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WO2002030686A1 - Pneumatique à contour intérieur optimisé - Google Patents

Pneumatique à contour intérieur optimisé Download PDF

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Publication number
WO2002030686A1
WO2002030686A1 PCT/EP2001/011569 EP0111569W WO0230686A1 WO 2002030686 A1 WO2002030686 A1 WO 2002030686A1 EP 0111569 W EP0111569 W EP 0111569W WO 0230686 A1 WO0230686 A1 WO 0230686A1
Authority
WO
WIPO (PCT)
Prior art keywords
bead
tire
tire according
carcass
curvature
Prior art date
Legal status (The legal status 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 status listed.)
Ceased
Application number
PCT/EP2001/011569
Other languages
English (en)
Inventor
Roger C. Cottrell
Walter L. Willard, Jr.
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
Michelin Recherche et Technique SA Switzerland
Societe de Technologie Michelin SAS
Original Assignee
Michelin Recherche et Technique SA Switzerland
Societe de Technologie Michelin SAS
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 Michelin Recherche et Technique SA Switzerland, Societe de Technologie Michelin SAS filed Critical Michelin Recherche et Technique SA Switzerland
Priority to AU2002223600A priority Critical patent/AU2002223600A1/en
Publication of WO2002030686A1 publication Critical patent/WO2002030686A1/fr
Anticipated expiration legal-status Critical
Ceased legal-status Critical Current

Links

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
    • B60C3/00—Tyres characterised by the transverse section
    • B60C3/04—Tyres characterised by the transverse section characterised by the relative dimensions of the section, e.g. low profile
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B60—VEHICLES IN GENERAL
    • B60C—VEHICLE TYRES; TYRE INFLATION; TYRE CHANGING; CONNECTING VALVES TO INFLATABLE ELASTIC BODIES IN GENERAL; DEVICES OR ARRANGEMENTS RELATED TO TYRES
    • B60C13/00—Tyre sidewalls; Protecting, decorating, marking, or the like, thereof
    • 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
    • B60C13/00—Tyre sidewalls; Protecting, decorating, marking, or the like, thereof
    • B60C13/003—Tyre sidewalls; Protecting, decorating, marking, or the like, thereof characterised by sidewall curvature
    • B60C13/004—Tyre sidewalls; Protecting, decorating, marking, or the like, thereof characterised by sidewall curvature of the internal side of the tyre
    • 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
    • B60C17/00—Tyres characterised by means enabling restricted operation in damaged or deflated condition; Accessories therefor
    • B60C17/0009—Tyres characterised by means enabling restricted operation in damaged or deflated condition; Accessories therefor comprising sidewall rubber inserts, e.g. crescent shaped inserts

Definitions

  • the invention relates to a tire, more specifically to a pneumatic tire capable of continued mobility in a deflated condition.
  • tires which normally operate in an inflated condition but which also permit a limited operation in a deflated condition.
  • These tires constructions are generally formed of one or more generally radial carcasses which are turned up around one or more bead wires arranged in each bead.
  • sidewalls which are reinforced and thickened by interposing additional rubber layers between the carcasses or between the carcasses and the tire inner liner.
  • the runflat tires have an inner contour of their sidewall portions with a concave curvature, i. e. a curvature the center of which is disposed towards the inside of the tire cavity.
  • FR 2 344 413 presents a runflat tire with the sidewalls reinforced by inserts made of foam. These inserts, in the embodiment of figure 1 , are placed radially under the sides of the belt of the summit of the tire in order to support it when deflated.
  • the inner side of this tire has a pronounced convex curvature.
  • Inflated and deflated performance also depends on the carcass structural arrangement, materials and on the carcass path.
  • the carcass path is such that, in operation, at least a portion of the carcass may be placed in a compressive stress due to its position at the axially outward side of the bead/sidewall structure.
  • Tensile-compressive cyclic stress may affect the product durability. For instance tires having carcasses turned up around bead wires necessarily have a discontinuity at the radially uppermost extent of the turned up portion of one or more of the carcasses.
  • the invention provides a tire comprising a carcass structure anchored in each side of the tire in a bead, each bead having a base which is intended to be mounted on the tire's design mounting rim, each bead being extended radially upward by a sidewall portion, a reinforced summit, the sidewall portions joining said summit, said tire having an inner and an outer contour, wherein the sidewall inner contour comprises a convex portion with a radius of curvature superior to H/2, H being the Section Height of the tire.
  • This convex portion i. e. that this portion has a center of curvature placed outwardly of the tire cavity, has the advantage to provide an even distribution of the stress-strain cycles in the rubber mixes of the sidewall during deflated operation. As a consequence, this gives a better 0-psi durability.
  • the height of this convex portion is comprised between 0,3 and 0,5 H.
  • This convex portion may have a radius of curvature substantially infinite.
  • the convex portion is adjacent a concave portion placed radially inwardly with a radius of curvature between 0,2 and 0,3 H.
  • the sidewall inner contour may further comprise a substantially linear portion.
  • the sidewall inner contour may comprises a first concave zone with a first radius of curvature, a convex portion with a second radius of curvature, a second concave zone with a third radius of curvature and a substantially linear portion.
  • the first radius of curvature is between 0,15 H and 0,25 H and is inferior to the third radius of curvature.
  • the third radius of curvature may be between 0,2 H and 0,3 H.
  • the tire of the invention further comprises a bead with an anchoring zone for anchoring of the carcass structure wherein the carcass structure has at least one circumferential alignment of cords in this anchoring zone, which progressively divides in the sidewall portion in at least two circumferential alignments of cords.
  • This carcass structure is very flexible and allows placing the carcass cords where they are most useful.
  • the density of cords of the axially exterior carcass layer is preferably superior to the density of cords of the axially interior carcass layer.
  • a runflat insert is disposed between these two carcass circumferential cord alignments and this runflat insert is in direct contact with the cords of the two circumferential alignments.
  • the direct contact between the runflat insert and the cords of the two adjacent carcass layers gives an excellent homogeneity of the mechanical properties of the structure, which drives to a better durability in 0-psi performance.
  • the construction is also simplified due to the least number of rubber mixes necessary for its building.
  • the carcass structure of the tire of the invention comprises only one circumferential alignments of cords in the summit portion of the tire.
  • the anchoring zone is provided with at least one first bead reinforcement, at least partially bordering said carcass structure and a high modulus rubber mix cooperating with said bead reinforcement and with said carcass structure for anchoring said a carcass structure in the bead.
  • the bead reinforcement advantageously includes at least one substantially circumferentially oriented cord laterally bordering the carcass structure on at least one side.
  • Such an arrangement provides the possibility of taking up the tension developed in the carcass during inflated or deflated use of the tire.
  • the carcass structure comprises only one circumferential alignment in the summit portion of the tire. This has the advantage of limiting the thickness of the summit of the tire. Such a tire has reduced weight and rolling resistance and improved inflated and deflated performances.
  • Figure 1 illustrates the sidewall and bead portion of a runflat tire according to the invention, taken along a meridian plane through the axis of rotation;
  • Figure 2 illustrates the sidewall and bead portion of a second embodiment of a runflat tire according to the invention, taken along a meridian plane through the axis of rotation, with two carcass layers in the bead and three in the sidewall;
  • Figure 3 is an enlarged perspective view of the bead portion of a runflat tire corresponding to the second embodiment of the invention showing the common circumferential disposition of the first and second carcass layers;
  • Figure 4 illustrates the evolution of the sidewall inner contour from a prior art tire to the tire of the invention.
  • Equatorial plane means the plane perpendicular to the tire's axis of rotation and passing through the center of its tread.
  • Ring and radially mean directions radially toward or away the axis of rotation of the tire.
  • “Section Height (H)” means the radial distance from the nominal rim diameter (D) to the outer diameter of the tire at its equatorial plan (EP).
  • the tire 1 of the invention comprises a bead 3 provided with a seat 6, specially adapted to fit on the tire's mounting rim 2.
  • the bead 3 extends substantially radially to the sidewall 7.
  • the sidewall 7 joins the tire summit 8.
  • the tire summit comprises a usual belt structure 9.
  • the tire comprises a carcass structure 5, extending from bead to bead or leaving a gap between two half structures, for instance in the substantially median portion of the summit.
  • the radially inwardmost extent of the carcass structure 5 terminates in an anchoring zone 4 of the bead 3.
  • the carcass structure is not turned up around bead cores or other bead reinforcement. That is to say, each axial coordinate defining the profile of the carcass structure has a unique radial position for each radial position less than that of the tire equator.
  • the carcass structure is anchored in the bead portion by a bead reinforcement.
  • a preferred embodiment of such a reinforcement comprises a cord arrangement 10 provided with at least one substantially circumferentially oriented cord 41 laterally bordering the carcass structure on at least one side.
  • "anchored" in the bead portion means that the arrangement resists the tension developed in the carcass structure during inflated or deflated use of the tire by the adherence of the carcass reinforcing structure laterally with the cords 41 and 42 rather than being wound around a traditional bead core.
  • the mechanical properties of the anchoring zone 4 are optimized in using a bead filler having a very high elastic modulus.
  • typical values may be within the following range: the shore A hardness may be equal or greater than 95 and the modulus at 10 % greater than 60 MPa.
  • the carcass structure 5 of the tire 1 has more than one carcass layer within some portion of the tire.
  • the carcass structure 5 comprises one circumferential alignment of cords in the summit 8.
  • the carcass structure 5 is divided in two circumferential alignments of radial cords 51 and 52. These two circumferential alignments of cords progressively move axially away from each other.
  • the two circumferential alignments of cords 51 and 52 join and give a common circumferential alignment of cords 5. Accordingly, in the bead 1 , there is only one circumferential alignment of cords.
  • This carcass structure is very flexible and allows placing the carcass cords where they are most useful.
  • the density of cords of carcass layer 52 is advantageously superior to the carcass density of cords of the carcass layers 51.
  • the cords of the outer carcass layer are subjected to high-tension stress-strain cycles in inflated and deflated operation. These cords are well designed to support these high-tension cycles and the number of cords is defined accordingly.
  • the cords of the inner carcass layer are subjected in deflated operation to stress-strain cycles with compression. In this case, it is the rubber mixes, which are well designed to support these compression stresses.
  • the number of cords needs not to be high. It allows also a limited thickness of the carcass structure in the summit and an appropriate anchoring in the bead portion.
  • runflat inserts are placed in the sidewall between the carcass layers 51-52 - insert 92 and also between the carcass structure 5 and the inner side of the tire - insert 91 - in order to have a good 0-psi performance.
  • these runflat inserts are in direct contact of the cords of the adjacent carcass layers. This means that the rubber mixes constituting the runflat inserts are in intimate contact with at least part of the outer circumference of the cord, and that during the building of the tire, no usual cushion rubber mix of low modulus of elasticity has been used. Accordingly, the sidewall structure has a better durability in deflated operation.
  • the tire comprises an outer contour 12 and an inner contour 13.
  • the inner contour 13 comprises, from the summit side towards the bead, a first concave zone 14 having a first radius of curvature R1 , a convex portion 15 having a high radius of curvature R2, a second concave zone 16 having a third radius of curvature R3 and a substantially linear portion 17.
  • This substantially linear portion 17 joins the bead inner contour.
  • the convex portion 15 has a curvature with a radius R2 superior to half the Section Height of the tire:
  • the radius of curvature R1 of the first concave zone 14 is preferably between 15 % and 25 % of the Section Height H of the tire.
  • R3 is between 20 % to 30 % of the Section Height H of the tire 1.
  • the length L1 of the convex portion of the inner contour of the sidewall, measured in a radial direction, is between 30 % and 50 % of the Section Height H of the tire 1. Accordingly, the length L2 of the substantially linear portion of the sidewall inner contour may vary with the type of the tire considered.
  • substantially linear portion 17 and the carcass alignment of cords in the bead are substantially parallel. They are also parallel to the two windings of circumferentially oriented cords 41 and 42 and to the anchoring zone as a whole. This results in a very stiff, compact and resistant bead structure, the durability of which is excellent, notably in deflated operation.
  • the previous dimensions are calculated with the tire 1 being mounted on its design rim 2, inflated but unloaded.
  • Such an inner contour of sidewall of the tire 1 has the advantage to provide to the rubber mixes constituting the sidewall a more even distribution of the stress-strain cycles during deflated operation. As a consequence, the durability performance of the tire in deflated operation is improved.
  • Figure 2 illustrates a second embodiment of the invention in which the convex portion 25 has a very high radius of curvature, substantially infinite.
  • the carcass structure 5 comprises one circumferential alignment of cords in the summit 5.
  • the carcass structure 5 is divided in three circumferential alignments of radial cords 511, 512 and 52.
  • the density of cords of carcass layer 52 is advantageously superior to the carcass density of cords of the carcass layers 511 and 512.
  • This structure allows a limited thickness of the carcass structure in the summit and an appropriate anchoring in the bead portion.
  • the anchoring of the carcass structure 5 is achieved by three windings 41 , 42, 43 of circumferential oriented cords, which axially border the two circumferential alignments of cords 51 and 52 of the carcass structure with the interposition as in the previous embodiment of figure 1 of a high modulus rubber layer.
  • another runflat insert 93 is placed in the sidewall between the carcass layers 512 and 52 in order to improve the 0-psi performance.
  • the runflat inserts are in direct contact of the cords of the adjacent carcass layers.
  • Figure 3 illustrates the structure of the radial and circumferential cords in the bead 3 of the second embodiment.
  • the anchoring zone axially outward, we have the first circumferentially oriented winding 41 , the first carcass circumferential alignment 51 , the second circumferentially oriented winding 42, the second carcass circumferential alignment 52 and the third circumferentially oriented winding 43.
  • the first carcass circumferential alignment 51 is divided in two carcass circumferential alignments 511 and 512.
  • the rubber mixes are not represented in this figure for clarity. All these cords are embedded, at least in the anchoring zone, by a high modulus rubber mix. Preferably, this rubber mix has a shore A hardness over 80.
  • All the carcass cords presented in figure 3 are placed with a circumferentially shifted position, which allows them to form one sole alignment in the summit portion of the tire. This allows minimizing the thickness of the summit portion.
  • the cords 41 , 42 and 43 are advantageously made of steel. Monofilament or cable structure cords may be used. Textiles type cords, such as aramid, nylon, PET, PEN, or hybrids such as aramid/nylon, etc., may also be used alone or in combination with metallic cords.
  • the carcass structure can also present one circumferential alignment of cords in the summit and the bead, which divide in three in the sidewall.
  • Figure 4 illustrates the evolution of the sidewall inner contour from a prior art tire to the tire of the invention.
  • the broken line 20 gives the usual sidewall inner contour. This contour is concave.
  • the line 21 gives the optimized contour of the inventive tire with the first transition region 14 (R1), the convex region 15 (R2), the second transition region 16 (R3) and the linear portion 17 adjacent the bead.
  • the optimized contour tire a P 225/60 R16 MXV4 ZP, has a more efficient use of its mass.
  • the amelioration of the durability in deflated condition is very sensitive.

Landscapes

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

Abstract

Cette invention a trait à un pneumatique comportant une structure de carcasse ancrée, de chaque côté du pneumatique, à un talon, chaque talon possédant une assise conçue pour être montée sur la jante de montage dudit pneumatique, laquelle assise étant prolongée radialement et verticalement par une partie latérale. Ce pneumatique comporte également une partie sommitale renforcée à laquelle viennent se joindre les parties latérales. Ce pneumatique possède un contour intérieur et un contour extérieur, le contour latéral intérieur comportant une partie convexe dont le rayon de courbure est supérieur à H/2, H représentant la hauteur de section du pneumatique.
PCT/EP2001/011569 2000-10-10 2001-10-08 Pneumatique à contour intérieur optimisé Ceased WO2002030686A1 (fr)

Priority Applications (1)

Application Number Priority Date Filing Date Title
AU2002223600A AU2002223600A1 (en) 2000-10-10 2001-10-08 Tire with optimized interior contour

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
US0027876 2000-10-10
USPCT/US00/27876 2000-10-10

Publications (1)

Publication Number Publication Date
WO2002030686A1 true WO2002030686A1 (fr) 2002-04-18

Family

ID=21741864

Family Applications (1)

Application Number Title Priority Date Filing Date
PCT/EP2001/011569 Ceased WO2002030686A1 (fr) 2000-10-10 2001-10-08 Pneumatique à contour intérieur optimisé

Country Status (2)

Country Link
AU (1) AU2002223600A1 (fr)
WO (1) WO2002030686A1 (fr)

Citations (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3994329A (en) * 1974-05-24 1976-11-30 Pneumatiques, Caoutchouc Manufacture Et Plastiques Kleber-Colombes Safety tire for vehicles
FR2344413A2 (fr) * 1976-03-15 1977-10-14 Kleber Colombes Pneumatique de securite pour vehicule
GB1507082A (en) * 1974-07-02 1978-04-12 Kleber Colombes Pneumatic tyres

Patent Citations (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3994329A (en) * 1974-05-24 1976-11-30 Pneumatiques, Caoutchouc Manufacture Et Plastiques Kleber-Colombes Safety tire for vehicles
GB1507082A (en) * 1974-07-02 1978-04-12 Kleber Colombes Pneumatic tyres
FR2344413A2 (fr) * 1976-03-15 1977-10-14 Kleber Colombes Pneumatique de securite pour vehicule

Also Published As

Publication number Publication date
AU2002223600A1 (en) 2002-04-22

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