Universal electric motor.

State of the art

The invention relates to a universal electric motor according to the preamble of claim 1 and an automated method for its manufacture according to the preamble of claim 24th

The problem with a known specific for an electric hand tool universal motor of this type (DE-OS 37 31 079) for forward and reverse rotation, that is arranged to switch the Reversierschalters to a support ring two circumferentially each with a brush holder is electrically connected and radially resilient inwardly contact springs are provided, each having a Netzkontakt- and a field point of contact at their respective mutually adjacent, but separate from each other ends. The required contact pressure for a reliable contact is therefore acting merely generated in the radial direction by the force of the biasing springs, which springs are disposed within the Axialraums formed from the support ring, which also contains the carbon brushes, so that dirt and contact problems can not be excluded. The support ring is thereby rotatably mounted on a central axial projection of the facing end shield and learns through a security ring an axial position fixing.

To allow switching between forward and reverse rotation in a handheld power tool, it is also known (EP-PS 0,208,137) to form the means for shifting the sliding on the collector brushes as switches in the form of two mutually detachable support bodies of insulating material, wherein the two support body having interlocking collars which form a cavity in which the switching contact elements are arranged. In this known hand power tool and a largely automated assembly is possible because the two support bodies are in the form of a contact holder for the contacts for external connection of the machine tool or as a contact plate with the carbon brush holders and the contacting with the stator terminals by axial tabs. To enable the switching processes for the change of direction radially resilient contact bands are used in holding pockets of the contact plate, the contact is also, as with the electric hand tool of the initially considered DE-OS 37 31 079 takes place in the radial direction.

In another known electric drive motor (DE-OS 31 49 106) is formed by a permanent magnet stator of a ring, a magnetic yoke forming sheet metal strip surrounded axially adjacent on both sides of bearing carrier and is connected to this. This bearing support formed bügelförmit and take each one shaft bearing for the rotor shaft. One of these shaft bearing is designed as a rolling bearing, which is held directly in a pot-shaped recess of the bearing bracket and projects over the recess by a predetermined distance outwardly. This makes it possible, this bearing element necessarily absolutely concentrically lying to the armature shaft, namely to use in the specific case the outer ring of the rolling bearing, for catching and centering a further arranged at this engine assembly beispeilsweise a transmission. About the possibility of electrical interconnection Nothing is stated; greater effort is here, however, not necessary, since the stator consists of a permanent magnet.

It is also known (US Patent 4,613,781) to arrange an end cap assembly group with an electric motor on one side, comprising a plastic part, inside which a plurality of strip-shaped metallic wires are embedded, which establish the electrical connections between the motor components and the brush holders. To this end, each electrical line to make a brush holder contact, wound around a base portion of the brush holder, to which each brush holder has lateral flanges at its base.

Furthermore, the formation of the individual brush holder is such that a side wall is looped bent and extended so that they under the respective carbon brush reaches the manner of a hook in the brush holder and can hold this for assembly purposes in the distance to the collector ring of the anchor initially. Subsequently, namely, after assembly, the hook is pushed further to the outside, whereby the coal is released and the electrical contact between it and the collector of the electric motor is possible.

It is fenrer at an assembly for an electric motor is known (DE-GM G 85 20 258.4), a made of insulating and supporting circuitry plate with central cutout for receiving the collector of an electric motor to provide and on the plate oppositely angoerdnete integral frame parts for mounting of connectable with the circuit arrangement brush in such a way that lead of laterally arranged next to the frame parts spring retainers resiliently biased projections of the springs in the frame parts. The springs are wound helically on the spring brackets. At least a portion of the electrical circuitry is embedded in the plastic backing plate.

This embedding of the necessary for the operation of an electric motor wiring at least in its essential elements is also known from DE-OS 36 04 675, wherein an insulating member surrounds the conductor in its essential components, while other components superimposed for operation of the engine, for example, brush rockers, which are likewise integrated in the component. The component is plate-shaped and, a central bore for allowing the passage of the collector of the electric motor.

In a further electric motor of a known type (European Patent Application 0,235,443) are arranged on a ring-shaped support plate, a plurality of electrical components that contact with embedded in the support plate electrical wiring in that the carrier plate the electric lines for making contact frees partially. On the carrier plate likewise mounted brush holder, while enjoying the marginal extensions that are clipped manner of a latching on free conductor portions, so that can be a secure physical connection between the lines within the carrier plate and the brush holder housings produced. But the assembly effort to locate on the support plate, the plurality of components including a separate, wound Bürstenvorspannungsfedern and their support posts and store is considerable; Parts of electrical, embedded in the carrier plate lines are there from in the axial direction of this in order to achieve a contact is elsewhere, for example with the stator.

It is also known to form a cup-shaped bearing bracket for an electric motor for a small electric tool so as to receive the inserted it in the manner of a stator part of the casing, inside which, in turn, the rotor is mounted freely rotatable. The rotor shaft is seated on the side of the cup-shaped bearing bracket in a roller bearing, which is formed from the bearing bracket. Furthermore, the bearing bridge has means for switching on and off, field connectors and a suppression capacitor. On the bearing bridge is a contact grid is arranged, which is designed as a stamped grid for selectively connecting chokes, switches, diodes and resistors.

The punched grid is on the rotor-facing side of a switch arrangement. Here also is a circuit ring is provided in the rotation can be made different contact gifts, for example, to reverse rotation or speed reduction (European Patent Application 0224054).

In this context, it is also known (European Patent Application 0224053) to arrange the planar leadframe on one side of a carbon brush holder plate, the carbon brushes are located on the other side of the carbon brush holder plate. By vertically angled to the main plane of the punched grid connection tongues connecting contacts result for the field windings. The lead frame is formed as a continuous strip conductor made of metal and welded to the rotor-side surface of the plastic coal holder plate, glued or connected in some other way.

A problem with the known electric motors and components for this, that through certain individual features simplistic solutions are achieved, but in terms of the burden of individual parts, their assembly and installation of the electric motor be much too complex structures, especially considering that such electric motor should also have means to allow switching on and off, but above all also a switch in the rotational direction. Just the reverse rotation but is usually associated with a significant amount of circuitry, so that here, but also appear when storing the brushes and their good contact is made to the other circuit elements, at all throughout the basic structure and the construction of electric motors issues on which a substantially automated assembly and a cost-effective production of electric motors in the way.

The invention is therefore based on the object to provide a universal electric motor, with only a few individual parts makes do with very simple structure, where excellent reliability with high continuous power, meets every demand on the possibilities of electrical wiring including off switch and rotation reversal and nevertheless is designed such that it can be produced on automatic production lines, without thereby suffer stability and especially precise centering of the rotor with respect to the surrounding stator or whose pole shoes.

ADVANTAGES OF THE INVENTION

The invention solves this object with the characterizing features of claim 1 and the subsequent, independent claims and the method claim 24 and has the advantage that a self-contained universal motor is created that contains a precise and safe stabilization of the individual engine components, including each other precisely centering the rotor having circumferentially uniform air gap ensures the stator.

The universal motor of the invention can be mounted automatically Due to its distinct layer construction, with only a few items are needed and, in particular, despite the possibility of switching between forward and reverse rotation with a mean zero position of the wiring effort in the field of carbon brushes is low.

Especially advantageous is also that both end shields, so the drive-side bearing end shield and the brush-side end shield can be made of plastic in general cup shape, so that a particularly good insulation (double insulation) results, but still, in part due to separate stabilization plates and elements proper positioning of the parts is assured each other at fixed axial Bolt Down, further is of particular advantage that the universal motor in each machine or device housing to which it is assigned, no additional support parts needed to which it must be modeled, but finished having in itself full stability and further forms metallic attachment and points of attack, such as a metallic collar in the area of ​​the output-side bearing with, if desired, additional extruded holes, so that the cultivation of a corresponding transmission problems through the available clamping surfaces possible is. Here, the motor housing is guided on the inner laminated core of the stator on both sides in the layer construction of seized immaculate airflow and cooling by the motor interior, with especially intensive cooling air flows occur in the field of coal and the contacts.

A further advantage is the axial, yet excellent contacting of the respective contact points. in the changeover for the forward and reverse rotation, said spring contacts for tolerance compensation simply constructed are provided with a particularly good connection properties.

Another important advantage is that the contact paths for supplying the power to the stator and to ensure the switchover of clockwise and counterclockwise in the brush-side end plate (end shield) embedded or placed thereon, wherein an actual, the carbon brushes wearing switching ring which contacts the bearing plate as mentioned only contacted axially and itself has only the brushes connected, axial spring pressure contacts that are aligned with the rotation of the control ring on each other contacts in the bearing plate for pole reversal and Alike hzeitig to brush adjustment to improve the commutation.

Preferably both bearing shields have to achieve an exact centricity separate centering and ball bearing mounts on, is being used a metallic stabilizing plate in the A-side endshield and securely fixed to the base region, which receives the local ball bearings for the rotor shaft in a bulge and after by the outside outstanding covenant offers more mounting options.

The in this way a self-contained complete functional unit forming universal motor in layer construction can be automated for consistent mass production, with a particularly effective cooling air flow is ensured by the motor through the integrated installation of a fan.

A particular advantage is still to be seen in that axially adjacent to the fan one air guide is located inside the A-end shield, which is used in the manner of a bayonet fitting and simultaneously the tension rod for axial screw and end fixation of both bearing plates, the stator and the rotor bearing forms.

By the rotatability of the carbon brush holder supporting control ring also results in an average on-off function for the engine regardless of other external switches, for all type the same wiring in the range switching ring and zugewandem end shield can be used always.

In the automatic assembly of the assembly of the engine of a plane, ie from one side starting at the layered structure can be carried out, this can also be outside of the device in which it is to be installed, checked with care by the given possibility of complete external mounting of the engine ,

The rotation of the control ring to switch between forward and reverse rotation arises at the same time an appropriate contact cleaning, said contacts are disposed within a sealed space.

The measures specified in the dependent claims and dependent claims, advantageous developments and improvements of the electric universal motor are possible. Thus, carried by B-bearing plate contact bridges can be either embedded in the B-end shield as it were on edge in the form of webs, or they may be a flat sheet material is placed on this and secured by a corresponding latching, either by in of the flat sheet fins angled legs the material of the bearing plate to penetrate, or go out of this short holding warts of resilient sheet metal parts comprising on both sides, so that the sheet metal parts can be dig into the end position somewhat in the material of this holding pin or -warzen and not withdrawn when pressed.

drawing

Embodiments of the invention are shown in the drawing and are explained in the following description. Show it:<ul><li>FIG. 1 shows a possible embodiment of the universal electric motor of the invention in use even final assembly shape in longitudinal section and</li><li>Figure 2 shows the universal motor of Figure 1 in a view from the right with top view of the identifiable by an additional patch circlip switching ring with carbon brush storage..;</li><li>FIG. 3 shows one of the representation of FIG. 1 similar longitudinal section through the embodiment of the electrical universal motor, but in a view rotated by 90 ° relative to the Fig. 1 view, the</li><li>. Fig. 4 in longitudinal section right in the illustrations of Figure 1 and 3, so B-end shield shows;</li><li>Fig. 5 is a section along the line VV of Fig. 1, but showing only the A end shield, while the</li><li>Fig. 6 shows a cross section through the A-bearing plate with inserted and transferred by rotation in its secured end position Air deflection and Zugankerrings; </li><li>Fig. 7 and Fig. 8 show two respective end positions of the switching ring indicative plan views of these showing the carbon brackets, throttle cup and Kohlevorspannungsfedern while</li><li>Fig. 9 the switching ring of the B-end shield facing back shows and</li><li>. FIG. 10 is a detailed section along the line XX of Figure 9 indicates;</li><li>Fig. 11 4 shows a plan view corresponding to the B-end shield Fig. From the right, with this in embedded, the switching ring is not shown facing contact curves, while the</li><li>. Fig. 12 is a section along the line XII-XII of Figure 11;</li><li>Fig. Figure 13 illustrates a view of the B-end shield of FIG. 4 from the left represents from which view the two to be joined with the stator winding network connection contacts are visible, while the</li><li>Figs. 14 and 15 schematically the electrical wiring diagram of the universal motor according to the invention show, with the switching ring each in one or the other end stop and intermediate between the carbon brushes and the Statoranschlußpunkten suppression inductors; finally shows the</li><li>Fig. 16 two further possibilities of arranging and embedding the switching contact paths in the area of ​​the B-end shield.</li></ul>

Description of Embodiments

In Fig. 1, the electric universal motor with 10, which, in the drawing of Fig. 1 left, so drive-side A-side bell 11 and the right, brush-side end shield 12. The first given in the following overview of the overall structure is based on the description of the individual parts of the engine at the sukkzessiven sequence of assembly of these parts, as they are assembled in the fully or partially automated production and secured together, the universal motor, in the plane is built up starting from the left added successively.

The left-hand A-bearing plate has as principle and the B-end shield, a generally cup-shaped configuration and includes a base plate 11a which integrally merges preferably in the raised edge 11b. Preferably, the A-end shield and also the B-end shield of a suitable, tough plastic material, the edge 11b formed by a Abschulterung 11d a spigot for receiving the stator 13 side, possibly with the interposition of a seal 14th

Furthermore, the cup shape of the A-end shield has in the base plate via a circular recess 11c, which serves to receive a below will be explained Stabilisation and bearing plate 14th To secure the stabilizing plate 14 at the inner pot bottom of the A-end shield, the pot bottom preferably uniformly distributed over the circumference inwardly projecting material pin 15; Further holes 16 are also provided in the pot bottom of the A-end shield, which serve to receive and the passage of solid threaded openings 17 in the stabilizer plate 14th

The stabilizing plate 14 itself takes in a central protuberance on the outer ring 14a 18a a first ball bearing or roller bearing 18 for the rotor shaft 19th At this end occurs, the rotor shaft 19 and on the outline of the motor out, so that here, continue to be described, the torque produced by the engine can not be taken appropriately.

The stabilizing plate is thus introduced first during assembly into the cup shape of the A-end shield and receives its initial fixation by the penetration of the projections 15 in corresponding through-holes 14b of the stabilizing plate, with a subsequent assembly step, by appropriate heating, such as by laser -Beaufschlagung causes a widening in the overhanging head portion of the pin 15, so that the stabilizing plate is anchored to the bottom of the a-endshield. Here also the outer ring form of kicks in the ball bearing 18 receiving bulge on the rear surface of the pot bottom A-endshield forth, so that at this point clamping means or the like. can attack for mounting the engine or for mounting to be applied to the output shaft gear, etc..

Subsequently, the preassembled entirety of the rotor shaft 19 22 are inserted into the A-bearing plate with the rotor 20, the end of an annular stop of the rotor shaft 19 slid ball bearing 18 including the collector 21 and between the ball bearing 18 and the rotor securely stored on the rotor shaft 19 fan. It has, in more detail herein, the representation of FIG. 3, the cup shape of the A-end shield on over a portion circumferentially extending recesses or openings 23 in the amount of the fan 22, so that during operation of the electric motor of the fan 22 at this point of his can discharge through the motor interior from the right cooling air sucked by the outwards.

The other configuration and the following Assembly shall be then so forth, that in the cup shape of the A-end shield 11 another ring-shaped component is inserted, which in the following with reference to he developed auxiliary features for ventilation and cooling in conjunction with the fan 22 is referred to as the air guide 24, which still fulfills another important design task is equal to be discussed later.

The air guide 24 is cylindrically annular in shape with an inwardly projecting, adjacent to the fan wheel 22 annular edge 24a, so that the suction effect of the fan 22 is significantly improved in this area, which sucks air through its rotary motion from the center to the rotor shaft 19 around, where it leads to a partial vacuum, which ensures the same from the engine inside of the right for a corresponding flow movement of cooling air and this air then radially ejects through the ventilation holes 23 of the pot-shaped housing.

The outer annular surface of the air guide ring 24 fits flush into the inner opening of the A-side bell-pot shape, wherein the further anchor between these two components a catch is provided which can be referred to in the illustrated embodiment as a bayonet fuse. Specifically, this has, as FIG. 5 shows in more detail, the pot rim 11b of the A-end shield 11, for example diametrically opposite, via axial grooves 25, which merge into a predetermined level adjacent to the fan 22 side in wall openings 25a of the shield edge 11b. According aligned thereto, the cylindrical ring shape of the air guide ring 24 axial extensions of a same sleeve-like thickening 24b which pass outwards in projections 24c (Fig. 1) corresponding to the openings 25a of the A-side bell edge. It is located in the axial extension 24b simultaneously axial holes 24c, which serve to receive a clamping together of engine components serving screws 26 - then will be discussed below.

The air guide 24 is thus initially so axially fed into the cup shape of the A-end shield that its outwardly, a latching with the bearing plate serving projections 24c axially along the grooves 25 slide downward, whereby it is possible also, the air guide 24 in the cup shape of the A-end shield 11 insert. As soon as the air guide has reached the end position shown in FIGS. 1 and 3 (on the information and formed by the ends of the longitudinal grooves 25), the air guide ring is turned so far that the projections 24c 25a invade the Ausnehmunge so that the end position, as shown in FIG. 1 and in more detail in the illustration of FIG. 6 shows, in which the projections 24c are sunken into the window-like cutouts 25a and as safely fix the air guide in this position. The required rotation of the air guide ring is shown in Fig. 6 by the arrow A. It arises as a bayonet securing the air guide ring in a container housing the A-end shield and at the same time a fixed axial fixation of this air guide ring, which is used in its second position as a tie rod for clamping the two A- and B-bearing plates 11 and 12 through the turnbuckles 26th

In fact, after this assembly step, the Luftleitringpositionierung the left in the plane B-bearing plate is likewise pushed to the stop of Einpasses formed therefrom by a Abschulterung 12a on the stator, whereby a particularly advantageous embodiment of the present invention can still be seen in the fact that by the Einpaßbildung the two bowl-shaped bearing plates 11 and 12 take up the shield edges the stator on both sides and comprise their own edges over a predetermined distance B and B '(Fig. 3) and fix it, which contributes particularly advantageous for considerable stability of the universal motor according to the invention.

The B-side bell 12 is shown in Fig. 4 again separately and comprises first in one-piece construction, the cylindrical, cup-like basic shape 12a with the spigot edge formation, wherein the outer edge of the passage openings 12b for the clamping screws 26 to form a Abschulterung for investment of clamping screw heads are shown. In this area also are oval air openings 12c adjacent to the end windings 26 of the stator; similar openings in the amount of the winding heads are also in the edge 11b of the A-end shield and are designated therein by 27th This ensures that even at motor standstill effective cooling is carried out at then also stationary fan.

The cylindrical edge portion 12a of the B-end shield goes into a central axial extension 12d which forms a shoulder for receiving the right-side bearing 28 of the rotor shaft 19. The ball bearing 28, as shown in FIG. 1 in which is formed by the neck 12d Recording 29 possibly 30 sitting the interposition of a metal, then multiply stepped insert.

For the passage of sitting on a switching ring carbon brushes, the approach to 12d according generous passage openings 31, which also allow rotational movement of the brushes on the collector to the right-left switchover.

After pushing the B-end shield 12 to the previously described subassembly group of A-end shield, stabilizer plate, rotor with fan and air guide is all braced together by the previously mentioned clamping screws 26 passing through the through-holes 12b, through through-holes in the disk pack of the stator to in the receiving bore are out 24c of the air guide ring 24, which simultaneously forms thereby the tie rod for bracing.

The screwing of the provided with a corresponding self-tapping threaded ball turnbuckles 26 into the thread holes 24c of the air guide ring simultaneously causes, as best seen. Fig. 1 can be seen that the material projections strengthened 24c and are strongly pressed into the recesses or openings 25a in the A-end shield edge 11b so that is guaranteed simultaneously with the clamping together of secure positive seating of the tie rod and the same air guide ring. Optionally may be 25a still taken as the shape transition between the projections 24c and the recesses that this increasingly one another wedged by the increasing tension form-fitting, such as a kind of dovetail assurance; Here the mating surfaces still diagonal can have. Thus, although up to this assembly step no positioning of coal or electric coals or electrical contacts has been made, the universal motor is up to this area fully assembled, including the two bearings 18 and 28 for the rotor shaft 19 and the proper centering of the rotor between the two another and to the stator bolted and clamped A- and B-bearing shields.

Here, however, is a measure for the interconnection in the contact region of crucial importance is that it is the B-end shield itself, which carries a counter element to already mentioned and shown in Figs. 7, 8 and 9 illustrated switching ring contact paths and superimposed, the surface on the end face 32 of the B-end shield (Fig. 4) lie in the transition to the neck 12d and at least in this level flat contact areas for, and this is also an essential part feature of the present invention, form axial contact.

The end shield is therefore in addition to his other duties nor main contact carrier for the electrical connection of the stator and to enable Kohlebürstenkontaktierung, said contact trajectories best emerge from the representation of FIG. 11 in conjunction with FIG. 13.

Fig. Figure 11 shows the outwardly facing annular surface 32 of the B-end shield 12, so that the through hole 12b can be seen here for the clamping screw fastening. The power feed plug contacts are denoted by 33a, 33b; they are, as well as Fig. 3 shows, by the material of the end face 32 is passed and then extend within this material as secant longitudinal webs 33a ', 33b' and contact, as FIG. 13 shows, as an axial plug contacts 33c, 33a, 33b on the stator facing side of the B-end shield, which is 13 in Fig. recognizable reproduced, then where the electrical connection through respective axial connector contacts with Statoranschlußklemmen.

To decrease the leading away from the stator terminals then, the B-end shield to complete the corresponding axial plug-in contact arrangement in a square more plug contacts 34a, 34b, which in turn in the in Fig. 11 recognizable two contact tracks 34b ', 34a' pass. As such, the contact track history is especially the partially repeatedly bent contact web webs 34a ', 34b' arbitrarily; . In which in Figures 11 and 13 illustrated embodiments are those contact paths, the flat bars are, as it were embedded on edge in the material of the B-end shield face 32 - here, however, other embodiments are possible, as in the following then specifically with reference to the representation of FIG. will be explained in the 16th

However, it recognizes the previously described course of the contact rails or tracks with further reference measure to the representation in FIGS. 14 and 15 that the current waveform is generally as shown in Fig. 14, so the overhead power supply to the contact path 33b 'and from this via an axial plug-in contact on the field winding II, II of the field winding to the first switching contact rail 34a'; of this Umschaltkontaktschiene through one of its axial terminal contact points - then will be discussed - the carbon brush I 'and the rotor on the carbon brush II', of this to Umschaltkontaktschiene 34b 'and the educated of this axial plug contact 24b to the field winding II back on the second power contact beam 33a 'to shown in FIG. 14 lower network connection.

One then detects also the same as compared to FIG. 15, which shows the same view of FIG. 14 only with twisted carbon brushes switching ring, in that the carbon brushes connected via the collector to the rotor, the rotor ports in the respective switching Verdrehendlagen with reference to the umpolen maintained field winding polarization, with a corresponding change of direction and at the same time repositioning the carbon brushes contact regions on the collector, so that can be achieved equally good commutation in both cases, and therefore for both directions of rotation, a similar efficiency can be achieved.

Therefore, as just explained above, form of the switch-over 34a 'and 34b' that are embedded into the end face material of the B-end shield or laid on this, in each case two contact points or contact areas, which in Fig. 11 each of X and X ', or Y and Y ', respectively.

Through this entry or attachment of the contact rails or contact bridges in bzw.am end shield arises simultaneously an effective relief of the structure of the switching ring, which is shown more clearly in Figs. 7, 8 and 9, Figs. 7 and 8 show the same view, respectively in the two end stops of the switching ring to switch between forward and reverse running, while Fig. 9 shows the control ring from the other side then. This switching ring, which is denoted by 35, then only transmits nor the quiver 36 for supporting the carbon brushes I ', II' with the corresponding biasing springs 37 for the carbon brushes, and is preferably constructed of a suitable stable insulating material (plastic, as in the moreover, Zugankerring 24, the two end shields, a securing ring for the switching ring, and optionally the fan 22). . Since according to the representation of Figure 1, the contact points X, X '; Y, Y 'for the electrical terminal connecting to the coals than in the plane of the end face 32 opposite axial flat contacts are formed, it is necessary that also the switching ring on the corresponding facing side forms corresponding axial flat contacts that then over the entire surface axially in said plane in so far rest on the contact surfaces formed by the Umschaltkontaktstegen. For this purpose, the procedure is such that, even for achieving the required Kontaktanpreß spring force to make contact on the side opposite to the rotor side of the switching ring 35 axial hollow projections are arranged in the direction of the end face 32 and the overlapping on these contacts, X, X ', Y , Y 'of the B-end shield 12 are open - such a hollow projection is shown between the two 7 and 8 above in section and indicated at 38... Of this sectional view corresponding section is indicated in Fig. 8 with yy.

Within the hollow projection, a U-shaped manner bent contact bracket 39 is 40 as stored under the bias of a spring such that its contact surface 39a is biased by the spring 38 in the direction of the contact areas X, X ', Y, Y' of the Umschaltkontaktstege 34a ', 34b' , where, as shown in FIG. 11 can be seen, this axial contact surfaces of Umschaltkontaktstege are obtained in this embodiment by turns the edge embedded in the material of the B-end shield contact rail curves.

The U-shaped contact bracket 39 penetrates at a location of its contact surface 39a opposite to a contact tongue 41 the hollow projection 38, and the contact terminal is in this reed then 42 put, which is connected as shown in FIG. 7 with the respective carbon brush. Such wide-scale axial contact not only ensures correct contact, but also a constant cleaning effect on the contact surfaces, as they grind to reach the respective Kontaktendposition successive pressurized.

The basic concept of the invention in construction and especially in the area of ​​switching and contact-making means of the so far only low-load switching ring 35 makes a further advantageous embodiment of the present invention possible is that without major problems for receiving series between field winding and carbon brushes chokes 43 choke cup 44 on the ratchet ring with integrated can be recorded. The inclusion of chokes in the motor current circuit can then be achieved by simply changing; For example, in the illustration of FIG. 7, the respective carbon brush terminal directly connected to the contact tongue 41 of resilient U-bolt contact, so it is also possible that resulting from the respective carbon brush connection contact terminal 42 '(Fig. 8) with a separate, adjacent to Contact tongue 41 arranged contact tongue 43 to connect the other end, as shown in Fig. 8 by dashed lines at 45 is shown, in the switching ring 35 under and along the choke cup to whose other terminal is performed, so that then switching the throttle 45 whose other terminal by means of the usual clamping connection 46 can attach to the contact tongue 41st

The respective end positions and an additional middle-zero position for the contact switching between forward and reverse rotation can finally by one or two, then preferably diametrically opposite material tongues 47 of the switching ring 35 are designed with detent; this material tongues are cut out to extend peripherally along partial circles at the inner periphery and feature a trimmed on the end face 32 of the B-end shield projection 48, as shown in Fig. 10. This nose-like projection 48 to snap into recesses 50, 50 ', 50˝ which extend along respective pitch circles in the end face 32 of the B-end shield, and thus position the two end positions for switching right-left and the center position in the detent 50, in which the motor is then switched off simultaneously. Thus, this results in the possibility of one-off of the engine simultaneously with the switching between forward and reverse rotation.

The switching ring 35 is together with the just described assembly slid over the neck 12d of the B-end shield as far until it rests with its facing, resilient contacts 39a on the annular end face 32 of the B-end shield.

In order to fix the switch ring is finally a retaining ring 51 (FIG. 12) is provided which holds preferably detects the outer ring edge of the ratchet ring 35 by an inwardly projecting annular flange 51a and implementing the corresponding rotational movement, wherein the securing ring 51 itself by means of the best uniformly engages distributed around the circumference axial projections 51b, which are provided at their ends with locking tabs 52 in corresponding recesses 53 on the outer wall of the B-end shield 12th

The construction of the universal motor complete hereby, so that allowed for out of a plane, automatic production only seven subcomponents are required in total, namely, the left in the drawing of Fig. 1 A-end shield that its bottom associated with stabilizing plate, which is then used pre-assembly of the rotor shaft, rotor, fan and the two camps, the same time the tie rod forming air guide, the right-side end shield, the patch on the free outward-facing and the corresponding contact rails and webs supporting annular surface switching ring and the latter in its Teilverschwenkbarkeit on the B-bearing shield retaining snap ring.

In respective embodiments of the present invention, it is finally possible, this entire area instead of it were vertically embedded into the face material of the B-end shield and by bending the axial flat contacts forming contact rails and springs also in accordance with already pre-bent and punched ring shape, as shown at 34a to hang on the face with the two end contacts Y₁ and Y'₁ and, so to speak, by bent insert land areas, as they are seen at 54 in the face material of the B-end shield and secure way.

An alternative embodiment, finally, there is still the fact that in also full surface contact, as in 34b 'recognizable, the fixing of such extending in a semicircle flat rail can also be done without additional bends by leaving free at certain places in the flat bar material ports 55, both sides resilient to the webs 56 adjoin. In this known in itself seen fixing method then the opening 55 is penetrated by a slightly larger diameter,, protruding from the annular end face of the B-end shield pin, in its adjoining edge areas then dig the sharp leading edges of the springs 56, so that a withdrawing a thus fixed contact strip is then excluded. It is understood that the fixing takes place multiply at appropriate locations. These two types of mounting are next to the explained in the first embodiment embedding (optionally by extrusion coating) of the contact webs possible because these contact webs are so to speak, still additionally held by the axial contact is made through the attached shifting ring. The type of contact made here thus comprises a spring contact with U-bolts including spring when expressly axial contacting and contacting in a plane through the respectively developed by the spring compression pressure.

The carbon brushes receiving coal guides and the throttle cups can be directly molded onto the switching ring, the interposition of the reactors by repositioning is no problem and the leading to the throttle contact as contact web below the throttle cup is conducted, so that is working here with low space requirement.

All in the description, the subsequent claims and the drawing can be essential to the invention both individually and in any combination.