Patent Publication Number: US-2005141954-A1

Title: Bearing bolt joint

Description:
The invention relates to a bearing bolt joint in accordance with the preamble of claim  1 .  
      Bearing bolt joints without clearance are already known which essentially consist of a bolt and an arrangement to fix the bolt to a machine element. The bolt has a cylindrical center part and two conically tapering end parts. The arrangement to fix the bolt consists of two inwardly conically extending expansion bushings which are axially clampable to the bolt by means of screws and washers and are thus seated without clearance in the receiving bore. With the fixed bearing, the support of a bolt in a bore must be provided with minimum clearance for reasons of assembling capability and disassembling capability. If the clearance is too large, on the one hand, the result is a fast knocking out of the bore. If, however, the clearance is too small, the assembly and disassembly is no longer ensured. In practice, it is in particular the disassembly which causes high costs.  
      To prevent the previously described knocking out, the initially described bearing bolt joints were developed and used in many areas of the construction machine industry. A description of such a bearing bolt joint already results from DE 690 11 330 T2.  
      The installation of these bushings is generally unproblematic; but it has been found that large problems occur on the dismantling under certain circumstances in that the cone-type bushings cannot be removed or can only be removed with difficulty. The reason for this can lie in the fact that worked support positions of the components cannot be completely protected against corrosion and a friction coefficient is thus adopted which makes a removal of the cone-type bushing much more difficult and sometimes even impossible. To eliminate this deficiency, holding bushings have already been developed which are connected to the required coupling nut in a shaped matched manner such that the expansion bushing can be clamped and also drawn again. The disadvantage of such a unit lies in the high price and in the greater space requirements. These are also the reasons why this type of bearing bolt joint was not able to establish itself on the market.  
      Starting from the aforesaid prior art, it is the underlying object of the present invention to provide a bearing bolt joint which can be built in a space-saving manner and which can be dismantled in a simple manner without any great additional costs.  
      This object is solved in accordance with the invention by the combination of the features of claim  1 .  
      According to this, in a generic bearing bolt joint, the expansion bushings each have a coupling region at their end pointing away from the bolt, with a pull-off tool being releasably connectable to said coupling region. For the dismantling, the corresponding pull-off tool can here be connected to the expansion bushing and the latter can be drawn in a simple manner to release the bearing bolt joint.  
      Preferred aspects of the invention result from the dependent claims following the main claim. Accordingly, the coupling region can be made as an internal thread into which a pull-off screw or pull-off sleeve can be screwed. The material thickness is the largest particularly in the rear conical region in the expansion bushings. A corresponding internal thread, into which the pull-off screw or pull-off sleeve can be screwed, can therefore be made here without problem  
      When a pull-off sleeve is used, it can advantageously be partly or fully slotted. The unscrewing or screwing in of the pull-off sleeves is also hereby made possible with variable expansion bushing diameters which are caused by the pressing on of the expansion bushing.  
      In another advantageous embodiment, the coupling region is made as a grooved surface region, for example in a recess in the expansion bushing. A correspondingly shaped engagement region of the pull-off tool can be brought into engagement with this grooved surface region. The pull-off tool provided for an expansion bushing made in this manner can itself advantageously include an expandable sleeve with a conical internal diameter which can be expanded by means of a frusto-conical contact surface.  
      The expansion bushings can advantageously, as already known as such in the prior art, be slotted at their periphery. 
    
    
      Further details, advantages and features of the invention result from the embodiments shown by way of example in the drawing. There are shown:  
       FIG. 1 : a partial section through a bearing bolt joint in accordance with a first embodiment of the present invention;  
       FIG. 2 : a representation in accordance with  FIG. 1  of a second embodiment;  
       FIG. 3 : a representation corresponding to  FIG. 1  of a third embodiment;  
       FIG. 4 : a representation corresponding to  FIG. 1  of a fourth embodiment;  
       FIG. 5 : a representation corresponding to  FIG. 1  of a fifth embodiment; and  
       FIG. 6 : a sixth embodiment variant of the present invention corresponding to an embodiment represented in  FIG. 1 . 
    
    
      A bearing bolt joint  10  in accordance with the invention is shown in  FIG. 1  in accordance with a first embodiment of the invention in which a bolt  12  is fixed in a machine element  16  by means of an arrangement to fix the bolt  14 . The bolt has a cylindrical center part  18  and two conically tapering ends  20  of which one end is shown in  FIG. 1 . Of the arrangement to fix the bolt, one of the two expansion bushings  22  is shown here which are displaceable in the arrow direction x by means of clamping means not shown in any more detail here. The expansion bushings  22  expand outwardly in the direction of the arrow y along the conically tapering ends  20  of the bolt  12  such that a fixed seating with the machine element  16  is ensured here.  
      The expansion bushing  22  has a coupling region  26  made as an internal thread  24  at the end pointing away from the bolt  12  and a pull-off sleeve which serves as a pull-off tool  28  and which has a corresponding external thread  30  can be screwed into said coupling region  26  such that the expansion bushing  22  is movable against the arrow direction x with the help of this sleeve so that it is drawn together and can be moved out of the fixed engagement with the machine element  16 .  
      Slots are arranged in a manner not shown in any more detail here at the outer periphery of the pull-off sleeve  28  and permit a reduction in the outer periphery of the pull-off sleeve. The external diameter of the pull-off sleeve can hereby be adapted to the optionally varying internal diameter of the internal thread  24 . A blind hole with an internal thread  32  is turned into the end of the bolt  12  and a screw can be screwed into it via which the expansion bushing  22  can be pushed in the x direction onto the conically tapering end  20  of the bolt by means of suitable screws and washers.  
      The embodiment shown in  FIG. 2  corresponds in substantial parts to that in accordance with  FIG. 1 . For reasons of simple representation, like parts are shown with like reference numerals here.  
      Instead of the blind hole bore  32  with an internal thread, here a screw bolt  34  with an external thread  36  is provided onto which the nuts and washers for the clamping of the expansion bushing  22  can be pulled or screwed. Due to this design difference, a lateral, central opening  38  is provided in the expansion bushing  22  and the threaded bolt  36  can project outwardly through it. The internal diameter of the internal screw connection  24  is, in accordance with the opening  38 , comparatively larger than that in the embodiment in accordance with  FIG. 1 . A pull-off sleeve not shown in any more detail in  FIG. 2  engages into this in the same way as shown in  FIG. 1 .  
      The embodiment in accordance with  FIG. 3  essentially corresponds to that in accordance with  FIG. 2 , with here no bolt with thread being provided which projects outwardly. A shoulder  40  is formed inside the expansion bushing  22  here, with the internal thread being turned in in the region of the shoulder  40 . The external thread  42  of a sleeve  44  in which a pressing screw  46  is rotatably supported can be screwed into this internal thread. The expansion bushing  22  is then drawn counter to the arrow direction x via the pressing screw  46  after a corresponding opening of the sleeve  44 .  
      The embodiment in accordance with  FIG. 4  corresponds to that in accordance with  FIG. 3 , with an external thread  25  being provided here at the expansion bushing  22  and with an internal thread  43  of the sleeve  44  being able to be screwed onto it. A pressing screw  46  is again provided here by means of which the expansion bushing  22  can be drawn corresponding to the arrow direction x.  
       FIG. 5  shows a variant in which an internal thread  24  is provided in a recess  48  inside the expansion bushing  22 , with a pull-off tool being able to be used here to draw the expansion bushing such as is shown in  FIG. 3 .  
      Another embodiment is shown in  FIG. 6 . A pull-off tool  52  essentially consists of a screw  54  which can displace a sleeve  58  having a frusto-conical region  56  in the x direction such that a spreading-cone  60  which sits on the sleeve  58  and which has a conical inner surface contacting opposite the frusto-conical surface  56  can be moved radially outwardly. The outer surface of the spreading cone  60  likewise has grooves  62  which have the negative shape of the grooves  50  of the expansion bushing  22 . The sleeve  58  can thus be displaced in the x direction by a corresponding rotation of the screw  54  and thus the spreading cone  60  can be expanded or drawn together so that the surface region with the grooves  62  can be brought into engagement with the corresponding surface region with the grooves  50  of the expansion bushing  22 . After a corresponding engagement of the groove regions  62  and  50 , the screw  54  is turned into the existing bore  32 . At the same time, the sleeve  58  is displaced by means of the thread, whereby the expansion bushing  22  is pulled out.