Patent ID: 8584791

Claim:
A hydraulic power steering apparatus for assisting in steering of a vehicle with a hydraulic cylinder, the apparatus comprising: a flow control valve capable of changing a supply/drainage amount of hydraulic fluid for the hydraulic cylinder; a detecting device that detects an operating state of a vehicle; and a control section that sets a supply/drainage mode of the hydraulic fluid for the hydraulic cylinder based on a detection result of the detecting device and that controls the flow control valve in correspondence with the supply/drainage mode, wherein the interior of the hydraulic cylinder is divided into a first hydraulic chamber and a second hydraulic chamber by a piston formed on a rack shaft, the flow control valve includes: a housing, wherein a supply port through which the hydraulic fluid is supplied, a drainage port through which the hydraulic fluid is drained, a first port connected to the first hydraulic chamber, and a second port connected to the second hydraulic chamber are formed in an outer peripheral surface of the housing, the ports being arranged at different positions in a circumferential direction of the housing; a valve portion rotatably received in the housing, the valve portion switching a communication state of each of the ports between a first mode in which the supply port communicates with the first port and the drainage port communicates with the second port and a second mode in which the supply port communicates with the second port and the drainage port communicates with the first port; and a motor that rotates the valve portion about the axis of the housing, and the control section switches between the first mode and the second mode and adjusts a supply/drainage amount of the hydraulic fluid for the first and second ports in the first mode and the second mode by adjusting a rotating amount of the valve portion in correspondence with the supply/drainage mode of the hydraulic fluid.