JP2002101579A - Motor and compressor using thereof - Google Patents

Abstract

PROBLEM TO BE SOLVED: To reduce a sound in the neighborhood of carrier frequency in a motor of concentrated winding used in an air conditioner or compressor of a refrigerator. SOLUTION: The motor is provided with a plurality of slits extending in circumferential direction at the position opposite the bottom part of a slot of a yoke part, allowing the vibration of the yoke not to be transmitted to a shell of the compressor.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to the structure of a concentrated winding motor.

[0002]

2. Description of the Related Art A conventional technique will be described with reference to FIG.

As shown in FIG. 7, a conventional concentrated winding motor used for a compressor of an air conditioner or a refrigerator comprises a stator 60 and a rotor 80. The stator 60 has six teeth provided on a stator core 61. 62, three-phase windings 63U, 63V, 63W are applied directly via an insulator (insulating film, insulator, etc .: not shown).

[0004] The stator core 61 is provided with a tooth main body 64 on which a winding is applied, and a tooth front end 65 which is disposed at a front end of the tooth main body 64 and is generally wider than the tooth main body 64. And a substantially annular yoke 66 connecting the outer peripheral portions of the teeth main body 64.

The rotor 80 has a permanent magnet 82 buried in a permanent magnet burying hole 88 provided inside the rotor core 81, and end plates (not shown) are provided at both ends in the axial direction, and the rotor 80 is provided in the rotor core 81. A rivet (not shown) is passed through the formed through hole 83 and fixed by caulking.

[0006] The rotor 80 rotates the shaft 8 by a rotating magnetic field caused by a current flowing through a winding provided on the stator core 61.
It is rotating around 4.

The windings are of three phases of U, V and W phases, are star-connected to each other, and are 120 ° rectangular wave energization in which two of the three phases are energized and driven at the same time. The applied voltage can be changed by PWM control at a carrier frequency of 20 kHz or less.

The outer periphery of the stator core 61 has a substantially semicircular notch 67. This means that when the stator 60 is shrink-fitted and pressed into a compressor shell (not shown), a through hole is provided between the compressor shell and the stator core 61, and serves as a refrigerant passage.

[0009]

When a current flows from the U-phase to the V-phase, the teeth provided with the U-phase winding have N pole (or S pole), and the teeth provided with the V-phase winding have S pole (or N pole). The W phase has no polarity. At this time, since the magnetic flux flows from the N pole to the S pole, the teeth provided with the U-phase winding and the teeth provided with the V-phase winding attract each other at the tips. At this time, stress is applied to the teeth in a direction in which the teeth with the U-phase winding and the teeth with the V-phase winding attract each other, and the force is transmitted to the yoke part.
The yoke is mainly vibrated.

[0010] In the case of PWM driving, this force is excited by the carrier frequency.

As a result, compared with the distributed winding, the concentrated winding is more likely to cause the ring-shaped vibration (elliptical vibration) of the yoke, and the sound near the carrier frequency may increase. In particular, in the case of a four-pole motor, the above-described forces are concentrated at two places at 180-degree symmetric positions, so that elliptical vibration is particularly likely to occur and sound is likely to occur.

As a countermeasure, there is a method of increasing the damping by reducing the width of the yoke portion. However, this method reduces the width of the magnetic path, causes magnetic saturation, and produces no torque.
There were problems with magnetic properties, such as an increase in iron loss.

An object of the present invention is to reduce this electromagnetic noise as much as possible without sacrificing magnetic characteristics.

[0014]

In order to solve the above-mentioned problems, the present invention is characterized in that a plurality of slits which are long in the circumferential direction are provided at a position facing a slot bottom of a yoke. Was not transmitted to the compressor shell.

[0015]

According to a first aspect of the present invention, there is provided a motor comprising a rotor and a stator, wherein the plurality of stators extend radially with respect to the center of rotation of the rotor and are arranged at substantially equal intervals in the circumferential direction. A stator core comprising an annular yoke portion connecting the outer peripheral portion of the tooth portion to the outer peripheral portion of the tooth portion is formed by directly winding the tooth portion via an insulator, and the yoke portion is circumferentially long. A motor provided with a plurality of slits, which has an effect of preventing vibration of a yoke portion generated by attracting adjacent counter-electrode teeth from being transmitted to a shell of a compressor.

According to a second aspect of the present invention, in the motor according to the first aspect, the slit is provided at a position facing the bottom of the slot of the yoke portion. Because of the slit, transmission of vibration can be suppressed.

According to a third aspect of the present invention, in the motor according to the second aspect, the slit has a shape substantially similar to the outer periphery of the stator, the bottom of the slot, or both. The transmission of vibrations can be suppressed without obstructing the magnetic path.

According to a fourth aspect of the present invention, in the motor according to the second or third aspect, the number of slits provided is equal to the number of slots. it can.

The invention according to claim 5 is characterized in that the slit is provided in the middle between the outer periphery of the stator and the bottom of the slot or closer to the bottom of the slot than the slit. In the motor described above, it is possible to increase the attenuation of the vibration of the yoke caused by the attraction of the teeth of the adjacent counter electrodes.

According to a sixth aspect of the present invention, there is provided a magnetic path defined by a slit and a slot which are substantially similar to the shape near the intersection of the slot bottom and the both ends of the tooth in the width direction. Was made to be approximately the same width,
The motor according to any one of claims 2 to 5, wherein transmission of vibration can be further suppressed.

According to a seventh aspect of the present invention, there is provided means for fixing the respective core sheets, such as karamase, laser welding, and rivet caulking, only outside the slit provided in the yoke portion. Claim 2
The motor according to any one of claims 1 to 6, wherein the laminated stator core sheets attenuate each other,
Vibration transmission can be further suppressed.

According to an eighth aspect of the present invention, in the motor according to any one of the second to seventh aspects, the slit is filled with a resin, and the strength of the stator core at the time of press-fitting of the shrink fit. Can be improved.

According to a ninth aspect of the present invention, the slits are provided in a plurality of steps in the radial direction.
The motor according to any one of claims 1 to 8, wherein the width of each yoke divided by the slit can be reduced, and the attenuation of the annular vibration of the stator core can be increased.

According to a tenth aspect of the present invention, in the motor according to any one of the second to ninth aspects, the number of slots is 3N, and the rotor has a permanent magnet having 2N poles. Thus, transmission of vibration can be suppressed while maintaining particularly high torque density and high efficiency.

According to the eleventh aspect of the present invention, three slots
11. A phase winding, star connection, and driving by energizing two of three phases.
In the motor described above, the adjacent teeth serve as counter electrodes, so that ring vibration is easily generated, and the effect of the present invention is remarkable.

According to a twelfth aspect of the present invention, in the motor according to the tenth or eleventh aspect, the carrier frequency is a PWM drive having a carrier frequency of 20 kHz or less. Are matched, and resonance can be prevented.

According to a thirteenth aspect of the present invention, the motor according to any one of the first to twelfth aspects is mounted, and
This is a compressor in which a stator is shrink-fitted into a shell. In particular, the use of a vibration-proof material is restricted, so that vibration can be prevented without using a special vibration-proof material, which is preferable.

[0028]

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

FIG. 1 is a sectional view of a motor according to an embodiment of the present invention.

FIG. 2 is a sectional view of a compressor according to an embodiment of the present invention.

A concentrated winding motor used for a compressor of an air conditioner or a refrigerator includes a stator 10 and a rotor 80,
The stator 10 is directly connected to six teeth 12 provided on a stator core 11 via three-phase windings 13U, 13V, via an insulator (insulating film, insulator, etc., not shown).
13W.

The stator core 11 is provided with a tooth body 14 on which windings are wound, a tooth tip 15 which faces the outer periphery of the rotor and is disposed at the tip of the tooth body, and which is generally wider than the tooth body. A substantially annular yoke portion 16 is provided to connect the outer peripheral portions of the teeth body.

The rotor 80 is the same as a conventional motor, and a description thereof will be omitted.

The number of rotor poles is 4, and the number of status lots is 6.
Is a permanent magnet embedded type motor. In the interior magnet type, since the inductance increases, the amount of magnetic flux at the same current increases, and the exciting force tends to increase. Further, when a rare earth magnet (neodymium-iron-boron-based) is used as the permanent magnet, the coercive force is large, so that the exciting force further increases.

The three-phase windings 13U, 13V, and 13W are star-connected to each other, and are 120 ° rectangular-wave energization in which two of the three phases are energized and driven at the same time. Here, by always keeping one of the three phases de-energized, the induced voltage can be detected, and sensorless control can be performed. However, in the case of the rectangular wave energization, when the energization is turned on and off, the current flowing through the windings changes greatly in a short time, so that a large excitation force is generated here. In particular, in concentrated winding, winding of only one phase is applied to one tooth, so that the turning on and off of the current directly affects the change in magnetic flux generated in the teeth, and vibration and noise are particularly remarkable. It becomes.

The applied voltage has a carrier frequency of 20 k.
It is changed by PWM control below Hz. The smaller the carrier frequency, the smaller the switching loss,
The efficiency of the motor including the circuit is increased. Usually, it is often set in the range of 2 kHz or more and 7 kHz or less,
If it is less than 20 kHz, it will be in the audible frequency range.
Noise due to the carrier frequency will be heard. In particular, during low-load operation in which the duty ratio is small, noise due to the carrier frequency becomes remarkable. In the case of air conditioners and refrigerator compressors, the load during stable operation is decreasing year by year (in the case of air conditioners, the indoor insulation is improved, and in the case of refrigerators, the internal heat insulation is improved). The ratio is decreasing.

The yoke portion 16 is provided with six slits 17 long in the rotation direction. When the number of slits is equal to the number of slots, the vibration-proofing effect becomes remarkable. Slit 1
7 is located at the center of the bottom portion 18b of the slot 18 and the outer peripheral portion 11o of the stator core, or at the bottom portion 18b
It is provided near. The annular vibration of the yoke caused by the excitation force acting on the teeth is mainly determined by the width of the yoke inside the slit 17. Therefore, when the slit position is set as described above, it is possible to reduce rigidity and increase attenuation. In addition, the natural frequency can be reduced. FIG. 3 shows the relationship between the slit position and the natural frequency of the elliptic mode. The natural frequency decreases as the position of the slit approaches the bottom of the slot. In addition, the slit position is good at the bottom of the slot and the center of the stator outer diameter part because of the strength when shrink-fitting the stator to the shell and the uniformity of the magnetic flux flowing through the yoke. , May be further provided near the bottom of the slot.

The length of the slit 17 is substantially equal to the length of the slot bottom 18b. The slot bottom here means the slot 18 itself as a slot side portion 18s which is both ends in the width direction of the tooth body portion 14 extending in the radial direction, a slot bottom portion 18b, and the tooth tip portion 1.
5 is a range including a fillet or a chamfer near the intersection of the slot bottom 18b and the slot side 18s when the slot entrance 18i at both ends in the width direction is used, but may be slightly shorter than this. .

The slit shape is a circular arc shape similar to the slot bottom portion 18b and / or the stator core outer peripheral portion 11o, and the slit width is preferably as small as possible. In this case, the width of the yoke as the magnetic path is uniform, and the flow of the magnetic flux is smooth, so that the iron loss can be reduced. The slit width is
It is preferably about 0.2 mm to 0.3 mm (or 0.5 mm or less).

At this time, when viewed in the rotational direction, the slit 17
In the area where there is no
By having 7, there is no contact with the shell 20 of the compressor. That is, a portion of the outer periphery of the stator core in which the teeth body is extended in the radial direction is apart from the compressor shell 20, and the other portion has a slit 17 in the yoke 16. Here, the cutout may be a substantially semicircular, rectangular, or linear cutout.

The notch 27 is provided in the stator 1
When 0 is shrink-fitted into the shell 20 of the compressor, the through-hole is provided between the shell 20 of the compressor and the stator core 11 and serves as a refrigerant passage.

When the adjacent teeth serve as counter electrodes, they vibrate in a shape as shown in FIG. Here, the force for deforming the yoke vibrates inside the slit 17 or is not transmitted to the compressor shell 20 due to the notch 27. Therefore, if the natural frequency of the stator core is made appropriate, the shell 20
Irrespective of the natural frequency, it is possible to reduce noise particularly caused by resonance due to the carrier frequency.

When the motor having the above configuration is used in a hermetic compressor used in an air conditioner, a refrigerator or the like in which the vibration-proof material cannot be used freely, the present method without using the vibration-proof material is suitable. In particular, like a scroll type compressor,
When shrink-fitting the outer periphery of the stator core to the shell 20,
This is particularly effective because the vibration of the stator core is likely to be directly transmitted to the vibration of the shell 20 as it is.

If the slit 17 is filled with an elastic substance (usually resin) such as plastic or rubber, the radial strength may be increased. Polyester films such as PET and PBT hardly affect the refrigerant particularly in the case of a compressor or the like used in a refrigerant. Also, if you use a plastic containing a magnetic material (especially a ferromagnetic material) such as iron powder,
The magnetic flux easily passes, and the deterioration of the characteristics can be suppressed. Note that the material to be filled in the slit 17 needs to be a material having lower rigidity and higher elasticity than iron.

If the means for fixing the stator core sheet forming the stator core (such as karamase, laser welding, rivet caulking, bolting, etc.) is provided outside the slit 17, the portion inside the slit 17 is fixed to each other. Because they can be vibrated separately, the damping is high.

As shown in FIG. 5, the slot bottom 1
8b and slot side portions 18 at both ends in the width direction of the teeth
A slit 24 that is substantially similar to the shape near the intersection of s may be additionally provided, and the width of the magnetic path defined by the slit 24 and the slot 18 may be substantially equal. Thereby, when transmitting the vibration of the teeth to the yoke, it can be further attenuated. In addition, slits may be provided in the teeth body and the like. That is, a slit that does not obstruct the magnetic path of the stator core may be provided to attenuate the exciting force acting on the teeth.

As shown in FIG. 6, the slits 34 may be provided in a plurality of stages in the radial direction. At this time, the total width of the slits increases, and the width of the yoke as the magnetic path decreases. However, since the width of the yoke divided by the slits 34 decreases, the attenuation of the annular vibration increases, and the noise around the carrier frequency increases. Can be reduced.

The shape of the rotor and the shape of the stator and the number of poles of the motor are arbitrary. Further, the compressor is not limited to the case where the outer periphery of the stator core is shrink-fitted to the shell, but may be bolted or the like.

[0049]

As is clear from the description of the above embodiment,
According to the first aspect of the present invention, the vibration of the yoke generated by the attraction of the teeth of the adjacent counter electrodes is prevented from being transmitted to the shell of the compressor, so that the noise can be reduced.

According to the second aspect of the present invention, since there is a slit at the antinode of the ring vibration, transmission of the vibration can be suppressed.

According to the third aspect of the present invention, transmission of vibration can be suppressed without obstructing the magnetic path of the yoke portion.

According to the fourth aspect of the present invention, transmission of vibration can be further suppressed.

According to the fifth aspect of the invention, it is possible to increase the attenuation of the vibration of the yoke caused by the attraction of the teeth of the adjacent counter electrodes.

According to the invention described in claim 6, transmission of vibration can be further suppressed.

According to the seventh aspect of the present invention, the laminated stator core sheets can be attenuated, and the transmission of vibration can be further suppressed.

According to the present invention, the strength of the stator core at the time of press-fitting of shrink fit can be improved.

According to the ninth aspect, the width of each yoke divided by the slit can be reduced, and the attenuation of the annular vibration of the stator core can be increased.

According to the tenth aspect, the transmission of vibration can be suppressed while maintaining particularly high torque density and high efficiency.

According to the eleventh aspect of the present invention, since the adjacent teeth serve as counter electrodes, the ring vibration is easily generated, and the effect of the present invention is remarkable.

According to the twelfth aspect, the carrier frequency and the natural frequency of the stator core coincide with each other, and it is possible to prevent resonance.

According to the thirteenth aspect, it is possible to perform vibration isolation without using a special vibration isolation material.

[Brief description of the drawings]

FIG. 1 is a sectional view of a motor according to an embodiment of the present invention.

FIG. 2 is a sectional view of a compressor according to an embodiment of the present invention.

FIG. 3 is a diagram showing a relationship between a slit position and a natural frequency.

FIG. 4 is a diagram illustrating a vibration mode of a stator core.

FIG. 5 is a cross-sectional view of another example of the motor according to the embodiment of the present invention.

FIG. 6 is a sectional view of another example of the motor according to the embodiment of the present invention;

FIG. 7 is a sectional view of a conventional motor.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 10 Stator 11 Stator core 12 Teeth 13U, 13V, 13W Winding 14 Teeth main part 15 Teeth tip part 16 Yoke part 17 Slit 18 Slot 20 Shell

──────────────────────────────────────────────────の Continued on the front page (51) Int.Cl. ⁷ Identification code FI Theme coat ゛ (Reference) H02P 6/08 H02P 6/02 351J (72) Inventor Hisakazu Kataoka 1006 Kazuma Kadoma, Kadoma City, Osaka Matsushita Electric Inside Sangyo Co., Ltd. (72) Inventor Toshiyuki Tamamura 1006 Kadoma Kadoma, Osaka Prefecture Matsushita Electric Industrial Co., Ltd. (72) Inventor Eiji Hinokiwaki 1006 Okadoma Kadoma, Kadoma City, Osaka Matsushita Electric Industrial Co., Ltd. ) 3H003 AC03 CF04 5H002 AA04 AB06 AC02 AC03 AC10 AE08 5H560 AA02 BB04 BB07 BB12 BB18 DA13 EC02 JJ12 JJ13 XA12 5H621 AA04 BB10 GA01 GA04 GA12 GA14 GA18 HH08 JK05 PP10 5H622 AA03 CA05 CA07 CA13 PP

Claims (13)

[Claims] 1. A motor comprising a rotor and a stator, wherein the stator extends in a radial direction with respect to a center of rotation of the rotor, and a plurality of teeth arranged at substantially equal intervals in a circumferential direction, and an outer peripheral portion of the teeth. A stator core comprising an annular yoke portion, wherein the teeth portion is directly wound with an insulating material interposed therebetween, and the yoke portion is provided with a plurality of circumferentially long slits. motor. 2. The motor according to claim 1, wherein the slit is provided at a position facing the bottom of the slot of the yoke portion. 3. The motor according to claim 2, wherein the slit has a shape substantially similar to the outer periphery of the stator, the bottom of the slot, or both. 4. The motor according to claim 2, wherein the same number of slits as the number of slots are provided. 5. The motor according to claim 2, wherein the slit is provided between the outer periphery of the stator and the bottom of the slot or closer to the bottom of the slot. 6. A slit near the intersection of the slot bottom and the widthwise ends of the teeth has a slit that is substantially similar in shape, and the width of the magnetic path defined by the slit and the slot is substantially equal to the width. The motor according to any one of claims 2 to 5, wherein: 7. The apparatus according to claim 2, further comprising means for fixing between the core sheets, such as karamase, laser welding, and rivet caulking, only outside the slit provided in the yoke portion. 7. The motor according to any one of 6. 8. The motor according to claim 2, wherein the slit is filled with a resin. 9. The motor according to claim 2, wherein the slits are provided in a plurality of stages in the radial direction. 10. The number of slots is 3N and the number of slots is 2
3. A permanent magnet having a north pole.
The motor according to any one of claims 1 to 9. 11. The motor according to claim 10, wherein the slots are provided with three-phase windings, star-connected, and driven by energizing two of the three phases. 12. A P having a carrier frequency of 20 kHz or less.
The motor according to claim 10 or 11, wherein the motor is a WM drive. 13. A compressor mounted with the motor according to claim 1 and having a stator press-fit into a shell.