Patent ID: 9677639
Date: 2017-06-13
CPC Classifications: F15B,F16F

Claim:
1. A bidirectional shock absorber comprising: a cylinder housing including therein a liquid chamber filled with a liquid; a rod having an end portion located inside the liquid chamber and the other end portion liquid-tightly sticking out of the liquid chamber to outside of the cylinder housing, the rod being disposed so as to reciprocate in an axial direction; and a shock-absorbing mechanism located inside the liquid chamber and supported by the rod, the shock-absorbing mechanism being configured to shock-absorbingly stop a relative movement between the cylinder housing and the rod originating from an external force relatively exerted on the cylinder housing and the rod in a pressing direction or a pulling direction, wherein the shock-absorbing mechanism includes: a first and a second piston which are able to be displaced separately in the axial direction on the rod by the action of liquid pressure, and which are supported by the rod at different positions in the axial direction; a first and a second piston chamber respectively defined by the first and the second piston; a liquid storage chamber formed between the first piston and the second piston; resistance paths respectively formed between an outer circumferential surface of the first and the second piston and an inner circumferential surface of the liquid chamber, the resistance paths being configured to apply flow resistance to the liquid; and a first and a second unidirectional flow path respectively connecting between the first and the second piston chamber and the liquid storage chamber, the first and the second unidirectional flow paths are openable and closable by displacement of the first and the second pistons with respect to the rod and, when the rod is reciprocating, one of the unidirectional flow paths located ahead of the rod in the moving direction is closed by displacement, with respect to the rod, of the respective piston located on the forward side in the moving direction, so as to block the flow of the liquid flowing from the piston chamber on the forward side in the moving direction toward the liquid storage chamber, and that the other unidirectional flow path located behind the rod in the moving direction is opened by displacement, with respect to the rod, of the respective piston located on the rear side in the moving direction, so as to allow the liquid to flow from the liquid storage chamber to the piston chamber on the rear side in the moving direction.