| 摘要 |
PROBLEM TO BE SOLVED: To prevent a tooth flank of each gear in a planetary gear of an automatic transmission from being locally worn and deteriorating in tooth contact. SOLUTION: The automatic transmission mechanism 7 comprises the planetary gear 11 and a plurality of clutches C1, C2, C3 and brakes B1, B2, B3 for selectively switching an operating state of the planetary gear to form a plurality of gear stages. In a condition that a gear stage detection means 25 detects a gear stage in which the planetary gear rotates in its entirety, a control means 20 switches the respective clutches or brakes for temporarily changing the gear stage to another gear stage. Switching of the respective clutches or brakes is preferably done when driving above a predetermined vehicle speed in the gear stage in which the planetary gear integrally rotates beyond a predetermined time duration and when transmission power of the automatic transmission is reduced in the case of braking or the like. COPYRIGHT: (C)2004,JPO |
