WO2005047798A1

WO2005047798A1 - Multi-hole tube for heat exchanger and method of expanding tube therefor

Info

Publication number: WO2005047798A1
Application number: PCT/JP2004/007935
Authority: WO
Inventors: Kihachiro Koga
Original assignee: Hidaka Seiki Kabushiki Kaisha
Priority date: 2003-11-12
Filing date: 2004-06-07
Publication date: 2005-05-26
Also published as: JP2005164221A

Abstract

A multi-hole tube for a heat exchanger capable of preventing heat exchange efficiency from being lowered due to the less adherence of dirt and water droplets thereto and a method of expanding a tube capable of easily and securely expanding the tube by using a rather small device in the multi-hole tube for the heat exchanger. The multi-hole tube (30) for the heat exchanger in which a plurality of flow passages (31) are formed is characterized in that the outline of the tube in cross section is formed in an oval shape.

Description

Specification

TECHNICAL FIELD The present invention relates to a multi-hole tube for a heat exchanger and a method for expanding the multi-hole tube for a heat exchanger.

The present invention relates to a multi-hole tube for a heat exchanger in which a plurality of flow paths are formed inside a tube for a heat exchanger used in a heat exchanger, and a method for expanding such a multi-hole tube for a heat exchanger. About.

^ Scenic technology

[0002] Heat exchangers such as coolers for home use and automobiles are composed of a plurality of heat exchanger fins formed of a thin plate of aluminum or the like, and a metal heat exchanger tube. Refrigerant flows through the heat exchanger tube, and heat is exchanged through the fins.

It has been conventionally known to use a multi-hole tube as shown in FIG. 14 as such a heat exchanger tube (for example, Patent Document 1).

In the multi-hole tube 10 for a heat exchanger as shown in FIG. 14, since a partition wall 12 for partitioning a plurality of flow paths 11 is formed inside, the contact area of the refrigerant is increased, and the tube is compared with a single-hole tube. Higher heat exchange efficiency.

The multi-hole tube 10 for a heat exchanger has a flat cross section. If the flat shape is inserted into the heat exchanger fins (not shown) so as to be parallel to the air flow direction A by providing the flat shape, the multi-well tube 10 for the heat exchanger is received. This is because air resistance can be reduced and heat exchange efficiency can be increased. Generally, not only the multi-hole tube but also the heat exchanger tube is inserted into the through hole with the collar of the fin, and then the heat exchanger tube and the fin are firmly joined and integrated by heat exchange. It is common practice to expand dexterous tubes.

Here, if the heat exchanger tube is a single-hole tube instead of a multi-hole tube, the tube can be easily expanded using an expansion burette (for example, see Patent Document 2). However, in the case of a multi-hole tube, there is a problem in how to expand each of the flow paths that is not circular or the like, so a method using this expanded burette is adopted. Therefore, there has been proposed an idea of expanding a pipe by flowing a high-pressure fluid. Patent Document 1: JP-A-8-73973

Patent Document 2: JP-A-7-124670

Disclosure of the invention

In the multi-hole tube for a heat exchanger having a flat cross section as described above, there is a possibility that dust may accumulate on a flat portion or water droplets may adhere. In such a case, there is a problem that the heat exchange efficiency is deteriorated because the flow of air is hindered. When the multi-hole tube for a heat exchanger is integrated with the fins, it can be expanded in the short axis direction of the flat tube, but is difficult to expand in the long axis direction. For this reason, there is a problem in that the heat exchange efficiency may be poor at the end of the multi-hole tube for a heat exchanger in the long axis direction because the end cannot be reliably contacted with the fin.

Furthermore, in the case of hydraulic expansion, it is necessary to repeat experiments with various liquids in order to find out what liquid is best to use.

The present inventor has studied to solve the above problems, and as a result, it has been found that the multihole tubes for a heat exchanger are not flat, and the shape of a plurality of internal flow paths is devised to solve the above problems. The present inventor has found out what can be done and arrived at the present invention.

Therefore, an object of the present invention is to provide a multi-hole tube for a heat exchanger that can prevent dust and water droplets from adhering and preventing a decrease in heat exchange efficiency, and a method for expanding such a multi-hole tube for a heat exchanger. It is in.

ADVANTAGE OF THE INVENTION According to the multi-hole tube for heat exchangers which concerns on this invention, in the multi-hole tube for heat exchangers in which several flow paths were formed, the external shape of the cross section of the whole tube is formed in the opal shape. Features. By making the multi-hole tube for the heat exchanger an oval cross section, even if dirt and water droplets adhere to the outer wall surface of the tube, the outer wall surface is a curved surface, so it slips off quickly, and the dirt and water droplets This can prevent the heat exchange efficiency from lowering due to the adhesion and prevent the situation.

The meaning of the opal in the present specification is a shape including an oval and an ellipse, and means a shape in which at least a major axis and a minor axis are present and no plane portion is present. Also, the odd number of the plurality of flow paths are formed, and the flow path having the largest cross-sectional area among the odd number of flow paths is provided at the center of the tube cross section in the major axis direction and the minor axis direction. It may be a sign.

According to this configuration, since the same number of flow paths are disposed on both sides in the long axis direction as viewed from the flow paths positioned at the center in the long axis direction and the short axis direction, only the flow path existing at the center is expanded. By doing so, the tube is uniformly expanded in the longitudinal direction of the tube cross section. If only the flow path having the largest cross-sectional area is expanded, the outer shape of the tube can be expanded toward the short axis and the long axis.

According to the method for manufacturing a heat exchanger tube according to the present invention, there is provided a method for expanding a multi-hole tube for a heat exchanger according to claim 2, wherein the tube is provided at the center in the major axis direction and the minor axis direction of the tube cross section. It is characterized in that the entire tube is expanded by inserting the expansion burette into only the flow path in which the tube is located, and expanding the flow path provided at the center in the long axis direction and the short axis direction of the tube cross section. .

By adopting this method, the expansion of the multi-hole tube has been considered to have to be carried out by a fluid in the past. Only the flow path located at the center in the long axis direction and the short axis direction has been considered. Can be expanded mechanically.

[0004] Effects of the invention

ADVANTAGE OF THE INVENTION According to the multi-hole tube for heat exchangers of this invention, since the cross section was made into the opal shape and the flat part was eliminated, it can be set as the heat exchanger with good heat exchange efficiency which is hard for dust and water droplets to adhere.

Further, according to the method for expanding a multi-hole tube for a heat exchanger of the present invention, a heat exchanger can be provided at low cost. In addition, since it is possible to reliably expand the pipe in the long axis direction, it is possible to surely make contact with the fins, thereby providing a heat exchanger having high heat exchange efficiency.

Brief Description of Drawings

FIG. 1 is a perspective view showing the overall configuration of a multi-hole tube for a heat exchanger.

FIG. 2 is a cross-sectional view of the multi-hole tube for a heat exchanger according to the first embodiment.

FIG. 3 is a cross-sectional view of a multi-hole tube for a heat exchanger according to a second embodiment. FIG. 4 is a sectional view of a multi-hole tube for a heat exchanger according to a third embodiment.

FIG. 5 is a perspective view showing an overall configuration of a multi-hole tube for a heat exchanger according to a fourth embodiment.

FIG. 6 is a sectional view of a multi-hole tube for a heat exchanger according to a fourth embodiment.

FIG. 7 is an explanatory diagram showing a structure of a heat exchanger.

FIG. 8 is an explanatory view showing a structure of a fin.

FIG. 9 is an explanatory view showing a state where a multi-hole tube for a heat exchanger is passed through the fins of FIG. 8.

FIG. 10 is an explanatory view showing a method for expanding the multi-hole tube for a heat exchanger shown in Example 1.

FIG. 11 is an explanatory view showing a state of expansion of the multi-hole tube for a heat exchanger shown in Example 1.

FIG. 12 is an explanatory view showing a method for expanding the multi-hole tube for a heat exchanger shown in Example 4.

FIG. 13 is an explanatory view showing a state of expansion of the multi-hole tube for a heat exchanger shown in Example 4.

FIG. 14 is an explanatory view illustrating the structure of a conventional multi-hole tube for a heat exchanger. BEST MODE FOR CARRYING OUT THE INVENTION

A plurality of flow paths were formed in a multi-hole tube for a heat exchanger having an overall oval cross section. At this time, the plurality of flow paths were arranged in series along the longitudinal direction of the tube cross section. In addition, the flow path located at the center in the major axis direction and the minor axis direction of the tube cross section has a shape in which four sides of a rectangle that is long in the minor axis direction of the cross section are formed in an arc shape.

More specifically, each side of the flow path has an arc shape in which two opposite sides in the long axis direction are convex toward the outside of the flow path, and the two opposite sides in the short axis direction are the flow path. It is formed so as to have an arc shape that is convex toward the inside of the circle.

When such a multi-hole tube for a heat exchanger is expanded when joining it to a fin, only the almost square flow path located at the center is expanded by inserting an expansion burette, and the entire tube is also expanded. The tube was expanded.

Example 1 Hereinafter, examples of the multi-hole tube for a heat exchanger will be described.

Figure 1 shows the overall configuration of the multi-hole tube for a heat exchanger. A multi-hole tube for a heat exchanger (hereinafter simply referred to as a multi-hole tube) 30 is inserted into a fin for a heat exchanger (see FIG. 7; hereinafter, simply referred to as a fin) to allow a refrigerant to flow therethrough. Things. The multi-hole tube 30 has therein a plurality of flow paths 31 partitioned by a partition wall 32, and thus has a characteristic that the heat exchange efficiency can be increased by increasing the contact area of the refrigerant. are doing.

The multi-hole tube 30 is made of aluminum or copper, and is formed by extrusion. Therefore, the outer peripheral wall 33 of the multi-hole tube 30 and the respective partition walls 32 for forming the internal flow path are formed integrally. It is also preferable to improve the mechanical properties of the multi-hole tube formed by extrusion processing by heat treatment (so-called annealing). Specifically, in the case of a multi-hole tube made of Anore Minim, by heating to 400 ° C ± 50 ° C after extrusion, the tube can be expanded well in the longitudinal direction of the tube cross section.

The method of manufacturing the multi-hole tube 30 is well known in the art, and thus will not be described in detail here.

FIG. 2 shows a cross section of the multi-hole tube 30 of the present embodiment. The entire cross section of the multi-hole tube 30 is formed in an oval shape. Here, specifically, the ratio of the length in the major axis direction X to the minor axis direction Y is about 4: 1.

Inside the multi-hole tube 30 having such an oval cross section, five channels 31 having an oval cross section are formed. Among the five flow paths, the flow path 31a having the largest diameter is disposed at the center of the tube cross section in the long axis direction X, and the center of the flow path 31a is aligned with the center of the tube cross section in the short axis direction Y. I do.

The channels 31b having the next largest diameter are arranged on both sides of the channel 31a in the long axis direction. Further, a flow path 31c having the smallest diameter is arranged on the end side of the flow path 31b in the long axis direction.

In other words, the five flow paths 31a to 31c having an oval cross section are arranged in series in the longitudinal direction of the entire tube. At this time, the partition walls 32 are arranged in contact with each other in the longitudinal direction X of the entire tube. Each of these partition walls 32 is arranged in the short axis direction Y of the entire tube. It is arranged in contact with the inner wall surface 35 of the tube.

The flow passages formed inside the multi-hole tube 30 include not only flow passages 31a-31c having an oval cross section or a circular cross section, but also the circular holes existing outside thereof. The non-bar-shaped part 3 Id is also a flow path.

Example 2

FIG. 3 shows another embodiment of the multi-hole tube.

The multi-hole tube 40 is formed in an oval shape as a whole, and has a shape in which the ratio of the length in the major axis direction X to the minor axis direction Y is about 3: 1. Therefore, the shape is such that the thickness is increased in the short axis direction Y as compared with the multi-hole tube 30 shown in the first embodiment.

In the present embodiment, five oval-shaped flow paths 41 are formed inside an opal-shaped multi-hole tube 40 in the overall section. Among the five flow paths, the flow path 41a having the largest diameter is disposed at the center of the entire tube in the long axis direction X, and the center of the flow path 41a coincides with the center of the short axis direction Y. Channels 41b having the next largest diameter are arranged on both sides of the channel 41a in the long axis direction. Further, a flow path 41c having the smallest diameter is disposed on the end side of the flow path 41b in the long axis direction.

That is, the five oval-shaped flow paths 41a to 41c are arranged in series in the longitudinal direction of the entire tube. At this time, the partition walls 42 are arranged in contact with each other in the longitudinal direction X of the entire tube. Each of these partition walls 42 is disposed in contact with the inner wall surface 45 of the tube in the short axis direction Y of the entire tube.

In addition, the flow path formed inside the multi-well tube 40 is not only a flow path 41a-41c having an oval cross-section but a circular cross-section. The part 41d is also a flow path.

The arrangement of such flow paths is the same as in the first embodiment.

Example 3

FIG. 4 shows another embodiment of the multi-hole tube.

The multi-well tube 50 is formed in an oval shape as a whole, but has a shape in which the ratio of the length in the major axis direction X to the minor axis direction Y is about 3: 1. Therefore, the overall shape is the same as that of the multi-well tube 40 shown in the second embodiment. In this embodiment, inside the multi-hole tube 50 having an opal-shaped cross section, three channels 51 having an opal-shaped cross section are formed. Of the three channels 51, the largest diameter channel 51a is arranged at the center of the entire tube in the long axis direction X, and the center of the channel 51a coincides with the center in the short axis direction Y . The other flow paths 51b are respectively arranged on both sides of the flow path 51a in the long axis direction.

The three flow paths 51a and 51b having an oval cross section are arranged in series in the longitudinal direction X of the entire tube. At this time, the partition walls 52 are arranged in contact with each other in the longitudinal direction X of the entire tube. These partition walls 52 are arranged in contact with the inner wall surface 55 of the tube in the short axis direction Y of the entire tube.

In addition, the flow path formed inside the multi-well tube 50 includes a flow path 51a-51b having an oval cross-section and a circular cross-section. Is also a flow path.

In Examples 1 to 3, an odd number of flow paths having a circular cross section or an opal-shaped cross section were provided, and these were arranged on a straight line (on a line parallel to the major axis direction X of the tube cross section). Each flow path having a circular cross section or an opal cross section is formed by a narrow partition wall having the same shape as the flow path, and the partition walls come into contact with each other in the longitudinal direction X of the tube cross section, and the cross section of the tube cross section is formed. On the Y side in the short axis direction, the shape is such that it comes into contact with the inner wall surface of the tube outer peripheral wall.

In this way, by setting the number of flow paths having a circular or opal-shaped cross section to an odd number, if one flow path is arranged at the center of the tube, the same number of flow paths will be placed on both sides of the center flow path. Roads will be laid. Therefore, the entire tube can be uniformly and well-balanced by simply expanding only one channel disposed at the center.

Example 4

5 and 6 show other embodiments of the multi-well tube.

The multi-hole tube 70 has an opal-shaped cross section as a whole, and has a plurality of flow paths 72a, 72b 'formed therein. Of the plurality of flow paths, the flow path 72a located at the center in the major axis direction X and the minor axis direction Y has a cross section that is not circular or opal-shaped. Specifically, the cross-sectional shape of the flow path 72a is such that each side of a long rectangle in the short-axis direction Y is This is a shape formed in an arc shape (curve).

The cross-sectional shape of the flow channel 72a of this embodiment will be described more specifically.

The cross-sectional shape of the flow path 72a located at the center is composed of four arc-shaped sides p, q, r, and s. Of the four arc-shaped sides, two opposing sides p and q in the long axis direction X are convex in the arc, and the protruding direction is outward, and the two opposing sides r and s in the short axis direction Y. Has a circular arc convex, and the projection direction is inward. In addition, two opposing sides r and s in the short axis direction Y are shorter in length than two opposing sides p and q in the long axis direction X. The radii of curvature of these four sides p, q, r, s are almost the same.

A plurality of flow paths 72b having a circular cross section are formed on both sides in the long axis direction X of the flow path 72a located at the center of the long axis direction X of the multi-well tube 70. A total of four circular flow paths 72b are formed, two on each side of the flow path 72a (end side in the long axis direction X). The diameters of the flow paths 72b having a circular cross section are all the same.

Unlike the embodiments described above, in the present embodiment, the entire flow paths 72a and 72b are formed in an oval shape, rather than being formed by a thin partition wall. The tube is hollowed out to give a shape as if formed.

Therefore, the part which can be said to be a partition wall has the same thickness as the diameter of each flow path, and the parts other than the flow path 72a located at the center and the circular flow path 72b (except for five places) Is not formed.

Also, the method for manufacturing the multi-hole tube 70 can be formed by extrusion or drawing in the same manner as in the above-described embodiments.

Example 5

Hereinafter, a method for expanding the multi-hole tube as described above will be described.

First, a description will be given of a configuration of a heat exchanger which is a premise of expanding a multi-hole tube.

As shown in FIG. 7, the heat exchanger 60 is provided so that a plurality of thin fins 36 made of metal are stacked, and the multi-hole tubes 30 are inserted through the stacked fins 36, respectively. The multi-hole tube 30 is joined to and integrated with the fin 36 by being expanded over its entire length.

As described above, expansion of the multi-hole tube 30 joins the multi-hole tube 30 to the fin 36. It is done at the time. Hereinafter, the connection between the fin and the multi-hole tube will be described with reference to FIGS. The multi-hole tube described here is the same as that described in the first embodiment.

As shown in FIG. 8, the fin 36 is a thin metal plate, and has a through hole 38 formed at a predetermined position so that the multi-hole tube 30 can be inserted therein. The periphery of the through hole 38 is provided with a collar 39 formed so as to stand in one direction, and is configured as a through hole 46 with a collar. The multi-hole tube 30 is inserted into such a collared through hole 46 of the fin 36. When the multi-hole tube 30 is expanded after the multi-hole tube 30 is inserted into the through-hole 46 with the collar, the outer wall surface of the multi-hole tube 30 comes into close contact with the collar 39 and is integrated with the fin 36 as shown in FIG. It becomes.

FIG. 10 is a schematic explanatory view of the method for expanding a multi-hole tube according to the present invention, and FIG. 11 shows a state of expanding the multi-hole tube at this time. In FIG. 11, the broken line indicates the state before expansion, and the solid line indicates the state after expansion.

The multi-hole tube 30 described below is the multi-hole tube described in the first embodiment, and has an oval cross section as a whole, and has five oval-shaped flow channels 31 disposed therein. It is. More specifically, a flow path 31a having the largest diameter among the oval cross-sections is disposed at the center of the entire major axis direction X, and the force S directed gradually toward the end in the major axis direction X is gradually increased. The small-diameter flow paths 31b and 31c are arranged, and the partition walls 32 of the oval-shaped flow paths are in contact with each other, and are arranged in a straight line along the long axis direction X. In addition, each of the flow paths 31 having the same cross-sectional shape is formed so as to inscribe the inner wall surface 35 of the multi-hole tube 30 in the entire short axis direction Y.

The expansion is performed by expanding one of the flow paths 31 having an opal-shaped cross section formed therein with an expansion buret 66. Specifically, an expansion buret 66 is inserted into a flow path 31a (hereinafter, referred to as a center flow path) arranged at the center in the major axis direction X and the minor axis direction Y, thereby expanding the pipe. It is.

When the expansion burette 66 enters the central flow channel 31a, the central flow channel 31a is entirely expanded in all directions around 360 degrees. Is pressed (arrow B in FIG. 11). This partition 32bl pushes By being pressed, the center position of the flow path 31b adjacent to the center flow path 31a moves to the end 37 side in the long axis direction X, so that the partition wall 32b2 on the end 37 side of the flow path 31b further ends. The partition wall 32cl forming the flow path 31c adjacent to the part 37 is pressed (arrow C in FIG. 11). Since the partition wall 32c2 on the end 37 side of the flow path 31c is in contact with the vicinity of the end 37, the partition 32c2 expands the vicinity of the end 37 in the longitudinal direction X.

On the other hand, the central flow channel 31a is entirely expanded in all directions around 360 degrees, but presses the outer peripheral wall 33 of the entire multi-hole tube 30 at a portion facing the short axis direction γ (arrow D in FIG. 11). Expand the entire tube in the short axis direction Y as well.

It should be noted that a conventionally known pipe burette 66 can be employed.

Specifically, the expansion burette 66 has a predetermined diameter that is the same as the inner diameter of the central flow path 31a of the multi-hole tube 30 after expansion, and is shown at the tip of the expansion mandrel 68. N, it is mounted by the mounting member.

In the above-described method for expanding a multi-hole tube, a tube having five opal-shaped flow channels formed was expanded. However, the number of opal-shaped flow paths is not limited to five, but may be other numbers, but an odd number is preferable.

Further, in the above-described embodiment, the internal flow path may be a force-recessed circular flow path having a cross section of an opal shape.

Example 6

Next, a method of expanding the multi-hole tube shown in FIGS. 5 and 6 will be described with reference to FIGS.

The multi-hole tube 70 described here has a cross-sectional shape of a flow path 72a located at the center in the long axis direction X and the short axis direction Y among a plurality of flow paths. The sides are formed in an arc shape. Of the four arc-shaped sides, two opposing sides p and q in the long axis direction X have outward projections in which the arcs are convex and short axes. Opposite sides r and s in the direction Y are such that the protruding direction in which the arc is convex is inward.

By inserting a known expansion burette 66 into the flow path 72a, the entire multi-hole tube 70 is expanded.

That is, the diameter of the expanded burette 66 is the width h (that is, the width It has a larger diameter than the width h) in various directions. When the expansion burette 66 is inserted into the flow path 72a, the flow path 72a is expanded in the long axis direction X and the short axis direction Y, and the cross section of the flow path 72a becomes circular (a portion indicated by a broken line E in FIG. 13). When the flow path 72a is expanded, the wall around the flow path 72a expands outward, and the entire multi-hole tube 70 is expanded (broken line F in FIG. 13).

Although various embodiments have been described above with reference to preferred embodiments of the present invention, the present invention is not limited to the embodiments, and it goes without saying that many modifications can be made without departing from the spirit of the invention.

Claims

The scope of the claims

[1] In a multi-hole tube for a heat exchanger having a plurality of channels formed therein,

A multi-hole tube for a heat exchanger, wherein the outer shape of the tube cross section is formed in an opal shape.

[2] An odd number of the plurality of flow paths are formed,

2. The multi-hole tube for a heat exchanger according to claim 1, wherein the flow passage having the largest cross-sectional area among the odd-numbered flow passages is provided at the center of the tube cross section in the major axis direction and the minor axis direction. .

[3] A method for expanding a multi-hole tube for a heat exchanger according to claim 2,

The expansion burette is inserted only into the flow path provided at the center in the long axis direction and short axis direction of the tube cross section, and the flow path provided at the center in the long axis direction and short axis direction of the tube cross section is expanded. A method for expanding a multi-hole tube for a heat exchanger, wherein the entire tube is expanded.