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
• • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
  • Y10—TECHNICAL SUBJECTS COVERED BY FORMER USPC
  • Y10T—TECHNICAL SUBJECTS COVERED BY FORMER US CLASSIFICATION
  • Y10T152/00—Resilient tires and wheels
  • Y10T152/10—Tires, resilient
  • Y10T152/10027—Tires, resilient with wear indicating feature

Definitions

• the present invention relates to a tire provided with sound wear indicators. It applies in particular, to be restricted to tires for vehicles of any type, tourism or trucks.
• Document FR 2 937 902 discloses a tire comprising, in addition to the aforementioned legal wear indicators, equally divided sound wear indicators constituted by sound cavities. Each cavity is delimited in part by two strips arranged at the bottom of a groove of the tire. Each cavity is shaped so as to be closed by the ground in a substantially watertight manner so as to temporarily trap air as it passes through the contact area of the tire with the ground. Under the effect of the deformation of the tire in the contact area, this air trapped in the cavity compresses and then suddenly relaxes at the exit of the contact area and therefore the cavity opens. This expansion of the air causes a specific noise that appears only when the tire is worn beyond a certain threshold. Thus, even if the driver does not regularly oblige to visually inspect the surface condition of his tires, he is informed of the excessive wear of his tires when, while driving, the specific noise is detected.
• the sound cavities because of the arrangement of the barrettes in the grooves, can degrade the performance of the tire with respect to a tire without such sound cavities, especially in terms of evacuation of water by the grooves and therefore adhesion, mainly because of the large number of strips used to delimit the different cavities. This degradation of the water evacuation performance is even greater than the wear of the tire is advanced.
• the design of the tire and its mold is complex, especially because of the large number of barrettes used to delimit the different cavities.
• a witness is located at the same position as an element of the sculpture such as an open cutout opening into the cavity defined by the two barrettes, T the cavity does not emit the expected noise, because it is not closed so as to trap air, and thus does not detect wear.
• a barette is located at the same position as a particular zone of the mold, such as the joint between two sectors, the barette is weakened mechanically by the numerous openings and closures of the mold during the many tire firing. . If, in addition, we want to respect the equi-distribution of the witnesses, it is then difficult, if not impossible, to conceive empirically a tire in which all the wear indicators satisfy these constraints of interaction with the elements of sculpture and of mold.
• the invention aims in particular to provide a tire with sound wear indicators having little influence on the performance and design of the tire.
• the subject of the invention is a tire comprising at least:
• the projections of first threshold are equi-distributed circumferentially on the tire.
• the inventors have discovered that the first threshold projections are sufficient to cause a characteristic noise during the rolling of the tire once the first wear threshold of the tire reaches.
• the inventors put forward the hypothesis that this noise is generated by at least two distinct physical phenomena having a synergistic effect.
• the noise is generated by the impact of the protrusion on the ground.
• an air plug is likely to form in the groove upstream of the projection because of the significant relative speed between the tire. tire and the air into which the tire enters. Air is thus trapped temporarily in a space between this cap and the projection during the passage of this space in the contact area of the tire with the ground. Under the effect of the deformation of the tire in the contact area, this air trapped in this space compresses and then slackens abruptly at the exit of the contact area when the tread leaves the contact with the ground at the same time. rear of the tire.
• each wear indicator consisting of a single projection and not two projections forming a cavity closed to air during its passage in the contact area of the tire with the ground, with an equal number of wear indicators, the number of projections disposed in the groove or grooves is divided by two. This limits the potential loss of performance generated by the projections. The adhesion performance of the tire is therefore relatively little impacted.
• the projections being arranged in the grooves, the noise emitted through the projections is amplified relative to sonic wear indicators that would be arranged elsewhere in the tread.
• the noise emitted is amplified by a horn formed by the tire and the ground once the sound wear indicator has passed the contact area.
• This amplification effect flag is maximum when the projections are preferably arranged axially in a central portion of the tread.
• the central portion of the tread means the region of the tread extending axially, that is to say parallel to the axis of rotation of the tire, over substantially half the width of this tread. rolling under the nominal conditions of load and pressure and centered relative to the central median plane of the tire.
• the noise emitted beyond the first wear threshold has remarkable frequency characteristics.
• the spectral analysis of the noise emitted beyond the wear threshold shows, in the frequency domain, a Dirac comb that can easily be identified among all the parasitic noises such as tire rolling noise. , the wind, the noise of the engine or the sound of the kinematic chain associated therewith. It will be possible to use a method for detecting the wear of the tire according to the invention as described in application PCT / FR2010 / 052584. Alternatively, other methods may be used.
• a processing unit and one or more detection microphones are used, connected to a processing unit able to detect noise among the rolling noise and to inform the driver of the wear of his tires.
• each projection is situated substantially at the same angular distance from the two projections which are adjacent to it, whether they are arranged in the same groove or not.
• the equi-distributed projections have two by two the same angular difference.
• this single projection is considered circumferentially equi-distributed. Indeed, in this case, the adjacent projections are formed by the projection itself.
• the protrusions of the tire according to the invention are distinguished from anti-chippings gum loaves intended to prevent the chippings to lodge in the grooves of tires for vehicle type heavyweight. Indeed, unlike these rubber bars, the projections of the tire according to the invention have as their main function a sound function and not an "anti-gravel" function.
• the number of sets of projections corresponding to a determined wear threshold is generally between 2 and 30.
• the tire according to the invention comprises patterns comprising no projection.
• the circumferential width of a gum protrusion is generally between 2 and 15 mm (millimeters), and preferably between 3 and 10 mm. These values are suitable for the generation of adequate rolling noise.
• the circumferential position of a projection may be considered to be that corresponding to the median position of its circumferential width.
• the projections are in rubber and molded with the rest of the tire.
• a wear threshold of the tire more advanced than the first wear threshold is a legal wear threshold.
• the first threshold protrusions make it possible to warn the driver in advance of the next attainment of the legal wear threshold.
• the tire comprises two protrusions of first circumferentially successive threshold arranged at the bottom of the same groove.
• the tire comprises two protrusions of first circumferentially successive threshold arranged at the bottom of different grooves.
• the tire comprises a set of first threshold projections arranged at the bottom of different grooves, each first threshold projection of the assembly being substantially axially aligned with each other first threshold projection of the assembly.
• the tire may comprise at least one protrusion of legal threshold per groove and preferably several protrusions of legal threshold per groove.
• the tire comprises a set of projections legal threshold arranged at the bottom of different grooves, each legal threshold projection of the assembly being substantially aligned axially with each other projection legal threshold of all.
• the tire comprises two legal threshold protrusions arranged at the bottom of different grooves and offset axially relative to each other.
• the projection or projections of the same threshold are equi-distributed circumferentially on the tire.
• the projections of this threshold behave as the first threshold projections.
• the noise emitted by the projections of this threshold therefore has, in the frequency domain, analogous to the noise generated by the first threshold projections, remarkable frequency characteristics.
• the spectral analysis of this noise shows, in the frequency domain, similar to the noise generated by the first threshold projections, a Dirac comb that can be easily identified.
• all the projections are equi-distributed circumferentially on the tire.
• the projections are arranged so that, irrespective of the wear of the tire, two circumferentially successive protrusions of the same groove and the groove delimit an open space to the air during the passage of the two projections in the groove. tire contact area with the ground.
• each circumferential groove has a predetermined depth and the height of each projection of each threshold is substantially equal to the difference between the predetermined depth of the groove and the wear threshold.
• the projection or projections extend partially transversely to the bottom of the furrow or grooves so that the tire comprises at least one fluidic passage channel between the or the projections and at least one wall delimiting the furrow (s). .
• the fluidic passage makes it possible to avoid, that beyond the most advanced threshold, the protrusions define a closed cavity during their passage in the contact area of the tire with the ground.
• Such a cavity because of the noise it would produce, would destroy the equi-distribution of the projections and modify the characteristics of the noise generated by the projections.
• the fluid passage improves the evacuation of water through the grooves and therefore the performance of the tire.
• one or all the projections may also extend transversely over the entire width of a circumferential groove, the distribution of the projections being preferably performed so as not to create sound cavity between two successive projections. It has indeed been found that the sound effect generated by a projection is significantly greater when this projection extends transversely over the entire width of a circumferential groove.
• the circumferential groove is closed by the ground at the level of the protrusion of rubber, which delimits an upstream space and a downstream space of this groove, without communication between them at the level of the gum protrusion. It is found that this significantly increases the sound effect.
• each projection for example of first threshold may comprise at least one cavity formed in the projection, the cavity being shaped so as, beyond the first threshold:
• the cavity does not extend to the bottom of the circumferential groove, the volume of this small cavity being typically significantly less than 250 mm 3 (cubic millimeters), for example less than 150 mm 3 .
• Such a cavity is sound.
• the noise it generates, although limited, is added to the noise generated by the projections and gives an amplified noise compared to a projection without a cavity.
• the cavity makes it possible to visually distinguish the first threshold projection from the legal wear indicator.
• each projection of a threshold is circumferentially separated from each projection of another threshold.
• each projection of a threshold is contiguous to a projection of another threshold, which has the advantage that these two projections do not define between them a closed cavity capable of disturbing the detection of the expected noise.
• a projection corresponding to a determined wear threshold is not contiguous to another projection, it is typically also a wear indicator for the higher wear thresholds.
• a projection is contiguous to another projection corresponding to a higher wear threshold, when the latter threshold of wear is reached, the two contiguous projections form a single projection, forming a witness of unique wear corresponding to this threshold (and not two juxtaposed witnesses).
• the tire comprises at most 12 protrusions, preferably at most 8 protrusions, each able to come into contact with the ground during their respective passage in the contact area of the tire with the ground at beyond a second wear threshold, more advanced than the first threshold.
• the tire comprises at most 4 first threshold protrusions and, preferably, at most 3 first threshold protrusions.
• FIG. 1 is a perspective view of a tire in a new state according to a first embodiment of the invention
• Figure 2A schematically illustrates a developed tread the tire of Figure 1;
• Figure 2B schematically illustrates a developed tread of a variant of the tread of Figure 2A;
• Figure 3 is a perspective view of the tire of Figure 1 in a worn state beyond a first predetermined radial wear threshold
• Figure 4 is a perspective view of the tire of Figure 1 in a worn state beyond a second predetermined radial wear threshold
• FIG. 5A is similar to FIG. 2 and illustrates a developed tread of a tire according to a second embodiment of the invention
• FIG. 5B schematically illustrates a developed tread of a variant of the band of FIG. 5A;
• Figure 6 is similar to Figure 2 and illustrate a developed tread of a tire according to a third embodiment of the invention.
• Figure 7 is a view similar to that of Figure 1 of a tire according to a fourth embodiment of the invention.
• Figure 8 is a top view of a tread of the tire of Figure 7;
• Figure 9 is a view similar to that of Figure 1 of a new tire according to a fifth embodiment of the invention.
• FIG. 10 is an axial sectional view in a plane passing through a groove of a tread of the tire of Figure 9 worn to a first wear threshold;
• Figure 11 is a view similar to that of Figure 1 of a new tire according to a sixth embodiment of the invention.
• FIG. 12 is an axial sectional view in a plane passing through a groove of a tread of the tire of Figure 11 worn to a first wear threshold.
• FIG. 1 a tire in the new state according to a first embodiment of the invention, designated by the general reference 10.
• the tire 10 is intended for a passenger vehicle.
• the tire 10 is substantially of revolution about an axis.
• the tire 10 comprises a tread 12 of shape substantially toroidal and whose outer surface is provided with sculptures 14.
• the tread 12 comprises two grooves 16 circumferential and parallel, hollowed on the surface of the tire, of predetermined depth H when the tire 10 is new.
• the depth H of these grooves 16 is of the order of 8 mm and their width is of the order of 10 mm.
• the tire comprises TUS sound wear indicators indicating a first wear threshold SS.
• Each audible wear indicator TUS consists of a protrusion of rubber 17, referred to as the first threshold protrusion, arranged transversely to the bottom of the groove 16 in which it is located and extending radially from the bottom of this groove 16.
• each projection 17 has a predetermined height h s substantially equal to the difference between the depth H of the grooves 16 and the threshold SS.
• the tire 10 comprises TUL wear indicators (the TUL designation, instead of TUS indicating a second wear threshold SL which corresponds to the legal wear threshold of the tire).
• Each wear indicator TUL consists of a protrusion of rubber 18, called second threshold projection, arranged transversely to the bottom of the groove 16 in which it is located and extending radially from the bottom of this groove 16.
• the second threshold SL is reached after the first threshold SS.
• the threshold SL is more advanced than the threshold SS.
• the threshold SL is reached when the wear of the tire is greater than the wear for which the threshold SS is reached. In this case, the height h s is greater than the height h L.
• the threshold SS corresponds to wear beyond which the tire has performance that can be degraded on a wet coating.
• the threshold SL corresponds to a wear beyond which the tire no longer complies with the legal requirements.
• each projection 17 of first threshold is circumferentially separated from each projection 18 of second threshold SL. In other words, the projections 18 and 17 do not touch each other.
• the height of the projections 17, 18 is smaller than the depth of the grooves 16 so that each witness TUS, TUL includes a space above projections 17, 18, that is to say at the top of the projections 17, 18. Thus, even when the tread is in contact with a flat and smooth ground, the ground does not come into contact with the projections 17, 18.
• the projections 17, 18 are arranged so that, regardless of the radial wear of the tire 10, two circumferentially successive projections 17, 18 of the same groove 16 and the groove 16 define an open space to the air during their passage in the area of contact of the tire 10 with the ground.
• the pairs of projections 17, 18 concerned comprise two projections 17, two projections 18 or a projection 18 and a projection 17.
• the distance separating two projections 17,18 circumferentially successive in the same groove 16 is greater than a predetermined distance, here the length of the contact area, so that, even beyond one of the threshold SS and / or SL, the projections 17, 18 and the groove 16 form a space that remains open to air during their passage in the area of contact of the tire 10 with the ground.
• Figure 2A There is shown in Figure 2A a developed diagram of the tread of the tire of Figure 1.
• the tire 10 comprises sets of projections 17, 18 respectively of first and second threshold SS, SL arranged at the bottom of different grooves 16.
• each set of first threshold projections SS comprises two projections 17 and each SL second projection assembly includes two projections 18.
• Each projection 17, 18 of each assembly is substantially axially aligned with each other projection 17, 18 of the assembly.
• the projections 17 of the first threshold SS are equi-distributed circumferentially on the tire 10, as well as the projections 18 of the second threshold SL. Thus, beyond each threshold SS, SL, during the rotation of the tire, the projections 17, 18 enter at a constant time interval in contact with the ground when the tire rolls at a substantially constant speed.
• the projections 17 and 18 are equally distributed circumferentially on the tire 10. Thus, beyond the threshold SL, during the rotation of the tire, the projections 17 and 18 enter a constant time interval in contact with the ground when the tire rolls at a substantially constant speed.
• the tire 10 comprises 12 projections 17, 18 and 6 projections 17.
• two circumferentially successive projections 18 are arranged at the bottom of different grooves 16 and offset axially with respect to one another so that the projections 18 of second threshold SL are not circumferentially equi-distributed.
• the wear of the tread 12 of the tire 10 shown in FIG. 3 is 6 mm, that is to say greater than the threshold SS, in other words greater than the distance separating, when the tire 10 is nine, the top of the projections 17 of the surface of the tread 12. In view of the wear greater than SS, the top of the projections 17 is at the same level as the surface of the tread 12.
• the wear of the tire is below the threshold SL, that is to say lower than the distance separating, when the tire 10 is new, the top of the projections 18 of the surface of the tread 12.
• the top of the projections 18 is at a lower level than that of the tread at this stage of wear.
• each projection 17 has a height less than the height h s .
• the height is less than 2.2 mm and is 2 mm for a wear of 6 mm. This height is equal to the difference between the depth of each groove 16 and the wear of the tire 10.
• each projection 17 of the first threshold SS is arranged to come into contact with the ground during its passage through the contact area of the tire 10 with the ground. She then emits a sound. Between the thresholds SS and SL, each projection 18 of second threshold SL is not in contact with the ground because of the space between the top of each projection 18 and the ground.
• FIG. 4 There is shown in Figure 4 the tire 10 of Figures 1 and 2 worn beyond the threshold SL.
• the wear of the tread 12 of the tire 10 shown in FIG. 4 is 7 mm, that is to say greater than the threshold SL, but also at the threshold SS, ie greater than the distance separating when the tire 10 is new, the top of the projections 18 of the surface of the tread 12. Taking into account the wear greater than the second threshold SL, the top of the projections 18, but also that of the projections 17, is at same level as the surface of the tread 12.
• each projection 17 and 18 has a height less than the height h L.
• the height is less than 1, 6 mm and is 1 mm for a wear of 7 mm. This height is equal to the difference between the depth of each groove 16 and the wear of the tire 10.
• each projection 18 of second threshold SL is arranged to come into contact with the ground during its passage through the contact area of the tire 10 with the ground.
• each projection 17 of the first threshold SS is arranged to come into contact with the ground during its passage through the contact area of the tire 10 with the ground.
• Figure 5A a developed diagram of the tread 12 of a tire according to a second embodiment of the invention. Elements similar to those shown in the preceding figures are designated by identical references.
• first circumferentially successive threshold SS are arranged at the bottom of the same groove 16. All the projections 17 of the first threshold SS are arranged at the bottom of the same groove 16.
• the tire comprises at most 4, and preferably at most 3 projections 17 of first threshold SS.
• two circumferentially successive projections 18 are arranged at the bottom of different grooves 16 and offset axially with respect to each other so that the projections 18 of second threshold SL are not circumferentially equi-distributed.
• FIG. 6 shows a developed diagram of the bearing 12 of a tire according to a third embodiment of the invention. Elements similar to those shown in the preceding figures are designated by identical references.
• the tire 10 has 4 projections 17 of the first threshold SS and 8 projections 18 of the second threshold SL.
• Two protuberances 17 of first circumferentially successive SS threshold are arranged at the bottom of different grooves 16.
• Two protrusions 18 of second threshold circumferentially successive and circumferentially located between two projections 17 of first threshold are arranged at the bottom of two different grooves 16.
• Two protrusions 18 of second threshold circumferentially circumferentially and circumferentially located on either side of the same projection 17 of the first threshold are arranged at the bottom of the same groove 16.
• Each groove 16 is delimited by an axial wall 24 forming the bottom of the groove 16 and two radial walls 25 forming the sides of the groove 16.
• the projections 18 of the tire according to the fourth embodiment extend only partially. between the two radial walls 25 so that the tire 10 comprises at least one channel 26 for fluid passage between each projection 18 and one of the walls 25 delimiting each groove 16.
• the channel 26 allows the flow of air or water water flowing through the furrows 16.
• each projection 17 of each TUS control is contiguous to a projection 18 of a control TUL.
• FIG. 10 which shows the tire according to the sixth embodiment with a wear corresponding to the threshold SS
• the two witnesses TUS and TUL thus form a single TUS-TUL wear indicator consisting of a projection 28 arranged at the bottom of the groove 16.
• the projection 28 has a general staircase shape and comprises first and second parts of rubber 30, 32 forming respectively the projections 17, 18.
• Each first and second portion 30, 32 respectively has a radially outer surface 34, 36 intended to come into contact with the ground during the passage of the projection 28 in the contact area of the tire 10 with floor.
• the radial dimension of the surface 34 is greater than the radial dimension of the surface 36.
• the height h s of the first part 30 is greater than the height h L of the second part 32.
• each projection 17 comprises a small sound cavity 38 formed in the projection 17.
• the cavity 38 is formed in the second portion 32 of the wear indicator. TUS-TUL.
• the sound cavity 38 is shaped so as to open radially outwardly of the tire 10 and so as to be closed by the ground so as to substantially sealed during its passage in the area of contact of the tire 10 with the ground.
• any distribution of the projections of each threshold may be considered as long as the projections are equi-distributed circumferentially around the tire.
• a cavity may also be provided in the first threshold projections when these are circumferentially separated from the second threshold projections.
• the tread may include more than two grooves.
• the projections may be of variable or constant contact section. [098] The projections may extend partially to the bottom of the furrow (s) and delimit a fluidic passage channel without the protrusions of the legal wear indicators does not extend partially to the bottom of the furrow (s) and delimits a fluidic passage , and vice versa.
• the tire may comprise more than two wear thresholds.
• the tire may include several thresholds less advanced than the legal wear threshold.
• the projection or projections are equi-distributed circumferentially on the tire.

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

Applications Claiming Priority (2)

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ID=46579155

Family Applications (1)

Country Status (7)

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Citations (1)

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• 2011
  • 2011-06-15 FR FR1155235A patent/FR2976520B1/fr not_active Expired - Fee Related
• 2012
  • 2012-06-15 US US14/126,157 patent/US20140174613A1/en not_active Abandoned
  • 2012-06-15 EP EP12738494.9A patent/EP2720886A1/de not_active Withdrawn
  • 2012-06-15 WO PCT/FR2012/051341 patent/WO2012172261A1/fr active Application Filing
  • 2012-06-15 BR BR112013030731A patent/BR112013030731A2/pt not_active IP Right Cessation
  • 2012-06-15 CN CN201280029163.1A patent/CN103608193A/zh active Pending
  • 2012-06-15 JP JP2014515265A patent/JP2014516868A/ja active Pending

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