DE19804488A1 - Electrical machine with stator and rotor - Google Patents

Abstract

At least two permanent magnet segments (3) assigned to one of the magnetic poles (25) are designed in one-piece fashion, connected by a connecting section. The connecting section extends only over a break-off part of the connected bounding sides of the magnet segments. The width of the individual magnet segments is a multiple of the height of the segments. The connecting section has an extension increasing the height of the magnet segments for spacing away the segments joined together by the connecting section.

Description

The invention relates to an electrical machine according to the preamble of the patent saying 1.

It already includes a stator and a rotor equipped with permanent magnets de electrical machines known. For powerful, small installation space Talking electrical machines are used to provide high rotors Field strength equipped with magnets with a high energy density, for example with Neodymium-iron-boron magnets from Vac Vacuumschmelze GmbH with the name Vaco dym called. Magnets made from this material provide a high magnetic field low volume ready. So that there is no eddy current loss, or sol che losses are minimal, permanent magnets with small dimensions in min at least one direction used perpendicular to the direction of magnetization. Several these permanent magnet segments become a magnetic block by means of a duration Adhesive magnet segments from each other glued together or with Ab stood glued to each other. A rotor equipped with permanent magnet segments is included for example on page 7 of the company brochure of "Rare Earth Permanent Magnets Vacodym, Vacomax "from VAC Vacuumschmelze GmbH from 1996  Segmentation of the permanent period forming a magnetic pole of the electrical machine waive gnete, there is one in operation due to the eddy current losses strong heating of the rotor. As a result of this heating, demagnetization can occur magnetization, which means that the elec machine would go hand in hand or even lead to total failure of the electrical Machine can come.

For these reasons it is necessary to close the magnets from permanent magnet segments form, which is associated with high manufacturing costs. To guarantee The permanent magnet segments demonstrate minimal eddy current losses in one already in the manufacturing process, predetermined preferred direction a minimum le dimension. The permanent magnet segments thus have a pre-magnetization direction, as well as in a direction perpendicular to it almost identical minimum Dimensions on. Due to the almost identical dimensions, it can be manufactured development process easily to a faulty arrangement of individual permanent magnet segments come. If permanent magnet segments are incorrectly arranged, preference is given direction perpendicular to the desired direction. As a result, these are permanent gnet segments almost non-magnetizable during a magnetization process. Info if the individual permanent magnet segments are arranged incorrectly, a minde will work performance of the electrical machine.

The object of the invention is to increase manufacturing reliability and manufacture a rotor that is equipped with magnets with a high energy density, to simplify and thus reduce manufacturing costs.

The object is achieved by the features given in claim 1.

By the measure to provide at least one connecting section through which at least two permanent magnet segments are connected to one another, is a unit, hereinafter referred to as a magnetic module. It is envisaged that over Connecting section connected permanent magnet segments with the Verbindungsab to cut in one piece. By combining at least two durations magnet segments is the direction of the process of manufacturing permanent magnet segments predetermined preferred direction clearly in the direction of the minimum dimension  predetermined preferred direction clearly in the direction of the minimum dimension placed, a confusion due to the design of the permanent magnet mo dules, which comprises at least two permanent magnet segments, is excluded.

The connecting section extends only over a fraction of the ver bound edges of the permanent magnet segments. This area over which the permanent gnet segments in connection has such a minimal cross-sectional area, that the formation of an eddy current in this area due to the chosen minimum dimension is prevented or almost prevented. Are two dhows Magnet segments connected to each other and formed in one piece, so reduced the number of magnets to be glued by half.

In an advantageous embodiment, they are connected via the connecting section those permanent magnet segments by means of a connection exceeding their height cut apart from each other. Providing this distance is permanent gnetsegment can be arranged between the spaced apart permanent magnet segments. It has turned out to be advantageous to combine two permanent magnet modules into one unit add, the permanent magnet segments of the permanent magnet modules, preferably alternating, interlocking.

The one-piece permanent magnet modules are preferably designed in this way det that by rotation through 180 ° and an axial offset by the amount of a duration magnet segment plus a minimum distance to be provided for an electrical Isolation of the permanent magnets from each other to form a cuboid unit available. An electrically insulating adhesive can be provided between the segments be. Since any magnetic forms by using appropriate molds can be produced with little effort, is the realization of the new magnetic forms associated with low costs.

A permanent magnet has been found to be a further advantageous embodiment block with recesses in the form of columns. Through these columns the magnetic block is divided into individual segments, with the segments still each are connected to one another via a connecting section. The columns are in front preferably designed such that the permanent magnet segments through the gap over the  tion material in the gap is therefore not necessary. By providing the verb Sections in the middle of the magnetic block is the fracture sensitivity of the Ma gnetmodule lower, since the force acting on the end of a magnetic segment Force acts on the connecting section via a shorter lever arm.

The invention is described in more detail below with the aid of a few exemplary embodiments ben. Further advantageous measures are described in further subclaims. It shows:

Fig. 1 a formed as an external rotor rotor;

Fig. 2 is a unit formed by two magnetic modules;

Fig. 3 shows a magnetic block formed with columns.

In Fig. 1, the basic structure is shown as an example of a formed as an external rotor the rotor, as well as other internal rotor motors or linear motors can be equipped with permanent magnet modules. Permanent magnets are arranged on the radial inside of the rotor, by means of which magnetic poles 25 are formed. A magnetic pole 25 in turn comprises a plurality of in Fig. 2 and Fig. 3 in more detail dargestell th permanent magnet segments 3.

In the embodiment shown in FIG. 2, a magnet module 13 , which has four permanent magnet segments 3 , is shown. The permanent magnet segments 3 are connected to each other via connection sections 5 provided between them. The connecting sections 5 are designed in the form of webs 6 . The permanent magnet segments 5 of a magnet module 13 are spaced apart from one another by the webs 6 . This distance of the permanent magnet segments 3, the height exceeds a Dauerma gnetsegmentes 3 Of the recesses formed between the permanent magnet segments 3 of 16 are permanent magnet segments of a permanent magnet module 13 further added. Before the permanent magnet modules are put together, it can be seen to introduce an electrically insulating adhesive. After assembling the permanent magnet modules 13 into one unit, it may be necessary to ensure that the front and back surfaces are freed by grinding adhesive residues to ensure smooth upper surfaces. A pole can have several such units.

In Fig. 3a and 3b are shown magnet 13 modules, a plurality of the gnetsegmenten Dauerma comprise from 3. These permanent magnet segments 3 are connected to each other via a connec tion section 5 and are formed in one piece and isolated from one another by the recesses 16 arranged between them in the form of columns 17 . These columns 17 can be produced in a single step, for example after the production of a magnetic block by means of a cutting device. The height 7 of the permanent magnet segments is determined by the distance 18 of the columns 17 from one another.

For example, if a rotor with a length of 120 mm is to be equipped with magnets, one pole can be formed by three magnet units, each 40 mm long the.

Reference list

1

rotor

3rd

Permanent magnet segments

5

Connecting section

6

Walkways

7

height

9

width

11

thickness

13

Magnet module

15

Permanent magnet block

16

Recess

17th

gap

18th

distance

21

Direction of bias

23

Boundary side

25th

Magnetic pole

Claims (9)

1. Electrical machine comprising a stator and a rotor, the rotor being equipped with permanent magnet segments to form magnetic poles, each of the poles each comprising a plurality of permanent magnet segments, characterized in that at least two permanent magnet segments assigned to one of the poles ( 3 ) are connected in one piece by a provided connecting section ( 5 ), the connecting section ( 5 ) extending only over a fraction of the interconnected boundary sides ( 23 ) of the permanent magnet segments ( 3 ). 2. Electrical machine according to claim 1, wherein the width of the individual Dauerma gnetsegmente has a multiple of the height of the permanent magnet segments, characterized in that the connecting section ( 5 ) has a height ( 7 ) of the permanent magnet segments ( 3 ) extending to the spacing of the means of the connecting section ( 5 ) connected permanent magnet segments ( 3 ). 3. Electrical machine according to claim 1, characterized in that through the permanent magnet segments ( 3 ) which are connected to each other via connecting sections ( 5 ), the magnetic modules ( 13 ) are formed and that a magnetic pole ( 25 ) at least two oppositely shaped magnetic modules ( 13 ). 4. Electrical machine according to claim 1, 2 or 3, characterized in that the permanent magnet segments ( 3 ) have a bias ( 21 ) with a preferred direction perpendicular to the thickness of the permanent magnet segments. 5. Electrical machine according to claim 1, characterized in that for the formation of, by means of the connecting portions ( 5 ) interconnected permanent magnet segments ( 3 ), in a permanent magnet block ( 15 ) recesses ( 16 ) in the form of columns ( 17 ) are provided. 6. Electrical machine according to claim 1, characterized in that the height ( 7 ) of the permanent magnet segments ( 3 ) is predetermined by the distance between the columns ( 17 ). 7. Electrical machine according to claim 1 or 2, characterized in that the connecting sections ( 5 ) are designed in the form of webs ( 6 ). 8. Electrical machine according to claim 1, characterized in that the connec tion sections ( 5 ) and the permanent magnet segments ( 3 ) consist of the same material. 9. Electrical machine according to claim 1, characterized in that Magnetmo modules are made by pressing from magnetic powder material and that the permanent magnet segments ( 3 ) and the connecting sections ( 5 ) have a bias in the same direction.