Abstract:
The invention relates to an electric machine ( 10 ), in particular a generator for a motor vehicle, comprising an exciter system composed of a plurality of electrically excited salient poles. The salient poles can be designed within the stator ( 16 ) or rotor ( 20 ) in the form of electromagnetically excited poles ( 22, 23; 24, 25 ) which are axially and radially oriented on the periphery and are alternatively polarized in the peripheral direction. In order to improve performance and reduce the magnetic leakage flux, permanent magnets ( 66 ), which are secured by means of a magnetically non-excitable holding element ( 60 ), are inserted into interstices ( 74 ) between the alternating poles ( 24, 25 ). The holding element ( 60 ) is bilaterally mounted in pole grooves ( 92, 94 ), is radially, axially, and tangentially resilient, and has a wave-shaped ( 62 ) and/or bead-shaped ( 76, 78; 86 ) profile.

Description:
BACKGROUND OF THE INVENTION 
       [0001]    The German patent publication DE 10 2006 041 981 A1 relates to an electric machine. The electric machine relates particularly to an electrically excited claw-pole generator for a motor vehicle. The claw-pole generator comprises a rotor having a plurality of axially oriented poles which alternate magnetization in the peripheral direction and permanent magnets disposed between the poles for increasing performance and reducing the magnetic leakage flux. The permanent magnets are secured by means of non-magnetic plates bilaterally held in pole grooves. These plates comprise in each case at least one additional locking mechanism with which they are supported in the axial direction at the poles. The additional locking mechanisms are, for example, designed as sheet metal tabs which are bent or angled and are supported in a resiliently clamping manner at least one axial end section of the poles. 
         [0002]    The German patent publication DE 199 51 115 A1 likewise relates to an electric machine. This electric machine relates to a generator for a motor vehicle having an exciter system and a plurality of electrically excited salient poles in the stator or rotor. The stator as well as the rotor thereby comprises the form of electromagnetically excited poles which are axially oriented on the periphery and are alternatively polarized in the peripheral direction. In order to reduce magnetic leakage flux, permanent magnets are situated in the interstices between the poles. The permanent magnets are inserted into the aforementioned interstices. Said permanent magnets on the stator, respectively the rotor, are secured in such a way that they are in each case held by means of a magnetically non-excitable holding element. This holding element is bilaterally mounted in pole grooves in the tangential and axial directions by means of caulking; and a pole groove is longitudinally incorporated into one pole and a pole groove is longitudinally incorporated into an opposite pole. In the case of a rotor, the holding element covers the respective permanent magnet in the radial direction to the stator or in the case of a stator in the radial direction to the rotor with a base section. Bent tabs, which exert a clamping force on axial front faces of the inserted permanent magnets, are located at each of the opposite ends of the base section. 
         [0003]    In the case of electric machines as those known from the German patent publications DE 19 2006 041 981 A1 and DE 199 51 115 A1, the claw poles of a claw-pole machine tend to bend up radially outwards at high rotational speeds &gt;20,000 rpm. This deformation occurs more or less dramatically, in each case depending on the rotational speed of the electric machine. 
       SUMMARY OF THE INVENTION 
       [0004]    In order to lock the permanent magnets in place, resiliently embodied holding elements in the form of corrugated sheet are introduced in guide grooves on the sides of the claws. Said holding elements are capable of compensating very well for the installation tolerances and are able themselves to find the groove, in which said resiliently embodied holding elements are to be mounted, by means of an insertion tongue centrally positioned in relation to the interstice. This substantially eases assembly. An embodiment option, wherein the grooves are configured to run continuously in the axial direction, permits the permanent magnets having a resiliently embodied holding element to be inserted into the already completely assembled rotor. If the grooves are not manufactured to run continuously, bilateral, axial stops are then defined on the claw-pole flanks. In this case, a paired construction having a small connecting plate around the claw tip of a claw pole can occur. 
         [0005]    The magnets are fixed axially by means of the holding elements, which are resiliently embodied in the form of corrugated sheet, and fixed and positioned in the radial direction. The resiliently embodied holding elements relate preferably to those which have a pattern in the form of corrugated sheet and have lateral corrugations. Despite the thin wall thickness, this embodiment provides a very good rigidity against bending as protection for the magnets against the very high centrifugal forces occurring at high speed. Due to said thin wall thickness manufactured into the holding elements resiliently embodied in the form of corrugated sheet, the dead load is very slight. The spring properties, i.e. the elasticity of the resiliently embodied holding element, allows for an exact positioning and fixing thereof. The resiliently embodied holding element correspondingly formed from non-electromagnetic spring material prevents electromagnetic short circuits. The electric machine proposed according to the invention has substantially reduced losses in performance due to smaller air gaps and a large two-dimensional overlapping between magnets and claw flanks. The durability of the electric machine against mechanical, electrical and thermal stresses is considerably increased. As a result of the definable positioning, relative small mechanical and electromagnetic imbalances occur and thereby reduced noise emissions ensue on account of a high degree of accuracy in the axial, radial and tangential positioning of the permanent magnets. The solution proposed according to the invention opens the possibility of magnetizing said magnets after assembly. 
         [0006]    Due to the design of the holding element resiliently embodied in the form of corrugated sheet and the manufacture thereof from non-electromagnetic material, a resilient axial and radial positioning and fixing of the permanent magnets is achieved by the resilient holding elements laterally formed in the manner of a corrugated sheet in the preassembled as well as assembled state. An increase in performance, respectively a minimization of the losses can be achieved by large, lateral, easily accessible magnetic surfaces, which substantially abut against the sides of the claws. 
         [0007]    In a first embodiment option, the holding elements proposed according to the invention, which are substantially configured in the form of corrugated sheet and resiliently embodied, can be used for block-shaped magnets without interior front faces of the claws. These magnets have linear supports in the radial direction. This design leads to a good distribution of the centrifugal force load and places reduced rigidity demands on the resiliently embodied holding elements. The number and configuration of the corrugations can be easily varied depending on the length of the magnet. 
         [0008]    In a second embodiment, the holding plates comprise longitudinally formed, respectively indented or impressed, surfaces, which provide a support plane for the magnets against the risk of breakage at high centrifugal force loads. 
         [0009]    Obliquely chamfered surfaces of the magnets, which substantially correspond to the claw contours, provide additional advantages with regard to material savings as well as to a reduction in the centrifugal forces which occur. The possible modifications result from the fact that resiliently embodied holding elements can be configured in V-form for two magnet assemblies or alternatively as a continuously embodied annulus with all of the magnets. 
         [0010]    Integrally formed parallel longitudinal grooves, respectively longitudinal beads, provide a very good rigidity, respectively high bending moment of inertia, against bending as a protection of the magnets against the very high centrifugal forces which occur. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0011]    The invention is explained below in more detail with the aid of the drawings. 
           [0012]    The following are shown; 
           [0013]      FIG. 1  a sectional view through an electric machine, in particular a generator, 
           [0014]      FIG. 2  a frontal view of the claw pairing of the rotor, respectively the armature, 
           [0015]      FIG. 3  a top view, respectively side view, of the claw-shaped pole arrangement, 
           [0016]      FIG. 4  a detailed view of the permanent magnets which are fixedly secured by resiliently embodied holding elements, 
           [0017]      FIG. 5  a view of the permanent magnets with the holder, 
           [0018]      FIG. 6  a wave-shaped structure of the resiliently embodied holding elements, 
           [0019]      FIG. 7  the block-shaped permanent magnet as well as the resiliently embodied holding element engaging over said magnet, 
           [0020]      FIG. 8  a perspective depiction of the top view according to  FIG. 3  in an enlarged scale, 
           [0021]      FIG. 9  a further embodiment option of the permanent magnets, for example, resiliently embodied holding elements for fixation, 
           [0022]      FIG. 10  a view from below, 
           [0023]      FIG. 11  an enlarged perspective top view of the resiliently embodied holding element according to the embodiment option in  FIG. 9 , 
           [0024]      FIG. 12  a side view of the arrangement depicted in  FIG. 11 , 
           [0025]      FIG. 13  a side view only of the resiliently embodied holing element according to the embodiment option in  FIG. 9 , 
           [0026]      FIG. 14  a top view of the resiliently embodied holding element, 
           [0027]      FIG. 15  a view of the laterally bent sections of the same, 
           [0028]      FIG. 16  a claw half shell of the electric machine having the embodiment option for radial installation, 
           [0029]      FIG. 17  a top view of a further embodiment of the double resiliently embodied holding elements for fixing the permanent magnets, 
           [0030]      FIG. 18  side view and top view of the embodiment option of the resiliently embodied holding elements according to  FIG. 17  and 
           [0031]      FIG. 19  a top view of a resiliently embodied holding element provided with longitudinal beads, 
           [0032]      FIGS. 20  A and B a spatial view of a partial section of a further exemplary embodiment of a holding element, 
           [0033]      FIGS. 21  A and  21  B two views of a further exemplary embodiment of a holding element, 
           [0034]      FIGS. 22  A and  22  B two views of a further exemplary embodiment of a holding element, 
           [0035]      FIG. 23  a spatial view of a further exemplary embodiment of a holding element. 
       
    
    
     DETAILED DESCRIPTION 
       [0036]    In  FIG. 1  a cross-section through an electric machine  10  can be seen, embodied here as a generator, respectively alternator, for motor vehicles. This electric machine  10  includes among other things a two-parted housing  13 , which comprises a first end shield  13 . 1  as well as a second end shield  13 . 2 . The first end shield  13 . 1  and the second end shield  13 . 2  contain a stator  16 , which on the one hand consists substantially of a circularly annular stator iron core  17  and a stator winding  18  is inserted, respectively fed, into the grooves thereof which are directed radially inwards and extend axially. The annular stator  16  encloses a rotor  20 , which is embodied as a claw-pole armature, with the grooved surface thereof which is directed radially inwards. The rotor  20  comprises among other things two claw-pole plates  22  and  23 , on whose outside periphery claw-pole fingers  24 ,  25  are arranged, which extend in the axial direction or are configured to be bent. Both claw-pole plates  22  and  23  are disposed in the rotor  20  in such a way that the claw-pole fingers  24  and  25  thereof, which extend in the axial direction, alternate with one another about the periphery of said rotor  20 . As a result, magnetic, essential interstices or separating spaces between the mutually magnetized claw-pole fingers  24  and  25  arise, which are denoted as claw-pole interstices. Said rotor  20  is supported by means of a shaft  27  and in each case a roller bearing  28  situated on each side of said rotor  20  in the respective end shields  13 . 1  and  13 . 2 . 
         [0037]    The rotor  20  comprises altogether two axial front faces, to which in each case a fan is attached. This fan  30  consists substantially of a wave plate-shaped or disk-shaped section, from which fan blades emanate in a known way. These fans  30  serve to facilitate an air exchange between the exterior of the electric machine  10  and the interior of said electric machine  10  via openings  40  in the end shields  13 . 1  and  13 . 2 . For this purpose, the openings  40  are provided substantially on the axial ends of the end shields  13 . 1  and  13 . 2 . Cool air is drawn by said fans  30  into the interior of said electric machine  10  via said openings  40 . This cool air is accelerated radially outwards by the rotation of said fans  30 ; thus enabling said cool air to flood through the winding overhang  45 . Said winding overhang  45  is cooled by means of this effect. After flooding through said winding overhang  45  or as the case may be flowing around said winding overhang  45 , the cool air takes a course radially outwards through openings not depicted here in  FIG. 1 . 
         [0038]    A protective cap  47  is situated on the right side, which protects various components from environmental influences. This protective cap  47  covers, for example, a slip ring assembly  49 , which serves the purpose of supplying an excitation winding  51  with an exciting current. A cooling body  53  is arranged around this slip ring assembly  49 , which in this case acts as a plus cooling body. The end shield  13 . 2  acts as a so-called minus cooling body. A connecting plate  56  is located between said end shield  13 . 2  and the cooling body  53  and is used to connect the minus diode  58  disposed in said end shield  13 . 2  to plus diodes, which are not shown here in this depiction, in said cooling body  53  and thus to form a bridge circuit. 
         [0039]    A top view of a rotor block of the electric machine  10  can be seen in the depiction pursuant to  FIG. 2 . 
         [0040]    In the depiction pursuant to  FIG. 2 , the claw-pole plate  22  of the rotor  20  is illustrated, from which the claw-pole fingers denoted with the reference numeral  24  extend into the drawing plane. Interstices  74 , in which permanent magnets  66  are disposed and which can be seen in  FIG. 3 , are situated between the individual and conically configured claw-pole fingers  24 . The permanent magnets  66  ( FIG. 4 ) are used for the reduction of the magnetic leakage flux. Said permanent magnets  66  are affixed in the interstices  74  between the individual claw-pole fingers  24  and  25  of the electric machine  10  by means of holding elements  60 , which are resiliently embodied according to the invention. For this purpose, the resiliently embodied holding elements  60  proposed according to the invention are inserted into pole grooves  92 ,  94  which face each other, as indicated in the frontal view in  FIG. 2 . The pole grooves  92  and  94  are substantially configured as slots and extend in the axial direction along the conically designed pole finger flanks into the drawing plane pursuant to the depiction in  FIG. 2 . 
         [0041]    The top view according to  FIG. 3  shows that the rotor  20  of the electric machine  10  depicted there comprises two claw-pole plates  22 , respectively  23 , which are inserted into one another. Starting from the front faces of the claw-pole plates  22 ,  23 , the individual claw-pole fingers denoted by the reference numerals  24 ,  25  extend in an alternating sequence. The interstices  74  extend between the claw-pole fingers  24 ,  25  pursuant to the depiction in  FIG. 3 . Said interstices  74  are bounded by pole grooves  92 ,  94  which face each other and are embodied in an alternating sequence in the sides of the claw poles fingers  24 , respectively  25 . 
         [0042]    It can be seen in the depiction pursuant to  FIG. 3  that holding elements  60  resiliently embodied according to the invention are inserted into the pole grooves  92 ,  94  between the individual claw-pole fingers  24 ,  25 . The resiliently embodied holding elements  60  include in each case clamping brackets  64  of curved design, which in the top view pursuant to  FIG. 3  affix the permanent magnet  66  covered by the resiliently embodied holding element  60 . Due to the limitations of the drawn, visible representation, the permanent magnet  66  for reducing the magnetic leakage flux, which is affixed by each resiliently embodied holding element  60 , is not depicted. 
         [0043]    It can be seen in  FIG. 3  that the individual, resiliently embodied holding elements  60  have a wave-shaped profile  62 . The number and form of the waves are dependent upon the required length of the magnet, the required clamping force and the rotational speed of the electric machine. The wave-shaped profile  62  extends in the axial direction of the resiliently embodied holding element  60  from a clamping bracket  64  up to the opposite resiliently embodied clamping bracket  64 . By means of the resiliently embodied clamping brackets  64 , the permanent magnets  66  are fixed on the respective front faces thereof and fit snugly with at least one longitudinal side against the bottom side of said resiliently embodied holding element  60 . 
         [0044]    It is indicated in the depiction pursuant to  FIG. 3  that the resiliently embodied holding elements  60  have been inserted into the pole grooves  92 ,  94 . For that reason, said resiliently embodied holding elements  60  are configured wider with regard to the width thereof in relation to the width of the clamping brackets  64 ; thus enabling the edge areas of the resiliently embodied holding elements  60 , which run laterally, to project into the respective pole grooves  92 ,  94  and a reliable mechanical fixing of the permanent magnets  66  to be facilitated even at high and the highest rotational speeds of the electric machine  10 . 
         [0045]      FIG. 4  shows a perspective view of the permanent magnets  66  affixed by the resiliently embodied holding elements  60 . 
         [0046]    It can be seen in the depiction pursuant to  FIG. 4  that the resiliently embodied holding elements  60  fix the permanent magnets  66  at the front faces  70  thereof by means of the clamping brackets  64 . Due to the widened configuration of the resiliently embodied holding element  60 , the edge regions thereof are inserted into the pole grooves  92 ,  94  depicted in  FIG. 4 , which are configured in the individual claw-pole fingers  24 , respectively  25 , and reliably anchored there. During a rotation of the electric machine  10 , i.e. of the rotor  20 , said resiliently embodied holding elements  60  form a reliable, mechanical, loss-proof fixing of said permanent magnets  66 , which abut snugly against the bottom side  72  of said resiliently embodied holding elements  60  during a rotation of said rotor  20  of said electric machine  10 . 
         [0047]    It can be seen in  FIG. 5  that the permanent magnets  66  are configured block-shaped and that the resilient clamping brackets  64  clamp the opposing front faces  70  of a permanent magnet  66  to be fixed in place. The permanent magnet  66  rests, as can be seen in  FIG. 5 , with at least one of the longitudinal sides  68  thereof against the bottom side  72  of the resiliently embodied holding element  60 . As  FIG. 5  furthermore shows, the width of said resiliently embodied holding element  60  exceeds the width of said permanent magnet  66  to be fixed in place. The reason for this is that said resiliently embodied holding element  60  is inserted with the lateral edges of the wave-shaped  62  profile thereof into the pole grooves  92 ,  94  of the claw-pole fingers  24 ,  25 . Said wave-shaped  62  profile advantageously facilitates the reception of elastic deformations of said claw-pole fingers  24 ,  25  at high rotational speeds as well as a compensation of deformations, which occur as a result of centrifugal force load. In so doing, the mechanical load has been taken off said permanent magnets  66  fixed in place by said resiliently embodied holding elements  60  proposed by the invention. Deformations occurring due to thermally related stresses, even those occurring in said claw-pole fingers  24  or  25 , can also be easier absorbed on account of the profiled design of said resiliently embodied holding elements  60  proposed according to the invention. Furthermore, a smaller mechanical imbalance can be achieved by means of the design of said resiliently embodied holding elements  60  proposed according to the invention, whereby a reduction in the noise level can also be achieved. The pole grooves  92  or  94  on the sides of the claw-pole fingers  24 ,  25  in the region of the interstices  74  are preferably formed by a cutting operation, can however also be formed without cutting on account of the resilient fitting. 
         [0048]    Due to the fact that the clamping brackets  64  are configured on the resiliently embodied holding elements  60  so as to be centrally positioned in relation to the interstice  74 , said holding elements  60  are well able to find the pole grooves  92 ,  94  themselves. This substantially eases assembly. If axially continuous grooves are installed on the claw-pole fingers  92 ,  94 , the permanent magnets  66  mounted on the resiliently embodied holders  60  proposed according to the invention can be inserted into the completely assembled rotor  20 . In the case of non-continuously embodied pole grooves  92 ,  94 , bilateral, axial stops are defined by the flanks of the claw-pole fingers  24  or the two claw-pole plates  22 ,  23 . The lateral corrugations of the wave-shaped  62  profile, which run parallel to one another and are formed in said holding elements  60 , provide very good rigidity against bending as well as protection for the permanent magnet  66  positioned on the bottom side  72 . Due to the thin wall thickness, the dead load is very slight and the resilient embodiment enables said magnets  66  to be precisely fixed and positioned. The resiliently embodied holding element  60  is preferably manufactured from non-electromagnetic and stainless material and enables a resilient, axial and radial positioning of said permanent magnets  66  in the interstices  74 , whereby said permanent magnets  66  are to be secured and protected against centrifugal forces and corrosion. 
         [0049]    The depiction pursuant to  FIG. 6  reveals how the permanent magnet  66  is affixed on the front faces  70  thereof by means of the clamping brackets  64  engaging over said front faces  70 . Moreover, the wave-shaped profile is illustrated in the depiction pursuant to  FIG. 6 . 
         [0050]    It can be seen in the depiction pursuant to  FIG. 7  that the permanent magnet  66  can, for example, be configured block-shaped. The permanent magnets  66  can include linear supports which extend radially. This design provides good features for the distribution of the centrifugal force load, whereby the rigidity demands on the resiliently embodied holding element  60  can be reduced. 
         [0051]    The depiction pursuant to  FIG. 8  reveals how the resiliently embodied holding elements are inserted into the pole grooves  92 ,  94 . Said pole grooves  92 ,  94  lie on the mutually facing lateral edges of the claw-pole fingers  24  or  25 , which mutually face each other along the interstices  94 . 
         [0052]    It can be seen in the depiction pursuant to  FIG. 9  that the resiliently embodied holding elements  60  proposed according to the invention can include in a preferred embodiment of the same a longitudinal stiffener, as, for example, in the form of a longitudinal bead  76  in the region of their wave-shaped profile. Said depiction pursuant to  FIG. 9  further reveals that the longitudinal bead  76  can be introduced into the surface of the holding element  62  having in this case a wave-shaped profile, as, for example, by punching/stamping or impressing. Pursuant to the depiction in  FIG. 9 , said longitudinal bead  76  extends from the center of one of the clamping brackets  64  to the center of the other clamping bracket  64 . 
         [0053]      FIG. 10  shows that a stiffening bead base  78  extending in a planar manner results on the bottom side  72  of the resiliently embodied holding element  60  due to the stamping, respectively introducing, of the longitudinal bead  76  into the material thereof. Instead of the longitudinal bead  76  shown in the depictions pursuant to  FIGS. 9 and 10 , which is centrally introduced, respectively stamped, two adjacent or a plurality of longitudinal beads  76  extending in the longitudinal direction can also be designed into the resiliently embodied holding element  60  proposed according to the invention. 
         [0054]      FIG. 11  shows that the longitudinal bead  76  extends from one of the clamping brackets  64  to the other clamping bracket  64  and that the permanent magnet  66 , which in this instance is block-shaped, is fixed on the front faces thereof. Pursuant to the depiction in  FIG. 10 , said block-shaped permanent magnet  66  rests with one of the longitudinal sides  68  thereof against the bottom side of the planar stiffening bead base  78 . This can be very well seen in the side views of the resiliently embodied holding element  60  proposed according to the invention pursuant to  FIGS. 12 and 13 . 
         [0055]    The depiction pursuant to  FIG. 12  reveals that a longitudinal side  68  of the permanent magnet  66  fits snugly against the bottom side of the corrugated base  78  of the resiliently embodied holding element  60 . The permanent magnet  66  is enclosed on the mutually opposing front faces  70  by the resiliently embodied clamping brackets  64 . 
         [0056]      FIG. 13  shows that the clamping brackets  64  are bent at a bracket angle  80 , which in relation to the stiffening bead base  78 , i.e. the bottom side of the resiliently embodied holding element  60 , lies in the range between 0° and 60°, preferably between 15° and 45°. The sides of the wave-shaped profile can be open or closed, as, for example, cast with a filling material.  FIG. 13  shows that a stiffening bead base  78  extending in a planar manner results by virtue of introducing the longitudinal bead  76  into the wave-shaped  62  profile. Said stiffening bead base  78  constitutes a planar surface, against which at least one longitudinal side  68  of the permanent magnet  66  abuts snugly upon rotation of the rotor  20 . 
         [0057]    It can be seen in the top view pursuant to  FIG. 14  that the longitudinal bead  76  has been introduced into the wave-shaped  62  profile. Edge regions of said wave-shaped  62  profile are inserted into the correspondingly configured pole grooves  92 ,  94  of the claw-pole fingers  24 ,  25  and therefore locked in place there. The depiction pursuant to  FIG. 14  reveals that a width  84  of the resiliently embodied holding element  60  exceeds the width of the clamping bracket  64  (cf. depiction pursuant to  FIG. 15 ). The lateral regions of said wave-shaped  62  profile facilitate the locking in place of said resiliently embodied holding element  60  in said pole grooves  92 ,  94  of said claw-pole fingers  24 ,  25 . 
         [0058]      FIG. 15  shows that a clamping bracket width  82  of the clamping brackets  64  is approximately twice the size of the width  84  (cf. depiction pursuant to  FIG. 14 ) of the resiliently embodied holding element  60 . The clamping bracket width  82  is calculated such that it almost completely covers the front faces  70  of the permanent magnet  66  when the resiliently embodied holding element  60  is mounted in the pole grooves  92 ,  94 . In so doing, a reliable fixing of said permanent magnet  66  in the interstices  74  between the claw-pole fingers  24 ,  25  is ensured even when high peripheral speed and high centrifugal forces occur. 
         [0059]      FIG. 16  shows a further embodiment option of the resiliently embodied holding element  60  proposed according to the invention. Provision is particularly made for this option in the case of radial mounting from above or from outside inwards of the finished rotor assemblies. 
         [0060]    The depiction pursuant to  FIG. 16  reveals that the claw-pole plate  22  comprises a number of claw-pole fingers  24 , wherein corresponding clearances, in which the claw-pole fingers  24  of another claw-pole plate engage, are configured between said claw-pole fingers  24 . For reasons of clarity, only one of the claw-pole plates  22 ,  23  is depicted in the perspective view pursuant to  FIG. 16 . In the depiction pursuant to  FIG. 16 , the permanent magnets  66  are likewise fixedly secured by resiliently embodied holding elements  60 , which however in comparison to the first embodiment option of the resiliently embodied holding elements  60  depicted in  FIG. 9  comprise a longitudinal ribbing  86  to prevent the magnets from buckling. It can be seen in  FIG. 16  that the longitudinal ribbing  86  of the two recesses extending parallel to one another, i.e. the longitudinal beads  76 , is depicted in the surface of said resiliently depicted holding elements  60  which covers said permanent magnets  66 . Clamping projections  90 , which engage in the pole grooves  92 ,  94  of said claw-pole fingers  24 ,  25  of said claw-pole plates, extend on both sides of said longitudinal ribbing  86 . 
         [0061]    In contrast to the first embodiment option of the resiliently embodied holding elements  60  depicted in  FIGS. 9 ,  10 ,  11 ,  12 ,  13 ,  14  and  15 , the resiliently embodied holding elements  60  pursuant to the depiction in  FIG. 16  comprise hooks  88 , wherein a magnet holder  96  is configured. The magnet holder  96  is embodied as an undercut; thus enabling the permanent magnets  66  to be easily clipped into said resiliently embodied holding elements  60  pursuant to the depiction in  FIG. 16  and to immediately assume the installation position thereof. Said resiliently embodied holding elements  60  pursuant to the depiction in  FIG. 16  are preferably mounted in the radial direction, i.e. starting from the outer periphery, into the interstices  74  between the individual claw-pole fingers  24  pursuant to the depiction in  FIG. 16 . Due to their elasticity, the hooks  88  snap into correspondingly configured undercuts of the first claw-pole plate  22  and are fixedly secured in a reliable manner even when high rotational speeds and thus high centrifugal forces occur by virtue of said hooks  88  abutting against the projection which is correspondingly configured to the geometry thereof. 
         [0062]    The further embodiment option of the resiliently embodied holding element is illustrated in detail in the depiction pursuant to  FIGS. 17 ,  18  and  19 . 
         [0063]      FIG. 17  shows that a longitudinal ribbing  86 , to which in each case a clamping projection  90  is attached, is configured on the longitudinal side  68  of the resiliently embodied holding element  60 , wherein said longitudinal side  68  covers the permanent magnet  66 . The clamping projection  90 , which is embodied on the individual claw-pole fingers  24 ,  25  of the two claw-pole plates  22 ,  23 , engages in the pole grooves  92 ,  94 . It can be seen in the top view pursuant to  FIG. 17  that the longitudinal ribbing  86  can, for example, comprise two beads  98  which extend from one hook  88  to the opposing hook  88 . 
         [0064]    It can be seen in  FIG. 18  that a magnet holder  96  is situated above the hooks  88  for affixing the resiliently embodied holding elements  60  in the respective claw-pole plate  22 ,  23 . The magnet holder  96  conveys the permanent magnet  66 , which is to be pre-mounted and to be fixed by the resiliently embodied holding element  60 , into a defined position and holds it there.  FIG. 18  furthermore shows the clamping projections  90 , which extend laterally and with which the further embodiment option of the resiliently embodied holding elements  60  proposed according to the invention and depicted in  FIGS. 16 ,  17 ,  18  and  19  is fixedly secured in the interstices  74  of the claw-pole plates  22 ,  23 . 
         [0065]    It can be seen in the depiction pursuant to  FIG. 19  that this further embodiment option of the resiliently embodied holding element  60  proposed according to the invention comprises two longitudinal beads  76  running symmetrically with respect to each other, which constitute the longitudinal ribbing  86 . The resiliently embodied hooks  88  facilitate the reliable fixation of the resiliently embodied holding element  60 , which is preferably formed as a retaining plate by stamping or punching, in the claw-pole plate  22  or  23 . 
         [0066]    Whereas permanent magnets  66  substantially embodied as block-shaped are depicted in  FIGS. 5 ,  6 ,  7 ,  12  and  16 , said magnets  66  can also be embodied in geometries deviating from the rectangular shape, as, for example, having chamfered surfaces. The geometry of the permanent magnets  66  is preferably selected such that they conform to the corresponding contour of the claw-pole fingers  24 ,  25 . Two pairs of permanent magnet assemblies can thus be formed or a continuous annulus comprising all of said permanent magnets  66  can be realized via connecting plates, which enclose and give support beneath or centrally in recesses in the regions of the tips of said claw-pole fingers  24 . 
         [0067]    Whereas in the first embodiment of the resiliently embodied holding element  60  proposed according to the invention depicted in  FIGS. 4 to 15  said holding element  60  is mounted substantially from the front face  70  of the claw-pole plate  22 ,  23  axially into the interstices, the further, second embodiment of the resiliently embodied holding element  60  proposed according to the invention can be snapped in the radial direction, i.e. from the periphery, into the interstices of said claw-pole plate  22 ,  23 . 
         [0068]    In  FIG. 20A , a holding element  60  is depicted from non- or practically non-magnetic sheet metal or sheet steel, which has a wave-shaped  62  profile running transversely to the longitudinal direction of the interstice  74 . The direction considered in this instance to be a longitudinal direction runs substantially parallel to the flanks of the claw-pole fingers  24 . A wave trough  100 , whereat the permanent magnet  66  is supported on the radially outwards oriented top face thereof, is centrally located above said permanent magnet  66 . Corrugated ribs  103  profiled in the longitudinal direction, which have an edge  106  oriented radially inwards and on which said permanent magnet  66  is supported, are situated on both sides of this wave trough  100 . Tension rods  109  integrally formed on these corrugated ribs  103  and which run substantially radially inwards are situated in the longitudinal direction on both sides of said permanent magnet  66 . In the longitudinal direction at all fours corners of said permanent magnet  66 , said tension rods  109  prevent said permanent magnet  66  from displacing in the longitudinal direction relative to themselves. The holding collars  112  are in each case bent away from said permanent magnets  66  such that said collars have a substantially round profile in the longitudinal direction. Each two holding collars  112  on one longitudinal side of the permanent magnet  66  extending in the longitudinal direction align with each other and are inserted in a pole groove  92  of a claw-pole finger  24 , which is not depicted here. In order to facilitate the insertion into the two respective oppositely polarized pole grooves  92 , the holding collars  112  are provided with a chamfer  115 . A clamping bracket  64 , which with a clamping bracket  64 , which is oppositely positioned in the longitudinal direction, clamps a permanent magnet  66  between them, is situated in each case between two holding collars  112  disposed adjacently in the peripheral direction. 
         [0069]    In  FIG. 21  A, a holding element  60  is depicted from non- or practically non-magnetic sheet metal or sheet steel, which likewise has a wave-shaped  62  profile running transversely to the longitudinal direction of the interstice  74 . The direction considered in this instance to be a longitudinal direction runs substantially parallel to the flanks of the claw-pole fingers  24 . A wave trough  100 , whereat the permanent magnet  66  is supported on the radially outwards oriented top face thereof, is centrally located above said permanent magnet  66 . Corrugated ribs  103  profiled in the longitudinal direction, which merge into a holding roller  120 , are situated on both sides of this wave trough  100 . The holding rollers  120  and the holding element  60  are embodied as one piece. Said holding rollers  120  are wound in such a way that a winding end  123  abuts against said permanent magnet  66 , wherein the holding roller  120  is disposed in a pole groove  92  between a winding end  123  and the corrugated rib  103 . Said holding element  60  is supported on both sides in each case by a holding roller  120  in a respective pole groove  92 . In order to facilitate insertion, each holding roller  120  is provided with a chamfer  115  on the end faces thereof. A clamping bracket  64 , which with a clamping bracket  64 , which is oppositely positioned in the longitudinal direction, clamps a permanent magnet  66  between them, is situated in each case between two holding rollers  120  disposed adjacently in the peripheral direction. In order to reduce load peaks, a slot  126  is introduced between a holding roller  120  and a wave trough  100 . Each holding roller  120  runs preferably parallel to an edge of a block-shaped permanent magnet  66 . 
         [0070]    In  FIG. 2A , a side view of another holding element  60  from non- or practically non-magnetic sheet metal or sheet steel is depicted, which likewise has a wave-shaped  62  profile in the longitudinal direction of the interstice  74 . The holding element  60  consists of two parts, which fit snugly together at various locations. On the one hand, said holding element  60  consists of a top part  130 , which has the wave-shaped  130  profile and a clamping bracket  64  at each end. In order to facilitate insertion, the top part  130  is provided with a taper, which facilitates an insertion into the pole grooves  92 . A bottom part  136 , also see  FIG. 22B , is situated between the top part  130  and the permanent magnet  66 . On each side, respectively three arms  139  go out from this bottom part  136 , which point away from a taper  133  that is also provided on said bottom part  136 . A slot  145  is located between an arm  139  and a planar main body  142 , whereat the permanent magnet  66  is supported during operation. The arms  139  fit snugly against wave-shaped flanks  148  in the state where said top part  130  is connected and thus cause a damping friction between said top part  130  and said bottom part  136 , which counteracts vibrations and relative movements. Two lugs  151  going out from said bottom part  136  in the region of the taper  133  laterally enclose said top part  130  so as to face each other; thus enabling said top part  130  and said bottom part  136  to be connected to one another. If applicable, said bottom part  136  optionally includes a clamping bracket  64 , which, for example, is fitted to the form of the one clamping bracket  64  of said top part  130 . Both clamping brackets  64  of said top part  130  and said bottom part  136 , which are disposed at one end of said permanent magnet  66 , preferably press jointly against the one end of said permanent magnet  66 . 
         [0071]    A further holding element  60  is depicted in  FIG. 23 . This holding element  60  is created by original molds and consists, for example, of a preferably fiber-reinforced thermoplastic or thermosetting plastic. Said holding element  60  has likewise a wave-shaped  62  profile running transversely to the longitudinal direction of the interstice  74 . The direction considered in this instance to be a longitudinal direction runs substantially parallel to the flanks of the claw-pole fingers  24 . A wave trough  100 , whereat the permanent magnet  66  is supported on the radially outwards oriented top face thereof, is centrally located above said permanent magnet  66 . Profiled corrugated ribs  103 , which merge into an angle bracket  150  are situated on both sides of this wave trough  100  in the longitudinal direction. The angle brackets  150  and said holding element  60  are embodied as one piece and engage in each case in one of the pole grooves  92 . Said holding element  60  is bilaterally supported by a respective angle bracket  150 . Bays  153  extend out from the wave trough  100 , which have a planar base and abut there against one side  159  of said permanent magnet  66 . In each case, two bays  153  extend from said wave trough  100  in the direction of a pole groove  92 . Said permanent magnets  66  are engaged behind on their end faces  162  by snap-in hooks  165  integrally connected to said holding element  60  and are thereby connected to said holding element  60 . Holding arms  168 , which are considerably more pliably embodied than other regions of said holding element  60 , extend out from said angle brackets  150  in the alignment direction (pole groove  92 ). Holding lugs  171  are situated on the ends of the holding arms  168 , which by means of a mating flange surface  174  ensure a fixed position of said holding element  60  with the permanent magnet  66  in the pole grooves  92 . The holding arm  168  still engages in the pole groove  92  while the mating flange surface  174  is abutting snugly against a lateral surface of a claw-pole root. The position of the holding element  60  and consequently that of the permanent magnet  66  is definitely secured by this snug abutment against the claw-pole roots. The pole groove  92  comes to a stop in the lateral surface of the claw-pole root.