AUTOMATIC TRANSMISSION

摘要

An input shaft (1) connectable to an engine (5), an output gear (2), a transmission case (3) and a Ravigneaux planetary gear unit (4) are provided. Four rotational elements of the Ravigneaux planetary gear unit (4) are a single pinion side sun gear (Ss), a carrier (C), a ring gear (R) and a double pinion side sun gear (Sd) which are arranged orderly on a common speed diagram. The single pinion side sun gear (Ss) is constantly connected to a motor/generator (6), and the ring gear (R) is constantly connected to the output gear (2). And, with usage of a low & reverse clutch (L&R/C), a high clutch (H/C) and a low brake (L/B), a first speed (1st), a second speed (2nd), a third speed (3rd) and a stepless change speed (eCVT) are established.

主权项

1. An automatic transmission comprising:
an input member connectable to an engine; an output member; a fixed portion; and a planetary gear unit including four rotational elements, in which, the four rotational elements of the planetary gear unit are first, second, third and fourth elements which are arranged orderly on a common speed diagram; the first element is constantly connected to the motor/generator and connectable to the input member due to engagement of the first clutch; the second element is connectable to the input member due to engagement of the second clutch; the third element is constantly connected to the output member; the fourth element is fixable to the fixed portion due to engagement of the first brake; a first speed is established due to engagement of both the first clutch and the first brake; a second speed whose speed change ratio is smaller than that of the first speed is established due to engagement of both the first brake and the second clutch; a third speed whose speed change ratio is smaller than that of the second speed is established due to engagement of both the first clutch and the second clutch; and a stepless speed change that enables the speed change ratio to vary steplessly is established by engaging the second clutch and varying a rotation speed of the motor/generator.