Abstract:
In an actuating device for a turbine of an exhaust gas turbocharger, in particular for controlling the charging pressure of the exhaust gas turbocharger, wherein the exhaust gas turbocharger has an actuating shaft in the form of a first bolt element via which a valve element of the turbine is movable between a dosed position and an open position and which is non-rotatably connected to a connecting element that is pivotally coupled to a second bolt element by way of which the first bolt element can be pivoted about the axis of rotation by a translatory motion of an actuating element, both bolt elements are engaged on at least one first side of the connecting element via a single integral intermediate element for retaining the connecting element in engagement with the bolt elements.

Description:
[0001]    This is a Continuation-In-Part application of pending international patent application PCT/EP2012/005084 filed Dec. 08, 2012 and claiming the priority of German patent application 10 2011 121 391.4 filed Dec. 17, 2011. 
     
    
     BACKGROUND OF THE INVENTION 
       [0002]    The invention relates to an actuating device for a turbine of an exhaust gas turbocharger particularly for controlling the charging pressure of the exhaust gas turbocharger. 
         [0003]    Such an actuating device is disclosed for example in US 2003/0196435 A1. The actuating device which serves to control the charging pressure of the exhaust gas turbocharger comprises a first bolt element which is rotatable about an axis of rotation. A valve element, a so-called waste gate, of the turbine is movable between a closed position and at least one open position via the first bolt element. 
         [0004]    In the open position, the valve element opens a bypass duct, a so-called waste gate duct. The exhaust gas may bypass a turbine wheel of the turbine via the bypass duct so that the turbine wheel is not driven by the exhaust gas. The output of the turbine and thus the charging pressure of the exhaust gas turbo-charger may be controlled by opening and closing of the bypass duct. 
         [0005]    The first bolt element is non-rotatably joined to a connecting element, in this case to a connecting plate. The connecting element is articulatedly joined to an actuating element via a second bolt element. Here, the actuating element and the connecting element are joined rotatably about another axis of rotation relative to each other, with the axis of rotation and the other axis of rotation extending at least essentially parallel to each other. The actuating element is movable at least essentially vertically and translatorily to the axis of rotation of the first bolt element. 
         [0006]    By moving the actuating element translatorily, the first bolt element is rotated about its axis of rotation due to the connection of the actuating element with the connecting element as well as due to the connection of the connecting element with the first bolt element. This is accompanied by the movement of the valve element of the turbine. 
         [0007]    It was found that in particular due to wear as well as due to manufacturing-related tolerances some play between the connecting element and the bolt elements may develop which results in the generation of noises. 
         [0008]    It is therefore the object of the present invention to develop an actuating apparatus for a turbine of an exhaust gas turbocharger of the above mentioned type in such a manner that the turbine noises are at least reduced. 
       SUMMARY OF THE INVENTION 
       [0009]    In an actuating device for a turbine of an exhaust gas turbocharger, in particular for controlling the charging pressure of the exhaust gas turbocharger, wherein the exhaust gas turbocharger has an actuating shaft in the form of a first bolt element via which a valve element of the turbine is movable between a closed position and an open position and which is non-rotatably connected to a connecting element that is pivotally coupled to a second bolt element by way of which the first bolt element can be pivoted about the axis of rotation by a translatory motion of an actuating element, both bolt elements are engaged on at least one first side of the connecting element via a single integral intermediate element for retaining the connecting element in engagement with the bolt elements. 
         [0010]    With this arrangement, the above mentioned generation of noise can be kept particularly low or be prevented. The intermediate element which is common to the bolt elements provides for a compensation of in particular manufacturing-related and wear-related tolerances and clearances between the bolt elements and the connecting element, so that in particular rattling of the inventive actuating device is reliably prevented even over a long life. 
         [0011]    In addition, the integral intermediate element which is common to the bolt elements may be easily and thus quickly and cost efficiently installed and arranged between the bolt elements and the connecting element, in particular compared to respective, individual intermediate elements between the bolt elements and the connecting element. 
         [0012]    In another advantageous embodiment, at least one of the bolt elements, in particular the second bolt element is supported at a second side facing away from the first side of the connecting element at the connecting element via the integral intermediate element. This provides for a fixed and defined support so that any relative movement between the bolt elements and the connecting element and also noise resulting may be avoided even over a long life. 
         [0013]    When the integral intermediate element is attached at one of the bolt elements, in particular at the second bolt element, the number of parts and thus the costs of the inventive actuating apparatus will be kept low. Additional und separate fastening means are not necessary. In particular in combination with the two-sided support of the at least one bolt element the intermediate element may be firmly and reliably secured. 
         [0014]    In another embodiment of the invention, the at least one of the bolt elements is held at the connecting element by means of the intermediate element. Therefore, the intermediate element does not only fulfill the support function and thus the compensation of tolerances and clearances, respectively, but also the function of fastening the bolt element at the connecting element. By this integration of functions the number of parts, the costs and the weight of the inventive actuating device may be kept within a particularly narrow range. For fastening the intermediate element at the one bolt element and/or for holding the at least one bolt element at the connecting element, a locking engagement of the intermediate element with the one bolt element is preferably provided. This enables an easy, quick and cost efficient assembly. 
         [0015]    It is in particular possible to advantageously compensate for even relatively large tolerances and clearances if the intermediate element comprises at least one protrusion which is raised relative to at least a partial area adjoining the protrusion of the intermediate element and via which the intermediate element is supported resiliently at least at one of the bolt elements or at the connecting element, in particular. The protrusion facilitates in particular to clamp or to bias, respectively, the intermediate element with the at least one bolt element. Thereby, any relative movement and the resulting noise may be reliably prevented even for a long service life and operating periods with extreme temperature variations. 
         [0016]    The protrusion is advantageously formed by means of a coating, in particular a protective coating, of the intermediate element. Therefore, the intermediate element can be manufactured cost efficiently. It may further be provided to form the protrusion by at least a fiber and/or similar material build-up. 
         [0017]    In order to reliably compensate for clearances and tolerances, even with large temperature variations, the intermediate element is advantageously resiliently supported at the bolt elements. 
         [0018]    In another advantageous embodiment of the invention, the intermediate element comprises through-holes which are assigned to the respective bolt elements and which are penetrated by the associated bolt elements in a respective passage direction. Thus, the intermediate element may easily be mounted by inserting the bolt elements e. g. in the passage direction through the respective through-holes. 
         [0019]    In another embodiment, at least one of the through-holes is provided with an opening in the circumferential direction, via which the associated bolt element may be inserted under an angle, in particular vertically, to the passage direction into the through-hole. This is beneficial for a particularly easy, quick and cost efficient installation, which keeps the costs of the actuating apparatus and thus of the entire turbine particularly low. 
         [0020]    The intermediate element may be formed from a metallic material. Therefore, it has advantageous, in particular resilient, properties and can also at least essentially withstand large temperature variations without being damaged. The intermediate element is e. g. formed as a sheet metal strip. 
         [0021]    The intermediate element may also be formed from a synthetic material. This results in a particularly low weight of the intermediate element and thus of the actuating apparatus. 
         [0022]    Further advantages, features and details of the invention will become apparent from the following description of a preferred exemplary embodiment with reference to the accompanying drawings. The features and feature combinations as previously mentioned in the description as well as the features and feature combinations which will be mentioned in the following description of the figures and/or which are solely illustrated in the figures are not only applicable in the respective indicated combination but also in other combinations or isolated, without deviating from the scope of the invention. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0023]      FIG. 1  shows a schematic perspective view of an actuating apparatus for a turbine of an exhaust gas turbocharger, via which a bypass valve for a bypass duct of the turbine is adjustable and which exhibits a particularly advantageous noise behavior; 
           [0024]      FIG. 2  shows a schematic plan view of the actuating apparatus according to  FIG. 1 ; 
           [0025]      FIG. 3  shows a schematic side view of the actuating apparatus according to  FIGS. 1 and 2 ; 
           [0026]      FIG. 4  shows a schematic perspective view of an intermediate element of the actuating apparatus according to  FIGS. 1 to 3 ; 
           [0027]      FIG. 5  shows a schematic perspective view of another embodiment of the intermediate element according  FIG. 4 ; and 
           [0028]      FIG. 6  shows a schematic perspective view of another embodiment of the intermediate element according to  FIGS. 4 and 5 . 
       
    
    
     DESCRIPTION OF EXEMPLARY EMBODIMENTS 
       [0029]      FIGS. 1 to 3  show an actuating apparatus  10  for a turbine of an exhaust gas turbocharger. The exhaust gas turbocharger serves, for example, to charge a combustion engine of an automobile. The exhaust gas turbocharger comprises a compressor with a compressor wheel by means of which air to be supplied to the combustion engine is to be compressed. The compressor may be driven via the turbine of the exhaust gas turbocharger. 
         [0030]    For this purpose, the turbine comprises a turbine casing with a housing space in which a turbine wheel of the turbine is at least partially accommodated rotatably about an axis of rotation of the turbine wheel relative to the turbine casing. 
         [0031]    The turbine casing further comprises at least one supply duct via which exhaust gas of the combustion engine may be supplied to the turbine wheel. The exhaust gas can flow into the turbine wheel and drive it. The turbine wheel is connected non-rotatably with a shaft of the exhaust gas turbocharger, with which the compressor wheel, too, is non-rotatably connected. Thereby, the compressor wheel is driven by the turbine wheel. 
         [0032]    For controlling or regulating, respectively, of the charging pressure of the exhaust gas turbocharger which may be provided by the compressor, the turbine comprises at least one bypass duct. By means of the bypass duct, exhaust gas may be branched off upstream of the turbine wheel and be guided past the turbine wheel. In other words, the exhaust gas flowing through the bypass duct may bypass the turbine wheel without flowing into the turbine wheel and driving it. 
         [0033]    For controlling the quantity or mass, respectively, of the exhaust gas flowing through the bypass duct a valve element, a so-called waste gate valve, is provided which may be adjusted between a closed position and at least one open position. In the closed position, the bypass duct is fluidly blocked so that no exhaust gas may flow into the bypass duct and bypass the turbine wheel. 
         [0034]    In the at least one open position, the bypass duct is at least partially fluidly open so that exhaust gas may flow into the bypass duct and bypass the turbine wheel. 
         [0035]    Here, the valve element is adjustable via the actuating apparatus  10 . The actuating apparatus  10  comprises a lever arm bolt  12  which penetrates the turbine casing and is non-rotatably connected with the valve element. The lever arm bolt  12  is rotatable about a lever arm bolt axis of rotation  14  relative to the turbine casing. For providing high functional reliability, a bearing sleeve  16  is provided via which the lever arm bolt  12  is rotatably supported at the turbine casing. Moreover, a housing  18  is provided in which the lever arm bolt  12  is supported and which e. g. prevents a leakage of media such as exhaust gas, oil or the like from the turbine casing. 
         [0036]    The actuating apparatus  10  further comprises a connecting plate  20  with a first through-hole which is penetrated by the lever arm bolt  12 . In other words, the lever arm bolt  12  is installed in the first through-hole of the connecting plate  20 . Here, the connecting plate  20  is non-rotatably connected with the lever arm bolt  12 . 
         [0037]    The actuating apparatus  10  also comprises a connecting bolt  22  which penetrates a second through-hole of the connecting plate  20 . In other words, the connecting bolt  22  is installed in the second through-hole of the connecting plate  20 . The connecting bolt  22  is articulatedly connected with the connecting plate  20 . This means that the connecting bolt  22  is connected with the connecting plate  20  rotatably about a connecting bolt axis of rotation  24  relative to the connecting plate  20 . 
         [0038]    As can be seen in particular from  FIG. 3 , the lever arm bolt axis of rotation  14  and the connecting bolt axis of rotation  24  extend at least essentially parallel to each other. 
         [0039]    The connecting bolt  22  is non-rotatably connected with an actuating plate  26 . The actuating plate  26  is provided with a third through-hole in which the connecting bolt  22  is installed. 
         [0040]    Alternatively it may be provided that the connecting bolt  22  is non-rotatably connected with the connecting plate  20  and connected with the actuating plate  26  rotatably about the connecting bolt axis of rotation  24  relative to the actuating plate  26 . 
         [0041]    The actuating plate  26  is at least essentially normally and translatorily movable relative to the lever arm bolt axis of rotation  14  and the connecting bolt axis of rotation  24  and is articulatedly connected with the connecting plate  20  via the connecting bolt  22 . For a translatory movement or shifting, respectively, of the actuating plate  26 , it is at least indirectly connected with a pressure sensor of the exhaust gas turbocharger. 
         [0042]    When the valve element is e. g. in its closed position in which at least essentially the entirety of the exhaust gas flows into the turbine wheel driving it, and if the charging pressure of the exhaust gas turbocharger exceeds a predetermined threshold value, a diaphragm of the pressure sensor is caused to move. The movement of the diaphragm is at least indirectly transferred to the actuating plate  26  so that the actuating plate  26  is translatorily moved. Due to the described coupling of the actuating plate  26  with the lever arm bolt  12  as well as due to the coupling of the lever arm bolt  12  with the valve element, the translatory movement of the actuating plate  26  is transformed to a rotational movement of the lever arm bolt  12  about the lever arm bolt axis of rotation  14  and further to a swiveling motion of the valve element from its closed position to its open position. 
         [0043]    In order to avoid undesired relative movements of the connecting plate  20  relative to the lever arm bolt  12  and relative to the connecting bolt  22 , an intermediate element  28  illustrated in  FIG. 4  is provided. The intermediate element is integrally formed and arranged in the direction of the lever arm bolt axis of rotation  14  or of the connecting bolt axis of rotation  24 , respectively, between the connecting plate  20  and the lever arm bolt  12  and between the connecting plate  20  and the connecting bolt  22 . In other words, both the lever arm bolt  12  and the connecting bolt  22  are secured on the connecting plate  20  via the integral intermediate element  28 . This provides for the compensation of manufacturing-related and/or wear-related tolerances or clearances, respectively, or clearances between the connecting plate  20  and the lever arm bolt  12 , or the connecting bolt  22 , respectively, so that relative motion between the connecting plate  20  and the lever arm bolt  12  and the connecting bolt  22 , respectively, and the noise resulting therefrom may be avoided or minimized. 
         [0044]    As can be seen in particular from  FIG. 3 , the intermediate element  28  is arranged at a first side  30  of the connecting plate  20  between the lever arm bolt  12  and the connecting plate  20  and between the connecting bolt  22  and the connecting plate  20 . In addition, the intermediate element  28  is also arranged at a second side  32  of the connecting plate  20  facing away from the first side  30  between the connecting plate  20  and the connecting bolt  22 . Thereby, a particularly strong and advantageous connection of the connecting bolt  22  with the connecting plate  20  is implemented. In other words, the connecting plate  20  is secured at the connecting bolt  22  by means of the intermediate element  28  and vice versa, respectively. 
         [0045]    The integral nature of the intermediate element  28  enables a quick and cost efficient assembly. Further, clearance and tolerance compensation is effected at all connecting points of the actuating apparatus  10  which may be prone to clearances by means of the only one integral intermediate element  28 . This also contributes to low wear of the actuating apparatus  10 . The intermediate element  28  also enables advantageously to avoid or minimize the generation of noise upon an excitation of the actuating apparatus  10 . 
         [0046]    As can be seen in particular from  FIG. 4 , the intermediate element  28  comprises a first through-hole  34  in which the connecting bolt  22  is received at the second side  32 . Starting from the first through-hole  34 , the intermediate element  28  which in the present case is formed as a sheet metal strip extends around the connecting plate  20  to the first side  30 , where the intermediate element  28  comprises a second through-hole  36  for receiving the connecting bolt  22  at the first side  30 . 
         [0047]    The intermediate element  28  further comprises a third through-hole  38  in which the lever arm bolt  12  is installed at the first side  30 . 
         [0048]    The through-holes  34 ,  36 ,  38  each have a passage direction, in which they are penetrated by the connecting bolt  22  or the lever arm bolt  12 , respectively. 
         [0049]    While the second through-hole  36  is completely closed in the circumferential direction the through-holes  34 ,  38  comprise respective openings in the circumferential direction. It is e. g. possible to insert the lever arm bolt  12  into the third through-hole  38  vertically to its passage direction via the opening of the third through-hole  38 . In other words, the intermediate element  28  may be mounted vertically to the passage direction of the third through-hole  38  onto the lever arm bolt  12 . 
         [0050]    This may apply analogously for the first through-hole  34  into which connecting bolt  22  may be inserted vertically to the passage direction of the first through-hole  34 . On the other hand, this means that the intermediate element  28  may be mounted vertically to the passage direction of the first through-hole  34  onto the connecting bolt  22 . 
         [0051]    The through-holes  34 ,  38  which are open in the circumferential direction are defined by respective arms  40  of the intermediate element  28 , which may encompass the connecting bolt or the lever arm bolt  12 , respectively, in particular resiliently. Thereby, the intermediate element  28  is reliably secured both at the connecting bolt  22  and the lever arm bolt  12 . 
         [0052]    The first through-hole  34  of the intermediate elements  28  according to  FIGS. 5 and 6  is also completely closed in the circumferential direction so that the connecting bolt  22  may be inserted into the through-holes  34 ,  36  in the passage direction. 
         [0053]    The intermediate element  28  also comprises first protrusions  42  and second protrusions  44 . The protrusions  42 ,  44  are raised relative to the partial areas adjoining the protrusions  42 ,  44  of the relatively thin-walled intermediate element  28 . The first protrusions  42  are assigned to the connecting bolt  22 , while the second protrusions  44  are assigned to the lever arm bolt  12 . The intermediate element  28  is supported on the first side  30  at the connecting plate  20  via the first protrusions  42 . Correspondingly, the intermediate element  28  is supported on the first side  30  at the connecting plate  20  via the second protrusions  44 . Because the intermediate element  28  is also supported at the connecting bolt  22  and at the lever arm bolt  12  the intermediate element  28  may be particularly firmly clamped between the connecting plate  20  and the lever arm bolt  12 , and the connecting bolt  22 , respectively, by means of the protrusions  42 ,  44  so that the connecting plate  20  is positively and advantageously engaged with the lever arm bolt  12  and the connecting bolt  22 . This allows the efficient and effective compensation of clearances and/or tolerances. 
         [0054]    Alternatively or additionally the intermediate element  28  may also be supported via at least one corresponding protrusion at the connecting bolt  22  and/or via at least one corresponding protrusion at the lever arm bolt  12 . 
         [0055]    The protrusions  42 ,  44  are formed e. g. by stamping or the like of the sheet metal strip. The protrusions  42 ,  44  may, however, be also formed by a material build-up, e. g. by means of a coating, at least a fiber or a similar material build-up of the intermediate element  28 . 
         [0056]      FIGS. 5 and 6  show further embodiments of the intermediate element  28 , which are adapted to specified installation conditions or installation conditions which may be predetermined, respectively.