JP6355473B2 - Heat exchanger - Google Patents

Description

  The present invention relates to a heat exchanger, and more particularly to a heat exchanger using a flat tube joint that connects a flat heat transfer tube having a plurality of flow paths in a tube and a hollow circular tube.

  As one form of a heat exchanger mounted on an air conditioner or a refrigerator, a fin tube type heat exchanger is known which is a combination of a fin formed in a strip shape and a heat transfer tube having a flat cross section. Yes. A heat transfer tube having a flat cross section is provided with a dividing column for dividing the inside of the tube into a plurality of flow paths, and has a feature that a plurality of flow paths through which a refrigerant passes are provided in the pipe. In such a fin tube type heat exchanger, a flat pipe joint is used (for example, Patent Document 1). The flat tube joint connects heat transfer tubes having flat cross sections or connects a heat transfer tube having a flat cross section and a refrigerant pipe using a circular tube.

  The circular pipe is excellent in workability, and it is possible to save the mounting space. The heat transfer tube has a flat cross section. The flat tube portion of the flat tube joint is formed by expanding one end of a round tube into a flat shape and then compressing it into a flat shape (for example, Patent Document 2). In order to form a path for distributing the refrigerant to the heat transfer tubes, it is reasonable to use a circular tube, and a flat tube joint is used to connect the heat transfer tube and the circular tube.

JP 2010-249343 A JP 7-125529 A

  In a finned tube heat exchanger that combines a fin formed in a strip shape and a heat transfer tube having a flat cross section, a flat tube joint is used to connect the heat transfer tube and the circular tube. . The flat pipe joint has a flat shape at one end and a circular shape at the other end, and is formed into a flat shape by plastic working such as pipe expansion on one end of a raw pipe having a circular cross section. Alternatively, by deep drawing from a plate-shaped material, a shape in which one end is flat and the other end is circular is formed.

  In recent years, the heat transfer tube having a flat cross-section has been reduced in the dimension of the short axis side of the flat shape from the viewpoint of improving the performance such as improving the heat transfer performance inside the tube and reducing the ventilation resistance outside the tube. There is a tendency that the dimension on the long axis side is enlarged. Further, in the refrigerant flow path in the pipe, the number of flow paths to be divided is increased from the viewpoint of improving heat transfer performance, and the cross-sectional area of one flow path tends to be further refined.

  As described above, the dimensional ratio on the long axis side with respect to the short axis side of the flat shape increases, so that the amount of deformation of the pipe end increases in the end processing of the pipe, which is a known processing method. If the amount of material elongation at one end of the blank pipe to which plastic deformation is applied increases, the thin pipe will be thinned, and if the processing limit is exceeded, it may break. Even if it can be processed, it becomes difficult to secure a wall thickness for maintaining the pressure resistance performance. In addition, even when forming from a plate-like material by deep drawing, the dimensional ratio of the major axis side to the minor axis side of the flat shape is increased, so that the amount of elongation of the material is increased, and breakage, thinning, etc. The problem has occurred.

  In order to improve the plastic workability, a method for anticipating the amount of thinning after processing, increasing the thickness of the bare tube and base material, and preventing breakage due to elongation and excessive thinning is considered as one possible countermeasure. ing. However, when thick materials are used, the processing equipment becomes larger, the amount of material used increases, and the product weight increases. When a joint shape with a high flatness is formed by end processing of a circular pipe material or deep drawing from a plate material, material fracture due to processing elongation or reduction in pressure resistance performance due to thickness reduction is observed. Furthermore, the cross-sectional area per flow path is reduced by miniaturizing the in-tube refrigerant flow path of the heat transfer tube having a flat cross section.

  When the heat transfer tube and the flat joint are connected by brazing, the molten brazing material travels along the inner wall of the joint and permeates into the refrigerant flow path in the heat transfer tube due to capillary action. At this time, a situation occurs in which the flow path is blocked by wax. The penetration of the wax is more likely to occur as the channel cross-sectional area of the in-tube refrigerant channel of the heat transfer tube having a flat cross section is smaller. If one of the plurality of flow paths is blocked by wax, the refrigerant will not flow and the desired heat transfer performance cannot be ensured. The present application aims to solve such problems in such a heat exchanger, and in particular, to prevent a decrease in heat transfer performance due to blockage of the pipe flow path.

A heat exchanger according to the present invention includes a circular tube having a cylindrical cross section, a heat transfer tube in which a refrigerant flow path is divided by a plurality of partition walls, a plurality of fins joined to the heat transfer tube, and a circular tube A flat joint having an insertion port and a heat transfer tube insertion port, and a relief portion formed at the back of the heat transfer tube insertion port, and the flat joint has two joint members having the same shape Ri but Na are joined, inserting the circular pipe opening, spigot of the heat transfer tube, and the escape portion, respectively, the circular pipe spigot half, half heat transfer tube insertion holes, and relief portions of the half shape, together is formed Te characterized Rukoto.

  According to the present invention, even when the dimensional ratio of the long axis side to the flat axis side of the flat shape is increased, the amount of deformation applied to the raw plate material is small because of the two-part structure. Since the workability from the plate material is improved, it is possible to secure a sufficient thickness of the joint and to ensure a predetermined pressure resistance performance.

It is a perspective view which shows the whole structure of the fin tube type heat exchanger concerning this invention. It is an assembly perspective view which shows the joint structure by Embodiment 1 of this invention. It is a disassembled perspective view which shows the joint structure by Embodiment 1 of this invention. It is detail sectional drawing which shows the joint structure by Embodiment 1 of this invention. It is a disassembled perspective view which shows the joint structure by Embodiment 2 of this invention. It is an assembly perspective view which shows the joint structure by Embodiment 3 of this invention. It is detail drawing which shows the joint structure by Embodiment 4 of this invention. It is an assembly perspective view which shows the joint structure by Embodiment 5 of this invention.

  A heat exchanger according to an embodiment of the present invention will be described below with reference to the drawings. In each figure, the same or similar components are denoted by the same reference numerals, and the sizes and scales of the corresponding components are independent. For example, when the same components that are not changed are illustrated in cross-sectional views in which a part of the configuration is changed, the sizes and scales of the same components may be different. In addition, the configuration of the heat exchanger actually includes a plurality of members, but for the sake of simplicity, only the portions necessary for the description are shown, and the other portions are omitted.

Embodiment 1 FIG.
FIG. 1 is an assembled perspective view showing a fin tube type heat exchanger including a flat joint according to Embodiment 1 of the present invention. The heat exchanger 100 includes a fin 1, a heat transfer tube 2, a flat joint 3, a circular tube 4, a U-bend tube 5, and the like. The fin 1 is formed in a strip shape, and a plurality of fins 1 are laminated at a predetermined interval. The heat transfer tube 2 has a flat cross section and is inserted through the fins 1 at a predetermined interval. The fin 1 and the heat transfer tube 2 are fixed by brazing. An end portion of the heat transfer tube 2 is converted into a circular tube shape via a flat joint 3. A distribution circuit such as a distributor and a header is connected to the end of the circular tube 4. The header collects the refrigerant, and the distributor has a function of distributing the refrigerant to each heat transfer tube.

  The refrigerant 6 is circulated inside the heat transfer tube through the distribution circuit. The U-bend pipe 5 is connected to form a folded flow path in the first and second heat exchangers. In the above configuration, the material for the heat exchanger fin 1 is a thin plate having a thickness of 0.09 to 0.2 mm mainly made of aluminum or an aluminum alloy, and has a surface treatment for anticorrosion, antifouling, hydrophilicity or water repellency. It is desirable that a film is applied. The distance between the fins is determined by the characteristics of the heat exchanger and is generally 1.0 mm to 2.0 mm.

  The fin 1 and the heat transfer tube 2 are joined by brazing after assembly. The fin material is a clad material having a brazing material layer. The fin is clad together with the core material by using an aluminum alloy having a melting point lower than that of the aluminum alloy as the core material as a brazing material layer. The fins 1 and the heat transfer tubes 2 are heated for joining after being assembled. Alternatively, the fin material may be a bare material and a brazing material coated on the heat transfer tube side may be used and heated to be joined in the same manner. Alternatively, the brazing material is bare and the brazing material is not provided on the heat transfer tube side. After assembling the fins and the heat transfer tube, the brazing material is placed or the brazing material is applied by applying paste brazing. Similarly, there is a method of heating and joining.

  FIG. 2 is an assembled perspective view showing the configuration of the joint structure according to the first embodiment of the present invention. The heat transfer tube 2 has a flat shape having a substantially oval cross section perpendicular to the longitudinal direction, and an outer shape is constituted by an arcuate R portion 2c having a short side and a flat portion 2d having a long side. The heat transfer tube 2 is a multi-hole tube, and the use of the multi-hole tube structure increases the contact area between the inner surface of the heat transfer tube and the refrigerant, thereby improving the heat exchange efficiency. The material of the heat transfer tube 2 is mainly aluminum or an aluminum alloy, and is formed by an extrusion molding or pultrusion processing method. When the corrosion progresses in the heat transfer tube 2 having a flat cross section, pitting corrosion occurs. A sacrificial anode layer is preferably formed on the outer surface of the heat transfer tube 2 by, for example, zinc spraying in order to prevent leakage of refrigerant in the tube due to pitting corrosion.

The flat joint 3 has an insertion port 3x of the heat transfer tube 2 and an insertion port 3y of the circular tube 4, and functions as a joint for connecting the heat transfer tube 2 having a flat cross section and the circular tube 4 having a circular cross section. To do. When connecting a heat transfer tube with a flat shape to a distributor or header, the heat exchanger needs to be converted to a circular tube once in order to improve the flexibility of piping and save space in the mounting space. There is. Since the circular tube 4 has excellent workability such as bending in an arbitrary direction and pipe expansion at the end of the tube, and has an axially symmetric cross section, there is an advantage that the mounting space can be used efficiently. The flat joint 3 is composed of a joint member 3A and a joint member 3B having the same shape. Each joint member has a structure in which a flat joint is divided in the minor axis direction, and two flat members having the same shape are combined to form the flat joint 3. An escape portion 3g that prevents brazing of the brazing material into the in-tube flow path is formed in the back of the insertion port 3x of the heat transfer tube 2. The relief portion 3g of the flat joint 3 has a larger bulge than the insertion port 3x.

  The flat joint 3 has a first fitting portion 7a, a flat portion 7b, and a second fitting portion 7c on both sides of the end portion in the flat direction. The heat transfer tube 2 is fixed to the first fitting portion 7a. The circular tube 4 is fixed to the second fitting portion 7c. The joint member 3A and the joint member 3B are fixed to each other by fitting claws, and the heat transfer tube 2 and the circular tube 4 sandwiched therebetween are also fixed at the same time. After fixing with a flat joint, by heating, the joint members, and the joint member and the heat transfer tube, the joint member and the circular tube are brazed, and conversion from a flat shape to a circular shape without leakage of refrigerant passing through the pipe A joint is formed.

  FIG. 3 is an exploded perspective view showing the joint structure according to the first embodiment of the present invention. The heat transfer tube 2 has a number of partition walls 2a, and the inside is divided into a plurality of in-tube flow paths 2b. The material of the flat joint 3 is a clad material of an aluminum alloy, and the surface to be combined, that is, the inner surface of the joint, is an aluminum alloy having a melting point lower than that of the core material. It is brazed to the tube. The outer surfaces of the joints (joint member 3A and joint member 3B) are made of an aluminum alloy containing a large amount of zinc, and a sacrificial anode layer is formed to provide corrosion resistance. Alternatively, an aluminum alloy bare material may be used as a joint material, and a brazing material such as a paste brazing or a rod-shaped brazing may be supplied after assembling the heat transfer tube and the circular tube. The zinc on the outer surface may also be subjected to zinc spraying in a subsequent process without using a clad material.

  Since the flat joint member is formed by press working and uses two members having the same shape and the same specifications, the number of types produced is one and the productivity is excellent. In terminal processing of a circular tube material or deep drawing processing from a plate-shaped material, the deformation amount applied to the raw material increases as the long axis dimension of the flat shape increases with respect to the short axis dimension. When the material exceeds the material elongation, the material breaks, and the material cannot be processed into a predetermined shape. Even if it can be processed, the thickness may decrease and the pressure resistance performance may not be satisfied. In the present invention, since the flat joint 3 has a two-part structure, the amount of deformation applied to one piece is small, and the amount of thinning is small, so that a sufficient thickness can be ensured even after processing. The joint member 3A and the joint member 3B include a first claw receiving portion 3a, a flat portion 3b, a second claw receiving portion 3c, a first fitting claw 3d, a flat portion 3e, a second fitting claw 3f, a relief portion 3g, and a half. It has a split heat transfer tube insertion port 3j and a half-circular tube insertion port 3k.

  The first claw receiving portion 3a of the joint member 3A engages with the first fitting claw 3d of the joint member 3B. The flat part 3b of the joint member 3A faces the flat part 3e of the joint member 3B. The second claw receiving portion 3c of the joint member 3A engages with the second fitting claw 3f of the joint member 3B. The first fitting claw 3d of the joint member 3A engages with the first claw receiving portion 3a of the joint member 3B. The flat part 3e of the joint member 3A faces the flat part 3b of the joint member 3B. The second fitting claw 3f of the joint member 3A engages with the second claw receiving portion 3c of the joint member 3B. The positions of the second claw receiving portion 3c and the second fitting claw 3f may be reversed. The half heat transfer tube insertion port 3j of the joint member 3A and the half heat transfer tube insertion port 3j of the joint member 3B are combined to form the insertion port 3x. The half-circular tube insertion port 3k of the joint member 3A and the half-circular tube insertion port 3k of the joint member 3B are combined to form the insertion port 3y.

  Based on FIG. 4 (FIGS. 4A to 4C), the structure of the flat joint according to Embodiment 1 of the present invention will be described in more detail. FIG. 4A shows a front view and a plan view of the connection location. FIG. 4B shows a cross-sectional view relating to a cross-section AA of the connection portion between the heat transfer tube 2 and the flat joint 3 and a partial detail view thereof. FIG. 4C shows a cross-sectional view relating to a cross-section BB of a connection portion between the heat transfer tube 2 and the flat joint 3 and a partial detail view thereof. The heat transfer tube 2 having a flat cross section has a partition wall 2a in the tube and is divided into a plurality of in-tube flow paths 2b. This in-pipe channel 2b tends to be miniaturized for performance improvement, and brazing material permeates into the in-pipe channel and brazing occurs. In the present invention, the brazing material is transmitted through the end surface of the heat transfer tube and penetrates into the in-tube flow path as a structure in which the escape portion 3g is provided around the entire end surface of the heat transfer tube between the end surface of the heat transfer tube 2 and the inner wall of the joint. This is to prevent this.

  When integrally molding without dividing the joint having a flat shape, it is difficult to form the relief portion 3g in the present invention due to the restriction of the molding direction in the end processing of the circular pipe and the deep drawing processing of the plate material. By making the joint into a split structure, the escape portion 3g over the entire circumference of the end face of the heat transfer tube can be formed. With this structure, it is possible to prevent occurrence of brazing of the pipe flow path, and it is possible to realize brazing of the joint without deteriorating the intended heat transfer performance. Even when the dimensional ratio of the major axis side to the minor axis side of the flat shape is increased, the amount of deformation applied to the raw plate material is small because of the two-part structure. The workability from the plate material is improved, and a sufficient thickness of the joint can be secured, so that a predetermined pressure resistance performance can be secured.

  Further, the heat transfer tube having a flat shape has a structure that does not contact the inner wall of the joint over the entire circumference of the tube end. It is possible to prevent brazing filler metal from passing through the inner wall of the joint and penetrating into the pipe flow path of the heat transfer pipe having a flat shape, and to prevent deterioration in heat transfer performance due to the blockage of the pipe flow path. Is possible. This heat transfer tube end and the inner wall of the joint do not come into contact with each other, and it is difficult to form by a well-known joint processing method, such as a tube end end processing of a circular tube or deep drawing from a plate-like material. It is. With the two-part structure according to the present invention, the shape can be easily formed by pressing the plate material.

Embodiment 2. FIG.
FIG. 5 is an exploded perspective view showing a joint structure according to Embodiment 2 of the present invention. The heat transfer tube 2 has a flat cross section. The flat joint 3 is a joint that connects the heat transfer tube 2 and the circular tube 4, and adopts a divided structure as in the first embodiment. Further, in the flat joint according to the second embodiment of the present invention, the mounted heat exchanger has the configuration described in the first embodiment. The flat joint 3 combines two parts (a joint member 3A and a joint member 3B) having the same shape and the same specification to form one joint shape. The flat joint 3 according to the second embodiment has a relief portion 3g, a female dowel 3h, and a male dowel 3i. The female dowel 3h protrudes toward the inside of the pipe (the refrigerant side). The female dowel 3h protrudes toward the outside of the tube. The female dowel 3h of the joint member 3A is formed at a position to be fitted with the male dowel 3i of the joint member 3B. The male dowel 3i of the joint member 3A is formed at a position to be fitted with the female dowel 3h of the joint member 3B.

  As temporary fixing until heating and brazing, the concave and convex portions of the female dowel 3h and the male dowel 3i are fitted to integrate the joint member 3A and the joint member 3B. There is no need to form a fitting structure outside the joint region, and the joint itself can be downsized. The female dowel 3h and the male dowel 3i are punched and formed at a depth of about half the plate thickness by press working, and the convex shape on one side is fitted into the concave shape on the other side, and the joint member 3A is crimped. And the joint member 3B is fixed. The female dowel 3h and the male dowel 3i are disposed in the vicinity of the insertion port 3x of the heat transfer tube 2 having a flat cross section and the insertion port 3y of the circular tube 4, and are provided in at least four or more places.

  Also in the present embodiment, the flat joint 3 is formed with a relief portion 3g that swells from the insertion port 3x over the entire circumference of the heat transfer tube end face, as in the first embodiment. The flat joint 3 has a structure that prevents the brazing material from being transmitted from the end surface of the heat transfer tube and penetrating into the flow path in the tube, thereby preventing the occurrence of brazing. Even when the dimensional ratio of the major axis side to the minor axis side of the flat shape is increased, the amount of deformation applied to the raw plate-like material is small because of the two-part structure. Since the workability with respect to the plate material is improved, it is possible to secure a sufficient thickness of the joint and to secure a predetermined pressure resistance performance.

  That is, the flat joint according to the present embodiment has a structure in which a flat heat transfer tube does not contact the inner wall of the joint over the entire circumference of the pipe end. By providing the escape portion 3g, the brazing material is connected from the inner wall of the joint, and it is possible to prevent the wax from penetrating into the pipe flow path of the heat transfer pipe having a flat shape, and by closing the pipe flow path, It is possible to prevent a decrease in heat transfer performance. This heat transfer tube end and the inner wall of the joint do not come into contact with each other, and it is difficult to form by a well-known joint processing method, such as a tube end end processing of a circular tube or deep drawing from a plate-like material. It is. With the two-part structure in the present invention, the shape can be easily formed by pressing the plate material.

Embodiment 3 FIG.
FIG. 6 is an assembled perspective view showing a joint structure according to Embodiment 3 of the present invention. This is a structure in which heat transfer tubes having a flat cross section are connected to each other through a folded path, and includes a flat joint 3 and a U-bend tube 5 having a divided structure. The U-bend tube 5 is a circular tube 4 bent from the middle into a U-shape. The flat joint 3 composed of the joint member 3A and the joint member 3B includes an insertion port 3x of the heat transfer tube 2 and an insertion port 3y of the circular tube 4. Similarly, the flat joint 3 composed of the joint member 3C and the joint member 3D includes an insertion port 3x of the heat transfer tube 2 and an insertion port 3y of the circular tube 4. The U-bend pipe 5 is inserted into an insertion port 3y composed of the joint member 3A and the joint member 3B and an insertion port 3y composed of the joint member 3C and the joint member 3D. As described in the first and second embodiments, the joint portion has a divided structure, and the connecting portion with the heat transfer tube 2 having a flat cross section is provided with the escape portion 3g, so that the brazing material is connected to the in-tube flow path. It has a shape that prevents penetration.

  In order to obtain a hairpin shape at a predetermined fixed pitch when bending a heat transfer tube having a flat cross section into a long axis direction without using a joint, the longer the long axis of the flat shape, the longer the long axis. The elongation on the outside of the bending increases, leading to breakage. In addition, the amount of compression inside the bend also increases, buckling occurs, and it becomes impossible to form the required folded flow path. By using the flat joint according to the present invention, it is possible to form a hairpin-shaped folded flow path with a narrow pitch even if the major axis dimension of the flat shape is enlarged. Even when the dimensional ratio of the major axis side to the minor axis side of the flat shape is increased, the amount of deformation applied to the raw plate-like material is small because of the two-part structure. The workability from the plate material is improved, and a sufficient thickness of the joint can be secured, so that a predetermined pressure resistance performance can be secured.

  That is, the flat joint according to the present embodiment has a structure in which a flat heat transfer tube does not contact the inner wall of the joint over the entire circumference of the pipe end. By providing the escape portion 3g, the brazing material is connected from the inner wall of the joint, and it is possible to prevent the wax from penetrating into the pipe flow path of the heat transfer pipe having a flat shape, and by closing the pipe flow path, It is possible to prevent a decrease in heat transfer performance. This heat transfer tube end and the inner wall of the joint do not come into contact with each other, and it is difficult to form by a well-known joint processing method, such as a tube end end processing of a circular tube or deep drawing from a plate-like material. It is. With the two-part structure in the present invention, the shape can be easily formed by pressing the plate material.

Embodiment 4 FIG.
Based on FIG. 7 (FIG. 7A-FIG. 7C), the structure of the flat joint by Embodiment 4 of this invention is demonstrated in detail. FIG. 7A is a plan view showing a joint structure according to the present embodiment. At the place where the one side and the other side of the joint divided into two (the flat portion 7b) are joined, no significant gap is generated in the flat portion. On the other hand, a remarkable gap is generated in the second fitting portion 7c corresponding to the insertion port of the circular tube 4 (see FIG. 7B). Similarly, a significant gap is also generated in the first fitting portion 7a corresponding to the insertion port of the heat transfer tube 2 (see FIG. 7C). This is a shape that is surely generated from the shape of the press die at the place where the processing R generated when the plate-shaped material is pressed is combined. Since it is impossible to eliminate the processing R, it is conceivable that the brazing material does not permeate and brazing occurs because the gap space is larger in the mating portion than in other locations.

  In this invention, in the 1st fitting part 7a and the 2nd fitting part 7c, it has the shape which provided the 1st crushing part 12 and the 2nd crushing part 13, respectively. By forming a concave shape by a necking process or a knocking process in the press process, the process R on the side opposite to the plate thickness is reduced, and the gap space of the mating part is reduced. As a result, even with a small amount of brazing material, it becomes possible to fill the gaps in the mating portion and to prevent defective brazing. When a clad material with a brazing material layer is used, brazing can be performed without leakage at a low clad rate, and even when brazing material is supplied after the joint is assembled, the supply amount can be reduced. It becomes possible. The crushing part may be formed by press molding in the pre-process for assembling the two divided parts, or may be formed by sandwiching the two parts with a pliers-shaped jig tool. Good.

  That is, the flat joint according to the present embodiment has a structure in which the flat heat transfer tube does not contact the inner wall of the joint over the entire circumference of the pipe end. By providing the escape portion 3g, the brazing material is connected from the inner wall of the joint, and it is possible to prevent the wax from penetrating into the pipe flow path of the heat transfer pipe having a flat shape, and by closing the pipe flow path, It is possible to prevent a decrease in heat transfer performance. This heat transfer tube end and the inner wall of the joint do not come into contact with each other, and it is difficult to form by a well-known joint processing method, such as a tube end end processing of a circular tube or deep drawing from a plate-like material. It is. With the two-part structure in the present invention, the shape can be easily formed by pressing the plate material.

Embodiment 5. FIG.
FIG. 8 is an assembled perspective view showing a joint structure according to Embodiment 5 of the present invention. This is a structure in which heat transfer tubes having a flat cross section are connected to each other through a folded path, and is composed of a flat joint having a divided structure. Similar to the first to fourth embodiments, the joint portion has a divided structure, and a relief portion 3g is provided at a connection point with the heat transfer tube having a flat cross section to prevent penetration of the brazing material into the flow path in the tube. Have a shape to do. In the joint of the split structure, the folded flow path is included, and the productivity is improved by reducing the number of parts. Further, by reducing the number of connection points with the circular pipe, it is possible to prevent refrigerant leakage from the connection part, and quality reliability is improved. The joint member 3A and the joint member 3B have two half heat transfer pipe insertion ports 3j and one half U-bend pipe portion 5a.

  As described in the first and second embodiments, the joint member 3A and the joint member 3B are fixed by claw fitting or dowel caulking and brazed by heating. When the path from the joint to the distributor and the header requires a complicated path with a three-dimensional shape, it is reasonable to bend the circular pipe and connect it to the joint. For example, if it is as simple as a two-dimensional folding path, by including a half U-bend pipe part 5a in each joint member, the number of parts can be reduced and the number of connection points can be reduced. Quality is improved. The flat joint 3 according to the present embodiment includes two insertion holes 3x for heat transfer tubes. The heat transfer tubes 2 are inserted into the respective insertion ports 3x. Relief portions 3g are formed at the back of each insertion port, and the two relief portions 3g are connected by half U-bend pipe portions 5a.

  In order to obtain a hairpin shape at a predetermined fixed pitch when bending a heat transfer tube having a flat cross section into a long axis direction without using a joint, the longer the long axis of the flat shape, the longer the long axis. The elongation on the outside of the bending increases, leading to breakage. In addition, the amount of compression inside the bend also increases, buckling occurs, and it becomes impossible to form the required folded flow path. By using the flat joint according to the present invention, it is possible to form a hairpin-shaped folded flow path with a narrow pitch even if the major axis dimension of the flat shape is enlarged. According to the present embodiment, even when the dimensional ratio on the long axis side to the flat axis on the short axis side is increased, the amount of deformation applied to the raw plate-like material is small because of the two-part structure. The workability from the plate material is improved, and a sufficient thickness of the joint can be secured, so that a predetermined pressure resistance performance can be secured.

  That is, the flat joint according to the present embodiment has a structure in which the flat heat transfer tube does not contact the inner wall of the joint over the entire circumference of the pipe end. By providing the escape portion 3g, the brazing material is connected from the inner wall of the joint, and it is possible to prevent the wax from penetrating into the pipe flow path of the heat transfer pipe having a flat shape, and by closing the pipe flow path, It is possible to prevent a decrease in heat transfer performance. This heat transfer tube end and the inner wall of the joint do not come into contact with each other, and it is difficult to form by a well-known joint processing method, such as a tube end end processing of a circular tube or deep drawing from a plate-like material. It is. With the two-part structure in the present invention, the shape can be easily formed by pressing the plate material.

  It should be noted that the present invention can be freely combined with each other within the scope of the invention, and each embodiment can be appropriately modified or omitted.

DESCRIPTION OF SYMBOLS 1 Fin, 2 Heat transfer tube, 2a Bulkhead, 2b Pipe flow path, 2c Arc-shaped R part, 2d Plane part, 3 flat joint, 3A joint member, 3B joint member, 3C joint member, 3D joint member, 3a 1st claw Receiving portion, 3b flat portion, 3c second claw receiving portion, 3d first fitting claw, 3e flat portion, 3f second fitting claw, 3g relief portion, 3h female dowel, 3i male dowel, 3j half heat transfer tube insertion 3k insertion port, 3x insertion port, 3y insertion port, 4 circular tube, 5 U bend tube, 5a half U bend tube portion, 6 refrigerant, 7a first fitting portion, 7b flat portion, 7c 2nd fitting part, 12 1st crushing part, 13 2nd crushing part, 100 heat exchanger, R processing

Claims (9)

A circular tube with a cylindrical cross-section;
A heat transfer tube in which the flow path of the refrigerant is divided by a plurality of partition walls;
A plurality of fins joined to the heat transfer tube;
A flat joint having an insertion port of the circular tube and an insertion port of the heat transfer tube, and a relief portion formed at the back of the insertion port of the heat transfer tube;
The flat shape joint, Ri Na are joined two joint members having the same shape,
The circular tube insertion port, the heat transfer tube insertion port, and the relief portion are formed by combining a half-circular tube insertion port, a half heat transfer tube insertion port, and a half-shaped relief portion, respectively. A heat exchanger characterized by that.   2. The heat exchanger according to claim 1, wherein the joint member includes a first fitting claw, a second fitting claw, a first claw receiving portion, and a second claw receiving portion.   The heat exchanger according to claim 1, wherein the joint member includes a first male dowel, a second male dowel, a first female dowel, and a second female dowel.   The heat exchanger according to claim 1, wherein the circular tube is bent in a U shape from the middle.   4. The heat exchanger according to claim 2, wherein the flat joint has a crushing portion formed around an insertion port of the circular tube and an insertion port of the heat transfer tube. 5. A heat transfer tube in which the flow path of the refrigerant is divided by a plurality of partition walls;
A plurality of fins joined to the heat transfer tube;
A flat joint having two insertion holes for the heat transfer tubes, each of which has an escape portion formed at the back, and the two insertion ports are connected by a half U-bend tube portion. And comprising
The flat shape joint, Ri Na are joined two joint members having the same shape,
Spigot and the relief portion of the heat transfer tubes, respectively, the relief portion of the half heat transfer tube insertion holes and the halved A heat exchanger, characterized that you have been together in formation. The heat exchanger according to claim 1 or 6, wherein the relief portion of the flat joint has a larger bulge than the insertion port of the heat transfer tube. The first fitting claw and the second fitting claw are arranged on one side of the joint member,
The heat exchanger according to claim 2, wherein the first claw receiving portion and the second claw receiving portion are disposed on the other side of the joint member. The joint member has a first flat surface provided on one side of the center line and a second flat surface provided on the other side of the center line;
The first male dowel and the second male dowel are disposed on a first flat surface of the joint member;
The heat exchanger according to claim 3, wherein the first female dowel and the second female dowel are disposed on a second flat surface of the joint member.