| 摘要 |
A pair of header plates 9 securely brazed with a pair of side plates 5 without causing any buckling to tubes 2 and any deformation to the header plates 5. First, each tube 2 is press-fitted into a corresponding press-fitting hole 12 in the header plates 5, and at the same time, the end parts of a pair of side plates 9 make contact with the pair of header plates 5. Second, flaring pins are press fitted into the end parts of the tubes in such a way that the end parts of the tubes 2 disposed near either side of a core assembly are flared to an angle of approximately 180 DEG and the end parts of the tubes 2 disposed in the central part of the core assembly are flared to an angle within a range from approximately 60 DEG to approximately 80 DEG . Third, cores 4, etc. are hung from either of the upper header plates 5, whichever is disposed at the upper side, and then this assembly is brazed. At this time, large widening parts with an angle of approximately 180 DEG can prevent the upper header plate 9 from sliding downwards. In this arrangement, the contacting state of the header plates 9 with the side plates can be maintained, whereby secure brazing can be performed. Although the flared angle is large for the tubes disposed near either side of the core assembly and large loads are applied thereto, as the large loads are received by the side plates 9, the tubes 2 disposed near either side will not be buckled. On the other hand, as the flare angle is small for the tubes 2 disposed in the central part of the core assembly and only small loads are applied thereto, the tubes disposed in the central part of the core assembly will not be buckled or the header plates 9 will not be deformed. <IMAGE> |
