Tire maintenance method

Abstract

Method for measuring a tire comprising a substantially continuous shoulder block and at least two substantially circumferential grooves, a database associating tires and geometric data, including the identification of two points located directly within the grooves to determine a third point from which a distance measurement to the tread surface is taken, this distance being compared to a threshold to initiate a maintenance operation. Figure for the abstract: Fig 1

Description

Title of the invention: Method for maintaining a tire Scope of the invention

[0001] The invention relates to a method for measuring tire wear, and more specifically, this method for measuring the wear of a continuous shoulder block of a tire, the purpose of which is to plan a maintenance operation for said tire. This measurement can be applied to certain truck tires, certain sport-touring tires with continuous shoulder blocks, but it primarily concerns aircraft tires. Technological background

[0002] The tire has a substantially toroidal shape around an axis of revolution coinciding with the axis of rotation of the tire. This axis of revolution defines three directions classically used by those skilled in the art: an axial direction, a circumferential direction and a radial direction.

[0003] By axial direction, we mean the direction parallel to the axis of revolution of the tire, that is to say the axis of rotation of the tire.

[0004] By circumferential direction, we mean the direction which is perpendicular to both the axial direction and to a radius of the tire.

[0005] By radial direction, we mean the direction along a radius of the tire, that is to say any direction intersecting the axis of rotation of the tire and perpendicular to this axis.

[0006] By meridian plane, we mean a plane containing the axis of rotation of the tire.

[0007] By radially inside, and radially outside respectively, we mean closer to the axis of rotation of the tire, and further from the axis of rotation of the tire respectively. By axially inside, and axially outside respectively, we mean closer to the median plane of the tire, and further from the median plane of the tire respectively.

[0008] By median plane of the tire, we mean the plane perpendicular to the axis of rotation of the tire and which passes through the axial middle of the tread.

[0009] Typically, the tire is provided with a carcass reinforcement comprising at least one layer of carcass, textile or metallic, coated with a polymer. The carcass reinforcement is radially surmounted by a crown reinforcement comprising one or more crown layers, this crown reinforcement being itself surmounted by a tread.

[0010] A tire is provided with a tread having a rolling surface intended to be in contact with the road. By "rolling surface" of the The tread is defined as the surface encompassing all the points of the tire that will come into contact with the ground under normal driving conditions. The tread also includes a wear layer of rubber extending from the tread surface to the outermost radial point of the wear indicators. This tread includes grooves in substantially axial, circumferential, or oblique directions. A substantially circumferential groove extending around the entire perimeter of the tire and with a width of at least 5 mm is a circumferential groove. The shoulder block is the portion of the tire delimited by the axial end of the tread and the outermost axial groove.

[0011] In use, the tread wears down through a sliding motion with the ground. The tread depth when new decreases to a threshold determined by a standard or the manufacturer, which defines when the tire must be changed. In the specific case of aircraft tires, patent application FR3060821-A1 mentions that the tire's shoulder block wears particularly during the aircraft's taxiing phases. Taxiing phases correspond to the use preceding takeoff or following landing. Shoulder block wear becomes the predominant wear mechanism during this phase and therefore necessitates the implementation of a maintenance measure.

[0012] It is essential for transport professionals to manage wear-related maintenance as efficiently as possible. This maintenance operation consists, at a minimum, of removing and replacing the tire to keep the vehicle in compliance with technical and safety requirements. For example, premature tire removal will negatively impact an operator's profitability, while delayed removal can lead to regulatory or even safety non-compliance, immobilizing the vehicle.

[0013] The tread rests on a crown reinforcement comprising a superposition of crown layers extending circumferentially and radially outside a tire carcass reinforcement. Each crown layer consists of parallel metallic or textile reinforcements coated with a polymeric material such as an elastomer or coating compound. In the specific case of excessive wear, the appearance of a crown layer in the shoulder area will necessitate immediate removal, which is not included in the maintenance plan. This will result in additional costs due to vehicle downtime; therefore, it is essential to prevent this situation by implementing a predictive maintenance plan by the professional.

[0014] Several methods exist to allow for wear diagnosis. There are wear indicators which are visible references located in the bottom of a groove. These wear indicators require visual inspection by the user or the person responsible for maintenance. Each wear indicator provides a localized check in the immediate vicinity of the indicator itself. "In the immediate vicinity" is defined as a circle with a radius of approximately 5 mm around the indicator. Tools also exist for measuring the remaining tread depth, such as a tread depth gauge. The tread depth gauge measures the height of the tread between the bottom of the groove and at least one contact point on the rolling surface around the groove.

[0015] When new, the tread depth of the tire is at its maximum. A wear ratio can therefore be defined as the ratio between the measured tread depth and the tread depth when new. This same ratio is then used to define a wear rate, such that the wear rate is equal to the wear ratio subtracted from 1. This wear rate determines the amount of remaining tread to be worn.

[0016] The shoulder block of the tire, and in particular the shoulder block of an aircraft tire, is substantially continuous around the tire's circumference. "Substantially continuous" means that a tread depth gauge cannot be used, no visual wear indicators are present, and no incisions wider than 2 mm are present. Such incisions would allow for the placement of wear indicators. The tire and its crown reinforcement will deform plastically according to usage. This is particularly true for tires made of textile plies, such as aircraft tires, and especially true when the reinforcement is subjected to high thermal stresses, loads, speeds, and pressures, as is the case with aircraft tires. It should be noted that aircraft tires can be inflated to 15 bar, reach speeds exceeding 300 km / h, and experience local temperatures exceeding 120°C.This plastic deformation, combined with the fact that no reference groove is accessible at the shoulder, prevents a reliable measurement of wear on the continuous shoulder block based on the relative radii of the bearing surface at the shoulder. Under these conditions, it is not possible to differentiate the proportion of wear and plastic deformation in the variation of the shoulder block profile. This problem does not exist for the other blocks on the surface; wear indicators, linked to a reference groove and located near the area to be monitored, undergo the same plastic deformation of the top reinforcement as the adjacent blocks. A reference groove is defined as an area that can accommodate a wear indicator or a depth gauge that does not come into contact with the ground and therefore does not wear.

[0017] The present invention aims to provide a method for measuring the wear of a tire at the level of a substantially continuous shoulder block by taking into account the plastic deformation of the tire with use. Description of the invention

[0018] This objective was achieved by implementing a method for measuring the shoulder wear of a tire:

[0019] The tire comprising a tread including a tread surface intended to come into contact with the ground,

[0020] The tread comprising at least one substantially continuous shoulder block and at least two substantially circumferential grooves,

[0021] The method using a database associating tire types and geometric data of these tires, at least one measuring tool, and comprising the following steps: • Identification, using a measuring tool, of a first point A located in the groove directly adjacent to the shoulder block, substantially continuous, said first point being the most radially inner point of said groove, • Identification with a measuring tool of a second point B located in the groove directly adjacent to the groove directly adjacent to the shoulder block, substantially continuous, said second point being the most radially internal point of said groove and positioned in the same meridian plane as the first point A, • The type of tire is identified, • The database associates with the tire type a distance allowing the positioning of a third point RI on the line (A, B) joining the first two points, RI being axially external to the first point A, • A measuring tool allows the identification on the tire of a fourth point II positioned in the same meridian plane as the first point A, said point being a projection of the third point RI onto the tread surface of the tire, • Determination of the distance Dl, known as the first threshold distance, between the third point RI and the fourth point IL

[0022] The elastomer thickness between the groove bottom and the outermost radially exposed crown layer is not deformed by operating stresses and does not wear, as it does not come into contact with the ground. This reference thickness remains stable throughout the tire's service life, particularly for aircraft tires. Furthermore, this thickness undergoes the plastic deformations of the crown reinforcement like the rest of the tread; the groove bottom is therefore a reliable and accessible reference point for measuring tire wear. Used as a reference, groove bottoms prevent interference from the plastic deformation of the crown structure. Thus, using a straight line passing through the bottom of at least two grooves provides a reliable reference for the wear measurement and simultaneously allows the measurement point to be shifted to an inaccessible area. like a virtually continuous shoulder block. The method therefore consists of referring to the line passing through the groove bottoms of the grooves closest to the shoulder block, and positioning point RI according to the tire type, preferably at the end of the crown reinforcement to account for the plastic deformation of the reinforcement. This positioning is virtual, as point RI is inside the tread; however, it is possible, from a tread profile including the grooves, to plot A, B, and RI on a sheet of paper if necessary. The position of point RI therefore depends on the tire's design and thus on its type, brand, and size. This distance is preferably defined by the manufacturer.If this distance is not defined by the manufacturer, point RI will be positioned on the line (A,B), axially outside point A, and preferably at the end of the outermost radially outermost crown layer of the crown reinforcement, based on measurements taken on a meridian cross-section. The database contains, depending on the tire type, an associated distance that allows the positioning of point RI independently of the crown reinforcement architecture. The tire type is defined as data that characterizes the product, such as the brand, size, commercial name, or product code. The product code comes from a tire manufacturer's reference database or a customer's database. The method then consists of defining point II as a projection of RI onto the tread surface, in the same meridian plane as point A. The projection is oriented axially outward and radially outward from point A.The projection preferably makes an angle of less than 30° with the radial direction, and more preferably, the projection is made along a substantially radial direction. Orienting the projection at an angle of less than 30° allows the wear control to be located in a region particularly sensitive to wear of the shoulder block. By substantially radial, we mean a direction inclined at a maximum of 5° with respect to the axis of the radial projection of point RL.

[0023] The first threshold distance Dl, is the remaining height of elastomer at the level of the continuous shoulder block, and preferably located at the end of the most radially outermost top layer of the top reinforcement.

[0024] In a particular embodiment, a mechanical measuring tool that does not require a profile survey is used. The mechanical tool is supported in the two groove bottoms adjacent to the substantially continuous shoulder block. Subsequently, a probe is extended in the outward axial direction, starting from the first support point located in the groove directly adjacent to the shoulder block, by a distance dependent on the type of tire. The probe, attached to a depth gauge, is supported on the tread surface at the level of the substantially continuous shoulder block and allows for a direct measurement, by the probe, of the sculpture height corresponding to the distance between RI and II, called first threshold distance Dl.

[0025] In a particular embodiment of said measurement method, there are at least two points, the innermost radial points in at least one of the grooves. Under these conditions, information from the database associates a rule with the tire type, allowing the point to be selected. If no database is available, the point located closest to the center of the groove is chosen.

[0026] In a particular embodiment of said measurement method, point RI is located outside the tread profile. Outside means that point RI is outside the tire components. In this case, the tread depth Dl is negative. If point RI is located substantially on the tread profile, then the measurement is equal to zero.

[0027] In an advantageous and optional implementation, the method is supplemented by the steps comprising: • The database associates with the tire type a second distance and an angle DA allowing the positioning of a fifth point R2 on the line, called the second line, passing through the third point RI and making an angle equal to DA with the line (A, B), R2 is positioned in the same meridian plane as point A, axially external and radially internal to RI, • A maintenance tool allows the identification on the tire of a distance, in the meridian plane including the first point A, said distance D2 is the distance from the fifth point R2 to the tread surface (3).

[0028] The wear profile of the shoulder block becomes particularly irregular under certain usage conditions. Such wear profiles can appear, in particular, if the tire is not used under typical conditions, such as inflation below or above the recommended pressure, or excessive braking. Under these specific usage conditions, the mass of elastomer radially located on the inner edge (A,B) of the substantially continuous shoulder block wears at least as quickly as the mass of elastomer located radially on the outer edge (A,B) of the same substantially continuous shoulder block. It is advantageous to supplement this method by allowing the quantification of this wear in this particular area of ​​the substantially continuous shoulder block.To achieve this, a second reference line linked to RL must be defined. Advantageously, this second line intersects the line (A,B) at point RI, thus maintaining a reliable reference to the furrow bottoms, which are not disturbed by the plastic deformation of the apex architecture. Preferably, this second line is substantially parallel to the line passing through the axial ends of the apex layers whose axial width is greater than the axial width of the outermost radially exposed apex layer, in order to decouple the deformation. Plastic formation of the wear peak of the tread compound in this area. Point RI and the second line can similarly be determined from the axial ends of the peak layers if this information is not available in the database. In addition to the data necessary for positioning point RI, the database contains an angle for orienting the second line and a second distance for positioning point R2 on this second line. Advantageously, this second point R2, positioned in an area axially outside and radially inside RI, allows exploration of the substantially continuous portion of the shoulder block located radially inside the line (A,B). The method then consists of defining a point 12, as a projection of R2 onto the tread surface, in the same meridian plane as point A.The projection is oriented axially outwards, and preferably at an angle of less than 30° to the direction perpendicular to the second line, and more specifically, substantially perpendicular to the second line. Orienting the projection at an angle of less than 30° improves measurement accuracy, particularly when using a mechanical tool such as a depth gauge probe. For this purpose, a probe has a telescopic axis, which is best oriented roughly in line with the surface to be measured. This eliminates the risk of the axis binding and minimizes the error associated with a rounded contact point. Since the contact point is not exactly the same at different angles of the probe relative to the contact surface, this mechanism introduces a measurement error.By substantially perpendicular, we mean a direction inclined at a maximum of 5° around the axis of the perpendicular projection of point R2. In a final step, we define the distance D2 as a distance representative of the wear corresponding to the remaining height of elastomer at the level of the continuous shoulder block.

[0029] In a particular embodiment, the measuring tool allows for the recording of a profile of the rolling surface in the meridian plane, including the profile of the two grooves directly adjacent to the shoulder block. Advantageously, obtaining such a profile allows, with the use of data contained in the database, a geometric calculation of points A, B, RI, and II, and even R2 and 12. This calculation can be performed by an algorithm implemented in a maintenance management application used by the maintenance professional. This type of recording is described, for example, in document EP3028262.

[0030] In an advantageous embodiment, the method uses a calculator and comprises the following steps: • The database associates with the tire type a first reference distance Ref1 or respectively a second reference distance Ref2 of the new tire profile (8), relating to the third point RI or respectively relating to the fifth point R2, • We calculate the first wear rate Txl or respectively a second wear rate Tx2 from the wear ratio, calculated from DI and Refl, or respectively D2 and Ref2. "or" here is inclusive and should be understood as including either possibility, or both possibilities.

[0031] In a particular embodiment, it is advantageous for the distances DI and D2, which represent a measured elastomer height, to be normalized with respect to an elastomer height available when the tire is new. This makes it easier for tire maintenance professionals to interpret the figures from one tire to another. Two reference elastomer heights for new tires, Refl and Ref2 respectively, are thus defined, corresponding to the measurements of the heights Dl and D2, respectively. In addition to the aforementioned information, the database contains the reference heights for new tires, Refl and Ref2 respectively, which allow for the calculation of a wear rate Txl and Tx2 respectively, defined by Txl = 1 - (D1 / Refl) and Tx2 = 1 - (D1 / Refl), respectively. Advantageously, the calculator enabling this calculation is directly integrated into a computer application dedicated to the tire maintenance professional.The maintenance management application can display wear rates considering values ​​ranging from 0 to 1 or 0% to 100%, depending on the format chosen by the user.

[0032] In a particular embodiment, for a tire having a substantially continuous block at each shoulder, said method is applied to one and then the other shoulder block of said tire.

[0033] Advantageously, the method applied to one shoulder can be applied strictly symmetrically to the other shoulder.

[0034] In a particular embodiment, the second groove, adjacent to the first groove adjacent to the shoulder block, is substantially centered on the median plane of the tire, thus serving as the same point B for one and then the other shoulder block.

[0035] The invention also includes a maintenance method using the measurement method according to the invention, wherein the maintenance method comprises the following steps: • The database associates a maintenance trigger threshold with the tire type, • A dismantling operation is triggered if the distance Dl is less than the maintenance trigger threshold.

[0036] Advantageously, the maintenance method includes, if the measurement method also includes the measurement of distance D2, the following steps: • The database associates a second maintenance trigger threshold with the tire type, • A dismantling operation is triggered if the distance D2 is less than the second maintenance trigger threshold.

[0037] The professional must be able to make a decision based on the measured distances DI and D2 in order to trigger, if necessary, a corrective maintenance action such as changing the tire. Advantageously, the database therefore contains, for each measurement point RI and R2 respectively, a trigger threshold and a second trigger threshold allowing a comparison of distances DI and D2 respectively. If distances DI and D2 respectively are less than the respective thresholds in the database, then a corrective maintenance action such as changing the tire is carried out.

[0038] In a particularly advantageous embodiment, the database contains at least one tire behavior law, and more specifically at least one law corresponding to the shoulder block wear rate. This wear rate allows, by comparison with the initial measurements of DI and D2, the definition of a projected maintenance date. The technician can thus anticipate maintenance operations by planning them. Maintenance operations can be streamlined over time, thereby not only optimizing maintenance costs but also limiting aircraft downtime.

[0039] In an advantageous implementation, the method comprises the following steps: • The tire is individually identified • A maintenance event is stored in a database which associated with the individual identification of the tire, at least one wear rate Txl or Tx2, or at least one of the distances to the surface DI or D2, • After at least two measurement events, a computer proposes a preventive maintenance date or an immediate maintenance operation.

[0040] Individual tire identification allows for the recording and association of several measurement events with a history. In addition to measurements, the history is associated with data from tire information such as: a manufacturing date, a manufacturing plant, and a wear measurement history of an area such as the shoulder block. Preferably, this history is stored in a knowledge base. A knowledge base is understood to be a means of storing a set of histories associated with a set of individual tires. In a particular embodiment, this knowledge base is included within the database. Advantageously, the knowledge base that associates at least Two shoulder block wear measurement events allow for the identification of a trend related to actual tire usage. Advantageously, a predictive maintenance algorithm will leverage this trend to adjust the scheduled maintenance date and improve its accuracy. Thus, the professional, through a maintenance management application that combines a database and a knowledge base, benefits from a more accurate scheduled maintenance date thanks to knowledge of actual tire usage.

[0041] Advantageously, the knowledge base, which includes a set of measurement histories, becomes a source of information for a second algorithm whose purpose is to determine a constitutive law, and particularly a wear rate law, and more specifically a shoulder block wear rate law. The algorithm thus makes it possible to optimize a constitutive law such as the shoulder block wear rate by taking into account the tire type and its actual use. Wear prediction through the updating of these laws becomes more accurate over time.

[0042] Preferably, this method of tire maintenance applies to an aircraft tire but can just as easily be applied to a heavy truck tire. Brief description of the drawings

[0043] Figure 1 schematically represents, without scale, a partial meridional section (5) of a vertex of an aircraft tire, axially truncated by the projection (7) of the median plane. The figure represents a tread (2) of a tire comprising a substantially continuous shoulder block (1) and two circumferential grooves (6). A vertex reinforcement (9), radially internal to the tread (2), comprises a superposition of vertex layers (4) extending in the circumferential direction. Each vertex layer (4) consists of textile or metallic reinforcements coated with an elastomeric compound. A profile of the tread surface (3) after use is shown in solid lines, and a profile of a new tire (8) is shown in dashed lines.The drawing also shows the innermost radial points A and B of the grooves (6) adjacent to the substantially continuous shoulder block (7), the point RI on the line (AB) and preferably directly above the end of the outermost radially facing crown layer (4), allowing the measurement of the distance DI, here the radial distance from RI on the contact patch (7) of the worn tire. Similarly, a second line is shown allowing the positioning of R2, this line being preferably parallel to the ends of the crown layers whose axial width is greater than the axial width of the outermost radially facing crown layer, the distance RI to R2 being defined either by the manufacturer or by [the manufacturer]. the analysis of product wear and tear as the most wear-prone point.

[0044] Figure 2 schematically represents, without scale, a wear measurement tool comprising a frame (21). This tool has two contact points (23) that come into contact with the groove bottoms of the tread (2) of a tire. One of the contact points (23) is fixed to the frame (21). The distance Dab separating the contact points (23) can be adjusted by a groove slide (26) along the groove slide axis (22). The tool has a depth gauge (25) comprising a telescopic probe (24). The longitudinal axis of the probe (20) defines a substantially linear direction of movement of the telescopic probe (24). The depth gauge (25) is connected to the frame (21) by means of a gauge slide (27) and a secondary slide (30).The secondary slide (30) allows adjustment of the distance Drl between the longitudinal axis of the probe (20) and the support point (23) fixed to the frame (21) along the axis of the gauge slide (29). An angle Ar2 between the axis of the gauge slide (29) and the axis of the groove slide (22) can be adjusted via a pivot joint (28) and a distance Dr2 can be adjusted by the gauge slide (27). Detailed description of implementation methods

[0045] In a first embodiment, the tire maintenance professional uses a tool, as illustrated in [Fig. 2], to perform a wear check on the shoulder blocks of the tires of an A320 aircraft. The aircraft is equipped with Michelin tires, size 46 17 R20, and the information necessary for implementing the method is available in a database. To perform a first measurement, the distance Drl defined in the database is adjusted. Then, the maintenance professional positions the two fulcrum points (23) in the groove bottoms directly adjacent to the shoulder block (1) and records the first remaining height value indicated by the depth gauge (25). To perform a second measurement in a second area of ​​the shoulder block, the distance Dr2 and the angle Ar2 defined in the database are adjusted.Then, the maintenance technician positions the two support points (23) in the grooves directly adjacent to the shoulder block (1) and records the second remaining height value indicated on the depth gauge (25). From these two measurement points, two wear rates, Txl and Tx2, are determined and compared to thresholds accessible via the database. Following these measurements, a history is created, including the tire type (46 17 R20), its individual identifier, and the two wear rates, Txl and Tx2, obtained from the measurements. If one of the thresholds is exceeded, the maintenance technician replaces the tire. This check is repeated at regular intervals, once a month, and each time the history associated with the checked tire is updated. The complete tire history for FA320 constitutes a knowledge base, a source of information. for optimizing the thresholds and wear laws of the database.

[0046] In a second embodiment, the tire maintenance professional uses a portable digital tool to perform a wear check on the shoulder blocks of the tires on an A320 aircraft. The aircraft is equipped with Michelin tires, size 46 17 R20, and the information necessary for implementing the method is available in a mobile application accessing a remote database. The portable digital tool is locally georeferenced and equipped with a three-dimensional infrared image sensor. Local georeferencing refers to the operation of quantifying relative displacements in three spatial directions. In this instance, the professional has chosen the RealSense D415 camera (registered trademark) or the integrated digital camera of a mobile phone, which allows for the combination of local geolocation and three-dimensional image capture. The camera communicates with an application installed on the mobile phone.Once the tire type is entered into the application, the first step of the measurement method involves moving the camera near the tread to capture at least 30 images in different directions when using a mobile phone camera, or a single image when using the RealSense D145 camera (registered trademark). The application extracts a tread profile in the meridian plane of the 46 17 R20 tire from the series of images captured by the digital device, such as a mobile phone with a digital camera. Using the data in the database, the application performs a geometric calculation of points A, B, RI, and II, and possibly R2 and 12. The application then determines the two respective wear rates, Txl and Tx2, and checks if the thresholds in the database have been exceeded.A history log, including the tire type (46 17 R20) and its individual identifier, is supplemented with the two wear rates (Txl and Tx2) obtained from measurements. If either threshold is exceeded, the maintenance professional replaces the tire. This check is repeated monthly and updates the history log each time. Ultimately, the complete tire history for the A320 constitutes a knowledge base, providing information for optimizing the thresholds and wear patterns in the database for all application users.

Claims

Claims

1. Method for measuring shoulder wear of a tire: The tire comprising a tread (2) comprising a tread surface (3) intended to come into contact with the ground, The tread (2) comprising at least one substantially continuous shoulder block (1) and at least two substantially circumferential grooves (6), The method using a database associating tire types and geometric data of these tires, at least one measuring tool and comprising the following steps: - Identification with a measuring tool of a first point A located in the groove (6) directly adjacent to the shoulder block (1), substantially continuous, said first point being the most radially inner point of said groove (6), - Identification with a measuring tool of a second point B located in the groove (6) directly adjacent to the groove (6) directly adjacent to the shoulder block (1), substantially continuous,said second point being the most radially inner point of said groove (6) and positioned in the same meridian plane as the first point A, - The type of tire is identified, - The database associates with the type of tire a distance making it possible to position a third point RI on the line (A, B) joining the first two points, RI being axially outside the first point A, - A measuring tool allows the identification on the tire of a fourth point II positioned in the same meridian plane as the first point A, said point being a projection of the third point RI onto the rolling surface (3) of the tire, - Determination of the distance Dl, called the first threshold distance, between the third point RI and the fourth point IL,

2. Method for measuring the shoulder wear of a tire according to claim 1 in which the fourth point II is the radial projection, in the meridian plane of point 1, of the third point RI on the surface of rolling (3) of the tire.

3. Method for measuring the wear of a tire according to claim 1 to 2 in which: - The database associates with the type of tire a second distance and an angle DA making it possible to position a fifth point R2 on the straight line, called the second straight line, passing through the third point RI and making an angle equal to DA with the straight line (A, B), R2 is positioned in the same meridian plane as the point A, axially outside and radially inside RI, - A maintenance tool allows the identification on the tire of a distance, in the meridian plane comprising the first point A, said distance D2 is the distance from the fifth point R2 to the rolling surface (3).

4. Method for measuring the wear of a tire according to claims 1 to 3 in which the measuring tool makes it possible to record a profile of the rolling surface (3), in the meridian plane, including the profile of the two grooves (6) directly adjacent to the shoulder block (1), substantially continuous.

5. Method for measuring the wear of a tire according to claims 1 to 4, using a calculator in which: - The database associates with the type of tire a first reference distance Refll of the new profile (8) of the tire, relative to the third point RI, - The first wear rate Txl is calculated as being the ratio between the distance DI and the first reference distance Refll which is subtracted from 1.

6. Method for measuring the wear of a tire according to claims 3 to 5 in which: - The database associates with the type of tire a second reference distance RefI2 of the new profile (8) of the tire, relative to the fifth point R2, - A second wear rate Tx2 is calculated as being the ratio between the distance D2 and the second reference distance RefI2 which is subtracted from 1,

7. Method for measuring the wear of a tire having a substantially continuous block at each shoulder according to claims 1 to 5 in which said method is applied to one then the other shoulder block (1).

8. Maintenance method using the measurement method according to claims 1 to 7 in which: - The database associates a maintenance trigger threshold with the tire type, - A disassembly operation is triggered if the distance DI is less than the maintenance trigger threshold.

9. Maintenance method according to claim 8 in which: - The database associates a second maintenance trigger threshold with the tire type, - A dismantling operation is triggered if the distance D2 is less than the second maintenance trigger threshold.

10. Maintenance method according to claim 8 or 9 in which: - The database associates a wear rate with the type of tire, - A predictive maintenance date is proposed, calculated from the wear rate and at least one wear rate Txl or Tx2.

11. Maintenance method according to claim 8 to 10 in which: - The tire is individually identified - A maintenance event is stored in a database which associates with the individual identification of the tire, at least one wear rate Txl or Tx2, or at least one of the distances to the surface DI or D2, - After at least two measurement events, a computer proposes a preventive maintenance date or an immediate maintenance operation.

12. A method of maintaining a tire according to any one of claims 8 to 11 for an aircraft tire.

Images