WO2003093033A1 - Tyre with bead provided with a zone facilitating mounting/dismounting - Google Patents

Tyre with bead provided with a zone facilitating mounting/dismounting Download PDF

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Publication number
WO2003093033A1
WO2003093033A1 PCT/EP2003/004418 EP0304418W WO03093033A1 WO 2003093033 A1 WO2003093033 A1 WO 2003093033A1 EP 0304418 W EP0304418 W EP 0304418W WO 03093033 A1 WO03093033 A1 WO 03093033A1
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WO
WIPO (PCT)
Prior art keywords
zone
bead
tire
radially
anchoring
Prior art date
Application number
PCT/EP2003/004418
Other languages
French (fr)
Inventor
Pascal Auxerre
Original Assignee
Societe De Technologie Michelin
Michelin Recherche Et Techniques S.A.
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by Societe De Technologie Michelin, Michelin Recherche Et Techniques S.A. filed Critical Societe De Technologie Michelin
Priority to AU2003227686A priority Critical patent/AU2003227686A1/en
Publication of WO2003093033A1 publication Critical patent/WO2003093033A1/en

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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
    • B60C15/06—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
    • B60C15/0009—Tyre beads, e.g. ply turn-up or overlap features of the carcass terminal portion
    • B60C15/0018—Tyre beads, e.g. ply turn-up or overlap features of the carcass terminal portion not folded around the bead core, e.g. floating or down ply
    • 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
    • B60C15/02—Seating or securing beads on rims
    • B60C15/0236—Asymmetric bead seats, e.g. different bead diameter or inclination angle
    • 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
    • B60C15/02—Seating or securing beads on rims
    • B60C15/024—Bead contour, e.g. lips, grooves, or ribs
    • 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
    • B60C3/06—Tyres characterised by the transverse section asymmetric
    • 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
    • B60C9/0207—Carcasses comprising an interrupted ply, i.e. where the carcass ply does not continuously extend from bead to bead but is interrupted, e.g. at the belt area, into two or more portions of the same ply

Definitions

  • the present invention relates to a tire for a vehicle wheel in which at least one of the beads has a seat with a generator whose axially inner end is on a circle with a diameter greater than the diameter of the circle on which the axially outer end is located.
  • This type of design is particularly suitable for new generations of tires which can be used, within certain limits, in conditions of low pressure, or even zero or almost zero pressure, with an elimination of the risk of the tire becoming detached from the rim on which it is mounted. This concept is often referred to as "extended mobility".
  • the function of tightening the tire on the rim is an essential function for ensuring the qualities of the tire in operation. Indeed, it acts directly or indirectly on multiple aspects such as mounting (sometimes called “clipping") or fixing the tire, sealing the tire, rotation on the rim, etc. These functions are all critical and require specific characteristics and rigorous manufacturing of the products, in particular if high quality standards are sought. out, rims and tires often have slightly different dimensions for the same code, mainly due to manufacturing tolerances. These dimensional variations complicate compliance with the various functions previously listed.
  • the conventional rod is replaced by an anchoring zone comprising in particular arrangements of circumferential wires cooperating with the carcass-type reinforcement structure via an anchoring or binding mixture.
  • the anchoring area provides all of the functions presented above.
  • Document EP 0 582 196 presents a tire comprising a tread extended by two sidewalls and two beads as well as a carcass anchored in the two beads with an annular reinforcement.
  • the carcass is made up of threads placed adjacent to each other, circumferentially aligned and in contact with at least one layer of bonding rubber of very high elastic modulus in the attachment zone of the bead comprising the annular reinforcement.
  • the annular reinforcement of the bead attachment zone consists of stacks of circumferential cords with interposition between the reinforcing cords of the carcass and these stacks of a layer of bonding rubber of very high elasticity modulus .
  • This embodiment is intended for tires of the conventional type, with retention of the beads against the rim hook due to the inflation pressure of the tire. pneumatic.
  • a predominance of lateral or axial type forces inducing significant compressive forces acting substantially axially from the walls towards the center of said bead. These forces increase as a function of the inflation pressure. The increase in pressure tends to slide the bead against the hook, radially outward. The forces induced radially inwards against the seat of the rim decrease with increasing pressure, or with any increase in tension in the carcass-type reinforcing structure.
  • the stacks of son are aligned in a direction substantially parallel to the orientation of the profile of the rim hook against which the bead is supported.
  • the profile of the bead of this type of tire is relatively narrow and elongated; the anchor is distributed over most of the height and width of the bead.
  • the passage of the carcass in the bead is generally substantially central with respect to the walls of said bead.
  • Document EP 0 673 324 describes a rolling assembly comprising at least one tire with a radial carcass reinforcement anchored in each bead and a rim of particular shape.
  • This rim has a first seat with a generator such that the axially outer end of said generator is distant from the axis of rotation by a length less than the distance separating its axially inner end and is delimited axially on the outside by a rim protrusion or rim.
  • the tire includes bead seats suitable for mounting on this rim.
  • the type of pneumatic / rim interface proposed in this document has many advantages compared to already known solutions, in particular in terms of ease of assembly / disassembly while allowing a certain distance to be made despite a pressure drop.
  • the document EP 0 748 287 describes a solution allowing a first optimization of the basic technology described in the document EP 0 673 324 previously cited. It is a tire of which at least one bead has a structure making it possible to modify the tightening of said bead as a function of the tension of the carcass reinforcement and in particular a reinforcement thereof when the inflation pressure increases. up to its nominal value.
  • the document thus proposes the use of a bead with anchoring of the end of the carcass by turning it around the base of the rod, by the axially and radially inner sides with respect to the rod.
  • the bead also comprises, adjacent to the rod and axially outside of the latter, a rubber mixture profile of relatively high hardness against which the rod can come to exert a compressive force during an increase in tension of the carcass reinforcement.
  • This compressive force creates a self-tightening of the tip of the bead on the mounting rim.
  • the tension of the carcass therefore causes the rod to move outward, so that the latter generates said compressive force.
  • the presence of a rod of the conventional type and the inversion of the carcass under the latter are presented as being essential for generating the compressive force. This limits the possibilities of considering other types of arrangement.
  • document EP 0 922 592 describes two embodiments with anchoring of the carcass by turning it axially outwards.
  • the first mode proposes an anchoring of the carcass in the bead by turning radially outward from the end of the carcass.
  • the upturn is surrounded on either side by two radially superposed layers of metal wires arranged axially side by side and covering substantially the entire axial portion along the seat of the bead.
  • the layers are arranged so as to be parallel to the seat.
  • the types of wires and the corresponding dimensions are very precise.
  • the second proposed solution in this document relates to bead seats with different diameters.
  • the carcass is also stowed differently than the first solution.
  • the carcass is subdivided into two radially separated portions at the level of the bead. Each portion is joined by a layer of wires arranged radially, each layer being disposed radially outwardly against each of the carcass portions.
  • the radially outer carcass portion and the layer of wires radially inside are separated by an elastomer type insert of high hardness provided in the bead. This insert axially lines the central portion of the bead and rises radially outwards and axially inwards, beyond the radial limit of presence of the metallic wires.
  • the carcass is subdivided into two portions and a high hardness insert is necessary to separate on the one hand the layers of wires and on the other hand the two carcass portions.
  • the carcass is not anchored in the insert.
  • the shape of the insert described is limiting.
  • the present invention therefore proposes to overcome the various drawbacks inherent in the solutions set out above.
  • a tire for a vehicle wheel comprising:
  • each bead comprising a seat and an external flange intended to come into contact with a suitable rim
  • a bead seat comprising a generator whose axially inner end is on a circle of diameter greater than the diameter of the circle on which the axially outer end is located;
  • a zone for anchoring the reinforcement structure in said bead comprising a substantially radial arrangement of circumferential wires disposed substantially adjacent to a portion of the reinforcement structure and comprising at least two stacks distributed on either side of the reinforcement structure, a connection mixture being arranged between the circumferential wires and the reinforcement structure;
  • an “assembly / disassembly” zone disposed substantially adjacent to the seat of the bead, radially inside the anchoring zone, and the distance of which corresponds substantially to the distance BS-BC, where BS is the base of the seat and BC is the rim hook base.
  • This zone corresponding substantially to the zone most requested during mounting / dismounting operations, aims to facilitate or optimize the mounting / dismounting of the tire on the associated rim.
  • This area is therefore slightly deformable, in particular during assembly or disassembly, in particular when passing over the rim hook. It is also enduring, to undergo repeated cycles of assembly / disassembly, without deterioration special.
  • the bead further comprises:
  • An intermediate zone arranged substantially axially outside the anchoring zone and comprising at least one portion substantially aligned radially with the anchoring zone;
  • a support zone of said bead capable of resting directly or indirectly against the adapted rim seat, and comprising at least one portion axially aligned with the intermediate zone and radially internal to this zone;
  • Such a configuration allows optimal retention of the bead in the rim, in particular at the level of the rim seat / bead seat interface.
  • the forces acting on the anchoring zone are then well transmitted to the zone of the seat of the bead.
  • the radial continuity makes it possible to minimize the impact of the shearing forces acting against the bead as a whole.
  • the assembly / disassembly zone forms an extension radially inside the anchoring zone.
  • the material of the assembly-disassembly zone preferably comprises a module substantially smaller than that of the material of the support zone.
  • the anchoring zone does not comprise a rod, in particular a rod of the traditional type, such as for example a multi-wire rod against which a carcass ply is turned over, so that the zone of cooperation between the inverted portion of ply and the rod provides support for the carcass ply.
  • a rod of the traditional type such as for example a multi-wire rod against which a carcass ply is turned over
  • Each of the zones taken in isolation as well as all of the zones form a sort of internal bead capable of effecting relative movements, such as for example of angular or rotating type, with respect to another zone, or with respect to a virtual CP pressure center, or relative to the rim seat, etc.
  • the intermediate zone provides a mechanical connection between said anchoring zone and said support zone.
  • the intermediate zone provides continuity between the two other zones, so that the mechanical forces are transmitted from the anchoring zone to the support zone.
  • the intermediate zone is likely to exert a force substantially radially inwards against the axially external portion of the support zone.
  • the intermediate zone provides a mechanical connection between said anchoring zone and said support zone.
  • the anchoring zone and the intermediate zone can be mechanically combined. It is the same for the intermediate zone which can be joined to the support zone.
  • the anchoring zone is preferably not directly joined to the support zone.
  • said support zone is substantially elongated. It extends for example substantially along the seat of the bead.
  • the transfer of forces during the rotation of the lower zone of the axially internal portion towards the axially external portion is thus possible, while retaining support against at least a portion of the seat of the bead.
  • the transfer of forces ensures self-tightening of the tip of the bead against the rim.
  • the support zone is substantially constituted by a mixture of high modulus rubber.
  • the shape gives the tire during manufacture a shape substantially similar to the shape of the finished product, the elimination of turning (which exists with a traditional architecture) allows an advantageous simplification of manufacturing.
  • the bases of the piles are arranged radially more outside than the end of said rim (portion axially and radially outermost of said edge).
  • the bases of the stacks are advantageously provided so as to be arranged radially outwardly relative to the rim of the rim adapted to the tire. The assembly / disassembly operations are then facilitated.
  • the carcass-type reinforcement structure extends substantially radially from each of the beads, along the sides, towards the crown zone.
  • Said structure can thus be unitary and extend from one bead to another, or even be divided into two half-structures, each extending along a single flank.
  • the number of stacks as well as the number of windings or turns of each of the stacks is advantageously established as a function of the characteristics sought for the tire, for example its operating pressure. For example, a higher number of stacks may be desired in order to increase the rigidity at the bead area.
  • the carcass-type reinforcement structure preferably consists of a wire winding going back and forth between the two, beads forming loops in each of the beads. Furthermore, the wire winding preferably consists of a single wire.
  • FIG. 1 illustrates, in cross section, a tire according to the invention
  • FIG. 2 illustrates, in enlarged cross-section, a bead of a first variant of a tire according to the invention
  • Figure 3 illustrates, in enlarged cross section, another variant of beads, where the different areas of . bead are arranged advantageously.
  • the reinforcement or reinforcement of tires is currently - and most often - constituted by stacking one or more plies conventionally designated “carcass plies”, “crown plies”, etc.
  • This way of designating the reinforcing reinforcements comes from the manufacturing process, consisting in producing a series of semi-finished products in the form of plies, provided with wire reinforcements often longitudinal, which are then assembled or stacked in order to make a blank of pneumatic.
  • the sheets are made flat, with large dimensions, and are then cut according to the dimensions of a given product.
  • the plies are also assembled, initially, substantially flat.
  • the blank thus produced is then shaped to adopt the toroidal profile typical of tires.
  • the semi-finished products called "finishing" are then applied to the blank, to obtain a product ready for vulcanization.
  • Such a “conventional” method involves, in particular for the manufacturing phase of the tire blank, the use of an anchoring element (generally a bead wire), used to anchor or maintain the carcass reinforcement in the area of the tire beads.
  • an anchoring element generally a bead wire
  • a portion of all the plies making up the carcass reinforcement is turned around a bead wire disposed in the bead of the tire. This creates an anchoring of the carcass reinforcement in the bead.
  • the tires described in this document do not have the "traditional" turning of the carcass ply around a bead wire.
  • This type of anchoring is replaced by an arrangement in which there is disposed adjacent to said flank reinforcement structure of the circumferential filaments, the whole being embedded in a rubber mixture of anchoring or binding.
  • the conventional terms such as “tablecloths”, “rods”, etc.
  • the term “carcass-type reinforcement” or “sidewall reinforcement” is valid for designating the reinforcing threads of a carcass ply in the conventional process, and the corresponding threads, generally applied at the flanks, of a tire produced using a semi-finished process.
  • anchoring zone for its part, can designate the “traditional” turning of the carcass ply around a rod of a conventional process just as much as the assembly formed by the circumferential filaments, the rubber mixture and the adjacent flank reinforcement portions of a lower zone produced with a method with application to a toroidal core.
  • the term “thread” generally designates both monofilaments and multifilaments or assemblies such as cables, twists or any other equivalent type of assembly, regardless of the material and the treatment. of these sons. It may for example be surface treatments, coating or pre-sizing to promote adhesion to the rubber.
  • unitary wire designates a wire composed of a single element, without assembly.
  • multifilaments designates an assembly of at least two unitary elements to form a cable, a twist, etc.
  • radial structure is meant an arrangement at 90 degrees, but also, depending on usage, at an angle close to 90 °.
  • the carcass ply (s) are turned around around a rod.
  • the rod fulfills a function of anchoring the carcass.
  • it supports the tension developing in the wires of carcass for example under the effect of inflation pressure.
  • the arrangement described in this document ensures a similar anchoring function. It is also known to use the rod of the traditional type to ensure a function of tightening the bead on a rim. The arrangement described in this document also ensures a similar tightening role.
  • the term "gum” or “bonding” mixture is understood to mean the rubber mixture possibly in contact with the reinforcing wires, adhering to them and capable of filling the interstices between adjacent wires.
  • contact between a wire and a layer of bonding rubber means that at least part of the outer circumference of the wire is in intimate contact with the rubber mixture constituting the bonding rubber.
  • the sidewalls are the portions of the tire most often of low bending stiffness located between the crown and the beads.
  • “Sidewall mixes” are rubber mixes located axially outwardly relative to the wires of the carcass reinforcement structure and to their bonding rubber. These mixtures usually have a low modulus of elasticity.
  • module of elasticity of a rubber mixture is understood to mean a secant extension module obtained at a uniaxial extension deformation of the order of 10% at ambient temperature.
  • FIG. 1 illustrates, in cross section, a tire 1 according to the invention.
  • This tire comprises a first sidewall 5 adjacent to a first bead 3 preferably corresponding to the inner bead.
  • the opposite portion of the tire comprises a second sidewall 6 adjacent to a second bead 4.
  • a crown 7, on which a tread 8 is provided, provides the junction between the sidewalls.
  • the top preferably includes at least one reinforcing belt.
  • the tire comprises a carcass-type reinforcement structure 2, provided with reinforcements advantageously configured in a substantially radial arrangement. This structure can be arranged continuously from one bead to the other, passing through the sides and the top, or it can comprise two or more parts, arranged for example along the sides, without covering the entire Mountain peak.
  • the end portions of the reinforcing structure 2 are located in the beads.
  • the reinforcing structure 2 can be produced by winding a single wire going back and forth between the two beads, forming loops in each of the beads. These loops, coated in the rubber mixture, contribute to the mechanical connection between the reinforcement structure 2 and the bead, in particular the piles 13. By the presence of loops between the "outward” course and the "return” of the wire, we see that the reinforcement is of the monofilament type. Of course, the carcass might not be made continuously from a single wire, and there might not be loops, but for example cut ends.
  • the bead further comprises an anchoring zone 30 comprising an arrangement of circumferential wires disposed substantially adjacent to a portion of the reinforcement structure and comprises at least two stacks distributed on either side of the reinforcement structure, a bonding (or anchoring) mixture being disposed between the circumferential wires and the reinforcing structure.
  • an anchoring zone 30 comprising an arrangement of circumferential wires disposed substantially adjacent to a portion of the reinforcement structure and comprises at least two stacks distributed on either side of the reinforcement structure, a bonding (or anchoring) mixture being disposed between the circumferential wires and the reinforcing structure.
  • At least one wire 12 from one of the stacks 13 is preferably placed in the immediate vicinity of a portion 21 of the reinforcing structure 2.
  • the stacks can also be arranged so that a portion 21 is interposed between batteries 13.
  • the space between the wires 12 and the reinforcement structure 2 is occupied by a rubber bonding mixture14. It is also possible to provide for the use of several mixtures having different characteristics, delimiting several zones, the combinations of mixtures and the resulting layouts being almost unlimited. According to an advantageous variant, provision is made for the presence of a rubber mixture with a substantially high modulus of elasticity in the area of intersection between the arrangement of wires 11 and the reinforcement structure 2. By way of nonlimiting example, the modulus of elasticity of such . gum can reach 10 to 20 and even exceed 40 Mpa.
  • the wire arrangements 11 can be arranged and manufactured differently.
  • a battery 13 can advantageously consist of a single wire 12, wound (substantially at zero degrees) in a spiral, preferably from the smallest diameter to the largest diameter.
  • a pile can also consist of several concentric wires laid one inside the other.
  • the anchoring of the reinforcing structure in the bead can be achieved by the type of interface described, despite the fact that in the tire with extended mobility according to the invention, the forces induced at the level of the bead differ from those of a conventional bead.
  • an increase in pressure causes an increase in the radial thrust of the radially outer portion of the seat of the bead against the seat of the rim.
  • Figures 2 and 3 illustrate different examples of arrangements of the other zones of the bead.
  • a support zone 50 is provided Radially inside the anchoring zone, or more particularly in the radially internal portion of the bead, in the seat zone. This area acts as an interface between the rest of the bead and the seat of the rim. Significant efforts of the radial type. and axial are therefore transmitted by this zone.
  • a high modulus rubber mixture contributes to the transfer of these forces by ensuring good retention of the bead against the rim.
  • an intermediate zone 40 is advantageously provided, so as to ensure mechanical continuity. The forces can thus be transmitted from the anchoring zone 30 to the support zone 50, via the zone intermediate 40.
  • the three zones can also be joined, to form a unified whole as illustrated for example in FIG. 2.
  • An “assembly / disassembly” zone 70 is arranged substantially adjacent to the seat of the bead, radially inside the anchoring zone. It extends substantially radially from between the points or dimensions BS-BC, where BS is the base of the seat and BC is the base of the rim hook. The area 70 therefore has a sort of "height" corresponding substantially to the distance between BS and BC.
  • This zone aims at facilitating / optimizing the mounting / dismounting of the tire on the associated rim, in particular by conferring a certain flexibility on one of the areas most requested during mounting or dismounting operations of the tire.
  • the “assembly / disassembly” zone is arranged substantially axially internally to the support zone.
  • the assembly / disassembly zone forms an extension radially inside the anchoring zone.
  • the material of the assembly-disassembly zone preferably comprises a module substantially smaller than that of the material of the support zone.
  • the tire according to the invention is particularly suitable for use on a rim of the type described in document EP 0 673 324.
  • a rim comprises a seat and preferably a raising or rim located axially and radially outward.
  • the quality of contact or support of the bead on the seat is particularly important.
  • One of the means according to the invention used to improve it consists in optimizing the previously described phenomenon of rotation of the lower zone of the bead.
  • This phenomenon stems from the structure of the bead used.
  • the axial position of the reinforcement structure 2 relative to the center of thrust CP of the bead can, to a certain extent, influence the moment M created by a tension force T induced in the reinforcement structure. This moment M acts on the effect of rotation of the lower zone of the bead.
  • a buffer zone is provided on the bead between the high modulus mixing zone and the rim flange.
  • This crushing zone 17 is made of a more flexible material than that generally located in the interface zone between the arrangement 11 of wires and the reinforcement structure 2. As previously described, under the combined effect of the pressure of the tire and of a tension T acting on the structure 2, the moment M thus created acts so as to crush the zone 17, thereby favoring the rotation of the lower zone of the bead.

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

Abstract

The invention concerns a vehicle tyre, comprising two sidewalls assembled through a crown zone, beads, a reinforcing structure extending substantially radially from each of the beads, along the sidewalls, towards the crown zone, at least one of said beads comprising: a bead seat (10) having a generatrix whereof the axially inner end is on a circle of diameter greater than the diameter of the circle whereon lies the axially outer end; a zone anchoring (30) the reinforcing structure in said bead; an intermediate zone (40), arranged substantially axially on the outside relative to the anchoring zone; a support zone (50) for said bead capable of being set directly or indirectly against the adapted rim seat; a mounting/dismounting zone (70) arranged substantially adjacent to the bead seat, radially inside relative to the support zone, so as to facilitate mounting/dismounting of the tyre on the associated rim.

Description

PNEUMATIQUE AVEC BOURRELET MUNI D'UNE ZONE FAVORISANT LE TIRE WITH BUCKLE PROVIDED WITH A PROMOTING AREA
MONTAGE/DEMONTAGEASSEMBLY / DISASSEMBLY
La présente invention concerne un pneumatique pour roue de véhicule dans lequel au moins un des bourrelets comporte un siège avec une génératrice dont l'extrémité axialement intérieure est sur un cercle de diamètre supérieur au diamètre du cercle sur lequel se trouve l'extrémité axialement extérieure. Ce type de conception est particulièrement adapté aux nouvelles générations de pneumatiques pouvant être utilisés, dans certaines limites, dans des conditions de faible pression, voire de pression nulle ou quasi-nulle, avec une élimination du risque de désolidarisation du pneu de la jante sur laquelle il est monté. Ce concept est souvent désigné par l'expression "mobilité étendue".The present invention relates to a tire for a vehicle wheel in which at least one of the beads has a seat with a generator whose axially inner end is on a circle with a diameter greater than the diameter of the circle on which the axially outer end is located. This type of design is particularly suitable for new generations of tires which can be used, within certain limits, in conditions of low pressure, or even zero or almost zero pressure, with an elimination of the risk of the tire becoming detached from the rim on which it is mounted. This concept is often referred to as "extended mobility".
Depuis longtemps les fabricants de pneumatiques tentent de mettre au point un pneumatique ne créant aucune source de risque ou de danger potentiel lors d'un abaissement anormal, voire d'une perte totale de pression. Une des difficultés rencontrées concerne le roulage à plat ou à très faible pression. En effet, lors d'un roulage à très faible pression, voire à pression nulle avec des pneumatiques classiques, les bourrelets risquent fortement de se désolidariser du pourtour de la jante contre lequel ils étaient maintenus par la pression.For a long time, tire manufacturers have been trying to develop a tire that does not create any source of risk or potential danger during an abnormal lowering or even a total loss of pressure. One of the difficulties encountered relates to running flat or at very low pressure. In fact, when running at very low pressure, or even at zero pressure with conventional tires, the beads are very likely to become detached from the periphery of the rim against which they were held by the pressure.
De nombreuses solutions ont été testées afin de pallier ces inconvénients. Souvent ces solutions engendrent des difficultés supplémentaires au niveau du montage et du démontage du pneu sur la jante.Many solutions have been tested in order to overcome these drawbacks. Often these solutions cause additional difficulties in mounting and dismounting the tire on the rim.
Par ailleurs, la fonction serrage du pneumatique sur la jante est une fonction essentielle pour assurer les qualités du pneumatique en fonctionnement. En effet, elle agit directement ou indirectement sur de multiples aspects tels le montage (parfois désigné « clipsage ») ou fixation du pneumatique, l'étanchéité du pneumatique, la rotation sur jante, etc. Ces fonctions sont toutes critiques et nécessitent des caractéristiques spécifiques et une fabrication rigoureuse des produits, en particulier si des standards de qualité élevés sont recherchés. Hors, les jantes et les pneumatiques ont souvent, pour un même code, des dimensions légèrement différentes, principalement dues aux tolérances de fabrication. Ces variations de dimensions compliquent le respect des différentes fonctions préalablement énumérées.Furthermore, the function of tightening the tire on the rim is an essential function for ensuring the qualities of the tire in operation. Indeed, it acts directly or indirectly on multiple aspects such as mounting (sometimes called "clipping") or fixing the tire, sealing the tire, rotation on the rim, etc. These functions are all critical and require specific characteristics and rigorous manufacturing of the products, in particular if high quality standards are sought. out, rims and tires often have slightly different dimensions for the same code, mainly due to manufacturing tolerances. These dimensional variations complicate compliance with the various functions previously listed.
Pour remplir ces fonctions, on utilise industriellement deux grands types de solutions. Tout d'abord, pour les pneumatiques traditionnels, la tringle assure simultanément toutes ces fonctions.To fulfill these functions, two main types of solutions are used industrially. First of all, for traditional tires, the bead wire performs all of these functions simultaneously.
Plus récemment, pour plusieurs types de produits manufacturés par la demanderesse, la tringle classique est remplacée par une zone d'ancrage comportant notamment des arrangements de fils circonférentiels coopérant avec la structure de renfort de type carcasse via un mélange d'ancrage ou de liaison. Là encore, la zone d'ancrage assure toutes les fonctions présentées ci-dessus.More recently, for several types of products manufactured by the applicant, the conventional rod is replaced by an anchoring zone comprising in particular arrangements of circumferential wires cooperating with the carcass-type reinforcement structure via an anchoring or binding mixture. Again, the anchoring area provides all of the functions presented above.
Dans ces deux cas, il est toutefois difficile d'optimiser certains paramètres, car très souvent, l'amélioration de l'un, se fait au détriment d'un autre. Ce jeu de compromis entre gain d'un côté et pénalisation d'un autre, comporte donc certaines limites, puisqu'il est souvent difficile de tolérer de moins bonnes performances pour certains aspects.In these two cases, it is however difficult to optimize certain parameters, because very often, the improvement of one, is done to the detriment of another. This game of compromise between gain on one side and penalization on the other, therefore has certain limits, since it is often difficult to tolerate poorer performance for certain aspects.
Le document EP 0 582 196 présente un pneumatique comportant une bande de roulement prolongée par deux flancs et deux bourrelets ainsi qu'une carcasse ancrée dans les deux bourrelets à un renforcement annulaire. La carcasse est constituée de fils disposés de façon adjacente, alignés circonférentiellement et en contact avec au moins une couche de gomme de liaison de très haut module d'élasticité dans la zone d'accrochage du bourrelet comprenant le renforcement annulaire. Dans ce pneumatique, le renforcement annulaire de la zone d'accrochage du bourrelet est constitué de piles de fils circonférentiels avec interposition entre les fils de renforcement de la carcasse et ces piles d'une couche de gomme de liaison de très haut module d'élasticité. Ce mode de réalisation est destiné aux pneumatiques de type classique, avec maintien des bourrelets contre le crochet de jante dû à la pression de gonflage du pneumatique. On retrouve dans ce type d'agencement une prédominance d'efforts de type latéral ou axial, induisant d'importantes forces de compression agissant sensiblement axialement depuis les parois vers le centre dudit bourrelet. Ces forces augmentent en fonction de la pression de gonflage. L'augmentation de la pression tend à faire glisser le bourrelet contre le crochet, radialement vers l'extérieur. Les efforts induits radialement vers l'intérieur, contre le siège de la jante , diminuent avec l'augmentation de la pression, ou avec toute augmentation de la tension de la structure de renfort de type carcasse.Document EP 0 582 196 presents a tire comprising a tread extended by two sidewalls and two beads as well as a carcass anchored in the two beads with an annular reinforcement. The carcass is made up of threads placed adjacent to each other, circumferentially aligned and in contact with at least one layer of bonding rubber of very high elastic modulus in the attachment zone of the bead comprising the annular reinforcement. In this tire, the annular reinforcement of the bead attachment zone consists of stacks of circumferential cords with interposition between the reinforcing cords of the carcass and these stacks of a layer of bonding rubber of very high elasticity modulus . This embodiment is intended for tires of the conventional type, with retention of the beads against the rim hook due to the inflation pressure of the tire. pneumatic. We find in this type of arrangement a predominance of lateral or axial type forces, inducing significant compressive forces acting substantially axially from the walls towards the center of said bead. These forces increase as a function of the inflation pressure. The increase in pressure tends to slide the bead against the hook, radially outward. The forces induced radially inwards against the seat of the rim decrease with increasing pressure, or with any increase in tension in the carcass-type reinforcing structure.
On remarque par ailleurs que les piles de fils sont alignées dans un sens sensiblement parallèle à l'orientation du profil du crochet de jante contre lequel le bourrelet s'appuie. Le profil du bourrelet de ce type de pneumatique est relativement étroit et allongé; l'ancrage est réparti sur l'essentiel de la hauteur et de la largeur du bourrelet. Le passage de la carcasse dans le bourrelet est généralement sensiblement central par rapport aux parois dudit bourrelet. Par ailleurs, s'agissant d'un bourrelet relativement étroit sujet à des efforts à prédominance axiale, ni la pression de gonflage, ni la tension induite dans la carcasse ne permettent la génération d'important moments ou couples, tendant à faire pivoter ou tourner le bourrelet sur lui-même.Note also that the stacks of son are aligned in a direction substantially parallel to the orientation of the profile of the rim hook against which the bead is supported. The profile of the bead of this type of tire is relatively narrow and elongated; the anchor is distributed over most of the height and width of the bead. The passage of the carcass in the bead is generally substantially central with respect to the walls of said bead. Furthermore, in the case of a relatively narrow bead subject to predominantly axial forces, neither the inflation pressure nor the tension induced in the carcass allow the generation of significant moments or couples, tending to rotate or rotate the bead on itself.
Avec un tel type de pneumatique, si la pression chute et que le roulage se poursuit, le maintien du pneumatique sur la jante n'est plus assuré, et dans la plupart des cas, il se produit un déjantage.With such a type of tire, if the pressure drops and rolling continues, the maintenance of the tire on the rim is no longer ensured, and in most cases, there is a backlash.
Le document EP 0 673 324 décrit un ensemble roulant comprenant au moins un pneumatique à armature de carcasse radiale ancrée dans chaque bourrelet et une jante de conformation particulière. Cette jante comporte un premier siège avec une génératrice telle que l'extrémité axialement extérieure de ladite génératrice est distante de l'axe de rotation d'une longueur inférieure à la distance séparant son extrémité axialement intérieure et est délimitée axialement à l'extérieur par une saillie ou rebord de jante. Le pneumatique comporte des sièges de bourrelets adaptés pour un montage sur cette jante. Le type d'interface pneumatique/jante proposé dans ce document présente de nombreux avantages par rapport aux solutions déjà connues, notamment au niveau de la facilité de montage/démontage tout en permettant d'effectuer un certain parcours malgré une chute de pression.Document EP 0 673 324 describes a rolling assembly comprising at least one tire with a radial carcass reinforcement anchored in each bead and a rim of particular shape. This rim has a first seat with a generator such that the axially outer end of said generator is distant from the axis of rotation by a length less than the distance separating its axially inner end and is delimited axially on the outside by a rim protrusion or rim. The tire includes bead seats suitable for mounting on this rim. The type of pneumatic / rim interface proposed in this document has many advantages compared to already known solutions, in particular in terms of ease of assembly / disassembly while allowing a certain distance to be made despite a pressure drop.
Le document EP 0 748 287 décrit une solution permettant une première optimisation de la technologie de base décrite dans le document EP 0 673 324 préalablement cité. Il s'agit d'un pneumatique dont au moins un bourrelet a une structure permettant de modifier le serrage dudit bourrelet en fonction de la tension de l'armature de carcasse et notamment un renforcement de celui-ci lorsque la pression de gonflage s'accroît jusqu'à sa valeur nominale. Le document propose ainsi l'utilisation d'un bourrelet avec ancrage de l'extrémité de la carcasse par retournement de celle-ci autour de la base de la tringle, par les cotés axialement et radialement intérieurs par rapport à la tringle. Le bourrelet comporte également, adjacent à la tringle et axialement à l'extérieur de celle-ci, un profilé de mélange caoutchouteux de dureté relativement élevée contre lequel la tringle peut venir exercer une force de compression lors d'un accroissement de tension de l'armature de carcasse. Cette force de compression crée un auto-serrage de la pointe du bourrelet sur la jante de montage. La tension de la carcasse entraîne donc un déplacement de la tringle vers l'extérieur, afin que cette dernière génère ladite force de compression. Dans une telle configuration, la présence d'une tringle de type classique et le retournement de la carcasse sous cette dernière sont présentés comme étant indispensables pour générer la force de compression. Ceci limite les possibilités d'envisager d'autres types d'agencement.The document EP 0 748 287 describes a solution allowing a first optimization of the basic technology described in the document EP 0 673 324 previously cited. It is a tire of which at least one bead has a structure making it possible to modify the tightening of said bead as a function of the tension of the carcass reinforcement and in particular a reinforcement thereof when the inflation pressure increases. up to its nominal value. The document thus proposes the use of a bead with anchoring of the end of the carcass by turning it around the base of the rod, by the axially and radially inner sides with respect to the rod. The bead also comprises, adjacent to the rod and axially outside of the latter, a rubber mixture profile of relatively high hardness against which the rod can come to exert a compressive force during an increase in tension of the carcass reinforcement. This compressive force creates a self-tightening of the tip of the bead on the mounting rim. The tension of the carcass therefore causes the rod to move outward, so that the latter generates said compressive force. In such a configuration, the presence of a rod of the conventional type and the inversion of the carcass under the latter are presented as being essential for generating the compressive force. This limits the possibilities of considering other types of arrangement.
D'autre part, le document EP 0 922 592, décrit deux modes de réalisations avec ancrage de la carcasse par retournement de celle-ci axialement vers l'extérieur. Le premier mode propose un ancrage de la carcasse dans le bourrelet par retournement radialement vers l'extérieur de l'extrémité de la carcasse. Le retournement est entouré de part et d'autre par deux couches radialement superposées de fils métalliques disposés axialement côte à côte et couvrant sensiblement toute la portion axiale le long du siège du bourrelet. Les couches sont agencées de façon à être parallèles au siège. Les types de fils ainsi que les dimensions correspondantes sont très précises. La seconde solution proposée dans ce document concerne des sièges de bourrelets avec des diamètres différents. L'arrimage de la carcasse s'effectue également de façon différente par rapport à la première solution. Tout d'abord, la carcasse se subdivise en deux portions radialement séparées au niveau du bourrelet. Chaque portion est adjointe d'une couche de fils disposée radialement, chaque couche étant disposée radialement extérieurement contre chacune des portions de carcasse. La portion de carcasse radialement extérieure et la couche de fils radialement à l'intérieur sont séparées par un insert de type éiastomère à dureté élevée prévu dans le bourrelet. Cet insert garnit axialement la portion centrale du bourrelet et remonte radialement vers l'extérieur et axialement vers l'intérieur, au-delà de la limite radiale de présence des fils métalliques.On the other hand, document EP 0 922 592 describes two embodiments with anchoring of the carcass by turning it axially outwards. The first mode proposes an anchoring of the carcass in the bead by turning radially outward from the end of the carcass. The upturn is surrounded on either side by two radially superposed layers of metal wires arranged axially side by side and covering substantially the entire axial portion along the seat of the bead. The layers are arranged so as to be parallel to the seat. The types of wires and the corresponding dimensions are very precise. The second proposed solution in this document relates to bead seats with different diameters. The carcass is also stowed differently than the first solution. First of all, the carcass is subdivided into two radially separated portions at the level of the bead. Each portion is joined by a layer of wires arranged radially, each layer being disposed radially outwardly against each of the carcass portions. The radially outer carcass portion and the layer of wires radially inside are separated by an elastomer type insert of high hardness provided in the bead. This insert axially lines the central portion of the bead and rises radially outwards and axially inwards, beyond the radial limit of presence of the metallic wires.
Les deux exemples de solutions du document EP 0 922 592 comportent plusieurs inconvénients. Ainsi, l'arrimage de la carcasse proposé dans ce document nécessite la présence d'un retournement axialement vers l'extérieur de la portion d'extrémité de la carcasse. D'autre part, les couches de fils superposées sont disposées radialement près du siège du bourrelet, en bonne partie à une position radiale plus près de l'axe de rotation que la portion haute du rebord sur lequel le bourrelet appuie. A moins d'utiliser des fils fortement extensibles, le montage/démontage du pneumatique est difficile à exécuter, dû à la position radiale défavorable des fils. On remarque également que les piles sont orientées de façon sensiblement parallèle au profil du siège contre lequel le bourrelet appuie. Selon la seconde solution, la carcasse se subdivise en deux portions et un insert à dureté élevé est nécessaire pour séparer d'une part les couches de fils et d'autre part les deux portions de carcasse. L'ancrage de la carcasse n'est cependant pas réalisé dans l'insert. La forme de l'insert décrit est limitative.The two examples of solutions in document EP 0 922 592 have several drawbacks. Thus, the stowage of the carcass proposed in this document requires the presence of an axially outward turning of the end portion of the carcass. On the other hand, the superimposed layers of son are arranged radially near the seat of the bead, for the most part in a radial position closer to the axis of rotation than the upper portion of the rim on which the bead rests. Unless highly extensible cords are used, mounting / dismounting of the tire is difficult to perform, due to the unfavorable radial position of the cords. We also note that the stacks are oriented substantially parallel to the profile of the seat against which the bead presses. According to the second solution, the carcass is subdivided into two portions and a high hardness insert is necessary to separate on the one hand the layers of wires and on the other hand the two carcass portions. However, the carcass is not anchored in the insert. The shape of the insert described is limiting.
La présente invention propose donc de pallier les différents inconvénients inhérents aux solutions exposées ci-dessus.The present invention therefore proposes to overcome the various drawbacks inherent in the solutions set out above.
Pour ce faire, elle prévoit un pneumatique pour roue de véhicule, comprenant:To do this, it provides a tire for a vehicle wheel, comprising:
-deux flancs espacés axialement l'un de l'autre, réunis à leurs portions radialement extérieures par une zone de sommet pourvue sur sa portion radialement extérieure d'une bande de roulement circonférentielle ;-two sides spaced axially from each other, joined to their portions radially exterior by a crown zone provided on its radially exterior portion with a circumferential tread;
-des bourrelets, disposés radialement intérieurement à chacun des flancs, chaque bourrelet comportant un siège et un rebord externe destinés à venir en contact avec une jante adaptée ;-beads, arranged radially inside each of the sidewalls, each bead comprising a seat and an external flange intended to come into contact with a suitable rim;
-une structure de renfort s'étendant sensiblement radialement depuis chacun des bourrelets, le long des flancs, vers la zone sommet ;a reinforcing structure extending substantially radially from each of the beads, along the flanks, towards the crown area;
- au moins un desdits bourrelets comprenant :- at least one of said beads comprising:
- un siège de bourrelet comportant une génératrice dont l'extrémité axialement intérieure est sur un cercle de diamètre supérieur au diamètre du cercle sur lequel se trouve l'extrémité axialement extérieure ;- a bead seat comprising a generator whose axially inner end is on a circle of diameter greater than the diameter of the circle on which the axially outer end is located;
- une zone d'ancrage de la structure de renfort dans ledit bourrelet, comprenant un arrangement sensiblement radial de fils circonférentiels disposé de façon sensiblement adjacente à une portion de la structure de renfort et comprenant au moins deux piles réparties de part et d'autre de la structure de renfort, un mélange de liaison étant disposé entre les fils circonférentiels et la structure de renfort ;a zone for anchoring the reinforcement structure in said bead, comprising a substantially radial arrangement of circumferential wires disposed substantially adjacent to a portion of the reinforcement structure and comprising at least two stacks distributed on either side of the reinforcement structure, a connection mixture being arranged between the circumferential wires and the reinforcement structure;
- une zone de « montage/démontage » disposée sensiblement adjacente au siège du bourrelet, radialement intérieurement à la zone d'ancrage, et dont la distance correspond sensiblement à la distance BS-BC, où BS est la base du siège et BC est la base du crochet de jante.- an “assembly / disassembly” zone disposed substantially adjacent to the seat of the bead, radially inside the anchoring zone, and the distance of which corresponds substantially to the distance BS-BC, where BS is the base of the seat and BC is the rim hook base.
La présence de cette zone, correspondant sensiblement à la zone la plus sollicitée lors des opérations de montage/démontage, vise à faciliter ou optimiser le montage/démontage du pneumatique sur la jante associée. Cette zone est donc légèrement déformable, en particulier lors du montage ou du démontage, notamment lors du passage sur le crochet de jante. Elle est également endurante, pour subir les cycles répétés de montage/démontage, sans détérioration particulière.The presence of this zone, corresponding substantially to the zone most requested during mounting / dismounting operations, aims to facilitate or optimize the mounting / dismounting of the tire on the associated rim. This area is therefore slightly deformable, in particular during assembly or disassembly, in particular when passing over the rim hook. It is also enduring, to undergo repeated cycles of assembly / disassembly, without deterioration special.
Selon un mode de réalisation avantageux, le bourrelet comprend par ailleurs :According to an advantageous embodiment, the bead further comprises:
- une zone intermédiaire, disposée sensiblement axialement extérieurement à la zone d'ancrage et comportant au moins une portion sensiblement alignée radialement avec la zone d'ancrage ;- An intermediate zone, arranged substantially axially outside the anchoring zone and comprising at least one portion substantially aligned radially with the anchoring zone;
- une zone d'appui dudit bourrelet susceptible de reposer directement ou indirectement contre le siège de jante adapté, et comprenant au moins une portion axialement alignée avec la zone intermédiaire et radialement intérieure à cette zone ;- A support zone of said bead capable of resting directly or indirectly against the adapted rim seat, and comprising at least one portion axially aligned with the intermediate zone and radially internal to this zone;
- ladite zone de « montage/démontage » étant disposée sensiblement axialement intérieurement à la zone d'appui.- Said "mounting / dismounting" area being arranged substantially axially internally to the support area.
Une telle configuration permet un maintien optimal du bourrelet dans la jante, notamment au niveau de l'interface siège de la jante/siège du bourrelet. Les forces agissant sur la zone d'ancrage sont alors bien transmises vers la zone du siège du bourrelet. La continuité radiale permet de minimiser l'impact des forces , de cisaillement agissant contre le bourrelet dans son ensemble.Such a configuration allows optimal retention of the bead in the rim, in particular at the level of the rim seat / bead seat interface. The forces acting on the anchoring zone are then well transmitted to the zone of the seat of the bead. The radial continuity makes it possible to minimize the impact of the shearing forces acting against the bead as a whole.
Selon un exemple de réalisation avantageux de l'invention, la zone de montage/démontage forme un prolongement radialement intérieur à la zone d'ancrage.According to an advantageous embodiment of the invention, the assembly / disassembly zone forms an extension radially inside the anchoring zone.
Le matériau de la zone de montage-démontage comporte de préférence un module sensiblement inférieur à celui du matériau de la zone d'appui.The material of the assembly-disassembly zone preferably comprises a module substantially smaller than that of the material of the support zone.
La zone d'ancrage ne comporte pas de tringle, notamment de tringle de type traditionnel, comme par exemple une tringle multifilaire contre laquelle une nappe carcasse est retournée, de façon à ce que la zone.de coopération entre la portion retournée de nappe et la tringle procure le maintien de la nappe carcasse. Chacune des zones prises isolément de même que l'ensemble des zones forment en quelque sorte un bourrelet interne susceptible d'effectuer des mouvements relatifs, comme par exemple de type angulaire ou en rotation, par rapport à une autre zone, ou par rapport à un centre de pression CP virtuel, ou par rapport au siège de la jante, etc.The anchoring zone does not comprise a rod, in particular a rod of the traditional type, such as for example a multi-wire rod against which a carcass ply is turned over, so that the zone of cooperation between the inverted portion of ply and the rod provides support for the carcass ply. Each of the zones taken in isolation as well as all of the zones form a sort of internal bead capable of effecting relative movements, such as for example of angular or rotating type, with respect to another zone, or with respect to a virtual CP pressure center, or relative to the rim seat, etc.
De manière avantageuse, la zone intermédiaire, assure une connexion mécanique entre ladite zone d'ancrage et ladite zone d'appui. La zone intermédiaire assure une continuité entre les deux autres zones, de façon à ce que les efforts mécaniques soient transmis de la zone d'ancrage vers la zone d'appui.Advantageously, the intermediate zone provides a mechanical connection between said anchoring zone and said support zone. The intermediate zone provides continuity between the two other zones, so that the mechanical forces are transmitted from the anchoring zone to the support zone.
La zone intermédiaire est susceptible d'exercer un effort sensiblement radialement vers l'intérieur contre la portion axialement extérieure de la zone d'appui.The intermediate zone is likely to exert a force substantially radially inwards against the axially external portion of the support zone.
La zone intermédiaire, assure une connexion mécanique entre ladite zone d'ancrage et ladite zone d'appui. La zone d'ancrage et la zone intermédiaire peuvent être jumelées mécaniquement. Il en est de même pour la zone intermédiaire qui peut être jointe à la zone d'appui. Mais la zone d'ancrage est de préférence non directement jointe à la zone d'appui.The intermediate zone provides a mechanical connection between said anchoring zone and said support zone. The anchoring zone and the intermediate zone can be mechanically combined. It is the same for the intermediate zone which can be joined to the support zone. However, the anchoring zone is preferably not directly joined to the support zone.
De préférence, ladite zone d'appui est sensiblement allongée. Elle se prolonge par exemple sensiblement le long du siège du bourrelet. Le transfert des efforts lors de la rotation de la zone basse de la portion axialement interne vers la portion axialement externe est ainsi possible, tout en conservant un appui contre au moins une portion du siège du bourrelet. Le transfert des efforts assure un autoserrage de la pointe du bourrelet contre la jante.Preferably, said support zone is substantially elongated. It extends for example substantially along the seat of the bead. The transfer of forces during the rotation of the lower zone of the axially internal portion towards the axially external portion is thus possible, while retaining support against at least a portion of the seat of the bead. The transfer of forces ensures self-tightening of the tip of the bead against the rim.
De manière préférentielle, la zone d'appui est sensiblement constituée d'un mélange de gomme à haut module.Preferably, the support zone is substantially constituted by a mixture of high modulus rubber.
Selon un mode de fabrication particulièrement avantageux où les différents constituants du pneumatique sont disposés directement sur un noyau central dont la forme confère au pneumatique en cours de fabrication une forme sensiblement similaire à la forme du produit fini, la suppression du retournement (qui existe avec une architecture traditionnelle) permet une simplification avantageuse de la fabrication.According to a particularly advantageous manufacturing method where the various constituents of the tire are arranged directly on a central core, the shape gives the tire during manufacture a shape substantially similar to the shape of the finished product, the elimination of turning (which exists with a traditional architecture) allows an advantageous simplification of manufacturing.
Selon une forme d'exécution avantageuse de l'invention, les bases des piles (les fils radialement les plus près de l'axe de rotation du pneumatique) sont disposées radialement plus à l'extérieur que l'extrémité dudit rebord (portion axialement et radialement la plus à l'extérieur dudit rebord). Les bases des piles sont avantageusement prévues de façon à être disposées radialement extérieurement par rapport au rebord de la jante adaptée au pneumatique. Les opérations de montage/démontage sont alors facilitées.According to an advantageous embodiment of the invention, the bases of the piles (the wires radially closest to the axis of rotation of the tire) are arranged radially more outside than the end of said rim (portion axially and radially outermost of said edge). The bases of the stacks are advantageously provided so as to be arranged radially outwardly relative to the rim of the rim adapted to the tire. The assembly / disassembly operations are then facilitated.
De manière avantageuse, la structure de renfort de type carcasse s'étend sensiblement radialement depuis chacun des bourrelets, le long des flancs, vers la zone sommet. Ladite structure peut ainsi être unitaire et s'étendre d'un bourrelet à l'autre, ou encore être partagée en deux demi-structures, s'étendant chacune le long d'un seul flanc.Advantageously, the carcass-type reinforcement structure extends substantially radially from each of the beads, along the sides, towards the crown zone. Said structure can thus be unitary and extend from one bead to another, or even be divided into two half-structures, each extending along a single flank.
Le nombre de piles ainsi que le nombre d'enroulements ou de spires de chacune des piles est avantageusement établi en fonction des caractéristiques recherchées pour le pneumatique, par exemple sa pression de service. Par exemple, un nombre de piles plus élevé peut être souhaité afin d'augmenter la rigidité au niveau de la zone du bourrelet.The number of stacks as well as the number of windings or turns of each of the stacks is advantageously established as a function of the characteristics sought for the tire, for example its operating pressure. For example, a higher number of stacks may be desired in order to increase the rigidity at the bead area.
La structure de renfort de type carcasse est de préférence constituée d'un enroulement filaire faisant des aller-retours entre les deux, bourrelets en formant dans chacun des bourrelets des boucles. Par ailleurs, l'enroulement filaire est préférablement constitué d'un seul fil.The carcass-type reinforcement structure preferably consists of a wire winding going back and forth between the two, beads forming loops in each of the beads. Furthermore, the wire winding preferably consists of a single wire.
D'autres caractéristiques et avantages de l'invention apparaîtront à la lecture des exemples de réalisation du pneumatique conforme à l'invention, donnés à titre non limitatif et en se référant aux figures 1 à 3 annexées, dans lesquelles: la figure 1 illustre, en coupe transversale, un pneumatique selon l'invention;Other characteristics and advantages of the invention will appear on reading the exemplary embodiments of the tire according to the invention, given without limitation and with reference to the appended FIGS. 1 to 3, in which: FIG. 1 illustrates, in cross section, a tire according to the invention;
la figure 2 illustre, en coupe transversale agrandie, un bourrelet d'une première variante d'un pneumatique selon l'invention;FIG. 2 illustrates, in enlarged cross-section, a bead of a first variant of a tire according to the invention;
la figure 3 illustre, en coupe transversale agrandie, une autre variante de bourrelets, où les différentes zones du . bourrelet sont agencées de façon avantageuse.Figure 3 illustrates, in enlarged cross section, another variant of beads, where the different areas of . bead are arranged advantageously.
L'armature de renforcement ou renforcement des pneumatiques est à l'heure actuelle - et le plus souvent - constituée par empilage d'une ou plusieurs nappes désignées classiquement « nappes de carcasse », «nappes sommet », etc. Cette façon de désigner les armatures de renforcement provient du procédé de fabrication, consistant à réaliser une série de produits semi-finis en forme de nappes, pourvues de renforts filaires souvent longitudinaux, qui sont par la suite assemblées ou empilées afin de confectionner une ébauche de pneumatique. Les nappes sont réalisées à plat, avec des dimensions importantes, et sont par la suite coupées en fonction des dimensions d'un produit donné. L'assemblage des nappes est également réalisé, dans un premier temps, sensiblement à plat. L'ébauche ainsi réalisée est ensuite mise en forme pour adopter le profil toroïdal typique des pneumatiques. Les produits semi-finis dits « de finition » sont ensuite appliqués sur l'ébauche, pour obtenir un produit prêt pour la vulcanisation.The reinforcement or reinforcement of tires is currently - and most often - constituted by stacking one or more plies conventionally designated “carcass plies”, “crown plies”, etc. This way of designating the reinforcing reinforcements comes from the manufacturing process, consisting in producing a series of semi-finished products in the form of plies, provided with wire reinforcements often longitudinal, which are then assembled or stacked in order to make a blank of pneumatic. The sheets are made flat, with large dimensions, and are then cut according to the dimensions of a given product. The plies are also assembled, initially, substantially flat. The blank thus produced is then shaped to adopt the toroidal profile typical of tires. The semi-finished products called "finishing" are then applied to the blank, to obtain a product ready for vulcanization.
Un tel type de procédé "classique" implique, en particulier pour la phase de fabrication de l'ébauche du pneumatique, l'utilisation d'un élément d'ancrage (généralement une tringle), utilisée pour réaliser l'ancrage ou le maintien de l'armature de carcasse dans la zone des bourrelets du pneumatique. Ainsi, pour ce type de procédé, on effectue un retournement d'une portion de toutes les nappes composant l'armature de carcasse (ou d'une partie seulement) autour d'une tringle disposée dans le bourrelet du pneumatique. On crée de la sorte un ancrage de l'armature de carcasse dans le bourrelet. La généralisation dans l'industrie de ce type de procédé classique, malgré de nombreuses variantes dans la façon de réaliser les nappes et les assemblages, a conduit l'homme du métier à utiliser un vocabulaire calqué sur le procédé ; d'où la terminologie généralement admise, comportant notamment les termes «nappes», 5 «carcasse», «tringle», «conformation» pour désigner le passage d'un profil plat à un profil toroïdal, etc.Such a “conventional” method involves, in particular for the manufacturing phase of the tire blank, the use of an anchoring element (generally a bead wire), used to anchor or maintain the carcass reinforcement in the area of the tire beads. Thus, for this type of process, a portion of all the plies making up the carcass reinforcement (or a portion only) is turned around a bead wire disposed in the bead of the tire. This creates an anchoring of the carcass reinforcement in the bead. The generalization in the industry of this type of conventional process, in spite of numerous variants in the way of making the sheets and the assemblies, led the person skilled in the art to use a vocabulary modeled on the process; hence the generally accepted terminology, including in particular the terms "plies", 5 "carcass", "rod", "conformation" to designate the transition from a flat profile to a toroidal profile, etc.
Cependant, il existe aujourd'hui des pneumatiques qui ne comportent à proprement parler pas de «nappes» ou de «tringles» d'après les définitions précédentes. Par exemple, le document EP 0 582 196 décrit des pneumatiques . ι.o fabriqués sans l'aide de produits semi-finis sous forme de nappes. Par exemple, les fils des différentes structures de renfort sont appliqués directement sur les couches adjacentes de mélanges caoutchoutiques, le tout étant appliqué par couches successives sur un noyau toroïdal dont la forme permet d'obtenir directement un profil s'apparentant au profil final du pneumatique en cours deHowever, today there are tires which do not, strictly speaking, have “plies” or “bead wires” according to the preceding definitions. For example, document EP 0 582 196 describes tires. ι.o manufactured without the help of semi-finished products in the form of tablecloths. For example, the threads of the various reinforcing structures are applied directly to the adjacent layers of rubber mixtures, the whole being applied in successive layers to a toroidal core whose shape makes it possible to directly obtain a profile similar to the final profile of the tire. being
15 fabrication. Ainsi, dans ce cas, on ne retrouve plus de «semi-finis», ni de «nappes», ni de «tringle». Les produits de base tels les mélanges caoutchoutiques et les renforts sous forme de fils ou filaments, sont directement appliqués sur le noyau. Ce noyau étant de forme toroïdale, on n'a plus à former l'ébauche pour passer d'un profil plat à un profil sous forme de tore.15 manufacturing. Thus, in this case, there are no more "semi-finished", nor "tablecloths", nor "rod". The basic products such as rubber mixes and reinforcements in the form of threads or filaments are applied directly to the core. This core being of toroidal shape, we no longer have to form the blank to pass from a flat profile to a profile in the form of a torus.
0 Par ailleurs, les pneumatiques décrits dans ce document ne disposent pas du "traditionnel" retournement de nappe carcasse autour d'une tringle. Ce type d'ancrage est remplacé par un agencement dans lequel on dispose de façon adjacente à ladite structure de renfort de flanc des filaments circonférentiels, le tout étant noyé dans un mélange caoutchoutique d'ancrage ou de liaison.0 Furthermore, the tires described in this document do not have the "traditional" turning of the carcass ply around a bead wire. This type of anchoring is replaced by an arrangement in which there is disposed adjacent to said flank reinforcement structure of the circumferential filaments, the whole being embedded in a rubber mixture of anchoring or binding.
5 II existe également des procédés d'assemblage sur noyau toroïdal utilisant des produits semi-finis spécialement adaptés pour une pose rapide, efficace et simple sur un noyau central. Enfin, il est également possible d'utiliser un mixte comportant à la fois certains produits semi-finis pour réaliser certains aspects architecturaux (tels que des nappes, tringles, etc), tandis que d'autres sont réalisés à partir de l'application directe de mélanges et/ou de renforts sous forme de filaments.There are also methods of assembly on a toroidal core using semi-finished products specially adapted for rapid, efficient and simple installation on a central core. Finally, it is also possible to use a composite comprising both certain semi-finished products to achieve certain architectural aspects (such as tablecloths, rods, etc.), while others are made from the direct application of mixtures and / or reinforcements in the form of filaments.
Dans le présent document, afin de tenir compte des évolutions technologiques récentes tant dans le domaine de la fabrication que pour la conception de produits, les termes classiques tels que «nappes», «tringles», etc, sont avantageusement remplacés par des termes neutres ou indépendants du type de procédé utilisé. Ainsi, le terme «renfort de type carcasse» ou «renfort de flanc» est valable pour désigner les fils de renforts d'une nappe carcasse dans le procédé classique, et les fils correspondants, en général appliqués au niveau des flancs, d'un pneumatique produit selon un procédé sans semi-finis. Le terme «zone d'ancrage» pour sa part, peut désigner tout autant le "traditionnel" retournement de nappe carcasse autour d'une tringle d'un procédé classique, que l'ensemble formé par les filaments circonférentiels, le mélange caoutchoutique et les portions adjacentes de renfort de flanc d'une zone basse réalisée avec un procédé avec application sur un noyau toroïdal.In this document, in order to take account of recent technological developments both in the field of manufacturing and for the design of products, the conventional terms such as "tablecloths", "rods", etc., are advantageously replaced by neutral terms or independent of the type of process used. Thus, the term “carcass-type reinforcement” or “sidewall reinforcement” is valid for designating the reinforcing threads of a carcass ply in the conventional process, and the corresponding threads, generally applied at the flanks, of a tire produced using a semi-finished process. The term “anchoring zone” for its part, can designate the “traditional” turning of the carcass ply around a rod of a conventional process just as much as the assembly formed by the circumferential filaments, the rubber mixture and the adjacent flank reinforcement portions of a lower zone produced with a method with application to a toroidal core.
Dans la présente description, le terme "fil" désigne en toute généralité aussi bien des monofilaments que des multifilaments ou des assemblages comme des câbles, des retors ou encore tout type d'assemblage équivalent, et ceci, quels que soient la matière et le traitement de ces fils. Il peut s'agir par exemple de traitements de surface, enrobage ou pré-encollage pour favoriser l'adhérence sur le caoutchouc. L'expression « fil unitaire » désigne un fil composé d'un seul élément, sans assemblage. Le terme « multifilaments » désigne au contraire un assemblage d'au moins deux éléments unitaires pour former un câble, un retors, etc.In the present description, the term "thread" generally designates both monofilaments and multifilaments or assemblies such as cables, twists or any other equivalent type of assembly, regardless of the material and the treatment. of these sons. It may for example be surface treatments, coating or pre-sizing to promote adhesion to the rubber. The expression “unitary wire” designates a wire composed of a single element, without assembly. The term “multifilaments” on the contrary designates an assembly of at least two unitary elements to form a cable, a twist, etc.
D'autre part, on entend par structure radiale, un agencement à 90 degrés, mais aussi, selon l'usage, à un angle proche de 90°.On the other hand, by radial structure is meant an arrangement at 90 degrees, but also, depending on usage, at an angle close to 90 °.
On sait que, de façon traditionnelle, la ou les nappes de carcasse sont retournées autour d'une tringle. La tringle remplit alors une fonction d'ancrage de la carcasse. Ainsi, notamment, elle supporte la tension se développant dans les fils de carcasse par exemple sous l'effet de la pression de gonflage. L'agencement décrit dans le présent document permet d'assurer une fonction similaire d'ancrage. Il est également connu d'utiliser la tringle de type traditionnel pour assurer une fonction de serrage du bourrelet sur une jante. L'agencement décrit dans le présent document permet également d'assurer un rôle similaire de serrage.We know that, in a traditional way, the carcass ply (s) are turned around around a rod. The rod then fulfills a function of anchoring the carcass. Thus, in particular, it supports the tension developing in the wires of carcass for example under the effect of inflation pressure. The arrangement described in this document ensures a similar anchoring function. It is also known to use the rod of the traditional type to ensure a function of tightening the bead on a rim. The arrangement described in this document also ensures a similar tightening role.
Dans la présente description, on entend par gomme ou mélange de « liaison », le mélange caoutchoutique éventuellement en contact avec les fils de renforcement, adhérant à ceux-ci et susceptible de remplir les interstices entre fils adjacents.In the present description, the term "gum" or "bonding" mixture is understood to mean the rubber mixture possibly in contact with the reinforcing wires, adhering to them and capable of filling the interstices between adjacent wires.
On entend par "contact" entre un fil et une couche de gomme de liaison le fait qu'au moins une partie de la circonférence extérieure du fil est en contact intime avec le mélange caoutchoutique constituant de la gomme de liaison.The term "contact" between a wire and a layer of bonding rubber means that at least part of the outer circumference of the wire is in intimate contact with the rubber mixture constituting the bonding rubber.
On désigne "flancs" les portions du pneumatique le plus souvent de faible rigidité de flexion situées entre le sommet et les bourrelets. On appelle "mélange flancs" les mélanges caoutchoutiques situés axialement extérieurement relativement aux fils de la structure de renforcement de la carcasse et à leur gomme de liaison. Ces mélanges ont habituellement un bas module d'élasticité.The sidewalls are the portions of the tire most often of low bending stiffness located between the crown and the beads. “Sidewall mixes” are rubber mixes located axially outwardly relative to the wires of the carcass reinforcement structure and to their bonding rubber. These mixtures usually have a low modulus of elasticity.
On appelle "bourrelet" la portion du pneumatique adjacente radialement intérieurement au flanc.The portion of the tire adjacent radially inside the sidewall is called "bead".
On entend par "module d'élasticité" d'un mélange caoutchoutique, un module d'extension sécant obtenu à une déformation d'extension uniaxiale de l'ordre de 10% à température ambiante.The term “modulus of elasticity” of a rubber mixture is understood to mean a secant extension module obtained at a uniaxial extension deformation of the order of 10% at ambient temperature.
La figure 1 illustre, en coupe transversale, un pneumatique 1 selon l'invention. Ce pneumatique comprend un premier flanc 5 adjacent à un premier bourrelet 3 correspondant de préférence au bourrelet intérieur. De façon similaire, la portion opposée du pneumatique comprend un second flanc 6 adjacent à un second bourrelet 4. Un sommet 7, sur lequel est prévue une bande de roulement 8, assure la jonction entre les flancs. Le sommet comporte de préférence au moins une ceinture de renfort. Le pneumatique comporte une structure de renfort de type carcasse 2, pourvue de renforts avantageusement configurés selon un agencement sensiblement radial. Cette structure peut être agencée de façon continue d'un bourrelet à l'autre, en passant par les flancs et le sommet, ou encore, elle peut comporter deux ou plusieurs parties, agencées par exemple le long des flancs, sans couvrir la totalité du sommet.FIG. 1 illustrates, in cross section, a tire 1 according to the invention. This tire comprises a first sidewall 5 adjacent to a first bead 3 preferably corresponding to the inner bead. Similarly, the opposite portion of the tire comprises a second sidewall 6 adjacent to a second bead 4. A crown 7, on which a tread 8 is provided, provides the junction between the sidewalls. The top preferably includes at least one reinforcing belt. The tire comprises a carcass-type reinforcement structure 2, provided with reinforcements advantageously configured in a substantially radial arrangement. This structure can be arranged continuously from one bead to the other, passing through the sides and the top, or it can comprise two or more parts, arranged for example along the sides, without covering the entire Mountain peak.
Les portions d'extrémité de la structure de renfort 2 sont situées dans les bourrelets.The end portions of the reinforcing structure 2 are located in the beads.
La structure de renfort 2 peut être réalisée par enroulement d'un seul fil faisant des aller-retours entre les deux bourrelets en formant dans chacun des bourrelets des boucles. Ces boucles, enrobées dans le mélange caoutchoutique, contribuent à la liaison mécanique entre la structure de renfort 2 et le bourrelet, notamment les piles 13. Par la présence de boucles entre le parcours "aller" et le "retour" du fil, on voit que le renforcement est de type monofilament. Bien entendu, la carcasse pourrait ne pas être fabriquée de façon continue à partir d'un seul fil, et il pourrait ne pas y avoir de boucles, mais par exemple des extrémités coupées.The reinforcing structure 2 can be produced by winding a single wire going back and forth between the two beads, forming loops in each of the beads. These loops, coated in the rubber mixture, contribute to the mechanical connection between the reinforcement structure 2 and the bead, in particular the piles 13. By the presence of loops between the "outward" course and the "return" of the wire, we see that the reinforcement is of the monofilament type. Of course, the carcass might not be made continuously from a single wire, and there might not be loops, but for example cut ends.
Le bourrelet comporte par ailleurs une zone d'ancrage 30 comprenant un arrangement de fils circonférentiels disposés de façon sensiblement adjacente à une portion de la structure de renfort et comprend au moins deux piles réparties de part et d'autre de la structure de renfort, un mélange de liaison (ou d'ancrage) étant disposé entre les fils circonférentiels et la structure de renfort.The bead further comprises an anchoring zone 30 comprising an arrangement of circumferential wires disposed substantially adjacent to a portion of the reinforcement structure and comprises at least two stacks distributed on either side of the reinforcement structure, a bonding (or anchoring) mixture being disposed between the circumferential wires and the reinforcing structure.
Dans la zone d'ancrage, au moins un fil 12 d'une des piles 13 est de préférence disposé à proximité immédiate d'une portion 21 de la structure de renfort 2. Les piles peuvent également être agencées de façon à ce qu'une portion 21 soit intercalée entre des piles 13.In the anchoring zone, at least one wire 12 from one of the stacks 13 is preferably placed in the immediate vicinity of a portion 21 of the reinforcing structure 2. The stacks can also be arranged so that a portion 21 is interposed between batteries 13.
L'espace entre les fils 12 et la structure de renfort 2 est occupé par un mélange caoutchoutique de liaison14. On peut également prévoir l'utilisation de plusieurs mélanges ayant des caractéristiques différentes, délimitant plusieurs zones, les combinaisons de mélanges et les agencements résultants étant quasi-illimités. Selon une variante avantageuse, on prévoit la présence d'un mélange de gomme à sensiblement haut module d'élasticité dans la zone d'intersection entre l'arrangement de fils 11 et la structure de renfort 2. A titre d'exemple non limitatif, le module d'élasticité d'une telle. gomme peut atteindre 10 à 20 et même dépasser 40 Mpa.The space between the wires 12 and the reinforcement structure 2 is occupied by a rubber bonding mixture14. It is also possible to provide for the use of several mixtures having different characteristics, delimiting several zones, the combinations of mixtures and the resulting layouts being almost unlimited. According to an advantageous variant, provision is made for the presence of a rubber mixture with a substantially high modulus of elasticity in the area of intersection between the arrangement of wires 11 and the reinforcement structure 2. By way of nonlimiting example, the modulus of elasticity of such . gum can reach 10 to 20 and even exceed 40 Mpa.
Les arrangements de fils 11 peuvent être agencés et fabriqués différemment. Par exemple, une pile 13 peut avantageusement être constituée d'un seul fil 12, enroulé (sensiblement à zéro degrés) en spirale, de préférence depuis le plus petit diamètre vers le plus grand diamètre. Une pile peut également être constituée de plusieurs fils concentriques posés l'un dans l'autre.The wire arrangements 11 can be arranged and manufactured differently. For example, a battery 13 can advantageously consist of a single wire 12, wound (substantially at zero degrees) in a spiral, preferably from the smallest diameter to the largest diameter. A pile can also consist of several concentric wires laid one inside the other.
De façon surprenante, il a été constaté que l'ancrage de la structure de renfort dans le bourrelet peut être réalisé par le type d'interface décrite, malgré le fait que dans le pneumatique à mobilité étendue selon l'invention, les forces induites au niveau du bourrelet diffèrent de celles d'un bourrelet de type classique. Par exemple, avec le pneumatique selon l'invention, une augmentation de pression occasionne une augmentation de la poussée radiale de la portion radialement extérieure du siège du bourrelet contre le siège de la jante.Surprisingly, it has been found that the anchoring of the reinforcing structure in the bead can be achieved by the type of interface described, despite the fact that in the tire with extended mobility according to the invention, the forces induced at the level of the bead differ from those of a conventional bead. For example, with the tire according to the invention, an increase in pressure causes an increase in the radial thrust of the radially outer portion of the seat of the bead against the seat of the rim.
Les figures 2 et 3 illustrent différents exemples d'agencements des autres zones du bourrelet. Radialement intérieurement à la zone d'ancrage, ou plus particulièrement dans la portion radialement interne du bourrelet, dans la zone du siège, une zone d'appui 50 est prévue. Cette zone agit en tant qu'interface entre le reste du bourrelet et le siège de la jante. D'importants efforts de type radial. et axial sont donc transmis par cette zone. Un mélange caoutchouteux à haut module contribue au transfert de ces efforts en assurant un bon maintien du bourrelet contre la jante.Figures 2 and 3 illustrate different examples of arrangements of the other zones of the bead. Radially inside the anchoring zone, or more particularly in the radially internal portion of the bead, in the seat zone, a support zone 50 is provided. This area acts as an interface between the rest of the bead and the seat of the rim. Significant efforts of the radial type. and axial are therefore transmitted by this zone. A high modulus rubber mixture contributes to the transfer of these forces by ensuring good retention of the bead against the rim.
Entre ces deux premières zones, une zone intermédiaire 40 est avantageusement prévue, de façon à assurer une continuité mécanique. Les efforts peuvent ainsi être transmis de la zone d'ancrage 30 vers la zone d'appui 50, via la zone intermédiaire 40.Between these first two zones, an intermediate zone 40 is advantageously provided, so as to ensure mechanical continuity. The forces can thus be transmitted from the anchoring zone 30 to the support zone 50, via the zone intermediate 40.
Les trois zones peuvent également être jointes, pour former un ensemble unifié tel qu'illustré par exemple à la figure 2.The three zones can also be joined, to form a unified whole as illustrated for example in FIG. 2.
Une zone de « montage/démontage » 70 est disposée sensiblement adjacente au siège du bourrelet, radialement intérieurement à la zone d'ancrage. Elle s'étend sensiblement radialement depuis entre les points ou cotes BS-BC, où BS est la base du siège et BC est la base du crochet de jante. La zone 70 a donc en quelque sorte une « hauteur » correspondant sensiblement à la distance entre BS et BC.An “assembly / disassembly” zone 70 is arranged substantially adjacent to the seat of the bead, radially inside the anchoring zone. It extends substantially radially from between the points or dimensions BS-BC, where BS is the base of the seat and BC is the base of the rim hook. The area 70 therefore has a sort of "height" corresponding substantially to the distance between BS and BC.
La présence de cette zone vise à faciliter/optimiser le montage/démontage du pneumatique sur la jante associée, notamment en conférant une certaine souplesse à l'une des zones les plus sollicitées lors des opérations de montage ou démontage du pneumatique.The presence of this zone aims at facilitating / optimizing the mounting / dismounting of the tire on the associated rim, in particular by conferring a certain flexibility on one of the areas most requested during mounting or dismounting operations of the tire.
Tel qu'illustré dans les exemples de réalisations des figures 2 et 3, la zone de « montage/démontage » est disposée sensiblement axialement intérieurement à la zone d'appui.As illustrated in the exemplary embodiments of FIGS. 2 and 3, the “assembly / disassembly” zone is arranged substantially axially internally to the support zone.
Dans l'exemple de la figure 3, la zone de montage/démontage forme un prolongement radialement intérieur à la zone d'ancrage.In the example of FIG. 3, the assembly / disassembly zone forms an extension radially inside the anchoring zone.
Il est également à noter que le matériau de la zone de montage-démontage comporte de préférence un module sensiblement inférieur à celui du matériau de la zone d'appui.It should also be noted that the material of the assembly-disassembly zone preferably comprises a module substantially smaller than that of the material of the support zone.
Le pneumatique selon l'invention est particulièrement adapté pour être utilisé sur une jante du type de celle décrite dans le document EP 0 673 324. Une telle jante comporte un siège et de préférence un rehaussement ou rebord situé axialement et radialement vers l'extérieur. La qualité du contact ou de l'appui du bourrelet sur le siège est particulièrement importante. Un des moyens selon l'invention utilisés pour l'améliorer consiste à optimiser le phénomène préalablement décrit de rotation de la zone basse du bourrelet.The tire according to the invention is particularly suitable for use on a rim of the type described in document EP 0 673 324. Such a rim comprises a seat and preferably a raising or rim located axially and radially outward. The quality of contact or support of the bead on the seat is particularly important. One of the means according to the invention used to improve it consists in optimizing the previously described phenomenon of rotation of the lower zone of the bead.
Ce phénomène découle de la structure du bourrelet utilisé. La position axiale de la structure de renfort 2 par rapport au centre de poussée CP du bourrelet peut, dans une certaine mesure, influencer le moment M créé par une force de tension T induite dans la structure de renfort. Ce moment M agit sur l'effet de rotation de la zone basse du bourrelet.This phenomenon stems from the structure of the bead used. The axial position of the reinforcement structure 2 relative to the center of thrust CP of the bead can, to a certain extent, influence the moment M created by a tension force T induced in the reinforcement structure. This moment M acts on the effect of rotation of the lower zone of the bead.
Grâce au phénomène de rotation de la zone basse du bourrelet, ces derniers, notamment au niveau des sièges, appuient davantage sur la face d'appui correspondante des jantes, ce qui permet d'augmenter la cohésion au niveau de l'interface jante/pneumatique. Cet aspect est particulièrement important, par exemple lorsqu'un véhicule effectue des virages serrés ou encore des virages à haute vitesse. Ces caractéristiques contribuent donc à améliorer la sécurité de l'ensemble pneumatique/jante et donc du véhicule.Thanks to the phenomenon of rotation of the lower zone of the bead, the latter, in particular at the level of the seats, press more on the corresponding bearing face of the rims, which makes it possible to increase the cohesion at the level of the rim / tire interface. . This is particularly important, for example when a vehicle is making tight turns or even turning at high speed. These characteristics therefore contribute to improving the safety of the tire / rim assembly and therefore of the vehicle.
Pour faciliter la rotation ou permettre que celle-ci soit plus importante on prévoit sur le bourrelet une zone tampon entre la zone de mélange à haut module et le rebord de la jante.To facilitate rotation or allow it to be greater, a buffer zone is provided on the bead between the high modulus mixing zone and the rim flange.
Cette zone d'écrasement 17 est constituée d'un matériau plus souple que celui étant généralement situé dans la zone d'interface entre l'arrangement 11 de fils et la structure de renfort 2. Tel que décrit préalablement, sous l'effet combiné de la pression du pneumatique et d'une tension T agissant sur la structure 2, le moment M ainsi créé agit de façon à écraser la zone 17, favorisant de ce fait la rotation de la zone basse du bourrelet.This crushing zone 17 is made of a more flexible material than that generally located in the interface zone between the arrangement 11 of wires and the reinforcement structure 2. As previously described, under the combined effect of the pressure of the tire and of a tension T acting on the structure 2, the moment M thus created acts so as to crush the zone 17, thereby favoring the rotation of the lower zone of the bead.
Les différents exemples de réalisations décrites et/ou illustrées peuvent avantageusement être réalisées avec des dispositifs du type de ceux décrits dans le document EP 0 580 055.The various examples of embodiments described and / or illustrated can advantageously be carried out with devices of the type of those described in document EP 0 580 055.
Ainsi par exemple, il est très avantageux de confectionner le pneumatique sur un noyau central imposant la forme de sa cavité intérieure. On applique sur ce noyau, de préférence dans l'ordre requis par l'architecture finale, tous les constituants du pneumatique, qui sont disposés directement à leur place finale, selon un profil sensiblement final. Dans ce cas, un tel pneumatique peut être moulé et vulcanisé comme exposé dans le document US 4 895 692. For example, it is very advantageous to make the tire on a central core imposing the shape of its internal cavity. We apply to this core, preferably in the order required by the final architecture, all the components of the tire, which are arranged directly in their final place, according to a substantially final profile. In this case, such a tire can be molded and vulcanized as described in document US 4,895,692.

Claims

REVENDICATIONS
1. Pneumatique pour roue de véhicule, comprenant:1. Tire for vehicle wheel, comprising:
-deux flancs espacés axialement l'un de l'autre, réunis à leurs portions radialement extérieures par une zone de sommet pourvue sur sa portion radialement extérieure d'une bande de roulement circonférentielle ;-two sides spaced axially from one another, joined to their radially outer portions by a crown zone provided on its radially outer portion with a circumferential tread;
-des bourrelets, disposés radialement intérieurement à chacun des flancs, chaque bourrelet comportant un siège et un rebord externe destinés à venir en contact avec une jante adaptée ;-beads, arranged radially inside each of the sidewalls, each bead comprising a seat and an external flange intended to come into contact with a suitable rim;
-une structure de renfort s'étendant sensiblement radialement depuis chacun des bourrelets, le long des flancs, vers la zone sommet ;a reinforcing structure extending substantially radially from each of the beads, along the flanks, towards the crown area;
- au moins un desdits bourrelets comprenant :- at least one of said beads comprising:
- un siège de bourrelet comportant une génératrice dont l'extrémité axialement intérieure est sur un cercle de diamètre supérieur au diamètre du cercle sur lequel se trouve l'extrémité axialement extérieure ;- a bead seat comprising a generator whose axially inner end is on a circle of diameter greater than the diameter of the circle on which the axially outer end is located;
- une zone d'ancrage de la structure de renfort dans ledit bourrelet, comprenant un arrangement sensiblement radial de fils circonférentiels disposé de façon sensiblement adjacente à une portion de la structure de renfort et comprenant au moins deux piles réparties de part et d'autre de la structure de renfort, un mélange de liaison étant disposé entre les fils circonférentiels et la structure de renfort ;a zone for anchoring the reinforcement structure in said bead, comprising a substantially radial arrangement of circumferential wires disposed substantially adjacent to a portion of the reinforcement structure and comprising at least two stacks distributed on either side of the reinforcement structure, a connection mixture being arranged between the circumferential wires and the reinforcement structure;
- une zone de « montage/démontage » disposée sensiblement adjacente au siège du bourrelet, radialement intérieurement à la zone d'ancrage, et dont la distance correspond sensiblement à la distance BS-BC, où BS est la base du siège et BC est la base du crochet de jante.- an “assembly / disassembly” zone disposed substantially adjacent to the seat of the bead, radially inside the anchoring zone, and the distance of which corresponds substantially to the distance BS-BC, where BS is the base of the seat and BC is the rim hook base.
2. Pneumatique pour roue de véhicule selon la revendication 1 , comprenant également :2. Tire for vehicle wheel according to claim 1, comprising also:
- une zone intermédiaire, disposée sensiblement axialement extérieurement à la zone d'ancrage et comportant au moins une portion sensiblement alignée radialement avec la zone d'ancrage ;- An intermediate zone, arranged substantially axially outside the anchoring zone and comprising at least one portion substantially aligned radially with the anchoring zone;
5 - une zone d'appui dudit bourrelet susceptible de reposer directement ou indirectement contre le siège de jante adapté, et comprenant au moins une portion axialement alignée avec la zone intermédiaire et radialement intérieure à cette zone ;5 - a support zone of said bead capable of resting directly or indirectly against the adapted rim seat, and comprising at least one portion axially aligned with the intermediate zone and radially internal to this zone;
- ladite zone ' de « montage/démontage » étant disposée sensiblement 10 axialement intérieurement à la zone d'appui.- said zone 'of' assembly / disassembly "being disposed substantially 10 axially inwardly of the bearing zone.
3. Pneumatique pour roue de véhicule selon la revendication 1 ou 2, dans lequel la zone de montage/démontage forme un prolongement radialement intérieur à la zone d'ancrage.3. A tire for a vehicle wheel according to claim 1 or 2, in which the assembly / disassembly zone forms an extension radially inside the anchoring zone.
4. Pneumatique pour roue de véhicule selon l'une des revendications 2 ou 3, 15. dans lequel le matériau de la zone de montage démontage comporte un module sensiblement inférieur à celui du matériau de la zone d'appui. 4. Tire for vehicle wheel according to one of claims 2 or 3, 15. wherein the material of the disassembly mounting area has a modulus substantially lower than that of the material of the bearing area.
PCT/EP2003/004418 2002-04-29 2003-04-28 Tyre with bead provided with a zone facilitating mounting/dismounting WO2003093033A1 (en)

Priority Applications (1)

Application Number Priority Date Filing Date Title
AU2003227686A AU2003227686A1 (en) 2002-04-29 2003-04-28 Tyre with bead provided with a zone facilitating mounting/dismounting

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
FR0205475 2002-04-29
FR02/05475 2002-04-29

Publications (1)

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WO2003093033A1 true WO2003093033A1 (en) 2003-11-13

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WO (1) WO2003093033A1 (en)

Citations (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
WO2001040000A1 (en) * 1999-12-03 2001-06-07 Societe De Technologie Michelin Tyre bead with extended mobility
US20020023700A1 (en) * 1998-06-05 2002-02-28 Renato Caretta Method for manufacturing a tyre for vehicle wheels, tyre which can be obtained by said method, and vehicle wheel comprising said tyre

Patent Citations (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US20020023700A1 (en) * 1998-06-05 2002-02-28 Renato Caretta Method for manufacturing a tyre for vehicle wheels, tyre which can be obtained by said method, and vehicle wheel comprising said tyre
WO2001040000A1 (en) * 1999-12-03 2001-06-07 Societe De Technologie Michelin Tyre bead with extended mobility

Also Published As

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