Patent Description:
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, performance of these tires is limited. It is an object of the present invention to overcome this limitation and increase the load carrying capacity and durability of these spokes and hence the performance of the top loader non-pneumatic tire.

<CIT> describes a system and method of manufacturing a non-pneumatic support structure. The system comprises a core having a cylindrical hub and radially protruding extensions, a plurality of internal arcuate members for positioning a reinforcing layer about the core, a first side plate for securing the internal arcuate members in place relative to the core, and a second side plate for securing the core and the internal arcuate members to each other.

<CIT> describes a reinforced non-pneumatic tire and a system for molding such a tire. <CIT> discloses a non-pneumatic tire with spokes.

"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.

"Radial" and "radially" mean directions radially toward or away from the axis of rotation of the tire.

"Wheel" or "hub" means a structure for supporting the tire and mounting to the vehicle axle.

A system in accordance with a preferred aspect of the present invention cures and manufactures a partially cured tire assembly. The system includes an annular hub member slid into a corresponding annular, radially inner surface of the partially-cured tire assembly, a plurality of elongate spacer members for maintaining corresponding uniform cavity dimensions in the partially-cured tire assembly tire assembly by fastening the spacer members to the hub member with flap members of the partially-cured tire assembly tire assembly thereby enclosing a radially outermost surface of each of the spacer members, a first annular curing platen for axially securing the hub member and spacer members relative to each other, a second annular curing platen for axially securing the hub member and spacer members relative to each other; and a plurality of elongate inserts for creating a smooth, uniform outer cylindrical surface formed by a radially outer surface of each insert and flap members of the tire assembly positioned by the radially outermost surfaces of the spacer members.

According to a preferred aspect of the system, a plurality of mold members is placed circumferentially around a radially outer surface of a tread member.

According to a preferred aspect of the system, radially inner surfaces of the mold members together form a tread shaped outer surface in the radially outer surface of the tread member.

According to a preferred aspect of the system, the spacer members, first and second curing platens, triangular inserts, and mold members are heated in order to cure form the flap members, a shear band, and a tread member into a molded integral part of a complete, cured tire assembly.

According to a preferred aspect of the system, the elongate inserts have a triangular cross-section.

According to a preferred aspect of the system, the mold members are radially removable from around the complete, cured tire assembly.

According to a preferred aspect of the system, the curing platens are axially removable from the hub member, the elongate spacer members, and elongate inserts.

According to a preferred aspect of the system, the curing platens are heated by a hot liquid.

According to a preferred aspect of the system, the elongate spacer members platens are heated by steam.

According to a preferred aspect of the system, the elongate inserts are heated by electricity.

A method in accordance with a preferred aspect of the present invention completes the curing of a partially cured tire assembly. The method includes the steps of: sliding an annular hub member into a corresponding annular, radially inner surface of the partially-cured tire assembly; maintaining a plurality of spacer members within corresponding uniform cavities in the partially-cured tire assembly; fastening the spacer members to the hub member with uncured flap members of the partially-cured tire assembly enclosing a radially outermost surface of each of the spacer members; axially securing first and second curing platens, the hub member, and spacer members relative to each other; and creating a smooth, uniform outer cylindrical surface formed by a radially outer surface of each spacer member and each of the uncured flap members of the partially-cured tire assembly positioned by the radially outermost surfaces of the spacer members.

According to a preferred aspect of the method, a further step includes serially placing an uncured inner annular shear band and an uncured outer annular tread member of the partially cured tire assembly circumferentially around the uniform outer cylindrical surface.

According to a preferred aspect of the method, a further step includes affixing the uncured inner annular shear band and the uncured outer annular tread member of the partially cured tire assembly to each other.

According to a preferred aspect of the method, a further step includes placing a plurality of mold members circumferentially around a radially outer surface of the tread member.

According to a preferred aspect of the method, a further step includes forming a tread shaped outer surface in the outer surface of the tread member by radially inner surfaces of the mold members.

According to a preferred aspect of the method, a further step includes heating the spacer members, curing platens, elongate inserts, and mold members in order to form the flap members, shear band, and tread member into a fully cured tire assembly.

According to a preferred aspect of the method, a further step includes radially removing the mold members from around the fully cured tire assembly.

According to a preferred aspect of the method, a further step includes axially removing the curing platens from the hub member.

According to a preferred aspect of the method, a further step includes axially withdrawing the spacer members and inserts from the fully cured tire assembly to reveal stable cavities within a spoke structure of a rim-mountable, fully cured tire assembly.

According to a preferred aspect of the method, the heating step includes a medium from the group consisting of a hot liquid, steam, and electricity.

The present invention will be more clearly understood by the following description of some examples thereof, with reference to the accompanying drawings, in which:.

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.

As shown in <FIG>, an example tire assembly, such as that described in <CIT>, 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 <NUM>, nylon <NUM>,<NUM>, rayon, steel, glass fibers, carbon fiber, aramid, and/or a hybrid construction of these materials. The cords may be from <NUM> denier to <NUM> denier. The polymeric film may be from <NUM> to <NUM> thick. The spokes may be oriented at angle between <NUM> degrees and <NUM> 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 <NUM> and <NUM> for large scale tire assemblies. The inner central rim may include steel, cast iron, aluminum, aluminum alloys, magnesium allows, and/or iron alloys.

<FIG> show a system <NUM> in accordance with the present invention for curing and manufacturing partially cured pneumatic and/or non-pneumatic tire assemblies <NUM>. The system <NUM> includes an annular hub member <NUM> slid into a corresponding annular, radially inner surface <NUM> of the tire assembly <NUM>, a plurality of spacer members <NUM> for maintaining corresponding uniform cavity dimensions in the tire assembly <NUM> by fastening the spacer members <NUM> to the hub member <NUM> with flap members <NUM> of the tire assembly <NUM> enclosing a radially outermost surface <NUM> of each of the spacer members <NUM>, first and second curing platens <NUM>, <NUM> for axially securing the hub member <NUM> and spacer members <NUM> relative to each other, and a plurality of preferably triangular inserts <NUM> for creating a smooth, uniform outer cylindrical surface formed by a radially outer surface <NUM> of each triangular insert <NUM> and each of the flap members <NUM> of the tire assembly <NUM> positioned by the radially outermost surfaces <NUM> of the spacer members <NUM>. The curing platens <NUM>, <NUM> may also have spring hook members <NUM> for maintaining alignment with the spacer members <NUM> and the remaining parts of the assembly <NUM>.

An inner annular shear band <NUM> and an outer annular tread member <NUM> of the tire assembly <NUM> may be serially placed circumferentially around the uniform outer cylindrical surface <NUM>, <NUM> and affixed at least temporarily thereto and to each other <NUM>, <NUM>. This may be accomplished by building up layers <NUM>, <NUM> around the assembly <NUM> similar to a conventional tire building method (not shown) or by forming a complete annular band structure from the shear band <NUM> and the tread member <NUM> (<FIG>). A plurality of mold members <NUM> (six shown in <FIG>) may be placed circumferentially around a radially outer surface <NUM> of the tread member <NUM>. The mold members <NUM> have radially inner surfaces <NUM> for together forming a tread shaped outer surface in the outer surface <NUM> of the tread member <NUM>.

The spacer members <NUM>, curing platens <NUM>, <NUM>, triangular inserts <NUM>, and mold members <NUM> may be heated in order to cure form the flap members <NUM>, shear band <NUM>, and tread member <NUM> (e.g., uncured parts of the tire assembly <NUM>) into a molded integral part of a complete, cured tire assembly <NUM> having an appropriate tread <NUM> (<FIG>). Once curing is complete, the mold members <NUM> are radially removed from around the complete tire assembly <NUM>, the curing platens <NUM>, <NUM> are axially removed from the hub member <NUM>, and the spacer members <NUM> and inserts <NUM> are axially withdrawn from the tire assembly <NUM> to reveal stable cavities <NUM> within a spoke structure <NUM> of the mount-ready tire assembly <NUM>.

As shown in the <FIG>, a method <NUM>, in accordance with the present invention, cures and manufactures a partially cured tire assembly <NUM> into a completed, "ready-to-install", completely cured tire assembly <NUM>. The method <NUM> includes: a first step <NUM> of sliding an annular hub member <NUM> into a corresponding annular, radially inner surface <NUM> of the partially-cured tire assembly <NUM>; a second step <NUM> of maintaining a plurality of spacer members <NUM> within corresponding uniform cavity dimensions in the partially-cured tire assembly <NUM>; a third step <NUM> of fastening the spacer members <NUM> to the hub member <NUM> with flap members <NUM> of the partially-cured tire assembly <NUM> enclosing a radially outermost surface <NUM> of each of the spacer members <NUM>; a fourth step <NUM> of axially securing first and second curing platens <NUM>, <NUM>, the hub member <NUM>, and spacer members <NUM> relative to each other; a fifth step <NUM> of utilizing a plurality of triangular inserts <NUM> for creating a smooth, uniform outer cylindrical surface formed by a radially outer surface <NUM> of each spacer member <NUM> and each of the flap members <NUM> of the partially-cured tire assembly <NUM> positioned by the radially outermost surfaces <NUM> of the spacer members <NUM>; a sixth step <NUM> of serially placing an uncured inner annular shear band <NUM> and an uncured outer annular tread member <NUM> of the partially-cured tire assembly <NUM> circumferentially around the uniform outer cylindrical surface <NUM>, <NUM>; a seventh step <NUM> of affixing at least temporarily the uncured inner annular shear band <NUM> and the uncured outer annular tread member <NUM> of the partially-cured tire assembly <NUM> to each other <NUM>, <NUM>; an eighth step <NUM> of placing a plurality of mold members <NUM> circumferentially around a radially outer surface <NUM> of the tread member <NUM>; and a ninth step <NUM> of forming a tread shaped outer surface in the outer surface <NUM> of the tread member <NUM> by radially inner surfaces <NUM> of the mold members.

Claim 1:
A system for curing and manufacturing a partially cured tire assembly (<NUM>), the system (<NUM>) comprising:
an annular hub member (<NUM>) slid into a corresponding annular, radially inner surface (<NUM>) of the partially cured tire assembly (<NUM>);
a plurality of elongate spacer members (<NUM>) for maintaining corresponding uniform cavity dimensions in the partially cured tire assembly tire assembly (<NUM>) by fastening the spacer members (<NUM>) to the hub member (<NUM>) with flap members (<NUM>) of the partially cured tire assembly (<NUM>) thereby enclosing a radially outermost surface (<NUM>) of each of the spacer members (<NUM>);
a first annular curing platen (<NUM>) for axially securing the hub member (<NUM>) and spacer members (<NUM>) relative to each other;
a second annular curing platen (<NUM>) for axially securing the hub member (<NUM>) and spacer members (<NUM>) relative to each other; and
a plurality of elongate inserts (<NUM>) for creating a smooth, uniform outer cylindrical surface formed by a radially outer surface (<NUM>) of each insert (<NUM>) and flap members (<NUM>) of the partially cured tire assembly (<NUM>) positioned by the radially outermost surfaces (<NUM>) of the spacer members (<NUM>).