manufacturing process and encapsulation device for electronic components of an electronic system for pneumatics

Abstract

The invention relates to an encapsulation component (120) of an electronic system (1) comprising: A rigid housing (300) comprising: A first and a second surface (311, 321) separated by a thickness E; Said rigid housing (300) includes a cylindrical through orifice (350); An elastic seal (150) inserted in the through orifice (350) of the rigid housing (300) and extending perpendicularly to the second surface (321) of the rigid housing (300) over a distance H3; Characterized in that the orifice (350) has a first (320) and a second shoulder (330), in that the orifice (350) extends from this second shoulder (330) over a height H2, in that the elastic seal (150) comprises a cylindrical orifice (151) coaxial with the axis of rotation (351) of the orifice (350), and in that the elastic seal (150) is in direct contact with the rigid housing (300) over the entire orifice (350). Fig. 2

Description

Title of the invention: Method for manufacturing and encapsulation device for electronic components of an electronic system for pneumatics Scope of the invention

[0001] The present invention relates to the field of electronic systems embedded on pneumatics having as their purpose the measurement of the parameters of the pressurized fluidic cavity of a mounted assembly delimited by at least one pneumatic and one wheel, and particularly the field of electronic systems positioned on the pneumatic. Technological background

[0002] In the transportation sector, vehicles are often required to monitor the inflation pressure of tire assemblies when these are pressurized by a fluid at a pressure higher than atmospheric pressure. This is to ensure proper tire performance and, consequently, vehicle performance, thereby guaranteeing the safety of vehicle passengers and other road users. Beyond simply issuing an alert in the event of a significant pressure loss that immobilizes the vehicle, it is also necessary to be able to detect incorrect inflation pressure due to the natural and continuous porosity of tires in order to optimize the operation of the tire assembly. This second function of electronic tire pressure monitoring systems requires increased precision in their measurement chain.However, electronic systems mounted on the wheel rim are often subjected to temperature fluctuations due to their proximity to potentially hot components such as brake discs, calipers, or drums. These thermal changes also affect the accuracy of measurements of the physical parameters of the fluidic cavity within the assembled system.

[0003] Furthermore, for vehicles carrying heavy loads, such as trucks or buses, the inflation pressures of the mounted assemblies are increased, to around 9 bar instead of the 2 to 3 bar inflation pressure for passenger vehicles. This increased pressure tends to exert thermomechanical stress on conventional electronic systems, sometimes causing mechanical deformation of the electronic systems at the level of their encapsulation system. This can lead to alterations in the measurement chain by modifying the measured pressure, for example, by changing the cross-section exposed to the fluidic cavity or by reducing the sealing of the electronic system subjecting the components. Electronic components are subjected to pressures that damage their operation. These mechanical deformations lead to a malfunction of the electronic system's measurement chain, resulting in a loss of measurement accuracy. Typically, the encapsulation of electronic components consists of a permanent, sealed assembly of two compartments. At least one of these compartments has an opening for communication with the external environment at the level of the sensors that measure the fluid's physical parameters. The sealing system of the encapsulation device consists of positioning a gasket, usually silicone, at the opening. The compression of the seal between the compartment containing the orifice and the measuring sensor, outside the sensor's active area, ensures the electronic system's watertightness. While solutions exist for mechanically resizing the encapsulation device or redesigning its sealing, these alternatives result in an increased cost of the electronic system and / or an increase in the mass of the electronic system mounted on the tire. These consequences make the use of such improved electronic systems economically unreliable in the field of pressurized tire transport, particularly for heavy goods vehicles.

[0004] The object of the following invention is to propose an economical technical solution for sealing the electronic system for pneumatics, allowing optimized operation of the electronic system, particularly when used in environments with high inflation pressure. Description of the invention

[0005] The invention relates to a method for manufacturing a sub-component of an encapsulation device for electronic elements of an electronic system for pneumatics, comprising the following steps: • During a first phase: Production of a rigid casing by heating and then injection of a thermoplastic into a first mold comprising at least two dies: • The first matrix comprising a first surface, defining a first surface SI of the rigid housing, presenting a first cylindrical element of diameter DI projecting along a first axis of revolution; • The second die, comprising a second surface defining a second surface S2 of the rigid housing, has a second protruding cylindrical element whose axis of revolution can be coaxial with the first axis of revolution when the first mold is closed, and whose diameter D2 is greater than the diameter DI of the first cylindrical element and the second cylindrical element extends axially over a height H2; • At least one of the two protruding elements extending axially in the form of a cylinder coaxial with the axis of revolution of the cylindrical element over a diameter D3 smaller than the two diameters DI and D2 of the cylindrical elements over a length greater than or equal to the distance between the first two cylindrical elements when the mold is closed, preferably the other protruding element having a cylindrical recess coaxial with the cylindrical element with a diameter adjusted to diameter D3; and • During a second phase: Production of a sub-component by injection via a nozzle and then cooling of a thermoelastic elastomer in a second mold suitable for housing the rigid casing, the second mold comprising at least two dies: • At least one third matrix comprising a third surface bearing on the first surface of the rigid housing and obstructing the cylindrical orifice of the rigid housing; • At least one fourth matrix comprising a fourth surface bearing on the second surface of the rigid housing, this second face having a non-through cylindrical orifice whose axis of revolution is coaxial with the axis of revolution of the cylindrical orifice of the rigid housing and whose diameter is greater than or equal to the diameter of the orifice of the rigid housing and extending along the axis of revolution (304) over a height H3; • At least one third die or at least one fourth die comprising a straight insert coaxial to the axis of rotation of the rigid housing orifice, extending at least to the bottom of the cylindrical orifice of the at least fourth die or at least to the first face of the fourth die; and The insert (502) is coated with a material that is chemically inert with respect to the thermoelastic elastomer.

[0006] Such a process makes it possible to produce a rigid housing that can withstand the stresses exerted by the inflation pressure without deforming excessively, thus guaranteeing the housing's geometry when it contributes to the encapsulation device. The sealing of the electronic system will therefore be ensured.

[0007] This rigid housing has an orifice passing through it, which will establish fluidic communication between the two physical media separated by the rigid housing. This orifice has a shoulder system. The shoulder has a radial thickness El, The shoulder, corresponding to the difference between diameters DI and D3, ensures mechanical anchoring of the elastic sub-component to the rigid housing during the forces generated by the inflation pressure on the electronic system. The force absorbed by the shoulder then limits the elastic deformation of the sub-component. This ensures, for example, that the fluid passage of the elastic sub-component is not reduced, thus guaranteeing improved measurement accuracy at the sensor level for the fluid's physical parameters within the electronic system. The second shoulder of the orifice, with a radial thickness E2, corresponding to the greater difference between diameters D2 and D3 compared to the first radial thickness E1, ensures mechanical anchoring of the elastic sub-component to the rigid housing during compression of the elastic sub-component during the assembly of the encapsulation device.Indeed, the assembly of the encapsulation device reduces the distance between the free edge of the elastic subcomponent and the S2 surface of the rigid housing by compressing the elastic subcomponent onto the measuring sensor located within the electronic system. This compression ensures the fluidic sealing of the electronic system. To ensure that this compression is axial at the level of the elastic subcomponent, it is guided by the orifice of the rigid housing over a thickness H2. The cylindrical shape of the orifice of the rigid housing, as well as that of the elastic subcomponent, ensures a homogeneous radial deformation of the elastic subcomponent. This guarantees a cross-section of the fluidic channel of the elastic subcomponent without any unanticipated reduction in its dimensions, thereby improving the measurement accuracy of the sensor.Furthermore, the thickness H2 of the cylindrical orifice in the rigid housing and the mechanical anchoring of this sub-component within the rigid housing also ensure the positioning of the elastic sub-component relative to the geometry of the rigid housing. Thus, despite the geometric variations in the design of the rigid housing, the encapsulation device, and the positioning of the electronic components within the encapsulation device, the sealing function is ensured by the elastic sub-component by better controlling its geometric positioning and dimensions. For this to be achieved, the elastic sub-component, and in particular the internal fluidic channel passing through it, must be geometrically positioned relative to the measurement sensor of the electronic system.Furthermore, the compression ratio of the elastic subcomponent at the cylinder between the free end and the surface of the second shoulder of the rigid housing—that is, the cylinder over the height corresponding to the sum of heights H2 and H3—must be at least twenty percent and less than forty percent of this height. Finally, in order to create a controlled through-hole geometry for the elastic subcomponent with a surface finish that is not excessively rough, the insert in contact with the thermoelastic elastomer is straight and has an outer coating that will not create [a specific characteristic]. adhesion with the thermoelastic elastomer. This ensures that the extraction of the second mold during the production of the elastic sub-component will not generate deformation of the thermoelastic elastomer in contact with the insert, which ensures an adequate and homogeneous surface condition and increased demolding of the sub-component of the encapsulation device consisting of the assembly of the rigid housing equipped with the elastic sub-component.

[0008] The proposed two-phase process, whether carried out on two mold stations or on a single station with a so-called slide-type mold for modifying the dies, actually requires little precision. Indeed, unlike a conventional process where a prefabricated elastic sub-component is positioned on a rigid housing, here the manufacturing of the elastic sub-component is performed directly on the rigid housing. This eliminates the step of positioning the elastic sub-component relative to the rigid housing, and the step of securing the elastic sub-component to the rigid housing. Consequently, the variation in tolerances is reduced, which allows for improved miniaturization of the electronic system elements. Thus, the electronic system is ultimately more compact with an improved scrap rate, which reduces its production cost for the same sealing function.

[0009] Preferably, the outer diameter of the insert is less than one-third of the diameter D3; preferably, the insert is cylindrical in shape

[0010] The insert is straight, and the orifice created by the insert in the elastic sub-component follows the general external shape of the insert. By dimensioning the external diameter of the insert, the diameter of the orifice passing through the elastic sub-component is thus dimensioned. The external diameter D3 of the elastic sub-component at the constriction of the elastic sub-component is radially constrained by the rigid housing. If the external diameter of the insert is less than one-third of the external diameter D3 of the constriction, the elastic sub-component is formed in which the smallest part, the constriction, has a cross-section at least proportional to two-thirds of the diameter D3. Furthermore, the cylindrical shape of the orifice ensures a homogeneous radial distribution of stresses on the orifice, which ensures homogeneous and minimal deformation of the orifice of the elastic sub-component.

[0011] Preferably, the radial thickness El of the first element, corresponding to the difference between the diameter DI and the diameter D3, is greater than 0.2 millimeters, preferably the thickness El is greater than or equal to 0.3 millimeters.

[0012] The contact area between the rigid housing and the elastic sub-component under axial stress generated by the pressure of the fluidic cavity of the assembled unit is dimensioned by this quantity. Such a thickness El ensures that the rigid housing will have reasonable deformation under an inflation pressure of 10 bar and that, moreover, it will not be subject to the onset of crack propagation up to a Inflation pressure of 12 bars.

[0013] Advantageously, the radial thickness E2 of the second element, corresponding to the difference between the diameter D2 and the diameter D3, is greater than 0.5 millimeters, preferably the thickness E2 is greater than or equal to 0.85 millimeters.

[0014] The contact area between the rigid housing and the elastic sub-component under axial stress generated by the compression of the elastic sub-component is dimensioned by this quantity. Such a thickness E2 ensures that the rigid housing will have a reasonable deformation for a compression of the elastic sub-component of approximately 50% and that, moreover, it will not be subject to crack initiation at the contact surface of the rigid housing.

[0015] In a particular embodiment, the axial height H2 of the second element is greater than 0.5 millimeters, preferably greater than or equal to 0.8 millimeters.

[0016] The purpose of the axial height H2 is to define the anchoring height of the elastic sub-component within the rigid housing. This anchoring is useful during the compression phase of the elastic sub-component during the assembly of the electronic system, i.e., the final closure of the encapsulation device. In cases where, due to manufacturing variations in the various elements of the electronic system, the compression of the elastic sub-component results in a non-axial tilt, this anchoring height compensates for part of the tilt defect, thus ensuring a minimum level of sealing functionality for the electronic system and proper operation of the measurement of the fluid's physical parameters communicated with the measuring sensor through the opening of the elastic sub-component.In particular, despite the lack of inclination during compression, the stresses are distributed over the entire rigid casing so that it retains sufficient mechanical endurance under pneumatic conditions.

[0017] Preferably, the axial height H3 of the non-through orifice of at least a fourth die is between 0.8 and 1.3 millimeters.

[0018] The elastic sub-component is intended to undergo, as a first stress during its use in an electronic system, an axial compression generated by the reduction of the distance between the two components of the encapsulation device.

[0019] The area of ​​the elastic sub-component with height H3 resulting from the second phase of the process is not radially constrained, unlike the area of ​​the elastic sub-component with axial height H2. In fact, this area with height H2 is constrained by the rigid housing. Consequently, the area with height H3 will experience the highest compression ratio of the elastic sub-component during the assembly of the electronic system, which will conclude with the final closure of the encapsulation device. Height H3 therefore controls both the closure of the encapsulation device, its spatial dimensions, and its sealing through the compression ratio of the elastic sub-component. The proposed height range meets these three constraints by taking into account the dispersion of the elements in the chain of ribs.

[0020] The invention also relates to a sub-component of an encapsulation device for the electronic elements of an electronic system for pneumatics, comprising: • A rigid housing comprising: • A first surface and a second surface separated by a thickness E of material; • Said rigid housing includes at least one cylindrical through-hole about an axis of revolution from the first surface to the second surface; • A cylindrical elastic joint around an axis of revolution, inserted in the through orifice of the rigid housing and extending perpendicularly away from the second surface of the rigid housing over a distance H3; • Characterized in that the orifice of the rigid housing has a first shoulder from the first surface SI over a radial thickness El, in that the orifice of the rigid housing has a second shoulder from the second surface S2 over a radial thickness E2, in that the orifice extends outwards from this second shoulder over a height H2, in that the elastic seal comprises a cylindrical orifice coaxial with the axis of revolution and coaxial with the axis of rotation of the through orifice of the rigid housing and in that the elastic seal is in direct contact with the rigid housing over the entire through orifice of the rigid housing.

[0021] Preferably, the rigid housing being made of polyamide, the elastic seal is made of a thermoelastic elastomer included in the group comprising thermoplastic elastomers, vulcanized thermoplastic elastomers.

[0022] While mechanical anchoring does not necessarily require adhesion between the rigid housing and the elastic sub-component, it is preferable to reinforce this anchoring through chemical compatibility between the materials of the two components. This allows for the creation of chemical bonds that will generate cohesive forces, limiting movement between the two components. Polyamide, with its good geometric stability and high-temperature performance, is an ideal candidate for molding the rigid housing. The elastic seal material must have a certain level of chemical affinity with the polyamide to guarantee adhesion performance between the two structural components. The proposed lists are materials exhibiting this level of chemical affinity with polyamide.

[0023] Advantageously, the opening of the elastic seal is cylindrical in shape and with a diameter between 0.8 millimeters and 1.5 millimeters, preferably between 1 millimeter and 1.3 millimeters.

[0024] By default, the elastic seal is cylindrical. It is preferable for the opening of this seal to also be cylindrical in order to maintain an axisymmetric structure of the elastic seal. This will not create any mechanical singularities at the seal, and especially at the opening. This axisymmetry of the opening ensures a continuous cross-section of the opening, which does not disturb either the pressure within the opening or the thermomechanical stresses of the elastic seal during its use. Adhering to the diameter range ensures an accurate measurement of the external pressure relative to that of the opening, while maintaining a useful cross-section for the fluid greater than the boundary layer applied to the internal surface of the opening. This allows for precise measurement of the physical parameters of the fluid coming from the external environment and passing through the opening.

[0025] The invention also relates to an electronic pneumatic system comprising: • An encapsulation device comprising • A sub-component according to the object of the first invention; • A second rigid housing impermeably bonded to the sub-component on a closed contour; • Electronic components contained within the encapsulation device including at least one sensor for measuring a physical parameter of a fluid. The electronic system is characterized in that at least one measuring sensor is in contact with the elastic seal of the subcomponent arranged so that the active part of at least one measuring sensor is in fluidic communication with a medium external to the electronic system through the orifice of the elastic seal.

[0026] Such an electronic system is impermeable to impurities present in the external fluid due to the seal between the sub-component and the second rigid housing, and the presence of the elastic seal at the sub-component. Thus, the impurity-sensitive components of the electronic system are protected from impurities by the encapsulation device. In particular, electronic components such as the microcontroller, the battery, and the printed circuit board connectors are protected from water, especially in the event of condensation due to cooling after tire use, for example.

[0027] The invention also relates to a tire comprising an electronic system in which the tire, having an axis of rotation, is delimited by an external surface located radially external to the tire with respect to the axis of rotation and an internal surface located radially internal to the tire, and comprises a crown adapted to be in contact with the ground, two sidewalls located on either side of the crown and two ridges located at the other end of each sidewall Suitable for contact with a wheel rim, the electronic system is fixed to the inner surface of the tire, preferably at the top, arranged so that the opening of the elastic seal is free.

[0028] This is the case where the electronic system is installed on the tire in order to measure the physical parameters of the fluid trapped in the fluidic cavity formed by the tire when it is mounted on a wheel to form a complete assembly. Before forming a complete assembly, the tire, after manufacturing, may be stored in a warehouse where the aerological conditions are not those of a room used for tertiary-type human activity. Consequently, impurities, and in particular liquid water or other fluids, may come into contact with the tire during this storage or handling. The sealing provided by the encapsulation device, and in particular the elastic seal, preserves the proper functioning and prevents damage to the electronic components of the electronic system, even in the absence of pressurization of the fluid in the fluidic cavity of the complete assembly.Indeed, the seal is ensured by the closure of the encapsulation device which compresses the elastic seal appropriately.

[0029] Preferably, the attachment to the internal surface of the electronic system is achieved by means of a fastening device comprising a base whose external surface is in contact with the tire and whose internal surface forms with at least one lateral retaining wall a cavity suitable for receiving the electronic system.

[0030] This is a particular embodiment in which the electronic system is attached to the inner wall of the tire by a specific part. This specific part, the fastening device, is generally made of an elastomer compatible with fastening techniques commonly used in the tire industry for attaching elastomeric components together, even if they are chemically incompatible. Furthermore, this fastening device, being elastic, tends to dampen the levels of displacement and / or stress experienced by the electronic system during the use of the assembled unit. Moreover, the attachment of the electronic system to the fastening device is not permanent, allowing the electronic system to be replaced in case of failure, such as a battery discharge.Therefore, the electronic system is secured within the mounting device by mechanical anchoring through the creation of a cavity designed to accommodate the electronic system. This mechanical anchoring involves the elastic retention of the electronic system through stress deformation of the cavity wall, which allows for an elastic modification of the cavity's volume. Necessarily, the free end of the hollow orifice of the encapsulating device's elastic seal must open into the cavity opening of the mounting device. during the insertion or extraction of the electronic system from the fastening device.

[0031] Finally, the invention also relates to an assembly comprising a tire having an axis of rotation, being delimited by an external surface radially external to the tire with respect to the axis of rotation and an internal surface located radially internal to the tire, and comprising a top adapted to be in contact with the ground, two sidewalls located on either side of the top and two beads located at the other end of each sidewall, and a wheel, the wheel comprising an axisymmetric rim around the axis of rotation of the tire and a wheel disc, the internal surface of the tire and the external surface of the rim delimit a fluidic cavity of the assembly in fluidic communication with the electronic system, arranged so that the orifice of the elastic seal opens into the fluidic cavity.

[0032] This is the purpose of the final destination of the electronic system comprising an encapsulation device made watertight by the presence of a hollow seal inserted in the sub-component of the encapsulation device. The compression of the seal, guided by its insertion in the sub-component, during the final and watertight closure of the encapsulation device onto a closed contour, due to the positioning of the sub-component on the rigid housing, ensures the watertightness of the encapsulation device compartment. It is only necessary to ensure that the hollow opens directly onto the fluidic cavity whose physical parameters are to be measured.

[0033] According to a first embodiment, the electronic system is fixed on the wheel, preferably on the wheel rim.

[0034] According to another embodiment, the electronic system is fixed on the inner surface of the tire, preferably at the top.

[0035] These are two locations on the assembly where mounting the electronic system is easily feasible. On the wheel, and in particular the wheel rim, the mass of the electronic system is small compared to the wheel. Taking into account this mass, which may be off-center relative to the wheel's natural axis of rotation, does not significantly alter the behavior of the assembly. This is a perfect position for measuring the physical parameters of the fluidic cavity of the assembly under steady-state conditions. On the tire, and specifically opposite the crown, it is ideally located for measuring tire deformations during rolling. Indeed, the electronic system is then able to measure the periodic deformation, that is, per wheel rotation, of the tire at the point of contact with the ground. Here too, the mass of the electronic system is small compared to that of the crown, which does not alter the mechanical behavior of the tire.Brief description of the drawings.

[0036] The invention will be better understood upon reading the following description given solely as a non-limiting example and made with reference to the attached figures in which the same reference numbers designate identical parts throughout and in which: • Fig. 1 presents a cross-sectional view of the first mold for manufacturing the rigid housing according to the invention; • Fig. 2 presents a cross-sectional view of the second mold for manufacturing the elastic seal of the sub-component of the encapsulation device according to the invention; • Fig. 3 presents a cross-sectional view of the sub-component in a median plane of the elastic joint according to the invention; • Fig. 4 presents a cross-sectional view of the electronic system in a median plane of the elastic joint according to the invention; • Fig. 5 is a three-dimensional view of a tire equipped with an electronic system according to the invention; Detailed description of the implementation methods

[0037] Fig. 1 illustrates the first phase of the process of making the sub-component of the electronic component encapsulation device according to a preferred embodiment, i.e. making the rigid housing with a specific arrangement of the mold dies.

[0038] The dies 601 and 602 of the first mold 600 are shown here in cross-section during the closing of the mold. As a result, the dies 601 and 602 are in contact.

[0039] The die 601 has a first surface 611 defining the external surface of the rigid housing. On this surface 611 appears a first cylindrical element 612 of diameter DI projecting about an axis of revolution 614. This cylindrical element will form the first shoulder of the rigid housing. In this particular case, this first cylindrical element 612 extends axially by means of a cylindrical extension 632 about the same axis of revolution 614 over a smaller diameter D3. This element of the die defines the constriction of the opening of the rigid housing.

[0040] The second die 602 comprises a second surface 621 defining the internal surface of the rigid housing. This second surface 621 has, on the one hand, a second cylindrical element 622 about an axis of revolution 624, of diameter D2 about an axis of revolution 624. The diameter D2 is larger than the diameter DI due to the greater stresses that the housing will undergo during the assembly of the electronic system compared to the stresses it will undergo in use on a pneumatic system, for example. This second cylindrical element 622 extends over a height H2 in order to define a radial support for the elastic sub-component that will be manufactured after the rigid housing has been produced. On the other hand, this second cylindrical element 622 has a non-through cylindrical orifice 642 about the same axis of revolution 624. A diameter D3 is adjusted so that, when the mold 600 is closed, the cylindrical extension 632 of the first cylindrical element 612 can easily fit into this cylindrical orifice 642. The combination of the extension 632 and the orifice 642 ensures coaxiality of the dies at the protruding elements, which is preferable for defining an axisymmetric geometry of the orifice in the rigid housing that will accommodate the elastic seal of the sub-component of the encapsulation device. Naturally, for the demolding of the rigid housing, the elements, and in particular the cylindrical elements, have suitable draft angles. Of course, although not shown in this figure, at least one orifice passing through at least one die allows the injection of the thermoplastic into the closed mold to produce the part.

[0041] Fig. 2 illustrates the second phase of the process of making the sub-component of the electronic component encapsulation device according to one embodiment, i.e. making the elastic sub-component at the orifice of the rigid housing 300.

[0042] The dies 401 and 402 of the second mold 400 are shown in cross-section during the closing of the second mold. As a result, the dies 401 and 402 are in contact. This second mold may be different from the one used in the first phase. It may also be the same mold, but with a so-called "drawer" mold that allows for local modification of certain part geometries depending on the phase of the process. At this point, no manipulation of the rigid housing 300 is performed between the first and second phases of the process.

[0043] The die 401 has a third surface 411 bearing against the outer surface of the rigid housing 300. This surface 411 obstructs the cylindrical orifice 301 around the axis 304 passing through the rigid housing 300. Here, this die 401 includes an orifice 501 extending from the outside of the die to the third surface 411 and opening at the orifice 301 of the rigid housing 300 to fill the mold space, thus enabling the production of the elastic sub-component

[0044] The die 402 includes a fourth surface 421 bearing against the inner surface of the rigid housing 300. This die 402 has, on the one hand, a second cylindrical element 422, hollowed out from the fourth surface 421 around an axis of revolution 424, with a diameter D2 here, although it could have been different. The diameter D2 is larger than the diameter DI because of the greater stresses that the housing will undergo during the construction of the electronic system compared to the stresses it will undergo in use on a pneumatic system, for example. This cylindrical hollow 422 extends over a height H3 to define a compression height and a contact between the elastic sub-component to be manufactured and the sensor for measuring the physical parameters of the electronic system. On the other hand, this second cylindrical element 422 has a The insert, here cylindrical 502, is centered around the same axis of revolution 424 and extends axially over a length at least equal to the distance between the bottom e of the cylindrical cavity 422 and the surface 411 of the third die 401 when the mold is closed. Ideally, the third surface 411 of the die 401 has a cylindrical orifice with a diameter matched to that of the element 502, centered on the axis of revolution 304 of the orifice 301 of the rigid housing 300, to allow the element 502 to penetrate this orifice when the mold 400 is closed. This ensures the coaxiality of the insert 502 with the axis of revolution 304 of the opening 301 of the rigid housing 300. This insert 501 has a surface coating that is chemically inert with the thermoelastic elastomer injected into this second mold.This allows, among other things, easy demolding of the elastic sub-component at the level of this insert 501 and ensures a suitable surface finish of the through orifice of the elastic sub-component generated by this insert 501 at the end of the manufacturing process.

[0045] Of course, for the demolding of the sub-component of the encapsulation device, the elements, and in particular the cylindrical elements, have suitable draft angles.

[0046] Fig. 3 presents a cross-sectional view of subcomponent 120 of an encapsulation device of an electronic system.

[0047] This subcomponent 120 may preferably have been manufactured using the process described above. It consists of two elements: a rigid housing 300 and an elastic seal 150.

[0048] The rigid housing 300 has a first surface 311 which will be oriented externally to the electronic elements in the encapsulation device and a second surface 321 oriented internally.

[0049] The surface 321 shall have a continuous shoulder located laterally outside the surface 321 which shall serve to link the subcomponent 120 with the other elements of the encapsulation device to constitute a closed and sealed contour by linking this shoulder with the other elements of the encapsulation device.

[0050] This rigid housing 300 has a cylindrical through orifice 350 about an axis of revolution 351. This cylindrical orifice 350 has a first shoulder 320 extending from the surface 311 over a radial thickness EL. The orifice 350 has a second shoulder 330 extending from the surface 321 over a radial thickness E2 greater than EL. In addition, this second shoulder extends axially over a height H2 towards the surface 321. This height H2 ensures positioning of the elastic seal in the housing and axial guidance of the latter during compression of the elastic seal during the closure of the encapsulation device.

[0051] In this orifice 350 is housed an elastic seal 150 of cylindrical shape around an axis of revolution 154 coaxial with the axis of revolution 354 of the through orifice 150. The cylindrical seal 150 is in direct contact with the rigid housing 300 across the entire length of the through-hole 350. The shoulders 320 and 330 of the hole 350 provide mechanical anchoring of the seal 150 within the rigid housing 300. Furthermore, by manipulating the material properties of the rigid housing 300, and in particular the surface coating of the through-hole 350 and the elastic seal 150, chemical bonds can be created between the two components. This strengthens the rigidity of the elastic seal's placement within the rigid housing, preventing, for example, rotation of the rigid housing relative to the elastic seal. This elastic seal 150 extends axially inward toward the encapsulation device over a length H3 to make contact with the electronic components of the electronic system, and in particular the sensor for measuring the fluid's physical parameters.This height H3 is also dimensioned so that the elastic seal 150 is axially compressed during the assembly of the electronic system in order for this seal to perform its sealing function. A compression of at least 20 percent of the length H3 is necessary for this sealing function for an electronic system for pneumatics.

[0052] Finally, this seal 150 has an orifice 151 centered on the axis of revolution 154 in order to connect the two media initially separated by the encapsulation device. This orifice 151 is generally cylindrical around the axis of revolution 154, here with a diameter on the order of a millimeter, in order to maintain the axisymmetry of the elastic seal, which will ensure a homogeneous distribution of stresses and strains at the elastic seal 150. In addition, the internal surface of this orifice 150 has a suitable roughness so that the boundary layer acting on the internal surface of the orifice 151 is negligible compared to the effective cross-section of the orifice 151, thus improving the measurement accuracy of the physical parameters of the fluid flowing through this orifice 151. Finally, the orifice 151 is dimensioned so that its diameter is less than one-third of the diameter of the constriction zone of the elastic seal 150.This constriction zone is created by the two shoulders 320 and 330 of the rigid housing 300. It corresponds to the minimum material area that can withstand the highest stresses during the service operation of the elastic seal. The size of the orifice 151 ensures a sufficient quantity of material at the constriction for the elastic seal 150 to have adequate mechanical endurance during its use in an electronic or pneumatic system.

[0053] Fig. 4 shows a cross-section of an electronic system 1 for pneumatics.

[0054] This electronic system 1 is composed here of an encapsulation device comprising a sub-component 120 and a rigid housing 101, and electronic elements constituting the electronic board, the latter comprising a printed circuit 5 on which are positioned a fluid physical parameter measurement sensor 2, a microprocessor 3 and a battery 4.

[0055] The electronic components are located inside the encapsulation device, having been previously positioned on the rigid housing 101 by means of a system of ribs in the rigid housing 101. If the microprocessor 3 and the measuring sensor 2 are soldered to the printed circuit board 5 using conventional state-of-the-art techniques, a battery is attached to the printed circuit board by a system of conductive arms soldered to the printed circuit board. These arms clamp the battery to form the battery 4.

[0056] Subcomponent 120 corresponds to that described in [Fig. 3]. It therefore comprises a rigid housing 300 and an elastic seal 150. This subcomponent 120 is arranged relative to the rigid housing 101, which previously housed the electronic board, such that the free surface of the elastic seal 150 is aligned with the active part of the measuring sensor 2 on the electronic board. Then, a compressive force is applied axially to subcomponent 120 in the direction of the rigid housing 101. This force compresses the elastic seal, which has the lowest rigidity of the assembly, to ensure a compression of at least 20% of the radial free height of the seal 150. This compression ratio ensures a seal of the seal with respect to the measuring sensor 2 and therefore of the entire electronic board with respect to the through-hole of the elastic seal 150.

[0057] Finally, a continuous weld 160 is made around the entire periphery of the encapsulation device, maintaining the compressive force between the subcomponent 120 and the rigid housing 101 at the contour delimited by the shoulder laterally external to the rigid housing 300. This weld 160 also ensures the sealing of the electronic system 1 against the external environment. Furthermore, it ensures the tamper-proof nature of the electronic components contained within the electronic system 1. Only the destruction of the weld 160 and, consequently, of the encapsulation device, allows the extraction of the electronic components.

[0058] Figure 5 shows a cross-section of a tire 100 according to the invention, comprising a top S extended by two sidewalls F and terminating in two bead ridges B. In this case, the tire 100 is intended to be mounted on a wheel, which is not shown in this figure, at the level of the two bead ridges B. This defines a closed cavity, containing at least one pressurized fluid, delimited both by the radially inner surface 130 of the tire 100 and by the outer surface of the wheel. The tire 100 also includes a surface 140 radially external to the tire 100.

[0059] The reference axis 201, corresponding to the reference axis or natural axis of rotation of the tire 100, and the median plane 211, perpendicular to the reference axis 201 and equidistant from the two bead ridges B, shall be denoted. The intersection of the reference axis 201 by the median plane 211 determines the center of the tire 200. A Cartesian coordinate system will be defined at the center of the tire 200, consisting of the reference axis 201, of a vertical axis 203 perpendicular to the ground and a longitudinal axis 202 perpendicular to the other two axes. And, we will define the axial plane 212 passing through the reference axis 201 and the longitudinal axis 202, parallel to the ground plane and perpendicular to the median plane 211. Finally, we will call the vertical plane 213 the plane perpendicular to both the median plane 211 and the axial plane 212 passing through the vertical axis 203.

[0060] Every material point of the tire 100 is uniquely defined by its cylindrical coordinates (Y, R, 0). The scalar Y represents the axial distance to the center of the tire 200 in the direction of the reference axis 201, defined by the orthogonal projection of the material point of the tire 100 onto the reference axis 201. A radial plane 214 is defined, making an angle of 0 with respect to the vertical plane 213 around the reference axis 201. The material point of the tire 100 is located in this radial plane 214 by the distance R to the center of the tire 200 in the direction perpendicular to the reference axis 201, identified by the orthogonal projection of this material point onto the radial axis 204. The unit vector perpendicular to the radial plane 214 and forming a right-handed trihedron with the unit vectors of the axial direction 201 and the radial direction 204 represents the circumferential direction of the tire 100.

[0061] This tire 100 has on its radially inner surface 130 a fastening device 50 which is attached to the surface 130 by bonding according to conventional prior art techniques when the fastening device 50 is made of elastomeric material. The fastening device 50 is fixed at the apex S of the tire casing 100, which improves its durability since the fastening device thus positioned causes fewer problems during the mounting or dismounting of the wheel on the tire casing 100. Indeed, the fastening device 50 is located in an area away from the ribs B of the tire casing 100. Here, the fastening device 50 is equipped with an electronic system 1 within its open volume, which constitutes a housing adapted to receive the electronic system. As a result, the tire casing 100 is ready to be mounted on a wheel to form a complete assembly.The electronic system 1 can deliver various functions such as the identification of certain components like the electronic organ itself, the pneumatic system.

[0062] But the electronic system 1 can also be equipped with a pressure and / or temperature sensor to evaluate the inflation pressure of the assembled tire. Finally, it can also be equipped with a sensor that directly measures the curvature of the tire, such as an accelerometer or a flexometer, allowing the determination of tire usage parameters such as angular velocity, mileage, and applied static load. All or part of these parameters make it possible to identify tire performance characteristics such as wear, its adhesion or intrinsic properties of the ground on which the tire rolls.

Claims

1. Demands Method (1000) for manufacturing a sub-component (120) of an encapsulation device for the electronic elements of an electronic system (1) for pneumatics (100) comprising the following steps: - Production of a rigid housing (300) by heating and then injecting a thermoplastic into a first mold (600) comprising at least two dies (601, 602): • The first matrix (601) comprising a first surface (611), defining a first surface S 1(311) of the rigid housing (300), having a first cylindrical element (612) of diameter DI projecting along a first axis of revolution (614); • The second die (602) comprising a second surface (621), defining a second surface S2 (321) of the rigid housing (300), having a second cylindrical element (622) in projection, with axis of revolution (624) which can be coaxial with the first axis of revolution (614) when closing the first mold, with diameter D2 greater than the diameter DI of the first cylindrical element (612) and the second cylindrical element (622) extends axially over a height H2; • At least one of the two projecting elements (612) extending axially in the form of a cylinder (632) coaxial with the axis of revolution (614) of the cylindrical element (612) over a diameter D3 smaller than the two diameters DI and D2 of the cylindrical elements (612, 622) over a length greater than or equal to the distance between the first two cylindrical elements (612, 622) when the mold is closed, preferably the other projecting element (622) having a cylindrical recess (642) coaxial with the cylindrical element (622) with a diameter matched to diameter D3; and Production of sub-component (150) by injection molding via a nozzle and then cooling of a thermoelastic elastomer in a second mold (400) suitable for receiving the rigid housing (300), the second mold (400) comprising at least two dies (401, 402): • At least a third die (401) comprising a third surface (411) bearing on the first surface (311) of the rigid housing (300) and obstructing the cylindrical orifice (301) of the rigid housing (300); • At least one fourth matrix (402) comprising a fourth surface (421) bearing on the second surface (321) of the rigid housing (300), this second face (421) having a non-through cylindrical orifice (422) whose axis of revolution (424) is coaxial with the axis of revolution (304) of the cylindrical orifice (301) of the rigid housing (300) and whose diameter is greater than or equal to the diameter of the orifice (301) of the rigid housing (300) and extending along the axis of revolution (304) over a height H3;• At least one third die (401) or at least one fourth die (402) comprising a straight insert (502) coaxial to the axis of rotation (304) of the orifice (301) of the rigid housing (300), extending at least to the bottom of the cylindrical orifice (422) of the at least fourth die (402) or at least to the first face (411) of the fourth die; and - The insert (502) is coated with a material that is chemically inert with respect to the thermoelastic elastomer.

2. Method of manufacturing a sub-component of an encapsulation device for electronic elements of an electronic system for pneumatics according to claim 1 in which the outside diameter of the insert (502) is less than one-third of the diameter D3, preferably, the insert (502) is cylindrical in shape.

3. Method for manufacturing a sub-component of a device for encapsulating the electronic elements of an electronic system for pneumatic according to any one of claims 1 to 2 wherein the axial height H2 of the second element (622) is greater than 0.5 millimeters, preferably greater than or equal to 0.8 millimeters.

4. Method of manufacturing a sub-component of an encapsulation device for electronic elements of an electronic system for pneumatics according to any one of claims 1 to 3 wherein the axial height H3 of the non-through orifice (422) of at least a fourth die is between 0.8 and 1.3 millimeters.

5. Subcomponent (120) of an encapsulation device for the electronic elements of an electronic system (1) for pneumatics (100) comprising: - A rigid housing (300) comprising: • A first surface (311) and a second surface (321) separated by a thickness E of material; • Said rigid housing (300) comprising at least one cylindrical through-hole (350) about an axis of revolution (351) from the first surface (311) to the second surface (321); - An elastic seal (150) cylindrical about an axis of revolution (154), inserted in the through-hole (350) of the rigid housing (300) and extending perpendicularly away from the second surface (321) of the rigid housing (300) over a distance H3;Characterized in that the orifice (350) of the rigid housing (300) has a first shoulder (320) from the first surface SI (311) over a radial thickness E1, in that the orifice (350) of the rigid housing (300) has a second shoulder (330) from the second surface S2 (321) over a radial thickness E2, in that the orifice (350) extends outwards from this second shoulder (330) over a height H2, in that the elastic seal (150) comprises a cylindrical orifice (151) coaxial with the axis of revolution (154) and is coaxial with the axis of rotation (351) of the orifice (350) passing through the rigid housing (300), and in that the elastic seal (150) is in direct contact with the rigid housing (300) over the entire orifice (350) passing through the rigid housing (300).;

6. Subcomponent (120) of a device for encapsulating the electronic elements of an electronic system (1) according to claim 5 in which the rigid housing (300) is made of polyamide, the elastic seal (150) is made of a thermoelastic elastomer included in the group comprising thermoplastic elastomers, vulcanized thermoplastic elastomers.

7. Sub-component (120) of an encapsulation device for the electronic elements of an electronic system (1) according to any one of claims 5 to 6 in which the opening of the elastic seal (150) is cylindrical in shape and of diameter between 0.8 millimeters and 1.5 millimeters, preferably between 1 millimeter and 1.3 millimeters.

8. Electronic system (1) for pneumatics comprising: • An encapsulation device comprising: • A subcomponent (120) according to any one of claims 5 to 7 • A second rigid housing (101) impermeably connected to the subcomponent (120) on a closed contour (160); • Electronic components contained in the encapsulation device comprising at least one sensor (2) for measuring a physical parameter of a fluid; Characterized in that the at least one measuring sensor (2) is in contact with the elastic seal (150) of the subcomponent (120) arranged so that the active part of the at least one measuring sensor (2) is in fluidic communication with a medium external to the electronic system (1) via the orifice (151) of the elastic seal (150).

9. A tire (100) comprising an electronic system (1) according to claim 8, wherein the tire (100) having an axis of rotation (201), being delimited by an external surface (140) radially external to the tire (100) with respect to the axis of rotation (201) and an internal surface (130) located radially internal to the tire (100), and comprising a crest (S) adapted to be in contact with the ground, two sidewalls (F) situated on either side of the crest (S) and two beads (B) each located at the other end of each sidewall (F) adapted to be in contact with a wheel rim, the electronic system (1) is fixed to the internal surface (130) of the tire (100), preferably tiellement at the level of the summit (S), arranged so that the orifice (151) of the elastic joint (150) is free.

10. Tire (100) according to claim 9 wherein the attachment on the internal surface (130) of the electronic system (1) is achieved by means of a fastening device (50) comprising a sole whose external surface is in contact with the tire (100) and whose internal surface forms with at least one lateral retaining wall a cavity suitable for receiving the electronic system (1).

11. Assembly comprising a tire (100) having an axis of rotation (201), being delimited by an external surface (140) radially external to the tire (100) with respect to the axis of rotation (201) and an internal surface (130) located radially internal to the tire (100), and comprising a crest (S) adapted to be in contact with the ground, two sidewalls (F) situated on either side of the crest (S) and two beads (B) each located at the other end of each sidewall (F), and a wheel, the wheel comprising an axisymmetric rim about the axis of rotation (201) of the tire (100) and a wheel disc, the internal surface (130) of the tire (100) and the external surface of the rim delimiting a fluidic cavity of the assembly in fluidic communication with the electronic system (1) according to claim 10, arranged such that the orifice (151) of the elastic joint (150) opens into the fluidic cavity.

12. Assembly mounted according to claim 11 in which the electronic system (1) is fixed on the wheel, preferably on the wheel rim.

13. Assembly mounted according to claim 11 in which the electronic system (1) is fixed on the internal surface (130) of the tire (100), preferably at the top (S).

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