| 摘要 |
PURPOSE:To prevent production of void at a joint between a tube and an end plate, by a method wherein an insertion hole having a cylindrical burring part serving to securely insert the tube into the end plate is formed, and the tip part thereof is expanded at a portion, positioned facing the dent part of the tube, of the burring part. CONSTITUTION:A plurality of dent parts 104, protruded from the outer surface of a tube toward the inner surface thereof, are formed at specified intervals on a flat tube 105. An insertion hole 101a for the tube 105 is formed in an end plate 101, a burring part 102 is formed to the opening edge of the insertion hole, and a tip part 103 is expanded in a direction in which the tip part is parted away from the tube 105, inserted into the insertion hole 101a, i.e. in a direction in which the inner diameter of the insertion hole 101a is enlarged. By filling a space between the insertion hole 101a and the tube 105 with solder 106, air present between the inner wall of the insertion hole 101a and the dent part 104 is rapidly exhausted through the enlarged tip part 103 without remaining. |
