Hydraulic multiway motor control valve independent of load - has load-pressure passage controllable by pressure-compensation valve slide

摘要

The hydraulic valve controls a hydraulic motor independently of load, having a pressure-compensation valve upstream of the control valve slide. The compensation valve slide is adjusted dependent on pressure, being subjected to upstream pressure in opposition to its spring, and to downstream pressure in the opposite direction. This keeps the pressure drop across the first throttling positions at the control slide constant independent of the value of a positive load on the motor. Second throttles at the control slide pass the fluid from the motor to the tank. Downstream of the control slide and in the return pipe to the tank is a second pressure-compensation valve, subjected to the pressures upstream and downstream of the second throttles in opposition to a spring, keeping the pressure drop across the second throttles constant under a negative load on the motor. A load pressure passage feeds the pressure in the motor chamber connected to the inlet back to a control pressure union. The load pressure passage (64) is controllable by the slide (17) of the second pressure-compensation valve.