Abstract: Mould parts of a mould for vehicle tyres, such as sector matrices in a centripetal mould, are made by sintering of a metal- or ceramic-based powder (3) cyclically deposited in consecutively superposed layers. Deposition of each layer is followed by sintering of the powder by a laser beam (8) moving within previously defined areas delimiting contours of the sintered laminate portion thus obtained. Movement of the laser beam (8) is managed by a programmable electronic control unit (11) in which digital information defining the three-dimensional graphic representation of the mould portion to be obtained is stored. The digital information is processed for dividing the graphic representation into superposed layers corresponding each to one of the laminate portions to be obtained by sintering of the corresponding powder layer. Thus moulds of sintered material are obtained, which are provided with inner microcavities enabling air ejection during the tyre vulcanization.

Abstract: A tire for a wheel of a vehicle comprises a toroidal carcass provided with axially opposite sidewalls and beads for anchoring the tire to a rim of the wheel, a tread band located crownwise on the carcass, comprising a surface with a plurality of hollows and grooves defining a raised tread pattern, and a belt structure interposed between the carcass and the tread band, axially extending between the sidewalls. The tread band comprises at least first and second circumferential axially-contiguous portions arranged to contact a road surface. The first portion is formed of a first composition comprising a reinforcing filler having at least 40%-by-weight carbon black and at least some white filler, the second portion is formed of a second composition comprising a reinforcing filler having at least 20%-by-weight white filler, and the first composition is different from the second composition.

Abstract: Reinforcing fabric for articles made from elastomeric material, particularly for pneumatic tires, comprising a plurality of filamentary elements having at least tensile strength, parallel and adjacent to each other in a plane, lying in a predetermined direction. The reinforcing elements, preferably cords, are incorporated in an elastomeric material and constitute at most the 40% of the volume of the fabric.

Abstract: In a tire for motor-vehicles, an auxiliary support element (9) is interposed between a carcass ply (3) and a belt structure (6). The support element is employed during the manufacturing step of the belt structure (6) in order to stably retain, on the sectors of a comb drum (10), coils (7a) consecutively formed by winding of an inextensible cord (7) therearound. The auxiliary support element (9) is made in the form of an elastomeric sheet containing short aramid fibers in an amount included between 1 and 10 parts by weight per 100 parts of elastomeric material, to increase the stretchability of said element without impairing its adhesiveness. The introduction of the short aramid fibers in the blend enables the thickness of the auxiliary support element (9) to be reduced to about 0.075 mm.

Abstract: A high-transverse-curvature tire (1), in particular for mounting onto the rear wheel of motor-vehicles, comprises a tread band (8), coaxially extended around a belt structure (6), wherein a plurality of rubber blocks (10), defined between a plurality of grooves (1 1) extending along a direction substantially transverse to the tire running direction (D), are formed which grooves comprise a bottom (12) connected to opposite inlet (13) and outlet (14) sidewalls. In an equatorial zone (E) of the tread band (8), the inlet wall (13) of the grooves (11) is inclined with respect to the bottom (12) of the same towards the tire rolling direction, and forms an angle (&agr;) of from 50° to 80° with respect to a plane (&pgr;) tangent to the bottom (12).

Abstract: A tread for motor-vehicle tires has a raised pattern formed of a plurality of shaped blocks 7 distributed in circumferential rows 3, 4, 5, 6 disposed in parallel and in side by side relation. The number of the shaped blocks 7 arranged in each row gradually increases while moving from the equatorial plane X—X to the axial outer side edges 1a of the tread 1. Thus a gradual increase in the longitudinal stiffness of the shaped blocks 7 is achieved on passing from the side edges 1a of the tread 1 to the equatorial plane X—X, which brings about a reduction in the mobility of said blocks on the road contact patch and lower rolling noise.

Abstract: A process for producing a rubber compound for tires, where the ingredients of the rubber compound include: a polymer base containing an unsaturated chain which can be crosslinked with sulphur-based systems; at least one silica-based reinforcing filler; a silica-binding agent including a silane containing at least one sulphur atom; and a vulcanizing system. The process includes the steps of feeding the polymer base, the silica-based reinforcing filler, and the silica-binding agent ingredients continuously into a path for mixing and advancing an ingredient blend, wherein the mixing and advancing of the blend take place together. The path includes an initial stretch, an intermediate stretch, and a final stretch; each stretch defined between respective inlet and outlet sections.

Abstract: A tire (1) for motor-vehicle wheels comprises a tread band (10) and a belt structure (6), the tread band being molded with a raised pattern having a circumferential groove (11). In the absence of load and inflating pressure, the tire is characterized in that the belt structure in a cross-section of the tire has an axial profile comprising three distinct portions, first (14) and second (15) side portions and one central portion (16) interposed between the side portions. The side portions are concave at a radially internal position, in which the concavity is defined for each portion by a respective center and a respective radius of curvature. The central portion is concave at a radially external position where the concavity center of the central portion lies in the center line plane of the circumferential groove, in which the depth of the radially external concavity is canceled under the effect of the normal inflating pressure of the tire.

Abstract: A vulcanizable rubber composition is described comprising a cross-linkable unsaturated chain polymeric base, wherein is incorporated at least one organic compound, solid at room temperature, selected from the group comprising: amorphous or semicrystalline polymers, oligomers, low-molecular weight organic substances and mixtures thereof, which compound is substantially insoluble in the polymeric base and shows a first or second order transition temperature of from 80 to 160° C. Such rubber composition allows the manufacture of treads with either a low rolling resistance at the temperature of normal use of the tire (40°-70° C.), or a high grip when the tread is subjected to thermal stresses exceeding such temperatures.

Abstract: In a tire for motor-vehicles, an auxiliary support element (9) is interposed between a carcass ply (3) and a belt structure (6). The support element is employed during the manufacturing step of the belt structure (6) in order to stably retain, on the sectors of a comb drum (10), coils (7a) consecutively formed by winding of an inextensible cord (7) therearound. The auxiliary support element (9) is made in the form of an elastomeric sheet containing short aramid fibers in an amount included between 1 and 10 parts by weight per 100 parts of elastomeric material, to increase the stretchability of said element without impairing its adhesiveness. The introduction of the short aramid fibers in the blend enables the thickness of the auxiliary support element (9) to be reduced to about 0.075 mm.

Abstract: Process for the manufacture of a reinforcing fabric for articles made from rubber, such as pneumatic tires, conveyor belts, flexible tubes, and similar, comprising a plurality of metal cords orientated parallel to each other in a single direction and in which each cord comprises metal wires wound spirally around each other, wherein at least one of the wires of the cord consists of a shape memory material.

Abstract: A vulcanizable rubber composition for treads of vehicle tires, comprises:

Abstract: Reinforcing fabric for articles made from elastomeric material, particularly for pneumatic tires, comprising a plurality of filamentary elements having at least tensile strength, parallel and adjacent to each other in a plane, lying in a predetermined direction. The reinforcing elements, preferably cords, are incorporated in an elastomeric material and constitute at most the 40% of the volume of the fabric.

Abstract: A metal cord for reinforcing articles made from elastomeric material comprises a plurality of metal wires wound spirally around each other. At least one of the metal wires is formed from a shape memory material, has capacities of recovering a previously memorized shape, and is deformed from the memorized shape. The shape memory wire of the cord has the recovery capacities substantially active in a first heat cycle and degraded to at least a significant predetermined extent after the first heat cycle. One or more such metal cords may be incorporated in pneumatic tires, reinforcing fabric, and other articles, including by means of processes described herein.

Abstract: A tire tread band for medium/heavy duty motor-vehicles having circumferential grooves confining three pairs of respectively center, intermediate and shoulder ribs. Respective tread blocks are defined along the center and intermediate ribs and they are confined by transverse cuts. The center cuts impart a cusp-shaped end conformation and a hollow-shaped end conformation to the respective blocks, and the shapes of said end portions mutually match. The intermediate cuts run in the linear extension of the center cuts to give the respective blocks a rhomboidal configuration. The tire can be alternately associated with a driving axle or a driven axle, by merely reversing its direction of rotation, so that the following results are selectively achieved: an increase in the traction capability by the intermediate blocks or an increase in the directional capability as a result of the mutual wedging between the center blocks at the ground-contacting area.

Abstract: A method of foreseeing and controlling wearing in the tread of a tire based on the use of cuts of a limited depth (in the order of tenth parts of one millimeter) formed on the external surface of the tread, in the thickness of the elastomeric 7 material. The cut is preferably made by a laser beam. Rotation of the tire on a road or on any other friction surface enables both the uneven wearing of the tread, highlighted by localized spots devoid of cuts, to be quickly verified by inspecting the maintenance state of said cuts, and the wear rate of the tread, which can be drawn from calculation of the time elapsing between the disappearance of two groups of cuts of different depth.

Abstract: In a process for producing a vulcanizable rubber composition containing silica and having a low content of carbon black, at least a silica-based reinforcing filler and ad least a silane-based coupling agent are added to and intimately mixed with other ingredients of the composition in subsequent steps, at a temperature of from 165.degree. and 180.degree. C. and between 110.degree. and 160.degree. C. respectively. The rubber composition so obtained has an improved silica dispersion, constant physico-mechanical characteristics and a better drawability and is particularly suitable for the manufacture of treads for tyres with low rolling resistance.

Abstract: The described tread band (1) has laterally opposite transverse channels (6), each having a substantially rectilinear end stretch (6a) extending with an appropriate inclination from a respective outer side edge (1a), a connecting stretch (6c) of curvilinear extension and an inner end stretch (6b) terminating beyond the equatorial plane (X) and having a slightly inclined orientation relative the latter. The connecting stretch (6c) of each transverse channel (6) opens into the connecting stretch of a laterally opposite transverse channel, to define a transverse groove (3) of undulated extension. Also provided are two longitudinal grooves (2) consisting of substantially rectilinear stretches (2a) each extending between two transverse grooves (3) in a direction inclined to the equatorial plane (X). L-shaped auxiliary channels (8) are interposed in an alternate sequence relative to the transverse channels (6) defining grooves (3).

Abstract: A method and apparatus for applying a ribbon-like coating structure to the outer surface of a tire bead core. A bead core (2) is coaxially placed around a support drum (6) carrying an inflatable air bag (7) disposed in a deflated condition. Clasping sectors (14) circumferentially distributed in the drum are radially moved close to the inner surface of the bead core (2) to make a central portion of a ribbon-like coating structure (3) arranged about the inflatable air bag (7), adhere against the bead core itself. The air bag is inflated so as to form, on opposite axial sides relative to the bead core (2), two lobes (17, 18) each of them being enclosed between the outer surface of the drum (6) and a respective annular opposition bell (19, 20) coaxially encircling the drum. By axially moving the opposition bells (19, 20), a first and a second side flap of the coating structure (3) are applied to respective surfaces of the bead core (2).

Abstract: In a vulcanization mold (2) for vehicle tires the rubber blend deposits are cleaned off by the action of one or more laser beams (9) supplied in the form of short-duration and high-energy pulses, which beams cause separation of the rubber blend by effect of the shock wave generated by them and hitting the operating surfaces of the mold (2). Each laser beam (9) is guided by a scanning unit (21a, 21b) mounted on a rotating column (16) for distributing the beam action over the whole circumferential extension of the mold.