JP7359561B2 - Flux switching motor, fan motor and battery-powered vacuum cleaner using the same - Google Patents

Description

The present disclosure relates to a flux switching motor, a fan motor using the same, and a battery-powered vacuum cleaner.

BACKGROUND ART Conventionally, a flux switching motor as disclosed in Patent Document 1, for example, has been disclosed as an electric motor that is a type of rotating electric machine.

The flux switching motor of Patent Document 1 includes a rotating shaft, a rotor fixed to the rotating shaft and rotatable around the rotating shaft, and a stator disposed facing the rotor so as to surround the outer periphery of the rotor. It is equipped with. The stator includes a plurality of stator teeth in which field slots and armature slots are alternately arranged in the circumferential direction around the rotation axis, and a pair of stator teeth each sandwiched between a pair of armature slots adjacent in the circumferential direction. a plurality of armature windings wound around stator teeth; and a plurality of field windings each wound around a pair of stator teeth sandwiched between a pair of circumferentially adjacent field slots. , a plurality of field magnets, each of which is accommodated in each field slot and arranged such that magnetic pole faces of the same polarity face each other in the circumferential direction.

In Patent Document 1, each stator tooth is configured such that a radially inner tip portion faces the tip portion of each rotor tooth in the rotor via an air gap. Each magnet is housed in each field slot so that its radially inner end is flush with the tip of each stator tooth (see FIGS. 1 to 4 of Patent Document 1).

Further, FIG. 1 of Patent Document 2 also discloses a flux switching motor having a configuration similar to the flux switching motor of Patent Document 1.

Japanese Patent Application Publication No. 2016-032384 Japanese Patent Application Publication No. 2013-201869

Incidentally, in recent years, smaller and lighter battery-powered vacuum cleaners (especially cordless stick vacuum cleaners) have become popular in the market. Stick vacuum cleaners have been put into practical use as highly convenient vacuum cleaners because they do not require a power cord and are lightweight. On the other hand, the suction power of a typical stick vacuum cleaner is inferior to that of a vacuum cleaner with a power cord, making it difficult to use it as a main vacuum cleaner. For this reason, cordless stick vacuum cleaners are required to have high suction power equivalent to that of a vacuum cleaner with a power cord, without sacrificing the characteristics of being small and lightweight. Specifically, it is required that the fan motor installed in a stick vacuum cleaner has a high output. In order to meet this requirement, it is conceivable to mount a fan motor equipped with a flux switching motor capable of rotating at an extremely high speed, such as those disclosed in Patent Documents 1 and 2, in a stick vacuum cleaner.

In the flux switching motors of Patent Documents 1 and 2, in order to improve the output, it is desirable to make the air gap as small as possible. However, extremely high manufacturing precision is required to further reduce the air gap. Therefore, it is practically difficult to make the air gap extremely small. As a result, on the radially inner peripheral side of the stator, near the end of the stator teeth in the axial direction of the rotating shaft (hereinafter referred to as the ``axial direction''), the magnetic flux generated from the magnet (hereinafter referred to as ``magnet magnetic flux'') Some of it crosses the air gap and becomes difficult to flow to the rotor teeth. This causes a leakage magnetic flux that returns to the end of the stator teeth, and also causes a leakage flux that returns from the end of the stator teeth to the axial end of the magnet. As a result, the output becomes insufficient and the size of the motor becomes large as a result.

Further, a flux switching motor is generally a structure made of iron, and a relatively large amount of iron is used among the elements constituting the motor. For this reason, it is not easy to reduce the amount of iron in the components of a flux switching motor to make it extremely lightweight.

As described above, in the flux switching motors of Patent Documents 1 and 2, it is not easy to achieve both high output by increasing torque and miniaturization and ultra-lightweight.

The present disclosure has been made in view of the above, and the main purpose thereof is to obtain a flux switching motor that achieves both high output, miniaturization, and ultra-light weight.

In order to achieve the above object, a first embodiment of the present disclosure relates to a flux switching motor, and the flux switching motor includes a rotating shaft and a plurality of rotor teeth that are rotatable around the rotating shaft. A rotor having a rotor. The flux switching motor also includes a plurality of stator teeth, each of which faces each of the plurality of rotor teeth via an air gap, a plurality of armature slots and a plurality of field slots arranged alternately. The stator includes a plurality of magnets disposed in each of a plurality of field slots, and a plurality of armature coils each wound around each armature slot so as to straddle each magnet. The length of the stator in the axial direction at the rotating shaft is shorter than the length in the axial direction of the magnet, and the length of the rotor in the axial direction is shorter than the length in the axial direction of the stator. The top end of the rotor is located below the top end of the stator, and the top end of the stator is located below the top end of each magnet. The lower end of the stator is located above the lower end of the stator, and the lower end of the stator is located above the lower end of each magnet.

In this first form, the leakage flux in the axial direction is reduced near the boundary between the stator and the magnet due to the magnet overhanging the stator. That is, the loop path of leakage magnetic flux from the axial end face of the stator to the axial end face of the magnet is blocked, and the magnetic flux flowing to the stator increases. As a result, the magnetic flux that contributes to higher output due to increased torque increases. Furthermore, the overhang of the stator with respect to the rotor increases the gap magnetic flux density of the air gap, increasing the magnetic flux flowing to the rotor, and increasing the magnetic flux that contributes to higher output due to increased torque. Furthermore, since the axial lengths of both the rotor and the stator are shorter than the axial lengths of the magnets, the overall size of the motor can be reduced, resulting in a more compact flux switching motor. Furthermore, by making the rotor and stator relatively smaller in size, it is possible to reduce the weight of the materials that make up the rotor and stator (e.g. iron material as a magnetic material), making it possible to Lighter. Therefore, in the first embodiment, it is possible to obtain a flux switching motor that achieves both high output, miniaturization, and ultra-light weight.

In the second form, in the first form, a plurality of magnets are each housed in each field slot and are arranged so that the magnetic pole faces of the same polarity face each other in the circumferential direction, and each magnet is attached to the rotation axis. In contrast, the first end is arranged on the side closer to the rotor in the radial direction, and the second end is arranged on the side farther from the rotor, and the circumferential width at the second end is longer than the circumferential width at the first end. It is characterized by being formed as follows.

In the second form, since the circumferential width at the second end is longer than the circumferential width at the first end, the magnet when the flux switching motor is viewed planarly in the axial direction of the rotating shaft The outer shape is approximately trapezoidal, tapering toward the side where the rotor is located. As a result, the surface area of the circumferentially facing side portion of the magnet becomes relatively large, and the contact area between the stator and the magnet increases. As a result, the magnetic flux generated from the magnet easily flows to the stator. Therefore, the magnetic flux of the magnet that excites the rotor increases, and the output can be further increased.

In the third form, in the second form, the radial position of the first end of the magnet about the rotation center of the rotating shaft is radially more than the radial position of the end of the stator teeth. It is arranged so as to be located on the outside , and is characterized in that a fillet is provided at the outer corner of the first end.

In this third form, the amount of magnet exposure to fringing magnetic flux generated between stator teeth and rotor teeth and leakage magnetic flux from stator teeth is reduced, resulting in irreversible demagnetization, that is, a decrease in magnetic force. Since this can suppress the output of the motor, it is possible to stabilize the output of the motor and suppress a deterioration in the performance of the motor. Moreover, since the eddy current generated when the fringing magnetic flux passes through the magnet can be similarly reduced, it is also possible to realize higher efficiency of the motor.

In a fourth embodiment, in any one of the first to third embodiments, the magnet is an anisotropic Sm-Fe-N bonded magnet configured to contain a resin content of 40% or more in volume %. It is characterized by becoming.

In this fourth form, in an anisotropic Sm-Fe-N bonded magnet configured to contain a resin content of 40% or more in volume%, while the resin content is relatively large, the iron The content of is relatively small. For this reason, the loss of eddy currents generated in the magnet due to the magnet containing iron is reduced, so efficiency can be increased, and the amount of iron, copper, and magnet can be reduced to account for the increased efficiency. As a result, the weight can be reduced by the amount of material used. Further, the specific gravity (4.5 g/cm ³ ) of the anisotropic Sm--Fe--N bond magnet is smaller than, for example, the specific gravity (6.5 g/cm ³ ) of the Nd--Fe--B bond magnet. Therefore, by applying the above-mentioned anisotropic Sm-Fe-N bonded magnet, compared to, for example, a Nd-Fe-B bonded magnet, it is possible to obtain the above-mentioned magnetic flux of the desired strength while reducing the weight of the magnet. This makes it possible to suppress the increase. Therefore, by applying the anisotropic Sm--Fe--N bonded magnet to a flux switching motor, the weight of the motor can be further reduced .

In a fifth form, in any one of the first to fourth forms, an even number of rotor teeth are provided, and the difference between the number of armature slots and the number of rotor teeth is an even number. It is characterized by

In this fifth embodiment, eccentric rotation can be prevented by making the number of rotor teeth an even number and making the difference between the number of armature slots and the rotor teeth an even number. As a result, noise and vibration caused by the motor can be suppressed.

A sixth embodiment is characterized in that it is a fan motor equipped with the flux switching motor of any one of the first to fifth embodiments.

In this sixth embodiment, it is possible to obtain a fan motor that is small and lightweight and can be applied to a battery-powered vacuum cleaner that has high suction power .

A seventh embodiment is characterized in that it is a battery-powered vacuum cleaner equipped with the fan motor of the sixth embodiment.

In this seventh embodiment, it is possible to obtain a battery-powered vacuum cleaner that is small, lightweight, and has high suction power.

As described above, according to the present disclosure, it is possible to obtain a flux switching motor that achieves both high output, size reduction, and ultra-light weight reduction.

FIG. 1 is an overall perspective view showing a fan motor according to an embodiment. FIG. 2 is an exploded perspective view showing each structure of the fan motor. FIG. 3 is an overall perspective view showing the flux switching motor. FIG. 4 is a perspective view showing the configuration of the flux switching motor shown in FIG. 3 with the rotating shaft and armature coil omitted. FIG. 5 is a perspective view showing the configuration of the flux switching motor shown in FIG. 4 with the holder member omitted. FIG. 6 is a partially enlarged plan view showing the left side portion of the configuration shown in FIG. 5 in an enlarged manner. FIG. 7 is a sectional view taken along the line VII-VII in FIG. 6. FIG. 8 is a diagram corresponding to FIG. 3 showing a modification of the flux switching motor according to the embodiment.

Hereinafter, embodiments of the present disclosure will be described in detail based on the drawings. The following description of the embodiments is merely illustrative in nature and is not intended to limit the present disclosure, its applications, or its uses.

(fan motor)
FIG. 1 shows the entire fan motor 1 including a flux switching motor 10 according to an embodiment of the present disclosure. This fan motor 1 is mainly installed in a battery-powered vacuum cleaner (not shown) such as a cordless stick vacuum cleaner. The flux switching motor 10 according to this embodiment is configured as an inner rotor type flux switching motor.

In the following description, the fan motor 1 is referred to as the side where the fan cover 4 shown in FIGS. and represents the positional relationship in the vertical direction (corresponding to the axial direction P of the rotating shaft 20 described later) in the flux switching motor 10. Note that such a positional relationship has nothing to do with the actual vertical direction of the battery-powered vacuum cleaner equipped with the fan motor 1.

As shown in FIGS. 1 and 2, the fan motor 1 includes a housing 2, an impeller 3, a fan cover 4, a wiring board 5, and a flux switching motor 10. In this embodiment, the fan motor 1 preferably has a suction power of 250W or more.

The housing 2 includes a first housing 2a and a second housing 2b. The first housing 2a is arranged above the flux switching motor 10. On the other hand, the second housing 2b is arranged below the flux switching motor 10. The housing 2 is configured to cover the entire flux switching motor 10 in a state where the first housing 2a and the second housing 2b are combined with each other.

The impeller 3 is arranged above the first housing 2a. The impeller 3 has a main body portion 3a. The main body portion 3a is formed into a substantially conical shape. A fitting hole 3b for fitting a rotating shaft 20, which will be described later, is formed at approximately the center of the main body portion 3a in a plan view. A plurality of blade portions 3c, 3c, . . . are provided on the outer peripheral surface of the main body portion 3a.

The fan cover 4 is arranged above the first housing 2a so as to cover the impeller 3 from above. At approximately the center of the fan cover 4 in a plan view, an air intake port 4a is formed which opens in a substantially circular shape in the vertical direction.

The wiring board 5 is arranged below the second housing 2b. The wiring board 5 is electrically connected to each armature coil 50 that constitutes the flux switching motor 10, which will be described later. Capacitors 5a, 5a, . . . are provided on the lower side of the wiring board 5. Further, the wiring board 5 has a control for detecting the position of each rotor tooth 33, which will be described later, and controlling the energization state of the A-phase coils 51, 51, ... and B-phase coils 52, 52, ..., which will be described later. A circuit (not shown) is provided.

(flux switching motor)
The flux switching motor 10 is, for example, a two-phase AC flux switching motor. The flux switching motor 10 is configured to have an outer diameter of 100 mm or less and a total height of 50 mm or less.

(Axis of rotation)
As shown in FIGS. 1 to 3, the flux switching motor 10 includes a rotating shaft 20. As shown in FIGS. The rotating shaft 20 is formed to extend along the direction of a dashed line indicated by the symbol P (hereinafter referred to as "axial direction P"). The rotating shaft 20 is fixed to the rotor 30 while being inserted into a hole 32 of the rotor 30, which will be described later.

As shown in FIG. 2, the rotating shaft 20 is provided with bearings 21, 21. The bearings 21, 21 are arranged above and below the rotor 30, respectively.

(rotor)
As shown in FIG. 2, the flux switching motor 10 includes a rotor 30. The rotor 30 is made of a magnetic material such as iron. The rotor 30 is configured to be rotatable around the rotation shaft 20 in a circumferential direction of the rotation shaft 20 (hereinafter referred to as "circumferential direction").

As shown in FIGS. 3 to 7, the rotor 30 includes a yoke portion 31, a hole portion 32, and a plurality of rotor teeth 33, 33, .

The hole portion 32 is formed approximately at the center of the yoke portion 31 in a plan view, and penetrates in the axial direction P. The yoke portion 31 is fixed to the rotating shaft 20 with the rotating shaft 20 inserted into the hole 32.

Each rotor tooth 33 is formed integrally with, for example, the yoke portion 31, and protrudes outward from the yoke portion 31 in a radial direction (hereinafter referred to as “radial direction”) centered on the rotating shaft 20. An even number (six in the illustrated example) of the rotor teeth 33, 33, . . . are provided. The difference between the number of armature slots 46, 46, . . . , which will be described later, and the number of rotor teeth 33, 33, . . . is an even number.

The rotor teeth 33, 33, . . . are arranged at intervals in the circumferential direction. Specifically, the rotor teeth 33, 33, . . . are arranged at equal intervals in the circumferential direction so that each interval is 60°.

(stator)
As shown in FIG. 2, the flux switching motor 10 includes a stator 40. The stator 40 is made of a magnetic material such as iron. The stator 40 is arranged opposite to the rotor 30 so as to surround the outer periphery thereof.

As shown in FIGS. 3 and 4, stator 40 has a stator core 42. As shown in FIGS. A holder member 41 is attached to the stator core 42 . The stator core 42 is configured to have a substantially annular shape in a plan view when divided stators 43, 43, . . . , which will be described later, are combined with the holder member 41. Note that claw portions 41a, 41a for holding each armature coil 50, which will be described later, on each stator tooth 44 are formed on the upper surface of the holder member 41.

As shown in FIGS. 5 and 6, the stator core 42 includes a plurality of (eight in the illustrated example) divided stators 43, 43, . . . . Each divided stator 43 is formed into a substantially C-shape when viewed from above. Each divided stator 43 includes a yoke portion 43a and a pair of protrusions 43b and 43c.

The yoke portion 43a is arranged on the outside in the radial direction (that is, on the opposite side to the side where each rotor tooth 33 is located). The yoke portion 43a has an outer peripheral surface curved along the outer peripheral direction of the stator core 42. Each of the protrusions 43b and 43c protrudes radially inward from the circumferential end of the yoke portion 43a.

As shown in FIGS. 3 and 4, the stator 40 is provided with a plurality of stator teeth 44, 44, . . . . Each stator tooth 44 projects from the outside in the radial direction toward the inside. The stator teeth 44, 44, . . . are arranged at intervals in the circumferential direction. In the present embodiment, each stator tooth 44 is configured such that a protrusion 43b of one stator segment 43 and a protrusion 43c of the other stator segment 43 that oppose this protrusion 43b in the circumferential direction form a pair. has been done.

As shown in FIGS. 6 and 7, each stator tooth 44 is formed such that a radially inner tip 44a faces the tip 33a of each rotor tooth 33 with an air gap G interposed therebetween. ing. That is, each stator tooth 44 is arranged so that its tip 44 a does not come into contact with the tip 33 a of each rotor tooth 33 . This air gap G allows magnetic flux to be transferred between each stator tooth 44 and each rotor tooth 33.

As shown in FIGS. 5 and 6, the stator 40 is provided with a plurality of field slots 45, 45, . . . . Each field slot 45 is formed at a substantially central position in the circumferential direction of each stator tooth 44 . Specifically, each field slot 45 is configured as a space located between a protrusion 43b of one stator segment 43 and a protrusion 43c of the other stator segment 43 that faces this protrusion 43b in the circumferential direction. has been done.

As shown in FIGS. 4 to 6, the stator 40 is provided with a plurality of armature slots 46, 46, . . . . Each armature slot 46 is arranged between adjacent stator teeth 44 in the circumferential direction. Specifically, each armature slot 46 is configured as a space located between the protrusions 43b and 43c of one divided stator 43. The armature slots 46, 46, . . . are arranged alternately with the field slots 45 in the circumferential direction.

Note that in this embodiment, the two-phase motor has six rotor teeth 33, 33, . . . , so there are 6 pole pairs, or 12 poles, and the number of armature slots 46, 46, . . . is 8. For this reason, it has a fractional slot configuration, and the number of rotor teeth 33 and the number of armature slots 46 are both even numbers, and the difference between them is also an even number.

(armature coil)
As shown in FIGS. 2 and 3, the flux switching motor 10 includes a plurality of armature coils 50, 50, . Each armature coil 50 is made of flat wire and wound edgewise. The armature coils 50, 50, . . . are configured to form a magnetic field (hereinafter referred to as a "rotating magnetic field") for rotationally driving the rotor 30. Specifically, the rotating magnetic field is formed by supplying two-phase alternating current to each armature coil 50, and the rotating magnetic field is generated from the tip portion 44a of each stator tooth 44.

A plurality of armature coils 50, 50, . . . are provided on the stator 40. Specifically, each armature coil 50 is wound around the stator teeth 44 so as to straddle the field slot 45 located between a pair of armature slots 46, 46 adjacent to each other in the circumferential direction.

The armature coils 50, 50, . . . consist of a plurality (four in the illustrated example) of A-phase coils 51, 51, . The A-phase coils 51 and the B-phase coils 52 are arranged alternately in the circumferential direction.

Here, in this embodiment, the A-phase coil 51 is wound clockwise, and the B-phase coil 52 adjacent to this A-phase coil 51 is also wound clockwise. Further, the A-phase coil 51 adjacent to the B-phase coil 52 wound clockwise is wound counterclockwise, and the B-phase coil 52 adjacent to this A-phase coil 51 is also wound counterclockwise. There is. Further, the A-phase coil 51 adjacent to the B-phase coil 52 wound counterclockwise is wound clockwise, and the B-phase coil 52 adjacent to this A-phase coil 51 is also wound clockwise. .

(magnet)
The stator 40 has a plurality of (eight in the illustrated example) magnets 60, 60, . . . for applying a field to the rotor 30. Each magnet 60 is housed in each field slot 45. Each magnet 60 is an anisotropic Sm--Fe--N bond magnet configured to contain a resin content of 40% or more in volume %.

Here, for example, when an alternating current flows through the A-phase coils 51, 51, ..., each stator tooth 44 around which each A-phase coil 51 is wound becomes an electromagnet, and the rotor teeth located near the stator teeth It starts to attract 33.

Magnet 60 then includes a first end 61 and a second end 62 .

When each magnet 60 is housed in each field slot 45, the first end 61 is located on the radially outer side of the tip 44a of each stator tooth 44 (on the opposite side to the side where each rotor tooth 33 is located). ). That is, each magnet 60 is located radially outside the tip 44a of each stator tooth 44 in plan view. In other words, each magnet 60 is accommodated in each field slot 45 such that the first end 61 is not flush with the tip 44a of each stator tooth 44.

The circumferential position of the first end portion 61 is arranged such that the distance from the rotor tooth 33 is longer than the tip portion 44 a of the stator tooth 44 facing the rotor tooth 33 . A fillet is provided at the outer corner of the first end 61.

The second end 62 is formed to be located on the outer side of the first end 61 in the radial direction (on the opposite side to the side where each rotor tooth 33 is located).

The circumferentially adjacent magnets 60, 60 are arranged such that magnetic pole faces of the same polarity face each other in the circumferential direction. This causes one magnet 60 to repel the other magnet 60 between the circumferentially adjacent magnets 60 .

Each magnet 60 is formed to taper from the outside in the radial direction to the inside in a plan view. Specifically, as shown in FIG. 6, each magnet 60 has a width in the circumferential direction at the second end 62 (dimension W2 shown in FIG. 6) and a width in the circumferential direction at the first end 61 (dimension W2 shown in FIG. It is formed to be larger than the dimension W1) shown.

[Characteristic configuration of this embodiment]
As a feature of this embodiment, as shown in FIG. 7, the length of the stator 40 in the axial direction P (dimension L2 shown in FIG. It is configured to be shorter than the dimension L3). Specifically, each divided stator 43 is formed such that its upper end is located below the upper end of the magnet 60 and its lower end is located above the lower end of the magnet 60 on the paper surface of FIG. ing.

On the other hand, the rotor 30 is configured such that its axial length (dimension L1 shown in FIG. 7) is shorter than the length (L2) of the stator 40 in the axial direction P. Specifically, the rotor 30 is formed such that its upper end is located below the upper end of the stator 40 and its lower end is located above the lower end of the stator 40 on the paper of FIG. has been done.

[Operations and effects of embodiment]
As described above, in the present embodiment, the length of the stator 40 in the axial direction P of the rotating shaft 20 is shorter than the length of the axial direction P of the magnet 60, while the length of the rotor 30 in the axial direction P is shorter than the length of the axial direction P of the magnet 60. The length of the stator in the axial direction P is less than or equal to the length of the stator in the axial direction P. In this configuration, the overhang of the magnet 60 with respect to the stator 40 reduces leakage magnetic flux in the axial direction P near the boundary between the stator 40 and the magnet 60. That is, the loop path of leakage magnetic flux from the end face of the stator 40 in the axial direction P to the end face of the magnet 60 in the axial direction P is blocked, and the magnetic flux flowing to the stator 40 increases. As a result, the magnetic flux that contributes to higher output due to increased torque increases. Furthermore, due to the overhang of the stator 40 with respect to the rotor 30, the gap magnetic flux density of the air gap G increases, the magnetic flux flowing to the rotor 30 increases, and the magnetic flux that contributes to higher output due to increased torque increases. Furthermore, since the length of the axial direction P in both the rotor 30 and the stator 40 is shorter than the length of the axial direction P in the magnet 60, it is possible to reduce the overall size of the motor, and the flux switching motor 10 Miniaturized. Furthermore, by making the sizes of the rotor 30 and stator 40 relatively small, it is possible to suppress the weight of the material (for example, iron material as a magnetic material) that constitutes the rotor 30 and stator 40, and the flux The switching motor 10 is extremely lightweight. Therefore, in this embodiment, it is possible to obtain a flux switching motor 10 that achieves both high output, miniaturization, and ultra-light weight.

Further, the plurality of magnets 60, 60, . The first end 61 is arranged on the side closer to the rotor 30 in the radial direction, and the second end 62 is arranged on the far side, and the circumferential width at the second end 62 is the same as the circumferential width of the first end 61. It is designed to be longer than the That is, when the flux switching motor 10 is viewed planarly in the axial direction of the rotating shaft 20, the outer shape of the magnet 60 becomes a substantially trapezoidal shape that tapers toward the side where the rotor 30 is located. As a result, the surface area of the circumferentially facing side portion of the magnet 60 becomes relatively large, and the contact area between the stator 40 and the magnet 60 increases. As a result, the magnetic flux generated from the magnet 60 easily flows to the stator 40. Therefore, the magnetic flux of the magnet that excites the rotor 30 becomes higher, and the output can be further increased.

Further, the circumferential position of the first end 61 of the magnet 60 is arranged such that the distance from the rotor teeth 33 is longer than the end of the stator teeth 44 facing the rotor teeth 33. A fillet is provided at the outer corner of the first end 61. This reduces the amount of magnet 60 exposed to fringing magnetic flux generated between stator teeth 44 and rotor teeth 33 and leakage magnetic flux from stator teeth 44, resulting in irreversible demagnetization, that is, a decrease in magnetic force. Since the output of the flux switching motor 10 can be suppressed, the output of the flux switching motor 10 can be stabilized, and a deterioration in the performance of the flux switching motor 10 can be suppressed. In addition, since the eddy current generated when the fringing magnetic flux passes through the magnet 60 can be similarly reduced, it is also possible to improve the efficiency of the flux switching motor 10.

In addition, in an anisotropic Sm-Fe-N bonded magnet configured to contain a resin content of 40% or more in terms of volume%, while the resin content is relatively large, the iron content is relatively large. will be less. Therefore, the loss of eddy current generated in the magnet 60 due to the magnet 60 containing iron is reduced, so efficiency can be increased, and the amount of iron, copper, and magnet can be reduced to increase efficiency. As a result, the weight can be reduced by the amount of material used. Further, the specific gravity (4.5 g/cm ³ ) of the anisotropic Sm--Fe--N bond magnet is smaller than, for example, the specific gravity (6.5 g/cm ³ ) of the Nd--Fe--B bond magnet. Therefore, by applying the anisotropic Sm--Fe--N bonded magnet, it is possible to obtain the magnet magnetic flux of the desired strength, while reducing the weight of the magnet 60 compared to, for example, a Nd--Fe--B bonded magnet. This makes it possible to suppress the increase in Therefore, by applying the above-described anisotropic Sm--Fe--N bonded magnet to the flux switching motor 10, the weight of the motor can be further reduced.

In addition, in this embodiment, the flux switching motor 10 having an outer diameter of 100 mm or less and an overall height of 50 mm or less is used as a fan motor for mounting on a battery-powered vacuum cleaner that is small and lightweight and requires high suction power. It can be applied as one component.

Further, in this embodiment, the number of rotor teeth 33, 33, ... is an even number, and the difference between the number of armature slots 46, 46, ... and the number of rotor teeth 33, 33, ... is also an even number. This makes it possible to prevent eccentric rotation. As a result, noise and vibration caused by the motor can be suppressed.

Further, in this embodiment, it is possible to obtain a fan motor 1 that is small and lightweight and can be applied to a battery-powered vacuum cleaner that has high suction power.

Furthermore, in this embodiment, since the suction power of the fan motor 1 is 250 W or more, the fan motor 1 can be applied to a battery-powered vacuum cleaner that requires high suction power.

Furthermore, the battery-powered vacuum cleaner equipped with the fan motor 1 according to this embodiment is small and lightweight, and can exhibit high suction power.

[Modification of embodiment]
In the above embodiment, the flux switching motor 10 using two-phase alternating current is shown, but the present invention is not limited to this form. For example, the flux switching motor 10 may have a single-phase AC configuration, as in the modification shown in FIG. Specifically, in this modification, the configurations of the rotor 30 and armature coils 50, 50, . . . are partially different from those of the above embodiment. Note that the other configurations in this modification are the same as those in the above embodiment, so detailed explanations will be omitted.

As shown in FIG. 8, each armature coil 50 of this modification is configured to be supplied with single-phase alternating current. That is, the armature coils 50, 50, . . . of this modification do not have the distinction of being an A-phase coil and a B-phase coil as in the above embodiment.

Further, in the rotor 30 of this modification, four rotor teeth 33, 33, . . . are provided, unlike the above embodiment. Specifically, the rotor teeth 33, 33, . . . are arranged at regular intervals such that each interval is 90° in the circumferential direction. In such a modified example, since the number of poles of the rotor teeth 33, 33, ... is reduced in comparison with the above embodiment, it is possible to lower the switching frequency for switching energization to the motor coil during motor drive. . This reduces the processing power of the microcomputer and the switching loss of power elements such as FETs. As a result, the manufacturing cost of the motor can be reduced and the efficiency of the motor can be increased.

Even in this modification, if the single-phase AC flux switching motor 10 is provided with each magnet 60 including the first end 61 and the characteristic configuration of the above embodiment (see FIG. 7), the above-mentioned The same effects as in the embodiment can be achieved.

[Other embodiments]
In the above embodiment, the flux switching motor 10 is configured as an inner rotor type, but the present invention is not limited to this type. That is, the flux switching motor 10 may be configured as an outer rotor type .

Further , in the above embodiment, each magnet 60 is an anisotropic Sm-Fe-N bonded magnet configured to contain a resin content of 40% or more in volume%. Not limited.

Furthermore, in the embodiment described above, the stator core 42 is composed of a plurality of divided stators 43, 43, . . . , but the stator core 42 is not limited to this embodiment. That is, the stator core 42 may be formed by integrally forming the divided stators 43, 43, . . . .

Although the embodiments of the present disclosure have been described above, the present disclosure is not limited to the above-described embodiments, and various changes can be made within the scope of the invention.

The present disclosure can be used industrially as a flux switching motor to be installed in a battery-powered vacuum cleaner such as a cordless stick vacuum cleaner, a fan motor using the same, and a battery-powered vacuum cleaner.

1: Fan motor 10: Flux switching motor 20: Rotating shaft 30: Rotor 33: Rotor teeth 40: Stator 42: Stator core 43: Split stator 43a: Yoke parts 43b, 43c: Projecting part 45: Field slot 46: Armature slot 50: Armature coil 51: A phase coil 52: B phase coil 60: Magnet 61: First end 62: Second end P: Axial direction G: Air gap

Claims (7)

a rotating shaft;
a rotor having a plurality of rotor teeth rotatable around the rotation axis;
a plurality of stator teeth each facing each of the plurality of rotor teeth via an air gap; a plurality of armature slots and a plurality of field slots arranged alternately; a stator having a plurality of magnets arranged in each of the slots, and an armature coil wound around each of the armature slots so as to straddle each of the magnets,
The stator has an axial length that is shorter than the axial length of the magnet, and the rotor has an axial length that is shorter than the axial length of the stator. It is configured to be shorter than the
The upper end of the rotor is located below the upper end of the stator, and the upper end of the stator is located below the upper end of each magnet,
The lower end of the rotor is located above the lower end of the stator, and the lower end of the stator is located above the lower ends of each of the magnets. The flux switching motor according to claim 1,
The plurality of magnets are each housed in each of the field slots and are arranged so that magnetic pole surfaces of the same polarity face each other in the circumferential direction,
Each of the magnets has a first end on a side closer to the rotor in a radial direction with respect to the rotation axis, and a second end on a side farther from the rotor, and the width in the circumferential direction at the second end is The flux switching motor is formed to be longer than the width of the first end in the circumferential direction. The flux switching motor according to claim 2,
The first end of the magnet is arranged such that a radial position around the rotation center of the rotating shaft is located radially outward from a radial position of the end of the stator teeth. and
A flux switching motor, wherein a fillet is provided at an outer corner of the first end. The flux switching motor according to any one of claims 1 to 3,
The magnet is an anisotropic Sm--Fe--N bonded magnet configured to contain a resin content of 40% or more in terms of volume. The flux switching motor according to any one of claims 1 to 4 ,
The rotor teeth are provided in an even number,
A flux switching motor in which the difference between the number of armature slots and the number of rotor teeth is an even number. A fan motor equipped with the flux switching motor according to any one of claims 1 to 5 . A battery-powered vacuum cleaner equipped with the fan motor according to claim 6 .

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