Denso Corporation

Tetsuya Sakakibara

Tatsuo Ozaki

Kazuhiro Mitsukawa

Yoshitaka Kuroda

Toshihide Ninagawa

Mitsuyoshi Saito

Noriyuki Miyazaki

U Ou

Norio Yoshida

Takahide Oohara

A heat exchanger has a flat tube () having a curved portion (). A part of the curved portion () is formed by overlapping an outer rim () on an inner rim (). The inner rim () has a small curvature region (). The small curvature region () is inclined to a flat plate portion (), and is defined by a radius larger than a difference between a half of a thickness of the flat tube () and a thickness of the outer rim (). The small curvature region () is not beyond a center line (C) in a thickness of the flat tube (). The outer rim () extends beyond the center line (C). The outer rim () has an end face () placed on the small curvature region (). The flat tube () has flared portions () expanded at insertion holes ().

Heat exchanger

Each of specific rollers which corresponds to one of the grooves is disposed in a circumference of the metal pipe at equal intervals and is pressed against the periphery of the metal pipe 10, thereby forming a plurality of the grooves at the same time. Because each of the grooves is formed by a specific forming roller, a plurality of the grooves can be formed separately, and the material of the wall between the grooves is prevented from being drawn. Thus, the grooves can be formed into a desired shape.

Method of forming grooves on metal pipe and groove-forming apparatus

Growing community of inventors

Toyohashi, Japan

Tetsuya Sakakibara