vehicle tires

Abstract

The invention relates to a vehicle tire with a tread (1) made of electrically non-conductive rubber material, a belt assembly (2) with belt layers (2a, 2b) with an electrically non-conductive belt rubber coating, a belt bandage (3) covering the belt layers (2a, 2b) at the edges in the tire cross-section and having an electrically conductive bandage rubber coating, at least one electrically conductive element (7) penetrating the tread (1) in the radial direction and contacting the belt bandage (3), and at least one electrically conductive sidewall / horn profile passage (5) formed in a sidewall region and contacting the belt bandage (3). The tread (1) has at least a profile depth (T UR ) circumferential groove (8) with a maximum width (B UR), wherein the discharge path comprises an electrically conductive material strip (9) installed radially within the circumferential groove (8) between the tread (1) and the belt bandage (3) and associated with the circumferential groove (8), which, viewed in the tire cross-section, has a width (b 1 ) from 130% to 200% of the maximum width (B UR ) of the circumferential groove (8).

Description

[0001] The invention relates to a vehicle tire with a profiled tread made of electrically non-conductive rubber material, a belt assembly with at least two belt layers with an electrically non-conductive belt rubber coating, a belt bandage covering the belt layers at the edges in the tire cross-section and having an electrically conductive bandage rubber coating, at least one electrically conductive element penetrating the tread in the radial direction and contacting the belt bandage, and at least one electrically conductive sidewall / flange profile passage formed in a sidewall region and contacting the belt bandage, which passage is in electrically conductive connection with the rim when the vehicle tire is mounted on the rim, wherein a discharge path for discharging electrostatic charges is formed, which discharge path connects the sidewall / flange profile passage, the belt bandage and thewhich comprises electrically conductive element(s), and wherein an electrically conductive material is one which has a specific electrical resistance of ≤ 10. 8 Ohm cm.

[0002] Such a vehicle tire is known, for example, from EP 3 680 114 A1. This vehicle tire has a profiled tread made of an electrically non-conductive rubber material, a belt assembly with belt layers with an electrically non-conductive belt rubber coating, a belt bandage with an electrically conductive bandage rubber coating, a carcass ply with an electrically conductive carcass rubber coating, an electrically conductive element penetrating the tread in the radial direction, and sidewalls made of electrically non-conductive rubber material. The vehicle tire also has a SUB construction such that radially outer wall sections of the sidewalls extend between the edge section of the radially inner belt ply that does not contact the carcass ply and the carcass ply.In at least one tire shoulder, between the radially outer wall section of the sidewall and the edge section of the radially inner belt layer, at least one electrically conductive rubber strip is installed, which contacts the free end of the belt bandage and the carcass insert.

[0003] It is known that tire components made of electrically non-conductive rubber material, which is based on a rubber mixture containing a large amount of silica, are beneficial with regard to the tire's rolling resistance, and therefore contribute to low rolling resistance. Furthermore, it is known that in order to dissipate electrostatic charges, a discharge path must be provided between the rim and the ground. Legal requirements make it necessary to continually find new measures with which the rolling resistance of vehicle tires can be further reduced. In this case, there is a risk that in vehicle tires of the type mentioned above, the discharge path running via the belt bandage will not be formed in the desired way due to the pressure exerted on the green tire during vulcanization, and this path may subsequently be extended or even interrupted.

[0004] The invention is therefore based on the object of noticeably reducing the risk of an extension or interruption of the discharge path in a vehicle tire of the type mentioned at the beginning.

[0005] The stated object is achieved according to the invention in that the tread has at least one circumferential groove designed to the profile depth and having a maximum width determined on the tread periphery in the axial direction, wherein the discharge path comprises an electrically conductive material strip installed radially within the circumferential groove between the tread and the belt bandage, associated with the circumferential groove, which, viewed in the tire cross-section, has a width determined in the axial direction of 130% to 200% of the maximum width of the circumferential groove.

[0006] According to the invention, an additional, electrically conductive material strip is therefore installed in the groove area subject to particularly high stress during tread formation. This ensures that any local interruption of the conduction path occurring radially within this groove area on the electrically conductive rubber bandage, which occurs due to reinforcements partially protruding from the rubber bandage, i.e., partially exposed, is reliably bridged, thus significantly reducing the risk of a local interruption or an extension of the conduction path.

[0007] According to a preferred embodiment, the width of the electrically conductive material strip is 140% to 190%, in particular 150% to 180%, preferably 160% to 170%, of the maximum width of the circumferential groove. This minimizes the amount of electrically conductive material used, while still ensuring a reliable discharge path.

[0008] A further preferred embodiment provides that the electrically conductive material strip has a thickness of 0.50 mm to 1.50 mm, in particular 0.60 mm to 1.40 mm, preferably 0.70 mm to 1.30 mm, particularly preferably 0.80 mm to 1.20 mm, in the radial direction. This further reduces the risk of interruption of the discharge path due to partially exposed reinforcements.

[0009] Preferably, the electrically conductive material strip, viewed in the tire cross-section, is divided into two strip sections by a central surface of the circumferential groove that bisects the maximum width of the circumferential groove. Each strip section has a width, determined in the axial direction, of 40% to 60%, in particular 45% to 55%, preferably 48% to 52%, of the width of the material strip present in the respective tire cross-section. The material strip therefore runs symmetrically or essentially symmetrically to the respective circumferential groove, which is particularly advantageous with regard to bridging the critical region of the discharge path.

[0010] A further preferred embodiment provides that the electrically conductive material strip runs in the circumferential direction.

[0011] According to a further preferred embodiment, it is provided that the electrically conductive material strip - is an electrically conductive rubber material or at least an electrically conductive thread. - comprises an electrically conductive rubber material or at least one electrically conductive thread, where an electrically conductive thread is one which has an electrical resistance of ≤ 10 6 Ohm per 30 cm of thread length.

[0012] A strip of rubber material or a strip of rubber material is particularly firmly bonded to the adjacent tire components in the fully vulcanized vehicle tire. Electrically conductive threads are particularly lightweight and therefore particularly beneficial with regard to the tire's rolling resistance.

[0013] In the latter embodiment, according to an advantageous further development, the electrically conductive material strip comprises a plurality of electrically conductive threads or is an electrically conductive fabric formed from a plurality of electrically conductive threads.

[0014] Further features, advantages and details of the invention will now be described in more detail with reference to the drawing, which schematically shows an embodiment of the invention. Fig. 1 schematically shows a partial cross-section through a pneumatic vehicle tire with an embodiment of the invention and Fig. 2 an enlarged view of detail Z 2 the Fig. 1.

[0015] Vehicle tires designed according to the invention are tires for passenger cars (PCs), vans (transporters) or SUVs and preferably pneumatic vehicle tires, particularly preferably pneumatic vehicle tires of radial design for rims with an integer rim diameter of 13 inches to 24 inches, in particular of 16 inches to 23 inches.

[0016] Fig. Figure 1 shows a partial cross-section of a pneumatic vehicle tire, which is a passenger car tire. The radial direction is indicated by a double arrow R, the axial direction by a double arrow A, and the tire equatorial plane is indicated by a line AA. The "axial direction" refers to the direction perpendicular to the tire equatorial plane. The "radial direction" refers to the direction parallel to the tire equatorial plane in the axially oriented cross-section.

[0017] The pneumatic vehicle tire has a profiled tread 1, a two-ply belt assembly 2, a belt bandage 3, sidewalls 4, a carcass insert 5, and an inner layer 6. The bead regions (not shown) each have a bead core, a bead filler, and a flange profile made of electrically conductive rubber material and can be designed in a manner known per se.

[0018] The tread 1 has an outer surface 1a located in the tread periphery and a ground contact patch with a width B determined in the axial direction, wherein the ground contact patch 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 85% of the standard pressure, according to ETRTO standards). In the exemplary embodiment, the tread 1 is composed of two tread layers in the radial direction, namely a tread cap 1 containing the tread pattern. 1 and a tread base 1 2 . The Tread Cap 1 1 and the tread base 1 2each consist of an electrically non-conductive rubber material. At least one electrically conductive element 7 is integrated into the tread 1 in the area of ​​the ground contact patch, in the exemplary embodiment in the area of ​​the tire equatorial plane (line AA), which penetrates the tread 1 in the radial direction and extends to the outer surface 1a. In particular, a single electrically conductive element 7 is provided in the form of a so-called carbon center beam, which is an electrically conductive rubber strip running circumferentially. If there are several electrically conductive elements 7, these are preferably distributed over the circumference of the tire in such a way that at least one of the elements 7 is located in the area of ​​the footprint when the tire rolls.

[0019] The tread 1 profile in the embodiment includes four circumferential grooves 8, which are arranged according to Fig. 2 in radial direction to the respective intended profile depth TUR and at the tread periphery, i.e. at the level of the outer surface 1a, in the axial direction a maximum width B UR (width at the widest point). The tread depth T UR is usually 6.5 mm to 13.0 mm and the maximum width B UR is usually 5.0 mm to 15.0 mm, especially 6.0 mm to 13.0 mm. According to Fig. 2, each circumferential groove 8 is defined by a groove base 8a and two groove flanks 8b, wherein the groove flanks 8b in the exemplary embodiment, viewed in cross-section, extend straight. Furthermore, each circumferential groove 8, viewed in the axially oriented cross-section, has a maximum width B UR bisecting mid-surface M.

[0020] How Fig. 1 shows, the carcass ply 5 runs between the belt assembly 2 and the inner layer 6 as well as between the side walls 4 and the inner layer 6, wherein the carcass ply 5 is folded over around the bead cores (not shown) to form carcass turn-ups 5a and consists of reinforcements embedded in an electrically conductive carcass rubber coating, so that the carcass ply 5 is electrically conductive.

[0021] The side walls 4 are made of an electrically non-conductive rubber material.

[0022] The belt assembly 2 consists of a radially inner belt layer 2a and a radially outer belt layer 2b, wherein the belt layers 2a, 2b each have belt edges 2c and 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, wherein the reinforcements of the radially inner belt layer 2a cross those of the radially outer belt layer 2b in a particularly known manner. The belt layers 2a, 2b are thus electrically non-conductive. The radially inner belt layer 2a projects beyond the belt edges 2c of the radially outer belt layer 2b on both sides.

[0023] The belt bandage 3 covers the belt layers 2a, 2b radially outward, extends over the belt edges 2c of the two belt layers 2a, 2b, contacts the carcass ply 5, is designed in the exemplary embodiment as a single-layer wound bandage, and consists of reinforcements, generally textile, preferably made of nylon, embedded in an electrically conductive bandage rubber coating. The belt bandage 3 is thus electrically conductive.

[0024] How Fig. 2 for the Fig. 1 right tread half shows, is in the area radially inside each circumferential groove 8 between the tread 1 - i.e. the tread base 1 2 - and the belt bandage 3 each have an electrically conductive material strip 9 assigned to the respective circumferential groove 8, wherein the electrically conductive material strips 9 preferably run in the circumferential direction.

[0025] The further design of the material strips 9 is explained below using a single material strip 9.

[0026] The material strip 9 has, viewed in the axially oriented cross-section of the vehicle tire, a thickness s over its entire circumferential extent in the radial direction 1 from 0.50 mm to 1.50 mm, in particular from 0.60 mm to 1.40 mm, preferably from 0.70 mm to 1.30 mm, particularly preferably from 0.80 mm to 1.20 mm, and over its entire circumferential extent a width b determined in the axial direction 1 from 130% to 200%, in particular from 140% to 190%, preferably from 150% to 180%, particularly preferably from 160% to 170%, of the maximum width B UR of the circumferential groove 8 running radially outside of it and passes the radially inwardly continued central surface M of the circumferential groove 8. The width b 1of the material strip 9 is constant over its circumferential extent or varies within the specified range by up to 1.0 mm due to manufacturing reasons. Any varying width b 1 is in particular a consequence of the forces acting during the formation of the profile of the tread 1 as well as the flow processes occurring during vulcanization. The position of the material strip 9 relative to the circumferential groove 8 extending radially outside of it is such that, viewed in the aforementioned cross-section, the material strip 9 is divided by the radially inwardly continuing central surface M of the circumferential groove 8 into two strip sections 9', each with a width b determined in the axial direction. 1 ' from 40% to 60%, in particular from 45% to 55%, preferably from 48% to 52%, of the respective locally present width b 1 of the material strip 9 is divided, i.e. “divided”.

[0027] The material strip 9 preferably consists of an electrically conductive rubber material. Alternatively, the material strip 9 consists, for example, of one or more electrically conductive threads, in particular of an electrically conductive fabric formed from such threads. The or each thread can consist of an electrically conductive material or be a carrier thread consisting of an electrically conductive or electrically non-conductive material with an electrically conductive coating.

[0028] The electrostatic charges occurring during driving are conducted from the vehicle, in particular from the body, to the respective ground (“grounding”) via a discharge path which is formed by the rim, the flange profile, the carcass insert 5, the belt bandage 3, the material strips 9 and the electrically conductive element(s) 7.

[0029] The invention is not limited to the described embodiment.

[0030] The tread can be constructed with a single layer in the radial direction or with more than two layers. Furthermore, the tread or its layers can be constructed with multiple parts in the axial direction. The rubber material of the horn profiles and the carcass rubber lining can be electrically non-conductive. Dissipation via the sidewall region(s), i.e., via the region of the horn profiles and the section of the carcass insert adjacent to the respective sidewall, occurs via at least one electrically conductive sidewall / horn profile passage located in one of the sidewall regions. In the exemplary embodiment, the electrically conductive carcass rubber lining and the horn profiles form electrically conductive sidewall / horn profile passages. The or each electrically conductive sidewall / horn profile passage can alternatively be formed, for example, by electrically conductive threads, an applied electrically conductive suspension, or electrically conductive rubber strips.

[0031] All or some of the circumferential grooves may, when viewed from above, be wave-shaped, for example, in the form of a curved wave or a zigzag wave. Furthermore, the circumferential grooves may have a width that varies along their length. Chamfers (beveled surfaces) or rounded portions extending toward the tread periphery may be provided in the area of ​​the circumferential grooves, which are not taken into account when determining the maximum width.

[0032] In the context of the present invention, an electrically conductive material is understood to be one which has a specific electrical resistance of ≤ 10 8Ohm·cm. The electrically conductive material (e.g. rubber material, rubber lining, fabric, coating, suspension) underlying the respective tire component (e.g. element 7, belt bandage 3, material strip 9, carcass insert 5, flange profile, passage) therefore has a specific electrical resistance of ≤ 10 8 Ohm·cm. An electrically conductive thread or electrically conductive carrier thread is one which has an electrical resistance of ≤ 10 6 Ohm per 30 cm thread length (=10 MOhm per 30 cm thread length). List of reference symbols 1 tread 1a exterior surface 1 1 Tread cap 1 2 Tread base 2 belt bandage 2a radial inner belt layer 2b radial outer belt layer 2c belt edge 3 belt bandage 4 side wall 5 Carcass insert 5a Carcass roll-up 6 inner layer 7 electrically conductive element 8 circumferential groove 8a groove base 8b groove flank 9 electrically conductive material strips 9' strip section AA line (tyre equatorial plane) A Double arrow (axial direction) B, b 1 , b 1 ' Width B UR maximum width M mid-surface R double arrow (radial direction) S 1 Strength T UR Tread depth Z 2 detail QUOTES CONTAINED IN THE DESCRIPTION

[0000] This list of documents submitted by the applicant was generated automatically and is included solely for the convenience of the reader. This list is not part of the German patent or utility model application. The DPMA assumes no liability for any errors or omissions. Cited patent literature

[0000] EP 3 680 114 A1

[0002]

Claims

[1] Vehicle tire with a profiled tread (1) made of electrically non-conductive rubber material, a belt assembly (2) with at least two belt layers (2a, 2b) with an electrically non-conductive belt rubber coating, a belt bandage (3) covering the belt layers (2a, 2b) at the edges in the tire cross-section and with an electrically conductive bandage rubber coating, at least one electrically conductive element (7) penetrating the tread (1) in the radial direction and contacting the belt bandage (3), and at least one electrically conductive sidewall / flange profile passage (5) formed in a sidewall region and contacting the belt bandage (3), which, when the vehicle tire is mounted on the rim, is in electrically conductive connection with the rim, wherein a discharge path for discharging electrostatic charges is formed, which comprises the sidewall / flange profile passage (5), the belt bandage (3), and the electrically conductive element(s) (7), and where an electrically conductive material is one which has a specific electrical resistance of ≤ 10 8 Ohm·cm, characterized by that the tread (1) has at least one profile depth (T UR ) circumferential groove (8) with a maximum width (B UR ), wherein the discharge path comprises an electrically conductive material strip (9) installed radially within the circumferential groove (8) between the tread (1) and the belt bandage (3) and associated with the circumferential groove (8), which, viewed in the tire cross-section, has a width (b 1 ) from 130% to 200% of the maximum width (B UR ) of the circumferential groove (8). [2] Vehicle tyre according to claim 1, characterized by that the width (b 1) of the electrically conductive material strip (9) 140% to 190%, in particular 150% to 180%, preferably 160% to 170%, of the maximum width (B UR ) of the circumferential groove (8). [3] Vehicle tyre according to claim 1 or 2, characterized by that the electrically conductive material strip (9) has a thickness (s 1 ) from 0.50 mm to 1.50 mm, in particular from 0.60 mm to 1.40 mm, preferably from 0.70 mm to 1.30 mm, particularly preferably from 0.80 mm to 1.20 mm. [4] Vehicle tyre according to one of claims 1 to 3, characterized by that the electrically conductive material strip (9), viewed in the tire cross-section, is defined by a maximum width (B UR ) of the circumferential groove (8) is divided into two strip sections (9'), each of which has a width (b 1') of 40% to 60%, in particular of 45% to 55%, preferably of 48% to 52%, of the width (b) present in the respective tire cross-section 1 ) of the material strip (9). [5] Vehicle tyre according to one of claims 1 to 4, characterized by that the electrically conductive material strip (9) runs in the circumferential direction. [6] Vehicle tyre according to one of claims 1 to 5, characterized by that the electrically conductive material strip (9) - is an electrically conductive rubber material or at least an electrically conductive thread. - an electrically conductive rubber material or at least one electrically conductive thread, wherein an electrically conductive thread is one which has an electrical resistance of ≤ 10 6 Ohm per 30 cm of thread length. [7] Vehicle tyre according to claim 6, characterized bythat the electrically conductive material strip (9) comprises a plurality of electrically conductive threads or is an electrically conductive fabric formed from a plurality of electrically conductive threads.

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