JP4192086B2 - Exciter, field machine, and electric motor using the same - Google Patents

Description

The present invention relates to an exciter that generates a moving magnetic field by passing an electric current, and an electric motor using the exciter.
Specifically, the present invention relates to an exciter used for an electric motor having field machines arranged inside and outside the exciter and a permanent magnet electric motor using the exciter.

  A permanent magnet motor is an electric motor in which a magnetic field generated by applying an electric current to an exciter (stator) works on a permanent magnet embedded in a field machine (rotor), and the field machine rotates. It is widely used as an electric motor with excellent controllability and environmental resistance and capable of high-efficiency and high-power factor operation regardless of the industrial or consumer electronics field.

10 and 11 show a cross section of a conventional electric motor. FIG. 10 is a plan cross-sectional view, and FIG. 11 is a vertical cross-sectional view.
In this conventional motor, a coil 23 is wound around an annular exciter core 21 along the inner and outer circumferences. An exciter 30 including the exciter core 21 is attached to a shaft 28 via a bearing 29. It is fixed to the supported nonmagnetic base 25. Reference numeral 22 denotes a field machine structure, which is fixed to a field machine yoke 24 that is fixed to the shaft 28 so that a pair of annular permanent magnets 26 are coaxially arranged on both sides with an appropriate distance from the coil structure 21. .
However, in this conventional electric motor, since a sufficient interlinkage magnetic field cannot be obtained inside the exciter core, various proposals have been made.

For example, in Patent Document 1, the exciter core is divided so that the teeth portion and the yoke portion form a pair, and the teeth portions are formed on both the inner periphery and the outer periphery of the exciter core. A method for obtaining a sufficient interlinkage magnetic field inside the core is disclosed. However, conventional motor exciters have been made by laminating non-oriented electrical steel sheets (NO) to reduce iron loss.
A non-oriented electrical steel sheet is a steel sheet having a uniform relative permeability in any direction on the surface of the steel sheet and is widely used as a material with relatively small iron loss. As a material used for the machine, sufficient magnetic properties have not been obtained.
Moreover, since the junction part of the yoke and teeth of the electric motor currently disclosed by patent document 1 is saddle-shaped, and a junction part is a long structure, the magnetic resistance at the time of a magnetic flux passing through this junction part, and There was a problem that iron loss was large.
JP-A-10-271784

  The present invention solves the problems of the prior art as described above, and is an exciter used for an electric motor having field machines arranged inside and outside the exciter, wherein the exciter has a yoke divided in the circumferential direction. It is an object of the present invention to provide an exciter that can reduce the magnetic resistance and iron loss and increase the magnetic flux density (B), and an electric motor using the exciter.

  The present invention is an exciter used for an electric motor in which a field machine is disposed inside and outside an exciter, wherein at least a part of a tooth or a yoke is divided, and at least a part of the tooth or the yoke is one. It is a grain-oriented electrical steel sheet or a bi-directional electrical steel sheet, and the easy magnetization directions of the steel sheets constituting the yoke and the teeth are the circumferential direction and radial direction of the exciter, respectively, preferably, the joint between the yoke and the teeth is linear An exciter capable of reducing the magnetic resistance and iron loss of an exciter whose yoke is divided in the circumferential direction by overlapping the steps and increasing the magnetic flux density (B), and an electric motor using the exciter The gist of the invention is as follows, as described in the claims.

(1) exciter der used for exciter inner and electric motor arranged field磁機outside is, the exciter has a yoke and teeth, at least partially splitting of the yoke or the teeth Has been
At least a part of the yoke or the teeth is a unidirectional electrical steel sheet or a bidirectional magnetic steel sheet,
An excitation machine in which the easy magnetization axis of the yoke is arranged and laminated in the circumferential direction of the exciter, and the easy magnetization axis of the teeth is arranged and laminated in the radial direction of the exciter ;
The joint between the yoke and the teeth is V-shaped with the yoke side convex and the teeth side concave .
The lamination direction of the steel plates of the yoke and the teeth (referring to the normal direction of each laminate plate surface) is not the same direction, and the lamination direction of the steel plates at the interface between the yoke and the teeth is not the same direction. Exciter characterized by that.
(2) The exciter according to claim 1 , wherein the yoke is arranged and laminated in an axial direction of the exciter, and the teeth are arranged and laminated in a circumferential direction of the exciter.
(3) the yoke is laminated and arranged in the radial direction of the exciter, the teeth may exciter according to (1) to be stacked by arranging the axial direction of the exciter.
(4) the yoke is laminated and arranged in the radial direction of the exciter, the teeth may exciter according to (1) to be stacked by arranging in the circumferential direction of the exciter.
(5) The teeth have a cross-sectional width in a direction perpendicular to the axis of the exciter, the side close to the axis of the exciter is narrow and the side far from the axis of the exciter is wide (1) to The exciter according to any one of (4).
(6) An electric motor comprising the exciter according to any one of (1) to ( 5 ).
(7) The electric motor according to ( 6 ), wherein the field machine is made of a steel plate.
(8) The electric motor according to ( 7 ), wherein the field machine is made of any one or more of an electromagnetic steel plate, a sintered magnetic material, and a thin ultra-low carbon steel.
(9) The electric motor according to ( 6 ), wherein the field machine is made of a material obtained by coating single crystal iron powder with an insulating material.
(10) The motor according to any one of ( 6 ) to ( 9 ), wherein the electric motor has a field machine on an outer periphery, and a permanent magnet having a shape along an inner wall of the field machine is attached. The electric motor described.
(11) The electric motor according to any one of ( 6 ) to ( 10), wherein the member that fixes the radial direction of the field machine on the outer peripheral side of the electric motor is a magnetic body.
(12) The electric motor according to any one of ( 6 ) to ( 11), wherein the exciter of the electric motor is a stator and the field machine is a rotor.
(13) The electric motor according to any one of ( 6 ) to ( 11), wherein the exciter of the electric motor is a rotor and the field machine is a stator.

According to the present invention, an exciter used for an electric motor in which a field machine is arranged inside and outside the exciter, the easy magnetization directions of the directional electromagnetic steel sheets constituting the yoke and the teeth are set in the circumferential direction of the exciter, respectively. And the radial direction, and preferably, the junction between the yoke and the tooth is overlapped with a linear step to reduce the magnetic resistance and iron loss of the exciter in which the yoke is divided in the circumferential direction, thereby reducing the magnetic flux density. An exciter capable of increasing (B) and an electric motor using the exciter can be provided, and a remarkable industrially useful effect can be obtained.

  Embodiments of the present invention will be described in detail with reference to FIGS.

<First Embodiment>
FIG. 1 is a diagram showing the structure of an exciter that is a first embodiment of the present invention.
In FIG. 1, 1 is an outer field machine, 2 is an inner field machine, 3 is an exciter, 4 is a yoke, 5 is a tooth, and 6 is an excitation coil.
The exciter 3 is mainly composed of a yoke 4 and a tooth 5 arranged in the circumferential direction, and the yoke 4 and the tooth 5 are interposed between the outer field machine 1 and the inner field machine 2. The yoke 4 is divided in the circumferential direction of the exciter 3.
1, the present invention is directed to an exciter used for an electric motor in which an inner field machine 2 and an outer field machine 1 are arranged inside and outside an exciter 3, and an electric motor using the exciter.
By making the field machine a double structure of the inner side and the outer side, the leakage magnetic flux can be minimized, and as a result, the torque of the electric motor can be increased.
As shown in FIG. 1, in the present invention, the yoke 4 is divided in the circumferential direction of the exciter 3, and the easy axis of the directional electromagnetic steel sheet constituting the yoke 4 is aligned with the circumferential direction of the exciter 3 (the yoke Arranged in the direction of the arrow) and laminated, the easy magnetization axis of the grain-oriented electrical steel sheet constituting the tooth 5 is arranged in the radial direction of the exciter 3 (in the direction of the arrow of the tooth).

Here, the grain-oriented electrical steel sheet is an electrical steel sheet in which the easy magnetization direction is a specific direction, and has a magnetic property superior to the non-oriented electrical steel sheet in the easy magnetization direction.
For example, as shown in FIG. 2, in the grain-oriented electrical steel sheet, the relative permeability μ _R in the rolling direction is significantly larger than the relative permeability μ _T in the non-rolling direction, and it is easy to flow a magnetic flux in the rolling direction. Have nature.
Therefore, by matching the flow direction of the magnetic flux in the yoke with the direction of easy magnetization of the grain-oriented electrical steel sheet, the flow of the magnetic flux can be made smooth, and as a result, the magnetic flux density (B) can be strengthened and the magnetic flux crosses. Therefore, it is possible to prevent the generation of a rotating magnetic field having a large magnetic resistance in the portion to be performed, and to reduce iron loss in the exciter.
On the other hand, the bi-directional electrical steel sheet is an electrical steel sheet having two easy magnetization directions, and has magnetic properties superior to the non-oriented electrical steel sheet in the easy magnetization direction. As shown in FIG. 13, in the bi-directional electrical steel sheet, the relative permeability μ _{R in the} rolling direction and the relative permeability μ _{T in the} direction perpendicular to the rolling direction are remarkably larger than those in the other directions. In addition, the magnetic flux easily flows in the vertical direction.
Therefore, the flow of the magnetic flux can be made smooth by matching the direction of flow of the magnetic flux flowing through the yoke with the direction of easy magnetization of any of the bidirectional magnetic steel sheets. As a result, the magnetic flux density (B) can be strengthened, and the generation of a rotating magnetic field having a large magnetic resistance generated at the portion where the magnetic flux intersects can be prevented, and the iron loss of the exciter can be reduced.

Conventionally, as shown in FIG. 16, since the yoke and the teeth are laminated in the same direction, the direction of the magnetic flux changes in the same plane when the magnetic flux passes through the boundary between the yoke and the tooth. For this reason, a rotating magnetic field having a large magnetic resistance is generated in this portion, and the iron loss is remarkably increased.
In the above, the rotating magnetic field refers to a magnetic field in which the magnetic characteristics change in a curved manner depending on the position in the XY plane, as shown in FIG. 14, for example, as shown in FIG. It is a magnetic field different from the magnetic field.
The inventors of the present application have measured the iron loss of various types of stators and found that this rotating magnetic field is likely to be generated at a place where the direction of magnetic flux changes within the same plane as the steel plate surface. Then, in order to prevent the occurrence of this rotating magnetic field, and conceived that may need to change the direction of the magnetic flux in the steel sheet surface and the leveling plane. By changing the stacking direction of the yoke 1 and the teeth 2 to be different directions, the direction change of the magnetic flux in the plane was reduced. As a result, the generation of the rotating magnetic field was suppressed, and the iron loss could be significantly reduced.
Specifically, as shown in FIG. 17, the yoke 1 may be arranged and laminated in the radial direction of the exciter, and the teeth 2 may be arranged and laminated in the axial direction of the exciter. Further, as shown in FIG. 18, the yoke 1 may be arranged and laminated in the radial direction of the exciter, and the teeth 2 may be arranged and laminated in the circumferential direction of the exciter. As shown, the yoke 1 may be arranged and laminated in the axial direction of the exciter, and the teeth 2 may be arranged and laminated in the circumferential direction of the exciter.
By the way, it is preferable that the teeth 5 are arranged in the radial direction of the exciter 3 and that the outer peripheral side of the exciter 3 is wider than the inner peripheral side. This is because by making the outer peripheral side of the teeth 5 wider, the magnetic flux flowing through the outer field machine 1 can be increased, and a larger torque can be obtained.
Further, in the present invention, the exciting coil 6 may be wound around the teeth 5 as in the conventional method, but the exciting coil 6 may be concentratedly wound around the yoke 4 as shown in FIG. preferable.
By winding the exciting coil 6 around the yoke 4, the length of the tooth 5 can be shortened as compared with the conventional case, and as a result, the diameter of the motor can be reduced and the size can be reduced.
Further, by winding the exciting coil 6 around the yoke 4 in a concentrated manner, for example, the coil end can be made compact compared to distributed winding wound around every other yoke, so that the space around the exciter can be used effectively. Therefore, the electric motor can be reduced in size.

<Second Embodiment>
3 and 4 are diagrams showing the structure of an exciter that is the second embodiment of the present invention.
3 and 4, 4 indicates a yoke, and 5 indicates a tooth.
As shown in FIG. 3, the joint portion between the yoke 4 and the teeth 5 is formed in a mountain-shaped straight line, so that the joint portion is compared with the saddle type disclosed in the above-mentioned JP-A-10-271784. Therefore, the iron loss due to the joint can be remarkably reduced.
The cut surface of the steel sheet has a remarkably large magnetic resistance due to the effect of stress concentration due to plastic working. Therefore, it is preferable to shorten the cut length as much as possible, and make the cut portion (joint portion) linear as in the present invention. As a result, the magnetic resistance and the iron loss can be significantly reduced.

Further, as in the present embodiment, the shape of the joint portion between the yoke 4 and the tooth 5 is a mountain shape, so that the magnetic flux flowing from the yoke 4 to the tooth 5 is easily bent in the axial direction of the tooth 5. The flow can be made even smoother. FIG. 4 is a detailed view of a portion A in FIG. 3, showing a joint portion between the yoke 4 and the tooth 5.
In the present embodiment, as shown in the upper diagram of FIG. 4, the joint portion between the yoke 4 and the tooth 5 is overlapped with two steps in the stacking direction.
In this way, by superimposing the joint between the yoke 4 and the tooth 5 with two steps in the stacking direction, the mechanical strength of the joint can be increased, and the magnetic characteristics of the joint can be made smooth. As a result, the magnetoresistance of the stator can be reduced.
In the lower diagram of FIG. 4, the joint portion between the yoke 4 and the tooth 5 is overlapped with three steps in the stacking direction. Thus, by increasing the number of steps, the mechanical strength of the joint can be further increased, and the magnetic resistance of the exciter can be reduced.

<Third Embodiment>
FIG. 5 is a diagram showing the structure of an exciter that is the third embodiment of the present invention.
In FIG. 5, 4 indicates a yoke and 5 indicates a tooth.
As shown in FIG. 5, in this embodiment, the joint part of the yoke 4 and the teeth 5 is made into the rectangular shape.
By making the joint between the yoke 4 and the teeth 5 rectangular, the length of the joint can be shortened as compared with the mountain shape of the second embodiment, so that the magnetic resistance can be reduced accordingly. On the other hand, it is slightly inferior to the second embodiment in terms of smoothing the flow of magnetic flux.
In addition, since the point which provides a level | step difference in the junction part of the yoke 4 and the teeth 5 and overlaps is the same as that of 2nd Embodiment, it abbreviate | omits.

<Fourth Embodiment>
6 and 7 are diagrams showing the structure of an exciter that is the fourth embodiment of the present invention.
6 and 7, 4 indicates a yoke and 5 indicates a tooth.
As shown in FIGS. 6 and 7, in the present embodiment, the yoke 4 and the teeth 5 are used.
The shape of the joint part is trapezoidal with the tooth side as the hypotenuse. By making the joint portion between the yoke 4 and the tooth 5 trapezoidal, the length of the joint portion can be shortened compared to the mountain shape of the second embodiment, and accordingly, the magnetic resistance of the exciter is reduced accordingly. In addition, the magnetic flux can easily flow in either the outer peripheral side or the inner peripheral side of the exciter.

Specifically, in FIG. 6, the trapezoidal hypotenuse is directed toward the outer periphery of the exciter, so that magnetic flux easily flows on the outer periphery, and in FIG. 7, the trapezoid hypotenuse is directed toward the outer inner periphery of the exciter. Therefore, the magnetic flux easily flows on the inner peripheral side.
The selection in FIGS. 6 and 7 is preferably determined by the side of the outer periphery or the inner periphery that flows a large amount of magnetic flux. For example, when a large amount of magnetic flux flows in the outer periphery, the embodiment of FIG. 6 is preferably selected. .
In addition, since the point which provides a level | step difference in the junction part of the yoke 4 and the teeth 5 and overlaps is the same as that of 2nd Embodiment, it abbreviate | omits.

<First to fourth common embodiments>
FIG. 8 is a diagram showing a structure of an exciter common to the first to fourth embodiments of the present invention and an electric motor using the exciter. FIG. 8 is an example in which the structure of the electric motor is embodied with 4 poles, and does not limit the technical range such as the shape and position of the permanent magnet and the number of teeth of the exciter.
In FIG. 8, 1 is an outer field machine, 2 is an inner field machine, 3 is an exciter, 4 is a yoke, 5 is a tooth, 7 is an outer permanent magnet, and 8 is an inner permanent magnet. Also, the dotted arrow in FIG. 8 illustrates the magnetic flux density at time t0 in FIG. 9. A thick dotted line represents a strong magnetic flux density, and a thin dotted line represents a weak magnetic flux density.
In this embodiment, exciting coils (not shown) are concentratedly wound around the yokes so that three-phase exciting currents U, V, and W shown in FIG. The flow of magnetic flux can be made in the direction shown by the arrow in FIG.
Note that U ′ and V′W ′ in FIG. 8 indicate excitation currents obtained by inverting the sign of U, V, and W.
In FIG. 8, excitation currents of different phases are applied to adjacent yokes. However, for example, excitation currents of the same phase may be applied by setting two adjacent yokes as a set.
Further, by applying the exciter shown in the first to fourth embodiments to an electric motor, it is possible to provide an electric motor with a small iron loss and a large output torque.

Further, in the present invention, the material of the field machine is not limited, but is preferably any one of a magnetic steel sheet, a sintered magnetic material, a thin ultra-low carbon steel, and a material obtained by coating single crystal iron powder with an insulating material.
First, magnetic steel sheets are superior in magnetic properties compared to other materials such as ordinary steel, and therefore iron loss in field machines can be reduced.
Furthermore, in the sintered magnetic material, since the field machine can be constituted by the metal powder sintered body, the mechanical design and the magnetic design can be performed independently, thereby increasing the degree of freedom in the field machine design and generating from the permanent magnet. A field machine with high reliability such as mechanical strength and durability can be obtained while effectively using magnetic flux.
Moreover, since the thin ultra-low carbon steel is a kind of ordinary steel, the material cost is very low, so it is easy to procure the material.
Furthermore, a material in which single crystal iron powder is coated with an insulating material is, for example, coated with a single crystal iron powder having a <001> orientation in the major axis direction with an insulating resin and poured into a mold together with a thermosetting resin. By making the direction of the magnetic flux flowing through the field machine coincide with the direction of easy magnetization of the single crystal iron powder, the iron loss in the field machine can be reduced.
In the present invention, the exciter may be a stator and the field machine may be a rotor, and the exciter may be a rotor and the field machine may be a stator.

FIG. 12 is a diagram showing a planar structure of a field machine that is the fifth embodiment of the present invention. In FIG. 12, 31 indicates an outer field machine, and 32 indicates a permanent magnet. The force acting on the permanent magnet in the outer field machine is almost the centrifugal force due to the rotation. As shown in the electric motor plan view shown in FIG. Is pressed against the field machine by centrifugal force, so that there is no problem in supporting the permanent magnet from the viewpoint of strength. Also, as shown in FIG. 12, it is desirable to embed the permanent magnet in the field machine so that the field machine inner circumferential surface becomes a single circumferential surface. Further, the material of the field machine is preferably an electromagnetic steel plate, sintered magnetic material or thin ultra-low carbon steel (SULC). Especially, since a three-dimensional magnetic circuit design is possible and iron loss is reduced, single crystal iron powder is used. Is desirable. By using such a field machine, the method for fixing the permanent magnet can be simplified, and the distance between the permanent magnet and the exciter teeth can be shortened, so that the torque can be improved.
Further, as shown in FIG. 12, the outer field machine 31 is configured by laminating steel plates in the axial direction, and a structural member 9 is arranged around the steel plate in order to fix the radial direction of the steel plates. By using the structural member 9 as a magnetic material, it is possible to increase the total amount of magnetic flux in the outer field machine and to obtain a higher torque.

It is a figure which shows the structure of the exciter which is the 1st Embodiment of this invention. It is a figure which shows the relationship between the direction of the magnetic flux of a unidirectional electrical steel plate, and an iron loss. It is a figure which shows the structure of the exciter which is the 2nd Embodiment of this invention. It is a figure which shows the structure of the exciter which is the 2nd Embodiment of this invention. It is a figure which shows the structure of the exciter which is the 3rd Embodiment of this invention. It is a figure which shows the structure of the exciter which is the 4th Embodiment of this invention. It is a figure which shows the structure of the exciter which is the 4th Embodiment of this invention. It is a figure which shows the structure of the exciter common to the 1st thru | or 4th embodiment of this invention, and an electric motor using the same. It is explanatory drawing of a three-phase exciting current. It is a cross-sectional view of a conventional electric motor. It is a longitudinal cross-sectional view of the conventional electric motor. It is a figure which shows the structure of the field machine which is the 1st thru | or 4th embodiment of this invention. It is a figure which shows the characteristic of the relative magnetic permeability ((micro | micron | mu)) of the bidirectional magnetic steel plate used for this invention. It is explanatory drawing of an alternating magnetic field. It is explanatory drawing of a rotating magnetic field. It is a figure which shows the lamination | stacking state of the conventional exciter. It is a figure which shows the structure of the exciter which is the 1st Embodiment of this invention. It is a figure which shows the structure of the exciter which is the 1st Embodiment of this invention. It is a figure which shows the structure of the exciter which is the 1st Embodiment of this invention.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Outer field machine 2 Inner field machine 3 Exciter 4 Yoke 5 Teeth 6 Excitation coil 7 Outer permanent magnet 8 Inner permanent magnet 9 Structural member 21 Exciter core 22 Field machine component 23 Coil 24 Field machine Yoke 25 Nonmagnetic base 26 Permanent magnet 28 Shaft 29 Bearing 30 Exciter 31 Outside field machine 32 Permanent magnet

Claims (13)

Exciter der used in the electric motor arranged a field磁機inside and outside of the exciter is, the exciter has a yoke and teeth, at least a portion of said yoke or said tooth is divided ,
At least a part of the yoke or the teeth is a unidirectional electrical steel sheet or a bidirectional magnetic steel sheet,
An excitation machine in which the easy magnetization axis of the yoke is arranged and laminated in the circumferential direction of the exciter, and the easy magnetization axis of the teeth is arranged and laminated in the radial direction of the exciter ;
The joint between the yoke and the teeth is V-shaped with the yoke side convex and the teeth side concave .
The lamination direction of the steel plates of the yoke and the teeth (referring to the normal direction of each laminate plate surface) is not the same direction, and the lamination direction of the steel plates at the interface between the yoke and the teeth is not the same direction. Exciter characterized by that. 2. The exciter according to claim 1 , wherein the yoke is arranged and laminated in an axial direction of the exciter, and the teeth are arranged and laminated in a circumferential direction of the exciter. 2. The exciter according to claim 1 , wherein the yoke is arranged and laminated in a radial direction of the exciter, and the teeth are arranged and laminated in an axial direction of the exciter. The exciter according to claim 1 , wherein the yoke is arranged and laminated in a radial direction of the exciter, and the teeth are arranged and laminated in a circumferential direction of the exciter. 5. The tooth has a cross-sectional width in a direction perpendicular to the axis of the exciter such that the side close to the axis of the exciter is narrow and the side far from the axis of the exciter is wide. The exciter according to any one of the above. An electric motor comprising the exciter according to any one of claims 1 to 5 . The electric motor according to claim 6 , wherein the field machine is made of a steel plate. 8. The electric motor according to claim 7 , wherein the field machine is made of any one or more of an electromagnetic steel plate, a sintered magnetic material, and a thin ultra low carbon steel. The electric motor according to claim 6 , wherein the field machine is made of a material obtained by coating single crystal iron powder with an insulating material. The motor has a field磁機the outer circumference, the motor according to any one of claims 6 to 9, characterized in that the permanent magnets of the shape along the inner wall of the field磁機is attached . The electric motor according to any one of claims 6 to 10 members for fixing the radial direction of the outer peripheral side of the field磁機of the motor is characterized in that it is a magnetic body. The electric motor of the exciter is a stator, the electric motor according to any one of claims 6 to 11 and field磁機is characterized in that it is a rotor. Wherein a motor exciter is a rotor, the electric motor according to any one of claims 6 to 11 and field磁機is characterized in that it is a stator.

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