Patent Publication Number: US-2021172487-A1

Title: Disc brake for a commercial vehicle

Description:
FIELD 
     The present disclosure relates to a disc brake. More particularly, the present disclosure relates to a disc brake for a commercial vehicle, having a brake caliper and brake pads which clamp a brake disc, where the brake caliper has a first inside space with an opening on the side facing a brake disc for receiving a clamping device, and the brake caliper has a second inside space for receiving the brake disc. 
     BACKGROUND 
     Disc brakes for commercial vehicle are known, for example, from DE 10 2012 016 712 A1. The disc brake has a brake caliper for a sliding caliper disc brake. By way of two bolt guides inset in the brake caliper, the brake caliper slides axially in the direction of the brake disc on guide bolts of a brake carrier of the disc brake and clamps the brake disc during a braking operation. The brake carrier has two brake pad channels located opposite one another for the receiving and arrangement of the brake pads. The brake pads are guided and supported in the brake carrier so as to be axially displaceable. The brake pads are held by a pad retaining clip and by retaining springs. A disadvantage of brake carriers for commercial vehicles, in particular for heavy commercial vehicles, is their high inherent weight of at least 9 kg. Within the first inside space there is arranged an actuator in the form of a clamping device, which clamps the clamping-side brake pad via the opening of the first inside space. Current clamping devices require a large amount of installation space in the brake caliper for their arrangement. The clamping side is defined as the side of the disc brake on which the clamping device is arranged in the disc brake. The reaction side is defined as the side of the disc brake opposite the clamping side. For correcting pad wear of the brake pads, the clamping device of the disc brake has an adjusting device. The adjusting device is designed to keep a clearance, that is to say the distance between the brake pad and the brake disc, constant. In modern disc brakes, adjustment takes place automatically. The adjusting device, like the clamping device, is arranged in the first inside space of the brake caliper or in an additional inside space of the brake caliper in the form of a box core, so that the brake caliper must have sufficiently large axial and radial dimensions to receive the clamping device and the adjusting device. 
     New brake concepts tend towards a narrower structural form of the clamping device. The narrow structural form of the clamping device is the result of reduced pad thicknesses of the brake pads, which permit an axial arrangement with the same installation length as clamping and adjusting devices arranged in parallel. Such a clamping unit with reduced installation space is shown, for example, in DE 10 2017 004 436 A1. 
     SUMMARY 
     The object of the present disclosure is to provide a disc brake having a brake caliper and brake pads which provides advantages in terms of installation space, is lightweight, and reduces production costs. 
     The object is achieved by arranging lugs for receiving brake pads in a second inside space of a brake caliper of a disc brake. By the arrangement of the lugs within the brake caliper, the brake carrier for receiving the brake pads can be omitted, so that the overall weight of the disc brake and the production costs are reduced. With the omission of the brake carrier, installation space is additionally freed within a vehicle, and this additionally freed space can be used in other ways. Further advantages include reduced dimensions of the disc brake for transport purposes and simplified construction during mounting, because additional components, such as the brake carrier, are no longer included. The arrangement of lugs for receiving the brake pads directly in the brake caliper is particularly suitable for a brake caliper that receives, in a first inside space of the brake caliper, a clamping unit that is narrow in width and length and arranged in succession. As a result of the small dimensioning of the clamping unit, additional free space is produced in the brake caliper. The lugs can be arranged in the free space that is additionally available in the brake caliper without having to increase the dimensions of the brake caliper. 
     In one aspect, two lugs are arranged opposite one another and form a pad carrier channel for receiving the brake pad. A brake pad carrier channel is arranged on the clamping side in the second inside space of the brake caliper of the disc brake. A further brake pad carrier channel is arranged in the second inside space of the brake caliper of the disc brake, in an axially parallel manner with respect to the brake disc, on the reaction side, opposite the clamping side. The pad carrier channel facilitates mounting of the brake pads belonging to the disc brake. Only brake pads of the correct dimensions in terms of size fit into the brake pad carrier channels formed by the lugs. The size of the brake pads is to be understood as being the length, the width and the depth of a brake pad. 
     In a further aspect, two axial cross-members of the brake pad each have two sub-regions which are located in the direction of the second inside space and are in the form of lugs. More sub-regions from which the lugs are formed are also conceivable on the axial cross-members. The sub-regions on the axial cross-members limit the brake pads in a perpendicular direction relative to the axial axis of the brake caliper without an additional outlay in terms of material. The region of the brake disc run-in and the region of the brake disc run-out remain free of sub-regions that are in the form of lugs. 
     In a further aspect, the lugs are L-shaped, such that the brake pads are arranged in the brake caliper so as to be secured against canting and twisting. The L-shaped form of the lugs additionally prevents or substantially limits the brake pads from being rotated out of the brake caliper. 
     In a further aspect, the lugs and the brake caliper are formed from a single component, such that costs in the production process are reduced. 
     In a further aspect, the brake caliper having the lugs formed from one component is formed from a torsion-resistant cast part or from an aluminum component, which is easy to machine, or a component formed from a composite material, which is also easy to machine. As well as being easy to machine, aluminum and composite materials additionally have a light overall weight relative to other materials. Moreover, the lugs formed from aluminum or composite material can easily be formed from the component, for example by rolling or stamping processes, and reworked. 
     In a further aspect, the first inside space is configured to receive a clamping device and an adjusting device. The arrangement of the clamping device and the adjusting device axially in succession, and also the arrangement thereof in the first inside space of the brake caliper, requires less installation space in the brake caliper. Accordingly, the first inside space of the brake caliper can be of smaller dimensions and, in addition, installation space is present in the second inside space of the brake caliper for the arrangement of the lugs. Additionally, additional installation space is present for receiving the brake pads in the lugs. 
     Advantageously, the brake pads have supporting surfaces for arrangement on the lugs. For securing against twisting, the brake pads have, on their perimeter, supporting surfaces which correspond in terms of their dimensions (length and depth or height and depth) to the lugs. 
     In a further aspect, supporting surfaces of the brake pad lie on the lugs perpendicularly to the axial axis of the brake caliper and lie on the lugs in the radial direction. The supporting surfaces advantageously form a type of coding. The fitting of incorrect brake pads is prevented, because only brake pads in which the supporting surfaces correspond to the lugs of the brake caliper fit into the brake caliper. 
     In a further aspect, the axial length of the supporting surfaces of the brake pad arranged on the clamping side of the disc brake is smaller than an axial length of the lugs on the clamping side of the brake caliper. The additional length of the lugs on the clamping side of the brake caliper allows the clearance to be adjusted by way of displacement of the brake caliper in the direction of the brake disc. The clearance is defined as the distance between the brake disc and the brake pad. 
     Furthermore, in a further aspect, the axial length of the lugs on the clamping side of the brake caliper is formed from the sum of the axial length of the clamping-side support surfaces, a degree of wear of the reaction-side brake pad and a degree of wear of the brake disc. The axial length of the lugs on the clamping side of the brake caliper accordingly corresponds to the maximum clearance adjustment of the clamping-side brake pad, and accordingly to the maximum wear of the clamping-side brake pad and the maximum wear of the reaction-side brake pad. 
     In a further aspect, the brake caliper of the disc brake has, axially, two bolt guides for arrangement on an axle flange on the vehicle. A bolt guide cap is arranged coaxially on each of the two bolt guides for protection against environmental influences and corrosion. The brake caliper of the disc brake is fixed to an axle flange on the vehicle via two bolt screws each arranged in a bolt guide. Further fastening means for arrangement of the disc brake on the axle flange on the vehicle are not necessary. 
     In a further aspect, the bolt guide caps are arranged on the bolt guides via a screw connection or a clip connection. The screw connection and the clip connection have the advantage of simple fitting and simple removal of the bolt guide caps. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       Selected exemplary embodiments of the invention will be explained herein below by way of the accompanying figures, in which: 
         FIG. 1  is a perspective view of a disc brake having a brake caliper with lugs, 
         FIG. 2  is a perspective view of a clamping-side brake pad of the brake caliper according to  FIG. 1 , 
         FIG. 2 a    is a perspective view of a reaction-side brake pad of the brake caliper according to  FIG. 1 , 
         FIG. 3  is a perspective view of the brake caliper of the disc brake according to  FIG. 1 , 
         FIG. 3 a    is another perspective view of the brake caliper of the disc brake according to  FIG. 1 , 
         FIG. 3 b    is yet another perspective view of the brake caliper of the disc brake according to  FIG. 1 , 
         FIG. 4  is another perspective view of the disc brake according to  FIG. 1  having the brake caliper according to  FIGS. 1 and 3, 3   a ,  3   b.    
     
    
    
     DETAILED DESCRIPTION OF THE DRAWINGS 
       FIG. 1  shows a disc brake having a brake caliper  2 , according to the present disclosure. In the brake caliper  2 , starting from an axial axis A of the brake caliper  2  on the clamping side, a recess in the form of a first inside space  4  is disposed for receiving a clamping device  7  that is arranged axially in succession. The clamping device  7  clamps a brake disc  6  via the clamping-side brake pad  3 , the reaction-side brake pad  3   a,  and via an opening  5  that extends axially in the direction of the brake disc  6  and that is provided in the first inside space  4 . For receiving a clamping-side brake pad  3  and a reaction-side brake pad  3   a,  and a brake disc  6  arranged between the clamping-side brake pad  3  and the reaction-side brake pad  3   a,  the brake caliper  2  has a second inside space  8 . In the direction of the second inside space  8  of the brake caliper  2 , sub-regions  12 ,  12   a  are formed on a first axial cross-member  11  and sub-regions  12   b,    12   c  are formed on a second axial cross-member  11   a.    
     Lugs  9 ,  9   a,    9   b,    9   bb,    9   c,    9   cc  are formed from the sub-regions, where the lug  9   bb  and the lug  9   cc  are shown in  FIG. 3 . The lugs  9 ,  9   a  are L-shaped and disposed on opposite lateral sides of the axis A, and the lugs  9 ,  9   a  form a pad carrier channel  10  in the lateral space therebetween for receiving the brake pad  3 . Lugs  9   b,    9   c  are also disposed on opposite lateral sides, and the lugs  9   b,    9   c  form a pad carrier channel  10   a  in the lateral space therebetween for receiving the brake pad  3   a.  The lugs  9 ,  9   a  have axially a length Ly in the axial direction, which corresponds to a combination of an axial length L of the brake pad  3  and a pad wear X of the reaction-side brake pad  3   a.  A pad wear X (see  FIG. 2 a   ) is to be understood as meaning the deterioration of a friction lining  20  of the reaction-side brake pad  3   a.  By lengthening of the lugs  9 ,  9   a  (relative to the length L of the brake pad  3 ) by the pad wear X of the brake pad  3   a,  the displacement of the brake caliper  2 , and accordingly also the displacement of the brake pad  3 , in the direction of the brake disc  6  is taken into consideration, whereby the clamping-side brake pad  3  is prevented from falling out of the brake caliper  2 . 
     The brake caliper  2  additionally has two bolt guides  15 ,  15   a,  which are described in greater detail in  FIG. 4 . A degree of wear Y of the brake disc  6  is described in greater detail in  FIG. 2, 2   a.    
     A detailed view of the clamping-side brake pad  3  and of the reaction-side brake pad  3   a  is shown in  FIG. 2  and  FIG. 2 a   , respectively. The brake pad  3  has, on its perimeter, supporting surfaces  13 ,  13   a  and bearing surfaces  21 ,  21   a,  where the supporting surfaces  13 ,  13   a  are in contact perpendicularly (i.e. laterally) to the axial axis A of the brake caliper  2  ( FIG. 1 ) with the lugs  9 ,  9   a  of the brake caliper ( FIG. 1 ), and the bearing surfaces  21 ,  21   a,  are in contact radially (i.e. vertically) with the lugs  9 ,  9   a  ( FIG. 1 ). Similarly, the brake pad  3   a  has, on its perimeter, supporting surfaces  13   b,    13   c  and bearing surfaces  21   b,    21   c,  wherein the supporting surfaces  13   b,    13   c  are in contact perpendicularly (i.e. laterally) to the axial axis A of the brake caliper  2  ( FIG. 1 ) with the lugs  9   b,    9   c  of the brake caliper ( FIG. 1 ) and the bearing surfaces  21   b,    21   c  are in contact radially (i.e. vertically) with the lugs  9   bb,    9   cc  ( FIGS. 3 and 3   b ). The clamping-side brake pad  3  differs from the reaction-side brake pad  3   a  by the dimensioning of the bearing surfaces  21 ,  21   a,    21   b,    21   c  and of the supporting surfaces  13 ,  13   a,    13   b,    13   c.  By precisely positioning and arranging the brake pads  3 ,  3   a  on the lugs  9 ,  9   a,    9   b,    9   c,    9   bb,    9   cc  the brake pads  3 ,  3   a  are prevented from both canting and falling out of the brake caliper  2 . 
     In the case of the clamping-side brake pad  3 , the axial length Lx of the supporting surfaces  13 ,  13   a  is smaller than the axial length Ly of the lugs  9 ,  9   a  ( FIG. 1 ). The axial length Ly of the lugs  9 ,  9   a  is composed of the axial length Lx of the supporting surfaces  13 ,  13   a,  the degree of wear X of the reaction-side brake pad  3   a  and the degree of wear Y ( FIG. 1 ) of the brake disc  6 . An axial length Lz of the bearing surface  21 ,  21   a  corresponds to the axial length Ly of the lugs  9 ,  9   a  ( FIG. 1 ). In the case of the reaction-side brake pad  3   a,  an axial length Lx 1  of the supporting surfaces  13   b,    13   c  corresponds to the axial length Ly 1  of the lugs  9   b,    9   c  ( FIG. 1 ), and an axial length Lz 1  of the bearing surface  21   b,    21   c  corresponds to the axial length Ly 1  of the lugs  9   bb,    9   cc  ( FIG. 1 ). 
       FIG. 3, 3   a ,  3   b  show three views of the brake caliper  2  of the disc brake  1  according to  FIG. 1  to  FIG. 2 a   , but without brake pads  3 ,  3   a.  In particular, the L-shaped form of the clamping-side lugs  9 ,  9   a  is shown. 
     Furthermore, the axial lengthening of the clamping side lugs  9 ,  9   a,  as compared to the reaction-side lugs  9   b,    9   bb,    9   c,    9   cc,  by the pad wear X of the brake pad  3   a  ( FIG. 1 ,  FIG. 2 ,  FIG. 2 a   ) can be seen particularly clearly. 
     In  FIG. 4 , the arrangement of the bolt guide cap  18  of the bolt guide  15  and the arrangement of the bolt guide cap  18   a  of the bolt guide  15   a  is shown. The bolt guide cap  18  is screwed to the bolt guide  15 , axially in the direction of the clamping device  7 , via a thread  22  of the bolt guide  15 , and the further bolt guide cap  18   a  is screwed to the bolt guide  15   a,  axially in the direction of the clamping device  7 , via a thread  22   a  of the bolt guide  15   a.  For illustrative purposes, a bolt screw  16  for connection to a vehicle axle, not shown, is shown in the bolt guide  15   a.  For mounting of the disc brake  1  on the vehicle axle, not shown, the bolt screw  16  is screwed out of the bolt guide  15   a  once the bolt guide cap  18   a  has been unscrewed from the bolt guide  15 . The bolt screw  16  is then screwed into the bolt guide  15  again. 
     While the above description constitutes the preferred embodiments of the present invention, it will be appreciated that the invention is susceptible to modification, variation and change without departing from the proper scope and fair meaning of the accompanying claims.