Patent Publication Number: US-2023144443-A1

Title: Wheel for a support structure

Description:
FIELD OF INVENTION 
     The present invention relates to wheel/tire assemblies, and more particularly, to non-pneumatic wheel/tire assemblies. 
     BACKGROUND OF THE INVENTION 
     Radial pneumatic tires rely on the ply reinforcement to carry and transfer the load between the rim and the belt layer. These ply cords need to be tensioned to carry the load. Tensioning of these ply cords is achieved with the pressurized air in the inner chamber of the tire. If air pressure is lost, load carrying capacity of a pneumatic tire decreases significantly. Preventing the slow or sudden air pressure loss has been a challenge for the tire makers. One proposed solution is to use non-pneumatic tires. A top loader non-pneumatic tire can perform similar to a pneumatic tire if its durability, speed rating/limit and load capacity can be increased to the levels of a pneumatic tire. 
     Many top loader non-pneumatic tires rely on the polymeric spokes to carry the load of the vehicle. Spokes transfer the load from the rim to the shear band. Due to the characteristics of the polymeric materials used in the spokes of these tires, adjustment of the spoke tension provides a variable performance range for the tire assembly. It is an object of the present invention to allow adjustability of the spoke tension and hence performance tunability of the tire per the desired application, expanding the versatility of a single non-pneumatic tire construction. 
     DEFINITIONS 
     As used herein and in the claims: 
     “Annular” means formed like a ring. 
     “Axial” and “axially” refer to lines or directions that are parallel to the axis of rotation of the tire. 
     “Circumferential” and “circumferentially” mean lines or directions extending along the perimeter of the surface of the annular tire parallel to the equatorial plane (EP) and perpendicular to the axial direction; it can also refer to the direction of the sets of adjacent circular curves whose radii define the axial curvature of the tread, as viewed in cross section. 
     “Cut shearband ply” refers to a shearband having a width less than the tread width, which lies flat over the carcass plies in the crown area of the tire. 
     “Crown” means that portion of the tire in the proximity of the tire tread. 
     “Elastomer” means a resilient material capable of recovering size and shape after deformation. 
     “Equatorial plane (EP)” means the plane perpendicular to the tire&#39;s axis of rotation and passing through the center of its tread; or the plane containing the circumferential centerline of the tread. 
     “Evolving tread pattern” means a tread pattern, the running surface of which, which is intended to be in contact with the road, evolves with the wear of the tread resulting from the travel of the tire against a road surface, the evolution being predetermined at the time of designing the tire, so as to obtain adhesion and road handling performances which remain substantially unchanged during the entire period of use/wear of the tire, no matter the degree of wear of the tread. 
     “Footprint” means the contact patch or area of contact of the tire tread with a flat surface at zero speed and under normal load and pressure. 
     “Inner” means toward the inside of the tire and “outer” means toward its exterior. 
     “Inboard side” means the side of the tire nearest the vehicle when the tire is mounted on a wheel and the wheel is mounted on the vehicle. 
     “Lateral” means an axial direction. 
     “Load range” means load and inflation limits for a given tire used in a specific type of service as defined by tables in The Tire and Rim Association, Inc. 
     “Net contact area” means the total area of ground contacting elements between defined boundary edges as measured around the entire circumference of the tread. 
     “Normal load” means the specific design inflation pressure and load assigned by the appropriate standards organization for the service condition for the tire. 
     “Outboard side” means the side of the tire farthest away from the vehicle when the tire is mounted on a wheel and the wheel is mounted on the vehicle. 
     “Radial” and “radially” mean directions radially toward or away from the axis of rotation of the tire. 
     “Self-supporting run-flat” means a type of tire that has a structure wherein the tire structure alone is sufficiently strong to support the vehicle load when the tire is operated in the uninflated condition for limited periods of time and limited speed. The sidewall and internal surfaces of the tire may not collapse or buckle onto themselves due to the tire structure alone (e.g., no internal structures). 
     “Sidewall” means that portion of a tire radially between the tread and the bead. 
     “Spring rate” means the stiffness of tire expressed as the slope of the load deflection curve at a given pressure. 
     “Stiffness ratio” means the value of a control shearband structure stiffness divided by the value of another shearband structure stiffness when the values are determined by a fixed three point bending test having both ends of the cord supported and flexed by a load centered between the fixed ends. 
     “Tensile stress” is force expressed in force/cross-sectional area. Strength in psi=12,800 times specific gravity times tenacity in grams per denier. 
     “Tension” for a cord means force on the cord expressed as mN/tex. 
     “Tread” means a molded rubber component which, when bonded to a tire casing, includes that portion of the tire that comes into contact with the road when the tire is normally inflated and under normal load. 
     “Tread width” means the arc length of the tread surface in a plane including the axis of rotation of the tire. 
     “Vertical deflection” means the amount that a tire deflects under load. 
     SUMMARY OF THE INVENTION 
     A wheel assembly for a tire, in accordance with the present invention, includes a circular hub member for securing to a rotatable axle of a vehicle, an annular first rim piece for engaging the tire, the first rim piece being secured to a first axial end of the circular hub member, an annular second rim piece for engaging the tire, the second rim piece being secured to an opposite second axial end of the circular hub member, a plurality of cylindrical bolts for engaging both the first rim piece and the second rim piece, the cylindrical bolts each engaging the first rim piece, the second rim piece, and a spoke structure of the tire; and a threaded tension bolt for varying a radial position of a first axial end of one of the cylindrical bolts relative to a first elongate opening of the first rim piece. 
     According to another aspect of the wheel assembly, the first rim piece has an axially extending cylindrical first rim flange. 
     According to still another aspect of the wheel assembly, the second rim piece has an axially extending cylindrical second rim flange. 
     According to yet another aspect of the wheel assembly, each of the first elongate openings of the first rim piece are axially aligned with corresponding second elongate openings of the second rim piece. 
     According to still another aspect of the wheel assembly, each of the cylindrical bolts has a radially outer surface for engaging corresponding loops of the tire. 
     According to yet another aspect of the wheel assembly, each corresponding pair of first and second elongate openings are radially and circumferentially secured and fixed in axially aligned relative positions by one of the cylindrical bolts and a corresponding threaded tension bolt. 
     According to still another aspect of the wheel assembly, a radial adjustment assembly includes the threaded tension bolt, a load collar for applying a measured external load to the cylindrical bolts (for spoke tension adjustability), and a lock nut for fixedly securing the tension bolt to a first axial end of one of the cylindrical bolts. Alternatively, a radial adjustment assembly includes the threaded tension bolt, a torque sleeve for aligning the first and second rim pieces and the cylindrical bolts, and a lock nut for fixedly securing the tension bolt to a first axial end of one of the cylindrical bolts. 
     According to yet another aspect of the wheel assembly, the tension bolts are threadedly adjusted to vary a radial position of the first axial end of one of the cylindrical bolts relative to the first elongate opening of the first rim piece. 
     According to still another aspect of the wheel assembly, the first and second rim pieces are constructed of a metal. 
     According to yet another aspect of the wheel assembly, the first and second rim pieces are constructed of a polymer. 
     A method in accordance with the present invention supports a vehicle load. The method includes the steps of: axially engaging first ends of cylindrical bolts with a first rim piece; axially engaging second ends of the cylindrical bolts with a second rim piece; axially and radially engaging loop members of a tire assembly by outer cylindrical surfaces of the cylindrical bolts; inserting one axial end of each cylindrical bolt through a first elongate opening in the first rim piece; and inserting an opposite axial end of each cylindrical bolt through a corresponding second elongate opening in the second rim piece. 
     According to another aspect of the method, a further step includes axially securing a plurality of tension bolts to each opposite axial end of the cylindrical bolts. 
     According to still another aspect of the method, a further step includes securing a circular hub member to the first rim piece thereby allowing rotational attachment to a vehicle. 
     According to yet another aspect of the method, a further step includes arraying a plurality of first elongate openings circumferentially about the first rim piece. 
     According to still another aspect of the method, a further step includes arraying a plurality of second elongate openings circumferentially about the second rim piece. 
     According to yet another aspect of the method, a further step includes radially and circumferentially fixing the first rim piece to the second rim piece in axially aligned relative positions by the cylindrical bolts and a tension bolt. 
     According to still another aspect of the method, a further step includes engaging a cylindrical outer surface of each of the cylindrical bolts by a corresponding loop of a tire. 
     According to yet another aspect of the method, a further step includes permanently securing a tension bolt to each opposite end of the cylindrical bolts. 
     According to still another aspect of the method, a further step includes adjusting tension in loops of a tire by radially varying each axial end of each cylindrical bolt. 
     According to yet another aspect of the method, a further step includes maintaining flat contact between a loop of a tire and a semi-cylindrical retainer. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       The present invention will be more clearly understood by the following description of some examples thereof, with reference to the accompanying drawings, in which: 
         FIG.  1    is a schematic perspective view of an example wheel assembly in accordance with the present invention; 
         FIG.  2    is another schematic perspective view of a first part of the example wheel assembly of  FIG.  1   ; 
         FIG.  3    is still another schematic perspective view of a second part of the example wheel assembly of  FIG.  1   ; 
         FIG.  4    is yet another schematic perspective view of a third part of the example wheel assembly of  FIG.  1   ; 
         FIG.  5    is still another schematic perspective view of a fourth part of the example wheel assembly of  FIG.  1   ; 
         FIG.  6    is a detailed schematic perspective view of a fifth part of the example wheel assembly of  FIG.  1   ; 
         FIG.  7    is another detailed schematic perspective view of the fifth part of the wheel assembly of  FIG.  6   ; 
         FIG.  8    is a schematic perspective view of an example tire for use with the example wheel assembly of  FIG.  1   ; and 
         FIG.  9    is a detailed schematic perspective view of a junction between the wheel assembly of  FIG.  1    and the example tire of  FIG.  8   . 
     
    
    
     DESCRIPTION OF EXAMPLES OF THE PRESENT INVENTION 
     A conventional wheel/tire assembly may have an outer ring, such as a shear band, flexibly connected to a central hub by means of lightweight composite springs. The springs may be plates fixed to the ring and to the hub. The hub may contain a speed reduction gear unit and/or an electric motor and may have a suspension mechanism for connecting a vehicle chassis to each wheel. The ring may be constructed from a flexible composite material, such as carbon fiber reinforced nylon material and have twin rubber tires and a plurality of circumferentially spaced-apart radial cleats which engage the ground and provide improved traction. The hub may also be formed from a carbon fiber reinforced composite material. Another conventional wheel may have a rubber strip with a molded tread bonded to a composite ring for improved grip. Further, the springs interconnecting the ring and hub may be S-shaped lightweight composite springs. 
     Another conventional wheel/tire assembly may be formed from a lightweight composite material, such as carbon fiber reinforced polyamide. The assembly may have a cylindrical central hub and a circular outer flexible rim mounted on the central hub by an endless looped spring band extending between the central hub and the circular rim. Six radial loops may be defined by the spring band. The spring band may be attached to the central hub and to the circular rim by any suitable means, such as adhesion, cohesion, soldering and/or mechanical fixing by means of bolts, rivets, and/or clamps. 
     An example wheel/tire assembly, such as that described in Applicant&#39;s U.S. Pat. Nos. 10,207,544 and 10,603,956, both incorporated herein by reference in their entirety, may be formed from a lightweight polymer material, such as, for example, a standard tire rubber compound, a thermoplastic polymer, polyethylene terephthalate (PET), polyether ether ketone (PEEK), a cross-linking polymer like natural rubber, synthetic rubber-like polymers, epoxy resins, and/or phenolic resins. The assembly may have an inner central rim, such as an automobile wheel (not shown), and a circular outer flexible ring, which may include a shear band and tread structure, mounted on the inner central rim by a continuous cord/fabric reinforced spoke structure extending between the inner central rim and the outer ring. 
     The spoke structure may define a plurality of cavities disposed concentrically about the inner central rim allowing the spoke structure to deflect under load thereby defining a suitable balance between flexibility for ride comfort and traction within a footprint of the assembly and stiffness for vehicle handling, low rolling resistance, and low heat build-up within the spoke structure. The cavities of the spoke structure may further define openings for arms of the inner central rim to extend therethrough and secure the spoke structure to the inner central rim. The arms may engage portions in a mechanical interlocking arrangement. The inner central rim may further include plates that, along with the arms may sandwich the portions of the spoke structure and create a further frictional and/or adhesive securement between the inner central rim and the spoke structure. The spoke structure may comprise a homogenous or heterogeneous polymer and/or a filled polymer. 
     Spokes of the spoke structure may be curved inwardly or outwardly for mitigating or enhancing buckling of the spokes. The spokes may include one or more reinforcing layers. The layer(s) may be constructed of single end dipped cords, conventional pneumatic tire ply/cord arrangements, short fibers, and/or polymeric film. Further, these constructions may be PET, nylon 6, nylon 6,6, rayon, steel, glass fibers, carbon fiber, aramid, and/or a hybrid construction of these materials. The cords may be from 400 denier to 9000 denier. The polymeric film may be from 0.1 mm to 2.0 mm thick. The spokes may be oriented at angle between 0 degrees and 90 degrees. The reinforcement of the spokes may be continuously reinforced across their entire axial length. Continuous reinforcement layer(s) may extend radially outward to multiple locations adjacent to a shear band at the outer flexible ring. 
     Each cavity may have a common cross-sectional profile about the axis of rotation of the assembly. Further, each cavity may have a common axial length equal to a uniform axial thickness of the spoke structure. Each cavity may be curvedly shaped to prevent “pinch” points on the reinforcement layer(s) and mitigate compressive stress concentrations on the reinforcement layer(s). The number of cavities may be between 2 and 60 for large scale tire assemblies. The inner central rim may include steel, cast iron, aluminum, aluminum alloys, magnesium allows, and/or iron alloys. 
       FIGS.  1  through  9    show a wheel assembly  200  in accordance with the present invention for use with pneumatic and/or non-pneumatic tire assemblies, such as the example tire assembly in  FIG.  8    and as described above. The wheel assembly  200  may include a first annular rim piece  210  and a second axially opposite second annular rim piece  220 . Both rim pieces  210 ,  220  may be secured to a circular hub member  230  and thereby secured to a rotatable axle or similar structure of a vehicle (not shown). The first and second rim pieces  210 ,  220  may be constructed of any suitable material, such as metal, polymer, ceramic, and/or a combination thereof. 
     The first rim piece  210  may have an axially extending cylindrical first rim flange  212  and the second rim piece  220  may have an axially extending cylindrical second rim flange (not shown). The first rim piece  210  may further have a plurality of axially extending first elongate openings  214  each for engaging a first axial end  241  of a corresponding axially extending cylindrical bolt  240 . The second rim piece  220  may further have a plurality of axially extending second elongate openings  224  each for engaging a second opposite axial end  242  of the corresponding cylindrical bolt  240 . The cylindrical bolts  240  may each have radially outer surfaces  245  for engaging corresponding loops  111  of a spoke structure  110  of an example tire assembly  140 . 
     Once these elements  140 ,  210 ,  220 ,  230  have been assembled, each first elongate opening  214  of the first rim piece  210  may align axially with a corresponding second elongate opening  224  of the second rim piece  220  ( FIG.  1   ). Each corresponding pair of elongate openings  214 ,  224  of each rim piece  210 ,  220  may be radially and circumferentially secured and fixed in these aligned relative positions by the cylindrical bolts  240  and corresponding fastener assemblies  250  at both ends  214 ,  224  of the cylindrical bolts. 
     As shown in  FIGS.  6  and  7   , each fastener assembly  250  may include a load collar, or torque sleeve,  251  for applying a measured external load to the cylindrical bolts  240 , a radially extending threaded tension bolt  252  threadedly secured to the cylindrical rim flange  212  and an axial end  241  or  242  of a cylindrical bolt  240 , and a lock nut  254  for fixedly securing the tension bolt  252  and the axial end  241  or  242  of the cylindrical bolt  240 . The tension bolts  252  may be threadedly adjusted (loosened or tightened) to vary a radial position of the axial end  241  or  242  relative to the elongate opening  214  or  224  prior to the locknut  254  being threadedly secured permanently to the axial end  241  or  242  of the cylindrical bolt  240 . Thus, tension in the loops  111  of the spoke structure  110  of the tire assembly  140  may be individually radially adjusted at each axial end  241  or  242  of each cylindrical bolt  240  by each fastener assembly  250 . 
     As shown in  FIGS.  5  and  9   , a retainer assembly  270  may include: a semi-cylindrical retainer  271  for maintaining flat contact between each loop  111  of the tire  140  and each cylindrical bolt  240 ; and two or more cotter pins  272  for radially securing each loop  111  sandwiched between the retainer  271  and the radially outer surface  245  of each cylindrical bolt  240 . The retainers  271  thereby maintain positive, flat contact between the loops  111  and cylindrical bolts  240  when the loops  111  are slackened by a footprint area of the tire  140  during rotation and under load. This constant flat and sandwiched contact between the loops  111  and the retainers  271  also mitigates rubbing/creasing/tearing of the loops  111  over many rotations of the tire  140  under load. 
     The above described radial adjustment of the cylindrical bolts  240  relative to the rim pieces  210 ,  220  may thus enable fine-tuning of the performance stiffness of the spoke structure  110  of the tire  140  on the fly (e.g., increase connecting structure tension for a pre-loaded condition, remove tension rods to reduce the number of engaged connecting structure loops, etc.). Such stiffness adjustment allows use of identical tires for multiple requirement and purposes. 
     Variations in the present invention are possible in light of the description of it provided herein. While certain representative examples and details have been shown for the purpose of illustrating the present invention, it will be apparent to those skilled in this art that various changes and/or modifications may be made therein without departing from the scope of the present invention. It is, therefore, to be understood that changes may be made in the particular examples described herein, which will be within the full scope of the present invention as defined by the following appended claims. Further, the present invention is not limited to the examples hereinbefore described, which may be varied in construction and/or detail within the full scope of the appended claims.