Tire Provided With An Electronic Device

Abstract

Tire of maximum width LT comprising a tread (1) asymmetric about the equatorial plane, one of its sides of which is intended to be positioned on the outboard side of the vehicle, a crown inner liner, radially furthest on the inside of the crown, and an electronic device with a sensor making for measuring at least one parameter. This electronic device is installed in the tire under the crown, radially on the inside of the inner liner of the crown, on the side of the tread that is intended to be positioned on the outboard side of the vehicle with respect to the equatorial plane and such that the axial distance from the centre of gravity of the electronic device to the equatorial plane is at least equal to 5% and at most equal to 25% of the maximum axial width of the tire LT.

Claims

1. A tire with a maximum axial width LT, adapted to be mounted on a mounting rim, comprising: two beads, adapted to come into contact with the mounting rim, a crown comprising a tread adapted to be in contact with the ground, two sidewalls connecting the crown to the beads, the tread, asymmetric about the equatorial plane, delimiting two axial edges of the tread, one of which edges is adapted to be positioned on the outboard side of a vehicle on which the mounting rim is fixed, an inner liner of the crown which is radially furthest on the inside of the crown, an electronic device, wherein the electronic device is installed in the tire under the crown, radially on the inside of the inner liner of the crown, on the side of the axial edge of the tread that is adapted to be positioned on the outboard side of the vehicle with respect to the equatorial plane.

2. The tire according to claim 1, wherein the electronic device comprises at least one measurement sensor making it possible to measure at least one parameter of the tire.

3. The tire according to claim 1, wherein the axial distance between the centre of gravity of the electronic device and the equatorial plane is at least equal to 5% of the maximum axial width of the tire LT.

4. The tire according to claim 1, wherein the axial distance between the centre of gravity of the electronic device and the equatorial plane is at most equal to 25% of the maximum axial width of the tire LT.

5. The tire according to claim 1, wherein the centre of gravity of the electronic device is situated radially in line with a circumferential groove in the tread.

6. The tire according to claim 1, wherein the centre of gravity of the electronic device is situated radially in line with a rib of the tread.

7. The tire according to claim 1, wherein the circumferential position of the electronic device is opposite the static out-of-balance of the tire.

8. The tire according to claim 1, wherein at least one balancing weight is positioned radially on the inside of the inner liner of the tire.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

[0032] The features and other advantages of the invention will be understood better with the aid of FIGS. 1 to 4, said figures not being drawn to scale but in a simplified manner so as to make it easier to understand the invention.

[0033] FIG. 1 depicts a tire according to the prior art,

[0034] FIG. 2 illustrates the terms inner edge and outer edge of a tread,

[0035] FIGS. 3 to 4 depict two embodiments of the invention.

DETAILED DESCRIPTION OF THE DRAWINGS

[0036] FIG. 1 depicts a tire viewed in meridian cross section provided with an electronic device 3 according to the prior art. The tire comprises a tread 1, an inner liner 2, radially on the inside of the tread and an electronic device 3, radially on the inside of the inner liner and the centre of gravity of which is in the equatorial plane, to within the positional accuracy.

[0037] FIG. 2 schematically depicts tires intended to be mounted on mounting rims of wheels of a vehicle 200 and having a predetermined direction of mounting on the vehicle. They comprise an outer axial edge 45 and an inner axial edge 46, the inner axial edge 46 being the edge intended to be mounted on the bodyshell side of the vehicle when the tire is mounted on the vehicle in the said predetermined direction of mounting, and the outer axial edge 45 being the opposite of that.

[0038] FIG. 3 shows a tire viewed in meridian section provided with an electronic device 3 according to the invention in which the centre of gravity of the electronic device 3 is situated on the side of the outboard axial edge 45 of the vehicle with respect to the equatorial plane and at a distance from the equatorial plane that is at least equal to 5% of the maximum axial width of the tire LT and at most equal to 25% of this width. In this figure, the centre of gravity of the electronic device 3 is situated radially in line with the circumferential groove 4 in the tread.

[0039] FIG. 4 shows a tire equipped with an electronic device 3 according to the invention and in which the centre of gravity of the electronic device 3 is situated in line with a rib 5 of the tread.

[0040] The inventors implemented the invention on an asymmetric tire of size 305/30ZR20 103Y, with a maximum axial width of 313 mm, tested with a camber angle of 2.5 so as to take account of the technical requirements of a vehicle for which it is specifically intended. The test consisted in running on a metal rolling road 8.5 m in circumference, at a set pressure of 3.2 bar and a set load of 587 daN. The tire was run at levels of increasing speed, lasting 20 minutes each, the speed increment being 10 km/h. The tires are classified according to the maximum speed achieved and the length of running at the last speed level achieved.

[0041] The tire without the electronic device reached the level of 370 km/h and ran at this speed for 11 minutes. As for the tire according to the prior art, namely equipped with the electronic device, a pressure sensor weighing 7 g, positioned according to the prior art and therefore installed in the tire in such a way that its centre of gravity is in the equatorial plane, to within the positioning tolerance of 1% of the maximum axial width, this tire achieved the speed level of 340 km/h and failed after running under these conditions for one minute. This result, when compared with that of the tire not fitted with the electronic device, demonstrates the drop in endurance performance at very high speed caused by the presence of the electronic device. This failure is connected with the 15 C. increase in crown temperature seen by numerical simulation in line with the sensor, this being at the same speed on the tire not equipped with an electronic device and on the tire equipped with the electronic device according to the prior art.

[0042] The inventors tested two embodiments of the invention. The first embodiment consisted in installing the electronic device at a distance from the equatorial plane of 16% of the maximum axial width, in line with a rib of the tread. In this case, the tire according to the invention achieved the speed level of 360 km/h and ran for 15 minutes at this level. This, when compared to the result of the tire equipped with the electronic device positioned in the equatorial plane, namely the maximum achieved level of 340 km/h, demonstrates the improvement in high-speed endurance of the tire equipped with the electronic device as described by the invention.

[0043] The second embodiment consisted in installing the electronic device at a distance from the equatorial plane of 7% of the maximum axial width, in line with a groove of the tread. In this case, the tire according to the invention achieved the speed level of 370 km/h and ran for 15 minutes at this level. The maximum crown temperature dropped by almost 15 C. This result, when compared to the result of the tire equipped with the electronic device positioned in the equatorial plane, namely the maximum achieved level of 340 km/h, shows the improvement in high-speed endurance of the tire equipped with the electronic device as described by the invention according to this second embodiment.