JP2012223068A - Rotary electric machine - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a rotary electric machine that reduces influence of deterioration in magnetic characteristics and then reduces generation of an eddy current.SOLUTION: A rotary electric machine 10 includes a sealed container 12, a stator 14 stored in the container 12, and a rotor 16 arranged inwardly from the stator 14. The rotor 16 does not have a magnet 66 arranged on a vertical line from a weld zone 72 to a rotary shaft 64. When the rotor 16 rotates, the magnet 66 is not arranged on the vertical line at any angle of rotation of the rotor 16.

Description

  The present invention relates to a rotating electrical machine used for a compressor or the like.

  Conventionally, a rotating electrical machine has been developed in which a stator and a rotor are arranged in a sealed container (Patent Document 1, etc.). The container has a cylindrical shape, and both ends thereof are sealed. The stator is annular, and the stator is fixed to the inner surface of the container. A rotor is arranged inside the stator. The stator and the rotor are a laminate of a plurality of electromagnetic steel plates.

  As means for fixing the stator, shrink fitting is often used in which the container is thermally expanded to fit the stator, and the container is cooled and fixed. In this case, compressive stress is generated on the stator. The compressive stress is estimated to be about 50 to 100 MPa, for example. Since the iron loss of the electrical steel sheet is increased by the compressive stress, it is necessary not to generate the compressive stress.

  An example of a method that does not generate compressive stress is welding. If it is welding, it is possible to make a clearance fit between a stator and a container. It is possible to make the compressive stress with respect to the electromagnetic steel plate of a stator zero (nonpatent literature 1).

  However, since thermal stress is applied to the electrical steel sheet by welding, there is a deterioration in the magnetic properties of the electrical steel sheet due to thermal stress. Moreover, since a welding part short-circuits several electromagnetic steel plates, many magnetic flux passes along a welding part and generation | occurrence | production of an eddy current is also anxious. Eddy current loss occurs due to heat generation by eddy current.

JP 2010-236421 A Proceedings of 2010 Annual Conference of Japan Society of Refrigerating and Air Conditioning Engineers D324-2

  An object of the present invention is to provide a rotating electrical machine in which the influence of deterioration of magnetic characteristics is reduced and the generation of eddy currents is reduced.

  The rotating electrical machine of the present invention includes a cylindrical container, a stator that is housed in the container and is wound on a stator core that is formed by laminating electromagnetic steel plates, and an inner side of the stator. A rotor core that is configured by laminating electromagnetic steel plates and rotates about a rotation shaft attached to the center; a plurality of magnets embedded in the rotor core; and the container and the stator are fixed. For welding. In the rotor core, no magnet is arranged in a region on a vertical line from the welded portion toward the rotation axis.

  In the rotation axis direction, the magnets are arranged so that the lengths in the rotation axis direction are substantially the same and the magnetic poles are the same, and the weld is provided at the center of the stator core or the rotor core in the rotation axis direction. Moreover, the said welding part may be provided in the edge part of the stator core or rotor core in a rotating shaft direction. Furthermore, you may provide a welding part in both a center and an edge part.

  The length in the rotation axis direction in the region where the magnet is not disposed is larger than the thickness of the electromagnetic steel plate of the stator core or the electromagnetic steel plate of the rotor core.

  The container is a sealed container in which both ends of a cylindrical shape are sealed. The rotating electrical machine is applied to a hermetic compressor.

  In the present invention, even if there is a deterioration in magnetic characteristics due to thermal stress, a magnet is not disposed in a region on the vertical line from the welded portion to the rotation axis, so that the magnetic flux of the rotor is a portion where the magnetic characteristics are deteriorated due to the welding of the stator. The effect on the characteristics of the rotating electrical machine is small. Moreover, since the passage of magnetic flux to the welded portion is reduced, the generation of eddy current is reduced, and eddy current loss is reduced.

It is a figure which shows the structure of the rotary electric machine applied to the compressor. It is a figure which shows the structure of a rotary electric machine. It is the sectional view on the AA line in FIG. It is the BB sectional view taken on the line in FIG. It is a figure which shows the example of the position of a welding part. It is a figure which shows the example which combined the position of the welding part of FIG. 2 and FIG. It is the figure by which the end plate of the nonmagnetic material was arrange | positioned on the perpendicular line toward a rotating shaft from the welding part. It is a figure without a back yoke being arrange | positioned on the perpendicular line toward a rotating shaft from a welding part, and without a tooth | gear and a rotor core.

  The rotating electrical machine of the present invention will be described with reference to the drawings. A rotating electrical machine used for a refrigerant rotary compressor used in an air conditioner or the like will be described as an example.

  The rotating electrical machine 10 includes a hermetically sealed container 12, a stator 14 housed in the container 12, and a rotor 16 disposed inside the stator 14 (FIGS. 1 and 2).

  The container 12 includes a cylindrical pipe 18. The container 12 can be formed, for example, by drawing a steel plate. Both ends of the pipe 18 are closed by cap-shaped top 20 and bottom 22 respectively. The stator 14 and the rotor 16 are accommodated inside the pipe 18.

  Since the rotating electrical machine 10 is applied to the compressor 24, a compression mechanism 26 is provided below the stator 14 and the rotor 16 in the pipe 18. The bottom 22 is disposed below the compression mechanism 26. Lubricating oil is stored in the bottom 22. An accumulator 28 for supplying a refrigerant to the compression mechanism 26 is provided outside the container 12. The accumulator 28 is connected to the compression mechanism 26.

  The accumulator 28 is provided with an inlet pipe 30 for introducing the refrigerant into the accumulator 28 and an outlet pipe 32 for supplying the gaseous refrigerant separated inside the accumulator 28 to the compression mechanism 26. The outlet pipe 32 is attached to a connection port 34 provided in the pipe 18. A gaseous refrigerant is sent to the compression mechanism 26 by the rotation of the rotor 16.

  The compression mechanism 26 has a two-stage structure including a front cylinder 36 and a rear cylinder 38. The front cylinder 36 includes a piston 42 attached to the cylinder chamber 40 and the rotation shaft 64 of the rotor 16. As the piston 42 rotates eccentrically, the refrigerant is sucked into the cylinder chamber 40 and compressed. Similar to the front cylinder 36, the rear cylinder 38 is also provided with a cylinder chamber 44. When the piston 46 of the cylinder chamber 44 rotates eccentrically, the refrigerant is sucked into the cylinder chamber 44 and compressed.

  A discharge pipe 48 for discharging the refrigerant compressed by the compression mechanism 26 to the outside of the container 12 is attached to the top 20. Further, a terminal 50 connected to the coil of the stator 14 is provided. Outside the container 12, the terminal 50 is connected to an inverter circuit.

  The stator 14 includes an annular back yoke 52, a plurality of teeth 54 extending from the back yoke 52 toward the annular center, a slot 56 formed between adjacent teeth 54, a coil 58 disposed in the slot 56, a back A slot cell 60 is provided to insulate the coil 58 from the yoke 52 and the tooth 54 (FIGS. 3 and 4).

  The back yoke 52 and the teeth 54 are integrated, and constitute a stator core 55 by them. The stator core 55 is formed by laminating a plurality of electromagnetic steel plates made of a soft magnetic material via an insulating layer. The teeth 54 are arranged at equal intervals. The slot 56 is a space between the teeth 54, and the coil 58 is disposed in this space. The slot cell 60 is an insulating film such as a PET (polyethylene terephthalate) film. The slot cell 60 is disposed between the stator core 55 and the coil 58 to ensure insulation between the stator core 55 and the coil 58.

  The rotor 16 includes a rotor core 62 in which a plurality of electromagnetic steel plates made of a soft magnetic material are stacked via an insulating layer, a rotating shaft 64 attached to the rotor core 62, and a plurality of permanent magnets 66 embedded in the rotor core 62. Is provided. The thickness of the electromagnetic steel sheet may be the same as the thickness of the electromagnetic steel sheet constituting the stator core 55. The magnet 66 is provided with a groove 71 in the rotor core 62 and is embedded in the groove 71. The rotor core 62 is appropriately provided with a groove (flux barrier) for blocking magnetic flux. An end plate 68 for preventing the magnet 66 from popping out is attached to the end of the rotor core 62. Each electromagnetic steel sheet has a disk shape and has a circular hole in the center of each electromagnetic steel sheet. A rotating shaft 64 is inserted into the hole and fixed.

  The plurality of magnets 66 are arranged so that the magnetic poles adjacent in the circumferential direction are different, and are arranged so that the magnetic poles are the same in the rotation axis direction. The number of magnets 66 arranged in the circumferential direction is an even number, and the magnets 66 are arranged at target positions around the rotation shaft 64. In FIG. 2, two magnets 66 are arranged in the rotation axis direction (y-axis direction). For example, in the two magnets 22 arranged side by side, the two magnetic poles on the center side of the rotor core 62 are N or S poles. A region 70 where no magnet 66 is disposed is provided between the magnets.

  The region 70 where the magnet 66 is not disposed in the groove 71 is provided as follows. By matching the magnetic poles of the two magnetic poles arranged in the rotation axis direction (y-axis direction) on the radially outer side with respect to the rotation axis, a region 70 where the magnets 66 are not arranged can be formed by repulsion between the magnets. A nonmagnetic spacer may be provided between the magnets. In the groove 71 for embedding the magnet 66 in the rotor core 62, only the region 70 where the magnet 66 is not disposed in the groove 71 is narrowed in the radial direction with respect to the rotation axis, or provided with a convex portion. The region 70 may be formed so as not to contact. When one magnet 66 is formed, a non-magnetized portion may be formed, and the non-magnetized portion may be a region 70 where the magnet 66 is not disposed. The length in the rotation axis direction in the region 70 where the magnet 66 is not disposed is set to be larger than the thickness of one electromagnetic steel sheet.

  The outer periphery of the back yoke 52 and the inner surface of the container 12 are fixed by a welded portion 72. In order to perform welding, a welding hole is provided at a welding position in the container 12. The stator 14 is placed in the container 12 and welded from the outside of the container 12 so as to fill the welding hole.

  In the rotor 16, the magnet 66 is not arranged on the vertical line Lv from the welded portion 72 toward the rotation shaft 64. A region 70 where the magnet 66 is not disposed is on the vertical line Lv. When the rotor 16 rotates, the magnet 66 is not disposed on the vertical line Lv regardless of the rotation angle of the rotor 16 (FIG. 3). That is, if the welded portion 72 is disposed on a cross section (xz plane) perpendicular to the rotation axis direction (y-axis direction), the magnet 66 is not disposed.

  Although a plurality of welds 72 are provided, the positions of the welds 72 in the rotation axis direction are the same. Accordingly, the plurality of welds 72 are arranged on the same xy plane, and the container 12 is cylindrical, so that the welds 72 are arranged in the circumferential direction. In the region where there is no welded portion 72, the magnet 66 is disposed in a cross section (xz plane) perpendicular to the rotation axis direction (y-axis direction) (FIG. 4).

  The position of the welded portion 72 may be provided at the center of the rotor 16 in the rotation axis direction. In the rotor 16, when the two magnets 66 are arranged in the direction of the rotation axis and the lengths in the direction of the rotation axis of the two magnets 66 are substantially the same, the area where the magnet 66 is not arranged at the center of the rotor 16. This is because 70 is formed.

  The stator 14 is fitted with a very small gap (not shown) with respect to the inner surface of the pipe 18 and welded. Due to the gap, no compressive stress is generated in the stator 14. Iron loss does not occur in the electromagnetic steel sheet of the stator 14. The stator 14 may be slightly pressed into the inner surface of the pipe 18. This is because the stress applied to the stator core 55 can be reduced by reducing the tightening allowance compared to shrink fitting.

  Although the electromagnetic stress of the electrical steel sheet is deteriorated due to the thermal stress when forming the welded portion 72, the magnet 66 is not disposed on the vertical line from the welded portion 72 to the rotating shaft 64. Since the magnetic flux from the magnet 66 with respect to the deteriorated portion of the magnetic characteristics is reduced, the adverse effect on the rotational characteristics of the rotor 16 can be reduced. Further, the passage of magnetic flux to the welded portion 72 is reduced as compared with the conventional case, and the eddy current in the welded portion 72 is reduced. Therefore, eddy current loss can be reduced.

  In the above embodiment, the welded portion 72 is provided at a position corresponding to the center of the rotor 16 in the direction of the rotation axis. However, the welded portion 72 may be provided at portions corresponding to both ends of the rotor 64 (FIG. 5). Similar to the above embodiment, the magnet 66 is not disposed on the vertical line Lv from the welded portion 72 toward the rotation shaft 64. Moreover, you may provide the weld part 72 in the part which hits the center and both ends of the rotating shaft direction in the rotor 64 (FIG. 6).

  Depending on the shape of the magnet 66, the position is not limited to the above-described position. It may be other than the center or both ends of the rotor 64 in the rotation axis direction. The number of welds 72 provided in the rotation axis direction is not limited, and the number of magnets 66 arranged in the rotation axis direction is appropriately changed depending on the number of welds 72.

  In addition, although the welded portion 72 is provided at the center of the rotor 64 in the direction of the rotational axis and at the portions corresponding to both ends, the welded portion 72 may be provided at the portion of the stator 14 that corresponds to the center in the rotational axis direction and both ends. The magnet 66 is not disposed on the vertical line from the welded portion 72 toward the rotating shaft 64. When the welded portion 72 is provided at a portion corresponding to the end of the stator 14, the rotating shaft 64 is on the vertical line from the welded portion 72 toward the rotating shaft 64, but the rotor core 62 may not be provided. Alternatively, a non-magnetic end plate 68 may be disposed on the vertical line Lv (FIG. 7).

  In some cases, only the back yoke 52 is present on the vertical line Lv from the welded portion 72 to the rotating shaft 64, and the teeth 54 and the rotor core 62 are absent (FIG. 8). In this case, the stator core having only the back yoke 52 and the stator core having the teeth 54 and the back yoke 52 need to be fixed by caulking or the like. If the welded portion 72 is formed at a location where the rotor core 62 is not present, it is not particularly necessary to divide the magnet 66 in the rotation axis direction.

  Depending on the shape of the magnet 66, the position is not limited to the above-described position. It may be other than the center or both ends of the rotation direction of the stator 14. The number of welded portions 72 provided in the rotation axis direction is not limited, and the number of welded portions is appropriately changed depending on the shape of the magnet 66. The configuration of the compressor 24 is arbitrary, and the configuration without the accumulator 28 and the compression mechanism 26 may have a single-stage structure instead of the two-stage structure.

  The present invention can be applied not only to the hermetic compressor 24 but also to other motors and generators that require welding.

  In addition, the present invention can be carried out in a mode in which various improvements, modifications, and changes are added based on the knowledge of those skilled in the art without departing from the gist thereof. Each embodiment is not independent or exclusive, and may be implemented in combination as appropriate.

10: rotating electrical machine 12: container 14: stator 16: rotor 18: pipe 20: top 22: bottom 24: compressor 26: compression mechanism 28: accumulator 30: inlet pipe 32: outlet pipe 34: connection port 36: Front cylinder 38: Rear cylinder 40, 44: Cylinder chamber 42, 46: Piston 48: Discharge pipe 50: Terminal 52: Back yoke 54: Teeth 55: Stator core (stator core)
56: Slot 58: Coil 60: Slot cell 62: Rotor core (rotor core)
64: Rotating shaft 66: Magnet 68: End plate 70: Area without magnet 71: Groove 72: Welded part

Claims (5)

A cylindrical container;
A stator that is housed in the container and is wound around a stator core formed by laminating electromagnetic steel plates; and
A rotor core that is arranged inside the stator, is configured by laminating electromagnetic steel plates, and rotates about an axis of rotation attached to the center;
A plurality of magnets embedded in the rotor core;
A welded portion welded to fix the container and the stator;
With
In the rotor core, a rotating electric machine in which no magnet is arranged in a region on a vertical line from a welded portion toward a rotating shaft. The magnets are arranged such that in the axial direction of the rotating shaft, the length in the rotating shaft direction is substantially the same, and the magnetic poles are the same,
The rotating electrical machine according to claim 1, wherein the welded portion is provided at the center of the stator core or the rotor core in the direction of the rotation axis. 3. The rotating electrical machine according to claim 1, wherein the welded portion is provided at an end portion of the stator core or the rotor core in the rotation axis direction. The rotating electrical machine according to any one of claims 1 to 3, wherein a length in a rotation axis direction in a region on the vertical line is larger than a thickness of the electromagnetic steel plate of the stator or the electromagnetic steel plate of the rotor core. The rotating electrical machine according to any one of claims 1 to 4, wherein the container is a sealed container in which both ends of a cylindrical shape are sealed.

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