| 摘要 |
PROBLEM TO BE SOLVED: To prevent a response delay of control and prevent a shift shock and extension of a time interval at down shift time, by simple control. SOLUTION: An automatic transmission, in a speed change mechanism thereof, has a rotary member reversing the direction between a rotational direction at high speed stage time and an action direction of reaction force torque at low speed stage time, and a band brake 32 operated by a hydraulic servo 4 capable of impeding rotation due to reaction force torque at this low speed stage time by self energy action. A control device 6 has a synchronous decision means S36 for a low speed stage, a standby hydraulic pressure, lower than an engageable hydraulic pressure at self energy action time by a prescribed amount to be boosted up by a boost amount of reference after passing the synchronous point, is supplied to the hydraulic servo 4 of the band brake 32 at down shift time by a fixed pressure holding means S34 till materialization of synchronous decision, and after synchronous decision, the hydraulic pressure is increased to the engageable oil pressure by a booster means S39, and the rotary member is slowly locked while preventing extension of a time interval. |
