| 摘要 |
PURPOSE:To obtain a product with a general-purpose press and without requiring removal of an excess metal by machining by combining a stage for obtaining a semi- processed product having the excess metal slightly in a diametral direction with a special die design and a finishing stage for drawing the excess metal. CONSTITUTION:Top and bottom dies 11, 12 have spherical faces 13a, 13b conforming approximately to the outside circumferential surface of a product. The face 14a conforming to the race face of the product is formed in the deep side of the die 11, and the center Q of the curvature thereof is positioned innerly by L from a die parting face 11'. A perpendicular plane part 15 is provided between the plane inclusive of the point Q and the face 11'. The face 14b of the die 12 is slightly expanded diametrally on the die parting face 12' side and when both dies are mated, the face 14b is gently connected to the part 15. A rough material 1 set in the die 12 is pressed by both dies and is expanded diametrally outward, thereby obtaining the semi-processed product wherein the base of a ball groove 15 in the central part has an excess metal 17 slightly larger in diameter than the race face 16 of the product. No burrs, etc. are produced at the mating faces of the dies in this state. The excess metal 17 of the semi-product is drawn by top and bottom dies 21, 22 having 22, 23 conforming to the outside circumferential surface and race face of the product, whereby the product having a prescribed size and shape is obtd. |
