WO2019110173A1

WO2019110173A1 - Rotor or stator of an electric machine

Info

Publication number: WO2019110173A1
Application number: PCT/EP2018/078112
Authority: WO
Inventors: David Philipp Morisco
Original assignee: Robert Bosch Gmbh
Priority date: 2017-12-06
Filing date: 2018-10-15
Publication date: 2019-06-13
Also published as: DE102017222056A1

Abstract

The present invention relates to a machine component of an electric machine (3), in particular rotor (1) or stator (10), comprising a main body (2), which has a stack of individual laminations (4) and recesses (6) for receiving permanent magnets (7), wherein, between the main body and the permanent magnets (7), there is provided in each case one electric insulation (5) which prevents an electrical connection between the laminations (4) of the main body (2) via one of the permanent magnets (7), characterized in that the electric insulation (5) comprises a magnetically soft composite material.

Description

description

title

Rotor or stator of an electric machine

State of the art

The present invention relates to a rotor or stator of an electrical machine. Furthermore, the invention relates to an electrical machine comprising such a rotor and / or stator. The rotor or stator can accommodate a permanent magnet and is opposite to the

Permanent magnets advantageously electrically isolated.

Three-phase machines with permanent magnets are known from the prior art. Such electrical machines enable high torques and high power densities. In general, the machines within the literature can be divided into two categories, internal rotor (rotor inside the stator) and external rotor (rotor outside the stator). Machine parts which concentrate the magnetic flux, in particular the stator or the rotor, are constructed of stacked electric sheets. The magnets, which are mainly installed in the rotor, are made of sintered rare earth materials, which have a high electrical conductivity.

Usually, the stacked electrical sheets are electrically isolated from each other. Time-varying magnetic fields produce eddy currents, which thus can not flow between the individual sheets. Rather, eddy currents can occur only within the individual sheets. By touching the magnets with the electrical steel stacks, however, there is a risk that the individual sheets are short-circuited and thus eddy currents flow through the magnets and thereby can be distributed in all electrical panels. This results in a significantly increased loss in the operation of the electric machine. An electrical insulation between magnet and

Although electrical steel suppresses the eddy currents, but usually also increases the magnetic resistance, which in turn brings a reduction in the performance of the electric machine with it. DE 10 2010 026 263 A1 is known in particular from the prior art. This document describes a stator of an electric machine made entirely of a magnetically conductive composite material. Such a manufacturing method has advantages in terms of eddy current behavior, but is expensive and expensive. In the cited document is the

Manufacturing process mainly chosen because a complicated stator geometry is present, which can not be achieved by stacking individual sheets.

Disclosure of the invention

The machine component according to the invention, in particular a rotor or stator, has a base body which can be manufactured simply and with little effort by means of a sheet stack. Thus, the rotor or stator does not differ from conventional rotors or stators in terms of its method of manufacture. It is merely provided in addition to the permanent magnet electrical insulation, which separates the permanent magnet of the main body and at the same time ensures a magnetic conductivity. Thus, in particular a short circuit of the sheets is prevented by the magnet, while at the same time a magnetic flux is not affected within the electrical machine. Thus, no power of the electric machine is lost.

The machine component according to the invention of an electrical machine, which is in particular a rotor or a stator, comprises a main body and an electrical insulation. The main body comprises a stack of individual sheets.

The sheets are in particular electrical sheets. The main body also has at least one recess. In the recess of the permanent magnet can be used. If the base body has a plurality of recesses, it is provided, in particular, that at least one permanent magnet can be inserted into a respective recess. In a recess and a plurality of permanent magnets can be used. The recess advantageously extends through all the sheets of the stack.

At least one permanent magnet is attached to the base body. For this purpose, it is provided in particular that the at least one permanent magnet protrudes through the individual sheets of the main body. Due to the electrical insulation is a prevents electrical contact between the permanent magnet and the base body. In this way it is prevented that the permanent magnet can short-circuit the base body, in particular an electrical short circuit between the individual sheets is prevented by the permanent magnet. Thus, an electrical connection of the sheets is prevented by one of the permanent magnets.

Furthermore, it is provided that the electrical insulation a

soft magnetic composite material includes. As a result, the electrical insulation is magnetically conductive, which is why a magnetic field is forwarded almost unaffected. This way can be effective

To combat eddy currents, while at the same time no loss of power of the electric machine is present, since the magnetic flux is not affected or close to within the electric machine.

The dependent claims have preferred developments of the invention to the content.

Advantageously, the electrical insulation is arranged in the recess. This ensures that the permanent magnet has no contact with the main body. In this way, the short circuit of the individual sheets is prevented by the permanent magnet safely and reliably.

It is particularly advantageously provided that the recess has a first region and a second region. The first area connects to the second area. Furthermore, it is provided that the first area serves to receive the permanent magnet. At the same time it is provided that in the second region, the electrical insulation is attached. In particular, the first region thus corresponds to a conventional recess, as is already present in electrical machines, in particular in rotors, according to the prior art. The second region thus represents an extension of the first region in order to be able to absorb the electrical insulation in addition to the permanent magnet. Because the first region adjoins the second region, it is ensured that a reliable separation of the main body and permanent magnet can be achieved by the electrical insulation. Furthermore, it is particularly advantageous that the first region extends between two second regions. Thus, the permanent magnet can be framed by the electrical insulation. In this way, said complete separation between the base body and the permanent magnet

advantageously achievable. At end faces, where no second region surrounds the first region, the recess is preferably larger than the

Permanent magnet, whereby it is achieved that there is no contact between the base body and permanent magnet here.

If the electrical insulation is used in the rotor, then a cross-section of the electrical insulation can be found for each level of each sheet. This corresponds in particular to that part of the electrical insulation which is present within the individual sheet. Said cross-section has outer edges, which rest exclusively on the permanent magnet or on the sheet. Thus, the electrical insulation is advantageously on such

Outside surfaces where the electrical insulation is not on the

Permanent magnet is applied, completely guided by the body. Therefore, a secure and reliable hold of the electrical insulation is ensured within the body.

The individual sheets are advantageously electrically isolated from each other. In particular, the sheets are made of electrical steel and separated from each other during stacking by electrical insulation. At the same time, the sheets, in particular all the sheets, are electrically isolable by the electrical insulation with respect to the permanent magnet. In this way, it is completely prevented that an electrical contact can occur between the individual sheets. Thus, on the one hand prevented by the electrical insulation of the sheets against each other that eddy currents can flow between the individual sheets, while can be prevented by the electrical insulation that eddy currents flow through the permanent magnet between the individual sheets. In this way, the occurrence of eddy currents is difficult or prevented. Thus, a loss in the operation of the electric machine is minimized.

The soft magnetic composite material of the electrical insulation advantageously comprises soft magnetic properties having particles, in particular a ferromagnetic powder. The particles are electric coated insulating coating. Thus, the electrical insulation has a high electrical resistance, which is to prevent

Eddy currents is used, which can flow between the permanent magnet and the individual sheets. At the same time a high magnetic conductivity is achieved, so that a magnetic flux within the rotor or stator and thus within the electrical machine or is almost not affected.

In this way it is achieved that eddy currents can be effectively combated, while otherwise no power loss of the electric machine occurs. The particles having soft magnetic properties comprise in particular iron and / or at least one iron-containing alloy.

Advantageously, the permanent magnets each have two

opposite end faces on. The end faces are enclosed in particular by four further, in particular smaller, sides. The electrical insulation is provided in each case on the end faces of the permanent magnets.

Advantageously, the electrical insulation is provided as a coating of the end faces. The permanent magnets are each pressed on their insulated end faces in the associated recess with a predetermined excess. This is a simple and low-effort installation of

Machine component achieved, as well as a secure and reliable hold of the permanent magnet is ensured in the recess of the main body of the machine component. In the recesses are particularly advantageous means, in particular recesses provided to achieve a certain position of the respective permanent magnet in the associated recess.

The invention further relates to an electrical machine. The electric machine comprises a machine component as described above.

In particular, the electric machine comprises a rotor and a stator, wherein the rotor and / or stator is as described above. Thus, eddy currents are combated in the electric machine while at the same time

Power loss of the electric machine due to the measures against eddy currents does not occur.

Particularly advantageous is provided that a permanent magnet in a

Recess of the rotor or stator is inserted. Said permanent magnet is separated from the rotor or stator and in particular electrically insulated. On This way, a short circuit between the sheets of the rotor or stator and the permanent magnet is prevented. Thus, the occurrence of

Eddy currents difficult. Since the electrical insulation is soft magnetic as described above, a magnetic flux within the electric machine is not disturbed by the electrical insulation.

Finally, it is advantageously provided that all the permanent magnets of the electric machine are electrically insulated from the sheets of the rotor or stator by the electrical insulation. Thus, at no single point within the electrical machine, in particular within the rotor or stator, a short circuit between the sheet and the permanent magnet allows. In this way, it is ensured that an occurrence of eddy currents within the entire electrical machine is difficult or prevented.

Brief description of the drawings

Hereinafter, embodiments of the invention will be described in detail with reference to the accompanying drawings. In the drawing is:

Figure 1 is a schematic representation of an electrical machine

according to an embodiment of the invention,

Figure 2a shows a first alternative embodiment of the rotor of

electric machine according to the embodiment of the invention,

Figure 2b shows a second alternative embodiment of the rotor of

electric machine according to the embodiment of the invention,

Figure 2c shows a third alternative embodiment of the rotor of

electric machine according to the embodiment of the invention,

Figure 2d shows a fourth alternative embodiment of the rotor of

electric machine according to the embodiment of the invention, and Figure 2e shows a fifth alternative embodiment of the rotor of

electric machine according to the embodiment of the invention.

Embodiments of the invention

FIG. 1 shows schematically an electrical machine 3 in accordance with FIG

Embodiment of the invention. The electric machine 3 comprises a rotor 1 and a stator 10. The rotor 1 can be driven by the stator 10, whereby the rotor 1 is rotatable about a rotation axis 100. A drive takes place while a magnetic flux within the electric machine. 3

The rotor 1 comprises a main body 2, which has a stack of individual sheets 4. The individual sheets 4 are in particular punched parts and off

Manufactured electrical sheet. By stacking the individual sheets 4 is the

Basic body 2 simple and inexpensive to produce.

The individual sheets 4 are electrically isolated from each other. In this way, it is prevented that eddy currents can flow between the individual sheets 4. Thus, an occurrence of eddy currents is possible only within the individual sheets 4, which already leads to a significant reduction in the occurrence of eddy currents.

In addition, the main body 2 has a plurality of recesses 6. Each of the recesses 6 serves to receive in each case a permanent magnet 7. The recesses 6 extend in particular along the

Rotation axis 100 through all the sheets 4 of the main body 2. Likewise, the permanent magnet 7 advantageously extends at least through all the sheets 4 along the axis of rotation 100th

By inserting the permanent magnets 7, which are usually made of electrically conductive rare earths, there is the danger that a short circuit between the individual sheets 4 is formed. In order to avoid such a short circuit, each permanent magnet 7 is separated from the base body 2 by an electrical insulation 5. The electrical insulation 5 is made of a soft magnetic composite material. At the same time is the electrical insulation 5 electrically insulating formed. In particular, it is provided that the composite particles with soft magnetic

Features. The particles have an electrically insulating

Coating on. Due to the soft magnetic properties of the particles, the magnetic conductivity is reached. This ensures that the electrical insulation 5 establishes electrical insulation between the base body 2 and the permanent magnet 7, while at the same time a magnetic flux within the electrical machine 3 is not influenced by the electrical insulation 5. The particles comprise in particular iron and / or at least one iron-containing alloy.

In the exemplary embodiment shown in FIG. 1, a permanent magnet 7 is arranged in each recess 6. Also within the recess 6, the electrical insulation 5 is arranged. For this purpose, the recess has a first region 8, which is provided for receiving the permanent magnet 7. Likewise, the recess 6 has a second region 9, the to

Recording the electrical insulation 5 is provided. In this way, it is achieved that both the electrical insulation 5 and the permanent magnet 7 can be arranged safely and reliably in the recess 6.

Two second regions 9 particularly advantageously frame a first region 8. Thus, the permanent magnet 7 is surrounded by the electrical insulation 5.

This leads to a safe and reliable separation of base body 2 and permanent magnet 7. At the same time, the electrical insulation 5 and the permanent magnet 7 are securely mounted within the recess 6.

In the cross section shown in FIG. 1, the electrical insulation 5 thus has outer edges which are exclusively in contact either with the main body 2 or the permanent magnet 7. Thus, the electrical insulation is completely integrated into the main body 2. As a result, optimum magnetic flux is ensured within the electric machine 3. At the same time, the electrical insulation 5 is safe and reliable in the

Main body 2 held. By the concern to the permanent magnet 7 also the permanent magnet 7 is securely and reliably fixed within the body 2. At the same time said electrical insulation between the base body 2 and permanent magnet 7 is reached. FIG. 2 shows five different alternatives of the construction of the rotor 1. Only one segment of the rotor 1 is shown in FIG.

In a first alternative shown in Figure 2a, two recesses 6 are present, which are radially offset with respect to the axis of rotation 100. This means that the one recess 6 radially outward than the second

Recess 6 is attached. In each recess 6 also three permanent magnets 7 are mounted, wherein the permanent magnets 7 is framed by the electrical insulation. In this way, a high number of permanent magnets within a rotor segment is present. At the same time it is ensured by the measures described above that no short circuit between the individual sheets 4 of the main body 2 can occur. In particular, by providing two basic bodies 5 per permanent magnet 7 it is ensured that all permanent magnets 7 are mounted in an electrically insulated manner from the individual metal sheets 4 within the main body 2.

The second alternative shown in Figure 2b comprises a recess 6 per segment of the rotor 1. In each recess 6, two permanent magnets 7 are arranged. Thus, compared to the first alternative, which is shown in Figure 2a, the number of permanent magnets 7 is reduced. As described above, the electrical insulation 5 framing each permanent magnet 7, whereby the

Permanent magnet 7 is safe and reliable electrically isolated from the individual sheets 4 of the main body 2 of the rotor 1.

In the third alternative, as shown in FIG. 2c, two are again

Recesses 6 available. In this alternative, the recesses 6 have a curvature. Again, it is provided that one of the recesses 6 is arranged radially outside the other recess 6. In any case, it is provided that each permanent magnet 7 is framed by the electrical insulation 5.

In a fourth alternative, as shown in Figure 2d, it is provided that the permanent magnet 7 is fixed radially on the outside of the main body 2 of the rotor 1. Thus, no recess 6 is present. Rather, the

Permanent magnet 7 is applied from radially outside to the base body 2. Nevertheless, an electrical insulation between the base body 2 and To ensure permanent magnet 7, the electrical insulation 5 is present.

The electrical insulation 5 can either be arranged in a separate recess within the rotor 1, so that the attachment of the

Permanent magnet 7 can be done analogously to known rotors from the prior art. It is also possible, before applying the

Permanent magnet 7 to provide the main body 2 of the rotor 1 radially from the outside with the electrical insulation 5. Also in this case is the electrical insulation 5 between the permanent magnet 7 and the base body 2, whereby an electrical insulation between the sheet 4 and the permanent magnet 7 is reached.

A fifth alternative is shown in FIG. 2e. Here, the recess 6 is adapted to special needs of the electric machine 3. Again, however, it can be seen that the recess 6 comprises a first region 8, which is framed by two second regions 9. Thus, the permanent magnet 7 is framed by the electrical insulation 5, which ensures that the permanent magnet 7 is reliably separated from the individual sheets 4 of the base body 2 and thus is electrically isolated from this. An occurrence of eddy currents is thus again safely and reliably prevented.

Claims

claims

1. Machine component of an electrical machine (3), in particular rotor (1) or stator (10), comprising a base body (2) having a stack of individual sheets (4) and recesses (6) for receiving

Permanent magnet (7), wherein between the base body and the permanent magnet (7) each having an electrical insulation (5) is provided which prevents electrical connection between the sheets (4) of the base body (2) via one of the permanent magnets (7) characterized in that the electrical insulation (5) has a

soft magnetic composite material includes.

2. Machine component according to claim 1, characterized in that the electrical insulation (5) in the recess (6) is arranged.

3. Machine component according to claim 2, characterized in that the recess (6) has a first region (8) and a first region (8) adjoining the second region (9), wherein the first region (8) for receiving the permanent magnet (7) and wherein in the second region (9) the electrical insulation (5) is mounted.

4. Machine component according to claim 3, characterized in that the first region (8) extends between two second regions (9).

5. Machine component according to one of the preceding claims,

characterized in that outer edges of a cross section of the electrical insulation (5) in the plane of each sheet (4) rest exclusively on the permanent magnet (7) or on the sheet (4).

6. Machine component according to one of the preceding claims,

characterized in that the sheets (4) are electrically isolated from each other and by the electrical insulation (5) relative to the

Permanent magnets (7) are electrically isolated.

7. Machine component according to one of the preceding claims, characterized in that the soft magnetic composite material comprises soft magnetic properties having particles which are coated with an electrically insulating coating.

8. Machine component according to claim 7, characterized in that the soft magnetic properties having particles iron and / or at least one iron-containing alloy.

9. Machine component according to one of the preceding claims,

characterized in that the permanent magnets (7) each have two opposite end faces, that of four further,

in particular smaller, sides are enclosed, wherein the electrical insulation (5) is provided respectively at the end faces of the permanent magnets (7), in particular as a coating, wherein the

Permanent magnets (7) are each pressed on their insulated end faces in the associated recess (6) with a predetermined excess.

10. Machine component according to one of the preceding claims,

characterized in that in the recesses (6) means,

in particular recesses are provided in order to achieve a specific position of the respective permanent magnet (7) in the associated recess (6).

1 1. Electrical machine (3) comprising a machine component according to

one of the preceding claims.

12. Electrical machine (3) according to claim 8, characterized in that a permanent magnet (7) is inserted into the recess (6) of the machine component.

13. Electrical machine (3) according to claim 9, characterized in that all permanent magnets (7) of the electric machine (3) relative to the sheets (4) of the rotor (1) or stator (10) by the electrical insulation (5) electrically are isolated.