Patent Publication Number: US-2019186567-A1

Title: Brake caliper

Description:
TECHNICAL FIELD 
     The present invention relates to a brake caliper and a method of manufacturing a brake caliper. 
     SUMMARY 
     According to an aspect of the present invention there is provided a brake caliper having: a first portion defining a housing adapted to receive an actuating mechanism, a second portion spaced from the first portion thereby defining a plane of rotation of a brake rotor, the second portion defining a first side facing the first portion and a second side facing away from the first portion, a first bridge connecting the first portion to the second portion, and a second bridge spaced from the first bridge and connecting the first portion to the second portion, the first portion, second portion, first bridge and second bridge being cast as a single casting, the second portion having a hole extending through the second portion from the first side to the second side, the hole defining a wall of the hole, the caliper further including a brake pad having a brake pad backplate, the brake pad backplate having a projection received in the hole, the projection having a rim, at least a portion of the rim engaging a portion of the wall to react circumferential forces between the brake pad and caliper in use. 
     At least a further portion of the rim may engage a further portion of the wall to react radial forces between the brake pad and caliper in use. 
     The brake caliper may define a circumferential direction and radial direction. 
     The hole may define a circumferential dimension and a radial dimension, the circumferential dimension may be larger than the radial dimension. 
     The circumferential dimension may define a first and second circumferential end of the hole, the first and/or the second circumferential end may be curved. 
     The radial dimension may define first and second radial ends of the hole, the first and/or the second radial end may include a straight portion. 
     The first side of the second portion may include a flat portion surrounding the hole and the brake pad backplate may engage the flat portion in use. 
     The flat portion may be parallel to the plane of rotation of a brake rotor. 
     The wall may be a first wall, the hole may be a first hole the projection may be a first projection, and the rim may be a first rim, the second portion may have a second hole extending through the second portion from the first side to the second side, the second hole may define second wall of the second hole, the brake pad backplate may have a second projection received in the second hole, the second projection may have a second rim, at least a portion of the second rim engaging a portion of the second wall to react circumferential and/or radial forces between the brake pad and caliper in use. 
     The first hole may be circumferentially spaced apart from the second hole by a land, the brake caliper including a retention device for securing the brake pad in the caliper in use, a portion of the retention device being attached via a fixing device to the land. 
     The fixing device may be fixed in a hole, preferably a threaded hole in the land. 
     According to a further aspect of the present invention there is provided a method of manufacturing a brake caliper including the steps of: a) casting a brake caliper to provide a bare casting having a first portion defining a housing adapted to receive an actuating mechanism, a second portion spaced from the first portion thereby defining a plane of rotation of a brake rotor, the second portion defining first side facing the first portion and a second side facing away from the first portion, a first bridge connecting the first portion to the second portion, and a second bridge spaced from the first bridge and connecting the first portion to the second portion, b) forming a hole in the second portion, the hole extending through the second portion from the first side to the second side, the hole defining a wall and c) machining a part of the wall from the second side. 
     The step of forming the hole may be carried out during casting of the bare casting. 
     The step of machining a part of the wall may include machining a part of the wall proximate the first side. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       The invention will now be described, by way of example only, with reference to the accompanying drawings in which: 
         FIG. 1  shows an isometric view of a brake caliper according to the invention, 
         FIG. 2  shows an alternative isometric view of the brake caliper of  FIG. 1 , 
         FIG. 3  shows a side view of the brake caliper of  FIG. 1 , 
         FIG. 4  shows a cross-section isometric view of the brake caliper of  FIG. 1 , 
         FIG. 5  shows a cross-section of the brake caliper of  FIG. 1 , 
         FIG. 6  shows a brake pad for use in the brake caliper of  FIG. 1  or  FIG. 7 , 
         FIG. 7  shows an isometric view of a further embodiment of the brake caliper according to the present invention, 
         FIG. 8  shows an isometric cross-section view of the brake caliper of  FIG. 6 , 
         FIG. 9  shows a side view of part of the brake caliper of  FIG. 7 , 
         FIG. 10  shows an isometric view of a component for use with the brake calipers of  FIGS. 1 and 7 , 
         FIG. 11  shows an isometric view of an alternative component for use with the brake calipers of  FIGS. 1 and 7 , and 
         FIG. 12  shows part of the component of  FIG. 11 . 
     
    
    
     DETAILED DESCRIPTION 
     As required, detailed embodiments of the present invention are disclosed herein; however, it is to be understood that the disclosed embodiments are merely exemplary of the invention that may be embodied in various and alternative forms. The figures are not necessarily to scale; some features may be exaggerated or minimized to show details of particular components. Therefore, specific structural and functional details disclosed herein are not to be interpreted as limiting, but merely as a representative basis for teaching one skilled in the art to variously employ the present invention. 
     With reference to  FIGS. 1 to 6  there is shown a brake caliper  10  having a first portion  12  defining a housing  40  and a second portion  14 . The second portion is spaced from the first portion thereby defining a plane P of rotation of a brake rotor  20 . 
     The first portion  12  is connected to the second portion  14  by a first bridge  16  and a second bridge  18 . The first bridge  16  is spaced apart from the second bridge  18 . 
     The second portion defines a first side  14 A which faces the first portion  12  and a second side  14 B which faces away from the first portion  12 . 
     The second portion has a first hole  22  extending through the second portion from the first side  14 A to the second side  14 B. The first hole  22  defines a wall  22 A of the first hole. The second portion  14  also includes a second hole  24  extending through the second portion from the first side to the second side, the second hole defining a wall  24 A of the second hole. 
     As will be appreciated the first hole and second hole are both through holes as can be seen from  FIGS. 1, 3 and 4 . The wall of the first hole therefore is a continuous wall defining the first hole. Similarly, the wall of the second hole is a continuous wall defining the second hole. 
     Brake caliper  10  defines a radial direction R (see  FIG. 3 ) and a circumferential direction C. As can be seen from  FIG. 3  the circumferential extent of the first hole  22  is larger than the radial extent of the first hole. The circumferential ends  26  and  27  of the first hole are curved. The radial edges  28 ,  29  of the first hole include straight portions. 
     Similarly, the circumferential ends of the second hole  24  are curved and the radial edges of the second hole  24  include straight portions. 
     The second portion  14  includes a flat portion  30  which surrounds the first hole  22  and the second hole  24 . In use, the brake pad backplate engages the flat portion  30  (as will be further described below). As can be seen from  FIG. 5 , the flat portion  30  is parallel to the plane P rotation of the brake rotor  20 . 
     The first hole  22  is spaced apart from the second hole  24  by a land  32 . Machined into the land  32  is a fixing hole  34 , in this case a threaded hole. The threaded hole is used to secure a brake pad retaining strap  36  as will be further described below. 
     As regards the first portion  12 , this defines the housing  40  which is adapted to receive an actuator mechanism  42  (see  FIG. 5 ). The housing has a first housing side  40 A facing the second portion  14 . The housing has a second housing side  40 B facing away from the second portion  14 . The first housing side  40 A defines a recess  44  for receiving the actuating mechanism  42 . The recess defines a recess opening  46  having a rim  48 . The rim  48  includes threaded holes  49 ,  50  and  51 . The recess  44  includes machined pockets  52  and  53 . 
     The brake caliper  10  is manufactured as follows: 
     A mold (not shown) is provided in order to cast the brake caliper. The mold produces a bare casting (i.e., a casting that has not, at this stage, had any machining operations carried out on it). The bare casting includes the first portion, the second portion, the first bridge and the second bridge. Thus, the first portion, the second portion, the first bridge and the second bridge are cast as a single casting. 
     The mold includes casting cores which define the first hole  22  and the second hole  24  in the bare casting. 
     Various surfaces of the bare casting are machined. Thus, hole  54  in the first portion  12  is drilled by arranging a drill bit to approach the bare casting in the direction of arrow A in order to machine the casting and hence form the hole  54 . Similarly hole  55  can be machined by the drill approaching the casting in the direction of arrow B in order to machine the casting. Hole  56  can be machined by a machine tool approaching the casting in the direction of arrow D. Hole  57  can be machined by a machine tool approaching the casting in the direction of arrow E. Threaded hole  34  can be drilled to a tapping size by a drill approaching the casting in the direction of arrow F and can then be tapped to the correct thread by a tap approaching the hole in the direction of arrow F. As will he appreciated, when machining holes  34 ,  54 ,  55 ,  56  and  57  there is no part of the caliper which obstructs the approach and withdrawal of the machining tool. 
     In prior art calipers machining certain features within and adjacent a housing which receives an actuating mechanism is complicated since the features are obscured by an outer portion of the brake. 
     However, in the present application and as best seen in  FIG. 3 , the machining of threaded holes  50  and  51  and the machining of pockets  52  and  53  is not obscured by the second portion  14  because the second portion  14  includes the first hole  22  and second hole  24  through which the machining tool can pass. Thus, in order to form threaded hole  50 , the hole can first be drilled to a tapping size by a drill hit approaching the hole in the direction of arrow G, the drill bit initially passing through second hole  24  as it approaches rim  48  in order to drill the tapping hole. Once the tapping hole has been drilled the drill can be withdrawn back through the second hole. The tap can then approach the hole  50  in the direction of arrow G passing through the second hole  24  as it approaches and taps threaded hole  50 . The tap can then be withdrawn from hole  50  and then further withdrawn backwards through the second hole  24 . 
     Threaded hole  51  can similarly be drilled and tapped via tools passing through the first hole  22 . 
     As far pocket  53  is concerned, as best seen from  FIG. 4 , this can be machined using an end milling cutter with the cutter passing through the second hole in the direction of arrow H in order to mill the pocket and then being withdrawn back through the second hole  24  once milling of the pocket has been completed. 
     Similarly, a milling cutter can be used to machine pocket  52  by arranging the milling cutter to pass through first hole  22  immediately prior to machining and then being withdrawn back through the first hole after machining. 
     Considering  FIG. 3 , the thread in threaded hole  50  will have an outer diameter. This outer diameter defines an axially projected area, i.e., when viewing  FIG. 3 , which is a view taken along the axis of the brake rotor, the threaded hole  50  defines an area of circular shape. In particular, all of this area can be seen through the second hole  24 , in other words all of the machined parts of threaded hole  50  when projected in an axial direction are encompassed by the second hole  24 . As will be appreciated, the cross-section area of the second hole  24  when viewed in an axial direction is at least as big as the cross section area of the threaded hole  50 . In the present case the cross section area of second hole  24  is larger than the cross-section area of the threaded hole  50 . 
     Similarly, the cross-section area of threaded hole  51  when viewed in the direction of  FIG. 3 , i.e., when viewed in the axial direction of the brake rotor is entirely encompassed by the first hole  22 . 
     As best seen in  FIG. 3 , the machined pocket  53  has a generally U-shaped shape when viewing  FIG. 3 , the U-shape defining an axially projected area of the pocket  53 . It will be appreciated that this axially projected area is entirely encompassed by cross-section of the second. hole  24 . 
     Similarly, pocket  52  has a generally U-shaped cross-section shape defining an axially projected area which axially projected area is entirely encompassed by the cross-section of the first hole  22 . 
     As described above, first side  14 A of the second portion has a flat portion  30 . This can be machined by a milling cutter attached to a tool positioned in either above the caliper when viewing  FIG. 1  or positioned below the caliper when viewing  FIG. 1 . 
       FIG. 6  shows a brake pad  60  having a brake pad backplate  61  and friction material  62 . The brake pad backplate includes first projection  63  and second projection  64 . When assembled into the brake caliper  10  the first projection  63  is received in the first hole  22  and the second projection  64  is received in the second hole  24 . The first projection  63  includes a rim  63 A and the second projection  64  includes a rim  64 A. A part of the rim  63 A engages part of the wall  22 A of the first hole and a part of the rim  64 A engages a part of the wall  24 A of the second hole. As will be appreciated from  FIG. 5 , because rims  63 A and  64 A are received in holes  22  and  24  then this prevents the brake pad  60  moving either up or down in the radial direction R when viewing  FIG. 3  and also prevents the brake pad  60  moving right or left in a circumferential direction C when viewing  FIG. 3 . Furthermore, since the first projection  63  is spaced apart from the second projection  64  then the brake pad cannot twist, i.e., the spacing apart of the first and second projections prevents, for example, the first projection moving radially upwards when viewing  FIG. 3  whilst the second projection moves radially downwards when viewing  FIG. 3  (and vice versa). 
     With reference to  FIGS. 7 to 9  there is shown a second embodiment of a brake caliper  110  according to the present invention wherein features which perform substantially the same function as those of brake caliper  10  are labelled  100  greater. As will be appreciated, machined pocket  152  is machined in a similar manner to pocket  152 , i.e., machined pocket  152  is machined by the tool passing through the first hole  22  as it approaches the pocket and the tool being withdrawn through the first hole  122  once the machining of pocket  152  has been completed (see especially  FIG. 9 ). 
     In this case the recess  144  includes a machined surface  166 , in this case a flat machined surface. As best seen from  FIGS. 7 and 9 , the machined surface has an overall height J. The machined surface is parallel to the axis of rotation of the brake rotor, in other words it is perpendicular to the plane of rotation of the brake rotor. This machined surface can be machined using a milling cutter which can be moved into position by passing it through the first hole  122  prior to machining and once the machined surface  166  has been completed the milling cutter can be withdrawn back through the first hole  122 . As will be appreciated from  FIG. 9 , the machined surface  166  defines an axially projected line  167  having height J and as best seen in  FIG. 9 , all of the axially projected line  167  is encompassed by the hole  122 . 
       FIG. 10  shows a bearing  70  having a part cylindrical bearing surface  71  integrally formed with a circular boss  72 . The circular boss  72  has a diameter which is similar to the diameter of the machined pocket  152 . As can be seen from  FIG. 8 , once the pocket  152  has been machined, the bearing  70  can be assembled into that pocket, in particular the circular boss  72  can be fitted into pocket  152 . This enables the part cylindrical bearing surface  71  to be provided inside the recess  144 . As can be seen from  FIG. 8 , a further bearing  70  can be fitted in a pocket the equivalent of pocket  53  of caliper  10  to provide a second part cylindrical bearing surface. As will be appreciated, with regard to braking caliper  10 , a bearing  70  can be fitted into pocket  52  to provide the bearing surface and a further bearing  70  can be fitted into pocket  53  to provide further bearing surface. 
     The cylindrical bearing surface  71  and the circular boss  72  of bearing  70  are integrally formed.  FIGS. 11 and 12  show a bearing  270  wherein a circular boss  272  is formed separately from a cylindrical bearing surface  271 . The circular boss  272  includes a concave recess  273  to receive the cylindrical bearing surface  271 . 
     While exemplary embodiments are described above, it is not intended that these embodiments describe all possible forms of the invention. Rather, the words used in the specification are words of description rather than limitation, and it is understood that various changes may be made without departing from the spirit and scope of the invention. Additionally, the features of various implementing embodiments may be combined to form further embodiments of the invention.