Stator, electric motor, compressor, refrigeration cycle device, and method for manufacturing stator

Abstract

A stator, according to the present invention, comprises: an outer periphery extending in the peripheral direction about a center axis; and a stator core which includes a plurality of slots arrayed in the peripheral direction and in which the outer periphery thereof is fixed to the inner side of a shell having a cylindrical shape. At the outer periphery of the stator core, a first notch portion, two second notch portions, and two third notch portions are formed. The two second notch portions are formed on both sides of the first notch portion in the peripheral direction, and the center of the first notch portion and a center of each of the second notch portions in the peripheral direction form a 90-degree angle relative to the center axis. The two third notch portions are formed on both sides of a line passing through the center axis and the center of the first notch portion. A first contact portion in contact with the shell is formed between the two third notch portions. When D1 is defined as the shortest distance to the slot, from among the plurality of slots, closest to the first contact portion, and D2 is defined as the shortest distance to the slot, from among the plurality of slots, closest to the third notch portion, 1.00 ≤ D1 / D2 ≤ 1.60 is satisfied.

Description

[Technical Field]

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

[0002] The stator of an electric motor has a stator core made of laminated core sheets. The core sheets are formed by punching out electromagnetic steel sheets. Patent Document 1 discloses a stator core with five notches formed on the outer periphery to reduce the material cost of the core sheets. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Patent No. 4717089 (see Figures 6-7) Summary of the Invention [Problem to be solved by the invention]

[0004] In the electric motor used in the compressor, the outer periphery of the stator core is fixed to the shell of the compressor, so depending on the arrangement of the notches, magnetic flux leakage from the stator core to the shell may occur, reducing the efficiency of the electric motor.

[0005] The present disclosure aims to reduce material costs and suppress a decrease in motor efficiency. [Means for solving the problem]

[0006] The stator disclosed herein is a stator core having an outer periphery extending circumferentially around a central axis and a plurality of slots arranged circumferentially, the outer periphery of which is fixed inside a cylindrical shell. The outer periphery of the stator core is formed with a first notch, two second notches, and two third notches. The two second notches are formed on both sides of the first notch in the circumferential direction, and the circumferential center of the first notch and the circumferential center of each second notch form a 90-degree angle with respect to the central axis. The two third notches are formed on both sides of a line passing through the central axis and the center of the first notch. A first contact portion that contacts the shell is formed between the two third notches. The first contact portion is located on the line. The shortest distance from the first contact portion to the slot closest to the first contact portion among the plurality of slots is defined as D1, and the shortest distance from each third notch portion to the slot closest to the third notch portion among the plurality of slots is defined as D2. Let the shortest distance from each second notch portion to the slot closest to the second notch portion among the plurality of slots be D3, and the shortest distance from the first notch portion to the slot closest to the first notch portion among the plurality of slots be D4. 1.00 < D1 / D2≦1.60 Furthermore, D2 > D4 and 0.617 ≤ D4 / D3 ≤ 0.882, D2 = D4 and 0.809 ≤ D4 / D3 ≤ 1.000, or D2 < D4 and 0.904 ≤ D4 / D3 ≤ 1.237 hold. [Effects of the Invention]

[0007] In the present disclosure, first, second, and third notches are formed on the outer periphery of the stator core, which reduces material waste during the punching process of the core sheet that constitutes the stator core and reduces material costs. Furthermore, because the shortest distances D1 and D2 satisfy 1.00≦D1 / D2≦1.60, magnetic flux leakage to the shell and iron loss can be reduced. In other words, material costs can be reduced and a decrease in motor efficiency can be suppressed. [Brief explanation of the drawings]

[0008]

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Figure 17

[0009] Embodiment 1 <Motor configuration> Fig. 1 is a cross-sectional view showing an electric motor 3 according to a first embodiment. The electric motor 3 according to the first embodiment is incorporated into, for example, a compressor 500 (Fig. 16). The electric motor 3 has a rotatable rotor 5 and an annular stator 1 surrounding the rotor 5. An air gap is provided between the stator 1 and the rotor 5.

[0010] Hereinafter, the direction of the central axis Ax, which is the center of rotation of the rotor 5, will be referred to as the "axial direction." The circumferential direction centered on the central axis Ax will be referred to as the "circumferential direction." The radial direction centered on the central axis Ax will be referred to as the "radial direction." Note that FIG. 1 is a cross section perpendicular to the axial direction.

[0011] <Rotor configuration> FIG. 2 is a cross-sectional view showing the rotor 5. The rotor 5 has a rotor core 50 and permanent magnets 55 embedded in the rotor core 50. The rotor core 50 has a cylindrical shape centered on a central axis Ax. The rotor core 50 is formed by stacking a plurality of core sheets in the axial direction and fixing them together by caulking, rivets, or the like. The core sheets are, for example, electromagnetic steel sheets. The thickness of the core sheets is, for example, 0.1 to 1.0 mm.

[0012] A center hole 53 is formed in the radial center of the rotor core 50. A shaft 60 is fixed by press fitting into the center hole 53. The center axis of the shaft 60 is the above-mentioned center axis Ax.

[0013] The rotor core 50 has a plurality of magnet insertion holes 51 along its outer periphery. Here, six magnet insertion holes 51 are arranged at equal intervals in the circumferential direction. One permanent magnet 55 is arranged in each magnet insertion hole 51.

[0014] One permanent magnet 55 constitutes one magnetic pole. Since there are six permanent magnets 55, the rotor 5 has six poles. However, the number of poles of the rotor 5 is not limited to six, as long as it is two or more. Furthermore, two or more permanent magnets 55 may be arranged in one magnet insertion hole 51, and one magnetic pole may be constituted by the two or more permanent magnets 55.

[0015] The circumferential center of each magnet insertion hole 51 is the pole center C. Here, the magnet insertion holes 51 extend in a direction perpendicular to a straight line passing through the pole center C and the central axis Ax (i.e., the pole center line), but they may also extend in a V-shape that convexly faces radially inward. The space between adjacent magnet insertion holes 51 is an inter-pole portion M.

[0016] The permanent magnets 55 are flat, with a width in the circumferential direction and a thickness in the radial direction. The permanent magnets 55 are rare earth magnets, more specifically, neodymium rare earth magnets containing neodymium (Nd), iron (Fe), and boron (B). The permanent magnets 55 are magnetized in the thickness direction. The magnetization directions of adjacent permanent magnets 55 in the circumferential direction are opposite to each other.

[0017] Flux barriers 52 are formed at both circumferential ends of the magnet insertion holes 51. The flux barriers 52 are gaps that extend radially from the circumferential ends of the magnet insertion holes 51 toward the outer periphery of the rotor core 50. The flux barriers 52 act to reduce leakage magnetic flux between adjacent magnetic poles.

[0018] Although not shown, through holes may be formed radially inward of the magnet insertion holes 51 of the rotor core 50. The through holes are used as passages for the refrigerant of the compressor or as insertion holes for rivets, etc. The number and arrangement of the through holes are arbitrary.

[0019] <Stator configuration> As shown in FIG. 1, the stator 1 has an annular stator core 10 centered on a central axis Ax, and a coil 20 wound around the stator core 10. The stator core 10 is formed by stacking a plurality of core sheets in the axial direction and fixing them together by caulking or the like. The core sheets are, for example, electromagnetic steel sheets. The thickness of the core sheets is, for example, 0.1 to 1.0 mm.

[0020] The stator core 10 has an annular core back 11 and a plurality of teeth 12 extending radially inward from the core back 11. The outer periphery of the core back 11 is fitted into the inner circumferential surface of a cylindrical shell 40. The shell 40 is part of a sealed container 507 of a compressor 500 (FIG. 16).

[0021] The teeth 12 are formed at equal intervals in the circumferential direction. Each tooth 12 has a tooth tip 12a on its radially inner side that faces the rotor 5. The number of teeth 12 is 18 in this example, but may be any number equal to or greater than two.

[0022] Slots 13 are formed between adjacent teeth 12. Each slot 13 has a slot opening 13a adjacent to the tip 12a of the tooth 12, and extends radially outward from the slot opening 13a. The number of slots 13 is the same as the number of teeth 12, which is 18 in this example. A coil 20 is housed in each slot 13.

[0023] The coil 20 is wound around the teeth 12 via an insulating portion (not shown) and housed in the slot 13. The coil 20 may be wound by either distributed winding or concentrated winding. The coil 20 is made of copper wire or aluminum wire.

[0024] The insulating portion provided between the coil 20 and the teeth 12 is made of a resin such as PBT (polybutylene terephthalate) or PET (polyethylene terephthalate). Alternatively, an insulating film may be used.

[0025] Five notches are formed in the circumferential direction on the outer periphery of the core back 11. More specifically, one notch 21, two notches 22, and two notches 23 are formed on the outer periphery of the core back 11.

[0026] The cutouts 21, 22, and 23 all extend linearly in a plane perpendicular to the central axis Ax. In other words, the cutouts 21, 22, and 23 are all flat surfaces parallel to the central axis Ax.

[0027] 3 is a diagram for explaining the arrangement of the notches 21, 22, and 23 in the stator core 10. The notch 21 is formed in one location on the outer periphery of the core back 11 (here, on the lower side in FIG. 3).

[0028] The notch portions 22 are formed on both circumferential sides of the notch portion 21. The circumferential center 21a of the notch portion 21 and the circumferential center 22a of the notch portion 22 form an angle of 90 degrees with respect to the central axis Ax. In other words, a straight line L1 passing through the center 21a of the notch portion 21 and the central axis Ax is perpendicular to a straight line L2 passing through the center 22a of the notch portion 22 and the central axis Ax.

[0029] The notch portion 23 is formed on the opposite side of the central axis Ax to the notch portion 21. The notch portions 23 are formed on both sides of a straight line L1 that passes through the center 21a of the notch portion 21 and the central axis Ax.

[0030] 3, the circumferential center 22a of the cutout portion 22 and the circumferential center 23a of the cutout portion 23 form an angle of 60 degrees with respect to the central axis Ax. However, the angle is not limited to 60 degrees, and may be any angle less than 90 degrees.

[0031] The notch 21 is also referred to as a "first notch," the notch 22 as a "second notch," and the notch 23 as a "third notch."

[0032] On the outer periphery of the core back 11, a contact portion 15 is formed between the notch portion 21 and the notch portion 22. A contact portion 16 is formed between the notch portion 22 and the notch portion 23. A contact portion 17 is formed between the two notch portions 23. The contact portions 15, 16, and 17 are contact surfaces that come into contact with the inner circumferential surface of the shell 40.

[0033] Each of the contact portions 15, 16, and 17 extends in an arc shape on a plane perpendicular to the central axis Ax. In other words, each of the contact portions 15, 16, and 17 is part of a cylindrical surface centered on the central axis Ax.

[0034] Contact portions 15 and 16 are formed on both sides of straight line L1. One contact portion 17 is formed on straight line L1. Contact portion 17 is also referred to as the "first contact portion." Contact portion 16 is also referred to as the "second contact portion," and contact portion 15 is also referred to as the "third contact portion."

[0035] The shortest distance from contact portion 17 to the slot 13 closest to this contact portion 17 is defined as D1. The shortest distance from contact portion 15 to the slot 13 closest to this contact portion 15 is equal to the above D1. Also, the shortest distance from contact portion 16 to the slot 13 closest to this contact portion 16 is equal to the above D1.

[0036] Meanwhile, D2 denotes the shortest distance from the notch 23 to the slot 13 closest to this notch 23. D3 denotes the shortest distance from the notch 22 to the slot 13 closest to this notch 22. D4 denotes the shortest distance from the notch 21 to the slot 13 closest to this notch 21.

[0037] The contact portions 15, 16, and 17 form arcs of a circle centered on the central axis Ax, while the notches 21, 22, and 23 correspond to chords of the circle. Therefore, the shortest distances D2, D3, and D4 are all shorter than the shortest distance D1.

[0038] The shortest distance D1 and the shortest distance D2 satisfy the relationship 1.00≦D1 / D2≦1.60, for reasons that will be explained later.

[0039] <Manufacturing method> Next, a method for manufacturing the electric motor 3 will be described. Fig. 4 is a flowchart showing a method for manufacturing the electric motor 3. First, a press machine is used to punch out a core sheet 101 for the stator core 10 from an electromagnetic steel sheet (step S100). The shape of the core sheet 101 is the same as the shape of the stator core 10 described with reference to Figs. 1 and 3.

[0040] Fig. 5 is a diagram showing an electromagnetic steel sheet 100 from which a core sheet 101 is punched. As shown in Fig. 5, the electromagnetic steel sheet 100 is a strip-shaped steel sheet that is long in one direction and has a width W1 in a direction perpendicular to the longitudinal direction.

[0041] The core sheets 101 are punched into 2N rows (N is an integer) from the electromagnetic steel sheet 100. Fig. 5 shows a case where the core sheets 101 are punched into two rows (i.e., when N = 1) from the electromagnetic steel sheet 100, but they may also be punched into four rows, six rows, etc.

[0042] Core sheets 101 belonging to the same row are punched out so that their cutout portions 22 face each other. The center-to-center distance between core sheets 101 belonging to the same row is referred to as pitch P1. Core sheets 101 in the first row and core sheets 101 in the second row are punched out with a positional shift of half the pitch P1 (i.e., P1 / 2) in the longitudinal direction of the electromagnetic steel sheet 100.

[0043] The core sheets 101 in the first row and the core sheets 101 in the second row are positioned 180 degrees inverted from each other. In other words, the cutouts 23 of the core sheets 101 in the first row and the cutouts 23 of the core sheets 101 in the second row are positioned opposite each other. The cutouts 21 of each core sheet 101 face the width-direction end 100E of the electromagnetic steel sheet 100.

[0044] In this way, the cutouts 23 of the core sheets 101 in the first row face the cutouts 23 of the core sheets 101 in the second row, and because these cutouts 23 are linear, the centers of the core sheets 101 in the first row and the second row can be punched out closer to each other in the width direction. This allows the width W1 of the electromagnetic steel sheet 100 to be narrowed.

[0045] In the example shown in Figure 5, two rows of core sheets 101 are punched out from the electromagnetic steel sheet 100, but if four or more rows are punched out, i.e., if N is 2 or more, the two rows of core sheets 101 shown in Figure 5 are punched out in a pattern with N sets lined up in the width direction.

[0046] 5, core sheet 101 for stator core 10 is punched out from electromagnetic steel sheet 100, but core sheet 101 for rotor core 50 may be punched out from the area inside core sheet 101. In this way, material costs can be further reduced.

[0047] After punching out the core sheets 101 from the electromagnetic steel sheets 100 in this manner, the core sheets 101 are stacked in the axial direction and fixed by caulking or the like to form the stator core 10 (step S101 in FIG. 4). After that, an insulating portion (not shown) is formed on the stator core 10 (step S102), and the coil 20 is wound around it (step S103). This completes the stator 1. Steps S100 to S103 correspond to a manufacturing method of the stator 1.

[0048] In parallel with steps S100 to S103, the rotor 5 is manufactured. First, a core sheet for the rotor core 50 is punched out from an electromagnetic steel sheet (step S200). Note that this step can be omitted if the core sheet for the rotor core 50 is punched out together with the core sheet 101 for the stator core 10 from the electromagnetic steel sheet 100 shown in FIG.

[0049] Next, the core sheets are stacked in the axial direction and fixed by caulking or the like to form the rotor core 50 (step S201). After that, permanent magnets 55 are attached to the magnet insertion holes 51 of the rotor core 50 (step S202). Balance weights may also be attached if necessary. This completes the rotor 5.

[0050] The rotor 5 thus assembled is then fitted inside the stator 1 (step S104), thereby completing the electric motor 3.

[0051] After the electric motor 3 is completed, it is fixed to the inside of the shell 40 by shrink fitting or the like. Specifically, the electric motor 3 is inserted into the inside of the shell 40 whose inner diameter has been expanded by heating, and then cooled. As a result, the contact portions 15, 16, and 17 on the outer periphery of the stator core 10 are fixed to the inside of the shell 40.

[0052] <Comparative Example> Next, a comparative electric motor 3C to be compared with the electric motor 3 of the first embodiment will be described. Fig. 6 is a diagram showing the comparative electric motor 3C. The comparative electric motor 3C has four notches 25 on the outer periphery of the stator core 10. The notches 25 are formed at equal intervals in the circumferential direction. The circumferential centers 25a of adjacent notches 25 form an angle of 90 degrees with respect to the central axis Ax.

[0053] Arc-shaped contact portions 18 are formed between circumferentially adjacent cutout portions 25. That is, four contact portions 18 are formed at equal intervals in the circumferential direction. In other respects, electric motor 3C of the comparative example is configured similarly to electric motor 3 of the first embodiment.

[0054] Fig. 7 is a plan view showing an electromagnetic steel sheet 110 from which core sheets 102 constituting a stator core 10 of a comparative example are punched out. As shown in Fig. 7, core sheets 102 are punched out from electromagnetic steel sheet 110 in two rows.

[0055] Core sheets 102 belonging to the same row are punched out so that their cutout portions 25 face each other. The center-to-center distance between core sheets 102 belonging to the same row is referred to as pitch P2. Core sheets 102 in the first row and core sheets 102 in the second row are punched out with a positional shift of half the pitch P2 (i.e., P2 / 2) in the longitudinal direction of the electromagnetic steel sheet 110.

[0056] In the comparative example, the contact portions 18 of the core sheets 102 in the first row and the contact portions 18 of the core sheets 102 in the second row face each other, and these contact portions 18 are arc-shaped. Therefore, it is difficult to narrow the widthwise distance between the centers of the core sheets 102 in the first row and the second row.

[0057] In contrast, in Embodiment 1, as shown in FIG. 5, since the linear notch 23 of the core sheet 101 in the first row and the linear notch 23 of the core sheet 101 in the second row face each other, the width direction distance between the center of the core sheet 101 in the first row and the center of the core sheet 101 in the second row can be shortened. As a result, the width W1 of the electromagnetic steel sheet 100 can be narrowed, and the material cost can be reduced.

[0058] <Optimal range of D1 / D2> Here, as described above, the distances D2, D3, D4 from the notch portions 23, 22, 21 to the slot 13 are shorter than the shortest distance D1 from the contact portion 17 to the slot 13. If the distances D2, D3, D4 are too short, a portion with a narrow radial width will occur in the core back 11, and magnetic flux concentration will occur. When magnetic flux concentration occurs in the core back 11, magnetic flux leakage to the shell 40 may occur, and the iron loss may increase.

[0059] Therefore, here, the ratio D1 / D2 of the shortest distance D1 to the shortest distance D2 was changed, and the change in iron loss in the shell 40 was examined. The shortest distances D3, D4 are set to be the same as the shortest distance D2 (D2 = D3 = D4).

[0060] FIG. 8 is a graph showing the change in iron loss when the ratio D1 / D2 of the shortest distance D1 to the shortest distance D2 is changed. The horizontal axis represents D1 / D2, and the vertical axis represents the iron loss in the shell 40. The iron loss is represented by a relative value based on the iron loss when D1 / D2 = 1.60 (100%).

[0061] In the analysis, the outer diameter of the stator core 10 was 159.5 mm, and the shortest distance D1 was 14.95 mm As such, the shortest distance D2 was changed from 6.45 mm to 14.95 mm. Both of the shortest distances D3, D4 were the same as the shortest distance D2.

[0062] As shown in Fig. 8, as D1 / D2 increases, the iron loss increases accordingly. In particular, when D1 / D2 ranges from 1.00 to 1.60, the increase in iron loss is nearly linear and the slope is gentle, while the increase rate becomes large after D1 / D2 exceeds 1.60. The point A where D1 / D2 = 1.60 corresponds to the point where the curvature changes.

[0063] Fig. 9(A) is a diagram showing the analysis result of the magnetic flux distribution in the stator core 10 when D1 / D2 = 1.60 (point A in Fig. 8). Fig. 9(B) is a diagram showing the analysis result of the magnetic flux distribution in the stator core 10 when D1 / D2 = 1.79 (point B in Fig. 8).

[0064] When D1 / D2 = 1.60 (Fig. 9(A)), no magnetic flux leakage to the shell 40 occurs, or even if it occurs, it is at a level that does not cause a significant increase in the iron loss of the shell 40. On the other hand, when D1 / D2 = 1.79 (Fig. 9(B)), the magnetic flux leakage to the shell 40 is at a level that causes a significant increase in the iron loss of the shell 40, as shown by, for example, the symbol E1.

[0065] This is because the larger D1 / D2 is, the narrower the width of the core back 11 in the part where the notch 23 is formed, resulting in magnetic flux concentration in this part and a part of the magnetic flux flowing into the shell 40.

[0066] From the results shown in Fig. 8 and Figs. 9(A) and (B), it can be seen that it is desirable that the ratio D1 / D2 of the shortest distance D1 to the shortest distance D2 is within the range of 1.00 ≤ D1 / D2 ≤ 1.60.

[0067] <Optimal range of D4 / D3> Next, the ratio D4 / D3 of the shortest distance D4 from the notch 21 to the slot 13 and the shortest distance D3 from the notch 22 to the slot 13 will be described. In the analysis shown in FIG. 8 above, the shortest distances D4, D3, and D2 from the notches 21, 22, and 23 to the slot 13 were set equal, but here, depending on the magnitude relationship between the shortest distance D4 from the notch 21 to the slot 13 and the shortest distance D2 from the notch 23 to the slot 13, the analysis is carried out by dividing it into three cases: D2 > D4, D2 = D4, and D2 < D4.

[0068] FIG. 10 is a graph showing the change in iron loss when the ratio D4 / D3 of the shortest distance D4 and the shortest distance D3 is changed in the case of D2 > D4. The horizontal axis represents D4 / D3, the left vertical axis represents the iron loss in the shell 40, and the right vertical axis represents the amount of steel sheet used. The iron loss is represented as a relative value based on the iron loss when D4 / D3 = 1.00 (100%). The amount of steel sheet used represents the ratio of the change in the width W1 of the electromagnetic steel sheet (FIG. 5) to the width W2 of the electromagnetic steel sheet in the comparative example ((W1 - W2) / W2).

[0069] In the analysis, the outer diameter of the stator core 10 is 159.5 mm, the shortest distance D1 is 14.95 mm, the shortest distance D2 is 8.45 mm, the shortest distance D4 is as 7.45 mm, and the shortest distance D3 is changed to 6.45 mm, 7.45 mm, 8.45 mm, 9.45 mm, and 10.45 mm. The ratio D2 / D4 of the shortest distance D2 and the shortest distance D4 is 1.13.

[0070] As shown in FIG. 10, as D4 / D3 increases, the iron loss increases accordingly. In particular, the increase rate of the iron loss after D4 / D3 exceeds 0.882 is large. In other words, the curvature of the curve when D4 / D3 exceeds 0.882 is larger than the curvature of the curve when D4 / D3 is from 0.6I7 to 0.882. The point B where D4 / D3 = 0.882 corresponds to the change point of the curvature. [[ID=I4]]

[0071] The amount of steel sheet used increases as D4 / D3 increases from 0.617 to 0.700, and then decreases when D4 / D3 exceeds 0.700. The amount of steel sheet used is less than that of the comparative example over the entire range of D4 / D3, and the yield is improved.

[0072] Fig. 11(A) is a diagram showing the analysis results of the magnetic flux distribution in the stator core 10 when D4 / D3=0.778 (point A in Fig. 10). Fig. 11(B) is a diagram showing the analysis results of the magnetic flux distribution in the stator core 10 when D4 / D3=0.882 (point B in Fig. 10). Fig. 11(C) is a diagram showing the analysis results of the magnetic flux distribution in the stator core 10 when D4 / D3=1.000 (point C in Fig. 10).

[0073] When D4 / D3=0.778 (FIG. 11(A)) and when D4 / D3=0.882 (FIG. 11(B)), magnetic flux leakage to the shell 40 does not occur, or even if it does occur, it is at a level that does not cause a significant increase in iron loss in the shell 40. On the other hand, when D4 / D3= 1. In the case of 000 (FIG. 11C), the magnetic flux leakage to the shell 40 is at a level that causes a significant increase in iron loss in the shell 40, as shown by the symbols E1 and E2, for example.

[0074] This is because D2>D4, so the width of the core back 11 is narrower at the portion where the cutout portion 22 is formed, and the larger D4 / D3 becomes, the narrower the width of the core back 11 becomes at the portion where the cutout portion 22 is formed. As a result, magnetic flux concentrates at these portions, and some of the magnetic flux flows into the shell 40.

[0075] From the results shown in Figure 10 and Figures 11(A), (B), and (C), it can be seen that when D2>D4, it is desirable that the ratio D4 / D3 of the shortest distance D4 to the shortest distance D3 be in the range 0.617≦D4 / D3≦0.882.

[0076] Fig. 12 is a graph showing the change in iron loss when the ratio D4 / D3 of the shortest distance D4 to the shortest distance D3 is changed when D2 = D4. The horizontal axis represents D4 / D3, the left vertical axis represents iron loss in the shell 40, and the right vertical axis represents the amount of steel sheet used. Iron loss is expressed as a relative value, with the iron loss when D4 / D3 = 1.000 being the reference (100%). The amount of steel sheet used is as described with reference to Fig. 10.

[0077] In the analysis, the outer diameter of the stator core 10 is 159.5 mm, and the shortest distance D1 is 14.95 mm , the shortest distance D2 is 8.45 mm , the shortest distance D4 is 8.45 mm The shortest distance D3 is changed to 6.45 mm, 7.45 mm, 8.45 mm, 9.45 mm, and 10.45 mm.

[0078] As shown in Figure 12, as D4 / D3 increases, iron loss also increases. In particular, the rate of increase in iron loss is large once D4 / D3 exceeds 1.000. In other words, the curvature of the curve once D4 / D3 exceeds 1.000 is larger than the curvature of the curve from D4 / D3 0.809 to 1.000. Point B, where D4 / D3 = 1.000, corresponds to the point where the curvature changes.

[0079] The amount of steel sheet used decreases as D4 / D3 increases. Across the entire range of D4 / D3, the amount of steel sheet used is less than in the comparative example, and the yield is improved.

[0080] Fig. 13(A) is a diagram showing the analysis results of the magnetic flux distribution in the stator core 10 when D4 / D3=0.894 (point A in Fig. 12). Fig. 13(B) is a diagram showing the analysis results of the magnetic flux distribution in the stator core 10 when D4 / D3=1.000 (point B in Fig. 12). Fig. 13(C) is a diagram showing the analysis results of the magnetic flux distribution in the stator core 10 when D4 / D3=1.134 (point C in Fig. 12).

[0081] When D4 / D3 = 0.894 (Fig. 13(A)) and when D4 / D3 = 1.000 (Fig. 13(B)), there is no magnetic flux leakage to the shell 40, or even if there is magnetic flux leakage, it is at a level that does not cause a significant increase in the iron loss of the shell 40. On the other hand, when D4 / D3 = 1.134 (Fig. 13(C)), the magnetic flux leakage to the shell 40 is at a level that causes a significant increase in the iron loss in the shell 40, as indicated by, for example, the symbol E1.

[0082] This is because as D4 / D3 increases, the width of the core back 11 becomes narrower at the portion where the notch 22 is formed, resulting in magnetic flux concentration at this portion and causing a part of the magnetic flux to flow into the shell 40.

[0083] From the results shown in Fig. 12 and Figs. 13(A), (B), and (C), it can be seen that when D2 = D4, it is desirable that the ratio D4 / D3 of the shortest distance D4 to the shortest distance D3 is within the range of 0.809 ≤ D4 / D3 ≤ 1.000.

[0084] Fig. 14 is a graph showing the change in iron loss when the ratio D4 / D3 of the shortest distance D4 to the shortest distance D3 is changed in the case of D2 < D4. The horizontal axis represents D4 / D3, the left vertical axis represents the iron loss in the shell 40, and the right vertical axis represents the amount of steel sheet used. The iron loss is represented as a relative value based on the iron loss when D4 / D3 = 1.237 (100%). The amount of steel sheet used is as described with reference to Fig. 10.

[0085] In the analysis, the outer diameter of the stator core 10 is 159.5 mm, the shortest distance D1 is 14.95 mm , the shortest distance D2 is 8.45 mm , the shortest distance D4 is 10.45 mm , and the shortest distance D3 is changed to 6.45 mm, 7.45 mm, 8.45 mm, 9.45 mm, and 10.45 mm.

[0086] As shown in Fig. 14, when D4 / D3 increases, the iron loss increases accordingly. In particular, the increase rate of iron loss is large after D4 / D3 exceeds 1.237. In other words, the curvature of the curve after D4 / D3 exceeds 1.237 is larger than the curvature of the curve from D4 / D3 = 0.904 to 1.237. The point B where D4 / D3 = 1.237 corresponds to the point where the curvature changes.

[0087] The amount of steel sheet used decreases as D4 / D3 increases. The amount of steel sheet used is less than that of the comparative example over the entire range of D4 / D3, and the yield is improved.

[0088] Fig. 15(A) is a diagram showing the analysis result of the magnetic flux distribution in the stator core 10 when D4 / D3 = 1.104 (point A in Fig. 14). Fig. 15(B) is a diagram showing the analysis result of the magnetic flux distribution in the stator core 10 when D4 / D3 = 1.237 (point B in Fig. 14). Fig. 15(C) is a diagram showing the analysis result of the magnetic flux distribution in the stator core 10 when D4 / D3 = 1.403 (point C in Fig. 14).

[0089] When D4 / D3 = 1.104 (Fig. 15(A)) and when D4 / D3 = 1.237 (Fig. 15(B)), there is no magnetic flux leakage to the shell 40, or even if there is magnetic flux leakage, it is at a level that does not cause a significant increase in the iron loss of the shell 40. On the other hand, when D4 / D3 = 1.403 (Fig. 15(C)), the magnetic flux leakage to the shell 40 is at a level that causes a significant increase in the iron loss of the shell 40, as indicated by, for example, the symbol E1.

[0090] This is because as D4 / D3 increases, the width of the core back 11 becomes narrower at the part where the notch 22 is formed, so magnetic flux concentration occurs at this part, and a part of the magnetic flux flows into the shell 40.

[0091] From the results shown in Fig. 14 and Figs. 15(A), (B), and (C), it can be seen that when D2 < D4, it is desirable that the ratio D4 / D3 of the shortest distance D4 to the shortest distance D3 is within the range of 0.904 ≤ D4 / D3 ≤ 1.237.

[0092] In the analysis described with reference to FIGS. 10, 12, and 14, the longest of the shortest distances D2, D3, and D4 is defined as Dmax, and the shortest is defined as Dmin, and the relationship between Dmax and Dmin is satisfied. m The measurement was carried out within a range that satisfied the condition {D1 / Dmax)-(D1 / Dmax)}≦0.8872.

[0093] <Effects of the embodiment> As described above, the stator 1 of the first embodiment has, on the outer periphery of the stator core 10, the notch 21 as a first notch, two notches 22 as second notches, and two notches 23 as third notches. The notch 22 is formed on both circumferential sides of the notch 21, and the centers 21a, 22a of the notches 21, 22 form an angle of 90 degrees with respect to the central axis Ax. The notch 23 is formed on both sides of the straight line L1 that passes through the central axis Ax and the center 21a of the notch 21, and the contact portion 17 as a first contact portion is formed between these two notches 23. If the shortest distance from the contact portion 17 to the slot 13 is D1 and the shortest distance from the notch 23 to the slot 13 is D2, then 1.00≦D1 / D2≦1.60 holds.

[0094] This configuration allows core sheets 101 that make up stator core 10 to be punched out of electromagnetic steel sheet 100 in 2N rows with a narrow width W1, reducing material costs. Furthermore, because the shortest distances D1 and D2 satisfy 1.00≦D1 / D2≦1.60, magnetic flux leakage to the shell can be reduced, reducing iron loss. In other words, material costs can be reduced while minimizing the decline in motor efficiency.

[0095] Furthermore, if the shortest distance from the notch 22 to the slot 13 is D3 and the shortest distance from the notch 21 to the slot 13 is D4, then D2 > D4 and 0.617 ≦ D4 / D3 ≦ 0.882 hold, which makes it possible to more effectively reduce material costs and prevent a decrease in motor efficiency.

[0096] Also, when D2 = D4 and 0.809 ≤ D4 / D3 ≤ 1.000, it is possible to more effectively reduce the material cost and also suppress the decrease in motor efficiency.

[0097] Also, when D2 < D4 and 0.904 ≤ D4 / D3 ≤ 1.237, it is possible to more effectively reduce the material cost and also suppress the decrease in motor efficiency.

[0098] Also, since the slot 13 is located on the radially inner side (i.e., the central axis Ax side) of the center 17a of the contact portion 17, the shortest distance from the notch portions 23 on both sides of the contact portion 17 to the slot 13 can be increased, and the effect of reducing the magnetic flux leakage to the shell 40 can be enhanced.

[0099] Also, since the tooth 12 is located on the radially inner side of the center 22a in the circumferential direction of the notch portion 22, the shortest distance from the notch portion 22 to the slot 13 can be increased, and the effect of reducing the magnetic flux leakage to the shell 40 can be enhanced.

[0100] Also, since the tooth 12 is located on the radially inner side of the center 23a in the circumferential direction of the notch portion 23, the shortest distance from the notch portion 23 to the slot 13 can be increased, and the effect of reducing the magnetic flux leakage to the shell 40 can be enhanced.

[0101] Also, the manufacturing method of the stator 1 of Embodiment 1 includes a step of punching out the core sheet 101 from the electromagnetic steel sheet 100, a step of laminating the core sheets 101 to form the stator core 10, and a step of winding the coil 20 around the stator core 10. In the step of punching out the core sheet 101, the core sheet 101 is punched out from the electromagnetic steel sheet 100 in 2N rows (N is an integer) and at a constant pitch P in each row, and the punching is performed such that the core sheet 101 in the first row and the core sheet 102 in the second row are shifted by half of the pitch P. Therefore, the core sheet 101 can be punched out from the electromagnetic steel sheet 100 with a narrow width W1, and the material cost can be reduced.

[0102] In particular, in the above-described punching process of the core sheets 101, punching is performed so that the cutout portions 23 of the core sheets 101 in the first row face the cutout portions 23 of the core sheets 101 in the second row, which shortens the distance in the width direction between the centers of the core sheets 101 in the first row and the second row, thereby narrowing the width W1 of the electromagnetic steel sheet 100. This enhances the effect of reducing material costs.

[0103] Embodiment 2 Next, a compressor 500 according to a second embodiment will be described. The compressor 500 according to the second embodiment includes the electric motor 3 according to the first embodiment. Fig. 16 is a cross-sectional view showing the compressor 500. The compressor 500 is a scroll compressor in this example, but is not limited to this.

[0104] The compressor 500 includes a sealed container 507, a compression mechanism 505 disposed within the sealed container 507, an electric motor 3 that drives the compression mechanism 505, a shaft 60 that connects the compression mechanism 505 and the electric motor 3, and a subframe 508 that supports the lower end of the shaft 60.

[0105] The compression mechanism 505 includes a fixed scroll 501 having a spiral portion, a swinging scroll 502 having a spiral portion that forms a compression chamber between the fixed scroll 501 and the spiral portion of the fixed scroll 501, a compliance frame 503 that holds the upper end of the shaft 60, and a guide frame 504 that is fixed to a sealed container 507 and holds the compliance frame 503.

[0106] A suction pipe 510 penetrating the sealed container 507 is press-fitted into the fixed scroll 501. The sealed container 507 is also provided with a discharge pipe 511 that discharges high-pressure refrigerant gas from the fixed scroll 501 to the outside. The discharge pipe 511 communicates with an opening (not shown) provided between the compression mechanism 505 of the sealed container 507 and the electric motor 3.

[0107] The electric motor 3 is fixed to the sealed container 507 by fitting the stator 1 into the sealed container 507. The configuration of the electric motor 3 is as described above. A glass terminal 509 that supplies power to the electric motor 3 is fixed to the sealed container 507 by welding.

[0108] When the electric motor 3 rotates, the rotation is transmitted to the orbiting scroll 502, causing the orbiting scroll 502 to orbit. When the orbiting scroll 502 orbits, the volume of the compression chamber formed by the spiral portion of the orbiting scroll 502 and the spiral portion of the fixed scroll 501 changes. Refrigerant gas is then sucked in through the suction pipe 510, compressed, and discharged through the discharge pipe 511.

[0109] The compressor 500 includes the electric motor 3 of the first embodiment, which is low cost and has high motor efficiency, and therefore the manufacturing cost of the compressor 500 can be reduced and the operating efficiency can be increased.

[0110] Embodiment 3 Next, a refrigeration cycle apparatus 400 according to a third embodiment will be described. The refrigeration cycle apparatus 400 according to the third embodiment includes the compressor 500 according to the second embodiment. Fig. 17 is a diagram showing the refrigeration cycle apparatus 400. The refrigeration cycle apparatus 400 is, for example, an air conditioner, but is not limited thereto.

[0111] The refrigeration cycle device 400 shown in Fig. 17 includes a compressor 401, a condenser 402 for condensing a refrigerant, a pressure reducing device 403 for reducing the pressure of the refrigerant, and an evaporator 404 for evaporating the refrigerant. The compressor 401, the condenser 402, and the pressure reducing device 403 are arranged in a room outer The evaporator 404 is installed in the chamber 410. inner It is provided on the machine 420.

[0112] Compressor 401, condenser 402, pressure reducing device 403, and evaporator 404 are connected by refrigerant piping 407 to form a refrigerant circuit. Compressor 401 is configured as compressor 500 shown in FIG. 16. Refrigeration cycle device 400 also includes an outdoor fan 405 facing condenser 402 and an indoor fan 406 facing evaporator 404.

[0113] The operation of the refrigeration cycle apparatus 400 is as follows. The compressor 401 compresses the refrigerant it has drawn in and sends it out as a 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 air 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.

[0114] The evaporator 404 exchanges heat between the low-temperature, low-pressure liquid refrigerant sent from the pressure reducing device 403 and the indoor air, evaporating the refrigerant and sending it out. The air from which heat has been removed in the evaporator 404 is supplied by the indoor fan 406 into the room, which is the space to be air-conditioned.

[0115] The compressor 401 of the refrigeration cycle device 400 includes the electric motor 3 of the first embodiment, which is low cost and has high motor efficiency, and therefore the manufacturing cost of the refrigeration cycle device 400 can be reduced and the operation efficiency can be increased.

[0116] 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]

[0117] DESCRIPTION OF SYMBOLS 1 stator, 3 electric motor, 5 rotor, 10 stator core, 11 core back, 12 teeth, 13 slot, 15 contact portion (third contact portion), 16 contact portion (second contact portion), 17 contact portion (first contact portion), 20 coil, 21 notch portion (first notch portion), 21a, 22a, 23a center, 22 notch portion (second notch portion), 23 notch portion (third notch portion), 40 shell, 50 rotor core, 51 magnet insertion hole, 55 permanent magnet, 100 electromagnetic steel sheet, 101 core sheet, 102 core sheet, 110 electromagnetic steel sheet, 400 refrigeration cycle device, 401 compressor, 402 Condenser, 403 pressure reducing device, 404 evaporator, 410 roomouter machine, 420 rooms inner machine, 500 compressor, 505 compression mechanism, 507 sealed container.

Claims

1. a stator core having an outer periphery extending in a circumferential direction about a central axis and a plurality of slots arranged in the circumferential direction, the outer periphery of which is fixed inside a cylindrical shell; a first notch, two second notches, and two third notches are formed on the outer periphery of the stator core; the two second notches are formed on both sides of the first notch in the circumferential direction, and the circumferential center of the first notch and the circumferential center of each second notch form an angle of 90 degrees with respect to the central axis; the two third cutout portions are formed on both sides of a straight line passing through the central axis and the center of the first cutout portion, a first contact portion that comes into contact with the shell is formed between the two third cutout portions, and the first contact portion is located on the straight line; The shortest distance from the first contact portion to the slot closest to the first contact portion among the plurality of slots is defined as D1, a shortest distance from each third cutout portion to a slot among the plurality of slots that is closest to the third cutout portion is defined as D2; D3 is the shortest distance from each second cutout portion to a slot among the plurality of slots that is closest to the second cutout portion; If the shortest distance from the first notch portion to the slot closest to the first notch portion among the plurality of slots is D4, 1.00<D1 / D2≦1.60 is satisfied, and further, D2>D4 and 0.617≦D4 / D3≦0.882; D2 = D4 and 0.809 ≤ D4 / D3 ≤ 1.000, or D2<D4 and 0.904≦D4 / D3≦1.237 holds true Stator.

2. Among the plurality of slots, a slot closest to the first contact portion is located on the side of the central axis with respect to the center of the first contact portion in the circumferential direction. The stator according to claim 1 .

3. A tooth formed between two of the plurality of slots is located on the side of the central axis with respect to the center in the circumferential direction of each second cutout portion.

3. A stator according to claim 1 or 2.

4. A tooth formed between two of the plurality of slots is located on the side of the central axis with respect to the center in the circumferential direction of each third cutout portion. A stator according to any one of claims 1 to 3.

5. A stator according to any one of claims 1 to 4; a rotor disposed inside the stator; An electric motor having

6. The electric motor according to claim 5; a compression mechanism driven by the electric motor; the shell enclosing the electric motor and the compression mechanism; A compressor having

7. A compressor having the compressor according to claim 6, a condenser, a pressure reducing device, and an evaporator. Refrigeration cycle equipment.

8. A method for manufacturing a stator according to any one of claims 1 to 4, punching a core sheet from an electromagnetic steel sheet; laminating the core sheets to form the stator core; a step of winding a coil around the stator core; and In the step of punching out the core sheets, the core sheets are punched out from the electromagnetic steel sheet in 2N rows (N is an integer) at a constant pitch P in each row, and punching is performed so that the core sheets in the first row and the core sheets in the second row are shifted by half the pitch P. A method for manufacturing a stator.

9. In the step of punching out the core sheets, punching is performed so that the third notch portion of the core sheet in the first row faces the third notch portion of the core sheet in the second row. The method for manufacturing a stator according to claim 8 .

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