| 摘要 |
<p>A load sensing priority flow control system is disclosed of the type including an engine-driven pump (11), a load sensing priority flow control valve (15), a priority load circuit (steering control valve (17) and steering cylinder (21)), and an auxiliary load circuit (19). Disposed between the excess flow output port (45) of the priority valve and the auxiliary load circuit (19) is a bypass valve arrangement (55) including a bypass valve member (57) which is biased by a downstream pressure signal (61) and spring (63) to a first position in which the auxiliary load circuit is communicated to the reservoir, to prevent loading the system and stalling the engine when the engine speed and flow from the excess flow port (45) are below a predetermined minimum. As engine speed and flow from the port (45) increase, an upstream pressure signal (59) biases the bypass valve toward a second position in which the auxiliary load circuit is blocked from communication with the reservoir, and can be pressurized and actuated.</p> |
