| 摘要 |
<p>Vehicles having front and rear pairs of steerable wheels are sometimes provided with large springs for moving one pair of the wheels to a straight-ahead position during emergency steering. Large amounts of hydraulic energy are expended solely for the compression of such springs every time the pair of wheels are steered. A back-up steering control system (19) of the present steering control arrangement (10) has a servo valve (76) operative to control the flow of pressurized fluid from a back-up pump (60) to a steering control valve (21) which in turn controls the flow of pressurized fluid from the back-up pump to a hydraulic actuator (13) to hydraulically move a first pair of steerable wheels (11) to a straight-ahead position during emergency steering conditions. A manual control valve (68) is operative to control the flow of pressurized fluid from the back-up pump (60) to another steering control valve (22) which in turn controls the flow of pressurized fluid to a hydraulic actuator (16) for effecting steering of a second pair of steerable wheels (12) during the emergency steering condition.</p> |
