Abstract:
An apparatus for routing cables in wind turbines has a plurality of bushings ( 17 ) for cables distributed on at least one base body ( 3, 5 ) that has a preferably round contour. The bushings ( 17 ) are provided with a guiding arrangement ( 27; 38; 39, 41; 43; 48 ) permitting the cables to move relative to the part of the bushing ( 17 ) that surrounds the guiding arrangement.

Description:
FIELD OF THE INVENTION 
     The invention concerns an apparatus for routing cables in wind turbines, in which on at least one base body having a preferably circular outline, multiple cable bushings are distributed. 
     BACKGROUND OF THE INVENTION 
     For the purpose of discharging the energy generated in wind turbines, as well as for other operational purposes such as control, monitoring etc., the cables that extend down through the tower from the nacelle must be routed such that when the cables, which hang in form of cable bundles from the nacelle inside the tower, move during operation they are not damaged or impaired in any way. Since in commonly used wind turbines the nacelle with the generator unit, from which the cable bundle hangs inside the tower, can make up to three turns before the nacelle is driven back, the cable bundle must be routed such that the cables inside the bundle, hanging in the tower, are, on the one hand, able to follow the movement, but, on the other hand, do not chafe against each other to the degree that the insulation may be damaged. 
     To this end, in the prior art, for example as described in WO 2011/151465 A2, the cables are led, spaced from each other, from the rotatable nacelle in a cable bundle to a base body that is non-rotatably supported inside the tower. The cables are fed through bushings arranged on the base body. The bushings are disposed in the base body, spaced from each other, so that the cables inside the bundle are also spaced from each other. As the bundle twists with the rotating movement of the nacelle, the danger of chafing between the cables is largely prevented. Nevertheless, the sudden change in direction of the cables, which is caused by the twisting of the bundle at the location where the cable exits the bushings of the base bodies, leads to undue local stress on the cables and their insulation. 
     SUMMARY OF THE INVENTION 
     An object of the invention to provide an improved guiding apparatus that ensures the best possible protection of the cables during the twisting movements of the cable bundle. 
     This object is basically achieved according to the invention by an apparatus where the bushings are provided with a guiding arrangement, which permits cable movements relative to the part of the bushing that surrounds the guiding arrangement. This arrangement prevents the cables from being forced at the exit from the bushing into a sudden change in direction that is similar to kinking, since the free movement within the bushing permits a gradual change in direction. 
     In particularly advantageous exemplary embodiments, the respective guiding arrangement is provided with an insert that surrounds the cable passing through. The insert is moveably supported in the respective bushing relative to the base body. 
     In particularly preferred exemplary embodiments the insert is made in form of an annular body that surrounds the cable passing through it. The outside surface of the annular body forms part of a convex, spherical surface on which a part of a wall of the inside of the bushing is supported, forming a spherical cap. This structure creates a ball joint-shaped guide for the cable, providing the cable with freedom to move around any axes. 
     Alternatively, the guiding arrangement can be fitted with an elastomeric, annular body that flexibly surrounds the cable in the bushing, preferably made of a synthetic rubber material. The guiding of the cable through a type of collar can be achieved with little effort and is a very cost-effective solution. 
     According to a further advantageous exemplary embodiment, the guiding arrangement is provided with a swivel bearing for the cable passing through. To this end the arrangement may be implemented with particular advantage in that the swivel bearing is provided with a needle bearing, with its inner ring surrounding the passing cable and its outer ring fixed to the base body. This structure allows the cables that pass through it to adjust their turning position to the rotating movements of the bundle in a particularly gentle manner. 
     In an alternative exemplary embodiment the guiding arrangement may comprise rotatable roller bodies that are arranged such that they form lateral boundaries of the cable passage of the respective bushing. Hence, the bushing for the passing cable is provided with moveable walls. 
     In a particularly simple and cost-effective solution, the bushings can be formed by circular openings in a circular disk that forms the base body. The guiding arrangement is formed by the openings in the base body. The wall of the openings curve and expand outwards on both sides. Thus, each cable that passes through the bushing is able to adjust to any inclination relative to the plane of the base body. 
     In a further modified exemplary embodiment, the base body is provided, along its circular circumference, with adjacently located holding fixtures that are radially open in outward direction. The holding fixtures are provided for the purpose of inserting and retaining bushings whose cable passages can be opened to allow the insertion of the respective cable. Such exemplary embodiments are characterized by being particularly easy to install, since the threading of individual bundle elements through closed cable passages is not necessary. This structure also enables easy retrofitting in existing plants. 
     In particularly advantageous exemplary embodiments, the bushings are formed by two partial bodies that delimit the opening of the cable passage so that the cable passages can be opened. The two partial bodies can be locked in the respective holding fixture in a position that closes the opening. 
     The partial bodies may be shaped as identical parts, each of which forms one half of the bundle bushing. 
     To securely lock the bushings in the holding fixtures, advantageous exemplary embodiments are provided with a locking strap that surrounds the circumference of the base body and fits tightly against the bushings, in radial direction on the outside located, partial bodies of the bushings. 
     To account for the cable bundle becoming shorter as it twists, particularly advantageous exemplary embodiments provide at least one base body. Attached to the swiveling nacelle located on the tower of the respective wind turbine. At least one base body disposed further down is attached such that it is non-rotatable and vertically moveable inside the tower. 
     In this respect, particularly advantageously, radially protruding rollers are provided on the edge of the vertically moveable base body at diametrically opposed locations. The rollers are guided in vertical runners inside the tower. The base body is thus non-rotatably supported with respect to the tower, but it is able to assume the appropriate vertical position depending on the respective length of the cable bundle. 
     Other objects, advantages and salient features of the present invention will become apparent from the following detailed description, which, taken in conjunction with the drawings, discloses preferred embodiments of the present invention. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       Referring to the drawings that form a part of this disclosure: 
         FIG. 1  is a schematically simplified side view of a cable bundle hanging from the nacelle of a wind turbine inside the tower and guided by an apparatus according to an exemplary embodiment of the invention; 
         FIG. 2  is a schematically simplified side view of the cable bundle of  FIG. 1  shown in a twisted state; 
         FIG. 3  is a perspective view of a base body according to a first exemplary embodiment of the apparatus according to the invention, in which the base body is supported non-rotatably and vertically moveable inside the tower; 
         FIG. 4  is an enlarged, partial side view in section of the base body taken along line IV-IV of  FIG. 3 ; 
         FIG. 5  is a perspective view of a base body according to a second exemplary embodiment of the apparatus according to the invention; 
         FIG. 6  is a perspective view in section of the base body of  FIG. 5 ; 
         FIG. 7  is a perspective view of a base body according to a third exemplary embodiment of the apparatus according to the invention; 
         FIG. 8  is an enlarged partial perspective view in section of the base body according to a fourth exemplary embodiment of the apparatus of the invention; 
         FIG. 9  is a perspective view of a base body according to a fifth exemplary embodiment of the apparatus of the invention; 
         FIG. 10  is a perspective view of a base body according to a sixth exemplary embodiment of the invention; 
         FIG. 11  is a perspective view of a base body according to a seventh exemplary embodiment of the apparatus of the invention, similar to that of  FIG. 3 ; 
         FIG. 12  is a plan view of the base body of  FIG. 11 ; 
         FIG. 13  is a side view in section taken along line XIII-XIII of  FIG. 12 ; 
         FIG. 14  is a separated perspective view of an annular body in a two-part design of  FIG. 11 ; 
         FIG. 15  is a partial perspective view of only the base body and a single runner according to an eighth exemplary embodiment of the invention; 
         FIG. 16  is an enlarged partial perspective view in section of the exemplary embodiment of  FIG. 15 ; 
         FIGS. 17 &amp; 18  are perspective views of the sliders provided in the embodiment of  FIGS. 15 and 16 , providing the rear view and the front view of the depicted slider, respectively; 
         FIG. 19  is a perspective view of a base body according to a ninth exemplary embodiment of the invention, similar to that of  FIGS. 5 and 10 ; 
         FIG. 20  is a plan view of the base body of the exemplary embodiment of  FIG. 19  shown separately without bushings inserted; 
         FIG. 21  is an enlarged perspective view of a single bushing of  FIG. 19 ; 
         FIG. 22  is a perspective view of the bushing of  FIG. 21  in which the two partial bodies of the bushing are pulled apart; and 
         FIG. 23  is a partial, perspective view in partial section, drawn to the same scale as  FIGS. 21 and 22 , showing a bushing inserted into a holding fixture of the base body in the embodiment of  FIG. 19 . 
     
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
       FIGS. 1 and 2  depict an exemplary embodiment of the guiding arrangement according to the invention, showing only a cable bundle  1  handing from a nacelle into a tower. The components of the guiding arrangement according to the invention that interact with the cable bundle  1 . The remaining components of the respective wind turbine, such as nacelle, rotor, tower etc. are not shown in the present drawings since they may be of a standard design. The cable bundle  1  is guided between an upper base body  3  attached to the rotatable nacelle (not shown) and is vertically unmovable, and a lower base body  5  non-rotatably fixed to the tower (not shown) but vertically moveable. 
     To this end a pair of rollers  7  is provided on each of diametrically opposed locations of the lower base body  5 . The rollers  7  of each pair are vertically offset to one other and are guided in runners  9  that are attached to the tower and extend in vertical direction. While in  FIG. 1  the cable bundle  1  is shown in a non-twisted, stretched state,  FIG. 2  shows the state in which the nacelle, and thus the upper base body  3 , have swiveled so that the cable bundle  1  is twisted. Due to the shortening of the cables caused by the twisting, the lower base body  5  in  FIG. 2  has moved vertically upwards along runners  9  to compensate for the change in length. The design of the upper base body  3  can be the same as that of the lower base body  5  with the exception that rollers  7  with the respective brackets are attached to the lower base body  5 . 
       FIGS. 3 and 4  show the design of the base body  5  according to a first exemplary embodiment of the apparatus according to the invention in greater detail. The base body  5  comprises an intermediate body in form of a disk  11 , which, starting from a center section with a central opening  13 , is provided with radially outwardly extending spokes  15  (see  FIG. 4 ). Spokes  15  leave room between them for bushings  17 , which in the present example has eight bushings  17  evenly distributed along a circle. The bushings  17  are each formed between the spokes  15  by circle segments  19 , which are secured from both sides to disk  11 . The circle segments  19  fit together neatly without gaps therebetween. Due to their arc-shaped peripheral edge, circle segments  19  provide the base body  5  with a circular outline or periphery. To ensure that the circle segments  19  form a ring structure where the abutting circle segments  19  are locked together, a locking strap  21  is placed around the outer circumference of the structure, which locking strap  21  can be tensioned by a turnbuckle  23 . 
     As is most clearly apparent from  FIG. 4 , the wall  25  of the circle segments  19 , which delimits the cable passage of the formed bushing  17 , has a concave shape that forms a portion of a spherical cap. An insert, which surrounds the cable that passes through the respective bushing  17 , takes the shape of an annular body  27  the outside of which forms part of a convex spherical surface  29  (see  FIG. 4 ). The annular body  27  lies against the concave wall  25  of circle segment  19 . Thus, the annular body  27 , which forms the insert, is supported on the respective base body  3 ,  5  like a ball joint so that the cable running through the bushings  17  can take on any inclination with respect to the plane of the base body  3 ,  5  and can also twist together with the insert (annular body  27 ). 
       FIGS. 5 and 6  depict a further exemplary embodiment, which differs from the previously described example mainly in that a disk  31  is provided that is not star-shaped, as is the case with the disk  11  of the previously described example, but forms with the outer edge  33  itself the circular outline of the base body  3 ,  5 . Apart from the central opening  13 , further openings in disk  31  are provided to form the bushings  17 . As in the previously described example, the guiding arrangement of the bushings  17  is each formed by an insert in form of an annular body  27 , the outside of which is again part of a spherical surface  29 . 
     In the example of  FIGS. 5 and 6 , ring elements  35  are attached to the lower and upper sides of the disk  31 , instead of the circle segments  19  provided in the previously described example. The ring elements  35  again are provided, like the circle segments  19  of  FIGS. 3 and 4 , with internally concave walls  37  so that the annular bodies  27  are supported similar to ball joints. This embodiment does not provide a locking strap that surrounds the circumferential edge  33  of the disk  31 . A further difference is that the central opening  13  of disk  31  can also be used to form a bushing  17  because this opening  13  is also provided with ring elements  35  with a cap-like curved inner wall  37 . A ball joint-like guiding arrangement can then be formed through inserted annular bodies  27 . 
       FIG. 7  shows a further modified exemplary embodiment in which, again, a disk  31  is provided with an outer edge  33  that determines the circular outline. A rubber ring is inserted as a guiding arrangement into each of the openings provided for the bushings  17 . This structure provides flexible guidance for the cable in an elastomeric collar so that the cable is able to assume the required inclination with respect to the plane of disk  31 . 
     In a further exemplary embodiment shown in  FIG. 8 , a disk  31  with a circumferential edge  33  is provided. The guiding arrangement of the bushings  17  is formed in each case through a swivel bearing for the cable bundle, in which a needle bearing is provided The outer ring  39  of each needle bearing is fixed to the disk  31 . Its inner ring  41  surrounds the respective cable bundle. 
       FIG. 9  shows a further modified exemplary embodiment in which, again, a disk  31  is provided, which disk defines the circular outline of the base body  3 ,  5  with its outer edge  33 . Triangular-shaped openings are formed in disk  31  for the bushings  17 . Rotatable cylindrical roller bodies  43  are arranged on the sides of the triangles, at the top and at the bottom of the disk  31 . The cylindrical roller surfaces then form the contact surface for the respective cable passing through it. The guiding arrangement of this design also provides possibilities for the inserted cable to carry out movements relative to the remaining part of the base body  3 ,  5 . 
       FIG. 10  depicts an exemplary embodiment that is characterized by a particularly simple design. The single-piece main component of base body  3 ,  5  is in this instance a circular plate  45  that comprises round openings  47  for the bushings  17 . The guiding arrangement for the cables passing through it is in this instance formed by giving the wall of the opening  47  a special shape. Curvatures  49  enlarge the openings  47  towards the outside and thus provide the passing cable with a predefinable inclination on exiting the openings. 
     The details of the base bodies  3 ,  5  are described in  FIGS. 2 to 8 and 10  with base body  5 , being fitted with rollers  7  and being arranged non-rotatably below base body  3 , which can rotate together with the nacelle. All of the described designs of the base body without lateral rollers  7  can also be used as the upper base body  3 , as shown in the example depicted in  FIG. 9 . 
     The  FIGS. 11 to 13  show a further exemplary embodiment in which the base body  5  is formed from two identical disks  51  that are arranged one on top of the other. The disks  51  form a star-shaped body with a slot on one side, so that the bushings  17 , which are arranged along the perimeter of disks  51 , are open to the outside via slots  53  (not all have reference numbers). 
       FIG. 14  shows a modified embodiment of the annular bodies  27 . As depicted, the annular bodies  27  are formed from two identical ring halves  55  that can be attached to each other by pins  57  protruding from the connecting surfaces, and their matching bores  59 . 
     When describing the bushings  17  in base body  3 ,  5  above, it does not only mean bushings that are arranged inside the base body, but also those that are arranged along the edge (not shown), which provide cable guidance with a further degree of freedom compared to the known, rigid guide designs. Provided that the base body has a slot at the edge in the vicinity of the bushings, the insertion of a cable from the side via the slot is possible. 
     The  FIGS. 15 to 18  show a further exemplary embodiment in which the base body  5  is formed by a circular plate  45 , as in  FIG. 10 . In contrast to  FIG. 10 , however, the plate  45  is not moveably guided by f pairs of rollers  7  on runners  9 . Each pair of rollers  7  is replaced by a slider  71  the shape of which can be seen in detail in  FIGS. 17 and 18 . The runners  9 , of which only one is shown in  FIGS. 15 and 16 , take the shape of a C-shaped cross sectional profile in contrast to the example in  FIG. 3 , in which the runners  9  are shaped as a U-profile in cross section. The sliders  71  are injection-molded from plastic as a single piece and are comprise a front sliding shoe  73  and a rear guiding part  75 . The sliding shoe  73  forms parallel guiding surfaces  77  with which the slider  71  is guided inside the open slot of the C-profile of runners  9 . Moreover, the guiding part  75  serves as an attachment having bolt holes  79  extending all the way to the front side of sliding shoe  73  and end in expanded hexagonal recesses  81 . Recesses  81  are designed to receive the hexagonal head of mounting bolts  83 . As is best seen in  FIG. 16 , the mounting bolts  83  are used to fasten the respective slider  71  to brackets  85 , which are formed from folded sheet metal, and which in turn are bolted to the plate  45 . 
     As shown in  FIGS. 17 and 18 , the sliders  71  are provided at the front with convex-curved sliding surfaces  87  ( FIG. 18 ) and on the back with corresponding convex-curved sliding surfaces  89  ( FIG. 17 ), with which the sliders  71  are guided along the inner wall of the C-profile of runners  9 . The curvature of the sliding surfaces  87  and  89  allows plate  45  to slant to permit a limited angular pulling of the cables, which have been inserted into bushings  17 , without tilting. 
     The  FIGS. 19 to 23  show a further exemplary embodiment of the invention, which differs from the previously described examples mainly in that the bushings  17  are designed such that the opening  47 , formed to allow the bundle elements to pass through, can be opened. Moreover, the bushings  17  are arranged such on the periphery of the base body  5  that, in the open state of opening  47 , bundle elements can be inserted from the outside of the base body  5  before the opening  47  is closed. 
       FIG. 19  shows this exemplary embodiment without inserted bundle elements, with the bushings  17  in the closed state. The bushings  17  are arranged along the perimeter of base body  5 . The assembly is held together by a locking strap  21  placed around the outside, as per the example shown in  FIG. 3 . The locking strap  21  in the present example can be closed or opened through a quick-release fastener  22  without using tools. 
     The  FIG. 20  shows the base body  5  separately without inserted bushings  17 . The base body  5  is designed as a star-shaped body, preferably made from injection-molded metal alloy. The base body  5  comprises an internally located, non-circular ring element  24 , presently in the form of an octahedron. An attachment  26  extends radially from each of the eight corners  18 , away from the center of the ring element  24 . The attachments  26  are approximately triangular in shape, each with two arms  28  extending from the corners  18 . The arms  28  are connected to each other through braces  30  at their radially outer ends and in a center section. The arms  28  of adjacent attachments  26  extend parallel to each other and demarcate between them and the ring element  24  a holding fixture  32  for a bushing  17  to be inserted there. 
     The  FIGS. 21 to 23  show the bushings  17  in greater detail. Each bushing  17  has two partial bodies  34  that are injection-molded from plastic as identical parts. Every partial body  34  forms a clamp which, in a closed position, as shown in  FIG. 21 , forms one half of the opening  47 , which is the bundle passage. In the closed position, as shown in  FIG. 22 , the pins  36  and the bore holes  40  engage at their respective contact surface. This structure provides mutual guidance to compensate for manufacturing tolerances. On the two sides that are facing the arms  28  when the partial bodies  34  are inserted into the holding fixture  32  in operating position, the partial bodies  34  each form a channel  42  (see  FIG. 21 ) laterally delimited by guiding rails  44 . When inserting the bushings  17  into the holding fixtures  32 , the respective arm  28  of the attachment  26  of base body  5  is received in the respective channel  42 . Bevels  46  at the end of the guiding rails  44  facilitate the sliding of the bushings  17  onto the arms  28 . A flexible latching clasp  48  is formed inside each of the channels  42  on each partial body  34 . A catch  50  protruding to the outside is located in close proximity to the flexible, free end of the latching clasp  48 . As can be seen from  FIG. 20 , and in particular from  FIG. 23 , each catch  50  is provided to interact with latching grooves  62  located on the arms  28  of the attachments  26  of base body  5 . A channel  64 , which is laterally bounded by a rib structure  66 , is also formed on the other sides for the engagement of the ring element  24  of base body  5 , as shown in  FIG. 21 , top and bottom, and in  FIG. 22  on the side. 
     For the installation of the bushings  17  in this design, a partial body  34  is pushed onto the respective arms  28 , where that partial body  34  interlocks with the latching grooves  62  that are adjacent to annular body  24 , and is thus already prevented from slipping out. The bundle elements can now be inserted easily from the outside. The second partial body  34  is subsequently pushed onto the arms  28  to close the opening  47 , which causes the locking of the outer latching grooves  62 , thus preventing the bundle elements from falling out of the holding fixtures  32 . To completely secure the thus formed unit, a locking strap  21  can be placed around the outside and secured by way of the quick-release fastener  22 . As shown in  FIG. 19 , the rollers  7  in this exemplary embodiment that are provided for guidance in the runners  9  in the tower are, differently to the above described examples, not attached to the base body  5 , but are attached to the locking strap  21 . 
     While various embodiments have been chosen to illustrate the invention, it will be understood by those skilled in the art that various changes and modifications can be made therein without departing from the scope of the invention as defined in the claims.