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1. WO2011071578 - CONTROL SYSTEM FOR SWASHPLATE PUMP

Note: Text based on automatic Optical Character Recognition processes. Please use the PDF version for legal matters

[ EN ]

Claims

1. A control system for a pump (10), comprising:

a tiltable swashplate (28);

at least one actuator (34) movable to tilt the swashplate;

a supply of pressurized fluid (42);

a drain (52);

a first circuit (48) 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 (50) 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 (58) configured to connect the first circuit to at least one of the supply and the drain during a normal operating condition and to connect the second circuit to the supply and to the drain during a failsafe condition.

2. The control system of claim 1, further including at least one electrically powered valve (60) 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 (34) located to act on a first

portion of the swashplate relative to a tilt axis (30) of the swashplate;

the at least one electrically powered valve is a first electrically powered

valve (60) associated with control of the first actuator; and

the control system further includes:

a second actuator (36) 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 (62) associated with control of

the second actuator.

4. The control system of claim 3, further including a third valve (72) 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

(74) connecting an edge of the swashplate to the third valve.

8. The control system of claim 7, further including a first sensor (31) 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, wherein the failsafe condition is associated with an electrical power malfunction.

10. A method of controlling a swashplate pump (10), comprising:

displacing a main flow of fluid from the swashplate pump;

selectively directing a pilot flow of fluid to and from an actuator (34) of the swashplate pump via a first path (48) 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 (50) to shift the swashplate pump towards a non-displacement position during a second condition.