METHOD FOR FORMING PULLEY FOR BELT TYPE CVT, AND PULLEY FOR BELT TYPE CVT FORMED WITH THE FORMING METHOD

摘要

PROBLEM TO BE SOLVED: To provide a method for forming a pulley for a belt type CVT, which is free from problems of residual stress, distortion and defect due to weld, has high strength, is uniform, reduced in weight, and inexpensive, by integrally forming a belt sliding surface part of a circular cone shape and a cylindrical shaft part from a raw material.SOLUTION: The method for forming a pulley for a belt type includes: tearing a disk-shaped raw material W0 from the outer peripheral surface toward the central part to a position corresponding to an outer peripheral surface of a shaft part 22 by using a tearing roller R1 while rotating the raw material W0; compressing one side W1b of the torn raw material W1 to reduce the diameter by using a forming roller R2; ironing a cylindrical shaft part W2b, formed by the forming roller R2, by using an ironing roller R3 while pressing to a mold D2 to form a cylindrical shaft part W3b; and ironing the other side W1a of the torn raw material W1 by using an ironing roller R4 while pressing to a mold D1 to form a belt sliding surface part W4a of a circular cone shape.