JP2017079502A - Magnet structure and motor using the same - Google Patents

Abstract

PROBLEM TO BE SOLVED: To prevent damage to a magnet when inserting a magnet structure into a slot of a rotor.SOLUTION: A magnet structure 10 according to the present invention comprises: a single magnet 20 which is a rare earth sintered magnet or the like; and a non-magnetic case 30, covering the surface of the magnet 20, which is made of PET resin or the like. Because the surface of the magnet 20 is covered with the non-magnetic case 30, the present invention can prevent damage to the magnet 20 when inserting the magnet structure 10 into a slot of a rotor. In addition, unlike a structure in which a plurality of magnet pieces are collected, the present invention uses the single magnet. This avoids the difficulty in holding which may otherwise be caused when the magnet pieces repulse each other.SELECTED DRAWING: Figure 1

Description

  The present invention relates to a magnet structure and a motor using the same, and more particularly to a magnet structure suitable for use in an IPM type motor and a motor using the same.

  In recent years, IPM (Interior Permanent Magnet) type motors have been widely used as generator motors. The IPM type motor is also widely used as a motor for electric vehicles and hybrid cars.

  The IPM type motor includes a rotor formed with a plurality of slots, and a magnet is inserted into each slot (see Patent Document 1).

JP 2011-078268 A

  However, since the magnet used in the IPM type motor is easily damaged, the magnet surface may be damaged when the magnet is inserted into the rotor slot, or the magnet may be cracked or chipped. In particular, large-sized magnets are often used for motors for wind power generators. When a magnet is inserted into a slot, the magnet strongly sticks to the inner wall of the slot. It was not easy to insert into.

  Accordingly, an object of the present invention is to provide a magnet structure capable of preventing breakage of a magnet when inserted into a slot of a rotor, and a motor using the magnet structure.

  A magnet structure according to the present invention includes a single magnet and a nonmagnetic case that covers the surface of the magnet. A motor according to the present invention is a motor including a rotor having a plurality of slots formed therein, and the magnet structure is inserted into each of the plurality of slots.

  According to the present invention, since the surface of the magnet is covered with the nonmagnetic case, the magnet can be prevented from being damaged when inserted into the slot of the rotor.

  In the present invention, the surface of the magnet has first and second main surfaces having the largest areas facing each other, and the nonmagnetic case includes at least a part of the first main surface and the second main surface. It is preferable to cover at least part of the main surface. According to this, since the main surface is not in direct contact with the inner wall of the slot when inserted into the slot of the rotor, breakage of the magnet can be effectively prevented. Typically, the first and second main surfaces are the pole faces of the magnet.

  In the present invention, the nonmagnetic case has a cylindrical shape, whereby the nonmagnetic case is perpendicular to the first and second main surfaces of the magnet and the first and second main surfaces. Preferably, the first and second side surfaces of the magnet facing each other are continuously covered. According to this, it becomes possible to easily attach the nonmagnetic case to the magnet.

  The magnet structure according to the present invention includes first and second main surfaces and first and second sides of the magnet that are perpendicular to the first and second side surfaces and face each other. And a second nonmagnetic guide. This facilitates insertion into the slot.

  In the present invention, the first nonmagnetic guide further covers portions of the first and second side surfaces close to the third side surface, and the second nonmagnetic guide includes the first and second side surfaces. It is preferable to further cover the second side surface and a portion close to the fourth side surface. According to the present invention, it is possible to prevent the nonmagnetic guide from falling off after being inserted into the slot.

  In the present invention, the first and second nonmagnetic guides include an inner wall portion that covers any of the first to fourth side surfaces of the magnet, and an outer wall portion that faces the inner wall portion, It is preferable that the edge part located in the said 1st or 2nd side surface side of an outer wall part is notched in the taper shape. According to this, the insertion operation into the slot becomes even easier.

  In the present invention, a width of the first and second nonmagnetic guides in a direction perpendicular to the first and second side surfaces is longer than a distance between the first side surface and the second side surface. Thus, it is preferable to protrude from the first and second side surfaces. According to this, since a part of the nonmagnetic guide protrudes from the rotor in the state of being inserted into the slot, the air cooling effect can be increased.

  In the present invention, the magnet is preferably a rare earth sintered magnet, and the surface is preferably coated with a rust preventive coating. According to this, a stronger magnetic force can be obtained, and an antirust effect can be obtained.

  In the present invention, the nonmagnetic case is preferably made of a PET resin. According to this, it becomes possible to produce a magnet structure at low cost.

  ADVANTAGE OF THE INVENTION According to this invention, it becomes possible to provide the magnet structure which can prevent the damage of the magnet at the time of inserting in the slot of a rotor, and a motor using the same.

FIG. 1 is a perspective view showing an appearance of a magnet structure 10 according to a preferred embodiment of the present invention. FIG. 2 is an exploded perspective view of the magnet structure 10. 3A is a cross-sectional view taken along line AA shown in FIG. 1, and FIG. 3B is a cross-sectional view taken along line BB shown in FIG. FIG. 4A shows the appearance of the nonmagnetic case 30 according to the first modification, and FIG. 4B shows the appearance of the nonmagnetic case 30 according to the second modification. FIG. 5 is a side view of an IPM type motor 50 using the above-described magnet structure 10 as seen from the direction of the rotation axis. FIG. 6 is a view for explaining a method of inserting the magnet structure 10 into the slot 54. FIG. 7 is a plan view of the slot 54 in which the magnet structure 10 is inserted as viewed from the direction of the rotation axis. FIG. 8 is a cross-sectional view showing a state where the magnet structure 10 is inserted into the slot 54. FIG. 9 is a diagram for explaining a state in which a plurality of rotors 53 are connected. FIG. 10 is a diagram for explaining the state of the magnet structure 10 inserted into the plurality of rotors 53.

  Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the accompanying drawings.

  FIG. 1 is a perspective view showing an appearance of a magnet structure 10 according to a preferred embodiment of the present invention. 2 is an exploded perspective view of the magnet structure 10, FIG. 3A is a cross-sectional view taken along line AA shown in FIG. 1, and FIG. 3B is a cross-sectional view taken along line B- shown in FIG. It is sectional drawing along a B line.

  As shown in FIGS. 1 to 3, the magnet structure 10 according to the present embodiment includes a magnet 20 having a rectangular parallelepiped shape, a cylindrical nonmagnetic case 30 wound around the magnet 20, and the length direction of the magnet 20. First and second nonmagnetic guides 41 and 42 attached to both ends in the (y direction) are provided.

  The magnet 20 has a rectangular parallelepiped shape in which the x direction is the width direction, the y direction is the length direction, and the z direction is the thickness direction. Although the size is not particularly limited, the width in the x direction is 30 to 150 mm (for example, 50 mm), the length in the y direction is 50 to 150 mm (for example, 100 mm), and the thickness in the z direction is about 8 to 30 mm (for example, 10 mm). The above size is assumed to be used for a motor for a wind power generator. However, it is not essential that the magnet 20 has a rectangular parallelepiped shape. For example, the side surfaces 23 and 24 may be curved.

  The type of the magnet 20 is not particularly limited, but is preferably a rare earth sintered magnet, particularly an RTB-based sintered magnet. This is because a stronger magnetic force is required when used for a motor for a wind power generator. When the magnet 20 is a rare earth sintered magnet, the surface thereof is preferably rust-proof coated with a resin or the like.

  When the magnet structure 10 is used for a motor for a wind power generator, the wind power generator is generally often installed on the ocean or coastal areas where wind power is strong, and the magnet 20 is likely to deteriorate due to salt. For this reason, it is indispensable to apply a rust-proof coat to the surface of the magnet 20. In addition to resin, plating can be used as the rust-proof coating, but the magnet 20 used in the motor for wind power generators is large in size and difficult to plate. Resin coat) is preferred.

  In addition, a rust-proof coat made of a resin or the like generally has a low hardness, and particularly a resin coat has a low hardness. Therefore, it is difficult to prevent scratches and breakage of the resin-coated magnet 20, and in particular, it is difficult to prevent scratches and breakage that occur when inserted into the rotor slot. The magnet structure 10 according to the present embodiment includes the non-magnetic case 30 so that even when the magnet 20 is provided with a resin coating having low hardness, the rotor can be easily inserted into the slot, Scratches and damage that occur during insertion can be effectively prevented.

  The magnet 20 used in the present embodiment is a single magnet. A single magnet means a set of magnets that are not a collection of a plurality of magnet pieces. For this reason, unlike the case where a plurality of magnet pieces are assembled, the magnet pieces do not repel each other and are difficult to hold. Of the surfaces of the magnet 20, the two main surfaces 20N and 20S having the largest area are constituted by xy planes. Although not particularly limited, in the present embodiment, the main surfaces 20N and 20S are magnetic pole surfaces. Main surface 20 </ b> N constitutes the north pole of magnet 20, and main surface 20 </ b> S constitutes the south pole of magnet 20. As will be described later, the nonmagnetic case 30 covering the magnet 20 is a very thin film-like member. Therefore, when a plurality of magnetized magnet pieces are assembled, the repulsive force is reduced by the nonmagnetic case 30. It is difficult to suppress.

  The nonmagnetic case 30 is a thin cylindrical body, and is inserted in the y direction with respect to the magnet 20 so that the main surfaces 20N and 20S of the magnet 20 and the first and second side surfaces 21 and 22 that are yz planes are formed. Most of them are continuously covered by the nonmagnetic case 30. Nonmagnetic case 30 preferably covers as large an area of main surfaces 20N and 20S as possible. In the present embodiment, the nonmagnetic case 30 is constituted by a film having a continuous surface, and has a sufficient length in the y direction. Thereby, peeling of a rust preventive coat at the time of inserting in a slot, and a crack and breakage of magnet 20 itself can be prevented effectively. If the length of the nonmagnetic case 30 in the y direction is short, the mounting position of the nonmagnetic case 30 may be biased to one side in the y direction. In this case, the main surfaces 20N, 20S not covered by the nonmagnetic case 30 There is a risk of damaging the surface.

  However, the nonmagnetic case 30 does not need to have a continuous surface as long as scratches and breakage during insertion into the slot can be prevented, and may have various shapes. For example, a plurality of openings 31 may be provided on the surface of the nonmagnetic case 30 as shown in FIG. 4A, and the nonmagnetic case 30 itself is meshed as shown in FIG. It may be in the shape. When the nonmagnetic case 30 has the shape shown in FIGS. 4A and 4B, an effect of improving heat dissipation can be obtained.

  The material of the nonmagnetic case 30 is not particularly limited as long as it is a thin and non-breakable nonmagnetic material. As a material of the nonmagnetic case 30, it is preferable to use a film-like resin, paper, or the like, and it is particularly preferable to use a PET resin. The thickness of the nonmagnetic case 30 is not particularly limited, but is preferably a thickness that is slightly thinner than the gap between the magnet structure 10 and the inner wall of the slot. Specifically, if the gap between the magnet structure 10 and the inner wall of the slot is, for example, 0.2 mm, the thickness of the nonmagnetic case 30 may be about 0.188 mm. The reason why the non-magnetic case 30 is required to be thin is to effectively utilize the space and obtain high magnetic characteristics by reducing the gap between the magnet structure 10 and the inner wall of the slot as much as possible.

  Moreover, since the magnet structure 10 becomes high temperature (for example, 100 degreeC) when the motor for wind power generators rotates, it is preferable to use the material whose heat resistance is 150 degreeC or more, especially 200 degreeC or more. Although a metal can be selected as the material of the nonmagnetic case 30, a thin film-like metal (for example, a foil-like aluminum) is easily broken. On the contrary, if a thick metal is used, the magnet structure 10 is heavy. And the choice of metal is not always appropriate because of the increased gap.

  On the other hand, if PET resin is used as the material of the nonmagnetic case 30, the nonmagnetic case 30 can be manufactured very cheaply and easily, and sufficient tensile strength is ensured even in a thin film form. Can do. When PET resin is used as the material of the nonmagnetic case 30, it can be produced by cutting a film-like PET sheet into a predetermined size, forming it into a cylindrical shape, and ultrasonically welding the overlapping portions. . In this case, since the thickness is slightly increased at the bonded portion, adjustment may be made so that the bonded portion is positioned on the side surface 21 or 22 of the magnet 20. According to this, the thickness of the nonmagnetic case 30 covering the main surfaces 20N and 20S of the magnet 20 can be made constant, and the gap between the main surfaces 20N and 20S and the inner wall of the slot can be reduced.

  In addition, when a cylindrical PET resin is used as the nonmagnetic case 30, the magnet 20 and the nonmagnetic case 30 are not adhered, so even if a strong stress is applied to the nonmagnetic case 30 when inserted into the slot, Since the nonmagnetic case 30 can move freely, it is less likely to be broken.

  The nonmagnetic guide 41 is substantially C-shaped. That is, it has a rod-shaped portion extending in the x direction and protrusions provided at both ends of the rod-shaped portion in the x direction and bent in the y direction. The rod-shaped portion of the nonmagnetic guide 41 covers substantially the entire third side surface 23 that is the xz plane of the magnet 20. Further, the protruding portion of the nonmagnetic guide 41 covers the first and second side surfaces 21 and 22 of the magnet 20 and a portion close to the third side surface 23. Similarly, the nonmagnetic guide 42 is substantially C-shaped, covers almost the entire surface of the fourth side surface 24 that is the xz plane of the magnet 20 with the rod-shaped portion, and the first and second side surfaces of the magnet 20 with the protruding portion. 21 and 22, which cover portions close to the fourth side surface 24. Thereby, when inserting the magnet structure 10 in a slot, the 3rd and 4th side surfaces 23 and 24 of the magnet 20 do not contact | connect the inner wall of a slot, and a crack and damage are prevented. The nonmagnetic guides 41 and 42 can be fixed to the magnet 20 using an adhesive or the like.

  The width of the nonmagnetic guides 41 and 42 in the x direction is larger than the width of the magnet 20 in the x direction, and also serves to prevent the nonmagnetic case 30 wound around the magnet 20 from falling off. And when the part which covers either of the side surfaces 21-24 of the magnet 20 among the side surfaces along the z direction of the nonmagnetic guides 41 and 42 is an inner wall part, and the part which opposes this is an outer wall part, The corner portions, that is, both end portions in the x direction of the outer wall portion constitute a tapered portion 43 cut out in a tapered shape. As will be described later, the tapered portion 43 serves to facilitate insertion of the magnet structure 10 into the slot.

  The thickness of the nonmagnetic guides 41 and 42 in the z direction is the same as or slightly thinner than the thickness of the magnet 20 in the z direction, and at least does not protrude from the main surfaces 20N and 20S of the magnet 20. The material of the nonmagnetic guides 41 and 42 is not particularly limited as long as it is a hard nonmagnetic material, but aluminum (Al) or stainless steel is preferably used, and aluminum (Al) is particularly preferably used. If aluminum (Al) is used as the material of the nonmagnetic guides 41 and 42, sufficient mechanical strength can be ensured at low cost, and high heat dissipation can be obtained.

  The length of the nonmagnetic guides 41 and 42 in the y direction is preferably about 2 mm to 6 mm, and more preferably about 3 mm. The lengths of the nonmagnetic guides 41 and 42 in the y direction serve to secure a gap in the y direction between the inner wall of the slot and the magnet 20 when the magnet structure 10 is inserted into the slot. By ensuring the thickness, a short circuit of the magnetic flux can be prevented. Moreover, the heat dissipation effect is enhanced by securing the volume of the nonmagnetic guides 41 and 42 to some extent.

  The nonmagnetic guides 41 and 42 may be integrated to form a ring shape that surrounds the side surfaces 21 to 24 of the magnet 20. However, in this case, the weight and cost increase and a space 44 described later is not formed. Air cooling effect is reduced. For this reason, it is preferable to attach the nonmagnetic guides 41 and 42 to the third and fourth side surfaces 23 and 24, respectively, as in this embodiment.

  FIG. 5 is a side view of an IPM type motor 50 using the above-described magnet structure 10 as seen from the direction of the rotation axis.

  A motor 50 shown in FIG. 5 includes a cylindrical stator 52 in which a plurality of coils 51 are arranged in a ring shape, and a disk-like rotor 53 inserted into the inner diameter portion of the stator 52. The rotor 53 is made of a silicon steel plate having a high magnetic permeability. The rotor 53 is provided with a plurality of slots 54 into which the above-described magnet structures 10 are respectively inserted. And if the rotating shaft of the rotor 53 is connected to the rotating shaft of a windmill, for example, an electric current will flow into the coil 51 by rotation of the rotor 53, and a wind power generator is comprised by this. However, the application of the motor 50 is not limited to the wind power generator, and the motor 50 may be used for other power generators. Conversely, the rotor 53 may be rotated by passing a current through the coil 51. Absent.

  The slot 54 has a long side 54y and a short side 54z. The long side 54y is slightly larger than the length of the magnet structure 10 in the y direction, and the short side 54z is slightly larger than the thickness of the magnet structure 10 in the z direction. large. When the magnet structure 10 is inserted into the slot 54 in a state where the y direction of the magnet structure 10 is aligned with the long side 54y and the z direction of the magnet structure 10 is aligned with the short side 54z, a magnet is inserted into the slot 54. The structure 10 is accommodated.

  FIG. 6 is a view for explaining a method of inserting the magnet structure 10 into the slot 54, and represents an xy section of the rotor 53.

  As shown in FIG. 6, the magnet structure 10 is inserted into the slot 54 provided in the rotor 53 in the x direction. The thickness of the rotor 53 in the x direction is substantially the same as the width of the magnet 20 in the x direction. When the magnet structure 10 is inserted into the slot 54, the nonmagnetic guides 41 and 42 play a role of positioning in the y direction. Further, since the nonmagnetic guides 41 and 42 are provided with the tapered portion 43, the magnet structure 10 can be smoothly inserted into the slot 54.

  Further, when the magnet structure 10 is inserted into the slot 54, the magnet 20 is magnetized, so that it strongly adheres to the inner wall of the slot 54 made of a silicon steel plate. For this reason, it is necessary to push the magnet structure 10 in the x direction with a relatively strong force. At this time, if the main surface 20N or 20S of the magnet 20 is not covered with the nonmagnetic case 30, the main surface 20N or 20S is in direct contact with the inner wall of the slot 54 and is pushed in the x direction in this state. 20N or 20S has a strong friction, and the rust-proof coat may be peeled off, or the magnet 20 may be scratched or damaged.

  However, in the magnet structure 10 according to the present embodiment, since most of the main surfaces 20N and 20S are covered with the nonmagnetic case 30, the rotor 53 is shown in FIG. 7 as viewed from the rotation axis direction (x direction). As shown, the magnet structure 10 can be pushed in with the nonmagnetic case 30 interposed. Thereby, the generation | occurrence | production of the damage | wound and damage to the magnet 20 at the time of insertion is prevented reliably.

  FIG. 8 is a view showing a state in which the magnet structure 10 is inserted into the slot 54, and shows an xy cross section of the rotor 53.

  As shown in FIG. 8, when the magnet structure 10 is completely inserted into the slot 54, a part of the nonmagnetic guides 41 and 42 protrudes from the rotor 53. Thereby, when the rotor 53 rotates, the heat generated by the magnet structure 10 is efficiently released through the nonmagnetic guides 41 and 42. Further, since the nonmagnetic guides 41 and 42 have a C-shape having a rod-like portion and projecting portions provided at both ends thereof, the nonmagnetic guide 41 is inserted after the magnet structure 10 is inserted into the slot 54. , 42 does not fall out of the slot 54 even if it is detached from the magnet 20.

  FIG. 9 is a view for explaining a state in which a plurality of rotors 53 are connected, and is a side view seen from a direction perpendicular to the rotation axis. In consideration of the visibility of the drawing, FIG. 9 shows a state in which the magnet structure 10 is not inserted into the slot 54.

  As shown in FIG. 9, if a plurality of rotors 53 are connected so that the rotation axes coincide with each other, rotation with larger torque can be converted into electric power. Such a method of use is suitable for a wind power generator or the like. When a plurality of rotors 53 are connected and used in this way, it is preferable that the positions of the slots 54 viewed from the direction of the rotation axis coincide with each other. If the slot 54 is arranged in this way and the interval P between the adjacent rotors 53 is set to be twice the protruding amount of the nonmagnetic guides 41 and 42, the slot 54 has a slot as shown in FIG. When the magnet structure 10 is inserted, the protruding portions of the nonmagnetic guides 41 and 42 come into contact with each other in the adjacent magnet structure 10. Thereby, since adjacent magnet structure 10 will be in the state which supports each other, the vibration of the magnet structure 10 at the time of rotation, etc. are suppressed.

  In addition, since the nonmagnetic guides 41 and 42 protrude only at both ends in the y direction, a space 44 shown in FIG. 10 is formed between the pair of protrusions. This space 44 functions as a heat dissipation route and exhibits a high air cooling effect.

  As described above, according to the present embodiment, since the magnet structure 10 includes the nonmagnetic case 30, it is possible to prevent the magnet 20 from being scratched or damaged when inserted into the slot 54. In addition, since the nonmagnetic guides 41 and 42 are provided, insertion into the slot 54 is facilitated and a high heat dissipation effect can be obtained. Due to these features, the magnet structure 10 according to the present embodiment is particularly suitable for application to a motor for a wind power generator.

  The preferred embodiments of the present invention have been described above, but the present invention is not limited to the above-described embodiments, and various modifications can be made without departing from the spirit of the present invention. Needless to say, it is included in the range.

DESCRIPTION OF SYMBOLS 10 Magnet structure 20 Magnet 20N 1st main surface 20S 2nd main surface 21 1st side surface 22 2nd side surface 23 3rd side surface 24 4th side surface 30 Nonmagnetic case 31 Opening part 41 1st non-surface Magnetic guide 42 Second nonmagnetic guide 43 Tapered portion 44 Space 50 Motor 51 Coil 52 Stator 53 Rotor 54 Slot 54y Slot long side 54z Slot short side P Spacing

Claims (11)

With a single magnet,
A magnet structure comprising: a nonmagnetic case that covers a surface of the magnet. The surface of the magnet has first and second main surfaces having the largest areas facing each other,
The magnet structure according to claim 1, wherein the nonmagnetic case covers at least a part of the first main surface and at least a part of the second main surface.   The magnet structure according to claim 2, wherein the first and second main surfaces are magnetic pole surfaces of the magnet.   The nonmagnetic case has a cylindrical shape, whereby the nonmagnetic case is perpendicular to the first and second main surfaces of the magnet and perpendicular to the first and second main surfaces. The magnet structure according to claim 2 or 3, wherein the magnet structure covers the first and second side surfaces of the magnet continuously.   First and second nonmagnetic guides covering the first and second main surfaces and the third and fourth side surfaces of the magnet that are perpendicular to the first and second side surfaces and face each other, respectively. The magnet structure according to claim 4, further comprising: The first nonmagnetic guide further covers a portion of the first and second side surfaces close to the third side surface,
The magnet structure according to claim 5, wherein the second nonmagnetic guide further covers portions of the first and second side surfaces that are close to the fourth side surface. The first and second nonmagnetic guides have an inner wall portion that covers any of the first to fourth side surfaces of the magnet, and an outer wall portion that faces the inner wall portion,
The magnet structure according to claim 5 or 6, wherein an end portion of the outer wall portion located on the first or second side face is notched in a tapered shape.   The width of the first and second nonmagnetic guides in the direction perpendicular to the first and second side surfaces is longer than the distance between the first side surface and the second side surface, thereby The magnet structure according to claim 5, wherein the magnet structure protrudes from the first and second side surfaces.   The magnet structure according to any one of claims 1 to 8, wherein the magnet is a rare earth sintered magnet, and the surface is coated with a rust-proof coating.   The magnet structure according to claim 1, wherein the nonmagnetic case is made of PET resin.   A motor comprising a rotor formed with a plurality of slots, wherein the magnet structure according to any one of claims 1 to 10 is inserted into each of the plurality of slots.

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