| 摘要 |
PROBLEM TO BE SOLVED: To provide an automatic transmission for a vehicle, which automatic transmission can achieve an excellent speed ratio of 1.1 or higher between respective speed changing steps without enlarging the size in the radial direction in the automatic transmission for achieving multi-stage speed changing by a speed changing output mechanism using two step speed reduction ratios from a speed reduction output mechanism. SOLUTION: In the speed reduction output mechanism 20 of the automatic transmission 1<SB>1</SB>for the vehicle, a first planetary gear set PS1 is configured by a first planetary gear DP0 and a second planetary gear DP1 composed of two double pinion type planetary gears, and also is configured by four rotary elements including a first sun gear S0 and a second ring gear R1 by connecting a first carrier CR0 and a second carrier CR1 with each other, and also by connecting a first ring gear R0 and a second sun gear S1 with each other. By this configuration, two step speed reduction ratios to be output from the speed reduction output mechanism 20 are equalized, and the speed ratios between the respective speed changing steps become excellent. COPYRIGHT: (C)2008,JPO&INPIT
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