WO2009071064A1

WO2009071064A1 - Electric motor having partial surge protection and method for the production thereof

Info

Publication number: WO2009071064A1
Application number: PCT/DE2008/002007
Authority: WO
Inventors: Martin Hotop; Eckhard Wendorff
Original assignee: Ina - Drives & Mechatronics Gmbh & Co. Ohg
Priority date: 2007-12-05
Filing date: 2008-12-02
Publication date: 2009-06-11
Also published as: DE102007058821A1

Abstract

The invention relates to an electric motor having an iron-free or low-iron construction, comprising as a first magnetic-field-producing element at least one electromagnetic coil, the magnetic field of which interacts with the magnetic field of a second magnetic-field-producing element, wherein a first insulation layer is provided on at least one side of the at least one electromagnetic coil facing the second magnetic-field-producing element. The invention further relates to a method for the production of an electric motor having an iron-free or low-iron structure. In order to prevent a partial surge over the operating air gap, a first conductive layer is located on a side of the first insulation layer facing the second magnetic-field-producing element, wherein a first region of the first conductive layer extending substantially over the entire first conductive layer has housing voltage.

Description

Name of the invention

Electric motor with partial discharge protection and method for its production

description

Field of the invention

The invention relates to an electric motor with a low-iron or low-iron construction, comprising as a first, magnetic field generating element at least one electromagnetic coil whose magnetic field with the magnetic field of a second magnetic field generating element interacts with at least one of the second , a magnetic field generating element facing side of the at least one electromagnetic coil is a first insulating layer. The invention further relates to a method for producing an electric motor with an ironless or low-iron construction. Background of the invention

Ironless or low-iron electric motors are available both as permanent magnet synchronous motors and as induction motors. The terms "one-less" and "low-iron" respectively designate the coil system used in such an electric motor, which is self-supporting wound in such electric motors without iron core and often soaked in synthetic resin.

Electric motors with an iron-free or low-iron primary part or rotor therefore have a reduced moment of inertia, can therefore accelerate faster and are therefore preferably used in the so-called pick-and-place region, e.g. in semiconductor manufacturing or electronics assembly.

An ironless linear motor is e.g. from US 2005/0012404 A1 and an ironless rotary motor, e.g. known from US 6,674,214 B1.

If permanent magnet synchronous motors or asynchronous motors are operated directly on the AC voltage network, they have a fixed nominal speed which depends on their number of poles and on the mains frequency. In order to enable a variable speed, in these electric motors, the frequency of the applied AC voltage must be changed. For this purpose, a frequency converter is used, which first generates a DC voltage from a predetermined by the AC voltage AC voltage with a certain frequency, the so-called DC link voltage. From this, the frequency converter generates an alternating voltage with the desired frequency in a further step.

The step for generating an alternating voltage from the intermediate circuit voltage is effected for example by a pulse width modulation. The DC link voltage is pulsed at constant intervals on the electromotive tor applied (switching operation), wherein the pulse width and the associated pulse pause is varied in order to achieve the desired sinusoidal AC voltage of certain frequency. The ratio of pulse width to pulse interval can vary from virtually 0% to 100%. The inductance of the connected electric motor finally ensures that the current flow is smoothed.

In order to already produce the smoothest possible course of the sinusoidal AC voltage, a correspondingly high frequency of the switching operations is selected. The frequency is e.g. in the range of 3 - 8 kHz.

However, with each switching operation, voltage spikes occur that can reach 2 to 2.5 times the DC link voltage.

At each voltage spike triggered by a switching action, above the working air gap, e.g. in a permanent magnet synchronous motor across the air gap between the coil and the permanent magnet, a very high voltage.

In conventional ironless or low-iron electric motors, these voltage peaks have a disadvantageous effect. In contrast to iron-based electric motors, in which the coils are embedded in grooves of the iron core, and in which only about 10% of the coil surface faces the working air gap, this proportion is much higher for ironless or low-power electric motors. The risk of sudden voltage reduction (breakdown) between the coil and the spaced apart by the working air gap component is thus greater in ironless or low-iron electric motors.

To prevent penetration at the working air gap, located on the side of the coil, which faces the working air gap, an insulating layer. Seen visually, they form with the insulation layer and the Working air gap two capacitors connected in series. The capacitor, which represents the insulating layer, has a relatively large permittivity number (relative dielectric constant). In the case of an epoxide layer, for example, this is approximately ε _r = 6. By contrast, the condenser, which represents the working air gap, has a relatively low permittivity of almost ε _r = 1. Although the insulating layer on the coil prevents strike-through, however, the air is ionized in the working air gap and there is a potential equalization between the surface of the insulating layer, which faces the working air gap, and the component of the electric motor, which is spaced from the coil by the working air gap, eg the permanent magnet of a permanent magnet synchronous motor. This potential equalization, the so-called partial discharge, is repeated at the switching frequency of the frequency converter and sparking occurs between the insulating layer of the coil and the component of the electric motor, which is spaced from the coil by the working air gap.

This sparking is disadvantageous for several reasons. It permanently leads to damage to the insulation layer on the coil and thus increases the risk of breakdown. In any case, the insulating layer must be designed at least correspondingly resistant.

The electrostatic discharge by means of ionization of the air also has a negative effect on the electromagnetic compatibility (EMC) of the electric motor.

Finally, the ionization takes place in the spectrum of UV light. Thus, it must be ensured that persons are protected accordingly.

It is known that printed circuit board material consists of an insulating carrier material (base material), e.g. of glass fiber mats soaked in epoxy resin, on which a conductive layer, i.d.R. made of copper, is applied.

Printed circuit board material can contain several superimposed conducting and isolating have onsschichten and is known for example from DE 19800691 A1 or from http://de.wikipedia.org/wiki/Leiterplatte (as of 29.11.2007).

Object of the invention

The invention has for its object to provide a generic electric motor and a method for its production, whereby the disadvantages of the known from the prior art electric motors are overcome in a simple and cost-effective manner.

Summary of the invention

The solution of this object is achieved according to the invention in that on a second, a magnetic field generating element side facing the first insulating layer is a first conductive layer, wherein a first region of the first conductive layer, which extends substantially over the entire first conductive layer, housing potential ,

The solution of this object is further achieved by a method for producing an electric motor with an ironless or low-iron construction, comprising the steps:

- Circulation of a first consisting of an electromagnetic coil, a magnetic field generating element with an insulating means, so that after its curing on at least one surface of the electromagnetic coil, which faces a second magnetic field generating element during operation of the electric motor at least forms an insulating layer, Applying a conductive layer on the areas of the at least one insulating layer, which face the second, a magnetic field generating element in the operation of the electric motor, and

- Contacting the conductive layer such that a first region which extends substantially over the entire first conductive layer has housing potential.

Introducing a first, a magnetic field generating element consisting of an electromagnetic coil and at least one plate consisting of printed circuit board material in a mold, wherein the at least one plate is positioned such that a conductive layer of the at least one plate during operation of the electric motor a second, a magnetic field facing generating element and

Pour out the mold with an insulating agent.

Under insulation layer according to the invention is a layer to understand, which consists of a commercially available, electrical insulation material. The conductive layer, in turn, may consist of a metallic conductor, or of an electrical resistance material having a resistivity in the range of one order of magnitude greater than a comparable electrical conductor.

The first conductive layer according to the invention is now intended to have housing potential in a first region, which extends substantially over the entire first conductive layer. Because the surface of the second, a magnetic field generating element also has housing potential, is above the working air gap no potential difference more. Thus, there is no ionization of the air in the working air gap.

Although the at least one electromagnetic coil and the second element generating a magnetic field are thus still separated from one another by two capacitors (first insulation layer and working air gap). However, since housing potential is present across the condenser, which represents the working air gap, partial discharge can no longer occur despite the low permittivity number of the working air gap.

Without reducing the efficiency of the electric motor, the disadvantages arising from the partial discharge are thus overcome in a simple, cost-effective manner according to the invention.

It is sufficient according to the invention that the first region of the first conductive layer has almost housing potential. Slight potential differences between the first conductive layer and the surface of the second magnetic field generating element are acceptable as long as this can not lead to partial discharges.

The effects according to the invention become more pronounced the greater the proportion of the first region on the first conductive layer. Therefore, the first region corresponds substantially to the entire first conductive layer. The portions of the first conductive layer which do not belong to the first region are preferably located at the edge thereof in order to exclude partial discharges as far as possible in these regions. These areas can be used for contacting electrical components.

According to a preferred embodiment, at least one further insulating layer and a further conductive layer are located between the first insulating layer and the first conductive layer, wherein all insulation and insulation layers Guide layers are arranged alternately. By alternating arrangement of insulating and conductive layers is meant that a layer structure is present in which insulating and conductive layers are alternately superimposed. The at least one further insulation layer and the at least one further conductive layer can serve to provide even better protection against partial discharges. However, since protection against partial discharges is already possible in principle by the first insulation layer and the first conductive layer, the at least one further conductive layer can also serve additional purposes, for example the contacting of electrical components. In this case, the at least one further conductive layer need not have housing potential. Preferably, the insulation layer facing the at least one electromagnetic coil, ie the first insulation layer, is made thicker than the remaining insulation layers. In this case, the first insulation layer has the task of taking over the insulation between the at least one electromagnetic coil and the second element producing a magnetic field alone, ie it represents a main insulation. The at least one further insulation layer then only has the task to ensure an insulation between two adjacent conductive layers, and may be configured according to thin depending on the existing potential differences of these conductive layers.

According to a preferred embodiment, exactly one further insulation layer and one further conductive layer are located between the first insulation layer and the first conductive layer. This is a simple and cost-effective design, which on the one hand prevents partial discharges through the first conductive layer and, on the other hand, a further conductive layer, e.g. provides for contacting electrical components.

According to a preferred embodiment, a first region of the at least one further conductive layer has housing potential. Even if the at least one further conductive layer for contacting electrical

Components is used, it is usually not necessary for the to use at least one other conductive layer. Rather, a very large part of the at least one further conductive layer, namely the first region, further increase the protection against partial discharges by having this region of housing potential.

According to a preferred embodiment, in the case of the at least one further conductive layer, the first housing potential-containing region of this conductive layer extends essentially over the entire conductive layer. The areas of the at least one further conductive layer which may be necessary for contacting electrical components are generally very small, which is why a large part of these conductive layers can contribute to the improvement of the partial discharge protection, i. Can have housing potential. Preferably, in the case of the at least one further conductive layer, the region which does not have housing potential does not face electromagnetic coils. The risk of reducing the partial discharge protection through these areas is thus minimized.

According to a preferred embodiment, in at least one conductive layer, the first region of this conductive layer extends over the entire conductive layer. If no contacting of electrical components by these at least one conductive layer is to take place, the partial discharge protection can be further improved in this way.

According to a preferred embodiment, the first region of the first conductive layer extends over the entire first conductive layer and the first region of the one further conductive layer extends substantially over the entire one further conductive layer. In a construction with two conductive layers and two insulating layers, this makes optimum protection against partial discharges possible, wherein at the same time, for example, the contacting of electrical components by means of a further conductive layer is possible. According to a preferred embodiment, the at least one conductive layer, the first region of which does not extend completely over the entire conductive layer, comprises contact means for contacting the at least one electromagnetic coil, contacting means for contacting, on a second region of this conductive layer which is outside the first region of sensors and / or sensors. Such contacting electrical components or training of sensors has a very compact structure. In this case, the complete power supply of the at least one electromagnetic coil can take place via the second region. Sensors can be used, for example, to detect the magnetic field strength, the temperature or the path or the rotational speed. As a rule, the sensors consist of standard elements which are contacted via the conductive layer.

According to a preferred embodiment, the contact means consist of solderable pads. Such pads or pads are known in the electrical engineering field to contact boards, wherein their solderability allows to attach the required connections.

According to a preferred embodiment, at least one conductive layer consists of a metallic layer, in particular of a copper layer. In this case, recourse can be had to methods already known for applying corresponding surfaces, e.g. Vapor deposition or galvanizing. With these methods, even surfaces of irregular shape can be easily coated with a conductive layer.

According to a preferred embodiment, at least one insulating layer and an adjacent conductive layer form a board made of a printed circuit board material. Circuit board material consists of an insulating carrier material (base material), for example of glass fiber mats soaked in epoxy resin, on which a conductive layer, usually of copper, is applied. Printed circuit board material is available in various designs, eg layer thicknesses of the carrier material, as a standard article in the electrical engineering sector. The advantage here is that with printed circuit board material a certain dielectric strength is ensured. This simplifies the design of the insulation layers according to the invention, since these corresponding values can be used. This is advantageous, in particular, over a production method in which the at least one insulation layer is formed by the application of epoxy resin. The reason is that the dielectric strength of such manufactured insulation layers is difficult to determine due to voids in the epoxy resin layer. This reduction in dielectric strength due to local manufacturing defects is unknown in circuit board material; Printed circuit board material thus represents a layer with constant permeability. According to the invention, only certain adjacent insulating layers and conductive layers can form a plate made of a printed circuit board material, while further conductive layers are produced, for example, by vapor deposition of a conductive material.

According to a preferred embodiment, at least two pairs of adjacent insulating layers and conductive layers form at least one board of printed circuit board material. If at least two insulating and two conductive layers are formed by printed circuit board material, multiple sheets of printed circuit board material may be used, which may be bonded together or with other insulating or conductive layers. The advantage here is that very easily different arrangements of insulation and conductive layers are possible by already existing plates of printed circuit board material. For example, already available printed circuit boards with specific contacts or sensors can be integrated into different arrangements of insulation or conductive layers. However, it is also possible to integrate more than one pair of insulation and conductive layer in a board of printed circuit board material with a corresponding number of layers. This can lead to lower costs for corresponding quantities. According to a preferred embodiment, the thickness of the insulating layer of the at least one plate is selected so that the electric motor insulation is ensured in the region of a working air gap solely by this insulating layer. In this case, the main insulation is ensured by the insulating layer of the at least one plate.

According to a preferred embodiment, an additional insulation layer is present between the at least one electromagnetic coil and the plate facing it. Such an insulating layer may e.g. caused by the bonding of the at least one electromagnetic coil and the plate facing this.

According to a preferred embodiment, the additional insulating layer consists of a synthetic resin layer, preferably of an epoxy resin layer. If, in the manufacture of the electric motor, the at least one electromagnetic coil and the plate facing it are fixed in a mold which is subsequently filled with epoxy resin, an additional insulating layer can be formed by an epoxy resin layer.

According to a preferred embodiment, the at least one conductive layer is partially slit to reduce eddy currents. Due to the movement transverse to the field lines of the magnetic field, a voltage is induced in the conductive layers, which leads to eddy currents. The eddy currents generate a magnetic field that is opposite to their cause, that is, the voltage generating magnetic field. This creates a braking force. Furthermore, heat losses occur. These eddy current losses are greater, the larger the inner circle diameter of the conductive layers. By dividing the surface of the conductive layer into a plurality of smaller areas, the consequences of the eddy currents can therefore be contained. This division is carried out by the guide layers are slotted, ie divided into strip-shaped sections. In order for the conductive layer as a whole to continue to have housing potential, all strips are connected to one another at one end, whereby only one connection between the housing potential and the conductive layer is necessary.

According to a preferred embodiment, at least two conductive layers are at least partially stripe-shaped in order to reduce eddy currents, wherein the at least two conductive layers are slit in such a way that slots of these two conductive layers do not overlap one another.

According to a preferred embodiment, at least one conductive layer is designed to reduce eddy currents high impedance. A high ohmic resistance counteracts eddy current formation. Despite a high ohmic resistance of the at least one conductive layer this is still a much better electrical conductor with respect to the at least one insulating layer. According to a preferred embodiment, the at least one conductive layer is formed by a high-resistance material and / or a very small layer thickness.

According to a preferred embodiment, the high-resistance material has an 8 to 12-fold, in particular a 10-fold, higher specific resistance than copper. Due to the high voltages during Umrichtvorvorgänge can thereby continue to provide a partial discharge protection, while the eddy currents with relatively low voltages, approximately in the range of a few tenths of a volt, can be significantly reduced.

According to a preferred embodiment, the at least one conductive layer consists of several layers of conductive materials. For example, printed circuit board material is often constructed by one or more conductive layers of copper, each consisting of several layers. It is also possible that the conductive layer is first deposited by vapor deposition and closing is produced by electroplating. It is possible that the at least one conductive layer is formed by layers of different or the same materials.

According to a preferred embodiment, a protective layer is located on a side of the first conductive layer facing the second magnetic field generating element. This can e.g. consist of solder mask or insulating varnish and has the task to protect the first conductive layer from external influences, for. To avoid corrosion.

According to a preferred embodiment, the electric motor according to the invention is a permanent magnet synchronous motor, wherein the second, a magnetic field generating element is formed by at least one permanent magnet. In this case, it is possible for the at least one permanent magnet to be stationary in relation to an electric motor housing and for the at least one electromagnetic coil to move. Alternatively, it is possible for the at least one electromagnetic coil to be stationary with respect to an electric motor housing and for the at least one permanent magnet to move.

According to a preferred embodiment, the electric motor according to the invention is an asynchronous motor.

According to a preferred embodiment of the method for producing an electric motor with an ironless or low-iron construction, the insulation means comprises synthetic resin, preferably epoxy resin.

Brief description of the drawings

For a better understanding of the present invention, reference is made to the accompanying figures. Hereby shows: 1 shows a schematic representation of a first embodiment of the electric motor,

2 shows a schematic representation of a second embodiment of the electric motor,

3 shows a schematic representation of a third embodiment of the electric motor,

4 shows a schematic representation of a fourth embodiment of the electric motor,

5 shows a schematic representation of a fifth embodiment of the electric motor,

6 is a plan view of a partially strip-shaped slotted, rectangular conductive layer,

7 shows a plan view of a partially strip-shaped slotted, circular conductive layer

8 is a sectional view of a sixth embodiment based on a linear motor,

9 is a sectional view of a seventh embodiment based on a rotary electric motor,

10 is a sectional view of an eighth embodiment based on a rotary electric motor, and

11 is a sectional view of a ninth embodiment based on a rotary electric motor. Detailed description of the drawing

Fig. 1 shows a schematic representation of a first embodiment of the electric motor. In this case, the electric motor comprises a coil 1 which has an insulation layer 4 on a surface 3 facing a magnet 2. The insulating layer 4 corresponds to the first insulating layer and consists of an epoxy layer, which is formed when casting the coil 1 with epoxy resin. On the surface of the insulating layer 4, which faces the magnet 2, there is a conductive layer 5, which corresponds to the first conductive layer according to the invention. The conductive layer 5 is formed by a coating of the insulating layer 4 with a metallic material.

The coil 1 and the magnet 2 are spaced apart by the working air gap 6. The single insulation layer 4 represents the main insulation, i. it alone prevents penetration between the coil surface 3 and the working air gap 6 facing surface 7 of the magnet 2. The contacting of the coil 1 is not shown.

Fig. 2 shows a schematic representation of a second embodiment of the electric motor. With regard to the basic structure and matching reference numerals, reference is made to FIG. 1. This exemplary embodiment has a further insulating layer 8 and a further conductive layer 9, which are located between the first insulating layer 4 and the first conductive layer 5, wherein there is an alternating sequence of insulating and conductive layers. Again, the insulation layer 4 takes over the task of main insulation. The insulating layer 8 is intended to ensure only insulation of the conductive layers 5 and 9 and can be made correspondingly thin. In this exemplary embodiment, the conductive layer 9 is used for contacting electrical components (not shown), since the conductive layer 5 already prevents the occurrence of partial discharges above the working air gap 6. Fig. 3 shows a schematic representation of a third embodiment of the electric motor. With regard to the basic structure and matching reference numerals, reference is made to FIG. 1. The first insulating layer 4 and the first conductive layer 5 in this case form a plate 10 made of a printed circuit board material. The plate 10 is fixed on the magnet 2 facing surface 3 of the coil 1, for example by gluing. Here, the thickness of the insulating layer 4 of the plate 10 is selected so that the electric motor insulation in the region of a working air gap 6 is ensured solely by the insulating carrier material.

Fig. 4 shows a schematic representation of a fourth embodiment of the electric motor. With regard to the basic structure and matching reference numerals, reference is made to FIG. 1. On the surface 3 of the coil 1 there are two plates 11 and 12 made of printed circuit board material. In this case, the plate 11 comprises the first insulation layer 4, which represents the main insulation, and further conductive layers 13 and 15 and a further insulation layer 14. The further conductive layers represent a further improvement of the protection against partial discharges and enable the contacting of electrical components. The second plate 12 comprises, in addition to the first conductive layer 5, a further insulation layer 16.

Fig. 5 shows a schematic representation of a fifth embodiment of the electric motor. With regard to the basic structure and matching reference numerals, reference is made to FIG. 1. Here, the plate 11 comprises two insulating layers 4 and 14 and two conductive layers 5 and 13. As in the embodiment of FIG. 2, while the first conductive layer is the protection against partial discharges, while the further conductive layer 13 is at least partially used for contacting other electrical components , On the side facing the magnet 2 surface 17 of the first conductive layer 5 is a protective layer 18. It provides protection against external influences and encloses not only the surface 17 but also the sides of the plate eleventh Fig. 6 shows a plan view of a partially strip-shaped slotted, rectangular conductive layer. The conductive layer 19 can be used in a linear motor, for example according to the embodiment of FIG. 8. It has a plurality of slots 20. As a result, the inner circle diameter of contiguous surface portions of the conductive layer 19 is substantially reduced, whereby eddy current losses can be reduced. The slots 20 each extend from the lower edge of the conductive layer 19 to just before the upper edge of the conductive layer 19. As a result, housing potential can be applied to the conductive layer 19 by means of a contact point. If the conductive layer is already structured by eg conductor tracks, the use of slots can be dispensed with or the number can be reduced.

Fig. 7 shows a plan view of a partially strip-shaped slotted, circular conductive layer. The conductive layer 19 has a plurality of slots 20 which extend in a star shape. The conductive layer 19 may be incorporated in a rotary electric motor e.g. be used according to the embodiment of FIG. 8. If a plurality of conductive layers are provided, it is advantageous to provide slots on each conductive layer, if possible, and to position the slots such that the slots of two adjacent conductive layers, ie those which are only separated by an insulating layer, do not overlap one another. In rotary motors, two adjacent, circular conductive layers can be arranged rotated relative to each other.

8 shows a sectional illustration of a sixth embodiment based on a linear motor. Here, the coil 1 moves along an axis perpendicular to the plane of the drawing within two rows of magnets 2. The coil 1 is fixed to a support body 21, while the magnets 2 are connected by brackets 22 with the electric motor housing, not shown. Contacts are also not shown. The coil 1 has, in this embodiment, two sides facing the magnet 2. On each of these pages is a first insulation layer 4. On this is, in each case the Instead of this arrangement with only one insulation and only one conductive layer (corresponding to the embodiment of FIG. 1), this embodiment can also be combined, for example, with the embodiments of Figures 2-5. The first conductive layer 5 can additionally be slit according to FIG. 6.

9 shows a sectional view of a seventh embodiment based on a rotary electric motor. In this case, the carrier plate 23 of the magnets moves about the illustrated axis of rotation. By contrast, the coils 1 are firmly anchored to a corresponding holder 24. Shown again is an embodiment with only one insulation layer 4 and a conductive layer 5 according to FIG. 1. However, combinations with the exemplary embodiments according to FIGS. 2-5 can also be used. In addition, the first conductive layer 5 can additionally be slit in accordance with FIG. 7.

10 shows a sectional view of an eighth embodiment based on a rotary electric motor. Shown on the left is a sectional view in an axial plan view and on the right a sectional view along the axis AA. Here, the coil 1, the first insulating layer 4 and the first conductive layer 5 form the rotor, while the magnets 2 are firmly anchored in contrast. The electric motor is produced by the method according to the invention: The first conductive layer 5 and the first insulating layer 4 are formed by a printed circuit board. This was first produced as a strip and brought by round bending in the required, cylindrical shape. It should be noted that the resulting gap 25 should be as small as possible in order not to reduce the partial discharge protection too strong. In addition, the gap 25 can also be placed such that it is arranged between two coil segments within the coil 1. The cylindrical circuit board is now placed around the coil 1, both are placed in a mold and this ausgegos- with an insulating agent. sen. In this case, a further insulating layer between the coil 1 and the first insulating layer 4 can form. The coil 1 can in this case form either the stator or the rotor.

11 shows a sectional view of a ninth embodiment based on a rotary electric motor. In contrast to the exemplary embodiment according to FIG. 10, the coil 1 encloses the magnet 2 together with the first insulation layer 4 and the first conductive layer 5. The coil 1 can in this case form either the stator or the rotor.

LIST OF REFERENCE NUMBERS

1 coil

2 magnet 3 the surface of the coil facing the magnet

4 first insulation layer

5 first conductive layer

6 working air gap

7 of the coil facing surface of the magnet 8 more insulation layer

9 more conductive layers

10 board made of printed circuit board material

11 board made of printed circuit board material

12 plate of printed circuit board material 13 more conductive layer

14 more insulation layer

15 more conductive layers

16 more insulation layers

17 facing the magnet surface of the first conductive layer 18 protective layer

19 conductive layer

20 slots

21 carrier body

22 brackets 23 support plate

24 bracket

25 gap

Claims

claims

1. Electric motor with an iron-free or low-iron construction, comprising as a first, a magnetic field generating element at least one e- lektromagnetische coil whose magnetic field with the magnetic field of a second magnetic field generating element interacts, wherein on at least one of the second, a A first insulating layer is located on the side of the at least one electromagnetic coil facing the magnetic field generating element, characterized in that a first conductive layer is located on a side of the first insulating layer facing the second magnetic field generating element, wherein a first region of the first conductive layer extends substantially over the entire first conductive layer has housing potential.

2. Electric motor according to claim 1, characterized in that there is at least one further insulating layer and a further conductive layer between the first insulating layer and the first conductive layer, wherein all the insulating and conductive layers are arranged alternately.

3. Electric motor according to claim 2, characterized in that located between the first insulating layer and the first conductive layer exactly one more insulating layer and another conductive layer.

4. Electric motor according to claim 2 or 3, characterized in that also has a first region of the at least one further conductive layer housing potential.

5. Electric motor according to claim 4, characterized in that extends in the at least one further conductive layer of the first housing potential having region of this conductive layer substantially over the entire conductive layer.

6. Electric motor according to one of claims 1-5, characterized in that extends at least one conductive layer of the first region of this conductive layer over the entire conductive layer.

7. Electric motor according to claim 3 and 4, characterized in that the first region of the first conductive layer extends over the entire first conductive layer, and that the first region of the another one

Conductive layer extends substantially over the entire further conductive layer.

8. Electric motor according to one of claims 1-5 or 7, character- ized in that the at least one conductive layer, the first region of which does not extend completely over the entire conductive layer, lies on a second region of this conductive layer which is outside the first region, Contact means for contacting the at least one electromagnetic coil, contact means for contacting sensors and / or sensors.

9. Electric motor according to claim 8, characterized in that the contact means consist of solderable pads.

10. Electric motor according to one of claims 1-9, characterized in that at least one conductive layer of a metallic

Layer, in particular of a copper layer consists.

11. Electric motor according to one of claims 1-9, characterized in that at least one insulating layer and an adjacent conductive layer form a plate of a printed circuit board material.

12. Electric motor according to one of claims 2-9, characterized in that at least two pairs of adjacent insulating layers and conductive layers form at least one plate of a printed circuit board material.

13. Electric motor according to claim 11 or 12, characterized in that the thickness of the insulating layer of the at least one plate is selected so that the electric motor insulation in the region of a working air gap is ensured solely by this insulating layer.

14. Electric motor according to one of claims 11 - 13, characterized in that between the at least one electromagnetic coil and the plate facing this an additional insulation layer is present.

15. Electric motor according to claim 14, characterized in that the additional insulating layer consists of a synthetic resin layer, preferably of an epoxy resin layer.

16. Electric motor according to one of claims 1 - 15, characterized in that at least one conductive layer is at least partially slotted strip to reduce eddy currents.

17. Electric motor according to one of claims 2 - 15, characterized in that at least two conductive layers are at least partially slit striped to reduce eddy currents, wherein the at least two conductive layers are slotted in such a way that slots of these two conductive layers do not overlap.

18. Electric motor according to one of claims 1-17, characterized in that at least one conductive layer is designed to reduce eddy currents high impedance.

19. Electric motor according to claim 18, characterized in that the at least one high-resistance conductive layer is formed by a high-coherent material and / or a very small layer thickness.

20. Electric motor according to claim 19, characterized in that the high-resistance material has an 8 to 12-fold, in particular a 10-fold, higher resistivity than copper.

21. Electric motor according to one of claims 1 to 20, characterized in that at least one conductive layer consists of several layers of conductive materials.

22. Electric motor according to one of claims 1 - 21, characterized in that there is a protective layer on a second, a magnetic field generating element side facing the first conductive layer.

23. Electric motor according to one of claims 1 - 22, characterized in that it is a permanent magnet synchronous motor, wherein the second, a magnetic field generating element is formed by at least one permanent magnet.

24. Electric motor according to claim 23, characterized in that, with respect to an electric motor housing, the at least one permanent magnet is fixedly arranged and the at least one electromagnetic coil moves.

25. Electric motor according to claim 23, characterized in that, with respect to an electric motor housing, the at least one electromagnetic coil is fixedly arranged and the at least one permanent magnet moves.

26. Electric motor according to one of claims 1 - 22, characterized in that it is an asynchronous motor.

27. A method of manufacturing an electric motor having an ironless or low iron construction, comprising the steps of:

Circulation of a first, a magnetic field generating element consisting of an electromagnetic coil with an insulating agent, so that after curing on at least one surface of the electromagnetic coil, which faces a second magnetic field generating element during operation of the electric motor, forming at least one insulating layer .

Applying a conductive layer on the areas of the at least one insulating layer, in the operation of the electric motor to the second, a

Are facing magnetic field generating element, and Contacting the conductive layer such that a first region which extends substantially over the entire first conductive layer has housing potential.

28. A method of manufacturing an electric motor having an ironless or low iron construction, comprising the steps of:

Pour out the mold with an insulating agent.

29. A method for producing an electric motor with an ironless or low-iron construction according to claim 27 or 28, character- ized in that the insulating means synthetic resin, preferably epoxy resin, includes.