This method for manufacturing pipe has: a first step for fabricating a first bottomed cylindrical body (12) by a first backward extrusion process that strikes a first punch (11) onto work from a first direction; a second step for fabricating a second bottomed cylindrical body (14) by carrying out a second backward extrusion process that strikes a second punch (13) onto the first bottomed cylindrical body (12) from the first direction with the inside surface of the first bottomed cylindrical body (12) as a guide; and a third step for fabricating a first cylindrical body (16) having a through hole (16a) by opening a hole in the bottom of the second bottomed cylindrical body (14).
B21C 37/06 - Fabrication de tôles, barres, fils, tubes ou profilés métalliques ou de produits semi-finis similaires, non prévue ailleursFabrication de tubes de forme particulière des tubes ou tuyaux métalliquesProcédés combinés pour fabriquer des tubes, p. ex. pour fabriquer des tubes à parois multiples
B21J 5/06 - Méthodes pour forger, marteler ou presserÉquipement ou accessoires particuliers pour effectuer des opérations particulières
B21K 21/00 - Fabrication d'articles creux, non couverte par un seul des groupes
[PROBLEMS] A method of producing a ball joint, in which, in reducing of the diameter of a wall of a socket in production of the ball joint, parting lines and wrinkles are not produced on the outer surface of the socket and which appropriately controls a clearance between the socket and a ball section. [MEANS FOR SOLVING PROBLEMS] A first member (12) having a ball section (14) of a ball joint (10) and a second member (15) having a socket (16) are supported with the ball section (14) received in the socket (16). A pair of dies (20, 30) holds, from the radially outside, the wall (18) surrounding an opening (17) of the socket (16) and intermittently presses the wall (18) radially inward by gradually approaching the wall while performing quick vibration of repeated approach and retract motions. At each interval of the intermittent pressing operation, a support and rotation device (40) rotates the socket (16)(second member (15)) by a small distance about the center axis (C2) of the socket (16). Thus, the dies (20, 30) sequentially press a large number of points on the entire circumference on the outer surface of the wall (18) of the socket (16), and as a result, the wall (18) is bent inward to reduce its diameter.
F16C 11/06 - Articulations à rotuleAutres articulations ayant plus d'un degré de liberté angulaire, c.-à-d. joints universels
B21D 39/00 - Utilisation de procédés permettant d'assembler des objets ou des parties d'objets, p. ex. revêtement par des tôles, autrement que par placageDispositifs de mandrinage des tubes
B21D 53/00 - Fabrication d'autres objets particuliers
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