JP2015056911A - Rotor and rotary electric machine having the same - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a rotor having a bridge made of nonmagnetic material and arranged between adjacent permanent magnets, capable of suppressing concentration of stress generated in the rotor.SOLUTION: In the magnet insertion hole 22 of a rotor core 30, a bridge 36 made of a nonmagnetic material is arranged so as to bridge the rotor core 30 on the inner side of the magnet insertion hole 22 in a radial direction R and the rotor core 30 on the outer side thereof in the radial direction R between adjacent permanent magnets 24. A fixation structure 38 between the bridge 36 and the rotor core 30 on the inner side in the radial direction R is formed so as to allow a displacement of the bridge, compared with a fixation structure 40 between the bridge 36 and the rotor core 30 on the outer side in the radial direction R. This constitution can prevent an excessive stress from occurring in the fixation structure 38 and an outer peripheral bridge 34 on the outer peripheral surface of the rotor core 30.

Description

  The present invention relates to a rotor and a rotating electrical machine including the rotor, and more particularly to an improvement in the structure of a bridge provided between permanent magnets embedded in a rotor core.

  Conventionally, the rotor has a rotor core fixed to the rotor shaft and a permanent magnet inserted into a magnet insertion hole formed in the rotor core, and the rotor is operated by electromagnetic action between the rotor and the rotating magnetic field. There is known a rotating electric machine that rotates the motor.

  The following Patent Document 1 describes a configuration in which a pair of permanent magnets having the same polarity are inserted into one magnet insertion hole with a space therebetween, and a non-magnetic bridge is inserted between the permanent magnets. Yes. The non-magnetic bridge is fixed to the rotor core so as to bridge the radially inner rotor core and the radially outer rotor core from the magnet insertion hole.

JP 2009-201269 A

  In the rotor disclosed in Patent Document 1, as described above, the bridge arranged between the permanent magnets is made of a non-magnetic member, thereby reducing the magnetic flux of the permanent magnet that leaks through the bridge. ing. However, the problem regarding the stress distribution of the rotor caused by using a non-magnetic bridge which is a member different from the rotor core is not considered.

  Specifically, when the rotating electrical machine is driven, the non-magnetic bridge is displaced radially outward by centrifugal force, so that it is formed between the outer peripheral end of the magnet insertion hole and the outer peripheral surface of the rotor core. There is a problem that excessive stress is generated in the outer bridge. In order to solve this problem, it is conceivable to employ a structure in which the bridge is firmly fixed to the rotor core in order to prevent the movement of the non-magnetic bridge. However, in this structure, although the stress concentration in the outer bridge is alleviated, an excessive stress is generated at the fixed portion between the non-magnetic bridge and the rotor core.

  The objective of this invention is providing the rotor which can suppress the stress concentration in the rotor which generate | occur | produces with the bridge | bridging of the nonmagnetic material provided between adjacent permanent magnets, and a rotary electric machine provided with this rotor.

  The present invention is inserted into the magnet insertion hole so as to be positioned between the rotor core, the permanent magnet inserted in the circumferential direction in the magnet insertion hole formed in the rotor core, and the adjacent permanent magnet, In a rotor having a non-magnetic bridge that is fixed so as to bridge a radially inner rotor core and a radially outer rotor core from a magnet insertion hole, the bridge and the rotor core fixing structure on the radially inner side have a diameter The bridge is configured to allow displacement of the bridge with respect to the rotor core as compared with the structure of fixing the bridge and rotor core on the outer side in the direction.

  In addition, each of the radially inner and outer fixing structures includes a locking portion in which an end portion of the bridge is locked to the rotor core, and the number of the radially inner locking portions is the number of the radially outer locking portions. Fewer than the number of locking portions.

  Moreover, it is suitable that it is a rotary electric machine provided with a rotor.

  According to the rotor of the present invention and the rotating electrical machine including the rotor, stress concentration in the rotor generated by a non-magnetic bridge provided between adjacent permanent magnets can be suppressed.

It is a figure which shows the structure of the rotary electric machine which concerns on this embodiment. It is a top view of the rotor which concerns on this embodiment. It is the top view which expanded a part of rotor.

  Hereinafter, embodiments of a rotor according to the present invention and a rotating electrical machine including the rotor will be described with reference to the drawings. FIG. 1 is a diagram illustrating a configuration of a rotating electrical machine according to the present embodiment.

  The rotating electrical machine 10 is used as a prime mover of a vehicle, for example. The rotating electrical machine 10 includes a rotor 14 fixed to the rotor shaft 12 and a stator 18 fixed to the case 16 of the rotating electrical machine 10 so as to surround the rotor 14.

  The rotor 14 is a cylindrical magnetic body concentric with the rotor shaft 12, and is configured by, for example, stacking laminated steel plates in the axial direction 20. In the laminated steel plate, a magnet insertion hole 22 extending in the axial direction 20 is formed, and a permanent magnet 24 is inserted and disposed in the magnet insertion hole 22. The detailed configuration of the rotor 14 will be described later.

  The rotor shaft 12 is rotatably supported by a bearing 26 provided in the case 16. The rotor shaft 12 of the present embodiment is an output shaft that transmits the output of the rotating electrical machine 10 to drive wheels (not shown) of the vehicle. The rotor shaft 12 and the drive wheels are connected via a gear mechanism (not shown). Connected.

  The stator 18 is disposed with a gap around the rotor 14. The stator 18 has magnetic poles (not shown) that protrude toward the inner peripheral side of the stator 18 and are arranged at a predetermined interval in the circumferential direction. A coil 28 formed by winding a conductive wire around a magnetic pole is disposed in a slot which is a space between the magnetic poles. FIG. 1 shows a coil 28, that is, a coil end, that bridges between the slots at both ends of the stator 18. When the coil 28 is energized, a rotating magnetic field is generated in the stator 18, and a force attracted by the rotating magnetic field is generated in the rotor 14 having the permanent magnet 24, so that the rotor 14 rotates.

  Next, the configuration of the rotor 14 will be described with reference to FIGS. FIG. 2 is a plan view of the rotor 14 of the present embodiment. FIG. 3 is an enlarged plan view of a part of the rotor 14. More specifically, FIG. 3 is an enlarged plan view of one magnetic pole portion of the rotor 14. In this embodiment, the rotor 14 has eight magnetic poles. However, the present invention is not limited to the number of magnetic poles of 8 poles. In the figure, an arrow θ indicates the circumferential direction, and an arrow R indicates the radial direction.

  As shown in FIG. 2, the rotor 14 includes a rotor core 30 and a permanent magnet 24 embedded in the rotor core 30. The rotor core 30 is formed in an annular shape, and a through hole 32 into which the rotor shaft 12 is inserted is formed at the center of the rotor core 30.

  The rotor core 30 is formed by laminating electromagnetic steel plates in the axial direction 20 (shown in FIG. 1). Specifically, the rotor core 30 is formed by punching a thin plate-shaped electromagnetic steel sheet with a press, laminating a predetermined number of the punched electromagnetic steel sheets in the axial direction, and pressing the plurality of laminated electromagnetic steel sheets with pressure caulking or the like. Formed by processing. In the present embodiment, the case where the rotor core 30 is configured by laminating electromagnetic steel plates has been described. However, the present invention is not limited to this configuration, and if the rotor core 30 is a magnetic body, the rotor core 30 is formed from a dust core. May be.

  The rotor core 30 is formed with a magnet insertion hole 22 into which the permanent magnet 24 is inserted. The magnet insertion hole 22 includes a first magnet insertion hole 22a that extends along a tangent line in the circumferential direction θ, and a substantially V-shaped second magnet insertion hole 22b that protrudes inward in the radial direction R. The first magnet insertion hole 22a is formed in the rotor core 30 on the outer side in the radial direction R from the second magnet insertion hole 22b. The first and second magnet insertion holes 22a and 22b are formed in units of eight, which is the number of magnetic poles of the rotor 14, and are arranged at equal intervals in the circumferential direction θ. In addition, the area | region of the rotor core 30 located in the radial direction R outer side from the 2nd magnet insertion hole 22b is only described as the outer rotor core 30a. And the area | region of the rotor core 30 located inside radial direction R from the 2nd magnet insertion hole 22b is only described as the inner rotor core 30b.

  Two permanent magnets 24 are inserted into the second magnet insertion hole 22b at intervals in the circumferential direction θ. In addition, one permanent magnet 24 is inserted into the first magnet insertion hole 22a located on the outer side in the radial direction R from the second magnet insertion hole 22b. A total of three permanent magnets 24 inserted into the first and second magnet insertion holes 22a and 22b form one magnetic pole (N pole in FIG. 3). That is, the polarity on the outer side of the radial direction R in the permanent magnet 24 in the first magnet insertion hole 22a and the polarity on the outer rotor core 30a side in the permanent magnet 24 in the second magnet insertion hole 22b coincide. These permanent magnets 24 form one magnetic pole.

  As described above, the second magnet insertion hole 22b is formed in a substantially V-shape that is convex inward in the radial direction R. The distance between both end portions of the second magnet insertion hole 22b on the outer side in the radial direction R and the outer peripheral surface of the rotor core 30 is thin and thin. Hereinafter, this narrow and thin region is referred to as an outer peripheral bridge 34. The outer bridge 34 is formed to bridge the outer rotor core 30a and the inner rotor core 30b.

  Further, a bridge 36 that bridges the outer rotor core 30a and the inner rotor core 30b is inserted in the central portion of the second magnet insertion hole 22b in the circumferential direction θ. That is, the bridge 36 bridges adjacent rotor cores 30 in the radial direction R across the second magnet insertion hole 22b. The bridge 36 is a member different from the rotor core 30 and is made of a nonmagnetic material such as stainless steel. The non-magnetic bridge 36 is inserted between the two permanent magnets 24 and fixed to the outer rotor core 30a and the inner rotor core 30b, respectively.

  In this embodiment, the non-magnetic bridge 36 and the inner rotor core 30b are fixed to a fixing structure 38, which is different from the fixing structure 40 to which the bridge 36 and the outer rotor core 30a are fixed. It is formed so as to allow displacement. That is, the fixing structure 38 on the inner rotor core 30b side is formed to have a strength that allows the non-magnetic bridge 36 to be easily displaced, and the fixing structure 40 on the outer rotor core 30a side is difficult to displace the non-magnetic bridge 36. Formed with strength.

  As described above, the fixed structure 40 on the outer rotor core 30a side is configured such that the non-magnetic bridge 36 is difficult to displace, thereby suppressing the amount of displacement of the non-magnetic bridge 36 outward in the radial direction R. Therefore, the stress concentration in the outer bridge 34 caused by the amount of displacement can be reduced. Further, the fixing structure 38 on the inner rotor core 30b side has a structure in which the non-magnetic bridge 36 is easily displaced, so that the fixing structure 38 is fixed as compared with the case where the structure firmly fixed to the fixing structure 38 is adopted. The stress concentration generated in 38 can be relaxed.

  Thus, according to the rotor 14 of the present embodiment, the outer bridge 34 can be obtained by making the fixing structure 38 on the inner rotor core 30b side a looser fixing structure and the fixing structure 40 on the outer rotor core 30a side a tighter fixing structure. It is possible to prevent an excessive stress from being generated in the fixed structure 38. In an experiment using the rotor 14 of the present embodiment, excessive stress generated in the outer peripheral bridge 34 or the fixing structure 38 described in the related art is dispersed in both regions of the outer peripheral bridge 34 and the fixing structure 38, and the rotor 14. It was found that the stress was reduced as a whole.

  Next, a specific configuration of the fixing structures 38 and 40 will be described with reference to FIG. Each of the fixing structures 38 and 40 has a locking portion 42 where the end portion of the non-magnetic bridge 36 is locked to the rotor core 30. As shown in FIG. 3, the locking portion 42 includes a convex portion 44 that protrudes from the bridge 36 body, and a concave portion 46 that is formed on the rotor core 30 and into which the convex portion 44 fits. The convex portion 44 has a hooking portion 44 a that spreads on both sides of the circumferential direction θ, and the hooking portion 44 a is hooked on the edge of the concave portion 46, thereby restricting the separation between the convex portion 44 and the concave portion 46. With this configuration, the non-magnetic bridge 36 is inserted into the second magnet insertion hole 22 b, the convex portion 44 fits into the concave portion 46, and the non-magnetic bridge 36 is locked and fixed to the rotor core 30.

  The number of locking portions 42 on the inner rotor core 30b side is two, and the number of locking portions 42 on the outer rotor core 30a side is six. Thus, by making the number of the locking portions 42 on the inner rotor core 30b side smaller than the number of the locking portions 42 on the outer rotor core 30a side, the fixing structure 38 on the inner rotor core 30b side is fixed on the outer rotor core 30a side. The fastening force is smaller than that of the structure 40. Therefore, the fixing structure 38 on the inner rotor core 30b side can permit displacement from the non-magnetic bridge 36.

  In the present embodiment, the case where there are six locking portions 42 on the outer rotor core 30a side and two locking portions 42 on the inner rotor core 30b side has been described, but the present invention is not limited to this configuration. If the number of the locking portions 42 on the inner rotor core 30b side is less than the number of the locking portions 42 on the outer rotor core 30a side, the fixing structure 38 of the inner rotor core 30b is relative to the rotor core 30 compared to the fixing structure 40 of the outer rotor core 30a. The displacement of the non-magnetic bridge 36 can be allowed.

  In the present embodiment, as shown in FIG. 3, two permanent magnets 24 are inserted into the second magnet insertion hole 22 b, and a non-magnetic bridge 36 is disposed between these permanent magnets 24. Although the case has been described, the present invention is not limited to this configuration. If the non-magnetic bridge 36 is arranged between the adjacent permanent magnets 24, three or more permanent magnets 24 are inserted into the second magnet insertion hole 22b with a gap between them. A non-magnetic bridge 36 can be disposed in the gap.

  Moreover, although this embodiment demonstrated the case where one magnetic pole contains the permanent magnet 24 inserted in the 1st magnet insertion hole 22a, this invention is not limited to this structure. One magnetic pole may be composed of only the plurality of permanent magnets 24 inserted into the second magnet insertion hole 22b without the permanent magnet 24 of the first magnet insertion hole 22a.

  In the present embodiment, the case where the shape of the second magnet insertion hole 22b is a substantially V-shape projecting inward in the radial direction R has been described, but the present invention is not limited to this configuration. As long as the non-magnetic bridge 34 can be disposed between the adjacent permanent magnets 24 arranged in the circumferential direction θ, the second magnet insertion hole 22b may have another shape.

  DESCRIPTION OF SYMBOLS 10 Rotating electrical machine, 12 Rotor shaft, 14 Rotor, 18 Stator, 22 Magnet insertion hole, 24 Permanent magnet, 28 coils, 30 Rotor core, 32 Through-hole, 34 Perimeter bridge, 36 Non-magnetic bridge, 38, 40 Fixing structure, 42 locking part, 44 convex part, 46 concave part.

Claims (3)

Rotor core,
Permanent magnets inserted into the magnet insertion holes formed in the rotor core at intervals in the circumferential direction;
A non-magnetic bridge that is inserted into the magnet insertion hole so as to be positioned between adjacent permanent magnets and fixed to bridge the radially inner rotor core and the radially outer rotor core from the magnet insertion hole;
In a rotor having
The bridge and rotor core fixing structure on the radially inner side is formed so as to allow displacement of the bridge relative to the rotor core as compared to the bridge and rotor core fixing structure on the radially outer side.
A rotor characterized by that. The rotor according to claim 1, wherein
The radial inner and outer fixing structures each have a locking portion in which an end of the bridge is locked to a rotor core,
The number of radially inner locking portions is less than the number of radially outer locking portions,
A rotor characterized by that.   A rotating electrical machine comprising the rotor according to claim 1.

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