Permanent magnet synchronous motors, compressors, and devices

Abstract

In this permanent magnet synchronous motor 3 of the present invention, a stator 3b has an annular stator yoke 31 centered on a rotational axis 8, a plurality of stator teeth 32 extending from the stator yoke 31 toward a rotor 3a, and slots 40 formed between the stator teeth 32, wherein windings 50 are disposed in the slots 40 and the stator teeth 32 each have: a stator tooth base 32a around which the winding 50 is wound; and a stator tooth end portion 32b forming, at the end of the stator tooth base 32a, a facing surface 35 facing the rotor 3a. At least two small holes 70a, 70b are arranged side by side in a direction along the facing surface 35 in the stator tooth end portion 32b, thereby being able to reduce force variation in the tooth direction (radial direction) and obtain low noise due to low vibration and high efficiency.

Description

[Technical field]

[0001] The present invention relates to a permanent magnet synchronous motor, a compressor using this permanent magnet synchronous motor, and an apparatus using this compressor. [Background technology]

[0002] Patent Document 1 discloses a rotating electric machine that can suppress a decrease in the circumferential torque that should be generated by the rotating electric machine and reduce the radial electromagnetic excitation force generated in the rotating electric machine. In Patent Document 1, a decrease in circumferential torque is suppressed by providing an axial communication hole in the vicinity of the air gap in the teeth portion. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] JP 2015-96022 A Summary of the Invention [Problem to be solved by the invention]

[0004] It was found that the electromagnetic excitation force acting on the stator teeth changes depending on the rotor's rotational position and the current passing through it, and that the radial force that strengthens the electromagnetic excitation force is greatest on the counter-rotation side from the center of the teeth. However, it is important to adjust the flow of magnetic flux while not reducing torque.

[0005] An object of the present invention is to provide a permanent magnet synchronous motor that can reduce fluctuations in radial force and achieve low noise due to low vibration and high efficiency, a compressor that uses this permanent magnet synchronous motor and is used in air conditioners, dehumidifiers, heat pump water heaters, refrigerators (home refrigerators, commercial refrigerators), ice makers, showcases, heat pump washer-dryers, vending machines, etc., and equipment that uses this compressor. [Means for solving the problem]

[0006] The permanent magnet synchronous motor of the present invention described in claim 1 has a rotor that is rotatably arranged around a rotation axis, and a stator that is arranged with an air gap between the rotor, the stator has an annular stator yoke that is centered around the rotation axis, a plurality of stator teeth that extend from the stator yoke towards the rotor, and slots that are formed between the stator teeth, and a winding is arranged in the slot. The stator teeth have a stator teeth base portion around which the winding is wound, and a stator teeth tip portion that is a tip of the stator teeth base and forms a surface facing the rotor, and the stator teeth tip portion has at least two small holes. A group of small holes is arranged, the cross-sectional shape of each small hole is a circle having the same diameter, the dimension between the small hole and the opposing surface is smaller than the diameter of the small hole, and the distance from each small hole to the opposing surface is constant, thereby are arranged in a direction along the opposing surfaces. The small hole group is disposed in a section where the fluctuation range of the tooth direction force acting on the tip portion of the stator tooth becomes small. It is characterized by: The present invention as set forth in claim 2 provides the permanent magnet synchronous motor as set forth in claim 1, wherein the center of the width dimension of the stator tooth base in the circumferential direction is set as a virtual center line of the tooth base, and the small holes are arranged on the stator tooth base. The above The small holes are arranged so that the virtual center of the small hole group is in the counter-rotation direction of the rotor from the virtual center line of the teeth base. The present invention as set forth in claim 3 is characterized in that in the permanent magnet synchronous motor as set forth in claim 1 or 2, the number of the small holes is three or more. Claim 4 The invention as described herein comprises claims 1 to Claim 3 In the permanent magnet synchronous motor described in any one of claims 1 to 5, the stator is configured by stacking a plurality of stator cores in the axial direction of the rotating shaft, and some of the stator cores have the small holes formed therein, while other stator cores do not have the small holes formed therein. Claim 5 The compressor of the present invention described is Claim 4 The permanent magnet synchronous motor described in the above is used, the permanent magnet synchronous motor and a compression mechanism are connected by a shaft, the stator core that does not form the small hole is arranged on the compression mechanism side, and the stator core that forms the small hole is arranged on the side away from the compression mechanism. Claim 6 The compressor of the present invention as described in claim 1 to Claim 4The present invention is characterized in that the permanent magnet synchronous motor according to any one of claims 1 to 5 is used, the permanent magnet synchronous motor and a compression mechanism are connected by a shaft, and the refrigerant is compressed by the compression mechanism. Claim 7 The device of the present invention described is Claim 5 or Claim 6 The compressor, the condenser, the pressure reducing device, and the evaporator described in the above are connected in a ring shape by piping. Effect of the Invention

[0007] According to the present invention, the flow of magnetic flux can be adjusted, and the fluctuation in radial force can be reduced while maintaining the same torque as when no small holes are provided, thereby achieving low noise due to low vibration and high efficiency. [Brief description of the drawings]

[0008] [Figure 1] FIG. 1 is a vertical cross-sectional view showing the configuration of a compressor using a permanent magnet synchronous motor according to an embodiment of the present invention; [Diagram 2] A configuration diagram of a permanent magnet synchronous motor according to the present embodiment. [Diagram 3] FIG. 1 is a diagram showing the configuration of a main part of a stator core of a permanent magnet synchronous motor according to an embodiment of the present invention; [Figure 4] Graph showing tooth direction (radial direction) force and torque according to this embodiment [Diagram 5] A graph showing the relationship between torque and the variation range of the force in the teeth direction (radial direction) relative to the arrangement angle of the small holes [Figure 6] FIG. 1 is a schematic diagram showing a stator core of a permanent magnet synchronous motor according to another embodiment of the present invention; [Figure 7] FIG. 1 is a schematic diagram showing a stator core of a permanent magnet synchronous motor according to another embodiment of the present invention; [Figure 8] FIG. 13 is a block diagram showing a main part of a compressor using a permanent magnet synchronous motor according to another embodiment of the present invention. [Figure 9] A graph showing the tooth direction (radial direction) force and torque according to the embodiment shown in FIG. [Figure 10]FIG. 11 is a block diagram showing a main part of a compressor using a permanent magnet synchronous motor according to still another embodiment of the present invention. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0009] The permanent magnet synchronous motor according to the first embodiment of the present invention has at least two small holes at the tips of the stator teeth. A group of small holes is arranged, the cross-sectional shape of each small hole is a circle having the same diameter, the dimension between the small hole and the opposing surface is smaller than the diameter of the small hole, and the distance from each small hole to the opposing surface is constant, so that each small hole are arranged in a direction along the opposing surfaces. The small hole group is arranged in a section where the fluctuation range of the tooth direction force acting on the tip of the stator teeth becomes small. According to this embodiment, the flow of magnetic flux can be adjusted, and while maintaining the same torque as in the case where no small holes are provided, the fluctuation in the force in the teeth direction (radial direction) can be reduced, and low noise due to low vibration and high efficiency can be achieved.

[0010] In the second embodiment of the present invention, in the permanent magnet synchronous motor according to the first embodiment, the center of the circumferential width dimension of the stator tooth base is set to the tooth base imaginary center line, and the small holes are arranged so that the imaginary center of a group of small holes is in the counter-rotation direction of the rotor from the tooth base imaginary center line. According to this embodiment, in particular, the small hole group can be arranged at an angle where the tooth direction (radial direction) force is locally high, and it is possible to simultaneously reduce the fluctuation of the tooth direction (radial direction) force and suppress a decrease in torque.

[0011] The third embodiment of the present invention is a permanent magnet synchronous motor according to the first or second embodiment, in which the number of small holes is three or more. According to this embodiment, it is easy to adjust the flow of magnetic flux, and while maintaining the same torque as when no small holes are provided, it is possible to reduce the fluctuation in the force in the teeth direction (radial direction), thereby achieving low noise due to low vibration and high efficiency.

[0012] The present invention Fourth The embodiment of the present invention is as follows: ThirdIn the permanent magnet synchronous motor according to any one of the above embodiments, the stator is configured by stacking a plurality of stator cores in the axial direction of the rotating shaft, with small holes formed in some of the stator cores and small holes not formed in other stator cores. According to this embodiment, since the torque pulsation phase is shifted between the stator cores without small holes and the stator cores with small holes, the torque pulsation can be reduced by stacking these stator cores.

[0013] The present invention Fifth The compressor according to the embodiment of the present invention comprises: Fourth The permanent magnet synchronous motor according to the embodiment is used, the permanent magnet synchronous motor and the compression mechanism are connected by a shaft, and a stator core without small holes is arranged on the compression mechanism side, and a stator core with small holes is arranged on the side away from the compression mechanism. According to this embodiment, by arranging a stator core with small fluctuations in the tooth direction (radial direction) force on the side away from the compression mechanism, the support rigidity of the rotor is increased.

[0014] The present invention Sixth The compressor according to the embodiment includes first to fourth Fourth The permanent magnet synchronous motor according to any one of the above embodiments is used, the permanent magnet synchronous motor and a compression mechanism are connected by a shaft, and the refrigerant is compressed by the compression mechanism. According to this embodiment, it is possible to realize a compressor with low noise due to low vibration and high efficiency without reducing torque.

[0015] The present invention Seventh The device according to the embodiment of the present invention comprises: Fifth or Sixth The compressor, the condenser, the pressure reducing device, and the evaporator according to the embodiment are connected in a ring shape by piping. According to this embodiment, it is possible to realize a highly efficient device with low noise due to low vibration without reducing torque. EXAMPLES

[0016] An embodiment of the present invention will now be described with reference to the drawings. FIG. 1 is a vertical sectional view showing the configuration of a compressor using a permanent magnet synchronous motor according to this embodiment. The compressor 10 according to this embodiment includes, in a sealed container 1, a compression mechanism 2 for compressing refrigerant gas, and a permanent magnet synchronous motor 3 for driving the compression mechanism 2. The inside of the sealed container 1 is divided into one container space and the other container space by the compression mechanism part 2. A permanent magnet synchronous motor 3 is disposed in the other container space. The space inside the other container is divided into a compression mechanism side space and an oil-storage side space by the permanent magnet synchronous motor 3. An oil storage section 4 is disposed in the oil-storage side space. A suction pipe 5 and a discharge pipe 6 are fixed to the sealed container 1 by welding. The suction pipe 5 and the discharge pipe 6 lead to the outside of the sealed container 1 and are connected to members that constitute a refrigeration cycle. The suction pipe 5 introduces refrigerant gas from the outside of the sealed container 1, and the discharge pipe 6 discharges the refrigerant gas from one of the container spaces to the outside of the sealed container 1.

[0017] The main bearing member 7a is fixed inside the sealed container 1 by welding, shrink fitting, or the like, and supports a shaft 8 (the rotating shaft of the rotor 3a). One end of the shaft 8 is supported by the main bearing member 7a, and the other end is supported by a bearing 7b. The fixed scroll 2a is bolted to this main bearing member 7a. The orbiting scroll 2b that meshes with the fixed scroll 2a is sandwiched between the main bearing member 7a and the fixed scroll 2a. The fixed scroll 2a and the orbiting scroll 2b constitute a scroll-type compression mechanism 2. Between the orbiting scroll 2b and the main bearing member 7a, a rotation restraint mechanism 9 such as an Oldham ring is provided. The rotation restraint mechanism 9 prevents the orbiting scroll 2b from rotating on its axis and guides the orbiting scroll 2b to move in a circular orbit. The orbiting scroll 2b is eccentrically driven by an eccentric shaft portion 8a provided at the upper end of the shaft 8. Due to this eccentric drive, the compression chamber formed between the fixed scroll 2a and the orbiting scroll 2b moves from the outer periphery toward the center of the compression mechanism portion 2, reducing the volume and performing compression.

[0018] The permanent magnet synchronous motor 3 has a rotor 3a arranged to be rotatable about a rotating shaft 8, and a stator 3b arranged with an air gap between the rotor 3a and the stator 3b.

[0019] The refrigerant is sucked into the compression mechanism 2 through the suction pipe 5, and is compressed in the compression mechanism 2. Thereafter, the refrigerant is discharged from the discharge pipe 6. In the device according to this embodiment, the compressor 10, the condenser 61, the pressure reducing device 62, and the evaporator 63 are connected in a ring shape by piping. The condenser 61 condenses the refrigerant discharged from the discharge pipe 6, the pressure reducing device 62 reduces the pressure of the refrigerant condensed in the condenser 61, and the evaporator 63 evaporates the refrigerant reduced in pressure by the pressure reducing device 62. The refrigerant evaporated in the evaporator 63 is returned to the compressor 10 through the suction pipe 5 .

[0020] 2A and 2B are diagrams showing the configuration of a permanent magnet synchronous motor according to this embodiment, with FIG. 2(a) being a cross-sectional view showing the motor mounted on the compressor shown in FIG. 1, FIG. 2(b) being a cross-sectional view showing the motor from FIG. 2(a) with the shaft and rotor removed, and FIG. 2(c) being a cross-sectional view showing the motor from FIG. 2(a) with the sealed container and windings removed. The rotor 3a is fixed to the shaft 8, and the stator 3b is fixed to the sealed container 1. In the compressor 10 according to this embodiment, the shaft 8 serves as the rotation axis of the rotor 3a. The rotor 3a is made of a magnetic material, and a plurality of slits are provided inside the rotor 3a, and a permanent magnet 11 is disposed in each of these slits. The stator 3b is configured by stacking a plurality of stator cores 30 in the axial direction of the rotating shaft 8 of the rotor 3a. The stator core 30 has an annular stator yoke 31 centered on the rotating shaft 8 of the rotor 3a, a plurality of stator teeth 32 extending from the stator yoke 31 toward the rotor 3a, and slots 40 formed between the stator teeth 32. A winding 50 is arranged in the slots 40.

[0021] FIG. 3 is a configuration diagram showing a main part of a stator core of a permanent magnet synchronous motor according to this embodiment. The stator teeth 32 of the stator core 30 in this embodiment have a stator teeth base 32a around which a winding 50 (see Figure 2) is wound via an insulating material (not shown), and a stator teeth tip 32b that forms an opposing surface 35 with the rotor 3a (see Figure 2) at the tip of the stator teeth base 32a. Stator tooth tip portions 32b are formed to protrude on both sides beyond the circumferential width dimension t of stator tooth base portions 32a. At least two small holes 70a, 70b are arranged in the tip portion 32b of the stator teeth in a direction along the opposing surface 35. Here, the small holes 70a, 70b are intended to increase the magnetic resistance, and are highly effective if they are non-magnetic, and may be voids filled with resin. By arranging these small holes 70a, 70b, the flow of magnetic flux can be adjusted, and while maintaining the same torque as when no small holes are provided, fluctuations in force in the teeth direction (radial direction) can be reduced, resulting in low noise due to low vibration and high efficiency.

[0022] If the center of the circumferential width dimension t of the stator tooth base 32a is the tooth base virtual center line A, the multiple small holes 70a, 70b are arranged so that the virtual center 70x of the small hole group 70 consisting of multiple small holes 70a, 70b is in the counter-rotation direction of the rotor 3a from the tooth base virtual center line A. In this manner, by arranging multiple small holes 70a, 70b, the small hole group 70 can be arranged at an angle where the tooth-direction (radial) force is locally high, thereby achieving both a reduction in fluctuations in the tooth-direction (radial) force and suppression of torque reduction. For example, in a 6-pole, 9-teeth permanent magnet synchronous motor 3, it is preferable to arrange multiple small holes 70a, 70b so that the virtual center 70x is shifted by about 2° to 3° from the tooth base virtual center line A in the counter-rotation direction of the rotor 3a. In addition, if the diameter of small hole 70a is 70at and the diameter of small hole 70b is 70bt, it is preferable that diameters 70at and 70bt are 1 mm or more, diameter 70at + diameter 70bt ≦ width dimension t / 2, the distance between small holes 70a and 70b is 0.5 mm or more, the distance between small hole 70a and the opposing surface 35 is 0.5 mm or more, and the distance between small hole 70b and the opposing surface 35 is 0.5 mm or more.

[0023] FIG. 4 is a graph showing the teeth direction (radial direction) force and torque according to this embodiment. 4(a) shows the relationship between the tooth direction (radial direction) force acting on one stator tooth tip 32b and the rotation angle of the rotor 3a. In the conventional example, no small holes are provided. As the rotor 3a rotates, the stator teeth tip 32b receives a teeth-direction (radial) force with a periodic component according to the number of rotor magnetic poles. This embodiment is a six-pole motor, and the teeth-direction (radial) force acting on one stator tooth tip is a teeth-direction (radial) force with one periodic component at a rotation angle of 60°. In this embodiment, the motor is three-phase, and the fluctuation in the force acting on the stator teeth tips 32b is out of phase with respect to the teeth direction (radial direction) by 120° in electrical angle and 40° in rotation angle. A large fluctuation range of the force in the tooth direction (radial direction) causes large vibrations in the stator teeth 32 and therefore large vibrations in the motor, which is a factor in large vibrations in general rotary compressors and scroll compressors in which the outer periphery of the stator 3b is fixed in contact with the outer wall of the compressor 10. By reducing the fluctuation range of the force in the teeth direction (radial direction), a motor and compressor 10 with low vibrations can be achieved. The tooth direction (radial direction) force does not act uniformly on the stator tooth tips 32b, but rather the locations at which it acts locally change with the rotation of the rotor 3a. According to this embodiment, as shown in Fig. 4(a), it is possible to effectively reduce the tooth direction (radial direction) force acting locally as the rotor 3a rotates. The tooth direction (radial direction) fluctuating force ratio is 86% compared to the conventional example.

[0024] On the other hand, as shown in FIG. 4(b), when comparing the torque of the conventional example with the torque of this embodiment, it is found that the maximum and minimum torque values ​​of this embodiment increase, but the average torque is equivalent to that of the conventional motor.

[0025] Fig. 5 is a graph showing the relationship between torque and the fluctuation range of the force in the tooth direction (radial direction) relative to the arrangement angle of the small holes. In Fig. 5, the arrangement of the two small holes 70a, 70b shown in this embodiment is changed. The arrangement angle of the small holes on the imaginary center line A of the stator teeth base is set to 0°, and the rotation direction side is set to a negative angle, anti The rotation direction side is indicated by a positive angle. 5, changing the arrangement angle of the small holes 70a, 70b changes the fluctuation range of the force in the teeth direction (radial direction) and the torque. Here, reducing the fluctuation range of the force in the teeth direction (radial direction) is effective in reducing vibration. The fluctuation range of the force in the tooth direction (radial direction) is reduced by arranging the two small holes 70a, 70b in section A (approximately -5° to 9°) shown in Fig. 5. In particular, the effect of reducing the fluctuation range of the force in the tooth direction (radial direction) is large when the small holes 70a, 70b are arranged at about 3° in the counter-rotation direction. On the other hand, the torque is equivalent to that of -3° to 7° without small holes. Therefore, by arranging the small holes 70a, 70b at an angle of about 3° in the counter-rotation direction from the imaginary center line A of the tooth base, it is possible to achieve both low vibration and high torque.

[0026] 6 and 7 are diagrams showing the main configuration of a stator core of a permanent magnet synchronous motor according to another embodiment. Note that the configuration other than the small holes is the same as that of the above embodiment, so a description thereof will be omitted. The stator teeth tip portion 32b of the stator core 30 shown in FIG. 6(a) is provided with three small holes 70a, 70b, and 70c. In this way, the number of small holes 70a, 70b, and 70c can be three or more. By providing three or more small holes 70a, 70b, and 70c, the flow of magnetic flux can be easily adjusted, and the same torque as when the small holes 70a, 70b, and 70c are not provided can be maintained while the fluctuation in the force in the teeth direction (radial direction) can be reduced, resulting in low noise due to low vibration and high efficiency. Small holes 71a, 71b having a rectangular cross-sectional shape are provided in the tip portion 32b of the stator teeth of the stator core 30 shown in Fig. 6(b). Although Fig. 6(a) shows the case where two small holes 71a, 71b are provided, three or more small holes may be provided. Small holes 72a, 72b having a triangular cross-sectional shape are provided in the tip portion 32b of the stator teeth of the stator core 30 shown in Fig. 6(c), with the straight portion of the triangle facing the opposing surface 35. Fig. 6(c) shows the case where two small holes 72a, 72b are provided, but three or more small holes may be provided. Small holes 72a, 72b having a triangular cross-sectional shape are provided in the tip portion 32b of the stator teeth of the stator core 30 shown in Fig. 6(d), with the apex of the triangle facing the opposing surface 35. Fig. 6(d) shows the case where two small holes 72a, 72b are provided, but three or more small holes may be provided. Small holes 72a, 72b with a triangular cross-sectional shape are provided in the tip portion 32b of the stator tooth of the stator core 30 shown in Fig. 6(e), with the straight line portion of the small hole 72a facing the opposing surface 35, and the apex portion of the small hole 72b facing the opposing surface 35. Fig. 6(e) shows the case where two small holes 72a, 72b are provided, but three or more small holes may be provided. Note that Figure 6(b) shows small holes 71a, 71b with a rectangular cross-sectional shape, and Figures 6(c) to 6(e) show small holes 72a, 72b with a triangular cross-sectional shape, but the cross-sectional shape may be another polygonal shape.

[0027] Small holes 73a, 73b with an elliptical cross section are provided in the tip portion 32b of the stator teeth of the stator core 30 shown in Fig. 7(a), and the long side of the ellipse is in the tooth direction (radial direction). Fig. 7(a) shows the case where two small holes 73a, 73b are provided, but three or more small holes may be provided. The tip portion 32b of the stator teeth of the stator core 30 shown in Fig. 7(b) is provided with small holes 73a, 73b having an elliptical cross section, with the long side of the ellipse being in the direction of rotation. Fig. 7(b) shows the case where two small holes 73a, 73b are provided, but three or more small holes may be provided. The stator teeth tip portion 32b of the stator core 30 shown in Fig. 7(c) is provided with small holes 73a, 73b having an elliptical cross-sectional shape, with the long side of the ellipse tilted relative to the teeth base imaginary center line A. Fig. 7(c) shows the case where two small holes 73a, 73b are provided, but three or more small holes may be provided.

[0028] As shown in Figures 6(a) to 7(c), the cross-sectional shape of at least one of the small holes 71a, 71b, 72a, 72b, 73a, 73b can be a rectangle, a triangle, a polygon, or an ellipse, and since the rectangle, triangle, polygon, or ellipse has straight lines, the minimum distance between the small holes 71a, 71b, 72a, 72b, 73a, 73b and the small holes 71a, 71b, 72a, 72b, 73a, 73b can be stably secured, and variations in magnetic resistance due to processing errors can be suppressed. Furthermore, by arranging the small holes 73a, 73b side by side and inclining them with respect to the tooth base imaginary center line A, the magnetic flux flow around the small holes 73a, 73b can be changed.

[0029] In the stator tooth tip portion 32b of the stator core 30 shown in FIG. 7(d), two small holes 70a, 70b are arranged at different distances from the opposing surface . Three small holes 70a, 70b, and 70c are provided in a tip portion 32b of a stator tooth of a stator core 30 shown in FIG. 7(e), and the small hole 70c is disposed at a different distance from the opposing surface 35 than the two small holes 70a, 70b.

[0030] By arranging the small holes 70a, 70b, and 70c as shown in Figures 7(d) and 7(e), the arrangement can be made according to the magnetic flux acting on the stator 3b as the rotor 3a rotates and the force in the direction of the stator teeth 32.This allows the flow of magnetic flux to be adjusted, and fluctuations in the force in the direction of the teeth (radial direction) can be reduced while maintaining the same torque as when the small holes 70a, 70b, and 70c are not provided.

[0031] Two small holes 70a, 70d are provided in the tip portion 32b of the stator teeth of the stator core 30 shown in Fig. 7(f), and the two small holes 70a, 70d are different in size. In this manner, the sizes of the small holes 70a, 70d may be different. Note that the sizes of the small holes 70a, 70b, 70c, 70d, 71a, 71b, 72a, 72b, 73a, 73b may also be different in Figs. 6(a) to 7(e).

[0032] By using the permanent magnet synchronous motor 3 according to this embodiment, it is possible to realize a compressor 10 that has low noise due to low vibration and is highly efficient without reducing torque. Moreover, equipment using the compressor 10 according to this embodiment can achieve low noise due to low vibration, and high efficiency.

[0033] FIG. 8 is a configuration diagram showing a main part of a compressor using a permanent magnet synchronous motor according to another embodiment of the present invention. 8(a) shows the arrangement of a compression mechanism 2 that compresses refrigerant gas and a permanent magnet synchronous motor 3 that drives the compression mechanism 2. The compression mechanism 2 and the permanent magnet synchronous motor 3 are connected by a shaft 8. The compression mechanism 2 is a rotary compression mechanism. The permanent magnet synchronous motor 3 has a rotor 3a and a stator 3b. The stator 3b is configured by stacking a plurality of stator cores 30 in the axial direction of the rotating shaft 8 of the rotor 3a. As described with reference to FIG. 2, the stator core 30 has an annular stator yoke 31 and a plurality of stator teeth 32, with slots 40 formed between the stator teeth 32, and windings 50 arranged in the slots 40. In this embodiment, the stator cores 30 used include a stator core 30a having small holes 70a, 70b, and 70c formed therein, and a stator core 30b having no small holes 70a, 70b, and 70c formed therein.

[0034] Fig. 8(b) shows a stator core 30a in which the small holes 70a, 70b, and 70c are formed, and Fig. 8(c) shows a stator core 30b in which the small holes 70a, 70b, and 70c are not formed. The stator core 30a shown in Fig. 8(b) is the stator core 30 already described in Fig. 6(a). Then, as shown in Figure 8(a), the stator core 30b that does not have the small holes 70a, 70b, 70c is stacked on the compression mechanism 2 side, and the stator core 30a that has the small holes 70a, 70b, 70c is stacked on the side away from the compression mechanism 2. The variation in the tooth direction (radial direction) force of stator core 30a is smaller than the tooth direction (radial direction) force of stator core 30b. Therefore, particularly in a rotary compressor in which rotor 3a is cantilevered by compression mechanism 2, by arranging stator core 30a, which has smaller variation in tooth direction (radial direction) force, at a position far from compression mechanism 2, it is possible to reduce the deflection of shaft 8. When the rotor 3a is supported at one end by the compression mechanism 2, the air gap is likely to become eccentric due to tilt caused by deflection of the shaft 8, and the air gap becomes narrower the farther from the compression mechanism 2, resulting in increased friction loss. By arranging the stator core 30a at a position where the air gap becomes narrower as in this embodiment, the magnetic attraction force acting there in the teeth direction (radial direction) can be reduced, thereby reducing friction loss and deflection of the shaft 8, thereby providing a compressor 10 with low noise due to low vibration and high reliability.

[0035] Although FIG. 8(a) shows a compressor 10 in which the compression mechanism 2 is disposed below the permanent magnet synchronous motor 3, the same applies to a compressor in which the compression mechanism 2 is disposed above the permanent magnet synchronous motor 3, or a compressor in which the compression mechanism 2 and the permanent magnet synchronous motor 3 are disposed horizontally. Also, Figure 8(b) shows the stator core 30 shown in Figure 6(a), but the same applies to the stator core 30 shown in Figures 3, 6(b) to 6(e), and 7(a) to 7(f).

[0036] FIG. 9 is a graph showing the teeth direction (radial direction) force and torque according to the embodiment shown in FIG. 9(a) shows the relationship between the tooth direction (radial direction) force acting on one stator tooth tip 32b and the rotation angle of the rotor 3a. Comparative Example 1 uses only the stator core 30a, and Comparative Example 2 uses only the stator core 30b without small holes. As the rotor 3a rotates, the stator teeth tip 32b receives a teeth-direction (radial) force with a periodic component according to the number of rotor magnetic poles. This embodiment is a six-pole motor, and the teeth-direction (radial) force acting on one stator tooth tip is a teeth-direction (radial) force with one periodic component at a rotation angle of 60°. In this embodiment, the motor is three-phase, and the fluctuation in the force acting on the stator teeth tips 32b is out of phase with respect to the teeth direction (radial direction) by 120° in electrical angle and 40° in rotation angle. A large fluctuation range of the force in the tooth direction (radial direction) causes large vibrations in the stator teeth 32 and therefore large vibrations in the motor, which is a factor in large vibrations in general rotary compressors and scroll compressors in which the outer periphery of the stator 3b is fixed in contact with the outer wall of the compressor 10. By reducing the fluctuation range of the force in the teeth direction (radial direction), a motor and compressor 10 with low vibrations can be achieved. The tooth direction (radial direction) force does not act uniformly on the stator tooth tips 32b, but rather the locations at which it acts locally change with the rotation of the rotor 3a. According to this embodiment, as shown in Fig. 9(a), it is possible to effectively reduce the tooth direction (radial direction) force acting locally with the rotation of the rotor 3a. The tooth direction (radial direction) fluctuating force ratio is 91% in Comparative Example 1 using only the stator core 30a compared to Comparative Example 2 using only the stator core 30b, which is a conventional example, and the average fluctuating force ratio between the two is 95%.

[0037] 9(b), comparing the torque of Comparative Example 1 in which the stator core 30 is composed of only the stator core 30a, Comparative Example 2 in which the stator core 30 is composed of only the stator core 30b, and this embodiment (stator core 30a and stator core 30b), it is found that the maximum and minimum torque values ​​of this embodiment are significantly reduced, and torque pulsation is reduced by half. The reduction in torque pulsation reduces vibration in the torsional direction, and also contributes to improved controllability because the torque fluctuation relative to the command current is small.

[0038] FIG. 10 is a configuration diagram showing a main part of a compressor using a permanent magnet synchronous motor according to still another embodiment of the present invention. 10(a) shows the arrangement of a compression mechanism 2 that compresses refrigerant gas and a permanent magnet synchronous motor 3 that drives the compression mechanism 2. The compression mechanism 2 and the permanent magnet synchronous motor 3 are connected by a shaft 8. The compression mechanism 2 is the scroll compression mechanism shown in FIG. The permanent magnet synchronous motor 3 has a rotor 3a and a stator 3b. The stator 3b is configured by stacking a plurality of stator cores 30 in the axial direction of the rotating shaft 8 of the rotor 3a. As described with reference to FIG. 2, the stator core 30 has an annular stator yoke 31 and a plurality of stator teeth 32, with slots 40 formed between the stator teeth 32, and windings 50 arranged in the slots 40. In this embodiment, the stator cores 30 used include a stator core 30a having small holes 70a, 70b, and 70c formed therein, and a stator core 30b having no small holes 70a, 70b, and 70c formed therein. Fig. 10(b) shows a stator core 30a in which the small holes 70a, 70b, and 70c are formed, and Fig. 10(c) shows a stator core 30b in which the small holes 70a, 70b, and 70c are not formed. The stator core 30a shown in Fig. 10(b) is the stator core 30 already described in Fig. 6(a).

[0039] Then, as shown in Figure 10(a), stator cores 30b that do not have small holes 70a, 70b, 70c are stacked on the side of the compression mechanism unit 2 and on the side away from the compression mechanism unit 2, and stator cores 30a that have small holes 70a, 70b, 70c are stacked between these stator cores 30b. The variation in the tooth direction (radial direction) force of stator core 30a is smaller than the tooth direction (radial direction) force of stator core 30b. Therefore, particularly in a scroll compressor in which rotor 3a is supported at both ends by compression mechanism 2 and bearing 7b, by locating stator core 30a, which experiences smaller variation in the tooth direction (radial direction) force, in a position farther from compression mechanism 2, it is possible to reduce the deflection of shaft 8. When the rotor 3a is supported at both ends by the compression mechanism 2 and the bearing 7b, arranging the stator core 30a near the center between the shaft supports where shaft deflection is likely to occur reduces deflection of the shaft 8, thereby providing a highly reliable compressor 10 with low vibration and low noise. Note that when the compression mechanism 2 uses a highly rigid shaft 8 that is larger in diameter or longer in shaft length than the bearing 7b, the stator core 30b may be arranged on the compression mechanism 2 side, and the stator core 30a may be arranged in a position distant from the compression mechanism 2 side.

[0040] Although FIG. 10(a) shows a compressor in which the compression mechanism 2 is disposed above the permanent magnet synchronous motor 3, the same applies to a compressor in which the compression mechanism 2 is disposed below the permanent magnet synchronous motor 3, or to a compressor 10 in which the compression mechanism 2 and the permanent magnet synchronous motor 3 are disposed horizontally. Also, Figure 10(b) shows the stator core 30 shown in Figure 6(a), but the same applies when using the stator core 30 shown in Figures 3, 6(b) to 6(e), and 7(a) to 7(f). The small hole arrangement core shown in this embodiment may also be used in a motor that uses a so-called split core, in which a stator is divided in the circumferential direction, has high density windings wound around it, and then is arranged in the circumferential direction and combined, or in a motor that uses a stator in which high density windings are applied with a portion of the stator yoke joined, and then the yoke portion is deformed or moved to fit tightly in the circumferential direction. Split-core stators and stators with parts of the stator yoke joined have lower rigidity than typical stators that are one unit in the circumferential direction. Also, in a T-shaped stator where the teeth and yoke are at right angles due to high-density windings, the width of the yoke between the teeth is small, which also reduces rigidity. The permanent magnet synchronous motor of the present invention can reduce the fluctuation of radial force even with respect to split cores, achieving low noise due to low vibration and high efficiency. [Industrial Applicability]

[0041] The permanent magnet synchronous motor of the present invention is suitable for scroll compressors and rotary compressors, but can also be used for reciprocating compressors and other compressors. [Explanation of symbols]

[0042] 1. Airtight container 2. Compression mechanism 2a Fixed Scroll 2b Swivel Scroll 3. Permanent magnet synchronous motor 3a Rotor 3b Stator 4 Oil storage section 5 Suction pipe 6 Discharge pipe 7a Main bearing member 7b Bearings 8 Shaft (rotor axis) 8a Eccentric shaft part 9 Rotation restraint mechanism 10 Compressor 11 Permanent magnets 30, 30a, 30b Stator core 31 Stator yoke 32 Stator teeth 32a Stator teeth base 32b Stator tooth tip 35 Opposite Surface 40 Slots 50 Windings 61 Condenser 62 Pressure reducing device 63 Evaporator 70 Small hole group 70a, 70b, 70c, 70d, 71a, 71b, 72a, 72b, 73a, 73b small hole 70x Virtual Center t Width dimension A Teeth base virtual center line

Claims

1. A rotor that is rotatably disposed around a rotation axis; a stator disposed between the rotor and an air gap; having The stator includes: an annular stator yoke centered on the rotation axis; A plurality of stator teeth extending from the stator yoke toward the rotor; Slots formed between the stator teeth; having A winding is disposed in the slot; The stator teeth are a stator teeth base around which the winding is wound; a stator teeth tip portion that forms a surface facing the rotor at a tip of the stator teeth base portion; having A group of small holes, each group consisting of at least two small holes, is disposed at the tip of the stator teeth; The cross-sectional shape of each of the small holes is a circle having the same diameter, A dimension between the small holes and the opposing surface is set smaller than the diameter of the small holes, and a distance from each of the small holes to the opposing surface is set constant, so that each of the small holes is arranged in a line along the opposing surface; The small holes are arranged in a section where the fluctuation range of the tooth direction force acting on the tip portion of the stator teeth becomes small. A permanent magnet synchronous motor.

2. the center of the circumferential width dimension of the stator teeth base is defined as a teeth base imaginary center line, The small holes are arranged such that a virtual center of the small hole group consisting of the plurality of small holes is located in a counter rotation direction of the rotor from the virtual center line of the tooth base.

2. The permanent magnet synchronous motor according to claim 1 .

3. The number of the small holes is three or more.

3. The permanent magnet synchronous motor according to claim 1 or 2.

4. The stator is configured by stacking a plurality of stator cores in the axial direction of the rotating shaft, The small holes are formed in a part of the stator cores, The other stator cores are not provided with the small holes.

4. The permanent magnet synchronous motor according to claim 1, wherein the first and second poles are arranged in a first direction and a second direction, respectively.

5. Using the permanent magnet synchronous motor according to claim 4, The permanent magnet synchronous motor and the compression mechanism are connected by a shaft, The stator core in which the small hole is not formed is disposed on the compression mechanism side, The stator core in which the small hole is formed is disposed on a side away from the compression mechanism. A compressor characterized by:

6. Using the permanent magnet synchronous motor according to any one of claims 1 to 4, The permanent magnet synchronous motor and the compression mechanism are connected by a shaft, The refrigerant is compressed by the compression mechanism. A compressor characterized by:

7. A compressor, a condenser, a pressure reducing device, and an evaporator according to claim 5 or claim 6, connected in a ring by piping. The device characterized by:

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