Meterless hydraulic system having load-holding bypass
First Claim
1. A load-holding valve, comprising:
- a valve block at least partially defining;
a pump passage;
an actuator passage;
a control passage;
a restricted passage connecting the actuator passage and the control passage; and
a bypass passage connecting the actuator passage and the control passage; and
a valve element disposed within the valve block and movable between a first position at which fluid flow between the pump passage and actuator passage is blocked, and a second position at which fluid is allowed to flow between the pump passage and the actuator passage.
1 Assignment
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Accused Products
Abstract
A hydraulic system is disclosed. The hydraulic system may have a pump, a hydraulic actuator, and first and second passages fluidly connecting the pump to the hydraulic actuator in a closed-loop. The hydraulic system may also have a control valve, and a load-holding valve configured to selectively lock movement of the hydraulic actuator. The load-holding valve may include a valve block at least partially defining a pump passage, an actuator passage, a control passage, a restricted passage connecting the actuator passage and the control passage, and a bypass passage connecting the actuator passage and the control passage. The load-holding valve may also include a valve element movable between a first position at which flow between the pump and the hydraulic actuator is blocked, and a second position at which fluid is allowed to flow between the pump and the hydraulic actuator, the valve element being spring-biased toward the first position.
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Citations
22 Claims
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1. A load-holding valve, comprising:
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a valve block at least partially defining; a pump passage; an actuator passage; a control passage; a restricted passage connecting the actuator passage and the control passage; and a bypass passage connecting the actuator passage and the control passage; and a valve element disposed within the valve block and movable between a first position at which fluid flow between the pump passage and actuator passage is blocked, and a second position at which fluid is allowed to flow between the pump passage and the actuator passage. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10)
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11. A hydraulic system, comprising:
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a pump; a hydraulic actuator; first and second passages fluidly connecting the pump to the hydraulic actuator in a closed-loop manner; a control valve; and a load-holding valve associated with at least one of the first and second passages and configured to selectively lock movement of the hydraulic actuator, the load-holding valve comprising; a valve block at least partially defining; a pump passage in fluid communication with the pump; an actuator passage in fluid communication with the hydraulic actuator via the one of the first and second passages; a control passage in fluid communication with the control valve; a restricted passage fluidly connecting the actuator passage and the control passage; a bypass passage connecting the actuator passage and the control passage; and a valve element disposed within the valve block and movable between a first position at which fluid flow between the pump and the hydraulic actuator is blocked, and a second position at which fluid is allowed to flow between the pump and the hydraulic actuator, wherein the valve element is spring-biased toward the first position. - View Dependent Claims (12, 13, 14, 15, 16, 17, 18, 19, 20, 21)
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22. A hydraulic system, comprising:
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a tank; a pump; a hydraulic actuator; first and second passages fluidly connecting the pump to the hydraulic actuator in a closed-loop manner; a control valve; an operator interface device; a controller in communication with the control valve and the operator interface device; and first and second load-holding valves associated with the first and second passages, respectively, and configured to selectively lock movement of the hydraulic actuator, each of the first and second load-holding valves comprising; a valve block at least partially defining; a pump passage in fluid communication with the pump; an actuator passage in fluid communication with the hydraulic actuator via the first or second passages; a control passage in fluid communication with the control valve; a restricted passage fluidly connecting the actuator passage and the control passage; and a bypass passage connecting the actuator passage and the control passage; a check element disposed within the bypass passage and configured to allow fluid to flow in one direction from only the control passage to the actuator passage; and a valve element disposed within the valve block and movable between a first position at which fluid flow between the pump and the hydraulic actuator is blocked, and a second position at which fluid is allowed to flow between the pump and the hydraulic actuator, wherein the valve element is spring-biased toward the first position, wherein; the controller is configured to selectively cause the control valve to move between a first position at which the control passage is fluidly communicated with the tank, and a second position at which the control passage is blocked from the tank based on input from the operator interface device; when the control passage is fluidly communicated with the tank, the valve element of each of the first and second load-holding valves is allowed to move to the second position; and when the control passage is blocked from the tank, the valve element of each of the first and second load-holding valves is urged toward the second position.
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Specification