KR102461471B1 - motor - Google Patents

Abstract

The present invention relates to motors, and more particularly to vernier motors.
According to an embodiment of the present invention, a rotor provided with a plurality of magnets along the circumferential direction; It includes a core, a tooth portion extending from the core to face the rotor, and two or more teeth (FMP, flux modulation pole) formed in the tooth portion and having an air gap with the rotor, formed by punching a magnetic steel plate being a stator core; And in the motor including a coil wound in the slot between the teeth and the teeth, a stator magnet is provided between the teeth and the stator magnet for the circumferential length (FMP pitch, β) of the teeth. A motor can be provided, characterized in that the ratio (α/β) of the circumferential length (stator pitch, α) of is 1.2 to 2.1.
According to an embodiment of the present invention, a three-phase motor for driving the drum of a washing machine may be provided.

Description

motor {motor}

The present invention relates to motors, and more particularly to vernier motors.

The motor refers to a device for transmitting the rotational force to the outside by rotating the rotor by electromagnetic interaction between the stator and the rotor. Here, the rotational force of the rotor drives the load through the rotation shaft.

The stator generally includes a stator core and a coil wound around the stator core. Accordingly, as a current flows in the coil, an electromagnetic force is generated.

The rotor is rotated by the electromagnetic force. In order to improve the performance of the motor, a rotor equipped with a permanent magnet (magnet) is provided. In such a motor, the rotor rotates due to the interaction between the electromagnetic force generated from the stator and the magnetic force of the magnet of the rotor.

1 shows a conventional motor. Such a motor may be a motor for driving a drum as a motor of a washing machine.

The motor 1 includes a rotor 10 and a stator 20 . For example, the rotor 10 may be rotatably provided outside the stator 20 in a radial direction. A gap G may be formed between the rotor 10 and the stator 20 in a radial direction. Through the gap G, the rotor 10 may rotate without contacting the stator 20 . The rotor 10 may be directly connected to a shaft that rotates the drum so that the rotor and the drum rotate together. This type is generally referred to as a direct drive (DD) method.

The rotor 10 may include a rotor core 11 and a magnet 14 . The rotor core may be formed of a magnetic material, and a magnet 14 may be mounted on a radially inner surface of the rotor core 11 . A plurality of the magnets 14 may be provided so as to have respective magnetic poles as permanent magnets. The magnet 12 magnetized to the S pole and the magnet 13 magnetized to the N pole may be alternately mounted along the circumferential direction. Accordingly, the number of such magnets 14 is equal to the number of magnetic poles of the rotor.

The stator 20 may include a stator core 21 , a tooth portion 22 protruding in a radial direction from the stator core, and teeth 23 provided at a radial end of the tooth portion 23 . The stator core 21 , the teeth 22 and the teeth 23 may be formed of the same magnetic material, and may be formed of a conductive steel plate.

A slot 24 is formed between the teeth 22 and the teeth 22, and a conductive wire is wound in the slot to form a coil.

For example, a radial distance between the teeth 23 and the magnet 14 may be referred to as a gap (G).

A conventional motor such as the motor shown in FIG. 1 has 40 rotor poles, 24 teeth, 8 stator poles, and 24 stator slots. That is, the number of teeth and the number of slots may be formed to be the same.

2 shows another conventional motor. The basic form is the same as in FIG. 1 . Therefore, redundant descriptions of the same items will be omitted.

The stator 20 shown in FIG. 2 is an example having two teeth 23 on one tooth portion 22 . Accordingly, the number of teeth corresponding to twice the number of teeth may be formed. In addition, a tooth gap 25 may be formed between the teeth 23 and the teeth 23 formed in one tooth portion 22 . The tooth gap 25 may be formed to have the same width in the circumferential direction of the teeth 23 .

A conventional motor such as the motor shown in FIG. 2 has 40 rotor poles, 24 teeth, 8 stator poles, and 12 stator slots. That is, the number of teeth and the number of slots are the same, and the number of teeth (FMP, flux modulation pole) may have twice the number of teeth.

Similarly, it can be seen that the motor shown in FIG. 2 can be applied to a motor that drives the drum of the washing machine, and the same rotor can be used except that the stator structure is different.

The conventional motors shown in FIGS. 1 and 2, particularly motors for washing machines, are driven by a permanent magnet provided in a rotor and electromagnetic force generated from a stator. The amount of current and voltage that can be provided through the coil of the stator is inevitably limited. Therefore, the magnitude of the electromagnetic force that can be provided through the stator or the output of the motor is inevitably limited.

In order to solve this problem, a vernier motor having a permanent magnet in the rotor may be provided. As an example of a vernier motor, there is a bar presented in Japanese Patent Application (Patent No. JP2013-005563, hereinafter referred to as "prior invention").

The permanent magnet provided in the stator may be detached by the attractive force generated between the permanent magnet provided in the rotor and the permanent magnet provided in the stator. In order to solve this problem, the prior invention proposes to form a non-magnetic holder for inserting a permanent magnet between the teeth and the teeth of the stator. That is, a structure for fixing the permanent magnet to the stator by molding the permanent magnet in the holder of the non-magnetic material is proposed.

Specifically, the prior invention proposes to manufacture a stator by insert-molding a stator core and a permanent magnet, which is a magnetic substance, and then a non-magnetic substance, which is a resin material, to surround the stator core and the permanent magnet.

Accordingly, in the prior invention, the material cost and processing cost of the motor are inevitably increased. This is because a complicated structure for forming the holder is inevitably added, which increases the material cost. In addition, additional processing is required after molding, which inevitably increases the manufacturing cost.

In particular, since the stator is manufactured by molding, the dispersion of errors during manufacturing is inevitably increased, thereby reducing reliability. And since the space occupied by the permanent magnet holder is additionally generated, the size of the entire stator is inevitably increased.

On the other hand, the conventional motor for driving the drum of a washing machine has a complicated structure and is not easy to manufacture because the number of slots is large. Therefore, there is a need to provide a simpler and easier to manufacture motor while satisfying the equivalent performance or higher.

An object of the present invention is to solve the problem of the above-described conventional motor, in particular, a vernier motor.

An object of the present invention is to provide a motor with a simple structure, suppression of additional material cost increase, and suppression of increase in motor size.

An object of the present invention is to provide a motor capable of mounting a permanent magnet on a stator in a simple and stable manner.

An object of the present invention is to provide a motor capable of directly inserting a permanent magnet into a stator core, which is a magnetic body, and structurally and very effectively preventing the permanent magnet from being separated.

An object of the present invention is to provide a motor capable of effectively preventing a permanent magnet inserted into a stator from being separated in a radial direction through an embodiment of the present invention.

An object of the present invention is to provide a motor that can effectively prevent permanent magnets vertically inserted into the stator from being separated in the vertical direction through insulators respectively coupled to the upper and lower portions of the stator core.

An object of the present invention is to provide a motor that provides maximum performance by optimizing the ratio between the teeth of the stator core and the pitch of the magnet mounted between the teeth.

Through an embodiment of the present invention, when a plurality of teeth are formed in one tooth, a motor providing maximum performance by optimizing a ratio between the width of the tooth and the width of the passage branched from the tooth to the tooth is provided. want to

An object of the present invention is to provide a motor for driving a washing machine drum that is easy to manufacture and has excellent performance.

In order to implement the above object, according to an embodiment of the present invention, a rotor provided with a plurality of magnets along the circumferential direction; It includes a core, a tooth portion extending from the core to face the rotor, and two or more teeth (FMP, flux modulation pole) formed in the tooth portion and having an air gap with the rotor, formed by punching a magnetic steel plate being a stator core; And in the motor including a coil wound in the slot between the teeth and the teeth, a stator magnet is provided between the teeth and the stator magnet for the circumferential length (FMP pitch, β) of the teeth. A motor can be provided, characterized in that the ratio (α/β) of the circumferential length (stator pitch, α) of is 1.2 to 2.1.

Preferably, the stator core is recessed in a radial direction between the teeth and a magnet mounting portion integrally formed with the stator core is formed.

The magnet mounting portion is preferably formed integrally with the stator core by punching the stator core.

For each of the teeth, three teeth may be formed and two stator magnets may be provided.

Preferably, β of the three teeth is equal to each other, and α of the two stator magnets is equal to each other.

In the motor, as the ratio (α/β) increases from 1.0, the back electromotive force and the efficiency tend to increase, and the torque ripple tends to increase after decreasing.

The motor, within the range of the ratio (α/β) of 1.2 to 2.1, has an efficiency of 105% or more and torque ripple compared to 100% of efficiency and 100% of torque ripple when the ratio (α/β) is 1.0 95% or less.

Preferably, the stator core includes a passage portion extending from the tooth portion in both circumferential directions and connected to the tooth portion.

It is preferable that the width Wt in the longitudinal direction of the teeth is greater than the width Wm in the longitudinal direction of the passage.

Preferably, the ratio (Wt/Wm) of the width Wt to the width Wm is 2.63 to 3.38.

The efficiency of the motor is preferably 85% or more within the range of the ratio (Wt/Wm) of 2.63 to 3.38.

The passage portion may be connected to the teeth after extending in the circumferential direction past the magnet mounting portion.

The passage portion may be connected to the teeth by extending in a diagonal shape having an angle greater than 90 degrees to the teeth.

In order to increase the width between the circumferential end of the magnet mounting portion and the passage portion, an edge portion of the magnet mounting portion may be formed to have an inclined surface.

The inclined surface is preferably formed to be parallel to the passage portion.

It is preferable that an edge of the stator magnet mounted on the magnet mounting unit has a chamfered surface corresponding to the inclined surface.

The magnet mounting portion may include a circumferential surface and a radial surface extending in a radial direction from both ends of the circumferential surface, respectively, and the inclined surface may be formed only between the circumferential surface and any one radial surface.

Preferably, the inclined surface is formed only at a corner portion further spaced apart from the tooth portion in the circumferential direction among both ends of the circumferential surface.

Preferably, the angle between the radial surface and the inclined surface is 59 degrees.

In order to implement the above object, according to an embodiment of the present invention, a rotor provided with a plurality of magnets along the circumferential direction; It includes a core, a tooth portion extending from the core to face the rotor, and two or more teeth (FMP, flux modulation pole) formed in the tooth portion and having an air gap with the rotor, formed by punching a magnetic steel plate being a stator core; And in the motor comprising a coil wound in the slot between the teeth and the teeth, a stator magnet is provided between the teeth and the teeth, the stator core extends in both circumferential directions from the teeth and the teeth and a passage portion to be connected, wherein a width (Wt) in the longitudinal direction of the tooth portion is greater than a width (Wm) in the longitudinal direction of the passage portion, and a ratio (Wt/) of the width (Wt) to the width (Wm) Wm) may be provided with a motor characterized in that it has 2.63 to 3.38.

In order to implement the above object, according to an embodiment of the present invention, a rotor provided with a plurality of magnets along the circumferential direction; It includes a core, a tooth portion extending from the core to face the rotor, and two or more teeth (FMP, flux modulation pole) formed in the tooth portion and having an air gap with the rotor, formed by punching a magnetic steel plate being a stator core; And in the motor comprising a coil wound in the slot between the teeth and the teeth,

A magnet mounting portion recessed in a radial direction between the teeth and formed integrally with the stator core, having an opening toward the air gap, and formed with inclined protrusions at both ends of the opening to narrow the width of the opening in the circumferential direction ; In addition, a motor including a magnet mounted on the magnet mounting unit may be provided.

The motor may be a three-phase motor for driving a drum of a washing machine.

Preferably, the magnet mounting portion is formed by punching the stator core.

The magnet mounting portion may include a circumferential surface formed radially apart from the opening, a radial surface extending from both ends of the circumferential surface toward the opening, and a space defined between the inclined protrusion and the radial ends of the inclined protrusion. can be The magnet mounting part is a space extending vertically, and it may be called a space in which a magnet is vertically inserted and mounted.

Preferably, the circumferential width of the opening is smaller than the circumferential width of the circumferential face.

The inclined protrusion may include: an inclined surface extending from a radial end of the radial surface in a direction in which a circumferential width of the opening is narrowed; And extending in the circumferential direction from the teeth may include a circumferential surface connected to the end of the inclined surface.

Preferably, the angle between the radial plane and the inclined plane is less than 180 degrees.

Preferably, the angle between the inclined surface and the circumferential surface is formed to be less than 90 degrees, and the radial width between the inclined surface and the circumferential surface becomes smaller in the circumferential direction.

A length of the inclined surface is preferably greater than a circumferential length of the inclined protrusion and a radial length of the inclined protrusion.

It is preferable that the circumferential length of the inclined protrusion and the radial length of the inclined protrusion are equal to each other.

The length in the circumferential direction and the length in the radial direction of the inclined protrusion are preferably 0.4 mm or more and 1.2 mm or less.

The magnet mounted to the magnet mounting unit may be formed smaller than the size of the magnet mounting unit to be vertically inserted into the magnet mounting unit. And it is preferable that the magnet mounted to the magnet mounting part is formed to be fitted to the magnet mounting part.

The magnet mounted to the magnet mounting portion may include a reference surface corresponding to the circumferential surface; a side surface corresponding to the radial surface; a chamfered surface corresponding to the inclined surface; And it is preferable to include an opposing surface forming the air gap. Preferably, the opposite surface is exposed to the outside of the air gap through the opening.

Preferably, the angle between the side surface of the magnet and the chamfer surface is greater than 90 degrees and smaller than the angle between the radial surface of the magnet mounting part and the inclined surface.

Preferably, the reference surface and the opposite surface of the magnet are formed in a curved surface. Accordingly, the magnet is formed to have a “C” shape, so that magnetic flux concentration in the radial direction can be effectively performed.

It is preferable that three teeth are formed per one tooth portion, and the magnet mounting portion is formed between the teeth and two teeth are formed per one tooth portion.

It is preferable that the circumferential width (pitch) of the teeth is smaller than the circumferential width (pitch) of the magnet mounting portion.

It is preferable that the circumferential widths of the three teeth are equal to each other, and the circumferential widths of the two magnet mounting portions are equal to each other.

Preferably, an insulator made of an insulating material is coupled to the upper and lower surfaces of the stator core, respectively, and the coil is wound after the insulator is coupled to surround the teeth.

The insulator may include a tooth cover part that covers the upper and lower surfaces of the magnet mounting part to support the upper and lower surfaces of the magnet vertically mounted on the magnet mounting part.

The motor according to this embodiment may exhibit performance equal to or higher than that of the conventional motor, and the structure may also be formed simply.

Features in the above-described embodiment may be implemented in combination as long as they are not contradictory or exclusive in other embodiments.

Through one embodiment of the present invention, it is possible to provide a motor with a simple structure, suppression of additional material cost increase, and suppression of increase in motor size.

Through one embodiment of the present invention, it is possible to provide a motor capable of mounting a permanent magnet to a stator stably while being simple to manufacture.

Through one embodiment of the present invention, it is possible to provide a motor capable of directly inserting the permanent magnet into the stator core, which is a magnetic body, and structurally and very effectively preventing the permanent magnet from being separated.

Through one embodiment of the present invention, it is possible to provide a motor that can effectively prevent the permanent magnets inserted into and mounted on the stator from being separated in the radial direction.

According to an embodiment of the present invention, it is possible to provide a motor capable of effectively preventing the permanent magnets vertically inserted into the stator from being separated in the vertical direction through the insulators respectively coupled to the upper and lower portions of the stator core.

Through one embodiment of the present invention, it is possible to provide a motor providing maximum performance by optimizing the ratio between the teeth of the stator core and the pitch of the magnet mounted between the teeth.

Through an embodiment of the present invention, when a plurality of teeth are formed in one tooth, a motor providing maximum performance by optimizing a ratio between the width of the tooth and the width of the passage branched from the tooth to the tooth is provided. can do.

According to an embodiment of the present invention, it is possible to provide a motor for driving a washing machine drum that is easy to manufacture and has excellent performance.

1 shows an example of a conventional motor,
2 shows an example of another conventional motor,
3 shows a part of a motor according to an embodiment of the present invention;
Figure 4 shows an enlarged view of a part of the motor shown in Figure 3,
5 shows an enlarged view by omitting the stator magnet in the motor shown in FIG. 3,
Figure 6 shows a change in the back electromotive force with respect to the inclined surface length (L1) of the inclined projection shown in Figure 5,
7 is a relationship between the length of the inclined surface (L1) of the inclined protrusion, the circumferential length (L2) of the inclined protrusion, and the radial length (L3) of the inclined protrusion shown in FIG. city,
8 shows an example of a motor according to an embodiment of the present invention,
9 shows the tooth pitch (β) and the magnet pitch (α) of the stator and the width (Wt) of the tooth and the width (Wm) of the passage in the motor according to an embodiment of the present invention;
10 shows the change of the back electromotive force and the permanent magnet material cost with respect to the change of the α/β ratio of FIG. 9;
11 shows a change in counter electromotive force, a change in torque ripple, and a change in efficiency with respect to the change in the α/β ratio of FIG. 9;
12 shows a change in efficiency with respect to a change in the Wt / Wm ratio of FIG. 9;
13 shows a change in efficiency with respect to a change in the Wt / Wm ratio of FIG. 9 and a change in the ratio of Wt / Wm with respect to a change in the tooth width (Wt),
14 shows a state of an embodiment for the passage portion and the magnet mounting portion for the magnetic flux saturation state and magnetic flux saturation prevention by the passage portion,
15 shows the appearance of another embodiment for the passage portion and the magnet mounting portion for the magnetic flux saturation state and magnetic flux saturation prevention by the passage portion,
16 shows the relationship between the passage part and the inclined surface of the magnet mounting part of another embodiment shown in FIG. 15;
17 shows the relationship between the number of slots in the stator, the end-turn length of the coil and the torque;
18 shows the relationship between the number of slots in the stator, the end-turn length of the coil and the efficiency;
19 shows the relationship between the number of slots in the stator, the iron loss, and the terminal voltage.

Hereinafter, a vernier motor according to an embodiment of the present invention will be described in detail with reference to the accompanying drawings.

The motor structure in the accompanying drawings shows a horizontal cross-section for convenience of description.

First, a basic structure of a vernier motor according to an embodiment of the present invention will be described with reference to FIG. 3 . In FIG. 3 , the motor 100 is shown for only one equal part among the motors divided into three parts in the circumferential direction for convenience.

The motor 100 may include a stator 200 and a rotor 110 . The stator is a configuration fixed to the object, and the rotor may be configured to rotate with respect to the fixed stator. As shown, the rotor 110 may be rotated radially outward with respect to the stator 200, and this motor may be referred to as an outer rotor type motor.

The stator 200 may include a core 210 , a tooth unit 220 , and a tooth 230 , and the core 210 , the tooth unit 220 , and the teeth 230 may be referred to as a stator core. That is, the stator core may include the core 210 , the teeth 220 and the teeth 230 . A slot 240 may be formed between the teeth 220 and the teeth 220 .

A plurality of teeth 230 may be provided in one tooth unit 220 . For example, two teeth may be formed in one tooth unit 220 . However, as will be described later, the number of teeth formed per one tooth may vary, and FIG. 3 shows an example in which three teeth 230 are formed in one tooth 220 .

The teeth 230 may be provided to form a gap G between the rotor and the rotor. That is, the configuration in which the gap G is formed by forming an end in the radial direction in the stator 200 may be referred to as the tooth 230 . The teeth 230 may be referred to as passages through which magnetic flux moves through the gap G between the rotor and the rotor. Therefore, it can be called a flux modulation pole (FMP).

The core 210 may be formed in an annular shape, and the center may be formed in a hollow shape. That is, as a whole, the core may be formed in a donut shape. The core 210 forms the center of the stator in the outer rotor type motor, and thus the teeth 220 may be formed to extend radially from the core 210 .

As shown in FIG. 3 , a plurality of tooth portions 220 may be provided to protrude outward in a radial direction from the core 210 in a circumferential direction. That is, the teeth 200 may protrude outward in the radial direction to form a stator of the outer rotor type motor. For convenience, a structure including all of the above-described core 210 , the teeth 220 , and the teeth 230 may be referred to as a stator core.

The stator core 205 and the plurality of teeth 220 may be integrally formed. That is, it may be formed to have a single body. Similarly, the teeth 230 formed on the teeth 220 may also be integrally formed with the teeth 220 . Of course, a plurality of pieces of the core 210 may be connected to each other along the circumferential direction to form the core 210 having one annular shape. This may be referred to as a split core 210 . That is, the plurality of core pieces may be connected to each other in the circumferential direction to form an annular stator core.

Of course, one or a plurality of teeth 220 may be integrally formed in each of the pieces of the stator core.

Such a stator core or stator core piece may be formed by punching a steel plate. That is, it is possible to form a stator core or a stator core piece by punching a steel sheet having a thin thickness. This punching process can be performed very precisely, so the dimensional error is very small. Therefore, separate machining is not required after punching.

Each steel sheet may be punched and then laminated to form a stator core. This stacking may determine the height of the stator core or the thickness of the stator core. Of course, this lamination can be performed after making the stator core into a strip shape. That is, the stator core of a single body may be formed by winding and stacking the band-shaped stator core in a spiral shape.

In any case, the overall shape, detailed structure and dimensions of the stator core 205 can be precisely formed through a punching process.

The stator 200 is provided with a coil 240 . Specifically, the coil 240 is formed in the form of winding the teeth 220 . A slot 240 is formed between the tooth 220 and the adjacent tooth 220 in the circumferential direction. The number of teeth 220 and slots 240 is the same. Accordingly, the number of coils 240 equal to the number of teeth or the number of slots is formed. The slot 240 may be a space in which the coil 240 is wound.

The coil 240 may be provided to form three phases, and U, V, and W phases may be alternately provided along the circumferential direction. Since one coil 240 per one tooth 220 forms each phase as it is wound, the number of the teeth 220 may be formed to have a multiple of three in the case of a three-phase motor.

According to this embodiment, the magnet 260 may be directly mounted on the stator core 205 . To this end, a magnet mounting part 250 may be formed in the stator core 205 .

The magnet mounting part 250 may be formed as a part of the stator core 205 . That is, when the stator core 205 is formed by punching, the magnet mounting portion 250 may be formed at the same time. In other words, the magnet mounting portion 250 may be formed on the stator core 205 itself, not on a material different from that of the stator core 205 . Accordingly, a separate material, a separate process, or a separate space for forming the magnet mounting part 250 is not required. That is, the magnet mounting part 250 may be formed as a part of the stator core 205 .

As shown in FIG. 3 , three teeth 230 may be formed in one tooth part 220 . It may extend from the radial end of the tooth portion 220 to the left and right in the circumferential direction to form two teeth 230 at both ends and one tooth 230 in the center. The teeth may be positioned to face the rotor.

The magnet mounting part 250 may be formed between the teeth 230 and the teeth 230 adjacent to one tooth part 220 . Accordingly, when three teeth 230 are formed in one tooth portion 220 , two magnet mounting portions 250 may be formed.

The magnet mounting part 250 may be formed by being depressed in the radial direction between the teeth 230 and the teeth 230 . Specifically, the magnet mounting part 250 may be formed in a form in which the space between the teeth 230 and the teeth 230 is removed. Accordingly, when the stator core 205 is punched, the magnet mounting part 250 may be formed at the same time. In other words, the magnet mounting part 250 may be formed as a part of the stator core 205 of a magnetic material.

The rotor 110 may include a rotor core 111 and a magnet 114 , and the magnet may be provided with an S-pole magnetization magnet 112 and an N-pole magnetization magnet 113 alternately. A plurality of magnets 114 may be provided along the circumferential direction of the rotor core 111 , and the magnetization directions are alternated.

Specifically, the magnet 114 may include a real magnet 112 and a virtual magnet 113 . The real magnet 112 is a magnet made of a magnetic material, and the virtual magnet 113 may mean a space between the real magnet 112 and the real magnet 112 or a non-magnetic material filled in the space.

As shown in FIG. 4 , the actual magnet 112 may be magnetized so that magnetic flux flows inward in the radial direction. In fact, the radially inner side of the magnet 112 may be magnetized with the N pole and the radially outer side with the S pole. These actual magnets 112 are arranged at predetermined intervals along the circumferential direction of the rotor. Accordingly, the magnetization direction of the virtual magnet 113 is opposite to that of the real magnet 112 .

The circumferential width of the real magnet 112 is preferably larger than the circumferential width of the virtual magnet 113 . Accordingly, it is possible to manufacture a high-efficiency motor using the magnetic flux generated from the actual magnet 112 .

As shown in FIG. 4 , the magnetization direction of the magnet 260 provided in the stator may be the same as the magnetization direction of the actual magnet 112 . Accordingly, an attractive force is generated between the magnet 112 of the rotor and the magnet 260 of the stator. That is, attractive forces pulling each other in the radial direction are generated.

Assuming that the magnet 112 of the rotor is firmly fixed to the rotor core 112 , the magnet 260 of the stator receives a radially detached force. Accordingly, a fixing structure for preventing the magnet 260 of the stator from being separated in the radial direction is required.

However, as in the prior invention, forming the fixed structure separately from the stator core causes many problems.

According to the present embodiment, the magnet mounting part 250 may be formed in the stator core 205 itself to mount and fix the magnet 260 .

The magnet mounting part 250 may be provided so that the magnet 260 is inserted after the stator core 205 is formed. That is, the magnet 260 is inserted in the vertical direction from the stator core 205, and the magnet 260 inserted radially outwardly may be formed so as not to be separated.

The magnet mounting part 250 is formed in a recessed shape between the teeth 230 and the teeth 230 . Accordingly, the magnet mounting part 250 has an opening 253 in a radial direction. The opening 253 may be said to be a magnet mounting part 250 opened toward the gap (G). Accordingly, there is a fear that the magnet 260 vertically inserted into the magnet mounting part 250 may be radially separated through the opening 253 .

In order to prevent the detachment of the magnet 260 , it is preferable that an inclined protrusion 255 is formed on the magnet mounting portion. Specifically, the inclined protrusion may be formed at both ends of the opening 253 so that the width of the opening 253 is narrowed in the circumferential direction. Accordingly, the inclined protrusion may be formed symmetrically with respect to the circumferential center of the opening.

In other words, two inclined protrusions 255 are formed on one magnet mounting part 250 . If the teeth arranged in the circumferential direction, the magnet mounting part, and the relationship between the teeth can be easily explained in a linear state, since the magnet mounting part is formed between the two teeth, the inclined protrusion in the left tooth 230 protrudes in the right direction and In the tooth 230, the inclined projection protrudes in the left direction. Accordingly, the width of the opening is narrowed by the protrusion length of the inclined protrusion. Therefore, the magnet 250 inserted into the magnet mounting part 250 and filling the magnet mounting part 250 may be prevented from being separated in the radial direction by the narrowed opening.

The magnet mounting part 250 has a circumferential surface 251 formed to be radially spaced apart from the opening 253, and a radial surface extending from both ends of the circumferential surface 251 toward the opening 253 ( 252). Accordingly, the magnet mounting part 250 may be defined as a space defined between the circumferential surface 251 , the radial surface 252 , and between the inclined protrusion 255 and the radial ends of the inclined protrusion 255 . That is, this space is a space having a cross section recessed between the teeth and the magnet 260 may be mounted in this space.

The circumferential surface 251 may be formed in a curved shape having a single radius of curvature. In addition, the end of the inclined protrusion 255 and the end of the inclined protrusion 255 may form a curved opening 253 having a single radius of curvature. Accordingly, the magnet mounting part 250 has a “C” shape, and thus the magnet 260 mounted on the magnet mounting part 250 may also have a “C” shape. Therefore, it is preferable that the circumferential width of the opening 253 is smaller than the circumferential width of the circumferential surface 251 so that the magnet mounted on the magnet mounting part 250 does not disengage in the radial direction.

As described above, the magnet mounting part 250 and the inclined protrusion 255 thereof may be a part of the stator core 205 . The inclined protrusion 250 is a protrusion protruding from the tooth 230 in the circumferential direction, and may be said to be formed during punching.

Punching is a process of forming a desired shape by pressing a steel sheet. Therefore, a structure having a thin thickness may be damaged during punching or easily damaged after punching. Accordingly, the protrusion protruding to narrow the circumferential width of the opening 253 is preferably a triangular protrusion. That is, it is preferable that the protrusion is formed in a shape in which the width becomes narrower in the protrusion direction. Due to this shape, a protrusion of a desired shape can be formed during punching, and damage to the protrusion can be effectively prevented.

Specifically, the protrusion 255 may include a circumferential surface 257 and an inclined surface 256 . Due to the inclined surface 256 , this protrusion may be referred to as an inclined protrusion 255 . The circumferential surface 257 is a surface extending in the circumferential direction from the radial end of the tooth, and the inclined surface 256 extends toward the end of the circumferential surface 257 from the side surface of the tooth or the radial end of the magnet mounting part. It can be said that the side of Accordingly, it is preferable that the angle Y between the radial surface (the side surface of the tooth) of the magnet mounting portion and the inclined surface is less than 180 degrees.

The circumferential surface 257 and the inclined surface 256 intersect each other, and this intersection point may be referred to as an end of the inclined protrusion. Accordingly, the angle Z between the circumferential surface 257 and the inclined surface 256 is preferably less than 90 degrees. Therefore, the inclined protrusion 255 has a right-angled triangular shape protruding in the circumferential direction due to the inclined surface 256 and the circumferential surface 257, and the radial width becomes narrower in the protruding or circumferential direction. Since the thickness at the starting point of protrusion in the inclined protrusion 255 is the largest, punching is easy and damage can be minimized during punching.

As described above, the magnet 260 mounted on the magnet mounting unit 250 is inserted into and fixed to the magnet mounting unit 250 . Therefore, the magnet 260 is formed to be fitted to the magnet mounting part 250 , and preferably smaller than the size of the magnet mounting part 250 .

Therefore, the magnet 260 corresponds to the reference surface 261 corresponding to the circumferential surface 251 of the magnet mounting portion, the side surface 262 corresponding to the radial surface 252 of the magnet mounting portion, and the inclined surface 256. It includes a chamfered surface 263 that is formed and an opposing surface 264 forming the air gap (G). A radius of curvature of the opposite surface may be formed to coincide with a radius of curvature of the stator core 205 . Similarly, the reference surface 261 of the magnet may be formed as a curved surface having a single radius of curvature.

The chamfered surface 263 of the magnet 260 may be a portion obtained by chamfering a corner portion. Therefore, the angle X between the side surface 262 of the magnet 260 and the chamfer surface 263 is important. Preferably, the angle (X) is smaller than the angle (Y). This is because, when the angle X is smaller than the angle Y, the tolerance g between the magnet 260 and the magnet mounting part 250 can be minimized. That is, the magnet 260 and the magnet mounting unit 250 may be formed with a certain tolerance and the magnet 260 may be mounted to the magnet mounting unit 250 at the same time. And, since it is possible to manage the tolerance (g), it is possible to effectively prevent the inserted magnet 260 from shaking in the magnet mounting unit 250 .

On the other hand, the inclined protrusion 255 in the magnet mounting part 250 is configured to prevent the detachment of the magnet 260 , thereby substantially reducing the volume of the magnet mounting part 250 . This means that the volume of the magnet 260 mounted on the magnet mounting part 250 is reduced. That is, it means that the volume of the magnet 260 is reduced by the volume corresponding to the chamfered surface 263 of the magnet. Also, magnetic flux leakage may occur in the circumferential direction due to the inclined protrusion 255 .

Therefore, when there is no such inclined protrusion 255, the electromagnetic performance can be said to be the maximum. In the absence of the inclined protrusion 255 , when the counter electromotive force representing the performance of the motor is 100%, the size of the inclined protrusion 255 is limited. If the size of the inclined protrusion 255 is increased, the magnet 260 may be more firmly prevented from being separated, but the performance of the motor is deteriorated.

On the other hand, there is a limit in reducing the size of the inclined protrusion 255 . This is because the inclined projection 255 must be integrally formed with the stator core 205 by punching.

An optimum value for the size of the inclined protrusion 255 will be described in detail with reference to FIGS. 5 to 7 .

5, the inclined projection 255 is stably punched and the length L1 of the inclined surface 256 is the radial length L2 of the inclined projection 255 and the slope so that damage is prevented after stripping. It is preferably greater than the circumferential length L3 of the protrusion 255 .

Specifically, the radial length L2 of the inclined protrusion 255 and the circumferential length L3 of the inclined protrusion 255 may be formed to be the same. Accordingly, the inclined protrusion 255 may have an isosceles triangular shape in which the length of the inclined surface is as long as possible.

Here, it can be seen that the length L1 of the inclined surface 256 is determined by the radial length L2 of the inclined protrusion 255 and the circumferential length L3 of the inclined protrusion 255 . It can be seen that L1, L2, and L3 are all 0 when there is no inclined protrusion 255 .

As shown in FIG. 6 , as the inclined surface length L1 of the inclined protrusion increases, the size of the inclined protrusion 255 increases, and thus it can be seen that the counter electromotive force decreases. A decrease in such counter electromotive force means a decrease in the performance of the motor.

In particular, there is a limit in reducing the circumferential length L3 and the radial length L2 of the inclined protrusion 255 . That is, a minimum length must be ensured to facilitate punching and prevent damage to the inclined protrusion.

Therefore, it is not preferable to make the length of L2 or L3 smaller than 0.4 mm as shown in FIG. 7 . Of course, in the case of less than 0.4 mm, the back electromotive force may approach 100%, which is the standard, but various problems such as difficulty in punching, damage to the inclined protrusion 255 after punching, and separation of the magnet 260 may occur. Accordingly, the length of L2 or L3 is preferably 0.4 mm or more. Through this, even if the stress is concentrated in the radial length portion of the inclined projection, the inclined projection is not damaged.

On the other hand, as the length of L2 or L3 increases, the size of the inclined protrusion 255 increases and the counter electromotive force decreases. As described above, since the length L1 of the inclined surface is determined by L2 and L3, it can be seen that the back electromotive force decreases as L1 increases, as shown in FIGS. 6 and 7 .

Therefore, in order to minimize the decrease in electromagnetic performance, it is necessary to limit the size of the inclined protrusion to have 95% of the reference electromotive force. That is, it is preferable to limit the size of the inclined protrusion to 1.2 mm or less based on L2 to L3.

Consequently, it will be preferable to determine L2 or L3 of the inclined protrusion between 0.4 mm and 1.2 mm. Also, the range of L1 may be determined through the ranges of L2 and L3. When L2 and L3 are the same and the angle between L2 and L3 is a right angle, L1 may be determined to be larger than L2 and L3 using a trigonometric function. In FIG. 7, L1 is shown as a value when L2 and L3 have the same length and are perpendicular to each other.

The above-described magnet mounting part 250 or the inclined protrusion 255 may be formed for radial deviation of the magnet 260 .

Since the magnet 260 is vertically inserted into the magnet mounting part 250 , there may be a risk that the inserted magnet 260 may be vertically separated by impact. In order to prevent the vertical separation of the magnet 260 , an insulator 270 may be provided in an embodiment of the present invention.

As shown in FIG. 8 , the insulator 270 covers the upper and lower portions of the stator core 205 and insulates between the stator core 205 and the coil 240 . Accordingly, the configuration of the insulator 270 may be a general configuration in a motor driving the drum of a washing machine.

The insulator 270 may include an upper insulator that covers the upper portion of the stator core 205 and a lower insulator that covers a lower portion of the stator core 205 , and they may be coupled to each other to surround the stator core 205 .

Specifically, the insulator 270 may include a core cover 271 covering the core and a tooth cover 273 covering the teeth. The coil 240 is wound while surrounding the tooth cover 273 .

In this embodiment, the tooth cover 273 may include a tooth cover 274 that extends further in the radial direction to cover the teeth. The tooth cover 274 may be formed to cover not only the teeth but also the magnet mounting part 260 . A coupling portion 272 for coupling the stator to the tub of the washing machine may be formed inside the core cover 271 in the radial direction. All of these components may be integrally formed by injection.

Accordingly, the upper insulator covers the upper portion of the magnet mounting portion and the lower insulator covers the lower portion of the magnet mounting portion. For example, after coupling the lower insulator and the stator core, the magnet may be inserted into the magnet mounting portion. The upper insulator may then be coupled to the stator core and the lower insulator. By this structure and assembly sequence, the magnet can be prevented from being vertically separated from the magnet mounting part.

Reinforcing ribs 275 may be formed on the tooth cover 274 of the insulator 270 according to the present embodiment. That is, the reinforcing ribs 275 extending in the circumferential direction from the radial end portion of the tooth cover 274 may be formed. Accordingly, even when force is applied to the tooth cover 274 by the magnet in the vertical direction, the tooth cover 274 can stably support the magnet by the reinforcing rib 275 .

Through the above-described embodiments, it is possible to very easily mount the magnet by integrally forming the magnet mounting portion in a shape recessed in the stator core. In addition, it is possible to prevent the magnet from being separated in the radial direction through the inclined protrusion of the magnet mounting portion. In addition, by changing the structure of the insulator, it is possible to effectively prevent the magnet from being vertically separated from the magnet mounting portion.

In addition, it is possible to provide a very efficient and robust motor through the shape and size range of the inclined protrusion.

Hereinafter, an embodiment of the structure of the stator core capable of increasing the output density of the motor by increasing the counter electromotive force will be described in detail.

First, it was found that the counter electromotive force changes according to a change in the ratio (α/β) of the circumferential length of the teeth (FMP pitch, β) to the circumferential length of the stator magnet (stator pitch, α).

Based on the case where the α/β ratio is 1, the changes in counter electromotive force, torque ripple, and efficiency according to the increase and decrease of the α/β ratio are shown in FIGS. 10 and 11 .

As a result of varying the α/β ratio around 1, it was found that the back EMF and efficiency basically increased as the α/β ratio became larger than 1. And, it was found that the torque ripple performance also showed an increasing trend. That is, it was found that the stator pitch is preferably larger than the FMP pitch.

It can be seen that the α/β ratio is 1.2 or more so that the efficiency performance is 105% or more based on the α/β ratio being 100% at 1. It can be seen that the torque ripple performance is still further improved in the process of increasing this ratio.

When the ratio further increases, the efficiency tends to further increase, and it can be seen that the torque ripple performance is improved and then rapidly decreased. That is, when the α/β ratio exceeds 2.1, it can be seen that the torque ripple performance is lower than the torque ripple performance when the α/β ratio is 1.

Considering the relationship between the α/β ratio, the back EMF performance, the efficiency, and the torque ripple, it was found that the optimal α/β ratio was 1.2 to 2.1.

In particular, an example in which three teeth 230 are formed at the radial end of one tooth portion 220 is shown in the stator core 205 shown in FIG. 9 . That is, a stator core having three teeth per one tooth and two stator magnets is shown.

Therefore, in the stator core 205 having this structure, the α/β ratio may be preferably determined between 1.2 and 2.1.

In addition, in order to achieve symmetry, β of the three teeth is preferably equal to each other, and α of the two stator magnets is preferably equal to each other. And, it will be preferable that the teeth and the magnet mounting portion on both sides are formed symmetrically with respect to the teeth positioned in the middle.

Characteristics of the magnet mounting part 250 in this embodiment, the stator core, and the rotor will be the same as in the above embodiment.

Meanwhile, as shown in FIG. 9 , since a plurality of teeth 230 are formed in one tooth 220 , the width of the magnetic flux passage toward the tooth 230 is greater than the width of the magnetic flux passage in the tooth 220 . can only become smaller. This is because one tooth part 220 is branched into a plurality of teeth 230 . Such a branching path may be referred to as a passage portion 225 .

The passage portion 225 is a part of the stator core 205 , and may be a portion extending from the tooth portion 220 in both circumferential directions to be connected to both teeth.

In particular, as in the present embodiment, when three teeth 230 are formed on one tooth portion 220 , the relationship between the width Wt of the tooth portion 220 and the width Wm of the passage portion is the motor can have a significant impact on the efficiency of

12 and 13 show the relationship between the Wt/Wm ratio and the efficiency of the motor. And, since Wt must be greater than Wm (assuming that the main passage is larger than the branch passage), it would be preferable to first determine Wm and then vary Wt.

As shown, when the Wt/Wm ratio is changed, it can be seen that the efficiency is maintained at approximately 85% within a certain range. That is, within the range of 2.63 to 3.38 of the Wt/Wm ratio, the efficiency is maintained at approximately 85% and does not change. However, it can be grasped that the efficiency is rapidly lowered before and after this range.

Therefore, it is preferable that the Wt/Wm ratio is determined within a section in which the efficiency satisfies 85%. In order to satisfy such a Wt/Wm ratio, Wt may be determined within a range of 21 mm to 27 mm.

Characteristics of the magnet mounting part 250 in this embodiment, the stator core, and the rotor will be the same as in the above embodiment.

Therefore, Wt, which is the passage width in this embodiment, may be affected by the magnet mounting portion.

For example, when the passage portion is formed to be inclined, a gap between the passage portion and the magnet mounting portion may be narrowed. In the left figure of FIG. 14 , it can be seen that when the passage is extended in an oblique shape, the width between the magnet mounting portion and the edge portion is narrowed, and magnetic flux saturation occurs in this portion.

In order to prevent this, as shown in the right figure of FIG. 14 , it is preferable that the passage portion extends in the circumferential direction. In particular, it is preferable to connect the passage portion with the teeth after extending further in the circumferential direction than the magnet mounting portion. Accordingly, it can be seen that the magnetic flux saturation at the edge portion of the magnet mounting portion is significantly reduced.

On the other hand, extending the passage in the circumferential direction can be said to increase the length of the magnetic flux path. That is, it can be said that the magnetic flux moving in the radial direction detours in the circumferential direction.

Accordingly, assuming that magnetic flux saturation is prevented, it is preferable that the passage portion extends in an oblique direction. That is, it is preferable that the passage portion between the teeth extends in an oblique shape. That is, the angle between the tooth portion and the passage portion is preferably greater than approximately 90 degrees. The extension of the passage portion in the circumferential direction may be less than approximately 90 degrees.

However, in this case, magnetic flux saturation occurs at the edge of the magnet mounting part as shown in the left figure of FIGS. 14 and 15 . It can be seen that this magnetic flux saturation is closely related to the decrease of Wm.

Therefore, it is preferable to form the edge portion of the magnet mounting portion that determines the width of the passage between the passage portion and the passage portion without changing the shape of the passage portion as an inclined surface. An example of this may be referred to as the right figure of FIG. 15 .

That is, by forming the inclined surface 258 of the magnet mounting portion substantially parallel to the passage portion, the width of the passage portion may be increased. Of course, a chamfered surface may be formed on the stator magnet 260 to correspond to the inclined surface 258 . This chamfered surface is different from the chamfered surface for preventing magnet separation in the above-described embodiment, and it is preferable that the width is also larger.

The magnet mounting portion may include a circumferential surface 251 and radial surfaces 252 and 252a on both sides. An inclined surface 258 may be formed at an edge portion between the radial surface 252a and the circumferential surface 251 at a position further spaced apart from the circumferential center of the tooth portion 220 . Due to this inclined surface, the length of the radial surface 252a is smaller than the length of the other radial surface 252 .

Preferably, the angle θ between the radial surface 252a and the inclined surface 258 is approximately 59 degrees. In addition, the inclined surface 258 is preferably formed in parallel with the passage.

Meanwhile, the motor described in the above-described embodiments may be a motor for driving the drum of the washing machine. As an example, it may be a motor in which the rotor rotates radially outward relative to the stator.

The stator, for example, by the coupling part 272 of the insulator shown in FIG. 8, may be fixed to the rear wall of the tub. A shaft connected to the center of the drum through the rear wall of the tub may be connected to the center of the rotor through the center of the stator. Accordingly, as the rotor rotates with respect to the stator fixed to the tub, the drum may rotate.

In the case of a drum washing machine (front loader), there is a limit in increasing the front and rear length of the motor (that is, the height of the motor) due to the limitation of the front and rear size of the cabinet. Similarly, in the case of a top loader, there is a limit to increasing the height of the motor due to the limit of the upper and lower sizes of the cabinet.

The motor for driving the drum of the washing machine is a three-phase motor, and recently, it is being controlled very precisely using an inverter.

Since the motor driving the drum of the washing machine needs to perform various operations such as washing, rinsing and dehydration, it will have to satisfy standard torque performance and efficiency.

In particular, as described above, an increase in the height of the motor is very limited because it causes an increase in the cabinet size. What determines the height of the motor is the end-turn length of the coil.

The coil is wound on the teeth of the stator, and as the number of turns increases or the wire diameter of the coil becomes thicker, the end-turn length inevitably increases. Since the end-turn refers to a coil portion protruding upward and downward of the tooth, the sum of the thickness of the stator core and the length of the upper and lower end-turns can be referred to as the height of the stator.

On the premise that the number of turns of the stator, that is, the number of turns of the entire coil is constant, as the number of slots of the stator core increases, the length of the end-turn inevitably decreases. This is because, when the number of slots is large, the number of turns per slot is reduced, so the length of the end-turn is inevitably reduced.

It is possible to determine the optimal number of slots through the relationship between the number of slots and the requirements of the three-phase motor for driving the motor of the washing machine.

Since it is a three-phase motor, the number of slots should be selected as a multiple of 3 in order for the three-phase coil to be wound. Basically, the number of slots and the number of teeth should be 6 or more.

17 shows the relationship between the number of slots and torque performance. When the number of slots is 6, the height of the end-turn becomes larger than the required condition, which causes an increase in the size of the motor. And, the torque performance also did not satisfy the requirements.

However, it was found that when the number of slots was 9, both the end-turn condition and the torque condition were satisfied. Of course, as the number of slots increases, the end-turn length tends to become smaller.

Based on the torque condition, it was found that the number of slots was satisfied at 9, 12, 15, 18, and 21. As the number of slots increased from 9 to 18, the torque performance gradually improved and then decreased sharply at 21, but the torque condition was also satisfied at 21. However, it was found that the torque performance was superior to the number of slots 21 in the number of slots 9.

18 shows the correlation between the number of slots and the efficiency. It was found that the efficiency gradually decreased as the number of slots increased. It can be seen that the efficiency condition is satisfied even with approximately the number of slots 21, but the number of slots is satisfied at 9, 12, 15, and 18 when the efficiency condition is strengthened to 80% or more. Accordingly, the number of slots is preferably 9, 12, 15, and 21 through the efficiency condition and the end-turn length condition.

19 shows the correlation between the iron loss, the terminal voltage, and the number of slots. It can be seen that the terminal voltage and iron loss tend to increase as the number of slots increases. In particular, it can be seen that the iron loss and terminal voltage have a tendency to rapidly increase in the section where the number of slots increases from 18 to 21. Therefore, it can be seen that in the case of the number of slots 9, 12, 15 and 18, the iron loss and terminal voltage conditions are all satisfied.

As a result, it was found that in the three-phase motor for driving the drum of a washing machine, the number of slots of the stator was determined to be any one of 9, 12, 15 and 18 is optimal. That is, it was found that the number of slots within this range is optimal in consideration of the end-turn condition, torque condition, efficiency condition, iron loss condition, and terminal voltage condition, and the number of slots outside this range significantly deviates from each condition.

As shown in Fig. 1, in general, the number of slots in the stator in the three-phase motor for driving the drum of a washing machine is greater than 24. Therefore, since there are many places where a coil should be formed, it is not easy to form a coil. And, the winding machine is inevitably complicated due to an increase in the number of coils.

However, in the case of the three-phase motor for driving the drum of a washing machine according to the present embodiment, any one of 9, 12, 15, and 18 having a number of slots smaller than 24 may be selected and applied. Accordingly, the manufacture of the stator becomes very easy. In addition, since the same type of rotor can be used, there is no need to specifically re-manufacture the rotor.

Due to the reduction in the number of slots, the structure of the above-described insulator is also simplified.

In addition, in the case of the three-phase motor for driving the drum of a washing machine according to the present embodiment, it is possible to provide a more efficient motor by mounting a magnet to the stator as well as electromagnetic force by a coil in the stator of the same size as the existing one. In particular, since the size of the tooth portion is larger than the size of the existing tooth portion due to the reduction in the number of slots, the magnet mounting portion may be integrally formed in a portion of the tooth portion to facilitate mounting of the magnet.

In the case of a conventional three-phase motor for a washing machine, since the number of slots is large, the size of the teeth part and the teeth which are the ends of the teeth part are relatively small. Therefore, there is no space for mounting the magnet by being depressed in the teeth, and there is a problem in that the size of the stator increases when the magnet is mounted through the injection structure separately from the stator core.

Simply assuming that the size (diameter of the stator core) of the stator core shown in FIG. 1 and the stator core shown in FIG. 3 are the same, the difference in the size of the stator core according to this embodiment can be intuitively recognized, It can be seen that this allows the magnet to be mounted by recessing a portion of the radially distal portion of the stator core.

In addition, in this embodiment, it can be seen that the radial width of the teeth is significantly larger than the radial width of the teeth in the conventional washing machine motor. Accordingly, it can be seen that the magnet can be supported by effectively covering the magnet mounting portion through the insulator.

100: motor 110: rotor
111: rotor core 112: rotor magnet
200: stator 205: stator core
210: core 220: tooth part
230: teeth 240: coil
250: magnet mounting part 260: stator magnet

Claims (20)

a rotor provided with a plurality of magnets along the circumferential direction;
It includes a core, a tooth portion extending from the core to face the rotor, and two or more teeth (FMP, flux modulation pole) formed in the tooth portion and having an air gap with the rotor, formed by punching a magnetic steel plate being a stator core; and
In the motor comprising a coil wound in the slot between the teeth and the teeth,
A stator magnet is provided between the teeth and the teeth,
The motor, characterized in that the ratio (α/β) of the circumferential length (stator pitch, α) of the stator magnet to the circumferential length (FMP pitch, β) of the teeth is 1.2 to 2.1. The method of claim 1,
The stator core is recessed in a radial direction between the teeth and the motor characterized in that the magnet mounting portion integrally formed with the stator core is formed. 3. The method of claim 2,
The magnet mounting portion, motor characterized in that formed integrally with the stator core by punching the stator core. 4. The method of claim 3,
The motor according to claim 1, wherein, for each of the teeth, three teeth are formed and two stator magnets are provided. 5. The method of claim 4,
β of the three teeth is equal to each other, and α of the two stator magnets is equal to each other. 6. The method of claim 5,
The motor is
As the ratio (α/β) increases from 1.0, the counter electromotive force and the efficiency tend to increase, and the torque ripple tends to increase after decreasing. 7. The method of claim 6,
The motor is
In the range where the ratio (α/β) is 1.2 to 2.1, the efficiency is 105% or more and the torque ripple is 95% or less, compared to 100% efficiency and 100% torque ripple in the case where the ratio (α/β) is 1.0 motor characterized. 5. The method of claim 4,
wherein the stator core includes a passage portion extending from the tooth portion in both circumferential directions and connected to the tooth portion. 9. The method of claim 8,
The motor, characterized in that the width (Wt) in the longitudinal direction of the teeth is greater than the width (Wm) in the longitudinal direction of the passage. 10. The method of claim 9,
A ratio (Wt/Wm) of the width (Wt) to the width (Wm) is 2.63 to 3.38. 11. The method of claim 10,
The motor efficiency is characterized in that the ratio (Wt/Wm) is 85% or more within the range of 2.63 to 3.38. 9. The method of claim 8,
The motor, characterized in that the passage portion is connected to the teeth after extending in the circumferential direction past the magnet mounting portion. 9. The method of claim 8,
The motor is characterized in that the passage portion is connected to the teeth by extending in the form of an oblique line having an angle greater than 90 degrees with the teeth portion. 14. The method of claim 13,
In order to increase the width between the circumferential end of the magnet mounting portion and the passage, an edge portion of the magnet mounting portion is formed to have an inclined surface. 15. The method of claim 14,
The inclined surface is a motor, characterized in that formed to be parallel to the passage portion. 15. The method of claim 14,
An edge of the stator magnet mounted on the magnet mounting unit has a chamfered surface corresponding to the inclined surface. 17. The method of claim 16,
The magnet mounting portion,
a circumferential surface and a radial surface extending radially from both ends of the circumferential surface, respectively;
The motor, characterized in that the inclined surface is formed only between the circumferential surface and any one of the radial surfaces. 18. The method of claim 17,
The inclined surface is a motor, characterized in that formed only at the edge portion further spaced apart from the tooth portion in the circumferential direction of both ends of the circumferential surface. 19. The method of claim 18,
The motor, characterized in that the angle between the radial surface and the inclined surface is 59 degrees. a rotor provided with a plurality of magnets along the circumferential direction;
It includes a core, a tooth portion extending from the core to face the rotor, and two or more teeth (FMP, flux modulation pole) formed in the tooth portion and having an air gap with the rotor, formed by punching a magnetic steel plate being a stator core; and
In the motor comprising a coil wound in the slot between the teeth and the teeth,
A stator magnet is provided between the teeth and the teeth,
The stator core includes a passage portion extending from the tooth portion to both sides in the circumferential direction and connected to the tooth,
The width (Wt) with respect to the longitudinal direction of the teeth is greater than the width (Wm) with respect to the longitudinal direction of the passage,
A ratio (Wt/Wm) of the width (Wt) to the width (Wm) is 2.63 to 3.38.

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