Patent ID: 7458912
Filing Date: 2008-12-02
Classification: F16H

Abstract:
1. An automatic transmission comprising: a planetary gear train including first, second, third and fourth planetary gears arranged in order of mention from an input shaft's side toward an output shaft's side, the first and second planetary gears being combined to form a planetary gear set in which two of three rotating elements of the first planetary gear are connected, respectively, with two of three rotating elements of the second planetary gear; an input rotation member which extends from an input shaft radially outwards between the second and third planetary gears and which is connected with a ring gear of the second planetary gear; a first connection member including a first end portion connected with a carrier of the second planetary gear between the first and second planetary gears, a second end portion connected with a ring gear of the fourth planetary gear, and an intermediate portion surrounding the second and third planetary gears; an engaging device group to determine a gear ratio of the planetary gear train; a first rotation sensor to sense a rotation speed of a first rotary member which is the first connection member; a second rotation sensor to sense a rotating speed of a second rotary member which is a rotating element of the planetary gear set and which is arranged to rotate at a speed different from the rotating speed of the first connection member; and a processing section to calculate a rotation speed of the input shaft from the rotating speeds sensed by the first and second rotation sensors.