| 摘要 |
<p>A hydraulic servo steering system (10) for vehicles has a steering valve (24) for directing fluid to steering cylinders (16, 17) in response to pilot fluid directed to one end of the steering valve (24) from a hand metering unit (31). A servo cylinder (19) directs a volume of fluid to the other end of the steering valve (24) sufficient for returning the steering valve (24) to its centered position in response to turning of the vehicle. A pair of pilot operated check valves (53, 54) positioned in the lines (51 52) between the servo cylinder (19) and the steering valve (24) are opened in response to fluid pressure being established in the lines (51, 52) by a means (71). Should one of the lines (51, 52) rupture, the resultant drop in fluid pressure in the lines (51, 52) causes the check valves (53, 54) to close thereby isolating the steering valve (24) from the ruptured lines (51, 52). Thereafter the steering valve (24) can be operated in a "jerk steer" manner for emergency steering of the vehicle. </p> |
