Method for producing tyres equipped with electronic devices

Abstract

A method of production of a pneumatic tyre (1) has the following steps: manufacturing a green pneumatic tyre (1) provided with an inner liner (6) which constitutes the inner lining and has the function of retaining air inside the pneumatic tyre (1); applying to the inner surface of the inner liner (6), which constitutes the innermost free surface of the green pneumatic tyre (1), an electronic device (8) inserted into a rubber support (11); applying to the inner surface of the inner liner (6) of the green pneumatic tyre (1) a release product (P) for the subsequent vulcanization process; and subjecting the green pneumatic tyre (1) to a vulcanization process. The amount of release product deposited is between 5 mg / cm 2 and 30 mg / cm 2 and the total thickness of the rubber support (11) of the electronic device (8) is between 0.5 mm and 1.5 mm.

Description

Technical Field

[0001] This invention relates to a method for producing pneumatic tires equipped with electronic devices.

[0002] This invention is advantageously applied to pneumatic tires equipped with RFID tags (i.e., identification tags based on RFID (“Radio Frequency Identification” technology), the discussion below will explicitly refer to such RFID tags without sacrificing general applicability. Background Technology

[0003] In recent years, so-called "smart" pneumatic tires have emerged, becoming an important component of modern vehicles by providing information about the type of pneumatic tire installed, its condition, and environmental conditions. These "smart" pneumatic tires are equipped with RFID ("Radio Frequency Identification") tags, which allow for the remote transmission of information such as tire identification, characteristics, and history.

[0004] When RFID tags are applied (bonded) to the inner surface (composed of the liner) of a raw pneumatic tire before vulcanization, defects may be observed at a certain frequency within the liner at the RFID tag location. In particular, at the end of vulcanization of the pneumatic tire, the liner may have detachment, breakage (cracks), or voids (i.e., lack of rubber) at the RFID tag location. Summary of the Invention

[0005] The object of the present invention is to provide a method for producing pneumatic tires equipped with electronic devices that does not have the disadvantages described above (i.e., there is no risk of liner detachment or rupture near the area where the electronic devices have been applied), and is easy and economical to produce at the same time.

[0006] According to the present invention, a method for producing a tire equipped with electronic devices is provided, as set forth in the appended claims.

[0007] The claims describe preferred embodiments of the invention, which form part of this specification. Attached Figure Description

[0008] The invention will now be described with reference to the accompanying drawings, which illustrate exemplary, non-limiting embodiments, in which:

[0009] • Figure 1 It is a schematic cross-sectional view of an inflatable tire equipped with electronic devices;

[0010] • Figure 2 and Figure 3 They are respectively suitable for accommodating Figure 1 Perspective and cross-sectional views of the rubber support components of the electronic device; and

[0011] • Figure 4 yes Figure 1 A schematic diagram of a raw pneumatic tire before the vulcanization process. Detailed Implementation

[0012] exist Figure 1 In the accompanying drawing, reference numeral 1 generally indicates an inflatable tire 1 comprising an annular carcass 2, which is partially folded over itself and thus has two lateral flaps (i.e., two layers stacked on top of each other and collectively referred to as "curls"). Two annular bead layers 3 are disposed on opposite sides of the carcass 2, with each of these two annular bead layers being surrounded by the carcass 2. The carcass 2 supports an annular tread 4 by the insertion of tread belt layers 5. Arranged within the carcass 2 is an airtight liner 6, which forms the lining and functions to retain air within the tire 1 to maintain the same inflation pressure of the tire 1 over time. The carcass 2 supports a pair of sidewalls 7, each of which connects a bead 3 to the tread 4.

[0013] The pneumatic tire 1 is equipped with an electronic device 8 that can transmit information related to the pneumatic tire 1 to an external control unit (located outside the pneumatic tire 1) without wires (i.e., by means of electromagnetic signals). The electronic device 8 can only store information related to the pneumatic tire 1 (such as a unique identification code), which can be read (and possibly modified) by means of wireless communication. This type of electronic device 8 is commercially known as RFID (“Radio Frequency Identification”) or “smart tag”.

[0014] like Figure 2 and Figure 3 As shown, the electronic device 8 includes an electronic circuit 9 (i.e., a microchip) with 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 electronic device 8 is a transponder). The electronic device 8 is inserted into a rubber support (sleeve) 11, which consists of two rubber strips 12 and 13, which are stacked and pressed against each other (capturing the electronic device 8 between them). According to different and equivalent embodiments (not shown), a single rubber strip 12 or 13 is provided on the opposite side of the liner 6 (i.e., one of the two rubber strips 12 and 13 is replaced by the liner 6).

[0015] like Figure 1 As shown, the electronic device 8 is disposed on the sidewall 7 of the pneumatic tire 1; according to other embodiments (not shown), the electronic device 8 may be disposed on other parts of the pneumatic tire 1 other than the sidewall 7 (such as the tread 4).

[0016] like Figure 1As shown, the rubber support 9 of the electronic device 8 is fixed (bonded) to the liner 6, that is, it is applied to the inner surface of the pneumatic tire 1 (more precisely, radially inward relative to the tread 4 and axially inward relative to the sidewall 7), which is composed of the inner surface of the liner 6 (exposed to air) (therefore, the rubber support 9 of the electronic device 8 is in direct contact with the liner 6). In other words, the electronic device 8 is on the outside of the pneumatic tire 1, that is, it is not integrated inside the pneumatic tire 1, and is applied (fixed, attached) to the inner (and in the view) surface of the liner 6, that is, the surface of the liner 6 that is outside the pneumatic tire 1 and therefore in direct contact with the air inside the pneumatic tire 1, and therefore the electronic device 8 is applied (fixed, attached) to the innermost free surface of the pneumatic tire 1.

[0017] The uncured components of the pneumatic tire 1 (carcass 2, tread belt layer 5, tread 4, inner liner 6, etc.) overlap each other to form a flat strip, which is then wound (in the assembly drum of the construction machinery) to form a cylinder, which is then deformed to take on a final annular shape. Specifically, the strip wound in the annular piece connects to itself, thus forming multiple joints (each component of the pneumatic tire 1 joins at different locations to avoid overlapping joints and thus avoid large discontinuities at a single point). The raw pneumatic tire 1 is then subjected to a vulcanization process in a suitable vulcanization mold.

[0018] like Figure 4 As shown, after the rubber support 11 of the electronic device 8 is applied (bonded, fixed) to the inner surface of the liner 6 and before the vulcanization process begins, a liquid release product P (lubricant) is applied (sprayed) to the interior of the pneumatic tire 1. This release product P prevents the rubber of the liner 6 from adhering (vulcanizing) to the air chamber of the vulcanization mold, which is inflated inside the pneumatic tire 1 to apply the necessary mechanical pressure. For example, the release product P (lubricant) can be silicone-based or mica-based.

[0019] In order to minimize the presence of defects (detachment or breakage) in the liner 6 within the area of ​​the rubber support 11 to which the electronic device 8 has been applied, without significantly impairing the success of the vulcanization process (i.e., without risking damage to the liner 6 of the pneumatic tire 1 or the air chamber of the vulcanization mold when the vulcanized pneumatic tire 1 is removed from the vulcanization mold), it is necessary that the amount of deposited release product P is within 5 mg / cm³. 2 With 30mg / cm 2 Between (and preferably equal to 15 mg / cm) 2 Meanwhile, the total thickness of the rubber support 11 of the electronic device 8 is between 0.5 mm and 1.5 mm (and preferably between 0.8 mm and 1.2 mm).

[0020] Importantly, it was observed that a certain amount of release agent P must be included to reduce the risk of detachment and breakage (cracks) of the liner 6. At the same time, the amount of release agent P must not be too small to ensure optimal removal of the vulcanized pneumatic tire 1 from the vulcanizing mold and to reduce the risk of voids (i.e., lack of rubber) within the liner 6 (the presence of release agent P improves the surface rubber flow during the vulcanization process, thereby preventing the formation of voids in the liner 6).

[0021] Furthermore, in order to minimize the presence of defects (detachment or breakage) in the area of ​​the rubber support 11 to which the electronic device 8 has been applied without significantly affecting the success of the vulcanization process, it is useful to minimize the total length L of the rubber support 11 of the electronic device 8 (i.e., Figure 2 The maximum dimension shown is between 40 mm and 100 mm (and preferably equal to 70 mm).

[0022] The embodiments described herein may be combined without departing from the scope of protection of this invention.

[0023] The production method of the pneumatic tire 1 described above has many advantages.

[0024] First, the production method of the pneumatic tire 1 described above enables the minimization of defects in the liner 6 at the rubber support 11 of the electronic device 8 without any difficulties related to removing the vulcanized pneumatic tire 1 from the vulcanizing mold.

[0025] Furthermore, the production method of the pneumatic tire 1 described above is particularly simple and economical to implement because it does not require the addition of any additional parts, but only requires attention to the manufacture of the rubber support 11 for the electronic device 8 and the deposition of the demolded product P before the vulcanization process.

[0026] List of reference numerals in the attached figures

[0027] 1 pneumatic tire

[0028] 2-fetal body

[0029] 3-Tire Bead

[0030] 4-tread

[0031] 5-Tread Belt Layer

[0032] 6 Lining

[0033] 7 sidewalls

[0034] 8 electronic devices

[0035] 9 Electronic Circuits

[0036] 10-line antenna

[0037] 11 Supporting components

[0038] 12 rubber strips

[0039] 13 Rubber Strip

[0040] P Demolding Products

[0041] L length

Claims

1. A method for producing a pneumatic tire (1), the method comprising the following steps: Manufacture a raw pneumatic tire (1) with an inner liner (6), the inner liner forming an inner lining and having the function of retaining air inside the pneumatic tire (1). An electronic device (8) inserted into a rubber support (11) is applied to the inner surface of the liner (6), which forms the innermost free surface of the pneumatic tire (1); The demolded product (P) is applied to the inner surface of the liner (6) of the raw pneumatic tire (1) for subsequent vulcanization process; as well as The raw pneumatic tire (1) is subjected to the vulcanization process; The production method is characterized by: The amount of deposited release product (P) is 5 mg / cm³. 2 With 30mg / cm 2 Between; and The total thickness of the rubber support (11) of the electronic device (8) is between 0.5 mm and 1.5 mm.

2. The production method according to claim 1, wherein the amount of the deposited release product (P) is 5 mg / cm³. 2 With 15mg / cm 2 between.

3. The production method according to claim 1, wherein the amount of the deposited release product (P) is equal to 15 mg / cm³. 2 .

4. The production method according to claim 1, 2 or 3, wherein the total thickness of the rubber support (11) of the electronic device (8) is between 0.8 mm and 1.2 mm.

5. The production method according to claim 1, 2 or 3, wherein the total thickness of the rubber support (11) of the electronic device (8) is equal to 1.0 mm.

6. The production method according to any one of claims 1 to 5, wherein the total length (L) of the rubber support (11) of the electronic device (8) is between 40 mm and 100 mm.

7. The production method according to any one of claims 1 to 5, wherein the total length (L) of the rubber support (11) of the electronic device (8) is equal to 70 mm.

8. The production method according to any one of claims 1 to 7, wherein the rubber support (11) of the electronic device (8) is composed of two rubber strips (12, 13) which are stacked and pressed against each other to capture the electronic device (8) between the two rubber strips.

9. The production method according to any one of claims 1 to 8, wherein the demolded product (P) is based on silicone or mica.

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