US-12623491-B2 - Pneumatic vehicle tire having a reinforcing layer with steel monofilaments

US12623491B2US 12623491 B2US12623491 B2US 12623491B2US-12623491-B2

Abstract

A pneumatic vehicle tire having a strength member ply comprising steel monofilaments having a cross-sectional area of 98 mm 2 to 125 mm 2 per meter of strength member ply, the steel has a carbon content of at least 0.86% by weight. To improve rolling resistance the monofilaments have a brass coating having a copper content of 61% by weight to 70% by weight and a zinc content of 30% by weight to 39% by weight, in that the monofilaments have a linear density of 92 g/100 m to 105 g/100 m, and the monofilaments each have a tensile density Td of 34 MPa/(g/100 m) to 39 MPa/(g/100 m). The strength member ply has an areal strength AS of 109 Nmm 2 to 166 Nmm 2 , and the rubber material has a breaking elongation of 300% to 450%.

Inventors

Daniel De Castro Pinho
Mihail Catana
Thomas Kramer
Michael Schunack

Assignees

CONTINENTAL REIFEN DEUTSCHLAND GMBH

Dates

Publication Date: 20260512
Application Date: 20230424
Priority Date: 20220531

Claims (17)

1 . A pneumatic vehicle tire comprising a strength member ply comprising strength members made of steel which are arranged within the strength member ply substantially parallel and spaced apart from one another and are embedded in a rubber material, wherein each of the strength members is configured as a monofilament, wherein the monofilaments occupy a cross-sectional area of 98 mm 2 to 125 mm 2 per meter of strength member ply and wherein the steel has a carbon content of at least 0.86% by weight, wherein: the monofilaments have a brass coating having a copper content of 61% by weight to 70% by weight and a zinc content of 30% by weight to 39% by weight, the monofilaments each have a linear density of 92 g/100m to 105 g/100m, the monofilaments have a tensile density Td of 34 MPa/(g/100m) to 39 MPa/(g/100m), wherein the tensile density Td is defined as the quotient of a tensile strength and the linear density of the respective strength member, the strength member ply has an areal strength AS of 109 Nmm 2 to 166 Nmm 2, wherein the areal strength AS is defined as the product of a breaking strength and a diameter d of a monofilament of the strength member ply and a spacing x between the monofilament and an adjacent monofilament of the strength member ply, the rubber material has a breaking elongation of 300% to 450%, and the monofilaments are free from twist about their axis.
2 . The pneumatic vehicle tire as claimed in claim 1 , wherein the monofilaments have a compression modulus of 138 GPa to 155 GPa and/or a compression displacement of 0.95% to 1.05% and/or a compression stress of 1400 MPa to 1500 MPa.
3 . The pneumatic vehicle tire as claimed in claim 1 , wherein the monofilaments each have an out-of-plane bending stiffness of 270 Nmm 2 to 340 Nmm 2 .
4 . The pneumatic vehicle tire as claimed in claim 1 , wherein the monofilaments each have a tensile strength of 3500 MPa to 3700 MPa.
5 . The pneumatic vehicle tire as claimed in claim 4 , wherein for the monofilaments a force of 285 N to 325 N must be applied for an elongation of 1%.
6 . The pneumatic vehicle tire as claimed in claim 1 , wherein the strength member ply has a weight fraction of steel of 47% by weight to 63.5% by weight, and wherein t the strength member ply has a spacing factor S of 2.00 to 2.67, wherein S=1+ ((y+y′+x)/(2×d)), wherein y is a thickness of the strength member ply on a first side of a monofilament of the strength member ply, y′ is a thickness of the strength member ply on an opposite second side of the monofilament, x is a spacing between the monofilament and an adjacent monofilament of the strength member ply and d is a diameter of the monofilament.
7 . The pneumatic vehicle tire as claimed in claim 6 , wherein the strength member ply has a weight fraction of steel of 48.9% by weight to 62.3% by weight and wherein t the strength member ply has a spacing factor S of 2.10 to 2.50.
8 . The pneumatic vehicle tire as claimed in claim 1 , wherein the rubber material has a tensile strength of 15 N/mm 2 to 22 N/mm 2 .
9 . The pneumatic vehicle tire as claimed in claim 1 , wherein the rubber material has a Shore hardness of 77 to 81 (Shore A).
10 . The pneumatic vehicle tire as claimed in claim 1 , wherein the rubber material has a rebound elasticity of 38 to 45.
11 . The pneumatic vehicle tire as claimed in claim 1 , wherein the pneumatic vehicle tire, comprises a belt and in that the strength member ply is a strength member ply of the belt.
12 . The pneumatic vehicle tire as claimed in claim 11 , wherein the tire is of radial construction, and wherein the belt has only two of said strength member plies, whose strength members cross at an angle of 18° to 45°.
13 . The pneumatic vehicle tire as claimed in claim 1 , wherein the pneumatic vehicle tire, comprises a carcass and in that the strength member ply is a strength member ply of the carcass.
14 . The pneumatic vehicle tire as claimed in claim 1 , wherein the monofilaments have a tensile strength of 3500 MPa to 3700 MPa, and wherein the monofilaments occupy a cross-sectional area of 119 mm 2 to 125 mm 2 per meter of strength member ply.
15 . The pneumatic vehicle tire as claimed in claim 14 , wherein the pneumatic vehicle tire is of radial construction, and comprises a belt, wherein the strength member ply is a strength member ply of the belt, the belt having only two of said strength member plies, whose strength members cross at an angle of 18° to 45°.
16 . The pneumatic vehicle tire as claimed in claim 1 , wherein the monofilaments have: a compression modulus of 138 GPa to 155 GPa, an out-of-plane bending stiffness of 270 Nmm 2 to 340 Nmm 2, a tensile strength of 3500 MPa to 3700 MPa, and a force of 285 N to 325 N must be applied for an elongation of 1%; and wherein the monofilaments occupy a cross-sectional area of 119 mm 2 to 125 mm 2 per meter of strength member ply, and wherein the strength member ply has an areal strength AS of 116 Nmm 2 to 166 Nmm 2 .
17 . The pneumatic vehicle tire as claimed in claim 16 , wherein the pneumatic vehicle tire is of radial construction, and comprises a belt, wherein the strength member ply is a strength member ply of the belt, the belt having only two of said strength member plies, whose strength members cross at an angle of 18° to 45°.

Description

This application is a National Stage Application under 35 U.S.C. § 371 of International Patent Application No. PCT/DE2023/200080 filed on Apr. 24, 2023, and claims priority from German Patent Application No. 10 2022 205 545.4 filed on May 31, 2022, the disclosures of which are herein incorporated by reference in their entireties. The invention relates to a pneumatic vehicle tire, especially of radial construction, having a strength member ply comprising strength members made of steel which are arranged within the strength member ply substantially parallel and spaced apart from another and are embedded in a rubber material, wherein each of the strength members is configured as a monofilament, wherein the monofilaments occupy a cross-sectional area of 98 mm2 to 125 mm2 per meter of strength member ply and wherein the steel has a carbon content of at least 0.86% by weight. A pneumatic vehicle tire generally comprises an air-impermeable inner layer, a carcass comprising at least one carcass strength member ply, wherein the carcass extends from the zenith region of the tire via the sidewalls into the bead region and is anchored there by being looped around tension-resistant bead cores, a radially outwardly arranged profiled tread and a belt comprising belt strength member plies which is arranged between the tread and the carcass and which may be radially outwardly covered with a belt bandage. The belt bandage may be a single-ply or multi-ply belt bandage and covers at least the belt edges. It is customary that for production of a strength member ply, in particular of the belt or the carcass, strength members are embedded in rubber material by running a set of substantially parallel strength members in the longitudinal direction through a calendar or an extruder for sheathing with the rubber material. These continuous webs are generally cut transversely to their longitudinal direction so that these parts may be employed in the tire as strength member plies individually or joined together. The belt generally comprises at least two belt strength member plies which are arranged such that they cross at an angle. The belt ensures the stiffness of the tread in the longitudinal and transverse direction. During driving this aids power transmission, improves lateral control, and reduces tire abrasion. The carcass comprises at least one carcass strength member ply, wherein in the case of a pneumatic vehicle tire of radial construction the strength members of the at least one carcass ply in the sidewalls are arranged at an angle of 0° to 10°, preferably of 0° to 8°, to the radial direction. It is known and customary for steel cords to be used as strength members of the belt. Belt strength member plies installed in pneumatic passenger car tires often have steel cords composed of a plurality of high-tensile steel filaments, for example of construction 2×, 3×, 2+1 etc. The disadvantage of belt strength member plies comprising the aforementioned steel cords is that they are relatively thick and heavy in weight which has an adverse effect on rolling resistance. To achieve thinner, rolling resistance-optimized strength member plies it is also known to employ thin steel monofilaments having a high strength member density. Thus, DE 10 2016 225231 A1 discloses a belt strength member ply comprising ultra-tensile steel monofilaments having a small diameter of 0.35 mm which, to compensate the small diameter, are arranged in the strength member ply at a high thread density of 90 epdm to 130 epdm. However, the elevated thread density to compensate the relatively low strength of the thin monofilaments compared to the cords composed of a plurality of steel filaments results in different challenges which affect for example the service life of the tire due to the high number of strength members and the lower strength member spacing. The high thread density can result in elevated crack formation and crack propagation. The deformation characteristics of the strength member ply and thus in particular the handling characteristics of the tire are also influenced by the configuration of the strength members. The primary object of the present invention was that of overcoming or at least reducing the above-described disadvantages of the prior art. It is accordingly an object of the present invention to provide a pneumatic vehicle tire which exhibits improved durability while retaining advantageous rolling resistance. This is achieved in that the monofilaments have a brass coating having a copper content of 61% by weight to 70% by weight and a zinc content of 30% by weight to 39% by weight, in that the monofilaments each have a linear density of 92 g/100 m to 105 g/100 m, in that the monofilaments each have a tensile density Td of 34 MPa/(g/100 m) to 39 MPa/(g/100 m), in that the strength member ply has an areal strength AS of 109 Nmm2 to 166 Nmm2 and in that the rubber material has a breaking elongation of 300% to 450%. The areal strength AS of a st