阅读说明：本技术 转子及具有该转子的电机 (Rotor and motor with same ) 是由 韩知勋 于 2019-07-03 设计创作，主要内容包括：本发明的一个实施例涉及一种转子及具有该转子的电机,该转子包括：转子芯；在转子芯的外周面上彼此间隔开地布置的多个磁体,其中,转子芯包括主体和从主体的内周面以规定角度向内倾斜地突出的突出部,其中在主体的内周面与每个突出部的端部之间形成规定的间隙(G1)。因此,转子和具有该转子的电机可以通过利用突起使转子芯的外周面的变化量最小化。因此,可以防止附接到转子芯的外周面上的磁体的分离。(One embodiment of the present invention relates to a rotor and a motor having the same, the rotor including: a rotor core; and a plurality of magnets arranged spaced apart from each other on an outer circumferential surface of the rotor core, wherein the rotor core includes a main body and protruding portions that protrude obliquely inward at a prescribed angle from an inner circumferential surface of the main body, wherein a prescribed gap (G1) is formed between the inner circumferential surface of the main body and an end of each protruding portion. Therefore, the rotor and the motor having the same can minimize the amount of change in the outer circumferential surface of the rotor core by using the protrusions. Therefore, separation of the magnets attached to the outer peripheral surface of the rotor core can be prevented.)

1. A rotor, comprising:

a rotor core; and

a plurality of magnets provided on an outer circumferential surface of the rotor core at intervals from each other,

wherein the rotor core includes a main body and a protrusion portion that protrudes obliquely inward at a prescribed angle from an inner circumferential surface of the main body, and

a predetermined gap (G1) is formed between the inner peripheral surface of the main body and an end of the protruding portion.

2. The rotor of claim 1,

the protrusion includes a first protrusion and a second protrusion which are obliquely protruded from the inner circumferential surface of the body at a predetermined angle, and

the first protrusion and the second protrusion are symmetrically disposed based on an imaginary line connecting a center of the rotor core and a center of the magnet.

3. The rotor of claim 1,

the protrusion includes a first protrusion and a second protrusion which are obliquely protruded from the inner circumferential surface of the body at a predetermined angle, and

an end of the first protrusion and an end of the second protrusion protrude in a direction spaced apart from each other in a circumferential direction.

4. The rotor of claim 3,

the end of the first protrusion and the end of the second protrusion form a first angle (θ 1) based on a center (C) of the rotor core,

one corner and the other corner of the magnet form a second angle (θ 2) based on the center (C) of the rotor core, and

the first angle (θ 1) is smaller than the second angle (θ 2).

5. The rotor of claim 4,

the center of the magnet and the center between the first protrusion and the second protrusion are disposed on the same radius line in the circumferential direction, and

the width of the magnet is greater than the width of the protrusion.

6. The rotor of claim 3, wherein the rotor core further comprises a bore formed in the body.

7. The rotor of claim 6, wherein the hole is disposed between the protrusion and the magnet in a radial direction.

8. The rotor of claim 7,

the end of the first protrusion and the end of the second protrusion form a first angle (θ 1) based on a center (C) of the rotor core,

one corner and the other corner of the hole form a third angle (θ 3) based on the center (C) of the rotor core, and

the first angle (θ 1) is greater than the third angle (θ 3).

9. The rotor of claim 8, wherein a center of the hole is disposed on an imaginary line (L) connecting a center of the magnet and a center of the rotor core.

10. The rotor of claim 8, wherein a width of the hole is the same as a width between one point and another point where the protrusion meets the inner circumferential surface of the main body in the circumferential direction.

11. The rotor of claim 1, wherein a height (H1) of the protrusion is less than a height (H2) of the main body based on a lower surface of the main body in an axial direction.

12. The rotor of claim 1, further comprising first and second cans covering upper and lower portions of the rotor core to which the magnets are attached, respectively,

wherein the second tank is disposed to overlap the protrusion in a radial direction.

13. The rotor of claim 1,

the rotor core further includes a groove formed concavely inward from an outer circumferential surface of the main body, and

the width of the groove is smaller than the width of the magnet.

14. The rotor of claim 13, wherein a prescribed gap (G2) is formed between an inner side surface of the magnet and an inner surface of the groove.

15. The rotor of claim 1,

the rotor core further includes a guide protruding outward from the outer circumferential surface of the rotor core, and

the magnet is disposed between the guides.

16. An electric machine comprising:

a shaft;

a rotor, the shaft being disposed in a central portion of the rotor; and

a stator disposed outside the rotor,

wherein the rotor includes a rotor core and a plurality of magnets disposed on an outer circumferential surface of the rotor core at intervals from each other,

the rotor core includes a main body and a protrusion portion protruding from an inner circumferential surface of the main body at a predetermined angle and inclined inward

A predetermined gap (G1) is formed between the inner peripheral surface of the main body and an end of the protruding portion.

17. The electric machine of claim 16,

the outer peripheral surface of the shaft is in contact with the protruding portion, and

the gap (G1) decreases when the shaft is inserted.

18. The electric machine according to claim 16, wherein a height (H1) of the protrusion is less than a height (H2) of the body based on a lower surface of the body in an axial direction.

19. The electric machine of claim 16,

the protrusion includes a first protrusion and a second protrusion which are obliquely protruded from the inner circumferential surface of the body at a predetermined angle, and

an end of the first protrusion and an end of the second protrusion protrude in a direction spaced apart from each other in a circumferential direction.

20. The electric machine of claim 19,

each of the end portion of the first protrusion and the end portion of the second protrusion is formed to have a curved surface; and is

The shaft is in line contact with the first protrusion and the second protrusion in an axial direction.

Technical Field

The present invention relates to a rotor and a motor including the same.

Background

The motor is a device configured to convert electric energy into mechanical energy to obtain rotational force, and is widely used for vehicles, household appliances, industrial machines, and the like.

The motor may include a housing, a shaft, a stator disposed in the housing, and a rotor mounted on an outer circumferential surface of the shaft. In this case, the stator of the motor electrically interacts with the rotor to cause rotation of the rotor. In addition, the shaft also rotates in accordance with the rotation of the rotor.

Specifically, the motor may be used for a device configured to ensure steering stability of the vehicle. For example, the motor may be used as a vehicle motor in an Electronic Power Steering (EPS) system or the like.

Additionally, the motor may be used in a clutch actuator.

A plurality of magnets are mounted on a rotor, which is classified into an Interior Permanent Magnet (IPM) type rotor in which magnets are inserted to be coupled to the interior of a rotor core or a Surface Permanent Magnet (SPM) type rotor in which magnets are attached to the surface of a rotor core according to a magnet mounting method.

In the case where the motor includes the SPM type rotor, since the magnet is coupled to the rotor core only by bonding, when the bonding force is reduced, a problem of the magnet being separated from the rotor core occurs.

Specifically, when the shaft is press-fitted into a hole formed in the rotor core, a press-fitting force is applied to the rotor core in the radial direction. Therefore, the outer peripheral surface of the rotor core, that is, the outer diameter of the rotor core changes due to the press-fitting force. In addition, due to variations in the outer diameter and press-fitting force, a problem occurs in that the magnet attached to the outer circumferential surface of the rotor core is separated from the rotor core.

Disclosure of Invention

Technical problem

The present invention is directed to provide a rotor in which separation of magnets attached to an outer circumferential surface of a rotor core is prevented by a protrusion configured to mitigate a variation in an outer diameter of the rotor core due to press-fitting of a shaft, and a motor including the rotor.

The object to be solved by the present invention is not limited to the above object, and other objects not described above will be clearly understood from the following description by those skilled in the art.

Technical scheme

One aspect of the present invention provides a rotor, comprising: a rotor core; and a plurality of magnets provided on an outer circumferential surface of the rotor core at intervals from each other, wherein the rotor core includes a main body and a protrusion portion protruding obliquely inward at a prescribed angle from an inner circumferential surface of the main body, and a prescribed gap (G1) is formed between the inner circumferential surface of the main body and an end of the protrusion portion.

The protrusion may include a first protrusion and a second protrusion that protrude obliquely at a prescribed angle from an inner circumferential surface of the main body, and the first protrusion and the second protrusion may be symmetrically disposed based on an imaginary line connecting a center of the rotor core and a center of the magnet.

Alternatively, the protrusion may include first and second protrusions obliquely protruding at a prescribed angle from an inner circumferential surface of the body, and an end of the first protrusion and an end of the second protrusion may protrude in a direction spaced apart from each other in a circumferential direction.

The end of the first protrusion and the end of the second protrusion may form a first angle (θ 1) based on the center (C) of the rotor core, one corner and the other corner of the magnet may form a second angle (θ 2) based on the center (C) of the rotor core, and the first angle (θ 1) may be smaller than the second angle (θ 2).

The center of the magnet and the center between the first protrusion and the second protrusion may be disposed on the same radius line in a circumferential direction, and the width of the magnet may be greater than the width of the protrusion.

The rotor core may further include a hole formed in the main body.

The hole may be disposed between the protrusion and the magnet in the radial direction.

The end of the first protrusion and the end of the second protrusion may form a first angle (θ 1) based on the center (C) of the rotor core, one corner and the other corner of the hole may form a third angle (θ 3) based on the center (C) of the rotor core, and the first angle (θ 1) may be greater than the third angle (θ 3).

The center of the hole may be disposed on an imaginary line (L) connecting the center of the magnet and the center of the rotor core.

Alternatively, the width of the hole may be the same as the width between one point and another point where the protrusion meets the inner circumferential surface of the main body in the circumferential direction.

In the axial direction, a height (H1) of the protrusion may be smaller than a height (H2) of the body based on a lower surface of the body.

The height (H2) of the body may be 1.9 to 2.0 times the height (H1) of the protrusion.

The rotor may further include first and second cans covering upper and lower portions of the rotor core to which the magnets are attached, respectively, wherein the second can may be disposed to overlap the protrusion in a radial direction.

The rotor core may further include a groove formed concavely inward from an outer circumferential surface of the main body, and a width of the groove may be smaller than a width of the magnet.

A prescribed gap (G2) may be formed between the inner side surface of the magnet and the inner surface of the groove.

The rotor core may further include guide members protruding outward from an outer circumferential surface of the rotor core, and the magnet may be disposed between the guide members.

Another aspect of the present invention provides a motor including: a shaft; a rotor having a shaft disposed in a central portion thereof; and a stator provided outside the rotor, wherein the rotor includes a rotor core and a plurality of magnets provided on an outer circumferential surface of the rotor core at intervals from each other, the rotor core includes a main body and a protrusion portion protruding obliquely inward at a prescribed angle from an inner circumferential surface of the main body, and a prescribed gap (G1) is formed between the inner circumferential surface of the main body and an end of the protrusion portion.

The outer peripheral surface of the shaft may contact the protrusion, and the gap (G1) may be reduced when the shaft is inserted.

In the axial direction, a height (H1) of the protrusion may be smaller than a height (H2) of the body based on a lower surface of the body.

The protrusion may include a first protrusion and a second protrusion that protrude obliquely at a prescribed angle from an inner circumferential surface of the body, and an end of the first protrusion and an end of the second protrusion may protrude in a direction spaced apart from each other in a circumferential direction.

Each of the end portion of the first protrusion and the end portion of the second protrusion may be formed to have a curved surface, and the shaft may be in line contact with the first protrusion and the second protrusion in an axial direction.

Advantageous effects

According to an embodiment of the present invention, in the rotor having the above-described configuration and the motor including the rotor, the amount of change in the outer peripheral surface of the rotor core can be minimized by the protrusions. Therefore, separation of the magnets attached to the outer peripheral surface of the rotor core can be prevented.

In addition, in the rotor core, by using the hole, it is possible to minimize the variation of the outer peripheral surface of the rotor core due to the press-fitting of the shaft.

In addition, in the rotor core, with the groove, it is possible to minimize variation in the outer peripheral surface of the rotor core due to press-fitting of the shaft.

In addition, since the shape of the first tank is implemented to be the same as that of the second tank, the production cost of the tank can be reduced. In addition, with the first tank and the second tank, separation of the magnets can be prevented.

Advantageous advantages and effects of the embodiments are not limited to the above, and will be more easily understood through the description of the specific embodiments.

Drawings

Fig. 1 is a view illustrating a motor according to an embodiment.

Fig. 2 is a perspective view illustrating a rotor of a motor according to an embodiment.

Fig. 3 is a side view illustrating a rotor of a motor according to an embodiment.

Fig. 4 is a perspective view illustrating a rotor core and a magnet of a rotor of a motor according to an embodiment.

Fig. 5 is a plan view illustrating a rotor core and a magnet of a rotor of a motor according to an embodiment.

Fig. 6 is an enlarged view illustrating a region a of fig. 5.

Fig. 7 is a perspective view illustrating a rotor core of a rotor provided in a motor according to an embodiment.

Fig. 8 is a plan view illustrating a rotor core of a rotor provided in a motor according to an embodiment.

Fig. 9 is a sectional view showing a rotor core of a rotor provided in a motor according to the embodiment.

Fig. 10 is an enlarged view illustrating a region B of fig. 9.

Fig. 11 is a view showing a rotor of a motor according to a comparative example.

Fig. 12 is a graph showing the amount of change in the outer diameter of the rotor core of the motor according to the comparative example and the amount of change in the outer diameter of the rotor core provided in the motor according to the embodiment.

Detailed Description

Hereinafter, exemplary embodiments of the present invention will be described in detail with reference to the accompanying drawings.

However, the technical idea of the present invention is not limited to some embodiments to be described, and may be implemented using various other embodiments, and at least one of the components of the embodiments may be selectively combined, substituted and used to implement the technical idea within the scope of the technical idea.

In addition, unless otherwise explicitly and specifically defined by the context, all terms (including technical and scientific terms) used herein may be interpreted in a meaning that is commonly understood by those skilled in the art, and the meaning of commonly used terms such as defined in commonly used dictionaries will be interpreted in view of the contextual meaning of the prior art.

In addition, the terms used in the embodiments of the present invention are considered to be descriptive meanings, and are not intended to limit the present invention.

In this specification, the singular form includes the plural form thereof, and in the case of the description of "at least one (or more than one) of A, B and C", it may include at least one combination of all possible combinations of A, B and C, unless the context clearly indicates otherwise.

In addition, in the description of the components of the present invention, terms such as "first", "second", "a", "B", "a", and "(B)" may be used.

These terms are only intended to distinguish one element from another element, and the nature, order, etc. of the elements are not limited by the terms.

It will be understood that when an element is referred to as being "connected" or "coupled" to another element, such description may include the case where the element is directly connected or coupled to the other element, and the case where the element is connected or coupled to the other element with another element interposed therebetween.

In addition, where any element is described as being formed or disposed "on or under" another element, such description includes instances where two elements are formed or disposed in direct contact with each other, and instances where one or more other elements are disposed between the two elements. In addition, when one element is described as being formed "on" or "under" another element, such description may include the case where one element is formed on the upper side or the lower side with respect to the other element.

Hereinafter, the embodiments will be described in detail with reference to the drawings, and the same or components corresponding to each other are denoted by the same reference numerals regardless of the figure numbers, and repeated descriptions thereof will be omitted.

Fig. 1 is a view illustrating a motor according to an embodiment. The x direction of fig. 1 represents the axial direction, and the y direction represents the radial direction. In this case, the axial direction is perpendicular to the radial direction. Here, the axial direction may be a longitudinal direction of the shaft 500.

Referring to fig. 1, a motor 1 according to an embodiment may include: a case 100 having an opening formed at one side thereof; a cover 200 provided on the housing 100; a rotor 300 coupled to the shaft 500; a stator 400 disposed in the case 100; a shaft 500 configured to rotate together with the rotor 300; a bus bar 600 disposed above the stator 400; and a sensor part 700 configured to detect rotation of the rotor 300.

The electric machine 1 may be used in a clutch actuator.

Alternatively, the motor 1 may be a motor used in an Electric Power Steering (EPS) system. The EPS system assists a steering force using a driving force of a motor to ensure steering stability and quickly provide a restoring force so that a driver can safely drive a vehicle.

The housing 100 and the cover 200 may form the exterior of the motor 1. In addition, an accommodation space may be formed by coupling the case 100 and the cover 200. Accordingly, as shown in fig. 1, the rotor 300, the stator 400, the shaft 500, the bus bar 600, the sensor part 700, and the like may be disposed in the accommodation space. In this case, the shaft 500 is rotatably disposed in the receiving space. Accordingly, the motor 1 may further include bearings 10 disposed at upper and lower portions of the shaft 500.

The case 100 may be formed in a cylindrical shape. In addition, the case 100 may accommodate the rotor 300, the stator 400, and the like therein. In this case, the shape or material of the housing 100 may be variously changed. For example, the case 100 may be formed of a metal material that well withstands even high temperatures.

The cover 200 may be disposed on an open surface of the case 100, i.e., an upper portion of the case 100, to cover the opening of the case 100.

The rotor 300 may be disposed inside the stator 400, and the shaft 500 may be coupled to a central portion of the rotor 300 in a press-fit manner. In this case, the rotor 300 may be rotatably provided in the stator 400. Here, the term "inner" may mean a direction toward the center C in a radial direction, and the term "outer" may mean a direction opposite to the "inner".

Fig. 2 is a perspective view illustrating a rotor of a motor according to an embodiment. Fig. 3 is a side view illustrating a rotor of a motor according to an embodiment.

Referring to fig. 2 and 3, the rotor 300 may include a rotor core 310 and a plurality of magnets 320 disposed on an outer circumferential surface of the rotor core 310. In addition, the rotor 300 may further include: a first can 330 disposed on an upper portion of the rotor core 310 to which the magnet 320 is attached; and a second can 340 disposed on a lower portion of the rotor core 310 to which the magnets 320 are attached.

Fig. 4 is a perspective view illustrating a rotor core and a magnet of a rotor of a motor according to an embodiment, fig. 5 is a plan view illustrating the rotor core and the magnet of the rotor of the motor according to the embodiment, and fig. 6 is an enlarged view illustrating a region a of fig. 5.

Referring to fig. 4 to 6, a plurality of magnets 320 may be disposed on the outer circumferential surface of the rotor core 310 in the circumferential direction.

As shown in fig. 4 and 5, a plurality of magnets 320 may be provided on the outer circumferential surface of the rotor core 310 to be spaced apart from each other at a prescribed interval. In this case, the magnet 320 may be referred to as a rotor magnet or a driving magnet.

The rotor core 310 may be formed in a stack of a plurality of round thin steel plates or in a single cylinder. A hole coupled with the shaft 500 may be formed in the center C of the rotor core 310.

Fig. 7 is a perspective view illustrating a rotor core of a rotor provided in a motor according to an embodiment, fig. 8 is a plan view illustrating the rotor core of the rotor provided in the motor according to the embodiment, fig. 9 is a sectional view illustrating the rotor core of the rotor provided in the motor according to the embodiment, and fig. 10 is an enlarged view illustrating a region B of fig. 9.

Referring to fig. 7 to 10, the rotor core 310 may include a main body 311, a protrusion 312 obliquely inwardly protruding at a prescribed angle from an inner circumferential surface 311a of the main body 311, and a plurality of guides 313 protruding outwardly from an outer circumferential surface 311b of the main body 311. In addition, the rotor core 310 may further include a hole 314 formed in the body 311. In addition, the rotor core 310 may further include a groove 315 concavely formed in the outer circumferential surface 311b of the main body 311. In this case, the body 311, the protrusion 312, and the guide 313 may be integrally formed.

The body 311 may be formed in a tubular shape. For example, the body 311 may be formed in a ring shape, a circular shape, or a donut shape (donut shape) when viewed from above. In addition, a hole may be formed in a central portion of the body 311 in order to arrange the shaft 500.

The protrusion 312 may be formed to protrude obliquely inward at a prescribed angle from the inner circumferential surface 311a of the body 311. As shown in fig. 5, since the protrusion 312 protrudes obliquely at a predetermined angle, a predetermined gap G1 can be formed between the inner peripheral surface 311a of the body 311 and the end of the protrusion 312. In this case, the gap G1 formed between the inner peripheral surface 311a of the main body 311 and the end of the protruding portion 312 may be referred to as a first gap.

Accordingly, when the shaft 500 is disposed in the hole of the body 311, the protrusion 312 may contact the outer circumferential surface of the shaft 500. In this case, since the shaft 500 is coupled to the main body 311 in a press-fit manner, the gap G1 can be reduced. For example, in the case where the rotor core 310 is coupled to the shaft 500 in a press-fit manner, since the radius of a circle, which is an imaginary circle connecting the ends of the protrusions 312, is smaller than the radius of the shaft 500, the gap G1 may be reduced when the shaft 500 is press-fitted to the rotor core 310.

Accordingly, when the shaft 500 is press-fitted and coupled to the hole formed in the rotor core 310, although the press-fitting force is applied to the rotor core 310 in the radial direction, the gap G1 formed due to the protrusion 312 performs a buffering function to minimize the amount of change in the outer circumferential surface of the rotor core 310, thereby buffering the press-fitting force applied to the magnet 320 attached to the outer circumferential surface of the rotor core 310. Accordingly, the protrusion 312 may minimize an amount of change in the outer diameter of the rotor core 310 due to the press-fitting force to prevent separation of the magnet 320.

As shown in fig. 7 and 8, the protrusion 312 may be provided as a first protrusion 312a and a second protrusion 312 b. However, the projection 312 is not necessarily limited thereto. For example, the protrusion 312 may be provided as any one of the first and second protrusions 312a and 312 b.

However, in consideration of the coupling force between the rotor core 310 and the shaft 500, the protrusion 312 may be provided as a first protrusion 312a and a second protrusion 312b, ends of the first protrusion 312a and the second protrusion 312b protruding obliquely in a direction spaced apart from each other in the circumferential direction.

Referring to fig. 8 and 10, each of the first and second protrusions 312a and 312b may obliquely protrude from the inner circumferential surface 311a of the body 311 at a prescribed angle θ. For example, each of the first and second protrusions 312a and 312b may form a prescribed angle θ based on an imaginary line L passing through the center C of the rotor core 310 in the radial direction.

In this case, the ends of the first and second protrusions 312a and 312b may be formed to protrude in directions spaced apart from each other in the circumferential direction. For example, the first and second protrusions 312a and 312b may protrude obliquely in different directions in the circumferential direction. In this case, the first and second protrusions 312a and 312b may be symmetrically disposed based on the line L.

Referring to fig. 6, an end of the first protrusion 312a and an end of the second protrusion 312b may form a first angle θ 1 based on the center C of the rotor core 310, one corner and the other corner of the magnet 320 may form a second angle θ 2 based on the center C of the rotor core 310, and the first angle θ 1 may be smaller than the second angle θ 2. In this case, the first angle θ 1 may be arranged within the second angle θ 2.

In this case, an imaginary line L1 connecting the center C of the rotor core 310 and the ends of the first and second protrusions 312a and 312b may be formed, and the first angle θ 1 may be an acute angle between the lines L1. In addition, an imaginary line L2 connecting the center C of the rotor core 310 and one corner and the other corner of the magnet 320 may be formed, and the second angle θ 2 may be an acute angle between the lines L2.

In this case, the center C1 of the magnet 320 may be disposed on an imaginary line L passing through the center C of the rotor core 310 in the radial direction, and the first and second protrusions 312a and 312b may be symmetrically disposed based on the line L. The center C2 of the protruding portion 312 where the first protrusion 312a and the second protrusion 312b are formed may be provided on the line L. In this case, the center C2 of the protrusion 312 may be the center of a region where the inner circumferential surface 311a of the main body 311 meets the protrusion 312 in the circumferential direction.

That is, the center C1 of the magnet 320 and the center C2 of the protrusion 312 may be disposed on the same radius line L. In this case, as shown in fig. 5, the width W1 of the protrusion 312 is smaller than the width W2 of the magnet 320. For example, the protrusion 312 may be disposed to overlap with one portion of the magnet 320 when viewed in the radial direction. Therefore, the press-fit force applied to the magnet 320 in the radial direction by the shaft 500 can be buffered by the protrusion 312 and transmitted to the magnet 320.

Accordingly, the protrusion 312 of the rotor 300 allows the shaft 500 to be coupled to the rotor core 210 in a press-fit manner, and also buffers the press-fit force to prevent separation of the magnets 320.

The protrusion 312 may be formed to have a predetermined height in the axial direction based on the lower surface 311c of the body 311. In this case, the height of the protrusion 312 in the axial direction may be smaller than the height of the body 311 in the axial direction, so that the amount of contact between the protrusion 312 and the shaft 500 may be reduced.

Referring to fig. 9, the height H1 of the protrusion 312 may be smaller than the height H2 of the body 311 in the axial direction based on the lower surface 311c of the body 311. In this case, the height H2 of the body 311 may be 1.9 to 2.0 times the height H1 of the protrusion 312. Specifically, the height H2 of the body 311 may be 1.93 times the height H1 of the protrusion 312. In this case, the height H1 of the protrusion 312 may be referred to as a first height, and the height H2 of the body 311 may be referred to as a second height.

Accordingly, the contact between the protrusion 312 and the shaft 500 may be minimized due to the protrusion 312 formed to have the first height H1, so that the press-fitting force applied to the rotor core 310 may be minimized. In addition, since the second height H2 is formed to be 1.9 to 2.0 times the first height H1, it is possible to prevent inclination of the shaft 500 due to a force applied to the shaft 500 in a radial direction.

On the other hand, the ends of the first and second protrusions 312a and 312b may be rounded in consideration of contact with the shaft 500. Therefore, the ends of the first and second protrusions 312a and 312b may make line contact with the shaft 500 in the axial direction.

For example, since each of the end portions of the first and second protrusions 312a and 312b may be formed to include a curved surface having a prescribed curvature, the end portions of the first and second protrusions 312a and 312b may be in line contact with the shaft 500 in the axial direction.

The rotor core 310 may include a guide 313 extending and protruding outward from the outer circumferential surface 311b of the main body 311. The guide 313 may be integrally formed with the rotor core 310. In this case, the guide 313 may be formed from the lower surface 311c of the body 311 to the upper surface 311d of the body 311 in the axial direction.

The guide 313 guides the arrangement of the magnets 320. Accordingly, the magnet 320 may be disposed between the guide members 313. In this case, the protruding length of the guide 313 in the radial direction based on the outer circumferential surface 311b of the rotor core 310 is smaller than the thickness of the magnet 320 in the radial direction.

In this case, an example is shown in which the rotor core 310 includes the guide 313, but the rotor core 310 is not necessarily limited thereto. For example, the guide 313 may be removed from the rotor core 310. However, in the case where the guide 313 is formed on the rotor core 310, since the area to which the adhesive member is applied is increased, the fixing force of the magnet 320 may be increased.

The hole 314 may be formed in the body 311. As shown in fig. 9, a hole 314 may be formed through the body 311 in the axial direction. For example, the hole 314 may be formed from the lower surface 311c of the body 311 to the upper surface 311d of the body 311 in the axial direction.

The hole 314 may be disposed between the protrusion 312 and the magnet 320 in a radial direction.

In addition, the hole 314 may be formed as a long hole extending in the circumferential direction when viewed from above.

When viewed from above, one corner and the other corner of the hole 314 may form a third angle θ 3 based on the center C of the rotor core 310. Therefore, the first angle θ 1 may be greater than the third angle θ 3. That is, the third angle θ 3 may be smaller than the first angle θ 1, and the third angle θ 3 may be disposed within the first angle θ 1.

In this case, an imaginary line L3 connecting the center C of the rotor core 310 and one corner and the other corner of the hole 314 may be formed, and the third angle θ 3 may be an acute angle between the lines L3.

On the other hand, the center C3 of the hole 314 may be disposed on an imaginary line L connecting the center C1 of the magnet and the center C of the rotor core 310. In this case, the center C2 of the protrusion 312 may also be disposed on the imaginary line L. In this case, the center C2 of the protrusion 312 may be the center of a region where the inner circumferential surface 311a of the main body 311 meets the protrusion 312 in the circumferential direction. For example, the center C2 of the protrusion 312 may be the center of the protrusion 312 between one point P and another point P in the circumferential direction where the inner peripheral surface 311a of the body 311 meets the protrusion 312.

In addition, the width W3 of the hole 314 may be less than the width W1 of the protrusion 312. In this case, the width W3 of the hole 314 may be the same as the width between one point P and another point P of the protrusion 312 where the inner circumferential surface 311a of the body 311 meets the protrusion 312. Thus, press-fit forces may be transmitted in a radial direction to the aperture 314, but buffered through the aperture 314.

In addition, the hole 314 may have a prescribed width in the radial direction. The width of the hole 314 in the radial direction may be adjusted in consideration of the strength of the body 311 and the buffering force against the press-fitting force.

The groove 315 may be formed concavely inward from the outer circumferential surface 311b of the body 311. Accordingly, the inner surface 315a may be formed to be spaced inward from the outer circumferential surface 311b of the body 311. In this case, the groove 315 may be formed from the lower surface 311c of the body 311 to the upper surface 311d of the body 311 in the axial direction.

The groove 315 may be disposed outside the hole 314 in the radial direction.

When viewed from above, one corner and the other corner of the groove 315 may form a fourth angle θ 4 based on the center C of the rotor core 310. Therefore, the first angle θ 1 may be smaller than the fourth angle θ 4. In this case, the first angle θ 1 may be disposed within the fourth angle θ 4. In this case, an imaginary line L4 connecting the center C of the rotor core 310 and one corner and the other corner of the groove 315 may be formed, and the fourth angle θ 4 may be an acute angle between the line L4.

On the other hand, the center C4 of the groove 315 may be disposed on an imaginary line L connecting the center C1 of the magnet and the center C of the rotor core 310.

In addition, the width W4 of the groove 315 may be greater than the width W1 of the protrusion 312 or the width W3 of the aperture 314. However, the width W4 of the groove 315 may be less than the width W2 of the magnet 320. Thus, press-fit forces may be transferred to the groove 315 in a radial direction, but buffered by the groove 315.

On the other hand, an adhesive member (not shown) may be disposed in the groove 315.

The magnets 320 may be disposed on the outer circumferential surface 311b of the rotor core 310 and spaced apart from each other at a prescribed interval. In this case, the magnet 320 may be attached to the outer circumferential surface 311b of the rotor core 310 using an adhesive member such as an adhesive. In addition, since the adhesive member may fill the groove 315 and be cured, the fixing force of the magnet 320 in the circumferential direction may be improved.

Referring to fig. 5, since the groove 315 is formed in the outer circumferential surface 331b of the body 311, a prescribed gap G2 may be formed between the inner side surface 321 of the magnet 320 and the inner surface 315a of the groove 315. In this case, G2 may be referred to as a second gap.

Accordingly, when the shaft 500 is coupled to the main body 311 in a press-fit manner, the gap G2 may be reduced. Therefore, the press-fitting force applied to the magnet 320 can be buffered by the gap G2. In addition, due to the gap G2, the amount of change in the outer peripheral surface 331b of the main body 311 can be minimized.

Fig. 11 is a view showing a rotor of a motor according to a comparative example. Fig. 12 is a graph showing the amount of change in the outer diameter of the rotor core of the motor according to the comparative example and the amount of change in the outer diameter of the rotor core provided in the motor according to the embodiment.

Referring to fig. 11, a rotor provided in the motor 2 according to the comparative example may include a rotor core 310a and magnets 320 provided on an outer circumferential surface of the rotor core 310 a.

When comparing the rotor provided in the motor 2 according to the comparative example with the rotor 300 of the motor 1 according to the embodiment, the shape of the protrusion 312c and the shape of the hole 314a of the motor 2 according to the comparative example are different from those of the motor 1 according to the embodiment. For example, there are differences in that the protrusion 312c of the motor 2 according to the comparative example cannot buffer the press-fitting force generated when the shaft 500 is press-fitted thereto because it has a quadrangular shape, and in that the hole 314a has a circular shape and size different from those of the hole 314 of the motor 1 according to the embodiment.

As shown in fig. 12, it can be seen that there is a difference in the amount of change in the outer diameter of the rotor core due to the press-fitting force generated when the shaft 500 is press-fitted to the rotor core. That is, in the rotor core 310 of the motor 1, the amount of change in the outer diameter of the rotor core 310 is further reduced due to the protrusion 312 and the hole 314, so that the stress applied to the magnet 320 can be further buffered.

In addition, in the rotor core 310 of the motor 1, since the groove 315 is provided in addition to the protrusion 312 and the hole 314, the amount of change in the outer diameter of the rotor core 310 due to the press-fitting of the shaft 500 is further reduced, so that the stress applied to the magnet 320 can be further reduced. Accordingly, the magnet 320 may be prevented from being separated from the rotor core 310.

The first and second tanks 330 and 340 may protect the rotor core 310 and the magnets 320 from external impacts or physical or chemical stimuli, and may prevent foreign substances from being introduced into the rotor core 310 and the magnets 320.

In addition, the first and second cans 330 and 340 prevent the magnet 320 from being separated from the rotor core 310.

Each of the first and second cans 330 and 340 may be formed in a cup shape having a hole formed in a central portion thereof and disposed to cover one of upper and lower portions of the rotor core 310 to which the magnet 320 is attached. In this case, the end of the first can 330 and the end of the second can 340 may be disposed to be spaced apart from each other in the axial direction. In this case, the name "can" may be referred to as a lid. Accordingly, the first can 330 may be referred to as a first cap and the second can 340 may be referred to as a second cap.

In this case, the first and second cans 330 and 340 may be formed in the same shape. Accordingly, since the first and second tanks 330 and 340 can be used interchangeably, the production cost thereof can be minimized. However, the material of the second can 340 may be different from that of the first can 330 in consideration of the position of the protrusion 312. Alternatively, the strength of the second canister 340 may be greater than that of the first canister 330 in the radial direction in consideration of the position of the protrusion 312. Accordingly, the thickness of the second canister 340 in the radial direction may be greater than the thickness of the first canister 330 in the radial direction.

On the other hand, the second canister 340 may be disposed to overlap the protrusion 312 in the radial direction. In this case, the second can 340 may support the outer side 322 of the magnet 320. Therefore, even when the press-fitting force due to the press-fitting of the shaft 500 is transmitted through the protrusion 312 in the radial direction and applied to the magnet 320, the separation of the magnet 320 can be prevented by the second can 340.

The stator 400 may be disposed inside the case 100. In this case, the stator 400 may be supported by the inner circumferential surface of the case 100. Further, the stator 400 is disposed outside the rotor 300. That is, the rotor 300 may be disposed inside the stator 400.

Referring to fig. 1, the stator 400 may include a stator core 410, an insulator 420 disposed on the stator core 410, and a coil 430 wound around the insulator 420.

A coil 430 configured to generate a rotating magnetic field may be wound around the stator core 410. In this case, the stator core 410 may be formed as one core, or may be formed by coupling a plurality of separate cores.

The stator core 410 may be formed in the form of a stack of a plurality of thin steel plates, but is not necessarily limited thereto. For example, the stator core 410 may also be formed as a single product.

The stator core 410 may include a yoke (not shown) having a cylindrical shape and a plurality of teeth (not shown) protruding from the yoke in a radial direction. In addition, the coil 430 may be wound around the teeth.

The insulator 420 insulates the stator core 410 from the coil 430. Accordingly, the insulator 420 may be disposed between the stator core 410 and the coil 430.

Accordingly, the coil 430 may be wound around the stator core 410 on which the insulator 420 is disposed.

The shaft 500 may be rotatably disposed in the housing 100 by a bearing 10. Further, the shaft 500 may rotate together with the rotation of the rotor 300.

The bus bar 600 may be disposed on the stator 400.

In addition, the bus bar 600 may be electrically connected to the coil 430 of the stator 400.

The bus bar 600 may include a bus bar main body (not shown) and a plurality of terminals (not shown) provided in the bus bar main body. In this case, the bus bar body may be a molded product formed through an injection molding process. In addition, each terminal may be electrically connected to the coil 430 of the stator 400.

The sensor part 700 may detect the magnetic force of a sensing magnet installed to be rotatable with the rotation of the rotor 300 to check the current position of the rotor 300, thereby detecting the rotation of the shaft 500.

The sensor part 700 may include a sensing magnet assembly 710 and a Printed Circuit Board (PCB) 720.

The sensing magnet assembly 710 is coupled to the shaft 500 to be in linkage with the rotor 300 to detect the position of the rotor 300. In this case, the sensing magnet assembly 710 may include a sensing magnet and a sensing plate.

The sensing magnet may include: a main magnet disposed near a hole forming an inner circumferential surface in a circumferential direction; and a sub-magnet disposed at an edge thereof. The main magnet may be arranged similarly to the driving magnet inserted into the rotor 300 of the motor. The secondary magnets are further subdivided compared to the primary magnets such that the number of poles of the secondary magnets is greater than the number of poles of the primary magnets. Therefore, by the sub-magnet, the rotation angle can be divided and measured more finely, and the motor can be driven more smoothly.

The sensing plate may be formed of a metal material having a disc shape. The sensing magnet may be coupled to an upper surface of the sensing plate. Additionally, a sense plate may be coupled to the shaft 500. In this case, a hole through which the shaft 500 passes may be formed in the sensing plate.

A sensor configured to detect the magnetic force of the sensing magnet may be disposed on the PCB 720. In this case, a Hall integrated circuit (Hall IC) may be provided as the sensor. In addition, the sensor may detect changes in the N and S poles of the sensing magnet 610 to generate a sensing signal.

Although the present invention has been described with reference to exemplary embodiments thereof, it will be understood by those skilled in the art that various changes in form and details may be made therein without departing from the spirit and scope of the invention as defined by the appended claims.

< description of reference numerals >

1: the motor 10: bearing assembly

100: the housing 200: cover

300: the rotor 310: rotor core

311: the main body 312: projection part

313: the guide 314: hole(s)

315: groove 320: first tank

330: second tank 400: stator

410: stator core 430: coil

500: shaft 600: bus bar

700: sensor unit