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
  • B60C15/00—Tyre beads, e.g. ply turn-up or overlap
  • B60C15/0009—Tyre beads, e.g. ply turn-up or overlap features of the carcass terminal portion
  • B60C15/0054—Tyre beads, e.g. ply turn-up or overlap features of the carcass terminal portion with ply turn-up portion parallel and adjacent to carcass main portion
• • 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
  • B60C15/00—Tyre beads, e.g. ply turn-up or overlap
  • B60C15/0009—Tyre beads, e.g. ply turn-up or overlap features of the carcass terminal portion
  • B60C15/0027—Tyre beads, e.g. ply turn-up or overlap features of the carcass terminal portion with low ply turn-up, i.e. folded around the bead core and terminating at the bead core
• • 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
  • B60C15/00—Tyre beads, e.g. ply turn-up or overlap
  • B60C15/06—Flipper strips, fillers, or chafing strips and reinforcing layers for the construction of the bead
• • 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
  • B60C15/00—Tyre beads, e.g. ply turn-up or overlap
  • B60C15/06—Flipper strips, fillers, or chafing strips and reinforcing layers for the construction of the bead
  • B60C15/0603—Flipper strips, fillers, or chafing strips and reinforcing layers for the construction of the bead characterised by features of the bead filler or apex
• • 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
  • B60C3/00—Tyres characterised by the transverse section
  • B60C3/04—Tyres characterised by the transverse section characterised by the relative dimensions of the section, e.g. low profile
• • 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
  • B60C9/00—Reinforcements or ply arrangement of pneumatic tyres
  • B60C9/02—Carcasses
  • B60C2009/0269—Physical properties or dimensions of the carcass coating rubber
  • B60C2009/0276—Modulus; Hardness; Loss modulus or "tangens delta"
• • 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
  • B60C15/00—Tyre beads, e.g. ply turn-up or overlap
  • B60C15/0009—Tyre beads, e.g. ply turn-up or overlap features of the carcass terminal portion
  • B60C2015/009—Height of the carcass terminal portion defined in terms of a numerical value or ratio in proportion to section height
• • 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
  • B60C15/00—Tyre beads, e.g. ply turn-up or overlap
  • B60C15/06—Flipper strips, fillers, or chafing strips and reinforcing layers for the construction of the bead
  • B60C15/0603—Flipper strips, fillers, or chafing strips and reinforcing layers for the construction of the bead characterised by features of the bead filler or apex
  • B60C2015/061—Dimensions of the bead filler in terms of numerical values or ratio in proportion to section height
• • 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
  • B60C15/00—Tyre beads, e.g. ply turn-up or overlap
  • B60C15/06—Flipper strips, fillers, or chafing strips and reinforcing layers for the construction of the bead
  • B60C2015/0614—Flipper strips, fillers, or chafing strips and reinforcing layers for the construction of the bead characterised by features of the chafer or clinch portion, i.e. the part of the bead contacting the rim
• • 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
  • B60C15/00—Tyre beads, e.g. ply turn-up or overlap
  • B60C15/06—Flipper strips, fillers, or chafing strips and reinforcing layers for the construction of the bead
  • B60C2015/0617—Flipper strips, fillers, or chafing strips and reinforcing layers for the construction of the bead comprising a cushion rubber other than the chafer or clinch rubber
  • B60C2015/0621—Flipper strips, fillers, or chafing strips and reinforcing layers for the construction of the bead comprising a cushion rubber other than the chafer or clinch rubber adjacent to the carcass turnup portion
• • 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
  • B60C2200/00—Tyres specially adapted for particular applications
  • B60C2200/06—Tyres specially adapted for particular applications for heavy duty vehicles

Definitions

• the present invention relates to a tire, radial carcass reinforcement and more particularly to a tire intended to equip vehicles carrying heavy loads and rolling at a high speed, such as, for example, trucks, tractors, trailers or road buses.
• the carcass reinforcement is anchored on both sides in the bead zone and is radially surmounted by a crown reinforcement consisting of at least two layers, superimposed and formed of son or parallel cables in each layer and crossed from one layer to the next in making with the circumferential direction angles between 10 ° and 45 °.
• Said working layers, forming the working armature can still be covered with at least one so-called protective layer and formed of advantageously metallic and extensible reinforcing elements, called elastic elements.
• It may also comprise a layer of low extensibility wires or metal cables forming with the circumferential direction an angle of between 45 ° and 90 °, this so-called triangulation ply being radially located between the carcass reinforcement and the first ply of plywood.
• so-called working top formed of parallel wires or cables having angles at most equal to 45 ° in absolute value.
• the triangulation ply forms with at least said working ply a triangulated reinforcement, which presents, under the different stresses it undergoes, few deformations, the triangulation ply having the essential role of taking up the transverse compression forces of which the object all the reinforcing elements in the area of the crown of the tire.
• Cables are said to be inextensible when said cables have under a tensile force equal to 10% of the breaking force a relative elongation at most equal to 0.2%.
• Circumferential reinforcing elements are reinforcing elements which make angles with the circumferential direction in the range + 2.5 °, -2.5 ° around 0 °.
• the circumferential direction of the tire is the direction corresponding to the periphery of the tire and defined by the rolling direction of the tire.
• the transverse or axial direction of the tire is parallel to the axis of rotation of the tire.
• the radial direction is a direction intersecting the axis of rotation of the tire and perpendicular thereto.
• the axis of rotation of the tire is the axis around which it rotates in normal use.
• a radial or meridian plane is a plane which contains the axis of rotation of the tire.
• the circumferential mid-plane, or equatorial plane is a plane perpendicular to the axis of rotation of the tire and which divides the tire into two halves.
• the measurements of force at break (maximum load in N), tensile strength (in MPa), elongation at break (total elongation in%) and of module (in GPa) are made in traction according to the ISO 6892 standard of 1984.
• the modulus measurements are made in tension according to the AFNOR-NFT-46002 standard of September 1988: the secant modulus is measured in second elongation (ie, after an accommodation cycle). nominal (or apparent stress, in MPa) at 10% elongation (normal conditions of temperature and hygrometry according to AFNOR-NFT-40101 of December 1979).
• Such tires still usually comprise at the beads one or more layers of reinforcing elements called stiffeners. These layers are most often consist of reinforcing elements oriented relative to the circumferential direction of an angle less than 45 °, and usually less than 25 °. These reinforcing element layers have the particular function of limiting the longitudinal displacements of the constituent materials of the bead relative to the rim of the wheel to limit premature wear of said bead. They also make it possible to limit the permanent deformation of the bead on the rim hook, due to the dynamic creep phenomenon of the elastomeric materials. This deformation of the bead can prevent tire retreading when it is excessive. They further contribute to the protection of the low areas of the tire against the aggressions suffered during the assembly and disassembly of the tires on the rims.
• layers of reinforcing elements or stiffener further prevent or delay the unwinding of the carcass reinforcement during accidental and excessive heating of the rim.
• Such tire designs are for example described in FR 2779387 or US 2006/0000199.
• a tire intended to be mounted on a hollow rim comprising a radial carcass reinforcement, consisting of a single carcass reinforcement layer formed of reinforcement elements, said tire comprising a crown reinforcement, itself capped radially with a tread, said tread being joined to two beads by means of two sidewalls, the layer of reinforcing elements of the carcass reinforcement being anchored in each of the beads by turning around a bead wire to form a main portion of the carcass reinforcement layer extending from one rod to the other and a reversal of the bead layer; carcass reinforcement in each of the beads and, in a meridian section of said tire, the upturn of the carcass reinforcement layer and the main part of the carcass reinforcement layer being the only layers of reinforcement elements whose elongation at break is less than 6% present in a zone of the sidewall constituting at least 90% of the surface of the sidewall comprised radially between the end of the upturn of the carcass reinforcement layer and
• main part of the carcass reinforcement layer when the tire is mounted and inflated according to the nominal conditions being at a distance of less than 1 mm from a spline P connecting said first and second points F and E,
• said spline P having a single point of inflection M, the radially innermost part of the spline P being concave for an observer outside the tire, the direction of the tangent T PF of said spline P being given by the straight line passing through said first point F and forming with the radial direction an angle (between 0 ° and 10 ° and less than the angle formed by the line [EF ] and the radial direction, the direction of the tangent T PE of said spline P being given by the straight line passing through said second point E and forming with the radial direction an angle ⁇ 3 ⁇ 4 between 0 ° and 5 ° and less than the angle formed by the line [EF] and the radial direction, said spline P and the line [EF] having a single point of intersection N, distinct from the points E and F, said intersection point N being radially internal to the single M inflection point of said spline P,
• t F voltage or scale factor on the tangent, belonging to the interval [0.5, 2]
• t E voltage or scale factor on the tangent, belonging to the interval [1, 2].
• the meridian section of the tire is defined in accordance with the invention such that the barycentres of the rods form an axially oriented straight line, said centroids being distant from each other by a distance equal to the width of the nominal rim. J increased by 20 mm and decreased by twice the distance measured axially between a barycentre of a bead wire and a point of the outer surface of the tire.
• a hollow rim (15 ° drop center) or wedged seat rim is a monobloc rim, as defined in the ETRTO, whose seats intended to receive the beads of the tire have a shape frustoconical, the angle formed with the axial direction being substantially equivalent to 15 °.
• These seats are also extended by rim hooks of reduced height compared to the hooks of flat base rims whose rim seats have substantially cylindrical shapes.
• any point of the profile of the outer surface S of the tire between said first and second point F and E is at a distance of less than 0.7 mm from the spline P connecting said first and second points F and E.
• the inventors have thus been able to demonstrate that the tires made according to the invention and which have a relatively thin bead zone associated in particular with the absence of layers of complementary reinforcing elements such as stiffeners, allow to lighten the tire and against all expectations to maintain properties in terms of satisfactory endurance, or even to improve.
• the aforementioned contact area is indeed reduced compared to more usual designs, which limits the wear on the carriage and the wear due to the phenomena of de-axialization during rolling.
• this lightening of the bead area of the tire improves the hysteretic losses of the tire and therefore its performance in terms of rolling resistance.
• This effect is even more pronounced that the profile of the outer surface of the tire leads to a decrease in curvature variations in comparison with more usual designs as explained above.
• the inventors have thus considered that the tire thus defined is particularly suitable for particular architectures of the lower zone of the bead can further improve performance in terms of endurance.
• the carcass reinforcement layer being formed of reinforcement elements inserted between two polymer mixture calendering layers, said reversal of the carcass reinforcement layer being separated from the main portion of the carcass reinforcement layer by a first polymeric compound layer extending radially from the bead wire to at least the end of the carcass reinforcement layer overturning and said layer overturning carcass reinforcement being axially outwardly in contact with a second layer of polymeric mixture, itself at least in contact with a third layer of polymeric mixture forming the outer surface of the tire in the region of the bead, said third layer of polymeric mixture being intended in particular to come into contact with the rim, said third layer of polymeric mixture being r outwardly in contact with a fourth layer of polymeric mixture forming the outer surface of a sidewall, and according to the invention, in a meridian section of said tire, ⁇ radially outer end of the first layer of polymeric mixture is radially external to the end of the upturn of the carcass reinforcement layer
• the end of the upturn of the carcass reinforcement layer is radially external to the radially outer end of the second layer of polymeric mixture
• the radially outer end of the second layer of polymeric mixture is radially external to the radially outer end of the third layer of polymeric mixture
• the distance between the end of the upturn of the carcass reinforcement layer and the radially innermost point of the circle circumscribed by the bead wire is between 45 and 90% of the distance between the axially outermost point Z of the main part of the carcass reinforcement layer and the radially innermost point of the circle circumscribing the bead wire
• the tensile modulus of elasticity at 10% elongation of the second polymeric mixture layer is greater than or equal to the tensile modulus of elasticity at 10% of the calender elongation of the carcass reinforcement layer and is strictly inferior at 25 MPa.
• the position of the axially outermost point Z of the main part of the carcass reinforcement is determined on a tire mounted and inflated according to the nominal conditions. This determination can be carried out for example according to a tomography technique.
• the positions of the radially innermost and radially outermost points of the circle circumscribing the bead wire may also be determined according to a tomography technique or are determined on a section of a tire, the spacing of the beads is the same as when the tire is mounted on the mounting rim recommended by the ETRTO, it is neither mounted nor inflated .
• the distance between the axially outermost point Z of the main portion of the carcass reinforcement layer and the radially innermost point of the circle circumscribing the rod is measured on a tire mounted and inflated according to the nominal conditions. .
• This measurement can be performed for example according to a tomography technique.
• the other distances may also be measured according to a tomography technique or are measured on a section of a tire, the spacing of the beads. is the same as when the tire is mounted on the mounting rim recommended by the ETRTO, which is neither mounted nor inflated.
• the main part of the carcass reinforcement layer and the overturning of the carcass reinforcement layer are said to be coupled if the respective reinforcing elements of the main part of the layer of carcass reinforcement and the overturning of the carcass reinforcement layer are separated by a substantially constant thickness of rubber mix and at most 5 mm over a length greater than 15% of the distance between the end of the diaper inversion carcass reinforcement and the radially innermost point of the circle circumscribing the rod.
• the thickness of the rubber mixture separating the respective reinforcing elements of the main portion of the carcass reinforcement layer and the overturning of the carcass reinforcement layer is measured in the normal direction to the reinforcing elements of the main part of the carcass reinforcement layer. the carcass reinforcement layer.
• the respective reinforcing elements of the main part of the carcass reinforcement layer and the overturning of the carcass reinforcement layer are separated by a substantially constant thickness of rubber compound of at most 3.5 mm. and preferably they are separated by a substantially constant rubber compound thickness of at least 0.8 mm and more preferably by a substantially constant rubber compound thickness of at least 2.5 mm.
• a substantially constant thickness of rubber compound separating the respective reinforcing elements of the main part of the carcass reinforcement layer and the overturning of the carcass reinforcement layer is a thickness which does not vary more than 0.5 mm. The variations in thickness are then due to creep phenomena during the manufacture and baking of the tire.
• the crown reinforcement comprising at least one layer of reinforcement elements, the ratio of the radial distance between the axially most outside the main part of the carcass reinforcement layer and the radially outermost point of the nominal rim, ie the radially outermost point of the rim hook, over the radial distance between the axially outer end of the reinforcing element layer of the axially widest vertex armature and the radially outermost point of the nominal rim is less than or equal to 55%.
• the radial distance between the axially outermost point of the main portion of the carcass reinforcement layer and the radially outermost point of the nominal rim is measured on a tire mounted and inflated according to the nominal conditions. This measurement can be performed for example according to a tomography technique.
• the radial distance between the axially outer end of the reinforcing element layer of the axially widest vertex reinforcement and the radially outermost point of the nominal rim can also be measured according to a tomography technique, the tire being mounted and inflated according to the nominal conditions.
• the radial distance between the axially outer end of the reinforcing element layer of the axially widest vertex armature and the radially outermost point of the nominal rim is less than 53%.
• the more usual designs of this type of tire include a reversal of the carcass reinforcement layer such as the distance between the end of the upturn of the carcass reinforcement layer. and the radially innermost point of the circle circumscribing the rod is less than 45% of the distance between the axially outermost point Z of the main portion of the carcass reinforcement layer and the radially innermost point of the circle. circumscribed to the bead wire in particular to improve the performance of the tire in terms of endurance. Indeed, it is customary to design tires with a reversal of the carcass reinforcement layer of reduced length to increase the distance between the overturning of the carcass reinforcement layer and the main part of the reinforcing layer of the carcass reinforcement layer.
• the invention provides that radially outwardly from said point C of the overturning of the carcass reinforcement layer, the overturning of the carcass reinforcement layer and the main part of the carcass reinforcement layer are coupled over a length of between 15 and 65% of the distance between the end of the upturn of the carcass reinforcement layer and the radially innermost point of the circumcircle circle. the bead, to be then decoupled by the first layer of polymer mixture to the end of the upturn of the carcass reinforcement layer.
• the main part of the carcass reinforcement layer and the overturning of the carcass reinforcement layer are said to be decoupled if, radially outside the coupling zone, the thickness of the rubber mixture separating the respective reinforcing elements of the main portion of the carcass reinforcement layer and the overturning of the carcass reinforcement layer is greater than that of the coupling zone.
• the respective reinforcement elements of the main part of the carcass reinforcement layer and the overturning of the carcass reinforcement layer are then advantageously separated by a thickness of rubber compound of between 3 and 8 mm, said thickness of rubber mix being measured in the normal direction to the reinforcing elements of the main portion of the carcass reinforcement layer between the respective reinforcing elements of the main portion of the carcass reinforcement layer and the reversal of the reinforcing layer of the carcass reinforcement layer; carcass.
• the respective reinforcement elements of the main part of the carcass reinforcement layer and the overturning of the carcass reinforcement layer are separated by at most 6 mm and preferably they are separated by at least 4 mm.
• the decoupling zone may consist of a first part, called transition, extending the coupling zone in which the thickness of rubber mixture separating the respective reinforcing elements. of the main part of the carcass reinforcement layer and the reversal of the carcass reinforcement layer increases and a radially outermost second portion in which the thickness of the rubber mixture separating the respective reinforcing elements from the main portion of the carcass reinforcement layer and the overturning of the carcass reinforcement layer; the carcass reinforcement layer is substantially constant.
• the increase in the thickness of the first layer of polymer mixture makes it possible to compensate for the decrease in the tension in the reinforcing elements of the carcass reinforcement when approaching the end of its body. reversal for absorbing shear stresses between the main portion of the carcass reinforcement layer and its overturning.
• the decoupling length is advantageously between 5 and 40% of the distance between the end of the upturn of the carcass reinforcement layer and the radially innermost point of the circle circumscribed to the bead wire and preferably between 15 and 35% of the distance between the end of the upturn of the carcass reinforcement layer and the radially innermost point of the circle circumscribing the bead wire.
• the upturn of the carcass reinforcement layer and the main part of the carcass reinforcement layer are coupled over a length of between 25 and 40% of the distance. between the end of the upturn of the carcass reinforcement layer and the radially innermost point of the circle circumscribing the bead wire.
• the carcass reinforcement layer is formed of reinforcement elements inserted between two polymer mixture calendering layers, said reversal of the carcass reinforcement layer being separated. of the main portion of the carcass reinforcement layer by a first polymeric compound layer extending radially from the bead wire to at least the end of the carcass reinforcement layer overturn and said overturning of the bodyshell layer.
• carcass reinforcement being axially outwardly in contact with a second layer of polymeric mixture, itself at least in contact with a third layer of polymeric mixture forming the outer surface of the tire in the zone bead, said third layer of polymeric mixture being intended in particular to come into contact with the rim, said third layer of polymeric mixture being radially outwardly in contact with a fourth layer of polymeric mixture forming the outer surface of a flank and according to the invention, in a meridian section of said tire, the radially outer end of the first layer of polymeric mixture is radially external to the end of the upturn of the carcass reinforcement layer,
• the end of the upturn of the carcass reinforcement layer is radially external to the radially outer end of the second layer of polymeric mixture
• the radially outer end of the second layer of polymeric mixture is radially external to the radially outer end of the third layer of polymeric mixture
• the distance between the end of the upturn of the carcass reinforcement layer and the radially innermost point of the circle circumscribed by the bead wire is between 45 and 90% of the distance between the axially outermost point Z of the part main part of the carcass reinforcement layer and the radially innermost point of the circle circumscribing the bead wire
• the upturn of the carcass reinforcement layer and the main portion of the carcass reinforcement layer are coupled over a length of between 15 and 65% of the distance between the end of the upturn of the carcass reinforcement layer and the radially innermost point of the circle circumscribed to the bead wire, then to be decoupled by the first layer of mixture polymer to the end of the upturn of the carcass reinforcement layer over a length of between 5 and 40% of the distance between the end of the upturn of the armor layer carcass and the radially innermost point of the circle circumscribing the rod.
• the decoupling zone may consist of a first part, called a transition portion, extending the coupling zone in which the thickness of the rubber mixture separating the respective reinforcing elements from the the main portion of the carcass reinforcement layer and the upturn of the carcass reinforcement layer increases and a second radially outermost portion in which the thickness of the rubber mixture separates the respective reinforcing elements from the portion of the carcass reinforcement layer and the overturning of the carcass reinforcement layer is substantially constant.
• the crown reinforcement comprising at least one layer of reinforcement elements, the ratio of the radial distance between the point axially the the outermost part of the main part of the carcass reinforcement layer and the radially outermost point of the nominal rim, that is the radially outermost point of the rim hook, over the radial distance between the the axially outer end of the reinforcing element layer of the axially widest vertex armature and the radially outermost point of the nominal rim is less than or equal to 55%.
• the ratio of the radial distance between the axially outermost point of the main portion of the carcass reinforcement layer and the radially outermost point of the rim. the radial distance between the axially outer end of the reinforcing element layer of the axially widest vertex armature and the radially outermost point of the nominal rim is less than 53%.
• the more usual designs of this type of tire include a reversal of the carcass reinforcement layer such that the distance between the end of the upturn of the carcass reinforcement layer and the radially innermost point of the circle circumscribing the bead wire is less than 45% of the distance between the axially the outermost part of the main part of the carcass reinforcement layer and the radially innermost point of the circle circumscribing the bead wire, in particular to improve the performance of the tire in terms of endurance.
• the decoupling between the upturn of the carcass reinforcement layer and the main part of the carcass reinforcement layer which follows the coupling zone, according to this second embodiment of the invention, is obtained by a increasing the thickness of the first layer of polymeric mixture.
• This decoupling makes it possible to compensate for the decrease in the tension in the reinforcement elements of the carcass reinforcement when approaching the end of its upturn to absorb the shear stresses between the main part of the strut layer. carcass reinforcement and its overturning.
• the decoupling length is between 15 and 35% of the distance between the end of the upturn of the carcass reinforcement layer and the radially innermost point. from the circle circumscribed to the rod.
• the upturn of the carcass reinforcement layer and the main portion of the carcass reinforcement layer are coupled over a length of between 25 and 40% of the carcass reinforcement layer.
• the distance between the end of the upturn of the carcass reinforcement layer and the radially innermost point of the circle circumscribing the bead wire is radially between the radially outermost point of the circle circumscribing the bead wire. and the radially innermost point of the circle circumscribing the rod.
• the modulus of elasticity under tension at 10% elongation of the calendering layers of the reinforcing layer carcass is between 4 and 16 MPa and preferably between 8 and 12 MPa.
• the modulus of elasticity under tension at 10% elongation of the first polymeric mixture layer is less than or equal to the modulus of elasticity.
• tensile elasticity at 10% elongation of the calender of the carcass reinforcement layer is preferred. This choice makes it possible in particular to concentrate the shearing forces within the first layer of polymer mixture.
• the modulus of elasticity under tension at 10% elongation of the first polymeric mixture layer is greater than 50% of the modulus of elasticity under tension at 10% elongation of the calender of the carcass reinforcement layer and preferably is greater than 70% of the modulus of elasticity under tension at 10% elongation of the calender of the layer of carcass reinforcement. This choice makes it possible to maintain the shear stresses within the first polymeric mixture layer while ensuring good endurance performance.
• the modulus of elasticity under tension at 10% elongation of the second layer The polymer blend is less than 150% of the modulus of elasticity under tension at 10% elongation of the calender of the carcass reinforcement layer.
• the second layer of polymer mixture provides sufficient rigidity to ensure good endurance of the tire during the support on the rim hooks while ensuring satisfactory rolling resistance performance.
• the modulus of elasticity under tension to 10% elongation of the first polymeric mixture layer is greater than or equal to the tensile modulus of elasticity at 10% elongation of the third polymeric mixture layer which is itself greater than or equal to the modulus of elasticity under tension at 10% elongation of the fourth layer of polymeric mixture.
• the carcass reinforcement layer is formed of reinforcing elements inserted between two polymer mixture calendering layers, said reversal of the carcass reinforcement layer being separated. of the main portion of the carcass reinforcement layer by a first polymeric compound layer extending radially from the bead wire to at least the end of the carcass reinforcement layer overturn and said overturning of the bodyshell layer.
• carcass reinforcement being axially outwardly in contact with a second layer of polymeric mixture, itself at least in contact with a third layer of polymeric mixture forming the outer surface of the tire in the region of the bead, said third polymeric mixture layer being intended in particular to come into contact with the rim, said third layer of polymeric mixture being radial outwardly in contact with a fourth layer of polymeric mixture forming the outer surface of a sidewall, and according to the invention, in a meridian section of said tire, the radially outer end of the first polymeric mixture layer is radially external to the end of the upturn of the carcass reinforcement layer, the radially outer end of the second layer of polymeric mixture is radially external to the end of the upturn of the carcass reinforcement layer,
• the distance between the end of the upturn of the carcass reinforcement layer and the radially innermost point of the circle circumscribing the bead wire is between 25 and 40% of the distance between the axially outermost point Z of the part main part of the carcass reinforcement layer and the radially innermost point of the circle circumscribing the bead wire
• said first polymer blend layer has a thickness, measured in the direction normal to the reinforcing elements of the main portion of the carcass reinforcement layer and passing through the end of the upturn of the carcass reinforcement layer between 30 and 60% of the distance between the reinforcing elements of the main portion of the carcass reinforcement layer and the outer surface of the tire measured in the direction of measurement of the thickness of the first layer of polymeric mixture passing through the end of the overturning of the carcass reinforcement layer,
• the ratio of the distance between the reinforcing elements of the main part of the carcass reinforcement layer and the external surface of the tire measured in the said direction of measurement of the thickness of the first layer of polymer mixture passing through the end reversal of the carcass reinforcement layer over the distance between the end of the upturn of the carcass reinforcement layer and the radially innermost point of the circle circumscribing the bead wire is less than 0.5
• the first and second polymeric mixture layers comprise a reinforcing filler constituted by at least one white filler of silica and / or alumina type comprising SiOH and / or AlOH surface functional groups chosen from the group formed by precipitated or fumed silicas; alumina or alumino silicates or modified carbon blacks during or after synthesis,
• the tensile modulus of elasticity at 10% elongation of the first and second polymeric compound layers is lower than the tensile modulus of elasticity at 10% of the calender elongation of the carcass reinforcement layer and greater than or equal to 30% of the modulus of elasticity under tension at 10% elongation of the calender of the carcass reinforcement layer.
• the more usual designs of this type of tire include a reversal of the carcass reinforcement layer whose end is in a relatively thin bead area compared to tires. of more usual design. Indeed, it is customary to design tires with a relatively thick bead at the end of the upturn of the carcass reinforcement layer to increase the distance between the overturning of the carcass reinforcement layer and the main part. of the carcass reinforcement layer, and thus to best limit the shear stresses which are initiated between the main part of the carasse reinforcement layer and its overturning in particular due to the phenomena of déradiassation which appear during the rolling of the pneumatic.
• the inventors have demonstrated that the tires made according to the invention and which have in particular an end of the upturn of the carcass reinforcement layer in a relatively thin area of the bead associated with the relative sizing and positioning of the various elements. components of the tire bead area, allow to lighten the tire and against all odds to maintain properties in terms of endurance satisfactory, or even improve.
• said first and second polymeric mixture layers are elastomeric mixtures based on natural rubber or synthetic polyisoprene with a majority of cis-1 linkages, 4 and optionally at least one other diene elastomer, the natural rubber or the synthetic polyisoprene in case of cutting being present in a a majority rate relative to the level of the other diene elastomer or elastomers used and a reinforcing filler consisting of either a silica and / or alumina type white filler with SiOH and / or AlOH surface functions selected from the group formed by precipitated or pyrogenic silicas, aluminas or aluminosilicates or alternatively carbon blacks in process or after synthesis, having a BET specific surface area of between 30 and 260 m 2 / g employed at a rate of between 20 and 80 phr, and preferably between 30 and 50 phr, either by a cutting
• the silica level on the overall charge rate being greater than 80% and preferably greater than 90%.
• BET specific surface measurement is performed according to the method of BRUNAUER, EMMET and TELLER described in "The Journal of the American Chemical Society", vol. 60, page 309, February 1938, corresponding to standard NFT 45007 of November 1987.
• a coupling agent and / or covering selected from agents known to those skilled in the art.
• preferential coupling agents are sulphurised alkoxysilanes of the bis (3-trialkoxysilylpropyl) polysulfide type, and among these, in particular, bis (3-triethoxysilylpropyl) tetrasulfide marketed by the company DEGUSSA under the Si69 denominations for pure liquid product and X50S for solid product (50/50 by weight blend with N330 black).
• coating agents examples include a fatty alcohol, an alkylalkoxysilane such as hexadecyltrimethoxy or triethoxysilane respectively marketed by DEGUSSA under the names Sil16 and Si166, diphenylguanidine, a polyethylene glycol, a silicone oil which may be modified with OH or alkoxy functions.
• the covering agent and / or coupling agent is used in a weight ratio relative to the filler> at 1/100 and ⁇ at 20/100, and preferably between 2/100 and 15/100 when the clear filler represents the all of the reinforcing filler and between 1/100 and 20/100 when the reinforcing filler is constituted by a cutting of carbon black and clear charge.
• the modified carbon blacks may be mentioned either during the synthesis by addition to the furnace feed oil of a silicon and / or aluminum compound or after the synthesis by adding, to an aqueous suspension of carbon black in a solution of silicate and / or sodium aluminate, an acid so as to at least partially cover the surface of the carbon black of SiOH and / or AlOH functions.
• the hysteresis and cohesion properties are obtained using a precipitated or pyrogenic silica, or a precipitated alumina or even a BET surface area alumino-silicate between 30 and 260 m 2 / g.
• a precipitated or pyrogenic silica or a precipitated alumina or even a BET surface area alumino-silicate between 30 and 260 m 2 / g.
• this type of filler mention may be made of the silicas KS404 from Akzo, Ultrasil VN2 or VN3 and BV3370GR from Degussa, Zeopol 8745 from Huber, Zeosil 175MP or Zeosil 1165MP from Rhodia, HI -SIL 2000 of the PPG Company etc.
• diene elastomers which can be used in a blend with natural rubber or a synthetic polyisoprene with a majority of cis-1,4 linkages
• BR polybutadiene
• SBR styrene-butadiene copolymer
• BIR butadiene-isoprene copolymer
• SBIR styrene-butadiene-isoprene terpolymer
• elastomers may be modified elastomers during polymerization or after polymerization by means of branching agents such as divinylbenzene or starch agents such as carbonates, halogenotins, halosilicons or else by means of functionalising agents leading to grafting on the chain or at the end of the chain of oxygen functions carbonyl, carboxyl or an amino function such as for example by the action of dimethyl or diethylamino benzophenone.
• branching agents such as divinylbenzene or starch agents such as carbonates, halogenotins, halosilicons or else by means of functionalising agents leading to grafting on the chain or at the end of the chain of oxygen functions carbonyl, carboxyl or an amino function such as for example by the action of dimethyl or diethylamino benzophenone.
• the natural rubber or the synthetic polyisoprene is preferably used at a majority rate. and more preferably at a rate greater than 70 phr.
• Said first and second polymeric mixture layers thus constituted according to this third embodiment of the invention confer superior rigidities to the more usual designs which make it possible to provide the tire bead zones with satisfactory bending stiffnesses in combination with the thicknesses of these areas which are reduced compared to those of more usual tires.
• Said first and second polymeric mixture layers thus constituted according to this third embodiment of the invention still have properties in terms of cohesion and thus resistance to cracking improved in comparison with more usual designs.
• the endurance properties of the areas of the beads of the tire are thus further strengthened.
• a cohesive rubbery mixture is a rubbery mixture particularly resistant to cracking.
• the cohesion of a mixture is thus evaluated by a fatigue cracking test performed on a specimen "PS" (pure shear). It consists in determining, after notching the test piece, the crack propagation speed "Vp" (nm / cycle) as a function of the energy release rate "E” (J / m 2).
• the experimental area covered by the measurement is in the range -20 ° C and + 150 ° C in temperature, with an air or nitrogen atmosphere.
• the biasing of the specimen is a dynamic displacement imposed amplitude ranging between 0.1mm and 10mm in the form of impulse-type stress (tangential "haversine" signal) with a rest time equal to the duration of the pulse; the frequency of the signal is of the order of 10 Hz on average.
• the measurement comprises 3 parts:
• the modulus of elasticity under tension at 10% elongation of the calendering layers of the carcass reinforcement layer is between 4 and 16 MPa and preferably between 8 and 12 MPa.
• the radially inner end of the second polymeric mixture layer is radially between the radially outermost point of the circle circumscribing the rod and the radially innermost point. from the circle circumscribed to the rod.
• This positioning is determined on a section of a tire, the spacing of the beads is the same as when the tire is mounted on the mounting rim recommended by the ETRTO, it being neither mounted nor inflated.
• the tire in any meridian plane, in each bead, the tire comprises a compression frame surrounding the rod and a rubber mix volume directly in contact with the rod.
• the rods are bundles bundles, that is to say rods formed of an assembly of gummed son wrapped around a shape, preferably of hexagonal shape.
• the carcass reinforcement is formed of cables whose structure is strongly penetrated by polymeric mixtures. They may for example be cables whose construction makes it possible to increase their penetrability by the polymeric mixtures. It can also be cables in which polymeric mixtures are inserted during the manufacture of the cables themselves. This is for example of cables with at least two layers, at least one inner layer being sheathed with a layer consisting of a non-crosslinkable, crosslinkable or crosslinked rubber composition, preferably based on at least one elastomer diene.
• the crown reinforcement of the tire is formed of at least two working crown layers of inextensible reinforcement elements, crossed from one layer to the other by making with the circumferential direction angles between 10 ° and 45 °.
• the crown reinforcement further comprises at least one layer of circumferential reinforcing elements.
• a preferred embodiment of the invention further provides that the crown reinforcement is completed radially outwardly by at least one additional layer, called protective layer, of so-called elastic reinforcing elements, oriented relative to the direction. circumferential with an angle between 10 ° and 45 ° and in the same direction as the angle formed by the inextensible elements of the working layer which is radially adjacent thereto.
• the protective layer may have an axial width smaller than the axial width of the least wide working layer.
• Said protective layer may also have an axial width greater than the axial width of the narrower working layer, such that it covers the edges of the narrower working layer and, in the case of the radially upper layer, being the smallest, as coupled, in the axial extension of the additional reinforcement, with the widest working crown layer over an axial width, to be then, axially outside, decoupled from said widest working layer by profiles of thickness at least equal to 2 mm.
• the protective layer formed of elastic reinforcing elements may, in the case mentioned above, be on the one hand possibly decoupled from the edges of said least wide working layer by profiles of thickness substantially less than the thickness. profiles separating the edges of the two working layers, and have on the other hand an axial width less than or greater than the axial width of the widest vertex layer.
• the crown reinforcement can be further completed, radially inwardly between the carcass reinforcement and the nearest radially inner working layer. of said carcass reinforcement, by a triangulation layer of steel non-extensible reinforcing elements making, with the circumferential direction, an angle greater than 60 ° and in the same direction as that of the angle formed by the reinforcing elements of the layer radially closest to the carcass reinforcement.
• FIGS. 1 to 5 represent: FIG. 1, a meridian view of a diagram of a tire according to a first variant embodiment of the invention, FIG. 2, an enlarged schematic representation of the outer surface of the tire between the zone of the bead and the point E, FIG. 3, an enlarged schematic representation of the zone of the bead. according to the first embodiment of the invention of Figure 1, Figure 4, an enlarged schematic representation of the area of a bead according to a second embodiment of the invention, Figure 5, an enlarged schematic representation of the area a bead of a reference tire.
• the figures are not shown in scale to simplify understanding.
• the tire 1 is of dimension 12 R 22.5.
• Said tire 1 comprises a radial carcass reinforcement 2 anchored in two beads 3.
• the carcass reinforcement 2 is hooped at the top of the tire by a crown reinforcement 5, itself capped with a tread.
• the carcass reinforcement 2 formed of a single layer of metal cables, is wound in each of the beads 3 around a rod 4a, 4b and forms in each of the beads 3 a reversal 7 of the layer of carcass reinforcement having one end 8.
• the carcass reinforcement 2 consists of reinforcement elements between two calendering layers whose modulus of elasticity under tension at 10% elongation is equal to 9.8 MPa.
• the reinforcement elements of the carcass reinforcement 2 are 19.18 cables whose elongation at break is equal to 2.5%.
• the carcass reinforcement cables of the tire 1 are cables with structure layer 1 + 6 + 12, not shrunk, consisting of a central core formed of a wire, an intermediate layer formed of six wires. and an outer layer of twelve wires.
• Figure 1 illustrates the tire mounted on its nominal rim J; the axially outermost point Z of the main part of the carcass reinforcement layer 2 is thus determined, the tire being inflated to its nominal pressure, for example by tomography.
• the point E is defined by the projection in the axial direction on the outer surface of the tire of point Z.
• the point F is defined by the intersection between the outer surface of the tire and the straight line, parallel to the axis of rotation, passing by the point I, radially the outermost of the rim J.
• FIG. 2 schematically illustrates the outer surface S of the tire between the points E and F on a meridian section of the tire, defined so that the barycenters 6a, 6b of the rods 4a, 4b form an axially oriented straight line, said 6c, 6b being spaced from each other by a distance equal to the width of the nominal rim J increased by 20 mm and reduced by twice the distance measured axially between a barycentre 6a, 6b of a bead wire 4a , 4b and a point on the outer surface of the tire.
• any point of the profile of the outer surface S of the tire between the points F and E is at a distance less than 0.45 mm from a spline P connecting said first and second points F and E, the tangent T PE of said spline P, passing through the point E forming an angle ⁇ 3 ⁇ 4 with the radial direction equal to 2.8 °, the tangent T PF of said spline P, passing through the point F forming an angle (with the radial direction equal to 9.6 °, the voltage t F at the point F worth 1.5 and the voltage t E at the point E equaling 1.75
• the coordinates of the points of said spline P, in the direct reference formed by the line D connecting the points F and E, of length K equal to 96.5 mm, and its perpendicular G passing through said point F given by:
• FIG. 3 illustrates in an enlarged manner a schematic representation in section of a bead 3 of the tire 1, in accordance with the first variant presented above, in which there is a portion of the carcass reinforcement layer 2 wound around a bead wire 4 to form an upturn 7 with an end 8.
• the radially outermost point B of the circle T is also determined.
• the distance dz between the point Z and the point A is equal to 128 mm.
• the distance d R between the point 8 and the point A is equal to 90 mm.
• the ratio of the distance d R over the distance d z is 70% and therefore between 45 and 90%.
• the radial distance dcj between the axially outermost point of the main portion of the carcass reinforcement layer and the radially outermost point of the nominal rim is equal to 108.2 mm.
• the radial distance dsj between the axially outer end of the reinforcing element layer of the axially widest vertex reinforcement and the radially outermost point of the nominal rim is equal to 206.7 mm.
• the ratio of the distance d C j over the distance d S j is equal to 52.3% and therefore less than 53%.
• the upturn 7 of the carcass reinforcement layer is coupled to the main part of the carcass reinforcement layer 2 from the point C, such that the distance between the point C and the point A is equal to 37 mm.
• the ratio of the distance d c over the distance d R is equal to 41% and therefore between 30 and 55%.
• the upturn 7 of the carcass reinforcement layer is then decoupled from the main part of the carcass reinforcement layer 2 from the point D, such that the distance d D between the point D and the point A is equal to 66 mm and such that the coupling length between the point C and the point D is equal to 29 mm and therefore between 25 and 40% of the distance d R.
• the coupling length is measured along the straight line through points C and D.
• the coupling thickness between the main portion of the carcass reinforcement layer 2 and the upturn 7 of the carcass reinforcement layer, measured in the normal direction to the reinforcing elements of the main part of the layer of carcass reinforcement 2 between the respective reinforcement elements of the main part of the carcass reinforcement layer and the upturn of the carcass reinforcement layer, is substantially constant and equal to 2.9 mm.
• the decoupling length between point D and point 8 is equal to 21 mm and therefore between 15 and 35% of the distance d R.
• the decoupling length is measured along the line through points D and 8.
• the upturn 7 of the carcass reinforcement layer is separated from the carcass reinforcement 2 by a first polymeric mixture layer 9, having a radially outer end 10 at a dio distance from the point A equal to 117 mm.
• the first polymeric mixture layer 9 has a tensile modulus of elasticity at 10% elongation equal to 7.8 MPa and therefore less than the tensile modulus of elasticity at 10% elongation of the calendering layers of the reinforcement. carcass 2.
• the first polymeric mixing layer 9 is profiled to bear on the rod 4 and ensure the coupling and decoupling between the overturning of the carcass reinforcement layer 7 and the main portion of the carcass reinforcement layer. 2.
• Axially outside the upturn 7 of the carcass reinforcement layer is represented the second polymeric mixture layer 11, the radially outer end 12 of which is radially inside the end 8 of the upturn 7. the carcass reinforcement layer.
• the radially inner end 13 of the second polymeric mixture layer 11 is radially between the points A and B, respectively radially the innermost and radially the outermost of the circle circumscribing the bead wire.
• the second layer of polymeric mixture 11 has a modulus of elasticity under tension at 10% elongation equal to 12.5 MPa and therefore greater than the modulus of elasticity under tension at 10% elongation of the calendering layers of the carcass reinforcement 2.
• the third layer of polymeric mixture 14 In contact with the second layer of polymeric mixture 11 and radially under the bead wire, there is the third layer of polymeric mixture 14, the axially outermost end 15 of which is radially inside the end 12 of the second polymeric mixture layer 11.
• the third polymeric mixture layer 14 has a modulus of elasticity under tension at 10% elongation equal to 7.1 MPa.
• the end 17 radially inner of the fourth layer of polymeric mixture 16 is radially inner to the end 15 of the third layer of polymeric mixture 14.
• the fourth layer of polymeric mixture 16 has a tensile modulus of elasticity at 10% elongation equal to 3.1 MPa.
• FIG. 4 illustrates, in an enlarged manner, a schematic representation in section of a bead 3, of another embodiment of a tire according to the third variant of the invention presented above, in which a part the carcass reinforcement layer 2 wound around a bead wire 4 to form an upturn 7 with an end 8.
• the axially outermost point Z of the main portion of the carcass reinforcement layer 2 is materialized; it is determined for example by tomography, the tire being inflated to its nominal pressure.
• the radially outermost point B of the circle T is also determined.
• the distance dz between the point Z and the point A is equal to 128 mm.
• the distance dR between the point 8 and the point A is equal to 44 mm.
• the ratio of the distance d R over the distance d z is equal to 34% and therefore between 25 and 40%.
• the upturn 7 of the carcass reinforcement layer is separated from the main part of the carcass reinforcement layer 2 by a first layer of polymeric mixture 9, having a radially outer end 10 at a distance dio from the point A equal to 105 mm.
• the first polymeric mixture layer 9 has an elastic modulus under tension at 10% elongation equal to 5 MPa and therefore less than the modulus of elasticity under tension at 10% elongation of the calendering layers of the reinforcing armature. carcass 2.
• Axially on the outside of the upturn 7 of the carcass reinforcement layer is represented the second layer of polymeric mixture 11, the radially outer end 12 of which is radially outwardly of the end 8 of the upturn 7. the carcass reinforcement layer at a distance of from point A equal to 112 mm.
• the radially inner end 13 of the second polymeric mixture layer 11 is radially between the points A and B, respectively radially the innermost and radially the outermost of the circle circumscribing the bead wire.
• the second layer of polymeric mixture 11 has a modulus of elasticity under tension at 10% elongation equal to 5 MPa and therefore less than the modulus of elasticity under tension at 10% elongation of the calendering layers of the carcass reinforcement 2.
• the third layer of polymeric mixture 14 has a modulus of elasticity under tension at 10% elongation equal to 7.1 MPa.
• the radially inner end 17 of the fourth layer of polymeric mixture 16 is radially at the end of the third layer of polymeric mixture 14.
• the fourth layer of polymeric mixture 16 has a modulus of elasticity under tension at 10% elongation equal to 3.1 MPa.
• the first layer of polymeric mixture 9 has a thickness Ei, measured in the normal direction to the reinforcing elements of the main part of the carcass reinforcement layer and passing through the end of the upturn of the reinforcing layer. carcass equal to 7.5 mm.
• the distance E 2 between the reinforcing elements of the main part of the carcass reinforcement layer and the external surface of the tire measured according to the measurement direction of the thickness Ei of the first polymeric mixture layer passing through the end of the upturn of the carcass reinforcement layer is equal to 20 mm.
• the ratio of the thickness Ei of the first layer 9 of polymer mixture over the distance E 2 , measured between the reinforcing elements of the main part of the carcass reinforcement layer and the external surface of the tire, is equal to 38% and therefore between 30 and 60%.
• the ratio of the distance E 2 , measured between the reinforcing elements of the main part of the carcass reinforcement layer and the external surface of the tire, over the distance dR between the end of the upturn of the protective layer. carcass reinforcement and the radially innermost point of the circle circumscribing the rod is equal to 0.45 and therefore less than 0.5.
• Endurance tests were carried out by rolling two planed tires on one another with a regulated pressure of 5.5b, and a load of 4571 daN at a speed of 50km / h and at an ambient temperature. 15 ° C during 20000 km.
• the tires according to the invention are compared with reference tires RI and R2.
• the tires RI an enlarged schematic representation of the region of the bead is shown in Figure 5, are tires of conventional design having stiffeners 18 and areas of the usual beads with in particular a greater bead thickness, with in particular a distance d R between the end 8 of the upturn 7 of the carcass reinforcement layer 2 and the radially innermost point A of the circle T circumscribed at the bead wire 4 equal to 37% of the distance dz between the point axially the outermost Z of the main portion of the carcass reinforcement layer and the radially innermost point A of the circle T circumscribing the bead wire and first and second polymeric mixture layers 9 and 11, the modulus of elasticity of which under tension at 10% elongation is equal to 3.7 MPa.
• the tires R2 differ from the tires RI by the absence of stiffener 18.
• the lost volume is measured in the tire area which comes into contact with the rim using a laser profilometer. And we check on meridian cuts if cracks appeared in the tire area radially inside the point E.

Landscapes

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

Applications Claiming Priority (2)

Publications (1)

Family

ID=56920819

Family Applications (1)

Country Status (2)

Families Citing this family (4)

Family Cites Families (12)

• 2017
  • 2017-07-11 WO PCT/FR2017/051892 patent/WO2018011509A1/fr unknown
  • 2017-07-11 EP EP17748533.1A patent/EP3484725A1/de not_active Withdrawn

Also Published As

Similar Documents

Legal Events