Hydraulic reaction force apparatus of power steering device

Claim 1

A hydraulic reaction force apparatus of a power steering device, comprising: an input shaft; an output shaft; means for providing direct torsional coupling between said input shaft and said output shaft; and means for providing a variable drag force in opposition to said direct torsional coupling means, said drag force means including: reaction force arms, connected integrally with said input shaft, and projecting radially therefrom; a pair of output shaft guide holes, sandwiching each of said reaction force arms, and oppositely disposed to each other in a direction perpendicular to said reaction force arms; a plurality of reaction force plungers each slidably disposed in a corresponding different one of said guide holes; and means for providing a hydraulic force for biasing said reaction force plungers against said reaction force arms to oppose relative rotation between said output shaft and said input shaft; each of said reaction force plungers comprising a metal cylindrical member having a hollow portion open at a side opposite to that of said reaction force arms; and a damping member carried by said cylindrical member, said damping member having an inner end, an outer end and means for exposing said inner end and said outer end to said hydraulic force.