| 摘要 |
PURPOSE:To reduce an oil pressure loss by closing a solenoid valve for 1-2 shift control after completion of a shift from a second speed to a third speed, and closing a solenoid valve for 2-3 shift control after the solenoid valve is opened when a shift from a third speed to a second speed is effected. CONSTITUTION:Since a solenoid valve SL1 for 1-2 shift control is closed while a third speed is maintained, shut off is carried out between the control pressure port of a 1-2 shift valve 220 and a drain, whereby incurring of an oil pressure loss equivalent to the shut off is reduced. Since, during a shift from a third speed to a second speed, a 1-2 shift control valve SL1 is shifted from closing to opening before a solenoid valve SL2 for 2-3 shift control is shifted from opening to closing, a shift to a second speed is carried out in a state that a backup oil pressure is applied on the 1-2 shift valve 220 from a 2-3 shift valve 230, and shift characteristics between 2-3 is similar to characteristics here tofore provided. Since the solenoid valve SL1 for l-2 shift control is closed at a third speed as described above, an oil pressure loss between the control port of the 1-2 shift valve and a drain is eliminated and an oil pressure loss equivalent to elimination of the oil pressure loss is reduced. |
