DE102016217516A1 - An electric rotor and method for providing electrical contact between a rotor winding and a contact lug - Google Patents

Abstract

The invention relates to an electric rotor (10), comprising a rotor winding (14) with an electrical conductor (24) made of a first electrically conductive material; a contact lug (16) of a slip ring assembly (12), the contact lug (16) being made of a second electrically conductive material different from the first electrical material; a contactor (26) adapted to make electrical contact between the electrical conductor (24) of the rotor winding (14) and the contact lug (16); wherein the contacting element (26) is designed to make electrical contact with the electrical conductor (24) of the rotor winding (14) via a first contact surface (26b) and makes electrical contact with the contact lug (16) via a second contact surface (26c). wherein the contacting element (26) comprises, at least at the first contact surface (26b), a third electrically conductive material different from the first electrical material.

Description

The present invention relates to an electric rotor and a method for providing an electrical contact between a rotor winding and a contact lug of the rotor. The invention thus finds particular application in the field of electric motors and three-phase generators, in particular in a motor vehicle.

State of the art

Electric rotors are used in power generators, such as in three-phase generators, or in electric motors. So-called. In this case, separately excited rotors each have at least one rotor-energizing winding, which is electrically connected to a slip-ring arrangement for energizing. Conventionally, both the electrical winding of the rotor, i. the rotor winding, as well as the slip ring assembly and the commutator formed of copper. These can be electrically contacted with each other in an efficient manner, for example by soldering, resistance welding and / or ultrasonic welding.

For example, in the document DE 38 38 436 A1 discloses a conventional three-phase generator in which the rotor field winding and the connecting lines are electrically contacted by spot welding.

However, for cost reasons, it is often desirable not to use wires of copper as the winding wires for the rotor winding, but wires of less expensive metals, such as aluminum. In order to then connect these with the other components, such as the slip ring assembly made of copper, complex procedures are often necessary to protect the contact point between copper and other metals, such as aluminum, from corrosion. This often requires a considerable production effort and thus increases the production costs. In the prior art, various approaches are known to still produce a suitable connection between copper and aluminum wires.

The publication US 2,806,215 A discloses, for example, a compression sleeve of aluminum, which is adapted to be pressed against a stripped end of an aluminum wire, wherein for connecting the aluminum wire or the compression sleeve with a copper wire to the compression sleeve, a ring section made of copper is welded.

The publication DE 10 2013 200 794 A1 discloses a contactor for providing electrical contact to an electrical machine. In this case, the contacting of a multi-component compound of two different conductive materials is formed to connect a winding assembly of a material different from the commutator material compatible with the commutator hook. The contacting element has a first connecting section of the same material as the winding arrangement for connection to the winding arrangement and a second connecting section of the same material as the commutator hook for connection to the commutator hook.

Disclosure of the invention

According to the invention, an electric rotor and a method for providing an electrical contact between an electrical conductor of a rotor winding and a contact lug of a slip ring assembly having the features of the independent claims are proposed. Advantageous embodiments are the subject of the dependent claims and the following description.

It is proposed in the context of the invention to connect the electrical conductor comprising a first electrically conductive material, in particular aluminum, to the contact lug of a second electrically conductive material, in particular copper, which is different from the first electrical material, by means of a contacting element arranged therebetween at least at the contact surface to the electrical conductor having a different from the first electrical material third electrically conductive material, in particular tin, so as to prevent corrosion by contact of the first with the second material.

The invention offers the advantage that in a simple manner electrical conductors made of different metals can be contacted with each other electrically. This makes it possible in particular to connect a rotor winding of an aluminum generator with a slip ring assembly made of copper protected against corrosion.

By the proposed invention, the rotor winding can be electrically contacted by means of a so-called "cold" contact with the contact lug of the slip ring assembly. This means that in particular no welding and / or soldering of different materials or metals for electrical contacting is required at least at one contact surface. In particular, it is not necessary to melt one or both of the electrical conductors, ie the end of the rotor winding and / or the contact lug, in order to connect to the respective other electrical conductor. On In this way, an excessive susceptibility to corrosion of the contact point can be avoided, which often occurs in a multi-compound compound or intermetallic phase produced primarily by welding and / or soldering. Also, a significant increase in the specific resistance of multi-component compounds, which often leads to a reduction of the conductivity of a contact point in the areas of the multi-substance compounds, can be avoided in an efficient manner with the present invention. Thus, the present invention is particularly well-suited for providing electrical contact between a copper tab and an aluminum electrical conductor.

Instead of a multi-component compound in the contact region, mechanical contacting of the electrical conductor of the rotor winding and of the contact lug can be achieved by the present invention without the electric conductor and / or the contact lug having to be melted for this purpose.

In this case, a further metal layer, in particular a tin layer, is formed as an intermediate layer on the first contact surface, which preferably has a relief-like structuring. This can serve to avoid a direct contact between the first electrically conductive material of the contacting element and the rotor winding and nevertheless produce an electrical contact by means of the intermediate layer. For example, this can be advantageous in the case of electrical contacting between a copper contacting element and an electrical conductor of the aluminum rotor winding in order to prevent corrosion.

Furthermore, the invention makes it possible to considerably simplify the electrical contacting of the rotor winding with the contact lug, since mechanical means for producing a contact between different metals, such as between copper and aluminum, may be sufficient when using a contact element according to the invention. In particular, the invention can cause electrically conductive elements made of different metals, such as copper and aluminum, do not have to be welded and thus no special measures to protect against corrosion are required.

The invention provides the ability to easily contact aluminum rotor windings with conventional copper slip ring assemblies. Thus, conventional electric machines can be equipped with a rotor having a rotor coil made of aluminum and yet contacted with conventional slip ring assemblies made of copper.

Preferably, the contacting element is designed to at least partially receive and at least partially surround the electrical conductor of the rotor winding, in particular its end, wherein the first contact surface, in particular the inner surface, of the contacting element forms an internal receiving surface facing the received first electrical conductor, and preferably has a relief-like structuring, which is adapted to at least partially penetrate into the electrical conductor. In other words, the contacting element is designed in such a way that the relief-like structuring cuts into or crinkles into the electrical conductor of the rotor winding.

In this case, the contacting element is preferably produced in one piece from an electrically conductive material, in particular from a metal. For example, the contacting element may be made of a casting or be punched and / or milled from a piece of metal. For this purpose, a variety of electrical materials, in particular metals, are suitable. Both pure elemental metals and alloys come into consideration. In particular, the material of the contacting element can be chosen such that the contacting element is formed of the same material as the contact lug or the slip ring arrangement which is to be connected to the second contact surface of the contacting element. This can in particular make it possible to carry out the electrically conductive connection or contacting of the contact lug with the contacting element in a particularly simple and familiar manner. For example, this electrical contacting can then also be carried out by means of welding and / or soldering, since no occurrence of a corrosion-prone multi-substance compound of different metals is to be feared during welding and / or soldering. Notwithstanding this, however, the contacting element may also have on the second contact surface a coating which may be beneficial in the production of the electrical contact, for example of tin.

In particular, the second contact surface may be at least partially provided with a further material, in particular with a metal, in particular coated. For example, metals with a low melting point may be advantageous in order to simplify welding and / or soldering to the second contact surface. For example, the second contact surface of the contacting element may be provided at least partially with tin. This has the advantage that the contacting can be well welded to the contact lug and / or soldered.

The relief-like structuring on the first contact surface of the contacting element is thereby preferably formed as a toothing and / or Serration or has such. In particular, the relief-like structuring is designed in such a way that it can at least partially penetrate or squeeze into the conductor when the contacting element is pressed into a conductor located in the contacting element. The relief depth, that is to say the length of the elevations of the structuring of the first contact surface, is preferably designed such that it can penetrate at least in places also insulations and / or lacquer coatings possibly formed on the first electrical conductor and, moreover, at least in places into the electrically conductive part or Core of the electrical conductor of the rotor winding can penetrate. For example, it is advantageous to form the relief depth greater than the thickness of an insulating or lacquer layer of the electrical conductor. Preferably, the relief depth of at least 1 mm, preferably at least 2 mm, more preferably at least 3 mm, even more preferably at least 4 mm, most preferably at least 5 mm.

According to a preferred embodiment, an electric rotor is thus provided with a contacting element coated on at least one contact surface in order to connect a rotor winding made of aluminum to a contact lug made of copper. As a result, a cold contact point without direct aluminum-copper contact can be provided between the contacting element and the rotor winding at the first contact surface, while the second contact surface of the contacting element can be soldered or welded to the contact lug of the slip ring arrangement as conventionally.

Further advantages and embodiments of the invention will become apparent from the description and the accompanying drawings.

The invention is schematically illustrated by means of an embodiment in the drawings and will be described below with reference to the drawings.

Brief description of the drawings

1 shows a schematic longitudinal sectional view of a conventional contacting a conventional rotor with a slip ring assembly;

2 shows a schematic longitudinal sectional view of a contacting of a rotor according to the invention by means of a contacting element;

3 shows a schematic representation of an open contacting element according to a preferred embodiment;

4 shows a schematic representation of a closed contacting element according to a preferred embodiment;

5 shows a profile view of the relief-like structuring of an open contacting element according to a preferred embodiment.

Embodiments of the invention

1 shows a schematic longitudinal sectional view of a conventional contact of a conventional rotor 10 a generator with a slip ring assembly 12 or slip ring assembly. The rotor 10 points as a rotor winding 14 a copper wire with a surrounding paint insulation 14a on and is designed as a copper enamel wire. According to the conventional embodiment, there is one end 14b of the copper wire or the rotor winding 14 stripped and extends into a welding area 16a a contact flag 16 , The contact flag 16 is also designed as copper and in the welding area 16a tinned to weld the stripped end 14b of the copper wire 14 with the contact flag 16 in the welding area 16a to facilitate or facilitate. For example, this can be done by resistance welding and / or ultrasonic welding.

The contact flag 16 is with a wave 18 connected and performs the electrical connection of the rotor winding 14 under a ball bearing 20 and under a slinger 22 therethrough. Beyond the ball bearing 20 and the slinger 22 is the contact flag 16 with the slip ring assembly 12 connected or contacted. The two ends 14b the rotor winding 14 are each separately by means of a contact lug 16 each with a separate slip ring 12a contacted. The contact flag 16 is in a molding compound 28 embedded in insulating material.

According to the conventional embodiment shown, since all of the electrical conductors and conductive components are formed of copper, they can be welded together in a conventional manner without causing an increased degree of susceptibility to corrosion.

2 shows a schematic fragmentary longitudinal sectional view of a contacting of a rotor according to the invention 10 according to a preferred embodiment with a slip ring assembly 12 by means of a contact element 26 , This is a rotor winding 24 from an aluminum wire as the first electrically conductive material with surrounding insulation 24a formed as aluminum enamel wire. The rotor winding 24 is by means of a contacting element according to the invention 26 according to a preferred embodiment with a contact lug 16 made of copper as a second electrically conductive material. The contacting element 26 has a Kontaktierelementkörper 26a made of copper, which has one end of the rotor winding 24 encloses. The contacting element 26 is coated on a first contact surface with the aluminum enameled wire with tin as the third electrically conductive material.

The connection between the contacting takes place 26 and the end of the rotor winding 24 as a "cold" contact by mechanical pressing or crushing on the inside as a first contact surface, while a preferably also tinned outside of the contacting 26 as a second contact surface with a preferably also tin-plated welding area 16a the contact flag 16 is welded.

In this way, a cold contact point is made between aluminum and tin-plated copper without direct aluminum-copper contact, while between copper and copper on conventional connection methods, such as welding and / or soldering can be used. Stripping the end of the rotor winding 24 is when using the contact element 26 not required, since the contacting element according to the embodiment shown, the insulating layer surrounding the aluminum wire 24a at least in places can penetrate.

3 shows a schematic representation of an open contacting element 26 according to a preferred embodiment, which is designed in the manner of a crimp. The contacting element 26 is made of copper and coated with tin. The rotor winding 24 made of aluminum can in the contact element 26 be introduced as the first electrical conductor such that the first contact surface 26b of the contacting element 26 the rotor winding 24 is facing. The relief-like structuring 30 is not visible in the schematic diagram shown (see 5 ).

4 shows the contact element 26 out 3 in a closed state, ie after having been squeezed by a suitable tool. Then encloses the contact element 26 the rotor winding 24 and makes electrical contact between the electrically conductive copper-formed contacting element via the tin-coated first contact surface 26 and within the insulation 24a embedded aluminum wire of the rotor winding 24 ago.

5 shows an exemplary sectional view of a relief-like structuring 30 at the first contact surface of the Kontaktierelementkörpers 26a or Kontaktierelelements 26 according to a preferred embodiment. In this case, in particular, the toothed configuration can be seen, which is a penetration through an optionally existing insulating layer 24a allows for the first electrical conductor and penetration into the first electrical conductor. For example, in particular for differently configured first electrical conductor or for conductors with different insulation and other relief-like structuring 30 be formed, for example, with larger or smaller teeth.

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 3838436 A1 [0003]
• US Pat. No. 2,862,115 A [0005]
• DE 102013200794 A1 [0006]

Claims (11)

Electric rotor ( 10 ), comprising: - a rotor winding ( 14 ) with an electrical conductor ( 24 ) of a first electrically conductive material; - a contact flag ( 16 ) a slip ring arrangement ( 12 ), whereby the contact lug ( 16 ) consists of a second electrically conductive material different from the first electrical material; A contacting element ( 26 ) which is adapted to make electrical contact between the electrical conductor ( 24 ) of the rotor winding ( 14 ) and the contact flag ( 16 ) to produce; wherein the contacting element ( 26 ) is adapted, via a first contact surface ( 26b ) makes electrical contact with the electrical conductor ( 24 ) of the rotor winding ( 14 ) and via a second contact surface ( 26c ) makes electrical contact with the contact lug ( 16 ), wherein the contacting element ( 26 ) at least at the first contact surface ( 26b ) comprises a third electrically conductive material other than the first electrical material. Electric rotor ( 10 ) according to claim 1, wherein the first electrically conductive material comprises or consists of aluminum, and / or wherein the second electrically conductive material comprises or consists of copper, and / or wherein the third electrically conductive material comprises or consists of tin. Electric rotor ( 10 ) according to claim 1 or 2, wherein the contacting element ( 26 ) is adapted to the electrical conductor ( 24 ) at least partially receive and at least partially surround, wherein an inner surface of the Kontaktierelements ( 26 ) forms the first contact surface. Electric rotor ( 10 ) according to claim 3, wherein the contacting element ( 26 ) at the first contact surface ( 26b ) a relief-like structuring ( 30 ), which is designed, at least partially in the electrical conductor ( 24 ) to penetrate. Electric rotor ( 10 ) according to claim 4, wherein the relief-like structuring ( 30 ) has toothing and / or serration which has a relief depth of at least 1 mm, preferably at least 2 mm, more preferably at least 3 mm, even more preferably at least 4 mm, most preferably at least 5 mm, and is preferably designed to one the electrical conductor ( 24 ) surrounding paint layer ( 24a ) and / or insulating layer during compression of the contacting element ( 26 ) at least in places to penetrate. Electric rotor ( 10 ) according to one of the preceding claims, wherein the contacting element ( 26 ) a contacting body ( 26a ), which is integrally formed from the second electrically conductive material. Electric rotor ( 10 ) according to one of the preceding claims, wherein the electrical conductor ( 24 ) is formed as aluminum enameled wire. Electric rotor ( 10 ) according to one of the preceding claims, wherein the third electrically conductive material has a lower melting point than the second electrically conductive material. Method for providing an electrical contact between an electrical conductor ( 24 ) a rotor winding ( 14 ) of a first electrically conductive material and a contact lug ( 16 ) of a second electrically conductive material, comprising the steps: - providing a contact element ( 26 ), wherein the contacting element ( 26 ) is adapted, via a first contact surface ( 26b ) makes electrical contact with the electrical conductor ( 24 ) of the rotor winding ( 14 ) and via a second contact surface ( 26c ) makes electrical contact with the contact lug ( 16 ), wherein the contacting element ( 26 ) at least at the first contact surface ( 26b ) comprises a third electrically conductive material other than the first electrical material. - insertion of the electrical conductor ( 24 ) in the contact element ( 26 ) such that the contacting element ( 26 ) the electrical conductor ( 24 ) at least partially surrounds and the first contact surface the electrical conductor ( 24 ) is at least partially facing; - compressing the contacting element ( 26 ) such that the first contact surface ( 26b ) on the electrical conductor ( 24 ) at least partially rests and the contacting element ( 26 ) at least partially into the electrical conductor ( 24 ) and makes electrical contact with the electrical conductor ( 24 ) produces; Connecting the second contact surface of the contacting element ( 26 ) with the contact flag such ( 16 ) that an electrical contact between the second contact surface ( 26c ) of the contacting element ( 26 ) and the contact flag ( 16 ) consists. Method according to claim 9, wherein during compression of the contacting element ( 26 ) the contacting element ( 26 ) one on the electrical conductor ( 24 ) formed insulating layer ( 24a ) and / or lacquer layer penetrates at least in places. Method according to claim 9 or 10, wherein connecting the second contact surface ( 26c ) of the contacting element ( 26 ) with the contact lug by soldering and / or welding.

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