AUTOMATIC TRANSMISSION

摘要

PROBLEM TO BE SOLVED: To ensure a responsiveness more favorably further, while ensuring a compact property. SOLUTION: The small diameter side cylindrical part 23b of a second servo piston 23 for backward stage is arranged oil tightly and slidably in an axis direction on the outer periphery surface of the small diameter side cylindrical part 24b of a drum member 24 connected to an input shaft and a big diameter side cylindrical part 23a is arranged oil tightly and slidably in the axis direction on the inner periphery surface of the big diameter side cylindrical part 24a of the drum member 24. The small diameter side cylindrical part 22b of a first servo piston 22 for forward start stage is arranged oil tightly and slidably in the axis direction on the outer periphery surface of the input shaft 2 and the big diameter side cylindrical part 22a of the first servo piston 22 is arranged oil tightly and slidably in the axis direction on the inner periphery surface of the big diameter side cylindrical part 23a of the second servo piston 23. Thus, the first/second servo pistons 22, 23 are constituted by a double piston structure.