| 摘要 |
PROBLEM TO BE SOLVED: To eliminate operation backlash of a work platform even when a vehicle is stored with the work platform positioned in a high position, and prevent malfunction of a delay in action occurring to an input from an operation device. SOLUTION: The hydraulic circuit of the vehicle for high lift work is provided with an ABT connection type swinging motor control valve 64 controlling swinging operation of the work platform by changing oil passages for hydraulic oil fed to a swinging motor 42 by a first hydraulic pump P1, an unloading valve 43 changing between feeding of the hydraulic oil from the first hydraulic pump P1 to a P port of the swinging motor control valve 64 and returning of the hydraulic oil to a reservoir T, and a check valve CV provided in a discharge oil passage L4 reaching the reservoir T from a confluence S of an oil passage L2 connected with a T port of the swinging motor control valve 64 and an oil passage L3 connected with a T port of the unloading valve 43 and allowing a flow of the hydraulic oil from a confluence S side to a reservoir T side and prohibiting a flow of the hydraulic oil from the reservoir T side to the confluence S side when a pressure of the hydraulic oil exceeds a preset cracking pressure. COPYRIGHT: (C)2003,JPO
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