| 摘要 |
PROBLEM TO BE SOLVED: To control a speed change condition so as to correspond to a gradient and a curve in a traveling road, and to realize a stable drive condition, relating to an automatic transmission suited for use in a mechanical automatic transmission provided in a large sized automobile of truck, bus, or the like. SOLUTION: An automatic transmission has a gradient detection means 52 detecting a gradient of a road in the front at traveling time of a vehicle and a climbing time shift-down decision means 57 deciding necessity of a shift- down of a speed change shift for traveling of the vehicle at the present running car speed in the front road based on its gradient detected by the gradient detection means 52, and in this constitution, when the shift down is decided necessary by the climbing time shift down decision means 57, prior to climbing of the front road, the shift down of the speed change shift is performed. |
