Abstract:
A structurally supported, non-pneumatic wheel is provided. The wheel includes a hub constructed from a polymeric material, which can more readily resist deformation during an impact event and provide improvements in noise generation and manufacturing cost. A plurality of tension-transmitting web elements connect the hub with a compliant, load supporting band.

Description:
PRIORITY STATEMENT 
       [0001]    The present application claims priority to PCT/US14/070812, filed Dec. 17, 2014 in the United States Receiving Office. 
     
    
     FIELD OF THE INVENTION 
       [0002]    The subject matter of the present disclosure relates generally to a structurally supported, non-pneumatic wheel. 
       BACKGROUND OF THE INVENTION 
       [0003]    The pneumatic tire is a known solution for compliance, comfort, mass, and rolling resistance. The pneumatic tire has disadvantages, however, in complexity, the need for maintenance, and susceptibility to damage. A device that improves on pneumatic tire performance could, for example, provide more compliance, better control of stiffness, lower maintenance requirements, and resistance to damage. 
         [0004]    Conventional solid tires, spring tires, and cushion tires, although lacking the need for maintenance and the susceptibility to damage of pneumatic tires, unfortunately lack its performance advantages. In particular, solid and cushion tires typically include a solid rim surrounded by a resilient material layer. These tires rely on compression of the ground-contacting portion of the resilient layer directly under the load for load support. These types of tires can be heavy and stiff and lack the shock absorbing capability of pneumatic tires. 
         [0005]    Other non-pneumatic constructions and their benefits are described in e.g., U.S. Pat. Nos. 6,769,465; 6,994,134; 7,013,939; and 7,201,194. Some non-pneumatic tire constructions propose incorporating a shear band, embodiments of which are described in e.g., U.S. Pat. Nos. 6,769,465 and 7,201,194, which are incorporated herein by reference. Such non-pneumatic tires provide advantages in tire performance without relying upon a gas inflation pressure for support of the loads applied to the tire. 
         [0006]    In one example of a non-pneumatic tire, a compliant band with a ground contacting portion can be connected with a plurality of web elements extending radially from a center element or hub. The hub is constructed of metal, which must be machined or cast. Unfortunately, the hub can be a substantial part of the overall cost of the non-pneumatic tire. 
         [0007]    In addition, the metal hub can present certain performance problems. For example, in the operation of both pneumatic and non-pneumatic tires, the tire may experience an impact event that can cause permanent damage. Such an event may occur when e.g., the tire encounters a curb or other large obstacle at an excessive speed. For the non-pneumatic construction as described above, the metal hub may be permanently deformed. In turn, such deformation can cause a noticeable first harmonic non-uniformity that can be sensed by the driver of the vehicle. 
         [0008]    The metal hub can also be susceptible to transmitting vibrations that generate undesirable noises both inside and outside of the vehicle. The high modulus of the metal structure may more readily transmit vibrations caused by factors such as e.g., asperities in the road or vibrations generated by certain components of the tire during operation. 
         [0009]    Accordingly, a non-pneumatic tire with an improved construction would be useful. More particularly, a non-pneumatic tire that can reduce the cost of construction would be beneficial. A non-pneumatic tire that can reduce or eliminate the susceptibility to certain permanent deformations from an impact event would be advantageous. A non-pneumatic tire that can reduce or eliminate the transmission of certain undesirable vibrations to the vehicle and/or otherwise reduce noise generation would also be useful. 
       SUMMARY OF THE INVENTION 
       [0010]    The present invention provides a structurally supported non-pneumatic wheel. The wheel includes a hub constructed from a polymeric material, which can more readily resist permanent deformation from an impact event. The non-metal construction for the hub also helps minimize the undesirable transmission of vibrations to the vehicle and the generation of noise. By avoiding the manufacture of a metallic hub, savings can be realized in the costs of manufacture of the wheel. Additional objects and advantages of the invention will be set forth in part in the following description, or may be apparent from the description, or may be learned through practice of the invention. 
         [0011]    In one exemplary embodiment, the present invention provides a structurally supported, non-pneumatic wheel defining axial, radial, and circumferential directions. The wheel includes a hub having a cylindrical portion extending along the axial direction between a first end and a second end. The hub defines a mounting surface at the first end of the cylindrical portion. The hub is constructed from a polymeric material. A plurality of fastener inserts are positioned in the hub at the mounting surface. The fastener inserts are spaced apart from each other along the circumferential direction. A compliant, load supporting band is positioned radially outward and concentrically with the hub. A plurality of tension-transmitting web elements extend between the hub and the load supporting band. 
         [0012]    These and other features, aspects and advantages of the present invention will become better understood with reference to the following description and appended claims. The accompanying drawings, which are incorporated in and constitute a part of this specification, illustrate embodiments of the invention and, together with the description, serve to explain the principles of the invention. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0013]    A full and enabling disclosure of the present invention, including the best mode thereof, directed to one of ordinary skill in the art, is set forth in the specification, which makes reference to the appended figures, in which: 
           [0014]      FIG. 1  illustrates a perspective view of an exemplary embodiment of a non-pneumatic wheel of the present invention. 
           [0015]      FIG. 2  illustrates a perspective view of an exemplary sub-assembly of the embodiment of  FIG. 1 . 
           [0016]      FIG. 3  is a perspective view of an exemplary sub-assembly of the embodiment of  FIG. 1 . 
           [0017]      FIG. 4  provides a perspective view of a portion of an exemplary non-pneumatic wheel of the present invention. 
           [0018]      FIG. 5  is a partial cross-sectional view of the exemplary embodiment of  FIG. 1  as viewed along a meridian plane. 
           [0019]      FIG. 6  is partial cross-sectional view of another exemplary embodiment of a non-pneumatic wheel of the present invention as viewed along a meridian plane. 
       
    
    
     DETAILED DESCRIPTION 
       [0020]    For purposes of describing the invention, reference now will be made in detail to embodiments of the invention, one or more examples of which are illustrated in the drawings. Each example is provided by way of explanation of the invention, not limitation of the invention. In fact, it will be apparent to those skilled in the art that various modifications and variations can be made in the present invention without departing from the scope or spirit of the invention. For instance, features illustrated or described as part of one embodiment, can be used with another embodiment to yield a still further embodiment. Thus, it is intended that the present invention covers such modifications and variations as come within the scope of the appended claims and their equivalents. 
         [0021]    As used herein, the following definitions apply: 
         [0022]    “Meridian plane” is a plane within which lies the axis of rotation of the wheel.  FIGS. 5 and 6 , for example, are partial cross-sections of an exemplary non-pneumatic wheel  100  of the present invention taken along a meridian plane. 
         [0023]    “Equatorial plane” or “EP” is a plane perpendicular to the meridian plane that bisects the tire along its center line. 
         [0024]    The “radial direction” or “R” is perpendicular to the axis of rotation of the wheel. 
         [0025]    The “circumferential direction” or “C” follows the circumference of the wheel. 
         [0026]      FIG. 1  provides a perspective view of an exemplary embodiment of a structurally supported, non-pneumatic wheel  100  shown in an assembled state before mounting onto e.g., a vehicle.  FIG. 2  is a perspective view of a subassembly  96  of wheel  100  while  FIG. 3  is a perspective view of an exemplary polymeric hub  120  of non-pneumatic wheel  100 . The present invention is not limited to the particular shape, size, or appearance shown in the figures. As will be understood using the teachings disclosed herein, wheels of other shapes, sizes, and appearances may be used as well. 
         [0027]    Non-pneumatic wheel  100  includes centrally-located wheel center  102  that can be used to connect wheel  100  to a vehicle (In  FIG. 3 , wheel center  102  has been removed). For example, openings  112  are provided for insertion of bolts or other fastening devices to secure wheel  100  to a vehicle. A plurality of spokes  108  extend between a center portion  98  and a mounting ring  110 . Mounting ring  110  is provided with a plurality of openings  114  through which fasteners  94  may be inserted into fastener inserts  124  ( FIG. 3 ) so as to secure wheel center  102  to a hub  120 . For this exemplary embodiment, fasteners  94 , openings  114 , and fastener inserts  124  are uniformly spaced about mounting ring  110 . Wheel center  102  may be constructed e.g., of metal and provided with various aesthetic features. Other materials may be used as well. 
         [0028]    As shown in  FIG. 1 , non-pneumatic wheel  100  include a compliant, load supporting band  104  that is positioned radially outward of polymeric hub  120  and positioned concentrically with hub  120 . A tread  106  may be formed on, or provided as part of, load supporting band  104 . For example, a tread band may be adhered to load supporting band  104 . A plurality of tension-transmitting web elements  116  extend along the radial direction between hub  120  and load supporting band  104 . Web elements  116  may have other shapes and configurations from what is shown in  FIG. 1 . 
         [0029]    By way of example, load supporting band  104  may include a shear band  150  as shown in the partial cross-sectional view of  FIG. 6  taken along a meridian plane of non-pneumatic wheel  100 . For this exemplary embodiment, shear band  150  includes an inner reinforcing band  140 , and outer reinforcing band  144 , and a shear layer  142  positioned therebetween. Shear layer  142  may be constructed e.g. of an elastomeric material such as e.g., natural and synthetic rubbers, polyurethanes, foamed rubbers and polyurethanes, segmented copolyesters, and block co-polymers of nylon. Reinforcing bands  140  and  144  may include reinforcements  146  and  148 , respectively, constructed from e.g., essentially inextensible cord reinforcements embedded in an elastomeric coating. Such reinforcements may include e.g., any of several materials suitable for use as tire belt reinforcements in conventional tires such as monofilaments or cords of steel, aramid or other high modulus textiles. Other constructions and materials may be used as well. 
         [0030]    Returning to  FIG. 1 , compliant band  104  supports loads transmitted to non-pneumatic wheel or tire  100  when e.g., wheel center  102  is mounted onto a vehicle. More particularly, a load transmitted through wheel center  102  is transmitted by tension through web spokes  116  to compliant band  104 . In turn, the annular compliant band  104  acts in a manner similar to an arch and provides a circumferential compression stiffness and a longitudinal bending stiffness in the tire equatorial plane EP sufficiently high to act as a load-supporting member. Under load, the compliant band  104  deforms over a contact area with the ground surface through a mechanism including shear deformation of compliant band  104 . The ability to deform with shear provides a compliant ground contact area that acts similar to that of a pneumatic tire, with similar advantageous results. 
         [0031]    Hub  120  is constructed from a polymeric material. The polymeric material in the present embodiment may be any suitable polymeric material such as e.g., a natural or synthetic rubber, polyurethane, foamed rubber and foamed polyurethane, segmented copolyesters, and block co-polymers of nylon. The use of a polymeric material provides several advantages. For example, as opposed to a metallic construction, the polymeric material used for hub  120  can reduce the transmission of undesirable vibrations to an attached vehicle. Additionally, the generation of undesirable noises associated with a metal hub can be minimized or avoided. Savings in the costs of manufacture can also be achieved by avoiding the use of metal in forming hub  120 . 
         [0032]    Several different exemplary embodiments may be used for polymeric hub  120 . Referring now to  FIGS. 3, 4, and 5 , for this exemplary embodiment hub  120  includes a cylindrical portion  152  that extends along axial direction A between a first end  154  and a second end  156 . As best shown in  FIGS. 4 and 5 , cylindrical portion  152  has a taper or, more particularly, the radial thickness of cylindrical portion decreases from first end  154  to second end  156  along axial direction A. 
         [0033]    Hub  120  defines a mounting surface  128  near first end  154  for the receipt of wheel center  102 . For this embodiment, mounting surface  128  is substantially parallel (e.g., within ±5 degrees) to radial direction R. As shown, fastener inserts  124  extend along axial direction A through mounting surface  128  and into the cylindrical portion  152  of polymeric hub  120 . Outside surface  158  of exemplary fastener insert  124  is provide with a plurality of engagement elements shown here as ribs  160  and grooves  162  that secure fastener insert  124  in the polymeric material used to make hub  120 . Fastener inserts  124  may be e.g., placed into the mold when hub  120  is formed. 
         [0034]    In this exemplary embodiment, fastener inserts  124  include a threaded opening  164  for complementary receipt of fasteners  94 . Other configurations may be used for fastener inserts  124  as well. For example, fastener inserts  124  may be configured as threaded lugs extending along axial direction A for insertion through openings  114  in wheel center  102  and securement with a nut torqued onto each lug. As will be understood by one of skill in the art using the teachings disclosed herein, a variety of configurations may be used for fastener inserts  124  in order to secure wheel center  102 . Such fastener inserts may e.g., extend partially or completely through hub  120  and may include other features for securing the position of fastener inserts in hub  120 . 
         [0035]    Continuing with  FIGS. 4 and 5 , hub  120  defines a shelf  130  at first end  154 . Shelf  130  projects outwardly along axial direction A from first end  154  past mounting surface  128 . As such, shelf  130  forms a notch or groove for receipt of the outer circumferential edge  166  ( FIGS. 1 and 5 ) of wheel center  102 . 
         [0036]    Hub  120  may also define an additional shelf  134  at second end  156 . Shelf  134  projects outwardly along axial direction A from second end  156  past mounting surface  132 . Similar to shelf  130 , shelf  134  forms a notch or groove into which e.g., a ring or other device may be received as will be further described. 
         [0037]    For this exemplary embodiment, the compliant band  104  of non-pneumatic wheel  100  defines a radially inner surface  118  ( FIG. 5 ). An outer interface structure  126  is attached to the radially outer ends  168  of web elements  116  and to radially inner surface  118 . The radially inner ends  170  of web elements  116  are attached directly to the cylindrical portion  152  of hub  120 . In one exemplary aspect of the present invention, outer interface structure  126  is integrally formed with web elements  116  and may also be integrally formed with hub  120 . For example, outer interface structure  126 , web elements  116 , and hub  120  may be cast together in the same mold. In other embodiments of the invention, one or more such elements may be formed separately. 
         [0038]      FIG. 6  provides a partial cross-sectional view of another exemplary embodiment of a structurally supported, non-pneumatic wheel  100 . For this exemplary embodiment, non-pneumatic wheel  100  includes a fastening insert in the form of a pin  124   a  that extends through mounting surface  128 , axially through cylindrical portion  152  of hub  120 , and through additional mounting surface  132 . Pin  124   a  connects wheel center  102  positioned at first end  154  with a ring  138  positioned at second end  156  to secure wheel center  102  onto hub  120 . As shown, in this exemplary embodiment, cylindrical portion  152  does not taper or change thickness along axial direction A. 
         [0039]    The exemplary hub  120  of  FIG. 6  includes an inner interface structure  172  positioned on radially outer mounting surface  122 . Inner interface structure  172  is attached to the radially inner ends  170  of web elements  116  and to radially outer mounting surface  122 . In one exemplary aspect of the present invention, inner interface structure  172  is integrally formed with web elements  116  and may also be integrally formed with hub  120 . For example, inner interface structure  172 , web elements  116 , and hub  120  may be cast together in the same mold. In other embodiments of the invention, one or more such elements may be formed separately. 
         [0040]    While the present subject matter has been described in detail with respect to specific exemplary embodiments and methods thereof, it will be appreciated that those skilled in the art, upon attaining an understanding of the foregoing may readily produce alterations to, variations of, and equivalents to such embodiments. Accordingly, the scope of the present disclosure is by way of example rather than by way of limitation, and the subject disclosure does not preclude inclusion of such modifications, variations and/or additions to the present subject matter as would be readily apparent to one of ordinary skill in the art using the teachings disclosed herein.