Power steering device

摘要

The present invention provides a power steering device which can effectively reduce the operating force of a steering wheel and shorten the time from a release of the operating force to return of a vehicle to a straight traveling state. The device has a hydraulic pump 28, a power cylinder 30, a control valve 32 interposed therebetween, and a bypass line 50. The control valve 32 operates in synchronization with a steering wheel operation so as to be shifted between a communication position 42C for communicating cylinder chambers 36L and 36R of the power cylinder 30 with a tank 40, and a left-side supply position 42L and a right-side supply position 42R for introducing discharge oil of the hydraulic pump 28 to the cylinder chamber corresponding to the direction of the operation. The bypass line 50 bypasses the control valve 32 to allow hydraulic oil to flow from the expanded cylinder chamber to the contracted cylinder chamber, when the control valve 32 returns from either the supply position to the communication position.