KR20200021372A - Motor - Google Patents

Abstract

An embodiment of the present invention relates to a motor. The motor comprises: a shaft; a rotor in which the shaft is disposed in a center; and a stator disposed outside the rotor, wherein the rotor includes a rotor core and a plurality of magnets spaced apart from each other and disposed on an outer circumferential surface of the rotor core. The rotor core includes a body and a plurality of guides protruding outward from an outer circumferential surface of the body. The magnet disposed at a predetermined angle (θ) between the guides is formed in a rectangular shape. Accordingly, the motor can reduce a cogging torque by forming a skew using a single magnet.

Description

Motor {MOTOR}

Embodiments relate to a motor.

A motor is a device that obtains rotational force by converting electrical energy into mechanical energy, and is widely used in vehicles, household appliances, and industrial equipment.

The motor may include a housing, a shaft, a stator disposed inside the housing, a rotor installed on an outer circumferential surface of the shaft, and the like. Here, the stator of the motor induces electrical interaction with the rotor to induce rotation of the rotor. The shaft also rotates in accordance with the rotation of the rotor.

In particular, the motor can be used in a device for ensuring the stability of steering of an automobile. For example, the motor may be used in a motor for a vehicle such as an electronic power steering system (EPS).

The rotor is provided with a plurality of magnets, and according to the magnet installation method, an SPM (Surface Permanent Magnet) in which a magnet is attached to the surface of the rotor core and the rotor of an IPM (Interior Permanent Magnet) type in which the magnet is inserted into and coupled to the inside of the rotor core. ) Rotors of the type.

In the case of such a motor having an SPM type rotor, skew is formed in the magnet in order to reduce cogging torque.

To form the skew, the rotor separates the unit rotor core into two or three stages, and rotates the unit rotor core to have a constant step to form a step skew. However, there is a problem in that the number of magnets increases and the angle formed by the skew varies according to the attachment tolerance of the magnets.

Embodiments provide a motor capable of reducing cogging torque while reducing assembly tolerances by forming skew using a single magnet.

The problem to be solved by the present invention is not limited to the above-mentioned problem and other problems not mentioned herein will be clearly understood by those skilled in the art from the following description.

According to an embodiment, the object; A rotor in which the shaft is disposed in the center; And a stator disposed on an outer side of the rotor, wherein the rotor includes a rotor core and a plurality of magnets spaced apart from each other on an outer circumferential surface of the rotor core, and the rotor core extends outward from the body and the outer circumferential surface of the body. The magnet, which includes a plurality of protruding guides and is disposed at a predetermined angle θ between the guides, is achieved by a motor formed in a rectangular shape.

Here, one edge of the magnet may be in contact with any one of the guides, and the other edge of the magnet may be in contact with another neighboring guide.

The upper side of the magnet may be spaced apart from the upper surface of the body by a predetermined distance (D).

On the other hand, the stator includes a yoke and a plurality of teeth protruding in the radial direction from the yoke,

The angle θ may be obtained by 360 ° / (the least common multiple of the number of teeth and the number of magnets).

In addition, the angle θ may be equal to the angle formed between the upper surface of the body and the upper surface of the magnet.

에 의해 구해질 수 있다. Herein, when the length of the magnet is L and the width of the magnet is h, the separation distance a between the guides is

Can be obtained by

In addition, one side edge of the magnet may be arranged to protrude at a predetermined distance (D1) from the upper surface of the body.

에 의해 구해질 수 있다. Herein, when the length of the magnet is L1 and the width of the magnet is h, the separation distance a between the guides is

Can be obtained by

Meanwhile, 12 teeth may be provided and 8 magnets may be provided.

The motor according to the embodiment having the above configuration can reduce the cogging torque by forming a skew using a single magnet.

In addition, the use of a single magnet can reduce the number of magnets, and production costs can be reduced through parts and process simplification.

In addition, unlike the case of using the unit rotor core described above, since a single magnet that forms a skew is used, it is possible to prevent magnet loss between steps in the same overall length.

In addition, by implementing the same shape of the first can and the second can, it is possible to reduce the production cost of the can. In addition, separation of the magnet may be prevented by using the first can and the second can.

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

1 is a view showing a motor according to an embodiment,
2 is a view showing a line AA of FIG.
3 is a view showing the stator core of the stator disposed in the motor according to the embodiment,
4 is a perspective view illustrating a rotor of a motor according to an embodiment;
5 is a side view showing the rotor of the motor according to the embodiment,
6 is a plan view illustrating a rotor of a motor according to an embodiment;
7 is a side view showing another embodiment of a rotor disposed in a motor according to the embodiment;
8 is a view showing a can disposed in the rotor of the motor according to the embodiment.

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 described, but may be embodied in different forms, and within the technical idea of the present invention, one or more of the components may be selectively selected between the embodiments. Can be combined and substituted.

In addition, the terms (including technical and scientific terms) used in the embodiments of the present invention may be generally understood by those skilled in the art to which the present invention pertains, unless specifically defined and described. The terms commonly used, such as terms defined in advance, may be interpreted as meanings in consideration of the contextual meaning of the related art.

In addition, the terms used in the embodiments of the present invention are intended to describe the embodiments and are not intended to limit the present invention.

As used herein, the singular forms may also include the plural unless specifically stated otherwise, and may be combined as A, B, C when described as "at least one (or more than one) of A and B, C". It can include one or more of all possible combinations.

In addition, in describing the components of the embodiments of the present disclosure, terms such as first, second, A, B, (a), and (b) may be used.

These terms are only to distinguish the components from other components, and the terms are not limited to the nature, order, order, or the like of the components.

And when a component is described as being 'connected', 'coupled' or 'connected' to another component, the component is not only connected, coupled or connected directly to the other component, It may also include the case where the 'component' is 'connected', 'coupled' or 'connected' by another component between the other components.

In addition, when described as being formed or disposed on the "top" or "bottom" of each component, the top (bottom) or the bottom (bottom) is not only when two components are in direct contact with each other, but also one. It also includes a case where the above-described further components are formed or disposed between two components. In addition, when expressed as "up (up) or down (down)" may include the meaning of the down direction as well as the up direction based on one component.

Hereinafter, exemplary embodiments will be described in detail with reference to the accompanying drawings, and the same or corresponding components will be given the same reference numerals regardless of the reference numerals, and redundant description thereof will be omitted.

1 is a view showing a motor according to the embodiment, Figure 2 is a view showing a line A-A of FIG. In FIG. 1, the x direction means the axial direction and the y direction means the radial direction. And the axial direction and the radial direction are perpendicular to each other. Here, the axial direction may be a length direction of the shaft 500.

1 and 2, the motor 1 according to the embodiment is disposed inside the housing 100 having an opening formed at one side, a cover 200 disposed at an upper portion of the housing 100, and a housing 100. The bus is disposed on the stator 300, the rotor 400 coupled to the shaft 500, the shaft 500 rotating together with the rotor 400, and an upper side of the stator 300. It may include a sensor unit 700 for detecting the rotation of the bar 600 and the rotor 400. Here, the inner side may mean the direction of the center (C) and the outer side may mean a direction opposite to the inner side.

Such a motor 1 may be a motor used for EPS. The EPS (Electronic Power Steering System) assists the steering force by the driving force of the motor, thereby ensuring turning stability and providing fast resilience to enable the driver to drive safely.

The housing 100 and the cover 200 may form an outer shape of the motor 1. In addition, an accommodation space may be formed by combining the housing 100 and the cover 200. Accordingly, as shown in FIG. 1, the stator 300, the rotor 400, the shaft 500, the bus bar 600, the sensor unit 700, and the like may be disposed in the accommodation space. At this time, the shaft 500 is rotatably disposed in the accommodation space. Thus, the motor 1 may further include a bearing 10 disposed on the upper and lower portions of the shaft 500, respectively.

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

The cover 200 may be disposed on the opening surface of the housing 100, that is, the upper portion of the housing 100 to cover the opening of the housing 100.

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

1 and 2, the stator 300 may include a stator core 310, an insulator 320 disposed on the stator core 310, and a coil 330 wound around the insulator 320.

A coil 330 forming a rotating magnetic field may be wound around the stator core 310. Here, the stator core 310 may be composed of one core or a plurality of split cores may be combined.

The stator core 310 may be formed of a plurality of plates stacked in the form of a thin steel sheet, but is not necessarily limited thereto. For example, the stator core 310 may be formed as one single piece.

3 is a diagram illustrating a stator core of a stator disposed in a motor according to an embodiment.

Referring to FIG. 3, the stator core 310 may include a cylindrical yoke 311 and a plurality of teeth 312 protruding radially from the yoke 311. In addition, a coil 330 may be wound around the tooth 312.

The tooth 312 may be disposed to protrude from the yoke 311 toward the center C with respect to the radial direction (y direction). The teeth 312 may be spaced apart from each other on the inner circumferential surface of the yoke 311 along the circumferential direction. Accordingly, a slot S, which is a space in which the coil 330 can be wound, may be formed between each tooth 312. In this case, when eight magnets 420 are provided, the tooth 312 may be provided as twelve, but is not limited thereto.

On the other hand, the tooth 312 may be disposed to face the magnet 420 of the rotor 400. In this case, the inner surface of the tooth 312 may be spaced apart from the outer circumferential surface of the magnet 420 at a predetermined interval with respect to the radial direction.

The insulator 320 insulates the stator core 310 from the coil 330. Accordingly, the insulator 320 may be disposed between the stator core 310 and the coil 330.

Accordingly, the coil 330 may be wound around the stator core 310 in which the insulator 320 is disposed.

The rotor 400 may be disposed inside the stator 300, and the shaft 500 may be coupled to the center by a press-fit method. In this case, the rotor 400 may be rotatably disposed on the stator 300.

4 is a perspective view illustrating a rotor of the motor according to the embodiment, FIG. 5 is a side view illustrating the rotor of the motor according to the embodiment, and FIG. 6 is a plan view illustrating the rotor of the motor according to the embodiment.

4 and 6, the rotor 400 may include a rotor core 410 and a plurality of magnets 420 disposed along the circumferential direction on the outer circumferential surface of the rotor core 410. Here, the magnet 420 may be referred to as a rotor magnet or a drive magnet.

The rotor core 410 may be implemented in a stacked shape of a plurality of plates in the form of a circular thin steel sheet or may be implemented in a single cylindrical shape. In the center C of the rotor core 410, a hole to which the shaft 500 is coupled may be formed.

The rotor core 410 may include a body 411 to which the shaft 500 is coupled at the center and a guide 412 protruding outward from an outer circumferential surface of the body. Here, the body 411 and the guide 412 may be integrally formed.

The body 411 may be formed in a pipe shape or a cylindrical shape. For example, the body 411 may be formed in a planar ring, circle or donut shape. In addition, a hole may be formed in the center of the body 411 to arrange the shaft 500.

Guide 412 may guide the placement of magnet 420. Accordingly, the magnet 420 may be disposed between the guides 412. As shown in FIG. 5, the guide 412 may be formed along the axial direction from the upper surface 411a to the lower surface 411b of the body 411.

Here, the rotor core 410 includes a guide 412 as an example, but is not necessarily limited thereto. For example, the guide 412 in the rotor core 410 may be deleted. However, when the guide 412 is formed in the rotor core 410, since the area in which the adhesive member may be applied is expanded, the fixing force of the magnet 420 may be improved.

The magnets 420 may be disposed on the outer circumferential surface of the rotor core 410 to be spaced apart from each other at predetermined intervals. In this case, the magnet 420 may be attached to the outer circumferential surface of the body 411 of the rotor core 410 by using an adhesive member such as a bond. Here, eight magnets 420 may be provided.

The magnet 420 may be formed in a rectangular shape when viewed in the radial direction. For example, the magnet 420 may be formed in a rectangular shape having a length L and a predetermined width h. Here, the length L of the magnet 420 may be a lengthwise or axial length, and the width h of the magnet 420 may be a width relative to the width direction or the circumferential direction.

The magnet 420 may be disposed to be inclined to have a predetermined angle θ based on the axial direction of the shaft 500. As shown in FIG. 5, the magnet 420 may be inclined in the axial direction to have a predetermined angle θ with respect to the guide 412. Here, the angle θ may be called a skew angle.

In this case, the angle θ may be obtained by 360 ° / (the least common multiple of the number of teeth and the number of magnets). Here, the number of magnets 420 may be referred to as the number of poles of the magnets 420.

When the number of the teeth 312 is m and the number of the magnets 420 is n, the angle θ may be obtained by 360 ° / (minimum common multiple of m and n). At this time, the number of teeth 312 may be the same as the number of slots (S).

For example, when the number of slots S is 9 and the number of poles of the magnet 420 is 6, the LCM of 9 and 6 is 18. Thus, the angle θ is 20 ° which is 360 ° / 18.

In addition, when the number of slots, the number of slots S, is 12, and the number of poles of the magnet 420 is 8, the minimum common multiple of 12 and 8 is 24. Thus, the angle θ is 15 ° which is 360 ° / 24.

As shown in FIG. 5, the angle θ may be the same as the angle formed between the top surface 411a of the body 411 and the top surface 421 of the magnet 420.

In addition, the upper side of the magnet 420 may be spaced apart from the upper surface 411a of the body 411 by a predetermined distance D. As shown in FIG. 5, in consideration of the shape of the tooth 312 of the stator core 310 in the radial direction, one side edge of the top surface 421 of the magnet 420 is formed from the top surface 411a of the body 411. It may be spaced apart from the predetermined distance (D).

Meanwhile, one edge of the magnet 420 may be in contact with one of the guides 412, and the other edge of the magnet 420 may be in contact with another neighboring guide 412. Accordingly, the magnet 420 is prevented from flowing in the circumferential direction by the guide 412.

Referring to FIG. 5, the magnet 420 may be disposed between the first guide 412a and the second guide 412b. In this case, one edge P1 of the magnet 420 may contact the first guide 412a based on the circumferential direction, and the other edge P2 of the magnet 420 may contact the second guide 412b. .

Accordingly, when the separation distance between the guides 412 is a, a may be obtained by a1 + a2. Here, a1 may be a distance from the other edge of the magnet 420 to the neighboring guide 412 in the circumferential direction based on one side edge P1 of the magnet 420. Can be.

Therefore, here, since the magnet 420 is disposed to be inclined at a predetermined angle θ, the a can be obtained by the following equation.

∴

7 is a side view showing another embodiment of the rotor disposed in the motor according to the embodiment.

Referring to FIG. 7, one side edge of the magnet 420 may be disposed to protrude at a predetermined distance D1 from an upper surface of the body. Here, the magnet 420 may be formed in a rectangular shape having a length L1 and a predetermined width h. Accordingly, the length L1 of the magnet 420 according to another embodiment is larger than the length L of the magnet 420 according to the above-described embodiment.

Therefore, the a, which is the distance between the protrusions 412 in the circumferential direction, may be obtained by the following equation.

∴

8 is a view showing a can disposed in the rotor of the motor according to the embodiment.

Referring to FIG. 8, the rotor 400 may include a first can 430 disposed above the rotor core 410 to which the magnet 420 is attached and a lower portion of the rotor core 410 to which the magnet 420 is attached. The second can 440 may be further included.

The first can 430 and the second can 440 protects the rotor core 410 and the magnet 420 from external shocks, physical and chemical stimuli, and foreign substances flow into the rotor core 410 and the magnet 420. Can be prevented.

In addition, the first can 430 and the second can 440 may prevent the magnet 420 from being separated from the rotor core 410.

The first can 430 and the second can 440 may be formed in a cup shape having a hole formed at the center thereof, and are disposed to cover upper and lower portions of the rotor core 410 to which the magnet 420 is attached. In this case, an end portion of the first can 430 and an end portion of the second can 440 may be disposed to be spaced apart in the axial direction. Here, the name can can be called a cap. Accordingly, the first can 430 may be called a first cap, and the second can 440 may be called a second cap.

Here, the first can 430 and the second can 440 may be formed in the same shape. Accordingly, since the first can 430 and the second can 440 can be shared, production costs can be minimized.

The shaft 500 may be rotatably disposed in the housing 100 by the bearing 10. In addition, the shaft 500 may rotate together with the rotation of the rotor 400.

The bus bar 600 may be disposed above the stator 300.

In addition, the bus bar 600 may be electrically connected to the coil 330 of the stator 300.

The bus bar 600 may include a bus bar body (not shown) and a plurality of terminals (not shown) disposed inside the bus bar body. Here, the bus bar body may be a mold formed through injection molding. Each of the terminals may be electrically connected to the coil 330 of the stator 300.

The sensor unit 700 detects the magnetic force of the sensing magnet installed to be rotatable interlocked with the rotor 400 to detect the current position of the rotor 400 to detect the rotation of the shaft 500.

The sensor unit 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 cooperate with the rotor 400 to detect the position of the rotor 400. 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 in a circumferential direction adjacent to a hole forming an inner circumferential surface and a sub magnet formed at an edge thereof. The main magnet may be arranged in the same manner as the drive magnet inserted into the rotor 400 of the motor. The sub-magnet is more subdivided than the main magnet and consists of many poles. As a result, the sub-magnet makes it possible to divide and measure the rotation angle more precisely, and to induce driving of the motor more smoothly.

The sensing plate may be formed of a metal material of a disc shape. The sensing magnet may be coupled to the upper surface of the sensing plate. The sensing plate may be coupled to the shaft 500. Here, the sensing plate is formed with a hole through which the shaft 500 passes.

A sensor for detecting a magnetic force of the sensing magnet may be disposed on the printed circuit board 720. In this case, the sensor may be provided as a Hall IC. The sensor may generate a sensing signal by detecting a change in the N pole and the S pole of the sensing magnet.

Although described above with reference to a preferred embodiment of the present invention, those skilled in the art will be variously modified and changed within the scope of the invention without departing from the spirit and scope of the invention described in the claims below I can understand that you can.

1: motor
10: bearing
100: housing
200: cover
300: stator 330: coil
400: rotor
410: rotor core 411: body
412: Guide
420: magnet
430: first can 440: second can
500: shaft
600: busbar
700: sensor

Claims (9)

shaft;
A rotor in which the shaft is disposed in the center; And
It includes a stator disposed on the outside of the rotor,
The rotor includes a rotor core and a plurality of magnets spaced apart from each other on the outer peripheral surface of the rotor core,
The rotor core includes a body and a plurality of guides protruding outward from the outer peripheral surface of the body,
The magnet disposed at a predetermined angle (θ) between the guide is formed in a rectangular shape. The method of claim 1,
One side edge of the magnet in contact with the circumferential direction is in contact with any one of the guide, the other edge of the magnet is in contact with the other guide neighboring. The method of claim 2,
The upper side of the magnet is spaced apart from the upper surface of the body by a predetermined distance (D). The method of claim 1,
The stator includes a yoke and a plurality of teeth protruding radially from the yoke,
And the angle θ is obtained by 360 ° / (the least common multiple of the number of teeth and the number of magnets). The method of claim 4, wherein
The angle θ is the same as the angle formed by the upper surface of the body and the upper surface of the magnet. The method of claim 5,
When the length of the magnet is L and the width of the magnet is h,
The separation distance (a) between the guides

The motor obtained by The method of claim 5,
One side edge of the magnet is arranged to protrude at a predetermined distance (D1) from the upper surface of the body. The method of claim 7, wherein
When the length of the magnet is L1 and the width of the magnet is h,
The separation distance (a) between the guides

The motor obtained by The method of claim 4, wherein
The tooth is provided with twelve, the magnet is provided with eight.

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