| 摘要 |
PROBLEM TO BE SOLVED: To provide a hydraulic driven vehicle having a means for automatically preventing engine overrun caused in descending a steep slope. SOLUTION: When the rotating speed of an engine 18 exceeds a predetermined rotating speed, the delivery of a fixed displacement pump 16 is increased so that the pressure of a pilot pressure circuit 49 increases. The increased oil pressure is applied to motor displacement selector valves 33, 34 to be switched, whereby passing oil quantity per one revolution of hydraulic motors 19, 21 is shifted from a small displacement position to a large displacement position.
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