Abstract: A method is disclosed for forming helical or spur gears. The method comprises providing a die having a toothed region, positioning a first blank in the toothed region of the die, inserting second and third blanks adjacent the first blank, and applying a force to the third blank. The toothed region of the die includes die teeth projecting into an internal bore of the die, and the force is applied to the third blank to move the second blank through the die until a leading end of the third blank is generally coincidental with a minimum diameter portion of the toothed region. During the application of force to the third blank, the second blank is moved through the toothed region of the die to form external teeth in the blank, and the first blank is ejected from the toothed region.

Abstract: A extrusion die assembly for cold extruding internally and/or externally toothed gears and the like, particularly internally toothed ring gears, with the mandrel for forming the internal teeth in the workpiece including axially successive sets of die teeth, with each set including a full complement of annularly arranged and equally spaced die teeth, and the die teeth from the leading set to the trailing set increasing progressively in diameter.In one embodiment, the die teeth from one set to the next on the mandrel extrude the gear teeth in equal radial depth, and in a second embodiment, the die teeth of each succeeding mandrel set extrude the gear teeth by displacing an equal volume of material from one set to the next.

Abstract: An internally toothed die which has the entire root to pitch diameter of its die tooth tip material removed in the transition zone between the land area and the trailing relieved portion; this essentially redistributes the extrusion bending forces without sacrificing helical workpiece guidance, dimensional control, or surface integrity during extrusion of an externally helically toothed gear. It provides a relieved portion that has a leading scallop with a spherical radius and a trailing portion that is linear but tangent to the spherical radius.

Abstract: A forging die and a forging die manufacturing method for extruding helical gears wherein the lead end face of each die tooth is made up of harmonious S-shaped curves with each curve having maximized-radii contours. The shape of the S-shaped curves is formed by dividing the cylindrical surface at the lead end face and the full depth perimeter into an equal number of equally spaced points, connecting these points up into pairs so as to establish the shortest distance between the pairs of points and using these pairs as the end points for the S-shaped curves.

Abstract: A method of preparing a gear blank for roll-finishing, essentially comprising the step of: while supporting a gear blank with pitch-line chucking, finish-sizing the central axial opening of the gear blank to a desired concentricity to promote accurate subsequent roll-finishing. Also, a method of making roll-finished gears, comprising: (a) preparing a near-net-shape gear blank, with external gear teeth and a central axial opening, by intimately engaging and supporting the gear blank between two opposing roll-finishing gear dies, without teeth finishing pressure; (b) finish-sizing the sides of said axial opening to attain a concentricity between the gear blank's intended tooth pitch circle and said sized sides that is within the range of 0.

Abstract: A cold extrusion process for forming internal ring gears comprising the formation of an annular ring gear blank having precise inside and outside diameters, placing the workpiece over a circular mandrel having external gear forming die teeth and a pilot portion adapted to receive the blank, placing a die ring around the mandrel and the assembled workpiece, a circular punch arranged coaxially with respect to the mandrel and the workpiece, moving the punch into the annular space occupied by the workpiece between the die ring and the mandrel, advancing the punch by means of a press whereby the workpiece is cold formed through the external teeth of the mandrel, moving the die ring in synchronism with the downward motion of the workpiece through the die teeth thereby eliminating any frictional forces in the direction of motion of the die during the extrusion process, and retracting the die ring following the extrusion of the workpiece thereby permitting automated ejection of the workpiece.

Abstract: A die for use in extruding helical gears includes a die orifice at the upper end of the die teeth where the extrusion blank first enters the die. Each tooth is formed with a land directed parallel to the helix on the drive and trail side of the tooth and an end face perpendicular to the helix that intersects either a transition surface, directed perpendicular to the die axis, or a land. Alternatively, the end face can extend entirely across the tooth width from one land to the other without the use of the transition surface. Relief surfaces slope inwardly from the land and provide spaces within which the extrusion blank may expand without undue frictional contact with the die.

Abstract: A sleeve having a tapered outer surface is shrink or interference fitted over the outer surface of a die blank in which is formed a central bore, a larger diameter bore and a transition bore therebetween. The diametrical interference between the sleeve and the die blank is effective in producing an elastic deformation of the smaller diameter bore causing it to assume a conical shape. The die blank and sleeve are restrained within a casing and the inner surface of the die is formed by electrical discharge machining, electrical chemical machining or by other known methods. The die casing and sleeve are removed from the die, allowing the release of the stored strain energy of deformation which causes the smaller bore of the die to assume a conical shape tapering radially outwardly from its inner extremity. The sharp corner that results at the innermost end of the smaller bore is removed by lapping a straight-sided tool through the central opening of the die.