Abstract:
A vibration damper and a drive shaft comprising a vibration damper having a small radial extent is provided. A first shaft part is provided with a sleeve and a second shaft part is provided with an inner part which extends axially into the sleeve. The sleeve and the inner part include longitudinal rotary drivers that engage negative profiles of an damping part which is elastically deformable in the direction of shaft rotation and includes at least one decoupling ring and at least one pair of rotation limiting rings.

Description:
This application is a National Phase of PCT International Application No. PCT/DE2012/000797, filed Aug. 4, 2012, which claims priority under 35 U.S.C. §119 from German Patent Application No. 10 2011 110 021.4, filed Aug. 11, 2011, the entire disclosures of which are expressly incorporated by reference herein. 
     BACKGROUND AND SUMMARY OF THE INVENTION 
     The invention relates to a drive shaft comprising connecting parts which are arranged on each end of said drive shaft and which are designed for a rotationally locked connection with connecting components, and comprising a vibration absorber, which is arranged between said connecting components. 
     A vibration damper conforming to its genre is described in International patent publication no. WO 2010/102611 A1. 
     The object of the present invention is to improve the aforementioned vibration damper of the prior art. 
     This engineering object is achieved in that there is a decoupling ring, which comprises recesses, in addition to the negative profiles; and in that there is at least one pair of rotation limiting rings, which are free of additional recesses, and in that the decoupling ring is arranged axially along the longitudinal axis between the rotation limiting rings. 
     One embodiment provides that at least one portion of the rotary drivers and each of the associated negative profiles are constructed and coordinated with each other in such a way that at least one pocket is formed between the rotary drivers and each of the associated negative profiles. 
     One embodiment includes that at least one portion of the rotary drivers and each of the associated negative profiles are constructed and coordinated with each other in such a way that a pocket is formed between the rotary drivers and each of the associated negative profiles on each of the flanks of the rotary drivers. 
     One embodiment provides that the rotary drivers of the inner part and each of the associated negative profiles of the rotation limiting rings are constructed and coordinated with each other in such a way that a pocket is formed between the rotary drivers of the inner part and each of the associated negative profiles of the rotation limiting rings on each of the flanks of the rotary drivers. 
     One embodiment includes that the recesses of the decoupling ring are constructed as longitudinal grooves on the outer face and the inner face of the decoupling ring. In this case the outer face is the region of the damping part that faces the sleeve; and the inner face is the region of the damping part that faces the inner part. 
     One embodiment provides that the negative profiles and the recesses of the decoupling ring alternate over the periphery of the decoupling ring. At the same time different numbers of negative profiles and recesses alternate. Preferably in this case the negative profiles and the recesses relate to those negative profiles and recesses that are arranged, for example, in the manner of grooves, in the respective outer face or inner face, that is, in the same (inner/outer) face. 
     One embodiment includes that two recesses, which are formed as grooves of the outer face or the inner face, are arranged over the periphery of the decoupling ring between two negative profiles, which are constructed as grooves of the outer face or the inner face of the decoupling ring. Therefore, in this embodiment two recesses of the outer face may be found between each of the two negative profiles of the outer face. The same applies to the negative profiles or recesses of the inner face. 
     The invention also relates to a drive shaft with a vibration damper according to one of the above embodiments. This embodiment provides that each end has connecting parts for a rotationally locked connection with connecting components; and that the vibration damper is arranged between said connecting components. As a result, the drive shaft can comprise, for example joints and/or a displacement unit. The drive shaft can be used, for example, in a drive train of a motor vehicle as the longitudinal shaft and/or the side drive shaft. In this case said drive shaft has rotationally locked end regions for a rotationally locked connection with additional connecting components of the drive train, such as the transmission output shafts, differential input shafts or the differential output shafts, wheel hubs and the like, and is disposed between said connecting components of the vibration damper described above. 
     Other objects, advantages and novel features of the present invention will become apparent from the following detailed description of one or more preferred embodiments when considered in conjunction with the accompanying drawings. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG. 1  is a partially cut view of a drive shaft with a vibration damper according to an embodiment of the invention. 
         FIG. 2  an exploded view of the damping part of a vibration damper according to the invention. 
         FIG. 3  a portion of a cross section of a ring of the damping part from  FIG. 2 . 
         FIG. 4  a portion of a cross section of another ring of the damping part from  FIG. 2 . 
     
    
    
     DETAILED DESCRIPTION 
       FIG. 1  shows the drive shaft  1  comprising a vibration damper  2  and the linear displacement unit  3 , and the axis of rotation or the axis of symmetry or the longitudinal axis  100 . The vibration damper  2  is integrated into the drive shaft  1  by means of the first and second shaft parts  6 ,  7 . The first shaft part  6  is designed in the form of a sleeve  8 , into which the inner part  9  of the second shaft part  7  or more specifically the end region  9 . 1  of the inner part  9  is inserted axially. The damping part  10  is disposed radially between the sleeve  8  and the inner part  9 ; and this damping part is configured so as to be elastic; and/or this damping part contains elastic elements. The sleeve  8  and the inner part  9  comprise rotary drivers for the damping part  10  so that the torque, which is to be transmitted by means of the drive shaft  1 , is transferred; and peak torques, which occur, for example, in the case of jerks in the drive, torsional vibrations and the like, are filtered, in that the peak torques give rise to a temporary storage buffer and/or an elimination by conversion into heat in the damping part. A constant velocity joint  11  is integrated in the vibration damper  2 . For more details of the description of  FIG. 1  see WO 2010/102611 A1. 
     The vibration damper  10  from  FIG. 2  consists of three rings; or, as an alternative said vibration damper may also consist of more than three rings; and these rings are arranged one behind the other along the longitudinal axis. In this case the two outer rings  50  (hereinafter referred to as: rotational angle limiting ring) are identical in their construction in this embodiment, and the center ring  51  (hereinafter referred to as: decoupling ring) has a considerably greater height than the other two rings  50 . In one embodiment the rings  50 ,  51  are made of a synthetic plastic material and, in particular, are not made of a pure elastomer. These rings can have substantially identical or also different material properties. For example, they can exhibit varying rigidity. One advantage of the different designs of the rings  50 ,  51  is that the requirements for the damping part  10 , good damping properties and a low rigidity, are fulfilled. The friction between the individual rings  50 ,  51  makes it possible to achieve an even greater degree of damping. In order to achieve damping, the energy must be extracted from the system in the form of heat, for which purpose the components involved are moved in rotation. The type of movement can be adjusted by the geometry of the negative profiles and/or the recesses. 
     The damping element  10  has two rotational angle limiting rings  50 , which are guided radially between the sleeve and the inner part. Between the rotational angle limiting rings  50  there is a decoupling ring  51  with additional recesses that allow the decoupling ring  51  to rest freely between the sleeve and the inner part in the radial direction. The decoupling ring  51  does not have any radial guidance functions, but rather fulfills in essence only the function of damping. 
     In order to illustrate clearly the construction of the vibration damper,  FIG. 3  shows a portion of a cross section of the vibration damper with the sleeve  8  and the inner part  9  and the rotational angle limiting ring  50 , which is arranged radially between said sleeve and said inner part. The sleeve  8 , which is made, for example, of a metal and is produced, for example, from a suitably formed tubing material, has rotary drivers  11 , which are configured in the embodiment shown in the form of longitudinal ribs, which extend radially inwards and axially along the sleeve  8 . Distributed over the periphery, rotary drivers  13 , which are directed radially outwards, are provided in the form of longitudinal ribs on the inner part  9 . The rotational angle limiting ring  50  of the damping part is received in a rotationally locked fashion in the rotary drivers  11 ,  13 . 
     For this purpose the rotational angle limiting ring  50  has corresponding negative profiles  15 ,  16 , which in this case are formed by longitudinal grooves and which are pushed onto each of the rotary drivers  11 ,  13 . The longitudinal grooves have the advantage that they offer large areas for the transmission of compressive forces. The rotational angle limiting ring  50  makes contact with its outer face or inner face with each of the walls of the sleeve  8  or more specifically the inner part  9  between the rotary drivers  11 ,  13 , as a result of which a radial guide is produced. The negative profiles  13 , which are constructed as grooves on the inner face of the rotational angle limiting ring  50  that faces the inner part  9 , and the rotary drivers  13  of the inner part  9  are constructed and coordinated with each other in such a way that in each case they produce pockets  60 , which are laterally adjacent to the flanks of the rotary drivers  13  of the inner part  9 . 
     The decoupling ring  51  of the damping part from  FIG. 4  has, in addition to the negative profiles  15 ,  16 , two recesses  40 ,  41  between the sleeve  8  and the inner part  9 , where, as an alternative, it is also possible for there to be more than two recesses; and these recesses do not receive the rotary drivers  11 ,  13 . In this case the recesses  40 ,  41  are constructed as grooves of the outer face  70  and the inner face  71  of the decoupling ring  51 , once on the radially outwards oriented outer face  70  in the direction of the sleeve  8  (recesses  40 ) and once on the radially inwards oriented inner face  71  in the direction of the inner part  9  (recesses  41 ). In this respect two recesses  40  are provided between each of two negative profiles  15 , which are constructed as grooves of the outer face  70  of the decoupling ring  51 . These two recesses are also constructed as grooves in the outer face  70  of the decoupling ring  51 . The same applies to the inner face  71  and its negative profiles  16  or the recesses  41 . In this case there is a groove of a negative profile  15  of the outer face  70  of the decoupling ring  51  between two grooves  41 , which are grooves of the inner face  71 , in the circumferential direction. Furthermore, the material web between two recesses  40 ,  41  of the outer face  70  and/or the inner face  71  of the decoupling ring  51  in the direction of each contacting components (that is, the sleeve  8  or the inner part  9 ) is kept as narrow as possible. As a result, the contact face of the decoupling ring  51  is lowered onto the sleeve  8  or onto the inner part  9 . Furthermore, the decoupling ring  51 , the sleeve  8  and the inner part  9  are designed in such a way that the decoupling ring  51  is radially free between the sleeve  8  and the inner part  9 . The force is applied by way of the lateral contact of the decoupling ring  51  with the flanks of the rotary drivers  11 ,  13 . 
     The foregoing disclosure has been set forth merely to illustrate the invention and is not intended to be limiting. Since modifications of the disclosed embodiments incorporating the spirit and substance of the invention may occur to persons skilled in the art, the invention should be construed to include everything within the scope of the appended claims and equivalents thereof.