WO2020022443A1

WO2020022443A1 - Joint

Info

Publication number: WO2020022443A1
Application number: PCT/JP2019/029250
Authority: WO
Inventors: 俊吉岡; 祥志松本; 智己廣川
Original assignee: ダイキン工業株式会社
Priority date: 2018-07-25
Filing date: 2019-07-25
Publication date: 2020-01-30
Also published as: EP3828490A4; EP3828490A1; JP2021167676A; EP3828490B1

Abstract

For a joint connecting a multi-holed flat tube and a circular pipe, a problem may occur in which oil accumulates in the vicinity of a connection portion. In a refrigeration device that uses carbon dioxide as a refrigerant, for which oil is of high importance, this can be a significant problem. Provided is a joint (34) equipped with a first connection section (301) covering the outside of an end portion of a multi-holed flat tube (300), and a main body section (302) that continues from the first connection section (301), wherein the inner diameter (L₃₀₂) of the main body section (302) in the longitudinal direction is greater than the inner diameter (L₃₀₁) of the first connection section (301) in the longitudinal direction. The longitudinal direction is the thickness direction of the multi-holed flat tube (300) (thickness T, width W, W>T).

Description

Fitting

継手 A joint that connects a multi-hole flat tube and a circular tube, and allows carbon dioxide refrigerant to pass through.

冷凍 In a refrigeration system using carbon dioxide as the working fluid, a multi-well flat tube is used. On the other hand, when a multi-hole flat tube is used for a refrigerating apparatus, a multi-hole flat tube and a circular tube are sometimes connected, and a joint for connecting these is proposed (for example, Patent Document 1 (WO2014 / 199514)). )).).

継手 In the case of a joint that connects a multi-hole flat tube and a circular tube, there is a possibility that a problem that oil accumulates near the connection portion may occur. In a refrigeration system using carbon dioxide as a refrigerant, which has a high importance for oil, there is a possibility that this may be a major problem.

The joint according to the first aspect is a joint through which a CO ₂ refrigerant passes. The joint connects the multi-hole flat tube and the circular tube. The multi-hole flat tube has a thickness T and a width W. W> T. Here, the width of the multi-hole flat tube is a direction in which a plurality of holes are arranged. The thickness direction and the width direction of the multi-hole flat tube are defined as the longitudinal direction and the lateral direction of the joint, respectively. The joint includes a first connection portion and a main body. The first connecting portion covers the outside of the end of the multi-hole flat tube. The main body is continuous from the first connection. The inner diameter of the main body in the vertical direction is larger than the inner diameter of the first connection portion in the vertical direction.

In the joint according to the first aspect, the inner diameter in the longitudinal direction of the main body is larger than the inner diameter in the longitudinal direction of the first connecting portion, so that oil stays near the multi-hole flat tube on the inner peripheral surface of the first connecting portion. Hateful.

継手 The joint of the second aspect is the joint of the first aspect, in which the main body portion has a region in which the inner diameter in the vertical direction gradually increases as the distance from the first connection portion increases.

In the joint according to the second aspect, the main body portion gradually increases in inner diameter in the vertical direction as the distance from the first connection portion increases, so that the inner peripheral surface of the first connection portion is closer to the multi-hole flat tube. It is difficult for oil to stay.

継手 The joint of the third aspect is the joint of the first aspect or the second aspect, and further includes a second connection portion. The second connecting portion is continuous from the main body. The second connecting portion covers the outside of the end of the circular tube.

継手 A joint according to a fourth aspect is the joint according to the third aspect, wherein the first connection portion is formed by processing one end of a circular pipe.

継手 The joint according to the fourth aspect can be manufactured by processing a circular pipe, so that the manufacturing cost is low.

継手 The joint according to the fifth aspect is the joint according to the third aspect or the fourth aspect, wherein the thickness of the pipe of the joint is greater than the thickness of the circular pipe. Here, the circular pipe is intended to be a circular pipe to which the joint is connected.

継手 The joint according to the sixth aspect is the joint according to any one of the first to fifth aspects, and further includes a reinforcing portion. The reinforcing portion reinforces the strength of the joint.

継手 Since the joint of the sixth aspect uses the reinforcing portion, the strength is easily maintained even when the refrigerant pressure of the main body portion is high.

継手 The joint according to the seventh aspect is any one of the joints according to the first aspect to the sixth aspect, and is formed by bonding two or more members.

継手 The joint according to the eighth aspect is the joint according to the first aspect or the second aspect, wherein the main body is a part of a circular pipe.

継手 The joint according to the ninth aspect is the joint according to any one of the first to eighth aspects, and further has a flat portion that is continuous from the main body and does not form a refrigerant passage.

継手 A joint according to a tenth aspect is the joint according to the sixth aspect, wherein the reinforcing portion extends in the coolant flow path in the vertical direction.

継手 In the joint according to the tenth aspect, since the reinforcing portion is arranged to extend in the longitudinal direction in the refrigerant flow path, the expansion in the longitudinal direction inside the main body portion can be suppressed.

継手 A joint according to an eleventh aspect is the joint according to the sixth aspect, wherein the reinforcing portion is disposed outside the coolant flow path and in contact with the outer surface of the main body.

継手 The joint of the twelfth aspect is the joint of the sixth aspect, and further has a flat portion that is continuous from the main body and does not form a passage for the refrigerant. The reinforcing portion is disposed outside the coolant flow path in contact with the outer surface of the main body 302 and the surface of the flat portion.

熱 The heat exchanger of the present disclosure includes the joint according to any one of the first to twelfth aspects and a multi-hole flat tube. The multi-hole flat tube is connected to the joint.

空気 The air conditioner of the present disclosure is an air conditioner provided with a heat exchanger.

FIG. 2 is a refrigerant circuit diagram of the refrigeration apparatus 1 according to the first embodiment. The schematic perspective view of the outdoor unit 10 of 1st Embodiment. The schematic perspective view of some heat source side heat exchangers 4 of a 1st embodiment. FIG. 3 is a side view of the heat exchanger 4 according to the first embodiment in the vicinity of the folded portion 33. FIG. 4 is a longitudinal sectional view of the joint 34 according to the first embodiment. FIG. 3 is a cross-sectional view of the joint 34 according to the first embodiment. Sectional drawing in section S of the heat exchanger tube 30 in the heat exchanger of modification 2A. Sectional drawing in section S of heat exchanger tube 30 in heat exchanger 4 of a 2nd embodiment. The side view of the 1st end 4a in heat exchanger 4 of a 2nd embodiment. The side view of the 2nd end part 4b in heat exchanger 4 of a 2nd embodiment. The top view of the heat exchanger 4 of 1st Embodiment, and the intercooler 7. Sectional drawing in section S of heat exchanger 4 of a 1st embodiment, and intercooler 7. The longitudinal section of the joint 34a and reinforcement part 304a of Example 1 of a 3rd embodiment. The longitudinal section of joint 34b and reinforcement part 304b of Example 2 of a 3rd embodiment. FIG. 14 is an external perspective view of a joint 34c and a reinforcing portion 304c according to a third embodiment of the third embodiment. FIG. 18 is an external perspective view of a joint 34d and a reinforcing portion 304d according to a fourth embodiment of the third embodiment. The external appearance perspective view of the joint 34e and the reinforcement part 304e of Example 5 of 3rd Embodiment.

<First embodiment>
(1) Refrigerant circuit configuration of refrigeration apparatus 1 FIG. 1 shows a refrigerant circuit configuration of refrigeration apparatus 1 of the first embodiment. The refrigeration apparatus 1 of the present embodiment is an apparatus that performs a two-stage compression refrigeration cycle using carbon dioxide that is a refrigerant that operates in a supercritical region. The refrigerating apparatus 1 of the present embodiment can be used for an air conditioner for performing cooling and heating, a water heater and the like, and the like.

The refrigerant circuit of the refrigeration apparatus 1 of the present embodiment mainly includes a compressor 2, a four-way switching valve 3, a heat source side heat exchanger 4, an expansion mechanism 5, a use side heat exchanger 6, and an intercooler 7. Have.

The compressor 2 is a two-stage compressor that compresses the refrigerant in two stages by the two

compression elements

2c and 2d. The compressor 2 sucks the refrigerant from the suction pipe 2a, compresses the sucked refrigerant by the first-stage compression element 2c, and discharges the compressed refrigerant to the intermediate refrigerant pipe 8. The refrigerant discharged to the intermediate refrigerant pipe 8 is further drawn into the second stage compression element 2d, compressed, and discharged to the discharge pipe 2b. The discharge pipe 2b is a refrigerant pipe for sending the refrigerant discharged from the compressor 2 to the four-way switching valve 3. The discharge pipe 2b is provided with an oil separator 41 and a check valve 42. The oil separator 41 separates refrigerant oil mixed with the refrigerant discharged from the compressor 2 from the refrigerant. The separated oil is depressurized by the capillary tube 41c and returned to the suction pipe 2a of the compressor 2 via the oil return pipe 41b.

The refrigerating machine oil of the present embodiment is not particularly limited as long as it is a refrigerating machine oil used for a CO ₂ refrigerant. Examples of the refrigerator oil include PAG (polyalkylene glycols) and POE (polyol esters).

(4) The four-way switching valve 3 can switch the flow of the refrigerant flowing through the path connecting the heat source side heat exchanger 4, the expansion mechanism 5, and the use side heat exchanger 6 between a forward direction and a reverse direction. During cooling, the refrigerant flowing out of the compressor 2 flows from the heat source side heat exchanger 4 to the use side heat exchanger 6. At this time, the heat source side heat exchanger 4 is a radiator, and the use side heat exchanger 6 is an evaporator. Conversely, at the time of heating, the refrigerant flowing out of the compressor 2 flows from the use side heat exchanger 6 to the heat source side heat exchanger 4. At this time, the use side heat exchanger 6 is a radiator, and the heat source side heat exchanger 4 is an evaporator.

中間 An intermediate cooler 7 and a check valve 15 are provided in the middle of the intermediate refrigerant pipe 8. That is, the refrigerant that has been compressed by the first-stage compression element 2c exchanges heat with air in the intercooler 7, and flows into the second-stage compression element 2d again.

中間 Further, the intermediate refrigerant pipe 8 is provided with an intermediate cooler bypass pipe 9 so as to bypass the intermediate cooler 7. That is, the refrigerant flowing through the first-stage compression element 2c and the intercooler bypass pipe 9 flows into the second-stage compression element 2d without passing through the intercooler 7. The flow of the refrigerant to the intercooler 7 or the flow of the refrigerant to the intercooler bypass pipe 9 is switched by the on-off valves 11 and 12. Basically, when the use-side heat exchanger 6 is used as an evaporator, a refrigerant flows through the intermediate cooler 7, and conversely, when the use-side heat exchanger 6 is used as a radiator, the intermediate cooling is used. It controls so that a refrigerant | coolant may flow into the container bypass pipe 9. That is, the use of the intercooler 7 is basically for cooling.

Note that the refrigerating apparatus 1 of the present embodiment uses a two-stage compression compressor, but the same applies when two compressors are used. Further, a compressor having three or more stages or a compression mechanism may be used.

(2) Configuration of the outdoor unit 10 of the refrigeration apparatus 1 (2-1) Overall configuration of the outdoor unit 10 The components of the outdoor unit 10 of the refrigeration apparatus 1 of the present embodiment are indicated by dotted lines in FIG. Shown in the figure.

The outdoor unit 10 houses the fan 40, the compressor 2, the heat source side heat exchanger 4, the intercooler 7, the expansion mechanism 5, the four-way switching valve 3, and the oil separator 41 in the casing 20.

(2-2) Heat source side heat exchanger 4
FIG. 2 is an external perspective view of the outdoor unit 10, and FIG. 3A is a perspective view of a part of the heat source side heat exchanger 4.

熱 The heat source side heat exchanger 4 of the present embodiment is disposed on three inner sides of the casing 20 of the outdoor unit 10, as shown in FIG. When the fan 40 rotates, air around the casing 20 is taken in from three sides and passes through the heat source side heat exchanger 4. The air that has entered the casing 20 passes through the fan 40 and is blown out upward from the upper surface of the casing 20. Therefore, the outdoor unit 10 of the present embodiment is a top blow type. The air exchanges heat with the refrigerant while passing through the heat exchanger 4 to be heated or cooled.

概略 An outline of one side of the heat source side heat exchanger 4 of the present embodiment is shown in a perspective view of FIG. The heat exchanger 4 includes a heat transfer tube 30 through which a refrigerant flows, and metal fins 50 that promote heat exchange between the refrigerant and air. The heat transfer tube 30 of the present embodiment is a multi-hole flat tube. In the multi-hole flat tube, a plurality of holes through which the refrigerant flows are arranged in the width direction.

In the heat exchanger 4 of the present embodiment, as shown in FIG. 2, the refrigerant is introduced into the heat transfer tube 30 from outside the heat exchanger 4 at the first end 4a. The refrigerant flows from the first end 4a to three sides of the heat transfer tube 30 that is bent at 90 degrees at two locations, and reaches the second end 4b. When the refrigerant reaches the second end 4b, the flow direction is reversed by 180 °, flows again on the three side surfaces, and returns to the first end 4a. The refrigerant flows out of the heat exchanger 4 from the heat transfer tube 30 at the first end 4a. Here, the heat transfer tube forming the refrigerant flow path from the first end 4a to the second end 4b is referred to as a first heat transfer tube 30a, and the heat transfer tube through which the refrigerant flows in the opposite direction is referred to as a second heat transfer tube 30b. .

In this embodiment, as shown in FIG. 3, the heat transfer tubes 30 are arranged in two rows with respect to the flow of air. In each row, the first heat transfer tubes 30a and the second heat transfer tubes 30b are alternately arranged vertically.

In this specification, the direction of the flow of the refrigerant in the heat exchanger 4 is basically described in the case where the refrigerant is used as a radiator. When used in an evaporator, the direction of the refrigerant is reversed.

(2-3) Configuration of Folding Section 33 The configuration near the second end 4b of the heat source side heat exchanger 4 of the present embodiment will be described with reference to the drawings. The folded portion 33 is disposed at the second end 4b. FIG. 4 is a longitudinal sectional view of the folded portion 33 of the refrigerant. Here, a portion near the second end 4b of the first heat transfer tube 30a is referred to as a first straight portion 31, and a portion near the second end 4b of the second heat transfer tube 30b is referred to as a second straight portion 32.

The folded portion 33 reverses the direction of the refrigerant flowing through the first straight portion 31 of the heat transfer tube 30 (the multi-hole flat tube 300), and flows the coolant to the second straight portion 32 below the first straight portion 31.

The folded portion 33 is formed by using two

joints

34a and 34b and a U-shaped tube 350. The

joints

34a and 34b connect the heat transfer tube 30 and the U-shaped tube 350.

熱 The heat transfer tube 30 may be a multi-hole flat tube or a circular tube, and is not particularly limited. In the present embodiment, a multi-hole flat tube 300 is used. The multi-hole flat tube has high heat transfer performance between the refrigerant and the heat transfer tube. In the multi-hole flat tube 300 of the present embodiment, a plurality of holes are arranged in a line, the arrangement direction of the holes of the multi-hole flat tube is defined as the width direction, and the width direction and the direction perpendicular to the flow direction of the refrigerant are defined as the thickness direction. Call. If the thickness (length in the thickness direction) of the multi-hole flat tube is T and the width (length in the width direction) is W, W> T.

In the present embodiment, the refrigerant that has flowed through the flow passages that are the plurality of holes of the multi-hole flat tube 300 is collected in one flow passage at the folded portion 33. Therefore, the homogenization of the refrigerant is measured in the folded portion 33, that is, the

joints

34a and 34b and the U-shaped tube.

において In the present embodiment, the thickness T of the heat transfer tube 30 in the vertical direction is 3 mm or less. The vertical distance DP between the center of the first straight portion 31 and the center of the second straight portion 32 is 0 mm to 21 mm.

In the present embodiment, in the heat exchanger 4 using the CO ₂ refrigerant, the first straight portion 31 and the second straight portion 32 sandwiching the folded portion 33 of the heat transfer tube 30 are arranged close to each other. Therefore, temperature unevenness of the passing air can be suppressed. Therefore, the heat exchange efficiency is also improved.

熱 In the heat exchanger 4 of the present embodiment, the vertical distance DP between the center of the first straight portion 31 and the center of the second straight portion 32 is not more than five times the thickness T of the heat transfer tube 30 in the vertical direction.

In the present embodiment, in the heat exchanger 4 using the CO ₂ refrigerant, the first straight portion 31 and the second straight portion 32 sandwiching the folded portion 33 of the heat transfer tube 30 are arranged close to each other. Therefore, temperature unevenness of the passing air can be suppressed.

熱 The heat exchanger 4 of the present embodiment further includes a plurality of fins 50. The fins 50 are fixed to the heat transfer tubes 30 and promote heat exchange between the heat transfer tubes 30 and air. The fin pitch of the plurality of fins 50 is at least 1.3 mm, preferably at least 1.4 mm.

熱 In the heat exchanger 4 of the present embodiment, the heat exchange efficiency can be improved by setting the vertical thickness T of the heat transfer tube 30 to 3 mm or less and setting the fin pitch to 1.3 mm or more.

When the heat exchanger 4 of the present embodiment is used as a radiator, the temperature difference between the refrigerant inlet temperature and the refrigerant outlet temperature of the heat exchanger 4 is 40 ° C. or more.

In the present embodiment, a CO ₂ refrigerant is used as the refrigerant. The CO ₂ refrigerant is a supercritical refrigerant, and the temperature of the refrigerant in the radiator greatly decreases. It will be over 40 ° C. Since the temperature difference between the refrigerants is large, the effect of arranging the first straight portion 31 and the second straight portion 32 so as to be close to each other is also great.

熱 In the heat exchanger 4 of the present embodiment, the second straight portion 32 is located above or below the first straight portion 31.

熱 In the heat exchanger 4 of the present embodiment, since the first straight portion 31 and the second straight portion 32 are located above and below, the distance between them is short, and the temperature unevenness of the passing air can be further suppressed. Further, since the fins 50 are connected above and below the heat transfer tube 30, the surrounding temperature approaches through the fins 50.

以上 In addition, the case where the refrigerant flowing through the first linear portion 31 is folded downward to the second linear portion 32 has been described above. The same applies to the case of turning up.

(2-4) Detailed Description of the Joint 34 FIG. 5A is a longitudinal sectional view of the joint 34, and FIG. 5B is a transverse sectional view of the joint 34. As shown in FIGS. 5A and 5B, the joint 34 of the present embodiment connects the multi-hole flat tube 300 and the circular tube 35. In the present embodiment, the circular tube 35 is a U-shaped tube 350. The refrigerant passing therethrough is a CO ₂ refrigerant.

The joint 34 has a first connection portion 301, a main body portion 302, and a second connection portion 303. The first connection part 301 covers the outside of the end of the multi-hole flat tube 300. The main body part 302 is continuous from the first connection part 301. The second connection portion 303 is continuous from the main body. The second connection portion 303 covers the outside of the end of the circular tube 35.

When viewed in the vertical direction, as shown in FIG. 5A, the vertical inner diameter L ₃₀₁ of the first connection portion 301 is slightly larger than the thickness T of the multi-hole flat tube 300. The inner diameter L ₃₀₂ of the main body 302 in the vertical direction is larger than the inner diameter L _{301 of} the first connection part 301 in the vertical direction. Further, the main body portion 302, follow away from the first connecting portion 301, the longitudinal direction of the inner diameter _{L 302} increases, at a certain portion, becomes constant.

On the other hand, when viewed in the lateral direction, as shown in FIG. 5B, the lateral inner diameter W ₃₀₁ of the first connection portion 301 is slightly larger than the width W of the multi-hole flat tube 300. The lateral inner diameter W ₃₀₂ of the main body ₃₀₂ is smaller than the lateral inner diameter W _{301 of} the first connection portion 301. Further, the main body portion 302, follow away from the first connecting portion 301, the lateral inner diameter _{W 302} decreases, at some portions, it becomes constant. The portion where the horizontal inner diameter W ₃₀₂ is constant has the same length as the portion where the vertical inner diameter L ₃₀₂ is constant.

Since the longitudinal inner diameter L ₃₀₂ of the main body 302 of the joint 34 is larger than the longitudinal inner diameter L _{301 of} the first connecting portion 301, the inner peripheral surface of the first connecting portion 301 is close to the multi-hole flat tube 300. Oil does not easily accumulate in oil.

Further, as shown in FIG. 5A, in the present embodiment, the inner diameter of the circular pipe 35 connected to one of the joints 34 is the thickness of the hole of the multi-hole flat tube 300 connected to the other of the joints 34 in the thickness direction. Larger than the diameter.

Furthermore, the thickness of the pipe of the joint 34 is larger than the thickness of the circular pipe 35.

Further, it is preferable that the joint 34 of the present embodiment further includes a reinforcing portion 304 that extends in the longitudinal direction in the refrigerant flow path. The reinforcing section 304 is configured by a reinforcing member. The reinforcing part 304 is arranged near the first connection part 301. The first reinforcing portion 304 connects the upper and lower sides of the pipe constituting the joint 34, and in FIG. 5A, has a role of reinforcing both when receiving a tensile stress and when receiving a compressive stress from above and below the pipe. Since the pressure of the CO ₂ refrigerant is high and the first connection portion 301 has a flat shape, it is preferable to use a reinforcing portion.

(2-4-1) Method of Manufacturing Joint 34 Two methods of manufacturing the joint 34 of the present embodiment will be described.

The first manufacturing method of the joint 34 is a method using a circular pipe.

The circular pipe is a normal circular pipe having a constant inner diameter. The thickness of the circular pipe of the raw material is greater than the thickness of the circular pipe 35 to be connected. To make the first connection portion 301, one end of the circular tube is crushed flat. Then, the lateral inner diameter W ₃₀₁ is slightly smaller than the width W of the multi-hole flat tube 300 such that the longitudinal inner diameter L ₃₀₁ of the end portion is slightly larger than the thickness T of the multi-hole flat tube 300. Process so that it becomes larger.

Although such a manufacturing method is relatively easy to manufacture, it is difficult to insert the reinforcing portion 304. Therefore, this is a manufacturing method used when the reinforcing portion 304 is not used.

The second manufacturing method of the joint 34 is a method using a bonding method.

継手 In the joint 34 shown in FIG. 5A, an upper part and a lower part from the center are separately prepared. It is not necessary to strictly halve the size, and one may be larger.

(4) The reinforcing portion 304 is previously bonded to the upper portion or the lower portion by brazing or the like. The upper part and the lower part are bonded together by brazing or the like to form the joint 34.

(2-5) Intercooler 7
The arrangement of the intercooler 7 of the present embodiment will be described with reference to a top view of FIG. 8A and a cross-sectional view of FIG. 8B.

As shown in FIG. 8A, the intercooler 7 of the present embodiment is arranged on the windward side of the heat exchanger 4 and inside the casing 20 independently of the heat exchanger 4. Here, the term “independent” means that the fins 50 of the heat exchanger 4 and the fins (not shown) of the intercooler 7 are not connected, and the heat exchanger 4 and the intercooler 7 are separate. Has a refrigerant inlet / outlet.

中間 Also, as shown in FIG. 8B, the intercooler is disposed at a height higher than half of the height at which the heat exchanger 4 is disposed.

ファン In the outdoor unit 10 of the present embodiment, the fan 40 is disposed above the heat exchanger 4 and the intercooler 7, and the wind speed increases as the side of the heat exchanger 4 goes upward.

(4) The intercooler 7 is arranged on the upstream side of the heat exchanger 4, so that a sufficient temperature difference between the air and the refrigerant can be secured, and the heat exchange amount can be increased.

Further, since the intercooler 7 is arranged at the upper part, the air flow is relatively large, and the heat exchange amount can be increased.

(3) Features (3-1)
The joint 34 of the present embodiment is used in the refrigeration apparatus 1 using a CO ₂ refrigerant. And the multi-hole flat tube 300 and the circular tube 35 are connected.

The joint 34 has a first connection portion 301, a main body portion 302, and a second connection portion 303. The first connection portion 301 covers the outside of the end of the multi-hole flat tube. The main body part 302 is continuous from the first connection part 301. The second connecting portion 303 is continuous from the main body and covers the outside of the end of the circular tube. In the joint having such a configuration, there is a problem that oil easily accumulates on an inner peripheral surface around a connection portion of the joint 34 with the multi-hole flat tube 300.

Joint 34 of the present embodiment, the longitudinal direction of the inner diameter _{L 302} of the main body portion 302 is larger than the longitudinal direction of the inner diameter _{L 301} of the first connecting portion. Therefore, oil does not easily stay around the connection portion on the inner peripheral surface of the joint 34.

(3-2)
In the joint 34 of the present embodiment, the main body 302 further has a region where the inner diameter in the vertical direction gradually increases as the distance from the first connection portion 301 increases.

油 Owing to such a configuration, oil does not easily stay around the connection portion on the inner peripheral surface of the joint 34.

(3-3)
In one manufacturing method, the joint 34 of the present embodiment is formed by processing one end of a circular pipe. The thickness of the circular pipe of this raw material is larger than the thickness of the circular pipe 35 to be connected. The original portion of the circular tube of the raw material is a portion of the main body portion 302 and a portion having constant inner diameters L ₃₀₂ and W ₃₀₂ .

継手 Since the joint 34 of the present embodiment can be manufactured by adding a simple process to a circular pipe, the manufacturing cost can be suppressed.

(3-4)
The wall thickness of the pipe of the joint 34 of the present embodiment is larger than the thickness of the circular pipe 35. The reason why the thickness of the pipe of the joint 34 is increased is that the joint 34 requires a higher strength than the circular pipe 35 because the joint 34 has a flat portion.

(3-5)
The joint according to the present embodiment further includes a reinforcing portion 304. The reinforcing portion 304 is disposed in the refrigerant flow path of the joint 34 so as to extend in the vertical direction. The reinforcing part 304 connects the upper part and the lower part of the inner wall of the joint 34. There is a reinforcing role in both cases where tensile stress and compressive stress are received from above and below the joint 34. Since the pressure of the CO ₂ refrigerant is high and the first connection portion 301 has a flat shape, it is preferable to use the reinforcing portion 304.

(3-6)
The joint 34 of the present embodiment may be manufactured by bonding two or more members. By manufacturing by bonding, it is possible to easily manufacture a joint having a complicated structure such as including the reinforcing portion 304.

(4) Modification (4-1) Modification 1A
In the first embodiment, the joint 34 is separate from the multi-hole flat tube 300 and the circular tube 35. In the modification 1A, the joint 34 is integral with the circular pipe 35. Other configurations are the same as in the first embodiment.

継手 The joint 34 of Modification 1A has the same features as (3-1) to (3-3) and (3-5), similarly to the joint 34 of the first embodiment.

応用 Further, as an application of the joint 34 of the modified example 1A, the joint 34a, the U-shaped pipe 350, and the joint 34b may be formed as an integrated body as the folded portion 33 as shown in FIG.

<Second embodiment>
(5) Configuration of Heat Exchanger 4 of Second Embodiment In the heat exchanger 4 of the first embodiment and Modification 1A, the heat transfer tubes 30 are folded up and down. That is, the first straight portion 31 and the second straight portion 32 belong to the same column. In the heat exchanger 4 of the second embodiment, the heat transfer tubes 30 are folded over rows. Other configurations of the refrigeration apparatus 1 of the second embodiment are the same as those of the first embodiment and Modification 1A.

構成 The configuration of the heat exchanger 4 of the second embodiment will be described with reference to the drawings. FIGS. 7A and 7B are side views of the first end 4a and the second end 4b viewed from the direction in which the refrigerant flows, and are cross-sectional views perpendicular to the direction in which the refrigerant flows in the middle between the first end 4a and the second end 4b. FIG. 6B shows a cross-sectional view at S. Similarly to the first embodiment, the first heat transfer tube 30a is a heat transfer tube for flowing the refrigerant from the first end 4a to the second end 4b, and the second heat transfer tube 30b is the opposite. Also in the present embodiment, the flow of the refrigerant will be described assuming that the heat exchanger 4 is used as a radiator. When used as an evaporator, the flow of the refrigerant is reversed. In this embodiment, the heat transfer tube is a multi-hole flat tube. The thickness T of the heat transfer tube 30 in the vertical direction is 3 mm or less.

冷媒 In the heat exchanger 4 of the present embodiment, the refrigerant enters the first refrigerant port 401 shown in FIG. 7A. The refrigerant flowing from the first refrigerant inlet / outlet 401 through the first heat transfer tube 30a exchanges heat with air via three side surfaces of the heat exchanger 4 and reaches the second end 4b.

{Circle around (2)} The refrigerant that has reached the second end 4b is returned by the return portion 33 to another row (here, an adjacent windward side row). At this time, the vertical distance DP between the center of the first heat transfer tube 30a (the first straight portion 31) and the center of the second heat transfer tube 30b (the second straight portion 32) is 21 mm or less. The configuration of the folded portion 33 of the present embodiment is the same as the configuration of the modified example 1A. The first heat transfer tube 30a and the second heat transfer tube 30b are composed of two joints 34 and a U-shaped tube 350 connecting them. Connected by

熱 Moreover, the

heat transfer tubes

30a and 30b of the present embodiment are vertically arranged at a period P. The vertical distance DP between the center of the first heat transfer tube 30a (first straight portion 31) and the center of the second heat transfer tube 30b (second straight portion 32) is set to be greater than 0 and smaller than DP. Have been. That is, 0 <DP <P.

{Circle around (2)} The refrigerant returned at the second end 4b flows through the second heat transfer tube 30b, exchanges heat with air while passing through the three side surfaces, and reaches the first end 4a. The refrigerant that has reached the first end flows out from the second refrigerant port 402 into the refrigerant circuit outside the heat exchanger 4.

As described above, in this embodiment, the case where the first heat transfer tube 30a is placed on the leeward side and the second heat transfer tube 30b is placed on the leeward side has been described. The arrangement may be reversed.

In the present embodiment, the case where the heat transfer tube 30 makes only one reciprocation between the first end 4a and the second end 4b has been described. The present invention is also effective when making two or more round trips.

(6) Features of the heat exchanger of the second embodiment The heat exchanger of the second embodiment is similar to the heat exchanger of the first embodiment (3-1) to (3-3), (3--3). 5) to (3-7).

(6-1)
The first heat transfer tube 30a and the second heat transfer tube 30b before and after the folded portion 33 of the heat exchanger 4 of the second embodiment are another adjacent row. Therefore, when viewed in the same row, the first heat transfer pipe 30a and the second heat transfer pipe 30b having different refrigerant temperatures are not arranged side by side, and the temperature distribution in the row is suppressed.

(6-2)
In the heat exchanger 4 of the present embodiment, the first heat transfer tubes 30a and the second heat transfer tubes 30b before and after the turn-back portion 33 are another adjacent row, and the first heat transfer tubes 30a (the first straight portion 31). And the vertical distance DP between the center of the second heat transfer tube 30b (the second straight portion 32) and the center thereof is set to be larger than 0 and smaller than DP.

配置 Due to this arrangement, the second heat transfer tube 30b is not obstructed by the second heat transfer tube 30b even on the leeward first heat transfer tube 30a, and the heat exchange between the air and the refrigerant is promoted.

(6-3)
Further, the first refrigerant port 401 and the second refrigerant port 402 of the present embodiment are arranged in different rows. Therefore, for example, when a refrigerant collecting pipe is separately provided at the inlet / outlet of the refrigerant, it is easy to simply configure the connection pipe.

(7) Modification of Second Embodiment (7-1) Modification 2A
FIG. 6A is a cross-sectional view of a cross section S perpendicular to the direction in which the refrigerant flows in the middle of the first end 4a and the second end 4b of the heat exchanger 4 of Modification Example 2A. Modified example 2A is that the center of the first heat transfer tube 30a (the first straight portion 31) and the center of the second heat transfer tube 30b (the second straight portion 32) in the folded portion 33 of the refrigerant at the second end 4b. The difference from the second embodiment is that the vertical distance DP is 0. The other points are the same as the second embodiment.

熱 The heat exchanger of Modification 2A has the same features as the heat exchanger 4 of the second embodiment, and (6-1) and (6-3).

<Third embodiment>
(8) Structure of the Joint of the Third Embodiment (8-1) Overall Structure of the Joint of the Third Embodiment The joints 34a to 34e of the third embodiment connect the multi-hole flat tube 300 and the circular tube 35. , CO ₂ refrigerant. Each of the joints 34a to 34e has a first connection portion 301, a main body portion 302 continuous from the first connection portion 301, and reinforcing portions 304a to 304e. The first connection portion 301 covers the outside of the end of the multi-hole flat tube 300. The main body part 302 is continuous from the first connection part 301. The reinforcing portions 304a to 304e reinforce the strength of the joints 34a to 34e.

Since the joints 34a to 34e of the present embodiment are connected to the multi-hole flat tube 300, they have a flat shape, and stress tends to concentrate locally. Further, since the CO ₂ refrigerant is used at a high pressure, a large stress is applied to the joint. Furthermore, in consideration of stacking and using the multi-hole flat tubes 300, the thickness of the tube wall of the main body 302 cannot be unnecessarily increased. Since the joints 34a to 34e of the present embodiment have the reinforcing portions 304a to 304e, the joints 34a to 34e can be deformed or broken even if the inside of the joints 34a to 34e becomes high pressure by using CO ₂ refrigerant. Can be suppressed.

The joint 34e of the present embodiment may further include a flat portion 305 that is continuous from the main body 302 and does not form a passage for the refrigerant.

において In the present embodiment, the thickness T and the width W (W> T) of the multi-hole flat tube 300 are defined as in the first embodiment. Then, the thickness direction and the width direction of the multi-hole flat tube 300 are defined as the longitudinal direction and the lateral direction of the joint 34, respectively.

補強 The reinforcing

portions

304a and 304b of the present embodiment may be arranged in the refrigerant flow path so as to extend in the vertical direction.

(4) By arranging the reinforcing portions 304a to 304b in the refrigerant flow path, the portion protruding outside the main body 302 is reduced, and the length of the joints 34a to 34b in the vertical direction can be suppressed.

補強 The reinforcing portions 304c to 304e of the present embodiment may be arranged outside the coolant flow path and in contact with the outer surface of the main body 302.

こと By arranging the reinforcing portions 304c to 304e outside the refrigerant flow path, the reinforcing portions 304c to 304e do not become a resistance to the flow of the refrigerant. Further, it is relatively easy to manufacture to arrange the reinforcing portions 304c to 304e on the outer surface of the main body 302.

補強 The reinforcing portion 304e of the present embodiment may be arranged outside the coolant flow path in contact with the outer surface of the main body 302 and the surface of the flat portion 305.

By arranging the reinforcing portion 304e not only on the outer surface of the main body 302 but also on the surface of the flat portion 305, the strength against the expansion of the main body 302 due to the internal pressure is more reliably secured.

The joints 34 a to 34 e of the present embodiment may further include a second connection portion 303 which is continuous from the main body 302 and covers the outside of the end of the circular tube 35.

In addition, the first connection portions 301 of the joints 34a to 34e of the present embodiment may be formed by processing one end of the circular pipe 35.

In the joint 34 of the present embodiment, the longitudinal inner diameter (L ₃₀₂ ) of the main body 302 may be larger than the longitudinal inner diameter (L ₃₀₁ ) of the first connection portion 301.

In addition, the main body 302 of the joint 34 of the present embodiment may have a region in which the inner diameter in the vertical direction gradually increases as the distance from the first connection portion 301 increases.

The thickness of the pipes of the joints 34a to 34e may be larger than the thickness of the circular pipe 35.

材料 The material of the joints 34a to 34e is metal. The metal is aluminum, copper, iron, or an alloy containing them. The material of the multi-hole flat tube 300 and the circular tube 35 is metal. The metal is aluminum, copper, iron, or an alloy containing them.

(8-2) Manufacturing Method of Joints 34a to 34e of Third Embodiment Two manufacturing methods of the joints 34a to 34e of the third embodiment will be described.

The first manufacturing method of the joints 34a to 34e is a method using a circular pipe.

Circular pipe is a normal circular pipe with a constant inner diameter. The thickness of the circular pipe of the raw material is greater than the thickness of the circular pipe 35 to be connected. To make the first connection portion 301, one end of the circular tube is crushed flat.

FIGS. 11 and 12 show examples of the

joints

34c and 34d created by the first manufacturing method.

２ The second method of manufacturing the joints 34a to 34e is a method using a bonding method.

継手 A joint is formed by deforming and bonding the two plates.

継手 The joint 34e in FIG. 13 is formed by bonding two

deformed plates

3413 and 3414 to form a joint main body 302, a first connection portion 301, and a second connection portion 303.

(8-3) Detailed Description of Reinforcements 304a to 304e of Joints 34a to 34e of Third Embodiment Details of the reinforcements 304a to 304e of joints 34a to 34e of the third embodiment will be described with reference to FIGS. I do.

材料 The material of the reinforcement is metal. The metal is aluminum, copper, iron, or an alloy containing them. The material of the reinforcing portion may be the same as the material of the main body. In this case, there is an advantage that a battery reaction hardly occurs. The material of the reinforcement may be different from the material of the body. A material having good thermal conductivity may be used as a material of the main body portion, and a material having high mechanical strength may be used as a material of the reinforcing portion. The material having good heat conductivity is, for example, aluminum or copper, and the material having high strength is, for example, stainless steel (an alloy containing iron).

(8-3-1) Reinforcing part 304a of joint 34a of the first embodiment
FIG. 9 is a cross-sectional view of the joint 34a and the reinforcing portion 304a of Example 1 of the third embodiment.

The reinforcing portion 304a according to the first embodiment is a rod, and protrusions are arranged at both ends. The rod penetrates the upper and lower portions of the main body portion 302 of FIG. 9 at two places. As a method of manufacturing such a reinforcing portion 304a, for example, a hole is formed in the main body portion 302 of the joint 34a and the hole is closed. The rod is inserted, protrusions are formed at both ends of the rod, and the holes are formed by sealing the holes of the main body 302 by brazing or the like. For example, a rod having a protrusion at one end of a bolt may be inserted from one end of the main body 302, and a nut-like object may be attached at the other end to form a protrusion at the other end.

The reinforcing portion 304a according to the first embodiment suppresses the protrusion from being deformed so that the main body 302 expands even when the refrigerant inside the main body 302 becomes high pressure and pushes the wall of the main body 302 outward. I do.

補強 The number of bars of the reinforcing portion 304a according to the first embodiment may be one or more.

板 Also, like the reinforcing portion 304 of FIGS. 5A and 5B, the reinforcing portion 304 may be plate-shaped. In this case, it is preferable that the heat exchanger extends along the flow path of the refrigerant.

継手 The joint 34a of the first embodiment may be a deformed circular tube or a structure obtained by bonding two plates.

(8-3-2) Reinforcing portion 304b of joint 34b of the second embodiment
The joint 34b according to the second embodiment may be formed by deforming a circular tube or by bonding two plates.

As shown in FIG. 10, the reinforcing portion 304b of the second embodiment is obtained by deforming the main body portion 302 of the joint 34b and bonding the deformed body portion at the abutted portion. The bonding method is, for example, brazing. Therefore, the reinforcing portion 304b has the bonding portion 3041.

補強 The number of the reinforcing portions 304b in the second embodiment may be one or more.

The bonding portion 3041 of the reinforcing portion 304b according to the second embodiment may be a dot-like portion or may extend linearly. When extending in a straight line, it is preferable to extend along the flow path in which the refrigerant flows.

(8-3-3) Reinforcing part 304c of joint 34c of the third embodiment
The joint 34c according to the third embodiment is obtained by deforming a circular pipe.

The reinforcing portion 304c of the third embodiment is a plate (rib) attached to the outside of the main body 302 of the joint 34c as shown in FIG. The plate is attached so that the thickness direction of the plate is along the surface of the main body 302. The main body 302 and the reinforcement 304c are adhered by brazing.

補強 Since the reinforcing portion 304c of the third embodiment is arranged outside the main body portion 302, it does not become a resistance of the refrigerant flow path.

補強 The number of the reinforcing portions 304c of the third embodiment may be one or more.

(8-3-4) Reinforcing part 304d of joint 34d of Example 4
The joint 34d according to the fourth embodiment is obtained by deforming a circular pipe.

補強 As shown in FIG. 12, the reinforcing portion 304d of the fourth embodiment is a plate (rib) attached to the outside of the main body 302 of the joint 34d. The plate is attached so that the surface of the plate is along the surface of the main body 302. The main body 302 and the reinforcement 304c are adhered by brazing.

補強 Since the reinforcing portion 304d of the fourth embodiment is arranged outside the main body portion 302, it does not become a resistance of the refrigerant flow path.

補強 The reinforcing portion 304d of the fourth embodiment may be singular or plural.

The effect of the reinforcing portion 304d of the fourth embodiment is similar to the case where the thickness of the main body of the pipe of the joint is increased. However, compared to the case where the thickness of the main body of the pipe of the joint is simply increased, it is possible to realize a configuration in which only the wall to which pressure is applied is increased, and the portion where pressure is not applied is reduced.

(8-3-5) Reinforcing part 304e of joint 34e of the fifth embodiment
As shown in FIG. 13, a joint 34e according to the fifth embodiment is obtained by bonding two

plates

3413 and 3414 together.

継手 The joint 34e of the fifth embodiment further has a flat portion 305. There are four flat portions 305 at two places on the plate 3413 and two places on the plate 3414. The size of the flat portion 305 is arbitrary. It does not have to be as large as shown in FIG.

As shown in FIG. 11, the four reinforcing portions 304e of the fifth embodiment are plates (ribs) stuck across the boundary between the main body 302 of the joint 34c and the four flat portions 305. The plate is attached so that the thickness direction of the plate is along the surface of the main body 302. The main body 302 and the reinforcement 304c are adhered by brazing.

補強 Since the reinforcing portion 304e of the fifth embodiment is disposed outside the main body portion 302, it does not become a resistance of the refrigerant flow path.

{Circle around (5)} Since the reinforcing portion 304e of the fifth embodiment is also adhered on the flat portion 305, the strength is higher than when the flat portion 305 is not provided.

(8-3-6) Other Examples The joint 34 and the reinforcing portion 304 of the first embodiment disclosed in FIGS. 5A and 5B are also examples of the joint and the reinforcing portion of the third embodiment.

Although the embodiments of the present disclosure have been described above, it will be understood that various changes in form and details can be made without departing from the spirit and scope of the present disclosure described in the claims. .

DESCRIPTION OF SYMBOLS 1 Refrigeration apparatus 2 Compressor 3 Four-way switching valve 4 Heat source side heat exchanger 5 Expansion mechanism 6 User side heat exchanger 7 Intercooler 10 Outdoor unit 20 Casing 30 Heat transfer tube 30a First heat transfer tube 30b Second heat transfer tube 31 First Straight portion 32 Second straight portion 33 Folded

portions

34, 34a to 34e Joint 35 Circular tube 300 Multi-hole flat tube 301 First connection portion 302 Main body portion 303

Second connection portions

304, 304a to 304e Reinforcement portion 305 Flat portion 350 U-shaped Tube 40 fan 50 fin

WO2014 / 199514

Claims

A joint (34) for connecting a multi-hole flat tube (300) having a thickness T and a width W (W> T) to a circular tube (35) and passing a CO 2 refrigerant,
When the thickness direction and the width direction of the multi-hole flat tube are respectively the longitudinal direction and the lateral direction of the joint,
The joint is
A first connection portion (301) that covers the outside of the end of the multi-hole flat tube;
A body portion (302) continuous from the first connection portion;
With
A longitudinal inner diameter (L 302 ) of the main body is larger than a longitudinal inner diameter (L 301 ) of the first connection portion;
Fittings.
The main body is
As the distance from the first connection portion increases, the inner diameter in the vertical direction has a region that is gradually increased.
The joint according to claim 1.
The joint further comprises:
A second connection portion (303) that is continuous from the main body portion and covers the outside of the end of the circular tube;
The joint according to claim 1.
The first connection portion is formed by processing one end of a circular tube.
The joint according to claim 3.
The thickness of the pipe of the joint is thicker than the thickness of the circular pipe,
The joint according to claim 3.
The joint further comprises:
A reinforcing portion (304) for reinforcing the strength of the joint,
Comprising,
The joint according to any one of claims 1 to 5.
The joint is formed by bonding two or more members,
The joint according to any one of claims 1 to 6.
The main body is a part of the circular tube,
The joint according to claim 1.
The joint (34e) further includes a flat portion (305) that is continuous with the main body portion (302) and does not form a passage for the refrigerant.
The joint according to any one of claims 1 to 8.
The reinforcing portion is arranged to extend in the longitudinal direction in the refrigerant flow path,
The joint according to claim 6.
The reinforcing portion is disposed outside the coolant flow path, in contact with an outer surface of the main body portion,
The joint according to claim 6.
The joint (34e) further includes a flat portion (305) that is continuous with the main body portion (302) and does not form a passage for the refrigerant.
The reinforcing portion (304e) is disposed outside the coolant flow path in contact with an outer surface of the main body portion (302) and a surface of the flat portion.
The joint according to claim 6.
A joint according to any of claims 1 to 12,
A multi-hole flat tube connected to the joint,
With
Heat exchanger (4).
A heat exchanger according to claim 13,
Air conditioner (1).