Abstract:
A clutch shaft for a camshaft controller having at each of two ends ( 30, 31 ) thereof a rotating joint which equalizes the angle between the axes. An actuator for controlling a camshaft adjustment transmission includes a clutch shaft for controlling the camshaft adjustment transmission to the actuator via a first rotating joint which equalizes the angle between the axes which is coupled in a region of the actuator which faces away from the adjustment transmission.

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS 
       [0001]    The present application claims priority under 35 U.S.C. §119 to German Patent Application No. 10 2011 103 495.5 (filed on Jun. 3, 2011), which is hereby incorporated by reference in its respective entirety. 
       FIELD OF THE INVENTION 
       [0002]    The present invention relates to a clutch shaft for a camshaft controller, an actuator for controlling a camshaft adjustment transmission, a camshaft adjustment transmission which is also referred to hereinbelow as an “adjustment transmission,” and a camshaft adjustment device for an internal combustion engine. 
       BACKGROUND OF THE INVENTION 
       [0003]    German Patent Publications DE 10 2004 041 751 A1, DE 10 2007 049 072 A1 and DE 102 48 351 A1 disclose various clutches for equalizing an eccentricity (axial offset) between an axis of an actuating shaft of an actuator and an axis of an adjustment transmission. These clutches exert, in the case of corresponding radial axial offset of the corresponding shafts, forces of inertia on these shafts and their bearings. In the case of Oldham clutches, the large axial installation space requirement is also disadvantageous. 
       SUMMARY OF THE INVENTION 
       [0004]    An object of the present invention is to provide a dutch shaft for a camshaft controller with which forces of inertia on these shafts and their bearings can be reduced. It is furthermore an object of the invention to provide an actuator, a camshaft adjustment transmission and a camshaft adjustment device structured to facilitate this advantage. 
         [0005]    This object is achieved with a clutch shaft which includes at least one of the following: 
         [0006]    This object is achieved with a clutch shaft which includes at least one of the following: 
         [0007]    This object is achieve with a clutch shaft which includes at least one of the following: 
         [0008]    In accordance with the invention, the clutch shaft for a camshaft controller is developed further in that the clutch shaft has at each of its two ends, in each case a clutch component, for in each case a rotating joint which equalizes the angle between the axes. Due to the fact that the clutch shaft in accordance with the invention has a clutch component at each of its two ends, it is possible to equalize an axial offset without a bringing about or enlargement of an axial angle between the actuator and the adjustment transmission having to be accepted as a result of this measure. 
         [0009]    By dividing the axial offset adjustment between two clutches, the designer is given a greater degree of freedom which to exploit a reduction in the axial angle for the introduction of force into the actuator or into the adjustment transmission. By reducing the axial angle for the introduction of force into the actuator or into the adjustment transmission, a rotational symmetry of the force transmission is improved and a magnitude of the disadvantageous forces of inertia is reduced. The clutch shaft can, but need not be, in one-piece. 
         [0010]    A (total) axial length of the clutch shaft can be greater than w % of a maximum diameter of the larger clutch component, wherein w % is at least 130%, in particular at least 150%. The clutch shaft can be tapered between its two ends across more than w % of its (total) axial length, wherein w % is at least 30%, in particular at least 60%. The clutch shaft can comprise on at least one of its two face sides a cylinder-symmetrical, convex formation which is arranged concentrically with respect to the main longitudinal axis of the clutch shaft. The clutch shaft can comprise a flange for a bearing. 
         [0011]    The first rotating joint which equalizes the angle between the axes can comprise a fastening bolt or a component of a denture clutch, a claw clutch, a plug clutch, a driver clutch, a radial gearwheel clutch, a disc gearwheel clutch, a flexible disc, a bellows clutch, an elastomer clutch, a helix clutch, a spring clutch, a spring disc clutch, a fixed link clutch, a balancing clutch, a cardan transmission or a homokinetic joint. Independently of this, the second rotating joint which equalizes the angle between the axes can comprise a fastening bolt or a component of a denture clutch, a claw clutch, a plug clutch, a driver clutch, a radial gearwheel clutch, a disc gearwheel clutch, a flexible disc, a bellows clutch, an elastomer clutch, a helix clutch, a spring clutch, a spring disc clutch, a fixed link clutch, a balancing clutch, a cardan transmission or a homokinetic joint. The denture clutch component can comprise an arcuate denture clutch. The denture clutch component can have a spherical or spherical portion-shaped basic shape on which the teeth of the denture clutch component are arranged. 
         [0012]    In accordance with the invention, the actuator is developed further in that a clutch shaft for controlling the camshaft adjustment transmission is coupled to the actuator by way of a first rotating joint which equalizes the angle between the axes in a region of the actuator which faces away from the adjustment transmission. As a result of this, in the case of an unchanged distance between actuator and camshaft adjustment transmission, the distance between the location of the connection, which can be angled, to the rotor and the camshaft adjustment transmission can be increased, as a result of which a reduction in the axial angle for the introduction of force into the adjustment transmission is achieved, a rotational symmetry of the transmission of force is improved and a magnitude of the disadvantageous forces of inertia is reduced. 
         [0013]    The clutch shaft can extend across more than 50% of a (total) axial length of a rotor of the actuator. The clutch shaft can be arranged rotatably in the pitch direction in the actuator on each circumferential angle, wherein a pitch angle of the clutch shaft with respect to an axis of the actuator can be up to at least 1°, in particular up to at least 2°, particularly preferably up to at least 3°. The clutch shaft can be arranged axially displaceably in the rotor. 
         [0014]    The actuator can comprise an axial bearing component for pretensioning the clutch shaft in the direction of the main longitudinal axis of the clutch shaft. The actuator can comprise a clutch shaft in accordance with the invention. 
         [0015]    The first rotating joint which equalizes the angle between the axes can comprise, for coupling to the rotor, a fastening bolt or a component of a denture clutch, a claw clutch, a plug clutch, a driver clutch, a radial gearwheel clutch, a disc gearwheel clutch, a flexible disc, a bellows clutch, an elastomer clutch, a helix clutch, a spring clutch, a spring disc clutch, a fixed link clutch, a balancing clutch, a cardan transmission or a homokinetic joint. 
         [0016]    In accordance with the invention, the camshaft adjustment transmission is further developed in that an inner or outer toothing of a transmission drive gearwheel of the camshaft adjustment transmission is formed or is suitable for the engagement of the denture clutch component of a clutch shaft or that the camshaft adjustment transmission comprises a clutch shaft. 
         [0017]    The denture clutch component of the clutch shaft can form a floating transmission drive gearwheel of the camshaft adjustment transmission. 
         [0018]    In accordance with the invention, the camshaft adjustment device is developed further in that it comprises an actuator and/or a cam adjustment transmission. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0019]    The invention is described below by means of exemplary embodiments illustrated in the drawings in which show: 
           [0020]      FIG. 1  schematically illustrates a partial sectional side view of a camshaft controller in accordance with a first embodiment of the invention. 
           [0021]      FIG. 2  schematically illustrates a perspective side cross-sectional view of the first embodiment of the camshaft controller in accordance with the first embodiment of the invention. 
           [0022]      FIG. 3  schematically illustrates, in a side view, a basic concept of the axial offset equalization in accordance with the first embodiment of the invention. 
           [0023]      FIG. 4  schematically illustrates, in a side view, a basic concept of the axial offset equalization in accordance with a second embodiment of the invention. 
           [0024]      FIG. 5  schematically illustrates a partial sectional side view of a camshaft controller with a clutch shaft in accordance with a third embodiment of the invention. 
           [0025]      FIG. 6  schematically illustrates a detailed side cross-sectional view of the camshaft controller in accordance with the third embodiment of the invention. 
           [0026]      FIG. 7  schematically illustrates a perspective view of an open camshaft adjustment transmission with a floating transmission drive gearwheel. 
       
    
    
     DETAILED DESCRIPTION OF EMBODIMENTS 
       [0027]    The same reference numbers are used in each case for corresponding components in the figures. Explanations relating to reference numbers therefore apply across the figures unless otherwise apparent from the context. 
         [0028]    Camshaft controller  10  shown in  FIGS. 1 and 2  comprises a servomotor  12  and an adjustment transmission  32 . Servomotor  12  can be, for example, an electric machine (electric motor), a hydraulic drive or a pneumatic drive. Servomotor  12  includes a rotor  14  which is mounted in two rotor bearings  16 . Rotor  14  includes a hollow shalt  18  which is surrounded by a radial shaft sealing washer  20  which helps to seal off oil-filled camshaft chamber  22  from parts of servomotor  12 . Parts  26 ,  32 , on the camshaft side, of camshaft controller  10  are typically located under engine oil  24 . A clutch shaft  26  is guided through hollow shaft  18  and is fastened to rotor  14  on that side of rotor  14  which faces away from adjustment transmission  32 . Clutch shaft  26  can extend over more than 50% of a (total) axial length of a rotor  14 . 
         [0029]    At an end  30  of the clutch shaft  26  on the servomotor side, clutch shaft  26  is articulated at rotor  14  by way of a fastening bolt  34  for a transmission of torque to adjustment transmission  32 . Clutch shaft  26  has at its end  30  on the servomotor side a passage  25  for a fastening bolt  34 . Fastening bolt  34  is mounted in opposing holes  36  in the wall of hollow shaft  18 . In the region of passage  25  for fastening bolt  34 , clutch shaft  26  can have a spindle-shaped or spherical thickening  38 , the outer diameter of which is only slightly smaller than inner diameter  40  of hollow shaft  18 . As a result of this, it is achieved that clutch shaft  26  (independently of its gyrating motion) is fastened in hollow shaft  18  such that, at the location of fastening bolt  34 , a main longitudinal axis  27  of clutch shaft  26  has a common point of intersection  42  with the main longitudinal axis  19  of hollow shaft  18 . 
         [0030]    Fastening bolt  34  is rotatably mounted in hollow shaft  18  about its main longitudinal axis  35 . As illustrated in  FIG. 2 , such a rotation is a rolling motion  44  of fastening bolt  34 . Moreover, fastening bolt  34  is mounted in hollow shaft  18  with so much play that it can be tilted with respect to an axis  37  of holes  36 . Such a tilting  48  is a pitch motion of fastening bolt  34 . Due to the fact that fastening bolt  34  can perform both a rolling motion  44  and a pitch motion  48  in hollow shaft  18 , clutch shaft  26  can (relative to point of intersection  42  of main longitudinal axes  19 ,  27 ) be tilted in any radial direction, i.e., can gyrate. In order to support clutch shaft  26  in the axial direction or pretension it against adjustment transmission  32 , clutch shaft  26  can include on at least one of its two face sides  30 ,  31  a cylinder-symmetrical, convex formation  28  which is arranged concentrically with respect to main longitudinal axis  27  of clutch shaft  26 . 
         [0031]    As illustrated in  FIG. 3 , a (disc-shaped) securing flange  50  can be clamped between elastomer discs  52  which are arranged concentrically on rotor side  54 . As a result of this arrangement, clutch shaft  26  can, during rotation of rotor  14 , perform an even or smooth gyrating motion. Instead of a securing flange  50 , several projections can also be fixed or formed on clutch shaft  26 , which projections point, for example, in multiple (e.g., 3, 4 or 5) circumferential directions. On other side  31  of clutch shaft  26 , a bevel gear  60  of clutch shaft  26  engages in a bevel gear  72  of adjustment transmission  32 . As a result of the mutual self-centering of bevel gears  60 ,  72  and the pressure of spring-supported bevel support  62 , the teeth of both bevel gears  60 ,  72  remain in undetectable engagement despite the axial angle  64  between clutch shaft  26  and adjustment transmission  32 . 
         [0032]    Dashed lines indicate ridges of the interengaging teeth of bevel gears  60 ,  72 .  FIG. 3  also illustrates that adequate play  66  can be provided between clutch shaft  26  and hollow shaft  18  so that enough free space is left for clutch shaft  26  for the necessary gyrating motion. To this end, clutch shaft  26  can be tapered between its two ends  30 ,  31  across more than w % of its axial length  39 , wherein w % is at least 30%, in particular at least 60%. In the case of corresponding axial offset  79 , the shown angle arrangement can not only be apparent in a side view, rather also from the view of each different circumferential angle of the main longitudinal axis of rotor  14 . 
         [0033]    As illustrated in  FIG. 4 , clutch shaft  26  can also be fastened rigidly to rotor  14  if it has sufficient flexibility along with simultaneously adequate torsional strength. In the case of a circular or ring-shaped cross-section of clutch shaft  26 , an increase in flexibility typically equally involves an increase in torsional strength. Depending on the application, it can, however, also be the case that (for example, as a result of a speed reduction) a twisting of flexible clutch shaft  26  is not disruptive. Or an attempt can be made by selection of a material with a suitable Poisson&#39;s ratio, by selecting an anistropic material or by an anisotropic structure of the clutch shaft to adjust the ratio of flexural stiffness to torsional strength to concrete application requirements. In the case of corresponding axial offset  79 , the shown angle arrangement can not only be produced in a side view, but also from the perspective of any other circumferential angle of the main longitudinal axis of rotor  14 . 
         [0034]    As illustrated in  FIGS. 5 and 6 , clutch shaft  26  has, on the servomotor side, an arcuate denture clutch component  58 . Arcuate toothing enables an angling of clutch shaft  26  with respect to a main longitudinal axis  15  of rotor  14  and hollow shaft  18 . Independently of this, inner toothing  59  of hollow shaft  18  enables an axial positional adjustment of clutch shaft  26  along main longitudinal axis  19  of hollow shaft  18 . Clutch shaft  26  illustrated  FIGS. 5 and 6  also comprises on the side of adjustment transmission  32  an arcuate denture clutch component  60  which engages in an inner crown gear of a transmission drive gearwheel  72  of adjustment transmission  32 . Arcuate denture clutch component  60  has here a larger diameter  69  because transmission drive gearwheel  72  is located at a point at which, during assembly, a fastening screw for adjustment transmission  32  with chain wheel  74  at which camshaft  76  is to be guided through. 
         [0035]    As already explained in relation to  FIG. 3 , clutch shaft  26  can also be pressed or otherwise biased by way of spring force in the direction of adjustment transmission  32  in the case of the third embodiment. End  31 , which points towards camshaft  76 , of clutch shaft  26  can be supported by a self-aligning bearing in adjustment transmission  32  (for example, on an intermediate gearwheel) or alternatively against camshaft  76 . End  31  of clutch shaft  26  can be mounted on a ball bearing  78  which has a spherical outer ring  80  such that it can be slightly angled in the case of axial offset  79  with respect to main axis  33  of adjustment transmission  32 . Clutch shaft  26  can have a flange  81  on which ball bearing  78  is fastened. Ball bearing  78  can lie within a crown gear  72 . It can be supported on a pin of camshaft  76 . 
         [0036]      FIG. 7  illustrates a perspective view of an open adjustment transmission  32  with transmission drive gearwheel  72 . Transmission drive gearwheel  72  is embodied here as a floating gearwheel and has an inner toothing and an outer toothing. Transmission drive gearwheel  72  serves to drive an adjustment shaft of adjustment transmission  32  via a speed reduction with intermediate gearwheels  84 . Flanges  82  on transmission drive gearwheel  72  and on intermediate gearwheels  84  retain transmission drive gearwheel  72  at the axial position between intermediate gearwheels  84 . In relation to the direction perpendicular to the axial connection of intermediate gearwheels  84 , transmission drive gearwheel  72  is retained by guiding wheels  86 . Independently of this, transmission drive gearwheel  72  should also be adequately fixed or mounted in the axial direction. This can be achieved, for example, by sliding bearing surfaces or by a ball bearing. 
         [0037]    In accordance with embodiments of the present invention, a clutch shaft  26 , an actuator  12 , a camshaft adjustment transmission  32  and a camshaft controller  10  are provided, with which radial forces between the clutch and the transmission input shaft can be reduced or prevented. This applies in particular in combination with a floatingly mounted transmission input shaft (transmission drive gearwheel  72 ). Independently of this, the space-saving design enables a reduction in the axial installation space requirement for camshaft controller  10 . Installation space which can be saved for the clutch by servomotor  12  with adjustment transmission  32  enables the use of a lower cost adjustment transmission  32  or a lower cost servomotor  12 . 
         [0038]    Although embodiments have been described herein, it should be understood that numerous other modifications and embodiments can be devised by those skilled in the art that will fall within the spirit and scope of the principles of this disclosure. More particularly, various variations and modifications are possible in the component parts and/or arrangements of the subject combination arrangement within the scope of the disclosure, the drawings and the appended claims. In addition to variations and modifications in the component parts and/or arrangements, alternative uses will also be apparent to those skilled in the art.