POWER STEERING DEVICE

PROBLEM TO BE SOLVED: To provide a power steering device capable of suppressing the noise generated by excessive flow of a working fluid in a back pressure regulating valve provided on a pump when a steering wheel is shifted from the strike (end of a cut-in state) to the return. SOLUTION: The power steering device comprises a power cylinder 2 for supporting the operational force of a steering mechanism, a hydraulic pump 24 for feeding the hydraulic pressure to the power cylinder, first and second oil passages for respectively connecting the power cylinder and the hydraulic pump to each other, a motor 20 for driving the hydraulic pump, and a power steering control means 17 for calculating the command value to the motor based on the steering torque. When the steering mechanism is transferred from the end of the cut-in state (strike) to the return, the flow rate of the working fluid to be fed from an oil passage 27b on the high-pressure side to an oil passage 27a on the low-pressure side is suppressed. The flow rate is suppressed by increasingly correcting the driving current in the cut-in direction of the motor, or limiting the flow rate of the working fluid. COPYRIGHT: (C)2007,JPO&INPIT