| 摘要 |
PURPOSE:To prevent the nonconformity of a frictional clutch element being unexpectedly engaged during a shift by providing delay means for delaying the release of hydraulic pressure from a release chamber with respect to the release of hydraulic pressure from an apply chamber during a shift in which hydraulic pressure is released from both the apply chamber and the release chamber of the frictional clutch element. CONSTITUTION:A 2-4 brake 26 having an apply chamber S/A and a release chamber S/R is provided and a 1-2 shift valve 33 and a 3-4 shift valve 35 are controlled so that hydraulic pressure is supplied to and released from oil passages 71, 81 leading to an apply port 26a and a release port 26b, respectively, and application and releasing of the 2-4 brake are switched by control of the supply and release of hydraulic pressure to and from both of the chambers S/A, S/R, so as to shift gears. In such an automatic transmission, the release of hydraulic pressure from the release chamber S/R is delayed by a delay timer Tm with respect to the release of hydraulic pressure from the apply chamber S/A when each of the shift valves 33, 35, etc., is controlled by a control unit 32, so as to prevent the timing of the release of hydraulic pressure from the apply chamber S/A from being delayed as compared to that from the release chamber S/R. |
