Multi V-grooved pulley structure and method of making same

A one-piece, sheet metal, multi V-grooved pulley structure including:

• a. a circular hub wall;
• b. an annular flange wall extending generally axially from the hub wall and terminating in an open end opposite the hub wall;
• c. a conical wall extending between and integrally joining the hub wall and the annular flange wall;
• d. a series of outwardly opening V-shaped grooves formed in the annular flange wall, said grooves each being defined by a pair of inwardly angled side walls, with each of the pairs of angled side walls increasing in metal thickness from the open end toward the hub wall of the annular flange wall;
• e. the V-groove forming angled side wall adjacent the conical wall having a double wall thickness;
• and
• f. a reentrant flange formed in the conical wall providing one wall thickness of the double thickness V-groove forming angled side wall.

A one-piece, sheet metal multi V-grooved pulley structure including:

• a. a circular hub wall;
• b. an annular flange wall connected with the hub wall and extending generally axially from the hub wall and terminating in an open end opposite the hub wall;
• c. a series of outwardly opening V-shaped grooves formed in the annular flange wall, said grooves each being defined by a pair of inwardly angled side walls;
• d. each of the pairs of angled side walls increasing in metal thickness from the open end toward the hub wall of the annular flange wall;
• e. the adjacent groove forming angled side walls of adjacent V-grooves being integrally joined by groove crests;
• and
• f. the metal thickness of the groove crests varying to provide for the differences in metal thicknesses of the adjacent groove forming angled side walls.

In a method of making a spun sheet metal pulley of the type having a bottom hub flange wall and an outer generally cylindrical side wall terminating in an open end, from a flat sheet metal disc blank, including the steps of:

• a. providing a flat sheet metal disc blank having a central hole formed therein;
• b. clamping a central portion of the disc blank around the hole between opposed relatively axially movable complementary clamping faces of rotatable first headstock and tailstock die means wherein the first headstock die means also includes cylindrical flange wall forming means having a series of cylindrical surfaces extending generally parallel to the axis of the headstock die means, and with said cylindrical surfaces having diameters increasing in dimension progressing away from the clamping face of the headstock die means;
• c. rotating the first die means and clamped disc blank;
• d. pressure rolling, forming and ironing an annular portion of the rotating disc blank metal surrounding the central portion against the first headstock die means cylindrical flange wall forming means to form a cup-shaped stage blank with a flat bottom hub flange wall and a connected axially extending generally cylindrical side wall, to form said side wall with a series of integral cylindrical sections, and to form said sections with decreasing metal thickness progressively away from the bottom hub flange wall;
• e. removing the formed cup-shaped stage blank from the first headstock die means;
• f. mounting the cup-shaped stage blank on second headstock die means;
• g. rotating the second headstock die means and cup-shaped stage blank;
• and
• h. roller forming a plurality of pairs of V-groove flanges in the cylindrical side wall by pressure forming and ironing the series of cylindrical sections against the second headstock die means to form each of said cylindrical sections with a pair of V-groove flanges providing adjacent V-shaped pulley grooves, whereby said pulley groove V-groove flange pairs decrease in metal thickness progressively away from the bottom hub flange wall.

In a method of making a spun V-grooved sheet metal pulley, including the steps of:

• a. pressure roll forming a bottom hub flange wall and a generally axially extending side wall terminating in an open end in a single flat sheet metal disc blank to provide a cup-shaped stage blank, and during the stage blank roll forming step providing a plurality of integral cylindrical sections of increasing metal thicknesses progressively in the cylindrical side wall from the open end toward the hub flange wall;
• b. trimming an extended end of the cylindrical side wall which defines the open end;
• and
• c. roller forming a plurality of V-grooves in the cylindrical side wall by pressure roll forming and ironing the metal in each of the several cylindrical sections into pairs of V-groove forming flanges;
• whereby the metal thickness of successive flange pairs increase progressively, from the open end toward the hub flange wall.