To perform slow-speed traveling control to a work vehicle in a state of large work ability wherein an engine speed is increased.
The work vehicle has a charging pump 5, a working hydraulic pump 4 and a traveling hydraulic pump 3 driven by an engine 2; a hydraulic motor 6 for driving a traveling device, closed-circuit-connected to the traveling hydraulic pump 2; and a pilot valve 8 controlling a discharge oil amount of the traveling hydraulic pump 3. In the work vehicle, an orifice 15 generating differential pressure according to a flow rate is provided halfway along a control circuit 14 connected to the pilot valve 8 from the charging pump 5, pilot conduits 16, 17 are connected to the pilot valve 8 from the primary side and the secondary side of the orifice 15, the secondary side of the orifice 15 is connected to a low-pressure leaf valve 19, and the primary side of the orifice 15 is connected to the suction side of the charging pump 5 through a needle valve 21 whose opening can be finely adjusted.
MORITA SHIGERU
JPH11257489A | 1999-09-21 | |||
JPH0650955U | 1994-07-12 | |||
JPS5345391U | 1978-04-18 | |||
JPH051768A | 1993-01-08 |
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