| 摘要 |
PURPOSE: To improve operation stability and comfortableness performance by providing a valve member which keeps a fluid passage under an opened condition by energization force, and which is actuated to set the fluid passage in a closed condition by hydraulic force against the energization force when the hydraulic force to a power steering device exceeds a specified value. CONSTITUTION: In the case where an axle is not steered, hydralic force of a power steering device 33 is not increased, but it is a specified value or less. In this condition, a spool valve 20 is moved by energization force of a compression coil spring 22 to communicate a valve chamber 18 with a pair of liquid chambers 16 through a communication groove 21 and a fluid passage 19 to allow flow of oil between the liquid chambers 16. Rigidity of a rubber bush 12 is thus decreased to provide proper damping performance to absorb forward/ back input from low speed to high speed. When a vehicle is steered, the hydraulic force of the power steering device is increased to exceed a specified value, when the spool valve 20 is moved to close the liquid passage 19 to form an oil locked condition, where rigidity of the rubber bush 12 is increased. |
