Control of a fluid pump assembly

A pump control assembly comprising:

• a fluid pump assembly including:
• a fluid pump having a fluid inlet and a fluid outlet, the fluid pump including a variable displacement mechanism;
• a load sensing valve adapted to adjust the position of the variable displacement mechanism, the load sensing valve having a first end and an oppositely disposed second end;
• an actuator in fluid communication with the fluid pump assembly;
• a position sensor for monitoring the position of the actuator;
• a ramping valve providing selective fluid communication between the fluid outlet of the fluid pump and the first end of the load sensing valve to adjust the variable displacement mechanism;
• and
• an electronic control unit in electrical communication with the position sensor and the ramping valve, wherein the electronic control unit transmits an output current to the ramping valve in response to the position of the actuator;
• and
• an orifice providing fluid communication between the first end of the load sensing valve and a fluid reservoir.

A pump control assembly comprising:

• a fluid pump assembly including:
• a fluid pump having a fluid inlet and a fluid outlet, the fluid pump including a variable displacement mechanism that is movable between a neutral position and a first position;
• a load sensing valve adapted to adjust the position of variable displacement mechanism, the load sensing valve having a first end and an oppositely disposed second end;
• an actuator in fluid communication with the fluid pump assembly, the actuator including:
• a housing having a first axial end and an oppositely disposed second axial end, the housing defining a bore;
• a piston disposed in the bore of the housing;
• and
• a ramping valve assembly including a ramping valve that is in fluid communication with the fluid outlet of the fluid pump;
• an electronic control unit configured to electronically actuate the ramping valve to provide fluid communication between the fluid outlet of the fluid pump and the first end of the load sensing valve when the piston of the actuator approaches one of the first and second axial ends so that the variable displacement mechanism is moved toward the neutral position.

A pump control assembly comprising:

• a fluid pump assembly including:
• a fluid pump having a fluid inlet and a fluid outlet, the fluid pump including a variable displacement mechanism that is movable between a neutral position and a first position;
• a load sensing valve adapted to adjust the position of variable displacement mechanism, the load sensing valve having a first end and an oppositely disposed second end;
• an actuator in fluid communication with the fluid pump assembly, the actuator including:
• a housing having a first axial end and an oppositely disposed second axial end, the housing defining a bore;
• a piston disposed in the bore of the housing;
• and
• a ramping valve assembly including a ramping valve that is in fluid communication with the fluid outlet of the fluid pump, wherein the ramping valve is electronically actuated to provide fluid communication between the fluid outlet of the fluid pump and the first end of the load sensing valve when the piston of the actuator approaches one of the first and second axial ends so that the variable displacement mechanism is moved toward the neutral position, the ramping valve assembly including an orifice that provides fluid communication between the first end of the load sensing valve and a fluid reservoir.

A method for actuating a pump control assembly comprising:

• providing a pump control assembly including:
• a fluid pump having a fluid inlet and a fluid outlet, the fluid pump including a variable displacement mechanism;
• a load sensing valve adapted to adjust the position of the variable displacement mechanism, the load sensing valve having a first end and an oppositely disposed second end;
• an actuator in fluid communication with the fluid outlet of the fluid pump;
• and
• a ramping valve providing selective fluid communication between the fluid outlet and the first end of the load sensing valve;
• receiving a signal from a position sensor, wherein the position sensor is adapted to monitor the position of the actuator;
• transmitting an output current signal to the ramping valve when the actuator approaches a travel limit of the actuator so that the variable displacement mechanism is displaced toward a neutral position, wherein a profile of the output current signal includes a ramp-down portion that has a decreasing magnitude over a predetermined time interval.