| 摘要 |
PURPOSE:To reduce the shock due to the speed change operation, and perform the speed change operation smoothly at the time of speed change for required reset by resetting the connected condition of each friction element of both a main and an auxiliary transmission to the predetermined speed step under the condition that the released condition of a friction element for an engine brake is maintained. CONSTITUTION:An automatic transmission 1 consists of a torque converter 10, a main transmission 20 arranged on the same axis as the torque converter 10, and an auxiliary transmission 30 arranged in parallel with these axes. In this case, at the time of speed change for the required reset, the connecting pressure of a 3-4 brake of the main transmission 20 is raised, and on the other hand, the connecting pressure of a direct connecting clutch 32 of the auxiliary transmission 30 is discharged, and the connecting pressure is supplied to a speed reduction brake under the released condition to reset the speed step to a high speed step. A coast brake 29 of the main transmission 20 is maintained under the released condition. A vehicle is thereby under the transient idle travelling condition to reduce the shock due to the speed change operation. Thereafter, the coast brake 29 is connected to provide the engine brake condition. |
