Speed control for hydraulic motor - operates using pressure from two hydraulic valves acting on friction plate

摘要

A motor (13) fed with pressure medium by a pump (10) has two intermeshing gear wheels against the lateral faces of which lies a friction plate (26) having minimal axial movement. The plate (26) is acted upon by two pressure fields. The first area is under constant high pressure while the second area is subject to a controlled pressure after start-up. The pressure acting on the second area is controlled by two valves (21,15). The first valve (21), located in a bypass line, is activated by the pressure from a throttle valve (15) opposing the force of a spring (23). The throttle valve (15), located in the return line (14) is operated by pressure in the return line (14) opposing the force of a spring (17). USE/ADVANTAGE - No non-hydraulic controls are needed thus keeping the cost down.