JP2001059689A - Tube for heat exchanger - Google Patents

Abstract

PROBLEM TO BE SOLVED: To improve moldability and heat exchanging performance in a tube for a heat exchanger having high pressure resistant request by arranging a heat transfer enlarging part having a medium channel not formed at both or one side end of a tube section, and perforating a hole in which a medium does not flow, in the enlarging part. SOLUTION: The tube 2 for a heat exchanger comprises a plurality of refrigerant channels 9 formed at its center to communicate in a longitudinal direction, and a heat transfer enlarging part 2a arranged at both or one side end to enlarge a heat transfer area. Then, to assure high pressure resistance, its sectional shape is formed in a circular shape. Meanwhile, A hole 10 of a rectangular section coincident with a sector flat surface shape of the tube 2 is perforated at the part 2a. In the case of extrusion molding the tube 2 of a metal material or the like, a core material for forming the hole 10 is disposed at a part for arranging the part 2a to improve moldability. The tube 2 can be reduced in weight and cost by such a hole 10, and its heat transfer area is increased.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a heat exchanger for performing heat exchange by radiating heat from a tube through a medium flowing between heat exchange cycles.

[0002]

2. Description of the Related Art Conventionally, there has been known a heat exchanger formed by connecting a heat exchange tube for exchanging heat of a refrigerant with a pair of header pipes for receiving and sending the refrigerant.

That is, the medium taken in from one header pipe flows through the medium flow path inside the heat exchange tube, and the medium transfers heat to the fins mounted on the tube surface and between the tubes, and exchanges heat with the outside air. After that, it is discharged from the other header pipe. The heat exchange tube used in this type of heat exchanger is formed by using an aluminum and / or aluminum alloy or the like as a material by a manufacturing method by extrusion molding or the like.

Further, the heat exchanger has fins which are in contact with the heat exchange tubes, and is formed so that the cross section of the heat exchange tubes has a flat shape in order to increase the contact area between the heat exchange tubes and the fins. A plurality of medium channels are formed in the flat tube.

[0005]

In recent years, chlorofluorocarbon-based refrigerants cause global warming and the like, and therefore there is an increasing demand for the ban on the use of these refrigerants and the direction of reduction. As an alternative to the CFC-based refrigerant, for example, CO 2
A heat exchange cycle using ₂ as a refrigerant is used.

When CO ₂ is used as a refrigerant in a refrigeration cycle, heat is radiated from the refrigerant which has become high temperature and high pressure.
The state of the refrigerant when flowing through the heat exchanger is in a supercritical region beyond the critical point of the gas-liquid two-phase state, and when the normal refrigerant in the gas-liquid two-phase state flows through the heat exchanger. By comparison, it is assumed that excessive pressure is applied to the heat exchanger. For example, C
When O ₂ is used as the refrigerant, the heat exchanger that exerts the heat radiation effect of the high-temperature and high-pressure refrigerant is required to have a pressure resistance of at least six times that of the case where the refrigerant in the gas-liquid mixed state flows. It is considered to be.

[0007] For example, the invention described in Japanese Patent Application Laid-Open No. 10-311697 discloses a radiator for performing heat exchange of a medium in a supercritical state.

When CO ₂ is used as a medium, in order to secure the required pressure resistance, members such as a tube and a header pipe for a heat exchanger through which a refrigerant flows are made thick to ensure pressure resistance. It is possible.

However, as shown in FIG.
7 and the thickness of the header pipe 4 are increased, the inner diameter of the medium flow path of the header pipe 4 is reduced, and the inner diameter of the medium flow path of the header pipe 4 is reduced.
The insertion portion 27e of the tube to be inserted into the tube becomes smaller. It is conceivable that the end portion of the tube 27 is brought into contact with the refrigerant passage of the header pipe without depending on the tube insertion portion 27e, but the tube joined between the pair of header pipes 4 so as not to leak the medium. It is difficult to regulate the length, and generally, the tubes are connected by inserting a tube end into a tube insertion hole formed in the header pipe.

When the tube is formed according to the size of the tube insertion hole formed in the header pipe, the plane area of the tube is reduced, the contact area between the tube and the fin is reduced, and the heat exchange performance is reduced. The problem arises.

For this reason, at the longitudinal end of the tube 27, a heat transfer expansion portion 27a in which a medium flow path is not formed is provided at both ends of the cross section of the tube, and at the longitudinal end of the tube inserted into the header pipe 4, A tube provided with an insertion portion 27e that matches the tube insertion hole of the header pipe 4 by cutting the heat transfer expansion portion 27a is conceivable. In this way, when the heat transfer expansion portion is provided and the tube insertion portion is formed, the heat transfer area of the tube is secured, and the heat exchange performance is maintained.

When the tube 27 provided with the heat transfer enlarged portions 27a at both ends of the cross section is formed by extrusion molding, the mold to be formed has a portion where the refrigerant flow path is formed dense, and the heat transfer without forming the refrigerant flow path is performed. The enlargement is sparse. When forming a tube by extrusion, the sparse part of the mold for extrusion molding has less resistance due to the mold, so that the material concentrates on the sparse part and the material spreads evenly on the dense part. Therefore, there is a problem that the product yield is poor when extruded with the same pressure.

Therefore, the present invention has been made in view of the above problems,
An object of the present invention is to provide a tube for a heat exchanger having high pressure resistance, which has good formability and excellent heat exchange performance.

[0014]

According to the first aspect of the present invention, there is provided a tube for a heat exchanger provided with a medium flow path through which a medium flows in a longitudinal direction, wherein the tube has two ends or a cross section of the tube. A tube for a heat exchanger having a heat transfer expansion section at one end where a medium flow path is not formed, and a hole section through which the medium does not flow in the heat transfer expansion section.

When forming a tube with high pressure resistance,
In order to satisfy the required pressure resistance, a tube in which the heat transfer expansion portions are formed at both ends of the tube cross section in the longitudinal direction of the tube is considered.

When such a tube is formed by extrusion, the extrusion die is in a dense state in which a mandrel (core material) is provided at a portion where a refrigerant flow path is formed.
In addition, no member is provided at a portion where the heat transfer expansion portion is formed, and the portion is in a sparse state.

Thus, the mold used for extrusion molding is as follows:
Extruded material concentrates on the sparse part when there is a sparse part and a dense part, and since the sparse part has little resistance due to the mold, the fluidity of the material is improved, and the material is evenly distributed. It may not be distributed and may cause poor molding of the tube.

According to the present invention, the material is evenly distributed to the heat transfer enlarged portion of the tube by providing the core material and extruding the same at the heat transfer expanded portion of the tube, and the moldability of the tube is improved. In addition, in the mold for extrusion molding,
Since the load due to the material is evenly applied, the tube can be formed without causing molding failure or failure of the mandrel.

Since the formed tube has a hole in the heat transfer expanding portion, the required pressure resistance is secured, the heat transfer area is increased, the heat exchange performance is improved, and the member is formed. And the manufacturing cost can be reduced.

According to a second aspect of the present invention, in the first aspect, the tube has a thickness from the outer surface of the tube to the inner surface of the hole through which the medium does not flow, The thickness of the tube from the outer surface of the tube to the inner surface of the refrigerant flow path is larger than the thickness of the tube.

In the case where a hole is formed in the heat transfer expansion portion formed to secure a heat transfer area, the thickness of the tube from the outer surface of the tube to the inner surface of the hole through which the medium does not flow is determined by the thickness of the tube. If it is configured to be larger than the thickness of the tube from the outer surface to the hole of the tube, the heat resistance does not increase due to the thickness of the tube, so that heat transfer can be secured and the heat exchange performance can be improved. .

According to a third aspect of the present invention, in a tube for a heat exchanger having a medium flow path through which a medium flows in a longitudinal direction, the tube has a medium flow path at both ends or one end of the tube cross section. A heat transfer expansion section that is not formed is provided, and an open section that opens toward the outside of the tube is provided in the heat transfer expansion section where the medium flow path is not formed.

In the tube, an open portion that opens toward the outer surface of the tube is formed in the heat transfer expanding portion provided for expanding the heat transfer area. Since only the portion constituting the road does not become dense, and the core material is also installed and extruded at the portion constituting the open portion, the load due to the material becomes uniform and the moldability is improved.

In the formed tube, the heat exchange performance is improved by securing a heat transfer area, and the formation of the open portion can reduce the weight of the tube and reduce the product cost.

According to a fourth aspect of the present invention, in any one of the first to third aspects of the present invention, the cross-sectional shape of the medium flow path is circular. The cross-sectional shape of the hole is configured so as to conform to the outer peripheral shape of the heat transfer expanding portion.

As described above, when the cross section of the medium flow path of the tube is circular, stress concentration applied to the medium flow path can be reduced, and high pressure resistance can be secured.

Here, the circular shape may be a perfect circle having the same radius, an elliptical shape having a major axis and a minor axis, or a similar circular shape.

On the other hand, the shape of the hole formed in the heat transfer expanding portion does not need to be as described above, and thus the shape thereof is not limited. May be considered. The invention described in claim 5 of the present application is the invention according to any one of claims 1 to 5, wherein the heat transfer expansion portion of the tube is formed so as to be flush with a portion where a medium flow path is formed. ing.

Therefore, fins can be attached to the heat transfer expansion portion of the tube, and the heat transfer area can be increased, and the heat exchange performance can be improved.

[0030]

FIG. 1 is a plan view showing a schematic configuration of a heat exchanger according to this embodiment.

As shown in FIG. 1, for example, the heat exchanger 1
In this configuration, a plurality of heat exchange tubes 2 and fins 3 are alternately laminated, and both ends of the laminated tubes 2 are inserted into and connected to the tube insertion holes of the pair of header pipes 4 and 4, respectively. I have. The header pipe 4 is provided with a coolant passage through which the coolant flows. Header pipe 4
Inside, a partition plate is provided for partitioning the refrigerant flow path formed in the header pipe and the tube into a plurality of sections.
In addition, side plates 5 and 5 are arranged above and below the heat exchanger 1. One of the header pipes 4 has a supply pipe 7 for supplying the refrigerant to the header pipe 4, and the other header pipe 4 has a discharge pipe 8 for discharging the refrigerant from the header pipe 4.

For example, in the refrigerating apparatus provided with the heat exchanger 1 of the present embodiment, when CO ₂ is used as a refrigerant for a refrigerating cycle, the high temperature and high pressure refrigerant exceeds the critical point of the gas-liquid two-phase. Since the heat is radiated in the region, the heat exchanger is required to have a pressure resistance six times or more as compared with the case where the normal refrigerant in the gas-liquid two-phase state flows between the heat exchangers. Therefore, the header pipe 4 and the tube 2 of the heat exchanger 1 are formed with a sufficient thickness to ensure the required pressure resistance.

FIG. 2 is a sectional view showing the tube 2 of the present embodiment, and FIG. 3 is a perspective view of the tube 2 shown in FIG.

As shown in FIG. 2 and FIG.
Is formed with a refrigerant flow passage 9 communicating in the longitudinal direction, and a heat transfer expansion portion 2 for expanding a heat transfer area at both ends of a cross section of the tube.
a.

The medium flow path 9 is formed such that the cross section of the medium flow path has a circular shape in order to ensure high pressure resistance.

In the present embodiment, the cross section of the medium flow path is formed in a shape close to a perfect circle. However, the present invention is not limited to this example, and the medium flow path may be formed in an elliptical shape having a long axis and a short axis. The heat transfer enlargement portion 2 a forms a hole 10 having a rectangular cross section that matches the flat shape of the tube 2. The tube 2 is formed using extrusion molding in which a metal material is extruded into a mold and molded. As described above, when the tube 2 is formed using the mold, a portion where the medium flow path 9 of the tube 2 is formed is provided with a mandrel (core material), and the portion has a dense structure of the mold. I have. On the other hand, the portion constituting the heat transfer expansion portion 2a is sparse because there is no core material. In this way, if there is a sparse part and a dense part in the extrusion mold, the material is concentrated on the sparse part during extrusion molding, and the material does not spread to the dense part,
The moldability is poor, and a load is applied by the material to the mandrel provided in the dense part, resulting in dimensional defects and breakage of the mold.

In this embodiment, since the core material for forming the hole 10 is provided in the portion constituting the heat transfer expansion portion 2a, a sparse portion and a dense portion are not formed in the extrusion mold, and the average is not obtained. As a result, the thickness of the tube is made uniform, the extrudability is improved, and dimensional defects and mold breakage can be avoided. For example, since it is easier to provide the core material to be connected to one mold in order to form the hole 10, the hole formed in the heat transfer enlarged portion 2 a of the tube 2 formed by extrusion molding is easy. The part 10 is formed in a shape communicating with the tube 2 in the longitudinal direction.

When the hole 10 is formed in the heat transfer expanding portion of the tube 2 as in this example, the weight of the tube 2 and the material cost can be reduced.

The hole 10 formed in the heat transfer expansion portion 2a of the tube 2 does not allow a medium to flow therethrough.
The cross-sectional shape of the hole 10 is not limited to a circular shape, but may be any shape that matches the shape of the tube 2. Also, if the cross-sectional area of the hole 10 is increased, the thickness 2c from the outer surface 2b of the tube 2 to the inner surface of the hole 10 is reduced, and the thermal resistance is increased. From 2b,
It is desirable that the thickness 2c reaching the inner surface of the hole 10 be larger than the thickness 2d reaching the inner surface of the medium flow path 9 from the outer surface 2b of the tube 2.

The heat transfer expansion section 2 formed in the tube 2
a is formed so as to be flush with the outer surface 2b of the tube 2. Therefore, when the fins 3 are mounted on the tube 2, the mounting range can be expanded to the heat transfer expansion portion 2a of the tube 2, and the heat transfer area can be expanded.
The amount of heat radiation increases, and the heat exchange performance can be improved.

FIG. 4 shows a heat transfer expansion portion 20a of the tube 20.
FIG. 6 is a sectional view showing a tube 20 and a fin 3 in which a hole 11 having another sectional shape is formed.

As shown in FIG. 4, the hole 11 formed in the heat transfer enlarged portion 20a of the tube 20 is different from the hole 10 and, like the medium flow path 9, the hole 11 of the present embodiment is The cross section is formed in a circular shape.

The hole 12 formed in the expanded heat transfer portion 21a of the tube 21 shown in FIG. 5 has a rectangular cross section.

As described above, the shapes of the holes 11 and 12 can be easily changed by the shape of the core material.

The tube 22 shown in FIG.
The hole 14 having a circular cross section is formed in the heat transfer expansion portion 22a of
Holes 14a, gradually toward both ends of the cross section of the tube 2,
The diameters of 14b and 14c are increased.

As shown in FIG. 6, when the diameter of the hole portion 14 formed in the heat transfer enlarged portion 22a of the tube 22 is gradually increased, the tube 22 in the ventilation direction (arrow in FIG. 6)
, That is, the thickness from the outer surface 22b of the tube 22 to the inner surfaces of the holes 14a, 14b, and 14c is gradually reduced, so that the heat conductivity is improved and the heat exchange efficiency of the portion in contact with the outside air is improved. Thus, the heat exchange performance of the tube 22 is improved.

In addition, as shown in FIG.
In 4, a heat transfer expansion portion 24 a is formed on one side of a cross section of the tube 24, and a hole 15 is formed in the heat transfer expansion portion 24 a.

As described above, the heat transfer expanding portion 24 is formed on one side of the cross section of the tube 24, and the hole 1 is formed in the heat transfer expanding portion 24a.
When the hole 5 is formed, if it is installed on the windward side in the ventilation direction (the arrow in FIG. 7 indicates the ventilation direction) on the side where the hole 15 is formed, the heat of the medium transmitted to the heat transfer expansion section 24 is removed. The tube 2 having a medium flow path 16 through which heat of a high-temperature medium flows through the outside air which is sufficiently cooled by the outside air and has a cooling effect.
4, the cooling efficiency of the tube 24 can be improved.

FIG. 8 is a view showing a state where the tube 24 shown in FIG. 7 is joined to the header pipe 4.

In addition, as shown in FIGS. 9 and 10,
A rectangular or wedge-shaped tube 25, 26 is formed on the heat transfer expansion portions 25a, 26a formed at the cross-sectional ends of the tubes 25, 26.
Opening part 1 opening toward outer surfaces 25b, 26b of 26
It is also conceivable to form 7,18.

As described above, when the wedge-shaped or rectangular core material is set in the extrusion mold, the tubes 25 and 26 formed by the extrusion molding are connected to the tube 2.
Opening portions 17, 18 opening toward the outer surfaces of 5, 26
Is formed.

As described above, since the tubes 25 and 26 are provided with the open portions 17 and 18, the heat transfer area can be ensured, the weight of the members can be reduced, and the manufacturing cost can be reduced.

Since the open section 17 has a wedge-shaped cross section, the thickness of the heat transfer expansion section 25a is gradually reduced, and the heat of the medium can be efficiently cooled.

[0054]

As described above, the present invention relates to a tube for a heat exchanger having a medium flow path through which a medium flows in a longitudinal direction, wherein the tube has a medium flow path at both ends or one end of the tube cross section. Is provided with a heat transfer expansion section where no
A heat exchanger tube having a configuration in which the heat transfer expansion section includes a hole through which a medium does not flow.

According to the present invention, the core material is provided in the expanded heat transfer portion of the tube and extrusion-molded to form a hole in the expanded heat transfer portion of the tube.
The material is evenly distributed in the extrusion mold, and the moldability of the tube is improved. In addition, in the mold for extrusion molding,
Since the material pressure load is evenly applied, the tube can be formed without causing molding failure or failure of the mandrel.

In the formed tube, a hole is formed in the heat transfer expanding portion, so that the required pressure resistance is ensured, the heat transfer area is increased, the heat exchange performance is improved, and the member is formed. And the manufacturing cost can be reduced.

The thickness of the tube extending from the outer surface of the tube to the inner surface of the hole through which the medium does not flow is greater than the thickness of the tube extending from the outer surface of the tube to the inner surface of the refrigerant passage. Largely formed.

When a hole is formed in the heat transfer enlarged portion formed to secure the heat transfer area, the thickness of the tube from the outer surface of the tube to the inner surface of the hole through which the medium does not flow is limited to the thickness of the tube. If it is configured to be larger than the wall thickness of the tube from the outer surface to the hole of the tube, the heat resistance does not increase due to the wall thickness of the tube, so that heat transfer can be secured and the heat exchange performance can be improved. .

The cross section of the medium flow path formed in the tube is formed in a circular shape.

As described above, when the cross section of the medium flow path of the tube is circular, stress concentration applied to the medium flow path can be reduced, and high pressure resistance can be secured.

Since the hole formed in the tube does not allow a medium to flow, the cross-sectional shape of the hole is not limited to a circular shape, but a shape along the outer peripheral shape of the tube, for example, a circular shape or a rectangular shape. And so on. In addition, the heat transfer expansion portion of the tube may have a wedge-shaped cross-section opening toward the outer surface of the tube or an opening having a rectangular cross-section.

When the heat transfer expansion portion of the tube is formed so as to be flush with the portion where the medium flow path is formed,
Fins can be attached not only to the part forming the medium flow path of the tube, but also to the heat transfer expansion part of the tube,
The heat transfer area can be increased to improve the heat exchange performance.

[0063]

[Brief description of the drawings]

FIG. 1 is a diagram showing a schematic configuration of a heat exchanger according to a specific example of the present invention.

FIG. 2 is a cross-sectional view of a tube according to an embodiment of the present invention.

FIG. 3 is a perspective view of the tube shown in FIG. 2 according to a specific example of the present invention.

FIG. 4 is a sectional view showing a tube and fins according to a second embodiment of the present invention.

FIG. 5 is a sectional view of a tube according to a third embodiment of the present invention.

FIG. 6 is a sectional view of a tube according to a fourth embodiment of the present invention.

FIG. 7 is a sectional view of a tube according to a fifth embodiment of the present invention.

FIG. 8 is a plan view showing a state where the tube shown in FIG. 5 is connected to a header pipe.

FIG. 9 is a partial sectional view of a tube according to a sixth embodiment of the present invention.

FIG. 10 is a partial cross-sectional view of a tube according to a seventh embodiment of the present invention.

FIG. 11 is a plan view showing a state in which a header pipe and a tube are connected according to a conventional example.

FIG. 12 is a perspective view showing a tube according to a conventional example.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Heat exchanger 2 Tube 2a Heat transfer expansion part 2b Outer side surface 2c Thickness 2d Thickness 3 Fin 4 Header pipe 5 Side plate 7 Piping 8 Piping 9 Medium flow path 10 Hole 11 Hole 12 Hole 13 Hole 14a Hole Portion 14b Hole portion 14c Hole portion 15 Hole portion 16 Open portion 17 Open portion 20 Tube 20a Heat transfer expansion portion 21 Tube 21a Heat transfer expansion portion 22 Tube 22a Heat transfer expansion portion 23 Tube 23a Heat transfer expansion portion 24 Tube 24a Heat transfer expansion Portion 24b Tube outer surface 25 Tube 25a Heat transfer expansion portion 26 Tube 26a Heat transfer expansion portion 26b Tube outer surface 27 Tube 27a Heat transfer expansion portion 27e Tube insertion portion

Claims (5)

[Claims] 1. A tube for a heat exchanger including a medium flow path through which a medium flows in a longitudinal direction, wherein the tube includes a heat transfer expansion section in which a medium flow path is not formed at both ends or one end of a tube cross section. A tube for a heat exchanger, wherein the heat transfer expansion section is provided with a hole through which a medium does not flow. 2. The thickness of the tube extending from the outer surface of the tube to the inner surface of the hole through which the medium does not flow is formed to be larger than the thickness of the tube extending from the outer surface of the tube to the inner surface of the refrigerant flow path. The tube for a heat exchanger according to claim 1, wherein: 3. A tube for a heat exchanger provided with a medium flow path through which a medium flows in a longitudinal direction, wherein the tube has a heat transfer expansion portion in which a medium flow path is not formed at both ends or one end of a cross section of the tube. A tube for a heat exchanger, wherein an open portion that opens toward the outside of the tube is provided in the heat transfer expansion portion where the medium flow path is not formed. 4. A cross-sectional shape of the medium flow path is circular, and a cross-sectional shape of the hole is a circular shape or a shape along an outer peripheral shape of the heat transfer expanding portion. The tube for a heat exchanger according to claim 1. 5. The heat exchanger according to claim 1, wherein the heat transfer expansion portion of the tube is formed so as to be flush with a portion where a medium flow path is formed. tube.