Method of making poly-v pulleys

Abstract

A sheet metal poly-V pulley is made by forming a cup-shaped blank having a cylindrical wall with inner and outer peripheral surfaces, thickening the cylindrical wall by compressing the blank axially while rolling it, then rolling the thickened blank on shaped rollers to form corresponding inter-spaced inner and outer grooves. The outer grooves are deep V-shapes impressed with rollers; the inner grooves are shallow V-shapes formed by pressure against the surface of a rotary support for the cup shaped blank during rolling. The plurality of parallel V-shaped annular grooves in the outer peripheral surface receive poly-V belts, and the plurality of smaller V-shaped annular grooves on the inner peripheral surface are aligned between the outer partition walls and cause more-precise positioning of the outer grooves. Flared flanges are formed at opposite ends of the thickened portion projecting radially beyond the partition walls, the flanges having stepped, cut-out portions for receiving the edges of poly-V belts.