| 主权项 |
1. A heat exchanger production method, utilizing a tube-grasping body for grasping an insert tube in a heat exchanger, the method comprising:
a first process wherein
an enlargement portion having a prescribed length is formed, by inserting a tube-enlarging mandrel by a prescribed depth, from an opening of an insert tube being inserted into a heat radiating fin of a heat exchanger; a second process wherein
an exterior of said enlargement portion is surrounded and connected, by the tube-grasping body wherein
tube-contacting parts, capable of radially expanding or axially compressing, are formed and separated by a plurality of slits each of which is of a prescribed width, and which are formed in a longitudinal direction of the tube-grasping body, the same direction of the movement of the tube-enlarging mandrel; andthe width of each of said slits is gradually increased from said prescribed width to an expanded width, from a prescribed location toward the opening of said tube; a third process wherein
a circumferential surface of the enlargement portion of the tube is firmly grasped and supported by tube-contacting parts, as a diameter of each of the tube-contacting parts is reduced in an axial direction to gradually reduce the expanded width which has been expanded from the prescribed width from a prescribed position of the slit, by a sliding means pressing a slopes of the tube-contacting parts, while sliding, toward the opening of the corresponding tube, along the same slopes which are slanted in a widening direction toward the opening of the tube; and a forth process wherein,
in the state where the circumferential surface of the enlargement portion of the tube is firmly grasped and supported by the tube-contacting parts, the tube-enlarging mandrel is further inserted into the tube to join the heat radiating fin and the tube together. |
