OUTER RACE OF CONSTANT VELOCITY JOINT AND ITS MANUFACTURING METHOD

PURPOSE:To efficiently manufacture the outer race for a constant velocity joint having an enough effective length and good concentricity through forging by inserting the respective punches into prepared hole on both sides of an intermediate wall and finish-forming track grooves and a serration part respectively. CONSTITUTION:A cylindrical billet 28 is extruded and upset in combination to form preformed body 30 provided with a cup part 12 having a prepared hole 32 and an axial part 14 having a 2nd prepared hole 34 through an intermediate wall 26. Then, a 1st punch 42 is inserted into the 1st prepared hole 32, a die 44 is lowered to iron the preformed body 30 from its outer peripheral surface and track grooves 16a-16c copying the 1st punch 42 are formed on the inner peripheral surface of the cup part 12. Thereafter or simultaneously with this, a 2nd punch 46 is forced into the 2nd prepared hole 34 to form a serration part 18 on the inner peripheral surface of the axial part 14. Thus, the outer race 10 for a constant velocity joint having, with good concentricity precision, the serration part 18 and the track grooves 16a-16c capable of securing an enough effective length by the intermediate wall 26 is obtained by forging only.