Abstract: A device (20) for continuously measuring deformations in a tyre (1), which is mounted on a rim (5), comprises at least one first emitter (7) of a first direct light beam (8), at least one first optical sensor (9) of the luminous intensity and at least one first reflecting element (13; 113) applied to a first portion (21) of an inner surface (4) of the tyre (1); the first emitter (7) is mounted on the rim (5) and is capable of sending the first direct light beam (8) towards the first reflecting element (13; 113); the first optical sensor (9) is also mounted on the rim (5) and is capable of receiving a first reflected light beam from the first reflecting element (13; 113), measuring a first prechosen physical parameter associated with the first reflected light beam and providing a first signal representing the deformation affecting the tyre (1) along the first surface portion (21) during one revolution of the tyre (1).

Abstract: A method for monitoring the instantaneous behavior of a tire includes the steps of acquiring and storing at least one basic reference curve representing variation of a displacement of at least one specified point of the tire in at least one of three spatial directions as a function of a spatial position of the at least one specified point during at least one portion of a revolution of the tire, continuously acquiring first signals representing the spatial position of the at least one specified point, deriving from the spatial position signals of the at least one specified point at least one cyclic curve of current operating displacement in at least one spatial direction, continuously comparing the at least one cyclic curve of current operating displacement with the at least one basic reference curve, and emitting a second signal depending on results of the comparison. A related device is also disclosed.

Abstract: A tyre comprises a casing ply having a meridian profile with a central crown portion and two sidewall portions; in the inflated configuration of the tyre, the crown profile portion has a radius of meridian curvature &rgr;c in the range from 406 mm to 690 mm and each sidewall profile portion forms an angle &agr;s with the axis of rotation of the tyre in the range from 25° to 30°; additionally, a mould for a tyre has cheek profiles which have a first and a second radius of curvature Rfs/Rfi whose ratio Rfs/Rfi ranges from 0.45 to 0.56 and a base profile of one sector having a radius of meridian curvature R≧500 mm and a shoulder angle &agr;0≧42°.

Abstract: A method for determining preselected performance characteristics of a tread of a tire consists in dividing the tread in a grid of cells forming piles of cells which are full, empty or partially full; identifying a group of piles of cells in each contact area; determining longitudinal stiffness values cxj and transversal stiffness values cyj for each pile; identifying families of discrete areas and transversal strips in each contact area; determining, for each strip, forces per unit of length by means of cxj and cyj, longitudinal stiffness values per unit of length cpx and transversal stiffness values per unit of length cpy and by means of cpx and cpy and a preselected state of deformation; determining total forces associated with all contact areas by means of single forces associated with the discrete areas, and evaluating their pattern so as to establish whether the arrangement of full and empty cells optimizes the performance characteristics of the tread.

Abstract: The invention relates to a method, a system and a pneumatic wheel for measuring the deformations of the casing of a tyre in operation, for the purpose of taking appropriate corrective action on the vehicle driving and/or control system by comparing the said measured deformations with predetermined values of the deformations.

Abstract: A mould for producing a tire includes a crown and at least two cheeks. The crown includes radially-movable sectors. A first cheek is axially opposite a second cheek. The mould includes a main profile in a plane of a meridian section. The main profile includes a maximum chord, a maximum height measured from a fitting line, a profile of the first and second cheeks, and a base profile of a sector. The base profile includes first and second lateral portions, first and second connecting portions, and a central portion. The first lateral and connecting portions are axially opposite the second lateral and connecting portions. Each cheek profile includes first and second portions including first and second radii of curvature, where a ratio of the first radius of curvature to the second radius of curvature is greater than or equal to 0.45:1 and less than or equal to 0.56:1.

Abstract: A method for monitoring the instantaneous behavior of a tire includes the steps of acquiring and storing at least one basic reference curve representing variation of a displacement of at least one specified point of the tire in at least one of three spatial directions as a function of a spatial position of the at least one specified point during at least one portion of a revolution of the tire, continuously acquiring first signals representing the spatial position of the at least one specified point, deriving from the spatial position signals of the at least one specified point at least one cyclic curve of current operating displacement in at least one spatial direction, continuously comparing the at least one cyclic curve of current operating displacement with the at least one basic reference curve, and emitting a second signal depending on results of the comparison. A related device is also disclosed.

Abstract: Method for vulcanizing a tire by predetermining a degree of vulcanization, comprising the steps of determining specified structural and dimensional parameters of the tire and of a vulcanization mould, determining the change over a time (t) of specified thermodynamic parameters of the tire, of the mould, of heat-supply fluids and of a cooling fluid, determining a parameter consisting of an equivalent vulcanization time t0, and determining an equivalent degree of vulcanization X(t0) at specified points within the tire by means of an equivalent isothermal rheometric curve at a reference temperature T0, comprising three consecutive sections having the following equations: X ⁡ ( t o ) = { k ⁢   ⁢ t o

Abstract: A method and a device for reducing the internal noise of a vehicle produced during the rolling of the tire are described The device comprises a plurality of elements made from open-cell expanded materials, for example expanded polyethylene, or from fibers of the mineral or textile type. These elements are introduced into the tire during its mounting on the corresponding rim and are placed in the absence of restraints in the annular cavity delimited between the tire and the rim. As a result of the rolling of the wheel, the various elements, under the action of the centrifugal force, are moved and pushed in a random way towards the inner surface of the tire, producing a ragged surface whose presence, in combination with the open cells of said elements, modifies and damps the acoustic waves generated inside the tire during the rolling of the tire.

Abstract: A method for determining preselected characteristics of a tread of a tire comprises dividing the tread into a grid of cells forming piles of full, empty and partially full cells and grouped into strips of preselected dimensions; associating with each strip of piles of cells a stiffness value K which is linearly bound to the number n of consecutive piles of full cells by means of an angular coefficient m, which, in turn, is linearly bound to the total number i of empty cells contained in two piles of partially full or empty cells delimiting the consecutive piles of full cells; determining at least one single force F for each strip by means of the stiffness value K, a preselected deformation state and the total transversal and longitudinal forces Ft, associated with all contact areas to evaluate whether they assume values which optimize at least one preselected performance characteristic of the tread (FIG. 2).

Abstract: A method for determining the road handling of a tire, comprising descriptions of the tire by means of a first, concentrated-parameter, physical model and by means of a second, finite-element model, a simulation on the second, finite-element model of a selected series of dynamic tests and an application to the first physical model of equations of motion suitable for representing the dynamic tests in order to obtain first and second frequency responses of selected quantities; a comparison between the first and second frequency responses of the selected quantities for determining the concentrated parameters of the first physical model and physical quantities indicative of the drift behavior of the tire.

Abstract: A method for determining the road handling of a tire, comprising descriptions of the tire by means of a first, concentrated-parameter, physical model and by means of a second, finite-element model, a simulation on the second, finite-element model of a selected series of dynamic tests and an application to the first physical model of equations of motion suitable for representing the dynamic tests in order to obtain first and second frequency responses of selected quantities; a comparison between the first and second frequency responses of the selected quantities for determining the concentrated parameters of the first physical model and physical quantities indicative of the drift behaviour of the tire.

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 method for determining the road handling of a tire, comprising descriptions of the tire by means of a first, concentrated-parameter, physical model and by means of a second, finite-element model, a simulation on the second, finite-element model of a selected series of dynamic tests and an application to the first physical model of equations of motion suitable for representing the dynamic tests in order to obtain first and second frequency responses of selected quantities; a comparison between the first and second frequency responses of the selected quantities for determining the concentrated parameters of the first physical model and physical quantities indicative of the drift behavior of the tire.

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 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.

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.

Abstract: A tire for a vehicle, that is representable by a dynamic rigid-ring tire model with concentrated parameters, has construction features that are substantially equivalent to concentrated parameters that fall within the following intervals corresponding to preselected indices of comfort:rb=100-300 (Ns/m)rbt=2-40 (Nms/rad)rcz=100-350 (Ns/m)rct=10-90 (Nms/rad)Ckx=18,000-70,000 (N),where rb is a radial foundation dampening of said dynamic tire model; rbt is a torsional foundation dampening of said dynamic tire model; rcz is a residual radial dampening of said dynamic tire model; rct is a residual torsional dampening of said dynamic tire model; and Ckx is a slipping stiffness of a brush model of said tread.

Abstract: An apparatus for testing a test wheel, provided with a tire and a rim, by passing the wheel over an obstacle. The apparatus including a road-wheel, a steering knuckle capable of rotatably supporting a hub and the test wheel, and two suspension arms supporting the steering knuckle. The apparatus also comprises a first, second, third and fourth leaf spring connected to the suspension arms and to a supporting frame, a fifth leaf spring connected to the steering knuckle and to the supporting frame, and a pneumatic spring in engagement with the steering knuckle and with the supporting frame. First and second acceleration transducers associated with the hub provide measurements of natural frequencies and dampenings of the tire in a radial and in a longitudinal direction. The apparatus can be used both in a movable-hub mode and in a fixed-hub mode.

Abstract: A method of control to determine the comfort level of a tire of a wheel for a vehicle is based on a dynamic tire model with a rigid ring having concentrated parameters that represent construction characteristics of the tire. Some concentrated parameters are measured, others are determined by parametric identification through a test of passing over an obstacle of the tire. From testing eight curves of natural frequencies and dampenings are obtained that are compared with as many calculated curves obtained from the model. By checking the coincidence between the eight calculated curves and the eight experimental curves, the values of the other concentrated parameters are determined that cause the calculated frequencies and dampenings to coincide with the experimental ones.