| 摘要 |
PURPOSE:To insure running safety without a fall of working efficiency and avoid overload condition of an engine by providing a vehicle speed reducing means to lower running speed of a vehicle body as the detected angular speed by an angular speed detecting means is larger. CONSTITUTION:At running of a vehicle body, oscillating angular speed of a front wheel accompanied with operation of a steering handle 21 is detected with an angular speed sensor A as an angular speed detecting means and the detected value is read, and if the value is larger than a setting value, speed change operation characteristic of a continuous variable transmission 6 against an operating quantity of a second shift lever 23 is controlled to change on the low speed side to operate an electric cylinder 18. Namely, a characteristic line in the small angular speed and nearly going straight condition is controlled to change to a characteristic line on the reducing speed side. In this way, accompanied with quick turning operation, speed is automatically reduced without troublesome operation. When turning is completed and an operation switch 27 is operated on a planting position, the belt type continuous variable transmission 6 is operated on the increasing speed side to return to a prescribed planting running speed. |
