AUTOMATIC TRANSMISSION MECHANISM

摘要

PROBLEM TO BE SOLVED: To provide a multistage transmission mechanism capable of setting appropriate gear ratio of the whole transmission mechanism and a reduction gear ratio step of each gear stage so as to satisfy demand as an automobile and attaining miniaturization. SOLUTION: This automatic transmission mechanism comprises one simple planetary gear IP and a pair of ravigneaux-type planetary gears PU, and sun gears S1 and S2 are integrally connected to each other and a ring gear R1 and a carrier CR2 are integrally connected. First to sixth gears and reverse gear shown in the velocity diagram can be obtained by motion of each of clutches C-1 to C-2 and brakes B-1 to B-4 shown in the motion diagram. Appropriate gear ratio width and reduction gear ratio step are obtained by setting as shown in the figure of the gear ratioλ.