WO2016070030A1 - Pneu doté d'une surcouche de ceinture en mousse - Google Patents

Pneu doté d'une surcouche de ceinture en mousse Download PDF

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Publication number
WO2016070030A1
WO2016070030A1 PCT/US2015/058293 US2015058293W WO2016070030A1 WO 2016070030 A1 WO2016070030 A1 WO 2016070030A1 US 2015058293 W US2015058293 W US 2015058293W WO 2016070030 A1 WO2016070030 A1 WO 2016070030A1
Authority
WO
WIPO (PCT)
Prior art keywords
tire
belt
overlayer
foamed
tread
Prior art date
Application number
PCT/US2015/058293
Other languages
English (en)
Inventor
Francois Hottebart
Olivier Piffard
Xavier Saintigny
Original Assignee
Compagnie Generale Des Etablissements Michelin
Michelin Recherche Et Technique 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 Compagnie Generale Des Etablissements Michelin, Michelin Recherche Et Technique S.A. filed Critical Compagnie Generale Des Etablissements Michelin
Publication of WO2016070030A1 publication Critical patent/WO2016070030A1/fr

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
    • B60C9/00—Reinforcements or ply arrangement of pneumatic tyres
    • B60C9/18—Structure or arrangement of belts or breakers, crown-reinforcing or cushioning layers
    • 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
    • B60C11/00—Tyre tread bands; Tread patterns; Anti-skid inserts
    • B60C11/0041—Tyre tread bands; Tread patterns; Anti-skid inserts comprising different tread rubber layers
    • B60C11/005—Tyre tread bands; Tread patterns; Anti-skid inserts comprising different tread rubber layers with cap and base layers
    • 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
    • B60C9/18—Structure or arrangement of belts or breakers, crown-reinforcing or cushioning layers
    • B60C2009/1828—Structure or arrangement of belts or breakers, crown-reinforcing or cushioning layers characterised by special physical properties of the belt 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
    • B60C9/00—Reinforcements or ply arrangement of pneumatic tyres
    • B60C9/18—Structure or arrangement of belts or breakers, crown-reinforcing or cushioning layers
    • B60C2009/1878—Structure or arrangement of belts or breakers, crown-reinforcing or cushioning layers with flat cushions or shear layers between the carcass and the belt

Definitions

  • This invention relates generally to tires and more particularly to tires having a foamed undertread.
  • the tire tread is of course known to be the road-contacting portion of a tire that extends circumferentially around the tire. It is designed to provide the handling characteristics required by the vehicle, e.g., traction, dry braking, wet braking, cornering and so forth - all being provided preferably with a minimum amount of noise being generated and at a low rolling resistance.
  • Treads include tread elements that are the structural features of the tread that contact the ground. Such structural features may be of any size or shape, examples of which include tread blocks and tread ribs. Tread blocks have a perimeter defined by one or more grooves that create an isolated structure in the tread while a rib runs substantially in the longitudinal (circumferential) direction and is not interrupted by any grooves that run in the substantially lateral direction.
  • treads may be formed from only one rubber composition or, for example, in two layers of differing rubber compositions, e.g., a cap and base construction.
  • a cap and base construction the cap portion of the tread is made of one rubber composition that is designed for contact with the road.
  • the cap is supported on the base portion of the tread, the base portion made of a different rubber composition.
  • tires for a motor vehicle and the tires may be pneumatic tires or in other embodiments they may be non- pneumatic tires.
  • the tires comprise several tire components including a tread having a radially outer part intended to come into contact with a road surface, two inextensible beads, two sidewalls connecting the two inextensible beads to the tread, a carcass reinforcement anchored in the beads and extending into the sidewalls, and a crown supporting the tread and having a circumferentially arranged belt package positioned radially outward from the carcass reinforcement.
  • such tires may further include a foamed belt overlayer covering a majority of a radially outer surface of the belt package.
  • a foamed belt overlayer covering a majority of a radially outer surface of the belt package.
  • Such overlayer is formed of elastomeric foam.
  • the elastomeric foam is open cell foam.
  • FIG. 1 is a schematic depiction of the changes that an exemplary tread block undergoes as it passes through a contact patch of a tire.
  • FIG. 2 is a cross sectional view of an exemplary tire showing a foamed belt overlayer positioned between the belt and the tread.
  • FIG. 3 is a partial cross sectional view of an exemplary tire showing a foamed belt overlayer positioned between the belt and the tread.
  • Particular embodiments of the present invention include tires having a foamed belt overlayer covering a majority of the outer radial surface of the tire's belt package to provide improved wear properties of the tire tread.
  • the improved wear is achieved by the action of the foamed belt overlayer compacting when the tire enters the contact patch and then recovering its initial shape upon exiting the contact patch as explained below.
  • the tire contact patch is known to be that portion of the tire that is in actual contact with the road surface, i.e., that portion of the tire tread that touches the road surface. As the tire rotates, the tire contact patch is continuously changing to a different portion of the tire with that portion of the tire entering the contact patch being the leading edge of the contact patch and that portion of the tire exiting the contact patch being the trailing edge of the contact patch.
  • FIG. 1 is a schematic depiction of the changes that an exemplary tread block undergoes as it passes through the contact patch.
  • the tread block 28 of a tread 27 Before entering the contact patch at the leading edge (L), the tread block 28 of a tread 27 is not deformed at all since it is not being subjected to any shear force. It can be seen, however, that after the tread block has passed the leading edge (L) and is in the contact patch, the tread block 28 becomes deformed in the direction of travel (x) as a result of the shear applied to the tread block through its interaction with the road surface. It is this interaction that provides the acceleration or maintains the velocity as required by the vehicle on which the tire is mounted.
  • the pressure in the vertical (z) or radial direction is the result of forces between the tire and road surface that provide support for the vehicle and these forces are transmitted through the tread to the tire's belt package.
  • the inventors have provided the foamed belt overlayer of the belt package.
  • the foamed belt overlayer of the belt package is compacted providing a high level of rigidity between the tread block contacting the ground and tire belt package.
  • the rigidity between the tread block contacting the ground and the belt package is reduced or decoupled, thereby reducing the forces acting on the tread block in the sliding zone and reducing the tread wear.
  • FIG. 2 is a cross sectional view of an exemplary tire showing a foamed belt overlayer positioned between the belt and the tread.
  • the tire shown is merely an example of a tire having a foamed belt overlayer positioned between the belt and the tread and this illustration is not meant to limit the invention only to tires similar to the one pictured. Indeed there are many tire architectures that would benefit from the wear reducing foamed overlayer that is disclosed herein including, for example, non-pneumatic tires.
  • the tire 20 includes a crown section 21, a bead section 23 and a sidewall section 25.
  • the tire has a tread 27 for contacting the road surface that includes tread blocks 28.
  • the tread 27 is supported by the crown section 21 that is positioned radially-inward of the tread 27, the crown 21 having a belt package 30 to stiffen the casing and to provide improved wear and handling response.
  • the belt package 30 may include one or more layers of cords, typically steel cords, embedded in a thin layer of rubber and typically arranged circumferentially around the tire.
  • the crown section 21 also includes the foamed belt overlayer 32 that covers a majority of the radially outer surface of the belt package 30.
  • the pair of bead sections 23 are arranged to face each other in the tire width or axial direction.
  • the bead section 23 includes the bead 34 which is an inextensible bead core that anchors the plies and locks the tire onto a wheel assembly.
  • the pneumatic tire 20 further includes a carcass ply 38.
  • the carcass ply 38 extends between the beads 34 of the tire 20 and terminates in a pair of carcass layer ends 42.
  • the carcass ply 38 therefore extends from one bead 34 through one sidewall section 25, through the crown section 21 and through the other sidewall section 25 to the other bead 34.
  • Each carcass layer end 42 is formed by wrapping the carcass ply 38 around one of the beads 34 and then terminating it.
  • the carcass ply 38 may be constructed from a plurality of mutually parallel textile or metal cords embedded in an elastomeric matrix, such as a thin layer of a rubber composition.
  • the carcass ply 38 is typically formed using a calendaring process wherein the cords are laid parallel to each other and encased in the elastomeric matrix.
  • the carcass ply 38 is then arranged in a manner such that the cords are typically oriented in a radial direction along the sidewalls 44 of the tire 20. More specifically, along the sidewalls 44 of the tire 10, the cords of the carcass ply 38 are substantially perpendicular to the axis of rotation of tire.
  • FIG. 3 is a partial cross sectional view of an exemplary tire showing a foamed belt overlayer positioned between the belt and the tread.
  • the foamed belt overlayer 32 may be typically, for example, between 1 mm and 10 mm thick or alternatively, in other embodiments, may be between 1.5 mm and 5 mm thick, between 2 mm and 10 mm, between 2 mm and 5 mm thick or between 2 mm and 3 mm thick.
  • the thickness of the foamed belt overlayer begins to exceed a maximum for a given tire, the handling characteristics of the tire will become affected and if the thickness is less than a minimum for a given tire, the desired effect of reducing wear by decoupling the forces will diminish.
  • the foamed belt overlayer 32 be positioned on the radially outer surface 52 of the belt package 30 so that the wear forces can be decoupled as quickly as possible.
  • a nylon cord reinforced rubber layer (not shown) may be positioned between the belt package 30 and the foamed belt overlayer 32 as is known to those skilled in the art to provide stability to the belt package 30.
  • other layers of materials may not be placed between the foamed belt overlayer and the radially outer surface of the belt package.
  • the belt package has a radially outer surface 52 that includes two lateral edge sections and a central section.
  • the lateral edge sections extend from the lateral edge of the belt package towards the other lateral edge.
  • the lateral direction is the axial direction and the radial direction is perpendicular to the axial or lateral direction.
  • the central section Between the two lateral edge sections is the central section. If, for example, the central section was 80 percent of the radially outer surface 52 of the belt package, then the lateral sections would include 20 percent of the radially outer surface 52. Likewise, if the central section was 90 percent of the radially outer surface 52 of the belt package, then the lateral sections would be 10 percent of the radially outer surface 52. If the central section was 100 percent of the radially outer surface 52 of the belt package, then the lateral sections would be nonexistent. While in particular embodiments the lateral sections would be of equal size, in other embodiments that is not necessary.
  • the foamed belt overlayer is made of elastomeric foam such as natural rubber, a synthetic rubber, a polyurethane elastomer and others and mixtures of such elastomers.
  • elastomeric foam such as natural rubber, a synthetic rubber, a polyurethane elastomer and others and mixtures of such elastomers.
  • mixtures of natural rubber with one or more synthetic rubbers and mixtures of one or more different synthetic rubbers are useful when foamed.
  • synthetic rubber include EPDM, polyisoprene, polybutadiene and styrene-butadiene rubbers.
  • the foamed elastomer is a cellular material that contains cells, either open, closed or both, that are dispersed throughout the material. Closed cell foams are those with cells that are totally enclosed by their walls and are not interconnected with any other cells. Open cell foams are those with cells not totally enclosed by their walls and open to the surface, either directly or indirectly by interconnecting with other cells.
  • the foam should be a quick recovery foam wherein the foam rapidly recovers its shape as the compressive forces are removed. While open or closed cell foams may be suitable for given embodiments of the tires disclosed herein, typically foams that are open cell or predominately open cell foams are more resilient. In particular embodiments, the foam material is an open cell foam or alternatively one having at least a majority (predominately) or having at least 80% of the total number of cells as open cells.
  • the compression deflection property of the foam is a characterization of the firmness of the foam and is often expressed as pounds per square inch at a given percentage of deflection. Such measurements are made compliance with the ASTM Standard Specification of Flexible Cellular Materials - Sponge or Expanded Rubber designated as ASTM D1056-14. Suitable foams may have a compression deflection at 25 % of between 1.5 bar and 5 bar or alternatively between 2 bar and 4 bar or between 2 bar and 3 bar. It is desirable in particular embodiments to have a foam that is firmer rather than too soft so that upon compression in the contact patch, the foam will provide a high level of rigidity between the tread block contacting the ground and tire belt package.
  • Suitable foams may be purchased as sheet and applied to the outer radial surface of the belt package.
  • the foamed sheets may be bonded to the out surface by a suitable adhesive, an example being a CHEMLOCK adhesive.
  • CHEMLOCK adhesives are available from Lord Corporation in Erie, PA.
  • CHEMLOCK adhesives are available for bonding rubber to rubber and for bonding rubber to materials such as polyurethane.
  • the tire manufacturing process may include assembling various components of the tire on a building drum.
  • the assembled components of the tire carcass remain on the drum while in a two- stage process, the carcass is removed from the drum and moved to a second stage finishing drum.
  • the carcass is inflated to receive a finished tread band to produce the finished green tire.
  • the green tire is then placed in a mold and vulcanized to produce the final tire product.
  • a green tire is a term used to denote one that has not been vulcanized.
  • the foamed sheet can be added to the top surface of the belt package during the assembly process of the tire on the building drum.
  • the foamed sheet can be cut to the proper size and laid on top of the outer surface, bonding to the surface using an adhesive as suggested above.
  • Useful foams may be obtained, for example, from McMaster-Carr having offices in Elmhurst, IL and from Rogers Corporation with offices in Woodstock CT.
  • PORON polyurethane foams are useful and are recognized as a high-performance foam that has a quick recovery after compression and is of an open cell construction.
  • An example of a useful foam is PORON 4701-50 having a compression deflection at 25% of between about 2 bar and about 4 bar and available in sheets that are about 1 mm thick.
  • a PORON product available from McMaster-Carr has a thickness of about 3 mm and a compression deflection at 25% of 2.5 bar. Such foams are available in a wide range of compression deflection properties and thickness.
  • elastomeric foams are those that can be included in a tire, such as those made from the exemplary elastomeric materials disclosed above and that have a quick recovery after compression, such as may be found in open cell foams or, in particular embodiments, those that are predominately open celled foams.
  • the foams may contain other materials as known to those skilled in the art including, for example, antidegradants, colorants, plasticizers, activators, reinforcing materials such as carbon black and/or silica, vulcanizing agents and so forth. So that the foam is capable of maintaining the rigidity between the tread block contacting the ground and the belt package, useful foams include those having the compression deflection force properties as disclosed above.

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

Abstract

L'invention concerne un pneumatique (27) comportant une bande de roulement présentant une partie radialement externe destinée à entrer en contact avec une surface de roulement, deux talons inextensibles (34), deux flancs (25) raccordant les deux talons inextensibles à la bande de roulement, une armature de carcasse (38) ancrée dans les talons et s'étendant à l'intérieur des flancs, et une couronne supportant la bande de roulement et présentant un ensemble ceinture (30) agencé de façon circonférentielle positionné radialement vers l'extérieur depuis l'armature de carcasse,,ledit pneu pouvant comprendre en outre une surcouche de ceinture (32) en mousse recouvrant la majorité d'une surface radialement externe de l'ensemble ceinture (30) et. formée de mousse élastomère, laquelle peut être une mousse à alvéoles ouverts.
PCT/US2015/058293 2014-10-31 2015-10-30 Pneu doté d'une surcouche de ceinture en mousse WO2016070030A1 (fr)

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
US201462073725P 2014-10-31 2014-10-31
US62/073,725 2014-10-31

Publications (1)

Publication Number Publication Date
WO2016070030A1 true WO2016070030A1 (fr) 2016-05-06

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ID=54477399

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PCT/US2015/058293 WO2016070030A1 (fr) 2014-10-31 2015-10-30 Pneu doté d'une surcouche de ceinture en mousse

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Citations (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
EP0576130A1 (fr) * 1992-06-24 1993-12-29 Bridgestone Corporation Bandages pneumatiques
JPH06247106A (ja) * 1993-02-22 1994-09-06 Bridgestone Corp 空気入りタイヤ
JPH0867110A (ja) * 1994-08-30 1996-03-12 Bridgestone Corp 空気入りラジアルタイヤ
US6216757B1 (en) * 1991-11-18 2001-04-17 Bridgestone Corporation Low noise level tire

Patent Citations (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US6216757B1 (en) * 1991-11-18 2001-04-17 Bridgestone Corporation Low noise level tire
EP0576130A1 (fr) * 1992-06-24 1993-12-29 Bridgestone Corporation Bandages pneumatiques
JPH06247106A (ja) * 1993-02-22 1994-09-06 Bridgestone Corp 空気入りタイヤ
JPH0867110A (ja) * 1994-08-30 1996-03-12 Bridgestone Corp 空気入りラジアルタイヤ

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