EP1702390B1 - Carbon brush and method and material for the production thereof - Google Patents

Carbon brush and method and material for the production thereof Download PDF

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Publication number
EP1702390B1
EP1702390B1 EP04803858A EP04803858A EP1702390B1 EP 1702390 B1 EP1702390 B1 EP 1702390B1 EP 04803858 A EP04803858 A EP 04803858A EP 04803858 A EP04803858 A EP 04803858A EP 1702390 B1 EP1702390 B1 EP 1702390B1
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EP
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Prior art keywords
metal
carbon brush
sintering
base
pulverulent
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German (de)
French (fr)
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EP1702390A1 (en
Inventor
Gerhard Bachauer
Christian Böttger
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Hoffmann and Co Elektrokohle AG
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Hoffmann and Co Elektrokohle AG
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    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01R—ELECTRICALLY-CONDUCTIVE CONNECTIONS; STRUCTURAL ASSOCIATIONS OF A PLURALITY OF MUTUALLY-INSULATED ELECTRICAL CONNECTING ELEMENTS; COUPLING DEVICES; CURRENT COLLECTORS
    • H01R39/00—Rotary current collectors, distributors or interrupters
    • H01R39/02—Details for dynamo electric machines
    • H01R39/38—Brush holders
    • H01R39/39—Brush holders wherein the brush is fixedly mounted in the holder
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01R—ELECTRICALLY-CONDUCTIVE CONNECTIONS; STRUCTURAL ASSOCIATIONS OF A PLURALITY OF MUTUALLY-INSULATED ELECTRICAL CONNECTING ELEMENTS; COUPLING DEVICES; CURRENT COLLECTORS
    • H01R39/00—Rotary current collectors, distributors or interrupters
    • H01R39/02—Details for dynamo electric machines
    • H01R39/18—Contacts for co-operation with commutator or slip-ring, e.g. contact brush
    • H01R39/20—Contacts for co-operation with commutator or slip-ring, e.g. contact brush characterised by the material thereof

Definitions

  • Carbon brushes for electric motors or generators must be attached to a holder that provides the necessary system pressure on the commutator or the like. And allows the wear of the carbon brush corresponding Nachvantterrorism.
  • a particularly suitable for the carbon brush because of its simplicity, cost-effectiveness and low weight carrier is a leaf spring, which can take over the function of power transmission in addition to the function of the holder and guide. However, it raises the problem of attachment of the carbon brush to the leaf spring such that on the one hand, the required mechanical strength in continuous operation and on the other hand, the transmission of high currents is ensured.
  • a carbon brush according to the preamble of claim 1 is known, which is attached to a serving as a support leaf spring by welding or soldering and tinned for this purpose on the surface to be connected to the carrier, nickel-plated or metallized in any other way.
  • Out DE 40 40 002 A1 is a carbon brush for a gasoline pump motor is known, which is soldered to a serving as a leaf spring and for this purpose has a solderable layer consisting of a copper layer and a deposited thereon tin layer.
  • a solderable layer consisting of a copper layer and a deposited thereon tin layer.
  • US 5270504 A is a sliding contact element, such.
  • carbon brush known which has a layer structure of alternating copper-free and copper-containing graphite layers, wherein in the copper-free graphite layers, a filler material is included, which consists of a metal or a metal alloy having a lower melting temperature than copper.
  • a metal layer for a soldered or welded connection with a metallic carrier is not provided.
  • the invention has for its object to provide a carbon brush and a method and a material for their production, which allows a simple, mechanically and electrically highly resilient connection with a leaf spring.
  • a carbon brush which in addition to the usual, single or multilayer main body of pressed and sintered carbon material has at least one outer layer of metallic material, which ensures the weldability or solderability of the carbon brush, said metal layer also produced by pressing and sintering and connected to the main body.
  • a suitable welding method eg ultrasonic welding, laser welding or the like
  • soldering must be applied and also for the production of carbon brushes with a weldable metal layer, a material must be available, on the one hand in the powder metallurgy processing well with the carbon material of the main body of the carbon brush connects and on the other hand with the selected method well to weld or solder.
  • pure copper and its alloys as well as iron or steel are not suitable because their coefficient of thermal expansion and modulus of elasticity is not compatible with that of the carbon material of the main body of the carbon brush in the sintering process. Materials that are similar to the carbon material of the main body of the carbon brush, are also eliminated because they can not be welded due to the contained graphite part.
  • a metallic material in the form of a powder mixture of a component A, a ductile and low-melting component B and possibly further additives C both needs, namely the good connection by pressing and sintering with the functional carbon material of the body of the carbon brush on the one hand and the good weldability or solderability on the other hand at the same time.
  • the constituent A constitutes the predominant part, preferably more than 80%, of the material and preferably consists of copper or a copper alloy with, for example, Sn, Zn, Ni or Ag. It is preferably in powder form with a mean diameter D 50 of 15 to 25 microns before.
  • Component B is an additional metal which has a higher ductility and lower melting point than component A.
  • the melting point is 400 ° C or below and the elongation at break is 5% or above.
  • Component B is preferably Sn or an alloy of Sn with, for example, Cu, Ag, Sb, Zn, Ga, In, Bi or Pb.
  • the metal component B may also consist of In and / or Bi or an alloy with In or Bi. Its proportion of the total powder mixture of the material is preferably 1.5 to 15 percent by weight.
  • the additional metal B is preferably present in an average particle size D 50 of 15 to 35 microns.
  • the material may preferably contain one or more non-metallic, organic and / or inorganic additives C in powder form.
  • non-metallic, organic and / or inorganic additives C examples include stearates, graphite, talc, SiC or Al 2 O 3 .
  • Their average grain size D 50 is preferably not more than 20 microns.
  • the specified material can be powder metallurgically properly processed by pressing and sintering and combines perfectly with the functional layer (body) of the carbon brush to form a metal layer with excellent weldability and solderability. It has been found that during pressing and sintering, the low-melting and ductile metal B wets the base metal A, but does not or little diffuses into it.
  • the base metal A and at least the major part of the further metal B form two separate metal phases intimately bonded together by pressing and sintering, but substantially unalloyed with each other.
  • the heat treatment i. H. sintering the metal layer at a temperature lower than the melting point of the base metal A but higher than the melting point of the further metal B. It is thus preferably a liquid sintering in which the further metal B is in the liquid phase, while the base metal A is in a solid, powdery phase.
  • the sintering temperature is advantageously in the range of 300 to 700 ° C, preferably in the range of 400 to 500 ° C.
  • the non-metallic, organic or inorganic additive C is not wetted by the metal B in the sintering process, thereby preventing an undesirably large diffusion of the metal B into the parent metal A.
  • the carbon brush has a main body 1, which is produced in a conventional manner single-layer or multi-layer of a conventional carbon material for carbon brushes, in particular a graphite mixture with additives, by pressing and heat treatment (sintering).
  • a conventional carbon material for carbon brushes in particular a graphite mixture with additives
  • the well weldable or solderable metal layer (2) which is also made of the abovementioned powdery material according to the invention by pressing and optionally sintering and is permanently connected to the base body 1.
  • Base body 1 and weldable metal layer 2 can be produced simultaneously by pressing and sintering and connected to each other, or it can be the base body 1 prefabricated and subsequently formed the weldable metal layer 2 by pressing and sintering.
  • the weldable metal layer 2 makes it possible to attach the entire carbon brush by welding to a leaf spring 3, for example by welding points 4 or z. B. by a continuous weld.
  • the thickness of the sintered metal layer 2 depends on the requirements of the welding or soldering method selected for the connection to the leaf spring 3.
  • the thickness of the metal layer 2 is in the range of 0.2 to 5 mm.
  • a thickness of the metal layer 2 of less than 1 mm, in particular in the range of 0.2 to 0.5 mm, should generally suffice.
  • a thickness of at least 1 mm, z. B. in the range of 2 to 4 mm be advantageous.

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  • Motor Or Generator Current Collectors (AREA)
  • Powder Metallurgy (AREA)
  • Manufacture Of Motors, Generators (AREA)
  • Carbon And Carbon Compounds (AREA)
  • Laminated Bodies (AREA)

Abstract

Carbon brush comprising a base body produced from carbon material by pressing and optionally sintering and a layer of a metallic material applied to an outer surface of the base body by pressing and possibly sintering, the metal layer being connectable to a metallic carrier by welding or soldering.

Description

Kohlebürsten für elektrische Motoren oder Generatoren müssen an einer Halterung befestigt sein, die für den nötigen Anlagedruck am Kommutator oder dgl. sorgt und die dem Verschleiß der Kohlebürste entsprechende Nachführbewegung ermöglicht. Ein wegen seiner Einfachheit, Kostengünstigkeit und niedrigen Gewichts besonders geeigneter Träger für die Kohlebürste ist eine Blattfeder, die zusätzlich zur Funktion der Halterung und Führung auch die Funktion der Stromübertragung übernehmen kann. Es stellt sich aber das Problem der Befestigung der Kohlebürste an der Blattfeder derart, dass einerseits die erforderliche mechanische Festigkeit im Dauerbetrieb und andererseits die Übertragung hoher Ströme gewährleistet ist.Carbon brushes for electric motors or generators must be attached to a holder that provides the necessary system pressure on the commutator or the like. And allows the wear of the carbon brush corresponding Nachführbewegung. A particularly suitable for the carbon brush because of its simplicity, cost-effectiveness and low weight carrier is a leaf spring, which can take over the function of power transmission in addition to the function of the holder and guide. However, it raises the problem of attachment of the carbon brush to the leaf spring such that on the one hand, the required mechanical strength in continuous operation and on the other hand, the transmission of high currents is ensured.

Aus DE 102 07 406 A1 ist eine Kohlebürste gemäß dem Oberbegriff des Anspruchs 1 bekannt, die an einer als Träger dienenden Blattfeder durch Schweißen oder Löten befestigt ist und zu diesem Zweck an der mit dem Träger zu verbindenden Fläche verzinnt, vernickelt oder in sonstiger Weise metallisiert ist.Out DE 102 07 406 A1 a carbon brush according to the preamble of claim 1 is known, which is attached to a serving as a support leaf spring by welding or soldering and tinned for this purpose on the surface to be connected to the carrier, nickel-plated or metallized in any other way.

Aus DE 40 40 002 A1 ist eine Kohlebürste für einen Benzinpumpenmotor bekannt, die an einer als Träger dienenden Blattfeder angelötet ist und zu diesem Zweck eine lötbare Schicht aufweist, die aus einer Kupferschicht und einer auf dieser aufgebrachten Zinnschicht besteht. Mit derartigen Metallisierungen bzw. in der Regel galvanisch aufgebrachten Metallschichten ist es jedoch schwierig, eine Löt- oder Schweißverbindung zwischen Kohlebürste und Blattfeder herzustellen, die eine für den Dauerbetrieb ausreichende mechanische, thermische und elektrische Belastbarkeit aufweist. Insbesondere ist der Spannungsausgleich zwischen der Kohlebürste und der Blattfeder aufgrund des unterschiedlichen Elastizitätsmodus und thermischen Ausdehnungskoeffizienten problematisch.Out DE 40 40 002 A1 is a carbon brush for a gasoline pump motor is known, which is soldered to a serving as a leaf spring and for this purpose has a solderable layer consisting of a copper layer and a deposited thereon tin layer. With such metallizations or usually galvanically applied metal layers, however, it is difficult to produce a soldering or welding connection between carbon brush and leaf spring, which has a sufficient for continuous operation mechanical, thermal and electrical load capacity. In particular, the stress balance between the carbon brush and the leaf spring is problematic due to the different elasticity mode and thermal expansion coefficient.

Aus DE 24 44 957 A1 ist es bekannt, eine mit einer löt- oder schweißbaren Metallschicht versehene Kohlebürste dadurch herzustellen, dass eine Schicht aus pulverförmigem kohlehaltigen Material und eine Schicht aus Metallpulver gemeinsam verpresst und dann wärmebehandelt werden. Das Metallpulver besteht aus Kupfer.Out DE 24 44 957 A1 It is known to produce a carbon brush provided with a solderable or weldable metal layer by co-pressing and then heat-treating a layer of pulverulent carbonaceous material and a layer of metal powder. The metal powder is made of copper.

Aus US 3,601,645 A1 ist es bekannt, eine elektrische Kontaktbürste mit einem aus Metall und Kohlewerkstoff bestehenden Grundkörper und einer mit diesem unlösbar verbundenen Metallschicht durch Pressen und Sintern eines pulverförmigen Metall-Kohlewerkstoffs für den Grundkörper und eines Metallpulvers herzustellen, wobei die Metallschicht aus Kupfer, Eisen oder einer Legierung bestehen kann.Out US 3,601,645 A1 It is known to produce an electrical contact brush with a basic body consisting of metal and carbon material and a metal layer undetachably connected thereto by pressing and sintering a pulverulent metal-carbon material for the basic body and a metal powder, the metal layer consisting of copper, iron or an alloy can.

Aus US 5270504 A ist ein Schleifkontaktelement, wie z. B. Kohlebürste, bekannt, das einen Schichtenaufbau aus abwechselnd kupferfreien und Kupfer enthaltenden Graphitschichten aufweist, wobei in den kupferfreien Graphitschichten ein Zusatzmaterial enthalten ist, welches aus einem Metall oder eine Metalllegierung mit niedrigerer Schmelztemperatur als Kupfer besteht. Eine Metallschicht für eine Löt- oder Schweißverbindung mit einem metallischem Träger ist nicht vorgesehen.Out US 5270504 A is a sliding contact element, such. As carbon brush, known which has a layer structure of alternating copper-free and copper-containing graphite layers, wherein in the copper-free graphite layers, a filler material is included, which consists of a metal or a metal alloy having a lower melting temperature than copper. A metal layer for a soldered or welded connection with a metallic carrier is not provided.

Aus DE 32 17 217 C2 ist es bekannt, eine Kontaktbürste durch Verpressen eines Bündels von metallbeschichteten Kohlenstofffasern herzustellen, wobei die Metallbeschichtung der Kohlenstofffasern u.a. aus Kupfer, Aluminium, Zinn, Eisen oder einer Legierung davon bestehen kann.Out DE 32 17 217 C2 It is known to produce a contact brush by pressing a bundle of metal-coated carbon fibers, wherein the metal coating of the carbon fibers may consist inter alia of copper, aluminum, tin, iron or an alloy thereof.

Der Erfindung liegt die Aufgabe zugrunde, eine Kohlebürste sowie ein Verfahren und einen Werkstoff für ihre Herstellung anzugeben, die eine einfache, mechanisch und elektrisch hoch belastbare Verbindung mit einer Blattfeder ermöglicht.The invention has for its object to provide a carbon brush and a method and a material for their production, which allows a simple, mechanically and electrically highly resilient connection with a leaf spring.

Die Lösung der Aufgabe ist in den Ansprüchen angegeben.The solution of the problem is specified in the claims.

Die Erfindung wird im Folgenden näher und anhand eines Ausführungsbeispiels erläutert.The invention will be explained in more detail below with reference to an exemplary embodiment.

Es ist kommerziell interessant, Kohlebürsten mit Blattfedern zu verschweißen, weil damit eine Verbindung realisiert werden kann, mit der hohe Ströme von mehr als 15 A übertragen werden können. Dies würde es erlauben, auch Motorbauarten auf diese kostengünstige Bauart umzustellen, die wegen zu hoher Anforderungen bezüglich der Stromstärke beim Blockiertest oder auch im Dauerbetrieb bisher nicht nach diesem Konzept gefertigt werden konnten. Motoren dieser Art, bei denen die Kohlebürste bei kleinen Abmessungen hohe Ströme übertragen muss, sind z.B. Stellantriebe in Kraftfahrzeugen wie z.B. Antriebe für Fensterheber, Sitzverstellungen, Schiebedächer, Spiegelverstellungen und dgl.It is commercially interesting to weld carbon brushes with leaf springs, because this can be realized a connection, with the high currents of more than 15 A can be transmitted. This would make it possible to convert even engine types to this cost-effective design, which could not be manufactured according to this concept due to high demands on the current during the blocking test or in continuous operation. Engines of this type in which the carbon brush at For example, actuators in motor vehicles such as drives for window regulators, seat adjusters, sunroofs, mirror adjustments and the like have to transmit high currents.

Erfindungsgemäß ist eine Kohlebürste vorgesehen, die neben dem üblichen, ein- oder mehrschichtigen Grundkörper aus gepresstem und gesinterten Kohlewerkstoff mindestens eine Außenschicht aus metallischem Werkstoff aufweist, die die Schweiß- oder Lötbarkeit der Kohlebürste sicherstellt, wobei diese Metallschicht ebenfalls durch Pressen und Sintern hergestellt und mit dem Grundkörper verbunden ist.According to the invention, a carbon brush is provided, which in addition to the usual, single or multilayer main body of pressed and sintered carbon material has at least one outer layer of metallic material, which ensures the weldability or solderability of the carbon brush, said metal layer also produced by pressing and sintering and connected to the main body.

Für das Schweißen oder Löten einer Kohlebürste muss ein geeignetes Schweißverfahren (z.B. Ultraschallschweißen, Laserschweißen oder dgl.) oder Lötverfahren angewendet werden und ferner muss für die Herstellung der Kohlebürsten mit einer schweißbaren Metallschicht ein Werkstoff zur Verfügung stehen, der sich einerseits bei der pulvermetallurgischen Verarbeitung gut mit dem Kohlewerkstoff des Grundkörpers der Kohlebürste verbindet und andererseits mit dem ausgewählten Verfahren gut zu schweißen oder zu löten ist. Es wurde gefunden, dass reines Kupfer und seine Legierungen sowie Eisen oder Stahl nicht geeignet sind, weil ihr Wärmeausdehnungskoeffizient und Elastizitätsmodul nicht mit dem des Kohlewerkstoffs des Grundkörpers der Kohlebürste im Sinterverfahren kompatibel ist. Werkstoffe, die dem Kohlewerkstoff des Grundkörpers der Kohlebürste ähnlich sind, scheiden ebenfalls aus, da sie sich, bedingt durch den enthaltenen Graphitanteil, nicht verschweißen lassen.For the welding or soldering of a carbon brush, a suitable welding method (eg ultrasonic welding, laser welding or the like) or soldering must be applied and also for the production of carbon brushes with a weldable metal layer, a material must be available, on the one hand in the powder metallurgy processing well with the carbon material of the main body of the carbon brush connects and on the other hand with the selected method well to weld or solder. It has been found that pure copper and its alloys as well as iron or steel are not suitable because their coefficient of thermal expansion and modulus of elasticity is not compatible with that of the carbon material of the main body of the carbon brush in the sintering process. Materials that are similar to the carbon material of the main body of the carbon brush, are also eliminated because they can not be welded due to the contained graphite part.

Es wurde erfindungsgemäß gefunden, dass ein metallischer Werkstoff in Form eines Pulvergemisches aus einem Bestandteil A, einem duktilen und niedrigschmelzenden Bestandteil B und ggf. weiteren Zusatzstoffen C beiden Notwendigkeiten, nämlich der guten Verbindung durch Pressen und Sintern mit dem funktionellen Kohlewerkstoff des Grundkörpers der Kohlebürste einerseits und der guten Schweißbarkeit oder Lötbarkeit andererseits gleichzeitig gerecht wird.It has been found according to the invention that a metallic material in the form of a powder mixture of a component A, a ductile and low-melting component B and possibly further additives C both needs, namely the good connection by pressing and sintering with the functional carbon material of the body of the carbon brush on the one hand and the good weldability or solderability on the other hand at the same time.

Erfindungsgemäß macht der Bestandteil A den überwiegenden Teil, vorzugsweise mehr als 80%, des Werkstoffs aus und besteht vorzugsweise aus Kupfer oder einer Kupferlegierung mit z.B. Sn, Zn, Ni oder Ag. Er liegt vorzugsweise in Pulverform mit einem mittleren Durchmesser D50 von 15 bis 25 µm vor.According to the invention, the constituent A constitutes the predominant part, preferably more than 80%, of the material and preferably consists of copper or a copper alloy with, for example, Sn, Zn, Ni or Ag. It is preferably in powder form with a mean diameter D 50 of 15 to 25 microns before.

Der Bestandteil B ist ein zusätzliches Metall, das eine höhere Duktilität und niedrigeren Schmelzpunkt aufweist als der Bestandteil A. Vorzugsweise liegt der Schmelzpunkt bei 400°C oder darunter und die Bruchdehnung bei 5% oder darüber. Der Bestandteil B besteht vorzugsweise aus Sn oder eine Legierung von Sn mit z.B. Cu, Ag, Sb, Zn, Ga, In, Bi oder Pb. Der Metallbestandteil B kann auch aus In und/oder Bi oder einer Legierung mit In oder Bi bestehen. Sein Anteil an der gesamten Pulvermischung des Werkstoffs beträgt vorzugsweise 1,5 bis 15 Gewichtsprozent. Das zusätzliche Metall B liegt vorzugsweise in einer mittleren Korngröße D50 von 15 bis 35 µm vor.Component B is an additional metal which has a higher ductility and lower melting point than component A. Preferably, the melting point is 400 ° C or below and the elongation at break is 5% or above. Component B is preferably Sn or an alloy of Sn with, for example, Cu, Ag, Sb, Zn, Ga, In, Bi or Pb. The metal component B may also consist of In and / or Bi or an alloy with In or Bi. Its proportion of the total powder mixture of the material is preferably 1.5 to 15 percent by weight. The additional metal B is preferably present in an average particle size D 50 of 15 to 35 microns.

Zusätzlich kann der Werkstoff vorzugsweise einen oder mehrere nichtmetallische, organische und/oder anorganische Zusätze C in Pulverform enthalten. Als derartige Zusätze kommen z.B. Stearate, Graphit, Talkum, SiC oder Al2O3 in Betracht. Ihre mittlere Korngröße D50 beträgt vorzugsweise nicht mehr als 20 µm.In addition, the material may preferably contain one or more non-metallic, organic and / or inorganic additives C in powder form. Examples of such additives are stearates, graphite, talc, SiC or Al 2 O 3 . Their average grain size D 50 is preferably not more than 20 microns.

Ein bevorzugtes Beispiel zur Zusammensetzung des Werkstoffs ist (Angaben in Gewichtsprozent):

  1. A: 92% Cu (D50 15 - 25 µm)
  2. B: 7,5% Sn (D50 15 - 55 µm)
  3. C: 0,5% Graphit (D50 ≤ 20 µm).
A preferred example of the composition of the material is (in percent by weight):
  1. A: 92% Cu (D 50 15 - 25 μm)
  2. B: 7.5% Sn (D 50 15 - 55 μm)
  3. C: 0.5% graphite (D 50 ≤ 20 μm).

Der angegebene Werkstoff lässt sich pulvermetallurgisch einwandfrei durch Verpressen und Sintern verarbeiten und verbindet sich hervorragend mit der funktionellen Schicht (Grundkörper) der Kohlebürste zur Bildung einer Metallschicht mit hervorragender Schweiß- und Lötbarkeit. Es hat sich gezeigt, dass beim Pressen und Sintern das niedrigschmelzende und duktile Metall B das Grundmetall A benetzt, aber in dieses nicht oder wenig eindiffundiert.The specified material can be powder metallurgically properly processed by pressing and sintering and combines perfectly with the functional layer (body) of the carbon brush to form a metal layer with excellent weldability and solderability. It has been found that during pressing and sintering, the low-melting and ductile metal B wets the base metal A, but does not or little diffuses into it.

Dadurch wird gewährleistet, dass der überwiegende oder jedenfalls ausreichende Teil des Metalls B nach dem Sintern nicht mit dem Metall A legiert ist, sondern rein vorliegt und somit die gewünschte Duktilität der Metallschicht erzielt wird. Durch die Duktilität des Werkstoffs wird ein Spannungsausgleich zwischen dem Grundkörper 1 der Kohlebürste und der Schweißbahn-Metallschicht (2) einerseits und der mit der Metallschicht (2) verschweißten Blattfeder andererseits ermöglicht.This ensures that the predominant or at least sufficient part of the metal B after sintering is not alloyed with the metal A, but is pure and thus the desired ductility of the metal layer is achieved. Due to the ductility of the material, a voltage compensation between the main body 1 of the carbon brush and the welding track metal layer (2) on the one hand and with the metal layer (2) welded leaf spring on the other hand allows.

Mit anderen Worten, in der durch Pressen und Sintern hergestellten Sintermetallschicht 2 bilden das Grundmetall A und zumindest der überwiegende Teil des weiteren Metalls B zwei getrennte Metallphasen, die zwar durch das Pressen und Sintern innig miteinander verbunden, aber im wesentlichen nicht miteinander legiert sind.In other words, in the sintered metal layer 2 produced by pressing and sintering, the base metal A and at least the major part of the further metal B form two separate metal phases intimately bonded together by pressing and sintering, but substantially unalloyed with each other.

Vorzugsweise wird die Wärmebehandlung, d. h. das Sintern der Metallschicht bei einer Temperatur, die niedriger als der Schmelzpunkt des Grundmetalls A, aber höher als der Schmelzpunkt des weiteren Metalls B liegt, durchgeführt. Es handelt sich somit vorzugsweise um eine Flüssigsinterung, bei der das weitere Metall B in flüssiger Phase, das Grundmetall A dagegen in fester, pulverförmiger Phase vorliegt. Wenn das Grundmetall A Kupfer und das weitere Metall B Zinn ist, liegt die Sintertemperatur vorteilhafterweise im Bereich von 300 bis 700°C, vorzugsweise im Bereich von 400 bis 500°C.Preferably, the heat treatment, i. H. sintering the metal layer at a temperature lower than the melting point of the base metal A but higher than the melting point of the further metal B. It is thus preferably a liquid sintering in which the further metal B is in the liquid phase, while the base metal A is in a solid, powdery phase. When the base metal A is copper and the other metal B is tin, the sintering temperature is advantageously in the range of 300 to 700 ° C, preferably in the range of 400 to 500 ° C.

Der nichtmetallische, organische oder anorganische Zusatz C wird vom Metall B beim Sinterprozess nicht benetzt und verhindert dadurch eine unerwünscht große Diffusion des Metalls B in das Grundmetall A.The non-metallic, organic or inorganic additive C is not wetted by the metal B in the sintering process, thereby preventing an undesirably large diffusion of the metal B into the parent metal A.

Die beigefügte Zeichnung zeigt schematisch eine an eine Blattfeder angeschweißte Kohlebürste gemäß der Erfindung.The accompanying drawing shows schematically a welded to a leaf spring carbon brush according to the invention.

Die Kohlebürste hat einen Grundkörper 1, der in üblicher Weise einschichtig oder auch mehrschichtig aus einem üblichen Kohlewerkstoff für Kohlebürsten, insbesondere einer Graphitmischung mit Zusätzen, durch Pressen und Wärmebehandlung (Sintern) hergestellt ist. Mit dem Grundkörper 1 verbunden ist die gut schweiß- oder lötbare Metallschicht (2), die aus den o.g. erfindungsgemäßen pulverförmigen Werkstoff ebenfalls durch Pressen und ggf. Sintern hergestellt und mit dem Grundkörper 1 unlösbar verbunden ist. Grundkörper 1 und schweißbare Metallschicht 2 können gleichzeitig durch Verpressen und Sintern hergestellt und miteinander verbunden werden, oder es kann der Grundkörper 1 vorgefertigt und an diesen nachträglich die schweißbare Metallschicht 2 durch Pressen und Sintern angeformt werden.The carbon brush has a main body 1, which is produced in a conventional manner single-layer or multi-layer of a conventional carbon material for carbon brushes, in particular a graphite mixture with additives, by pressing and heat treatment (sintering). Connected to the main body 1 is the well weldable or solderable metal layer (2), which is also made of the abovementioned powdery material according to the invention by pressing and optionally sintering and is permanently connected to the base body 1. Base body 1 and weldable metal layer 2 can be produced simultaneously by pressing and sintering and connected to each other, or it can be the base body 1 prefabricated and subsequently formed the weldable metal layer 2 by pressing and sintering.

Die gut schweißbare Metallschicht 2 ermöglicht es, die gesamte Kohlebürste durch Schweißen an einer Blattfeder 3 zu befestigen, beispielsweise durch Schweißpunkte 4 oder z. B. durch eine durchgehende Schweißnaht.The weldable metal layer 2 makes it possible to attach the entire carbon brush by welding to a leaf spring 3, for example by welding points 4 or z. B. by a continuous weld.

Die Dicke der Sintermetallschicht 2 richtet sich nach den Erfordernissen des für die Verbindung mit der Blattfeder 3 gewählten Schweiß- oder Lötverfahrens. Vorzugsweise liegt die Dicke der Metallschicht 2 im Bereich von 0,2 bis 5 mm. Für eine Lötverbindung mit der Blattfeder 2 dürfte in der Regel eine Dicke der Metallschicht 2 von weniger als 1 mm, insbesondere im Bereich von 0,2 bis 0,5 mm ausreichen. Für eine Schweißverbindung dürfte in der Regel eine Dicke von mindestens 1 mm, z. B. im Bereich von 2 bis 4 mm, vorteilhaft sein.The thickness of the sintered metal layer 2 depends on the requirements of the welding or soldering method selected for the connection to the leaf spring 3. Preferably, the thickness of the metal layer 2 is in the range of 0.2 to 5 mm. For a solder connection to the leaf spring 2, a thickness of the metal layer 2 of less than 1 mm, in particular in the range of 0.2 to 0.5 mm, should generally suffice. For a welded joint, a thickness of at least 1 mm, z. B. in the range of 2 to 4 mm, be advantageous.

Claims (14)

  1. Carbon brush comprising a base body (1) produced from carbon material and a metal layer (2) which is applied to an outer surface of the base body and can be connected by welding or soldering to a metal carrier, the metal layer (2) being a layer made from metal powder by pressing and optionally sintering and undetachably bonded to the base body (1) by pressing and optionally sintering,
    characterized in that the metal layer (2) contains a base metal (A) and at least one further metal (B) of higher ductility and lower melting point than the base metal (A), the further metal (B) being present at least predominantly as a metal phase which is separate from the base metal (A) and is intimately bonded to the base metal (A) by pressing and optionally sintering but predominantly does not form an alloy therewith.
  2. Carbon brush according to claim 1,
    characterized in that the further metal (B) is so chosen that at sintering temperature in the liquid phase it wets the base metal (A) but does not diffuse into said base metal, or only slightly.
  3. Carbon brush according to claim 1 or 2,
    characterized in that the further metal (B) consists of tin, indium or bismuth or an alloy thereof.
  4. Carbon brush according to claim 1,
    characterized in that the further metal (B) has a melting point of not more than 400°C and a breakage elongation of not less than 5%.
  5. Carbon brush according any one of claims 1 to 4,
    characterized in that the further metal (B) is present in a proportion between 1.5 and 15% by weight of the metal layer (2)
  6. Carbon brush according to any one of claims 1 to 5,
    characterized in that the metal layer (2) additionally contains an additive (C) of non-metallic, organic and/or inorganic material.
  7. Carbon brush according to claim 6,
    characterized in that the non-metallic additive (C) contains stearates, graphite, talcum, SiC or Al2O3.
  8. Carbon brush according any one of claims 1 to 7,
    characterized in that the metal layer (2) thereof is connected to a carrier (3) made of metal by welding or soldering.
  9. Carbon brush according to claim 8,
    characterized in that the carrier is a leaf spring (3).
  10. Material for producing a weldable and/or solderable metal layer of a carbon brush according to one of claims 1 to 9, consisting of a powder mixture which contains a pulverulent main metal (A) and a pulverulent additive metal (B) of greater ductility and lower melting point than the main metal, wherein the main metal (A) is copper or a copper alloy and the additive metal (B) is tin, indium or bismuth or an alloy thereof, and wherein the material contains not more than 0.5 wt.-% of graphite.
  11. Material according to claim 10,
    characterized in that it contains a pulverulent additive (C) of non-metallic, organic and/or inorganic material.
  12. Material according to claim 10 or 11,
    characterized in that the additive metal (B) is present in a proportion of 1.5 to 15% by volume of the powder mixture.
  13. Method for producing a carbon brush comprising a base body of carbon material and a metal layer undetachably bonded thereto, comprising the steps:
    a) producing the base body by pressing and sintering of a pulverulent carbon-containing material;
    b) simultaneously with or following step a): producing the metal layer by pressing and sintering a pulverulent metallic material, the metal layer being bonded undetachably to the base body by pressing and sintering;
    c) the pulverulent metallic material contains a mixture of a pulverulent base metal A and at least one pulverulent further metal B of greater ductility and lower melting point than the base metal A; and
    d) the further metal B and the sintering temperature are so selected that during the sintering the further metal in the liquid phase wets the base metal A but does not, or only slightly, diffuse into the latter, whereby the further metal B is present at least predominantly as a metal phase separate from the base metal A and predominantly not alloyed therewith.
  14. Method according to claim 13,
    characterized in that the main metal A consists of copper or copper alloy and the further metal B of tin, indium or bismuth or an alloy thereof.
EP04803858A 2003-12-19 2004-12-14 Carbon brush and method and material for the production thereof Active EP1702390B1 (en)

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
DE10359896A DE10359896A1 (en) 2003-12-19 2003-12-19 Carbon brush and method and material for their production
PCT/EP2004/014235 WO2005064756A1 (en) 2003-12-19 2004-12-14 Carbon brush and method and material for the production thereof

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EP1702390A1 EP1702390A1 (en) 2006-09-20
EP1702390B1 true EP1702390B1 (en) 2007-12-05

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US (1) US20060260436A1 (en)
EP (1) EP1702390B1 (en)
JP (1) JP2007515146A (en)
CN (1) CN1902792A (en)
AT (1) ATE380408T1 (en)
DE (2) DE10359896A1 (en)
ES (1) ES2297520T3 (en)
WO (1) WO2005064756A1 (en)

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Publication number Priority date Publication date Assignee Title
DE102006051678A1 (en) * 2006-10-30 2008-05-15 Schunk Modultechnik Gmbh Sliding contact i.e. carbon brush, has two layers e.g. sliding surface-sided running layer and sliding surface lying layer, with surfaces turned towards each other, where lying layer consists of resistor material with resistance process
JP2008118831A (en) 2006-11-08 2008-05-22 Mabuchi Motor Co Ltd Metal graphite brush
DE102007026265B4 (en) 2007-06-05 2014-04-10 Gerhard Präzisionspresstechnik GmbH carbon brush
DE102008059478B4 (en) 2008-11-28 2015-07-30 Schunk Kohlenstofftechnik Gmbh Carbon brush for the transmission of high currents
EP2431488A4 (en) * 2009-04-28 2013-12-11 Taiho Kogyo Co Ltd Lead-free copper-based sintered sliding material and sliding part
FR2972082B1 (en) 2011-02-28 2013-03-29 Mersen France Amiens Sas CONTACT BROOM
DE102011015579B4 (en) * 2011-03-30 2017-03-23 Heraeus Deutschland GmbH & Co. KG Elastic sliding contact and method for its production
CN106329286B (en) * 2015-07-01 2019-06-11 苏州东南佳新材料股份有限公司 A kind of preparation method of EMU ground connection reflux unit brush
DE102017209340B4 (en) 2017-06-01 2022-12-15 Schunk Carbon Technology Gmbh Diverting device for diverting electrical currents
CN109244686B (en) * 2018-07-26 2021-06-18 合德华厦安防科技有限公司 Core rod for grounding system and preparation method thereof
WO2023086436A1 (en) * 2021-11-10 2023-05-19 National Electrical Carbon Products, Inc. Carbon brush

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Publication number Priority date Publication date Assignee Title
GB1259454A (en) * 1968-05-23 1972-01-05
DE2444957C2 (en) * 1974-09-20 1982-08-12 Robert Bosch Gmbh, 7000 Stuttgart Process for the production of a composite material from carbonaceous powder and metal powder
JPS57185685A (en) * 1981-05-09 1982-11-15 Toho Beslon Co Brush for electric machine and method of producing same
EP0525222B1 (en) * 1991-07-22 1995-05-31 Deutsche Carbone AG Sliding contact piece for high current densities
DE19900023A1 (en) * 1999-01-02 2000-07-06 Carbone Ag Production of sprung brush used on commutator of electric motor involves pressing conductive powder on strip of beryllium bronze sheet and sintering at temperature increasing elasticity of bronze
DE10207406A1 (en) * 2002-02-21 2003-09-11 K Tec Gmbh Holder for a carbon brush

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DE10359896A1 (en) 2005-07-21
CN1902792A (en) 2007-01-24
DE502004005669D1 (en) 2008-01-17
ATE380408T1 (en) 2007-12-15
WO2005064756A1 (en) 2005-07-14
US20060260436A1 (en) 2006-11-23
ES2297520T3 (en) 2008-05-01
JP2007515146A (en) 2007-06-07
EP1702390A1 (en) 2006-09-20

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