Rotating electric machine

Abstract

The objective is to improve the fixing strength of the magnets on the rotor surface. [Solution] The rotating electric machine comprises a stator and a rotor disposed radially inward of the stator with a gap between them, the rotor comprising a rotor core and a plurality of magnets fixed to the outer circumferential surface of the rotor core, each of the plurality of magnets having a fitting portion that fits with an adjacent magnet among the plurality of magnets, and each of the plurality of magnets being restricted from moving radially outward by the fitting.

Description

[[Technical Field]]

[0001] The present invention relates to a rotating electrical machine. [[Background Art]]

[0002] For shapes such as in-wheel motors in which a sufficient back yoke cannot be secured for the rotor core, a configuration is known in which magnets are adhered to the outer circumferential surface of the rotor core with an adhesive in a Halbach array. However, when the magnets are merely adhered with adhesive, there is a possibility that the magnets may fall off or scatter due to aging deterioration of the adhesive or other factors.

[0003] In response to this, Patent Document 1 discloses a structure in which a molded resin member formed by filling a resin material into gaps between magnets attached to the surface of the rotor core and grooves on the surface of the rotor core provided correspondingly to the gaps is arranged. [[Prior Art Documents]] [[Patent Documents]]

[0004] [[Patent Document 1]] Japanese Unexamined Patent Publication No. 9-19091 [[Summary of the Invention]] [[Problem to be Solved by the Invention]]

[0005] However, in the structure disclosed in Patent Document 1, since the magnets are fixed by the molded resin member, the fixing strength of the magnets depends on the strength of the molded resin member, and there is a problem that the strength cannot be ensured. In addition, since the molded resin member is interposed between the magnets, there is a problem that the amount of magnets is reduced and the electrical characteristics are degraded. Furthermore, dimensional changes of the molded resin member caused by temperature rise of the rotor create gaps between the magnets and the molded resin member, resulting in a decrease in the fixing strength of the magnets. For this reason, there has conventionally been room for improvement in the fixing strength of magnets on the rotor surface.

[0006] The present invention has been made in view of the above points, and aims to improve the fixing strength of the magnets on the rotor surface. [Means for solving the problem]

[0007] A rotating electric machine according to one aspect of the present invention comprises a stator and a rotor disposed radially inward of the stator with a gap between them, wherein the rotor comprises a rotor core and a plurality of magnets fixed to the outer circumferential surface of the rotor core, each of the plurality of magnets having a fitting portion that fits with an adjacent magnet among the plurality of magnets, and each of the plurality of magnets is restricted from moving radially outward by the fitting. [Effects of the Invention]

[0008] According to one aspect of the present invention, the fixing strength of the magnets on the rotor surface can be improved. [Brief explanation of the drawing]

[0009] [Figure 1] This is a cross-sectional view of a motor 100 according to Embodiment 1 of the present invention. [Figure 2] This is a magnified view of the vicinity of magnets 320 and 330. [Modes for carrying out the invention]

[0010] The following description of a rotating electric machine according to an embodiment of the present invention will be made with reference to the drawings. Note that in the following drawings, the scale and number of components in each structure may differ from the actual structure in order to make the components easier to understand.

[0011] <Embodiment 1> Figure 1 is a cross-sectional view of a motor 100 according to Embodiment 1 of the present invention. The motor 100 is a radial gap motor and is an example of a rotating electric machine. The motor 100 rotates around its central axis J as the axis of rotation.

[0012] Furthermore, in the drawings, the XYZ coordinate system is shown as a three-dimensional Cartesian coordinate system where appropriate. In the XYZ coordinate system, the Z-axis direction is parallel to the axis direction of the central axis J shown in Figure 1. The Y-axis direction is the vertical direction in Figure 1, which is the radial direction with respect to the central axis J. The X-axis direction is perpendicular to both the Y-axis and Z-axis directions. In all of the X-axis, Y-axis, and Z-axis directions, the side pointed to by the arrow shown in the figure is the + side, and the opposite side is the - side. In each embodiment of the present invention, the Y-axis direction is assumed to be the direction of gravity.

[0013] Furthermore, in the following explanation, the positive side in the Z-axis direction (+Z side) will be referred to as "one side," and the negative side in the Z-axis direction (-Z side) will be referred to as "the other side." Note that "one side" and "the other side" are merely names used for explanatory purposes and do not limit the actual positional relationship or direction. Unless otherwise specified, the direction parallel to the central axis J (Z-axis direction) will be simply referred to as the "axis direction," the radial direction centered on the central axis J will be simply referred to as the "radial direction," and the circumferential direction centered on the central axis J, i.e., around the axis of the central axis J, will be simply referred to as the "circumferential direction." In the radial direction, the side approaching the central axis J will be referred to as the "inside radial direction," and the side moving away from the central axis J will be referred to as the "outside radial direction." In the circumferential direction, the clockwise side when viewed from the +Z side to the -Z side will be referred to as the "one side circumferential," and the counterclockwise side will be referred to as the "other side circumferential."

[0014] In this specification, "extending in the axial direction" includes not only cases where the material extends strictly in the axial direction, but also cases where the material extends in a direction inclined to the axial direction by an angle of less than 45°. Furthermore, in this specification, "extending radially" includes not only cases where the material extends strictly radially, i.e., perpendicular to the axial direction, but also cases where the material extends in a direction inclined to the radial direction by an angle of less than 45°. Furthermore, "parallel" includes not only cases where the material is strictly parallel, but also cases where the angle between the material and the material is inclined to each other by an angle of less than 45°. Furthermore, "spreading in a direction perpendicular to the axial direction" includes not only cases where the material spreads in a direction perpendicular to the axial direction, but also cases where the material spreads in a direction inclined to the direction perpendicular to the axial direction by an angle of less than 45°.

[0015] The motor 100 has a stator 200 and a rotor 300 arranged radially inward of the stator 200 with a gap between them. In this embodiment, parts other than the essential parts of the present invention are not shown and described.

[0016] The stator 200 has a cylindrical stator core 210 and stator coils 230. The stator core 210 has multiple teeth 220 that protrude radially inward and are arranged circumferentially. The stator coils 230 are wound around the teeth 220. The rotor 300 has a cylindrical rotor core 310 and magnets 320 and 330 arranged on the outer circumferential surface of the rotor core 310.

[0017] Figure 2 is a magnified view of the vicinity of magnets 320 and 330. Multiple magnets 320 and 330 are arranged in a Halbach array on the outer circumferential surface of the rotor core 310. In Figure 2, the direction indicated by the arrow is the magnetization direction.

[0018] The magnet 320 has a protrusion 320a at one end in the circumferential direction, which protrudes radially towards the center and radially towards the one end in the circumferential direction, more so than radially outward and radially inward. The magnet 320 also has a protrusion 320b at the other end in the circumferential direction, which protrudes radially towards the other end in the circumferential direction, more so than radially outward and radially inward.

[0019] On the other hand, the magnet 330 has a recess 330a at one end in the circumferential direction, where the radially central side is recessed toward the other end in the circumferential direction more than the radially outer and radially inner sides. The magnet 330 also has a recess 330b at the other end in the circumferential direction, where the radially central side is recessed toward the one end in the circumferential direction more than the radially outer and radially inner sides.

[0020] The protruding portion 320a and the recessed portion 330b are shaped to fit into each other, and the protruding portion 320b and the recessed portion 330a are shaped to fit into each other. The protruding portion 320a of the magnet 320 fits into the recessed portion 330b of the adjacent magnet 330 on one circumferential side thereof. The protruding portion 320b of the magnet 320 fits into the recessed portion 330a of the adjacent magnet 330 on the other circumferential side thereof. The protruding portion 320a, the protruding portion 320b, the recessed portion 330a and the recessed portion 330b are an example of fitting portions that fit with adjacent magnets.

[0021] By fitting the protruding portion 320a with the recessed portion 330b and fitting the protruding portion 320b with the recessed portion 330a, movement of the magnet 320 outward in the radial direction is restricted by the magnet 330, and movement of the magnet 330 outward in the radial direction is restricted by the magnet 320.

[0022] When attaching the magnets 320 and 330 to the outer circumferential surface of the rotor core 310, the magnets 320 and 330 are alternately attached sequentially to the outer circumferential surface of the rotor core 310 with an adhesive while fitting the protruding portion 320a with the recessed portion 330b and fitting the protruding portion 320b with the recessed portion 330a in the circumferential direction. For the last one of the magnets 320 or 330 in the circumferential direction, all of the magnets 320 and 330 are attached to the outer circumferential surface of the rotor core 310 by inserting it from the axial direction. The magnets 320 and 330 are bonded to the outer circumferential surface of the rotor core 310 with an adhesive, thereby preventing circumferential displacement relative to the outer circumferential surface of the rotor core 310.

[0023] According to the present embodiment, by fitting the magnet 320 and the magnet 330 together, mutual movement outward in the radial direction can be restricted. Therefore, even if the adhesive bonding force between the rotor core 310 and the magnets 320 and 330 is lost, scattering of the magnets 320 and 330 due to centrifugal force or the like can be avoided. Further, according to the present embodiment, compared to the conventional case where the magnets are fixed by a molded resin member, strength can be ensured without depending on the strength of the molded resin member.

[0024] Furthermore, according to this embodiment, since no molded resin member is interposed between the magnets, the amount of magnets is not reduced, and the electrical properties are not degraded. Also, according to this embodiment, since no molded resin member is interposed between the magnets, there is no dimensional change due to the temperature rise of the rotor, no gaps are created between the magnets, and the fixing strength of the magnets can be maintained.

[0025] In the above-described embodiment, the magnet arrangement was a Halbach arrangement, but the present invention is not limited to this and can also be applied to a normal surface magnet type rotor composed of magnets whose magnetization direction is only in the radial direction.

[0026] Furthermore, in the above-described embodiment, protrusions 320a and 320b are provided on one circumferential end and the other circumferential end of the magnet 320, and recesses 330a and 330b are provided on one circumferential end and the other circumferential end of the magnet 330, but the present invention is not limited thereto. For example, the magnets 320 and 330 may be fitted together by providing a protrusion on one circumferential end and a recess on the other circumferential end of the magnet 320, and a protrusion on one circumferential end and a recess on the other circumferential end of the magnet 330. The shape of the fitting portion between the magnets 320 and 330 may be any shape as long as it restricts their movement outward in the radial direction.

[0027] The present invention is not limited to the embodiments described above, and various improvements and design modifications may be made without departing from the spirit of the invention. In addition, the embodiments disclosed herein should be considered in all respects to be illustrative and not restrictive. The scope of the present invention is indicated by the claims rather than by the above description, and all modifications within the meaning and scope equivalent to the claims are intended to be included. [Explanation of symbols]

[0028] 100...motor 200...Stata 300... Rotor

Claims

1. stator and, A rotor is positioned radially inward of the stator with a gap between them, It has, The rotor comprises a rotor core and a plurality of magnets fixed to the outer circumferential surface of the rotor core. Each of the plurality of magnets has a fitting portion that fits with an adjacent magnet among the plurality of magnets, Each of the aforementioned magnets is restricted from moving radially outward by the fitting. A rotating electric machine characterized by the following features.

2. Each of the aforementioned plurality of magnets is fixed to the outer surface of the rotor core by being bonded with an adhesive. The rotating electric machine according to feature 1.

3. The fitting portion consists of a convex portion that protrudes circumferentially towards the radial center more than the radially outer and radially inner portions, and a concave portion that is recessed circumferentially towards the radial center more than the radially outer and radially inner portions. The rotating electric machine according to feature 1.

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