DEVICE FOR SECURING AN ELECTRONIC UNIT TO A TYRE AND A TYRE COMPRISING AN ELECTRONIC UNIT

Abstract

A device for securing an electronic unit to a tyre comprises a base formed by a layer of elastomeric material on whichby means of a structural adhesivea module comprising the electronic unit is glued. The lower surface of the elastomeric material base, opposite to the surface the module is glued to, and which is intended for being glued to the tyre's surface, is instead coated by means of a pressure sensitive adhesive (PSA). It has also an area which is greater than the surface area of the module glued to the base.

Claims

1-15. (canceled)

16. A securing device for securing an electronic unit to a tyre, comprising: a base formed by a layer of elastomeric material, and a module to house the electronic unit, wherein: the base comprises an upper surface and a lower surface; the module comprises a lower surface glued to the upper surface of the base by a structural adhesive; the lower surface of the base is coated with a pressure-sensitive adhesive; and the lower surface of the base has a greater area than an area of the lower surface of the module.

17. The device according to claim 16, wherein the elastomeric material comprises a plurality of reinforcing elements.

18. The device according to claim 17, wherein the plurality of reinforcing elements comprise filaments, textile cords, or metallic cords.

19. The device according to claim 18, wherein the filaments or textile cords are made of one or more of the following materials: aramid, rayon, polyester, nylon, or lyocell.

20. The device according to claim 17, wherein the plurality of reinforcing elements are arranged in the base and have a density between 30 cords/dm and 500 cords/dm.

21. The device according to claim 16, wherein the base has a circular or oval shape.

22. The device according to claim 16, wherein the area of the lower surface of the base is at least equal to 130% of the area of the lower surface of the module.

23. The device according to claim 22, wherein the area of the lower surface of the base is at least equal to 200% of the area of the lower surface of the module.

24. The device according to claim 16, wherein the module comprises a rigid body for housing the electronic unit.

25. The device according to claim 16, wherein the module comprises an elastomeric material body for housing the electronic unit.

26. A tyre comprising: an inner surface and an electronic unit, wherein the electronic unit is in a securing device, wherein the securing device comprises a base formed by a layer of elastomeric material and a module comprising the electronic unit, wherein: the base comprises an upper surface and a lower surface; the module comprises a lower surface glued to the upper surface of the base by a structural adhesive; the lower surface of the base is coated with a pressure-sensitive adhesive; and the lower surface of the base has a greater area than an area of the lower surface of the module, and the securing device is fixed to the inner surface of the tyre by the lower surface of the base and the pressure sensitive adhesive.

27. The tyre according to claim 26, wherein the layer of elastomeric material comprises a plurality of reinforcing elements, and the securing device is fixed to the inner surface, and wherein the plurality of reinforcing elements are arranged substantially according to a circumferential direction of the tyre.

28. The tyre according to claim 26, wherein the base has an elongated shape, and the securing device is fixed to the inner surface, and wherein a greater dimension of the base is disposed substantially according to a circumferential direction of the tyre.

29. The tyre according claim 26, wherein the lower surface of the module has an elongated shape, and the securing device is fixed to the inner surface, and wherein a greater dimension of the lower surface of the module is arranged substantially according to an axial direction of the tyre.

30. The tyre according to claim 26, wherein the securing device is fixed to a portion of the inner surface opposite to a tread of the tyre.

Description

BRIEF DESCRIPTION OF THE FIGURES

[0040] Further characteristics and advantages of the present invention will become apparent from the following detailed descriptions of some embodiments thereof, which are given only by way of non-limiting examples. The description will refer to the accompanying figures, wherein:

[0041] FIG. 1 schematically shows an electronic unit comprising at least one sensor for tyre monitoring;

[0042] FIG. 2 shows a tyre monitoring device comprising a securing device according to a first embodiment of the invention;

[0043] FIG. 3 is a plan view of the monitoring device of FIG. 2;

[0044] FIG. 4 schematically shows a section of the monitoring device of FIGS. 2-3 along section A-A;

[0045] FIG. 5 schematically shows a section of monitoring device of FIGS. 2-3 along section B-B;

[0046] FIG. 6 shows a tyre monitoring device comprising a securing device according to a second embodiment of the invention;

[0047] FIG. 7 shows a tyre with the monitoring device of FIG. 6 glued to its inner surface.

DETAILED DESCRIPTION OF SOME EXAMPLES OF THE INVENTION

[0048] With reference to the enclosed figures, reference number 1 comprehensively indicates a monitoring device for tyres of vehicle wheels.

[0049] The monitoring device 1 firstly comprises an electronic unit 10, suitable for detecting at least one characteristic variable of a tyre and for transmitting at least one corresponding parameter representative of said detected variable. For this purpose, electronic unit 10 may be provided with at least one sensor 11 suitable for the detection of said at least one characteristic variable, operatively associated to a processing/transmission system 12 of said at least one parameter.

[0050] The at least one sensor 11 can be, for example, a temperature sensor, and/or a pressure sensor, and/or a sensor capable of measuring the deformations undergone by the tyre during rolling, such as for example a strain gauge, or an accelerometer, an optical sensor able to detect displacements, a magneto-resistive sensor, an inertial sensor, a gyroscope, etc.

[0051] The processing/transmission system 12, operatively connected to said at least one sensor 11, provides for acquiring and processing the data detected by the latter. After processing, the processing/transmission system 12 provides for the transmission of the parameter or of the parameters characteristic of the variable to be monitored outside of the tyre.

[0052] The processing/transmission system 12 preferably comprises a microprocessor, an antenna and other circuitry necessary to carry out processing and/or analysis of the signals coming from the at least one sensor 11, so as to make the same suitable for the transmission of data from the monitoring device 1 to a receiver located on board a vehicle.

[0053] In one embodiment the data made available by sensor 11 can be processed directly by the system 12, advantageously provided with a suitable microprocessor or integrated circuit (for example of the ASICApplication Specific Integrated Circuit type).

[0054] The processing/transmission system 12 thus enables communication with the instrumentation on board the vehicle, for example in a periodic manner, so that all the relevant information can be provided to the driver and/or to a vehicle control system, and/or so as to activate or adjust to the best alarm systems and/or vehicle dynamics control systems, braking, etc.

[0055] This communication can be either unidirectional (from electronic unit 10 to the instrumentation on board the vehicle), or bidirectional.

[0056] The monitoring device 1 further comprises a securing device 20, having the aim of maintaining the electronic unit 10 fastened to a portion of the tyre.

[0057] In the embodiments shown in the figures, the securing device 20 comprises a base 30 and a module 40 where the electronic unit 10 is housed. In the embodiments shown in the figures, the electronic unit is arranged above module 40 (for example by gluing, and/or interlocking, and/or screwing on a suitable thread). The electronic unit's housing 10 in module 40 is not however critical for the present invention and may be prepared as best convenient for the skilled technician, according to the required specifications. For example, module 40 may completely enclose electronic unit 10, so as to make it inaccessible or irreplaceable. The base 30 of the securing device 20 is formed by a single layer of elastomeric material. Preferably, the base 30 has a perimeter free of sharp edges and/or portions with small curve radii. In the embodiment shown in the figures, the base 30 has a circular (FIGS. 2-5) or oval shape (FIGS. 6-7). In general, it may be preferable to prepare the base 30 with an elongated shape, for example oval or substantially rectangular with rounded edges, etc.

[0058] In the preferred embodiments schematically shown in FIGS. 2-5, the layer of elastomeric material forming the base 30 comprises a plurality of elongated reinforcing elements 31, for example textile filaments or cords, made of aramid, and/or rayon, and/or polyester, and/or nylon, and/or lyocell. Alternatively, the elongated reinforcing elements 31 can also be made by means of or comprise metal filaments or cords, such as made of steel. The elongated reinforcing elements 31 are embedded within the layer of elastomeric material, and arranged substantially parallel to each other. Naturally, the embodiment shown in FIGS. 6-7 can also comprise a base 30 embedding elongated reinforcing elements as described above.

[0059] For the purposes of gluing the securing device 20 and/or the monitoring device 1 to the inner surface of the tyre, the lower surface 32 of the base 30 is coated with a pressure sensitive adhesive (PSA). In preferred embodiments, the PSA can be an acrylic adhesive, a silicone adhesive, a butyl adhesive, a natural rubber-based adhesive, a block copolymer based adhesive. Preferably, the PSA is disposed as a layer on the entire lower surface 32 of the base 30. For the purposes of protecting the PSA, a removable film can be disposed, such as a polyethylene or polypropylene or paper film, coated with a non-stick layer. When it is time to glue the securing device 20 and/or the monitoring device 1 to the inner surface of the tyre, this protective film can be removed so that the PSA layer is faced to inner surface of the tyre at the chosen portion for the gluing. Gluing is then carried out simply by applying pressure to the securing device 20 against the inner surface of the tyre so as to activate the PSA and form the adhesive layer.

[0060] The lower surface 41 of module 40 is glued to the upper surface 33 of the base 30 by means of a structural adhesive. This structural adhesive can be for example a cyanoacrylate-based adhesive, a polyurethane adhesive, an epoxy or acrylic adhesive. The gluing of the module 40 to the base 30 can advantageously take place prior to gluing the entire securing device 20 and/or the monitoring device 1 to the inner surface of the tyre. In doing so, the correct formation of the polymerized adhesive interface layer between the lower surface 41 of the module 40 and the upper surface 33 of the base 30 can take place using the correct environmental conditions, the correct positioning of the module 40 and of the base 30 and the time necessary according to the chosen type of adhesive, so as to create a strong bond between the base 30 and the module 40. With the gluing of the module 40 on the base 30 (and possibly with the housing of the electronic unit 10 in module 40), the securing device 20 and/or the monitoring device 1 are advantageously formed as objects per se (for example in kit), ready to be glued, by means of the PSA arranged on the lower surface 33 of the base 30 of the securing device 20, to the tyre's inner surface.

[0061] For the purpose of having a stable housing of the electronic unit 10, the module 40 may comprise a rigid body. For example, the module 40 can be made of plastic material, and/or with resins (e.g. epoxy or polyurethane resins), and/or in sufficiently rigid elastomeric material, provided that such materials are compatible with the structural adhesive used for gluing the module 40 to the base 30.

[0062] In the embodiments shown in the figures, the module 40 has a substantially cylindrical shape.

[0063] In some embodiments (not shown in the figures), the module 40 can also comprise a body or a protective shell in elastomeric material suitable for the housing of the electronic unit (for example a body or a protective shell as described in patent applications WO2006/103706, WO2007/000781, WO2007/121768, WO2010/043264, WO2013/098711, WO2013/098712, WO2015/019283, WO2015/019288 in the name of the same Applicant). For example, a protective shell of non-rigid elastomeric material can completely enclose the electronic unit 10 to further the protect electronic unit 10 itself from shocks or stresses transmitted from the tyre's inner surface during rolling. Such protective shell can then be glued, by means of the structural adhesive, to the upper surface 33 of the base 30.

[0064] In the embodiments shown in the figures, the lower surface 41 of the module 40 has an elliptical shape. This can increase the bonding surface of the module 40 to the base 30 without significantly increasing the weight of module 40, but is not considered necessary for the purposes of the invention. Moreover, other elongated forms can be advantageously used, such as a substantially rectangular shape. As it can be seen from the sections shown in FIGS. 4-5, the elongated shape of the lower surface 41 of module 40 can be obtained by means of a widened, tapering portion which extends in only one direction. Preferably, the module 40 is glued to the base 30 in such a way that the greatest dimension of the lower surface 41 is arranged substantially perpendicular to the extension direction of the elongated reinforcing elements 31. In other embodiments (not shown), a widening of the lower surface 41 with respect to the rest of the body of module 40 can be carried out in multiple directions, or even in each direction.

[0065] As shown in the figures, the lower surface 32 of the base 30 has an area greater than the area of the lower surface 41 of the module 40. Preferably, the area of the lower surface 32 of the base 30 is at least equal to 130%, preferably at least equal to 200%, even more preferably at least equal to 300% of the area of the lower surface 41 of the module 40. The lower surface 32 of the base 30 is that intended for adhesion to the tyre's inner surface, and its increased area allows a stable bond to be obtained of the securing device 20 and/or of the monitoring device 1 to the tyre's inner surface.

[0066] FIG. 7 shows the monitoring device 1 fixed to the radially inner surface 100a of a tyre 100. It is noticed that the sizes of the monitoring device 1 have been deliberately increased compared to the sizes of tyre 100 in order to make the figure easier to read.

[0067] The monitoring device 1 is glued to inner surface 100a of tyre 100 through the securing device described above in reference to FIG. 6, and in particular by means of gluing the lower surface of the base of the securing device to inner surface 100a of tyre 100. The gluing is carried out by means of the pressure sensitive adhesive layer arranged on the lower surface of the base of the securing device.

[0068] In the embodiment shown in the figure, the monitoring device 1 is fixed to a portion of the inner surface 100a opposite to the tread of the tyre 100. More particularly, the monitoring device 1 is fixed to a portion of the inner surface at or across the tyre's equatorial plane.

[0069] The base of the securing device, having elongated shape in the embodiment shown in the figure, is fixed to the inner surface 100a of tyre 100 such that its greater size is arranged substantially according to a circumferential direction of the tyre 100.

[0070] Furthermore, in this preferred embodiment, the monitoring device 1 is fixed to the inner surface 100a of tyre 100 such that the elongated reinforcing elements embedded in the base of the securing device are arranged substantially according to a circumferential direction of the tyre 100.

[0071] The monitoring device 1 is further fixed to the inner surface 100a of tyre 100 such that the lower surface of the module housing the electronic unit, having elongated shape in the embodiment shown in the figure, is arranged in such a manner that its greater size extends substantially according to an axial direction of the tyre 100.

[0072] In preferred embodiments, before gluing the securing device and/or the monitoring device 1, the portion of inner surface 100a of tyre 100 intended for the gluing is cleaned from substances that may jeopardize the device's adhesion, such as dust, dirt and/or residues of releasing agents used during the tyre's vulcanization. This can be achieved, for example, by cleaning with detergents and/or solvents, and/or with mechanical action, and/or with polishing action through laser.

[0073] In another embodiment, a protective film, for example a nylon or polyester film, can be arranged on the green tyre prior to vulcanization, at the portion of inner surface of the tyre intended for the gluing of the securing device and/or of the monitoring device. The protective film maintains the portion of the tyre's inner surface substantially free from pollution by releasing agents (or in any case from dirty or undesired substances) used in the vulcanization process, remaining adhered to the finished tyre at the end of vulcanization. Before gluing the securing device and/or the monitoring device 1, the film is removed so as to expose a clean portion of inner surface 100a of tyre 100 for the gluing of the securing device and/or of the monitoring device 1.

[0074] In use, during rolling of tyre 100, the electronic unit contained in the monitoring device 1 provides for detecting and transmitting the envisaged data. Monitoring device 1 is subjected to very significant stresses, in particular in the circumferential direction, when it passes in the footprint's entrance/exit area. The stresses caused by the rolling of the tyre 100 are transmitted to the inner surface 100a and then to the monitoring device 1. The presence of the base with an increased surface area allows for a strong bond of the monitoring device 1 despite the fact that adhesion is carried out by means of a pressure sensitive adhesive. The adhesion layer placed at the interface between the base and the module housing the electronic unit, carried out by means of the structural adhesive, and, where present, the elongated reinforcing elements embedded in the base, allows these stresses to be counteracted so as to form a whole set that is substantially non-deformable in the circumferential direction. In this way, the formation of cracks and/or detachment portions in the securing device is effectively counteracted, so as to maintain a strong fastening of the monitoring device 1 to the inner surface 100a of tyre 100.

[0075] Herein below are two complete examples of securing device according to the invention, which the Applicant has verified to be resistant during rolling at high speeds in indoor tests, up to speeds higher than 300 km/h: [0076] 1) Base: single layer of reinforced elastomeric material, circular [0077] Diameter: 55 mm [0078] Base lower surface area: 23.8 cm.sup.2 [0079] Base thickness: 0.5 mm [0080] Elongated reinforcing elements: aramid cords, linear density 840/2 dTex, cord [0081] density 110 cords/dm [0082] Pressure sensitive adhesive: acrylic 3M 9472FL [0083] Body of the electronic unit housing module: rigid nylon cylinder [0084] External cylinder diameter: 24 mm [0085] Shape of the housing module's lower surface: oval [0086] Greater size: 40 mm [0087] Smaller size: 24 mm [0088] Lower surface area of the housing module: 7.7 cm.sup.2 [0089] Structural adhesive: cyanoacrylate Cyberbond Apollo 2014 [0090] Ratio % base lower surface area/module lower surface area: 23.8/7.7%=309% [0091] 2) Base: single layer of reinforced elastomeric material, oval [0092] Greater size: 95 mm [0093] Smaller size: 55 mm [0094] Base lower surface area: 41 cm.sup.2 [0095] Base thickness: 0.5 mm [0096] Elongated reinforcing elements: aramid cords, linear density 840/2 dTex, cord [0097] density 110 cords/dm [0098] Pressure sensitive adhesive: acrylic 3M 9472FL [0099] Body of the electronic unit housing module: rigid nylon cylinder [0100] External cylinder diameter: 24 mm [0101] Shape of the housing module's lower surface: oval [0102] Greater size: 40 mm [0103] Smaller size: 24 mm [0104] Housing module lower surface area: 7.7 cm.sup.2 [0105] Structural adhesive: cyanoacrylate Cyberbond Apollo 2014 [0106] Ratio % base lower surface area/module lower surface area: 41/7.7%=532%