JP2006064212A - Header pipe for heat exchanger, and its manufacturing method - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide header pipes for a heat exchanger with superior pressure resistance strength with no cracks or notches by eliminating bias of a clad layer, particularly bias to corner parts, and uniforming a thickness of the header pipe. <P>SOLUTION: In the heat exchanger comprised by integrally fixing by brazing a pair of the header pipes 2a and 2b respectively formed by aluminum members, a plurality of heat exchange tubes 3 extended between the header pipes in parallel with each other, and fins 4 interposed between the heat exchange tubes, the header pipe is formed like a square tube by carrying out reduction working of a cylindrical electric resistance welded pipe clad with brazing material 1 in at least one face of an inner face or an outer face. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  TECHNICAL FIELD The present invention relates to a header pipe for a heat exchanger and a method for manufacturing the same, and more particularly to an aluminum heat exchanger header pipe arranged on the left and right or top and bottom and through which a heat medium flows, and a method for manufacturing the same. It is. Here, aluminum is meant to include aluminum or an aluminum alloy.

  Conventionally, this type of heat exchanger has a pair of substantially cylindrical header pipes each made of aluminum, a plurality of parallel heat exchange tubes installed between the header pipes, and between adjacent heat exchange tubes. In general, a structure in which a fin interposed between the two is integrally brazed is known.

  By the way, in a heat exchanger in which the width is limited in the place where it is arranged, the front area effective for heat exchange is reduced by the width corresponding to the diameter of the header pipe. The width here means the vertical width when the header pipe is arranged vertically, and the horizontal width when the header pipe is arranged left and right.

  Therefore, a square tubular header pipe is used instead of the cylindrical header pipe. As a method for producing this square tubular header pipe, a method is known in which a brazing filler metal layer is formed on a square tubular header pipe formed of an aluminum extruded profile (see, for example, Patent Document 1).

In addition, as another rectangular tubular header pipe, a press-molded plate made of a brazing sheet clad with a brazing material is subjected to a pressing process such as bending, and a base wall having a tube insertion hole and an opposing wall are provided. A method of producing a header pipe such as a rectangle by brazing is known (in particular, see Patent Document 2).
JP 2002-277187 (Claims, 0011, FIG. 2, FIG. 3, FIG. 4) JP 2002-357395 (Claims, 0003, 0087, FIG. 1, FIG. 5, FIG. 6)

  However, in the former technique, that is, the technique described in JP-A-2002-277187, a brazing filler metal layer is formed on the extruded rectangular tubular header pipe, so that there is a problem that the manufacturing process increases and is complicated.

  On the other hand, in the latter technique, that is, the technique described in JP-A-2002-357395, high-precision bending and pressing are required, and it takes a lot of man-hours and labor to produce a header pipe. This is necessary, especially when a long header pipe is manufactured, a large mold is required. In addition, since the joining portion by brazing is long, when a brazing failure occurs, a serious quality problem that it does not function as a heat exchanger occurs due to leakage of the internal heat medium. Furthermore, an overlap margin for the brazing portion is necessary, and extra material for forming the tube is required, which increases the weight.

  As a method of solving this problem, a cylindrical electric sewing tube is produced by a clad extruded tube or a brazing sheet directly extruded into a rectangular cylindrical shape, and the electric sewing tube is formed into a rectangular tube shape by pressing. Etc. are considered. However, in a clad extrusion tube extruded directly into a rectangular tube shape, the thickness of the clad layer is likely to be biased, and in particular, such a bias is caused that the cladding layer of the corner portion is thickened. At the corner where the cladding layer becomes thick in this way, the cladding layer (brazing material) melts in the brazing process, so the tube thickness may decrease after brazing, and the quality of the heat exchanger such as pressure resistance There is a problem of adversely affecting. In addition, in the method of forming a cylindrical ERW tube into a square cylinder by pressing, an excessive load is applied to the corner by press molding, so that the outer surface is easily cracked and the inner surface is notched. There is a possibility that (notches and dents) may occur, and this also has a problem of adversely affecting the quality of the heat exchanger such as pressure resistance. Furthermore, in order to perform press molding, many man-hours and labor are required, and a mold for bending and pressing is necessary. In particular, when a long header pipe is manufactured, a large mold is necessary.

  The present invention has been made in view of the above circumstances, eliminates the bias of the clad layer, particularly the corner portion, makes the header pipe uniform in thickness, and excels in heat and pressure resistance without cracks and notches. It is an object of the present invention to provide a dexterous header pipe and a manufacturing method thereof.

  In order to solve the above-described problems, a header pipe for a heat exchanger according to the present invention includes a pair of header pipes each formed of an aluminum member, and a plurality of heat exchange tubes that are laid in parallel between the header pipes. And a fin interposed between the heat exchange tubes, in a heat exchanger that is integrally fixed by brazing, a header pipe is connected to a cylindrical electric electrode having a brazing material clad on at least one of the inner surface and the outer surface. The sewing tube is formed into a square tube shape by drawing (Claim 1).

  A method of manufacturing a header pipe for a heat exchanger according to the present invention is a method of manufacturing the header pipe, wherein a brazing sheet having a brazing material clad on at least one of the front and back surfaces is subjected to electro-sewing processing to form a cylindrical tube. And a step of forming a rectangular pipe for a header pipe by drawing the cylindrical pipe (claim 2).

  In the method of manufacturing a header pipe for a heat exchanger according to claim 2, the drawing process may be performed at least once, but may be performed a plurality of times to form a rectangular pipe for a header pipe having a predetermined thickness. (Claim 3)

  (1) According to the first aspect of the present invention, since the cylindrical ERW pipe having the brazing material clad on at least one of the inner surface and the outer surface is formed into a rectangular tube shape by drawing, the clad layer is a corner portion. This makes it possible to provide a header pipe for a heat exchanger that is uniform in the thickness of the header pipe and is excellent in pressure resistance without cracks or notches.

  (2) According to the invention described in claim 2, a cylindrical tube is formed by electro-sewing a brazing sheet clad with brazing material on at least one of the front and back surfaces, and this cylindrical tube is drawn for header pipes by drawing. Since the rectangular tube is formed, it can be processed continuously. In addition, a cylindrical ERW tube can be formed into a rectangular cylindrical cladding tube by drawing using a die having a square bearing, and it is easy to make a square tube without increasing the size of the mold compared to press molding. Shaped header pipes can be produced.

  (3) According to the invention described in claim 3, since a rectangular tube for a header pipe having a predetermined thickness is formed by drawing a plurality of times, a uniform thickness header pipe with high dimensional accuracy is produced. can do. Therefore, the quality can be further improved in addition to the above (2).

  Below, the best embodiment of the heat exchanger with a liquid receiver according to the present invention will be described in detail.

  FIG. 1: is the perspective view (a) which shows an example of the heat exchanger which concerns on this invention, and the principal part expanded sectional view (b) of the said heat exchanger.

  As shown in FIG. 1, the heat exchanger includes a pair of aluminum header pipes 2a and 2b, and a plurality of heat exchange tubes 3 installed in parallel between the header pipes 2a and 2b. The heat exchange tubes 3 are mainly composed of heat exchange fins such as corrugated fins 4 that are interposed between the heat exchange tubes 3 and joined together.

  The header pipes 2a and 2b are formed as rectangular tubular tubes having a rectangular cross section by drawing a cylindrical electric sewing tube made of aluminum with the brazing material 1 clad on the inner surface and the outer surface. In this case, a cylindrical ERW tube having a diameter of 27.7 mm and a wall thickness of 1.2 mm is subjected to a drawing process to obtain a width x depth of 14.0 mm x 24.5 mm, a wall thickness of 1.0 mm, and an arc portion of a corner portion. The header pipes 2a and 2b having a radius of 1.75 mm are formed. Thus, the cylindrical header pipe having the same thickness and the same flow path cross-sectional area is used by setting the width x depth x thickness of the header pipes 2a and 2b to 14.0 mm x 24.5 mm x 1.0 mm. If the width of the heat exchanger is the same as that of the heat exchanger, the width of the front effective area portion is 13 mm larger, and the front effective area where heat exchange is performed can be increased.

  The header pipes 2a and 2b have a rectangular cross section as long as they are formed into a rectangular tube shape by drawing a cylindrical electric sewn tube made of aluminum with the brazing material 1 clad on at least one of the inner surface and the outer surface. Or any of a square may be sufficient.

  Aluminum end caps 5 are fixed to the upper and lower ends of the header pipes 2a and 2b by brazing. In addition, a high-temperature heat medium inflow pipe (not shown) is provided, for example, near the outer upper end of one header pipe 2a (left side in FIG. 1), and an aluminum inflow pipe 6 is provided in the inflow pipe. Joined by brazing. A heat medium outlet (not shown) is provided near the outer lower end of the other header pipe 2b (right side in FIG. 1), and an aluminum outlet pipe 7 is brazed to the outlet. It is joined by.

  Further, as shown in FIG. 1, the heat exchange tube 3 is formed, for example, in a flat plate shape with an aluminum extruded shape, and is divided into a plurality of holes penetrating in the longitudinal direction. A heat medium passage 3a is formed. Both end portions of the heat exchange tube 3 formed in this way are inserted and fixed in a plurality of insertion holes 2c arranged in parallel with each other on the opposite sides of the header pipes 2a and 2b. Yes.

  As shown in FIG. 1A, the heat exchange fins, that is, the corrugated fins 4 are formed in a continuous wave shape by bending an aluminum plate, and are interposed between the heat exchange tubes 3. It is brazed. In this case, the corrugated fins 4 are brazed and joined to the outer sides of the heat exchange tubes 3 arranged at the uppermost and lowermost stages, and both the corrugated fins 4 are protected in order to protect the corrugated fins 4. Further, a side plate (not shown) is brazed and joined to the outer side.

  Next, a method for manufacturing the header pipes 2a and 2b will be described with reference to the flowcharts shown in FIGS. Here, the case where header pipes 2a and 2b in which the brazing filler metal 1 is clad on the outer surface side will be described.

  First, an aluminum original material (brazing sheet) having a brazing filler metal 1 clad on the outer surface side is prepared (step 4-1). Next, a cylindrical electric sewing tube 10 (hereinafter referred to as a round tube 10) is produced by electro-sewing processing of the brazing sheet (step 4-2). In this case, the round tube 10 has a butted portion of a brazing sheet bent into a cylindrical shape joined by high frequency induction welding. In this case, the round tube 10 is formed to have a diameter: 27.7 mm and a wall thickness: 2.2 mm.

  Next, as shown in FIGS. 2 and 3, the round tube 10 is formed by drawing to form a rectangular tube 20 for a header pipe having a rectangular tube shape (hereinafter referred to as a square tube 20). In this case, first, a primary drawing process is performed, and the size of the square tube 20 is formed to 17 mm × 27.5 mm, for example, and the radius of the arc portion of the corner portion is 1.75 mm (step 4-3). Next, secondary drawing is performed to form the square tube 20 into a predetermined size, for example, 14.0 mm × 24.5 mm, and the radius of the arc portion of the corner portion to 1.75 mm (step 4-4). After the insertion hole 2c (see FIG. 1B) of the heat exchange tube 3 is provided in the produced square tube 20, the pair of square tubes 20 (header pipes 2a, 2b) and heat laminated in parallel to each other The exchange tube 3 and the corrugated fins 4 are assembled and fixed in a jig (not shown), and then loaded into a furnace, heated and brazed to produce a heat exchanger (step 4-5).

  In addition, as shown in FIG.2 and FIG.3, the drawing processing apparatus which performs a drawing process is the cross section square arrange | positioned through the mandrel 32 inside the die | dye 30 which has the bearing 31 of a square hole, and the bearing 31, for example. A plug 33 having a shape, and a carriage 35 having a chuck 34 for gripping the tip end portion of the square tube 20 formed into a square tube shape through a mold hole formed by the bearing 31 and the plug 33. ing. According to the drawing processing apparatus configured in this way, the processing oil is supplied between the die 30 and the tube (round tube 10, square tube 20) and between the plug 33 and the tube (round tube 10, square tube 20). In addition, the square tube 20 can be formed by moving the carriage 35 to the drawing side and drawing the round tube 10. In addition, in FIG. 2, although the apparatus which performs one drawing process was demonstrated, when performing the primary drawing process and the secondary drawing process, it changed from the round tube to the square tube by the primary drawing process, and also became a square shape. Separate the process of making the tube into a highly accurate square tube by secondary drawing, or arrange the die and plug for primary drawing (round → square) and the secondary drawing die and plug in series, A method of performing the primary drawing process and the secondary drawing process at the same time in one drawing can be adopted.

  In the above description, the case where the drawing process is performed in two stages of the primary drawing process and the secondary drawing process has been described. However, if the required dimensional accuracy and appearance are low, the rectangular tube 20 can be manufactured by one drawing process. Good.

  That is, as shown in FIG. 5, first, an aluminum base material (brazing sheet) having a brazing filler metal 1 clad on the outer surface side is prepared (step 5-1). Next, a round tube 10 (cylindrical electric sewing tube) is produced by electro-sewing processing of this brazing sheet (step 5-2). Next, the round tube 10 is manufactured by drawing to form a square tube 20 for a square pipe header pipe having a predetermined dimension, for example, 14.0 mm × 24.5 mm and a radius of the arc portion of the corner portion of 1.75 mm ( Step 5-3). And after providing the insertion hole 2c (refer FIG.1 (b)) of the heat exchange tube 3 in the produced square tube 20, it laminates | stacks in parallel with a pair of square tube 20 (header pipe 2a, 2b). The heat exchange tube 3 and the corrugated fins 4 are assembled and fixed in a jig (not shown), and then loaded into a furnace, heated and brazed to produce a heat exchanger (Step 5- 4).

Next, using BAS171P of JIS-Z3263-2002 shown in Table 1 as a brazing sheet, the square tube 20 (header pipe 2a, header pipe 2a, manufactured by Example 1 shown in FIG. 4 and Example 2 shown in FIG. 5) is used. When an external appearance observation and a cross-sectional observation were performed on the heat exchanger (Example 3) using 2b) and the square tube 20 (header pipes 2a and 2b), the following evaluation results were obtained.

  As a result of the appearance observation, there was no crack or notch in the corner portion in any of Example 1 and Example 2. Further, as a result of cross-sectional observation, it was confirmed that in both Example 1 and Example 2, the clad rate was the same as the clad rate of 10% of the original material on the entire circumference including the corner portion.

  As a result of comparing the performance of a heat exchanger having a height of 150 mm and a width of 180 mm using the header pipe produced in Examples 1 and 2 with a heat exchanger having a height of 150 mm and a width of 180 mm using a cylindrical header pipe, The effective front area increased by 9.4%, and the heat exchange performance was measured. As a result, the performance improved by 9% or more in proportion to the increase in the effective front area.

  Therefore, according to the square tube 20 manufactured according to the first and second embodiments, it is possible to obtain a rectangular tubular header pipe with a uniform cladding ratio and excellent notch-proof strength. Moreover, according to the heat exchanger using the square tube 20, compared with the heat exchanger using the conventional cylindrical header pipe, a front effective area can be increased and the heat exchanger performance in the same space can be improved. it can.

It is the perspective view (a) and principal part expanded sectional view (b) which show an example of the heat exchanger using the header pipe which concerns on this invention. It is a schematic sectional drawing which shows an example of a drawing processing apparatus. It is sectional drawing (a) in alignment with the II line | wire in FIG. 2, sectional drawing (b) in alignment with II-II line, and sectional drawing (c) in alignment with III-III line. It is a flowchart which shows the preparation procedure of the header pipe which concerns on this invention. It is a flowchart which shows another preparation procedure of the header pipe which concerns on this invention.

Explanation of symbols

1 Brazing material 2a, 2b Header pipe 3 Heat exchange tube 4 Corrugated fin 10 Round tube (cylindrical ERW tube)
20 square tube (square tube)

Claims (3)

By brazing together a pair of header pipes each formed of an aluminum member, a plurality of heat exchange tubes laid in parallel between the header pipes, and a fin interposed between the heat exchange tubes A header pipe used in a heat exchanger that is integrally fixed,
A header pipe for a heat exchanger, characterized in that a cylindrical ERW tube having a brazing material clad on at least one of an inner surface and an outer surface is formed into a rectangular tube shape by drawing. By brazing together a pair of header pipes each formed of an aluminum member, a plurality of heat exchange tubes laid in parallel between the header pipes, and a fin interposed between the heat exchange tubes A method of manufacturing a header pipe used in a heat exchanger that is integrally fixed,
Forming a cylindrical tube by electro-sewing a brazing sheet clad with brazing material on at least one of the front and back surfaces;
Forming a rectangular pipe for a header pipe by drawing the cylindrical pipe, and a method for producing a header pipe for a heat exchanger. In the manufacturing method of the header pipe for heat exchangers of Claim 2,
A method of manufacturing a header pipe for a heat exchanger, wherein the drawing is performed a plurality of times to form a square tube for a header pipe having a predetermined thickness.

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