JP6992841B2 - Magnet structure and motor using it - Google Patents

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, an IPM (Interior Permanent Magnet) type motor has been widely used as a motor for a generator. IPM type motors are also widely used as motors for electric vehicles and hybrid cars.

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

Japanese Unexamined Patent Publication No. 2011-0728268

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

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

The magnet structure according to the present invention is characterized by comprising a single magnet and a non-magnetic case covering the surface of the magnet. Further, the motor according to the present invention is a motor including a rotor in which a plurality of slots are formed, and is characterized in that 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 a non-magnetic case, it is possible to prevent the magnet from being damaged when it is inserted into the slot of the rotor.

In the present invention, the surface of the magnet has the first and second main surfaces having the largest areas facing each other, and the non-magnetic case is at least a part of the first main surface and the second main surface. It is preferable to cover at least a part of the main surface. According to this, when the magnet is inserted into the slot of the rotor, the main surface does not come into direct contact with the inner wall of the slot, so that the magnet can be effectively prevented from being damaged. Typically, the first and second main surfaces are the magnetic pole surfaces of the magnet.

In the present invention, the non-magnetic case is cylindrical, whereby the non-magnetic case is perpendicular to the first and second main surfaces of the magnet and the first and second main surfaces. It is preferable to continuously cover the first and second side surfaces of the magnets facing each other. This makes it possible to easily attach the non-magnetic case to the magnet.

The magnet structure according to the present invention covers the first and second main surfaces and the third and fourth side surfaces of the magnet which are perpendicular to the first and second side surfaces and face each other, respectively. And it is preferable to further include a second non-magnetic guide. This facilitates the work of inserting into the slot.

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

In the present invention, the first and second non-magnetic 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. It is preferable that the end portion of the outer wall portion located on the first or second side surface side is notched in a tapered shape. According to this, the work of inserting into the slot becomes easier.

In the present invention, the width of the first and second non-magnetic 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. It is preferable that this projects from the first and second side surfaces. According to this, a part of the non-magnetic guide protrudes from the rotor when it is inserted into the slot, so that the air cooling effect can be increased.

In the present invention, the magnet is a rare earth sintered magnet, and it is preferable that the surface is rust-proof coated. According to this, a stronger magnetic force can be obtained and a rust preventive effect can be obtained.

In the present invention, it is preferable that the non-magnetic case is made of PET resin. This makes it possible to inexpensively manufacture the magnet structure.

According to the present invention, it is possible to provide a magnet structure capable of preventing damage to a magnet when it is inserted into a slot of a rotor, and a motor using the same.

FIG. 1 is a perspective view showing the appearance of the 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 the line AA shown in FIG. 1, and FIG. 3B is a cross-sectional view taken along the line BB shown in FIG. FIG. 4A shows the appearance of the non-magnetic case 30 according to the first modification, and FIG. 4B shows the appearance of the non-magnetic case 30 according to the second modification. FIG. 5 is a side view of the IPM type motor 50 using the above-mentioned magnet structure 10 as viewed from the direction of the axis of rotation. FIG. 6 is a diagram for explaining a method of inserting the magnet structure 10 into the slot 54. FIG. 7 is a plan view of the slot 54 into which the magnet structure 10 is inserted as viewed from the direction of the axis of rotation. FIG. 8 is a cross-sectional view showing a state in which 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 a 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 the appearance of the 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 the line AA shown in FIG. 1, and FIG. 3B is a B-shown in FIG. It is sectional drawing along the B line.

As shown in FIGS. 1 to 3, the magnet structure 10 according to the present embodiment has a magnet 20 having a rectangular parallelepiped shape, a tubular non-magnetic case 30 wound around the magnet 20, and the length direction of the magnet 20. It includes first and second non-magnetic guides 41 and 42 attached to both ends in the (y direction).

The magnet 20 has a rectangular parallelepiped shape with the x direction as the width direction, the y direction as the length direction, and the z direction as the thickness direction. The size is not particularly limited, but 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) is preferable. The above size is a size 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, and for example, the side surfaces 23 and 24 may be curved.

The type of the magnet 20 is not particularly limited, but a rare earth sintered magnet, particularly an RTB-based sintered magnet is preferable. This is because a stronger magnetic force is required when it is assumed to be used for a motor for a wind power generator. When the magnet 20 is a rare earth sintered magnet, it is preferable that the surface thereof is 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 installed in an offshore or coastal area where wind power is strong, and the magnet 20 is easily deteriorated by salt content. Therefore, it is indispensable to apply a rust preventive coat to the surface of the magnet 20. As the rust preventive coat, plating can be used in addition to the resin, but since the magnet 20 used for the motor for the wind power generator is large in size and it is difficult to apply the plating, the rust preventive coat with the resin ( Resin coating) is suitable.

Further, the rust preventive coat made of resin or the like generally has a low hardness, and the resin coat in particular has a low hardness. Therefore, it is difficult to prevent the magnet 20 coated with the resin from being scratched or damaged, and in particular, it is difficult to prevent the magnet 20 from being scratched or damaged when it is inserted into the slot of the rotor. By providing the non-magnetic case 30, the magnet structure 10 according to the present embodiment facilitates insertion of the rotor into the slot even when the magnet 20 is coated with a resin having a low hardness. It is possible to effectively prevent scratches and breakage that occur during insertion.

The magnet 20 used in this embodiment is a single magnet. A single magnet means a mass of magnets, not a collection of multiple magnet pieces. Therefore, unlike the case where a plurality of magnet pieces are assembled, the magnet pieces do not repel each other and it is not difficult to hold the magnet pieces. Of the surfaces of the magnet 20, the two main surfaces 20N and 20S having the largest area are composed of xy surfaces. Although not particularly limited, in the present embodiment, the main surfaces 20N and 20S are magnetic pole surfaces. The main surface 20N constitutes the north pole of the magnet 20, and the main surface 20S constitutes the south pole of the magnet 20. As will be described later, since the non-magnetic case 30 that covers the magnet 20 is a very thin film-like member, when a plurality of magnetized magnet pieces are assembled, the repulsive force is applied by the non-magnetic case 30. It is difficult to suppress.

The non-magnetic case 30 is a thin cylindrical body, and by inserting it in the y direction with respect to the magnet 20, the main surfaces 20N and 20S of the magnet 20 and the first and second side surfaces 21 and 22 which are yz planes are formed. Most are continuously covered by the non-magnetic case 30. The non-magnetic case 30 preferably covers as large an area as possible on the main surfaces 20N and 20S. In the present embodiment, the non-magnetic case 30 is composed of a film having a continuous surface, and has a sufficient length in the y direction. As a result, it is possible to effectively prevent the rust preventive coat from peeling off when the magnet 20 is inserted into the slot, and the magnet 20 itself from being scratched or damaged. If the length of the non-magnetic case 30 in the y direction is short, the mounting position of the non-magnetic case 30 may be biased to one side in the y direction. In this case, the main surfaces 20N, 20S not covered by the non-magnetic case 30. The surface of the surface may be damaged.

However, the non-magnetic case 30 does not have to have a continuous surface and may have various shapes as long as it can prevent scratches and breakage when it is inserted into the slot. For example, as shown in FIG. 4A, a plurality of openings 31 may be provided on the surface of the non-magnetic case 30, and as shown in FIG. 4B, the non-magnetic case 30 itself is a mesh. It may be in the form. When the non-magnetic case 30 has the shape shown in FIGS. 4 (a) and 4 (b), the effect of enhancing heat dissipation can be obtained.

The material of the non-magnetic case 30 is not particularly limited as long as it is a thin non-magnetic material that is not easily torn. As the material of the non-magnetic case 30, it is preferable to use a film-shaped resin, paper, or the like, and it is more preferable to use a PET resin. The thickness of the non-magnetic case 30 is not particularly limited, but is preferably a thickness 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 non-magnetic 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 making the gap between the magnet structure 10 and the inner wall of the slot as small as possible.

Further, in the motor for a wind power generator, since the magnet structure 10 becomes high temperature (for example, 100 ° C.) during rotation, it is preferable to use a material having a heat resistance of, for example, 150 ° C. or higher, particularly 200 ° C. or higher. Although it is possible to select a metal as the material of the non-magnetic case 30, a thin film-like metal (for example, foil-like aluminum) is easily torn, and conversely, if a thick metal is used, the magnet structure 10 becomes heavy. However, it is not always appropriate to select a metal because of the increased gap.

On the other hand, if PET resin is used as the material of the non-magnetic case 30, the non-magnetic case 30 can be manufactured very inexpensively and easily, and sufficient tensile strength is ensured even in the form of a thin film. Can be done. When PET resin is used as the material of the non-magnetic case 30, it can be produced by cutting a film-shaped PET sheet to a predetermined size, forming it into a cylindrical shape, and ultrasonically fusing the overlapping portions. .. In this case, since the thickness of the bonded portion is slightly increased, the bonded portion may be adjusted so as to be located on the side surface 21 or 22 of the magnet 20. According to this, the thickness of the non-magnetic case 30 that covers 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.

Further, when the tubular PET resin is used as the non-magnetic case 30, since the magnet 20 and the non-magnetic case 30 are not adhered to each other, even if a strong stress is applied to the non-magnetic case 30 when the non-magnetic case 30 is inserted into the slot. Since the non-magnetic case 30 can move freely, it is less likely to be torn.

The non-magnetic guide 41 is substantially C-shaped. That is, it has a rod-shaped portion extending in the x direction and protruding portions 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 non-magnetic guide 41 covers almost the entire surface of the third side surface 23, which is the xz surface of the magnet 20. Further, the protruding portion of the non-magnetic guide 41 covers the portions of the first and second side surfaces 21 and 22 of the magnet 20 near the third side surface 23. Similarly, the non-magnetic guide 42 is substantially C-shaped, and the rod-shaped portion covers almost the entire surface of the fourth side surface 24 which is the xz surface of the magnet 20, and the protruding portion covers the first and second side surfaces of the magnet 20. It is 21 and 22 and covers the portion close to the fourth side surface 24. As a result, when the magnet structure 10 is inserted into the slot, the third and fourth side surfaces 23 and 24 of the magnet 20 do not come into contact with the inner wall of the slot, and scratches and breakage are prevented. The non-magnetic guides 41 and 42 can be fixed to the magnet 20 by using an adhesive or the like.

The width of the non-magnetic 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 non-magnetic case 30 wound around the magnet 20 from falling off. When the portion of the non-magnetic guides 41 and 42 along the z direction that covers any of the side surfaces 21 to 24 of the magnet 20 is the inner wall portion and the portion facing the inner wall portion is the outer wall portion, the outer wall portion is used. The corner portions, that is, both ends of the outer wall portion in the x direction form a tapered portion 43 notched in a tapered shape. As will be described later, the tapered portion 43 serves to facilitate the insertion of the magnet structure 10 into the slot.

The thickness of the non-magnetic guides 41 and 42 in the z direction is equal to or slightly thinner than the thickness of the magnet 20 in the z direction, and at least has no protrusion with respect to the main surfaces 20N and 20S of the magnet 20. The material of the non-magnetic guides 41 and 42 is not particularly limited as long as it is a hard non-magnetic material, but it is preferable to use aluminum (Al) or stainless steel, and it is particularly preferable to use aluminum (Al). If aluminum (Al) is used as the material of the non-magnetic guides 41 and 42, sufficient mechanical strength can be secured at low cost, and high heat dissipation can be obtained.

The length of the non-magnetic guides 41 and 42 in the y direction is preferably about 2 mm to 6 mm, more preferably about 3 mm. The length of the non-magnetic guides 41 and 42 in the y direction plays a role of securing 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, and this gap is made to a certain length. By ensuring this, it is possible to prevent a short circuit of the magnetic flux. Further, the heat dissipation effect can be enhanced by securing a certain volume of the non-magnetic guides 41 and 42.

The non-magnetic guides 41 and 42 may be integrated into a ring shape surrounding the side surfaces 21 to 24 of the magnet 20, but in this case, the weight and cost increase and the space 44 described later is not formed. The air cooling effect is low. Therefore, it is preferable to attach the non-magnetic guides 41 and 42 to the third and fourth side surfaces 23 and 24, respectively, as in the present embodiment.

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

The 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-shaped 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, and the magnet structure 10 described above is inserted into each of the slots 54. Then, if the rotation shaft of the rotor 53 is connected to, for example, the rotation shaft of the wind turbine, a current flows through the coil 51 due to the rotation of the rotor 53, whereby a wind power generator is configured. However, the application of the motor 50 is not limited to the wind power generator, and it may be used for other generators, or conversely, the rotor 53 may be rotated by passing a current through the coil 51. do not have.

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. big. Then, if the magnet structure 10 is inserted into the slot 54 with the y direction of the magnet structure 10 aligned with the long side 54y and the z direction of the magnet structure 10 aligned with the short side 54z, the magnet is inserted into the slot 54. The structure 10 is housed.

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

As shown in FIG. 6, the magnet structure 10 is inserted in 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 non-magnetic guides 41 and 42 play a role of positioning in the y direction. Further, since the non-magnetic 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, since the magnet 20 is magnetized, it strongly sticks to the inner wall of the slot 54 made of silicon steel plate. Therefore, it is necessary to push the magnet structure 10 in the x direction with a certain strong force. At this time, if the main surface 20N or 20S of the magnet 20 is not covered with the non-magnetic case 30, the main surface 20N or 20S comes into direct contact with the inner wall of the slot 54 and is pushed in the x direction in this state. Strong friction may occur on the 20N or 20S, the rust preventive coat may peel off, and 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 non-magnetic case 30, the rotor 53 is shown in FIG. 7 when viewed from the rotation axis direction (x direction). As shown, the magnet structure 10 can be pushed in with the non-magnetic case 30 interposed therebetween. This reliably prevents the magnet 20 from being scratched or damaged during insertion.

FIG. 8 is a diagram 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 non-magnetic guides 41 and 42 protrudes from the rotor 53. As a result, when the rotor 53 rotates, the heat generated by the magnet structure 10 is efficiently released via the non-magnetic guides 41 and 42. Further, since the non-magnetic guides 41 and 42 have a C-shape having a rod-shaped portion and protrusions provided at both ends thereof, the non-magnetic guide 41 is inserted after the magnet structure 10 is inserted into the slot 54. Even if the magnet 20 is disengaged from the magnet 20, it will not fall out of the slot 54.

FIG. 9 is a diagram 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 legibility of the drawings, FIG. 9 shows a state in which the magnet structure 10 is not inserted in the slot 54.

As shown in FIG. 9, if a plurality of rotors 53 are connected so that the rotation axes match, rotation with a larger torque can be converted into electric power. Such a usage method 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 as viewed from the rotation axis direction are the same in each rotor 53. If the slots 54 are arranged in this way and the distance P between the adjacent rotors 53 is set to twice the protrusion amount of the non-magnetic guides 41 and 42, the slots 54 will be occupied as shown in FIG. 10, which is an enlarged view. When the magnet structure 10 is inserted, the protruding portions of the non-magnetic guides 41 and 42 come into contact with each other in the adjacent magnet structure 10. As a result, the adjacent magnet structures 10 are in a state of supporting each other, so that vibration of the magnet structures 10 during rotation is suppressed.

Moreover, since the non-magnetic guides 41 and 42 project only at both ends in the y direction, the space 44 shown in FIG. 10 is formed between the pair of projecting portions. This space 44 functions as a heat dissipation route, and a high air cooling effect is exhibited.

As described above, according to the present embodiment, since the magnet structure 10 includes the non-magnetic case 30, it is possible to prevent the magnet 20 from being scratched or damaged when it is inserted into the slot 54. Moreover, since the non-magnetic guides 41 and 42 are provided, it is easy to insert the non-magnetic guides 41 and 42 into the slot 54, and it is possible to obtain a high heat dissipation effect. Due to these characteristics, the magnet structure 10 according to the present embodiment is particularly suitable for application to a motor for a wind power generator.

Although the preferred embodiment of the present invention has been described above, the present invention is not limited to the above embodiment, and various modifications can be made without departing from the gist of the present invention, and these are also the present invention. Needless to say, it is included in the range.

10 Magnet structure 20 Magnet 20N First main surface 20S Second main surface 21 First side surface 22 Second side surface 23 Third side surface 24 Fourth side surface 30 Non-magnetic case 31 Opening 41 First non- Magnetic guide 42 Second non-magnetic guide 43 Tapered part 44 Space 50 Motor 51 Coil 52 Stator 53 Rotor 54 Slot 54y Long side of slot 54z Short side of slot P spacing

Claims (9)

The first and second main surfaces having the largest areas facing each other, the first and second side surfaces perpendicular to the first and second main surfaces and facing each other, and the first and second surfaces. A single magnet having a main surface and third and fourth sides perpendicular to the first and second sides and facing each other.
A cylindrical shape that is wound around the magnet without being adhered to the magnet and continuously covers at least a part of the first and second main surfaces of the magnet and most of the first and second side surfaces. Non-magnetic case and
With the first non-magnetic guide attached to the third side surface,
With a second non-magnetic guide attached to the fourth side surface,
The first non-magnetic guide is provided at both ends of the first rod-shaped portion in a direction perpendicular to the first and second side surfaces of the first rod-shaped portion, and the first and second rod-shaped portions are provided, respectively. It is a substantially C-shape including the first and second protrusions bent in the direction perpendicular to the third and fourth side surfaces so as to cover the portion of the side surface close to the third side surface . The thickness in the direction perpendicular to the first and second main surfaces is thinner than the thickness of the magnet.
The second non-magnetic guide is provided at both ends of the second rod-shaped portion in a direction perpendicular to the first and second side surfaces of the second rod-shaped portion, and the first and second rod-shaped portions are provided, respectively. It is a substantially C-shape including the third and fourth protrusions bent in the direction perpendicular to the third and fourth side surfaces so as to cover the portion of the side surface close to the fourth side surface . , A magnet structure characterized in that the thickness in a direction perpendicular to the first and second main surfaces is thinner than the thickness of the magnet. The magnet structure according to claim 1, wherein the first and second main surfaces are magnetic pole surfaces of the magnet. The first and second non-magnetic guides are thinner in the direction perpendicular to the first and second main surfaces than the magnets, according to claim 1 or 2. Magnet structure. The first non-magnetic guide has an inner wall portion that covers the first, second, and third side surfaces of the magnet, and an outer wall portion that faces the inner wall portion.
The second non-magnetic guide has an inner wall portion that covers the first, second, and fourth side surfaces of the magnet, and an outer wall portion that faces the inner wall portion.
A third aspect of the present invention, wherein the end portion of the outer wall portion of the first and second non-magnetic guides located on the first or second side surface side is notched in a tapered shape. The magnet structure according to any one of the following items. The magnet structure according to any one of claims 1 to 4, wherein the magnet is a rare earth sintered magnet, and the surface of the rare earth sintered magnet is rust-proof coated. The non-magnetic case is a film-like sheet formed in a cylindrical shape.
The magnet structure according to any one of claims 1 to 5, wherein the adhesive portion on which the sheets overlap is located on the first or second side surface. The magnet structure according to claim 6, wherein the non-magnetic case is made of PET resin. A motor including a rotor in which a plurality of slots are formed, wherein the magnet structure according to any one of claims 1 to 7 is inserted into each of the plurality of slots. The plurality of slots each have a long side and a short side.
The direction perpendicular to the third and fourth sides of the magnet structure is aligned with the long side, and the direction perpendicular to the first and second main surfaces of the magnet structure is the short side. The motor according to claim 8, wherein the magnet structure is inserted into each of the plurality of slots in a state of being fitted to the above.

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