Patent ID: 8448759
Filing Date: 2013-05-28
Classification: B60G,F16F

Abstract:
1. A single cylinder type hydraulic shock absorber for a vehicle, which is interposed between a vehicle body and an axle of the vehicle to suppress vibration in the vehicle body, the shock absorber comprising: a cylinder; a free piston slidably disposed within the cylinder and delimiting a fluid chamber and a gas chamber in the cylinder, wherein a pressurized gas is sealed in the gas chamber; a fluid piston that is slidably disposed in the cylinder and delimits the fluid chamber into an expansion side pressure chamber and a contraction side pressure chamber; a rod connected to the fluid piston; a passage that is provided in the fluid piston and connects the expansion side pressure chamber and the contraction side pressure chamber; a damping force generating element that is interposed in the passage and applies resistance to a flow of fluid through the passage; and an elastic member disposed within the gas chamber and biasing the free piston towards the fluid chamber, wherein via the free piston, the contraction side pressure chamber is pressurized directly by a gas pressure in the gas chamber and a reaction force of the elastic member, the elastic member is set such that a spring constant thereof increases during contraction so as to bias the free piston so that the free piston at no time moves in parallel with the fluid piston during an entire contraction stroke of the hydraulic shock absorber, the elastic member having a small spring constant site and a large spring constant site that has a spring constant greater than that of the small spring constant site.