WO2003049258A1

WO2003049258A1 - Commutator for electric machines primarily starter motors and processing method for its production

Info

Publication number: WO2003049258A1
Application number: PCT/HU2002/000134
Authority: WO
Inventors: György Dutkay
Original assignee: Dutkay Gyoergy
Priority date: 2001-12-03
Filing date: 2002-12-02
Publication date: 2003-06-12
Also published as: HU0105241D0; WO2003049258A8; HUP0105241A2

Abstract

The subject of this invention is the way of forming the armature's commutator bars of the wire ends of the armature windings. The commutator consisting these and isolation material furthermore the processing method of these commutators will be discussed. The goal of this invention is that the armature parts of the rotating electric motors be more robust and reliable, equisolid both mechanically as well electrically. We achieve the above mentioned goal by forging the commutator bars from the armature windings wire end themselves and connect the wire pairs to each other with same forging and these formed commutator bars which are continuously connected to the armature winding separate from each other with an isolation ring that is fixed to the armature shaft. The commutator bars are embedded into the isolation or fixed on its surface with isolating ring.

Description

Commutator for electric machines primarily starter motors and processing method for its production

The subject of this invention is the commutator for electric machines with forged bars created from the wire ends of windings and the method of processing way of its production.

The commutator electric motors are made with current technology as following: the shaft is pressed into the core's hole, the commutator is fixed to the shaft and the windings are situated in the slots of the core furthermore the winding ends are connected to the commutator bars as prescript by the scheme. The commutator is fixed on the armature shaft in order to supply the current for the rotating armature windings in the correct direction depending on the relation of the stator's magnetic field. The commutator is the most complex and most stressed part of the electric machines, because even the starter motor of a medium size vehicle starter can up to 10000 as free spin RPM and has to take 1000 A current under stop in everyday working conditions. The current technical practice used generally is such that the copper bars are isolated from each other and from the shaft, are situated on the cylindrical surface or alternatively on the face of the commutator. The bars are fixed in their position relative to each other and to the shaft and are embedded into plastic during the commutator production. This way of processing is very common and well known, related to this is the No 209225 Hungarian patent which has a number of valuable partial solutions.

The commutator itself can be produced a number of way, its bars have to connect firmly both mechanically as well as electrically to the end of the windings to form the circuit of the armature. This process can made with soldering or thermocompression or resistance welding, that is normally carried out by the equipments like these described in the Us.3,045,103 patent or such similar machines. The common disadvantage of the thermal connecting methods is that the heating of the soldering or brazing material is close to the melting point of the copper bars and produces a thermal degradation of the embedding isolation material which becomes weak. Further more, because of the heat shock the copper become softened and not resistant enough against the brush wearing effect. It is known from the American Technology, Inc. Application Brief #2 Armature 4/96 and the www.amtechultrasonic.com web site description that by using ultrasonic welding to connect the wires to the commutator bars we can avoid the heat shock, but the vibration effect damages the thin isolating walls between the bars and weakens the embedding of the bars into the isolation. Because of this fact this method is not in wide spread use.

Generally speaking the recent technical practice on the connecting technology of the wires and commutator bars produce more less the same reliability as could be independently carried out of the isolation's wearing ability. The recent practice in which the commutator producing is separated from the armature winding and the joining process can not produce an equivalent firm connection neither mechanically nor electrically just to protect the isolation embedding.

The goal of this invention is that the armature parts of the rotating electric motors make more durable and reliable, equisolid both mechanically as well as electrically. We can achieve the above mentioned goal through forging the commutator bars from the armature windings end wires themselves and connecting the wires pairs to each other with same forging and these formed commutator bars which are therefore continuous and part of the armature winding and separated from each other with an isolation ring that is fixed to the armature shaft. The commutator bars are embedded into the isolation or fixed on its surface with an isolating ring. In order that the invention can be fully understood we describe three alternative examples which are as follow: The first alternative example

1. figure the armature's core body in wired status

2. figure the commutator bars formed of winding ends

3. figure the bars in working position on reduced diameter related to figure 2

4. figure the bars pressed on the isolating ring and on the shaft the second alternative example

5. figure the welded commutator bars assembled with inner isolating ring

6. figure commutators's isolating rings in two different forms

7. figure the commutator bars fixing way to the shaft the third alternative example

8. figure assembling method of the inner isolating ring

9. figure the running surface's forming method for brush contact 10. figure the outer fixing ring on the running surface. Each example is applicable to a medium size starter motor and reflects its proportions. The first example

The 3 outer wires and the 4 inner ones are situated into the 2 slots of the 1 core and the wires are longer related to the conventional ones such a measure that their common masses are enough for cool forming after the twisting the 5 commutator bars. The 5 commutator bar has a circular section hole on the side close to the shaft its depth overcomes the half diameter of the hole, its width is less then the circumference divided by the number of core 's slots which assures a certain air gap between the bars. The 5 bars are formed separately or in same time all by itself known method and tools. The 7 isolating ring has a hole for fixing to the 8 shaft and for fixing the bars shaped surfaces to the bar's hole and 14 elements for isolating the bars from each other. The 5 bars are assembled in a non drawn tool with the 7 isolating body the 8 shaft and the 1 core. Second example

In the further examples the core and windings and the commutator bars are not shown in their final positions.

We form of the 4 inner wire the 9 half-bar by itself processing method and of the 3 outer wire the 11 other half-bar. On the 9 half-bar's outer side related to the 8 shaft there is a gorge for encapsulating the 10 isolating ring. Positioning on a less radius related to the final one we pull the isolating ring on them. We put the 9 half-bars into the ultrasonic welding tooling to weld over the isolating ring the 11 half-bar formed of 3 outer wire to the 9 half-bar. The half-bars can joined to each other by any other method that produces sufficient mechanical and as well electrical connection. After putting out the 9 half-bar kept in range by the isolating ring, we press with the interference to the 13 isolating body that is fixed on the 8 shaft. This way the 10 isolating ring has a stress which firmly fixes the welded half-bars axially as well as radial direction. The 10 isolating ring can be made of plastic reinforced by glass fiber or made of steel coated by isolating material. Third example

Of the 4 outer wire that is related closer to the 8 shaft is formed the 9/1 and 9/2 half- bars which are continuously belong to each other and the outer wire, but have different shape on their sections. Of the 3 inner wire is formed the 11 half-bar. This half-bar has a gorge on its outer surface related to the shaft for encapsulating the 10 isolating ring. The 9/1 half-bars are situated into the fillisters of the 13 isolating body. The 9/1 half-bars support the 11 half-bars. In this status of the 9/1 and 11 half-bars fix them to each other the stressed 10 isolating ring. To this pre assembled unit is bended the 9/2 half-bar, bended with 180° from its original position. The cylindrical running surface of the commutator is the bended 9/2 half-bar's surface that is free from the 12 pressing ring. To obtain the exact position of the half- bars and other parts of the commutator it is recommended to use different positioning and fixing elements. The 1 armature's core with the winding is situated to closer side of the 12 pressing ring.

The invention is not confined to the examples. For example the 12 pressing ring can be made of steel coated the inner surface with isolating material. Similarly the 9 and 11 bar-half can be adjoined not only by ultrasonic welding but any other method that can obtain sufficient mechanical and electrical connection without damaging the 10 isolating ring. The method can be heat protection or isolating ring made of ceramic. These examples can be used for face commutators as well as the cylindrical ones which are shown.

All of the examples reflect the most important propriety concept of the invention which is that the commutator bars are made of the wiring ends, they are in monolithic relation to each other, otherwise all of the mechanical forming happen separately from the isolating material so it can not damage neither mechanically nor electrically. Because of this fact the armature's processing on base the hereby invention is not only simplier but also cheaper and more reliable because of the non required connection process of the armature winding ends to the commutator bars by soldering or welding, and the armature's life period become longer and its operation more reliable.

Claims

Claims:

1. Commutator for rotating electric machines characterised by the bars of the commutator are fully or partly created from the one of the armature's winding end at least on the connected surface to the brush and the commutator bars are monolithic with the armature's wire.

2. Commutator as claimed in claim 1 , wherein each commutator bar fully or partly consist of the winding ends connected by the armature's wiring schema.

3. Commutator bars as claimed in claim 1 and 2 wherein are fix to the 7 isolating body with interference and their assembling process happens in the ready solid status of the isolating body.

4. commutator as claimed in 1 , 2 and 3 claims wherein the commutator's bar- half created from the wiring ends are joined to each other either with melting or ultrasonic welding and the half-bars that are closer to the shaft are fixed on the 7 isolating body by the 10 isolating ring.

5. Commutator as claimed in 1 , 2 and 3 wherein the 9 and 11 formed bar- halfs are created from 2 and 3 wire's ends are fixed to each other with the 10 isolating ring and the 9/2 elongated part of the 9/1 bar-half is bent on the 11 other half-bar and this status is fixed by the 12 pressing ring.

6. Armatures for electric rotating machines claimed in 1, 2 and/or their commutator bars that can characterise by one of the 1-5 claim.