Abstract: An electronic power steering apparatus according to the present invention uses hypoid gears having a larger gear on a steering assisting motor side and a smaller gear on a pinion shaft side as a transmission device for transmitting a rotational force of the motor to the pinion shaft or a column shaft, thereby reducing a shaft-to-shaft distance required between the motor and the pinion shaft. Further, rack teeth, which have a pressure angle that reduces toward both of the ends of a moving stroke of a rack shaft, are formed on the rack shaft that engages the pinion gear so that an insufficient steering assisting force is supplemented at the stroke ends, that is, at a large steering range; thus, it is possible to miniaturize the motor. Therefore, it becomes possible to reduce a space occupied by the motor on the periphery of the column shaft or the pinion shaft, and consequently to allow easy installation inside the automobile room or the engine room.

Abstract: A power steering apparatus in which a housing to contain a torque sensor for sensing seering torque, a small-sized motor for assisting steering, and a driving device for transmitting driving force of the motor to the steering shaft is made small-sized and disposed on the middle part of the steering shaft in the cab of the car, and, further, pressure angles of rack teeth engaging with a pinion shaft connected to the steering shaft reduce with the advance from the center of the toothed part of the rack to the end thereof so that steering assisting power is increased with the increase in the degree of steering angle.