PIPE ARRANGEMENT, COMPRESSOR, COOLING DEVICE AND METHOD FOR MAKING A PIPE ARRANGEMENT

Description

TECHNICAL FIELD

[0001] The present disclosure relates to a tube assembly. The present disclosure further relates to a compressor including a tube assembly and a refrigeration apparatus including a tube assembly. The present disclosure further relates to a method of manufacturing a tube assembly.BACKGROUND ART

[0002] A refrigerant flow path member disclosed in Patent Literature 1 (JP 2020-109297 A) guides a refrigerant, and is mounted on a compressor. The refrigerant flow path member includes two metal members. At the time of manufacturing the refrigerant flow path member, the two metal members are joined to each other by a method such as in-furnace brazing. Further examples of known pipe assemblies are described by documents JPS5918189U, JPS58127281U and JPS6015066A.SUMMARY OF THE INVENTION <Technical Problem>

[0003] When there is a large gap at the joint portion of the two metal members, there is a possibility that the positions or orientations of the two metal members are deviated with respect to each other during a step of brazing. This deviation can cause a defect in a brazed state and reduce the strength of a refrigerant flow path member. As a result, in the compressor equipped with the refrigerant flow path member and a refrigeration apparatus including the compressor, there is a possibility that an operation failure is caused by the deviation.<Solution to Problem>

[0004] Aim of the present invention is to provide a tube assembly, a compressor, a refrigeration apparatus and a method of manufacturing a tube assembly which improve the state of the art indicated above. This aim is achieved by the tube assembly, the compressor, the refrigeration apparatus and the method of manufacturing a tube assembly according to the corresponding appended claims.

[0005] A tube assembly according to a first aspect includes an inner tube, an outer tube, and a brazing material. The inner tube includes an outer peripheral surface first portion and an outer peripheral surface second portion. The inner tube constitutes an injection path of a compressor. The outer tube includes an inner peripheral surface first portion and an inner peripheral surface second portion. The outer tube constitutes the injection path. The inner tube is partially inserted into the outer tube such that the outer peripheral surface first portion is in contact with the inner peripheral surface first portion. The brazing material is disposed in a brazing gap between the outer peripheral surface second portion and the inner peripheral surface second portion. The brazing material fixes the outer peripheral surface second portion and the inner peripheral surface second portion.

[0006] In this configuration, the outer peripheral surface first portion is in contact with the inner peripheral surface first portion. Accordingly, since the inner tube and the outer tube hold each other, the brazing gap can be maintained, and the overall shape and strength of the tube assembly can be maintained.

[0007] A tube assembly according to a second aspect is the tube assembly according to the first aspect, in which the inner tube has an inner tube linear expansion coefficient. The outer tube has an outer tube linear expansion coefficient larger than the inner tube linear expansion coefficient. The brazing material at least partially fixes the inner peripheral surface first portion and the outer peripheral surface first portion.

[0008] In this configuration, the outer tube has a larger linear expansion coefficient than the inner tube. Therefore, since a part of the brazing material enters a gap between the inner peripheral surface first portion and the outer peripheral surface first portion temporarily generated in the process of brazing at a high temperature, the strength of the tube assembly is further secured.

[0009] A tube assembly according to a third aspect is the tube assembly according to the first or second aspect and further includes a tube assembly outer peripheral surface. A part of the brazing material is located at a connecting portion between the inner tube and the outer tube on the tube assembly outer peripheral surface.

[0010] In this configuration, a part of the brazing material extends from the brazing gap to the connecting portion in an axial direction of the tube assembly. Therefore, since the inner tube and the outer tube are more firmly fixed, the strength of the tube assembly is further secured.

[0011] A tube assembly according to a fourth aspect is the tube assembly according to any one of the first to third aspects, in which an inner diameter of the inner tube is 6.4 mm or more.

[0012] In this configuration, the inner diameter has a predetermined size. Therefore, even in the tube assembly that requires a large brazing gap for brazing, contact portions of the inner tube and the outer tube hold each other, and the strength of the tube assembly is further secured.

[0013] A tube assembly according to a fifth aspect is the tube assembly according to any one of the first to fourth aspects, in which a dimension of the brazing gap in a tube assembly radial direction is 50 µm or more and 450 µm or less.

[0014] In this configuration, a minimum value and a maximum value of a radial dimension of the brazing gap are set. Therefore, both the strength of the tube assembly and reliable brazing can be achieved.

[0015] A tube assembly according to a sixth aspect is the tube assembly according to any one of the first to fifth aspects, in which a dimension of the brazing gap in the tube assembly axial direction is 4 mm or more and 6 mm or less.

[0016] In this configuration, a minimum value and a maximum value of the brazing gap in the axial dimension are set. Therefore, both the strength of the tube assembly and reliable brazing can be achieved.

[0017] A tube assembly according to a seventh aspect is the tube assembly according to any one of the first to sixth aspects, in which before the inner tube is inserted into the outer tube, a radial position of the outer peripheral surface first portion is located outside a radial position of the inner peripheral surface first portion by 0.25 mm or less.

[0018] In this configuration, before the inner tube is inserted into the outer tube, the outer peripheral surface first portion is located radially outside the inner peripheral surface first portion by a predetermined dimension. Therefore, the pressure at a contact portion between the outer peripheral surface first portion and the inner peripheral surface first portion can be secured.

[0019] A tube assembly according to an eighth aspect is the tube assembly according to any one of the first to seventh aspects, in which a length of the outer peripheral surface first portion in the tube assembly axial direction is 2 mm or more and 3 mm or less.

[0020] In this configuration, the outer peripheral surface first portion and the inner peripheral surface first portion are in contact with each other over a predetermined axial dimension. Therefore, an axial dimension at the contact portion between the outer peripheral surface first portion and the inner peripheral surface first portion can be secured.

[0021] A tube assembly according to a ninth aspect is the tube assembly according to any one of the first to eighth aspects, in which the inner tube includes an accommodating portion that is adjacent to the outer peripheral surface second portion and accommodates a surplus of the brazing material.

[0022] In this configuration, the inner tube includes the accommodating portion. Therefore, since the surplus of the melted brazing material can be accommodated in the accommodating portion, the entire shape of the tube assembly can be maintained.

[0023] A tube assembly according to a tenth aspect is the tube assembly according to any one of the first to ninth aspects, in which the accommodating portion has an accommodating portion first wall surface, an accommodating portion second wall surface, and an accommodating portion bottom surface. The accommodating portion first wall surface is adjacent to the outer peripheral surface second portion. The accommodating portion second wall surface is apart from the accommodating portion first wall surface. The accommodating portion bottom surface connects the accommodating portion first wall surface and the accommodating portion second wall surface. The inner tube has a point and a corner. The point is formed by the outer peripheral surface second portion and the accommodating portion first wall surface. The corner is formed by the accommodating portion first wall surface and the accommodating portion bottom surface. The point is provided with a curved surface or a chamfered portion. The curved surface forms a curve in a cross section of the inner tube passing through an axis of the inner tube. The chamfered portion forms a straight line in the cross section.

[0024] In this configuration, the inner tube has the curved surface or the chamfered portion at the point. Therefore, the curved surface or the chamfered portion at the point facilitates movement of the melted brazing material to the brazing gap.

[0025] A tube assembly according to an eleventh aspect is the tube assembly according to the tenth aspect, in which the point is provided with the curved surface. A curvature radius of the curved surface is 0.5 mm or more and 1.0 mm or less.

[0026] In this configuration, the inner tube has the curved surface at the point. Therefore, the curved surface at the point facilitates movement of the melted brazing material to the brazing gap.

[0027] A tube assembly according to a twelfth aspect is the tube assembly according to the tenth aspect, in which the point is provided with the chamfered portion. A length of the straight line formed by the chamfered portion (75C) in the cross section is (0.5 × √2) mm or more and (1.0 × √2) mm or less.

[0028] In this configuration, the inner tube has the chamfered portion at the point. Therefore, the chamfered portion at the point facilitates movement of the melted brazing material to the brazing gap.

[0029] A tube assembly according to a thirteenth aspect is the tube assembly according to any one of the tenth to twelfth aspects, in which the corner is provided with the curved surface. The curved surface forms a curve in a cross section of the inner tube passing through an axis of the inner tube.

[0030] In this configuration, the inner tube has the curved surface at the corner. Therefore, the curved surface at the corner facilitates movement of the melted brazing material to the brazing gap.

[0031] A tube assembly according to a fourteenth aspect is the assembly according to any one of the first to thirteenth aspects, in which the inner tube includes a flange that is adjacent to the accommodating portion and bulges outward in the tube assembly radial direction.

[0032] In this configuration, the inner tube includes the flange. Therefore, since the flange suppresses inclination of the outer tube, the entire shape of the tube assembly can be maintained.

[0033] A compressor according to a fifteenth aspect includes a casing, a compression mechanism, a suction pipe, a discharge pipe, and an injection path. The compression mechanism is accommodated in the casing. The suction pipe guides a low-pressure refrigerant outside the casing to the compression mechanism. The discharge pipe guides a high-pressure refrigerant discharged from the compression mechanism to the outside of the casing. The injection path is constituted by the tube assembly according to any one of the first to fourteenth aspects. The injection path supplies a refrigerant from outside of the casing to the compression mechanism.

[0034] In this configuration, the compressor includes the tube assembly in the injection path. Therefore, since the shape and strength of the components constituting the injection path are secured, malfunction of the compressor can be suppressed.

[0035] A refrigeration apparatus according to a sixteenth aspect includes the compressor according to the fifteenth aspect, a decompressor, a heat exchanger, and an injection pipe. The injection pipe guides the refrigerant decompressed by the decompressor to the injection path. The injection pipe includes a bottleneck. A muffler space is defined by the bottleneck and the inner tube.

[0036] In this configuration, the refrigeration apparatus includes the tube assembly in the injection path. Therefore, since the shape and strength of the components constituting the injection path are secured, malfunction of the refrigeration apparatus can be suppressed.

[0037] A tube assembly can be manufactured by a manufacturing method according to a seventeenth aspect. In the manufacturing method, an inner tube including an outer peripheral surface first portion and an outer peripheral surface second portion and constituting an injection path of a compressor is placed such that the outer peripheral surface first portion is located below the outer peripheral surface second portion. The inner tube is inserted by press-fitting into an outer tube that includes an inner peripheral surface first portion and an inner peripheral surface second portion and constitutes the injection path such that the outer peripheral surface first portion is in contact with the inner peripheral surface first portion and the outer peripheral surface second portion and the inner peripheral surface second portion form a brazing gap. A brazing material is disposed before or after the insertion such that the brazing material is located in the brazing gap. The inner tube, the outer tube, and the brazing material are brazed in a furnace, and the brazing material melted by the brazing fixes the outer peripheral surface second portion and the inner peripheral surface second portion.

[0038] In this method, the inner tube is fixed to the outer tube by press-fitting prior to brazing. Therefore, since the positional relationship between the inner tube and the outer tube is stabilized, the shape and strength of the tube assembly are secured.BRIEF DESCRIPTION OF THE DRAWINGS

[0039] FIG. 1 is a schematic diagram of a refrigeration apparatus 100. FIG. 2 is a schematic diagram of a compressor 11. FIG. 3 is an enlarged sectional view of the compressor 11. FIG. 4 is a schematic diagram for describing a muffler space 59. FIG. 5 is a sectional view of a tube assembly 60. FIG. 6 is a partially enlarged view of FIG. 5. FIG. 7 is a schematic diagram illustrating a manufacturing step of the tube assembly 60. FIG. 8 is another schematic diagram illustrating the manufacturing step of the tube assembly 60. FIG. 9 is a sectional view of the tube assembly 60 according to a modification. DESCRIPTION OF EMBODIMENTS <Basic embodiment>(1) Overall configuration

[0040] FIG. 1 shows a refrigeration apparatus 100. The refrigeration apparatus 100 acquires cold or heat from a heat source and provides the cold or heat to a user. A specific form of the refrigeration apparatus 100 is, for example, an air conditioner, a refrigerator, a freezer, a water heater, a floor heater, or a washing and drying machine.

[0041] The refrigeration apparatus 100 includes a refrigerant circuit RC that circulates a refrigerant. The refrigerant circuit RC includes one heat source unit 10, one utilization unit 20, and a connection pipe 30. Alternatively, one refrigeration apparatus 100 may include a plurality of heat source units 10 and a plurality of utilization units 20.(1-1) Heat source unit 10

[0042] The heat source unit 10 acquires cold or heat from air as a heat source. The heat source unit 10 includes a compressor 11, a four-way switching valve 12, a heat source heat exchanger 13, a heat source fan 14, a heat source expansion valve 15, a liquid shutoff valve 17, and a gas shutoff valve 18. The heat source unit 10 further includes an intermediate-pressure refrigerant generator 40 and an injection pipe 45.

[0043] The compressor 11 suctions and compresses a low-pressure refrigerant R1 and discharges a high-pressure refrigerant R2 in a direction of an arrow in the drawing. The four-way switching valve 12 achieves a connection indicated by the solid lines in FIG. 1 during a cold providing operation, and achieves a connection indicated by the broken lines in FIG. 1 during a heat providing operation. The heat source heat exchanger 13 functions as a condenser or a heat radiator during the cold providing operation, and functions as an evaporator or a heat absorber during the heat providing operation. The heat source fan 14 promotes heat exchange between the air and the refrigerant performed in the heat source heat exchanger 13. The heat source expansion valve 15 functions as a decompressor for decompressing the refrigerant. Furthermore, the heat source expansion valve 15 adjusts a circulation amount of the refrigerant. The liquid shutoff valve 17 and the gas shutoff valve 18 shut off the refrigerant circuit RC when the refrigeration apparatus 100 is installed or the like.

[0044] The intermediate-pressure refrigerant generator 40 includes a subcooling heat exchanger 41 and a subcooling valve 42. The subcooling heat exchanger 41 includes a first flow path x and a second flow path y. During the cold providing operation, a decompressed refrigerant R4 decompressed by the heat source expansion valve 15 passes through the first flow path x. The cooling gas passing through the second flow path y applies a degree of subcooling to the decompressed refrigerant R4 by cooling the decompressed refrigerant R4 passing through the first flow path x. The subcooling valve 42 generates a cooling gas by decompressing the decompressed refrigerant R4 that has passed through the first flow path x. After passing through the second flow path y, the cooling gas passes through the injection pipe 45 as an intermediate-pressure refrigerant R3, and is then guided to an injection path 54 described later included in the compressor 11. The injection pipe 45 includes a bottleneck 46 having a flow path sectional area smaller than other parts.(1-2) Utilization unit 20

[0045] The utilization unit 20 provides cold or heat to the user. The utilization unit 20 includes a utilization heat exchanger 21 and a utilization fan 22. The utilization heat exchanger 21 functions as an evaporator or a heat absorber during the cold providing operation, and functions as a condenser or a heat radiator during the heat providing operation. The utilization fan 22 promotes heat exchange between the air and the refrigerant performed in the utilization heat exchanger 21.(1-3) Connection pipe 30

[0046] The connection pipe 30 constitutes the refrigerant circuit RC through which the refrigerant circulates by connecting the heat source unit 10 and the utilization unit 20. The connection pipe 30 includes a liquid connection pipe 31 and a gas connection pipe 32. The liquid connection pipe 31 is connected to the liquid shutoff valve 17 and guides a liquid refrigerant or a gas-liquid two-phase refrigerant. The gas connection pipe 32 is connected to the gas shutoff valve 18 and guides the low-pressure refrigerant R1 or the high-pressure refrigerant R2 in a gaseous state.(2) Configuration of compressor 11

[0047] FIG. 2 shows the compressor 11. The compressor 11 includes a casing 51, a compression mechanism 55, and a motor 56.

[0048] The casing 51 houses the compression mechanism 55 and the motor 56. The casing 51 is provided with a suction pipe 52, a discharge pipe 53, and the injection path 54. The suction pipe 52 guides the low-pressure refrigerant R1 outside the casing 51 to the compression mechanism 55. The discharge pipe 53 guides the high-pressure refrigerant R2 discharged from the compression mechanism 55 to the outside of the casing 51. The injection pipe 45 of the refrigerant circuit RC is connected to the injection path 54. The injection path 54 is a refrigerant passage configured to directly supply the intermediate-pressure refrigerant R3 having a pressure higher than the pressure of the low-pressure refrigerant R1 and lower than the pressure of the high-pressure refrigerant R2 to a compression chamber 57 of the compression mechanism 55.

[0049] The motor 56 receives electric power from the outside and generates motive power for driving the compression mechanism 55.

[0050] The compression mechanism 55 includes a compression chamber 57. The compression mechanism 55 suctions the low-pressure refrigerant R1 provided via the suction pipe 52 into the compression chamber 57. The compression mechanism 55 feeds the high-pressure refrigerant R2 generated in the compression chamber 57 to the discharge pipe 53.(3) Configuration of tube assembly 60

[0051] As shown in FIG. 3, the injection path 54 is constituted by the tube assembly 60. The tube assembly 60 includes an inner tube 70 and an outer tube 80.

[0052] The inner tube 70 is one of the components constituting the injection path 54. The inner tube 70 is made of iron, for example. The inner tube 70 has an inner diameter H1. The linear expansion coefficient of the inner tube 70 is an inner tube linear expansion coefficient α.

[0053] The outer tube 80 is also one of the components constituting the injection path 54. The outer tube 80 is made of copper, for example. The outer tube 80 has an inner diameter H2. The inner diameter H2 is larger than the inner diameter H1. The linear expansion coefficient of the outer tube 80 is an outer tube linear expansion coefficient β. The outer tube linear expansion coefficient β is larger than the inner tube linear expansion coefficient α.

[0054] As shown in FIG. 4, the injection path 54 constituted by the tube assembly 60 forms a flow path of the intermediate-pressure refrigerant R3 by being connected with the injection pipe 45. The inner tube 70 having the small inner diameter H1 constitutes one bottleneck in the flow path. Furthermore, the flow path includes the bottleneck 46 of the injection pipe 45. A section sandwiched by these two bottlenecks forms a muffler space 59. The muffler space 59 has a function of reducing noise caused by pressure pulsation of the intermediate-pressure refrigerant R3.

[0055] FIG. 5 shows the structure of the tube assembly 60. The inner tube 70 and the outer tube 80 share an axis 70A. The drawing shows the structure of the tube assembly 60, that is, the inner tube 70 and the outer tube 80 in a cross section passing through the axis 70A of the inner tube 70. The tube assembly 60 has a tube assembly outer peripheral surface 62. The tube assembly outer peripheral surface 62 is a portion that can be visually recognized from outside of the tube assembly 60. The tube assembly outer peripheral surface 62 includes an outer peripheral surface of the inner tube 70 and an outer peripheral surface of the outer tube 80.

[0056] The outer peripheral surface of the inner tube 70 includes an outer peripheral surface base portion 79, an outer peripheral surface first portion 71, an outer peripheral surface second portion 72, an accommodating portion 73, and a flange 74 in that order. In a tube assembly radial direction r, the outer peripheral surface base portion 79 is located on the outermost side among them. Next, the outer peripheral surface first portion 71, the outer peripheral surface second portion 72, and the accommodating portion 73 are located inward in that order. The accommodating portion 73 is located in the innermost side. The accommodating portion 73 can accommodate a surplus 66 of a brazing material 61. The accommodating portion 73 is adjacent to the outer peripheral surface second portion 72. The flange 74 bulges outward in the tube assembly radial direction r. The flange 74 is adjacent to the accommodating portion 73.

[0057] An inner peripheral surface of the outer tube 80 includes an inner peripheral surface first portion 81, an inner peripheral surface second portion 82, and an inner peripheral surface residual portion 83 in that order. The inner peripheral surface first portion 81 and the inner peripheral surface second portion 82 have the inner diameter H2. A part of the inner peripheral surface residual portion 83 has the inner diameter H2. An end surface of the outer tube 80 adjacent to the inner peripheral surface first portion 81 is in contact with an end surface of the inner tube 70 adjacent to the outer peripheral surface base portion 79, and both end surfaces constitute a connecting portion 63 between the inner tube 70 and the outer tube 80 on the tube assembly outer peripheral surface 62. The connecting portion 63 can be visually recognized from outside of the tube assembly 60.

[0058] By partially inserting the inner tube 70 into the outer tube 80, the outer peripheral surface first portion 71 comes into contact with the inner peripheral surface first portion 81, and a brazing gap 65 is formed between the outer peripheral surface second portion 72 and the inner peripheral surface second portion 82. The brazing gap 65 is a place where the brazing material 61 is disposed in a manufacturing step of the tube assembly 60. The brazing material 61 fixes the outer peripheral surface second portion 72 and the inner peripheral surface second portion 82 by melting and then fixing. A part of the brazing material 61 penetrates between the outer peripheral surface first portion 71 and the inner peripheral surface first portion 81. Therefore, the brazing material 61 at least partially fixes the outer peripheral surface first portion 71 and the inner peripheral surface first portion 81. As a result of the brazing material 61 penetrating between the outer peripheral surface first portion 71 and the inner peripheral surface first portion 81, a part of the brazing material 61 may be located at the connecting portion 63 of the tube assembly outer peripheral surface 62.

[0059] FIG. 6 shows a periphery of the accommodating portion 73 of the tube assembly 60. However, FIG. 6 does not show the brazing material 61. The accommodating portion 73 has an accommodating portion first wall surface 731, an accommodating portion second wall surface 732, and an accommodating portion bottom surface 733. The accommodating portion first wall surface 731 is adjacent to the outer peripheral surface second portion 72. The accommodating portion second wall surface 732 is apart from the accommodating portion first wall surface 731. The accommodating portion bottom surface 733 connects the accommodating portion first wall surface 731 and the accommodating portion second wall surface 732. The inner tube 70 has a point 75 and a corner 76. The point 75 is formed by the outer peripheral surface second portion 72 and the accommodating portion first wall surface 731. The corner 76 is formed by the accommodating portion first wall surface 731 and the accommodating portion bottom surface 733.

[0060] The point 75 is provided with a curved surface 75R. The curved surface 75R forms a curve in a cross section of the inner tube 70 passing through the axis 70A of the inner tube 70. The corner 76 is provided with a curved surface 76R. The curved surface 76R forms a curve in a cross section of the inner tube 70 passing through the axis 70A of the inner tube 70.(4) Design parameters of tube assembly 60

[0061] An example of design parameters of the tube assembly 60 will be described below with reference to FIG. 5.

[0062] The inner diameter H1 of the inner tube 70 is 6.4 mm or more.

[0063] The inner diameter H2 of the outer tube 80 is 18 mm or more.

[0064] A dimension Gr of the brazing gap 65 in the tube assembly radial direction r is 50 µm or more and 450 µm or less.

[0065] A dimension Ga of the brazing gap 65 in a tube assembly axial direction a is 4 mm or more and 6 mm or less.

[0066] A length Ta of the outer peripheral surface first portion 71 in the tube assembly axial direction a is 2 mm or more and 3 mm or less.

[0067] Another example of the design parameters of the tube assembly 60 will be described with reference to FIG. 6. A curvature radius c of the curved surface 75R is 0.5 mm or more and 1.0 mm or less.(5) Method of manufacturing tube assembly 60

[0068] The tube assembly 60 is manufactured by the following procedure.

[0069] As a first step, as shown in FIG. 7, the inner tube 70 is placed such that the outer peripheral surface first portion 71 is located below the outer peripheral surface second portion 72.

[0070] As a second step, as shown in FIG. 8, the inner tube 70 is disposed above the outer tube 80, and preparation for inserting the inner tube 70 into the outer tube 80 by press-fitting is performed. As shown in FIG. 8, before the inner tube 70 is inserted into the outer tube 80, it is desirable that a radial position P1 of the outer peripheral surface first portion 71 is located outside a radial position P2 of the inner peripheral surface first portion 81 by Δ = 0.25 mm or less. This arrangement enables press fitting.

[0071] As a third step, prior to the insertion, the brazing material 61 is disposed on the outer peripheral surface second portion 72 forming the brazing gap 65. This arrangement is to position the brazing material 61 in the brazing gap 65 after insertion. Alternatively, the brazing material 61 may be disposed in the brazing gap 65 after insertion.

[0072] As a fourth step, the inner tube 70 is inserted into the outer tube 80 by press-fitting. As a result of the press-fitting, the outer peripheral surface first portion 71 comes into contact with the inner peripheral surface first portion 81, and the outer peripheral surface second portion 72 and the inner peripheral surface second portion 82 form the brazing gap 65.

[0073] As a fifth step, an aggregate of the inner tube 70, the outer tube 80, and the brazing material 61 is brazed in a furnace. As a result, as shown in FIG. 5, the melted brazing material 61 fixes the outer peripheral surface second portion 72 and the inner peripheral surface second portion 82. A part of the brazing material 61 preferably penetrates between the outer peripheral surface first portion 71 and the inner peripheral surface first portion 81. More preferably, a part of the brazing material 61 is exposed from the connecting portion 63 to the tube assembly outer peripheral surface 62.(6) Characteristics

[0074] (6-1) In the tube assembly 60, the outer peripheral surface first portion 71 is in contact with the inner peripheral surface first portion 81. Therefore, since the inner tube 70 and the outer tube 80 hold each other, a normal shape of the brazing gap 65 can be maintained both during the manufacturing step of the tube assembly 60 and after the manufacturing of the tube assembly 60 is completed. Therefore, an overall shape and strength of the tube assembly 60 can be maintained. (6-2) The outer tube linear expansion coefficient β, which is the linear expansion coefficient of the outer tube 80, is larger than the inner tube linear expansion coefficient α, which is the linear expansion coefficient of the inner tube 70. Therefore, since a part of the brazing material 61 enters a gap between the inner peripheral surface first portion 81 and the outer peripheral surface first portion 71 temporarily generated in the process of brazing at a high temperature, the strength of the tube assembly 60 is further secured. (6-3) A part of the brazing material 61 extends from the brazing gap 65 to the connecting portion 63 in the tube assembly axial direction a. Therefore, since the inner tube 70 and the outer tube 80 are more firmly fixed, the strength of the tube assembly 60 is further secured. (6-4) Before the inner tube 70 is inserted into the outer tube 80, the outer peripheral surface first portion 71 is located radially outside the inner peripheral surface first portion 81 by a predetermined dimension. Therefore, the pressure at a contact portion between the outer peripheral surface first portion 71 and the inner peripheral surface first portion 81 can be secured. (6-5) The inner tube 70 has the accommodating portion 73. Therefore, since the surplus 66 of the melted brazing material 61 can be accommodated in the accommodating portion 73, the entire shape of the tube assembly 60 can be maintained. (6-6) The point 75 is provided with a curved surface 75R. The curvature radius c of the curved surface 75R can be 0.5 mm or more and 1.0 mm or less. Such a curved surface 75R facilitates movement of the melted brazing material 61 to the brazing gap 65. The curved surface 76R provided at the corner 76 also promotes the movement of the melted brazing material 61 in some cases. (6-7) The inner tube 70 has the flange 74. Therefore, since the flange 74 suppresses inclination of the outer tube 80, the entire shape of the tube assembly 60 can be maintained. (6-8) The compressor 11 and the refrigeration apparatus 100 including the compressor 11 include the tube assembly 60 in the injection path 54. Therefore, since the shape and strength of the components constituting the injection path 54 are secured, malfunction of the compressor 11 and the refrigeration apparatus 100 can be suppressed. (6-9) In the manufacturing step of the tube assembly 60, the inner tube 70 is fixed to the outer tube 80 by press-fitting before brazing. Therefore, since the positional relationship between the inner tube 70 and the outer tube 80 is stabilized, the shape and strength of the tube assembly 60 are secured. <Modification of basic embodiment>(7) Modifications

[0075] FIG. 9 is a structure of the tube assembly 60 according to a modification.

[0076] While the curved surface 75R is provided at the point 75 in the embodiment described above, a chamfered portion 75C is provided at the point 75 in the modification. The chamfered portion 75C forms a straight line L in the cross section of the inner tube 70 passing through the axis 70A of the inner tube 70.

[0077] A length of the straight line L formed by the chamfered portion 75C in the cross section is (0.5 × √2) mm or more and (1.0 × √2) mm or less.

[0078] Such a chamfered portion 75C also facilitates movement of the melted brazing material 61 to the brazing gap 65.<Conclusion>

[0079] The embodiments of the present disclosure have been described above. It will be understood that various changes to modes and details are possible.REFERENCE SIGNS LIST

[0080] 10: heat source unit 11: compressor 12: four-way switching valve 13: heat source heat exchanger 14: heat source fan 15: heat source expansion valve 17: liquid shutoff valve 18: gas shutoff valve 20: utilization unit 21: utilization heat exchanger 22: utilization fan 30: connection pipe 31: liquid connection pipe 32: gas connection pipe 40: intermediate-pressure refrigerant generator 41: subcooling heat exchanger 42: subcooling valve 45: injection pipe 46: bottleneck 51: casing 52: suction pipe 53: discharge pipe 54: injection path 55: compression mechanism 56: motor 57: compression chamber 59: muffler space 60: tube assembly 61: brazing material 62: tube assembly outer peripheral surface 63: connecting portion 65: brazing gap 66: surplus 70: inner tube 70A: axis 71: outer peripheral surface first portion 72: outer peripheral surface second portion 73: accommodating portion 74: flange 75: point 75C: chamfered portion 75R: curved surface 76: corner 76R: curved surface 79: outer peripheral surface base portion 80: outer tube 81: inner peripheral surface first portion 82: inner peripheral surface second portion 83: inner peripheral surface residual portion 100: refrigeration apparatus 731: accommodating portion first wall surface 732: accommodating portion second wall surface 733: accommodating portion bottom surface Ga: dimension Gr: dimension H1: inner diameter H2: inner diameter L: length of straight line P1: radial position P2: radial position R1: low-pressure refrigerant R2: high-pressure refrigerant R3: intermediate-pressure refrigerant R4: decompressed refrigerant RC: refrigerant circuit a: tube assembly axial direction c: curvature radius r: tube assembly radial direction x: first flow path y: second flow path α: inner tube linear expansion coefficient β: outer tube linear expansion coefficient CITATION LIST PATENT LITERATURE

[0081] Patent Literature 1: JP 2020-109297 A

Claims

1. A tube assembly (60) comprising: an inner tube (70) that has an outer peripheral surface base portion (79), an outer peripheral surface first portion (71),an outer peripheral surface second portion (72), an accommodating portion (73), and a flange (74) in that order; an outer tube (80) that has an inner peripheral surface first portion (81) and an inner peripheral surface second portion (82) andan inner peripheral surface residual portion (83) in that order , the outer tube (80) having the inner tube partially inserted into the outer tube such that the outer peripheral surface first portion is in contact with the inner peripheral surface first portion; and a brazing material (61) that is disposed in a brazing gap (65) between the outer peripheral surface second portion and the inner peripheral surface second portion and is configured to fix the outer peripheral surface second portion and the inner peripheral surface second portion, wherein an end surface of the outer tube (80) adjacent to the inner peripheral surface first portion (81) is in contact with an end surface of the inner tube (70) adjacent to the outer peripheral surface base portion (79), and both end surfaces constitute a connecting portion 63 between the inner tube (70) and the outer tube (80) on an outer peripheral surface (62) of the tube assembly.

2. The tube assembly according to claim 1, wherein the inner tube has an inner tube linear expansion coefficient (α), the outer tube has an outer tube linear expansion coefficient (β) larger than the inner tube linear expansion coefficient, and the brazing material is configured to at least partially fix the inner peripheral surface first portion and the outer peripheral surface first portion.

3. The tube assembly according to claim 1 or 2, further comprising a tube assembly outer peripheral surface (62), wherein a part of the brazing material is located at a connecting portion (63) between the inner tube and the outer tube on the tube assembly outer peripheral surface.

4. The tube assembly according to any one of claims 1 to 3, wherein an inner diameter (H1) of the inner tube is 6.4 mm or more.

5. The tube assembly according to any one of claims 1 to 4, wherein a dimension (Gr) of the brazing gap (65) in a tube assembly radial direction (r) is 50 µm or more and 450 µm or less.

6. The tube assembly according to any one of claims 1 to 5, wherein a dimension (Ga) of the brazing gap (65) in a tube assembly axial direction (a) is 4 mm or more and 6 mm or less.

7. The tube assembly according to any one of claims 1 to 6, wherein before the inner tube is inserted into the outer tube, a radial position (P1) of the outer peripheral surface first portion (71) is located outside a radial position (P2) of the inner peripheral surface first portion (81) by 0.25 mm or less.

8. The tube assembly according to any one of claims 1 to 7, wherein a length (Ta) of the outer peripheral surface first portion (71) in the tube assembly axial direction (a) is 2 mm or more and 3 mm or less.

9. The tube assembly according to any one of claims 1 to 8, wherein the inner tube includes the accommodating portion (73) is adjacent to the outer peripheral surface second portion (72) and is configured to accommodate a surplus (66) of the brazing material.

10. The tube assembly according to any one of claims 1 to 9, wherein the accommodating portion (73) includes an accommodating portion first wall surface (731) adjacent to the outer peripheral surface second portion (72), an accommodating portion second wall surface (732) apart from the accommodating portion first wall surface, and an accommodating portion bottom surface (733) that connects the accommodating portion first wall surface (731) and the accommodating portion second wall surface (732), the inner tube (70) includes a point (75) constituted by the outer peripheral surface second portion (72) and the accommodating portion first wall surface (731), and a corner (76) constituted by the accommodating portion first wall surface (731) and the accommodating portion bottom surface (733), and the point (75) is provided with a curved surface (75R) that forms a curve in a cross section of the inner tube (70) passing through an axis (70A) of the inner tube (70), or a chamfered portion (75C) that forms a straight line in the cross section.

11. The tube assembly according to claim 10, wherein the point (75) is provided with the curved surface (75R), and a curvature radius (c) of the curved surface (75R) is 0.5 mm or more and 1.0 mm or less.

12. The tube assembly according to claim 10, wherein the point (75) is provided with the chamfered portion (75C), and a length (L) of the straight line formed by the chamfered portion (75C) in the cross section is (0.5 × √2) mm or more and (1.0 × √2) mm or less.

13. The tube assembly according to any one of claims 10 to 12, wherein the corner (76) is provided with a curved surface (76R) that forms a curve in the cross section of the inner tube (70) passing through the axis (70A) of the inner tube (70).

14. The tube assembly according to any one of claims 1 to 13, wherein the flange (74) is adjacent to the accommodating portion (73) and bulges outward in the tube assembly radial direction (r).

15. A compressor (11) comprising: a casing (51); a compression mechanism (55) accommodated in the casing; a suction pipe (52) configured to guide a low-pressure refrigerant (R1) outside the casing to the compression mechanism; a discharge pipe (53) configured to guide a high-pressure refrigerant (R2) discharged from the compression mechanism to outside of the casing; and an injection path (54) that is constituted by the tube assembly (60) according to any one of claims 1 to 14 and is configured to supply a refrigerant to the compression mechanism from outside of the casing.

16. A refrigeration apparatus (100) comprising: the compressor (11) according to claim 15; a decompressor (15); a heat exchanger (13, 21); and an injection pipe (45) configured to guide a refrigerant (R4) decompressed by the decompressor to the injection path, wherein the injection pipe includes a bottleneck (46), and a muffler space (59) is defined by the bottleneck and the inner tube.

17. A method of manufacturing a tube assembly (60) comprising: placing an inner tube (70) that includes an outer peripheral surface base portion (79), an outer peripheral surface first portion (71),an outer peripheral surface second portion (72) an accommodating portion (73), and a flange (74) in that order such that the outer peripheral surface first portion is located below the outer peripheral surface second portion (72); inserting the inner tube (70) by press-fitting into an outer tube (80) that includes an inner peripheral surface first portion (81), an inner peripheral surface second portion (82), an inner peripheral surface residual portion (83) in that ordersuch that the outer peripheral surface first portion (71) is in contact with the inner peripheral surface first portion (81) and the outer peripheral surface second portion (72) and the inner peripheral surface second portion (82) form a brazing gap (65); arranging a brazing material (61) before the inserting or after the inserting such that the brazing material is located in the brazing gap; and brazing the inner tube, the outer tube, and the brazing material in a furnace such that the brazing material melted by the brazing fixes the outer peripheral surface second portion and the inner peripheral surface second portion. wherein an end surface of the outer tube (80) adjacent to the inner peripheral surface first portion (81) is in contact with an end surface of the inner tube (70) adjacent to the outer peripheral surface base portion (79), and both end surfaces constitute a connecting portion (63) between the inner tube (70) and the outer tube (80) on an outer peripheral surface (62) of the tube assembly.