Hydraulic valve device for automotive power steering gear

Abstract

A power steering device for a motor vehicle whereby when the vehicle is under a high or middle speed movement, the slide torque is controlled to a relatively low constant level irrespective of the turning of the steering wheel. The device includes a hydraulic pump for producing a hydraulic pressure; a power cylinder powered by the hydraulic pressure for producing a force to assist the steering job; a hydraulic valve for controlling the hydraulic pressure supplied to the power cylinder, the hydraulic valve including a valve shaft and a valve body; a chattering protection seal associated with the hydraulic valve to assure a concentric rotation of the valve shaft relative to the valve body with an assistance of hydraulic pressure applied thereto; and an electronically controlled solenoid valve. The electronically controlled solenoid valve applies when the vehicle is at a standstill or under a low speed movement, the chattering protection seal with a hydraulic pressure which is varied as a steering wheel is turned, and applies, when the vehicle is under a high or middle speed movement, the chattering protection seal with a hydraulic pressure which is controlled to a relatively low constant level even when the steering wheel is turned.

Dependencies are inferred from the claim text.