WO2018011760A1

WO2018011760A1 - Tyre having a reference layer

Info

Publication number: WO2018011760A1
Application number: PCT/IB2017/054268
Authority: WO
Inventors: José Merino Lopez
Original assignee: Compagnie Générale Des Établissements Michelin
Priority date: 2016-07-15
Filing date: 2017-07-14
Publication date: 2018-01-18
Also published as: FR3053928A1; FR3053928B1

Abstract

Disclosed is a tire (1) comprising at least one carcass reinforcement ply (2) that consists of a plurality of reinforcing cords (7) embedded between a first (8) and a second (9) layer of a carcass elastomer composition, the second layer (9) being located axially outside the first layer (8); the carcass reinforcement ply (2) is arranged between an inner layer (10) and an outer layer (11) of an elastomer composition; a layer of an elastomer composition having a color (12) other than black is alternatively disposed: - in lieu of the skim coat rubber (8, 9) embedding the reinforcing cords (7) of the carcass ply; or - between the elastomer composition (10) forming the sidewall and the second layer (9) of the elastomer composition of the carcass ply; or - in lieu of the second layer (9) of the elastomer composition of the carcass ply.

Description

PNEUMATIC WITH REPERAGE LAYER

TECHNICAL FIELD OF THE INVENTION [0001] The present invention relates to a tire for a wheel assembly comprising a rim and a tire, said tire comprising at least one carcass reinforcement surmounted radially on the outside of a tread, the armature carcass assembly consisting of a plurality of reinforcement yarns coated between two layers of carcass elastomer composition, said carcass reinforcement being arranged between an inner layer and an outer layer of elastomeric composition. It relates more particularly to a tire comprising a tracking means enabling a user to easily identify a damage caused to the tire.

STATE OF THE PRIOR ART

[0002] Tires for vehicles of all kinds are very often the object of damage due to shocks and / or rubbing against various objects such as sidewalks, fencing bases or other protective strips along the roads. , potholes and other defects or damage to a road, rocks or stones present on the roadway, or any object foreign to the road inadvertently present on the road because of various circumstances such as a fall of a truck or any other type of vehicle.

[0003] Such damage is so common that most drivers pay little attention to it. However, some damage is deeper or larger than others and can sometimes affect the life or integrity of a tire. Known tires, however, do not have means for distinguishing unimportant micro-damage larger damage requiring intervention. US 3594248 describes a tire comprising a color layer disposed in the outer zone of at least one of the sidewalls. This layer of color is intended only for aesthetic purposes.

To overcome these disadvantages, the invention provides different technical means.

SUMMARY OF THE INVENTION [0007] Firstly, a first object of the invention is to provide a tire comprising a means or device enabling the user to be easily informed in the event of damage to a tire.

Another object of the invention is to provide a tire with means for producing an alert or a visual warning in case of damage, without having to perform manipulation or specific technical operation.

Yet another object of the invention is to provide a tire provided with means for a user to reliably and reliably differentiate a trivial damage, not requiring specific intervention, and more significant damage, likely to affect the life of the tire, and requiring any control or maintenance intervention. To do this, the invention provides a tire for a wheel assembly comprising a rim and a tire, said tire comprising at least one carcass reinforcement layer radially surmounted externally of a crown ply itself radially. inside a tread, said tread being connected to two beads via two sidewalls made of elastomer composition, said beads being intended to come into contact with the rim, each bead having at least one circumferential reinforcing element, the carcass reinforcement layer being constituted by a plurality of reinforcement threads embedded between a first and a second layer of carcass elastomer composition, called a calendering rubber, for forming the carcass ply, said second calender gum layer being disposed axially outside said first calender layer, said carcass reinforcement layer being arranged between an inner layer and an outer layer of elastomer composition, a layer of elastomer composition of a color different from black, also called color gum, being disposed as desired:

in place of the calendering rubber coating the reinforcements of the carcass ply, or

between the outer layer constituting the flank and the second layer of elastomer composition of said carcass ply or

in place of the second layer of elastomer composition of said carcass ply.

The marking area makes it easy and quick to make visible any damage or accidental wear caused to the tire. In addition, the locating area is located in close proximity to structurally important components for the tire. Thus, any superficial or shallow damage (ie the vast majority of damage due to current shocks) does not release the tracking area. The user is therefore warned only when the situation is likely to require a maintenance intervention, repair or even change of tire.

According to an advantageous embodiment, the color gum comprises titanium oxide, kaolin, chalk or a mixture thereof.

Alternatively, the color gum may comprise TPE, such as SIS, SBS. According to a first exemplary embodiment, the color gum is in the form of a layer covering a plurality of reinforcements. This embodiment is particularly advantageous because of the industrialization facilities offered. The distinct color layer is advantageously implemented during the manufacturing operations of the reinforcing plies, making the process simple and inexpensive. The traditional manufacturing method is not questioned.

According to another embodiment, the color gum is in the form of individual coating of each of the reinforcing cables. This embodiment makes it possible to locate the registration area very precisely and locally in contact with the carcass structure wires. This frees the registration area only when damage may affect the integrity of a reinforcing wire, thus avoiding generating cases of unnecessary alert for other situations. According to another embodiment, the color rubber is disposed on a single sidewall of the tire, preferably the side intended to be positioned on the outside of the vehicle. This arrangement makes it possible to target the locating zone (s) on the areas of the tire subject to shocks against sidewalks and other types of very frequent shocks.

According to another embodiment, the color gum is disposed in the crown ply.

Still alternatively, the registration area is provided under the main grooves of the tread to detect aggression of the first layer of reinforcements, the one closest to the outer surface.

DESCRIPTION OF THE FIGURES [0019] All the details of embodiment are given in the description which follows, supplemented by FIGS. 1 to 6, presented solely for purposes of non-limiting examples, and in which: Figure 1 is a schematic representation of a section of a portion of a sidewall of a first example of a tire according to the invention;

FIGS. 2A and 2B are diagrammatic representations of a section of a portion of a sidewall of a second example of a tire according to the invention;

- Figure 3 is a schematic representation of a section of a portion of a sidewall of a third example of a tire according to the invention;

Figures 4 and 5 illustrate examples of schematic sections of tires according to the invention provided with a registration layer in the example of Figure 4 and two registration layers in the example of Figure 5;

- Figure 6 is a schematic representation of a section of a portion of a sidewall of a fourth example of a tire according to the invention.

DETAILED DESCRIPTION OF THE INVENTION

"Radial direction" means a direction which is perpendicular to the axis of rotation of the tire (this direction corresponds to the direction of the thickness of the tread).

"Axial direction" means a direction parallel to the axis of rotation of the tire.

By "circumferential direction" at a point of a meridian plane means the direction which is tangential to the circle centered on the axis of rotation and contained in a circumferential plane. This direction is perpendicular to both the axial direction and the radial direction.

In what follows, the expressions "radially inner to" and "radially outside to" respectively mean "closer to the axis of rotation of the tire, in the radial direction, that" and "further from the axis of rotation of the tire, in the radial direction, that ».

The expressions "axially inner to" and "axially outside to" mean respectively "closer to the equatorial plane, in the axial direction, than" and "further from the equatorial plane, in the axial direction, than".

Figures 4 and 5 illustrate examples of tires 1 according to the invention. The tire 1 comprises at least one carcass reinforcement 2 extending from one bead 5 to the other, passing through a crown area surmounted radially outwardly of a tread 3. This tread 3 is connected to the beads 5 via the flanks 4. Circumferential reinforcing elements 6, often referred to as the bead wire, are provided in each of the beads 5. The carcass reinforcement cooperates with each of the rods to ensure the maintenance of all. As shown in Figures 1, 2A, 2B and 3, the carcass reinforcement 2 and consisting of a plurality of reinforcement son 7 embedded between a first layer 8 of carcass elastomer composition and a second layer 9 of elastomeric carcass composition. An outer layer 1 1 of elastomeric composition covers the outer side of the carcass reinforcement 2. An inner layer 10 of elastomeric composition covers the inner side of the carcass reinforcement.

In the embodiments of Figures 1 to 3, the tire 1 comprises at least one color layer 12 different from the black, provided between the outer layer 1 1 of elastomer composition and son 7 reinforcement. This color layer 12 different from black is made with an elastomeric composition of color distinct from the outer layer 11 which is preferably black. In the embodiment of Figure 1, the color layer 12 different from black takes the form of a separate layer, arranged between the carcass reinforcement 2 and the outer layer 1 1. Alternatively, an additional layer is also provided between the inner layer 10 and the carcass reinforcement.

In the embodiment of Figure 2A, the color layer 12 different from the black is integrated with the layer 9 of carcass elastomer composition. This layer then fulfills a dual function, namely a structural function, and a function of identifying or identifying any damage. This variant is also illustrated in FIG. 2B. Alternatively, both sides of the reinforcing son 7 of the carcass reinforcement are provided with a separate layer. This variant is illustrated in the example of FIG.

With this arrangement, in case of damage to the outer layer 1 1, the color layer 12 becomes visible and the user is informed of the damage caused. In case of surface damage, only on the surface of the outer layer 1 1, the color layer 12 serving as a registration area is not released or made visible. This minor non-structural damage is therefore not reported to the user. The user is not alerted inadvertently every time a shock against a sidewalk or other causes a superficial damage.

FIG. 6 illustrates yet another embodiment in which each of the reinforcing threads 7 of the carcass reinforcement 2 is coated with a thin layer of elastomer composition forming an individual coating 13 of a color that is distinct from the black. This embodiment, with multiple locating areas (as many zones as reinforcement son) very localized, allows to target the damage that is revealed. In addition, this approach avoids nuisance alerts due to superficial damage. Another embodiment provides a dual tracking zone. In this embodiment, a color layer 12 distinct from black as previously described in relation to FIGS. 1, 2A, 2B and 3, is provided with a first color. A plurality of individual color coatings 13 distinct from black, as previously described in connection with Figure 6 is also provided, with a second color, distinct from the first. This hybrid embodiment makes it possible to generate two levels of alert or warning. A first alert level is given when a damage releases a portion of the color layer 12. A second, more critical alert level is given when a damage releases one or more individual coatings 13. This embodiment is particularly suitable for tires intended for use in severe or aggressive environments such as construction sites or mines, and makes it possible to know the real state of the tires and to take the measures required at the appropriate time. It is also well suited for tires intended for two-wheeled vehicles where the safety requirements are critical for the user.

As a variant of the various embodiments previously described, the color layer 12 distinct from the black is located only at the sidewalls of the tire. For example, a color layer 12 is advantageously provided at the sidewall of the tire intended to be on the outside of the vehicle (the visible sidewall when the tire is mounted on the vehicle). It is in fact at the level of the flanks, and more particularly in the zone of the equator (zone where the tire is of greater width) that the risks of damage are the most important since the flanks do not have the multiple layers of protection, unlike the summit area, protected by tread and top reinforcements. This variant can be implemented in relation to one or more registration layers 12 as previously described, or in relation to individual coatings 13 as described in relation to FIG. 6, or in relation to the hybrid mode involving the once one or more layers 12 and coatings 13 of different colors, as previously described. At the top, the area under the furrows is more exposed and may be subject to this type of protection. Reference numbers used in Pneumatic figures

Layer of carcass reinforcement

Tread

Flank

bead

Circumferential reinforcement

Reinforced carcass thread

First layer of elastomer carcass composition

Second layer of carcass elastomer composition

Internal layer of elastomer composition

Outer layer of elastomer composition

Color layer different from black

Individual coating of reinforcement threads of a color distinct from black

Claims

1. Pneumatic tire (1) for a wheel assembly comprising a rim and a tire, said tire (1) comprising at least one carcass reinforcement layer (2) surmounted radially on the outside of a crown ply itself radially to the interior of a tread (3), said tread (3) being connected to two beads (5) via two sidewalls (4) made of elastomer composition, said beads (5) being intended to enter in contact with the rim, each bead (5) comprising at least one circumferential reinforcing element (6), the carcass reinforcement layer (2) consisting of a plurality of reinforcing threads (7) embedded between a first

(8) and a second (9) layer of carcass elastomer composition, called a calendering rubber, for forming the carcass ply, said second layer

(9) of calendering gum being arranged axially outside said first layer (8) for calendering, said layer of carcass reinforcement (2) being arranged between an inner layer (10) and an outer layer (1 1) of elastomer composition, characterized in that a layer of elastomeric composition of color (12) other than black, also called color gum, is disposed as desired:

in place of the calendering rubber coating the reinforcements (7) of the carcass ply, or

between the outer layer (1 1) forming the sidewall and the second layer (9) of elastomer composition of said carcass ply or

in place of the second layer (9) of elastomer composition of said carcass ply.

2. A tire (1) according to claim 1, characterized in that the color gum (12) comprises titanium oxide, kaolin, chalk or a mixture thereof.

Tire (1) according to claim 1, characterized in that the color gum (12) comprises TPE, such as SIS, SBS.

4. Tire (1) according to any one of claims 1 to 3, characterized in that the color gum (12) is in the form of a layer covering a plurality of reinforcements (7).

5. A tire according to claim 1, characterized in that the color gum (12) is in the form of individual coating (13) of each of the cables (7) reinforcements.

Tire (1) according to one of Claims 1 to 5, characterized in that the colored rubber (12) is arranged on a single sidewall (4) of the tire.

7. A tire (1) according to claim 6, characterized in that the sidewall is the flank intended to be positioned on the outside of the vehicle.

8. Pneumatic tire (1) according to any one of claims 1 to 5, characterized in that the colored gum (12) is disposed in the crown ply.