Hidaka Seiki Kabushiki Kaisha

Dai Nippon Printing Co., Ltd.

Yoshihiro Baba

Chikao Ikenaga

Daigo Aoki

Hideyuki Okamoto

Toshiki Miyazawa

Kensaku Honma

A standard mask apparatus includes at least one standard mask including at least one through-hole. The standard mask apparatus may include standard regions each including the at least one through-hole. The standard regions may be arranged in a first direction and in a second direction that intersects with the first direction. A ratio of a dimension of each standard region in the first direction to a dimension of an interval between two of the standard regions in the first direction may be higher than or equal to 0.1. A ratio of a dimension of each standard region in the second direction to a dimension of an interval between the two standard regions in the second direction may be higher than or equal to 0.1.

Standard mask apparatus and method of manufacturing standard mask apparatus

The present invention solves a problem with conventional tube expanding method for heat exchanger tubes that is susceptible, when carrying out tube expansion on U-shaped heat exchanger tubes that have a narrower diameter than in the past and forming flare portions in opening portions that have been subjected to tube expansion, to a buckling phenomenon at boundaries between straight portions and hairpin portions of the heat exchanger tubes or a vicinity thereof. Opening portions of U-shaped heat exchanger tubesthat pass through a fin layerprotrude from an upper end surface of the fin layer, hairpin portionsof the heat exchanger tubesprotrude from a lower end surface of the fin layer, and tube expanding billetsare inserted into each opening portion of the heat exchanger tubesto carry out primary tube expansion that expands the diameter of each straight tube portionof the heat exchanger tubesto integrate the heat exchanger tubesand fins. The primary tube expansion ends with each tube expanding billetinserted into a boundary between the straight tube portionand the hairpin portionof a heat exchanger tubeor the vicinity thereof. The tube expanding billetsare then held at the positions where the primary tube expansion ended and flare punchesare inserted into the opening portions of the heat exchanger tubesthat have been subjected to the primary tube expansion to form flare portionsin front end portions of the heat exchanger tubes

Tube expanding method for heat exchanger tubes and tube expanding apparatus for heat exchanger tubes

In a state where the expanded protruding portion of the heat-exchanging tube, which has been expanded inside a grip portion of a chucking sleeve whose diameter has been reduced by a clamp bushing, is gripped by the grip portion, a tube expanding billet is inserted into a yet-unexpanded part of the heat-exchanging tube to cause tube expansion. When doing so, a guide portion, which is formed on a flare punch and has the same diameter as the maximum outer diameter of the tube expanding billet, is inserted inside the expanded protruding portion of the heat-exchanging tube gripped by the grip portion.

Tube expanding apparatus

In the method of manufacturing a heat exchanger, transverse sectional shapes of heat exchanging tubes can be easily formed into elliptical shapes. The method includes the steps of: piling metallic fins, each of which includes collared through-holes, so as to form tube holes, which are formed by connecting the collared through-holes; piercing heat exchanging tubes, whose transverse sectional shapes are circular shapes, through the tube holes; and inserting expanding bullets, whose transverse sectional shapes are elliptical shapes, into the heat exchanging tubes. The heat exchanging tubes are elliptically expanded to and integrated with the metallic fins.

Method of manufacturing heat exchanger

A tube expanding bullet is inserted into and expands a heat exchanger tube which has been pierced through collared fin holes of piled heat exchanging fins, so as to expand the fin holes and integrate the tube with the heat exchanging fins. The tube expanding bullet has a first part formed at a front part of the tube expanding bullet and a second part formed at a rear part of the tube expanding bullet whose maximum outer diameter is greater than that of the first part. The fin holes are firstly expanded by passing the first part of the bullet through the tube. The fin hole is secondly expanded by passing the second part of the bullet through the tube. A first rate of expansion of the fin hole by the first part of the tube expanding bullet is less than a second rate of expansion of the fin hole by the second part of the bullet.

Tube expanding bullet and method of expanding tube

In forming a heat exchanger, a tube of the heat exchanger is expanded by a bullet, which is attached to a mandrel. The tube is projected from both end faces of a piled body formed by piling a plurality of fins. Each fin has a tube hole through which the tube passes. The fins and the tube are integrated by expansion of the tube. A first projected section of the tube, which is projected from one end face of the piled body and which has been expanded by the bullet, is held at a prescribed position. The bullet is pressed toward a second projected section, which is projected from the other end face of the piled body. As the bullet moves toward the second projected section, it expands the tube. The second projected section of the tube is allowed to contract during the tube expansion. An object of the present invention is to prevent adhesion of adjacent fins and irregularities in fin clearances between adjacent fins.

Growing community of inventors

Tokyo, Japan

Yoshihiro Baba