Nippondenso Co., Ltd.

Denso Corporation

Yuji Ogawa

Yasuo Abe

Yoshitaka Kuroda

Hisashi Kobayashi

Tamotsu Inoue

Yosimitu Yamaguchi

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

An inner fin, which is formed of a thin plate of an aluminum alloy having a corrugated section in a widthwise direction, includes a plurality of crest surfaces extending parallel in a lengthwise direction, and a plurality of trough surfaces extending parallel in the lengthwise direction. The crest surfaces and the trough surfaces are connected together by inclined surfaces. The crest surfaces are provided with concavities, which are shifted form each other in the lengthwise direction so that the concavities formed in the adjacent crest surfaces are not aligned on the same line in the widthwise direction. The inner fin inserted into the tube partitions the passages which communicate with each other through the concavities.

Inner fin and manufacturing method of the same

In a heat exchanger, an inner fin is formed from a thin plate of aluminum alloy having a corrugated cross-section in a widthwise direction. The inner fin includes multiple crest surfaces extending parallel to one another in a lengthwise direction and multiple trough surfaces extending parallel to one another in the lengthwise direction. The crest surfaces and the trough surfaces are connected together by inclined surfaces. The crest surfaces have concavities which are shifted relative to one other in the lengthwise direction of the fin so that the concavities formed in adjacent crest surfaces are not aligned with one another in the widthwise direction. The inner fin inserted into the tube partitions the passages which communicate with each other through the concavities.

Apparatus and method for forming a heat exchanger inner fin having

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.

Growing community of inventors

Handa, Japan

Yuji Ogawa