JP2014001902A - Tuber for heat exchanger - Google Patents

Abstract

PROBLEM TO BE SOLVED: To improve brazing between a tube and a header tank by preventing a side surface from becoming uneven when reducing an end portion of the tube, and to suppress generation of a defective article by preventing the header tank from being deformed when inserting the tube.SOLUTION: A tube 10 is a flat tube including a cross section which is long in a flowing direction of outside air. In an end portion of the tube 10 in a length direction, a reduced part 15 is provided which is formed in such a manner that a dimension of the cross section in a long axis direction becomes shorter than a dimension of a cross section of a length-direction intermediate part in the long axis direction. A sectional shape of the reduced part 15 of the tube 10 is a rectangle which is long in a flowing direction of outside air.

Description

  The present invention relates to a heat exchanger tube used as a heat transfer tube provided in a heat exchanger of an air conditioner, for example.

  Conventionally, as this type of heat exchanger tube, a flat tube having a long cross-sectional shape in the flow direction of external air is known. The end portion of the tube is brazed to the peripheral portion of the tube insertion hole while being inserted into the tube insertion hole formed in the header tank, and communicates with the inside of the header tank (see, for example, Patent Document 1).

  In the longitudinal end portion of the tube of Patent Document 1, a narrowed portion is formed in which the major axis dimension of the cross section is set shorter than the major axis dimension of the middle portion in the longitudinal direction of the tube. When forming the constricted portion, a movable mold is used, and a pressure is applied to the end portion of the tube from the outside in the long axis direction of the cross section, so that the end portion of the tube is crushed and plastically deformed. I am doing so. The end of the tube is contracted due to the formation of the throttle portion, and a step is formed on the outer surface of the tube. When the end of this tube is inserted into the tube insertion hole of the header tank, the contracted portion is inserted into the tube insertion hole of the header tank and the step on the outer surface hits the peripheral edge of the tube insertion hole. Positioning in the insertion direction is performed.

JP 2004-233014 A

  However, when the tube is crushed by applying pressure to the end of the tube in the major axis direction of the cross section as described above, the side surface extending in the major axis direction of the cross section is the major axis direction of the outer surface of the tube. As a result of being compressed, a part of the side surface of the tube may be recessed toward the inside of the tube or may protrude toward the outside of the tube.

  If a part of the side of the tube is recessed and a recess is formed, a gap may be formed between the peripheral edge of the tube insertion hole of the header tank and the side of the tube, resulting in poor brazing between the tube and the header tank. There is. In addition, if a part of the side surface of the tube protrudes outward to form a convex part, the convex part is caught by the peripheral part of the tube insertion hole when the end of the tube is inserted into the tube insertion hole. There is a risk of deforming the peripheral edge of the tube insertion hole.

  The present invention has been made in view of such a point, and the object of the present invention is to prevent a tube from being recessed or protruded on the side surface of the tube when the tube end is contracted. In addition to improving the brazing with the header tank, the header tank is not deformed when the tube is inserted, thereby suppressing the occurrence of defective products.

  In order to achieve the above object, in the present invention, the cross-sectional shape of the tube contraction portion is a rectangle that is long in the flow direction of the external air.

A first invention is for a heat exchanger configured to be inserted into a tube insertion hole formed in a header tank through which a heat exchange medium flows and connected to the header tank so as to exchange heat between the heat exchange medium and external air. In the tube
The tube is a flat tube having a long cross section in the flow direction of external air,
At the end portion in the longitudinal direction of the tube, a contracted tube portion formed so that the dimension in the major axis direction of the cross section is shorter than the dimension in the major axis direction of the cross section in the longitudinal middle portion of the tube is provided.
The cross-sectional shape of the reduced tube portion of the tube is a rectangle that is long in the flow direction of the external air.

  That is, for example, when a tube is formed by pressing the end of the tube in the longitudinal direction of the cross section using a mold, the end of the tube is plastic so that the cross-sectional shape of the tube is rectangular. When deformed, the material making up the tube escapes toward the corner of the mold so that it forms a rectangular corner. In other words, since there is a material escape area when the tube is contracted, the compressive force on the side surface extending in the major axis direction of the cross section on the outer surface of the tube is reduced. Thereby, it becomes possible to suppress the formation of a recess or a protrusion on the side surface of the tube.

According to a second invention, in the first invention,
The tube has a first contracted tube portion formed so that the dimension in the major axis direction of the cross section is shorter than the dimension in the major axis direction of the cross section of the middle portion in the longitudinal direction of the tube; A second contraction tube portion formed so that the dimension is shorter than the dimension in the major axis direction of the cross section of the first contraction tube portion is provided continuously in the longitudinal direction of the tube;
The second contraction tube portion is positioned at an end portion of the tube and has a cross-sectional shape that is a rectangle that is long in the flow direction of the external air.

  According to the first invention, since the cross section of the tube contraction portion of the tube is a rectangle that is long in the flow direction of the external air, the material constituting the tube is formed into a rectangular corner when forming the tube contraction portion. I can escape. Thereby, since the compressive force which acts on the side surface of a tube can be reduced, it can suppress that a recessed part and a convex part are formed in a side surface. As a result, the tube and the header tank can be brazed well, and the header tank can be prevented from being deformed when the tube is inserted, thereby suppressing the occurrence of defective products.

  According to the second invention, when the first and second contracted tube portions are provided in the tube, the second contracted tube portion is positioned at the end of the tube, and the cross-sectional shape thereof is a rectangle that is long in the flow direction of the external air. Therefore, it is possible to improve the brazing between the tube and the header tank, and it is possible to suppress the occurrence of defective products by preventing the header tank from being deformed when the tube is inserted.

It is a front view of the heat exchanger concerning an embodiment. It is a one part perspective view of a heat exchanger. It is a disassembled perspective view of a part of heat exchanger. It is a perspective view of a tube. It is a top view of a tube. It is an end view of a tube. It is a figure explaining the point which shape | molds an intermediate molded product with a shaping | molding apparatus. It is a figure which shows the state which shape | molded the reduced tube part with the shaping | molding apparatus. FIG. 6 is a diagram corresponding to FIG. 4 according to a modification.

  Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings. It should be noted that the following description of the preferred embodiment is merely illustrative in nature, and is not intended to limit the present invention, its application, or its use.

  Drawing 1 is a figure which looked at heat exchanger 1 provided with tube 10 concerning the embodiment of the present invention from the flow direction of external air. The heat exchanger 1 constitutes a part of an air conditioner (not shown) mounted on a vehicle such as an automobile, and can be used as, for example, a refrigerant condenser, a refrigerant evaporator, or the like.

  The heat exchanger 1 includes a core 2 and a pair of left and right header tanks 3 and 4. The core 2 has a plurality of fins 5 and tubes 10 extending in the left-right direction. The fins 5 and the tubes 10 are alternately arranged in the vertical direction. End plates 6 and 6 for protecting the core 2 are provided at the upper end and the lower end of the core 2, respectively. The end plates 6 and 6 are made of an aluminum alloy.

  The left header tank 3 includes a cylindrical portion 3a extending in the vertical direction and caps 3b and 3b for closing the openings at the upper and lower ends of the cylindrical portion 3a, which are made of an aluminum alloy. The caps 3b and 3b are brazed to the cylindrical portion 3a.

  A refrigerant inflow pipe A is provided at the upper portion of the cylindrical portion 3a so as to communicate with the inside of the cylindrical portion 3a. The refrigerant inflow pipe A is for allowing a refrigerant (heat exchange medium) to flow into the left header tank 3 from the outside of the heat exchanger 1, and is connected to other devices that constitute a refrigeration cycle apparatus (not shown). .

  As shown in FIGS. 2 and 3, a plurality of tube insertion holes 3 c for inserting the tubes 10 are formed in the cylindrical portion 3 a at intervals in the vertical direction corresponding to the arrangement intervals of the tubes 10. . The tube insertion hole 3c is opened in a slit shape that is long in the circumferential direction of the cylindrical portion 3a. The upper edge and the lower edge of the tube insertion hole 3c extend along the circumferential direction of the cylindrical portion 3a. On the other hand, both side edges of the tube insertion hole 3c are curved toward the outside of the tube insertion hole 3c.

  Similarly to the left header tank 3, the right header tank 4 includes a cylindrical portion 4a and caps 4b and 4b. A refrigerant outflow pipe B is provided at the lower portion of the cylindrical portion 4a so as to communicate with the inside of the cylindrical portion 4a. The refrigerant outflow pipe B is for flowing out the refrigerant inside the heat exchanger 1 to the outside, and is connected to other equipment constituting the refrigeration cycle apparatus.

  The fin 5 is a corrugated fin formed in a wave shape continuous in the left-right direction when viewed from the air flow direction, and is made of an aluminum alloy.

  The tube 10 is a flat tube having a long cross section in the flow direction of external air, and is formed by extrusion molding of an aluminum alloy. As shown in FIGS. 4 to 6, of the outer surface of the tube 10, the upper and lower side surfaces extending in the major axis direction of the cross section are parallel to each other along the flow direction of the external air, and the left-right direction of the heat exchanger 1. It is comprised by the flat surfaces 11 and 11 extended to. The flat surfaces 11, 11 are arranged along the upper and lower edges of the tube insertion hole 3c. The fins 5 are brazed to the flat surfaces 11 and 11.

  Of the outer surface of the tube 10, the front and rear surfaces extending in the minor axis direction of the cross section are configured by curved surfaces 12 and 12 that are curved in an arc shape so that the center portion in the vertical direction is located most outside the tube 10. The curved surfaces 12, 12 are arranged along the curved side edge of the tube insertion hole 3c.

  In the tube 10, a plurality of refrigerant channels 13, 13,... Extending in the longitudinal direction are formed so as to penetrate the tube 10. Between the adjacent refrigerant flow paths 13, 13, a plurality of middle pillar portions 14, 14,... Extending so as to connect the upper flat surface 11 and the lower flat surface 11 of the tube 10 are provided. Refrigerant flow paths 13 and 13 located on both sides in the major axis direction of the cross section of tube 10 are curved surfaces. On the other hand, the other refrigerant flow paths 13, 13,... Located on the inner side in the long axis direction of the cross section of the tube 10 have a substantially rectangular cross section.

  At both end portions of the tube 10 in the longitudinal direction, the contracted tube portions 15 are provided. The contracted tube portion 15 is a portion formed such that the dimension in the major axis direction of the cross section is shorter than the dimension in the major axis direction of the cross section of the middle portion in the longitudinal direction of the tube 10. The dimension in the minor axis direction of the cross section of the contracted tube portion 15 is the same as the dimension in the minor axis direction of the section of the middle portion in the longitudinal direction of the tube 10.

  The cross-sectional shape of the contracted tube portion 15 is a rectangle that is long in the flow direction of the external air, that is, a rectangle. Therefore, the upper and lower side surfaces extending in the major axis direction of the cross section of the outer surface of the contracted tube portion 15 are constituted by flat surfaces 15a and 15a extending in parallel with each other along the flow direction of the external air. On the other hand, the front and rear surfaces extending in the short axis direction of the cross section of the outer surface of the contracted tube portion 15 are constituted by flat surfaces 15b and 15b extending in the vertical direction. Since the cross-sectional shape of the contracted tube portion 15 is rectangular, four approximately perpendicular corners are formed in the contracted tube portion 15.

  By forming the contracted tube portion 15 at the end of the tube 10, step portions 17, 17 are formed in the tube 10. The size of the stepped portions 17, 17 is the difference between the separation size of the flat surfaces 15 b, 15 b of the contracted tube portion 15 and the separation size of the curved surfaces 12, 12 at the intermediate portion in the longitudinal direction of the tube 10.

  The left side of the tube 10 is inserted into the tube insertion hole 3 c of the left header tank 3. As shown in FIG. 2, the insertion amount of the tube 10 is set so that the contracted tube portion 15 is located inside the header tank 3 with respect to the tube insertion hole 3c, and the step portions 17 and 17 are formed in the tube insertion hole 3c. It is located inside the header tank 3 without engaging the peripheral edge. The left flat surfaces 11 and 11 and the curved surfaces 12 and 12 of the tube 10 are brazed to the peripheral edge portion of the tube insertion hole 3 c of the header tank 3. Thereby, the tube 10 and the header tank 3 are connected. Note that the right side of the tube 10 is also inserted into the tube insertion hole 4c of the right header tank 4 and brazed to the peripheral edge portion in the same manner as the left side.

  Next, the manufacturing method of the heat exchanger 1 comprised as mentioned above is demonstrated. The left and right header tanks 3 and 4 are molded, and the end plates 6 and 6, the fins 5 and the tubes 10 are molded. The header tanks 3 and 4 and the fins 5 are formed of a clad material clad with a brazing material.

  The tube 10 is formed as follows. First, an aluminum alloy is extruded to obtain a long member. Thereafter, the long member is cut into the same length as the tube 10 to obtain an intermediate molded product 20 as shown in FIG.

  Next, the reduced tube portion 15 is formed in the intermediate molded product 20. When forming the contracted tube portion 15, the forming apparatus 100 is used. The molding apparatus 100 includes a first mold 101 and a second mold 102. The molding surface 101a of the first mold 101 is for molding one side in the long axis direction of the contracted tube portion 15, and is formed in a U shape. On the other hand, the molding surface 102a of the second mold 102 is for molding the other side in the major axis direction of the contracted tube portion 15 and is opened to the opposite side to the molding surface 101a of the first mold 101. It is formed in a shape.

  After the intermediate molded product 20 is disposed between the first mold 101 and the second mold 102, the first mold 101 and the second mold 102 are brought close to each other as shown in FIG. The moving direction of the first mold 101 and the second mold 102 is the long axis direction of the cross section of the intermediate molded product 20 (the same direction as the long axis direction of the cross section of the tube 10).

  When the molding surface 101a and the molding surface 102a come into contact with the end of the intermediate molded product 20 in the longitudinal direction, a compressive force acts on the end of the intermediate molded product 20 in the longitudinal direction of the cross section. As a result, the end of the intermediate molded product 20 is contracted, and the cross section is molded into a rectangle. In the middle of this molding, the material constituting the end of the intermediate molded product 20 is directed toward the corners of the molding surfaces 101a and 102a of the first mold 101 and the second mold 102 so that the corners of the rectangle are formed. I will escape. That is, the corners of the molding surfaces 101a and 102a serve as escape places for the material, and the presence of this escape place reduces the compressive force on the flat faces 11 and 11 extending in the major axis direction of the cross section on the outer surface of the tube 10. As a result, it is possible to prevent the recesses and the projections from being formed by suppressing the deformation of the flat surfaces 11 and 11 of the tube 10.

  The tubes 10 and the fins 5 obtained as described above are alternately arranged to form the core 2, and the end plates 6 and 6 are disposed at the outer end of the core 2.

  Thereafter, both ends of each tube 10 are inserted into the tube insertion holes 3c and 4c of the left and right header tanks 3 and 4, respectively. At this time, the contracted tube portion 15 of the tube 10 is inserted into the header tanks 3 and 4 from the tube insertion holes 3c and 4c. Since the convex portions are not formed on the flat surfaces 11 and 11 of the tube 10 when the tube 10 is inserted, the tube 10 can be inserted smoothly and the deformation of the header tanks 3 and 4 can be prevented.

  After the core 2 and the header tanks 3 and 4 are integrated, the core 2 and the header tanks 3 and 4 are transported into a brazing furnace and heated to melt the brazing material of each part and reach the brazed portion. At this time, since the concave portions are not formed on the flat surfaces 11 of the tube 10, it is possible to reliably braze the outer surface of the tube 10 and the peripheral edge of the tube insertion hole 3c over the entire circumference. .

  As described above, according to this embodiment, since the cross section of the contracted tube portion 15 of the tube 10 has a rectangular shape that is long in the flow direction of the external air, the material constituting the tube 10 when the contracted tube portion 15 is formed. Can be escaped to form the corners of a rectangle. Thereby, since the compressive force which acts on the flat surfaces 11 and 11 of the tube 10 can be reduced, it can suppress that a recessed part and a convex part are formed in the flat surfaces 11 and 11. FIG. As a result, the tube 10 and the header tanks 3 and 4 can be brazed well, and the header tanks 3 and 4 can be prevented from being deformed when the tube 10 is inserted, thereby suppressing the occurrence of defective products.

  Further, as in the modification shown in FIG. 9, the tube 10 is formed so that the dimension in the major axis direction of the cross section is shorter than the dimension in the major axis direction of the cross section of the middle part in the longitudinal direction of the tube 10. The tube 10 includes a first contraction tube portion 30 and a second contraction tube portion 31 formed so that the dimension in the major axis direction of the cross section is shorter than the dimension in the major axis direction of the cross section of the first contraction tube portion 30. It may be provided continuously in the longitudinal direction. The amount of contraction of the first contracted tube portion 30 is set to be small enough to prevent the flat surface 11 of the tube 10 from having a convex portion or a concave portion.

  The second contracted tube portion 31 constitutes the contracted tube portion of the present invention, and is positioned at the end of the tube 10 and has a rectangular cross-sectional shape that is long in the flow direction of the external air, like the contracted tube portion 15. It is said that. Therefore, the upper and lower side surfaces extending in the major axis direction of the cross section of the outer surface of the second contracted tube portion 31 are constituted by flat surfaces 31a and 31a extending in parallel with each other along the flow direction of the external air. Further, of the outer surface of the second contracted tube portion 31, both front and rear surfaces extending in the minor axis direction of the cross section are configured by flat surfaces 31b and 31b extending in the vertical direction.

  Furthermore, in the tube 10 of the modified example, first step portions 32 and 32 are formed between the first contracted tube portion 30 and the longitudinal intermediate portion of the tube 10, and the first contracted tube portion 30 and the second contracted tube are formed. Second step portions 33, 33 are formed between the portion 31.

  The insertion amount of the tube 10 is such that the second contracted tube portion 31 is positioned inside the header tank 3 with respect to the tube insertion hole 3c of the header tank 3, and the first step portions 32 and 32 are the peripheral edges of the tube insertion hole 3c. It is set so as to come into contact with the portion from the outside of the header tank 3. Accordingly, the outer surface of the first contracted tube portion 30 is brazed to the peripheral edge portion of the tube insertion hole 3c. Also in this modified example, the material constituting the tube 10 can be released so as to form a rectangular corner when the second contracted tube portion 31 is formed.

  Therefore, when the first and second contracted tube portions 30 and 31 are provided in the tube 10, the second contracted tube portion 31 is positioned at the end of the tube 10 and the cross-sectional shape is a rectangle that is long in the flow direction of the external air. The tube 10 and the header tanks 3 and 4 can be brazed well, and the header tanks 3 and 4 can be prevented from being deformed when the tube 10 is inserted, thereby suppressing the occurrence of defective products.

  In addition, although the said embodiment demonstrated the case where the tube 10 concerning this invention was used as a heat exchanger tube of the heat exchanger of a vehicle air conditioner, not only this but using as a heat exchanger tube of various heat exchangers. it can.

  In addition, the method for forming the contracted tube portions 15, 30, and 31 of the tube 10 is not limited to the above-described method, and any method may be used as long as a processing force is applied in the major axis direction of the cross section.

  As described above, the heat exchanger tube according to the present invention can be used as, for example, a heat transfer tube of a vehicle air conditioner.

DESCRIPTION OF SYMBOLS 1 Heat exchanger 2 Core 3, 4 Header tank 3c, 4c Tube insertion hole 10 Tube 15 Contraction part 17 Step part 30 1st contraction part 31 2nd contraction part

Claims (2)

In a heat exchanger tube configured to be inserted into a tube insertion hole formed in a header tank through which a heat exchange medium flows and connected to the header tank, and to exchange heat between the heat exchange medium and external air,
The tube is a flat tube having a long cross section in the flow direction of external air,
At the end portion in the longitudinal direction of the tube, a contracted tube portion formed so that the dimension in the major axis direction of the cross section is shorter than the dimension in the major axis direction of the cross section in the longitudinal middle portion of the tube is provided.
The tube for a heat exchanger, wherein a cross-sectional shape of a contraction tube portion of the tube is a rectangle that is long in a flow direction of external air. In the heat exchanger tube according to claim 1,
The tube has a first contracted tube portion formed so that the dimension in the major axis direction of the cross section is shorter than the dimension in the major axis direction of the cross section of the middle portion in the longitudinal direction of the tube; A second contraction tube portion formed so that the dimension is shorter than the dimension in the major axis direction of the cross section of the first contraction tube portion is provided continuously in the longitudinal direction of the tube;
The second contraction tube portion is positioned at an end portion of the tube and has a cross-sectional shape of a rectangle that is long in the flow direction of the external air.

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