JP2000197287A - Motor and its manufacture - Google Patents

Abstract

PROBLEM TO BE SOLVED: To reduce the weight of a rotor to increase the efficiency and the power of a motor by using a material of a small magnetic permeability for the rotor to prevent the distribution of a magnetic flux in the main body of the rotor. SOLUTION: Body 1a of a rotor is made of a material of a small permeability having a small magnetic permeability and a small conductivity. Permanent magnets 2, 3 are disposed around the body of a rotor and then a rotor yoke 1b made of a material of a small magnetic permeability is disposed around the permanent magnets 2, 3 to form a rotor 1. A magnetic flux is scarcely distributed in the rotor 1 made of the material of a small magnetic permeability. As a result, there is no short-circuit generated between each two adjacent basic magnets and therefore the rotor can be reduced in weight and consequently a motor having the increased efficiency can be obtained.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a motor including a rotor and a stator. More specifically, the present invention relates to a motor whose rotor is reduced in weight and whose efficiency is improved.

[0002]

2. Description of the Related Art Normally, there are two types of rotors used for motors, an inner rotor type shown in FIG. 17 and an outer rotor type shown in FIG. FIG. 17 is an explanatory view schematically showing a plan cross section of the inner rotor type motor, and FIG. 18 is an explanatory view schematically showing a plan cross section of the outer rotor type motor.
In FIG. 18, the rotation shaft of the outer rotor is inserted into a through hole 90 at the center of the stator 99, but the rotation shaft and the like are not shown.

As shown in FIG. 17, the inner rotor type has a structure in which single pole magnetized magnets 92 and 93 are alternately arranged on the outer peripheral side of a rotor yoke 91 so as to face a stator 94. Has become. FIG.
As shown in FIG. 8, the outer rotor type has a structure in which single-pole magnetized magnets 97 and 98 are alternately arranged inside a rotor yoke 96 so as to face the stator 99. These rotor yokes 91 and 96 are
In general, for example, the rotor yokes 91 and 96 are formed of a material having high magnetic permeability (hereinafter, referred to as “high magnetic permeability material”) such as a laminated silicon steel sheet. It is generally considered essential to efficiently form a magnetic field structure.

Generally, in order to improve the efficiency of a motor by forming an efficient magnetic field structure, for example, a magnetic flux generated by a permanent magnet in a motor having a structure in which a permanent magnet is embedded in a rotor made of the high magnetic permeability material is used. It is conceivable to increase the amount and maximize the torque generated at the same current by using the magnet torque more efficiently. A motor based on this idea has been proposed in, for example, Japanese Patent Application Laid-Open No. 10-191585. I have.

According to the above-mentioned publication, as shown in FIG. 19, a conventional motor (internal permanent magnet) in which a permanent magnet 82 is embedded in a rotor body 81 made of a high magnetic permeability material such as iron.
20, an IPM type motor), as shown in detail in FIG. 20, a leakage L of magnetic flux occurs in a portion of both ends of the permanent magnet 82 close to the outer peripheral portion of the rotor 81. The problem is to improve the loss due to

According to the above publication, the invention described in the above publication has a structure in which a main magnet 87 and an auxiliary magnet 88 are embedded as permanent magnets inside a rotor 86 as shown in FIG. Regarding the arrangement of each permanent magnet in the permanent magnet embedded motor, the direction from S to N is referred to as the polarity direction, and the auxiliary magnet having a polarity direction perpendicular to the polarity direction of the main magnet 87. No. 88 is arranged to form a magnetic field and increase the amount of magnetic flux generated by the permanent magnet.

At this time, it is important that a high magnetic permeability material is disposed as a main body of the rotor 86 between the permanent magnets so as to strengthen the lines of magnetic force. The arrangement of the permanent magnets for strengthening the lines of magnetic force is generally known as an arrangement for obtaining a strong magnetic field.

However, in the permanent magnet embedded motor described in the above publication, for example, the auxiliary magnet 8 of the permanent magnet is used.
The lines of magnetic force are short-circuited between 8a and 88b,
There is a hindrance to improving efficiency. Therefore, in such a permanent magnet embedded motor, in order to overcome this short circuit,
There is a problem that a complicated driving method that can compensate for the short circuit of the magnetic field lines is required.

Regarding the improvement of the efficiency, apart from the problem of the short-circuit of the magnetic field lines, a high magnetic permeability material such as a silicon steel sheet generally has a high specific gravity and a heavy rotor weight. If you want to compare, the heavy weight,
There is a problem that the improvement in efficiency is hindered. That is,
Even if many lines of magnetic force can be generated, there is a problem that it is difficult to improve the efficiency because of the heavy weight of the rotor because the rotor is heavy.

It is conceivable to reduce the weight of the rotor material in order to cope with the heavy rotor weight. However, if a material other than the above-described silicon steel plate is used, the amount of magnetic field lines generated by the rotor decreases. It is difficult to obtain a desired torque.

[0011]

SUMMARY OF THE INVENTION The present invention has been made in order to solve such a problem, and a material having a small magnetic permeability (relative magnetic permeability) can be used for the rotor body to reduce the weight of the rotor and reduce the magnetic force. It is an object of the present invention to provide a motor with improved efficiency and power without a decrease and a method for manufacturing the same.

[0012]

In order to solve the above-mentioned problems, the present invention provides a rotor main body, which is a main part of the rotor, using a material having a low magnetic permeability as a material of the rotor.
Magnetic flux is not distributed to a portion made of this material, and a permanent magnet is arranged on the outer peripheral portion of the portion so as not to generate leakage magnetic flux and to prevent short circuit, thereby forming a magnetic field structure. The motor is realized by configuring the rotor. Hereinafter, in this specification, a material having a small magnetic permeability, that is, a material having no magnetism (a non-magnetic material) is referred to as a low magnetic permeability material.

The motor according to the first aspect of the present invention comprises an inner rotor 1 on which 2M permanent magnets are mounted, and a stator 4, wherein M is a positive even number. It is characterized in that a material having a small magnetic permeability is used as the material. With such features,
A structure in which the magnetic flux is hardly distributed in the rotor main body 1a can be realized.

In the motor according to the second aspect of the present invention, since the resin is used as the material, the weight of the rotor body can be reduced.

In the motor according to the third aspect of the present invention, since polybutylene terephthalate is used as the resin, the weight of the rotor body can be reduced, and mechanical strength, electrical insulation, and workability such as cutting are excellent. Rotor can be formed.

In the motor according to claim 4 of the present invention, the 2M permanent magnets are arranged such that the magnetic lines of force formed by the 2M permanent magnets are not distributed in the material. Obtain a magnetic field with a high magnetic flux density.

In the motor according to claim 5 of the present invention, of the 2M permanent magnets, each of the M first permanent magnets 2 is maintained at a predetermined interval, and the direction of each polarity is changed. The rotor body 1a is disposed so that a radial outward direction and a radial inward direction are sequentially opposite to each other,
In addition, a second permanent magnet 3 is provided between each pair of adjacent two first permanent magnets 2, and the polarity of the second permanent magnet 3 is changed along the circumferential direction. Are arranged so as to have the same polarity as the polarity of the magnetic pole on the outside, thereby obtaining a magnetic field having a high magnetic flux density.

In the motor according to claim 6 of the present invention, for example, the shape of the first permanent magnet 2 can be rectangular, and the shape of the second permanent magnet 3 can be trapezoidal.
In addition, a magnetic field having a high magnetic flux density can be realized by disposing permanent magnets having a simple shape such as a rectangular shape.

In the motor according to claim 7 of the present invention, since the first permanent magnet 2 and the second permanent magnet 3 are mounted on the surface of the rotor body 1a, the magnetic flux generated by the permanent magnet is reduced. It can contribute to rotation as it is.

In the motor according to claim 8 of the present invention, the first permanent magnet 2 and the second permanent magnet 3 are mounted in the recess 11 provided on the surface of the rotor body 1a. The permanent magnet does not fall off due to the rotation of the rotor.

In the motor according to the ninth aspect of the present invention, since the first permanent magnet 2 and the second permanent magnet 3 are embedded in the rotor 1, the permanent magnet may fall off due to rotation. There is no.

In the motor according to the tenth aspect of the present invention, since a material having high magnetic permeability is used for the portion of the rotor body 1a on the side of the rotor shaft 1x, the mechanical strength can be enhanced.

In the motor according to the eleventh aspect of the present invention, since the hollow portion 1y penetrating the rotor main body 1a is provided, the weight of the rotor can be further reduced.

In the motor according to the twelfth aspect of the present invention, since the rotor body 1a is formed in a shape having the spokes 1z, the rotor can be further reduced in weight.

According to a thirteenth aspect of the present invention, there is provided a motor comprising:
Is a positive even number, an outer-type rotor 6 having 2M permanent magnets attached thereto, and a stator 9
Since a material having a small magnetic permeability is used as the material of the rotor main body 6a, almost no magnetic flux is distributed in the rotor main body 6a.

According to a fourteenth aspect of the present invention, there is provided a motor manufacturing method comprising: an inner rotor 1 on which 2M permanent magnets are mounted; and a stator 4, wherein M is a positive even number. A method for manufacturing a motor using a material having a small magnetic permeability as a material of a main body 1a, comprising: a step of forming the stator 4; a step of forming the rotor body 1a; And a step of assembling the stator 4 and the rotor main body 1a on which 2M permanent magnets are mounted. With such a feature, it is possible to form a motor with improved efficiency using a low magnetic permeability material.

In the method for manufacturing a motor according to the fifteenth aspect of the present invention, since the rotor main body 1a and the 2M permanent magnets are formed by an integral molding method, there is no need for an assembling step of attaching the permanent magnets to the rotor.

According to the method of manufacturing a motor according to claim 16 of the present invention, the recesses 11 are provided at predetermined positions of the rotor main body 1a, and the 2M permanent magnets are attached to each of the recesses 11. The rotor body can be formed by the mold.

The method for manufacturing a motor according to claim 17 of the present invention is characterized in that the 2M permanent magnets are attached to predetermined positions of the rotor main body 1a, respectively, and the attached 2M permanent magnets are attached.
Since the rotor is formed by covering the outer peripheral side of the individual permanent magnets with the ring-shaped member 12, the rotor yoke can be formed without the need for a mold or the like.

[0030]

Embodiments of the present invention will be described below with reference to the accompanying drawings.

Embodiment 1 FIG. 1 is an explanatory plan sectional view conceptually showing the structure of an inner rotor type motor according to an embodiment of the present invention.
FIG. 2 is an explanatory plan sectional view conceptually showing an arrangement of a configuration including a direction of a polarity of a permanent magnet used in the inner rotor type motor. FIG. 3 has a rotor yoke 1b shown in FIG. It is a plane sectional explanatory view showing an example which does not do.

In this embodiment, the rotor main body 1a is made of a low magnetic permeability material having a small magnetic permeability and a small electric conductivity, and permanent magnets 2 and 3 are arranged around the rotor main body 1a. A motor in which the rotor 1 is formed by disposing the low-permeability material as the rotor yoke 1b also on the outer peripheral side thereof will be described.

The permanent magnet is a first permanent magnet,
Rectangular permanent magnets (hereinafter referred to as basic magnets) 2
a and 2b and eight trapezoidal permanent magnets (hereinafter, referred to as auxiliary magnets) 3a and 3b as second permanent magnets are alternately arranged, and the basic magnets 2a and 2b are evenly distributed on the outer peripheral side of the rotor body 1a. The N pole faces outward (2
a) and the S pole are arranged to alternately repeat outward (2b). The auxiliary magnets 3a and 3b are connected between the basic magnets 2a and 2b. Along the outer circumference of the main body 1a, the magnetic poles of the outer magnetic poles of the basic magnet and the magnetic poles of the auxiliary magnet opposed thereto are arranged to have the same polarity and to be adjacent to each other.

The shape of the first permanent magnet 2 and the shape of the second permanent magnet 3 are not limited to the above-mentioned shapes. For example, the first permanent magnet 2 and the second permanent magnet 3 are Both can be rectangular or trapezoidal in shape, and the shape and the above-mentioned arrangement can be determined by changing within a range that satisfies the requirements for magnetic flux distribution described later.

In this embodiment, these basic magnets 2a and 2b and auxiliary magnets 3a and 3b
Further, the low magnetic permeability material is provided as the rotor yoke 1b also on the outer peripheral side of the above, and the entire structure is provided in the low magnetic permeability material. At this time, the intervals between the permanent magnets may be close to each other, or a predetermined interval may be adopted. The number M of basic magnets and the number M of auxiliary magnets (M is a positive even number) can be arbitrarily set as long as they can be arranged symmetrically in a plan view.

As the low magnetic permeability material, a nonmagnetic material having a small magnetic permeability other than a material conventionally known as a so-called high magnetic permeability material and an insulating material having a small electric conductivity can be used. . That is, in the low magnetic permeability material, the magnetic flux generated by the basic magnet and the auxiliary magnet is hardly distributed. Moreover, a material having a small specific gravity is preferable.

First, from the electromagnetic point of view, high magnetic permeability μs
As the high magnetic permeability material (0.01 × 10E3 to 100 × 10E3) having silicon, silicon steel plate (5000 to 17000), permalloy NiF
e alloys (2500 to 5000), CoFe alloys, MnZn ferrites, and the like are known. When a magnetic field is present outside, these materials are likely to distribute magnetic flux in the material. It is not preferable as a material. Further, materials having high conductivity such as silver, copper, tungsten, and iron are not preferable because they generate eddy currents when the rotor rotates and reduce the efficiency. However, a sheet obtained by laminating these high-conductivity materials into thin plates, such as a conventional laminated silicon steel sheet, does not generate eddy current and can be used. In the embodiment described in the second embodiment, the high magnetic permeability material can be used as a material of the rotor body according to the present invention.

In addition to the electromagnetic viewpoint, a material having a small weight (that is, specific gravity) and a large mechanical strength is preferable.

As an example of a material satisfying such requirements for the material of the rotor body according to the present invention, first, resin and rubber can be cited. Among these, as general resin materials, polyacetal (POM), polyamide (PA), polycarbonate (PC), polybutylene terephthalate (PBT), polyacrylate (PAR), polyimide (PI), polypropylene (PP) ,polystyrene
(PS), AS resin (AS), ABS resin (ABS), polyethylene terephthalate (PET), polyphenylene sulfide (PPS), polyamideimide (PAI), polymethylpentene (TPX) and the like. As a material having a somewhat special property, there are a resin containing fluorine such as polytetrafluoroethylene (PTFE), a silicon resin (SI), a phenol resin (PF), and an epoxy resin (EP). Butadiene rubber (BR), silicone rubber (Q), ethylene propylene copolymer elastomer (E
PM).

These resins and rubbers are excellent in mechanical strength, electrical insulation, voltage resistance, heat resistance, wear resistance, etc.
Because of good workability, it is preferable as a material for the rotor according to the present invention. Further, porcelain materials such as alumina and silicon carbide, and carbon and glass as structural materials are also preferable from the viewpoint of electromagnetic properties, mechanical strength, and wear resistance.

Further, a mixture of several kinds of these resins and rubbers, or any of these resins and rubbers, or a mixture of plural kinds of materials among them may be mixed with an inorganic substance such as mica or glass. Alternatively, a material obtained by adding a material such as a metal material, a resin, a rubber, or a combination thereof in the form of a particle, a fiber, a rod, or the like as a filler may be used. Conversely, the rotor body may be configured to include a bubble-shaped cavity. further,
The above example is for a typical material of a composite,
Natural products such as natural rubber and wood can also be used.

The reason that the various materials as described above are required to have low magnetic permeability is that the magnetic flux is hardly distributed in these materials. Also, the reason that the conductivity is required to be small is that a material having a large conductivity generates an eddy current inside when rotated as a rotor, weakens the magnetic force, and suppresses the rotation of the rotor. That's why. As described above, from the viewpoint of preventing eddy currents, the rotor body may be formed by laminating a silicon steel plate or the like into a thin plate and laminating it. Can not be obtained.

Similarly to the case of the inner type rotor, the outer type rotor shown in FIGS. 4, 5 and 6 also has a low magnetic permeability and a low magnetic permeability material having a small electric conductivity. An outer peripheral portion 6a of the main body is formed, and permanent magnets 7 and 8 are disposed on the inner peripheral side. In the case of the example shown in FIG. 6, the low magnetic permeability material is further provided on the inner peripheral side as a rotor yoke 6b. Was arranged.

As in the case of the inner-type rotor, the permanent magnets include eight rectangular permanent magnets (hereinafter, referred to as basic magnets) 7a and 7b as first permanent magnets and second permanent magnets. Eight trapezoidal permanent magnets (hereinafter, referred to as auxiliary magnets) 8a and 8b are alternately arranged, and the basic magnets 7a and 7b are equally spaced on the circumference of the rotor so that the N pole faces outward (7a). , S pole outward (7
b) are alternately repeated, and the auxiliary magnets 8a and 8b are connected between the basic magnets 7a and 7b. The direction of the polarity of the auxiliary magnets is along the outer peripheral direction of the rotor body, and And the same polarity pole of the auxiliary magnet are arranged adjacent to each other.

The distribution of magnetic flux when the rotor main body is made of a low magnetic permeability material as described above will be described in detail below.

FIG. 7 shows a rotor body 6a made of a resin material.
FIG. 9 is a schematic diagram schematically showing a magnetic flux distribution in the vicinity of an inner peripheral surface and an outer peripheral surface of a rotor in an outer rotor type motor in which only basic magnets 97a and 97b are provided. FIG. 8 shows an outer rotor type motor in which only basic magnets 97a and 97b are disposed on a conventional rotor main body 96a made of iron, which can be compared with FIG. It is the schematic diagram which showed distribution schematically. The arrow in the figure indicates the direction of the polarity.

FIG. 9 shows an outer rotor type motor in which basic magnets 7a and 7b and auxiliary magnets 8a and 8b are disposed on a rotor body 6a made of a resin material according to the first embodiment. It is the schematic diagram which showed roughly the magnetic flux distribution in the vicinity and the outer periphery side surface vicinity. FIG. 10 shows a first embodiment in which basic magnets 7a and 7b and auxiliary magnets 8a and 8b are provided on a rotor main body 96a made of conventional iron which can be compared with FIG.
FIG. 4 is a schematic diagram schematically showing a magnetic flux distribution in the vicinity of the inner peripheral surface and the outer peripheral surface of the rotor in the outer rotor type motor arranged according to FIG.

In the motor according to the prior art, since iron such as a silicon steel plate is used for the material of the rotor in order to strengthen the magnetic force in the rotor, a short circuit occurs between the permanent magnets 7a and 7b as described above ( On the other hand, in the present embodiment, there is no magnetic substance between the permanent magnets and a low-permeability material, so that
A short circuit hardly occurs (see the magnetic flux shown in 6a of FIG. 9). Therefore, the magnetic flux generated by the permanent magnet can be concentrated on the stator side, and the concentrated magnetic flux can be almost entirely used for rotation with the opposed stator.

9 and 10, the magnetic flux distribution on the stator side surface of the outer type rotor according to this embodiment is equivalent to that of the conventional outer type rotor using iron. It can be seen that the magnetic flux density is sufficient. FIG. 11 is a graph showing this in more detail over an electrical angle of 0 to 360 degrees.
In the same figure, a broken line with a square plot shows a case of a resin rotor in which only the basic magnet is provided, and a broken line shows a case of an iron rotor in which only the basic magnet is provided,
The solid line shows the case of the resin rotor provided with the basic magnet and the auxiliary magnet, and the solid line with the round plot shows the case of the iron rotor provided with the basic magnet and the auxiliary magnet. As shown in the figure, it can be seen that a sufficiently high magnetic field equivalent to that of the conventional rotor is obtained.

As shown in FIG. 9, since the amount of magnetic flux distribution outside the rotor body 6a is small, as shown in FIG.
Without using iron for the rotor body 6a, the rotor body 6a
It can be seen that the distribution of the magnetic flux can be reduced outside the graph.

Further, since the inside of the rotor is made of a synthetic resin having a small specific gravity, the weight of the rotor can be reduced, and the efficiency and the power can be further improved.

From the viewpoint described above, in the present embodiment, the rotor body is formed by using a synthetic resin such as polybutylene terephthalate. As a result, the magnetic force can be enhanced by using the auxiliary magnet, a short-circuit does not occur between two adjacent basic magnets, the weight can be reduced as compared with the conventional rotor, and a motor with improved efficiency can be obtained. Generally, the efficiency of a motor is often evaluated at a certain number of rotations with respect to a predetermined voltage input, but improved efficiency including a contribution to weight reduction is obtained.

A method of manufacturing a motor using the rotor according to the embodiment described above will be described. The stator is manufactured according to a conventionally known technique.
The rotor according to the present embodiment has a form in which a permanent magnet is embedded in a synthetic resin. FIG. 12 is a perspective explanatory view conceptually showing a manufacturing method in which a permanent magnet is integrally embedded in a synthetic resin.

As shown in FIG. 12, the basic magnets 2a and 2b and the auxiliary magnets 3 are formed in a predetermined shape.
The permanent magnets a and 3b are set with an appropriate jig or the like, and synthetic resin is injected into the periphery of the permanent magnets using a predetermined mold or the like by an injection molding method or the like, so as to be integrated with the permanent magnets. The rotor 1 is formed. At this time, the resin injection may be divided into two steps, and the jig and the like may be omitted. Thereafter, the stator 4 and the rotor 1 are assembled. By adopting the manufacturing method in which the rotor 1 is integrally formed in this manner, the step of manually assembling the rotor 1 is unnecessary, and the manufacturing cost is reduced, so that the motor according to the present invention can be provided at low cost.

FIG. 13 shows a concave portion 11 (only one portion is shown in FIG. 13) into which permanent magnets of the basic magnets 2a and 2b and the auxiliary magnets 3a and 3b formed in the predetermined shape can be inserted. A molded body of the synthetic resin is formed in advance, and after the formation, the permanent magnet 2a is
After inserting ', a perspective description conceptually showing a manufacturing method of an assembling mold in which the rotor upper 1c and the rotor lower 1d, which are disk-shaped members made of the synthetic resin, are attached to the rotor 1 from the upper surface and the lower surface. FIG. According to such a manufacturing method, the mounting to the concave portion 11 can be performed by selecting any one of various methods such as bonding, press-fitting, and filling according to the design of the permanent magnet and the entire rotor.

Further, the material of the rotor upper case 1c and the rotor lower case 1d, which are the disc-shaped members, may be the same as or different from that of the molded body, and the peripheral portion of the rotor may be easily attached to the rotor body. May be provided with a step, and the upper rotor 1c and the lower rotor 1d may be stepped in correspondence with the step.

As described above, by adopting the manufacturing method in which the concave portion 11 is provided in the molded body and the permanent magnet is inserted and attached, the rotor body is formed by a mold that is less expensive than the case of integrally molding. Therefore, it is possible to produce a small number of motors of various kinds in a short delivery time by an assembling process.

In the description of the present manufacturing method, the concave portion 1
1 is provided so as to be concave from the upper surface of the rotor 1 to the lower surface. However, a concave portion may be provided in the rotor axial direction (along the radial direction) from the outer peripheral surface of the rotor 1 main body and the permanent magnet may be similarly attached. Good.

FIG. 14 is a perspective explanatory view showing a manufacturing method of obtaining a rotor by attaching a ring-shaped member 12 around the permanent magnet after attaching the permanent magnet to the rotor 1 main body. As shown in FIG. 14, when fitting the ring-shaped member 12,
A filler may be interposed between the ring-shaped member 12 and the permanent magnet, or may be bound by the rubber-shaped ring-shaped member 12.

According to the manufacturing method using the ring-shaped member 12 as described above, the rotor 1 can be formed without preparing a special rotor mold. When attaching the permanent magnet to the rotor body, it is a requirement that the permanent magnet does not fall off during rotation as the rotor, and the permanent magnet may be adhered to the rotor body, or attached so as to fit. Is also good.

In the above embodiment, the outer peripheral side of the permanent magnet is coated with the same material as the rotor body, but the effect of the present invention can be obtained without such coating. FIGS. 3 and 5 show a motor having a configuration in which the permanent magnet has no coating on the stator side, that is, has no rotor yoke, and is directly opposed to the stator. Since there is no coating on the stator side of the permanent magnet, a magnetic flux distribution can be obtained as it is with the arrangement of the permanent magnet, and there is no influence on the magnetic flux distribution. Such a rotor can be easily formed without the ring-shaped member 12 in a manufacturing method in which the ring-shaped member 12 is fitted around the rotor.

Second Embodiment In the first embodiment, the rotor shaft side of the rotor main body, that is, the center of rotation is an integral structure made of the synthetic resin material or the like. Since the magnetic flux is not distributed therein, the central portion near the rotor shaft can be formed using a material different from that of the rotor body. That is, a material having a high magnetic permeability such as a conventional silicon steel plate may be used for the central portion, or a material selected to improve the strength of the structure may be used.

In such a rotor, after the above-mentioned center portion is formed by metal working or the like in the same manner as the conventional rotor,
What is necessary is just to form so that the rotor main body of a synthetic resin etc. may be further attached.

By using the same iron-based metal material as that of the conventional rotor in the center of the rotor body, the strength of the rotor can be enhanced. Other points are the same as in the first embodiment.

Embodiment 3 In Embodiments 1 and 2, a low magnetic permeability material such as a synthetic resin is disposed on the rotor shaft side of the rotor body, or a different material is disposed in the center portion. Although it is actually configured, as a configuration for maintaining the strength with a small amount of material, a hollow portion 1y or a spoke 1z may be provided in the central portion of the rotor body. FIG. 15 is a plan sectional view showing a structure in which a central portion of the rotor body is hollowed by the cavity 1y, and FIG. 16 is a structure in which spokes 1z are provided. With such a structure, the rotor can be further reduced in weight, and a motor with high efficiency and high power can be obtained.

[0066]

As described above, according to the present invention, the rotor main body is formed by using a low magnetic permeability material, and the magnetic flux is hardly distributed in the rotor main body. And the material of the rotor body can be selected so as to reduce the weight of the rotor, and the effect of reducing the weight of the rotor is achieved. The present invention is applicable to both inner and outer rotors.

Since the permanent magnet is arranged on the outer periphery of the rotor body so as not to generate a leakage magnetic flux to form a magnetic field structure, the rotor can be reduced in weight and a conventional rotor using a high magnetic permeability material is used. To obtain the same magnetic flux density as
The effect of obtaining a motor with improved efficiency was obtained.

Since a resin is used as the low magnetic permeability material, the weight of the rotor can be reduced. If, for example, polybutylene terephthalate is used as the resin, a rotor having excellent mechanical strength, electrical insulation, and workability such as cutting can be formed, and furthermore, the magnetic flux is hardly distributed in the rotor body, and the rotor is lightweight. Therefore, a motor with improved efficiency can be obtained.

Since the 2M permanent magnets are arranged so that the magnetic field lines formed by the 2M permanent magnets do not distribute in the material, a magnetic field having a high magnetic flux density can be obtained, and There is almost no magnetic field line short-circuit.

Of the 2M permanent magnets, M first magnets
The permanent magnets are disposed on the rotor body such that a predetermined interval is maintained, and the directions of the polarities of the permanent magnets are opposite to each other in a radially outward direction and a radially inward direction, respectively. A second permanent magnet is provided between each two adjacent first permanent magnets, and the polarity of the second permanent magnet is set along the circumferential direction to the polarity of the magnetic pole outside the first permanent magnet. Since it is arranged so as to have the same polarity as the above, a magnetic field having a high magnetic flux density is obtained.

In the motor according to the present invention, for example, the shape of the first permanent magnet can be rectangular and the shape of the second permanent magnet 3 can be trapezoidal. The arrangement provides a magnetic field with a high magnetic flux density.

In the motor according to the present invention, since the first permanent magnet and the second permanent magnet are mounted on the surface of the rotor body, a rotor yoke is not required, and the magnetic flux generated by the permanent magnet is not changed. It can contribute to rotation.

In the motor according to the present invention,
The first permanent magnet and the second permanent magnet can be attached to a concave portion provided on a surface of the rotor body,
Alternatively, since the permanent magnet can be buried in the rotor, the permanent magnet does not fall off due to the rotation.

In the motor according to the present invention, a high magnetic permeability material can be used for the portion of the rotor body on the rotor shaft side, so that the mechanical strength of the rotor body can be enhanced.

In the motor according to the present invention, a penetrating hollow portion can be provided in the rotor body.
Alternatively, since the rotor body can be formed in a shape having spokes, the rotor can be further reduced in weight and efficiency can be improved.

The method for manufacturing a motor according to the present invention
A method for manufacturing a motor, comprising: an inner (or outer) rotor having a plurality of permanent magnets attached thereto; and a stator, wherein a low-permeability material is used as a material of the rotor body. Forming, forming the rotor body, attaching the 2M permanent magnets to the rotor body, and assembling a stator and a rotor body to which 2M permanent magnets are attached. It is characterized by. With such characteristics, a motor with improved efficiency can be formed using a material having low magnetic permeability.

In the method for manufacturing a motor according to the present invention, the rotor main body and the 2M permanent magnets can be formed by an integral molding method. Therefore, there is no need for an assembling step of attaching the permanent magnets to the rotor. It has the effect of being cheap.

In the method of manufacturing a motor according to the present invention, the rotor body is formed by an inexpensive mold because a recess is provided at a predetermined position of the rotor body and the 2M permanent magnets are attached to each of the recesses. Therefore, the present invention has an effect of reducing the manufacturing cost even for a large variety of small models.

In the method of manufacturing a motor according to the present invention, the 2M permanent magnets are attached to predetermined positions of the rotor body, and the outer peripheral sides of the attached 2M permanent magnets are covered with a ring-shaped member. To form a rotor,
There is no need for a mold or the like, so that the production cost can be reduced even for a large variety of small models.

[Brief description of the drawings]

FIG. 1 is an explanatory plan sectional view showing a structure of an inner rotor type motor according to an embodiment of the present invention.

FIG. 2 is an explanatory plan sectional view showing an arrangement of a configuration including a direction of polarity of a permanent magnet used in the inner rotor type motor according to the embodiment of the present invention;

FIG. 3 is an explanatory plan sectional view showing an example having no rotor yoke shown in FIG. 1;

FIG. 4 is an explanatory plan sectional view showing a structure of an outer rotor type motor according to one embodiment of the present invention.

FIG. 5 is an explanatory plan sectional view showing an arrangement of a configuration including a direction of polarity of a permanent magnet used in the outer rotor type motor according to the embodiment of the present invention;

FIG. 6 is an explanatory plan sectional view showing an example having a rotor yoke of the outer rotor type motor shown in FIG. 4;

FIG. 7 is a schematic plan view schematically showing a magnetic flux distribution in an outer rotor type motor in which only a basic magnet is provided on a rotor body made of a resin material.

FIG. 8 is a schematic plan view schematically showing a magnetic flux distribution in an outer rotor type motor in which only a basic magnet is provided in a rotor main body made of iron.

FIG. 9 is a schematic plan view schematically showing a magnetic flux distribution in an outer rotor type motor in which a basic magnet and an auxiliary magnet are provided on a rotor main body made of a resin material.

FIG. 10 is a schematic plan view schematically showing a magnetic flux distribution in an outer rotor type motor in which a basic magnet and an auxiliary magnet are provided on a rotor main body made of iron.

FIG. 11 is a graph schematically showing a magnetic flux distribution in the outer rotor type motor shown in each of FIGS. 7 to 10;

FIG. 12 is an explanatory perspective view showing a method for manufacturing a rotor in which a permanent magnet is integrally embedded in a synthetic resin according to the present invention.

FIG. 13 is an explanatory perspective view showing a method of manufacturing an assembled rotor provided with a concave portion into which a permanent magnet according to the present invention can be inserted.

FIG. 14 is an explanatory perspective view showing a manufacturing method of obtaining a rotor by attaching a ring-shaped member after attaching a permanent magnet according to the present invention.

FIG. 15 is an explanatory plan sectional view showing a structure in which a central portion of a rotor main body according to the present invention is hollowed by a hollow portion 1y.

FIG. 16 is an explanatory plan sectional view showing a structure in which spokes 1z are provided at a central portion of a rotor main body according to the present invention.

FIG. 17 is an explanatory plan sectional view showing a conventional motor.

FIG. 18 is an explanatory plan sectional view showing a conventional motor.

FIG. 19 is an explanatory plan sectional view showing a conventional motor.

FIG. 20 is an explanatory plan sectional view showing a part of a conventional motor.

FIG. 21 is an explanatory plan sectional view showing a conventional motor.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 ... Rotor, 2 ... 1st permanent magnet, 3 ... 2nd permanent magnet, 4 ... Stator

Claims (17)

[Claims] When M is a positive even number, an inner rotor (1) on which 2M permanent magnets are mounted and a stator (4) are used, and the material of the rotor body (1a) is small. A motor comprising a material having magnetic permeability. 2. The motor according to claim 1, wherein a resin is used as the material. 3. The motor according to claim 2, wherein polybutylene terephthalate is used as the resin. 4. The motor according to claim 1, wherein the 2M permanent magnets are arranged such that the lines of magnetic force formed by the 2M permanent magnets do not distribute in the material. 5. Among the 2M permanent magnets, each of the M first permanent magnets (2) is maintained at a predetermined interval, and the polarities of the first permanent magnets (2) are radially outward and radially outward. The rotor body so that the inward of
(1a), and a second permanent magnet (3) is provided between two adjacent first permanent magnets (2), respectively.
5. The device according to claim 4, wherein the polarity of the second permanent magnet is the same as the polarity of the magnetic pole outside the first permanent magnet along the circumferential direction. motor. 6. The motor according to claim 5, wherein the shape of the first permanent magnet is rectangular, and the shape of the second permanent magnet is trapezoidal. 7. The motor according to claim 6, wherein said first permanent magnet (2) and said second permanent magnet (3) are mounted on a surface of said rotor body (1a). 8. The rotor according to claim 6, wherein said first permanent magnet and said second permanent magnet are mounted in a recess provided in a surface of said rotor body. Motor. 9. The motor according to claim 6, wherein the first permanent magnet (2) and the second permanent magnet (3) are embedded in the rotor (1). 10. The rotor shaft (1) of the rotor body (1a).
2. The motor according to claim 1, wherein a material having a high magnetic permeability is used for a portion on the x) side. 11. The motor according to claim 1, wherein a hollow portion (1y) penetrating through the rotor body (1a) is provided. 12. The rotor body (1a) has spokes (1a).
The motor according to claim 1, wherein the motor is formed in a shape having z). 13. When M is a positive even number, the rotor comprises an outer-type rotor (6) on which 2M permanent magnets are mounted, and a stator (9), and is small as a material of the rotor body (6a). A motor comprising a material having magnetic permeability. 14. When M is a positive even number, the rotor comprises an inner rotor (1) having 2M permanent magnets attached thereto and a stator (4). The rotor body (1a) has a small material. A method for manufacturing a motor using a material having magnetic permeability, comprising: forming the stator (4);
Forming the rotor body (1a);
(1a) mounting the 2M permanent magnets; and assembling the stator (4) and the rotor body (1a) to which the 2M permanent magnets are mounted. 15. The manufacturing method according to claim 14, wherein the rotor main body (1a) and the 2M permanent magnets are formed by an integral molding method. 16. A recess (11) is provided at a predetermined position of the rotor body (1a), and each of the recesses (11) has the 2M portion.
The manufacturing method according to claim 14, wherein the permanent magnets are respectively attached. 17. The 2M permanent magnets are respectively attached to predetermined positions of the rotor body (1a), and the outer peripheral side of the attached 2M permanent magnets is a ring-shaped member (12).
The manufacturing method according to claim 14, wherein the rotor is formed by coating with a coating.