Abstract:
A bearing bracket configuration for a drum brake of a motor vehicle. A bearing bracket ( 30 ) for an eccentric shaft ( 20 ) is provided with a separate mounting ( 50 ) for the brake cylinder ( 10 ). This makes it possible for the fastening to be divided into separate parts, whereby accessibility for fitting is improved and it is possible for the parts to be largely preassembled. Also, a drum brake and a motor vehicle with the configuration and a method for fitting a bearing bracket configuration are disclosed.

Description:
TECHNICAL FIELD 
       [0001]    The invention relates to a bearing bracket configuration for drum brakes according to the preamble of claim  1 . The invention relates also to a drum brake and a motor vehicle. It also relates to a method for assembling a bearing bracket configuration. 
       BACKGROUND 
       [0002]    Drum brakes on rear axles of at least large motor vehicles comprise a brake cylinder, a brake lever arm connected to the brake cylinder, and an eccentric shaft connected to the brake lever arm and provided with an S cam, whereby during braking the braking force is arranged to be transmitted from the brake cylinder to the brake lever arm, which rotates the eccentric shaft so that the S cam turns and thereby pushes out the brake shoes which then press upon the brake drum to brake the vehicle. 
         [0003]    In prior art the drum brake is installed close to the rear axle via a bearing bracket which is fastened to the rear axle and adapted to journalling the eccentric shaft and serving as a mounting for the brake cylinder. 
         [0004]    Assembly involves first fastening the bearing bracket to the rear axle and then fitting the other parts by successively connecting the eccentric shaft to the bearing bracket, the brake lever arm to the eccentric shaft and the brake cylinder to the bearing bracket. 
         [0005]    Such fastening by means of the bearing bracket results in inefficient fitting of the drum brake to the rear axle, inter alia because of limited accessibility and limited scope for preassembly. 
       OBJECT OF THE INVENTION 
       [0006]    An object of the present invention is to propose a bearing bracket configuration for a drum brake of a motor vehicle which makes it easier, inter alia by possible preassembly, to fit the drum brake&#39;s brake lever arm, eccentric shaft and brake cylinder. 
       SUMMARY OF THE INVENTION 
       [0007]    This and other objects indicated by the description set out below are achieved by a bearing bracket configuration, a drum brake and a motor vehicle of the kind indicated in the introduction which further present the features indicated in the characterising parts of the attached independent claims. Corresponding advantages are achieved in a method for fitting a bearing bracket. Preferred embodiments of the bearing bracket configuration are defined in the attached dependent claims. 
         [0008]    Using a separate bearing bracket for the eccentric shaft and separate brake cylinder fastening means allows efficient fitting of the drum brake&#39;s eccentric shaft, brake cylinder and brake lever arm. Access to threaded connections is thus facilitated by clear paths for tools, resulting in easier fitting to the rear axle. It is also possible to preassemble parts of the installation, which may take place off the main assembly line, thereby making fitting still more efficient. A further possibility is that various parts of the installation may be fitted at different stations on the assembly line, resulting in better balancing of production in that not all fitting need take place at the same assembly station, since various parts may be spread over the process of axle assembly, making it possible to break fitting down into smaller portions and thereby optimise assembly cycle times. 
         [0009]    In one embodiment said bearing bracket is arranged to be fastened to the vehicle&#39;s rear axle close to said drum brake, making it possible to arrange the parts of the drum brake efficiently as regards space. 
         [0010]    In one embodiment said bearing bracket is configured to be part of an assembly package comprising said eccentric shaft, a brake lever arm connected to the eccentric shaft, and an eccentric configuration, resulting in more efficient fitting on the assembly line. 
         [0011]    In one embodiment said brake cylinder fastening means is configured to be part of an assembly package comprising said brake cylinder, resulting in more efficient fitting on the assembly line. 
         [0012]    The invention thus makes it possible for parts to be largely preassembled, thereby facilitating fitting. 
     
    
     
       DESCRIPTION OF DRAWINGS 
         [0013]    The present invention will be better understood by reading the detailed description set out below in conjunction with the attached drawings, in which the same reference notations are used for similar parts throughout the various views, 
           [0014]      FIG. 1  schematically illustrates a motor vehicle according to an embodiment of the present invention, 
           [0015]      FIGS. 2   a - 2   b  are different schematic perspective views of part of a rear axle with part of a drum brake comprising a bearing bracket configuration according to the present invention, 
           [0016]      FIGS. 3   a - b  are different schematic side views of the bearing bracket configuration in  FIGS. 2   a - b  with brake cylinder and brake lever arm, 
           [0017]      FIG. 4  is a schematic perspective view of a bearing bracket from the bearing bracket configuration in  FIGS. 2   a - b,    
           [0018]      FIG. 5  is a schematic perspective view of a brake cylinder fastening means from the bearing bracket configuration in  FIGS. 2   a - b,    
           [0019]      FIGS. 6   a - b  are different schematic perspective views of an assembly package formed with the bearing bracket in  FIG. 4  and comprising said eccentric shaft, a brake lever arm connected to the eccentric shaft, and an eccentric configuration, and 
           [0020]      FIG. 7   a  is a schematic perspective view and  FIGS. 7   b - c  are different schematic side views of an assembly package formed with the brake cylinder fastening means in  FIG. 5  and comprising said brake cylinder. 
       
    
    
     DESCRIPTION OF EMBODIMENTS 
       [0021]      FIG. 1  illustrates schematically a motor vehicle  1  according to an embodiment of the present invention. The vehicle here exemplified is a heavy vehicle in the form of a truck. It has a powered rear axle X connected to tractive rear wheels and provided with an arrangement in the form of a bearing bracket configuration for the rear axle&#39;s drum brakes. In alternative embodiments the invention may also be used on non-tractive, non-steerable wheels. 
         [0022]      FIGS. 2   a - 2   b  are different schematic perspective views of part of a rear axle X with part of a drum brake comprising a bearing bracket configuration for a drum brake of a motor vehicle according to the present invention, and  FIGS. 3   a - b  are different schematic side views of the bearing bracket configuration in  FIGS. 2   a - b  with brake cylinder  10  and eccentric shaft  20 . 
         [0023]    The bearing bracket configuration is arranged for journalled fastening of an eccentric shaft  20  of said drum brake and for fastening of a brake cylinder  10  of said drum brake. 
         [0024]    The bearing bracket configuration comprises a bearing bracket  30  for said journalled fastening of an eccentric shaft  20 . Said bearing bracket is adapted to being fastened to the vehicle&#39;s rear axle X close to said drum brake. 
         [0025]    The eccentric shaft  20  is thus journalled by said bearing bracket. The eccentric shaft is connected to a substantially annular eccentric configuration  40  placed round said rear axle X close to an undepicted brake drum of said drum brake. 
         [0026]    Said eccentric shaft  20  is arranged to run substantially parallel with and at a distance from the rear axle X, i.e. eccentrically relative to the rear axle X. Said eccentric shaft is journalled by a bearing  42  in said eccentric configuration. Said eccentric shaft is connected to a substantially S-shaped cam, referred to as the cam S. In one variant said cam S is an integral part of said eccentric shaft. 
         [0027]    The bearing bracket configuration comprises a separate brake cylinder fastening means  50  for said fastening of a brake cylinder  10  which is part of said drum brake. 
         [0028]    Said bearing bracket  30  is adapted to accommodating said separate brake cylinder fastening means  50  for said fastening of a brake cylinder  10 . Said brake cylinder fastening means is adapted accordingly to being fastened to said bearing bracket. 
         [0029]    Said drum brake comprises a brake lever arm  60 . Said brake lever arm has in its lower end region a lower fastening portion  62  provided with a fastening aperture  62   a  and connected pivotably to a fastening portion  12  of the brake cylinder  10 , and in its opposite upper end region an upper fastening portion  64  connected to, for rotation of, said eccentric shaft  20 . 
         [0030]    During braking, the braking force is arranged to be transmitted from the brake cylinder  10  to the brake lever arm  60  which is adapted to rotating the eccentric shaft  20  so that the cam S turns and thereby pushes out undepicted brake shoes of the drum brake which during said braking are adapted to pressing upon the drum brake&#39;s undepicted brake drum to brake the vehicle. 
         [0031]      FIG. 4  is a schematic perspective view of said bearing bracket  30  which is part of the bearing bracket configuration in  FIGS. 2   a - b.    
         [0032]    The bearing bracket  30  has a central bearing portion  32  which has running through it a circular bearing aperture  32   a  surrounded by a bearing  32   b  to journal said eccentric shaft  20 . 
         [0033]    The bearing bracket further has an upper region situated above the central bearing portion  32  and a lower region situated below the central bearing portion. 
         [0034]    The bearing bracket has in the upper region an upper shaft fastening portion  34  for fastening to said rear axle X and provided with an upper shaft fastening aperture  34   a  running through it and arranged to run above and substantially at right angles to the axial extent of said bearing aperture  32   a.    
         [0035]    The bearing bracket has in the lower region a lower axle fastening portion  36  for fastening to said rear axle X and provided with a lower axle fastening portion  36   a  running through it and adapted to running below and substantially at right angles to the axial extent of said bearing aperture  32   a  and parallel with said upper shaft fastening aperture  34   a.    
         [0036]    Said bearing bracket  30  is adapted to being fastened to said rear axle X by means of fastening elements situated in said upper and lower shaft fastening apertures  34   a ,  36   a  in the form of threaded connections  70 ,  71 , depicted inter alia in  FIG. 2   b . Said upper and lower shaft fastening portions  34 ,  36  and consequently said upper and lower shaft fastening apertures  34   a ,  36   a  have at right angles to the axial extent of the bearing aperture  32   a  an extent which is greater than the radial extent of the central bearing portion  32  and the bearing aperture  32   a  in corresponding directions so that when fastened to the rear axle X the eccentric shaft  20  placed in the bearing aperture  32   a  runs parallel with and at a distance from the rear axle X. 
         [0037]    The bearing bracket  30  has in an upper region an upper fastening portion  38  for said separate brake cylinder fastening means  50  with an upper aperture  38   a  and adapted to running substantially parallel with said bearing aperture  32   a  and at right angles to said shaft fastening apertures  34   a ,  36   a.    
         [0038]    The bearing bracket has in the lower region a lower fastening portion  39  for said separate brake cylinder fastening means  50 , with first and second lower apertures  39   a ,  39   b  arranged to run parallel with and at a distance from one another and substantially parallel with said bearing aperture  32   a  and at right angles to said shaft fastening apertures  34   a ,  36   a.    
         [0039]      FIG. 5  is a schematic perspective view of said brake cylinder fastening means  50  which forms part of the bearing bracket configuration in  FIGS. 2   a - b.    
         [0040]    The brake cylinder fastening means  50  comprises an intermediate portion  52 , an upper region situated above the intermediate portion, and a lower region situated below the intermediate portion. 
         [0041]    The brake cylinder fastening means  50  has in the upper region an upper fastening portion  54  for said bearing bracket  30  with an upper aperture  54   a  intended, for fitting purposes, to be brought into line with said upper aperture  38   a  in the upper fastening portion  38  of the bearing bracket, which upper fastening portion  54  of the brake cylinder fastening means is arranged to be fastened to the upper fastening portion  38  of the bearing bracket by means of a fastening element in the form of a threaded connection  72  depicted in  FIG. 2   a.    
         [0042]    The brake cylinder fastening means has in the intermediate portion  52  an intermediate fastening portion  53  for said bearing bracket  30 , with first and second intermediate apertures  53   a ,  53   b  arranged to run parallel with and at a distance from one another and intended, for fitting purposes, to be brought into line with said first and second apertures  39   a ,  39   b  in the lower fastening portion  39  of the bearing bracket, which intermediate fastening portion  53  of the brake cylinder fastening means is arranged to be fastened to the lower fastening portion  39  of the bearing bracket by means of fastening elements in the form of threaded connections  73 ,  74 . 
         [0043]    The brake cylinder fastening means has in the intermediate portion  52  a brake cylinder fastening portion  55  situated substantially at right angles to the main direction of extent of the brake cylinder fastening means, for fastening the brake cylinder  10 , with an aperture  55   a  arranged to run axially substantially at right angles to said upper aperture  54   a  and first and second intermediate apertures  53   a ,  53   b . The intermediate brake cylinder fastening portion  55  of said brake cylinder fastening means is adapted to being fastened to the brake cylinder  10  by means of a fastening element in the form of a threaded connection  75 . 
         [0044]    The brake cylinder fastening means has in the lower region a lower brake cylinder fastening portion  58  for fastening said brake cylinder  10 , with a lower aperture  58   a  arranged to run parallel with and at a distance from the aperture  55   a  in the intermediate brake cylinder fastening portion  55 . The lower brake cylinder fastening portion  58  of said brake cylinder fastening means is adapted to being fastened to the brake cylinder  10  by means of a fastening element in the form of a threaded connection  76 . 
         [0045]    The brake cylinder fastening means has in the lower region a recess  59  for weight reduction. 
         [0046]      FIGS. 6   a - b  are different schematic perspective views of a first assembly package I formed with the bearing bracket  30  in  FIG. 4  and comprising said eccentric shaft  20 , a brake lever arm  60  connected to the eccentric shaft, and an eccentric configuration  40 . 
         [0047]    Said bearing bracket  30  is configured to be part of a first assembly package I comprising said eccentric shaft, a brake lever arm connected to the eccentric shaft, and said eccentric configuration. 
         [0048]    The first assembly package I comprises accordingly said eccentric shaft  20  journalled in the bearing in said central bearing portion  32  whereby the end of the eccentric shaft opposite to that at which said cam S is situated protrudes through the bearing bracket  30  so that said brake lever arm  60  can be fastened to the protruding end of the eccentric shaft, which fastening in one variant takes the form of positive locking by splined connection. 
         [0049]    Said eccentric shaft  20  is journalled in said bearing  32   b  of said eccentric configuration  40  whereby the eccentric shaft protrudes through said bearing aperture  32   a  so that said brake lever arm  60  can be fastened to the protruding end of the eccentric shaft. 
         [0050]    The first stage in fitting said first assembly package I is to fit the eccentric shaft  20  in said eccentric configuration  40  so that by means of the bearing  42  the eccentric configuration journals the eccentric shaft close to the end of the shaft at which said cam S is situated. The next step is to fit the eccentric shaft  20  to the bearing bracket  30  so that by means of the bearing  32   b  it is journalled by the end of the bearing bracket opposite to that which is provided with the cam S. The brake lever arm  60  is then fitted to the end of the eccentric shaft close to said bearing bracket. 
         [0051]    Assembling said first assembly package I may with advantage take place separately from an assembly line before being fitted on the assembly line, in order thereby to make fitting said drum brake more efficient. 
         [0052]    Said first assembly package I is then arranged to be fitted to the rear axle X by said substantially annular eccentric configuration  40  being placed round the rear axle X so that said cam S is level with said undepicted brake shoes to make it possible for them to be pressed against the drum brake during braking. Said bearing bracket  30  is then adapted to being fitted to the rear axle X by applying said fastening elements  70 ,  71 ,  72  in said upper and lower shaft fastening apertures which are thus readily accessible for the operator. 
         [0053]      FIG. 7   a  is a schematic perspective view and  FIGS. 7   b - c  are different schematic side views of a second assembly package II formed with the brake cylinder fastening means  50  in  FIG. 5  and comprising said brake cylinder  10 . 
         [0054]    Said brake cylinder fastening means is configured to be part of said second assembly package II comprising said brake cylinder. 
         [0055]    The second assembly package II comprises accordingly said brake cylinder fastened to said brake cylinder fastening means  50  as above. 
         [0056]    Said second assembly package II is adapted to being fitted to the bearing bracket  30  by said brake cylinder fastening means being fastened to said bearing bracket as above. 
         [0057]    Said brake lever arm  60  is then adapted to being pivotable at said lower fastening portion  62  by connection to the fastening portion  12  of the brake cylinder  10 . 
         [0058]    Assembling said second assembly package II may with advantage take place separately from an assembly line before being fitted on the assembly line, after the first assembly package I has been fitted, in order thereby to make fitting said drum brake more efficient. 
         [0059]    A suitable method for assembling the bearing bracket configuration thus comprises the parts being preassembled in a first assembly package I as described above. This is followed by fitting assembly package I to the axle close to the drum brake, and finally by fitting assembly package II to the bearing bracket  30 . 
         [0060]    The above description of the preferred embodiments of the present invention is provided for illustrative and descriptive purposes. It is not intended to be exhaustive, nor to limit the invention to the variants described. Many modifications and variations will obviously suggest themselves to one skilled in the art. The embodiments have been chosen and described in order best to explain the principles of the invention and their practical applications, and thereby enable one skilled in the art to understand the invention for different embodiments and with the various modifications appropriate to the intended use.