MOTOR-DRIVEN POWER STEERING SYSTEM.

摘要

The power steering system has a control unit (9), which receives signals from steering torque (2) and vehicle speed (10) sensors and turns a DC motor (13) to provide an auxiliary steering force to a shaft via an electromagnetic clutch (16). A fail-safe relay (91) is provided on a power supply line to the electromagnetic clutch (16). When abnormality occurs in steering torque or vehicle speed, a microcomputer (96) switches off the fail-safe relay so that the electromagnetic clutch is disengaged due to the absence of supplied power. Thus manual steering is retrieved free from motor load.