JP2011166952A - Permanent magnet rotary machine - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a permanent magnet rotary machine capable of reducing loss by reducing an eddy current flowing through a scatter preventing device. <P>SOLUTION: The permanent magnet rotary machine includes: a stator 3 which has a coil wound therearound; and a rotor 4 which has a rotor core 21 opposing the stator, permanent magnets 22 which are adjacent in a circumferential direction and have different magnetic polarities on a surface where the rotor core and the stator oppose to each other and a scatter preventing member 23 for covering the surface where the permanent magnets oppose the stator, and rotates oppositely to the stator with a predetermined gap. The scatter preventing member 23 has an opened window 26 for exposing at least some of the permanent magnets 22 to the outside. <P>COPYRIGHT: (C)2011,JPO&INPIT

Description

  The present invention relates to a permanent magnet type rotating machine including a stator and a rotor having a rotor core having a predetermined gap and rotating oppositely and having a permanent magnet disposed on a surface thereof.

In recent years, in order to increase the efficiency of electric motors, permanent magnet type synchronous motors using permanent magnets have attracted attention in place of conventionally used induction motors, and their applications are expanding.
Permanent magnet type synchronous motors are roughly classified into two types according to the magnet arrangement. A permanent magnet type synchronous motor having a structure in which a permanent magnet is attached to the surface of the rotor core and a magnet insertion hole in the rotor core are provided. There is an embedded magnet type synchronous motor into which a magnet is inserted.

In a surface magnet type synchronous motor, normally, a permanent magnet is adhered and fixed to the surface of a rotor core with an adhesive. However, when the rotor is rotated at a high speed, the centrifugal force applied to the permanent magnet is increased accordingly, and the permanent magnet may be peeled off and scattered from the rotor core.
For this reason, normally, a cylindrical carbon ring made of carbon fiber reinforced plastic is press-fitted into the outer peripheral surface of the permanent magnet as a means for preventing scattering (for example, see Patent Document 1).
Further, on the outer peripheral surface of the permanent magnet of the rotor, the relative magnetic permeability is 100 or more at a magnetic flux density of 0.5 to 0.8 (T), and the relative magnetic permeability is at or above 1.6 (T). It has also been proposed to arrange a retaining ring formed of a non-magnetic material of SUS630 having a value of 10 (see, for example, Patent Document 2).

JP 2005-312250 A JP-A-7-107719

However, in the conventional example described in Patent Document 1, a carbon ring is used, and this carbon ring is light but expensive and has a problem of increasing manufacturing cost. Moreover, in the conventional example described in the cited reference 1 or 2, in any case, the entire outer peripheral surface of the permanent magnet is covered with a carbon ring or a stainless steel retaining ring. Since the ring is composed of a cylindrical body as shown in FIG. 6, the magnetic flux passing through the cylindrical body changes, and an eddy current flows in the direction of weakening the magnetic flux as shown by an annular arrow A in FIG. , There is an unresolved problem that loss occurs. This eddy current is determined by the conductivity of the cylindrical body. When the entire rotor is covered with a ring as in the conventional examples described in Patent Documents 1 and 2, the eddy current is vortexed in an arbitrary path according to the conductivity of the ring. There is a problem that current flows.
Therefore, the present invention has been made paying attention to the above-mentioned unsolved problems of the conventional example, and provides a permanent magnet type rotating machine capable of reducing loss by reducing eddy current flowing in the scattering prevention means. The purpose is that.

  In order to achieve the above object, a permanent magnet type rotating machine according to one aspect of the present invention includes a stator wound with a coil, a rotor core facing the stator, and the rotor core. A permanent magnet having a different polarity circumferentially adjacent to a surface facing the stator, and a scattering prevention member covering the surface facing the stator of the permanent magnet, and separating the stator from a predetermined gap The anti-scattering member includes an open window that exposes at least a part of the permanent magnet to the outside. .

Further, in the permanent magnet type rotating machine according to another aspect of the present invention, the scattering prevention member includes a pair of annular belt portions covering both axial end portions of the permanent magnet, and the pair of annular belt portions. Is formed of a connecting band portion that is connected at a predetermined interval so as to form the open window portion.
Furthermore, the permanent magnet type rotating machine according to another aspect of the present invention is characterized in that the connecting band portion is arranged so that two connecting band portions are in contact with one permanent magnet. Yes.

  According to the present invention, since the open window portion is formed in the anti-scattering member that prevents the permanent magnets of the rotor from scattering, the eddy current flows around the open window portion, and the path of the eddy current is limited. In addition, since the conductivity is lower than when there is no open window, eddy current can be reduced, and loss generated in the scattering prevention member can be reduced. Therefore, it is possible to provide a permanent magnet type synchronous motor that can achieve high efficiency.

It is sectional drawing which shows the permanent-magnet-type synchronous rotary machine manufactured by this invention. It is a perspective view which shows the rotor with which the scattering prevention member by this invention was mounted | worn. It is a perspective view of the scattering prevention member of FIG. It is a perspective view of the rotor which shows the other example of a scattering prevention member. It is a perspective view of the rotor which shows the further another example of a scattering prevention member. It is a perspective view which shows the conventional scattering prevention member.

Hereinafter, embodiments of the present invention will be described with reference to the drawings.
FIG. 1 is a sectional view showing a permanent magnet type synchronous rotating machine manufactured according to a first embodiment of the present invention.
In FIG. 1, a permanent magnet type synchronous rotating machine 1 is a surface magnet type synchronous rotating machine. This permanent magnet type synchronous rotating machine 1 has a cylindrical frame 2. A stator 3 formed of a cylindrical laminated steel plate is fixed on the inner peripheral side of the cylindrical frame 2, and formed on the inner peripheral side of the stator 3 by a laminated steel plate facing each other with a predetermined gap. A rotor 4 is arranged. The rotor 4 is rotatably supported by a bearing (not shown) formed on the cylindrical frame 2 with a rotating shaft 5 inserted through the center.

The stator 3 has a configuration in which a stator core 11 that is divided into nine in the circumferential direction is connected to the inner circumferential side of the cylindrical frame 2 in a circumferential direction. Each stator core 11 has nine yokes 12 whose outer peripheral surface is formed into a cylindrical surface and whose inner peripheral surface is a nine-sided cylinder inner surface, and a radius from the center in the circumferential direction of the inner peripheral surface of the yoke 12. The magnetic pole teeth 13 are formed to project in the direction.
The magnetic pole teeth 13 are composed of a magnetic leg portion 13a having a constant width Tw connected to the yoke 12, and a wedge-shaped flange portion 13b protruding in the circumferential direction from the tip of the magnetic leg portion 13a.
Nine slots 14 are formed by the yoke 12 and the magnetic teeth 13 of the adjacent stator core 11, and a slot opening 15 is formed between the flanges 13 b of the adjacent magnetic teeth 13.
An excitation coil 16 is concentratedly wound around the magnetic leg portion 13 a of the magnetic pole tooth 13.

On the other hand, as shown in FIG. 2, the rotor 4 has a cylindrical rotor core 21 having a central opening 21 a through which the rotary shaft 5 is inserted, and a predetermined gap in the circumferential direction on the outer peripheral surface of the rotary core 21. For example, eight permanent magnets 22 that are bonded and fixed by an adhesive and extend in the axial direction, and a scattering prevention member 23 that holds the outer peripheral surface of the permanent magnets 22 and prevents the permanent magnets from scattering. It is configured.
Here, the permanent magnet 22 is formed, for example, in the shape of a cross-sectional fan by forming a rare earth magnet with a cylindrical surface having an inner peripheral surface and an outer peripheral surface coaxial.

  Further, as shown in FIG. 3, the anti-scattering member 23 is made of a nonmagnetic material such as SUS304 or Inconel, and a pair of circles that hold both ends in the axial direction of the permanent magnets 22 arranged circumferentially. Annular belt-like plate portions 24 and 25, and a connecting belt-like shape arranged between the belt-like plate portions 24 and 25 so as to extend in the axial direction and form an open window portion 26 with a predetermined interval in the circumferential direction. The plate portion 27 is formed into a bowl shape. Here, the circumferential interval between the connecting plate portions 27 is set so that the two connecting strip-shaped plate portions 27 are in contact with one permanent magnet 22.

Thus, according to the above embodiment, since the permanent magnet type synchronous rotating machine 1 has the configuration of a surface permanent magnet type rotating machine, the circumferential central portion of the permanent magnet 22 of the rotor 4 is adjacent to the d axis. The rotor 4 can be driven to rotate by setting the q axis between the permanent magnets 22 and energizing the exciting coil 16 to control the dq axis current.
At this time, since the outer peripheral surface of the permanent magnet 22 bonded and fixed to the outer peripheral surface of the rotor core 21 of the rotor 4 is held by the scattering prevention member 23, the rotor 4 is driven to rotate at a high speed and the permanent magnet 22. Even if a large centrifugal force acts on the permanent magnet 22 and the permanent magnet 22 is about to peel off, the permanent magnet 22 can be reliably prevented from being scattered by being held by the scattering prevention member 23. At this time, since the two connecting strip-shaped plate portions 27 are in contact with each other in the circumferential direction of the single permanent magnet 22, the permanent magnet 22 can be reliably held by the two connecting strip-shaped plate portions 27.

  And since the scattering prevention member 23 is formed with an open window portion 26 by a pair of annular belt-like plate portions 24 and 25 and a connecting belt-like plate portion 27 that connects them, the rotor 4 is When an eddy current is generated by a change in magnetic flux between the magnetic pole teeth 13 of the stator and the permanent magnet 22 of the rotor 4 that is generated when the rotor is driven to rotate, the eddy current is generated as shown in FIG. The peripheral band plates 24 and 25 and the two connecting band plates 27 are formed to limit the path of the eddy current, and the scattering prevention member 23 does not form the open window 26. Since the conductivity is lower than that in the case of forming the eddy current, eddy current can be reduced. Therefore, it is possible to reduce the loss generated in the scattering prevention member 23, and it is possible to provide a permanent magnet type synchronous motor that can realize high efficiency. Moreover, since the anti-scattering member 23 is made of a non-magnetic material such as SUS304 or Inconel, it can be manufactured at a lower cost than the carbon ring in the cited reference 1 described above, and the open window portion 26 is formed. Therefore, the weight can be reduced.

In addition, in the said embodiment, although the case where the one permanent magnet 22 was hold | maintained with the two connection strip | belt-shaped board parts 27 was demonstrated, it is not limited to this, The connection strip | belt-shaped board part holding the permanent magnet 22 is demonstrated. The number of 27 can be arbitrarily set according to the holding strength.
Moreover, although the case where the cross-sectional shape of the permanent magnet 22 is a fan shape was demonstrated in the said embodiment, it is not limited to this, The thickness of the center part of the circumferential direction of the permanent magnet 22 is one. When it has a bowl shape that is thicker and gradually decreases in thickness from this central portion in the circumferential direction, as shown in FIG. 4, the connecting strip-shaped plate portion 27 is provided at the central portion in the circumferential direction of the permanent magnet 22. The connecting band-shaped plate portion 27 may be arranged so that the two come into contact with each other.

  Moreover, in the said embodiment, although the case where the scattering prevention member 23 was comprised with a pair of annular strip | belt-shaped plate parts 24 and 25 and the connection strip | belt-shaped plate part 27 was demonstrated, it is not limited to this, As shown in FIG. 5, a circumferential belt-like plate portion 28 that connects the central portions in the axial direction of the joint belt-like plate portion 27 may be disposed. In short, the permanent magnet 22 is externally attached to the scattering prevention member 23. If the desired open window portion 26 is formed, the periphery of the open window portion 26 can be used as an eddy current path, so that the effect of the present invention can be exhibited. For this reason, the shape of the open window portion 26 is not limited to a rectangular shape, and may be an arbitrary shape such as an elliptical shape or a circular shape.

  DESCRIPTION OF SYMBOLS 1 ... Permanent magnet type synchronous rotating machine, 2 ... Cylindrical frame, 3 ... Stator, 4 ... Rotor, 5 ... Rotating shaft, 11 ... Stator core, 12 ... Yoke, 13 ... Magnetic pole teeth, 14 ... Slot, 16 DESCRIPTION OF SYMBOLS ... Excitation coil, 21 ... Rotor core, 21a ... Center opening, 22 ... Permanent magnet, 23 ... Spattering prevention member, 24, 25 ... Ring-shaped strip | belt board part, 26 ... Opening window part, 27 ... Connecting strip | belt-shaped board part

Claims (3)

A stator around which a coil is wound, a rotor core facing the stator, permanent magnets of different polarities circumferentially adjacent to a surface of the rotor core facing the stator, the permanent A permanent magnet-type rotating machine having a scattering prevention member that covers a surface facing the stator of the magnet, and comprising the stator and a rotor that rotates to face and face a predetermined gap,
The anti-scattering member is provided with an open window that exposes at least part of the permanent magnet to the outside.   The scattering prevention member includes a pair of annular belt portions that cover both ends of the permanent magnet in the axial direction, and a connection that connects the pair of annular belt portions at a predetermined interval so as to form the open window portion. The permanent magnet type rotating machine according to claim 1, wherein the permanent magnet type rotating machine is constituted by a belt portion.   3. The permanent magnet type rotating machine according to claim 2, wherein the connection band portion is disposed so that two connection band portions are in contact with one permanent magnet. 4.

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