TYRE COMPRISING A MONITORING DEVICE

Abstract

Tyre (10) comprising a monitoring device (1) which comprises a housing portion (2) and a base portion (3), the base portion (3) having a coupling surface (4) in single piece intended for fixing the monitoring device to the tyre, wherein the monitoring device (1) comprises an electronic unit (8) housed in the housing portion (2), wherein the monitoring device (1) is fixed to an inner surface (15) of the tyre (10) at a crown portion (16) of the tyre by an adhesive (6) interposed between the coupling surface (4) and the inner surface (15), wherein a first region (12) of the coupling surface (4) is covered by the adhesive (6) and a second region (13) of the coupling surface (4), complementary to the first region (12), is free of adhesive (6), and wherein the second region (13) is contained within a projection (5) of the housing portion (2) onto the coupling surface (4).

Claims

1.-11. (canceled)

12. A tyre comprising a monitoring device, wherein the monitoring device comprises: a housing portion and a base portion mutually integral, the base portion having a coupling surface in a single-piece intended for fixing the monitoring device to the tyre, wherein a projection of the housing portion onto the coupling surface has an extension lower than the coupling surface, and an electronic unit housed in the housing portion, wherein the monitoring device is fixed to an inner surface of the tyre at a crown portion of the tyre by an adhesive interposed between the coupling surface and the inner surface, wherein a first region of the coupling surface is covered by the adhesive and a second region of the coupling surface, complementary to the first region, is free of the adhesive, and wherein the second region is contained within the projection of the housing portion onto the coupling surface.

13. The tyre according to claim 12, wherein the first region entirely surrounds the second region, wherein the first region is continuous, or the second region is continuous, or both the first and the second regions are continuous, and wherein a projection of a centre of mass of the housing portion onto the coupling surface falls in a central position of the second region.

14. The tyre according to claim 12, wherein the housing portion is arranged in substantially central position of the base portion, and wherein the second region is arranged in substantially central position of the projection of the housing portion.

15. The tyre according to claim 12, wherein the second region has a plan extension greater than or equal to 45%, and less than or equal to 95%, of the projection of the housing portion, and wherein a shape of the second region reproduces, with a scale factor, a shape of the projection of the housing portion.

16. The tyre according to claim 12, wherein a distance (D) measured along the coupling surface between an edge of the second region and an ideal edge of the projection of the housing portion is equal to at least 1 mm, along an entire development of the edge of the second region, and wherein the distance (D) is at most mm.

17. The tyre according to claim 12, wherein the adhesive is a pressure sensitive adhesive chosen from an acrylic adhesive, a silicone adhesive, a butyl adhesive, a natural rubber-based adhesive, and a block copolymer-based adhesive.

18. The tyre according to claim 18, wherein the adhesive has a thickness less than or equal to 200 μm.

19. The tyre according to claim 12, wherein the housing portion comprises a rigid body suitable for housing the electronic unit, wherein the projection of the housing portion coincides with a projection of the rigid body, wherein the electronic unit comprises at least one sensor for sensing at least one physical quantity: temperature, pressure, acceleration, and deformation; a processing unit; and a transceiver, wherein the monitoring device comprises an electric power supplier electrically connected to the electronic unit, wherein the base portion has a perimetral edge free of corners, cusps, or portions with small curvature radii, or corners, cusps, and portions with small curvature radii, wherein the housing portion has substantially cylindrical or prismatic shape, wherein the base portion comprises a plurality of reinforcing elements comprising textile filaments or cords, or metallic filaments, or cords, wherein the textile filaments or cords are made of one or more textile materials chosen from: aramid, rayon, polyester, nylon, and lyocell, and wherein the reinforcing elements are arranged with a density ranging from 30 cords/dm to 500 cords/dm.

20. The tyre according to claim 12, wherein the base portion has a circular or oval perimetral edge, or wherein the base portion has a perimetral edge with wavelike trend along a substantially circular or oval generating line.

21. The tyre according to claim 12, wherein the monitoring device comprises an encapsulation material which at least partially encloses the electronic unit, wherein the encapsulation material realizes with continuity at least part of the housing portion and at least part of the base portion to make the housing portion and the base portion mutually integral, wherein the encapsulation material is a polyurethane material or a polyurea, and wherein reinforcing elements are associated with, or incorporated into, the encapsulation material.

22. The tyre according to claim 12, wherein the base portion is made by a layer of elastomeric material, wherein the housing portion and the base portion are distinct from each other and made mutually integral with a structural adhesive, and wherein the structural adhesive is chosen from a cyanoacrylate-based adhesive, a polyurethane-based adhesive, an epoxy adhesive, and an acrylic adhesive.

Description

BRIEF DESCRIPTION OF THE FIGURES

[0057] FIG. 1 shows a schematic, perspective and partial view of a section of tyre comprising a monitoring device according to the present invention;

[0058] FIG. 2 schematically shows a side sectional view of an embodiment of the monitoring device according to the present invention applied to a portion of tyre;

[0059] FIG. 3 schematically shows a bottom view of the monitoring device of FIG. 2.

DETAILED DESCRIPTION OF SOME EMBODIMENTS OF THE INVENTION

[0060] The features and the advantages of the present invention will be further apparent from the following detailed description of some embodiments, presented by way of non-limiting example of the present invention, with reference to the attached figures.

[0061] In FIG. 1, with the reference number 10 it is shown a tyre (in partial perspective section) comprising a monitoring device 1 according to the present invention.

[0062] Exemplarily the monitoring device 1 comprises a housing portion 2 and a base portion 3 mutually integral, the base portion 3 having a coupling surface 4 in single-piece intended for fixing the monitoring device to the tyre (exemplarily coinciding with a base face of the base portion facing the tyre), wherein a projection 5 (shown by dashed line in FIG. 3) of the housing portion 2 onto the coupling surface 4 has an extension lower than the coupling surface 4.

[0063] Exemplarily the base portion 3 has circular perimetral edge and the housing portion 2 comprises a rigid body 7 having cylindrical shape, wherein the housing portion 2 is exemplarily arranged in central position of the base portion (and of the coupling surface 4). Exemplarily an axis 100 of the rigid body 7 passes through a centre (not shown) of the base portion 3. Exemplarily (FIGS. 2 and 3) the projection 5 of the housing portion 2 coincides with a projection of the rigid body 7.

[0064] Exemplarily the monitoring device 1 comprises an electronic unit 8, schematically shown in FIG. 2, housed in the housing portion 2. Exemplarily the rigid body 7 is suitable for housing the electronic unit.

[0065] Exemplarily the monitoring device 1 comprises an electric power supplier 11 (exemplarily a button battery) electrically connected to the electronic unit 8.

[0066] Exemplarily the monitoring device 1 comprises an encapsulation material 9 (e.g. a polyurethane material) which realizes with continuity at least part of the housing portion 2, enclosing the electric power supplier 11 and at least partially the electronic unit 8, and entirely the base portion 3 (and the coupling surface 4) to make the housing portion and the base portion mutually integral. Exemplarily (not shown) the encapsulation material is poured in fluid form into the rigid body 7 to incorporate, after solidification, at least partially the electronic unit 8 and the electric power supplier 11 and to realize the base portion.

[0067] Exemplarily the base portion 3 comprises a plurality of reinforcing elements (not shown) incorporated into the encapsulation material (at least at the base portion).

[0068] The monitoring device exemplarily shown in FIG. 2 is of the type described in detail in the document WO2019/123118A1 in the name of the same Applicant.

[0069] In one alternative embodiment (not shown) the monitoring device can be of the type described in the document WO2018/065846A1 in the name of the same Applicant. In this embodiment, the base portion is made by a layer of elastomeric material (typically comprising a rubber reinforced with carbon black), and the housing portion and the base portion are distinct from each other and they are made mutually integral by gluing with structural adhesive (for example selected from the following: cyanoacrylate-based adhesive, polyurethane-based adhesive, epoxy adhesive, acrylic adhesive).

[0070] Exemplarily the electronic unit 8 comprises at least one sensor (not shown) for sensing at least one of the following physical quantities: temperature, pressure, acceleration, deformation; a processing unit (not shown); a transceiver (not shown). The structure and/or the functioning of these components will not be further described as they are substantially known (see for example the two aforementioned documents WO2019/123118A1 and WO2018/065846A1).

[0071] Exemplarily the monitoring device 1 is fixed to an inner surface 15 of the tyre 10 at a crown portion 16 of the tyre 10 (i.e. the portion of tyre placed at the tread band 17) by an adhesive 6 interposed between the coupling surface 4 and the inner surface 15.

[0072] Exemplarily a first region 12 (FIGS. 2 and 3) of the coupling surface 4 is covered by the adhesive 6 and a second region 13 of the coupling surface 4, complementary to the first region 12, is free of adhesive 6.

[0073] Preferably, the second region 13 is contained within the projection 5 of the housing portion 2 onto the coupling surface 4. For example, the second region 13 has circular shape concentric to the projection 5 of the housing portion 2, which is also circular. Exemplarily (not shown) a projection of a centre of mass of the housing portion 2 onto the coupling surface 4 falls in a central position of the second region 13.

[0074] Preferably, the first region 12 and the second region 13 are continuous. For example, the first region 12 has circular crown shape and completely surrounds the second region 13.

[0075] Exemplarily the second region 13 has a plan extension equal to about 80% of the projection 5 of the housing portion 2.

[0076] With reference to FIG. 3, it shows the subdivision of the coupling surface respectively in the first and in the second region (solid line), together with the plan encumbrances of the projection of the housing portion (dashed line). For the sake of better clarity, the extensions of the adhesive 6 and of the base portion 3 and of housing portion 2 of the monitoring device shown in FIG. 3 have been correlated by dashed lines to the surfaces of FIG. 3.

[0077] Exemplarily a distance D measured along the coupling surface 4 between an edge of the second region 13 and an ideal edge of the projection 5 of the housing portion 2 is equal to about 2.6 mm (exemplarily, given the cylindrical symmetry of the monitoring device 1, the distance D is a constant radial distance along an entire development of the edge of the second region).

[0078] Exemplarily the adhesive 6 is a pressure sensitive adhesive (PSA), chosen from the following: acrylic adhesive, silicone adhesive, butyl adhesive, natural rubber-based adhesive or block copolymer-based adhesive.

[0079] Exemplarily the adhesive 6 has a uniform thickness equal to about 80 μm (in FIG. 2 the thickness of the adhesive is shown not in scale for better clarity).

COMPARATIVE EXAMPLES

[0080] The spatially selective gluing according to the present invention was tested by the Applicant in three different experimental contexts, described below in detail in the comparative examples A, B, C and D.

[0081] For the experimental tests, monitoring devices of the type described in the document WO2019/123118A1 have been used, having a diameter of the base portion equal to mm, a diameter of the housing portion (e.g. diameter of the rigid body 7) equal to mm, and a surface extension of the second region equal to 80% of the projection of the housing portion.

[0082] The type of tyres used was front and rear tyres, produced by the same Applicant, suitable for sport vehicles.

[0083] In two of the three experimental contexts (namely for examples A and B), the results obtained by the spatially selective gluing were compared to those obtained by applying a complete gluing to the same type of monitoring device (i.e. 100% of the coupling surface covered with adhesive). The type of tyres used for the devices with complete gluing was the same as above.

[0084] In example C two spatially selective gluing according to the present invention having same surface extension of the second region, distinct from each other by the thickness of the adhesive applied to the coupling surface, were instead compared.

[0085] The test performed was one of those of example A.

Example A

[0086] The Applicant has performed an indoor high-speed thermomechanical cyclic fatigue test, based on the speed profiles of the certification tests GB/T (38° C. ambient temperature—1.7 m road wheel) and ECE (25° C. ambient temperature—2.0 m road wheel) for Y or (Y) tyres, which involves the rotation of the tyre under conditions that simulate the on-road application. The latter, in particular, is simulated through a wheel (called “road wheel”) respectively having the aforementioned diameters, on which the tyre is placed with contact, the tyre being in turn subjected to a (constant) load.

[0087] The test involves an initial ramp increase of the tyre rotation speed and the maintenance of the reached value for a first time interval, and subsequently the step increase of the speed and the maintenance of each speed value for a respective given time (in the example equal to 10 minutes) until reaching a speed of 300 km/h (the speeds are reported in terms of linear speeds corresponding to the rotation of the tyre).

[0088] In the present implementation, the test was hardened by continuing above 300 km/h, further increasing the speed by 10 km/h every 10 minutes until the failure of tyre and/or of the monitoring device.

[0089] The following table shows the comparison between the obtained results:

TABLE-US-00001 % % coupling extension surface Test second covered by Adhesive Tyre type type region adhesive thickness Result Type of test ending 245/35R20 A 100% 100% 300 μm 10′@310 km/h Failure of Pzero (ECE) monitoring device by breakage/detachment 245/35R20 A 100% 100% 120 μm 10′@320 km/h Failure of Pzero (ECE) monitoring device by breakage/detachment 245/35R20 A  63%  87% 120 μm 10′ @340 km/h Failure of Pzero (ECE) tyre/electronics 305/30R20 A 100% 100% 300 μm 10′@290 km/h Failure of Pzero (GB/T) monitoring device by breakage/detachment 305/30R20 A 100% 100% 120 μm 7′@300 km/h Failure of Pzero (GB/T) monitoring device by breakage/detachment 305/30R20 A  63%  87% 120 μm 5′@310 km/h Failure of Pzero (GB/T) tyre/electronics

[0090] Experimentally it is observed that the gluing of the monitoring device according to the present invention allows to achieve higher speeds than the speeds achieved in presence of complete gluing of the monitoring device. It is also noted that for the tyres comprising the monitoring device with spatially selective gluing, the end of the test is due to the failure of the tyre and/or of the electronics (e.g. due to local overheating), but not to the detachment and/or to the breakage of the monitoring device (as instead occurs in cases of complete gluing).

Example B

[0091] The gluing tightness of the monitoring device was evaluated by an indoor test of validation of the maximum homologation speed of the tyre according to GB/T (38° C. ambient temperature—1.7 m road wheel, first table) or ECE (25° C. ambient temperature—2.0 m road wheel, second table) standard, which involves (using an experimental apparatus similar to that described above) the ramp increase of the speed until reaching the maximum homologation linear speed of the given type of tyre (exemplarily equal to 350 km/h) and the maintenance of this homologation speed for a given time interval (also in this case the speeds are reported in terms of linear speeds).

[0092] The following table shows the comparison between the obtained results:

TABLE-US-00002 % % coupling extension surface Test second covered by Adhesive Test Tyre type type region adhesive thickness result Type of test ending 245/35R20 B 100% 100% 120 μm Fail Failure of Pzero (GB/T) monitoring device by breakage/detachment 245/35R20 B  63%  87% 120 μm Pass — Pzero (GB/T) 305/30R20 B 100% 100% 120 μm Fail Failure of Pzero (GB/T) monitoring device by breakage/detachment 305/30R20 B  63%  87% 120 μm Pass — Pzero (GB/T)

[0093] The gluing method according to the present invention allows the tyre comprising the monitoring device to pass the test, while the breakage and/or the detachment of the monitoring device is observed in case of complete gluing of the latter.

[0094] Conversely, the following table reports the experimental results obtained with further types of tyres incorporating monitoring devices with spatially selective gluing according to the present invention and subjected to the aforementioned test of validation of the maximum homologation speed (according to ECE standard):

TABLE-US-00003 % % coupling Maximum extension surface achieved Test second covered by Adhesive Test speed Tyre type type region adhesive thickness result [km/h] 245/35R20 B 63% 87% 120 μm Pass 340 Trofeo (ECE) 305/30R20 B 63% 87% 120 μm Pass 340 Trofeo (ECE) 325/30R21 B 63% 87% 120 μm Pass 350 Trofeo (ECE) 295/30R20 B 63% 87% 120 μm Pass 340 Trofeo (ECE) 285/35R20 B 63% 87% 120 μm Pass 340 Trofeo (ECE) 225/35R19 B 63% 87% 120 μm Pass 340 Trofeo (ECE) 355/25ZR21 B 63% 87% 120 μm Pass 370 PZERO (ECE) 305/30R20 B 63% 87% 120 μm Pass 390 Prototype (ECE)

[0095] Also in this case, the gluing methodology according to the present invention has led to the pass of the test for all the used types of tyre.

Example C

[0096] The Applicant has also tested the effects of the variation of the adhesive thickness in monitoring devices having spatially selective gluing with the same extension of the second region. The indoor test performed is the same as performed in example A with GB/T certification test.

[0097] According to the Applicant, the use of a thinner adhesive thickness for a given surface covered by adhesive allows to further reduce the aforementioned adhesive accumulation phenomenon, which is believed to be the cause of the failure (e.g. detachment) of the monitoring device.

[0098] The following table shows the obtained results:

TABLE-US-00004 % % coupling extension surface Test Adhesive second covered by Type of Tyre type type thickness region adhesive Result test ending 305/30R20 A 120 μm 63% 87% 5′@310 km/h Failure of Pzero (GB/T) tyre/electronics 305/30R20 A 80 μm 63% 87% 7′@310 km/h Failure of Pzero (GB/T) tyre/electronics

[0099] The results show that an adhesive thickness equal to 80 μm allows, for a given rotation speed, to delay (increase of 2 minutes) the failure of the tyre and/or of the electronics of the monitoring device (experimentally occurred due to local overheating) with respect to an adhesive with thickness of 120 μm. Also in this case it is observed that the end of the test is due to the failure of the tyre and/or of the electronics, but not to the detachment of the monitoring device (which, having the spatially selective gluing according to the present invention, maintains the adhesion to the tyre).

Example D

[0100] Tyres comprising monitoring devices with spatially selective gluing with the two different thicknesses of adhesive (i.e. 80 μm and 120 μm) as tested in example C, have also been subjected by the Applicant to a fatigue test (i.e. a stress test of the tyre rolling in an overloaded condition with respect to the respective load index). The test result was positive for both the tyres. In particular, the tyre having an adhesive thickness equal to 120 μm lasted in the test for a time 25% greater than the time of the tyre having an adhesive thickness equal to 80 μm.

[0101] The choice of adhesive thickness may therefore depend on the intended use of the tyre. For example, for a racing tyre (e.g. motorsport applications) in which the use at very high speeds is essentially privileged, it may be appropriate to choose reduced adhesive thicknesses (e.g. 80 μm), while for applications for longer road use, it may be convenient to choose greater adhesive thicknesses (e.g. 120 μm).

[0102] In conclusion, thanks to the spatially selective gluing according to the present invention, it is possible to obtain considerable improvements on the adhesion efficiency of the monitoring device to the inner surface of the tyre in terms of maximum (linear) speed achieved and/or of duration of gluing for a given speed, with respect to the complete gluing of the monitoring device, also moving the causes of failure under responsibility of the tyre and/or of the electronics (e.g. local overheating) and not of the adhesion of the monitoring device, adhesion which maintains itself firm in all the performed tests.