Smooth control of hydraulic actuator
AssigneeParker-Hannifin Corporation
InventorsRalf Gomm, Dale Vanderlaan
Life of this patent
Estimating the term…
Abstract
A method and system is provided for controlling a hydraulic actuator in a work machine by opening a load holding valve in a measured fashion in order to leak hydraulic pressure back into a depressurized portion of the hydraulic circuit, thereby minimizing or eliminating jerkiness in the actuator when the actuator is under an external load.
Claims23
A method for smoothly controlling a hydraulic actuator configured to actuate an implement that is acted upon by an external load in a first direction, the method comprising the steps of:
- receiving a command input to move the implement in the first direction;
- upon receipt of the command input, opening a load holding valve hydraulically connected between a pump and a side of the actuator upstream of the pump a first amount to create a leakage path, the first amount being less than fully open;
- equalizing pressure between the valve and the pump with pressure between the valve and the actuator via the leakage path;
- and
- after equalizing the pressure, fully opening the load holding valve.
9-11. (canceled)
A method for smoothly controlling a hydraulic actuator configured to actuate an implement that is acted upon by an external load in a first direction, the method comprising the steps of:
- receiving a command input to move the implement in the first direction;
- upon receipt of the command input, metering flow from the actuator via a load holding valve hydraulically connected between a pump and a side of the actuator upstream of the pump;
- equalizing pressure between the valve and the pump with pressure between the valve and the actuator via the metered flow;
- and
- after equalizing the pressure, metering flow from the actuator via the pump.
13-16. (canceled)
21-23. (canceled)
A hydraulic actuation system comprising:
- a hydraulic pump;
- a load holding check valve upstream of the pump;
- a controller configured to generate and send command signals to the load holding check valve;
- wherein the load holding check valve is configured to partially open upon receipt of an open command signal, and wherein the load holding check valve is configured to fully open in response to pump pressure exceeding a predetermined pressure.
Dependencies are inferred from the claim text.