Abstract: A method of manufacturing a sheet metal poly-V pulley including forming a tubular peripheral wall integrally from the peripheral edge of bottom wall and forming poly-V grooves in the peripheral wall at specified pitches, in which a bent part is formed in the bottom wall in an annular form concentric with the axial center of the peripheral wall and bulging out in a convex form toward the opening side of the peripheral wall. The load from the poly-V belt which may cause plastic deformation of the sheet metal poly-V pulley is absorbed by this bent part, so that the increase of material cost, difficulty in forming, and increase of weight due to increase of the thickness of the blank of sheet metal poly-V pulley in order to enhance the strength may be avoided.

Abstract: A sheet metal poly-V pulley and a method of manufacturing the same, having a tubular peripheral wall integrally formed from the peripheral edge of bottom wall and having poly-V grooves formed in said peripheral wall at specified pitches, in which a bent part is formed in said bottom wall in an annular form concentric with the axial center of the peripheral wall and bulging out in a convex form toward the opening side of the peripheral wall. The load from the poly-V belt which may cause plastic deformation of the sheet metal poly-V pulley is absorbed by this bent part, so that the increase of material cost, difficulty in forming, and increase of weight due to increase of the thickness of the blank of sheet metal poly-V pulley in order to enhance the strength may be avoided.

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.

Abstract: A method of manufacturing precise sheet metal made poly-V pulleys with poly-V grooves, being uniform in thickness of peripheral wall and free of reduction of mechanical strength, by a step of preliminarily forming a lug in the peripheral wall of a cup-shaped blank and thickening the peripheral wall, a step of forming a plurality of V-grooves in a multiple arrangement on this thickened peripheral wall by pressing from both sides with a V-groove preliminary forming roller possessing a plurality of V-grooves forming ridges and a rotary inner die possessing a plurality of V-grooves while rotating the cup-shaped blank, and a step of pressing this peripheral wall with a plurality of V-grooves with a finishing roller. Furthermore, a method of manufacturing sheet metal made poly-V pulleys having advanced precision, by a step of preliminarily forming lugs and first grooves in the peripheral wall of a cup-shaped blank, and a step of thickening the peripheral wall.

Abstract: An improvement in a method of manufacturing poly-V pulleys made of sheet metal, which is performed by subjecting a preformed cupshaped blank to working by a corrugating roller, an auxiliary forming roller and a finish forming roller. Prior to corrugation of the blank by the corrugating roller, a connecting portion between the peripheral wall and the bottom wall of the blank is pressed in a manner that the inside surface of the peripheral wall and the inside surface of the bottom wall are pressed into contact with each other, thereby to preform a lug which provides a side wall for grooves adjacent to the connecting portion.

Abstract: A sheet metal poly-V pulley formed from a cup-shaped blank having a cylindrical wall with inner and outer peripheral surfaces, the pulley comprising: at least a portion of the cylindrical wall being thickened with material from the blank, the thickened portion having a plurality of parallel V-shape annular grooves in the outer peripheral surface, separated by parallel, annular partition walls, the alternating annular grooves and partition walls being adapted for receiving poly-V belts; the inner peripheral surface of the thickened portion having a plurality of small V-shape annular grooves arranged parallel to one another and centrally aligned with the partition walls of the outer peripheral surface; and, annular flanges at opposite ends of the thickened portion projecting radially beyond the partition walls, the flanges having stepped, annular cut-out portions to prevent contact between the pulley and lateral edges of poly-V belts.