JP2004007875A - Permanent magnet type electric motor and compressor employing it - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a high output low noise permanent magnet type electric motor. <P>SOLUTION: The permanent magnet type electric motor 11 comprises a stator 7 having a concentrated armature winding 9 surrounding the tees 10 in a plurality of slots 13 formed in the stator core 12, and a rotor 1 having permanent magnets 3 contained in a plurality of permanent magnet insertion holes 14 formed in the rotor core 2. The pole angle θ1 of the rotor core 2 is set in a range of electric angle of 100-120° and a recess 15 is formed in the outer circumferential surface of the rotor core 2 between the poles thus ensuring a high output while reducing noise. <P>COPYRIGHT: (C)2004,JPO

Description

[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to a permanent magnet type rotating electric machine having a permanent magnet for a field in a rotor, and more particularly to a permanent magnet type rotating electric machine mounted on a compressor such as an air conditioner, a refrigerator and a freezer.
[0002]
[Prior art]
Conventionally, various shapes have been adopted in this type of permanent magnet type rotating electric machine. For example, in a permanent magnet type rotating electric machine described in Japanese Patent Application Laid-Open No. 2001-218404, a stator in which concentrated winding armature winding is provided so as to surround a plurality of teeth formed in a stator core, A rotor in which permanent magnets are accommodated in a plurality of permanent magnet insertion holes formed in a child iron core, and magnet torque is effectively generated to improve the output of the rotating electric machine.
[0003]
[Problems to be solved by the invention]
Although the above prior art focuses on improving the output of the rotating electric machine, it cannot be considered that the noise problem is separated in order to put it into practical use as the rotating electric machine. Factors that increase the noise of the permanent magnet type rotating electric machine include a pulsating torque and an electromagnetic excitation force, and these can be reduced by reducing the magnetic flux density of the gap. However, simply reducing the magnetic flux density of the gap by simply widening the gap increases the magnetic resistance and reduces the magnetic flux generated from the permanent magnet, so that the magnet torque decreases and the output decreases. Therefore, it is necessary to reduce only the magnetic flux that causes noise while increasing the magnetic flux that contributes to the magnet torque.
[0004]
An object of the present invention is to provide a permanent magnet type rotating electric machine that can solve the noise problem while improving the output.
[0005]
[Means for Solving the Problems]
In order to achieve the above object, according to the present invention, there are provided a stator in which an armature winding is provided in a plurality of slots formed in a stator core, and a plurality of permanent magnet insertion holes formed in a rotor core. In a permanent magnet type rotating electric machine having a rotor in which a permanent magnet is accommodated, a magnetic pole angle of the rotor core is set to an electric angle in a range of 100 degrees to 120 degrees, and a gap between the outer circumferential surface of the rotor core. We propose a permanent magnet type rotating electric machine with a recess.
[0006]
According to the present invention, a stator in which concentrated armature windings are provided to surround teeth in a plurality of slots formed in the stator core, and a plurality of permanent magnets formed in the rotor core are inserted. In a permanent magnet type rotating electric machine having a rotor in which a permanent magnet is accommodated in a hole, the magnetic pole angle of the rotor core is made substantially the same as the slot pitch of the stator core, and the distance between the poles on the outer peripheral surface of the rotor core is We propose a permanent magnet type rotating electric machine in which a recess is formed.
[0007]
According to the present invention, further, a stator in which concentrated winding armature winding is applied to surround the teeth in a plurality of slots formed in the stator core, and a plurality of permanent magnets formed in the rotor core are inserted. In a permanent magnet type rotating electric machine having a rotor in which a permanent magnet is accommodated in a hole, the magnetic pole angle of the rotor core is made substantially the same as the slot pitch of the stator core, and the distance between the poles on the outer peripheral surface of the rotor core is We propose a permanent magnet type rotating electric machine in which a recess is formed.
[0008]
The present invention further provides a stator in which concentrated winding armature winding is applied to surround the teeth in a plurality of slots formed in the stator core, and a plurality of permanent magnets inserted in the rotor core. In a permanent magnet type rotating electric machine having a rotor in which a permanent magnet is accommodated in a hole and the ratio of the number of poles of the rotor to the number of slots of the stator is 2: 3, the magnetic pole angle of the rotor core is The present invention proposes a permanent magnet type rotating electric machine having an electrical angle in a range of 100 degrees to 120 degrees and a recess formed between poles on an outer peripheral surface of a rotor core.
[0009]
According to the present invention, further, a stator in which concentrated winding armature winding is applied to surround the teeth in a plurality of slots formed in the stator core, and a plurality of permanent magnets formed in the rotor core are inserted. In a permanent magnet type rotating electric machine having a rotor in which a permanent magnet is accommodated in a hole and a ratio of the number of poles of the rotor to the number of slots of the stator is 2: 3, a tooth tip shape of a stator iron core is provided. Between the poles on the outer peripheral surface of the rotor core so that the magnetic pole angle of the rotor core is in the range of 100 degrees to 120 degrees in electrical angle, together with the shape combining the arc-shaped portion and the linear portion. We propose a permanent magnet type rotating electric machine with a recess.
[0010]
Various experiments have shown that in order to reduce noise while improving the output of a permanent magnet type rotating electric machine, it is only necessary to increase the magnetic flux of the permanent magnet contributing to the generation of magnet torque and reduce only the armature reaction magnetic flux. Found through. Here, since the armature reaction magnetic flux generally advances the magnetic flux of the permanent magnet by approximately 90 degrees in electrical angle, the rotor core shape called the horizontal axis (q axis) inductance and the armature winding That is, it is only necessary to reduce the inductance generated based on the coupling with the above.
[0011]
The present invention is based on this experimental result, and has a concave portion between the poles (q-axis side) on the outer peripheral surface of the rotor core so that the magnetic pole angle of the rotor core is in the range of 100 to 120 degrees in electrical angle. With the formation, the magnetic flux of the permanent magnet linked to the armature winding increases, and the inductance of the horizontal axis decreases, so that the armature reaction magnetic flux can be reduced. Therefore, it is possible to provide a permanent magnet type rotating electric machine with improved output and low noise.
[0012]
BEST MODE FOR CARRYING OUT THE INVENTION
Hereinafter, embodiments of the present invention will be described in detail with reference to FIGS. In each of the drawings, common symbols indicate the same items. Also, a four-pole permanent magnet type rotating electric machine is shown here.
[0013]
(Embodiment 1)
FIG. 1 shows a radial cross section of a permanent magnet type rotating electric machine according to a first embodiment of the present invention. In the figure, a permanent magnet type rotating electric machine 11 includes a stator 7 and a rotor 1. The stator 7 includes a stator core 12 including teeth 10 and a core back 8, and a concentrated winding armature winding 9 (three-phase winding) wound around the teeth 10 in a slot 13 between the teeth 10. U-phase winding 9a, V-phase winding 9b, and W-phase winding 9c). Here, since the permanent magnet type rotating electric machine 11 has four poles and six slots, the slot pitch is 120 degrees in electrical angle.
[0014]
FIG. 2 is an enlarged cross-sectional shape in the radial direction of the rotor according to the first embodiment of the present invention. The rotor 1 has a one-character permanent magnet insertion hole 14 formed in the rotor core 2 in which the permanent magnet 3 is accommodated, and includes a shaft hole 6 for fitting with a shaft (not shown). Here, an axis extending in the direction of the center of the magnetic pole of the rotor 1 is defined as a d-axis, and an axis extending in the direction between the magnetic poles separated from the center of the magnetic pole by an electrical angle of 90 degrees is defined as the q-axis. In FIG. 2, the shape between the poles (q axis) of the outer peripheral surface of the rotor core 2 is set to a concave shape (a shape obtained by combining two substantially V-shaped concave portions), and the magnetic pole angle θ1 of the rotor core 2 is set to the slot pitch. And almost equal.
[0015]
FIG. 10 shows a radial cross-sectional shape of the rotor of the comparative example. When the permanent magnet 3 is embedded in the rotor core 2, the magnetic flux of the permanent magnet 3 is likely to be short-circuited. Therefore, also in the comparative example, the gap between the outer peripheral surfaces of the rotor core 2 (q-axis side) is formed into a concave shape. The short circuit of the magnetic flux is prevented, and the torque by the magnetic flux is increased. However, since the purpose of forming the gap between the poles into a concave shape is to prevent a short circuit of the magnetic flux, the concave portion 15 is parallel to the side surface of the permanent magnet insertion hole 14.
[0016]
By the way, in the compressor driving permanent magnet type rotary electric machine 11 to which the present invention is applied, noise often becomes a problem. Factors that increase the noise of the permanent magnet type rotating electric machine 11 include a pulsating torque and an electromagnetic excitation force, and these can be reduced by reducing the magnetic flux density of the gap. However, simply reducing the magnetic flux density of the gap by simply widening the gap increases the magnetic resistance and reduces the magnetic flux generated from the permanent magnet, so that the magnet torque decreases and the output decreases. Therefore, through various experiments, it has been found that it is necessary to reduce only the armature reaction magnetic flux which is a cause of noise without reducing the magnetic flux of the permanent magnet which contributes to the magnet torque. Here, the armature reaction magnetic flux generally advances the magnetic flux of the permanent magnet by approximately 90 degrees in electrical angle, so that the horizontal axis (q-axis) inductance may be reduced.
[0017]
FIG. 11 is a diagram showing characteristics of the permanent magnet type rotating electric machine with respect to the magnetic pole angle θ1. The horizontal axis indicates the magnetic pole angle θ1 in electrical angle, and the vertical axis indicates the induced electromotive force and the horizontal axis inductance of the rotating electric machine of the comparative example (FIG. 10, θ1 = 148 degrees) by 1.0 p. u. The induced electromotive force and the horizontal axis inductance when normalized as are shown. Here, since the induced electromotive force is proportional to the time change (dφ / dt) of the magnetic flux φ linked to the armature winding 9, the increase / decrease of the magnetic flux of the permanent magnet contributing to the generation of the magnet torque depends on the magnitude of the induced electromotive force. Can be determined.
[0018]
From FIG. 11, it can be seen that the smaller the magnetic pole angle θ1, the larger the gap (gap), the lower the horizontal axis inductance. However, it can be seen that there is almost no change when θ1 = 120 degrees or less. Therefore, in order to reduce noise, it is sufficient to make θ1 as small as possible, and it is understood that θ1 is preferably 120 ° or less.
[0019]
On the other hand, the induced electromotive force is larger than that of the comparative example when θ1 is about 80 degrees or more, but smaller than that of the conventional machine when θ1 is about 80 degrees or less. The induced electromotive force is proportional to the time change of the magnetic flux linked to the armature winding 9, but in the case of concentrated winding, since the armature winding 9 is applied so as to surround the teeth 10, the magnetic flux flowing into the teeth 10 is The magnetic flux interlinks with the winding 9. In the permanent magnet type rotating electric machine 11 in which the ratio between the number of poles of the permanent magnet 3 and the number of the slots 13 is 2: 3, the slot pitch is 120 degrees in electrical angle, so that the magnetic pole angle θ1 can be made substantially equal to the slot pitch. Thus, the magnetic flux of the permanent magnet 3 can be effectively used. Therefore, the maximum is obtained when θ1 = 120 degrees, but hardly changes when θ1 is in the range of 100 degrees to 140 degrees.
[0020]
As described above, if the magnetic pole angle θ1 is set in the range of approximately 100 degrees to 120 degrees, the output of the motor can be improved and noise can be reduced.
[0021]
(Embodiment 2)
FIGS. 3 and 4 are enlarged sectional views of the rotor 1 of Embodiment 2 of the permanent magnet type rotating electric machine according to the present invention, showing a radial cross-sectional shape of the rotor. The second embodiment shown in FIGS. 3 and 4 differs from the first embodiment in FIG. 2 in that a slit portion 4 is provided in a magnetic pole portion of a rotor core 2. Although two slits 4 are provided symmetrically with respect to the d-axis in the magnetic pole portion of the rotor 1 in FIG. 3, one slit 4 is provided on the d-axis in FIG.
[0022]
FIG. 12 is a diagram showing characteristics with respect to an angle θ2 between slit portions provided in a rotor magnetic pole portion of a permanent magnet type rotating electric machine. The horizontal axis indicates the angle θ2 between the slits 4 in electrical angle, and the vertical axis indicates the induced electromotive force and the horizontal axis inductance of the conventional machine (FIG. 10) by 1.0 p. u. The induced electromotive force and the horizontal axis inductance when normalized as are shown. Therefore, the slit portion 4 is closer to the gap (q axis) as θ2 is larger, and the slit portion 4 is closer to the magnetic pole center (d axis) as θ2 is smaller. Here, when θ2 = 0 degrees, as shown in FIG. 4, there is one slit portion 4 on the d-axis, and the width W2 of the slit portion 4 is set to twice W1 (W2 = 2 × W1). . In addition, the result is that the magnetic pole angle θ1 is constant at 120 degrees, and FIG. u. , The horizontal axis inductance is 0.83 p. u. It is.
[0023]
The induced electromotive force slightly decreases by providing the slit portion 4, and tends to decrease as the angle θ2 decreases, but is larger than that of the comparative example. On the other hand, the horizontal axis inductance is reduced by providing the slit portion, and is significantly reduced as the angle θ2 is reduced. Therefore, when the magnetic pole angle θ1 is set in a range of approximately 100 degrees to 120 degrees and the slit portion 4 is provided in the magnetic pole portion of the rotor 1, the output is higher than that of the comparative example and noise can be reduced. From the viewpoint of noise reduction, the position of the slit portion 4 is optimally at the center of the magnetic pole (on the d-axis).
[0024]
(Embodiment 3)
FIG. 5 is an enlarged sectional view of the rotor 1 of the permanent magnet type rotary electric machine according to Embodiment 3 of the present invention, showing a radial cross-sectional shape of the rotor. The third embodiment shown in FIG. 5 differs from the first embodiment in FIG. 2 in that the shape of the permanent magnet 3 is V-shaped. Also in the third embodiment, the same effect as that of the first embodiment in FIG. 2 can be obtained.
[0025]
(Embodiment 4)
6 and 7 are enlarged sectional views of the rotor 1 of Embodiment 4 of the permanent magnet type rotating electric machine according to the present invention, showing a radial sectional shape of the rotor. The fourth embodiment shown in FIGS. 6 and 7 differs from the third embodiment in FIG. 5 in that a slit portion 4 is provided in the magnetic pole portion of the rotor core 2. In FIG. 6, two slits 4 are provided in the magnetic pole portion of the rotor 1 symmetrically with respect to the d axis, but in FIG. 7, one slit 4 is provided on the d axis.
[0026]
When the slit portion 4 is provided after the magnetic pole angle θ1 is set in a range of approximately 100 degrees to 120 degrees, the magnetic flux of the permanent magnet 3 can be effectively used, and the horizontal axis inductance can be reduced, so that the output of the motor is improved, and Low noise can be achieved. From the viewpoint of noise reduction, the position of the slit portion 4 is optimally at the center of the magnetic pole (on the d-axis).
[0027]
(Embodiment 5)
FIG. 8 is a diagram showing a sectional shape of a fifth embodiment of the permanent magnet type rotating electric machine according to the present invention. The fifth embodiment shown in FIG. 8 differs from the first embodiment in FIG. 1 in that the tip of the stator teeth 10 has a shape combining an arc-shaped portion and a linear portion.
[0028]
With such a structure, the gap length at the end of the tooth 10 is increased, so that the magnetic flux concentration at the end of the tooth 10 is reduced, and the pulsating torque is reduced.
[0029]
Therefore, the noise can be significantly reduced by combining with the rotor 1 shown in the first to fourth embodiments.
[0030]
(Embodiment 6)
FIG. 9 is a diagram showing a cross-sectional shape of Embodiment 6 of the permanent magnet type rotating electric machine according to the present invention. Embodiment 6 shown in FIG. 9 is different from Embodiments 1 and 5 in that an armature winding 9 is provided in a slot 13 in the order of a U-phase winding 9a, a V-phase winding 9b, and a W-phase winding 9c. That is, the distribution windings are sequentially stored.
[0031]
As described above, even when the winding method of the armature winding 9 is different, by combining with the rotor 1 shown in the first to fourth embodiments, the magnetic flux of the permanent magnet 3 can be effectively used and the horizontal axis inductance can be improved. Can be reduced, so that the output of the motor can be improved and noise can be reduced.
[0032]
(Embodiment 7)
FIG. 13 shows a cross-sectional structure of the compressor according to the present invention. The compressor is formed by meshing a spiral wrap 19 standing upright on the end plate 18 of the fixed scroll member 17 and a spiral wrap 22 standing upright on the end plate 21 of the orbiting scroll member 20, and turning the orbiting scroll member 20 into the crank. The compression operation is performed by turning the shaft 23. Of the compression chambers 24 (24a, 24b,...) Formed by the fixed scroll member 17 and the orbiting scroll member 20, the compression chamber located on the outermost side is the two scroll members 17, 20 with the orbital motion. Moving toward the center of the car and the volume gradually decreases. When the compression chambers 24a and 24b reach the vicinity of the centers of the scroll members 17 and 20, the compressed gas in the compression chambers 24 is discharged from the discharge port 25 communicating with the compression chamber 24. The discharged compressed gas passes through a fixed scroll member 17 and a gas passage (not shown) provided in the frame 26 to reach a compression container 27 below the frame 26, and a discharge pipe provided on a side wall of the compression container 27. It is discharged out of the compressor from 28. In this compressor, the permanent magnet type rotating electric machine 11 is enclosed in the pressure vessel 27, and rotates at a rotation speed controlled by a separate inverter (not shown) to perform a compression operation. Here, the driving motor is a permanent magnet type rotating electric machine 11 including the stator 7 and the rotor 1.
[0033]
Compressors are used as a driving source for air conditioners, refrigerators, freezers, etc., but are operating all year round, and are therefore the most important products for energy saving due to the problem of global warming. If a permanent magnet type rotating electric machine is used as this drive source, energy saving can be achieved by increasing the efficiency of the rotating electric machine, but it cannot be adopted unless noise is reduced. However, when the permanent magnet type rotating electric machine of the present invention is used as a driving source, noise can be reduced and environmental problems can be solved, so that a compressor that can achieve high efficiency and energy saving can be provided.
[0034]
【The invention's effect】
As described above, according to the present invention, the induced electromotive force of the permanent magnet type rotating electric machine increases and the horizontal axis inductance decreases, so that a high output and low noise permanent magnet type rotating electric machine can be provided.
[0035]
Further, according to the present invention, a compressor with low noise can be provided.
[Brief description of the drawings]
FIG. 1 is a cross-sectional view showing a radial cross-sectional shape of a first embodiment of a permanent magnet type rotating electric machine according to the present invention.
FIG. 2 is an enlarged cross-sectional view illustrating a radial cross-sectional shape of the rotor of FIG. 1;
FIG. 3 is an enlarged cross-sectional view illustrating a radial cross-sectional shape of the rotor of a permanent magnet type rotating electric machine according to a second embodiment of the present invention;
FIG. 4 is an enlarged cross-sectional view showing a radial cross-sectional shape of the rotor of a permanent magnet type rotating electric machine according to a second embodiment of the present invention;
FIG. 5 is an enlarged sectional view of a rotor of a permanent magnet type rotating electric machine according to a third embodiment of the present invention, showing a radial sectional shape of the rotor;
FIG. 6 is an enlarged cross-sectional view illustrating a radial cross-sectional shape of the rotor of a permanent magnet type rotating electric machine according to a fourth embodiment of the present invention;
FIG. 7 is an enlarged sectional view of a rotor of a permanent magnet type rotating electric machine according to a fourth embodiment of the present invention, showing a radial cross-sectional shape of the rotor.
FIG. 8 is a cross-sectional view showing a radial cross-sectional shape of a fifth embodiment of the permanent magnet type rotating electric machine according to the present invention.
FIG. 9 is a sectional view showing a radial cross section of a permanent magnet type rotating electric machine according to a sixth embodiment of the present invention.
FIG. 10 is a cross-sectional view illustrating a radial cross-sectional shape of a permanent magnet type rotating electric machine of a comparative example.
FIG. 11 is a view showing characteristics of the permanent magnet type rotating electric machine according to the first embodiment.
FIG. 12 is a diagram showing characteristics of the permanent magnet type rotating electric machine according to the second embodiment.
FIG. 13 is a sectional view of a compressor according to the present invention.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 1 ... rotor, 2 ... rotor core, 3 ... permanent magnet, 4 ... slit part, 6 ... shaft fitting hole, 7 ... stator, 8 ... core back, 9 ... armature winding, 10 ... teeth, 11 ... permanent magnet type rotating electric machine, 12 ... stator core, 13 ... slot, 14 ... permanent magnet insertion hole, 15 ... rotor core recess, 17 ... fixed scroll member, 18, 21 ... end plate, 19, 22 ... wrap, Reference numeral 20: orbiting scroll member, 23: shaft, 24: compression chamber, 25: discharge port, 26: frame, 27: compression container, 28: discharge pipe, 29: oil reservoir, 30: oil hole, 31: sliding bearing.

Claims (10)

It has a stator in which armature winding is provided in a plurality of slots formed in the stator core, and a rotor in which permanent magnets are accommodated in a plurality of permanent magnet insertion holes formed in the rotor core. And
The magnetic pole angle of the rotor core is in the range of 100 degrees to 120 degrees in electrical angle,
A permanent magnet type rotating electric machine wherein a recess is formed between poles on an outer peripheral surface of the rotor core. A stator in which concentrated winding armature winding is applied to surround the teeth in a plurality of slots formed in the stator core,
Having a rotor in which permanent magnets are accommodated in a plurality of permanent magnet insertion holes formed in the rotor core,
A permanent magnet type rotating electric machine, wherein a magnetic pole angle of the rotor core is substantially equal to a slot pitch of the stator core, and a recess is formed between poles on an outer peripheral surface of the rotor core. A stator in which concentrated winding armature winding is applied to surround the teeth in a plurality of slots formed in the stator core,
A rotor having a permanent magnet housed in a plurality of permanent magnet insertion holes formed in the rotor core,
The teeth tip shape of the stator core is a combination of an arc-shaped portion and a linear portion,
A permanent magnet type rotating electric machine wherein a recess is formed between poles on an outer peripheral surface of the rotor core so that a magnetic pole angle of the rotor core is substantially equal to a slot pitch of the stator core. A stator in which concentrated winding armature winding is applied to surround the teeth in a plurality of slots formed in the stator core,
Having a rotor in which permanent magnets are accommodated in a plurality of permanent magnet insertion holes formed in the rotor core,
The ratio between the number of poles of the rotor and the number of slots of the stator is 2: 3,
The magnetic pole angle of the rotor core is in the range of 100 degrees to 120 degrees in electrical angle,
A permanent magnet type rotating electric machine wherein a recess is formed between poles on an outer peripheral surface of the rotor core. A stator in which concentrated winding armature winding is applied to surround the teeth in a plurality of slots formed in the stator core,
Having a rotor in which permanent magnets are accommodated in a plurality of permanent magnet insertion holes formed in the rotor core,
A ratio of the number of poles of the rotor to the number of slots of the stator is 2: 3,
The teeth of the stator core have a shape formed by combining an arc portion and a linear portion, and the rotor has a magnetic pole angle of 100 to 120 degrees in electrical angle. A permanent magnet type rotating electric machine wherein a recess is formed between poles on an outer peripheral surface of an iron core. The permanent magnet type rotating electric machine according to claim 1, wherein
A permanent magnet type rotating electric machine characterized in that the concave portion formed between the poles on the outer peripheral surface of the rotor core has a concave shape obtained by combining a plurality of substantially V-shapes. The permanent magnet rotating electric machine according to claim 1,
A permanent magnet type rotating electric machine, wherein a shape of a permanent magnet embedded in the rotor core is a V-shape or a one-character shape protruding with respect to an axis of the rotor. The permanent magnet type rotating electric machine according to any one of claims 1 to 7,
The shape of the concave portion formed between the poles on the outer peripheral surface of the rotor core is longer in the circumferential direction on the outer peripheral side than on the inner peripheral side of the rotor. The permanent magnet type rotating electric machine according to claim 1, wherein
A permanent magnet type rotating electric machine, wherein at least one radially extending slit is provided in a magnetic pole portion of the rotor core. The compressor according to claim 1, wherein the permanent magnet type rotating electric machine is a driving source.

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