Patent ID: 6892804

Claim:
A heat exchanger comprising: a plurality of tubes in which fluid flows; fins joined to outer surfaces of the tubes for facilitating heat-exchange between fluid flowing round the tubes and fluid flowing in the tubes; header tanks arranged at end portions of the tubes extending in a direction perpendicular to a longitudinal direction of the tubes and communicating with the plurality of tubes; the header tanks including core plates to which the tubes are joined, the header tanks also including tank bodies caulked and fixed to the core plates by plastically deforming caulking portions provided on the core plates, wherein: an outer portion to be plastically deformed on an end of the caulking portion has a reduced wall thickness that is less than that of the other portions of the caulking portion; the outer end having the reduced wall thickness extends from the end of the caulking portion to a position beyond a bent portion of the caulking portion; a stepless internal surface of the caulking portion is disposed on the tank side; a stepped outer surface of the caulking portion is disposed on a side opposite to the tank side to form the reduced wall thickness of the outer portion; and the bent portion is disposed in the reduced wall thickness of the outer portion.