Classifications

• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B60—VEHICLES IN GENERAL
  • B60C—VEHICLE TYRES; TYRE INFLATION; TYRE CHANGING; CONNECTING VALVES TO INFLATABLE ELASTIC BODIES IN GENERAL; DEVICES OR ARRANGEMENTS RELATED TO TYRES
  • B60C11/00—Tyre tread bands; Tread patterns; Anti-skid inserts
  • B60C11/24—Wear-indicating arrangements

Definitions

• the present invention relates to a tire whose top comprises a tread provided with grooves and wear indicators.
• the wear indicator makes it possible to evaluate, on a basis of a reliable reference, the state of wear of the tires.
• This indicator is typically arranged in the grooves of the tires.
• the wear indicator is installed at the bottom of the grooves and is generally in rectangular form. It must be visible not only for the user, but also for third parties, for example in order to make it possible to check the compliance of the wear indicators with the legislation. It is therefore important to have effective and reliable visual cues to locate the wear indicators quickly and easily.
• the wear indicators of certain passenger car tires, particularly the models whose chassis is lowered are less visible insofar as body elements cover the upper part of the tires. In this situation, the wear indicator becomes less visible. The user can then identify the location of the wear indicator by referring to a marker located in the shoulder zone.
• Such a marker can be constituted by the well-known symbol "TWI” (meaning in English “Tire Wear Indicator”, or in French: indicator of wear indicator), or any other symbol easily recognizable by users.
• TWI meaning in English “Tire Wear Indicator”, or in French: indicator of wear indicator
• the grooves of the tread are completely covered with textures absorbing light, making the location of the wear indicator difficult or sometimes very difficult.
• patent application US6866076 discloses a tire intended to reduce the resistance to the flow of a fluid in the grooves.
• the tire has textures at the bottom of the grooves.
• the grooves of the tire are covered with small grooves or small ribs having a fixed depth in a range of 0.01 to 0.5 millimeters.
• the resistance to the flow of water in the groove is reduced.
• the wear indicator disposed among the grooves, is not very visible.
• the presence of the grooves near the wear indicators can make it difficult to control the height of the wear indicators.
• the grooves are obstacles that can affect the proper positioning of a measuring tool such as a slider, a micrometer, or caliper, which can cause inaccurate measurements.
• the invention provides different technical means.
• a first object of the invention is to provide a tire arranged to facilitate the identification or location of the wear indicators of the tread.
• Another object of the invention is to facilitate the verification of conformity of the wear indicators with the legal requirements.
• the invention provides a tire comprising a tread, the tire comprising at least one groove having a groove bottom, at least one wear indicator disposed in the groove, the wear indicator comprising a contact face intended to come into contact with a roadway when the tire reaches a limit wear level, the contact face of the wear indicator comprising a texture integral with this contact face, said texture contrasts with the bottom of the groove.
• the textured surfaces of the wear indicators absorb the light.
• the smoother surfaces of the grooves allow a better reflection of the light. This creates a contrast between the two surfaces and makes more visible wear indicator (s). The user can thus identify or locate the wear indicators of his tires with greater ease, making tire wear control less tedious.
• the tread reaches a limit wear level, the texture of the contact surface of the wear indicator is abraded by the roadway. The wear indicator becomes less visible in the groove, which can help alert the user to the need to change his tire.
• the texture has a brightness called first brightness (L * 1)
• the groove bottom has a brightness called second brightness (L * 2)
• the difference in brightness between the brightness (L * 1) and the brightness (L * 2) being at least 5 units (of brightness on a scale varying from 0 to 100.
• the first brightness (of the texture) is between 5 and 18 units, preferably between 8 and 16 units.
• the values tend towards black, so as to absorb the incident light well.
• the second brightness (of the groove bottom) is between 20 and 35 units.
• the values tend towards the white, so as to reflect the incident light well.
• the wear indicator comprises at least one side face connecting the contact face of the wear indicator to said bottom, said side face being provided with said texture. The textured side face helps to improve the visibility of the wear indicator in the groove.
• rubber material is meant a diene elastomer, that is to say in known manner an elastomer derived from at least in part (that is to say homopolymer or copolymer) of diene monomers. (monomers carrying two carbon-carbon double bonds, conjugated or not).
• tread of a tire is meant a quantity of rubber material delimited by lateral surfaces and by two main surfaces, one of which, called a tread surface, is intended to come into contact with a road surface. when the tire is rolling.
• sidewall of a tire means a side surface of the tire disposed between the tread of the tire and a bead of the tire.
• Textture means an organized arrangement of a plurality of elements, all or part of the elements of the arrangement being the repetition of the same basic element, for example, a strand or a lamella.
• strand is meant a filamentary element whose height is at least equal to 2 times the diameter of a disc of the same surface as the average section of the strand.
• laamellae is meant elongate strands having a length at least equal to twice their height.
• luminance is meant the parameter that characterizes a surface to reflect more or less light.
• the luminosity is expressed on a scale from 0 to 100 according to the colorimetric model L * a * b * established by the CIE (International Commission on Illumination) in 1976.
• the value 100 represents white or total reflection; the value 0, black or total absorption.
• a * and b * are chromaticity coordinates.
• the color model L * a * b * also defines a chromaticity diagram.
• a * and b * indicate the direction of the colors: + a * goes to red, -a * to green, + b * to yellow, and -b * to blue.
• the center of the diagram is achromatic. As the values a * and b * increase, and as we move away from the center of the diagram, the saturation increases. DESCRIPTION OF THE FIGURES
• FIG 1 is a partial view of a tread of a tire according to the invention.
• FIG. 2 is a sectional view of an exemplary wear indicator according to the invention.
• FIG. 3 is a sectional view of an alternative embodiment of the wear indicator of Figure 2;
• P10-3562enrep oa - Figure 4 shows a portion of the texture of the wear indicator according to a first embodiment wherein the texture has protruding elements in the form of strands;
• FIG. 5 shows a portion of the texture of the wear indicator according to a second embodiment in which the texture has lamellar protruding elements
• FIG. 6 shows a portion of the texture of the wear indicator, according to a third embodiment wherein the texture has parallelepiped shaped protruding elements
• FIG. 7 shows a portion of the texture of the wear indicator, according to a fourth embodiment wherein the texture has protruding elements whose shapes and distances between protruding elements are variable;
• FIG. 8 shows a portion of the texture of the wear indicator, according to a fifth embodiment wherein the texture has recessed elements conical in this example
• FIG. 9 represents an enlarged view of a cavity of a hollow element of the texture of FIG. 8.
• FIG. 1 is a schematic representation of a portion of a tread 8 of a tire 1.
• the tread 8 provides a ground contact surface consisting of peaks 9 of sculptures.
• the tread pattern of tire 1 form grooves 2, or furrows.
• the grooves 2 serve as a housing for positioning the wear indicators 3.
• the grooves 2 can also be arranged in different ways to meet specific functions. In the example illustrated, the grooves 2 are circumferential.
• the wear indicators 3 are provided with textures 4. Such a coating has many functional and visual advantages.
• the wear indicators 3, in particular the contact faces 7 of the wear indicators are advantageously provided with textures, and
• P10-3562enrep oa have a surface producing a contrast in brightness with the adjacent surface of the non-textured grooves.
• the contrast effect between the bottom of the grooves and the wear indicators 3 makes them visible, thus facilitating their location.
• Such a feature is particularly advantageous when the tread 8 is in a context where visibility is restricted.
• the wear indicator 3 comprises a contact face (or functional part) 7 provided with a texture 4.
• the wear indicator 3 is arranged in a groove 2 devoid of the texture 4. The absence of texture in the groove 2 makes it possible to create an accentuated contrast compared to the textured wear indicator 3.
• a wear indicator 3 may include other textured surfaces, such as a side face 6.
• Figure 3 illustrates such an embodiment.
• the integration of textured wear indicators 3 in grooves 2 untextured has the effect of enhancing the visibility of wear indicators 3 by contrast effects, including brightness.
• the wear indicators 3 are thus better visible.
• the texture of the wear indicator may protrude from the side face of the wear indicator in the bottom of the groove, over a length of between 3 and 10 mm.
• contrast effect comes from the fact that the brightness of the zones provided with textures is lower than that of the zones devoid of textures.
• Various arrangements or configurations of textures 4 make it possible to produce such an effect, as described below, in relation to FIGS. 4 to 9.
• the device for measuring the appropriate brightness is a CM 700D spectro-colorimeter of the brand KON ICA-MINOLTA, (registered trademark). This device is suitable for measuring:
• P10-3562enrep oa a component a * that defines a first shade of color between red and green;
• a component b * that defines a second shade of color between yellow and blue.
• Figures 4 to 9 illustrate examples of textures 4 that can be arranged on the wear indicator 3 according to the invention.
• FIG. 4 illustrates an embodiment in which the texture comprises a plurality of strands 1 1.
• the strands 11 are distributed in the texture according to a density of at least one strand per mm 2 , each strand having an average section S of between 0.0005 mm 2 and 1 mm 2 . It is noted that the average section of each strand corresponds to the average of sections S measured at regular intervals from the base of the strand.
• the strands have a generally conical shape with a decreasing section in the Hb height of these strands.
• FIG. 5 illustrates an embodiment in which the texture 4 comprises a plurality of blades 12 parallel to each other, the pitch of the blades 12 in the texture being at most equal to 0.5 mm, each blade 12 having a width average between 0.02 mm and 0.5 mm. Note that the average width corresponds to the average width I measured at regular intervals in the height Hl of the blade, the height of each blade being between 0.05 and 0.5 mm.
• the texture comprises a combination of strands 1 1 and / or blades 12.
• the blades 12 of Figure 5 may be discontinuous. They have a flat part between them. In addition, they may have section differences between them. In addition, the blades may have curvatures or angles, especially in their length. They can also be of variable length.
• the textures have a parallelepipedal section 13 of side C between 0.05 mm and 0.5 mm, with a height Hp of between 0.05 mm and 0.5 mm, the distance Dp between two adjacent cavities in the texture being between 0.05 mm and 0.5 mm.
• the section of the textures may be circular, polygonal (for example hexagonal). With square or polygonal structures, it is possible to more easily organize the elements relative to each other so as to limit the area of the intermediate zones between the elements.
• the elements 14 have shapes and variable distances between them. This variant makes the details of the texture 4 less visible.
• FIG. 8 illustrates a texture 4 according to another non-limiting embodiment.
• the texture is formed by a plurality of cavities 16.
• the cavities 16 are here in the form of cones which extend into the depth of the surface and open out onto this surface forming circular openings.
• the cavities 16 thus have a section which decreases in depth.
• the openings 15 of the cavities 16 do not touch.
• the openings 15 are separated by intermediate zones 17.
• the openings 15 are regularly distributed so that the distance d between each opening 15 is generally similar.
• FIG. 9 is an enlarged view of the texture of FIG. 8. All or part of the cavities here have at least one wall 18
• P10-3562enrep oa which, in a sectional view, forms an angle ⁇ between 10 ° and 60 ° with respect to a direction Z perpendicular to the texture 4.

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• Engineering & Computer Science (AREA)
• Mechanical Engineering (AREA)
• Tires In General (AREA)

Applications Claiming Priority (2)

Publications (1)

Family

ID=53491584

Family Applications (1)

Country Status (3)

Family Cites Families (7)

• 2015
  • 2015-03-30 FR FR1500629A patent/FR3034359B1/fr not_active Expired - Fee Related
• 2016
  • 2016-03-25 EP EP16714505.1A patent/EP3277526A1/de not_active Withdrawn
  • 2016-03-25 WO PCT/FR2016/050684 patent/WO2016156719A1/fr active Application Filing

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