Pneumatic vehicle tire comprising reinforcement layer with steel filaments

Abstract

The present invention relates to a vehicle pneumatic tire having a strength member layer comprising steel filaments having a cross-sectional area of 98 mm2 to 125 mm2 per meter of the strength member layer wherein the steel has a carbon content of at least 0.86% by weight. The aim of the invention is to provide improved long-term durability while maintaining favorable rolling resistance. This is achieved in that the monofilament has a brass coating having a copper content of 61% to 70% by weight and a zinc content of 30% to 39% by weight; the monofilaments have a linear density of 92 g / 100 m to 105 g / 100 m; the monofilaments each having a tensile density Td of 34 MPa / (g / 100 m) to 39 MPa / (g / 100 m), where the tensile density Td is defined as the quotient of the tensile strength and the linear density of the respective strength member; the strength member layer has an area strength AS of 109 Nmm2 to 166 Nmm2, the area strength AS being defined as a product of a breaking strength and a diameter of a monofilament, and a pitch between the monofilament and an adjacent monofilament of the strength member layer; and the rubber material has an elongation at break of 300% to 450%.

Description

Technical Field

[0001] The present invention relates to a vehicle pneumatic tire, in particular a vehicle pneumatic tire of radial construction, the vehicle pneumatic tire having a strength member layer, the strength member layer comprising strength members made of steel, the strength members being arranged in the strength member layer, substantially parallel and spaced apart from each other and embedded in a rubber material, wherein each of the strength members is configured as a monofilament, wherein the monofilament occupies 98 mm per meter of the strength member layer 2 Up to 125mm 2 A cross-sectional area of ​​1000 mm / s and wherein the steel has a carbon content of at least 0.86% by weight. Background Art

[0002] The vehicle pneumatic tire generally comprises: an airtight inner layer; a carcass comprising at least one carcass strength member layer, wherein the carcass extends from the apex region of the tire via the sidewalls into the bead region and is anchored there by surrounding a tension-resistant bead core ring; a radially outwardly arranged profiled tread; and a belt comprising a belt strength member layer, which is arranged between the tread and the carcass and can be covered radially outwardly by a belt band. The belt band can be a single-layer or multi-layer belt band and covers at least the belt edge.

[0003] It is customary to embed the strength members in a rubber material by passing a set of substantially parallel strength members through a calender or extruder in the longitudinal direction in order to produce strength member layers, in particular belts or carcasses, for coating with the rubber material. These continuous webs are usually cut transversely to their longitudinal direction so that the portions can be used individually or joined together as strength member layers in a tire.

[0004] The belt generally comprises at least two layers of belt strength members arranged so that they cross at an angle. The belt ensures the stiffness of the tread in the longitudinal and transverse directions. During driving, this helps power transmission, improves lateral control and reduces tire wear.

[0005] The carcass comprises at least one carcass strength member layer, wherein in the case of a vehicle pneumatic tire with radial construction the strength members of at least one carcass layer in the sidewall are arranged at an angle of 0° to 10°, preferably 0° to 8° to the radial direction.

[0006] It is known and customary to use steel cords as belt strength members. The belt strength member layers installed in passenger car pneumatic tires usually have steel cords consisting of a plurality of high tensile steel filaments (e.g., with configurations 2x, 3x, 2+1, etc.). The disadvantage of belt strength member layers comprising the above-mentioned steel cords is that they are relatively thick and heavy, which has an adverse effect on rolling resistance.

[0007] In order to achieve a thinner, rolling resistance-optimized strength component layer, it is also known to use thin steel monofilaments with a high strength component density. Thus, DE 10 2016 225231 A1 discloses a belt strength component layer, which comprises super-stretched steel monofilaments with a small diameter of 0.35 mm, which are arranged in the strength component layer with a high linear density of 90 epdm to 130 epdm to compensate for the small diameter.

[0008] However, the increased linear density used to compensate for the relatively low strength of the thin monofilaments compared to a cord consisting of a plurality of steel filaments leads to different challenges, which for example affect the service life of the tire due to the high number of strength members and the low strength member spacing. The high linear density may lead to increased crack formation and crack propagation. The deformation characteristics of the strength member layer and therefore in particular the handling characteristics of the tire are also affected by the configuration of the strength members. Summary of the invention

[0009] The main object of the present invention is to overcome or at least reduce the above-mentioned disadvantages of the prior art.

[0010] It is therefore an object of the present invention to provide a vehicle pneumatic tire which exhibits improved durability while maintaining favorable rolling resistance.

[0011] This is achieved by: the monofilaments having 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 having a linear density of 92 g / 100 m to 105 g / 100 m; the monofilaments each having a tensile density Td of 34 MPa / (g / 100 m) to 39 MPa / (g / 100 m); the strength member layer having a tensile strength of 109 Nmm 2 Up to 166Nmm 2 The area strength AS of the strength member layer is defined as the product of the breaking strength and diameter of the strength member of the strength member layer and the spacing between the strength member and the adjacent strength member of the strength member layer. Therefore, the spacing plus the diameter is the repeating spacing of the strength member. The breaking strength of the strength member is measured according to ASTM D2969.

[0012] The cross-sectional area of ​​the monofilaments is perpendicular to the extension direction of the monofilaments. In the context of the present invention, the tensile density Td of a strength member is the quotient of the tensile strength and the linear density of the corresponding strength member. The tensile strength is measured according to ASTM D 2969.

[0013] The elongation at break of the rubber material is measured according to DIN 53504 at room temperature.

[0014] The high carbon content of the steel of the monofilament of at least 0.86% by weight enables the monofilament to obtain an advantageously high tensile strength. Forming the strength member as a monofilament allows particularly good penetration with the rubber material, which avoids the propagation of corrosion caused by the high carbon content. At the same time, the implementation of the strength member as a monofilament still allows a thin configuration of the strength member layer and thus still allows low rolling resistance. The brass coating of the monofilament with a copper content of 61% by weight to 70% by weight and a zinc content of 30% by weight to 39% by weight promotes optimal adhesion between steel and rubber material. This results in improved durability of the tire and low rolling resistance.

[0015] The relatively high linear density of the monofilaments of 92 g / 100 m to 105 g / 100 m (measured in g per 100 m length of the respective monofilament) results in improved compression properties and therefore improved handling properties when used as a belt layer. At the same time, this high linear density together with the low tensile density Td of 34 MPa / (g / 100 m) to 39 MPa / (g / 100 m) ensures reduced signs of fatigue and therefore greater durability.

[0016] It has been found that the interaction between the strength member and the rubber material covering the strength member (particularly the amount of rubber material used for the covering and its elongation at break) is particularly important for the tire properties. Therefore, the area strength is taken into account and the breaking strength is combined with the diameter of the monofilament and the spacing to adjacent monofilaments. It has been found that 109 Nmm 2 Up to 166Nmm 2 The area strength AS of 300% in combination with the high linear density according to the invention and in particular the elongation at break of the rubber material arranged between the strength members of 300% to 450% allows an excellent compromise between the service life, handling characteristics and robustness of the tire. Such a strength carrier layer exhibits improved characteristics with regard to crack formation and crack propagation.

[0017] Accordingly, the present invention provides a vehicle pneumatic tire that still provides favorable rolling resistance and improved durability through the arrangement and weight distribution of steel and rubber materials in the strength member layer, and the material properties of the rubber material. These advantages are particularly evident in the case of a vehicle tire that includes a strength member layer as a belt layer. This vehicle pneumatic tire has favorable handling characteristics.

[0018] Compared to strength member layers having strength members of a conventional 2x high tensile configuration, it is possible to produce a vehicle pneumatic tire that exhibits improvements in rolling resistance, handling and valve needle, while still having a favorable service life and robustness of the tire.

[0019] Advantageous embodiments are provided 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.

[0020] It has been found that this combination of steel monofilaments and rubber material in the strength member layer together with a compression modulus of 138 GPa to 155 GPa and / or a compression displacement of 0.95% to 1.05% and / or a compressive stress of 1400 MPa to 1500 MPa enables high compressive strengths up to filament buckling. This results in further improved deformation properties of the strength member layer. When used as a belt layer, this correspondingly results in a vehicle pneumatic tire that is further improved in terms of handling properties. It is advantageous when the monofilaments have a compression modulus of 138 GPa to 155 GPa and a compression displacement of 0.95% to 1.05% and a compressive stress of 1400 MPa to 1500 MPa.

[0021] The determination of the compression modulus, compression displacement and compression stress of steel strength members (in particular monofilaments) is known to those skilled in the art. In order to determine the corresponding characteristics of a monofilament, a sample of the following rubber cylinder (in particular a rubber cylinder consisting of the same rubber material as the rubber material of the strength member layer) is usually tested compared to a sample consisting of a corresponding rubber cylinder without such a monofilament, the rubber cylinder comprising the monofilament arranged along the rotation axis of the cylinder. The corresponding cylinder can have a diameter of 15 mm and a length of 25 mm, and the test can be carried out at room temperature with a preload of 2 N and a test speed of 5 mm / min. In order to determine the compression characteristics of the monofilament, the difference between two samples with and without the monofilament is considered.

[0022] An advantageous embodiment is provided in which the monofilaments each have a strength of 270 Nmm 2 Up to 340Nmm 2 Out-of-plane bending stiffness.

[0023] It has been found that the combination of steel monofilaments and rubber material in the strength member layer of the invention together with the monofilaments in each case 270 Nmm 2 Up to 340Nmm 2 The high out-of-plane bending stiffness of the resulting pneumatic vehicle tire is optimized with respect to the deformation properties of the strength member layer. When used as a belt layer, this correspondingly results in a pneumatic vehicle tire that is further optimized in terms of handling properties.

[0024] The bending stiffness of steel strength members, in particular monofilaments, can be determined by a 3-point bending test known to the person skilled in the art. In this case, the bending stiffness of the monofilament is determined by the forces acting on the strength member perpendicularly to the extension direction of the monofilament. In this case, linear monofilament pieces are tested, wherein the test length and the distance between the two contact points at which the monofilament is supported depend on the linear density of the monofilament.

[0025] Advantageous embodiments are provided in which the monofilaments each have a tensile strength of 3500 MPa to 3700 MPa, preferably in which a force of 285 N to 325 N must be applied for an elongation of 1%.

[0026] Monofilaments having such tensile strengths exhibit advantageously high breaking strengths.Tensile strength and force at 1% elongation are measured according to ASTM D 2969.

[0027] Advantageous embodiments are provided in which the strength member layer has a steel weight fraction of 47% by weight to 63.5% by weight, preferably 48.9% by weight to 62.3% by weight, particularly preferably 52% by weight to 58% by weight, and in which the strength member layer has a spacing factor S of 2.00 to 2.67, preferably 2.05 to 2.57, particularly preferably 2.10 to 2.50.

[0028] In the context of the present invention, the spacing factor S is defined as:

[0029] S = 1 + ((y + y' + x) / (2 × d)),

[0030] Wherein, y is the thickness of the strength member layer on the first side of the monofilament of the strength member layer, y' is the thickness of the strength member layer on the opposite second side of the monofilament, the above thicknesses are measured perpendicular to the area extent of the strength member layer in each case, x is the spacing between the monofilament and the adjacent monofilament of the strength member layer, and d is the diameter of the monofilament. y and y' are measures of the rubberized thickness of the strength member layer above and below the cord, wherein y+y'+d is the total thickness of the strength member layer measured perpendicular to the area extent of the strength member layer. In addition, d+x defines the repeat spacing (pitch) of the monofilaments.

[0031] The spacing factor S takes into account the sheathing of the monofilaments with the rubber material of the strength member layer. The spacing factor S characterizes the strength member layer, in particular with regard to the probability of crack propagation and the absorption of shear forces.

[0032] High linear density of 92g / 100m to 105g / 100m of monofilament together with 98mm of strength member layer per meter of monofilament 2 Up to 125mm 2The high cross-sectional area of ​​47% by weight to 63.5% by weight, preferably 48.9% by weight to 62.3% by weight, particularly preferably 52% by weight to 58% by weight of steel in the strength member layer makes it possible to achieve a strength member layer which is advantageous in terms of layer thickness and layer weight and in terms of rolling resistance and is particularly suitable as a belt layer. With respect to a spacing factor S of 2.00 to 2.67, preferably 2.05 to 2.57, particularly preferably 2.10 to 2.50, which further characterizes the sheathing of the monofilaments with rubber material and allows for an advantageous absorption of shear forces by the sheathing rubber material, and an elongation at break of 300% to 450% for the sheathing rubber material, the strength member layer configured in this way also exhibits reduced crack formation and crack propagation, thereby further improving the durability of the strength member layer.

[0033] Advantageous embodiments are provided in which the monofilaments have no twist around their axis.

[0034] This enables a stable coating process of the strength member with the rubber material. This simultaneously facilitates the orientation and uniform distribution of the monofilaments within the strength member layer. It is preferred that the strength member layer comprises the same amount of rubber material above and below the strength member.

[0035] Advantageous embodiments are provided in which the monofilaments have a twist angle of not more than 10°, preferably not more than 1°.

[0036] Such a low twist angle of not more than 10° has only a minor effect on the properties of the monofilaments. Such a low twist enables a stable coating process of the strength component with the rubber material. A twist angle of not more than 1° is particularly advantageous. This simultaneously helps the orientation and uniform distribution of the monofilaments within the strength component layer.

[0037] The twist angle is calculated as atan (π×d / P)×180 / π, where d is the diameter of the monofilament and P is the twist pitch (pitch). To this end, the monofilament can be analyzed using an optical microscope. In this case, the diameter d (in millimeters) and the value corresponding to half the twist pitch P (in millimeters) can be determined. This value is determined using a drawing mark on the surface of the monofilament. This value is multiplied by 2 to obtain the twist pitch P.

[0038] It is preferred that the strength member layer comprises the same amount of rubber material above and below the strength member.

[0039] An advantageous embodiment is provided in which the rubber material has a resistance of 15 N / mm 2 Up to 22N / mm 2 tensile strength.

[0040] The tensile strength of the rubber material is measured at room temperature in accordance with DIN 53504. Such a tensile strength allows a favourable compromise between the service life of the strength component layers of the tire, in particular the belt layers, and the rolling resistance properties.

[0041] An advantageous embodiment is provided in which the rubber material has a Shore hardness of 77 to 81 (Shore A).

[0042] The Shore hardness of the rubber material is measured at room temperature in accordance with DIN 53505. Such a Shore hardness allows a favourable compromise between the service life of the strength component layers of the tire, in particular the belt layers, and the rolling resistance properties.

[0043] An advantageous embodiment is provided in which the rubber material has a rebound resilience of 38 to 45%.

[0044] The resilience of the rubber material is measured at room temperature in accordance with DIN 53512. Such a resilience allows a favourable compromise between the service life of the strength component layers of the tire, in particular the belt layers, and the rolling resistance properties.

[0045] Advantageous embodiments are provided wherein the vehicle pneumatic tyre comprises a belt and wherein the strength member layer is a strength member layer of the belt, preferably wherein the belt comprises two such strength member layers, the strength members of the two strength member layers crossing at an angle of 18° to 45°.

[0046] A vehicle pneumatic tire comprising such a belt, which comprises at least one strength member layer according to the invention as a belt strength member layer, has advantageous durability and handling properties and good rolling resistance. The vehicle pneumatic tire is in particular a tire of radial construction.

[0047] The vehicle tyre comprising a belt arranged according to the invention is preferably a tyre for a passenger car, a light truck or a commercial vehicle. Preferably, it is a passenger car or a light truck.

[0048] Advantageous embodiments are provided in which the vehicle pneumatic tire, in particular a vehicle pneumatic tire of radial construction, comprises a carcass and in which the strength member layer is a strength member layer of the carcass.

[0049] A vehicle pneumatic tire (especially a vehicle pneumatic tire with a radial construction) comprising a carcass (which comprises at least one strength member layer according to the present invention as a carcass strength member layer) has favorable durability characteristics and handling characteristics, as well as good rolling resistance. If it is a vehicle pneumatic tire with a radial construction, the strength members of the carcass strength member layer in the sidewall are arranged at an angle of 0° to 10°, preferably 0° to 8°, relative to the radial direction.

[0050] A vehicle tire, in particular a vehicle tire of radial construction, comprising a carcass configured according to the invention is preferably a tire for a passenger car, a light truck, a commercial vehicle, etc. The tire is particularly preferably a vehicle pneumatic tire for a passenger car. A motor vehicle propelled by an electric motor, in particular such a passenger car, comprising one or more tires according to the invention, particularly benefits from low rolling resistance, as well as improved handling characteristics and improved durability.

[0051] All embodiments of the vehicle pneumatic tire according to the invention reproduced in this specification are examples of configurations of the invention and should be regarded as non-restrictive. Accordingly, further embodiments of the invention as the subject of the invention are also provided by individual features or multiple features of one embodiment alone or in combination with features of different embodiments, unless otherwise explicitly explained in the description. In addition, combinations of preferred embodiments and particularly preferred embodiments can also be combined with each other. DETAILED DESCRIPTION

[0052] An exemplary embodiment of a vehicle pneumatic tire according to the present invention is provided below. Concerned is a vehicle pneumatic tire having a radial construction, the vehicle pneumatic tire having a strength member layer, the strength member layer including strength members made of steel, the strength members being arranged in the strength member layer, substantially parallel and spaced apart from each other and embedded in a rubber material, wherein each of the strength members is configured as a monofilament, wherein the monofilament occupies 98 mm per meter of the strength member layer. 2 Up to 125mm 2 A cross-sectional area of ​​1000 mm / s and wherein the steel has a carbon content of at least 0.86% by weight.

[0053] The tire is characterized 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; the monofilaments each have a linear density of 92 g / 100 m to 105 g / 100 m; the monofilaments each have a tensile density Td of 34 MPa / (g / 100 m) to 39 MPa / (g / 100 m), wherein the tensile density Td is defined as the quotient of the tensile strength of the strength member and the linear density; the strength member layer has a strength of 109 Nmm 2 Up to 166Nmm 2 The area strength AS is defined as the product of the breaking strength and diameter of a single filament of the strength member layer and the spacing between the single filament and adjacent single filaments of the strength member layer; and the rubber material has a breaking elongation of 300% to 450%.

[0054] The monofilaments may have a compression modulus of 138 GPa to 155 GPa, a compression displacement of 0.95% to 1.05% and / or a compression stress of 1400 MPa to 1500 MPa. The monofilaments may have in each case 270 Nmm 2 Up to 340Nmm 2 The monofilaments may each have a tensile strength of 3500 MPa to 3700 MPa, and preferably a force of 285 N to 325 N must be applied for 1% elongation.

[0055] The strength component layer can have a steel weight fraction of 47% by weight to 63.5% by weight, preferably 48.9% by weight to 62.3% by weight, particularly preferably 52% by weight to 58% by weight, wherein the strength component layer has a spacing factor S of 2.00 to 2.67, preferably 2.05 to 2.57, particularly preferably 2.10 to 2.50.

[0056] The monofilaments may have a twist angle of not more than 10°, preferably not more than 1°. The monofilaments may have no twist around their own axis.

[0057] The rubber material of the strength member layer may have a strength of 15 N / mm 2 Up to 22N / mm 2 The rubber material of the strength member layer may have a Shore hardness of 77 to 81 (Shore A). The rubber material of the strength member layer may have a rebound resilience of 38 to 45.

[0058] Such a pneumatic vehicle tire is particularly advantageous if the strength member layer is a belt layer. More advantageously, two belt layers crossing at an angle of 18° to 45° are arranged in this manner. However, the strength member layer may also be a carcass layer of a pneumatic vehicle tire.

[0059] Tire tests were conducted to determine the tire durability of tires. The tires involved were pneumatic vehicle tires of radial construction with two belt layers in each case, size 175 / 65R15. The belt layers were configured as strength member layers, which included strength members made of steel, which were arranged in the respective strength member layers, substantially parallel to each other and spaced apart and embedded in the rubber material. The strength members of the two belt layers of the respective tire crossed at an angle of 18° to 45°.

[0060] Comparative tires not according to the invention (reference tire 1, reference tire 2) and tires according to the invention (example tires) were tested. Reference tire 1, reference tire 2 and example tire differ from one another only in the configuration of their belts.

[0061] Table 1 lists the parameters of the belt layers / strength members (FT) of the belt layers of Reference Tire 1, Reference Tire 2 and the example tires of the present invention.

[0062] Table 2 provides a comparative evaluation of the properties of the tires tested.

[0063] The belt layers of the exemplary tires of the invention listed in Table 1 comprise monofilaments as strength members, wherein the steel has a carbon content of at least 0.86% by weight. The monofilaments have a twist angle of not more than 1°. The monofilaments in particular have no twist around their axis. The strength member layer in particular has a steel weight fraction of 57.8% and a spacing factor S of 2.19.

[0064] The belt layers of the reference tire 1 listed in Table 1 comprised as strength members conventional steel cords of x2 configuration with a lay length of 14 mm. The steel had a carbon content of less than 0.86% by weight.

[0065] The belt layers of the reference tire 2 listed in Table 1 comprise steel filaments as strength members having a lower linear density than the filaments of the example layers, wherein the steel likewise has a carbon content of at least 0.86% by weight. The filaments have a twist angle of not more than 1°. The filaments in particular have no twist about their axis.

[0066] The strength members of the belt layers of the test tires each had 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 rubber material of the belt layers each had an elongation at break of 300% to 450%.

[0067] The tensile strength and the force at 1% elongation and the breaking strength of the corresponding strength members were measured according to ASTM D2969.

[0068] The elongation at break of the rubber material is measured at room temperature according to DIN 53504. The tensile strength of the rubber material is measured at room temperature according to DIN 53504. The Shore hardness of the rubber material is measured at room temperature according to DIN 53505. The resilience of the rubber material is measured at room temperature according to DIN 53512.

[0069] In order to determine the compression modulus, the compression displacement and the compression stress, a sample of a rubber cylinder (in particular a rubber cylinder consisting of the same rubber material as the rubber material of the strength member layer) comprising a steel strength member arranged along the axis of rotation of the cylinder is tested in comparison with a sample consisting of a corresponding rubber cylinder without such a strength member. The corresponding cylinder has a diameter of 15 mm and a length of 25 mm, and the test is carried out at room temperature with a preload of 2 N and a test speed of 5 mm / min. In order to determine the compression characteristics of the strength member, the difference between the two samples with and without the strength member is taken into account.

[0070] The out-of-plane bending stiffness of the corresponding strength member is measured by means of the customary 3-point bending test. In this case, the bending stiffness of the steel strength member is determined due to the forces acting on the strength member perpendicularly to the extension direction of the strength member. In this case, linear pieces of steel strength members are tested, wherein the test length and the distance between the two contact points at which the strength member is supported depend on the linear density of the strength member. The bending strength of the example monofilaments was measured at a test length of 50.02 mm, a distance between the two contact points of 20.02 mm, a speed of 2.503 mm / s and a preload of 0.03 N.

[0071] The twist angle is calculated as atan (π×d / P)×180 / π, where d is the diameter of the monofilament and P is the twist pitch (pitch). To this end, the monofilament is analyzed using an optical microscope. In this case, the diameter d (in millimeters) and the value corresponding to half the twist pitch P (in millimeters) are determined. This value is determined using a drawing mark on the surface of the monofilament. This value is multiplied by 2 to obtain the twist pitch P.

[0072] Reference tire 1 Reference tire 2 Example tire Number of filaments per strength member (FT) 2 1 1 Twist length [mm] (FT) 14 - - <![CDATA[Cross-sectional area FTL of the strength member per meter [mm 2 > 134.3 115.5 119.4 Linear density [g / 100m] (FT) 112 75 99 Tensile density Td[MPa / (g / 100m)](FT) 28.6 49.3 36.4 <![CDATA[Area intensity AS [Nmm 2 > 120 60 116 Breaking strength [N] (FT) 445 355 445 Compression modulus [GPa] (FT) 128 145 151 Compression displacement [%] (FT) 0.80 0.90 0.97 <![CDATA[Compressive stress [N / mm 2 (FT)]]> 922 1384 1468 <![CDATA[Out-of-plane bending stiffness of FT [Nmm 2 > 200 195 330 Force at 1% elongation [N] 320 232 300 Tensile strength[MPa](FT) 3200 3700 3600

[0073] Table 1

[0074] Table 2 provides a comparative evaluation of the properties of the tires tested.

[0075]

[0076] Table 2

[0077] The determined tire durability of reference tire 1 is rated as 100%. Obviously, reference tire 2 has a lower tire durability than reference tire 1. In contrast, the example tire of the present invention has a tire durability comparable to that of reference tire 1. The crucial point is that the tire durability is improved compared to reference tire 2, which includes steel monofilaments similar to the example tire of the present invention. This is made possible by the reduced tensile density Td and higher area strength AS compared to reference tire 2, as well as the increased linear density and still high elongation at break of the rubber material of the example tire of the present invention.

[0078] At the same time, the linear density of the monofilaments and the cross-sectional area of ​​the strength members per meter of the strength member layer of the example tire and the reference tire 2 are significantly reduced compared to the reference tire 1, thereby enabling a rolling resistance that is still advantageously reduced in each case compared to the reference tire 1.

[0079] As indicated in Table 2, the determination of the handling characteristics of the test tires shows the advantages of the example tires of the invention, in particular compared with reference tire 2. Here too, the increased linear density has proven to be advantageous.

[0080] The increased values ​​of compression modulus, compression displacement and compression stress, as well as the significantly increased out-of-plane bending stiffness have proven to be favorable for the continued favorable rolling resistance, greater robustness and improved handling characteristics of the example tires of the invention compared to reference tire 2. The increased force at 1% elongation, as well as the only slight reduction in tensile strength, have likewise proven to be favorable.

Claims

1. A vehicle pneumatic tire, in particular a vehicle pneumatic tire of radial construction, having a strength member layer, the strength member layer comprising strength members made of steel, which are arranged in the strength member layer, are substantially parallel to each other and are spaced apart and are embedded in a rubber material, in, Each of these strength members is configured as a monofilament, Among them, these monofilaments occupy 98mm per meter of strength member layer 2 Up to 125mm 2 The cross-sectional area of wherein the steel has a carbon content of at least 0.86% by weight, It is characterized in that These 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 / 100 m to 105 g / 100 m, These monofilaments have a tensile density Td of 34 MPa / (g / 100 m) to 39 MPa / (g / 100 m), wherein The tensile density Td is defined as the quotient of the tensile strength and the linear density of the corresponding strength member, ●The strength member layer has 109Nmm 2 Up to 166Nmm 2 The area strength AS is defined as the product of the breaking strength and the diameter d of the single filament of the strength member layer and the spacing x between the single filament and the adjacent single filament of the strength member layer, The rubber material has an elongation at break of 300% to 450%.

2. The vehicle pneumatic tire according to claim 1, wherein: These 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. Pneumatic vehicle tire according to one or more of the preceding claims, characterized in that These monofilaments each have a 270 Nmm 2 Up to 340Nmm 2 Out-of-plane bending stiffness.

4. Pneumatic vehicle tire according to one or more of the preceding claims, characterized in that These monofilaments each have a tensile strength of 3500 to 3700 MPa; preferably, a force of 285 to 325 N must be applied for an elongation of 1%.

5. Pneumatic vehicle tire according to one or more of the preceding claims, characterized in that The strength member layer has a weight fraction of steel of 47% by weight to 63.5% by weight, preferably 48.9% by weight to 62.3% by weight, particularly preferably 52% by weight to 58% by weight, and The strength member layer has a spacing factor S of 2.00 to 2.67, preferably 2.05 to 2.57, particularly preferably 2.10 to 2.50, where S=1+((y+y'+x) / (2×d)), where y is the thickness of the strength member layer on a first side of a monofilament of the strength member layer, y' is the thickness of the strength member layer on the opposite second side of the monofilament, x is the spacing between the monofilament and an adjacent monofilament of the strength member layer, and d is the diameter of the monofilament.

6. Pneumatic vehicle tire according to one or more of the preceding claims, characterized in that The monofilaments have no twist about their axis.

7. Pneumatic vehicle tire according to one or more of the preceding claims, characterized in that The monofilaments have a twist angle of not more than 10°, preferably not more than 1°.

8. Pneumatic vehicle tire according to one or more of the preceding claims, characterized in that The rubber material has a 15N / mm 2 Up to 22N / mm 2 tensile strength.

9. Pneumatic vehicle tire according to one or more of the preceding claims, characterized in that The rubber material has a Shore hardness of 77 to 81 (Shore A).

10. Pneumatic vehicle tire according to one or more of the preceding claims, characterized in that The rubber material has a rebound resilience of 38 to 45.

11. Pneumatic vehicle tire according to one or more of the preceding claims, characterized in that The vehicle pneumatic tire, in particular a vehicle pneumatic tire with a radial construction, comprises a belt; and the strength member layer is a strength member layer of the belt; preferably, the belt comprises two such strength member layers, the strength members of the two strength member layers cross at an angle of 18° to 45°.

12. Pneumatic vehicle tire according to one or more of the preceding claims, characterized in that The vehicle pneumatic tire, in particular, a vehicle pneumatic tire having a radial construction includes a carcass; and the strength member layer is a strength member layer of the carcass.

Images