| 摘要 |
<P>PROBLEM TO BE SOLVED: To prevent cavitation of a hydraulic motor with a simple constitution. Ž<P>SOLUTION: This cooling fan driving circuit has a hydraulic pump 1 driven by an engine 10, the hydraulic motor 3 driving a cooling fan 13 for blowing cooling air to heat exchangers 11 and 12, a directional control valve 21 controlling the flowing direction of pressure oil to the hydraulic motor 3 from the hydraulic pump 1, a pair of main pipes L1 and L2 connecting the directional control valve 21 and the hydraulic motor 3, a pair of check valves 22A and 22B arranged between the pair of main pipes, replenishing circuits L21-L23 introducing return oil passing through the directional control valve 21 to the suction side main pipe of the hydraulic motor via the check valves 22A and 22B when rotating the hydraulic motor 3 by inertia force of the cooling fan 13, and a valve device 23 increasing pressure of the replenishing circuits L21-L23 when rotating the hydraulic motor 3. The directional control valve 21, the check valves 22A and 22B and the valve device 23 are arranged in an integral block 20. Ž<P>COPYRIGHT: (C)2010,JPO&INPIT Ž
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