JP2007202254A - Permanent magnet synchronous motor and compressor using the motor - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To reduce the size of a permanent magnet synchronous motor and the size of a compressor that uses the motor. <P>SOLUTION: The permanent magnet synchronous motor comprises a stator having a plurality of slots that are wound with windings, and a rotor 1 arranged inside the stator. In the motor, the rotor has a plurality of slots, conductive bars 3 are arranged in the slots, and a plurality of permanent magnets 5 per magnetic pole are arranged inside the conductive bars. The conductive bars should be arranged on a line 11 that connects the center between centers of the adjacent permanent magnets and the center of the rotor. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a permanent magnet synchronous motor and a compressor using the permanent magnet synchronous motor, and more particularly, a permanent magnet synchronous motor including a conductor bar near the outer periphery of a rotor and a permanent magnet inside the conductor bar and the same. It is suitable for a compressor.

As a conventional compressor motor, for example, a permanent magnet synchronous motor composed of a cage conductor and a permanent magnet as described in Patent Document 1 is known. Such a permanent magnet synchronous motor has an advantage that it can be directly operated by a commercial power source without using an inverter control device.

JP 2004-56887A (particularly, paragraphs “0042” and “0043” and FIG. 12)

  The compressor and the synchronous motor of Patent Document 1 have a problem that vibration and noise occur during synchronous operation.

  For example, when the compressor is mounted on an outdoor unit for an air conditioner, the outdoor unit for the air conditioner may be placed in a place with little space such as a veranda, so that there is a problem that the place is limited because the space is large. . In the compressor of Patent Document 1, the size of the electric motor is increased, and there is a problem that the installation place is limited when an outdoor unit for an air conditioner using a compressor equipped with such an electric motor is installed.

  One of the objects of the present invention is to obtain a compressor and a permanent magnet synchronous motor with less vibration and noise.

  Another object of the present invention is to reduce the size of the compressor and the permanent magnet synchronous motor.

  According to an aspect of the present invention, the compressor includes a suction port for sucking the refrigerant, a compression mechanism unit that compresses the refrigerant sucked from the suction port, a discharge port that discharges the refrigerant compressed by the compression mechanism unit, and a compression mechanism unit. The permanent magnet synchronous motor includes a stator having a plurality of slots, and windings wound around the slots, and a rotor disposed inside the stator. The rotor has a plurality of slots, a conductor bar is provided in the slot, a plurality of permanent magnets are arranged per magnetic pole inside the conductor bar, and other than on the line connecting the center of the rotor and the center of the permanent magnet The conductor bar is arranged only in the portion.

  Further, according to another aspect of the present invention, the synchronous motor includes a stator having a plurality of slots, and windings wound around the slots, and a rotor disposed inside the stator, The rotor has a plurality of slots, a conductor bar is provided in the slot, a plurality of permanent magnets are arranged per magnetic pole inside the conductor bar, and the rotor is not on a line connecting the center of the rotor and the center of the permanent magnet. The conductor bar is arranged only in the portion.

  In another aspect of the present invention, the compressor includes a suction port for sucking the refrigerant, a compression mechanism unit for compressing the refrigerant sucked from the suction port, a discharge port for discharging the refrigerant compressed by the compression mechanism unit, and a compression mechanism. The permanent magnet synchronous motor includes a plurality of slots, a stator having windings wound around the slots, and a rotor disposed inside the stator. And the rotor has a plurality of slots, a conductor bar is provided in the slot, a plurality of permanent magnets are arranged per magnetic pole inside the conductor bar, and the center of the permanent magnet and the center of the rotor The conductor bar is arranged only near the line connecting the two.

  Further, in the above compressor, the shape of the permanent magnet is preferably a trapezoid in which the length of the outer peripheral side is longer than the length of the inner peripheral side.

  Furthermore, in the above-described compressor, it is desirable that a convex yoke portion for supporting the permanent magnet in the circumferential direction is provided between adjacent permanent magnets.

  Further, in the above compressor, it is desirable that a connecting yoke portion is provided between adjacent permanent magnets.

  Furthermore, in the above compressor, it is desirable that the ratio between the number of conductor bars and the number of permanent magnets is 3: 1.

  Furthermore, in the above compressor, it is desirable that the number of stator slots is 30 and the number of conductor bars is 22.

  According to the present invention, vibration and noise of the compressor and the electric motor can be reduced. Moreover, according to this invention, a compressor and an electric motor can be reduced in size. Furthermore, according to this invention, a compressor and an electric motor can be reduced in size.

  Examples of the present invention will be described below.

  FIG. 1 (1A) is a cross-sectional view of the rotor according to the first embodiment of the present invention. As shown in FIG. 1, the rotor 1 includes a plurality of squirrel-cage-type conductor bars 3 on the inner periphery of the rotor core 2 provided on the shaft 10, and the rotor core 2 on the inner periphery side of the conductor bar 3. A plurality of rectangular (or square) permanent magnets 5 mainly composed of rare earth (or ferrite) embedded in a plurality of magnet insertion holes 4 in a concentric virtual arc having a constant width with the center of the center as a center. It is arranged and configured to have two poles. A stator (not shown) is provided with a slot, and a stator winding is wound in the slot. The gap 8 is provided to reduce leakage magnetic flux (magnetic flux returning from the permanent magnet to the permanent magnet without passing through the stator). In the present embodiment, the conductor bar 3 disposed outside the permanent magnet is disposed only on the line 11 (including the vicinity of the line) connecting the center 14 of the permanent magnet and the rotor center 12. Here, the diameter of the conductor bar is about half of the width of the permanent magnet.

FIG. 9 shows the magnetic flux distribution of Example 1. The solid line in FIG. 6 is a schematic diagram of the magnetic flux density distribution in the outer periphery of the rotor of the first embodiment, and shows only the magnetic flux density of the magnetic flux emitted from the central permanent magnet. In FIG. 6, the horizontal axis indicates the position in the circumferential direction, and the vertical axis indicates the magnetic flux density emitted from the rotor outer peripheral surface. A solid line 901 in FIG. 6 indicates the position of the conductor bar of the first embodiment. Reference numeral 903 denotes the position of the permanent magnet of the first embodiment. A dotted line 904 indicates the magnetic flux density when the conductor bar 902 is arranged in addition to the conductor bar 901 of the first embodiment, and a solid line 905 indicates the magnetic flux density distribution of the first embodiment. As the magnetic flux density is more uniformly distributed (that is, the difference between the maximum value and the minimum value of the magnetic flux density is smaller), the torque pulsation due to the rotational position of the rotor can be suppressed, and vibration and noise during synchronous operation are reduced. be able to. From FIG. 6, because than the difference .DELTA.B ₁ between the maximum value and the minimum value of the magnetic flux density in the case of arranging the conductor bars 901 found the difference .DELTA.B ₂ between the maximum value and the minimum value of the magnetic flux density of Example 1 small, carried It can be seen that the rotating electric machine of Example 1 can reduce the torque pulsation and has less vibration and noise. That is, according to the first embodiment, the magnetic flux emitted from the permanent magnet to the outer peripheral portion of the rotor can be made uniform, and torque pulsation can be suppressed. Due to this action, the electric motor rotates smoothly, so that vibration and noise of the electric motor can be reduced.
Although the illustration of the stator is omitted in the first embodiment, the number of slots of the stator is 30, and the number of conductor bars is 22. The reason why the number of stator slots 30 and the number of conductor bars 22 are selected is based on the balance of restriction on teeth magnetic flux density calculated backward from the magnetic flux density of the gap and prevention of magnetomotive force harmonics. In particular, regarding the number of conductor bars 22, from the starting characteristics in manufacturing and the rule of thumb of vibration noise, when the number of stator slots is 30, the number of conductor bars 22 is appropriate.

  FIG. 11 is an enlarged view of the space between the permanent magnets of this embodiment. 1501 is a permanent magnet, 1502 is a gap, and the gap 1502 is provided to reduce leakage magnetic flux (magnetic flux that returns to the magnet without reaching the stator) from the permanent magnet. A convex yoke portion 1504 is provided between adjacent permanent magnets 1501 so that the magnet 1501 does not move during motor operation. For example, when the air gap 1502 is provided as shown in FIG. 12, the circumferential movement of the magnet 1501 during operation of the motor is supported by contact only with a line 1503 (represented by a point on FIG. 12). Therefore, during operation, stress concentrates on the portion of the permanent magnet that is in contact with the wire 1503, and the corner portion of the permanent magnet may be lost. However, as shown in FIG. 11, if the permanent magnet is supported by contact with the surface 1503, the contact area is wide and stress applied to the permanent magnet is dispersed, so that corners of the permanent magnet can be prevented from being chipped. .

  FIG. 1 (1B) is a diagram showing Example 2 of the rotor of the present invention. Description of the same parts as those in the first embodiment is omitted. The difference from the first embodiment is that the shape of the magnet is trapezoidal, and the length of the radially outer side of the magnet is larger than the length of the inner side. By making the shape of the permanent magnet trapezoidal, the outer circumference area of the magnet is increased, and the amount of magnetic flux generated from the permanent magnet interlinking with the windings wound on the stator increases. You can improve. Moreover, since the output in unit volume can be improved, the electric motor can be reduced in size. In the second embodiment, since the pseudo-arc-shaped magnetic pole is configured by the plurality of trapezoidal permanent magnets 5b, the magnetic characteristics are not different from the case where the arc-type magnet is used. However, since a trapezoidal magnet having a higher utilization rate than the arc type is used, the magnet production cost can be reduced.

  A manufacturing process of the trapezoidal magnet will be described with reference to FIG. The unit of FIG. 10 is mm. In the case of producing the trapezoidal magnet shown in FIG. 10, the magnet powder material is packed in a rectangular mold having a cross section of 1402, a pressure in a direction perpendicular to the cross section is applied, and a magnetic field is applied in the width direction. After forming and heat-treating, the rectangular block is cut along the cutting line. Since the trapezoidal magnet cannot use only a small portion 1403 of the raw material and has a high utilization rate with respect to the raw material, the magnet production cost can be reduced compared to the arc type magnet.

  According to the first embodiment, a plurality of permanent magnets are arranged per magnet of the rotor of the permanent magnet synchronous motor, and the shape of the permanent magnet is a trapezoid in which the length of the outer peripheral side is longer than the length of the inner peripheral side. As a result, the area outside the permanent magnet is increased and the magnetic flux emitted from the rotor is increased, so that the output per unit volume of the electric motor can be increased. Therefore, the electric motor can be reduced in size.

  FIG. 2 (2A) is a cross-sectional configuration diagram of Embodiment 3 of the rotor of the present invention. 2 (2A) is different from the first embodiment in that the conductor bar 3 is not arranged on the line 211 connecting the center 213 of the rotor and the center 212 of the magnet 25. FIG. As shown in FIG. 2 (2A), the rotor 21 rotates to the inner periphery side of the starting bar-shaped conductor bar 3 and the conductor bar 3 inside the outer periphery of the rotor core 22 provided on the shaft 10. A plurality of rectangular (or square) permanent magnets 25 mainly composed of rare earth (or ferrite) embedded in a plurality of magnet insertion holes 24b in a concentric virtual arc having a constant width with the center of the core core 22 being a center. The arrangement is such that the number of magnetic poles is two. Further, in order to reduce the leakage magnetic flux between the poles, holes 26 and 28 are provided between the poles via the connecting yoke portion 27.

  FIG. 8 shows the magnetic flux distribution of FIG. 2 (2A). Reference numeral 801 denotes a magnetic flux. FIG. 7 is a schematic diagram of the magnetic flux density distribution in the outer circumferential portion of the rotor of Example 3, and illustrates only the magnetic flux density of the magnetic flux emitted from the central magnet. In FIG. 7, the horizontal axis indicates the position in the circumferential direction, and the vertical axis indicates the magnetic flux density emitted from the rotor outer peripheral surface. A solid line 1002 in FIG. 7 indicates the position of the conductor bar of the third embodiment, and 1003 indicates a position of the permanent magnet of the third embodiment. A dotted line 1004 shows the magnetic flux density when 1001 conductor bars are additionally arranged in addition to the conductor bar 1002 of this embodiment, and a solid line 1005 shows the magnetic flux density distribution of this embodiment. The greater the total amount of magnetic flux that emerges from the rotor outer peripheral surface (in FIG. 7, the area surrounded by the magnetic flux density curve and the horizontal axis), the greater the output per unit volume of the motor, and the smaller the motor. I can plan. Moreover, efficiency and a power factor can be improved. From FIG. 7, the total magnetic flux amount of the third embodiment is larger than the total magnetic flux amount when the conductor bar 1001 is added, and the output per unit volume is larger in the third embodiment, and the motor can be downsized. I understand. This is because when the conductor bar 1001 is arranged, the conductor bar is located near the center of the permanent magnet where the amount of magnetic flux emitted from the permanent magnet is the largest. In Example 3, since the conductor bar is not arranged near the center of the magnet, it is considered that the reason is that the amount of magnetic flux is increased. That is, according to the third embodiment, by not arranging the conductor bar on the line connecting the center of the rotor and the center of the permanent magnet, the conductor bar blocks the magnetic flux from the center of the permanent magnet to the outer periphery of the rotor. Since many magnetic fluxes are emitted from the outer peripheral portion of the rotor, the output per unit volume of the electric motor can be increased. Therefore, the electric motor can be reduced in size.

FIG. 2 (2B) is a cross-sectional view of Embodiment 4 of the rotor of the present invention. The difference from the third embodiment is that the shape of the magnet is a trapezoid. By making the shape of the magnet trapezoid, efficiency can be improved as in the second embodiment.

Embodiment 5 of the rotor of the present invention will be described below with reference to FIG. 3 (3A). FIG. 3 (3A) is a cross-sectional configuration diagram of a rotor for explaining a fifth embodiment of the rotor of the present invention. As shown in FIG. 3 (3A), the rotor 41 is rotated on the inner periphery of the starting bar-shaped conductor bar 3 and the conductor bar 3 inside the outer periphery of the rotor core 42 provided on the shaft 10. A plurality of rectangular (or square) permanent magnets 45 mainly composed of rare earth (or ferrite) embedded in a plurality of magnet insertion holes 44 in a concentric virtual arc having a constant width with the center of the core 42 as a center. Are arranged so that the number of magnetic poles is two. The convex yoke portion 9 is provided between the adjacent permanent magnets 45 so as not to move the permanent magnets 45 during the operation of the electric motor. Further, two yokes 46 and 47 having a width of about 1 mm are provided between rectangular (or square) permanent magnets 45 constituting one magnetic pole.
If constituted in this way, the same operation as FIG. 2 (2A) can be obtained, and the passage of leakage magnetic flux can be reduced. Further, since the outer peripheral portion and the inner peripheral portion of the rotor are connected by the connecting yoke, it is possible to prevent the outer peripheral portion of the rotor from being damaged by centrifugal force, and the strength of the rotor can be further strengthened.

Embodiment 6 of the rotor of the present invention will be described with reference to FIG. 3 (3B). In FIG. 3 (3B), a rare earth (or ferrite) embedded in a plurality of magnet insertion holes 44b in a concentric virtual arc having a constant width with the center of the rotor core 42b as a center on the inner peripheral side of the conductor bar 3. Are arranged such that the number of magnetic poles is two, and two connecting yokes 46b and 47b are provided between the plurality of trapezoidal magnets constituting one magnetic pole. Even with this configuration, the rotor strength can be further strengthened as in the fifth embodiment.

FIG. 4 (4A) is a cross-sectional view of a rotor for explaining a seventh embodiment of the rotor of the present invention. The description of the same part as FIG. 3 (3A) is omitted. 4 (4A) is different from FIG. 3 (3A) in that a plurality of magnets are inserted into a concentric virtual arc having a constant width with the center of the rotor core 52 as a center on the inner peripheral side of the conductor bar 3. FIG. A plurality of rectangular (or square) permanent magnets 55 mainly composed of rare earth (or ferrite) embedded in the holes 54 are arranged so that the number of magnetic poles is two, and the four intermediate bars of the conductor bar 3 are rotated. A radial line connecting the child centers and a radial center line of a plurality of individual rectangular (or square) permanent magnets 55 are arranged so as to substantially coincide with each other, and the ratio of the number of magnets to the number between conductor bars is 1: 3 is one magnetic pole.
Even if configured in this way, the same effect as in FIG. 3 (3A) can be obtained, and the number of magnets constituting the magnetic pole is reduced, so that the number of production processes is shortened and the structure is simple, so that it is inexpensive. A permanent magnet synchronous motor can be provided.

  Embodiment 8 of the rotor of the present invention will be described with reference to FIG. 4 (4B). In FIG. 5 (5B), a rare earth (or ferrite) embedded in a plurality of magnet insertion holes 54 in a concentric virtual arc having a constant width centered on the center of the rotor core 52b on the inner peripheral side of the conductor bar 3. Are arranged such that the number of magnetic poles is two, the radius line connecting the middle of the conductor bar 3 and the center of the rotor, and a plurality of individual trapezoidal permanent magnets 5b. The number of magnets is 1: 3, and the number of magnets is 1: 3 to form one magnetic pole. Two connecting yokes 56b and 57b are provided between trapezoidal magnets constituting one magnetic pole. The effect similar to that of FIG. 4 (4B) can be obtained, and at the same time, the number of magnetic poles can be reduced, so that the number of production steps can be shortened and an inexpensive permanent magnet synchronous motor can be provided.

  FIG. 5 is an axial sectional view of a compressor according to a ninth embodiment of the present invention. In FIG. 5, the compression mechanism portion is formed by meshing a spiral wrap 63 standing upright on the end plate 62 of the fixed scroll member 61 and a spiral wrap 66 standing upright on the end plate 65 of the orbiting scroll member 64. . Then, the orbiting scroll member 64 is rotated by the crankshaft 10 to perform a compression operation, and the refrigerant is sucked and compressed from the suction port 67 and discharged from the discharge port 68.

  The compressor assembled by press-fitting the crankshaft 10 into the inner diameter of the rotor 1 of the permanent magnet synchronous motor described in the first to eighth embodiments is connected to a refrigeration cycle and is often used as an air conditioner. ing.

It is sectional drawing of the rotor which shows Example 1 and 2 of this invention. It is sectional drawing of the rotor which shows Example 3 and 4 of this invention. It is sectional drawing of the rotor which shows Example 5 and 6 of this invention. It is sectional drawing of the rotor which shows Example 7 and 8 of this invention. It is sectional drawing of Example 9 of the compressor of this invention. FIG. 3 is a diagram showing a magnetic flux density distribution on the rotor surface of Example 1. It is a figure which shows the magnetic flux density distribution of the rotor surface of a comparative example and Example 3. FIG. It is a figure which shows the magnetic flux of Example 3 of this invention. It is a figure which shows the magnetic flux of Example 1 of this invention. It is a figure which shows the shape at the time of manufacture of the permanent magnet of Example 2 of this invention. It is an enlarged view between the permanent magnets of Example 1 of this invention. FIG. 13 shows a comparative example with respect to Example 1 and corresponds to FIG. 12.

Explanation of symbols

DESCRIPTION OF SYMBOLS 10 ... Shaft, 2 ... Rotor core, 3 ... Conductor bar, 4 ... Magnet insertion hole, 5 ... Permanent magnet, 11 ... Stator, 10 ... Slot, 8・ ・ ・ Gap, 13 ... Center between adjacent permanent magnet centers, 901, 902 ... Conductor bar position, 903 ... Permanent magnet position, 904 ... Magnetic flux density of comparative example, 905 .. Magnetic flux density of Example 1, 1501... Permanent magnet, 1502... Gaps, 1503.

Claims (8)

  A suction port for sucking refrigerant; a compression mechanism for compressing the refrigerant sucked from the suction port; a discharge port for discharging the refrigerant compressed by the compression mechanism; and a permanent magnet synchronous motor for compressing the compression mechanism. In the compressor, the permanent magnet synchronous motor includes a plurality of slots, a stator having windings wound around the slots, and a rotor disposed inside the stator, and the rotor includes: It has a plurality of slots, a conductor bar is provided in the slot, a plurality of permanent magnets per one magnetic pole are arranged inside the conductor bar, and other than on the line connecting the center of the rotor and the center of the permanent magnet A compressor characterized in that the conductor bar is arranged only in a portion.   A stator having a plurality of slots and wound around the slots; and a rotor disposed inside the stator, the rotor having a plurality of slots, In a permanent magnet synchronous motor, comprising a conductor bar, wherein a plurality of permanent magnets are arranged per magnetic pole inside the conductor bar, the conductor is provided only on a portion other than a line connecting the center of the rotor and the center of the permanent magnet. A permanent magnet synchronous motor characterized by arranging a bar.   A suction port for sucking refrigerant; a compression mechanism for compressing the refrigerant sucked from the suction port; a discharge port for discharging the refrigerant compressed by the compression mechanism; and a permanent magnet synchronous motor for compressing the compression mechanism. In the compressor, the permanent magnet type synchronous motor includes a plurality of slots, a stator having windings wound around the slots, and a rotor disposed inside the stator, and the rotor Has a plurality of slots, a conductor bar is provided in the slot, a plurality of permanent magnets per magnetic pole are arranged inside the conductor bar, and the vicinity of a line connecting the center of the permanent magnet and the center of the rotor A compressor characterized in that a conductor bar disposed outside the permanent magnet is disposed only on the compressor.   2. The compressor according to claim 1, wherein the shape of the permanent magnet is a trapezoid in which the length of the outer peripheral side is longer than the length of the inner peripheral side.   2. The compressor according to claim 1, further comprising a convex yoke portion that supports the permanent magnet in the circumferential direction between the adjacent permanent magnets.   The compressor according to claim 1, wherein a connecting yoke portion is provided between the adjacent permanent magnets.   2. The compressor according to claim 1, wherein a ratio between the number of the conductor bars and the number of the permanent magnets is 3: 1. The compressor according to claim 1, wherein the number of slots of the stator is 30, and the number of conductor bars is 22.

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