DE102018208410A1 - Short circuit rotor for an electric motor, in particular an asynchronous motor, electric motor, and method for producing a squirrel cage rotor - Google Patents

Abstract

The present invention relates to squirrel-cage rotors (R) for an electric motor, in particular an asynchronous motor, having an axis of rotation (4) comprising at least one first shorting ring (1), an axially spaced second shorting ring (1a), and a shorting bar (2) Shorting bar (2) has a portion (21) with a first cross section (A1) and a terminal body segment (22) with a second cross section (A2), wherein the second cross section (A2) is greater than the first cross section (A1), wherein the Shorting rings (1) have an inner side (11) facing the shorting bar (2), wherein the connecting body segment (22) is connected to the inner side (11) of one of the shorting rings (1 or 1a), an electric motor with a squirrel cage rotor according to the invention, and a Method for producing a squirrel cage rotor according to the invention.

Description

The present invention relates to a squirrel cage rotor for an electric motor, in particular an asynchronous motor, according to the preamble of claim 1, an electric motor according to the preamble of claim 9, and a method for producing a squirrel cage rotor according to the preamble of claim 10 or 11.

Squirrel-cage or squirrel-cage rotors are called rotors of electric motors, in particular asynchronous motors, which instead of a wire wound coil supplied with slip rings have a cage permanently short-circuited in the laminated core (massive turns).

Typically, the squirrel cage rotor includes a first shorting ring and a second shorting ring mounted axially spaced apart on a shaft. At least one short-circuiting rod, preferably a plurality of short-circuiting rods, is arranged between the short-circuiting rings, which preferably run parallel to the shaft and are furthermore preferably arranged next to one another in the circumferential direction. Preferably, the shorting bars are accommodated in laminations. Several laminations result in the so-called laminated core.

In the context of the production of such squirrel cage rotors, the shorting bars must be connected to the shorting rings at least electrically, preferably electrically and mechanically. For this purpose, some methods have become known in the prior art.

In the DE 195 22 671 C2 For example, it describes how shorting bars are passed through the shorting rings and their ends are plastically deformed. Alternatively, it is also proposed here that the ends of the short-circuit bars surround the short-circuit rings.

In the US 5,642,010 A For example, it is proposed that short-circuit bars be used, which are end equipped with short-circuit ring segments, wherein the short-circuit ring completes after insertion of all shorting rods. Alternatively, the short-circuit ring can also be composed of separate short-circuit ring segments.

From the JPH 10-174386 A For example, it has become known to deform the ends of the short-circuiting rods protruding from the laminated core in such a way that they themselves form a short-circuiting ring.

The proposed measures are sometimes problematic in terms of production technology and place special demands on the short-circuit bar material, in particular if electric motors with high power are to be provided. For example, the short-circuit ring according to JPH 10-174386 A not be made arbitrarily thick, since from a certain thickness of the short-circuiting rods such a transformation production technology is no longer feasible.

This is where the present invention is based and makes it its mission to propose an improved squirrel-cage rotor, in particular to propose a squirrel-cage rotor which can be produced reliably and can also be used for high loads.

According to the invention this object is achieved by a squirrel cage with the characterizing features of claim 1. Characterized in that the shorting bar has a portion with a first cross section and a terminal body segment with a second cross section, wherein the second cross section is greater than the first cross section, wherein the shorting rings have an inner side facing the shorting bar, wherein the terminal body segment with the inside of one of the shorting rings connected, can be transmitted through the enlarged surfaces high currents between the shorting ring and the shorting bar. Likewise, the connection between the shorting bar and the shorting ring is displaced to the inside of the shorting ring, so that, for example, no shorting bars have to be bent around the shorting ring, which come to lie, for example, on the outside. As a result, the production is much more reliable process feasible and also the axial space can be reduced by this measure tends.

Further advantageous embodiments of the proposed invention will become apparent in particular from the features of the dependent claims. The objects or features of the various claims can basically be combined with each other arbitrarily.

In an advantageous embodiment of the invention can be provided that the squirrel cage rotor is equipped with at least a first shorting bar and a second shorting bar, the shorting bars are equipped on one side with a terminal body segment, wherein the shorting bars are arranged alternately with respect to the axial orientation of the terminal body segment, wherein the terminal body segment of the first shorting bar is connected to the inside of the first shorting ring, wherein the terminal body segment of the second shorting bar is connected to the inside of the second shorting ring. The short-circuiting rods of a short-circuit rotor configured in this way can be shaped separately and, in particular, outside the laminated core. The reshaping can therefore be individually tailored to the material of the shorting bar.

In a further advantageous embodiment of the invention can be provided that the shorting bar has a second terminal body segment with a third cross section, wherein the third cross section is greater than the first cross section, wherein the first terminal body segment with the inside of the first shorting ring and the second terminal body segment with the Connected inside the second shorting ring. The short-circuit bars of a squirrel cage configured in this way can advantageously be reshaped within the laminated core. Preferably, the first and second connector body segments are similar, so that a symmetrical short-circuiting rod is formed. Symmetrically designed short-circuit rods have the advantage that the current transfer surfaces between the short-circuiting rod and short-circuit ring are of identical design on both sides, so that a homogeneous current flow is ensured.

In a further advantageous embodiment of the invention can be provided that the squirrel-cage rotor is equipped in the circumferential direction with short-circuit bars, wherein in the circumferential direction adjacent terminal body segments form a connection body for the short-circuit ring. The terminal body segments may form a segmented terminal body having an approximately circular shape. If there are gaps between the individual connector body segments, they can be closed by welding, for example. The connection body forms a joining partner for the connection to the respectively assigned short-circuit ring or its inner side. Connection body and short-circuit ring, for example, by welding, friction welding, rotational friction welding, soldering, etc. may be interconnected.

In a further advantageous embodiment of the invention can be provided that the short-circuit ring comprises a joining body and a support body, wherein the joining body forms the inside of the short-circuit ring. By virtue of this hybrid construction, it is possible to assign the individual components to preferred tasks, such as, for example, the mechanical stability or the joining behavior, and to optimize them by means of a corresponding configuration and / or material selection.

For example, it may be provided that the support body consists of aluminum or an aluminum alloy. Although aluminum does not have the electrical conductivity of copper, but is much more stable and therefore is advantageously suitable as a support body, whereby a current-conducting function is not excluded.

Thus, it may further be provided that the joining body and the short-circuiting rods or rods consist of the same material, in particular copper or a copper alloy. The material equality results in advantages in the connection of the aforementioned components. For example, both components have the same melting point, so that these parameters can be taken into account in the connection and results in a correspondingly reliable connection. In addition, there is an advantageous electrical connection.

In a further advantageous embodiment of the invention can be provided that the at least one short-circuiting rod is received in a laminated core. The laminated core can hold the shorting bars in a corresponding position, for example during the forming process. But otherwise, the laminated core holds the short-circuiting rods additionally in a predetermined position.

A further object of the present invention is to provide an improved electric motor, in particular asynchronous motor, with a squirrel-cage rotor, in particular to provide a powerful and compact electric motor.

According to the invention this object is achieved by an electric motor, in particular asynchronous motor, with the characterizing features of claim 9. The advantages of the squirrel cage rotor according to the invention can be made useful for the electric motor.

Another object of the present invention is to propose an advantageous method for producing a short-circuit ring of a squirrel cage rotor according to the invention. According to the invention, this object is achieved by a method according to claim 10 or 11.

• - Umformen von Kurzschlussstabhalbzeugen mit einem ersten Querschnitt in Kurzschlussstäbe mit einem Abschnitt mit dem ersten Querschnitt und ein Anschlusskörpersegment mit einem zweiten Querschnitt, wobei der zweite Querschnitt größer als der erste Querschnitt ausgestaltet ist;
• - Einbringen der Kurzschlussstäbe alternierend im Hinblick auf die axiale Ausrichtung des Anschlusskörpersegmentes in das Blechpaket zwischen den Kurzschlussringen.

A method for producing a squirrel-cage rotor according to claim 2 advantageously has at least the following method steps:

• - Forming short-circuited rod semi-finished products with a first cross-section in short-circuit bars having a portion with the first cross section and a terminal body segment with a second cross section, wherein the second Cross section is designed larger than the first cross section;
• - Inserting the short-circuit bars alternately with regard to the axial alignment of the connector body segment in the laminated core between the short-circuiting rings.

Due to the alternating orientation of the short-circuit bars, the short-circuit bar semi-finished products can be reshaped outside the laminated core. A burden of the laminated core by the deformation of the short-circuit bar semi-finished products can be avoided.

• - Einbringen von Kurzschlussstabhalbzeugen mit jeweils einem ersten Querschnitt in das Blechpaket;
• - Umformen der Kurzschlussstabhalbzeuge in Kurzschlussstäbe mit jeweils einem Abschnitt mit dem ersten Querschnitt, einem ersten Anschlusskörpersegment mit einem zweiten Querschnitt und einem zweiten Anschlusskörpersegment mit einem dritten Querschnitt, wobei sowohl der zweite Querschnitt, als auch der dritte Querschnitt größer als der erste Querschnitt ausgestaltet sind.

A method for producing a squirrel-cage rotor according to claim 3, with a laminated core for receiving short-circuit bars between the short-circuited rings, preferably has at least the following method steps:

• - Introduction of Kurzschlussstabhalbzeugen each with a first cross section in the laminated core;
• - Forming the Kurzschlussstabhalbzeuge in shorting bars, each having a portion of the first cross section, a first connector body segment having a second cross section and a second connector body segment having a third cross section, wherein both the second cross section and the third cross section are larger than the first cross section.

The introduction of the short-circuit bar semi-finished products in the laminated core takes place before forming. Accordingly, the deformation can be made within the laminated core.

Further advantageous embodiments of the proposed invention will become apparent in particular from the features of the dependent claims. The features of the various claims can basically be combined with each other arbitrarily.

In an advantageous embodiment of the invention can be provided that the deformation of the Kurzschlussstab semi-finished product is made by pressing, tumbling and / or bending.

In a further advantageous embodiment of the invention can be provided that the Kurzschlussstab semi-finished is sharpened before forming. In this way it can be achieved that as much material as possible is brought inwards in the direction of the axis of rotation, whereby the concentricity properties of the squirrel-cage rotor can be improved.

In a further advantageous embodiment of the invention can be provided that the circumferentially juxtaposed connector body segments are joined together to form a connector body, wherein the respective connector body is connected to the inside of each short-circuit ring, in particular by means of welding, preferably by means of rotary friction welding.

In a further advantageous embodiment of the invention can be provided that prior to the connection of the connector body with the inside of the respective shorting ring of the connecting body and / or the inside of the connecting ring with annular projections and / or annular grooves are provided or equipped with annular grooves and / or annular projections Connection body and / or inside of the connection ring can be used. This is a preferred embodiment, in particular for aluminum short-circuit rings. In rotary friction welding, the short-circuit ring is softened. The copper shorting bars do not soften because of higher melting temperature or at least hardly. Therefore, the ring protrusions dig into the soft aluminum.

• 1 einen erfindungsgemäßen Elektromotor in einer geschnittenen Darstellung;
• 2 einen erfindungsgemäßen Kurzschlussläufer in einer Explosionsdarstellung;
• 3 einen Kurzschlussstab mit einem einseitig vorgesehenen Anschlusskörpersegment;
• 3a einen Schnitt X-X gemäß 3;
• 3b einen Schnitt Y-Y gemäß 3;
• 4 einen Kurzschlussstab mit beidseitig vorgesehenen Anschlusskörpersegmenten;
• 4a einen Schnitt X-X gemäß 4;
• 4b einen Schnitt Y-Y gemäß 4;
• 4c einen Schnitt Z-Z gemäß 4;
• 5 Umformen eines Kurzschlussstabhalbzeuges durch Pressen;
• 5a ein Schnitt X-X gemäß 5;
• 6 Umformen eines Kurzschlussstabhalbzeuges durch Biegen und Pressen;
• 6a einen Schnitt X-X gemäß 6;
• 7a schematische Darstellung einer alternierenden Anordnung von Kurzschlussstäben (ohne Darstellung der Blechlamellen / Blechpaket);
• 7a' eine Draufsicht auf ein Blechpaket mit alternierend eingesteckten Kurzschlussstäben (T-förmig);
• 7b Rotationsreibschweißen von Kurzschlussringen und Anschlusskörper;
• 7b' Rotationsreibschweißen von Kurzschlussringen und Anschlusskörper;
• 7c Verbund aus Kurzschlussstäben und Kurzschlussringen;
• 8a schematische Darstellung einer alternierenden Anordnung von Kurzschlussstäben (ohne Darstellung der Blechlamellen / Blechpaket;
• 8a' eine Draufsicht auf ein Blechpaket mit alternierend eingesteckten Kurzschlussstäben (L-förmig);
• 8b Lückenschluss durch Verschweißen;
• 8c Rotationsreibschweißen von Kurzschlussringen und Anschlusskörper;
• 8d Verbund aus Kurzschlussstäben und Kurzschlussringen;
• 9a eine Draufsicht und eine teilweise geschnittene Ansicht auf ein Blechpaket mit eingesteckten Kurzschlussstabhalbzeugen;
• 9b ein Presswerkzeug, welches die Kurzschlussstabhalbzeuge in dem Blechpaket umformt;
• 9c eine Draufsicht und eine teilweise geschnittene Ansicht auf ein Blechpaket mit umgeformten Kurzschlussstabhalbzeugen;
• 10a ein großes Taumelpresswerkzeug, welches die Kurzschlussstabhalbzeuge in dem Blechpaket umformt;
• 10b ein kleines Taumelwerkzeug, welches die Kurzschlussstabhalbzeuge in dem Blechpaket einzeln umformt;
• 10c eine Draufsicht auf ein Blechpaket mit umgeformten Kurzschlussstabhalbzeugen;
• 10d eine Draufsicht auf ein Blechpaket mit umgeformten Kurzschlussstabhalbzeugen, mit einem abgedrehten Anschlusskörper;
• 11a, b, c alternative Enden von Kurzschlussstabhalbzeugen;
• 12a-d Umformung von Kurzschlussstabhalbzeugen mittels eines zweistufigen Pressprozesses;
• 13a-d Umformung von Kurzschlussstabhalbzeugen mittels eines zweistufigen Press- und Taumelprozesses;
• 14a-b alternative Oberflächenstrukturen von Kurzschlussring und/oder Anschlusskörper;
• 15a eine Draufsicht auf ein Blechpaket mit umgeformten Kurzschlussstabhalbzeugen;
• 15b eine Draufsicht auf ein Blechpaket mit abgedrehten Kurzschlussstabhalbzeugen;
• 16 einen hybriden Kurzschlussring.

Further features and advantages of the present invention will become apparent from the following description of preferred embodiments with reference to the accompanying schematic drawings. Show in it

• 1 an electric motor according to the invention in a sectional view;
• 2 a squirrel cage rotor according to the invention in an exploded view;
• 3 a shorting bar with a unilaterally provided terminal body segment;
• 3a a cut XX according to 3 ;
• 3b a cut YY according to 3 ;
• 4 a short-circuiting rod with connector body segments provided on both sides;
• 4a a cut XX according to 4 ;
• 4b a cut YY according to 4 ;
• 4c a cut ZZ according to 4 ;
• 5 Forming a short-cut bar semi-finished product by pressing;
• 5a a cut XX according to 5 ;
• 6 Forming a short-cut bar semi-finished product by bending and pressing;
• 6a a cut XX according to 6 ;
• 7a schematic representation of an alternating arrangement of short-circuit bars (without showing the laminations / laminated core);
• 7a ' a top view of a laminated core with alternately inserted short-circuiting rods ( T -shaped);
• 7b Rotational friction welding of short-circuited rings and connection body;
• 7b ' Rotational friction welding of short-circuited rings and connection body;
• 7c Composite of short-circuit bars and short-circuit rings;
• 8a schematic representation of an alternating arrangement of short-circuit bars (without representation of the lamination / laminated core;
• 8a ' a top view of a laminated core with alternately inserted short-circuiting rods ( L -shaped);
• 8b Gap closure by welding;
• 8c Rotational friction welding of short-circuited rings and connection body;
• 8d Composite of short-circuit bars and short-circuit rings;
• 9a a plan view and a partially sectioned view of a laminated core with inserted Kurzschlussstabhalbzeugen;
• 9b a pressing tool, which transforms the short-circuit bar semi-finished products in the laminated core;
• 9c a plan view and a partially sectioned view of a laminated core with deformed Kurzschlussstabhalbzeugen;
• 10a a large tumbling press tool, which transforms the short-circuit bar semi-finished products in the laminated core;
• 10b a small tumbling tool, which individually transforms the short-circuit bar semi-finished products in the laminated core;
• 10c a plan view of a laminated core with deformed Kurzschlussstabhalbzeugen;
• 10d a plan view of a laminated core with formed Kurzschlussstabhalbzeugen, with a turned-off connector body;
• 11a, b . c alternative ends of shorting bar semi-finished products;
• 12a-d Forming short-circuited semi-finished products by means of a two-stage pressing process;
• 13a-d Forming short-circuited semi-finished products by means of a two-stage pressing and tumbling process;
• 14a-b alternative surface structures of short-circuit ring and / or connection body;
• 15a a plan view of a laminated core with deformed Kurzschlussstabhalbzeugen;
• 15b a plan view of a laminated core with twisted Kurzschlussstabhalbzeugen;
• 16 a hybrid short-circuit ring.

First, it will open 1 Referenced.

An inventive electric motor, in particular asynchronous motor, essentially comprises a stator S and a rotor R in the form of a squirrel cage rotor according to the invention.

A squirrel cage rotor according to the invention R essentially comprises a first short-circuit ring 1 and preferably a further, second shorting ring 1a on a wave 4 axially spaced from each other are mounted. Between the shorting rings 1 . 1a is at least one shorting bar 2 , preferably a plurality of shorting bars 2 . 2a . 2 B , ..., which are preferably parallel to the shaft 4 extend and are further preferably mounted adjacent to each other in the circumferential direction. Preferably, the shorting bars are in laminations 3 added. Several laminations result in the so-called laminated core.

According to the invention, it is provided that the at least one short-circuiting rod has a section 21 with a first cross section A1 and a terminal body segment 22 with a second cross section A2 forms, wherein the second cross section A2 larger than the first cross section A1 is, wherein the at least one short-circuit ring 1 an inner side facing the at least one shorting bar 11 having, wherein the short-circuit ring 1 on its inside 11 with the connector body segment 22 of the short-circuiting rod 2 connected is.

Further preferably, it can be provided that the at least one short-circuiting rod 2 a second connector body segment 23 with a third cross section A3 forms, wherein the third cross section A3 larger than the first cross section A1 is, wherein the second shorting ring 1a on its inside 11 with the second terminal body segment 23 of the short-circuiting rod 2 connected is.

At the shorting bar 2 it is an elongated rod-shaped body, preferably made of copper or a copper alloy. The shorting bar 2 has a longitudinal axis L on. Transverse to this longitudinal axis L run the above-mentioned cross sections A or cross-sectional areas. The first connector body segment 22 with the second cross section A2 is from the first end face and the second terminal body segment 23 with the third cross section A3 is, if provided, from the second end of the shorting bar 2 educated. The first cross section A1 is formed by a cross section, which, for example, on half the length of the shorting bar 2 located. The first connector body segment 22 and the second terminal body segment 23 For example, by a T- or L-shaped end of the shorting bar 2 be formed. For the sake of simplicity, it will be referred to hereinafter as a T-shape and an L-shape. The shorting bar 2 is preferably designed in one piece.

Further details of the proposed invention emerge in particular from the manufacturing process.

The production of the shorting bar 2 as such is preferably made of a semi-finished product H which preferably over the entire longitudinal axis L the first cross section A1 having. By massive forming, such as bending and / or pressing, the terminal body segment 22 or become the terminal body segments 22 . 23 produced. For example, the L-shape becomes by bending the one or more ends of the short-cut bar semi-finished product H and the T-shape by bending and pressing the ends of the short-cut bar semi-finished product H produced. In the two-stage manufacturing process (bending and pressing), the degrees of deformation are usually smaller than in single-stage (bending).

With regard to the processing location or time of the short-circuit bar semi-finished product basically two variants are conceivable.

In a first variant, the at least one short-circuiting bar 2 or are the shorting bars 2 . 2a . 2 B . 2c , ... before insertion into the laminations or the laminated core 3 from a short-cut bar semi-finished product H reshaped. In this variant, the material can be heated for easier forming (hot deformation), without having to take into account, for example, a heat-sensitive insulation of a laminated core.

Shorting bars 2 . 2a . 2 B . 2c , ... for this production variant have only one side of a connector body segment 22 on.

Inserting the shorting bars 2 . 2a . 2 B . 2c , ... takes place alternately, ie shorting bars are in alternating axial alignment with respect to the terminal body segment 22 in the laminated core 3 inserted. This preferably takes place in such a way that the end faces of the short-circuiting rods without a formed connecting-body segment terminate flush with the connecting-body segments not only in the circumferential direction but also in the axial height. Based on, for example, two shorting bars 2 . 2a this means that the connector body segment 22 the first shorting bar 2 with the inside 11 of the first short-circuit ring 1 is connected, wherein the terminal body segment 22 of the second shorting bar 2a with the inside 11 of the second short-circuit ring 1a connected is. Accordingly, the respective other ends of the short-circuit bars 2 respectively. 2a without connection body segment with the other short-circuit ring 1a respectively. 1 connected.

Preferably, the terminal body segment 22 configured such that the terminal body segments together with protruding sections 21 with first cross-section A1 in the circumferential direction touching each other and a gap closure is realized. A possibly missing gap closure can be closed by welding. As a result, the terminal body segments form 22 a preferably closed in the circumferential direction circular connection body K ,

In a further variant, it can be provided that the deformation of the short-circuit bar or the deformation of the short-circuit bars 2 . 2a . 2 B . 2c , ... from short-circuited semi-finished products H after insertion into the laminations 3 or the laminated core is made. The reshaping thus takes place to some extent already used in the laminated core Kurzschlussstabhalbzeugen.

• - Axiales Pressen der Kurzschlussstäbe, alle miteinander auf einmal
• - Axiales Pressen der Kurzschlussstäbe, abschnittsweise
• - Taumeln aller Kurzschlussstäbe auf einmal, insbesondere mit einem großen Taumelwerkzeug
• - Taumeln jedes Kurzschlussstabes einzeln und nacheinander, insbesondere mit einem kleinen Taumelwerkzeug
• - Umbiegen der Kurzschlussstäbe mit oder ohne Überlappungsanteile

For such a transformation, in particular the following approaches are possible:

• - Axial pressing of the shorting bars, all together at once
• - Axial pressing of the shorting bars, in sections
• - Tumble all shorting bars at once, especially with a large wobble tool
• - Tumble each shorting bar individually and sequentially, especially with a small wobble tool
• - Bending the shorting bars with or without overlapping shares

The procedure can basically be combined with each other as desired. The corresponding tools are shown in the figures with the reference number pressing tool P or wobble tool T Provided.

The deformation preferably takes place at both ends of the short-cut rod semi-finished product H instead, so that per Kurzschlussstabhalbzeug two terminal body segments 22 . 23 at both ends of the shorting bar. The design of the terminal body segments can, as already above L- or T-shaped, depending on which forming process is preferred.

The connection body segments 22 respectively. 23 One side are preferably designed such that they touch each other in the circumferential direction and a gap closure is realized. A possibly missing gap closure can be closed, for example, by welding. As a result, the terminal body segments form 22 respectively. 23 a preferably closed in the circumferential direction circular connection body K ,

Subsequently, in both cases (forming inside or outside the laminated core), a connection, in particular an electrical and mechanical connection, between the inside 11 of the respective short-circuit ring 1 respectively. 1a and the respective connection body 22 respectively. 23 the shorting bars 2 . 2a . 2 B . 2c , ... produced. At the same time, if present, the ends of the short-circuiting rods without connection body with the respective shorting rings 1 respectively. 1a connected. The connection is preferably produced by welding, in particular by rotary friction welding. The insides 11 the shorting rings 1 . 1a are accordingly also facing each other.

Preferably, the inside becomes 11 of the short-circuit ring 1 respectively. 1a from a similar, in particular identical, material such as the short-circuit bar or the enlarged cross-sectional area A2 respectively. A3 formed of the shorting bar, in particular of copper or a copper alloy. Here can be a hybrid shorting ring 1 respectively. 1a are used, comprising a joining body 11 and a support body 12 , Here, the joining body forms 11 the inside of the short-circuit ring. Preferably, the joining body 11 or the inside of the shorting ring made of the same material as the shorting bars 2 . 2a . 2 B . 2c , ... or their terminal body segments 22 respectively. 23 , in particular of copper or a copper alloy. The supporting body 12 may be made of another material, such as aluminum or an aluminum alloy.

The short-circuit ring 1 can also with a diffusion barrier between joining body 11 and supporting body 12 be equipped. This is intended to prevent or at least reduce the build-up of a boundary layer or intermediate layer of aluminum or copper oxides as well as the diffusion of atoms of one material into the crystal lattice of the other material. Preferably, not only one joining partner is provided with a diffusion barrier before joining, but both. Preferred material of the diffusion barrier is eg nickel or silver.

Such a trained short-circuit ring 1 . 1a has advantages. In particular, there is the material equality between joining body 11 and connection body K a favorable electrical connection. However, due to the material equality, there are also mechanical advantages, in particular since material-identical joining partners can be optimally fitted. The mechanical stability of the short-circuit ring can be provided mainly by the support body.

Further aspects of the present invention emerge in particular from the to ,

In the 11 is a short-circuit bar semi-finished product H shown with non-straight ends, in particular oblique ends, partially oblique ends and combined oblique ends (asymmetric dovetail shape). The molds primarily serve to influence the flow behavior during forming. Preferably, the material during the forming inward, in the direction of the axis of rotation 4 flow.

In the 12 is shown a forming process in the form of a two-stage pressing process. A first pressing tool first forms the ends of the short-circuited semi-finished products as tips, for example with a partially oblique end. By reshaping as much material as possible should first be brought inside. A second pressing tool re-forms the ends to the terminal body segment.

In the 13 is a forming process in the form of a two-stage pressing and tumbling process shown. A pressing tool first of all shapes the ends of the short-circuiting semi-finished products into a shape that is approximately ax-shaped in cross-section. By reshaping as much material as possible should first be brought inside. A wobble tool shapes the ends to the connector body segment.

In the 14a are one with ring grooves 5 provided connecting body and one with complementary annular projections 6 equipped short-circuit ring 1 shown. In the 14b are shown provided with annular projections connector body and a flat short-circuit ring. This is a preferred embodiment, in particular for aluminum short-circuit rings. In rotary friction welding, the short-circuit ring is softened. The copper shorting bars do not soften because of higher melting temperature or at least hardly. Therefore, the ring protrusions dig 6 into the soft aluminum.

In the 15a is a plan view of a laminated core with deformed Kurzschlussstabhalbzeugen shown. In particular, it is connector body segments that are made by bending.

In the 15b is a plan view of a laminated core with deformed Kurzschlussstabhalbzeugen according to 15a shown, whose terminal body segments have been turned off. As a result, a planar joining surface can be made available for a subsequent connection process with a short-circuit ring.

Of course, features and details described in connection with the method also apply in connection with the device according to the invention and vice versa, so that reciprocal reference to the individual aspects of the invention is or can always be made. In addition, the inventive method can be carried out with the device according to the invention.

LIST OF REFERENCE NUMBERS

R

Squirrel cage rotor

S

stator

L

longitudinal axis

A1

first cross-section

A2

second cross section

A3

third cross section

H

semis

K

connection body

P

press tool

T

Tumbling (press) tool

1

Shorting ring

2

Shorting bar

3

Sheet metal lamination / laminated core

4

Shaft / rotation axis

5

ring groove

6

annular projection

11

Inside / joining body

12

support body

21

section

22

(first) terminal body segment

23

second connection body segment

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 19522671 C2 [0005]
• US 5642010 A [0006]
• JP H10174386A [0007, 0008]

Claims (15)

Squirrel cage rotor (R) for an electric motor, in particular an asynchronous motor, having an axis of rotation (4), comprising at least - a first shorting ring (1), an axially spaced second shorting ring (1a), and - a shorting bar (2), characterized in that - The shorting bar (2) has a portion (21) having a first cross section (A1) and a terminal body segment (22) having a second cross section (A2), wherein - the second cross section (A2) is greater than the first cross section (A1) in which - the short-circuit rings (1) have an inner side (11) facing the short-circuiting rod (2), wherein - the connecting-body segment (22) is connected to the inner side (11) of one of the short-circuiting rings (1 or 1a). Squirrel cage after Claim 1 , characterized in that the squirrel cage rotor is equipped with at least one first shorting bar (2) and one second shorting bar (2a), wherein - the shorting bars (2, 2a) are equipped on one side with a terminal body segment (22), wherein - the shorting bars (2 , 2a, 2b, ...) are arranged alternately with respect to the axial orientation of the connector body segment (22), wherein - the connector body segment (22) of the first shorting bar (2) with the inside (11) of the first short-circuit ring (1) is, wherein - the terminal body segment (22) of the second shorting bar (2a) with the inside (11) of the second shorting ring (1a) is connected. Squirrel cage after Claim 1 characterized in that - the shorting bar (2) has a second terminal body segment (23) with a third cross section (A3), wherein - the third cross section (A3) is larger than the first cross section (A1), wherein - the first terminal body segment ( 22) is connected to the inner side (11) of the first short-circuit ring (1) and - the second terminal body segment (23) is connected to the inner side (11) of the second short-circuit ring (1a). A squirrel-cage rotor according to at least one of the preceding claims, characterized in that the squirrel-cage rotor is equipped with short-circuit bars (2, 2a, 2b, ...) in the circumferential direction, connecting body segments (22 or 23) arranged next to one another in the circumferential direction having a connection body (K) for form the short-circuit ring (1 or 1a). Squirrel-cage rotor according to at least one of the preceding claims, characterized in that the short-circuit ring (1) comprises a joining body (11) and a supporting body (12), wherein the joining body (11) forms the inside of the short-circuit ring (1). A squirrel-cage rotor according to at least one of the preceding claims, characterized in that the supporting body (12) consists of aluminum or an aluminum alloy. A squirrel-cage rotor according to at least one of the preceding claims, characterized in that the joining body (11) and the shorting bar (s) consist of the same material, in particular copper or a copper alloy. Squirrel-cage rotor according to at least one of the preceding claims, characterized in that the at least one short-circuiting rod (2, 2a, 2b, ...) is accommodated in a laminated core (3). Electric motor, in particular an asynchronous motor, comprising a stator (S) and a squirrel cage rotor (R) designed as a rotor, characterized by a squirrel cage rotor (R) according to at least one of the preceding claims. Method for producing a squirrel cage according to Claim 2 , with a laminated core (3) for receiving short-circuit bars (2, 2a, 2b,...) between the short-circuit rings (1, 1a), characterized by at least the following method steps: - forming short-circuited semi-finished products (H) with a first cross-section (A1 ) in shorting bars (2, 2a, 2b,...) with a section (21) having the first cross section (A1) and a terminal body segment (22) having a second cross section (A2), wherein the second cross section (A2) is greater than the first cross section (A1) is configured; - introducing the shorting bars (2, 2a, 2b, ...) alternately with regard to the axial alignment of the terminal body segment (22) in the laminated core between the short circuit rings (1, 1a). Method for producing a squirrel cage according to Claim 3 , with a laminated core (3) for receiving short-circuit bars (2, 2a, 2b,...) between the short-circuit rings (1, 1a), characterized by at least the following method steps: - introducing short-circuited semi-finished products (H) each having a first cross-section ( A1) in the laminated core (3); - Forming the Kurzschlussstabhalbzeuge in shorting bars (2, 2a, 2b, ...), each having a portion (21) with the first cross section (A1), a first terminal body segment (22) with a second cross section (A2) and a second terminal body segment (23) having a third cross section (A3), wherein both the second cross section (A2), and the third cross section (A3) are larger than the first cross section (A1). Method according to at least one of the preceding claims, characterized in that the forming of the short-cut bar semi-finished product (H) by pressing, tumbling and / or bending is carried out. Method according to at least one of the preceding claims, characterized in that the head end of the short-cut rod semi-finished product (H) before forming a non-planar end face, in particular a projecting inwardly or outwardly pointed or conical and / or convex shape. Method according to at least one of the preceding claims, characterized in that the connection body segments (22 or 23) arranged adjacent to one another in the circumferential direction are joined together to form a connection body (K), the respective connection body (K) being connected to the inner side (11) of the respective short-circuit ring ( 1 or 1a) is connected, in particular by means of welding, preferably by means of rotary friction welding. Method according to at least one of the preceding claims, characterized in that prior to the connection of the connecting body (K) with the inner side (11) of the respective short-circuit ring (1 or 1a), the connecting body (K) and / or the inner side (11) of the connecting ring (1) with annular projections (6) and / or annular grooves (5) are provided or equipped with annular grooves and / or annular projections connecting body (K) and / or inside (11) of the connecting ring (1) are used.

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