| 摘要 |
PROBLEM TO BE SOLVED: To improve the drivability whtout deteriorating the running stability of a vehicle, by prohibiting the shift of a speed shift step when the shift of the speed shift step deteriorates the running stability of the vehicle, but permitting the shift when the shift does not deteriorate the running stabiliey of the vehicle. SOLUTION: In this change gear control device of an automatic transmission, an object speed shift step Rt is found depending on the running condition of a vehicle (Step 20), and the speed change control is carried out to make the speed shift step to the object speed shift step Rt. The slip angleαr of a driving wheel is found (Step 40), the slip ratio Sr of the driving wheel at the object speed shift step is inferred (Step 50 to 70), it is decided whether the slip angle and the inferred slip ratio are within a limit friction circle or not (Step 80), and the shift control to the object speed shift step is executed only the above dicision is in the affirmative. |
