JP2008312321A - Rotor and rotating electric machine - Google Patents

Abstract

Provided are a rotor and a rotating electrical machine that can reduce stress concentration in a rotor that rotates at high speed.
A rotor according to the present invention includes a rotating shaft and a rotor core. The inner peripheral surface of the through hole of the rotor core includes concave inner peripheral surfaces 40 and 140 that form concave portions that are located on both sides of the key portion 42 and are recessed in a direction away from the outer peripheral surface of the rotary shaft. A cross section perpendicular to the central axis of the rotating shaft on the inner peripheral surface of the recess has a first arc portion C1 having a first radius of curvature and a tangential direction continuing to the side surface of the key portion, and a second radius of curvature. And a second arc portion C2 continuous in the tangential direction of the first arc portion. The second radius of curvature is larger than the first radius of curvature, and a line L2 connecting the center of the second radius of curvature and the central axis of the rotary shaft is the center of the first radius of curvature and the central axis of the rotary shaft. Is located at a position farther from the side surface of the key part than the line L1 connecting.
[Selection] Figure 15

Description

  The present invention relates to a rotor and a rotating electrical machine, and more particularly to a rotor and a rotating electrical machine in which a key formed on a rotor core is fitted in a key groove of a rotating shaft.

  Conventionally, various connection structures between a rotor core and a rotating shaft in a rotor of a rotating electrical machine have been proposed.

  For example, in the rotor described in Patent Document 1 (Japanese Patent Application Laid-Open No. 2004-32943), a key member extending toward the rotor center on the inner wall of the rotor and a key groove formed on the outer wall of the shaft are provided. Have. The keyway and the key member are formed so that rotation in the other circumferential direction with respect to one is allowed in the process in which the two fit together.

  In this rotor, the stress generated between the rotor core and the rotating shaft when the rotor core and the rotating shaft are fitted is reduced.

  The rotor described in Patent Document 2 (Japanese Patent Application Laid-Open No. 2006-217770) includes a rotor core formed by laminating a plurality of thin steel plates having through holes, and a fitting hole formed in the center of the rotor core. And a shaft to be press-fitted into.

  The rotor core is formed by laminating the thin steel plates so that through holes are formed in the thin steel plates, and the small diameter portions and the large diameter portions of the through holes are alternately arranged in the axial direction. Further, the rotor of the motor is configured by press-fitting a shaft having a concavo-convex portion on the outer peripheral surface thereof into the insertion hole of the rotor core.

Patent Document 3 (Japanese Patent Publication No. 4-52056) discloses a structure that relieves stress at a connecting portion between a magnetic core and a yoke.
JP 2004-32943 A JP 2006-217770 A Japanese Patent Publication No. 4-52056

  A motor used in a so-called hybrid vehicle rotates at a very high speed. One example is one that rotates at 13500 rpm. In such high-speed rotation, stress concentration at a location adjacent to the key portion of the rotor due to the influence of centrifugal force applied to the rotor becomes a problem.

  As described above, Patent Document 1 discloses a structure that alleviates stress concentration on a key part in a rotor having a structure in which a key part and a key groove are fitted. However, considering the influence of the centrifugal force in the high-speed rotation as described above, further relaxation of stress concentration is desired.

  Further, Patent Document 2 and Patent Document 3 do not disclose a structure that relieves stress concentration at the connection portion between the rotor core and the shaft.

Accordingly, an object of the present invention is to provide a rotor and a rotating electrical machine that can reduce stress concentration in a rotor that rotates at a high speed.

  According to the rotor based on this invention, the rotary shaft having a cylindrical outer peripheral surface and provided with a keyway, the through-hole through which the rotary shaft passes are provided, and the inner peripheral surface of the through-hole And a rotor core including a key portion that protrudes from the key groove and is fitted into the key groove. An inner peripheral surface of the through hole is formed in a cylindrical shape centering on a central axis of the rotary shaft, and is disposed on both sides of the key portion and a cylindrical inner peripheral surface along the outer peripheral surface of the rotary shaft. And a recess inner peripheral surface constituting a recess recessed in a direction away from the outer peripheral surface. The cross section of the inner peripheral surface of the recess perpendicular to the central axis of the rotating shaft has a first arcuate portion having a first radius of curvature and a tangential direction continuing to a side surface of the key portion, and a second radius of curvature. And a second arc portion continuous in the tangential direction of the first arc portion. The second radius of curvature is larger than the first radius of curvature, and the line connecting the center of the second radius of curvature and the central axis of the rotary shaft is the center of the first radius of curvature and the rotary shaft. It is located in the position away from the side of the key part from the line which connects with the central axis.

  In the rotor, the second radius of curvature is preferably 1.5 times or more and 2.5 times or less of the first radius of curvature.

  In the rotor, more preferably, a cross section of the inner peripheral surface of the concave portion perpendicular to the central axis of the rotary shaft has a linear portion continuous in a tangential direction of the second arc portion, the linear portion, and the cylindrical inner periphery. And a third arc portion continuous in the tangential direction of the surface.

  You may comprise a rotary electric machine by providing the said rotor.

  According to the rotor and the rotating electrical machine according to the present invention, stress concentration can be reduced in the rotor rotating at high speed.

  A rotor and a rotating electrical machine according to the present embodiment will be described with reference to FIGS. FIG. 1 is a cross-sectional view schematically showing a motor mounted on a hybrid vehicle. A hybrid vehicle equipped with the motor in the figure uses an internal combustion engine such as a gasoline engine or a diesel engine and a rechargeable secondary battery (battery) as power sources.

  As shown in FIG. 1, the motor (rotary electric machine) 100 includes an IPM rotor (rotor) 10 and a stator 50 disposed on the outer periphery of the IPM rotor 10. The IPM rotor 10 includes a rotating shaft 58 that rotates about a central axis 101.

  The IPM rotor 10 includes a rotor core 20, a permanent magnet 31 embedded in the rotor core 20, and a holding member (not shown) that holds the permanent magnet 31 with respect to the rotor core 20. The rotor core 20 has a shape extending in a cylindrical shape along the central axis 101. The rotor core 20 includes a plurality of electromagnetic steel plates 21 stacked in the axial direction of the central shaft 101.

  Stator 50 includes a stator core 55 and a coil 51 wound around stator core 55. The stator core 55 includes a plurality of electromagnetic steel plates 52 stacked in the axial direction of the central shaft 101. The rotor core 20 and the stator core 55 are not limited to electromagnetic steel plates, and may be formed of a magnetic material such as a dust core, for example.

The coil 51 is electrically connected to the control device 70 by a three-phase cable 60. 3
The phase cable 60 includes a U-phase cable 61, a V-phase cable 62, and a W-phase cable 63. The coil 51 includes a U-phase coil, a V-phase coil, and a W-phase coil, and a U-phase cable 61, a V-phase cable 62, and a W-phase cable 63 are connected to terminals of these three coils, respectively.

  A torque command value to be output from the motor 100 is sent to the control device 70 from an ECU (Electrical Control Unit) 80 mounted on the hybrid vehicle. The control device 70 generates a motor control current for outputting the torque specified by the torque command value, and supplies the motor control current to the coil 51 via the three-phase cable 60.

  FIG. 2 is an end view of the stator taken along the line II-II in FIG. In the drawing, the winding structure of the motor is schematically shown.

  As shown in FIGS. 1 and 2, the stator core 55 has a cylindrical shape extending along the central axis 101. The stator core 55 includes a plurality of teeth 1 arranged in the circumferential direction around the central axis 101 on the inner peripheral surface. In the present embodiment, the stator core 55 has 48 teeth 1.

  Coil 51 includes coils 510 to 517 constituting a U-phase coil, coils 520 to 527 constituting a V-phase coil, and coils 530 to 537 constituting a W-phase coil. Each of coils 510-517, 520-527, 530-537 is wound around a plurality of teeth 1 that are continuous in the circumferential direction. Coils 510 to 517 are arranged on the outermost periphery. The coils 520 to 527 are arranged inside the coils 510 to 517 at positions shifted from the coils 510 to 517 by a certain phase in the circumferential direction. The coils 530 to 537 are arranged inside the coils 520 to 527 at positions shifted from the coils 520 to 527 by a certain phase in the circumferential direction.

  The coils 510 to 513 are connected in series, and one end thereof is a terminal U1 and the other end is a neutral point UN1. The coils 514 to 517 are connected in series, and one end thereof is a terminal U2 and the other end is a neutral point UN2.

  The coils 520 to 523 are connected in series, and one end thereof is a terminal V1 and the other end is a neutral point VN1. The coils 524 to 527 are connected in series, and one end thereof is a terminal V2 and the other end is a neutral point VN2.

  Coils 530 to 533 are connected in series, and one end thereof is terminal W1 and the other end is neutral point WN1. The coils 534 to 537 are connected in series, and one end thereof is a terminal W2, and the other end is a neutral point WN2.

  The neutral points UN1, UN2, VN1, VN2, WN1, and WN2 are commonly connected to one point. Terminals U1 and U2 are connected to a U-phase cable 61 of the three-phase cable 60, terminals V1 and V2 are connected to a V-phase cable 62, and terminals W1 and W2 are connected to a W-phase cable 63.

  FIG. 3 is a cross-sectional view of the motor along the line III-III in FIG. As shown in FIG. 3, a plurality of permanent magnets 31 are arranged along the circumferential direction around the central axis 101. In the present embodiment, eight permanent magnets 31 are provided. The permanent magnet 31 has a substantially rectangular parallelepiped shape. The permanent magnet 31 has a substantially rectangular shape when viewed from the axial direction of the central shaft 101.

  The permanent magnets 31A, 31C, 31E, 31G are arranged so that the outer peripheral side of the rotor core 20 is an N pole. The permanent magnets 31B, 31D, 31F, and 31H are arranged so that the outer peripheral side of the rotor core 20 is an S pole. As described above, the permanent magnet 31 is magnetized in the radial direction around the central axis 101, and is arranged so that the polarity of the magnet is reversed between adjacent magnets. Coils 510 to 517, 520 to 527, and 530 to 537 shown in FIG. 2 are arranged to face these permanent magnets 31 (31A to 31H).

  The number of teeth 1 is determined to be an integral multiple of the number of permanent magnets 31 embedded in the rotor core 20. The number of teeth 1 and permanent magnets 31 is not limited to the number given in the present embodiment.

  FIG. 4 is a cross-sectional view showing an engagement portion between the rotor core and the rotating shaft. As shown in FIG. 4, the rotary shaft 58 is formed in a columnar shape, and a key groove 58a extending in the axial direction is formed on the peripheral surface thereof.

  The rotor core 20 is formed in a substantially annular shape, and a through hole 20a extending in the axial direction is formed at the center thereof.

  A key portion 42 extending in the axial direction is formed on the inner peripheral surface of the rotor core 20 that defines the through hole 20a. The key part 42 protrudes inward in the radial direction, and can be fitted into the key groove 58a.

  The inner peripheral surface of the rotor core 20 that defines the through-hole 20 a is configured in a cylindrical shape centered on the central axis of the rotary shaft 58, and is mainly configured by a cylindrical inner peripheral surface 22 along the outer peripheral surface of the rotary shaft 58.

  A portion of the inner peripheral surface of the rotor core 20 that defines the through-hole 20 a adjacent to the key portion 42 is configured by concave inner peripheral surfaces 40 and 140 that are recessed outward in the radial direction of the rotor core 20. The recess inner peripheral surfaces 40 and 140 are provided adjacent to both sides of the key portion 42 and are recessed so as to be separated from the peripheral surface of the rotary shaft 58 inserted into the rotor core 20.

  The concave inner peripheral surfaces 40 and 140 are separated from the surface of the rotary shaft 58 so that stress does not act directly on the rotary shaft 58.

  FIG. 5 is an exploded view showing the structure of the engaging portion between the rotor core and the rotating shaft in the comparative example, and FIG. 6 is an exploded view showing the structure of the engaging portion between the rotor core and the rotating shaft in the present embodiment. is there. The reason why the concave inner peripheral surfaces 40 and 140 are required will be described with reference to FIGS. 5 and 6.

  In order to relieve stress concentration at the connecting portion between the key portion 42 provided on the rotor core 20 and the inner peripheral surface of the rotor core 20 adjacent to the key portion 42, it is necessary to provide a stress relaxation curved surface at the base portion of the key portion 42. is there. In other words, it is necessary to connect the side surface of the key portion 42 and the inner peripheral surface of the rotor core 20 with a curved surface.

  Here, when the stress relaxation curved surface S is provided, as shown in FIG. 5, the stress relaxation curved surface S is provided so as to protrude inside the extension line of the cylindrical inner peripheral surface 22 constituting the through hole 20 a of the rotor core 20, and FIG. As shown, the base portion of the key portion 42 is recessed outside the extension line of the cylindrical inner peripheral surface 22 to form the concave inner peripheral surfaces 40 and 140, and the concave inner peripheral surfaces 40 and 140 are connected to the stress relaxation curved surface S. It may be the case.

  As shown in FIG. 5, in the case where the stress relaxation curved surface S is provided inside the extension line of the cylindrical inner peripheral surface 22, in order to avoid interference with a portion adjacent to the key groove 58 a on the outer peripheral surface of the rotary shaft 58. It is necessary to provide chamfered portions 59 on both sides of the key groove 58a. Here, in order to provide the chamfered portion 59 on the rotating shaft 58, it is necessary to cut both sides of the key groove 58 a so as to extend over the entire length of the rotating shaft 58. This is an additional processing step and increases the manufacturing cost.

  As shown in FIG. 6, when a curved surface is provided outside the extended line of the circular inner peripheral surface of the through hole 20 a of the rotor core 20, further processing of the rotating shaft is not necessary. Further, since the rotor core 20 is formed by pressing, the number of processing steps does not increase by providing the recesses 40 and 140.

  For the reasons described above, when the stress relaxation curved surfaces S are formed on both sides of the key groove 58a, it is preferable to provide concave inner peripheral surfaces 40 and 140 as shown in FIG.

  In order to identify the shape with the smallest stress concentration when forming the recess inner peripheral surfaces 40 and 140 that are stress relaxation curved surfaces on both sides of the key groove 58a, the inventor sets various models and performs stress analysis by numerical analysis. Was calculated. Specifically, the centrifugal force generated in the rotating rotor rotating at a high speed was calculated, and the stress generated on the inner peripheral surfaces 40 and 140 of various shapes and the periphery by the centrifugal force was calculated.

  FIG. 7 is a diagram showing the shape of the basic model, and FIG. 8 is a diagram showing the stress distribution of the basic model. In the basic model shown in FIG. 7, concave inner peripheral surfaces 40 and 140 are provided on both sides of the key portion 42. The recess inner peripheral surface 40 and the recess inner peripheral surface 140 have symmetrical shapes with the key portion 42 interposed therebetween.

  The part connected to the side surface of the key part 42 of the recessed inner peripheral surfaces 40 and 140 is formed by a curved surface C1 in contact with the curvature circle R1. A plane portion P1 is connected in the tangential direction of the curved surface C1. A curved surface C3 is further connected to the plane portion P1. The curved surface C3 is a curved surface in contact with the curvature circle R3. Further, the plane portion P1 is located in the tangential direction of the curved surface C3. A cylindrical inner peripheral surface 22 is connected in the tangential direction of the curved surface C3.

  Specific dimensions of the basic model shown in FIG. 7 are as follows. The radius of the through hole 20a of the rotor core 20 is 54 mm. The length from the deepest part of the concave inner peripheral surfaces 40 and 140 to the center of the cylindrical inner peripheral surface 22 is 55 mm. The radius of the curvature circle R1 is 1 mm. The radius of the curvature circle R3 is 3 mm. The angle formed by the side surface of the key portion 42 and the flat portion P1 is 60 °.

  When the rotor core 20 having such a shape was rotated at 13500 rpm, the maximum stress was 515 MPa on the concave inner peripheral surface 40 and 517 MPa on the concave inner peripheral surface 140 as shown in FIG.

  Next, in order to reduce this maximum stress, a model in which the radius of the curvature circle R1 was enlarged was created. FIG. 9 is a diagram showing a model in which the radius of the curvature circle R1 is enlarged, and FIG. 10 is a diagram showing a stress distribution of the model in which the radius of the curvature circle R1 is enlarged.

  In the model shown in FIG. 9, the radius of the curvature circle R1 is 2 mm, and the length from the deepest part of the concave inner peripheral surfaces 40 and 140 to the center of the cylindrical inner peripheral surface 22 is 56 mm.

  As a result, as shown in FIG. 10, the maximum stress was 506 MPa on the inner circumferential surface 40 of the recess and 505 MPa on the inner circumferential surface 140 of the recess. Compared with the basic model shown in FIG. 7, the maximum stress decreased, but no significant improvement was observed.

  Next, a model was created in which a curved surface C2 in contact with a curvature circle R2 having a radius larger than that of the curvature circle R1 was formed between the curved surface C1 in contact with the curvature circle R1 and the plane portion P1.

  FIG. 11 is a diagram showing a model in which the key portion and the plane portion are configured by two curved surfaces, and FIG. 12 is a graph showing the stress distribution of the model in which the key portion and the plane portion are configured by two curved surfaces. FIG. In the model shown in FIG. 11, the line L2 connecting the center of the curvature circle R2 and the center of the through hole 20a is closer to the key part 42 than the line L1 connecting the center of the curvature circle R1 and the center of the through hole 20a. Show.

  In this case, the length of the curved surface C2 having a large curvature radius is small. At this time, the radius of the curvature circle R1 is 1 mm, and the radius of the curvature circle R2 is 2 mm. The radius of the curvature circle R2 is twice the radius of the curvature circle R1.

  As shown in FIG. 12, the maximum stress in this model was 511 MPa in both the concave inner peripheral surface 40 and the concave inner peripheral surface 140. Although the maximum stress decreased compared with the basic model shown in FIG. 7, no significant improvement was still observed.

  FIG. 13 is a diagram illustrating a model configured with two curved surfaces between the key portion and the plane portion, and FIG. 14 illustrates a stress distribution of the model configured with two curved surfaces between the key portion and the plane portion. FIG. The model shown in FIG. 13 shows a case where a line L2 connecting the center of the curvature circle R2 and the center of the through hole 20a overlaps a line L1 connecting the center of the curvature circle R1 and the center of the through hole 20a.

The radii of the curvature circle R1 and the curvature circle R2 are the same as those of the model shown in FIG.
As shown in FIG. 14, the maximum stress in this model was 480 MPa in both the concave inner peripheral surface 40 and the concave inner peripheral surface 140. The maximum stress was clearly reduced when compared with the basic model shown in FIG.

  FIG. 15 is a diagram illustrating a model configured with two curved surfaces between the key portion and the plane portion, and FIG. 16 illustrates a stress distribution of the model configured with two curved surfaces between the key portion and the plane portion. FIG. The model shown in FIG. 15 shows a case where a line L2 connecting the center of the curvature circle R2 and the center of the through hole 20a overlaps a line L1 connecting the center of the curvature circle R1 and the center of the through hole 20a.

The radii of the curvature circle R1 and the curvature circle R2 are the same as those of the model shown in FIG.
As shown in FIG. 16, the maximum stress in this model was 434 MPa in both the recess inner peripheral surface 40 and the recess inner peripheral surface 140. Compared with the basic model shown in FIG. 7, the maximum stress was significantly reduced.

  When the above five models are compared, the model shown in FIG. 15 has the most favorable results with the least stress concentration. That is, in order to reduce the stress concentration, the cross section of the recess inner peripheral surfaces 40, 140 perpendicular to the central axis 101 of the rotary shaft 58 has a first radius of curvature, and the tangential direction is on the side surface of the key portion 42. A first arc portion that is continuous, and a second arc portion that has a second radius of curvature and that is continuous in a tangential direction of the first arc portion, and the second radius of curvature is greater than the first radius of curvature. The line L2 that is large and connects the center of the second radius of curvature and the central axis of the rotary shaft is farther from the side surface of the key portion 42 than the line L1 that connects the center of the first radius of curvature and the central axis of the rotary shaft. It has been found that it is preferable to configure it to be located at a different position.

  At this time, it was found that the second radius of curvature is preferably 1.5 times or more and 2.5 times or less, and most preferably 2 times the first radius of curvature. If it is less than 1.5 times, the effect of suppressing stress concentration is not sufficient, and if it exceeds 2.5 times, it becomes difficult to smoothly connect to the cylindrical inner peripheral surface 22.

  In the present embodiment, since the curved surface C2 in contact with the curvature circle R2 and the cylindrical inner peripheral surface 22 are constituted by the plane portion P1 positioned in the tangential direction of the curved surface C2 and the curved surface C3, Can be connected smoothly. The radius of the curvature circle R3 with which the curved surface C3 is in contact is preferably as large as possible in order to avoid stress concentration.

  By configuring as described above, the maximum stress can be reduced. Thereby, the motor which can respond to higher rotation can be comprised.

  In addition, the said embodiment disclosed this time is an illustration in all the points, Comprising: It does not become the basis of limited interpretation. Therefore, the technical scope of the present invention is not interpreted only by the above-described embodiments, but is defined based on the description of the claims. Further, all modifications within the meaning and scope equivalent to the scope of the claims are included.

It is sectional drawing which shows typically the motor mounted in the hybrid vehicle in embodiment based on this invention. FIG. 2 is an end view of the stator taken along line II-II in FIG. 1 in the embodiment based on the present invention. FIG. 3 is a cross-sectional view of the motor along the line III-III in FIG. 1 in the embodiment based on the present invention. It is sectional drawing which shows the engaging part of a rotor core and a rotating shaft in embodiment based on this invention. It is an exploded view which shows the structure of the engaging part of the rotor core of a comparative example, and a rotating shaft. It is an exploded view which shows the structure of the engaging part of the rotor core and rotary shaft in embodiment based on this invention. It is a figure which shows the shape of the basic model of numerical analysis. It is a figure which shows the stress distribution of a basic model. It is a figure which shows the model of the numerical analysis which expanded the radius of curvature circle R1. It is a figure which shows the stress distribution in the model of the numerical analysis which expanded the radius of curvature circle R1. It is a figure which shows the model of the numerical analysis which comprised between two curved surfaces between the key part and the plane part. It is a figure which shows the stress distribution in the model of the numerical analysis which comprised between the key part and the plane part with two curved surfaces. It is a figure which shows the model of the numerical analysis which comprised between two curved surfaces between the key part and the plane part. It is a figure which shows the stress distribution in the model of the numerical analysis which comprised between the key part and the plane part with two curved surfaces. It is a figure which shows the model of the numerical analysis which comprised between two curved surfaces between the key part and the plane part. It is a figure which shows the stress distribution in the model of the numerical analysis which comprised between the key part and the plane part with two curved surfaces.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Teeth, 10 Rotor, 20 Rotor core, 20a Through-hole, 21 Electrical steel plate, 22 Cylindrical inner peripheral surface, 31 Permanent magnet, 40,140 Recessed inner peripheral surface, 42 Key part, 50
Stator, 51 Coil, 52 Magnetic steel plate, 55 Stator core, 58 Rotating shaft, 58a Keyway, 59 Chamfer, 60 3-phase cable, 61 U-phase cable, 62 V
Phase cable, 63 W phase cable, 70 control device, 100 motor, 101 central axis, 510-517, 520-527, 530-537 coil, C1, C2, C3 curved surface, L1, L2 line, P1 plane part, R1, R2, R3 curvature circle, S stress relaxation curved surface, UN1, UN2, VN1, VN2, WN1, WN2 neutral point, U1, U2, V1, V2, W1, W2 terminals.

Claims (4)

A rotating shaft having a cylindrical outer peripheral surface and provided with a keyway;
A rotor core provided with a through-hole through which the rotary shaft passes, and including a key portion that protrudes from an inner peripheral surface of the through-hole and is fitted into the key groove,
An inner peripheral surface of the through hole is formed in a cylindrical shape centering on a central axis of the rotary shaft, and is disposed on both sides of the key portion and a cylindrical inner peripheral surface along the outer peripheral surface of the rotary shaft. Including a recessed portion inner peripheral surface constituting a recessed portion recessed in a direction away from the outer peripheral surface of
A cross section perpendicular to the central axis of the rotary shaft of the inner peripheral surface of the recess has a first radius of curvature and a first arc portion whose tangential direction is continuous with a side surface of the key portion, and a second radius of curvature. And a second arc portion continuous in a tangential direction of the first arc portion,
The second radius of curvature is larger than the first radius of curvature, and the line connecting the center of the second radius of curvature and the central axis of the rotary shaft is the center of the first radius of curvature and the rotary shaft. The rotor is located at a position away from the side surface of the key portion with respect to a line connecting the central axis of the key portion.   The rotor according to claim 1, wherein the second radius of curvature is not less than 1.5 times and not more than 2.5 times the first radius of curvature.   A cross section perpendicular to the central axis of the rotating shaft of the inner peripheral surface of the recess is continuous to a tangential direction of the second arc portion and a tangential direction of the linear portion and the cylindrical inner peripheral surface. The rotor according to claim 1, further comprising a third arc portion.   A rotating electrical machine comprising the rotor according to any one of claims 1 to 3.

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