| 摘要 |
Apparatus and method for motor-driven power-assisted steering for a vehicle, which make it possible to avoid as much as possible frequent operations of engaging and disengaging an electromagnetic clutch 14 which connects a motor 13 to a steering system or disconnects it from the latter, thus improving the durability of the clutch 14 and eliminating the annoying impacts and the noise during connection or disconnection of the clutch 14. The supply to the motor 13 is interrupted by a motor control device 191, when the speed V of the vehicle is equal to or greater than a predetermined value Vo. The clutch 14 is disengaged in order to disconnect the motor from the steering system when an anomaly is detected in the steering system, the vehicle driving at high speed. Such an anomaly is detected if the motor current which flows through the non-powered motor is not equal to zero, or if the steering torque is equal to or greater than a predetermined value and if the voltage at the terminals of the motor, when the latter is not powered, is equal to zero, or if the speed of rotation of the steering wheel is equal to or greater than a predetermined value and if the voltage at the terminals of the motor is equal to zero. <IMAGE>
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