JP7026811B2 - Stator, motor, compressor and air conditioner - Google Patents

Description

The present invention relates to a stator, a motor, a compressor and an air conditioner.

In the electric motor used for the compressor, the outer circumference of the stator core is fixed to the inside of the compressor housing. A recess serving as a refrigerant flow path is formed on the outer periphery of the stator core. Refrigerant, refrigerating machine oil or air flows through the recess to cool the motor (see, for example, Patent Documents 1 and 2).

Japanese Patent No. 4438895 (see FIG. 1) Japanese Patent No. 3586145 (see FIG. 2)

In order to improve the cooling efficiency of the motor, it is desirable that the cross-sectional area of the recess is large, but if the cross-sectional area of the recess is large, the contact area between the stator core and the housing decreases, and the bonding strength between the two decreases. , Vibration and noise are generated. Further, by increasing the cross-sectional area of the recess, the magnetic path in the stator core becomes narrow, magnetic flux is concentrated, iron loss increases, and motor efficiency decreases.

The present invention has been made to solve the above problems, and an object of the present invention is to improve the cooling efficiency of an electric motor while suppressing the generation of vibration and noise and suppressing the decrease in motor efficiency.

The stator of the present invention has a stator core in which a plurality of core portions are connected in the circumferential direction about the central axis. Each of the plurality of core portions has a yoke portion extending in the circumferential direction and a tooth extending inward in the radial direction from the yoke portion about the central axis. The yoke portion has an outer circumference and an inner circumference located at both ends in the radial direction, a connecting surface located at the end portion in the circumferential direction, and a recess having an opening on the outer circumference. The tooth has a side surface that forms a corner portion with the inner circumference of the yoke portion. The circumferential length W0 of the recess opening is shorter than the circumferential length W1 inside the recess opening in the radial direction. The shortest distance T1 from the corner portion to the recess and the length T0 of the connecting surface satisfy 0.65 ≦ T1 / T0 <1.

In the present invention, since the length W0 of the opening of the recess is shorter than the length W1 in the radial direction, the cross-sectional area of the recess can be increased while maintaining a large contact area between the stator core and the housing. Therefore, it is possible to suppress the generation of vibration and noise and improve the cooling efficiency of the motor. Further, since the shortest distance T1 from the corner to the recess and the length T0 of the connecting surface satisfy 0.65 ≦ T1 / T0 <1, the concentration of magnetic flux in the stator core is suppressed and the iron loss is reduced. The motor efficiency can be improved.

It is sectional drawing which shows the electric motor of Embodiment 1. FIG. It is sectional drawing which shows the core part of the stator core of Embodiment 1. FIG. It is a graph which shows the change of iron loss with respect to the ratio T1 / T0 of the distance T1 from the corner part of the core part to the concave part, and the length T0 of a connecting surface. It is a graph which shows the change of the motor efficiency with respect to the ratio T1 / T0 of the distance T1 from the corner part of the core part to the concave part, and the length T0 of a connecting surface. It is a graph which shows the change of the stator temperature with respect to the ratio T1 / T0 of the distance T1 from the corner part of the core part to the concave part, and the length T0 of a connecting surface. It is a figure which shows the distribution (A) of the iron loss density in the core part of Embodiment 1 in comparison with the 1st comparative example (B) and the 2nd comparative example (C). It is sectional drawing which shows the core part of the stator core of the 1st modification of Embodiment 1. FIG. It is sectional drawing which shows the core part of the stator core of the 2nd modification of Embodiment 1. FIG. It is sectional drawing which shows the electric motor of Embodiment 2. FIG. It is sectional drawing which shows the core part of the stator core of Embodiment 2. A perspective view (A) showing the core portion of the second embodiment, a perspective view (B) showing a state in which an insulator is attached to the core portion, and a perspective view (C) showing a state in which an insulator and an insulating film are attached to the core portion. Is. It is sectional drawing which shows the electric motor of Embodiment 3. FIG. It is sectional drawing which shows the core part of the stator core of Embodiment 3. FIG. It is sectional drawing which shows the rotary compressor to which the electric motor of each embodiment is applicable. It is a figure which shows the air conditioner provided with the rotary compressor of FIG.

Embodiment 1.
<Motor configuration>
The electric motor 100 of the first embodiment will be described. FIG. 1 is a cross-sectional view showing the electric motor 100 of the first embodiment. The electric motor 100 is a permanent magnet-embedded electric motor in which a permanent magnet 55 is embedded in a rotor 5, and is used, for example, in a rotary compressor 300 (FIG. 14).

The electric motor 100 is an electric motor called an inner rotor type, and has a stator 1 and a rotor 5 rotatably provided inside the stator 1. An air gap of, for example, 0.3 to 1.0 mm is formed between the stator 1 and the rotor 5.

Hereinafter, the direction of the central axis Ax, which is the rotation axis of the rotor 5, is referred to as "axial direction". Also. The circumferential direction around the central axis Ax (indicated by the arrow M in FIG. 1) is referred to as "circumferential direction". Further, the radial direction centered on the central axis Ax is referred to as "diameter direction". Note that FIG. 1 is a cross-sectional view of a plane orthogonal to the central axis Ax.

<Rotor configuration>
The rotor 5 has a cylindrical rotor core 50, a permanent magnet 55 attached to the rotor core 50, and a shaft 57 fixed to the center of the rotor core 50. The shaft 57 is, for example, the shaft of the compressor 300 (FIG. 14).

The rotor core 50 is formed by laminating laminated steel plates in the axial direction and integrating them at a caulking portion or the like. The laminated steel sheet is, for example, an electromagnetic steel sheet, and the plate thickness is, for example, 0.1 to 0.7 mm.

Along the outer circumference of the rotor core 50, a plurality of magnet insertion holes 51 into which the permanent magnets 55 are inserted are formed. The magnet insertion hole 51 is a through hole that penetrates the rotor core 50 in the axial direction. Each magnet insertion hole 51 corresponds to one magnetic pole, and the number of magnet insertion holes 51 corresponds to the number of poles. The number of magnet insertion holes 51 here is 6, so the number of magnetic poles is 6. However, the number of magnet insertion holes 51 is not limited to 6, and may be 2 or more.

The magnet insertion hole 51 is formed linearly along the outer circumference of the rotor core 50. One permanent magnet 55 is arranged in each magnet insertion hole 51. The magnet insertion hole 51 may be formed in a V shape protruding inward in the radial direction, for example, or two or more permanent magnets 55 may be arranged in one magnet insertion hole 51.

The permanent magnet 55 is a flat plate-shaped member, has a width in the circumferential direction of the rotor core 50, and has a thickness in the radial direction. The thickness of the permanent magnet 55 is, for example, 2 mm. The permanent magnet 55 is composed of, for example, a rare earth magnet containing neodymium (Nd), iron (Fe) and boron (B) as main components. The permanent magnet 55 is magnetized in the thickness direction.

Flux barriers (leakage flux suppression holes) 52 are formed at both ends of the magnet insertion hole 51 in the circumferential direction. The flux barrier 52 suppresses the leakage flux between adjacent magnetic poles. The core portion between the flux barrier 52 and the outer periphery of the rotor core 50 is a thin portion in order to suppress a short circuit of magnetic flux between adjacent magnetic poles. It is desirable that the thickness of the thin portion is the same as the thickness of the laminated steel plate of the rotor core 50.

A central hole 56 to which the shaft 57 described above is fixed is formed at the radial center of the rotor core 50. Further, through holes 53 and 54 through which the refrigerant of the compressor 300 passes are formed on the outer peripheral side of the central hole 56. Here, through holes 53 having a small inner diameter and through holes 54 having a large inner diameter are alternately arranged in the circumferential direction. The arrangement and shape of the through holes are arbitrary.

<Structure of stator>
The stator 1 has a stator core 2 and a coil 3 wound around the stator core 2. The stator core 2 is formed by laminating laminated steel plates in the axial direction and integrating them by a caulking portion 16. The laminated steel sheet is, for example, an electromagnetic steel sheet, and the plate thickness is, for example, 0.1 to 0.7 mm. The stator core 2 is fitted inside the housing 4 of the compressor 300 (FIG. 14).

The stator core 2 has an annular yoke 10 centered on the central axis Ax, and a plurality of teeth 12 extending radially inward from the yoke 10 (that is, in a direction toward the central axis Ax). Here, nine teeth 12 are arranged at regular intervals in the circumferential direction, but the number of teeth 12 may be 2 or more. A slot 13, which is a space for accommodating the coil 3, is formed between the teeth 12 adjacent to each other in the circumferential direction.

Further, the stator core 2 has a configuration in which a plurality of core portions 9 are connected in the circumferential direction for each tooth 12. Here, the same number of nine core portions 9 as the teeth 12 are connected in the circumferential direction. The core portion 9 is also referred to as a connected core or a split core. These core portions 9 are connected to each other by welding on the connecting surface 18.

The coil 3 is, for example, a magnet wire wound around a tooth 12 via an insulator 20 and an insulating film 25 (FIG. 11 (C)) described later. The wire diameter of the coil 3 is, for example, 1.0 mm. The coil 3 is wound around each tooth 12 by, for example, 80 turns by concentrated winding.

At the time of assembling the stator 1, the insulator 20 and the insulating film 25 (FIG. 11 (C)) are attached to the individual core portions 9, and the coil 3 is wound around the teeth 12 of the core portion 9 in that state. After that, a plurality of core portions 9 are combined in an annular shape, welded on the connecting surface 18 and integrated to obtain a stator core 2.

FIG. 2 is a cross-sectional view showing a core portion 9 of the stator core 2. FIG. 2 also shows a part of the housing 4. Of the annular yoke 10 shown in FIG. 1, the arcuate portion divided into each core portion 9 is referred to as a yoke portion 11.

The yoke portion 11 has an inner circumference 11a and an outer circumference 11b located at both ends in the radial direction, and a connecting surface 18 located at both ends in the circumferential direction. The inner circumference 11a is a plane orthogonal to a radial straight line L passing through the circumferential center of the teeth 12. The outer circumference 11b is a cylindrical surface centered on the central axis Ax (FIG. 1). The connecting surface 18 extends radially between the inner circumference 11a and the outer circumference 11b.

The teeth 12 extend radially inward from the central portion in the circumferential direction of the yoke portion 11. The tooth 12 has a tooth tip portion 12b facing the outer periphery of the rotor 5 (FIG. 1) at its radial inner end. The width Wt in the circumferential direction of the teeth 12 is constant over the radial direction except for the tooth tip portion 12b, and the width of the tooth tip portion 12b is wider than the width Wt. The teeth 12 has a side surface 12a which is a circumferential end. The side surface 12a faces the slot 13.

In the plane orthogonal to the central axis Ax, the inner circumference 11a of the yoke portion 11 and the side surface 12a of the teeth 12 are at right angles to each other. A corner portion C is formed between the inner circumference 11a of the yoke portion 11 and the side surface 12a of the teeth 12.

As described above, since the coil 3 is wound around the teeth 12 before the core portion 9 is assembled in an annular shape, the coil 3 can be wound at a high density even if the corner portion C is brought close to a right angle. The corner portion C does not necessarily have to be at a right angle, and a curved surface portion may be provided if necessary.

The yoke portion 11 has a recess 15 having an opening 15a on the outer peripheral portion 11b. The recess 15 has two edge edges 15b extending radially inward from both peripheral ends of the opening 15a and two edge edges 15c extending radially inward from the end P2 of each edge 15b.

The two edge edges 15b extend so as to widen the circumferential distance between them toward the inner side in the radial direction. Further, the two edge edges 15c extend in a V shape so that the circumferential distance between the two ends becomes narrower toward the inner side in the radial direction, and intersect at the point P1. Both the two edge 15b and the two edge 15c extend symmetrically with respect to the radial straight line L passing through the circumferential center of the teeth 12. Further, the point P1 is located on the straight line L.

The opening 15a of the recess 15 has a circumferential length W0. This length W0 is referred to as an opening length. Further, the recess 15 has a circumferential length W1 inside the opening 15a in the radial direction. This length W1 is the circumferential distance of the end P2 of the two edge 15b. Further, the length W1 is the maximum circumferential length of the recess 15.

The recess 15 has a shape in which the length W1 in the radial direction is longer than the opening length W0 (that is, the circumferential length in the outer peripheral portion 11b). This makes it possible to increase the cross-sectional area of the recess 15 while maintaining a large contact area between the outer peripheral portion 11b of the yoke portion 11 and the housing 4. That is, the bonding strength between the core portion 9 and the housing 4 can be increased, and the contact area between the refrigerant flowing in the recess 15 and the core portion 9 can be increased to improve the cooling efficiency.

The radial length D1 of the recess 15 is defined as the distance from the opening 15a of the recess 15 to the radially inner end of the recess 15 (ie, point P1). The radial length D1 of the recess 15 is longer than the opening length W0 of the recess 15. By lengthening the radial length D of the recess 15 in this way, the cross-sectional area of the recess 15 can be further increased, and the contact area between the refrigerant flowing in the recess 15 and the core portion 9 can be further increased.

Caulking portions 16 are formed on both sides of the recess 15 in the circumferential direction. The caulking portion 16 integrally fixes a laminated body of electrical steel sheets constituting the core portion 9. Here, the caulking portions 16 are formed on both sides of the concave portion 15 in the circumferential direction, but may be formed only on one side in the circumferential direction.

The shortest distance from the corner portion C to the recess 15 described above is represented by T1. Here, the shortest distance T1 is the distance from the corner portion C to one point on the edge 15c of the recess 15.

Next, the magnetic path in the core portion 9 will be described. The magnetic flux generated from the permanent magnet 55 (FIG. 1) of the rotor 5 flows into the teeth 12 from the tooth tip portion 12b and flows in the teeth 12 in the radial direction. Then, the magnetic flux flows from the teeth 12 into the yoke portion 11 and flows in the yoke portion 11 on both sides in the circumferential direction.

The magnetic path of the yoke portion 11 is the narrowest at the connecting surface 18 except for the periphery of the recess 15. Therefore, the length T0 of the connecting surface 18 can be considered as the minimum magnetic path width in the yoke portion 11.

Although the caulking portion 16 is formed in the yoke portion 11, the magnetic flux flows between the radial outer region and the radial inner region of the caulking portion 16, and the total widths B1 and B2 of these regions are The length of the connecting surface 18 is longer than T0. Therefore, as described above, the length T0 of the connecting surface 18 can be considered as the minimum magnetic path width in the yoke portion 11 (excluding the periphery of the recess 15).

Further, the region between the corner portion C and the recess 15 is the narrowest magnetic path in the core portion 9 (that is, the yoke portion 11 and the teeth 12). That is, the shortest distance T1 from the corner portion C to the recess 15 corresponds to the minimum magnetic path width in the core portion 9.

If the shortest distance T1 from the corner portion C to the recess 15 is too short with respect to the length T0 of the connecting surface 18 (that is, the minimum magnetic path width in the yoke portion 11), in the region between the corner portion C and the recess 15. The magnetic flux is concentrated, resulting in an increase in iron loss and a decrease in motor efficiency.

Therefore, in the first embodiment, the ratio of the shortest distance T1 from the corner portion C to the recess 15 (T1 /) with respect to the length T0 of the connecting surface 18 so that the concentration of the magnetic flux can be suppressed and the increase in iron loss can be suppressed. Set T0).

FIG. 3 is a graph showing the change in iron loss when T1 / T0 is changed. The horizontal axis shows T1 / T0, and the vertical axis shows iron loss. The iron loss is expressed by the rate of change (%) with respect to the reference value, using the iron loss when T1 / T0 is 1 as a reference value.

As shown in FIG. 3, as T1 / T0 increases, iron loss decreases. For example, the iron loss when T1 / T0 is 0.45 is + 200% of the reference value, but the iron loss when T1 / T0 is 0.65 is reduced to + 10% of the reference value. And T1 / T0 is 0. When it exceeds 65 , the change in iron loss becomes gradual, and when T1 / T0 becomes 1 or more, the iron loss becomes constant.

FIG. 4 is a graph showing changes in motor efficiency when T1 / T0 is changed. The horizontal axis represents T1 / T0, and the vertical axis represents motor efficiency. The motor efficiency is expressed by the rate of change (%) with respect to the reference value, with the motor efficiency when T1 / T0 is 1 as a reference value.

As shown in FIG. 4, the motor efficiency increases with the increase of T1 / T0. For example, the motor efficiency when T1 / T0 is 0.45 is -5.0% of the reference value, but the motor efficiency when T1 / T0 is 0.65 increases to -0.3% of the reference value. do. And T1 / T0 is 0. When it exceeds 65 , the change in motor efficiency becomes gradual, and when T1 / T0 becomes 1 or more, the motor efficiency becomes constant.

From the results shown in FIGS. 3 and 4, it can be seen that when T1 / T0 is 0.65 or more, the iron loss decreases and the motor efficiency increases. Further, it can be seen that when T1 / T0 becomes 1 or more, no further decrease in iron loss or increase in motor efficiency is observed.

FIG. 5 is a graph showing a change in the stator temperature when T1 / T0 is changed. The horizontal axis represents T1 / T0, and the vertical axis represents the stator temperature. The stator temperature is the temperature of the stator 1 when a specified current is passed through the coil 3, and the stator temperature when T1 / T0 is 1 is used as a reference value and is expressed as a rate of change (%) with respect to this reference value. There is.

As shown in FIG. 5, the stator temperature rises linearly with the increase of T1 / T0. For example, the motor efficiency when T1 / T0 is 0.65 is −5.5% of the reference value, and the motor efficiency when T1 / T0 is 1.0 is the reference value ± 0%, and T1 / T0. When is 1.2, the motor efficiency is + 3.0% of the reference value.

This is because as T1 / T0 becomes larger, the cross-sectional area of the recess 15 becomes smaller, the contact area between the refrigerant in the recess 15 and the core portion 9 decreases, and the cooling efficiency decreases. When the cooling efficiency decreases, the temperature of the electric motor 100 rises, and the permanent magnet 55 may be demagnetized.

Therefore, as shown by arrows E in FIGS. 3 to 5, the effect of reducing iron loss and the effect of improving motor efficiency are most prominent, and T1 / T0 can be made as small as possible, 0.65 ≦ T1 /. It can be seen that the range of T0 <1.0 is desirable.

In the case of the stator core 2 in which the plurality of core portions 9 are connected in an annular shape, the winding of the coil 3 is performed before assembling the plurality of core portions 9 to the stator core 2. In this case, since it is easier to wind the coil 3 as compared with the stator core having an integral structure, the corner portion C between the inner peripheral circumference 11a of the yoke portion 11 and the side surface 12a of the teeth 12 is often brought closer to a right angle, and the corner is formed. The distance between the portion C and the recess 15 tends to be short. Therefore, if the cross-sectional area of the recess 15 is increased, the magnetic flux tends to concentrate between the corner portion C and the recess 15.

In the first embodiment, the opening length W0 of the recess 15 is made shorter than the length W1 in the radial direction, and the shortest distance T1 from the corner portion C to the recess 15 and the length T0 of the connecting surface 18 are 0. It is configured to satisfy .65 ≦ T1 / T0 <1. This configuration is particularly effective in the stator core 2 in which a plurality of core portions 9 are connected.

Returning to FIG. 2, the magnetic flux flowing from the teeth 12 into the yoke portion 11 flows separately on both sides in the circumferential direction at the yoke portion 11. In order not to block the magnetic flux flowing from the teeth 12 into the yoke portion 11 as much as possible, it is desirable that the width W1 which is the maximum width of the recess 15 is shorter than the width Wt of the teeth 12. That is, it is desirable to satisfy W1 <Wt.

Further, in order to increase the cross-sectional area of the recess 15, it is desirable that the shortest distance T1 from the corner portion C to the recess 15 is shorter than 1/2 of the width Wt of the teeth 12. That is, it is desirable to satisfy T1 <Wt × 1/2.

Further, the portion of the recess 15 including the two end edges 15c projects radially inward from the position where the distance from the corner portion C is the shortest distance T1 in a V shape. Therefore, the cross-sectional area of the recess 15 can be increased without shortening the shortest distance T1 from the corner portion C to the recess 15 as much as possible.

6 (A) to 6 (C) are diagrams showing the analysis results of the iron loss density in the core portion 9. FIG. 6A is a diagram showing the iron loss density distribution in the core portion 9 of the first embodiment satisfying 0.65 ≦ T1 / T0 <1. FIG. 6B is a diagram showing the iron loss density distribution in the core portion of the first comparative example satisfying T1 / T0> 1. FIG. 6C is a diagram showing the iron loss density distribution in the core portion of the second comparative example satisfying T1 / T0 <0.65. In FIGS. 6A to 6C, the high and low iron loss densities are shown by the density of dots.

As shown in FIG. 6B, in the first comparative example in which T1 / T0 is larger than 1, no increase in iron loss density is observed except for the tooth tip portion 12b of the teeth 12. This is because the concave portion 15 is small, so that there is no narrow portion of the magnetic path other than the tooth tip portion 12b of the tooth 12. However, in this first comparative example, since the cross-sectional area of the recess 15 is small, sufficient cooling efficiency cannot be obtained.

On the other hand, as shown in FIG. 6C, in the second comparative example in which T1 / T0 is smaller than 0.65, a portion having a high iron loss density is centered on the region between the corner portion C and the recess 15. Can be seen. This is because the magnetic path between the corner portion C and the recess 15 is narrowed and the magnetic flux is concentrated. In this second comparative example, a sufficient cooling efficiency can be obtained because the cross-sectional area of the recess 15 is large, but the motor efficiency is lowered due to the increase in iron loss.

On the other hand, as shown in FIG. 6A, in the core portion 9 of the first embodiment satisfying 0.65 ≦ T1 / T0 <1.0, the iron loss density is slightly around the corner portion C. Although high parts can be seen, it can be seen that there are few parts with high iron loss density as compared with FIG. 6 (C). This is because the concentration of the magnetic flux is suppressed by not making the magnetic path between the corner portion C and the recess 15 too narrow. That is, in the first embodiment, the cross-sectional area of the recess 15 can be increased to improve the cooling efficiency, and the increase in iron loss can be suppressed to improve the motor efficiency.

<Effect of embodiment>
As described above, in the first embodiment, the yoke portion 11 of the core portion 9 constituting the stator core 2 has a recess 15 that opens to the outer peripheral portion 11b thereof. The opening length W0 of the recess 15 is shorter than the length W1 on the inner side in the radial direction, and the shortest distance T1 from the corner portion C to the recess 15 and the length T0 of the connecting surface 18 are 0.65 ≦ T1. / T0 <1 is satisfied. Therefore, the cross-sectional area of the recess 15 can be increased to improve the cooling efficiency, and the contact area between the stator core 2 and the housing 4 can be increased to increase the coupling strength between the two and reduce vibration and noise. In addition, the concentration of magnetic flux can be suppressed, iron loss can be reduced, and motor efficiency can be improved.

Further, since the radial length D1 of the recess 15 is longer than the opening length W0, the contact area between the stator core 2 and the housing 4 is made larger, and the cross-sectional area of the recess 15 is made larger to improve the cooling efficiency. Can be improved.

Further, since the length W1 inside the opening 15a of the recess 15 in the radial direction is shorter than the width Wt in the circumferential direction of the teeth 12, the magnetic flux flowing from the teeth 12 to the yoke portion 11 should not be blocked as much as possible. Can be done. As a result, the concentration of magnetic flux can be suppressed, iron loss can be reduced, and motor efficiency can be improved.

Further, since the recess 15 has a protruding shape portion (that is, a V-shaped portion having two edge 15c) protruding inward in the radial direction from a position where the distance from the corner portion C is the shortest distance T1, the corner portion is formed. The cross-sectional area of the recess 15 can be increased without shortening the shortest distance T1 from C to the recess 15 as much as possible.

Further, since the permanent magnet 55 is composed of a rare earth magnet, the amount of magnetic flux flowing into the teeth 12 increases, and the effect of suppressing the decrease in the magnetic path width of the teeth 12 and the yoke portion 11 is remarkable. Further, since rare earth magnets are easily demagnetized at high temperatures, the effect of suppressing demagnetization is remarkably exhibited by improving the cooling efficiency by increasing the cross-sectional area of the recess 15.

First modification example.
FIG. 7 is a cross-sectional view showing a core portion 9 of the first modification of the first embodiment. The core portion 9 of the first modification is different from the core portion 9 of the first embodiment in the shape of the recess 15. That is, the recess 15 of the first embodiment has a protruding shape portion (that is, a portion including two edge edges 15c) protruding inward in the radial direction from a position where the distance from the corner portion C is the shortest distance T1. However, in the recess 15 of the first modification, the radial inner edge 15c extends linearly.

Specifically, the recess 15 of the first modification is a straight line of the opening 15a, the two end edges 15b extending radially inward from both ends in the circumferential direction of the opening 15a, and the end P2 of the two end edges 15b. It has an edge 15c tied in a shape.

In this first modification, the distance from the corner portion C to the linear edge 15c of the recess 15 is the shortest distance T1 from the corner portion C to the recess 15, and 0.65 ≦ T1 / T0 <1 is satisfied. do. Other configurations are the same as those in the first embodiment.

Second modification example.
FIG. 8 is a cross-sectional view showing the core portion 9 of the second modification of the first embodiment. The core portion 9 of the second modification is different from the core portion 9 of the first embodiment in the shape of the recess 15. That is, the recess 15 of the first embodiment has a protruding shape portion (that is, a portion including two edge edges 15c) protruding inward in the radial direction from a position where the distance from the corner portion C is the shortest distance T1. However, in the recess 15 of the second modification, the protruding shape portion has a further curved shape.

Specifically, the recess 15 of the first modification is a straight line of the opening 15a, the two end edges 15b extending radially inward from both ends in the circumferential direction of the opening 15a, and the end P2 of the two end edges 15b. It has an edge 15c connected in a shape and an edge 15d extending radially inward from the edge 15c in an arc shape.

In this second modification, the distance from the corner portion C to the curved end edge 15d of the recess 15 is the shortest distance T1 from the corner portion C to the recess 15, and 0.65 ≦ T1 / T0 <1 is satisfied. .. Other configurations are the same as those in the first embodiment.

Embodiment 2.
Next, the second embodiment will be described. FIG. 9 is a cross-sectional view showing the electric motor 100A of the second embodiment. The motor 100A of the second embodiment is different from the motor 100 of the first embodiment in that a hole 17 is formed adjacent to the recess 15 of the stator core 2.

FIG. 10 is a cross-sectional view showing a core portion 9A constituting the stator core 2. The yoke portion 11 of the core portion 9A has a recess 15 that opens to the outer circumference 11b, and a hole portion 17 that is formed adjacent to the inside of the recess 15 in the radial direction.

As described in the first modification (FIG. 7) of the first embodiment, the recess 15 has an opening 15a, two edge edges 15b extending radially inward from both ends in the circumferential direction of the opening 15a, and two. It has a linear edge 15c connecting the ends of the edges 15b. The opening length W0 of the recess 15 is shorter than the length W1 on the inner side in the radial direction.

The hole portion 17 has an outer edge 17a located on the outer side in the radial direction, an inner edge 17b located on the inner side in the radial direction, and side edge 17c located on both sides in the circumferential direction. The outer edge 17a faces the edge 15c of the recess 15. Both the outer edge 17a and the inner edge 17b have a curved shape, but are not limited thereto.

The circumferential width Ws of the hole 17 is shorter than the opening length W0 of the recess 15. The width Ws is the distance in the circumferential direction of the two edge edges 17c of the hole portion 17 . Further, the distance D2 from the outer peripheral portion 11b of the yoke portion 11 to the radial inner end portion of the hole portion 17 is longer than the opening length W0.

The hole portion 17 is used to fix the insulator 20 attached to the core portion 9A. Here, the insulator 20 will be described.

11 (A) to 11 (C) are perspective views showing the attachment of the insulator 20 to the core portion 9A. 11 (A) is a perspective view showing the core portion 9A, and FIG. 11 (B) is a perspective view showing a state in which the insulator 20 is attached to the core portion 9A. FIG. 11C is a perspective view showing a state in which the insulator 20 and the insulating film 25 are attached to the core portion 9A.

As shown in FIG. 11A, stepped portions 101 are formed at both ends of the core portion 9A in the axial direction. The step portion 101 is formed, for example, along the side surface 12a of the teeth 12 and the inner circumference 11a of the yoke portion 11.

As shown in FIG. 11B, insulators 20 are attached to both ends of the core portion 9A in the axial direction. The insulator 20 has a wall portion 21 attached to the yoke portion 11, a body portion 22 attached to the main portion of the teeth 12, and a flange portion 23 attached to the tooth tip portion 12b of the teeth 12. The wall portion 21 and the flange portion 23 face each other in the radial direction with the body portion 22 interposed therebetween.

The wall portion 21 is formed with a protrusion 24 that fits into the hole portion 17 of the core portion 9A. The insulator 20 is positioned with respect to the core portion 9A by fitting the protrusion 24 into the hole portion 17. The body portion 22 is a portion around which the coil 3 is wound.

As shown in FIG. 11C, the insulating film 25 is attached so as to cover the side surface 12a of the teeth 12 and the inner circumference 11a of the yoke portion 11. In this state, the coil 3 is wound around the body portion 22 of the insulator 20. The insulator 20 and the insulating film 25 insulate the core portion 9A from the coil 3. The wall portion 21 and the flange portion 23 guide the coil 3 from both sides in the radial direction.

By combining the plurality of core portions 9A around which the coil 3 is wound in an annular shape and welding them on the connecting surface 18, the stator 1A shown in FIG. 9 can be obtained.

Returning to FIG. 10, in the second embodiment, the shortest distance T2 from the corner portion C to the hole portion 17 is shorter than the shortest distance T1 from the corner portion C to the recess 15. That is, T1> T2 is established. Therefore, the region between the corner portion C and the hole portion 17 is the narrowest magnetic path in the core portion 9A.

Therefore, in the second embodiment, the shortest distance T2 from the corner portion C to the hole portion 17 and the length T0 of the connecting surface 18 of the yoke portion 11 satisfy 0.65 ≦ T2 / T0 <1. By satisfying 0.65 ≦ T2 / T0, as described in the first embodiment, the concentration of the magnetic flux can be suppressed and the iron loss can be reduced. Further, by satisfying T2 / T0 <1, the cross-sectional area of the hole portion 17 can be increased, and the insulator 20 can be reliably positioned on the core portion 9A.

Further, since the region between the corner portion C and the recess 15 is the second narrowest magnetic path in the core portion 9A, the shortest distance T1 from the corner portion C to the recess 15 and the connecting surface 18 of the yoke portion 11 It is desirable that the length T0 satisfies 0.65 ≦ T1 / T0 <1.

Further, it is desirable that the distance D2 from the outer peripheral portion 11b of the yoke portion 11 to the radially inner end portion of the hole portion 17 is longer than the opening length W0 of the concave portion 15. As a result, the contact area between the core portion 9A and the housing 4 can be increased to increase the bonding strength between the two, and the cross-sectional area of the recess 15 and the hole portion 17 can be increased.

Further, it is desirable that the length W1 inside the opening 15a of the recess 15 in the radial direction is shorter than the width Wt in the circumferential direction of the teeth 12. Thereby, as described in the first embodiment, it is possible to prevent the magnetic flux flowing from the teeth 12 into the yoke portion 11 as much as possible, and it is possible to suppress the concentration of the magnetic flux and reduce the iron loss.

Further, in order to increase the cross-sectional area of the recess 15 and the hole 17, it is desirable that the shortest distance T2 from the corner C to the hole 17 is shorter than 1/2 of the width Wt of the teeth 12. That is, it is desirable to satisfy T2 <Wt × 1/2.

Other configurations of the electric motor 100A of the second embodiment are the same as those of the electric motor 100 of the first embodiment. Further, the electric motor 100A of the second embodiment is used for, for example, the compressor 300 (FIG. 14).

In the examples shown in FIGS. 9 to 11, the recess 15 has the shape described in the first modification (FIG. 7) of the first embodiment, but in the first embodiment (FIG. 2). It may have the shape described above, or may have the shape described in the second modification (FIG. 8).

As described above, in the second embodiment, the yoke portion 11 of the core portion 9A constituting the stator core 2 has a recess 15 that opens to the outer peripheral portion 11b thereof, and has a hole portion 17 inside the concave portion 15 in the radial direction. .. The opening length W0 of the recess 15 is shorter than the radial inner length W1 of the opening 15a of the recess 15. Further, the shortest distance T2 from the corner portion C to the hole portion 17 and the length T0 of the connecting surface 18 satisfy 0.65 ≦ T2 / T0 <1. Therefore, the cross-sectional area of the recess 15 is increased to improve the cooling efficiency, the cross-sectional area of the hole 17 is increased to prevent the insulator 20 from being displaced, and the contact area between the core portion 9A and the housing 4 is secured. And vibration and noise can be reduced. In addition, the concentration of magnetic flux can be suppressed, iron loss can be reduced, and motor efficiency can be improved.

Embodiment 3.
Next, the third embodiment will be described. FIG. 12 is a cross-sectional view showing the electric motor 100B of the third embodiment. The electric motor 100B of the third embodiment is different from the electric motor 100 of the first embodiment in that a recess 19 is formed on the outer periphery of the stator core 2.

FIG. 13 is a cross-sectional view showing a core portion 9B constituting the stator core 2. The yoke portion 11 of the core portion 9B has a recessed portion 19 at a corner portion between the outer peripheral portion 11b and the connecting surface 18. Therefore, the length T0 of the connecting surface 18 that defines the width of the magnetic path of the yoke portion 11 is shorter than that of the first embodiment.

The recessed portion 19 is provided to accommodate the molten metal when the connecting surfaces 18 of the plurality of core portions 9B are joined by welding. By accommodating the molten metal in the recessed portion 19, it is possible to prevent the metal from protruding outside the outer peripheral portion 11b of the yoke portion 11, and it is possible to suppress a decrease in the roundness of the outer peripheral portion 11b. As a result, the coupling strength between the stator core 2 and the housing 4 can be increased.

Other configurations of the electric motor 100B of the third embodiment are the same as those of the electric motor 100 of the first embodiment. Further, the electric motor 100B of the third embodiment is used, for example, in the compressor 300 (FIG. 14).

In the examples shown in FIGS. 12 to 13, the recess 15 had the shape described in the first embodiment (FIG. 2), but the first modified example (FIG. 7) or the second modified example. It may have the shape described in FIG. 8 (FIG. 8). Further, as described in the second embodiment, the hole portion 17 (FIG. 10) may be formed inside the concave portion 15 in the radial direction.

As described above, in the third embodiment, the recessed portion 19 is provided at the intersection of the outer peripheral portion 11b of the core portion 9B constituting the stator core 2 and the connecting surface 18. Therefore, in addition to the effect described in the first embodiment, it is possible to prevent the metal from protruding to the outside of the outer peripheral portion 11b of the yoke portion 11 at the time of melting, and it is possible to suppress a decrease in the roundness of the outer peripheral portion 11b. .. As a result, the coupling strength between the stator core 2 and the housing 4 can be increased.

<Rotary compressor>
Next, the rotary compressor 300 to which the motors 100 (100A, 100B) of the first to third embodiments described above can be applied will be described. FIG. 14 is a vertical sectional view showing the configuration of the rotary compressor 300. The rotary compressor 300 is used for, for example, an air conditioner, and includes a closed container 307, a compression mechanism 301 arranged in the closed container 307, and an electric motor 100 for driving the compression mechanism 301. The housing 4 shown in FIG. 1 is a part of the closed container 307.

The compression mechanism 301 includes a cylinder 302 having a cylinder chamber 303, a shaft 57 of the motor 100, a rolling piston 304 fixed to the shaft 57, and a vane that divides the inside of the cylinder chamber 303 into a suction side and a compression side (not shown). And an upper frame 305 and a lower frame 306 into which the shaft 57 is inserted to close the axial end face of the cylinder chamber 303. An upper discharge muffler 308 and a lower discharge muffler 309 are mounted on the upper frame 305 and the lower frame 306, respectively.

The closed container 307 is a cylindrical container. Refrigerating machine oil (not shown) that lubricates each sliding portion of the compression mechanism 301 is stored in the bottom of the closed container 307. The shaft 57 is rotatably held by an upper frame 305 and a lower frame 306 as bearing portions.

The cylinder 302 includes a cylinder chamber 303 inside, and the rolling piston 304 rotates eccentrically in the cylinder chamber 303. The shaft 57 has an eccentric shaft portion, and a rolling piston 304 is fitted to the eccentric shaft portion.

The stator 1 of the electric motor 100 is incorporated inside the housing 4 of the closed container 307 by a method such as shrink fitting, press fitting, or welding. Power is supplied to the coil 3 of the stator 1 from the glass terminal 311 fixed to the closed container 307. The shaft 57 is fixed to a central hole formed in the center of the rotor core 50 (FIG. 2) of the rotor 5.

An accumulator 310 for storing the refrigerant gas is attached to the outside of the closed container 307. A suction pipe 313 is fixed to the closed container 307, and refrigerant gas is supplied from the accumulator 310 to the cylinder 302 via the suction pipe 313. Further, a discharge pipe 312 for discharging the refrigerant to the outside is provided in the upper part of the closed container 307.

The refrigerant gas supplied from the accumulator 310 is supplied into the cylinder chamber 303 of the cylinder 302 through the suction pipe 313. When the motor 100 is driven by the energization of the inverter and the rotor 5 rotates, the shaft 57 rotates together with the rotor 5. Then, the rolling piston 304 fitted to the shaft 57 rotates eccentrically in the cylinder chamber 303, and the refrigerant is compressed in the cylinder chamber 303. The refrigerant compressed in the cylinder chamber 303 passes through the discharge mufflers 308 and 309, and further rises in the closed container 307 through the through holes 53 and 54 of the rotor 5 and the recess 15 (FIG. 2) of the stator 1. The refrigerant rising in the closed container 307 is discharged from the discharge pipe 312 and supplied to the high pressure side of the refrigeration cycle.

The electric motors 100 (100A, 100B) of the above-described first to third embodiments have high motor efficiency due to the suppression of demagnetization of the permanent magnet 55, and the coupling strength between the stator core 2 and the housing 4 is high. Vibration and noise are suppressed by the improvement. Therefore, by applying the electric motor 100 to the rotary compressor 300, the operating efficiency of the rotary compressor 300 can be improved and the quietness can be improved.

The electric motors 100 (100A, 100B) of the first to third embodiments can be used not only for the rotary compressor 300 but also for other types of compressors.

<Air conditioner>
Next, the air conditioner 400 (refrigeration cycle device) provided with the rotary compressor 300 described above will be described. FIG. 15 is a diagram showing the configuration of the air conditioner 400. The air conditioner 400 includes a compressor 401, a condenser 402, a throttle device (decompression device) 403, and an evaporator 404. The compressor 401, the condenser 402, the throttle device 403 and the evaporator 404 are connected by a refrigerant pipe 407 to form a refrigeration cycle. That is, the refrigerant circulates in the order of the compressor 401, the condenser 402, the throttle device 403, and the evaporator 404.

The compressor 401, the condenser 402, and the throttle device 403 are provided in the outdoor unit 410. The compressor 401 is composed of the rotary compressor 300 shown in FIG. The outdoor unit 410 is provided with a blower 405 that supplies outdoor air to the condenser 402. The evaporator 404 is provided in the indoor unit 420. The indoor unit 420 is provided with a blower 406 that supplies indoor air to the evaporator 404.

The operation of the air conditioner 400 is as follows. The compressor 401 compresses and sends out the sucked refrigerant. The condenser 402 exchanges heat between the refrigerant flowing in from the compressor 401 and the outdoor air, condenses the refrigerant, liquefies it, and sends it to the refrigerant pipe 407. The blower 405 supplies outdoor air to the condenser 402. The throttle device 403 adjusts the pressure of the refrigerant flowing through the refrigerant pipe 407 by changing the opening degree.

The evaporator 404 exchanges heat between the refrigerant reduced to a low pressure by the throttle device 403 and the air in the room, causes the refrigerant to take heat of the air, evaporate (vaporize) it, and send it to the refrigerant pipe 407. The blower 406 supplies the room air to the evaporator 404. As a result, the cold air whose heat has been taken away by the evaporator 404 is supplied to the room.

As the compressor 300 of the air conditioner 400, the motors 100 (100A, 100B) of the above-described first to third embodiments can be applied, thereby having high operating efficiency and quietness. Therefore, the energy efficiency of the air conditioner 400 can be improved and the quietness can be improved.

Although the preferred embodiment of the present invention has been specifically described above, the present invention is not limited to the above-described embodiment, and various improvements or modifications are made without departing from the gist of the present invention. be able to.

1 stator, 2 insulator, 3 coil, 4 housing, 5 rotor, 9,9A, 9B core part, 10 stator core, 11 yoke, 11a inner circumference, 11b outer circumference, 12 teeth, 12a side surface, 12b tooth tip part, 13 slot , 15 recesses, 15a openings, 15b, 15c, 15d edges, 16 caulking, 17 holes, 17a outer edges, 17b inner edges, 17c side edges, 18 connecting surfaces, 19 recesses, 24 protrusions, 50. Rotor core, 51 magnet insertion hole, 55 permanent magnet, 57 shaft, 100, 100A, 100B motor, 110 yoke part, 300 rotary compressor (compressor), 301 frame, 310 compression mechanism, 400 air conditioner, 401 compressor, 402 Condenser, 403 Squeezer, 404 Evaporator, 410 Outdoor unit, 420 Indoor unit.

Claims (18)

It has a stator core in which a plurality of core parts are connected in the circumferential direction centered on the central axis.
Each of the plurality of core portions has a yoke portion extending in the circumferential direction and a tooth extending inward in the radial direction from the yoke portion about the central axis.
The yoke portion has an outer circumference and an inner circumference located at both ends in the radial direction, a connecting surface located at the end portion in the circumferential direction, and a recess having an opening in the outer circumference.
The tooth has a side surface that forms a corner portion between the yoke portion and the inner circumference thereof.
The circumferential length W0 of the opening of the recess is shorter than the circumferential length W1 inside the radial inside of the opening of the recess.
The shortest distance T1 from the corner portion to the recess and the length T0 of the connecting surface are
0.65 ≤ T1 / T0 <1
The stator that satisfies. The recess has the radial length D1.
The stator according to claim 1, wherein the length D1 is longer than the length W0. The stator according to claim 1 or 2, wherein the length W1 is shorter than the width Wt in the circumferential direction of the teeth. The stator according to any one of claims 1 to 3, wherein the shortest distance T1 is shorter than 1/2 of the width Wt in the circumferential direction of the teeth. The stator according to any one of claims 1 to 4, wherein the recess has a protruding shape portion that protrudes inward in the radial direction from a position where the distance from the corner portion is the shortest distance T1. The stator according to claim 5, wherein the protruding shape portion has a curved shape. The stator according to any one of claims 1 to 4, wherein the recess has a shape in which the length in the circumferential direction becomes longer toward the inner side in the radial direction. The stator according to any one of claims 1 to 7, wherein the yoke portion has a recessed portion at a portion where the outer periphery and the connecting surface intersect. The yoke portion has a hole portion inside the concave portion in the radial direction.
The shortest distance T2 from the corner portion to the hole portion and the length T0 of the connecting surface are
0.65 ≤ T2 / T0 <1
The stator according to any one of claims 1 to 8. The recess has two edge extending from both ends of the opening toward the inside in the radial direction so as to widen the gap, and a V-shape inward in the radial direction from the end of each of the two end edges. Has two edges extending in a shape
The stator according to any one of claims 1 to 5. It has a stator core in which a plurality of core parts are connected in the circumferential direction centered on the central axis.
Each of the plurality of core portions has a yoke portion extending in the circumferential direction and a tooth extending inward in the radial direction from the yoke portion about the central axis.
The yoke portion has an outer circumference and an inner circumference located at both ends in the radial direction, a connecting surface located at the end portion in the circumferential direction, a recess having an opening in the outer circumference, and a concave portion in the radial direction with respect to the concave portion. It has a hole located inside and has
The tooth has a side surface that forms a corner portion between the yoke portion and the inner circumference thereof.
The circumferential length W0 of the opening of the recess is shorter than the circumferential length W1 inside the radial inside of the opening of the recess.
The shortest distance T2 from the corner portion to the hole portion and the length T0 of the connecting surface are
0.65 ≤ T2 / T0 <1
Satisfy the stator. The stator according to claim 11 , wherein the distance D2 from the opening of the recess to the radial inner end of the hole is longer than the length W0. The stator according to claim 11 or 12 , wherein the length W1 is shorter than the width Wt in the circumferential direction of the teeth. The stator according to any one of claims 11 to 13 , wherein the shortest distance T2 is shorter than 1/2 of the width Wt in the circumferential direction of the teeth. The stator according to any one of claims 1 to 14 ,
An electric motor surrounded by the stator and equipped with a rotor that can rotate around the central axis. The rotor has a rotor core and a permanent magnet attached to the rotor core.
The electric motor according to claim 15 , wherein the permanent magnet is a rare earth magnet containing neodymium, iron and boron. A motor according to claim 15 or 16 , and a compression mechanism driven by the motor.
The recess of the stator is a compressor that is a flow path for the refrigerant. Equipped with compressor, condenser, decompressor and evaporator,
The compressor is an air conditioner including the electric motor according to claim 15 or 16 and a compression mechanism driven by the electric motor.

Images