DE102013209186A1 - Component of an electrical machine and method for its production - Google Patents

Abstract

The invention relates to a component (2) for an electrical machine (1), comprising: a carrier body (3); - At least one conductor section (7) embedded in the carrier body (3); - At least one web region (8) formed on the conductor section (7) in the carrier body (3), the at least one web region (8) being designed with a high relative magnetic resistance compared to the rest of the carrier body (3).

Description

Technical area

The invention generally relates to a component of an electrical machine, in particular a rotor of an asynchronous machine.

State of the art

An asynchronous machine, for example, compared to a brush-commutated electric machine allows a high torque density at lower manufacturing and material costs. In addition, asynchronous machines are robust and have a long service life.

In asynchronous motors, a rotating stator field generated by a stator causes voltages to be induced in the short-circuit windings of a rotor. The resulting from the induced voltages generate a magnetic field in an air gap between the rotor and stator, the magnetic field counteracts its cause, namely the rotating stator field. Thus, a force acts on the rotor in the stator field, causing it to rotate.

Today, asynchronous machines are mainly designed with squirrel-cage rotors which have short-circuit windings, in particular made of conductive copper or aluminum material.

The short-circuit windings can be produced in a laminated rotor body by a casting process or used as plug-in windings in the rotor body.

The short-circuit windings may be located in longitudinal grooves of a cylindrical iron body composed of sheet iron disks. Furthermore, the axially extending portions of the short-circuit windings, which form a so-called cage anchor, at the end faces of the rotor with each other, for example by a conductive ring, be short-circuited.

In order to improve the mechanical strength of the rotor, in particular in a rotor for a high speed with a comparatively high mass inertia, the short-circuit windings can be embodied embedded in the rotor body. In this case, a web is formed from the magnetically conductive material of the rotor body in the radial direction between the air gap and an axially extending portion of the short-circuit winding.

Due to the design of the machine can cause magnetic short circuits between adjacent rotor poles, which form between adjacent conductor sides of the short-circuit windings through the web. However, the short-circuited portion of the formed magnetic field does not contribute to the torque generation and thereby reduces the efficiency of the machine.

From the publication WO 90/04281 is a squirrel cage motor for operation with a frequency converter known. A conductor portion of the rotor is received in a groove of the rotor, which opens in the form of a slot to the air gap of the rotor. For magnetic bridging of the slot, a magnetic bridge which is strongly curved towards the rotor conductor is provided.

The publication DE 10 2010 021 470 A1 discloses a squirrel cage rotor for an asynchronous machine and a method of manufacturing the squirrel cage rotor.

It is an object of the present invention to provide a component of an electric machine, in particular a rotor, in particular a component which has a good mechanical strength and an efficient torque generation, and a method for the production thereof.

Disclosure of the invention

This object is achieved by a component for an electric machine according to claim 1 and by an electric machine and by a method for producing a component for an electric machine according to the independent claims.

Further advantageous embodiments of the present invention are specified in the dependent claims.

• – einen Trägerkörper aus einem magnetisch leitfähigen, insbesondere ferromagnetischen Material;
• – mindestens einen in dem Trägerkörper eingebetteten Leiterabschnitt;
• – mindestens einen am Leiterabschnitt in dem Trägerkörper gebildeten Stegbereich, der zwischen dem Leiterabschnitt und einer Oberfläche des Trägerköpers gebildet ist,

wobei der mindestens eine Stegbereich mit einem im Vergleich zu dem Material des übrigen Trägerkörpers hohen relativen magnetischen Widerstand ausgebildet ist.According to a first aspect, there is provided a component for an electric machine comprising:

• - A support body of a magnetically conductive, in particular ferromagnetic material;
• - At least one embedded in the carrier body conductor portion;
• At least one web region formed on the conductor section in the carrier body and formed between the conductor section and a surface of the carrier body,

wherein the at least one web region is formed with a relative to the material of the rest of the carrier body high relative magnetic resistance.

An idea of the above device is to increase the performance of an electric machine by targeted and fine-tuned management of the To provide magnetic flux and in particular to reduce the magnetic flux through the land area.

This can be achieved by locally reducing the magnetic permeability of magnetically conductive material, such as electrical steel, in particular stacked formed electrical steel, which can be referred to as magnetic separation. By generating magnetically impermeable or poorly conductive, but mechanically stable separation regions between the individual rotor segments, magnetic leakage losses can be reduced. As a result, the torque density of the component of the electric machine can be increased.

In addition, this idea allows flexibility in the design of the gap widths and the conductor cross-sections.

In other words, the relative magnetic resistance in the flux bridges or webs can thus be increased by targeted measures without the rotor losing mechanical strength.

The fact that the conductor section is embedded in the carrier body body, it may be possible that the conductor section against a mechanical load, such as a centrifugal force, mechanically retained on the carrier body.

According to one embodiment, the web region can be formed by local application of an introduction material and subsequent local remelting. The introduction material may be defined in its composition so that a range of a non-ferromagnetic material may be formed by jointly melting flux-conducting material of the carrier body and introducing material in the remelted area for the entire interval of temperatures occurring during manufacture, standstill or operation. For example, an austenitic structure that is not ferromagnetic can be set.

To achieve this, the introduction material may have a high content of, for example, nickel, manganese and / or copper. The effect can be increased by additional content of, for example, carbon and / or chromium. Possible ranges of composition of the remelted area may be as follows: Nickel: 0% to 35% Manganese: 0% to 25% Copper: 0% to 10% Aluminum: 0% to 10% Carbon: 0% to 1.0% Chrome: 0% to 25% Rest: iron and steel typical accompanying elements

In particular, the introduction material can be supplied as a belt, wire, rod or powder and the remelting can be effected by laser beam, electron beam, plasma or electric arc. The supply of the introduction material thus takes place, for example, as a strip, wire, rod material or powder before or during melting, wherein the energy input for remelting can be done for example by a known from welding technique, for example laser beam, electron beam, plasma or arc.

Furthermore, the component can be designed such that the introduction material is selected so that the web region is formed by the remelting at least partially porous.

The web region which is at least partially porous may have a high relative magnetic resistance compared to the rest of the carrier body.

For special solutions can be achieved by the melting process at the same time a mechanical connection of individual elements of the flux-conducting material of the carrier body. The remelting can be used particularly advantageously if, at the same time as the magnetic separation, a mechanical connection of individual sheets is also to be realized. By welding in the axial direction otherwise commonly used techniques, such as punching parceling points can be omitted. By pinning the sheets with the introduction material before the welding process, an alignment, packaging and - by the subsequent remelting - a magnetic separation can take place simultaneously.

In particular, rotor laminations may be provided along with a copper coil or aluminum coil to create a zone of greatly reduced magnetic permeability without the need for a seed material.

In order to promote the mixture in the structure and the reproducibility of the relative relative to the rest of the carrier high relative magnetic resistance, process parameters such as feed rate, irradiation angle and number of laser beams used are optimized.

Furthermore, the component can be designed such that the conductor section is provided with a coating which has a boiling temperature which is lower than a melting temperature of the material forming the carrier body. This configuration can reduce magnetic permeability of magnetically conductive material such as electric sheet as follows.

The boiling point of zinc, for example, is 907 ° C. It is known that the fusion welding of galvanized steel components is expected to result in a strong formation of ejections and splashes. Therefore, the conductor sections 7 , which are formed for example of copper or aluminum, coated with zinc prior to installation in the component of the electrical machine.

A melting of the material of the carrier body, that is, for example, the electric sheet material, together with the melting of the galvanized conductor portion by an arbitrary fusion welding process, due to the zinc layer to pronounced ejections and pores in the web area 8th to lead. In this way, there is the desired local reduction of the magnetic permeability and thus a reduction of the magnetic flux in the land area 8th ,

This effect of high ejection and pore formation can also be achieved by other types of coatings, heat treatments, such as nitriding the conductor, or, for example, by using alternative cast aluminum conductors.

Furthermore, the component of the electrical machine can be designed such that on the carrier body, near the conductor section 7 , a notch is provided. In this case, an effect is used that can result in the fusion welding of copper and iron materials or aluminum with iron materials to form pronounced brittle intermetallic phases.

This effect can be exploited as follows to produce a region with reduced magnetic flux: By means of a mechanically rigid design of the electrical sheet material, preferably in the form of a notch in the electrical sheet, reproducible cracks in the weld region can be produced. During a remelting of such a point, for example by a laser beam, high residual stresses can occur in the web region. The result is reproducible cracking. This locally separates the magnetic flux and thus achieves the desired local reduction in magnetic permeability.

According to a further aspect, an electrical machine with the above component is provided, wherein the component is designed in particular as a rotor of the electric machine.

In yet another aspect, there is provided a method of manufacturing a component for an electric machine comprising the steps of: providing a support body having at least one conductor portion embedded therein; Increasing a relative magnetic resistance of a land portion disposed between the conductor portion and a surface of the support body.

One idea of this method is to increase the performance of an electric machine by targeted and fine-tuned conduction of the magnetic flux.

It can be provided that the increase of the relative magnetic resistance is carried out by changing the material of the land area so that it becomes at least partially porous.

According to one embodiment, changing the relative magnetic resistance by local application of a deposition material to the surface on the carrier body near the conductor portion and subsequent local remelting can be achieved.

• – Bereitstellen einer Beschichtung mit einem Einbringmaterial, insbesondere Zink, auf dem Leiterabschnitt, wobei das Einbringmaterial eine Siedetemperatur aufweist, welche niedriger als eine Schmelztemperatur des Materials des Trägerkörpers ist, und
• – anschließendes örtliches Aufschmelzen des Leiterabschnitts mit einer Temperatur über der Siedetemperatur des Einbringmaterials und unter der Schmelztemperatur des Materials des Trägerkörpers, so dass zumindest im Stegbereich eine Zone verringerter magnetischer Permeabilität ausgebildet wird.

In particular, it may be provided that the increase of the relative magnetic resistance is performed by the steps:

• - Providing a coating with a Einbringmaterial, in particular zinc, on the conductor portion, wherein the introduction material has a boiling temperature which is lower than a melting temperature of the material of the carrier body, and
• - Subsequent local melting of the conductor portion having a temperature above the boiling temperature of the Einbringmaterials and below the melting temperature of the material of the carrier body, so that at least in the web area a zone of reduced magnetic permeability is formed.

According to one embodiment, increasing the relative magnetic resistance may be achieved by forming a notch on the surface of the land area near the conductor portion, and then locally fusing at the notch.

Brief description of the drawings

Preferred embodiments of the present invention will be explained in more detail with reference to the accompanying drawings. Show it:

1 a cross section through an electric machine transverse to a rotation axis;

2 a cross section of a detail 1 ;

3a b shows an effect of introducing a burying material for forming the land portion having a high relative magnetic resistance;

4a . 4b and 4c a representation of a method for producing a porous land area;

5a . 5b and 5c an illustration of a method for generating a cracked land area.

Description of embodiments

1 shows a cross section transverse to an axial direction by an electric machine 1 , The electric machine 1 has a rotor 2 (Component) with a circular cylindrical rotor carrier body 3 on, which can rotate about an axis W rotatable. The rotor carrier body 3 is circumferentially with juxtaposed, extending in the axial direction conductor portions 7 provided in the rotor carrier body 3 are embedded. The conductor sections 7 are part of short-circuit windings with a winding plane parallel to the axis W. The conductor sections 7 can be on the front sides of the rotor 2 be short-circuited and form eg a squirrel cage. The conductor sections 7 may have a round or a radially elongated cross-section.

Between the conductor sections 7 the short-circuit windings and a lateral surface UR of the rotor carrier body 3 there is a footbridge area 8th ,

The rotor carrier body 3 is rotatable in a circular cylindrical stator 5 arranged. The stator 5 is circumferentially equally spaced stator teeth 10 provided by Statornuten 9 are separated from each other. The stator teeth 10 are surrounded by stator coils, not shown.

The stator 5 has an inwardly facing surface US through an air gap 11 the width d of the surface UR of the rotor carrier body 3 is disconnected.

2 shows an enlarged section 1 , It can be seen that in the rotor carrier body 3 the conductor sections 7 are shown embedded and thereby a land area 8th between a conductor section on the rotor carrier body and the outer circumference of the rotor carrier body 3 or the air gap 11 is formed, train.

The 3a and 3b illustrate the effect of a in the web area 8th with a compared to the material of the rotor carrier body 3 increased relative magnetic resistance. For better clarity, field lines of magnetic flux density B are shown here. A flux φ results from the magnetic flux density B.

In 3a is a section of the rotor carrier body 3 the electric machine 1 shown. In the rotor carrier body 3 is a ladder section 7 embedded with a flow direction of a current I perpendicular to the drawing plane. Between a surface UR, which is an outer periphery of the rotor carrier body 3 represents and the ladder section 7 there is a bridge area 8th , Opposite the rotor carrier body 3 is a stator 25 arranged, whose the rotor carrier body 3 assigning surface US, the inner circumference US of the stator 25 corresponds, at a distance d of an air gap 11 arranged.

The bridge area 8th may preferably be integral with the rest of the rotor carrier body 3 be formed, for example, stacked ferromagnetic sheets which are electrically isolated from each other to avoid eddy currents in the operation of the electric machine. In this case, if there is a current through the conductor section 7 flows, the field lines of the magnetic induction B partially through the land area 8th of the rotor carrier body 3 and partly over the air gap 11 through the stator 25 , The within the rotor carrier body 3 However, extending field lines do not contribute to torque formation on the rotor and are therefore undesirable.

3b shows that instead of the bridge area 8th of the 3a a dock area 12 is provided, which is formed of a material having a high relative magnetic resistance. Because of this, the magnetic flux density B 'is in the land area 12 now significantly reduced and the proportion of the magnetic flux density B ', in the representation of the 3a still through the bridge area 8th has run, now passes through the air gap 11 in the stator 25 , One effect is that a greater proportion of the magnetic flux density B 'can contribute to the torque generation of the electrical machine.

The change in the material of the land area 12 For example, it can be made by supplying an introduction material from the outside, for example as a tape, wire, rod material or powder. Before or during the feeding of the introduction material, the web region is melted. The energy input for melting can be carried out by a known from welding technology, for example, using a laser beam, electron beam, plasma or arc.

The 4a . 4b . 4c illustrate increasing the relative magnetic resistance in the land region 8th ,

4a shows a portion of a rotor carrier body 3 an electric machine. In this rotor carrier body 3 is a ladder section 7 embedded. Between the ladder section 7 and an outer surface UR of the rotor carrier body is a land portion 8th arranged. The ladder section 7 can with a coating 34 be covered. The coating may consist of a material which has a lower boiling temperature than a melting temperature of the material forming the carrier body 3 is. For example, for the coating 34 the material zinc be provided, which has a boiling point of 907 ° C.

Will the bridge area 8th , as in 4b is shown, for example, irradiated with a strong laser radiation L, so is the land area 8th and the underlying portion of the conductor section 7 heated so that, as in the enlarged section A of the 4c is shown, a porous or porous web area 32 forms, which has a significantly increased magnetic resistance.

The fusion welding of galvanized steel components can lead to the formation of ejections and splashes. If the conductor sections are formed, for example, from copper or aluminum, they can be coated with zinc prior to installation in the component of the electrical machine, in particular the rotor of an asynchronous machine. A melting of the material of the land area 8th together with the melting of the galvanized conductor by any arbitrary local melting process can lead to pronounced ejections and pores due to the zinc layer, which proceeding from the conductor section 7 in the dock area 8th extend. In this way, there is an increase in the relative magnetic resistance and thereby a reduction of the magnetic flux through the land area 8th ,

In this way, the field line displacing effect corresponding to the 3a and 3b be achieved.

The 5a . 5b . 5c illustrate an alternative or additional possibility, the relative magnetic resistance of the land area 8th to increase.

5a shows a rotor carrier body 3 an electric machine 1 , In the rotor carrier body 3 is a ladder section 7 embedded. Between a surface UR of the rotor carrier body 3 and the ladder section 7 is a dock area 8th arranged. In this dock area 8th becomes a notch 6 intended.

5b illustrated enlarged in the 5c , the effect of a high energy laser beam directed at this indentation. The laser beam causes a local fusion welding in the area of the web area 8th between the material of the conductor section 7 and the material of the rotor carrier body 3 , In some embodiments, this may be fusion welding a conductor portion formed of copper 7 with a ferrous material or fusion welding a ladder section formed of aluminum 7 be with an iron material.

It is known that such a fusion welding of different metals together can lead to the formation of very brittle intermetallic phases.

By fusion welding of the two materials mentioned, ie copper with a ferrous material or aluminum with a ferrous material, at the location of the notch 6 Thus, reproducible cracks in the welding area can be produced. As a result, the magnetic flux in the region of the crack formation is separated, so that a land area 42 with respect to the material of the rest rotor carrier body 3 locally increased relative magnetic resistance was achieved.

Furthermore, it can be provided, when using a coated conductor portion, additionally apply a Einbringmaterial from the outside. It can also be provided, in addition to provide a notch when using provided with a coating conductor section and then melt them. Finally, a combination of all three variants can be provided.

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

• WO 90/04281 [0009]
• DE 102010021470 A1 [0010]

Claims (14)

Component ( 2 ) for an electric machine ( 1 ), comprising: - a carrier body ( 3 ) of a magnetically conductive, in particular ferromagnetic material; At least one in the carrier body ( 3 ) embedded electrical conductor section ( 7 ); At least one on the conductor section ( 7 ) in the carrier body ( 3 ) formed web area ( 8th ) located between the conductor section ( 7 ) and a surface (UR, US) of the carrier body (US Pat. 3 ), wherein the at least one web region ( 8th ) with a compared to the material of the rest of the carrier body ( 3 ) is formed high relative magnetic resistance. Component ( 2 ) according to claim 1, wherein the land area ( 8th ) is formed by a Einbringmaterial is applied locally and then a local remelting is performed. Component ( 2 ) according to claim 1 or 2, wherein the land area ( 8th ) is formed by the introduction material is supplied as a ribbon, wire, rod material or powder and the remelting by laser beam, electron beam, plasma or arc is performed. Component ( 2 ) according to claim 1 to 3, wherein the introduction material is selected, in particular as copper material or aluminum material, that of the particular formed of a ferrous material web area ( 8th ) is formed by the remelting with an at least partially porous intermetallic phase. Component ( 2 ) according to claim 1 to 4, wherein the introduction material is selected such that the web region ( 8th ) is formed by the remelting at least partially with an austenitic structure. Component ( 2 ) according to one of claims 1 to 5, wherein the at least one conductor section ( 7 ) when embedding with a coating ( 34 ), which has a boiling temperature which is lower than a melting temperature of the carrier body ( 3 ) forming material, the web area ( 8th ) is formed by at a melting of the conductor section ( 7 ) around the ladder section ( 7 ) a zone of reduced magnetic permeability is formed. Component ( 2 ) according to one of the preceding claims, wherein on the surface of the web region ( 8th ) a notch ( 6 ) is provided. Electric machine ( 1 ) with a component ( 2 ) according to one of the preceding claims, wherein the component in particular as a rotor of the electric machine ( 1 ) - which is in particular provided as an asynchronous machine - is formed, and the rotor is preferably surrounded by a stator having electrical windings. Method for producing a component ( 2 ) an electric machine ( 1 ), comprising the steps of: - providing a carrier body ( 3 ), in the at least one electrical conductor section ( 7 ) is embedded; Increasing a relative magnetic resistance of one between the conductor section ( 7 ) and a surface (UR, US) of the carrier body (US Pat. 3 ) formed web area ( 8th ). The method of claim 9, wherein increasing the relative reluctance is performed by moving the material of the land region (10). 8th ) is treated so that it becomes at least partially porous or porous. Method according to claim 9 or 10, wherein the increase of the relative magnetic resistance is carried out in that the material of the land area ( 8th ) is treated so that it at least partially austenitic, in particular by melting with the addition of Austenitbildner - preferably as a Einbringmaterial. The method of claim 9 to 11, wherein increasing the relative magnetic resistance by: locally applying a Einbringmaterials on the surface (UR, US) on the support body ( 3 ) near the ladder section ( 7 ) and - subsequent local remelting is achieved. The method of any one of claims 9 to 12, wherein increasing the relative magnetic resistance comprises the steps of: - providing a coating ( 34 ) with a Einbringmaterial, in particular zinc, on the preferably formed with copper or aluminum conductor section ( 7 ), wherein the introduction material has a boiling temperature which is lower than a melting temperature of the material of the carrier body ( 3 ), and - subsequent local melting of the conductor section ( 7 ) having a temperature above the boiling point of the introduction material and below the melting temperature of the material of the carrier body ( 3 ), so that at least in the web area ( 8th ) a zone of reduced magnetic permeability is formed. The method of at least one of the preceding claims 9 to 13, wherein increasing the relative magnetic resistance comprises the steps of: - forming a notch ( 6 ) on the surface of the land area ( 8th ), and - subsequent local fusion welding at the notch ( 6 ).

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