| 摘要 |
PURPOSE:To bring the whole inner circumferential surface of a small bore pipe into close contact completely, prevent the forming of an opening part causing gas leakage, and increase strength against lateral load by squeezing the small bore pipe part for sealing of a metal tube end part, which is placed on a concave receiving surface having smaller curvature than that of the pipe outer surface by means of a punch of which width covers the pipe. CONSTITUTION:One end of a metal pipe 10 as a heat pipe mainbody is sealed and noncondensable gas is exhausted and then specified working fluid is injected through a small bore pipe part 11 as the other end of the pipe 10. On a die as a receiving surface having a concave circular arc surface of which curvature is smaller than that of the part 11, the part 11 is placed in the axial direction of the die and it is processed in squeezing condition by a punch of which width W at the convex circular arc section of its tip part covers the part 11 wholly in its radius direction. Both ends of the pipe where the curvature is the largest in a squeezed part and an opening part is apt to be formed are positively folded in two with pressure. The pipe 10 to which squeezing process is applied is set up-right with the part 11 put at the upper side and then the tip part of the part 11 is molten with heat to finish sealing work. |
