Abstract: A disk for a half toroidal type continuously variable transmission is manufactured through the following processes. In step S1, a work as a base material mass is heated to a temperature suitable for forging. In step S2, the work is forged into the work having a portion corresponding to a protrusion of the disk using a first die set. In step S3, the work is forged into the work which has a hole corresponding to a mounting hole of the disk using a second die set. In step S4, the work is forged into the work which has a portion corresponding to a skirt portion of the disk using a third die set. In step S5, the work receives punching, machining and the like to finally obtain the disk product.

Abstract: A power roller of a power roller bearing in a half-toroidal type continuously variable transmission is manufactured as follows. In step S1, a work used as material is heated up to a temperature suitable for forging. In step S2, the work is pressed by using a first die set, with its end face being held. In step S3, the work is forged by using a second die set. The work is formed into a work having a curved face corresponding to a traction surface, a hole corresponding to a center hole, and a recess corresponding to a raceway groove. In step S4, the work is punched by using a third die set. In step S5, the work is subjected to a cutting process and a heating process, thereby obtaining the power roller.

Abstract: The disk has a traction surface having a concave-arc-shaped cross section which is interposed between a small diameter end portion and a large diameter end portion. In the central portion of the end face of the disk on the small diameter end portion side, there is formed a through hole which extends through the disk up to the large diameter end portion side end face of the disk, while the inner peripheral surface of the through hole is used as an inside diameter surface of the disk. Here, when, among metal flows existing in the disk, a metal flow, which has such a positional relationship with respect to the surface of the disk that an angle .theta. formed between a metal flow on the traction surface side and the tangent of the traction surface is smaller than or equal to 30 degrees, is defined as a "metal flow along the disk surface", the disk is structured such that the "metal flow along the disk surface" exists at least in the traction surface.

Abstract: The disk has a traction surface having a concave-arc-shaped cross section which is interposed between a small diameter end portion and a large diameter end portion. In the central portion of the end face of the disk on the small diameter end portion side, there is formed a through hole which extends through the disk up to the large diameter end portion side end face of the disk, while the inner peripheral surface of the through hole is used as an inside diameter surface of the disk. Here, when, among metal flows existing in the disk, a metal flow, which has such a positional relationship with respect to the surface of the disk that an angle ? formed between a metal flow on the traction surface side and the tangent of the traction surface is smaller than or equal to 30 degrees, is defined as a “metal flow along the disk surface”, the disk is structured such that the “metal flow along the disk surface” exists at least in the traction surface.