| 摘要 |
PURPOSE:To obtain the HST hydraulic traveling driving device, which selects the HST traveling automatically at the time of rearward traveling of a vehicle. CONSTITUTION:A bypass pipeline 14 is provided between main pipelines 3, 4 for connecting a hydraulic pump 2 and a hydraulic motor 5, and a switching valve 15 and a check valve 17 are provided on the way thereof. When a switching switch 24, which is coupled with a forward and rearward switching valve 8, is turned on with the switching of the switching valve 8 to the rearward position (R), the electrification from a power source 23 to a solenoid part of an electromagnetic control valve 19 is hindered by a relay 21, and the switching valve 15 is held in the (R) side to close the bypass pipeline 14. The check valve 17 is provided in the direction to be opened when the pressure of the main pipeline 4 exceeds the pressure of the main pipeline 3 to prevent the bypassing of the discharge oil from the main pipeline 3 to the main pipeline 4 when an acceleration pedal is depressed at the time of forward traveling of a vehicle. |
