Electric motor, compressor and refrigeration cycle device

Abstract

In the present invention, an electric motor comprises: a rotor having an annular rotor core that is centered around an axis and is composed of electromagnetic steel sheet laminated in the direction of the axis, and a permanent magnet that is mounted to the rotor core; and a stator having a stator core that surrounds the rotor core and is composed of electromagnetic steel sheet laminated in the direction of the axis, and windings that are wound around the stator core and are composed of aluminum wire. The space factor O1 of the electromagnetic steel sheet of the stator core and the space factor O2 of the electromagnetic steel sheet of the rotor core are such that O1<O2.

Description

[Technical field]

[0001] The present disclosure relates to an electric motor, a compressor, and a refrigeration cycle device. [Background technology]

[0002] An electric motor has a rotor with a permanent magnet and a stator with windings. Copper wire is generally used for the windings, but lower-cost aluminum wire is increasingly being used (for example, Patent Document 1). [Prior art documents] [Patent documents]

[0003] [Patent Document 1] International Publication WO2017 / 126053 (see, for example, paragraphs 0017-0019) Summary of the Invention [Problem to be solved by the invention]

[0004] However, because aluminum wire has a higher electrical resistance than copper wire, the amount of heat generated increases when aluminum wire is used for the windings. If the temperature of the windings rises due to the increased amount of heat generated, the insulation coating of the windings may be damaged. Therefore, it is desirable to suppress the temperature rise of the windings.

[0005] The present disclosure has been made to solve the above-mentioned problems, and aims to suppress temperature rise when aluminum wire is used for the windings. [Means for solving the problem]

[0006] The electric motor according to the present disclosure is used in a compressor. The electric motor has an annular rotor core centered on an axis line, and is laminated in the axial direction. and fixed by caulking. The rotor has a rotor core made of magnetic steel sheets and a permanent magnet attached to the rotor core, and a stator core is fixed inside the compressor shell and surrounds the rotor core, and is laminated in the axial direction. and fixed by caulking. A stator includes a stator core composed of electromagnetic steel plates, and a winding wound around the stator core and composed of aluminum wires. The stator core has a recess on its outer periphery that forms a passage for a refrigerant between the inner peripheral surface of the shell. The refrigerant flowing through the recess passes through the winding through the gaps between the electromagnetic steel plates of the stator core. The crimping depth of the electromagnetic steel sheets of the stator core is deeper than the crimping depth of the electromagnetic steel sheets of the rotor core, and a gap L1 between the electromagnetic steel sheets of the stator core and a gap L2 between the electromagnetic steel sheets of the rotor core satisfy L1>L2. The stacking occupancy ratio O1 of the electromagnetic steel plates of the stator core and the stacking occupancy ratio O2 of the electromagnetic steel plates of the rotor core satisfy O1 < O2.

Advantages of the Invention

[0007] According to the above configuration, since the stacking occupancy ratio O1 of the electromagnetic steel plates of the stator core and the stacking occupancy ratio O2 of the electromagnetic steel plates of the rotor core satisfy O1 < O2, the amount of refrigerant passing through the gaps between the electromagnetic steel plates of the stator core can be made larger than the amount of refrigerant passing through the gaps between the electromagnetic steel plates of the rotor core. Therefore, the heat of the winding can be dissipated by the refrigerant passing through the gaps between the electromagnetic steel plates of the stator core, and the temperature rise of the winding can be suppressed.

Brief Description of the Drawings

[0008] [Figure 1] It is a cross-sectional view showing the electric motor of Embodiment 1. [Diagram 2] It is a cross-sectional view showing the stator core of Embodiment 1. [Diagram 3] It is a cross-sectional view showing the split core of Embodiment 1. [Figure 4] It is a cross-sectional view showing a part of the rotor of Embodiment 1. [Diagram 5] It is a longitudinal sectional view showing the electric motor of Embodiment 1. [Figure 6] It is a schematic diagram showing the electromagnetic steel plates of the stator core and the rotor core of Embodiment 1. [Figure 7] It is diagrams (A) and (B) showing a configuration example of the stator core of Embodiment 1. [Figure 8] It is a schematic diagram for explaining the winding method of the winding of Embodiment 1. [Figure 9]FIG. 2 is a schematic diagram showing a winding pattern of the winding according to the first embodiment. [Figure 10] 3 is a schematic diagram showing a contact portion between a stator core and a winding in the stator of the first embodiment. FIG. [Figure 11] 5 is a schematic diagram showing a contact portion between a stator core and a winding in a stator of a comparative example. FIG. [Figure 12] 11 is a schematic diagram showing electromagnetic steel sheets of a stator core and a rotor core in embodiment 2. FIG. [Figure 13] 13A and 13B are schematic diagrams illustrating a method for adjusting the gap between electromagnetic steel sheets in embodiment 2. [Figure 14] 13A and 13B are schematic diagrams illustrating a method for adjusting the gap between electromagnetic steel sheets in embodiment 2. [Figure 15] 11 is a schematic diagram showing a contact portion between a stator core and a winding in a stator according to a second embodiment. FIG. [Figure 16] 11 is a schematic diagram showing electromagnetic steel sheets of a stator core and a rotor core in embodiment 3. FIG. [Figure 17] 13A and 13B are a perspective view and a plan view showing a method for measuring iron loss of an electromagnetic steel sheet in embodiment 3. [Figure 18] FIG. 2 is a vertical sectional view showing a compressor to which the electric motor of each embodiment can be applied. [Figure 19] FIG. 19 is a diagram showing a refrigeration cycle device including the compressor shown in FIG. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0009] Embodiment 1 <Motor configuration> First, an electric motor 100 according to a first embodiment will be described. Fig. 1 is a cross-sectional view showing the 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 a compressor. The compressor will be described later with reference to Fig. 18.

[0010] The electric motor 100 includes a rotor 5 having a shaft 4 which is a rotating shaft, and a stator 1 provided 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 incorporated inside a cylindrical shell 8 of the compressor.

[0011] In the following, the direction of the axis Ax, which is the central axis of rotation of the rotor 5, is referred to as the "axial direction." The radial direction centered on the axis Ax is referred to as the "radial direction." The circumferential direction centered on the axis Ax is referred to as the "circumferential direction." A cross-sectional view taken on a plane parallel to the axis Ax is referred to as a longitudinal cross-sectional view, and a cross-sectional view taken on a plane perpendicular to the axis Ax is referred to as a transverse cross-sectional view.

[0012] <Stator configuration> Stator 1 has a stator core 10 and a winding 2 wound around stator core 10. Fig. 2 is a cross-sectional view showing stator core 10. Stator core 10 is formed by stacking electromagnetic steel sheets 101 (Fig. 5) in the axial direction and fixing them by crimping portions 17, 18 (Fig. 3). The front and back surfaces of electromagnetic steel sheets 101 are coated with an insulating film (not shown). Electromagnetic steel sheets 101 have a thickness of 0.1 to 0.7 mm, which will be described later.

[0013] The stator core 10 has an annular yoke 11 and a plurality of teeth 12 extending radially inward from the yoke 11. The teeth 12 are formed at equal intervals in the circumferential direction. The number of the teeth 12 is nine here, but is not limited to nine.

[0014] Each tooth 12 has a tooth tip 12a on its radially inner side, which has a circumferential width wider than the other portions. The tooth tip 12a faces the outer periphery of the rotor 5 (FIG. 1). The portion of each tooth 12 between the tooth tip 12a and the yoke 11 is called an extension 12b, and has a constant circumferential width. A slot 13 is formed between each pair of teeth 12 adjacent to each other in the circumferential direction. The slot 13 is an area that accommodates the winding 2 wound around the teeth 12.

[0015] The stator core 10 is formed by connecting a number of split cores 9 in an annular shape. Each split core 9 is a block including one tooth 12. The split cores 9 are divided by dividing surfaces 15 formed on the yoke 11. The number of split cores 9 is the same as the number of teeth 12, which is nine in this example.

[0016] It should be noted that stator core 10 is not limited to being formed by connecting split cores 9 in an annular shape, but may be formed by laminating electromagnetic steel plates punched into an annular shape.

[0017] 3 is a diagram showing one split core 9 of stator core 10. In split core 9, a recess 19 is formed on the outer periphery 11a of yoke 11. Recess 19 defines a coolant passage between stator core 10 and shell 8 (FIG. 1). Here, recess 19 is disposed on radial line E passing through the widthwise center of tooth 12, but is not limited to this position.

[0018] A through hole 16 is formed in the yoke 11. The through hole 16 is formed from one end to the other end in the axial direction of the stator core 10, and allows a refrigerant for the compressor to pass through. The through hole 16 is disposed radially inside the recess 19 on a radial line E passing through the widthwise center of the tooth 12, but is not limited to this position. The cross-sectional shape of the through hole 16 is semicircular here, and a chord portion faces the recess 19. However, the cross-sectional shape of the through hole 16 is not limited to a semicircular shape.

[0019] The yoke 11 is formed with a crimped portion 17 and a crimped portion 18 that fix the electromagnetic steel sheets 101 to each other. The crimped portion 17 is disposed radially inside the through hole 16, and the crimped portion 18 is disposed on both circumferential sides of the through hole 16. However, the arrangement of the crimped portions 17 and 18 is not limited to these positions. The crimped portion 17 is a round crimp and the crimped portion 18 is a V-shaped crimp, but is not limited to these.

[0020] As shown in Fig. 1, the windings 2 are made of magnet wire and are wound in a concentrated manner around each tooth 12. The magnet wire is made of aluminum wire, which is an aluminum conductor covered with an insulating coating.

[0021] The wire diameter of the magnet wire (here, aluminum wire) constituting the winding 2 is, for example, 1.0 mm. The number of turns of the winding 2 around one tooth 12 is, for example, 80 turns. The wire diameter and number of turns of the winding 2 are set according to the required characteristics of the electric motor 100 (for example, rotation speed and torque), the supply voltage, and the cross-sectional area of ​​the slot 13.

[0022] An insulating portion 3 is provided to insulate the stator core 10 from the windings 2. The insulating portion 3 has insulators 31 provided at both axial ends of the stator core 10 and insulating films 32 provided on the inner surfaces of the slots 13.

[0023] The insulator 31 is made of a resin such as PBT (polybutylene terephthalate). The insulating film 32 is made of a resin such as PET (polyethylene terephthalate) and has a thickness of 0.1 to 0.8 mm. The winding 2 is wound around the tooth 12 with the insulator 21 and the insulating film 32 interposed therebetween.

[0024] <Configuration of rotor 5> The rotor 5 has an annular rotor core 50 centered on the axis Ax, and permanent magnets 55 attached to the rotor core 50. The rotor core 50 is formed by stacking electromagnetic steel sheets 501 (FIG. 5) in the axial direction and fixing them by crimping portions 58 (FIG. 4). The front and back surfaces of the electromagnetic steel sheets 501 are coated with an insulating film (not shown). The thickness of the electromagnetic steel sheets 501 is 0.1 to 0.7 mm, which will be described later.

[0025] A central hole 54 is formed in the radial center of rotor core 50. Shaft 4 is fixed in central hole 54 of rotor core 50 by shrink fitting, press fitting, or the like. Rotor core 50 also has a circular outer periphery 50a.

[0026] A plurality of magnet insertion holes 51 are formed along the outer periphery 50a of the rotor core 50. One permanent magnet 55 is disposed in each magnet insertion hole 51. One magnet insertion hole 51 corresponds to one magnetic pole. Since the rotor core 50 has six magnet insertion holes 51, the rotor 5 has six poles.

[0027] The number of poles of the rotor 5 is not limited to six, but may be two or more. Furthermore, two or more permanent magnets 55 may be disposed in each magnet insertion hole 51. Each magnet insertion hole 51 may extend in a V-shape.

[0028] The permanent magnets 55 are flat members that are long in the axial direction of the rotor core 50, have a width in the circumferential direction, and a thickness in the radial direction. Each permanent magnet 55 is magnetized in the thickness direction. The permanent magnets 55 are made of a rare earth magnet containing, for example, neodymium (Nd), iron (Fe), and boron (B).

[0029] Rare earth magnets have the property that their coercivity decreases as the temperature rises, with the rate of decrease being -0.5 to -0.6 [% / K]. In order to prevent demagnetization of rare earth magnets when the maximum load assumed in the compressor occurs, a coercivity of 1100 to 1500 [A / m] is required. In order to ensure this coercivity at an ambient temperature of 150°C, the coercivity at room temperature, i.e., 20 [°C], needs to be 1800 to 2300 [A / m].

[0030] For this reason, dysprosium (Dy) may be added to rare earth magnets. The coercive force of a rare earth magnet at room temperature is 1800 [A / m] without the addition of Dy, and increases to 2300 [A / m] by adding 2 [wt%] of Dy. However, the addition of Dy increases manufacturing costs and reduces the residual magnetic flux density, so it is desirable to add as little Dy as possible, or to not add Dy at all.

[0031] 4 is an enlarged view of a portion of the rotor 5. The magnet insertion hole 51 extends linearly in a direction perpendicular to a radial line passing through the circumferential center of the magnet insertion hole 51. The circumferential center of the magnet insertion hole 51 is the pole center P. The radial line passing through the pole center P is called the pole center line. A pole gap M is formed between adjacent magnetic poles.

[0032] Flux barriers 52, which are voids, are formed on both circumferential sides of the magnet insertion holes 51. Bridge portions 53, which are thin portions, are formed between the flux barriers 52 and the outer periphery 50a of the rotor core 50. The bridge portions 53 have a radial width W, which will be described later.

[0033] A radially long slit 59 is formed on the radial outside of the magnet insertion hole 51. The slits 59 are formed to control the magnetic flux density distribution on the surface of the rotor 5. Here, seven slits 59 are formed symmetrically with respect to the pole center line, but the number and arrangement of the slits 59 are arbitrary. Also, the rotor core 50 does not necessarily have to be provided with the slits 59.

[0034] Through holes 56, 57 are formed radially inside the magnet insertion hole 51. The through holes 56, 57 are formed from one end to the other end in the axial direction of the rotor core 50 and form a refrigerant passage. The circumferential position of the through hole 56 coincides with the pole center P, and the circumferential position of the through hole 57 coincides with the pole gap M, but are not limited to these positions. Furthermore, the rotor core 50 does not necessarily have to be provided with the through holes 56, 57.

[0035] The crimped portions 58 that fix the electromagnetic steel sheets 501 are formed at circumferential positions corresponding to the inter-pole gap M, radially inward of the flux barriers 52. However, the arrangement of the crimped portions 58 is not limited to these positions. The crimped portions 58 are omitted in FIG. 1.

[0036] <Configuration for Suppressing Temperature Increase of Winding 2> FIG. 5 is a longitudinal sectional view showing the electric motor 100. Insulators 31 described above are provided at both axial ends of the stator core 10. The insulator 31 has an outer peripheral wall 31a, an inner peripheral wall 31c, and a body portion 31b.

[0037] The outer peripheral wall 31a of the insulator 31 is located on the yoke 11 (FIG. 3), the inner peripheral wall 31c is located on the tooth tip portion 12a (FIG. 3) of the teeth 12, and the body portion 31b is located on the extending portion 12b (FIG. 3) of the teeth 12. The winding 2 is wound around the body portion 31b and is guided from both radial sides by the outer peripheral wall 31a and the inner peripheral wall 31c.

[0038] Let the axial length of the stator core 10 be H1, and the axial length of the rotor core 50 be H2. Here, the length H1 of the stator core 10 is shorter than the length H2 of the rotor core 50. That is, H1 < H2 holds. However, the present invention is not limited to such a configuration, and the length H1 of the stator core 10 may be the same as or longer than the length H2 of the rotor core 50.

[0039] The outer periphery of the stator core 10, that is, the outer periphery 11a of the yoke 11, is fixed to the inner periphery of the shell 8 of the compressor. A refrigerant passage is formed by the concave portion 19 (FIG. 3) described above between the stator core 10 and the shell 8.

[0040] FIG. 6 is a schematic view showing the electromagnetic steel sheets 101 and 501 of the stator core 10 and the rotor core 50. The electromagnetic steel sheet 101 constituting the stator core 10 has a thickness T1, and the electromagnetic steel sheet 501 constituting the rotor core 50 has a thickness T2. In Embodiment 1, the thickness T1 of the electromagnetic steel sheet 101 is thinner than the thickness T2 of the electromagnetic steel sheet 501. That is, T1 < T2 holds.

[0041] As an example, the thickness T1 of the electromagnetic steel sheet 101 is 0.35 [mm], and the thickness T2 of the electromagnetic steel sheet 501 is 0.5 [mm].

[0042] The lamination gap L1 between the electromagnetic steel sheets 101 of the stator core 10 and the lamination gap L2 between the electromagnetic steel sheets 501 of the rotor core 50 are the same (i.e., L1=L2). The lamination gap L1 is the gap between the electromagnetic steel sheets 101 adjacent to each other in the axial direction. The lamination gap L2 is the gap between the electromagnetic steel sheets 501 adjacent to each other in the axial direction. Both lamination gaps L1 and L2 are on the order of 10 μm, i.e., 10 -2 The value is on the order of [mm].

[0043] In addition, when the gap between adjacent electromagnetic steel sheets 101 is not constant in a plane perpendicular to the axis Ax, the average value is taken as the lamination gap L1. Similarly, when the gap between adjacent electromagnetic steel sheets 501 is not constant in a plane perpendicular to the axis Ax, the average value is taken as the lamination gap L2.

[0044] In the first embodiment, the electromagnetic steel sheets 101 of the stator core 10 and the electromagnetic steel sheets 501 of the rotor core 50 are formed from the same material and therefore have the same silicon content. An example in which the silicon contents of the electromagnetic steel sheets 101, 501 are different will be described in the third embodiment.

[0045] The lamination space factor O1 of the stator core 10 is the space factor of the electromagnetic steel sheets 101 per unit length in the axial direction of the stator core 10. The lamination space factor O1 is calculated from the axial length H1 of the stator core 10, the thickness T1 of the electromagnetic steel sheets 101, and the number n1 of the sheets, as follows: O1= (T1×n1) / H1 This can be calculated by multiplying the percentage by 100.

[0046] For example, when the lamination space factor O1 of stator core 10 is 90[%], 10[%] of the axial length of stator core 10 is occupied by air gaps.

[0047] When calculating the lamination space factor O1, first the thickness T1 of one of the electromagnetic steel sheets 101 is measured, then n1 electromagnetic steel sheets 101 are stacked to form the stator core 10, after which the length H1 of the stator core 10 is measured, and the lamination space factor O1 is calculated using the above formula.

[0048] Further, let the occupation ratio of the electromagnetic steel sheets 501 per unit axial length of the rotor core 50 be the lamination occupation ratio O2 of the rotor core 50. The lamination occupation ratio O2 is obtained from the axial length H2 of the rotor core 50, the thickness T2 of the electromagnetic steel sheet 501, and the number of sheets n2 as O2 = (T2×n2) / H2 × 100 [%].

[0049] When obtaining the lamination occupation ratio O2, first measure the thickness T2 of one electromagnetic steel sheet 501, and then stack n2 electromagnetic steel sheets 501 to form the rotor core 50, and then measure the length H2 of the rotor core 50, and calculate the lamination occupation ratio O2 from the above formula.

[0050] The lamination occupation ratio O1 of the stator core 10 is smaller than the lamination occupation ratio O2 of the rotor core 50. In other words, O1 < O2 is satisfied. As an example, the lamination occupation ratio O1 is 95 [%], and the lamination occupation ratio O2 is 97 [%].

[0051] Since the lamination occupation ratio O1 of the stator core 10 is smaller than the lamination occupation ratio O2 of the rotor core 50, the total gap 102 between the electromagnetic steel sheets 101 of the stator core 10 per unit axial length is 502 more than the total gap

[0052] between the electromagnetic steel sheets 501 of the rotor core 50. As a result, as described later, the amount of refrigerant flowing inside the stator core 10 increases, and the effect of suppressing the temperature rise of the winding 2 is obtained.

[0053] <Manufacturing method of electric motor> Next, a manufacturing method of the electric motor 100 of the first embodiment will be described. First, an electromagnetic steel sheet 101 is punched by pressing into a shape in which the split cores 9 are linearly arranged as shown in Fig. 7(A). In the example shown in Fig. 7(A), the split cores 9 are connected to each other at connecting parts C on the outer periphery side of the dividing surface 15. However, the split cores 9 may be spaced apart from each other as shown in Fig. 7(B).

[0054] Thereafter, the punched electromagnetic steel sheets 101 are stacked in the axial direction and fixed at crimped portions 17, 18 to form a laminate. An insulating portion 3 is attached to this laminate, and a winding 2 is wound around each of the teeth 12.

[0055] There are two methods for winding the winding 2: concentrated winding and distributed winding, but concentrated winding is used here. In particular, the winding 2 is not wound across multiple teeth 12, but is wound around each tooth 12. This type of winding method is called salient pole concentrated winding.

[0056] Fig. 8 is a schematic diagram for explaining a method for winding the winding 2. Fig. 8 is a view of the insulator 31 as viewed from one side in the axial direction. In Fig. 8, the circumferential direction is indicated by arrow A. The winding 2 is wound around the teeth 12 by a winding nozzle via the insulator 31 and the insulating film 32 (Fig. 1).

[0057] The first layer of the winding 2 is wound from the inner circumferential wall 31c to the outer circumferential wall 31a of the insulator 31, as indicated by arrow B1. The second layer of the winding 2 is wound from the outer circumferential wall 31a to the inner circumferential wall 31c of the insulator 31, as indicated by arrow B2. The directions of the arrows B1 and B2 may be reversed.

[0058] Fig. 9 is a cross-sectional view taken along a plane perpendicular to the axis Ax, showing the winding pattern of the winding 2. In Fig. 9, the circumferential direction is indicated by arrow A, and the radial direction is indicated by arrow R. Additionally, the coils in the first, second, third, and fourth layers of the winding 2 are indicated by the symbols C1, C2, C3, and C4, respectively.

[0059] The winding 2 is wound in an aligned manner. That is, where n is an integer equal to or greater than 1, each coil Cn+1 in the (n+1)th layer is arranged so as to be in contact with two coils Cn in the nth layer. Since the winding 2 is wound in an aligned manner, the winding 2 and the teeth 12 are closely attached to each other.

[0060] On one axial end face of tooth 12, there is a cross point CP where coil Cn of the nth layer and coil Cn+1 of the n+1th layer of winding 2 intersect. Meanwhile, all of the coils of winding 2 located within slot 13 extend in the axial direction. This results in particularly strong adhesion between winding 2 and the side face of tooth 12, i.e., the face on the slot 13 side.

[0061] After winding the winding 2 around each tooth 12 in this manner, the split cores 9 are assembled into a ring shape. Concatenation 7(B), when the split cores 9 are spaced apart from each other, the split cores 9 are welded to each other at their dividing surfaces 15.

[0062] Through the above steps, the stator 1 in which the windings 2 are wound around the stator core 10 is completed.

[0063] The rotor 5 is assembled in parallel with the assembly of the stator 1. Specifically, electromagnetic steel sheets 501 are stacked in the axial direction and fixed at crimped portions 58 to form the rotor core 50. In addition, permanent magnets 55 are inserted into magnet insertion holes 51 of the rotor core 50. If necessary, a balance weight may be attached to the rotor core 50. In this manner, the rotor 5 is completed.

[0064] After that, the rotor 5 is assembled inside the stator 1. This completes the electric motor 100. Note that, although the windings 2 are wound around the teeth 12 of the split cores 9 and then the split cores 9 are assembled into an annular shape here, the windings 2 may also be wound around the teeth 12 of an annular stator core 10.

[0065] <effect> Next, a description will be given of the operation of embodiment 1. Fig. 10 is a schematic diagram showing a contact portion between stator core 10 and windings 2 in stator 1 of embodiment 1. Fig. 11 is a schematic diagram showing a contact portion between stator core 10 and windings 2 in stator 1C of a comparative example.

[0066] 10 and 11 are cross sections taken along a plane that crosses the slot 13 (FIG. 3) of the stator 1 in the radial direction. The radial inside, i.e., the tooth tip 12a side of the tooth 12, is indicated by arrow Ri, and the radial outside, i.e., the yoke 11 side, is indicated by arrow Ro. The direction of the axis Ax is also indicated by arrow Ax.

[0067] 10 and 11, gaps 102 are formed between axially adjacent electromagnetic steel sheets 101. In the compressor, the refrigerant flows through a refrigerant passage between recess 19 (FIG. 3) of stator core 10 and shell 8, and some of the refrigerant flows through gaps 102 in stator core 10 as indicated by arrow F.

[0068] The refrigerant that flows through gaps 102 in stator core 10 flows radially inward and passes through windings 2. This refrigerant acts to dissipate heat from windings 2. Note that although insulating film 32 is interposed between stator core 10 and windings 2, it is thin and therefore has little effect on the heat dissipation function from windings 2 by the refrigerant.

[0069] 11 is thicker than thickness T1 of electromagnetic steel sheets 101 of stator core 10 of embodiment 1. Therefore, in embodiment 1, the number of gaps 102 per unit length in the axial direction of stator core 10 is greater than that in the comparative example. That is, lamination space factor O1 of electromagnetic steel sheets 101 of stator core 10 of embodiment 1 is smaller than lamination space factor Oc of electromagnetic steel sheets 101 of stator core 10 of the comparative example.

[0070] The smaller the lamination space factor, the larger the total number of gaps 102 per unit length in the axial direction, and therefore the larger the flow rate of the coolant flowing through the gaps 102. In the first embodiment, the thickness T1 of the electromagnetic steel sheets 101 is thin, and therefore the lamination space factor O1 is small, so the amount of coolant flowing through the gaps 102 of the stator core 10 is greater than in the comparative example.

[0071] Winding 2 is made of aluminum wire, which has a higher electrical resistance than copper wire, and therefore generates a large amount of heat when current is applied. In the first embodiment, the refrigerant can efficiently dissipate heat from winding 2, thereby suppressing a rise in temperature of winding 2.

[0072] Furthermore, through holes 16 (FIG. 3) are formed in stator core 10, and the coolant flows into gaps 102 from through holes 16. This increases the amount of coolant flowing through gaps 102, thereby enhancing the effect of suppressing the temperature rise of windings 2.

[0073] The number and arrangement of through holes 16 in stator core 10 is arbitrary. However, because through holes 16 impede the magnetic flux flowing through stator core 10, it is preferable to form them in yoke 11 rather than in teeth 12 where magnetic flux flows in a concentrated manner.

[0074] In particular, as shown in FIG. 3, if the through hole 16 is arranged on a radial straight line E passing through the circumferential center of the tooth 12 in the yoke 11, it is possible to ensure the refrigerant flow rate while minimizing the obstruction of the magnetic flux.

[0075] In addition, in FIG. 1, insulator 31 is positioned in a position that blocks through hole 16 of stator core 10. However, if insulator 31 is positioned in a position that does not block through hole 16, as shown by the dashed line in FIG. 3 (i.e., if through hole 16 is exposed), the refrigerant will be able to flow more easily into through hole 16, thereby further enhancing the effect of suppressing the temperature rise of winding 2.

[0076] However, even if through hole 16 is blocked by insulator 31 (FIG. 1), the coolant flows from recess 19 through gap 102 into through hole 16, so the effect of suppressing the temperature rise of winding 2 due to the coolant can be obtained.

[0077] Generally, the thinner the electromagnetic steel sheet, the smaller the iron loss generated in the electromagnetic steel sheet. In the first embodiment, thickness T1 of electromagnetic steel sheet 101 of stator core 10 is thinner than thickness T2 of electromagnetic steel sheet 501 of rotor core 50, so that iron loss in stator core 10 can be reduced and temperature rise in stator core 10 can be suppressed.

[0078] Since the temperature rise of stator core 10 is suppressed, the coolant is less likely to be heated when passing through gaps 102 of stator core 10. This enhances the heat dissipation effect of windings 2 by the coolant, thereby enhancing the effect of suppressing the temperature rise of windings 2.

[0079] Comparing stator core 10 and rotor core 50, the iron loss generated in stator core 10 is greater than the iron loss generated in rotor core 50. This is because the relative position of stator core 10 with respect to the magnetic flux of permanent magnet 55 changes significantly when rotor 5 rotates.

[0080] It is generally known that the iron loss generated in stator core 10 is two to four times the iron loss generated in rotor core 50. It is also known that the iron loss is inversely proportional to the first to second powers of the thickness of the electromagnetic steel sheet. Therefore, if thickness T2 of electromagnetic steel sheet 501 of rotor core 50 is set to √2 to 4 times thickness T1 of electromagnetic steel sheet 101 of stator core 10, equivalent iron loss will be generated in stator core 10 and rotor core 50.

[0081] The lower limit value, √2, is the value when the iron loss generated in stator core 10 is twice the iron loss generated in rotor core 50, and the iron loss is inversely proportional to the square of the thickness of the electromagnetic steel sheets. The upper limit value, 4, is the value when the iron loss generated in stator core 10 is four times the iron loss generated in rotor core 50, and the iron loss is inversely proportional to the square of the thickness of the electromagnetic steel sheets.

[0082] On the other hand, if the thickness T2 of the electromagnetic steel sheet 501 of the rotor core 50 exceeds four times the thickness T1 of the electromagnetic steel sheet 101 of the stator core 10, the iron loss generated in the rotor core 50 may exceed the iron loss generated in the stator core 10. As a result, the heat of the rotor core 50 may transfer to the stator core 10, and the effect of suppressing the temperature rise of the winding 2 may decrease. Therefore, it is desirable that the thicknesses T1 and T2 satisfy T2 < 4 × T1.

[0083] Also, as shown in FIG. 4, it is more desirable that the radial width W of the bridge portion 53 between the flux barrier 52 and the outer periphery 50a of the rotor core 50 is equal to or less than the thickness T1 of the electromagnetic steel sheet 101 of the stator core 10. That is, it is desirable that W < T1 holds. This will be described below.

[0084] When the motor 100 is driven, a current having a frequency synchronized with the rotational speed is supplied to the winding 2 of the stator 1, thereby generating a rotating magnetic field and causing the rotor 5 to rotate. At this time, a part of the magnetic flux flowing from the teeth 12 to the rotor core 50 passes through the bridge portion 53 of the rotor core 50 and returns to the adjacent teeth 12. That is, a short-circuit path passing through the bridge portion 53 is formed.

[0085] The magnetic flux flowing through the short-circuit path does not contribute to the rotation of the rotor 5 and may cause iron loss at the tooth tip portion 12a of the teeth 12. When iron loss occurs at the tooth tip portion 12a, the temperature of the stator core 10 may rise, and the effect of suppressing the temperature rise of the winding 2 may decrease. Therefore, it is desirable to reduce the magnetic flux flowing through the short-circuit path.

[0086] The range of the magnetic flux flowing axially within the bridge portion 53 is restricted by the thickness T1 of the electromagnetic steel sheet 101 of the stator core 10. This is because an insulating film is coated on the front and back surfaces of the electromagnetic steel sheets 101 and 501, and the magnetic flux flowing axially through one electromagnetic steel sheet 501 flows not through the axially adjacent electromagnetic steel sheet 501 but through the electromagnetic steel sheet 101 of the stator core 10.

[0087] On the other hand, the magnetic flux flowing radially within the bridge portion 53 is restricted by the radial width W of the bridge portion 53. By making the radial width W of the bridge portion 53 narrower than the above-described thickness T1, the flow of the radial magnetic flux can be suppressed. As a result of suppressing the magnetic flux from the stator core 10 toward the rotor core 50, the magnetic flux flowing through the short-circuit path can be suppressed, and a decrease in the effect of suppressing the temperature rise of the winding 2 can be suppressed.

[0088] <Effects of the Embodiment> As described above, in the electric motor 100 of Embodiment 1, a rotor 5 having a rotor core 50 and a permanent magnet 55, and a stator 1 having a stator core 10 and a winding 2 are provided, and the stacking occupation ratio O1 of the electromagnetic steel sheets 101 of the stator core 10 and the stacking occupation ratio O2 of the electromagnetic steel sheets 501 of the rotor core 50 satisfy O1 < O2. Therefore, by increasing the amount of refrigerant flowing through the gaps 102 between the electromagnetic steel sheets 101 of the stator core 10 and depriving the winding 2 of heat with the refrigerant, the temperature rise of the winding 2 can be suppressed.

[0089] Also, since the thickness T1 of the electromagnetic steel sheet 101 of the stator core 10 is thinner than the thickness T2 of the electromagnetic steel sheet 501 of the rotor core 50, the number of gaps 102 of the stator core 10 per unit length in the axial direction increases, and thereby the amount of refrigerant passing through the gaps 102 can be increased. Further, by making the thickness T1 thinner, the generation of iron loss in the stator core 10 can be suppressed, and the temperature rise of the stator core 10 can be suppressed. As a result, the effect of suppressing the temperature rise of the winding 2 can be enhanced.

[0090] Also, since the thickness T1 and the thickness T2 satisfy T2 < 4 × T1, the temperature rise due to the iron loss generated in the rotor core 50 can be suppressed, and the temperature rise of the winding 2 due to the heat transfer from the rotor core 50 to the stator core 10 can be suppressed.

[0091] In addition, because the radial width W of bridge portions 53 of rotor core 50 is thinner than the thickness T1 of electromagnetic steel sheets 101 of stator core 10, it is possible to suppress the magnetic flux flowing between teeth 12 via a short-circuit path. This makes it possible to suppress the occurrence of iron loss at tooth tips 12a and to enhance the effect of suppressing the temperature rise of windings 2.

[0092] In addition, since the stator core 10 has a through hole 16 formed from one end to the other end in the axial direction of the stator core 10, the refrigerant in the compressor can easily flow into the gap 102 via the through hole 16, thereby enhancing the effect of suppressing the temperature rise of the winding 2.

[0093] Furthermore, since the stator core 10 has a recess 19 that forms a refrigerant passage between the stator core 10 and the inner surface of the compressor shell 8, the refrigerant inside the compressor can easily flow into the gap 102 via the recess 19, thereby enhancing the effect of suppressing the temperature rise of the winding 2.

[0094] In addition, because the winding 2 is wound around the teeth 12 in a salient-pole concentrated winding manner, it is possible to increase the degree of contact between the winding 2 and the teeth 12. As a result, the refrigerant that passes through the gaps 102 comes into contact with the winding 2 more frequently, thereby improving the effect of suppressing the temperature rise of the winding 2.

[0095] In addition, because the stator core 10 is composed of multiple split cores 9, the windings 2 can be wound around the teeth 12 before the split cores 9 are combined into an annular shape. This allows the winding nozzle greater freedom of movement, allowing the windings 2 to be wound at a high density. This increases the degree of contact between the windings 2 and the teeth 12, and improves the effect of suppressing temperature rise of the windings 2.

[0096] Embodiment 2 Next, a second embodiment will be described. Fig. 12 is a schematic diagram showing a stator core 10A of a stator 1A and a rotor core 50A of a rotor 5A in the second embodiment. In the second embodiment, lamination gap L1 of electromagnetic steel sheets 101 of stator core 10A is larger than lamination gap L2 of electromagnetic steel sheets 501 of rotor core 50A. That is, L1>L2 holds.

[0097] The thickness T1 of the electromagnetic steel sheet 101 of the stator core 10A is the same as the thickness T2 of the electromagnetic steel sheet 501 of the rotor core 50A. That is, T1 = T2 holds. However, the thickness T1 of the electromagnetic steel sheet 101 of the stator core 10A may be thinner than the thickness T2 of the electromagnetic steel sheet 501 of the rotor core 50A as in the first embodiment.

[0098] Also in this second embodiment, the stacking occupation ratio O1 of the electromagnetic steel sheet 101 of the stator core 10A is smaller than the stacking occupation ratio O2 of the electromagnetic steel sheet 501 of the rotor core 50A. That is, O1 < O2 holds.

[0099] The stacking gap L1 of the electromagnetic steel sheet 101 can be adjusted when caulking portions 17, 18 (FIG. 3) are formed. The caulking portions 17, 18 are both formed by pressing the electromagnetic steel sheet 101.

[0100] FIGS. 13(A) and (B) are a plan view and a cross-sectional view schematically showing the caulking portion 18 which is a V-caulking. By fitting the V-shaped convex portion 18a formed on the back surface of the electromagnetic steel sheet 101 into the V-shaped concave portion 18b formed on the surface of the lower electromagnetic steel sheet 101, a plurality of electromagnetic steel sheets 101 are fixed to each other. By adjusting the protruding amount of the convex portion 18a, that is, the depth of the concave portion 18b (referred to as the caulking depth D) during pressing, the stacking gap L1 of the electromagnetic steel sheet 101 can be adjusted.

[0101] FIGS. 14(A) and (B) are a plan view and a cross-sectional view schematically showing the caulking portion 17 which is a round caulking. By fitting the cylindrical convex portion 17a formed on the back surface of the electromagnetic steel sheet 101 into the cylindrical concave portion 17b formed on the surface of the lower electromagnetic steel sheet 101, a plurality of electromagnetic steel sheets 101 are fixed to each other. By adjusting the protruding amount of the convex portion 17a, that is, the depth of the concave portion 17b (referred to as the caulking depth) D during pressing, the stacking gap L1 of the electromagnetic steel sheet 101 can be adjusted.

[0102] 13(A) to 14(B) show crimped portions 17, 18 of electromagnetic steel sheets 101 of stator core 10A, but lamination gap L2 of electromagnetic steel sheets 501 of rotor core 50A can also be adjusted in a similar manner.

[0103] In embodiment 2, by making the crimping depth D of the electromagnetic steel sheets 101 of the stator core 10A deeper than the crimping depth D of the electromagnetic steel sheets 501 of the rotor core 50A, a configuration is realized in which the lamination gap L1 of the electromagnetic steel sheets 101 is wider than the lamination gap L2 of the electromagnetic steel sheets 501.

[0104] FIG. 15 shows a stator 1 according to the second embodiment. A 15 is a schematic diagram showing a contact portion between a stator core 10A and a winding 2 in a stator core 10A shown in FIG. 15. Fig. 15 is a cross section cut along a plane that crosses a slot 13 in the radial direction. The radial inside, i.e., the tooth tip 12a side, is indicated by an arrow Ri, and the radial outside, i.e., the yoke 11 side, is indicated by an arrow Ro. The direction of the axis Ax is also indicated by an arrow Ax.

[0105] As described above, the embodiment 2 The lamination gap L1 between the electromagnetic steel sheets 101 of the stator core 10A is 1 The lamination gap L2 (Fig. 1 2 ) As a result, the amount of coolant flowing through gaps 102 in stator core 10A can be increased, thereby improving the efficiency with which the temperature rise in windings 2 is suppressed.

[0106] Except for the above points, the electric motor of the second embodiment is configured similarly to the electric motor 100 of the first embodiment.

[0107] As described above, according to embodiment 2, since the lamination gap L1 of stator core 10A is wider than the lamination gap L2 of rotor core 50A, the amount of refrigerant passing through gap 102 of stator core 10A can be increased, thereby suppressing the temperature rise of winding 2.

[0108] Between the thickness T1 and the lamination gap L1 of the electromagnetic steel sheet 101 of the stator core 10A and the thickness T2 and the lamination gap L2 of the electromagnetic steel sheet 501 of the rotor core 50A, in the first embodiment, T1 < T2 and L1 = L2 were satisfied, and in the second embodiment, T1 = T2 and L1 > L2 were satisfied. However, these examples are not limited thereto, and both T1 < T2 and L1 > L2 may be satisfied.

[0109] Embodiment 3. Next, Embodiment 3 will be described. FIG. 16 is a schematic diagram showing the stator core 10B of the stator 1B and the rotor core 50B of the rotor 5B in Embodiment 3. In Embodiment 3, the iron loss density of the electromagnetic steel sheet 101 of the stator core 10B by the Epstein test is higher than that of the electromagnetic steel sheet 501 of the rotor core 50B.

[0110] In FIG. 16, similar to the first embodiment, the thickness T1 of the electromagnetic steel sheet 101 of the stator core 10B is thinner than the thickness T2 of the electromagnetic steel sheet 501 of the rotor core 50B. However, as described in the second embodiment, the lamination gap L1 of the stator core 10B may be wider than the lamination gap L2 of the rotor core 50B, or a combination thereof may be used.

[0111] The Epstein test is defined in JIS_C2550. FIGS. 17(A) and (B) are schematic diagrams for explaining the Epstein test. As shown in FIG. 17(A), in the Epstein test, a sample 7 obtained by processing an electromagnetic steel sheet into a strip shape is used. The width of the sample 7 is 30 mm, and the length is 280 mm.

[0112] As shown in FIG. 17(B), the Epstein tester has a winding frame 65 formed of an insulating resin. The winding frame 65 is a combination of four winding frame portions 66, 67, 68, and 69 in a square shape. The winding frame portions 66 to 69 all have a rectangular cross section and have a space inside.

[0113] Inside the winding frames 66 to 69, the sample 7 of the above-mentioned number is inserted in a grid-like manner, and a magnetic path 70 is formed. Coils 6 are respectively wound around the outer circumferences of the winding frames 66 to 69. The coil 6 has a primary coil 61 on the input side and a secondary coil 62 on the detection side. The primary coil 61 and the secondary coil 62 have the same number of turns.

[0114] Based on the difference between the product of the primary current and the primary voltage input to the primary coil 61 and the product of the secondary current and the secondary voltage input to the secondary coil 62, the iron loss of the sample 7 is measured. The iron loss per unit weight when a sinusoidal magnetic flux density change with a maximum magnetic flux density of 1.5 T at a frequency of 50 Hz is induced is referred to as the iron loss density [W / kg].

[0115] In Embodiment 3, the iron loss density W1 of the electromagnetic steel sheet 101 of the stator core 10B is lower than the iron loss density W2 of the electromagnetic steel sheet 501 of the rotor core 50B. That is, W1 < W2 holds. As an example, the iron loss density W1 of the electromagnetic steel sheet 101 of the stator core 10B is 2.0 to 2.5 [W / kg], and the iron loss density W2 of the electromagnetic steel sheet 501 of the rotor core 50B is 2.5 to 5.0 [W / kg].

[0116] By making the iron loss density W1 of the electromagnetic steel sheet 101 of the stator core 10B lower than the iron loss density W2 of the electromagnetic steel sheet 501 of the rotor core 50B, the iron loss generated in the stator core 10B can be reduced, and the temperature rise can be suppressed. As a result, the temperature rise of the refrigerant passing through the air gap 102 of the stator core 10B is less likely to occur. As a result, the heat dissipation effect of the refrigerant on the winding 2 can be enhanced, and the effect of suppressing the temperature rise of the winding 2 can be enhanced.

[0117] Such a difference in the iron loss density W1, W2 can be realized, for example, by making the silicon content S1 of the electromagnetic steel sheet 101 larger than the silicon content S2 of the electromagnetic steel sheet 501 (that is, S1 > S2).

[0118] As an example, the silicon content S1 of the electromagnetic steel sheets 101 of the stator core 10B is 3.5 [weight %], and the silicon content S2 of the electromagnetic steel sheets 501 of the rotor core 50B is 3.3 [weight %]. [weight % ] It is desirable that the range is within the range.

[0119] The silicon contents S1, S2 of the electromagnetic steel sheets 101, 501, respectively, can be adjusted by selecting the grade or model number of the electromagnetic steel sheets 101, 501, etc.

[0120] In general, the higher the silicon content of an electromagnetic steel sheet, the lower the iron loss density in the Epstein test, and the lower the iron loss generated in the electromagnetic steel sheet. Therefore, by making the silicon content S1 of the electromagnetic steel sheet 101 of the stator core 10B higher than the silicon content S2 of the electromagnetic steel sheet 501 of the rotor core 50B, the iron loss generated in the stator core 10B can be reduced and the temperature rise can be suppressed. This makes it difficult for the temperature rise of the refrigerant passing through the gap 102 of the stator core 10B to occur, thereby strengthening the heat dissipation effect of the refrigerant from the winding 2 and enhancing the effect of suppressing the temperature rise of the winding 2.

[0121] As described above, according to the third embodiment, the iron loss density W1 of electromagnetic steel sheets 101 of stator core 10B determined by the Epstein test is lower than the iron loss density W2 of electromagnetic steel sheets 501 of rotor core 50B determined by the Epstein test. Therefore, the iron loss generated in stator core 10B can be reduced and a temperature rise can be suppressed, thereby enhancing the effect of suppressing the temperature rise of winding 2 caused by the refrigerant passing through gaps 102 in stator core 10B.

[0122] Furthermore, since the silicon content S1 of the electromagnetic steel sheets 101 of the stator core 10B is greater than the silicon content S2 of the electromagnetic steel sheets 501 of the rotor core 50B, the iron loss generated in the stator core 10B can be reduced and the temperature rise can be suppressed, thereby enhancing the effect of suppressing the temperature rise of the windings 2 due to the refrigerant passing through the gaps 102 of the stator core 10B.

[0123] <Compressor> 18 is a vertical cross-sectional view showing a compressor 300 to which the electric motor of each embodiment can be applied. The compressor 300 is a rotary compressor, and is used in, for example, a refrigeration cycle device 400 (FIG. 19).

[0124] 18 is a cross-sectional view showing a compressor 300. The compressor 300 is a rotary compressor in this case, and includes a sealed container 307, a compression mechanism 301 disposed in the sealed container 307, and an electric motor 100 that drives the compression mechanism 301.

[0125] Compression mechanism 301 has a cylinder 302 having a cylinder chamber 303, a shaft 4 of electric motor 100, a rolling piston 304 fixed to the shaft 4, a vane (not shown) that divides the inside of cylinder chamber 303 into a suction side and a compression side, and an upper frame 305 and a lower frame 306 into which shaft 4 is inserted and which close the axial end faces of cylinder chamber 303. An upper discharge muffler 308 and a lower discharge muffler 309 are attached to upper frame 305 and lower frame 306, respectively.

[0126] Sealed container 307 is a cylindrical container and includes shell 8 shown in Fig. 1. Refrigeration oil (not shown) for lubricating each sliding part of compression mechanism 301 is stored in the bottom of sealed container 307. Shaft 4 is rotatably supported by upper frame 305 and lower frame 306 serving as bearings.

[0127] The cylinder 302 has a cylinder chamber 303 therein, and the rolling piston 304 rotates eccentrically within the cylinder chamber 303. The shaft 4 has an eccentric shaft portion, and the rolling piston 304 is fitted into the eccentric shaft portion.

[0128] The stator 1 of the electric motor 100 is assembled inside the shell 8 of the sealed container 307 by a method such as shrink fitting, press fitting, or welding. Electricity is supplied to the windings 2 of the stator 1 from a glass terminal 311 fixed to the sealed container 307. The shaft 4 is fixed to the central hole 54 of the rotor 5.

[0129] An accumulator 310 is attached to the outside of the sealed container 307. Refrigerant gas flows into the accumulator 310 from the refrigerant circuit via a suction pipe 314. When liquid refrigerant flows in together with the refrigerant gas from the suction pipe 314, the liquid refrigerant is stored in the accumulator 310, and the refrigerant gas is supplied to the compressor 300.

[0130] A suction pipe 313 is fixed to the sealed container 307, and refrigerant gas is supplied from the accumulator 310 to the cylinder 302 via this suction pipe 313. In addition, a discharge pipe 312 that discharges the refrigerant to the outside is provided at the top of the sealed container 307.

[0131] The refrigerant for the compressor 300 may be, for example, R410A, R407C, or R22, but from the viewpoint of preventing global warming, it is preferable to use a refrigerant with a low GWP (global warming potential). For example, the following refrigerants can be used as refrigerants with a low GWP.

[0132] (1) First, halogenated hydrocarbons having carbon double bonds in their composition, such as HFO (Hydro-Fluoro-Orefin)-1234yf (CF3CF=CH2), can be used. The GWP of HFO-1234yf is 4. (2) Hydrocarbons having carbon double bonds in their composition, such as R1270 (propylene), may also be used. The GWP of R1270 is 3, which is lower than that of HFO-1234yf, but its flammability is higher than that of HFO-1234yf. (3) Also, a mixture containing at least one of halogenated hydrocarbons having a carbon-carbon double bond in the composition or hydrocarbons having a carbon-carbon double bond in the composition, for example, a mixture of HFO-1234yf and R32 may be used. The above-mentioned HFO-1234yf is a low-pressure refrigerant and tends to cause large pressure loss, which may lead to a decrease in the performance of the refrigeration cycle (especially the evaporator). Therefore, in practice, it is preferable to use a mixture with R32 or R41, which are higher-pressure refrigerants than HFO-1234yf.

[0133] The operation of the compressor 300 is as follows. 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 electric motor 100 is driven by supplying a current to the windings 2, the shaft 4 rotates together with the rotor 5. Then, the rolling piston 304 fitted to the shaft 4 rotates eccentrically within the cylinder chamber 303, and the refrigerant is compressed within the cylinder chamber 303.

[0134] The refrigerant compressed in the cylinder chamber 303 passes through the discharge mufflers 308 and 309, and further passes through the through holes 56 and 57 (FIG. 1) of the rotor 5, and the through hole 16 and the recess 19 (FIG. 3) of the stator 1, and rises inside the sealed container 307. The refrigerant that has risen inside the sealed container 307 is discharged from the discharge pipe 312 and supplied to the high pressure side of the refrigeration cycle.

[0135] Although the refrigerant compressed in the cylinder chamber 303 contains refrigeration oil, when the refrigerant passes through the through holes 56, 57 of the rotor 5 or the through hole 16 and the recess 19 of the stator 1, separation of the refrigerant and the refrigeration oil is promoted, and the refrigeration oil is prevented from flowing into the discharge pipe 312.

[0136] The electric motor 100 described in each embodiment can suppress a rise in temperature of the winding 2, and therefore the compressor 300 can have high reliability for a long period of time.

[0137] <Refrigeration cycle equipment> Next, a refrigeration cycle apparatus 400 to which the electric motor of each embodiment can be applied will be described. Fig. 19 is a diagram showing the configuration of the refrigeration cycle apparatus 400. The refrigeration cycle apparatus 400 is an air conditioner here, but may also be, for example, a refrigerator.

[0138] The refrigeration cycle apparatus 400 includes the compressor 300, a four-way valve 401 serving as a switching valve, a condenser 402 for condensing the refrigerant, a pressure reducing device 403 for reducing the pressure of the refrigerant, and an evaporator 404 for evaporating the refrigerant.

[0139] The compressor 300, the condenser 402, the pressure reducing device 403, and the evaporator 404 are connected by a refrigerant pipe 407 to form a refrigerant circuit. The compressor 300 also includes an outdoor fan 405 facing the condenser 402, and an indoor fan 406 facing the evaporator 404.

[0140] The operation of the refrigeration cycle apparatus 400 is as follows. The compressor 300 compresses the sucked refrigerant and sends it out as a high-temperature, high-pressure refrigerant gas. The four-way valve 401 switches the flow direction of the refrigerant, and during cooling operation, the refrigerant sent out from the compressor 300 flows into the condenser 402, as shown by the solid line in Fig. 19.

[0141] The condenser 402 exchanges heat between the refrigerant sent from the compressor 300 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.

[0142] The evaporator 404 exchanges heat between the low-temperature, low-pressure liquid refrigerant sent from the pressure reducing device 403 and the 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 to the room by the indoor fan 406.

[0143] During heating operation, the four-way valve 401 sends the refrigerant sent from the compressor 300 to the evaporator 404. In this case, the evaporator 404 functions as a condenser, and the condenser 402 functions as an evaporator.

[0144] The reliability of the refrigeration cycle apparatus 400 can be improved by providing the electric motor 100 described in the first to third embodiments as a drive source for the compressor 300. The compressor having the electric motor 100 of the first to third embodiments can also be used in other refrigeration cycle apparatuses.

[0145] Although the preferred embodiments have been specifically described above, the present disclosure is not limited to the above-described embodiments, and various improvements and modifications can be made. [Explanation of symbols]

[0146] 1,1A,1B,1C stator, 2 winding, 3 insulating portion, 4 shaft, 5,5A,5B rotor, 8 shell, 9 split core, 10,10A,10B stator core, 11 yoke, 12 teeth, 12a tooth tip portion, 13 slot, 16 through hole, 17 crimped portion (round crimp), 18 crimped portion (V crimp), 19 recess, 31 insulator, 50,50A,50B rotor core, 51 magnet insertion hole, 52 flux barrier, 53 bridge portion, 55 permanent magnet, 100 electric motor, 101 electromagnetic steel sheet, 102 void , 300 compressor, 301 compression mechanism, 302 cylinder, 307 sealed container, 400 refrigeration cycle device, 401 four-way valve, 402 condenser, 403 pressure reducing device, 404 evaporator, 501 electromagnetic steel plate, 502 void .

Claims

1. A motor used in a compressor, a rotor having an annular rotor core centered on an axis line, the rotor core being made of electromagnetic steel plates laminated in the direction of the axis line and fixed by crimping, and a permanent magnet attached to the rotor core; a stator core that is fixed to the inside of the compressor shell and surrounds the rotor core, the stator core being made of electromagnetic steel plates that are laminated in the axial direction and fixed by crimping, and a winding that is wound around the stator core and made of aluminum wire; Equipped with The stator core has a recess on its outer periphery that defines a passage for a coolant between the stator core and an inner periphery of the shell, The coolant flowing through the recess passes through the gaps between the electromagnetic steel sheets of the stator core and the windings, a crimping depth of the electromagnetic steel sheets of the stator core is greater than a crimping depth of the electromagnetic steel sheets of the rotor core, a gap L1 between the electromagnetic steel sheets of the stator core and a gap L2 between the electromagnetic steel sheets of the rotor core satisfy L1>L2, A lamination space factor O1 of the electromagnetic steel sheets of the stator core and a lamination space factor O2 of the electromagnetic steel sheets of the rotor core satisfy O1<O2. Electric motor.

2. A thickness T1 of the electromagnetic steel sheet of the stator core and a thickness T2 of the electromagnetic steel sheet of the rotor core satisfy T1<T2.

2. The electric motor according to claim 1.

3. A thickness T1 of the electromagnetic steel sheets of the stator core and a thickness T2 of the electromagnetic steel sheets of the rotor core satisfy T1<T2<4×T1.

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

4. the rotor core has a magnet insertion hole in which the permanent magnet is disposed, and a bridge portion formed between the magnet insertion hole and the rotor core, The bridge portion has a radial width W centered on the axis, The width W and the thickness T1 of the electromagnetic steel sheet of the stator core satisfy W<T1.

4. An electric motor according to any one of claims 1 to 3.

5. In the Epstein test, when a sinusoidal magnetic flux density change with a frequency of 50 Hz and a maximum magnetic flux density of 1.5 T was induced, An iron loss density W1 per unit weight of the electromagnetic steel sheets of the stator core and an iron loss density W2 per unit weight of the electromagnetic steel sheets of the rotor core satisfy W1<W2.

5. An electric motor according to any one of claims 1 to 4.

6. A silicon content S1 of the electromagnetic steel sheets of the stator core and a silicon content S2 of the electromagnetic steel sheets of the rotor core satisfy S1>S2.

6. An electric motor according to any one of claims 1 to 5.

7. The stator core has a through hole formed from one end to the other end in the axial direction of the stator core.

7. An electric motor according to any one of claims 1 to 6.

8. The stator core has an annular yoke centered on the axis line and teeth extending from the yoke toward the axis line, The through hole is formed in the yoke.

8. The electric motor according to claim 7.

9. The winding is wound around the stator core via an insulating portion, The through hole is exposed at an end surface of the stator core in the axial direction and is not blocked by the insulating portion.

9. The electric motor according to claim 7 or 8.

10. Coils of different layers of the winding cross each other on one end surface of the tooth in the axial direction.

9. The electric motor according to claim 8.

11. The stator core has an annular yoke centered on the axis line and teeth extending from the yoke toward the axis line, The windings are wound around the teeth in a salient pole concentrated winding manner.

11. An electric motor according to any one of claims 1 to 10.

12. The windings are wound around the teeth in an aligned manner.

12. The electric motor according to claim 11.

13. The stator core has a plurality of split cores assembled in an annular shape.

13. An electric motor according to any one of claims 1 to 12.

14. An electric motor according to any one of claims 1 to 13; a compression mechanism driven by the electric motor; A compressor equipped with

15. A compressor comprising the compressor according to claim 14, a condenser, a pressure reducing device, and an evaporator. Refrigeration cycle equipment.

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