EP4532229A1

EP4532229A1 - Tyre comprising a monitoring device

Info

Publication number: EP4532229A1
Application number: EP23733803.3A
Authority: EP
Inventors: Cristiano Puppi; Andrea NATTA; Simone VIGNA
Original assignee: Pirelli SpA; Pirelli Tyre SpA
Current assignee: Pirelli and C SpA; Pirelli Tyre SpA
Priority date: 2022-05-27
Filing date: 2023-05-25
Publication date: 2025-04-09
Also published as: WO2023228224A1

Abstract

Tyre (99) comprising a monitoring device (1 ), wherein the monitoring device (1 ) comprises an electronic unit (3) and an electric power supplier (4) electrically connected to each other, wherein the electronic unit (3 ) comprises at least one sensor (5) for detecting at least one of the following physical quantities: temperature, pressure, acceleration, deformation; a processing unit (6); a transceiver (7), wherein the monitoring device (1 ) comprises a rigid printed circuit board (8) comprising a first face (9) and a second face (10) opposite to each other, wherein the monitoring device (1 ) comprises at least one adhesive layer (20) proximal to the second face (10) for fixing the rigid board (8) to an inner surface (2) of the tyre (99), wherein the electronic unit (3) and the electric power supplier (4) are both fixed onto the first face (9) of the rigid board (8).

Description

DESCRIPTION

Title: TYRE COMPRISING A MONITORING DEVICE

Technical field of the invention

The present invention relates to a tyre comprising a monitoring device, for example suitable for detecting at least one physical quantity among temperature, pressure and acceleration/deformation.

State of the art

Typically, a tyre has a substantially toroidal structure around an axis of rotation thereof during operation, and it has an equatorial plane perpendicular to the axis of rotation, said equatorial plane being typically a plane of (substantial) geometric symmetry (e.g. neglecting any minor asymmetries, such as the design of the tread and/or the writings on the sidewalls and/or the inner structure).

By "inner cavity" it is meant the space bounded by the inner surface of the tyre and the surface of the mounting rim which faces the inner surface of the tyre, when fitted.

By "crown portion" it is meant the portion of tyre placed at the tread band.

The terms "radial" and "axial" are used with reference respectively to a direction perpendicular and to a direction parallel to the axis of rotation of the tyre.

The term "tangential" is used with reference to a direction generally directed according to the rolling direction of the tyre, perpendicular to both the radial direction and the axial direction.

By "footprint" it is meant the portion of outer surface of the tread band which, during the rolling of the tyre fitted and subjected to a load (for example due to the fitting on a vehicle), is in contact at every moment with the rolling surface. The footprint typically has substantially null curvature (or substantially infinite curvature radius), or in any case it substantially assumes the conformation of the rolling surface. By "footprint portion" it is meant the part of the crown portion corresponding to the footprint.

There have been proposed tyres for vehicles comprising monitoring devices of one or more physical quantities arranged in the inner cavity of the tyre, for example as described in WO 2019/123118 A1 , WO 2020/026281 A1 , WO 2020/026282 A1 , WO 2020/026283 A1 . of the invention

In the context of tyres comprising monitoring devices arranged in the inner cavity of the tyre, the Applicant has faced the problem of making a monitoring device of at least one physical quantity (for example temperature, and/or pressure and/or acceleration and/or deformation) to be arranged directly in proximity of the inner surface of the crown portion of a tyre, highly reliable over time (e.g. in terms of loss of structural and/or functional integrity of the tyre and/or of the monitoring device), even at very high speed of rotation of the tyre, and at the same time industrially optimized and with low production cost.

According to the Applicant, the aforesaid problem is solved by a monitoring device comprising an electronic unit (comprising at least one sensor, a processing unit and a transceiver) and an electric power supplier (e.g. generator and/or accumulator) electrically connected to each other and both fixed to a same face of a rigid printed circuit board.

According to an aspect, the invention relates to a tyre comprising a monitoring device. The monitoring device comprises an electronic unit and an electric power supplier electrically connected to each other.

The electronic unit comprises at least one sensor for detecting at least one of the following physical quantities: temperature, pressure, acceleration, deformation; a processing unit; a transceiver.

The monitoring device comprises a rigid printed circuit board comprising a first face and a second face mutually opposite.

The monitoring device comprises (at least) one adhesive layer proximal to said second face for fixing said rigid board to an inner surface of said tyre at a crown portion of said tyre.

Said electronic unit and said electric power supplier are both fixed onto said first face of said rigid board.

By 'electric power supplier' it is meant a component structured for supplying electric power, whether the power provided is pre-accumulated (as in accumulators, e.g. the batteries or the capacitors), or whether the power provided is generated and/or received on site in real time (as for example in power recovery devices, or 'energy harvesting', combined or not with power accumulators).

The fact that the electronic unit and the electric power supplier are both fixed onto the same face of the rigid board, makes the electronic unit and the electric energy supplier to be mutually arranged side by side with respect to the inner surface of the tyre. In other words, the two elements are not radially overlapping to each other, so that the respective masses are not located at the same point of the inner surface of the tyre.

The Applicant has found that in this way the overall mass of the monitoring device is spatially distributed (on the inner surface of the tyre) in at least some parts having a non-negligible mass with respect to the overall mass of the device, thus reducing the mass which insists on a respective single localized region of crown portion of the tyre. The Applicant has in fact observed that in the entry and exit areas from the footprint, due to the corresponding deformation undergone by the tyre, the instant radial acceleration of the tyre portion (and therefore of the monitoring device) which passes through the entrance and the exit of the footprint is greater than the acceleration undergone by the same portion (and respectively by the device) at the zones outside the footprint. Furthermore, in the footprint region, while the radial acceleration is zeroed, appears a tangential acceleration which follows, along the footprint, a sinusoidlike trend.

According to the Applicant, the acceleration with its rapid and intense variation at high- frequency cycles generates significant cyclic stresses, in radial direction (such as a 'hammering') and in tangential direction (shearing), caused by the mass of the monitoring device on the structures of the tyre and/or vice versa. At very high rotation speed, these stresses can generate significant and localized overheating of the monitoring device and/or of the tyre at the point of application of the monitoring device. This overheating and these mechanical stresses, and/or the combination of the two effects, can lead to a damage to the monitoring device, relatively to its structural and/or functional integrity, and/or to its coupling with the inner surface of the tyre (for example decomposition and/or detachment of the adhesive). In more serious cases, the overheating and the mechanical stresses, and/or the combination of the two effects, can lead to the loss of structural integrity of the crown portion of the tyre, even up to the formation of holes (so-called "blisters") at the tread band, caused by the localized decomposition of the compound of the tyre subsequently removed due to the rotational movement of the latter and/or to the delamination of the tread, in particular of one or more of the ribs of the tread (e.g. of the central and/or lateral circumferential relief, according to the camber angle of the tyre).

The Applicant has therefore realized that, by limiting the mass of the monitoring device which insists on a given localized region of the tyre, the aforementioned hammering and shear stress phenomena and the consequent overheating of the crown portion and/or of the adhesive and/or of the monitoring device can be reduced, thus being able to obtain a desired reliability over time of the monitoring device and/or of the tyre in terms of resistance to high speed and/or to cyclic stresses (e.g. fatigue resistance).

The Applicant has surprisingly found that the aforesaid positive effects (i.e. reduction of the stresses and of the overheating) obtainable thanks to the aforesaid spatial arrangement of the electronic unit and electric energy supplier are further increased in a synergistic way by the fixing of the aforesaid two elements on a single (e.g. in single piece) rigid board.

Without wishing to limit itself to any theory, the Applicant considers in fact advantageous the use of a rigid printed circuit board, such as a board for electronic circuits made by "rigid printed circuit board" technology - or "rigid-PCB". The rigid board, in addition to being easy and cheap to find, allows, thanks to its substantial rigidity (e.g. such that the board does not undergo substantial deformation when subjected to the stresses generated in the normal operating conditions of the tyre on which it is applied) and to the relatively large surface, to distribute over a greater area, and to effectively resist to, the substantially localized stresses generated by the electronic unit and/or by the electric power supplier following the rotation of the tyre, thus reducing the stresses transferred to the interface between monitoring device and tyre.

By "rigid board" it is meant, for example, a board made with a material (including a composite/layered material) which, if used for making a square-shaped plate with side significantly greater than the circumferential extension of the entry or exit area from the footprint area of a tyre (for example a plate of surface 120 mm x 120 mm) and with thickness equal to the board, allows this plate to conform - at room temperature - to a cylindrical surface with radius of 50 mm only after breakage, even only partial, for example at a face of the plate opposite to the cylindrical surface, and/or a permanent deformation.

Furthermore, an element such as the rigid board is capable by itself of supporting high mechanical stresses.

The use of a rigid printed circuit board allows to make in simple way the electric circuit on the board itself, as well as the fixing of the electronic components, which can for example be done by means of common welding (e.g. tin soldering), and increases the reliability over time of the electrical circuit and/or of the fixings as regards the possibility of failure due to detachment of the components and/or interruption of the electric tracks. In fact, the rigid board substantially avoids that the conductive tracks deform cyclically, e.g. by flexion, torsion or extension/contraction, preventing the consequent interruption of the circuit.

Furthermore, the robustness of the rigid board allows the latter to support larger (with greater capacity) electric energy suppliers (e.g. batteries), with consequent advantage in the operating life of the monitoring device.

In conclusion, the Applicant has surprisingly found that the aforesaid advantages, made through the use of a rigid board and the fixing of the two aforesaid elements onto the same face of the rigid board side by side, compensate, up to overcoming, any negative effect consequent to the mass of the rigid board.

The present invention can have one or more of the following preferred features. Preferably said rigid board has elongated shape having a main development direction, more preferably rectilinear. Preferably a dimension of said rigid board along said main development direction is greater than or equal to 1 .5 times, more preferably 2 times, a dimension of the rigid board along a direction perpendicular to said main development direction. In this way the extension of the rigid board and/or its mass is limited only to what is necessary.

Preferably said electronic unit comprises electronic components at least in part spatially distributed onto a portion of said first face of the rigid board left free by said electric power supplier.

Preferably said electric power supplier is arranged at least in part at an end portion of said rigid board with respect to said main development direction. In this way the remaining space of the rigid board can be intended for the fixing of the electronic unit, thus obtaining the spatial side by side arrangement of the two elements.

Preferably said electric power supplier is an electric energy accumulator.

Preferably said electric power supplier comprises at least one battery (e.g. a button cell battery).

In one embodiment, said electric power supplier comprises a pair of batteries. The two batteries can be for example arranged mutually opposite to each other along the main development direction of the rigid board. In this way the mass is balanced and efficiently distributed, with the electronic unit interposed between the two batteries along said main development direction. Preferably said rigid board has thickness (e.g. along the radial direction) greater than or equal to 0.7 mm, more preferably greater than or equal to 1 .0 mm, and/or less than or equal to 3.0 mm, more preferably less than or equal to 2.0 mm. These thicknesses contribute to the desired rigidity of the board without exceeding the weight.

Preferably said rigid board comprises a laminated layer comprising one or more layers of a base material, such as cellulose-based sheets (e.g. paper), glass fiber (cross- fibered or not), etc., impregnated with a resin (e.g. phenolic, epoxy, polyamide, or BT/epoxy). In this way the desired rigidity and/or electrical insulation is conferred.

Preferably the laminated layer comprises one or more layers of glass fiber impregnated with an epoxy resin (for conferring resistance to high temperatures, e.g. above 100°C). Preferably said rigid board comprises a plurality of electric coupling regions arranged at said first face. Typically, the electric coupling regions are suitably connected to each other by a plurality of electrically conductive metal tracks. In this way the board is prepared to house the electronic components and the electric power supplier.

Preferably said metal tracks are partially arranged inside said laminated layer. In this way it is conferred strength and protection to the tracks, further improving the reliability of the electrical circuit.

Preferably said at least one sensor, said processing unit and said transceiver are fixed to said first face by welding at respective electric coupling regions. This technology offers great reliability and prompt availability.

Preferably said electric power supplier (preferably each battery) is fixed to said first face by gluing with a conductive glue interposed between a first pole of said electric energy supplier (preferably a first face of each battery facing said rigid board) and a first electric coupling region (arranged on said first face of said rigid board). In this way the electric power supplier is fixed to the rigid board and at the same time the electric contact is realized. The use of the conductive glue also allows to avoid the use of an electric connection metal tab arranged between the supplier and the first face of the rigid board, which introduces a thickness typically with surface extension less than an extension of the first pole of the supplier, thus generating a possible fixing instability of the supplier.

Preferably said monitoring device comprises a metal tab which electrically connects a second pole of said electric power supplier (preferably a second face of each battery facing away from said first face of said rigid board) to a second electric coupling region (arranged onto said first face of said rigid board). Preferably said metal tab is connected to said second pole and to said second electric coupling region by conductive glue. In this way the electric power supplier is further fixed and the closing of the circuit is provided.

In general, the use of the conductive glue for fixing the electric power supplier and at the same time for making the electric contact is particularly advantageous, with respect to a common welding (e.g. selective soldering).

In fact, in the common welding process of the battery to the rigid printed circuit board, it can happen that the tabs of the battery (provided at the origin by the battery manufacturer) contact conductive regions of the rigid board before the welding is completed, causing the instant powering to the circuit, which in turn can cause damage to the circuit and/or to the electronic components, especially if this occurs when the monitoring device is subjected to the high temperatures of the welding oven.

In the case of the conductive glue instead, since it typically does not conduct (and therefore does not power the electronic components) until it is polymerized by means of heat, the aforementioned phenomenon of involuntary instantaneous powering of the circuit is entirely eliminated. In fact, by means of the conductive glue, the circuit is progressively powered as the glue polymerizes.

Preferably a surface extension (in top view) of said first pole of the electric power supplier is greater than a surface extension (in top view) of said second pole of said electric power supplier. In this way the adhesion and/or the electric contact of the supplier to the rigid board is improved. In the case of a button cell battery, the pole having greater surface extension is typically the positive pole.

Preferably said monitoring device comprises a protective layer which covers said electronic unit and said electric power supplier with continuity, and more preferably it extends over a whole surface extension of said first face of said rigid board. In this way the components, the electrical connections between the components and, preferably, also the remaining part of the first face of the rigid board are protected.

In one embodiment said protective layer is made of laminated material (e.g. of polyamide or polyurethane).

In one embodiment said protective layer is made by spraying a fluid polymeric mixture (e.g. silicone or polyurethane) and subsequent solidification of said mixture.

In one embodiment said monitoring device comprises a containment body which at least partially (more preferably entirely) realizes said protective layer.

Preferably said containment body is in single piece. In this way the protection is improved.

In one embodiment said containment body is open at (a whole surface extension of) said second face. In other words, the containment body does not cover the second face of the rigid board. In this way the overall weight of the containment body is reduced.

Preferably a base surface of the containment body is arranged flush with, and entirely surrounds, the second face. In this way the base surface and the second face realize a common surface (preferably flat), to the advantage of the arrangement of the adhesive layer and of the robustness of the fixing of the containment body.

In one embodiment said containment body entirely encapsulates said electronic unit, said electric power suppler and said rigid board with continuity. In other words the containment body makes a casing (substantially entirely) closed which entirely contains the rigid board, the electronic unit and the electric power supplier. In this way the protection afforded to the electronic/electric components and to the rigid board is further enhanced.

Preferably said adhesive layer is arranged in (direct) contact with a base surface of said containment body. In this way the body of containment is fixed and, consequently, also the rigid board.

In the embodiment in which the containment body is open at the second face, the adhesive layer is preferably arranged in (direct) contact also with said second face. Preferably said adhesive layer has a top view extension which exceeds a top view extension of the rigid board, more preferably along a whole edge of the rigid board. In this way the absorption of the stresses (particularly in extension and/or compression) and/or the reduction of their transmission to the rigid board is further improved.

Preferably a base surface of said containment body has a top view contour (more preferably a shape) substantially equal to a top view contour (more preferably a shape) of said adhesive layer. In this way the fixing of the device to the tyre is improved.

In one embodiment said containment body is made of polymeric material, preferably thermoplastic, for example polyamide, or thermosetting, for example polyurethane. In this way it is cheap, easy to produce and structurally robust.

Preferably said containment body is suitable for resisting at high temperatures, e.g. greater than or equal to 70°C, more preferably greater than or equal to 100°C. In this way the resistance to internal operating conditions of the tyre is improved.

Preferably said adhesive layer is in single piece. In this way the qualities of adhesion and/or absorption of the stresses are improved.

Preferably said adhesive layer comprises (more preferably consists of) a decoupling element, said decoupling element preferably being a double-sided adhesive tape comprising (i) a viscoelastic acrylic foam, or (ii) a substrate of expanded polymeric material (such as for example EPDM rubber or polyurethane, or also in the form of a gel), or (iii) at least one layer of acrylic adhesive (or even a combination of the elements (i), (ii) and (iii)). In this way the adhesive layer is able to absorb the stresses (e.g. in extension and/or in bending) caused by the cyclic deformation of the tyre, reducing, even eliminating, their transmission to the containment body and/or to the rigid board (which as rigid, it could be undergone damage by such stresses). In this way, the adhesion to the tyre of the monitoring device is improved, even for very high rotation speed of the tyre.

Preferably said adhesive layer has thickness (e.g. along the radial direction) greater than or equal to 0.5 mm, more preferably greater than or equal to 1 .2 mm, and/or less than or equal to 2.5 mm, more preferably less than or equal to 2 mm. Such thicknesses are advantageous to the aforementioned absorption of the stresses.

In one embodiment (preferably when said electric power supplier comprises one and only one battery), a length of the rigid board along the main development direction is greater than or equal to 35 mm, more preferably greater than or equal to 40 mm, and less than or equal to 55 mm, more preferably less than or equal to 50 mm. In this way sufficient space is created for the single battery and the electronic unit, without exceeding the dimensions of the board, to the advantage of the overall weight of the rigid board.

In one embodiment (preferably when said electric power supplier comprises a pair of batteries), a length of the rigid board along the main development direction is greater than or equal to 50 mm, more preferably greater than or equal to 55 mm, and less than equal to 80 mm, more preferably less than or equal to 75 mm. In this way sufficient space is created for both the batteries, without exceeding the dimensions of the board, to the advantage of the overall weight of the rigid board.

Preferably a width of the rigid board along a direction perpendicular to the main development direction is greater than or equal to 10 mm, more preferably greater than or equal to 18 mm, and less than or equal to 25 mm, more preferably less than or equal to 22 mm. In this way the extension of the board is further limited, to further advantage of the weight.

Preferably said at least one sensor is suitable for detecting at least two of the following physical quantities: temperature, pressure, acceleration, deformation, for example temperature and pressure. Even more preferably said at least one sensor is suitable for detecting temperature, pressure and acceleration. Preferably said at least one sensor is suitable for detecting at least said acceleration, more preferably at least a radial component and/or a tangential component of said acceleration. In this way the monitoring device provides data particularly useful for obtaining the state and/or functioning of the tyre and/or the behaviour of the vehicle on which it is fitted.

Preferably said transceiver comprises a dipole antenna. The surface extension of the rigid board, in particular in the case in which the electric power supplier comprises the pair of batteries, is particularly suitable for the adoption of such antennas. In this way data transmission is improved, in particular in the frequency range used by Bluetooth or WiFi devices, e.g. between 2 and 5 GHz, which can be particularly advantageous for monitoring devices of the physical operational quantities of the tyres.

Preferably said monitoring device is fixed to the tyre in such a way that the equatorial plane of the tyre crosses said rigid board. In this way it is easy the application of the device in a portion of the tyre whose deformation is scarcely influenced by the variation of the motion conditions (e.g. drift angle, camber) and - therefore - of greater interest in case of measurements of signals from which detecting information on the state and/or instantaneous behaviour of the tyre during use.

Preferably said main development direction of the rigid board crosses said equatorial plane, more preferably it is (substantially) perpendicular to said equatorial plane. In other words the rigid board is preferably arranged with the main development direction substantially parallel to the axial direction. In this way the extension of the rigid board is limited in the circumferential direction, thus limiting the gradient of stresses (e.g. bending along the circumferential direction, extension, contraction, inertials, etc.) along the surface extension of the rigid board during the phases of entry and exit from the footprint area and/or the time duration in which the rigid board is subjected to these stresses. Preferably said monitoring device is arranged onto said inner surface of the tyre in so that said electronic unit (in particular the sensor) is substantially entirely contained in a projection, onto said inner surface, of a (maximum) encumbrance of a central rib (with circumferential development) of a tread of said tyre. In this way the sensor is suitably arranged for detecting the response of the tyre (e.g. temperature and/or acceleration) at a point in direct contact with the rolling surface (for example with respect to the grooves of the tread which do not contact the rolling surface), and therefore advantageously representative of the behaviour and/or of the state of the tyre.

In the embodiment in which said electric power supplier comprises one or more batteries, said monitoring device is preferably arranged onto said inner surface so that at least one battery (preferably each battery) is at least partially superimposed on a projection, onto said inner surface, of a respective (circumferential) groove of the tread, typically adjacent (e.g. along an axial direction of the tyre) to said central rib of the tread. This positioning is particularly advantageous since the mass of each battery (which typically constitutes one of the heaviest elements of the device) insists at least in part on a region of the tyre which can support high heating (and therefore a high stress from an element having non-negligible mass), for example if compared to the central rib. In fact, at the grooves, even if the greater mass of the accumulators generates greater stresses, the smaller amount of deformed compound results in less heat generated by deformation. Furthermore, at the grooves the tyre performs a better heat exchange with respect to the area at the ribs, precisely because of the lower thickness of the tread (and therefore of a lower thermal resistance).

Finally, since the regions of tread at the grooves do not typically contact the rolling surface during tyre rolling, these regions are not damaged by the combined action of thermal stress and friction with the rolling surface (the combination of which is instead typically responsible for the possible formation of blister phenomena at portions of the tread in direct contact with the rolling surface, such as the ribs).

Brief description of the drawings

- Figure 1 shows schematically and partially in cross-section a tyre comprising a monitoring device according to a first embodiment of the present invention;

- figures 2 and 3 schematically show respectively a lateral view section and a top view of the monitoring device of figure 1 ;

- figure 4 schematically shows a perspective and exploded view of the monitoring device of figures 2 and 3;

- figures 5 and 6 schematically show respectively a lateral section view and a top view of a second embodiment of a monitoring device according to the present invention. Detailed description of some embodiments of the invention

The features and the advantages of the present invention will be more apparent by the following detailed description of some embodiments, presented by way of non-limiting example of the present invention, with reference to the attached figures. In the present description and figures, the same reference number is used for the same elements, also in their embodiment variants.

In figure 1 with the number 99 is globally indicated a tyre exemplarily comprising a tread 90 having at least one central rib 91 (with circumferential development) and a pair of grooves 92 (with circumferential development) arranged on the sides of the central rib along an axial direction of the tyre.

The tyre 99 comprises a monitoring device 1 fixed to an inner surface 2 of the tyre 99 at a crown portion 93 of the tyre (fig. 1 ).

The monitoring device 1 comprises an electronic unit 3 and an electric power supplier 4 electrically connected to each other.

Exemplarily the electronic unit 3 comprises a sensor 5 for detecting at least one of the following physical quantities: temperature, pressure, acceleration, deformation.

By way of example, the sensor 5 can be a sensor model FXTH870911 DT1 marketed by NXP Semiconductors®, suitable for detecting three of the aforementioned physical quantities, specifically temperature, pressure and acceleration, in particular at least the radial component and the tangential component of the acceleration. Optionally (not shown) the sensor can in turn incorporate a respective processing unit.

The electronic unit further comprises a processing unit 6 and a transceiver 7. Exemplarily the transceiver 7 comprises a dipole antenna (not shown).

In the figures, the electronic unit 3, the sensor 5, the processing unit 6 and the transceiver 7 are exemplarily depicted in a purely schematic way. For the purposes of the present invention, the expression "electronic unit" does not necessarily mean a single electronic component, but can (more typically) identify the whole arrangement of the single electronic components fixed to the rigid printed circuit board at a portion of the first face left free by the electric power supplier 4 (as shown for example in fig. 4). To this regard figure 4 exemplarily shows the monitoring device 1 of figures 2 and 3 with a greater degree of detail.

Exemplarily the electric power supplier 4 is an accumulator of electric power. In the embodiment of figures 1 -4, the electric power supplier 4 exemplarily comprises a pair of batteries 40.

In the embodiment of figures 5 and 6, the electric power supplier exemplarily comprises one and only one battery 40.

Exemplarily each battery 40 is a button cell battery.

Exemplarily the button cell battery can be of the type CR2032, with 20 mm diameter and 3.2 mm thickness, with a mass of 3 g and electric charge of 200 mAh.

The monitoring device 1 further comprises a rigid printed circuit board 8, made in single piece. The rigid board comprises a first face 9 and a second face 10 mutually opposite. The electronic unit 3 and the electric power supplier 4 are both fixed onto the first face 9 of the rigid board 8.

Exemplarily the rigid board 8 has elongated shape having a rectilinear main development direction 101 , wherein a dimension of the rigid board 8 along the main development direction 101 is exemplarily greater than 2 times a dimension of the rigid board along a direction perpendicular to the main development direction.

In particular in the embodiment of figures 1 -4, a length L of the rigid board 8 (along the main development direction 101 ) is equal to about 65 mm and a width W (along the direction perpendicular to the main development direction 101 ) is equal to about 20.5 mm.

In the embodiment of figures 5 and 6, the length of the rigid board 8 is equal to about 45 mm and the width is equal to about 20.5 mm.

Exemplarily the electric power supplier 4 is arranged at least in part at an end portion 11 of the rigid board 8 with respect to the main development direction 101. In more detail, in the embodiment of figures 1 -4, the two batteries 40 are arranged for example opposite to each other along the main development direction 101 of the rigid board. As regards the embodiment of figures 5 and 6, the single battery 40 is arranged at respective end portion of the rigid board.

Exemplarily an edge of each end portion of the rigid board is substantially countershaped to a corresponding edge portion of the respective battery 40.

Exemplarily the rigid board 8 has thickness (perpendicularly to the first face) equal to about 1 mm (in the first embodiment) and equal to about 1.6 mm (in the second embodiment).

Exemplarily the rigid board 8 comprises a laminated layer comprising one or more layers (not shown) of a base material, such as cellulose-based sheets (e.g. paper), glass fiber (woven or not), etc., impregnated with a resin (e.g. phenolic, epoxy, polyimide, or BT/epoxy). Advantageously the laminated layer comprises one or more layers of glass fiber (with crossed fibers or not) impregnated with an epoxy resin.

Exemplarily the rigid board 8 is made by PCB ("Printed Circuit Board") technology, and comprises a plurality of electric coupling regions (not shown) arranged at the first face 9. For example, the electric coupling regions can be made of electrically conductive material, such as for example copper, and can be realized by an etching process (e.g. photo-etching, chemical etching, mechanical etching, etc.) starting from a continuous sheet of electrically conductive material arranged on the first face of the rigid board. Typically, this etching process removes the unnecessary electrically conductive material, leaving only that used for making the electric coupling regions (and eventually also electric connection tracks between the various regions, as described below).

Exemplarily the electrical coupling regions are suitably connected to each other by a plurality of electrically conductive metal tracks (not shown, e.g. made of copper).

Exemplarily the metal tracks are partially arranged inside the laminated layer. Part of the metal tracks is instead arranged externally to the laminated layer and it is realized by the aforementioned etching process of a metal sheet arranged at the first face of the rigid board.

Exemplarily the sensor 5, the processing unit 6 and the transceiver 7 are fixed to the first face 9 by welding (e.g. tin soldering), each at one or more respective electric coupling regions. Alternatively the sensor, the processing unit and the transceiver can be fixed to the first face by a conductive glue.

Exemplarily the electric power supplier 4 (i.e. each battery 40) is fixed to the first face 9 by gluing with a conductive glue 14 interposed between a first pole 16 of the electric power supplier (exemplarily between a first face of each battery 40 facing towards the rigid board 8) and a first electric coupling region (not shown) arranged on the first face of the rigid board. Advantageously, the first electric coupling portion can have circular shape for adapting to the circular profile of the button cell battery.

Exemplarily the monitoring device 1 also comprises a metal tab 15 which electrically connects a second pole 17 of the electric power supplier 4 (exemplarily a second face of each battery 40 facing away from the first face 9 of the rigid board) to a second electric coupling region (not shown) arranged on the first face of the rigid board. Exemplarily (not shown) the metal tab 15 is connected to the second pole 17 and to the second electric coupling region by conductive glue.

Advantageously, typically when the tyre is designed for limited maximum rotation speed, each battery 40 and each metal tab 15 can be fixed to the first face 9 by only conductive glue (i.e. it is possible to avoid the use of other types of glue, such as for example structural glue). Alternatively, typically for tyre sports applications (i.e. when the tyre is designed for high maximum rotation speed), it can be provided fixing each battery and each metal tab to the first face by both conductive glue and structural glue (for example by alternating spatial regions coated with conductive glue to spatial regions coated with structural glue).

Exemplarily a top view surface extension of the first pole 16 of the electric power supplier is greater than a top view surface extension of the second pole 17 of the electric power supplier (figs. 3 and 6). Exemplarily, the first pole 16 is a positive pole.

Exemplarily (fig. 2, 4 and 5) the monitoring device 1 comprises a containment body 18 in single piece which realizes a protective layer which covers the electronic unit 3 and the electric power supplier 4 with continuity. Figures 3 and 6 instead, do not show the containment body 18 for purposes of greater clarity (e.g. in order to show the electronic unit and the electric power supplier).

In both the shown embodiments, the containment body 18 exemplarily extends also over a whole surface extension of the first face 9 of the rigid board 8.

In the embodiment of figures 1 -4, the containment body 18 is open at a whole surface extension of the second face 10 (i.e. it does not cover the second face 10 of the rigid board, as shown in figure 2). In this embodiment a base surface 19 of the containment body 18 is arranged flush with the second face 10, entirely surrounding the second face (creating, together with the second face, a common plane surface).

In the embodiment of figures 5 and 6, the containment body 18 entirely encapsulates the electronic unit 3, the electric power supplier 4 and the rigid board 8 with continuity, realizing a closed casing (figure 5). In this embodiment, a base surface 19 of the containment body 18 exemplarily realizes a single continuous planar surface arranged below the second face 10 of the rigid board.

Exemplarily the containment body 18 is made of thermoplastic polyamide, or of thermosetting polyurethane.

For example the containment body can be made by a low-pressure injection moulding process by injection or casting of the material in fluid form (e.g. molten, if thermoplastic, or non-polymerized, if thermosetting) in a suitably shaped mould, and subsequent cooling (if thermoplastic) or heating (if thermosetting).

For this purpose, for example, the rigid board, together with the electronic unit and the electric power supplier (fixed on the first face and electrically connected to each other), can be inserted into the mould before the molding or casting process of the containment body. The polymeric material in fluid form can then be injected or casted into the mould directly onto the rigid board, the electronic components and the electric power supplier, and then let to solidify. In this way a complete coating of the components fixed to the rigid board is obtained at the respective portions not in direct contact with the rigid board (and advantageously also of the whole first face of the rigid board in the regions left free by the aforesaid components).

Eventually, for making the closed containment body of the embodiment of figures 5 and 6, it can be provided arranging the rigid board in raised position with respect to a support surface of the mould cavity, so as to allow the material in fluid form to distribute also below the rigid board in order to entirely cover the second face of the rigid board with continuity.

In one embodiment (not shown) the protective layer can be made of a laminated material (e.g. polyamide or polyurethane) which is adhered to the rigid board, the electronic unit and to the electric power supplier in order to coat these elements. For example, for adhering the laminated material to the rigid board and electronic components (including batteries) can be used a vacuum lamination process, wherein the material is first heated and then adhered to the elements to be coated by applying vacuum.

Exemplarily the monitoring device 1 comprises an adhesive layer 20 proximal to the second face 10 for fixing the rigid board 8 to the inner surface 2 of the tyre.

Exemplarily the adhesive layer 20 is arranged in direct contact with the base surface 19 of the containment body 18.

In the embodiment of figures 1 -4, the adhesive layer 20 is arranged in direct contact also with the second face 10 of the rigid board.

Exemplarily the base surface 19 of the containing body 18 has a top view shape substantially equal to a top view shape of the adhesive layer 20 (in both embodiments). Exemplarily the adhesive layer 20 is in single piece and has a top view extension that exceeds a top view extension of the rigid board 8 along a whole edge of the rigid board (in both embodiments).

In more detail, in both the shown embodiments the adhesive layer 20 protrudes of about 11 .5 mm from both sides of the rigid board along the main development direction 101 , and protrudes of about 4.25 mm from both sides from the rigid board along the direction perpendicular to the main development direction 101.

Exemplarily the adhesive layer 20 reproduces, with a scale factor, the top view shape of the rigid board.

In one embodiment (not shown) the adhesive layer reproduces the top view shape of the rigid board (i.e. without protruding below the rigid board).

In other embodiments, not shown, the adhesive layer can have any top view shape (e.g. circular, rectangular, multi-lobed, etc.).

Exemplarily the adhesive layer 20 comprises a decoupling element. Advantageously, the decoupling element is a double-sided adhesive tape comprising (i) a viscoelastic acrylic foam, or (ii) a substrate of expanded polymeric material (such as for example EPDM rubber or polyurethane, or also in the form of a gel), or ( iii) at least one layer of acrylic adhesive (or even a combination of the elements (i), (ii) and (iii)).

For example, the decoupling element can be represented by adhesive tapes 3M^TM VHB^TM of the family 4941 , of the family 4956 and of the family 5952.

Exemplarily the adhesive layer 20 has thickness (perpendicularly to the first face) equal to about 1 .60 mm (for both the shown embodiments).

With reference again to figure 1 , the monitoring device 1 is exemplarily fixed to the tyre so that the equatorial plane 100 of the tyre crosses the rigid board 8. More in detail, exemplarily the main development direction 101 of the rigid board 8 is substantially perpendicular to the equatorial plane 100.

Exemplarily the monitoring device 1 is arranged onto the inner surface 2 of the tyre 99 so that the electronic unit 3 (in particular the sensor 5) is substantially entirely contained in a projection, onto the inner surface 2, of an (maximum) encumbrance of the central rib 91 of the tread 90 of the tyre.

Furthermore, the monitoring device 1 of figure 1 is exemplarily arranged onto the inner surface 2 so that each battery 40 is at least partially superimposed on a projection, onto the inner surface 2, of a respective circumferential groove 92 of the tread.

In the case of the fixing (not shown) of the monitoring device 1 of figures 5 and 6 to the inner surface 2 of the tyre, the dimensions, typically limited, of the rigid board (in particular the shorter length L of the rigid board with respect to the embodiment of figures 1 -4), ensure that substantially the whole monitoring device can be contained within the projection, onto the inner surface 2, of the maximum encumbrance of the central rib 91 of the tread 90. In this case, the single battery 40 can be arranged partially superimposed on the projection onto the inner surface of one of the two circumferential grooves 92, or within the projection onto the inner surface of the rib 91 .

Claims

1. Tyre (99) comprising a monitoring device (1 ), wherein said monitoring device (1 ) comprises an electronic unit (3) and an electric power supplier (4) electrically connected to each other, wherein said electronic unit (3) comprises at least one sensor (5) for detecting at least one of the following physical quantities: temperature, pressure, acceleration, deformation; a processing unit (6); a transceiver (7), wherein said monitoring device (1 ) comprises a rigid printed circuit board (8) comprising a first face (9) and a second face (10) mutually opposite, wherein the monitoring device (1 ) comprises at least one adhesive layer (20) proximal to said second face (10) for fixing said rigid board (8) to an inner surface (2) of said tyre (99) at a crown portion (93) of said tyre (99), and wherein said electronic unit (3) and said electric power supplier (4) are both fixed onto said first face (9) of said rigid board (8).

2. Tyre (99) according to claim 1 , wherein said rigid board (8) has elongated shape having a rectilinear main development direction (101 ), wherein said electric power supplier (4) is arranged at least in part at an end portion of said rigid board (8) with respect to said main development direction (101 ), and wherein a dimension of said rigid board (8) along said main development direction (101 ) is greater than or equal to 1 .5 times a dimension of the rigid board (8) along a direction perpendicular to said main development direction (101 ).

3. Tyre (99) according to any one of the previous claims, wherein said electric power supplier (4) is an electric energy accumulator comprising at least one battery (40), and wherein said electronic unit (3) comprises electronic components (5, 6, 7) at least in part spatially distributed onto a portion of said first face (9) of the rigid board left free by said electric power supplier (4).

4. Tyre (99) according to any one of the previous claims, wherein said electric power supplier (4) comprises one and only one battery (40), wherein a length (L) of the rigid board (8) along a main development direction (101 ) of the rigid board is greater than or equal to 35 mm, and less than or equal to 55 mm, and wherein a width (W) of the rigid board (8) along a direction perpendicular to the main development direction (101 ) is greater than or equal to 10 mm, and less than or equal to 25 mm.

5. Tyre (99) according to any one of the claims from 1 to 3, wherein said electric power supplier (4) comprises a pair of batteries (40) arranged mutually opposite to each other along a main development direction (101 ) of the rigid board (8), wherein a length (L) of the rigid board (8) along a main development direction (101 ) of the rigid board is greater than or equal to 50 mm and less than or equal to 80 mm, and wherein a width (W) of the rigid board (8) along a direction perpendicular to the main development direction (101 ) is greater than or equal to 10 mm, and less than or equal to 25 mm.

6. Tyre (99) according to any one of the previous claims, wherein said rigid board (8) has a thickness greater than or equal to 0.7 mm, and less than or equal to 3.0 mm, wherein said rigid board (8) comprises a laminated layer comprising one or more layers of a base material impregnated with a resin, wherein the laminated layer comprises one or more layers of glass fiber impregnated with an epoxy resin, wherein said rigid board (8) comprises a plurality of electric coupling regions arranged at said first face (9), wherein the electric coupling regions are connected to each other by a plurality of electrically conductive metal tracks, and wherein said metal tracks are partially arranged inside said laminated layer.

7. Tyre (99) according to any one of the previous claims, wherein said electric power supplier (4) is fixed to said first face (9) by gluing with a conductive glue interposed between a first pole (16) of said electric power supplier (4) and a first electric coupling region arranged onto said first face (9) of said rigid board (8), wherein said monitoring device (1 ) comprises a metal tab (15) which electrically connects a second pole (17) of said electric power supplier (4) to a second electric coupling region arranged onto said first face (9) of said rigid board (8), and wherein said metal tab (15) is connected to said second pole (17) and to said second electric coupling region by conductive glue.

8. Tyre (99) according to any one of the previous claims, wherein a top view surface extension of a first pole (16) of said electric power supplier (4) is greater than a top view surface extension of a second pole (17) of said electric power supplier (4).

9. Tyre (99) according to any one of the previous claims, wherein said monitoring device (1 ) comprises a protective layer which covers said electronic unit (3) and said electric power supplier (4) with continuity.

10. Tyre (99) according to claim 9, wherein said protective layer extends over a whole surface extension of said first face (9) of said rigid board (8), wherein said monitoring device (1 ) comprises a containment body (18) in single piece and made of polymeric material, wherein said containment body (18) at least partially realizes said protective layer, wherein said adhesive layer (20) is arranged in contact with a base surface (19) of said containment body (18), and wherein the base surface (19) of said containment body (18) has a top view contour substantially equal to a top view contour of said adhesive layer (20).

11. Tyre (99) according to claim 9 or 10, wherein said containment body (18) is open at said second face (10) of the rigid board (8), and wherein a base surface (19) of the containment body (18) is arranged flush with, and entirely surrounds, the second face (10).

12. Tyre (99) according to claim 9 or 10, wherein said containment body (18) entirely encapsulates said electronic unit (3), said electric power supplier (4) and said rigid board (8) with continuity.

13. Tyre (99) according to any one of the previous claims, wherein said adhesive layer (20) has a top view extension which exceeds a top view extension of the rigid board (8), preferably along a whole edge of the rigid board (8), wherein said adhesive layer (20) is in single piece, wherein said adhesive layer (20) comprises a decoupling element, said decoupling element preferably being a double-sided adhesive tape comprising (i) a viscoelastic acrylic foam, or (ii) a substrate of expanded polymeric material, or (iii) at least one layer of acrylic adhesive, or even a combination of a viscoelastic acrylic foam, a substrate of expanded polymeric material and at least one layer of acrylic adhesive, and wherein said adhesive layer (20) has thickness greater or equal to 0.5 mm, and less than or equal to 2.5 mm.

14. Tyre (99) according to any one of the previous claims, wherein said monitoring device (1 ) is fixed to the tyre so that an equatorial plane (100) of the tyre (99) crosses said rigid board (8), wherein a main development direction (101 ) of the rigid board (8) is substantially perpendicular to said equatorial plane (100), and wherein said monitoring device (1 ) is arranged onto said inner surface (2) of the tyre (99) so that said electronic unit (3) is substantially entirely contained in a projection, onto said inner surface (2), of an encumbrance of a central rib (91 ) of a tread (90) of said tyre (99).

15. Tyre (99) according to any one of the previous claims, wherein said electric power supplier (4) comprises at least one battery (40), and wherein said monitoring device (1 ) is arranged onto said inner surface (2) so that said at least one battery (40) is at least partially superimposed on a projection, onto said inner surface (2), of a groove