PURPOSE: To reduce the sliding resistance of a valve body and consequently improve the steering feeling of a vehicle by a structure wherein the valve body is loosely fitted on a seal housing floatingly supported in a valve body.
CONSTITUTION: A tubular seal housing 8 is concentrically and floatingly supported through rubber elastic O-rings 13 in a valve housing 12 and a tubular valve body 11 is fitted in the seal housing 8 with the allowable clearance interposed therebetween. The valve body 11 rotates within the valve housing 12 so as to control the flow rate of the pressure oil to a steering gear. However, because at this time the rotation of the valve body 11 is not followed by the rotation of the seal O-rings 13, the sliding resistance of the valve body 11 becomes small.