US 12,305,732 B2
Shock absorber
Milton Muzvidziwa, Hitachinaka (JP); Koichi Yamaka, Hitachinaka (JP); and Yohei Katayama, Hitachinaka (JP)
Assigned to HITACHI ASTEMO, LTD., Ibaraki (JP)
Appl. No. 17/791,773
Filed by Hitachi Astemo, Ltd., Hitachinaka (JP)
PCT Filed Jan. 20, 2021, PCT No. PCT/JP2021/001831
§ 371(c)(1), (2) Date Jul. 8, 2022,
PCT Pub. No. WO2021/149718, PCT Pub. Date Jul. 29, 2021.
Claims priority of application No. 2020-010063 (JP), filed on Jan. 24, 2020.
Prior Publication US 2023/0037408 A1, Feb. 9, 2023
Int. Cl. F16F 9/34 (2006.01); F16F 9/19 (2006.01); F16F 9/32 (2006.01); F16F 9/46 (2006.01)
CPC F16F 9/3271 (2013.01) [F16F 9/19 (2013.01); F16F 9/34 (2013.01); F16F 9/46 (2013.01); F16F 2222/12 (2013.01); F16F 2228/066 (2013.01); F16F 2232/08 (2013.01); F16F 2234/02 (2013.01)] 15 Claims
OG exemplary drawing
 
1. A damping force adjustable shock absorber comprising:
a cylinder sealingly containing hydraulic fluid therein;
a piston slidably fitted in the cylinder and partitioning an inside of the cylinder into two chambers;
a piston rod having one end coupled with the piston and an opposite end extending out of the cylinder;
an extension-side passage and a compression-side passage provided in the piston;
a piston bolt inserted through an axial hole of the piston;
an extension-side main valve provided in the extension-side passage;
an extension-side backpressure chamber configured to adjust a valve-opening pressure of the extension-side main valve;
a compression-side main valve provided in the compression-side passage;
a compression-side backpressure chamber configured to adjust a valve-opening pressure of the compression-side main valve;
a common passage configured to establish communication between the extension-side backpressure chamber and the compression-side backpressure chamber;
a valve shaft movably provided in the common passage;
a spring fixation member fixed to the valve shaft;
a pilot valve configured to control a flow of hydraulic fluid in the common passage and provided at the distal end side of the valve shaft, the pilot valve including a valve body;
a valve spring configured to bias the pilot valve of the valve shaft in a valve-opening direction and to bias the spring fixation member fixed to the valve shaft, and
an actuator configured to control the movement of the valve shaft,
wherein a first valve portion is provided at one axial end of a valve body of the valve shaft, the first valve portion being configured to restrict a flow of the hydraulic fluid between the first valve portion and a first valve seat formed on the piston bolt when no power is supplied to the actuator,
wherein a second valve portion is provided at an opposite axial end side of the valve body, the second valve portion being configured to restrict a flow of the hydraulic fluid between the second valve portion and a second valve seat formed on the piston bolt when power is supplied to the actuator,
wherein the piston bolt includes a first member and a second member,
wherein the first valve seat is formed on the first member, and
wherein the second valve seat is formed on the second member.