Patent Publication Number: US-2023141345-A1

Title: Non-pneumatic tire and wheel assembly

Description:
FIELD OF THE INVENTION 
     The invention relates in general to a vehicle wheel, and more particularly to a nonpneumatic tire and wheel assembly. 
     BACKGROUND OF THE INVENTION 
     The pneumatic tire has been the solution of choice for vehicular mobility for over a century. The pneumatic tire is a tensile structure. The pneumatic tire has at least four characteristics that make the pneumatic tire so dominate today. Pneumatic tires are efficient at carrying loads, because all of the tire structure is involved in carrying the load. Pneumatic tires are also desirable because they have low contact pressure, resulting in lower wear on roads due to the distribution of the load of the vehicle. Pneumatic tires also have low stiffness, which ensures a comfortable ride in a vehicle. The primary drawback to a pneumatic tire is that it requires compressed fluid. A conventional pneumatic tire is rendered useless after a complete loss of inflation pressure. 
     A tire designed to operate without inflation pressure may eliminate many of the problems and compromises associated with a pneumatic tire. Neither pressure maintenance nor pressure monitoring is required. Structurally supported tires such as solid tires or other elastomeric structures to date have not provided the levels of performance required from a conventional pneumatic tire. A structurally supported tire solution that delivers pneumatic tire-like performance would be a desirous improvement. 
     Non-pneumatic tires are typically defined by their load carrying efficiency. “Bottom loaders” are essentially rigid structures that carry a majority of the load in the portion of the structure below the hub. “Top loaders” are designed so that all of the structure is involved in carrying the load. Top loaders thus have a higher load carrying efficiency than bottom loaders, allowing a design that has less mass. 
     Thus, an improved non-pneumatic tire is desired that has all the features of the pneumatic tires without the drawback of the need for air inflation is desired. It is also desired to have an improved nonpneumatic tire that has longer tread life as compared to a pneumatic tire of the same size. 
     SUMMARY OF THE INVENTION 
     The invention provides in a first aspect a nonpneumatic tire and wheel assembly comprising: a wheel, a spoke ring structure having a discontinuous inner ring that is mounted on an outer wheel mounting surface of the wheel, wherein the discontinuous inner ring has one or more gaps, wherein the spoke ring structure has a plurality of spoke members, and an outer tread ring mounted on the outer circumference of the spoke ring. 
     The invention provides in a second aspect a nonpneumatic tire and wheel assembly comprising: a wheel, a spoke ring structure having an inner ring that is mounted on an outer rim mounting surface of the wheel, wherein the spoke ring structure has a plurality of spoke members, and an outer tread ring mounted on the outer circumference of the spoke ring, wherein the wheel is axially recessed within the nonpneumatic tire and wheel assembly. 
     The invention provides in a third aspect a nonpneumatic tire and wheel assembly comprising: a wheel, a spoke ring structure having an inner ring that is mounted on an outer rim mounting surface of the wheel, wherein the spoke ring structure has a plurality of spoke members, and an outer tread ring mounted on the outer circumference of the spoke ring, wherein at least one of the spoke members has an axially outer edge, wherein the axially outer edge is radiused. 
     The invention provides in a fourth aspect a nonpneumatic tire and wheel assembly comprising: a wheel, a spoke ring structure having an inner ring that is mounted on an outer rim mounting surface of the wheel, wherein the spoke ring structure has a plurality of spoke members, and an outer tread ring mounted on the outer circumference of the spoke ring, wherein each spoke member has a radially inner portion and a radially outer portion, wherein the radially inner portion has an axial width less than the radially outer portion. 
     Definitions 
     “Aspect Ratio” means the ratio of a tire&#39;s section height to its section width. 
     “Axial” and “axially” means the lines or directions that are parallel to the axis of rotation of the tire. 
     “Belt Structure” or “Reinforcing Belts” means at least two annular layers or plies of parallel cords, woven or unwoven, underlying the tread, unanchored to the bead, and having both left and right cord angles in the range from 17° to 27° with respect to the equatorial plane of the tire. 
     “Breakers” or “Tire Breakers” means the same as belt or belt structure or reinforcement belts. 
     “Circumferential” means lines or directions extending along the pewheeleter of the surface of the annular tread 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. 
     “Radial” and “radially” mean directions radially toward or away from the axis of rotation of the tire. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       The invention will be described by way of example and with reference to the accompanying drawings in which: 
         FIG.  1    is a front view of a nonpneumatic tire and wheel assembly of the present invention; 
         FIG.  2    is a side perspective view of the nonpneumatic tire and wheel assembly of  FIG.  1   ; 
         FIG.  3 A  is a front view of a spoke ring assembly, while  FIG.  3 B  is a close up perspective view of a portion of the spoke ring assembly of  FIG.  3 A ; 
         FIG.  4 A  is a cross-sectional view of the nonpneumatic tire and wheel assembly,  FIG.  4 B  is close up perspective view of the spoke portion of the wheel of  FIG.  4 A ;  FIG.  4 C  is a cross-sectional perspective view from the right hand side, while  FIG.  4 D  is a cross-sectional perspective view from the left hand side; 
         FIG.  5    is an exploded view of the nonpneumatic tire and wheel assembly of  FIG.  1   ; 
         FIG.  6    is an exploded view of the nonpneumatic tire and wheel assembly of  FIG.  1    with a second embodiment of the hub cover; 
         FIG.  7 A  is a side view of a hub cover,  FIG.  7 B  is a front view of the hub cover, and  FIG.  7 C  is a rear perspective view of the hub cover; and 
         FIGS.  8 A- 8 C  illustrate the nonpneumatic tire and wheel assembly with different diameter hubcap covers. 
     
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
     Referring to  FIGS.  1  through  5   , a nonpneumatic tire and wheel assembly  10  of the present invention is shown. The nonpneumatic tire and wheel assembly  10  includes an outer annular tread ring  30 , a spoke ring  20 , and a wheel  40 . The outer annular tread ring  30  is preferably a one piece annular structure that is formed of a polymer, rubber or other desired elastomer. The tread ring  30  may be molded and cured as a one piece ring, and is mounted on the outer periphery of the spoke ring. The outer tread surface  31  of the tread ring  30  may include tread elements such as ribs, blocks, lugs, grooves, and sipes as desired in order to improve the performance of the tire in various conditions. 
     The tread ring  30  may optionally include one or more layers  32  of reinforced fabric, wherein the reinforced fabric is preferably formed of parallel reinforcement cords. The reinforcement cords may be nylon, polyester or steel. The reinforced fabric layer  32  is preferably coated with rubber for adhesion to the tread. Alternatively, the tread ring may optionally include one or more layers of rubber coated wire that is spirally wound so that it forms an angle of about zero degrees, so that the wire is oriented in the circumferential direction. More preferably, there are at least two layers of reinforced fabric with no spacing in between. 
     Spoke Ring Structure 
     The nonpneumatic tire and wheel assembly  10  further includes a spoke ring structure  20 . The spoke ring structure  20  has an inner portion  22  that is mounted on the wheel rim mounting surface  42 . The inner portion  22  is a discontinuous ring divided into two or more segments with gaps  24  between the segments and along the inner radius to allow for ease of assembly with the wheel. Preferably, the inner portion  22  has an interference fit on the outer rim mounting surface  42  of the wheel  40 . 
     The spoke ring structure further includes an outer ring  26  having an outer surface that is joined to the inner tread surface  34  by an adhesive polymer. The spoke ring structure further includes a plurality of spoke members that extend between an inner portion  22  to the outer ring  26 . In a first example shown in  FIGS.  2  and  7   , the spoke ring structure has a first spoke member  60  that extends from the inner portion  22  to the outer ring  26 , preferably at an angle. The spoke ring structure includes a second spoke member  62  that also extends from the inner portion to the outer ring  26 , preferably at an angle. The first and second spoke member  60 , 62  are joined together at a junction  70  to form an X shaped spoke. The first and second spoke members  60 , 62  may be straight or curved. The number of spokes may vary, for example, from 15 to 30 depending upon the vehicle weight and desired spring rate. 
     As shown in cross-section in  FIG.  4 A , the inner portion  22  of the spoke ring structure  20  is mounted on the outer rim mounting surface  42  of the wheel. The axial thickness of the inner portion of the spoke structure is preferably less than the axial thickness of the outer ring  26 , allowing the wheel to be recessed inwards of the outer ring of the spoke ring structure, as shown in  FIG.  4 B . The spoke ring structure has axially outer edges  23 , 25  that are radiused or scalloped. The radius R of the radiused outer edges may range from 0.5 to 2 in, and more preferably from 1 to 1.5 inches. The scalloped or radiused outer edges allow the wheel to be recessed axially inward of the spoke and tread ring structure. Furthermore, the axial width of a radially outer portion of one or more of the spoke members is greater than the axial width of the radially inner portion of the one or more spoke members. Additionally, it is preferred that there is a single spoke ring structure  20  mounted on the wheel. 
     The spoke ring structure  20  is preferably an integrally formed annular structure preferably made of a resilient and/or moldable polymeric material such as but not limited to, a thermoplastic elastomer, natural rubber, styrene butadiene rubber, polybutadiene rubber or EPDM rubber or a blend of two or more of these materials which can be utilized in either injection molding or compression molding. The material of the spoke ring structure is selected based upon one or more of the following material properties. The tensile (Young&#39;s) modulus of the spoke disk material is preferably in the range of 5 MPa to 100 MPa, and more preferably in the range of 10 MPa to 70 MPa. 
     The wheel  40  is shown in  FIG.  5   , and has an annular outer rim mounting surface  42  for receiving the inner portion  22  of the spoke ring structure  20 . The wheel further includes a recessed inner disk portion  44  having a plurality of bolt holes  43  for connecting the wheel assembly to a vehicle. The inner disk portion  44  is surrounded by an outer flange  46 . The wheel  40  may include an optional hub cover  50 . The hub cover  50  has an outer display surface  52  that can be used to display company logos or designs. The hub cover  50  has an inner surface  56  that has a mounting ring  54  for reception into the recessed inner disk portion. The mounting ring  54  is secured to the inner disk portion by adhesive, or adhesive strips  58  or by hook and loop fastener strips. As shown in  FIGS.  8 A- 8 C , the hub cover may have varying diameters to cover the spoke ring structure. Although not shown, the hub cover may completely cove the spoke ring structure to prevent road debris from clogging the spoke structure.  FIG.  6    illustrates an alternate embodiment of the hub cap structure  60 , wherein the hub cap comprises a flat disk  60  with a removable ring insert  62  that may be secured by adhesion to the flat disk inner surface  62 . The ring insert has retainers  64  which are received within the flange of the wheel and secured thereto by adhesive. 
     In one example, the tire of the present invention is provided on a mobile delivery vehicle. The mobile delivery vehicle has at least three, preferably four or more nonpneumatic tire and wheel assemblies of the present invention, and more particularly, six nonpneumatic tire and wheel assemblies. The tire has an outer rubber tread and a spoke ring structure that is injection molded and formed of a polyurethane material having a tensile modulus of about 20-25 MPA. The spoke ring structure may also be three dimensionally printed. The nonpneumatic tire and wheel of the present invention has a spring rate in the range of 250 to 300 pounds per inch. The nonpneumatic tire and wheel of the present invention has an axial width of about 1.5 inches with 36 X shaped spokes having a radial height of about 1 inch. While the nonpneumatic tire and wheel assembly is described as having X shaped spokes, other spoke designs could be used. The wheel has an outer diameter of about 5 inches, but could be sized to be smaller in the outer diameter to provide a greater radial height of the spoke ring structure. The weight of the tire is 570 grams and is designed for a minimum tread life of 5000 km, preferably 20,000 km or more. 
     Variations in the present invention are possible in light of the description of it provided herein. While certain representative embodiments and details have been shown for the purpose of illustrating the subject invention, it will be apparent to those skilled in this art that various changes and modifications can be made therein without departing from the scope of the subject invention. It is, therefore, to be understood that changes can be made in the particular embodiments described which will be within the full intended scope of the invention as defined by the following appended claims.