Patent Publication Number: US-2007119665-A1

Title: Outer pad abutment design for frame type calipers

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS  
      This application relates to U.S. patent application Ser. No. ______ filed on ______ titled Support Bracket For An Internally Abutted Brake Pad And A Hanging Brake Pad, Attorney Docket No. 2448-000027. The above disclosed application is hereby incorporated by reference as if fully set forth herein. 
    
    
     FIELD  
      The present teachings relate to a support bracket configured to receive both a hanging brake pad and an internally abutted brake pad and more specifically to an outside abutment brake pad design and method for same.  
     BACKGROUND  
      In one example and with reference to  FIG. 1 , a caliper assembly  1  may have a support bracket  2 , which may be configured to receive a pair of internally abutted brake pads  3 . The support bracket  2  having the pair of internally abutted brake pads  3  tends to deflect relatively less under braking loads than a support bracket having a pair of rails and the associated hanging brake pads. The support bracket  2  may include an outer beam tension member  4 , to reduce the deflection under the braking load. The support brackets  2  configured to receive the pair of internally abutted brake pads  3  are, however, relatively larger and heavier than the support bracket with the pair of rails and associated hanging pads.  
      Typically, the support bracket with a pair of hanging rails has a bridge portion that extends over the rotor. The bridge portion may require further machining (e.g., milling, cutting, etc.) In addition, a finger may be machined into the rails that may require multi-step process to form the relatively small structure. Moreover, the center of gravity of the friction material on the outer hanging pad to be misaligned with respect to a centerline of a piston in the caliper assembly.  
     SUMMARY  
      The present teachings generally include a brake assembly including a caliper body that clamps brake pads against a rotor. The brake assembly includes a support bracket defining a planar portion, a bridging portion and a pair of rails. The bridging portion extends in a generally perpendicular direction from the planar portion. The pair of rails extends from the bridging portion. Each of the rails has an inside face, an outside face, a top face, a bottom face and an outboard face. The inside face, the outside face, the top face and the bottom face are aligned in generally a perpendicular direction relative to the planar portion. A first dimension defining a length between the inside face and the outside face near the top face is less than a second dimension defining a length between the inside face and the outside near the bottom face.  
      Further areas of applicability of the present teachings will become apparent from the detailed description and the claims provided hereinafter. It should be understood that the specific examples in the detailed description, while indicating the various embodiments of the teachings, are intended for purposes of illustration only and are not intended to limit the scope of the present teachings. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
      The various embodiments of the present teachings will become more fully understood from the detailed description, the appended claims, and the accompanying drawings, wherein:  
       FIG. 1  is a prior art perspective view of a brake caliper assembly including a support bracket configured to internally abut a pair of brake pads and having an outer beam tension member;  
       FIGS. 2 and 3  are perspective views of a disc brake assembly showing a rotor received by a support bracket having an abutted brake pad and a hanging brake pad constructed in accordance with the present teachings;  
       FIG. 4  is a bottom view of the disc brake assembly of  FIGS. 2 and 3 ;  
       FIG. 5  is a cross-sectional view of the disc brake assembly of  FIG. 4  showing the caliper body in an unclamped or open position in accordance with the present teachings;  
       FIG. 6  is similar to  FIG. 5  and shows the caliper in a clamped position;  
       FIG. 7A  is a perspective view of the outboard side of the support bracket of  FIGS. 2 and 3  in accordance with the present teachings;  
       FIG. 7B  is a perspective view of the inboard side of the support bracket of  FIG. 7A ;  
       FIG. 8A  is similar to  FIG. 7A  and shows a hanging brake pad connected to the support bracket in accordance with the present teachings;  
       FIG. 8B  is similar to  FIG. 7B  and shows the internally abutted brake pad held within the support bracket;  
       FIG. 9A  is a perspective view of the internally abutted brake pad of  FIG. 8B ;  
       FIG. 9B  is a perspective view of the hanging pad of  FIG. 8A ;  
       FIG. 10  is a perspective view of the hanging brake pad and support bracket of  FIG. 8A  showing removal of the hanging brake pad without the need for removal of the support bracket or the rotor and in addition removal of the rotor without the need to remove the support bracket from a portion of the vehicle in accordance with the present teachings;  
       FIGS. 11 and 12  are perspective views of an alternative embodiment showing a portion of an inside face of the hanging rail inclined at about forty-five degrees and brake pad with a rail channel having a complementary shape in accordance with the present teachings;  
       FIGS. 13 and 14  are perspective views of an alternative embodiment showing a rounded portion of an inside face of the hanging rail and brake pad with a rail channel having a complementary shape in accordance with the present teachings;  
       FIGS. 15 and 16  are perspective views of an alternative embodiment showing a portion of an outside face of the hanging rail inclined at about forty-five degrees and brake pad with rail channel having a complementary shape in accordance with the present teachings; and  
       FIG. 17  is a perspective view of an exemplary cutting tool forming the hanging rails of the support bracket in accordance with the present teachings. 
    
    
     DETAILED DESCRIPTION OF THE VARIOUS EMBODIMENTS  
      The following description of the various embodiments is merely exemplary in nature and is in no way intended to limit the teachings, their application, or uses.  
      The present teachings generally include a disc brake system  10 . While the present teachings are generally described and illustrated with reference to a vehicle and an exemplary associated suspension and drive train, the present teachings remain applicable in various applications to aid in slowing of rotating motion. With reference to  FIGS. 2 and 3 , the disc brake assembly  10  includes a caliper body  12 , a support bracket  14 , an outboard brake pad  16  and an inboard brake pad  18 . In one example, the support bracket  14  is configured to receive a hanging brake pad  20  and an internally abutted brake pad  22 . In this regard, the outboard brake pad  16  may define the hanging brake pad  20 , while the inboard brake pad  18  may define the internally abutted brake pad  22 . In other examples, the position of the brake pads may be reversed. The caliper body  12  may connect to the support bracket  14  and be moveable relative thereto when clamping the brake pads  16 ,  18  against a rotor  24  to slow the motion of a vehicle (not shown).  
      The support bracket  14  may define hanging rails  26  ( FIGS. 7A and 7B ) and an aperture  28 . The aperture  28  may serve as an internal abutment portion for the internally abutted brake pad  22 . The hanging rails  26  may include a front rail  26   a  and rear rail  26   b  from which the hanging brake pad  20  may be coupled. With regard to abutting the brake pad  22 , the aperture  28  may define a front abutment portion  30  and a rear abutment portion  32  that receive (i.e. abut) the internally abutted brake pad  22 .  
      The support bracket  14  may also define two mounting holes  34 . The mounting holes  34  may facilitate coupling the support bracket  14  locations on the vehicle (not shown) using various suitable methods. The support bracket  14  may further define two mounting bosses  36  in which an aperture  38  ( FIG. 7B ) is formed. A fastener  40  may couple the caliper body  12  to the support bracket  14  via the aperture  38  on the mounting boss  36  and further allow the caliper body  12  to move relative to the support bracket  14  when clamping against the rotor  24 . In this regard, the support bracket  14  remains fixed with the vehicle and the caliper body  12  moves relative to the rotor  24 .  
      In one example and with reference to  FIGS. 7A and 7B , the support bracket  14  is a single piece of material, i.e., monolithic. For example, the support bracket  14  may be made from a single casting. The support bracket  14  may define a bridging portion  42  that extends over the rotor  24 . The bridging portion  42  may extend in a generally perpendicular direction from a generally planar portion  44  of the support bracket  14 . The hanging rails  26  may extend from the bridging portion  42 . In this regard, the planar portion  44  may define the aperture  28  that receives (i.e., abuts) the internally abutted brake pad  22 , while the hanging rails  26  can hold the hanging brake pad  20 .  
      With regard to the hanging rails  26 , the front rail  26   a  includes a protrusion  46  that may face the rear rail  26   b . The rear rail  26   b  includes a protrusion  48  that may face the front rail  26   a . With reference to  FIGS. 9A and 9B , the brake pads  20 ,  22  include a backing member  50  and a friction material  52 . With reference to  FIG. 8B  and  FIG. 9B , the backing member  50  defines a front rail channel  58  and a rear rail channel  60 . The rail channels  58 ,  60  further define respective grooves  62 . In one example, the grooves  62  may be formed on inside walls of the rail channels  58 ,  60 . When the hanging brake pad  20  is received by (and hangs from) the rails  26 , the protrusions  46 ,  48  are received by the grooves  62  and thus hold the brake pad  20  to the rails  26 . When the caliper body  12  clamps the brake pads  20 ,  22  against the rotor  24 , the hanging brake pad  20  travels along the rails  26 , thus contacting the rotor  24  with the friction material  52  to slow the vehicle.  
      With reference to  FIGS. 7B and 8B , the support bracket  14  defines the aperture  28  that receives and abuts the internally abutted brake pad  22 . The front abutment portion  30  may define a front channel  66  and the rear abutment portion  32  may define a rear channel  68 . The backing member  50  of the internally abutted brake pad  22  may define a pair of flanges  70  ( FIG. 9A ) that is received in the front channel  66  and the rear channel  68 , respectively. More specifically, a front flange  70   a  ( FIG. 9A ) may abut the front channel  66  formed in the front abutment portion  30  during a braking load, i.e., when the vehicle is slowed in a forward direction. A rear flange  70   b  ( FIG. 9A ) may similarly abut the rear channel  68  formed in the rear abutment portion  32  during an opposite braking load i.e., when the, vehicle is slowed in a rearward direction. It will be appreciated that the internally abutted brake pad  22  is held within the aperture  28  while no braking load is supplied.  
      In one example and with reference to  8 A and  9 B, a front rail clip  72  may be disposed between the front rail  26   a  and the front rail channel  58 . A rear rail clip  74  may be disposed between the rear rail  26   b  and the rear rail channel  60 . With reference to  FIGS. 8B and 9A , a front abutment clip  76  may be disposed between the front abutment portion  30  and a front side  78  of the internally abutted brake pad  22 . The front side  78  of the brake pad  22  may further define the aforementioned front flange  70   a . A rear abutment clip  80  may be disposed between the rear abutment portion  32  and a rear side  82  of the internally abutted brake pad  22 . The rear side  82  of the brake pad  22  may define the aforementioned rear flange  70   b.    
      It may be shown that one or more of the clips  72 ,  74 ,  76 ,  80  may reduce the friction between the above-mentioned portions and structures of the support bracket  14  and the pads  20 ,  22  between which the clips  72 ,  74 ,  76 ,  80  are respectively disposed relative to contact therebetween without the clips  72 ,  74 ,  76 ,  80 . Moreover, it may be shown that the clips  72 ,  74 ,  76 ,  80  position and provide tension between the internally abutted brake pad  22 , the aperture  28 , the rails  26  and rail channels  66 ,  68 . The tension between the pads  20 ,  22  and the support bracket  14  may be shown to reduce noise, vibration or harshness in the disc brake assembly  10 .  
      With reference to  FIGS. 2, 3  and  4 , the caliper body  12  includes a first piston  84 , a second piston  86 , an inboard contact surface  88  and an outboard contact surface  90 . The pistons  84 ,  86  may be formed on (and behind) the inboard contact surface  88 . The outboard contact surface  90  is about opposite to the inboard contact surface  88 , i.e., on opposite sides of the rotor  24 . A face  92  of each piston  84 ,  86  contacts the backing member  50  of the inboard brake pad  18  (illustrated as the internally abutted brake pad  22 ).  
      An inboard shim  94  may be placed between the inboard brake pad  18  and the faces  92  of the pistons  84 ,  86  respectively. It will be appreciated when the pistons  84 ,  86  are fully retracted (i.e., flush or recessed with the caliper body  12 ), the inboard shim  94  ( FIGS. 5 and 6 ) may contact the outboard contact surface  90 . The outboard contact surface  90  may abut the backing member  50  of the outboard brake pad  16  (illustrated as the hanging pad  20 ). An outboard shim  96  ( FIGS. 5 and 6 ) may be placed between the outboard brake pad  16  and the outboard contact surface  90  of the caliper body  12 . The caliper body  12  may also include a suitable hydraulic valve that may allow for addition, removal and/or maintenance of a hydraulic fluid within the first and second pistons  84 ,  86 .  
      In operation and with reference to  FIGS. 5 and 6 , the pistons  84 ,  86  may be extended and retracted by manipulating the hydraulic fluid pressure in the caliper body  12 . By increasing the hydraulic fluid pressure to the pistons  84 ,  86 , the pistons  84 ,  86  extend out of the caliper body  12  and define an extended or clamping position  98 . By reducing the hydraulic pressure to the pistons  84 ,  86 , the pistons  84 ,  86  retreat into the caliper body  12  and define an unclamped or retracted position  100 . In the clamped position  98 , the faces  92  of the respective pistons  84 ,  86  urge the inboard brake pad  18  toward an inboard face  102  of the rotor  24 . The caliper body  12  also moves relative to the support bracket  14  and the rotor  24  and therefore urges the outboard brake pad  16  toward an outboard face  104  of the rotor  24 . The friction material  52  on the inboard and the outboard brake pads  16 ,  18  contact the faces  102 ,  104  of the rotor  24 . The pistons  84 ,  86  may continue to urge the pads  16 ,  18  against the rotor  24 , thereby clamping the rotor  24  and reducing its rotational velocity to thereby slow the vehicle. By contacting the rotor  24 , the friction material  52  on the brake pads  20 ,  22  wear due to the heat and abrasion while engaging the rotor  24 .  
      In one example and with reference to  FIG. 10 , the hanging brake pad  20  may be removed from the hanging rails  26  ( 26 A and  26 B) without removal of the rotor  24  or the support bracket  14  from an applicable portion (e.g. a bracket  106 ) of the vehicle. In a further example, the rotor  24  may be removed from an applicable portion of the vehicle (e.g., a drive shaft flange) without the need for removing the support bracket  14  from the bracket  106 . More specifically, the caliper body  12  is removed from the support bracket  14  by, for example, removing the fasteners  40  from the mounting bores  36  ( FIG. 3 ). With the caliper body  12  removed from the support bracket  14 , the hanging brake pad  20  may be slid off the hanging rails  26 . Additionally, the rotor  24  may be removed without the need to uncouple the support bracket  14 . In this regard, the hanging rails  26  are configured so that the rotor  24  may decouple from (i.e., pulled away) the driveshaft flange. Specifically, the rotor  24  is pulled laterally away from the vehicle, e.g., along the rotor&#39;s installed axis of rotation (i.e., an axis upon which the rotor  24  spins while installed on the vehicle in a normal fashion).  
      With reference to  FIGS. 11, 13  and  15 , the rails  26  may each have a top face  108 , a bottom face  110 , an inside face  112  and an outside face  114 . An outboard face  116  is formed at a terminus of the hanging rail  26  and thus connects with the aforesaid top, bottom, inside and outside faces  108 ,  110 ,  112 ,  114 . The inside face  112 , the outside face  114 , the top face  108  and the bottom face  110  are aligned generally perpendicular to the planar portion  44  of the support bracket  114 . In one example and with reference to  FIG. 13 , a dimension  118  defining a first length between the inside face  112  and the outside face  114  near the top face  108  of the hanging rail  26  is less than a dimension  120  defining a second length between the inside face  112  and the outside face  114  near the bottom face  110 .  
      In one example and with reference to  FIG. 11 , each of the hanging rails  26  may have at least a portion of the inside face  112  inclined about forty-five degrees (or other suitable angle) relative to the outside face  114 . More specifically, a portion  112   a  of the inside face  112  near the top face  108  may be inclined at about a forty-five degree angle (or other suitable angle), while the remaining portion  112   b  of the inside face  112  near the bottom face may be straight and/or parallel to the outside face  114 . In one example, the bottom face  110  may be entirely flat. In other examples, the bottom face  110  may also define two or more regions. Each region may be inclined relative to the other region thus forming, for example, an acute angle between the regions. One region  122  (i.e., a planar portion of the bottom face  110 ) may be inclined to abut a portion of the backing member  50  of the brake pad  18 . In this regard, the force generated during braking causes the pad  18  to move toward and abut the hanging rail  26 .  
      With reference to  FIG. 12 , the rear rail channel  60  and the front rail channel  58  may be configured to compliment the shapes of the hanging rails  26 . More specifically, the grooves  62  formed in the rail channels  58 ,  60  may have a complimentary shape to the portion  112   a  of the inside face  112  that is inclined about forty-five degrees. In addition, a ramped surface  124  may be about parallel to the region  122  formed on the bottom face  110  of the hanging rail  26 . The front and/or rear rail channels  58 ,  60  may also corners that have an over-sized radius corners to accept edges of the hanging rails  26  especially during motion of the brake pad  18  during braking.  
      With reference to  FIG. 13 , the inside face  112  of each of the hanging rails  26  may have an arcuate portion  126  that runs between the top face  108  and the bottom face  110 . More specifically, the arcuate portion  126  may be formed on or along the inside face  112  and/or the top face  108  of the hanging rail  26 . The bottom face  110  of the hanging rail may (or may not) be configured similar to the hanging rail  26  illustrated in  FIG. 11 . In the various examples, the backing member  50  ( FIG. 14 ) may abut the hanging rail at one or more of faces  108 ,  110 ,  112 ,  114  depending on the braking load.  
      With reference to  FIG. 14 , the front rail channel  58  and the rear rail channel  60  may be configured to receive the hanging rails  26  as illustrated in  FIG. 13 . More specifically, the grooves  62  formed in the rail channels  58 ,  60  may have complimentary shapes to at least the rounded or arcuate portion  126  of the inside face  112 .  
      With reference to  FIG. 15 , the outside face  114  may include an inclined portion  114   a  relative to the inside face  112 . The inclined portion  114   a  may be at an angle of about forty-five degrees such that an inclined portion  114   a  (e.g., upper portion) of the outside face  114  may be inclined at about forty-five degrees relative to the bottom portion  114   b  which is straight relative to the inside face  112 . As such, the bottom portion  114   b  of the outside face  114  is about parallel to the inside face  112 . The bottom face  110  of the hanging rail  26  may or may not include a configuration similar to the hanging rail  26  illustrated in  FIG. 11 .  
      With reference to  FIG. 16 , the front rail channel  58  and the rear rail channel  60  may be configured to compliment the hanging rails  26  as illustrated in  FIG. 15 . More specifically, the groove  62  formed in the rail channels  58 ,  60  may compliment the upper portion on  114   b  that is inclined. It will be appreciated that the front rail  26   a  and the rear rail  26   b  may be configured identically or may be configured dissimilarly. As such, the respective rail channels  58 ,  60  formed in backing member  50  of the hanging pad  18  may (or may not) have complimentary rail channel  58  or  60  configurations.  
      With reference to  FIGS. 11 through 16 , the faces  108 - 116  of the hanging rail  26  and the configuration of the rail channels  58 ,  60  are such that the faces  108 - 116  may be connected with rounded (beveled and/or chamfered) corners. Moreover, the bottom face  110  may provide sufficient clearance relative to the rotor  24  so as to permit removal of rotor  24  along its installed axis of rotation, as illustrated in  FIG. 10 .  
      With reference to  FIG. 17 , a cutting tool  200  (e.g. a mill or other suitable cutting machine) can trim the hanging rail  26  in a single pass to produce the one or more rounded edges on the hanging rail  26 . In one example, only the hanging rails  26  require cutting by the cutting tool  200 . Specifically, the bridging portion  42  need not be cut or trimmed especially a surface  202  which is adjacent to (i.e., extends over) the rotor  24 . The surface  202  may be left as-cast (i.e., no additional finish steps). It will be shown that need to only cut the hanging rails  26  and thus not cut (trim or grind) the bridging portion  42  may save time and costs.  
      With reference to  FIGS. 11-16 , it will be shown that the various aforementioned configurations of the rail channels  58 ,  60  may allow positioning of the friction material  52  relative to the backing member  50  such that a center of gravity of the friction material  52  is closer to a center line of the piston.  
      Those skilled in the art can now appreciate from the foregoing description that the broad teachings may be implemented in a variety of forms. Therefore, while the present teachings have been described in connection with the specific examples thereof, the true scope of the present teachings should not be so limited because other modifications will become apparent upon a study of the drawings, the specification, and the following claims.