Patent ID: 6349788
Filing Date: 2002-02-26
Classification: B62D,Y10T

Abstract:
A power steering apparatus includinga control valve for controlling a change-over of a pump side supply passage and a tank side return passage with respect to a first chamber and a second chamber of a power cylinder in accordance with a steering operation, the control valve comprising: a sleeve; and a rotary spool fitted into the sleeve, the sleeve and the rotary spool being coaxially arranged so as to be relatively displaceable in accordance with a steering torque, the sleeve having a supply port connected to the pump side supply passage, and first and second ports which are connected individually to the first and second chambers of the power cylinder and are arranged around a central axis so as to be symmetrical with respect to an axial point, the rotary spool having a return port which is connected to the tank side return passage and is arranged around a central axis so as to be symmetric with respect to an axial point, wherein in a state of assembling the sleeve and the rotary spool, each longitudinal groove extends in a valve axial direction being formed at an inner surface of the sleeve so that adjacent ports of the sleeve and the rotary spool communicate with each other, with each upper end of the adjacent longitudinal grooves being arranged in a stagger layout.