| 摘要 |
PURPOSE:To obtain joining resistible to pulling force by forming an annular concave groove on the same circumference of a joining member and a joined member and forming a pyramidal convex piece over the whole circumference on the bottom of at least one of the two and joining by making the joining member plastic flow in the concave groove. CONSTITUTION:For instance, an annular concave groove 1b is formed on the circumference of a joined member 1 and a nearly pyramidal convex piece 1c is formed on the bottom face of the concave groove 1b over the whole circumference. Next, the joined member 1 is placed in a discoid hollow of the joining member 2 and the hollow part is pressed from above by a plunger punch (c) having annular pressing teeth (c1) on the pressing face. Consequently, the joining member near the hollow part makes plastic flow over the whole groove 1b and the joining member 2 and joined member 1 are united in a body. |
