High modulus textile cord with an at least triple twist
A high modulus textile cord ( 50 ) with at least triple twist (T1, T2, T3) comprises at least N strands ( 20 a, 20 b, 20 c, 20 d ), N being greater than 1, twisted together with a final twist T3 and a final direction D2, each strand being made up of M pre-strands ( 10 a, 10 b, 10 c ), M being greater than 1, themselves twisted together with an intermediate twist T2 (T2a, T2b, T2c, T2d) and an intermediate direction D1 opposite to D2, each pre-strand itself consisting of a yarn ( 5 ) which has been twisted on itself beforehand with an initial twist T1 (T1a, T1b, T1c) and the direction D1, in which at least half of the N times M yarns have an initial elastic modulus denoted Mi which is greater than 2000 cN/tex. This textile cord can advantageously be used as a reinforcer in tires for vehicles, particularly in the belt or carcass reinforcement of these tires.
1. A tire reinforced with a textile cord with at least triple twist, the textile cord comprising:
at least N strands, N being greater than 1, twisted together with a twist (T3) and a direction (D2),
wherein each strand is made up of M pre-strands, M being greater than 1, themselves twisted together with a twist (T2) and a direction (D1) opposite to the direction (D2),
wherein each pre-strand consists of a yarn which has been twisted on itself with a twist (T1) and the direction (D1) opposite to the direction (D2),
wherein the sum of the twist (T1) measured in turns per meter and of the twist (T2) measured in turns per meter is between 0.8 and 1.2 times the twist (T3) measured in turns per meter,
wherein the twist (T2) measured in turns per meter comprises between 0.4 and 0.8 times the twist (T3) measured in turns per meter,
wherein N strands multiplied by M pre-strands equals a total number of yarns,
wherein at least half of the yarns have an initial elastic modulus denoted Mi which is greater than 2000 cN/tex, and
wherein each yarn is made of a polymer material.
2. The tire according to claim 1 , wherein N varies in a range from 2 to 6.
3. The tire according to claim 2 , wherein N varies in a range from 2 to 4.
4. The tire according to claim 1 , wherein M varies in a range from 2 to 6.
5. The tire according to claim 4 , wherein M varies in a range from 2 to 4.
6. The tire according to claim 1 , wherein the total number of yarns is in a range from 4 to 25.
7. The tire according to claim 6 , wherein the total number of yarns is in a range from 4 to 16.
8. The tire according to claim 1 , wherein the twist (T1), expressed in turns per meter, is between 10 and 350 turns per meter.
9. The tire according to claim 8 , wherein the twist (T1) is between 20 and 200 turns per meter.
10. The tire according to claim 1 , wherein each pre-strand has a twist coefficient (K1) which is between 2 and 80.
11. The tire according to claim 10 , wherein the twist coefficient (K1) of each pre-strand is between 6 and 70.
12. The tire according to claim 1 , wherein the twist (T2), expressed in turns per meter, is between 25 and 470 turns per meter.
13. The tire according to claim 12 , wherein the twist (T2) is between 35 and 400 turns per meter.
14. The tire according to claim 1 , wherein each strand has a twist coefficient (K2) which is between 10 and 150.
15. The tire according to claim 14 , wherein the twist coefficient (K2) of each strand is between 20 and 130.
16. The tire according to claim 1 , wherein the twist (T3), expressed in turns per meter, is between 30 and 600 turns per meter.
17. The tire according to claim 16 , wherein the twist (T3) is between 80 and 500 turns per meter.
18. The tire according to claim 1 , wherein the cord has a twist coefficient (K3) which is between 50 and 500.
19. The tire according to claim 18 , wherein the twist coefficient (K3) of the cord is between 80 and 230.
20. The tire according to claim 1 , wherein the twist (T2) measured in turns per meter is greater than the twist (T1) measured in turns per meter.
21. The tire according to claim 1 , wherein the twist (T3) measured in turns per meter is greater than the twist (T2) measured in turns per meter.
22. The tire according to claim 1 , wherein the sum of the twist (T1) measured in turns per meter and of the twist (T2) measured in turns per meter is between 0.9 and 1.1 times the twist (T3) measured in turns per meter.
23. The tire according to claim 1 , wherein the sum of the twist (T1) measured in turns per meter and of the twist (T2) measured in turns per meter is equal to the twist (T3) measured in turns per meter.
24. The tire according to claim 1 , wherein all of the yarns have a modulus Mi greater than 2000 cN/tex.
25. The tire according to claim 24 , wherein all of the yarns have a modulus Mi greater than 2500 cN/tex.
26. The tire according to claim 1 , wherein at least half of the yarns have a modulus Mi greater than 3000 cN/tex.
27. The tire according to claim 1 , wherein each yarn is made of one or several materials selected from the group consisting of celluloses, polyvinyl alcohols, polyketones, aromatic polyamides, aromatic polyesters, polybenzazoles, polyimides, and polyesters.
28. The tire according to claim 27 , wherein each yarn is made of aromatic polyamides.
29. A method of reinforcing a tire comprising a step of including a textile cord with at least triple twist in the tire, the textile cord comprising:
at least N strands, N being greater than 1, twisted together with a twist (T3) and a direction (D2),
wherein each strand is made up of M pre-strands, M being greater than 1, themselves twisted together with a twist (T2) and a direction (D1) opposite to the direction (D2),
wherein each pre-strand consists of a yarn which has been twisted on itself with a twist (T1) and the direction (D1) opposite to the direction (D2),
wherein the sum of the twist (T1) measured in turns per meter and of the twist (T2) measured in turns per meter is between 0.8 and 1.2 times the twist (T3) measured in turns per meter,
wherein the twist (T2) measured in turns per meter comprises between 0.4 and 0.8 times the twist (T3) measured in turns per meter,
wherein N strands multiplied by M pre-strands equals a total number of yarns,
wherein at least half of the yarns have an initial elastic modulus denoted Mi which is greater than 2000 cN/tex, and
wherein each yarn is made of a polymer material.