| 摘要 |
<p>Tubes (3) are formed in a flat tube shape, protrusions (7) which protrude toward the outside of the tubes are formed on one flat surface of each of the tubes, and recesses (8) which are recessed toward the inside of the tube are formed in the other flat surface of the tube. If one of the tubes which are adjacent to each other with a fin (4) provided therebetween is referred to as a first tube (3a), the other of the tubes is referred to as a second tube (3b), and both the distance between protrusions adjacent to each other in the longitudinal direction of the tube and the distance between the recesses adjacent to each other in the longitudinal direction of the tube are referred to as a dimple pitch (DP), the first tube and the second tube are arranged so that the one flat surface of the first tube and the other flat surface of the second tube face each other across the fin, and so that the protrusions provided on the first tube and the recesses provided in the second tube are arranged in such a manner that the positions of the protrusions and recesses in the longitudinal direction of the tubes are displaced from each other by half the dimple pitch.</p> |
