| 摘要 |
PURPOSE:To enable a vehicle to easily extricate from muddy places having various dampnesses, by providing a control means for controlling the braking force of a control means in accordance with a dampness signal from a dampness sensor. CONSTITUTION:A dampness sensor 61 detects the dampness condition of a road surface and delivers a dampness signal S. Further, a control means 62 stop a motor 49 when a hydraulic pressure indicated by a hydraulic pressure signal P exceeds a predetermined pressure, but rotates the same when the hydraulic pressure P is below the predetermined pressure. If the dampness of a muddy place is high, the current value of the signal S becomes high to increase a reference voltage V, and therefore, the control voltage becomes high. Accordingly the total time during which a two-position selector valve 55 takes its second position 59 is made to belong, and therefore, the amount of oil discharged from a main passage 52 into a reservoir 50 through the first position 58 becomes less. Therefore, the pressure in the main passage 52, a hydraulic pressure port 43 and a cylinder chamber 43 becomes high so that the external force F is increased to make the control force muF greater. |
