Patent Description:
Fabric belt assemblies and other fabric structures for tires are known. In one conventional assembly, a folded ply may be reinforced with cords of high modulus material and may have an overall width at least equal to that of the tread portion. Each of its lateral sides may be folded back, in a radially outward direction, around two unfolded single cut plies. The reinforcing cords of the folded ply may form an angle between <NUM> and <NUM> degrees relative to the with respect to the equatorial plane of the tire with those of the two single cut plies forming equal and opposed angles with respect to the equatorial plane of the tire.

Because of material limitations, conventional tire constructions have tended to be robust (e.g., heavy and many components, etc.). Such constructions may tend to have a high rolling resistance, which lowers fuel economy; and the bulk of the construction may have a tendency to limit handling response, as well as increasing material cost. It has been a continuing goal to identify lightweight and high strength materials, and to find suitable uses for such materials in tires, such that the weight of tires may be reduced while other properties are maintained.

Conventional aramid reinforcement material has shown fatigue resistance. This property made the material suitable for application of a relatively low twist to the cord, which made it possible to maintain durability and elongation characteristics in a lower density material. One conventional belt assembly has shown improved handling properties when reinforcement cords were reduced to <NUM> dTex from <NUM> dTex. One conventional overlay structure may be reinforced with aramid cords having a twist level between <NUM> TPI and <NUM> TPI (TPI = turn per <NUM>).

One conventional belt structure may be reinforced with <NUM> to <NUM> dTex aramid cords, with a measured toughness of <NUM> MPa to <NUM> MPa, an initial modulus <NUM>,<NUM> MPa to <NUM>,<NUM> MPa, a tenacity of <NUM> cN/Tex to <NUM> cN/Tex, and a dynamic flex fatigue retained break strength of <NUM>% to <NUM>%. These belts may be reinforced with reinforcement cords extending parallel to one another and making an angle of <NUM>° to <NUM>° with respect to the equatorial plane (EP) of the tire. The belt assembly may comprise a folded belt with folded portions on each lateral side folded radially over a cut belt. The axially outer portions of the folded belt may be folded in a radially outward direction and disposed radially outward of the cut belt.

Another conventional tire may have an overlay structure disposed radially outward from the belt assembly. Helical convolutions of a ribbon may be wound axially across two single cut plies such that the convolutions are in abutting contact with each other. The ribbon may be reinforced with cords of textile material.

<CIT> discloses finishing strips for tires, which have a fabric material. The fabric comprises interwoven warp and weft elements. The warp elements comprise a plurality of filaments of natural or synthetic textile substances. The weft elements are single or monofilaments which can have any suitable cross section, e.g., round, flat, rectangular, or other cross-sections.

<CIT> discloses high tenacity, oblong cross-section monofilaments.

<CIT> discloses reinforcing elements for tires, comprising a plurality of elongated metallic members with substantially rectangular cross-section. A single wrap member is helically disposed around the elongated metallic members such that each turn of the wrap filament member is spaced apart from the next adjacent turns of the wrap.

The invention relates to a fabric layer in accordance with claim <NUM> and to a tire in accordance with claim <NUM>.

According to a preferred aspect of the tire, a lateral stiffness of the fabric layer prevents lateral bending of the monofilament.

According to a preferred aspect of the tire, a lateral stiffness of the fabric layer prevents the monofilament from being moved by an external penetrating sharp object.

According to a preferred aspect of the fabric layer, the warp cord comprises nylon.

According to a preferred aspect of the fabric layer, the warp cord comprises nylon and aramid.

According to a preferred aspect of the fabric layer, a lateral stiffness of the fabric layer prevents lateral bending of the monofilament.

According to a preferred aspect of the fabric layer, a lateral stiffness of the fabric layer prevents the monofilament from being moved laterally by an external penetrating sharp object.

According to a preferred aspect of the fabric layer, the fabric layer maintains the warp cord at a constant lateral position.

According to a preferred aspect of the fabric layer, the weft cords maintain the warp cord at a constant lateral position.

A tire in accordance with a preferred aspect of the present invention includes a fabric layer with a plurality of warp cords each comprising a monofilament and a multifilament wrapped around the monofilament; and a plurality of weft cords extending transversely over and under the warp cords, the monofilaments being nylon, the multifilaments being glass, the wefts cords being aramid.

According to a preferred aspect of the tire, the weft cords maintain the warp cords at constant lateral relative positions.

"Aramid" and "Aromatic polyamide" both mean a manufactured fiber in which the fiber-forming substance is generally recognized as a long chain of synthetic aromatic polyamide in which at least <NUM>% of the amide linkages are attached directly to the two aromatic rings. Representative of an aramid or aromatic polyamide is a poly (p-phenyleneterephthalamide).

"Aspect ratio" means the ratio of a tire section height to its section width. For example, the aspect ratio may be the maximum axial distance between the exterior of the tire sidewalls when unloaded and inflated at normal pressure, multiplied by <NUM>% for expression as a percentage. Low aspect ratio may mean a tire having an aspect ratio of <NUM> and below.

"Axial" and "axially" refer to lines or directions that are parallel to the axis of rotation of the tire.

"Cord" means one of the reinforcement strands which the reinforcement structures of the tire comprise.

"Cord angle" means the acute angle, left or right in a plan view of the tire, formed by a cord with respect to the equatorial plane (EP). The "cord angle" is measured in a cured but uninflated tire.

"Cord twist" means each yarn of the cord has its component filaments twisted together a given number of turns per unit of length of the yarn (usually expressed in turns per inch (TPI) or turns per meter (TPM)) and additionally the yarns are twisted together a given number of turns per unit of length of the cord. The direction of twist refers to the direction of slope of the spirals of a yarn or cord when it is held vertically. If the slope of the spirals conforms in direction to the slope of the letter "S", then the twist is called "S" or "left hand". If the slope of the spirals conforms in direction to the slope of the letter "Z", then the twist is called "Z" or "right hand". An "S" or "left hand" twist direction is understood to be an opposite direction from a "Z" or "right hand" twist. "Yarn twist" is understood to mean the twist imparted to a yarn before the yarn is incorporated into a cord, and "cord twist" is understood to mean the twist imparted to two or more yarns when they are twisted together with one another to form a cord. "dtex" is understood to mean the weight in grams of <NUM>,<NUM> meters of a yarn before the yarn has a twist imparted thereto.

"Cut belt ply" refers to a belt having a width less than the tread width, which lies flat over the carcass plies in the crown area of the tire.

"Denier" means the weight in grams per <NUM> meters (unit for expressing linear density).

"Dtex" means the weight in grams per <NUM>,<NUM> meters.

"Equatorial plane (EP)" means the plane perpendicular to the tire's axis of rotation and passing through the center of its tread; or the plane containing the circumferential centerline of the tread.

"Fabric" means a network of essentially unidirectionally extending cords, which may be twisted, and which in turn are composed of a plurality of a multiplicity of filaments (which may also be twisted) of a high modulus material.

"Fiber" is a unit of matter, either natural or man-made, that forms the basic element of filaments; characterized by having a length at least <NUM> times its diameter or width.

"Filament count" means the number of filaments that make up a yarn. Example: <NUM> denier polyester has approximately <NUM> filaments.

"Multifilament" means a bundle of individual filaments (usually hundreds of filaments in a bundle) forming a flexible cord structure.

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

"Warp" means, in weaving/forming of fabric, lengthwise or longitudinal warp yarns, filaments, threads, cables, fibers, and/or cords may be held stationary in tension on a frame or loom while transverse "weft" yarns, filaments, threads, cables, fibers, and/or cords may be drawn through, and inserted over-and-under, the warp yarns, filaments, threads, fibers, and/or cords.

"Weft" means, in weaving/forming of fabric, transverse yarns, filaments, threads, cables, fibers, and/or cords may be drawn through, and inserted over-and-under, "warp" yarns, filaments, threads, cables, fibers, and/or cords. A single weft yarn, filament, thread, cable, fiber, and/or cord of a weft crossing the "warp" yarns, filaments, threads, cables, and/or cords may be termed a "pick". Conventional weft yarns, filaments, threads, cables, fibers, and/or cords may only function to maintain the lateral spacing of the "warp" yarns, filaments, threads, cables, fibers, and/or cords during assembly and pre-installation handling.

"Yarn" is a generic term for a continuous strand of textile fibers or filaments. Yarn occurs in the following forms: (<NUM>) a number of fibers twisted together; (<NUM>) a number of filaments laid together without twist; (<NUM>) a number of filaments laid together with a degree of twist; (<NUM>) a single filament with or without twist (monofilament); and (<NUM>) a narrow strip of material with or without twist.

With reference to <FIG>, there is represented an example tire <NUM>, pneumatic or non-pneumatic, for use with the present invention. The tire <NUM> preferably has a pair of substantially inextensible bead cores <NUM>, <NUM> axially spaced apart with two carcass plies <NUM>, <NUM> extending between the bead cores. The carcass plies may be folded axially and radially outward about each of the bead cores <NUM>, <NUM> and be reinforced by cords substantially parallel to each other in the same ply at an angle of <NUM>° to <NUM>° with respect to the equatorial plane (EP) of the tire <NUM>. Cords belonging to adjacent carcass plies <NUM>, <NUM> may generally have opposite angles crossing each other at an angle of <NUM> degrees to <NUM> degrees. The cords of the carcass plies <NUM>, <NUM> may be any suitable material, such as steel, nylon, rayon, aramid, and/or polyester. The tire <NUM> may have carcass plies <NUM>,<NUM> of side-by-side polyester or rayon cables and a crown area <NUM> reinforced by a belt assembly <NUM> located radially inward of the tire tread <NUM>. The tire <NUM> may have an aspect ratio between <NUM> and <NUM>.

The tire <NUM> may further include a belt structure <NUM> with an essentially rigid folded belt <NUM> and a cut belt <NUM> disposed radially outward of the folded belt. Both belts <NUM>, <NUM> may be reinforced with, for example, aramid cables or yarns. The belts <NUM>, <NUM> may have identical or different constructions. Such cords may be treated (coated) with one or more layers of adhesive in a process known as dipping. The modulus of a treated cord may be a function of the twist of the different yarns used in the cord, the cord twist, and the manner that the cord is subjected to the dipping operation.

Cords of the folded belt <NUM> may be substantially parallel to each other and make an angle of <NUM>° to <NUM>° with respect to the equatorial plane (EP) of the tire <NUM>. The axially outer portions of the folded belt <NUM> may be folded back on both lateral sides in a radially outward direction over axial edges of the cut belt <NUM> with the folded portions <NUM>, <NUM> being symmetrical with respect to the equatorial plane (EP). The folded portions <NUM>, <NUM> may each have a transverse width between <NUM>% and <NUM>%, or <NUM>% and <NUM>% of the tread width (TW).

As shown in <FIG>, another example tire 10a, for use with the present invention, includes one carcass ply 13a wrapped around beads 11a, 12a. The belt structure <NUM> preferably includes belts <NUM>, <NUM> reinforced with aramid cords and overlays <NUM>, <NUM> disposed radially outward of the belts <NUM>, <NUM>. The belts <NUM>, <NUM> may have identical or different constructions. The overlays <NUM>, <NUM> may be single sheets of overlay material, a cut overlay (e.g., reinforcement cords in the overlay discontinuous at random locations throughout the tire), and/or a spiral overlay. The reinforcing cords in the overlay <NUM>, <NUM> may comprise nylon, polyester, polyamine, aramid, and/or any other suitable overlay reinforcement material.

Generally, it may be advantageous to provide improved cut and puncture resistance to tires, such as the tires <NUM>, 10a described above, without degrading other functional characteristics of the tires. Further, an increased cut and puncture resistant protective cord, which may be applied on tires during retreading, would also be desirable (e.g., easily skived in retread surface preparations, etc.).

Additionally, a flat/obround shape monofilament may be used to resist the monofilament from being pushed out/sideways by a penetrating object. All else being equal, a monofilament having a round/circular cross-section may have less lateral bending stiffness than an obround/flat cross-section monofilament at an equivalent cross-sectional area. Therefore, the flat/obround monofilament cord may resist against being pushed sideways by a penetrating object more than a round/circular cross-section monofilament cord. The increased width may thereby assist the flat/obround monofilament in stopping penetrating objects more than a round cross-section monofilament.

To increase the strength of this flat monofilament construction, in accordance with the present invention, each monofilament is wrapped with another cord, such as, for example, an aramid multifilament cord and/or a glass multifilament cord. The wrapping may be achieved by hybrid cord twisting.

As shown in <FIG>, one construction <NUM> has a single flat monofilament <NUM> wrapped with one multifilament cord <NUM>. The monofilament <NUM> is preferably nylon and/or other suitable material. The multifilament(s) are preferably aramid, glass, carbon, and/or other suitable material. Preferably, the flat monofilament has in cross-section a ratio of width (lateral width) to height or thickness (radial height) in a range of from <NUM> to <NUM>, more preferably from <NUM> to <NUM>.

As shown in <FIG>, another construction <NUM> has a plurality of single flat monofilaments <NUM> wrapped with one multifilament cord <NUM>. The monofilaments <NUM> are preferably nylon and/or other suitable material. The multifilament(s) are preferably aramid, glass, carbon, and/or other suitable material. Preferably, the flat monofilament has in cross-section a ratio of width (lateral width) to height or thickness (radial height) in a range of from <NUM> to <NUM>, more preferably from <NUM> to <NUM>.

As shown in <FIG>, this plural construction <NUM>/<NUM> is combined with a skeleton of weft cords <NUM> to create a woven fabric <NUM> further enhancing cut and puncture resistance. The monofilaments <NUM> are preferably nylon and/or other suitable material. The multifilament(s) <NUM> is preferably aramid, glass, carbon, and/or other suitable material. The wefts cords <NUM> are preferably aramid, glass, carbon, and/or other suitable material.

Claim 1:
A fabric layer (<NUM>) for use in a tire (<NUM>), the fabric layer including a single flat monofilament (<NUM>) wrapped with one or more multifilament cords (<NUM>),
wherein the single flat monofilament (<NUM>) wrapped with one or more multifilament cords (<NUM>) is used as a warp cord, and wherein the fabric layer further comprises a plurality of weft cords (<NUM>) extending transversely over and under the warp cords.