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1. US20110138799 - Control system for swashplate pump

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[ EN ]

Claims

1. A control system for a pump, comprising:
a tiltable swashplate;
at least one actuator movable to tilt the swashplate;
a supply of pressurized fluid;
a drain;
a first circuit connectable to the supply of pressurized fluid and to the drain, and configured to control operation of the at least one actuator;
a second circuit connectable to the supply of pressurized fluid and to the drain and configured to control operation of the at least one actuator; and
a failsafe valve configured to connect the first circuit to at least one of the supply and the drain only during a normal operating condition and to connect the second circuit to the supply and to the drain only during a failsafe condition,
wherein the second circuit is further configured to shift the swashplate towards a non-displacement position during the failsafe condition.
2. The control system of claim 1, further including at least one electrically powered valve disposed within the first circuit and configured to regulate fluid flow between the first circuit and the at least one actuator.
3. The control system of claim 2, wherein:
the at least one actuator is a first actuator located to act on a first portion of the swashplate relative to a tilt axis of the swashplate;
the at least one electrically powered valve is a first electrically powered valve associated with control of the first actuator;
and the control system further includes:
a second actuator located to act on an opposing second portion of the swashplate relative to the tilt axis and the first portion of the swashplate; and
a second electrically powered valve associated with control of the second actuator.
4. The control system of claim 3, further including a third valve mechanically connected to the swashplate and disposed within the second circuit, the third valve movable between a first position at which the first actuator is provided with pressurized fluid and the second actuator is drained of pressurized fluid, a second position at which fluid communication with both the first and second fluid actuators is blocked, and a third position at which the second actuator is provided with pressurized fluid and the first actuator is drained of pressurized fluid.
5. The control system of claim 4, wherein the failsafe valve is a two position, six-way valve connected to the supply of pressurized fluid, the drain, the first and second electrically powered valves via a branching supply passage, the first and second electrically powered valves via a branching drain passage, and at two locations to the third valve.
6. The control system of claim 4, wherein the failsafe valve is a two position, seven-way valve connected to the supply of pressurized fluid, at two locations to the drain, to the first electrically powered valve, to the second electrically powered valve, and at two locations to the third valve.
7. The control system of claim 4, further including a link mechanically connecting the swashplate to the third valve.
8. The control system of claim 7, further including a first sensor disposed proximal the swashplate to detect a position of the swashplate and responsively generate a signal indicative of a tilt angle of the swashplate.
9. The control system of claim 1, further including at least one sensor configured to detect an output of the pump, wherein the failsafe condition is associated with a malfunction of the at least one sensor.
10. The control system of claim 1, wherein the fails condition is associated with an electrical power malfunction.
11. The control system of claim 1, wherein the supply of pressurized fluid is received from offboard the pump.
12. A control system for a pump, comprising:
a tiltable swashplate;
at least one actuator movable to tilt the swashplate;
a supply of pressurized fluid;
a drain;
at least a first electrically powered valve configured to selectively connect the supply and the drain to the at least one actuator to move the at least one actuator to a desired position;
a second valve mechanically connected to the swashplate and configured to selectively connect the supply and the drain to the at least one actuator to move the tiltable swashplate toward a neutral position; and
a third electrically powered valve being energized to connect the at least a first electrically powered valve to the supply and the drain during a first condition, and spring-biased to connect the second valve to the supply and the drain during a second condition.
13. The control system of claim 12, wherein:
the at least one actuator is a first actuator located to act on a first portion of the swashplate relative to a tilt axis of the swashplate;
the at least a first electrically powered valve is a first electrically powered valve associated with control of the first actuator; and
the control system further includes:
a second actuator located to act on an opposing second portion of the swashplate relative to the tilt axis; and
a second electrically powered valve associated with control of the second actuator.
14. The control system of claim 13, wherein the second valve is movable between a first position at which the first actuator is provided with pressurized fluid and the second actuator is drained of pressurized fluid, a second position at which fluid communication with the first and second fluid actuators is blocked, and a third position at which the second actuator is provided with pressurized fluid and the first actuator is drained of pressurized fluid.
15. The control system of claim 13, wherein the third electrically powered valve is a two position, six-way valve connected to the supply of pressurized fluid, the drain, the first and second electrically powered valves via a branching supply passage, the first and second electrically powered valves via a branching drain passage, and at two locations to the third valve.
16. The control system of claim 13, wherein the third electrically powered valve is a two position, seven-way valve connected to the supply of pressurized fluid, at two locations to the drain, to the first electrically powered valve, to the second electrically powered valve, and at two locations to the third valve.
17. A method of controlling a swashplate pump, comprising:
displacing a main flow of fluid from the swashplate pump;
selectively directing a pilot flow of fluid to and from an actuator of the swashplate pump via a first path to adjust a displacement of the swashplate pump during a first operating condition; and
overriding control of the actuator via the first path by controlling flow to and from the actuator via a second path to shift the swashplate pump towards a non-displacement position during a second condition.
18. The method of claim 17, wherein the second condition is associated with a system malfunction.
19. The method of claim 17, further including sensing a pressure of the displaced fluid and responsively generating a pressure signal, wherein the second condition is associated with a value of the pressure signal.
20. The method of claim 17, further including detecting an angle of a driving surface of the swashplate pump, and responsively generating a signal indicative of a rate of the displacing.