motor

Abstract

The motor includes a cylindrical rotor core and a magnet assembly comprising first and second magnets alternately arranged along the circumference of the rotor core. First magnetic lines of force generated within the first magnets extend radially along the rotor core, while second magnetic lines of force generated within the second magnets are inclined relative to the first magnetic lines of force. The rotor core includes an inner portion located radially inward of the magnet assembly and an outer portion located radially outward of the magnet assembly. The outer portion includes a first core that radially covers the first magnets and a second core that radially covers at least a portion of the rotor core's central axis.

Description

Technical Field

[0001] The present invention relates to motors. Background Art

[0002] Among conventional synchronous multiphase AC motors, which are rotating electrical machines, there are motors that have a cylindrical rotor and a stator arranged concentrically with the rotor on the inside of the rotor (for example, see Patent Document 1). Patent Document 1 describes a motor in which a plurality of permanent magnets are arranged circumferentially along the inner periphery of the rotor. Furthermore, the plurality of permanent magnets are configured using a magnet arrangement known as a "Halbach array." Specifically, the plurality of permanent magnets include a first magnet with a radial magnetization direction and a second magnet with a circumferential magnetization direction, with the first and second magnets being arranged alternately along the circumferential direction.

[0003] Prior art literature

[0004] Patent Literature

[0005] Patent Document 1: Japanese Patent Application Publication No. 2019-024294 Summary of the Invention

[0006] Problems to be solved by the invention

[0007] In the motor described in Patent Document 1, magnetic saturation occurs in the magnet holding portion, thereby generating leakage magnetic flux. This has the problem of reducing the output of the motor due to the leakage magnetic flux.

[0008] An object of the present invention is to provide a motor capable of increasing the output of the motor.

[0009] Means for solving problems

[0010] One embodiment of the present invention is a motor, characterized in that the motor comprises: a rotor core, which is cylindrical; and a magnet group, which has a first magnet and a second magnet alternately arranged along the circumferential direction of the rotor core, the first magnetic lines of force generated in the first magnet are along the radial direction of the rotor core, and the second magnetic lines of force generated in the second magnet are inclined relative to the first magnetic lines of force, the rotor core comprises: an inner portion, which is located radially inward of the magnet group; and an outer portion, which is located radially outward of the magnet group, the outer portion comprising: a first core, which covers the first magnet from the radial outside; and a second core, which covers at least a portion of the rotor core's central axis direction of the second magnet from the radial outside.

[0011] Effects of the Invention

[0012] According to one embodiment of the motor of the present invention, the output can be increased. BRIEF DESCRIPTION OF THE DRAWINGS

[0013] Figure 1 This is a schematic partial cross-sectional view showing an embodiment of a motor according to the present invention.

[0014] Figure 2 yes Figure 1 An enlarged perspective view of the motor is shown.

[0015] Figure 3 yes Figure 1 An enlarged perspective view of the rotor of the motor shown. DETAILED DESCRIPTION

[0016] Reference Figures 1 to 3 Embodiments of the motor of the present invention will be described.

[0017] Figure 1 The motor 1 shown is a motor mounted on a vehicle such as an automobile and used. The motor 1 includes a rotor 11 and a stator 9 .

[0018] like Figure 2 As shown, the stator 9 includes a cylindrical core back 91 and a plurality of teeth (protrusions) 92 provided on the inner circumference of the core back 91. The plurality of teeth 92 protrude radially toward the central axis O1 of the motor 1. A conductive coil (not shown) is wound around each tooth 92.

[0019] like Figure 1 As shown, a rotor 11 is arranged inside the stator 9 concentrically with the stator 9. The rotor 11 is supported so as to be rotatable about the central axis O1 of the motor 1. The rotor 11 includes a rotor core 2 and a magnet group 8.

[0020] The rotor core 2 is cylindrical in shape as a whole.

[0021] The magnet group 8 includes first magnets 81 and second magnets 82 that are alternately arranged at intervals along the circumferential direction of the rotor core 2. Both the first magnets 81 and the second magnets 82 are permanent magnets, and the same number of the first magnets 81 and the second magnets 82 are arranged.

[0022] like Figure 2 、 Figure 3 As shown, the rotor core 2 includes an inner portion 3 located radially inward (on the central axis O1 side) of the magnet group 8 , an outer portion 4 located radially outward of the magnet group 8 , and a connecting portion 5 connecting the inner portion 3 and the outer portion 4 .

[0023] The inner portion 3 has a cylindrical shape.

[0024] The outer portion 4 is provided along the circumferential direction of the inner portion 3. The outer portion 4 is arranged radially outward relative to the first magnet 81 and the second magnet 82. This reduces eddy current loss.

[0025] The connecting portion 5 is provided between the inner portion 3 and the outer portion 4. Thus, when manufacturing the rotor core 2, the inner portion 3, the outer portion 4, and the connecting portion 5 can be integrally molded using a mold. This allows for easy and rapid manufacturing of the rotor core 2. Multiple connecting portions 5 are arranged along the circumference of the inner portion 3. This ensures stable and secure connection between the inner portion 3 and the outer portion 4.

[0026] Furthermore, the inner portion 3, outer portion 4, and connecting portion 5 are not limited to being integrally molded. For example, when manufacturing the rotor core 2, a T-shaped magnetic body formed by integrating the second core 42 (described later) with the connecting portion 5 may be inserted between the second magnets 82. In this case, the second magnets 82 and the second core 42 are preferably fixed with an adhesive or the like.

[0027] There are no particular limitations on the material constituting the rotor core 2. The rotor core 2 is, for example, made of a magnetic material. Examples of the magnetic material constituting the magnetic material (soft magnetic material) include electromagnetic steel (silicon steel), carbon steel, structural steel, pure iron, soft iron, stainless permalloy, and the like.

[0028] A magnet group 8 is held between the inner portion 3 and the outer portion 4. As described above, the magnet group 8 includes a plurality of first magnets 81 and a plurality of second magnets 82 arranged alternately along the circumference of the rotor core 2. Each first magnet 81 and each second magnet 82 is in the form of an elongated strip, that is, a rod or plate, extending in the direction of the central axis O1.

[0029] like Figure 1 、 Figure 2 As shown, first magnetic lines of force ML1 are generated within each first magnet 81. Each first magnetic line of force ML1 extends radially along the rotor core 2. In particular, in this embodiment, the first magnetic line of force ML1 of one of the circumferentially adjacent first magnets 81 sandwiching the second magnet 82 is directed inwardly of the rotor core 2, that is, toward the center axis O1, through the first magnetic line of force ML1A. The first magnetic line of force ML1 of the other first magnet 81 is directed outwardly of the rotor core 2, that is, away from the center axis O1, through the first magnetic line of force ML1B.

[0030] Second magnetic lines of force ML2 are generated in each second magnet 82. Each second magnetic line of force ML2 is inclined relative to an imaginary line VL (first magnetic line of force ML1) connecting the center of the second magnet 82 and the center axis O1. In particular, in this embodiment, the second magnet 82 is divided into two small magnets in such a way that the second magnetic lines of force ML2 are oriented in different directions. Hereinafter, one of the two small magnets will be referred to as the "first split magnet (first small magnet) 821", and the other small magnet will be referred to as the "second split magnet (second small magnet) 822". The connecting portion 5 is located between the first split magnet 821 and the second split magnet 822.

[0031] The second magnetic lines of force ML2 of the first segmented magnet (first small magnet) 821 are second magnetic lines of force ML2A directed toward the inside of the rotor core 2. The second magnetic lines of force ML2 of the second segmented magnet 822 are second magnetic lines of force ML2B directed toward the outside of the rotor core 2. Furthermore, both the second magnetic lines of force ML2A and ML2B are inclined relative to the imaginary line VL. The inclination angle θ2A of the second magnetic lines of force ML2A and the inclination angle θ2B of the second magnetic lines of force ML2B relative to the imaginary line VL are preferably greater than 0 degrees and less than 90 degrees, and more preferably greater than 25 degrees and less than 65 degrees.

[0032] like Figure 3 As shown, the outer portion 4 includes a first core 41 and a second core 42 .

[0033] The first core 41 is disposed facing the first magnet 81. The first core 41 has a plate shape extending along the central axis O1 and covers the entire outer surface (front surface) 813 of the first magnet 81 from the radially outer side.

[0034] The second core 42 is arranged facing both the second magnets 82, namely the first split magnet 821 and the second split magnet 822. The second core 42 has a plate-like shape extending along the circumference of the rotor core 2, and covers at least a portion of the outer surface (front surface) 823 of the second magnet 82 from the radially outer side in the direction of the central axis O1 (the central axis of the rotor core 2). In this embodiment, two second cores 42 are arranged for each second magnet 82, spaced apart from each other in the direction of the central axis O1.

[0035] The outer portion 4 of this structure attracts magnetic flux to the first and second cores 41, 42, which are made of the aforementioned material (magnetic substance) with relatively high magnetic permeability. This reduces magnetic flux leakage (hereinafter referred to as the "magnetic flux reduction effect"). Furthermore, this magnetic flux leakage reduction effect, in conjunction with the aforementioned orientation of the magnetic flux lines, can improve the output of the motor 1.

[0036] In particular, in this embodiment, as described above, two second cores 42 are disposed for each second magnet 82, and each second core 42 partially covers the outer surface 823 of the second magnet 82. This improves the leakage flux reduction effect.

[0037] The radial thickness t82 of the second magnet 82 is thicker than the radial thickness t81 of the first magnet 81. This allows the thickness t42 of the second core 42 to be thinner than the thickness t41 of the first core 41, allowing the rotor core 2 (outer portion 4) to be formed into a cylindrical shape. This allows the rotor core 2 to rotate stably. In the second core 42 with a thinner thickness t42, the magnetic flux remaining in the second core 42 can be reduced.

[0038] The motor of the present invention has been described above based on the illustrated embodiment, but the present invention is not limited thereto, and the components constituting the motor can be replaced with components of any structure capable of performing the same function. In addition, any structure can be added.

[0039] Description of labels

[0040] 1: Motor; 2: Rotor core; 3: Inner portion; 4: Outer portion; 41: First core; 42: Second core; 5: Connecting portion; 8: Magnet assembly; 81: First magnet; 813: Outer surface (front surface); 82: Second magnet; 821: First split magnet (first small magnet); 822: Second split magnet (second small magnet); 823: Outer surface (front surface); 9: Stator; 91: Core Back; 92: Teeth (protrusions); 11: Rotor; ML1: 1st magnetic line of force; ML1A: 1st magnetic line of force; ML1B: 1st magnetic line of force; ML2: 2nd magnetic line of force; ML2A: 2nd magnetic line of force; ML2B: 2nd magnetic line of force; O1: Center axis; t41: Thickness; t42: Thickness; t81: Thickness; t82: Thickness; VL: Imaginary line; θ2A: Tilt angle; θ2B: Tilt angle.

Claims

1. A motor, characterized in that: The motor has: a rotor core having a cylindrical shape; and a magnet group including first magnets and second magnets alternately arranged along the circumferential direction of the rotor core; The first magnetic lines of force generated in the first magnet are along the radial direction of the rotor core. The second magnetic force lines generated in the second magnet are inclined relative to the first magnetic force lines. The rotor core has: an inner portion located radially inward of the magnet group; and an outer portion located radially outward of the magnet group, The outer portion has: a first iron core covering the first magnet from the radially outer side; and a second core covering at least a portion of the rotor core in the direction of the central axis line of the second magnet from the radially outer side; A plurality of the second cores are arranged at intervals from each other in the direction of the central axis.

2. The motor according to claim 1, wherein The thickness of the second magnet along the radial direction is thicker than the thickness of the first magnet along the radial direction.

3. The motor according to claim 2, wherein: The thickness of the second core along the radial direction is thinner than the thickness of the first core along the radial direction.

4. The motor according to any one of claims 1 to 3, characterized in that At least a portion of the second core is made of a magnetic material.

5. The motor according to any one of claims 1 to 3, characterized in that The rotor core includes a connecting portion connecting the inner portion and the outer portion.

6. The motor according to any one of claims 1 to 3, characterized in that Among the first magnets adjacent to each other in the circumferential direction via the second magnet, the first magnetic force lines of one first magnet are directed toward the inside of the rotor core, and the first magnetic force lines of the other first magnet are directed toward the outside of the rotor core.

7. The motor according to any one of claims 1 to 3, characterized in that The second magnet is divided into two parts so that the second magnetic lines of force are directed in different directions.

8. The motor according to claim 7, characterized in that The second magnetic force lines of one of the two second magnets are directed toward the inner side of the rotor core, and the second magnetic force lines of the other magnet are directed toward the outer side of the rotor core.

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