WO2023233629A1

WO2023233629A1 - Stator, electric motor, compressor, and refrigeration cycle device

Info

Publication number: WO2023233629A1
Application number: PCT/JP2022/022508
Authority: WO
Inventors: 優樹東
Original assignee: 三菱電機株式会社
Priority date: 2022-06-02
Filing date: 2022-06-02
Publication date: 2023-12-07

Abstract

This stator core has an annular core back, a tooth extending from the core back to the inside in the radial direction, and a slot adjacent to the tooth in the circumferential direction. A winding is wound around the tooth with an insulating portion interposed therebetween. The tooth has an end surface facing in the axial direction of the stator core, a side surface facing a slot, and a step portion formed between the end surface and the side surface. The insulating portion has a first surface covering the end surface of the tooth, a second surface facing the slot, and a third surface that is a curved surface or a sloped surface extending from the first surface to the second surface. In a cross-section orthogonal to the extending direction of the tooth, the boundary between the first surface and the third surface is denoted by point P, the boundary between the second surface and the third surface is denoted by point Q, and the intersection of a first line that passes through the point P and is parallel with the axial direction and a second line that passes through the point Q and is orthogonal to the axial direction is denoted by U. The height A of the step portion in the axial direction, the width B of the step portion in a direction orthogonal to the axial direction, the distance D1 from the point P to the intersection U, and the distance D2 from the point Q to the intersection U satisfy the relationships of D1 ≤ A and D2 ≤ B.

Description

Stators, electric motors, compressors and refrigeration cycle equipment

The present disclosure relates to a stator, an electric motor, a compressor, and a refrigeration cycle device.

The stator of the electric motor includes a stator core having teeth, a winding wound around the teeth, and an insulating part interposed between the teeth and the winding. It is also known to provide a stepped portion at the axial end of the teeth in order to shorten the circumferential length of the winding (for example, Patent Document 1).

JP 2016-82683 (see abstract)

However, when the teeth are provided with stepped portions, the insulating portions covering the teeth are locally thinned, making the insulating portions more likely to be damaged. If the thickness of the insulation part is increased to prevent damage, the circumference of the winding becomes longer.

The present disclosure has been made to solve the above problems, and aims to shorten the circumferential length of the winding.

A stator according to the present disclosure includes a stator core having an annular core back, teeth extending radially inward from the core back, slots adjacent to the teeth in the circumferential direction of the core back, and an insulating core provided in the teeth. and a winding wound around the teeth via an insulating part. The teeth have an end face facing in the axial direction of the stator core, a side face facing the slot, and a step portion formed between the end face and the side face. The insulating part has a first surface that covers the end surface of the teeth, a second surface facing the slot, and a third surface that is a curved surface or an inclined surface extending from the first surface to the second surface. has. In the cross section perpendicular to the extending direction of the teeth, the boundary between the first surface and the third surface is a point P, the boundary between the second surface and the third surface is a point Q, and passing through point P Let U be the intersection of a first straight line parallel to the axial direction and a second straight line passing through point Q and perpendicular to the axial direction. The height A of the stepped portion in the axial direction, the width B of the stepped portion in the direction orthogonal to the axial direction, the distance D1 from point P to intersection U, and the distance D2 from point Q to intersection U are D1≦ A and D2≦B are satisfied.

In the present disclosure, since the height A and width B of the stepped portion, the distance D1 from point P to intersection U, and the distance D2 from point Q to intersection U satisfy D1≦A and D2≦B, Point P does not face the end face of the teeth, and point Q does not face the side faces of the teeth. Therefore, stress concentration in the insulating portion can be suppressed. As a result, the thickness of the insulating portion can be reduced and the circumferential length of the winding can be shortened.

1 is a cross-sectional view showing an electric motor of Embodiment 1. FIG. FIG. 3 is a diagram showing the axial positional relationship between the stator core and rotor core of the first embodiment. FIG. 3 is a plan view showing the stator core of the first embodiment. FIG. 2 is a perspective view showing a split core of Embodiment 1. FIG. FIG. 3 is a perspective view showing a split core and an insulating part in the first embodiment. FIG. 3 is a cross-sectional view showing the teeth and the insulating portion of the first embodiment. FIG. 7 is a cross-sectional view showing another example of the teeth and the insulating portion of the first embodiment. FIG. 3 is an enlarged view showing a stepped portion of the teeth of the first embodiment. Cross-sectional view (A) showing the teeth and the insulating part of Comparative Example 1, (B) a cross-sectional view showing the teeth and the insulating part of Comparative Example 2, and (C) an enlarged view showing the stepped part of the teeth of Comparative Example 2. It is. 5 is a graph showing the relationship between the dimension ratio A/B of the stepped portion and the torque constant in Embodiment 1. FIG. 7 is a graph showing the relationship between the ratio A/L1 of the height A of the stepped portion and the length L1 of the teeth and the rate of change in loss in the first embodiment. FIG. 7 is a diagram showing an axial positional relationship between a stator core and a rotor core according to a second embodiment. FIG. 7 is a cross-sectional view showing teeth and an insulating portion according to a second embodiment. 7 is a diagram showing another example of the axial positional relationship between the stator core and the rotor core according to the second embodiment. FIG. FIG. 7 is a perspective view showing a split core and an insulating part in Embodiment 3; FIG. 7 is a cross-sectional view showing teeth and an insulating part in Embodiment 3. FIG. 7 is a cross-sectional view showing teeth and an insulating portion of Comparative Example 3. FIG. 2 is a longitudinal sectional view showing a compressor to which the electric motor of each embodiment can be applied. FIG. 19 is a diagram showing a refrigeration cycle device to which the compressor of FIG. 18 can be applied.

Embodiment 1.
<Configuration of electric motor>
First, Embodiment 1 will be described. FIG. 1 is a sectional view showing an electric motor 100 according to the first embodiment. The electric motor 100 shown in FIG. 1 is an embedded permanent magnet electric motor, and is used, for example, in the compressor 8 (FIG. 18).

The electric motor 100 includes a rotor 5 having a shaft 65 that is a rotating shaft, and a stator 1 provided so as to surround the rotor 5. An air gap of, for example, 0.3 to 1.0 mm is formed between the stator 1 and the rotor 5. The stator 1 is assembled inside a cylindrical shell 80 of a compressor 8 (FIG. 18), which will be described later.

Hereinafter, the direction of the axis Ax, which is the center of rotation of the rotor 5, will be referred to as the "axial direction." The radial direction centered on the axis Ax is defined as the "radial direction." The circumferential direction centered on the axis Ax is defined as the "circumferential direction."

<Rotor configuration>
The rotor 5 has a cylindrical rotor core 50 centered on the axis Ax, and a permanent magnet 60 attached to the rotor core 50. The rotor core 50 is made by laminating a plurality of electromagnetic steel plates in the axial direction and fixing them by caulking or the like.

The thickness of the electromagnetic steel plate is 0.1 to 0.7 mm. A center hole 53 is formed at the radial center of the rotor core 50. The shaft 65 described above is fixed to the center hole 53 of the rotor core 50 by shrink fitting, press fitting, adhesive, or the like. The rotor core 50 has a circumferential outer periphery centered on the axis Ax.

A plurality of magnet insertion holes 51 into which permanent magnets 60 are inserted are formed along the outer periphery of the rotor core 50. One magnet insertion hole 51 corresponds to one magnetic pole. The circumferential center of the magnet insertion hole 51 corresponds to the pole center. An interpolar portion is defined between adjacent magnet insertion holes 51 . The number of magnet insertion holes 51 is six here. In other words, the number of poles is six. However, the number of poles is not limited to six, but may be two or more.

The magnet insertion hole 51 extends linearly in a direction perpendicular to a straight line passing through the center of the magnet insertion hole 51 in the circumferential direction. However, the magnet insertion hole 51 is not limited to such a shape, and may extend in a V-shape, for example.

One permanent magnet 60 is arranged in each magnet insertion hole 51. The permanent magnet 60 has a flat plate shape, has a width in the circumferential direction of the rotor core 50, and has a thickness in the radial direction. Each permanent magnet 60 is magnetized in the thickness direction.

The permanent magnet 60 is made of, for example, a rare earth magnet. The rare earth magnet is, for example, a neodymium magnet containing neodymium (Nd), iron (Fe), and boron (B). Note that two or more permanent magnets 60 may be arranged in each magnet insertion hole 51.

In the rotor core 50, flux barriers 52, which are holes, are formed at both ends of the magnet insertion hole 51 in the circumferential direction. A thin wall portion is formed between each flux barrier 52 and the outer periphery of the rotor core 50. The width of the thin portion in the radial direction is set, for example, to be the same as the thickness of the electromagnetic steel sheet.

A slit 54 is formed between the magnet insertion hole 51 and the outer periphery of the rotor core 50. The slit 54 is formed to adjust the flow of magnetic flux emitted from the permanent magnet 60. Here, seven slits 54 are formed symmetrically with respect to the circumferential center of the magnet insertion hole 51. However, the number and arrangement of slits 54 are not limited to the example described here. Further, the rotor core 50 does not necessarily have to have the slit 54.

In the rotor core 50, hole portions 57 and 58 are formed radially inside the magnet insertion hole 51. The holes 57 and 58 are used as air holes through which a refrigerant passes or holes through which a jig is inserted. Both of the hole portions 57 and 58 are formed in the same number as the number of poles. The circumferential position of each hole 57 coincides with the circumferential center of the magnet insertion hole 51. The circumferential position of each hole portion 58 coincides with the interpolar portion. However, the number and arrangement of the holes 57 and 58 are not limited to the example described here. Furthermore, the rotor core 50 does not necessarily have to have the holes 57 and 58.

Further, a caulking portion 56 for fixing the electromagnetic steel plate of the rotor core 50 is formed on the radially outer side of each hole portion 58. However, the arrangement of the caulking portion 56 is not limited to the example described here. Furthermore, the electromagnetic steel plates of the rotor core 50 may be fixed by a method other than caulking.

<Stator configuration>
The stator 1 includes a stator core 10 that surrounds a rotor core 50 from the outside in the radial direction, and a winding 30 that is wound around the stator core 10. The stator core 10 is made by laminating a plurality of electromagnetic steel plates in the axial direction and fixing them by caulking or the like. The thickness of the electromagnetic steel plate is 0.1 to 0.7 mm.

The stator core 10 has an annular core back 11 centered on the axis Ax, and a plurality of teeth 12 extending radially inward from the core back 11. The teeth 12 are arranged at regular intervals in the circumferential direction. The number of teeth 12 is nine here. However, the number of teeth 12 is not limited to nine, and may be two or more. A slot 14 is formed between teeth 12 adjacent to each other in the circumferential direction. The number of slots 14 is nine, which is the same as the number of teeth 12.

The winding 30 is made of magnet wire, and is wound around each tooth 12 in a concentrated manner. The outer diameter, ie, wire diameter, of the magnet wire is, for example, 1.0 mm. The number of turns of the winding 30 around one tooth 12 is, for example, 80 turns.

The winding 30 is made of aluminum wire or copper wire. Aluminum wire is particularly desirable because it is softer than copper wire and can be wrapped tightly around the teeth 12. Furthermore, since aluminum wire is cheaper than copper wire, it is advantageous in reducing manufacturing costs.

FIG. 2 is a diagram showing the axial positional relationship between the stator core 10 and the rotor core 50. As shown in FIG. 2, stator core 10 and rotor core 50 are at the same position in the axial direction. That is, both axial end surfaces 10e of stator core 10 are located at the same axial positions as both axial end surfaces 50e of rotor core 50, respectively.

Note that the axial positional relationship between the stator core 10 and the rotor core 50 is not limited to the example shown in FIG. good. A case where the axial center position of stator core 10 and the axial center position of rotor core 50 are different will be described in a second embodiment.

FIG. 3 is a plan view showing the stator core 10. The core back 11 has an inner circumferential surface 11a and an outer circumferential surface. An inner peripheral surface 11a of the core back 11 faces the slot 14. The outer peripheral surface of the core back 11 fits into the shell 80 of the compressor 8 (FIG. 18).

As described above, the teeth 12 extend radially inward from the core back 11. A straight line in the radial direction passing through the circumferential center of each tooth 12 is referred to as a tooth center line T1. The teeth 12 have a pair of side surfaces 12a on both sides in the circumferential direction. Side surfaces 12a of the teeth 12 face the slots 14.

Each tooth 12 also has a tooth tip 13 that faces the rotor 5 (FIG. 1). The tooth tip portion 13 is wider in the circumferential direction than other portions of the teeth 12 and protrudes further than the side surfaces 12a of the teeth 12 in the circumferential direction. An outer surface 13a is formed on the radially outer side of the protruding portion of the tooth tip 13. The outer surface 13a of the tooth tip 13 faces the slot 14.

Although the tooth tip 13 is a part of the tooth 12, it has a different shape from other parts of the tooth 12, so the tooth tip 13 may be explained separately from other parts of the tooth 12.

A stepped portion 12S is formed at the axial end of the teeth 12. The stepped portion 12S is formed on the side surface 12a side of the teeth 12, that is, on the slot 14 side. Therefore, the circumferential width of the teeth 12 is narrower at the axial ends than at the axial center.

A stepped portion 11S is formed at the axial end of the core back 11. The stepped portion 11S is formed on the inner peripheral surface 11a side of the core back 11, that is, on the slot 14 side. Therefore, the radial width of the core back 11 is narrower at the axial ends than at the axial center.

A stepped portion 13S is formed at the axial end of the tooth tip portion 13. The stepped portion 13S is formed on the outer surface 13a side of the tooth tip portion 13, that is, on the slot 14 side. Therefore, the radial width of the protruding portion of the tooth tip 13 is narrower at the axial end than at the axial center.

Furthermore, a dividing surface 15 that divides the stator core 10 is formed on the core back 11. The dividing surface 15 is formed at an intermediate position between two teeth 12 adjacent to each other in the circumferential direction. Furthermore, the dividing surface 15 is formed from the inner circumferential surface 11a of the core back 11 to the outer circumferential surface.

The stator core 10 is divided into nine divided cores 10A each including one tooth 12 by a dividing surface 15. In other words, stator core 10 is configured by combining a plurality of divided cores 10A.

The split core 10A is joined at the split surface 15 by welding or the like. Alternatively, the split cores 10A may be connected to each other by a thin wall portion formed on the outer peripheral side of the split surface 15.

FIG. 4 is a perspective view showing the split core 10A. In FIG. 4, the direction of the axis Ax (FIG. 1), that is, the axial direction, is indicated by an arrow Z. The core back 11 has an end surface 11e facing in the axial direction. The teeth 12 have end faces 12e facing in the axial direction. The tooth tip portion 13 has an end surface 13e facing in the axial direction.

These end surfaces 11e, 12e, and 13e are on the same plane and correspond to the end surface 10e of the stator core 10 shown in FIG. 2. Further, the end surfaces 11e, 12e, and 13e are all surfaces perpendicular to the axial direction.

The stepped portion 12S of the tooth 12 is formed between the end surface 12e and the side surface 12a of the tooth 12. The stepped portion 12S includes a wall surface 12b facing the slot 14 and a bottom surface 12c facing the axial direction. The wall surface 12b is parallel to the axial direction, and the bottom surface 12c is perpendicular to the axial direction.

The step portion 11S of the core back 11 is formed between the end surface 11e of the core back 11 and the inner peripheral surface 11a. The step portion 11S includes a wall surface 11b facing the slot 14 and a bottom surface 11c facing the axial direction. The wall surface 11b is parallel to the axial direction, and the bottom surface 11c is perpendicular to the axial direction.

The stepped portion 13S of the tooth tip 13 is formed between the end surface 13e and the outer surface 13a of the tooth tip 13. The stepped portion 13S includes a wall surface 13b facing the slot 14 and a bottom surface 13c facing the axial direction. The wall surface 13b is parallel to the axial direction, and the bottom surface 13c is perpendicular to the axial direction.

The bottom surfaces 11c, 12c, and 13c of the stepped

portions

11S, 12S, and 13S are located on the same plane. Therefore, the axial heights (height A, which will be described later) of the stepped

portions

11S, 12S, and 13S are the same.

The split core 10A is composed of a first electromagnetic steel sheet 101 laminated at the center in the axial direction, and a second electromagnetic steel sheet 102 laminated at both ends in the axial direction. In the second electromagnetic steel sheet 102, the width of the core back 11, the width of the teeth 12, and the width of the protrusion of the tooth tip 13 are narrower than those of the first electromagnetic steel sheet 101.

FIG. 5 is a perspective view showing the split core 10A and the insulating section 20. An insulating portion 20 is attached to the split core 10A so as to cover the teeth 12 from both sides in the axial direction and both sides in the circumferential direction. The insulating section 20 is made of resin such as polybutylene terephthalate (PBT) or liquid crystal polymer (LCP), for example.

The insulating part 20 has a body part 22 that covers the teeth 12, a wall part 21 arranged on the radially outer side of the body part 22, and a flange part 23 arranged on the radially inner side of the body part 22. The wall portion 21 and the flange portion 23 face each other in the radial direction with the body portion 22 in between.

The wall portion 21 is provided to cover the inner circumferential surface 11a of the core back 11, and further protrudes to both sides in the axial direction. The wall portion 21 has an engaging portion 21a that engages with the stepped portion 11S of the core back 11.

The body portion 22 is provided to cover the end surface 12e and side surface 12a (FIG. 4) of the teeth 12. The body portion 22 has an engaging portion 22a (FIG. 6) that engages with the stepped portion 12S (FIG. 4) of the teeth 12.

The flange portion 23 is provided so as to cover the end surface 13e (FIG. 4) and the outer surface 13a of the tooth tip portion 13. The flange portion 23 has an engaging portion 23a that engages with the stepped portion 13S of the tooth tip portion 13.

A winding 30 is wound around the body 22. The wall portion 21 and the flange portion 23 guide the winding 30 wound around the body portion 22 from both sides in the radial direction.

The insulating portion 20 is formed, for example, by integrally molding resin with the split core 10A. The insulating section 20 may also be formed by attaching a resin molded body to the split core 10A.

Although the insulating section 20 that is integrally constructed will be described here, it may be constructed of an insulator and an insulating film. This will be explained in the third embodiment.

FIG. 6 is a cross-sectional view of the teeth 12 and the insulating portion 20 in a plane perpendicular to the direction in which the teeth 12 extend. The extending direction of the teeth 12 refers to a radial straight line passing through the circumferential center of the teeth 12, that is, the direction of the teeth center line T1 (FIG. 3).

The teeth 12 have a length L1 in the axial direction. The length L1 is the distance between both end surfaces 12e of the teeth 12. Moreover, the teeth 12 have a width W1 at the center in the axial direction, and a width W2 at the end in the axial direction where the step portion 12S is formed. The width W1 is the distance between both side surfaces 12a of the teeth 12. The width W2 is the distance between the wall surfaces 12b of the two stepped portions 12S of the teeth 12. The widths W1 and W2 have a relationship of W1>W2.

The insulating portion 20 has a first surface 201 that is a plane that covers the end surface 12e of the tooth 12, a second surface 202 that is a plane that faces the slot 14, and a second surface that extends from the first surface 201 to the second surface 202. and a third surface 203 that is a curved surface or an inclined surface.

The first surface 201 is a plane extending in a plane perpendicular to the axial direction, and faces the end surface 12e of the teeth 12. The second surface 202 is a plane extending in a plane parallel to the axial direction, and faces the side surface 12a of the teeth 12.

The third surface 203 is a curved surface that connects the first surface 201 and the second surface 202 in a curve, or a curved surface that connects the first surface 201 and the second surface 202 in a plane perpendicular to the extending direction of the teeth 12. This is an inclined surface that linearly connects the surface 202. Although the case where the third surface 203 is a curved surface will be described below, it may be an inclined surface.

The axial dimension of the stepped portion 12S is defined as height A. This height A corresponds to the distance from the bottom surface 12c of the stepped portion 12S to the end surface 12e of the teeth 12.

In the plane orthogonal to the extending direction of the teeth 12, the dimension of the stepped portion 12S in the direction orthogonal to the axial direction is defined as width B. This width B corresponds to the distance from the wall surface 12b of the stepped portion 12S to the side surface 12a of the tooth 12.

In the example shown in FIG. 6, the height A and width B of the stepped portion 12S of the teeth 12 have a relationship of A≧B. An example is A=B. In this case, the third surface 203 extends in an arc shape.

However, the shape of the teeth 12 is not limited to the shape shown in FIG. 6. For example, as shown in FIG. 7, the height A and width B of the stepped portion 12S of the teeth 12 may have a relationship of A>B. In this case, the third surface 203 extends in the axial direction to form a long elliptical arc.

FIG. 8 is an enlarged view showing the periphery of the stepped portion 12S of the teeth 12. The first surface 201 of the insulating portion 20 covers the end surface 12e of the tooth 12 and further extends to the stepped portion 12S. The second surface 202 of the insulating portion 20 covers the side surface 12a of the tooth 12 and further extends to the stepped portion 12S.

A point P is the boundary between the first surface 201 and the third surface 203 on a surface perpendicular to the extending direction of the teeth 12. Further, a point that forms the boundary between the second surface 202 and the third surface 203 is defined as a point Q.

The distance in the axial direction between point P and point Q is defined as distance D1. The distance between point P and point Q in the direction perpendicular to the axial direction is defined as distance D2. That is, if U is the intersection of a first straight line L1 that passes through point P and is parallel to the axial direction and a second straight line L2 that passes through point Q and is perpendicular to the axial direction, then distance D1 is from point P to intersection U. The distance D2 corresponds to the distance from the point Q to the intersection U.

The height A and width B of the stepped portion 12S and the distances D1 and D2 satisfy D1≦A and D2≦B. That is, point P does not oppose the end surface 12e of the tooth 12, and point Q does not oppose the side surface 12a of the tooth 12. Therefore, the insulating portion 20 does not have any locally thinned portions.

<Effect>
The effect of the first embodiment will be explained in comparison with a comparative example. FIG. 9(A) is a cross-sectional view showing the teeth 121 and the insulating portion 20C of Comparative Example 1. FIG. 9(B) is a cross-sectional view showing the teeth 122 and the insulating portion 20D of Comparative Example 2.

The teeth 121 of Comparative Example 1 shown in FIG. 9(A) do not have a stepped portion at the axial end. That is, a 90 degree corner is formed between the end surface 12e and the side surface 12a. The insulating portion 20C has a first surface 201 that covers the end surface 12e of the tooth 121, a second surface 202 facing the slot 14, and a third surface 203 between these

surfaces

201 and 202. The third surface 203 faces the corner.

In order to wind the winding 30 around the insulating part 20C without causing a bulge, it is desirable that the radius of curvature of the third surface 203 is large. However, in order to increase the radius of curvature of the third surface 203, it is necessary to increase the thickness t1 from the end surface 12e of the teeth 121 to the first surface 201 of the insulating portion 20C. Increasing the thickness t1 increases the circumferential length of the winding 30, and as the circumferential length of the winding 30 increases, copper loss increases.

The tooth 122 of Comparative Example 2 shown in FIG. 9(B) has a stepped portion 12S between the end surface 12e and the side surface 12a. The insulating portion 20D has a first surface 201 that covers the end surface 12e of the tooth 122, a second surface 202 facing the slot 14, and a third surface 203 between these

surfaces

201 and 202. The third surface 203 faces the stepped portion 12S.

Since the teeth 122 have the stepped portions 12S, the thickness t1 from the end surface 12e of the teeth 122 to the first surface 201 of the insulating portion 20D is reduced while increasing the radius of curvature of the third surface 203 of the insulating portion 20D. be able to.

FIG. 9(C) is an enlarged view showing the periphery of the stepped portion 12S of the teeth 122 of Comparative Example 2. In Comparative Example 2, a point P, which is the boundary between the first surface 201 and the third surface 203, is located at a position opposite to the end surface 12e of the tooth 122 on a surface perpendicular to the extending direction of the tooth 122. Further, a point Q, which is the boundary between the second surface 202 and the third surface 203, is located at a position opposite to the side surface 12a of the teeth 122.

That is, the distance D1 in the axial direction between the point P and the point Q, the distance D2 in the direction perpendicular to the axial direction between the point P and the point Q, the height A in the axial direction of the stepped portion 12S, and the height A of the stepped portion 12S in the axial direction. The width B in the direction perpendicular to the axial direction satisfies D1>A and D2>B.

In this case, between the third surface 203 and the end surface 12e of the teeth 12, a thin portion is created as shown by the symbol M. Similarly, between the third surface 203 and the side surface 12a of the teeth 12, a thin portion as indicated by the symbol N is generated.

If such a thin portion occurs, the insulating portion 20D is likely to be damaged. In order to prevent damage to the insulating portion 20D, it is necessary to increase the thickness t1 from the end surface 12e to the first surface 201. Therefore, the thickness t1 increases and the circumferential length of the winding 30 increases, making it difficult to reduce copper loss.

On the other hand, in the first embodiment, as shown in FIG. 8, the distance D1 in the axial direction between the point P and the point Q, the distance D2 in the direction orthogonal to the axial direction between the point P and the point Q, The height A of the stepped portion 12S and the width B of the stepped portion 12S satisfy D1≦A and D2≦B. That is, point P does not oppose the end surface 12e of the tooth 12, and point Q does not oppose the side surface 12a of the tooth 12.

Therefore, even if the radius of curvature of the third surface 203 of the insulating section 20 is increased, no portion where the thickness is locally thinned occurs. Therefore, even if the thickness t1 from the end surface 12e of the teeth 12 to the first surface 201 of the insulating section 20 is made thin, the insulating section 20 can be prevented from being damaged. Thereby, the radius of curvature of the third surface 203 can be increased to suppress the bulge of the winding 30, and the thickness t1 can be reduced to shorten the circumferential length of the winding 30. As a result, copper loss can be effectively reduced.

Next, the relationship between the height A and the width B of the stepped portion 12S will be explained. FIG. 10 is a graph showing the relationship between the dimensional ratio A/B, which is the ratio of the height A to the width B, and the torque constant of the electric motor 100. The torque constant is the torque generated per unit current.

The torque constant of the electric motor 100 is determined by the ratio ((A×B)/(L1×W1) of the cross-sectional area (A×B) of the stepped portion 12S to the cross-sectional area (L1×W1) of the teeth 12 without the stepped portion 12S. ) is the value obtained by performing an analysis by changing the height A and width B of the stepped portion 12S so that the height A and the width B are constant.

As shown in FIG. 10, as the value of A/B increases, the torque constant increases. The reason is as follows.

A core portion sandwiched between an end surface 12e and wall surfaces 12b on both sides thereof is formed at the axial end of the tooth 12. The wider the width B of the stepped portion 12S, the narrower the width of the core portion, which makes magnetic saturation more likely to occur, and therefore makes it more difficult for the magnetic flux of the rotor 5 to flow into the teeth 12. As the width B of the stepped portion 12S becomes narrower, the width of the core portion becomes wider, which makes it difficult for magnetic saturation to occur, and therefore, it becomes easier for the magnetic flux of the rotor 5 to flow into the teeth 12.

If the cross-sectional area of the stepped portion 12S is constant, the width B decreases as the height A of the stepped portion 12S increases. As described above, as the width B decreases, magnetic saturation becomes less likely to occur, so it becomes easier for the magnetic flux of the rotor 5 to flow into the teeth 12, and as a result, the generated torque increases. Therefore, the larger the value of A/B, the larger the torque constant.

Since the torque constant increases as the value of A/B increases, it can be seen that, for example, the case where A/B>1 is preferable to the case where A/B≦1. That is, as shown in FIG. 7, the height A and width B of the stepped portion 12S satisfy A>B rather than the configuration in which the height A and the width B of the stepped portion 12S satisfy A≦B as shown in FIG. It can be seen that the configuration that satisfies B is preferable.

Next, the relationship between the axial height A of the stepped portion 12S and the axial length L1 of the teeth 12 will be described. FIG. 11 is a graph showing the relationship between the ratio A/L1 of the axial height A of the stepped portion 12S to the axial length L1 of the teeth 12 and the rate of change in iron loss and copper loss.

The values of iron loss and copper loss are determined by the ratio ((A×B)/(L1× This value was obtained by performing an analysis while changing the height A and width B so that W1)) was constant. Further, the values of iron loss and copper loss are expressed as relative values to the values of iron loss and copper loss when the teeth 12 do not have the stepped portion 12S.

As shown in FIG. 11, as the value of A/L1 increases, copper loss decreases and iron loss increases. The reason why the copper loss decreases as the value of A/L1 increases is that if the cross-sectional area (A x B) of the stepped portion 12S is constant, as the height A of the stepped portion 12S increases (that is, the width B decreases). This is because by suppressing magnetic saturation, the magnetic flux from the rotor 5 becomes easier to flow in, and the current value can be reduced accordingly.

Also, the reason why the iron loss increases as the value of A/L1 increases is that as the ratio of the height A of the stepped portion 12S to the length L1 of the teeth 12 increases, the narrower width of the teeth 12 increases. This is because the ratio increases, and the magnetic resistance of the teeth 12 as a whole increases.

From FIG. 11, compared to the case where the teeth 12 do not have the stepped portion 12S, the increase rate of iron loss and the decrease rate of copper loss are the same when A/L1=0.157. That is, when A/L1=0.157, the copper loss increases by 0.7% and the iron loss also increases by 0.7% compared to the case where the teeth 12 do not have the step portion 12S.

When A/L1<0.157, the increase in copper loss is greater than the increase in iron loss compared to the case where the teeth 12 do not have the stepped portion 12S. When A/L1>0.157, the increase in iron loss is greater than the increase in copper loss compared to the case where the teeth 12 do not have the stepped portion 12S.

In this embodiment, since the copper loss can be reduced by preventing the winding 30 from bulging, the range of A/L1≦0.157 in which the increase in iron loss is the same as or smaller than the increase in copper loss is desirable.

The electric motor 100 used in the compressor is designed according to the required specifications of the compressor, but the shape of the stator core 10 is common, and the width of the core back 11 or teeth 12, the number of turns of the winding 30, etc. It is desirable to respond to various required specifications through adjustment. In this embodiment, copper loss and iron loss can be reduced due to the shape of stator core 10 described above, so it is possible to realize a highly efficient electric motor 100 that meets various required specifications.

Next, the relationship between the core back 11, the teeth 12, and the

step portions

11S, 12S, and 13S of the tooth tips 13 will be described. As shown in FIG. 4, the core back 11 has a stepped portion 11S, the teeth 12 has a stepped portion 12S, and the tooth tip portion 13 has a stepped portion 13S.

The stepped portion 11S of the core back 11 has a width E1 in the radial direction centered on the axis Ax (FIG. 1). The width E1 corresponds to the amount of displacement in the radial direction of the wall surface 11b of the stepped portion 11S from the inner circumferential surface 11a of the core back 11.

The stepped portion 13S of the tooth tip portion 13 has a width E2 in the radial direction centered on the axis Ax. The width E2 corresponds to the amount of displacement in the radial direction of the wall surface 13b of the stepped portion 13S from the outer surface 13a of the tooth tip portion 13. Further, the stepped portion 12S of the teeth 12 has a width B as described above.

A winding 30 is wound around the body part 22 of the insulating part 20 that covers the teeth 12. On the other hand, the winding 30 is not wound around the wall portion 21 attached to the core back 11 and the flange portion 23 attached to the tooth tip portion 13. Therefore, the width B of the stepped portion 12S of the teeth 12 is related to the winding swell state of the winding 30, but the widths E1 and E2 of the stepped

portions

11S and 13S of the core back 11 and the tooth tip 13 are related to the winding swell state of the winding 30. Not related to condition.

Therefore, the width B of the stepped portion 12S of the teeth 12 is preferably wider than the width E1 of the stepped portion 11S of the core back 11, and also wider than the width E2 of the stepped portion 13S of the tooth tip 13. That is, it is desirable that B>E1 and B>E2 hold true. Thereby, the magnetic resistance at the core back 11 and the tooth tip portion 13 can be reduced while suppressing the winding 30 wound around the teeth 12 from expanding.

Although an example in which the stator core 10 is configured with a plurality of divided cores 10A has been described here, the stator core 10 is not limited to such a configuration. That is, the stator core 10 may be an integral core formed by stacking annularly punched electromagnetic steel plates in the axial direction.

Although an example in which the step portions 12S are formed on both circumferential sides of the teeth 12 has been described here, the step portions 12S may be formed on at least one side of the teeth 12 in the circumferential direction. Moreover, although the stepped

portions

11S and 13S are provided in the core back 11 and the tooth tip portion 13 here, these stepped

portions

11S and 13S do not necessarily need to be provided.

<Effects of the embodiment>
As described above, the stator 1 of the first embodiment includes the core back 11 and the teeth 12, and the winding 30 is wound around the teeth 12 via the insulating part 20. The teeth 12 have an end surface 12e facing in the axial direction, a side surface 12a facing the slot 14, and a stepped portion 12S formed between the end surface 12e and the side surface 12a. The insulating section 20 includes a first surface 201 that covers the end surface 12e of the teeth 12, a second surface 202 facing the slot 14, and a curved or inclined surface extending from the first surface 201 to the second surface 202. and a third surface 203 which is a surface. In a cross section perpendicular to the extending direction of the teeth 12, the boundary between the first surface 201 and the third surface 203 of the insulating section 20 is defined as a point P, and the boundary between the second surface 202 and the third surface 203 is defined as a point P. Let the point Q be a point of intersection between a first straight line L1 passing through the point P and parallel to the axial direction and a second straight line L2 passing through the point Q and orthogonal to the axial direction. The height A of the stepped portion 12S in the axial direction, the width B of the stepped portion 12S in the direction perpendicular to the axial direction, the distance D1 from the point P to the intersection U, and the distance D2 from the point Q to the intersection U are: D1≦A and D2≦B are satisfied.

With this configuration, the point P of the insulating part 20 does not face the end surface 12e of the tooth 12, and the point Q of the insulating part 20 does not face the side surface 12a of the tooth 12. Therefore, even if the radius of curvature of the third surface 203 of the insulating section 20 is increased, no portion where the thickness is locally thinned occurs, and stress concentration can be suppressed. This allows the thickness of the insulating section 20 to be reduced while preventing the winding 30 from bulging. That is, the circumferential length of the winding 30 can be shortened and copper loss can be reduced.

In addition, since the height A and width B of the stepped portion 12S satisfy A>B, magnetic saturation is less likely to occur within the teeth 12, and the magnetic flux of the rotor 5 easily flows into the teeth 12, so the torque constant is increased. can do.

In addition, since the axial height A of the stepped portion 12S and the axial length L1 of the stator core 10 satisfy A/L1≦0.157, increases in iron loss and copper loss in the teeth 12 can be suppressed. can.

Further, the insulating portion 20 is integrally formed with a portion that covers the end surface 12e of the teeth 12, a portion that covers the side surface 12a, and a portion that covers the stepped portion 12S. Therefore, the insulating portion 20 can be formed in a simple process by integral molding using resin, for example.

Furthermore, since the winding 30 is made of aluminum wire, the winding 30 can be tightly wound around the teeth 12 by utilizing the softness of the aluminum wire. Aluminum wire has a higher electrical resistance than copper wire, but in this embodiment, the circumference of the winding 30 can be shortened, so even when aluminum wire is used, increase in copper loss can be avoided. Can be suppressed.

Embodiment 2.
Next, a second embodiment will be described. In the first embodiment, the step portions 12S are formed at both ends of the stator 1 in the axial direction. In contrast, in the second embodiment, the stepped portion 12S is formed only at one end of the stator 1 in the axial direction.

FIG. 12 is a diagram showing the relationship between the stator core 10 and rotor core 50 of the electric motor according to the second embodiment. In FIG. 12, in the axial direction, the direction of the compressor 8 toward the compression mechanism 9 (FIG. 18) is shown as a -Z direction, and the opposite direction is shown as a +Z direction. Note that in FIG. 12, the +Z direction is upward and the -Z direction is downward, but the present invention is not limited thereto.

The +Z direction end surface 50e of the rotor core 50 is located further in the +Z direction than the +Z direction end surface 10e of the stator core 10. An end face 50e of the rotor core 50 in the −Z direction is located further in the +Z direction than an end face 10e of the stator core 10 in the −Z direction.

In other words, the rotor core 50 protrudes more than the stator core 10 in the +Z direction. That is, the axial center position of rotor core 50 is displaced in the +Z direction from the axial center position of stator core 10 .

Therefore, a magnetic attraction force acts between the stator core 10 and the rotor core 50 in a direction that causes the center positions of the two to approach each other in the axial direction. This magnetic attraction force urges the rotor 5 in the −Z direction, that is, toward the compression mechanism 9, and vibrations of the rotor 5 are suppressed.

The stepped portion 12S is not formed at the end of the teeth 120 in the +Z direction in the second embodiment. On the other hand, a stepped portion 12S is formed at the end of the teeth 120 in the −Z direction. The shape and dimensions of the stepped portion 12S are as described in the first embodiment.

The axial length of the stepped portion 12S of the teeth 120 is the height A, as described in the first embodiment. Of the core region R1 having a height A in the axial direction from the -Z direction end surface 10e of the stator core 10, the axial length of the region facing the rotor core 50 is defined as L1.

Similarly, among the core region R2 having a height A in the axial direction from the end surface 10e in the +Z direction of the stator core 10, the axial length of the region facing the rotor core 50 is defined as L2. Note that the core region R1 is also referred to as a first region, and the core region R2 is also referred to as a second region.

In the core regions R1 and R2 of the stator core 10, the lengths L1 and L2 of the regions facing the rotor core 50 satisfy L1<L2. In other words, when core regions R1 and R2 of the same height A are defined at both ends of the stator core 10 in the axial direction, the ratio of the region facing the rotor core 50 in the core regions R1 and R2 is small. formed on the side.

In the core region R2 of the stator core 10, since the proportion of the region facing the rotor core 50 is large, a larger amount of magnetic flux from the rotor 5 flows into the core region R2. Therefore, when the stepped portion 12S is provided in the core region R2 of the teeth 120, magnetic saturation is likely to occur, and iron loss may increase.

Therefore, in the second embodiment, the step portion 12S is provided in the teeth 120 only in the core region R1 where there is little inflow magnetic flux from the rotor core 50. That is, the stepped portion 12S is provided in the teeth 120 only at the end of the stator core 10 in the −Z direction. Further, although not shown, the stepped portion 11S of the core back 11 and the stepped portion 13S of the tooth tip portion 13 are also provided only at the end of the stator core 10 in the −Z direction.

FIG. 13 is a cross-sectional view of the teeth 120 and the insulating portion 20A of the second embodiment in a plane perpendicular to the extending direction of the teeth 120. As shown in FIG. 13, a stepped portion 12S is provided at the end of the teeth 120 in the −Z direction. The shape and dimensions of the stepped portion 12S are as described in the first embodiment.

On the other hand, the step portion 12S is not provided at the end of the teeth 120 in the +Z direction. Therefore, a 90 degree corner is formed between the +Z direction end surface 12e and side surface 12a of the teeth 120.

The insulating portion 20A includes a first surface 201 that covers the end surface 12e of the tooth 120, a second surface 202 facing the slot 14, and a third surface extending from the first surface 201 to the second surface 202. 203. The thickness t1 from the end surface 12e of the teeth 120 to the first surface 201 of the insulating portion 20A is longer at the end in the +Z direction than at the end in the −Z direction.

Except for the above-mentioned points, the electric motor of Embodiment 2 is configured similarly to electric motor 100 of Embodiment 1.

As described above, in the second embodiment, there is a step in the teeth 120 at the end where the opposing area with the rotor core 50 is smaller when the axial length is the same among both axial ends of the stator core 10. A section 12S is provided. Therefore, while suppressing magnetic saturation in the teeth 120, the circumferential length of the winding 30 can be shortened and copper loss can be reduced.

Variation example.
FIG. 14 is a diagram showing the relationship between stator core 10 and rotor core 50 in a modification of the second embodiment. In the modified example, the rotor core 50 protrudes from the stator core 10 on both sides in the axial direction, that is, in the +Z direction and the -Z direction. However, the protrusion amount Z2 of the rotor core 50 in the +Z direction is larger than the protrusion amount Z1 in the -Z direction.

With this configuration in which the rotor core 50 protrudes from the stator core 10 on both sides in the axial direction, the axial length of the stator core 10 can be shortened and the material cost of the stator core 10 can be reduced.

On the other hand, magnetic flux from the protruding portion of the rotor core 50 also flows into the stator core 10 . Therefore, more magnetic flux from the rotor core 50 flows into the +Z-direction end of the stator core 10 than at the -Z-direction end of the stator core 10.

Therefore, in the modified example, the stepped portions 12S are provided in the teeth 120 only at the ends in the -Z direction of the stator core 10 where there is less magnetic flux flowing in from the rotor core 50. Further, although not shown, the stepped portion 11S of the core back 11 and the stepped portion 13S of the tooth tip portion 13 are also provided only at the end of the stator core 10 in the −Z direction.

Also in this modification, as in the second embodiment, the circumferential length of the winding 30 can be shortened and copper loss can be reduced while suppressing magnetic saturation in the teeth 120.

Embodiment 3.
Next, Embodiment 3 will be described. FIG. 15 is a perspective view showing the teeth 12 and the insulating portion 20B of the third embodiment. The insulating section 20B of the third embodiment includes an insulator 25 that covers the end surface 12e of the tooth 12, and an insulating film 26 that covers the side surface 12a of the tooth 12. Specifically, insulators 25 are provided on both sides of the teeth 12 in the axial direction, and insulating films 26 are provided on both sides of the teeth 12 in the circumferential direction.

Each insulator 25 is made of a resin such as polybutylene terephthalate (PBT) or liquid crystal polymer (LCP), for example. Each insulating film 26 is, for example, a film formed of a resin such as polyethylene terephthalate (PET). The thickness of the insulating film 26 is, for example, 0.35 mm.

Each insulator 25 has a wall portion 27 attached to the core back 11 , a body portion 28 attached to the teeth 12 , and a flange portion 29 attached to the tooth tips 13 .

The wall portion 27 engages with the stepped portion 11S of the core back 11 and further protrudes in the axial direction. A portion of the wall portion 27 that engages with the stepped portion 11S of the core back 11 is referred to as an engaging portion 27a.

The body portion 28 covers the end surface 12e of the tooth 12 and engages with the stepped portion 12S of the tooth 12. A portion of the body portion 28 that engages with the stepped portion 11S of the core back 11 is referred to as an engaging portion 28a. The body 28 has a first surface 201 facing in the axial direction, a second surface 202 facing the slot 14, and a third surface 203 extending from the first surface 201 to the second surface 202. have

The flange portion 29 covers the end surface 13e of the tooth tip portion 13 and engages with the stepped portion 13S of the tooth tip portion 13. A portion of the flange portion 29 that engages with the stepped portion 13S of the tooth tip portion 13 is referred to as an engaging portion 29a.

The insulator 25 also has an extending portion 24 that extends radially outward from the wall portion 21. The extension portion 24 has a protrusion 24 a that fits into the fitting hole 16 formed in the core back 11 . By fitting the protrusion 24a into the fitting hole 16, the insulator 25 is fixed to the split core 10A. Note that the insulator 25 does not necessarily need to be provided with the protrusion 24a.

The insulating film 26 is provided to cover the inner peripheral surface 11a of the core back 11, the side surface 12a of the tooth 12, and the outer surface 13a of the tooth tip 13. In other words, the insulating film 26 is provided to cover the inner surface of the slot 14.

A winding 30 is wound around the body 28 and the insulating film 26 of the insulator 25. Further, the wall portion 27 and the flange portion 29 of the insulator 25 guide the winding 30 from both sides in the radial direction.

FIG. 16 is a cross-sectional view of the teeth 12 and the insulating portion 20B of the third embodiment in a plane perpendicular to the extending direction of the teeth 12. Since the insulating section 20B of the third embodiment is formed of the insulator 25 and the insulating film 26 made of different materials, it is necessary to ensure an insulating distance from the stator core 10 to the winding 30. Insulation distance is the shortest distance between conductors measured along the surface of an insulator, and is also referred to as creepage distance.

The insulating film 26 further protrudes from the side surface 12a of the teeth 12 in the axial direction. In other words, the insulating film 26 extends not only to cover the side surface 12a of the teeth 12 but also to partially cover the second surface 202 of the insulator 25.

The amount of axial protrusion of the stepped portion 12S of the insulating film 26 from the bottom surface 12c is defined as D. The amount D of protrusion of the insulating film 26 is set to be equal to or greater than the creepage distance from the stator core 10 to the winding 30. The insulation distance is, for example, 2.5 mm.

FIG. 17 is a cross-sectional view of the teeth 121 and the insulating portion 20E of Comparative Example 3. Teeth 121 of Comparative Example 3 does not have a stepped portion. The insulating portion 20E includes an insulator 25 that covers the end surface 12e of the tooth 121, and an insulating film 26 that covers the side surface 12a of the tooth 121.

The insulating film 26 is provided so as to protrude from the end surface 12e of the teeth 121 in the axial direction. Let D be the amount of axial protrusion of the insulating film 26 from the end surface 12e of the teeth 121. The amount of protrusion D is greater than or equal to the above-mentioned insulation distance.

If the insulating film 26 protrudes beyond the insulating portion 20E in the axial direction, the insulating film 26 may be bent inside the slot 14 when winding the winding 30. Therefore, the thickness t1 from the end surface 12e of the teeth 121 to the first surface 201 of the insulating portion 20E must be greater than or equal to the protrusion amount D, which increases the thickness t1.

In contrast, in the third embodiment, since the teeth 12 have the stepped portions 12S, even if the insulating film 26 protrudes by the protrusion amount D from the bottom surface 12c of the stepped portions 12S, the first The thickness t1 up to the surface 201 can be made thinner. Thereby, the circumferential length of the winding 30 can be shortened.

As described above, in Embodiment 3, the teeth 12 have the stepped portions 12S, and the insulating portions 20 have the insulating films 26 that cover the side surfaces 12a of the teeth 12. Therefore, while ensuring the insulation distance, the windings 30 It is possible to shorten the circumferential length and reduce copper loss.

<Compressor>
Next, the compressor 8 using the electric motor 100 will be explained. FIG. 18 is a sectional view showing the configuration of the compressor 8. As shown in FIG. The compressor 8 is a rotary compressor here, and transmits power between the shell 80, the compression mechanism 9 disposed in the shell 80, an electric motor 100 that drives the compression mechanism 9, and the electric motor 100 and the compression mechanism 9. and a shaft 90 that can be connected to each other. The shaft 90 is the shaft 65 shown in FIG. 1 etc., and fits into the center hole 53 of the rotor 5 of the electric motor 100.

The shell 80 is a closed container made of, for example, a steel plate, and covers the electric motor 100 and the compression mechanism 9. Shell 80 has an upper shell 80a and a lower shell 80b. The upper shell 80a includes a glass terminal 81 as a terminal section for supplying power to the electric motor 100 from the outside of the compressor 8, and a discharge pipe 85 for discharging the refrigerant compressed in the compressor 8 to the outside. is installed. The electric motor 100 and the compression mechanism 9 are housed in the lower shell 80b.

The compression mechanism 9 has an annular first cylinder 91 and a second cylinder 92 along a shaft 90. The first cylinder 91 and the second cylinder 92 are fixed to the inner circumference of the shell 80 (lower shell 80b). An annular first piston 93 is arranged on the inner circumferential side of the first cylinder 91, and an annular second piston 94 is arranged on the inner circumferential side of the second cylinder 92. The first piston 93 and the second piston 94 are rotary pistons that rotate together with the shaft 90.

A partition plate 97 is provided between the first cylinder 91 and the second cylinder 92. The partition plate 97 is a disc-shaped member having a through hole in the center. The cylinder chambers of the first cylinder 91 and the second cylinder 92 are provided with vanes (not shown) that divide the cylinder chambers into a suction side and a compression side. The first cylinder 91, the second cylinder 92, and the partition plate 97 are fixed together with bolts 98.

An upper frame 95 is arranged above the first cylinder 91 so as to close the upper side of the cylinder chamber of the first cylinder 91. A lower frame 96 is arranged below the second cylinder 92 so as to close the lower side of the cylinder chamber of the second cylinder 92. Upper frame 95 and lower frame 96 rotatably support shaft 90.

At the bottom of the lower shell 80b of the shell 80, refrigerating machine oil (not shown) for lubricating each sliding part of the compression mechanism 9 is stored. Refrigerating machine oil rises in a hole 90a formed in the axial direction inside the shaft 90, and is supplied to each sliding portion from oil supply holes 90b formed at a plurality of locations on the shaft 90.

The stator 1 of the electric motor 100 is attached to the inside of the shell 80 by shrink fitting. Power is supplied to the winding 30 of the stator 1 from a glass terminal 81 attached to the upper shell 80a. A shaft 90 is fixed to the center hole 53 (FIG. 1) of the rotor 5.

An accumulator 87 that stores refrigerant gas is attached to the shell 80. The accumulator 87 is held, for example, by a holding portion 80c provided on the outside of the lower shell 80b. A pair of

suction pipes

88 and 89 are attached to the shell 80, and refrigerant gas is supplied from the accumulator 87 to the

cylinders

91 and 92 via the

suction pipes

88 and 89.

As the refrigerant, for example, R410A, R407C, or R22 may be used, but from the viewpoint of preventing global warming, it is desirable to use a refrigerant with a low GWP (global warming potential). As the low GWP refrigerant, for example, the following refrigerants can be used.

(1) First, a halogenated hydrocarbon having a carbon double bond in its composition, such as HFO (Hydro-Fluoro-Orefin)-1234yf (CF ₃ CF=CH ₂ ), can be used. GWP of HFO-1234yf is 4.
(2) Additionally, a hydrocarbon having a carbon double bond in its composition, such as R1270 (propylene), may also be used. The GWP of R1270 is 3, lower than that of HFO-1234yf, but the flammability is higher than that of HFO-1234yf.
(3) Also, a mixture containing at least either a halogenated hydrocarbon having a carbon double bond in its composition or a hydrocarbon having a carbon double bond in its composition, for example, a mixture of HFO-1234yf and R32. May be used. Since the above-mentioned HFO-1234yf is a low-pressure refrigerant, it tends to have a large pressure drop, which may lead to a decrease in the performance of the refrigeration cycle (particularly the evaporator). Therefore, it is practically preferable to use a mixture with R32 or R41, which is a higher pressure refrigerant, than HFO-1234yf.

The basic operation of the compressor 8 is as follows. Refrigerant gas supplied from the accumulator 87 is supplied to each cylinder chamber of the first cylinder 91 and the second cylinder 92 through

suction pipes

88 and 89. When the electric motor 100 is driven and the rotor 5 rotates, the shaft 90 rotates together with the rotor 5. Then, the first piston 93 and the second piston 94 that fit into the shaft 90 rotate eccentrically within each cylinder chamber, compressing the refrigerant within each cylinder chamber. The compressed refrigerant passes through the holes 57 and 58 (FIG. 1) of the rotor 5, rises within the shell 80, and is discharged to the outside from the discharge pipe 85.

Note that the compressor in which the electric motor 100 is used is not limited to a rotary compressor, and may be, for example, a scroll compressor.

The electric motor 100 of each embodiment has high motor efficiency due to the reduction in copper loss in the winding 30, so the operating efficiency of the compressor 8 can be improved.

<Refrigerating cycle equipment>
Next, a refrigeration cycle apparatus 400 having the compressor 8 shown in FIG. 18 will be described. FIG. 19 is a diagram showing a refrigeration cycle device 400. The refrigeration cycle device 400 is, for example, an air conditioner, but is not limited to this, and may be, for example, a refrigerator.

The refrigeration cycle device 400 shown in FIG. 19 includes a compressor 401, a condenser 402 that condenses refrigerant, a pressure reducing device 403 that reduces the pressure of the refrigerant, and an evaporator 404 that evaporates the refrigerant. Compressor 401, condenser 402, and pressure reducing device 403 are provided in outdoor unit 410, and evaporator 404 is provided in indoor unit 420.

The compressor 401, condenser 402, pressure reducing device 403, and evaporator 404 are connected by a refrigerant pipe 407, and constitute a refrigerant circuit. Compressor 401 is comprised of compressor 8 shown in FIG. The refrigeration cycle device 400 also includes an outdoor blower 405 facing the condenser 402 and an indoor fan 406 facing the evaporator 404.

The operation of the refrigeration cycle device 400 is as follows. The compressor 401 compresses the sucked refrigerant and sends it out as high-temperature, high-pressure refrigerant gas. The condenser 402 exchanges heat between the refrigerant sent out from the compressor 401 and the outdoor air sent by the outdoor blower 405, condenses the refrigerant, and sends it out as a liquid refrigerant. The pressure reducing device 403 expands the liquid refrigerant sent out from the condenser 402 and sends it out as a low-temperature, low-pressure liquid refrigerant.

The evaporator 404 exchanges heat between the low-temperature, low-pressure liquid refrigerant sent out from the pressure reducing device 403 and indoor air, evaporates the refrigerant, and sends it out as refrigerant gas. The air from which heat has been removed by the evaporator 404 is supplied indoors by the indoor blower 406.

Since the electric motor 100 described in each embodiment can be applied to the compressor 401 of the refrigeration cycle device 400, the operating efficiency of the refrigeration cycle device 400 can be improved.

Although the preferred embodiments have been specifically described above, the present disclosure is not limited to the above embodiments, and various improvements and modifications can be made.

1 stator, 20, 20A, 20B insulation part, 5 rotor, 8 compressor, 9 compression mechanism, 10 stator core, 10A split core, 11 core back, 11S step part, 12, 120 teeth, 12S step, 12a side, 12e End face, 13 tooth tip, 13S step, 14 slot, 15 dividing surface, 21 wall, 22 body, 23 flange, 25 insulator, 26 insulating film, 30 winding, 5 0 Rotor core, 51 Magnet insertion hole, 60 Permanent magnet, 65 shaft, 80 shell, 100 electric motor, 201 first surface, 202 second surface, 203 third surface, 400 refrigeration cycle device, 401 compressor, 402 condenser, 40 3 Pressure reducing device, 404 Evaporator .

Claims

a stator core having an annular core back, teeth extending radially inward from the core back, and slots adjacent to the teeth in the circumferential direction of the core back;
an insulating section provided on the teeth;
and a winding wound around the teeth via the insulating part,
The teeth have an end face facing in the axial direction of the stator core, a side face facing the slot, and a stepped portion formed between the end face and the side face,
The insulating portion includes a first surface covering the end surface of the tooth, a second surface facing the slot, and a curved or inclined surface extending from the first surface to the second surface. has a certain third aspect,
In a cross section perpendicular to the extending direction of the teeth, a boundary between the first surface and the third surface is a point P, a boundary between the second surface and the third surface is a point Q, If U is the intersection of a first straight line passing through the point P and parallel to the axial direction and a second straight line passing through the point Q and perpendicular to the axial direction,
The height A of the stepped portion in the axial direction, the width B of the stepped portion in the direction orthogonal to the axial direction, the distance D1 from point P to intersection U, and the distance D2 from point Q to intersection U. but,
A stator that satisfies D1≦A and D2≦B.
The stator according to claim 1, wherein the height A and the width B of the stepped portion satisfy A>B.
With respect to the axial length L1 of the teeth, the height A of the stepped portion is
A/L1≦0.157
The stator according to claim 2, which satisfies the following.
The stator core faces the rotor core,
The stator core has a first region with a height A at one end in the axial direction, and a second region with a height A at the other end in the axial direction,
The length of the range of the first region facing the rotor core is shorter than the length of the range of the second region facing the rotor core,
The stator according to any one of claims 1 to 3, wherein the stepped portion is provided only in the first region of the stator core.
The stator core faces the rotor core,
The rotor core protrudes from the stator core by a distance Z1 from one end in the axial direction, and protrudes by a distance Z2 from the other end of the stator core in the axial direction,
Distance Z1 is shorter than distance Z2,
The stator according to any one of claims 1 to 4, wherein the step portion is provided only on the one end side of the stator core.
Claims 1 to 5, wherein the insulating part has a part that covers the end surface of the tooth, a part that covers the side surface of the tooth, and a part that covers the stepped part of the tooth, which are integrally formed. The stator according to any one of the items.
The stator according to any one of claims 1 to 6, wherein the insulating section includes an insulating film that covers the side surfaces of the teeth.
The core back has a stepped portion facing the slot at the end in the axial direction,
The tooth has a tooth tip portion at the tip in the radial direction,
The tooth tip has a stepped portion facing the slot at the end in the axial direction,
The stepped portion of the core back has a width E1,
The stepped portion of the tooth tip has a width E2,
The stator according to any one of claims 1 to 7, wherein the width E1 and the width E2 satisfy E1≦B and E2≦B.
The stator according to any one of claims 1 to 8, wherein the winding is made of aluminum wire.
A stator according to any one of claims 1 to 9,
and a rotor disposed inside the stator.
The electric motor according to claim 10;
A compressor comprising: a compression mechanism driven by the electric motor.
A refrigeration cycle device comprising the compressor according to claim 11, a condenser, a pressure reducing device, and an evaporator.