WO1997008716A1 - Method of producing magnetic poles on a base member, and rotor of an electrical machine - Google Patents

Method of producing magnetic poles on a base member, and rotor of an electrical machine Download PDF

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Publication number
WO1997008716A1
WO1997008716A1 PCT/DK1996/000358 DK9600358W WO9708716A1 WO 1997008716 A1 WO1997008716 A1 WO 1997008716A1 DK 9600358 W DK9600358 W DK 9600358W WO 9708716 A1 WO9708716 A1 WO 9708716A1
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WO
WIPO (PCT)
Prior art keywords
rotor
base member
permanent magnet
magnet material
spraying
Prior art date
Application number
PCT/DK1996/000358
Other languages
French (fr)
Inventor
Per Kjeldsteen
Aksel Baagø JEPSEN
Original Assignee
Danfoss A/S
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
Priority to AU67331/96A priority Critical patent/AU6733196A/en
Application filed by Danfoss A/S filed Critical Danfoss A/S
Publication of WO1997008716A1 publication Critical patent/WO1997008716A1/en

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Classifications

    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01F—MAGNETS; INDUCTANCES; TRANSFORMERS; SELECTION OF MATERIALS FOR THEIR MAGNETIC PROPERTIES
    • H01F41/00—Apparatus or processes specially adapted for manufacturing or assembling magnets, inductances or transformers; Apparatus or processes specially adapted for manufacturing materials characterised by their magnetic properties
    • H01F41/02—Apparatus or processes specially adapted for manufacturing or assembling magnets, inductances or transformers; Apparatus or processes specially adapted for manufacturing materials characterised by their magnetic properties for manufacturing cores, coils, or magnets
    • H01F41/0253—Apparatus or processes specially adapted for manufacturing or assembling magnets, inductances or transformers; Apparatus or processes specially adapted for manufacturing materials characterised by their magnetic properties for manufacturing cores, coils, or magnets for manufacturing permanent magnets
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01F—MAGNETS; INDUCTANCES; TRANSFORMERS; SELECTION OF MATERIALS FOR THEIR MAGNETIC PROPERTIES
    • H01F1/00—Magnets or magnetic bodies characterised by the magnetic materials therefor; Selection of materials for their magnetic properties
    • H01F1/01—Magnets or magnetic bodies characterised by the magnetic materials therefor; Selection of materials for their magnetic properties of inorganic materials
    • H01F1/03—Magnets or magnetic bodies characterised by the magnetic materials therefor; Selection of materials for their magnetic properties of inorganic materials characterised by their coercivity
    • H01F1/032—Magnets or magnetic bodies characterised by the magnetic materials therefor; Selection of materials for their magnetic properties of inorganic materials characterised by their coercivity of hard-magnetic materials
    • H01F1/04—Magnets or magnetic bodies characterised by the magnetic materials therefor; Selection of materials for their magnetic properties of inorganic materials characterised by their coercivity of hard-magnetic materials metals or alloys
    • H01F1/047—Alloys characterised by their composition
    • H01F1/053—Alloys characterised by their composition containing rare earth metals
    • H01F1/055—Alloys characterised by their composition containing rare earth metals and magnetic transition metals, e.g. SmCo5
    • H01F1/057—Alloys characterised by their composition containing rare earth metals and magnetic transition metals, e.g. SmCo5 and IIIa elements, e.g. Nd2Fe14B
    • H01F1/0571—Alloys characterised by their composition containing rare earth metals and magnetic transition metals, e.g. SmCo5 and IIIa elements, e.g. Nd2Fe14B in the form of particles, e.g. rapid quenched powders or ribbon flakes
    • H01F1/0574—Alloys characterised by their composition containing rare earth metals and magnetic transition metals, e.g. SmCo5 and IIIa elements, e.g. Nd2Fe14B in the form of particles, e.g. rapid quenched powders or ribbon flakes obtained by liquid dynamic compaction
    • 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

Definitions

  • the invention relates to a method of producing magnetic poles on a base member, and furthermore to a rotor of an electrical machine which has poles that are formed by permanent magnets.
  • the magnetic poles on the rotor are in some cases formed by permanent magnets. Such constructions are well known both for synchronous machines and for d.e. machines.
  • the magnets are then in the form, for example, of arcuate shaped members which are mounted on the rotor. Fixing is effected by means of adhesive or other mechanical connections.
  • Permanent magnets, encapsulated as bars in the rotor, are an alternative thereto. These are then referred to as embedded (buried) magnets. Magnetization of the permanent magnets can be effected before or after mounting. At any rate, a series of operations are required to complete the rotor.
  • the permanent magnet material is preferably sprayed on in the form of a powder.
  • the individual powder grains are then on the one hand bonded to the surface of the base member and on the other hand also to each other. This produces a very stable bond of the powder on the surface of the base member. Moreover, such a powder is easy to handle, so that it is possible to build up a layer with relatively little effort.
  • the heat treatment is preferably effected in a non ⁇ oxidizing atmosphere. In this manner the sprayed-on layer is prevented from oxidizing during the heat treatment.
  • the surface of the base member is roughened prior to the spraying operation. This increases the strength of the bond between the sprayed- on permanent magnet material and the base member.
  • the surface of the base member is in any case rough, so that subsequent layers are likewise firmly held.
  • the surface of the base member, or more accurately, the surface of the permanent magnet material has a rough surface, which has "valleys" and "peaks". There is here probably a danger that during magnetization the "molecular magnets" become oriented in such a way that their actions virtually cancel each other out.
  • Fig. l shows a base member for a rotor
  • Fig. 2 shows the rotor, which is provided with a layer of permanent magnet material
  • Fig. 3 shows the rotor in plan view
  • Fig. 4 shows the rotor in longitudinal section
  • Fig. 5 shows an electron micrograph of NdFeB in a powder state
  • Fig. 6 shows an electron micrograph of NdFeB after it has been sprayed on.
  • Fig. 1 shows a rotor 1 of an electrical machine in its unfinished state. Either the rotor 1 is in the form of a solid body of soft iron or it consists of laminations stacked one on top of the other, between which insulators are provided in order to avoid the formation of eddy currents. The construction of the rotor 1 as a base member is not significant for the following description, however.
  • the rotor 1 has a central bore 2 which later serves to receive a rotor shaft.
  • the layer 4 can be provided with a further protective layer 5 in order to avoid oxidation.
  • the rotor is made as follows. NdFeB powder, which is shown on an enlarged scale by an electron micrograph in Fig. 5, is applied to the surface 3 of the rotor 1 by plasma spraying. Plasma spraying is known per se and belongs to the category of thermal spraying in which the powder can be applied at a high temperature to the surface 3 of the rotor 1. To carry out the plasma spraying, the NdFeB powder is heated in a plasma spraying apparatus to a plasma at a temperature in the typical range from 5,000° to 15,000°C, whereupon the surface of the powder material fuses. The powder is then sprayed onto the rotor 1 which rotates steadily during the spraying so that the layer is sprayed on uniformly. Fig. 2 shows the rotor 1 after spraying. The NdFeB layer 4 is shown hatched.
  • the typical thickness of the layer 4 after spraying is about 1 mm. Alternatively, it can vary in a range from a few ⁇ m to several mm.
  • the individual particles or grains of the powder are welded during spraying partly to the surface 3 of the rotor and partly to other particles.
  • This welding produces a very good cohesive strength of the powder in itself and of the powder with the surface 3 of the rotor.
  • the rotor 1 can also be exposed to relatively high speeds of rotation, the layer 4 being subjected to correspondingly large centrifugal forces.
  • plasma spraying of the NdFeB material there is a structural change.
  • the starting material is crystalline. After the spraying, however, an amorphous structure can be observed. In the starting powder the constituents Fe and Nd have an intermetallic bond with one another which in many cases disintegrates after the plasma spraying.
  • the surface of the layer 4 is relatively rough.
  • the magnetism produced is only weak. This is attributable to the fact that the "molecular magnets" are able to orientate themselves in such a way that their actions virtually cancel each other out.
  • the surface of the layer 4 is made smooth by grinding off a thin layer of the order of magnitude of about 0.1 mm, or by polishing.
  • the protective layer 5 can be applied after the smoothing operation.
  • the rotor is then ready for magnetization and can be provided with the desired number of poles.
  • magnetization of the rotor can be effected with a magnetic field strength of 3200 kA/m.
  • the magnetic field strength can be varied according to need.
  • the method is not restricted to the manufacture of rotors for electrical machines. It is possible also, of course, to produce armatures and stators of linear motors. Sensors having magnetic poles tailored to requirements can be made. Valves or other actuating elements with permanent magnets can also be manufactured in this manner.

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  • Engineering & Computer Science (AREA)
  • Power Engineering (AREA)
  • Manufacturing & Machinery (AREA)
  • Chemical & Material Sciences (AREA)
  • Crystallography & Structural Chemistry (AREA)
  • Inorganic Chemistry (AREA)
  • Permanent Field Magnets Of Synchronous Machinery (AREA)
  • Manufacture Of Motors, Generators (AREA)
  • Coating By Spraying Or Casting (AREA)

Abstract

A method of producing magnetic poles on a base member (1) is disclosed. It is desirable to be able to improve this method. To that end, the permanent magnet material is sprayed onto the base member (1) by a thermal process and is subsequently magnetized.

Description

Method of producing magnetic poles on a base member, and rotor of an electrical machine.
The invention relates to a method of producing magnetic poles on a base member, and furthermore to a rotor of an electrical machine which has poles that are formed by permanent magnets.
In the following description a rotor of an electrical machine shall serve as an example for explaining the invention. The method for producing magnetic poles may, however, also be applied in the case of other items, for example, in the case of armatures or stators of linear motors and in the case of other items and devices which require permanent magnets.
In electrical machines, the magnetic poles on the rotor are in some cases formed by permanent magnets. Such constructions are well known both for synchronous machines and for d.e. machines. The magnets are then in the form, for example, of arcuate shaped members which are mounted on the rotor. Fixing is effected by means of adhesive or other mechanical connections. Permanent magnets, encapsulated as bars in the rotor, are an alternative thereto. These are then referred to as embedded (buried) magnets. Magnetization of the permanent magnets can be effected before or after mounting. At any rate, a series of operations are required to complete the rotor.
More of a problem, however is the fact that the permanent magnets on the rotor are subjected to relatively high centrifugal forces, which consequently place great demands on the fixing between the rotor and permanent magnets. This fixing is moreover exposed to the effect of heat, which is inevitably produced during operation of the electrical machine. Many adhesives reduce or lose their retentive force at elevated temperatures. Up until now the permanent magnets have therefore been a weak point of electrical machines.
The invention is based on the problem of improving the production of magnetic poles on a base member.
That problem is solved in a method of the kind mentioned in the introduction in that a permanent magnet material is sprayed onto the base member by a thermal process and is subsequently magnetized.
Thermal spray-application produces on the base member a layer of the permanent magnet material, which is very firmly joined to the base member and additionally has inherently a very stable cohesive strength. A high mechanical strength is achieved as a result. The base member and the magnetic poles hold together in a very secure manner. The base member is therefore well able to withstand stress. Because the permanent magnet layer is applied by spraying, the thickness of this layer can be controlled very easily. The thickness of the layer determines, inter alia, also the strength of the permanent magnets produced subsequently.
The permanent magnet material is preferably sprayed on in the form of a powder. In the case of thermal spraying, the individual powder grains are then on the one hand bonded to the surface of the base member and on the other hand also to each other. This produces a very stable bond of the powder on the surface of the base member. Moreover, such a powder is easy to handle, so that it is possible to build up a layer with relatively little effort.
Advantageously, the powder has a grain size in the range from 0.1 to 200 μm, especially from 1 to 10 μm. With such a grain size a very stable and cohesive structure of the layer of the permanent magnet material can be observed.
NdFeB is preferably used as the permanent magnet material. This material has very good magnetic properties, for example, a large energy density. The use of NdFeB as rotor magnet material is known per se. Until now, however, it has been used in shell or bar form, these shaped bodies being produced by sintering, hot-pressing, or by polymer compounds. It has now been discovered that this material is excellently suited to being sprayed on in powder form if a thermal process is used for that purpose, that is, if heat is supplied at the same time as spraying takes place.
The base member is advantageously subjected to a heat treatment after the permanent magnet material has been sprayed on. During the thermal spraying, a structural change of the permanent magnet material may in fact take place. This can be critical, for example, when the starting powder is crystalline, but after being sprayed on has an amorphous structure. If, for example, NdFeB is used, the constituents Fe and Nd in the starting powder have an intermetallic bond with one another which is able to disintegrate after the thermal spraying. This structural change may possibly render the material no longer directly magnetizable. The heat treatment that can be carried out, for example, in the case of NdFeB, in a temperature range between 800° and 900°, to a great extent restores the crystalline structure of the sprayed-on layer. This renders subsequent magnetization of the base member possible.
The heat treatment is preferably effected in a non¬ oxidizing atmosphere. In this manner the sprayed-on layer is prevented from oxidizing during the heat treatment.
Advantageously, the thermal process is in the form of high-speed spraying or plasma-spraying. With plasma spraying, very high temperatures are reached; the powder need be subjected to these temperatures only very briefly, however. The grains of the powder then fuse at their surface. This produces a very good cohesive strength of the layer in itself and with the base member, without the structure of the permanent magnet material used being destroyed any more than necessary. Plasma spraying of such materials is known from EP 0 339 767 A2. That publication also discloses how such a method is carried out.
It is especially advantageous for the plasma spraying to be carried out at a temperature in the range from 5,000° to 15,000°C. Good results were observed at these temperatures.
Advantageously, the surface of the base member is roughened prior to the spraying operation. This increases the strength of the bond between the sprayed- on permanent magnet material and the base member. Once the first layer of permanent magnet material has been applied to the base member, the surface of the base member is in any case rough, so that subsequent layers are likewise firmly held. In a very especially preferred construction, provision is made for the surface of the permanent magnet material to be made smooth after the spraying operation, in particular by grinding. After the spraying operation, the surface of the base member, or more accurately, the surface of the permanent magnet material, has a rough surface, which has "valleys" and "peaks". There is here probably a danger that during magnetization the "molecular magnets" become oriented in such a way that their actions virtually cancel each other out. In that case only very weak magnetism occurs. If, on the other hand, the surface is made smooth, all "molecular magnets" are oriented in the direction of the magnetic field applied and persist in that orientation so that the desired strong magnetization is produced. (The term "molecular magnets" is here used for reasons of clarity) .
Preferably, the base member is made of metal, in particular soft iron. Besides the well-known good magnetic properties of such a material, the use of a metal, especially soft iron, has the advantage that the sprayed-on layer of permanent magnet material holds firmly thereto, because by virtue of the elevated temperature it is virtually welded to the base member.
The base member is advantageously in the form of a rotor of an electrical machine. This is one of the most important areas of application of the manufacturing method.
The rotor is advantageously turned during the spraying operation. On being sprayed, the rotor is therefore subjected to a uniformly rotary movement. Even when the permanent magnet material is supplied from only one position, it is possible in this manner to form a relatively uniform and homogeneous layer, in which the permanent magnets are later produced. This layer is formed from many partial layers which are, as it were, wrapped around the rotor. The thickness of the layer can be adjusted relatively easily by changing the number of revolutions of the rotor and/or the rotational speed of the rotor. In a nutshell, the spraying time is changed. After spraying, a layer thickness of the order of magnitude of 1 mm is typical.
The permanent magnet material is preferably provided with a protective layer after being sprayed on. Such a protective layer protects the permanent magnet material against oxidation, for example.
The problem is solved in a rotor of an electrical machine in that the permanent magnets are formed in a sprayed-on layer of permanent magnet material. Such a layer holds, as explained above in connection with the manufacturing process, very firmly to the rotor and also forms in itself a relatively strong and thus resistant cohesive bond so that the rotor is able to withstand stress relatively well.
The invention is described hereinafter with reference to a preferred embodiment in conjunction with the drawings, in which:
Fig. l shows a base member for a rotor,
Fig. 2 shows the rotor, which is provided with a layer of permanent magnet material, Fig. 3 shows the rotor in plan view, Fig. 4 shows the rotor in longitudinal section, Fig. 5 shows an electron micrograph of NdFeB in a powder state and Fig. 6 shows an electron micrograph of NdFeB after it has been sprayed on. Fig. 1 shows a rotor 1 of an electrical machine in its unfinished state. Either the rotor 1 is in the form of a solid body of soft iron or it consists of laminations stacked one on top of the other, between which insulators are provided in order to avoid the formation of eddy currents. The construction of the rotor 1 as a base member is not significant for the following description, however. The rotor 1 has a central bore 2 which later serves to receive a rotor shaft.
The rotor 1 has a circumferential surface 3 which has been roughened, for example, by sand-blasting or grinding. A layer 4 of a permanent magnet material, in this case NdFeB, is applied to the circumferential surface 3, as can be seen in Fig. 2. This permanent magnet material is preferred because of its good magnetic properties, in particular its great energy density. Other materials also can be used, however, for example, samarium cobalt, ferrites or rare earths.
The layer 4 can be provided with a further protective layer 5 in order to avoid oxidation.
The rotor is made as follows. NdFeB powder, which is shown on an enlarged scale by an electron micrograph in Fig. 5, is applied to the surface 3 of the rotor 1 by plasma spraying. Plasma spraying is known per se and belongs to the category of thermal spraying in which the powder can be applied at a high temperature to the surface 3 of the rotor 1. To carry out the plasma spraying, the NdFeB powder is heated in a plasma spraying apparatus to a plasma at a temperature in the typical range from 5,000° to 15,000°C, whereupon the surface of the powder material fuses. The powder is then sprayed onto the rotor 1 which rotates steadily during the spraying so that the layer is sprayed on uniformly. Fig. 2 shows the rotor 1 after spraying. The NdFeB layer 4 is shown hatched.
The thickness of the layer 4 can be changed in a simple manner by prolonging or shortening the spraying time. For example, the rotor 1 can be turned more quickly or more slowly or a greater number of revolutions can be performed.
The typical thickness of the layer 4 after spraying is about 1 mm. Alternatively, it can vary in a range from a few μm to several mm.
It has been found that through plasma spraying, with the same magnetic output of the rotor less NdFeB material needs to be applied than would be the case with preformed parts. This is possibly connected with the fact that the density of the permanent magnet material can now be controlled very much more precisely. It is probable too that air gaps between the rotor and the layer are avoided.
The NdFeB powder can have a grain size in the range from 0.1 μm to 200 μm. Preferably, however, a grain size in the range from 1 μm to 10 μm is used.
Because of the high temperature that is used in plasma spraying, the individual particles or grains of the powder are welded during spraying partly to the surface 3 of the rotor and partly to other particles. This welding produces a very good cohesive strength of the powder in itself and of the powder with the surface 3 of the rotor. As a consequence, the rotor 1 can also be exposed to relatively high speeds of rotation, the layer 4 being subjected to correspondingly large centrifugal forces. During plasma spraying of the NdFeB material, however, there is a structural change. The starting material is crystalline. After the spraying, however, an amorphous structure can be observed. In the starting powder the constituents Fe and Nd have an intermetallic bond with one another which in many cases disintegrates after the plasma spraying. This is recognizable in Fig. 6, for example. The result of this change from a crystalline structure to an amorphous structure is that the material can no longer be directly magnetized. In order to recreate the crystalline structure of the sprayed-on material, the rotor 1 is exposed to a heat treatment with the sprayed-on material at a temperature around 800° to 900°C, for example 850°C. By that means the crystalline structure of the starting material is recreated. Subsequent magnetization of the rotor is then possible.
After the plasma spraying operation, the surface of the layer 4 is relatively rough. When such a surface is magnetized, in many cases the magnetism produced is only weak. This is attributable to the fact that the "molecular magnets" are able to orientate themselves in such a way that their actions virtually cancel each other out. To avoid this effect, the surface of the layer 4 is made smooth by grinding off a thin layer of the order of magnitude of about 0.1 mm, or by polishing.
Both the heating and the smoothing operations are effected preferably in an atmosphere that prevents oxidation. Otherwise, in particular when using NdFeB, the risk of oxide formation is relatively high.
The protective layer 5 can be applied after the smoothing operation. The rotor is then ready for magnetization and can be provided with the desired number of poles. For example, magnetization of the rotor can be effected with a magnetic field strength of 3200 kA/m. Alternatively, the magnetic field strength can be varied according to need.
The protective layer 5 can, of course, also be applied after magnetization.
Several advantages can be achieved with the described procedure. First of all, a relatively simple manufacturing process with few work steps is achieved. Secondly, a more robust rotor is produced, since fewer parts are present in the rotor and the magnets are very reliably mechanically fixed to the base member of the rotor. Thirdly, by varying the spraying time and the magnetization current, different rotors can be matched to the required specifications relatively quickly, that is, individual rotors can be tailored to requirements. Finally, compared with conventional manufacturing processes, a saving on the amount of permanent magnet material can be achieved.
As stated at the outset, the method is not restricted to the manufacture of rotors for electrical machines. It is possible also, of course, to produce armatures and stators of linear motors. Sensors having magnetic poles tailored to requirements can be made. Valves or other actuating elements with permanent magnets can also be manufactured in this manner.

Claims

Patent Claims
1. A method of producing magnetic poles on a base member, characterized in that a permanent magnet material is sprayed onto the base member by a thermal process and is subsequently magnetized.
2. A method according to claim 1, characterized in that the permanent magnet material is sprayed on in the form of a powder.
3. A method according to claim 2, characterized in that the powder has a grain size in the range from 0.1 to 200 μm, especially from 1 to 10 μm.
4. A method according to one of claims 1 to 3, characterized in that NdFeB is used as permanent magnet material.
5. A method according to one of claims 1 to 4, characterized in that the base member is subjected to a heat treatment after the permanent magnet material has been sprayed on.
6. A method according to claim 5, characterized in that the heat treatment is effected in a non-oxidizing atmosphere.
7. A method according to one of claims 1 to 6, characterized in that the thermal process is in the form of high-speed spraying or plasma-spraying.
8. A method according to claim 7, characterized in that the plasma spraying is carried out at a temperature in the range from 5,000° to 15,000°C.
9. A method according to one of claims 1 to 8, characterized in that the surface of the base member is roughened prior to the spraying operation.
10. A method according to one of claims 1 to 9, characterized in that the surface of the permanent magnet material is made smooth after the spraying operation, in particular by grinding.
11. A method according to one of claims 1 to 10, characterized in that the base member is made of metal, in particular soft iron.
12. A method according to one of claims 1 to 11, characterized in that the base member is in the form of a rotor of an electrical machine.
13. A method according to claim 12, characterized in that the rotor is turned during the spraying.
14. A method according to one of claims 1 to 13, characterized in that after being sprayed on the permanent magnet material is provided with a protective layer.
15. Rotor of an electrical machine, which rotor has poles that are formed by permanent magnets, characterized in that the permanent magnets are formed in a sprayed-on layer (4) of permanent magnet material.
PCT/DK1996/000358 1995-08-30 1996-08-28 Method of producing magnetic poles on a base member, and rotor of an electrical machine WO1997008716A1 (en)

Priority Applications (1)

Application Number Priority Date Filing Date Title
AU67331/96A AU6733196A (en) 1995-08-30 1994-08-28 Method of producing magnetic poles on a base member, and rotor of an electrical machine

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
DE1995131861 DE19531861A1 (en) 1995-08-30 1995-08-30 Method for producing magnetic poles on a base body and rotor of an electrical machine
DE19531861.7 1995-08-30

Publications (1)

Publication Number Publication Date
WO1997008716A1 true WO1997008716A1 (en) 1997-03-06

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DE (1) DE19531861A1 (en)
WO (1) WO1997008716A1 (en)

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US7075203B2 (en) 2003-02-14 2006-07-11 Minebea Co., Ltd. Electric motor and method for producing a rotor for such an electric motor
US7391203B2 (en) * 2003-09-26 2008-06-24 Siemens Aktiengesellschaft Magnetic field sensor

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US7244512B2 (en) 2001-05-30 2007-07-17 Ford Global Technologies, Llc Method of manufacturing electromagnetic devices using kinetic spray
US6592935B2 (en) * 2001-05-30 2003-07-15 Ford Motor Company Method of manufacturing electromagnetic devices using kinetic spray
DE10135019A1 (en) * 2001-07-18 2003-01-30 Bosch Gmbh Robert Electric motor with permanent magnet excitation
DE102005056823A1 (en) * 2005-11-23 2007-05-31 Deutsches Zentrum für Luft- und Raumfahrt e.V. Fabrication method e.g. for electric machine permanent magnet rotor, involves applying one or more permanent magnetic regions on magnetic support/carrier
DE102009024014A1 (en) * 2009-06-05 2010-12-09 Minebea Co., Ltd., Miyota-machi Rotor for permanent magnet motor, has shaft and rotor body which is connected with shaft in rotably fixed manner, where anisotropic multipolar drive magnet is formed at rotor body
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