| 摘要 |
<p>An adhesion drive rail vehicle comprises a prime mover (1) and a hydrostatic transmission incorporating a hydraulic motor (10) provided at the or each driven wheel or axle, a variable output pump (21) biased to a drive condition, and at least one throttle valve (3A, 3B) to control vehicle braking, the or each such valve being operable by a disproportional area actuator (2A, 2B). The control circuit incorporates at least one driver operated speed control device (14, 15) movable in a first mode to cause acceleration of the vehicle by sending a variable pressure signal to the pump control means (6) whereby the pump (21) comes on stroke, the device (14, 15) also being movable in a second mode to cause retardation of the vehicle by sending a variable pressure signal to the disproportional area actuator (2A or 2B), to adjust the associated throttle valve (3A or 3B) to induce back pressure in the return line from the motor(s) (10), a feed back loop monitoring the regenerated pressure and permitting the throttle valve to continue to close as the flow through the valve reduces under the influence of the actuator, at a driver selected braking pressure, until the vehicle comes to rest. <IMAGE></p> |
