Rotor of thrust magnetic bearing, thrust magnetic bearing and rotary fluid machinery

Abstract

The rotor of the thrust magnetic bearing is a rotor (51) of a thrust magnetic bearing (50), wherein the thrust magnetic bearing (50) supports a rotating shaft (30) in an axial direction, and the rotating shaft (30) is driven to rotate by a motor (20). A rotor passage (93) is provided on the rotor (51), and the rotor passage (93) passes through the rotor (51) and is a part of a refrigerant passage (Z) for conveying refrigerant to the motor (20). The rotor passage (93) includes an opening portion (93b) provided on one direction side of the axial direction and an opening portion (93a) provided on the other direction side of the axial direction, and preferably, the opening portion (93b) on the one direction side is located at a position radially more outward (Q2) than the opening portion (93a) on the other direction side.

Description

Technical Field

[0001] The present disclosure relates to a rotor of a thrust magnetic bearing, a thrust magnetic bearing and a rotary fluid machine. Background Art

[0002] A centrifugal compressor is disclosed in Patent Document 1. The centrifugal compressor described in Patent Document 1 forms a refrigerant passage on a rotating shaft so as to pass through the axis of the rotating shaft, rotates the rotating shaft to generate centrifugal force, thereby supplying refrigerant into a casing through the refrigerant passage, and uses the refrigerant to cool a motor disposed in the casing.

[0003] Prior art literature

[0004] Patent Literature

[0005] Patent Document 1: Japanese Patent Publication No. 2020-167924 Summary of the invention

[0006] -Technical problem to be solved by the invention-

[0007] In the case where the refrigerant passage is formed to be eccentric with respect to the axis of the rotating shaft, when the rotating shaft rotates, the refrigerant tends to flow to a position away from the axis of the rotating shaft, so the supply of the refrigerant is not balanced. Therefore, when forming the refrigerant passage on the rotating shaft, high concentricity is required between the rotating shaft and the refrigerant passage. However, generally, since the depth of the refrigerant passage is longer than the diameter of the refrigerant passage, the ratio of the depth of the refrigerant passage to the diameter of the refrigerant passage is large. As a result, when the refrigerant passage is formed, the front end of the refrigerant passage is prone to vibrate. Therefore, in order to ensure the concentricity between the rotating shaft and the refrigerant passage, the rotating shaft needs to be processed with high precision, and the processing process is relatively complicated.

[0008] An object of the present disclosure is to simplify the structure of a refrigerant passage.

[0009] -Technical solutions to solve technical problems-

[0010] The first aspect is directed to a rotor of a thrust magnetic bearing. The rotor of the thrust magnetic bearing is a rotor 51 of a thrust magnetic bearing 50, the thrust magnetic bearing 50 axially supports a rotating shaft 30, and the rotating shaft 30 is driven to rotate by a motor 20. The rotor 51 is engaged with the rotating shaft 30, and the rotor 51 is a component separate from the rotating shaft 30. The rotor 51 is provided with a rotor passage 93, which passes through the rotor 51 and is a part of a refrigerant passage Z for conveying refrigerant to the motor 20.

[0011] In the first aspect, the configuration of the refrigerant passage Z can be simplified.

[0012] In the second aspect, based on the first aspect, the rotor passage 93 includes an opening portion 93b arranged on one direction side of the axial direction and an opening portion 93a arranged on the other direction side of the axial direction, and the opening portion 93b on the one direction side is located at a position radially outer side Q2 than the opening portion 93a on the other direction side.

[0013] In the second aspect, the refrigerant can be efficiently sent from the first rotor opening portion 93 a to the second rotor opening portion 93 b in the rotor passage 93 by utilizing the centrifugal force generated by the rotation of the rotating shaft 30 .

[0014] A third aspect is the first or second aspect, wherein the rotor passage 93 includes a first rotor passage portion 93A and a second rotor passage portion 93B extending in directions perpendicular to each other.

[0015] In the third aspect, the refrigerant can be efficiently pressure-fed using the pump function of the rotor passage (93).

[0016] The fourth aspect is directed to a thrust magnetic bearing, which includes the rotor 51 described in any one of the first to third aspects, and a stator 52 disposed opposite to the rotor 51 .

[0017] In the fourth aspect, the structure of the refrigerant passage Z can be simplified.

[0018] A fifth aspect is based on the fourth aspect, wherein the refrigerant passage Z includes a stator passage (94) provided on the stator (52).

[0019] In the fifth aspect, the stator (52) can be cooled by the refrigerant flowing through the stator passage (94).

[0020] A sixth aspect is the aspect according to the fifth aspect, wherein the refrigerant passage Z includes a rotor groove (93c) formed in an annular shape along the outer circumference of the rotor (51).

[0021] In the sixth aspect, the refrigerant can be caused to flow through the refrigerant passage Z in a stable manner.

[0022] The seventh aspect is directed to a rotary fluid machine, which includes the thrust magnetic bearing 50 according to any one of the fourth to sixth aspects, the motor 20 , and the rotating shaft 30 .

[0023] In the seventh aspect, the structure of the refrigerant passage Z can be simplified.

[0024] According to the eighth aspect, based on the seventh aspect, the rotary fluid machine includes a bearing (81a) that rotatably supports the rotary shaft (30), and the bearing (81a) is arranged on the refrigerant passage (Z).

[0025] In the eighth aspect, the bearing (81a) can be cooled by the refrigerant flowing in the refrigerant passage (Z).

[0026] According to a ninth aspect, based on the seventh or eighth aspect, the rotary fluid machine includes a grounding member 83 for grounding the rotating shaft 30 , and the grounding member 83 is opposite to the axial center portion 30 a of the rotating shaft 30 .

[0027] In the ninth aspect, it is possible to suppress the grounding member 83 from sliding on the rotating shaft 30 and being worn as the rotating shaft 30 rotates.

[0028] In the tenth aspect, based on any one of the seventh to ninth aspects, the motor 20 is located on one direction side of the axial direction relative to the thrust magnetic bearing 50, a first space S1 exists on the other direction side of the axial direction relative to the thrust magnetic bearing 50, and a second space S2 exists on one direction side of the axial direction relative to the thrust magnetic bearing 50, and by transporting refrigerant to the second space S2 through the rotor passage 93, the pressure of the second space S2 becomes higher than the pressure of the first space S1.

[0029] In the tenth aspect, the first thrust magnetic bearing 50 can be miniaturized and / or the power consumption of the first thrust magnetic bearing 50 can be reduced.

[0030] The eleventh aspect is based on the tenth aspect and includes a housing 10 that accommodates the thrust magnetic bearing 50, and the thrust magnetic bearing 50 divides the space in the housing 10 into the first space S1 and the second space S2.

[0031] In the eleventh aspect, the space in the housing (10) can be partitioned into the first space (S1) and the second space (S2) by the thrust magnetic bearing (50). BRIEF DESCRIPTION OF THE DRAWINGS

[0032] Figure 1 is a schematic diagram of the overall structure of the refrigeration device involved in the implementation mode;

[0033] Figure 2 is a cross-sectional view of the compressor;

[0034] Figure 3 is a schematic diagram of a compressor;

[0035] Figure 4 yes Figure 2 An enlarged partial view of the compressor shown;

[0036] Figure 5 is a diagram showing a refrigerant passage;

[0037] Figure 6 is a diagram showing a second embodiment of a compressor;

[0038] Figure 7 is a diagram showing a third embodiment of the compressor;

[0039] Figure 8 is a diagram showing a fourth embodiment of the compressor;

[0040] Fig. 9 It is a perspective view showing the outer peripheral structure of the rotor of the first thrust magnetic bearing. DETAILED DESCRIPTION

[0041] The following is a detailed description of the embodiments of the present disclosure with reference to the accompanying drawings. It should be noted that the present disclosure is not limited to the embodiments shown below, and various changes can be made without departing from the technical concept of the present disclosure. The drawings are used to briefly illustrate the present disclosure, so in order to facilitate understanding, the size, ratio or quantity is sometimes exaggerated or simplified as needed.

[0042] Exemplary embodiments are described in detail below with reference to the accompanying drawings.

[0043] <Overall structure>

[0044] Reference Figures 1 to 3 , the compressor 100 is described. The compressor 100 is an example of a rotary fluid machine of the present invention. The compressor 100 is, for example, a centrifugal compressor. The compressor 100 sucks in a refrigerant, compresses the sucked refrigerant, and then ejects it. The refrigerant is, for example, HFC refrigerant R32. It should be noted that R32 is only an example of a type of refrigerant, and the compressor 100 can also compress a refrigerant other than R32 and eject it.

[0045] like Figure 1 As shown, the compressor 100 is installed in a refrigeration device 200. The refrigeration device 200 includes a refrigerant circuit 210 filled with refrigerant. The refrigerant circuit 210 has a compressor 100, a condenser 201, an expansion valve 202, an evaporator 203, a refrigerant passage 206 provided between the compressor 100 and the evaporator 203, and a refrigerant passage 207 provided between the compressor 100 and the condenser 201.

[0046] The first branch path 204 and the second branch path 205 are connected to the refrigerant circuit 210. One end of the first branch path 204 is connected to the evaporator 203. The other end of the first branch path 204 is connected to the refrigerant passage Z of the compressor 100 (see Figure 5 ) is connected to the inflow end of the refrigerant passage Z. One end of the second branch passage 205 is connected to the outflow end of the refrigerant passage Z. The other end of the second branch passage 205 is connected to the evaporator 203.

[0047] The compressor 100 is driven by an impeller 40 (see Figure 2 and Figure 3 ) rotates to compress the refrigerant flowing into the impeller chamber that accommodates the impeller 40. The refrigerant compressed by the compressor 100 is supplied to the condenser 201 via the refrigerant passage 207, and condenses by releasing heat to the air in the condenser 201. The refrigerant condensed in the condenser 201 is decompressed by the expansion valve 202. The refrigerant decompressed by the expansion valve 202 absorbs heat from the air in the evaporator 203 and evaporates. The refrigerant evaporated in the evaporator 203 is sent to the compressor 100 through the refrigerant passage 206, and is compressed again in the compressor 100.

[0048] A portion of the refrigerant sent to the evaporator 203 is supplied to the compressor 100 via the first branch path 204. The refrigerant supplied to the compressor 100 passes through the compressor 100, is supplied to the second branch path 205, and is supplied to the evaporator 203 via the second branch path 205.

[0049] like Figure 2 and Figure 3 As shown, the compressor 100 includes a casing 10, a motor 20, a rotating shaft 30, an impeller 40, a first thrust magnetic bearing 50, a second thrust magnetic bearing 60, a first radial magnetic bearing 71, a second radial magnetic bearing 72, a first bottoming bearing 81 and a second bottoming bearing 82.

[0050] The housing 10 is a hollow member. The housing 10 includes a first housing portion 11, a second housing portion 12, a third housing portion 13, and a fourth housing portion 14. The first housing portion 11 to the fourth housing portion 14 are arranged in the order of the first housing portion 11, the second housing portion 12, the third housing portion 13, and the fourth housing portion 14 toward one direction of the axial direction. The axial direction is a direction parallel to the extension direction of the rotation shaft 30.

[0051] The first housing portion 11 is provided as an end portion on one axial direction side of the closed housing 10. The second housing portion 12 is connected to the first housing portion 11. A first thrust magnetic bearing 50 and a first bottoming bearing 81 are provided in the second housing portion 12. The third housing portion 13 is connected to the second housing portion 12. A motor 20, a second thrust magnetic bearing 60, a first radial magnetic bearing 71, and a second radial magnetic bearing 72 are provided in the third housing portion 13. The fourth housing portion 14 is connected to the third housing portion 13. The impeller 40 and the second bottoming bearing 82 are provided in the fourth housing portion 14.

[0052] The rotating shaft 30 is driven to rotate by the motor 20. As the rotating shaft 30 is driven to rotate, the impeller 40 (see Figure 2 and Figure 3) rotates, and the refrigerant flowing into the impeller chamber is compressed. The stator 21 of the motor 20 is fixed to the inner circumferential wall of the casing 10. The rotor 22 is arranged radially inside the stator 21. The radial direction is a direction passing through the axis P of the rotating shaft 30 and perpendicular to the axial direction. The radial inner side Q1 is a direction toward the axis P side of the rotating shaft 30 in the radial direction. The radial outer side Q2 is a direction away from the axis P of the rotating shaft 30 in the radial direction. The rotor 51 is embedded in the rotating shaft 30. The rotor 51 is a component separate from the rotating shaft 30.

[0053] The rotating shaft 30 is fixed to the radial inner side Q1 of the rotor 22. The rotating shaft 30 extends in the axial direction. The impeller 40 is fixed to one side of the rotating shaft 30 in the axial direction.

[0054] The first radial magnetic bearing 71 is located on the other axial side of the motor 20. The second radial magnetic bearing 72 is located on one axial side of the motor 20. The first radial magnetic bearing 71 and the second radial magnetic bearing 72 rotatably support the rotating shaft 30 on the housing 10 by magnetic suspension.

[0055] The first thrust magnetic bearing 50 and the second thrust magnetic bearing 60 support the rotating shaft 30 in the axial direction. Supporting the rotating shaft 30 in the axial direction means supporting the rotating shaft 30 in a manner that the axial position of the rotating shaft 30 is within a prescribed range. The first thrust magnetic bearing 50 is located on the other axial direction side relative to the first radial magnetic bearing 71. The first thrust magnetic bearing 50 uses magnetic force to pull the rotating shaft 30 to the other axial direction side. The second thrust magnetic bearing 60 is located on one axial direction side relative to the second radial magnetic bearing 72. The second thrust magnetic bearing 60 uses magnetic force to pull the rotating shaft 30 to one axial direction side.

[0056] The impeller 40 rotates, and the pressure acts on the rotating shaft 30 in one axial direction. The rotating shaft 30 is pulled in the other axial direction by the first thrust magnetic bearing 50, and the force balance acting on the impeller 40 in the axial direction is adjusted. When the pulling force of the first thrust magnetic bearing 50 (the force pulling the rotating shaft 30 in the other axial direction) is too strong, the rotating shaft 30 is pulled in one axial direction by the second thrust magnetic bearing 60.

[0057] The first bottoming bearing 81 is located on the other side of the axial direction relative to the first thrust magnetic bearing 50. The second bottoming bearing 82 is located on one side of the axial direction relative to the second thrust magnetic bearing 60. The first bottoming bearing 81 and the second bottoming bearing 82 have the function of bearings when the compressor 100 cannot be controlled due to some kind of failure (for example, when the power supply to the first radial magnetic bearing 71 is stopped due to a power outage, etc., so that the rotating shaft 30 cannot be magnetically suspended). In this way, the first thrust magnetic bearing 50, the second thrust magnetic bearing 60, the first radial magnetic bearing 71 and the second radial magnetic bearing 72 can be protected.

[0058] A grounding member 83 is provided on the rotating shaft 30. The grounding member 83 is a member for grounding the rotating shaft 30. The grounding member 83 allows electricity carried by the rotor 22 and the like to pass through, thereby protecting sensors and the like provided on the compressor 100. The grounding member 83 includes, for example, a carbon rod. The grounding member 83 is provided on one axial direction side relative to the rotating shaft 30. The grounding member 83 is opposite to the axial center portion 30a. The axial center portion 30a is a portion of the end portion on the other axial direction side of the rotating shaft 30 that is close to the axis P. The grounding member 83 is pushed toward the rotating shaft 30 side by an elastic member such as a spring.

[0059] <First embodiment>

[0060] like Figures 2 to 4 As shown, the first bottom contact bearing 81 includes a bearing 81a. The bearing 81a rotatably supports the rotating shaft 30. The first thrust magnetic bearing 5 is provided on one side in the axial direction with respect to the bearing 81a.

[0061] The first thrust magnetic bearing 50 includes a rotor 51 , a stator 52 disposed opposite to the rotor 51 , and a coil 53 wound around the stator 52 .

[0062] The rotor 51 is fixed to the rotating shaft 30 and rotates together with the rotating shaft 30 .

[0063] The stator 52 is arranged on the radial outer side Q2 of the rotor 51. The stator 52 includes a first stator portion 52a and a second stator portion 53b. The first stator portion 52a and the second stator portion 53b are fixed to each other. The first stator portion 52a is arranged on the other axial direction side relative to the second stator portion 53b. The first stator portion 52a is opposite to the rotor 51 from the other axial direction side. The second stator portion 53b is opposite to the rotor 51 from the radial outer side Q2. In the present embodiment, the stator 52 is composed of a plurality of components (a first stator portion 52a and a second stator portion 53b), but the present invention is not limited thereto. The number of components constituting the stator 52 is not particularly limited, for example, the stator 52 may also be composed of one component.

[0064] <Space inside the cabinet>

[0065] A first space S1 and a second space S2 are defined in the housing 10 .

[0066] The first space S1 is a space located in one direction of the axial direction relative to the first thrust magnetic bearing 50. The bearing 81a of the first bottoming bearing 81 is provided in the first space S1. The second space S2 is a space located in the other direction of the axial direction relative to the first thrust magnetic bearing 50. The first radial magnetic bearing 71, the motor 20, etc. are provided in the second space S2.

[0067] The housing 10 is provided with a first connecting hole 91 and a second connecting hole 92. The first connecting hole 91 connects the first space S1 with the outside of the housing 10. The first connecting hole 91 is provided in the first housing portion 11. The first branch path 204 (see Figure 1 ) is connected to the first connecting hole 91. The second connecting hole 92 connects the second space S2 and the outside of the housing 10. The second connecting hole 92 is provided on the third housing portion 13. The second connecting hole 92 is connected to the second branch path 205 (refer to Figure 1 ) connected.

[0068] The rotor passage 93 is provided on the rotor 51. The rotor passage 93 is a hole that penetrates the rotor 51. The rotor passage 93 includes a first rotor opening portion 93a and a second rotor opening portion 93b. The first rotor opening portion 93a and the second rotor opening portion 93b respectively connect the inside and the outside of the rotor passage 93. The second rotor opening portion 93b is located at a position closer to the radially outer side Q2 than the first rotor opening portion 93a. The second rotor opening portion 93b is located at a position closer to one direction side in the axial direction than the first rotor opening portion 93a. In the first embodiment, the rotor passage 93 has a shape extending in a straight line from the first rotor opening portion 93a toward the second rotor opening portion 93b. The rotor passage 93 is connected to the first space S1 via the first rotor opening portion 93a, and is connected to the second space S2 via the second rotor opening portion 93b.

[0069] <Structure for dividing the space inside the casing>

[0070] The interior of the housing 10 is divided into a first space S1 and a second space S2 by the first thrust magnetic bearing 50 .

[0071] The separation of the casing 10 into the first space S1 and the second space S2 not only includes a situation where the connection between the first space S1 and the second space S2 is completely blocked so that the fluid cannot flow between the first space S1 and the second space S2, but also includes a situation where the first space S1 and the second space S2 are slightly connected to each other to a degree that ensures that the pressure difference is generated when the air pressure of the first space S1 and the air pressure of the second space S2 are adjusted in order to generate a pressure difference between the first space S1 and the second space S2.

[0072] Hereinafter, a structure for partitioning the interior of the housing 10 into the first space S1 and the second space S2 by the first thrust magnetic bearing 50 will be described.

[0073] The first space S1 and the second space S2 are separated by using a close contact structure in which the stator 52 of the first thrust magnetic bearing 50 is in close contact with the inner wall 10 a of the housing 10 and the characteristics of the first thrust magnetic bearing 50 .

[0074] <Close-fitting structure>

[0075] The stator 52 of the first thrust magnetic bearing 50 is tightly attached to the inner wall 10a of the housing 10, for example, by shrink fit. The tight attachment of the stator 52 to the inner wall 10a of the housing 10 includes not only a state where there is no gap at all between the stator 52 and the inner wall 10a of the housing 10, but also a state where there is a small gap between the stator 52 and the inner wall 10a of the housing 10, and the extent of the small gap is such that the housing 10 is divided into the first space S1 and the second space S2 (the extent that a pressure difference is generated between the first space S1 and the second space S2).

[0076] <Characteristics of the first thrust magnetic bearing>

[0077] The first thrust magnetic bearing 50 has a structure for supporting the rotor 51, which is a rotating body, in a non-contact manner by electromagnetic force. The magnitude of the force for supporting the rotor 51 is determined by the size of the gap between the rotor 51 and the stator 52. Therefore, in order to stably support the rotor 51, the gap must be formed with high precision. In the first thrust magnetic bearing 50, the gap between the rotating part, namely the rotor 51, and the fixed part, namely the stator 52, is set to be narrower than other parts. For example, in the first thrust magnetic bearing 50, the gap between the rotor 51 and the stator 52 is set to about 0.5 mm to 1 mm. In contrast, in the motor 20, the gap between the stator 21 and the rotor 22 is set to about 3 mm, for example. The inventor of the present application has noticed the following characteristics of the first thrust magnetic bearing 50: in the first thrust magnetic bearing 50, by forming the gap between the rotor 51 and the stator 52 to be small and forming the gap with high precision, the rotor 51 and the stator 52 can be effectively sealed, so that the fluid can be effectively suppressed from flowing in the gap between the rotating part, namely the rotor 51, and the fixed part, namely the stator 52. In order to utilize this characteristic, the first thrust magnetic bearing 50 is used as a member for partitioning the first space S1 and the second space S2 .

[0078] By utilizing the close-fitting structure, the flow of the fluid between the stator 52 and the inner wall 10a of the housing 10 can be suppressed, and by the characteristics of the first thrust magnetic bearing 50, the flow of the fluid between the rotating component, i.e., the rotor 51, and the fixed component, i.e., the stator 52 can be suppressed. As a result, by adopting the close-fitting structure and the characteristics of the first thrust magnetic bearing 50, the first space S1 and the second space S2 can be separated, so that a state of pressure difference between the first space S1 and the second space S2 can be effectively ensured. In the first embodiment, the pressure (gas pressure) of the first space S1 is lower than the pressure of the refrigerant just processed by the evaporator 203, and the pressure of the second space S2 is substantially the same as the pressure of the refrigerant just processed by the evaporator 203.

[0079] <Refrigerant passage>

[0080] like Figure 5As shown, a refrigerant passage Z is provided in the housing 10. The refrigerant passage Z is a passage for conveying refrigerant to the motor 20. The refrigerant flowing in the refrigerant passage Z may be gas, or may contain liquid such as mist. The refrigerant passage Z includes a first passage Z1, an intermediate passage Z2, and a second passage Z3.

[0081] The first passage Z1 is a passage for the refrigerant provided in the first space S1. Figure 1 ) is connected to the intermediate passage Z2. The first passage Z1 leads from the first communicating hole 91 to the first space S1, and is connected to the intermediate passage Z2 through the bearing 81a in the first space S1.

[0082] The intermediate passage Z2 is a passage for the refrigerant provided in the first thrust magnetic bearing 50, and is located between the first space S1 and the second space S2. The intermediate passage Z2 is connected to the first passage Z1 and the second passage Z3. In the first embodiment, the intermediate passage Z2 is composed of the rotor passage 93. In the first embodiment, the first rotor opening 93a of the rotor passage 93 is connected to the first passage Z1, and the second rotor opening 93b of the rotor passage 93 is connected to the second passage Z3.

[0083] The second passage Z3 is a passage for the refrigerant provided in the second space S2. The second passage Z3 is connected to the intermediate passage Z2 and the second branch passage 205 (see Figure 1 The second passage Z3 is connected from the intermediate passage Z2 through the first radial magnetic bearing 71 and the motor 20 to the second connecting hole 92.

[0084] <Motor Cooling Operation>

[0085] like Figure 5 As shown, the rotating shaft 30 is driven to rotate by the motor 20, and the rotor 51 of the first thrust magnetic bearing 50 rotates together with the rotating shaft 30. As described above, in the rotor passage 93, the second rotor opening portion 93b is located at a position closer to the radial outside Q2 than the first rotor opening portion 93a. Therefore, when the rotor 51 rotates, the centrifugal force acts on the refrigerant in the rotor passage 93, and the refrigerant is transported from the first rotor opening portion 93a side to the second rotor opening portion 93b side. In this way, the rotor passage 93 that rotates together with the rotating shaft 30 has the function of a pump for transporting the refrigerant. As a result, by utilizing the pump function of the rotor passage 93, the refrigerant can be effectively transported to the first branch passage 204 (refer to Figure 1 ) flowing in the refrigerant.

[0086] When the refrigerant flows in the second passage Z3 and between the stator 21 and the rotor 22 of the motor 20 , the rotor 22 of the motor 20 is cooled by the refrigerant. The refrigerant flowing through the second passage Z3 is sent to the second branch passage 205 via the second communication hole 92 .

[0087] As described above, the structure in which the rotor passage 93 is provided in the rotor 51 and the refrigerant is conveyed by utilizing the pump function of the rotor passage 93 is a first example of the pump structure of the present invention.

[0088] <Effect>

[0089] As described above, the rotor 51 of the first thrust magnetic bearing 50 is provided with a rotor passage 93, which is a part of the refrigerant passage Z that penetrates the rotor 51 and is used to convey the refrigerant to the motor 20. In this way, by rotating the rotating shaft 30 by the motor 20, the rotor 51 rotates together with the rotating shaft 30, and the centrifugal force acts on the refrigerant in the rotor passage 93, and the refrigerant can be effectively flowed in the refrigerant passage Z by utilizing the centrifugal force. In this way, even if a high-precision refrigerant passage Z passing through the axis P of the rotating shaft 30 is not formed, the refrigerant can be effectively flowed in the refrigerant passage Z. As a result, the refrigerant can be made to flow in the refrigerant passage Z by utilizing the centrifugal force generated by the rotation of the rotating shaft 30 with a simple structure.

[0090] Since it is not necessary to form the refrigerant passage Z passing through the axis P of the rotating shaft 30 , and it is not necessary to process the rotating shaft 30 with high precision, it is possible to suppress an increase in the manufacturing cost of the compressor 100 .

[0091] Since it is not necessary to form the refrigerant passage Z passing through the axis P of the rotating shaft 30, the grounding member 83 can be arranged to face the axis portion 30a of the rotating shaft 30. As a result, it is possible to suppress the grounding member 83 from sliding on the rotating shaft 30 and wearing as the rotating shaft 30 rotates.

[0092] In the rotor passage 93, the second rotor opening 93b is located radially outward Q2 from the first rotor opening 93a. Thus, the refrigerant can be efficiently transported from the first rotor opening 93a to the second rotor opening 93b in the rotor passage 93 by utilizing the centrifugal force generated by the rotation of the rotating shaft 30.

[0093] By dividing the space in the housing 10 into the first space S1 and the second space S2 by the first thrust magnetic bearing 50, it is possible to prevent the refrigerant delivered to the second space S2 through the rotor passage 93 by the pump function of the rotor passage 93 from flowing back to the first space S1 from between the stator 52 of the first thrust magnetic bearing 50 and the inner wall 10a of the housing 10 due to the close contact structure, and it is possible to prevent the refrigerant from flowing back to the first space S1 from the gap between the rotor 51 and the stator 52 of the first thrust magnetic bearing 50 due to the characteristics of the first thrust magnetic bearing 50. Therefore, the pressure of the second space S2 can be made higher than that of the first space S1. In this way, the pressure (pressure difference force) generated by the pressure difference between the first space S1 and the second space S2 can be used to pull the rotating shaft 30 to the other side in the axial direction. As a result, when the impeller 40 rotates and the rotating shaft 30 is pulled toward one axial direction, the rotating shaft 30 can be pulled toward the other axial direction by utilizing the pulling force of the first thrust magnetic bearing 50, and the rotating shaft 30 can also be pulled toward the other axial direction by utilizing the pressure difference force between the first space S1 and the second space S2. Therefore, by utilizing the pressure difference between the first space S1 and the second space S2, the pulling force of the first thrust magnetic bearing 50 can be reduced accordingly. As a result, the first thrust magnetic bearing 50 can be miniaturized. Since the pulling force of the first thrust magnetic bearing 50 can be reduced, the power consumption of the first thrust magnetic bearing 50 can be reduced.

[0094] <Second embodiment>

[0095] Reference Figure 6 , a second embodiment of the compressor 100 will be described. In the second embodiment, the shape of the rotor passage 93 is different from that of the first embodiment. Hereinafter, the differences from the first embodiment will be mainly described.

[0096] like Figure 6 As shown, the intermediate passage Z2 is composed of a rotor passage 93. The rotor passage 93 includes a first rotor passage portion 93A and a second rotor passage portion 93B. The first rotor passage portion 93A and the second rotor passage portion 93B extend in directions perpendicular to each other. The first rotor passage portion 93A extends parallel to the axial direction. A first rotor opening portion 93a communicating with the first space S1 is provided on the other axial direction side of the first rotor passage portion 93a. The second rotor passage portion 93B extends in the radial direction. The radial inner side Q1 of the second rotor passage portion 93B is communicated with the axial one direction side of the first rotor passage portion 93A. A second rotor opening portion 93b communicating with the second space S2 is provided on the radial outer side Q2 of the second rotor passage portion 93B.

[0097] As described above, by forming the rotor passage 93 into a substantially L-shape by the first rotor passage portion 93A and the second rotor passage portion 93B, the second rotor opening 93b can be formed at the radially outermost portion of the rotor 51. As a result, the efficiency of pumping the refrigerant by the pump function of the rotor passage 93 can be improved.

[0098] <Third Embodiment>

[0099] Reference Figure 7 A third embodiment of the compressor 100 will be described. In the third embodiment, the shape of the intermediate passage Z2 is different from that of the first embodiment. Hereinafter, the differences from the first embodiment will be mainly described.

[0100] like Figure 7 As shown, the intermediate passage Z2 includes a rotor passage 93 and a stator passage 94. The rotor passage 93 and the stator passage 94 are each substantially L-shaped. The rotor passage 93 communicates with the first space S1 via a first rotor opening 93a. The stator passage 94 communicates with the second space S2 via a second stator opening 94b.

[0101] The stator passage 94 is a hole provided on the stator 52 and penetrating the stator 52. In the third embodiment, the stator passage 94 is provided in the second stator portion 53b. The stator passage 94 is provided on the radially outer side Q2 of the rotor passage 93. The stator passage 94 includes a first stator opening portion 94a and a second stator opening portion 94b. The first stator opening portion 94a and the second stator opening portion 94b respectively connect the inside and the outside of the stator passage 94. The second stator opening portion 94b is located at a position closer to the radially outer side Q2 than the first stator opening portion 94a. The second stator opening portion 94b is located at a position closer to one direction side in the axial direction than the first stator opening portion 94a.

[0102] In terms of axial position, the first stator opening 94a is located at the same position as the second rotor opening 93b of the rotor passage 93. When the rotating shaft 30 rotates, the second rotor opening 93b rotates together with the rotating shaft 30, and the second rotor opening 93b faces the first stator opening 94a, thereby connecting the rotor passage 93 to the stator passage 94. The stator passage 94 is connected to the second space S2 via the second stator opening 94b.

[0103] The refrigerant flowing through the first passage Z1 flows into the rotor passage 93 through the communication between the rotor passage 93 and the stator passage 94, and is then sent to the stator passage 94. As a result, the stator 52 can be cooled by the refrigerant flowing in the stator passage 94.

[0104] <Fourth embodiment>

[0105] Reference Figure 8 and Fig. 9 , a fourth embodiment of the compressor 100 will be described. In the fourth embodiment, the structure for communicating the rotor passage 93 and the stator passage 94 is different from the third embodiment. Hereinafter, the differences from the third embodiment will be mainly described.

[0106] like Figure 8 and Fig. 9 As shown, the intermediate passage Z2 further includes a rotor groove 93c. The rotor groove 93c is provided on the outer periphery of the rotor 51. The rotor groove 93c is formed in an annular shape with the axis P of the rotating shaft 30 as the center. A second rotor opening 93b is formed in the rotor groove 93c. The rotor groove 93c is connected to the rotor passage 93 via the second rotor opening 93b.

[0107] A stator slot 94c is provided on the inner periphery of the stator 52. The stator slot 94c is formed in an annular shape with the axis P of the rotating shaft 30 as the center. A first stator opening 94a is formed in the stator slot 94c. The stator slot 94c is connected to the stator passage 94 via the first stator opening 94a. The rotor slot 93c is arranged radially inward Q1 relative to the stator slot 94c.

[0108] After the refrigerant flowing through the first passage Z1 flows into the rotor passage 93, it is transported to the stator passage 94 via the rotor groove 93c and the stator groove 94c. As a result, the stator 52 can be cooled by the refrigerant flowing in the stator passage 94. By providing the rotor groove 93c and the stator groove 94c, the rotor passage 93 and the stator passage 94 can be kept in a state of communication, so the refrigerant can stably flow to the rotor passage 93 or the stator passage 94. As a result, since the refrigerant can stably flow, the vibration of the rotating shaft 30 can be effectively suppressed.

[0109] The above embodiments and variations are described, but it should be understood that various changes can be made to their forms and specific circumstances without departing from the spirit and scope of the claims (for example, the following (1) and (2)). As long as the functions of the objects of the present disclosure are not affected, the above embodiments, variations, and other embodiments can also be appropriately combined or replaced.

[0110] <Modification of the close contact structure>

[0111] (1) A modified example of the above-mentioned close contact structure is described. In the first to fourth embodiments, the stator 52 is in close contact with the inner wall 10a of the housing 10 in order to divide the space in the housing 10 into the first space S1 and the second space S2 (see Figure 4). However, the present invention is not limited thereto. A gap filling material such as metal, resin, etc. may be arranged between the stator 52 and the inner wall 10a of the housing 10, so that the stator 52 and the inner wall 10a of the housing 10 are closely attached to each other through the gap filling material, thereby dividing the space in the housing 10 into the first space S1 and the second space S2.

[0112] <Modification of the First Passage of the Refrigerant Passage>

[0113] (2) A modification of the first passage Z1 of the refrigerant passage Z is described. In the first to fourth embodiments, the first passage Z1 leads from the first connecting hole 91 to the first space S1, and is connected to the intermediate passage Z2 in the first space S1 through the bearing 81a. However, the present invention is not limited to this. It can also be configured as follows: a connecting hole that connects the first space S1 and the outside of the housing 10 is formed on the second housing portion 12 of the housing 10, and the first passage Z1 leads from the connecting hole to the first space S1, and is connected to the intermediate passage Z2 in the first space S1.

[0114] - Industrial Applicability -

[0115] In summary, the present disclosure is useful for a rotor of a thrust magnetic bearing, a thrust magnetic bearing, and a rotary fluid machine.

[0116] - Explanation of symbols -

[0117] 20 Motor

[0118] 30 Rotation axis

[0119] 50 First thrust magnetic bearing (thrust magnetic bearing)

[0120] 51 Rotor

[0121] 93 Rotor Passage

[0122] Z Refrigerant passage

Claims

1. A rotor (51) of a thrust magnetic bearing (50), wherein the thrust magnetic bearing (50) supports a rotating shaft (30) in an axial direction, and the rotating shaft (30) is driven to rotate by a motor (20), characterized in that: The rotor (51) is engaged with the rotating shaft (30), and the rotor (51) is a component separate from the rotating shaft (30). The rotor (51) is provided with a rotor passage (93), which passes through the rotor (51) and is a part of a refrigerant passage (Z) for conveying refrigerant to the motor (20). The rotor passage (93) includes an opening (93b) provided on one side in the axial direction and an opening (93a) provided on the other side in the axial direction. The opening (93b) on the one direction side is located radially outward (Q2) relative to the opening (93a) on the other direction side. The rotor (51) is located on the other side of the axial direction relative to the motor (20).

2. The rotor of the thrust magnetic bearing according to claim 1, characterized in that: The rotor passage (93) includes a first rotor passage portion (93A) and a second rotor passage portion (93B) extending in directions perpendicular to each other.

3. A thrust magnetic bearing, characterized in that: It comprises the rotor (51) as claimed in claim 1, and a stator (52) arranged opposite to the rotor (51).

4. The thrust magnetic bearing according to claim 3, characterized in that: The refrigerant passage (Z) includes a stator passage (94) provided on the stator (52).

5. The thrust magnetic bearing according to claim 4, characterized in that: The refrigerant passage (Z) includes a rotor groove (93c) formed in an annular shape along the outer circumference of the rotor (51).

6. A rotary fluid machine, characterized in that: It comprises the thrust magnetic bearing (50) according to claim 3, the motor (20), and the rotating shaft (30).

7. The rotary fluid machine according to claim 6, characterized in that: The rotary fluid machine includes a bearing (81a) that rotatably supports the rotary shaft (30). The bearing (81a) is arranged on the refrigerant passage (Z).

8. The rotary fluid machine according to claim 6, characterized in that: The rotary fluid machine includes a grounding member (83) for grounding the rotating shaft (30). The grounding member (83) is opposite to the axial center portion (30a) of the rotating shaft (30).

9. The rotary fluid machine according to claim 6, characterized in that: The motor (20) is located on one side of the axial direction relative to the thrust magnetic bearing (50). A first space (S1) exists on the other side of the axial direction relative to the thrust magnetic bearing (50). A second space (S2) exists on one side of the axial direction relative to the thrust magnetic bearing (50). By sending the refrigerant to the second space (S2) through the rotor passage (93), the pressure of the second space (S2) becomes higher than the pressure of the first space (S1).

10. The rotary fluid machine according to claim 9, characterized in that: The rotary fluid machine comprises a housing (10) for accommodating the thrust magnetic bearing (50). The thrust magnetic bearing (50) divides the space inside the housing (10) into the first space (S1) and the second space (S2).

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