Patent Publication Number: US-2023160435-A1

Title: Rotatable shield for wheel bearing assemblies

Description:
BACKGROUND OF THE INVENTION 
     The present invention relates to bearings, and more particularly to wheel bearing assemblies. 
     Wheel bearing assemblies, particularly for mounting wheels to vehicles such as trucks, typically include an outer hub connectable to the wheel and an inner axle mounted to a vehicle frame. The bearings are often double-row tapered rollers disposed between the outer hub and the inner axle and enable the hub, and thereby the wheel, to rotate about a central axis extending through the fixed axle. As such bearings are generally exposed to contaminants such as dust, mud, oil, metal shavings, etc., which may damage the bearings if contacting the rolling elements or the bearing raceway surfaces, one or more seals are provided adjacent to the raceways to exclude such contaminants. When operating in particularly extreme environments, these seals may become damaged through repeated contact or exposure to such contaminants, necessitating replacement of the seals. 
     SUMMARY OF THE INVENTION 
     In one aspect, the present invention is a wheel bearing assembly comprising a fixed inner axle having a central axis and at least one bearing inner race. A rotatable outer hub has a central bore, the inner axle being disposed within the hub central bore such that an annular interior space is defined between the inner axle and the outer hub, and at least one bearing outer race disposed radially about the at least one bearing inner race. A plurality of rolling elements are disposed between the at least one inner race and the at least one outer race so as to rotatably couple the outer hub with the inner axle. An annular seal is disposed between the inner axle and the outer hub and is located adjacent to the inner race and to the outer race. Further, a shield is spaced axially from the seal such that the seal is disposed between the plurality of rolling elements and the shield. The shield includes a rigid annular body having an outer radial end coupled with the outer hub and an inner radial end, the inner radial end defining a central opening for receiving the axle and being located adjacent to the inner axle or a component disposed upon the axle. As such, the annular body is configured to substantially obstruct a section of the annular interior space to prevent substances from contacting the seal. 
     In another aspect, the present invention is again a wheel bearing assembly as described in the preceding paragraph and further comprising at least one coupler connected with the annular body outer end and configured to connect the annular body with the outer hub such that at least one drain passage is defined between the rigid annular body and the outer hub. 
    
    
     
       BRIEF DESCRIPTION OF THE SEVERAL VIEWS OF THE DRAWINGS 
       The foregoing summary, as well as the detailed description of the preferred embodiments of the present invention, will be better understood when read in conjunction with the appended drawings. For the purpose of illustrating the invention, there is shown in the drawings, which are diagrammatic, embodiments that are presently preferred. It should be understood, however, that the present invention is not limited to the precise arrangements and instrumentalities shown. In the drawings: 
         FIG.  1    is an axial cross-sectional view of an upper portion of a wheel bearing assembly having two shields in accordance with a first construction of the present invention, shown with an inner axle disposed about a rotatable central shaft; 
         FIG.  2    is a more enlarged, axial cross-sectional view of an outboard portion of  FIG.  1   ; 
         FIG.  3    is a view through line  3 - 3  of  FIG.  2   ; 
         FIG.  4    is a side plan view of the first construction shield shown with eight couplers; 
         FIG.  5    is another side plan view of the first construction shield shown with four couplers; 
         FIG.  6    is an axial cross-sectional view of the first construction shield disposed between a bearing inner ring and an outer hub, shown with couplers frictionally engaged with an inner surface of the hub; 
         FIG.  7    is another axial cross-sectional view of the first construction shield, shown with an inner radial end of a shield annular body disposed within a groove of the bearing inner ring; 
         FIG.  8    is an axial cross-sectional view of a second construction shield disposed between the bearing inner ring and the outer hub and having an annular body with an outer axial portion, the shield body having an inner radial end spaced outwardly from the bearing inner ring; 
         FIG.  9    is another axial cross-sectional view of the second construction shield, the shield body having an inner radial end disposed within a groove of the bearing inner ring; 
         FIG.  10    is another axial cross-sectional view of the second construction shield, shown with couplers located centrally on a body outer axial portion and with the body inner radial end being disposed within a groove of the bearing inner ring; 
         FIG.  11    is an axial cross-sectional view of a third construction shield disposed between the bearing inner ring and the outer hub and having an annular body with an outer axial section and an inner axial section; 
         FIG.  12    is an axial cross-sectional view of a fourth construction shield disposed between the bearing inner ring and the outer hub and having an annular body with a radial portion, including an inner disk section and an outer frustoconical section, and a cylindrical outer axial portion; 
         FIG.  13    is another axial cross-section view of the fourth construction shield, shown with a frustoconical outer axial portion spaced from a cylindrical inner surface of the hub; 
         FIG.  14    is another axial cross-section view of the fourth construction shield, shown with a frustoconical outer axial portion spaced inwardly from a tapered inner surface of the hub; 
         FIG.  15    is another axial cross-sectional view of the fourth construction shield, shown with an inner radial end disposed within a groove of the bearing inner ring; 
         FIG.  16    is an axial cross-sectional view of a fifth construction shield disposed between the bearing inner ring and the outer hub and having an annular body with a radial portion, including an inner disk section and an outer frustoconical section, and having both a cylindrical outer axial portion and a cylindrical inner axial portion; and 
         FIG.  17    is another axial cross-sectional view of the fifth construction shield, further including an inner radial portion extending inwardly from the inner axial portion and into a groove on the bearing inner ring. 
     
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
     Certain terminology is used in the following description for convenience only and is not limiting. The words “inner”, “inwardly” and “outer”, “outwardly” refer to directions toward and away from, respectively, a designated centerline or a geometric center of an element being described, the particular meaning being readily apparent from the context of the description. Further, as used herein, the words “connected” and “coupled” are each intended to include direct connections between two members without any other members interposed therebetween and indirect connections between members in which one or more other members are interposed therebetween. Further the term “axle” is intended to include an inner axle  16  as described below and any component mounted on the axle  16  and the term “hub” is intended to include an outer hub  18  as described below and any component mounted within the hub  18 . The terminology includes the words specifically mentioned above, derivatives thereof, and words of similar import. 
     Referring now to the drawings in detail, wherein like numbers are used to indicate like elements throughout, there is shown in  FIGS.  1 - 17    a secondary seal or “shield”  10  for a wheel bearing assembly  12 , the shield  10  functioning to prevent substances (e.g., contaminants) from contacting or passing to a primary seal  14 . The wheel hub assembly  12  is preferably optimized for use in an electrically powered or “electric” truck and basically comprises a fixed inner axle  16 , a rotatable outer hub  18  disposed about the inner axle  16 , a plurality of rolling elements  26  rotatably coupling the axle  16  and the hub  18 , at least one primary seal  14  and at least one shield  10 . More specifically, the inner axle  16  is fixedly connected with a vehicle frame (not shown) and has a central axis A C , an outer circumferential surface  16   a  and at least one and preferably two bearing inner races  22 . The inner races  22  are each preferably provided by a separate bearing inner ring  23  disposed about the axle  16  and retained thereon by a nut  21 , but may alternatively be formed directly on the axle outer surface  16   a . The outer hub  18  is connected with a drive shaft  1 , has a flange portion  18   d  connected with a wheel (not shown) and is connected with a steering mechanism and/or a suspension assembly (neither shown). The hub  18  has a central bore  19 , the axle  16  being disposed within the hub central bore  19  such that an annular interior space S 1  is defined between the inner axle  16  and the outer hub  18 , and at least one and preferably two outer races  24  each disposed radially about a separate one of the inner races  22 . Each outer race  24  is preferably provided by a separate bearing outer ring  25  disposed within the hub bore  19 , but may alternatively be directly formed on the hub inner surface  18   c  defining the bore  19 . 
     Further, a plurality of rolling elements  26  are disposed between the at least one inner race  22  and the at least one outer race  26  so as to rotatably couple the outer hub  18  with the inner axle  16 . Preferably, two sets or “rows”  27 A,  27 B of the rolling elements  26  are each disposed between a separate pair of aligned inner and outer races  22 ,  24 , such that the wheel bearing assembly  12  is a “double row” bearing, as depicted in  FIG.  1   . The rolling elements  26  are preferably tapered rollers as shown in  FIG.  1   , but may alternatively be any other known type of rolling element, such as balls, cylindrical rollers, spherical rollers, needles, etc. 
     Furthermore, the wheel hub assembly  12  preferably includes two of the primary seals  14 , each seal  14  being disposed between the inner axle  16  and the outer hub  18  and located adjacent to a separate one of the inner races  22  and the associated outer race  24 . Specifically, each primary seal  14  is located axially “outward” of each rolling element row  27 A,  27 B and a proximal axial end  18   a ,  18   b  of the outer hub  18  and functions to both retain lubricant about, and prevent contaminants from contacting, the rolling elements  26  and the inner and outer races  22 ,  24 . Each seal  14  may be coupled with the inner axle  16  and configured to seal against the hub bore  19  or a component disposed within the bore  19 , such as a bearing outer ring  25 , or each seal  14  may be coupled with the outer hub  18  and configured to seal against the axle  16  or a component disposed about the axle  16 , such as one of the bearing inner rings  23 , a nut  21 , etc. 
     Also, each primary seal  14  is depicted in the present application as a generic “block” element in the drawing figures without any specific details as each seal  14  may be formed in any appropriate manner. For example, each seal  14  may be formed as a radial lip seal including one or more radially-extending sealing lips, as an axial “face” seal with one or more axially-extending sealing lips, a combination seal with both radial and axial sealing lips, a seal with a single case or with both inner and outer cases forming a “cassette”, etc. The present invention encompasses all known types of seals and is not limited to any particular structure of the primary seal(s)  14 . 
     Still referring to  FIGS.  1 - 18   , the wheel hub assembly  12  preferably includes two of the shields  10  each spaced axially from a separate one of the primary seals  14 , such that each seal  14  is disposed between one row  27 A or  27 B of rolling elements  26  and the adjacent shield  10 , as best shown in  FIG.  1   . However, the wheel hub assembly  12  may include only one shield  10  located between one seal  14  and the axial end  18   a  or  18   b  of the hub  18  which is most likely to experience an ingress of contaminants or any other substances. In any case, each shield  10  basically includes a rigid annular body  30  with a central opening  31  for receiving a portion of the inner axle  16  and at least one and preferably a plurality of couplers  32 . 
     Specifically, the annular body  30  has an outer radial end  30   a  coupled with the outer hub  18 , such that the shield  10  rotates with the hub  18  about the central axis A C , and an inner radial end  30   b . The inner radial end  30   b  defining the central opening  31  ( FIGS.  4  and  5   ) for receiving a portion of the axle  16  and being located radially adjacent or proximal to the inner axle  16  or a component (e.g., a bearing inner ring  23 ) disposed about the axle  16 . The inner radial end  30   b  may be sized so as to be spaced radially outwardly from the inner axle  16 , or from a bearing inner ring  23 , a nut  21  or a washer  28  ( FIG.  17   ) disposed about the axle  16 , so as to define an annular labyrinth gap  36  between the shield  10  and the axle  16 . Alternatively, the axle  16 , the inner ring  23 , the nut  21  or the washer  28  may be formed with an annular groove  37  and the inner radial end  30   b  of the rigid annular body  30  may be sized so as to be disposed within the groove  37  and define a generally U-shaped labyrinth gap  38 . In either case, each rigid annular body  30  is configured to substantially obstruct a section of the annular interior space S 1  to prevent substances from contacting the proximal seal  14 , as discussed in further detail below. 
     Further, the one or more couplers  32  are each connected with the outer radial end  30   a  of the rigid annular body  30 , and preferably a plurality of the couplers  32  are spaced circumferentially about the body outer radial end  30   a . The coupler(s)  32  is/are configured to connect the rigid annular body  30  with the outer hub  18  such that at least one and preferably a plurality of drain passages  34  is/are defined between the rigid annular body  30  and the outer hub  18 , which enables the expulsion of substances (i.e., contaminants) located between the shield  10  and the seal  14 , as described below. In certain constructions as shown in  FIGS.  1 - 3  and  7 - 17   , the outer hub  18  or a component disposed within the hub  18  (e.g., one of the bearing outer rings  25 ) includes an annular groove  33  and at least a portion of each coupler  32  is disposed within the annular groove  33 , to thereby couple the shield  10  with the outer hub  18 . In other constructions as depicted in  FIG.  6   , the one or more couplers  32  are each configured to frictionally engage with the inner circumferential surface  18   c  of the outer hub  18 , or with the inner circumferential surface  25   a  ( FIG.  2   ) of one of the bearing outer rings  25 , to couple the shield  10  with the outer hub  18 . 
     In either case, the coupler(s)  32  retain the shield  10  to the outer hub  18  such that the outer radial end  30   b  of the rigid annular body  30  is spaced radially inwardly from the inner surface  18   c  of the hub  18 , or the inner surface  25   a  of one bearing outer ring  25  (or other component disposed within the hub bore  19 ), such that an annular space  35  is defined between the shield  10  and the outer hub  18 , as best shown in  FIG.  3   . The drain passages  34  are provided by arcuate sections of the annular space  35  between each circumferentially adjacent pair of couplers  32 , as indicated in  FIG.  3   . Further, each coupler  32  is preferably formed as an arcuate projection with generally rectangular axial cross-sections, but may be formed in any other appropriate manner, such as for example, a bendable clip, etc. 
     Preferably, the rigid annular body  30  of the shield seal  10  is integrally formed, i.e., of one-piece construction, but may alternatively be formed of a plurality of separate components formed in one of the structures as described in detail below and connected by any appropriate means. The coupler(s)  32  are preferably integrally formed with the rigid annular body  30 , but may instead be formed of one or more separate components attached to the annular body  30 , such as attached clips, etc. Further, the annular body  30  is preferably formed of a molded polymeric material, but may be formed of a metallic material, such as for example, a stamped or sintered steel, or any other appropriate material. 
     With the structure described above, each shield  10  serves to both increase the sealing efficiency of the primary seal  14  and to extend or prolong the functional life of the seal  14  by preventing or at least reducing the amount or volume of external contaminants, such as dust, metal particles, oil, water, etc., or any other substances which may contact the seal  14 . That is, by providing a barrier which substantially blocks or obstructs the annular space S 1  between the outer hub  18  and the inner axle  16 , the amount of liquid and solid contaminants passing through the annular space S 1  and contacting each seal  14  is substantially reduced, some of which, particularly metal particles, can readily damage any elastomeric portions of the seal  14 . By being spaced from the inner axle  16  and only coupled with the outer hub  18 , the shield  10  provides substantial sealing without increasing friction within the wheel hub assembly  12 . Further, by providing the drain passages  34 , at least some of any contaminants which pass through the narrow gap  36  or  38  between the shield  10  and the axle  16  are directed out of the region between each shield  10  and the adjacent seal  14 , as discussed below. Having described the basic structure and functions above, these and other details of the present shield  10  are described in additional detail below. 
     Referring to  FIGS.  3 - 8   , in a first, most basic construction, the rigid annular body  30  is formed as a substantially flat circular disk  40  having inner and outer circular edges  40   a ,  40   b , respectively, and opposing radial surfaces  41 A,  41 B. The inner circular edge  40   a  defines the body central opening  31  and the preferred plurality of couplers  32  are spaced circumferentially about, and each extend radially outwardly from, the outer circular edge  40   b  of the circular disk  40 . As discussed above, the inner circular edge  40   a  of the disk  40  may be spaced radially outwardly from the inner axle  16 , the inner ring  23 , the nut  21  or the washer  28  to define the annular labyrinth gap  36 , as depicted in  FIGS.  2 ,  3  and  6   , or disposed within the groove  37  formed in the particular component and defining the U-shaped labyrinth gap  38 , as shown in  FIG.  7   . Further, the disk radial surface  41 A facing the seal  14  is configured to direct substances, i.e., contaminants, contacting the disk  40  generally radially outwardly and into the drain passages  34  by centrifugal force during rotation of the outer hub  18 . 
     Referring to  FIGS.  8 - 10   , in a second construction, the rigid annular body  30  is formed to include a radial portion  50  providing the central opening  31  and an outer axial portion  52  providing the body outer radial end  30   b  and extending axially from the radial portion  50  in a direction generally away from the seal  14 . Specifically, the radial portion  50  includes inner and outer circular edges  50   a ,  50   b , the inner edge  50   b  defining the central opening  31 , and opposing radial surfaces  51 A,  51 B. The inner radial edge  50   a  may be spaced outwardly from the axle  16  or a component  21 ,  23  or  28  disposed thereon or within an annular groove  37  formed therein, and the radial surface  51 A is configured to direct substances radially outwardly and into the drain passages  34  during hub rotation. 
     Further, the body axial portion  52  is generally cylindrical and has a first axial end  52   a  integrally formed with the outer circular edge  50   b  of the radial portion  50 , a second, free axial end  52   b , and inner and outer circumferential surfaces  53 A,  53 B. The outer circumferential surface  53 B of the axial portion  52  is spaced radially inwardly of the hub inner surface  18   c  or the outer ring inner surface  25   a  so as to define an outer annular labyrinth gap  54 , which functions both as a labyrinth seal to prevent ingress of contaminants and leads into the drain passage(s)  34 . Furthermore, the preferred plurality of couplers  32  extend radially outwardly from the outer axial portion  52  and may be positioned at least generally adjacent to the second, free axial end  52   b , as shown in  FIGS.  8  and  9   , generally adjacent to the first axial end  52   a  (not shown) or at an axial position between the two ends  52   a ,  52   b , as depicted in  FIG.  10   . 
     Referring particularly to  FIG.  11   , a third construction of the shield  10  has a rigid annular body  30  with a radial portion  60  providing the central opening  31 , an outer axial portion  62  providing the body outer radial end  30   b  and an inner axial portion  64  providing the body inner radial end  30   a , each axial portion  62 ,  64  extending axially from the radial portion  60  in a direction generally away from the seal  14 . Specifically, the radial portion  60  includes inner and outer circular edges  60   a ,  60   b  and opposing radial surface sections  61 A,  61 B. The outer axial portion  62  is generally cylindrical and has a first axial end  62   a  integrally formed with the outer circular edge  60   b  of the radial portion  60 , a second, free axial end  62   b , and inner and outer circumferential surfaces  63 A,  63 B. The outer circumferential surface  63 B of the outer axial portion  62  is spaced radially inwardly of the hub inner surface  18   c  or outer ring inner surface  25   a  so as to define an outer annular labyrinth gap  66 , and the preferred plurality of couplers  32  extend radially outwardly from the outer axial portion  62 . Further, the inner axial portion  64  is also generally cylindrical and has a first axial end  64   a  integrally formed with the inner circular edge  60   a  of the radial portion  60 , a second, free axial end  64   b , and inner and outer circumferential surfaces  65 A,  65 B. The inner circumferential surface  65 B of the inner axial portion  64  is spaced radially outwardly of the inner axle  16  or a component  21 ,  23  or  28  disposed thereon so as to form the annular gap  36  with an extended length. 
     Referring now the  FIGS.  12 - 15   , in a fourth construction of the shield  10 , the rigid annular body  30  includes a radial portion  70  and an outer axial section  72 , the radial portion  70  having an inner disk section  74  and an outer frustoconical section  76 . The disk section  74  of the radial portion  70  has an inner circular edge  74   a  providing the body inner radial end  30   b , which defines the body central opening  31 , and opposing radial surfaces  75 A,  75 B. The disk section inner edge  74   a  is either spaced radially outwardly from the inner axle  16  and forms the annular labyrinth gap  36 , as shown in  FIGS.  12 - 14   , or is disposed with an annular groove  37  and forms the U-shaped labyrinth gap  38  as depicted in  FIG.  15   . Further, the frustoconical section  76  of the radial portion  70  has an outer radial edge  76   a  and opposing inclined radial surfaces  77 A,  77 B, and is configured to direct substances or contaminants contacting the radial surface  77 A radially and axially toward the drain passages  34  during rotation of the outer hub  18 . 
     Further, the body axial portion  72  extends axially from the radial portion  70  in a direction generally away from the seal  14  and has a first axial end  72   a  integrally formed with the outer radial edge  76   a  of the frustoconical section  76 , an opposing second axial end  72   b  and opposing circumferential surfaces  73 A,  73 B. The outer circumferential surface  73 B of the outer axial portion  72  is spaced radially inwardly of the hub inner surface  18   c  or the outer ring inner surface  25   a  so as to define an outer annular labyrinth gap  78 , and the preferred plurality of couplers  32  extend radially outwardly from the axial portion  72 . The outer axial portion  72  may be formed generally cylindrical, as shown in  FIG.  12   , or formed generally frustoconical so as to direct substances both radially and axially through the drain passages  34 , as depicted in  FIGS.  13 - 15   . 
     Referring to  FIGS.  16  and  17   , a fifth construction of the rigid annular body  30  includes a radial portion  80  with an inner disk section  82  and an outer frustoconical section  84 , an outer axial portion  86  and an inner axial portion  88 , each axial portion  82 ,  84  extending axially from the radial portion  80  in a direction generally away from the seal  14 . The disk section  82  has an inner end  82   a  and opposing radial surfaces  83 A,  83 B and the frustoconical section  84  has an outer radial end  84   a  and opposing inclined radial surfaces  85 A,  85 B and is configured to direct substances or contaminants contacting the radial surface  85 A radially and axially toward the drain passages  34  during rotation of the outer hub  18 . The outer axial portion  86  is generally cylindrical and has a first axial end  86   a  integrally formed with the outer end  84   a  of the radial portion frustoconical section  84 , a second, free axial end  86   b , and inner and outer circumferential surfaces  87 A,  87 B. The outer circumferential surface  87 B of the axial portion  86  is spaced radially inwardly of the hub inner surface  18   c  or outer ring inner surface  25   a  so as to define an outer annular labyrinth gap  81 . 
     Further, the inner axial section  88  is also generally cylindrical and has a first axial end  88   a  integrally formed with an inner circular edge  82  of the disk section  82 , an opposing second axial end  88   b , and inner and outer circumferential surfaces  89 A,  89 B. The inner circumferential surface  89 A of the inner axial portion  88  is spaced radially outwardly of the inner axle  16  or a component  21 ,  23  or  28  disposed thereon so as to form the annular gap  36  with an extended length. Also, as depicted in  FIG.  17   , the annular body  30  may further include an inner radial portion  90  extending radially inwardly from the second axial end  88   b  of the inner axial portion  88 . The inner radial portion  90  is disposed in an annular groove  37  in the axle  16 , or a component  21 ,  23  or  28  on the axle  16 , to provide the U-shaped labyrinth gap  38  leading into the main annular gap  36 . 
     Although five basic constructions of the rigid annular body  30  of the shield  10 , and variations thereof, are described and depicted herein, the scope of the present invention includes these and any other construction of the annular body  30  having an outer radial end  30   a  coupleable with a rotatable outer hub and an inner radial end  30   b  located radially adjacent to an inner axle so as to obstruct an annular space between the hub and axle. 
     Representative, non-limiting examples of the present invention were described above in detail with reference to the attached drawings. This detailed description is merely intended to teach a person of skill in the art further details for practicing preferred aspects of the present teachings and is not intended to limit the scope of the invention. 
     Moreover, combinations of features and steps disclosed in the above detailed description may not be necessary to practice the invention in the broadest sense, and are instead taught merely to particularly describe representative examples of the invention. Furthermore, various features of the above-described representative examples, as well as the various independent and dependent claims below, may be combined in ways that are not specifically and explicitly enumerated in order to provide additional useful embodiments of the present teachings. 
     All features disclosed in the description and/or the claims are intended to be disclosed separately and independently from each other for the purpose of original written disclosure, as well as for the purpose of restricting the claimed subject matter, independent of the compositions of the features in the embodiments and/or the claims. In addition, all value ranges or indications of groups of entities are intended to disclose every possible intermediate value or intermediate entity for the purpose of original written disclosure, as well as for the purpose of restricting the claimed subject matter. The invention is not restricted to the above-described embodiments, and may be varied within the scope of the following claims.