| 摘要 |
PURPOSE: A lift control valve of a hydraulic system for a forklift is provided to prevent natural subsidence of a carriage and a mast assembly by selectively permitting counter flow of actuating fluid from the lower chamber of the lift cylinder with the check valve, to cut down expense by integrally embedding the flow regulating valve in the lift control valve, and to minimize flow resistance of actuating fluid and loss of power by supplying actuating fluid to the lift cylinder without passing the check valve. CONSTITUTION: A lift control valve comprises a valve block(110) having a bore(110a), an inflow passage(112) flowing actuating fluid, a flow passage(114) supplying actuating fluid from the bore to a lift cylinder or vice versa and having a first passage(114a) communicated with the bore and a second passage(114b) communicated with the lift cylinder, and a drain passage(116) draining actuating fluid from the lift cylinder; a spool having a first notch part(122) moving from the neutral position to the first position of the second position and communicating the inflow passage with the flow passage in the first position, and a communication passage(124) communicating the flow passage with the drain passage in the second position; a check valve(130) installed between the first passage and the second passage to supply actuating fluid from the bore to the lift cylinder and restrict counter flow of fluid to the bore; and a check valve control unit(140) regulating the check valve to return actuating fluid from the lift cylinder to the bore in the second position of the lift spool. |
