KR102517118B1 - Motor - Google Patents

Abstract

The embodiment includes a stator including a through hole, a cylindrical rotor disposed in the through hole, a rotor central axis formed in a central region of the rotor to which a rotation axis is coupled, and a first magnet and a second magnet disposed between the stator and the rotor. 2 magnets; The rotor includes an outer portion and a pattern portion formed between the outer portion and a central axis of the rotor, the pattern portion includes a plurality of unit patterns and a hollow portion formed in the unit pattern, and the outer portion includes the An outer circumferential surface on which the first and second magnets are disposed and an inner circumferential surface in contact with the plurality of unit patterns, and the inner circumferential surface of the outer portion further includes a first protrusion protruding in a first direction toward the central axis of the rotor. and, in the first direction, the maximum length of the first protrusion is greater than the maximum length of each unit pattern.

Description

motor {MOTOR}

The present invention relates to a motor.

In general, the motor rotates the rotor by electromagnetic interaction between the rotor and the stator. At this time, the rotational shaft inserted into the rotor also rotates to generate rotational driving force.

In addition, motors are recently used in automobiles, home appliances, robots, etc., and demand is rapidly increasing. However, the rotor may have a form in which metal plates are simply stacked in an axial direction in which a rotating shaft rotates. Accordingly, the rotor is formed of a metal plate even in a portion that is not affected by the electromagnetic force, so there is a problem in that the weight increases or decreases.

In addition, the motor has a limit in that power density is lowered due to the weight of the rotor.

Japanese Unexamined Patent Publication No. 2010-220388

An embodiment of the present invention is to provide a lightweight motor.

Further, an embodiment of the present invention is to provide a motor with improved power density.

Further, an embodiment of the present invention is to provide a motor that prevents torque reduction.

In addition, an embodiment of the present invention is to provide a motor with improved durability according to securing structural rigidity on the outside of the rotor.

The problem to be solved in the embodiment is not limited thereto, and it will be said that the solution to the problem described below or the purpose or effect that can be grasped from the embodiment is also included.

A motor according to an embodiment of the present invention includes a stator including a through hole, a cylindrical rotor disposed in the through hole, a rotor central axis formed in a central region of the rotor to which a rotation axis is coupled, and between the stator and the rotor. a first magnet and a second magnet disposed thereon; The rotor includes an outer portion and a pattern portion formed between the outer portion and a central axis of the rotor, the pattern portion includes a plurality of unit patterns and a hollow portion formed in the unit pattern, and the outer portion includes the An outer circumferential surface on which the first and second magnets are disposed and an inner circumferential surface in contact with the plurality of unit patterns, and the inner circumferential surface of the outer portion further includes a first protrusion protruding in a first direction toward the central axis of the rotor. and, in the first direction, a maximum length of the first protrusion is greater than a maximum length of each unit pattern.

The outer circumferential surface of the outer portion may further include a first spacer formed to form a space between the first magnet and the second magnet.

The first protrusion may be disposed in an imaginary straight line connecting the central axis and the center of the first spacer.

A plurality of unit patterns of the pattern part may be arranged in an imaginary straight line connecting the central axis and the center of the first spacer part.

An inner circumferential surface of the outer portion may further include a second protrusion spaced apart from the first protrusion and protruding in the first direction.

It may further include a third magnet disposed between the stator and the rotor, and the third magnet may be adjacent to the second magnet.

The second spacer may further include a second spacer formed in a space between the second magnet and the third magnet, and the second protrusion may be disposed in an imaginary straight line connecting the central axis and the center of the second spacer.

A plurality of unit patterns of the pattern part may be arranged in an imaginary straight line connecting the central axis and the center of the second spacer part.

A size of a cross section of any one of the first protrusion and the second protrusion may be 110% to 350% of a size of a cross section of any one of the first and second spacers.

A width of any one of the first protrusion and the second protrusion in a second direction perpendicular to the first direction may be smaller as it is closer to the central axis.

The outer portion may have a first thickness in the first direction, and either one of the first protrusion and the second protrusion may have a second thickness in the first direction, and the first thickness may be smaller than the second thickness. .

The first thickness may be 80% to 110% of the second thickness.

The pattern part may be exposed to the outside of the rotor.

On the other hand, a motor according to another embodiment of the present invention includes a stator including a through hole, a cylindrical rotor disposed in the through hole, a rotor central axis formed in a central region of the rotor and coupled to a rotation axis, and the stator and the rotor. A first magnet, a second magnet, and a third magnet are disposed therebetween, and the rotor includes an outer portion and a pattern portion formed between the outer portion and the central axis of the rotor, and the pattern portion includes a plurality of unit patterns. and a hollow formed within the unit pattern, wherein the outer portion includes an outer circumferential surface on which the first magnet, the second magnet, and the third magnet are disposed and an inner circumferential surface contacting the plurality of unit patterns, and an inner circumferential surface of the outer portion. further comprises a first protrusion protruding in a first direction toward the rotor central axis and a second protrusion disposed adjacent to the first protrusion and protruding in the first direction; A plurality of unit patterns of the pattern unit may be disposed between the protrusions.

It may further include a first spacer formed in a space between the first magnet and the second magnet, and the first protrusion may be disposed in an imaginary straight line connecting the central axis and the center of the first spacer.

A plurality of unit patterns of the pattern part may be arranged in an imaginary straight line connecting the central axis and the center of the first spacer part.

The second spacer may further include a second spacer formed in a space between the second magnet and the third magnet, and the second protrusion may be disposed in an imaginary straight line connecting the central axis and the center of the second spacer.

A plurality of unit patterns of the pattern part may be arranged in an imaginary straight line connecting the central axis and the center of the second spacer part.

A width of any one of the first protrusion and the second protrusion in a second direction perpendicular to the first direction may be smaller as it is closer to the central axis.

The pattern part may be exposed to the outside of the rotor.

According to an embodiment of the present invention, a motor with improved power density may be implemented.

In addition, according to an embodiment of the present invention, it is possible to implement a motor that prevents torque reduction.

In addition, according to an embodiment of the present invention, it is to provide a motor with improved durability according to securing structural rigidity on the outside of the rotor.

Various advantageous advantages and effects of the present invention are not limited to the above description, and will be more easily understood in the process of describing specific embodiments of the present invention.

1 is a side cross-sectional view of a general motor,
2 is a side cross-sectional view of a general motor for weight reduction,
3 is a cross-sectional view from A to A' of the motor of FIG. 2;
4 is an image showing the distribution of magnetic field analysis in 4 regions of FIG. 3;
5 is a side cross-sectional view of a motor according to an embodiment of the present invention;
6 is a cross-sectional view from B to B' of the motor of FIG. 5;
FIG. 7 is an enlarged view of area 7 of FIG. 6 .
8 is an enlarged view of region 8 of FIG. 7;
9 is a side cross-sectional view of a motor according to another embodiment of the present invention.

Since the present invention can make various changes and have various embodiments, specific embodiments are illustrated and described in the drawings. However, this is not intended to limit the present invention to specific embodiments, and should be understood to include all modifications, equivalents, and substitutes included in the spirit and scope of the present invention.

Terms including ordinal numbers such as second, first, etc. may be used to describe various components, but the components are not limited by the terms. These terms are only used for the purpose of distinguishing one component from another. For example, a second element may be termed a first element, and similarly, a first element may be termed a second element, without departing from the scope of the present invention. The terms and/or include any combination of a plurality of related recited items or any of a plurality of related recited items.

It is understood that when an element is referred to as being "connected" or "connected" to another element, it may be directly connected or connected to the other element, but other elements may exist in the middle. It should be. On the other hand, when an element is referred to as “directly connected” or “directly connected” to another element, it should be understood that no other element exists in the middle.

Terms used in this application are only used to describe specific embodiments, and are not intended to limit the present invention. Singular expressions include plural expressions unless the context clearly dictates otherwise. In this application, the terms "include" or "have" are intended to designate that there is a feature, number, step, operation, component, part, or combination thereof described in the specification, but one or more other features It should be understood that the presence or addition of numbers, steps, operations, components, parts, or combinations thereof is not precluded.

Unless defined otherwise, all terms used herein, including technical or scientific terms, have the same meaning as commonly understood by one of ordinary skill in the art to which the present invention belongs. Terms such as those defined in commonly used dictionaries should be interpreted as having a meaning consistent with the meaning in the context of the related art, and unless explicitly defined in the present application, they should not be interpreted in an ideal or excessively formal meaning. don't

Hereinafter, the embodiments will be described in detail with reference to the accompanying drawings, but the same or corresponding components regardless of reference numerals will be assigned the same reference numerals, and overlapping descriptions thereof will be omitted.

First, a general motor 10 will be described with reference to FIG. 1 .

1 is a side cross-sectional view of a general motor.

A typical motor 10 may include a rotating shaft 100, a rotor 200, and a stator 400.

The rotating shaft 100 may be coupled to the rotor 200 . When an electromagnetic interaction occurs between the rotor 200 and the stator 400 through the supply of current, the rotor 200 rotates and the rotating shaft 100 may rotate in conjunction therewith. The rotating shaft 100 may transmit power to an external device.

The rotor 200 rotates through electrical interaction with the stator 400.

On the other hand, the rotor 200 may be implemented in a shape in which a plurality of plates having a circular thin steel plate shape are stacked or in a single cylindrical shape. A hole for coupling the rotating shaft 100 may be disposed at the center of the rotor 200 .

A magnet (not shown) may be disposed on an outer circumferential surface or an inner side of the rotor 200 . In the case of a surface permanent magnet (SPM) type in which magnets are attached to the outer circumferential surface of the rotor 200, a plurality of magnets may be disposed along the outer circumferential surface of the rotor 200 at regular intervals. Alternatively, in the case of an interior surface magnet (IPM) type in which magnets are embedded inside the rotor 200, a plurality of magnets may be embedded inside the rotor 200 at regular intervals. Also, the rotor 200 may include a can member (not shown). A can member (not shown) surrounds the magnet to fix the magnet so that it is not separated from the rotor and prevents the magnet from being exposed.

A coil may be wound around the stator 400 to induce electrical interaction with the rotor 200 . The specific configuration of the stator 400 for winding the coil is as follows. The stator 400 may include a stator core including a plurality of teeth. The stator core may be provided with an annular yoke portion, and provided with teeth on which a coil is wound in a central direction from the yoke. Teeth may be provided at regular intervals along the outer circumferential surface of the yoke portion. Meanwhile, the stator core may be formed by mutually stacking a plurality of plates in the form of thin steel plates. In addition, the stator core may be formed by coupling or connecting a plurality of split cores to each other.

The motor 10 may include a bus bar 450 . The bus bar 450 may be disposed above the stator 400 . The bus bar 450 may include a terminal inside the annular mold member.

The housing 900 of the motor may accommodate the rotor 200 and the stator 400 therein. The housing 900 may include a body and a bracket. The body has a cylindrical shape. The body may be made of a metal material such as aluminum. And, the upper part of the body is open. A bracket covers the open top of the body. The stator 400 is located inside the body, and the rotor 200 may be disposed inside the stator 400. A bearing may be disposed at the center of the bracket. The bearing may be double-injected and integral with the bracket.

The sensing magnet 600 is a device for detecting the position of the rotor 200 by being coupled to the rotating shaft 100 so as to interlock with the rotor 200 .

A sensor for sensing the magnetic force of the sensing magnet 600 may be disposed on the printed circuit board 700 . In this case, the sensor may be a Hall IC. The sensor detects a change in N pole and S pole of the sensing magnet 600 to generate a sensing signal.

Next, with reference to FIGS. 2 to 4, a general motor 20 for weight reduction will be additionally described. Here, the same reference numerals will be used for the same and overlapping configurations as those of the motor 10 of FIG. 1 .

2 is a side cross-sectional view of a motor for light weight, FIG. 3 is a top cross-sectional view of the motor of FIG. 2, and FIG. 4 is an image showing the magnetic field analysis distribution of four regions of FIG.

The motor 20 for weight reduction includes a rotating shaft 100, a rotor 200, a magnet 300, and a stator 400.

The rotor 200 and the stator 400 may electrically interact with each other. When an electrical interaction is induced, the rotor 200 may rotate. The rotating shaft 100 may also rotate in conjunction with the rotation of the rotor 200 . The rotating shaft 100 may be connected to power bodies of various devices to transmit power to the power bodies. The rotating shaft 100 may be surrounded by a rotor 200 , a magnet 300 and a stator 400 . The rotor 200, the magnet 300, and the stator 400 may have a long distance from the central axis C in the order of the rotor 200, the magnet 300, and the stator 400. Also, the rotating shaft 100 may pass through the rotor 200 , the magnet 300 and the stator 400 .

The rotor 200 may be disposed so as to come into contact with the rotational shaft 100 and surround the rotational shaft 100 . The rotor 200 may include a hole through which the rotating shaft 100 passes. And the rotation shaft 100 may be inserted into the hole.

Alternatively, the rotor 200 may be integrally formed with the rotation shaft 100.

The rotor 200 may include a pattern portion 210 and a rotor core 220 .

First, the rotor core 220 may include a groove. Grooves may be formed on the inner surface of the rotor 200 . That is, the groove may be disposed inside the rotor core 220.

The pattern unit 210 may have a hole into which the rotation shaft 100 is inserted or may be integrally formed with the rotation shaft 100 . That is, the pattern unit 210 may be disposed adjacent to the rotation shaft 100 . The pattern unit 210 may be disposed in contact with the rotating shaft 100 . Accordingly, the pattern unit 210 may contact the rotating shaft 100 .

Also, the pattern unit 210 may include a plurality of openings. The pattern unit 210 may form a lattice structure by a plurality of openings. Accordingly, in the rotor 200, a lattice structure may be formed adjacent to the through hole. With this configuration, in the motor 20 according to the embodiment, the pattern portion including the opening is located inside the rotor 200 so that electrical interaction between the stator 400 and the rotor 200 occurs outside the rotor 200. may not be hindered. Also, since the pattern portion 210 includes the opening, the manufacturing cost of the motor 20 according to the embodiment is reduced, and the weight of the motor is reduced, thereby providing an effect of improving power density of the motor. Here, the power density means the size of the motor compared to the output of the motor, and the improvement of the power density means that the size (size) of the motor is reduced under the same output (torque).

The magnet 300 may be disposed on the rotor core 220 . The rotor core 220 may be disposed outside the rotor 200 . Also, as a modified example, the groove of the rotor core 220 may be hollow. For example, the rotor core 220 may be arranged to include the pattern portion 210 therein. In this case, the inner surface of the rotor core 220 may come into contact with the rotating shaft 100 . Accordingly, the pattern unit 210 does not come into contact with the rotating shaft 100, and the inner surface of the rotor core 220 comes into contact with the rotating shaft 100, so that the coupling force between the rotating shaft 100 and the rotor 200 can be improved.

The magnet 300 may be magnetized with a plurality of poles. The magnet 300 may be arranged so that its center is the same as the central axis (C). Thus, the magnet 300 may have the same central axis C as the rotor 200 . These magnets 300 can generate a signal for detecting the rotational position of the rotor core 220 . Also, the magnet 300 may be implemented in a ring shape. The magnet 300 may include a hole through which the rotation shaft 100 penetrates at its center.

The stator 400 may include a through hole into which the rotating shaft 100, the rotor 200, and the magnet 300 are inserted. The stator 400 may have the largest diameter relative to the rotation shaft 100, the rotor 200, and the magnet 300 based on the central axis C.

However, referring to FIG. 4 , the thickness of the rotor core 220 is reduced according to the formation of the pattern portion 210 for weight reduction, and as a result, in the spaced area A between the magnets 300 and the magnets 300 There is a problem in that the magnetic resistance increases due to the magnetic saturation phenomenon, and thus the output density of the motor decreases and the torque decreases.

In addition, as the thickness of the rotor core 220 decreases as a whole according to weight reduction and the volume ratio of the pattern part 210 increases, it is difficult to trust the structural rigidity of the motor 20 .

Hereinafter, a motor according to an embodiment of the present invention will be described with reference to FIGS. 5 to 8 . However, the motor 20 according to an embodiment of the present invention is the same as the motor 20 shown in FIGS. 2 and 3, and the same reference numerals are used to describe overlapping components.

5 is a side cross-sectional view of a motor according to an embodiment of the present invention, FIG. 6 is a cross-sectional view from B to B′ of the motor of FIG. 5, FIG. 7 is an enlarged view of area 7 of FIG. 6, FIG. 8 is an enlarged view of region 8 of FIG. 7 .

5 to 8 , a motor 20 according to an embodiment of the present invention includes a rotating shaft 100, a rotor 500, a magnet 300, and a stator 400.

The rotor 500 and the stator 400 may electrically interact with each other. When an electrical interaction is induced, the rotor 500 may rotate. The rotating shaft 100 may also rotate in association with the rotation of the rotor 500 . The rotating shaft 100 may be connected to power bodies of various devices to transmit power to the power bodies.

The rotating shaft 100 may be surrounded by a rotor 500 , a magnet 300 and a stator 400 . The rotor 500, the magnet 300, and the stator 400 may have a long distance from the central axis C in the order of the rotor 500, the magnet 300, and the stator 400. Also, the rotating shaft 100 may pass through the rotor 500 , the magnet 300 and the stator 400 .

The rotor 500 may be disposed so as to come into contact with the rotational shaft 100 and surround the rotational shaft 100 . The rotor 500 may be integrally formed with the rotating shaft 100 or may include a first through hole through which the rotating shaft 100 passes. Also, the rotation shaft 100 may be inserted into the first through hole.

The rotor 500 may include a pattern portion 510 and an outer portion 520 . Such a rotor 500 is preferably implemented in a PBF (Power Bed Fusion) method among metal 3D printing technologies.

The pattern unit 510 includes a plurality of unit patterns 511, and each of the plurality of unit patterns 511 may be formed in a prismatic or circular pattern having a hollow part 511a. That is, the pattern unit 510 may form a lattice structure or a honeycomb structure.

The pattern unit 510 may be exposed to the outside.

Meanwhile, the pattern unit 510 may be formed only inside the rotor 500 without being exposed to the outside.

With this configuration, in the motor 20 according to the embodiment, the pattern portion 510 including a plurality of hollow portions 511a is located inside the rotor 500 so that the rotor is positioned between the stator 400 and the rotor 500. (500) Electrical interactions occurring outside may not be inhibited. And since the pattern part 510 includes the hollow part 511a, the manufacturing cost of the motor 20 according to the embodiment is reduced, and the weight of the motor is reduced, thereby providing an effect of improving the power density of the motor. . Here, the power density means the size of the motor compared to the output of the motor, and the improvement of the power density means that the size (size) of the motor is reduced under the same output (torque).

In addition, a first through hole may be formed in the central axis of the pattern unit 510 .

That is, the pattern unit 510 may be disposed adjacent to the rotation shaft 100 , and the pattern unit 510 may be disposed in contact with the rotation shaft 100 .

In addition, as shown in FIG. 9 , a non-patterned rotor core portion 530 without a pattern may be disposed between the pattern portion 510 and the rotating shaft 100 .

Meanwhile, a jig hole (not shown) may be formed in the pattern unit 510 to mount a jig for assembly.

The outer part 520 forms the outermost part of the rotor 500 and includes an outer circumferential surface 521 and an inner circumferential surface 522 .

The outer circumferential surface 521 faces the stator 400, and the inner circumferential surface 522 faces the central axis C.

In addition, a plurality of magnets 300 are disposed on the outer circumferential surface 521 , and a plurality of protrusions 522a and 522b protrude toward the central axis C on the inner circumferential surface 522 .

Meanwhile, a guide protrusion (not shown) may be formed on the outer circumferential surface 521 to guide the arrangement of the plurality of magnets 300 .

Here, referring to FIG. 7 , the plurality of magnets 300 are adjacent to each other along the outer circumferential surface 521 of the outer portion 520 and the first magnet 310, the second magnet 320 and the third magnet arranged to be spaced apart. (330).

On the outer circumferential surface 521 of the outer portion 520, the first magnet 310 and the second magnet 320 may be spaced apart from each other to form a first spaced portion S1. In addition, on the outer circumferential surface 521 of the outer portion 520, the second magnet 320 and the third magnet 330 may be spaced apart from each other to form a second spaced portion S2.

Here, as shown in FIG. 7 , the first separation portion S1 may have a predetermined area through an imaginary straight line connecting upper portions of the first magnet 310 and the second magnet 320 in a cross-sectional view. In addition, the second spaced portion S2 may have a predetermined area through an imaginary straight line connecting upper portions of the second magnet 320 and the third magnet 330 .

On the other hand, it is preferable that the area of the first spacer (S1) and the second spacer (S2) are the same.

In addition, as shown in FIG. 7 , the plurality of protrusions 522a and 522b are adjacent to each other along the inner circumferential surface 522 of the outer portion 520 and the first protrusion 522a and the second protrusion 522b disposed to be spaced apart. can include

Each of the first protrusion 522a and the second protrusion 522b is formed to protrude in a first direction, which is a direction extending from the inner circumferential surface 522 of the outer portion 520 toward the central axis C of the rotor 500.

Here, it is preferable that the outer portion 520, the first protrusion 522a, and the second protrusion 522b are integrally formed.

That is, in the area where the first protrusion 522a and the second protrusion 522b are formed in the first direction, the thickness of the outer portion 520 is the area where the first protrusion 522a and the second protrusion 522b are not formed. formed larger than

Through this, structural rigidity of the outer portion 520 of the rotor 500 may be secured.

Here, the width of the first protrusion 522a or the second protrusion 522b in a second direction perpendicular to the first direction may gradually or gradually decrease as the width approaches the central axis C of the rotor 500. .

That is, the area ratio of the pattern portion 510 is increased as much as possible on the inside of the rotor 500 to reduce weight, and the area ratio of the outer portion 520 is increased on the outside of the rotor 500 to reduce structural rigidity and magnetic resistance. can make it big

On the other hand, the first protrusion 522a is disposed within an imaginary straight line L1 connecting the center of the first spacer S1 from the central axis C of the rotor 500, and the second protrusion 522b is the rotor ( 500) may be disposed within an imaginary straight line L2 connecting the center of the second spaced part S2 from the central axis C.

Meanwhile, in the same cross-section, the area of the first protrusion 522a may be 110% to 350% of the area of the first spacer S1. Also, the area of the second protrusion 522b may be 110% to 350% of the area of the second spacer S2 in the same cross section.

Here, when the area of the first protrusion 522a is set to 110% or less compared to the area of the first spacer S1, the rotor corresponds to the first spacer S1, which is an area where the magnet 300 is not disposed. (500) It is difficult to prevent the performance of the motor 20 from being reduced due to high magnetic resistance due to magnetic saturation in the outer portion 520.

In addition, when the area of the first protrusion 522a is set to be 350% or more of the area of the first spacer S1, the outer portion 520 in which the first protrusion 522a is formed has a thickness and an area larger than necessary. increase, there is a problem that the weight reduction of the motor 20 cannot be maintained.

Meanwhile, in the first direction, the outer portion 520 has a first thickness T1, the first protrusion 522a has a second thickness T2, and the first thickness T1 has a second thickness T2. It may be formed to 80% to 110% compared.

Here, when the first thickness T1 of the outer portion 520 is set to 80% or less of the second thickness T2 of the first protrusion 522a, the first spaced area, which is an area where the magnet 300 is not disposed, It is difficult to prevent the performance of the motor 20 from being reduced due to high magnetic resistance due to magnetic saturation in the outer portion 520 of the rotor 500 corresponding to the portion S1.

In addition, when the first thickness T1 of the outer portion 520 is set to 110% or more compared to the second thickness T2 of the first protruding portion 522a, the outer portion 520 having the first protruding portion 522a formed thereon The thickness and area are increased more than necessary, and there is a problem in that the weight reduction of the motor 20 cannot be maintained.

Meanwhile, as shown in FIGS. 7 and 8 , since the plurality of unit patterns 511 of the pattern unit 510 are formed very small compared to the sizes of the first protrusion 522a and the second protrusion 522b, A plurality of unit patterns 511 may be disposed between the first protrusion 522a and the second protrusion 522b.

In addition, a plurality of unit patterns 511 may be disposed between the central axis C of the rotor 500 and the first protrusion 522a on the imaginary first straight line L1.

In addition, a plurality of unit patterns 511 may be disposed between the central axis C of the rotor 500 and the second protrusion 522b on the imaginary second straight line L2.

As a result, the weight of the rotor 500 can be reduced. Here, the maximum length (W1) of the length (W) of each unit pattern 511 measured in various directions may be set to approximately 0.5 mm to 5 mm, and the maximum length (W1) of the unit pattern 511 is Among the lengths D of the first protrusion 522a or the second protrusion 522b measured in various directions, 5% to 50% of the maximum length D1 may be formed, and the first protrusion 522a and the second protrusion 522a Structural reliability of the rotor 500 may be secured through a honeycomb structure formed by a plurality of unit patterns 511 arranged to surround 522b.

The magnet 300 may be disposed on the outer circumferential surface 521 of the outer portion 520 of the rotor 500 .

The magnet 300 may be magnetized with a plurality of poles. Such a magnet 300 may generate a signal for detecting the rotational position of the rotor 500. Also, the magnet 300 may be implemented in a ring shape.

The stator 400 may include a second through hole into which the rotating shaft 100, the rotor 500, and the magnet 300 are inserted. The rotation shaft 100, the rotor 500, and the magnet 300 may be disposed in the second through hole of the stator 400.

The stator 400 may have the largest diameter relative to the rotation shaft 100, the rotor 500, and the magnet 300 based on the central axis C.

Although the above has been described with reference to the embodiments, this is only an example and does not limit the present invention, and those skilled in the art to which the present invention belongs will not deviate from the essential characteristics of the present embodiment. It will be appreciated that various variations and applications are possible. For example, each component specifically shown in the embodiment can be modified and implemented. And differences related to these modifications and applications should be construed as being included in the scope of the present invention as defined in the appended claims.

Claims (20)

A stator including a through hole;
a cylindrical rotor disposed within the through hole;
a rotor central axis formed in a central region of the rotor and to which a rotational axis is coupled; and
first and second magnets disposed between the stator and the rotor; including,
the rotor,
outer part;
a pattern portion formed between the outer portion and the central axis of the rotor; including,
The pattern part includes a plurality of unit patterns and a hollow part formed in the unit pattern,
The outer portion includes an outer circumferential surface on which the first magnet and the second magnet are disposed and an inner circumferential surface in contact with the plurality of unit patterns,
The inner circumferential surface of the outer portion further includes a first protrusion protruding in a first direction toward the rotor central axis and a second protrusion spaced apart from the first protrusion and protruding in the first direction,
In the first direction, the maximum length of the first protrusion is greater than the maximum length of each unit pattern,
In the first direction, the outer portion has a first thickness, and in the first direction, either one of the first protrusion and the second protrusion has a second thickness,
The first thickness is 80% to 110% of the second thickness motor.
According to claim 1,
A motor further comprising a first spacer formed on an outer circumferential surface of the outer portion to form a space between the first magnet and the second magnet.
According to claim 2,
The first protrusion is disposed in an imaginary straight line connecting the central axis and the center of the first spacer.
According to claim 3,
A motor in which a plurality of unit patterns of the pattern unit are arranged in an imaginary straight line connecting the central axis and the center of the first separation unit.
delete According to claim 4,
Further comprising a third magnet disposed between the stator and the rotor,
The third magnet is a motor adjacent to the second magnet.
According to claim 6,
Further comprising a second spacer formed in a space between the second magnet and the third magnet,
The second protrusion is disposed in an imaginary straight line connecting the central axis and the center of the second spacer.
According to claim 7,
A motor in which a plurality of unit patterns of the pattern unit are arranged in an imaginary straight line connecting the central axis and the center of the second spacer.
According to claim 7,
Any one of the first protrusion and the second protrusion has a cross-sectional size of 110% to 350% of the cross-sectional size of any one of the first spacer or the second spacer.
According to claim 7,
A width of any one of the first protrusion and the second protrusion in a second direction perpendicular to the first direction is smaller as it is closer to the central axis.
delete delete According to claim 1,
The pattern portion of the motor exposed to the outside of the rotor.
According to claim 1,
A motor in which a plurality of unit patterns of the pattern unit are disposed between the first protrusion and the second protrusion. delete delete delete delete delete delete

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