Industrie Pirelli S.p.a.

Pirelli Coordinamento Pneumatici S.p.a.

Luigi Maiocchi

Giuliano Ghilardi

Giuseppe Tavazza

Luigi Silva

Carlo Franchini

The metal core used for reinforcing tire beads is constituted by a plurality of coils of wire (16), (17), (18), axially arranged side-by-side and radially superimposed, in which the wire has a cross section of modular shape with two equal and parallel opposite sides (1), (2), the profiles (15) of the corresponding ends of the opposite sides having a distance, from the axis of said pair of sides, whose value varies from one side to the other, said variation comprising at least one symmetrical deviation along, the development of its cross sectional profile.

Beads of pneumatic tires for vehicle wheels

The metal core used for reinforcing tire beads is constituted by a plurality of coils of wire (16), (17), (18), axially arranged side-by-side and radially superimposed, in which the wire has a cross-section of modular shape with two equal and parallel opposite sides (1), (2), the profiles (15) of the corresponding ends of the opposite sides having a distance, from the axis of said pair of sides, whose value varies from one side to the other, said variation comprising at least one symmetrical deviation along the development of its cross-sectional profile.

A tire with a radial carcass having a breaker structure that comprises two radially overlapped layers of metallic fabric reinforced by cords transversely disposed with respect to the circumferential direction of the tire. These cords are crossed over each other and, on each axial extremity of the two layers, there is positioned at least a rubberized fabric strip reinforced by metallic cords of high elongation (HE) or very high elongation (VHE) in combination with Hybrid textile cords (Aramide/Polyamide) disposed in the circumferential direction and having, in the vulcanized tire, a modulus of elongation of non-increasing value passing from the axially outermost cord to the axially innermost one. This strip is suitably constructed by the coupling of cords of (axially from the outside to the inside) HE-VHE (High Elongation--Very High Elongation), HE-Hybrid (High Elongation--Aramide/Polyamide) and VHE-Hybrid.

Reinforcing armouring of tires for vehicle wheels

Tire

An annular reinforcing structure for vehicle tires of a radial carcass has at least two radially superimposed layers of metal cords having an elongation at break between 2.6% and 3.2%. Two reinforcing rings are disposed in a radially external position at the extremities of the layers of metal cords with the axially outer edges coinciding with each other. The rings have a width between 7% and 40% of the width of the radially inner layers, and comprise metal cords having an elongation at break between 4% and 8%. The metal cords are oriented according to the longitudinal direction of the tire and are disposed in at least two radially superimposed strips.

Annular reinforcing structure of radial tires

A pneumatic tire having a radial carcass which is adapted for use on heavy duty motor vehicles such as trucks and buses is provided with an annular reinforcing structure in the crown of the tire between the carcass and the tread band having at least three layers of metal cords with the two layers which are radially inner of the third layer being of cords having an ultimate elongation of about 3% and the cords of the third layer having an ultimate elongation of about 4% to about 8%. The cords of each of the two radially inner layers are substantially parallel to each other and inclined with respect to the direction of travel of the tire but the cords of one of the two layers cross those of the other layer. The cords of the third layer are substantially parallel to each other and to the direction of travel of the tire. The third layer has a central strip astride the center line of the tire and a lateral strip on each side of the center strip which is more resistant to tension and compression stresses than the center strip.

Breaker for radial tire

A pneumatic tire for a motor vehicle has a removable tread fastened to the casing by annular projections on one locked in annular grooves in the other when the tire is inflated. The tread is supported by a breaker structure underlying the tread in the crown portion of the casing. The breaker has an annular strip of metallic fabric and an annular tape of metallic fabric on each side of the strip and between the annular strip and underlying carcass. There is a free annular central zone between the tapes astride the center plane of the tire.

Vehicle tires having a removable tread

A tubeless tire for a vehicle of the type adapted to be mounted on a one-piece undetachable rim of the drop-center type is provided. The tire is suitable for use with a rim having its bead-seats for the tire beads shaped like a truncated cone with the vertex axially turned towards the inside of the rim. The tire has beads having bead bases which are substantially frustum shaped for combining with the bead-seat of the rim. The angle of inclination of the beads is approximately the same as that of the bead seat. The tire beads are provided with reinforcing metallic wire cores which comprise a plurality of metallic turns closely wound together so as to constitute substantially a massive annular element that is circumferentially inextensible and has a cross-section of a polygonal shape. The core base is the radially innermost side of the polygon with respect to the tire. The element has an `undercut` which is the side of the polygon that has one end in common with the axially internal end of the core base, the dihedral angle defined by the core base with the `undercut` being between 90.degree. and 160.degree.. The polygon is an irregular polygon and the wire core is disposed in the bead of the tire with axially innermost extremity of the undercut passing through a plane perpendicular to the axis of rotation of the tire, passing through the axially innermost extremity of the bead-base.

Tire core bead for tubeless tires

A pneumatic tire having a radial carcass is provided with a reinforcing structure between the carcass and tread having first and second layers of metallic cords having an ultimate elongation of about 3%. The cords of the first and second layers are disposed parallel to each other and at angles of about 5.degree. to about 30.degree. with the axis of the tire body with the cords in one layer crossing the cords of the other layer. A third layer of metallic cords having an ultimate elongation of from about 4% to about 8% is disposed radially outwardly over the first two layers. The cords in the third layer are wound about the carcass in a plane which is substantially parallel to the longitudinal direction of the tire. The resulting assembly of layers provides a reinforcing structure which is adapted to withstand the tension stresses exerted on tires used on heavy vehicles such as buses and trucks even at high speed, giving also high steering characteristics to the tire.

Radial tire for motor vehicles

A pneumatic tire for vehicles has a tread band provided with grooves which extend circumferentially about the tire. The grooves are formed by a series of substantially rectilinear sections which are disposed at a predetermined angle with the equatorial plane of the tire and intersect to impart a zig-zag arrangement to the grooves about the tire. The intersections between said groove sections are situated in planes parallel to the equatorial plane of the tire, and each tread surface portion between one of the parallel planes and a pair of adjacent sections of a groove is shaped so the distance at its points from the tire axis gradually decreases from the parallel plane toward the region in which the sections of the pair of adjacent sections intersect.

Pneumatic tire for vehicles having improved handling and road gripping

A pneumatic tire for a vehicle wheel using a flanged rim has a bead structure which provides for a gradual decrease in rigidity between the area of the bead and the sidewall of the tire. The bead has an annular wire, at least one ply of the carcass wound about the wire and extending axially therefrom into the sidewall of the tire and a rubber filler filling the space between the turned-up portion of the ply and that portion on the opposite side of the annular wire. An annular fabric member is disposed over the turned-up portion of the carcass ply and extends beyond the end of the carcass ply into the sidewall of the tire. The rigidities of the metallic fabric and of the filler are balanced against each other so that the rigidity in the bead area of the tire gradually decreases from the bead into the sidewall of the tire. The filler is rubber having a Shore A hardness between 70.degree. and 80.degree. or 100% modulus between 65 and 85 kg/cm.sup.2. The metallic fabric has its cords disposed in a high elongation lang lay. The metallic cords in the fabric are disposed at an angle of between 15.degree. and 45.degree. with respect to the circumferential direction of the tire. Preferably the metallic fabric has about 41/2 cords per cm.

Growing community of inventors

Milan, Italy

Luigi Maiocchi