Abstract:
A camshaft adjuster with a stator and a rotor having several radially protruding vanes, which run against stops in order to limit the hydraulically controlled adjustment motion is provided. The stops ( 9, 9′, 9   a - 9   o ) are provided on a lateral cover plate ( 10 ) or a side wall or a disc-shaped or circular stop element ( 12 ) provided inside the cover plate or the side wall.

Description:
FIELD OF THE INVENTION  
       [0001]     The invention relates to a camshaft adjuster having a stator and a rotor with several radially protruding vanes moving against stops in order to limit the hydraulically controlled adjustment motion.  
       BACKGROUND  
       [0002]     It is commonly known that a camshaft adjuster can be used to adjust the relative angle, fixed in stationary operation, of the camshaft to the drive shaft driving it, with the shafts being coupled to one another via a control chain or a control belt, in order to be able to vary the timing of the intake and/or exhaust valves operated by the camshaft. Known camshaft adjusters operating according to the vane-cell principle or the rotating vane principle, are provided with a rotor having several protruding vanes, which may be provided in one piece with the rotor, or which may be arranged using a radially outward spring force, and an exterior stator. At the stator, which usually comprises a sintered component, stops protruding radially inwards are formed, which limit the adjustment motion of the rotor in the one circumferential direction or the other one, by the vanes moving against said stops. The vanes contact the stator with the edges of their faces, so that a chamber is formed between one side of the vane and the adjacent side of a stop each, into which fluid, usually motor oil, is transported via a valve allocated at the camshaft adjuster, serving to adjust the rotor in reference to the stator. Here, in the known camshaft adjusters, the stator has a double function, namely, on the one hand to separate the fluid chambers and, on the other hand, to determine the adjustment angle.  
         [0003]     Different, type-specific adjustment angles are necessary for the various motor types depending on the embodiment of the camshaft and/or the valves etc. This means that a type-specific stator is required for each application, according to which the stator is provided with the stops defined for maximum adjustment angles. This particularly increases the expenses for the production of the stator, because each stator type is to be produced separately, e.g., by way of sheet metal forming or aluminum extrusion molding or by way of cutting, or requires a special type of sintering, and the storage is also very expensive, because a multitude of various types must be kept at hand.  
       SUMMARY  
       [0004]     The invention is based on the objective of providing a camshaft adjuster, which is constructed in an easier fashion, particularly regarding its production technology.  
         [0005]     This objective is attained according to the invention in a camshaft adjuster of the type mentioned at the outset such that the stops are provided at the lateral cover plate or a side wall or a disc shaped or ring shaped stop element arranged inside the cover plate or the side wall.  
         [0006]     In the camshaft adjuster according to the invention the stops limiting the adjustment motion are, in contrast to the one of prior art, no longer provided at the stator, yet rather either at the lateral cover plate itself, which is encapsulated towards the outside by the camshaft adjuster, and at which, for example, a sprocket or a locking device, etc. is arranged. The stops may also be provided at the laterally limiting side wall, which, for example, is part of a third part, onto which the adjuster is placed. As an alternative to positioning the stops at the cover plate/the side wall, there is the possibility to integrate a disc-shaped or ring-shaped stop element inside the cover plate, on which the stops are provided. The stator itself merely has the function to separate the fluid chambers, i.e. there are still protrusion provided, now considerably narrower ones, which still protrude radially inward, however, they no longer act in a stop function. This means that the stator may de facto provided as a standard component, because the separation of the oil chambers is identical for many types of adjusters. The individualization regarding the adjustment angles occurs solely via the cover plate/the side wall provided with the stops and/or via the stop element provided with stops, so that merely those parts need to be manufactured individually. These components usually comprise simple metal pieces, in particular sheet metal parts, which are easy to produce with respect to the stops to be provided here. For reasons of simplification, the entire description following merely mentions cover plates, however the embodiments similarly apply to the arrangement of stops on a side wall.  
         [0007]     Therefore, since the stator can be standardized for many different types, an essentially simpler structure of the adjuster itself results, and the production costs can be reduced as well. Additionally, since the stops at the sintered stator are no longer provided, rather merely relatively small protrusions limiting the fluid chambers, a reduction in weight and structural space results.  
         [0008]     As described above, the cover plate and/or the stop element beneficially comprise a relatively thin-walled metal component. Therefore, it is beneficial if the stops are made from the metal cover plate or the metal cover element by way of forming. In this context a multitude of different forming techniques can be used that are known in the field of sheet metal formation.  
         [0009]     According to a first embodiment of the invention, each stop may be provided in the form of a closed or open impression. In this context, impression defines a deformation-related parts-formation, which results in the respective part being profiled in order to form stops. Usually a die is used here, which forms the deformation pattern. In this embodiment according to the invention the stops are formed by way of deformation from the metal sections protruding out from the level of the cover plate or the stop element. Depending on the type of deformation, they may be closed, i.e. the metal sections were merely pushed outward, the cover plate overall however remains closed. Alternatively, an open impression may be realized as well, as for example by way of completely punching through. In this case it is also possible to provide the open impression with an internal thread, which allows the screwing in of a bolt, which simultaneously serves to provide a means for fastening the cover to the adjustment housing during the deformation of the cover, for example. This means, here, the impression has a double function. In the event that the impression is formed in an area, which does not allow a threaded connection of the cover plate to the adjustment housing, the integration of the interior thread offers the chance to seal the cover plate by way of screwing in the screw at this location. In the case, an open impression is realized without any interior thread at a cover plate, an appropriate sealant were certainly to be inserted into the open impression in order to prevent the fluid to drain through the cover plate. The cover plate is certainly not necessary when the open impression is provided at a stop element integrated inside the cover plate, after the adjuster seal has been applied over the mounted cover plate.  
         [0010]     In general, a slight radius forms during the impression at the area of the transition of the impression to the deformed body, which acts like a ramp when the vane runs against the stop, sometimes resulting in the vane becoming jammed since the vane can contact the ramp-like radius regardless of its relatively small size. In order to counteract that, an advantageous further development of the invention provides for the impression to be upset in the area of its free end in order to widen it. This means that at the opposite, free end of the impression, a radial enlargement is formed by way of upsetting, which serves as the exterior stop shoulder and prevents any buffing of the interior ramp-like radius. Alternatively it is possible to slightly reverse the entire impression by way of deformation in the opposite direction of the impression so that the radius formed is returned to the level of the component.  
         [0011]     Alternatively to the formation of an impression it is also possible to realize the stops by way of flap-like bends, for which an interrupted, for example U-shaped cut is inserted, in order to bend the flap formed out of the level of the component. Naturally, the opening must be resealed when it is mounted to the cover plate; this is not necessary in a flap formation at a stop element.  
         [0012]     As a further alternative to the deformation of the cover plate or the stop element for the formation of stops made from the component itself, the invention provides for the stops also to be formed by way of stop pieces mounted to a cover plate or a stop element. Here, rivets, particularly pressed ones, or pins, inserted into the respective openings are possible, as well as pins or bends or the like welded, soldered, or glued to the cover plate or the element. Any element or any other object, which can form a stop, is suitable. Here, screws screwed into the cover plate or the element are also included, which can be screwed into the openings, provided with the appropriate interior threads, or which can be screwed to the cover plate or the element, preferably to interior threads mounted at their outside.  
         [0013]     It is generally understood that in the respective case, if necessary, seals in the appropriate form can be used, e.g., gaskets, sealants, glues etc. Additionally, there is certainly the possibility to provide to the two opposite adjuster sides, at which a cover plate is to be provided, with a cover plate provided with stops, so that the rotor runs on both sides against stops, so to speak, and of course the appropriate stop elements may also be integrated here. 
     
    
     BRIEF DESCRIPTION OF THE DRAWING  
       [0014]      FIG. 1  is a schematic view of a component of a camshaft adjuster with a partial view of the rotor and the stator,  
         [0015]      FIG. 2  is a perspective partial view of a cover plate provided with stops in one half of the figure, and/or of a stop element according to the invention in the other half of the figure,  
         [0016]      FIG. 3  is a partial section through a cover plate or a stop element, in order to show a first embodiment of a stop formed by way of an impression,  
         [0017]      FIG. 4  is a sectional view of a second stop embodiment,  
         [0018]      FIG. 5  is a sectional view of a third stop embodiment,  
         [0019]      FIG. 6  is a sectional view of a fourth stop embodiment,  
         [0020]      FIG. 7  is a sectional view of a fifth stop embodiment,  
         [0021]      FIG. 8  is a sectional view of a sixth stop embodiment having an internal thread,  
         [0022]      FIG. 9  is a sectional view of a seventh stop embodiment having an internal thread,  
         [0023]      FIG. 10  is a sectional view of an eighth stop embodiment in the form of a flap,  
         [0024]      FIG. 11  is a sectional view of a ninth stop embodiment in the form of a pressed-in pin,  
         [0025]      FIG. 12  is a sectional view of a tenth stop embodiment in the form of a pressed-in rivet,  
         [0026]      FIG. 13  is a sectional view of an eleventh stop embodiment in the form of a welded-on pin,  
         [0027]      FIG. 14  is a sectional view of a twelfth stop embodiment in the form of a welded-on or glued-on bent stop,  
         [0028]      FIG. 15  is a sectional view of a thirteenth stop embodiment in the shape of a screwed in bolt,  
         [0029]      FIG. 16  is a sectional view of a fourteenth stop embodiment in the shape of a bolt screwed into an internal screw component  
         [0030]      FIG. 17  is a sectional view of a fifteenth stop embodiment in the shape of a bolt screwed into a third object, and  
         [0031]      FIG. 18  is a representation according to  FIG. 17 . 
     
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS  
       [0032]      FIG. 1  shows a sectional view of a camshaft adjuster  1  according to the invention, in which, here, only the stator  2  and the rotor  3  are shown. At the stator  2 , which may represent for example a sintered component (steel and aluminum components are also possible), protrusions  4 , are provided radially protruding inwards, forming the walls limiting two chambers  5 ,  6 , which are separated by radially outwardly protruding vane  7  from a rotor, which vane closely contacts the interior wall  8  of the stator. Fluid can be inserted into and/or withdrawn from these chambers for adjusting the rotor in reference to the stator, allowing a hydraulic rotor movement as indicated by the double arrows.  
         [0033]     As described, it is the sole function of the protrusions  4  to separate the chambers. In order to limit the bilateral adjustment movement indicated by the double arrow A, stops  9  are provided, which according to the invention are provided at a cover plate or a stop element, not shown in greater detail in  FIG. 1 . The stator  2  also represents a standardized component, its design only depending on the number of chambers desired, i.e., the appropriate number of protrusions  4  are to be provided depending on the number of chambers. However, the structure is identical for many types of adjusters, so that such a stator can be used for a multitude of various types.  
         [0034]     As shown in  FIG. 1 , due to the placement of the stops at the cover plate or the stop element, the position of the stops can be varied very easily depending on the type of application. While the stops  9  of the position shown in solid lines in  FIG. 1  allow a relatively small adjustment angle, the stops  9 ′ shown dashed in  FIG. 1 , permit a considerably larger adjustment angle. For this purpose, only the cover plate, embodied appropriately, or the stop element, embodied appropriately, are to be integrated with the adjuster, thus, the individualization of the types regarding the limits of the adjustment angles can be performed very easily and in a cost effective manner.  
         [0035]      FIG. 2  shows, in the form of a perspective partial representation, on the one hand, a section of a cover plate  10  according to the invention, at which in the example shown several stops  9  are provided at the inside, axially protruding towards the rotor axis. In the example shown, the stops have an essentially rectangular shape. However, the shape of the stops is not limited to this, though. Any shape is possible, e.g., round, oval, bent, etc. Further, several openings  11  are shown, by which the cover plate  10  is mounted to the adjuster housing.  
         [0036]     In the right half in  FIG. 2 , a stop element  12  according to the invention is partially shown, which is ring-shaped in this exemplary embodiment. The respective stops  9  are formed here, too, and it can also be held to the housing via respective openings  11  after the positioning of the cover plate to the stop element  12 . When such a stop element  12  is integrated, the cover plate itself is not being deformed.  
         [0037]     The following figures show a multitude of various stop forms, each of which shows a cross-section through the stop, which may be provided with an arbitrary shape as described.  
         [0038]      FIG. 3  shows a first stop  9   a  in the form of a closed impression. Thus, the stop  9   a  is expressed from the cover plate or the stop element by way of a suitable deformation. This impression shows a small radius  13  at the pedestal, which may potentially lead to a jamming of the vane, which can buff onto said radius. In order to counteract that,  FIG. 4  shows another stop  9   b , which is upset to some extent at its free end so that a circular shoulder  14  is formed, which is slightly larger than the radial bulge at the pedestal, so that the described buffing and jamming is avoided.  
         [0039]     Another alternative to avoid it is shown in  FIG. 5 . The stop  9   c  shown here is slightly set back in the direction of the impression, i.e., the stop  9   c  has been pressed back into the level of the cover plate or the element after the impression.  
         [0040]      FIG. 6  shows another stop  9   d , which is provided in the form of an open impression, for example formed by a punching process. Here too, a small radius  13  might result, which can cause jamming. In order to counteract that here as well,  FIG. 7  shows a stop  9   e , which, similarly to the stop  9   c , is slightly set back.  
         [0041]      FIG. 8  shows a stop  9   f , formed in this case by way of a round through punching, and provided with an internal thread  15 , which allows the screwing in either of a mounting screw or a sealing screw, if necessary. This stop may also be set back in order to remove the radius  13 , see stop  9   g  in  FIG. 9 .  
         [0042]     Finally,  FIG. 10  shows another stop  9   h  formed by deformation. This one is made in the form of a flap, which is pressed inwardly out of the level of the cover plate or the element after said element first had been cut into.  
         [0043]     While  FIGS. 3-10  show stops, which were formed by an immediate deformation of the cover plate or the stop element itself,  FIGS. 11 through 18  show embodiments of stops using third objects.  
         [0044]     Thus,  FIG. 11  shows a stop  9   i , formed by way of a pin, which is pressed into a corresponding opening  16  at the cover plate or the element.  FIG. 12  shows a stop  9   j  instead of the pin, formed by a rivet, which is also pressed into an appropriate opening  16 .  
         [0045]     However,  FIG. 13  shows a stop  9   k , formed by a pin mounted by a welded, soldered, or glued connection  17 .  
         [0046]     While the pin shown in  FIG. 13  is mounted at the inside of the cover plate or the element,  FIG. 14  shows a stop  9   l , formed by a bent piece, which is welded, soldered, or glued to the outside, and which penetrates the opening  16  at the cover plate or the element with its free leg  18  and, thus forms the stop.  
         [0047]      FIG. 15  shows a stop  9   m , formed by a screw which is screwed into an opening  16 , which is provided with an internal thread  19 . Alternatively,  FIG. 16  shows a stop  9   n , in which an internal thread  20  is provided at the cover plate or the inside of the element, into which the screw  21  is screwed. Thus, the stop is here formed by the internal thread  20 .  
         [0048]     Finally,  FIGS. 17 and 18  show another stop  9   o , in which a screw  21  is used as well, however, here it is provided in a part  22  comprising an internal thread, which is to be provided at the exterior of the cover, and, as shown in  FIG. 18 , may also be held at a distance via a spacer  23 . The screw penetrates the cover plate at a non-profiled opening  16 .  
         [0049]     The stop is not limited to the shown embodiments, and other embodiments are possible. Depending on the stop form, additionally an appropriate sealing agent such as a glue, a sealant, or a gasket might be required. Open stops, for example open impressions, are beneficially provided at stop elements, the sealing then occurs via the cover plate. Closed impressions or closed stop forms, e.g., by way of pressed-in pins or rivets or screws etc. may be realized in either of the two components.  
       LIST OF REFERENCE CHARACTERS  
       [0000]    
       
           1  Camshaft adjuster  
           2  Stator  
           3  Rotor  
           4  Protrusions  
           5  Chamber  
           6  Chamber  
           7  Vane  
           8  interior wall of the stator  
           9  Stop  
           9   a  Stop  
           9   o  Stop  
           10  Cover plate  
           11  opening  
           12  stop element  
           13  Radius  
           14  Circular shoulder  
           15  internal thread  
           16  opening  
           17  welded, soldered, or glued connection  
           18  leg  
           19  internal thread  
           20  internally threaded part 
         21  screw      
           22  internally threaded part  
           23  spacer