KR102159798B1 - Motor of outer rotor type - Google Patents

Abstract

The present invention relates to an outer rotor type motor.
The outer rotor type motor according to the embodiment of the present invention includes first and second back yokes made of different materials. The first back yoke is configured integrally with the rotor frame. Since the first back yoke and the rotor frame are made of steel, it is possible to reduce material cost and increase the reliability of the motor. The second back yoke may be made of an electrical steel sheet, and thus performance of a magnetic circuit may be improved.

Description

{Motor of outer rotor type}

The present invention relates to an outer rotor type motor.

In general, an outer rotor type motor has a stator on which a coil is wound, and a rotor that is installed outside the stator and rotates by a rotating magnetic field formed when power is applied to the coil, and is provided with a magnet, and inside the rotor. It may include a rotating shaft that is installed and rotates simultaneously with the rotor when the rotor rotates.

The rotor further includes a back yoke forming a magnetic circuit, and the magnet may be installed on an inner circumferential surface of the back yoke. The back yoke may be made of an electrical steel plate or a steel material.

According to the prior art, when the back yoke is composed of an electric steel sheet, the loss of the rotor can be reduced and motor performance can be improved, while there is a disadvantage in that the material cost is increased. In addition, since the back yoke of the electrical steel sheet has a ring shape and is configured to be supported by the rotor frame, the outer diameter of the motor increases, and there is a problem that it may be scattered to the outside when the rotor rotates.

On the other hand, when the back yoke is made of a steel material, there is an advantage in that the material cost is low. In addition, the steel back yoke is integrally configured with the rotor frame, so that there is no fear of a scattering problem of the rotor. However, the steel back yoke has a problem in that the loss of the rotor increases and the motor performance decreases.

In connection with a conventional outer rotor type motor, the following patents have been disclosed.

1. Publication number (published date): Patent Publication 10-2009-0055029 (June 1, 2009)

2. Title of invention: Outer rotor motor and its manufacturing method

In order to prevent the above problems, an object of the present invention is to provide an outer rotor type motor capable of improving motor performance and reducing material cost by configuring a plurality of back yoke materials.

In particular, an object of the present invention is to provide an outer rotor type motor capable of reducing rotor loss by disposing back yokes of different materials according to the strong magnetic flux region and the weak magnetic flux region of the rotor.

For example, in the ferromagnetic flux region of the rotor, a back yoke made of an electrical steel sheet having excellent performance may be disposed in consideration of a relatively large loss of the rotor. Further, an object of the present invention is to provide an outer rotor type motor in which an inexpensive steel back yoke is disposed even though performance is slightly degraded in consideration of the fact that the loss of the rotor is relatively small in the weak magnetic flux region of the rotor.

In addition, the rotor frame and the steel back yoke are integrally configured to prevent the rotor from being separated (scattered) to the outside during the rotation of the rotor and to reduce the outer diameter of the motor, providing an outer rotor type motor. It is aimed at.

In addition, by dividing and arranging the back yoke made of electrical steel sheet on the outer circumference of the rotor frame integrally formed with the steel back yoke, the back yoke made of electrical steel sheet is selectively arranged in the strong magnetic flux region of the rotor to improve motor performance. An object of the present invention is to provide an outer rotor type motor that can reduce material cost while maintaining.

In particular, it provides an outer rotor type motor that can arrange a back yoke made of steel material in an area corresponding to 10-20% of the magnet's both ends, and an electrical steel back yoke in the rest area. It aims to do.

In order to solve the above problems, the outer rotor type motor according to the embodiment of the present invention includes first and second back yokes made of different materials.

The first back yoke is configured integrally with the rotor frame.

Since the first back yoke and the rotor frame are made of steel, it is possible to reduce material cost and increase the reliability of the motor.

The second back yoke may be made of an electrical steel sheet, and thus performance of a magnetic circuit may be improved.

The first back yoke may support a plurality of second back yokes.

The first back yoke includes an intermediate connecting portion provided between the plurality of second back yokes.

The motor includes a rotating shaft, a plurality of magnets installed on an inner circumferential surface of the rotor frame, and a stator core disposed inside the plurality of magnets.

The motor further includes a body portion disposed inside the stator core and through which the rotation shaft passes.

The motor further includes a plurality of windings extending radially from the stator core and winding a coil.

The rotor frame may further include an outer peripheral surface portion extending in an axial direction from an outer peripheral surface of the shaft coupling portion and formed to be rounded in a circumferential direction, and may support the magnet.

A yoke coupling portion to which the second back yoke is coupled is formed on the outer peripheral surface portion.

The yoke coupling portion includes a through hole.

A plurality of second back yokes are provided, and the plurality of second back yokes are arranged in a circumferential direction, so that it is easy to form a magnetic circuit.

The second back yoke may have a square plate shape.

First and second extension lines (ℓ1, ℓ2) extending from the center (C) of the rotation shaft toward both ends of the magnet are defined, and a first extending from the center (C) of the rotation shaft toward both ends of the intermediate connection part. When defined as 3,4 extension lines (ℓ3,ℓ4), the central angle formed by the third and fourth extension lines (ℓ3,ℓ4) is 10 to 20% of the center angle of the first and second extension lines (ℓ1,ℓ2). Is formed in a range.

The plurality of magnets include an 8-pole magnet, and the center angles of the first and second extension lines ℓ1 and ℓ2 form 45°.

When defining a fifth extension line (ℓ5) passing through the center of the gap between the plurality of magnets from the center (C) of the rotation shaft, the fifth extension line (ℓ5) may be configured to pass through the second back yoke.

When defining a sixth extension line (ℓ5) passing through the center of the magnet from the center (C) of the rotation axis, the sixth extension line (ℓ6) may be configured to pass through the intermediate connection.

The second back yoke may be composed of eight.

The body portion further includes a bearing that supports an outer peripheral surface of the rotation shaft.

According to an exemplary embodiment of the present invention, a plurality of materials of the back yoke may be used to improve motor performance and reduce material cost.

In particular, it is possible to reduce rotor loss by disposing back yokes of different materials according to the strong magnetic flux region and the weak magnetic flux region of the rotor.

In detail, in the ferromagnetic flux region of the rotor, a back yoke made of an electrical steel sheet having excellent performance may be disposed in consideration of a relatively large loss of the rotor. In addition, in consideration of the fact that the loss of the rotor is relatively small in the region of the weak magnetic flux of the rotor, by disposing a back yoke made of inexpensive steel even though the performance is slightly degraded, it is possible to improve the performance of the motor and reduce material cost.

In addition, since the rotor frame and the steel back yoke are integrally configured, the rotor can be prevented from being separated (scattered) to the outside during the rotation of the rotor and the outer diameter of the motor can be reduced.

In addition, by dividing and arranging the back yoke made of electrical steel sheet on the outer circumference of the rotor frame integrally formed with the steel back yoke, the back yoke made of electrical steel sheet is selectively arranged in the strong magnetic flux region of the rotor to improve motor performance. While maintaining, material cost can be reduced.

In particular, a steel back yoke is placed in the area corresponding to 10-20% of the magnet's both ends, and an electrical steel back yoke is placed in the remaining area to reduce the size of the motor while reducing the motor performance. It can be improved.

1 is a perspective view showing the configuration of a motor according to an embodiment of the present invention.
2 is an exploded perspective view of a motor according to an embodiment of the present invention.
3 is an exploded perspective view showing an exploded state of a back yoke made of an electrical steel sheet in a motor according to an embodiment of the present invention.
4 is a cross-sectional view taken along line IV-IV' of FIG. 1.
5 is a cross-sectional view taken along V-V' of FIG. 1.
6 is a cross-sectional view showing an arrangement of a back yoke according to an embodiment of the present invention.
7 is a view showing the flow of magnetic flux generated in the motor according to an embodiment of the present invention.

Hereinafter, some embodiments of the present invention will be described in detail through exemplary drawings. In adding reference numerals to elements of each drawing, it should be noted that the same elements are assigned the same numerals as possible even if they are indicated on different drawings. In addition, in describing an embodiment of the present invention, when it is determined that a detailed description of a related known configuration or function interferes with an understanding of the embodiment of the present invention, the detailed description thereof will be omitted.

In addition, in describing the constituent elements of an embodiment of the present invention, terms such as first, second, A, B, (a), and (b) may be used. These terms are only used to distinguish the component from other components, and the nature, order, or order of the component is not limited by the term. When a component is described as being "connected", "coupled" or "connected" to another component, that component may be directly connected or connected to that other component, but another component between each component It should be understood that may be “connected”, “coupled” or “connected”.

1 is a perspective view showing the configuration of a motor according to an embodiment of the present invention, FIG. 2 is an exploded perspective view of a motor according to an embodiment of the present invention, and FIG. 3 is an electrical steel sheet material in a motor according to an embodiment of the present invention It is an exploded perspective view showing an exploded state of the back yoke, and FIG. 4 is a cross-sectional view taken along IV-IV' of FIG. 1.

1 to 4, a motor 10 (hereinafter referred to as a motor) of an outer rotor tie according to an embodiment of the present invention includes a stator 220 and a rotor 100 disposed outside the stator 220. ) And a rotation shaft 150 coupled to the rotor 100.

Due to the interaction between the magnetic flux generated in the stator 220 and the magnetic flux generated in the rotor 100, torque may be generated in the motor 10. The magnetic flux of the stator 220 is generated by flowing current through the coil 225, and the magnetic flux of the rotor 100 is generated in the magnet 130 in which the N and S poles are alternately arranged.

In order for the magnetic flux generated in the rotor 100 to generate torque, a magnetic flux path flowing from the N pole to the S pole or from the S pole to the N pole is required. In order to generate such a path, that is, a bag for forming a magnetic circuit York may be provided.

In detail, the stator 220 includes stator cores 221 and 223 (hereinafter referred to as "cores") configured by stacking a plurality of plates and a coil 225 wound around the cores 221 and 223. The cores 221 and 223 include a ring-shaped core body 221 and a plurality of winding portions 223 extending radially from the core body 221.

The plurality of winding portions 223 may be arranged in a circumferential direction and may be configured to protrude in a radial direction from an outer peripheral surface of the core body 221. The coil 225 is wound around the plurality of winding portions 223, and a slot in which the wound coil 225 is positioned may be formed in a space between the plurality of winding portions 223.

The rotor 100 includes a rotor frame 110 and a plurality of magnets 130 installed inside the rotor frame 110.

The rotor frame 110 has a cylindrical shape with an empty inside. In detail, the rotor frame 110 includes a shaft coupling plate 111 to which the rotation shaft 150 is coupled.

The shaft coupling plate 111 has a shape of a disk, and a through hole 112 through which the rotation shaft 150 passes is formed in the center of the shaft coupling plate 111. The rotation shaft 150 may extend upward through the through hole 112 in the rotor frame 110. For example, the rotation shaft 150 may be press-fitted to the shaft coupling plate 111.

The rotor frame 110 includes an outer peripheral surface portion 115 extending in the axial direction from the shaft coupling plate 111 to form an outer peripheral surface of the rotor frame 110. The outer circumferential surface portion 115 may extend in a circumferential direction along the circumference of the shaft coupling plate 111.

The rotor frame 110 is understood as a frame in which a first back yoke is integrally formed. The rotor frame 110 and the first back yoke are made of steel. The rotor frame 110 may be referred to as a “back yoke integrated frame”.

That is, since the rotor frame 110 and the first back yoke are configured as one body, material cost can be reduced, and a phenomenon in which the rotor frame and the back yoke are separated during rotation of the motor can be prevented. Thus, the reliability of the motor can be improved.

A second back yoke 120 is coupled to the rotor frame 110. The second back yoke 120 may be made of an electrical steel sheet material. The second back yoke 120 made of the electrical steel sheet has excellent magnetic circuit formation performance, but is somewhat expensive, and it is difficult to be integrated with the rotor frame 110.

Accordingly, in the present embodiment, it is proposed to relatively reduce the amount of the second back yoke 120 and arrange it at a position that can help improve motor performance.

In detail, the second back yoke 120 is coupled to the outer peripheral surface portion 115 of the rotor frame 110. In addition, a plurality of second back yokes 120 may be provided, and a plurality of second back yokes 120 may be arranged to be spaced apart in a circumferential direction. As an example, eight second back yokes 120 may be provided (see FIG. 5 ).

The second back yoke 120 may have an approximately quadrangular plate shape, and may be configured to have a predetermined curvature so as to fit and fit the outer circumferential portion 115.

A yoke coupling portion 116 to which the second back yoke 120 is coupled is formed on the outer peripheral surface portion 115. A plurality of yoke coupling portions 116 are formed corresponding to the number of the second back yokes 120, and may be arranged spaced apart in a circumferential direction.

The outer peripheral surface portion 115 includes an intermediate connection portion 117 provided between the two nearest yoke coupling portions 116. The intermediate connection part 117 may constitute at least a part of the first back yoke.

The intermediate connection part 117 may function to support the second back yoke 120. In addition, the width of the intermediate connection part 117 in the circumferential direction may be determined to be an appropriate value in order to allow the second back yoke 120 to be disposed in the main magnetic flux section.

A plurality of magnets 130 are installed on the inner circumferential surface of the rotor frame 110 and may be disposed to surround the stator 220. In detail, the plurality of magnets 130 include first magnets 131 and second magnets 135 that are alternately disposed in a circumferential direction.

The first magnet 131 may constitute an N pole, and the second magnet 135 may constitute an S pole. For example, the plurality of magnets 130 may be composed of eight to form an eight-pole, and specifically, the first magnet 131 may be composed of four and the second magnet 135 may be composed of four.

When power is applied to the coil 225, the rotor frame 110 may rotate by a rotating magnetic field generated by changes in the electrodes of the magnet 130 and the electrodes of the cores 221 and 223. In addition, the rotation shaft 150 may be rotated together with the rotor frame 110.

The motor 10 further includes a body part 210 into which the rotation shaft 150 is inserted. The body portion 210 is injection-molded on the stator 220 and may be disposed inside the stator 220.

A shaft insertion part 212 into which the rotation shaft 150 is inserted is formed in the body part 210. The shaft insertion portion 212 is a portion formed by penetrating the body portion 210 in the vertical direction, and the body portion 210 may have a hollow shape by the shaft insertion portion 212. In addition, the shaft insertion portion 212 forms an inner peripheral surface of the hollow body portion 210 and may be disposed to surround the outer peripheral surface of the rotation shaft 150.

A bearing 170 may be installed on the body part 210. In detail, the body part 210 further includes a body recessed part 219 which is recessed radially outward from the shaft insertion part 212 to form a mounting space for the bearing 170. The body depression 219 may have a shape into which a ring-shaped bearing 170 can be inserted. In addition, the bearing 170 is disposed on the outer peripheral surface of the rotation shaft 150.

5 is a cross-sectional view taken along V-V' of FIG. 1, FIG. 6 is a cross-sectional view showing an arrangement of a back yoke according to an embodiment of the present invention, and FIG. 7 is generated in a motor according to an embodiment of the present invention. It is a diagram showing the flow of magnetic flux.

5 and 6, a plurality of magnets 130 according to an embodiment of the present invention is configured such that the first and second magnets 131 and 135 are alternately disposed in the circumferential direction. The first magnet 131 and the second magnet 135 are disposed adjacent to each other.

In detail, the first end 131a of the first magnet 131 and the second end 135a of the second magnet 135 are disposed adjacent to each other and configured to face each other. The magnetic flux generated by the magnet 130 passes through the first back yoke or the second back yoke 120 integrally formed with the rotor frame 110, and from the first end 131a to the second end 135a It may flow from the furnace or the second end 135a to the first end 131a.

The plurality of second back yokes 120 and the plurality of intermediate connecting portions 117 may be alternately disposed in the circumferential direction. In addition, the length of the second back yoke 120 in the circumferential direction may be longer than the length of the intermediate connecting portion 117 of the rotor frame 110 in the circumferential direction.

In detail, a virtual line extending from the center (C) of the rotation shaft 150 toward both ends of the magnet based on one of the magnets 130 is a first extension line (L1) and a first extension line, respectively. 2 When defined as the extension line (ℓ2), the angle formed by the first and second extension lines (ℓ1, L2) forms a first set angle (θ1).

For example, considering that the eight magnets 130 are arranged in the circumferential direction, the first set angle θ1 is formed to be about 45°. That is, the central angle of the magnet 130 is formed to be about 45°.

Meanwhile, virtual lines extending from the center C of the rotation shaft 150 toward both ends 117a and 117b of the intermediate connection part 117 are referred to as a third extension line (ℓ3) and a fourth extension line (ℓ4), respectively. When defined, the angle formed by the third and fourth extension lines ℓ3 and ℓ4 forms a second set angle θ2.

For example, the second set angle θ2 may be formed in a range of about 10 to 20% of the first set angle θ1. That is, the central angle of the intermediate connection part 117 may be formed in a range of about 4.5° to 9.0°.

Design allowance is provided by setting a range to the center angle of the intermediate connection part 117, that is, the center angle of the intermediate connection part 117, that is, the circumferential length of the second back yoke 120 This is because it can be determined according to the length in the center direction.

The position and length of the second back yoke 120 in the center direction may be determined according to the position and size of the strong magnetic flux region formed in the motor 10. In addition, the location and size of the strong magnetic flux region may be determined by a design factor of the motor, that is, the number of windings of the coil 225 and the size or amount of magnetic flux of the magnet 130.

In detail, the magnetic flux generated by the magnet 130 moves along the first and second back yokes. This magnetic flux determines the loss of the rotor 100, and the magnitude of the loss may vary depending on the material of the first and second back yokes.

Referring to FIG. 7, in the region through which the magnetic flux flows, a strong magnetic flux region or a main magnetic flux region (A1) where a large amount of magnetic flux is likely to cause a large loss, and a relatively small amount of the magnetic flux may cause less loss. A weak magnetic flux region A2 may be included.

In this embodiment, a second back yoke 120 made of an electric steel sheet having relatively excellent magnetic circuit performance is disposed in the strong magnetic flux region A1, and a first back yoke made of steel is disposed in the weak magnetic flux region A2. It characterized in that the arrangement.

When defining a fifth extension line (ℓ5) passing through the center of the gap between the first and second magnets 131 and 135 from the center (C) of the rotation shaft 150, the fifth extension line (ℓ5) is the strong magnetic flux region ( It is arranged to pass A1). Further, the fifth extension line ℓ5 may be configured to pass through the second back yoke 120 disposed in the strong magnetic flux region A1.

On the other hand, when defining a sixth extension line (ℓ5) passing through the center of the first magnet 131 or the second magnet 135 from the center (C) of the rotation shaft 150, the sixth extension line (ℓ6) Is disposed to pass through the weak magnetic flux region A2. In addition, the sixth extension line ℓ6 may be configured to pass through the first back yoke disposed in the weak magnetic flux region A2, that is, the intermediate connection part 117.

According to this configuration, each of the first and second back yokes composed of an electrical steel sheet and a steel material is provided, and among the first and second back yokes, the second back yoke 120 having relatively excellent magnetic circuit formation performance is The first back yoke, which is disposed in the magnetic flux region A1 and is inexpensive and has excellent reliability, is disposed in the weak magnetic flux region A2, thereby improving the performance and reliability of the motor.

10: motor 100: rotor
110: rotor frame 115: outer peripheral surface portion
116: yoke coupling portion 117: intermediate coupling portion
120: second back yoke 130: magnet
150: rotating shaft 210: body
220: stator 223: winding part
225: coil

Claims (14)

Rotating shaft;
A rotor frame having a shaft coupling portion coupled to the rotation shaft, integrally configured with the first back yoke, and made of steel;
A plurality of magnets installed on the inner circumferential surface of the rotor frame;
A stator core disposed inside the plurality of magnets;
A body portion disposed inside the stator core and through which the rotation shaft passes;
A plurality of windings extending in a radial direction from the stator core and winding a coil; And
It is provided on the rotor frame, and includes a plurality of second back yokes composed of an electrical steel plate of a material different from the first back yoke,
The rotor frame includes an outer peripheral surface portion extending in an axial direction from an outer peripheral surface of the shaft coupling portion and formed to be rounded in a circumferential direction,
On the outer peripheral surface portion,
A plurality of yoke coupling portions formed by opening portions of the outer circumferential portion to couple the plurality of second back yokes and arranged in a circumferential direction; And
An outer rotor type motor that is provided between the plurality of second back yokes to separate the plurality of second back yokes and includes an intermediate connection part constituting at least a portion of the first back yoke. delete delete delete delete delete delete The method of claim 1,
The second back yoke is an outer rotor type motor having a quadrangular plate shape. The method of claim 1,
Define first and second extension lines (ℓ1, ℓ2) extending from the center (C) of the rotation shaft toward both ends of the magnet,
When defined as the third and fourth extension lines (ℓ3, ℓ4) extending from the center (C) of the rotation shaft toward both ends of the intermediate connection part,
The outer rotor type motor is formed in a range of 10 to 20% of the center angle of the first and second extension lines ℓ1 and ℓ2. The method of claim 9,
The plurality of magnets include an 8-pole magnet,
An outer rotor type motor having a center angle of 45° of the first and second extension lines ℓ1 and ℓ2. The method of claim 1,
When defining a fifth extension line (ℓ5) passing through the center of the gap between the plurality of magnets from the center of the rotation shaft (C),
The fifth extension line (ℓ5) is an outer rotor type motor configured to pass through the second back yoke. The method of claim 1,
When defining a sixth extension line (ℓ5) passing through the center of the magnet from the center of the rotation shaft (C),
The sixth extension line (ℓ6) is an outer rotor type motor configured to pass through the intermediate connection portion. The method of claim 1,
The second back yoke is an outer rotor type motor comprising eight. The method of claim 13,
In the body part,
An outer rotor type motor further comprising a bearing supporting an outer peripheral surface of the rotation shaft.

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