# US 11,305,584 B2 · Tire crown for a heavy duty civil engineering vehicle > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 11,305,584 B2 - Document ID: US11305584B2 - Status: Granted - Kind: B2 - Application number: 16/462,857 - Filed: 2017-11-17 - Published: 2020-03-12 - Granted: 2022-04-19 - Earliest claimed: 2016-11-21 - Assignees: Compagnie Generale Des Etablissments Michelin - Applicants: Compagnie Generale Des Etablissements Michelin - Inventors: Alain Domingo; Olivier Spinnler - Web page: https://patentgrep.com/patent/US11305584B2 ## CPC - B60C 9/2006: {consisting of steel cord plies only} - B60C 11/042: {further characterised by the groove cross-section} - B60C 11/1259: {Depth of the sipe} - B60C 11/1272: {Width of the sipe} - B60C 2009/2016: {comprising cords at an angle of 10 to 30 degrees to the circumferential direction} - B60C 2009/2019: {comprising cords at an angle of 30 to 60 degrees to the circumferential direction} - B60C 2009/2074: {Physical properties or dimension of the belt cord} - B60C 2011/0353: {characterised by width} - B60C 2011/0355: {characterised by depth} - B60C 2011/129: {Sipe density, i.e. the distance between the sipes within the pattern} - B60C 2200/065: for construction vehicles - B60C: VEHICLE TYRES; TYRE INFLATION; TYRE CHANGING; CONNECTING VALVES TO INFLATABLE ELASTIC BODIES IN GENERAL; DEVICES OR ARRANGEMENTS RELATED TO TYRES ## Abstract Crown of a tire for a heavy vehicle that is desensitized to attacks. The tire (1) comprises tread (2) having a median degree of surface siping TLC, expressed in m/m2, equal to the ratio between the cumulative length LDC of the cuts (21), present in a median portion of tread of axial width WC, and the median area AC of the radially outer surface (23) of the tread (2), and protective reinforcement (4) comprising at least two protective layers (41, 42) that are formed of elastic metallic reinforcers and have a maximum breaking strength Rmax, expressed in daN/m, such that the median degree of surface siping TLC of tread (2) is at least equal to 5 m/m2 and a coupling ratio CC, equal to the ratio between the maximum breaking strength Rmax and the median degree of surface siping TLC, is at least equal to 18 000 daN. ## Claims ### Claim 1 A tire for a heavy vehicle of construction plant type, comprising: a tread; and the tread, having a radial thickness HT at least equal to 60 mm, comprising: cuts having a radial depth HD and a width WD, and elements in relief separated by the cuts; at least some of the cuts, referred to as effective cuts, having a radial depth HD at least equal to 50% of the radial thickness HT and a width WD at most equal to 20% of the radial depth a crown reinforcement radially on the inside of the tread, the crown reinforcement comprising: a protective reinforcement: a working reinforcement; and a hoop reinforcement; the protective reinforcement, which is radially outermost, comprising: two protective layers, in contact with one another over a median axial width WC, wherein a radial spacing between the two protective layers, measured at a same axial position of each of two protective layers, is constant over the median axial width WC and increases beyond the median axial width WC, comprising elastic metallic reinforcers, that form an angle of between 15° and 45° with a circumferential direction, each said protective layer having a breaking strength R per unit of layer width, expressed in daN/m, Rmax being the maximum value of the breaking strengths R of the protective layers; the working reinforcement comprising at least two working layers, comprising inextensible metallic reinforcers that are crossed from one working layer to the next and form an angle of between 15° and 45° with the circumferential direction of the tire; and the hoop reinforcement comprising at least one hooping layer, comprising metallic reinforcers that form an angle at most equal to 15° with the circumferential direction, wherein the median degree of surface siping TLC of the tread, defined as the ratio between the cumulative length LDC of the effective cuts, present on a median portion of the tread having an axial width equal to WC, and a median area AC of the radially outer surface of the tread equal to 2ΠRE*WC, where RE is the external radius of the tire, is at least equal to 5 m/m2 and wherein the coupling ratio CC, defined as the ratio between the maximum value Rmax of the breaking strengths R of the protective layers and the median degree of surface siping TLC of the tread, is at least equal to 18 000 daN. ### Claim 2 (depends on 1) The tire for a heavy vehicle of construction plant type according to claim 1, wherein the coupling ratio CC is at least equal to 24 000 daN. ### Claim 3 (depends on 1) The tire for a heavy vehicle of construction plant type according to claim 1, wherein the coupling ratio CC is at most equal to 72 000 daN. ### Claim 4 (depends on 1) The tire for a heavy vehicle of construction plant type according to claim 1, wherein the median degree of surface siping TLC is at least equal to 5.8 m/m2. ### Claim 5 (depends on 1) The tire for a heavy vehicle of construction plant type according to claim 1, wherein the median degree of surface siping TLC is at most equal to 15 m/m2. ### Claim 6 (depends on 1) The tire for a heavy vehicle of construction plant type according to claim 1, wherein the circumferential median degree of surface siping TLCX of the tread, defined as the ratio between the sum of the projections, in the circumferential direction, of the lengths of the effective cuts, present on a median portion of tread having an axial width equal to WC, and a median area AC of the radially outer surface of the tread equal to 2ΠRE*WC, where RE is the external radius of the tire, is at least equal to 2.5 m/m2. ### Claim 7 (depends on 1) The tire for a heavy vehicle of construction plant type according to claim 1, the tire having an axial direction parallel to its axis of rotation, wherein the axial median degree of surface siping TLCY of the tread, defined as the ratio between the sum of the projections, in the axial direction, of the lengths of the effective cuts, present on a median portion of tread having an axial width equal to WC, and a median area AC of the radially outer surface of the tread equal to 2ΠRE*WC, where RE is the external radius of the tire, is at least equal to 3.5 m/m2. ### Claim 8 (depends on 1) The tire for a heavy vehicle of construction plant type according to claim 1, wherein the maximum value Rmax of the breaking strengths R of the protective layers is at least equal to 150 000 daN/m. ### Claim 9 (depends on 1) The tire for a heavy vehicle of construction plant type according to claim 1, wherein the breaking strength R of the radially outermost protective layer is equal to the maximum value Rmax of the breaking strengths R of the protective layers. ### Claim 10 (depends on 1) The tire for a heavy vehicle of construction plant type according to claim 1, wherein the breaking strength R of each protective layer is equal to the maximum value Rmax of the breaking strengths R of the protective layers. ### Claim 11 (depends on 1) The tire for a heavy vehicle of construction plant type according to claim 1, wherein the minimum value Rmin of the breaking strengths R of the protective layers is such that the ratio Rmin/TLC is at least equal to 18 000 daN. ### Claim 12 (depends on 1) The tire for a heavy vehicle of construction plant type according to claim 1, wherein the elastic metallic reinforcers of the protective layers are multistrand ropes, made up of a single layer of K strands, K being between 3 and 5, each strand being made up of metal threads. ### Claim 13 (depends on 1) The tire for a heavy vehicle of construction plant type according to claim 1, wherein the working reinforcement extends beyond the median axial width WC. ### Claim 14 (depends on 1) The tire for a heavy vehicle of construction plant type according to claim 1, wherein the hoop reinforcement extends less than the median axial width WC. ### Claim 15 (depends on 1) The tire for a heavy vehicle of construction plant type according to claim 1, wherein an overall volumetric void ratio is a ratio between a total volume of the cuts in the median portion and a sum of the total volume of the cuts in the median portion and a total volume of the elements in relief of the median portion. ### Claim 16 (depends on 15) The tire for a heavy vehicle of construction plant type according to claim 15, wherein an overall volumetric void ratio is at least equal to 12%. ### Claim 17 (depends on 1) The tire for a heavy vehicle of construction plant type according to claim 1, wherein an axial end of the median axial width WC is beyond a respective axially outermost cut. ### Claim 18 (depends on 1) The tire for a heavy vehicle of construction plant type according to claim 1, wherein at least one of the two protective layers has a convex shape beyond the median axial width WC so that the two protective layers radially diverge from one another beyond the median axial width WC, measured at a same axial position of each of two protective layers. ### Claim 19 (depends on 1) The tire for a heavy vehicle of construction plant type according to claim 1, wherein at least one of the two protective layers has a convex shape beyond the median axial width WC so that the two protective layers radially converge after a maximum radial spacing, measured at a same axial position of each of two protective layers.