DE4137816C1 - Flat commutator for universal motors and generators - includes running surface made of graphite carbon@ with metal additive and copper@ alloy - Google Patents

Abstract

A flat commutator for universal motors and generators, includes a running surface made of graphitic carbon with metal additives, and a copper alloy section with contact hooks. A copper plate stamped section with triangular penetrations is connected to the carbon. The latter is produced using ceramic technology, using a moulding which incorporates heat resistant plastic. The moulding pref. includes one or more of the group polyetherimide, polyether sulphone, polyether ketone, polyphenylene sulphide, polyimide or polyphenylclinoxaline. ADVANTAGE - The commutator has a wide range of uses and is simple to produce.

Description

The invention relates to a flat commutator according to the preamble of claim 1. This is a flat design commutator and Hook version for universal motors and generators on the Basis of the metal and plastic composite technologies for the operation in Low and low voltage areas with relatively high currents loads and small transition voltages to the commutating Brush operation. The area of application is also intended for use in liquid media, e.g. B. as a long-term fuel pump drive guarantee. In addition to the application in automotive engineering, everyone other applications included the use of flat require commutators.

It is known to also use non-metallic materials for commutas to use door running surfaces of electric motors and generators, e.g. B. Graphite versions in ceramic or plastic binding. Also Combinations of graphitic and metallic composite materials fen have been described.

In DE-OS 39 11 579 (Nettelhoff KG. 11. 10. 1990) State of the art and a. a flask lector in triangular geometry on a graphical basis as well as the Process for its preparation disclosed. Here you make use of a copper-adhesive molding compound and designs the tread through a pressing process. The safety of the adhesive bin manure, e.g. B. against centrifugal forces by mechanical measures improved. The necessary and after also becomes copper adhesive Lamination of self-supporting insulating material phase through pressing processes realized.

In both cases, the isolating phase and the graphi table conductive phase adhesively bonded with copper. Act here only forces that their liability in the actual and formpro can train filen. To get a higher mecha on this system to install niche stability, the envelope profile is geome  trically redesigned so that gears, especially the graphically conductive phase, result in the high centrifugal forces to withstand. Are in the graphically leading phase such measures are also urgently required, as is known to be high filled plastic composites only form moderate adhesive bonds can.

For continuous operation within fuels, e.g. B. as a pump pen drive, highly filled graphite / plastic composites deserve one critical evaluation because of the inevitable impact of PONA (paraffins, olefins, naphthenes and aromatics) and ent speaking oxygen and nitrogen compounds temporal Changes in these systems may result.

The aim of the invention is that described Defects in the Adhesive Bonding of State of the Art only eliminate plastic-bonded carbon molding compounds and that To extend the field of application by also having a commutator run surfaces based on ceramic-bonded carbon can be used are.

The object of the invention derived from this is Flat commutators of compatible types, also for in situ liquid media operation, such as fuel pump drives places where copper adhesive bonds are of minor importance tion and where the advantages of ceramic bound gra Fit materials effectively used as commutator running surfaces will.

According to the invention, this object is achieved by the characterizing features of claim 1. A sheet metal stamping according to Fig. 1 ( 1 ) with, for example, triangular openings in the cutting planes of the hook contacts is used in such a way that the openings 50-80% undercut the area of the graphite blank to be worn. In this stamping process, a bending or crushing of the copper blank elements by approximately 90 degrees, which are arranged between the hook contacts, is simultaneously effected. In the trough-shaped side of the stamped and bent part, a concentrically perforated graphite disc of ceramic bond type is gem. Fig. 1 ( 2 ) fixed by means of a commercially available SMD conductive silver adhesive and inserted graphite side in the die of an injection press. The closed upper stamp covers the hook contacts form-fittingly, so that the entire system according to FIG. 2 ( 2 ) can be fixed with an injection molding process with a special filled plastic material.

Both thermosets, e.g. B. Phenol / cresol form masses as well as thermoplastics with high permanent heat resistance abilities are used.

The permanent and mechanically safe connection of the system is exclusively through the plastic binding by means of triangular breakthroughs. A prerequisite for this is sufficient mechanical stability of the graphitic phase, in whose surface and pore structure is an insoluble spatial Bond takes place. When using ungraphed technical carbon composite ceramic bond type given this, the natural porosity of this material a volume commitment guaranteed. The stability of this system is limited by the breaking strength of the carbon composite and, based on the use cases, lies on the safe Page.

Also when using plastic-bonded graphite discs their final hardening together in the die with the insulating Perform injection molding material. This results in and non-positive as well as gap-free and mechanically difficult to loosen Bare intermediate bonds also in the thickness range up to approx. 100 microns.

The SMD adhesive can be applied using pad printing or Dispensers take place after the graphitron insertion thermal curing process should follow if a rear spraying with the insulating support system is completely excluded shall be.  

The commutator is feathered into wedge-shaped lamellae e.g. B. by cutting the carbon / copper phases up background in the insulating phase.

For the use of the commutation device within Fuels are plastic binders that are used in addition to a high chemical also have a high geometric resistance. The Resistance to PONA and its alcohols, ketones, esters, Aldehydes, acids, etc. must be guaranteed.

Preferred groups are:

• - polyetherimides;
• - polyether sulfones;
• - polyether ether ketones;
• - polyphenylene sulfides;
• - polyimides;
• - Polyphenylquinoxalines, or their imides;
• - phenol / cresol resins;
• - Polyester molding compounds, glass fiber types, u. a.

Embodiments 1. Flat commutator with technical coal

A stamped / bent part is used in accordance with. Fig. 1 ( 1 ), which is coated on the trough base with a silver conductive adhesive. Then a perforated graphite disc of ceramic binding type according to Fig. 1 ( 2 ) is fixed and thermally hardened. With usual epoxy binding at 130 to 180 ° C and over a period of about 15 min, the use of a continuous band heating channel is advisable.

This composite material is used in an injection molding tool Central mandrel transferred so that the carbon blank on the Lower stamp with sprue and ejector comes to rest. The closed tool covers the contact hook surfaces  form-fitting. In the assigned hollow profile shape at Mouthpiece temperatures up to 340 ° C a mineral or glass extruded polyphenylene sulfide material. The The plastic part of this material also penetrates the upper structure of the graphite material and creates a gap-free permanent connection of the overall system via the triangular Breakthroughs in the Cu sheet metal body. By the recrystallisa tion properties of the polyphenylene sulfide and its volume The wettability of the technical coal becomes a permanent mecha nical stability guaranteed that only from Mineral acids of higher concentrations can be attacked.

2. Flat commutator with plastic graphite

It becomes a Cu stamped / bent part tamped with conductive adhesive inserted and in the trough a plastic graphite high elec transferred to conductivity. This plastic bound Gra Fit material consists of B. from 90 mass% of a natural or Electrographite or a graphite mixture and 10 mass% of one Thermoplastic or thermoset material.

The procedure is as set out in Example 1.

A mixture of insulating materials is expedient in the case of the extrusion press zeß used from a graphite mixture material reactive plastic. The common curing in Die secures a gap-free on the triangular openings and permanent fixation with intermediate vertebral networks.

On the possibilities of applying thermal aging processes for higher resistance training are pointed out.

Claims (7)

1. Flat commutator for universal motors and generators with treads made of graphite carbons including metallic additives and in conjunction with adhesive copper deposits and contact hooks, characterized in that a copper sheet stamped / bent part with openings triangular in the cutting planes of the hook contacts and bending deformation between the Hook contacts ver is used and that through the breakthroughs a gap-free positive and non-positive connection of the tread made of graphite carbon, which was manufactured according to ceramic technologies, with the necessary insulating molded part made of permanent heat-resistant and thermally curable plastics is volume-adhesive and that the tread is one Feathering of the commutator bars between the hook contacts. 2. Flat commutator according to claim 1, characterized ge indicates that the tread is made of plastic graphite materials. 3. Flat commutator according to claim 1, characterized in that one or more materials from the following groups are used for the molded insulating part and the binding of the overall system:
Polyetherimides, polyether sulfones, polyether ether ketones, polyphenylene sulfides, polyimides, polyphenylquinoxalines or those imides, phenol / cresol resins, polyester molding compositions of glass fiber types, among others 4. Flat commutator according to one of claims 1 to 3, characterized characterized in that the copper deposit for Image of the graphitic material blanks with a silver lead adhesive of the SMD type.   5. Process for the production of flat commutators according to a of claims 1 to 4, characterized records that the copper sheet molding with triangular Breakthroughs punched in the cutting planes of the hook contacts and bent or squeezed by 90 degrees between the hook contacts becomes. 6. The method according to claim 5, characterized records that by bending or crushing produced trough with an SMD conductive adhesive, the graphic round blank is inserted and thermally fixed. 7. The method according to claim 5 or 6, characterized characterized in that the material described so transferred into an injection molding tool with a central mandrel is that when the tool is closed, the hook contacts form are covered and a mineral or glass fiber reinforced plastic material according to claim 3 ge is sprayed and cured.