| 摘要 |
PROBLEM TO BE SOLVED: To provide a heat exchanger flat tube to be securely brazed to a header tank while maintaining sufficient pressure resistance, without increasing its manufacturing costs when forming the flat tube by bending plate materials. SOLUTION: The edge of the upper side plate material 13 constituting the upper side of the tube 2 is bent inward to a flow path at an approximately right angle and then turned around approximately 180°outward and backward to the flow path to form a turn-around portion 13a. On the other hand, the edge of the lower side plate material 14 constituting the lower side of the tube 2, arranged on the lower face of the upper side plate material 13 in opposition thereto, is bent outward along the turn-around portion 13a to be in contact with the end of the turn-around portion 13a to form a fitting portion 14a. The fitting portion 14a is formed in such a manner that there is no level difference on the outer face of an engagement portion 15 between the turn-around portion 13a and the fitting portion 14a. COPYRIGHT: (C)2004,JPO&NCIPI
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