LIFT CYLINDER HYDRAULIC CIRCUIT OF TRACTOR

摘要

PROBLEM TO BE SOLVED: To prevent an oil temperature rise and reduce horse power loss in the hydraulic circuit of a lift cylinder of a single acting type for lifting a working machine or the like. SOLUTION: In this lift cylinder hydraulic circuit of a tractor, a pilot check valve 5 is provided in a cylinder circuit 4 between the lift cylinder 1 of the single acting type and a lift control valve 3 operated by a proportional solenoid 2, and a pilot circuit 6 is provided for releasing a pilot pressure after the pilot check valve 5 is opened by the pilot pressure during lowing operation of the lift control valve 3.