JP5482544B2 - Rotating electric machine - Google Patents

Description

  The present invention generally relates to a rotating electrical machine, and more particularly to a rotating electrical machine including a rotor core in which a permanent magnet is embedded.

  Regarding a conventional rotating electric machine, for example, Japanese Patent Application Laid-Open No. 2009-124899 discloses a PM (Permanent Magnet) synchronous motor for the purpose of realizing an increase in torque with a small amount of magnet (Patent Document 1). ). The PM synchronous motor disclosed in Patent Document 1 includes a rotor composed of a soft magnetic rotor core, a front permanent magnet, a rear permanent magnet, and a soft magnetic segment. The front permanent magnet and the rear permanent magnet are embedded in the rotor core.

  Japanese Patent Laid-Open No. 2005-223955 aims to increase the durability of the rotor core by relaxing the stress concentration in the region sandwiched between the permanent magnet support holes formed at predetermined intervals along the outer peripheral surface of the rotor core. A rotor of a rotating electric machine is disclosed (Patent Document 2). In the rotor of the rotating electrical machine disclosed in Patent Document 2, 16 permanent magnet support holes are formed at equal intervals along the outer peripheral surface of the rotor core. A permanent magnet having a hexagonal cross-sectional shape is inserted into each permanent magnet support hole. A triangular through hole is formed in a region of the rotor core sandwiched between the inclined surfaces of two adjacent permanent magnets and the outer peripheral surface of the rotor core.

  Japanese Patent Laying-Open No. 2008-167549 discloses a rotor of a rotating electrical machine that aims to increase the durability of the rotor core by reducing stress concentration at the radially outer corner of the permanent magnet support hole of the rotor core. (Patent Document 3). In the rotating electrical machine disclosed in Patent Document 3, a plurality of permanent magnet support holes are formed at equal intervals along the outer peripheral surface of the rotor core. A V-shaped notch is formed between the outer peripheral surface of the rotor core and the adjacent permanent magnet support hole.

  Japanese Patent Application Laid-Open No. 2007-89291 discloses a permanent magnet type rotating electrical machine intended to suppress deformation of the rotor core (Patent Document 4). In the permanent magnet type rotating electrical machine disclosed in Patent Document 4, a plurality of openings are formed in the rotor core. The plurality of openings are formed at the outer peripheral end of the rotor core so that a pair of adjacent openings is V-shaped so as to protrude radially inward. Permanent magnets are respectively disposed in the pair of openings, and these permanent magnets constitute a magnetic pole as a pair. The rotor core is formed with a slit having a through-hole shape between the magnetic poles and approximately at the center of the magnet.

  Japanese Patent Laid-Open No. 2007-97387 discloses a permanent magnet embedded type rotating electrical machine that aims to reduce vibration and noise generated by electromagnetic force while maintaining a small size and high output. (Patent Document 5). In the rotating electrical machine disclosed in Patent Document 5, a plurality of permanent magnets are embedded in a rotor core.

JP 2009-124899 A Japanese Patent Laid-Open No. 2005-22395 JP 2008-167549 A JP 2007-89291 A JP 2007-97387 A

  As disclosed in the above-described patent documents, an IPM (Interior Permanent Magnet) motor in which a permanent magnet is embedded in a rotor core is known. In the rotor core used in the IPM motor, an outer peripheral bridge extending in a rib shape is formed between the outer peripheral surface of the rotor core and the magnet insertion hole due to the structure in which the magnet insertion hole for inserting the permanent magnet is formed. In an IPM motor having such a structure, when the shaft is fitted to the inner periphery of the rotor core, stress concentration occurs in the outer periphery bridge, which may reduce the durability of the rotor core.

  SUMMARY OF THE INVENTION An object of the present invention is to solve the above-described problems and to provide a rotating electrical machine that can improve the durability of a rotor core.

  A rotating electrical machine according to the present invention includes a rotor core having a shaft fitted on an inner periphery thereof, and a plurality of magnets provided on the rotor core. The rotor core has an outer peripheral surface. The rotor core is provided with a plurality of insertion holes into which magnets are inserted and spaced apart in the circumferential direction around the rotation axis. A magnet is hold | maintained in an insertion hole so that the 1st space and the 2nd space arrange | positioned in the outer peripheral side rather than the 1st space may be provided in the both ends of a magnet. The plurality of insertion holes include a first insertion hole and a second insertion hole provided adjacent to the first insertion hole. When the rotor core is cut along a plane perpendicular to the rotation axis, the cross-sectional shapes of the first insertion hole and the second insertion hole are V-shaped so as to be convex on the outer peripheral side and concave on the inner peripheral side. The rotor core is further formed with a slit provided at a central position between the first insertion hole and the second insertion hole. When the rotor core is cut along a plane perpendicular to the rotation axis, the cross-sectional shape of the slit has a slit main body extending from the outer peripheral surface in the radial direction centering on the rotation axis of the rotor core.

  According to the rotating electrical machine thus configured, the slit having the slit main body extending in the radial direction from the outer peripheral surface of the rotor core is located at the center position between the first insertion hole and the second insertion hole having a V shape. It is formed. As a result, the distortion of the rotor core toward the radially outer side generated when the shaft is fitted to the inner periphery of the rotor core is absorbed by the slit main body portion, and the outer peripheral surface of the rotor core, the first insertion hole, and the second insertion hole It is possible to reduce the stress concentration generated between the two. Thereby, durability of a rotor core can be improved.

  Preferably, when the rotor core is cut along a plane perpendicular to the rotation axis thereof, the cross-sectional shape of the slit is provided at the end of the slit body, and the circumferential direction around the rotation axis of the rotor core is greater than the slit body. Furthermore, it has a slit end portion having a large width. According to the rotating electric machine configured as described above, the stress concentration generated at the end of the slit main body due to the absorption of strain by the slit main body can be reduced by the slit end.

  Preferably, the slit end portion is disposed on the outer peripheral side of the inner peripheral end of the first space in the radial direction centered on the rotation axis of the rotor core.

  According to the rotating electrical machine configured as described above, the uniformity of the shape of the rotor core in the circumferential direction is greater than that in the case where the slit end is disposed on the inner peripheral side with respect to the inner peripheral end of the first space. This can reduce the concern that excessive stress concentration will occur at the slit end. Thereby, stress concentration generated at the slit end can be sufficiently relaxed while reducing the sectional area of the slit end. As a result, it is possible to prevent the slit end from interfering with the magnetic flux flow inside the rotor core or reducing the strength of the rotor core.

  Preferably, the slit end has a circular cross-sectional shape. According to the rotating electric machine configured as described above, it is possible to suppress a local increase in stress concentration generated at the slit end.

  Preferably, the plurality of insertion holes further include a third insertion hole provided on the opposite side of the second insertion hole with the first insertion hole interposed therebetween. In the circumferential direction around the rotation axis of the rotor core, the first insertion hole and the second insertion hole are arranged with a first interval, and the first insertion hole and the third insertion hole are more than the first interval. Are also arranged with a small second spacing.

  According to the rotating electrical machine configured as described above, the first insertion hole and the second insertion hole have a larger distance than the first insertion hole and the third insertion hole, and therefore the rotor core. When the shaft is fitted to the inner periphery of the rotor core, the distortion of the rotor core toward the radially outer side increases. For this reason, by providing a slit between the first insertion hole and the second insertion hole, stress concentration generated between the outer peripheral surface of the rotor core and the first insertion hole and the second insertion hole can be more effectively reduced. can do.

  Preferably, the plurality of insertion holes further include a third insertion hole provided on the opposite side of the second insertion hole with the first insertion hole interposed therebetween. When the rotor core is cut along a plane perpendicular to the rotation axis thereof, the first insertion hole and the third insertion hole have a V-shaped cross section that is concave on the outer peripheral side and convex on the inner peripheral side.

  According to the rotating electrical machine configured as described above, the first insertion hole and the second insertion hole have a V-shape in which the cross-sectional shapes are convex on the outer peripheral side and concave on the inner peripheral side. Between the first insertion hole and the second insertion hole, the distance of the second space between the adjacent insertion holes is smaller than that between the first insertion hole and the third insertion hole. For this reason, by providing a slit between the first insertion hole and the second insertion hole, stress concentration generated between the outer peripheral surface of the rotor core and the second space of the first insertion hole and the second insertion hole is reduced. It can be mitigated more effectively.

  Preferably, the slit body is formed by applying a shearing force along the rotation axis direction to the rotor core. According to the rotating electric machine configured as described above, it is possible to suppress the slit main body from interfering with the magnetic flux flow inside the rotor core by suppressing the slit width of the slit main body as small as possible.

  Preferably, the first space has a larger cross-sectional area than the second space when the rotor core is cut along a plane perpendicular to the rotation axis thereof. According to the rotating electrical machine configured as described above, the first space having a larger cross-sectional area than the second space and the second space disposed on the outer peripheral side of the first space are provided at both ends of the magnet. In the rotating electrical machine including the rotor core, stress concentration generated between the outer peripheral surface of the rotor core and the second space can be reduced.

  As described above, according to the present invention, a rotating electrical machine capable of improving the durability of the rotor core can be provided.

It is sectional drawing which represents the drive unit for vehicles typically. It is sectional drawing which shows the rotor core along the II-II line | wire in FIG. It is sectional drawing which expands and shows the range enclosed with the dashed-two dotted line III in FIG. In a motor generator for comparison, it is a sectional view showing a state of deformation of a rotor core when a rotor shaft is fitted. FIG. 2 is a cross-sectional view showing a state of deformation of a rotor core when a rotor shaft is fitted in the motor generator in FIG. 1. It is sectional drawing which shows the modification of the rotor core in FIG. It is a figure which shows the manufacturing process which forms a slit main-body part in the rotor core in FIG. FIG. 7 is a cross-sectional view showing a first modification of the motor generator in FIG. 1. FIG. 10 is a cross-sectional view showing a second modification of the motor generator in FIG. 1.

  Embodiments of the present invention will be described with reference to the drawings. In the drawings referred to below, the same or corresponding members are denoted by the same reference numerals.

(Embodiment 1)
FIG. 1 is a cross-sectional view schematically showing a vehicle drive unit. The vehicle drive unit shown in the figure is provided in a hybrid vehicle using an internal combustion engine such as a gasoline engine or a diesel engine and a motor that receives power supply from a chargeable / dischargeable secondary battery (battery) as a power source. .

  Referring to FIG. 1, the vehicle drive unit has a motor generator 10. The motor generator 10 is a rotating electrical machine that functions as an electric motor or a generator in accordance with the traveling state of the hybrid vehicle. First, a basic structure of motor generator 10 in the present embodiment and a vehicle drive unit on which motor generator 10 is mounted will be described.

  The motor generator 10 has a rotor shaft 41, a rotor core 21, and a stator core 31 as its components. The rotor core 21 is integrated with the rotor shaft 41 and rotates around the central axis 101 which is a virtual axis. That is, the central axis 101 is the rotation axis of the rotor core 21. A stator core 31 is disposed on the outer periphery of the rotor core 21.

  The rotor shaft 41 extends in the axial direction of the central axis 101. The rotor shaft 41 has a cylindrical shape in which a hollow portion 42 is formed. The rotor shaft 41 is rotatably supported with respect to a motor case as a case body (not shown) via a bearing 46 and a bearing 47 provided at a distance in the axial direction of the central shaft 101. The rotor shaft 41 is connected to a speed reduction mechanism 15 that includes a plurality of gears.

  An oil pump 48 is provided at one end of the rotor shaft 41. The oil pump 48 is a gear-type oil pump that discharges oil as the rotor shaft 41 rotates. The oil discharged from the oil pump 48 is introduced into the hollow part 42 in order to cool or lubricate each part of the motor generator 10. The rotor shaft 41 is formed with an oil supply hole 43 for supplying the oil introduced into the hollow portion 42 toward the rotor core 21 and the stator core 31.

  The means for supplying oil to the hollow portion 42 is not limited to the pump as shown in the figure. For example, the oil swept up by the gear is collected in a catch tank, and the oil is guided to the hollow portion 42 by gravity. It may be a mechanism.

  The rotor core 21 has a shape extending in a cylindrical shape in the axial direction of the central shaft 101. The rotor core 21 is composed of a plurality of electromagnetic steel plates 22 stacked in the axial direction of the central shaft 101. The electromagnetic steel plate 22 has a flat disk shape extending in a plane orthogonal to the central axis 101.

  The rotor core 21 has an end surface 21a facing one end side in the direction in which the central axis 101 extends and an end surface 21b facing the other end side in the direction in which the central axis 101 extends. The end surface 21a and the end surface 21b each extend in a plane orthogonal to the central axis 101. The rotor core 21 further has an outer peripheral surface 21c. The outer peripheral surface 21 c extends on the outer periphery about the central axis 101. The stator core 31 is disposed on the outer periphery of the rotor core 21 with a clearance from the outer peripheral surface 21c.

  A hollow hole 28 is formed in the rotor core 21. The hollow hole 28 is formed so as to penetrate the rotor core 21 in the axial direction of the central shaft 101 and open to the end surface 21a and the end surface 21b. When the rotor core 21 is cut along a plane perpendicular to the central axis 101, the hollow hole 28 has a circular cross-sectional shape centered on the central axis 101. The rotor shaft 41 is fitted into the inner periphery of the rotor core 21, that is, the hollow hole 28. The rotor shaft 41 and the rotor core 21 are fitted to each other by an interference fit relationship. The rotor shaft 41 is fitted on the inner periphery of the rotor core 21 by shrink fitting.

  The motor generator 10 further has a permanent magnet 26 as its component. The permanent magnet 26 is embedded in the rotor core 21. More specifically, a magnet insertion hole 27 is formed in the rotor core 21. The magnet insertion hole 27 is formed so as to penetrate the rotor core 21 in the axial direction of the central shaft 101 and open to the end surface 21a and the end surface 21b. The permanent magnet 26 is inserted into the magnet insertion hole 27.

  The stator core 31 has a shape extending in a cylindrical shape in the axial direction of the central shaft 101. The stator core 31 is composed of a plurality of electromagnetic steel plates 32 stacked in the axial direction of the central shaft 101. The stator core 31 has an end surface 31a facing one end in the direction in which the central axis 101 extends, and an end surface 31b facing the other end in the direction in which the central axis 101 extends.

  The motor generator 10 further has a coil 36 as its component. A coil 36 is wound around the stator core 31. The coil 36 is made of, for example, a copper wire with an insulating coating. The coil 36 has a coil end portion 36p and a coil end portion 36q. The coil end portion 36p and the coil end portion 36q are formed so as to protrude in the axial direction of the central shaft 101 from the end surface 31a and the end surface 31b, respectively. The coil end portions 36p and 36q are provided on the end surfaces 31a and 31b so as to circulate around the central axis 101 in an annular shape.

  The coil 36 includes a U-phase, V-phase, and W-phase coil. Terminals corresponding to these phase coils are connected to the terminal block 12. The terminal block 12 is electrically connected to the battery 14 via the inverter 13. The inverter 13 converts the direct current from the battery 14 into an alternating current for driving the motor, and converts the alternating current generated by the regenerative brake into a direct current for charging the battery 14.

  In the present embodiment, rotor core 21, rotor shaft 41 and permanent magnet 26 constitute a rotor of motor generator 10, and stator core 31 and coil 36 constitute a stator of motor generator 10.

  The power output from the motor generator 10 is transmitted from the speed reduction mechanism 15 to the drive shaft receiving portion 17 via the differential mechanism 16. The power transmitted to the drive shaft receiving portion 17 is transmitted as a rotational force to a wheel (not shown) via the drive shaft.

  On the other hand, during regenerative braking of the hybrid vehicle, the wheels are rotated by the inertial force of the vehicle body. The motor generator 10 is driven through the drive shaft receiving portion 17, the differential mechanism 16 and the speed reduction mechanism 15 by the rotational force from the wheels. At this time, the motor generator 10 operates as a generator. The electric power generated by the motor generator 10 is stored in the battery 14 via the inverter 13.

  FIG. 2 is a cross-sectional view showing the rotor core along the line II-II in FIG. 3 is an enlarged cross-sectional view of a range surrounded by a two-dot chain line III in FIG. When the rotor core 21 is cut along an arbitrary plane orthogonal to the central axis 101, the same shape as the cross-sectional shape shown in FIGS. 2 and 3 is obtained.

  Referring to FIGS. 2 and 3, a more detailed structure of motor generator 10 will be described. A plurality of magnet insertion holes 27 are formed in rotor core 21. The plurality of magnet insertion holes 27 are provided at intervals in the circumferential direction around the central axis 101. A permanent magnet 26 is inserted into each of the plurality of magnet insertion holes 27. The permanent magnet 26 is held inside the magnet insertion hole 27 by a resin mold part 61 (see FIG. 3) interposed between the surface of the permanent magnet 26 and the inner wall of the magnet insertion hole 27.

  When the rotor core 21 is cut along a plane orthogonal to the central axis 101, the sectional shape of the magnet insertion hole 27 has an outer peripheral portion 53, an intermediate portion 54, and an inner peripheral portion 55. The outer peripheral part 53, the intermediate part 54, and the inner peripheral part 55 are arranged side by side in the order given from the outer peripheral side to the inner peripheral side.

  The outer peripheral part 53 is provided adjacent to the outer peripheral surface 21c. The outer peripheral portion 53 has a substantially triangular cross-sectional shape. The intermediate portion 54 has a shape corresponding to the shape of the permanent magnet 26, in this embodiment, a rectangular cross-sectional shape. The permanent magnet 26 is positioned at the intermediate portion 54. The inner peripheral portion 55 is formed so as to expand from the intermediate portion 54 toward the inner side in the radial direction around the central axis 101. The inner peripheral portion 55 has a larger cross-sectional area than the outer peripheral portion 53. The intermediate portion 54 extends obliquely with respect to the radial direction about the central axis 101 between the outer peripheral portion 53 and the inner peripheral portion 55.

  In FIG. 3, among the plurality of magnet insertion holes 27 formed in the rotor core 21, a magnet insertion hole 27 s as a third insertion hole, a magnet insertion hole 27 t as a first insertion hole, and a second insertion hole The magnet insertion hole 27u and the magnet insertion hole 27v are shown. The magnet insertion hole 27s, the magnet insertion hole 27t, the magnet insertion hole 27u, and the magnet insertion hole 27v are provided side by side in the circumferential direction around the central axis 101 in the order listed.

  When attention is paid to the magnet insertion hole 27s and the magnet insertion hole 27t shown in FIG. 3, the magnet insertion hole 27s and the magnet insertion hole 27t have a symmetrical shape, and the center positions of the magnet insertion hole 27s and the magnet insertion hole 27t. Assuming a virtual line 103 passing through the central axis 101, when the magnet insertion hole 27s is reversed with respect to the straight line 103, the magnet insertion hole 27s and the magnet insertion hole 27t are completely overlapped. The magnet insertion hole 27s and the magnet insertion hole 27t are formed in a V shape that is concave on the outer peripheral side and convex on the inner peripheral side. The magnet insertion hole 27 s and the magnet insertion hole 27 t are formed so as to be closest to each other in the inner peripheral portion 55 in the circumferential direction around the central axis 101, and away from each other as they move to the intermediate portion 54 and the outer peripheral portion 53.

  Next, paying attention to the magnet insertion hole 27u and the magnet insertion hole 27v shown in FIG. 3, the magnet insertion hole 27u and the magnet insertion hole 27v have the same shape as the magnet insertion hole 27s and the magnet insertion hole 27t, respectively. When the magnet insertion hole 27u and the magnet insertion hole 27v are rotated by a predetermined angle around the central axis 101, the magnet insertion hole 27u and the magnet insertion hole 27s are completely overlapped, and the magnet insertion hole 27v and the magnet insertion hole 27t completely overlaps. Further, when attention is paid to the magnet insertion hole 27t and the magnet insertion hole 27u shown in FIG. 3, the magnet insertion hole 27t and the magnet insertion hole 27u have a V-shape that is convex on the outer peripheral side and concave on the inner peripheral side. It is formed as follows. The magnet insertion hole 27t and the magnet insertion hole 27u are formed so as to be closest to each other in the outer peripheral portion 53 in the circumferential direction around the central axis 101, and away from each other toward the inner peripheral portion 55 in the intermediate portion 54.

  In the present embodiment, in the circumferential direction around the central axis 101, the magnet insertion hole 27s (magnet insertion hole 27u) and the magnet insertion hole 27t (magnet insertion hole 27v) are provided with a relatively small interval B1. The magnet insertion hole 27t and the magnet insertion hole 27u are arranged with a relatively large distance B2.

  2, the two magnet insertion holes 27 corresponding to the magnet insertion hole 27s and the magnet insertion hole 27t are provided side by side in the circumferential direction around the central shaft 101. ing.

  In the range shown in FIG. 3, permanent magnet 26A, permanent magnet 26B, permanent magnet 26C and permanent magnet 26D are inserted into magnet insertion hole 27s, magnet insertion hole 27t, magnet insertion hole 27u and magnet insertion hole 27v, respectively. ing.

  The permanent magnet 26A and the permanent magnet 26B are paired to form one magnetic pole (N pole in the present embodiment), and the permanent magnet 26C and the permanent magnet 26D are paired to form the permanent magnet 26A and the permanent magnet. One magnetic pole (in this embodiment, S pole) different from 26B is formed. In the entire rotor core 21 shown in FIG. 2, the plurality of permanent magnets 26 are respectively inserted into the plurality of magnet insertion holes 27 so that the N poles and the S poles are alternately arranged in the circumferential direction around the central axis 101. Has been inserted.

  The number of permanent magnets 26 shown in FIG. 2 is an example, and is appropriately selected depending on the performance required for the motor generator 10.

  The center positions of the N and S poles arranged in the circumferential direction around the center axis 101 (in the range shown in FIG. 3, the center position between the permanent magnet 26A and the permanent magnet 26B, and the permanent magnet 26C and the permanent magnet). The axis along the imaginary line 103 passing through the center axis 101) and the center axis 101 is referred to as a d-axis. A center position between the north and south poles adjacent in the circumferential direction about the center axis 101 (in the range shown in FIG. 3, the center position between the permanent magnet 26B and the permanent magnet 26C), The axis along the imaginary line 102 passing through is called the q axis.

  In a state where the permanent magnet 26 is held in the magnet insertion hole 27, an outer diameter side flux barrier 51 and an inner diameter side flux barrier 52 are formed at both ends of the permanent magnet 26, respectively.

  The outer diameter side flux barrier 51 is formed by the outer peripheral portion 53. The outer diameter side flux barrier 51 is formed by a gap between the permanent magnet 26 and the inner wall of the outer peripheral portion 53. The inner diameter side flux barrier 52 is formed by the inner peripheral portion 55. The inner diameter side flux barrier 52 is formed by a gap between the permanent magnet 26 and the inner wall of the inner peripheral portion 55. The outer diameter side flux barrier 51 is provided on the outer peripheral side with respect to the inner diameter side flux barrier 52. When the rotor core 21 is cut along a plane orthogonal to the central axis 101, the inner diameter side flux barrier 52 has a larger cross-sectional area than the outer diameter side flux barrier 51.

  The plurality of inner diameter side flux barriers 52 are formed so that the inner peripheral ends of the inner diameter side flux barriers 52 are aligned on the circumference of a virtual circle 104 (see FIG. 3) drawn around the central axis 101. Has been. The rotor core 21 between the virtual circle 104 and the hollow hole 28 is not formed with a hole or a recess.

  An outer peripheral bridge 81 is formed between the outer peripheral surface 21 c of the rotor core 21 and the outer diameter side flux barrier 51. The outer peripheral bridge 81 is formed adjacent to the outer peripheral surface 21c. The outer peripheral bridge 81 is formed to extend in a rib shape along the circumferential direction centering on the central axis 101. The outer peripheral bridge 81 is formed to have a thin wall in the radial direction around the central axis 101. In the range shown in FIG. 3, the outer peripheral bridge 81 formed by the magnet insertion hole 27 t and the outer peripheral bridge 81 formed by the magnet insertion hole 27 u face each other across the q axis along the virtual line 102.

  A slit 76 is formed in the rotor core 21. The slit 76 is provided between the magnet insertion holes 27 adjacent to each other. The slit 76 is provided between the magnet insertion holes 27 arranged in a V shape so as to be convex on the outer peripheral side and concave on the inner peripheral side. The slit 76 is inserted with a magnet insertion hole 27 into which the permanent magnet 26 constituting one magnetic pole of the N pole and S pole is inserted, and the permanent magnet 26 constituting the other magnetic pole among the N pole and S pole. It is provided between the magnet insertion hole 27. In the range shown in FIG. 3, the slit 76 is between the magnet insertion hole 27t into which the permanent magnet 26B constituting the N pole is inserted and the magnet insertion hole 27u into which the permanent magnet 26C constituting the S pole is inserted. Is provided. The slit 76 is provided at the center position between the magnet insertion hole 27t and the magnet insertion hole 27u. The slit 76 is provided so as to overlap the q axis along the imaginary line 102. A plurality of slits 76 are provided at equal intervals in the circumferential direction around the central axis 101.

  Referring to FIG. 3, slit 76 is formed so as to penetrate rotor core 21 in the axial direction of central axis 101 and open to end surface 21 a and end surface 21 b. When the rotor core 21 is cut along a plane orthogonal to the central axis 101, the cross-sectional shape of the slit 76 includes a slit main body 71 and a slit end 72.

  The slit main body 71 extends linearly from the outer peripheral surface 21c toward the inside in the radial direction with the central axis 101 as the center. The slit main body 71 has one end 71p that opens to the outer peripheral surface 21c and the other end 71q that is disposed at the tip that extends linearly from the one end 71p. The slit main body 71 is formed between the one end 71p and the other end 71q so as to overlap the q-axis along the virtual line 102. In the circumferential direction centering on the central axis 101, the slit main body 71 has a width B3. The slit main body 71 has a constant width B3 between one end 71p and the other end 71q. The width B3 is a value of 10 μm or less, for example.

  The slit end 72 is provided at the other end 71 q of the slit main body 71. The slit end 72 is connected to the other end 71q. In the circumferential direction around the central axis 101, the slit end 72 has a width B4 that is larger than the width B3. The slit end 72 has a circular cross-sectional shape. The slit end 72 has a circular cross-sectional shape centered on a point on the q axis along the virtual line 102.

  In addition, although the slit end part 72 which has a perfect circle cross-sectional shape is shown by the rotor core 21 in FIG. 3, it is not restricted to this, For example, the slit end part 72 is circular other than perfect circles, such as an ellipse. It may have a cross section.

  In the present embodiment, the slit end 72 is disposed on the outer peripheral side of the inner peripheral end of the inner diameter side flux barrier 52 in the radial direction centering on the central axis 101. That is, the slit end 72 is disposed on the outer peripheral side with respect to the virtual axis 104 drawn with the central axis 101 and the center in FIG. The slit end portion 72 is disposed at a position overlapping the inner diameter side flux barrier 52 when rotated in the circumferential direction around the central axis 101.

  Next, functions and effects achieved by the motor generator 10 of FIG. 1 will be described. FIG. 4 is a cross-sectional view showing a state of deformation of the rotor core when the rotor shaft is fitted in the motor generator for comparison. FIG. 5 is a cross-sectional view showing a state of deformation of the rotor core when the rotor shaft is fitted in the motor generator in FIG.

  In the following, the description will be made while paying attention to the gap between the magnet insertion hole 27t and the magnet insertion hole 27u shown in FIGS. Is done.

  Referring to FIG. 4, in the motor generator in this comparative example, slit 76 shown in FIGS. 2 and 3 is not formed in rotor core 21.

  When the rotor shaft 41 is fitted to the rotor core 21 by shrink fitting, a radially outward force about the central axis 101 acts on the rotor core 21. As a result of the force passing between the magnet insertion hole 27t and the magnet insertion hole 27u and reaching the outer peripheral side, the outer peripheral surface 21c of the rotor core 21 tends to be deformed radially outward as indicated by a dotted line 21c '. At this time, the outer peripheral bridge 81 between the outer peripheral surface 21 c and the outer diameter side flux barrier 51 has a thin shape in the radial direction centering on the central axis 101, and thus stress concentration occurs in the outer peripheral bridge 81. .

  Referring to FIG. 5, on the other hand, in motor generator 10 in the present embodiment, slit main body 71 is formed between magnet insertion hole 27 t and magnet insertion hole 27 u of rotor core 21. With such a configuration, the rotor core 21 is slightly distorted on both sides starting from the slit main body 71 as a radial outward force about the central axis 101 acts on the rotor core 21. As a result, the deformation of the outer peripheral surface 21c of the rotor core 21 toward the outer side in the radial direction is greatly reduced as indicated by the dotted line 21c ′, and the stress concentration generated in the outer peripheral bridge 81 can be reduced.

  On the other hand, when the rotor core 21 is distorted on both sides starting from the slit main body 71, stress concentration occurs at the other end 71q of the slit main body 71. In contrast, in motor generator 10 according to the present embodiment, slit end 72 having a larger width than slit main body 71 is provided at the other end 71q of slit main body 71. With such a configuration, the force generated when the rotor core 21 is distorted with the slit main body 71 as a starting point can be widely dispersed and received at the peripheral edge of the slit end 72. Thereby, the stress concentration produced at the other end 71q of the slit main body 71 can be relaxed. At this time, since the slit end portion 72 has a circular cross-sectional shape, local stress concentration is caused at the peripheral edge portion of the slit end portion 72 as compared with the case where the slit end portion 72 has a cross-sectional shape including a corner portion. Can be avoided.

  With respect to the form of the rotor core 21 shown in FIG. 3, a slit 76 may be formed on the d-axis between the magnet insertion hole 27s and the magnet insertion hole 27t and between the magnet insertion hole 27u and the magnet insertion hole 27v. is assumed.

  However, since the gap between the magnet insertion hole 27t and the magnet insertion hole 27u is larger than that between the magnet insertion hole 27s and the magnet insertion hole 27t or between the magnet insertion hole 27u and the magnet insertion hole 27v, the rotor core When the rotor shaft 41 is fitted to the inner periphery of the rotor 21, the distortion of the rotor core 21 toward the radially outer side increases. In the rotor core 21 shown in FIG. 3, the slit 76 is provided between the magnet insertion hole 27 t and the magnet insertion hole 27 u where the distortion of the rotor core 21 is increased. Remarkably can be obtained. In the form of the rotor core 21 shown in FIG. 3, the distance between the outer peripheral flux barrier 51 of the magnet insertion hole 27t and the outer peripheral flux barrier 51 of the magnet insertion hole 27u is shortened, and a slit 76 is provided at that position. For this reason, the effect of relieving stress concentration generated in the outer peripheral bridge 81 can be remarkably obtained.

  FIG. 6 is a cross-sectional view showing a modification of the rotor core in FIG. With reference to FIG. 6, in this modification, the cross-sectional shape of the rotor core 21 has a slit end 73 instead of the slit end 72 in FIG. The slit end portion 73 is disposed on the inner peripheral side with respect to the inner peripheral end of the inner diameter side flux barrier 52 in the radial direction about the central axis 101. That is, the slit end portion 73 is disposed on the inner peripheral side with respect to the virtual axis 104 drawn with the central axis 101 and the center in FIG.

  Even in the rotor core 21 having such a configuration, the stress concentration generated in the outer peripheral bridge 81 can be alleviated when the rotor core 21 is slightly distorted on both sides starting from the slit main body 71. In addition, the stress generated at the other end 71q of the slit body 71 is concentrated by receiving the force generated when the rotor core 21 is distorted starting from the slit body 71 at the peripheral edge of the slit end 73. Can be relaxed.

  On the other hand, in the present modification, the uniformity of the shape of the rotor core 21 is impaired in the circumferential direction around the central axis 101 by the slit end 73 disposed on the inner peripheral side with respect to the inner peripheral end of the inner diameter side flux barrier 52. It is. For this reason, the force that acts on the rotor core 21 due to the fitting of the rotor shaft 41 is concentrated on the slit end portion 73, and the stress concentration occurs at the slit end portion 73.

  In order to relieve the stress concentration thus generated, it is necessary to increase the cross-sectional area of the slit end portion 73, but in this case, there is a concern that the strength of the rotor core 21 is reduced by the slit end portion 73. In addition, since the magnet insertion hole 27t and the magnet insertion hole 27u are between the magnetic poles of the N pole and the S pole, a magnetic flux flows as shown by an arrow 110 as the motor generator 10 is operated. If the cross-sectional area of the slit end 73 is large, there is a concern that the magnetic flux flow in the rotor core 21 is largely hindered by the slit end 73.

  Referring to FIG. 5, in contrast, when the slit end portion 72 is arranged on the outer peripheral side of the inner peripheral end of the inner diameter side flux barrier 52, the inner diameter side flux barrier is disposed on the same circumference of the slit end portion 72. 52 exists, the concern that the force acting on the rotor core 21 due to the fitting of the rotor shaft 41 is concentrated on the slit end portion 72 is reduced. Further, since the slit end portion 72 is arranged on the outer peripheral side as compared with the modification shown in FIG. 6, the force applied to the slit end portion 72 is also greatly dispersed in the circumferential direction. For this reason, the cross-sectional area of the slit end portion 72 can be reduced, the strength of the rotor core 21 can be ensured, and the magnetic characteristics of the motor generator 10 can be maintained.

  Subsequently, a characteristic manufacturing process applied to the motor generator 10 in FIG. 1 will be described.

  7 is a view showing a manufacturing process for forming the slit main body portion in the rotor core in FIG. 3, FIG. 7 (A) is a plan view, and FIG. 7 (B) is a cross-sectional view of FIG. It is sectional drawing along the B line. Referring to FIG. 7, in the present embodiment, slit main body 71 is formed in rotor core 21 using mold device 86 having upper mold 87 and lower mold 88.

  More specifically, first, the slit end portion 72 is formed on the electromagnetic steel plate 22 constituting the rotor core 21 using an appropriate processing machine such as a press device or a drill. Next, the electromagnetic steel plate 22 is set in the mold device 86. At this time, the upper mold 87 is disposed on the upper surface of the electromagnetic steel sheet 22, and the lower mold 88 is disposed on the lower surface of the electromagnetic steel sheet 22 at a position shifted from the upper mold 87. The end portion 87m of the upper mold 87 and the end portion 88m of the lower mold 88 are overlapped on the upper and lower surfaces of the electromagnetic steel plate 22, and the overlapping end portion 87m and end portion 88m start from the slit end portion 72 in the radial direction. The upper mold 87 and the lower mold 88 are arranged so as to extend linearly outward. The slit main body 71 is formed in the electromagnetic steel sheet 22 by moving the upper mold 87 and the lower mold 88 in the thickness direction of the electromagnetic steel sheet 22.

  According to such a manufacturing process, the slit main body 71 is formed by applying a shearing force in the thickness direction to the electromagnetic steel plate 22 constituting the rotor core 21. In this case, it becomes possible to suppress the slit width of the slit main body 71 as small as possible, and the magnetic flux flow in the rotor core 21 can be prevented from being obstructed by the slit main body 71.

  When the structure of the motor generator 10 according to the first embodiment of the present invention described above is described together, the motor generator 10 as a rotating electrical machine according to the present embodiment has a rotor shaft 41 as a shaft fitted on the inner periphery thereof. And a permanent magnet 26 as a plurality of magnets provided on the rotor core 21. The rotor core 21 has an outer peripheral surface 21c. The rotor core 21 is provided with a plurality of magnet insertion holes 27 serving as a plurality of insertion holes into which the permanent magnets 26 are inserted. The permanent magnet 26 has an inner diameter side flux barrier 52 as a first space and an outer diameter side flux barrier 51 as a second space arranged on the outer peripheral side of the inner diameter side flux barrier 52 at both ends of the permanent magnet 26. It is held in the magnet insertion hole 27 so as to be provided.

  The plurality of magnet insertion holes 27 include a magnet insertion hole 27t as a first insertion hole and a magnet insertion hole 27u as a second insertion hole provided adjacent to the magnet insertion hole 27t. When the rotor core 21 is cut along a plane orthogonal to the central axis 101, the cross-sectional shapes of the magnet insertion hole 27t and the magnet insertion hole 27u are V-shaped so as to be convex on the outer peripheral side and concave on the inner peripheral side. The rotor core 21 is further formed with a slit 76 provided at the center position between the magnet insertion hole 27t and the magnet insertion hole 27u. When the rotor core 21 is cut along a plane perpendicular to the central axis 101, the cross-sectional shape of the slit 76 has a slit main body 71 that extends from the outer peripheral surface 21c in the radial direction about the central axis 101.

  According to motor generator 10 configured in this way in the first embodiment of the present invention, the durability of rotor core 21 can be improved by reducing the stress concentration generated in rotor core 21.

  In the present embodiment, the case where the rotating electrical machine according to the present invention is applied to a motor generator mounted on a hybrid vehicle has been described. However, the present invention is not limited to this, and a motor mounted on an electric vehicle or a general industrial application is described. You may apply to a motor.

(Embodiment 2)
In the present embodiment, various modifications of motor generator 10 in the first embodiment will be described. The motor generator described in the present embodiment basically has the same structure as motor generator 10 in the first embodiment. Hereinafter, the description of the overlapping structure will not be repeated.

  FIG. 8 is a cross-sectional view showing a first modification of the motor generator in FIG. Referring to FIG. 8, in this modification, the outer diameter side flux barrier 51 and the inner diameter side flux barrier 52 are filled with a resin portion 89. Even in such a configuration, since the rib-shaped outer peripheral bridge 81 is formed between the outer peripheral surface 21c and the outer diameter side flux barrier 51, the formation of the slit 76 is effective.

  FIG. 9 is a cross-sectional view showing a second modification of the motor generator in FIG. Referring to FIG. 9, in this modification, the magnet insertion hole 27s (magnet insertion hole 27u) and the magnet insertion hole 27t (magnet insertion hole 27v) have a larger angle than the rotor core 21 in FIG. It is arranged in a V shape so as to form The inner peripheral portion 55 is formed so as to spread in the circumferential direction around the central axis 101 from the end portion of the intermediate portion 54, and the inner diameter side flux barrier 52 is configured by the inner peripheral portion 55.

  According to the motor generator in the second embodiment of the present invention configured as described above, the effects described in the first embodiment can be obtained in the same manner.

  A new motor generator may be configured by appropriately combining the various motor generator structures in the first and second embodiments described above.

  The embodiment disclosed this time should be considered as illustrative in all points and not restrictive. The scope of the present invention is defined by the terms of the claims, rather than the description above, and is intended to include any modifications within the scope and meaning equivalent to the terms of the claims.

  The present invention is mainly applied to a vehicle including a motor as a power source.

  DESCRIPTION OF SYMBOLS 10 Motor generator, 12 Terminal block, 13 Inverter, 14 Battery, 15 Reduction mechanism, 16 Differential mechanism, 17 Drive shaft receiving part, 21 Rotor core, 21a, 21b, 31a, 31b End surface, 21c Outer peripheral surface, 22, 32 Electrical steel sheet, 26 Permanent magnet, 27 Magnet insertion hole, 28 Hollow hole, 31 Stator core, 36 Coil, 36p, 36q Coil end part, 41 Rotor shaft, 42 Hollow part, 43 Oil supply hole, 46, 47 Bearing, 48 Oil pump, 51 Outside Diameter side flux barrier, 52 Inner diameter side flux barrier, 53 Outer peripheral part, 54 Intermediate part, 55 Inner peripheral part, 61 Resin mold part, 71 Slit body part, 71p One end, 71q The other end, 72, 73 Slit end part, 76 Slit, 81 outer circumference Ridge, 86 mold apparatus, 87 upper mold, 87m, 88m end 89 resin portion.

Claims (6)

A rotor core having a shaft fitted to the inner periphery and having an outer peripheral surface;
A plurality of magnets provided on the rotor core;
The rotor core is provided with a gap in the circumferential direction around the rotation axis, and a plurality of insertion holes into which the magnet is inserted are formed.
The magnet is held in the insertion hole so as to provide a first space and a second space disposed on the outer peripheral side of the first space at both ends of the magnet,
The plurality of insertion holes include a first insertion hole and a second insertion hole provided adjacent to the first insertion hole, and when the rotor core is cut by a plane orthogonal to the rotation axis, The cross-sectional shape of the first insertion hole and the second insertion hole has a V shape that is convex on the outer peripheral side and concave on the inner peripheral side,
The rotor core is further formed with a slit provided at a central position between the first insertion hole and the second insertion hole,
When cut by a plane perpendicular to the rotor core to the rotation axis, the cross-sectional shape of the slit, from the outer peripheral surface, have a slit body portion extending in the radial direction around the rotational axis of the rotor core,
When the rotor core is cut by a plane orthogonal to the rotation axis, the cross-sectional shape of the slit is provided at an end of the slit body, and the slit body in the circumferential direction around the rotation axis of the rotor core Further having a slit end having a greater width,
A rotating electrical machine in which the entire slit end is disposed between an inner peripheral end of the first space and an outer peripheral end of the first space in a radial direction centered on the rotation axis of the rotor core . The rotating electrical machine according to claim 1 , wherein the slit end portion has a circular cross-sectional shape. The plurality of insertion holes further include a third insertion hole provided on the opposite side of the second insertion hole across the first insertion hole,
In the circumferential direction around the rotation axis of the rotor core, the first insertion hole and the second insertion hole are arranged with a first interval, and the first insertion hole and the third insertion hole are the are arranged has a smaller second distance than the first distance, the rotary electric machine according to claim 1 or 2. The plurality of insertion holes further include a third insertion hole provided on the opposite side of the second insertion hole across the first insertion hole,
When the rotor core is cut along a plane orthogonal to the rotation axis thereof, the first insertion hole and the third insertion hole have a V-shaped cross section that is concave on the outer peripheral side and convex on the inner peripheral side. The rotating electrical machine according to any one of claims 1 to 3 . The slit body portion thereof along the rotation axis direction shear force is formed by being acted, rotating electric machine according to any one of claims 1 to 4 to the rotor core. When cut by a plane perpendicular to the rotor core to the rotation axis, the first space has a sectional area greater than the second space, the electric rotating machine according to any one of claims 1-5.

Images