| 摘要 |
PURPOSE:To stabilize relief operation and save energy of a power source for a hydraulic pump by giving hysteresis function to a relief valve provided in a pipe path interconnecting the hydraulic pump and an actuator. CONSTITUTION:A power steering gear is constructed to supply pressurized oil from a hydraulic pump 5 to an actuator 6 through a pipings 9, 9' and a control valve 2 when a steering wheel 1 is rotated. The pipes 9, 9' are provided with relief valve 10 having a line port 11 and a tank port 16. A first relief portion 20 is provided adjacent the line port 11 and a second relief portion 21 is provided to be connected to the first relief portion 20. A ball 14 urged through a guide 17 by a spring 18 is received by the first relief portion 20. Thus, the pressure of the hydraulic pump can be lowered to the allowable limit of steerage holding force by giving hysteresis function to the relief operation. |
