Patent Publication Number: US-2021190146-A1

Title: Double lipped sealed bearing

Description:
I. BACKGROUND 
     A. Technical Field 
     This invention pertains to the field of bearings. More particularly, the invention pertains to the field of sealed bearings that retain a lubricant while preventing the entry of contaminants. 
     B. Description of Related Art 
     Rolling-element bearings are known in the art for supporting a load during rotation. Such bearings include rolling elements, including spherical balls or cylindrical rollers, that are placed between an outer ring and an inner ring. Typically, one bearing ring or the other is held stationary while the other bearing ring is permitted to rotate. The rolling elements roll between the two bearing rings with little frictional resistance. The rolling elements are typically lubricated with a lubricant such as grease or the like to further lower friction and reduce wear on the rolling elements and bearing rings. 
     One problem with prior art bearings is containment since lubricant tends to escape from the interior of the bearing due to the motion of the moving components. Another problem is contamination since common debris tends to enter the bearing from typical environments, such as the outdoors, roadways, and machinery. Sealed bearings are known in the art and include a seal intended to increase containment and reduce contamination. However, typical sealed bearing designs fail to provide adequate mitigation of these ongoing problems. There remains a need for a sealed bearing that overcomes these known problems. 
     II. SUMMARY 
     Provided in this disclosure is a seal for a bearing. The seal includes a seal body that is interposed between an outer ring and an inner ring of a bearing. The seal body is retained between an outer ring groove formed on the outer ring and an inner ring groove formed on the inner ring. Preferably, there are two seals, to cover and protect each of the two sides of a cylindrically shaped bearing. 
     The seal body includes a metal shield portion for engaging either the outer ring groove or the inner ring groove for providing rigid mounting of the seal. Preferably, the metal shield portion engages the outer ring groove and thereby defines the outer diameter of the seal body. However, in an alternative embodiment, the metal shield portion can also engage the inner ring groove and thereby define the inner diameter of the seal body. 
     The seal body also includes a rubber portion for engaging either the outer ring groove or the inner ring groove for providing tight sealing. The rubber portion is molded onto an internal face of the metal shield portion and extends beyond the metal shield portion into the respective groove. Preferably, the rubber portion engages the inner ring groove and thereby defines the inner diameter of the seal body. However, in an alternative embodiment, the rubber portion can also engage the outer ring groove and thereby define the outer diameter of the seal body. 
     According to an aspect of the invention, the present seal has combined characteristic features of a pressed metal shield along with a synthetic rubber labyrinth seal. 
     According to another aspect of the invention, the present seal provides a bearing with superior protection against external debris damage, improper handling, and/or aggressive installation while obtaining improved sealing around the inner and outer rings of the bearing. 
     According to yet another aspect of the invention, the present seal allows for rigid mounting and superior protection against external debris damage. 
     According to still another aspect of the invention, the present seal provides excellent protection against water intrusion while also containing lubricant, which in turn increases bearing efficiency and produce life. 
     Other benefits and advantages of this invention will become apparent to those skilled in the art to which it pertains upon reading and understanding of the following detailed specification. 
    
    
     
       III. BRIEF DESCRIPTION OF THE DRAWINGS 
       The disclosed sealed bearing may take physical form in certain parts and arrangement of parts, embodiments of which will be described in detail in this specification and illustrated in the accompanying drawings which form a part hereof and wherein: 
         FIG. 1  is a perspective view of a half-section of the bearing in accordance with an exemplary embodiment of the present invention. 
         FIG. 2  is a side-sectional view of the bearing of  FIG. 1 , shown along a line A-A, in accordance with an exemplary embodiment of the present invention. 
         FIG. 3  is a detail view of a portion of the side-sectional view of  FIG. 2 , in accordance with an exemplary embodiment of the present invention. 
     
    
    
     IV. DETAILED DESCRIPTION 
     Referring now to the drawings wherein the showings are for purposes of illustrating embodiments of the article only and not for purposes of limiting the same, and wherein like reference numerals are understood to refer to like components: 
     A sealed bearing  10  in accordance with the present invention is generally shown in the view of  FIG. 1 . It is to be understood and appreciated that the entire sealed bearing has a body generally in the shape of a continuous cylindrical annulus, centered along a cylindrical axis  12  which represents an axis of rotation for the sealed bearing  10 . The view of  FIG. 1  represents a half-section generally symmetrical of the complete sealed bearing  10 . 
       FIG. 2  is a cross-section of the annular sealed bearing  10  taken along the sectional line A-A shown in  FIG. 1 . The sealed bearing  10  includes an outer ring  20  and an inner ring  30 . The outer ring  20  is a generally cylindrical outer ring  20  centered along the cylindrical axis  12 . The outer ring  20  includes an outer ring exterior cylindrical surface  22 , which faces outward from the cylindrical axis  12  of the sealed bearing  10 . The outer ring  20  also includes an outer ring interior cylindrical surface  24 , which faces inwardly toward the cylindrical axis  12 . The outer ring  20  also includes first and second outer ring edge surfaces  26   a ,  26   b  spanning the respective exterior and interior cylindrical surfaces  22 ,  24 . 
     The interior cylindrical surface  24  of the outer ring  20  includes first and second outer ring grooves  28   a ,  28   b . Each of the outer ring grooves  28   a ,  28   b  are inset from the respective first and second outer ring edge surfaces  26   a ,  26   b . That is to say, the first outer ring groove  28   a  is formed in the outer ring interior cylindrical surface  24  at a position that is set in from first edge surface  26   a . Similarly, the second outer ring groove  28   b  is formed in the interior outer ring cylindrical surface  24  at a position that is set in from second edge surface  26   b . These outer ring grooves  28   a ,  28   b  help retain the present seal body, as will be explained in detail hereinbelow. 
     The inner ring  30  of the sealed bearing  10  is a generally cylindrical inner ring  30  also centered along the cylindrical axis  12 . The inner ring  30  is generally coaxial with the outer ring  20 . The inner ring  30  has an outer diameter smaller than the inner diameter of the outer ring  20  so that the inner ring  30  can be retained concentrically within the outer ring  20  with a space in between that defines a volume for retaining rolling elements, as will be explained in detail hereinbelow. The inner ring  30  includes an inner ring exterior cylindrical surface  32 , which faces outward from the cylindrical axis  12  of the sealed bearing  10 . The inner ring  30  also includes an inner ring interior cylindrical surface  34 , which faces inwardly toward the cylindrical axis  12  and generally defines a bore that can receive a stationary axle, rotating shaft, or other such load-bearing structure used with bearings, as is understood in the art. The inner ring  30  also includes first and second inner ring edge surfaces  36   a ,  36   b  which span the respective exterior and interior cylindrical surfaces  32 ,  34 . 
     The exterior cylindrical surface  32  of the inner ring  30  includes first and second inner ring grooves  38   a ,  38   b . Each of the inner ring grooves  38   a ,  38   b  are inset from the respective first and second outer ring edge surfaces  36   a ,  36   b . That is to say, the first inner ring groove  38   a  is formed in the exterior cylindrical surface  32  at a position that is set in from first edge surface  36   a . Similarly, the second inner ring groove  38   b  is formed in the exterior cylindrical surface  32  at a position that is set in from the second edge surface  36   b . These inner ring grooves  38   a ,  38   b  cooperate with the outer ring grooves  28   a ,  28   b  of the outer ring  20  to retain the present seal body, as will also be explained in detail hereinbelow. 
     The sealed bearing  10  of the present invention also includes a plurality of rolling elements  40  retained between the interior cylindrical surface  24  of the outer ring  20  and the exterior cylindrical surface  32  of the inner ring  30 . These rolling elements  40  provide rolling contact with both the outer ring  20  and the inner ring  30 . Though only a single rolling element  40  is depicted in  FIG. 2 , it is to be appreciated that the plurality of rolling elements  40  are distributed along the entire annular body of the sealed bearing  10 , occupying the volume enclosed by the outer ring  20  and the inner ring  30 , as is understood and appreciated in the art. The plurality of rolling elements  40  can be retained in place against contact with each other using a separator (not shown) or any other such conventional configuration as is known in the art. 
     As particularly shown in  FIG. 2 , an exemplary embodiment of the sealed bearing  10  includes a plurality of rolling elements  40  in the form of bearing balls  40 , having a generally spherical shape. The interior cylindrical surface  24  of the outer ring  20  includes an outer ring ball raceway  42 . Similarly, the exterior cylindrical surface  32  of the inner ring  30  comprises an inner ring ball raceway  44 . These respective raceways  42 ,  44  define contact surfaces to provide and enable the rolling contact between the bearing balls  40  and the outer and inner rings  20 ,  30 . As particularly shown in  FIG. 2 , the respective ball raceways  42 ,  44  are formed as concave surfaces having generally the same shape, size and diameter as the respective bearing balls  40 . It is to be understood and appreciated that the ball raceways  42 ,  44  are generally annular channels or furrows having the corresponding shape, size and diameter as the bearing balls  40 . In this way, the ball raceways  42 ,  44  have a mating relationship to the convex diameter of the plurality of bearing balls. 
     While bearing balls  40  are shown as an exemplary embodiment of the present invention, it is to be understood and appreciated that other types of rolling elements can also be adapted, such as cylindrical roller bearings or needle bearings or the like, all without departing from the present invention. 
     As shown in the side-sectional view of  FIG. 2  and particularly in the close-up, detail view of  FIG. 3 , the present sealed bearing  10  includes first and second seals each composed of a respective first and second seal body  50   a ,  50   b . Each seal body  50   a ,  50   b  is provided for interposition between the outer ring  20  and the inner ring  30  of the sealed bearing  10 . As mentioned hereinabove, each seal body  50   a ,  50   b  is retained between a respective one of the outer ring grooves  28   a ,  28   b  formed on the outer ring  20  and a respective inner ring groove  38   a ,  38   b  formed on the inner ring  30 . That is to say, a first seal composed of a first seal body  50   a  is retained between the first outer ring groove  28   a  and the first inner ring groove  38   a . Similarly, a second seal composed of a second seal body  50   b  is retained between the second outer ring groove  28   b  and the second inner ring groove  38   b.    
     Each seal body  50   a ,  50   b  includes a metal shield portion  52  and a rubber portion  54 . While  FIGS. 2 and 3  especially show the details of the components of the first seal including the first seal body  50   a , it is to be appreciated that the second seal body  50   b  is symmetrically identical and includes corresponding components. The metal shield portion  52  of the first seal body  50   a  can be provided for engaging one of the outer or inner ring grooves  28   a ,  38   a , while the rubber portion  54  can be provided for engaging the respective other of the outer or inner ring grooves  28   a ,  38   a , in order to provide rigid mounting of the first seal body  50   a  of the first seal. 
     As depicted in the exemplary embodiments of the figures, the first and second seals defined by the respective seal bodies  50   a ,  50   b  are generally annular and each thus have an outer diameter and an inner diameter. In a preferred embodiment, the metal shield portion  52  of the first seal defines the outer diameter of the first seal body  50   a  and thus engages the first outer ring groove  28   a . Correspondingly, the rubber portion  54  of the first seal defines the inner diameter of the first seal body  50   a  and thus engages the first inner ring groove  38   a.    
     It is to again be understood and appreciated that, similarly, the second seal body  50   b  of the second seal is respectively configured so that similar components define the outer and inner diameter of the seal body  50   b  and thus respectively engage the second outer and inner ring grooves  28   b ,  38   b . Similar corresponding symmetrically identical components and structures are to be understood for all the descriptions hereinabove and hereinbelow. 
     The rubber portion  54  is molded onto an internal face of the metal shield portion  52 , where the “internal face” is understood to be a surface facing inwardly into in the internal volume of the sealed bearing  10  enclosed by the seal bodies  50   a ,  50   b , toward the rolling elements  40 . In this manner, the rubber portion  54  and the metal shield portion  52  are respective annular portions that are formed into an integral unit to provide a sealing function for the sealed bearing  10 . As particularly shown in  FIGS. 2 and 3 , the rubber portion  54  is molded onto the internal face of the metal shield portion  52  from the first outer ring groove  28   a  and extends beyond the metal shield  52  into the inner ring groove  38   a , for providing tight sealing. 
     The outer ring interior surface  24  also includes first and second outer ring gap surfaces  60   a ,  60   b , each defining the inset between the respective first and second outer ring grooves  28   a ,  28   b  and the respective first and second outer ring edge surfaces  26   a ,  26   b . That is to say, the first outer ring gap surface  60   a  defines the inset between the first outer ring groove  28   a  and the first outer ring edge surface  26   a . Correspondingly, the second outer ring gap surface  60   b  defines the inset between the second outer ring groove  28   b  and the second outer ring edge surface  26   b.    
     As shown especially in  FIG. 2 , the respective outer ring gap surfaces  60   a .  60   b  are offset from the outer ring interior cylindrical surface  24 . In other words, the outer ring gap surfaces  60   a ,  60   b  have a greater annular radius than the annular radius of the outer ring interior cylindrical surface  24 . In this manner, the outer ring gap surfaces  60   a ,  60   b  are configured to receive a first protruding portion of the respective seal body  50   a ,  50   b , as will be explained in detail hereinbelow. 
     The inner ring exterior surface  32  similarly includes first and second inner ring gap surfaces  62   a ,  62   b , each defining the inset between the respective first and second inner ring grooves  38   a ,  38   b  and the respective first and second inner ring edge surfaces  36   a ,  36   b . That is to say, the first inner ring gap surface  62   a  defines the inset between the first inner ring groove  38   a  and the first inner ring edge surface  36   a . Correspondingly, the second inner ring gap surface  62   b  defines the inset between the second inner ring groove  38   b  and the second inner ring edge surface  36   b.    
     As also shown especially in  FIG. 2 , the respective inner ring gap surfaces  62   a ,  62   b  are offset from the inner ring exterior cylindrical surface  32 . In other words, the inner ring gap surfaces  62   a ,  62   b  have a greater annular radius than the annular radius of the inner ring exterior cylindrical surface  32 . In this manner, the inner ring gap surfaces  62   a ,  62   b  are configured to receive a second protruding portion of the respective seal body  50   a ,  50   b , as will be explained in detail hereinbelow. 
     The first and second protruding portions of the seal body  50   a ,  50   b  include a curled end  66  of the metal shield portion  52  (shown particularly in  FIG. 3 ) or a labyrinth seal  64  of the rubber portion  54 , each of which provide additional sealing to the present sealed bearing  10 . Exemplary embodiments are contemplated in which either the labyrinth seal  64  or the curled end  66  can be received in either the outer ring gap surfaces  60   a ,  60   b  or the inner ring gap surfaces  62   a ,  62   b . However, in the preferred embodiment, as shown in the figures, seal  50   a  is configured so that the curled end  66  is received in the outer ring gap surface  60   a  and the labyrinth seal  64  is received in the inner ring gap surface  62   a . In this manner, the metal shield portion  52  with the curled end  66  allows for rigid mounting of the seal body  50   a  and superior protection against external debris damage. 
     As shown especially in  FIG. 2 , the labyrinth seal  64  is an extension of the rubber portion  54  that rests upon the respective inner ring gap surface  62   a . The main body of the rubber portion  54  engages directly in the respective inner ring groove  38   a . In this manner, the rubber portion  54  with the labyrinth seal  64  provides a double layer of sealing 
     As shown especially in  FIG. 3 , the rubber portion  54  includes a tight seal portion  68  interposed between the metal shield portion  52  and the respective outer ring groove  28   a . This tight seal portion  68  is tightly fitted by the pressure of the curled end  66  against the respective gap surface  60   a  and thus provides a secure seal. 
     The present sealed bearing  10  further includes a lubricant such as grease winch maintained around the rolling elements  40  and retained in an internal space between the respective first and second seal bodies  50   a ,  50   b  of the first and second seals. As is to be appreciated, the lubricant reduces friction between the rolling elements  40  and the outer and inner rings  20 ,  30 , as is understood in the art. 
     The present sealed bearing  10  and associated seal bodies  50   a ,  50   b  function as trash guard seals having the combined features of a pressed metal shield along with a synthetic rubber labyrinth seal. The present sealed bearing  10  provides a bearing design with superior protection against external debris damage, improper handling, and/or aggressive installation while also providing improved sealing all around the outer and inner rings  20 ,  30  of the sealed bearing  10 . 
     As provided by the present invention, the metal shield  52  with curled end  66  pressed into the outer ring groove  28   a  allows for rigid mounting and superior protection against external debris damage. The oil-resistant synthetic rubber portion  54  of the seal body  50   a  including the labyrinth seal  64  creates an excellent seal between the inner ring groove  38   a . This labyrinth design between the seal lip and inner ring groove  38   a  creates excellent protection against water intrusion while also preventing lubricant (i.e., grease) from leaving the interior of the bearing, which in turn keeps the bearing running efficiently longer. 
     The sealed bearing  10  of the present invention was tested in various dust chambers, muddy water test, and field testing. The present sealed bearing  10  with the “RSXT” seal design consistently performed 20%-30% longer when compared to a conventional seal design. The sealed bearing  10  of the present invention is especially suitable for lawn movers and similar application where an extreme environment is an issue. 
     Numerous embodiments have been described herein. It will be apparent to those skilled in the art that the above methods and apparatuses may incorporate changes and modifications without departing from the general scope of this invention. It is intended to include all such modifications and alterations in so far as they come within the scope of the appended claims or the equivalents thereof. 
     Having thus described the invention, it is now claimed: