JP6877658B2 - Synchronous motor - Google Patents

Description

The present invention relates to a synchronous motor in which resin is filled between the teeth of the stator.

Motors include synchronous motors that include a stator with windings wound around a tooth and a rotor with permanent magnets. In a synchronous motor, noise is generated by vibrating the stator due to electromagnetic force generated by mutual interference between the magnetic flux of the stator and the magnetic flux of the rotor.

Patent Document 1 discloses an electric motor in which vibration of the stator is suppressed by providing a support portion of a non-magnetic material that connects the tips of the teeth to each other, and noise is suppressed.

Japanese Unexamined Patent Publication No. 2002-112473

The loudness of noise is greatly affected by the resonance of the structure. In noise caused by electromagnetic force, the resonance of the stator is often a problem. Stator resonance includes a unique mode in which the annular stator transforms into an ellipse or polygon.

Further, the electromagnetic force generated by the synchronous motor is a spatial harmonic having a spatial distribution in the circumferential direction of the inner diameter of the stator formed in a ring shape. The order of the harmonics is determined by the number of poles of the rotor and the number of slots, which is the space between the teeth. If the electromagnetic force generated by the synchronous motor is a second harmonic, a force that deforms the stator into an elliptical shape is generated. If the electromagnetic force generated by the synchronous motor is the 4th harmonic, a force that deforms the stator into a quadrangle is generated. The shape in which the electromagnetic force tries to deform the stator is referred to as the spatial mode of the electromagnetic force. That is, if the electromagnetic force is a second harmonic, the spatial mode of the electromagnetic force is elliptical. If the electromagnetic force is the 4th harmonic, the spatial mode of the electromagnetic force is quadrangular.

The frequencies of the intrinsic mode due to the resonance of the stator and the spatial mode of electromagnetic force differ depending on the order of the modes. When the intrinsic mode and the spatial mode of electromagnetic force match and the frequencies match, they resonate with each other and remarkable vibration and noise are generated. The noise generated for this reason is high frequency noise caused by a multiple component of the motor drive current and a PWM harmonic component. High frequency noise is easily perceived as a very jarring sound.

Just by connecting the tips of the teeth to each other as in the motor disclosed in Patent Document 1, the vibration and noise generated when the intrinsic mode and the spatial mode of the electromagnetic force match and the frequencies match are sufficient. It cannot be suppressed. Further, it cannot be sufficiently suppressed that the frequency of the electromagnetic excitation force and the resonance frequency in the natural mode of the stator coincide with each other to generate noise.

The present invention has been made in view of the above, and generates noise due to the coincidence between the intrinsic mode and the spatial mode of the electromagnetic force and the coincidence between the resonance frequency of the stator and the frequency of the electromagnetic excitation force. The purpose is to obtain a synchronous motor that can be suppressed.

In order to solve the above-mentioned problems and achieve the object, the present invention has a cylindrical core back, a plurality of teeth formed radially protruding from the core back and arranged side by side in the circumferential direction, and a slot cell covering the teeth. A stator having a winding portion formed by winding a winding around a tooth via a slot cell, and a molded portion formed by filling resin between adjacent teeth. The teeth have an extension portion that extends radially from the core back and an expansion portion that extends in the circumferential direction from the tip of the extension portion, and the slot cell has a surface and an extension portion that face the radial inward direction of the core back. It has a first cell portion that covers the outer peripheral surface of the above, and a second cell portion that covers the surface of the enlarged portion that faces outward in the radial direction. The peripheral end of the second cell portion coincides with the circumferential end of the enlarged portion, or the enlarged portions of the adjacent teeth cover at least a part of the opposite surfaces, and the mold portion is formed. A gap is formed between the enlarged portions of at least one adjacent tooth.

According to the present invention, it is possible to obtain a synchronous motor capable of suppressing the generation of noise caused by the matching between the intrinsic mode and the spatial mode of the electromagnetic force and the matching between the resonance frequency of the stator and the frequency of the electromagnetic excitation force. It has the effect of being able to do it.

Sectional drawing which shows the synchronous motor which concerns on Embodiment 1 of this invention. Perspective view of the stator according to the first embodiment It is a perspective view of the stator in Embodiment 1, and is the figure which shows the state which omitted the mold part. Enlarged partial view of a part of the teeth portion in the first embodiment Enlarged partial enlarged cross-sectional view of a part of the teeth portion in the first embodiment It is sectional drawing of the stator in Embodiment 1, and is the figure for demonstrating the position of the 2nd mold part. The figure which shows an example of the relationship between the frequency of the electromagnetic excitation force and the resonance frequency of a stator in the synchronous motor which concerns on Embodiment 1. The figure which shows the frequency Δf in which the response magnification becomes -3dB of the apex on both sides of a resonance peak when a resonance frequency is f0 and a mode attenuation ratio is ζ. The figure which shows the mold used for manufacturing the stator in Embodiment 1. Enlarged partial enlarged cross-sectional view of a part of the teeth portion of the stator provided in the synchronous motor according to the second embodiment. The figure which shows the modification of the slot cell

Hereinafter, the synchronous motor according to the embodiment of the present invention will be described in detail with reference to the drawings. The present invention is not limited to this embodiment.

Embodiment 1.
FIG. 1 is a cross-sectional view showing a synchronous motor according to the first embodiment of the present invention. FIG. 2 is a perspective view of the stator according to the first embodiment. FIG. 3 is a perspective view of the stator according to the first embodiment, showing a state in which the mold portion is omitted. The synchronous motor 20 includes a rotor 11 and a stator 12.

The rotor 11 includes a rotor core 5 and a permanent magnet 6. The rotor core 5 is formed by laminating a plurality of electromagnetic steel sheets punched into a circular shape or an annular shape. Electrical steel sheets are magnetic materials. The shape of the rotor core 5 is a cylindrical shape or a cylindrical shape. The permanent magnet 6 is attached to the outer peripheral surface of the rotor core 5. In the first embodiment, ten permanent magnets 6 are attached to the outer peripheral surface of the rotor core 5. The ten permanent magnets 6 are arranged at equal intervals in the circumferential direction, and the number of poles of the rotor 11 is 10. The permanent magnet 6 may be embedded inside the rotor core 5. Permanent magnets 6 may be attached to the rotating shaft without using the rotor core 5.

The stator 12 includes a stator core 13. The stator core 13 is formed by laminating a plurality of electromagnetic steel sheets. The stator core 13 has a cylindrical core back 1 and a plurality of teeth 2 protruding in the radial direction from the inner peripheral surface of the core back 1. In the present specification, the terms radial direction and circumferential direction mean the radial direction and circumferential direction of the cylindrical core back 1. Further, in the present specification, the term "axial direction" means a direction along the central axis of the cylindrical core back 1. The plurality of teeth 2 are provided side by side at equal intervals in the circumferential direction. In the first embodiment, 12 teeth 2 are provided. The angle θ1 between adjacent teeth 2 about the central axis C of the core back 1 is 30 degrees. The stator core 13 surrounds the rotor 11. A gap is provided between the stator core 13 and the rotor 11. The teeth 2 has an extending portion 22 extending radially inward from the core back 1 and an expanding portion 21 extending in the circumferential direction from the tip of the extending portion 22.

FIG. 4 is a partially enlarged view of a part of the teeth portion in the first embodiment. FIG. 5 is a partially enlarged cross-sectional view of a part of the teeth portion according to the first embodiment. The stator 12 includes a slot cell 3 that covers the periphery of the teeth 2. The slot cell 3 is, for example, a resin molded product. The slot cell 3 includes a first cell portion 31 that covers the radially inward surface of the core back 1 and the outer peripheral surface of the extension portion 22, and a second cell portion 23 that covers the radially outward facing surface of the enlarged portion 21. And have. The circumferential end of the second cell portion 32 coincides with the circumferential end of the enlarged portion 21. The stator 12 includes a winding portion 4. The winding portion 4 is formed by winding a winding around the tooth 2 from above the resin molded product. The winding is intensively wound around the teeth 2. The winding has ends at both ends in the stacking direction of the electromagnetic steel sheets constituting the stator core 13. The slot cell 3 provides insulation between the winding portion 4 and the stator core 13.

The stator 12 includes a mold portion 7. The mold portion 7 is formed of resin filled in the slot 14 which is a space between the teeth 2. The mold portion 7 improves the rigidity of the stator 12 and improves heat dissipation. The mold portion 7 improves the insulating property between the winding portion 4 and the stator core 13. As shown in FIG. 2, in the mold portion 7, in addition to the portion filled inside the slot 14, there is also a portion that covers the end portions of the windings provided at both ends of the electromagnetic steel sheet constituting the stator core 13 in the stacking direction. Have.

As shown in FIG. 5, the mold portion 7 has a first mold portion 7a filled in the slot 14 and a second mold portion 7b filled in the slot 14.

The first mold portion 7a is joined to the surfaces where the enlarged portions 21 of the adjacent teeth 2 face each other. Since the surfaces of the teeth 2 facing each other are not covered by the slot cells 3, the adjacent teeth 2 are joined by the first mold portion 7a. In the slot 14 filled with the first mold portion 7a, the slot cells 3 arranged on both sides thereof, the winding portions 4 and the teeth 2 are joined by the first mold portion 7a. The rigidity of the stator 12 is improved by joining the slot cells 3 to each other, the winding portions 4 to each other, and the teeth 2 to each other by the first mold portion 7a.

The second mold portion 7b is not joined to the surfaces where the enlarged portions 21 of the adjacent teeth 2 face each other. That is, the second mold portion 7b exposes the surfaces on which the enlarged portions 21 of the adjacent teeth 2 face each other. In the slot 14 filled with the second mold portion 7b, the slot cells 3 arranged on both sides thereof and the winding portions 4 are joined by the second mold portion 7b. By joining the slot cells 3 to each other and the winding portions 4 to each other by the second mold portion 7b, the rigidity of the stator 12 can be improved.

However, since the second mold portion 7b is not joined to the surface of the adjacent teeth 2 where the enlarged portions 21 face each other, the teeth 2 are second to each other in the slot 14 filled with the second mold portion 7b. Not joined by the mold portion 7b of. Therefore, the rigidity of the portion filled with the second mold portion 7b is lower than that of the portion filled with the first mold portion 7a. In the slot 14 filled with the second mold portion 7b, the entire region between the enlarged portions 21 of the adjacent teeth 2 is a gap.

The synchronous motor 20 according to the first embodiment is a 10-pole 12-slot motor having a configuration in which the number of poles of the rotor 11 is 10 and the number of slots is 12. FIG. 6 is a cross-sectional view of the stator according to the first embodiment, and is a diagram for explaining the position of the second mold portion. In FIG. 6, hatching is omitted. The second mold portion 7b is provided in a plurality of slots 14. As shown in FIG. 6, the second mold portions 7b are provided at three positions, and the angle θ2 between the second mold portions 7b with respect to the central axis C of the core back 1 is 120 degrees. As shown in FIG. 6, the shape having the apex between the enlarged portions 21 of the teeth 2 provided on both sides of the second mold portion 7b is a triangle. By keeping the angle θ2 constant, the shape having the apex between the enlarged portions 21 of the teeth 2 provided on both sides of the second mold portion 7b can be made into a regular polygon.

In the 10-pole 12-slot motor, the spatial mode of the electromagnetic force in the stator 12 is dominated by the annular elliptical mode and the annular square mode.

In the synchronous motor 20, the second mold portion 7b, which has a lower rigidity than the first mold portion 7a portion, is provided at an angle θ2 of 120 degrees. That is, the second mold portion 7b portion is more easily deformed than the first mold portion 7a portion, and when the second mold portion 7b portion at three locations is deformed, the annular stator 12 is deformed to approach a triangular shape. do. That is, in the stator 12 in the first embodiment, the ring-triangular mode is dominant as the eigenmode.

Therefore, it becomes difficult to match the spatial mode of electromagnetic force in which the annulus ellipse mode and the annulus square mode are dominant and the eigenmode in which the annulus triangle mode is dominant. As a result, it is possible to suppress the generation of remarkable vibration and noise due to the matching between the spatial mode and the natural mode of the electromagnetic force.

If the number of slots 14 is a multiple of 3 of 6 or more and the number of poles of the rotor 11 is not a multiple of 3, the second mold portion 7b is provided so that θ2 is 120 degrees. , It is possible to obtain the effect of suppressing the generation of noise by preventing the coincidence between the spatial mode of the electromagnetic force and the intrinsic mode. Further, even if the above conditions are not met, the arrangement of the second mold portion 7b is determined so that the unique mode is different from the shape of the space mode of the electromagnetic force, so that the space mode of the electromagnetic force is unique. It is possible to obtain the effect of suppressing the generation of noise by preventing the matching with the mode. That is, by changing the arrangement of the first mold portion 7a and the second mold portion 7b according to the spatial mode of the electromagnetic force, the coincidence between the spatial mode of the electromagnetic force and the intrinsic mode is prevented and the generation of noise is suppressed. It becomes possible.

Further, not only a synchronous motor using a stator having a split core in which the core back is divided in the circumferential direction, but also a synchronous motor using a stator having an integral core in which the core back is not divided in the circumferential direction. However, noise can be suppressed by providing the second mold portion.

Inside the slot 14, the tip portion of the teeth 2 is the only portion where the teeth 2 and the mold portion 7 can be directly connected without passing through the slot cell 3, and is a portion where the teeth 2 can be firmly connected to each other. Further, since the tip portion of the teeth 2 is located on the innermost circumference of the annular-shaped stator 12, the thickness of the annular shape in the radial direction changes depending on the presence or absence of the mold portion 7. That is, in the portion where the first mold portion 7a is provided, the thickness of the annular shape in the radial direction increases in the radial direction. On the other hand, in the portion where the second mold portion 7b is provided, the radial thickness of the ring shape becomes smaller in the radial direction. Specifically, in the portion where the first mold portion 7a is provided, the thickness obtained by adding the core back 1 and the teeth 2 becomes the thickness of the ring shape, and in the portion where the second mold portion 7b is provided. , The thickness of only the core back 1 becomes the thickness of the ring shape. Therefore, the presence or absence of the mold portion 7 at the tip portion of the teeth 2 is a factor that has a great influence on the rigidity of the portion. Therefore, by appropriately arranging the mold portion 7 on the tip portion of the teeth 2, the dominant unique mode can be controlled. Therefore, it becomes easy to suppress noise by making the intrinsic mode different from the spatial mode of electromagnetic force.

FIG. 7 is a diagram showing an example of the relationship between the frequency of the electromagnetic excitation force and the resonance frequency of the stator in the synchronous motor according to the first embodiment.

For example, since the synchronous motor 20 is a motor with 10 poles and 12 slots, the pole logarithm p = 5. Further, it is assumed that the rotation speed of the synchronous motor 20 is r = 0 to 6000 [r / min] and the PWM frequency fc = 5500 [Hz]. In this case, the spatial mode is the annular elliptical mode, and the frequency range of the dominant electromagnetic excitation force is fc ± p × r / 60 [Hz], specifically 5500 ± 500 [Hz]. .. This frequency range is shown by hatching in FIG.

Under the above conditions, in FIG. 7, the frequency of the stator in which the first mold portion 7a is provided in all the slots 14 and the resonance frequency of the annular elliptical mode is 5000 [Hz] as the intrinsic mode. The relationship between response magnifications is shown by the solid line. In this case, the noise increases because the frequency range of the electromagnetic excitation force in the space mode in the annular elliptical mode matches the resonance frequency of the stator of 5000 [Hz].

On the other hand, in FIG. 7, the frequency and response magnification when the conditions of the mold portion are changed from the stator and the second mold portions 7b are provided at 120 degree intervals as in the stator 12 in the first embodiment. The relationship between is shown by a broken line.

In this case, the response magnification at the frequency of the ring ellipse mode in the eigenmode becomes smaller, and the resonance frequency of the stator is separated from the frequency range of the electromagnetic excitation force in the space mode. .. Therefore, the generation of noise is suppressed. For example, the resonance frequency of the ring ellipse mode is separated from the frequency range of the electromagnetic excitation force whose space mode is the ring ellipse mode, and the response magnification is set to -3 [dB] (≈1 / √2). The goal is to do. FIG. 8 is a diagram showing a frequency Δf at which the response magnification is -3 dB at the apex on both sides of the resonance peak when the resonance frequency is f0 and the mode attenuation ratio is ζ. The frequency width Δf for setting the response magnification at the resonance frequency to -3 [dB] is Δf = 2 × f0 × ζ. For example, when the resonance frequency f0 = 5000 [Hz] and the mode attenuation ratio ζ = 0.02, the frequency width Δf for setting the response magnification at the resonance frequency to -3 [dB] is Δf = 2 × f0. × ζ = 200 [Hz]. That is, the response magnification can be set to -3 [dB] by separating the resonance frequency from the frequency range of the electromagnetic excitation force by 100 [Hz] or more, which is Δf / 2.

By providing the second mold portions 7b at intervals of 120 degrees, the annular triangular mode is dominant in the intrinsic mode, so that the response magnification at the frequency in the annular triangular mode is large. However, in a 10-pole, 12-slot motor, the electromagnetic excitation force in which the space mode is the ring-triangular mode is not dominant, so that it does not lead to an increase in vibration and noise.

As a method of changing the resonance frequency, there is a method of increasing the resonance frequency by thickening the frame which is the housing of the synchronous motor. In this case, the synchronous motor becomes large. Further, as a method of changing the resonance frequency, there is a method of thinning the core back of the stator to lower the resonance frequency. In this case, the magnetic performance is lowered and the output is lowered.

In the synchronous motor 20 according to the first embodiment, the resonance frequency can be changed by adjusting the number and position of the second mold portions 7b. Therefore, it is possible to suppress the generation of vibration and noise while suppressing the increase in size and the decrease in output of the synchronous motor 20. It should be noted that at least one mold portion 7 may be the second mold portion 7b, or all the mold portions 7 may be the second mold portion 7b. Even in such a case, the resonance frequency of the stator can be reduced to obtain the effect of suppressing the generation of vibration and noise.

FIG. 9 is a diagram showing a mold used for manufacturing the stator according to the first embodiment. The mold 8 is used when forming the mold portion 7. The mold 8 has a cylindrical cylindrical portion 8a inserted inside the stator core 13 in which the winding portion 4 is formed. The cylindrical portion 8a has an outer diameter slightly larger than the region where the rotor 11 is arranged. The mold portion 7 is formed by pouring the resin into the stator core 13 with the cylindrical portion 8a inserted inside. The columnar portion 8a is formed with a protrusion 9 that is inserted between the enlarged portions 21 of the teeth 2 while being inserted inside the stator core 13.

At the place where the protrusion 9 has entered, the resin is not filled between the enlarged portions 21 of the teeth 2. The resin filled in the slot 14 in which the protrusion 9 is inserted becomes the second mold portion 7b. Where the protrusions 9 do not enter, resin is filled between the enlarged portions 21 of the teeth 2. The resin filled in the slot 14 in which the protrusion 9 does not enter becomes the first mold portion 7a. By using the mold 8 provided with the protrusions 9 that enter between the enlarged portions 21 of the teeth 2, the manufacturing of the mold portion 7 having the first mold portion 7a and the second mold portion 7b can be facilitated. Can be planned.

Further, by using the molds 8 having different positions of the protrusions 9, the arrangement of the first mold portion 7a and the second mold portion 7b can be easily changed. By changing the arrangement of the first mold portion 7a and the second mold portion 7b, the dominant unique mode in the stator can be easily selected. Therefore, it is possible to easily manufacture a stator whose unique mode does not match the spatial mode of the electromagnetic force of the synchronous motor.

Embodiment 2.
FIG. 10 is a partially enlarged cross-sectional view of a part of the teeth portion of the stator included in the synchronous motor according to the second embodiment. A detailed description of the same configuration as that of the first embodiment will be omitted.

In the second embodiment, the second mold portion 7b is joined to the surfaces where the enlarged portions 21 of the adjacent teeth 2 face each other. Further, a groove 71 is formed in the second mold portion 7b so as to be recessed outward in the radial direction. A gap is formed between the enlarged portions 21 of the adjacent teeth 2 by the groove 71.

Even when a gap is formed by the groove 71 between the enlarged portions 21 of the adjacent teeth 2, the rigidity is reduced in the second mold portion 7b portion to reduce the resonance frequency of the stator. , The effect of suppressing the generation of vibration and noise can be obtained. For example, the width D1 along the circumferential direction of the groove 71 may be 1/2 or less of the distance D2 between the enlarged portions 21 of the adjacent teeth 2.

When the gap 71 is formed by the groove 71, the width of the protrusion 9 formed on the mold 8 shown in FIG. 9 is formed to be narrower than the distance between the enlarged portions 21 of the adjacent teeth 2. Therefore, it becomes easy to insert the protrusion 9 between the enlarged portions 21 of the adjacent teeth 2, and the alignment of the mold 8 becomes easy. As a result, the manufacturing cost of the synchronous motor 20 can be reduced.

Further, the length of the groove 71 along the axial direction may be shorter than the length of the stator core 13 along the axial direction. Further, the grooves 71 formed in the plurality of second mold portions 7b may have different lengths along the axial direction. In this way, the resonance frequency of the stator can also be adjusted by the groove 71, and the degree of freedom of adjustment can be improved.

Further, the groove 71 may be formed in a tapered shape whose width changes along the axial direction or a tapered shape whose width changes along the radial direction. When the groove 71 is formed in a tapered shape, the protrusion 9 formed in the mold 8 shown in FIG. 9 is also formed in a tapered shape. As a result, the mold 8 can be easily removed after the mold portion 7 is formed, and the manufacturing cost of the synchronous motor 20 can be reduced. In addition, in order to facilitate the removal of the mold 8 when the groove 71 is formed in a tapered shape whose width changes along the radial direction, it is necessary to use a tapered shape in which the width becomes narrower toward the outer side in the radial direction. There is.

Further, when forming the mold portion 7, a fitting member (not shown) having a rigidity smaller than that of the mold portion 7 may be provided in the portion where the groove 71 is formed. In this case, after the mold portion 7 is formed, the fitting member is fitted in the groove 71. By using the fitting member, it is not necessary to form the protrusion 9 on the mold 8, the manufacturing cost of the mold 8 can be suppressed, and the life of the mold 8 can be extended. Further, since the fitting member has a lower rigidity than the mold portion 7, the rigidity of the second mold portion 7b portion is reduced to change the resonance frequency of the stator, thereby suppressing the generation of vibration and noise. Obtainable. When forming the second mold portion 7b shown in the first embodiment, the fitting member may be fitted between the enlarged portions 21 of the adjacent teeth 2.

Further, also in the second embodiment, at least one mold portion 7 may be the second mold portion 7b, or all the mold portions 7 may be the second mold portion 7b. Even in such a case, the resonance frequency of the stator can be reduced to obtain the effect of suppressing the generation of vibration and noise.

FIG. 11 is a diagram showing a modified example of the slot cell. As shown in FIG. 11, the peripheral end of the second cell portion 32 of the slot cell 3 may protrude from the circumferential end of the enlarged portion 21. For example, the peripheral end of the second cell portion 32 covers at least a part of the surface on which the enlarged portions 21 of the adjacent teeth 2 face each other. FIG. 11 shows an example in which the protruding portion of the second cell portion 32 extends along a surface facing the enlarged portions 21, but extends along a surface of the enlarged portion 21 facing outward in the radial direction. You may be. The configuration in which the circumferential end of the second cell portion 32 of the slot cell 3 protrudes from the circumferential end of the enlarged portion 21 may be applied to the slot 14 in which the first mold portion 7a is formed. , May be applied to the slot 14 in which the second mold portion 7b is formed.

The configuration shown in the above-described embodiment shows an example of the content of the present invention, can be combined with another known technique, and is one of the configurations without departing from the gist of the present invention. It is also possible to omit or change the part.

1 core back, 2 teeth, 3 slot cell, 4 winding part, 5 rotor core, 6 permanent magnet, 7 mold part, 7a first mold part, 7b second mold part, 8 mold, 8a columnar part , 9 protrusions, 11 rotors, 12 stators, 13 stator cores, 14 slots, 20 synchronous motors, 21 enlargement parts, 22 extension parts, 31 first cell parts, 32 second cell parts, 71 grooves.

Claims (11)

Cylindrical core back and
A plurality of teeth formed by projecting radially from the core back and arranging them in the circumferential direction,
The slot cell that covers the teeth and
A winding portion formed by winding a winding around the tooth via the slot cell,
A stator having a molded portion formed by filling resin between the adjacent teeth and a stator having the same.
The tooth has an extending portion extending in the radial direction from the core back and an expanding portion extending in the circumferential direction from the tip of the extending portion.
The slot cell includes a first cell portion that covers a surface of the core back that faces inward in the radial direction and an outer peripheral surface of the extension portion, and a second cell portion that covers a surface of the enlarged portion that faces outward in the radial direction. Have,
The circumferential end of the second cell portion coincides with the circumferential end of the enlarged portion, or the enlarged portions of the adjacent teeth cover at least a part of a surface facing each other.
The molded portion is a synchronous motor characterized in that a gap is formed between the enlarged portions of at least one adjacent tooth. The mold portion includes a plurality of first mold portions filled between the enlarged portions of the adjacent teeth and a plurality of first mold portions in which the gap is formed between the enlarged portions of the adjacent teeth. The synchronous motor according to claim 1, further comprising a mold portion of 2. A rotor provided inside the stator is provided.
The feature is that the shape having the apex between the tips of the teeth provided on both sides of the plurality of second mold portions and the shape of the space mode of the electromagnetic force when the rotor is rotated are different. The synchronous motor according to claim 2. The number of slots, which is the space between the teeth, is a multiple of 3 greater than or equal to 6.
The number of poles of the rotor is not a multiple of 3
The synchronous motor according to claim 3, wherein the second mold portion is provided at intervals of 120 degrees about the central axis of the core back. The second mold portion according to any one of claims 2 to 4, wherein the gap is formed by exposing the surfaces of the adjacent teeth to which the enlarged portions face each other. Synchronous motor. The second mold portion is joined to the surface of the adjacent teeth where the enlarged portions face each other, and the gap is formed by a groove formed so as to be recessed radially outward with respect to the second mold portion. The synchronous motor according to any one of claims 2 to 4, wherein the synchronous motor is formed. The synchronous motor according to claim 6, wherein the width of the groove is ½ or less of the distance between the enlarged portions of the adjacent teeth. The synchronous motor according to claim 6 or 7, wherein the length of the groove along the axial direction is different from the length of the core back along the axial direction. The synchronous motor according to any one of claims 6 to 8, wherein the grooves formed in the plurality of second mold portions have different lengths along the axial direction. The groove according to any one of claims 6 to 9, wherein the groove is formed in a tapered shape whose width changes along the axial direction or a tapered shape whose width changes along the radial direction. Synchronous motor. The synchronous motor according to any one of claims 1 to 10, further comprising a fitting member fitted in the gap.

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