# US 7,611,000 B2 · Damping force adjusting structure of hydraulic shock absorber > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 7,611,000 B2 - Document ID: US7611000B2 - Status: Granted - Kind: B2 - Application number: 12/074,967 - Filed: 2008-03-07 - Published: 2009-03-19 - Granted: 2009-11-03 - Earliest claimed: 2007-09-14 - Assignees: Showa Corporation - Inventors: Tutomu Naito - Web page: https://patentgrep.com/patent/US7611000B2 ## CPC - F16F 9/465: {using servo control, the servo pressure being created by the flow of damping fluid, e.g. controlling pressure in a chamber downstream of a pilot passage (self-adjustment of damping F16F9/50)} - F16F: SPRINGS; SHOCK-ABSORBERS; MEANS FOR DAMPING VIBRATION ## Abstract In a damping force adjusting structure of a hydraulic shock absorber in which a part of an oil liquid is introduced to a back pressure chamber provided in a back surface side of a damping valve from a back pressure introduction path, a pressure within the back pressure chamber is leaked from a leak path, and a damping force can be adjusted by controlling a valve opening pressure of the damping valve by controlling the pressure in the back pressure chamber. A leaf valve with slit is provided in the back pressure introduction path, and a slit provided in the leaf valve with slit is formed as an introduction side orifice. ## Claims ### Claim 1 A damping force adjusting structure of a hydraulic shock absorber in which an oil liquid is accommodated in a cylinder, a piston provided in an insertion end of a piston rod inserted to the cylinder is slidably fitted and inserted to the cylinder, a damping force is generated by controlling an oil liquid flow generated by a sliding motion of the piston by a damping valve, a part of the oil liquid is introduced to a back pressure chamber provided in a back surface side of the damping valve from a back pressure introduction path, a pressure within the back pressure chamber is leaked from a leak path, and the damping force is adjustable by controlling a valve opening pressure of the damping valve by controlling the pressure in the back pressure chamber, wherein said back pressure introduction path is provided in the piston rod, a leaf valve with a slit is provided at an inlet of said back pressure introduction path, and said slit is formed as an introduction side orifice. ### Claim 2 (depends on 1) A damping force adjusting structure of a hydraulic shock absorber according to claim 1, wherein a valve stopper is provided in a back surface of said damping valve, a backup collar sliding via a sliding gap forming the leak path is provided in an outer periphery of the valve stopper, a spring is provided in a back surface of the backup collar, and the back pressure chamber is formed by pressing a front surface of the backup collar to the damping valve by the spring, and wherein a seal ring with which the backup collar comes into slidable contact is provided in the outer periphery of the valve stopper, and a leak side orifice forming a part of the leak path is provided in the seal ring. ### Claim 3 (depends on 2) A damping force adjusting structure of a hydraulic shock absorber according to claim 2, wherein said spring is constituted by a leaf spring, and is provided with a base portion fixed to the back surface side of the valve stopper, and a tongue portion protruding from a plurality of positions in an outer periphery of the base portion so as to press the back surface of the backup collar. ### Claim 4 (depends on 3) A damping force adjusting structure of a hydraulic shock absorber according to claim 3, wherein said leaf valve with slit is formed as a laminated shape having a plurality of thin plates, and said leaf valve is structured by forming a slit at one position or a plurality of positions in a circumferential direction of an outer edge of the thin plate in the lowest layer side facing to the back pressure introduction path. ### Claim 5 (depends on 4) A damping force adjusting structure of a hydraulic shock absorber according to claim 4, wherein an inner side of the cylinder is compartmentalizeded into a rod side chamber and a piston side chamber by said piston, said back pressure introduction path communicates a slit of said leaf valve with slit, a vertical groove provided in an insertion end of the piston rod, and a horizontal hole provided in said valve stopper in sequence, and is formed in such a manner as to open the slit of the leaf valve with slit to the rod side chamber and open the horizontal hole to the back pressure chamber. ### Claim 6 (depends on 3) A damping force adjusting structure of a hydraulic shock absorber according to claim 3, wherein an inner side of the cylinder is compartmentalizeded into a rod side chamber and a piston side chamber by said piston, said back pressure introduction path communicates a slit of said leaf valve with slit, a vertical groove provided in an insertion end of the piston rod, and a horizontal hole provided in said valve stopper in sequence, and is formed in such a manner as to open the slit of the leaf valve with slit to the rod side chamber and open the horizontal hole to the back pressure chamber. ### Claim 7 (depends on 2) A damping force adjusting structure of a hydraulic shock absorber according to claim 2, wherein said leaf valve with slit is formed as a laminated shape having a plurality of thin plates, and said leaf valve is structured by forming a slit at one position or a plurality of positions in a circumferential direction of an outer edge of the thin plate in the lowest layer side facing to the back pressure introduction path. ### Claim 8 (depends on 7) A damping force adjusting structure of a hydraulic shock absorber according to claim 7, wherein an inner side of the cylinder is compartmentalizeded into a rod side chamber and a piston side chamber by said piston, said back pressure introduction path communicates a slit of said leaf valve with slit, a vertical groove provided in an insertion end of the piston rod, and a horizontal hole provided in said valve stopper in sequence, and is formed in such a manner as to open the slit of the leaf valve with slit to the rod side chamber and open the horizontal hole to the back pressure chamber. ### Claim 9 (depends on 2) A damping force adjusting structure of a hydraulic shock absorber according to claim 2, wherein an inner side of the cylinder is compartmentalized into a rod side chamber and a piston side chamber by said piston, said back pressure introduction path communicates a slit of said leaf valve with slit, a vertical groove provided in an insertion end of the piston rod, and a horizontal hole provided in said valve stopper in sequence, and is formed in such a manner as to open the slit of the leaf valve with slit to the rod side chamber and open the horizontal hole to the back pressure chamber. ### Claim 10 (depends on 1) A damping force adjusting structure of a hydraulic shock absorber according to claim 1, wherein said leaf valve with slit is formed as a laminated shape having a plurality of thin plates, and said leaf valve is structured by forming a slit at one position or a plurality of positions in a circumferential direction of an outer edge of the thin plate in the lowest layer side facing to the back pressure introduction path. ### Claim 11 (depends on 10) A damping force adjusting structure of a hydraulic shock absorber according to claim 10, wherein an inner side of the cylinder is compartmentalizeded into a rod side chamber and a piston side chamber by said piston, said back pressure introduction path communicates a slit of said leaf valve with slit, a vertical groove provided in an insertion end of the piston rod, and a horizontal hole provided in said valve stopper in sequence, and is formed in such a manner as to open the slit of the leaf valve with slit to the rod side chamber and open the horizontal hole to the back pressure chamber.