VERFAHREN ZUR SCHALTREGELUNG EINES AUTOMATIK-GETRIEBES UND SCHALT-REGELSYSTEM DAFUER

摘要

An automatic transmission has a sub-transmission and a main transmission disposed on the engine side and on the driven wheel side in series. The sub-transmission and the main transmission are each comprised of a planetary gear mechanism so as to allow the sub-transmission to assume two speed range modes including low and high speed ranges and the main transmission to assume three speed range modes including low, intermediate and high speed ranges. When the automatic transmission is downshifted from the fifth to the third speed range mode, both of the sub-transmission and the main transmission are downshifted. In this case, the sub-transmission is downshifted from the high speed range to the low speed range. While the main transmission is downshifted from the high speed range to the intermediate speed range. In the downshifting from the fifth to the third speed range, a gear ratio of the sub-transmission between prior to and subsequent to the shift is set to be smaller than that of the main transmission. When the sub-transmission and the main transmission are both shifted in the same direction, the transmission having a smaller gear ratio is delayed.