Electric motors and rotary compressors

Abstract

To provide a dynamo-electric motor capable of further reducing a distortion factor of an induction voltage while suppressing reduction of the induction voltage by making the shape of a teeth inner end surface of a stator correspond to the shape of a rotor outer periphery surface on which a notch part is formed, and provide a rotary compressor comprising the dynamo-electric motor.SOLUTION: A dynamo-electric motor comprises: a rotor; and teeth provided on the outer side of the rotor. A first notch part which is notched so as to be deeper as it moves toward a positive side of a rotational direction of the rotor is formed in an outer peripheral surface of the rotor. A second notch part which is notched so as to be deeper as it moves toward the positive side of the rotational direction is formed in an inner side end of the positive side of the rotational direction in the teeth. The present invention also provides a rotary compressor including the dynamo-electric motor.SELECTED DRAWING: Figure 2

Description

[Technical field]

[0001] The present invention relates to an electric motor and a rotary compressor. [Background technology]

[0002] Conventionally, rotary compressors have been provided as compressors for air conditioners, for example. The rotary compressor includes an electric motor including a stator, a rotor, and a rotating shaft (crankshaft) of the rotor, and a rotary compression mechanism that is connected to the electric motor via the rotating shaft and driven by the operation of the electric motor.

[0003] An example of an electric motor is a DC motor. In a DC motor, a driving magnetic field generated by the action of an alternating current applied to a coil of a stator rotates a rotor, and a rotational torque is obtained. On the other hand, when the rotor of a DC motor rotates at high speed, a large magnetic attraction and repulsion force (hereinafter simply referred to as "attraction force") is generated on the radial side of the stator. As a result, the stator and the sealed container that houses the stator vibrate greatly, and noise is generated from the rotary compressor. A technology for solving such problems in a rotary compressor using a DC motor is disclosed, for example, in Patent Document 1 below. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] JP 2020-80632 A Summary of the Invention [Problem to be solved by the invention]

[0005] The technology disclosed in Patent Document 1 relates to an inner rotor type DC motor that includes a rotor inside a stator, in which magnetic poles including permanent magnets are arranged at a predetermined interval in the circumferential direction, and in which the outer peripheral surface of each magnetic pole of the rotor has a cutout cut into an arc-shaped cross section that gradually becomes deeper toward the positive rotational direction of the rotor. By providing a cutout of this shape on the outer peripheral surface of the rotor, a sudden change in magnetic flux density in the air gap between the rotor and the stator is mitigated, and the attractive force acting on the stator is reduced. This makes it possible to suppress noise during operation of the DC motor.

[0006] Incidentally, as the rotor of a DC motor rotates, an induced voltage is generated in the coil of the stator. When the rotor rotates at a constant speed, the induced voltage generated in one coil changes, for example, into a sine wave of a predetermined frequency. However, when a rotor including a notch of the above shape is used as in the DC motor of Patent Document 1, the distortion rate of the induced voltage is reduced compared to a general rotor without a notch, but it has been confirmed that many harmonic components still remain. The fact that harmonic components remain in the induced voltage is undesirable because it may reduce the controllability of the coil current applied by the inverter and the efficiency improvement of the motor output.

[0007] Here, one of the reasons why harmonic components remain in the induced voltage is that, compared to DC motors with a general rotor, the shape of the rotor's outer peripheral surface (the shape with the cutout portion) which contributes to reducing the attraction force acting on the stator and the distortion rate of the induced voltage, does not correspond to the shape of the tip surface (inner end surface) of the stator's teeth which faces the outer peripheral surface of the rotor.

[0008] The present invention has been made in view of the above problems, and aims to provide an electric motor capable of further reducing the distortion rate of the induced voltage by making the shape of the inner end faces of the stator teeth correspond to the shape of the outer circumferential surface of the rotor on which the notches are formed, and also aims to provide a rotary compressor equipped with this electric motor. [Means for solving the problem]

[0009] The electric motor according to the present invention comprises: A rotor; a stator including teeth provided on the outside of the rotor; Equipped with a first cutout portion that is cut deeper toward the positive side in the rotation direction of the rotor is formed on the outer circumferential surface of the rotor; A second cutout portion that is cut deeper toward the positive side in the rotation direction is formed at an inner end of the tooth on the positive side in the rotation direction. 、 The tooth includes a main body portion and a wide portion provided on an inner end side of the main body portion, The wide portion includes a first extending end portion extending in the forward direction of the rotation and a second extending end portion extending in the reverse direction of the rotation, The inner end corresponds to the inner end of the first extending end portion, Furthermore, the condition of the following formula 1 is satisfied. (Formula 1) 0.1≦A / A'≦0.9 and 0.1≦B / B'≦0.7 In formula 1, A is the dimension of the second cutout portion in the depth direction. In formula 1, A' is the dimension in the depth direction of the first extending end portion on the assumption that the second cutout portion is not provided. In formula 1, B is the dimension of the second cutout portion in the rotational direction. In formula 1, B' is the dimension from the inner end of the first extending end portion to the center of the inner end of the wide portion on the assumption that the second cutout portion is not provided.

[0010] According to this aspect of the present invention, a first notch that becomes deeper toward the positive rotational direction of the rotor is formed on the outer peripheral surface of the rotor, and a second notch that becomes deeper toward the positive rotational direction is formed on the inner end of the tooth on the positive rotational direction side, thereby further reducing the distortion of the induced voltage generated in the stator coil when the rotor rotates.

[0011] Here, the distortion rate of the induced voltage is the fundamental wave component (effective value: V1) and each harmonic component (effective values: V2, V3, . . . , V n ) and the effective values ​​are separated and calculated using the following formula:

[0012]

number

[0013] In addition, a method for separating the fundamental wave component and each harmonic component from the waveform of the induced voltage may include, for example, performing a fast Fourier transform (FFT) on the waveform of the measured induced voltage to separate each frequency component corresponding to the fundamental wave component and other harmonic components, but is not limited to this.

[0015] Furthermore, the electric motor according to the present invention satisfies the condition of the following formula 2: This is preferable because it is possible to further reduce the distortion factor of the induced voltage. (Formula 2) 0.4≦A / A'≦0.6 and 0.3≦B / B'≦0.7

[0016] Furthermore, in the electric motor according to the present invention, A rotor is provided with a plurality of magnetic poles, an outer end of each magnetic pole along the outer peripheral surface of the rotor includes, in a plan view, a first outer end portion that forms an arc centered on the rotation center of the rotor, and a second outer end portion that forms an arc centered at a position that is a predetermined distance away radially outward from the center of the first arc; The second outer end portion is disposed on the positive side of the rotation direction relative to the first outer end portion. This is preferable because it is possible to further reduce the distortion factor of the induced voltage.

[0017] Furthermore, in the electric motor according to the present invention, The radius of the arc corresponding to the first outer end is R1, and the radius of the arc corresponding to the second outer end is R2. The relationship between R1 and R2 satisfies the condition of the following formula 3. This is preferable because it is possible to further reduce the distortion factor of the induced voltage. (Formula 3) 2≦R2 / (R1-R2)≦5

[0018] Moreover, a rotary compressor according to the present invention includes the above-mentioned electric motor.

[0019] According to this aspect of the present invention, it is possible to provide a rotary compressor equipped with an electric motor capable of further reducing the distortion factor of the induced voltage generated in the coil of the stator when the rotor rotates. Effect of the Invention

[0020] According to the present invention, the shape of the inner end face of the stator teeth corresponds to the shape of the outer circumferential surface of the rotor on which the notches are formed, thereby further reducing the distortion rate of the induced voltage. Also, a rotary compressor including a motor with a further reduced distortion rate of the induced voltage can be provided. [Brief description of the drawings]

[0021] [Figure 1] FIG. 2 is a vertical sectional view of the rotary compressor according to the embodiment. [Diagram 2] FIG. 2 is a horizontal cross-sectional view of the electric motor according to the embodiment. [Diagram 3] FIG. 2 is a horizontal cross-sectional view of a rotor in the electric motor of the present embodiment. [Figure 4] 3 is an enlarged view of inner ends of teeth in a horizontal cross-sectional view of the electric motor shown in FIG. 2. [Diagram 5] 3 is an enlarged view of inner ends of teeth in a horizontal cross-sectional view of the electric motor shown in FIG. 2. [Figure 6] 1A is a graph showing the change in induced voltage distortion rate when the cut level of the first notch is changed, and FIG. 1B is a graph showing the change in induced voltage when the cut level of the first notch is changed. [Figure 7] 4 is an enlarged view showing the structures of inner ends of teeth and outer ends of rotors in Example 1 and Comparative Examples 1 to 3. FIG. [Figure 8] 4 is a graph showing waveforms of induced voltages in Example 1 and Comparative Examples 1 to 3. [Figure 9] 5 is a graph showing changes in attractive force acting on the inner ends of the teeth when the rotor is rotated. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0022] Hereinafter, a rotary compressor according to an embodiment of the present invention will be described in detail with reference to the drawings. First, the overall configuration of a rotary compressor 1 according to an 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.

[0023] As shown in Fig. 1, the rotary compressor 1 according to this embodiment includes an electric motor 10 and a rotary compression mechanism 20 driven by the electric motor 10. The electric motor 10 and the rotary compression mechanism 20 are housed in a sealed container 30 made of a steel plate and including a container body 31 and a lid 32. The illustrated rotary compressor 1 is of a vertical type, but is not limited to this. The rotary compressor according to the present invention can also be applied to a horizontal type rotary compressor.

[0024] The electric 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, each having a doughnut shape in plan view and with a substantially cylindrical air space formed inside, are stacked in the height direction. The stator core 110 includes a cylindrical yoke 111 and a plurality of teeth 112 extending radially inward from the inner circumference of the yoke 111. The coils 113 are wound around each of the teeth 112 by a concentrated winding method. Details of the stator core 110 will be described later with reference to FIG. 2 etc.

[0025] The coil 113 is electrically connected to a terminal 33 attached to the lid 32 of the container 30. When power is supplied from the terminal 33 to the coil 113, a current flows through the coil 113. This generates a rotating magnetic field that acts on the rotor 12, causing the rotor 12 to rotate.

[0026] The rotor 12 includes a rotor core 121 formed by stacking a plurality of electromagnetic steel plates, each of which has a generally 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 air space formed inside the stator 11. At this time, a small gap (air gap) is formed between the inner ends of the teeth 112 of the stator 11 and the outer circumferential surface of the rotor core 121. Furthermore, a through hole 12b is formed in the center of the rotor core 121, penetrating it in the height direction. The rotating shaft 13 is inserted into the through hole 12b to support the rotor 12.

[0027] Next, as shown in Fig. 1, the rotary compression mechanism 20 includes a cylinder 21, an eccentric portion 22, rollers 23, vanes 24, etc. Here, as shown in Fig. 1, the cylinder 21 includes an internal compression chamber 211 that penetrates vertically. The eccentric portion 22 is housed within the compression chamber 211, and is integrally formed with the rotating shaft 13. Furthermore, the rollers 23 are provided around the outer surface of the eccentric portion 22. Furthermore, frame bodies 26a, 26b including bearing portions for the rotating shaft 13 are attached to the upper and lower sides of the cylinder 21, respectively.

[0028] In the rotary compression mechanism 20 having the above-mentioned structure, when the rotary shaft 13 rotates, the eccentric portion 22 and the rotor 23 move in the compression chamber 211. La At this time, the rotor 23 rotates eccentrically. La 23 rotates eccentrically along the inner surface of the compression chamber 211. La Due to the eccentric rotation of 23, La The vane 24 abutting the outer surface of the cylinder 21 is pushed outward. La As the vane 23 continues to rotate eccentrically, the vane 24 slides in the opposite direction due to the action of the spring biasing the vane 24, and returns to its original position.

[0029] 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-mentioned operations of the eccentric portion 22, the roller 23, and the vane 24. In addition, the compressed refrigerant is discharged toward the container 30 through a flow path (not shown) in the frame 26a.

[0030] Although the illustrated rotary compression mechanism 20 includes two cylinders 21, 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.

[0031] Next, the electric motor 10 of this embodiment will be described in detail with reference to Fig. 2 to Fig. 5. Fig. 2 is a horizontal cross-sectional view of the electric motor 10. Fig. 3 is a horizontal cross-sectional view of the rotor 12. Figs. 4 and 5 are enlarged views of inner ends of teeth 112 in the horizontal cross-sectional view of the electric motor 10 shown in Fig. 2. The electric motor 10 shown in the figures has six poles and nine slots, but is not limited to this number of poles and slots.

[0032] 2, each of the teeth 112 of the stator core 110 includes a main body portion 112a extending radially inward from the inner circumference of the yoke 111, and a wide portion 112b provided on the tip side (radially inner end side) of the main body portion 112a. Furthermore, the wide portion 112b includes a first extending end portion 112c and a second extending end portion 112d extending respectively to the forward and reverse sides of 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 (i.e., the teeth 112 do not necessarily have to include the wide portion 112b).

[0033] 3, the multiple permanent magnets 122 in the rotor 12 are arranged in a line in the circumferential direction. In this embodiment, each permanent magnet 122 is fitted into a slot provided at a predetermined position in the rotor core 121. The type of permanent magnet 122 is not particularly limited, and examples include ferrite magnets, neodymium magnets, samarium-cobalt magnets, and praseodymium magnets.

[0034] In this embodiment, the permanent magnet 122 has a set of three magnets 122a, 122b, and 122c arranged in series. A magnetic pole 123 is formed by an area including the permanent magnet 122 and the outer peripheral surface 121a of the rotor core 121 facing the magnet 122a. In the case of the embodiment shown in FIG. 3, six magnetic poles are formed. The outer peripheral surface 121a corresponds to the outer end of the magnetic pole 123.

[0035] In addition, in a plan view (horizontal cross-sectional view of the rotor 12 shown in FIG. 3), the outer end (outer peripheral surface 121a) of the magnetic pole 123 in this embodiment includes a first outer end 121a1 that forms an arc centered on the rotation center O1 of the rotor 12, and a second outer end 121a2 that forms an arc centered on a position O2 that is a predetermined distance away radially outward from the center of the first arc. Furthermore, the second outer end 121a2 is disposed on the positive rotation direction side of the first outer end 121a1. This forms a first cutout portion 121b that is cut deeper toward the positive rotation direction side of the rotor 12.

[0036] Incidentally, the larger the cut amount is, the greater the magnetic resistance between the stator and the rotor is, and the smaller the magnetic flux interlinked with the coil 113 is. Therefore, the induced voltage generated in the coil 113 is lower. For this reason, it is preferable to adjust the cut amount by paying attention not only to the distortion rate of the induced voltage but also to the reduction in the induced voltage. Here, when the diameter of the arc corresponding to the first outer end 121a1 (the dimension of the line segment connecting the rotation center O1 and the first outer end 121a1) is R1 and the diameter of the arc corresponding to the second outer end 121a2 (the dimension of the line segment connecting the center O2 and the second outer end 121a2) is R2, it is preferable that the relationship between R1 and R2 satisfies the condition of the following formula, in order to reduce the distortion rate of the induced voltage while suppressing the reduction in the induced voltage. (Formula) 2≦R2 / (R1-R2)≦5

[0037] In addition, when the relationship between R1 and R2 satisfies the condition of the following formula, the decrease in the induced voltage is suppressed, and the distortion rate of the induced voltage is further reduced. (Formula) 2≦R2 / (R1-R2)≦3

[0038] 4 and 5, the structure of the inner end side of the teeth 112 in the stator core 110 will be described in detail. A wide portion 112b including a first extending end portion 112c and a second extending end portion 112d is provided at the inner end of the teeth 112. Also, a second notch portion 112c1 is formed at the inner end of the first extending end portion 112c extending in the positive rotation direction of the rotor 12, the second notch portion 112c1 being cut deeper toward the positive rotation direction.

[0039] The distortion rate of the induced voltage can be further reduced by arranging the first notch 121b and the second notch 112c1 approximately symmetrically across an air gap between the outer end 121a of the rotor 12 and the inner end (wide portion 112b) of the tooth 112. The edge 112e of the second notch 112c1 is preferably, but not limited to, linear or curved in plan view.

[0040] 5, if the dimension in the depth direction of the second cutout 112c1 is A, the dimension in the depth direction of the first extending end 112c when the second cutout 112c1 is not provided is A', the dimension in the width direction (rotation direction) of the second cutout 112c1 is B, and the dimension from the inner end of the first extending end 112c (reference number 112c2 in FIG. 5) to the center of the inner end of the wide portion (reference number 112c3 in FIG. 5) when the second cutout 112c1 is not provided is B', the relationship between A, A', B, and B' is adjusted to satisfy the following formula. This makes it possible to further reduce the distortion rate of the induced voltage while suppressing the decrease in the induced voltage. (Formula) 0.1≦A / A'≦0.9 and 0.1≦B / B'≦0.7

[0041] In addition, the relationship between A, A', B, and B' is adjusted so as to satisfy the following condition. This makes it possible to further reduce the distortion rate of the induced voltage while suppressing the decrease in the induced voltage. (Formula) 0.4≦A / A'≦0.6 and 0.3≦B / B'≦0.7 EXAMPLES

[0042] Specific examples of the above-described rotary compressor 1 and electric motor 10 will be described below. However, the present invention is not limited or restricted by the following examples.

[0043] [Relationship between the cut level of the first notch and the distortion rate of the induced voltage and the induced voltage] In this embodiment, an index of the cut amount of the first cutout portion 121b (cut amount of the outer end 121a of the magnetic pole 123) is expressed by [R2 / (R1-R2)], where R1 is the radius of the arc corresponding to the first outer end 121a1 of the rotor 12 and R2 is the radius of the arc corresponding to the second outer end 121a2 of the rotor 12. Hereinafter, this index is referred to as the "cut level." The smaller the value of [R2 / (R1-R2)], the larger the cut level is (the outer end 121a of the rotor 12 is cut deeply). On the other hand, the larger the value of [R2 / (R1-R2)], the smaller the cut level is (the outer end 121a of the rotor 12 is cut shallowly).

[0044] FIG. 6(a) shows the distortion rate of the induced voltage when the cut level [R2 / (R1-R2)] is changed. The horizontal axis of FIG. 6 shows the cut level [R2 / (R1-R2)]. The vertical axis of FIG. 6(a) shows the distortion rate of the induced voltage. Here, the distortion rate of the induced voltage shown on the vertical axis of FIG. 6 shows the ratio (%) to the distortion rate of the induced voltage in the motor 10 in which the notch (first notch 121b) on the rotor 12 side and the notch (second notch 112c1) on the stator 11 side 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) shows the cut level [R2 / (R1-R2)]. The vertical axis of FIG. 6(b) shows the induced voltage. Here, the induced voltage shown on the vertical axis of Figure 6 (b) indicates the ratio (%) to the induced voltage in an electric motor 10 in which the notch (first notch portion 121b) on the rotor 12 side and the notch (second notch portion 112c1) on the stator 11 side are not formed.

[0045] As shown in Figure 6(a), when the cut level is reduced from [R2 / (R1-R2)]=1 (the value of [R2 / (R1-R2)] is increased), the distortion rate of the induced voltage reaches its minimum value when [R2 / (R1-R2)]=2. When the cut level is reduced further, the distortion rate of the induced voltage increases as the cut level decreases (the value of [R2 / (R1-R2)] increases). In contrast, as shown in Figure 6(b), when the cut level is reduced from [R2 / (R1-R2)]=1 (the value of [R2 / (R1-R2)] is increased), the induced voltage increases.

[0046] From the results shown in FIG. 6(a) and FIG. 6(b), it was confirmed that the distortion rate of the induced voltage can be significantly reduced while suppressing the decrease in the induced voltage in the range of 2≦R2 / (R1-R2)≦5, especially in the range of 2≦R2 / (R1-R2)≦3. More specifically, when [R2 / (R1-R2)] is less than 2 (for example, when it is 1.5), the distortion rate of the induced voltage is reduced to some extent, but the induced voltage is significantly reduced (for example, compared to when [R2 / (R1-R2)]=2.5). On the other hand, when [R2 / (R1-R2)]=5, the induced voltage is high, and the distortion rate of the induced voltage remains at a value about 10% higher than when [R2 / (R1-R2)]=2, which is the minimum distortion rate of the induced voltage. On the other hand, when [R2 / (R1-R2)] is more than 5, the distortion rate of the induced voltage further increases. Therefore, the range in which the distortion rate of the induced voltage can be reduced while suppressing the decrease in the induced voltage is preferably 2≦R2 / (R1-R2)≦5. The distortion rate of the induced voltage at each cut level corresponds to the minimum value obtained by variously changing the cut rate [A / A'] (A and A' are as described above) on the depth direction side of the second cutout portion 112c1 of the tooth 112 of the stator 11 and the cut rate [B / B'] (B and B' are as described above) on the rotation direction side of the second cutout portion 112c1. The induced voltage at each cut level corresponds to the maximum value obtained by variously changing the cut rate [A / A'] and the cut rate [B / B'].

[0047] [Relationship between the cut rate of the second notch and the distortion rate of the induced voltage] Next, the distortion rate of the induced voltage when the cut rate [A / A'] on the depth direction side and the cut rate [B / B'] on the rotation direction side are changed in the second cut portion 112c1 formed at the inner end of the tooth 112 are shown in Tables 1 to 3 below. The induced voltage when the cut rates [A / A'] and [B / B'] are changed is also shown in Tables 4 to 6 below. The distortion rate of the induced voltage and the value of the induced voltage shown in Tables 1 to 6 correspond to the ratio (%) of the distortion rate of the induced voltage and the induced voltage measured in the electric motor 10 in which the first cut portion 121b and the second cut portion 112c1 are not formed, as in FIG. 6. The cut level [R2 / (R1-R2)] of the first cut portion 121b is as shown in each table.

[0048] [Table 1]

[0049] [Table 2]

[0050] [Table 3]

[0051] [Table 4]

[0052] [Table 5]

[0053] [Table 6]

[0054] As shown in Tables 1 to 6, in order to suppress the drop in induced voltage while achieving the effect of reducing the distortion rate of the induced voltage, it is desirable for the cut rate [A / A'] on the depth direction side and the cut rate [B / B'] on the rotation direction side to satisfy the conditions of [0.1≦A / A'≦0.9 and 0.1≦B / B'≦0.7]. In contrast, when [B / B'] exceeds 0.7, it is not desirable because the distortion rate of the induced voltage is high and the induced voltage is low. In addition, in order to suppress the drop in induced voltage while further achieving the effect of reducing the distortion rate of the induced voltage, it is desirable for the range to satisfy the condition of the following formula. (Formula) 0.4≦A / A'≦0.6 and 0.3≦B / B'≦0.7

[0055] [Relationship between the location 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 locations of the notches (first notch 121b, second notch 112c1) and the distortion rate of the induced voltage was confirmed. FIG. 8 shows the waveforms of the induced voltage in Example 1 and Comparative Examples 1 to 3 when the rotor 12 is rotated. The vertical axis in FIG. 8 corresponds to the ratio (%) of the amplitude of the fundamental wave of the induced voltage in Comparative Example 3 taken as 100%. In Example 1, [R2 / (R1-R2)]=2, [A / A']=0.5, and [B / B']=0.7.

[0056] Example 1 shown in FIG. 7(a) is an electric motor having a first notch 121a on the rotation direction positive side (second outer end 121a2) of the outer end of the magnetic pole 123 of the rotor 12, and a second notch 112c1 on the rotation direction positive side (first extended end 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 a notch is also provided on the rotation direction opposite side (second extended end 112d) of the inner end of the tooth 112. The rest is the same as Example 1. Comparative Example 2 shown in FIG. 7(c) is different from Example 1 in that no notch is formed on the inner end of the tooth 112. The rest is the same as Example 1. Comparative Example 3 shown in FIG. 7(d) is an electric motor having no notch formed on either the outer end of the magnetic pole 123 of the rotor 12 or the inner end of the tooth 112.

[0057] As shown in FIG. 8, in Example 1, an induced voltage close to a sine wave waveform was measured. That is, a waveform showing the induced voltage with few harmonic components other than the fundamental wave component was obtained. In contrast, in Comparative Examples 1 to 3, a waveform including many concaves and convexes was obtained compared to the sine wave waveform. This suggests that Comparative Examples 1 to 3 include many harmonic components other than the fundamental wave component compared to Example 1.

[0058] Table 7 below shows the distortion rate of the induced voltage (ratio (%) to Comparative Example 3) in Example 1 and Comparative Examples 1 to 3. As shown in Table 7, the distortion rate of the induced voltage in Example 1 was significantly reduced compared to Comparative Examples 1 to 3. That is, it was confirmed that the distortion rate of the induced voltage can be significantly reduced by arranging the first notch 121b on the rotor 12 side and the second notch 112c1 on the teeth 112 side approximately symmetrically with an air gap between them, as in Example 1.

[0059] [Table 7]

[0060] [Comparison of attractive forces acting on the inner ends of teeth] Fig. 9(a) is a graph showing the change in the attractive force acting on the inner ends of the teeth when the rotor 12 is rotated in Example 1 and Comparative Examples 1 to 3. Here, the vertical axis of Fig. 9(a) corresponds to the ratio (%) of the amplitude of the attractive force in Comparative Example 3, which is set to 100%. Also, the waveform in Comparative Example 3 is offset so that the center of its amplitude is 0. Furthermore, Fig. 9(b) is an enlarged view of the stator 11 (teeth 112) including arrows indicating the positive and negative attractive forces. Here, the tip side of the arrow shown in Fig. 9(b) corresponds to the positive side (plus side) of the attractive force, and the base end side of the arrow corresponds to the negative side (minus side) of the attractive force.

[0061] 9(a), the suction force acting on the teeth 112 in Example 1 was reduced compared to those in Comparative Example 1 and Comparative Example 3. That is, it was confirmed that by providing the first notch 121b on the rotor 12 side and the second notch 112c1 on the teeth 112 side substantially symmetrically with an air gap between them as in Example 1, the suction force acting on the inner end surface of the teeth 112 can be reduced, and vibration of the electric motor 10 and noise from the rotary compressor 1 can be suppressed.

[0062] The embodiments of the present invention have been described 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 includes modifications and improvements that can be made to the above-described embodiments without departing from the spirit of the present invention. The present invention also includes equivalents thereof. [Industrial Applicability]

[0063] The rotary compressor according to the present invention is used, for example, in home and commercial air conditioners, etc. However, its use is not limited thereto. [Explanation of symbols]

[0064] 1. Rotary compressor 10·······Electric motor 11. Stator 110 Stator core 111 York 112 Teeth 112a... Teeth body 112b Wide part of teeth 112c: An extension end provided on the positive side of the rotation direction 112c1 Second notch 112d: Extension end provided on the opposite side of the rotation direction 12 Rotor 121 Rotor core 121b First notch 122...Permanent magnet 123...Magnetic pole 13 Rotor shaft 20 Rotary compression mechanism 21...Cylinder 211...Compression chamber 22 Eccentric part 23. Laura 24... Vane 30... Container

Claims

1. A rotor; a stator including teeth provided on the outside of the rotor; Equipped with a first cutout portion that is cut deeper toward a positive side in a rotation direction of the rotor is formed on an outer peripheral surface of the rotor; a second cutout portion that is cut deeper toward the positive side in the rotation direction is formed at an inner end of the tooth on the positive side in the rotation direction, The tooth includes a main body portion and a wide portion provided on an inner end side of the main body portion, The wide portion includes a first extending end portion extending in the forward direction of the rotation and a second extending end portion extending in the reverse direction of the rotation, The inner end corresponds to the inner end of the first extending end portion, no notch is formed in the second extending end, a first outer end arranged on the opposite side of the first notch in the rotation direction of the rotor forms an arc centered on the rotation center of the rotor in a plan view, and an inner end surface of a portion of the tooth arranged on the opposite side of the second notch in the rotation direction forms a shape concentric with the arc in a plan view, Furthermore, the condition of the following formula 1 is satisfied: Electric motor. (Formula 1) 0.1≦A / A′≦0.9 and 0.1≦B / B′≦0.7 In formula 1, A is the dimension of the second cutout portion in the depth direction. In formula 1, A' is the dimension in the depth direction of the first extending end portion on the assumption that the second cutout portion is not provided. In formula 1, B is the dimension of the second cutout portion in the rotational direction. In formula 1, B' is the dimension from the inner end of the first extending end portion to the center of the inner end of the wide portion on the assumption that the second cutout portion is not provided.

2. Satisfy the condition of the following formula 2.

2. The electric motor according to claim 1. (Formula 2) 0.4≦A / A′≦0.6 and 0.3≦B / B′≦0.7

3. A rotor is provided with a plurality of magnetic poles, an outer end of each magnetic pole along the outer circumferential surface of the rotor includes, in a plan view, a first outer end portion that forms an arc centered on the rotation center of the rotor, and a second outer end portion that forms an arc centered on a position that is a predetermined distance away radially outward from the rotation center; The second outer end portion is disposed on the positive side in the rotation direction relative to the first outer end portion.

3. The electric motor according to claim 1 or 2.

4. The radius of the arc corresponding to the first outer end is R1, and the radius of the arc corresponding to the second outer end is R2. The relationship between R1 and R2 satisfies the condition of the following formula 3:

4. The electric motor according to claim 3. (Formula 3) 2≦R2 / (R1-R2)≦5

5. The electric motor according to any one of claims 1 to 4 is provided. Rotary compressor.

Images