EP0821838B1 - Collector manufacturing process - Google Patents

Abstract

PCT No. PCT/EP96/01607 Sec. 371 Date Oct. 21, 1997 Sec. 102(e) Date Oct. 21, 1997 PCT Filed Apr. 17, 1996 PCT Pub. No. WO96/33534 PCT Pub. Date Oct. 24, 1996A process for manufacturing collectors, in particular flat collectors for electric machines. The individual connection elements (2) are at first directly shaped by crowding in a substantially non-machined raw conductive material (1) with their final contour and size and in their final ductile state. For that purpose, a warm forming process is used. The raw material (1) is warmed before the connection elements (2) are formed so that it does not significantly consolidate while the connection elements (2) are formed by crowding, and forming is then carried out in the warm state. In addition, a pot-shaped blank (3) may be shaped, preferably in a cold forming step, for example with inner shaped anchoring elements (6) for an insulating lining. Recesses (9) may be shaped by crowding on the cylindrical envelope (4) of the pot-shaped blank (3). These recesses are associated to the segment divisions and extend almost down to the bottom (5) of the pot-shaped blank (3). In a subsequent forming step, outer anchoring elements (13) are formed on the cylindrical envelope (4), if required a central opening (14) is cut out in the bottom (5) and the previously shaped inner anchoring elements (6) are bent outwards in the radial direction.

Description

The invention is concerned with a method of manufacture a commutator, in particular a flat commutator, for electrical machines according to the preamble of claim 1.

DE 41 40 475 C2 describes a method for producing a Pressed plane commutator of the type mentioned above is known. This is from an essentially unprocessed raw material based on conductive material, which preferably is present in rod material, of which a starting body for example in the form of a round blank. Means Extrusion this base body into a cup-shaped Formed blank, which is an annular plan part and has an adjoining tubular jacket. in the In the course of the multi-stage forming, wreaths are arranged inner anchoring elements as well as outer anchoring elements molded to the later in the pot-shaped interior of the Blank molding compound to be used as an insulating compound serves to anchor reliably with the commutator. In one further work is carried out at the free end of the jacket of the pot-shaped blank a radially protruding outward Formed ring flange, namely by material displacement in the axial direction against the free end of the jacket there. In a further step, the flags are now in the shape of a flag trained connecting elements by punching out of the Preserved ring flange. With this punching process the outer anchoring elements are also split off. By punching the connecting elements out of the continuous previously formed ring flange at the free end of the jacket of the Blanks accumulate waste material that remains unused, in particular those left behind and punched free Connection elements only a small fraction of the total ring flange area ingest so that a relatively large amount of material this manufacture is lost.

Another difficulty is the fact that the various extrusion treatments and also during training of the ring flange inevitably through the forming one Material consolidation is effected so that the formed Connection elements less ductile or bendable than the starting raw material are. After the completion of the commutator but connecting wires are wound around these connecting elements and then the connectors are on the outside of the cylindrical jacket bent back. As a result of material embrittlement are therefore cracks in the usual production method occurred and these are generally to be feared. Also includes the known manufacturing process a variety of individual Deformation steps, including the economical production method such commutators suffer.

From US-A-3 812 576, the disadvantages and difficulties with which DE 41 40 475 C2 dealt with above can be overcome is a method of making a commutator for known electrical machines in which starting from a disc-shaped, conductive raw material a cylindrical part is produced, which has an open end with a radial outwardly projecting, continuous ring flange and one Has ground. Pressed parts are removed from the Inside of the cylindrical portion of the cylindrical part formed, which when filling the insulating material later prevent this on the ring flange or on the outer Adheres to the surface of the floor. Then the ring flange processed in such a way by punching that flag-shaped Connection elements of this remain, and the excluded Sections and the punched-out parts of the ring flange be removed.

Apart from the large number of individual work steps falls when punching out the flag-shaped connecting elements also waste material and through the individual forming processes there is a risk that in the end by Single, flag-shaped connecting elements obtained by punching Material hardening or embrittlement occur.

In contrast, the object of the invention is under Overcoming the difficulties outlined above Method for producing a commutator, in particular one To provide face commutators of the generic type, which is an economical and material-saving manufacture permitted, and in particular the connection elements after the formation are ductile or bendable and until implementation remain bendable during the bending process.

According to the invention, this is a method of manufacture a commutator, in particular a flat commutator, for electrical machines provided, which consists of an im essential raw raw material made of conductive material forming several, isolated from each other and Isolierstoff comprehensive segments with assigned, radially from the segments individually protruding connecting elements is, whereby the manufacturing process distinguishes that the raw material first for the formation of the individual connection elements with finished contour and size as well is formed with the finished ductile state.

In deviation from the previous manufacturing methods for commutators are thus in the inventive method starting from the raw material, first by forming the individual connecting elements formed by material displacement. It is essential here that these connection elements this forming process have their finished shape and size and in a ductile finished state, which up to final bending processing is retained. Through this direct shaping of the individual connection elements on the Raw material base bodies are thus subsequent processing operations, such as free cutting and the like, avoided since the connection elements thus formed already have their finished contour and - have size. Thus, the method according to the invention also falls no waste material because there is no continuous ring flange is formed, but only the individual flag-shaped Connection elements, which are in the radial direction on the outer edge protrude from the raw material body. In particular, on this way it can also be achieved that the connection elements are ductile or bendable because they are ahead of the subsequent ones Forming processes were formed and no deformation more exposed, which leads to material hardening or embrittlement. This way the inventive method a commutator economical and Made to save material.

According to a preferred procedure, the raw material before forming to form the connection elements in Dependence on the selected raw material or raw material heated in such a way that there is a notable strain hardening of the material avoid when designing the connection elements leaves. This allows the ductility of the formed Improve connection elements and their ductility depends essentially depends on the properties of the raw material.

According to a particularly preferred production method according to the Invention takes place the formation of the connection elements in the so heated state of the raw material, one such Treatment called warm presses, so that the raw material passed to the press immediately after heating and the shape of the connection elements while still warm he follows. The material can be formed if necessary Forging and / or at forging temperature. Preferably the connection elements are shaped in the warm or warm area.

One has been found to be useful for heating the raw material Temperature of about 150 ° C and higher, which of course depends on the raw material used. Especially at Copper and its alloys are the ones that occur here Temperatures are subject to large fluctuations and it can do not specify absolute temperature values for this. Conveniently the raw material is heated to a temperature in a range from about 300 to about 700 ° C.

An alternative manufacturing method to train the individual Connection elements with finished contour and size as well as with ductile Finished state is characterized in that the raw material annealed before forming to form the connecting elements is formed, the connection elements by cold forming be followed by another annealing treatment. In this way it can also be avoided, for example, that the connection elements after the formation by the Forming caused material hardening and embrittlement become less ductile. However, such a method of manufacture time consuming, since after the annealing treatments Cooling times must elapse.

Based on this state that the raw material is first to Training of the individual connection elements according to the preceding Description has been transformed, then takes place a cold forming, in which a pot-shaped blank with a essentially cylindrical shell and one essentially plan floor is formed. For this area of the commutator is material hardening for reasons of wear desired, which one in a targeted manner, especially in planning Bottom area of the pot-shaped blank through the Receives cold forming treatment.

Cold forming also creates rings the inner surface of the bottom is essentially axial, molded internal anchoring elements for the insulating material filling. The segment division is expediently assigned Recesses, starting from the free edge of the jacket, through Material displacement formed by cold forming. This Recesses extend close to the inner surface of the bottom of the pot-shaped blanks. Preferably, the clear width of the Recess, starting from the free edge of the jacket, in the direction of the soil are getting smaller, and in particular the are through Material displacement trained recesses V-shaped. Of the The "tip area" of the respective V-shaped recess becomes preferably formed by a short straight section. The The number of these recesses corresponds to the number of segments of the commutator and they are assigned to the respective divisions. Because these recesses are close to the inner surface of the floor of the pot-shaped blank, you get to the next one Cutting processing to the department of the individual Segments from the flat outer surface of the floor depths of cut as small as possible, so that on the one hand the filled insulation material not cut deep must be, and on the other hand the cutting can be carried out quickly and easily.

On the inner surface of the floor can be narrow, radially running Wells are formed, which of the "Top area" of the respective recesses and go out extend to the center of the floor area. Here you can reduce the depth of cut even further and is even less than the base material thickness of the floor. Furthermore, the Reliefs a reliable guide when cutting and Sawing to divide and separate the segments of the Commutators.

According to a preferred way of producing a commutator According to the invention, cold forming is used for training of the pot-shaped blank, to form the ring-shaped arranged inner anchoring elements and by Material displacement formed recesses and, if necessary to form the radial recesses in one Work step carried out. This makes one in particular economical production of such a commutator achieved because you have very short processing times for the Cold forming in the manufacturing process according to the invention Has.

Furthermore, in the method according to the invention, the jacket radially inward facing outer anchoring elements for the Insulating material filling formed by cold forming.

In case of an unperforated raw material made of conductive Material in the manufacture of the commutator according to the invention goes out, is for the rotor shaft of the electrical machine in the A central opening is punched out of the bottom of the pot-shaped blank. If you are from a perforated raw material or from one Bar material with a tubular cross-section and large Of course, this processing step can result in wall thickness omitted.

Furthermore, the inner anchoring elements become slight bent radially outwards to ensure the anchoring effect with the later filled insulation material and the insulation material filling improve.

According to a preferred embodiment of the invention Manufacturing processes are carried out for training purposes the radially inward facing anchoring elements, for punching out the central opening in the bottom of the pot-shaped blank and the bending of the inner anchoring elements radially outwards in one work step. Hereby can the manufacturing times for such Shorten the commutator considerably, since you can see overall the method according to the invention, for example in essentially only three transformation steps starting from Raw material up to the finished commutator without insulating material filling and post-treatment or post-processing is required.

All other processing and treatments, such as insertion the insulating material filling, if necessary tinning of the base body and severing the segments by cutting along the Segment divisions and attachment of lead wires to the Connection elements and bending the same can then on be carried out in the usual way. The bending process for the Connection elements is thanks to the manufacturing method according to the invention significantly simplified and cracking due to material embrittlement can be avoided because the connection elements in the ductile condition without material hardening through the forming processes available. Furthermore, an undisturbed fiber course is through the forming process, so that the commutator high can withstand dynamic stresses, in particular occur in motor vehicles.

The manufacturing method according to the invention is for manufacturing of commutators of different designs and Types suitable, and the invention is not to manufacture limited by face commutators. Essential to the Manufacturing of all these types of commutators is however the fact that the connection elements on the one hand be formed that there is no waste material, and that on the other hand, these connection elements with finished contour and size and with a ductile finished state right at the beginning of the manufacturing process are formed by material displacement. This material displacement takes place, seen from the raw material base for the formation of the connection elements in the direction outward. Depending on the design of the commutator can of course use the anchoring elements for the insulating material filling be shaped in a correspondingly changed manner without that the protective concept is abandoned according to the invention, according to which the shape of the connection elements directly from the Raw material through material displacement to the finished contour and - size and finished with ductile finished.

Fig. 1

eine perspektivische Ansicht eines RohmaterialGrundkörpers,

Fig. 2

eine perspektivische Ansicht im Zustand mit den durch Umformung und Materialverdrängung erhaltenen, einzelnen Anschlußelementen,

Fig. 3

eine perspektivische Ansicht zur Verdeutlichung eines topfförmigen Rohlings mit inneren Verankerungselementen, und

Fig. 4

eine perspektivische Ansicht eines topfförmigen Rohlings, bei welchem eine zentrale Öffnung vorgesehen ist und äußere Verankerungselemente zusätzlich ausgebildet sind.

The invention is explained in more detail below with the aid of a preferred embodiment with reference to the attached drawing, which, however, does not represent any limitation. The drawing shows:

Fig. 1

a perspective view of a raw material base body,

Fig. 2

3 shows a perspective view in the state with the individual connecting elements obtained by forming and material displacement,

Fig. 3

a perspective view to illustrate a cup-shaped blank with inner anchoring elements, and

Fig. 4

a perspective view of a pot-shaped blank, in which a central opening is provided and outer anchoring elements are additionally formed.

The example according to the invention is used only in one example Process in connection with the production of a basic body explained for a flat commutator. In the same or Similarly, commutators can of course also be used other designs are manufactured and molded.

In Figure 1 is an example of a substantially unedited one Raw material 1 shown. This raw material 1 is exemplary represented as a flat, solid disc, which by a round bar material is sheared off and formed. If necessary, deviations from FIG. 1 cannot be specified raw material shown are taken as starting material, which is designed for example as an annular disc and already has a prefabricated central opening 14 'like this is indicated in Figure 1 with a broken line. The basic body of raw material 1 can alternatively be stamped out a strip material with or without a hole can be obtained. If a thick-walled tube-rod material is used as the starting material takes, as the raw material 1, the disc in the form of a round blank available. All of these raw materials are raw 1 can be used in the method according to the invention and it will only as an example of a solid material in the form of a Disk out for explanation below. Possibly can also from such a solid material disc Ronde can be obtained by having a central opening punched out as a kind of preprocessing step (not shown).

Starting from the raw material 1 according to FIG. 1, then first formed by forming individual connecting elements 2, which for example, are flag-shaped according to FIG. 2. These connection elements 2 protrude radially over the peripheral edge of the Raw material 1 according to Figure 1 as individual connection elements 2 before and these are shaped in such a way that, as in FIG is shown, have their finished contour and size. Also have these connection elements 2 their ductile finished state. Specifically According to a preferred method of production, the raw material 1 before the formation of the connection elements 2 depending on the material properties heated so that a notable material forming hardening can be avoided. In this heated state then the connection elements 2 with the finished and final state preferably shaped. Such Forming can be referred to as semi-hot presses, for example become. Of course there is also a shape in the normal range possible. In the formation of the connection elements 2 that Material of the raw material 1 preferably towards the outside displaced while still warm, and the corresponding Molding tools that are used for this have assigned rooms, which the finished contour and size of the Specify and limit connection elements 2.

Because the temperatures required for this depend on the properties of the conductive material used for the Raw material 1, in particular for example of copper alloys, depend, only preferred ranges can be specified. It has been shown that heating to a temperature of about 150 ° C is appropriate. This temperature can of course, be higher. In a preferred manner, a Temperature range from about 300 to about 700 ° C result.

As an alternative to semi-hot pressing, there is also cold forming the connection elements 2 into consideration. In this case, for example the raw material 1 are annealed, and after The connecting elements 2 according to FIG. 2 are then cooled with Finished contour and size shaped. To the desired ductility to achieve the connecting elements 2, these can be used individually or the entire base body shown in FIG. 2 again be annealed.

FIG. 3 shows a commutator blank 3, which one by cold forming starting from the body according to FIG. 2 receives. This blank 3 is cup-shaped and has a substantially cylindrical shell 4 and one in essential plan floor 5. At the same time during molding of the pot-shaped blank 3 become internal anchoring elements 6 formed, which is ring-shaped on an inner surface 7 of the Bottom 5 of the pot-shaped blank 3 are arranged. How shown, these inner anchoring elements 6 run in essentially axially related to the blank 3 and stand jagged from the inner surface 7 of the bottom 5 at a distance Way forward.

As shown, the forming process is based on the figure 2 to the pot-shaped blank 3 according to FIG. 3, preferably in a single forming step. Of course they can Forming processes, if necessary, also one after the other be performed.

If necessary, starting with the forming treatment from Figure 2 to Figure 3 through a number of recesses 9 Material displacement are trained. The number of recesses 9 corresponds to the number of segment divisions and at the embodiment shown are eight such recesses 9 available. According to the preferred shown Embodiment each recess 9 goes from a free edge 10 of the cylindrical shell 4 and extends close to Bottom 5 of the pot-shaped blank 3. Preferably, the clear width of each recess 9 starting from the free edge 10 down to floor 5. The recesses 9 are therefore V-shaped trained and expediently in the apex area a straight line segment. Starting from the vertex area each V-shaped recess 9 can be narrow, web-shaped trained and radially extending recesses 16 formed which are assigned to the segment division and are in Direction of the center of the bottom 5 on its inner surface 7 extend. The advantage of these recesses 9 and possibly the recesses 16 will be explained later. The shape of the recesses 9 and, if appropriate, the narrow, radially extending recesses 16 can with all other forming operations in one step be, so that you start from that shown in Figure 2 Body in one step that shown in Figure 3 receives cup-shaped blank 3 for the commutator.

In a next step, another forming process takes place to a base body 12 shown in Figure 4, in which it is an intermediate product made of a conductive material is involved in commutator manufacturing. This base body 12 has external anchoring elements obtained by cold working 13, which in the vicinity of the free edge 10 of the jacket 4th are formed radially jagged inward. At the same time, if according to a solid material disc a raw material 1 is assumed, a central one Opening 14 punched out in the bottom 5 of the pot-shaped blank 3 become. This central opening 14 is located radially in the base 5 within the ring-shaped arrangement of internal anchoring elements 6. Preferably in this treatment step also the inner anchoring elements 6 slightly radially bent outside to improve its anchoring effect.

Although in the example according to the invention based on the body shown in Figure 3 in one step Base body 12 as an intermediate product in the production of commutators can be reshaped and shaped, of course Edits can also be made one after the other. If you start from a raw material (not shown), which already has a central opening 14 ', can of course the punching process according to FIG. 4 is omitted. These the central opening 14 shown is then already present, which for the inclusion of a rotor shaft no closer electrical machine shown is determined.

Starting from this base body 12 according to Figure 4 made of conductive Material, which is exclusively through material forming has been received, the commutator can then completely be completed that one in the interior of the pot-shaped Filled and pressed 3 blank insulating material, which with Help the inner anchoring elements 6 and the outer Anchoring elements 13 reliably anchored to the base body 12 is. If necessary, tinning can be carried out become. Starting from the flat, continuous outer surface 15 the bottom 5 are then used to separate and subdivide the Segments introduced on the commutator cut, only one Depth of cut approximately the material thickness of the bottom 5 required is because the recesses 9 are already used to separate the segments on the segment dividing lines on the cylindrical jacket 4 have been formed. This simplifies the subsequent cutting processing in a noteworthy manner. If additionally the narrow, radially extending depressions 16 are formed, the depth of cut can be further reduce so that they are even smaller than the basic material thickness of the bottom is 5. In addition, a tour of cutting processing for segment division and separation can be achieved.

Such a commutator, not shown in more detail, is then used electrical lines on the preferably flag-shaped trained connecting elements 2, which for example around the connection elements in one or more turns be wrapped. Then the connection elements 2 in Direction to the outer surface of the cylindrical shell 4 bent back. This bending process can be done easily and make crack-free, since the connecting elements 2 thanks to the invention Manufacturing in a ductile or bendable Condition with undisturbed fiber orientation. Such a Completed commutator is then, for example, in a electrical machine installed.

Since these further processing steps, such as introducing the Insulation filling, cutting the segments, attaching the Lead wires and bending the connection elements 2, on this Area are common, they are only explained and not shown in detail. Furthermore, they are not the subject of Manufacturing method according to the invention.

Although above, the manufacture of an intermediate serving base body 12 for a commutator, especially for a flat commutator, has been explained, the after Invention of course also essential step in particular differently designed commutators in process engineering Aspects to be realized, according to which first from the Raw material 1 connecting elements 2 by material displacement which are already formed after the molding finished shape and size, and especially in ductile Finished state. All other forming operations can depend on the shape and Size of the commutator to be manufactured in a coordinated manner to get voted. It is also essential that the insulating material base body 12 to be filled exclusively by Forming from a raw material from conductive Material is manufactured, and that all of these forming operations yourself with the smallest possible number of work steps can be carried out, in a targeted manner, apart from the connection elements 2, which are used in cold forming caused material consolidation to increase the Strength of the base body 12 is used. At a The flat commutator should in particular be the outer surface 15 the bottom 5 to be resistant, for example on this the brushes of an electrical machine are running.

In particular, in the method according to the invention shape the connecting elements 2 in a material-saving manner, as they are directly shaped in the finished shape and size be without having an annular flange on the free edge 10 of the cylindrical shell 4 of the cup-shaped blank 3 required. Through this material reduction due to the avoidance of Waste material in the manufacture of the connection elements 2 the basic material costs to be used for the Production of such a commutator reduce the Economy of the production method according to the invention increase overall.

Reference list

1

Raw material

2nd

Connection elements

3rd

Blank according to Figure 3

4th

coat

5

Floor planner

6

Inner anchoring elements

7

Inner surface of the floor

9

Recess

10th

Free edge of the jacket

12th

Base body according to FIG. 4

13

External anchoring elements

14

Central opening

14 '

Central prefabricated opening in Figure 1

15

Outer surface of the floor 5

16

Narrow depressions

Claims (18)

1. Process for producing a commutator, in particular a flat commutator, for electric machines, which is produced from an essentially non-processed conductive raw material with formation of several segments insulated with respect to one another and comprising insulating material with assigned individual connecting elements (2) projecting radially from the segments, characterised in that the individual connecting elements (2) of final contour and size as well as having a ductile final state are initially formed directly from the raw material (1) by crowding.
2. Process according to claim 1, characterised in that before deformation to form the connecting elements (2), the raw material (1) is heated independently of the material to avoid considerable deforming material solidification.
3. Process according to claim 2, characterised in that the connecting elements (2) are formed in the heated state of the raw material (1).
4. Process according to claim 2 or 3, characterised in that the raw material (1) is heated to a temperature of about 150°C and higher.
5. Process according to claim 4, characterised in that the raw material (1) is heated to a temperature in a range from about 300 to about 700°C.
6. Process according to claim 1 or 2, characterised in that the raw material (1) is annealed before deformation to form the connecting elements (2), the connecting elements (2) are formed by cold forming and then annealed once again.
7. Process according to one of the preceding claims, characterised in that after forming the individual connecting elements (2) by cold forming, a pot-shaped blank (3) having an essentially cylindrical casing (4) and an essentially flat base (5) is formed.
8. Process according to claim 7, characterised in that inner anchoring elements (6) for the insulation filler which are arranged in a circle and extend essentially axially on the inner surface (7) of the base (5) are formed by cold forming.
9. Process according to claim 7 or 8, characterised in that recesses (9) assigned for segment division starting from the free edge (10) of the casing (4) are formed due to crowding as a result of cold forming.
10. Process according to claim 9, characterised in that the recesses (9) extend close to the inner surface (7) of the base (5) of the pot-shaped blank (3).
11. Process according to claim 9 or 10, characterised in that the inside width of each recess (9) starting from the free edge (10) of the casing (4) becomes smaller in the direction of the base (5).
12. Process according to claim 11, characterised in that each recess (9) is designed to be approximately V-shaped.
13. Process according to one of claims 9 to 12, characterised in that narrow depressions (16) assigned for segment division are formed on the inner surface (7) of the base (5) and extend radially in the direction of the central point of the base (5).
14. Process according to one of claims 7 to 13, characterised in that cold forming is carried out in one working step.
15. Process according to one of claims 7 to 14, characterised in that external anchoring elements (13) for the insulation filler pointing from the casing (4) radially inwards are formed by cold forming.
16. Process according to one of claims 7 to 15, characterised in that a central opening (14) is punched out in the base (5) of the pot-shaped blank (3) for the rotor shaft of the electric machines.
17. Process according to one of claims 7 to 16, characterised in that the inner anchoring elements (6) are bent slightly radially outwards.
18. Process according to one of claims 15 to 17, characterised in that the treatments are carried out in one working step.

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