Denso Corporation

Nippondenso Co., Ltd.

Yasuo Abe

Yuji Ogawa

Hisashi Kobayashi

Yoshitaka Kuroda

Tamotsu Inoue

Toshihide Takeuchi

Yosimitu Yamaguchi

A metallic corrugated plate applying to a cooling inner fin of a heat exchanger, wherein a bending angle .THETA. of an end bent ridge portion is smaller than bending angle .theta. of the other bent ridge portions. Thus, in case the bending angle .THETA. becomes large by a resilient force after forming the bent ridge portions, preventing a bending rigidity of the end bent ridge portion in the spreading direction from being reduced is possible. Accordingly, preventing the inner fin from being warped from substantially the center ridge of the bent ridge portion is attained.

Method of manufacturing a corrugated plate by rolling for use as an

A cutting device cuts a flat tube in such a manner that a locus connecting each point where a blade tip of a blade portion of the cutting device is firstly introduced into the flat tube passes through a base portion of a frontmost side protrusion portion. Therefore, the bending moment generated due to a cutting force of the cutting device is decreased to prevent defective cutting.

Method for cutting tube

According to the present invention, a roll forming method includes a first roll forming process for forming a trapezoidal projecting portion at a center portion, a second roll forming process for gradually narrowing an upper side of the trapezoidal projecting portion to form a turnup projecting portion, a third roll forming process for forming perpendicularly folded portions at both sides, and a fourth roll forming process for folding a middle portion between the perpendicularly folded portion and the turnup projecting portion in a semi-circular shape. In this way, it is possible to form a turnup projecting portion, insides of which are closely contacted to each other with a curvature which is larger than the conventional curvature, with high speed.

Roll forming method for forming flat tube and roll forming apparatus

The strip 2 is inserted between forming rollers 1a and 1b so that fins 3 are formed on the strip 2. The forming rollers 1a 1b have a line of protrusion protruding radially on the periphery thereof and the protrusion of one roller mates with protrusion of the other roller. A pair of forming rollers or more pairs of forming rollers are employed. A part of the strip 2 sandwiched between side face portions 13a and 14a of the protrusion 13 and 14 is pressed in the direction of the thickness of the strip with a stress between yield stress and maximum stress of the strip 2. To adjust the stress, a clearance G between protrusions is controlled.

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Kariya, Japan

Yasuo Abe