FLAT HEAT-EXCHANGING TUBE, HEAT MEDIUM HEATING DEVICE USING SAME, AND VEHICULAR AIR-CONDITIONING DEVICE

摘要

Provided are a flat heat-exchanging tube that can improve heat transmissibility by reducing thermal contact resistance, a heat medium heating device, and a vehicular air-conditioning device. This flat heat-exchanging tube comprises: a flat tube (22) constituted by a pair of molded plates (22A, 22B); and a wavy inner fin (23A, 23B) inserted between the molded plates (22A, 22B), the wavy inner fin having a top part (23C) protruding toward one side and a top part (23D) protruding toward the other side that are brazed to respective inner surfaces of the pair of molded plates (22A, 22B). The wavy inner fin (23A, 23B) includes a tube-expansion permitting part (23E) that permits a wall surface between both top parts (23C, 23D) to deform in a direction in which the distance between the top parts (23C, 23D) expands. The flat heat-exchanging tube (14) is allowed to expand by means of the tube-expansion permitting part (23E) in a state where the top parts (23C, 23D) are brazed between the pair of molded plates (22A, 22B).