Abstract: A power steering apparatus in which a motor for assisting steering force is mounted in such a manner that it is positioned substantially in parallel to a rack shaft of a rack-pinion type steering mechanism, and a planetary roller reduction device and a bevel gear connected directly thereto are mounted to the rotary shaft of the motor, coaxially with the motor, whereby the speed of the turning force of the motor may be reduced sufficiently and thus decelerated turning force is transmitted to the rack shaft, to permit compact disposing of the motor and the reduction device around the steering mechanism. In one embodiment of the invention the motor is mounted below the rack shaft and in another above the rack shaft between the steering wheel and the rack shaft.

Abstract: A power steering apparatus in which a motor for assisting steering force is mounted in such a manner that it is positioned substantially in parallel to a rack shaft of a rack-pinion type steering mechanism, and a planetary roller reduction device and a bevel gear connected directly thereto are mounted to the rotary shaft of the motor, coaxially with the motor. The speed of the turning force of the motor is reduced sufficiently and thus decelerated turning force is transmitted to the rack shaft, to permit compact disposing of the motor and the reduction device around the steering mechanism.

Abstract: A steering force control apparatus for a power steering apparatus of a vehicle of the type having a reaction chamber responsive to fluid pressure applied thereto for producing a reaction force to counteract the steering force produced by a power cylinder. A main tubular spool is disposed in a valve case movably relative to the valve case and has an inner valve surface. A sub-spool is disposed in the main spool movably relative to the main spool and has an outer valve surface cooperative with the inner valve surface to define a variable throttle for selectively connecting a fluid pump to the reaction chamber and to the power cylinder according to the movement of the sub-spool relative to the main spool in response to the vehicle speed. The main spool is moved relative to the valve case and the sub-spool in response to the fluid pressure applied to the reaction chamber when the fluid pressure is above a certain value to enable the variable throttle to disconnect the fluid pump from the reaction chamber.

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.