Abstract:
A brake assembly includes a brake pad, a bracket supporting the brake pad and having a first portion, a second portion spaced apart from the first portion, and a linkage interconnecting the first and second portions. The linkage is configured to transfer tensile loads between the first and second portion, but is characterized by the absence of any bending modes. The absence of bending modes prevents excitation of the linkage, thereby reducing sound generated during application of the brake assembly.

Description:
CROSS REFERENCE TO RELATED APPLICATION 
       [0001]    This application is a divisional application of U.S. patent application Ser. No. 12/794,815, filed Jun. 7, 2010, and which is hereby incorporated by reference in its entirety. 
     
    
     TECHNICAL FIELD 
       [0002]    This invention relates to vehicle brake assemblies. 
       BACKGROUND OF THE INVENTION 
       [0003]    A disc brake assembly typically includes a rotor and a caliper. The rotor is connectable to a hub of a rotatable axle. The caliper includes a mutually opposed pair of brake pads supported by a bracket. Each of the brake pads overlies a respective rotor braking surface. Normally, the caliper keeps the brake pads separated from the braking surfaces of the rotor. The braking system is activated by moving the pads into contact with the braking surfaces of the rotor; frictional interaction between the braking surfaces and the pads reduces or prevents rotation of the rotor relative to the caliper. 
         [0004]    Brake squeal may be the result of modal excitations of the disc brake rotor (composed usually of cast iron) and the disc brake caliper by the frictional interaction of the brake pads. Countermeasures to reduce low-frequency brake squeal include increasing the stiffness of the caliper bracket by increasing the cross-sectional area of the tie-bars, and casting in or mechanically attaching a mass to the caliper bracket, wherein the mass acts as a vibration damper and/or changes the dynamic response of the caliper bracket. 
       SUMMARY 
       [0005]    A brake assembly includes a brake pad, a bracket supporting the brake pad and having a first portion, a second portion spaced apart from the first portion, and a linkage interconnecting the first and second portions. The linkage is configured to transfer tensile loads between the first and second portion, but is characterized by the absence of any bending modes. The absence of bending modes prevents excitation of the linkage, thereby reducing sound generated during application of the brake assembly. 
         [0006]    The above features and advantages and other features and advantages of the present invention are readily apparent from the following detailed description of the best modes for carrying out the invention when taken in connection with the accompanying drawings. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0007]      FIG. 1  is a schematic, perspective view of a brake assembly having a caliper assembly with a bracket; 
           [0008]      FIG. 2  is a schematic, perspective view of the bracket of  FIG. 1 ; 
           [0009]      FIG. 3  is a schematic, top view of the bracket of  FIG. 1 ; 
           [0010]      FIG. 4  is a joint for use with the bracket of  FIG. 1 ; 
           [0011]      FIG. 5  is another joint for use with the bracket of  FIG. 1 ; and 
           [0012]      FIG. 6  is an alternative bracket configuration for use with the brake assembly of  FIG. 1 . 
       
    
    
     DETAILED DESCRIPTION 
       [0013]    Referring to  FIG. 1 , a brake assembly  10  includes a caliper assembly  12  and a rotor  14 . The caliper assembly  12  includes first and second brake pads  16 ,  18 , which are supported by a bracket  20 . Referring to  FIGS. 1 and 2 , the bracket  20  is generally U-shaped, and includes a first portion  22 , a second portion  26  spaced apart from the first portion  22 , a first tie-bar linkage  30 , and a second tie-bar linkage  34 . The linkages  30 ,  34  interconnect the first and second portions  22 ,  26 . 
         [0014]    The rotor  14  in the embodiment depicted includes an inner portion  38  that is generally ring-shaped. The inner portion  38  defines a center hole  42  at which the rotor  14  is mountable to an axle (not shown), as understood by those skilled in the art. The inner diameter of the rotor  14  at the hole  42  includes splines as shown for engagement with complementary splines on the axle. The inner portion  38  also has a plurality of threaded studs  46  protruding therefrom. As understood by those skilled in the art, a wheel (not shown) is mountable to the rotor  14  at the studs  46  such that the wheel and rotor  14  rotate as a unit. 
         [0015]    The rotor  14  also includes an outer portion  50 , which is generally ring-shaped and which concentrically surrounds the inner portion  38 . The outer portion  50  includes two opposing rotor cheeks  54 ,  55  having ventilation vanes  58  therebetween. Each rotor cheek  54 ,  55  defines a respective braking surface  62 ,  63 . 
         [0016]    Each of the brake pads  16 ,  18  overlies a respective rotor cheek braking surface  62 ,  63 , i.e., the pads  16 ,  18  are positioned such that portions of the rotor cheeks  54 ,  55  are therebetween. The pads  16 ,  18  are selectively movable between engaged and disengaged positions, as understood by those skilled in the art. When the pads  16 ,  18  are in their disengaged positions, they do not contact the braking surfaces  62 ,  63 , and therefore do not cause any resistance to the rotation of the rotor  14  and the wheel attached thereto. When the pads  16 ,  18  are in their engaged positions, each of the pads  16 ,  18  contacts a respective braking surface  62 ,  63 , thereby resisting rotation of the rotor  14  and the wheel attached thereto. The pads  16 ,  18  may be moved to their engaged positions through hydraulic actuation, electronic actuation, etc., as understood by those skilled in the art. The rate of braking is dependent upon the pressure of the brake pads  16 ,  18  against the braking surfaces  62 ,  63 . 
         [0017]    The linkages  30 ,  34  are configured to support tensile loads between the first and second portions  22 ,  26 , but will not support a bending mode. More specifically, and with reference to  FIGS. 2 and 3 , linkage  30  includes first, second, third, and fourth generally rigid links  66 ,  67 ,  68 ,  69 . The first link  66  is substantially rigidly connected to the first portion  22 ; the fourth link  69  is substantially rigidly connected to the second portion  26 . 
         [0018]    The linkage  30  also includes one or more joints. More specifically, in the embodiment depicted, the linkage  30  includes joints  70 ,  71 , and  72 . Joint  70  operatively connects link  67  to link  66 ; joint  71  operatively connects link  67  to link  68 ; and joint  72  operatively connects link  68  to link  69 . 
         [0019]    Similarly, linkage  34  includes first, second, third, and fourth generally rigid links  74 ,  75 ,  76 ,  77 . The first link  74  is substantially rigidly connected to the first portion  22 ; the fourth link  77  is substantially rigidly connected to the second portion  26 . 
         [0020]    The linkage  34  also includes one or more joints. More specifically, in the embodiment depicted, the linkage  34  includes joints  78 ,  79 , and  80 . Joint  78  operatively connects link  75  to link  74 ; joint  79  operatively connects link  75  to link  76 ; and joint  80  operatively connects link  76  to link  77 . 
         [0021]      FIG. 4  schematically depicts a joint  82  interconnecting a first link  86  and a second link  87 . Joint  82  may be representative of joints  70 ,  71 ,  72  and joints  78 ,  79 ,  80 , and links  86 ,  87  may be representative of links  66 ,  67 ,  68 ,  69  and links  74 ,  75 ,  76 ,  77 . Referring to  FIG. 4 , links  86  and  87  are formed from a single piece of material in which a void  90  has been formed to separate the single piece of material into the two links  86 ,  87 . The void  90  in the embodiment depicted is configured such that link  86  defines a first hook portion  94  and link  87  defines a second hook portion  95  that interlock with each other to support a tensile load between links  86  and  87 , while preventing bending modes. 
         [0022]      FIG. 5  schematically depicts another joint  98  interconnecting a first link  102  and a second link  103 . Joint  98  may be representative of joints  70 ,  71 ,  72  and joints  78 ,  79 ,  80 , and links  102 ,  103  may be representative of links  66 ,  67 ,  68 ,  69  and links  74 ,  75 ,  76 ,  77 . Joint  98  is a hinge about which link  103  is rotatable with respect to link  102 . More specifically, in the embodiment depicted, link  102  defines a hole  106 . Link  103  defines a hole  107 . Holes  106  and  107  are aligned with one another, and a hinge pin  110  extends therethrough. Hinge pin  110  limits movement of link  103  with respect to  102  to rotation. Accordingly, when the links  102 ,  103  are at a 180 degree angle with respect to one another, the joint  98  supports a tensile load, but will not support a moment. Accordingly, the linkage formed by links  102 ,  103  does not have any bending modes. 
         [0023]    Referring to  FIG. 6 , wherein like reference numbers refer to like components from  FIGS. 1-5 , an alternative bracket  120  for use in the caliper assembly  12  of  FIG. 1  is schematically depicted. Bracket  120  includes first and second portions  22 ,  26  interconnected by linkages  130 ,  134 . Linkages  130 ,  134  are configured to transmit tensile loads between the first and second portions  22 ,  26 . Linkage  130  is a single piece of substantially rigid material in the embodiment depicted. Linkage  134  is a flexible member and, more particularly, a segment of cable in the embodiment depicted. Accordingly, linkage  34  is unable to support a compressive load or a moment, and is thus characterized by the absence of any bending modes. 
         [0024]    Brake squeal is the result of excitation of either the brake rotor  14  or the caliper bracket  20 ,  120 . The caliper bracket modes that typically generate brake squeal are the bending modes of the caliper linkages. Accordingly, the brackets  20 ,  120  may result in reduced brake squeal because the linkages  30 ,  34 ,  134  do not have any bending modes. 
         [0025]    While the best modes for carrying out the invention have been described in detail, those familiar with the art to which this invention relates will recognize various alternative designs and embodiments for practicing the invention within the scope of the appended claims.