Rotary electric machine and rotor of the same

Abstract

To provide a rotary electric machine capable of reducing tensile stress generated in a yoke connecting part of a rotor core, and a rotor thereof.SOLUTION: Each yoke connecting portion 41d includes a bridge connecting column 41g and a pair of first bridges 41h. The bridge connecting column 41g protrudes from an inner-diameter-side yoke portion 41b along a radial direction of the rotor core 41. The bridge connecting column 41g connects the pair of first bridges 41h and the inner-diameter-side yoke portion 41b. The pair of first bridges 41h is each inclined by an angle θ with respect to the radial direction of the rotor core 41.SELECTED DRAWING: Figure 4

Description

[Technical Field]

[0001] The present disclosure relates to a rotating electric machine and a rotor thereof. [Background technology]

[0002] In the rotor of a conventional permanent magnet embedded motor, a linear bridge is formed along the inter-pole center line in the end gap between two adjacent magnet insertion holes in the rotor core (see, for example, Patent Document 1). [Prior art documents] [Patent documents]

[0003] [Patent Document 1] International Publication No. 2012 / 026032 Summary of the Invention [Problem to be solved by the invention]

[0004] In the rotor of a conventional interior permanent magnet motor as described above, when the shaft is press-fitted into the rotor core, the rotor core is expanded radially outward, which stretches the bridges along the radial direction of the rotor core, generating high tensile stress in the bridges, which can lead to breakage.

[0005] The present disclosure has been made to solve the above-mentioned problems, and aims to provide a rotating electric machine and a rotor therefor that can reduce tensile stress occurring at the yoke connection portion of the rotor core. [Means for solving the problem]

[0006] The rotor of the rotating electric machine according to the present disclosure comprises a cylindrical rotor core provided with a plurality of slots, and a plurality of magnets inserted into the plurality of slots at intervals circumferentially of the rotor core, the rotor core having an inner diameter side yoke portion located radially inward of the rotor core relative to the plurality of magnets, a plurality of outer diameter side yoke portions each located radially outside the plurality of magnets of the rotor core, and a plurality of yoke connecting portions each connecting the inner diameter side yoke portion and the plurality of outer diameter side yoke portions, each yoke connecting portion having a pair of first bridges connected to two adjacent outer diameter side yoke portions of the plurality of outer diameter side yoke portions, and the pair of first bridges at each yoke connecting portion are each inclined relative to the radial direction of the rotor core. [Effects of the Invention]

[0007] According to the present disclosure, it is possible to reduce the tensile stress occurring at the yoke connection portion of the rotor core. [Brief explanation of the drawings]

[0008] [Figure 1] 1 is a half cross-sectional view showing a rotating electric machine according to a first embodiment. [Figure 2] 2 is a perspective view showing the shaft and rotor assembly of FIG. 1 with the first end plate and second end plate removed. FIG. [Figure 3] FIG. 3 is an enlarged perspective view showing a main part of FIG. 2. [Figure 4] 4 is a front view of a part of the rotor core of FIG. 3, viewed along the axis of the rotor core. [Figure 5] FIG. 5 is a front view showing a state in which a magnet is inserted into the slot of FIG. [Figure 6] 10 is a graph showing the relationship between the angle of each first bridge relative to the center line of the bridge connection pillar and the stress generated in the yoke connection portion in the first embodiment. [Figure 7] FIG. 10 is a perspective view showing a main part of a rotor of a rotary electric machine according to a second embodiment. [Figure 8] 8 is a front view of a part of the rotor core of FIG. 7, viewed along the axis of the rotor core. [Figure 9] FIG. 9 is a front view showing a state in which a magnet is inserted into the slot in FIG. 8. DETAILED DESCRIPTION OF THE INVENTION

[0009] Hereinafter, embodiments will be described with reference to the drawings. Embodiment 1 1 is a half cross-sectional view showing a rotating electric machine according to Embodiment 1. The rotating electric machine of Embodiment 1 includes a housing 10, a first bearing 21, a second bearing 22, a shaft 23, a stator 30, and a rotor 40.

[0010] The housing 10 has a housing main body 11 and a disk-shaped lid member 12. The housing main body 11 has a cylindrical portion 11a and a disk-shaped bottom plate portion 11b. The bottom plate portion 11b is provided at one axial end of the cylindrical portion 11a. The lid member 12 is provided at the other axial end of the cylindrical portion 11a.

[0011] The first bearing 21 is held in the center of the bottom plate portion 11b. The second bearing 22 is held in the center of the cover member 12. The shaft 23 is rotatably supported by the housing 10 via the first bearing 21 and the second bearing 22.

[0012] The stator 30 is fixed to the inner periphery of the cylindrical portion 11a and includes a cylindrical stator core 31 and a coil 32.

[0013] The rotor 40 is fixed to the shaft 23. The rotor 40 rotates integrally with the shaft 23 relative to the housing 10.

[0014] The rotor 40 also has a cylindrical rotor core 41, a plurality of flat plate-shaped magnets 42, a disk-shaped first end plate 43, and a disk-shaped second end plate 44.

[0015] The shaft 23 is press-fitted into the center of the rotor core 41. This fixes the rotor core 41 to the shaft 23. The outer peripheral surface of the rotor core 41 faces the inner peripheral surface of the stator core 31. The rotor core 41 is made by laminating multiple electromagnetic steel plates to suppress eddy currents generated inside.

[0016] The plurality of magnets 42 are embedded in the rotor core 41. A permanent magnet is used as each of the magnets 42. That is, the rotor 40 is a permanent magnet type rotor.

[0017] The first end plate 43 is fixed to one axial end surface of the rotor core 41. The second end plate 44 is fixed to the other axial end surface of the rotor core 41. The axial direction of the rotor core 41 is the direction along the axis C1 of the rotor core 41, which is the vertical direction in FIG. 1. The axis C1 of the rotor core 41 also coincides with the rotation center of the shaft 23 and the rotor 40.

[0018] The first end plate 43 and the second end plate 44 prevent the magnets 42 from jumping out of the rotor core 41. The first end plate 43 and the second end plate 44 are each made of a non-magnetic material.

[0019] 2 is a perspective view showing the state in which the first end plate 43 and the second end plate 44 have been removed from the assembly of the shaft 23 and the rotor 40 in FIG. 1. The magnets 42 are spaced apart from one another in the circumferential direction of the rotor core 41 and are arranged at equal pitches in the circumferential direction of the rotor core 41. The circumferential direction of the rotor core 41 is the direction along the circumference of a circle centered on the axis C1 of the rotor core 41.

[0020] Figure 3 is an enlarged perspective view of the main part of Figure 2. A plurality of slots 41a are provided in the rotor core 41. The plurality of slots 41a are provided at equal pitches on the same circumference centered on the axis C1. A plurality of magnets 42 are inserted into the plurality of slots 41a, respectively.

[0021] The rotor core 41 has an inner diameter side yoke portion 41b, a plurality of outer diameter side yoke portions 41c, and a plurality of yoke connecting portions 41d.

[0022] The inner diameter side yoke portion 41b is a portion located radially inward of the rotor core 41 relative to the multiple magnets 42. The radial direction of the rotor core 41 is perpendicular to the axis C1. The inner diameter side yoke portion 41b forms a magnetic circuit between adjacent magnets 42.

[0023] The multiple outer diameter side yoke portions 41c are portions located outside the multiple magnets 42 in the radial direction of the rotor core 41. The multiple outer diameter side yoke portions 41c transmit magnetic flux from the multiple magnets 42 to the stator 30. That is, a magnetic pole is formed on each of the outer diameter side yoke portions 41c.

[0024] The plurality of yoke connecting portions 41d connect the inner diameter side yoke portion 41b and the plurality of outer diameter side yoke portions 41c, respectively.

[0025] Fig. 4 is a front view of a part of rotor core 41 of Fig. 3, seen along axis C1 of rotor core 41. Fig. 5 is a front view showing a state in which magnets 42 are inserted into slots 41a of Fig. 4.

[0026] Each slot 41a has a magnet insertion portion 41e and a pair of flux barriers 41f. The magnet insertion portion 41e is a portion into which a magnet 42 is inserted. The pair of flux barriers 41f are located on both sides of the magnet insertion portion 41e in the circumferential direction of the rotor core 41. Each of the pair of flux barriers 41f is an air gap that suppresses leakage of magnetic flux to the other magnetic pole.

[0027] Each yoke connecting portion 41d has a bridge connecting post 41g, a pair of first bridges 41h, and a pair of stopper portions 41i.

[0028] The bridge connecting posts 41g protrude outward from the inner diameter side yoke portion 41b in the radial direction of the rotor core 41. In each yoke connecting portion 41d, the center line C2 of the bridge connecting post 41g is aligned with the radial direction of the rotor core 41.

[0029] In each yoke connecting portion 41d, both end faces of the bridge connecting post 41g in the circumferential direction of the rotor core 41 are parallel to the center line C2 of the bridge connecting post 41g.

[0030] In each yoke connector 41d, the pair of first bridges 41h are connected to the two adjacent outer diameter side yoke sections 41c and the bridge connecting posts 41g. That is, in each yoke connector 41d, the bridge connecting posts 41g connect the pair of first bridges 41h and the inner diameter side yoke section 41b.

[0031] The pair of first bridges 41h in each yoke connecting portion 41d are inclined by an angle θ relative to the radial direction of the rotor core 41. That is, in each yoke connecting portion 41d, the pair of first bridges 41h are inclined by the angle θ in opposite directions relative to the center line C2 of the bridge connecting post 41g.

[0032] The angle θ is an acute angle. In each yoke connecting portion 41d, the bridge connecting post 41g and the pair of first bridges 41h form a Y shape.

[0033] Each stopper portion 41i protrudes from the yoke connecting portion 41d in the circumferential direction of the rotor core 41 and abuts against the magnet 42. As a result, each stopper portion 41i prevents the magnet 42 from entering the flux barrier 41f.

[0034] In such a rotor 40, when the shaft 23 is fitted to the rotor core 41 by press fitting or shrink fitting, the rotor core 41 is expanded by the shaft 23, and expansion is concentrated at the yoke connecting portion 41d.

[0035] In contrast to this, in the first embodiment, a pair of first bridges 41h are provided at each yoke connecting portion 41d, and the pair of first bridges 41h at each yoke connecting portion 41d are inclined relative to the radial direction of the rotor core.

[0036] Therefore, the elongation occurring in the yoke connector 41d is absorbed by the deformation of the pair of first bridges 41h, and the tensile stress occurring in the yoke connector 41d can be reduced, thereby suppressing breakage of the yoke connector 41d and improving the quality of the rotating electric machine.

[0037] In each yoke connecting portion 41d, the pair of first bridges 41h and the inner diameter side yoke portion 41b are connected by bridge connecting posts 41g. The center line C2 of the bridge connecting posts 41g is aligned with the radial direction of the rotor core 41. The pair of first bridges 41h are inclined in opposite directions relative to the center line C2.

[0038] Therefore, it is possible to increase the length of magnets 42 in the circumferential direction of rotor core 41 to increase torque, while enlarging flux barriers 41f to sufficiently suppress magnetic flux leakage to other magnetic poles, thereby improving the output of the rotating electric machine.

[0039] Furthermore, at each yoke connecting portion 41d, both end faces of the bridge connecting post 41g in the circumferential direction of the rotor core 41 are parallel to the center line C2. This more reliably suppresses magnetic flux leakage to other magnetic poles and also suppresses stress concentration due to external forces such as centrifugal force.

[0040] FIG. 6 is a graph showing the relationship between the angle θ of each first bridge 41h with respect to the center line C2 of the bridge connecting post 41g and the stress generated in the yoke connecting portion 41d.

[0041] 6, the smaller the angle θ, the smaller the stress generated in the yoke connecting portion 41d. However, if the angle θ is too small, the magnetic flux leakage to the adjacent magnetic pole increases.

[0042] Furthermore, as the angle θ increases, the stress generated in the yoke connecting portion 41d also increases. When the angle θ is 50 degrees, the maximum stress is a tensile stress, but when the angle θ is 60 degrees, the maximum stress is a bending stress.

[0043] For these reasons, it is preferable that the angle θ formed by the pair of first bridges 41h and the center line C2 of the bridge connecting post 41g in each yoke connector 41d be between 20 degrees and 55 degrees, respectively, which reduces stress generated in each yoke connector 41d and efficiently suppresses magnetic flux leakage.

[0044] Embodiment 2 Next, Fig. 7 is a perspective view showing a main portion of rotor 40 of a rotary electric machine according to embodiment 2. Fig. 8 is a front view of a part of rotor core 41 of Fig. 7, viewed along axis C1 of rotor core 41. Fig. 9 is a front view showing a state in which magnets 42 are inserted into slots 41a of Fig. 8.

[0045] Each yoke connector 41d of the second embodiment further includes a second bridge 41j in addition to a bridge connector post 41g, a pair of first bridges 41h, and a pair of stopper portions 41i.

[0046] In each yoke connector 41d, the second bridge 41j connects a pair of first bridges 41h. Specifically, the second bridge 41j connects the outer diameter side ends of the pair of first bridges 41h. The outer diameter side end of each first bridge 41h is the end on the outer diameter side yoke section 41c side, i.e., the end opposite the bridge connecting pillar 41g.

[0047] In each yoke connecting portion 41d, an inter-bridge hole 41k is provided between the pair of first bridge 41h and second bridge 41j.

[0048] Other configurations in the second embodiment are the same as those in the first embodiment.

[0049] This configuration also provides the same effects as in embodiment 1. Furthermore, at each yoke connector 41d, the pair of first bridges 41h are connected by the second bridges 41j, which reduces the stress amplitude of the pair of first bridges 41h at each yoke connector 41d.

[0050] Therefore, fatigue damage to each yoke connecting portion 41d due to repeated loads generated during operation can be suppressed even in rotating electrical machines with high rotation speeds or high torque densities, etc. Therefore, a more robust and high-quality rotating electrical machine can be provided.

[0051] In the first and second embodiments, methods of fixing each magnet 42 to the rotor core 41 include filling the slot 41a with resin to fix it, pressing it into the slot 41a, sandwiching it between the first end plate 43 and the second end plate 44, and the like.

[0052] In the first and second embodiments, the number of magnets 42 is not particularly limited.

[0053] The above describes in detail preferred embodiments, but the present invention is not limited to the above-described embodiments, and various modifications and substitutions can be made to the above-described embodiments without departing from the scope of the claims.

[0054] Various aspects of the present disclosure are summarized below as appendices.

[0055] (Appendix 1) a cylindrical rotor core having a plurality of slots; and a plurality of magnets inserted into the plurality of slots at intervals in the circumferential direction of the rotor core; Equipped with The rotor core is an inner diameter side yoke portion located radially inside the rotor core with respect to the plurality of magnets; a plurality of outer diameter side yoke portions each positioned outside the plurality of magnets in the radial direction of the rotor core; a plurality of yoke connecting portions respectively connecting the inner diameter side yoke portion and the plurality of outer diameter side yoke portions; It has each of the yoke connecting portions has a pair of first bridges connected to two adjacent outer diameter side yoke portions among the plurality of outer diameter side yoke portions, A rotor for a rotating electric machine, wherein the pair of first bridges at each of the yoke connecting portions are inclined relative to the radial direction of the rotor core. (Appendix 2) Each of the yoke connectors is a bridge connecting column that protrudes from the inner diameter side yoke portion along the radial direction of the rotor core and connects the pair of first bridges and the inner diameter side yoke portion; and At each of the yoke connecting portions, a center line of the bridge connecting column extends along a radial direction of the rotor core; 2. The rotor for a rotating electric machine according to claim 1, wherein the pair of first bridges are inclined in opposite directions relative to the center line of the bridge connecting pole. (Appendix 3) 3. The rotor for a rotating electric machine according to claim 2, wherein the angles formed by the pair of first bridges with respect to the center line of the bridge connection column in each of the yoke connection portions are equal to or greater than 20 degrees and equal to or less than 55 degrees. (Appendix 4) 4. The rotor for a rotating electric machine according to claim 2, wherein, in each of the yoke connecting portions, both end faces of the bridge connecting posts in the circumferential direction of the rotor core are parallel to a center line of the bridge connecting posts. (Appendix 5) Each of the yoke connectors further includes a second bridge connecting the pair of first bridges, 5. The rotor for a rotating electric machine according to claim 1, wherein an inter-bridge hole is provided between the pair of first bridges and the pair of second bridges in each of the yoke connecting portions. (Appendix 6) A rotor according to any one of appendices 1 to 5. A rotating electric machine comprising: [Explanation of symbols]

[0056] 40 rotor, 41 rotor core, 41a slot, 41b inner diameter side yoke portion, 41c outer diameter side yoke portion, 41d yoke connecting portion, 41g bridge connecting column, 41h first bridge, 41j second bridge, 41k inter-bridge hole, 42 magnet.

Claims

1. a cylindrical rotor core having a plurality of slots; and a plurality of magnets inserted into the plurality of slots at intervals in the circumferential direction of the rotor core; Equipped with The rotor core is an inner diameter side yoke portion located radially inside the rotor core with respect to the plurality of magnets; a plurality of outer diameter side yoke portions each positioned outside the plurality of magnets in the radial direction of the rotor core; a plurality of yoke connecting portions respectively connecting the inner diameter side yoke portion and the plurality of outer diameter side yoke portions; It has each of the yoke connecting portions has a pair of first bridges connected to two adjacent outer diameter side yoke portions among the plurality of outer diameter side yoke portions, A rotor for a rotating electric machine, wherein the pair of first bridges at each of the yoke connecting portions are inclined relative to the radial direction of the rotor core.

2. Each of the yoke connectors is a bridge connecting column that protrudes from the inner diameter side yoke portion along the radial direction of the rotor core and connects the pair of first bridges and the inner diameter side yoke portion; and At each of the yoke connecting portions, a center line of the bridge connecting column extends along a radial direction of the rotor core; 2. The rotor for a rotating electric machine according to claim 1, wherein the pair of first bridges are inclined in opposite directions relative to the center line of the bridge connecting post.

3. 3. The rotor for a rotating electric machine according to claim 2, wherein the angles formed by the pair of first bridges with respect to the center line of the bridge connection post at each of the yoke connection portions are equal to or greater than 20 degrees and equal to or less than 55 degrees.

4. 3. The rotor for a rotating electric machine according to claim 2, wherein, at each of the yoke connecting portions, both end faces of the bridge connecting posts in the circumferential direction of the rotor core are parallel to a center line of the bridge connecting posts.

5. Each of the yoke connectors further includes a second bridge connecting the pair of first bridges, 5. The rotor for a rotating electric machine according to claim 1, wherein an inter-bridge hole is provided between the pair of first bridges and the pair of second bridges in each of the yoke connecting portions.

6. A rotor according to any one of claims 1 to 4. A rotating electric machine comprising:

7. The rotor according to claim 5 . A rotating electric machine comprising:

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