| 摘要 |
PURPOSE:To improve control accuracy ever so better, by making a shift valve restrict the feed of a hydraulic medium to a first frictional engaging device till the lapse of time for selection from a second shift step to a first shift step reaches to a hour calculation time. CONSTITUTION:A timer 132 and a time calculating device 134 to calculate the fixed time related to the detected car speed of a car speed sensor 62 both are connected to a down shift detecting device 130 from the third speed to the second, while an underlap controlling solenoid valve 78 is controlled so as to restrict the feed of a hydraulic medium to a first frictional engaging device till the time measured by the said timer 132 reaches to a hour calculation time. With this constitution, in regard to control over an underlap period, influences of timing variations in time of transfer of controlling hydraulic pressure and variations in spring force of a control valve or the like are eliminable so that highly control accuracy is securable. |
