WO2014010484A1

WO2014010484A1 - Electric motor

Info

Publication number: WO2014010484A1
Application number: PCT/JP2013/068254
Authority: WO
Inventors: 樋口　剛; 真樹松本; 勇是松尾
Original assignee: 国立大学法人長崎大学
Priority date: 2012-07-09
Filing date: 2013-07-03
Publication date: 2014-01-16

Abstract

An electric motor that allows for a reduction in the leakage of magnetic flux in the axial direction at a coil end part and that allows for a reduction in manufacturing cost while improving efficiency has a rotor (1) having a rotating shaft, and a core section in which the dimension in the radial direction orthogonal to the axial direction is larger than the dimension in the axial direction parallel to the rotating shaft of the rotor (1). The electric motor is provided with a stator (10) that produces a magnetic field upon coils (11a, 11b, 11c) wound on the core section being energized, and provides rotational torque by transmitting electromagnetic force to the rotor. The electric motor is provided with a high-magnetic-permeability core (10a) in the vicinity of the coil end of the core section of the stator (10) and at least in the core section including directly below the coil.

Description

Electric motor

The present invention relates to a flat-type electric motor suitable for application to a switched reluctance motor, a permanent magnet synchronous motor, or the like having a stator having a radial dimension larger than an axial dimension.

In recent years, electric motors are often used in electric vehicles such as hybrid cars and electric cars, urban transportation devices such as elevators and escalators, and home appliances such as washing machines and heat pump water heaters. The electric motor has been demanded to have a flat structure having a larger radial dimension than an axial dimension in order to improve power performance while reducing the size of the product.

Generally, an electric motor generates a magnetic field by energizing a coil wound around a core portion of a stator, and transmits an electromagnetic force to the rotor to give a rotational torque. The transmission of the electromagnetic force that contributes to the generation of this rotational torque acts in a plane orthogonal to the motor axis, so that the continuously wound coil straddles the axial end of the core portion of the stator. The portion (hereinafter, this portion is referred to as a coil end) does not contribute to the generation of rotational torque.

On the contrary, since the magnetic flux leaks in the axial direction at the coil end portion, it is a factor that causes a reduction in efficiency that the generated torque is small for the input power. In an electric motor having a normal aspect ratio (axial dimension / radial dimension) of 1 or more, the influence of this coil end portion is small in proportion, but cannot be ignored in an electric motor having a flat structure with an aspect ratio of less than 1.

Non-Patent Document 1 discloses an example of improving torque efficiency. According to this, for a switched reluctance motor having an aspect ratio of about 0.3, a permement (Fe—Co alloy), which is a highly permeable material, is used instead of a conventional silicon steel plate as a core material of a stator and a rotor. ) Is used. This is intended to increase the efficiency by making the entire core a highly permeable material, due to its high saturation magnetic flux density and low core loss.

On the other hand, Patent Document 1 and Patent Document 2 disclose examples in which a high permeability material is used for a part of a core. In FIG. 81 of Patent Document 1, it is disclosed that the tip of teeth (teeth) which is a portion of the core portion of the stator facing the rotor is a permendur. Similarly, FIGS. 5 and 6 of Patent Document 2 disclose that a part of the tip of the teeth of the core portion of the stator is made of permalloy (Fe—Ni alloy) which is a highly permeable material. These are all formed by laminating the high magnetic permeability material in the axial direction, and improve the efficiency of generating rotational torque. Further, as described in paragraph [0397] of Patent Document 1, an increase in manufacturing cost is suppressed by partially using an expensive high magnetic permeability material.

JP 2011-177021 A Japanese Patent Laid-Open No. 11-168863

By the way, according to the electric motor having a flat structure according to the conventional example, if the entire core portion of the stator is made of a highly permeable material as described in Non-Patent Document 1, the efficiency can be improved. Since the material is expensive, there is a problem that the manufacturing cost of the electric motor becomes high.

If the high permeability material is partially used in the core portion of the stator as in

Patent Documents

1 and 2, the manufacturing cost can be suppressed, but the high permeability material is laminated in the axial direction. To do. For this reason, we are anxious about the problem of not having an effect with respect to the leakage of the magnetic flux to the axial direction in the coil end part in a flat structure electric motor.

The present invention has been made in view of such problems, and devise the structure of the front and back surfaces of the core portion of the stator so that leakage of magnetic flux in the axial direction at the coil end portion can be reduced. A further object is to provide a flat-type electric motor capable of reducing the manufacturing cost while improving the efficiency.

In order to solve the above-described problem, an electric motor according to claim 1 includes a rotor having a shaft and a radial dimension orthogonal to the axial direction with respect to the axial dimension parallel to the shaft of the rotor. Has a large core part. The electric motor includes a stator that energizes a coil wound around the core portion to generate a magnetic field, and transmits electromagnetic force to the rotor to give a rotational torque. The electric motor is provided with a shield member having a high magnetic permeability and a large saturation magnetic flux density in the vicinity of the coil end of the core portion of the stator, and at least in the core portion including immediately below the coil.

According to the electric motor of the first aspect, the permeability of the magnetic flux in the front and back surfaces of the core portion orthogonal to the axial direction directly below the stator coil can be improved, so that the magnetic flux in the axial direction at the coil end portion can be improved. Leakage can be reduced and the total magnetic flux can be increased.

The electric motor according to a second aspect is the electric motor according to the first aspect, wherein the shield member is provided on the entire surface of at least one of the front and back of the core portion of the stator orthogonal to the axial direction.

According to a third aspect of the present invention, in the electric motor according to the second aspect, the core portion of the stator has a yoke portion, and the shield member is provided only in the yoke portion of the stator.

The electric motor according to claim 4 is the electric motor according to claim 2, wherein the shield member is provided only in the core portion around which the coil is wound.

According to a fifth aspect of the present invention, in the electric motor according to the fourth to fourth aspects, a permendur is used for the shield member.

The electric motor according to claim 6 is the electric motor according to claims 1 to 4, wherein the electric motor is a switched reluctance motor.

According to the electric motor of the present invention, a shield member having a high magnetic permeability and a high saturation magnetic flux density is provided in the vicinity of the coil end of the core portion of the stator, and at least in the core portion including immediately below the coil. It is

With this structure, it is possible to improve the magnetic flux permeability in the front and back surfaces of the core portion orthogonal to the axial direction directly below the stator coil, so that the magnetic flux leakage in the axial direction at the coil end portion can be reduced. . In addition, the total magnetic flux can be increased. This makes it possible to provide a flat switched reluctance motor, a permanent magnet synchronous motor, and the like that are highly efficient and low in manufacturing cost.

1 is a partially crushed perspective view illustrating a configuration example of a flat electric motor 100 according to a first embodiment. FIG. 3 is a partially broken perspective view illustrating a configuration example of a core portion of the stator 10. FIG. 6 is a characteristic diagram illustrating an example of a torque waveform of the flat electric motor 100. It is a graph which shows the material characteristic example of a shield member. It is a perspective view of partial crushing which shows the example of composition of flat type electric motor 200 concerning a 2nd embodiment. FIG. 6 is a characteristic diagram illustrating an example of a torque waveform of a flat electric motor 200. It is a perspective view of partial crushing which shows the example of composition of the flat type electric motor 300 concerning a 3rd embodiment. 4 is a graph showing an example of torque characteristics of a flat electric motor 300. FIG.

Hereinafter, the best mode for carrying out the present invention (hereinafter referred to as an embodiment) will be described.

<First Embodiment>
A configuration example and an operation example of the flat electric motor 100 according to the first embodiment will be described with reference to FIGS. A flat electric motor 100 shown in FIG. 1 can be mounted on an electric vehicle such as a hybrid vehicle or an electric vehicle, an urban transportation device such as an elevator or an escalator, and a home appliance such as a washing machine or a heat pump water heater.

The flat electric motor 100 includes a rotor 1 and a stator 10. The rotor 1 has an inner rotor portion 1a, an outer rotor portion 1b, a connecting plate 1c, and a rotating shaft 4. The rotating shaft 4 is made of a metal rod having a predetermined length, and a disk-shaped connecting plate 1 c is fixed to the rotating shaft 4. The connecting plate 1c serves as a base in the rotor 1, and a hole for attaching the rotating shaft 4 is opened at the center of the connecting plate 1c before assembly. An annular inner rotor portion 1a is fixed to a predetermined inner peripheral portion of the connecting plate 1c, and an annular outer rotor portion 1b is fixed to the outer peripheral portion.

The material of the inner rotor portion 1a, the outer rotor portion 1b, the connecting plate 1c, etc. is a non-magnetic material such as aluminum (Al) or an alloy thereof, for example. The inner rotor portion 1a and the like are integrally formed by a casting method such as a die casting method in which molten Al is poured into a precise mold under pressure. In this example, the inner diameter of the inner rotor portion 1a is Di, and the outer diameter of the outer rotor portion 1b is Do.

Eight inner segment cores 2 are fixed to the outer diameter side of the inner rotor portion 1a. The material of the inner segment core 2 is a magnetically permeable material, and for example, a plurality of silicon steel plates having a predetermined arc shape are laminated in the axial direction and bonded to each other to be manufactured in a block shape.

Eight outer segment cores 3 are also fixed to the inner diameter side of the outer rotor portion 1b. The material of the outer segment core 3 is also a magnetically permeable material. For example, a plurality of silicon arc steel plates having a predetermined arc shape are laminated in the axial direction and fixed to each other to be manufactured in a block shape. The one end portion 4a and the other end portion 4b of the rotating shaft 4 are rotatably supported (axially supported) corresponding to the respective bearing portions of the entire base portion (not shown).

A stator 10 is disposed between the outer diameter side of the inner rotor portion 1a and the inner diameter side of the outer rotor portion 1b. The stator 10 has a core portion having a large radial dimension perpendicular to the axial direction with respect to the axial dimension parallel to the rotating shaft 4. In this example, when the aspect ratio is the ratio of the dimension in the radial direction perpendicular to the axial direction to the dimension in the axial direction of the core portion of the stator 10, the aspect ratio of the core portion is less than 1. As shown in FIG. 2, the core portion of the stator 10 includes a highly permeable core 10a and a permeable core 10b.

The magnetically permeable core 10b forms the main part of the core portion of the stator 10. The planar shape of the core portion of the stator 10 includes an inner teeth portion 10c (Inside Teeth: IT) facing the inner segment core 2, an outer teeth portion 10d (Outside Teeth: OT) facing the outer segment core 3, and a circle. It consists of a yoke portion 10e that is connected in an annular shape.

The inner teeth portion 10c has a fan-shaped portion widened from the annular yoke portion 10e toward the outer diameter side of the inner rotor portion 1a. Twelve fan-shaped portions of the inner teeth portion 10c are provided at intervals of 30 °. The outer tooth portion 10d has a fan-shaped portion widened from the yoke portion 10e toward the inner diameter side of the outer rotor portion 1b. Twelve fan-shaped portions of the outer tooth portion 10d are also provided every 30 °.

The magnetically permeable core 10b is formed from a plate of a magnetically permeable material having a predetermined shape (for example, a silicon steel plate: component = 4Si + Fe, relative magnetic permeability = 7000, Hc = 40 A / m, Is = 1.97, Tc = 690 ° C.). The portion 10c, the outer tooth portion 10d, and the yoke portion 10e are cut out in an annular shape so as to be punched. It is formed by laminating a predetermined number of the punched annular members. In this example, T is the total thickness after lamination of the magnetically permeable core 10b.

The highly permeable core 10a is fixed to the front and back surfaces of the permeable core 10b in the axial direction. The high magnetic permeability core 10a constitutes an example of a shield member. The high magnetic permeability core 10a has a high magnetic permeability and a high saturation magnetic flux density. In this example, the high magnetic permeability core 10a is in the vicinity of the coil end of the core portion of the stator 10, and is formed on the entire surface of the inner teeth portion 10c, the outer teeth portion 10d, and the yoke portion 10e that connects them in an annular shape. A shield member is provided.

Permendur (component = 50 Co + Fe, relative magnetic permeability = 5000, Hc = 160 A / m Is = 2.45, Tc = 980 ° C.) or the like is used for the high magnetic permeability core 10a.

The high magnetic permeability core 10a is formed by laminating a predetermined number of shield member plates (for example, permendur plates) having a high permeability and a high saturation magnetic flux density in a predetermined shape. In this example, a permendur plate is cut out to form one sheet, following a template having the same shape as the inner teeth portion 10c and the outer teeth portion 10d including the yoke portion 10e. In this example, the thickness of one surface after laminating a plurality of permendur plates constituting the highly permeable core 10a is defined as t. The thickness T ′ of the stator core is (T + 2t).

2,

coils

11a, 11b, and 11c are wound around the yoke portion 10e of the stator 10 so as to surround the yoke portion 10e in the radial direction. Four sets of the coils 11a are arranged in the core portion of the stator 10 with the

coils

11b and 11c adjacent to each other in between, and they are connected to each other. The

coils

11b and 11c are similarly arranged and connected. The winding method of the stator 10 is concentrated winding. The total number of

coils

11a, 11b, 11c, etc. is twelve. The core portion of the stator 10 and the

coils

11a, 11b, and 11c are integrated by a resin mold (not shown) and fixed to an entire base portion (not shown). Thus, a flat electric motor 100 is configured.

Next, an operation example of the flat motor 100 will be described. According to the flat electric motor 100 according to this embodiment, a 12/8 switched reluctance (hereinafter referred to as SR) motor having a 12-pole stator 10 having a three-phase connection and an 8-pole rotor 1 is configured. ing. The stator 10 shown in FIG. 1 generates a magnetic field by energizing the

coils

11a, 11b, and 11c wound around the core portion, and transmits an electromagnetic force to the rotor 1 to rotate torque (reluctance torque). give.

In this example, the

coils

11a, 11b, and 11c are connected to a control device (not shown). The control device passes a current so as to apply a DC magnetic field to the

coils

11a, 11b, and 11c. For example, a magnetic field that rotates along the annular shape of the stator 10 is generated by switching the DC magnetic field in the order of the coil 11a → the coil 11b → the coil 11c.

The rotor 1 rotates by the inner segment core 2 and the outer segment core 3 of the rotor 1 attracting to the rotating magnetic field. Torque generated by the rotation of the rotor 1 is output from the other end 4 b of the rotating shaft 4 to the outside of the flat electric motor 100. The load is driven by this torque.

Here, the torque characteristics of the flat electric motor 100 will be described with reference to FIG. In this embodiment, the high magnetic permeability core 10a is provided on the entire surface of at least one of the front and back of the core portion of the stator 10 orthogonal to the axial direction. In the example of the torque waveform shown in FIG. 3, the inner rotor portion 1a has an inner diameter Di of 140 mm, the outer rotor portion 1b has an outer diameter Do of 349.2 mm, the magnetically permeable core 10b of the stator 10 is a silicon steel plate, and its thickness This is a torque characteristic of the flat electric motor 100 when T is 30 mm, the highly permeable core 10a is a permendur, and the thickness t is 3 mm, that is, the thickness T ′ of the stator core is 36 mm. .

3, the vertical axis represents torque [Nm], and the horizontal axis represents the rotation angle [°] of the rotor 1. The solid line in the figure is an example of torque characteristics of the electric motor 100 (hereinafter referred to as the method of the present invention), and the broken line is not provided with the highly permeable core 10a, and the core portion of the stator 10 has a thickness T of 30 mm. This is an example of torque characteristics (hereinafter referred to as a conventional method) when only the magnetically permeable core 10b of a silicon steel plate is used.

According to the conventional method, there is a torque peak of 35 N-m near the rotation angle of 3 ° to 4 °, and then the torque decreases rapidly. After the rotation angle of 6 °, the torque is below 30 N-m. On the other hand, according to the method of the present invention, there is a torque peak of 42 Nm near the rotation angle of 3 °, and the torque is 30 Nm or more up to the rotation angle of 9 °. The average torque is 22.9 N-m for the conventional system and 27.0 N-m for the system of the present invention, which is an improvement of 18% in the system of the present invention compared to the conventional system.

On the other hand, when the permeable core 10b is a silicon steel plate, the thickness T is 24 mm, the highly permeable core 10a is a permendur, and the thickness t is 3 mm, that is, the thickness T ′ of the stator core is 30 mm. The average torque is 24.4 Nm. The average torque is improved by 6.6% compared to the conventional method in which the core portion of the stator 10 is made only of the permeable core 10b of a silicon steel plate having a thickness T of 30 mm.

Here, referring to FIG. 4, an example of BH characteristics between permendur and a silicon steel plate will be compared. In FIG. 4, the horizontal axis represents the magnetic field strength H [A / m], and the vertical axis represents the magnetic flux density B [T]. The characteristic curve plotted with a white diamond on the solid line is permendur, and the characteristic curve plotted with a white rectangle on the solid line is a silicon steel plate (50H1300).

In both cases, the magnetic flux density B is saturated and the gradient is constant when the magnetic field strength H is around 1000 A / m, but the saturation magnetic flux density is higher for the permendur. In addition, the ramp up to that point is larger for permendur. That is, the permeability of permendur is higher than that of silicon steel plate. As a result, the permeability of the magnetic flux in the plane orthogonal to the rotation axis of the electric motor 100 on the core surface directly under the coil is improved, the leakage of magnetic flux in the axial direction is reduced, and the total magnetic flux density is increased. It can be seen that the torque characteristics are improved.

As described above, according to the flat electric motor 100 according to the first embodiment, the inner teeth portion 10c, the outer teeth portion 10d, and the annular teeth are connected in the vicinity of the coil end of the core portion of the stator 10. A highly permeable core 10a is provided on the entire surface of the yoke portion 10e (in the plane orthogonal to the rotation axis).

With this structure, the permeability of the magnetic flux in the front and back surfaces of the core portion orthogonal to the axial direction directly below the coil can be improved, so that leakage of magnetic flux in the axial direction at the coil end portion is reduced, and the total magnetic flux Will be able to increase. This makes it possible to provide a more efficient flat 12/8 SR motor or the like than when the entire core portion of the stator 10 is made of a silicon steel plate while suppressing an increase in manufacturing cost.

<Second Embodiment>
Next, a flat electric motor 200 according to the second embodiment will be described with reference to FIGS. 5 and 6. According to the flat type electric motor 200 shown in FIG. 5, the highly magnetic core 10 a ′ is provided only in the portion corresponding to the yoke portion 10 e in FIG. 2 in the core portion of the stator 10 ′. The stator 10 ′ of the electric motor 200 includes a magnetically permeable core 10b and a highly permeable core 10a ′. The permeable core 10b is the same as the permeable core 10b of the electric motor 100 shown in FIG. The high magnetic permeability core 10a ′ has an annular shape corresponding to the yoke portion 10e of FIG. 2, and is fixed to the front and back surfaces of the magnetic permeability core 10b to form the core portion of the stator 10 ′. Thereafter, the

coils

10a, 11b, and 11c are wound around the yoke portion 10e of the stator 10 ′ of the electric motor 200 so as to surround the yoke portion 10e in the radial direction, whereby the electric motor 200 is manufactured.

Here, the torque characteristics of the flat electric motor 200 will be described with reference to FIG. In this embodiment, the highly permeable core 10a 'is provided only in the yoke portion 10e of the core portion of the stator 10'. In the torque waveform example shown in FIG. 6, the inner diameter Di of the inner rotor portion 1a is 140 mm, the outer diameter Do of the outer rotor portion 1b is 349.2 mm, the magnetically permeable core 10b of the stator 10 ′ is a silicon steel plate, This is a torque characteristic of the flat electric motor 200 when the thickness T is 30 mm, the highly permeable core 10a ′ is a permendur, and the thickness t is 3 mm.

The solid line in the figure is the torque characteristic of the electric motor 200 (the method of the present invention), and the broken line is an example of the torque characteristic when the core portion of the stator 10 ′ is only a permeable core 10 b of a silicon steel plate with a thickness T of 30 mm ( Conventional method). According to the conventional method shown by the broken line, there is a torque peak of 35 Nm near the rotation angle of 3 ° to 4 ° of the rotor 1, and then the torque decreases rapidly, and the torque is 30 N after the rotation angle of 6 °. Below -m.

On the other hand, according to the method of the present invention shown by the solid line, the torque of 35 Nm is maintained from the vicinity of the rotation angle 3 ° of the rotor 1 to the vicinity of 8 °, and the torque is 30 N until the rotation angle 9 °. -M or more. The average torque is 22.9 Nm for the conventional method and 25.6 Nm for the method of the present invention. Compared to the conventional method, the method of the present invention is improved by 11.8%.

As described above, according to the flat type electric motor 200 according to the second embodiment, the annular high magnetic permeability core 10a ′ is used only in the vicinity of the coil end portion of the yoke portion 10e of the core portion of the stator 10 ′. As a result, the permeability of the magnetic flux in the plane of the core portion orthogonal to the axial direction directly below the coil can be improved, so that leakage of magnetic flux in the axial direction at the coil end portion is reduced, and the total magnetic flux is increased. Will be able to. As a result, it is possible to obtain a 12/8 SR motor having a flat structure with higher efficiency than the case where the entire stator 10 ′ is made of a silicon steel plate while suppressing an increase in manufacturing cost.

<Third Embodiment>
Next, a configuration example and an operation example of the flat electric motor 300 according to the third embodiment will be described with reference to FIGS. According to the flat type electric motor 300 shown in FIG. 7, the high magnetic permeability core 10a ″ is provided only on the front and back surfaces of the core portion around which the

coils

11a, 11b, and 11c are wound out of the yoke portion 10e of the stator 10 ″. Provided.

The stator 10 ″ of the electric motor 300 includes a magnetically permeable core 10b and a highly permeable core 10a ″. The permeable core 10b is the same as the permeable core 10b of the electric motor 100 shown in FIG. The high magnetic permeability core 10a ″ has an arc shape obtained by dividing the annular yoke portion 10e, and is fixed to the front and back surfaces of the magnetic permeability core 10b to form the core portion of the stator 10 ″. Thereafter, the

coils

10a, 11b, and 11c are wound around the yoke portion 10e of the stator 10 '' so as to surround the yoke portion 10e in the radial direction, and the electric motor 300 is manufactured.

Here, the torque characteristics of the flat motor 300 will be described with reference to FIG. In this embodiment, the highly permeable core 10a ″ is provided only in the core portion around which the

coils

11a, 11b, and 11c are wound out of the yoke portion 10e of the core portion of the stator 10 ″. In the torque waveform example shown in FIG. 8, the inner rotor portion 1a has an inner diameter Di of 140 mm, the outer rotor portion 1b has an outer diameter Do of 349.2 mm, the magnetically permeable core 10b of the stator 10 ″ is made of a silicon steel plate, This is a torque characteristic of the flat electric motor 300 when the thickness T is 30 mm, the highly permeable core 10a ″ is a permendur, and the thickness t is 3 mm.

The solid line shown in the figure is the torque characteristic of the electric motor 300, and the broken line is the torque characteristic when the core portion of the stator 10 "is made of only the permeable core 10b of a silicon steel plate having a thickness T of 30 mm. According to the conventional method, there is a torque peak of 35 Nm near the rotation angle of 3 ° to 4 °, and then the torque decreases rapidly. After the rotation angle of 6 °, the torque is below 30 Nm.

On the other hand, according to the method of the present invention indicated by the solid line, the torque of 35.0 Nm is maintained from the rotation angle of about 3 ° to about 8 °, and the torque becomes 30 Nm or more until the rotation angle of about 9 °. ing. The average torque is 22.9 N-m for the conventional system and 25.1 N-m for the system of the present invention, which is an improvement of 9.6% in the system of the present invention compared to the conventional system.

Thus, according to the flat electric motor 300 according to the third embodiment, the arc-shaped highly permeable core 10a ″ is wound around the

coils

11a, 11b, and 11c in the yoke portion 10e of the stator 10 ″. Used only in the vicinity of the coil end of the portion that is marked. As a result, the permeability of the magnetic flux in the plane of the core portion orthogonal to the axial direction directly below the coil can be improved, so that leakage of the magnetic flux in the axial direction at the coil end portion can be reduced. In addition, the total magnetic flux can be increased. As a result, it is possible to provide an SR motor having a flat structure that is more efficient than the case where the entire stator 10 ″ is made of a silicon steel plate while suppressing an increase in manufacturing cost.

According to the embodiment described above, the case where the flat motors 100 to 300 are SR motors has been described. However, the present invention is not limited to these, and SR motors having other configurations including linear motors, The motors 100 to 300 may be permanent magnet synchronous motors.

The present invention is extremely suitable when applied to a switched reluctance motor, a permanent magnet synchronous motor, or the like having a stator whose radial dimension is larger than the axial dimension.

1 Rotor 1a Inner rotor part 1b Outer rotor part 1c Connecting plate (base)
2 Inner segment core 3 Outer segment core 4 Rotating shaft 4a One end 4b

Other end

10, 10 ', 10 "

Stator

10a, 10a', 10a" High permeability core (shield member)
10b Magnetically permeable core 10c Inner teeth 10d Outer teeth

10e Yoke part

11a, 11b,

11c Coil

100, 200, 300 Flat type electric motor

Claims

A rotor with a shaft;
A core portion having a large radial dimension perpendicular to the axial direction relative to the axial dimension parallel to the rotor axis, and generating a magnetic field by energizing a coil wound around the core portion A stator that transmits electromagnetic force to the rotor to give a rotational torque,
An electric motor provided with a shield member having high magnetic permeability and a large saturation magnetic flux density in the vicinity of a coil end of a core portion of the stator and at least in the core portion including immediately below the coil.
2. The electric motor according to claim 1, wherein the shield member is provided on the entire surface of at least one of the front and back of the core portion of the stator orthogonal to the axial direction.
The core portion of the stator has a yoke portion;
The electric motor according to claim 2, wherein the shield member is provided only in a yoke portion of the stator.
The electric motor according to claim 2, wherein the shield member is provided only in the core portion around which the coil is wound.
The electric motor according to any one of claims 1 to 4, wherein a permendur is used for the shield member.
The electric motor according to any one of claims 1 to 5, wherein the electric motor is a switched reluctance motor.