U.S. patent number RE33,715 [Application Number 07/098,041] was granted by the patent office on 1991-10-15 for shock absorber.
This patent grant is currently assigned to NOK Corporation. Invention is credited to Takeshi Miura.
United States Patent |
RE33,715 |
Miura |
October 15, 1991 |
Shock absorber
Abstract
A shock absorber capable of effectively preventing a gas from
leaking from a gas chamber, maintaining an oil seal in a
firmly-held state, and preventing the reciprocating movements of a
rod from adversely affecting the function of the oil seal,
comprising an oil cylinder and a gas tube, which are joined
together in a concentrically-arranged state to form a gas chamber
therebetween; a rod, which is moved reciprocatingly in the oil
cylinder; a bearing having an axially extending cylindrical support
portion and fixed to an end portion of the oil cylinder to form an
oil chamber in cooperation with the oil cylinder and rod support in
such a manner that the rod can be slidingly moved; and an oil seal,
which has a main lip sealingly slidable with respect to a
circumferential surface of the rod, and a frustoconical check valve
lip resiliently contacting an outer surface of the cylindrical
support portion and adapted to allow an oil to flow from the oil
chamber to the gas chamber and prevent the oil from flowing in the
opposite direction, and the seal is held on the cylindrical support
portion as a radially-extending portion, with which the main lip
and check valve lip are connected integrally with each other.
Inventors: |
Miura; Takeshi (Fukushima,
JP) |
Assignee: |
NOK Corporation
(JP)
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Family
ID: |
26474773 |
Appl.
No.: |
07/098,041 |
Filed: |
September 17, 1987 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
Issue Date |
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Reissue of: |
436711 |
Oct 26, 1982 |
04542811 |
Sep 24, 1985 |
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Foreign Application Priority Data
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Sep 21, 1982 [JP] |
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57-142915 |
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Current U.S.
Class: |
188/322.17;
188/315; 277/574 |
Current CPC
Class: |
F16F
9/364 (20130101) |
Current International
Class: |
F16F
9/36 (20060101); F16F 009/36 () |
Field of
Search: |
;188/322.17,322.21,315
;267/64.28 ;277/27,152,153,181,182,183 ;92/168R |
References Cited
[Referenced By]
U.S. Patent Documents
Foreign Patent Documents
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32988 |
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Aug 1981 |
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EP |
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78834 |
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Jun 1980 |
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JP |
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103130 |
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Aug 1980 |
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JP |
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2045892 |
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Nov 1980 |
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GB |
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Primary Examiner: Halvosa; George E. A.
Attorney, Agent or Firm: Perry; Owen E. White; Charles
R.
Claims
What is claimed is:
1. A shock absorber comprising an oil cylinder 1 and a gas tube 2,
which are jointed together in a concentrically-arranged state to
form a gas chamber 3 therebetween; a rod 4 moved reciprocatingly in
said oil cylinder 1; and a bearing 5 having an axially extending
cylindrical support portion 21, fixed to an end portion of said oil
cylinder 1, forming an oil chamber 6 in cooperation with said oil
cylinder 2 and said rod 4, said axially extending cylindrical
support portion 21 having a communication groove 31 and
.Iadd.having cylindrical surface means .Iaddend.supporting said rod
4 in such a manner that said rod 4 can be slidingly moved; and
.[.an.]. .Iadd.a unitized .Iaddend.oil seal 10 .Iadd.having a
portion .Iaddend.reinforced by an annular reinforcing member 33,
which has a main lip 25 sealingly slidable with respect to a
circumferential surface of said rod 4, and a check valve lip 12
.Iadd.disposed radially outward of said main lip 25 .Iaddend.having
substantially frusto-concial shape, resiliently .[.contracting.].
contacting an outer circumferential surface of said cylindrical
support portion 21, and adapted to allow an oil to flow from said
oil chamber 6 to said gas chamber 3, and prevent a gas from flowing
in the opposite direction, and whose reinforced portion is firmly
held between said bearing 5 and inwardly-extending flange portion
28 provided at the end portion of said gas tube 2 as a
radially-extending portion 24, with which said main lip 25 and said
check valve lip 12 are connected integrally with each other
.[.is.]. .Iadd.and said reinforced portion being .Iaddend.supported
on said cylindrical support portion 21.
2. A shock absorber according to claim 1, wherein said oil seal 10
is fitted in an oil seal cover 9 having a cylindrical portion 27
and said inwardly extending flange portion 28 and joined at said
cylindrical portion 27 to said gas tube 2 so as to firmly hold said
oil seal 10 between said inwardly-extending flange portion 28 and
said cylindrical support portion 21.
3. A shock absorber according to claim 1, wherein said oil seal 10
has a .[.fixing.]. .Iadd.sealing .Iaddend.portion 34 at an outer
circumferential end thereof, which fixing portion 34 is firmly
sandwiched between said inwardly-extending flange portion 28 of
said gas tube 2 and said bearing 5. .Iadd.
4. In a shock absorber of the type having an oil cylinder 1 and a
gas tube 2 concentrically arranged to form a gas chamber 3
therebetween; a reciprocable rod 4 having a cylindrical
circumferential surface disposed in said oil cylinder 1; a bearing
5 having seating means 21a thereon and being fixed to an end
portion of said oil cylinder 1 and forming an oil chamber 6 in
cooperation with said oil cylinder 1 and said rod 4, and slidingly
supporting said rod 4, the improvement comprising a unitized seal
assembly 10 for said shock absorber having body means 10a
cooperating with the bearing 5 for forming an inner chamber 16
above and in communication with the oil chamber 6, said seal
assembly 10 further including an annular reinforcing member 33 for
reinforcing said body means 10a, an annular oil sealing lip 25
integral with said body means 10a sealingly and slidable with
respect to a circumferential surface of said rod 4, an annular dust
sealing lip axially spaced from said oil sealing lip integral with
said body means sealingly and slidably contacting the
circumferential surface of said rod, an annular check valve lip 12
integral with said body means and disposed radially outward of said
oil sealing lip for sealingly contacting said seating means 21a on
said bearing 5 to form a one-way valve to block the flow of gas
from said gas chamber to said inner chamber 16 and deflectable from
said seating means when said rod strokes outwardly with respect to
said oil chamber 6 and to thereby allow oil to flow from said oil
chamber 6 to said gas chamber 3, said reinforcing member 33
extending outwardly from said body means to an outer periphery to
support said oil and dust sealing lips with respect to said check
valve lip 12 for maintaining a preset dimensional relationship
therebetween, and sealing means associated with the outer periphery
of said reinforcing member and disposed radially outward of said
annular check valve lip for sealing said gas chamber. .Iaddend.
.Iadd.
5. A shock absorber according to claim 4 wherein said bearing 5 has
an axially extending cylindrical support portion 21, said check
valve lip 12 is biased against said bearing 5 at said axially
extending cylindrical support portion 21, and wherein said seating
means 21a on said bearing 5 is an outer circumferential surface on
said cylindrical support portion 21. .Iaddend. .Iadd.6. A shock
absorber according to claim 5 wherein said cylindrical support
portion 21 includes a communication groove 32 for providing fluid
communication between said oil chamber 6 and said gas chamber 3.
.Iaddend. .Iadd.7. A unitized seal for a shock absorber of the type
having an oil cylinder 1 and a gas tube 2 concentrically arranged
to form a gas chamber 3 therebetween; a cylindrical rod 4 disposed
for linear reciprocating motion in said oil cylinder 1; a bearing 5
having seating means thereon and being fixed to an end portion of
said oil cylinder 1 and forming an oil chamber 6 in cooperation
with said oil cylinder 1 and slidingly supporting said rod 4, and a
seal cover affixed to the gas tube and having a central opening
through which said rod extends, said unitized seal comprising:
generally cylindrical seal body means 10a and an annular sealing
flange portion 24 extending from said body means and cooperating
with the bearing 5 for forming an inner chamber 16 above and in
hydraulic communication with the oil chamber 6, said flange portion
of said unitized seal 10 being reinforced by an annular reinforcing
member 33 extending from said seal body means, a radial inner oil
seal lip 25 on said seal body means sealingly slidable with respect
to a circumferential surface of the rod 4, a radial inner dust seal
lip on said seal body means separate from said oil seal lip for
sealing engagement with said rod, a check valve lip 12 integral
with said sealing flange portion and disposed radially outward of
said oil seal lip for resiliently contacting said seating means on
the bearing 5 for deflection outwardly from said seating means to
allow oil to flow from the oil chamber 6 to the gas chamber 3 when
said rod moves in an outward direction with respect to said
cylinder and to subsequently recover into sealing engagement with
said seating means when said rod moves in an inward direction with
respect to said cylinder to prevent gas from flowing in the
opposite direction from said gas chamber to said inner chamber 16,
said flange portion being firmly held between the bearing 5 and the
seal cover and wherein said flange portion as reinforced by said
reinforcing member integrally joins said seal body
means 10a to said check valve lip 12. .Iaddend. .Iadd.8. The
unitized seal according to claim 7 wherein said bearing 5 has an
axially extending cylindrical support portion 21, said check valve
lip 12 resiliently engages said bearing 5 at said axially extending
cylindrical support portion 21, and wherein the seating means 21a
on the bearing 5 is an outer circumferential surface on said
cylindrical support portion 21. .Iaddend. .Iadd.9. A seal according
to claim 7 wherein the cylindrical support portion 21 includes a
communication groove 31 for providing fluid communication between
the oil chamber 6 and the gas chamber 3. .Iaddend. .Iadd.10. A seal
according to claim 7 wherein said check valve lip 12 has a
substantially frusto-conical shape and includes at least one
annular surface 12a adapted to define, in cooperation with said
seating means 21a a generally circular, radially inward acting
excluder seal band. .Iaddend. .Iadd.11. A unitized seal for a
damper device having a first part and a second part concentrically
arranged to form a gas chamber 3 therebetween; a cylindrical rod
member mounted for reciprocating movement in said first part; a
bearing 5 having seating means thereon and being fixed to an end
portion of said first part and forming an oil chamber 6 in
cooperation with said first part and said reciprocating rod member,
said bearing having a control opening slidingly supporting said
reciprocating member, said damper device further having a cap
member, said seal comprising: body means 10a of a rubber like
material cooperating with the bearing 5 for forming an inner hollow
chamber 16 in hydraulic communication with the oil chamber 6, an
annular main oil sealing lip 25 radially inward from said body
means 10a sealingly slidable with respect to a circumferential
surface of the reciprocating member, an annular resilient check
valve lip 12 integral with said body means 10a and disposed
radially outward of said oil sealing lip and sealingly contacting
the seating means 21a on the bearing 5 and deflectable away from
sealing contact with said seating means to provide an opening to
allow oil to flow from the oil chamber 6 to the gas chamber 3 when
said reciprocable member strokes out of said oil chamber 6, and
recoverable into sealing contact with said seating means to prevent
a gas from flowing in the opposite direction when said reciprocable
member strokes in an inward direction with respect to said oil
chamber 6, said body means 10a having a reinforced portion
extending to a terminal edge to be firmly held between the bearing
5 and the cap member and wherein said reinforced portion integrally
joins said main lip 25 to said check valve lip 12 for maintaining a
preset dimensional relationship therebetween, and an outer annular
seal means associated with
said terminal edge for sealing said gas chamber. .Iaddend.
.Iadd.12. A singular unitized fluid seal unit for installation in a
piston-and-rod type hydraulic and gas-charged shock absorber
comprising a discrete generally cylindrical and centralized body
means of rubber-like material having a central piston rod opening
therethrough about a longitudinal axis, said body means having
first and second annular lip seal means integral with said body
means and extending radially into said piston rod opening and
defining an inner diameter of said unit, said body means having an
annular thin wall flange extending radially outward from integral
connection with said body means and a generally cylindrical seal
portion depending along a line of revolution substantially parallel
to said axis from integral connection with said thin wall flange,
said depending cylindrical seal portion being radially spaced from
and encompassing said cylindrical body means, third annular lip
seal means on an end of said depending cylindrical seal portion,
said third annular lip seal means being resiliently deflectable
radially away from said axis from its unstressed position to define
a check valve seal, and a reinforcing casing associated with said
thin wall flange and extending from connection with said
cylindrical body and extending generally radially outward therefrom
to provide a securement to facilitate operative installation of
said fluid seal unit into a shock absorber. .Iaddend. .Iadd.13.
Improvement for a shock absorber having an oil cylinder
concentrically received in an outer tube with a gas chamber defined
therebetween and affixed to a piston rod bearing means operatively
mounted to adjacent ends of said oil cylinder and said outer tube,
said improvement comprising a single unitized fluid seal unit for
installation in the shock absorber having a generally cylindrical
and centralized body means of rubber-like material of a
predetermined height with discrete upper and lower ends and having
a central piston rod opening therethrough about a longitudinal
axis, said body means having first and second annular lip seal
means integral with said body means and extending radially into
said piston rod opening and defining an inner diameter of said
unit, said body means having an annular thin wall flange extending
radially outward from integral connection with an annular area
between the ends of said body means to a terminal position, a
cylindrical seal portion depending along a line of revolution
substantially parallel to said axis from integral connection with
said thin wall flange, said depending cylindrical seal portion
being radially spaced from said cylindrical body means, third
annular lip seal means on the end of said depending cylindrical
seal portion, said third annular lip seal means being resiliently
deflectable outwardly from an initial position sealingly engaging
the bearing means to define a check valve seal, and a reinforcing
casing associated with said thin wall flange and extending from
direct connection with said cylindrical body to provide a
securement to facilitate operative installation of said fluid seal
unit into the shock absorber. .Iaddend.
Description
BACKGROUND OF THE INVENTION
This invention relates to a double cylinder type shock absorber
having an oil chamber and a gas chamber, and more particularly to a
shock absorber capable of effectively preventing a gas in a gas
chamber from leaking therefrom.
In a double cylinder type shock absorber using an oil and a gas and
consisting of a combination of a hydraulic means composed of a
piston and an oil cylinder and a gas tube provided concentrically
on the outer side of the hydraulic means to form a gas chamber
therebetween, it is necessary that a means for preventing the
leakage of a pressure gas in addition to a seal means for
preventing the leakage of a pressure oil be devised. FIG. 1 shows
an example of a double cylinder type shock absorber, which is
disclosed in Japanese Published Unexamined Utility Model
Application No. 1979-53193, and which is provided with seal means
of the above-mentioned kind for preventing the leakage of a
pressure oil and a pressure gas. This shock absorber has the
following constructional elements. Namely, it is provided with a
smaller-diameter oil cylinder 1 and a larger-diameter gas tube 2,
which are joined together in a concentrically arranged state to
form a gas chamber 3 therebetween; a piston (not shown) mounted
fixedly on an end portion of a rod 4 and disposed in the oil
cylinder 1 in such a manner that the piston can be moved in the
axial direction thereof; a bearing 5 adapted to guide the
reciprocating movements of the rod 4, fixed to an end portion of
the oil cylinder 1, and forming an oil chamber 6 in cooperation
with the oil cylinder 1 and rod 4; an oil seal cover 9 supported on
an end portion of the gas tube 2; an oil seal 10 consisting of a
rubber-like elastic material, disposed on the inner side of the oil
seal cover 9, and adapted to preventing an oil from leaking outside
and the external dust from entering an inner space on the side of
the bearing 5; a check valve 11 consisting of a rubber-like elastic
material, having a check valve lip 12 fixed to a washer 13, having
a substantially L-shaped cross-section, and disposed in a position
adjacent to the oil seal 10; a conical circumferential surface 15
formed on the portion of the bearing 5 which is on the side of the
oil seal with the check valve lip 12 resiliently contacting the
conical circumferential surface 15 to form an inner hollow chamber
16 on the side of the rod 4 and an outer hollow chamber 17 on the
side of the oil seal cover 9; a coiled spring 18 disposed in the
outer hollow chamber 17 and adapted to urge the check valve 11
toward the oil seal 10; and a communication bore 19 formed suitably
in the vicinity of the outer circumferential surface of the bearing
5 so as to communicate the outer hollow chamber 17 with the gas
chamber 3.
When the piston and rod 4 in the above shock absorber are moved
upward, the pressure in the oil chamber 6 increases, so that a part
of the oil flows into the inner hollow chamber 16 through a
clearance between the bearing 5 and rod 4. At this time, the oil
seal 10 prevents the oil from leaking outside. Consequently, the
check valve lip 12 is expanded, so that the oil flows into the
outer hollow chamber 17. The oil then flows through the
communication bore 19 into the gas chamber 3 to be mixed with the
oil existing in a lower portion thereof. When the piston and rod 4
are moved downward, the pressure in the oil chamber 6 decreases,
and the lip 12 of the check valve 11 is brought into press contact
with the conical circumferential surface of the bearing 5.
Accordingly, the pressure gas in the gas chamber 3 and outer hollow
chamber 17 is prevented from flowing into the inner hollow chamber
16.
In the above shock absorber, the oil seal 10 and check valve 11 are
supported on the coiled spring 18. Therefore, the actions of the
oil seal 10, which is drawn downward due to the friction between
the rod 4 and oil seal 10, especially, during a downward stroke of
the rod 4, having influence on the contacting condition of the
check valve lip 12 and the conical circumferential surface 15 of
the bearing 5. There is the possibility in such a shock absorber
that the pressure gas in the gas chamber 3 leaks into the inner
hollow chamber 16 and flows into the oil chamber 6 to be mixed with
the oil, or to leak outside through the sliding portions of the oil
seal 10 and rod 4.
SUMMARY OF THE INVENTION
An object of the present invention is to provide a shock absorber,
which is free from the drawbacks encountered in the above-described
prior art shock absorber, and which is provided with
stably-supported oil seal and check valve lip.
In order to achieve the above object, a shock absorber according to
the present invention is constructed as follows. A bearing, which
supports a reciprocatingly-movable rod, is provided at a radially
intermediate portion thereof with a cylindrical support portion
extending in the axial direction thereof, and a main lip, which is
adapted to sealingly slide on a circumferential surface of the rod
and prevent an oil from leaking outside and the external dust from
entering the interior of the shock absorber, and a check valve lip
resiliently contacting an outer circumferential surface of the
cylindrical support portion are fixed unitarily to a reinforcing
member of a metal sheet to form an oil seal, which is joined to a
gas tube as a radially extending portion thereof, which is formed
between the main lip and check valve lip, is supported at an inner
surface thereof on an end surface of the cylindrical support
portion. The oil seal and gas tube are joined together by fitting
the oil seal in an oil seal cover, which is formed independently
thereof so as to have a cylindrical portion and an
inwardly-extending flange portion, and which has a substantially
L-shaped longitudinal section, to support the radially-extending
portion of the oil seal, which is formed between the main lip and
check valve lip thereof, on the end surface of the cylindrical
support portion of the bearing, and join the cylindrical portion of
the oil seal cover to an end portion of the gas tube, or
sandwiching an outer circumferential end portion of the oil seal
between an outer end portion of the bearing and a bent end portion
of the gas tube. The cylindrical support portion extending from
bearing is provided in the end surface thereof with grooves for
communicating the inside and outside thereof with each other.
.Iadd.Another object of the present invention is to provide a new
and improved unitized seal for an oil and a gas charged shock
absorber having an annular lip deflectable outward from a central
axis to define a check valve seal. .Iaddend.
The above and other objects as well as advantageous features of the
invention will become apparent from the following description of
the preferred embodiments taken in conjunction with the
accompanying drawings.
BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1 is a sectional view of an example of a prior art shock
absorber;
FIG. 2 is a sectional view of an embodiment of the present
invention; and
FIG. 3 is a sectional view of another embodiment of the present
invention.
DESCRIPTION OF THE PREFERRED EMBODIMENTS
The embodiments of the shock absorber according to the present
invention will now be described with reference to the drawings. In
the embodiment shown in FIG. 2, a bearing 5, which is fitted to end
portions of an oil cylinder 1 and a gas tube 2 to form a gas
chamber 3 between the oil cylinder 1 and gas tube 2, and an oil
chamber 6 between the oil cylinder 1 and a rod 4, and which
supports the rod 4, is provided with a cylindrical support portion
21 on the opposite side of the oil chamber 6, which support portion
21 extends in the axial direction of the bearing 5. The oil seal
10.[.,.]. .Iadd.is a unitized or singular seal unit with a
generally cylindrical main body means 10a having a centralized
opening with a longitudinal axis through which rod 4 extends. As
shown, the oil seal is .Iaddend.reinforced by an annular
reinforcing member 33 of a substantially L-shaped longitudinally
section, has a substantially cylindrical .Iadd.seal and
.Iaddend.fixing portion 23 formed at a radially outer section
thereof.[.,.]. .Iadd.which extends along a line of revolution
substantially parallel to the axis of the axis of the rod opening
of the seal. The cylindrical portion 23 is integrally connected to
the main body 10a by .Iaddend.a bull's eye type radially-extending
.Iadd.flange .Iaddend.portion 24.[.,.]..Iadd.. The main body has
inwardly extending .Iaddend.a main .[.lip.]. .Iadd.oil and dust
seal lip means generally indicated at .Iaddend.25 sealing sliding
on a circumferential surface of the rod 4, and check valve lip 12
extending inward in the diagonal direction from a lower end of the
cylindrical .Iadd.seal and .Iaddend.fixing portion 23 and having a
substantially frusto-conical shape. The oil seal 10 is fitted in a
cylindrical portion 27 of an oil seal cover 9, which has the
cylindrical portion 27 and an inwardly extending flange portion 28,
and which is formed to have a substantially L-shaped longitudinal
section and joined to the end portion of the gas tube 2. The
radially-extending portion 24 reinforced by the annular reinforcing
member 33 is held between the cylindrical support portion 21 of the
bearing 5 and the inwardly-extending flange portion 28 of the oil
seal cover 9 with the check valve lip 12 resiliently contacting the
outer circumferential surface .Iadd.21a .Iaddend.of the cylindrical
support portion 21.[...]. .Iadd.which serves as seating means for
the annular surface 12a of the check valve lip 12..Iaddend.The
cylindrical support portion 21 of the bearing 5 is provided in the
end section thereof with communication grooves 31 for communicating
the inside and outside of the bearing 5 with each other. A
communication bore 19 is provided in the vicinity of the outer
circumferential surface of the bearing 5 so as to communicate an
outer hollow chamber 17, which is formed on the outer side of the
check valve lip 12, and the gas chamber 3 with each other.
In another embodiment of the present invention shown in FIG. 3, a
bearing 5, which is fitted to end portion of an oil cylinder 1 and
a gas tube 2 to form a gas chamber 3 between the oil-cylinder 1 and
gas tube 2, and an oil chamber 6 between the oil cylinder 1 and a
rod 4, and which supports the rod 4, is provided with a cylindrical
support portion 21 on the opposite side of the oil chamber 6, which
support portion 21 extends in the axial direction of the bearing 5.
An oil seal 10 .Iadd.has integral body means which is 10a
.Iaddend.is reinforced by an annular reinforcing member 33
consisting of a metal sheet and having a substantially Z-shaped
longitudinal section. The oil seal 10 is made of a rubberlike
elastic material, and consists of a main lip 25, a substantially
frusto-conical check valve lip 12, and a sealing and fixing portion
34, which is provided at an outer circumferential end of the oil
seal 10. The sealing and fixing portion 34 is inserted into an
annular groove provided in an outer circumferential end portion of
the bearing 5, and an end portion of the gas tube 2 is bent to form
an inwardly-extending flange portion 28 in order to fix the sealing
and fixing portion 34, reinforced by the annular reinforcing member
33 thereto. Thus, the main lip 25 is brought into resilient contact
with a circumferential surface of the rod 4, and the check valve
lip 12 with the circumferential surface .Iadd.21a .Iaddend.of the
cylindrical support portion 21, respectively, to form inner and
outer hollow chambers 16, 17 between the oil seal 10 and bearing 5.
The hollow chamber 16 communicates with the oil chamber 6. A
radially-extending portion 24, which is formed between the main lip
25 and check valve lip 12, contacts at its inner surface the end
surface of the cylindrical support portion 21. The cylindrical
support portion 21 is provided in its end portion with
communication grooves 31, and communication bores 19 opened into
the gas chamber 3 are provided in the vicinity of an outer end
portion of the bearing 5.
During an upward stroke of the rod 4 in the shock absorber
according to the present invention constructed as described above,
the oil flowing out to the side of the oil seal 10 through a
clearance between the bearing 5 and rod 4 is prevented from leaking
outside by the main lip 25. The oil thereby flows through the
communication grooves 31 to reach the check valve lip 12 and expand
the same. Consequently, the oil flows into the gas chamber 3
through the outer hollow chamber 17 and communication bores 19.
During a downward stroke of the rod 4, the pressures in the inner
hollow chamber 16 and oil chamber 6 decrease, so that the check
valve lip 12 is brought into press contact with the circumferential
surface .Iadd.21a .Iaddend.of the cylindrical support portion 21.
Accordingly, the pressure gas can be prevented from flowing out
.[.to the side of.]. .Iadd.of chamber 3 into .Iaddend.the inner
hollow chamber 16.[...]. .Iadd.which communicates with the oil
chamber 6 through the aforementioned rod clearances. .Iaddend.
The shock absorber according to the present invention having the
above-mentioned construction permits obtaining the following
effects. A bearing adapted to guide a reciprocatingly movable rod
is provided with a cylindrical support portion, and an oil seal has
a main lip, which is adapted to slide on a circumferential surface
of the rod and prevent the leakage of an oil, and a check valve lip
contacting a circumferential surface of the cylindrical support
portion. The oil seal is held at its reinforced portion between the
bearing and the inwardly-extending flange portion provided at the
end portion of the gas tube with an intermediate portion between
the main lip and check valve lip contacting he cylindrical support
portion. Therefore, the oil seal can be maintained in a firmly-held
state. There is no possibility at all that the reciprocating
movements of the rod will adversely affect the sealing functions of
the main lip or check valve lip. Since the bearing is provided with
the cylindrical support portion, an oil reservoir is formed in an
inner hollow chamber, so that the bearing and main lip can be kept
in an excellently-lubricated state with respect to the
reciprocating movements of the rod.
The present invention is not, of course, limited to the above
embodiments; it may be modified in various ways within the scope of
the appended claims.
* * * * *