Closed-loop hydraulic system having regeneration configuration
First Claim
1. A hydraulic system, comprising:
- an actuator;
a pump having variable displacement;
first and second passages connecting the pump to the actuator in a closed-loop manner;
a first load-holding valve disposed within the first passage and movable between a flow-blocking position and a flow-passing position;
a second load-holding valve disposed within the second passage and movable between a flow-blocking position and a flow-passing position;
a regeneration valve connected to the first passage at a location between the actuator and the first load-holding valve and to the second passage at a location between the actuator and the second load-holding valve, the regeneration valve being configured to selectively fluidly connect the first passage with the second passage;
a control valve configured to initiate simultaneous movements of the first and second load-holding valves; and
a controller in communication with the pump, the control valve, and the regeneration valve, wherein the controller is configured to;
cause the control valve to initiate simultaneous movement of the first and second load-holding valves toward their flow-blocking positions when a displacement of the pump is about zero;
selectively cause the regeneration valve to fluidly connect the first passage with the second passage when the displacement of the pump is non-zero; and
cause only one of the first and second load-holding valves to move to its flow-blocking position when the regeneration valve fluidly connects the first passage with the second passage.
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Accused Products
Abstract
A hydraulic system is disclosed that has first and second passages connecting a pump to an actuator in closed-loop manner, and first and second load-holding valves within the first and second passages. The hydraulic system may also have a regeneration valve connected to the first and second passages between the actuator and the first and second load-holding valves to selectively connect the first and second passages. The hydraulic system may further have a controller configured to cause a control valve to simultaneous move the first and second load-holding valves toward flow-blocking positions when pump displacement is about zero. The controller may also be configured to selectively cause the regeneration valve to connect the first and second passages when pump displacement is non-zero, and to cause only one of the first and second load-holding valves to move to its flow-blocking position when the regeneration valve connects the first and second passages.
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Citations
20 Claims
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1. A hydraulic system, comprising:
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an actuator; a pump having variable displacement; first and second passages connecting the pump to the actuator in a closed-loop manner; a first load-holding valve disposed within the first passage and movable between a flow-blocking position and a flow-passing position; a second load-holding valve disposed within the second passage and movable between a flow-blocking position and a flow-passing position; a regeneration valve connected to the first passage at a location between the actuator and the first load-holding valve and to the second passage at a location between the actuator and the second load-holding valve, the regeneration valve being configured to selectively fluidly connect the first passage with the second passage; a control valve configured to initiate simultaneous movements of the first and second load-holding valves; and a controller in communication with the pump, the control valve, and the regeneration valve, wherein the controller is configured to; cause the control valve to initiate simultaneous movement of the first and second load-holding valves toward their flow-blocking positions when a displacement of the pump is about zero; selectively cause the regeneration valve to fluidly connect the first passage with the second passage when the displacement of the pump is non-zero; and cause only one of the first and second load-holding valves to move to its flow-blocking position when the regeneration valve fluidly connects the first passage with the second passage. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15)
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16. A hydraulic system, comprising:
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an actuator; a pump having variable displacement; first and second passages connecting the pump to the actuator in a closed-loop manner; a first load-holding valve disposed within the first passage and movable between a flow-blocking position and a flow-passing position; a second load-holding valve disposed within the second passage and movable between a flow-blocking position and a flow-passing position; a regeneration valve connected to the first passage at a location between the actuator and the first load-holding valve and to the second passage at a location between the actuator and the second load-holding valve, the regeneration valve being configured to selectively fluidly connect the first passage with the second passage; a control valve configured to initiate simultaneous movements of the first and second load-holding valves; a charge circuit; at least one makeup valve fluidly connected between the charge circuit and the first and second passages, the at least one makeup valve being connected to the first and second passages at locations between the pump and the first and second load-holding valves; at least one relief valve fluidly connected between the charge circuit and the first and second passages, the at least one relief valve being connect to the first and second passages at locations between the actuator and the first and second load-holding valves; and a controller in communication with the pump, the control valve, and the regeneration valve, wherein the controller is configured to; cause the control valve to initiate simultaneous movement of the first and second load-holding valves toward their flow-blocking positions when a displacement of the pump is about zero; selectively cause the regeneration valve to fluidly connect the first passage with the second passage when the displacement of the pump is non-zero; and cause the regeneration valve to move only the first load-holding valve to its flow-blocking position when the regeneration valve fluidly connects the first passage with the second passage and when the pump supplies pressurized fluid through the second load-holding valve to the actuator, wherein the regeneration valve is movable from a first position at which fluid communication between the first and second passages is blocked and movement of the first and second load-holding valves is unaffected by the regeneration valve, and a second position at which the first passage is fluidly communicated with the second passage and one of the first and second load-holding valves is caused to move to its flow-blocking position by the regeneration valve.
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17. A method of operating a hydraulic system, comprising:
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pressurizing fluid with a pump; directing fluid from the pump through an actuator and back to the pump in a closed-loop manner via first and second passages; selectively simultaneously blocking the first and second passages with first and second load-holding valves to inhibit movement of the actuator when a displacement of the pump is about zero; selectively fluidly connecting the first passage with the second passage at locations between the actuator and the first and second load-holding valves via a regeneration valve when the displacement of the pump is non-zero; and selectively blocking only one of the first and second passages with the first or second load-holding valves when the first and second passages are fluidly communicated with each other via the regeneration valve. - View Dependent Claims (18, 19, 20)
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Specification