Abstract:
A rotor for an electrodynamic machine includes a laminated core having a plurality of lamination segments arranged in series in an axial direction, wherein the laminated core includes cooling ducts formed by duct spacers disposed between axially adjacent lamination segments, wherein the duct spacers are configured to resist centrifugal forces acting on the duct spacers and are supported by axial bolts extending through the laminated core in the axial direction.

Description:
[0001]    This application is a continuation application of International Application No. PCT/EP2008/053203, filed on Mar. 18, 2008, which claims priority to German Application Nos. DE 10 2007 017 537.1 and DE 10 2007 000 636.7, filed on Mar. 30, 2007 and Nov. 7, 2007, respectively. The entire disclosure of the applications is incorporated by reference herein. 
     
    
       [0002]    The invention relates to the field of electric machines. It refers to a rotor for an electrodynamic machine. 
       BACKGROUND OF THE INVENTION 
       [0003]    Stator and rotor cores of electrodynamic machines, such as generators, in most cases are formed as laminated cores which comprise lamination stacks of individual lamination segments, which stacks are held together with bolts. Slots which extend in the axial direction for accommodating the corresponding windings are arranged in the laminated cores on the inner or outer periphery. The rotor of such a machine is described for example in EP-A2-0 736 953. 
         [0004]    In the case of high-performance machines, by inserting duct spacers between adjacent stack sections of the laminated core, radial cooling ducts are formed, through which a suitable cooling medium, for example cooling air, flows in order to dissipate the heat which ensues in the winding or in the laminated core during operation. 
         [0005]    Conventional duct spacers for stators, as are known for example from publications EP-A2-0 893 871 or U.S. Pat. No. 4,362,960 or U.S. Pat. No. 6,583,526, are normally produced as double-T or rectangular profiles consisting of steel, non-magnetic steel or aluminum and are fastened on the lamination segments by means of spot-welding or adhesive bonding. 
         [0006]    For fast-rotating laminated cores of rotors, adhesive bonding or spot-welding of the duct spacers no longer suffices on account of the high centrifugal forces. 
       SUMMARY OF THE INVENTION 
       [0007]    An aspect of the present invention is to provide a rotor of the type referred to the introduction, the duct spacers of which are protected in a simple way against a harmful influence of the centrifugal forces which occur during operation. 
         [0008]    The duct spacers, in order to resist centrifugal forces which act upon them, are supported on bolts which extend through the laminated core of the rotor in the axial direction. As a result of this, a fastening of the spacer elements on the laminated core results which safely withstands the largest centrifugal forces which occur. 
         [0009]    According to one embodiment of the invention, the duct spacers extend essentially in the radial direction. 
         [0010]    Another development of the invention is characterized in that at least some of the duct spacers are formed in one piece and have a constant thickness, wherein the duct spacers of constant thickness are especially cut out of a metal sheet. The one-piece duct spacers preferably comprise in each case a widened first section which has at least one hole for inserting the axial bolts of the laminated core, and also a narrow second section in the form of a radial finger. 
         [0011]    Another development of the invention is characterized in that at least some of duct spacers are assembled in each case from a plurality of individual parts which at least partially lie one above the other, wherein the duct spacers which are assembled from a plurality of individual parts which at least partially lie one above the other preferably have the same thickness in the regions in which the individual parts lie one above the other. 
         [0012]    The assembled duct spacers preferably comprise in each case an upper part and a lower part which have in each case a widened first section with a hole for inserting the axial bolts of the laminated core, and also a narrow second section in the form of a radial finger, wherein the two parts with the first section and the hole arranged therein lie one above the other, while the fingers lie next to each other in a spaced apart manner. 
         [0013]    For adjusting to the overall thickness of the two first sections which lie one above the other the fingers especially have double thickness compared with the first sections. 
         [0014]    For doubling the thickness, in this case strip-like layers can be arranged on the fingers. 
         [0015]    Another development is characterized in that the assembled duct spacers comprise in each case an upper part and a lower part, in that one of the two parts has a widened first section with a hole for inserting the axial bolts of the laminated core, and also two narrow second sections in the form of radial fingers which lie next to each other in a spaced manner, in that the other of the two parts is formed as a perforated disk, and in that the perforated disk and the first section with the hole arranged therein lie one above the other, wherein for adjusting to the overall thickness of the first section and perforated disk which lies upon it the fingers have double thickness compared with the first section. 
         [0016]    For doubling the thickness, strip-like layers can especially be arranged on the fingers. 
         [0017]    A further development of the invention is characterized in that radial slot-like cut-outs are arranged on the outer periphery of the lamination segments, which in the case of laminated cores form the winding slots, and in that the duct spacers extend in the radial direction up to and between the slot-like cut-outs. 
         [0018]    Furthermore, it is advantageous if the duct spacers, for the support on the bolts, are additionally connected to the lamination segment by means of welding, spot-welding or pinning. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0019]    The invention is to be subsequently explained in more detail based on exemplary embodiments in conjunction with the drawing. In the drawing: 
           [0020]      FIG. 1  shows in a perspective view a rotor lamination segment with single-finger duct spacers supported on bolts, according to a first exemplary embodiment of the invention; 
           [0021]      FIG. 2  shows in two sub- FIGS. 2(   a ) und  2 ( b ) in perspective view an individual double-finger duct spacer of a first type ( FIG. 2   a ), and also a corresponding rotor lamination segment with single-finger and double-finger duct spacers ( FIG. 2   b ) supported on bolts, according to a second exemplary embodiment of the invention; 
           [0022]      FIG. 3  shows in two sub- FIGS. 3(   a ) und  3 ( b ) in perspective view an individual double-finger duct spacer of a second type ( FIG. 3   a ), and also a corresponding rotor lamination segment with single-finger and double-finger duct spacers ( FIG. 3   b ) supported on bolts, according to a third exemplary embodiment of the invention; 
           [0023]      FIG. 4  shows in two sub- FIGS. 4(   a ) und  4 ( b ) in perspective view an individual double-finger duct spacer of a third type ( FIG. 4   a ), and also a corresponding rotor lamination segment with single-finger and double-finger duct spacers ( FIG. 4   b ) supported on bolts, according to a fourth exemplary embodiment of the invention; and 
           [0024]      FIG. 5  shows in two sub- FIGS. 5(   a ) und  5 ( b ) in perspective view an individual double-finger duct spacer of a first type ( FIG. 5   a ), and also a corresponding rotor lamination segment with single-finger and double-finger duct spacers ( FIG. 2   b ) supported on bolts, according to a second exemplary embodiment of the invention. 
       
    
    
     DETAILED DESCRIPTION 
       [0025]    In  FIG. 1 , in a perspective view, a rotor lamination segment  10  with single-finger duct spacers  14  supported on bolts according to a first exemplary embodiment of the invention is shown. The lamination segment  10  has the shape of a circle segment and on the outer periphery has a number of radial slot-like cutouts  11  which, when the rotor laminated core is complete, form the axial slots for accommodating the rotor winding. Furthermore, bolt-holes  12  and  13  are provided in the lamination segments  10  on a plurality of concentric diameter circles, which serve in the laminated core for inserting corresponding bolts, as is shown in publication EP-A2-0 736 953 which is referred to in the introduction. The large bolt-holes  12  are provided for so-called rim bolts, the small bolt-holes  13  being provided for clamping bolts. 
         [0026]    A plurality of duct spacers  14 , three in the example of  FIG. 1 , are attached in radial alignment on the upper side of the lamination segment  10  and constructed in one piece, and for example are cut out from a metal sheet by means of a laser. The duct spacers  14  are formed so that both axial clamping and optimum air guiding are ensured. The duct spacers  14  are supported against the (radial) centrifugal forces, which occur during operation, on the rim bolts which are inserted in the bolt-holes  12 . This is achieved by the duct spacers  14  comprising a widened first section  15  on the inner end in each case, which has two holes in series in the radial direction which correspond to the bolt-holes  12  of the lamination segment  10 . In the laminated core the rim bolts therefore extend through the holes in the section  15  of the duct spacers  14  and securely fix them. 
         [0027]    Oriented outwards in the radial direction, the first or hole section  15  merges into a narrow radial finger  16  which extends between adjacent slot-like cut-outs  11  up to the outer edge of the lamination segment  10 . Between adjacent duct spacers  14  or fingers  16  radial ducts are thus formed in the laminated core, through which cooling air or another cooling medium can flow. The duct spacers  14  in this example have the same thickness overall. They are preferably lasered or else otherwise solidly machined from steel, antimagnetic steel, or aluminum. 
         [0028]    In the example of  FIG. 1 , the duct spacers  14  have a relatively large distance from each other in the region of the slot-like cutouts  11 : only every third tooth (region between adjacent slot-like cutouts  11 ) of the lamination segment  10  supports the finger  16  of a duct spacer  14 . In order to achieve here a much finer division of the cooling ducts, additional duct spacers can be inserted, as are reproduced in detail in  FIGS. 2 to 5  in the respective sub-figure (a). 
         [0029]    The additional duct spacers  17 ,  24 ,  27 ,  32  all have the same pincer-like basic shape, that is to say a widened inner section  20 ,  20 ′ in which a bolt-hole  21  is provided which corresponds to the bolt-hole  13 , and also two spaced-apart fingers  22 ,  23  which extend from this section  20 ,  20 ′ in the radial direction. As is apparent from the sub-figures (b) of  FIGS. 2-5 , the two fingers  22 ,  23  of the additional duct spacers  17 ,  24 ,  27 ,  32  also extend through between adjacent slot-like cutouts  11  up to the outer edge of the lamination segment  10 . In this way each slot-like cutout  11  is bordered on its two longitudinal sides by a finger in each case. 
         [0030]    The additional duct spacers  17 ,  24 ,  27 ,  32  are assembled in each case from a plurality of individual parts  18 ,  19  ( FIG. 2 ) or  18 ,  19 ,  25 ,  26  ( FIG. 3 ) or  28 ,  29 ;  30 ,  31  ( FIGS. 4 and 5 ) which at least partially lie one above the other. The duct spacers  17 ,  24 ,  27 ,  32  which are assembled from a plurality of individual parts  18 ,  19 ;  25 ,  26 ;  28 ,  29 ;  30 ,  31  which at least partially lie one above the other have the same thickness in the regions in which the individual parts  18 ,  19 ;  25 ,  26 ;  28 ,  29 ;  30 ,  31  lie one upon the other, which corresponds to the thickness of the other duct spacers  14 . 
         [0031]    In the case of the exemplary embodiments of  FIGS. 2(   a ) and  3 ( a ), the assembled duct spacers  17  or  24  comprise in each case an upper part  18  and a lower part  19  which have in each case a widened first section  20  or  20 ′ with a hole  21  for inserting the axial bolts of the laminated core, and also a narrow second section in the form of a radial finger  22  or  23 . Upper part and lower part  18  or  19  are arranged in relation to each other like the legs of dividers, wherein the bolt-holes  21  of the two parts lie one above the other and form the axis of the dividers. The fingers  22 ,  23  are constructed with double thickness compared with the first sections  20 ,  20 ′ for adjusting to the overall thickness of the two first sections  20 ,  20 ′ which lie one above the other. 
         [0032]    In the case of the embodiment which is shown in  FIG. 2 , the height of the fingers  22 ,  23  is altered in addition, which in the case of the upper part  18  increases downwards and in the case of the lower part  19  increases upwards. As a result of this, the height offset between the two fingers  22 ,  23  is compensated. 
         [0033]    In the case of the embodiment which is shown in  FIG. 3 , for doubling the thickness strip-like layers  25 ,  26  are arranged on the fingers  22 ,  23 , wherein the layer  25  is applied on the lower side in the case of the upper part  18  and the layer  26  is applied on the upper side in the case of the lower part  19 . 
         [0034]    In the case of the exemplary embodiments of  FIGS. 4 and 5 , the assembled duct spacers  27  or  32  comprise in each case an upper part  28  and a lower part  29 . The lower part  29  has a widened first section with a hole  21  for inserting the axial bolts of the laminated core, and also two narrow second sections in the form of radial fingers  22 ,  23  which lie next to each other in a spaced apart manner. The upper part  28  is formed as a perforated disk. The perforated disk  28  and the first section  20  with the hole  21  arranged therein lie one above the other. Upper and lower section can also swap places. 
         [0035]    For adjusting to the overall thickness of first section  20  and perforated disk  28  which lies above it, the fingers  22 ,  23  here are also constructed with double thickness compared with the first section  20 , which is achieved by means of strip-like layers  30 ,  31  on the fingers  22 ,  23 . The strips  30 ,  31  can be applied on the two fingers  22 ,  23  on the top ( FIG. 4   a ). However, according to the example from  FIG. 5(   a ) the strips can also be attached on the one finger  22  on the upper side and on the other finger  23  on the lower side if one of the fingers ( 23 ) is correspondingly vertically offset as a result of an S-shaped bend  33 . 
         [0036]    The duct spacers  14 ,  17 ,  24 ,  27 ,  32  in addition to the support on the bolts can be connected to the lamination segment  10  by means of welding, spot-welding or pinning. 
       LIST OF DESIGNATIONS 
       [0000]    
       
           10  Lamination segment (rotor) 
           11  Slot-like cut-out 
           12  Bolt-hole (rim bolt) 
           13  Bolt-hole (clamping bolt) 
           14 ,  17 ,  24 ,  27 ,  32  Duct spacer 
           15  Hole section 
           16  Finger (radial) 
           18  Upper part 
           19  Lower part 
           20 ,  20 ′ Hole section 
           21  Bolt-hole 
           22 ,  23  Finger (radial) 
           25 ,  26  Layer (strip-like) 
           28  Upper part 
           29  Lower part 
           30 ,  31  Layer (strip-like) 
           33  Bend (S-shaped)