Abstract:
A method for manufacturing a coil of an electrical machine includes providing a laminated core having a first and a second slot, and inserting a first winding segment in the first slot to a first region having a first end portion and a second winding segment in the second slot to a second area having a second end portion. The method includes adhering the first end portion by inserting in a first recess a bending device and by positioning of a retaining element into a locking position in the first recess, and holding the second end portion by inserting in a second recess of the bender. The method includes bending the first and the second range in a bending direction to a first bending angle. The method also includes releasing the first end portion, and turning the second region in the bending direction to a second bending angle.

Description:
TECHNICAL FIELD 
       [0001]    The disclosure relates to a method and to a device for producing a winding of a winding carrier, which is of a stator or a rotor, of an electric machine. 
       BACKGROUND 
       [0002]    Electric machines include winding carriers that include a laminated core together with windings that are inserted into the laminated core and are realized as stators or rotors of the electric machines. In this case, the windings are realized from a number of winding pins (also referred to as winding rods) which are realized in a hairpin-shaped or a U-shaped manner and include in each case two legs as winding segments. 
         [0003]    To form windings, the two legs of the respective winding pins are interlocked and cranked by way of an expanding step via a winding pitch of the winding carrier such that the two legs, which are cranked with respect to one another, of each individual winding pin are able to be inserted into corresponding slots of the laminated core, which are provided for that purpose, corresponding to the winding pitch of the winding carrier. 
         [0004]    Exposed regions, which protrude from the laminated core, of the two legs of the respective winding pins are then, also corresponding to the winding pitch of the winding carrier, interlocked at in each case a predefined bending angle and are connected electrically to exposed regions, which are also interlocked at a predetermined bending angle, of the legs of the respective winding pins which are arranged spaced apart corresponding to the winding pitch. 
         [0005]    To produce electrical connections between the windings and an external power source or control device, exposed regions of legs of a few selected winding pins are interlocked at a bending angle that deviates from the previously named bending angle compared to the legs of the remaining winding pins. 
         [0006]    As is usual in the case of technical components, there is a general requirement in the case of electric machines to produce them, where possible, cost-efficiently in a simple production process. The requirement is very important in the automotive sector in particular. 
       SUMMARY 
       [0007]    Therefore, it is desirable to have a method and device configured to provide a simple and cost-efficient option for producing a winding carrier of an electric machine and consequently an electric machine. 
         [0008]    One aspect of the disclosure provides a method for producing a winding of a winding carrier, which is of a stator or a rotor, of an electric machine. 
         [0009]    The method includes providing a laminated core that includes at least one first slot for receiving at least one first winding segment of the winding and at least one second slot for receiving at least one second winding segment of the winding. The method also includes: inserting the at least one first winding segment into the at least one first slot up to at least one first region which includes a first exposed end portion; and inserting the at least one second winding segment into the at least one second slot up to at least one second region which includes a second exposed end portion. 
         [0010]    In addition, the method may also include retaining the first end portion as a result of inserting the first end portion into a first recess of a first bending device and as a result of positioning a first retaining element into a locking position in the first recess, and retaining the second end portion as a result of inserting the second end portion in a second recess of the first bending device. The method also includes bending the first and the second region in a first bending direction about a first bending angle as a result of rotating the first bending device about a rotational axis concentrically with respect to the laminated core, whilst the first and the second end portions are retained. Additionally, the method includes releasing the first end portion as a result of moving the first retaining element from the locking position into an unlocking position, and moving the second region further in the first bending direction about a second bending angle once the first end portion has been released. 
         [0011]    Implementations of the disclosure may include one or more of the following optional features. In some implementations, a known type of laminate core is provided accordingly for producing a winding carrier. The laminated core includes at least one first slot for receiving at least one first winding segment of the winding and at least one second slot for receiving at least one second winding segment of the winding. In this case, the at least one first and the at least one second slots are arranged along a first “virtual” circle or another closed line that is concentric with respect to the laminated core or is aligned centrally with respect to the laminated core. 
         [0012]    The winding segments are, for example, the legs of the afore-named hairpin-shaped winding pins or straight wires formed in a rod-shaped manner produced from metal or metal alloy, such as, but not limited to, copper or copper alloy, which are inserted into the named slots for forming windings. 
         [0013]    In some implementations, the at least one first winding segment is inserted into the at least one first slot for forming the winding with the exception of a first region. The first region projects out of the laminated core and includes a first exposed end portion. In an analogous manner, the at least one second winding segment is inserted into the at least one second slot for forming the winding with the exception of a second region. The second region projects out of the laminated core and includes a second exposed end portion. 
         [0014]    In some examples, if the winding segments are realized as legs of hairpin-shaped winding pins, they are thus inserted, having been interlocked and cranked beforehand in the manner described at the beginning of the description, into the corresponding slots up to in each case an exposed region. 
         [0015]    In some examples, if the winding segments are realized, in contrast, as rod-shaped straight wires, they are thus initially inserted into the corresponding slots up to in each case two exposed regions and are then interlocked at the respective two end regions. 
         [0016]    In some implementations, the first end portion of the first region is inserted in a first recess of a first bending device and is retained in the first recess as a result of positioning a first retaining element in a locking position. A second exposed end portion of the second region may also be inserted in a second recess of the first bending device and may be retained by the second recess. 
         [0017]    Whilst the first and the second end portions are retained, the first bending device is rotated concentrically with respect to the laminated core about a rotational axis. 
         [0018]    As a result, the first and the second regions are bent about a first bending angle in a first bending direction. Generally speaking, the bending device and the laminated core are rotated toward one another. Consequently, the laminated core may also be rotated in relation to the bending device. 
         [0019]    The first end portion may then be released as a result of moving or sliding or rotating (pivoting) the first retaining element from the locking position into an unlocking position. The second end portion, in contrast, may continue to be retained (i.e. is not released with the first retaining element). 
         [0020]    In some examples, once the first end portion has been released, the second region is bent further about a second bending angle in the first bending direction. 
         [0021]    The retaining elements may serve for the purpose of bending at least one selected end portion of all the end portions less strongly than the others. The selected end portions are released after a first bending step, whilst the others are bent further. 
         [0022]    Using the named method, a winding carrier with winding segments is consequently produced where the winding segments may be interlocked at various bending angles in a simple and cost-efficient manner. The first winding segments, which are each bent at the first smaller bending angle, consequently include end portions that protrude in the axial direction of the laminated core beyond the end portions of the second winding segments. Consequently, the end portions of the first winding segments, which are provided for forming the electric connection to external components such as, for example, the power source or the control device, are able to be connected electrically to the external components in a simple manner. 
         [0023]    As a result of realizing the method in simple method steps such as, for example, retaining, bending, releasing and bending further, a simple method is provided which may be realized without expensive tools or machines. 
         [0024]    A method, by way of which a winding of a winding carrier and consequently also an electric machine are producible in a cost-efficient and simple manner, is consequently created. 
         [0025]    According to a preferred development of the previously named method, a laminated core is provided which, along with the at least one first slot and the at least one second slot, also includes at least one third slot for receiving at least one third winding segment of the winding and at least one fourth slot for receiving at least one fourth winding segment of the winding. In this case, the at least one third slot and the at least one fourth slot are arranged along a second circle which is concentric with respect to the laminated core. 
         [0026]    In some examples, the at least one third winding segment is inserted into the at least one third slot for forming the winding with the exception of a third region, the third region projecting out of the laminated core by way of a third exposed end portion. In an analogous manner, the at least one fourth winding segment may be inserted into the at least one fourth slot for forming the winding with the exception of a fourth region, the fourth region may also project out of the laminated core by way of a fourth exposed end portion. 
         [0027]    The third exposed end portion of the third region may be retained as a result of introduction into a third slot of a second bending device and as a result of positioning a second retaining element in a locking position in the third recess. In an analogous manner, the fourth exposed end portion of the fourth region may be retained as a result of introduction into a fourth recess of the second bending device. 
         [0028]    Whereas the third and the fourth end portions are retained, the third and the fourth regions are bent about a third bending angle as a result of rotating the second bending device about the rotational axis concentrically with respect to the laminated core in a second bending direction, which is opposite to the first bending direction. 
         [0029]    The third end portion of the third region is then released as a result of moving or sliding the second retaining element from the locking position into an unlocking position and consequently no longer continues to be retained. The fourth end portion of the fourth region, in contrast, continues to be retained in or by the fourth recess. Once the third end portion has been released, the fourth region is bent further in the second bending direction about a fourth bending angle. 
         [0030]    According to a further preferred development of the afore-described method, the first, the second, the third and the fourth regions are bent substantially at the same time about the first or the third bending angles during the first bending operation. The second and the fourth regions are preferably also bent at substantially the same time about the second or the fourth bending angles during the further bending operation. 
         [0031]    As a result of carrying out the above-named bending operations at the same time, the forces, which act on the first, second, third and fourth regions during the bending operations, act on the laminated core in mutually opposite directions and are mutually compensated at the laminated core such that, in a comparative manner, a comparatively smaller additional force is necessary to retain the laminated core in a non-rotatable manner during the named bending operations. 
         [0032]    Another aspect of the disclosure provides a device for producing a winding of a winding carrier of an electric machine. The device includes a retaining device that is set up for retaining a laminated core together with at least one first and at least one second winding segment concentrically with respect to a rotational axis. In addition, the device includes a bending device which includes at least one first recess for receiving and for retaining a first exposed end portion of the at least one first winding segment and at least one second recess for receiving and for retaining a second exposed end portion of the at least one second winding segment. The first and the second recesses may be arranged open toward the retaining device and concentrically with respect to the rotational axis on a “virtual” circle. The bending device, in this case, is mounted so as to be rotatable about the rotational axis in relation to the retaining unit. 
         [0033]    In addition, the device includes at least one retaining element for retaining the first end portion. The retaining element may be arranged in the at least one first recess so as to be slidable or rotatable or both slidable and rotatable in relation to the at least one first recess between a locking position, in which the at least one retaining element retains the first end portion, and an unlocking position, in which the at least one retaining element releases the first end portion. 
         [0034]    Accordingly, a device is created which includes components, such as, for example, a retaining device with recesses or a retaining element, which may be produced in a simple and cost-efficient manner. Using the components, the device is able to produce winding carriers in the simple afore-described method steps with variously bent winding segments in a cost-efficient manner. 
         [0035]    In some implementations, the at least one first recess includes a side wall which is set up for retaining, with the at least one retaining element which is situated in the locking position, the first end portion of the first winding pin. 
         [0036]    All or groups of retaining elements are preferably actuated jointly by means of a mechanical and/or electric connection. An actuator that moves the retaining elements individually or jointly is provided. 
         [0037]    In some implementations, the device additionally includes an actuator device which is set up for moving, for example sliding or rotating or both sliding and rotating, the at least one retaining element between the locking and the unlocking positions. 
         [0038]    The actuator device includes the afore-named actuator that, generally speaking, is able to generate a movement that is transmitted to the retaining elements. The actuator may also generate a movement by way of which the retaining elements are rotated. 
         [0039]    Another aspect of the disclosure provides the device that includes a rotating and sliding device which is set up for rotating the bending device about the rotational axis and in relation to the retaining device and/or for sliding it in the direction of the rotational axis in relation to the retaining device. 
         [0040]    Advantageous developments of the above-shown method, insofar as otherwise transferrable to the above-mentioned device, are also to be seen as advantageous developments of the device. In an analogous manner, advantageous developments of the above-described device, insofar as otherwise transferrable to the above-described method, are also to be seen as advantageous developments of the method. 
         [0041]    The details of one or more implementations of the disclosure are set forth in the accompanying drawings and the description below. Other aspects, features, and advantages will be apparent from the description and drawings, and from the claims. 
     
    
     
       DESCRIPTION OF DRAWINGS 
         [0042]      FIG. 1  shows a schematic representation of a view from below of an exemplary laminated core. 
           [0043]      FIG. 2  shows a schematic representation of an exemplary oblique top view of a stator together with the laminated core shown in  FIG. 1 . 
           [0044]      FIG. 3  shows a schematic representation of a side view of an exemplary device for producing the stator shown in  FIG. 2 . 
           [0045]      FIG. 4  shows a schematic flow chart of an exemplary method for producing the stator shown in  FIG. 2 . 
           [0046]      FIGS. 5A-5F  show respective schematic representations of respective side views of the exemplary device shown in  FIG. 3  and of intermediate products of the stator shown in  FIG. 2  when it is being produced after each method step according to the method shown in  FIG. 4 . 
       
    
    
       [0047]    Like reference symbols in the various drawings indicate like elements. 
       DETAILED DESCRIPTION 
       [0048]      FIG. 1  shows a view from below of a laminated core BP for forming a stator ST of an electric machine. The laminated core BP is realized in a hollow-cylindrical form running around an axis AS. On an inside wall IW facing the axis AS, the laminated core BP includes a group of grooves NT (including NT 1 , NT 2 ) which. When the group of grooves NT viewed from the axis AS, the group of grooves NT are arranged as radial indentations which are distributed uniformly along the inside wall IW of the laminated core BP and extend in the direction of the axis AS from a bottom end UE of the laminated core BP, which is located facing the observer of the Figure, to a top end OE of the laminated core BP which is oppositely situated to the bottom end UE (compare with  FIG. 2 ). 
         [0049]    In some implementations, a layer of insulation paper IS, which serves for the electric insulation between the laminated core BP and windings pins WP which are to be described below, is arranged in each case on the inside walls of the respective grooves NT. When viewed in the direction of the axis AS, the insulating paper layer IS may be in the form of an S or an 8. The insulating paper layer IS may consequently divides each of the grooves NT into two areas that extend in parallel from the bottom end UE to the top end OE of the laminated core BP. Proceeding from the axis AS when viewed radially, the two areas of the respective grooves NT are located one behind the other. On account of the narrow, elongated form, the two areas are referred to below as slots, in each case the area of the respective grooves NT facing the axis AS being referred to as the inside slot SLI and the area of the respective grooves NT remote from the axis AS being referred to as the outer slot SLA. 
         [0050]    When viewed in the direction of the axis AS, the outer slots SLA or the centers of gravity or area center points thereof are situated along a first “virtual” circle KS 1  having a first circle center point KM 1 . In an analogous manner, the inner slots SLI or the centers of gravity or area center points thereof, when viewed in the direction of the axis AS, are situated along a second “virtual” circle KS 2  having a second circle center point KM 2 . The first and the second circle KS 1  and KS 2 , in this case, form two circles that are concentric with respect to one another and with respect to the axis AS. Consequently, the circle center points KM 1 , KM 2  overlap one another and the axis AS when viewed in the direction of the axis AS. 
         [0051]    In some examples, to form windings, winding pins WP—also referred to as winding rods—produced from copper alloy are inserted into the grooves NT. In this case, the winding pins WP may be pre-bent in a hairpin-shaped or U-shaped manner and include one first leg SK 1  and one second leg SK 2  each. Prior to insertion into the grooves NT, the winding pins WP are interlocked and cranked in a manner known to the expert by way of an expanding step via a winding pitch of a stator ST, which is to be described below, such that the two legs SK 1 , SK 2 , which are cranked in relation to one another, of every individual winding pin WP are inserted, corresponding to the winding pitch of the laminated core BP, in each case into an outer slot SLA of a first groove NT 1  and into an inner slot SLI of a second groove NT 2  which is located at a spacing from the first groove NT 1  corresponding to the winding pitch of the stator ST, as is illustrated as an example in  FIG. 1  with a winding pin WP. In this case, the two legs of each individual winding pin WP realize one winding segment each of the windings WL. 
         [0052]    Reference is now made to  FIG. 2  that shows a schematic representation of an oblique top view of a stator ST or a laminated core BP of a stator ST with installed windings WL. In some implementations, the stator ST includes a laminated core BP shown in  FIG. 1  and a number of winding pins WP that are inserted into the respective grooves NT in the afore-described manner. In this case, the winding segments P 1 , P 2 , P 3 , and P 4  of the winding pins WP are inserted into the respective grooves NT in such a manner that they each include a region B 1 , B 2 , B 3  and B 4  which projects out of the top end OE of the laminated core BP. To form windings WL, the regions B 1 , B 2 , B 3 , and B 4  of the respective winding segments P 1 , P 2 , P 3 , and P 4  are interlocked with one another in a manner to be described below corresponding to the winding pitch of the stator ST and are connected together electrically. 
         [0053]    In some examples, to form windings WL, the winding segments P 1 , P 2  inserted into the outer slots SLA or the regions B 1 , B 2  thereof projecting out of the laminated core BP are bent in a first bending direction BR 1 , which corresponds to a first circumferential direction UR 1  of the first circle KS 1 . The parts may be bent about an identical bending angle BW 1 +BW 2  with the exception of a few selected winding segments P 1 . 
         [0054]    The selected winding segments P 1  may be bent about a bending angle BW 1  that deviates from the previously named bending angle BW 1 +BW 2  (compare with  FIG. 5E ). The selected winding segments P 1 , which are referred to as first winding segments below, serve for forming an electric connection between the windings WL and an external power source or control device not shown in the Figure. The outer slots SLA, in which the first winding segments P 1  are inserted, are referred to below as first slots SL 1 . The regions B 1  of the first winding segments P 1  projecting out of the laminated core BP are correspondingly referred to as first regions. The first regions B 1  include in each case a first exposed end portion E 1  that is realized protruding in the direction of the axis AS. 
         [0055]    The remaining winding segments P 2 , which are bent about the identical bending angle BW 1 +BW 2 , are referred to below as second winding segments. The outer slots SLA in which the second winding segments P 2  are inserted are referred to below as second slots SL 2 . The regions B 2  of the second winding segments P 2  protruding out of the laminated core BP are referred to below analogously as second regions. The second regions B 2  include in each case a second exposed end portion E 2  that is also realized protruding in the direction of the axis AS. 
         [0056]    In an analogous manner, the winding segments P 3 , P 4  inserted into the inner slots SLI or the regions B 3 , B 4  thereof projecting out of the laminated core BP are bent in a second bending direction BR 2 , which is opposite to the first bending direction BR 1  and corresponds to a second circumferential direction UR 2  of the second circle KS 2 . In this case, winding segments P 4  are also bent about an identical bending angle BW 3 +BW 4  with the exception of a few selected winding segments P 3 . 
         [0057]    The selected winding segments P 3 , analogously to the previously named first winding segments P 1 , are bent about a bending angle BW 3  which deviates from the last named bending angle BW 3 +BW 4  (compare with  FIG. 5E ). The selected winding segments P 3  also serve for forming the electric connection between the windings WL and the external power source or control device and are referred to below as third winding segments. The inner slots SLI, in which the third winding segments P 3  are situated, are referred to below as third slots SL 3 . The regions B 3  of the third winding segments P 3  projecting out of the laminated core BP are correspondingly referred to as third regions. The third regions B 3  include in each case a third exposed end portion E 3  that is realized protruding in the direction of the axis AS. 
         [0058]    The remaining winding segments P 4  that are bent about the identical bending angle BW 3 +BW 4  are referred to below as fourth winding segments. The inner slots SLI in which the fourth winding segments P 4  are inserted are referred to below as fourth slots SL 4 . The regions B 4  of the fourth winding segments P 4  protruding out of the laminated core BP are referred to below analogously as fourth regions. The fourth regions B 4  include in each case a fourth exposed end portion E 4  that is realized protruding in the direction of the axis AS. 
         [0059]    In some implementations, for forming windings WL, the second end portion E 2  of each individual second winding segment P 2  is connected electrically in a manner to be described below to a fourth end portion E 4  of each fourth winding segment P 4 , which is arranged at a spacing from the second winding segment P 2  corresponding to the winding pitch of the stator BP. 
         [0060]    The first and the third end portions E 1 , E 3  are connected electrically to the external power source or control device by means of the electric connection not shown in the Figure. In this case, the first and the third end portions E 1 , E 3  project beyond the plane of the second and fourth end portions E 2  and E 4  in the axial direction. 
         [0061]    The manner in which the regions B 1 , B 2 , B 3 , and B 4  of the winding segments P 1 , P 2 , P 3 , and P 4  are bent at various bending angles B 1 , BW 1 +BW 2 , B 3 , or BW 3 +BW 4  is described below as an example. 
         [0062]    Reference is now made to  FIG. 3 , which shows a schematic representation of a side view of a device V for producing the stator ST shown in  FIG. 2  or for bending the regions B 1 , B 2 , B 3  and B 4  of the winding segments P 1 , P 2 , P 3  and P 4 . In this case, the components of the device are shown axially offset from one another in a similar manner to an exploded drawing. 
         [0063]    In some examples, the device V includes a retaining device HE for retaining the previously described laminated core BP together with the winding pins WP that are inserted into the grooves NT. The retaining device HE is realized in the form of a hollow cylinder that runs around an axis AS 1  and consequently borders a cylinder-shaped interior ZI that is realized concentrically with respect to the retaining device HE. On the side face SF, which is shaped as a cylinder lateral surface and faces the interior ZI, the retaining device HE includes a number of latching elements RE which, when the laminated core BP is arranged in the interior ZI, latch into corresponding indentations (not shown in the Figure) on the outside wall of the laminated core BP in a manner known to the expert and consequently fix the laminated core BP in a non-movable, in particular non-rotatable manner, concentrically with respect to the axis AS 1 . If the laminated core BP is fixedly fixed in the interior ZI of the retaining device HE, the axis AS 1  of the retaining device HE and the axis AS of the laminated core BP overlap. 
         [0064]    The device V may additionally include a first bending device BE 1  which is realized in the shape of a hollow cylinder and concentrically with respect to the retaining device HE and consequently to the axis AS 1  of the retaining device HE. When viewed in the direction of the axis AS 1 , the first bending device BE 1  is arranged offset from the retaining unit HE and is realized so as to be rotatable about the axis AS 1  and in relation to the retaining device HE. 
         [0065]    On a bottom surface US 1  facing the retaining device HE, the first bending device BE 1  may include a number of recesses AN 1 , AN 2 , which correspond in number to the number of grooves NT and consequently to the number of outer slots SLA of the previously described laminated core BP and may be arranged so as to be open toward the retaining device HE and distributed along a circle concentrically with respect to the axis A 1 . 
         [0066]    In some examples, the recesses AN 1 , AN 2  serve (as receiving pockets) for receiving and retaining the first and the second end portions E 1 , E 2  of the respective first and second winding segments P 1 , P 2 . In this case, the recesses AN 1 , AN 2  include two different forms. First recesses AN 1 , which form a small group of recesses AN 1 , AN 2 , include in each case a cavity that extends continuously from the bottom surface US 1  of the first retaining device HE 1  to a top surface OS 1  of the first retaining device HE 1  that is located remotely from the bottom surface US 1 . The cavity, when viewed radially with respect to the axis AS 1 , includes a cross section that is realized tapering in steps from the bottom surface US 1  toward the top surface OS 1 . In this case, the cavity includes three areas with different—with reference to the axis AS 1 —radial cross sectional areas. 
         [0067]    In some implementations, the area that is located facing the bottom surface US 1  of the first bending device BE 1 , which is referred to below as the first area RB 1 , includes a cross sectional area that is the largest compared with the remaining two areas. 
         [0068]    The area that is located facing the top surface OS 1  of the first bending device BE 1 , which is referred to below as the third area RB 3 , includes a cross sectional area that is the smallest compared with the remaining two areas. The area that is located between the first and the second areas RB 1 , RB 3 , which is referred to below as the second area RB 2 , includes a cross sectional area which has surface area between the cross section areas of the first and of the third areas RB 1 , RB 3 . This is illustrated in an enlarged section A of the first bending device BE 1  in  FIG. 3 . 
         [0069]    In some examples, a larger group of remaining recesses forms in each case a cuboid-shaped cavity, the cross section of which located perpendicular to the axis AS 1  corresponds to the respective cross section of the second end portion E 2  of the respective corresponding second winding segment P 2 . This makes it possible for the respective second end portions E 2  to be received into the respective corresponding recesses. The recesses of the group are referred to below as second recesses AN 2 . 
         [0070]    The device V may include a group of first retaining elements FE 1  for retaining the first end portions E 1  of the respective first winding segments P 1 . The first retaining elements FE 1  may be realized in an L-shaped manner and include in each case a rod-shaped basic body GK, a head region KB with an enlarged cross sectional area at one end of the basic body GK and a base region SB at another end of the basic body GK. 
         [0071]    In some examples, the first retaining elements FE 1  are realized so as to be slidable in the respective first recesses AN 1  in the direction of the axis AS 1  between a locking position PS 1  (see section B in  FIG. 3 ) and an unlocking position PS 2  (see section C in  FIG. 3 ). 
         [0072]    In this case, the basic bodies GK of the respective first retaining elements FE 1  include in each case a cross sectional area which corresponds to the cross sectional area of the third region RB 3  of the respective first recesses AN 1 , which makes it possible for the basic body GK of the respective first retaining elements FE 1  to be received into the third region RB 3  of the respective first recesses AN 1  and the respective retaining elements FE 1  to be slid in the direction of the axis AS 1  in the respective first recesses AN 1 . 
         [0073]    In some examples, the head regions KB of the respective first retaining elements FE 1  include in each case a cross sectional area which corresponds to the cross sectional area of the second region RB 2  of the respective first recesses AN 1 . This makes it possible for the head region KB of the respective first retaining elements FE 1  to be received into the respective second area RB 2  of the respective first recesses AN 1  when the respective first retaining elements FE 1  are slid from the respective locking positions PS 1  and into the respective unlocking positions PS 2 . 
         [0074]    If the first retaining elements FE 1  are situated in the respective locking positions PS 1 , the head regions KB of the respective first retaining elements FE 1  fill the first areas RB 1  of the respective first recesses AN 1  in such a manner that cavities are formed between the respective first retaining elements FE 1  and the respective corresponding first recesses AN 1 , the cross sectional areas of which cavities correspond to the cross sectional area of the first end portions E 1  of the respective first winding pins P 1  which are received and retained in the corresponding recesses AN 1 . 
         [0075]    The device V additionally includes a first actuator device SE 1  for sliding the first retaining elements FE 1  between the locking position PS 1  and the unlocking position PS 2 . 
         [0076]    The first actuator device SE 1  may be realized in the shape of a hollow cylinder and concentrically with respect to the first bending device HE 1  and consequently to the axis AS 1  of the retaining unit HE. In some examples, the first actuator device SE 1  is realized so as to be non-rotatable with respect to the first bending device BE 1  and consequently so as to be synchronously rotatable with the first bending device BE 1  in the circumferential direction thereof and so as to be axially slidable in the direction of the axis AS 1  and in relation to the first bending device BE 1 , the first actuator device SE 1  sliding the first retaining elements FE 1  between the locking and the unlocking positions PS 1 , PS 2  as a result of its axial movement. The first actuator device SE 1  may include an actuator that moves the first retaining elements FE 1  between the two positions PS 1 , PS 2 . 
         [0077]    In some implementations (not shown), the first retaining elements FE 1  are rotatably mounted in the respective first recesses AN 1  and have in each case an eccentric head region which can be rotated by an actuator of the first actuator device SE 1  between a locking position and an unlocking position. 
         [0078]    In some examples, the device V additionally includes a first rotating and sliding device DE 1  that is realized for rotating the first bending device BE 1  and the first actuator device SE 1  in a synchronous manner with respect to one another and in relation to the retaining device HE. The first rotating and sliding device DE 1  may be additionally realized for sliding the first bending device BE 1  and the first actuator device SE 1  axially in relation to the retaining device HE. In addition, the first rotating and sliding device DE 1  may be realized for sliding the first actuator device SE 1  axially in relation to the first bending device BE 1 . 
         [0079]    The device V may additionally include a second bending device BE 2  which is also realized in the shape of a hollow cylinder and concentrically with respect to the retaining device HE and consequently to the axis AS 1 . The second bending device BE 2 , when viewed in the direction of the axis AS 1 , may be arranged offset from the retaining unit HE and is realized so as to be rotatable about the axis AS 1  and in relation to the retaining device HE. 
         [0080]    In some examples, on a bottom surface facing the retaining device HE, the second bending device BE 2  includes the same number of recesses AN 3 , AN 4  as that of the first bending device BE 1 , which are arranged so as to be open toward the retaining device HE and distributed along a circle concentrically with respect to the axis A 1 . The recesses AN 3 , AN 4  serve analogously to the first and the second recesses AN 1 , AN 2  (as receiving pockets) for receiving and for retaining the end portions E 3 , E 4  of the respective corresponding third and fourth winding segments P 3 , P 4 . In this case, the recesses AN 3 , AN 4  also include two different forms. In some examples, recesses which realize a smaller group and are referred to below as third recesses AN 3  serve for retaining the third end portions E 3  of the third winding segments P 3  and are realized in each case substantially mirror-symmetrically with respect to the respective first recesses AN 1 . In some examples, recesses that realize a larger group and serve for retaining the fourth end portions E 4  of the fourth winding segments P 4  are realized in each case substantially mirror-symmetrically with respect to the respective second recesses AN 2 . Recesses of the larger group are referred to below as fourth recesses AN 4 . 
         [0081]    In some implementations, the device V additionally includes a group of second retaining elements FE 2  for retaining the third end portions E 3  of the respective third winding segments P 3 . The second retaining elements FE 2  are realized substantially mirror-symmetrically with respect to the respective first retaining elements FE 3  and are arranged in a similar manner to the first retaining elements FE 1  so as to be slidable in the respective third recesses AN 3  between a locking position PS 3  and an unlocking position PS 4  (compare with  FIGS. 5A to 5E ). 
         [0082]    In some examples, the device V additionally includes a second actuator device SE 2  for sliding the second retaining elements FE 2  between the locking position PS 3  and the unlocking position PS 4 . 
         [0083]    The second actuator device SE 2  may be realized in the shape of a hollow cylinder and concentrically with respect to the second bending device HE 2  and consequently to the axis AS 1 . In some examples, the second actuator device SE 2  is realized analogously to the first actuator device SE 1  so as to be non-rotatable with respect to the second bending device BE 2  and consequently so as to be synchronously rotatable with the second bending device BE 2  in the circumferential direction thereof and so as to be axially slidable in the direction of the axis AS 1  in relation to the second bending device BE 2 . 
         [0084]    In some implementations, the device V additionally includes a second rotating and sliding device DE 2  that is realized for rotating the second bending device BE 2  and the second actuator device SE 2  in a synchronous manner with respect to one another and in relation to the retaining device HE. The second rotating and sliding device DE 2  may be additionally realized for sliding the second bending device BE 2  and the second actuator device SE 2  axially in relation to the retaining device HE. In addition, the second rotating and sliding device DE 2  is realized for sliding the second actuator device SE 2  axially in relation to the second bending device BE 2 . 
         [0085]    After describing the device V for producing the windings WL of the stator ST in detail, a method for producing the windings WL is described in more detail by way of  FIGS. 4 and 5A to 5F . In this case,  FIG. 4  shows the sequence of the method in a schematic flow chart.  FIGS. 5A to 5F  show the device V and the stator ST or the intermediate products thereof prior to, during and after respective method steps, in each case schematic side views of portions of the stator ST or of the intermediate products thereof and of the device V and of the components thereof being shown after respective method steps. 
         [0086]    To produce the windings WL of the stator ST shown in  FIG. 2 , a laminated core BP shown in  FIG. 1  is provided according to a first method step S 100 . The laminated core BP is assembled from a number of metal disks punched from a metal rail in a manner known to the expert. In this case, the metal disks are punched such that, on the inside wall IW that is shaped as a cylinder lateral surface, the assembled laminated core BP includes a number of grooves NT, corresponding to the winding pitch of the stator ST, which extend in the direction of the axis AS of the laminated core BP. Layers of insulation paper IS are arranged in the respective grooves NT, the layers, when viewed in the direction of the axis AS of the laminated core BP, being formed in the shape of an S or an 8 and consequently dividing the respective grooves NT in each case into one outer and one inner slot SLA, SLI, the outer slots SLA including the afore-mentioned first and second slots SL 1 , SL 2  and the inner slots SLI including the afore-mentioned third and fourth slots SL 3 , SL 4 . 
         [0087]    According to a further method step S 200 , the previously described first, second, third, and fourth winding segments P 1 , P 2 , P 3 , and P 4  of the winding pins WP, which have previously been interlocked and cranked beforehand in a manner known to the expert by way of an expanding step corresponding to the winding pitch of the stator ST, are inserted into the first, second, third and fourth slots SL 1 , SL 2 , SL 3  and SL 4 . In this case, the winding segments P 1 , P 2 , P 3 , and P 4  are inserted in such a manner into the respective slots SL 1 , SL 2 , SL 3 , and SL 4  that in each case a first, second, third and fourth region B 1 , B 2 , B 3 , and B 4  of the winding segments P 1 , P 2 , P 3 , and P 4  projects out of the laminated core BP in each case by way of a first, second, third, and fourth exposed end portion E 1 , E 2 , E 3 , and E 4 . The first and the second winding segments P 1 , P 2  in the respective first and second slots SL 1 , SL 2  of the respective grooves NT and the third and the fourth winding segments P 3 , P 4  in the corresponding third and fourth slots SL 3 , SL 4  of the identical grooves NT are electrically insulated from one another and from the laminated core BP by means of the insulation paper layers IS. 
         [0088]    In some examples, to form windings WL, the second winding segments P 2  of the winding pins WP are directly connected electrically to the respective fourth winding segments P 4  of the winding pins WP that are arranged offset to the winding pins WP corresponding to the winding pitch of the stator ST. To this end, the second and fourth winding segments P 2 , P 4 , which correspond to one another, are bent toward one another in each case by a predetermined bending angle. The first and the third winding segments P 1 , P 3  are connected electrically to the external power source. To this end, the first and the third winding segments P 1 , P 3  are bent in each case by a bending angle that deviates from the bending angle of the second and the fourth winding segments P 2 , P 4 . 
         [0089]    To this end, the laminated core BP together with the inserted winding pins WP is non-rotatably retained by the retaining device HE concentrically with respect to the retaining device HE, as is illustrated in  FIG. 5A . 
         [0090]    The first and the second bending devices BE 1 , BE 2  as well as the first and the second actuator devices SE 1 , SE 2  are then driven, according to a method step S 300 , by the first and the second rotating and sliding devices DE 1 , DE 2  in the direction toward the retaining device HE and are consequently lowered toward the laminated core BP, the second and the fourth end portions E 2 , E 4  being received and retained by the respective second and fourth recesses AN 2 , AN 4 . The first and the third end portions E 1 , E 3  are also received by the respective first and third recesses AN 1 , AN 3 . The first and the second retaining elements FE 1 , FE 2 , in this case, are positioned in the respective locking positions PS 1 , PS 3  by the first and the second actuator devices SE 1 , SE 2 . In the locking positions PS 1 , PS 3 , the first and the second retaining elements FE 1 , FE 2 , with the respective corresponding side walls SW of the respective first and third recesses AN 1 , AN 3 , fix the respective first and third end portions E 1 , E 3  such that they, as the second and the fourth end portions E 2 , E 4 , are non-movably retained (compare with  FIG. 5B ). 
         [0091]    Whilst the end portions E 1 , E 2 , E 3 , E 4  are retained in the respective recesses AN 1 , AN 2 , AN 3 , AN 4 , according to a further method step S 400 , the first bending device BE 1 , driven by the first rotating and sliding device DE 1  together with the first actuator device SE 1 , is rotated about a first angle of rotation in a first rotational direction DR 1 , which is at the same time the first circumferential direction UR 1  of the previously described first circle KS 1 . In this case, the first bending device BE 1 , driven by the first rotating and sliding device DE 1  together with the first actuator device SE 1 , is lowered axially in the direction of the retaining device HE and consequently of the laminated core BP. As a result of the rotating and sliding movement of the first bending device BE 1  in relation to the laminated core BP, the first and the second regions B 1 , B 2  of the respective first and second winding segments P 1 , P 2 , when viewed radially, are all bent about a first bending angle BW 1  in the first bending direction BR 1  (compare with  FIG. 5C ). 
         [0092]    At the same time, according to the method step S 400 , the second bending device BE 2 , driven by the second rotating and sliding device DE 2  together with the second actuator device SE 2 , is rotated about a third angle of rotation in a second rotational direction DR 2  that is opposite to the first rotational direction DR 1 . In this case, the second bending device BE 2 , driven by the second rotating and sliding device DE 2  together with the second actuator device SE 2 , is lowered axially in the direction of the retaining device HE and consequently of the laminated core BP. As a result of the rotating and sliding movement of the second bending device BE 2  in relation to the laminated core BP, the third and the fourth regions B 3 , B 4  of the respective third and fourth winding segments P 3 , P 4 , when viewed radially, are all bent about a third bending angle BW 3  in the second bending direction BR 2  which faces the first bending direction BR 1  (compare with  FIG. 5C ). 
         [0093]    After the first bending operation according to the method step S 400 , according to a further method step S 500 , the first and the second actuator devices SE 1 , SE 2  are slid in the axial direction away from the first and the second bending devices BE 1 , BE 2  and consequently away from the laminated core BP. As a result of sliding the first and the second actuator devices SE 1 , S 5 E 2  away from the laminated core BP, the first and the second retaining elements FE 1 , FE 2  are slid from the respective locking positions PS 1 , PS 3  into the respective unlocking positions PS 2 , PS 4 . As a result, the first and the third end portions E 1 , E 3  are no longer retained by the first and the second retaining elements FE 1 , FE 2  or in the first and the third recesses AN 1 , AN 3  (compare with  FIG. 5D ). 
         [0094]    The first bending device BE 1 , according to a further method step S 600 , driven by the first rotating and sliding device DE 1  together with the first actuator device SE 1  is then rotated further in the first rotational direction DR 1  about a second angle of rotation. The first bending device BE 1  and the first actuator device SE 1 , driven by the first rotating and sliding device DE 1 , are lowered further axially in the direction of the retaining device HE and consequently of the laminated core BP. As a result of the first bending device BE 1  rotating and moving further axially in relation to the laminated core BP, the second regions B 2  of the respective second winding segments P 2  are bent further in the first bending direction BR 1  about a second bending angle BW 2  and consequently are bent further in total by up to a bending angle of BW 1 +BW 2  (compare with  FIG. 5E ). 
         [0095]    At the same time, according to the method step S 600 , the second bending device BE 2 , driven by the second rotating and sliding device DE 2  together with the second actuator device SE 2 , is rotated further about a fourth angle of rotation in the second rotational direction DR 2 . The second bending device BE 2  and the second actuator device SE 2 , driven by the second rotating and sliding device DE 2 , being lowered further axially in the direction of the retaining device HE and consequently of the laminated core BP. As a result of the rotating and sliding movement of the second bending device BE 2  in relation to the laminated core BP, the fourth regions B 4  of the respective fourth winding segments P 4  are bent further about a fourth bending angle BW 4  in the second bending direction BR 2  and consequently are bent further in total by up to a bending angle of BW 3 +BW 4 (compare with  FIG. 5E ). 
         [0096]    After the second bending operation according to the method step S 600 , according to a further method step S 700 , the second end portions E 2  of the respective second winding segments P 2  and the corresponding fourth end portions E 4  of the fourth winding segments P 4 , which are located at a spacing from the second winding segments P 2  corresponding to the winding pitch of the stator ST, are directly connected together electrically and mechanically after a welding operation by means of a respective welded joint SV. The first and the third end portions E 1 , E 3  of the respective first and third winding segments P 1 , P 3  are directly connected together electrically in a further welding operation with metal webs or jumper wires MB which produce electric connections between the windings WL and the external power source or control device (compare with  FIG. 5F ). 
         [0097]    Rod-shaped straight wire produced from copper alloy may be used as winding segments in place of the hairpin-shaped winding pins. In some examples, the winding segments have two exposed end regions at the respective oppositely situated ends, and are first of all inserted into the corresponding slots of the laminated core and are then interlocked at the respective two end regions. 
         [0098]    In each case a first of the two end regions of the respective winding segments which are arranged in a first and the same concentric row, which first end region is situated on the same side of the laminated core, is bent at a bending angle and electrically connected to an end region of a winding segment, which is arranged at a spacing corresponding to the winding pitch in a second concentric row and has also been bent at a bending angle. 
         [0099]    Second end regions of the respective winding segments, which are located on the oppositely situated side of the laminated core, are bent at various bending angles in the manner described in conjunction with  FIG. 2  and are electrically connected in a corresponding manner to corresponding winding segments or to the external power source or control device. 
         [0100]    The device V described in conjunction with  FIG. 1  and the method described in conjunction with  FIG. 2  relate to a winding with a two-layered arrangement of winding segments where the winding segments are arranged distributed in two circles or rows that are concentric with respect to one another. The device V or the method may also be used to produce a winding with a three-layered or multiple-layered, in particular four-layered, arrangement of winding segments. Just simple modifications to the device or the method, which are able to be carried out without any problem by an expert, are needed for this purpose, such as, for example, as a result of additional bending devices with analogously realized recesses and retaining elements which just need to be realized or arranged concentrically with respect to the existing bending devices. 
         [0101]    A number of implementations have been described. Nevertheless, it will be understood that various modifications may be made without departing from the spirit and scope of the disclosure. Accordingly, other implementations are within the scope of the following claims.