| 摘要 |
First depressed portions are formed on transverse sides of an insert so that the magnitude of depression of the first depressed portions increases as the first depressed portions approach toward the associated transverse side of the insert, whereby, as the first depressed portions are located to constitute a lower side of a core when brazing (in an oven), a brazing material, which is fused and is then allowed to flow into the first depressed portions in a brazing process, can be accumulated for retention within the first depressed portions by the surface tension of the brazing material so accumulated therein. Consequently, as the dispersion of more of the brazing material to outer fins, which constitute the lower side of the core when brazing, can be prevented, the erosion of the outer fins, which would otherwise occur due to the dispersion of the brazing material, can be prevented. |
