Balancing unit for pressure fed hydrostatic transmission - has piloted relief valves augmenting input valve function

摘要

The balancing unit for hydro-static transmissions with pressurised motor to pump feeds has piloted relief piston valves augmenting the input valve function. The assembly has two relief valves with piloted piston valves, two ports into the pump to hydro- static motor feed, and a third port connecting with a high pressure source and the reservoir return feed. The ports (101, 101') are closed by cone nosed pistons (105) which slide in chambers (104, 104'). Fine bores (106, 106') traverse the pistons from chambers (104) to ports (101), cavity (103) links ports (101, 101') with the third port (103') and chambers (104) are closed by pilot valves (122, 122') locating in chambers (119, 119') which in turn contact to the fluid reservoir (R).