JP2023087340A - motor - Google Patents

Abstract

To improve output torque.SOLUTION: A motor has a rotor which comprises a yoke, a plurality of first magnets, and a plurality of second magnets. The yoke has a plurality of frames each having an outer circumferential part. Each of the plurality of first magnets is disposed in each of the plurality of frames. In a circumferential direction, each of the second magnets is located between two adjacent ones of the plurality of frames. In the circumferential direction, each of the second magnets has a portion larger than a width between the outer circumferential parts of the two frames.SELECTED DRAWING: Figure 2

Description

The present invention relates to motors.

A so-called Halbach array motor is known in which a plurality of magnets with different directions of magnetic flux are arranged on the surface of a rotor yoke. In a Halbach array motor, for example, a motor having an inner rotor structure, there is known a technique of embedding a magnet in a magnet holding member in order to prevent the magnet from popping out due to centrifugal force during rotation.

JP 2007-006545 A JP 2010-207067 A WO2014/115655

However, in the Halbach array motor, the amount of magnetic flux flowing from the magnet to the stator may decrease. In this case, the output torque of the motor is reduced.

An object of one aspect is to provide a motor capable of improving output torque.

In one aspect, a motor includes a rotor having a yoke, a plurality of first magnets, and a second magnet. The yoke includes a plurality of frames having an outer peripheral portion, the plurality of first magnets are arranged within the plurality of frames, and the second magnets are arranged adjacent to each other among the plurality of frames in the circumferential direction. Between two matching frames. The second magnet has a portion larger than the width between the outer peripheral portions of the two frames in the circumferential direction.

According to one aspect, the output torque can be improved.

FIG. 1 is a perspective view showing an example of a motor in an embodiment. FIG. FIG. 2 is a partial top view showing an example of the motor in the embodiment. FIG. 3 is an enlarged top view showing an example of the motor in the embodiment. FIG. 4 is an enlarged top view showing an example of a yoke in the embodiment; FIG. 5 is an enlarged top view showing an example of the rotor in the first modified example. FIG. 6 is an enlarged top view showing an example of the rotor in the second modified example. FIG. 7 is an enlarged top view showing an example of the rotor in the third modified example. FIG. 8 is an enlarged top view showing an example of a rotor in the fourth modified example.

Hereinafter, embodiments of the motor disclosed in the present application will be described in detail based on the drawings. Note that the dimensional relationship of each element in the drawings, the ratio of each element, and the like may differ from reality. Even between the drawings, there are cases where portions with different dimensional relationships and ratios are included. In each drawing, in some cases, a coordinate system whose axial direction is the direction in which the rotating shaft of the motor extends is illustrated for easier understanding of the description.

[Embodiment]
First, the motor in the embodiment will be described with reference to FIG. FIG. 1 is a perspective view showing an example of a motor in an embodiment. FIG. As shown in FIG. 1 , the motor 1 in the embodiment includes a stator 10 and a rotor 20. As shown in FIG. The motor 1 in the embodiment is, for example, a so-called flat motor whose length in the radial direction is greater than the length in the axial direction of the stator. Motor 1 is, for example, a frameless motor. The motor 1 transmits driving force to the outside, for example, through a rotating shaft (not shown).

As shown in FIG. 1 , stator 10 includes stator core 11 , insulator 12 , and coil 13 . The stator core 11 is formed by laminating a plurality of plate-like metal members such as soft magnetic steel plates such as silicon steel plates and electromagnetic steel plates in the axial direction. The insulator 12 is made of an insulator such as resin, for example. The coil 13 is wound around the stator core 11 via the insulator 12, for example.

As shown in FIGS. 1 and 2, the rotor 20 is arranged on the inner peripheral side of the stator 10 in the radial direction. That is, the motor 1 in the embodiment is, for example, an inner rotor type motor. FIG. 2 is a partial top view showing an example of the motor in the embodiment. FIG. 2 is a top view of the portion indicated by frame F1 in FIG. Note that the stator 10 may be illustrated in a simplified manner from FIG. 2 onward. For example, illustration of the insulator 12 is omitted in FIG.

As shown in FIGS. 1 and 2, the rotor 20 includes a yoke 30, a plurality of first magnets 41, and a plurality of second magnets . In the following description, when the first magnet 41 and the second magnet 42 are not distinguished from each other, they may be referred to as the magnet 40 in some cases.

The yoke 30 is a yoke made of iron, for example, and has an annular portion 36 and a frame 39 surrounding a hole 38 . As shown in FIG. 2 , the annular portion 36 extends in the circumferential direction, and the plurality of frames 39 are arranged, for example, at regular intervals in the circumferential direction. In an embodiment, for example twenty frames 39A to 39T are formed.

The magnet 40 is a magnet extending in the axial direction, and for example, a sintered magnet such as a ferrite magnet or a neodymium magnet can be used. The length of the magnet 40 in the axial direction is substantially the same as the length of the yoke 30 in the axial direction, for example. In this case, as shown in FIG. 2, the magnet 40 is arranged such that the axial end surface of the magnet 40 and the axial end surface of the yoke 30 are substantially flush with each other.

As shown in FIGS. 2 to 4, the first magnets 41 are arranged in the holes 38 surrounded by the frames 39, and the second magnets 42 are arranged in the gaps 35 sandwiched between the frames 39 adjacent in the circumferential direction. be. FIG. 3 is an enlarged top view showing an example of the motor in the embodiment. FIG. 4 is an enlarged top view showing an example of a yoke in the embodiment; FIG. 3 is an enlarged view of the portion indicated by frame F2 in FIG. FIG. 4 shows the yoke 30 before the first magnet 41 and the second magnet 42 shown in FIG. 3 are arranged.

As shown in FIG. 4 , the frame 39 is formed from an outer peripheral portion 31 , a pair of side portions 32 and 33 and an inner peripheral portion 34 . For example, the frame 39A is formed from an outer peripheral portion 31A, a pair of side portions 32A and 33A, and an inner peripheral portion . In embodiments, inner perimeter 34 is formed by the outer perimeter of annular portion 36 . In this case, the hole 38 is radially surrounded by the outer peripheral portion 31 and the annular portion 36, and circumferentially surrounded by the pair of side portions 32 and 33, respectively.

As shown in FIG. 4, the gap 35 is sandwiched between two frames 39 adjacent in the circumferential direction. More specifically, the gap 35 is formed by the side portion 32 of the frame 39 and the side portion 33 of the other frame 39 in the circumferential direction. For example, the gap 35A in FIG. 4 is sandwiched between the side portion 32A of the frame 39A and the side portion 33T of the frame 39T. The yoke 30 in the embodiment has the same number of gaps 35A-35T as the frame 39. FIG.

Sides 32 and 33 extend radially outwardly from annular portion 36 . In the embodiment, the sides 32 and 33 are formed slanted with respect to the radial direction, as indicated by arrows a1 and a2 in FIG. More specifically, sides 32 and 33 are angled outwardly with respect to hole 38 and angled inwardly with respect to gap 35 . For example, side 32A is angled outward (to the left in the drawing) with respect to hole 38A.

In this case, the width of the gap 35 in the circumferential direction differs between the inner side and the outer side in the radial direction. Specifically, the radially outer circumferential width Dc of the gap 35 is larger than the radially inner circumferential width Dd of the gap 35 . In the embodiment, the width of the gap 35 in the circumferential direction varies linearly with respect to the radial direction such that it is smallest on the radially outer side and largest on the radially inner side.

In the embodiment, the sides 32 and 33 are formed to have a constant size (width) in the circumferential direction. In this case, the size (width) in the circumferential direction of the hole 38 sandwiched between the side portions 32 and 33 also differs between the inner side and the outer side in the radial direction. Specifically, the radially outer circumferential width Da of the hole 38 is larger than the radially inner circumferential width Db of the hole 38 .

The first magnet 41 is inserted, for example, axially into the hole 38 surrounded by the frame 39 . The second magnet 42 is axially inserted into the gap 35 . In this case, the radial size (height) H2 of the second magnet 42 is greater than the radial size (height) H1 of the first magnet 41 . 3, the outer peripheral surface 45 of the second magnet 42 is formed so as to be substantially flush with the outer peripheral portion 31 of the frame 39, for example. In other words, in the radial direction, the distance from the center of the rotor 20 to the outer peripheral surface 45 of the second magnet 42 and the distance from the center of the rotor 20 to the outer peripheral portion 31 of the frame 39 are formed to be the same.

In the embodiment, the outer peripheral surface 45 of the second magnet 42 directly faces the stator 10 in the radial direction. On the other hand, the first magnet 41 faces the stator 10 via the outer peripheral portion 31 of the frame 39 in the radial direction. In this case, the radial distance D2 between the outer peripheral surface 45 of the second magnet 42 and the stator 10 is smaller than the radial distance D1 between the first magnet 41 and the stator 10 .

The size (width) Wp of the maximum portion of the second magnet 42 in the circumferential direction is larger than the size (width) Dc of the minimum portion of the gap 35 in the circumferential direction. In the embodiment, the circumferential width of the second magnet 42 is maximized near the inner peripheral surface 46, for example. This prevents the second magnet 42 from protruding radially outward from the gap 35 .

As described above, the motor 1 in the embodiment includes the rotor 20 having the yoke 30, the plurality of first magnets 41, and the second magnets . Yoke 30 includes a plurality of frames 39 having an outer periphery 31 . The plurality of first magnets 41 are arranged within the plurality of frames 39, respectively. The second magnet 42 is located in the gap 35 between two adjacent frames 39 among the plurality of frames 39 in the circumferential direction. The second magnet 42 has a portion 46 that is larger than the width Dc at the outer periphery of the two frames 39 in the circumferential direction. According to such a configuration, the magnetic flux flowing from the magnet 40 to the stator 10 is increased, so that the output torque can be improved.

[Modification]
Although the configuration in the embodiment has been described above, the embodiment is not limited to this. For example, the number of frames 39 provided in the yoke 30 and the number of gaps 35 formed in the yoke 30 are not limited to those shown in the embodiment. In addition, the portions of the frame 39 of the yoke 30 that protrude in the circumferential direction are not limited to the side portions 32 and 33 that are inclined with respect to the radial direction. The portion that protrudes in the circumferential direction may be, for example, a portion that is integrally formed with the annular portion 36 as in the configuration in the embodiment, or another member is separately formed as an engaging portion to extend radially of the annular portion 36. May be placed outside. The side portions 32 and 33 are engaging portions that engage with the first magnet 41 and the second magnet 42 . Furthermore, the material of the yoke is not limited to iron, and may be another magnetic material.

Also, the magnet 40 should not protrude further than the yoke 30 in the axial direction. In this case, the length in the axial direction of the magnet 40 may be smaller than the length in the axial direction of the yoke 30, for example. Further, although the motor 1 in the embodiment is an inner rotor type flat motor, it is not limited to this, and may be an outer rotor type motor, for example, in which the length of the motor in the axial direction is greater than the length in the radial direction. may

Also, the magnet 40 is not limited to a molded magnet such as a sintered magnet. For example, using a bond magnet or the like, the gap 35 and the hole 38 may be molded into any shape by an injection molding machine or the like. That is, the magnet 40 may be directly molded in the gap 35 and the hole 38 instead of mounting the molded magnet 40 in the hole 38 and the gap 35 of the yoke 30 from the axial direction.

In addition, the portion of the gap having the smallest width in the circumferential direction (hereinafter sometimes referred to as the minimum portion of the gap) is formed at a portion other than the portion facing the outer peripheral portion 31 of the frame 39, as shown in FIG. may have been Furthermore, the portion of the second magnet having the largest width in the circumferential direction (hereinafter sometimes referred to as the largest portion of the second magnet) is also formed in a portion other than the radially inner side as shown in FIG. good too. Furthermore, the circumferential size of the gap may vary non-linearly. FIG. 5 is an enlarged top view showing an example of the rotor in the first modified example. FIG. 6 is an enlarged top view showing an example of the rotor in the second modified example. In addition, in each of the following modified examples, the same parts as those shown in the previously described drawings are given the same reference numerals, and overlapping explanations are omitted. Further, the rotor 21 in the first modified example has the second magnets 42 , while the rotor 22 in the second modified example has the second magnets 72 formed in a shape substantially similar to the gap 65 . The first magnet 49 in the first modified example and the first magnet 71 in the second modified example have shapes substantially similar to the holes 58 and 68, respectively.

The yoke 50 in the first variant comprises an outer peripheral portion 51 and side portions 52 and 53 surrounding a hole 58 and an annular portion 36 . The side portions 52 and 53 of the yoke 50 are bent at intermediate portions between the inner side and the outer side in the radial direction, as shown in FIG.

In this case, as shown in FIG. 5, the minimum gap is formed near the middle between the outer peripheral surface 45 and the inner peripheral surface 46 of the second magnet 42 rather than the position facing the outer peripheral surface 45 of the second magnet 42 . Moreover, the width De in the circumferential direction of the portion of the gap 55 facing the outer peripheral surface 45 is larger than the maximum width Wp of the second magnet. Even in this case, since the size Dy of the minimum gap is smaller than the size Wp in the circumferential direction near the inner peripheral surface 46 of the second magnet 42, the second magnet 42 is prevented from protruding radially outward. be done.

Also, the yoke 60 in the second modification includes an outer peripheral portion 61 surrounding a hole 69, side portions 62 and 63, and an annular portion . As shown in FIG. 6, side portions 62 and 63 of the yoke 60 are bent in the direction opposite to the side portions 52 and 53 shown in FIG. 5 at intermediate portions between the inner side and the outer side in the radial direction.

In this case, as shown in FIG. 6, the largest portion of the second magnet is formed not near the inner peripheral surface 76 of the second magnet 72 but near the middle between the outer peripheral surface 75 and the inner peripheral surface 76. . In addition, the circumferential dimension Df of the gap 65 on the radially outer side is smaller than the circumferential dimension Wr near the inner peripheral surface 76 of the second magnet 72 . In this case as well, the size Wq of the largest portion of the second magnet is larger than the smallest portion Df of the gap 65 in the circumferential direction, so that the second magnet 72 is prevented from protruding radially outward.

As shown in each of the modifications described above, in the second magnet, a portion wider than the minimum gap portion may be formed radially inward of the minimum gap portion, or the gap may A portion narrower than the maximum portion of the second magnet may be formed radially outward of the maximum portion of the second magnet. However, in order to prevent the second magnet from protruding radially outward and coming into contact with the stator 10, the minimum gap and a portion of the second magnet wider than the minimum gap, or the second magnet in the gap It is desirable that the distance between the portion narrower than the largest portion of the second magnet and the largest portion of the second magnet be sufficiently small. Specifically, the distance in the radial direction between the minimum part of the gap and the part of the second magnet wider than the minimum part of the gap, or the distance between the part of the gap narrower than the maximum part of the second magnet and the second magnet It is preferable that the distance from the largest part of the magnet is smaller than the distance D2 between the second magnet and the stator 10 shown in FIG. Moreover, as shown in FIG. 5, it is desirable that the width of the side portion in the circumferential direction is constant even when it is bent. You can change the size.

Moreover, the structure which further has the 3rd magnet with which direction of magnetic flux differs from a 1st magnet and a 2nd magnet may be sufficient. FIG. 7 is an enlarged top view showing an example of the rotor in the third modified example. As shown in FIG. 7 , the rotor 23 in the third modification includes a second magnet 82 and a third magnet 83 instead of the second magnet 42 .

In the third modification, the second magnet 82 and the third magnet 83 have substantially the same shape, but have different magnetic flux directions. The second magnet 82 and the third magnet 83 are arranged in contact with each other in the circumferential direction so as to be bilaterally symmetrical.

Also in the third modification, as shown in FIG. 7, the width Ws of the second magnet 82 in the radial direction inside the gap 35 and the width Dc of the third magnet 83 in the circumferential direction The sum with the width Wt is larger. This prevents the second magnet 82 and the third magnet 83 from protruding radially outward.

Furthermore, in the embodiment, the configuration in which the shape of the second magnet 42 is substantially the same as the shape of the gap 35 has been described, but the embodiment is not limited to this. FIG. 8 is an enlarged top view showing an example of a rotor in the fourth modified example. As shown in FIG. 8 , the rotor 24 in the fourth modification includes a first magnet 91 different in shape from the first magnet 41 and a second magnet 92 different in shape from the second magnet 42 .

The second magnet 92 is formed such that a portion 96 facing the annular portion 36 of the yoke 30 in the radial direction has a curved shape. In the second magnet 92 , the inclination a3 of the portion facing the side portion 32 is different from the inclination a1 of the side portion 32 , and the inclination a4 of the portion facing the side portion 33 is different from the inclination of the side portion 33 .

As described above, the second magnet 92 may have a curved top surface shape, and may not be formed substantially parallel to the side portions. The same applies to the first magnet 91 as shown in FIG. Also, the side portions of the first magnet and the second magnet may have a curved top surface shape, and may not be formed substantially parallel to the annular portion of the yoke. Also in such a configuration, the circumferential width Wu near the radially inner side of the second magnet 92 is larger than the circumferential width Dc of the gap 35 at the radially outer side, so radially outward projection is suppressed.

The rotor or stator described in the embodiments and modifications of the present invention may be mounted on an actuator, an electronic device, or the like. Specifically, the rotor or stator according to the embodiments and modifications of the present invention is accommodated in a frame, housing, body, or the like of an actuator or an electronic device, and used as a drive element for the actuator or electronic device. may

As described above, the present invention has been described based on the embodiment and each modified example, but the present invention is not limited to the embodiment and each modified example, and various modifications can be made without departing from the gist of the present invention. It goes without saying that there is. Various modifications without departing from the gist of the invention are also included in the technical scope of the present invention, which will be apparent to those skilled in the art from the description of the claims.

Reference Signs List 1 motor 10 stator 11 stator core 12 insulator 13 coil 20,21,22,23,24 rotor 30,50,60 yoke 31,51,61 outer peripheral portion 32,33,52,53,62 , 63 side portion, 34 inner peripheral portion, 35 gap, 36 annular portion, 38 hole, 39 frame, 41, 49, 71, 91 first magnet, 42, 72, 82, 92 second magnet, 83 third magnet

Claims (7)

a rotor having a yoke, a plurality of first magnets, and a second magnet;
the yoke comprises a plurality of frames having an outer periphery,
The plurality of first magnets are arranged within the plurality of frames,
the second magnet is located between two adjacent frames among the plurality of frames in the circumferential direction;
The second magnet has a portion larger than the width between the outer peripheral portions of the two frames in the circumferential direction,
motor. with a stator,
In the radial direction, the outer peripheral portion of the second magnet faces the stator,
An outer peripheral portion of the first magnet faces the stator through the frame,
A motor according to claim 1. 3. The motor according to claim 1, wherein said frame has a portion radially inward of said outer peripheral portion in the circumferential direction, the portion being wider than the outer peripheral portion of said frame. The frame includes an outer peripheral portion, an inner peripheral portion, and a side portion connecting the outer peripheral portion and the inner peripheral portion,
4. A motor according to any one of claims 1 to 3, wherein the sides of the frame are inclined with respect to the radial direction. the yoke further comprises an annular portion forming inner peripheral portions of the plurality of frames;
the sides of the frame extend radially from the annular portion;
A motor according to any one of claims 1 to 4. 6. The motor according to any one of claims 1 to 5, wherein the second magnet includes an outer peripheral portion and a portion whose size in the circumferential direction is larger than the width of the outer peripheral portion in the circumferential direction. a rotor having a yoke, a plurality of first magnets, a second magnet, and a third magnet;
the yoke comprises a plurality of frames having an outer periphery,
The plurality of first magnets are arranged within the plurality of frames,
the second magnet and the third magnet are arranged adjacent to each other between two adjacent frames among the plurality of frames in the circumferential direction;
At any position inside the outer peripheral portion in the radial direction, the sum of the length in the circumferential direction of the second magnet and the length in the peripheral direction of the third magnet is equal to the length of the two adjacent parts in the outer peripheral portion greater than the spacing in the circumferential direction of the frame,
motor.

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