US20190277569A1

US20190277569A1 - Heat exchanger and air-conditioner

Info

Publication number: US20190277569A1
Application number: US16/293,731
Authority: US
Inventors: Daiwa SATO; Shigeyuki Sasaki; Hiroshi Maita; Takeshi Endo
Original assignee: Hitachi Johnson Controls Air Conditioning Inc
Current assignee: Hitachi Johnson Controls Air Conditioning Inc
Priority date: 2018-03-12
Filing date: 2019-03-06
Publication date: 2019-09-12
Also published as: JP2019158215A; CN110260702A

Abstract

Provided is a heat exchanger which includes: a flat pipe as a heat transfer pipe in which refrigerant flows; and multiple fins having openings for inserting the flat pipe and arranged at a predetermined interval in a length direction of the flat pipe. At the flat pipe, multiple linear cutouts used for positioning the multiple fins are formed at the predetermined interval in the length direction of the flat pipe, and at least part of an edge of each opening contacts a corresponding one of the cutouts.

Description

CROSS-REFERENCE TO RELATED APPLICATION

This application claims the benefit of priority to Japanese Patent Application No. 2018-044511 filed with the Japan Patent Office on Mar. 12, 2018, the disclosures of all of which are hereby incorporated by reference in their entireties.

TECHNICAL FIELD

The present disclosure relates to a heat exchanger and an air-conditioner.

BACKGROUND ART

A parallel flow heat exchanger has been known as a heat exchanger used for, e.g., an air-conditioner. The parallel flow heat exchanger is configured to distribute refrigerant to multiple flat pipes through a header and to further cause the refrigerant to join together at another header through each flat pipe. A technique known as an example of the parallel flow heat exchanger is disclosed in Japanese Patent Application Publication No. 2011-043322 A.
That is, Japanese Patent Application Publication No. 2011-043322 A discloses the heat exchanger including multiple tubes having a flat sectional shape and configured such that fluid flows in the tubes and a fin joined to flat surfaces of the tubes. Note that the above-described fin includes louvers protruding from a plate surface of the fin.

SUMMARY OF THE INVENTION

In the technique described in Japanese Patent Application Publication No. 2011-043322 A, the louvers (cut-and-raised portions formed at the fin) protruding from the plate surface of the fin are provided. Thus, an interval between adjacent fins is held constant. However, there is a probability that the provided louvers result in a ventilation resistance increase. When the heat exchanger is used as an evaporator, condensed water formed on the fin adheres to the louvers. In some cases, the condensed water might be frozen and interfere with drainage. Considering such a probability, the above-described louvers may be designed small. However, microfabrication is necessary, and for this reason, it is difficult to form a shape as designed.
Note that one factor greatly influencing performance of the heat exchanger is a fin pitch as an interval between adjacent fins. For example, a relatively-shorter fin pitch results in a greater number of fins per unit length (i.e., a larger heat transfer area). As a result, a heat exchange efficiency is increased. However, ventilation resistance is increased on the other hand. This brings an increase in fan power consumption. A relatively-longer fin pitch results in smaller ventilation resistance. However, the number of fins per unit length is decreased on the other hand. This leads to lowering of the heat exchange efficiency. For both of the ventilation resistance and the heat exchange efficiency, it has been demanded that the fin pitch is accurately and easily set.
For these reasons, the present embodiment is intended to provide a heat exchanger and an air-conditioner configured so that a fin pitch can be accurately and easily set.
To address the above-described objective, the present disclosure is provided in which, at least one of a condenser or an evaporator includes: a flat pipe as a heat transfer pipe in which refrigerant flows and is in a flat shape as viewed in a longitudinal section; and multiple fins having openings for inserting the flat pipe and arranged at a predetermined interval in a length direction of the flat pipe. At the flat pipe, multiple linear cutouts used for positioning the multiple fins are formed at the predetermined interval in the length direction of the flat pipe, and at least part in the vicinity of an edge of each opening contacts a corresponding one of the cutouts.
According to the present disclosure, the heat exchanger and the air-conditioner configured so that the fin pitch can be accurately and easily set can be provided.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a configuration diagram including a refrigerant circuit of an air-conditioner including a heat exchanger according to a first embodiment of the present disclosure;

FIG. 2 is a perspective view of the heat exchanger according to the first embodiment of the present disclosure;

FIG. 3 is a partially-enlarged perspective view including a longitudinal section of the heat exchanger according to the first embodiment of the present disclosure;

FIG. 4 is a schematic longitudinal sectional view of one example of the method for forming cutouts at a flat pipe at the step of manufacturing the heat exchanger according to the first embodiment of the present disclosure;

FIG. 5 is a partially-enlarged perspective view before fin collars each contact cutouts, the partially-enlarged perspective view including a longitudinal section of a heat exchanger according to a second embodiment of the present disclosure;

FIG. 6 is a partially-enlarged perspective view when the fin collars each contact cutouts, the partially-enlarged perspective view including the longitudinal section of the heat exchanger according to the second embodiment of the present disclosure;

FIG. 7 is a partially-enlarged perspective view including a longitudinal section of a heat exchanger according to a third embodiment of the present disclosure;

FIG. 8A is a longitudinal sectional view of a variation of the present embodiment when fin collars are each pressed against first inclined surfaces of a flat pipe;

FIG. 8B is a longitudinal sectional view of the variation of the present embodiment when the fin collars are each pressed against planar portions of the flat pipe;

FIG. 8C is a longitudinal sectional view of the variation of the present embodiment when the fin collars each move over the planar portions;

FIG. 9 is a perspective view of a comparative example where cut-and-raised portions are provided at each fin instead of providing cutouts at a flat pipe; and

FIG. 10 is a partially-enlarged perspective view including the longitudinal section of the comparative example where the cut-and-raised portions are provided at each fin instead of providing the cutouts at the flat pipe.

DETAILED DESCRIPTION

First Embodiment

FIG. 1 is a configuration diagram of a refrigerant circuit Q of an air-conditioner W. Note that solid arrows of FIG. 1 indicate a refrigerant flow in cooling operation. On the other hand, dashed arrows of FIG. 1 indicate a refrigerant flow in heating operation. The air-conditioner W is equipment configured to perform air-conditioning in such a manner that refrigerant circulates in a refrigeration cycle (a heat pump cycle). As illustrated in FIG. 1, the air-conditioner W includes a compressor 11, an outdoor heat exchanger 12 (a heat exchanger), an outdoor fan 13, an indoor heat exchanger 14 (a heat exchanger), an indoor fan 15, a throttle device 16 (an expansion valve), and a four-way valve 17.
In an example illustrated in FIG. 1, the compressor 11, the outdoor heat exchanger 12, the outdoor fan 13, the throttle device 16, and the four-way valve 17 are provided at an outdoor unit Wo. On the other hand, the indoor heat exchanger 14 and the indoor fan 15 are provided at an indoor unit Wi. The outdoor unit Wo and the indoor unit Wi are connected to each other through a blocking valve V and connection pipes k1, k2 forming part of the later-described refrigerant circuit Q.
The compressor 11 is equipment configured to compress gaseous refrigerant. Examples of the frequently-used compressor 11 include a rotary compressor and a reciprocating compressor. Note that the examples of the compressor 11 are not limited to above.
The outdoor heat exchanger 12 is a heat exchanger configured to exchange heat between refrigerant flowing in a heat transfer pipe of the outdoor heat exchanger 12 and external air sent from the outdoor fan 13. The outdoor fan 13 is a fan configured to send the external air to the outdoor heat exchanger 12. The outdoor fan 13 includes an outdoor fan motor 13 a as a drive source.
The indoor heat exchanger 14 is a heat exchanger configured to exchange heat between refrigerant flowing in a heat transfer pipe of the indoor heat exchanger 14 and indoor air (air in an air-conditioning target space) sent from the indoor fan 15. The indoor fan 15 is a fan configured to send the indoor air to the indoor heat exchanger 14. The indoor fan 15 includes an indoor fan motor 15 a as a drive source.
The throttle device 16 is an expansion valve configured to depressurize refrigerant condensed by a “condenser” (one of the outdoor heat exchanger 12 or the indoor heat exchanger 14). Note that the refrigerant depressurized by the throttle device 16 is guided to an “evaporator” (the other one of the outdoor heat exchanger 12 or the indoor heat exchanger 14).
The four-way valve 17 is a valve configured to switch a refrigerant flow path according to an operation mode of the air-conditioner W. For example, in the cooling operation (see the solid arrows of FIG. 1), refrigerant circulates sequentially in the compressor 11, the outdoor heat exchanger 12 (the condenser), the throttle device 16, and the indoor heat exchanger 14 (the evaporator) in the refrigeration cycle.
More specifically, in the cooling operation, high-temperature high-pressure gas refrigerant discharged from the compressor 11 is guided to the outdoor heat exchanger 12 through the four-way valve 17. Then, the outdoor heat exchanger 12 releases heat to the external air. Accordingly, the refrigerant is condensed into high-pressure liquid refrigerant. The liquid refrigerant turns into low-temperature low-pressure gas-liquid two-phase refrigerant by depressurization by the throttle device 16. The gas-liquid two-phase refrigerant is guided to the indoor heat exchanger 14 through the connection pipe k1. Further, the refrigerant is evaporated by absorbing heat from the indoor air. In this manner, the indoor air is cooled. The gas refrigerant evaporated in the indoor heat exchanger 14 returns to a suction side of the compressor 11 sequentially through the connection pipe k2 and the four-way valve 17.
On the other hand, in the heating operation, the refrigerant flow path is switched by the four-way valve 17. That is, in the heating operation (see the dashed arrows of FIG. 1), refrigerant circulates sequentially in the compressor 11, the indoor heat exchanger 14 (the condenser), the throttle device 16, and the outdoor heat exchanger 12 (the evaporator) in the refrigeration cycle. That is, the direction of refrigerant flowing in the outdoor heat exchanger 12 and the indoor heat exchanger 14 is reversed between the cooling operation and the heating operation.
Note that equipment such as the compressor 11, the outdoor fan motor 13 a, the indoor fan motor 15 a, and the throttle device 16 is driven based on a command from a not-shown control device. Next, configurations of the outdoor heat exchanger 12 and the indoor heat exchanger 14 will be described with reference to a parallel flow heat exchanger as an example. Note that the outdoor heat exchanger 12 and the indoor heat exchanger 14 will be collectively referred to as a “heat exchanger K” (see FIG. 2).
FIG. 2 is a perspective view of the heat exchanger K according to the present embodiment. The heat exchanger K illustrated in FIG. 2 is the parallel flow heat exchanger as described above. The heat exchanger K includes headers 1, 2, multiple flat pipes 3, and many fins 4. The header 1, 2 is a member configured to distribute refrigerant flowing into the header 1, 2 oneself to each flat pipe 3 or cause refrigerant flowing out of each flat pipe 3 to join together. The outer shape of the header 1, 2 is an elongated circular columnar shape.
For example, as indicated by an arrow of FIG. 2, when refrigerant flows into one header 1, the refrigerant is distributed from the header 1 to each flat pipe 3. Further, refrigerant flowing out of each flat pipe 3 joins together at the other header 2.
The flat pipe 3 is a heat transfer pipe in which refrigerant flows. The flat pipe 3 is in a flat shape as viewed in a longitudinal section. One end of each flat pipe 3 is connected to the header 1. The other end of each flat pipe 3 is connected to another header 2. Refrigerant flows through multiple holes h (see FIG. 3) provided side by side in the flat pipe 3. That is, refrigerant distributed to each flat pipe 3 through the header 1 flows through each hole h in such a flat pipe 3, and then, is guided to another header 2.
The multiple fins 4 are thin metal plates for ensuring a heat transfer area between refrigerant and air. In the example illustrated in FIG. 2, plate fins having elongated rectangular plate surfaces are used as the fins 4. Each fin 4 is arranged such that the plate surfaces thereof are parallel to each other and an interval (referred to as a fin pitch P: see FIG. 3) between adjacent ones of the fins is a predetermined interval.
The multiple fins 4 include openings 41 for attaching (inserting) the flat pipes 3 laterally (from a leeward side). In the example illustrated in FIG. 2, the multiple openings 41 are provided at equal intervals in a height direction of the heat exchanger K of FIG. 2 on one-to-one correspondence with the multiple flat pipes 3. The opening 41 is formed in such a manner that the fin 4 is cut out in a U-shape such that the opening opens to the leeward side in an air flow. The opening 41 has a fin collar 41 a (see FIG. 3) formed at an edge portion of the opening 41.
Note that a flow direction of air sent from the fan (e.g., in a case where the heat exchanger K is the outdoor heat exchanger 12, the outdoor fan 13: see FIG. 1) and a flow direction of refrigerant in the flat pipe 3 are perpendicular to each other. Moreover, the plate surface of each fin 4 is parallel to the air flow direction. Thus, ventilation resistance can be reduced while heat exchange between refrigerant and air can be promoted.
FIG. 3 is a partially-enlarged perspective view including a longitudinal section of the heat exchanger K. Each fin collar 41 a illustrated in FIG. 3 is a member for ensuring a contact area between the flat pipe 3 and the fin 4. As described above, the fin collar 41 a is provided at the edge portion of the U-shaped opening 41 (see FIG. 2). The fin collar 41 a is curved to one end side (the right side in the plane of paper of FIG. 3) in a length direction of the flat pipe 3.
At the flat pipe 3, multiple linear cutouts 31 used for positioning the multiple fins 4 are formed at predetermined intervals in the length direction of the flat pipe 3. Note that the above-described “predetermined interval” has a length equal to the fin pitch P as the interval between adjacent ones of the fins 4. Moreover, the “linear” cutout 31 means that each ridge line (e.g., ridge lines of a first inclined surface 31 a and a second inclined surface 31 b as described later) defining a V-shaped cutout as viewed in the longitudinal section of the flat pipe 3 illustrated in FIG. 3 is in a linear shape.
The ridge lines are parallel to each other, and in an example illustrated in FIG. 3, the cutouts 31 extend in a direction (a direction parallel to the air flow direction) perpendicular to the length direction of the flat pipe 3. Moreover, a planar portion 32 having a predetermined thickness is, in the length direction of the flat pipe 3, present between adjacent ones of the cutouts 31. Plate surfaces of the planar portions 32 on upper and lower sides of the flat pipe 3 are parallel to each other.
The cutout 31 in the V-shape as viewed in the longitudinal section includes the first inclined surface 31 a and the second inclined surface 31 b as two inclined surfaces defining the V-shape. The first inclined surface 31 a is inclined such that the depth of the cutout increases toward one end side (the right side in the plane of paper of FIG. 3) in the length direction of the flat pipe 3. The inclination angle θa of the first inclined surface 31 a with respect to the length direction of the flat pipe 3 is set as necessary so that a slight clearance can be formed between the fin collar 41 a and the first inclined surface 31 a. With this configuration, a brazing material Z can be applied to the clearance at the step of manufacturing the heat exchanger K.
The second inclined surface 31 b is inclined such that the depth of the cutout decreases toward one end side (the right side in the plane of paper of FIG. 3) in the length direction of the flat pipe 3. Note that as illustrated in FIG. 3, the second inclined surface 31 b also includes an inclined surface standing substantially perpendicularly to the length direction of the flat pipe 3.
The inclination angle θb of the second inclined surface 31 b with respect to the length direction of the flat pipe 3 is greater than the inclination angle θa of the first inclined surface 31 a. The V-shaped cutouts 31 each including the first inclined surfaces 31 a and the second inclined surfaces 31 b as described above are formed at predetermined intervals each equal to the fin pitches P. Note that cutouts 31 similar to those at an upper surface of the flat pipe 3 are also formed at a lower surface of the flat pipe 3.
As described above, the fin collar 41 a is curved to one end side (the right side in the plane of paper of FIG. 3) in the length direction of the flat pipe 3. An edge portion of the fin collar 41 a contacts the vicinity of a lower end of the second inclined surface 31 b of the cutout 31. In other words, at least part of the edge of the fin collar 41 a contacts, as viewed in the longitudinal section of the flat pipe 3, the bottom of the cutout 31 in a saw blade shape.
FIG. 4 is a schematic longitudinal sectional view of one example of the method for forming the cutouts 31 at the flat pipe 3 at the step of manufacturing the heat exchanger. As illustrated in FIG. 4, a pair of tools E1, E2 (e.g., a rolling machine) in a gear shape as viewed in the longitudinal section may be used to form the cutouts 31 at the flat pipe 3. That is, the high-temperature flat pipe 3 in a deformable state is sandwiched by the tools E1, E2 from both of the upper and lower sides. Then, these tools E1, E2 rotate to form the cutouts on both of the upper and lower sides of the flat pipe 3. Note that the method for forming the cutouts 31 is not limited to the method illustrated in FIG. 4.
Then, the flat pipe 3 is attached in the horizontal direction into the U-shaped openings 41 of the fins 4. In this manner, the fin collars 41 a (see FIG. 3) are each attached into the cutouts 31 of the flat pipe 3. More specifically, the fins 4 are each brazed to the cutouts 31 in a state in which the edges of the fin collars 41 a each contact the vicinity of the lower ends of the second inclined surfaces 31 b.
Note that in a state in which the fin collars 41 a illustrated in FIG. 3 are not elastically deformed, an opening distance of the opening 41 (see FIG. 2) in an upper-to-lower direction may be designed smaller than a distance between the bottoms of the upper and lower cutouts 31 in a pair. With this configuration, when the fin collars 41 a are each attached in the horizontal direction into the cutouts 31, the fin collars 41 a are elastically deformed while being slightly pushed open in the upper-to-lower direction. In this manner, the fin collars 41 a are each pressed against the cutouts 31.
By force accompanied by elastic deformation of the fin collars 41 a , the edge portions of the fin collars 41 a are guided to the second inclined surfaces 31 b to slide down on the first inclined surfaces 31 a. Further, when the edge portions of the fin collars 41 a each come into contact with the second inclined surfaces 31 b, movement of these edge portions is restricted. In this manner, the relative positions of the flat pipe 3 and the fins 4 in the length direction of the flat pipe 3 are fixed.
When the flat pipes 3 and the fins 4 after assembly enter a high-temperature sintering furnace (not shown), the brazing material Z on the surfaces of the fins 4 is melted. Then, the brazing material Z enters each clearance between the cutout 31 and the fin collar 41 a (see FIG. 3). In this manner, the flat pipes 3 and the fins 4 are fixed to each other with the fin collars 41 a each contacting the cutouts 31.

According to the first embodiment, the cutouts 31 are formed at the predetermined intervals each equal to the fin pitches P in the length direction of the flat pipe 3 (see FIG. 3). As described above, these cutouts 31 are easily formed using the pair of tools E1, E2 (see FIG. 4) in the gear shape as viewed in the longitudinal section. Moreover, the fin collars 41 a are each placed in the cutouts 31, and therefore, the fins 4 can be fixed to the flat pipes 3 at the predetermined fin pitches P. As described above, the first embodiment can provide the air-conditioner W and the heat exchanger K configured so that the fin pitch P can be accurately and easily set.
FIG. 9 is a perspective view of a comparative example where cut-and-raised portions 42 are provided at each fin 4G instead of providing cutouts at a flat pipe 3G In the comparative example illustrated in FIG. 9, the cut-and-raised portions 42 are provided in such a manner that part of each fin 4G is cut and raised to one side (the right side in the plane of paper of FIG. 9) of a plate surface. Generally, hundreds or thousands of fins 4G or more are used. Thus, even a slight error in the height of the cut-and-raised portion 42 greatly influences heat exchange performance
FIG. 10 is a partially-enlarged perspective view including a longitudinal section of the above-described comparative example. As illustrated in FIG. 10, the flat pipe 3G and the fin collars 41 a are fixed to each other with the brazing material Z in each clearance between the flat pipe 3G and the fin collar 41 a. Moreover, the predetermined fin pitch P is held by the cut-and-raised portions 42 (see FIG. 9) provided at the fins 4G
As described above, when the cut-and-raised portions 42 are provided at the fins 4G, there is a probability that degradation of drainage and a ventilation resistance increase are caused. When the small cut-and-raised portions 42 are designed considering such a probability, microfabrication is necessary. For this reason, in some cases, the fins 4G cannot be processed as designed. As a result, there is a probability that an unignorable dimension error is caused.
Note that instead of providing the cut-and-raised portions 42, the height of the fin collar 41 a may be increased such that the fin collar 41 a contacts the adjacent fin 4G. However, in the case of forming the fin 4G by pressing, it is difficult to form the height of the fin collar 41 a equal to the fin pitch P, considering the bending angle, thickness and the like of the fin collar 41 a.
On the other hand, in the first embodiment, the cutouts 31 are provided at the flat pipe 3. Thus, as described above, the fin pitch P can be accurately and easily set. Moreover, additional cut-and-raised portions are not necessarily provided at the fins 4. Consequently, according to the first embodiment, improvement of heat exchange performance and reduction in a manufacturing cost in the heat exchanger K can be realized.

Second Embodiment

In a second embodiment, the shape of a cutout 31A of a flat pipe 3A (see FIG. 5) is different from the shape of the cutout 31 of the first embodiment. Moreover, the second embodiment is different from the first embodiment in that an opening distance L of an opening 41 (see FIG. 5) is relatively long and each fin collar 41 a is pressed against a first inclined surface 31 a. Note that other configurations are similar to those of the first embodiment. Thus, the configurations different from those of the first embodiment will be described below. Overlapping configuration description will be omitted.
FIG. 5 is a partially-enlarged perspective view in a state before each fin collar 41 a contacts the cutout 31A, the partially-enlarged perspective view including a longitudinal section of a heat exchanger KA according to the second embodiment. That is, in FIG. 5, fins 4A are not brazed in the middle of assembly with the flat pipe 3A. As in the first embodiment, the multiple linear cutouts 31A are formed at predetermined intervals each equal to fin pitches P on both of upper and lower sides of the flat pipe 3A in a flat shape as viewed in the longitudinal section.
The cutout 31A includes a first inclined surface 31 a, a second inclined surface 31 b, and a bottom surface 31 c. The inclination angles of the first inclined surface 31 a and the second inclined surface 31 b are similar to those of the first embodiment. The bottom surface 31 c is a bottom surface of the cutout 31A. The bottom surface 31 c is present between the first inclined surface 31 a and the second inclined surface 31 b.
The upper-to-lower thickness of a planar portion 32 present between adjacent ones of the cutouts 31A is defined herein as t1. Moreover, the opening distance of the opening 41 in a direction perpendicular to the plane of the planar portion 32 is defined as L. Further, a distance between the bottom surfaces 31 c of the cutouts 31A facing each other in the direction perpendicular to the plane of the planar portion 32 (between the upper and lower bottom surfaces 31 c) is defined as t2. The thickness t1, the opening distance L, and the distance t2 as described above are in a magnitude relationship represented by t1>L>t2.
FIG. 6 is a partially-enlarged perspective view when each fin collar 41 a contacts the cutout 31A, the partially-enlarged perspective view including the longitudinal section of the heat exchanger KA. As illustrated in FIG. 6, upper and lower edges of each fin collar 41 a contact the first inclined surface 31 a. In other words, at least part of the edge of the fin collar 41 a (the opening 41) contacts other surfaces (the first inclined surface 31 a) of the cutout 31A than the bottom surface 31 c.
As described above, the opening distance L is longer than the distance t2 between the bottom surfaces 31 c of the cutouts 31A. Thus, the edge of the fin collar 41 a is separated from the bottom of the cutout 31A. Instead, the fin collar 41 a is pressed against the first inclined surface 31 a having a relatively-small inclination angle.
With this configuration, when the flat pipe 3A is attached in the horizontal direction into the openings 41 of the fins 4A, there is almost no need to push open the openings 41 in an upper-to-lower direction and elastically deform the openings 41. Thus, the process of assembling the flat pipes 3A and the fins 4A together can be facilitated. Moreover, a moderate contact area between the fin collar 41 a and the first inclined surface 31 a of the flat pipe 3A can be ensured without the need for bending the fin collar 41 a much.

According to the second embodiment, the process of assembling the flat pipes 3A and the fins 4A together can be more easily performed than the first embodiment as described above. Moreover, the moderate contact area between the fin collar 41 a and the first inclined surface 31 a of the flat pipe 3A can be ensured.

Third Embodiment

A third embodiment is different from the first embodiment in that each cutout 31B formed at a flat pipe 3B (see FIG. 7) is curved as viewed in a longitudinal section and each fin collar 41Ba is also curved accordingly as viewed in the longitudinal section. Note that other configurations are similar to those of the first embodiment. Thus, the configurations different from those of the first embodiment will be described below. Overlapping configuration description will be omitted.
FIG. 7 is a partially-enlarged perspective view including a longitudinal section of a heat exchanger KB according to the third embodiment. As illustrated in FIG. 7, the multiple linear cutouts 31B are formed at predetermined intervals each equal to fin pitches P on both of upper and lower sides of the flat pipe 3B in a flat shape as viewed in the longitudinal section.
Each of the multiple cutouts 31B is in a curved shape as viewed in the longitudinal section. On the other hand, each opening 41B provided at a fin 4B has the fin collar 41Ba. The fin collar 41Ba is curved to roll back to one end side (the right side in the plane of paper of FIG. 7) in a length direction of the flat pipe 3B.
At least part of an edge of the fin collar 41Ba contacts the cutout 31B. That is, the fin collars 41Ba in a curved shape as viewed in the longitudinal section are pressed against the cutouts 31B to sandwich, from the upper and lower sides, the cutouts 31B in the curved shape as viewed in the longitudinal section. Even with this configuration, the fin pitch P can be accurately and easily set.

According to the third embodiment, the fin collar 41Ba in the curved shape as viewed in the longitudinal section is pressed against the curved cutout 31B. Thus, as in the first embodiment and the second embodiment, the fin pitch P can be accurately and easily set.

Fourth Embodiment

A fourth embodiment is different from the first embodiment in that different fin pitches P are set although not shown in the figure. Note that other configurations are similar to those of the first embodiment. Thus, the configurations different from those of the first embodiment will be described below. Overlapping configuration description will be omitted.
In the fourth embodiment, a flat pipe 3 is designed to have a relatively-short fin pitch P at a portion of a heat exchanger K (see FIG. 2) at which a wind speed tends to be high (the amount of heat to be exchanged tends to be great). On the other hand, the flat pipe 3 is designed to have a relatively-long fin pitch P at a portion of the heat exchanger K at which the wind speed tends to be low (the amount of heat to be exchanged tends to be small).
Note that distribution of the wind speed of air passing through the heat exchanger K (see FIG. 2) is not always uniform. That is, in some cases, there is variation in the wind speed. Moreover, the amount of heat to be exchanged also changes according to the wind speed. Thus, variation in the wind speed results in variation in the total exchanged heat amount of the heat exchanger K. Note that ventilation resistance of the heat exchanger K increases with respect to the wind speed in an exponential fashion. Thus, with the same flow rate of air passing through the heat exchanger K per unit area, the ventilation resistance is lowest in the case of uniform wind speed distribution.
For these reasons, in the fourth embodiment, the wind speed distribution of the heat exchanger K is predicted in advance by, e.g., simulation based not only on the structures of the heat exchanger K and a fan (e.g., an outdoor fan 13: see FIG. 1) but also on the structure of, e.g., a housing (not shown) configured to house these components. The fin pitch P is set as necessary at a design stage such that the wind speed distribution of the heat exchanger K is uniform.
As described above, the configuration employing the different intervals (i.e., the fin pitches P) between adjacent ones of cutouts 31 can reduce the ventilation resistance across the entirety of the heat exchanger K. Moreover, according to this configuration, the amount of heat to be exchanged in the heat exchanger K can be uniformized.

According to the fourth embodiment, the fin pitches P are set as necessary such that the wind speed distribution at the heat exchanger K is uniformized With this configuration, the ventilation resistance across the entirety of the heat exchanger K can be reduced, and therefore, heat exchange performance can be improved.
The fin pitches P are adjusted as necessary so that the amount of heat to be exchanged at the heat exchanger K can be uniformized. With this configuration, it is not necessary to newly adjust refrigerant flow rate distribution at the design stage to uniformize the amount of heat to be exchanged. Thus, a development period for the heat exchanger K can be shortened.
Note that in a comparative example where cut-and-raised portions 42 are provided at each fin 4G (see FIG. 9), if the different fin pitches P are provided to uniformize the wind speed distribution, it is necessary to prepare multiple types of fins 4G having different heights of the cut-and-raised portions 42. On the other hand, according to the fourth embodiment, the interval between the cutouts 31 of the flat pipe 3 may be adjusted as necessary according to the wind speed distribution. Thus, not only time and effort at the design stage can be saved, but also a manufacturing cost can be reduced.

Modifications

The heat exchanger K and the like according to the present disclosure have been described above in each embodiment. Note that the present embodiments are not limited to such description. Various changes can be made to the present embodiments. For example, each embodiment has described the configuration including the flat pipes 3 attached in the horizontal direction into the openings 41 (see FIG. 2) of the fins 4, but the present invention is not limited to above. For example, the opening 41 of the fin 4 is not necessarily the U-shaped cutout, and may be a flat insertion hole penetrating the fin 4 in a thickness direction thereof. A configuration including flat pipes 3 inserted into these insertion holes also provides advantageous effects similar to those of each embodiment. The method for assembling the flat pipes 3 as described above will be described with reference to FIGS. 8A, 8B, and 8C.
FIG. 8A is a longitudinal sectional view of the fin collars 41 a each pressed against the first inclined surfaces 31 a of the flat pipe 3. Note that the multiple fins 4 are, with a jig or the like (not shown), positioned in advance at the predetermined intervals with the fin collars 41 a being curved to one side (the right side in the plane of paper of FIG. 8A) in the direction of stacking the fins 4. In this state, the flat pipe 3 is slowly inserted to sequentially penetrate the opening 41 (the insertion hole) of each fin collar 41 a toward one side described above. Accordingly, the edge of each fin collar 41 a is pressed against the first inclined surface 31 a. Thus, the fin collar 41 a is elastically deformed, and is pushed open in the upper-to-lower direction. When the flat pipe 3 is further pushed in, a state illustrated in FIG. 8B is brought.
FIG. 8B is a longitudinal sectional view in a state in which each fin collar 41 a is pressed against the planar portion 32 of the flat pipe 3. As illustrated in FIG. 8B, the edge of the fin collar 41 a is pressed against the planar portion 32. As a result, the fin collar 41 a is elastically deformed, and is further pushed open in the upper-to-lower direction.
FIG. 8C is a longitudinal sectional view in a state in which each fin collar 41 a has moved over the planar portion 32. As illustrated in FIG. 8C, when the flat pipe 3 is further pushed in, the fin collar 41 a moves over the planar portion 32, and then, enters the adjacent cutout 31. In this manner, the flat pipe 3 is slowly pushed and inserted into the multiple fins 4 fixed with the jig or the like (not shown). Note that the above-described configuration is also applicable to the second to fourth embodiments.
Each embodiment has described the configuration including the cutouts 31 provided on both of the upper and lower sides of the flat pipe 3 (see FIG. 3). Note that the present embodiments are not limited to this configuration. For example, a configuration may be employed, in which the cutouts 31 are provided only on one of the upper or lower side of the flat pipe 3 and no cutouts 31 are provided on the other side. Alternatively, instead of both of the upper and lower sides of the flat pipe 3 (or in addition to both of the upper and lower sides), the cutouts 31 may be formed at a curved side surface of the flat pipe 3.
Each embodiment has described the configuration including the linear cutouts 31 having the inclined surfaces (the second inclined surfaces 31 b) perpendicular to the length direction of the flat pipe 3. Note that the present embodiments are not limited to this configuration. That is, all of the inclined surfaces of the linear cutouts 31 extending in the air flow direction may be inclined with respect to the length direction of the flat pipe 3. Alternatively, the cutouts 31 extending in the air flow direction may be locally provided at the flat pipe 3 instead of providing the cutouts 31 across the entirety of the flat pipe 3.
The embodiments may be combined as necessary. For example, the first embodiment and the second embodiment may be combined to form the following heat exchanger. That is, the edge of each fin collar 41 a may contact the second inclined surface 31 b of the cutout 31 on the upper side of the flat pipe 3 (the first embodiment: see FIG. 3), and on the other hand, the edge of each fin collar 41 a may contact the first inclined surface 31 a on the lower side of the flat pipe 3 (the second embodiment: see FIG. 6).
For example, the third embodiment and the fourth embodiment may be combined. That is, the cutouts 31B (see FIG. 7) of the configuration described in the third embodiment may be arranged at the different intervals described in the fourth embodiment. With this configuration, the amount of heat to be exchanged can be uniformized.
The first embodiment has described the example where the heat exchanger K having the configuration illustrated in FIG. 3 is applied to the outdoor heat exchanger 12 (see FIG. 1) and the indoor heat exchanger 14 (see FIG. 1) provided at the air-conditioner W. Note that the present embodiment is not limited to such an example. That is, the heat exchanger K having the configuration of the present embodiment may be applied to at least one of the outdoor heat exchanger 12 or the indoor heat exchanger 14 (at least one of the condenser or the evaporator).
The present disclosure describes each embodiment in detail for the sake of simplicity in description of each embodiment. Thus, the present embodiments are not limited to one including all of the configurations described above. Moreover, some of the configurations of each embodiment may be omitted, or may be replaced with other configurations. Further, other configurations may be added to the configurations of each embodiment. The present disclosure describes the mechanisms and configurations considered necessary for description. The present disclosure does not necessarily describe all mechanisms and configurations of the heat exchanger and the air-conditioner according to the present embodiments as a product. The foregoing detailed description has been presented for the purposes of illustration and description. Many modifications and variations are possible in light of the above teaching. It is not intended to be exhaustive or to limit the subject matter described herein to the precise form disclosed. Although the subject matter has been described in language specific to structural features and/or methodological acts, it is to be understood that the subject matter defined in the appended claims is not necessarily limited to the specific features or acts described above. Rather, the specific features and acts described above are disclosed as example forms of implementing the claims appended hereto.

Claims

What is claimed is:

1. A heat exchanger comprising:

a flat pipe as a heat transfer pipe in which refrigerant flows; and

multiple fins having openings for inserting the flat pipe and arranged at a predetermined interval in a length direction of the flat pipe,

wherein at the flat pipe, multiple linear cutouts used for positioning the multiple fins are formed at the predetermined interval in the length direction of the flat pipe, and

at least part of an edge of each opening contacts a corresponding one of the cutouts.

2. The heat exchanger according to claim 1, wherein

at least part of the edge of each opening contacts a bottom surface of a corresponding one of the cutouts.

3. The heat exchanger according to claim 2, wherein

each of the multiple cutouts is in a V-shape as viewed in a longitudinal section of the flat pipe,

two inclined surfaces defining the V-shape include a first inclined surface inclined such that a depth of each cutout increases toward one end side in the length direction of the flat pipe, and a second inclined surface having a greater inclination angle than an inclination angle of the first inclined surface with respect to the length direction of the flat pipe and inclined such that the depth of each cutout decreases toward the one end side,

each opening has a fin collar curved to the one end side, and

at least part of an edge of the fin collar contacts the bottom surface of the V-shaped cutout.

4. The heat exchanger according to claim 1, wherein

at least part of the edge of each opening contacts other surfaces of a corresponding one of the cutouts than the bottom surface.

5. The heat exchanger according to claim 4, wherein

a thickness tl of a planar portion present between adjacent ones of the cutouts in the length direction of the flat pipe, an opening distance L of each opening in a direction perpendicular to a plane of the planar portion, and a distance t2 between the bottom surfaces of opposing ones of the cutouts in the direction perpendicular to the plane of the planar portion are in a magnitude relationship represented by tl >L >t2.

6. The heat exchanger according to claim 5, wherein

each opening has a fin collar curved to the one end side, and

at least part of an edge of the fin collar contacts the first inclined surface.

7. The heat exchanger according to claim 1, wherein

each of the multiple cutouts is in a curved shape as viewed in a longitudinal section of the flat pipe,

each opening has a fin collar curved to roll back to one end side in the length direction of the flat pipe, and

at least part of an edge of the fin collar contacts a corresponding one of the cutouts.

8. The heat exchanger according to claim 1, wherein

at least one predetermined interval between adjacent ones of the cutouts is different from at least one of other predetermined intervals.

9. An air-conditioner comprising:

a refrigerant circuit in which refrigerant circulates sequentially in a compressor, an outdoor heat exchanger, an expansion valve, and an indoor heat exchanger,

wherein external air is sent to the outdoor heat exchanger by an outdoor fan,

air in an air-conditioning target space is sent to the indoor heat exchanger by an indoor fan, and

at least one of the outdoor heat exchanger or the indoor heat exchanger is the heat exchanger according to claim 1.

10. An air-conditioner comprising:

wherein external air is sent to the outdoor heat exchanger by an outdoor fan,

at least one of the outdoor heat exchanger or the indoor heat exchanger is the heat exchanger according to claim 2.

11. An air-conditioner comprising:

wherein external air is sent to the outdoor heat exchanger by an outdoor fan,

at least one of the outdoor heat exchanger or the indoor heat exchanger is the heat exchanger according to claim 3.

12. An air-conditioner comprising:

wherein external air is sent to the outdoor heat exchanger by an outdoor fan,

at least one of the outdoor heat exchanger or the indoor heat exchanger is the heat exchanger according to claim 4.

13. An air-conditioner comprising:

wherein external air is sent to the outdoor heat exchanger by an outdoor fan,

at least one of the outdoor heat exchanger or the indoor heat exchanger is the heat exchanger according to claim 5.

14. An air-conditioner comprising:

wherein external air is sent to the outdoor heat exchanger by an outdoor fan,

at least one of the outdoor heat exchanger or the indoor heat exchanger is the heat exchanger according to claim 6.

15. An air-conditioner comprising:

wherein external air is sent to the outdoor heat exchanger by an outdoor fan,

at least one of the outdoor heat exchanger or the indoor heat exchanger is the heat exchanger according to claim 7.

16. An air-conditioner comprising:

wherein external air is sent to the outdoor heat exchanger by an outdoor fan,

at least one of the outdoor heat exchanger or the indoor heat exchanger is the heat exchanger according to claim 8.