Patent Description:
A continuing goal of the tire industry is the improvement of the performance of tires. Desirable characteristics for tires may be light weight, low drag, good traction, minimal runout, low noise, good handling, low treadwear, and/or low rolling resistance. Further, the tire industry strives for tire constructions well-suited for specific conditions and uses. Optimization of handling using one construction, and high-speed durability using another construction, may be one method for addressing a specific condition. Light weight tires with improved and/or maintained physical properties and optimization for different conditions are desirable goals for tire designers.

<CIT> describes a tire in accordance with the preamble of claim <NUM>.

Further tires having wrap around strips at the edges of belt plies are known from <CIT>, <CIT> and <CIT>.

"Apex" means an elastomeric filler located radially above the bead core and between the plies and the turnup ply.

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

"Circumferential" means 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.

"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. The "cord angle" is measured in a cured but uninflated tire.

"Crown area" means that portion of the tire within the width limits of the tire tread.

"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.

"Ply" means a cord-reinforced layer of rubber-coated radially deployed or otherwise parallel cords.

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

"Tread width" means the arc length of the tread surface in a plane including the axis of rotation of the tire.

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

A tire in accordance with the present invention includes a carcass ply and a belt structure disposed radially outward of the carcass ply in a crown portion of the tire. The belt structure includes a first belt ply, a second belt ply radially adjacent the first belt ply, an overlay ply radially adjacent the first belt ply, a first wrap around strip encompassing both axial edges of the first belt ply, and a second wrap around strip encompassing both axial edges of the second belt ply.

The overlay ply has an axial width less than a maximum axial width of the first belt ply and a maximum axial width of the second belt ply.

According to another preferred aspect of the tire, the first wrap around strip includes reinforcing cords.

According to yet another preferred aspect of the tire, the second wrap around strip includes reinforcing cords.

According to still another preferred aspect of the tire, the first wrap around strip includes reinforcing fibers.

According to yet another preferred aspect of the tire, the second wrap around strip includes reinforcing fibers.

According to still another preferred aspect of the tire, the first wrap around strip includes reinforcing fabric.

According to yet another preferred aspect of the tire, the second wrap around strip includes reinforcing fabric.

According to still another preferred aspect of the tire, radially outer portions of the first wrap around strips axially overlap axially outer edges of the overlay ply.

According to yet another preferred aspect of the tire, radially inner portions of the first wrap around strips axially overlap radially outer portions of the second wrap around gum strips.

A method in accordance with the present invention reinforces a crown area of a tire. The method includes the steps of: extending a carcass ply from a first bead portion to a second bead portion; placing a belt structure radially outward of the carcass ply in the crown area of the tire, the belt structure including a first belt ply, a second belt ply, an overlay ply, a first wrap around strip, and a second wrap around strip; encompassing each axial edge of the first belt ply with a first wrap around strip; encompassing each axial edge of the second belt ply with a second wrap around strip; axially overlapping each axial edge of the overlay ply with a radially outer portion of the first wrap around strip; and axially overlapping a radially inner portion of a first wrap around strip with a radially outer portion of the second wrap around strip.

The overlay ply has an axial width less than both a maximum axial width of the first belt ply and a maximum axial width of the second belt ply.

According to a preferred aspect of the method, radially outer portions of the first wrap around strips directly contact axially outer edges of the overlay ply.

According to yet another preferred aspect of the method, radially inner portions of the first wrap around strips directly contact radially outer portions of the second wrap around gum strips.

<FIG> is a cross-sectional view of an example tire <NUM>, for mounting on a tire rim <NUM>, designed to be capable of continued operation during inflated, under-inflated, and deflated conditions. One half of the cross-sectional view of the example tire <NUM> is shown, it being understood that, the other half may be a mirror image of that which is illustrated in <FIG>. The example tire <NUM> has at least one carcass reinforcing ply <NUM> extending from one bead area <NUM> of the tire to an opposing bead area (not shown). The ends of the reinforcing ply <NUM> are preferably turned axially inward to axially outward about bead cores <NUM> and bead apexes <NUM>. The terminal ends of the reinforcing ply <NUM> preferably extend past the radially outer ends of the bead apexes <NUM> thereby enveloping the bead apexes.

Preferably, there is a sidewall insert <NUM> located in each sidewall region of the example tire <NUM>.

The insert <NUM> is preferably located adjacent to the tire innerliner <NUM> or axially outward of the reinforcing ply <NUM>. The insert <NUM> is preferably formed of elastomeric material and preferably extends from the crown area, such as from radially inward of a belt structure to radially inward of the outermost terminal end of the bead apexes <NUM> that overlap the bead apexes <NUM>. The elastomeric material of the insert <NUM> is preferably selected to provide the example tire <NUM> with support during underinflated and deflated operation of the tire.

In the crown area of the example tire <NUM>, a belt structure is located radially outward of the carcass ply <NUM>. The belt structure has at least two inclined, crossed cord belt plies <NUM>, <NUM> and a radially outer overlay ply <NUM>. The cords are preferably inclined with respect to the circumferential direction of the example tire <NUM> in the first belt ply <NUM> and the cords in the second belt ply <NUM> directly adjacent the first belt ply <NUM> are preferably inclined at similar, but opposing, angles to the cords in the first belt ply <NUM>. These angles are preferably both in a range of from <NUM> to <NUM> degrees.

Radially outward of the crossed cord belt plies <NUM>, <NUM> is the overlay ply <NUM>. The overlay ply <NUM> may have a lateral width in a range of from <NUM> to <NUM> percent of the maximum lateral width of the crossed cord plies <NUM>, <NUM>.

Preferably, the radially inner second belt ply <NUM> is the laterally widest ply. The lateral width of the adjacent first belt ply <NUM> is preferably in a range of from <NUM> to <NUM> percent of the lateral width of the second belt ply. The lateral width of the adjacent overlay ply is preferably in a range of from <NUM> to <NUM> percent of the lateral width of the first belt ply <NUM>.

The overlay ply <NUM> is preferably reinforced with cords inclined at angles between of <NUM>° and -<NUM>°, more preferably at angles between <NUM>° and -<NUM>° or at angles between -<NUM>° to <NUM>°, with respect to the circumferential direction of the example tire <NUM>.

As shown, the overlay ply <NUM> has a width less than a maximum width of the crossed cord plies of the belt structure <NUM>, <NUM> (<FIG>).

Only one or preferably both lateral edges <NUM> of the first belt ply <NUM> are encompassed by first wrap around gum strips <NUM> (one shown).

Preferably, each first gum strip <NUM> extends on the radially upper side of the first belt ply <NUM> over a lateral distance of preferably <NUM> to <NUM> percent, more preferably <NUM> to <NUM> percent, of the lateral width of the first belt ply <NUM>.

Preferably and as shown in <FIG>, each first gum strip <NUM> extends on the radially outer side of the first belt ply <NUM> over a lateral distance that is lower, preferably <NUM> to <NUM> percent lower, than the respective distance on the radially inner side of the first belt ply <NUM>.

Preferably and as shown in <FIG>, each first gum strip <NUM> extends on the radially outer side partially under the overlay ply <NUM>.

The overlay ply <NUM> is in contact with each first gum strip <NUM> over a lateral distance in a range of from <NUM> to <NUM> percent or from <NUM> to <NUM> percent of the lateral width of the overlay belt ply <NUM>.

Only one or preferably both lateral edges <NUM> of the second belt ply <NUM> are encompassed by second wrap around gum strips <NUM> (one shown).

Preferably and as shown in <FIG>, each second gum strip <NUM> extends on the radially upper side of the second belt ply <NUM> over a lateral distance of preferably <NUM> to <NUM> percent, more preferably <NUM> to <NUM> percent, of the lateral width of the second belt ply <NUM>.

Preferably and as shown in <FIG>, each second gum strip <NUM> extends on the radially outer side of the second belt ply <NUM> over a lateral distance that is higher, preferably <NUM> to <NUM> percent higher, than the respective distance on the radially inner side of the second belt ply <NUM>.

Preferably, the radially inner side of the first gum strip <NUM> and the radially outer side of the second gum strip <NUM> are adjacent to each other and partially overlap.

Preferably and as shown in <FIG>, each second gum strip <NUM> extends on the radially upper side of the second belt ply <NUM> laterally under the first gum strip <NUM> over a lateral distance in a range of from <NUM> to <NUM> percent of the lateral width of the first belt ply <NUM>.

The first and second wrap around gum strips <NUM>, <NUM> may or may not include reinforcement structures such as cords, fibers, short fibers, fabric, etc..

Preferably, the construction of the tire <NUM> is symmetrical with respect to the equatorial plane of the tire <NUM>.

The disclosed belt/overlay construction <NUM>, <NUM>, <NUM>, <NUM>, <NUM> allows it to mitigate material flow in the area or the belt edges <NUM>, <NUM> and to thereby prevent cords of the second belt ply <NUM> from directly contacting cords of the first belt ply <NUM> and cords of the first belt ply <NUM> from directly contacting cords of the overlay ply <NUM> there, thereby increasing durability of the crown area of the tire <NUM>. This is of particular relevance when the tire <NUM> is a truck tire or when it is a self-supporting tire (run-flat tire).

Claim 1:
A tire comprising a carcass ply (<NUM>) and a belt structure disposed radially outward of the carcass ply (<NUM>) in a crown portion of the tire (<NUM>), the belt structure including a first belt ply (<NUM>), a second belt ply (<NUM>) radially adjacent the first belt ply (<NUM>), an overlay ply (<NUM>) radially adjacent the first belt ply (<NUM>), wherein a first wrap around strip (<NUM>) encompasses one or both axial edges (<NUM>) of the first belt ply (<NUM>), and a second wrap around strip (<NUM>) encompasses one or both axial edges of the second belt ply (<NUM>), and wherein the overlay ply (<NUM>) has an axial width less than a maximum axial width of the first belt ply (<NUM>) and a maximum axial width of the second belt ply (<NUM>), characterized in that the overlay ply (<NUM>) is in contact with each first wrap around strip (<NUM>) over a lateral distance in a range of from <NUM> to <NUM> percent of the lateral width of the overlay belt ply (<NUM>).