Abstract:
A wheel hub and brake rotor assembly is disclosed which is resistant to corrosion via cathodic protection. One or more sacrificial anodes may be mounted on the hub and/or the rotor.

Description:
CROSS-REFERENCE TO RELATED APPLICATION 
       [0001]    This application claims priority from U.S. Provisional Application Ser. No. 62/036,347, filed Aug. 12, 2014, the disclosure of which is incorporated herein by reference. 
     
    
     BACKGROUND OF THE INVENTION 
       [0002]    1. Technical Field 
         [0003]    The present invention relates generally to a hub and brake rotor assembly such as used for a wheel assembly of a wheeled vehicle. More particularly, the invention relates to corrosion resistance of such an assembly by use of cathodic protection. 
         [0004]    2. Background Information 
         [0005]    Corrosion of hub and brake rotor assemblies is well known, and is especially problematic in coastal areas due to the salt water. Coatings of various sorts have been applied to hubs and rotors in an attempt to prevent or minimize such corrosion. While such coatings have been used with various degrees of success, there is still a need in the art for better protection. The present invention addresses this and other problems in the art. 
       SUMMARY 
       [0006]    In one aspect, the invention may provide an apparatus comprising: at least one of a wheel hub and a brake rotor; and a first sacrificial anode secured to the at least one of the wheel hub and brake rotor. 
         [0007]    In another aspect, the invention may provide a method comprising the steps of: providing an assembly comprising at least one of a wheel hub and a brake rotor; and securing a sacrificial anode to the at least one of the wheel hub and brake rotor. 
     
    
     
       BRIEF DESCRIPTION OF THE SEVERAL VIEWS OF THE DRAWINGS 
         [0008]    A sample embodiment of the invention is set forth in the following description, is shown in the drawings and is particularly and distinctly pointed out and set forth in the appended claims. 
           [0009]      FIG. 1  is an outboard end elevation view of the hub and brake rotor assembly. 
           [0010]      FIG. 2  is a sectional view taken on line  2 - 2  of  FIG. 1 . 
           [0011]      FIG. 3  is a sectional view taken on line  3 - 3  of  FIG. 1 . 
           [0012]      FIG. 4  is a sectional view taken on line  4 - 4  of  FIG. 1 . 
           [0013]      FIG. 5  is a perspective view of one of the sacrificial anodes. 
           [0014]      FIG. 6  is an elevation view of the anode of  FIG. 5 . 
       
    
    
       [0015]    Similar numbers refer to similar parts throughout the drawings. 
       DETAILED DESCRIPTION 
       [0016]      FIGS. 1-3  show a hub and brake rotor assembly  1  which may include a hub  2 , a brake rotor  4 , a plurality of wheel bolts or studs  6 , a bearing protector assembly  8  having a bearing protector or sleeve  10  and dust cap  12 , a plurality of galvanic or sacrificial anodes  14 A-D,  15 A-D and  16 A-B. Sleeve  10  may also serve as a galvanic or sacrificial anode. Hub  2  and brake rotor  4  are formed of metal, typically cast iron or ductile iron, and less commonly a steel which may be a stainless steel. The figures show hub  2  and rotor  4  as individual pieces which are secured to one another by bolts  6 . However, the figures also may represent that hub  2  and rotor  4  are formed as an integral hub and rotor which is a single unitary piece. Wheel bolts  6  are formed of a suitable metal such as steel, as known in the art. Sleeve  10  when serving as a sacrificial anode, and sacrificial anodes  14 ,  15  and  16  are formed of a suitable metal which will serve as a sacrificial anode for hub  2  and/or rotor  4 . These anodes are typically formed of aluminum or an aluminum base alloy, zinc or a zinc base alloy, or magnesium or a magnesium base alloy. One example of a suitable aluminum alloy for use as a sacrificial anode is military specification MIL-A-24779, which is roughly about 95% aluminum and about 5% zinc plus or minus about 1% or 2% of either element. This is but one example, and many other alloys may be suitable for the present purpose. 
         [0017]    Assembly  1  has an inboard end  18  and an outboard end  20  and has a central axis X which extends from inboard end  18  to outboard end  20  and about which assembly  1  is rotatable such as it is when a wheel assembly (tire and rim) is mounted thereon and assembly  1  is mounted on a spindle assembly of a wheeled vehicle. Assembly  1  is essentially radially symmetrical about axis X. Assembly  1  has an axial direction extending generally in the direction of axis X. Assembly  1  has an inboard direction (Arrow A) which is generally in the axial direction toward the inboard end  18  and away from outboard end  20 , and an outboard direction (Arrow B) which is generally in the axial direction toward the outboard end  20  and away from inboard end  18 . 
         [0018]    Hub  2  includes a generally cylindrical hub sleeve  22  and an annular wheel flange  24  which is rigidly secured to and extends radially outwardly from hub sleeve  22  (away from axis X). Flange  24  defines a plurality of wheel bolt holes  26  for receiving therein bolts  6  respectively. Flange  24  has inboard and outboard surfaces  25  and  27  which face away from one another and respectively are inboard-facing and outboard-facing surfaces. Each of holes  26  extends from inboard surface  25  to outboard surface  27 . In the exemplary embodiment, there are five holes  26  which are equally circumferentially spaced from one another and equidistant from axis X, for receiving the corresponding five bolts  6  therein. Flange  24  may define a plurality of anode receiving holes  31  which may be threaded holes in which anodes  16 A and  16 B are respectively received and mounted on flange  24  of hub  2 . Holes  31  typically extend in the outboard direction from inboard surface  25  and may extend to outboard surface  27 . A pair of holes  31  is typically diametrically opposed such that each hole of the pair is directly on the opposite side of axis X from the other and equidistant from axis X. Each of holes  31  is typically substantially identical. Each hole  31  is disposed circumferentially intermediate an adjacent pair of holes  26  and corresponding adjacent pair of bolts  6 . Given the use of five holes  26  and five bolts  6 , as well as the diametrically opposed configuration of holes  31 , each hole  31  may be closer to one of the holes  26  and bolts  6  than the other of the holes  26  and bolts  6  of the adjacent pair between which the given hole  31  is circumferentially disposed. 
         [0019]    Hub sleeve  22  has inboard and outboard ends  28  and  30  which serve as the inboard and outboard ends of hub  2 . Sleeve  22  has a sleeve inboard section  32  and a sleeve outboard section  34  such that inboard section  32  extends in the inboard direction to inboard end  28 , and outboard section  34  extends in the outboard direction from flange  24  to outboard end  30 . Sleeve  22  defines a through passage  36  which serves as a spindle receiving passage for receiving a spindle of a wheeled vehicle for rotatably mounting assembly  1  and a rim and tire thereon. Passage  36  extends from inboard end  28  to outer end  30  and is defined by an inner perimeter or surface  38  which is circular as viewed in the axial direction. Inner perimeter or surface  38  includes an outboard bearing seat  40  which is typically cylindrical and extends inwardly from inboard end  28  to a shoulder  46  which extends radially inwardly from the inboard end of seat  40 . Perimeter  38  also includes an inboard bearing seat  42  and seal seat  44 . Seal seat  44  is typically cylindrical and extends in the outboard direction from adjacent inboard end  28  to a shoulder  48  at the outboard end of seat  44 . Inboard bearing seat  42  is typically cylindrical and extends in the outboard direction from adjacent shoulder  48  to a shoulder  50  which extends radially inwardly from the outboard end of seat  42 . Shoulder  48  extends radially inwardly from seal seat  44  to inboard bearing seat  42 . Seat  40  is configured to receive therein an outboard bearing which id mounted on and circumscribes a spindle when assembly  1  is mounted on said spindle. Similarly, seat  42  is configured to receive therein an inboard bearing which also circumscribes the spindle when mounted thereon. Seat  44  is configured to receive a seal bearing which also circumscribes the spindle when mounted thereon. 
         [0020]    Brake rotor  4  includes a hat or hat section  52  and a friction section or disc section  54  which is rigidly secured to and extends radially outwardly from hat  52 . Hat  52  includes an annular wheel bolt flange  56  which is typically a circular annular plate which may extend perpendicular to axis X. Hat  52  also includes a circular annular sidewall  58  which extends in the inboard direction from flange  56 . Sidewall  58  may extend parallel to axis X. Flange  56  has a circular inner perimeter  60  which is adjacent and spaced radially outwardly from the outer perimeter of sleeve outboard section  34  adjacent the inboard end of section  34  and outboard surface  27  of flange  56 . Flange  56  has an outer perimeter  62 , and inboard and outboard surfaces  64  and  66  which extend radially outwardly from adjacent inner perimeter  60  to adjacent outer perimeter  62  and which may be perpendicular to axis X. Sidewall  58  has inner and outer perimeters  68  and  70  which are circular and concentric about axis X and which may be cylindrical. Sidewall  58  has inboard and outboard ends  72  and  74  such that inner and outer perimeters  66  and  68  extend from adjacent end  72  to adjacent end  74 . Outboard end  74  is rigidly secured to flange  56  adjacent outer perimeter  62  thereof and extends in the inboard direction therefrom to inboard end  72 . 
         [0021]    Bolt flange  56  defines therein a plurality of bolt holes  65  which are typically threaded and threadingly engage the externally threaded portions of bolts  6  to secure hub  2  to rotor  4 . In the sample embodiment, there are five bolt holes  65  which are respectively aligned with holes  26  in flange  24  such that bolts  6  extend through a given pair of aligned holes  26  and  65  such that a threaded section of each bolt or stud  6  extends in the outboard direction beyond outboard surface  66  to provide sufficient space for mounting the rim of a wheel thereon with lug nuts threaded onto bolts  6 . Flange  24  may also define a plurality of anode receiving holes  67  which may be threaded holes and which may be aligned with holes  31  respectively. In this case, holes  67  are likewise diametrically opposed and have a similar position with respect to holes  26  and bolts  6  as do holes  31 . Where such holes are used, holes  67  may extend in the outward direction from inboard surface  64  and may extend to outboard surface  66 . 
         [0022]    Disc section  54  has a circular annular configuration with inner and outer perimeters  76  and  78  which are circular and concentric about axis X. Section  54  also has inboard and outboard surfaces  80  and  82  which extend radially outwardly from adjacent inner perimeter  76  to adjacent outer perimeter  78  and which are typically perpendicular to axis X. Surfaces  80  and  82  serve as friction surfaces or braking surfaces which are engaged by brake pads of a brake caliper when assembly  1  is mounted with a brake system including such a caliper. As is well known in the art, disc section  54  may be formed of a single plate which defines the friction surfaces analogous to surfaces  80  and  82 . In the sample embodiment, the brake rotor is a vented rotor which includes a circular annular inboard plate or disc  84 , a circular annular outboard plate or disc  86  and a plurality of vanes  88  which are rigidly secured to and extend between plates  84  and  86  such that the plates are axially spaced from one another and such that vanes  88  are circumferentially spaced from one another. There are typically multiple vanes which are spaced circumferentially from one another all the way around discs  84  and  86  extending between the inner and outer perimeters  76  and  78 . For example, there may be at least  20 ,  25 ,  30 ,  35 , or  40  or more vanes. When there are two plates or discs  84  and  86 , surfaces  80  and  82  respectively serve as the inboard surface of plate  84  and the outboard surface of plate  86 . Plates  84  and  86  respectively include an inboard surface  90  and an outboard surface  92  which face one another and define therebetween an annular circular space  94  in which vanes  88  are disposed. Each adjacent pair of vanes  88  defines therebetween a vent passage  96  such that there are multiple vent passages  96  along the circumference of the discs between inner and outer perimeters  76  and  78 . As known in the art, vent passages  96  are provided to facilitate the flow of air therethrough to facilitate dissipation of the heat created in rotor  4  during the braking process. 
         [0023]    One or both of the inboard and outboard plates  84  and  86  may define a plurality of anode receiving holes such as holes  95  which are shown formed in inboard plate  84 . Holes  95  may be threaded holes and in the sample embodiment extend from outboard surface  80  to outboard surface  92  of plate  84 . In the sample embodiment, four holes  95  are shown in  FIG. 1  such that one pair of the holes is diametrically opposed on opposite sides of axis X and another pair is likewise diametrically opposed on opposite sides of axis X and such that each pair of diametrically opposed holes is formed at a 90 degree angle with respect to the other pair of diametrically opposed holes as viewed along axis X. Each pair of diametrically opposed holes is preferably equidistant from axis X and typically all of holes  95  are equidistant from axis X. 
         [0024]    Sleeve or anode  10  has an inboard end  98 , an outboard end  100  and inner and outer perimeters  99  and  101  extending from adjacent end  98  to adjacent end  100 . Sleeve  10  includes a wider segment  102  and a narrower segment  104  separated by a shoulder  106 . More particularly, the wider section  102  has a greater outer diameter of outer perimeter  101  than does narrower segment  104 . Shoulder  106  extends radially inwardly from the inboard end of segment  102  to the outboard end of segment  104  and serves as a stop which may abut the outboard end  30  of hub  2  to limit the depth of insertion of the insertion portion or segment  104  into passage  36  when sleeve  10  is mounted on hub  2 . Wider segment  102  includes an internally threaded section  108  of inner perimeter  99  adjacent outboard end  100 . When sleeve  10  is mounted on hub  2 , the insert segment  104  is inserted into or received within passage  36  adjacent outboard end  30  and adjacent or within bearing seat  40  such that shoulder  106  may engage outboard end  30  of hub  2 . Wider segment  102  is external to passage  36  and extends in the outboard direction from the outboard end of passage  36  and outboard end  30 . 
         [0025]    Dust cap  12  includes a generally cylindrical sidewall  110  which is essentially concentric about axis X, and a flat circular cap wall  112  which is rigidly secured to and extends radially inward from the outboard end of sidewall  110 . Sidewall  110  includes an externally threaded segment  114  which threadedly engages threaded segment  108  of sleeve  10  to removably secure dust cap  12  to sleeve  10 . Sidewall  110  may include a shoulder  116  which faces in the inboard direction outboard and threaded segment  114  such that shoulder  116  may engage outboard end  100  of sleeve  10  when dust cap  12  is secured to sleeve  10  by the threaded engagement between segments  114  and  108 . Dust cap  12  may thus easily be secured to sleeve  10  by threading dust cap  12  onto sleeve  10  and removed therefrom by unthreading the dust cap. An annular seal  118  such as a gasket or a compressible O-ring may be disposed outboard of threaded segment  114  and inboard of shoulder  116  to provide a seal between the outer perimeter of sidewall  110  and the inner perimeter  99  of sleeve  10 . 
         [0026]    Each of anodes  14  has an inboard end  120  and an outboard end  122 , a first segment  124  which may be a threaded segment, a second segment  126  which may be an unthreaded segment and a tool engaging hole  128  which may for example be a hexagonal hole for receiving therein a hex wrench although various other shapes may be used. In the sample embodiment, segment  124  extends in the outboard direction from adjacent inboard end  120  about halfway to end  122 , and segment  126  extends from the outboard end of segment  124  to outboard end  122 . First segment  124  is disposed within one of holes  95  while second segment  126  is disposed in or extends within one of passages  96 . Inboard end  120  may be flush with or recessed from surface  80 , while outboard end  122  may be within the given passage  96  and may abut inboard surface  90 . In the sample embodiment, segment  124  may be externally threaded and thereby threadedly engage the internally threaded hole  95  to form a threaded connection which secures anode  14  to plate  84 . In the sample embodiment, anode  14  is in direct contact with plate  84  and plate  86 , thereby providing direct electrical communication or contact between the given anode  14  and both plates  84  and  86 . While the sample embodiment provides a threaded engagement between the given anode  14  and plate  84  within hole  95 , anodes  14  may also be press fit into holes  95  and thus secured by a press fit connection without the use of a threaded segment or threaded engagement between the anode and plate. Holes may also be formed in plate  86  which are aligned with holes  95  such that each anode  14  may extend into such holes in plate  86  with or without a threaded connection therein. Inasmuch as anodes  14  are disposed within holes  95 , anodes  14  are thus positioned relative to one another in the same manner as holes  95  are positioned relative to one another as described in greater detail further above. Thus, anodes  14 A and  14 C are a pair of diametrically opposed anodes which are equidistant from axis X. Likewise, anodes  14 B and  14 D are a pair of diametrically opposed anodes which are equidistant from axis X. Each pair of diametrically opposed anodes  14 A and  14 C is formed at a 90 degree angle with respect to the other pair of diametrically opposed anodes  14 B and  14 D as viewed along axis X. Typically, all of anodes  14  are equidistant from axis X. In the sample embodiment, all of anodes  14  have the same dimensions and weight and are essentially identical whereby their positioning ensures that assembly  1  is weight balanced during rotation about axis X. 
         [0027]    Each anode  15  may essentially be a block and have a box shape or parallelepiped configuration. In the sample embodiment, anode  15  has flat inboard and outboard surfaces  130  and  132  which are parallel, radial inner and outer ends or surfaces  134  and  136  which are parallel to one another and perpendicular to surfaces  130  and  132 , and circumferential ends or surfaces  138  and  140  which are parallel to one another and perpendicular to surfaces  130  and  32  and ends or surfaces  134  and  136 . Anode  15  may define a plurality of slots  142 . In the sample embodiment, four slots  142  are formed in anode  15 , with two of slots  142  extending inwardly from circumferential end  138  toward end  140 , and two of slots  142  extending inwardly from end  140  toward end  138 . Thus, two of the slots are open ended at end or surface  138  and the other two slots  142  are open ended at end or surface  140 . Each of the slots  142  also extends from inboard surface  130  to outboard surface  132  and thus is open ended at both these surfaces as well. Each slot  142  extends inwardly into anode  15  to a closed end. 
         [0028]    A plurality of connectors  144  are secured to anode  15  and extend outwardly therefrom such that portions of connectors  144  extend outwardly in the inboard direction beyond inward surface  130  and other portions of connectors  144  extend in the outboard direction beyond outboard surface  132 . In the sample embodiment, connectors  144  are springs formed of spring steel which have opposed ends  146 . The body of each spring  144  is received in a given slot  142  such that each spring  144  is secured to anode  15 . The inboard end  146  of a given spring  144  extends outwardly out of a given slot  142  beyond inboard surface  130  in the inboard direction, while the outboard end  146  of a given spring extends out of a given slot  142  beyond outboard surface  132  in the outboard direction. Each spring  144  is curved such that ends  146  extend or are angled toward the radial outer end  136  of anode  15 . 
         [0029]    Anode  15  is secured to brake rotor  4  by inserting the given anode  15  with connectors  144  secured thereto into one of vent passages  96  in a radial inward direction from the outer perimeter  78  toward the inner perimeter  76  and toward axis X. During insertion of anode  15  into the given passage  96 , ends  46  slidably engage surfaces  90  and  92  of plates  86  and  84  respectively. Once anode  15  is mounted within passage  96 , the inboard ends  146  of springs  144  engage outboard surface  92  and the outboard ends  146  engage inboard surface  90 , thus providing a press fit or interference fit between the ends of the springs and surfaces  90  and  92  to secure anode  15  to discs  84  and  86 . In this secured position, ends  146  extend or are angled radially outwardly away from axis X and inner perimeter  76  and toward outer perimeter  78 . Inboard surface  130  is adjacent and faces outboard surface  92 , while outboard surface  132  is adjacent and faces inboard surface  90 . Surfaces  130 ,  132 ,  90 , and  92  may be parallel. Radial inner end or surface  134  faces radially inwardly toward axis X, while radial outer end or surface  136  faces radially outwardly away from axis X. Anode  15  is in electrical communication with plates  84  and  86  via connectors  144 . More particularly, each anode  15  is in direct electrical communication or contact with connectors  144 , which are in turn in direct electrical communication or contact with plates  84  and  86  via contact between ends  146  and the respective surfaces  90  and  92 . 
         [0030]    As shown in  FIG. 1 , anodes  15 A-D are arranged in a pattern similar to that of anodes  14 A-D. Thus, anodes  15 A and  15 C are a pair of diametrically opposed anodes which are equidistant from axis X. Likewise, anodes  15 B and  15 D are a pair of diametrically opposed anodes which are equidistant from axis X. Each pair of diametrically opposed anodes  15 A and  15 C is formed at a 90 degree angle with respect to the other pair of diametrically opposed anodes  15 B and  15 D as viewed along axis X. Typically, all of anodes  15  are equidistant from axis X. In the sample embodiment, all of anodes  15  have the same dimensions and weight and are essentially identical whereby their positioning ensures that assembly  1  is weight balanced during rotation about axis X. 
         [0031]    Anodes  16  each have an inboard end  148  and an outboard end  150 . Each anode  16  includes a first segment  152  which may be a threaded segment, and may also include a second segment  154  (shown in dashed lines in  FIG. 3 ). Segment  152  may define a tool engaging hole  128  such as a hexagonal hole or other shape as discussed previously. Each anode  16  is received within a respective hole  31  and may also extend into a hole  67  aligned with hole  31 . In the sample embodiment, anode  16  in solid lines is shown only within hole  31  with outboard surface  150  in contact with inboard surface  64  of flange  56 . If segment  152  is threaded, there may be a threaded engagement or connection between the externally threaded segment  152  and internally threaded hole  31  to secure anode  16  to flange  24  of hub  2 . In the sample embodiment, anode  16  is thus in direct electrical communication or contact with flange  24  and flange  56 . 
         [0032]    As with the other anodes, anodes  16 A and  16 B are typically diametrically opposed and equidistant from axis X, and are essentially identical and have the same weight so that assembly  1  is weight balanced during rotation about axis X. It is noted that anodes such as anodes  14 ,  15  and  16  may be positioned other than in the diametrically opposed configuration while still maintaining the weight balance of assembly  1 . For instance, three anodes which are essentially identical may be circumferentially spaced about axis X (120 degrees apart) such that they are equidistant from axis X and equidistant from one another. Other weight balanced configurations will be understood by one skilled in the art. 
         [0033]    In the foregoing description, certain terms have been used for brevity, clearness, and understanding. No unnecessary limitations are to be implied therefrom beyond the requirement of the prior art because such terms are used for descriptive purposes and are intended to be broadly construed. 
         [0034]    Moreover, the description and illustration set out herein are an example and the invention is not limited to the exact details shown or described.