HK1117943A - Flat commutator and method for producing a flat commutator - Google Patents

Description

Planar commutator and method for producing a planar commutator

Technical Field

The invention relates to a planar commutator, in particular a carbon planar plug-in commutator, and to a method for producing such a planar commutator.

Background

Such a flat commutator is used, for example, for fuel pumps. The electrically conductive connection segments, which are usually made of copper or contain copper, do not have the electrical resistance required for continuous operation in this medium. For this reason, several face segments are used for the face of the planar commutator, which have a higher electrical resistance than the medium surrounding the planar commutator.

Some such planar commutators are known, for example, from WO97/03486a 1. In this case, a carrier body forming a hub for a commutator is molded from an electrically insulating material onto a conductor blank forming the connecting segments. For this purpose, the conductor blank is inserted into a corresponding mold and is molded in the mold with a material forming the support. Subsequently, a carbon annular disk forming the running surface segments is soldered to the conductor blank and subsequently separated into the individual running surface segments. The planar commutator produced in this way meets high quality requirements, but the production method is therefore very complex and consequently expensive.

DE19926900a1 discloses a method for producing a flat commutator, in which the surfaces of the metal segment carrier exposed by the individual parts of the carrier are coated with an environmentally resistant, for example fire-resistant, layer.

A commutator according to the preamble of claim 1 is known from EP1363365a 1. Each connection segment has a connection portion for connecting one end of a coil winding and a contact portion for electrical connection with the running surface segment. After the insertion of the connecting segments into the carrier, the connecting portions are bent at right angles and parallel to the plane of the running surface. A carbon-containing disk is then attached to the curved connecting sections, the disk being separated by trimming dies and thus forming the running surface segments. The carbon-containing discs consist of two layers, which are connected to one another by cold extrusion. The first layer provided for each of the coupling segments comprises an adhesive. When applied to the connecting segments, the adhesive softens under the action of heat and the first layer flows under the action of the simultaneous pressure into the holes of the connecting segments and the support body and thus anchors the carbon-containing disks to the support body.

Disclosure of Invention

It is therefore an object of the present invention to provide a planar commutator and an associated production method which overcome the disadvantages of the prior art, in particular are inexpensive and also ensure a sufficient resistance of the finished commutator in a reaction-promoting (regenerative ö rderrendn) environment.

This object is achieved by the planar commutator defined in claim 1 by the method defined in the accompanying claims. Particular embodiments of the invention are defined in the dependent claims.

In contrast to so-called drum commutators, in planar commutators the running surface of the carbon brushes of the commutators is formed by a planar end surface. The construction of the planar commutator is therefore different from that of the drum commutator.

The flat commutator of the invention has a carrier body made of an electrically insulating material, for example a thermosetting plastic. On the carrier, a plurality of connection segments are provided, which are intended for connecting in each case at least one end of a coil winding of, for example, a rotor of an electric machine and are made of a material which conducts electricity well, for example copper or a copper alloy. In order to increase the resistance of the running surface of the commutator with respect to the medium surrounding the commutator, the commutator furthermore has a plurality of running surface segments which together form a planar running surface of the planar commutator, wherein the number of running surface segments generally corresponds to the number of connecting segments, in particular is identical thereto or is an integer fraction thereof or an integer multiple thereof.

According to the invention, the support body has openings into which the connection segments are inserted. One feature is that the support body is produced as a separate part before the insertion of the connecting segments in a mold which has openings for receiving the connecting segments. The support body can thereby be produced in a simplified manner with high dimensional accuracy, for example also by means of an injection molding method, in particular by injection molding around the connecting segments, which eliminates the need for complex production processes.

The support body is preferably designed in one piece and in particular has integrally formed thereon openings for the insertion of the connection segments, bearing surfaces for the prefabricated running surface segments and bearing surfaces for the connection of the parts of the segments to which the coil windings are connected. The connection segments are preferably also formed in one piece, in particular the connection segments form not only the contact surfaces of the segments facing the running surface but also the connection surfaces for the coil windings in one piece.

The insertion of the connecting segments into the support body ensures a plurality of advantages. This eliminates the need to produce a conductor blank which forms the connecting segments. Furthermore, it is no longer necessary to supply such a conductor blank to an injection molding machine for injection molding the support body.

It is also advantageous that the connecting segments are no longer entirely surrounded by the plastic material forming the carrier, so that the different coefficients of thermal expansion of the material of the connecting segments and the material of the carrier no longer cause thermally induced stresses.

The running surface segments are mechanically fixedly and electrically connected to the connecting segments. Such a connection may be achieved, for example, by soft solder, braze, or glue. The face segments can be fastened to the respective connecting segment or can be fastened to the connecting segments in a composite body, for example in the form of a disk or annular disk, and subsequently separated by means of a trimming die. The connection segments are mechanically fixed to the flat commutator by mechanically fixed connections to the working face segments.

The connecting segments can also already be fixed only by the clamping action of the bearing bodies, which can be brought about by an at least partial allowance of the bearing bodies relative to the connecting segments. In this case, the fastening of the connection segments to the carrier can also be improved by an additional connection device, for example by an adhesive. In any case, the fastening of the segments to the carrier body is further improved in the direction of stresses during the operation of the planar commutator anyway by the connection of the running surface segments to the connecting segments.

The running surface segments have an overhang relative to the connecting segments, in particular relative to the end of the connecting segments facing the running surface segments, which overhang extends obliquely or transversely to the insertion direction, by means of which the composite body formed by the running surface segments and the connecting segments is anchored to the carrier. Thereby preventing movement of the composite in the direction of insertion.

The excess can also be formed at least partially by a connecting device, for example a solder, which connects the running surface segments to the connecting segments. Preferably, the running surface segments rest at least partially on the support body in the region of the excess, so that the support body itself forms an axially fixed support for the connecting segments.

The openings in the carrier body for receiving the connection segments extend at least partially parallel to an axis of the carrier body, preferably the openings extend parallel to a longitudinal axis of the carrier body, which preferably coincides with the axis of rotation of the planar commutator. The openings in the carrier body are open at least partially to the circumferential surface of the planar commutator, in particular in the part of the connecting segments which forms a preferably radially projecting connecting device for connecting the coil windings. In a further embodiment, the openings for receiving the connection segments extend in a radial or tangential direction with respect to the support body.

In the region of the ends of the connecting segments facing the running surface segments, the openings in the carrier have an enlargement. The enlargement preferably forms a receiving space for a connecting device, for example solder or adhesive, for connecting the segments to the face segments. After the age hardening, the connecting device preferably already forms an anchorage of the connecting segments on the carrier, in particular in combination with the associated running surface segments.

This applies in particular when the connection device flares in the region of the transition from the connection segment to the associated running surface segment due to effective surface tension, as is the case, for example, in soldered and glued connections. This also reliably prevents the medium surrounding the planar commutator from entering the region of the connection segments and thus protects the connection segments from corrosion.

In this connection, it is particularly advantageous if the connecting segments, in the inserted state, project with their ends facing the running surface segments into the region of the enlargement. In this case, the coupling means can act not only axially on the coupling segments, but can also engage these coupling segments at least partially circumferentially, thereby improving the engagement. The connecting device itself can thus form a tensioning anchor and prevent the connecting segments from moving axially.

Each connecting sector has a top and a bottom, which are connected to each other via a connecting portion. The associated opening in the support body has at least partially a margin, for example, such that the part of the support body lying between the top and the bottom is under compressive stress and/or the connecting part of the connecting segments is under tensile stress, depending on the dimensioning of the connecting segments. In this case, it is particularly advantageous if the faces of the head and the foot which lie opposite one another and which bear against the carrier form an angle of less than 90 °, since in this case the stresses in the carrier which occur as a result of the clamping of the connecting segments, in particular these stresses, which extend substantially in the radial direction relative to the longitudinal axis of the flat commutator, are compensated to a considerable extent, and therefore the flat commutator has a stable carrier even under high stress in continuous operation.

In this case, the connection segments are formed as identical parts, in particular as stamped or forged parts, or in the simplest case by cutting to length a corresponding profile. With regard to the adaptation of the geometry of the connection segments to the associated openings in the carrier body, it is particularly advantageous that a fine adaptation of the dimensions of the connection segments can be produced with little effort by adjusting the punching tool. The requirements on the dimensional accuracy of the support body are therefore reduced, which considerably simplifies the production method thereof.

Each connecting segment has a coating at least in the region of the connection to the running surface segment. The material of the coating is preferably adapted to the material of the connecting device, for example, the connecting segments are coated with tin or a material corresponding to a solder layer, generally over the entire surface, at least in the region of the connection with the running surface segments in the case of soldering.

The running surface segments consist of a material which has a higher electrical resistance than the connecting segments with respect to the medium surrounding the planar commutator. The material of the working surface segment is preferably carbon-containing, wherein not only so-called soft fire carbon (Weichbrandkohle) but also hard fire carbon (Hartbrandkohle) can be used. Preferably, each running surface segment has a coating on its part facing the connecting segment anyway, by means of which the connection is further improved.

The invention also relates to a method for producing a flat commutator, wherein the carrier body is produced separately from an electrically insulating material, and the connecting segments inserted into the openings of the carrier body are likewise produced separately. The face segments forming the face of the flat commutator are then fixed. In this case, the running surface segments can be already separated and fixed individually to the associated connecting segment, or can be fixed in a composite body, for example in the form of an annular disk, to the connecting segments and subsequently separated by means of a trimming die.

Drawings

Further advantages, features and details of the invention emerge from the dependent claims and the following description which describes several embodiments in detail with reference to the drawings. The features mentioned in the claims and in the description may in each case be essential per se or in any combination.

Fig. 1 is a cross-sectional view of a planar commutator known from the prior art;

FIG. 2 is a cross-sectional view of a planar commutator of the present invention;

FIG. 3 is a top plan view of the planar commutator;

FIG. 4 is a side view of the planar commutator of the present invention;

FIG. 5 is a cross-sectional view of a first embodiment of a connection between a connector segment and a running surface segment;

FIG. 6 is a cross-sectional view of a second embodiment of a connection between a connector segment and a running surface segment;

FIG. 7 is a cross-sectional view of a third embodiment of a connection between a connector segment and a running surface segment;

FIG. 8 is a perspective view of a second embodiment of the support body;

FIG. 9 is a top view of a particular embodiment of a face segment;

FIG. 10 is a cross-sectional view taken along line X-X in FIG. 9;

figure 11 is a side view of a second embodiment of the planar commutator;

figure 12 is a top view of the planar commutator of figure 11;

figure 13 a side view of the planar commutator of figure 11 in an assembled state;

figure 14 is a top plan view of the planar commutator of figure 13; and

fig. 15 is a view of another embodiment of a support body 502.

Detailed Description

Fig. 1 shows a cross-sectional view of a flat commutator known from the prior art. The planar commutator 1 has a carrier body 2 made of an electrically insulating material. The support body 2 has a longitudinal axis 4, which also coincides with the axis of rotation of the planar commutator 1. In particular, the planar commutator 1 can be axially symmetrical to the longitudinal axis 4. The flat commutator 1, in particular the carrier body 2, forms a bore 6 in the region of the longitudinal axis 4 for the passage of a shaft of an electric machine.

The carrier 2 is formed on connection segments 8 which have a bent hook 10 on the radial outside for connecting at least one end of a coil winding in each case. The running surface 14 of the planar commutator 1 is formed by the running surface segments 12, which are connected mechanically fixedly and electrically to the connecting segments 8. The entire surface segments 12, which are preferably arranged uniformly distributed around the longitudinal axis 4 along a circle, form the planar surface 14 of the planar commutator 1. Radially on the outside, each coupling segment 8 forms a circumferential surface 16 from which the hooks 10 are bent. Further details of the planar commutator 1 are given in WO97/03486A 1.

Fig. 2 shows a cross-sectional view of a planar commutator according to the invention, which is shown in cross-section II-II in fig. 1. The connector segment 108 has a top portion 108a and a bottom portion 108c, which are connected to each other via a connecting portion 108 b. Fig. 2 shows the region of a (not shown) running surface segment, which approximately corresponds in its contour to the transverse surface of the carrier 102. Support body 102 has a plurality of openings 118 arranged in a regularly distributed manner along the circumference, into which connector segments 108 can be inserted. Preferably in a direction parallel to the longitudinal axis of the flat commutator 101, which extends perpendicularly to the drawing plane of fig. 2.

The opening 118 has a margin in the circumferential direction in the region of the top 108 a. This reliably prevents possible undersizing of the opening 118, which could introduce compressive stresses extending in the circumferential direction into the support body 102, which could lead to permanent dimensional stability problems with respect to the support body 102, as a result of manufacturing tolerances. Correspondingly, the opening 118 is in the region of the base 108 c; the opening 118 here also has a margin with respect to the size of the base 108c, in particular in the circumferential direction.

The opening 118 also has a margin with respect to its radial extent in the section between the bearing surface of the top part 108a for the region directed radially inwards and the bearing surface of the bottom part 108c for the region directed radially outwards with respect to the radial extent of the connecting part 108b, so that in this region the connecting segments 108 bear on the bearing surfaces formed by the opening 118 and in particular on those surfaces which effect the force transmission indicated by the arrow 120 in fig. 2.

By means of this margin of the opening 118, compressive stresses are introduced into the support body 102 in the region of the connecting section 108 b. The reason for these compressive stresses is tensile stresses in the connecting portion 108b, which extends less in the circumferential direction than the respective extensions of the top portion 108a and the bottom portion 108 c. This results in elastic elongation of the connecting portion 108b in the radial direction. The connector segments 108 also act as a force reservoir. In this case, it is still preferably stretched within the elastic limit of the connecting segment 108, for example between 5 and 50 μm. In addition, the opening 118 has a margin in the circumferential direction in the region of the connecting portion 108b, so that no pressure is introduced into the molded body 102 in the circumferential direction at this location either.

The angle 122 formed by the mutually facing end faces of the radially outer region of the bottom 108c and the radially inner region of the top 108a is less than 90 °, preferably between 30 ° and 60 °, in particular about 50 °, and in the illustrated embodiment between 4 ° and 30 °, in particular about 15 °. By means of this acute angle, it is ensured that the pressure forces introduced from the connecting segments 108 into the supporting body 102 due to the elongation of the connecting sections 108b are substantially balanced with one another, in particular a negligibly small resulting pressure force component in the circumferential direction is maintained.

In the planar commutator 101 according to the invention, the connection segments 108 and the carrier 102 are therefore connected substantially stress-neutral. The forces occurring during insertion, which already result in effective clamping and thus fixing of the connector segments 108 in the carrier 102, cancel each other out in an advantageous manner. In particular, no forces acting in the circumferential direction and/or radially outward direction are maintained, so that the flat commutator 101 can maintain its form stability permanently and reliably even under difficult operating conditions, for example elevated temperatures.

This is preferably also achieved in that a part of the connecting segment 108 is always under tensile stress and acts as a spring-elastically deformable element. The connecting segments 108 are preferably inserted into the carrier 102 in the axial direction, wherein insertion is possible substantially from both end faces of the carrier 102. But is preferably inserted in many cases from the side of support body 102 remote from running surface segment 112. The shaping of the coupling segments 108 enables the coupling segments 108 to be automatically centered in the support body 102, so that the feeding and insertion of the coupling segments 108 can be easily automated.

It is also possible to insert the connector segments 108 into a stop, in particular a backseat, which is positionable relative to the carrier 102 during insertion. In this case, in order to anchor the connecting segments 108 to the carrier 102, it is advantageous if the stop is designed, for example, in the form of a pin and contacts a central region of the base 108c and there expands the base 108 by the insertion or pressing force during insertion.

In the region of contour 124 indicated by dashed lines in fig. 2, support body 102 forms an enlargement near the end of connecting segment 108 facing working segment 112, which enlargement can be used to receive a connecting device for connecting the connection between segment 108 and working segment 112.

Fig. 3 shows a plan view of the flat commutator 101, in particular of the carrier 102, which corresponds to fig. 2 in this respect, except that in the three o' clock position a connecting segment 108 is inserted into the opening 118. The remaining eight openings 118 in total are still not equipped with connecting segments in the illustrated state of the planar commutator 101. Again, the respective running surface segment 112 is not yet provided, but its contour is indicated by the dashed line 126. The top 108a with its radially outer contour follows the outer contour of the carrier 102 and thus partially forms a circumferential surface 116 of the planar commutator 101 which is thus flush.

Fig. 4 shows a side view of a planar commutator 101 according to the invention, with a front view in the lower half and a partial cross-sectional view in the upper half. The connecting segments 108 shown in the front view in the top half are inserted clampingly into the carrier 102. In the illustrated state, the top part 108a forms an integral plug or plate connection 108d for connecting at least one coil winding. Instead of the plug-in or plate connection 108d shown, it is also possible to bend the head 108a in this region in a hook-like manner (see fig. 1), or to have an insulating cross/clamp connection which cuts through the coil winding, or to have a welding head for soldering the coil winding. For the possible bending and fixing of the coil windings, it is advantageous if the connection segments 108 are already sufficiently firmly connected to the carrier 102 in the inserted state shown.

In the region of the end of the connecting segment 108 facing the face segment 112, the opening 118 in the carrier 102 has a first enlargement 124 and a second enlargement 128. The second enlargement 128 is also used here for the positive-locking reception of the face segments 112 and can also be, for example, an annular second enlargement 128 if the face segments 112 are present in a composite body, for example in the form of an annular disk.

In contrast, the first enlargement 124 is preferably provided separately for the respective connecting segment 108 and can be of circular design, for example. The space radially defined by first enlarged portion 124 may form a receiving space for a connecting device connecting sector 108 to face sector 112. In this respect, it is particularly advantageous if the connecting segment 108 projects in the axial direction, i.e. in a direction parallel to the longitudinal axis 104, with its end facing the running surface segment 112 into the region of the first enlarged portion 124. In this case, the connecting device can not only bear against the axial end faces of the connecting segments 108 over a large surface area, but can also overlap the connecting segments in a cover-like manner and also produce an additional seal between the connecting segments 108 and the support body 102. Preferably, the connection segment 108 has a coating at least at its end facing the running surface segment, which improves the mechanical and/or electrical contact.

Due to the radial extension of the running surface segments 112 relative to the connecting segments 108, this arrangement provides a secure fastening, in particular with respect to axial forces, to the supporting body 102 in an anchored manner after connection. The fastening is also improved in that the running surface segments 112 are at least partially supported, preferably flat, on the carrier 102.

The individual running surface segments can be multi-layered, in particular existing as multi-layered disks before the segment is formed. The multi-layer disk can have a carbon or carbon-containing layer forming the working surface and a further layer facing the connecting segments, which has at least one metallic component, for example copper, tin, brass or alloys thereof. The further layer serves in particular to improve the electrical and/or mechanical connection to the connection segments. The multilayer disc can be manufactured by a sintering process. Alternatively, the coating of the disk can also be carried out after the shaping process.

Fig. 5 shows a cross-sectional view of a first embodiment of a connection between connection segment 108 and face segment 112. This first embodiment is further characterized in that the coupling segments 108 are pressed against a stop, a support, a pin, etc. during insertion into the bearing body 102 in such a way that a particularly radial extension into the first enlargement 124 is produced, which already ensures a reliable axial anchoring of the coupling segments 108 in the bearing body 102, in particular by the engagement of the coupling segments with the undercut formed by the first enlargement 124.

The anchoring is further enhanced by the mechanically fixed and electrically conductive connection of the connection segment 108 to the running surface segment 112, which is realized in the first exemplary embodiment shown by means of an electrically conductive adhesive layer 130. In this case, the glue layer 130 not only bears against the end faces of the connection segments 108 and the corresponding end faces of the running surface segments 112, but also fills the region of the first enlargement 124 in the radial direction, so that a sealing and, in particular, a complete covering of the connection segments 108 is ensured by the glue layer 130. It is also possible to glue the connecting segments 108 themselves to the carrier 102.

Fig. 6 shows a second embodiment of the connection between the connection segment 108 and the face segment 112. A first difference from the first exemplary embodiment is the type of connection layer, wherein the second exemplary embodiment relates to a solder layer which, due to the applied surface tension, has a flared enlargement in the direction of the face segment 112 and in this way and in particular without the need for a widening of the connection segment 108, ensures a radial engagement in the region of the first enlargement 124 and thus a tensioning anchor with respect to the axial displaceability of the connection segment 108.

Another feature of the second exemplary embodiment is the manner in which the end of the support body 102 on the end side is formed. The support body narrows the second enlargement 128 at the end, for example by means of a radially outwardly disposed first lug 134 directed radially inwards and/or by means of a radially inwardly disposed second lug 136 directed radially outwards. The associated running surface segment 112 is in each case designed in a stepped manner and engages with its end facing the connection segment 108 behind the first and/or second lug 134, 136 of the second enlargement 128. The corresponding shape of the face segments 112 can either already be provided during the production of the molding or, for example, by trial turning (Andrehen) of an annular disk of this type if the face segments 112 are provided as a composite in the form of an annular disk.

By means of a matching shaping of the supporting body 102 and the running surface segments 112, it is possible to clamp the running surface segments 112 into the second enlarged portion 128, i.e. to fix them in a spring-locking manner on the supporting body 102. In the event of a corresponding, particularly axial, extension of the connection segments 108 into the region of the second extensions 128 and/or in the event of a corresponding, particularly axial, extension of the running surface segments 112 into the region of the first extensions 124, it is also possible to provide a mechanically sufficiently strong and sufficiently electrically conductive connection between the running surface segments 112 and the connection segments 108 solely by the locking fixation of the running surface segments 112 on the carrier 102. The locking fastening of the running surface segments 112 on the carrier 102 offers the advantage of a pre-fastening which ensures that the running surface segments 112 remain in the correct position relative to the associated connecting segment 108 even during subsequent gluing or soldering. Furthermore, by means of the locking fastening, the running surface segments 112 can also be held on the carrier with a particularly planar bearing.

In addition to the solder layer 132 shown in fig. 6, an additional sealing device, for example also a glue layer, can be inserted into the annular gap formed between the running surface segment 112 and the support body 102 in order to prevent aggressive media from entering these regions.

Fig. 7 shows a third embodiment of the connection between the connection segment 108 and the face segment 112. A first difference with respect to the two other embodiments is that the connecting layer 138 between the connecting segment 108 and the running surface segment 112 substantially completely fills the space of the first enlarged portion 124 and thus also forms an absolutely reliable seal of the bearing body 102 with respect to the connecting segment 108.

A further feature is that the bearing body 102, at its axial end in the region of the second enlargement 128, is again provided with a reduction, while forming annular or partially annular, optionally also only point-shaped lugs 134, 136, which may even be identical in terms of their dimensions to the second embodiment of fig. 6, but the dimensions of the running surface segment 112 are smaller than the inner width of the second enlargement 128 defined by the two lugs 134, 136. Thus, insertion of face segment 112 into second enlarged portion 128 does not result in clamping, but rather allows for loose insertion of face segment 112.

Of course, if the annular gap formed between the running surface segment 112 and the supporting body 102 is now filled, for example, with an age-hardenable substance, in particular a cement, a preferably annular fixing body 140 is thus obtained which, on account of its shape and on account of the cooperation with the contour of the supporting body 102, in the embodiment of fig. 7 with the first and/or second lugs 134, 136 and with the contour of the running surface segment 112, ensures a form-locking fixing of the running surface segment 112 on the supporting body 102.

In all three embodiments relating to the connection between the connection segment 108 and the running surface segment 112, the connection layers 130, 132, 138 form a rim, flare or an anchor element formed in any other way, which projects into the first enlarged portion 124, by means of which the connection segment 108 and thus also the running surface segment 112 are permanently fixed in the axial direction to the carrier body 102.

Fig. 8 shows a perspective view of a second embodiment of a support body 202. A first difference with respect to the supporting body 102 of the first embodiment is the substantially trapezoidal cross-sectional profile of the opening 218 for connecting the sectors. It follows that the first enlargement 224 is circular in plan view and covers the entire opening 218 in the second embodiment shown. First enlarged portion 224 again constitutes a storage space for a connecting device. The carrier 202 has a total of eight openings 218 for connecting the segments.

Second enlarged portion 228 is radially outwardly delimited by an outer ring 242 integral with supporting body 202 and radially inwardly delimited by an inner ring 244 integral with supporting body 202. The outer and inner rings 242, 244 are each formed from ring segments 242a, 242b, which are configured as respective running surface segments. Between adjacent ring segments 242a, 242b, in each case one groove 242c is provided which extends in the circumferential direction over the width of the tool for the segmental division of the respective working surface segment. In this way, the individual running surface segments, which are fastened to the carrier 202 or the associated connecting segments, for example as a composite of annular disks, can be separated by means of a trimming die without the outer and/or inner webs 242, 244 having to be cut off. The life of the cutting tool is thereby significantly increased. In addition, higher cutting speeds can be achieved, since it is no longer necessary to prevent the outer ring 242 and/or the inner ring 244 from breaking off by reducing the cutting speed.

Another feature of the support body 202 is that recesses for the segmental division of the annular disk, in particular radially extending recesses 248, which are aligned with corresponding recesses 242c in the outer ring 242 and the inner ring 244, are also provided in the support surface 246 of the support body 202. The depth of these recesses 248 is selected to ensure reliable separation of the annular discs without sawing in the support body. If these recesses 248 are also filled with a preferably electrically non-conductive adhesive, not only is an additional connection of the running surface segments to the support body 202 ensured, but also a fracture by the carbon-containing running surface segments during cutting is reliably prevented.

In particular, by using a support body 202 with an outer ring 242, a so-called soft fire carbon can also be used for the running surface segments, i.e. a plastic-bonded carbon (kunststoffgebunden Kohle), which can be selected to be matched to the exact composition of the associated commutator carbon brush. The carrier 202 has recesses 216a in the region of the circumferential surface 216, which are intended to receive the connection segments, in particular the parts of the connection segments intended for connection to the coil windings.

In the production of the flat commutator according to the invention, it is also possible, in particular after the insertion of the connection segments 108 into the bearing body 102, to introduce a preferably gas-tight, age-hardened and electrically conductive adhesive or another electrically conductive connection means in the region of the first enlargement 124 or over the entire surface in the region of the bearing surface 246, wherein in particular the first enlargement can be used in the form of a storage space for such a connection means. In order to improve the connection between the connection segment 108 and the running surface segment 112, the running surface segment 112 may also be coated, if necessary over the entire surface, for example tin-plated, at least on the surface facing the connection segment 108.

Fig. 9 shows a top view of a special embodiment of the running surface segment, namely in the form of a pre-segmented running surface disk 350. Fig. 10 shows a cross-sectional view taken along X-X of fig. 9.

One such face disk 350 may be divided into the respective face segments 312a, 312b by radial cutting sectors. In the present case, this fan-shaped division is achieved by the fact that the radial grooves 352 which have been formed during the forming of the running surface disk 350 combine with a reduced thickness of the running surface disk 350, the depth of the grooves 352, as shown in particular in the cross section in fig. 10, extending only to approximately half the thickness of the running surface disk 350. In particular, in the region of the running surface disk 350 remote from the support body, a connecting ring 354 remains, which connects the individual running surface segments 312a, 312b to one another. In the region of this connecting ring 354, actuating or tool surfaces 356 are provided, by means of which the running surface disk 350 can be supplied manually and automatically to the respective support body. The tool engagement surfaces 356 may be arranged distributed equally in the circumferential direction, in particular in the region of the respective running surface segments 312a, 312 b.

The running surface disk 350 forms projections 358 on the side facing the support body, the number and/or arrangement of which can be adapted to the arrangement of the running surface segments 312a, 312 b. In particular, these projections 358 can be adapted in their shape and configuration to the first enlargement 224 provided on the carrier 202, in particular can be inserted in a form-fitting manner therein. Simplified positioning of the face disk 350 on the support body 302 is thus ensured.

After the face disk 350 is attached to each of the attachment segments or supports 202, the face disk 350 may be turned on its exposed flat surface to the height indicated by the dashed line 360 in FIG. 10. The turning therefore proceeds until it enters the region of the respective recess 352, so that the respective running surface segment 312a, 312b is thereby separated. The use of a trimming die is therefore no longer necessary.

Fig. 11 shows a side view of a second exemplary embodiment of a planar commutator 401, in a still unassembled state. The carrier 402 is shown partly in cross section in the top half and in front view in the bottom half. In the lower half, the support body 402 is also shown to comprise inserted connecting segments 408.

A feature with respect to the embodiments described above is that the coupling sectors 408, in particular the top 408a thereof, preferably form integrally a flange 408e which forms at least partially the outer ring 242 formed by the support body 202 in the embodiment of fig. 8. This forms a radial outer protection for the running surface segments 412 and/or a bearing surface for positioning and aligning the running surface segments 412. Furthermore, the segments 408 can be additionally fixedly connected during the welding of the coil windings, in particular in the radial direction.

Another feature is that the connection segments 408 can be inserted from the side of the support body 402 facing the running surface segments 412. The insertion of the connecting segments 408 is carried out until they bear against the associated stop surface 462 of the carrier 402, which preferably forms a right angle with the longitudinal axis 404. Each face segment 412 has a coating, for example tin, copper or brass, on its face 464 facing the connection segment 408, with the aid of which a reliable mechanical and electrical connection to the connection segment 408 is ensured.

Fig. 12 shows a top view of the embodiment of fig. 11. Flange 408e is arcuate in plan view relative to longitudinal axis 404, the arc angle being about one-half of the arc angle of a face segment 412; the arc angle of the flange 408e is about 20 ° in the illustrated embodiment.

Fig. 13 shows a side view of the planar commutator 401 of fig. 11 in an assembled state. On the end face of the support body 402 facing the running surface segments 412, a recess 466 (fig. 11), which is circular in the exemplary embodiment shown, is provided and forms a storage space for connecting means for connecting the connecting segments 408 to the associated running surface segments 412. In the assembled state shown, flange 408e has an axial extension beyond the exposed plane of working face segment 412. By subsequent material removal, in particular by facing, the connecting segments 408, the running surface segments 412 and the carrier 402 are cut flat to form the running surfaces 414 of the flat commutator 401.

In contrast, in another alternative particular embodiment, the flange 408e does not extend beyond the exposed plane of the running surface segment 412 in the axial direction, but is set back relative to the plane or even relative to the running surface 414, in particular by one tenth or a few tenths of a millimeter relative to the running surface 414. No material of the flange 408e must be cut off when the respective face segment 412 is cut, thus simplifying processes such as facing. Typically each face segment 412 has a thickness of about 2.5mm in the disk composite, which is reduced to about 2mm by face turning. The axial length of the flange 408e is typically between 1.5 and 1.8 mm.

Of course, in this alternative embodiment, the support body 402 can also have ring segments 444a forming the inner ring, which have an axial extension beyond the exposed plane of the running surface segments 412. In particular, these ring segments have a bevel at their end at the end (see also fig. 15), by means of which the insertion of the running surface segments 412 is simplified. In particular, when the face sectors 412 are inserted in the disk complex, tilting of the disk on the flange 408e and thus the risk of damage to the disk are reliably prevented by the axial extension of the ring sectors 444 a.

Fig. 14 shows an associated plan view of the planar commutator 401 from fig. 13. The flange 408e forms a support ring for the respective running surface segment 412 on the radially outer side, whereas the support body 402 forms a support on the radially inner side by means of an integrally formed inner ring 444.

Fig. 15 shows another embodiment of a support body 502. The difference with the exemplary embodiment of fig. 8 is that the openings 518 are suitable for receiving connecting segments, the base of which has a shape which approximates a four-cornered kite (Drachenvierecks), the radially inner point of the four-cornered kite being flattened and the radially outer point of the four-cornered kite transitioning into the opening for the connecting section. The angle formed by the mutually facing faces connecting the radially outer region of the bottom and the radially inner region of the top of the sector (see fig. 2) is between 30 ° and 60 °, in particular about 50 °.

The first enlarged portion 524 matches the cross-sectional shape of the bottom of the connecting sector and is in particular pentagonal in the embodiment shown. In this case, the overlap of the first enlarged portion 524 with respect to the opening 518 in the circumferential direction is considerably small or even insignificant in the region of the boundary line of the radial extension of the cross-sectional shape of the opening 518. Whereas the other boundary lines with respect to the cross-sectional shape of the opening 518 form an excess amount of anchoring of the connecting segments in the supporting body 502, in particular on the radially inner and radially outer side.

The annular segment 544a forming the inner ring has a radially outwardly directed chamfer 544b at its end face, which simplifies the insertion of the running surface segment (not shown in fig. 15). In a corresponding manner, the ring segment 542a forming the outer ring may also have a radially inwardly directed bevel.

Claims (10)

1. Planar commutator (101) having a support body (102) made of an electrically insulating material, a plurality of connection segments (108) made of an electrically conductive material for connecting at least one end of a coil winding in each case, and a plurality of running surface segments (112) which form a running surface (14) of the planar commutator (101), wherein the running surface segments (112) are connected to the connection segments (108) in a mechanically fixed and electrically conductive manner, and the support body (102) and/or the connection segments (108) are formed in one piece, and wherein the support body (102) is prefabricated and has openings (118) into which the connection segments (108) are inserted, characterized in that the connection segments (108) are anchored to the support body (102) by means of a mechanically fixed connection to the running surface segments (112), the openings (118) in the bearing body (102) have an enlargement (124, 128) in the region of the end of the connecting segment (108) facing the running segment (112), the enlargement (124, 128) of the opening (118) forming a receiving space for a connecting device for connecting the connecting segment (108) to the running segment (112), and the connecting device forming an anchoring of the connecting segment (108) on the bearing body (102) after hardening.

2. A flat commutator (101) as claimed in claim 1, wherein the running surface segments (112) have an excess with respect to the connecting segments (108) in the radial direction and/or in the circumferential direction with respect to the axis of rotation of the flat commutator (101).

3. A planar commutator (101) as claimed in claim 2, wherein the running surface segments (112) at least partially rest on the carrier (102) in the region of the excess.

4. A planar commutator (101) as claimed in one of claims 1 to 3, characterized in that the supporting body (102) has at least partially a margin in the region of the openings (118) with respect to the inserted connecting segments (108).

5. A planar commutator (101) as claimed in one of claims 1 to 4, characterized in that the extension of the openings (118) in the carrier body (102) has at least one directional component parallel to the longitudinal axis (104) of the carrier body (102), in particular the openings (118) extend parallel to the longitudinal axis (104) of the carrier body (102).

6. A flat commutator (101) as claimed in claim 5, wherein the connecting segments (108) project with their ends facing the running surface segments (112) into the region of the enlargements (124, 128) in the inserted state.

7. A planar commutator (101) as claimed in any of claims 1 to 6, characterized in that the connecting segments (108) have a top (108a) and a bottom (108 c) which are connected to one another via a connecting section (108b), and the connecting section (108b) is elastically deformed by an at least partial allowance of the carrier body (102) in the region of the opening (118), and the connecting segments (108) are thus fixed clampingly on the carrier body (102).

8. The planar commutator (101) according to one of claims 1 to 7, wherein the connecting segments (108) have a coating at least in the region of the connection to the running surface segments (112).

9. Method for manufacturing a planar commutator (101), comprising the steps of:

producing a carrier body (102) from an electrically insulating material, wherein the carrier body (102) has openings (118) for receiving connection segments (108) made of an electrically conductive material for connecting at least one end of a coil winding in each case;

inserting the connecting segments (108) into openings (118) of the carrier body (102), wherein the openings in the carrier body (102) have an enlargement (124, 128) in the region of the end of the connecting segment (108) facing the running surface segment (112), and the enlargement (124, 128) of the opening (118) forms a receiving space for a connecting device for connecting the connecting segment (108) to the running surface segment (112);

the running surface segments (112) forming the running surfaces of the flat commutator (101) are fixed to the flat commutator (101) by means of a mechanically fixed and electrically conductive connection of the running surface segments (112) to the connecting segments (108) individually or in a composite body using connecting means which, after hardening, form an anchorage of the connecting segments (108) to the carrier body (102).

10. Method according to claim 9, characterized in that the connecting segments (108) pass through an enlargement in the radial direction and/or in the circumferential direction in the region of their end facing the running surface segments (112) when inserted into the carrier body (102) relative to a rotational axis of the flat commutator (101).