EP1421664A1 - Electric motor excited by permanent magnets - Google Patents

Electric motor excited by permanent magnets

Info

Publication number
EP1421664A1
EP1421664A1 EP02717982A EP02717982A EP1421664A1 EP 1421664 A1 EP1421664 A1 EP 1421664A1 EP 02717982 A EP02717982 A EP 02717982A EP 02717982 A EP02717982 A EP 02717982A EP 1421664 A1 EP1421664 A1 EP 1421664A1
Authority
EP
European Patent Office
Prior art keywords
rotor
electric motor
permanent magnets
recesses
motor according
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Withdrawn
Application number
EP02717982A
Other languages
German (de)
French (fr)
Inventor
Volker Bosch
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
Robert Bosch GmbH
Original Assignee
Robert Bosch GmbH
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by Robert Bosch GmbH filed Critical Robert Bosch GmbH
Publication of EP1421664A1 publication Critical patent/EP1421664A1/en
Withdrawn legal-status Critical Current

Links

Classifications

    • H—ELECTRICITY
    • H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
    • H02K—DYNAMO-ELECTRIC MACHINES
    • H02K1/00—Details of the magnetic circuit
    • H02K1/06—Details of the magnetic circuit characterised by the shape, form or construction
    • H02K1/22—Rotating parts of the magnetic circuit
    • H02K1/27—Rotor cores with permanent magnets
    • H—ELECTRICITY
    • H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
    • H02K—DYNAMO-ELECTRIC MACHINES
    • H02K1/00—Details of the magnetic circuit
    • H02K1/06—Details of the magnetic circuit characterised by the shape, form or construction
    • H02K1/22—Rotating parts of the magnetic circuit
    • H02K1/27—Rotor cores with permanent magnets
    • H02K1/2706—Inner rotors
    • H02K1/272—Inner rotors the magnetisation axis of the magnets being perpendicular to the rotor axis
    • H02K1/2726—Inner rotors the magnetisation axis of the magnets being perpendicular to the rotor axis the rotor consisting of a single magnet or two or more axially juxtaposed single magnets
    • H—ELECTRICITY
    • H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
    • H02K—DYNAMO-ELECTRIC MACHINES
    • H02K15/00—Methods or apparatus specially adapted for manufacturing, assembling, maintaining or repairing of dynamo-electric machines
    • H02K15/02—Methods or apparatus specially adapted for manufacturing, assembling, maintaining or repairing of dynamo-electric machines of stator or rotor bodies
    • H02K15/03—Methods or apparatus specially adapted for manufacturing, assembling, maintaining or repairing of dynamo-electric machines of stator or rotor bodies having permanent magnets
    • H—ELECTRICITY
    • H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
    • H02K—DYNAMO-ELECTRIC MACHINES
    • H02K21/00—Synchronous motors having permanent magnets; Synchronous generators having permanent magnets
    • H02K21/12—Synchronous motors having permanent magnets; Synchronous generators having permanent magnets with stationary armatures and rotating magnets
    • H02K21/14—Synchronous motors having permanent magnets; Synchronous generators having permanent magnets with stationary armatures and rotating magnets with magnets rotating within the armatures

Definitions

  • the present invention relates to an electric motor with permanent magnetic excitation, which has a rotor, on whose surface facing the inside of a stator, a plurality of permanent magnets are arranged.
  • Such a permanently magnetically excited electric motor is known, for example, from US Pat. No. 6,204,587 or DE 3 844 074 C2.
  • the rotors of the electric motors described in these publications have permanent magnets on their surface, with adjacent permanent magnets having opposite poles.
  • measures have to be taken in particular in high-speed engines to absorb the centrifugal forces acting on the permanent magnets.
  • a solid hollow cylinder is pushed onto the rotor in such a way that its inner wall rests directly on the permanent magnet.
  • the position of the permanent magnets is fixed on the rotor, thus reliably securing the permanent magnets even at very high speeds.
  • Permanent magnets which have a large wall thickness, are usually pressed from a magnetic material. Pressed magnetic material has only a low mechanical tensile strength, so that a z. B. from DE 3 844 074 C2 bandaging of the permanent magnets is required.
  • the invention has for its object to provide an electric motor of the type mentioned, in which the magnetic material forming the permanent magnets can be applied directly to the surface of the rotor in a relatively thin layer.
  • the rotor on the surface of which the material for the permanent magnets is applied, is provided on its surface and / or in its interior with cutouts which are placed and dimensioned in this way, that they do not interrupt lines of the magnetic flux which are aligned radially with respect to the surface of the rotor and which form a return line via the rotor.
  • the thermal expansion coefficients of the iron of the rotor and of the magnetic material differ very much, and the large heat capacity of the rotor leads to a rapid cooling of the z. B. applied by spraying magnetic material. Because of this, there is a risk that the applied magnetic material will tear. This undesirable effect can be reduced by the measure according to the invention for reducing the heat capacity avoid the rotor by making recesses in the rotor. Since the excitation flux, which runs from the permanent magnets of the rotor in the radial direction to the air gap between the rotor and the stator, increases the available torque of the motor, the recesses are placed in such a way that they just line the magnetic flux in the radial direction Do not interrupt the surface of the rotor.
  • the recesses are advantageously placed and dimensioned such that they are tangential or almost tangential to the rotor Interrupt lines of magnetic flux aligned with the surface of the rotor.
  • the permanent magnets advantageously consist of a layer of a plastic-bonded magnetic material sprayed onto the surface of the rotor.
  • At least one recess can be provided below each transition between two adjacent oppositely polarized permanent magnets, which has the shape of a slot that extends transversely to the longitudinal axis of the rotor. which extends in the direction of the longitudinal axis of the rotor.
  • Recesses in the interior of the rotor lead to a very strong reduction in the heat capacity of the rotor and they form ideal barriers for components of the magnetic flux oriented tangentially to the surface of the rotor.
  • the recesses located inside the rotor can be used to introduce a material into it that compensates for an imbalance in the rotor.
  • the rotor is advantageously constructed from layered iron sheets.
  • the only figure in the drawing shows a cross section through an electric motor, the stator 1 of which is shown only in part with two poles 2, 3 and the associated windings 4, 5.
  • a rotor 7 arranged on a motor shaft 6 is rotatably mounted within the stator 1.
  • the rotor 7 preferably consists of a stack of laminated iron sheets.
  • the stator 1 can consist of laminated iron sheets.
  • the rotor 7 and the stator 1 are preferably punched out of a sheet metal stack in one operation.
  • the electric motor shown in sections is a permanent magnet excited three-phase synchronous motor or a brushless DC motor. Therefore, the rotor 7 is coated on its surface with permanent magnets 8, 9, 10 and 11.
  • 4 permanent magnets 8, 9, 10 and 11 are applied to the surface of the rotor 7 in order to implement 4 magnetic poles, with adjacent permanent magnets being magnetized in the opposite direction radially to the surface of the rotor 7, as indicated by arrows.
  • the 4 permanent magnets 8, 9, 10, 11 are formed by a layer of a preferably plastic-bonded magnetic material (e.g. NdFeB) sprayed directly onto the surface of the rotor 7 forming an air gap with the inside of the stator 1.
  • the rotor 7 made of iron forms the yoke for the magnetic flux of the permanent magnets 8, 9, 10, 11.
  • the coefficients of thermal expansion of the magnetic material and the iron material of the rotor 7 are very different.
  • the heat capacity of the rotor 7 when it is made of a solid material is very high.
  • the heat capacity of the rotor yoke is very greatly reduced by the fact that recesses 12, 13, 14, 15 and / or recesses 16, 17, 18, 19 are made in the surface of the rotor 7 and 7.
  • cutouts 12 to 19 bring about a strong reduction in the thermal capacity of the rotor material, which prevents the magnetic material sprayed onto the rotor 7 from cooling down too quickly and thereby tearing.
  • the recesses 12, 13, 14 and 15, which are omitted in the surface of the rotor 7 and extend in the direction of the longitudinal axis, perpendicular to the plane of the drawing, of the rotor 7 are placed below the transitions between adjacent oppositely polarized permanent magnets 8, 9, 10, 11 ,
  • the placement of the recesses is chosen so that they are tangential or almost tangential to the surface lines of the magnetic flux which are aligned with the rotor and which form a return line via the rotor are interrupted.
  • several slot-shaped cutouts can also be embedded in the rotor 7.
  • the spin resistance of the rotor 7 can be increased by the fact that the recesses 12, 13, 14 and 15 embedded in the surface of the rotor 7 have a dovetail-shaped cross section. Because the dovetail shape of the recesses 12, 13, 14 and 15 enables the permanent magnets 8, 9, 10 and 11 to be wedged, so that they are secured not only against a rotational movement but also against a radial movement.
  • Non-magnetic material (“balancing cement”) can be introduced into the recesses 16, 17, 18, 19, which are in particular recessed in the interior of the rotor 7, in order to compensate for an imbalance of the rotor 7.

Landscapes

  • Engineering & Computer Science (AREA)
  • Power Engineering (AREA)
  • Manufacturing & Machinery (AREA)
  • Permanent Field Magnets Of Synchronous Machinery (AREA)
  • Iron Core Of Rotating Electric Machines (AREA)
  • Permanent Magnet Type Synchronous Machine (AREA)

Abstract

According to the invention, the rotor (7) of an electric motor is provided with recesses (12, 13, 14, 15, 16, 17, 18, 19) on its surface and/or in its inner region, said recesses being positioned and measured in such a way that they do not interrupt lines of the magnetic current which are radially oriented in relation to the surface of the rotor (7) and which form a return path by means of the rotor (7). Said recesses reduce the thermal capacity of the rotor (7) to such an extent that a layer forming a plurality of permanent magnets (8, 9, 10, 11), and consisting of a magnetic material, can be sprayed onto the surface of the rotor (7).

Description

Permanentmagnetisch erregter ElektromotorElectric motor with permanent magnet excitation
Stand der TechnikState of the art
Die vorliegende Erfindung betrifft einen Elektromotor mit permanentmagnetischer Erregung, der einen Rotor besitzt, auf dessen der Innenseite eines Stators zugewandten Oberflache mehrere Permanentmagnete angeordnet sind.The present invention relates to an electric motor with permanent magnetic excitation, which has a rotor, on whose surface facing the inside of a stator, a plurality of permanent magnets are arranged.
Ein derartiger permanentmagnetisch erregter Elektromotor ist beispielsweise aus der US 6,204,587 oder der DE 3 844 074 C2 bekannt. Die Rotoren der in diesen Veröffentlichungen beschriebenen Elektromotoren tragen auf ihrer Oberflache Permanentmagnete, wobei jeweils benachbarte Permanentmagnete entgegengesetzt gepolt sind. Wie insbesondere aus der DE 3 844 074 C2 hervorgeht, müssen gerade bei hochtourigen Motoren Maßnahmen ergriffen werden, um die auf die Permanentmagnete wirkenden Fliehkräfte aufzunehmen. Dazu wird auf den Rotor ein massiver Hohlzylinder aufgeschoben, und zwar derart, dass er mit seiner Innenwand unmittelbar auf den Permanentmagneten aufliegt. Dadurch werden die Permanentmagnete in ihrer Lage auf dem Rotor fixiert und damit eine auch bei sehr hohen Drehzahlen zuverlässige Befestigung der Permanentmagnete erreicht. Derartige relativ aufwendige Maßnahmen zur Fixierung der Permanentmagnete sind erst recht dann erforderlich, wenn die Permanentmagnete eine große Wandstarke aufweisen, damit sie nicht radial sondern lateral magnetisiert werden können, um auf einen magnetischen Ruckschluß durch den Rotor verzichten zu können. Permanentmagnete, die von großer Wandstarke sind, werden üblicherweise aus einem Magnetmaterial gepreßt. Gepreßtes Magnetmaterial weist aber nur eine geringe mechanische Zugfestigkeit auf, so dass eine z. B. aus der DE 3 844 074 C2 hervorgehende Bandagierung der Permanentmagnete erforderlich ist.Such a permanently magnetically excited electric motor is known, for example, from US Pat. No. 6,204,587 or DE 3 844 074 C2. The rotors of the electric motors described in these publications have permanent magnets on their surface, with adjacent permanent magnets having opposite poles. As can be seen in particular from DE 3 844 074 C2, measures have to be taken in particular in high-speed engines to absorb the centrifugal forces acting on the permanent magnets. For this purpose, a solid hollow cylinder is pushed onto the rotor in such a way that its inner wall rests directly on the permanent magnet. As a result, the position of the permanent magnets is fixed on the rotor, thus reliably securing the permanent magnets even at very high speeds. Such relatively complex measures for fixing the permanent magnets are only necessary if the permanent magnets are one have large wall thicknesses so that they cannot be magnetized radially but laterally in order to be able to dispense with a magnetic yoke through the rotor. Permanent magnets, which have a large wall thickness, are usually pressed from a magnetic material. Pressed magnetic material has only a low mechanical tensile strength, so that a z. B. from DE 3 844 074 C2 bandaging of the permanent magnets is required.
Der Erfindung liegt die Aufgabe zugrunde, einen Elektromotor der eingangs genannten Art anzugeben, bei dem das die Permanentmagnete bildende Magnetmaterial in einer relativ dünnen Schicht direkt auf die Oberflache des Rotors aufgebracht werden kann.The invention has for its object to provide an electric motor of the type mentioned, in which the magnetic material forming the permanent magnets can be applied directly to the surface of the rotor in a relatively thin layer.
Vorteil der Erfindung:Advantage of the invention:
Die genannte Aufgabe wird mit den Merkmalen des Anspruchs 1 dadurch gelost, dass der Rotor, auf dessen Oberflache das Material für die Permanentmagnete aufgebracht wird, auf seiner Oberflache und/oder in seinem Inneren mit Aussparungen versehen ist, die so platziert und so bemessen sind, dass sie radial zur Oberflache des Rotors ausgerichtete und über den Rotor einen Ruckschluß bildende Linien des magnetischen Flußes nicht unterbrechen.The stated object is achieved with the features of claim 1 in that the rotor, on the surface of which the material for the permanent magnets is applied, is provided on its surface and / or in its interior with cutouts which are placed and dimensioned in this way, that they do not interrupt lines of the magnetic flux which are aligned radially with respect to the surface of the rotor and which form a return line via the rotor.
Die thermischen Ausdehnungskoeffizienten vom Eisen des Rotors und von dem Magnetmaterial differieren nämlich sehr stark, und die große Wärmekapazität des Rotors fuhrt zu einer schnellen Auskuhlung des auf den Rotor z. B. durch Spritzen aufgebrachten Magnetmaterials. Aufgrund dessen besteht die Gefahr, dass das aufgebrachte Magnetmaterial reißt. Dieser unerwünschte Effekt laßt sich durch die erfmdungsgemaße Maßnahme zur Reduzierung der Wärmekapazität des Rotors durch Einbringen von Aussparungen in den Rotor vermeiden. Da grade der Erregerfluß, der von den Permanentmagneten des Rotors aus in radialer Richtung zum Luftspalt zwischen dem Rotor und dem Stator verlauft, das verfugbare Drehmoment des Motors erhöht, sind die Aussparungen so platziert, dass sie gerade die Linien des magnetischen Flußes in radialer Richtung zur Oberflache des Rotors nicht unterbrechen.The thermal expansion coefficients of the iron of the rotor and of the magnetic material differ very much, and the large heat capacity of the rotor leads to a rapid cooling of the z. B. applied by spraying magnetic material. Because of this, there is a risk that the applied magnetic material will tear. This undesirable effect can be reduced by the measure according to the invention for reducing the heat capacity avoid the rotor by making recesses in the rotor. Since the excitation flux, which runs from the permanent magnets of the rotor in the radial direction to the air gap between the rotor and the stator, increases the available torque of the motor, the recesses are placed in such a way that they just line the magnetic flux in the radial direction Do not interrupt the surface of the rotor.
Vorteilhafte Weiterbildungen der Erfindung gehen aus den Unteranspruchen hervor.Advantageous developments of the invention emerge from the subclaims.
Da die tangential bzw. nahezu tangential zur Oberflache des Rotors ausgerichteten und über den Rotor einen Ruckschluß bildenden Linien des magnetischen Flußes das verfugbare Drehmoment des Rotors verringern, werden die Aussparungen vorteilhafter Weise so platziert und so bemessen, dass sie diese tangential bzw. nahezu tangential zur Oberflache des Rotors ausgerichteten Linien des magnetischen Flußes unterbrechen.Since the lines of the magnetic flux which are oriented tangentially or almost tangentially to the surface of the rotor and which form a return line via the rotor reduce the available torque of the rotor, the recesses are advantageously placed and dimensioned such that they are tangential or almost tangential to the rotor Interrupt lines of magnetic flux aligned with the surface of the rotor.
Die Permanentmagnete bestehen vorteilhafter Weise aus einer auf die Oberflache des Rotors aufgespritzten Schicht aus einem kunststoffgebundenen Magnetmaterial.The permanent magnets advantageously consist of a layer of a plastic-bonded magnetic material sprayed onto the surface of the rotor.
Es ist zweckmäßig, in der Oberflache des Rotors in Bereichen zwischen jeweils zwei entgegengesetzt gepolten Permanentmagneten Aussparungen einzulassen, die sich in Richtung der Langsachse des Rotors erstrecken. Die Schleuderfestigkeit des Rotors kann dadurch erhöht werden, dass diese Aussparungen einen schwalbenschwanzformigen Querschnitt aufweisen. Denn die Schwalbenschwanzform der Aussparungen ermöglicht eine Verkeilung der Permanentmagnete, so dass sie nicht nur gegen eine Rototionsbewegung sondern auch gegen eine radiale Bewegung gesichert sind. Es kann zusatzlich zu den in der Oberflache des Rotors eingelassenen Aussparungen oder auch ausschließlich im Innern des Rotors jeweils unterhalb eines jeden Übergangs zwischen zwei benachbarten entgegengesetzt gepolten Permanentmagneten mindestens eine Aussparung vorgesehen werden, welche die Form eines sich quer zur Langsachse des Rotors ausdehnenden Schlitzes hat, der sich in Richtung der Langsachse des Rotors erstreckt. Aussparungen im Innern des Rotors fuhren einerseits zu einer sehr starken Reduzierung der Wärmekapazität des Rotors und sie bilden ideale Sperren für tangential zur Oberflache des Rotors ausgerichtete Komponenten des magnetischen Flußes.It is expedient to allow recesses in the surface of the rotor in areas between two oppositely polarized permanent magnets which extend in the direction of the longitudinal axis of the rotor. The centrifugal strength of the rotor can be increased in that these recesses have a dovetail-shaped cross section. Because the dovetail shape of the recesses allows the permanent magnets to wedge, so that they are not only secured against a rotational movement but also against a radial movement. In addition to the recesses in the surface of the rotor or also exclusively in the interior of the rotor, at least one recess can be provided below each transition between two adjacent oppositely polarized permanent magnets, which has the shape of a slot that extends transversely to the longitudinal axis of the rotor. which extends in the direction of the longitudinal axis of the rotor. Recesses in the interior of the rotor on the one hand lead to a very strong reduction in the heat capacity of the rotor and they form ideal barriers for components of the magnetic flux oriented tangentially to the surface of the rotor.
Die im Innern des Rotors befindlichen Aussparungen können dazu ausgenutzt werden, um ein Material darin einzubringen, das eine Unwucht des Rotors ausgleicht.The recesses located inside the rotor can be used to introduce a material into it that compensates for an imbalance in the rotor.
Der Rotor ist vorteilhafter Weise aus geschichteten Eisenblechen aufgebaut.The rotor is advantageously constructed from layered iron sheets.
Beschreibung eines Ausfuhrungsbeispiels:Description of an exemplary embodiment:
Die einzige Figur der Zeichnung zeigt einen Querschnitt durch einen Elektromotor, dessen Stator 1 nur ausschnittweise mit zwei Polen 2, 3 und den dazugehörigen Wicklungen 4, 5 dargestellt ist. Innerhalb des Stators 1 ist ein auf einer Motorwelle 6 angeordneter Rotor 7 drehbar gelagert. Der Rotor 7 besteht vorzugsweise aus einem Stapel von aufeinander geschichteten Eisenblechen. Ebenso kann der Stator 1 aus aufeinander geschichteten Eisenblechen bestehen. Der Rotor 7 und der Stator 1 werden vorzugsweise in einem Arbeitsvorgang aus einem Blechstapel herausgestanzt . Der ausschnittweise dargestellte Elektromotor ist ein permanentmagnetisch erregter Drehstromsynchronmotor bzw. ein burstenloser Gleichstrommotor. Deshalb ist der Rotor 7 an seiner Oberflache mit Permanentmagneten 8, 9, 10 und 11 beschichtet. Bei dem dargestellten Ausfuhrungsbeispiel sind zur Realisierung von 4 Magnetpolen 4 Permanentmagnete 8, 9, 10 und 11 auf der Oberflache des Rotors 7 aufgebracht, wobei jeweils einander benachbarte Permanentmagnete, wie durch Pfeile angedeutet, in entgegengesetzte Richtung radial zur Oberflache des Rotors 7 magnetisiert sind. Die 4 Permanentmagnete 8, 9, 10, 11 werden durch eine direkt auf die mit der Innenseite des Stators 1 einen Luftspalt bildende Oberflache des Rotors 7 aufgespritzte Schicht aus einem vorzugsweise kunstoffgebundenen Magnetmaterial (z. B. NdFeB) gebildet. Der aus Eisen bestehende Rotor 7 bildet das Ruckschlußjoch für den magnetischen Fluß der Permanentmagnete 8, 9, 10, 11.The only figure in the drawing shows a cross section through an electric motor, the stator 1 of which is shown only in part with two poles 2, 3 and the associated windings 4, 5. A rotor 7 arranged on a motor shaft 6 is rotatably mounted within the stator 1. The rotor 7 preferably consists of a stack of laminated iron sheets. Likewise, the stator 1 can consist of laminated iron sheets. The rotor 7 and the stator 1 are preferably punched out of a sheet metal stack in one operation. The electric motor shown in sections is a permanent magnet excited three-phase synchronous motor or a brushless DC motor. Therefore, the rotor 7 is coated on its surface with permanent magnets 8, 9, 10 and 11. In the exemplary embodiment shown, 4 permanent magnets 8, 9, 10 and 11 are applied to the surface of the rotor 7 in order to implement 4 magnetic poles, with adjacent permanent magnets being magnetized in the opposite direction radially to the surface of the rotor 7, as indicated by arrows. The 4 permanent magnets 8, 9, 10, 11 are formed by a layer of a preferably plastic-bonded magnetic material (e.g. NdFeB) sprayed directly onto the surface of the rotor 7 forming an air gap with the inside of the stator 1. The rotor 7 made of iron forms the yoke for the magnetic flux of the permanent magnets 8, 9, 10, 11.
Die thermischen Ausdehnungskoeffizienten des Magnetmaterials und des Eisenmaterials des Rotors 7 sind sehr unterschiedlich. Außerdem ist die Wärmekapazität des Rotors 7 wenn dieser aus einem Vollmaterial besteht, sehr hoch. Für das auf den Rotor 7 aufgespritzte Magnetmaterial besteht daher wegen eines zu schnellen Auskuhlens aufgrund der hohen Wärmekapazität des darunter befindlichen Rotors 7 die Gefahr, dass die aufgespritzte Magnetschicht reißt. Um das zu verhindern, wird die Wärmekapazität des Rotorjochs sehr stark dadurch reduziert, das an der Oberflache des Rotor 7 Aussparungen 12, 13, 14, 15 und/oder im Innern des Rotors 7 Aussparungen 16, 17, 18, 19 eingelassen werden. Diese Aussparungen 12 bis 19 bewirken eine starke Reduzierung der Wärmekapazität des Rotormaterials, wodurch verhindert wird, dass das auf den Rotor 7 aufgespritzte Magnetmaterial zu schnell auskühlt und dadurch reißt. Die in der Oberflache des Rotors 7 ausgelassenen Aussparungen 12, 13, 14 und 15, die sich in Richtung der Langsachse, senkrecht zur Zeichenebene, des Rotors 7 erstrecken, sind unterhalb der Übergänge zwischen benachbarten entgegengesetzt gepolten Permanentmagneten 8, 9, 10, 11 platziert. Wie aus "Berichte aus dem Institut für elektrische Maschinen und Antriebe", Band 7, Volker Bosch: Elektronisch kommutiertes Einzelspindelantriebssystem, Shaker Verlag, Aachen 2001, hervorgeht, ist diese Platzierung der Aussparungen deshalb gewählt, damit durch sie tangential bzw. nahezu tangential zur Oberflache des Rotors ausgerichtete und über den Rotor einen Ruckschluß bildende Linien des magnetischen Flußes unterbrochen werden. Dadurch wird erreicht, dass tangential im Luftspalt zwischen dem Rotor 7 und dem Stator 1 ausgerichtete Flußlinien, welche das Drehmoment des Motors schwachen, gesperrt werden. Dagegen sollen die radial zur Oberflache des Rotors 7 ausgerichteten magnetischen Flußlinien nicht gesperrt werden, weil sie das verfugbare Drehmoment des Motors erhohen. Nach diesen Gesichtspunkten sind auch die im Innern des Rotor 7 eingelassenen, ebenfalls in Langsachsrichtung des Rotors 7 sich erstreckenden Aussparungen 16, 17, 18, 19 unterhalb der Übergänge zwischen benachbarten entgegengesetzt gepolten Permanentmagneten 8, 9, 10, 11 platziert und bemessen.The coefficients of thermal expansion of the magnetic material and the iron material of the rotor 7 are very different. In addition, the heat capacity of the rotor 7 when it is made of a solid material is very high. For the magnetic material sprayed onto the rotor 7, there is therefore a risk that the sprayed-on magnetic layer will tear due to the rapid cooling down due to the high thermal capacity of the rotor 7 located underneath. In order to prevent this, the heat capacity of the rotor yoke is very greatly reduced by the fact that recesses 12, 13, 14, 15 and / or recesses 16, 17, 18, 19 are made in the surface of the rotor 7 and 7. These cutouts 12 to 19 bring about a strong reduction in the thermal capacity of the rotor material, which prevents the magnetic material sprayed onto the rotor 7 from cooling down too quickly and thereby tearing. The recesses 12, 13, 14 and 15, which are omitted in the surface of the rotor 7 and extend in the direction of the longitudinal axis, perpendicular to the plane of the drawing, of the rotor 7 are placed below the transitions between adjacent oppositely polarized permanent magnets 8, 9, 10, 11 , As can be seen from "Reports from the Institute for Electrical Machines and Drives", Volume 7, Volker Bosch: Electronically commutated single spindle drive system, Shaker Verlag, Aachen 2001, the placement of the recesses is chosen so that they are tangential or almost tangential to the surface lines of the magnetic flux which are aligned with the rotor and which form a return line via the rotor are interrupted. It is thereby achieved that flux lines aligned tangentially in the air gap between the rotor 7 and the stator 1, which weaken the torque of the motor, are blocked. In contrast, the magnetic flux lines aligned radially to the surface of the rotor 7 should not be blocked because they increase the available torque of the motor. According to these points of view, the recesses 16, 17, 18, 19 which are embedded in the interior of the rotor 7 and also extend in the longitudinal axis direction of the rotor 7 are placed and dimensioned below the transitions between adjacent oppositely polarized permanent magnets 8, 9, 10, 11.
Eine optimale Sperre für tangential bzw. nahezu tangential zur Rotoroberflache verlaufende magnetische Flußlinien bilden Aussparungen 16, 17, 18, 19, die einen quer zur Rotor-Langsachse verlaufenden schlitzförmigen Querschnitt haben. Statt, wie in der Figur dargestellt, unter jedem Übergang zwischen zwei benachbarten Permanentmagneten nur eine Aussparung 16, 17, 18, 19 vorzusehen, können auch mehrere zum Beispiel in radialer Richtung gestaffelte schlitzförmige Aussparungen in den Rotor 7 eingelassen sein. Die Schleuderfestigkeit des Rotor 7 laßt sich dadurch vergrößern, das die in die Oberflache des Rotor 7 eingelassenen Aussparungen 12, 13, 14 und 15 einen schwalbenschwanzformigen Querschnitt aufweisen. Denn die Schwalbenschwanzform der Aussparungen 12, 13, 14 und 15 ermöglicht eine Verkeilung der Permanentmagnete 8, 9, 10 und 11, so dass sie nicht nur gegen eine Rototionsbewegung sondern auch gegen eine radiale Bewegung gesichert sind.Recesses 16, 17, 18, 19, which have a slot-shaped cross section running transversely to the longitudinal axis of the rotor, form an optimal barrier for magnetic flux lines running tangentially or almost tangentially to the rotor surface. Instead of providing only one cutout 16, 17, 18, 19 under each transition between two adjacent permanent magnets, as shown in the figure, several slot-shaped cutouts, for example staggered in the radial direction, can also be embedded in the rotor 7. The spin resistance of the rotor 7 can be increased by the fact that the recesses 12, 13, 14 and 15 embedded in the surface of the rotor 7 have a dovetail-shaped cross section. Because the dovetail shape of the recesses 12, 13, 14 and 15 enables the permanent magnets 8, 9, 10 and 11 to be wedged, so that they are secured not only against a rotational movement but also against a radial movement.
In die insbesondere im Inneren des Rotors 7 eingelassenen Aussparungen 16, 17, 18, 19 kann nichtmagnetisches Material („Wuchtkitt") eingebracht werden, um eine Unwucht des Rotors 7 auszugleichen. Non-magnetic material (“balancing cement”) can be introduced into the recesses 16, 17, 18, 19, which are in particular recessed in the interior of the rotor 7, in order to compensate for an imbalance of the rotor 7.

Claims

Ansprüche Expectations
1. Elektromotor mit permanentmagnetischer Erregung, der einen Rotor (7) besitzt, auf dessen der Innenseite eines Stators (1) zugewandten Oberflache mehrere Permanentmagnete (8, 9, 10, 11) angeordnet sind, dadurch gekennzeichnet, dass der Rotor (7) an seiner Oberflache und/oder in seinem Inneren mit Aussparungen (12, 13, 14, 15, 16, 17, 18, 19) versehen ist, die so platziert und so bemessen sind, dass sie radial zur Oberflache des Rotors (7) ausgerichtete und über den Rotor (7) einen Ruckschluß bildende Linie des magnetischen Flußes nicht unterbrechen.1. Electric motor with permanent magnetic excitation, which has a rotor (7), on the inside of which a stator (1) facing surface a plurality of permanent magnets (8, 9, 10, 11) are arranged, characterized in that the rotor (7) its surface and / or in its interior is provided with cutouts (12, 13, 14, 15, 16, 17, 18, 19) which are placed and dimensioned such that they are aligned radially to the surface of the rotor (7) and Do not interrupt the magnetic flux line forming a return line via the rotor (7).
2. Elektromotor nach Anspruch 1, dadurch gekennzeichnet, dass die Aussparungen (12, 13, 14, 15, 16, 17, 18, 19) so platziert und so bemessen sind, dass sie tangential bzw. nahezu tangential zur Oberflache des Rotors (7) ausgerichtete und über den Rotor (7) einen Ruckschluß bildende Linie des magnetischen Flußes unterbrechen.2. Electric motor according to claim 1, characterized in that the recesses (12, 13, 14, 15, 16, 17, 18, 19) are placed and dimensioned such that they are tangential or almost tangential to the surface of the rotor (7 ) aligned and interrupt via the rotor (7) forming a line of magnetic flux.
3. Elektromotor nach Anspruch 1, dadurch gekennzeichnet, dass die Permanentmagnete (8, 9, 10, 11) aus einer auf die Oberflache des Rotors (7) aufgespritzten Schicht aus einem kunststoffgebundenen Magnetmaterial bestehen. 3. Electric motor according to claim 1, characterized in that the permanent magnets (8, 9, 10, 11) consist of a layer of a plastic-bonded magnetic material sprayed onto the surface of the rotor (7).
4. Elektromotor nach Anspruch 1 oder 2, dadurch gekennzeichnet, dass in der Oberflache des Rotors (7) im Bereich zwischen jeweils zwei entgegengesetzt gepolten Permanentmagneten (8, 9, 10, 11) Aussparungen (12, 13, 14, 15) eingelassen sind, die sich in Richtung der Langsachse des Rotors (7) erstrecken.4. Electric motor according to claim 1 or 2, characterized in that in the surface of the rotor (7) in the area between two oppositely polarized permanent magnets (8, 9, 10, 11) recesses (12, 13, 14, 15) are embedded which extend in the direction of the longitudinal axis of the rotor (7).
5. Elektromotor nach Anspruch 4, dadurch gekennzeichnet, dass die Aussparungen (12, 13, 14, 15) einen schwalbenschwanzfόrmigen Querschnitt aufweisen.5. Electric motor according to claim 4, characterized in that the recesses (12, 13, 14, 15) have a dovetail cross-section.
6. Elektromotor nach einem der Ansprüche 1 oder 2, dadurch gekennzeichnet, das im Inneren des Rotors (7) jeweils unterhalb eines jeden Übergangs zwischen zwei benachbarten entgegengesetzt gepolten Permanentmagneten (8, 9, 10, 11) mindestens eine Aussparung (16, 17, 18, 19) vorhanden ist, welche die Form eines sich quer zur Langsachse des Rotors (7) ausdehnenden Schlitzes hat, der sich in Richtung der Langsachse des Rotors (7) erstreckt.6. Electric motor according to one of claims 1 or 2, characterized in that in the interior of the rotor (7) in each case below each transition between two adjacent oppositely polarized permanent magnets (8, 9, 10, 11) at least one recess (16, 17, 18, 19) is present which has the shape of a slot which extends transversely to the longitudinal axis of the rotor (7) and extends in the direction of the longitudinal axis of the rotor (7).
7. Elektromotor nach einem der Ansprüche 1 oder 6, dadurch gekennzeichnet, dass in ein oder mehrere der sich im Inneren des Rotors (7) befindenden Aussparungen (16, 17, 18, 19) ein Material eingebracht ist, das eine Unwucht des Rotors (7) ausgleicht.7. Electric motor according to one of claims 1 or 6, characterized in that a material is introduced into one or more of the recesses (16, 17, 18, 19) located in the interior of the rotor (7), which imbalance of the rotor ( 7) compensates.
8. Elektromotor nach einem der vorhergehenden Ansprüche, dadurch gekennzeichnet, dass der Rotor (7) aus geschichteten Eisenblechen besteht. 8. Electric motor according to one of the preceding claims, characterized in that the rotor (7) consists of layered iron sheets.
EP02717982A 2001-07-18 2002-02-27 Electric motor excited by permanent magnets Withdrawn EP1421664A1 (en)

Applications Claiming Priority (3)

Application Number Priority Date Filing Date Title
DE10135019A DE10135019A1 (en) 2001-07-18 2001-07-18 Electric motor with permanent magnet excitation
DE10135019 2001-07-18
PCT/DE2002/000725 WO2003009449A1 (en) 2001-07-18 2002-02-27 Electric motor excited by permanent magnets

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EP1421664A1 true EP1421664A1 (en) 2004-05-26

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US (1) US6803690B2 (en)
EP (1) EP1421664A1 (en)
JP (1) JP2004521600A (en)
KR (1) KR100913683B1 (en)
CN (1) CN1286244C (en)
DE (1) DE10135019A1 (en)
WO (1) WO2003009449A1 (en)

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KR100913683B1 (en) 2009-08-24
JP2004521600A (en) 2004-07-15
US6803690B2 (en) 2004-10-12
CN1462499A (en) 2003-12-17
US20030151324A1 (en) 2003-08-14
WO2003009449A1 (en) 2003-01-30
CN1286244C (en) 2006-11-22
KR20040019333A (en) 2004-03-05
DE10135019A1 (en) 2003-01-30

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