| 摘要 |
PROBLEM TO BE SOLVED: To suppress the lowering of shift quality by accurately judging the power-on and the power-off, when a change gear rate becomes a judgment value or more, which is larger than the change gear ratio before the shifting and when it becomes a judgment value or less, which is smaller than the change gear ratio before the shifting. SOLUTION: An automatic transmission is provided with an input shaft for receiving a drive force from a drive engine, an output shaft transmitting the drive force to the wheel, a plurality of engagement elements setting power transmission characteristics between the input shaft and the output shaft, a detecting means for detecting change gear ratio calculated from the rotation speed of the input shaft and the rotation speed of the output shaft, and a control means for controlling the release and engagement of the engagement elements. When the change gear ratio(r) becomes a first judgment value Rup or more, which is larger than the change gear ratio before the shifting in reducing the oil pressure of the engagement element in the release side in downshift, this control means starts the power-on shift control and, when the change gear ratio(r) becomes a second judgment value Rdown or less, which is smaller than the change gear ratio before the shifting, the power-off shift control is started. |
