| 摘要 |
PROBLEM TO BE SOLVED: To provide a running driving device having a good acceleration property which carries out the change over operation from the advance to the retreat or from the retreat to the advance, in a hydraulic driving type working vehicle, and its control method. SOLUTION: In the running driving device of a hydraulic driving type working vehicle which has a hydraulic pump 2 for running driven by the motive power of an engine 1; a hydraulic motor 6 to run the vehicle by receiving a discharge oil from the hydraulic pump 2 for running; and a change over valve 5 for running to exhaust the return oil from the hydraulic motor 6 to a tank 9, as well as to receive the discharge oil from the hydraulic motor 2 and to feed it to the hydraulic motor 6; a relief valve to govern the pressure to brake the hydraulic motor 6 when the speed of the vehicle is reduced; and a pressurizing means 105 to raise the pressure of the relief valve to brake the hydraulic motor 6, when the rotation frequency of the engine 1 is increased during the change over time from the advance to the retreat, or from the retreat to the advance; are also provided. |
