Variable delivery pump control system.

摘要

A variable delivery pump (10) has a pump control mechanism (12) in a housing secured thereto for governing directional flow of fluid through the pump, the pump being adapted to be connected through a closed loop (11) to a motor. A pressure compensating valve (14) is provided in the housing for governing pressure output of the pump, and a pump control cylinder (15) is provided for positioning a flow control cam (16) of the pump in accordance with flow of fluid through a direction control valve (13) and the pressure compensating valve (14). A cam plate (17) is coaxially connected to a directional control rotatable valve spool (20) of the direction control valve (13), the cam plate having an outer periphery that is continuously radially variable from a maximum radial point (17a) to a minimum radial point (17b, c) for either direction of rotation of the cam from the maximum radial point as the control spool is rotated in either direction from a normal position. The cam plate (17) actuates a cam follower (21), which in turn actuates a slideable sleeve (22) in the pressure compensating valve (14). A valve sleeve in the directional control valve is fixed against rotation. There is no feedback connection to the cam plate of the pump to either the direction control valve or the pressure compensating valve.