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.

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.