1. Field of the Invention
The present invention relates to an electric power steering apparatus for reducing a steering effort on the steering wheel by torque of a motor.
2. Related Background Art
There existed the conventional electric power steering apparatus among power steering devices for reducing the steering effort on the steering wheel. The electric power steering apparatus was arranged to detect steering torque by a torque sensor and to transmit assist force generated by the motor, based on the steering torque thus detected, through an electromagnetic clutch and a reducing unit to a steering shaft, for example, as disclosed in Japanese Laid-open Utility Model Application No. 62-13764.
In the electric power steering apparatus described above, however, the motor was connected through the reducing unit to the steering shaft, and thus the motor was an inertial object in the steering system. Specifically, the inertia force of the motor, which is sensed by the driver manipulating the steering wheel, is expressed by (moment of inertia of the motor).times.(gear ratio).times.(gear ratio) and is thus greatly affected by the gear ratios. It was, therefore, the cause of degrading the steering feeling.