Patent ID: 6078155
Filing Date: 2000-06-20
Classification: B62D,H05K

Abstract:
An electric power steering circuit assembly comprising:a motor for outputting an auxiliary torque to a steering wheel of an automobile;a battery for supplying a motor current to drive said motor;a torque sensor for detecting the steering torque of said steering wheel;a vehicle speed sensor for detecting the vehicle speed of said automobile;a power circuit board mounted with a bridge circuit comprising a plurality of semiconductor switching components for switching said motor current according to the required auxiliary torque;a housing having conductor strips insert-molded in insulating resin to form wiring patterns, having a connector for electrical connection to said motor and said battery formed integrally therein, and being mounted with capacitors for absorbing ripple components in said motor current, a coil for preventing the external emission of noise generated by said bridge circuit during said switching operation, a power source relay for connecting and disconnecting said motor current supplied from said battery to said bridge circuit, and a motor relay for connecting and disconnecting said motor current supplied from said bridge circuit to said motor;a control circuit board mounted with a microcomputer and peripheral circuit components for generating a drive signal for controlling said bridge circuit based on said steering torque of said steering wheel and said vehicle speed of said automobile;connecting members disposed in an upright position on said power circuit board having a plurality of terminals for the electrical connection of said power circuit board to said housing and to said control circuit board; anda heat sink,said electric power steering circuit assembly having a layered construction such that said power circuit board is secured in close contact to said heat sink, said housing is secured to said heat sink so as to cover said power circuit board, and said control circuit board is secured to said housing so as to overlap said power circuit board in a vertical direction, andhaving guides formed in said housing for receiving said connecting members and positioning said housing relative to said power circuit board.