Rotary electrical machine

Abstract

One aspect of a rotary electrical machine according to the present invention comprises a rotor that can rotate about the center axis, a stator that faces the rotor with a gap therebetween, and a fluid supply unit that supplies a fluid to the rotor. The rotor has a rotor core that is provided with a plurality of slots which are arranged in the circumferential direction and which pass through the rotor core in the axial direction, a plurality of conductor parts that are respectively disposed in the plurality of slots, and a pair of end rings that are respectively located on one side of the rotor core in the axial direction and the other side of the rotor core in the axial direction and that connect the plurality of conductor parts. The rotor can rotate at a rotational speed of not less than 20,000 rpm. The fluid supply unit has an injection hole that is open toward a surface of each end ring in the axial direction. The direction in which the injection hole is open is inclined radially inward with respect to the axial direction at a prescribed injection angle. The injection angle is not less than 10° but not more than 50°.

Description

Rotating electric machines

[0001] The present invention relates to a rotating electric machine.

[0002] There is known a rotating electric machine such as an induction machine having a structure in which a refrigerant liquid is supplied to end rings provided on a rotor (for example, Japanese Patent Publication No. 2023-135990).

[0003] Japanese Patent Publication No. 2023-135990

[0004] In the rotating electric machine described above, the rotor is cooled by supplying a fluid such as a refrigerant liquid to the end rings of the rotor. However, for example, as the rotation speed of the rotor increases, the fluid may be repelled by the rotating end rings, making it difficult to supply the fluid to the end rings. This may result in a decrease in the cooling efficiency of the rotor.

[0005] In view of the above circumstances, one object of the present invention is to provide a rotating electrical machine having a structure that can improve the cooling efficiency of the rotor.

[0006] One aspect of the rotating electric machine of the present invention includes a rotor rotatable about a central axis, a stator facing the rotor with a gap therebetween, and a fluid supply unit that supplies fluid to the rotor. The rotor includes a rotor core having a plurality of slots arranged circumferentially and penetrating in the axial direction, a plurality of conductors disposed in the plurality of slots, and a pair of end rings located on one axial side of the rotor core and the other axial side of the rotor core, respectively, and connecting the plurality of conductors. The rotor is rotatable at a rotation speed of 20,000 rpm or more. The fluid supply unit has injection holes that open toward the axial surfaces of the end rings. The opening direction of the injection holes is inclined radially inward with respect to the axial direction at a predetermined injection angle. The injection angle is 10° or more and 50° or less.

[0007] According to one aspect of the present invention, the cooling efficiency of the rotor in a rotating electrical machine can be improved.

[0008] FIG. 1 is a cross-sectional view of a rotating electric machine according to an embodiment. FIG. 2 is a cross-sectional view of a rotor according to an embodiment, taken along line II-II in FIG. 1 . FIG. 3 is a cross-sectional view of a portion of a rotating electric machine according to an embodiment. FIG. 4 is a view of an end ring and a fluid supply unit according to an embodiment, viewed from one axial side. FIG. 5 is a diagram illustrating conditions for first to fifth simulations according to examples. FIG. 6 is a graph illustrating results of first to fourth simulations according to examples. FIG. 7 is a diagram illustrating a portion of the results of the first simulation according to examples. FIG. 8 is a diagram illustrating another portion of the results of the first simulation according to examples. FIG. 9 is a graph illustrating results of the first and fifth simulations according to examples. FIG. 10 is a diagram illustrating conditions for a sixth simulation according to examples. FIG. 11 is a graph illustrating results of the first and sixth simulations according to examples.

[0009] In the drawings, an XYZ coordinate system is shown as a three-dimensional Cartesian coordinate system as appropriate. In the XYZ coordinate system, the Z-axis direction is the up-down direction. The up-down direction is, for example, the vertical direction. The side toward which the Z-axis arrow points (+Z side) is the upper side, and the opposite side to the side toward which the Z-axis arrow points (-Z side) is the lower side. The X-axis direction is a direction perpendicular to the Z-axis direction. The X-axis direction is, for example, the front-to-rear direction of a vehicle in which the rotating electric machine 100 of this embodiment is mounted. The Y-axis direction is a direction perpendicular to both the Z-axis direction and the X-axis direction. The Y-axis direction is, for example, the left-to-right direction of a vehicle in which the rotating electric machine 100 of this embodiment is mounted, i.e., the vehicle width direction.

[0010] The central axis J shown in the drawings as appropriate is a virtual axis representing the central axis of the rotating electric machine 100 of this embodiment. In this embodiment, the central axis J extends in a direction intersecting the up-down direction. More specifically, the central axis J extends in the Y-axis direction, which is perpendicular to the up-down direction. In the following description, unless otherwise specified, the direction parallel to the central axis J, i.e., the Y-axis direction, will be simply referred to as the "axial direction," the radial direction about the central axis J will be simply referred to as the "radial direction," and the circumferential direction about the central axis J will be simply referred to as the "circumferential direction." In the following description, the side of the axial direction toward which the Y-axis arrow points (+Y side) will be referred to as the "one axial side," and the side of the axial direction opposite to the side toward which the Y-axis arrow points (-Y side) will be referred to as the "other axial side."

[0011] The rotating electric machine 100 of this embodiment shown in FIG. 1 is an induction motor. More specifically, the rotating electric machine 100 is a squirrel-cage three-phase induction motor. In this embodiment, the rotating electric machine 100 is a motor mounted on a vehicle. The vehicle on which the rotating electric machine 100 is mounted is a vehicle powered by a motor, such as a hybrid electric vehicle (HEV), a plug-in hybrid vehicle (PHV), or an electric vehicle (EV). The rotating electric machine 100 of this embodiment is used as a power source for the vehicle on which it is mounted.

[0012] As shown in FIG. 1 , the rotating electric machine 100 includes a rotor 10, a stator 20, and a housing 70. In this embodiment, the rotor 10 is a squirrel-cage rotor. The stator 20 generates a rotating magnetic flux by an alternating current. The rotating magnetic flux generated from the stator 20 generates an induced current in a conductor portion 40 (described later) of the rotor 10. A rotational force is generated in the rotor 10 by the rotating magnetic flux generated from the stator 20 and the induced current generated in the rotor 10.

[0013] The housing 70 includes a housing main body 71 and a lid 72. The housing main body 71 is cylindrical and opens to one axial side (+Y side). The housing main body 71 includes a bottom 73 and a cylindrical portion 74. The bottom 73 is located on the other axial side (-Y side) of the stator 20. The bottom 73 includes a bearing holder 73a that holds the bearing 17. The cylindrical portion 74 extends from the radial outer edge of the bottom 73 to one axial side. The cylindrical portion 74 is, for example, cylindrical and centered on the central axis J. The lid 72 is fixed to the end of the housing main body 71 on one axial side. The lid 72 is located on one axial side of the stator 20. The lid 72 includes a bearing holder 72a that holds the bearing 16.

[0014] The stator 20 is fixed to the inner circumferential surface of the cylindrical portion 74. The stator 20 is, for example, substantially annular in shape, centered on the central axis J. The stator 20 faces the rotor 10 with a gap therebetween. The stator 20 is located radially outward of the rotor 10. The stator 20 surrounds the rotor 10. The stator 20 has a stator core 21 and a plurality of coils 22. The stator core 21 has a core back 23 and a plurality of teeth 24. The core back 23 is annular and surrounds the rotor 10. The plurality of teeth 24 extend radially inward from the inner circumferential surface of the core back 23. The plurality of teeth 24 are arranged at intervals in the circumferential direction. The plurality of coils 22 are attached to the plurality of teeth 24, respectively.

[0015] The rotor 10 is rotatable about the central axis J. The rotor 10 is rotatable at a rotation speed of 20,000 rpm (revolutions per minute) or more. In this embodiment, the rotor 10 is rotatable at a rotation speed of 30,000 rpm or more. The rotor 10 is rotatably supported by a pair of bearings 16, 17. The rotor 10 has a rotor core 11, a shaft 13, a plurality of conductor portions 40, a pair of end rings 50a, 50b, and a plate member 60. The shaft 13 is cylindrical and extends axially about the central axis J. The shaft 13 is rotatably supported by the pair of bearings 16, 17.

[0016] The rotor core 11 is fixed to the outer peripheral surface of the shaft 13. The rotor core 11 is cylindrical and surrounds the shaft 13. As shown in FIG. 2 , the rotor core 11 is generally circular when viewed in the axial direction. The outer peripheral surface of the rotor core 11 is located radially inward of the plurality of teeth 24. The outer peripheral surface of the rotor core 11 faces the radially inner surfaces of the plurality of teeth 24 via a gap. The rotor core 11 is formed, for example, by stacking a plurality of electromagnetic steel plates in the axial direction.

[0017] The rotor core 11 is provided with a central hole 11h that penetrates the rotor core 11 in the axial direction. When viewed in the axial direction, the central hole 11h has a substantially circular shape centered on the central axis J. The shaft 13 is inserted into the central hole 11h. The inner circumferential surface of the central hole 11h is provided with a pair of protrusions 15 that protrude radially inward. The outer circumferential surface of the shaft 13 is provided with a pair of grooves 14 into which the pair of protrusions 15 are respectively fitted. By fitting the pair of protrusions 15 into the pair of grooves 14, the rotor core 11 is positioned circumferentially with respect to the shaft 13.

[0018] A plurality of slots 30 are provided in the rotor core 11. The plurality of slots 30 are aligned in the circumferential direction. The plurality of slots 30 are arranged at equal intervals around the circumference in the circumferential direction. The plurality of slots 30 penetrate the rotor core 11 in the axial direction. In this embodiment, the plurality of slots 30 extend in the radial direction when viewed in the axial direction. The radially outer ends of the plurality of slots 30 open to the outer peripheral surface of the rotor core 11.

[0019] The plurality of conductor portions 40 are respectively arranged in the plurality of slots 30. The plurality of conductor portions 40 are made of a non-magnetic, conductive material such as an aluminum alloy. In a cross section perpendicular to the axial direction, the cross-sectional shape of each conductor portion 40 is the same as the cross-sectional shape of each slot 30. As shown in FIG. 1 , the plurality of conductor portions 40 extend in the axial direction from one axial end of the rotor core 11 to the other axial end.

[0020] The pair of end rings 50a, 50b are located on one axial side (+Y side) of the rotor core 11 and the other axial side (-Y side) of the rotor core 11, respectively. The end ring 50a is located on one axial side of the rotor core 11. The end ring 50b is located on the other axial side of the rotor core 11. The pair of end rings 50a, 50b are annular and surround the central axis J. More specifically, the pair of end rings 50a, 50b are substantially annular and centered on the central axis J. The pair of end rings 50a, 50b surround the shaft 13. The inner circumferential surfaces of the pair of end rings 50a, 50b are provided radially outwardly of the outer circumferential surface of the shaft 13 and spaced apart from each other. The end ring 50a is located radially inward of a portion of the coil 22 that protrudes axially beyond the stator core 21. The end ring 50b is located radially inward of a portion of the coil 22 that protrudes axially beyond the stator core 21.

[0021] The end ring 50a is connected to the ends of the multiple conductor portions 40 on one axial side (+Y side). The end ring 50b is connected to the ends of the multiple conductor portions 40 on the other axial side (-Y side). As a result, the pair of end rings 50a, 50b connect the multiple conductor portions 40 together. The multiple conductor portions 40 are short-circuited to each other via the pair of end rings 50a, 50b. An induced current caused by the rotating magnetic flux generated in the stator 20 flows through the multiple conductor portions 40. The induced current flows axially through each conductor portion 40.

[0022] Like the plurality of conductors 40, the pair of end rings 50a, 50b are made of a non-magnetic, conductive material such as an aluminum alloy. In this embodiment, the pair of end rings 50a, 50b and the plurality of conductors 40 are part of the same single member. The pair of end rings 50a, 50b and the plurality of conductors 40 are formed, for example, by die casting. In the following description, when there is no need to distinguish between the end rings 50a and 50b, they may be collectively referred to as end rings 50.

[0023] The plate member 60 is located axially between the end ring 50 and the rotor core 11. The plate member 60 is plate-shaped with its plate surface facing the axial direction. The plate member 60 is annular and surrounds the shaft 13. In this embodiment, a pair of plate members 60 are provided, sandwiching the rotor core 11 in the axial direction. One plate member 60 is located axially between the end ring 50a and the rotor core 11. The other plate member 60 is located axially between the end ring 50b and the rotor core 11.

[0024] The rotating electric machine 100 includes a fluid supply unit 77 that supplies a fluid F to the rotor 10. In this embodiment, the fluid F is oil. For example, an automatic transmission fluid (ATF) can be used as the fluid F. The fluid F supplied from the fluid supply unit 77 to the rotor 10 is not particularly limited and may be a fluid other than oil. The supply of the fluid F to the rotor 10 cools the rotor 10. For example, if the fluid F is oil, at least a portion of the fluid F supplied from the fluid supply unit 77 to the rotor 10 may be supplied to the bearings 16 and 17 as lubricating oil. The viscosity of the fluid F is, for example, 0.01 Pa·s or more and 0.10 Pa·s or less when the temperature of the fluid F is 20°C.

[0025] In this embodiment, the fluid supply unit 77 is provided in the housing 70. In this embodiment, the fluid supply unit 77 includes a fluid supply unit 77a provided in the cover 72 and a fluid supply unit 77b provided in the bottom 73. The fluid supply unit 77a protrudes axially downward from a portion of the surface on the other axial side (-Y side) of the cover 72 that is above the bearing holder 72a. The fluid supply unit 77b protrudes axially downward from a portion of the surface on one axial side (+Y side) of the bottom 73 that is above the bearing holder 73a. In this embodiment, the fluid supply units 77a and 77b are located above the central axis J. The fluid supply unit 77a is located axially toward one side of the end ring 50a. The fluid supply unit 77b is located axially toward the other side of the end ring 50b.

[0026] In the following description, with respect to a certain object, the side closer to the center of the rotor core 11 in the axial direction may be referred to as the "axial inner side," and the side farther from the center of the rotor core 11 in the axial direction may be referred to as the "axial outer side." With regard to the positional relationship between the fluid supply unit 77a and the end ring 50a, the side in the axial direction where the end ring 50a is located relative to the fluid supply unit 77a, i.e., the other axial side (-Y side), is the "axial inner side." With regard to the positional relationship between the fluid supply unit 77b and the end ring 50b, the side in the axial direction where the end ring 50b is located relative to the fluid supply unit 77b, i.e., the one axial side (+ ... other axial side (-Y side), is the "axial outer side." The pair of fluid supply portions 77 a, 77 b are disposed axially outward of the pair of end rings 50 a, 50 b, respectively, and protrude axially inward from the cover 72 or the bottom 73 toward the pair of end rings 50 a, 50 b.

[0027] The fluid supply unit 77a supplies fluid F to the end ring 50a. The fluid supply unit 77b supplies fluid F to the end ring 50b. The fluid supply units 77a and 77b are arranged symmetrically with respect to each other in the axial direction. The fluid supply unit 77b has the same configuration as the fluid supply unit 77a, except that it supplies fluid F to the end ring 50b and is arranged opposite to the fluid supply unit 77a in the axial direction. Therefore, in the following description, the fluid supply unit 77a will be described as a representative of the pair of fluid supply units 77a, 77b, and a description of the fluid supply unit 77b may be omitted.

[0028] As shown in FIG. 3 , the fluid supply portion 77a is cylindrical and opens axially inward (−Y side) and downward. The fluid supply portion 77a is, for example, cylindrical. The fluid supply portion 77a has an injection hole 75. The injection hole 75 is an opening provided at the axially inward and lower end of the fluid supply portion 77a. The injection hole 75 opens into the internal space of the housing 70. The injection hole 75 is, for example, circular when viewed in the direction in which the injection hole 75 opens. The injection hole 75 is an opening provided in a flow path portion 76 through which the fluid F flows. The flow path portion 76 is, for example, provided in a wall portion constituting the housing 70. The flow path portion 76 is connected to, for example, a reservoir (not shown) in which the fluid F is stored. The fluid F flows through the flow path portion 76, and is delivered from the reservoir (not shown) by an electric pump (not shown). A cooler for cooling the fluid F may be provided midway through the flow path portion 76.

[0029] The flow path portion 76 has an ejection flow path portion 76a provided in the fluid supply portion 77a. The internal space of the ejection flow path portion 76a is defined by the internal space of the fluid supply portion 77a. The ejection flow path portion 76a extends linearly in a direction inclined radially with respect to the axial direction. The ejection flow path portion 76a is positioned radially inward as it moves axially inward (toward the -Y side). In this embodiment, the ejection flow path portion 76a extends linearly in a direction inclined vertically with respect to the axial direction. The ejection flow path portion 76a is positioned lower as it moves axially inward. As shown in FIG. 4 , the extension direction of the ejection flow path portion 76a is not inclined circumferentially. In other words, the extension direction of the ejection flow path portion 76a is not inclined in the front-rear direction (X-axis direction). The extension direction of the ejection flow path portion 76a is a direction parallel to the axial direction when viewed in the radial direction in which the ejection flow path portion 76a is inclined with respect to the axial direction. In this embodiment, the direction in which the injection passage portion 76 a extends is parallel to the axial direction when viewed in the vertical direction. The injection passage portion 76 a has an injection hole 75 at its lower end on the inner side in the axial direction, which opens into the interior of the housing 70.

[0030] The injection holes 75 are located above the central axis J. As shown in FIG. 3 , in this embodiment, a portion of the injection holes 75 is located radially outward from the radial outer edge of the end ring 50. In this embodiment, a portion of the injection holes 75 is located above the upper end of the end ring 50. Note that the entire injection holes 75 may be located radially outward from the radially outer end of the end ring 50, or the entire injection holes 75 may be located radially inward from the radially outer end of the end ring 50. The entire injection holes 75 may be located above the upper end of the end ring 50, or the entire injection holes 75 may be located above the upper end of the end ring 50. The radially outer end of the injection holes 75 may be located at the same radial position as the radially outer end of the end ring 50. The upper end of the injection holes 75 may be located at the same vertical position as the upper end of the end ring 50.

[0031] The injection holes 75 open toward the axial surface of the end ring 50. The injection holes 75 of the fluid supply unit 77a open toward the axially outer (+Y side) surface of the end ring 50a. The injection holes 75 of the fluid supply unit 77b open toward the axially outer (-Y side) surface of the end ring 50b.

[0032] The phrase "the injection hole 75 opens toward the axial surface of the end ring 50" means that when the injection hole 75 is projected in the direction in which the injection hole 75 opens, at least a portion of the projected portion is projected onto the axial surface of the end ring 50. The direction in which the injection hole 75 opens is parallel to the direction in which the injection flow path 76a, or the portion of the flow path 76 through which the fluid F injected from the injection hole 75 flows, connects to the injection hole 75. The fluid F injected from the injection hole 75 is injected along the direction in which the injection hole 75 opens and is sprayed onto the axially outer surface of the end ring 50. Note that some of the fluid F injected from the injection hole 75 may scatter and not be sprayed onto the end ring 50. The surface tension generated between the axially outer surface of the end ring 50 and the fluid F is 0.01 N / m or more and 0.1 N / m or less, for example, when the viscosity of the fluid F is 0.01 Pa s or more and 0.10 Pa s or less.

[0033] The direction in which the injection holes 75 open is inclined radially inward with respect to the axial direction at a predetermined injection angle φ. In this embodiment, the injection angle φ is the angle at which the direction in which the injection holes 75 open is inclined downward with respect to the axial direction. The injection angle φ is 10° or more and 50° or less. By setting the injection angle φ to 10° or more and 50° or less, the area of ​​the contact area FA with which the fluid F injected from the injection holes 75 comes into contact can be increased on the axial surface of the end ring 50, even when the rotor 10 rotates at a rotation speed of 20,000 rpm or more. Although the detailed principle behind this is unknown, it is thought to be based on the following principle.

[0034] When the injection angle φ is greater than or equal to 0° and less than 10°, the fluid F is sprayed onto the axial surfaces of the end rings 50 at an angle perpendicular or close to perpendicular to the surfaces. In this case, the momentum of the fluid F sprayed onto the axial surfaces of the end rings 50 has no or a small radially inward component, so the fluid F that comes into contact with the axial surfaces of the end rings 50 is likely to flow radially outward due to centrifugal force. Therefore, the fluid F that comes into contact with the axial surfaces of the end rings 50 is likely to flow radially outward on the surface and splash radially outward from the end rings 50. In particular, when the rotation speed of the rotor 10 is 20,000 rpm or higher, the centrifugal force applied to the fluid F becomes larger, making the fluid F more likely to splash radially outward. On the other hand, when the injection angle φ is 10° or greater, the radially inward component of the momentum of the fluid F sprayed onto the axial surfaces of the end rings 50 becomes larger. Therefore, even if the rotation speed of the rotor 10 is 20,000 rpm or more, and the fluid F in contact with the axial surface of the end ring 50 is subjected to a centrifugal force in the radially outward direction, the fluid F is less likely to flow radially outward. Therefore, on the axial surface of the end ring 50, the fluid F is more likely to spread in the circumferential direction before flowing to the radially outer edge of the end ring 50.

[0035] Furthermore, when the injection angle φ is greater than 50°, the axial component included in the direction of momentum of the fluid F contacting the axial surfaces of the end rings 50 becomes smaller. Therefore, the force with which the fluid F adheres to the axial surfaces of the end rings 50 becomes weaker, and the fluid F becomes more likely to be repelled by the rotating end rings 50. Particularly when the rotation speed of the rotor 10 is 20,000 rpm or higher, the fluid F becomes more likely to be repelled by the end rings 50 rotating at high speed. On the other hand, when the injection angle φ is 50° or less, the axial component included in the direction of momentum of the fluid F sprayed onto the axial surfaces of the end rings 50 can be prevented from becoming smaller. Therefore, even when the rotation speed of the rotor 10 is 20,000 rpm or higher, the fluid F sprayed onto the axial surfaces of the end rings 50 can be more likely to adhere to the axial surfaces of the end rings 50, and the fluid F can be less likely to be repelled by the rotating end rings 50.

[0036] From the above, it is believed that by setting the injection angle φ to be greater than or equal to 10° and less than or equal to 50°, the fluid F sprayed onto the axial surface of the end ring 50 can be more easily spread on the axial surface of the end ring 50, and the area of ​​the contact area FA can be increased, even when the rotation speed of the rotor 10 is 20,000 rpm or more. This is a new finding obtained by the inventors of the present application through simulations. Since the area of ​​the contact area FA where the fluid F contacts the axial surface of the end ring 50 can be increased, the end ring 50 can be more easily cooled by the fluid F. Therefore, the rotor 10 can be more easily cooled by the fluid F, and the cooling efficiency of the rotor 10 can be improved. Furthermore, since the rotor 10 can be more easily cooled by the fluid F, the stator 20, which faces the rotor 10 via a gap, can also be more easily cooled indirectly. Therefore, the cooling efficiency of the stator 20 can also be improved.

[0037] As shown in FIG. 4 , the fluid F injected from the injection holes 75 flows from a contact point IP on the axial surface of the end ring 50 where the fluid F first comes into contact, toward the front in the rotational direction of the rotor 10, while flowing radially outward and spreading on the axial surface of the end ring 50. Therefore, a contact area FA on the axial surface of the end ring 50 where the fluid F injected from the injection holes 75 comes into contact extends from the contact point IP toward the front in the rotational direction of the rotor 10. The arrow θ in FIG. 4 indicates the rotational direction of the rotor 10. The side toward which the arrow θ points (+θ side) is the side toward which the rotating rotor 10 advances in the circumferential direction, i.e., the front side in the rotational direction. The side opposite to the side toward which the arrow θ points (−θ side) is the side opposite to the side toward which the rotating rotor 10 advances in the circumferential direction, i.e., the rear side in the rotational direction.

[0038] In this embodiment, the rotor 10 can rotate at a rotation speed of 30,000 rpm or more. When the rotor 10 rotates at a rotation speed of 30,000 rpm or more, the fluid F sprayed onto the end rings 50 receives a larger radially outward centrifugal force, and the fluid F is more likely to be repelled by the axial surfaces of the end rings 50 rotating at high speed. However, as described above, by setting the injection angle φ to be 10° or more and 50° or less, the contact area FA over which the fluid F spreads on the axial surfaces of the end rings 50 can be easily increased, thereby improving the cooling efficiency of the rotor 10. In other words, the effect obtained by setting the injection angle φ to be 10° or more and 50° or less is more effectively obtained when the rotor 10 rotates at a rotation speed of 30,000 rpm or more.

[0039] In this embodiment, the injection angle φ is 45° or less. In this case, the axial component of the momentum of the fluid F sprayed onto the axial surfaces of the end rings 50 can be prevented from becoming smaller. This makes it easier for the fluid F to adhere to the axial surfaces of the end rings 50, thereby preventing the fluid F from being repelled by the end rings 50. This makes it easier to increase the area of ​​the contact area FA. As described above, when the rotation speed of the rotor 10 reaches 30,000 rpm or more, the fluid F is particularly likely to be repelled by the axial surfaces of the end rings 50, which are rotating at high speed. However, by setting the injection angle φ to 45° or less, the fluid F can be prevented from being repelled by the axial surfaces of the end rings 50, even when the rotation speed of the rotor 10 is 30,000 rpm or more. Therefore, by setting the injection angle φ to 45° or less, the cooling efficiency of the rotor 10 can be improved, even when the rotation speed of the rotor 10 is 30,000 rpm or more.

[0040] In this embodiment, the injection angle φ is 15° or greater. In this case, the radially inward component of the momentum of the fluid F sprayed onto the axial surfaces of the end rings 50 can be increased. This makes it difficult for the fluid F to flow radially outward on the axial surfaces of the end rings 50, making it easier to increase the area of ​​the contact area FA. Here, as described above, when the rotation speed of the rotor 10 reaches 30,000 rpm or greater, the radially outward centrifugal force that the fluid F receives on the axial surfaces of the end rings 50 becomes particularly large. However, by setting the injection angle φ to 15° or greater, it is possible to effectively prevent the fluid F from flowing radially outward on the axial surfaces of the end rings 50, even when the rotation speed of the rotor 10 is 30,000 rpm or greater. Therefore, by setting the injection angle φ to 15° or greater, it is possible to effectively improve the cooling efficiency of the rotor 10, even when the rotation speed of the rotor 10 is 30,000 rpm or greater.

[0041] In this embodiment, the flow velocity of the fluid F injected from the injection holes 75 is 4.0 m / s or less. When the flow velocity of the fluid F injected from the injection holes 75 is faster than 4.0 m / s, the amount of fluid F sprayed onto the end ring 50 per unit time is large. Therefore, even if a portion of the fluid F sprayed onto the end ring 50 is scattered radially outward due to centrifugal force or repelled by the axial surface of the end ring 50, the amount of fluid F remaining on the axial surface of the end ring 50 can be increased to a certain extent. Therefore, when the flow velocity of the fluid F is faster than 4.0 m / s, the area of ​​the contact area FA is easily increased regardless of the injection angle φ, and the range of change in the area of ​​the contact area FA with respect to changes in the injection angle φ is easily small. On the other hand, when the flow velocity of the fluid F injected from the injection holes 75 is 4.0 m / s or less, the amount of fluid F sprayed onto the end ring 50 per unit time is unlikely to be large. Therefore, the range of change in the area of ​​the contact area FA with respect to changes in the injection angle φ is easily large. Therefore, when the flow velocity of the fluid F is 4.0 m / s or less, the area of ​​the contact area FA tends to be small when the injection angle φ is less than 10° or when the injection angle φ is greater than 50°. In other words, when the flow velocity of the fluid F injected from the injection hole 75 is 4.0 m / s or less, it may be difficult to increase the area of ​​the contact area FA, particularly depending on the injection angle φ, which may result in insufficient cooling efficiency for the rotor 10. In contrast, if the injection angle φ is 10° or more and 50° or less, the area of ​​the contact area FA can be easily increased, even when the flow velocity of the fluid F injected from the injection hole 75 is 4.0 m / s or less, thereby improving the cooling efficiency of the rotor 10. Therefore, the effect obtained by setting the injection angle φ to 10° or more and 50° or less is more effectively obtained when the flow velocity of the fluid F injected from the injection hole 75 is 4.0 m / s or less. This reduces the discharge pressure required for the pump supplying the fluid F to the injection hole 75.

[0042] In this embodiment, the flow velocity of the fluid F injected from the injection hole 75 is 3.5 m / s or less. More specifically, the flow velocity of the fluid F injected from the injection hole 75 is 3.4 m / s or less.

[0043] 4 , when the injection holes 75 are projected onto the axial surface of the end ring 50 in the direction in which the injection holes 75 open, the portion of the axial surface of the end ring 50 onto which the injection holes 75 are projected, i.e., the projection portion 51, is a portion of the end ring 50 located above the central axis J. Therefore, for example, when fluid F or the like that has come into contact with the end ring 50 and then splashed into the housing 70 falls due to gravity, it can easily come into contact with the rotor 10, the stator 20, etc. This can further improve the cooling efficiency of the rotor 10 and the stator 20.

[0044] The projection 51 substantially coincides with the contact point IP on the axial surface of the end ring 50 with which the fluid F first comes into contact. In this embodiment, the projection 51 includes a radial center CE between the radial inner peripheral edge and the radial outer peripheral edge of the end ring 50. Therefore, compared to when the projection 51 is biased radially outward or radially inward from the center CE, it is easier to spread the fluid F in a balanced manner on the axial surface of the end ring 50. In this embodiment, the projection 51 has a substantially circular shape when viewed in the axial direction, with its central portion overlapping the center CE. In FIG. 4 , the radial center CE between the radial inner peripheral edge and the radial outer peripheral edge of the end ring 50 is indicated by a virtual circle with a dashed line.

[0045] In this embodiment, the direction in which the injection holes 75 open is not tilted in the circumferential direction. The radial direction in which the injection holes 75 open is tilted with respect to the axial direction, that is, the direction in which the injection holes 75 open when viewed in the up-down direction in this embodiment, is parallel to the axial direction and does not include a component facing in the circumferential direction.

[0046] The present invention is not limited to the above-described embodiment, and other configurations and methods may be adopted within the scope of the technical concept of the present invention. The injection angle φ of the injection hole is not particularly limited as long as it is greater than or equal to 10° and less than or equal to 50°. The injection hole may open toward any part of the axial surface of the end ring, as long as it opens toward the axial surface of the end ring. Only one fluid supply unit may be provided, or three or more fluid supply units may be provided. The fluid supply unit may have any configuration as long as it has an injection hole. The fluid supply unit may be formed by a pipe through which a fluid flows. In this case, the injection hole may be a through hole that penetrates the pipe from the inner circumferential surface to the outer circumferential surface. In this case, for example, the direction in which the through hole penetrates the pipe from the inner circumferential surface to the outer circumferential surface is the opening direction of the injection hole. Multiple injection holes opening toward the axial surface of one end ring may be provided. The flow velocity of the fluid injected from the injection hole is not particularly limited. The rotor may rotate at any rotational speed as long as it is rotatable at 20,000 rpm or higher, and may also rotate at a rotational speed lower than 20,000 rpm when the rotating electric machine is in use. The rotating electric machine may be a multi-phase motor other than a three-phase motor. The rotating electric machine may also be a generator. The use of the rotating electric machine is not particularly limited. For example, the rotating electric machine may be mounted on a vehicle for an application other than as a power source for the vehicle, or may be mounted on equipment other than a vehicle.

[0047] The present technology can be configured as follows: (1) A rotating electric machine including a rotor rotatable about a central axis, a stator facing the rotor with a gap therebetween, and a fluid supply unit that supplies a fluid to the rotor, wherein the rotor has a rotor core having a plurality of slots that are arranged in a circumferential direction and that penetrate the rotor in an axial direction, a plurality of conductor portions that are respectively arranged in the plurality of slots, and a pair of end rings that are located on one axial side of the rotor core and the other axial side of the rotor core, respectively, and that connect the plurality of conductor portions, the rotating electric machine being rotatable at a rotation speed of 20,000 rpm or more, the fluid supply unit having injection holes that open toward axial surfaces of the end rings, the opening direction of the injection holes being inclined radially inward with respect to the axial direction at a predetermined injection angle that is 10 degrees or more and 50 degrees or less. (2) The rotating electric machine described in (1), wherein the rotor is rotatable at a rotation speed of 30,000 rpm or more. (3) The rotating electric machine according to (2), wherein the injection angle is 45° or less. (4) The rotating electric machine according to (2) or (3), wherein the injection angle is 15° or more. (5) The rotating electric machine according to any one of (1) to (4), wherein a flow velocity of the fluid injected from the injection hole is 4.0 m / s or less. (6) The rotating electric machine according to any one of (1) to (5), wherein the central axis extends in a direction intersecting a vertical direction, and when the injection hole is projected onto an axial surface of the end ring in a direction in which the injection hole opens, a portion of the axial surface of the end ring onto which the injection hole is projected is a portion of the end ring located above the central axis. (7) A rotating electric machine according to any one of (1) to (6), wherein when the injection hole is projected onto the axial surface of the end ring in the direction in which the injection hole opens, the portion of the axial surface of the end ring onto which the injection hole is projected includes a radial center between the radial inner peripheral edge and the radial outer peripheral edge of the end ring.

[0048] The present inventors have obtained the new findings described in the above-described embodiments through computer simulations. The simulations were performed using, for example, known fluid analysis software installed on a computer. The simulations performed by the present inventors include a first simulation SIM1 to a sixth simulation SIM6.

[0049] As shown in FIG. 5 , the first simulation SIM1 to the fourth simulation SIM4 are simulations in which fluid F is sprayed onto the surface of the rotating plate 150 at a predetermined spray angle φ. The rotating plate 150 is plate-shaped with its surface facing up and down (Z-axis direction) and rotates around a rotation axis R1 extending in the up and down direction. In the first simulation SIM1 to the fourth simulation SIM4, the up and down direction corresponds to the axial direction in the above-described embodiment, and the radial direction around the rotation axis R1 corresponds to the radial direction in the above-described embodiment. In the first simulation SIM1 to the fourth simulation SIM4, the fluid F was sprayed onto the upper surface of the rotating plate 150 at the spray angle φ. The viscosity of the fluid F was 0.0421 Pa·s. The surface tension generated between the rotating plate 150 and the fluid F was 0.036 N / m.

[0050] In the first simulation SIM1, the rotation speed of the rotating plate 150 is 30,000 rpm. In the second simulation SIM2, the rotation speed of the rotating plate 150 is 25,000 rpm. In the third simulation SIM3, the rotation speed of the rotating plate 150 is 20,000 rpm. In the fourth simulation SIM4, the rotation speed of the rotating plate 150 is 15,000 rpm. The rotation speed of the rotating plate 150 corresponds to the rotation speed of the rotor 10 in the above-described embodiment. In the first simulation SIM1 to the fourth simulation SIM4, the flow velocity of the fluid F injected from the injection hole is 3.4 m / s.

[0051] In each of the first to fourth simulations SIM1 to SIM4, the spray angle φ was varied within a range from 0° to 75°, and the area of ​​the contact area FA of the fluid F spreading on the surface of the rotating plate 150 was measured for each case. The area of ​​the contact area FA was measured by encircling the area of ​​the fluid F steadily contacting the surface of the rotating plate 150 with a line, as shown in FIGS. 7 and 8 (described below), and measuring the area within the line. The results of the first simulation SIM1, the second simulation SIM2, the third simulation SIM3, and the fourth simulation SIM4 are shown in FIG. 6 . In the graph shown in FIG. 6 , the horizontal axis represents the spray angle φ [°], and the vertical axis represents the area ratio Rf. The area ratio Rf is the ratio of the area of ​​each contact area FA to the area of ​​the contact area FA when the spray angle φ in the first simulation SIM1 is 0°.

[0052] The results of the first simulation SIM1, the second simulation SIM2, and the third simulation SIM3 show that when the injection angle φ is 10°, the area ratio Rf is larger than when the injection angle φ is less than 10°. This confirms that when the rotation speed of the rotor 10 is 20,000 rpm or more, the area of ​​the contact area FA can be increased by setting the injection angle φ to 10° or more. The results of the first simulation SIM1, the second simulation SIM2, and the third simulation SIM3 show that when the injection angle φ exceeds 50°, the area ratio Rf drops sharply. This confirms that when the rotation speed of the rotor 10 is 20,000 rpm or more, the area of ​​the contact area FA can be increased by setting the injection angle φ to 50° or less. Therefore, it was confirmed that by setting the injection angle φ to be greater than or equal to 10° and less than or equal to 50°, the area of ​​the contact area FA can be suitably increased, even when the rotation speed of the rotor 10 is 20,000 rpm or more, and the cooling efficiency of the rotor 10 can be improved.

[0053] Comparing the results of the first to fourth simulations SIM1 to SIM4 shown in FIG. 6 , the fourth simulation SIM4, in which the rotation speed of the rotating plate 150 is 15,000 rpm, has a larger area ratio Rf and a smaller range of change in area ratio Rf with changes in injection angle φ compared to the first simulation SIM1, the second simulation SIM2, and the third simulation SIM3, in which the rotation speed of the rotating plate 150 is 20,000 rpm or higher. In particular, the change in area ratio Rf in the fourth simulation SIM4 does not tend to decrease when the injection angle φ exceeds 50°. On the other hand, in the simulations SIM1, SIM2, and SIM3, in which the rotation speed of the rotating plate 150 is 20,000 rpm or higher, the range of change in area ratio Rf with respect to injection angle φ is larger than the range of change in area ratio Rf with respect to injection angle φ in the fourth simulation SIM4. Furthermore, in each of the simulations SIM1, SIM2, and SIM3, the area ratio Rf increases when the injection angle φ is in the range of 10° or more and 50° or less, and decreases when the injection angle φ exceeds 50°. From these results, it can be seen that, for example, when the rotation speed of the rotor 10 is 15,000 rpm, even if the injection angle φ is less than 10° or more than 50°, the area ratio Rf does not change much compared to when the injection angle φ is 10° or more and 50° or less, whereas when the rotation speed of the rotor 10 is 20,000 rpm or more, when the injection angle φ is less than 10° or more than 50°, the area of ​​the contact area FA decreases, and the cooling efficiency of the rotor 10 decreases. That is, it was confirmed that in a rotating electrical machine 100 in which the rotor 10 can rotate at a rotation speed of 20,000 rpm or more, by setting the injection angle φ to 10° or more and 50° or less, the area of ​​the contact area FA can be increased both when the rotation speed of the rotor 10 is lower than 20,000 rpm and when the rotation speed of the rotor 10 is 20,000 rpm or more. Therefore, it was confirmed that in a rotating electrical machine 100 in which the rotor 10 can rotate at a rotation speed of 20,000 rpm or more, by setting the injection angle φ to 10° or more and 50° or less, the cooling efficiency of the rotor 10 can be improved regardless of the rotation speed of the rotor 10.

[0054] The results of the first simulation SIM1, the second simulation SIM2, and the third simulation SIM3 shown in FIG. 6 reveal that when the injection angle φ is approximately 55° to 60° or greater, the area ratio Rf increases as the injection angle φ increases. In FIG. 6 , the area ratio Rf at an injection angle φ of 75° is approximately equal to or greater than the area ratio Rf at injection angles φ in the range of 10° to 50°. This suggests that, similar to injection angles φ in the range of 10° to 50°, injection angles φ of 75° or greater can improve the cooling efficiency of the rotor 10 regardless of the rotation speed of the rotor 10. However, as shown in FIG. 1 , the axial ends of the coils 22 tend to be located radially outward of the end rings 50. Therefore, when the injection angle φ is 75° or greater, the coils 22 obstruct the flow of the fluid F injected from the injection holes 75 toward the end rings 50, making it difficult for the fluid F to be sprayed toward the end rings 50. Therefore, in the rotating electrical machine 100, even if the injection angle φ is 75° or more, the area of ​​the contact area FA cannot be increased, and the cooling efficiency of the rotor 10 may not be sufficiently increased. In contrast, if the injection angle φ is set to 10° or more and 50° or less, the injection holes 75 can be positioned so that they are not obstructed by the coil 22, and the area of ​​the contact area FA can be increased to a level equal to or greater than that when the injection angle φ is 75° or more. Therefore, by setting the injection angle φ to 10° or more and 50° or less, the cooling efficiency of the rotor 10 can be suitably improved.

[0055] The results of the first simulation SIM1, the second simulation SIM2, and the third simulation SIM3 shown in FIG. 6 show that the range of change in the area ratio Rf with respect to the injection angle φ is larger in the first simulation SIM1 than in the second simulation SIM2 and the third simulation SIM3. For example, when the injection angle φ is set to 55° in the first simulation SIM1, the area ratio Rf is significantly reduced compared to when the injection angle φ is set to 50°. On the other hand, in the second simulation SIM2 and the third simulation SIM3, even when the injection angle φ is set to 55°, the area ratio Rf is reduced compared to when the injection angle φ is set to 50°, but the range of the reduction is smaller than in the first simulation SIM1. This shows that when the rotation speed of the rotor 10 is 30,000 rpm or higher, when the injection angle φ is outside the range of 10° to 50°, the area of ​​the contact area FA is significantly reduced, and the cooling efficiency of the rotor 10 is significantly reduced. Therefore, it was confirmed that the effect of improving the cooling efficiency of the rotor 10 by setting the injection angle φ to be greater than or equal to 10° and less than or equal to 50° is particularly useful when the rotor 10 is capable of rotating at a rotation speed of 30,000 rpm or more.

[0056] 6, it can be seen that in the first simulation SIM1, when the injection angle φ is changed from 45° to 50°, the area ratio Rf decreases slightly, unlike in the second simulation SIM2 and the third simulation SIM3. This confirms that in a rotating electrical machine 100 in which the rotor 10 can rotate at a rotation speed of 30,000 rpm or more, the area of ​​the contact area FA can be more suitably increased and the cooling efficiency of the rotor 10 can be more suitably improved by setting the injection angle φ to 45° or less.

[0057] 6 shows that in the first simulation SIM1, when the injection angle φ is changed from 10° to 15°, the area ratio Rf increases significantly compared to the second simulation SIM2 and the third simulation SIM3, etc. This confirms that in a rotating electrical machine 100 in which the rotor 10 can rotate at a rotation speed of 30,000 rpm or more, the area of ​​the contact area FA can be more suitably increased and the cooling efficiency of the rotor 10 can be more suitably improved by setting the injection angle φ to 15° or more.

[0058] 7 and 8 show the contact area FA for each injection angle φ in the first simulation SIM1. In Fig. 7 and Fig. 8, the rotation direction of the rotating plate 150 is indicated by an arrow θ, similar to the rotation direction of the rotor 10 in Fig. 4. Fig. 7 shows the contact area FA when the injection angle φ in the first simulation SIM1 is 10°, 15°, 30°, and 45°. Fig. 8 shows the contact area FA when the injection angle φ in the first simulation SIM1 is 15°, 30°, 45°, 60°, and 70°.

[0059] 7, the radially outer edge of the contact area FA is located closer to the front (+θ side) in the rotation direction of the rotating plate 150 when the injection angle φ is 15°, 30°, or 45° than when the injection angle φ is 10°. In other words, when the injection angle φ is 15°, 30°, or 45°, the distance that the fluid F travels forward in the rotation direction on the surface of the rotating plate 150 before scattering from the radially outer edge of the rotating plate 150 is longer than when the injection angle φ is 10°. Therefore, in the first simulation SIM1, when the injection angle φ is 15° or more, it is considered that the area of ​​the contact area FA is larger than when the injection angle φ is 10°.

[0060] 8, in the first simulation SIM1, when the injection angle φ is 60°, the end of the radial outer edge of the contact area FA on the front side in the direction of rotation (+θ side) is located on the rear side in the direction of rotation (−θ side) compared to when the injection angle φ is 15°, 30°, or 45°. Therefore, when the injection angle φ is 60°, it is considered that the area of ​​the contact area FA is smaller than when the injection angle φ is 15°, 30°, or 45°.

[0061] In the first simulation SIM1, when the injection angle φ is 70°, as in the case where the injection angle φ is 60°, the end of the radial outer edge of the contact area FA on the forward side (+θ side) in the direction of rotation is located further back in the direction of rotation (−θ side) than when the injection angle φ is 15°, 30°, or 45°. However, when the injection angle φ is 70°, the inclination of the injection holes 75 with respect to the direction perpendicular to the plate surface of the rotating plate 150 becomes larger, and the area of ​​the portion where the fluid F first comes into contact with the rotating plate 150 becomes larger. As a result, it is thought that when the injection angle φ is 70°, the area of ​​the contact area FA is larger than when the injection angle φ is 60°.

[0062] The fifth simulation SIM5, like the first simulation SIM1 to the fourth simulation SIM4, is a simulation in which the fluid F is sprayed at a predetermined spray angle φ against the plate surface of the rotating plate 150 shown in Fig. 5. In the fifth simulation SIM5, the flow velocity of the fluid F sprayed from the spray holes is 6.8 m / s. The other conditions in the fifth simulation SIM5 are the same as those in the first simulation SIM1.

[0063] In the fifth simulation SIM5, the spray angle φ was also varied within a range from 0° to 75°, and the area of ​​the contact area FA of the fluid F spreading on the surface of the rotating plate 150 was measured for each case. The results of the first simulation SIM1 and the fifth simulation SIM5 are shown in Fig. 9. In the graph shown in Fig. 9, the horizontal axis represents the spray angle φ [°], and the vertical axis represents the area ratio Rf.

[0064] As shown in FIG. 9 , the fifth simulation SIM5 also showed a similar trend to the first simulation SIM1 in the change in the area ratio Rf with respect to the injection angle φ. That is, the fifth simulation SIM5 also confirmed that the area ratio Rf increased when the injection angle φ was 10° or greater and 50° or less. This confirmed that even when the flow velocity of the fluid F injected from the injection hole 75 changed, the area of ​​the contact area FA could be increased by keeping the injection angle φ 10° or greater and 50° or less. On the other hand, FIG. 9 shows that the first simulation SIM1 showed a larger change in the area ratio Rf with respect to the injection angle φ than the fifth simulation SIM5. That is, in the fifth simulation SIM5, in which the flow velocity of the fluid F was 6.8 m / s, which was faster than 4.0 m / s, the area ratio Rf was unlikely to decrease significantly even when the injection angle φ was outside the range of 10° or greater and 50° or less. On the other hand, in the first simulation SIM1 where the flow velocity of the fluid F is 3.4 m / s, which is 4.0 m / s or less, the area ratio Rf tends to decrease significantly when the injection angle φ is outside the range of 10° to 50°. Therefore, it was confirmed that when the flow velocity of the fluid F is 4.0 m / s or less, by setting the injection angle φ to 10° to 50°, the area of ​​the contact area FA can be increased and the cooling efficiency of the rotor 10 can be more effectively improved.

[0065] As shown in FIG. 10 , the sixth simulation SIM6 is a simulation in which fluid F is sprayed onto the plate surface of the rotating plate 250 at a predetermined spray angle φ. The rotating plate 250 is plate-shaped with its plate surface facing perpendicular to the vertical direction (Z-axis direction) and rotates around a rotation axis R2 extending in a direction perpendicular to the vertical direction, i.e., the left-right direction in FIG. 10 . In FIG. 10 , the left-right direction corresponds to the axial direction in the above-described embodiment, and the radial direction centered on the rotation axis R2 corresponds to the radial direction in the above-described embodiment. In the sixth simulation SIM6, fluid F was sprayed onto the plate surface on the right side of the rotating plate 250 in FIG. 10 at a spray angle φ. The conditions for the sixth simulation SIM6 were the same as those for the first simulation SIM1, except for the orientation of the rotating plate 250.

[0066] The results of the first simulation SIM1 and the sixth simulation SIM6 are shown in FIG. 11 . In the graph shown in FIG. 11 , the horizontal axis represents the injection angle φ [°], and the vertical axis represents the area ratio Rf. As shown in FIG. 11 , the sixth simulation SIM6 also showed a similar trend to the first simulation SIM1 in the change in the area ratio Rf with respect to the injection angle φ. This confirms that, regardless of the orientation of the rotor 10 relative to the vertical direction, the area of ​​the contact area FA can be increased and the cooling efficiency of the rotor 10 can be improved by setting the injection angle φ to be greater than or equal to 10° and less than or equal to 50°. In other words, even if the rotor 10 is positioned such that the axial direction extends in a direction intersecting the vertical direction as in the above-described embodiment, it was confirmed that similar results to those obtained in the first simulation SIM1 to the fifth simulation SIM5 can be obtained depending on the rotation speed of the rotor 10 and the flow velocity of the fluid F injected from the injection holes 75.

[0067] In the first simulation SIM1 to the sixth simulation SIM6 described above, the axial position of the injection hole 75 was set to be the same axial distance away from the plate surface of the rotating plate 150, 250 onto which the fluid F was sprayed, regardless of the injection angle φ. In other words, in the first simulation SIM1 to the sixth simulation SIM6, the greater the injection angle φ, the greater the shortest distance from the injection hole 75 to the plate surface of the rotating plate 150, 250. The inventors of the present application have verified through another simulation that even if the shortest distance from the injection hole 75 to the plate surface of the rotating plate 150, 250 changes, as long as the momentum of the fluid F at the time when it reaches the plate surface of the rotating plate 150, 250 is maintained at a certain level or above, this has almost no effect on the change in the area of ​​the contact area FA.

[0068] The configurations and methods described in this specification can be combined as appropriate within the scope of not being mutually contradictory.

[0069] 10...rotor, 11...rotor core, 20...stator, 30...slot, 40...conductor portion, 50, 50a, 50b...end ring, 75...injection hole, 77, 77a, 77b...fluid supply portion, 100...rotating electric machine, CE...center, F...fluid, J...central axis, φ...injection angle

Claims

1. A rotary electric machine comprising: a rotor rotatable about a central axis; a stator facing the rotor with a gap therebetween; and a fluid supply unit that supplies fluid to the rotor, wherein the rotor has: a rotor core having a plurality of slots that are arranged circumferentially and penetrate the axial direction; a plurality of conductor portions that are respectively arranged in the plurality of slots; and a pair of end rings that are located on one axial side of the rotor core and on the other axial side of the rotor core, respectively, and connect the plurality of conductor portions; and the rotary electric machine is rotatable at a rotation speed of 20,000 rpm or more; the fluid supply unit has injection holes that open toward the axial surface of the end ring, the opening direction of the injection holes being inclined radially inward with respect to the axial direction at a predetermined injection angle, and the injection angle is 10° or more and 50° or less.

2. A rotating electric machine according to claim 1, wherein the rotor is rotatable at a rotational speed of 30,000 rpm or more.

3. A rotating electric machine according to claim 2, wherein the injection angle is 45° or less.

4. A rotating electric machine according to claim 2, wherein the injection angle is 15° or more.

5. A rotating electric machine according to any one of claims 1 to 4, wherein the flow velocity of the fluid injected from the injection hole is 4.0 m / s or less.

6. A rotating electric machine according to any one of claims 1 to 4, wherein the central axis extends in a direction intersecting the vertical direction, and when the injection hole is projected onto the axial surface of the end ring in the direction in which the injection hole opens, the portion of the axial surface of the end ring onto which the injection hole is projected is a portion of the end ring located above the central axis.

7. A rotating electric machine according to any one of claims 1 to 4, wherein when the injection hole is projected onto the axial surface of the end ring in the direction in which the injection hole opens, the portion of the axial surface of the end ring onto which the injection hole is projected includes the radial center between the radial inner peripheral edge and the radial outer peripheral edge of the end ring.

Images