Patent ID: 11906986
Assignee: PARKER HANNIFIN EMEA S.À.R.L.
Field: Mechanical elements (Mechanical engineering)
Classification: CPC F  G | IPC F  G

Claim 17:
18. A method for controlling a pressure level of a hydraulic fluid in a return line from a hydraulic actuator arrangement using a counter pressure valve arrangement, the method comprising:
providing a counter pressure valve having a moveable valve member, a counter pressure regulating port, a tank port and a pump port,
connecting the counter pressure regulating port to the hydraulic actuator arrangement via the return line, connecting the tank port to a tank having low pressure hydraulic fluid, and connecting the pump port to a source of pressurised hydraulic fluid,
supplying pressurised hydraulic fluid to the return line by setting the valve member in the first position [active refill position], thereby effecting fluid communication between the pump port and the counter pressure regulating port, and
discharging hydraulic fluid from the return line to the tank by setting the valve member in a second position [pressure relief position], thereby effecting fluid communication between the counter pressure regulating port and the tank port,
wherein the counter pressure valve further includes an electrohydraulic pilot valve that provides a variable pilot pressure acting on a first axial end of the valve member of the counter pressure valve, and
wherein the electrohydraulic pilot valve has an input port configured to be fluidly connected to a pressure source, an output port configured to be connected to a pilot pressure port of the first axial end of the valve member of the counter pressure valve via a pilot pressure line, and a discharge port configured to be connected to the tank having the low pressure hydraulic fluid.