Hydraulic medium supply device for servo steering - has variable displacement pump for normal supply, and smaller volume constant pump

摘要

The device is for supply of pressure medium to a priority primary load circuit, and at least one auxiliary load circuit, e.g. servo steering in a motor vehicle. It has a first and a second fluid source, and associated priority valves. The first fluid source is formed by a variable displacement pump (16), which has a larger volume the constant pump (17), forming the second source. The control pressure connection (19) of this is charged by a second load pressure signal (43), and additionally by a first signal (36, 42) from the primary circuit (11). The second pirority valves (45) are regulated dependant upon the differential load pressure signal, which regulates the flow volume requirements in the primary circuit. The active pressure differential (32), to control the fist priority valves (23), is larger than the pressure differential (55) to control the second priority valves. USE - Hydraulic power supply for vehicle servo steering.