Rotating electric machine rotor and rotating electric machine

Abstract

This rotating electric machine rotor comprises: a magnet; a metal sleeve which is formed of a metal material and is provided so as to cover the magnet; and at least one non-metal sleeve which is formed of a non-metal material and is attached to an outer peripheral surface of the metal sleeve. The at least one non-metal sleeve is formed with a gap so as to partially expose the outer peripheral surface of the metal sleeve.

Description

Rotor for rotating electric machine and rotating electric machine

[0001] This application claims priority to Japanese Patent Application No. 2023-222324, filed on December 28, 2023, with the Japan Patent Office, the contents of which are incorporated herein by reference.

[0002] Patent Document 1 discloses a motor rotor designed to easily and efficiently attach a CFRP protective tube to the outer periphery of a permanent magnet attached to a rotor shaft. In this rotor, a permanent magnet is attached to the outer periphery of the rotor shaft, and a CFRP protective tube covers the entire outer periphery of the permanent magnet. A hollow chamber and a flow hole are formed in the rotor shaft, and the rotor shaft thermally shrinks when liquid nitrogen or the like is circulated inside. When the rotor shaft shrinks to a smaller diameter, a protective tube is fitted onto the rotor shaft and positioned on the outer periphery of the permanent magnet.

[0003] Japanese Patent Application Laid-Open No. 2017-50925

[0004] In rotors for rotating electrical machines, when a metal sleeve is provided to cover the magnet to prevent the magnet from scattering if the magnet is damaged, the metal sleeve has the advantage of being strong enough to prevent the magnet from scattering, but it is prone to heat generation due to eddy currents and expansion. When the metal sleeve expands due to heat generation, gaps are created inside the metal sleeve, which raises concerns about increased vibration of the rotor when it rotates.

[0005] In view of the above circumstances, at least one embodiment of the present disclosure aims to provide a rotor for a rotating electric machine and a rotating electric machine that can suppress magnet scattering using a metal sleeve and can suppress an increase in rotor vibration caused by thermal expansion of the metal sleeve.

[0006] In order to achieve the above object, a rotor for a rotating electric machine according to at least one embodiment of the present disclosure is a rotor for a rotating electric machine comprising: a magnet; a metal sleeve made of a metal material and arranged to cover the magnet; and at least one non-metallic sleeve made of a non-metallic material and attached to the outer circumferential surface of the metal sleeve, wherein a gap is formed in the at least one non-metallic sleeve so as to partially expose the outer circumferential surface of the metal sleeve.

[0007] According to at least one embodiment of the present disclosure, a rotor for a rotating electric machine and a rotating electric machine are provided that can suppress magnet scattering using a metal sleeve and can suppress an increase in rotor vibration caused by thermal expansion of the metal sleeve.

[0008] 1 is a schematic cross-sectional view showing a portion of a motor 2 according to an embodiment of the rotating electric machine of the present disclosure. FIG. 2 is a schematic cross-sectional view showing the flow of cooling gas in the cross section shown in FIG. 1. FIG. 3 is a schematic cross-sectional view showing a portion of a motor 2 according to another embodiment. FIG. 4 is a schematic cross-sectional view showing a portion of a motor 2 according to another embodiment. FIG. 5 is a schematic cross-sectional view for explaining an example of a magnet 14 divided in the axial direction. FIG. 6 is a schematic diagram showing an example of the general configuration of a steam compressor 50 to which the motor 2 shown in each of FIGS. 1 to 4 can be applied.

[0009] Several embodiments of the present disclosure will be described below with reference to the accompanying drawings. However, the dimensions, materials, shapes, relative arrangements, etc. of components described as embodiments or shown in the drawings are merely illustrative examples and are not intended to limit the scope of the invention. For example, expressions expressing relative or absolute arrangements, such as "in a certain direction," "along a certain direction," "parallel," "orthogonal," "center," "concentric," or "coaxial," not only strictly express such arrangements, but also express relative displacements with a tolerance or angle or distance to the extent that the same function is achieved. For example, expressions expressing the equality of things, such as "same," "equal," and "homogeneous," not only express strict equality, but also express tolerance or differences to the extent that the same function is achieved. For example, expressions expressing shapes such as a square or cylindrical shape not only express shapes such as a square or cylindrical shape in the strict geometric sense, but also express shapes including concave and convex portions, chamfered portions, etc., to the extent that the same effect is achieved. On the other hand, the expressions "comprise," "include," "have," "includes," or "have" of one element are not exclusive expressions that exclude the presence of other elements.

[0010] 1 is a schematic cross-sectional view showing a portion of a motor 2 according to an embodiment of a rotating electric machine of the present disclosure. As shown in FIG. 1, the motor 2 includes a rotor 4, a bearing device 8 that rotatably supports the rotor 4, and a stator 10.

[0011] The rotor 4 includes a shaft 12, a magnet 14, end rings 15 and 16, a metal sleeve 18, and a CFRP sleeve 20 as a non-metallic sleeve.

[0012] In the following description, unless otherwise specified, the term "axial direction" refers to the axial direction of the rotor 4 (i.e., the axial direction of each of the shaft 12, magnet 14, end rings 15 and 16, metal sleeve 18, and CFRP sleeve 20), the term "radial direction" refers to the radial direction of the rotor 4 (i.e., the radial direction of each of the shaft 12, magnet 14, end rings 15 and 16, metal sleeve 18, and CFRP sleeve 20), and the term "circumferential direction" refers to the circumferential direction of the rotor 4 (i.e., the circumferential direction of each of the shaft 12, magnet 14, end rings 15 and 16, metal sleeve 18, and CFRP sleeve 20), unless otherwise specified.

[0013] The shaft 12 is made of a metal material and extends along the rotation axis O of the rotor 4 .

[0014] The magnet 14 is, for example, a permanent magnet, and is attached to the outer circumferential surface 12 a of the shaft 12. In the illustrated exemplary embodiment, the magnet 14 has a cylindrical shape and is arranged concentrically with the shaft 12, with the inner circumferential surface 14 a of the magnet 14 fixed to the outer circumferential surface 12 a of the shaft 12.

[0015] End ring 15 is attached to the outer circumferential surface 12 a of shaft 12 on one axial end side of magnet 14, and end ring 16 is attached to the outer circumferential surface 12 a of shaft 12 on the other axial end side of magnet 14. In the illustrated exemplary embodiment, end rings 15, 16 are each arranged concentrically with shaft 12, and inner circumferential surfaces 15 a of end ring 15 and 16 a of end ring 16 are fixed to the outer circumferential surface 12 a of shaft 12.

[0016] The metal sleeve 18 is made of a metal material such as heat-resistant steel, and is attached to the outer circumferential surface 14b of the magnet 14. The metal sleeve 18 has a cylindrical shape and is arranged concentrically with the shaft 12, with the inner circumferential surface 18a of the metal sleeve 18 fixed to the outer circumferential surface 14b of the magnet 14. In the illustrated exemplary embodiment, the metal sleeve 18 is provided so as to cover the outer circumferential surface 15b of the end ring 15, the outer circumferential surface 14b of the magnet 14, and the outer circumferential surface 16b of the end ring 16.

[0017] The CFRP sleeve 20 is made of carbon fiber reinforced plastics (CFRP) and is attached to the outer peripheral surface 18b of the metal sleeve 18. The CFRP sleeve 20 has a cylindrical shape and is disposed concentrically with the shaft 12, with the inner peripheral surface 20a of the CFRP sleeve 20 fixed to the outer peripheral surface 18b of the metal sleeve 18.

[0018] A plurality of voids 24 are formed in the CFRP sleeve 20 so as to partially expose the outer peripheral surface 18b of the metal sleeve 18. In other words, the plurality of voids 24 are formed in the CFRP sleeve 20 so that, when each of the plurality of voids 24 is viewed radially from the outside in the radial direction, the outer peripheral surface 18b of the metal sleeve 18 can be seen through each of the plurality of voids 24. In the illustrated exemplary form of the outer peripheral surface 18b of the metal sleeve 18, each of the plurality of voids 24 is a through-hole that penetrates the CFRP sleeve 20 in the radial direction, and the plurality of voids 24 are formed at different positions from each other in the axial direction. Furthermore, in the illustrated exemplary form, each of the plurality of voids 24 is formed in a partial range in the circumferential direction.

[0019] Here, we will explain the effects of the rotor 4 of the motor 2. With the rotor 4, the metal sleeve 18 that covers the magnet 14 can prevent the magnet 14 from scattering if the magnet 14 is damaged. Furthermore, by attaching a CFRP sleeve 20 to the outer circumferential surface 18b of the metal sleeve 18, the CFRP sleeve 20 can suppress thermal expansion of the metal sleeve 18.

[0020] If a CFRP sleeve 20 with a lower thermal conductivity than the metal sleeve 18 were attached to the outer peripheral surface 18b of the metal sleeve 18, heat would easily build up inside the CFRP sleeve 20, making it difficult to suppress temperature increases in the magnets 14 and the metal sleeve 18 unless some ingenuity is put into place. In contrast, in the rotor 4, the CFRP sleeve 20 has a gap 24 formed therein that partially exposes the outer peripheral surface 18b of the metal sleeve 18. As shown by arrow f in FIG. 2 , this allows cooling gas (e.g., air) flowing axially between the rotor 4 and the stator 10 to be supplied to the outer peripheral surface 18b of the metal sleeve 18 through the gap 24, thereby cooling the metal sleeve 18. Therefore, the metal sleeve 18 can prevent the magnets 14 from flying away, and can also suppress increased vibration of the rotor 4 due to thermal expansion of the metal sleeve 18.

[0021] In some embodiments, for example, as shown in Figure 1, where t is the thickness of the CFRP sleeve 20 and d is the size of each void 24 in the axial direction, d > t / 5 may be satisfied. In other words, d may be greater than the value obtained by dividing t by 5.

[0022] If the size of the gaps 24 in the axial direction is excessively small, convective heat transfer of the cooling gas flowing in the axial direction becomes difficult, but with the rotor 4, by providing gaps 24 that satisfy d > t / 5, the flow of cooling gas along the outer peripheral surface of the CFRP sleeve 20 flows into the gaps 24, generating vortices and improving the heat transfer coefficient of convective heat transfer, as shown in Figure 2. Therefore, the metal sleeve 18 can be effectively cooled by the cooling gas flowing in the axial direction.

[0023] Fig. 3 is a schematic cross-sectional view showing a part of a motor 2 according to another embodiment. In the components of the motor 2 shown in Fig. 3, the same reference numerals as those of the components of the motor 2 shown in Fig. 1 indicate the same components as those of the motor 2 shown in Fig. 1 unless otherwise specified, and the description thereof will be omitted.

[0024] The motor 2 shown in FIG. 3 includes a first sleeve 20A and a second sleeve 20B as the CFRP sleeve 20.

[0025] The first sleeve 20A is made of carbon fiber reinforced plastic and is attached to the outer peripheral surface 18b of the metal sleeve 18. The first sleeve 20A has a cylindrical shape and is arranged concentrically with the shaft 12. An inner peripheral surface 20Aa of the first sleeve 20A is fixed to the outer peripheral surface 18b of the metal sleeve 18.

[0026] The second sleeve 20B is made of carbon fiber reinforced plastic and is attached to the outer peripheral surface 18b of the metal sleeve 18 with a gap in the axial direction from the first sleeve 20A. The second sleeve 20B has a cylindrical shape and is arranged concentrically with the shaft 12, with the inner peripheral surface 20Ba of the second sleeve 20B fixed to the outer peripheral surface 18b of the metal sleeve 18.

[0027] In the embodiment shown in Fig. 3, a gap 24 is formed between the first sleeve 20A and the second sleeve 20B, which partially exposes the outer peripheral surface 18b of the metal sleeve 18. That is, the gap 24 is formed between the first sleeve 20A and the second sleeve 20B so that the outer peripheral surface 18b of the metal sleeve 18 can be seen through the gap 24 when viewed radially from the outside in the radial direction. The gap 24 is formed over the entire circumferential direction between the first sleeve 20A and the second sleeve 20B. The gap 24 is formed in a range including a center position Pc of the metal sleeve 18 in the axial direction (the range indicated by arrow d in Fig. 3).

[0028] The rotor 4 shown in FIG. 3 may be manufactured by cooling the portion of the rotor 4 excluding the first sleeve 20A and the second sleeve 20B (an assembly including the shaft 12, the magnets 14, the end rings 15, 16, and the metal sleeve 18) to a temperature lower than that of the first sleeve 20A and the second sleeve 20B, and then attaching the first sleeve 20A and the second sleeve 20B to the assembly. That is, the rotor 4 shown in FIG. 3 may be manufactured by cool-fitting both axial ends of the assembly including the shaft 12, the magnets 14, the end rings 15, 16, and the metal sleeve 18 into the first sleeve 20A and the second sleeve 20B, respectively. Alternatively, the rotor 4 shown in FIG. 3 may be manufactured by press-fitting both axial ends of the assembly including the shaft 12, the magnets 14, the end rings 15, 16, and the metal sleeve 18 into the first sleeve 20A and the second sleeve 20B, respectively.

[0029] According to the rotor 4 shown in Figure 3, a gap 24 is formed between the first sleeve 20A and the second sleeve 20B, and there is no need to provide radially penetrating through holes in each of the first sleeve 20A and the second sleeve 20B to cool the metal sleeve 18. This makes it possible to prevent a decrease in the strength of the first sleeve 20A and the second sleeve 20B and to prevent an increase in processing costs.

[0030] 3, in consideration of the fact that the problem of thermal expansion is likely to occur at the axial center position Pc of the metal sleeve 18, the gap 24 is provided in a range including the axial center position Pc of the metal sleeve 18. This makes it possible to effectively cool the range including the axial center position Pc of the metal sleeve 18, and effectively suppress an increase in vibration of the rotor 4 due to thermal expansion of the metal sleeve 18.

[0031] Fig. 4 is a schematic cross-sectional view showing a part of a motor 2 according to another embodiment. In the components of the motor 2 shown in Fig. 4, the same reference numerals as those of the components of the motor 2 shown in Fig. 3 indicate the same components as those of the motor 2 shown in Fig. 3 unless otherwise specified, and the description thereof will be omitted.

[0032] The rotor 4 shown in Fig. 4 differs from the rotor 4 shown in Fig. 3 in that an annular protrusion 19 that protrudes radially outward is formed on the outer circumferential surface 18b of the metal sleeve 18. The protrusion 19 is disposed between the first sleeve 20A and the second sleeve 20B.

[0033] 4 , the first sleeve 20A is positioned in the axial direction by contacting the end face 20Ab of the first sleeve 20A facing the second sleeve 20B with the side face 19a of the protrusion 19 on the first sleeve 20A side, and the second sleeve 20B is positioned in the axial direction by contacting the end face 20Bb of the second sleeve 20B facing the first sleeve 20A with the side face 19b of the protrusion 19 on the second sleeve 20B side. In other words, the protrusion 19 functions as a positioning portion that determines the axial positions of the first sleeve 20A and the second sleeve 20B. This facilitates production management of the rotor 4.

[0034] Furthermore, if the thickness of the metal sleeve 18 in the axial range S1 where the first sleeve 20A is provided is defined as t1, the thickness of the metal sleeve 18 in the axial range S2 where the second sleeve 20B is provided is defined as t2, and the thickness of the metal sleeve 18 in the axial range S3 where the gap 24 is provided is defined as t3, then t3 is greater than both t1 and t2. That is, the relationships t3 > t1 and t3 > t2 are satisfied.

[0035] Since the fastening strength of the magnet 14 is likely to be locally low in the range S3 where the axial gap 24 is provided, by making t3 larger than both t1 and t2 as described above, it is possible to suppress the reduction in the fastening strength of the magnet 14 in the range S3 where the axial gap 24 is provided.

[0036] In some embodiments, in the rotor 4 of the motor 2 shown in each of Figures 1 to 4, the magnet 14 may be composed of multiple magnet members 21 (see Figure 5) divided in the axial direction. In the example shown in Figure 5, the multiple magnet members 21 are arranged in the axial direction, and each of the multiple magnet members 21 is formed in an annular shape. Each of the multiple magnet members 21 is arranged concentrically with the shaft 12, and the inner circumferential surface 21a of the magnet member 21 is fixed to the outer circumferential surface 12a of the shaft 12.

[0037] Dividing the magnet 14 in the axial direction can suppress an increase in the amount of heat generated by the magnet 14, but tends to increase the amount of heat generated by the metal sleeve 18. However, in the rotors 4 shown in each of Figures 1 to 4, the metal sleeve 18 can be effectively cooled by the gap 24, so when the magnet 14 is divided in the axial direction, the temperature rise of the magnet 14 and the metal sleeve 18 can be effectively suppressed.

[0038] Fig. 6 is a schematic diagram showing an example of the general configuration of a steam compressor 50 to which the motor 2 shown in each of Figs. 1 to 4 can be applied. The exemplary steam compressor 50 shown in Fig. 6 includes the motor 2 and multiple compressors (two compressors 52, 54 in the illustrated example) driven by the motor 2, with an impeller 52a of the compressor 52 connected to one end of the shaft 12 of the rotor 4 of the motor 2, and an impeller 54a of the compressor 54 connected to the other end of the shaft 12 of the rotor 4.

[0039] The compressor 52 compresses the steam by rotating an impeller 52 a due to the driving force of the motor 2 , and the compressor 54 compresses the steam by rotating an impeller 54 a due to the driving force of the motor 2 .

[0040] 6, the steam compressed by the compressors 52, 54 and the motor cooling gas (air in the illustrated example) that cools the motor 2 are different types of gas. In this case, if the pressure of the motor cooling gas is increased to cool the motor 2 and a large amount of motor cooling gas is circulated through the motor 2, there is a possibility that the motor cooling gas will leak into the main flow (steam flow) on the compressors 52, 54 side, and therefore there is a limit to the pressure and flow rate of the motor cooling gas used to cool the motor 2.

[0041] In this regard, by applying the motor 2 shown in each of Figures 1 to 4 to the motor 2 of the steam compressor 50, the rotor 4 of the motor 2 can be effectively cooled while suppressing an increase in the pressure and flow rate of the motor cooling gas, and the motor 2 can be used preferably.

[0042] 6, the motor cooling gas that cools the rotor 4 of the motor 2 and the cooling gas that cools the bearing device 8 are the same gas (air in the illustrated example). In such a configuration, when cooling gas is supplied to the rotor 4 and the bearing device 8 from a common cooling gas supply source, the proportion of the flow rate of cooling gas supplied to the rotor 4 is reduced by the amount of cooling gas supplied to the bearing device 8, and therefore there is a tendency to require cooling the rotor 4 with a small amount of cooling gas.

[0043] In this regard, by applying the motor 2 shown in each of Figures 1 to 4 to the motor 2 of the steam compressor 50, the rotor 4 of the motor 2 can be effectively cooled with a small amount of motor cooling gas, and therefore the motor 2 can be used preferably.

[0044] The present disclosure is not limited to the above-described embodiments, but also includes modifications to the above-described embodiments and appropriate combinations of these modifications.

[0045] For example, the motor 2 shown in each of Figures 1 to 4 may be applied to a motor that drives a compressor in each stage of a multi-stage vapor compressor, or to a motor that drives a compressor in a heat pump. In a heat pump, the heat medium compressed by the compressor and the cooling gas (e.g., air) that cools the motor that drives the compressor are different types of gas. As with the vapor compressor described above, there are limits to the pressure and flow rate of the cooling gas used to cool the motor 2. Therefore, by applying the motor 2 shown in each of Figures 1 to 4 to a motor that drives a heat pump compressor, the rotor 4 of the motor 2 can be effectively cooled with a small amount of motor cooling gas, allowing the motor 2 to be used optimally.

[0046] Furthermore, the rotor 4 shown in each of FIGS. 1 to 4 may be applied to the rotor of a generator, and can be used as a rotor for a rotating electric machine (motor or generator).

[0047] Furthermore, in the rotor 4 shown in each of Figures 1 to 4, a CFRP sleeve 20 is shown as an example of a non-metallic sleeve attached to the outer peripheral surface of the metal sleeve 18, but the non-metallic sleeve attached to the outer peripheral surface of the metal sleeve 18 may be made of other materials including resin, such as fiber reinforced plastic other than CFRP.

[0048] Furthermore, although the rotor 4 shown in each of Figures 1 to 4 includes the shaft 12 and the cylindrical magnet 14 attached to the outer peripheral surface 12a of the shaft 12, it is not necessary for the shaft 12 to be provided inside the magnet 14, and the rotor 4 may include, for example, a solid cylindrical magnet 14, and the above-mentioned metal sleeve 18 and CFRP sleeve 20.

[0049] Furthermore, although the CFRP sleeve 20 shown in FIG. 1 has a plurality of voids 24 formed therein so as to partially expose the outer peripheral surface 18b of the metal sleeve 18, the number of voids 24 formed in the CFRP sleeve 20 so as to partially expose the outer peripheral surface 18b of the metal sleeve 18 may be one.

[0050] The contents described in each of the above embodiments can be understood, for example, as follows.

[0051] [1] A rotor for a rotating electric machine (e.g., rotor 4 described above) according to at least one embodiment of the present disclosure comprises: a magnet (e.g., magnet 14 described above); a metal sleeve (e.g., metal sleeve 18 described above) made of a metal material and arranged to cover the magnet; and at least one non-metallic sleeve (e.g., CFRP sleeve 20 described above, first sleeve 20A, second sleeve 20B described above) made of a non-metallic material and attached to the outer circumferential surface of the metal sleeve (e.g., outer circumferential surface 18b described above), wherein a gap (e.g., gap 24 described above) is formed in the at least one non-metallic sleeve so as to partially expose the outer circumferential surface of the metal sleeve.

[0052] According to the rotor for a rotating electric machine described in [1] above, the metallic sleeve covering the magnet can prevent the magnet from scattering if the magnet is damaged. Furthermore, by attaching at least one non-metallic sleeve to the outer peripheral surface of the metallic sleeve, the non-metallic sleeve can suppress thermal expansion of the metallic sleeve. However, attaching a non-metallic sleeve to the outer peripheral surface of the metallic sleeve tends to trap heat inside the non-metallic sleeve, making it difficult to suppress temperature increases of the magnet and the metallic sleeve without some ingenuity. However, in the rotor for a rotating electric machine described in [1] above, at least one non-metallic sleeve has a gap formed in it that partially exposes the outer peripheral surface of the metallic sleeve. This allows cooling gas to be supplied to the outer peripheral surface of the metallic sleeve through the gap to cool the metallic sleeve. Therefore, the metallic sleeve can prevent the magnet from scattering and suppress increased rotor vibration due to thermal expansion of the metallic sleeve.

[0053] [2] In some embodiments, in the rotor for a rotating electric machine described in [1] above, when the thickness of the non-metallic sleeve is t0 and the size of the gap in the axial direction of the rotor is d, d>t0 / 5 is satisfied.

[0054] If the size of the gap in the axial direction is too small, convective heat transfer of the cooling gas flowing in the axial direction is difficult to achieve. However, according to the rotor for a rotating electric machine described in [2] above, by providing a gap that satisfies d > t / 5, the flow of cooling gas along the outer circumferential surface of the non-metallic sleeve flows into the gap, generating vortices and improving the heat transfer coefficient of convective heat transfer. Therefore, the cooling gas flowing in the axial direction can effectively cool the metallic sleeve.

[0055] [3] In some embodiments, in the rotor for a rotating electric machine described in [1] or [2] above, the at least one non-metallic sleeve includes: a non-metallic first sleeve (e.g., the above-mentioned first sleeve 20A) attached to the outer circumferential surface of the metal sleeve; and a non-metallic second sleeve (e.g., the above-mentioned second sleeve 20B) attached to the outer circumferential surface of the metal sleeve and spaced apart from the non-metallic first sleeve in the axial direction of the rotor, and the gap is formed between the non-metallic first sleeve and the non-metallic second sleeve.

[0056] According to the rotor for a rotating electric machine described in [3] above, compared to the case where a through hole that penetrates radially through the non-metallic sleeve is provided as the void, there is no need to provide a through hole in each of the non-metallic first sleeve and the non-metallic second sleeve, so it is possible to suppress a decrease in the strength of the non-metallic first sleeve and the non-metallic second sleeve and to reduce processing costs.

[0057] [4] In some embodiments, in the rotor for a rotating electric machine described in [3] above, the gap is formed between the non-metallic first sleeve and the non-metallic second sleeve over the entire circumferential direction of the rotor.

[0058] According to the rotor for a rotating electric machine described in the above [4], the metal sleeve can be cooled effectively.

[0059] [5] In some embodiments, in the rotor for a rotating electric machine described in [3] or [4] above, the gap is formed in a range including the center position of the metal sleeve in the axial direction (for example, the position Pc described above) (for example, the range corresponding to the arrow d described above).

[0060] According to the rotor for a rotating electric machine described in [5] above, in view of the fact that the central position of the metal sleeve in the axial direction is prone to problems of thermal expansion, the gap is provided in a range including the central position of the metal sleeve in the axial direction, thereby effectively cooling the range including the central position of the metal sleeve in the axial direction, and effectively suppressing an increase in vibration of the rotor due to thermal expansion of the metal sleeve.

[0061] [6] In some embodiments, in the rotor for a rotating electric machine described in any of [3] to [5] above, a protrusion (e.g., the above-mentioned protrusion 19) is formed on the outer peripheral surface of the metal sleeve, protruding radially outward from the rotor, and the protrusion is located between the non-metallic first sleeve and the non-metallic second sleeve.

[0062] According to the rotor for a rotating electric machine described in [6] above, by bringing the non-metallic first sleeve and the non-metallic second sleeve into contact with both end faces of the protrusion in the axial direction, it is possible to position the non-metallic first sleeve and the non-metallic second sleeve in the axial direction, making it easier to manage the manufacturing of the rotor for a rotating electric machine.

[0063] [7] In some embodiments, in the rotor for a rotating electric machine according to the above [6], the protrusion is formed over the entire circumferential direction of the rotor.

[0064] According to the rotor for a rotating electric machine described in [7] above, by bringing the non-metallic first sleeve and the non-metallic second sleeve into contact with both end faces of the protrusion in the axial direction, it becomes possible to position the non-metallic first sleeve and the non-metallic second sleeve in the axial direction, making it easier to manage the manufacturing of the rotor for a rotating electric machine.

[0065] [8] In some embodiments, in the rotor for a rotating electric machine described in [6] or [7] above, the end face of the non-metallic first sleeve (e.g., the end face 20Ab described above) is in contact with one side face of the protrusion in the axial direction (e.g., the side face 19a described above), and the end face of the non-metallic second sleeve (e.g., the end face 20Bb described above) is in contact with the other side face of the protrusion in the axial direction (e.g., the side face 19b described above).

[0066] According to the rotor for a rotating electric machine described in [8] above, it is possible to position the first non-metallic sleeve and the second non-metallic sleeve in the axial direction, which makes it easier to manage the manufacturing of the rotor for a rotating electric machine.

[0067] [9] In some embodiments, in the rotor for a rotating electric machine described in any of [3] to [8] above, if the thickness of the metal sleeve in the range in the axial direction where the non-metallic first sleeve is provided (e.g., the above-mentioned range S1) is t1, the thickness of the metal sleeve in the range in the axial direction where the non-metallic second sleeve is provided (e.g., the above-mentioned range S2) is t2, and the thickness of the metal sleeve in the range in the axial direction where the gap is provided (e.g., the above-mentioned range S3) is t3, t3 is greater than both t1 and t2.

[0068] Since the fastening strength of the magnet is likely to be locally low in the area where the axial gap is provided, by making t3 larger than both t1 and t2 as described in [9] above, it is possible to suppress the reduction in the fastening strength of the magnet in the area where the axial gap is provided.

[0069]

[10] In some embodiments, in the rotor for a rotating electric machine described in [1] or [2] above, the non-metallic sleeve has a through hole (e.g., a through hole corresponding to the gap 24 in Figure 1) formed therein, which passes through the rotor in the radial direction, and the gap is the through hole.

[0070] According to the rotor for a rotating electric machine described in the above

[10] , the number of parts can be reduced compared to the rotor for a rotating electric machine described in the above [3].

[0071]

[11] In some embodiments, in the rotor for a rotating electric machine according to any one of the above [1] to

[10] , the metal sleeve is cold-fitted into the non-metallic sleeve.

[0072] According to the rotor for a rotating electric machine described in the above

[11] , the non-metallic sleeve can be easily fixed to the metallic sleeve.

[0073]

[12] In some embodiments, in the rotor for a rotating electric machine according to any one of the above [1] to

[11] , the non-metallic sleeve is made of a material containing resin.

[0074] According to the rotor for a rotating electric machine described in

[12] above, since no eddy currents are generated in the non-metallic sleeve, the thermal expansion of the metallic sleeve can be suppressed by the non-metallic sleeve while the thermal expansion of the non-metallic sleeve can be suppressed.

[0075]

[13] In some embodiments, in the rotor for a rotating electric machine according to the above

[12] , the non-metallic sleeve is made of carbon fiber reinforced plastic.

[0076] According to the rotor for a rotating electric machine described in

[13] above, since no eddy currents are generated in the non-metallic sleeve, the thermal expansion of the metallic sleeve can be suppressed by the lightweight, high-strength non-metallic sleeve, while the thermal expansion of the non-metallic sleeve can be suppressed.

[0077]

[14] A rotating electric machine according to at least one embodiment of the present disclosure includes the rotor for a rotating electric machine according to any one of [1] to

[13] above, and a stator (for example, the stator 10 described above).

[0078] According to the rotating electric machine described in

[14] above, since the rotating electric machine rotor described in any one of [1] to

[13] above is provided, scattering of magnets can be suppressed by the metal sleeve, and an increase in vibration of the rotor due to thermal expansion of the metal sleeve can be suppressed.

[0079] DESCRIPTION OF SYMBOLS 2 Motor 4 Rotor 8 Bearing device 10 Stator 12 Shaft 12a, 14b, 15b, 16b, 18b Outer circumferential surface 14 Magnet 14a, 15a, 16a, 18a, 20Aa, 20Ba, 20a, 21a Inner circumferential surface 15, 16 End ring 18 Metal sleeve 19 Protrusion 19a, 19b Side surface 20 CFRP sleeve 20A First sleeve 20Ab, 20Bb End surface 20B Second sleeve 21 Magnet member 24 Air gap 50 Steam compressor 52, 54 Compressor 52a, 54a Impeller

Claims

1. A rotor for a rotating electrical machine, comprising: a magnet; a metal sleeve made of a metal material and provided to cover the magnet; and at least one non-metal sleeve made of a non-metal material and mounted on an outer peripheral surface of the metal sleeve, wherein a gap is formed in the at least one non-metal sleeve so as to partially expose the outer peripheral surface of the metal sleeve.

2. The rotor for a rotating electrical machine according to claim 1, wherein, when a thickness of the non-metal sleeve is t0 and a size of the gap in an axial direction of the rotor is d, d > t0 / 5 is satisfied.

3. The rotor for a rotating electrical machine according to claim 1, wherein the at least one non-metal sleeve includes: a first non-metal sleeve mounted on the outer peripheral surface of the metal sleeve; and a second non-metal sleeve mounted on the outer peripheral surface of the metal sleeve and spaced apart from the first non-metal sleeve in the axial direction of the rotor, and the gap is formed between the first non-metal sleeve and the second non-metal sleeve.

4. The rotor for a rotating electrical machine according to claim 3, wherein the gap is formed over the entire circumferential direction of the rotor between the first non-metal sleeve and the second non-metal sleeve.

5. The rotor for a rotating electrical machine according to claim 4, wherein the gap is formed in a range including a central position of the metal sleeve in the axial direction.

6. The rotor for a rotating electrical machine according to claim 3, wherein a protruding portion protruding outward in a radial direction of the rotor is formed on the outer peripheral surface of the metal sleeve, and the protruding portion is located between the first non-metal sleeve and the second non-metal sleeve.

7. The rotor for a rotating electrical machine according to claim 6, wherein the protruding portion is formed over the entire circumferential direction of the rotor.

8. The rotor for a rotating electrical machine according to claim 6, wherein an end surface of the first non-metal sleeve contacts a side surface of one side of the protruding portion in the axial direction, and an end surface of the second non-metal sleeve contacts a side surface of the other side of the protruding portion in the axial direction.

9. For the rotor for a rotating electrical machine according to claim 3, when the thickness of the metal sleeve in the range where the non-metallic first sleeve is provided in the axial direction is t1, the thickness of the metal sleeve in the range where the non-metallic second sleeve is provided in the axial direction is t2, and the thickness of the metal sleeve in the range where the gap is provided in the axial direction is t3, t3 is greater than each of t1 and t2.

10. For the rotor for a rotating electrical machine according to claim 1, a through-hole penetrating in the radial direction of the rotor is formed in the non-metallic sleeve, and the gap is the through-hole.

11. For the rotor for a rotating electrical machine according to claim 1, the metal sleeve is shrink-fitted onto the non-metallic sleeve.

12. For the rotor for a rotating electrical machine according to claim 1, the non-metallic sleeve is made of a material containing resin.

13. For the rotor for a rotating electrical machine according to claim 12, the non-metallic sleeve is made of carbon fiber reinforced plastic.

14. A rotating electrical machine comprising the rotor for a rotating electrical machine according to any one of claims 1 to 13 and a stator.

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