Independent supply and exhaust metering within a valve casting

摘要

The present disclosure provides a hydraulic system for controlling a load. The system includes a housing defining an inlet, a first port, and a second port. The system further includes a spool valve and a proportional control element. The spool valve is in fluid communication with the inlet and the second port and the proportional control element is in fluid communication with the first port. The proportional control element can be controllable to exhaust fluid from the first port to a reservoir. In this arrangement, the proportional control element and the spool valve are controlled independently of one another.

主权项

1. A hydraulic system including a reservoir, the hydraulic system for controlling a load, comprising:
a housing defining an inlet, a first port, a second port, and a tank galley coupled to the reservoir; a spool valve, including a spool configured to move within the housing, the spool being in fluid communication with the inlet, the first port, the second port, and the tank galley, wherein the spool is configured to meter fluid flow from the inlet to the first port and to meter fluid flow from the second port to the tank galley simultaneously due to the configuration of the spool; and a proportional control element, disposed in the housing and in fluid communication with the second port, wherein the proportional control element is configured to control the fluid flow from the second port, through the housing and past the spool, to the tank galley, and to the reservoir; wherein, the proportional control element and the spool valve are configured to be controlled independently of one another.