AUTOMATIC TRANSMISSION DEVICE FOR VEHICLE

PROBLEM TO BE SOLVED: To shift a synchronous engagement type multi-stage transmission comprising a main transmission and a sub-transmission to a shift stage adapted to a vehicle speed when shift operation is performed during neutral traveling. SOLUTION: When the shift operation is performed during neutral traveling, a wheel speed of a drive wheel, a range gear rotation speed of a range, i.e., the sub-transmission and the shift state of the range are read respectively (S1-S3), and the wheel speed and the range gear rotation speed are converted into rotation speeds vc1 and vc2 of a range counter shaft respectively (S4, S5). Further, if an absolute value of difference of the rotation speeds vc1 and vc2 (rotation speed deviation) is less than a predetermined value, a target shift stage is determined from the rotation speed vc1 (S6, S7). Whereas, if the rotation speed deviation is not less than the predetermined value, the target shift stage is determined from the larger one of the rotation speeds vc1 and vc2 at the time when the state is kept for a predetermined time (S6, S8, S9), and the operation of the multi-stage transmission and a friction clutch is controlled (S10). COPYRIGHT: (C)2008,JPO&INPIT