Patent ID: 7635046
Filing Date: 2009-12-22
Classification: B62D,H02K,H05K

Abstract:
1. An electric power steering apparatus including an electric motor for outputting assist torque to a steering wheel of a vehicle, and a control unit for controlling the driving of said electric motor, wherein said control unit comprises: a power main body including a plurality of semiconductor switching elements for switching a current supplied to said electric motor in accordance with torque assisting said steering wheel, and a plurality of high current parts including capacitors for absorbing ripples of said current; a control main body that includes a plurality of low current parts including a microcomputer for generating drive signals to control the driving of said semiconductor switching elements based on the steering torque of said steering wheel; a circuit board that has a plurality of insulating layers and a plurality of conductor layers forming wiring patterns laminated one over another, and a plurality of through holes formed therethrough, with said power main body and said control main body being mounted thereon; and a heat sink that receives said circuit board and is made of a metal material of high conductivity; and wherein said high current parts and said low current parts are mounted on the opposite side surfaces of said circuit board, respectively, and are electrically connected with one another through said conductor layers and said through holes.