| 摘要 |
PURPOSE:To always favorably control speed change when speed change operation is simultaneously performed in a main and a sub-transmissions by controlling the coupling force of a friction element for changeover of shift step in the normal driving condition of the sub-transmission, and controlling the coupling force of a friction element for engine brake in its reverse driving condition. CONSTITUTION:An automatic transmission 1 is constituted of a torque converter 10, a main transmission 20 arranged on the concentrical axis of it, and a sub- transmission 30 arranged on the parallel axis with the former. The sub- transmission 30 is provided with a single planetary gear mechanism 31, a direct coupling clutch 32 is arranged between the ring gear 31a and the sun gear 31b, and a one-way clutch 33 and a deceleration brake 34 are arranged between the sun gear 31b and a transmission case 3. In this case, when speed change operation is simultaneously performed in the main and sub- both transmissions and the sub-transmission 30 is in the normal driving condition driven by engine output for example, the direct coupling clutch 32 is controlled so as to change the gear ratio of the sub-transmission according to change of gear ratio of the main transmission 20. |
