Hydraulic control apparatus for a power steering device

Abstract

In a handle steering force control mechanism adapted to stabilize steering feeling of a steering handle by imparting hydraulic reaction to a power steering device when the vehicle is travelling at high speed, a hydraulic control apparatus for supplying stabilized pressure oil to the power steering device and a hydraulic reaction chamber. This hydraulic control apparatus comprises a main spool and a sub-spool slidably inserted into the main spool to form a variable throttle whose open area is varied by relative displacement therebetween. This variable throttle, when the vehicle travels at high speed, closes the main valve side by the sub-spool and opens the hydraulic reaction side to increase reaction pressure. When reaction pressure reaches a predetermined value in response to steering pressure, the main spool is displaced by pressure oil to cut the reaction pressure.