DESCRIPTION

Technical sector

The present invention is advantageously applied to a pneumatic tyre equipped with an RFID label, i.e., with an identification label based on RFID ("Radio Frequency IDentification") technology, to which the discussion below will explicitly refer without thereby sacrificing general applicability.

Prior art

In recent years, so-called "smart" pneumatic tyres have emerged, which are capable of forming an active part of modern vehicles, supplying information concerning the type of pneumatic tyres mounted, information concerning the state of the pneumatic tyres and also information concerning ambient conditions. A "smart" pneumatic tyre is provided with an RFID ("Radio Frequency IDentification") label, which permits remote communication of information such as the identification, the characteristics and the history of the pneumatic tyre.

It has been proposed (for example, as described in the patent applications US2020070597A1, US20210016614A1 and EP4019241A2) to glue an RFID label onto the inner surface or onto the external surface of a sidewall of a pneumatic tyre; this solution is extremely simple from a design perspective and is applicable also to existing pneumatic tyres; however, by contrast, it does not guarantee that the transponder will not detach from the pneumatic tyre (especially when it is glued to the external surface) following the cyclical deformations to which the sidewall of a pneumatic tyre is subjected. It was also proposed (as described, for example, in the patent applications US20080289736A1, EP2186658A1 and EP1366931A2) to integrate a transponder into the structure of a pneumatic tyre, i.e., within the various layers that make up the pneumatic tyre.

The patent US7556074B2 describes a pneumatic tyre having a cavity formed in its interior for receiving a removable electronic monitoring module. The patent application EP3798020A1 describes a pneumatic tyre (1) having an overlap region in which an inner layer of the pneumatic tyre is overlapping.

Particularly in the case in which the RFID label is glued to the radially inner surface (made up of the innerliner) of a pneumatic tyre, it was observed that with a non-indifferent frequency there may be ruptures (cracks) in the innerliner near the zone in which the RFID label was glued.

Description of the invention

The object of the present invention is to supply a pneumatic tyre provided with an electronic device, this pneumatic tyre being free of the drawbacks described above, i.e., not being subject to the risk of detachments or ruptures of the innerliner near the zone in which the electronic device was applied and, at the same time, being easy and economical to produce.

According to the present invention, a pneumatic tyre equipped with an electronic device is provided as set forth in the appended claims.

The claims describe preferred embodiments of the present invention that form an integral part of the present description.

Brief description of the drawings

The present invention will now be described with reference to the attached drawings, which illustrate an exemplary, non-limiting embodiment, wherein:

• Figure 1 is a schematic cross-sectional view of a pneumatic tyre provided with an RFID label;

• Figures 2 and 3 are, respectively, a perspective view and a perspective exploded view of the RFID label of the pneumatic tyre of Fig. 1;

• Figure 4 is a schematic view of the structure of the pneumatic tyre of Fig. 1; and

• Figures 5 and 6 are two different schematic and lateral views of the pneumatic tyre of Fig. 1. Preferred embodiments of the invention

In Fig. 1, reference numeral 1 indicates as a whole a pneumatic tyre 1 comprising a toroidal carcass 2, which is partially folded onto itself and therefore has two lateral flaps (i.e., two layers superimposed on one another and jointly referred to as a "turn-up"). Two annular beads 3 are provided at opposite sides of the carcass 2, wherein each thereof is surrounded by the carcass 2. The carcass 2 supports an annular tread 4 with the interposition of a tread belt 5. Arranged within the carcass 2 is an innerliner 6 which is airtight, constitutes an inner lining and has the function of retaining the air within the tyre 1 in order to maintain the inflation pressure of the same tyre 1 over time. The carcass 2 supports a couple of lateral walls 7, each of which links a bead 3 to the tread 4.

The pneumatic tyre 1 is provided with an RFID ("Radio-Frequency IDentification") label 8, also called a "smart label," which is capable of memorizing information and/or acquiring signals related to the operating conditions or the state of the pneumatic tyre 1 and is capable of communicating via radio frequency. In other words, the RFID label 8 is configured to respond to the remote polling on the part of suitable fixed or portable apparatuses, called readers (or else, interrogators) or autonomously transmitting signals to a receiver; a reader or a receiver is capable of reading and/or modifying the information contained in the RFID label 8, communicating in radio frequency.

According to the illustration of Fig. 1, the RFID label 8 is arranged on a lateral wall 7 of the pneumatic tyre 1; according to other embodiments illustrated with dashed lines in Fig. 1, the RFID label 8 could be arranged on components of the pneumatic tyre 1 other than the lateral walls 7, such as the tread 4.

According to the illustration in Fig. 1, the RFID label 8 is glued on the innerliner 6, i.e., it is applied to the inner surface of the pneumatic tyre 1, which is constituted by the innerliner 6 (therefore, the RFID label 6 is in direct contact with the innerliner 6). In other words, the RFID label 8 is outside of the pneumatic tyre 1, i.e., it is not integrated within the pneumatic tyre 1 and it is applied (fixed, affixed) to a radially inner surface of the innerliner 6, i.e., on a surface of the innerliner 6 which is outside the pneumatic tyre 1 and therefore is in direct contact with the air within the pneumatic tyre 1 and therefore on the innermost free surface of the pneumatic tyre 1. According to different embodiment (not shown), the RFID label 8 is integrated in the interior of the pneumatic tyre 1, i.e., it is inserted between the components of the pneumatic tyre 1 during the construction of the pneumatic tyre 1 itself (for example, the RFID label 8 could be arranged between the carcass 2 and the innerliner 6 or between the carcass 2 and a sidewall 7).

According to the illustrations of Fig. 2 and 3, the RFID label 8 comprises an electronic circuit 9 (i.e., a microchip) provided with a non-volatile memory and an antenna 10 connected to the electronic circuit 9 (preferably the electronic circuit 9 and the antenna 10 constitute a transponder, i.e., the RFID label 8 is substantially a transponder); these components are inserted in a rubber enclosure made up of two strips 11 and 12 of rubber that are overlapped and pressed one onto the other.

The green components (carcass 2, tread belt 5, tread 4, innerliner 6...) of the pneumatic tyre 1 overlap one another to form a flat strip which is then wrapped (around, i.e., over an assembly drum of a construction machine) to form a cylinder, which is then deformed in order to assume the final toroidal shape. In particular, the strip, being wrapped in a ring, is connected onto itself, forming a plurality of joints (each component of the pneumatic tyre 1 is joined in a different position in order to avoid overlapping of the joints and therefore to avoid forming a great discontinuity at a single point). Among the various joints within the pneumatic tyre 1 and according to the illustration of Fig. 4, a joint 13 of the innerliner 6 is present; i.e., the innerliner 6 of the green pneumatic tyre 1 has a joint 13 in which the two opposing flaps of the innerliner 6 are joined to one another (by means of a slight overlap). The green pneumatic tyre 1 is then subjected to a vulcanization process in a suitable vulcanization mold.

The joint 13 confers a cylindrical shape to the innerliner 6 of the pneumatic tyre 1 and is axially oriented, i.e., it is parallel to the central axis of the pneumatic tyre 1 around which the pneumatic tyre 1 rotates during use.

According to the illustration of Fig. 5, the RFID label 8 is internally arranged in a zone 14 which is centered on the joint 13 (i.e., the joint 13 is arranged exactly at the center of the zone 14) and extends circumferentially, starting from the joint 13, for no more than 90° per side (i.e., the maximum extension of the zone 14 is 90° per side). In other words, the zone 14 has a maximum circumferential extension of 180° (therefore covers at most exactly half of the pneumatic tyre 1). According to an alternative embodiment, the zone 14 has a maximum circumferential extension of 150°, 120° or 90°; i.e., the zone 14 extends circumferentially, starting from the joint 13, for no more than 75°, 60° or 45° per side.

According to the illustration of Fig. 5, the RFID label 8 is preferably not overlapping the joint 13, i.e., (as better illustrated in Fig. 6) the RFID label 8 is arranged at a non-zero circumferential distance DI from the joint 13.

More generally and according to what is better illustrated in Fig. 6, a proximal end of the RFID label 8 is arranged at the circumferential distance DI from the joint 13 that is greater than 0° and at a distal end of the RFID label 8 (circumferentially opposite the proximal end) is arranged at a circumferential distance D2 from the joint 13 (greater than the circumferential distance DI) which is less than 90° (i.e., less than 75°, 60° or 45°). Obviously, the circumferential distance D2 is greater than the circumferential distance DI, because the circumferential extension of the RFID label 8 is included between the two circumferential distances DI and D2.

Before initiating the vulcanization process, a release agent (i.e., a lubricating liquid) is applied (sprayed) inside the pneumatic tyre 1 and has the purpose of preventing the adhesion (vulcanization) of the rubber of the innerliner 6 to the air chamber which is inflated within the pneumatic tyre 1 in order to apply the necessary mechanical pressure. After the process of application (spraying) of the release agent, as a general rule the green pneumatic tyres 1 to be vulcanized (i.e., ready to be vulcanized) should be arranged in a rack with a vertical orientation in which they may remain for a certain time (or even different times or several days). When the green pneumatic tyres 1 (to be vulcanized) are "parked" in the rack, the joint 13 is carefully arranged up high (i.e., at the highest point), that is, each pneumatic tyre 1 is oriented (turned) in such a way that the joint 13 is located at the top; the purpose of this orientation is that the release agent dripping by gravity does not accumulate near the joint 13 and instead accumulates in a zone of the pneumatic tyre 1 far from the joint 13 (and in general also from other joints). In fact, if the release agent were to accumulate or in any case were to flow copiously near the joint 13, it could end up penetrating into some micro-fissures of the joint 13, causing a premature formation of detachments or cracks of the innerliner 6 that in the short term would cause the indispensable impermeability of the pneumatic tyre 1 to be lost.

In the same way, if the release agent were to accumulate or in any case were to flow copiously near the RFID label 8, it could end up penetrating into the RFID label 8 and the innerliner 6, causing a premature formation of detachments or cracks of the innerliner 6 that in the short term would cause the indispensable impermeability of the pneumatic tyre 1 to be lost. Therefore, keeping the RFID label 8 in the zone 14 prevents the release agent from accumulating or in any case flowing copiously near the RFID label 8 and, as a result, prevents the potential formation of cracks (ruptures) in the innerliner 6 (i.e., prevents the rupture of the innerliner 6 due to the infiltration of release agent).

In the embodiment illustrated in the attached figures and described above, an RFID label 8 is applied to the radially inner surface of the innerliner 6 (which constitutes the innermost free surface of the pneumatic tyre 1); according to other embodiments (not shown), an electronic device different from the RFID label 8, for example an electronic device which constitutes a TMS ("Tire Mounted Sensor") or is a part of a TMS is applied to the radially inner surface of the innerliner (6) (which constitutes the innermost free surface of the pneumatic tyre 1).

The embodiments described herein may be combined without departing from the scope of protection of the present invention.

The pneumatic tyre 1 described above has many advantages. In the first place, the pneumatic tyre 1 described above has a minor defect of the innerliner 6 at the RFID label 8; this result is obtained by avoiding an accumulation of release agent near the RFID label 8 before the vulcanization process.

Furthermore, the pneumatic tyre 1 described above is of a particularly simple and economical implementation, because it does not require any additive components, just a focus (easily automatable) on the positioning of the RFID label 8.

List of reference numbers in the figures

1 tyre

2 carcass

3 beads

4 tread

5 tread belt

6 innerliner

7 sidewalls

8 RFID label

9 electronic circuit

10 antenna

11 rubber strip

12 rubber strip

13 joint

14 zone

DI circumferential distance

D2 circumferential distance