| 摘要 |
A system for controlling fluid flow from a source to a steering motor and one or more auxiliary motors comprises a priority valve and a steering controller. The priority valve has a housing that includes an inlet port connected to the source, a priority flow outlet port, an auxiliary flow outlet port, and a pilot port. A biasing spring urges the priority valve spool toward a priority position directing all flow from the inlet port to the priority port. The priority valve includes a pilot flow conduit directing a pilot flow of fluid through an orifice to the pilot port. Pressure upstream of the pilot flow orifice acts on the priority valve spool in opposition to the spring, and pressure downstream of the pilot flow orifice acts on the valve spool in addition to the spring. The steering controller has a load sense cavity communicating with a load sense port, and a neutral vent orifice which, when the steering controller is in neutral, communicates said load sense cavity with a return port for allowing a pilot flow of fluid from the pilot port of the priority valve to flow through said steering controller to the reservoir. Upon activation from its neutral position, the steering controller substantially restricts flow through the neutral vent orifice to the reservoir before its main flow control orifice opens.
|
