PISTON RETURN SPRING DEVICE FOR AUTOMATIC TRANSMISSION

摘要

PROBLEM TO BE SOLVED: To prevent the occurrence of radial fall as a hub forms a press-molded hub and to improve a material yield of a plate used to prevent the occurrence of a radial fall, in a piston return spring device for an automatic transmission having a return spring located between the hub and a piston by using the hub as a retainer. SOLUTION: A hub used as a retainer forms a press-molded hub 52 manufactured by press-molding a plate. In each of a plurality of coil springs of which a return spring 55 consists, a division plate 56 wherein four plates are aligned in an annular state to form a circular ring, is caulked for integral formation. The division plate 56 where the return springs 55 are integrally formed is supported such that the inner surface 52c of the press-molded hub 52 forms an axial direction support surface. This way locates the return spring 55 between the press molded hub 52 and a piston 54.