| 摘要 |
PURPOSE:To enable safe and reliable control of a continuously variable transmission by maintaining the gear ratio to the first set value in detecting of failures when the detection of the vehicle speed is abnormal, and maintaining the gear ratio to the second set value on the low side according to the decrease of the engine speed after abnormality is detected. CONSTITUTION:In a control circuit 20 of a continuously variable transmission, the abnormality of a vehicle speed detecting signal is detected. In the normal state, the normal transmission processing is applied, and the drive pulley pressure P1 is controlled as a function of the vehicle speed (v) and the throttle opening gamma, and the driven pulley pressure P2 is controlled as a function of the gear ratio and a torque T. While, in failures, whether or not the drive pulley rotational number is the specific value or less is judged. When the result is YES, the drive pulley pressure P1 is made into the minimum pressure, and the drive pulley diameter is made into the specific minimum diameter, moreover the driven pulley pressure P2 is made into the maximum pressure, and the drive pulley diameter is made into the specific maximum diameter, the gear ratio is restored to the low side. When the result is NO, respective pulley pressures are maintained to the value just before the failures. |
