TOOTH PROFILE SIZING METHOD

PURPOSE:To absorb an excess metal and to improve a tooth profile accuracy and tooth face accuracy by setting larger the corresponding diameter of the finishing tooth profile of a die, compared to the diameter of the tooth bottom circle of the tooth profile of an intermediate forming blank, and gradually decreasing the ironing allowance of the tooth face from the tooth root to the tooth end. CONSTITUTION:The diameter of the tooth tip circle of a rough tooth profile 12a is made larger by d1 compared to the corresponding circle diameter of a finishing tooth profile 7, and the diameter of the tooth bottom circle of the rough tooth profile 12a is made smaller by d2 compared to the corresponding circle diameter of the finishing tooth profile 7. According to a blank 12 being pushed in and subjected to ironing the metal of a tooth face 23 is flowed towards one direction from the tooth end for the tooth root. The face roughness is thus stabilized and improved. Also the excess metal is absorbed to the tooth bottom part and the excess metal pushed out in the axial direction is absorbed by the gap c2 formed between the corner part of the flange part 24 formed as a push residual part at the axial direction end of one part of the blank 12 and the rough tooth profile 12a, and a tapered chamfering 20. Both the tooth profile accuracy and tooth face accuracy can thus be improved.