Classifications

• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B60—VEHICLES IN GENERAL
  • B60C—VEHICLE TYRES; TYRE INFLATION; TYRE CHANGING; CONNECTING VALVES TO INFLATABLE ELASTIC BODIES IN GENERAL; DEVICES OR ARRANGEMENTS RELATED TO TYRES
  • B60C15/00—Tyre beads, e.g. ply turn-up or overlap
  • B60C15/0009—Tyre beads, e.g. ply turn-up or overlap features of the carcass terminal portion
  • B60C15/0018—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
  • B60C15/024—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
  • B60C15/00—Tyre beads, e.g. ply turn-up or overlap
  • B60C15/04—Bead cores
• • 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
  • B60C9/023—Carcasses built up from narrow strips, individual cords or filaments, e.g. using filament winding
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B60—VEHICLES IN GENERAL
  • B60C—VEHICLE TYRES; TYRE INFLATION; TYRE CHANGING; CONNECTING VALVES TO INFLATABLE ELASTIC BODIES IN GENERAL; DEVICES OR ARRANGEMENTS RELATED TO TYRES
  • B60C2200/00—Tyres specially adapted for particular applications
  • B60C2200/02—Tyres specially adapted for particular applications for aircrafts
• • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
  • Y10—TECHNICAL SUBJECTS COVERED BY FORMER USPC
  • Y10T—TECHNICAL SUBJECTS COVERED BY FORMER US CLASSIFICATION
  • Y10T152/00—Resilient tires and wheels
  • Y10T152/10—Tires, resilient
  • Y10T152/10495—Pneumatic tire or inner tube
  • Y10T152/10765—Characterized by belt or breaker structure
• • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
  • Y10—TECHNICAL SUBJECTS COVERED BY FORMER USPC
  • Y10T—TECHNICAL SUBJECTS COVERED BY FORMER US CLASSIFICATION
  • Y10T152/00—Resilient tires and wheels
  • Y10T152/10—Tires, resilient
  • Y10T152/10495—Pneumatic tire or inner tube
  • Y10T152/10819—Characterized by the structure of the bead portion of the tire
• • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
  • Y10—TECHNICAL SUBJECTS COVERED BY FORMER USPC
  • Y10T—TECHNICAL SUBJECTS COVERED BY FORMER US CLASSIFICATION
  • Y10T152/00—Resilient tires and wheels
  • Y10T152/10—Tires, resilient
  • Y10T152/10495—Pneumatic tire or inner tube
  • Y10T152/10819—Characterized by the structure of the bead portion of the tire
  • Y10T152/10846—Bead characterized by the chemical composition and or physical properties of elastomers or the like

Definitions

• the invention relates to mounted assemblies for aircraft and the wheels and tires which constitute them.
• the assembled assemblies for aircraft concerned by the invention are characterized in particular by the combination of inflation pressure greater than 9 bars and a relative deflection of the tire greater than 30%.
• the deflection of a tire is defined by the radial deformation of the tire, or variation of the radial height, when the latter passes from an unloaded state, to a static loaded state, under nominal load and pressure conditions. .
• the reinforcement or reinforcement of tires and in particular aircraft tires is currently - and most often - consists of a ply or a stack of several plies conventionally designated “carcass plies”, “ summit tablecloths, 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 often longitudinal wire reinforcements, 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.
• finishing are then applied to the blank, to obtain a product ready for vulcanization.
• an anchoring element generally a bead wire
• Such a “conventional” type of process 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 carcass reinforcement in the tire bead area.
• an anchoring element generally a bead wire
• a portion of each of 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 conventional terms such as “tablecloths”, “rods”, etc.
• the term “carcass-type reinforcement” or “sidewall reinforcement” is valid for designating the reinforcing elements of a carcass ply in the conventional process, and the corresponding reinforcing elements, generally applied at the sidewalls, d '' a tire produced using a semi-finished process.
• axial means a direction parallel to the axis of rotation of the tire; this direction can be “axially interior” when it is directed towards the interior of the tire and “axially exterior” when it is directed towards the exterior of the tire.
• Ring is understood to mean a direction perpendicular to the axis of rotation of the tire and passing through this axis of rotation. This direction can be “radially inside” or “radially outside” depending on whether it is directed towards the axis of rotation or towards the outside of the tire.
• a radially oriented reinforcing element means a reinforcing element contained substantially in the same axial plane.
• a circumferentially oriented reinforcing element means a reinforcing element oriented substantially parallel to the circumferential direction of the tire, that is to say making an angle with this direction not deviating by more than five degrees from the circumferential direction.
• the term “reinforcing element” means both monofilaments and multifilaments, or assemblies such as cables, plies or any other equivalent type of assembly, whatever the material and the treatment of these reinforcing elements, for example surface treatment or coating or pre-gluing to promote adhesion to the rubber.
• modulus of elasticity of a rubbery mixture is understood to mean a secant module of extension at 10% deformation and at room temperature; the measurement is carried out after a first accommodation cycle up to 10% deformation:
• Tg glass transition temperature of an elastomer is understood to mean the glass transition temperature thereof measured by differential thermal analysis.
• Static creep test means a test in which test pieces are prepared, the useful part of which has a length of 70 mm, a width of 5 mm and a thickness of 2.5 mm (these test pieces are cut from vulcanized plates 2.5 mm thick); the test pieces are placed in an oven at 150 ° C. and a mass of 3 kg is immediately attached to them; the test is thus carried out with an initial constraint of:
• the “static fogging rate” corresponds to the variation in deformation in a given time, for example between 3 and 5 hours of testing:
• rheometry test means an alternating shear test at a deformation of ⁇ 0.2 degrees, a frequency of 100 cycles / min, a temperature of 197 ° C and a duration of 10 min; Monsanto rheometer; the test is carried out on a raw mixing disc, the evolution over the course of 10 min is recorded of the torque resulting from the shearing imposed between the two faces of the disc; the evolution of the torque after the measured maximum is particularly noted here; if the measured torque remains stable, there is no reversion, that is to say a reduction in the stiffness of the test piece, if the measured torque decreases, it is indicated that there is a reversion; the phenomenon of reversion reflects a reduction in the rigidity of the test piece under the conditions of the test; it is a test of the thermal stability of the mixture at high temperature; we notice :
• breaking strength maximum load in N
• breaking strength in MPa
• elongation at break total elongation in%
• the mechanical properties are measured on fibers which have been subjected to prior conditioning.
• Pre-conditioning means storing the fibers for at least 24 hours, before measurement, in a standard atmosphere according to the European standard DIN EN 20139 (temperature of 20 ⁇ 2 ° C; humidity of 65 ⁇ 2%).
• the mechanical properties in extension are measured in a known manner using a ZWICK GmbH & Co (Germany) type 1435 or type 1445 traction machine.
• the fibers after having received a small preliminary protective twist (helix angle of approximately 6 °), undergo a traction over an initial length of 400 mm at a nominal speed of 200 mm / min. All results are an average of 10 measurements.
• Tires can, as previously stated, adopt different types of construction.
• US Patent 4,832,102 describes for example an airplane tire comprising a crown, two sidewalls and two beads, a carcass reinforcement and a crown reinforcement in which the carcass reinforcement comprises two circumferential alignments of reinforcements of high elasticity modulus , anchored in the two beads, and the crown reinforcement comprises at least one working block with at least one ply of reinforcements of high elasticity modulus.
• the carcass reinforcement is anchored in the beads by the inversion, around a rod, of the two circumferential alignments of first reinforcements of high elasticity modulus.
• Patent WO 02/00456 describes another type of tire for aircraft, the carcass reinforcement of which comprises two or three circumferential alignments of reinforcement elements of high elasticity modulus and anchoring means of said reinforcement elements, constituting the carcass reinforcement in each bead.
• the anchoring means according to this document consist of circumferentially oriented wires axially bordering the circumferential alignments of the reinforcement elements of the carcass reinforcement, said carcass reinforcement elements and the circumferentially oriented wires being separated by a mixture rubbery binding with very high modulus of elasticity.
• the use of wires makes it possible to obtain satisfactory rigidity with the smallest possible size of the bead; the compactness of the bead is essential for airplane tires in order to reduce the consequences of the heating of said beads.
• Aircraft tires must withstand extreme conditions in service, in particular in terms of applied load and speed, given their low mass and size. As a result, despite their very high inflation pressures, greater than 9 bars, their crushing or deflection in service can commonly reach values twice that observed for heavy-duty or passenger car tires.
• the assembled assemblies thus produced for aircraft require strict, rigorous and frequent examinations. These checks may be accompanied by a dismantling of the assembled assembly and a dissociation of the wheel and the tire. These technical operations are long and require the intervention of a highly qualified workforce.
• the object of the invention is in particular to provide a mounted assembly for an aircraft which facilitates these technical checks and more particularly which facilitates the disassembly and reassembly of the assembled assemblies during the life of an aircraft tire.
• an assembly mounted for an aircraft consisting of a wheel and a tire comprising in particular beads, the inflation pressure of which is greater than 9 bars and whose relative deflection is greater at 30% o, said wheel comprising a rim for receiving the tire and more specifically seats receiving the beads of said tire, said rim comprising a hollow base functionality.
• the rim is of the monobloc type.
• a hollow base functionality must be understood to mean that the wheel has a structure conferring a functionality comparable to that of a hollow base of a usual monobloc rim for applications other than those of the airplane; the function of a hollow base is in particular to authorize the fitting of a tire in combination with a certain deformation of the beads thereof.
• This mounting method is entirely conventional in applications other than those of the airplane. In these other applications, it is usual, for mounting a tire on a monobloc wheel, to provide in the part located between the seats of the wheel a recess area or hollow base which makes it possible to successively receive a part of each of the tire beads for mounting.
• the beads of the tire of the assembly mounted according to the invention are advantageously ovalizable, that is to say deformable in their plane, preferably under industrially acceptable forces.
• the beads of the tire of the assembly mounted according to the invention can be warped, that is to say whose perimeter is deformable in the axial direction.
• the Applicant has found that, by acting on certain criteria, it is also possible to produce mounted assemblies for aircraft, the tires of which are suitable for mounting on a rim comprising a hollow base functionality.
• the assembly and disassembly of the assemblies mounted according to the invention can thus be carried out in a simpler and faster way than when it is a wheel made up of several parts. Indeed, the tools and skills required for these operations are simpler than according to the assemblies and disassembly usually practiced. This of course has economic benefits of various kinds with regard to. the direct means of implementation and the manpower and its necessary training.
• the possibility of mounting an aircraft tire on a one-piece type wheel can make it possible to constitute an assembly assembled according to the invention, the mass of which is substantially less than the mass of a conventional assembly assembled, the wheel of which is made up of several parts.
• This can also lead to substantial economic advantages, the gain in mass of the assembled assembly being able to result in an increase in the transportable mass or in a reduction in the fuel consumption of the aircraft.
• the usual method of mounting a tubeless tire on a monobloc rim comprising a hollow base for applications other than aircraft applications consists of different steps which are as follows; we start by passing part of the first bead over the rim flange and we place this part in the hollow base.
• the invention provides that this hollow base functionality can be fulfilled for example by a limited recess area on the periphery of the wheel or even by one or more openings limited on the periphery of the wheel.
• the invention advantageously provides that the braking system is integrated into the wheel by closing off the said opening or openings. This closure of the opening or openings can make it possible to play the role of anti-planing device; closing the opening (s) makes the hollow base functionality necessary for dismantling the tire or removing it disappear. Such a system can therefore possibly make it possible to have no humps.
• the invention provides that the openings ensuring the hollow base functionality can be closed by any means known to those skilled in the art as soon as they have fulfilled their function during mounting of the tire.
• the invention also provides that the means ensuring the hollow base functionality can constitute a part of the braking device which is integrated inside the wheel.
• the seats of the rim of the wheel of the mounted assembly have a slope of 5 °.
• the seats of the rim of the wheel of the mounted assembly have a slope greater than 5 ° and preferably less than 15 °.
• a first alternative embodiment of the invention advantageously provides that, the tire comprising a crown, two sidewalls and two beads, a carcass reinforcement anchored in the two beads and a crown reinforcement, in which the carcass reinforcement comprises at least a circumferential alignment of reinforcement elements and in which the means for anchoring said reinforcement elements in each bead comprise at least one reinforcement element oriented circumferentially, the carcass reinforcement of the tire comprises at least one layer of reinforcement elements having a turning area around at least one circumferentially oriented reinforcement element.
• the assembled assembly comprises an airplane tire in which the carcass reinforcement is anchored in the beads by turning around around at least one circumferentially oriented reinforcement element, such as a rod.
• a second alternative embodiment of the invention advantageously provides that, the tire comprising a crown, two sidewalls and two beads, a carcass reinforcement anchored in the two beads and a crown reinforcement, in which the carcass reinforcement comprises at least a circumferential alignment of reinforcement elements and in which the means for anchoring said reinforcement elements in each bead comprise at least one circumferentially oriented reinforcement element, the means for anchoring said reinforcement elements in each bead of the tire comprise elements of circumferentially oriented reinforcement axially bordering said circumferential alignments of said reinforcing elements of the carcass reinforcement.
• the invention also provides an aircraft wheel comprising a rim for receiving a tire, comprising in particular beads, and more specifically seats receiving the beads of said tire, the inflation pressure of the mounted assembly consisting of the wheel and said tire being greater than 9 bars and having a relative deflection greater than 30%, said rim comprising a hollow base functionality.
• the rim of the wheel according to the invention is of the one-piece type.
• the seats of the wheel rim have a slope of 5 °.
• the seats of the rim of the wheel have a slope greater than 5 ° and preferably less than 15 °.
• the invention also proposes an aircraft tire, the inflation pressure of which is greater than 9 bars and whose relative deflection is greater than 30%, comprising a crown, two sidewalls and two beads, a carcass reinforcement anchored in the two beads and a crown reinforcement, in which the carcass reinforcement comprises at least one, and preferably at least two, circumferential alignments of reinforcement elements and in which the means for anchoring said reinforcement elements in each bead comprise at least one circumferentially oriented reinforcement element, the beads of the tire being ovalizable, that is to say deformable in their plane, preferably under industrially acceptable forces.
• the beads of the tire can be warped, that is to say of which the perimeter is deformable in the axial direction.
• the invention also provides an aircraft tire, the inflation pressure of which is greater than 9 bars and whose relative deflection is greater than 30%, comprising a crown, two sidewalls and two beads, a carcass reinforcement anchored in the two beads and a crown reinforcement, in which the carcass reinforcement comprises at
• the tire thus defined according to the invention has beads whose lower rigidity compared to the aircraft tires usually produced makes it easier to assemble and disassemble said aircraft tire. Surprisingly, the Applicant has found that this rubber anchoring mixture makes it possible, despite its rigidity much lower than what was previously recommended, to retain characteristics, particularly in endurance of the beads concerned, which are very satisfactory.
• the anchoring rubber mix comprises at least one synthetic elastomer included in the group of "SBR” or copolymer butabiène-styrene, and "BR", or polybutadienes with a total proportion of synthetic elastomer greater than 50% of the total mass of elastomers.
• the total proportion of synthetic elastomer is between 55 and 65% of the total mass of elastomers. Above 65%, the raw tack of the bonding gums becomes insufficient and this poses problems of making tire beads, on the other hand, below 55%>, the resistance of the rubber anchoring mixtures to a stress static fogging at high temperature degrades.
• the rubbery anchoring mixture preferably comprises an SBR of Tg of between -70 ° and -25 ° C with a proportion by mass greater than 20%> of the total mass of elastomers.
• It can also include a BR of Tg of between -110 ° and -90 ° C with a proportion by mass of less than 40% of the total mass of elastomers.
• the presence of BR improves the thermal stability of the rubber anchoring mixture at high temperature, however, beyond 40% of the total mass of elastomers, the rubber anchoring mixture becomes difficult to produce.
• the rubbery anchoring mixture withstands without breaking a static fogging stress at 150 ° C. under an initial stress of .2.35 MPa for at least 5 hours.
• the rubbery anchoring mixture has a static fogging rate at
• said rubbery anchoring mixture has a rate of reversion after 10 min at 197 ° C of less than 10% and preferably less than 5%.
• the carcass reinforcement of the tire comprises at least one layer of reinforcing elements having a turning area around at least one circumferentially oriented reinforcement element, such as a rod.
• the rubber mixture according to the invention makes it possible to confer, as previously stated, a certain flexibility on the bead which facilitates the mounting and dismounting of the tire.
• the rubber mixture when the carcass reinforcement is turned around a rod, the rubber mixture is advantageously present, in addition to the area between the rod and the carcass reinforcement, within the rod, between the various reinforcing elements constituting it.
• it can also advantageously be provided to subdivide the bead or bows to increase the proportion of rubber mixture according to the invention relative to the proportion of reinforcing element in a given zone. This can result in the presence of numerous subdivisions of rods arranged in an organized or unorganized manner.
• the rod (s) can be made up of wires or cables chosen from the group of carbon, tungsten, aramid, glass fiber or steel reinforcements.
• a second embodiment of the invention it applies to an aircraft tire in which the carcass reinforcement is anchored in the beads by means of circumferentially oriented reinforcing elements axially bordering said reinforcing elements of the carcass reinforcement.
• said rubber mixture according to the invention provides sufficient flexibility for improve the conditions for mounting and dismounting aircraft tires on their wheels.
• the invention advantageously provides that the circumferential reinforcing elements are cables.
• said cables have an ability to penetrate between 80 and 100%), the breaking force of said cables being greater than 150 daN and said cables having an elongation at break greater than 4%.
• the use of cables makes it possible to improve and facilitate the manufacture of the tires according to the invention according to manufacturing technologies of the type on toroidal core.
• the Applicant has found that the fact of replacing, in the tire according to the invention, an anchoring of the carcass reinforcement by means of circumferential wires coupled to the reinforcing elements of the carcass reinforcement by means of a rubber mix of anchoring, by anchoring by means of cables as defined above makes it possible to improve the yield of the manufacturing process.
• the use of the cables defined according to the invention makes it possible to maintain a compactness of the beads of the tire for satisfactory rigidity for the applications considered.
• cables as circumferential reinforcing elements according to this second embodiment of the invention allows warping of the beads of the tire or deformation of the perimeter in the axial direction. Such a deformation further promotes the mounting and dismounting of aircraft tires according to the invention. Such deformation also allows, under very simple conditions, the mounting and dismounting of tires on one-piece rims, that is to say in a single part.
• a rod consisting of wires or cables, associated with a rubber mixture according to the invention present in the area between the bead wire and the carcass reinforcement and / or within the bead wire, between the various reinforcing elements constituting it, also allows the mounting and dismounting of tires on one-piece rims.
• a rod consisting of wires or cables, associated with a rubber mixture according to the invention present in the area between the bead wire and the carcass reinforcement and / or within the bead wire, between the various reinforcing elements constituting it, also allows the mounting and dismounting of tires on one-piece rims.
• such operations require greater efforts than in the case mentioned above according to the second embodiment of the invention.
• the ability to penetrate according to the invention is the ability of the rubber to penetrate the free areas of a cable, that is to say the areas containing no material; it is expressed as a percentage of said free areas occupied by gum after cooking and determined by a test of air permeability.
• This air permeability test measures a relative index of air permeability. It constitutes a simple means of indirect measurement of the penetration rate of the cable by a rubber composition. It is carried out on cables extracted directly, by shelling, from the vulcanized rubber sheets which they reinforce, therefore penetrated by the cooked rubber.
• the test is carried out on a determined cable length (for example 2 cm) as follows: air is sent to the cable inlet, under a given pressure (for example 1 bar), and the quantity is measured air at the outlet, using a flow meter; during the measurement, the cable sample is locked in a tight seal so that only the quantity of air passing through the cable from one end to the other, along its longitudinal axis, is taken into account by the measurement.
• the measured flow rate is lower the higher the penetration rate of the cable by the rubber.
• the elongation at break values according to the invention allow optimization of the working efficiency of the cables.
• the cables are wound circumferentially to form several radially concentric or helical turns allowing better anchoring between the cables and the reinforcing elements of the carcass reinforcement.
• the elongation at break values of the cables according to the invention allow a deformation of said cables which leads to a greater efficiency of said turns.
• the deformation of said cables according to the invention makes it possible to obtain a more homogeneous, according to the winding length, of the stresses supported by the same winding of such a cable which does not have said elongation characteristics.
• the breaking force of the cables is less than 400 daN.
• a breaking force greater than such a value can lead, in particular in the case of an overall breaking force value of the fixed bead and of a diameter of imposed cables, to a reduction in the number of turns of said cables and therefore to a reduction in the anchoring height between the reinforcing elements of the carcass structure and the circumferentially oriented cables.
• Such a reduction in the anchoring height can be detrimental to the quality of said anchoring.
• the increase in the breaking strength of the cables is combined with an increase in the diameter of said cables, this can cause problems of bulk, in particular in terms of widening of the lower zone.
• the elongation at break of the cables is less than 8%.
• a higher elongation could lead to tires whose stiffness of the beads, for high pressures, is not sufficient to guarantee the holding of said tire on a rim and to guarantee the transmission of braking torques.
• the elongation at break values of the cables according to the invention are advantageously obtained by heat treatments of cables qualified as "large elongation" treatment. Such treatments known to those skilled in the art are for example described in European patent EP 0 751 015.
• the cables according to the invention comprise a conventional adhesive coating such as a brass coating so as to improve the adhesion between said cables and the rubber mixtures.
• the circumferentially oriented cables preferably have an extension module greater than that of the reinforcing elements of the carcass reinforcement. They are preferably chosen from the group of carbon, tungsten, aramid, fiberglass or steel reinforcements.
• Compliance with these limits for the ratio between the total extension rigidity of the circumferentially oriented cables arranged inside the carcass reinforcement in each bead and the total extension rigidity of the circumferentially oriented cables disposed outside of the carcass reinforcement has the advantage of making the stress of the cables oriented circumferentially in the bead more homogeneous, whatever their position.
• This line CD substantially defines a very rigid embedding zone, where the deformations are very reduced and a bending zone radially above CD. The fact that all the circumferentially oriented cables are in the embedding area increases the endurance of the bead.
• the bead of the tire according to the invention having an outer surface intended to come into contact with the corresponding surface of the seat and of the rim hook, after mounting on said rim and inflation of the tire, the contact zone between the surface outside of the bead and the rim extends at least to point B of the hook of maximum radius Rj.
• ⁇ being the diameter of the circumference of the outer surface of the bead intended to come to bear against the circumference of the hook of the rim of maximum radius Rj, we have:
• the reinforcing elements constituting the carcass reinforcement can be any type of reinforcing elements in wire form, capable of reinforcing a determined matrix, for example a rubber matrix.
• reinforcing elements mention may be made, for example, of multifilament fibers (“multifilament yarns”), these fibers being able to be twisted or not on themselves, individual threads such as cylindrical or oblong monofilaments, with or without twisting themselves, cords or twists (“cords”) obtained by wiring or twisting operations of these unitary threads or of these fibers, such reinforcing elements being able to be hybrid, that is to say composite, comprising elements of different natures.
• “Plied yarn” or “folded yarn” is understood to mean a reinforcing element constituted by two strands (“single yarns”) or more assembled together by twisting operations; these strands, generally formed of multifilament fibers, are first individually twisted in one direction (direction of torsion S or Z) during of a first twisting step, then twisted together in the opposite direction (direction of twist Z or S, respectively) during a second twisting step.
• the reinforcing elements constituting the carcass reinforcement are, for example, made of aromatic polyamide or reinforcing elements such as those described in patent application WO 02/085646. It can be wires or cables.
• the carcass reinforcement of the tires according to the invention comprises two or three circumferential alignments of reinforcing elements for example.
• each circumferential alignment of the carcass reinforcement is, in each bead, bordered axially internally and axially externally by cables oriented circumferentially.
• the reinforcing elements of the carcass reinforcement form back and forth arrangements arranged adjacent, with, at the level of each bead, loops connecting each times a go to a return.
• the crown reinforcement of the aircraft tire according to the invention preferably comprises at least one working block with one or more layers of parallel reinforcing elements in each layer, oriented substantially circumferentially ; it is advantageously reinforcing elements consisting of aromatic polyamide, or reinforcing elements such as those described in patent application WO 02/085646.
• the crown reinforcement comprising a central zone and two lateral zones
• the working block further comprises at least two layers of reinforcing elements, oriented substantially circumferentially, arranged axially on either side of the median plane of the pneumatic in the lateral zones of said apex.
• These layers make it possible to withstand the forces due to centrifugation at high speed. They are preferably arranged radially internally relative to the two layers of elements. circumferentially oriented reinforcement of the working block.
• These two reinforcing layers have the advantage of increasing the hooping of the lateral zones of the crown without increasing its thickness.
• the crown reinforcement may also further comprise at least two layers of reinforcing elements, mutually parallel in each layer and crossed from one layer to the next, making with the circumferential direction an angle ⁇ , between 5 ° and 35 ° to reinforce the rigidity of the tire drift.
• the reinforcing elements are, for example, reinforcing elements such as those described in patent application WO 02/085646.
• the crown reinforcement may also include, disposed radially outward relative to the working block, a protective crown layer. This protective layer preferably extends axially beyond the axial width of the layers of reinforcement elements of circumferential orientation.
• the aircraft tire according to the invention is particularly advantageous for constituting an assembly mounted with a one-piece type wheel.
• the possible deformation of the beads of the tire makes it possible in particular to mount and dismount the tire on such a wheel.
• these assembly and disassembly can be carried out in a simpler and faster way than when it is a wheel made up of several parts. This has economic advantages of various kinds, in particular with regard to the direct means of implementation and the manpower and its necessary training as mentioned above.
• the invention thus proposes the use of a tire as it has just been described in an assembly mounted for an aircraft as described above, the rim of which is of the one-piece type comprising a hollow base functionality.
• the invention also proposes the use of a tire in a mounted assembly for an aircraft as described above, the wheel of which is of the monobloc type comprising a hollow base functionality, said tire comprising at least one any of the characteristics of the tire according to the invention as described above.
• the invention also proposes a use of a tire as it has just been described in a mounted assembly for an airplane whose inflation pressure is greater than 9 bars and whose relative deflection is greater than 30%, consisting of a wheel and the tire, said wheel comprising a rim for receiving the tire and more specifically seats receiving the beads of said tire, said wheel being of the multi-part type.
• the invention also proposes the use of a tire in a mounted assembly for an airplane whose inflation pressure is greater than 9 bars and whose relative deflection is greater than 30%, consisting of a wheel and the tire, said wheel comprising a rim for receiving the tire and more specifically seats receiving the beads of said tire, said wheel being of the multi-part type, said tire comprising at least any one of the characteristics of the tire according to the invention as described above.
• the invention also provides an assembled assembly for an airplane, the inflation pressure of which is greater than 9. bars and the relative deflection of which is greater than 30%), consisting of a wheel and a tire as described above, comprising in particular beads, said wheel comprising a rim for receiving the tire and more specifically seats receiving the beads of said tire, said wheel being of the multi-part type.
• the tire according to the invention also has advantages with regard to the mounting and dismounting of the assembly assembled in the case of a wheel in several parts.
• the flexibility of the beads of the aircraft tire according to the invention will make it possible to facilitate the positioning of the tire during mounting by reducing the risks of degradation of the latter.
• the tire according to the invention makes it possible to facilitate the dismantling operations of such mounted assemblies.
• the extreme conditions of use of these mounted assemblies lead to a very strong connection between the tire and the rim which requires exerting on said tire significant forces; these must be exerted very homogeneously on the periphery of the sidewall of the tire when the latter has rigid beads at the risk of blocking the assembled assembly as soon as the bead is positioned at an angle relative to the rim of the wheel.
• this operation is simplified due to the flexibility of the beads of the tire.
• the tools and the qualification of the workforce may thus be less specialized in the case of the invention.
• FIGS. 1 to 7 represent:
• FIG. 1 a schematic view in axial section of a tire according to the invention
• FIG. 4 a schematic representation of a bead according to a second embodiment of the invention
• FIG. 5 a schematic view in axial section of a tire according to an alternative embodiment of the invention shown in FIG. 1,
• FIG. 6 a schematic view in axial section of a tire according to another alternative embodiment of the invention shown in FIG. 1,
• FIG. 7a, 7b, 7c the steps of mounting a tire on a rim to form an assembly mounted according to the invention.
• Figures 1 to 7 are not shown to scale to simplify understanding.
• the airplane tire 1 shown diagrammatically in axial half-section in FIG. 1 comprises a crown 2, two sidewalls 3 and two beads 4.
• a carcass reinforcement 5 extends from one bead 4 to the other and is formed of two circumferential alignments 6 and 7 of reinforcing elements.
• the circumferential alignments of reinforcing elements 6 and 7 are oriented radially in the sidewalls 3 and consist of reinforcing elements made of aromatic or ara ide polyamide.
• the reinforcing elements are arranged in parallel and are separated by a mixture layer 8, the nature and module of which are adapted as a function of their position in the tire.
• the two circumferential alignments 6 and 7 are anchored in the beads
• the tension which develops in the radial reinforcing elements during inflation of the tire 1 is taken up in particular by the lateral adhesion between each circumferential alignment 6 and 7 and the stacks 9 of cables circumferentially oriented.
• This bead structure provides excellent anchoring which remains very effective even for the very high inflation pressures of aircraft tires, greater than 9 bars and which can reach 25 bars in certain particular applications.
• the tires have shown an ability to withstand four times the operating pressure as required by TSO C62.
• the stacks 9 of circumferentially oriented cables are divided into three groups, two stacks 11 arranged axially outside the carcass reinforcement 5 on the outside of the tire, two stacks 13 arranged axially internally relative to the carcass reinforcement 5, on the inside of the tire and 4 piles 12 arranged between the two circumferential alignments 6 and 7 of the carcass reinforcement 5.
• the invention may also provide for the placement of cones of rubber mixes axially between the carcass reinforcement and the stacks 9 of circumferentially oriented cables to allow the placement of circumferentially oriented cables such that the axial distance between them and the carcass reinforcement ' increases in the radial direction.
• This variant embodiment is not illustrated in the figures. Such placement of the cables has been described in French application FR 0209355.
• the number of turns of the batteries decreases progressively with the distance relative to the axis of rotation A of the tire 1. This results in a substantially conical shape in the arrangement of the cables oriented circumferentially. This has the advantage of strongly stabilizing the beads 4 during inflation of the tire and when passing through the contact area in service.
• All the turns of the batteries 9 are embedded in the rubbery mixture 10 of extension module with 10% deformation of between 10 and 20 MPa to ensure good recovery of the forces due to the inflation pressure and thus an excellent anchoring of the carcass reinforcement in the beads 4.
• the wires 81, 82 are made of steel with a carbon content of between 0.7 and 0.9%).
• the wires have been previously treated to have a brass coating promoting the adhesion of the wire to the rubber.
• the wires have a work hardening rate of less than 3.5.
• the cable has a total diameter D ′, corresponding to the diameter of the circumscribed circle 84 at the outer layer, equal to 1.35 mm. The measurement of the penetration ability of this cable made according to the method described above resulted in a value of 100%.
• the cable breaking force is 198 daN and its elongation at break is 5.4%.
• the elongation at break is obtained after a heat treatment such as that mentioned above; the heat treatment makes it possible to increase the elastic and plastic elongations which are added to the structural elongation.
• the latter is equal to 0.1% o for cable 80 of formula 9.35.
• Another layered cable, of formula 13.35 was tested; this cable is made up of 13 elementary wires of diameter equal to 35/100 mm and of formula 4 + 9, with 4 wires, constituting the first layer, twisted together to form a plied, and 9 wires, forming the outer layer, wound together helically around the first layer.
• the elementary wires are the same as in the previous case.
• the measurement of the penetration ability of this cable made according to the method described above. led to a value of 80%>.
• the breaking force of the cable is equal to 282 daN and its elongation at break of 6.4%. Note that the structural elongation of this cable of formula 13.35 is 0.2%.
• FIG. 4 illustrates a bead 21 and a sidewall 22 of a second embodiment of a tire 20 according to the invention in which the carcass reinforcement 23 consists of two circumferential alignments, 24, 25 of reinforcing elements in aromatic or aramid polyamide.
• the carcass reinforcement 23 consists of two circumferential alignments, 24, 25 of reinforcing elements in aromatic or aramid polyamide.
• the bead 21 are disposed stacks 27 of cables of circumferential orientation. These stacks 27 are here separated into three groups.
• the number of turns of circumferentially oriented cables is such that it is verified that the sum of the extension rigidities of the stacks arranged externally relative to the carcass reinforcement is substantially of the same order as the sum of the extension rigidities stacks arranged internally relative to the carcass reinforcement 23.
• the outer surface of the bead 21 comprises a seat 32, a frustoconical wall of substantially radial orientation 33 adjacent radially internally to a wall 34 whose section is an arc of a circle EF with center C.
• This CD line substantially defines an area very rigid installation where the deformations are very reduced and a bending zone radially above CD.
• the fact that all the circumferentially oriented reinforcing elements are in the embedding zone increases the endurance of the bead.
• This outer surface of the bead is intended to come to bear against the wall of a rim 35, the outer profile of which is also shown in FIG. 4.
• This profile comprises the seat 36 and the substantially radial wall of the hook 37 followed by the rim 38
• the rim 38 has a cross section in an arc of a circle with a center C.
• the point of greatest diameter is B, of radius Rj.
• the point E disposed on the axially outer surface of the bead 21 is intended to come into contact with substantially the point B.
• the surfaces 34 and 38 are homocentric, that is to say that their centers C and C are combined.
• the point E is arranged on a circumference of diameter ⁇ .
• ⁇ 2 (R j - ⁇ ) with ⁇ between 0.5 and 2 mm.
• crown reinforcement 14 This consists of a working block comprising two layers of reinforcing elements 15 and 16 of substantially circumferential orientation obtained by helical winding of at least one reinforcing element.
• the number of reinforcing layers as well as the laying pitch are adapted according to the size of the tire and its conditions of use.
• This embodiment of a crown reinforcement has the advantage of providing a very effective hooping which minimizes the variation of the dimensions of the tire during inflation as well as at high speed. It can be seen that the evolution of the profile can be three to four times lower than for a common aircraft tire such as an AIRX 30x8.8R15.
• This excellent hooping also has the advantage of not greatly expanding the mixtures constituting the tread of the top of the tire. Cracks on the surface of the tread due to ozone in the air are greatly reduced.
• the crown reinforcement 41 of the tire 40 presented in FIG. 5 comprises, as before, two layers of reinforcement elements of substantially circumferential orientation 15 and 16 and is completed by two layers 42 and 43 of reinforcement elements, oriented substantially circumferentially arranged axially on either side of the median plane of the tire in the lateral zones of the crown. They make it possible to reinforce the hooping of the lateral zones L of the top.
• the layers 42 and 43 are arranged radially between the layers 15 and 16 and the carcass reinforcement 5.
• the frame 41 is also completed by a protective top layer 44 disposed radially outwardly relative to the other layers of the top frame 41.
• This protective top layer may be made up of corrugated metal reinforcing elements so as not to be stressed in normal running. It should be noted that this protective layer extends axially beyond the layers 15 and 16 on either side of the median plane P of the tire by an axial distance a.
• FIG. 6 shows a tire 50 with a crown reinforcement 51 additionally comprising two layers 52, 53 of reinforcing elements, mutually parallel in each layer and crossed from one layer to the next, making an angle with the circumferential direction ⁇ , between 5 ° and 35 °. These two layers are arranged radially below the layers of circumferential reinforcing elements 15 and 16. They increase the drift thrust of the tire 30 relative to that of the tire 40.
• FIGS. 7a, 7b, 7c illustrate by sectional diagrams the steps for mounting a tire according to the invention on a wheel 72 of the one-piece type comprising a hollow base functionality represented by the recesses 73. The figures schematically represent only the beads 70, 71 of the tire according to the invention. In FIG.
• the diameter of the bead 70 corresponds substantially to the diameter W of the rim seat which is to receive the bead.
• FIG. 7b shows that it is the same for passing the second bead 71 over the rim 74 of the rim 72. Part of the second bead 71 is passed over the rim 74 and is now placed in the area in recess or hollow base 73. As previously for the bead 70, it is then possible to pass the rest of the bead 71 over the rim 74 by slightly ovalizing the corresponding bead of the tire, accompanied by warping of this one.
• FIG. 7c illustrates the end of the assembly by an inflation step at a pressure such that it will ensure the establishment of the beads 70, 71 on the seats 75, 76 bearing on the flanged edges.
• a rubber anchoring mixture containing a synthetic “SBR” elastomer, or butadiene-styrene copolymer, of Tg between ⁇ 70 can be used. ° and -30 ° C, used alone or in combination with "BR", or polybutadiene.
• the BR has a Tg of between -110 ° and -90 ° C.
• the synthetic elastomer (s) are used in a totalized proportion of at least 50% of the mass total of elastomer, the balance consists of natural rubber ("NR").
• the rubber anchoring mixture additionally contains reinforcing fillers such as carbon black and a vulcanization system suitable for obtaining the desired rigidity.
• the circumferential reinforcing elements are in the examples presented brass plated metal cables. It is therefore necessary that the rubbery anchoring mixture has a high sulfur content and contains additives which promote adhesion with brass (for example metal salts of cobalt or nickel).
• a sulfur content of between 5 and 8% of the total mass of elastomer is used and a carbon black content of between 60 and 70% of the total mass of elastomer. N347 carbon black can be used preferentially.
• the four mixtures have satisfactory rigidity.
• the mixture 1 based on natural rubber only, has a completely insufficient resistance to static creep at high temperature. A rupture of the test pieces is observed after 30 minutes of testing. Its thermal stability is also unsatisfactory since the mixture has a very marked rate of reversion.
• Mixtures 3 and 4 pass the static creep and rheometry tests. Their creep resistance is quite correct and their thermal stability at high temperature too.
• the tires have shown a suitable suitability for mounting and dismounting operations, but only those comprising a rubber anchoring mixture corresponding to the formulations of mixtures 3 and 4 have shown sufficient endurance resistance of the anchoring of the carcass ply in the beads. Furthermore, the tires corresponding to mixtures 3 and 4 have undergone burst resistance tests and the maximum pressures measured have been of the order of 58 bars. They are also characterized by a rate of elongation of their development between the zero pressure and their operating pressure of 15 bars of the order of 1.5%. These tires have also successfully undergone takeoff tests similar to the standardized tests for the approval of aircraft tires.
• This manufacturing method has the advantage of greatly reducing or even eliminating the prestresses imposed on the reinforcements, particularly those oriented at 0 °, during the traditional phases of conformation.
• This embodiment also guarantees the absence of prestresses due to conformation in the vulcanization press.
• the choice of cables laid in a circumferential orientation in the zone of the bead to ensure the anchoring of the reinforcing elements of the carcass reinforcement makes it possible to obtain satisfactory manufacturing yields; in fact, the choice of these cables allows them to be hooked enough when laid bare enough that they will not come off or simply move before the cooking phase.
• the description of the figures has been limited to the case of tires in which the means for anchoring the reinforcing elements of the carcass reinforcement in each bead are circumferentially oriented cables axially bordering the circumferential alignments of said reinforcing elements of the carcass reinforcement.
• the carcass reinforcement comprises at least one layer of reinforcing elements having a turning area around at least one reinforcing element oriented circumferentially such as a bead wire.
• the invention should also not be understood as being limited to the case of mounted assemblies consisting in particular of a one-piece type wheel comprising a hollow base functionality; as explained above, the invention also relates to mounted assemblies consisting of a tire according to the invention and of a standard wheel for aircraft applications consisting of several parts.

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• 2004
  • 2004-01-15 CA CA002512840A patent/CA2512840A1/fr not_active Abandoned
  • 2004-01-15 EP EP11171183A patent/EP2384910A3/de not_active Withdrawn
  • 2004-01-15 JP JP2006500568A patent/JP5106846B2/ja not_active Expired - Fee Related
  • 2004-01-15 WO PCT/EP2004/000228 patent/WO2004065141A1/fr not_active Ceased
  • 2004-01-15 EP EP04702316A patent/EP1601541A1/de not_active Withdrawn
  • 2004-01-15 BR BRPI0406773-8B1A patent/BRPI0406773B1/pt not_active IP Right Cessation
• 2005
  • 2005-07-18 US US11/182,860 patent/US20050252593A1/en not_active Abandoned
• 2009
  • 2009-03-17 US US12/405,873 patent/US9027618B2/en not_active Expired - Fee Related

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