Compressor and refrigeration cycle device

Abstract

The present invention provides a compressor and a refrigeration cycle device that can be made compact. [Solution] A compressor according to a first aspect of the embodiment has a compression mechanism, an electric motor, and a case. The compression mechanism compresses gas. The electric motor drives the compression mechanism. The case houses the compression mechanism and the electric motor. The case has a cylindrical portion, a flat portion, and an intermediate portion. The flat portion is located at the axial end of the cylindrical portion and is perpendicular to the axial direction. The intermediate portion is located between the cylindrical portion and the flat portion. In a cross section including the central axis of the cylindrical portion, the intermediate portion has a shape formed by continuously connecting multiple arc portions that are convex from the inside to the outside of the case.

Description

[Technical Field]

[0001] An embodiment of the present invention relates to a compressor and a refrigeration cycle device. [Background technology]

[0002] A refrigeration cycle device uses a compressor that compresses a refrigerant. The compressor has a compression mechanism, an electric motor, and a case. The compression mechanism compresses the refrigerant. The electric motor drives the compression mechanism. The case houses the compression mechanism and the electric motor. Compressors are required to be compact. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] International Publication No. 2017 / 164138 Summary of the Invention [Problem to be solved by the invention]

[0004] An object of the present invention is to provide a compressor and a refrigeration cycle device that can be made compact. [Means for solving the problem]

[0005] The compressor of aspect 1 of the embodiment has a compression mechanism, an electric motor, and a case. The compression mechanism compresses gas. The electric motor drives the compression mechanism. The case houses the compression mechanism and the electric motor. The case has a cylindrical main case and a bowl-shaped end case. The end case covers an opening at an axial end of the main case and is joined to the main case. The end case has a cylindrical portion, a flat portion, and an intermediate portion. The cylindrical portion is joined to the main case. The flat portion is located at the axial end and perpendicular to the axial direction. The intermediate portion is located between the cylindrical portion and the flat portion. In a cross section including the central axis of the cylindrical portion, the intermediate portion has a shape formed by continuously connecting multiple arc portions that are convex from the inside to the outside of the case.

[0006] A compressor according to a second aspect of the embodiment is based on the compressor according to the first aspect. The plurality of arc portions include a first arc portion, a second arc portion, and a third arc portion. The first arc portion is continuous with the cylindrical portion. The second arc portion is continuous with the first arc portion. The third arc portion is continuous with the second arc portion and the flat portion.

[0007] A compressor according to a third aspect of the embodiment is based on the compressor according to the second aspect. The first radius of curvature of the first arc-shaped portion and the third radius of curvature of the third arc-shaped portion are smaller than the second radius of curvature of the second arc-shaped portion.

[0008] A compressor according to a fourth aspect of the embodiment is based on the compressor according to any one of the first to third aspects. The compression mechanism compresses gas to 7 MPa or more.

[0009] The refrigeration cycle device of the embodiment includes a compressor according to any one of claims 1 to 4, a heat radiator connected to the compressor, an expansion device connected to the heat radiator, and a heat sink connected between the expansion device and the compressor. [Brief explanation of the drawings]

[0010] [Figure 1] 1 is a circuit diagram of a refrigeration cycle device and a cross-sectional view of a compressor. [Figure 2] FIG. 3 is a cross-sectional view of an upper case in the embodiment. [Figure 3] FIG. 10 is a cross-sectional view of an upper case in a comparative example. [Figure 4] Graph showing stress distribution in the upper case. DETAILED DESCRIPTION OF THE INVENTION

[0011] Hereinafter, a compressor and a refrigeration cycle device according to an embodiment will be described with reference to the drawings. 1 is a circuit diagram of a refrigeration cycle apparatus 1 and a cross-sectional view of a compressor 90. The refrigeration cycle apparatus 1 includes a compressor 90, a four-way valve 3, a first heat exchanger 4, an expansion device 5, a second heat exchanger 6, and a refrigerant flow path 8 that circulates a refrigerant through these elements. The refrigerant circulates through the refrigeration cycle apparatus 1 while undergoing a phase change.

[0012] The compressor 90 compresses the low-pressure gas refrigerant taken in to produce high-temperature, high-pressure gas refrigerant. An accumulator (gas-liquid separator) 2b is arranged upstream of the compressor 90. The accumulator 2b separates the gas-liquid two-phase refrigerant and supplies the gas refrigerant to the compressor 90.

[0013] The four-way valve 3 reverses the flow direction of the refrigerant in the refrigerant flow path 8 of the first heat exchanger 4, the expansion device 5, and the second heat exchanger 6. When the four-way valve 3 is in the state shown in Figure 1, the refrigerant discharged from the compressor 90 flows through the first heat exchanger 4, the expansion device 5, and the second heat exchanger 6 in that order. At this time, the first heat exchanger 4 functions as a condenser (heat radiator), and the second heat exchanger 6 functions as an evaporator (heat absorber). When the four-way valve 3 is switched from the state shown in Fig. 1, the refrigerant discharged from the compressor 90 flows sequentially through the second heat exchanger 6, the expansion device 5, and the first heat exchanger 4. At this time, the second heat exchanger 6 functions as a condenser (heat radiator), and the first heat exchanger 4 functions as an evaporator (heat absorber).

[0014] The condenser dissipates heat from the high-temperature, high-pressure gas refrigerant discharged from the compressor 90, and converts the high-temperature, high-pressure gas refrigerant into a high-pressure liquid refrigerant. The expansion device 5 reduces the pressure of the high-pressure liquid refrigerant sent from the condenser, and converts the high-pressure liquid refrigerant into a low-temperature, low-pressure two-phase gas-liquid refrigerant. For example, the expansion device 5 is an expansion valve. The evaporator converts the gas-liquid two-phase refrigerant sent from the expansion device 5 into low-pressure gas refrigerant. When the low-pressure gas-liquid two-phase refrigerant evaporates in the evaporator, it absorbs heat of vaporization from the surroundings, thereby cooling the surroundings. The low-pressure gas refrigerant that has passed through the evaporator is taken into the compressor 90 described above via the accumulator 2b.

[0015] In this way, the refrigerant, which is a working fluid, circulates while changing phases between gas and liquid in the refrigeration cycle apparatus 1. The refrigerant releases heat during the phase change from gas to liquid, and absorbs heat during the phase change from liquid to gas. The refrigeration cycle apparatus 1 performs heating, cooling, defrosting, etc. by utilizing the heat release or absorption of the refrigerant.

[0016] The compressor 90 has a compression mechanism 92, an electric motor 93, and a case 30. The compression mechanism 92 compresses the refrigerant. For example, when the refrigerant is carbon dioxide (CO2), the compression mechanism 92 compresses the gaseous refrigerant to 7 MPa or more (up to approximately 14 MPa). The electric motor 93 drives the compression mechanism 92.

[0017] Case 30 houses compression mechanism 92 and electric motor 93. Inside case 30, high-pressure gas refrigerant compressed by compression mechanism 92 is housed. Case 30 has main case 10, upper case (end case) 20, and lower case (end case) 38. Main case 10 is formed into a cylindrical shape from a steel pipe material or the like.

[0018] In this application, the Z direction and R direction of the cylindrical coordinate system are defined as follows: The Z direction is the axial direction of the main case 10. The +Z side is the upper case 20 side of the main case 10. The -Z side is the opposite side to the +Z side. For example, the Z direction is the vertical direction, the +Z side is the upper side, and the -Z side is the lower side. The R direction is the radial direction of the main case 10. The +R side (first side) is the outer side of the R direction, and the -R side (second side) is the inner side of the R direction. For example, the R direction is the horizontal direction.

[0019] The upper case 20 is formed into a bowl shape by drawing a steel plate material or the like. The -Z side end of the upper case 20 is inserted into the -R side of the +Z side end of the main case 10. The upper case 20 covers the opening at the +Z side end of the main case 10. The upper case 20 is joined to the main case 10 by welding.

[0020] The lower case 38 is formed in the same manner as the upper case 20. The lower case 38 covers the opening at the end of the main case 10 on the -Z side and is joined to the main case 10. The lower case 38 may be formed integrally with the main case 10 as part of the main case 10. A bracket 39 for fixing the compressor 90 is connected to the lower case 38.

[0021] 2 is a cross-sectional view of the upper case 20 in this embodiment. The upper case 20 has a generally axially symmetrical shape with the central axis of the main case 10 as the axis of symmetry. The upper case 20 has a cylindrical portion 26, a flat portion 28, and an intermediate portion 27.

[0022] The cylindrical portion 26 is disposed at the end on the -Z side, that is, the end on the +R side. The -Z side end of the cylindrical portion 26 fits into the +Z side end of the main case 10. The cylindrical portion 26 is joined to the main case 10.

[0023] The flat portion 28 is located at the end on the +Z side and in the center in the R direction. The flat portion 28 is formed in a flat plate shape perpendicular to the Z direction. The flat portion 28 has a substantially circular shape when viewed from the Z direction. Terminals of the electric motor 93 are installed on the flat portion 28 (see FIG. 1).

[0024] The intermediate portion 27 is disposed between the cylindrical portion 26 and the flat portion 28 in the Z direction and the R direction. The intermediate portion 27 has a shape in which a plurality of arc portions 21, 22, and 23 are continuously connected in a cross section including the central axis of the cylindrical portion 26. The plurality of arc portions 21, 22, and 23 are convex from the inside to the outside of the case 30.

[0025] The plurality of arcuate portions 21, 22, 23 include a first arcuate portion 21, a second arcuate portion 22, and a third arcuate portion 23. First arcuate portion 21 is disposed at the −Z side and +R side ends of intermediate portion 27. The −Z side end of first arcuate portion 21 smoothly connects to the +Z side end of cylindrical portion 26. The third arcuate portion 23 is disposed at the +Z side and -R side ends of the intermediate portion 27. The -R side end of the third arcuate portion 23 smoothly continues to the +R side end of the flat portion 28.

[0026] The second arc portion 22 is disposed in the center of the intermediate portion 27 in the Z and R directions. The -Z and +R end portions of the second arc portion 22 smoothly connect to the +Z and -R end portions of the first arc portion 21. The +Z and -R end portions of the second arc portion 22 smoothly connect to the -Z and +R end portions of the third arc portion 23.

[0027] The second radius of curvature R2 of the second arc portion 22 is different from the first radius of curvature R1 of the first arc portion 21 and the third radius of curvature R3 of the third arc portion 23. The first radius of curvature R1 and the third radius of curvature R3 are smaller than the second radius of curvature R2. The first radius of curvature R1 and the third radius of curvature R3 may be the same as or different from each other.

[0028] 3 is a cross-sectional view of an upper case 20p in a comparative embodiment. The cylindrical portion 26 and flat portion 28 of the upper case 20p in the comparative embodiment (sometimes referred to as the comparative case) are the same as those of the upper case 20 in the embodiment (sometimes referred to as the working case). The middle portion 27p of the comparative case 20p has only one arc portion 24 in a cross section including the central axis of the cylindrical portion 26. The -Z side end of the arc portion 24 smoothly continues to the +Z side end of the cylindrical portion 26. The -R side end of the arc portion 24 smoothly continues to the +R side end of the flat portion 28.

[0029] As described above, a high-pressure gaseous refrigerant is accommodated inside the case 30. The high-pressure gaseous refrigerant causes the center of the flat portion 28 to bend outward. As a result, a large tensile stress acts on the outer surface of the center of the flat portion 28. If the stress acting on the flat portion 28 is kept below the allowable stress, the case 30 can withstand the high pressure of the refrigerant.

[0030] The inventors of the present application performed structural analysis using the finite element method on the comparative case 20p and the experimental case 20. The numbers and positions of the nodes set in the structural analysis are shown on the left side of Figures 2 and 3. In the structural analysis, a boundary condition corresponding to a refrigerant pressure of 14 MPa was set on the inner surface of the upper case.

[0031] FIG. 4 is a graph showing the stress distribution in the upper cases 20 and 20p. The horizontal axis of FIG. 4 represents the node number. The vertical axis of FIG. 4 represents the stress ratio normalized based on the stress at the 16th node N16. As shown in FIGS. 2 and 3, the 16th node N16 is a node set on the outer surface at the center of the flat portion 28.

[0032] The larger the diameter of the flat portion 28 in the R direction, the easier it is for the flat portion 28 to bend outward, and the greater the stress acting on the 16th node N16. The flat portion 28 has the same shape in the comparative case 20p and the practical case 20. In the structural analysis, the stress acting on the 16th node N16 in both the comparative case 20p and the practical case 20 was 274.5 MPa. 274.5 MPa is smaller than the allowable stress of the steel material constituting the case 30.

[0033] In both Comparative Case 20p and Experimental Case 20, the node on which the maximum stress acts is the 16th node N16. That is, the stress acting on nodes other than the 16th node N16 is lower than the stress at the 16th node N16. It has been confirmed by an actual machine that Comparative Case 20p can withstand high refrigerant pressure. The results of the structural analysis confirmed that Experimental Case 20 can also withstand high refrigerant pressure.

[0034] On the other hand, there is a demand for a compact compressor 90. The intermediate portion 27 of the embodiment case 20 has a plurality of arcuate portions 21, 22, and 23. The radii of curvature R1, R2, and R3 of the arcuate portions 21, 22, and 23 can be set appropriately. As a result, the height H in the Z direction of the embodiment case 20 shown in FIG. 2 can be made smaller than the height Hp in the Z direction of the comparison case 20p shown in FIG. 3.

[0035] In particular, the first radius of curvature R1 of the first arc portion 21 of the example case 20 is smaller than the radius of curvature Rp of the arc portion 24 of the comparative case 20p. As a result, the height H of the example case 20 is smaller than the height Hp of the comparative case 20p. As a result, the compressor 90 can be made smaller in size.

[0036] As described above in detail, the compressor 90 of this embodiment has a compression mechanism 92, an electric motor 93, and a case 30. The compression mechanism 92 compresses a gas refrigerant. The electric motor 93 drives the compression mechanism 92. The case 30 houses the compression mechanism 92 and the electric motor 93. The case 30 has a cylindrical main case 10 and a bowl-shaped upper case 20. The upper case 20 covers the opening at the end of the main case 10 in the Z direction and is joined to the main case 10. The upper case 20 has a cylindrical portion 26, a flat portion 28, and an intermediate portion 27. The cylindrical portion 26 is joined to the main case 10. The flat portion 28 is located at the end of the Z direction and is perpendicular to the Z direction. The intermediate portion 27 is located between the cylindrical portion 26 and the flat portion 28. In a cross section including the central axis of the cylindrical portion 26, the intermediate portion 27 has a shape in which a plurality of arc portions 21, 22, 23 that are convex from the inside to the outside of the case 30 are continuously connected.

[0037] The radii of curvature R1, R2, and R3 of the arcuate portions 21, 22, and 23 can be set appropriately. This reduces the height of the upper case 20 in the Z direction, thereby enabling the compressor 90 to be made more compact. Furthermore, the diameter of the flat portion 28 is limited, thereby suppressing stress acting on the center of the flat portion 28.

[0038] The multiple arc portions 21, 22, 23 include a first arc portion 21, a second arc portion 22, and a third arc portion 23. The first arc portion 21 is continuous with the cylindrical portion 26. The second arc portion 22 is continuous with the first arc portion 21. The third arc portion 23 is continuous with the second arc portion 22 and the flat portion 28. The shape of the upper case 20 changes gradually due to the three arcuate portions 21, 22, and 23. This prevents stress concentration on the upper case 20.

[0039] The first radius of curvature R1 of the first arc-shaped portion 21 and the third radius of curvature R3 of the third arc-shaped portion 23 are smaller than the second radius of curvature R2 of the second arc-shaped portion 22.

[0040] Because the first radius of curvature R1 is smaller than the second radius of curvature R2, the height in the Z direction of the upper case 20 can be reduced. Because the third radius of curvature R3 is smaller than the second radius of curvature R2, the center of the flat portion 28 is less likely to bend even when high pressure is applied inside the case 30. This makes it possible to suppress the stress acting on the center of the flat portion 28.

[0041] The compression mechanism 92 compresses the gas refrigerant to 7 MPa or more. Even in this case, the case 30 can hold high-pressure gas refrigerant inside.

[0042] The refrigeration cycle device 1 of the embodiment has the above-mentioned compressor 90, radiators 4, 6 connected to the compressor 90, an expansion device 5 connected to the radiators 4, 6, and heat sinks 6, 4 connected between the expansion device 5 and the compressor 90. The compressor 90 described above can be made smaller, which allows the refrigeration cycle device 1 to be made smaller.

[0043] The shape of the upper case 20 detailed in the embodiment may also be applied to the lower case 38. When the lower case 38 is formed integrally with the main case 10 as a part of the main case 10, the shape may also be applied to the lower case 38 formed integrally with the main case 10.

[0044] In the embodiment, the upper case 20 is inserted on the −R side of the main case 10. Alternatively, the main case 10 may be inserted on the −R side of the upper case 20. In this embodiment, the intermediate portion 27 has three arc portions 21, 22, and 23. Alternatively, the intermediate portion 27 may have two arc portions or four or more arc portions.

[0045] According to at least one of the embodiments described above, the case 30 has a plurality of arcuate portions 21, 22, 23 that are convex from the inside to the outside. This allows the compressor 90 to be made smaller.

[0046] Although several embodiments of the present invention have been described, these embodiments are presented as examples and are not intended to limit the scope of the invention. These embodiments can be implemented in various other forms, and various omissions, substitutions, and modifications can be made without departing from the spirit of the invention. These embodiments and their modifications are included within the scope and spirit of the invention, as well as within the scope of the invention described in the claims and their equivalents. [Explanation of symbols]

[0047] R1...first radius of curvature, R2...second radius of curvature, R3...third radius of curvature, 1...refrigeration cycle device, 4...first heat exchanger (heat radiator, heat absorber), 5...expansion device, 6...second heat exchanger (heat absorber, radiator), 10...main case, 20...upper case (end case), 21...first arc portion, 22...second arc portion, 23...third arc portion, 26...cylindrical portion, 27...middle portion, 28...flat portion, 30...case, 38...lower case (end case), 90...compressor, 92...compression mechanism portion, 93...electric motor.

Claims

1. a compression mechanism that compresses gas; an electric motor that drives the compression mechanism; a case that houses the compression mechanism and the electric motor, The case has a cylindrical main case and a bowl-shaped end case, the end case is joined to the main case, covering an opening at an end of the main case in the axial direction; the end case has a cylindrical portion joined to the main case, a flat portion disposed at an end in the axial direction and perpendicular to the axial direction, and an intermediate portion disposed between the cylindrical portion and the flat portion, the intermediate portion has a shape in which a plurality of arc portions that are convex from the inside to the outside of the case are continuously connected in a cross section including the central axis of the cylindrical portion. Compressor.

2. The plurality of arcuate portions include a first arcuate portion continuous with the cylindrical portion, a second arcuate portion continuous with the first arcuate portion, and a third arcuate portion continuous with the second arcuate portion and the flat portion. The compressor according to claim 1 .

3. a first radius of curvature of the first arc portion and a third radius of curvature of the third arc portion are smaller than a second radius of curvature of the second arc portion; The compressor according to claim 2 .

4. The compression mechanism compresses the gas to 7 MPa or more. The compressor according to any one of claims 1 to 3.

5. A compressor according to any one of claims 1 to 3; a radiator connected to the compressor; an expansion device connected to the heat sink; a heat sink connected between the expansion device and the compressor. Refrigeration cycle equipment.

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