Hydraulic system with load sense and methods thereof
AssigneeDanfoss Power Solution II Technology A/S
InventorsNilesh Anant Sutar, Muzammil Qayyumoddin Quazi
Life of this patent
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Abstract
A hydraulic system includes a pump in communication with a fluid reservoir and powered by a motor. A pressure compensator is adapted to adjust a position of a variable displacement mechanism of the pump. A load sensing line is adapted to communicate a highest load sensing pressure from a plurality of valves to the pressure compensator. The pressure compensator adjusts the variable displacement mechanism of the pump based on the highest load sensing pressure for maintaining a constant pressure drop across one or more work ports in each of the plurality of valves. The plurality of valves each include a load sense port having an integrated check valve that includes a metering orifice.
Claims17
A proportional load sensing hydraulic valve comprising:
- a housing having a bore and a major axis that extends through a center of the bore;
- a spool inside the bore of the housing and being coaxial with the major axis;
- a pump port, first and second work ports, a tank port, and a load sensing port, the load sensing port being coaxial with the major axis and the spool;
- and
- a check valve inside the load sensing port, the check valve having a metering orifice biased in a closed position by a check valve spring;
- wherein the metering orifice is adapted to balance a load sense pressure at the pump port with a pressure at the first and second work ports.
A hydraulic system comprising:
- a pump in communication with a fluid reservoir and powered by a motor, the pump including a variable displacement mechanism;
- a pressure compensator adapted to adjust the position of the variable displacement mechanism of the pump based on a load sense pressure;
- a load sense line adapted to communicate a highest load sense pressure from a plurality of valves to the pressure compensator;
- wherein each of the plurality of valves includes a spool positioned inside a bore of a housing, the housing defines a pump port, first and second work ports, a tank port, and a load sensing port, the load sensing port includes a check valve having a metering orifice biased in a closed position by a check valve spring, and the check valve is adapted to move from the closed position to a metered position when a minimum cracking pressure is reached;
- and
- wherein the metering orifice is adapted to balance a load sense pressure at the pump port with a pressure at the first and second work ports.
A method of operating a hydraulic system comprising:
- receiving a command to actuate an actuator of a mechanical device;
- sending a signal to a solenoid to move a control spool of a proportional hydraulic valve from a rested position to a first activated position;
- commanding a pump to direct fluid to the proportional valve through a pump port for feeding fluid to a work port and a load sensing port;
- receiving a load sense pressure from the load sensing port;
- and
- sending the load sense pressure to a pressure compensator adapted to modulate flow output from the pump for maintaining a constant pressure differential across the work port;
- wherein the load sensing port includes a check valve having a metering orifice biased in a closed position by a check valve spring, the metering orifice is adapted to move from the closed position to a metered position in response to sensing the load sense pressure;
- and
- wherein the metering orifice is adapted to balance a load sense pressure at the pump port with a pressure at the first and second work ports.
Dependencies are inferred from the claim text.