Two-layer multi-strand cords having very low, low and medium moduli

Patent metadata

Field	Value
Publication number	US-11458772-B2
Application number	US-201816956147-A
Country	US
Kind code	B2
Filing date	Dec 19, 2018
Priority date	Dec 19, 2017
Publication date	Oct 4, 2022
Grant date	Oct 4, 2022

Abstract

A two-layer multi-strand cord (60) comprises an internal layer (CI) of the cord made up of J>1 internal strands (TI) and an external layer (CE) of the cord made up of L>1 external strands (TE). The cord satisfies the relationship 95≤MC≤175, where MC=(J×MI+L×ME)/(J+L); MI=200×cos4(α)×[Q×(D1/2)2×cos4(β)+N×(D2/2)2×cos4(γ)]/[Q×(D1/2)2+N×(D2/2)2]; and ME=200×cos4(α′)×[Q′×(D1′/2)2×cos4(β′)+P′×(D2′/2)2×cos4(δ′)+N′×(D3′/2)2×cos4(β′)]/[Q′×(D1′/2)2+P′×(D2/2)2+N′×(D3′/2)2], where D1, D1′, D2, D2′, and D3′ are in mm, α and α′ are the helix angle of each internal and external strand (TI), β and β′ are the helix angle of each internal thread (F1, F1′), δ′ is the helix angle of each intermediate thread (F2′) and γ and γ′ are the helix angle of each external thread (F2, F3′).

First claim

The invention claimed is:

1. A two-layer multi-strand cord comprising:
an internal layer of the cord made up of J>1 internal strands wound in a helix, each internal strand having two layers and comprising an internal layer made up of Q>1 internal threads of diameter D1, and an external layer made up of N>1 external threads of diameter D2 wound around the internal layer; and
an external layer of the cord made up of L>1 external strands wound around the internal layer of the cord, each external strand having three layers and comprising an internal layer made up of Q′≥1 internal threads of diameter D1′, an intermediate layer made up of P′>1 intermediate threads of diameter D2′ wound around the internal layer, and an external layer made up of N′>1 external threads of diameter D3′ wound around the intermediate layer,
wherein the cord satisfies the following relationship:
95≤ MC≤ 175

where MC =( J×MI+L×ME )/( J+L )
where MI= 200×cos 4 (α)×[ Q ×( D 1/2) 2 ×cos 4 (β)+ N ×( D 2/2) 2 ×cos 4 (γ)]/[ Q ×( D 1/2) 2 +N ×( D 2/2) 2 ],

where D1 and D2 are expressed in mm, α is the helix angle of each internal strand in the internal layer of the cord, β is the helix angle of each internal thread in the internal layer within each internal strand, and γ is the helix angle of each external thread in the external layer within each internal strand,
where ME= 200×cos 4 (α′)×[ Q ′×( D 1′/2) 2 ×cos 4 (β′)+ P ′×( D 2′/2) 2 ×cos 4 (δ′)+ N ′×( D 3′/2) 2 ×cos 4 (γ′)]/[ Q ′×( D 1′/2) 2 +P ′×( D 2/2) 2 +N ′×( D 3′/2) 2 ], and

where D1′, D2′ and D3′ are expressed in mm, α′ is the helix angle of each external strand in the external layer of the cord, β′ is the helix angle of each internal thread in the internal layer within each external strand, δ′ is the helix angle of each intermediate thread in the intermediate layer within each external strand, and γ′ is the helix angle of each external thread in the external layer within each external strand.

2. The two-layer multi-strand cord according to claim 1 , wherein 95≤MC≤170.

3. The two-layer multi-strand cord according to claim 1 , wherein 71≤MI≤192.

4. The two-layer multi-strand cord according to claim 1 , wherein 71≤ME≤181.

5. The two-layer multi-strand cord according to claim 1 , wherein 0.70≤ME/MI≤1.30.

6. The two-layer multi-strand cord according to claim 1 , wherein the helix angle α of each internal strand in the internal layer of the cord ranges from 3° to 36°.

7. The two-layer multi-strand cord according to claim 1 , wherein the helix angle α′ of each external strand in the external layer of the cord ranges from 10° to 34°.

8. The two-layer multi-strand cord according to claim 1 , wherein 16°≤2α+β+γ≤105°.

9. The two-layer multi-strand cord according to claim 1 , wherein 47°≤3α′+β′+δ′+γ′≤147°.

10. The two-layer multi-strand cord according to claim 1 , wherein 84°≤2α+β+γ+3α′+β′+δ′+γ′≤226°.

11. The two-layer multi-strand cord according to claim 1 , wherein J=2, 3 or 4.

12. The two-layer multi-strand cord according to claim 1 , wherein L=7, 8, 9 or 10.

13. The two-layer multi-strand cord according to claim 1 , wherein the external layer of the cord is desaturated.

14. The two-layer multi-strand cord according to claim 1 , wherein the cord has a modulus EC such that 50 GPa≤EC≤160 GPa.

15. A tire comprising the two-layer multi-strand cord according to claim 1 .

Assignees

• Michelin & Cie

Inventors

• Clement Emmanuel
• Barbat Romain
• Chevalley Marianna
• Gianetti Alexandre
• Laurent Stephane

Classifications

• B60C2009/0092

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• D07B2201/1076

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• D07B2201/1068

  having the same lay direction · CPC title

• D07B2501/2046

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