Pneumatic vehicle tire

Abstract

The invention relates to a pneumatic vehicle tire comprising a profiled tread (1), a belt assembly (2), a carcass insert (6), lateral walls (3), horn profiles (8), and at least one discharge path (9, 10, 11, 12, 13) for discharging electrostatic charges, wherein the discharge path (9, 10, 11, 12, 13) comprises a first electrically conductive sub-passage (9) which passes through the tread (1) in the radial direction, a second electrically conductive sub-passage (10) which adjoins the first sub-passage and runs on the inner face of the tread (1), and a third electrically conductive sub-passage (11) which adjoins the second electrically conductive sub-passage (10), runs on the inner face of the lateral wall (3), and contacts the adjoining horn profile (8). The electrically conductive sub-passages (9, 10, 11) of the discharge path (9, 10, 11) are vulcanized electrically conductive layers (9, 10, 11), each of which has a thickness of maximally 0.10 mm.

Description

[0001] Description

[0002] Pneumatic vehicle tires

[0003] The invention relates to a pneumatic vehicle tire with a profiled tread, a belt assembly, a carcass ply, sidewalls and horn profiles and at least one discharge path for discharging electrostatic charges, wherein the discharge path comprises a first electrically conductive partial passage penetrating the tread in the radial direction, a second electrically conductive partial passage adjoining the first and running on the inside of the tread, and a third electrically conductive partial passage adjoining the second electrically conductive partial passage, running on the inside of the sidewall and contacting the adjacent horn profile.

[0004] Such a pneumatic vehicle tire is known, for example, from

[0005] DE 602005 004481 T2. The tire has a conduction path formed by a rubber strip extending radially through the tread, a band-shaped, electrically conductive rubber layer running along the inside of the tread, and another band-shaped, electrically conductive rubber layer running in the area of ​​the sidewall. The rubber layers can each be formed by applying a rubber solution. The resulting conduction path allows corresponding tire components to be manufactured from silica-containing rubber compounds, thereby reducing rolling resistance.

[0006] Legal requirements make it necessary to find further measures to further reduce the rolling resistance of pneumatic vehicle tires. The invention is therefore based on the object of further improving a pneumatic vehicle tire of the type mentioned above with regard to rolling resistance while maintaining the required dissipation path.

[0007] The object is achieved according to the invention in that the electrically conductive partial passages of the discharge path are vulcanized, electrically conductive layers each with a thickness of at most 0.10 mm.

[0008] The electrically conductive structure (discharge path) implemented in the tire is therefore formed from particularly thin layers over its entire extent, which further reduces the amount of electrically conductive material required and thus the rolling resistance.

[0009] According to a preferred embodiment, the electrically conductive layer, which is the third electrically conductive partial passage, extends to the bead base of the horn profile, wherein the horn profile is preferably made of electrically non-conductive rubber material. This contributes to a further reduction in rolling resistance.

[0010] According to a first preferred variant of the latter embodiment, the electrically conductive layer, which is the third electrically conductive partial passage, has an end section penetrating the flange profile, which exits at the bead base of the flange profile or ends at an additional, vulcanized, electrically conductive layer formed on the bead base and belonging to the dissipation path, which has a width of up to 5.0 mm in the axial direction. This ensures a particularly short dissipation path. The additional electrically conductive layer improves contact with the rim.

[0011] According to a second preferred variant of the latter embodiment, the electrically conductive layer, which is the third electrically conductive partial passage, extends in sections between the horn profile and the inner layer, as well as across the inner side of the outer surface of the horn profile, adjacent to the inner layer, to the bead toe, and preferably also further to the bead base of the outer surface of the horn profile. This eliminates the need for the end section of the third electrically conductive partial passage penetrating the horn profile, which allows for particularly simple production of the discharge path.

[0012] According to a further preferred embodiment, the electrically conductive layer, which is the second electrically conductive partial passage, is vulcanized into the tread on the inside of the tread. Such a layer is easy to manufacture.

[0013] In a further preferred embodiment, the electrically conductive layer, which is the third electrically conductive partial passage, is vulcanized into the inside of the sidewall and preferably into the inside of the horn profile. Such a layer is also easy to manufacture.

[0014] According to a further preferred embodiment, the radially outer end of the layer, which is the first electrically conductive partial passage, is adjoined by an additional layer located on the outer surface of the tread, vulcanized into the tread, and belonging to the dissipation path. This additional layer has a width of, in particular, up to 5.0 mm in the axial direction. This additional layer contributes to improving the contact of the dissipation path with the ground in new or slightly worn tires.

[0015] For the rolling resistance of the pneumatic vehicle tire, it is advantageous if the tread, the rubber lining of the belt layers of the belt assembly, the sidewalls, the carcass rubber lining of the carcass insert, the inner layer, and the horn profiles are made of electrically non-conductive rubber material. Further features, advantages, and details of the invention will now be explained in more detail with reference to the single figure, Fig. 1, which schematically shows a partial cross-section of a pneumatic vehicle tire.

[0016] Pneumatic vehicle tires designed according to the invention are tires for motor vehicles, in particular for multi-track motor vehicles, preferably for passenger cars (PCs), vans (transporters), SLIVs or commercial vehicles, and preferably tires of radial design for rims with a rim diameter of 13 inches to 24 inches, in particular of 18 inches to 23 inches.

[0017] Fig. 1 shows one half of a cross-section of a pneumatic vehicle tire, which is a passenger car tire, with a profiled tread 1, a two-ply belt assembly 2, sidewalls 3, bead areas each with a bead core 4 and a bead filler 5, a carcass ply 6, an airtight inner layer 7 and horn profiles 8. The tire equatorial plane is marked by a line AA.

[0018] As will be explained in more detail below, the pneumatic vehicle tire has at least one discharge path to conduct the electrostatic charges generated during driving from the vehicle, in particular from the body, to the respective ground ("grounding"). In the case of pneumatic vehicle tires mounted on a rim, the discharge path contacts the rim. The entire discharge path is formed exclusively from mutually contacting, electrically conductive layers 9, 10, 11, 12, 13, each with a maximum thickness of 0.10 mm. The layers 9, 10, 11, 12, 13 are formed during the vulcanization process from an electrically conductive suspension previously applied to the respective tire components, as will be explained in more detail below.

[0019] The electrically conductive suspension is based, for example, on latex or a mineral oil plasticizer, in each case in combination with electrically conductive particles, such as soot particles, graphite powder, carbon nanotubes or particles from an electrically conductive rubber mixture, i.e. particles obtained by comminuting an electrically conductive rubber mixture. The proportion of electrically conductive particles in the suspension is, for example, 10 wt.% to 70 wt.%, in particular 30 wt.% to 50 wt.%. The amounts of the constituents of the suspension are coordinated such that the suspension preferably has a dynamic viscosity at 20°C of 1.0 Pa s to 100.0 Pa s, in particular of up to 50.0 Pa s, and preferably of up to 20.0 Pa s.

[0020] A suspension based on mineral oil plasticizer contains, for example, the following components: a) Mineral oil plasticizer: o 300 phr to 800 phr, preferably 500 phr to 700 phr, whereby the mineral oil plasticizer(s) preferably have the following hydrocarbon contents according to ASTM D 2140 - 08 (2017) (Note: The hydrocarbon contents are known to be determined from an empirical function composed of the viscosity-density relationship and the refractive index):

[0021] ■ Aromatic hydrocarbon content CA = 0% to 5%

[0022] ■ Paraffinic hydrocarbon content cp = 50% to 85%

[0023] ■ Naphthenic hydrocarbon content CN = 15% to 50% b) Diene rubber(s): o 100 phr, preferably:

[0024] ■ 70 phr to 100 phr, preferably up to 80 phr, synthetic polyisoprene (IR) and / or natural rubber and / or

[0025] ■ 0 phr to 30 phr of further diene rubber, for example polybutadiene (BR), preferably vinyl-containing polybutadiene, styrene-butadiene rubber (SBR), ethylene-propylene-diene rubber (EPDM), chloroprene rubber (CR), acrylonitrile-butadiene rubber (NBR). c) Zinc oxide: 1.0 phr to 5.0 phr, in particular 2.0 phr to 4.0 phr, o preferably nanostructured zinc oxide. d) Sulfur: 1.0 phr to 4.0 phr. e) Accelerators: 1.0 phr to 6.0 phr, o in particular thiazoles and / or sulfenamides, preferably exclusively sulfenamides. f) Stearic acid: 1.0 phr to 6.0 phr. g) Carbon black: 40 phr to 110 phr, in particular 50 phr to 100 phr, preferably up to 80 phr, o in particular beaded carbon black and / or fluffy carbon black, for example Printex® XE2-B (from Orion Engineered Carbos, BET surface area according to ASTM D 6556: 1000 m 2 / g, DBP number according to ASTM D 2414: 420 ml / 100 g), N 326, N 339 or N 121.

[0026] The sulfur can come from a sulfur donor system without accelerator activity, for example, 4,4'-dithiodimorpholine (DTDM). Furthermore, the sulfur and accelerator can come from a sulfur donor system with accelerator activity, for example, tetramethylthiuram disulfide (TMTD).

[0027] Table 1 shows exemplary compositions of a mineral oil plasticizer-based suspension. The intended high-molecular-weight polyisoprene, as is known, has a higher molecular weight than the liquid polyisoprene contained therein.

[0028] Table 1 : Composition of the suspension

[0029] The tread 1 in the exemplary embodiment has a single layer construction, but can also be constructed in multiple layers in the radial direction, contains a profile, has an outer surface 1a located in the tread periphery and is made of electrically non-conductive rubber material. The tread 1 is interspersed in the region of the tire equatorial plane in the radial direction by an electrically conductive layer 9. The layer 9 can run circumferentially or be distributed over the circumference in points or sections and thus forms a single-part or multi-part, electrically conductive partial passage. If the electrically conductive partial passage is multi-part, it is designed such that when the tire rolls, at least a part of the electrically conductive partial passage is located in the ground contact area.The ground contact area corresponds, as is known, to the statically determined footprint (determined with a tire mounted on a standard rim, loaded at 70% of the maximum load capacity, internal pressure at 85% of the standard pressure, according to ETRTO standards). In the exemplary embodiment, the radially outer end of layer 9 is adjoined by a layer 12 vulcanized into the outer surface 1a of the tread 1, which has a width of up to 5.0 mm in the axial direction.

[0030] To form the tread 1, a green tread, which subsequently forms the tread 1, is extruded from a rubber mixture (single-piece tread) or from several rubber mixtures (multi-piece tread). The green tread is cut into two green tread pieces, and an electrically conductive suspension is applied to at least one of the cut surfaces, at least in sections, over the entire height of the cut surface, to form layer 9. At the same time, an electrically conductive suspension is applied to form layer 12. The green tread pieces are then joined together. Alternatively, the green tread pieces can be extruded separately, with the electrically conductive suspension being applied to at least one of the surfaces over which the green tread pieces are joined, at least in sections, over the entire height of the surface, to form layer 9.Furthermore, in this variant, electrically conductive suspension is also applied to form layer 12.

[0031] The belt assembly 2 consists of a radially inner belt layer 2a and a radially outer belt layer 2b. The belt layers 2a, 2b each consist of reinforcements, for example made of steel or textile cords of known construction, embedded in an electrically non-conductive belt rubber coating and running parallel to one another in each belt layer 2a, 2b. The reinforcements of the radially inner belt layer 2a intersect those of the radially outer belt layer 2b in a particularly known manner. The belt layers 2a, 2b can be covered with a belt bandage consisting of reinforcements, generally textile, preferably made of nylon or polyester, embedded in an electrically non-conductive bandage rubber coating.

[0032] Between the tread 1 and the belt assembly 2 there runs an electrically conductive layer 10 which is formed on the inside of the tread 1 and vulcanized into it, which electrically conductive layer 10 contacts the electrically conductive layer 9, runs from the layer 9 over one tread half in the direction of the tire shoulder and forms a second electrically conductive partial passage.

[0033] To form the layer 10, the electrically conductive suspension is applied to that side of the green tread or one green tread half which forms or co-forms the inside of the tread 1 in the pneumatic vehicle tire in such a way that it contacts the suspension applied to the cut surfaces of the green tread parts.

[0034] The sidewalls 3 are made of an electrically non-conductive rubber material and overlap the horn profiles 8 on the outside of the tire. The carcass ply 6 runs in a conventional manner between the belt assembly 2 and the inner layer 7, as well as between the sidewalls 3 and the inner layer 7, and is folded around the bead cores 4 from the inside outward, forming carcass turnups 6a. The carcass ply 6 consists of an electrically non-conductive carcass rubber lining and reinforcements embedded therein.

[0035] The inner layer 7 consists of an electrically non-conductive rubber material and is designed in a manner known per se.

[0036] The horn profiles 8 are also made of an electrically non-conductive rubber material and each have an outer surface 8a extending between the inner layer 7 and the respective side wall 3, which outer surface 8a is composed of an inner side 8ai extending towards the inner layer 7, a bead sole 8a2, a bead heel 8as, and an outer side 8a4 extending towards the corresponding side wall 3, wherein the inner side 8ai and the bead sole 8a2 are connected to one another via a bead toe 8as. The bead sole 8a2, viewed in cross-section, is straight or, viewed in cross-section, is composed of several straight sections. The bead heel 8as, viewed in cross-section, is curved outwards (arched) at least over a section immediately adjacent to the bead sole 8a2 and, in particular, is continuously curved outwards.

[0037] An electrically conductive layer 11 is formed in the sidewall area, which runs between the sidewall 3 and the carcass ply 6 and between the horn profile 8 and the apex 5 or between the horn profile 8 and the carcass turn-up 6a. The layer 11 contacts the layer 10 and penetrates the horn profile 8 with an end section 11a in such a way that the layer 11, i.e. the end section 11a, emerges from the bead sole 8a2 or, as shown in the exemplary embodiment, ends at a layer 13 formed on the bead sole 8a2. The layer 11 forms a third electrically conductive partial passage, is vulcanized into the sidewall 3 and the horn profile 8 and is formed - with the exception of the end section 11a - on the inner sides of the sidewall 3 and the horn profile 8. The layer 13 is vulcanized into the horn profile 8 and has a width of up to 5.0 mm in the axial direction.

[0038] To form layer 11, an electrically conductive suspension is applied to the side of the coextruded sidewall / flange profile that forms or co-forms the inside of the sidewall 3 or the flange profile 8 in the pneumatic vehicle tire. To create the end section 11a, the extruded flange profile is cut open, an electrically conductive suspension is applied, and the flange profile is reassembled. To form layer 13, an electrically conductive suspension is applied to the reassembled flange profile at the corresponding location.

[0039] In the described embodiment, the tread 1, the rubber lining of the belt layers 2a, 2b, the sidewall 3, the carcass rubber lining of the carcass insert 6, the inner layer 7, and the horn profiles 8 are made of electrically non-conductive rubber material. The rubber compounds underlying these components therefore contain correspondingly large amounts of silica. As is well known, this measure is beneficial for the tire's rolling resistance as well as for the cut and crack resistance of the respective tire component.

[0040] The terms “electrically conductive particles”, “electrically conductive rubber material”, “electrically conductive layers” and “electrically conductive partial passages” are understood to mean those which have a specific electrical resistance of < 10 8 Ohm cm or has.

[0041] The invention is not limited to the described embodiment.

[0042] Layers 12 and 13 are optional. The electrically conductive layer 11 does not have to traverse the horn profile 8, but can extend between the horn profile 8 and the inner layer 7 and then over the inner side 8ai of the outer surface 8a of the horn profile 8 to the bead toe 8as and optionally further to the bead sole 8a2.

[0043] The end section 11a is omitted in this embodiment. Furthermore, the horn profile 8 can be made of electrically conductive rubber material, with the layer 11 ending at any point in contact with the horn profile 8, thus forming part of the discharge path.

[0044] List of reference symbols

[0045] 1 tread

[0046] 1a Outer surface 2 Belt bandage

[0047] 2a radial inner belt layer

[0048] 2b radial outer belt layer

[0049] 3 side wall

[0050] 4 Bead core 5 Bead filler

[0051] 6 Carcass insert

[0052] 6a Carcass roll

[0053] 7 inner layer

[0054] 8 Horn profile 8a Outer surface

[0055] 8ai inside

[0056] 8a2 Bead sole

[0057] 8as bead heel

[0058] 8a4 outside 8as bead toe

[0059] 9 layer

[0060] 10 layers

[0061] 11 shift

[0062] 11a End section 12 layer

[0063] 13 shift

[0064] AA line (tyre equatorial plane)

Claims

Patent claims 1. Pneumatic vehicle tire with a profiled tread (1), a belt assembly (2), a carcass insert (6), sidewalls (3) and horn profiles (8) and at least one discharge path (9, 10, 11, 12, 13) for dissipating electrostatic charges, wherein the discharge path (9, 10, 11, 12, 13) comprises a first electrically conductive partial passage (9) penetrating the tread (1) in the radial direction, a second electrically conductive partial passage (10) adjoining the first electrically conductive partial passage and running on the inside of the tread (1), and a third electrically conductive partial passage (11) adjoining the second electrically conductive partial passage (10), running on the inside of the sidewall (3) and contacting the adjacent horn profile (8), characterized in that the electrically conductive partial passages (9, 10, 11) of the Discharge path (9, 10, 11) are vulcanized, electrically conductive layers (9, 10, 11) each with a thickness of at most 0.10 mm.

2. Pneumatic vehicle tire according to claim 1, characterized in that the electrically conductive layer (11), which is the third electrically conductive partial passage (11), runs to the bead base (8a2) of the horn profile (8), wherein the horn profile (8) preferably consists of electrically non-conductive rubber material.

3. Pneumatic vehicle tire according to claim 2, characterized in that the electrically conductive layer (11), which is the third electrically conductive partial passage (11), has an end section (11a) which penetrates the horn profile (8) and which emerges at the bead base (8a2) of the horn profile (8) or ends at an additional, vulcanized, electrically conductive layer (13) formed on the bead base (8a2) and belonging to the discharge path (9, 10, 11, 12, 13), which has a width of in particular up to 5.0 mm in the axial direction.

4. Pneumatic vehicle tire according to claim 2, characterized in that the electrically conductive layer (11), which is the third electrically conductive partial passage (11), runs in sections between the horn profile (8) and the inner layer (7) and over the inner side (8ai) of the outer surface (8a) of the horn profile (8) adjoining the inner layer (7) to the bead toe (8as) and preferably additionally further to the bead sole (8a?) of the outer surface (8a) of the horn profile (8).

5. Pneumatic vehicle tire according to one of claims 1 to 4, characterized in that the electrically conductive layer (10), which is the second electrically conductive partial passage (10), is vulcanized into the tread (1) on the inside of the tread (1).

6. Pneumatic vehicle tire according to one of claims 1 to 5, characterized in that the electrically conductive layer (11), which is the third electrically conductive partial passage (11), is vulcanized into the inside of the side wall (3) and preferably into the inside of the horn profile (8).

7. Pneumatic vehicle tire according to one of claims 1 to 6, characterized in that an additional layer (12) lying on the outer surface (1a) of the tread (1), vulcanized into the tread (1), belonging to the discharge path (9, 10, 11, 12, 13) adjoins the radially outer end of the layer (9), which is the first electrically conductive partial passage (9), which additional layer (12) has a width of in particular up to 5.0 mm in the axial direction.

8. Pneumatic vehicle tire according to one of claims 1 to 7, characterized in that the tread (1), the belt rubber coating of the belt layers (2a, 2b) of the belt assembly (2), the side walls (3), the carcass rubber coating of the carcass insert (6), the inner layer (7) and the horn profiles (8) consist of electrically non-conductive rubber material.

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