EP1047564A1 - Radial medium truck tire with multifilament top belt - Google Patents
Radial medium truck tire with multifilament top beltInfo
- Publication number
- EP1047564A1 EP1047564A1 EP97948392A EP97948392A EP1047564A1 EP 1047564 A1 EP1047564 A1 EP 1047564A1 EP 97948392 A EP97948392 A EP 97948392A EP 97948392 A EP97948392 A EP 97948392A EP 1047564 A1 EP1047564 A1 EP 1047564A1
- Authority
- EP
- European Patent Office
- Prior art keywords
- organic
- filaments
- belt
- ply
- tire
- 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.)
- Withdrawn
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
- B60C9/0042—Reinforcements made of synthetic materials
-
- 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
- B60C9/20—Structure or arrangement of belts or breakers, crown-reinforcing or cushioning layers built-up from rubberised plies each having all cords arranged substantially parallel
- B60C9/2003—Structure or arrangement of belts or breakers, crown-reinforcing or cushioning layers built-up from rubberised plies each having all cords arranged substantially parallel characterised by the materials of the belt cords
- B60C9/2009—Structure or arrangement of belts or breakers, crown-reinforcing or cushioning layers built-up from rubberised plies each having all cords arranged substantially parallel characterised by the materials of the belt cords comprising plies of different materials
Definitions
- the present invention relates to radial truck tires, preferably radial medium truck (RMT) pneumatic tires.
- the treads of RMT tires are .subject to puncture from stones .and other sharp objects in the road surface.
- the puncture is not deep enough to penetrate the belt package and destroy the tire, it is deep enough to expose the steel reinforcement cords of the belt package to water and air, and such exposure can cause the belt package to corrode. This problem is aggravated when tires are used in mixed service, i.e., partially on paved surfaces and partially on non-paved surfaces.
- the present invention also relates to preventing defects known as blows or blisters which are caused while curing the tire by the presence of air or other gases within the body of the tire being cured.
- defects can involve local separations, i.e., between the rubber and one or more of the reinforcement cords which make up the reinforcing ply of a pneumatic tire, between two rubber components, or within one rubber component.
- Air can become trapped in or between the layers of materials which are superimposed on one another in the course of building the tire, or can in some instances enter into the tire during a time lapse while building the tire, or can in some instances enter into the tire during the time lapse between the building of the tire and the placing of the tire into a curing mold.
- tire reinforcement cords contain passages extending generally throughout the length of the cord, lying between and bounded by the filaments which make up the cords, and that air or other gases can travel along such passages. It has been observed that the treatment of tire reinforcement cords, such as stretching heated cords of continuous filament materials, such as polyester and polyamide, tends to significantly reduce the cross sectional area of the interfilamentary passages. Stretching of heated cords can also result in the reduction of the cross sectional area of the individual filaments and the compacting of the filaments into a closer relationship one to another.
- RMT radial medium radial truck
- An object of the present invention is to provide an improved RMT tire with a top protective layer made of polyamide multi-filaments.
- Still another object of the present invention is to provide an improved RMT tire with a protective layer made of polyamide multi-filaments that have a low material stiffness, that are corrosion free, have a strong adhesion to rubber.
- an improved pneumatic radial medium truck tire of the invention comprises at least one pair of parallel annular beads, at least one carcass ply wrapped around the beads, a plurality of belts or breakers disposed over the carcass ply in a crown area of the tire, tread disposed over the belts or breakers, and sidewalls disposed between the tread and the beads.
- the majority of the belts or breakers in the tire are reinforced with steel filaments or cords.
- the top belt or breaker as well as any remaining belts or breakers are reinforcing cords comprised of multi-filaments constructed of twisted strands of an organic polymer.
- the organic multi-filaments comprise strands of yarn twisted together into a generally circular cross section.
- the organic multi-filaments are formed of about 420 dTex x 2 strands to about 3300 dTex x 3 strands.
- the multi-filament constructed from 420 dTex x 2 ⁇ strands twisted to between about 3 to about 20 turns per inch (about 1.2 to about 7.9 turns per centimeter) is smaller then that formed of 3300 dTex x 3 strands twisted to between about 3 to about 7 turns per inch (about 1.2 to about 2.8 turns per centimeter).
- the end count of the .smaller 2 strand multi-filament is between about 10 to about 50 strands per inch (about 3.9 to about 19.7 strands per centimeter) while the end count of the larger multi-filament is between about 5 to about 17 strands per inch (about 2.0 to about 6.7 strands per centimeter).
- the multi- filament constructed from 2100 d Tex x 3 strands twisted to between about 3 to about 9 turns per inch (about 1.2 to about 3.5 turns per centimeter) are used with an end count of between about 7 to about 22 strands per inch (about 2.8 to about 8.5 str-and per centimeter).
- the strands of the multi-filament have a tenacity of at least 35 cN/Tex, an initial modulus of at least 250 cN/Tex, an elongation at break of about 2 to about 40%, and a shrinkage of about 0.1 to about 10%.
- the top reinforcement ply or breaker is a polyamide multi-filament, reinforced ply wherein the reinforcement cords have an angle of 0° to 35° with respect to the EP of the tire.
- the overlay/top breaker ply extends beyond the edges of the other breakers, and the direction of the reinforcing cords are maintained at the same direction as the steel reinforcement cords in the breaker ply next radially below, or are at opposite directions which cross the steel reinforcement cords.
- the top layer multi-filament reinforcement functions as gas absorbing reinforcing cords embedded in rubber or rubber-like material.
- Fig. 1 is a cross-sectional view of a tire according to one embodiment of the invention taken in a plane that contains the axis of rotation of the tire;
- Fig. 2 illustrates a portion of a reinforcing ply constructed of multi-filament strands
- Fig. 3 is .an enlarged cross- sectional view of one embodiment of a multi-filament cable suitable for use in the present invention.
- Fig. 4 is an enlarged cross- sectional view of another embodiment of a multi-filament cable suitable for use in the present invention.
- axial and axialry refer to directions which are parallel to the axis of rotation of a tire
- radial and radially refer to directions that are perpendicular to the axis of rotation of a tire; “bead” refers to that part of a tire comprising an annular tensile member wrapped by ply cords and shaped, with or without other reinforcement elements to fit a designed tire rim;
- Carcass plies refers to the tire structure apart from the belt structure, tread, undertread, and sidewall rubber but including the beads, (carcass plies are wrapped around the beads);
- equatorial plane (EP) refers to a plane that is perpendicular to the axis of rotation of a tire and passes through the center of the tire's tread;
- belt or “belt ply” refers to an annular layer or ply of parallel cords, woven or unwoven, underlying the tread, not anchored to the bead, and having cord angles of from 12° to 35° with respect to the EP of the tire;
- breaker plies refers to annular reinforcement members in the crown area of a tire having longitudinal reinforcement members having an angle (in the illustrated embodiment) with respect to the equatorial plane of the tire of about 5° less than the angle of such reinforcement members in the bias carcass plies;
- “crown” refers to substantially the outer circumference of a tire where the tread is disposed; “rivet” refers to the amount of perpendicular distance between two adjacent cords;
- tenacity refers to breaking stress expressed as force per unit linear density of an unstrained specimen (cN/Tex or gm/denier), (usually used in textiles);
- modulus refers to the ratio of the change in stress to the change in strain
- organic refers to compounds, including polymers, containing a carbon backbone or structure, which can be shaped, stretched or formed into a particular physical configuration.
- a preferred embodiment of a pneumatic tire 10 which comprises a pair of substantially parallel annular beads 12.
- Carcass ply(ies) 14 are wrapped around the beads, belts or breakers 16 comprising three, steel cord reinforced breaker plies 18a, 18b, 18c and one organic polymer reinforced ply 20 disposed over the carcass ply(ies) 14 in a crown portion 22 of the tire.
- Tread 24 is disposed over the belts or breakers and sidewalls 26 are disposed between the tread and the beads.
- the carcass plies 14 and the breaker plies 18, as is common in the tire making art, are reinforced with substantially parallel, longitudinal reinforcing members.
- the present invention relates specifically to pneumatic tires which have a belt or breaker ply 20 which is at least partially reinforced by organic cords or filaments.
- the organic cords or filaments are formed of twisted yarns of any organic material, having sufficient strength and durability for the purpose described, can be used in the invention. Examples of such materials are thermoplastics such as polyamide; polyesters such as polyethyleneterephthalate (PET), and polyethylenenapthalate (PEN); and polyvinyl alcohol (PVA).
- longitudinal, reinforcing tire cords comprising polyamide, multi-filaments have been used in constructing ply 14.
- the polyamide multi-filaments used in the belt or breaker ply 20 comprise strands of yarn twisted together into a generally circular cross section as shown in Fig. 2.
- the organic multi-filaments are formed from about 420 dTex x 2 strands to about 3300 dTex x 3 strands of twisted yarn.
- the strands of material from about 420 dTex to about 2100 dTex are estimated to have a tenacity of at between about 35 cN/Tex to about 200 cN/Tex, an estimated initial modulus of at least 250 cN/Tex, an estimated elongation at break of about 2 to about 40%, and an estimated shrinkage of about 0.1% to about 10%.
- Multifilaments of polyamide are particularly well suited for implementing the invention.
- the multi-filament constructed from 420 dTex x 2 strands of twisted yarn twisted to between about 3 to about 20 turns per inch (about 1.2 to about 7.9 turns per centimeter) is smaller then that formed of 3300 dTex x 3 strands of yarn twisted to between about 3 to about 7 turns per inch (about 1.2 to about 2.8 turns per centimeter).
- the end count of the smaller 2 strand multi- filament is between about 10 to about 50 strands per inch (about 3.9 to about 19.7 strands per centimeter) while the end count of the larger three strand multi-filament is between about 5 to about 17 strands per inch (about 2.0 to about 6.7 strands per centimeter).
- multi-filaments 30 may be disposed in spaced, parallel relationship to one another as they are incorporated in an elastomeric material to form a top breaker ply 20 of the tire 10.
- Figs. 3 and 4 cross sections of polyamide multi-filaments 30 particularly suited for practicing the invention are illustrated.
- multi-filaments of two or three twisted strands as shown in Figs. 3 and 4, respectively, can be used.
- a suitable adhesive for example a conventional RFL adhesive, or the otherwise treat the multi- filaments to promote adherence of rubber to the multi- filaments.
- Another aspect of the present invention is the ability of the multi-filament construction to act as bleeder cords to prevent defects known as blows or blisters caused while curing the tire by the presence of air or other compressible gases within the body of the tire being cured.
- the tire when the tire is constructed, it is placed in a curing mold and heated after being inflated to a high pressure of about 400 pounds per square inch (psi) the top multi-filament reinforcement ply function as gas absorbing reinforcing cords embedded in rubber or rubber-like material.
- the gas or air can become trapped in or between the layers of materials which are superimposed on one another in the course of building the the, as previously discussed.
- the molecules of air can either be absorbed in the top multi-filaments embedded in rubber or rubberlike material. This feature of the present invention, reduces tire defects from local separation between the rubber and one or more of the reinforcement cords which make up the reinforcing ply of a pneumatic tire.
- the carcass ply 14 is wrapped over beads 12 such that reinforcement cords have an angle of between about 10° and about 90°, preferably about 90° with respect to the equatorial plane of the tire.
- the reinforcement members in belt or breaker plies 18a, 18b, 18c have an angle at least about 5° less than the angle of the reinforcement members in the carcass plies, and accordingly, the reinforcement members in the belt or breaker plies have an angle of between about 0° and about 35°, preferably about 22°, with respect to the equatorial plane of the tire.
- RMT tires have been made wherein the conventional construction has been changed by removing the top steel reinforced belt ply and replacing it with one polyamide multi-filament reinforced ply 20 over the three steel reinforced belt plies 18a, 18b, 18c.
- the end count for the steel reinforced plies may vary from about 8 to about 18 ends per inch (epi) ⁇ about 3.1 to about 7.1 ends per centimeter (epc) ⁇ .
- the multi- filament reinforced belt ply 20 has an angle of about 0° to about 35° with respect to the EP of the tire. It is within the terms of the invention for the multi-filament, non-wire reinforced ply 20 to extend beyond the edges of the other breaker plies 18a, 18b, 18c .
- the direction of the reinforcing multi-filaments is maintained at the same direction as the steel reinforcement cords in the breaker ply 18c next radially below.
- the top ply 20 wherein the cords have the same .angle as the reinforcement cord in the ply 18c below a less stiff belt package, that has improved flexibility and enveloping properties, is provided.
- the top belt in the belt package is a multi-filament, organic reinforced ply.
- Another important advantage of the improvement to the tires made according to the invention is improved retreadability because the damage to the top breaker is reduced.
- the time required for the buzz out operation (the grinding away of damaged spots created by the penetration of stones into the belt package) is shortened, and the possibility of breaker edge separation is reduced.
- These properties are beheved to be due, at least in part, to improved enveloping properties of the tread; improved aged adhesion possible between an organic cord or multi-filament and rubber as compared to the aged adhesion between rubber and steel; .and the corrosion resistance of the organic multi-filament reinforcement as compared to the corrosion resistance of steel.
Abstract
Description
Claims
Applications Claiming Priority (1)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
PCT/US1997/021161 WO1999025571A1 (en) | 1997-11-19 | 1997-11-19 | Radial medium truck tire with multifilament top belt |
Publications (1)
Publication Number | Publication Date |
---|---|
EP1047564A1 true EP1047564A1 (en) | 2000-11-02 |
Family
ID=22262100
Family Applications (1)
Application Number | Title | Priority Date | Filing Date |
---|---|---|---|
EP97948392A Withdrawn EP1047564A1 (en) | 1997-11-19 | 1997-11-19 | Radial medium truck tire with multifilament top belt |
Country Status (3)
Country | Link |
---|---|
EP (1) | EP1047564A1 (en) |
AU (1) | AU5447198A (en) |
WO (1) | WO1999025571A1 (en) |
Families Citing this family (5)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
FR2799411B1 (en) * | 1999-10-11 | 2002-05-24 | Michelin Soc Tech | IMPROVED ENDURANCE TIRE |
BR0015312A (en) * | 1999-11-05 | 2002-07-16 | Michelin Soc Tech | Pneumatic |
US7329459B2 (en) | 2003-03-07 | 2008-02-12 | Performance Fibers, Inc. | Polymer-based reinforcement material and tire cord compositions and methods of production thereof |
DE102019207014A1 (en) * | 2019-05-15 | 2020-11-19 | Continental Reifen Deutschland Gmbh | Reinforcement layer for a pneumatic vehicle tire |
KR20230009931A (en) * | 2020-06-23 | 2023-01-17 | 코드사 테크닉 테크스틸 아노님 시르케티 | High Tensile Nylon 6.6 Yarn |
Family Cites Families (7)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
JPS4937121B1 (en) * | 1968-08-27 | 1974-10-05 | ||
JPS6112408A (en) * | 1984-06-29 | 1986-01-20 | Yokohama Rubber Co Ltd:The | Aired radial tire for passenger car |
US5115853A (en) * | 1989-03-08 | 1992-05-26 | The Goodyear Tire & Rubber Company | Pneumatic tire with belt overlay structure reinforced with low denier nylon cords |
CA2018018C (en) * | 1989-08-10 | 1999-10-05 | Rene Francois Reuter | Pneumatic tire |
CA2023665C (en) * | 1990-03-22 | 1999-03-16 | Joanne Elizabeth Shaw | Bias ply aircraft tire |
JP3645277B2 (en) * | 1992-12-24 | 2005-05-11 | 株式会社ブリヂストン | Pneumatic tire |
US5743975A (en) * | 1995-03-24 | 1998-04-28 | The Goodyear Tire & Rubber Company | Radial medium truck tire with organic polymer reinforced top belt or breaker |
-
1997
- 1997-11-19 WO PCT/US1997/021161 patent/WO1999025571A1/en not_active Application Discontinuation
- 1997-11-19 AU AU54471/98A patent/AU5447198A/en not_active Abandoned
- 1997-11-19 EP EP97948392A patent/EP1047564A1/en not_active Withdrawn
Non-Patent Citations (1)
Title |
---|
See references of WO9925571A1 * |
Also Published As
Publication number | Publication date |
---|---|
AU5447198A (en) | 1999-06-07 |
WO1999025571A1 (en) | 1999-05-27 |
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Legal Events
Date | Code | Title | Description |
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PUAI | Public reference made under article 153(3) epc to a published international application that has entered the european phase |
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17P | Request for examination filed |
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STAA | Information on the status of an ep patent application or granted ep patent |
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