Hydraulic system for working machine
First Claim
1. A hydraulic system for a working machine, the hydraulic system comprising left and right track devices configured to be driven by separate track drive motors, a dozer device configured to be driven by a dozer cylinder, track control valves provided respectively for the left and right track devices, and for respectively controlling the track drive motors, auxiliary control valves for controlling, apart from the track drive motors and the dozer cylinder, hydraulic actuators, and two independent hydraulic-fluid discharge ports, the hydraulic system comprising:
- a pair of dozer control valves configured to be concurrently operable for controlling the dozer cylinder;
a pilot pressure valve configured to be switchable between an independent position and a merging position,the independent position being a position that allows, when the left and right track devices are operated while the auxiliary control valves are not operated, hydraulic fluid from one of the hydraulic-fluid discharge ports to be independently supplied to one of the track control valves and to one of the dozer control valves, and hydraulic fluid from the other of the hydraulic-fluid discharge ports to be independently supplied to the other of the track control valves and to the other of the dozer control valves,the merging position being a position that allows, when at least one of the auxiliary control valves is operated, the hydraulic fluid from the one of the hydraulic-fluid discharge ports and the hydraulic fluid from the other of the hydraulic-fluid discharge ports to be merged and then supplied to the at least one of the auxiliary control valves that has been operated, and to the track control valves and the dozer control valves; and
pressure compensation valves provided respectively in the control valves, and configured to distribute hydraulic fluid to the respective control valves at flow rates in accordance with extent of actuation of, irrespective of the magnitude of loads acting on, the hydraulic actuators.
1 Assignment
0 Petitions
Accused Products
Abstract
A pair of dozer control valves V3, V6 concurrently operable; a pilot pressure valve V14 switchable between an independent position 27 where, when only track devices 5 are operated, discharged fluid from one hydraulic-fluid discharge port P1 is independently supplied to one track control valve and one dozer control valve, and discharged fluid from the other hydraulic-fluid discharge port P2 is independently supplied to the other track control valve and the other dozer control valve, and a merging position 28 where, when the other control valves are operated, discharged fluid from the one hydraulic-fluid discharge port and from the other hydraulic-fluid discharge port are merged and supplied to the control valves V1 to 10; and pressure compensation valves V11 in the control valves and for distributing hydraulic fluid at flow rates based on extent of actuation of the other control valves operated, irrespective of the magnitude of the loads.
18 Citations
6 Claims
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1. A hydraulic system for a working machine, the hydraulic system comprising left and right track devices configured to be driven by separate track drive motors, a dozer device configured to be driven by a dozer cylinder, track control valves provided respectively for the left and right track devices, and for respectively controlling the track drive motors, auxiliary control valves for controlling, apart from the track drive motors and the dozer cylinder, hydraulic actuators, and two independent hydraulic-fluid discharge ports, the hydraulic system comprising:
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a pair of dozer control valves configured to be concurrently operable for controlling the dozer cylinder; a pilot pressure valve configured to be switchable between an independent position and a merging position, the independent position being a position that allows, when the left and right track devices are operated while the auxiliary control valves are not operated, hydraulic fluid from one of the hydraulic-fluid discharge ports to be independently supplied to one of the track control valves and to one of the dozer control valves, and hydraulic fluid from the other of the hydraulic-fluid discharge ports to be independently supplied to the other of the track control valves and to the other of the dozer control valves, the merging position being a position that allows, when at least one of the auxiliary control valves is operated, the hydraulic fluid from the one of the hydraulic-fluid discharge ports and the hydraulic fluid from the other of the hydraulic-fluid discharge ports to be merged and then supplied to the at least one of the auxiliary control valves that has been operated, and to the track control valves and the dozer control valves; and pressure compensation valves provided respectively in the control valves, and configured to distribute hydraulic fluid to the respective control valves at flow rates in accordance with extent of actuation of, irrespective of the magnitude of loads acting on, the hydraulic actuators. - View Dependent Claims (2, 3, 4, 5, 6)
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Specification