| 摘要 |
<p>PURPOSE:To obtain a motor-driven power steering device having high reliability at a low cost by constituting the device so that the second switch is turned OFF and a clutch is put into OFF state, when it is judged that the voltage detected by the first or second comparing means is outside a prescribed range. CONSTITUTION:When the number of times of judgement that the terminal voltage VCL is abnormal is within a prescribed value, fail-safe operation is not carried out. When the number of times of judgement that the terminal voltage VCL is abnormal reaches a prescribed value in continuous form, it is judged that the state is not the abnormal state which is generated discretely, and fail- safe operation is carried out, and a microcomputer 12 controls a relay driving circuit, and opens the contact point 39a of a fail-safe relay 39. Then, a clutch is put into OFF state, and a motor and a steering shaft are separated. Then, the drive of the motor is brought into stop, and an alarm lamp is put ON. Accordingly, when the clutch ON is instructed, if the generation of short circuit or breakage of an electromagnetic coil 2 or the grounding or breakage in the circuit with which the electromagnetic coil is connected is detected in continuation, the clutch is put into OFF state.</p> |
