Patent Description:
Various tire constructions have been developed which enable a tire to run in an uninflated or underinflated condition. Non-pneumatic tires do not require inflation, while "run flat tires" may continue to operate after receiving a puncture and a complete or partial loss of pressurized air, for extended periods of time and at relatively high speeds. Non-pneumatic tires may include a plurality of spokes, a webbing, or other support structure that connects an inner ring to an outer ring. In some non-pneumatic tires, a circumferential tread may be wrapped about the outer ring of the tire. The circumferential tread may contain a shear element having an elastic region disposed between upper and lower inelastic regions.

According to its abstract, <CIT> describes a tire having an annular body of resilient elastomeric material with an outer member at the outer periphery which may carry a tread and an inner member at the inner periphery for mounting on a wheel rim. The inner member is supported and cushioned by a plurality of circumferentially spaced-apart wall members extending from the inner member to the outer member. The annular body may have one or more supporting rings and the wall members of adjacent rings as well as the wall members of the same ring may be offset circumferentially of the tire. The wall members provide a lateral spring rate and a variable radial spring rate across the tread of the tire. The wall members, tread, inner member and outer member may be reinforced by cords extending at bias angles or generally circumferentially of the tire. Sidewalls between the inner and outer members may also be provided for low pressure inflation and exclusion of foreign matter from the spaces between the wall members.

According to its abstract, <CIT> describes a non-pneumatic tire that comprises a spoke structure in which an outer circumferential wheel and an inner circumferential wheel coaxially arranged are connected via a plurality of fins arranged in the circumferential direction with a space therebetween, and a tread ring attached to the outer circumferential side of the spoke structure. A wire is embedded in the outer circumferential wheel of the spoke structure so as to be across at least between a pair of adjacent fins.

According to its abstract, <CIT> describes a non-pneumatic tire that includes the support structure for supporting the load from the vehicle, and the tread layer adjacently arranged on the outer peripheral side of the support structure. The support structure has an inside annular part, an outside annular part arranged in a concentric circular shape outside the inside annular part, and a plurality of connecting parts joined to the inside annular part and the outside annular part and connecting both. The outside annular part is constituted of a first annular layer, and a second annular layer laminated on the outer peripheral side of the first annular layer and lower in a modulus than the first annular layer. The tread layer is constituted of a first tread layer, and a second tread layer laminated on the inner peripheral side of the first tread layer and higher in the modulus than the first tread layer.

According to its abstract, <CIT> describes a non-pneumatic tire that includes: a support structure having an inside annular part, an outside annular part arranged in a concentrically circular shape outside the inside annular part and a plurality of connecting parts and for connecting the inside annular part and the outside annular part and respectively independent in the peripheral direction, and supporting a load from a vehicle; and an air sac arranged outside the support structure, and having a skin part forming a flat doughnut shape in the tire axial direction and a hollow part formed so that air can be filled inside the skin part.

According to its abstract, <CIT> describes a plurality of through holes that are formed in a tire circumferential direction of an annular tread buried with belt layers comprising a steel cord, the belt layers are arranged so as to be left from the through holes in a tire width direction, and a reinforcement layer comprising a resin cord extending in the tire width direction is arranged separately from the belt layers.

Described herein is a non-pneumatic tire that includes an inner ring having an axis of rotation and an outer ring having a plurality of circumferential reinforcements. The non-pneumatic tire further includes support structure extending from the inner ring to the outer ring. The non-pneumatic tire also includes a circumferential tread extending about the outer ring. The circumferential tread includes a tread reinforcement layer spaced from a bottom of the circumferential tread.

Also described herein is a method of making a non-pneumatic tire that includes providing a tire structure having an inner ring, an outer ring, and a plurality of support structures extending between the inner ring and the outer ring. The method further includes providing a thermoplastic sheet having reinforcement cords embedded therein, and attaching the thermoplastic sheet to the outer ring of the tire structure. The method also includes forming a circumferential tread having a reinforcement layer spaced from a bottom surface, and attaching the circumferential tread to the thermoplastic sheet.

Also described herein is a shear structure for a non-pneumatic tire includes a thermoplastic hoop having reinforcement cords embedded therein. The shear structure also includes a first layer of elastomeric material disposed about the thermoplastic hoop, a reinforcement layer disposed about the first layer of elastomeric material, and a second layer of elastomeric material disposed about the reinforcement layer.

<FIG> illustrate one embodiment of a non-pneumatic tire <NUM>. The non-pneumatic tire <NUM> is merely an exemplary illustration and is not intended to be limiting. In the illustrated embodiment, the non-pneumatic tire <NUM> includes a generally annular inner ring <NUM> that engages a rim (not shown) to which the tire <NUM> is mounted. The generally annular inner ring <NUM> has an internal surface <NUM> and an external surface <NUM> and can be made of an elastomeric material or metal.

The non-pneumatic tire <NUM> further includes a generally annular outer ring <NUM> surrounding an interconnected web <NUM>, which is a support structure connected to the generally annular inner ring <NUM>. In alternative embodiments, a plurality of spokes or other support structure connects the inner ring to the outer ring. The outer ring <NUM> can be configured to deform in an area <NUM> around and including a footprint region <NUM> (see <FIG>), which decreases vibration and increases ride comfort.

In one embodiment, the generally annular inner ring <NUM> and the generally annular outer ring <NUM> are made of the same material as interconnected web <NUM>. In an alternative embodiment, at least one of the generally annular inner ring, the generally annular outer ring, and the interconnected web are made of a different material. As shown in <FIG>, the generally annular outer ring <NUM> can have a radially external surface <NUM> to which a tread carrying layer <NUM> is attached. Attachment can be done adhesively or using other methods commonly available in the art.

In the illustrated embodiment, the interconnected web <NUM> has at least two radially adjacent layers <NUM>, <NUM> of web elements <NUM> that define a plurality of generally polygonal openings <NUM>. In other embodiments (not shown), other web configurations may be employed. In another embodiment (not shown), spokes or other support structure may be employed instead of a web.

<FIG> illustrates a front view of another embodiment of a tire structure <NUM> for a non-pneumatic tire. The tire structure <NUM> has a generally annular inner ring <NUM>, a generally annular outer ring <NUM>, and support structure in the form of an interconnected web extending between the inner ring <NUM> and the outer ring <NUM>. The interconnected web is formed by a plurality of web elements <NUM> that define polygonal openings. In this particular embodiment, the web elements <NUM> form a plurality of hexagonal and substantially trapezoidal shapes, including an outer series of alternating hexagonal and trapezoidal opening and an inner series of alternating hexagonal and trapezoidal openings.

<FIG> is a front view of an exemplary tire structure <NUM> for a non-pneumatic tire not forming part of the present invention. The tire structure <NUM> has a generally annular inner ring <NUM>, a generally annular outer ring <NUM>, and support structure in the form of spokes <NUM> extending between the inner ring <NUM> and the outer ring <NUM>. In the illustrated embodiment, <NUM> radially extending, linear spokes are shown. However, it should be understood that any number of spokes may be employed in any geometry and orientation. It should be understood that the geometries shown in <FIG> are merely exemplary and that any geometries may be employed. <FIG> is a schematic drawing illustrating a perspective view of one embodiment of a reinforced sheet <NUM>. The reinforced sheet <NUM> has a length L in a longitudinal direction, and a width W in a lateral direction. The length L is greater than the width W. Thus, the sheet <NUM> may be referred to as an elongated sheet.

In one embodiment, the reinforced sheet <NUM> includes reinforcement cords <NUM> extending in a longitudinal direction, and which are embedded in a thermoplastic material <NUM>. The reinforcement cords <NUM> are constructed of a high strength material. Exemplary materials for reinforcement cords <NUM> include, without limitation, polyester, nylon, aramid, glass, steel, and other metal. In one specific embodiment, the thermoplastic material <NUM> is a thermoplastic elastomer resin. An exemplary thermoplastic elastomer resin is commercially sold under the brand name HYTREL by DUPONT. However, it should be understood that any thermoplastic elastomer resin may be employed. Thermoplastic elastomer resins exhibit desirable resilience, heat and chemical resistance, strength, and durability. However, other polymeric materials may be selected to embed the reinforcement cords if different properties are desired.

The reinforced cords <NUM> may be embedded in the thermoplastic material <NUM> through pultrusion, co-extrusion, or other means of cord coating. The resulting reinforced sheet <NUM> would be flexible due to thin gauge and low modulus.

<FIG> is a perspective view of the reinforced sheet <NUM> formed into a hoop. The reinforced sheet <NUM> is bent such that the reinforcement cords <NUM> extend in a circumferential direction. In an alternative embodiment (not shown), the reinforced sheet may be cut at an angle and the hoop formed such that the reinforcement cords extend at an acute angle with respect to the circumferential direction. After the hoop is formed, the ends of the reinforced sheet <NUM> are joined together. The ends may be joined with an adhesive, or by welding or brazing.

<FIG> is a perspective view of the reinforced sheet <NUM> disposed on a tire structure <NUM> for a non-pneumatic tire. The tire structure <NUM> has an inner ring <NUM> having an axis of rotation, a generally annular outer ring <NUM>, and support structure in the form of an interconnected web extending between the inner ring <NUM> and the outer ring <NUM>. The interconnected web is formed by a plurality of web elements <NUM> that define polygonal openings. In this particular embodiment, the web elements <NUM> form a plurality of hexagonal and substantially trapezoidal shapes. In one embodiment, the inner ring <NUM>, outer ring <NUM>, and support structure <NUM> are constructed of the same material. In alternative embodiments, different materials may be employed. The tire structure <NUM> is merely exemplary, and it should be understood that the reinforced sheet <NUM> may be disposed about any non-pneumatic tire structure, including structures having webbing and structures having spokes.

The reinforced sheet <NUM> is attached to the outer ring <NUM>. In the illustrated embodiment, the reinforced sheet <NUM> is first formed into a hoop in the manner described above. The width of the hoop is substantially the same as the width of the outer ring <NUM>. In one embodiment, the hoop is attached to the outer ring <NUM> by spin welding the hoop to the outer ring <NUM>. Spin welding is a friction welding technique used on thermoplastic materials, in which the parts to be welded are heated by friction. The heat may be generated by turning the hoop and holding the tire structure <NUM> stationary against the hoop, or by turning the tire structure <NUM> and holding the hoop stationary against the tire structure <NUM>. This is continued until the heat of friction between the parts reaches a sufficient level for the parts to weld. The stationary part is then released to spin as well, while pressure is applied along the axis of rotation, holding the parts together as they cool. Such a process may require the hoop to have a thickness that is greater than a predetermined minimum thickness. In alternative embodiments, the hoop is attached to the outer ring with an adhesive, by welding or brazing, or by a chemical bond, such as by heating the components to create a bond.

In an alternative embodiment, the reinforced sheet <NUM> is a ribbon having a width that is less than the width of the outer ring. In such an embodiment, the elongated sheet may have a greater initial width and the elongated sheet is cut into ribbons having a smaller width. Alternatively, the elongated sheet may be initially formed as a ribbon.

When the reinforced sheet <NUM> is formed as a ribbon, the step of attaching the reinforced sheet <NUM> to the outer ring <NUM> of the tire structure <NUM> includes spirally winding the ribbon about the outer ring <NUM> of the tire structure <NUM>. The ribbon may be affixed to the outer ring <NUM> with an adhesive, by welding or brazing, or by a chemical bond, such as by heating the components to create a bond.

After the reinforced sheet <NUM> is attached to the outer ring <NUM>, the reinforced sheet <NUM> may be described as being part of the outer ring <NUM>. In other words, the outer ring <NUM> may be described as including a lower layer constructed of a first material and an upper layer constructed of a second material different from the first material, wherein the second material has the circumferential reinforcements embedded therein.

After the reinforced sheet <NUM> is attached to the outer ring, a circumferential tread is disposed about the reinforced sheet <NUM>. Where the reinforced sheet <NUM> is described as being part of the outer ring <NUM>, the circumferential tread may be described as being disposed about the outer ring <NUM>. In one embodiment, the circumferential tread includes a tread reinforcement layer spaced from a bottom of the circumferential tread. Examples of circumferential treads disposed on reinforced sheets are shown in <FIG>.

<FIG> is a schematic drawing illustrating a partial cross-section of one embodiment of a non-pneumatic tire <NUM>. In this embodiment, the non-pneumatic tire <NUM> includes the tire structure <NUM> of <FIG>, including the inner ring <NUM>, the outer ring <NUM>, and the support structure <NUM>. It should be understood, however, that any tire structure may be employed.

A reinforced hoop <NUM> having the same width as the outer ring <NUM> is disposed about the outer ring <NUM> in one of the manners described above. The reinforced hoop is constructed of one of the materials described above and includes reinforcement cords <NUM>.

A circumferential tread includes a first elastomeric layer <NUM> disposed about the reinforced hoop <NUM>. The first elastomeric layer may be rubber or any other suitable elastomeric material. A tread reinforcement layer <NUM> having reinforcement cords <NUM> is disposed above the first elastomeric layer <NUM>. Exemplary materials for reinforcement cords <NUM> include, without limitation, polyester, nylon, aramid, glass, steel, and other metal. Where the reinforcement cords <NUM> are steel, the reinforcement layer <NUM> may be referred to as a steel belt. In the illustrated embodiment, the reinforcement layer <NUM> is a single layer of steel belts. In alternative embodiments, multiple layers of steel belts may be employed. The reinforcement cords <NUM> in the tread reinforcement layer <NUM> may be constructed of the same material as the reinforcement cords <NUM> in the reinforced hoop <NUM>, or they may be constructed of different materials. The reinforcement cords <NUM> in the tread reinforcement layer <NUM> may extend in a circumferential direction, or in a non-circumferential direction, such as at an acute angle with respect to the circumferential direction.

In the illustrated embodiment, the tread reinforcement layer <NUM> includes a skim material that embeds the reinforcement cords. The skim material may be the same as the first elastomeric layer <NUM>, or it may be a different material. For example, the skim material may be the same material as the reinforced hoop <NUM>.

The tread reinforcement layer <NUM> is spaced from the bottom surface of the circumferential tread (and thus spaced from the reinforced hoop <NUM>) by the thickness T of the first elastomeric layer <NUM>. In one embodiment, the first elastomeric layer <NUM> has a thickness T of at least <NUM> inches (<NUM>). In alternative embodiments the first elastomeric layer has a thickness between <NUM> inches (<NUM>) and <NUM> inches (<NUM>).

A second elastomeric layer <NUM> is disposed above the tread reinforcement layer <NUM>. In one embodiment, the second elastomeric layer <NUM> is constructed of the same material as the first elastomeric layer <NUM>. In an alternative embodiment, the first and second elastomeric layers <NUM>, <NUM> are constructed of different materials. The second elastomeric layer <NUM> has tread elements formed therein. Exemplary tread elements include, without limitation, grooves, sipes, ribs, blocks, lugs, and other recesses and projections. In an alternative embodiment (not shown), the second elastomeric layer does not include any tread elements.

In one embodiment, a circumferential tread with the first elastomeric layer <NUM>, the tread reinforcement layer <NUM> and the second elastomeric layer <NUM> is pre-formed. The circumferential tread is then attached to the reinforced hoop <NUM> with an adhesive, by welding or brazing, or by a chemical bond, such as by heating the components to create a bond.

In an alternative embodiment, the circumferential tread may be built layer by layer onto the reinforced hoop <NUM>. The building process would include placing the first elastomeric layer <NUM> about the reinforced hoop <NUM>, placing the tread reinforcement layer <NUM> about the first elastomeric layer <NUM>, and placing the second elastomeric layer <NUM> about the tread reinforcement layer <NUM>. In one embodiment, the layers are attached to each other at each step, such as with an adhesive, by welding or brazing, or by a chemical bond, such as by heating the components to create a bond. In an alternative embodiment, the tire is heated after all of the layers are assembled, such that the layers bond to each other.

The reinforced hoop <NUM>, first elastomeric layer <NUM>, and tread reinforcement layer <NUM> together form a shear element or shear structure having an elastic region disposed between upper and lower inelastic regions. The shear element may help the non-pneumatic tire <NUM> carry a greater load.

<FIG> is a schematic drawing illustrating a partial cross-section of an alternative embodiment of a non-pneumatic tire <NUM>. In this embodiment, the non-pneumatic tire <NUM> also includes the tire structure <NUM> of <FIG>, including the inner ring <NUM>, the outer ring <NUM>, and the support structure <NUM>. It should be understood, however, that any tire structure may be employed.

A circumferential tread <NUM> is disposed about the reinforced hoop <NUM>. The circumferential tread <NUM> includes a tread reinforcement layer defined by reinforcement cords <NUM> embedded therein. The reinforcement cords <NUM> may be the same as the reinforcement cords <NUM> described above with respect to <FIG>, including any alternative embodiments discussed above.

The reinforcement cords <NUM> are spaced from the bottom surface of the circumferential tread (and thus spaced from the reinforced hoop <NUM>) by the thickness T of the tread material below the reinforcement cords. This thickness may be the same as the thicknesses of the first elastomeric layer <NUM> described above.

The reinforced hoop <NUM>, the reinforcement cords <NUM>, and the tread material therebetween form a shear element or shear structure having an elastic region disposed between upper and lower inelastic regions. The shear element may help the non-pneumatic tire <NUM> carry a great load.

The shear element may be formed in other ways. For example, <FIG> is a schematic drawing illustrating an alternative embodiment of a shear element formed by a spiral-wrapped ribbon <NUM> having reinforcement cords <NUM>, a first elastomeric layer <NUM>, and a tread reinforcement layer <NUM> having reinforcement cords <NUM>. A second elastomeric layer <NUM> is disposed above the tread reinforcement layer <NUM>. The <FIG> embodiment is substantially the same as the <FIG> embodiment, with the exception of the spiral-wrapped ribbon. The alternative embodiments discussed with respect to <FIG> should thus be understood to also apply to <FIG>.

<FIG> is a schematic drawing illustrating another alternative embodiment of a shear element formed by a spiral-wrapped ribbon <NUM> having reinforcement cords <NUM> and a circumferential tread <NUM> having a tread reinforcement layer <NUM> embedded therein. The <FIG> embodiment is substantially the same as the <FIG> embodiment, with the exception of the spiral-wrapped ribbon. The alternative embodiments discussed with respect to <FIG> should thus be understood to also apply to <FIG>.

To the extent that the term "includes" or "including" is used in the specification or the claims, it is intended to be inclusive in a manner similar to the term "comprising" as that term is interpreted when employed as a transitional word in a claim. Furthermore, to the extent that the term "or" is employed (e.g., A or B) it is intended to mean "A or B or both. " When the applicants intend to indicate "only A or B but not both" then the term "only A or B but not both" will be employed. Thus, use of the term "or" herein is the inclusive, and not the exclusive use. See, Bryan A. Garner, A Dictionary of Modern Legal Usage <NUM> (2d. Also, to the extent that the terms "in" or "into" are used in the specification or the claims, it is intended to additionally mean "on" or "onto. " Furthermore, to the extent the term "connect" is used in the specification or claims, it is intended to mean not only "directly connected to," but also "indirectly connected to" such as connected through another component or components.

Claim 1:
A non-pneumatic tire (<NUM>; <NUM>; <NUM>; <NUM>; <NUM>) comprising:
an inner ring (<NUM>; <NUM>; <NUM>; <NUM>) having an axis of rotation;
an outer ring (<NUM>; <NUM>; <NUM>; <NUM>);
a reinforced sheet (<NUM>) attached to a radially outer surface of the outer ring (<NUM>),
wherein the reinforced sheet (<NUM>) has a length (L) in a longitudinal direction, which longitudinal direction corresponds to the circumferential direction of the non-pneumatic tire, and a width (W) in a lateral direction,
wherein the length (L) is greater than the width (W),
wherein the reinforced sheet (<NUM>) is a sheet of thermoplastic material (<NUM>) having a plurality of reinforcement cords (<NUM>) constructed of a high strength material embedded therein and extending in a tire circumferential direction,
wherein the outer ring (<NUM>; <NUM>; <NUM>; <NUM>) is constructed of a material different from the thermoplastic material (<NUM>);
a support structure (<NUM>; <NUM>; <NUM>; <NUM>) extending from the inner ring (<NUM>; <NUM>; <NUM>; <NUM>) to the outer ring (<NUM>; <NUM>; <NUM>; <NUM>), wherein the support structure (<NUM>) is in the form of an interconnected web extending between the inner ring (<NUM>) and the outer ring (<NUM>); and
a circumferential tread (<NUM>) extending about the outer ring (<NUM>; <NUM>; <NUM>; <NUM>), the circumferential tread (<NUM>) including a tread reinforcement layer (<NUM>; <NUM>; <NUM>; <NUM>) spaced from a bottom of the circumferential tread (<NUM>),
characterised in that
the interconnected web is formed by a plurality of web elements (<NUM>) that define a plurality of hexagonal and substantially trapezoidal shaped openings.