Rotor core

Abstract

To provide a rotor core capable of suppressing deformation of the rotor core and generation of residual stress in the rotor core when a bridge member provided separately from the rotor core is assembled to the rotor core.SOLUTION: The rotor core has a plurality of magnet insertion portions and includes a magnet insertion hole into which a bridge member formed of a non-magnetic body is inserted. The rotor core includes a bridge insertion portion which is provided at a position dividing the inside of the magnet insertion hole into a plurality of regions each including the magnet insertion portion and into which the bridge member is inserted. In the rotor core, a resin portion is provided in a portion excluding the magnet insertion portion and the bridge insertion portion in the magnet insertion hole.SELECTED DRAWING: Figure 2

Description

[Technical Field]

[0001] The present invention relates to a rotor core. [Background technology]

[0002] Conventionally, rotor cores have been known in which bridge members are arranged to divide the interior of the permanent magnet holes (see, for example, Patent Document 1). The bridge members in Patent Document 1 are made of a non-magnetic material and are attached by press fitting or shrink fitting into fitting holes that are part of the permanent magnet holes. The bridge members are inserted into the rotor core in a heated and expanded state, for example. Patent Document 1 states that the inclusion of such bridges improves the mechanical strength of the rotor core. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Application Laid-Open No. 2009-201269 Summary of the Invention [Problem to be solved by the invention]

[0004] Incidentally, the bridge member in Patent Document 1 is inserted into the rotor core in a heated and expanded state, and therefore its shape and dimensions are set to correspond to the shape and dimensions of the fitting hole. If press fitting or shrink fitting is used to insert such a bridge member into the fitting hole, the rotor core may be deformed or residual stress may occur in the rotor core. As a result, the strength of the rotor core may be reduced.

[0005] Therefore, an object of the present invention is to provide a rotor core that can suppress deformation of the rotor core and the occurrence of residual stress in the rotor core when a bridge member that is provided separately from the rotor core is assembled to the rotor core. [Means for solving the problem]

[0006] The above objective can be achieved by a rotor core having a plurality of magnet insertion sections and a magnet insertion hole into which a bridge member formed of a non-magnetic material is inserted, the bridge insertion sections being arranged at positions that divide the magnet insertion hole into a plurality of regions each including the magnet insertion sections, and into which the bridge members are inserted, and a resin section being provided in the part of the magnet insertion hole excluding the magnet insertion sections and the bridge insertion sections. [Effects of the Invention]

[0007] A rotor core can be provided that can suppress deformation of the rotor core and the occurrence of residual stress in the rotor core when a bridge member that is provided separately from the rotor core is assembled to the rotor core. [Brief explanation of the drawings]

[0008] [Figure 1] FIG. 1 is an explanatory diagram of a rotor equipped with a rotor core according to an embodiment. [Figure 2] FIG. 2 is an enlarged view of one magnetic pole formed on the rotor in the embodiment. [Figure 3] FIG. 3 is an enlarged view showing a schematic exploded view of the X portion in FIG. DETAILED DESCRIPTION OF THE INVENTION

[0009] (Embodiment) The rotor 1 shown in FIG. 1 includes a rotor core 10, and first and second permanent magnets 21 and 22 embedded in the rotor core 10. The rotor 1 forms a rotating electric machine together with a stator (not shown) consisting of three phases: U, V, and W. The rotating electric machine formed by the rotor 1 is a permanent magnet synchronous rotating electric machine, a so-called IPM (Interior Permanent Magnet) motor. A rotating shaft (not shown) is fixed to the center of the rotor 1. The rotor 1 of this embodiment forms an 8-pole, 24-slot motor. However, the type of motor is not limited to this, and various types known in the art can be adopted.

[0010] The rotor 1 is formed with an even number of magnetic poles 2 (eight in FIG. 1) that are arranged at equal intervals in the circumferential direction across the q axis. The polarities of the even number of magnetic poles 2 are alternately reversed in the circumferential direction. The rotor core 10 is provided with a magnet insertion hole 11 in each magnetic pole 2. Referring to FIG. 2, each magnetic pole 2 has a structure that is symmetrical in the circumferential direction across the d axis. The circumferential center of the magnet insertion hole 11 coincides with the d axis. The magnet insertion hole 11 has a shape that is symmetrical in the circumferential direction with respect to the d axis.

[0011] The magnet insertion hole 11 has a first region 11a on one circumferential side with respect to the d axis. The magnet insertion hole 11 has a bridge insertion portion 11b in the region where the d axis passes, and the magnet insertion hole 11 has a second region 11c on the other circumferential side with respect to the d axis. A resin portion 30 is provided in the magnet insertion hole 11. The resin portion 30 will be described in detail later.

[0012] The first region 11a includes a first magnet insertion portion 11a1. A first permanent magnet 21 is inserted into the first magnet insertion portion 11a1. The first region 11a includes a first air hole 11a2 on a side closer to the bridge insertion portion 11b than the first magnet insertion portion 11a1, i.e., closer to the d-axis. The first air hole 11a2 is filled with a resin material. The first region 11a includes a second air hole 11a3 on a side farther from the bridge insertion portion 11b than the first magnet insertion portion 11a1, i.e., closer to the q-axis. The second air hole 11a3 is filled with a resin material. The resin material filled into the first air hole 11a2 and the second air hole 11a3 is, for example, a thermoplastic resin, and any conventionally known resin material can be used. The first air hole 11a2 and the second air hole 11a3 form part of the resin portion 30. For ease of understanding, the resin portion 30 is hatched in each drawing.

[0013] The bridge insertion portion 11b is formed in an area through which the d-axis passes. The bridge insertion portion 11b is provided so that its longitudinal direction coincides with the radial direction of the rotor core 10. A bridge member 25 as shown in FIG. 3 is inserted into the bridge insertion portion 11b. The bridge member 25 connects the inner and outer circumferential sides of the magnet insertion holes 11 in the rotor core 10.

[0014] The bridge member 25 is made of a non-magnetic material. When assembled to the rotor core 10, the bridge member 25 has a main body portion 25a that extends radially. The bridge member 25 has a first tapered portion 25b at one end and a second tapered portion 25c at the other end. The first tapered portion 25b and the second tapered portion 25c have smaller dimensions on the side closer to the main body portion 25a and larger dimensions toward the outside. The bridge insertion portion 11b has a shape corresponding to the shapes of the first tapered portion 25b and the second tapered portion 25c. In other words, the magnet insertion hole 11 has engaging portions 11b1 on the radially outer and inner sides of the rotor core 10, respectively. The first tapered portion 25b and the second tapered portion 25c are disposed within the engaging portions 11b1. The area around the bridge member 25 is filled with a resin material, similar to the first air hole 11a2 and the second air hole 11a3. The resin material forms the resin portion 30. As a result, centrifugal force, that is, a force in the radial direction of the rotor core 10, acts on the bridge member 25. Note that the bridge member 25 may have other shapes instead of the first tapered portion 25b and the second tapered portion 25c.

[0015] The second region 11c includes a second magnet insertion portion 11c1. A second permanent magnet 22 is inserted into the second magnet insertion portion 11c1. The second region 11c includes a third air hole 11c2 on a side closer to the bridge insertion portion 11b than the second magnet insertion portion 11c1, i.e., on the side closer to the d-axis. The third air hole 11c2 is filled with a resin material. The second region 11c includes a fourth air hole 11c3 on a side farther from the bridge insertion portion 11b than the second magnet insertion portion 11c1, i.e., on the side closer to the q-axis. The fourth air hole 11c3 is filled with a resin material. The third air hole 11c2 and the fourth air hole 11c3 form part of the resin portion 30, similar to the first air hole 11a2 and the second air hole 11a3.

[0016] The resin portion 30 is provided inside the magnet insertion hole 11. The resin portion 30 is provided in the portion of the magnet insertion hole 11 excluding the first magnet insertion portion 11a1, the second magnet insertion portion 11c1, and the bridge insertion portion 11b. As a result, the portion of the rotor 1 other than the first permanent magnet 21, the second permanent magnet 22, and the bridge member 25 becomes the resin portion 30. The resin portion 30 also extends between the inner circumferential wall surface 111 of the magnet insertion hole 11 and the first permanent magnet 21. The resin portion 30 also extends between the inner circumferential wall surface 111 of the magnet insertion hole 11 and the second permanent magnet 22. The resin portion 30 also extends between the inner circumferential wall surface 111 of the magnet insertion hole 11 and the bridge member 25. As a result, the first permanent magnet 21, the second permanent magnet 22, and the bridge member 25 are fixed inside the magnet insertion hole 11 by the resin portion 30. The resin portion 30 forms an insulating layer.

[0017] The bridge member 25 can improve the strength of the rotor 1, thereby increasing the rotation speed of the rotor 1. The bridge member 25 is made of a non-magnetic material, which can prevent short circuits of magnetic flux. As a result, the rotor 1 can be rotated efficiently, increasing the rotation speed of the rotor 1, and making the rotor 1 more compact.

[0018] In the rotor 1 of this embodiment, the bridge member 25 is fixed and assembled to the rotor core 10 by hardening the resin material. If shrink fitting or press fitting were used to assemble the bridge member 25 to the rotor core 10, the rotor core 10 could be deformed or residual stress could be generated in the rotor core 10. In contrast, resin materials can be applied at a much lower temperature range than shrink fitting or other methods, and do not require processing that involves overheating or deformation of components. This makes it possible to prevent the rotor core 10 from being deformed or from generating residual stress. This improves the strength of the rotor 1. Furthermore, the resin portion 30 also improves the strength of the rotor 1. The improved strength of the rotor 1 allows the rotor 1 to have an increased rotational speed.

[0019] Fixing with a resin material is also advantageous in terms of cost compared to shrink fitting or press fitting.

[0020] [Effect] In the rotor core 10 of the embodiment, the resin portion 30 is provided in the magnet insertion hole 11 in a portion excluding the magnet insertion portions 11a1, 11c1 and the bridge insertion portion 11b. The resin portion 30 secures the bridge member 25 disposed in the magnet insertion hole 11. The resin portion 30 can secure the bridge member 25 without performing processing that involves overheating or deformation of the member. This makes it possible to suppress deformation and the occurrence of residual stress when the bridge member 25 is assembled to the rotor core 10.

[0021] Although the embodiments of the present invention have been described in detail above, the present invention is not limited to such specific embodiments, and various modifications and variations are possible within the scope of the gist of the present invention as defined in the claims. [Explanation of symbols]

[0022] REFERENCE SIGNS LIST 1...rotor, 2...magnetic pole, 10...rotor core, 11...magnet insertion hole, 11a...first region, 11a1...first magnet insertion section, 11a2...first air hole, 11a3...second air hole, 11b...bridge insertion section, 11c...second region, 11c1...second magnet insertion section, 11c2...third air hole, 11c3...fourth air hole, 21...first permanent magnet, 22...second permanent magnet, 25...bridge member, 25a...main body section, 25a...first tapered section, 25b...second tapered section, 30...resin section, 111...inner peripheral wall surface

Claims

[Claim 1] A rotor core having a plurality of magnet insertion portions and magnet insertion holes into which bridge members formed of a non-magnetic material are inserted, a bridge insertion portion into which the bridge member is inserted, the bridge insertion portion being provided at a position that divides the magnet insertion hole into a plurality of regions each including the magnet insertion portion; a resin portion is provided in a portion of the magnet insertion hole excluding the magnet insertion portion and the bridge insertion portion; Rotor core.

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