| 摘要 |
PURPOSE:To provide a tube for heat exchanger such as automotive radiators with preferred inward protrusions by disposing the protrusions protruding inward ly into the tube on one side of the center line on one flat side, and on the other side on the opposite flat side. CONSTITUTION:On one of the flat sides of a tube 102, a plurality of protrusions 200a are formed on one side 204a of the center line l of the tube width. The protrusions 200a protrude inwardly into the tube. A plurality of protrusions 200b are formed, similar to the protrusions 200a, on the other side 204b of the center line l of the other flat side of the tube 102. The tube 102 is formed into a tube by folding a strip metal and joining the ends by seaming. The core metal 300 forms the tube with inward protrusions. Since the protrusions do not face each other, the core metal 300 can be made thick, and, along the core metal, the tube can be formed with preferred inward protrusions. |
