US 12,247,638 B2
Fluid pressure shock absorber
Hiroshi Funato, Gifu (JP); Tomoo Kubota, Kanagawa (JP); Masaya Omote, Kanagawa (JP); and Yuuta Furukawa, Kanagawa (JP)
Assigned to KYB CORPORATION, Tokyo (JP)
Appl. No. 17/414,630
Filed by KYB Corporation, Tokyo (JP)
PCT Filed Dec. 5, 2019, PCT No. PCT/JP2019/047709
§ 371(c)(1), (2) Date Jun. 16, 2021,
PCT Pub. No. WO2020/129682, PCT Pub. Date Jun. 25, 2020.
Claims priority of application No. 2018-236564 (JP), filed on Dec. 18, 2018.
Prior Publication US 2022/0065324 A1, Mar. 3, 2022
Int. Cl. F16F 9/32 (2006.01); F16F 9/516 (2006.01)
CPC F16F 9/516 (2013.01) [F16F 9/3228 (2013.01)] 9 Claims
OG exemplary drawing
 
1. A fluid pressure shock absorber, comprising:
a cylinder tube;
a piston rod extending outward from inside of the cylinder tube and having a first end and a second end opposite to each other in an axial direction of the piston rod, the piston rod having a rod internal space therein, the piston rod having a rod head provided at the first end of the piston rod;
a piston provided at the second end of the piston rod, the rod internal space being bounded at opposite ends thereof respectively by the rod head and the piston, the piston slidably moving inside the cylinder tube with the piston rod and dividing a space inside the cylinder tube into a piston-side chamber and a rod-side chamber;
a first communication passage communicating the rod-side chamber with the rod internal space;
a second communication passage formed in the piston and communicating the piston-side chamber with the rod internal space;
a restrictor provided in the second communication passage to apply a resistance to a flow of a working fluid passing through the second communication passage;
a third communication passage formed in the piston and communicating the piston-side chamber with the rod internal space; and
a check valve provided in the third communication passage to allow only a flow of the working fluid from the piston-side chamber to the rod internal space, wherein
the rod internal space, bounded at the opposite ends respectively by the rod head and the piston, consists of a single continuous space within the piston rod,
a resistance applied to a flow of the working fluid passing through the first communication passage is smaller than the resistance applied by the restrictor to the flow of the working fluid passing through the second communication passage, and
the shock absorber is configured to generate a damping force by extending or contracting, and while the shock absorber is extended and a pressure in the rod-side chamber and the rod internal space rises above a pressure in the piston-side chamber, the check valve is closed and the working fluid in the rod-side chamber and the rod internal space flows into the piston-side chamber only through the second communication passage.