Patent ID: 7726024

Claim:
A method for manufacturing a heat exchanger, the method comprising: inserting a tube in which a fluid flows into a plurality of plate fins each shaped like a flat plate; expanding the tube to mechanically connect the tube to the plate fins to form a core portion; and forming a tube hole portion in a header plate forming a part of a header tank, wherein the tube hole portion includes a first chamfered portion and a second chamfered portion; connecting an end portion of the tube in a longitudinal direction of the tube to the header plate so as to form an abutting portion, wherein the forming of the abutting portion includes: inserting the end portion of the tube into the tube hole portion, from a side of the first chamfered portion to a side of the second chamfered portion, bending an entire periphery of the inserted end portion of the tube to a flat surface of the header plate to form a flange portion, and abutting the flange portion to the flat surface of the header plate so as to form the abutting portion; and applying a predetermined load in a direction in which the flange portion abuts the header plate while vibrating the tube by supersonic vibration in a direction in which a surface of the abutting portion extends, wherein in the applying step, the tube is solid-boned to the header plate in a solid phase by deforming the tube and the header plate, such that a peak portion between the flat surface of the header plate and the second chamfered portion is crushed, and a material of the header plate near the tube hole portion flows to a space between the first chamfered portion and the tube.