Patent ID: 8701399
Filing Date: 2014-04-22
Classification: E02F,F15B,Y10T

Abstract:
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, 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.