Stators of electric motors, compressors and refrigeration / air conditioning equipment

Abstract

This stator (10) of an electric motor (100) comprises an annular core back part (11), and a plurality of teeth (12) extending radially inward from the core back part (11). The plurality of teeth (12) have a wedge-shaped part (13) that protrudes on both sides in the circumferential direction in a wedge form that becomes thinner as the tip goes forward. In the plurality of teeth (12), a base height Kt, which is the length in the radial direction of a base (15) of the wedge-shaped part (13), and a tip height Ks, which is the length in the radial direction of a circumferential direction tip (16) of the wedge-shaped part (13), satisfy the relationship of 1 < Kt / Ks ≤ 2.85.

Description

[Technical field]

[0001] The present disclosure relates to the shape of a portion in a stator of an electric motor. [Background technology]

[0002] In the stator of an electric motor, the teeth have a wedge-shaped portion that protrudes on both sides in the circumferential direction and is tapered radially toward the tip. The relationship between the height of the tip and the height of the base of the wedge-shaped portion of the teeth not only affects the induced voltage waveform, but also affects parameters related to motor efficiency, such as the torque constant and inductance.

[0003] Patent Document 1 describes a stator of an electric motor having a plurality of teeth with wedge-shaped portions. In Patent Document 1, the root height Kt of the wedge-shaped portion is set within a range of 0.13 to 0.16 times the distance P between the centers of adjacent teeth. Also, in Patent Document 1, the tip height Ks of the wedge-shaped portion is set within a range of 0.017 to 0.035 times the distance P between the centers of adjacent teeth.

[0004] Distance P is calculated by 2×π×R / S using stator radius R and number of slots S. Assume that the inner diameter of the stator is 56 mm (millimeters) and the number of slots is 9. Since the inner diameter is 56 mm, the radius is 28 mm. In this case, in Patent Document 1, the minimum value of root height Kt is 2.54. The minimum value of tip height Ks is 0.33. The maximum value of root height Kt is 3.13. The maximum value of tip height Ks is 0.68. Therefore, Kt / Ks is maximum when the root height Kt is maximum 3.13 and the tip height Ks is minimum 0.33, and Kt / Ks is 9.4. Kt / Ks is minimum when the root height Kt is minimum 2.54 and the tip height Ks is maximum 0.68, and Kt / Ks is 3.7. In other words, in Patent Document 1, 3.7≦Kt / Ks≦9.4. [Prior art documents]

Patent Document

[0005]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0006] In the relationship between the root height Kt and the tip height Ks described in Patent Document 1, it could not be said that the efficiency of the motor was sufficiently high. The present disclosure aims to make the efficiency of the motor higher.

Means for Solving the Problems

[0007] The stator of the motor according to the present disclosure has an annular core back portion, a plurality of teeth portions extending radially inward from the core back portion, the plurality of teeth portions having wedge - shaped portions protruding on both circumferential sides in a wedge shape that becomes thinner toward the tip, and is provided with in the teeth portion, the root height Kt which is the radial length of the root of the wedge - shaped portion and the tip height Ks which is the radial length of the tip of the wedge - shaped portion satisfy the relationship of 1 < Kt / Ks ≤ 2.85.

Effects of the Invention

[0008] In the present disclosure, the root height Kt and the tip height Ks satisfy the relationship of 1 < Kt / Ks ≤ 2.85. Thereby, the efficiency of the motor can be made higher.

Brief Description of the Drawings

[0009] [Figure 1] Configuration diagram of the motor 100 according to Embodiment 1. [Diagram 2] Explanation diagram of the relationship between Kt / Ks and the fundamental wave iron loss. [Diagram 3] Explanation diagram of the relationship between Kt / Ks and the inductance Ld. [Figure 4] FIG. 1 is a diagram illustrating the relationship between Kt / Ks and inductance Lq. [Diagram 5] An explanatory diagram of the relationship between Kt / Ks and iron loss. [Figure 6] An explanatory diagram of the relationship between Kt / Ks and induced voltage. [Figure 7] FIG. 4 is a configuration diagram of an electric motor 100 according to a first modified example. [Figure 8] An explanatory diagram of the relationship between (Kt / Ks) / (W×Br) and iron loss. [Figure 9] FIG. 2 is a graph showing the relationship between L / (W×Br) and the torque constant at room temperature. [Figure 10] FIG. 2 is a graph showing the relationship between L / (W×Br) and the torque constant at high temperatures. [Figure 11] FIG. 11 is a configuration diagram of a compressor 200 according to a fourth embodiment. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0010] Embodiment 1 ***Configuration Description*** The configuration of an electric motor 100 according to the first embodiment will be described with reference to FIG. The electric motor 100 is an embedded magnet type electric motor. The electric motor 100 includes a stator 10 and a rotor 20.

[0011] The stator 10 includes a core back portion 11 and a plurality of teeth portions 12. The core back portion 11 is formed in an annular shape. Each tooth portion 12 is formed extending radially inward from the core back portion 11. Each tooth portion 12 has a wedge-shaped portion 13 at its tip portion that protrudes on both sides in the circumferential direction in a wedge shape that becomes thinner in the radial direction toward the tip. A slot portion 14 is formed between adjacent tooth portions 12. A winding is applied to the slot portion 14. The winding is made of copper or the like. In the first embodiment, the stator 10 includes nine teeth portions 12, and nine slot portions 14 are formed. In the first embodiment, the inside diameter of the stator 10 is 56 mm. In stator 10, the core portion constituting core back portion 11 and each of teeth portions 12 is formed by laminating electromagnetic steel sheets having high magnetic permeability.

[0012] The rotor 20 has permanent magnet insertion holes 21 for embedding permanent magnets 30. In the rotor 20, the iron core portion is formed by laminating electromagnetic steel sheets with high permeability.

[0013] The radial length of the base 15 of the wedge portion 13 is called the base height Kt. The radial length of the circumferential tip 16 of the wedge portion 13 is called the tip height Ks. In Embodiment 1, the base height Kt and the tip height Ks satisfy the relationship of 1 < Kt / Ks ≤ 2.85. In particular, it is desirable that the base height Kt and the tip height Ks satisfy the relationship of 2.33 ≤ Kt / Ks. The reason why it is desirable that the base height Kt and the tip height Ks satisfy the above relationship will be explained. In the following explanation, in Embodiment 1, the residual magnetic flux density Br of the permanent magnet 30, the width W of the permanent magnet 30, the distance L between the tooth portions 12, and the distance D between the stator 10 and the rotor 20 are fixed to the following values. The distance L is the distance between the circumferential tips 16 of the wedge portions 13 for two adjacent tooth portions 12. The distance D is the distance from the inner diameter of the stator to the outer diameter of the rotor. Br = 1.39 T (Tesla), W = 21.25 mm, L = 2.385 mm, D = 0.5 mm. And it will be explained based on the results of measurement by changing the value of Kt / Ks to 2.03, 2.40, 3.63, etc.

[0014] Referring to FIG. 2, the relationship between Kt / Ks and the fundamental wave iron loss will be explained. The fundamental wave iron loss is minimized when Kt / Ks is 3.7. The fundamental wave iron loss increases as Kt / Ks decreases. That is, when Kt / Ks is the minimum value within the range defined in Patent Document 1, the fundamental wave iron loss is minimized. Therefore, when only considering the fundamental wave iron loss, the minimum value within the range of Kt / Ks defined in Patent Document 1, which is the prior art, is appropriate.

[0015] Referring to FIGS. 3 and 4, the relationship between Kt / Ks and the inductances Ld, Lq will be explained. The inductance Ld is the inductance in the d-axis direction. The inductance Lq is the inductance in the q-axis direction. When Kt / Ks decreases, the inductances Ld and Lq increase respectively. In particular, the inductance Lq increases inversely proportionally. When the inductance increases, the harmonic iron loss decreases.

[0016] Referring to FIG. 5, the relationship between Kt / Ks and the iron loss will be described. The iron loss in FIG. 5 is the sum of the fundamental wave iron loss and the harmonic iron loss. The fundamental wave iron loss is minimized when Kt / Ks is 3.7. However, the harmonic iron loss decreases as Kt / Ks decreases. As a result, due to the balance between the fundamental wave iron loss and the harmonic iron loss, the total iron loss is minimized when Kt / Ks is 2.85.

[0017] The rotor 20 has a permanent magnet 30 embedded therein. By effectively utilizing the magnetic force of the permanent magnet 30, it is possible to reduce the copper loss of the motor 100. In order to effectively utilize the magnetic force of the permanent magnet 30, it is necessary to increase the induced voltage. As will be described later, in order to increase the induced voltage, it is necessary to make Kt / Ks smaller than 2.85. Also, it is conceivable to increase the size of the motor 100 and increase the maximum output. In this case, the winding is unwound. That is, the number of turns of the winding decreases. As a result, the inductance decreases and the harmonic iron loss increases. Considering this point, in order to increase the inductance, it is necessary to make Kt / Ks smaller than 2.85. From these considerations, it is desirable to make Kt / Ks 2.85 or less.

[0018] The magnetic flux density on the base 15 side of the wedge portion 13 is higher than that at the circumferential tip 16 of the wedge portion 13. From this, it is desirable to make Kt / Ks greater than 1.

[0019] Therefore, it is desirable that the base height Kt and the tip height Ks satisfy the relationship of 1 < Kt / Ks ≤ 2.85.

[0020] Referring to FIG. 6, the relationship between Kt / Ks and the induced voltage will be described. The induced voltage reaches its maximum when Kt / Ks is 2.33. The induced voltage decreases whether Kt / Ks is greater than or less than 2.33. That is, when Kt / Ks is 2.33, it is possible to most effectively utilize the magnetic force of the permanent magnet 30, and it is possible to reduce the copper loss of the motor 100. Considering this, it is desirable that Kt / Ks is 2.85 or less and in the range of 2.33 or more.

[0021] ***Effect of Embodiment 1*** As described above, in the stator 10 of the motor 100 according to Embodiment 1, the root height Kt and the tip height Ks satisfy the relationship of 1 < Kt / Ks ≤ 2.85. Thereby, the efficiency of the motor 100 can be increased.

[0022] In particular, by satisfying the relationship of 2.33 ≤ Kt / Ks, it is possible to reduce both the iron loss and the copper loss while reducing the iron loss. Thereby, the efficiency of the motor 100 can be increased.

[0023] ***Other Configurations*** <Modification 1> By satisfying the relationship of Kt / Ks described in Embodiment 1, the efficiency of the motor 100 can be increased. Therefore, depending on the required specifications, it may be considered to reduce the noise at the expense of some efficiency. That is, it is considered to allocate the efficiency surplus to noise reduction.

[0024] As shown in FIG. 7, the rotor 20 may have a gap 22 formed in the iron core portion between the permanent magnet insertion hole 21 and the outer diameter of the rotor 20. By forming the gap 22, the magnetic attraction force by which the stator 10 attracts the rotor 20 can be suppressed. As a result, the noise can be reduced. Forming the air gap 22 increases magnetic saturation in the iron core of the rotor 20. This causes more magnetic flux to flow through the leakage path, reducing the effective value of the induced voltage. For this reason, when forming the air gap 22, it is necessary to accept a decrease in efficiency or an increase in cost due to an increase in the core width. However, by satisfying the relationship Kt / Ks described in the first embodiment, it is possible to increase the efficiency of the electric motor 100 without an increase in cost. Therefore, by forming the air gap 22, it is possible to allocate the surplus efficiency to noise reduction.

[0025] <Variation 2> It is also possible to reduce direct material costs by sacrificing some efficiency. In other words, it is possible to allocate the efficiency surplus to reducing direct material costs. The winding material may be aluminum rather than copper, which reduces efficiency but costs.

[0026] <Modification 3> As shown in Figs. 3 and 4, the change in inductances Ld and Lq when Kt / Ks is reduced is more significant when a rare earth magnet is used than when a ferrite magnet is used. Rare earth magnets have a higher residual magnetic flux density than ferrite magnets. Therefore, magnetic saturation at base 15 is more severe when rare earth magnets are used than when ferrite magnets are used. As a result, the changes in inductances Ld and Lq are greater when rare earth magnets are used than when ferrite magnets are used.

[0027] Therefore, it may be possible to use a rare earth magnet as the permanent magnet 30. Ferrite magnets have traditionally been widely used in small electric motors. Ferrite magnets are less expensive than rare earth magnets. For this reason, electric motors that use conventional technology with a large Kt / Ks ratio, which is compatible with ferrite magnets, have become widespread. However, the performance of rare earth magnets has improved recently. This makes it possible to manufacture a compact electric motor by using rare earth magnets and packing more magnetic flux per plane. Furthermore, the total direct material cost of this motor, including the iron core, magnets, and windings, is less expensive than an electric motor using ferrite magnets. Here, the increase in magnetic flux density per plane causes an increase in iron loss. However, by satisfying the Kt / Ks relationship described in the first embodiment, the increase in iron loss can be suppressed. This increases the effectiveness of using rare earth magnets as the permanent magnets 30.

[0028] <Variation 4> The core portions of the stator 10 and rotor 20 are pressed products formed by laminating electromagnetic steel sheets. In the pressing process, the rotor 20 portion is punched out from a single electromagnetic steel sheet, and then the stator 10 portion is punched out. For this reason, a certain amount of clearance is necessary between the stator 10 and the rotor 20. The clearance is the distance D from the inner diameter of the stator to the outer diameter of the rotor (see FIG. 1). To ensure processing precision, it is desirable for the clearance D to be equal to or greater than the thickness t of the electromagnetic steel sheet. The smaller the distance D, the more effectively the magnetic flux of the permanent magnet can be taken into the stator 10. The magnet size can be made smaller accordingly. However, if the distance D is small, the iron loss increases. For this reason, it has not been possible to effectively utilize all of the increased magnetic flux up to now. However, by satisfying the relationship Kt / Ks described in the first embodiment, the increase in iron loss can be suppressed. This allows the increased magnetic flux to be effectively utilized, so it is desirable to select D=t which maximizes the magnetic flux.

[0029] <Variation 5> In the first embodiment, the rotor 20 has permanent magnet insertion holes 21, and the permanent magnets 30 are embedded in the permanent magnet insertion holes 21. That is, the electric motor 100 is an IPM motor. IPM stands for Interior Permanent Magnet. However, the electric motor 100 may be an SPM motor in which the permanent magnets 30 are attached to the surface of the rotor 20. SPM stands for Surface Permanent Magnet. However, for the following reasons, it is preferable that the electric motor 100 is an IPM motor. The electric motor 100 has reduced iron loss and can suppress the effect of magnetic saturation on the motor efficiency. Therefore, the electric motor 100 can make full use of rare earth magnets, which have a stronger effect on magnetic saturation than ferrite magnets. When using rare earth magnets, the unit price of the magnet material is high, so it is preferable that the magnet shape is rectangular, which has good material yield in production. In an IPM motor, rectangular magnets can be used. Therefore, it is well suited to the electric motor 100 according to the first embodiment.

[0030] Embodiment 2 The second embodiment differs from the first embodiment in that the range of Kt / Ks is determined taking into consideration the width W and residual magnetic flux density Br of the permanent magnet 30. In the second embodiment, this difference will be described, and the description of the same points will be omitted.

[0031] It is conceivable to increase the size of the electric motor 100, and therefore the width W of the permanent magnet 30 will become wider. It is also conceivable to use a permanent magnet 30 with higher magnetic force. As a result, it is conceivable that the magnetic force of the permanent magnet 30 will increase. When the magnetic force of the permanent magnet 30 increases, the value of Kt / Ks at which the total iron loss becomes minimum changes. Assume that the angle θ (see FIG. 1) between the straight line portion of the teeth 12 extending radially inward and the wedge-shaped portion 13 extending circumferentially is constant. In this case, the value of Kt / Ks must be reduced to reduce magnetic saturation at the root height Kt that accompanies an increase in magnetic force. In other words, the value of Kt / Ks that minimizes the total iron loss is smaller than 2.85. The amount of magnetic flux of the permanent magnet 30 can be expressed as the product of the width W of the permanent magnet 30 and the residual magnetic flux density Br of the permanent magnet 30. In other words, the magnetic force of the permanent magnet 30 is expressed by W×Br.

[0032] The relationship between (Kt / Ks) / (W×Br) and iron loss will be described with reference to Fig. 8. The iron loss in Fig. 8 is the sum of fundamental iron loss and harmonic iron loss. Iron loss is minimum when (Kt / Ks) / (W×Br) is 0.0965. Iron loss increases whether (Kt / Ks) / (W×Br) is large or small. As explained in the first embodiment, taking into consideration the possibility of increasing the induced voltage and increasing the size of the motor 100, it is desirable for (Kt / Ks) / (W×Br) to be 0.0965 or less.

[0033] ***Effects of the second embodiment*** As described above, in the stator 10 of the electric motor 100 according to the second embodiment, the root height Kt and the tip height Ks satisfy the relationship (Kt / Ks) / (W×Br)≦0.0965 with respect to the width W of the permanent magnet 30 and the residual magnetic flux density Br of the permanent magnet 30. As a result, the efficiency of the electric motor 100 can be increased even when the width W of the permanent magnet 30 is widened or when a permanent magnet 30 with high magnetic force is used.

[0034] Embodiment 3 The third embodiment differs from the first and second embodiments in that it defines the range of the distance L between two adjacent teeth portions 12. In the third embodiment, this difference will be described, and a description of the same points will be omitted.

[0035] The appropriate distance L (see FIG. 1) between the circumferential tips 16 of the wedge-shaped portions 13 of two adjacent teeth portions 12 varies depending on the magnetic force of the permanent magnets 30. The torque constant decreases due to leakage flux between the adjacent teeth portions 12. Therefore, in order to consider the appropriate distance L, it is appropriate to track the change in the torque constant.

[0036] The relationship between L / (W×Br) and the torque constant will be described with reference to FIG. 9 and FIG. FIG. 9 shows the relationship between L / (W×Br) and the torque constant at normal temperature. As shown in FIG. 9, at normal temperature, as L / (W×Br) increases, the torque constant increases. The torque constant is approximately maximized when L / (W×Br) is 0.08. Note that with L / (W×Br) = 0.06 as the boundary, the slope of the increase in the torque constant with the increase in L / (W×Br) becomes gentle. FIG. 10 shows the relationship between L / (W×Br) and the torque constant at high temperature. As shown in FIG. 10, at high temperature, the point at which the torque constant is approximately maximized when L / (W×Br) is 0.08 is the same as that at normal temperature. However, when L / (W×Br) is greater than 0.08, the torque constant decreases. Note that with L / (W×Br) = 0.1 as the boundary, the slope of the increase in the torque constant with the increase in L / (W×Br) becomes steep.

[0037] Based on the above, if L / (W×Br) is in the range greater than 0.06 and less than 0.1, there is no significant change in the torque constant. Therefore, it is desirable that the distance L satisfies the relationship 0.06 < L / (W×Br) < 0.1 with respect to the width W of the permanent magnet 30 and the residual magnetic flux density Br of the permanent magnet 30.

[0038] ***Effects of Embodiment 3*** As described above, in the stator 10 of the motor 100 according to Embodiment 3, the distance L satisfies the relationship 0.06 < L / (W×Br) < 0.1 with respect to the width W of the permanent magnet 30 and the residual magnetic flux density Br of the permanent magnet 30. Thereby, the efficiency of the motor 100 can be increased.

[0039] Embodiment 4. Embodiment 4 is different from Embodiments 1 to 3 in that the motor 100 is mounted on the compressor 200. In Embodiment 4, this difference will be described, and the description of the same points will be omitted. In Embodiment 4, a rotary compressor will be used as the compressor 200 for explanation.

[0040] ***Description of the Configuration*** The configuration of a compressor 200 according to the fourth embodiment will be described with reference to FIG. The compressor 200 includes a shell 210, a compression mechanism 220 disposed in the shell 210, and an electric motor 100 that drives the compression mechanism 220. The electric motor 100 is the one described in the first to third embodiments. The compressor 200 further includes a shaft 230 (crankshaft) that connects the electric motor 100 and the compression mechanism 220 so as to be capable of transmitting power. The shaft 230 fits into a shaft hole 23 (see FIG. 1) of the rotor 20 of the electric motor 100.

[0041] The shell 210 is a sealed container formed of, for example, a steel plate. The shell 210 covers the electric motor 100 and the compression mechanism 220. The shell 210 has an upper shell 211 and a lower shell 212. The upper shell 211 is provided with an airtight terminal 213 (glass terminal) as a terminal portion for supplying electric power to the electric motor 100 from outside the compressor 200, and a discharge pipe 214 for discharging the refrigerant compressed in the compressor 200 to the outside. The airtight terminal is embedded in a wall surface of the sealed container. The lower shell 212 houses the electric motor 100 and the compression mechanism 220.

[0042] The compression mechanism 220 has an annular first cylinder 221 and an annular second cylinder 222 along the shaft 230. The first cylinder 221 and the second cylinder 222 are fixed to an inner periphery of the shell 210 (lower shell 212). An annular first piston 223 is disposed on the inner periphery of the first cylinder 221. An annular second piston 224 is disposed on the inner periphery of the second cylinder 222. The first piston 223 and the second piston 224 are rotary pistons that rotate together with the shaft 230.

[0043] A partition plate 225 is provided between the first cylinder 221 and the second cylinder 222. The partition plate 225 is a disk-shaped member having a through hole in the center. The cylinder chambers of the first cylinder 221 and the second cylinder 222 are provided with vanes (not shown) that divide the cylinder chambers into a suction side and a compression side. The first cylinder 221, the second cylinder 222, and the partition plate 225 are fixed together by bolts.

[0044] An upper frame 226 is disposed above the first cylinder 221 so as to close the upper side of the cylinder chamber of the first cylinder 221. A lower frame 227 is disposed below the second cylinder 222 so as to close the lower side of the cylinder chamber of the second cylinder 222. The upper frame 226 and the lower frame 227 support a shaft 230 rotatably.

[0045] Refrigeration oil (not shown) for lubricating each sliding part of compression mechanism 220 is stored in the bottom of lower shell 212 of shell 210. The refrigeration oil rises in a hole formed in the axial direction inside shaft 230, and is supplied to each sliding part from oil supply holes formed in multiple places on shaft 230.

[0046] The stator 10 of the electric motor 100 is attached to the inside of the shell 210 by shrink fitting. Electric power is supplied to the windings of the stator 10 from an airtight terminal 213 attached to the upper shell 211.

[0047] An accumulator 240 that stores refrigerant gas is attached to the shell 210. The accumulator 240 is held, for example, by a holder provided on the outside of the lower shell 212. A pair of suction pipes are attached to the shell 210, and the refrigerant gas is supplied from the accumulator 240 to the cylinder via the suction pipes.

[0048] As the refrigerant, for example, R410A, R407C, R22, etc. may be used. However, from the viewpoint of preventing global warming, it is desirable to use a refrigerant with a low GWP (global warming potential). As the refrigerant with a low GWP, for example, the following refrigerants can be used. (1) Halogenated hydrocarbons that have carbon double bonds in their composition can be used. For example, 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 may be used. For example, R1270 (propylene) may 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) 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 may be used. 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, it is practically desirable to use a mixture of HFO-1234yf and R32 or R41, which are refrigerants with a higher pressure than HFO-1234yf.

[0049] The basic operation of compressor 200 is as follows. The refrigerant gas supplied from the accumulator 240 is supplied to each cylinder chamber of the first cylinder 221 and the second cylinder 222 through a suction pipe. When the electric motor 100 is driven and the rotor 20 rotates, the shaft 230 rotates together with the rotor 20. Then, the first piston 223 and the second piston 224 fitted to the shaft 230 rotate eccentrically in each cylinder chamber, compressing the refrigerant in each cylinder chamber. The compressed refrigerant passes through a hole (not shown) provided in the rotor 20 of the electric motor 100, rises in the shell 210, and is discharged to the outside from a discharge pipe.

[0050] The compressor 200 is used in a refrigeration cycle of an air conditioner, etc. This constitutes a refrigeration and air conditioning system.

[0051] ***Effects of the Fourth Embodiment*** As described above, the compressor 200 according to the fourth embodiment is configured using the electric motor 100 according to the first to third embodiments. More than half of the direct material cost of the compressor 200 is accounted for by the electric motor 100. By using the electric motor 100 according to the first to third embodiments for the compressor 200, it is possible to increase the degree of freedom in design. Furthermore, it is possible to configure the compressor 200 specialized for high efficiency or low cost.

[0052] Furthermore, by configuring a refrigeration and air conditioning system using the compressor 200, it is possible to configure a refrigeration and air conditioning system that is specialized for high efficiency or low cost.

[0053] The above describes the embodiments and modifications of the present disclosure. Some of these embodiments and modifications may be combined and implemented. Also, one or some of them may be partially implemented. Note that the present disclosure is not limited to the above embodiments and modifications, and various modifications are possible as necessary. [Explanation of symbols]

[0054] 100 electric motor, 10 stator, 11 core back portion, 12 teeth portion, 13 wedge portion, 14 slot portion, 15 root, 16 circumferential tip, 20 rotor, 21 permanent magnet insertion hole, 22 gap, 23 shaft hole, 30 permanent magnet, 200 compressor, 210 shell, 211 upper shell, 212 lower shell, 213 airtight terminal, 214 discharge pipe, 220 compression mechanism, 221 first cylinder, 222 second cylinder, 223 first piston, 224 second piston, 225 partition plate, 226 upper frame, 227 lower frame, 230 shaft, 240 accumulator.

Claims

1. An annular core back portion; a plurality of teeth extending radially inward from the core back portion, the teeth having a wedge-shaped portion protruding on both sides in the circumferential direction in a wedge shape that becomes thinner toward a tip; Equipped with The teeth portion of the stator of an electric motor has a root height Kt, which is the radial length of the root of the wedge-shaped portion, and a tip height Ks, which is the radial length of the tip of the wedge-shaped portion, which satisfy the relationship 1 < Kt / Ks ≦ 2.

85.

2. The base height Kt and the tip height Ks satisfy the relationship 2.33≦Kt / Ks.

2. The stator of an electric motor according to claim 1.

3. The electric motor has a permanent magnet embedded in a rotor, The root height Kt and the tip height Ks satisfy the relationship (Kt / Ks) / (W×Br)≦0.0965 with respect to the width W of the permanent magnet and the residual magnetic flux density Br of the permanent magnet.

2. The stator of an electric motor according to claim 1.

4. The electric motor has a permanent magnet embedded in a rotor, A distance L between the tips of the wedge-shaped portions of two adjacent teeth among the plurality of teeth satisfies the relationship of 0.06<L / (W×Br)<0.1 with respect to a width W of the permanent magnet and a residual magnetic flux density Br of the permanent magnet. The stator of an electric motor according to any one of claims 1 to 3.

5. The electric motor has a permanent magnet embedded in a rotor, In the rotor, a gap is provided between the permanent magnet and the outer diameter of the rotor.

5. A stator for an electric motor according to claim 1.

6. A slot portion is formed between the plurality of teeth portions, The slots are wound with aluminum.

6. A stator for an electric motor according to any one of claims 1 to 5.

7. The motor has a rare earth permanent magnet embedded in the rotor.

7. A stator for an electric motor according to any one of claims 1 to 6.

8. an iron core portion forming the core back portion and the teeth portion of the stator is formed by laminating steel plates, The thickness t of the steel plate is equal to the distance D from the inner diameter of the stator to the outer diameter of the rotor.

8. A stator for an electric motor according to any one of claims 1 to 7.

9. The electric motor has a rotor formed with a permanent magnet insertion hole for embedding a permanent magnet, A permanent magnet is embedded in the permanent magnet insertion hole.

9. A stator for an electric motor according to any one of claims 1 to 8.

10. A compressor equipped with the stator of the electric motor according to any one of claims 1 to 9.

11. A refrigeration and air conditioning device equipped with the compressor according to claim 10.

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