Patent ID: 7013746

Claim:
A control method for an automatic transmission having an input shaft rotating by torque from a drive power source, an output shaft for outputting a rotation torque to a drive shaft of a vehicle, plural idle gears for transferring the rotation torque between said input shaft and output shaft, and plural synchromeshes that constitute respective gear positions by engaging with each idle gear, furthermore said synchromeshes are equipped with; plural hubs rotating integrally with said input shaft or said output shaft; plural sleeves respectively provided on said hubs, rotatable integrally with said hubs and movable axially on said hubs; and plural rings respectively provided between said hubs and idle gears, and moving any of said sleeves toward the corresponding idle gear, any of said rings is pressed on the idle gear, the rotation torque from said input shaft is transferred to said output shaft through the ring and idle gear by the friction, and the sleeve can move to engage into the idle gear with synchronized speed, wherein the control of said automatic transmission comprising: when shifting the gear position into a target gear position from a current gear position, using some gear position different from said current gear position as one distributing gear position, so that controlling the pressing load of a synchromesh of said one distributing gear position to transfer at least part of the rotation torque from the drive power source by the friction, thereby releasing at least part of the rotation torque transferred by a synchromesh of said current gear position; moving the synchromesh of said current gear position to a disengaging position not meshed with said idle gear; thereafter using another gear position different from said target gear position and said one distributing gear position as another distributing gear position, so that controlling the pressing load of the synchromesh of said another distributing gear to increases gradually the transfer torque by the friction, and simultaneously decreasing gradually the pressing load of the synchromesh of said one distributing gear position; besides such a distribution of transfer torque, synchronizing the speed of said input shaft with the speed corresponding to said target gear position by controlling the speed of said input shaft, and then moving the synchromesh of the target gear position to the meshing position.