Heat exchanger

A heat exchanger assembly before brazing to be heated by a heating fluid, comprising:

• a box-shaped casing through which the heating fluid flows inside;
• on a premise that two orthogonal directions, intersecting a flow direction of the heating fluid within the casing, are defined as an X-axis direction and a Y-axis direction, respectively;
• a plurality of heat-absorbing fins stacked and arranged in the X-axis direction inside the casing;
• and
• a plurality of heat-absorbing tubes piercing through each of the heat-absorbing fins in the X-axis direction and through side plates on both sides in the X-axis direction of the casing, and through which a fluid to be heated flows insides,
• wherein through holes that are opened in each of the heat-absorbing fins and through each of which a corresponding heat-absorbing tube pierces are configured by a burring processed hole with which a burring wall protruding in the X-axis direction from a hole edge of each of the through holes is provided,
• wherein each of portions positioned at one side on both of upstream and downstream sides in the flow direction of the heating fluid of the respective through holes is formed into a missing portion at which a part of the burring wall has been removed,
• wherein each of the heat-absorbing fins is provided with brazing material holding portions positioned adjacent to the corresponding missing portion in the flow direction of the heating fluid, and
• wherein each of the brazing material holding portions is positioned above the corresponding through hole, and formed, in a state before brazing, to hold a brazing material with substantially the entire width in the Y-axis direction by extending above the corresponding missing portion at a predetermined distance, such that when melted, a molten brazing material is guided and penetrates between each of the burring walls and corresponding the heat-absorbing tube through the respective missing portions,
• wherein:
• each of the heat-absorbing fins is provided with a notched portion positioned on each side in the Y-axis direction of the respective brazing material holding portions, and
• the notched portion, being positioned relative to each brazing material holding portion, is formed to concave downward beneath the corresponding brazing material holding portion and portions of each of the heat-absorbing fins directly adjacent on outer sides in the Y-axis direction of the respective notched portions.