Rotor and electric motor

Abstract

Provided is a rotor that is stable in magnetic properties and can be manufactured inexpensively. The rotor of an embodiment is a rotor provided in an electric motor, opposes a stator, and rotates about a rotational axis. The rotor has first magnets and second magnets alternately arranged in a circumferential direction. One of the first magnets and the second magnets is a main magnet, and the other is an auxiliary magnet. The main magnet is magnetically oriented in a radial direction. The auxiliary magnet is magnetically oriented in the circumferential direction. The first magnet has a pair of first circumferential end surfaces. The pair of first circumferential end surfaces respectively face both sides in the circumferential direction. The second magnet has a pair of second circumferential end surfaces. The pair of second circumferential end surfaces respectively face both sides in the circumferential direction. The second circumferential end surfaces are in surface contact with the first circumferential end surfaces of the first magnets adjacent thereto. The pair of second circumferential end surfaces of one second magnet are parallel to each other.

Description

Technical Field

[0001] Embodiments of the present invention relate to rotors and electric motors. Background Technology

[0002] It is known that electric motors increase drive torque by arranging rotor magnets in a Hale-Beck array. In such rotors, the positional accuracy of the magnets significantly affects the rotor's magnetic characteristics. However, existing technologies suffer from difficulties in improving the positional accuracy of the magnets and in stabilizing the rotor's magnetic characteristics.

[0003] Prior technical documents:

[0004] Patent documents:

[0005] Patent Document 1: International Publication No. 2013 / 008284 Summary of the Invention

[0006] The problem to be solved by this invention is to provide a rotor and an electric motor with stable magnetic properties that can be manufactured inexpensively.

[0007] In this embodiment, the rotor is mounted on the motor, opposite the stator, and rotates about a rotation axis. The rotor includes first and second magnets arranged alternately in a circumferential direction. One of the first and second magnets is a main magnet, and the other is an auxiliary magnet. The main magnet is magnetically oriented radially. The auxiliary magnet is magnetically oriented circumferentially. The first magnet has a pair of first circumferential end faces, each facing one of the two circumferential sides. The second magnet has a pair of second circumferential end faces, each facing one of the two circumferential sides. The second circumferential end faces are in contact with the first circumferential end faces of adjacent first magnets. The pair of second circumferential end faces of one second magnet are parallel to each other. Attached Figure Description

[0008] Figure 1 This is a cross-sectional view of a washing machine with an electric motor according to one embodiment.

[0009] Figure 2 This is a cross-sectional perspective view of the rotor and stator according to one embodiment.

[0010] Figure 3 This is a partial cross-sectional schematic diagram of the peripheral wall portion of a rotor according to one embodiment.

[0011] Figure 4 This is a cross-sectional view of the rotor along the axial direction of one embodiment.

[0012] Figure 5 This is a schematic diagram illustrating a same-pole excitation process in one embodiment.

[0013] Figure 6 This is a schematic diagram illustrating a different pole excitation process in one embodiment.

[0014] Explanation of reference numerals in the attached figures:

[0015] 3…recess, 16…motor, 20…rotor, 30…stator, 70…retaining part, 80…main magnet, 81…first opposing surface, 83…first circumferential end face, 90…auxiliary magnet, 91…second opposing surface, 93…second circumferential end face, 95…upper end face (axial end face), 96…first chamfer, 97…second chamfer, C…circumferential, d…depth (radial dimension), O…rotation shaft, R…radial, R1…stator side, W1, W2…thickness dimension Detailed Implementation

[0016] Hereinafter, the rotor, motor, and rotor manufacturing method of the embodiments will be described with reference to the accompanying drawings. In the following description, structures with the same or similar functions will be labeled with the same reference numerals. Furthermore, repeated descriptions of these structures will sometimes be omitted.

[0017] Figure 1 This is a cross-sectional view of a washing machine having the electric motor of this embodiment.

[0018] In the following description, the side facing the washing machine, i.e., the vertically lower side, is defined as the lower side of the washing machine, and the side opposite the facing side, i.e., the vertically upper side, is defined as the upper side of the washing machine. Furthermore, left and right are defined based on the direction from which the washing machine is viewed from the front of the user. The side closer to the user standing in front of the washing machine when viewed from the front is defined as "front," and the side farther away is defined as "rear." In this specification, "horizontal width direction" means the left-right direction as defined above. In this specification, "depth direction" means the front-back direction as defined above. In the diagram, +X direction is the right direction, -X direction is the left direction, +Y direction is the rear direction, -Y direction is the front direction, +Z direction is the up direction, and -Z direction is the down direction.

[0019] Figure 1 This is a cross-sectional view of washing machine 1 perpendicular to the front-to-back direction.

[0020] Washing machine 1, for example, includes a frame 11, a top cover 12, a water tank 13, a rotating drum 14, a pulsator 15, and a motor 16. Washing machine 1 is a so-called vertical axis type washing machine in which the rotation axis O of the rotating drum 14 faces the vertical direction. However, washing machine 1 is not limited to the vertical axis type, and can also be a horizontal axis type, i.e., a so-called front-loading washing machine, in which the rotation axis of the rotating drum faces the horizontal direction or tilts downwards to the rear.

[0021] The frame 11 is constructed as a single rectangular box, for example, from a steel plate. The top cover 12 is made of synthetic resin, for example, and is located on the upper part of the frame 11. The water tank 13 and the rotating drum 14 function as washing and spin-drying drums for holding the clothes to be washed. The water tank 13 and the rotating drum 14 are located inside the frame 11. The water tank 13 and the rotating drum 14 are configured as containers with open upper surfaces. Water in the water tank 13 flows out from the drain outlet 131 and is drained to the outside via the drain valve 132.

[0022] The electric motor 16 is located on the lower side of the water tank 13. The electric motor 16 is connected to the rotating drum 14 and the impeller 15 via a clutch mechanism 17. The rotation shaft O of the electric motor 16 is aligned with the center of the water tank 13.

[0023] The electric motor 16 in this embodiment is an external rotor type. The electric motor 16 has an annular stator 30 arranged around a rotation axis O and a rotor 20 that surrounds the stator 30 radially outward. That is, the electric motor 16 is provided with a stator 30 and a rotor 20. The stator 30 is fixed to the frame 11 of the washing machine 1. Furthermore, the rotor 20 rotates around the rotation axis O.

[0024] The rotor 20 is a bottomed cylindrical shape having a peripheral wall portion 22 and a bottom wall portion 21. The peripheral wall portion 22 is cylindrical with the rotation axis O as its center. The peripheral wall portion 22 is radially opposed to the stator 30. That is, the rotor 20 is radially opposed to the stator 30. The bottom wall portion 21 extends radially inward from the lower end of the peripheral wall portion 22. The bottom wall portion 21 is circular plate-shaped along a plane orthogonal to the rotation axis O. The rotor 20 is connected to the clutch mechanism 17 at the bottom wall portion 21.

[0025] The clutch mechanism 17 selectively transmits the rotation of the motor 16 to the drum 14 and the impeller 15. During washing and rinsing, the clutch mechanism 17 transmits the driving force of the motor 16 to the impeller 15, driving the impeller 15 to rotate directly in both directions at a low speed. On the other hand, during spin-drying and other processes, the clutch mechanism 17 transmits the driving force of the motor 16 to the drum 14, driving the drum 14 to rotate at high speed in one direction.

[0026] Figure 2 This is a cross-sectional perspective view of the rotor 20 and the stator 30. Additionally, in Figure 2 The illustration of the holding part 70, which will be described later, is omitted. Additionally, in... Figure 2 The schematic map shows the shape of the magnet.

[0027] Figure 3 This is a partial cross-sectional schematic diagram of the peripheral wall portion 22 of the rotor 20. Figure 3 It is a cross-sectional view along a section orthogonal to the axis of rotation O.

[0028] In the following description, the direction in which the stator 30 is configured (in this embodiment, radially inner) relative to the rotor 20 is referred to as the stator side R1, and the direction in the radial direction opposite to the stator 30 (in this embodiment, radially outer) is referred to as the anti-stator side R2.

[0029] like Figure 2 As shown, the stator 30 has a stator core 31, a coil 39, and an insulator (not shown). The stator core 31 has an annular core back 32 centered on the rotation axis O, and a plurality of teeth 33 extending radially outward from the core back 32. The plurality of teeth 33 are arranged circumferentially C. The coil 39 is formed by winding a conductor around the teeth 33 through the insulator.

[0030] The rotor 20 has multiple main magnets (first magnets) 80, multiple auxiliary magnets (second magnets) 90, a frame 60, and a retaining part 70 for fixing them together. Figure 2 The middle part is omitted; please refer to the following: Figure 3 ).

[0031] like Figure 2 As shown, the frame 60 has a disc portion 61 and a cylindrical portion 62. The disc portion 61 is disc-shaped with the rotation axis O as its center. The disc portion 61 forms the bottom wall portion 21 of the rotor 20. The cylindrical portion 62 extends upward from the outer edge of the disc portion 61. The cylindrical portion 62 is cylindrical with the rotation axis O as its center. A plurality of main magnets 80 and a plurality of auxiliary magnets 90 are arranged circumferentially C along the inner surface of the cylindrical portion 62.

[0032] The main magnet 80 and the auxiliary magnet 90 extend in a columnar shape along the axial direction of the rotation axis O with the same cross section. The upper surfaces of the main magnet 80 and the auxiliary magnet 90 are substantially the same plane. Similarly, the lower surfaces of the main magnet 80 and the auxiliary magnet 90 are substantially the same plane. The lower surfaces of the main magnet 80 and the auxiliary magnet 90 are opposite to and in contact with the upper surface of the disk portion 61 of the frame 60.

[0033] In this embodiment, the main magnet 80 and the auxiliary magnet 90 are ferrite magnets. However, the main magnet 80 and the auxiliary magnet 90 can also be other types of magnets (e.g., neodymium magnets).

[0034] like Figure 3 As shown, the main magnet 80 and the auxiliary magnet 90 are alternately arranged along the circumferential direction C. The main magnet 80 and the auxiliary magnet 90 are magnetically oriented along the radial direction R and the circumferential direction C, respectively. That is, the main magnet 80 and the auxiliary magnet 90 are arranged in a Hellbeck array. Furthermore, in Figure 3 In the diagram, the arrows on each magnet indicate its magnetic orientation.

[0035] The main magnet 80 is a magnet with its magnetic orientation along the radial direction R. That is, the main magnet 80 uses the radial direction R as the direction of its internal magnetic flux. The magnetic poles of the multiple main magnets 80 arranged along the circumferential direction C are alternately reversed. Therefore, the magnetic poles (N pole or S pole) of adjacent main magnets 80 in the circumferential direction C are different from each other.

[0036] The main magnet 80 has a first opposing surface 81 facing the stator side R1 and opposite to the stator 30, a first opposing surface 82 facing the anti-stator side R2, and a pair of first circumferential end surfaces 83 facing the circumferential sides respectively. The thickness of the main magnet 80 along the radial direction R is the largest at the center of the circumference and decreases as it faces the circumferential sides.

[0037] The first opposing surface 81 is a flat surface orthogonal to the radial direction. The first opposing surface 81 can also be a gently curved surface with a fixed distance from the rotation axis O.

[0038] The first opposing surface 82 is a gently curved surface with a fixed distance from the rotation axis O. The first opposing surface 82 can also be a flat surface orthogonal to the radial direction. The first opposing surface 82 is positioned opposite the cylindrical portion 62 of the frame 60 at a certain gap.

[0039] The first end face 83 is a flat surface. The pair of first end faces 83 are not parallel to each other. When viewed from the axial direction, the intersection point of the extensions of the pair of first end faces 83 is located radially inward relative to the main magnet 80. Therefore, the main magnet 80 is approximately fan-shaped.

[0040] The auxiliary magnet 90 is a magnet with its magnetic orientation along the circumferential direction C. That is, the auxiliary magnet 90 uses the circumferential direction C as the direction of its internal magnetic flux. The magnetic poles of the multiple auxiliary magnets 90 arranged along the circumferential direction C are alternately reversed. Therefore, the magnetic poles (N pole or S pole) of adjacent auxiliary magnets 90 along the circumferential direction C are different from each other.

[0041] The auxiliary magnet 90 has a second opposing surface 91 facing the stator side R1 and opposite to the stator 30, a second opposing surface 92 facing the anti-stator side R2, and a pair of second circumferential end surfaces 93 facing the circumferential sides respectively.

[0042] In a cross-section orthogonal to the rotation axis O, the auxiliary magnet 90 of this embodiment is rectangular. The thickness of the auxiliary magnet 90 along the radial direction R is smaller than the thickness of the main magnet 80 along the radial direction R. Furthermore, the circumferential dimension C of the auxiliary magnet 90 is smaller than the circumferential dimension C of the main magnet 80. Additionally, for the purpose of ensuring the magnetic characteristics of the rotor 20, the ratio of the circumferential dimension C of the auxiliary magnet 90 to the circumferential dimension C of the main magnet 80 is preferably set to 1.8 to 2.2.

[0043] The second opposing surface 91 is a flat surface orthogonal to the radial direction. Similarly, the second opposing surface 92 is a flat surface orthogonal to the radial direction. Therefore, the second opposing surface 91 and the second opposing surface 92 are parallel to each other. In addition, the radial dimensions of the auxiliary magnet 90 are the same. The second opposing surface 91 is located on the anti-stator side R2 compared to the first opposing surface 81. Therefore, a recess 3 surrounded by the second opposing surface 91 and the two first peripheral end faces 83 is formed on the radially inner side of the auxiliary magnet 90. In addition, the radial position of the second opposing surface 92 is approximately the same as the radial position of the first opposing surface 82. The first opposing surface 82 and the second opposing surface 92 are respectively disposed in close contact with the cylindrical portion 62 of the frame 60.

[0044] The second end face 93 is a flat surface. The second end face 93 is opposite to the first end face 83 of the adjacent main magnet 80. The second end face 93 is in contact with the first end face 83 of the adjacent main magnet 80.

[0045] According to this embodiment, the first peripheral end face 83 of the main magnet 80 is in contact with the second peripheral end face 93 of the auxiliary magnet 90. Therefore, the magnetic resistance of the magnetic circuit through the boundary between the main magnet 80 and the auxiliary magnet 90 can be reduced, and the magnetic characteristics of the rotor 20 can be improved.

[0046] A pair of second peripheral end faces 93 of an auxiliary magnet 90 are parallel to each other. In this specification, "a pair of opposite faces are parallel" means not only that these faces are parallel in a strict sense and the angle between the faces is 0°, but also that the angle between the opposite faces is within ±1° of 0°.

[0047] Generally, magnets are formed by sintering and heat treatment, then their dimensional accuracy is improved by machining before being energized. Examples of machining methods include grinding by placing the magnetic components between two rotating grinding stones. Therefore, when two parallel surfaces facing opposite directions are parallel, the magnet's dimensional and geometric tolerances can be easily reduced through machining. Furthermore, when two parallel surfaces facing opposite directions are parallel, these surfaces can be machined using inexpensive methods, thus enabling the manufacture of magnets at a low cost.

[0048] According to this embodiment, the second circumferential end faces 93 of the auxiliary magnet 90 facing both sides in the circumferential direction are parallel to each other. Therefore, it is easy to improve the dimensional tolerances and geometric tolerances (more specifically, parallelism) of the auxiliary magnet 90. As a result, it is possible to make high-precision ground contact between the main magnet 80, which is arranged alternately in the circumferential direction, and the auxiliary magnet 90. In addition, according to this embodiment, the auxiliary magnet 90 can be manufactured inexpensively, and the cost of the motor 16 can be reduced.

[0049] Furthermore, in this embodiment, the second circumferential end faces 93 of the auxiliary magnet 90 are parallel to each other. However, the above-mentioned effect can be obtained as long as a pair of circumferential end faces of either the main magnet 80 or the auxiliary magnet 90 are parallel to each other. That is, when the rotor 20 has a first magnet and a second magnet arranged alternately in the circumferential direction, and one of them is a main magnet magnetically oriented in the radial direction while the other is an auxiliary magnet magnetically oriented in the circumferential direction, it is sufficient that a pair of circumferential end faces of one of the magnets (e.g., the second magnet) are parallel to each other.

[0050] Furthermore, in this embodiment, the circumferential dimension of the auxiliary magnet 90 is smaller than that of the main magnet 80. Regarding the machining of the two opposite faces, when these faces are not parallel, the closer the distance between the faces, the more difficult the machining becomes. In this embodiment, the circumferential dimension of the auxiliary magnet 90 is smaller. Therefore, by making the second circumferential end faces 93 of the auxiliary magnet 90 parallel to each other and the first circumferential end faces 83 of the main magnet 80 non-parallel, the rotor 20 can be manufactured as a whole at low cost.

[0051] According to this embodiment, the second opposing surface 91 of the auxiliary magnet 90 is located on the opposite side of the stator 30 compared to the first opposing surface 81 of the main magnet 80. Therefore, the auxiliary magnet 90 is disposed further away from the stator 30 than the main magnet 80. In the rotor 20 of the Helbeck array, if the auxiliary magnet 90 is close to the stator 30, demagnetization of the auxiliary magnet 90 easily becomes significant under the magnetic force of the stator 30 during operation. According to this embodiment, by moving the auxiliary magnet 90 away from the stator 30, demagnetization of the auxiliary magnet 90 can be suppressed.

[0052] The retaining part 70 is made of resin material. Multiple main magnets 80 and multiple auxiliary magnets 90 are embedded in the retaining part 70. Thus, the retaining part 70 retains the multiple main magnets 80 and the multiple auxiliary magnets 90.

[0053] The first opposing surface 81 of the main magnet 80 protrudes from the holding portion 70 toward the stator side R1. The main magnet 80 contacts the inner surface of the mold forming the holding portion 70 at the first opposing surface 81. In the case where multiple magnets (main magnet 80 and auxiliary magnet 90) are arranged in a Heilbeck array as in the rotor 20 of this embodiment, the positional accuracy of the main magnet 80 has a significant impact on the output performance of the motor 16. According to this embodiment, by making the main magnet 80 contact the inner surface of the mold forming the holding portion 70, the positional accuracy of the main magnet 80 after the holding portion 70 is formed can be improved, thereby improving the output performance of the motor 16. Moreover, according to this embodiment, the situation where the holding portion 70 obstructs the flow of magnetic flux between the first opposing surface 81 and the stator 30 can be suppressed, thereby improving the output performance of the motor 16.

[0054] The second opposing surface 91 of the auxiliary magnet 90 is embedded in the holding portion 70. A portion of the holding portion 70 is filled within the recess 3 surrounded by the second opposing surface 91 and the first peripheral end face 83. Here, the portion of the holding portion 70 filled within the recess 3 is referred to as the filling portion 71. According to this embodiment, the second opposing surface 91 of the auxiliary magnet 90 is embedded by the filling portion 71. As a result, the auxiliary magnet 90 is securely held by the holding portion 70, and movement of the auxiliary magnet 90 toward the stator side R1 is more reliably suppressed. Furthermore, since the second opposing surface 91 of the auxiliary magnet 90 is covered by the holding portion 70, the influence of the magnetic field from the stator 30 on the auxiliary magnet 90 can be reduced, and demagnetization of the auxiliary magnet 90 can be suppressed.

[0055] In this embodiment, the radial depth d (i.e., radial dimension) of the recess 3 is preferably 0.3 mm or more. Uncured resin material, which was formed during the molding of the retaining portion 70, flows in the recess 3. Preferably, a gap of 0.3 mm or more is provided during the flow of the uncured resin material. That is, according to this embodiment, by making the radial depth d of the recess 3 0.3 mm or more, the resin material can be sufficiently filled into the recess 3, and the retaining portion 70 can be stably held in place of the auxiliary magnet 90. Furthermore, the auxiliary magnet 90 can be moved away from the stator 30, and demagnetization of the auxiliary magnet 90 during the driving of the motor 16 can be suppressed. Additionally, by making the depth d of the recess 3 0.7 mm or more, the filling of the resin material is more reliable, and demagnetization of the auxiliary magnet 90 is suppressed more reliably, which is therefore more preferable.

[0056] In this embodiment, the radial depth d of the recess 3 is preferably less than 50% of the radial thickness W1 of the main magnet 80. By making the depth d of the recess 3 less than 50% of the thickness W1, the radial thickness of the auxiliary magnet 90 can be ensured to a certain extent, thereby ensuring the magnetic force of the auxiliary magnet 90.

[0057] In this embodiment, the radial thickness W2 of the auxiliary magnet 90 is preferably 70% or more of the radial thickness W1 of the main magnet 80 (W2 / W1 ≥ 0.7). If the thickness W2 of the auxiliary magnet 90 is less than 70% of the thickness W1 of the main magnet 80, there is a risk that the magnetic force of the auxiliary magnet 90 will become insufficient, leading to an extreme reduction in the torque of the motor 16. According to this embodiment, by making the thickness W2 of the auxiliary magnet 90 at least 70% of the thickness W1 of the main magnet 80, the torque of the motor 16 can be sufficiently ensured. Furthermore, by making the thickness W2 of the auxiliary magnet 90 at least 90% of the thickness W1 of the main magnet 80, the torque of the motor 16 can be further ensured, which is therefore more preferable.

[0058] Furthermore, in this specification, the radial thickness dimension of the magnet refers to the dimension of the thickest part in the radial direction. In this embodiment, the thickness dimension of the main magnet 80 becomes the largest at the circumferential center. Therefore, the radial thickness of the main magnet 80 at the circumferential center is the thickness dimension W1 of the main magnet 80 in this specification.

[0059] Figure 4 This is a cross-sectional view of the rotor 20 along the axial direction (vertical direction). Figure 4 The cross-section is passed through the auxiliary magnet 90. In addition, in the following description, "upper side" and "lower side" are sometimes referred to as "one side of the axis" and "the other side of the axis" respectively with respect to the rotation axis O.

[0060] The retaining part 70 has a location on the main magnet 80 ( Figure 4 (Not shown in the diagram) and the upper annular portion 72 on the upper side of the auxiliary magnet 90. The upper annular portion 72 is annular about the rotation axis O. The upper annular portion 72 is embedded in the upper end face of the main magnet 80 and the auxiliary magnet 90. The filling portion 71 extends downward from the upper annular portion 72.

[0061] A gate mark 70g is provided on the upper end face (the end face facing the axial side) 72 of the upper annular portion 72. The gate mark 70g is positioned directly above the auxiliary magnet 90. Therefore, in the mold (not shown) that forms the retaining portion 70, the gate for filling the mold with molten resin is positioned directly above the auxiliary magnet 90.

[0062] like Figure 4 As shown, the auxiliary magnet 90 has an upper end face (axial end face) 95 facing upward (axial side), a second opposing surface 91 facing the stator side R1, and a second opposing surface 92 facing the anti-stator side R2. Furthermore, a first chamfer 96 is provided at the corner of the upper end face 95 and the second opposing surface 91. Moreover, a second chamfer 97 is provided at the corner of the upper end face 95 and the second opposing surface 92. The first chamfer 96 and the second chamfer 97 are provided to suppress corner defects during the forming process (e.g., grinding process) of the auxiliary magnet 90.

[0063] In this embodiment, the first chamfer 96 is larger than the second chamfer 97. The first chamfer 96 is connected to the recess 3 on the stator side R1 of the second opposing surface 91. Therefore, by ensuring a larger first chamfer 96, the molten resin flowing from the gate into the mold can be smoothly guided into the recess 3.

[0064] Furthermore, in this embodiment, the gate mark 70g is arranged to overlap with the first chamfer 96 when viewed from the axial direction. Therefore, in this embodiment, the molten resin flowing in from the gate directly contacts the first chamfer 96 and flows into the recess 3, thereby further improving the resin filling rate in the recess 3.

[0065] Furthermore, according to this embodiment, by making the first chamfer 96 larger than the second chamfer 97, the molten resin flows more easily into the stator side R1 relative to the auxiliary magnet 90 than into the anti-stator side R2. As a result, the auxiliary magnet 90 is pressed against the anti-stator side R2 within the mold due to the injection pressure of the molten resin. Consequently, the distance between the auxiliary magnet 90 and the stator 30 can be reliably ensured, and demagnetization of the auxiliary magnet 90 can be suppressed.

[0066] Furthermore, according to this embodiment, by making the first chamfer 96 and the second chamfer 97 different in size, it is possible to suppress the situation where the orientation of the auxiliary magnet 90 is incorrectly assembled. That is, the first chamfer 96 and the second chamfer 97 function as markers to prevent misassembly.

[0067] Next, the manufacturing method of rotor 20 will be explained.

[0068] The manufacturing method of rotor 20 includes a resin molding process and an excitation process. In this embodiment, the resin molding process and the excitation process are performed in sequence.

[0069] The resin molding process involves housing the unenergized main magnet 80 and the unenergized auxiliary magnet 90 within a mold, filling the mold with molten resin, and then casting them into the mold. After the resin has cured, the rotor 20 is removed from the mold.

[0070] The excitation process is the process of energizing the main magnet 80 and the auxiliary magnet 90.

[0071] In the following description, the unexcited main magnet 80 is referred to as the first magnetic component 80A, and the unexcited auxiliary magnet 90 is referred to as the second magnetic component 90A.

[0072] The excitation process includes both same-pole excitation and opposite-pole excitation processes.

[0073] Figure 5 This is a schematic diagram illustrating the same-pole excitation process. Additionally, Figure 6 This is a schematic diagram illustrating the process of excitation by opposite poles.

[0074] The same-pole excitation process is a process of energizing the second magnetic component 90A to make its magnetic orientation circumferential C. The second magnetic component 90A is energized through the same-pole excitation process and becomes a permanent magnet (auxiliary magnet 90).

[0075] The opposite-pole excitation process is a process of energizing the first magnetic component 80A so that its magnetic orientation is radial R. The first magnetic component 80A is energized through the opposite-pole excitation process and becomes a permanent magnet (main magnet 80).

[0076] The same-pole excitation process and the opposite-pole excitation process are performed by the excitation device 4. The excitation device 4 has four excitation yokes (first excitation yoke 40A, second excitation yoke 40B, third excitation yoke 40C, and fourth excitation yoke 40D). The four excitation yokes are connected to an excitation power supply (not shown). In addition, the excitation device in this embodiment uses four excitation yokes. However, the excitation device may also have an excitation yoke that can simultaneously excite all first magnetic components 80A and all second magnetic components 90A.

[0077] The first excitation yoke 40A and the second excitation yoke 40B are arranged opposite each other in the radial direction R. The first excitation yoke 40A and the second excitation yoke 40B are arranged on both sides of the thickness direction of a first magnetic component 80A. The first excitation yoke 40A is arranged on the outer side of the radial direction R, and the second excitation yoke 40B is arranged on the inner side of the radial direction R.

[0078] The third excitation yoke 40C and the fourth excitation yoke 40D are arranged opposite each other in the radial direction R. The third excitation yoke 40C and the fourth excitation yoke 40D are arranged on both sides of the thickness direction of the adjacent first magnetic component 80A sandwiched between the first excitation yoke 40A and the second excitation yoke 40B. The third excitation yoke 40C is arranged on the outer side of the radial direction R, and the fourth excitation yoke 40D is arranged on the inner side of the radial direction R.

[0079] like Figure 5 As shown, in the same-pole excitation process, the opposing first excitation yoke 40A and second excitation yoke 40B generate magnetic fields with the same pole. Furthermore, the opposing third excitation yoke 40C and fourth excitation yoke 40D generate magnetic fields with the same pole. At this time, the magnetic fields generated by the third excitation yoke 40C and fourth excitation yoke 40D are opposite poles to the magnetic fields generated by the first excitation yoke 40A and second excitation yoke 40B. Through the same-pole excitation process, the second magnetic component 90A is energized in the circumferential direction C. Alternatively, when the second magnetic component 90A is energized in the opposite direction along the circumferential direction C, it is sufficient that the magnetic fields generated by the four excitation yokes 40A, 40B, 40C, and 40D have magnetic poles opposite to those described above.

[0080] like Figure 6As shown, in the opposite-pole excitation process, opposing first excitation yokes 40A and second excitation yokes 40B generate opposite-pole magnetic fields, thereby energizing the clamped first magnetic component 80A in one direction (relative excitation). Simultaneously, opposing third excitation yokes 40C and fourth excitation yokes 40D generate opposite-pole magnetic fields, thereby energizing the clamped first magnetic component 80A in another direction (relative excitation). At this time, the orientation of the magnetic field between the third excitation yoke 40C and the fourth excitation yoke 40D is opposite to the orientation of the magnetic field between the first excitation yoke 40A and the second excitation yoke 40B. In the opposite-pole excitation process, all first magnetic components 80A are sequentially energized.

[0081] In the excitation process, the same-pole excitation process and the opposite-pole excitation process are repeated alternately in this order. By completing the excitation process, the rotor 20 is completed. The manufactured rotor 20 is then combined with the separately manufactured stator 30.

[0082] According to the manufacturing method of the rotor 20 in this embodiment, neither the first magnetic component 80A nor the second magnetic component 90A is energized during the magnet housing process. Therefore, during the housing process, the first magnetic component 80A and the second magnetic component 90A can be arranged close to each other.

[0083] According to this embodiment, the main magnet 80 and the auxiliary magnet 90 are fixed by the holding part 70 during the resin molding process by resin casting. The holding part 70 prevents the main magnet 80 and the auxiliary magnet 90 from repelling each other and separating. Therefore, the degree of freedom in the arrangement of the main magnet 80 and the auxiliary magnet 90 can be increased. In this embodiment, the main magnet 80 and the auxiliary magnet 90 are arranged in a high-density configuration. As a result, the magnetic force of the rotor 20 is increased, and the torque of the motor 16 is increased.

[0084] According to the rotor 20 manufacturing method of this embodiment, the main magnet 80 is energized by relative energization. Therefore, the generation of leakage flux in the energization process (opposite pole energization process) of the main magnet 80 can be suppressed, and the energization rate of the main magnet 80 can be improved. Moreover, according to the rotor 20 manufacturing method of this embodiment, the opposite pole energization process is performed after the same pole energization process. Therefore, demagnetization of the main magnet 80 in the energization process of the auxiliary magnet 90 can be suppressed.

[0085] In this embodiment, an external rotor type motor 16 is described. However, the above configuration can also be used for an internal rotor type motor.

[0086] While several embodiments of the invention have been described, these embodiments are provided by way of example and are not intended to limit the scope of the invention. These embodiments can be implemented in various other ways, and various omissions, substitutions, and modifications can be made without departing from the spirit of the invention. These embodiments and their variations are included in the scope and spirit of the invention, as well as in the scope of the invention as described in the claims and its equivalents.

Claims

1. A rotor, disposed in an electric motor, opposite to the stator, and rotating about a rotating shaft, wherein, The rotor includes a first magnet and a second magnet arranged alternately in the circumferential direction, one of which is a main magnet magnetically oriented in the radial direction, and the other is an auxiliary magnet magnetically oriented in the circumferential direction. The first magnet has a pair of first circumferential end faces facing opposite circumferential directions. The second magnet has a pair of second circumferential end faces that face each other toward the circumferential sides and are in contact with the first circumferential end face of the adjacent first magnet. The pair of second peripheral end faces of one of the second magnets are parallel to each other. The first magnet has a first opposing surface facing the stator side. The second magnet has a second opposing surface facing the stator side. The second opposing surface is located on the opposite side of the stator compared to the first opposing surface. The rotor has a retaining portion made of resin material in which the first magnet and the second magnet are embedded. A portion of the retaining portion is filled within a recess surrounded by the second opposing surface and the first peripheral end surface. The second magnet has: The axial end face facing the axial side of the rotating shaft; The second opposing surface; as well as Opposite side, radially facing the opposite side of the stator The chamfer of the angle formed by the axial end face and the second opposing face is larger than the chamfer of the angle formed by the axial end face and the opposite face.

2. A rotor, disposed in an electric motor, opposite to the stator, and rotating about a rotating shaft, wherein, The rotor includes a first magnet and a second magnet arranged alternately in the circumferential direction, one of which is a main magnet magnetically oriented in the radial direction, and the other is an auxiliary magnet magnetically oriented in the circumferential direction. The first magnet has a pair of first circumferential end faces facing opposite circumferential directions. The second magnet has a pair of second circumferential end faces that face each other toward the circumferential sides and are in contact with the first circumferential end face of the adjacent first magnet. The pair of second peripheral end faces of one of the second magnets are parallel to each other. The pair of first peripheral end faces of the first magnet are not parallel. The first magnet has a first opposing surface facing the stator side. The second magnet has a second opposing surface facing the stator side. The second opposing surface is located on the opposite side of the stator compared to the first opposing surface. The rotor has a retaining portion made of resin material in which the first magnet and the second magnet are embedded. A portion of the retaining portion is filled within a recess surrounded by the second opposing surface and the first peripheral end surface. The first opposing surface is exposed from the retaining portion.

3. The rotor according to claim 1 or 2, wherein, The radial dimension of the recess is 0.3 mm or more.

4. The rotor according to claim 1 or 2, wherein, The first magnet is the main magnet, and the second magnet is the auxiliary magnet. The radial dimension of the recess surrounded by the second opposing surface and the first peripheral end surface is less than 50% of the radial thickness dimension of the first magnet.

5. The rotor according to claim 1 or 2, wherein, The first magnet is the main magnet, and the second magnet is the auxiliary magnet. The radial thickness of the second magnet is more than 70% of the radial thickness of the first magnet.

6. An electric motor, wherein, have: The rotor according to any one of claims 1 to 5; and The stator.

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