| 摘要 |
When an hydraulic motor 1 is adjusted from a low speed mode to a high speed mode by pilot pressure 9, the maximum pressure of a drive circuit for the hydraulic motor is changed. As shown, the pilot pressure 9 also acts on a valve 13 so that a relief valve 5 becomes effective instead of a relief valve 14 set at a lower value. The control circuit prevents insufficiency of the running torque in high speed running on flat road and excessiveness of the running torque in low speed running on soft road. <IMAGE> |
