| 摘要 |
PURPOSE:To relieve impact of switching operation of a front wheel speed change gear at the time of turning a working truck, by disconnecting transmission of power to a front wheel when a steering wheel for the front wheel is operated by a first setting angle or more and less than a second setting angle, and operating the front wheel power transmission to the speed increase side when the steering wheel is operated over the second setting angle. CONSTITUTION:During the time when a steering wheel 20 for front wheel is operated by a first setting angle theta1 or more and less than a second setting angle theta2, power transmission to a front wheel 1 is disconnected, and when the steering wheel 20 is operated over the second setting angle theta2, a front wheel speed change gear 10 is operated to the speed increase side. In such arrangement, two-wheel drive condition of rear wheel appears immediately before the front wheel speed change gear 10 is switched to speed increase condition so as to relieve droppage of speed at the start of turning during two-wheel drive condition. When the front wheel 1 is brought into speed increase condition subsequently, the impact is reduced because the difference from previous driving speed is lower than conventional one. Consequently, switching impact of the front wheel speed change gear 10 can be relieved when a working truck is turned.
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