A hydrostatic drive system has a control unit which controls two back pressure valves to operate through a fluid cooling system or not.

摘要

Actuators (9a,9b) are operated by an engine (40) driven pump (41) and the pressure is released by back pressure valves (5,7) through a main lead (1) and through leads (4,6) according to a control valve (13), in which the fluid is cooled by a cooler (8), or directly by a temperature sensing system.