| 摘要 |
A tube insertion structure of a heat exchanger includes a header tank (120) having a tube hole (121a), and a tube (111) having a rectangular cross-section inserted in the tube hole (121a) at a longitudinal end (111a) with an abutment portion (131) of the tube (111) brazed to the tank (120). A narrow side (111b) of the rectangular flat section of the tube (111) is expanded outwardly into a protruding arc shape in close proximity of the abutment portion (131) of the tube (111). The arc shape on the narrow side of the tube is formed simultaneously in a mouth of the tube (111) expansion process. In this manner, a durable rooted structure near the tube insertion portion of a heat exchanger with reduced suction friction of fluid flowing in the tube (111) is provided. <IMAGE> |
