Patent ID: 7021418

Claim:
An electric power steering apparatus including an electric motor for generating assist torque to a steering wheel of a vehicle, and a control unit for controlling the driving of said electric motor, said control unit comprising: a power board having a bridge circuit mounted thereon which includes a plurality of semiconductor switching elements for switching an electric current supplied to said electric motor in accordance with the torque assisting the operation of said steering wheel; a capacitor mounted on said power board for absorbing ripples of the electric current; a control board at least having a microcomputer mounted thereon for generating a drive signal to control said bridge circuit based on steering torque of said steering wheel; a power connector electrically connected to a battery of the vehicle; a signal connector unit to and from which signals are input and output through external wiring; motor terminals electrically connected to said electric motor; a housing having a conductive plate constituting a wiring pattern and said motor terminals insert-molded of an insulation resin; a connection member mounted on said power board and having a plurality of terminals built therein for electrically connecting said power board, said housing and said control board to one another; and a heat sink disposed on said power board in surface contact therewith; wherein said heat sink has a plurality of protrusions formed on its surface at a side opposite to said power board, wherein said capacitor is fixedly attached to said housing by means of an adhesive, and wherein said housing has a beam for reinforcement formed in the neighborhood of said capacitor, and said capacitor is fixedly attached to said beam.