| 摘要 |
<p>PURPOSE:To prevent an uncontrollable condition caused by the abnormal operation of rear wheels due to failures so as to make running possible after the failures with front wheels steered correctively by inserting a fail safe relay having a normally open contact on the halfway of an electric power supply line whereby operating the same. CONSTITUTION:A control unit 20 outputs driving signals to a motor 24 and an electromagnetic brake 25 based on input signals from a rear wheel steering angle sensor 23, a motor revolving speed sensor 27, and a steering condition sensor 21. And the unit 20 contains a fail safe relay 201 wherein a normally open contact 201b with a driving coil 201a is contained. When no rear wheel steering is required because failures occur in any of respective sensors, wirings among sensors, or in the control unit whereby allowing free steering of rear wheels, the coil 201 a is interrupted based on the judgement made by a computer 204 for opening the contact 201b so as to lock the rear wheels at a position where the failures occur.</p> |
