DE102013221965A1 - Process for producing a molded part and electric machine with such a molded part - Google Patents

Abstract

The invention relates to a method for producing a molded part, for example a rotor and / or stator for an electric machine, comprising the following steps: positioning (6) a soft magnetic powder composite material (3) in a mold (2), pressing the content of the mold (2 ) To a green compact and tempering of the green compact to a mechanically bonded molding. According to the invention, hard pressed powder composite material (4) and / or non-magnetic powder composite material (5) is positioned (7, 8) in a region of the die (2) separated from the soft magnetic powder composite material (3) prior to pressing. The invention further relates to an electric machine with a rotor and a stator, wherein the rotor and / or the stator is formed as a molded part at least partially made of a soft magnetic powder composite material (3). According to the invention, it is provided that the molded part consists of a hard-magnetic powder composite material (4) and / or nonmagnetic powder composite material (5) in at least one spatially limited area.

Description

The invention relates to a method for producing a particular magnetizable molding, for example a rotor and / or stator for an electrical machine, comprising the steps of: positioning a soft magnetic powder composite in a mold, pressing the contents of the mold into a green compact and tempering the green compact into one mechanically solidified molding.

Furthermore, the invention relates to an electrical machine having a rotor and a stator, which carries the winding, wherein the rotor and / or the stator is formed as a molded part at least partially made of a soft magnetic powder composite material.

A method of the type mentioned is already in the document DE 102 45 088 B3 described. The subject of the document are a powder metallurgically produced soft magnetic molding with high maximum permeability and a method for producing this molded part from metallic powder particles. In order to reduce eddy current losses in alternating fields, as can occur, for example, in high-speed solenoid valves, the powder particles are provided with an electrical insulation layer.

The publication DE 41 05 352 A1 discloses an electric machine having a rotating rotor and a stator supporting the winding, wherein the rotor and / or the stator is formed as a metal powder compact and the powder composite substantially of soft magnetic, provided on all sides with a thin electrically insulating layer, high permeability metal particles and Binders exists. Furthermore, admixture of glass fibers, carbon fibers, ceramic fibers or plastic fibers to the powder composite is taught.

Finally, by the document DE 10 2010 062 722 A1 a rotor of an electric machine is described, which has a permanent magnet provided with iron to enable a required in operation magnetic field line. The iron core is usually formed of a soft iron material and may, for example, punched parts made of sheet metal or a powder metallurgically pressed body. The magnets can be arranged both on the lateral surface of an associated iron core and in cavities formed thereon. As corrosion protection, the rotor has at least sections of a plasma coating. The permanent magnets are preferably sunk or inserted in a so-called buried arrangement formed in the soft iron body, pocket-like recesses and secured therein.

The attachment of the permanent magnets to the soft iron body is often done by gluing. Due to the different thermal expansion coefficients of adhesive, permanent magnets and soft iron body, this compound, in particular in terms of their durability, disadvantageous. The additionally expected high centrifugal forces increase the disadvantages.

A firmer and more durable connection between permanent magnet and soft iron body is achieved, for example, by pressing the permanent magnets into the pocket-like recesses of the soft iron body.

Against this background, the invention has the object to perform a method and an apparatus of the type mentioned above such that an alternative to the prior art is found. This should eliminate the significant disadvantages of the prior art and open up further advantages.

This object is achieved by a method according to the features of claim 1. The subclaims relate to particularly expedient developments of the invention.

According to the invention, therefore, a method for producing a magnetizable molded part is provided in which hard-magnetic powder composite material and / or nonmagnetic powder composite material is positioned before being pressed into regions of the mold that are separate from the soft magnetic powder composite material. Subsequently, the soft magnetic powder composite material is then pressed together with the hard magnetic powder composite material and optionally non-magnetic powder composite material to form a green compact. In this case, but at the latest when the tempering of the green body, a positive and cohesive connection of the different powder composite materials is achieved. This can be dispensed with the disadvantageous additional connecting means such as adhesives. At the same time, the production of complicated spatial structures, in particular asymmetrical magnet shapes, is facilitated by this production method.

So that the different powder composite materials do not mix unnecessarily during positioning, it has proven to be expedient that at least one template is arranged in the mold before positioning at least one of the powder composite materials. This makes it possible to position the powder composite materials in separate areas. Before pressing, the removed at least one template from the mold. It is thereby achieved that the adjoining metal particles of the different regions join together during pressing and / or during tempering.

The positioning of the preferably free-flowing or pasty powder composite materials is ideally carried out by means of at least one nozzle. The powder composite materials are positioned in layers and / or in traces and / or in grid areas in the mold. In particular, when positioning the powder composites in small quantities, layers, tracks or gridwise can be dispensed with a use of a template. The structure of the tracks, layers or matrix areas also adjacent different powder composite materials takes place here in all directions.

When using at least one template, it is advantageous that the different powder composite materials are positioned one after the other in the mold. In this case, the soft magnetic powder composite material, then the nonmagnetic powder composite material and finally the hard magnetic powder composite material are preferably positioned first.

Alternatively, it has proved to be just as favorable, in particular in the absence of stencils, to position the powder composite materials simultaneously in their separate areas in the mold. For this purpose, at least one nozzle is used for each of the different powder composite materials.

The positioning of the powder composite materials, in particular in the areas defined by templates, can be carried out by pouring, for example, free-flowing powder composite materials. For an exact dosage and positioning of the powder composite materials, however, the use of nozzles has proven to be useful. Preferably, the nozzles are moved by a motion machine in three-dimensional space for a control program.

The delivery of the powder composite material from a nozzle can be discontinuous or continuous. In this case, individual layers of the powder composite in the mold are constructed by the movement of the nozzle of tracks and / or raster areas, wherein each track can also be composed of a plurality of screen areas. In this case, a portion amount of one of the different powder composite materials is assigned to an individual grid area.

The preparation of the magnetizable molding can be done by the positioning of all required powder composite materials and a subsequent pressing of these powder composites.

However, it has proven to be particularly favorable that the molded part, or before the tempering of the green compact, is produced in several steps, each step consisting of the positioning of a subset of the powder composite materials and the pressing of the subset in the mold. After pressing the subset, a further subset of the powder composite materials is positioned in the mold. If appropriate, at least one template is arranged in the mold for the positioning of one or more subsets of the powder composite materials. The production of the molded part in several steps makes it possible for the first time to produce complicated spatial structures, in particular of the hard magnetic material surrounded by soft magnetic material, in a simple manner and with virtually any desired geometry. Thus, asymmetrical magnet shapes, undercuts and staggered areas can be modeled.

The sections of the molded part constructed by individual steps or in several steps form a preferably axial segmentation. The sections made up of one or more layers and / or in one or more steps are therefore referred to as segments. To produce, for example, a rotor bevel, the segments have an angular offset from each other. The rotor pitch reduces the harmonics and thus increases the power of the electric machine.

Preferably, the tempering takes place before a molding of the molded part from the mold. For an acceleration of the manufacturing process and in particular for achieving increased strength in a multi-step structure of the molded part, it has been found to be particularly practical that the pressing and the tempering take place simultaneously, for example as so-called hot pressing.

The object is further achieved with a device according to the features of claim 8. The dependent claims relate to particularly expedient developments of the invention.

According to the invention, therefore, an electric machine is provided in which the molded part consists of a hard-magnetic and / or nonmagnetic powder composite material in at least one spatially limited area. Due to the structure of the molded part of soft magnetic and hard magnetic powder composite materials in space limited areas, a high strength of the molded part can be achieved.

The introduction of non-magnetic powder composite material in limited areas serves to influence the magnetic field. In the prior art cavities are provided in the molded part, which, however, adversely affect its strength. Due to the non-magnetic powder composite, which is positively and materially bonded to the other powder composite materials, an increase in the magnetic resistance, that is to say the reluctance, is achieved and, at the same time, the strength of the molded part is improved. As a non-magnetic powder composite material, for example, paramagnetic and / or diamagnetic composite materials are used.

It is preferably provided that the region of a nonmagnetic powder composite material bears against a region of soft magnetic powder composite material and on a region of hard magnetic powder composite material.

Another favorable embodiment of the molding provides that this consists in particular in the axial direction of several segments. It is particularly favorable that these segments have an angular offset from each other. As a result, a rotor bevel is achieved to reduce the harmonics, which improves the performance of the electric machine.

Furthermore, it is advantageous that the device has been produced by a method according to at least one of the aforementioned features, in particular according to at least one of the features of claims 1 to 7.

The invention allows numerous embodiments. To further clarify its basic principle, some of them are shown in the drawing and will be described below. This shows in

1 a schematic representation of a process step of a method for producing a magnetizable molding;

2 a schematic representation of a further process step of the method for producing a magnetizable molding;

3 a schematic representation of a further process step of the method for producing a magnetizable molding;

4 a schematic representation of a first embodiment of the molding according to the invention;

5 a schematic representation of a second embodiment of the molding according to the invention;

6 a schematic representation of the positioning of a powder composite in a track;

7 a schematic representation of the positioning of a powder composite in a grid area;

8th a schematic representation of the positioning of a powder composite in a track with grid areas;

9 a schematic representation of the positioning of a powder composite in several layers.

The 1 to 3 show different process steps of a process for producing an in 4 illustrated molding 1 , For example, a rotor and / or stator for an electric machine. In a mold 2 become different powder composite materials 3 . 4 . 5 positioned 6 . 7 . 8th , To mix the different powder composites 3 . 4 . 5 in the positioning 6 . 7 . 8th to avoid were in the mold 2 template 9 disposed 10 , At the in 1 First, the non-magnetic powder composite materials were shown 5 as pre-connected body in the mold 2 positioned 8th as well as the templates 9 in the mold 2 disposed 10 , Shown is how then the hard magnetic powder composite material 4 in the templates 9 positioned 7 and the soft magnetic powder composite 3 in the remaining cavity of the mold 2 positioned 6 becomes.

Subsequently, as in 2 shown, the templates 9 from the mold 2 away 11 , Then, as in 3 shown, the content of the mold 2 pressed to a green compact 12 and tempered at the same time 13 , wherein the powder composite materials 3 . 4 . 5 to a mechanically consolidated molding 1 connect. Finally, before or after the molding of the molding, not shown 1 from the mold 2 the molding 1 magnetized 15 , The finished product, a molded part 1 , is in 4 shown in a first embodiment.

5 shows a further embodiment of the molded part 1 , This consists of several segments 16 which have an angular offset from each other in the axial direction. The angular offset is achieved by firstly that the molded part 1 is generated in several steps, with each step from the positioning 6 . 7 . 8th a subset of the powder composite materials 3 . 4 . 5 and the pressing 12 of the Subset in the mold 2 consists. Second, the templates become 9 every time you move to a new location in the mold 2 disposed 10 , In this case, the new point with respect to the previous with an angular offset about the axis of rotation of the molded part 1 twisted.

The 6 to 9 show an example of the positioning 6 . 7 . 8th from one of the powder composite materials 3 . 4 . 5 by means of at least one nozzle 17 , In 6 is the positioning 6 . 7 . 8th single tracks 18 shown in a continuous discharge of the powder composite 3 . 4 . 5 be generated. 7 shows the possible production of screen areas by means of discontinuous delivery 19 with different powder composites 3 . 4 , The traces 18 can like in 8th also shown in grid areas 19 be constructed. The powder composite materials 3 . 4 . 5 are in the mold 2 in several layers 20 arranged one above the other as is through 9 is illustrated.

LIST OF REFERENCE NUMBERS

1

molding

2

mold

3

soft magnetic powder composite material

4

hard magnetic powder composite material

5

non-magnetic powder composite

6

Positioning of 3

7

Positioning of 4

8th

Positioning of 5

9

template

10

Arrange the template

11

Remove the template

12

Press

13

temper

14

15

Magnetize

16

segment

17

jet

18

track

19

screen range

20

location

QUOTES INCLUDE IN THE DESCRIPTION

This list of the documents listed by the applicant has been generated automatically and is included solely for the better information of the reader. The list is not part of the German patent or utility model application. The DPMA assumes no liability for any errors or omissions.

Cited patent literature

• DE 10245088 B3 [0003]
• DE 4105352 A1 [0004]
• DE 102010062722 A1 [0005]

Claims (10)

Process for producing a molded part ( 1 ), for example a rotor and / or stator for an electric machine, comprising the following steps: positioning ( 6 ) of a soft magnetic powder composite material ( 3 ) in a mold ( 2 ), Pressing ( 12 ) of the content of the mold ( 2 ) to a green body and tempering ( 13 ) of the green compact to a mechanically solidified molded part ( 1 ), characterized in that before pressing ( 12 ) in the soft magnetic powder composite material ( 3 ) separate areas of the mold ( 2 ) hard magnetic powder composite material ( 4 ) ( 7 ) and / or nonmagnetic powder composite material ( 5 ) ( 8th ) becomes. Process for producing a magnetizable molded part ( 1 ) according to claim 1, characterized in that before positioning ( 6 . 7 . 8th ) of a powder composite material ( 3 . 4 . 5 ) at least one template ( 9 ) in the mold ( 2 ) ( 10 ) and the template ( 9 ) before pressing ( 12 ) from the mold ( 2 ) away ( 11 ) becomes. Process for producing a magnetizable molded part ( 1 ) according to claims 1 or 2, characterized in that the powder composite materials ( 3 . 4 . 5 ) in layers ( 20 ) and / or in tracks ( 18 ) and / or in raster areas ( 19 ) in the mold ( 2 ) ( 6 . 7 . 8th ) become. Process for producing a magnetizable molded part ( 1 ) according to at least one of the preceding claims, characterized in that the different powder composite materials ( 3 . 4 . 5 ) successively in the mold ( 2 ). Process for producing a magnetizable molded part ( 1 ) according to at least one of the preceding claims, characterized in that at least one of the layers ( 20 ) from traces ( 18 ) and / or grid areas ( 19 ) and / or at least one track ( 18 ) from a plurality of grid areas ( 19 ) is composed. Process for producing a magnetizable molded part ( 1 ) according to at least one of the preceding claims, characterized in that before the tempering ( 13 ) is produced in several steps of the green compact, each step from the positioning ( 6 . 7 . 8th ) a subset of at least one of the powder composite materials ( 3 . 4 . 5 ) and pressing ( 12 ) of the subset in the mold ( 2 ) consists. Process for producing a magnetizable molded part ( 1 ) according to at least one of the preceding claims, characterized in that the pressing ( 12 ) and tempering ( 13 ) at the same time, in particular before shaping. Electric machine with a rotor and a stator, wherein the rotor and / or the stator as a molded part ( 1 ) at least partially made of a soft magnetic powder composite material ( 3 ) is formed, characterized in that the molded part ( 1 ) in at least one spatially limited area of a hard magnetic powder composite material ( 4 ) and / or non-magnetic powder composite material ( 5 ) consists. Electric machine with a molded part ( 1 ) according to claim 8, characterized in that the region of a non-magnetic powder composite material ( 5 ) at a region with soft magnetic powder composite material ( 3 ) and at a region with hard magnetic powder composite material ( 4 ) is present. Electric machine with a molded part ( 1 ) according to at least one of claims 8 and 9, characterized in that the molded part ( 1 ) has been prepared by a method according to at least one feature of claims 1 to 7.

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