Outer rotor type motor and manufacturing method for the same

Abstract

To provide an outer rotor type motor capable of miniaturizing a magnetizing device for magnetizing permanent magnets.SOLUTION: The outer rotor type motor includes a stator 2 and a rotor 3 provided radially outwardly in a direction D2 with respect to the stator 2. The rotor 3 includes a rotor yoke 301 extending radially outwardly in the direction D2 from a rotation axis 1, a plurality of divided cores 302 provided on the rotor yoke 301 and arranged in a circumferential direction D3, and a plurality of permanent magnets 303 provided one each on the plurality of divided cores 302.SELECTED DRAWING: Figure 1

Description

Technical Field

[0001] This invention relates to an outer rotor type motor and a method for manufacturing the same.

Background Art

[0002] Conventionally, an outer rotor type motor including a stator and a rotor provided on the radially outer side of the stator is known. The rotor has a rotor yoke extending radially outward from a rotating shaft, a cylindrical rotor core provided on the rotor yoke, and a plurality of permanent magnets provided on the rotor core and arranged in the circumferential direction. The rotor core is formed with a plurality of magnet insertion holes into which each of the plurality of permanent magnets is inserted one by one (see, for example, Patent Document 1).

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] Each permanent magnet is magnetized in a state where each permanent magnet before magnetization is inserted into each magnet insertion hole. However, in the configuration of the outer rotor type motor described in Patent Document 1, when the dimensions of the rotor in the radial direction are large, there is a problem that the magnetizing device for magnetizing the permanent magnet becomes large-sized.

[0005] This invention has been made to solve the above-described problems, and an object thereof is to provide an outer rotor type motor and a method for manufacturing the same that can reduce the size of the magnetizing device for magnetizing a permanent magnet.

Means for Solving the Problems

[0006] The outer-rotor type motor according to the present invention includes a stator and a rotor provided radially outside the stator. The rotor includes a rotor yoke extending radially outward from the rotation axis, a plurality of divided cores provided on the rotor yoke and arranged side by side in the circumferential direction, and a plurality of permanent magnets provided one by one on each of the plurality of divided cores. In the outer-rotor type motor according to the present invention, a magnet insertion hole into which a corresponding permanent magnet among the plurality of permanent magnets is inserted is formed in each of the plurality of divided cores. In the outer-rotor type motor according to the present invention, the plurality of divided cores are composed of two types of divided cores. A concave portion recessed inward in the circumferential direction is formed on the circumferential side surface of a first divided core, which is one type of the two types of divided cores. A convex portion protruding outward in the circumferential direction is formed on the circumferential side surface of a second divided core, which is the other type of the two types of divided cores. The first divided core and the second divided core are arranged adjacent to each other in the circumferential direction, and the convex portion is inserted into the concave portion in the adjacent first divided core and second divided core. In the outer-rotor type motor according to the present invention, the directions of the magnetic fields of the permanent magnets provided in the first divided core and the permanent magnets provided in the second divided core are opposite to each other in the radial direction. In the outer-rotor type motor according to the present invention, the plurality of divided cores are formed in the same shape as each other. A concave portion recessed inward in the circumferential direction is formed on one side surface in the circumferential direction of each of the plurality of divided cores. A convex portion (310) protruding outward in the circumferential direction is formed on the other side surface in the circumferential direction of each of the plurality of divided cores. In a pair of adjacent divided cores among the plurality of divided cores, the convex portion of one divided core is inserted into the concave portion of the other divided core. The manufacturing method of the outer rotor type motor according to the present invention includes a step of attaching a permanent magnet before magnetization to each of a plurality of divided cores one by one, a magnetization step of magnetizing each of the permanent magnets before magnetization after the step of attaching the permanent magnet before magnetization, and a step of attaching the plurality of divided cores side by side in the circumferential direction to a rotor yoke after the magnetization step.

Effect of the Invention

[0007] According to the outer rotor type motor and its manufacturing method according to the present invention, it is possible to miniaturize a magnetization device for magnetizing a permanent magnet.

Brief Description of the Drawings

[0008]

Figure 1

Figure 2

Figure 3

Figure 4

Figure 5

Figure 6

Figure 7

Figure 8

Figure 9

Figure 10

Modes for Carrying Out the Invention

[0009] Embodiment 1. FIG. 1 is a cross-sectional view showing an outer rotor type motor according to Embodiment 1. The outer rotor type motor includes a rotating shaft 1, a stator 2, a rotor 3, and a bearing 4.

[0010] The shape of the rotating shaft 1 is cylindrical. The direction along the axis of the rotating shaft 1 is defined as the axial direction D1. The direction along the radius of the circle centered on the axis of the rotating shaft 1 in a plane orthogonal to the axis of the rotating shaft 1 is defined as the radial direction D2. The direction along the circumference of the circle centered on the axis of the rotating shaft 1 in a plane orthogonal to the axis of the rotating shaft 1 is defined as the circumferential direction D3.

[0011] The stator 2 is provided outside the rotating shaft 1 in the radial direction D2. The stator 2 is arranged away from the outer peripheral surface of the rotating shaft 1. The rotating shaft 1 is rotatable with respect to the stator 2.

[0012] The stator 2 includes a stator yoke 21, a stator core (not shown), and a plurality of coils (not shown). The shape of the stator yoke 21 is cylindrical. The stator yoke 21 is arranged coaxially with the axis of the rotating shaft 1. The diameter of the inner peripheral surface of the stator yoke 21 is larger than the diameter of the outer peripheral surface of the rotating shaft 1. The stator core is provided on the stator yoke 21. The plurality of coils are provided on the stator core. The plurality of coils are arranged in a row in the circumferential direction D3. A current is supplied to the plurality of coils from a power supply device (not shown).

[0013] The rotor 3 is provided outside the stator 2 in the radial direction D2. The rotor 3 includes a rotor yoke 301, a plurality of divided cores 302, and a plurality of permanent magnets 303.

[0014] The rotor yoke 301 is arranged to extend radially outward from the rotary shaft 1 in the radial direction D2. The rotor yoke 301 is fixed to the rotary shaft 1 via a plurality of fasteners 304. Examples of the fasteners 304 include screws. By fixing the rotor yoke 301 to the rotary shaft 1, the rotor yoke 301 rotates in the circumferential direction D3 together with the rotary shaft 1.

[0015] FIG. 2 is a perspective view showing the rotor yoke 301 of FIG. 1. FIG. 3 is a partial cross-sectional view showing the rotor yoke 301 of FIG. 2. The rotor yoke 301 includes a rotor yoke body 305 and a protrusion 306. The shape of the rotor yoke body 305 is disc-shaped. The stator yoke 21 is attached to the rotor yoke body 305 via a bearing 4. The rotor yoke body 305 is arranged coaxially with the axis of the rotary shaft 1.

[0016] The protrusion 306 is provided on the outer peripheral portion of the rotor yoke body 305. The protrusion 306 is formed to protrude from the outer peripheral portion of the rotor yoke body 305 to one side in the axial direction D1. The shape of the protrusion 306 is cylindrical. The protrusion 306 is arranged coaxially with the axis of the rotary shaft 1.

[0017] A plurality of split cores 302 are provided on the rotor yoke 301. The plurality of split cores 302 are arranged in a row in the circumferential direction D3. Each split core 302 is made of a magnetic material. One magnet insertion hole 307 is formed in each split core 302. The magnet insertion hole 307 is arranged to extend along the axial direction D1. The magnet insertion hole 307 is arranged such that one side in the axial direction D1 is open.

[0018] The plurality of permanent magnets 303 are provided one by one on the plurality of divided cores 302. The plurality of permanent magnets 303 are inserted one by one into the magnet insertion holes 307 of the corresponding divided cores 302 among the plurality of divided cores 302. In other words, one magnet insertion hole 307 into which the corresponding permanent magnet 303 among the plurality of permanent magnets 303 is inserted is formed in each divided core 302. Therefore, the outer rotor type motor according to Embodiment 1 is an IPM (Interior Permanent Magnet) type motor.

[0019] The bearing 4 is provided between the stator yoke 21 of the stator 2 and the rotor yoke 301 of the rotor 3. Therefore, the rotor 3 is rotatably supported by the stator 2 via the bearing 4.

[0020] FIG. 4 is a perspective view showing the first divided core of FIG. 1. FIG. 5 is a partial cross-sectional view showing the first divided core of FIG. 4. FIG. 6 is a perspective view showing the second divided core of FIG. 1. FIG. 7 is a partial cross-sectional view showing the second divided core of FIG. 6. The plurality of divided cores 302 are composed of two types of divided cores 302. One type of the two types of divided cores 302 is defined as the first divided core 302a. The other type of the two types of divided cores 302 is defined as the second divided core 302b.

[0021] The shape of the first divided core 302a is the shape of a divided piece when a cylindrical member is evenly divided in the circumferential direction. Concave portions 308 that are recessed inward in the circumferential direction D3 are formed on both side surfaces in the circumferential direction D3 of the first divided core 302a. The concave portions 308 are arranged to extend along the axial direction D1.

[0022] A groove 309 is formed on the side surface on the other side in the axial direction D1 of the first divided core 302a. The groove 309 of the first divided core 302a is arranged to extend along the circumferential direction D3.

[0023] The shape of the second split core 302b is the shape of a split piece when a cylindrical member is evenly split in the circumferential direction. On both side surfaces in the circumferential direction D3 of the second split core 302b, convex portions 310 protruding outward in the circumferential direction D3 are formed. The convex portions 310 are arranged so as to extend along the axial direction D1.

[0024] A groove 309 is formed on the other side surface in the axial direction D1 of the second split core 302b. The groove 309 of the second split core 302b is arranged so as to extend along the circumferential direction D3.

[0025] FIG. 8 is a perspective view showing the rotor yoke 301, the plurality of split cores 302, and the plurality of permanent magnets 303 of FIG. 1. FIG. 9 is a plan view showing the rotor yoke 301, the plurality of split cores 302, and the plurality of permanent magnets 303 of FIG. 8.

[0026] The plurality of first split cores 302a and the plurality of second split cores 302b are alternately arranged one by one in a row in the circumferential direction D3. Therefore, the first split cores 302a and the second split cores 302b are arranged adjacent to each other in the circumferential direction D3. In the first split core 302a and the second split core 302b adjacent to each other, the convex portion 310 is inserted into the concave portion 308.

[0027] By inserting the convex portion 310 into the concave portion 308 in the first split core 302a and the second split core 302b adjacent to each other, the first split core 302a and the second split core 302b adjacent to each other are fixed to each other.

[0028] The protruding portion 306 of the rotor yoke 301 is inserted into the groove 309 of the first split core 302a. By inserting the protruding portion 306 of the rotor yoke 301 into the groove 309 of the first split core 302a, the first split core 302a is fixed to the rotor yoke 301.

[0029] The protrusion 306 of the rotor yoke 301 is inserted into the groove 309 of the second split core 302b. By inserting the protrusion 306 of the rotor yoke 301 into the groove 309 of the second split core 302b, the second split core 302b is fixed to the rotor yoke 301.

[0030] The directions of the magnetic fields of the permanent magnets 303 provided in the first split core 302a and the permanent magnets 303 provided in the second split core 302b are opposite to each other in the radial direction D2.

[0031] Next, a method for manufacturing the outer rotor type motor according to Embodiment 1 will be described. Specifically, a method for manufacturing the rotor 3 of the outer rotor type motor will be described. FIG. 10 is a flowchart showing the method for manufacturing the outer rotor type motor according to Embodiment 1.

[0032] In the manufacturing process of the outer rotor type motor, first, in step S101, a pre-magnetization permanent magnet mounting process is performed. In the pre-magnetization permanent magnet mounting process, a pre-magnetization permanent magnet 303 is mounted on each of the plurality of split cores 302 one by one.

[0033] Thereafter, in step S102, a magnetization process is performed. The magnetization process is performed after the pre-magnetization permanent magnet mounting process. In the magnetization process, each of the pre-magnetization permanent magnets 303 is magnetized. At this time, each permanent magnet 303 is magnetized. As a result, compared with the case where all the permanent magnets 303 are magnetized simultaneously, the magnetization device for magnetizing the permanent magnets 303 can be miniaturized.

[0034] Thereafter, in step S103, a split core mounting process is performed. The split core mounting process is performed after the magnetization process. In the split core mounting process, a plurality of split cores 302 are arranged in a row in the circumferential direction D3 and attached to the rotor yoke 301. At this time, the plurality of split cores 302 are arranged such that the first split core 302a and the second split core 302b are adjacent to each other in the circumferential direction D3, and in the first split core 302a and the second split core 302b adjacent to each other, the convex portion 310 is inserted into the concave portion 308. Further, the protruding portion 306 of the rotor yoke 301 is inserted into the groove 309 of the first split core 302a and the groove 309 of the second split core 302b. Thus, the manufacturing process of the outer rotor type motor is completed.

[0035] As described above, the outer rotor type motor according to Embodiment 1 includes a stator 2 and a rotor 3 provided outside the stator 2 in the radial direction D2. The rotor 3 includes a rotor yoke 301 extending outward in the radial direction D2 from the rotating shaft 1, a plurality of split cores 302 provided on the rotor yoke 301 and arranged side by side in the circumferential direction D3, and a plurality of permanent magnets 303 provided one by one on each of the plurality of split cores 302. According to this configuration, the permanent magnet 303 can be magnetized in a state where the permanent magnet 303 is inserted into the split core 302 and before the split core 302 is attached to the rotor yoke 301. Thereby, even when the dimension of the rotor 3 in the radial direction D2 is large, the magnetizing device for magnetizing the permanent magnet 303 can be made small. As a result, the magnetizing device for magnetizing the permanent magnet 303 can be miniaturized.

[0036] Further, in the outer rotor type motor according to Embodiment 1, a magnet insertion hole 307 into which a corresponding permanent magnet 303 among the plurality of permanent magnets 303 is inserted is formed in each of the plurality of split cores 302. According to this configuration, the permanent magnet 303 can be attached to the split core 302 by inserting the permanent magnet 303 into the magnet insertion hole 307. Thereby, the permanent magnet 303 can be easily attached to the split core 302.

[0037] Further, in the outer rotor type motor according to Embodiment 1, the plurality of divided cores 302 are composed of two types of divided cores 302. On the side surface in the circumferential direction D3 of the first divided core 302a, which is one type of the two types of divided cores 302, a recess 308 that is recessed inward in the circumferential direction D3 is formed. On the side surface in the circumferential direction D3 of the second divided core 302b, which is the other type of the two types of divided cores 302, a convex portion 310 that protrudes outward in the circumferential direction D3 is formed. The first divided core 302a and the second divided core 302b are arranged adjacent to each other in the circumferential direction D3. In the first divided core 302a and the second divided core 302b that are adjacent to each other, the convex portion 310 is inserted into the recess 308. According to this configuration, by inserting the convex portion 310 into the recess 308 in the first divided core 302a and the second divided core 302b that are adjacent to each other in the circumferential direction D3, the first divided core 302a and the second divided core 302b that are adjacent to each other can be attached to each other. Thereby, the first divided core 302a and the second divided core 302b that are adjacent to each other in the circumferential direction D3 can be easily attached to each other.

[0038] Further, in the outer rotor type motor according to Embodiment 1, the directions of the magnetic fields of the permanent magnets 303 provided in the first divided core 302a and the permanent magnets 303 provided in the second divided core 302b are opposite to each other in the radial direction D2. According to this configuration, by arranging the plurality of divided cores 302 such that the first divided core 302a and the second divided core 302b are adjacent to each other in the circumferential direction D3, the directions of the magnetic fields of the permanent magnets 303 that are adjacent to each other in the circumferential direction D3 can be made opposite to each other in the radial direction D2.

[0039] In addition, the manufacturing method of the outer-rotor type motor according to Embodiment 1 includes a pre-magnetization permanent magnet mounting step, a magnetization step performed after the pre-magnetization permanent magnet mounting step, and a split core mounting step performed after the magnetization step. In the pre-magnetization permanent magnet mounting step, one pre-magnetization permanent magnet 303 is provided for each of the plurality of split cores 302. In the magnetization step, each of the pre-magnetization permanent magnets 303 is magnetized. In the split core mounting step, the plurality of split cores 302 are arranged in the circumferential direction D3 and attached to the rotor yoke 301. According to this configuration, the permanent magnet 303 can be magnetized in a state where the permanent magnet 303 is inserted into the split core 302 and before the split core 302 is attached to the rotor yoke 301. As a result, even when the dimension of the rotor 3 in the radial direction D2 is large, the magnetization device for magnetizing the permanent magnet 303 can be made smaller. As a result, the magnetization device for magnetizing the permanent magnet 303 can be miniaturized.

[0040] In the outer-rotor type motor according to Embodiment 1, the configuration in which the recesses 308 are formed on both side surfaces in the circumferential direction D3 of the first split core 302a and the protrusions 310 are formed on both side surfaces in the circumferential direction D3 of the second split core 302b has been described. However, the present invention is not limited to this configuration. For example, the plurality of split cores 302 may be formed in the same shape as each other, the recesses 308 may be formed on one side surface in the circumferential direction D3 of each split core 302, and the protrusions 310 may be formed on the other side surface of each split core 302. In a pair of adjacent split cores 302 in the circumferential direction D3 of the plurality of split cores 302, the protrusions 310 of one split core 302 are inserted into the recesses 308 of the other split core 302, whereby the adjacent split cores 302 can be attached to each other.

[0041] The outer-rotor type motor and its manufacturing method according to the preferred Embodiment 1 have been described above, but the outer-rotor type motor and its manufacturing method according to the above-described Embodiment 1 are not limited thereto. Various modifications and conversions can be made to the outer-rotor type motor and its manufacturing method according to the above-described Embodiment 1 without departing from the scope described in the claims.

Description of Reference Numerals

[0042] 1 Rotating shaft, 2 Stator, 3 Rotor, 4 Bearing, 21 Stator yoke, 301 Rotor yoke, 302 Split core, 302a First split core, 302b Second split core, 303 Permanent magnet, 304 Fastener, 305 Rotor yoke body, 306 Protrusion, 307 Magnet insertion hole, 308 Recess, 309 Groove, 310 Protrusion.

Claims

1. A stator (2), a rotor (3) provided radially outside the stator (2), and comprising: the rotor (3) includes: a rotor yoke (301) extending radially outward from the rotating shaft (1), a plurality of divided cores (302) provided on the rotor yoke (301) and arranged side by side in the circumferential direction, and a plurality of permanent magnets (303) each provided on one of the plurality of divided cores (302), an outer rotor type motor.

2. The outer rotor type motor according to claim 1, wherein each of the plurality of divided cores (302) is formed with a magnet insertion hole (307) into which a corresponding permanent magnet (303) of the plurality of permanent magnets (303) is inserted.

3. The plurality of divided cores (302) are composed of two types of divided cores (302). On the circumferential side surface of a first divided core (302a), which is one type of the two types of divided cores (302), a recess (308) recessed inward in the circumferential direction is formed. On the circumferential side surface of a second divided core (302b), which is the other type of the two types of divided cores (302), a convex portion (310) protruding outward in the circumferential direction is formed. The first divided core (302a) and the second divided core (302b) are arranged adjacent to each other in the circumferential direction. The outer rotor type motor according to claim 1 or claim 2, wherein in the first divided core (302a) and the second divided core (302b) adjacent to each other, the convex portion (310) is inserted into the recess (308).

4. The outer rotor type motor according to claim 3, wherein the magnetic field directions of the permanent magnets (303) provided on the first divided core (302a) and the permanent magnets (303) provided on the second divided core (302b) are opposite to each other in the radial direction.

5. The plurality of divided cores (302) are formed in the same shape as each other. On one surface in the circumferential direction of each of the plurality of divided cores (302), a recess (308) recessed inward in the circumferential direction is formed. On the other surface in the circumferential direction of each of the plurality of divided cores (302), a convex portion (310) protruding outward in the circumferential direction is formed. The outer rotor type motor according to claim 1 or claim 2, wherein in a pair of adjacent divided cores among the plurality of divided cores (302), the convex portion (310) of one divided core is inserted into the concave portion (308) of the other divided core.

6. A method for manufacturing an outer rotor type motor according to claim 1 or claim 2, comprising: a step of attaching a permanent magnet (303) before magnetization to each of the plurality of divided cores (302), one by one; a magnetization step of magnetizing each of the permanent magnets (303) before magnetization after the step of attaching the permanent magnet before magnetization; a divided core attachment step of arranging the plurality of divided cores (302) in the circumferential direction and attaching them to the rotor yoke (301) after the magnetization step; A method for manufacturing an outer rotor type motor comprising the above steps.

Images