Multi-step planetary transmission, especially automatic transmission in vehicle, has clutches for selective engagement to effect different transmission ratios so that eight forward speeds and one reverse speed can be engaged

摘要

The multi-step planetary transmission, especially an automatic transmission in a vehicle, comprises a drive shaft (1) and an output shaft (2) installed in a gearcase (G), four planet trains (P1-P4), at least seven rotatable shafts (1-7), and at least five brakes (03-05) including shift elements, and clutches (17,47) for selective engagement to effect different transmission ratios between the drive shaft and output shaft so that eight forward speeds and a reverse speed can be achieved.