Patent Description:
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 non-pneumatic tire that has longer tread life as compared to a pneumatic tire of the same size.

Non-pneumatic tire and wheel assemblies comprising a radially inner wheel structure and a spoke ring structure having an inner ring that is mounted on a radially outer wheel structure mounting surface of the wheel structure, wherein the spoke ring structure has a plurality of spoke members and wherein a radially outer tread ring is mounted on the outer circumference of the spoke ring structure are known from <CIT>, <CIT>, <CIT>, <CIT>, <CIT> and <CIT>. Such assemblies are also described in <CIT> and <CIT>, which are published only after the priority date of this application.

The invention relates to a non-pneumatic tire and wheel assembly in accordance with claim <NUM> and to a method in accordance with claim <NUM>.

A non-pneumatic tire and wheel assembly is disclosed comprising a radially inner wheel structure, a spoke ring structure having an inner ring that is mounted on a radially outer wheel structure mounting surface of the wheel structure, wherein the spoke ring structure has a plurality of spoke members, and a radially outer tread ring mounted on the outer circumference of the spoke ring structure. The non-pneumatic tire and wheel assembly has at least one or any combination of the following features:.

The invention provides in a first preferred aspect a non-pneumatic 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 spoke ring structure includes a radially outer ring having an outer surface that is joined to a radially inner surface of the tread ring by an adhesive polymer. The inner ring is attached to the radially outer wheel structure mounting surface of the wheel structure via an interference fit.

The invention provides in a second preferred aspect a non-pneumatic 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 non-pneumatic tire and wheel assembly. The spoke ring structure includes a radially outer ring having an outer surface that is joined to a radially inner surface of the tread ring by an adhesive polymer. The inner ring is attached to the radially outer wheel structure mounting surface of the wheel structure via an interference fit.

The invention provides in a third preferred aspect a non-pneumatic 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 spoke ring structure includes a radially outer ring having an outer surface that is joined to a radially inner surface of the tread ring by an adhesive polymer. The inner ring is attached to the radially outer wheel structure mounting surface of the wheel structure via an interference fit.

The invention provides in a fourth preferred aspect a non-pneumatic 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. The spoke ring structure includes a radially outer ring having an outer surface that is joined to a radially inner surface of the tread ring by an adhesive polymer. The inner ring is attached to the radially outer wheel structure mounting surface of the wheel structure via an interference fit.

"Aspect Ratio" means the ratio of a tire'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 <NUM>° to <NUM>° 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.

Referring to <FIG>, a non-pneumatic tire and wheel assembly <NUM> of the present invention is shown. The non-pneumatic tire and wheel assembly <NUM> includes an outer annular tread ring <NUM>, a spoke ring <NUM>, and a wheel <NUM>. The outer annular tread ring <NUM> is preferably a one-piece annular structure that is formed of a polymer, rubber or other desired elastomer. The tread ring <NUM> 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 <NUM> of the tread ring <NUM> 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 <NUM> preferably includes one or more layers <NUM> of reinforced fabric, wherein the reinforced fabric is preferably formed of parallel reinforcement cords. The reinforcement cords are preferably nylon, polyester or steel. The reinforced fabric layer <NUM> is preferably coated with rubber for adhesion to the tread. Alternatively, the tread ring may include one or more layers of rubber coated wire that is preferably spirally wound so that it forms an angle of about zero degrees or in a range of from <NUM> to <NUM> degrees or <NUM> to <NUM> 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.

The non-pneumatic tire and wheel assembly <NUM> further includes a spoke ring structure <NUM>. The spoke ring structure <NUM> has an inner portion <NUM> that is mounted on the wheel rim mounting surface <NUM>. The inner portion <NUM> is a discontinuous ring divided into two or more segments with gaps <NUM> between the segments and along the inner radius to allow for ease of assembly with the wheel. The inner portion <NUM> has an interference fit on the outer rim mounting surface <NUM> of the wheel <NUM>.

The spoke ring structure further includes an outer ring <NUM> having an outer surface that is joined to the inner tread surface <NUM> by an adhesive polymer. The spoke ring structure further includes a plurality of spoke members that extend between an inner portion <NUM> to the outer ring <NUM>. In a first example shown in <FIG> and <FIG>, the spoke ring structure has a first spoke member <NUM> that extends from the inner portion <NUM> to the outer ring <NUM>, preferably at an angle. The spoke ring structure includes a second spoke member <NUM> that also extends from the inner portion to the outer ring <NUM>, preferably at an angle. The first and second spoke member <NUM>, <NUM> are joined together at a junction <NUM> to form an X shaped spoke. The first and second spoke members <NUM>, <NUM> may be straight or curved. The number of spokes may vary, preferably from <NUM> to <NUM>, depending upon the vehicle weight and desired spring rate.

As shown in cross-section in <FIG>, the inner portion <NUM> of the spoke ring structure <NUM> is mounted on the outer rim mounting surface <NUM> 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 <NUM>, allowing the wheel to be recessed inwards of the outer ring of the spoke ring structure, as shown in <FIG>. The spoke ring structure has axially outer edges <NUM>, <NUM> that are radiused or scalloped. The radius R of the radiused outer edges preferably range from <NUM> to <NUM>, and more preferably from <NUM> to <NUM>. 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 <NUM> mounted on the wheel.

The spoke ring structure <NUM> is preferably an integrally formed annular structure preferably made of a resilient and/or moldable polymeric material such as 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's) modulus of the spoke disk material is preferably in the range of from <NUM> MPa to <NUM> MPa, and more preferably in the range of from <NUM> MPa to <NUM> MPa.

The wheel <NUM> is shown in <FIG> and has an annular outer rim mounting surface <NUM> for receiving the inner portion <NUM> of the spoke ring structure <NUM>. The wheel further includes a recessed inner disk portion <NUM> having a plurality of bolt holes <NUM> for connecting the wheel assembly to a vehicle. The inner disk portion <NUM> is surrounded by an outer flange <NUM>. The wheel <NUM> may include an optional hub cover <NUM>. The hub cover <NUM> has an outer display surface <NUM> that can be used to display company logos or designs. The hub cover <NUM> has an inner surface <NUM> that has a mounting ring <NUM> for reception into the recessed inner disk portion. The mounting ring <NUM> is secured to the inner disk portion by adhesive, or adhesive strips <NUM> or by hook and loop fastener strips. As shown in <FIG>, the hub cover may have varying diameters to cover the spoke ring structure <NUM>. Although not shown, the hub cover preferably completely covers the spoke ring structure to prevent road debris from clogging the spoke structure. <FIG> illustrates an alternate embodiment of the hub cap structure <NUM>, wherein the hub cap comprises a flat disk <NUM> with a removable ring insert <NUM> that may be secured by adhesion to the flat disk inner surface <NUM>. The ring insert has retainers <NUM> which are received within the flange of the wheel and secured thereto by adhesive.

Claim 1:
A non-pneumatic tire and wheel assembly comprising a radially inner wheel structure (<NUM>), a spoke ring structure (<NUM>) having an inner ring (<NUM>) that is mounted on a radially outer wheel structure mounting surface (<NUM>) of the wheel structure (<NUM>), wherein the spoke ring structure (<NUM>) has a plurality of spoke members (<NUM>, <NUM>), and a radially outer tread ring (<NUM>) mounted on the outer circumference of the spoke ring structure (<NUM>), wherein the spoke ring structure (<NUM>) includes a radially outer ring (<NUM>) having an outer surface that is joined to a radially inner surface (<NUM>) of the tread ring (<NUM>) by an adhesive polymer and wherein the inner ring (<NUM>) is attached to the radially outer wheel structure mounting surface (<NUM>) of the wheel structure (<NUM>) via an interference fit; and wherein the non-pneumatic tire and wheel assembly (<NUM>) further has at least one or any combination of the following features:
a) the inner ring (<NUM>) is a discontinuous inner ring (<NUM>) having one or more gaps between inner ring segments (<NUM>);
b) the radially inner wheel structure (<NUM>) is axially recessed within the non-pneumatic tire and wheel assembly (<NUM>) with respect to the maximum axial width of the spoke ring structure (<NUM>) and/or the tread ring (<NUM>),
c) at least one or all of the spoke members (<NUM>, <NUM>) has/have an axially outer edge (<NUM>, <NUM>) that is radiused or scalloped;
d) each spoke member (<NUM>, <NUM>) 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.