CN114465376A

CN114465376A - Motor and rotary compressor

Info

Publication number: CN114465376A
Application number: CN202011474826.3A
Authority: CN
Inventors: 后藤太我; 簗岛俊人; 竹泽正昭; 中山善友
Original assignee: Shenyang Zhonghang Electromechanical Sanyo Refrigeration Equipment Co ltd
Current assignee: Shenyang Zhonghang Electromechanical Sanyo Refrigeration Equipment Co ltd
Priority date: 2020-10-21
Filing date: 2020-12-14
Publication date: 2022-05-10
Anticipated expiration: 2040-12-14
Also published as: CN114465376B; JP2022067776A

Abstract

The purpose of the present invention is to provide an electric motor capable of suppressing a reduction in induced voltage and further reducing the distortion rate of the induced voltage by matching the shape of the tooth inner end surface of a stator to the shape of the rotor outer peripheral surface on which a notch portion is formed. Another object is to provide a rotary compressor including the motor. In order to solve the above-described problems, the present invention provides an electric motor including a rotor and a stator including teeth provided on an outer side of the rotor, wherein a first notch portion, which is deeply cut along with the first notch portion facing a positive side in a rotational direction of the rotor, is formed on an outer peripheral surface of the rotor, and a second notch portion, which is deeply cut along with the second notch portion facing the positive side in the rotational direction, is formed on an inner end of the teeth on the positive side in the rotational direction.

Description

Motor and rotary compressor

Technical Field

The present invention relates to a motor and a rotary compressor.

Background

Currently, as a compressor used for, for example, an air conditioner, a rotary compressor has been provided. The rotary compressor includes a motor having a stator, a rotor, and a rotating shaft (crankshaft) of the rotor, and a rotary compression mechanism connected to the motor via the rotating shaft and driven by operation of the motor.

As the motor, a dc motor is exemplified. In a dc motor, a drive magnetic field generated by an alternating current applied to a coil of a stator rotates a rotor to obtain a rotational torque. On the other hand, when the rotor of the dc motor rotates at a high speed, a large magnetic attraction/repulsion force (hereinafter, simply referred to as "attraction") is generated on the radial side of the stator. As a result, the stator and the hermetic container accommodating the stator vibrate largely, and noise is generated from the rotary compressor. A technique for solving the technical problem in a rotary compressor using such a dc motor is disclosed in, for example, patent document 1 below.

Documents of the prior art

Patent document

Patent document 1: japanese laid-open patent publication No. 2020 and 80632

Disclosure of Invention

Technical problem to be solved by the invention

The technique disclosed in patent document 1 relates to an inner rotor type dc motor including a rotor in which magnetic poles including permanent magnets are arranged at predetermined intervals in a circumferential direction inside a stator, that is, a dc motor in which an outer peripheral surface of each magnetic pole of the rotor has a notch portion cut out in an arc-shaped cross section so as to gradually become deeper toward a positive side in a rotational direction of the rotor. By providing the notch portion of the above shape on the outer peripheral surface of the rotor, a sharp change in magnetic flux density in a gap (clearance) between the rotor and the stator is alleviated, and an attractive force acting on the stator is reduced. Thus, noise generated when the DC motor is operated can be suppressed.

However, an induced voltage is generated in the coil of the stator as the rotor of the dc motor rotates. When the rotor rotates at a constant speed, the induced voltage generated in one coil changes, for example, in a sine wave shape with a predetermined frequency. However, it has been confirmed that when a rotor including the cutout portion of the above-described shape is used like the dc motor of patent document 1, a large amount of harmonic components remain despite a reduced distortion rate of the induced voltage compared to a normal rotor without the cutout portion. The harmonic component remains in the induced voltage, and there is a possibility that controllability of the current applied to the coil by the inverter and the motor output efficiency are lowered.

One of the main causes of the harmonic component remaining in the induced voltage is that, as compared with a dc motor including a normal rotor, the shape of the tooth tip surface (inner end surface) of the stator facing the outer peripheral surface of the rotor does not correspond to the shape of the outer peripheral surface of the rotor (the shape in which the notch portion is provided) contributing to a reduction in the suction force acting on the stator and the distortion rate of the induced voltage.

The present invention has been made in view of the above-described problems, and an object of the present invention is to provide an electric motor capable of further reducing the distortion rate of an induced voltage by matching the shape of the inner end surface of the teeth of a stator with the shape of the outer peripheral surface of a rotor on which a notch portion is formed. Another object is to provide a rotary compressor including the motor.

Technical scheme for solving technical problem

The present invention provides a motor, which is provided with: a rotor; and a stator including a tooth provided on an outer side of the rotor, a first notch portion deeply cut toward a positive side in a rotation direction of the rotor being formed on an outer peripheral surface of the rotor, and a second notch portion deeply cut toward the positive side in the rotation direction being formed on an inner end of the tooth on the positive side in the rotation direction.

According to this aspect of the present invention, since the first notch portion that is deep-cut toward the positive side in the rotational direction of the rotor is formed in the outer peripheral surface of the rotor, and the second notch portion that is deep-cut toward the positive side in the rotational direction is formed at the inner end of the tooth on the positive side in the rotational direction, it is possible to further reduce the distortion rate of the induced voltage generated in the coil of the stator when the rotor rotates.

Here, the distortion rate of the induced voltage is a fundamental component (effective value: V)₁) And each harmonic component (effective value: v₂、V₃…V_n) A value obtained by separating the waveform of the induced voltage obtained from the change in the rotor rotation angle and calculating the following equation using these effective values.

Mathematical formula 1

As a method of separating the fundamental component and each harmonic component from the waveform of the induced voltage, for example, a method of reducing the waveform of the measured induced voltage by Fast Fourier Transform (FFT) and separating the fundamental component from each frequency component corresponding to the other harmonic components is given. However, it is not limited thereto.

In the motor according to the present invention, it is more preferable that the teeth include a main body and a wide portion provided on an inner end side of the main body, the wide portion includes a first extending end portion extending toward the positive side in the rotation direction and a second extending end portion extending toward the opposite side in the rotation direction, the inner end corresponds to an inner end of the first extending end portion, and the condition of the following expression 1 is satisfied:

(formula 1) 0.1-0.9 of A/A' and 0.1-0.7 of B/B%

Formula 1 is a dimension in the depth direction of the second notch portion, formula 1 is a dimension in the depth direction of the first extending end portion when the second notch portion is not supposed to be provided, formula 1 is a dimension in the rotation direction of the second notch portion, and formula 1 is a dimension from the inner end of the first extending end portion to the center of the inner end of the wide portion when the second notch portion is not supposed to be provided, because this can reduce the distortion rate of the induced voltage.

Further, the motor of the present invention satisfies the condition of the following formula 2:

(formula 2) 0.4-0.6 of A/A 'and 0.3-0.7 of B/B'.

In the motor according to the present invention, it is preferable that the rotor is provided with a plurality of magnetic poles, and an outer end of each magnetic pole along an outer peripheral surface of the rotor includes, in a plan view, a first outer end portion forming an arc centered on a rotation center of the rotor and a second outer end portion forming an arc centered on a position spaced a predetermined distance radially outward from the center of the first arc, and the second outer end portion is disposed on a side of the first outer end portion in the rotation direction.

Further, in the motor of the present invention, it is preferable that a relationship between R1 and R2 satisfies a condition of the following expression 3, where the diameter of the arc corresponding to the first outer end portion is R1, and the diameter of the arc corresponding to the second outer end portion is R2:

(formula 3) 2-R2/(R1-R2) -5

Since this can further reduce the distortion rate of the induced voltage.

The rotary compressor of the present invention is provided with the motor.

According to this aspect of the present invention, it is possible to provide a rotary compressor including a motor capable of further reducing a distortion rate of an induced voltage generated in a coil of a stator when a rotor rotates.

Effects of the invention

According to the present invention, the distortion rate of the induced voltage can be further reduced by matching the shape of the inner end face of the teeth of the stator with the shape of the outer peripheral surface of the rotor on which the notch portion is formed. In addition, it is possible to provide a rotary compressor including a motor in which the distortion rate of the induced voltage is further reduced.

Drawings

Fig. 1 is a vertical sectional view of a rotary compressor according to the present embodiment.

Fig. 2 is a horizontal sectional view of the motor of the present embodiment.

Fig. 3 is a horizontal cross-sectional view of the rotor of the motor of the present embodiment.

Fig. 4 is an enlarged view of the inner end of the tooth in a horizontal sectional view of the motor shown in fig. 2.

Fig. 5 is an enlarged view of the inner end of the tooth in a horizontal sectional view of the motor shown in fig. 2.

Fig. 6(a) is a graph showing the transition of the induced voltage distortion rate when the cutting level of the first notch portion is changed, and fig. 6(b) is a graph showing the transition of the induced voltage when the cutting level of the first notch portion is changed.

Fig. 7 is an enlarged view showing the structures of the tooth inner ends and the rotor outer ends in example 1 and comparative examples 1 to 3.

Fig. 8 is a graph showing waveforms of induced voltages in example 1 and comparative examples 1 to 3.

Fig. 9 is a graph showing changes in the attraction force acting on the inner ends of the teeth when the rotor is rotated.

Description of the reference numerals

1: a rotary compressor; 10: an electric motor; 11: a stator; 110: a stator core; 111: a yoke; 112: teeth; 112 a: a body portion of the tooth; 112 b: a wide portion of the tooth; 112 c: an extension end portion provided on the rotation direction positive side; 112c 1: a second notch portion; 112 d: an extension end portion provided on the opposite side of the rotation direction; 12: a rotor; 121: a rotor core; 121 b: a first notch portion; 122: a permanent magnet; 123: a magnetic pole; 13: a rotating shaft of the rotor; 20: a rotary compression mechanism part; 21: a cylinder; 211: a compression chamber; 22: a deflection core portion; 23: a roller; 24: a blade; 30: a container.

Detailed Description

A rotary compressor according to an embodiment of the present invention will be described in detail below with reference to the accompanying drawings. First, the overall structure of the rotary compressor 1 according to one embodiment of the present invention will be described with reference to fig. 1. Here, fig. 1 is a vertical sectional view of the rotary compressor 1.

As shown in fig. 1, the rotary compressor 1 of the present embodiment includes a motor 10 and a rotary compression mechanism 20 driven by the motor 10. The motor 10 and the rotary compression mechanism 20 are housed in a steel plate-made closed casing 30 including a casing body portion 31 and a lid portion 32. The rotary compressor 1 shown in the drawings is a vertical type, but is not limited thereto. The rotary compressor of the present invention may be applied to a horizontal type rotary compressor.

The motor 10 is a brushless dc motor including a stator 11, a rotor 12, and a rotating shaft (crankshaft) 13 of the rotor 12. Here, the stator 11 includes a stator core 110 in which a plurality of electromagnetic steel plates having a substantially cylindrical airspace formed therein and a circular ring shape in a plan view are stacked in a height direction. The stator core 110 includes a cylindrical yoke 111 and a plurality of teeth 112 extending radially inward from the inner periphery of the yoke 111. The coil 113 is wound around each tooth 112 in a concentrated winding manner. Further, details of the stator core 110 will be described later with reference to fig. 2 and the like.

The coil 113 is electrically connected to the terminal 33 mounted on the lid 32 of the container 30. When power is supplied to the coil 113 from the terminal 33, current flows through the coil 113. Thereby, a rotating magnetic field acting on the rotor 12 is generated, and the rotor 12 rotates.

The rotor 12 includes a rotor core 121 formed by stacking a plurality of electromagnetic steel plates having a substantially circular shape in plan view in the height direction, and a permanent magnet 122 provided in the rotor core 121. The rotor core 121 is disposed in a cylindrical hollow formed inside the stator 11. At this time, a minute gap (clearance) is formed between the inner ends of the teeth 112 of the stator 11 and the outer peripheral surface of the rotor core 121. A through hole 12b penetrating in the height direction is formed in the center of the rotor core 121. The rotary shaft 13 is inserted into the through hole 12b and supports the rotor 12.

Next, as shown in fig. 1, the rotary compression mechanism 20 includes a cylinder 21, an eccentric portion 22, a roller 23, a vane 24, and the like. Here, as shown in fig. 1, the cylinder 21 includes a compression chamber 211 penetrating vertically therein. The eccentric portion 22 is accommodated in the compression chamber 211 and is formed integrally with the rotary shaft 13. Further, a roller 23 is provided around the outer side surface of the eccentric portion 22. Moreover, frames 26a and 26b including bearing portions for the rotary shaft 13 are attached to the upper side and the lower side of the cylinder 21, respectively.

In the rotary compression mechanism 20 having the above-described configuration, when the rotary shaft 13 rotates, the eccentric portion 22 and the rotor 23 eccentrically rotate in the compression chamber 211. At this time, the rotor 23 eccentrically rotates along the inner surface of the compression chamber 211. Further, the vane 24 abutting against the outer surface of the rotor 23 is inserted outside the cylinder 21 in accordance with the eccentric rotation of the rotor 23. If the rotor 23 continues to rotate eccentrically, the vane 24 slides in the opposite direction to the previous direction by the action of the spring that biases the vane 24, and returns to the original position.

The refrigerant supplied from the accumulator 70 to the compression chamber 211 through the refrigerant suction passage 27 formed in the cylinder 21 is compressed by the above-described operation of the eccentric portion 22, the roller 23, and the vane 24. The compressed refrigerant is discharged to the container 30 through a flow path (not shown) in the housing 26 a.

The rotary compression mechanism 20 shown in the figure includes two cylinders 21, but the number of cylinders is not limited to this. That is, the rotary compression mechanism 20 may include one cylinder 21, or may include two or more cylinders 21.

Next, details of the motor 10 according to the present embodiment will be described with reference to fig. 2 to 5. Here, fig. 2 is a horizontal sectional view of the motor 10. Fig. 3 is a horizontal sectional view of the rotor 12. Fig. 4 and 5 are enlarged views of the inner ends of the teeth 112 in the horizontal cross-sectional view of the motor 10 shown in fig. 2. The illustrated motor 10 has a number of poles of 6 poles and 9 slots and a slot, but is not limited thereto.

As shown in fig. 2, the teeth 112 of the stator core 110 each include a body portion 112a extending radially inward from the inner periphery of the yoke 111 and a wide portion 112b provided on the tip end side (radially inner end side) of the body portion 112 a. The wide portion 112b includes a first extending end portion 112c and a second extending end portion 112d that extend on the positive side and the negative side in the rotation direction of the rotor 12 indicated by the arrow a. However, the teeth 112 may have a substantially uniform width up to the tip (that is, the teeth 112 may not have the wide width portion 112 b).

Next, as shown in fig. 3, the plurality of permanent magnets 122 in the rotor 12 are arranged in a circumferential direction. In the present embodiment, each permanent magnet 122 is fitted into a slit provided at a predetermined portion of the rotor core 121. The type of the permanent magnet 122 is not particularly limited, and examples thereof include ferrite magnets, neodymium magnets, samarium-cobalt magnets, and praseodymium magnets.

The permanent magnet 122 of the present embodiment has a set of three

magnets

122a, 122b, 122c arranged in series. Further, a magnetic pole 123 is formed by a region including the permanent magnet 122 and the outer peripheral surface 121a of the rotor core 121 opposed to the magnet 122 a. In the case of the mode shown in fig. 3, six magnetic poles are formed. The outer peripheral surface 121a corresponds to the outer end of the magnetic pole 123.

The outer end (outer circumferential surface 121a) of the magnetic pole 123 of the present embodiment includes, in a plan view (a horizontal cross-sectional view of the rotor 12 shown in fig. 3), a first outer end 121a1 forming an arc centered on the rotation center O1 of the rotor 12 and a second outer end 121a2 forming an arc centered on a position O2 radially outward from the center of the first arc by a predetermined distance. The second outer end portion 121a2 is disposed on the rotation direction positive side of the first outer end portion 121a 1. Thereby, the first notch 121b is formed to be deep cut toward the positive side in the rotation direction of the rotor 12.

However, the larger the amount of gap (cut amount), the more the magnetic resistance between the stator and the rotor increases, and the more the magnetic flux linked with the coil 113 decreases. Therefore, the induced voltage generated in the coil 113 decreases. Therefore, it is preferable to adjust the cutting amount by focusing not only on the distortion rate of the induced voltage but also on the decrease in the induced voltage. Here, in order to reduce the distortion rate of the induced voltage while suppressing the reduction of the induced voltage, it is preferable that the relationship between R1 and R2 satisfies the following condition when the diameter of the arc corresponding to the first outer end portion 121a1 (the size of the line segment connecting the rotation center O1 and the first outer end portion 121a 1) is R1 and the diameter of the arc corresponding to the second outer end portion 121a2 (the size of the line segment connecting the center O2 and the second outer end portion 121a2) is R2:

(formula) 2 is less than or equal to R2/(R1-R2) is less than or equal to 5.

Further, by satisfying the following expression of the relationship between R1 and R2, the effect of further reducing the distortion rate of the induced voltage is achieved while suppressing the decrease in the induced voltage.

(formula) 2-R2/(R1-R2) -3

Next, the structure of the stator core 110 on the inner end side of the teeth 112 will be described in detail with reference to fig. 4 and 5. A wide portion 112b having a first extending end portion 112c and a second extending end portion 112d is provided at an inner end of the tooth 112. Further, a second notch portion 112c1, which is deeply cut toward the positive side in the rotation direction, is formed at the inner end of the first extending end portion 112c extending toward the positive side in the rotation direction of the rotor 12.

By arranging the first notch 121b and the second notch 112c1 substantially symmetrically with respect to the gap between the outer end 121a of the rotor 12 and the inner end (wide portion 112b) of the tooth 112, the distortion rate of the induced voltage can be further reduced. The end edge 112e of the second cutout portion 112c1 is not particularly limited, but is preferably linear or curved in plan view.

Here, as shown in fig. 5, assuming that a dimension of the second notch portion 112c1 in the depth direction is a, a dimension of the first extension end portion 112c in the depth direction when the second notch portion 112c1 is not provided is a ', a dimension of the second notch portion 112c1 in the width direction (rotation direction) is B, and a dimension from the inner end (reference numeral 112c2 in fig. 5) of the first extension end portion 112c to the center (reference numeral 112c3 in fig. 5) of the inner end of the wide portion when the second notch portion 112c1 is not provided is B', the relationship of A, A 'and B, B' is adjusted so as to satisfy the following condition. This can further reduce the distortion rate of the induced voltage while suppressing a decrease in the induced voltage.

(formula) 0.1-0.9 of A/A' and 0.1-0.7 of B/B%

The relationship between A, A 'and B, B' is adjusted so as to satisfy the following expression. This can further reduce the distortion rate of the induced voltage while suppressing a decrease in the induced voltage.

(formula) 0.4-0.6 of A/A' and 0.3-0.7 of B/B%

Examples

The following description relates to the above-described specific embodiment of the rotary compressor 1 and the motor 10. However, the present invention is not limited to the following examples.

[ relationship between the cutting level of the first notch portion, the distortion rate of the induced voltage, and the induced voltage ]

In the present embodiment, the index of the cut amount of the first notch portion 121b (the cut amount of the outer end 121a of the magnetic pole 123) is represented by [ R2/(R1-R2) ] using the diameter R1 of the circular arc corresponding to the first outer end portion 121a1 of the rotor 12 and the diameter R2 of the circular arc corresponding to the second outer end portion 121a 2. Hereinafter, this index is referred to as "cutting level". The smaller the value of [ R2/(R1-R2) ] the greater the cutting level (the outer end 121a of the rotor 12 is deeply cut). On the other hand, the more the value of [ R2/(R1-R2) ] increases, the smaller the cutting level (the outer end 121a of the rotor 12 is shallowly cut).

Fig. 6(a) shows the distortion rate of the induced voltage when the cleavage level [ R2/(R1-R2) ] is changed. The horizontal axis of FIG. 6 represents the cutting level [ R2/(R1-R2) ]. In addition, the vertical axis of fig. 6(a) represents the distortion rate of the induced voltage. Here, the distortion rate of the induced voltage shown in the vertical axis of fig. 6 represents a ratio (%) to the distortion rate of the induced voltage in the motor 10 in which the notch on the rotor 12 side (the first notch portion 121b) and the notch on the stator 11 side (the second notch portion 112c1) are not formed. Fig. 6(b) shows the induced voltage when the cut level [ R2/(R1-R2) ] is changed. The horizontal axis of FIG. 6(b) represents the cutting level [ R2/(R1-R2) ]. In addition, the vertical axis of fig. 6(b) represents the induced voltage. Here, the induced voltage shown in the vertical axis of fig. 6(b) represents a ratio (%) to the induced voltage in the motor 10 in which the notch on the rotor 12 side (first notch 121b) and the notch on the stator 11 side (second notch 112c1) are not formed.

As shown in fig. 6(a), when the cleavage level is decreased from [ R2/(R1-R2) ] -1 (the value of [ R2/(R1-R2) ] is increased), [ R2/(R1-R2) ] -2, and the distortion rate of the induced voltage reaches the minimum value. When the cutting level is further reduced, the distortion rate of the induced voltage increases with a decrease in the cutting level ([ R2/(R1-R2) ] an increase in the value. On the other hand, as shown in fig. 6(b), the induced voltage increases with a decrease in the cleavage level from [ R2/(R1-R2) ], 1 (an increase in the value of [ R2/(R1-R2) ].

From the results shown in FIGS. 6(a) and 6(b), it was confirmed that the distortion rate of the induced voltage can be greatly reduced while suppressing the decrease in the induced voltage in the range of 2. ltoreq.R 2/(R1-R2). ltoreq.5, particularly 2. ltoreq.R 2/(R1-R2). ltoreq.3. In more detail, in the case where [ R2/(R1-R2) ] is less than 2 (for example, in the case of 1.5), the distortion rate of the induced voltage is reduced to some extent, and the induced voltage is greatly reduced (for example, compared with the case where [ R2/(R1-R2) ], which is 2.5). On the other hand, when [ R2/(R1-R2) ] -5, the induced voltage is higher and the distortion rate of the induced voltage is maintained at a value higher by about 10% than that in the case of [ R2/(R1-R2) ] -2, which is the minimum distortion rate of the induced voltage. On the other hand, when [ R2/(R1-R2) ] is higher than 5, the distortion rate of the induced voltage further increases. Therefore, as a range to achieve the effect of reducing the induced voltage distortion rate while suppressing the induced voltage decrease, it is desirable that 2. ltoreq. R2/(R1-R2). ltoreq.5. Further, the distortion rate of the induced voltage at each cutting level corresponds to the minimum value of values obtained by variously changing the cutting rate [ a/a '] (a and a' are as described above) on the depth direction side of the second notched portion 112c1 in the tooth 112 of the stator 11 and the cutting rate [ B/B '] (B and B' are as described above) on the rotation direction side of the second notched portion 112c 1. In addition, the induced voltage at each cutting level corresponds to the maximum value of values obtained by variously changing the cutting rate [ a/a '] and the cutting rate [ B/B' ].

[ relationship between the cutting Rate of the second notched portion and the distortion Rate of the induced Voltage ]

Next, in the second notch 112c1 formed at the inner end of the tooth 112, the distortion rates of the induced voltage when the depth-side cut rate [ a/a '] and the rotation-side cut rate [ B/B' ] are changed are shown in tables 1 to 3 below. In addition, the induced voltages when the cleavage efficiencies [ A/A '] and [ B/B' ] were changed are shown in tables 4 to 6 below. The distortion rate and the value of the induced voltage shown in tables 1 to 6 correspond to the distortion rate and the ratio (%) of the induced voltage measured in the motor 10 in which the first notch 121b and the second notch 112c1 are not formed, as in the case shown in fig. 6. The cutting level of the first notch 121b [ R2/(R1-R2) ] is shown in each table.

TABLE 1

TABLE 2

TABLE 3

TABLE 4

TABLE 5

TABLE 6

As shown in tables 1 to 6, as the range in which the effect of reducing the induced voltage distortion rate is achieved while suppressing the decrease in the induced voltage, it is preferable that the cutting rate [ A/A '] on the depth direction side and the cutting rate [ B/B' ] on the rotation direction side satisfy the condition of [ 0.1. ltoreq. A/A '. ltoreq.0.9 and 0.1. ltoreq. B/B'. ltoreq.0.7 ]. On the other hand, particularly when [ B/B' ] is higher than 0.7, the induced voltage is not preferable because the induced voltage has a low distortion rate in addition to a high induced voltage. In addition, as a range in which the effect of further reducing the induced voltage distortion rate is achieved while suppressing the reduction in the induced voltage, a range satisfying the condition of the following expression is desirable.

(formula) 0.4-0.6 of A/A' and 0.3-0.7 of B/B%

[ relationship between the formation site of the notch and the distortion rate of the induced voltage ]

Next, using example 1 and comparative examples 1 to 3 (see fig. 7), the relationship between the formation site of the notch portion (the first notch portion 121b, the second notch portion 112c1) and the distortion rate of the induced voltage was confirmed. Fig. 8 shows waveforms of induced voltages in example 1 and comparative examples 1 to 3 when the rotor 12 is rotated. Here, the ordinate of fig. 8 corresponds to a ratio (%) where the amplitude of the fundamental wave of the induced voltage of comparative example 3 is 100%. In example 1, [ R2/(R1-R2) ] -2, [ a/a '] 0.5, and [ B/B' ] 0.7.

In example 1 shown in fig. 7 a, the first notch 121a is provided on the positive side in the rotation direction (second outer end portion 121a2) of the outer end of the magnetic pole 123 of the rotor 12, and the second notch 112c1 is provided on the positive side in the rotation direction (first extending end portion 112c) of the inner end of the tooth 112. In contrast, comparative example 1 shown in fig. 7(b) is different from example 1 in that the opposite side (second extending end portion 112d) to the rotation direction of the inner end of the tooth 112 is also provided with a notched portion. Otherwise, the same as in example 1 was applied. Further, comparative example 2 shown in fig. 7(c) is different from example 1 in that no notch portion is formed at the inner end of the tooth 112. Otherwise, the same as in example 1 was applied. In comparative example 3 shown in fig. 7(d), no notch portion is formed at both the outer end of the magnetic pole 123 of the rotor 12 and the inner end of the tooth 112.

As shown in fig. 8, in example 1, an induced voltage close to a sine wave waveform was measured. That is, as the waveform representing the induced voltage, a waveform with less harmonic components other than the fundamental wave component is obtained. In contrast, in comparative examples 1 to 3, waveforms including many irregularities were obtained with respect to sine wave waveforms. Thus, it is shown that comparative examples 1 to 3 include many harmonic components other than the fundamental component, as compared with embodiment 1.

The distortion rate of the induced voltage (ratio (%) to comparative example 3) of example 1, comparative example 1 to comparative example 3 is shown in table 7 below. As shown in table 7, the distortion rate of the induced voltage of example 1 was greatly reduced as compared with comparative examples 1 to 3. That is, it was confirmed that the distortion rate of the induced voltage can be greatly reduced by providing the first notch 121b on the rotor 12 side and the second notch 112c1 on the tooth 112 side substantially symmetrically with a gap therebetween as in example 1.

Table 7 units: is based on

	Example 1	Comparative example 1	Comparative example 2	Comparative example 3
					Distortion rate of induced voltage	29	43	54	100

[ comparison of attraction forces acting on the inner ends of teeth ]

Fig. 9(a) is a graph showing changes in the suction force acting on the tooth inner ends when the rotor 12 is rotated in example 1 and comparative examples 1 to 3. Here, the vertical axis in fig. 9(a) corresponds to a ratio (%) where the amplitude of the suction force of comparative example 3 is 100%. In addition, the waveform of comparative example 3 was shifted so that the center of the amplitude thereof was 0. Fig. 9(b) is an enlarged view of the stator 11 (teeth 112) including positive and negative arrows indicating the attraction force. Here, the arrow tip side shown in fig. 9(b) corresponds to the positive side (positive side) of the attractive force, and the arrow base side corresponds to the negative side (negative side) of the attractive force.

As shown in fig. 9(a), the suction force acting on the teeth 112 is reduced in example 1 as compared with comparative examples 1 and 3. That is, as in example 1, it was confirmed that by providing the first notch 121b on the rotor 12 side and the second notch 112c1 on the tooth 112 side substantially symmetrically with a gap therebetween, the suction force acting on the inner end surface of the tooth 112 can be reduced, and vibration of the motor 10 and noise from the rotary compressor 1 can be suppressed.

The embodiments of the present invention are explained in detail. However, the above description is for the purpose of facilitating understanding of the present invention, and is not intended to limit the present invention. The present invention may include embodiments modified or improved from the above-described embodiments without departing from the gist thereof. Further, equivalents thereof are included in the present invention.

Industrial applicability

The rotary compressor of the present invention is used for example in household/commercial air conditioners and the like. However, the use thereof is not limited thereto.

Drawings

FIG. 5(a)

Center (C)

FIG. 5(b)

Depth direction

Rotation direction (width direction)

FIG. 6(a)

Induced voltage distortion rate [% ]

FIG. 6(b)

Induced voltage [% ]

FIG. 8(a)

Induced voltage [% ]

Rotor rotation angle [ deg ]

FIG. 8(b)

Induced voltage [% ]

Rotor rotation angle [ deg ]

FIG. 8(c)

Induced voltage [% ]

Rotor rotation angle [ deg ]

FIG. 8(d)

Induced voltage [% ]

Rotor rotation angle [ deg ]

FIG. 9

Attraction force [% ]

Rotor rotation angle [ deg ]

Example 1

Comparative example 1

Comparative example 2

Comparative example 3.

Claims

1. An electric motor, comprising:

a rotor;

a stator including teeth disposed outside the rotor,

a first notch part deeply cut toward the positive side of the rotation direction of the rotor is formed on the outer peripheral surface of the rotor,

a second notch portion that is deeply cut toward the rotation direction positive side is formed at an inner end of the tooth on the rotation direction positive side.

2. The motor according to claim 1, wherein,

the tooth includes a main body portion and a wide portion provided on an inner end side of the main body portion,

the wide width portion includes a first extending end portion extending toward the rotation direction positive side and a second extending end portion extending toward the rotation direction reverse side,

the inner end corresponds to an inner end of the first extension end,

further, the condition of the following formula 1 is satisfied:

(formula 1) 0.1-0.9 of A/A' and 0.1-0.7 of B/B%

A in formula 1 is a dimension in the depth direction of the second notch portion,

a' in formula 1 is a dimension in the depth direction of the first extending end portion on the assumption that the second notch portion is not provided,

b in formula 1 is a dimension in the rotation direction of the second notch portion,

b' in formula 1 is a dimension from the inner end of the first extending end portion to the center of the inner end of the wide width portion on the assumption that the second notch portion is not provided.

3. The motor according to claim 2, wherein,

satisfying the condition of the following formula 2:

(formula 2) 0.4-0.6 of A/A 'and 0.3-0.7 of B/B'.

4. The motor according to any one of claims 1 to 3,

a plurality of magnetic poles are arranged on the rotor,

in a plan view, the outer end of each magnetic pole along the outer peripheral surface of the rotor includes a first outer end portion forming an arc centered on the rotation center of the rotor and a second outer end portion forming an arc centered on a position radially outward from the rotation center by a predetermined distance,

the second outer end portion is disposed on the rotation direction positive side of the first outer end portion.

5. The motor according to claim 4, wherein,

a relationship of R1 and R2 satisfies a condition of the following formula 3, assuming that the diameter of the circular arc corresponding to the first outer end portion is R1 and the diameter of the circular arc corresponding to the second outer end portion is R2:

(formula 3)2 is not less than R2/(R1-R2) is not less than 5.

6. A rotary compressor comprising the motor according to any one of claims 1 to 5.