VENT FOR LOAD SENSE VALVES

摘要

A load sense passage in a load sense hydraulic system may be vented by allowing flow from the load sense passage to a reservoir via a drain passage when a first flow control valve is in a neutral position. This venting may be prevented by preventing flow from the load sense passage to a reservoir via the drain passage when the first flow control valve is in a flow-allowing position.

主权项

1. A load sense hydraulic system comprising:
a load sense passage communicating load sense pressure from a first hydraulic valve to a variable capacity hydraulic pump; a first load sense check valve disposed between the first hydraulic valve and the load sense passage and configured to allow flow from a flow portion of the first hydraulic valve to the load sense passage and block flow from the load sense passage to the flow portion of the first hydraulic valve; and the first hydraulic valve having a neutral position and a flow position, wherein in the neutral position, the first hydraulic valve closes the flow portion of the first hydraulic valve, preventing flow from a flow inlet of the first hydraulic valve towards a first work port of the first hydraulic valve, and opens a load sense portion, allowing flow from the load sense passage towards a drain passage, and wherein in the flow position, the hydraulic valve opens the flow portion of the first hydraulic valve, allowing flow from the flow inlet to the first work port of the first hydraulic valve, and closes the load sense portion, preventing flow from the load sense passage toward the drain passage.