Rotary electric machine and rotary electric machine system

Abstract

A rotary electric machine (101) comprises: a rotor (1) that can rotate about an axis (CA); a stator (2); a housing (3) accommodating the rotor and the stator; and a plurality of bearings (4A, 4B) that rotatably support the rotor with respect to the housing. The rotor has a shaft (10), a rotor core (11) connected to the shaft, and a rotor winding (12) wound around the rotor core. The stator has a stator core (21) connected to the housing, and a stator winding (22). The rotary electric machine further comprises at least one electrostatic shield (5) having a portion disposed between the rotor and the stator in a radial direction with respect to the axis. The at least one electrostatic shield is provided with a plurality of communication holes (50). The at least one electrostatic shield is electrically connected to either the stator core or the housing.

Description

Rotating electric machine and rotating electric machine system

[0001] The present disclosure relates to a rotating electric machine and a rotating electric machine system.

[0002] Japanese Patent Laid-Open Publication No. 01-144356 (Patent Document 1) describes a superconducting rotating electric machine in which the rotor's field winding is made of superconducting wire. The superconducting rotating electric machine is configured to cool the rotor and stator using a refrigerant that has higher insulating properties than gaseous helium at room temperature. The rotor's rotating shaft is rotatably supported by bearings on a stator frame.

[0003] Japanese Patent Application Publication No. 01-144356

[0004] In the rotating electric machine, stray capacitance occurs between the rotor and the stator core and stator winding. This creates a potential difference between the rotating shaft and the stator frame, which in turn creates a potential difference between the inner and outer rings of the bearings. This applies electrical stress to the bearings, posing a risk of damage to the bearings.

[0005] A primary object of the present disclosure is to provide a rotating electric machine that can reduce the risk of bearing damage while realizing cooling of both the rotor and the stator.

[0006] A rotating electric machine according to the present disclosure includes a rotor rotatable about an axis, a stator, a housing that accommodates the rotor and the stator, and a plurality of bearings that rotatably support the rotor relative to the housing. The rotor includes a shaft, a rotor core connected to the shaft, and a rotor winding wound around the rotor core. The stator includes a stator core connected to the housing and a stator winding. The rotating electric machine further includes at least one electrostatic shield having a portion disposed between the rotor and the stator in a radial direction relative to the axis. The at least one electrostatic shield has a plurality of communication holes that communicate between a first space located radially closer to the rotor than the at least one electrostatic shield and a second space located radially opposite the rotor relative to the at least one electrostatic shield. The plurality of bearings include an inner ring electrically connected to the shaft and an outer ring electrically connected to the housing. The at least one electrostatic shield is electrically connected to either the stator core or the housing.

[0007] A rotating electric machine system according to the present disclosure includes the rotating electric machine described above, a supply unit for supplying a cooling medium to the first flow path, and a recovery unit for recovering the cooling medium from the second flow path.

[0008] According to the present disclosure, it is possible to achieve cooling of both the rotor and the stator while reducing the risk of damage to the bearings.

[0009] FIG. 1 is a cross-sectional view showing a rotating electric machine and a rotating electric machine system according to a first embodiment. FIG. 2 is a partially enlarged cross-sectional view showing a rotor, a stator, and an electrostatic shield of a rotating electric machine according to the first embodiment. FIG. 3 is a cross-sectional view showing a rotating electric machine and a rotating electric machine system according to a second embodiment. FIG. 4 is a cross-sectional view showing a partially enlarged cross-sectional view showing a rotor, a stator, and an electrostatic shield of a rotating electric machine according to the third embodiment. FIG. 5 is a cross-sectional view showing a rotating electric machine according to a fourth embodiment. FIG. 6 is a partially enlarged cross-sectional view showing a rotor, a stator, and an electrostatic shield of a rotating electric machine according to the fourth embodiment. FIG. 7 is a cross-sectional view showing an example of a combination of rotating electric machines according to the first to fourth embodiments.

[0010] Hereinafter, embodiments of the present disclosure will be described with reference to the drawings. In the following, the same or corresponding parts will be denoted by the same reference numerals, and redundant description will not be repeated.

[0011] Embodiment 1. <Configuration of Rotating Electric Machine> The rotating electric machine according to embodiment 1 is a superconducting rotating electric machine. As shown in Fig. 1 , the rotating electric machine 101 according to embodiment 1 includes a rotor 1, a stator 2, a housing 3, a pair of bearings 4, an electrostatic shield 5, and a magnetic shield 6.

[0012] The rotor 1 is rotatable around an axis CA. Hereinafter, the radial direction and circumferential direction with respect to the axis CA of the rotor 1 will be simply referred to as the radial direction and the circumferential direction. The rotor 1 is disposed, for example, such that the axis CA is aligned horizontally. Note that FIG. 1 is a cross-sectional view taken along the axis CA.

[0013] The rotor 1 has a shaft 10, a rotor core 11, a rotor winding 12, a low-temperature damper 15, and a room-temperature damper 16. The rotor winding 12 is a superconducting winding. The low-temperature damper 15 is provided radially inward of the room-temperature damper 16. The rotor core 11 and the rotor winding 12 are provided radially inward of the low-temperature damper 15. The rotor 1 has an outer peripheral surface 13 that faces a stator core 21 of the stator 2 (described later) in the radial direction. The outer peripheral surface 13 is, for example, the outer peripheral surface of the room-temperature damper 16.

[0014] The shaft 10 extends along the axis CA. The shaft 10 includes a first shaft 10A and a second shaft 10B. The first shaft 10A and the second shaft 10B are arranged on the axis CA at a distance from each other. The first shaft 10A extends from the rotor core 11 to one side in the extension direction of the axis CA. The second shaft 10B extends from the rotor core 11 to the other side in the extension direction of the axis CA.

[0015] The rotor core 11 is a rotor core made of, for example, a magnetic material. However, the rotor core 11 may be made of, for example, a non-magnetic material such as stainless steel (SUS).

[0016] The rotor winding 12 is wound around the rotor core 11. The rotor winding 12 may be a so-called low-temperature superconducting winding. Preferably, the rotor winding 12 is a high-temperature superconducting winding whose superconducting transition temperature is equal to or higher than the liquefaction temperature of nitrogen gas (77 K).

[0017] The rotor 1 is provided with a plurality of slots 14 that accommodate a portion of the rotor winding 12. The plurality of slots 14 are arranged at intervals in the circumferential direction. Each of the plurality of slots 14 is provided radially inward of the low-temperature damper 15.

[0018] The low-temperature damper 15 is in communication with the room-temperature damper 16 via a communication hole (not shown). The room-temperature damper 16 forms the outer shell of the rotor 1. The room-temperature damper 16 is electrically connected to the shaft 10. The room-temperature damper 16 has the same potential as, for example, the shaft 10. The first shaft 10A and the second shaft 10B each have the same potential as the room-temperature damper.

[0019] The rotor 1 has a structure for supplying a cooling medium to the rotor windings 12 and a structure for discharging the cooling medium supplied to the rotor windings 12 to the outside of the rotor 1. Details of these structures will be described later.

[0020] The stator 2 is fixed to the housing 3. The stator 2 is disposed radially outward of the rotor winding 12. The stator 2 surrounds the entire circumference of the rotor winding 12 in the circumferential direction. The stator 2 has a stator core 21 and a stator winding 22.

[0021] The stator core 21 is electrically connected to the housing 3. The stator core 21 has an inner peripheral surface 23 that faces the outer peripheral surface 13 of the rotor core 11 in the radial direction. An air gap is provided between the inner peripheral surface 23 of the stator core 21 and the outer peripheral surface 13 of the rotor core 11.

[0022] The stator core 21 is provided with a plurality of slots 24 that accommodate portions of the stator windings 22. The plurality of slots 24 are arranged at intervals in the circumferential direction. Each of the plurality of slots 24 has an opening 24A (see FIG. 2) that opens to the inner circumferential surface 23, for example.

[0023] The stator winding 22 is wound around the stator core 21. The stator winding 22 has a plurality of first portions 22A accommodated in each of the plurality of slots 24 of the stator core 21 and a plurality of second portions 22B protruding outward from the stator core 21 in the direction of extension of the axis CA. Each of the second portions 22B is a portion connecting two of the first portions 22A accommodated in each of two adjacent slots 24 in the circumferential direction, i.e., a coil end. The entire stator winding 22 is disposed outside the inner circumferential surface 23 of the stator core 21. The stator winding 22 is, for example, a normal conducting winding. Note that the stator winding 22 may also be a superconducting winding.

[0024] The housing 3 accommodates the rotor 1 and the stator 2. The housing 3 has a first wall portion 3A and a second wall portion 3B that face each other in the direction in which the axis CA extends, and a third wall portion 3C that connects the first wall portion 3A and the second wall portion 3B. The first shaft 10A has a portion that is disposed outside the first wall portion 3A. The second shaft 10B has a portion that is disposed outside the second wall portion 3B. The stator 2 is fixed to the third wall portion 3C via a magnetic shield 6. The stator core 21 is electrically connected to the third wall portion 3C. The first wall portion 3A and the second wall portion 3B are, for example, at the same potential as the stator core 21.

[0025] The housing 3 has a structure for discharging the cooling medium to the outside, the details of which will be described later.

[0026] The pair of bearings 4 includes a first bearing 4A that rotatably supports the first shaft 10A and a second bearing 4B that rotatably supports the second shaft 10B. The first bearing 4A and the second bearing 4B are, for example, rolling bearings. The first bearing 4A has an inner ring connected to the first shaft 10A, an outer ring connected to the first wall portion 3A of the housing 3, and rolling elements. The second bearing 4B has an inner ring connected to the second shaft 10B, an outer ring connected to the second wall portion 3B of the housing 3, and rolling elements. In the first bearing 4A and the second bearing 4B, lubricating oil is supplied between the inner ring and the outer ring and between the rolling elements and the rolling elements.

[0027] The outer ring of the first bearing 4A is electrically connected to the stator core 21 via the first wall portion 3A and the third wall portion 3C. The inner ring of the first bearing 4A is electrically connected to the first shaft 10A. The outer ring of the second bearing 4B is electrically connected to the stator core 21 via the second wall portion 3B and the third wall portion 3C. The inner ring of the second bearing 4B is electrically connected to the second shaft 10B. In each of the first bearing 4A and the second bearing 4B, the potential difference between the inner ring and the outer ring is equal to the potential difference between the room temperature damper of the rotor 1 and the stator core 21.

[0028] The electrostatic shield 5 has a portion that is disposed between the rotor 1 and the stator 2 in the radial direction. The portion of the electrostatic shield 5 is disposed in the gap between the outer peripheral surface 13 of the temperature damper 16 and the inner peripheral surface 23 of the stator core 21. The electrostatic shield 5 is disposed at a distance from each of the outer peripheral surface 13 of the temperature damper 16 and the inner peripheral surface 23 of the stator core 21 in the radial direction. The electrostatic shield 5 is disposed at a distance from each of the plurality of first portions and the plurality of second portions of the stator winding 22 in the radial direction.

[0029] The electrostatic shield 5 is electrically connected to the housing 3. The electrostatic shield 5 is fixed to the housing 3. The electrostatic shield 5 spans between the first wall 3A and the second wall 3B. The electrostatic shield 5 has one end electrically connected to the first wall 3A and the other end electrically connected to the second wall 3B. The one end of the electrostatic shield 5 is fixed to the first wall 3A. The other end of the electrostatic shield 5 is fixed to the second wall 3B. The electrostatic shield 5 has the same potential as the first wall 3A and the second wall 3B.

[0030] Hereinafter, the internal space of the housing 3, which is located closer to the rotor 1 than the electrostatic shield 5 in the radial direction, will be referred to as a first space S1. The internal space of the housing 3, which is located on the opposite side of the electrostatic shield 5 from the rotor 1 in the radial direction, will be referred to as a second space S2. The electrostatic shield 5 has a plurality of communication holes 50 that communicate between the first space S1 and the second space S2. The communication holes 50 are arranged at intervals from one another in both the direction of extension of the axis CA and the circumferential direction. Each of the communication holes 50 is, for example, a through-hole that penetrates the electrostatic shield 5 in the radial direction. Each of the communication holes 50 is arranged at intervals from the outer circumferential surface 13 of the room temperature damper 16 and the inner circumferential surface 23 of the stator core 21 in the radial direction. The number of communication holes 50 may be any number.

[0031] The material constituting the electrostatic shield 5 includes a non-magnetic material having electrical conductivity. The material constituting the electrostatic shield 5 includes, for example, at least one of Cu and aluminum (Al). The electrostatic shield 5 may have a main body made of resin and a conductive film covering the surface of the main body. In this case, it is sufficient that the conductive film is made of a non-magnetic material having electrical conductivity. There are no particular limitations on the method for forming the conductive film. The conductive film may be a plated film. The electrostatic shield 5 may also be a single member made of a non-magnetic material having electrical conductivity. The electrostatic shield 5 is, for example, an annular member.

[0032] The magnetic shield 6 is disposed radially outward of the stator 2 in the housing 3. The magnetic shield 6 is disposed radially between the stator 2 and the third wall portion 3C of the housing 3. The magnetic shield 6 reduces magnetic flux leaking from the inside of the rotating electric machine 101 to the outside.

[0033] 2 is a partially enlarged cross-sectional view showing the rotor 1, stator 2, and electrostatic shield 5 of the rotating electric machine 101, taken along a cross section perpendicular to the axis CA. Note that the illustration of the interior of the rotor 1 in Fig. 2 is simplified compared to Fig. 1. As shown in Fig. 2, the stator core 21 has a back yoke 25, a plurality of teeth 26, and a plurality of flanges 27.

[0034] The back yoke 25 has a cylindrical shape and is connected to the magnetic shield 6 .

[0035] The plurality of teeth 26 protrude from the back yoke 25 toward the rotor 1. The plurality of teeth 26 are arranged at intervals in the circumferential direction. The plurality of slots 24 are formed between the plurality of teeth 26 in the circumferential direction. The stator winding 22 is wound around each of the plurality of teeth 26.

[0036] The plurality of flanges 27 protrude in the circumferential direction from the radial inner circumferential end of each of the plurality of teeth 26. A pair of flanges 27 protruding from the inner circumferential ends of two teeth 26 adjacent to each other in the circumferential direction are arranged at a distance from each other in the circumferential direction. The opening 24A of each of the plurality of slots 24 is formed between the pair of flanges 27.

[0037] The electrostatic shield 5 is disposed so as to overlap, in the radial direction, with the openings 24A of the plurality of slots 24. Note that the communication holes 50 may also be disposed so as to overlap, in the radial direction, with the openings 24A of the plurality of slots 24.

[0038] Next, with reference to FIG. 1, an example of the structure of the rotor 1 for supplying a cooling medium to the rotor windings 12 will be described.

[0039] The rotor 1 is provided with a first flow path F1 through which the cooling medium flows from the outside of the housing 3 through the rotor winding 12 and into the first space. The first flow path F1 has an inlet I1 through which the cooling medium flows in and a plurality of outlets O1 through which the cooling medium flows out. The inlet I1 is connected to a supply unit 111 (described later) outside the housing 3. Each of the plurality of outlets O1 opens onto the outer circumferential surface 13 of the room temperature damper 16.

[0040] The first flow path F1 includes, for example, a third flow path F3, a plurality of fourth flow paths F4, a plurality of slots 14, and a plurality of fifth flow paths F5. The third flow path F3, the plurality of fourth flow paths F4, the plurality of slots 14, and the plurality of fifth flow paths F5 are connected in series with one another. The third flow path F3 includes an inlet I1. Each of the plurality of fifth flow paths F5 includes an outlet O1.

[0041] The third flow path F3 extends along the axis CA. The third flow path F3 is provided inside the first shaft 10A and the rotor core 11. The third flow path F3 is disposed inside the rotor core 11, more inward than the rotor windings 12.

[0042] Each of the plurality of fourth flow paths F4 extends along the radial direction. Each of the plurality of fourth flow paths F4 is provided inside the rotor core 11, radially inward of the rotor windings 12. Each of the plurality of fourth flow paths F4 is connected to the third flow path F3. Each of the plurality of fourth flow paths F4 communicates between the third flow path F3 and each of the plurality of slots 14. Each of the plurality of fourth flow paths F4 is arranged at intervals from one another in the circumferential direction and in the direction in which the axis CA extends.

[0043] Each of the plurality of fifth flow paths F5 extends along the radial direction. Each of the plurality of fifth flow paths F5 is provided inside the rotor core 11, radially outward of the rotor windings 12. Each of the plurality of fifth flow paths F5 is connected to at least one of the plurality of fourth flow paths F4 via a plurality of slots 14. Each of the plurality of fifth flow paths F5 communicates between a respective one of the plurality of slots 14 and the outer peripheral surface 13 of the room-temperature damper 16. Each of the plurality of fifth flow paths F5 is arranged at intervals from one another in the circumferential direction and in the direction in which the axis CA extends.

[0044] The third flow path F3 may be formed by a pipe inserted through the first shaft 10A and a container capable of storing a cooling medium that is provided inside the rotor core 11. Each of the plurality of fourth flow paths F4 and the plurality of fifth flow paths F5 may be formed by, for example, a pipe provided inside the rotor core 11.

[0045] Minute gaps through which the cooling medium can flow exist between adjacent wire rods in the rotor winding 12. The cooling medium that flows from each of the plurality of fourth flow paths F4 into each of the plurality of slots 14 passes through the gaps that exist between adjacent wire rods in the rotor winding 12 and flows out into each of the plurality of fifth flow paths F5.

[0046] The cooling medium flowing through the first flow path F1 cools the rotor winding 12 and then flows into the first space S1. The cooling medium that has flowed into the first space S1 passes through a plurality of communication holes 50 provided in the electrostatic shield 5 and flows into the second space S2.

[0047] Next, with reference to FIG. 1, an example of the structure of the housing 3 for discharging the cooling medium to the outside of the rotating electrical machine 101 will be described.

[0048] The housing 3 is provided with a second flow path F2 through which the cooling medium flows from the second space S2 to the outside of the housing. The second flow path F2 has an inlet I2 through which the cooling medium flows in and an outlet O2 through which the cooling medium flows out. The inlet I2 opens into the second space S2 of the housing 3. The inlet I2 is, for example, located radially outward of the stator 2 and further outward of the stator 2 in the direction of extension of the axis CA. The inlet I2 may be located at the lowest point of the housing 3 in the direction of gravity. This second flow path F2 allows the cooling medium in a liquefied state to be efficiently collected. The inlet I2 may be located at the highest point of the housing 3 in the direction of gravity. This second flow path F2 allows the cooling medium in a vaporized state to be efficiently collected. The inlet I2 opens, for example, into a space portion located at an upper part of the second space S2. The outlet O2 is connected to a collection unit 121 (described later) outside the housing 3.

[0049] The second flow path F2 is arranged, for example, on the opposite side of the stator 2 from the load in the direction in which the axis CA extends.

[0050] 1 , a rotating electric machine system 201 according to the first embodiment mainly includes a rotating electric machine 101 according to the first embodiment, a supply unit 111, and a recovery unit 121. In the rotating electric machine system 201, the rotating electric machine 101, the supply unit 111, and the recovery unit 121 are included in a circuit through which at least a portion of the cooling medium circulates, for example.

[0051] The supply unit 111 supplies the cooling medium to the rotating electric machine 101. The supply unit 111 is connected to the inlet I1 of the first flow path F1. Preferably, the supply unit 111 supplies the cooling medium in a liquid phase to the rotating electric machine 101. The supply unit 111 has, for example, a pump for feeding the cooling medium.

[0052] The recovery unit 121 recovers the cooling medium from the rotating electrical machine 101. The recovery unit 121 recovers, for example, a gas phase cooling medium from the rotating electrical machine 101. The recovery unit 121 includes, for example, a pump.

[0053] The rotating electrical machine system 201 includes, for example, a cooling unit 131 and a storage unit 141. In the rotating electrical machine system 201, the cooling unit 131 and the storage unit 141 are included in the above-mentioned circuit.

[0054] The cooling unit 131 cools the cooling medium recovered from the rotating electric machine 101 by the recovery unit 121. The cooling unit 131 is, for example, a condensation unit that condenses gas-phase cooling medium into liquid-phase cooling medium. The cooling unit 131 is, for example, a heat exchanger. The storage unit 141 stores the cooling medium. The storage unit 141 stores, for example, the liquid-phase cooling medium condensed by the cooling unit 131.

[0055] The cooling medium is not particularly limited as long as it can appropriately cool the rotor winding 12. When the rotor winding 12 is a low-temperature superconducting winding, the cooling medium is, for example, liquid helium. When the rotor winding 12 is a high-temperature superconducting winding, the cooling medium is, for example, liquid nitrogen. The temperature of the cooling medium supplied to the rotor winding 12 is equal to or lower than the transposition temperature of the superconducting winding. The evaporation temperature of the cooling medium is higher than the transposition temperature of the superconducting winding.

[0056] In the rotating electrical machine system 201, the shaft 10 is connected to a load (not shown) on the side of the second shaft 10B. The turbine is provided to rotate around the axis CA together with the shaft 10. Examples of the load of the rotating electrical machine system 201 include a gear and a power mechanism.

[0057] <Function> The rotating electric machine 101 includes an electrostatic shield 5 that has a portion disposed between the rotor 1 and the stator winding 22 in the radial direction and is electrically connected to the housing 3. Compared to a rotating electric machine that does not include the electrostatic shield 5, the electrostatic shield 5 reduces the stray capacitance between the rotor 1 and the stator winding 22 and reduces the potential difference between the inner ring and outer ring of each of the first bearing 4A and the second bearing 4B. As a result, the risk of damage to each of the first bearing 4A and the second bearing 4B in the rotating electric machine 101 can be reduced compared to the risk of damage to the bearings in conventional rotating electric machines.

[0058] The electrostatic shield 5 of the rotating electric machine 101 is provided with a plurality of communication holes 50 that communicate between the first space S1 and the second space S2. The plurality of communication holes 50 can prevent heat generated in the rotor 1 from accumulating in the first space S1 and prevent heat generated in the stator 2 from accumulating in the second space S2. When the cooling medium is supplied into the housing 3 as described above, the plurality of communication holes 50 can prevent the cooling medium from stagnating in each of the first space S1 and the second space S2. When the cooling medium is supplied to the first space S1 as described above, the cooling medium can flow from the first space S1 through the plurality of communication holes 50 into the second space S2. As a result, according to the rotating electric machine 101, the electrostatic shield 5 can efficiently cool each of the rotor 1 and the stator 2 while reducing the risk of damage to each of the first bearing 4A and the second bearing 4B.

[0059] In the rotating electric machine 101, the rotor 1 has a rotor winding 12, so the amount of magnetic flux in the rotor 1 can be adjusted according to the amount of current flowing through the rotor winding 12. In the rotating electric machine 101, a superconducting winding is used as the rotor winding 12. Therefore, if the temperature of the cooling medium supplied to the rotor winding 12 is set to a superconducting transition temperature or lower, the rotor winding 12 can be efficiently maintained in a superconducting state. The stator 2 can be cooled by the cooling medium used to cool the rotor winding 12. In the rotating electric machine 101, the electrostatic shield 5 reduces the risk of damage to each of the first bearing 4A and the second bearing 4B, while still achieving cooling performance for the rotor 1 that is equal to or greater than the cooling performance required for the rotor of a superconducting rotating electric machine.

[0060] In the rotating electric machine 101, the electrostatic shield 5 is electrically connected to each of the first wall portion 3A and the second wall portion 3B of the housing 3, among the stator core 21 and the housing 3. The electrostatic shield 5 is disposed at a distance from each of the inner circumferential surfaces 23 of the stator core 21 in the radial direction. The plurality of communication holes 50 are not blocked by the inner circumferential surface 23 of the stator core 21. In this rotating electric machine 101, the cooling efficiency for the stator 2 is higher than when the electrostatic shield 5 is connected to the inner circumferential surface 23 of the stator core 21. In the rotating electric machine 101, because the cooling efficiency for the stator 2 is high, the stator winding 22 can also be a superconducting winding.

[0061] In the rotating electric machine 101, the electrostatic shield 5 is placed between the first wall portion 3A and the second wall portion 3B. Because the electrostatic shield 5 is disposed between the rotor 1 and the entire stator winding 22 in the radial direction, the stray capacitance between the rotor 1 and the stator winding 22 can be made smaller than in the rotating electric machine 102 described below, and the potential difference between the inner ring and outer ring of each of the first bearing 4A and the second bearing 4B can be made smaller.

[0062] The rotating electric machine system 201 includes a rotating electric machine 101, a supply unit 111, a recovery unit 121, and a cooling unit 131. Therefore, by configuring a circuit including the rotating electric machine 101, the supply unit 111, the recovery unit 121, and the cooling unit 131, the rotor 1 and the stator 2 of the rotating electric machine 101 can be efficiently cooled by the cooling medium circulating through the circuit. Preferably, the rotating electric machine system 201 further includes a storage unit 141. The rotating electric machine system 201 including the storage unit 141 can appropriately control the flow rate of the cooling medium circulating through the circuit, thereby achieving even higher efficiency of the rotating electric machine system 201.

[0063] <Modifications> The rotor winding 12 may be a normal conducting winding. In this case, the electrostatic shield 5 can reduce the risk of damage to the first bearing 4A and the second bearing 4B, while suppressing the occurrence of problems associated with heat generation in the rotor winding 12 and the stator winding 22. The rotor 1 does not need to have one or both of the low-temperature damper 15 and the room-temperature damper 16. The outer circumferential surface 13 may be the outer circumferential surface of any member that forms the outer shell of the rotor 1 in the radial direction.

[0064] The structure of the rotor 1 for supplying the cooling medium to the rotor windings 12 is not limited to the example structure shown in FIG.

[0065] The number of each of the above-described elements included in the rotating electric machine 101 and the rotating electric machine system 201 may be any number.

[0066] Embodiment 2 Unless otherwise specified, a rotating electric machine according to embodiment 2 has the same configuration, operating principle, and effects as those of embodiment 1. Therefore, the same components as those of embodiment 1 are given the same reference numerals, and descriptions thereof will not be repeated.

[0067] As shown in FIG. 3, a rotating electric machine 102 according to the second embodiment includes a first electrostatic shield 5A and a second electrostatic shield 5B.

[0068] The first electrostatic shield 5A and the second electrostatic shield 5B are spaced apart from each other in the direction of extension of the axis CA. The first electrostatic shield 5A is electrically connected to the first wall 3A. The second electrostatic shield 5B is electrically connected to the second wall 3B.

[0069] For example, one end of the first electrostatic shield 5A in the direction of extension of the axis CA is electrically connected to the first wall portion 3A, and the other end of the first electrostatic shield 5A in the direction of extension of the axis CA is disposed at a distance from the stator core 21 in the direction of extension of the axis CA.

[0070] For example, one end of second electrostatic shield 5B in the direction of extension of axis CA is electrically connected to second wall portion 3B. The other end of second electrostatic shield 5B in the direction of extension of axis CA is disposed at a distance from stator core 21 in the direction of extension of axis CA.

[0071] Each of the first electrostatic shield 5A and the second electrostatic shield 5B is disposed at a distance from the stator core 21 in the direction in which the axis CA extends. Each of the first electrostatic shield 5A and the second electrostatic shield 5B is disposed at a distance from some of the second portions 22B of the stator winding 22 in the radial direction.

[0072] From a different perspective, the electrostatic shield 5 has openings that open to regions that overlap with the stator core 21 in the radial direction. The electrostatic shield 5 is disposed so as to overlap with each of the second portions 22B of the stator winding 22 in the radial direction.

[0073] In the rotating electric machine 102, the electrostatic shield 5 does not overlap with the stator core 21 in the radial direction, so the coolant can easily flow into the multiple slots 24 of the stator core 21. As a result, the rotating electric machine 102 has a higher cooling efficiency for the stator 2 than the rotating electric machine 101.

[0074] The rotating electric machine system 202 according to the second embodiment has the same configuration as the rotating electric machine system 201 except that it includes the rotating electric machine 102 .

[0075] <Modifications> The rotating electric machine 102 can be modified in the same manner as the rotating electric machine 101 .

[0076] Embodiment 3. Unless otherwise specified, the rotating electric machine according to embodiment 3 has the same configuration, operating principle, and effects as those of the above-described embodiment 1 or embodiment 2. Therefore, the same components as those of embodiment 1 or embodiment 2 are denoted by the same reference numerals, and description thereof will not be repeated.

[0077] As shown in FIGS. 4 and 5, a rotating electric machine 103 according to the third embodiment includes a plurality of first electrostatic shields 5A and a plurality of second electrostatic shields 5B.

[0078] Each of the plurality of first electrostatic shields 5A and the plurality of second electrostatic shields 5B is electrically connected to the housing 3 via the stator core 21. Each of the plurality of first electrostatic shields 5A is arranged at intervals from one another in the circumferential direction. Each of the plurality of second electrostatic shields 5B is arranged at intervals from one another in the circumferential direction.

[0079] Each of the plurality of first electrostatic shields 5A and the plurality of second electrostatic shields 5B has a third portion 51 disposed inside each of the plurality of slots 24. The third portion 51 of each of the plurality of first electrostatic shields 5A and the plurality of second electrostatic shields 5B is electrically connected to the stator core 21. The third portion 51 of each of the first electrostatic shields 5A and the second electrostatic shields 5B is provided so as to block a portion of the opening of each of the plurality of slots 24, for example.

[0080] Each of the plurality of first electrostatic shields 5A and the plurality of second electrostatic shields 5B further has a fourth portion 52 that is disposed, for example, in the radial direction between the rotor 1 and the plurality of second portions 22B of the stator winding 22. The fourth portion 52 of each of the plurality of first electrostatic shields 5A and the plurality of second electrostatic shields 5B is disposed at a distance from the housing 3. The fourth portion 52 of each of the plurality of first electrostatic shields 5A and the plurality of second electrostatic shields 5B is disposed at a distance from the stator winding 22.

[0081] 5 , the third portions 51 of each of the plurality of first electrostatic shields 5A and the plurality of second electrostatic shields 5B are disposed in the radial direction between each of the plurality of first portions 22A of the stator winding 22 and the pair of flanges 27. Each third portion 51 is, for example, electrically connected to each of the pair of flanges 27. Each third portion 51 is in contact with, for example, each of the pair of flanges 27 and the tip portions of each of the plurality of teeth 26 connected to each of the pair of flanges 27.

[0082] In the rotating electric machine 103, similarly to the rotating electric machine 102, the electrostatic shield 5 does not overlap with the stator core 21 in the radial direction, so the coolant can easily flow between the first space S1 and the second space S2. As a result, the rotating electric machine 103 has a higher cooling efficiency for the stator 2 than the rotating electric machine 101.

[0083] Furthermore, in the rotating electric machines 101 and 102, the stator 2 and the electrostatic shield 5 must be fixed separately to the housing 3, and therefore it is necessary to manage assembly tolerances, manufacturing tolerances, and the like, for the stator 2, the housing 3, and the electrostatic shield 5. In contrast, in the rotating electric machine 103, the electrostatic shield 5 can be fixed to the housing 3 as a single unit with the stator 2. Therefore, with the rotating electric machine 103, it is possible to ease the management of assembly tolerances, manufacturing tolerances, and the like, between the stator 2 and the electrostatic shield 5 and the housing 3.

[0084] The rotating electric machine system 203 according to the third embodiment has the same configuration as the rotating electric machine system 201 except that it includes the rotating electric machine 103 .

[0085] <Modification> Each of the first electrostatic shield 5A and the second electrostatic shield 5B may be fixed to an end surface of the stator core 21 in the direction in which the axis CA extends.

[0086] The rotating electric machine 103 may include only one of the first electrostatic shield 5A and the second electrostatic shield 5B as the electrostatic shield. For example, if the mechanical stress applied to the second bearing 4B is greater than the mechanical stress applied to the first bearing 4A, the rotating electric machine 103 may include only the second electrostatic shield 5B as the electrostatic shield so that the electrical stress applied to the second bearing 4B is smaller than the electrical stress applied to the first bearing 4A.

[0087] Rotating electric machine 103 can be modified in the same manner as rotating electric machines 101 and 102. Embodiment 4 Unless otherwise specified, a rotating electric machine according to embodiment 4 has the same configuration, operating principle, and effects as any of the above-described embodiments 1 to 3. Therefore, the same components as those in the above-described embodiments 1 to 3 are denoted by the same reference numerals, and description thereof will not be repeated.

[0088] As shown in FIG. 6 , the rotating electric machine 104 according to the fourth embodiment includes a plurality of electrostatic shields 5. Each of the plurality of electrostatic shields 5 is electrically connected to the housing 3 via the stator core 21. Each of the plurality of electrostatic shields 5 is disposed only within each of the plurality of slots 24, for example. Each of the plurality of electrostatic shields 5 is disposed only between the rotor 1 and the plurality of first portions 22A of the stator winding 22 in the radial direction, for example. Each of the plurality of electrostatic shields 5 is not disposed between the rotor 1 and the plurality of second portions 22B of the stator winding 22 in the radial direction, for example. From a different perspective, each of the plurality of electrostatic shields 5 is formed of, for example, only the third portion 51.

[0089] 7 , the third portion 51 of each of the plurality of electrostatic shields 5 is disposed in the radial direction between each of the plurality of first portions 22A of the stator winding 22 and the pair of flanges 27. Each third portion 51 is, for example, electrically connected to each of the pair of flanges 27. Each third portion 51 is in contact with, for example, each of the pair of flanges 27 and the tip portions of each of the plurality of teeth 26 connected to each of the pair of flanges 27.

[0090] In the rotating electric machine 104, the electrostatic shield 5 does not overlap with the second portion 22B of the stator winding 22 in the radial direction, so the coolant can easily flow between the first space S1 and the second space S2. As a result, the rotating electric machine 104 has a higher cooling efficiency for the stator 2 than the rotating electric machine 101.

[0091] In the rotating electric machine 104, similarly to the rotating electric machine 103, the electrostatic shield 5 can be fixed to the housing 3 as one unit with the stator 2. Therefore, with the rotating electric machine 104, it is possible to ease the management of assembly tolerances and manufacturing tolerances between the stator 2 and the electrostatic shield 5 and the housing 3.

[0092] The rotating electric machine system 204 according to the fourth embodiment has the same configuration as the rotating electric machine system 201 except that it includes the rotating electric machine 104 .

[0093] <Modifications> The rotating electric machine 104 can be modified in the same manner as the rotating electric machines 101 to 103.

[0094] The embodiments disclosed herein should be considered to be illustrative in all respects and not restrictive. Unless inconsistent, at least two of the embodiments disclosed herein may be combined. For example, a rotating electric machine 105 shown in FIG. 8 has a structure combining the rotating electric machine 101 and the rotating electric machine 104. As shown in FIG. 8, the plurality of electrostatic shields 5 may have third portions 51 that are stretched between the first wall portion 3A and the second wall portion 3B and are disposed inside each of the plurality of slots 24.

[0095] The rotating electric machine system 205 according to the fifth embodiment has the same configuration as the rotating electric machine system 201 except that it includes the rotating electric machine 105 .

[0096] The scope of the present disclosure is defined by the claims, rather than the above description, and is intended to include all modifications within the meaning and scope of the claims.

[0097] 1 rotor, 10 shaft, 10A first shaft, 10B second shaft, 11 rotor core, 12 rotor winding, 13 outer peripheral surface, 14 slot, 15 low-temperature damper, 16 room-temperature damper, 2 stator, 21 stator core, 22 stator winding, 22A first portion, 22B second portion, 23 inner peripheral surface, 24 slot, 24A opening, 25 back yoke, 26 teeth, 27 flange, 3 housing, 3A first wall portion, 3B second wall portion, 3C third wall portion, 4 bearing, 4A first bearing, 4B second bearing, 5 electrostatic shield, 5A first electrostatic shield, 5B second electrostatic shield, 50 communication hole, 51 third portion, 6 magnetic shield, 101, 102, 103, 104, 105 rotating electric machine, 111 Supply section, 121 recovery section, 131 cooling section, 141 storage section, 201, 202, 203, 204 rotating electrical machine system, CA axis, F1 first flow path, F2 second flow path, F3 third flow path, F4 fourth flow path, F5 fifth flow path, I1, I2 inlet, O1, O2 outlet, S1 first space, S2 second space.

Claims

1. A rotating electric machine comprising: a rotor rotatable around an axis; a stator; a housing that accommodates the rotor and the stator; and a plurality of bearings that rotatably support the rotor relative to the housing, wherein the rotor has a shaft, a rotor core connected to the shaft, and a rotor winding wound around the rotor core, and the stator has a stator core connected to the housing and a stator winding, and further comprising at least one electrostatic shield having a portion that is disposed between the rotor and the stator in a radial direction relative to the axis, wherein the at least one electrostatic shield has a plurality of communication holes that communicate between a first space located on the rotor side of the at least one electrostatic shield in the radial direction, and a second space located on the opposite side of the rotor from the at least one electrostatic shield in the radial direction, wherein each of the plurality of bearings has an inner ring electrically connected to the shaft and an outer ring electrically connected to the housing, and the at least one electrostatic shield is electrically connected to either the stator core or the housing.

2. The rotating electric machine described in claim 1, wherein the shaft comprises a first shaft extending on one side of the rotor core in the extension direction of the axis, and a second shaft extending on the other side of the rotor core in the extension direction; the plurality of bearings comprise a first bearing that rotatably supports the first shaft, and a second bearing that rotatably supports the second shaft; the housing comprises a first wall portion connected to the outer ring of the first bearing, and a second wall portion connected to the outer ring of the second bearing; and the at least one electrostatic shield is electrically connected to at least one of the first wall portion and the second wall portion.

3. The rotating electric machine according to claim 2, wherein said at least one electrostatic shield is disposed between said first wall portion and said second wall portion.

4. The rotating electric machine according to claim 2, wherein the at least one electrostatic shield is a plurality of electrostatic shields having a first electrostatic shield and a second electrostatic shield, the first electrostatic shield and the second electrostatic shield are arranged at intervals from each other in the direction of extension of the axis, the first electrostatic shield is electrically connected to the first wall portion, and the second electrostatic shield is electrically connected to the second wall portion.

5. A rotating electric machine according to any one of claims 2 to 4, wherein said at least one electrostatic shield is disposed at a distance from said stator.

6. The rotating electric machine according to claim 1, wherein said at least one electrostatic shield is electrically connected to said housing through said stator core.

7. A rotating electric machine as set forth in claim 6, wherein the shaft comprises a first shaft extending on one side of the rotor winding in the direction of extension of the axis, and a second shaft extending on the other side of the rotor winding in the direction of extension, the plurality of bearings comprise a first bearing that rotatably supports the first shaft, and a second bearing that rotatably supports the second shaft, the housing has a first wall portion connected to the outer ring of the first bearing, and a second wall portion connected to the outer ring of the second bearing, the at least one electrostatic shield comprises a plurality of electrostatic shields having a first electrostatic shield and a second electrostatic shield, the first electrostatic shield and the second electrostatic shield are arranged at intervals from each other in the direction of extension of the axis, the first electrostatic shield is electrically connected to one end of the stator core in the direction of extension of the axis, and the second electrostatic shield is electrically connected to the other end of the stator core in the direction of extension of the axis.

8. A rotating electric machine according to any one of claims 1 to 7, wherein the stator core has an inner peripheral surface surrounding the rotor winding in the radial direction, the stator core is provided with at least one slot opening onto the inner peripheral surface, a portion of the stator winding is arranged in the at least one slot, and the at least one electrostatic shield has a portion arranged in the at least one slot so as to block the opening of the at least one slot.

9. The rotating electric machine according to claim 8, wherein said at least one electrostatic shield consists only of a portion disposed within said at least one slot.

10. A rotating electric machine as described in claim 8 or 9, wherein the stator core has a cylindrical back yoke, a plurality of teeth protruding from the back yoke toward the rotor, and a plurality of flanges protruding circumferentially relative to the shaft from the radial inner circumferential end of each of the plurality of teeth, the at least one slot is formed between the plurality of teeth, the opening of the at least one slot is formed between the flanges of each of the plurality of teeth, and the at least one electrostatic shield is positioned radially between the portion of the stator winding and the flange.

11. A rotating electric machine according to any one of claims 6 to 10, wherein the at least one electrostatic shield is disposed at a distance from the housing.

12. A rotating electric machine according to any one of claims 1 to 11, wherein the housing is a container for containing a cooling medium for cooling the rotor winding, the rotor is provided with a first flow path for the cooling medium to flow from the outside of the housing through the rotor winding into the first space, and the housing is provided with a second flow path for the cooling medium to flow from the second space to the outside of the housing.

13. The rotating electric machine according to claim 12, wherein the rotor winding is a superconducting winding.

14. A rotating electric machine system comprising: a rotating electric machine according to claim 12 or 13; a supply unit for supplying the cooling medium to the first flow path; and a recovery unit for recovering the cooling medium from the second flow path.

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