Abstract:
An electric motor has a rotor ( 52 ) and a stator ( 60 ) equipped with salient poles on each of which is provided a winding ( 88  to  99 ), which windings together form a winding arrangement ( 85 ′), electrical connecting leads ( 88 ′ to  99 ′) being provided between at least some of the windings. The stator ( 60 ) further has electrical connecting elements ( 108  to  119 ) that are arranged on at least one insulating carrier ( 102 ) and are equipped with contact elements ( 108 ″ to  119 ″) and with mounting elements ( 108 ″″ to  119 ″″), which latter serve for electrical and mechanical connection to the connecting leads ( 88 ′ to  99 ′). The use of a printed circuit board ( 140 ) formed with press-fit seats, to receive the contact elements, facilitates rapid, secure and automated connection of stator windings to other circuit parts, which is particularly useful in making low-voltage, high-current motors such as those used in mining.

Description:
CROSS-REFERENCE 
     This application is a sec. 371 of PCT/EP07/08792, filed 10 Oct. 2007 and published 17 Apr. 2008 as WO 2008-43534-A1, which claims priority from DE 20 2006 016 357.3, filed 14 Oct. 2006, the entire content of which is incorporated by reference. 
     FIELD OF THE INVENTION 
     The invention relates to an electric motor having a stator that carries a winding arrangement that is configured to generate a rotating field. 
     BACKGROUND 
     A three-phase motor (rotary current motor) can be operated in a Y circuit configuration (Y configuration) and in a delta configuration. If, in the context of a Y circuit, the individual windings of each phase are connected in series, this is referred to as a “Y series” circuit; and if two individual windings per phase are connected in parallel, this is referred to as a “Y double-parallel” circuit, If four individual windings are connected in parallel, the term used is a “Y quadruple-parallel” circuit. Analogously, the terms “delta series” circuit and “delta double-parallel” circuit (see  FIG. 3 ) are used, or a “delta quadruple-parallel” circuit is referred to. 
     The winding ends of the individual coils must be connected to one another in different ways, in order to manufacture the various circuit configurations of this kind. In the case of the motor according to U.S. Pat. No. 6,177,741 B1, Lütkenhaus et al, for example, the stator of which is equipped with a Y circuit, the ends of the lacquered copper wires are connected, by means of soldered or crimped connections, to the ends of flat conductive tracks that are mounted on an insulating plate. One of these conductive tracks serves as a neutral-point connector, and three other conductive tracks serve as the terminals for the U, V, and W phases. This requires a great deal of manual work. 
     SUMMARY OF THE INVENTION 
     It is therefore an object of the invention to make available a novel electric motor whose assembly requires much less manual work. 
     According to the invention, this object is achieved by a motor having a plurality of poles, each equipped with a stator winding. Each stator winding engages a mounting element on an electrical connecting element which makes contact with a respective receiving opening formed in a connecting arrangement, e.g. a printed circuit board. Preferably, the motor circuit is assembled in an automated manner by pressing all the contact elements into the receiving openings more or less simultaneously. 
     In accordance therewith, the winding ends of the individual windings can easily be connected to the mounting elements of the associated connecting elements, for example by resistance welding, with the result that low contact resistance values are obtained. The connecting elements can in turn be electrically connected in the desired fashion by means of a functionally appropriate connecting arrangement in order to obtain, for example, a Y double-parallel circuit or a delta quadruple-parallel circuit. A connecting arrangement of this kind can be implemented as a connecting board having electrical conductors, each of which is connected to specific associated connecting elements by means of contact elements such as, for example, press-in pins or contact pins, so that low contact resistance values are obtained here as well. These press-in pins can quickly and easily be pressed into corresponding press-in seats in the connecting board. 
     The invention thus enables rapid, uncomplicated, and highly automated production of high-quality stators that can be used at high ambient temperatures and/or high current intensities and/or in a context of severe vibration stress. One preferred application is motors for low operating voltages such as those that must be used for safety reasons in mining, where such motors are subject to particularly severe vibration stress and at the same time a high level of operating reliability is demanded. 
    
    
     
       BRIEF FIGURE DESCRIPTION 
       Further details and advantageous refinements of the invention are evident from the exemplifying embodiments, in no way to be understood as a limitation of the invention, that are described below and depicted in the drawings. 
         FIG. 1  is a usual depiction of a stator having a winding arrangement, and having connecting elements according to the present invention; 
         FIG. 2  is a depiction analogous to  FIG. 1 , with a connecting arrangement according to the present invention; 
         FIG. 3  depicts a delta double-parallel circuit; 
         FIG. 4  depicts a stator having six slots and six teeth, as well as the winding arrangement according to  FIGS. 1 to 3  arranged thereon; 
         FIG. 5  is an exploded depiction of a stator having twelve coils and corresponding connecting elements, according to a preferred implementation of the invention; 
         FIG. 6  is a perspective depiction of a portion of the stator of  FIG. 5  having two connecting elements, after winding of the winding arrangement; 
         FIG. 7  is a perspective depiction, at a scale of approximately 1:1, of a portion of the stator of  FIG. 5  having a connecting element, after winding of the winding arrangement; 
         FIG. 8  is a perspective depiction of the stator of  FIG. 5  after stacking; 
         FIG. 9  is a schematic side view of the completed stacked stator of  FIG. 8 ; 
         FIG. 10  is a perspective depiction of the connecting elements of  FIG. 5 ; 
         FIG. 11  is a depiction showing the installation of upper board  140  on the stator, the board being pressed on in the direction of an arrow  200 ; 
         FIG. 12  is a sectioned view through the depiction of  FIG. 6  along section line A-A; 
         FIG. 13  is the sectioned view of  FIG. 12  with an example of a pair of welding tongs, to illustrate a resistance-welding operation; 
         FIG. 14  is a perspective depiction of a further connecting element according to the present invention such as the one used in  FIG. 5  and  FIGS. 8 to 10 ; 
         FIG. 15  is a plan view of a circuit board  140  used in the context of the invention; and 
         FIG. 16  is a schematic, exemplifying depiction of the conductor paths in circuit board  140  of  FIG. 15 . 
     
    
    
     DETAILED DESCRIPTION 
     In the description that follows, the terms “left,” “right,” “upper,” and “lower” refer to the respective figure of the drawings, and can vary from one figure to the next as a function of a particular orientation (portrait or landscape) that is selected. Identical or identically functioning parts are labeled with the same reference characters in the various figures, and usually are described only once. 
       FIGS. 1 to 4  show a first exemplifying embodiment of the invention, namely a motor having six salient stator poles  11 ′ to  16 ′ onto which six coils  11  to  16  are wound continuously and codirectionally. The slot between poles  11 ′ and  12 ′ is labeled  21 , the slot between poles  12 ′ and  13 ′ is labeled  22 , and so on for slots  23  to  26 . 
     This continuous winding  30  is intended for a delta double-parallel circuit  28  as depicted in the usual way in  FIG. 3 . 
     According to  FIG. 1 , the continuous winding  30  starts at its beginning  31  at hook  32  of an electrical connecting element W′, then goes to coil  11 , one of whose halves is shown on the right in  FIG. 1  and the other half on the left, proceeds to a hook  34  of a connecting element U, then goes on to a coil  12  and from that to a hook V 1  of a connecting element V and from there on to coil  13 . 
     From coil  13 , the continuous winding  30  goes to a hook W 1  of a connecting element W, from there to coil  14 , and from that on to a hook U′ 1  of a connecting element U′. 
     From there the continuous winding  30  proceeds to coil  15 , and from that on to a hook V′ 1  of a connecting element V′. 
     From there the continuous winding  30  proceeds to coil  16 , and from there its end  35  goes to a hook  36  of connecting element W′, with which the circuit closes, since hooks  32  and  36  are electrically connected to one another via connecting element W′. 
     At each connecting element U, U′, V, V′, W, and W′, one contact element  81 ,  82 ,  83 ,  84 ,  85 , and  86  is provided for illustration. This element serves for the electrical connection of different connecting elements, as described below with reference to  FIG. 15 . Contact elements  81 ,  82 ,  83 ,  84 ,  85 , and  86  are depicted in  FIG. 1 , by way of example, as resilient press-in pins, each contact element comprising two such press-in pins. The number of press-in pins depends on the current that is to be transmitted through them; it is generally the case that a single press-in pin can be sufficient for low currents, whereas at least two press-in pins are necessary for higher currents. It is noted, however, that the press-in pins are depicted merely as an example for the implementation of contact elements  81 ,  82 ,  83 ,  84 ,  85 , and  86 . Other implementations such as, for example, contact pins can also be carried out, and may be specified, depending upon the industrial application for which a relevant motor is used. 
     The arrangement depicted in  FIG. 1  is merely an intermediate product for the manufacture of the delta double-parallel circuit  28  according to  FIG. 3 .  FIG. 2  shows how manufacture of the circuit is completed by way of a connecting arrangement  40 . Connecting arrangement  40  has a connection  42  for electrical connection of connecting elements U and U′ of  FIG. 1  via contact elements  81  and  84 , as well as a connection  44  for electrical connection of connecting elements V and V′ of  FIG. 1  via contact elements  82  and  85 , and a connection  46  for the connection of connecting elements W and W′ of  FIG. 1  via contact elements  83  and  86 . A preferred configuration of connections  42 ,  44 ,  46  is described below. 
     As shown in  FIG. 1 , connecting elements U, U′, V, V′, W, and W′ are mounted on an insulating ring  50  that is highlighted by a dot pattern in  FIG. 4 .  FIG. 4  also shows a rotor  52  and its shaft  54 , as well as rotation axis  56  around which rotor  52  rotates. 
     The latter is depicted as a two-pole permanent-magnet rotor corresponding to operation as a synchronous motor or three-phase generator, but it is of course also possible to use a rotor having a short-circuit winding, or an eddy-current rotor, in order to enable operation as an asynchronous machine. 
     Ring  50  is located at one end of the stator and concentrically with rotation axis  56 , so that connecting elements U, U′, V, V′, W, and W′ are at approximately the same distance from rotation axis  56 . 
     Examples of embodiments of the motor according to  FIGS. 1 to 4  are also described in our WO 2006/050765 A1, KIENZLER, ALTINDIS, WEISSER &amp; MAIER, (commonly assigned with the present application) whose US National Phase is Ser. No. 11/718,800, published 27 Dec. 2007 as US 2007/0296292-A. 
       FIG. 5  is an exploded perspective depiction of a stator  100  having a completely stacked stator lamination stack  60  having slots  61  to  72 , the lamination division principle of which has already been described with reference to  FIG. 4 . Slots  61  to  72  of lamination stack  60  are lined, in the usual fashion, with an insulator. 
     In contrast to  FIG. 4 , stator lamination stack  60  of  FIG. 5  comprises twelve coils  88  to  99  with which this lamination stack  60  is wound, preferably, using a single winding wire. These twelve coils are, by way of example, connected in a winding arrangement  85 ′ to form a delta quadruple-parallel circuit. For this purpose, during stacking at least some of coils  88  to  99  are connected to one another via corresponding connecting leads. In  FIG. 5 , coils  88  to  99  are connected to one another, illustratively, via associated connecting leads  88 ′ to  99 ′; coils  88  and  89  are connected to one another via lead  88 ′, coils  89  and  90  via lead  89 ′, etc. 
     As is evident from  FIG. 5 , connecting lead  93 ′ is split approximately in the middle and comprises a first end  142 ′ and a second end  144 ′. The latter are mounted, separately from one another, on the two hooks forming mounting element  113   IV , as described below with reference to  FIG. 10 . 
     Located at the lower (in  FIG. 5 ) end of lamination stack  60  is an annular insulating molded part  77  that forms parts  78  of the coil formers for the individual coils. Located at an upper (in  FIG. 5 ) end of lamination stack  60  is an annularly implemented carrier  102  on which, once again, parts  76  of the coil formers for the individual coils or individual windings are provided. Carrier  102  is also shown as having axial openings  108 ′ to  119 ′ for the reception of electrical connecting elements  108  to  119 . These are illustrated at greatly enlarged scale in  FIG. 10 . 
     Arranged in opening  113 ′ is connecting element  113 , which is equipped with a contact element  113 ″ and is implemented analogously with connecting element W′ of  FIG. 1 . Arranged in openings  109 ′ to  112 ′ and  114 ′ to  117 ′ are connecting elements  109 ′ to  112 ′ and  114 ′ to  117 ′, respectively, which are equipped with contact elements  109 ″ to  112 ″ and  114 ″ to  117 ″ and are implemented analogously with connecting elements U, U′, V, V′, and W of  FIG. 1 . A greatly enlarged perspective view of connecting element  114  is provided, by way of example in  FIG. 11 . Connecting elements  108 ,  118 , and  119 , equipped with contact elements  108 ″,  118 ″, and  119 ″ respectively, are arranged in openings  108 ′,  118 ′, and  119 ′. A greatly enlarged perspective view of connecting element  108  is provided, by way of example, in  FIG. 14 . 
     Contact elements  108 ″ to  119 ″ are depicted in  FIG. 5 , by way of example, as resilient press-in pins. Upon assembly, these are introduced into associated receiving elements  188  to  199  of a connecting arrangement  140  that is preferably implemented as a circuit board, and are then connected there to corresponding electrical conductors as described with reference to  FIG. 15 . 
     Receiving elements  188  to  199  are preferably implemented as press-in seats into which the corresponding press-in pins are pressed. This creates a stable, pull-resistant connection between contact elements  108 ″ to  119 ″ and connecting arrangement  140 , which connection serves, for example, for the electrical connection of different coils in order to produce the delta quadruple-parallel circuit configuration of stator  100 . 
     As is evident from  FIG. 5 , connecting elements  108 ,  118 , and  119  comprise, on their lower (in  FIG. 5 ) sides, additional contact elements  108 ′″,  118 ′″, and  119 ′″, respectively. These serve for electrical connection of winding arrangement  85 ′ to a supply voltage source (e.g. a three-phase current system or an output stage) via a further connecting arrangement  170  implemented as a circuit board, on which arrangement other electronic components of the motor electronics can also be arranged. Analogously to contact elements  108 ″ to  119 ″, contact elements  108 ′″,  118 ′″, and  119 ′″ are implemented as press-in pins that are pressed into receiving elements  172 ,  174 , and  176 , implemented as press-in seats, in connecting arrangement  170 . A stable, pull-resistant connection of contact elements  108 ′″,  118 ′″, and  119 ′″ to connecting arrangement  170  is thereby created. 
     As  FIG. 5  shows, connecting elements  108  to  119  comprise hook-shaped mounting elements  108   IV  to  119   IV  into which connecting leads  88 ′ to  99 ′ are hooked. Connecting lead  88 ′ is hooked into hook  108   IV , lead  89 ′ into hook  109   IV , etc. Leads  88 ′ to  99 ′ are mechanically and electrically connected to the associated hooks  108   IV  to  119   IV  by resistance welding. This is described with reference to  FIGS. 11 to 13 . 
       FIG. 6  is a perspective depiction of a greatly enlarged portion of stator  100  of  FIG. 5 , having connecting elements  114  and  115 , after the winding of winding arrangement  85 ′, of which only individual windings  94 ,  95 , and  96  are at least partly visible in  FIG. 6 . 
       FIG. 6  illustrates the mounting of connecting elements  114  and  115  in carrier  102 , and the hooking of the connecting leads into the relevant hooks of the connecting elements, using the example of leads  94 ′ and  95 ′. The latter are hooked into hooks  114   IV  and  115   IV  of connecting elements  114  and  115 , respectively, and are welded to them by resistance welding as described below with reference to  FIGS. 12 and 13 . 
       FIG. 6  also illustrates a preferred implementation of the contact elements. As is evident from  FIG. 6 , contact elements  114 ″ and  115 ″ are each made up of two resilient press-in pins  182 ,  184  and  183 ,  187 , respectively, which are described in detail below with reference to  FIG. 11 . 
       FIG. 7  is a perspective depiction of a portion of the stator of  FIG. 6  having connecting element  115 , after winding and at a scale of approximately 1:1. 
       FIG. 8  is a perspective depiction of the completely assembled stator  100  of  FIG. 5 . 
       FIG. 8  illustrates the mounting of connecting arrangement  140  on connecting elements  108  to  119  by way of contact elements  108 ″ to  119 ″ arranged in the associated receiving elements  108 ′ to  119 ′.  FIG. 8  also shows the mounting of connecting arrangement  170  on connecting elements  108 ,  118 , and  119  via contact elements  108 ′″,  118 ′″, and  119 ′″ (not visible) arranged in the respective associated receiving elements  172 ,  174 , and  176  (not visible). 
     For the manufacture of stator  100 , firstly carrier  102 , stator lamination stack  60 , and the annular molded part  77  are arranged one above another, and connecting elements  108  to  119  are mounted in carrier  102 . Winding arrangement  85 ′ is then wound, in which context connecting leads  88 ′ to  99 ′ between the individual coils  88  to  99  are hooked into the associated hooks  108   IV  to  119   IV  (see  FIG. 6 ). Leads  88 ′ to  99 ′ are then welded by resistance welding to the relevant hooks  108   IV  to  119   IV , as described with reference to  FIGS. 12 and 13 . Connecting arrangements  140  and  170  are then mounted on contact elements  108 ′ to  119 ′ and  108 ′″,  118 ′″, and  119 ′″, respectively. 
       FIG. 9  is a schematic side view of the stator of  FIG. 8  and the mounting of connecting arrangements  140  and  170  on connecting elements  108 ,  118 , and  119 , and the mounting of the connecting leads on their mounting elements, e.g. lead  97 ′ on hook  117   IV . 
       FIG. 10  is a perspective view of connecting elements  108  to  119  of  FIG. 5 . A preferred implementation of connecting element  114  is shown greatly enlarged in  FIG. 11  and described there. A preferred implementation of connecting element  108  is shown greatly enlarged in  FIG. 14  and described there. 
       FIG. 10  illustrates the fact that only mounting element  113   IV  of connecting element  113  has two hooks  142  and  144 . As described with reference to  FIG. 5 , according to a preferred implementation of the invention, winding arrangement  85 ′ is wound with a single winding wire. End  142 ′ of this wire is mounted, for example, on hook  142  before winding. Coils  94  to  99  and  88  to  93  of  FIG. 5  are then wound, and the other end  144 ′ of the winding wire, coming from coil  93 , is mounted on hook  144 . The circuit is thus closed at hook  144 , since the latter is electrically connected via connecting element  113  to hook  142 . 
     As likewise illustrated in  FIG. 10 , only connecting elements  108 ,  118 , and  119  have lower contact elements  108 ′″,  118 ′″, and  119 ′″, respectively, for connection to a corresponding supply voltage source, since three terminals are sufficient for connecting a three-phase motor. 
       FIG. 11  shows the assembly of circuit board  140  by pressing onto the contact elements in the direction of an arrow  200 ; this is usually followed by a soldering operation. 
       FIG. 12  is a greatly enlarged sectioned depiction of hook  114   IV  with a connecting lead  94 ′ arranged therein, looking along section line A-A of  FIG. 6 . Lead  94 ′ has lacquer insulation  94 ″. 
       FIG. 13  shows a resistance welding procedure in which lead  94 ′ is welded to a hook  114   IV  using welding tongs  150  that are closed in the direction of two arrows  202 ,  204 . For this purpose, welding tongs  150  are guided from above over element  114  and then brought horizontally against hook  114   IV . The latter is bent together over lead  94 ′ with the aid of welding tongs  150 , and at the same time is heated by a current flowing through welding tongs  150 . This current heats wire  94 , and its insulation  94 ″ burns off. The result is that lead  94 ′ is welded to hook  114   IV , and a mechanically stable and electrically conductive connection is produced. 
       FIG. 14  is a greatly enlarged perspective view of connecting element  108 . This figure shows a preferred implementation of the contact elements as resilient press-in pins. These resilient pins, also called “press fits,” each have two lateral flexural elements  182 ′,  182 ″ and  184 ′,  184 ″. When press-in pins  182 ,  184  are pressed into an associated opening of board  140 , flexural elements  182 ′,  182 ″ and  184 ′,  184 ″ are compressed, i.e. flexural elements  182 ′ and  182 ″ are pressed against one another, as are flexural elements  182 ′ and  184 ″. 
     As a result of the resilient movement of the flexural elements in mutually opposite directions, press-in pins  182 ,  184  are mounted in stable fashion. Electrical contact with a conductor path, as described below with reference to  FIG. 15 , is generated and maintained, in that context, by the resilient property of press-in pins  182 ,  184 . 
       FIG. 15  once again shows circuit board  140  of  FIGS. 5 and 8 . It has twelve receiving elements  188  to  199  in the form of through-contacted hole pairs into which, as shown in  FIG. 8 , the various contact elements  108 ′,  108 ″ to  119 ′,  119 ″ are pressed, thereby creating the necessary electrical connections for the individual stator windings. A soldering operation is not required for this. 
     As in  FIG. 8 , connecting element  108  is connected onto receiving element  188 , connecting element  119  onto receiving element  199 , and connecting element  118  onto receiving element  198 . These connecting elements are indicated only symbolically. 
       FIG. 16  schematically shows the internal connections that are provided in circuit board  140  on different planes, and that preferably are completely embedded into circuit board  140 . 
     A first internal annular lead  120  is connected to terminal  108  and, as depicted, is connected to receiving elements  188 ,  191 ,  194 , and  197 . This annular lead  120  can constitute the U phase. 
     A second internal annular lead  122 , to which receiving elements  189 ,  192 ,  195 , and  198  are connected, is connected to terminal  118 . These elements can constitute the W phase. 
     A third internal annular lead  124 , to which receiving elements  190 ,  193 ,  196 , and  199  are connected, is connected to terminal  119 . These elements can constitute the V phase. 
     The invention has been described above with the aid of exemplifying embodiments in order to facilitate comprehension by the skilled artisan. The invention can of course be varied in many ways. For example, in  FIG. 16  it would be sufficient to arrange one of the three annular leads  120 ,  122 ,  124  in the interior of board  140 . In this case a second annular lead can be arranged on the upper side of board  140 , and in this case the third annular lead is arranged on the lower side of board  140 . Such modifications, and similar ones, occur to the skilled artisan based on practical requirements, e.g. the number of phases, the number of stator poles, and the manner in which those stator poles are interconnected. It is particularly advantageous that a stator of this kind can be manufactured in large automated fashion, since the winding, as depicted e.g. in  FIG. 1 , can be wound continuously, and the electrical connections to the individual hooks can likewise be made automatically using welding tongs, whereupon the hooks can be electrically connected by means of circuit board  140  in the requisite manner. Instead of attaching the winding wires by welding the winding wires held in the hooks, the use of insulation displacement contacts is also possible.