SYSTEM FOR MEASURING THE INTERNAL TEMPERATURE OF A RUNNING TIRE

Description

Technical field

[0001] The present invention relates to a system for measuring the temperature inside a rubber compound of a tire under real driving conditions. The tires mainly concerned equip civil engineering vehicles for mining operations.

[0002] For example, such vehicles (dumpers or dumpers) are used in open-pit mines to transport materials extracted from quarries with loads that can reach a mass of more than 350 tonnes. The tires are sized accordingly, and can each weigh around 5 tonnes.

[0003] For illustration purposes, a tire covered by the invention has a standardized designation according to ETRTO (European Tire and Rim Technical Organization) of type 59 / 80 R 63, with an inflation pressure of 650 kPa. The outer diameter of the tire mounted on a rim and inflated to 650 kPa can measure more than 4 meters. Other dimensions of 49 to 57 inches in diameter are also found on these vehicles. Definitions

[0004] By convention, a reference (O, t, y, r), whose center O coincides with the center of the tire, the circumferential (O, t), axial (O, y), and radial (O, r) directions respectively designate a direction tangent to the rolling surface of the tire according to the direction of rotation, a direction parallel to the axis of rotation of the tire, and a direction orthogonal to the axis of rotation of the tire.

[0005] By radially inner, respectively radially outer, we mean closer, respectively further from the axis of rotation of the tire.

[0006] Axially inner, respectively axially outer, means closer, respectively further from the equatorial plane of the tire, the equatorial plane of the tire being the plane passing through the middle of the tire tread and perpendicular to the axis of rotation of the tire.

[0007] By elastomeric mixture, or rubber mixture, we mean an elastomeric material obtained by mixing its various constituents. An elastomeric mixture conventionally comprises an elastomeric matrix with at least one diene elastomer of natural or synthetic rubber type, at least one reinforcing filler of carbon black type and / or silica type, a crosslinking system most often based on sulfur, and protective agents.

[0008] An elastomeric mixture can be characterized mechanically, in particular after curing, by its dynamic properties, such as a dynamic shear modulus G*= (G' 2< +G" 2< ) 1 / 2< , where G' is the elastic shear modulus and G" the viscous shear modulus, and a dynamic loss tgδ=G" / G'. The dynamic shear modulus G* and the dynamic loss tgδ are measured on a Metravib VA4000 type viscoanalyzer, according to the ASTM D 5992-96 standard. The response of a sample of vulcanized elastomeric mixture, in the form of a cylindrical specimen 4 mm thick and 400 mm 2< in cross-section, subjected to a sinusoidal stress in alternating simple shear, at a frequency of 10 Hz, with a strain amplitude sweep of 0.1% is recorded. at 50% (forward cycle), then from 50% to 0.1% (return cycle), and at a given temperature, for example equal to 60°C.These dynamic properties are thus measured for a frequency equal to 10 Hz, a deformation equal to 50% of the peak-peak deformation amplitude and a temperature which can be equal to 60°C or 100°C.

[0009] An elastomeric compound can also be characterized by static mechanical properties. Tensile tests are used to determine yield stresses and properties at break. Unless otherwise indicated, they are carried out in accordance with French standard NFT 46-002 of September 1988. In second elongation (i.e. after an accommodation cycle), the so-called "nominal" secant moduli (or apparent stresses, in MPa) are measured at 10% elongation (noted "MA10") and 100% elongation ("MA100"). All these tensile measurements are carried out under standard temperature (23±2°C) and hygrometry (50±5% relative humidity) conditions, according to French standard NF T 40-101 (December 1979). Stresses at break (in MPa) and elongations at break (in %) are also measured at a temperature of 23°C. Prior art

[0010] Generally speaking, a tire comprises a tread, intended to come into contact with the ground via a rolling surface, the two axial ends of which are connected via two sidewalls with two beads ensuring the mechanical connection between the tire and the rim on which it is intended to be mounted.

[0011] A radial tire further comprises a reinforcing reinforcement, consisting of a crown reinforcement, radially inside the tread, and a carcass reinforcement, radially inside the crown reinforcement.

[0012] The carcass reinforcement of a radial tire for a heavy vehicle of the civil engineering type usually comprises at least one carcass layer comprising generally metallic reinforcements, coated with a rubber mixture, obtained by mixing and called a coating mixture. A carcass layer comprises a main part, connecting the two beads together and generally wrapping, in each bead, from the inside to the outside of the tire around a circumferential reinforcement element, most often metallic, called a bead wire, to form a turn-up. The metallic reinforcements of a carcass layer are substantially parallel to each other and form, with the circumferential direction, an angle of between 85° and 95°.

[0013] The crown reinforcement of a radial tire for a heavy vehicle of the civil engineering type comprises a superposition of crown layers extending circumferentially, radially outside the carcass reinforcement. Each crown layer consists of reinforcements, generally metallic, parallel to each other and coated with a rubber mixture called a coating mixture.

[0014] Among the crown layers, a distinction is usually made between the protective layers, constituting the protective reinforcement and radially the outermost, and the working layers, constituting the working reinforcement and radially between the protective reinforcement and the carcass reinforcement.

[0015] The protective reinforcement, comprising at least one protective layer, essentially protects the working layers from mechanical or physicochemical attacks, likely to propagate through the tread radially towards the inside of the tire.

[0016] The protective reinforcement of GC type tires such as those described above usually comprises two protective layers, radially superimposed, formed of elastic metal reinforcements, parallel to each other in each layer and crossed from one layer to the next, forming, with the circumferential direction, angles at least equal to 10° and at most equal to 35°.

[0017] The working reinforcement, comprising at least two working layers, has the function of surrounding the tire and giving it rigidity and road holding. It absorbs both the mechanical stresses of inflation, generated by the tire's inflation pressure and transmitted by the carcass reinforcement, and the mechanical stresses of rolling, generated by the tire rolling on the ground and transmitted by the tread. It must also be resistant to oxidation and to impacts and perforations, thanks in particular to its intrinsic design and that of the protective reinforcement.

[0018] The working reinforcement usually comprises two working layers, radially superimposed, formed of non-extensible metal reinforcements, parallel to each other in each layer and crossed from one layer to the next, forming, with the circumferential direction, angles at most equal to 60°, and, preferably, at least equal to 15° and at most equal to 45°. Here, non-extensible metal reinforcements are understood to mean a metal reinforcement characterized by an elongation, under a tensile force equal to 10% of the breaking force at most equal to 0.2%.

[0019] To reduce the mechanical inflation stresses transmitted to the working reinforcement, it is known to arrange, radially outside the carcass reinforcement, a hoop reinforcement. The hoop reinforcement, the function of which is to absorb at least part of the mechanical inflation stresses, improves the endurance of the crown reinforcement by stiffening the crown reinforcement. The hoop reinforcement can be positioned radially inside the working reinforcement, between the two working layers of the working reinforcement, or radially outside the working reinforcement.

[0020] The hoop reinforcement usually comprises two layers of hoop, radially superimposed, formed of metal reinforcements, parallel to each other in each layer and crossed from one layer to the next, forming, with the circumferential direction, angles at most equal to 10°.

[0021] Mining is the extraction of ores, that is, rocks from the Earth's crust containing useful minerals or metals, in sufficient proportions to justify their exploitation.

[0022] The transportation stage of a mining operation is essential for its economic profitability. Vehicles (dumpers or dump trucks) are generally active non-stop in order to achieve maximum productivity by moving the largest volume of rubble to be processed by mineral processing.

[0023] Fleet tire management involves monitoring tire pressure, temperature, and wear using a predictive maintenance approach to anticipate tire-related malfunctions and thus avoid vehicle downtime to maximize its lifespan.

[0024] Thus, one of the expectations of the mining customer is the productivity of the operation, which must not be affected by product failures, and therefore the lifespan of the tires, which must be as long as possible. Vehicle downtime must be avoided and, consequently, preventive maintenance must be developed for controlled use of the tires.

[0025] Real-time tire temperature monitoring is an essential step in fleet management. Temperature is directly linked to tire endurance and lifespan.

[0026] It should be noted that documents US5731754A, US2017282657A1, US10836223B1, WO2004016454A1, US2005057346A1 propose solutions for accessing temperature measurement in tire compounds.

[0027] In document FR3060463, a method for estimating the severity of the conditions of use of a tire mounted on a vehicle is proposed. One step of this method evaluates the temperature inside a mixture, but this evaluation is based on a mathematical model which can be complex to implement in certain cases.

[0028] Application WO 2008046766A1 discloses a method for indicating the aging of a tire, in which a temperature is measured locally at least at one point of the tire. This method requires the installation of a temperature sensor directly in the tire, which can generate additional costs.

[0029] There is still a need to access the temperatures inside the rubber compounds of a rolling tire in a simple and non-destructive way. It is necessary to be able to locate the most thermally sensitive areas of the tire to measure the temperature in real time. To achieve this, driving conditions such as the nature of the ground, whether stony, muddy, or asphalt, the internal structure of the tire, or the topography of the mining site must be taken into consideration. Statement of the invention

[0030] The objective of the invention is to provide a system for measuring the temperature inside rubber compounds according to the conditions listed above.

[0031] The solution proposed by the invention consists of a system for measuring the temperature inside a rubber mixture of a rolling tire according to claim 1, comprising at least one sensor equipped with a microprocessor, radio transmission means, a temperature measuring probe, power supply means such as: the sensor is inserted into an area of the tire resulting from a manufacturing process, said area being identified according to predefined selection criteria; said sensor is buried in a hermetically sealed volume arranged inside a rubber mixture of the tire resulting from a manufacturing process; the system comprises means for holding the sensor in a fixed position while the tire is rolling.

[0032] A civil engineering tire includes a tread designed to be in contact with the ground. The nature of the ground varies depending on the conditions of use, sometimes muddy, stony, or even asphalt. To adapt to different types of ground, the tread has cutouts, particularly transverse or circumferential, so as to define blocks of rubber compound intended to ensure sufficient grip regardless of the nature of the ground to transmit the vehicle's torque. The blocks of rubber compound in the tread also have incisions to form softening sipes to promote grip on snowy ground, for example.

[0033] As mentioned above, the internal structure of these tires consists of several crown layers. Each crown layer includes reinforcements coated in rubber compounds. At the ends of these crown layers, the temperature is known to reach high levels due to the amplitude of deformations in these areas.

[0034] The criteria for selecting the sensor insertion area may include, for example, choosing rubber compound blocks from the tread, or the ends of the crown layers. Additional criteria may be defined based on driving conditions such as the nature of the soil, whether stony, muddy, or asphalt, the internal structure of the tire, or the topography of the mining site.

[0035] For the purposes of the invention, a tire resulting from a manufacturing process means that the invention relates to a tire already manufactured and that the insertion of the sensor does not interfere with the manufacturing process of the tire. The insertion of the sensors can be carried out before or after mounting the tire on the vehicle axle.

[0036] The sensor is buried in a hermetically sealed volume means that a location has been created for this purpose and then sealed hermetically after the sensor has been inserted.

[0037] One of the features of the invention is to directly access the temperature inside the selected rubber compound. The sensor equipped with radio transmission means is not connected to the outside, which allows the temperature of the tire to be measured while driving without stopping the vehicle. This measuring means does not affect the productivity of the mining operation, because the vehicle is not stopped to take the temperature measurements.

[0038] The radio transmission means include for each sensor an active transmitter which includes an electronic chip that stores the data and an antenna to operate in a given frequency band. The active transmitter communicates at regular time intervals the sensor identifier and the temperature value to a receiver located in the vehicle. The sensor's microprocessor averages the temperature over the time interval between two transmissions. Both the transmitter and the microprocessor consume the energy supplied by the power supply battery.

[0039] The transmission means are unidirectional and operate with low power consumption, mainly due to radio transmission. Such a design of the transmission means allows for miniaturization of the sensor and minimization of costs. It also provides good grip and durability despite the very demanding environment in which civil engineering machinery tires operate.

[0040] Another characteristic of the invention is that the holding means make it possible to keep the sensor in a fixed position without movement, without vibrations with the surrounding environment so as to obtain a measurement of satisfactory quality. These holding means are of different natures, such as for example chemical with adhesion glues or even mechanical with a clamping device linked to the dimensioning of the components of the device.

[0041] The measurements obtained with the sensor were compared with results of conventional temperature evaluation such as with thermocouples and confirmed both the quality and the precision of the values obtained with the invention.

[0042] Preferably, a layer of cold vulcanizing adhesive glue is placed between the outer surface of the sensor and the rubber mixture of the cavity.

[0043] Cold vulcanizing glue is a glue that causes a chemical reaction consisting of incorporating a vulcanizing agent, most often sulfur, into a raw elastomer to form bridges between the molecular chains. This operation makes the material less plastic but more elastic.

[0044] The inventors observed that the use of such an adhesive in the context of the invention allows for high-quality bonding between the sensor and the rubber mixture of the cavity.

[0045] A preferred example of adhesive glue is that produced by the company Tiptop, marketed under the name "blue cement" glue.

[0046] From a practical point of view, the outer surface of the tire is perforated to access the selected area and the desired position for installing the sensor. For example, the sensor can be positioned at the end of the protective crown layers where the radial thickness of the tire is at its maximum. After cleaning the perforated cavity, "blue cement" type glue is used to bond the sensor to the bottom and walls of the cavity. To do this, a thickness of glue of at least two millimeters is applied to the entire outer surface of the sensor. For the type of glue used, the setting time of the glue is at least twenty-four hours for this use.

[0047] The adhesive glue layer advantageously serves as a lubricant to facilitate the penetration of the sensor into the rubber compound layer of the tire.

[0048] Indeed, once the cavity is dug in the tire at the desired location, the sensor must be able to penetrate it so as to tighten it with the wall. To facilitate this penetration, the glue is chosen so as to ensure both the bonding and lubricating functions.

[0049] According to the invention, the sensor comprises at least part of the fixing means to keep it in a fixed position. The outer surface of the sensor is thus grooved to facilitate the fixing of the sensor in the rubber compound of the tire whose temperature is measured. Indeed, the grooves define asperities of the outer surface of the sensor to facilitate anchoring in the rubber compound.

[0050] In one embodiment, the sensor occupies a cylindrical volume whose cylinder length is less than or equal to the radial thickness of the tread measured in an equatorial plane of the tire. Advantageously, in an alternative embodiment, the sensor occupies a cylindrical volume whose cylinder length is less than or equal to 60 mm, and in which the cylinder diameter is less than or equal to 25 mm.

[0051] Preferably, the length of the cylinder is less than or equal to 45mm. The risks of damage to the cylinder, for example by bending, are minimized with such a length.

[0052] Preferably, the diameter of the cylinder is less than or equal to 17 mm.

[0053] In this embodiment, the cavity is advantageously dug using a drill equipped with a bit. The length and diameter of the cavity are defined at sufficiently low values in relation to the size of the tire so as to be able to reuse the tire without major repairs after extraction of the sensor.

[0054] A very advantageous particular case of this embodiment corresponds to the situation where the cylindrical geometry sensor is housed in a cylindrical cavity inside the rubber mixture, the diameter of said cylindrical cavity being less than or equal to that of the sensor.

[0055] The sensor penetration into the cavity is done with natural tightening when the sensor and the cavity have the same diameter.

[0056] When the temperature measurement must be carried out close to the crown layers, the depth of the cavity is significantly greater than the length of the sensor. Indeed, the radial thickness of the tread of the tires considered here is much greater than the length of the sensor. Thus, after fixing the sensor to the bottom and on the walls of the cavity, there remains an empty volume directed towards the outside of the tire which must be closed in order to protect the sensor. Preferably, the cavity containing the sensor is closed by a plug made of the same rubber compound as that containing the sensor.

[0057] The sensor, enclosed within a rubber compound, is subjected to periodic mechanical and thermal stresses due to the rotation of the tire. The sensor groups its constituent components, such as a thermocouple, a microprocessor, a radio transmitter, and a power battery, on an electronic card. In order to further preserve the integrity of this electronic card, advantageously, said electronic card is coated in an encapsulating resin.

[0058] The encapsulating resin is preferably epoxy-based to ensure the best protection of the electronic board. For additional mechanical protection, the sensor is also advantageously molded in a flexible material whose dynamic shear modulus is less than or equal to a quarter of the dynamic shear modulus of the mixture whose temperature is being measured. In this way, the deformations undergone by the portion of rubber mixture containing the sensor will mainly affect this layer of flexible protective material.

[0059] As previously stated, the sensor, which includes radio transmission means, operates remotely while the tire is in use. In an alternative embodiment of the invention, activation of the sensor consists of breaking a wire connecting two electrodes of the sensor. Activation of the sensor causes the temperature measurement operations to begin, and the temperature values and the sensor identifier to begin to be transmitted repeatedly.

[0060] In a variant embodiment of the invention, the tire contains an identification label.

[0061] According to this variant of this embodiment, the sensor is equipped with an active electronic module for measuring and transferring physical parameters of the tire, and said sensor comprises: i. means for measuring physical parameters other than the tire temperature; ii. means for reading the tire identification label; iii. a data transmission module for transmitting the physical data received from the sensor, including the tire identification, to a remote receiver;

[0062] In this embodiment, the sensor is provided with several means for measuring physical parameters, such as for example a piezoelectric measuring device, or a pressure detector. The tire and the sensor each have a passive identification tag. According to this embodiment, advantageously, it is provided that the passive identification tag of the tire can be an RFID tag independent of the sensor.

[0063] This embodiment of the invention allows management of tire tracking which consists of knowing reliably, at any time, their location, that of the tires and that of the sensor measuring the associated physical parameters. Description of Figures

[0064] The invention will be better understood upon reading the following description, given as a non-limiting example and with reference to the figures (1-A, 1-B, 2 , 3-A, 3-B ), in which: THE Figures 1-A, and 1-B represent views of the sensor of the temperature measurement system proposed by the invention. The figure 2 is a meridian plane (y,r) of the tire, that is to say a generating plane of the tire in three dimensions by the rotation of this meridian plane around the axis (O, y) of the cylindrical reference (O, t, y, r) associated with the tire. The Figures 3-A, and 3-Brepresent the curves of temperature measurement results obtained with means of the invention on a tested tire dimension. Detailed description

[0065] There Figure 1-A shows the sensor 10 which has a cylindrical shape geometry, a length LC and a diameter PHI, with the activation wire 12 which has a length LF. On the Figure 1-B , we can see a volumetric view of the sensor 10. The sensor 10 is intended to be inserted into the tire 20 of the figure 2 . Reference A of the Figure 1-A shows grooves which are a succession of hollows and bumps in the longest direction of the sensor, and said grooves are intended to facilitate the anchoring of the sensor in a rubber mixture of the tire 20.

[0066] The tire 20 is mounted on a vehicle equipped with a device for communication with said sensor.

[0067] The reading means positioned in the vehicle store the data in a database, accessible by a remote server. The sensor 10 comprises an electronic card with a circuit connecting the components such as a temperature measuring probe, a microprocessor, a radio transmitter, a transponder and a power supply battery.

[0068] When activating the sensor before inserting it into the rubber compound, the activation wire 12 is cut at its end in contact with the sensor.

[0069] On the figure 2, the tire 20 comprises a tread 201 represented by the volume comprising black dots radially the outermost of the tire. The crown reinforcement 210 is formed of a working reinforcement 211, a protective reinforcement 212 and a hooping reinforcement 213 radially superimposed externally. Each reinforcement comprises two layers formed of reinforcements coated in rubber compounds. Finally, the crown reinforcement comprises in this example six radially superimposed crown layers each formed of reinforcements coated in rubber compounds. Radially internal to the crown reinforcement 210 is the carcass reinforcement 220 which comprises at least one carcass layer formed of a forward strand 217 which goes around a bead wire 218 axially from the inside to the outside of the bead, and continues radially externally by a return strand 216.The reinforcements of the carcass layer make an angle of approximately 90° with the circumferential direction.

[0070] This architecture optimizes the tire's endurance to carry the required load, but has the disadvantage of being sensitive to temperature which catalyzes the phenomena of cracking and damage to the tire, particularly at the end of the crown layers.

[0071] Still on the figure 2, cavities 205 at the end of the crown layers and cavities 206 in the center of the tread, oriented from the outer periphery of the tire toward the inside of the rubber compounds are hollowed out to receive a temperature measuring sensor 10 respectively. The invention also works with cavities 207 positioned radially internally. The angle Alpha that the drilling direction makes with the radial direction as well as the depth HC of the cavity can be visualized. For cavities 205 and 206, the drilling direction is parallel to the radial direction and therefore the angle Alpha is zero. In this example, each sensor 10 has a length of 45 mm and a diameter of 17 mm so as to occupy a relatively small volume compared to the size of the tire. Indeed, at the end of the measurements, each sensor must be able to be extracted without damaging the tire.

[0072] The invention was implemented on a tire of dimension 59 / 80 R63 designated according to the ETRTO (European Tire and Rim Organization) standard which equips a dumper type vehicle. The tire tested is inflated to 650 kPa.

[0073] The front axle of the dumper was equipped with the above-mentioned tires. The front axle load is 63 tons.

[0074] The sensors were positioned to measure the temperature near the crown layers at the shoulders in cavities 205, and in the center of the tire in cavities 206. These areas were identified as being the most sensitive to temperature by numerical simulation taking into account the use of the tires and in particular the mine being operated. The test took place over 10 days.

[0075] The sensor includes an electronic board equipped with a temperature measuring probe and a radio transmitter, which can be interrogated by a reader positioned in the vehicle. The temperature probe, the radio transmitter, and the reader are standard references available commercially. The data transmission period from the sensor to the vehicle is five minutes.

[0076] On the Figure 3-A , we can see the comparison between the temperature measured by thermocouples (dashed curve, curve C2) and the temperature measured by means of the invention (continuous curve, curve C1). This result was obtained by adding thermocouples to a tire of the invention to carry out a comparative test with the same stress conditions on an appropriate machine.

[0077] There Figure 3-Bshows two curves B1 and B2 which reproduce the evolution of the temperature at the ends of the crown layers (curve B1 in solid lines) and at the center of the tread (curve B2 in broken lines) at a depth of at least 45 mm during the rolling of the tire. On the Figure 3-B , the x-axis represents the days of driving, and the y-axis represents the temperature.

[0078] The invention has the advantage of accessing the temperature level in rubber compounds in a simple and automatic manner, to the detriment of conventional approaches, for example, using thermocouples, which can have a negative impact on mining productivity. Indeed, vehicles are not stopped and human intervention is limited in the temperature measurement method proposed by the invention.

[0079] The measuring means of the invention give results consistent with those obtained with traditional means such as thermocouples. The measuring means, their method of insertion, the means of holding the sensors in a fixed position, as well as the means of communicating the measured temperature values are confirmed by these results.

[0080] A first example of application of the results of the invention is to adapt the conditions of use of the tires in real time according to the average temperature level. Warning devices can be put in place to warn the driver when the temperature reaches an excessive level, and to indicate to him that he must adapt his driving to preserve the tires.

[0081] A second example of using measurement results is to determine the temperature of the internal inflation air, for example from charts or numerical models, and thus to calculate the evolution of the inflation pressure during tire rolling. In this way, a performance compromise can be managed between wear and endurance, for example.

[0082] The principle of the invention can be extrapolated to other types of tires than those described here, in particular heavy goods vehicle type, and more generally to tires whose radial tread thickness is sufficient to implement the invention.

Claims

1. System for measuring the temperature inside a rubber compound of a tyre (20) when it is running, comprising at least one sensor (10) fitted with a microprocessor, radio transmission means, a temperature measuring probe and power supply means, the sensor being inserted in an area of the tyre originating from a manufacturing process, said area being identified depending on predefined selection criteria, said sensor (10) being embedded in a hermetically sealed volume formed inside a rubber compound of said area of the tyre originating from a manufacturing process, the outer surface of the sensor is grooved, the system comprising means for keeping the sensor in a fixed position while the tyre is running, characterized in that the sensor (10) is moulded from a flexible material of which the dynamic shear stiffness modulus is less than or equal to one quarter of the dynamic shear stiffness modulus of the compound of which the temperature is measured, the dynamic shear stiffness moduli being measured for a frequency equal to 10 Hz, a strain equal to 50% of the peak-to-peak strain amplitude, and a temperature equal to 60°C.

2. System for measuring the temperature inside a rubber compound of a tyre (20) when it is running according to Claim 1, wherein a layer of cold-vulcanized adhesive is laid between the outer surface of the sensor and the rubber compound of a cavity.

3. System for measuring the temperature inside a rubber compound of a tyre (20) when it is running according to Claim 2, wherein said layer of adhesive is a lubricant.

4. System for measuring the temperature inside a rubber compound of a tyre (20) when it is running according to one of the preceding claims, wherein the sensor (10) occupies a cylindrical volume of which the length of the cylinder is less than or equal to 60 mm, and wherein the diameter of the cylinder is less than or equal to 25 mm.

5. System for measuring the temperature inside a rubber compound of a tyre (20) when it is running according to the preceding claim, wherein the sensor of cylindrical geometry is received in a cylindrical cavity inside the rubber compound in said area of which the diameter of said cylindrical cavity is less than or equal to that of the sensor.

6. System for measuring the temperature inside a rubber compound of a tyre (20) when it is running according to one of the preceding claims, wherein the cavity containing the sensor (10) is closed by a stopper made of the same rubber compound as that containing the sensor (10).

7. System for measuring the temperature inside a rubber compound of a tyre (20) when it is running according to one of the preceding claims, wherein the sensor (10) comprises an electronic circuit board having a thermocouple, a microprocessor, a radio transmitter and a battery, said electronic circuit board being coated in an encapsulating resin.

8. System for measuring the temperature inside a rubber compound of a tyre (20) when it is running according to one of the preceding claims, characterized in that the sensor (10) comprises an activation wire connecting two electrodes of the sensor.

9. System for measuring the temperature inside a rubber compound of a tyre (20) when it is running according to one of the preceding claims, wherein the tyre (20) contains an identification tag.

10. System for measuring the temperature inside a rubber compound of a tyre (20) when it is running according to the preceding claim, wherein the sensor is fitted with an active electronic module for measuring and transferring physical parameters of the tyre, and said sensor has: i. means for measuring different physical parameters to the temperature of the tyre (20); ii. means for reading the tag of the tyre (20); iii. a data transmission module for transmitting the physical data received from the sensor (10) to a remote receiver.