| 摘要 |
PROBLEM TO BE SOLVED: To switch a tractor to a proper traveling form for a change of a working state by constituting the tractor to switch a two-wheel drive traveling on a hard traveling surface and four-wheel drive traveling on a soft traveling surface, to perform driving by increasing peripheral speed of a front wheel more than peripheral speed of a rear wheel when turning travel and to brake the rear wheel on the turning an inside. SOLUTION: When 'a four-wheel drive mode' is selected by a driving mode switch, a front-wheel drive clutch 19 and left and right front wheel clutches 25 are in connected states, power from a transmission 12 is transmitted to a rear axle 2 via a rear wheel differential device 15 and power is transmitted to a front wheel 1 via the front-wheel drive clutch 19 and a front wheel differential device 21. When 'a two-wheel drive mode' is selected, the front-wheel drive clutch 19 and the left and right front wheel clutches 25 are disconnected. When 'a turning mode' is selected, the front wheel 1 is made a state that the front wheel 1 is driven at substantially the same speed as peripheral speed of the rear wheel 2 in a straight advancing and is switched to a state that the front wheel 1 is driven by increasing peripheral speed more than peripheral speed of the rear wheel 2 in turning and the rear wheel 2 on the turning inside is switched to a state that the rear wheel 2 is braked. |
