JP3059246B2 - Pneumatic tire - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION The present invention is reinforced with an organic filament yarn or cord which is substantially parallel to the radial direction and is axially folded about a pair of axially spaced bead cores. The present invention relates to a radial tire having a carcass composed of several plies.

[0002] The tire still comprises at least one belt ply, also reinforced with organic filament yarns or cords, located radially outward of the carcass ply in the crown region of the tire.

[0003]

BACKGROUND OF THE INVENTION In the tire art, tires used in aircraft are operated at extremely high speeds and under heavy loads compared to tires used in passenger cars, buses, trucks or similar ground vehicles. What is required is generally accepted. It is understood, however, that tires for such ground vehicles are advantageously made in accordance with the broad aspects of the invention described herein. Here and in the claims, "a tire is suitable for use in an aircraft" means that the tire is a tire rim yearbook for its year of manufacture (Yearbook of teh Tire and Rim Ass
ociation or Yearbook of the European Tire and Ri
m Technical Organization) or the current U.S. military standard "MIL-T-5041" for sizes and load ranges, or ply grades.

[0004]

SUMMARY OF THE INVENTION It is an object of the present invention to provide a radial pneumatic tire having a carcass that is lightweight and has excellent dimensional stability. Is to create a radial tire having

[0005]

SUMMARY OF THE INVENTION These objects are achieved according to the invention as set forth in the appended claims. The best mode currently conceivable for practicing the invention will be presented to enable those skilled in the art to understand the principles of the invention. Certain preferred embodiments of the present invention
The following description is made with reference to the accompanying drawings, which are a part of this specification.

[0006]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Referring to FIG.
The 8.8R16 tire 10 has a pair of substantially inextensible annular bead cores 11 spaced apart from each other in the axial direction, with several carcass plies 13, 14, 15 between them. Extending.

Here and in the claims,
Axial refers to a direction parallel to the axis of rotation of the tire, and radial refers to a direction radially toward or away from the axis of rotation of the tire. Each of the carcass plies 13-15 is connected to the equatorial plane (E
75 ° to 90 ° with respect to P), preferably 80 ° to 89 °
Includes several reinforcing elements located in the ° direction. The equatorial plane of the tire is a plane that is perpendicular to the axis of rotation of the tire and passes through the center of the tire tread, and the axial plane is a plane that includes the axis of rotation of the tire.

[0008] As a carcass ply, two turns
There are up carcass plies 13 and 14 and one turn down carcass ply 15. Each of the turn-up carcass plies 13, 14 is bent axially and radially outwardly about each bead core 11, and the turn-down carcass plies 15 are at least partially at least partially turned with each of the bead cores 11. It is bent radially and axially inward around the up carcass plies 13,14. Turn down carcass ply 15
Means that each edge of said turn-down carcass ply surrounds a bead core and that each bead core 1
It is bent to such an extent as to be inside the one axial center point 17 in the axial direction.

The reinforcing element of the innermost turn-up carcass ply 13 in the radial direction is 82 ° with respect to the equatorial plane EP.
And the reinforcing element of the second turn-up carcass ply 14 makes an angle of 85 ° with respect to the equatorial plane EP, and the reinforcing element of the turn-down carcass ply 15 makes an angle of 88 ° with the equatorial plane EP. Has been made. In a preferred embodiment of the invention, the direction of the reinforcing element of each carcass ply or two carcass plies is the direction of the radially inner one carcass ply or the reinforcing element of the two carcass plies. It should be noted that the angle should be closer to 90 ° than the direction, and the angle between both of the two carcass plies that are adjacent in the radial direction should be within 10 °, preferably within 4 °. For the selection of the optimal ply direction there, see US Pat.
No. 103 may be referred to. If the tire is tubeless, a layer that is almost impervious to air (not shown)
Are arranged radially inward of all carcass plies.

[0010] All the reinforcing elements of the carcass ply 13-15 are substantially the same, each made of 4,000 denier nylon monofilament. A monofilament is, by definition, a cord consisting of a single filament. The monofilament may have a circular cross-sectional shape, a slightly flattened substantially oval shape, or a strongly flattened shape with a rounded edge. Given a certain required strength, such flat filaments have a dimensional advantage and a smaller rivet area than filaments of ordinary circular cross-section for obtaining a given fabric density. The fabric density used in the description here (EPI or ends per i
Neither nch) nor the linear density is the density of the reinforcing elements in the plies that have not yet been molded. Preferably,
For a nylon monofilament cross-section, the maximum linear cross-sectional area or width should be 2-5 times the linear cross-sectional area or thickness perpendicular to the width.

The monofilaments in each ply are preferably arranged at a density of at least 14 EPI, preferably about 18 EPI, so as to obtain the desired mechanical properties of the tire carcass. Nylon monofilaments have an adhesion of at least 7 CN / denier, a tensile force of at least 40 CN / denier, an elongation at break of at least 18%, and a shrinkage of up to 4%. For additional details on monofilaments, see 198
No. 345,92 of a concurrent application filed on May 1, 2009
It is shown in No. 5.

In the crown area of the tire 10, outside the carcass plies 13 to 15, there is a belt 20. A tread portion 30 that contacts the ground is provided radially outside the belt structure 20.
Are arranged, and the sidewall portion 26 extends radially inward from each of the axial end edges of the tread portion to the bead portion 28, respectively.

Each of the belt plies 21 to 23 includes a high-twisted aramid cord having a fabric density of 10 to 35 EPI, which is parallel to each other, is in a direction of 10 to 40 degrees with respect to the equatorial plane EP of the tire, and has a fabric density of 10 to 35 EPI. I have. As used herein, both aramid and aromatic polyamide are materials in which the fiber-forming substance is generally a long-chain aromatic polyamide (provided that at least 85% of the amide linkages are directly attached to two paromatic rings). It is understood to mean a manufactured fiber which is recognized as being. Representative of the aramid or aromatic polyamide is poly, i.e., p-phenylene terephthalamide. A twisted aramid cord, which is one embodiment of the present invention used as a reinforcing element in a tire tread reinforcing structure, has a twist multiple (TM) in the range of 7-9. The twist multiple is

[0014]

(Equation 1) Where CT is a code length of 1 inch (2.
The number of turns per 54 cm), CD, is the sum of denier of the cord yarns and / or yarn subgroups when they are not twisted.

In a low twist aramid cord used in another embodiment of the present invention as a reinforcing element for a tire belt where strength is less important, the twist multiple is four.
~ 7. Belt plies reinforced with high twist aramid cords provide tires with optimal carcass-belt compatibility and durability.
It is believed that a belt ply reinforced with twisted aramid cord may optimize the landing capacity of aircraft tires. For more information on high twist and low twist aramid cords, see U.S. Pat.
No. 32,102.

The belt 20 includes two belt plies 22,
One belt ply 2 folded around 23
Including 1. The folded ply has a high twist of 1,500 / 500 with a fabric density of about 14 EPI at an angle between 18 ° and 26 ° with the equatorial plane of the tire.
It is reinforced with 3-denier aramid. Ply 22,
23 is also reinforced with 1,500 / 3 denier high twist aramid cord, which has a fabric density of about 18 EPI. The angles between the reinforcing elements of these two plies and the equatorial plane of the tire are opposite and
It is between 2 ° and 24 °, preferably between 16 ° and 20 °.

The tread portion 30 to be grounded and the belt structure 20
At least one overlay ply 29 reinforced with 840/2 denier nylon cord is disposed therebetween. The nylon cord has a fabric density of about 22 EPI and is parallel to each other in each ply. Although the overlay ply only contributes slightly to the characteristics and high speed performance of the tire, it is said that its primary function is to protect the belt 20 during the tread update process. That is, as the elastomeric material making up the tire tread is removed by buffing during tread renewal, the overlay ply acts as a visual alert layer.

It is believed that the placement of the reinforcing strip at the bead portion of the tire contributes to the performance of the product, especially its durability. In addition, the reinforcing strip that is folded around the bead core compensates for constraints on the ends of the plies in shaping the tire. In the embodiment shown in FIG. 1, at least a portion of one strip 41 reinforced with 840/2 denier nylon cord comprises
The innermost turn-up carcass ply 1 in the radial direction
3 and the turn-up carcass ply 14 adjacent thereto. Preferably, a portion of the reinforcing strip 41 extends radially inward of the apex 43, extends radially outward of the apex 43, and extends toward the sidewall. The nylon cord of the reinforcing strip 41 has an angle of 30 with respect to the axial plane intersecting the cord.
It is sufficient that the angle is between 60 ° and 60 °, preferably between 40 ° and 50 °. Apex 43 is Shore A
It is made of rubber having a hardness of 76 to 84.

Between the radially outermost turn-down carcass ply 15 and the chafer 44, there are two additional reinforcing plies 45, 46, also known in the art as semi-chippers. These semi-chippers are 20-70 ° to the axial plane past the cord
, More desirably reinforced with a nylon cord having a slope between 40 ° and 50 °. Reinforcement ply 45,
It is believed that 46 disperses shear and compression stresses due to tire flexure. Semi chippers 45, 46
And between the turn-down carcass ply 15 is a rubber strip 47 having a Shore A hardness of about 62.

In FIG. 2, the linear density is about 4,000
A tire 210 is shown that includes carcass plies 213-215 reinforced with nylon monofilament having 0 denier and a fabric density of about 18 EPI. The cross-sectional shape of the monofilaments of all plies is strongly flattened with rounded edges.

The belt 220 reinforced with a low twist aramid cord has two belt plies 222,
223 includes a single belt ply 221 that is folded around 223. The folded plies are at an angle of between 18 ° and 26 ° to the equatorial plane of the tire, more preferably between 20 ° and 24 °, and have a fabric density of about 1500 EPI with a fabric density of about 16 EPI. Reinforced with denier aramid cord. Plies 222, 22
3 is reinforced with an aramid cord having a linear density of about 1,500 / 3 denier and a fabric density of about 16 EPI. The angles formed by the reinforcing cords of these two plies 222 and 223 with respect to the equatorial plane of the tire are opposite to each other.
It is between 0 ° and 26 °, preferably between 16 ° and 20 °.

Tread 230 to be grounded and belt structure 2
It can be seen that there is one overlay ply 229 reinforced with nylon between the two. This is to protect the belt 220 during the tread update process.

In the bead portion of the tire, 840/2
The two strips 241 and 242 reinforced with denier nylon cord form a radially outer turn
It is interposed between the up carcass ply 214 and the apex 243. These reinforcement strips extend from the bead core 211 at least along the entire height of the apex 243 toward the sidewall. The nylon cords of the reinforcing strips 241, 242 are arranged at an angle of between 30 ° and 60 °, preferably between 40 ° and 50 °, with respect to the axial plane intersecting the cords.

Between the radially outermost turn-down carcass ply 215 and the chafer 244 are two semi-chippers 245, 246. These semi-chippers have an inclination of 50 with respect to the axial plane intersecting with the cord.
Reinforced with nylon cords between ° and 70 °.

FIG. 3 shows a partial cross section of a tire including two turn-up carcass plies 313, 314 and two turn-down carcass plies 315, 316. These carcass plies have a linear density of 840/2 denier and a fabric density of 24 EP
I is reinforced with nylon monofilament. The cross-section of the monofilament in all plies is strongly flattened with rounded edges.

The belt 320 is reinforced with a high twist aramid cord and has three belt plies 322.
One belt ply 3 folded around .about.324
21. The folded plies are at an angle between 18 ° and 26 ° with the equatorial plane of the tire and are reinforced with 1,500 / 3 denier aramid cord with a fabric density of about 14 EPI. The three plies 322 to 324 are reinforced with a 1500/3 denier aramid cord having a fabric density of about 16 EPI. The angle formed by the reinforcing cords of these three plies with the equatorial plane of the tire is opposite between adjacent plies, and
Between 0 ° and 24 °. In the preferred embodiment of the present invention, the angle values of these plies are -16 ° for the radially innermost ply and about + 18 ° and -18 ° for the two radially outer plies, respectively. .

Tread 330 to be grounded and belt structure 3
Between the two, one overlay ply 329 reinforced with a nylon cord is arranged. As mentioned above, such overlays are particularly important in the tread update process.

It should be understood that the belt and carcass structures shown in FIGS. 1, 2 and 3 and described herein are merely examples used in the preferred embodiment. Depending on the performance requirements of the particular tire, tire designers may use various carcass plies reinforced with nylon monofilaments having various cross-sectional shapes, various linear and fabric densities in the practice of the present invention. Could be used with other structures, unfolded or otherwise reinforced belt plies reinforced with high twist or low twist aramid cords.

[Brief description of the drawings]

FIG. 1 is a sectional view of a tire according to a first embodiment of the present invention in a plane including an axis of tire rotation.

FIG. 2 is a sectional view of a tire according to a second embodiment of the present invention in a plane including an axis of tire rotation.

FIG. 3 is a partial enlarged view of a belt of a tire according to a further embodiment of the present invention.

[Explanation of symbols]

 Reference Signs List 10 tire (whole) 11 bead core 13, 14 turn-up carcass ply 15 turn-down carcass ply 17 center of bead core 20 belt (whole) 21 to 23 belt ply 26 sidewall 28 bead part, 29 overlay ply 30 tread part 41 reinforcement Strip 43 Apex 44 Chafer 45,46 Reinforcement ply (semi-chipper) 47 Rubber strip 210 Tire (whole) 211 Bead core 213,214 Turn up carcass ply 215 turn, down carcass ply 220 Belt (whole) 221 to 223 Belt ply 229 Overlay Ply 230 Tread portion 241,242 Reinforcement strip 243 Apex 244 Chafer 245,246 Reinforcement ply (Semi-chipper 313, 314 Turn-up carcass ply 315, 316 Turn-down carcass ply 320 Belt (overall) 321-324 Belt ply 329 Overlay ply 330 Tread portion

──────────────────────────────────────────────────続 き Continuation of front page (73) Patent holder 590002976 1144 East Market Street, Akron, Ohio 44316-0001, U.S.A. S. A. (72) Inventor Stanley Navow Belgium 6600 Bastouen Showa Dallon 49 (72) Inventor Pie Wermer Luxembourg 9169 Merzig Liu Du Merscheid 23 (56) References JP-A 4-271903 (JP, A) JP-A Heisei 1-148828 (JP, A) JP-A-46-47099 (JP, A) (58) Fields investigated (Int. Cl. ⁷ , DB name) B60C 9/00 B60C 9/08 B60C 9/18

Claims (5)

(57) [Claims] 1. An axially spaced apart 1
At least two carcass plies (13 to 15, 213 to 215), at least a part of which are wound around the pair of bead cores (11, 211) in the axial direction, and the carcass ply (13) in a crown region of the tire. ~ 1
5, pneumatic tires (10, 210) having two or more belt plies (21 to 23, 221 to 223) arranged radially outside of each of the carcass plies (5, 213 to 215). 13-15, 213-215)
Flat with a linear density of at least 2,500 denier, a fabric density of at least 12 EPI, and a maximum linear cross-sectional area (ie, width) of 2 to 5 times the linear cross-sectional area perpendicular to the width. A belt ply (21-33) having a plurality of mutually parallel reinforcing elements of nylon monofilaments of cross-sectional shape and oriented at an angle of 75-90 with respect to the equatorial plane (EP) of the tire; 23, 221-223) are made of aramid and have a linear density of at least 2,0.
00 denier, fabric density at least 10 EP
I. A pneumatic tire for an aircraft, wherein the tire is I. 2. A belt ply (21-23, 221-2)
23) are reinforced with aramid cords having a linear density of at least 3,000 denier and a fabric density of 10 to 25 EPI, and these reinforcing cords are at 10 ° to the equatorial plane (EP) of the tire (10, 210). The pneumatic tire according to claim 1, wherein the tire forms an angle of 35 °, and an angle between the reinforcing cord and an equatorial plane (EP) of the tire is opposite between two adjacent plies. 3. A high twist aramid cord having a linear density of at least 4,000 denier, a fabric density of 12 to 20 EPI and an angle between 18 ° and 24 ° with respect to the equatorial plane (EP) of the tire. One reinforced belt ply (21-23, 221-223) is folded and reinforced with a high twist aramid cord with a fabric density of 12-20 EPI and an angle of 15 ° -24 ° with the equatorial plane of the tire The pneumatic tire according to claim 2, wherein the two plies are wrapped. 4. A reinforced low twist aramid cord having a linear density of at least 4,000 denier, a fabric density of 10-18 EPI, and an angle between 18 ° and 26 ° with the tire's equatorial plane. One belt ply (21-23, 221-223) was folded and reinforced with a low twist aramid cord with a fabric density of 10-18 EPI and an angle between 14 ° and 22 ° with the tire's equatorial plane 3. The pneumatic tire according to claim 2, wherein the pneumatic tire encloses two plies. 5. At least two turn-up carcass plies (13, 14, 213, 214) and at least one turn-down carcass ply (15, 21).
5), wherein each turn-up carcass ply is wound around each bead core (11, 211) in the axial direction and radially outward, and each turn-down carcass ply is provided with a turn-up carcass ply. The at least one strip (41, 241, 242) wrapped at least partially in the axial direction with respect to the apex (43, 2
43) and the radially outermost turn-up carcass ply (14,
214), and strips (241, 241) extending from the bead core (211).
The pneumatic tire according to claim 1, wherein 242) extends at least along the entire height of the apex (243) into the side wall.