Patent ID: 6536257
Filing Date: 2003-03-25
Classification: B21J,B21K,Y10T

Abstract:
A speed-changing gear manufacturing apparatus, comprising:a die comprising a plurality of separate die elements located at regular intervals circumferentially of a forming position of gear material, wherein the number of said die elements corresponds to the number of spline teeth to be formed on the gear material; said plurality of die elements having respective spline teeth forming units for forming back-tapered spline teeth on the gear material along lines extending radially from a center axis of the gear material, said spline teeth forming units having an outer circumferential face; a die element holder for holding said die elements along the circumference of the forming position in an annular form and enabling said die elements to move along the lines extending radially from the center axis of the gear material; a sliding surface on an inner circumferential side of each of said die elements; a fixed die element retainer slidably engaging and retaining said sliding surface of each of said die elements; and a pressing member for moving said spline teeth forming units toward the center axis of the gear material by pressing said outer circumferential face of said spline teeth forming units of said plurality of dies; wherein said spline teeth forming units are constructed such that open spaces are formed between adjacent spline teeth forming units, in which open spaces both side faces of spline teeth of the gear material can be formed with a back-tapered shape at the same time as the tips of the spline teeth are formed with a chamfered shape, with adjacent ones of said spline teeth forming units contacting each other, by moving said spline teeth forming units toward the center axis of the gear material.