Abstract:
A device for bending a plurality of winding segments to form a winding of a winding carrier of an electric machine is provided. The device includes: a holding device designed for holding in place the winding carrier in which the winding segments are arranged; a main bending device, including a number of main locking elements, which point towards the holding device, are arranged along first sections of a circumferential line and are designed to lock exposed end sections of first winding segments; and a partial bending device, including a number of partial locking elements, which point towards the holding device, are arranged along second sections of the circumferential line and are designed to lock exposed end sections of second winding segments. The holding device on the one hand and the main bending device and the partial bending device on the other hand are rotatable relative to each other.

Description:
TECHNICAL FIELD 
       [0001]    The present disclosure relates to an apparatus and to a method for bending a large number of winding segments for forming a winding of a winding support, that is to say a stator or a rotor, of an electrical machine. A winding support and an electrical machine including a winding support of said kind are also provided. 
       BACKGROUND 
       [0002]    Electrical machines have winding supports that have a laminated core, together with windings that are inserted into the laminated core, and are in the form of stators or rotors of the electrical machines. The windings may be formed from a large number of winding pins that are of hairpin-shaped or U-shaped design and each has two limbs as winding segments. 
         [0003]    In order to form windings, the two winding segments of the respective winding pin are interleaved and interlocked by a spreading step by means of a winding step of the winding support. As such, the two winding segments of each individual winding pin may be inserted into corresponding pole slots, which are provided for them, of the laminated core in line with the winding step of the winding support. 
         [0004]    Exposed regions, which protrude from the laminated core, of winding segments of most of the winding pins, which are provided for forming windings and are therefore directly electrically connected to exposed regions of winding segments of corresponding winding pins, which are arranged such that they are spaced apart in line with the winding step, are then interleaved and electrically connected to the corresponding, likewise interleaved, regions of the winding segments of the corresponding winding pins. 
         [0005]    Exposed regions of winding segments of the remaining, selected winding pins, which are further provided, in addition to the abovementioned function for forming windings, for interleaving the windings to form current phases or for establishing electrical connections from the windings to an external current source or a power electronics system by phase input or phase output, are otherwise interleaved and electrically connected to the external current lines. 
         [0006]    The bent bending regions of the winding segments then form a winding head of the winding support of the electrical machine. In order to construct an electrical machine such that as much installation space as possible is saved while retaining the same power density, the overall height of the winding head of the electrical machine has to be kept as small as possible. 
         [0007]    As an alternative, bar or I-like winding bars are also provided, said winding bars, unlike above-described winding pins, first being inserted into the corresponding pole slots as far as in each case two exposed end regions and then being interleaved at the respective two end regions. Therefore, both the winding pins and also the winding bars form plug-type windings. 
         [0008]    As is customary in the case of technical components, there is additionally a general requirement in electrical machines for said electrical machines to be produced as far as possible in a cost-effective manner using a simple production process. In particular, this requirement is very important in the automotive sector. 
       SUMMARY 
       [0009]    Consequently, the object of the present disclosure is to provide a simple and cost-effective way of being able to produce a winding support and therefore an electrical machine in an installation space-saving manner. 
         [0010]    One aspect of the disclosure provides an apparatus for bending a large number of winding segments for forming a winding or a plug-type winding of a winding support, that is to say a stator or a rotor, of an electrical machine. The apparatus includes a holding device which is designed to firmly hold the winding support in which the winding segments are arranged. 
         [0011]    The apparatus further includes a main bending device. The main bending device includes a number of main locking elements which face the holding device. The main locking elements are arranged along first sections of a circumferential line which runs around an axis. The main locking elements are designed to lock exposed end sections of a first group of the winding segments. 
         [0012]    The apparatus further includes a partial bending device. The partial bending device includes a number of partial locking elements which likewise face the holding device. The partial locking elements may be arranged along second sections of the circumferential line and are designed to lock exposed end sections of a second group of the winding segments. 
         [0013]    Implementations of the disclosure may include one or more of the following optional features. In some implementations, the holding device on the one hand and the main bending device and the partial bending device on the other hand are designed such that they can rotate in relation to one another. By splitting the bending device into a main bending device and a partial bending device, it is possible to interleave or to bend the winding segments in accordance with their functions in such a way that they can be bent by the same ultimate bending angle in relation to the cross-sectional plane of the winding support but with different bending lengths. 
         [0014]    In some examples, the bending length means a length of a bending region of a winding segment, which bending region forms the bent section of the winding segment after the bending process on the winding segment. 
         [0015]    The same bending angle allows the winding segments to be able to be bent even further than winding segments with different bending angles. This in turn allows a low overall height for the winding head. 
         [0016]    Different bending lengths for the winding segments allow the winding segments, which are provided, depending on their functions, for forming windings or for establishing electrical connections with an external current source or a power electronics system, to be able to each be electrically connected to corresponding winding segments or to external current lines in a simple manner in a subsequent production phase of the winding support. 
         [0017]    In some implementations, owing to the design of the holding device on the one hand and the main bending device and the partial bending device on the other hand such that they may rotate in relation to one another, it is possible to rotate either the exposed end sections of the bending regions or of the winding segments with respect to the winding support or, conversely, to rotate the winding support with respect to the end sections and, in the process, to bend the winding segments. 
         [0018]    The abovementioned first and second sections of the circumferential line form regions of the circumferential line which are disjointed in relation to one another. Accordingly, the first and the second group of winding segments do not form an intersection set. In other words, a winding segment belongs either to the first group of winding segments or to the second group of winding segments. 
         [0019]    The apparatus may be produced in a simple and cost-effective manner per se. In addition, an apparatus of this kind is easy to operate. Consequently, the winding support and therefore also electrical machines including the apparatus may be produced in a simple, cost-effective and additionally installation space-saving manner. 
         [0020]    In some implementations, the holding device and the main bending device are designed such that they can rotate bidirectionally in relation to one another. 
         [0021]    Owing to the bidirectional rotation in relation to one another, the holding device and the main bending device may bidirectionally bend the first group of the winding segments. This may make it easier to interleave and/or bend the first and the second group of winding segments by the same ultimate bending angle but with different bending lengths, as described above. 
         [0022]    The holding device and the partial bending device are also preferably designed such that they may rotate bidirectionally in relation to one another. In some examples, the holding device and the partial bending device are designed such that they can rotate unidirectionally in relation to one another. 
         [0023]    Owing to the unidirectional rotation in relation to one another, the holding device and the partial bending device may only unidirectionally bend the second group of the winding segments. This has the advantage that the second group of winding segments, which are intended to be bent only in one bending direction in any case, are not incorrectly bent in an opposite, incorrect bending direction. 
         [0024]    In some examples, the circumferential line is in the shape of an ellipse, wherein the axis passes through the center of the ellipse. The circumferential line may be in the shape of a circle, where the axis passes through the center of the circle. 
         [0025]    The main locking elements and/or partial locking elements may be in the form of gripping elements or in the form of recesses into which the end sections of the winding segments can be inserted such that they fit. 
         [0026]    A locking element is in the form of a recess allows simple passive locking of a winding segment or the end section of said winding segment with a small amount of freedom of movement. 
         [0027]    In some implementations, the apparatus includes a rotary drive device that is designed to rotate the holding device, the main bending device and/or the partial bending device in relation to one another about the axis. 
         [0028]    In some examples, the apparatus includes a linear drive device designed to move the holding device, the main bending device and/or the partial bending device independently of one another in the direction of the axis. 
         [0029]    Another aspect of the disclosure provides a method for bending a large number of winding segments for forming a winding of a winding support of an electrical machine. The method includes the following method steps: 
         [0030]    First, exposed end sections of first winding segments are locked. 
         [0031]    Then, the first winding segments are bent at respective bending regions in a first bending direction along a circumferential line. 
         [0032]    After this, the end sections of the first winding segments are further locked and bent at the respective bending regions in a second bending direction, which is opposite to the first bending direction, along the circumferential line. 
         [0033]    In some examples, after the first winding segments are bent in the first bending direction, exposed end sections of second winding segments are also locked in addition to the first winding segments. In the subsequent bending process, both the first and also the second winding segments may be bent at respective bending regions in the second bending direction along the circumferential line. 
         [0034]    Owing to the above-described method, the first and the second winding segments may be bent in a simple manner by the same ultimate bending angle but with different bending lengths. 
         [0035]    In some implementations, the first and the second winding segments are bent along an ellipsoidal, in particular a circular, circumferential line. 
         [0036]    The first and/or the second winding segments may be locked by inserting respective exposed end sections into respective recesses that firmly hold the corresponding end sections during the bending process. 
         [0037]    Yet another aspect of the disclosure provides a winding support, that is to say a rotor or a stator, for an electrical machine. The winding support includes a first group of winding segments for forming windings. The winding support further includes a second group of winding segments which, in addition to forming the windings, are further provided for interleaving the windings to form current phases and/or for establishing electrical connections from the windings or the current phases to an external current source. The current phases are, for example, the U, V, and W phases of a stator of an electrical machine. 
         [0038]    The winding segments of the first group each have a first, exposed bending region. The first bending region may be directly electrically connected to a bending region of another corresponding winding segment. Here, a “direct electrical connection” means an electrical connection, which is established without interposed winding segments. A connection of this kind is established, for example, by means of soldering or welding connection and possibly by means of an electrically conductive web that has been positioned between the two bending regions that are to be connected to one another. 
         [0039]    The winding segments of the second group may each have a second, exposed bending region. In some examples, the second bending region is directly electrically connected to an electrical line that leads to an external current source or is provided for interleaving the windings to form current phases. An electrical line is in the form of, for example, a busbar or a current cable. A “direct electrical connection” means an electrical connection that is established without interposed winding segments here too. A connection of this kind is established, for example, by means of soldering or welding connection and possibly by means of an electrically conductive web that has been positioned between the second bending region and the electrical line. In some implementations, the first bending region and the second bending region are bent by the same bending angle. In some examples, the winding support is produced in line with the above-described method. 
         [0040]    Another aspect of the disclosure provides an electrical machine having an above-described winding support, where the winding support is in the form of a stator or a rotor of the electrical machine. 
         [0041]    Advantageous refinements of the above-described apparatus, insofar as they can otherwise be transferred to the above-described method, to the above-described winding support or to the abovementioned electrical machine, can also be regarded as advantageous refinements of the method, of the winding support and, respectively, of the electrical machine. 
         [0042]    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 DRAWING 
         [0043]      FIG. 1  is a schematic view of an exemplary apparatus for bending winding segments. 
           [0044]      FIG. 2  is a schematic bottom view of main bending devices and partial bending devices of the exemplary apparatus of  FIG. 1 . 
           [0045]      FIG. 3  is a schematic view of an exemplary arrangement of operations of a method for bending winding segments. 
           [0046]      FIGS. 4A-4D  are schematic views of the exemplary apparatus of  FIG. 1  and intermediates of a winding support during production of the winding support in line with each method step according to the method illustrated in  FIG. 3 . 
       
    
    
       [0047]    Like reference symbols in the various drawings indicate like elements. 
       DETAILED DESCRIPTION 
       [0048]      FIG. 1  schematically shows an apparatus V for bending winding segments WS 1 , WS 2  of a winding support WT (see  FIGS. 4A-4D ), for example a stator, of an electrical machine, not illustrated in the figure. The apparatus V includes a holding device HE designed to firmly hold a winding support WT together with winding segments WS 1 , WS 2  arranged in the winding support WT. 
         [0049]    In some examples, the apparatus V further includes a first main bending device HB 1 , a first partial bending device PB 1 , a second main bending device HB 2  and a second partial bending device PB 2 . The first and the second main bending devices HB 1 , HB 2  are designed such that they may be bidirectionally rotated in relation to the holding device HE and about a rotation axis AS (see  FIG. 2 ), as illustrated in  FIG. 1  by a double-headed arrow DP. 
         [0050]    The first and the second partial bending devices PB 1 , PB 2  may be designed such that they can be unidirectionally rotated in relation to the holding device HE and about the rotation axis AS, as illustrated in  FIG. 1  by a single-headed arrow EP. Therefore, the two main bending devices HB 1 , HB 2  are also designed such that they can be bidirectionally rotated in relation to the two partial bending devices PB 1 , PB 2 . Similarly, the two partial bending devices PB 1 , PB 2  are designed such that they can be unidirectionally rotated in relation to the two main bending devices HB 1 , HB 2 . 
         [0051]    In addition, in some implementations, the main bending devices HB 1 , HB 2  and the partial bending devices PB 1 , PB 2  are designed such that they can be moved independently of one another and in relation to the holding device HE in the direction of the rotation axis AS. 
         [0052]    The apparatus V may additionally include a rotary drive device DA designed to rotate the two main bending devices HB 1 , HB 2  and also the two partial bending devices PB 1 , PB 2  independently of one another about the rotation axis AS and therefore bidirectionally and, respectively, unidirectionally in relation to the holding device HE. 
         [0053]    In some examples, the apparatus V includes a first transmission device GE 1  that mechanically connects the rotary drive device DA selectively to one or more of the two main and of the two partial bending devices HB 1 , HB 2 , PB 1 , PB 2  for transmitting kinetic energy. 
         [0054]    During operation of the apparatus V, the rotary drive device DA generates kinetic energy by means of first drive actuators, not illustrated in the figure. The kinetic energy is transmitted to the respective main and partial bending devices HB 1 , HB 2 , PB 1 , PB 2  by means of the first transmission device GE 1  and prompting the respective main and partial bending devices HB 1 , HB 2 , PB 1 , PB 2  to rotate in a bidirectional and, respectively, unidirectional manner. 
         [0055]    In some implementations, the apparatus V includes a linear drive device LA designed to move the two main bending devices HB 1 , HB 2  and the two partial bending devices PB 1 , PB 2  independently of one another in the direction of the rotation axis AS and therefore in relation to the holding device HE. 
         [0056]    The apparatus V may include a second transmission device GE 2  that mechanically connects the linear drive device LA selectively to one or more of the two main and of the two partial bending devices HB 1 , HB 2 , PB 1 , PB 2  for transmitting kinetic energy. 
         [0057]    During operation of the apparatus V, the linear drive device LA generates kinetic energy by means of second drive actuators, not illustrated in the figure. The kinetic energy is transmitted to the respective main and partial bending devices HB 1 , HB 2 , PB 1 , PB 2  by means of the second transmission device GE 2  and prompting the respective main and partial bending devices HB 1 , HB 2 , PB 1 , PB 2  to move axially in the direction of the rotation axis AS. 
         [0058]    The apparatus V may further include a control device SE that is electrically connected at the output end to the rotary drive device DA via a first signal line SL 1  and to the linear drive device LA via a second signal line SL 2 . 
         [0059]    In some implementations, during operation of the apparatus V, the control device SE sends a control signal to the rotary drive device DA via the first signal line SL 1  and prompts and rotary drive device DA to rotate the respective main and partial bending devices HB 1 , HB 2 , PB 1 , PB 2 . During operation of the apparatus V, the control device SE may send a control signal to the linear drive device LA via the second signal line SL 2  and prompts the linear drive device LA to move the respective main and partial bending devices HB 1 , HB 2 , PB 1 , PB 2  axially. 
         [0060]    Since the apparatus V has been roughly described with reference to  FIG. 1 , the two main bending devices HB 1 , HB 2  and the two partial bending devices PB 1 , PB 2  will be described in further detail below with reference to  FIG. 2 .  FIG. 2  shows a bottom view of the main and partial bending devices HB 1 , HB 2 , PB 1 , PB 2 . 
         [0061]    The first main bending device HB 1  includes three main bending sections HS 1 . 
         [0062]    The three main bending sections HS 1  are composed of, for example, a metal or a metal alloy. Here, the main bending sections HS 1  form three sections of a first “virtual” hollow cylinder and are arranged along three first sections AB 11  of a first circular “virtual” circumferential line UL 1  as viewed in the direction of the rotation axis AS. In some examples, the first main bending sections HS 1  are connected to one another by means of connecting elements, not illustrated in the figure. For example, the first main bending sections can be bidirectionally rotated in relation to one another synchronously about the rotation axis AS in a manner driven by the rotary drive device DA and can be moved in a linear manner in relation to one another synchronously in the direction of the rotation axis AS in a manner driven by the linear drive device LA. 
         [0063]    The first partial bending device PB 1  includes three partial bending sections PS 1  that are composed of, for example, a metal or a metal alloy. Here, the partial bending sections PS 1  form three sections of a first hollow cylinder and are arranged along three second sections AB 12  of the first circumferential line UL 1  as viewed in the direction of the rotation axis AS. In some examples, the first partial bending sections PS 1  are likewise connected to one another by means of connecting elements, not illustrated in the figure. For example, the first partial bending sections can be unidirectionally rotated in relation to one another synchronously about the rotation axis AS in a manner driven by the rotary drive device DA and can be moved in a linear manner in relation to one another synchronously in the direction of the rotation axis AS in a manner driven by the linear drive device LA. 
         [0064]    In some implementations, the three main bending sections HS 1  and the three partial bending sections PS 1  are arranged alternately in relation to one another in the direction of the first circumferential line UL 1 . 
         [0065]    In some examples, the number of main and partial bending sections HS 1 , PS 1  is determined by the number of current phases of the winding support WT, or of the stator, this number generally being three. In general, in each case one winding is provided for each of the three current phases. In order to form each individual winding, a main and a partial bending section HS 1 , PS 1  are needed in each case. When there are three current phases and therefore three windings, there are therefore three main and partial bending sections HS 1 , PS 1 . If two or more windings are provided for each of the three current phases, six or 3*n (that is to say a multiple of three) main and partial bending sections HS 1 , PS 1  are needed. This also applies in a similar way for main and partial bending sections HS 2 , PS 2  which will be described below. 
         [0066]    The first main bending device HB 1  may include a large number of main locking elements HA 1  that are in the form of recesses formed on respective surfaces OF 11  of the main bending sections HS 1 . The respective surfaces OF 11  face the holding device HE. For example, three of the main locking elements HA 1  are illustrated in Figure. In some examples, the main locking elements HA 1  are arranged at a distance from one another along the first circumferential line UL 1  and in accordance with the lateral distances between the pole slots of a winding support WT which will be described below. Furthermore, the main locking elements HA 1  may be designed in such a way that end sections EA 1  of first winding segments WS 1 , which will be described below, can be inserted into the respective corresponding main locking elements HA 1  such that they fit and can be firmly held by the respective main locking elements HA 1 . 
         [0067]    Similarly, in some examples, the first partial bending device PB 1  includes a large number of partial locking elements PA 1  which are likewise in the form of recesses that are formed on respective surfaces OF 12  of the partial bending sections PS 1 . The respective surfaces OF 12  face the holding device HE. For example,  FIG. 2  illustrates three of the partial locking elements PA 1 . As shown, the partial locking elements PA 1  are arranged at a distance from one another along the first circumferential line UL 1  and in accordance with the lateral distances between the pole slots of the winding support WT. Furthermore, the partial locking elements PA 1  may be designed in such a way that end sections EA 2  of second winding segments WS 2 , which are to be described below, can be inserted into the respective corresponding partial locking elements PA 1  such that they fit and can be firmly held by the respective partial locking elements PA 1 . 
         [0068]    The second main bending device HB 2  may likewise include three main bending sections HS 2  which are composed of, for example, a metal or a metal alloy. Here, the main bending sections HS 2  form three sections of a second “virtual” hollow cylinder, which is coaxial with the first hollow cylinder, and are arranged along three first sections AB 21  of a second circular “virtual” circumferential line UL 2  as viewed in the direction of the rotation axis AS. These main bending sections HS 2  are connected to one another by means of connecting elements, not illustrated in the figure, such that the main bending sections may be bidirectionally rotated in relation to one another synchronously about the rotation axis AS in a manner driven by the rotary drive device DA and can be moved in a linear manner in relation to one another synchronously in the direction of the rotation axis AS in a manner driven by the linear drive device LA. 
         [0069]    The second partial bending device PB 2  may likewise include three partial bending sections PS 2  which are composed of, for example, a metal or a metal alloy. Here, the partial bending sections PS 2  form three sections of the second hollow cylinder and are arranged along three second sections AB 22  of the second circumferential line UL 2  as viewed in the direction of the rotation axis AS. These partial bending sections PS 2  are likewise connected to one another by means of connecting elements, not illustrated in the figure, such that said partial bending sections may be unidirectionally rotated in relation to one another synchronously about the rotation axis AS in a manner driven by the rotary drive device DA and may be moved in a linear manner in relation to one another synchronously in the direction of the rotation axis AS in a manner driven by the linear drive device LA. 
         [0070]    In some examples, as shown, the three main bending sections HS 2  and the three partial bending sections PS 2  are arranged alternately in relation to one another in the direction of the second circumferential line UL 2 . 
         [0071]    The second main bending device HB 2  includes a large number of main locking elements HA 2  that are in the form of recesses that are formed on respective surfaces OF 21 , which face the holding device HE, of the main bending sections HS 2  (three of the main locking elements HA 2  are illustrated in  FIG. 2  by way of example). In some examples, the main locking elements HA 2  may be arranged at a distance from one another along the second circumferential line UL 2  and in accordance with the lateral distances between the pole slots of the winding support WT. Furthermore, the main locking elements HA 2  may be designed in such a way that end sections of winding segments, which are to be described below, may be inserted into the respective corresponding main locking elements HA 2  such that they fit and can be firmly held by the respective main locking elements HA 2 . 
         [0072]    Similarly, the second partial bending device PB 2  may include a large number of partial locking elements PA 2  which are likewise in the form of recesses which are formed on respective surfaces OF 22 , which face the holding device HE, of the partial bending sections PS 2  (three of the partial locking elements PA 2  are illustrated in  FIG. 2  by way of example). Here, the partial locking elements PA 2  are arranged at a distance from one another along the second circumferential line UL 2  and in accordance with the lateral distances between the pole slots of the winding support WT. Furthermore, the partial locking elements PA 2  are designed in such a way that end sections of winding segments, which are to be described below, can be inserted into the respective corresponding partial locking elements PA 2  such that they fit and can be firmly held by the respective partial locking elements PA 2 . 
         [0073]    Since the apparatus V for bending winding segments WS 1 , WS 2  has been described in detail with reference to  FIGS. 1 and 2 , a corresponding method for bending winding segments WS 1 , WS 2  will be described in greater detail below with reference to  FIGS. 3 and 4A to 4D .  FIG. 3  shows the sequence of the method using a schematic flowchart.  FIGS. 4A to 4D  are each schematic illustrations of sections of the main bending device HB 1  and of the partial bending device PB 1  of the apparatus V and three of the first and three of the second winding segments WS 1 , WS 2  before, during and after respective method steps of said method. 
         [0074]    In order to produce windings of the winding support WT, a large number of winding pins are inserted into corresponding pole slots, which are provided for them, of a hollow-cylindrical laminated core. The winding pins are of hairpin-shaped design and each have two bar-like limbs. The two limbs of the respective winding pins are interleaved and interlocked by a spreading step by means of a winding step of the winding support and inserted into the corresponding pole slots in accordance with the winding step of the winding support WT, wherein a region of the respective winding segments, together with an exposed end section, protrudes out of the laminated core in each case. These limbs serve for forming windings and are therefore called winding segments in the text which follows. 
         [0075]    As an alternative to the winding pins which are in the shape of hairpins, bar or I-like winding bars may also be used for forming windings, the winding bars then serving as winding segments for forming windings. 
         [0076]    As viewed from the cylinder axis of the laminated core in the radial direction, a winding segment of a winding pin and a winding segment of a further winding pin are therefore arranged radially one behind the other in each of the pole slots. Here, the two winding segments are electrically insulated from one another and from the laminated core by an insulation means, such as an insulating paper for example. 
         [0077]    Those winding segments of the respective two winding segments in the respective pole slots which are situated at a further distance from the cylinder axis lie on a first “virtual” circle around the cylinder axis as viewed in the direction of the cylinder axis, wherein the first circle and the abovementioned first circumferential line UL 1  have the same shape. These winding segments are called outer winding segments WS 1 , WS 2  in the text which follows. 
         [0078]    A first group of outer winding segments, which form a large number of the outer winding segments and serve exclusively for forming windings, are called first winding segments WS 1  in the text which follows. A second group of outer winding segments, which form a small number of the outer winding segments and, in addition to forming windings, further serve for establishing electrical connections to external current lines, are called second winding segments WS 2  in the text which follows. 
         [0079]    In some examples, those winding segments of the respective two winding segments in the respective pole slots which are situated at a closer to the cylinder axis lie on a second “virtual” circle, which is concentric in relation to the first circle, around the cylinder axis as viewed in the direction of the cylinder axis, wherein the second circle and the abovementioned second circumferential line UL 2  have the same shape. These winding segments are called inner winding segments in the text which follows. 
         [0080]    A first group of inner winding segments, which form a large number of the inner winding segments and serve exclusively for forming windings, are called third winding segments in the text which follows. A second group of inner winding segments, which form a small number of the inner winding segments and, in addition to forming windings, further serve for establishing electrical connections to external current lines, are called fourth winding segments in the text which follows. 
         [0081]    After the winding segments are inserted into the corresponding pole slots, the respective regions which protrude out of the laminated core form respective bending regions of the winding segments together with the respective exposed end sections. 
         [0082]    In order to form windings, the bending regions BB 1 , BB 2  of the outer winding segments WS 1 , WS 2  are bent along the first circumferential line UL 1 , which corresponds to the first “virtual” circle, in a bending direction BR 2  in a manner which will be described below. Accordingly, the bending regions of the inner winding segments are bent in a similar way to the bending regions BB 1 , BB 2  of the outer winding segments WS 1 , WS 2  along the second circumferential line UL 2 , which corresponds to the second “virtual” circle, in a bending direction which is opposite to the bending direction of the outer winding segments WS 1 , WS 2 . 
         [0083]    To this end, the winding support WT, together with the winding segments WS 1 , WS 2 , is initially held in a stationary manner by the holding device HE concentrically in relation to the holding device HE. 
         [0084]    The first exposed end sections EA 1  of the first winding segments WS 1  are then locked in line with method step S 100 . To this end, the control device SE outputs a first control signal to the linear drive device LA and prompts said linear drive device to move the main bending device HB 1  axially in relation to the holding device HE in direction SR. Owing to the axial movement of the main bending device HB 1 , the first main locking elements HA 1 , which are in the form of recesses, are lowered onto the end sections EA 1 . In the process, the main bending device HB 1  receives the corresponding end sections EA 1  and firmly holds said end sections (compare with  FIG. 4A ). 
         [0085]    While the end sections EA 1  are firmly held by the main locking elements HA 1 , the first winding segments WS 1  are bent at the respective bending regions BB 1  in a first bending direction BR 1  along the circumferential line UL 1  in line with a further method step S 200 . To this end, the control device SE outputs a second control signal to the rotary drive device DA and prompts said rotary drive device to rotate the main bending device HB 1  about the rotation axis AS in relation to the holding device HE. Owing to the rotary movement of the main bending device HB 1 , the winding segments WS 1  are bent at the respective bending regions BB 1  (compare with  FIG. 4B ). 
         [0086]    The end sections EA 2  of the second winding segments WS 2  are then locked in line with a further method step S 300 , while the end sections EA 1  of the first winding segments WS 1  continue to be firmly held. To this end, the control device SE outputs a third control signal to the linear drive device LA and prompts said linear drive device to move the partial bending device PB 1  axially in relation to the holding device HE in direction SR. Owing to the axial movement of the partial bending device PB 1 , the first partial locking elements PA 1 , which are likewise in the form of recesses, are lowered onto the end sections EA 2  of the second winding segments WS 2 . In the process, the partial locking elements PA 1  receive the corresponding end sections EA 2  of the second winding segments WS 2  and firmly hold said end sections (compare with  FIG. 4C ). 
         [0087]    While the end sections EA 1 , EA 2  are firmly held by the respective corresponding main and partial locking elements HA 1 , PA 1 , the first and the second winding segments WS 1 , WS 2  are bent at the respective bending regions BB 1 , BB 2  in a second bending direction BR 2 , which is opposite to the first bending direction BR 1 , along the circumferential line UL 1  in line with a further method step S 400 . To this end, the control device SE outputs a fourth control signal to the rotary drive device DA and prompts said rotary drive device to rotate the main and partial bending device HB 1 , PB 1  about the rotation axis AS in relation to the holding device HE. Owing to the rotary movement of the main and partial bending device HB 1 , PB 1 , the winding segments WS 1 , WS 2  are bent at the respective bending regions BB 1  (compare with  FIG. 4D ). 
         [0088]    Owing to the bending of the first winding segments WS 1  in the first bending direction BR 1  and owing to the subsequent further bending of the first and the second winding segments WS 1 , WS 2  in the opposite bending direction BR 2 , the first and the second winding segments WS 1 , WS 2  are bent with different bending lengths BL 1 , BL 2  but by the same ultimate bending angle BW (compare  FIG. 4D ). As a result, the winding segments WS 1 , WS 2  may be bent further than winding segments which are all bent only in one bending direction in a single bending process. The winding support WT with winding segments WS 1 , WS 2  which are bent further in such a way therefore has a winding head with a low winding head height. 
         [0089]    In some examples, the inner winding segments are likewise bent with different bending lengths but by the same ultimate bending angle. 
         [0090]    In some implementations, a first group of inner winding segments, which, like the first outer winding segments WS 1 , serve exclusively for forming windings, are firmly held by the main locking elements HA 2  of the second main bending device HB 2  in line with method step S 100  and bent at the respective bending regions in line with method step S 200 . In the process, the first inner winding segments are bent in a bending direction that is opposite to the first bending direction BR 1  of the first outer winding segments WS 1 . A second group of inner winding segments, which, like the second outer winding segments WS 2 , in addition to forming windings, may further serve for establishing electrical connections to the external current lines, is firmly held by the partial locking elements PA 2  of the second partial bending device PB 2  in line with method step S 300 . Subsequently, the first and the second inner winding segments are bent in a bending direction that is opposite to the second bending direction BR 2  of the outer winding segments WS 1 , WS 2 , in line with method step S 400 . 
         [0091]    After the bending process, the end sections EA 1  of the first outer winding segments WS 1  are electrically connected to the end sections of the respective first inner winding segments, which are arranged at a distance from the respective first outer winding segments WS 1  in line with the winding step, by soldering or welding connection. The end sections EA 2  of the second outer winding segments WS 2  and the end sections of the second inner winding segments are electrically connected to the external current lines by soldering or welding connection. 
         [0092]    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.