Patent Publication Number: US-10774673-B2

Title: Guide vane adjustment device and turbomachine

Description:
CROSS REFERENCE TO RELATED APPLICATIONS 
     This is a U.S. national stage of application No. PCT/EP2016/058181, filed on Apr. 14, 2016. Priority is claimed on German Application No. DE102015004648.9, filed Apr. 15, 2015, the content of which is incorporated here by reference. 
     BACKGROUND OF THE INVENTION 
     1. Field of the Invention 
     The invention is directed to a guide vane adjusting device for a flow machine and a flow machine with a guide vane adjusting device of this type. 
     2. Description of the Prior Art 
     Flow machines known from practice have a rotor and a stator. The rotor of a flow machine comprises a shaft and a plurality of blades rotating together with the shaft. The blades form at least one rotor blade ring. The stator of a flow machine comprises a housing and a plurality of stationary guide vanes, these guide vanes forming at least one guide vane ring. 
     It is known from practice to adjust the guide vanes of a guide vane ring of a flow machine via a guide vane adjusting device such that the guide vanes are rotatable around a guide vane axis extending in radial direction of the rotor. 
     Guide vane adjusting devices known from practice have a driveshaft to which a drive motor can be coupled that is drivable via the drive motor. In guide vane adjusting devices known from practice, the rotation of the driveshaft via the drive motor is transmitted by a control ring to all of the guide vanes of a guide vane ring such that all of the guide vanes of a guide vane ring are accordingly adjusted or rotated indirectly proceeding from the driveshaft with the intermediary of the control ring. The control ring of guide vane adjusting devices known from practice is rotatable in circumferential direction, but is not displaceable in axial direction or radial direction. 
     Guide vane adjusting devices known from practice have the drawback that they incur a relatively large amount of friction. Further, they are subject to a high torsional load. Therefore, guide vane adjusting devices known from practice must have correspondingly large dimensions. However, this is disadvantageous in view of the limited installation space available in flow machines. 
     SUMMARY OF THE INVENTION 
     In view of the foregoing, an objective upon which one aspect of the invention is based is to provide a novel guide vane adjusting device for a flow machine and a flow machine with a guide vane adjusting device of this kind. 
     The driveshaft is directly coupled with one of the guide vanes of the guide vane ring such that this guide vane of the guide vane ring is directly rotatable proceeding from the driveshaft without an intermediary of a control ring. The driveshaft, or the guide vane that is directly drivable by the driveshaft, is coupled with the control ring in an articulated manner via a transmission lever. The driveshaft is indirectly coupled with the other guide vanes of the guide vane ring such that the other guide vanes of the guide vane ring are indirectly rotatable proceeding from the driveshaft with the intermediary of the control ring. The guide vanes that are indirectly drivable by the driveshaft are coupled with the control ring in an articulated manner via further transmission levers. The control ring is displaceable in circumferential direction and in axial direction such that forces at coupling points between the control ring and the transmission levers, which are coupled with the control ring in an articulated manner, run perpendicular to the transmission levers. 
     The above-mentioned features combined with one another make it possible to lessen the incidence of friction and torsional loading. One of the guide vanes of a guide vane ring is directly rotatable by the driveshaft without the intermediary of the control ring. The other guide vanes of the guide vane ring are indirectly rotatable proceeding from the driveshaft with the intermediary of the control ring. The guide vane that is directly rotatable or directly coupled with the driveshaft is coupled with the control ring in an articulated manner via a transmission lever. Further, the guide vanes of the guide vane ring, which are indirectly rotatable or indirectly coupled with the driveshaft, are coupled with the control ring in an articulated manner via transmission levers. The control ring is guided so as to be displaceable in circumferential direction and in axial direction and is nondisplaceably guided exclusively in radial direction. In this way, it can ultimately be ensured that forces at the coupling points between the control ring and the transmission levers coupled with the control ring in an articulated manner always run perpendicular to the transmission levers so that bearings of the guide vanes are not loaded by parasitic force components. In this way, a guide vane adjusting device can ultimately be dimensioned smaller so that its installation space requirement is reduced. 
     According to an advantageous further development of the invention, the driveshaft or the guide vanes that are directly drivable by the driveshaft is/are coupled with the control ring in an articulated manner via a transmission lever comprising multiple parts, a first segment of the multiple-part transmission lever being rigidly coupled with the driveshaft or with the guide vanes that are directly drivable by the driveshaft, and a second segment of the multiple-part transmission lever is coupled in an articulated manner with the control ring. The first segment of the multiple-part transmission lever is preferably coupled in an articulated manner with the second segment of the multiple-part transmission lever so as to form a two-part transmission lever. This allows the driveshaft or the guide vanes that are directly drivable by the driveshaft to be coupled with the control ring in a particularly advantageous manner. 
     According to a first variant of the invention, the guide vanes that are indirectly drivable by the driveshaft are coupled in an articulated manner with the control ring via one-part, elastically deformable transmission levers. Alternatively, according to a second variant of the invention, the guide vanes that are indirectly drivable by the driveshaft are coupled with the control ring in an articulated manner via multiple-part transmission levers, and a first segment of each of these multiple-part transmission levers is rigidly coupled with the respective guide vane, and a second segment of each of these multiple-part transmission levers is coupled in an articulated manner with the control ring. In the second variant, the first segment of the respective multiple-part transmission lever is then preferably coupled in an articulated manner with the second segment of the respective multiple-part transmission lever to form a two-part transmission lever. These two variants allow an advantageous coupling of the indirectly rotatable guide vanes to the control ring. The first variant with the one-part transmission levers between the control ring and the guide vanes which are indirectly drivable by the driveshaft is simpler with respect to construction than the second variant with the multiple-part transmission levers. However, the second variant with the multiple-part transmission levers is a more compact construction. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       Preferred further developments of the invention are indicated in the subclaims and following description. Without limiting generality, embodiment examples of the invention will be described more fully with reference to the drawings. The drawings show: 
         FIG. 1  is a perspective view of a detail from a flow machine in the region of a guide vane ring and a guide vane adjusting device for the guide vanes of the guide vane ring; 
         FIG. 2  is a top view of the arrangement from  FIG. 1  in a first condition; 
         FIG. 3  is a sectional side view from  FIG. 2 ; 
         FIG. 4  is a top view of the arrangement from  FIG. 1  in a second condition; 
         FIG. 5  is a sectional side view from  FIG. 4 ; 
         FIG. 6  is a partial cross section through an alternative guide vane adjusting device; 
         FIG. 7  is a partial cross section through the guide vane adjusting device of  FIG. 6  offset by 90° relative to  FIG. 1 ; 
         FIG. 8  is a perspective view of the arrangement from  FIG. 7  without a housing; 
         FIG. 9  is a detail from  FIG. 8 ; 
         FIG. 10  is a detail of the guide vane adjusting devices; 
         FIG. 11  is an alternative to the detail from  FIG. 10 ; 
         FIG. 12  is an alternative to the arrangement in  FIG. 8 ; 
         FIG. 13  is a detail from  FIG. 12 ; and 
         FIG. 14  is an alternative to the detail in  FIG. 13 . 
     
    
    
     DETAILED DESCRIPTION OF THE PRESENTLY PREFERRED EMBODIMENTS 
     The present invention is directed to a guide vane adjusting device for a flow machine and to a flow machine with at least one guide vane adjusting device of this type. 
     The basic construction of a flow machine will be familiar to the person skilled in the relevant art. It is noted here for the sake of completeness that a flow machine includes a rotor with rotor-side guide blades and a stator with stator-side guide vanes. 
     The guide blades of the rotor form at least one guide blade ring, and the guide blade ring or each guide blade ring rotates together with a shaft of the rotor. The guide vanes of the stator form at least one guide vane ring that is connected to a stator-side housing. 
       FIG. 1  shows a section from a flow machine in the region of a guide vane ring  20  having a plurality of guide vanes  21 . Each of the guide vanes  21  has a vane root, or vane pin  22 , and a vane blade  23 , the vane pin  22  of the respective guide vane  21  being positioned radially outwardly and engaging at a housing structure  24  of the flow machine. 
     The present invention is directed to a guide vane adjusting device for the guide vanes  21  of a guide vane ring  20  of the above-mentioned type by which the guide vanes  21  can be rotated around guide vane axes  25  of the guide vanes  20 , which guide vane axes  25  extend in radial direction of the rotor of the flow machine. 
     The vane roots  22  of the guide vanes  21  are accordingly rotatably mounted in the housing structure  24 , namely such that each of the guide vanes  21  can be rotated around the respective guide vane axis  25  extending in radial direction. 
     The guide vane adjusting device for the rotation of the guide vanes  21  of the guide vane ring  20  around their guide vane axes  25  extending in radial direction comprises a driveshaft  26  that can be coupled to a drive motor, not shown, and which is drivable proceeding from the drive motor. 
     The driveshaft  26  is directly coupled to one of the guide vanes  21  of the guide vane ring  20 , namely, such that this guide vane  21  of the guide vane ring  20  is directly rotatable proceeding from the driveshaft  26 . 
     The driveshaft  26  preferably extends coaxial to the vane pin  22  of this directly rotatable guide vane  21  and coaxial to the vane axis  25  of this directly rotatable guide vane  21 . 
     The guide vane adjusting device further comprises a control ring  27 . The driveshaft  26 , or the guide vane  21  that can be directly driven by the driveshaft  26 , is coupled with the control ring  27  in an articulated manner via a transmission lever  28 . 
     The driveshaft  26  is indirectly coupled with the other guide vanes  21  of the guide vane ring  20  via the control ring  27  such that the rest of the guide vanes  21  of the guide vane ring  20  are indirectly rotatable proceeding from the driveshaft  26 , namely, with the intermediary of the control ring  27  that transmits the rotation of the driveshaft  26  to the rest of the guide vanes  21  of the guide vane ring  20 . These guide vanes  21  of the guide vane ring  20  which are indirectly drivable and rotatable proceeding from the driveshaft  26  are coupled with the control ring  27  in an articulated manner via further transmission levers  29 . 
     The control ring  27  to which the guide vanes  21  that are directly adjustable proceeding from the driveshaft  26  are connected via the transmission lever  28  on the one hand and to which the guide vanes  21  that are indirectly rotatable proceeding from the driveshaft  26  are connected via the transmission levers  29  on the other hand is displaceable in circumferential direction U and in axial direction A. Owing to this displaceability of the control ring  27  in circumferential direction U and in axial direction A and owing to the articulated connection of the transmission levers  28  and  29  to the control ring  27 , forces acting during the rotation of the guide vanes  21  at the coupling points between the control ring  27  and the transmission levers  28 ,  29  which are coupled in an articulated manner with the control ring  27  always run perpendicular to the transmission levers  27 ,  28 . 
     As a result of the above-mentioned features of the guide vane adjusting device, friction at the latter is reduced, and parasitic force components that act on the transmission levers in the prior art are prevented. As a result, bearings  30  of the guide vanes via which the latter are rotatably mounted in the housing structure  24  are less highly loaded. Referring to  FIG. 6 , each guide vane is radially and axially mounted at two locations by means of two bearings  30 . 
     The driveshaft  26 , or the guide vane  21 , particularly the vane pin  22  thereof, which is directly drivable by the driveshaft, is coupled with the control ring  27  in an articulated manner via a multiple-part transmission lever  28 . This multiple-part transmission lever  28  has at least one first segment  31  rigidly coupled with the driveshaft  26  or with the guide vane  21 , which is directly drivable by the driveshaft  26 , and a second segment  32  coupled with the control ring  27  in an articulated manner. This transmission lever  28 , which serves to couple the directly rotatable guide vane  21  and driveshaft  26 , respectively, to the control ring  27 , is preferably formed as a two-part transmission lever, in which case the first segment  31  and the second segment  32  of the same are coupled in an articulated manner. In the preferred embodiment example shown here, two spherical joint bearings  33  are formed between the first segment  31  of the two-part transmission lever  28  and the second segment  32  of the latter. Further, another spherical joint bearing  34  is formed between the second segment  32  of this transmission lever  28  and the control ring  27 . 
     In the embodiment examples of the guide vane adjusting device shown in  FIGS. 1 to 9 , the guide vanes  21  that are indirectly drivable proceeding from the driveshaft  26  are coupled with the control ring  27  via the transmission levers  29 , which are also formed as multiple-part transmission levers  29  in the embodiment examples in  FIGS. 1 to 9 . Each of these transmission levers  29  has a first segment  35  rigidly coupled with the respective guide vane  21  and a second segment  36  coupled with the control ring  27  in an articulated manner. In the embodiment examples in  FIGS. 1 to 9 , these transmission levers  29  as well as transmission lever  28  are also constructed as two-part transmission levers  29 . In this case, the first segment  35  of the respective transmission lever  29  is connected in an articulated manner with the second segment  36  of the transmission lever  29 . According to the embodiment examples shown in  FIGS. 1 to 9 , two spherical joint bearings  37  are formed between the first segment  35  of the respective transmission lever  29  and the respective second segment  36  thereof, and a spherical joint bearing  38  is formed between the second segment  36  of the respective transmission lever  29  and the control ring  27 . 
     As has already been stated, the control ring  27  is displaceable in circumferential direction and axial direction relative to the housing structure  24  and is guided and fixed only in radial direction.  FIGS. 10 and 11  show a control ring  27  of this type by itself. An inner running surface  39  of the control ring  27  in  FIG. 10  is preferably coated with sliding lacquer or a PTFE fabric in order to reduce friction at the control ring  27 . 
       FIG. 11  shows an alternative construction of the control ring  27  formed of multiple parts rather than one part as in  FIG. 10  and which comprises a plurality of sliding pads  40  that are detachably connected to a base body  41  of the control ring  27  in  FIG. 11 . The sliding pads  40  prevent a tilting of the control ring  27  during a movement thereof in axial direction and circumferential direction and allow the control ring  27  to be fitted to the housing structure  24  so as to be free of play. The sliding pads  40  are exchangeable and are preferably made from a material with good sliding properties and, accordingly, low friction coefficients. The sliding pads  40  are connected with the base body  41  in an articulated manner via sliding pad holders  40   a  such that they are supported in each instance so as to be rotatable around an axis extending tangential to the circumference and perpendicular to the rotational axis of the control ring  27 . 
     As has already been stated, all of the transmission levers  28 ,  29  in the embodiment examples shown in  FIGS. 1 to 9 , i.e., on the one hand, transmission lever  28 , which couples the driveshaft  26  or the guide vane  21  directly driven by the driveshaft  26  to the control ring  27  and, on the other hand, transmission levers  29 , which couple the control ring  27  to the guide vanes  21  indirectly driven proceeding from the transmission shaft  26 , are constructed of two parts in each instance. Three spherical joint bearings are formed in the region of each of the transmission levers  28 ,  29  so that, as can be seen particularly from a comparison of  FIGS. 3 and 5 , it is possible to compensate a height offset or radial offset between the respective transmission lever  28 ,  29  and the control ring  27 , which varies during the rotation and axial displacement of the control ring  27 . 
       FIGS. 12 to 14  show embodiment examples of the invention in which the transmission levers  29 , which serve to couple the guide vanes  21  indirectly driven by the driveshaft  26  to the control ring  27 , are formed as one-part, resiliently elastically deformable transmission levers  29 . Accordingly, in the embodiment examples in  FIGS. 12 to 13 , the one-part, elastically deformable transmission levers  29  are fixedly coupled at one end to the respective guide vane  21  and at an opposite end, via a spherical joint bearing  42 , to the control ring  27 . In a transition portion  43  between these two ends of the respective transmission lever  29 , the latter is resiliently elastically deformable so as to compensate a height offset or radial offset between the control ring  27  and the indirectly displaceable guide vanes  21  which varies during the circumferential displacement and axial displacement of the control ring  27 . 
     The embodiment example in  FIG. 14  differs from the embodiment example of  FIGS. 12 and 13  with respect to the specific construction of the transmission levers  28  and  29 . 
     While segments  31  and  32  of the transmission lever  28  are positioned substantially axially one behind the other in the embodiment example in  FIGS. 1 to 9 , these segments  31  and  32  of the transmission lever  28  are positioned substantially one above the other in radial direction in the embodiment example of  FIG. 14 . 
     A further difference between the embodiment example of  FIG. 14  and the embodiment example of  FIGS. 2 and 3  consists in the geometric contour of the one-part transmission levers  29 , which are resiliently elastically deformable in the transmission portion  43  between the two ends thereof, are therefore constructed so as to be relatively thin-walled in this transition portion  43  compared to the other portions thereof. 
     All of the embodiment examples have in common that a guide vane  21  of the guide vane ring  20  is drivable directly proceeding from a driveshaft  26 . The driveshaft  26  or the directly driven guide vane  21  is coupled with a control ring  27 . This coupling is preferably effected via a two-part swiveling lever  28  having preferably three spherical joint bearings. All of the rest of the guide vanes  21  of the guide vane ring  20  are indirectly drivable proceeding from the driveshaft  26  via the control ring  27 , these guide vanes  21  being coupled with the control ring  27  via further transmission levers  29 . Control ring  27  is radially supported coaxial to the rotational axis of a rotor, not shown, and can carry out an axial linear movement and a rotational movement in circumferential direction so as to be superimposed. The transmission levers  29  that serve to couple the indirectly adjustable guide vanes with the control ring  27  can be constructed of multiple parts or, alternatively, of one part just like the transmission lever  28  serving to connect the directly adjustable guide vane  21  to the control ring  27 . While the use of spherical joint bearings in the region of the transmission levers  28 ,  29  is preferred, hinge joints can also be used. 
     In  FIGS. 1 to 5 , transmission levers  28 ,  29  engage the radially outer ends of the vane roots outside of the housing structure  24 . In  FIGS. 6 and 7 , the transmission levers  28 ,  29  engage between the bearings  30  of the transmission levers  28 ,  29 . 
     With the guide vane adjusting device according to the invention, it is possible to adjust guide vanes of a guide vane ring in an optimal manner, specifically while ensuring a low total friction and a low torsional loading while preventing parasitic forces. The guide vane adjusting device of the present invention provides efficient kinematics for the displacement of the guide vanes of a guide vane ring with low loading of component parts so that high suction pressures can be used in a flow machine that utilizes the guide vane adjusting device. 
     Thus, while there have shown and described and pointed out fundamental novel features of the invention as applied to a preferred embodiment thereof, it will be understood that various omissions and substitutions and changes in the form and details of the devices illustrated, and in their operation, may be made by those skilled in the art without departing from the spirit of the invention. For example, it is expressly intended that all combinations of those elements and/or method steps which perform substantially the same function in substantially the same way to achieve the same results are within the scope of the invention. Moreover, it should be recognized that structures and/or elements and/or method steps shown and/or described in connection with any disclosed form or embodiment of the invention may be incorporated in any other disclosed or described or suggested form or embodiment as a general matter of design choice. It is the intention, therefore, to be limited only as indicated by the scope of the claims appended hereto.