Abstract: In the present invention, a thin and disc-shaped blank made of steel plate is used. The present invention provides a method of manufacturing a sheet metal member comprising a circular base plate, and an annular projection bulged from at least one surface of the base plate so as to be concentric therewith, which can be easily and cheaply produced without loss of material, by only a few steps. A blank having an outer peripheral portion which has been thickened by a former step, is rotated while it is held between an upper and lower dies. At the same time, an edge angle portion of an outer peripheral surface of a drawing roller is pressed against one surface of the thickened outer peripheral portion which extrudes outwardly from the upper die of the blank, and the drawing roller is rotated, while it is moved in the direction of the center of the blank, and the thickened outer peripheral portion is drawn so as to make it think, thereby bulging the annular projection axially.

Abstract: The present invention provides a method of manufacturing a poly-V pulley made of metal sheet, which can be easily produced from a thick flat-plate material. By this method, the poly-V pulley is formed to have a two-part arrangement of poly-V grooves having different diameters, i e., a small diameter and a large diameter. A circular flat-plate material having a boss portion at the center thereof is bent, thereby forming a first forming body whose section is dish-shaped. The first forming body includes a supporting base and a conical peripheral portion consecutively disposed so as to be inclined and widened from the outer peripheral end of the supporting base portion in the outward direction. Next, the conical peripheral wall is extended in the widening end direction so as to decrease the thickness thereof, thereby forming a second forming body whose section is also deep dish-shaped.

Abstract: The present invention provides a method of producing a poly-V pulley which can economically produce a poly-V pulley of the type that is to be inserted and coupled onto a shaft via a one-way clutch or a bearing, the number of steps being as small as possible. A trunk is obtained by cutting a thick pipe blank into a fixed dimension. Thereafter, first and second preliminary ears are projectingly formed in the axial ends on the outer peripheral face of the trunk by pressing in which the axial end faces of the trunk are clamped between upper and lower dies respectively having annular wedge-like projections, and the wedge-like projections bite the axial end faces of the trunk. The first and second preliminary ears are shaped into first and second ears by rolling of a predetermined shape, and poly-V grooves are thereby formed.