JP5733556B2 - Inner rotor type brushless motor and method for manufacturing the inner rotor type brushless motor - Google Patents

Description

  The present invention relates to an inner rotor type brushless motor applicable to, for example, a small pump and a method for manufacturing the inner rotor type brushless motor.

Conventionally, in this type of invention, a rotor having a permanent magnet, a stator core having a plurality of teeth portions disposed around the rotor in a circumferential direction, and windings wound around the teeth portions, The slot opening is arranged on the inner peripheral side of the stator core (see, for example, Patent Document 1).
According to this prior art, winding of the winding around each tooth portion has to be performed from the inner peripheral side of the stator core, and the slot opening is relatively narrow, so that the winding operation is difficult. It was also difficult to increase the space factor of the line.

Therefore, as another conventional technique, adjacent teeth portions on the inner peripheral side of the stator core are connected, a slot opening portion is provided on the outer peripheral side of the stator core, and a winding is wound using the slot opening portion on the outer peripheral side. Later, there is one in which a cylindrical yoke portion is fitted around the teeth portion (see Patent Document 2).
According to this prior art, winding of the winding around each tooth portion is performed from the outer peripheral side of the stator core, so that the winding work is easy and a relatively wide slot opening can be secured, and the winding is performed. It was easy to increase the space factor of the line. Furthermore, there is an advantage that the cogging torque can be reduced as compared with the former prior art configuration in which the slot opening is provided on the inner peripheral side of the stator core.

  However, according to the latter prior art, since the magnetic path is formed by the adjacent tooth portions and the yoke portion connecting the teeth portions, it is necessary to increase the thickness of the yoke portion to some extent. As a result, there has been a problem that the outer diameter of the motor is increased and the weight is increased. There is also a problem that eddy current is generated in the yoke portion and motor efficiency is lowered.

JP 2007-259513 A JP 2002-142391 A

  The present invention has been made in view of the above-mentioned conventional circumstances, and the problem is that the winding work is easy and the cogging torque can be reduced, and the size and weight can be reduced. An object of the present invention is to provide an inner rotor type brushless motor capable of improving efficiency and a method of manufacturing the inner rotor type brushless motor.

  The technical means for solving the above-described problems are a rotor having a permanent magnet, a stator core having a plurality of teeth portions arranged around the rotor at intervals in the circumferential direction, and wound around each of the tooth portions. In an inner rotor type brushless motor having windings, on the stator inner peripheral side between the adjacent tooth portions, a connecting portion for connecting the two tooth portions is provided, and on the stator outer peripheral side between the tooth portions. A slot opening that communicates the slot space between both teeth and the outer space of the stator is provided, and a spacer that is made of a magnetic material and is independent for each slot opening is mounted in the slot opening. It is characterized by.

  Further, as a mode of improving productivity and forming a good magnetic path, the spacer is formed so that the interval in the rotor circumferential direction becomes narrower toward the inner direction of the stator.

  Moreover, as a preferable aspect for reducing the generation of eddy current, the spacer is made of any of Permalloy PB, Permalloy PC, 3% silicon free-cutting steel, permendur, and Fe-Al magnetic material.

  Further, in order to reduce the generation of eddy current, the spacer is made of a material having a higher specific resistance than the stator core.

  In order to improve the strength, a housing is provided so as to surround the outer periphery of the stator core and the spacer.

  Further, as a preferred mode for reducing the generation of eddy current, the spacer is formed by laminating a plurality of plate-like magnetic bodies in the rotor axial direction while insulating each other.

  As a preferred mode for increasing the strength, the spacer is an integral member extending in the rotor axial direction.

  In addition, in order to improve heat dissipation, unevenness is provided on the outer surface of the spacer.

  Furthermore, in order to improve productivity, increase strength, improve heat dissipation, etc., the concave and convex portions of the outer surface of the spacer are formed so as to be continuous in the rotor circumferential direction, and the outer surface of the spacer is A concave portion continuing to the concave portion is provided, and the spacer holding member is mounted so as to straddle both the concave portions.

  Furthermore, as a preferable manufacturing method of the inner rotor type brushless motor, the spacer is mounted in the slot opening in a step subsequent to the step of winding the winding around the teeth portions.

Since the present invention is configured as described above, the following effects can be obtained.
The connecting part is provided on the inner periphery of the stator between adjacent teeth, and the slot opening is provided on the outer periphery of the stator between both teeth. Torque is relatively small.
In addition, since the spacer is mounted in the slot opening on the outer periphery side of the stator core, the yoke portion and the housing provided around the stator core are made thinner and lighter, or the yoke portion and the housing are omitted. As a result, the brushless motor can be reduced in size and weight.
In addition, a good magnetic path having a low magnetic resistance can be formed by the adjacent teeth portions and the magnetic spacers between the teeth portions, thereby improving the motor efficiency.

It is a front view showing an example of an inner rotor type brushless motor concerning the present invention. It is a perspective view which shows the stator core in the same example. It is a perspective view which shows the spacer in the same example. It is a front view which shows the other example of the inner rotor type brushless motor which concerns on this invention. It is a perspective view which shows the stator core in the same example. It is a perspective view which shows the spacer and spacer holding member in the other example. It is principal part sectional drawing in the other example, and the rotor and the coil are abbreviate | omitted. It is a table | surface which shows the material example in the inner rotor type brushless motor which concerns on this invention.

Hereinafter, a first embodiment according to the present invention will be described with reference to the drawings.
As shown in FIG. 1, the brushless motor 1 is an inner rotor type brushless motor including a rotor 10 having permanent magnets 12 and a stator 20 provided around the rotor 10.

  The rotor 10 fixes a permanent magnet 12 (specifically, a cylindrical magnet) to the outer peripheral side of a columnar rotor core 11 made of a magnetic material, and fixes the central portion of the rotor core 11 to a shaft portion 13. The portion 13 is rotatably supported with respect to the stator core 21 via a bearing or the like (not shown).

  In addition, the stator 20 includes a stator core 21 having a plurality of teeth portions 21a arranged around the rotor 10 at intervals in the circumferential direction, a winding 22 wound around the teeth portions 21a, and adjacent teeth portions 21a and 21a. A spacer 23 mounted in the slot opening 20a therebetween, and a cylindrical housing 24 surrounding the stator core 21 and the outer periphery of the spacer 23 are provided.

As shown in FIG. 2, the stator core 21 is formed by laminating a plurality of thin plate-like magnetic bodies and laminating them in the rotor axial direction and arranged at intervals in the rotor circumferential direction (illustrated example). 6) teeth portions 21a, connecting portions 21b and 21b extending from the end portion on the stator inner peripheral side of each teeth portion 21a to both sides in the circumferential direction and connected to adjacent teeth portions 21a, Each tooth portion 21a has an overhang portion 21c extending from the end portion on the outer peripheral side of the stator to both sides in the circumferential direction.
And this stator core 21 makes slot space S for accommodating the coil | winding 22 between adjacent teeth parts 21a and 21a, and between adjacent teeth parts 21a and 21a (in detail, adjacent overhang | projection parts 21c, 21c) has a slot opening 20a that communicates the slot space S with the outer space of the stator.

The material of the stator core 21 can be selected from well-known thin plate-like magnetic bodies, and a preferred embodiment is a silicon steel plate shown in the table of FIG. The above table exemplifies two types of silicon steel plates, and these are applicable to different manufacturers, although the saturation magnetic flux density is slightly different.
A large number of the silicon steel plates are laminated in the rotor axial direction, and the steel plates are joined together by a joining means such as adhesion or doweling (fitting by unevenness).

  Further, according to the example shown in FIG. 1, the tooth portion 21 a in the stator core 21 is formed in a cross-sectional columnar shape in which both side surfaces on the slot space S side are arranged in parallel.

The connecting portion 21b extends in the circumferential direction from the end portion of the teeth portion 21a on the inner peripheral side of the stator, and is formed so as to gradually become thinner in the extending direction.
A thin portion 21b1 that is locally thin is provided at a joint between the adjacent connecting portions 21b and 21b.
The thin-walled portion 21b1 forms a concave groove on the inner peripheral portion of the stator at the connection location, and forms a convex strip on the corresponding outer peripheral portion of the stator, and a thickness between the inner surface of the concave groove and the outer surface of the convex strip. Is made narrower than other portions in the connecting portion 21b.
And according to the connection part 21b of the said structure, a cogging torque can be reduced effectively.

Further, the overhanging portion 21c extends in the circumferential direction from the end portion of the teeth portion 21a on the outer periphery side of the stator, and according to the illustrated example, the inner surface is formed in a plane substantially perpendicular to the side surface of the teeth portion 21a. The outer surface is formed into a curved surface having an arcuate cross section. And between the front-end | tip parts of adjacent overhang | projection parts 21c and 21c is made into the slot opening part 20a for mounting the spacer 23 mentioned later.
The slot openings 20a are formed so that the interval in the circumferential direction of the rotor gradually decreases toward the stator inward direction (in other words, the direction toward the rotor axis).

And the insulating film is formed in the outer surface of the stator core 21 of the said structure by electrodeposition coating. The insulating film may be formed at least on the exposed surfaces at both ends in the axial direction of the stator core 21 and on the surface located in the slot space S. In this embodiment, the film forming operation is simplified to improve workability. In order to improve, an insulating film is formed on the entire outer surface including the outer peripheral surface of the stator core 21 and the inner peripheral surface of the stator core 21.
The means for forming the insulating film on the outer surface of the stator core 21 is not limited to the electrodeposition coating, and may be other coating means such as powder coating. Furthermore, it is also possible to replace the insulating film by painting as described above and to attach an insulator to the outer surface of the stator core 21.

  As shown in FIG. 1, the space surrounded by the tooth portion 21a, the connecting portion 21b, and the overhanging portion 21c (that is, one half of the slot space S) is gradually increased in cross-sectional area toward the adjacent tooth portions 21a. It becomes an expanded space. According to the space having such a shape, the winding workability of the winding 22 can be improved, and the space factor of the wound winding 22 can be made relatively large. Can be improved.

  The winding 22 is wound around each tooth portion 21a so that a flyer of a winding machine is inserted into the slot opening portion 20a from the outer peripheral side of the stator. And after winding 22 is wound around each teeth part 21a, spacer 23 is installed in each slot opening 20a.

The spacer 23 is made of a magnetic material and is an independent member for each slot opening 20a (see FIGS. 1 and 3). That is, each spacer 23 is a separate member with respect to the stator core 21 and the housing 24, and is also a separate member with respect to other adjacent spacers 23.
The spacer 23 is fitted into the slot opening 20a in the rotor axial direction so as to close the slot opening 20a.
According to the illustrated example, the inner surface of the spacer 23 (the surface on the inner peripheral side of the stator) is formed in a planar shape substantially parallel to the connecting portion 21b. Further, the outer surface of the spacer 23 (the surface on the outer periphery side of the stator) is formed into a curved surface having an arcuate cross section that is flush with the outer surface of the overhang portion 21c.
The spacer 23 is formed in a cross-sectional wedge shape in which the interval in the rotor circumferential direction becomes narrower toward the inside of the stator. When the spacer 23 is attached to the slot opening 20a, a gap is almost formed between the spacer 23 and the inner surface of the slot opening 20a. Fit so that there is no.

The material of the spacer 23 is different from the material of the stator core 21.
Specific examples thereof include five types of magnetic materials shown in the table of FIG. 8, that is, permalloy PB, permalloy PC, 3% silicon free-cutting steel, permendur, and Fe—Al magnetic material (or Fe—Al magnetic steel plate). Is mentioned. Fe means iron, and Al means aluminum. The symbol (PB, PC) is a symbol defined by JISC2531.
The spacer 23 is preferably made of a material having a higher specific resistance (electric resistance) than the stator core 21 from the viewpoint of reducing generation of eddy current. Therefore, among the specific examples, it is particularly preferable that the material is any one of Permalloy PB, Permalloy PC, 3% silicon free-cutting steel, and Fe—Al magnetic material.

The material of the spacer 23 is preferably a material having a relatively high saturation magnetic flux density (or a material having a relatively small magnetic resistance) from the viewpoint of forming a good magnetic path M, and in particular, equivalent to the stator core 21. Or it is preferable that it is a material which has saturation magnetic flux density close | similar to equivalent.
Therefore, from this viewpoint, in the above specific examples, permalloy PB, 3% silicon free-cutting steel, permendur, and Fe-Al magnetic material are preferable, and permendur is particularly preferable.

  Further, the material of the spacer 23 is preferably a material having a specific resistance higher than that of the stator core 21 and a relatively high saturation magnetic flux density in order to reduce eddy current loss and form a good magnetic path M. From the viewpoint, among the above specific examples, permalloy PB, 3% silicon free-cutting steel, and Fe—Al magnetic material are particularly preferable.

According to the example shown in FIG. 3, the spacer 23 is formed by arranging a large number of plate-like members made of the above-described materials in the axial direction of the rotor and laminating them while insulating them from each other (interlayer). It is joined by joining means such as dowel stops (fitting by unevenness).
As described above, in the aspect in which the spacer 23 is configured from the laminated plate, the generation of eddy currents generated in the spacer 23 is reduced as compared with the aspect in which the spacer 23 is configured as an integral member that extends in the rotor axial direction. be able to.

The spacer 23 having the above-described configuration is press-fitted in a wedge shape in the slot opening 20a in a step after the step of winding the winding 22 around each tooth portion 21a.
If necessary, an adhesive may be interposed between the inner surface of the slot opening 20a and the spacer 23, or a structure in which the inner surface of the stator 20 and the spacer 23 are fitted by unevenness to increase the strength. It may be.

As another example of the spacer 23, the spacer 23 may be an integral member (that is, a single block member that does not use a laminated plate) extending in the rotor axial direction. According to this aspect, since the integrated spacer 23 is fitted to the stator core 21 that is a laminate, it is possible to prevent the steel plates constituting the stator core 21 from being separated.
However, in the other example of this spacer 23, since there is a possibility that eddy current may increase as compared with the aspect configured from the laminated plate as described above, it is preferable to use the above material having higher specific resistance than the stator core 21. Configure.

  The housing 24 is a substantially cylindrical member that is mounted on the outer peripheral surfaces of the stator core 21 and the spacer 23 so as to be in contact with the outer peripheral surfaces of the stator core 21 and the spacer 23 (see FIG. 1). In addition to preventing the stator core 21 from being detached or displaced, the spacers 23 and the steel plates constituting the stator core 21 are prevented from separating, thereby increasing the strength of the stator 20.

  The housing 24 can be made of a relatively thin material. Specific examples of the material include Al (aluminum), resin (including natural resin and synthetic resin) as shown in the table of FIG. ), SPCC (JISG 3141: cold rolled steel sheet for general use), and SPCE (JISG 3141: cold rolled steel sheet for deep drawing). In particular, when the housing 24 is made of a resin material, the generation of eddy currents in the housing 24 can be prevented and the weight can be reduced.

Next, the characteristic effect of the brushless motor 1 having the above-described configuration will be described in detail.
First, in the manufacturing stage, a winding can be wound around each tooth portion 21a from the outer periphery of the stator, and the dimension of the slot opening 20a in the circumferential direction of the rotor gradually narrows toward the inside of the stator. Therefore, it is easy to insert the flyer of the winding machine into the slot space S, and consequently, the winding workability of the winding can be improved.
Further, when the spacer 23 is press-fitted into the slot opening 20a, the spacer 23 is wedge-shaped in cross section, so that the press-fitting operation can be easily performed and the spacer 23 after being mounted is held so as not to easily come off. be able to.

Further, when the winding 22 is energized after the completion of the brushless motor 1, the adjacent teeth 21 a and the overhanging portion 21 c and the spacer 23 sandwiched between them are used as shown in FIG. An annular magnetic path M indicated by a chain line can be formed. Therefore, for example, a good magnetic path M having a small magnetic resistance can be obtained as compared with a configuration in which the spacer 23 is omitted or a structure in which a space or a groove is provided between adjacent overhang portions. As a result, the motor of the brushless motor 1 can be obtained. Efficiency can be improved.
In particular, in the present embodiment, generation of eddy currents in the spacer 23 can be reduced and the motor efficiency can be effectively improved by devising the laminated structure and material of the spacer 23 described above.

Further, as described above, since the magnetic path M is formed by the teeth portion 21a, the overhang portion 21c, and the spacer 23, it is not necessary to make the housing 24 thick to form the magnetic path. Thus, the brushless motor 1 can be reduced in size and weight.
If the strength is sufficient, the housing 24 can be omitted from the brushless motor 1 having the above-described configuration, and the size and weight can be further reduced.

Next, the brushless motor 2 which is 2nd Embodiment based on this invention is demonstrated with reference to FIGS.
The brushless motor 2 has a partly changed configuration with respect to the brushless motor 1 described above, and the same reference numerals are given to portions common to the brushless motor 1 to omit redundant detailed description.

The brushless motor 2 has a configuration in which the stator 20 is replaced with a stator 20 ′ with respect to the brushless motor 1 (see FIG. 4).
The stator 20 ′ includes a stator core 21 ′, a winding 22, a spacer 23 ′, and a spacer holding member 30 (see FIGS. 6 and 7).

Similarly to the brushless motor 1, the stator core 21 ′ is formed by laminating a plurality of thin plate-like magnetic bodies in the rotor axial direction, and includes a teeth portion 21a ′, a connecting portion 21b ′, a thin portion 21b1 ′, an overhang portion 21c ′, It has a slot opening 20a ′, a slot space S, and the like.
Further, the stator core 21 'is provided with a plurality of concave portions 21c1' continuous in the circumferential direction of the rotor on the outer circumferential surface thereof (specifically, the outer surface of each overhanging portion 21c ') with an interval in the rotor axial direction (see FIG. 5).

The spacer 23 ′ has an appearance substantially similar to that of the spacer 23 described above, and has a plurality of recesses 23 a ′ arranged on the outer surface thereof in the rotor axial direction at the same pitch as the plurality of recesses 21 c 1 ′. Each recess 23a ′ is disposed so as to be continuous with the recess 21c1 ′ in the circumferential direction of the rotor.
The spacer 23 ′ in the illustrated example is configured as an integral member extending in the rotor axial direction from the viewpoint of improving the strength (see FIG. 6). The spacer 23 ′ is preferably made of a material having a higher specific resistance than the stator core 21 ′ in order to reduce the generation of eddy currents.

The spacer holding member 30 is a C-shaped retaining ring member shown in FIGS. 6 and 7, and is formed of an elastic metal material such as a spring material so as to be elastically deformed in the diameter increasing direction.
The cross-sectional shape of the spacer holding member 30 is set so that it fits into the recess 21c1 ′ and the recess 23a ′ and does not protrude outside from these recesses.
The spacer holding member 30 is provided corresponding to at least one of the plurality of recesses 21c1 ′ and recesses 23a ′ arranged substantially parallel to the rotor axial direction. The spacer holding member 30 is annularly fitted into the recesses 21c1 ′ and the recesses 23a ′ so as to straddle between the recesses 21c1 ′ and the recesses 23a ′ adjacent in the circumferential direction (see FIG. 7).

Next, the characteristic effect of the brushless motor 2 according to the second embodiment will be described.
First, in the manufacturing stage, the winding 22 is mounted on the stator core 21 ′, and after the spacer 23 ′ is mounted on the slot opening 20a ′ of the stator core 21 ′, the spacer holding member 30 is elastically expanded in diameter. Thus, it is mounted on at least one of the plurality of recesses 21c1 ′ and recesses 23a ′ arranged substantially parallel to the rotor axial direction.
Therefore, the spacer holding member 30 can prevent the spacer 23 ′ from being displaced or removed in the radial direction or the thrust direction (rotor axial direction) with respect to the stator core 21 ′.
Note that the number of spacer holding members 30 may be single or plural, and may be a minimum number within a range in which the mounting strength of the spacer 23 ′ can be sufficiently secured.

Further, when the winding 22 is energized, like the brushless motor 1 described above, the adjacent tooth portion 21a ′ and the overhang portion 21c ′ and the spacer 23 ′ sandwiched between them, A good magnetic path can be formed.
At this time, since a plurality of recesses and recesses 21c1 ′ and recesses 23a ′ are formed on the outer periphery of the stator core 21 ′ and the spacer 23 ′, the recesses 21c1 ′ and the recesses 23a ′ cause heat in the stator core 21 ′ and the spacer 23 ′ to be generated. It can dissipate heat.

  In addition, according to the said embodiment, although the spacer holding member 30 was formed in the C-shaped retaining ring shape as a preferable example, this spacer holding member 30 is fitted so that it may straddle the recessed part 21c1 'and the recessed part 23a'. As long as it is, it is not limited to the said shape, For example, it can also be set as a circular-arc-shaped member.

  In addition, according to the example of the above embodiment, the overhang portion 21c (or 21c ′) is provided from the viewpoint of forming a good magnetic path. As another example, the overhang portion 21c (or 21c ′) is illustrated. It is also possible to improve the winding workability of the winding wire 22 around the tooth portion 21a (or 21a ′) by shortening or omitting it from the above.

  Further, according to an example of the above-described embodiment, the material of the spacer 23 is different from the material of the stator core 21 as a preferable aspect. However, as another example, the spacer 23 and the stator core 21 can be made of the same material. It is.

  Further, according to the second embodiment, the housing 24 is omitted in order to improve heat dissipation and reduce the size and weight. However, as another example, from the viewpoint of increasing the strength. It is also possible to adopt a mode in which the housing 24 is mounted around the brushless motor 2 having the above configuration.

  Further, according to the second embodiment, the spacer 23 ′ is an integral member extending in the rotor axial direction from the viewpoint of improving the strength. However, as another example, particularly, the generation of eddy current is reduced. The spacer 23 'can be a member made of a laminated plate.

In the second embodiment, as a particularly preferable aspect for improving heat dissipation, irregularities are provided on the outer surfaces of both the stator core 21 'and the spacer 23'. As another example, the second embodiment described above is used. It is also possible to omit the recess 21c1 ′ from the stator core 21 ′ and to have an unevenness due to the recess 23a ′ only on the outer surface of the spacer 23 ′.
Further, in the first embodiment, the outer surface of the spacer 23 made of a laminate is not provided with irregularities. However, as another example, in the case where the housing 24 is omitted in order to reduce the size and weight, etc. Alternatively, the heat dissipation may be improved by providing irregularities on the outer surface of the spacer 23 made of a laminate.

DESCRIPTION OF SYMBOLS 1, 2: Brushless motor 10: Rotor 11: Rotor core 12: Permanent magnet 20, 20 ': Stator 20a, 20a': Slot opening part 21, 21 ': Stator core 21a, 21a': Teeth part 21b, 21b ': Connection part 21c, 21c ′: Overhang portion 21c1 ′: Recess 22: Winding 23, 23 ′: Spacer 23a ′: Recess 30: Spacer holding member S: Slot space M: Magnetic path

Claims (8)

In an inner rotor type brushless motor comprising: a rotor having a permanent magnet; a stator core having a plurality of teeth portions disposed around the rotor in a circumferential direction; and a winding wound around each of the teeth portions. ,
A connecting portion for connecting the two teeth portions is provided on the stator inner peripheral side between the adjacent tooth portions, and a slot space between the teeth portions and a space on the stator outer periphery are provided on the stator outer peripheral side between the two tooth portions. Slot opening to communicate with the
A spacer, which is made of a magnetic material and is independent for each slot opening, is mounted in the slot opening ,
The outer surface of the spacer is provided with irregularities,
The concave and convex portions on the outer surface of the spacer are formed so as to be continuous in the circumferential direction of the rotor, and the outer surface of the stator core is provided with a concave portion that is continuous with the concave portion on the outer surface of the spacer, and a spacer holding member is provided so as to straddle both the concave portions. An inner rotor type brushless motor characterized by being mounted .   The inner rotor type brushless motor according to claim 1, wherein the spacer is formed so that an interval in a circumferential direction of the rotor becomes narrower toward an inward direction of the stator.   3. The inner rotor type brushless motor according to claim 1, wherein the spacer is made of any one of Permalloy PB, Permalloy PC, 3% silicon free cutting steel, permendur, and Fe—Al magnetic material. .   4. The inner rotor type brushless motor according to claim 1, wherein the spacer is made of a material having a higher specific resistance than the stator core. 5.   The inner rotor type brushless motor according to any one of claims 1 to 4, wherein a housing is provided so as to surround the outer periphery of the stator core and the spacer.   6. The inner rotor type brushless motor according to claim 1, wherein the spacer is formed by laminating a plurality of plate-like magnetic bodies in the rotor axial direction while insulating each other.   6. The inner rotor type brushless motor according to claim 1, wherein the spacer is an integral member extending in the rotor axial direction. 8. The inner rotor type brushless according to claim 1, wherein the spacer is mounted in the slot opening in a step subsequent to a step of winding the winding around each of the teeth portions. A method for manufacturing a motor .

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