring 212 and a cartridge member 215 which is
connected with the housing. One end portion of the bellows member
214 is urged by a spring 219. An opposing seal surface 212A of the
stationary seal ring 212 which is thus urged by the spring 219 via
the one end portion of the bellows member 214 is brought into
seal-tight contact with the seal surface 102A of the rotary seal
ring 102 shown in FIG. 6.
[0010] The way the device in FIG. 4 and FIG. 6 operates is
hereafter similar to one another. Therefore problems encountered in
FIG. 6 will be dealt with by referring to FIG. 4. It is noted that
parenthesized numerals correspond to those of FIG. 6. The
mechanical seal device 211(111) effects a seal against a sealed
fluid within the apparatus by bringing the opposing seal surface
212A of the stationary seal ring 212 into seal-tight contact with
the seal surface 202A of the rotary seal ring 202(102) as the
result of the stationary seal ring 212 being urged by the spring
219 via the bellows member 214. The sleeve member 203 is fittingly
fixed with the rotary shaft in order to rotate together. Then the
rotary seal ring 202(102) which is mounted to the mount portion
203D(103D) via the cup gasket 214(104) is forced to rotate together
with the rotary shaft after the engagement flat surface (102B)
engages the holding plate (103A). However, bringing the engagement
flat surface (102B) into seal-tight contact with the holding plate
(103A) is very difficult to achieve from the machining point of
view, because it requires that the cup gasket 214(104) be fitted
not only with the mount portion 203D(103D) but also with the rotary
seal ring 202(102). Also the holding plate (103A) needs to be
directly worked to obtain the annular mount portion 203D(103D) by a
press forming method, which will inevitably restrict machining
accuracy. In addition, pressing the holding plate (103A) too much
against the engagement flat surface (102B) causes unwanted strains
to the seal surface 202A.
[0011] As shown in FIG. 6, pressing a pair of the symmetrically
arranged engagement flat surfaces (102B) of the rotary seal ring
(102) causes deformation of the seal surface 202A. Therefore a
certain clearance is disposed between the engagement flat surface
(102B) and the holding plate (103A). The seal surface 202A and the
opposing seal surface 212A repeat a sticking and a relative sliding
motion one after the other because of elastic torsional deformation
of the cup gasket 204(104) in the circumferential direction and the
clearance gap existing between the width dimension B of the
engagement flat surface 102B and the width dimension A of the
holding plate 103A. The repeated sticking and relative sliding
motion causes a squealing noise. The sticking further accelerates
wear in the seal surface 202A. As the result, the seal ability of
the mechanical seal device 211(111) will decrease.
[0012] The present invention is introduced to resolve the above
mentioned problems. A primary technical goal which this invention
tries to achieve is to make part machining and assembly of a
mechanical seal device straightforward and to improve durability of
a gasket supporting a seal ring by protecting the gasket from
torsional fatigue. Another goal is to prevent squealing noises of a
seal surface during sliding movement thereof and to reduce wear of
the seal surface.
BRIEF SUMMARY OF THE INVENTION
[0013] A primary object of the present invention is to resolve the
above mentioned technical problems, and a solution to such problems
is embodied as follows.
[0014] A mechanical seal device related to the present invention is
a mechanical seal device providing a seal between a bore disposed
in a seal housing and a shaft extending through the bore by means
of a pair of seal rings. The mechanical seal device comprises a
first seal ring, a retainer ring and a gasket wherein the first
seal ring is one of a pair of the seal rings and disposes an
engagement portion at the outer circumferential surface, wherein
the retainer ring has a first support portion and a second support
portion and is fixed with either the seal housing or the shaft,
wherein the first support portion supports the first seal ring,
wherein the second support portion engages the engagement portion
to be locked in with each other in a rotational direction, wherein
the gasket is made of a rubber-like elastic material and is
disposed between the first support portion of the retainer ring and
the first seal ring and joins the first support portion and the
first seal ring, wherein the gasket is in a fixed contact relation
with the first support portion and the first seal ring, wherein an
engagement clearance formed in a rotational direction between an
engagement end portion of the second support portion and an
engagement wall of the engagement portion is within 0.5 mm.
[0015] In the mechanical seal device related to the present
invention, the second support portion engages the engagement
portion of the first seal ring to be locked in with each other in a
rotational direction in which the first seal ring is fittingly
fixed with the gasket, and the engagement clearance C between the
two components is arranged to be within 0.5 mm. This enables the
second support portion to constantly engage the engagement wall of
the engagement slot of the seal ring during rotation. This
engagement at the engagement wall allows the gasket to prevent wear
of the seal surfaces due to torsional torques induced by relative
sliding movement of the seal ring during the rotation. As a result,
the gasket is able to improve durability thereof. This also implies
that even if the seal ring is retained by a rubber-like elastic
gasket, the seal surfaces remain free of stick-and-slip motion
owing to the secure engagement between the engagement portion and
the second support portion, thus preventing squealing noises of the
seal surfaces under the sliding movement. Prevention of unwanted
squealing noises will be resulted in a prevention of wear of the
seal surfaces. This also will be able to avoid fatigue or damage of
the second support portion and associated contact portion thereof
due to collision contact therebetween.
BRIEF DESCRIPTION OF THE DRAWINGS
[0016] FIG. 1 is a cross sectional view of a mechanical seal device
as a first embodiment related to the present invention.
[0017] FIG. 2 is a front view of a portion of a retainer ring of a
first seal section in FIG. 1.
[0018] FIG. 3 is a plan view of FIG. 2.
[0019] FIG. 4 is a half cut-away sectional view of a mechanical
seal device as a relative art of the present invention.
[0020] FIG. 5 is a front view of a portion of the mechanical seal
device in FIG. 4.
[0021] FIG. 6 is a cross sectional view of a mechanical seal device
viewed from a seal surface as another relative art of the present
invention.
DETAILED DESCRIPTION OF THE INVENTION
[0022] Described below is the details of the figures of a preferred
embodiment of a mechanical seal device constructed in accordance
with the principles of the present invention. All the figures
explained below are constructed according to actual design drawings
with accurate dimensional relations. FIG. 1 depicts a cross
sectional view of a mechanical seal device M representing a first
embodiment relative to the present invention. FIG. 2 shows a front
view of a portion of a first seal section 1 in FIG. 1. FIG. 3 then
shows a plan view of the vicinity of a second support portion in
FIG. 2.
[0023] FIG. 1, FIG. 2 and FIG. 3 will be referred to in
descriptions below. The mechanical seal device M includes a pair of
seal sections; a first seal section 1 (at one side) and a second
seal section 11. (at the other side) which oppose against one the
other. A seal surface 2A of a first seal ring (one seal ring) 2
disposed in the first seal section 1 and an opposing seal surface
12A of a second seal ring (the other seal ring) 12 in the second
seal section 11 are brought into seal-tight contact with each other
in order to effect a seal against a sealed fluid. An inner
circumferential surface 2C and an end surface 2D of the first seal
ring 2 are adhered to a gasket 4 which is made of an elastic resin
material. The gasket 4 then is sealingly fitted with a retainer
ring 3 in order to join the first seal ring 2 and the retainer ring
3 together. The second seal ring 12, on the other hand, is
supported by a cartridge member 15 via a bellows member 14 and a
spring 19.
[0024] In FIG. 1, FIG. 2 and FIG. 3, a first seal ring 2 which
corresponds to the rotary seal ring has an annular form with a
rectangular cross section. Front end surface of the first seal ring
2 defines a first seal surface 2A which is mirror-finished. Then
the opposite side to the first seal surface 2A in the first seal
ring 2 defines an end surface 2D. Also the inner perimeter of the
first seal ring 2 forms an inner circumferential surface 2C.
Further, as illustrated in FIG. 2 and FIG. 3, an outer
circumferential surface 2E of the first seal ring 2 disposes three
engagement portions 2B there at which have a slot form and are
equally spaced apart along the outer perimeter. Slot width L of the
engagement portion 2B is arranged larger than the plate width W of
the second support portion 3A. One of the side walls of the slot in
the engagement portion (also called as engagement slot) 2B which is
located in the forward direction of rotation is defined as an
engagement wall 2B2. In general, there are a plurality of
engagement portions 2B which are equally spaced apart along the
circumference. In case that the engagement portion 2B pressed hard
by the second support portion 3A may cause strains to the seal
surface 2A, the engagement portions 2B are better arranged along
the circumference in an anti-symmetrical manner. Bottom surface 2B1
can be arranged so as to form a circular arc, or a portion of the
outer circumferential surface can be made to have a flat surface.
It is noted that the first seal ring 2 is made of a low-friction
hard material. Such low-friction hard materials include silicon
carbide, ceramics, super hard alloy, carbon and so on.
[0025] Retainer ring 3 is a sleeve member being made from a
stainless steel sheet, which has a cylindrical form as a whole. On
end portion of the cylindrical form defines a fixing portion 3C
which is fitted over the shaft 30. The other end portion relative
to the fixing portion 3C defines a first support portion 3D. The
first support portion 3D consists of a mount cylindrical portion
and a flange portion which extends from the end portion of the
mount cylindrical portion in a radial direction. And the outer
circumferential edge of the flange portion continues to form a
short outer ring 3B therefrom whose shape is either a circular arc
or a cylinder. The outer ring 3B disposes three sets of second
support portions 3A which are equally spaced apart along the
circumferential surface. This second support portion 3A (also
called cantilever beam), as shown in FIG. 2 and FIG. 3, is arranged
to have a form of a rectangular cantilever beam which extends from
the outer ring 3B in an axial direction. Longitudinal length of the
second support portion 3A should preferably be more or less the
same as that of the seal surface 2A of the first seal ring 2.
[0026] Also the beam width W of the cantilever beam 3A should be
smaller than the slot width L of the engagement portion 2B. This is
because a plurality of engagement portions 2B as well as a
plurality of second support portions 3A (for example, 3, 4 or 5
sets) are disposed along the circumference and it becomes extremely
difficult to align all the second support portions 3A with the
mating engagement portions 2B if the beam width W of the second
support portion 3 were the same as the slot width L of the
engagement portion 2B. In general, the more slots and beams along
the circumference, the more difficulties in fitting the two mating
components with each other. In practice, if the slot width L and
the beam width W are arranged to have an identical dimension and
are subjected to a highly precise fit, the individual contact
surfaces of both members need to be finished by lapping or the
like. Therefore completing even one pair takes a lot of time and
this will lead to a substantial increase in manufacture cost and
assembly cost, which will eventually push it out of reach from the
standpoint of industrial interests. The second support portion 3A
has an engagement end portion 3A1 at side wall thereof in the
direction of rotation which engages an engagement wall 2B2 of the
engagement portion 2B. Furthermore, the second support portion 3A
should preferably be reinforced by forming a rugged or wavy profile
on the surface and also dispose an engagement end portion 3A1 which
comes into contact with the engagement wall 2B2 of the engagement
portion 2B.
[0027] The engagement portion 2B of the first seal ring 2 and the
second support portion 3A are assembled as shown in FIG. 2 and FIG.
3. Direction of rotation of the first seal portion 1 in FIG. 2 and
FIG. 3 is represented by N. Assembly of the engagement portion 2B
and the second support portion 3A is arranged such that the
engagement wall 2B2 of the engagement portion 2B and the engagement
end portion 3A1 of the second support portion 3A form an engagement
clearance therebetween to the direction of rotation N which is less
than 0.5 mm. The engagement clearance C should preferably be less
than 0.1 mm. Assembly of the respective second support portions 3A
and engagement portions 2B under an engagement clearance C of less
than 0.1 mm is feasible from the manufacture standpoint because the
engagement clearance C is disposed at only one side of the two side
walls of the second support portions 3A. This way of assembling the
engagement wall 2B2 of the engagement portion 2B makes it
straightforward to keep the engagement clearance C within 0.5 mm
even under the presence of spring-back of the gasket 4. Also a
dimensional relationship between the slot width L and the beam
width W should be determined by considering the strength of the
beam width W due to a rotational torque of the first seal ring 2.
Then the slot width L should be chosen such that the second support
portion 3A can easily be mated with the engagement portion 2B in
the assembly process of the first seal ring 2 and the retainer ring
3. This will substantially decrease a manufacture cost of the
engagement portion 2B and the second support portion 3A.
[0028] The second support portion 3A should be set in a non-contact
state relative to the bottom surface 2B1 of the engagement portion
2B for the ease of assembly. In case that there is a need to bring
the second support portion 3A into a contact state with the bottom
surface 2B1 of the engagement portion 2B, a dimensional
interference should be in a range of from 0 to 0.30 mm. More
preferably, the interference should be in a range of from 0.01 mm
to 0.25 mm. That is, the interference of the second support portion
3A is formed radially inward relative to the radius of the
engagement portion 2B. This level of interference of the second
support portion 3A does not cause serious strains to the seal
surface. The free end portion of the second support portion 3A may
be bent radially outward so that the first seal ring 2 can easily
be inserted to the second support portion 3A. Material for the
retainer ring 3 should be determined according to the
characteristics of the sealed fluid, e.g., stainless steel,
aluminum, copper, steel plate or the like.
[0029] The cup gasket 4 comes into sealing contact with a
cylindrical mount portion as well as with a flange portion of the
first support portion 3D in the retainer ring 3. The cup gasket 4
fixedly joins the first seal ring 2 with the first support portion
3D of the retainer ring 3 by forming sealing contact with the inner
diameter surface 2C as well as the end surface 2D of the first seal
ring 2. The gasket 4 consists of a flange support portion 4A and a
fit portion 4B the latter of which has a cylinder form axially
extending from the inner diameter portion of the support portion 4.
The inner diameter surface of the fit portion 4B in the gasket 4
comes in fitting contact with the first support portion 3D while
the outer diameter surface of the fit portion 4B is brought into
sealing contact with the inner diameter surface 2C of the first
seal ring 2. The fit portion 4B and the first seal ring 2 are
fittingly connected with each other so that they rotate together in
an integral manner. Also the support portion 4A provides the first
seal ring 2 with a resilient support in the axial direction.
Therefore, the gasket 4 not only is able to effect a seal against a
sealed fluid in order to prevent the fluid from leaking from
between the retainer ring 3 and the first seal ring 2, but also
resiliently urges the first seal ring 2 against the retainer ring
3. This gasket 4 is made of a rubber material, preferably FKM, NBR,
IIR, U, Q, CR or the like.
[0030] A second seal ring 12 which opposes to the first seal ring 2
is supported by a cartridge member 15 in a freely slidable manner
which is made of stainless steel plate. A rubber made bellows
member 16 is disposed between the second seal ring 12 and the
cartridge member 15. A first mount ring 13 is fitted with the one
end portion of the bellows member 16 such that a spring 19 can
exert an urging force thereto. Thus the bellows member 16 and the
spring 19 resiliently urge the second seal ring 12 against the
first seal ring 2. The first mount ring 13 securelly holding the
outer circumference surface of the bellows member 16 causes the
inner diameter surface to be fixed to the outer diameter surface of
the second seal ring 12. Also the other end of the bellows member
16 is securely fixed to the cartridge member 15 by means of a
second mount ring 14. The cartridge member 15 comes into fit
contact at a fixing portion 15A with a bore section of a seal
housing member 60 and is fixedly settled by bringing a flange
portion 15B into contact with the end surface of the seal housing
member 60. The second seal ring 12 is also made of one of
low-friction hard materials which are in general preferably used.
Such hard materials include silicon carbide, carbon, super hard
alloy and so on.
[0031] A mechanical seal device of a second embodiment related to
the present invention is not shown here. What makes the current
mechanical seal device different from the mechanical seal device 1
of FIG. 1 is in a second support portion 3A of a retainer ring 3
which is disposed in a first seal portion 1. The second support
portion 3A which is represented by the same reference numeral as
that in FIG. 1 forms an outer ring 3B which cylindrically extends
from the outer circumferential end of the first support portion 3D.
A plurality of second support portions 3A are formed by slitting at
the outer ring 3B in a equally spaced manner such that the width W
of the beam becomes smaller than the slot width L of the engagement
portion 2B. Then the second support portion 3A which has a form of
cantilever beam can be slightly bent radially inward such that an
interference between the bottom surface 2B1 of the engagement
portion 2B and the mating contact surface of the second support
portion 3A becomes about 0.15 mm. This interference should be in a
range of from 0 to 0.30 mm. More preferably, the interference H of
the second support portion 3A relative to the engagement portion 2B
should be in a range of from 0.01 mm to 0.25 mm. Manufacturing the
second support portion 3A from the outer ring 3 in this manner
allows a fine adjustment of the length of the second support
portion 3A by means of controlling the slitting depth in the axial
direction. Therefore, spring-back of the second support portion 3A
urging the engagement portion 2B can be held small, thus improving
strength of the second support portion 3A.
[0032] Testing results of a mechanical seal device M of the present
invention shown in FIG. 1 and a mechanical seal device 211 as a
comparison example shown in FIG. 4 and FIG. 5 are given below
wherein squealing noises during relative sliding motion of the seal
surfaces are evaluated.
[0033] A. Testing machine
[0034] 1) Drilling machine type mechanical seal unit testing
machine (commercially available testing apparatus in which a
mechanical seal device is installed in a liquid tank and a fluid
leaking from the seal surfaces is subject to measurement after the
fluid is sunk to the bottom.)
[0035] B. Test conditions
[0036] 1) Rotational speed of the seal rings is 0 to 2000 rpm,
being varied therebetween.
[0037] 2) Liquid temperatures of the sealed fluid adopted are 40,
60, 80 and 100 degrees in Celsius.
[0038] 3) Sealed fluid pressure used is an atmospheric
pressure.
[0039] 4) Type of sealed fluid used is 50% water solution of LLC
(Long Life Coolant).
[0040] 5) Slot width L of an engagement portion 2B is 5.5 mm.
[0041] 6) Beam width W of a second support portion 3A is 4 mm.
[0042] 7) Engagement clearance C is 0.5 mm.
[0043] C. Testing results
[0044] 1) Mechanical seal device M of the present invention
Occurrence of squealing noise with the present invention is 3% to
10% (note: noise was observed in the vicinity of 60 degree in
Celsius and less than 500 rpm).
[0045] 2) Mechanical seal device 211 of the comparison example
Occurrence of squealing noise with the comparison example is 25% to
35%.
[0046] 3) The above results clearly indicate that the mechanical
seal device of the present invention gives much less chance of
squealing noise than the comparison example.
[0047] Next, how to assemble the first seal portion 1 in FIG. 1
will be explained below. First, the engagement portion 2B and
second support portion 3A of the first seal portion 1 are assembled
as shown in FIG. 2 and FIG. 3. A rubber made cup gasket 4 is
inserted to the first support portion 3D of the retainer ring 3
from the distal end portion 3C in an expanded form in order to
bring the gasket 4 into fitting contact with the first support
portion 3D. Press fitting forces a fit surface 4B1 of a fitting
portion 4B of the gasket 4 to fit with the inner diameter surface
2C of the first seal ring 2. Alternatively the gasket 4 can engage
the inner diameter surface 2C of the first seal ring 2 whose
surface has a rugged or wavy profile. Engagement clearance C formed
between the engagement end portion 3A1 of the second support
portion 3A and the engagement wall 2B2 of the engagement portion 2B
should be less than 0.5 mm after pres fitting of the fit surface
4B1 of a fitting portion 4B of the gasket 4 to the inner diameter
surface 2C of the first seal ring 2. The radially inner surface of
the second support portion 3A1 is kept in a non-contact state
relative to the bottom surface 2B1 of the engagement portion 2B. If
a contact engagement of the second support portion 3A1 against the
bottom surface 2B1 of the engagement portion 2B is preferred, then
the interference of the second support portion 3A1 should be chosen
in a range of from 0 mm to 0.30 mm. It is also confirmed that a
squealing noise is hardly observed during relative sliding movement
of the seal surfaces if the engagement clearance C between the
engagement end portion 3A1 of the second support portion 3A and the
engagement wall 2B2 of the engagement portion 2B in the first seal
ring 2 is kept in less than 0.5 mm after the completion of
assembly.
[0048] Next, preferred exemplary embodiments of the other
inventions related to the present invention are described
below.
[0049] In a mechanical seal device M as a second exemplary
embodiment related to the present invention, an engagement portion
2B is defined by an engagement slot which extends in an axial
direction and a second support portion 3A is defined by a
cantilever beam which is inserted into the engagement slot.
[0050] According to the mechanical seal device M of the second
exemplary embodiment, since the second support portion 3A axially
extends from a first support portion 3D so as to form a cantilever
beam and the cantilever beam is inserted into the engagement slot
(engagement portion 2B), it becomes straightforward to deploy an
engagement if an engagement clearance C between an engagement end
portion 3A1 of the cantilever beam and an engagement wall 2B2 of
the engagement portion 2B is arranged to be within 0.5 mm. In
particular a straightforward insertion of the cantilever beam into
the engagement slot implies am easy machining of the cantilever
beam and engagement slot, thus resulting in a decrease in the
machining cost. This also contributes to not only prevention
against squealing noises of the respective seal surfaces 2A, 12A
but also prevention against wear associated with the squealing
noises. This ensures a prolonged seal ability of the mechanical
seal device M.
[0051] In a mechanical seal device M as a third exemplary
embodiment related to the present invention, a dimensional
interference chosen for the inner circumferential surface of a
second support portion 3A against the bottom surface 2B1 of an
engagement portion (engagement slot) 2B is in a range of from 0 to
0.25 mm.
[0052] According to the mechanical seal device M of the third
exemplary embodiment, the bottom surface 2B1 of the engagement
portion 2B and the opposing mating surface of the second support
portion 3A are subjected to an interference fit with an
interference of 0 to 0.25 mm. When the dimensional interference
which determines the contact pressure between the second support
portion 3A and the engagement portion 2B is arranged in a range of
from 0.01 mm to 0.25 mm, undesirable surface strains which
deteriorate seal ability are hardly observed at the seal surface 2A
of the first seal ring 2. Therefore, a certain dimensional error
can be tolerated for the interference C which is formed between a
plurality of engagement portions 2B and a plurality of second
support portions 3A on the circumferential surface of the first
seal ring 2 while a secure engagement between the first seal ring 2
and the second support portion 3A is being maintained. Further, the
second support portion 3A is kept in contact with the engagement
portion 2B even when the mechanical seal device M is subjected to
external vibratory forces, and a defective engagement of the second
support portion 3A against the engagement portion 2B caused by
oscillation of the second support portion 3A during rotation can
also be prevented. Such a secure engagement between the second
support portion 3A and the engagement portion 2B will effectively
prevent occurrence of squealing noises as well.
[0053] In a mechanical seal device M as a fourth exemplary
embodiment related to the present invention, a plurality of pairs
consisting of engagement portions (engagement slots) 2B of a first
seal ring 2 and second support portions 3A of a retainer ring 3 are
arranged on the circumferential surface under an engagement
relation with one the other, and the respective second support
portions 3A are arranged in a non-contact state against
corresponding bottom surfaces 2B1 of the engagement portions
2B.
[0054] According to the mechanical seal device M of the fourth
exemplary embodiment, a plurality of the engagement portions 2B of
the first seal ring 2 and a plurality of the second support
portions 3A of the retainer ring 3 are arranged in pairs along the
circumferential surface and the respective bottom surfaces 2B1 of
the engagement portions 2B remain in a non-contact state against
the second support portions 3A. This makes assembly of the second
support portions 3A and engagement portions 2B straightforward and
several second support portions 3A (four to six units) can be
engaged with several engagement portions 2B (also four to six
units) of the first seal ring 2. And durability of the seal device
will improve in accordance with the increased strength provided by
the secure engagement between the second support portions 3A and
the first seal ring 2. Such a strong engagement of the second
support portions 3A with the first seal ring 2 will lead not only
to an outstanding seal ability of the respective seal surfaces 2A,
12A but also to prevention against squealing noises during relative
sliding movement. This also will prevent wear of the respective
seal surfaces 2A, 12A accordingly.
[0055] In a mechanical seal device M as a fifth exemplary
embodiment related to the present invention, second support
portions 3A are formed in an outer ring 3 which fits a first seal
ring 2, and the cantilever beams which are machined by slitting the
outer ring3 in the axial direction are bent toward a radially
inward direction of engagement portions 2B.
[0056] According to the mechanical seal device M of the fifth
exemplary embodiment, the second support portions 3A are defined as
cantilever beams wherein the cantilever beams are formed by
slitting the cylindrical outer ring 3 in the axial direction
surrounding the first seal ring 2 and are bent toward a radially
inward direction of engagement portions 2B. This arrangement
enables the cantilever beams not only to increase strength thereof
along the rotational direction owing to retaining by the outer ring
3 but also to engage the engagement portions 2B in a more secure
manner. Also the integral construction of the cantilever beams and
the outer ring 3 prevents a spring-back of the beams and allows a
specified interference to exhibit a necessary retaining force
against the engagement portions 2B. This in turn not only prevents
occurrence of squealing noises at respective seal surfaces 2A, 12A
during relative sliding movement but also decreases wear of the
seal surfaces 2A, 12A.
[0057] Mechanical seal device of the present invention is effective
for sealing against a sealed fluid in pumps of radiator, cooler,
compressor or the like which are typically used in automobiles or
construction machinery. In particular, the seal device enjoys a
high seal ability, almost no squealing noise admitted during the
rotation, and a high protection against wear of the seal
surfaces.
[0058] Having described specific embodiments of the invention,
however, the descriptions of these embodiments do not cover the
whole scope of the present invention nor do they limit the
invention to the aspects disclosed herein, and therefore it is
apparent that various changes or modifications may be made from
these embodiments. The technical scope of the invention is
specified by the claims.
* * * * *