Hydraulic system having variable back pressure control
First Claim
1. A hydraulic system for a machine having a linkage system, comprising:
- a tank configured to hold a supply of fluid;
at least one hydraulic actuator associated with the linkage system to affect movement of the linkage system, the at least one hydraulic actuator having a first pressure chamber and a second pressure chamber;
four independent metering valves associated with the at least one hydraulic actuator, with one of the independent metering valves associated with the first pressure chamber and having a valve element movable between a first position at which fluid communication between the first pressure chamber and the tank is blocked, and a second position at which fluid is allowed to drain from the first pressure chamber to the tank;
at least one sensor configured to sense a parameter indicative of a pressure in the second pressure chamber; and
a controller in communication with the one independent metering valve and the sensor, the controller configured to move the valve element of the one independent metering valve in response to the sensed parameter indicative of a pressure in the second pressure chamber toward a position to minimize voiding in the second pressure chamber.
3 Assignments
0 Petitions
Accused Products
Abstract
A hydraulic system for a work machine having a linkage system is disclosed. The hydraulic system has a tank configured to hold a supply of fluid and at least one hydraulic actuator associated with the linkage system to affect movement of the linkage system. The at least one hydraulic actuator has a first pressure chamber and a second pressure chamber. The hydraulic system also has an independent metering valve associated with the first pressure chamber. The independent metering valve has a valve element movable between a first position at which fluid communication between the first pressure chamber and the tank is blocked, and a second position at which fluid is allowed to drain from the first pressure chamber to the tank. The hydraulic system further has at least one sensor configured to sense a parameter indicative of a pressure in the second pressure chamber, and a controller in communication with the independent metering valve and the sensor. The controller is configured to move the valve element of the independent metering valve in response to the pressure.
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Citations
36 Claims
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1. A hydraulic system for a machine having a linkage system, comprising:
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a tank configured to hold a supply of fluid; at least one hydraulic actuator associated with the linkage system to affect movement of the linkage system, the at least one hydraulic actuator having a first pressure chamber and a second pressure chamber; four independent metering valves associated with the at least one hydraulic actuator, with one of the independent metering valves associated with the first pressure chamber and having a valve element movable between a first position at which fluid communication between the first pressure chamber and the tank is blocked, and a second position at which fluid is allowed to drain from the first pressure chamber to the tank; at least one sensor configured to sense a parameter indicative of a pressure in the second pressure chamber; and a controller in communication with the one independent metering valve and the sensor, the controller configured to move the valve element of the one independent metering valve in response to the sensed parameter indicative of a pressure in the second pressure chamber toward a position to minimize voiding in the second pressure chamber. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8)
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9. A hydraulic system for a machine having a linkage system, comprising:
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a tank configured to hold a supply of fluid; at least one hydraulic actuator associated with the linkage system to affect movement of the linkage system, the at least one hydraulic actuator having at least one pressure chamber; two independent metering valves associated with the at least one pressure chamber with one of the independent metering valves having a valve element movable between a first position at which fluid communication between the at least one pressure chamber and the tank is blocked, and a second position at which fluid is allowed to drain from the at least one pressure chamber to the tank; a sensor configured to sense at least one operating parameter of the linkage system and to generate a signal indicative of the at least one operating parameter; and a controller in communication with the one independent metering valve and the sensor, the controller configured to move the valve element of the one independent metering valve in response to the signal toward a position to minimize voiding in the at least one hydraulic actuator. - View Dependent Claims (10, 11, 12, 13, 14)
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15. A method of operating a hydraulic system associated with a linkage system, the hydraulic system including at least one hydraulic actuator having first and second pressure chambers and associated with the linkage system to affect movement of the linkage system, and four independent metering valves associated with the at least one hydraulic actuator, with one of the independent metering valves associated with the first pressure chamber and having a valve element movable between a first position at which fluid communication between the first pressure chamber and the tank is blocked, and a second position at which fluid is allowed to drain from the first pressure chamber to the tank, the method comprising:
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moving a valve element of the one independent metering valve between a first position and a second position to selectively block fluid from or drain fluid from the first pressure chamber of the at least one hydraulic actuator to the tank; sensing a parameter indicative of a pressure within the second pressure chamber of the at least one hydraulic actuator; and controlling movement of the valve element of the one independent metering valve between the first and second positions in response to the sensed parameter indicative of a pressure within the second pressure chamber toward a position to minimize voiding in the second pressure chamber. - View Dependent Claims (16, 17, 18, 19, 20, 21, 22)
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23. A method of operating a hydraulic system associated with a linkage system, the hydraulic system including at least one hydraulic actuator having at least one chamber and associated with the linkage system to affect movement of the linkage system, and two independent metering valves associated with the at least one chamber, with one of the independent metering valves having a valve element movable between a first position at which fluid communication between the at least one chamber and a tank is blocked, and a second position at which fluid is allowed to drain from the at least one chamber to the tank, the method comprising:
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moving the valve element of the one independent metering valve between a first position and a second position to selectively block fluid from or drain fluid from the at least one chamber of the at least one hydraulic actuator to the tank; sensing at least one operating parameter of the linkage system; generating a signal indicative of the at least one operating parameter; and controlling movement of the valve element of the one independent metering valve between the first and second positions in response to the signal to minimize voiding in the at least one hydraulic actuator. - View Dependent Claims (24, 25, 26, 27, 28)
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29. A machine comprising:
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a work tool; a linkage system operably connected to the work tool; and a hydraulic system configured to affect movement of the linkage system, the hydraulic system including; a tank configured to hold a supply of fluid; at least one hydraulic actuator associated with the linkage system to affect movement of the linkage system, the at least one hydraulic actuator having a first pressure chamber and a second pressure chamber; four independent metering valves associated with the at least one hydraulic actuator, with one of the independent metering valves associated with the first pressure chamber and having a valve element movable between a first position at which fluid communication between the first pressure chamber and the tank is blocked, and a second position at which fluid is allowed to drain from the first pressure chamber to the tank; at least one sensor configured to sense a parameter indicative of a pressure in the second pressure chamber; and a controller in communication with the one independent metering valve and the sensor, the controller configured to move the valve element of the one independent metering valve in response to the sensed parameter indicative of a pressure in the second pressure chamber toward a position to minimize voiding in the second pressure chamber. - View Dependent Claims (30, 31, 32, 33)
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34. A machine comprising:
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a work tool; a linkage system operably connected to the work tool; and a hydraulic system configured to affect movement of the linkage system, the hydraulic system including; a tank configured to hold a supply of fluid; at least one hydraulic actuator associated with the linkage system to affect movement of the linkage system, the at least one hydraulic actuator having at least one pressure chamber; two independent metering valves associated with the at least one pressure chamber with one of the independent metering valves having a valve element movable between a first position at which fluid communication between the at least one pressure chamber and the tank is blocked, and a second position at which fluid is allowed to drain from the at least one pressure chamber to the tank; a sensor configured to sense at least one operating parameter of the linkage system and to generate a signal indicative of the at least one operating parameter; and a controller in communication with the one independent metering valve and the sensor, the controller configured to move the valve element of the one independent metering valve in response to the signal toward a position to minimize voiding in the at least one hydraulic actuator. - View Dependent Claims (35, 36)
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Specification