Vehicle tire and method for producing a belt assembly

Abstract

The invention relates to a vehicle tire (1) with a belt assembly (2), comprising a first ply (3), wherein a first edge of the first belt ply (3) is surrounded by a first belt edge padding (4), and the first belt ply (3) and the first belt edge padding (4) comprise electrically non-conductive rubber mixtures. A second belt edge padding (5) surrounds the first edge of the first belt ply (3) and the first belt edge padding (4), and the second belt edge padding (5) comprises an electrically conductive rubber mixture.

Description

[0001] Vehicle tires and method for producing a belt assembly

[0002] Description

[0003] The invention relates to a vehicle tire with a belt assembly comprising a first belt ply, wherein a first edge of the first belt ply is covered with a first belt edge pad, wherein the first belt ply and the first belt edge pad comprise electrically non-conductive rubber mixtures.

[0004] It is common practice to wrap each edge of a belt ply with a belt edge pad to isolate sharp and pointed elements and thus preserve the integrity of the vehicle tire. Furthermore, a belt edge pad can help absorb and absorb the dynamics of the belt ply generated during tire rolling, thus ensuring the stability and integrity of the vehicle tire.

[0005] Furthermore, it is increasingly common to use low-rolling-resistance rubber compounds to reduce the rolling resistance of vehicle tires. These low-rolling-resistance rubber compounds often exhibit a higher specific electrical resistance than conventional rubber compounds. For example, silica is commonly used as a filler instead of carbon black, which can advantageously achieve low rolling resistance, but can result in problematically high electrical resistance between the road surface and the rim.

[0006] The goal is therefore to create an electrical bridge in the vehicle tire, which, for example, must also overcome a belt layer arranged between the road surface and the rim if the belt layer has excessive electrical resistance. DE 10 2017 211 762 A1 provides for this purpose electrically conductive threads on the underside of a belt bandage and on the upper side of a belt layer, which together form a grid-like electrical conductor. An electrically conductive belt edge pad is also provided, which is in contact with the grid-like electrical conductor on the one hand and with an electrically conductive carcass ply on the other.

[0007] One problem when creating electrical bridges can be that rubber compounds with different electrical conductivity are difficult to combine with each other due to different chemical and / or physical properties, so that in vehicle tires, particularly at contact points subject to high mechanical stress, a connection between two assemblies based on different rubber compounds can degrade.

[0008] The invention is based on the object of creating an electrical bridge in a vehicle tire based at least partially on electrically non-conductive rubber compounds that does not negatively affect the stability and integrity of the vehicle tire. Furthermore, a method for producing a belt assembly, in particular for a vehicle tire according to the invention, is to be created that can be carried out in a straightforward and cost-effective manner.

[0009] The stated object is achieved according to the invention in that a second belt edge pad surrounds the first edge of the first belt layer and the first belt edge pad, wherein the second belt edge pad comprises an electrically conductive rubber mixture.

[0010] The invention resolves the conflicting objectives between an electrical bridge and high tire stability at a high level and in a surprisingly simple manner, without requiring costly and / or complex means. Between the first belt edge cushion, which comprises a non-electrically conductive rubber compound, and the first belt layer, which comprises a similar rubber compound, a conventional contact point is created which is homogeneous in terms of the rubber compounds, wherein the homogeneous contact point easily absorbs mechanical loads at the first edge of the first belt layer. The first belt edge cushion acts as a type of mechanical buffer layer, absorbing a large portion of the dynamics from the first belt layer, such that a contact point between the first belt edge cushion and the second belt edge cushion is subjected to less mechanical stress than the contact point between the first belt layer and the first belt edge cushion.For this reason, the inherently less resilient contact point between the first belt edge pad and the second belt edge pad, which comprises a conductive rubber compound and is heterogeneous in terms of rubber compounds, remains stable even under heavy loads on the vehicle tire. The second belt edge pad can thus serve as a link in a chain of highly electrically conductive components in the vehicle tire without compromising tire stability, thus providing a continuous electrically conductive channel that can extend from a road surface to a rim.

[0011] When the directional terms axial, axial direction, radial, radial direction, and circumferential direction are used in relation to the vehicle tire, these refer to the vehicle tire as intended and the rolling movement it performs. The radial direction refers to a direction perpendicular to the rotation axis of the vehicle tire and intersecting the rotation axis. In the radial direction inward refers to the orientation that faces the rotation axis in the radial direction. In the radial direction outward refers to the orientation that faces away from the rotation axis in the radial direction. The circumferential direction refers to the direction of a rolling movement around the rotation axis.As the vehicle moves forward, a circumferentially forward position on the vehicle tire passes through a minimum distance to the road surface earlier than a circumferentially rearward position during a 360° rotation of the vehicle tire, with the circumferentially rearward position passing through its minimum distance to the road surface less than 180° behind the forward position. The axial direction refers to a direction parallel to the axis of rotation. Pointing axially inward refers to an orientation that faces a tire equator plane or a tire equator line. The tire equator plane is a plane perpendicular to the axis of rotation of the vehicle tire that runs through the center of the axial width of the vehicle tire, with the tire equator line running in the tire equator plane and on the surface of the vehicle tire.The transverse direction is a direction that consists of components of the radial direction and / or the axial direction.

[0012] The effects achieved with the features of the main claim are supported and further enhanced by preferred embodiments and configurations.

[0013] A rubber compound is considered to be non-electrically conductive if its specific resistance after vulcanization is at least 1 x 10 8 Q cm. A rubber compound is considered electrically conductive if its specific resistance after vulcanization is less than 1 x 10 8 Q cm.

[0014] Particularly preferred is an embodiment according to which the first belt layer and the first belt edge pad comprise rubber compounds optimized for low rolling resistance. Rubber compounds with silica as a filler can be used for this purpose. Preferably, no other rubber compounds are used in the first belt layer and the first belt edge pad besides the non-conductive rubber compounds. Preferably, only one rubber compound is used for each of the first belt layer and the first belt edge pad, and more preferably, the same rubber compound is used.

[0015] The second belt edge pad preferably comprises a rubber compound having a specific resistance of less than 1 x 10 7 Q cm and no other rubber compounds besides this rubber compound.

[0016] A belt ply in a vehicle tire runs essentially in the transverse direction and in the circumferential direction and has an edge on the outside on both sides of the vehicle tire in the axial direction. A belt edge cushion extends over the entire circumference of the vehicle tire and the belt ply arranged therein. A belt edge cushion encloses an edge of a belt ply if, in a cross-section perpendicular to a longitudinal extent of the belt ply, or in a cross-sectional plane spanned by the radial direction and the axial direction, the edge of the belt ply is completely surrounded by the belt edge cushion, so that, viewed from a point on the edge, the belt edge cushion rests against the belt ply over an angular range of at least 180°. A second belt edge cushion encloses an edge of a belt ply and a first belt edge cushion if, in a cross-section perpendicular to a longitudinal extent of the belt ply, or in a cross-sectional plane spanned by the radial direction and the axial direction, the edge of the belt ply is completely surrounded by the belt edge cushion, so that, viewed from a point on the edge, the belt edge cushion rests against the belt ply over an angular range of at least 180°.in a cross-sectional plane spanned by the radial direction and the axial direction, the edge of the first belt ply and an edge portion of the first belt edge cushion are completely surrounded by the belt edge cushion, so that, viewed from a point in the edge portion of the first belt edge cushion, the second belt edge cushion bears against the first belt edge cushion over an angular range of at least 180°, and so that, viewed from a point on the edge of the belt ply, the second belt edge cushion bears against the first belt edge cushion over an angular range of at least 180°. An edge portion of a belt edge cushion enclosing an edge of a belt ply can be defined as a portion of the belt edge cushion that is not intersected by any perpendicular to the surfaces of the belt ply, i.e., is arranged outside the belt ply in the transverse direction in the vehicle tire.The sections of the belt edge pad cut by a perpendicular on the surfaces of the belt layer may be referred to as turn-up sections.

[0017] The first belt edge pad and the second belt edge pad can each comprise a radially inner and a radially outer turn-up section. This can result in a stacked structure in the radial direction consisting of—viewed from radially inside to radially outside—a radially inner turn-up section of the second belt edge pad, a radially inner turn-up section of the first belt edge pad, the first belt ply, a radially outer turn-up section of the first belt edge pad, and a radially outer turn-up section of the second belt edge pad. The radially inner and outer turn-up sections of a belt edge pad are connected to one another via an edge section of the belt edge pad.In one of the two belt edge cushions, the radially inner turn-up section can have a smaller axial extent than the radially outer turn-up section, whereby in the other belt edge cushion, the radially inner turn-up section can have a greater axial extent than the radially outer turn-up section. By arranging the two belt edge cushions asymmetrically in this way, a direct connection can be achieved between the first belt layer and the second belt edge cushion via the longer turn-up section of the second belt edge cushion, which can mean stronger networking of components and thus greater stability. Furthermore, excessive thickening in the area of ​​the first edge of the first belt layer can be avoided by arranging the two belt edge cushions not one above the other on the first belt layer across the entire width of both belt edge cushions, but with a certain offset.

[0018] In a particularly preferred embodiment, the radially inner turn-up section of the first belt edge cushion has a smaller axial extent than the radially outer turn-up section, wherein the radially inner turn-up section of the second belt edge cushion has a greater axial extent than the radially outer turn-up section. This makes it possible to find a particularly favorable path for the electrical bridge through the vehicle tire, wherein the radially inner turn-up section of the second belt edge cushion can project axially inward so far that a sufficiently large contact surface can still be created between the radially inner turn-up section and a carcass within an axial extent of a sidewall.

[0019] The vehicle tire may comprise a tread, wherein the tread comprises an electrically conductive channel radially penetrating the tread. If the tread, apart from the conductive channel, consists essentially of an electrically non-conductive rubber compound, the electrically conductive channel may be produced in a basically known manner, for example in the form of a so-called carbon center beam, which usually radially penetrates the tread near the tire equator line and is designed to contact a road surface. The belt assembly may comprise a belt bandage, wherein the belt bandage may be electrically conductive at least on its surfaces and may be in contact, on the radially outer surface, with the radially inner end of the electrically conductive channel in the tread.The vehicle tire can additionally comprise a carcass, wherein the carcass is electrically conductive at least on its outer surface. The carcass can consist of several layers, wherein the outer surface of the carcass is a radially and / or axially outward-facing surface. Overall, a continuous electrically conductive channel can run through the tread, the belt bandage, and the carcass. In a preferred embodiment, there is no direct electrical connection between the belt bandage and the carcass, although the second belt edge cushion electrically conductively connects the belt bandage and the carcass. In the manner described, electrical charge can be shifted and discharged between a rim, which can be conductively connected to the carcass, and a road surface, which can be connected to the conductive channel in the tread.Overall, the specific resistances and dimensions of the assemblies defining the electrically conductive channel should be such that the electrical channel has a resistance of less than 1x10. 10 Q, preferably less than 1x10 8 Q has.

[0020] The tread can consist largely of an electrically non-conductive rubber compound. Preferably, the tread consists exclusively of an electrically non-conductive rubber compound, apart from the electrically conductive channel radially penetrating the tread. The vehicle tire preferably comprises a sidewall, wherein the sidewall comprises an electrically non-conductive rubber compound and preferably consists exclusively of an electrically non-conductive rubber compound. The belt assembly preferably comprises a second belt ply, wherein the second belt ply is covered by a further belt edge pad. Preferably, the second belt ply and the further belt edge pad comprise electrically non-conductive rubber compounds. Preferably, no further rubber compounds are used in the two aforementioned assemblies besides the non-conductive rubber compounds.Preferably, one and more preferably the same rubber compound is used for each of the second belt ply and the additional belt edge pad. A particularly preferred embodiment is one in which the tread, the sidewall, the second belt ply, and the additional belt edge pad comprise rubber compounds optimized for low rolling resistance. Rubber compounds with silica as a filler can be used for this purpose.

[0021] In a preferred embodiment, a second edge of the first belt ply is wrapped with two belt edge pads, similar to the first edge. All or some of the features described above and / or below for the first edge can apply to the belt pads and the type of wrapping on the second edge. Preferably, the two edges, including the surrounding belt edge pads, are designed essentially identically.

[0022] The invention further relates to a method for producing a belt assembly, wherein in a first method step a first edge of a first belt layer is covered with a first belt edge pad, wherein the first belt layer faces upwards with a first surface, wherein the first belt edge pad is applied to the first surface with a first turn-up section and a second turn-up section of the first belt edge pad is folded around the first edge of the first belt layer onto a downwards-facing second surface of the first belt layer. The method is characterized in that the first turn-up section of the first belt edge pad is wider than the second turn-up section of the first belt edge pad, wherein in a later method step the first edge of the first belt layer and the first belt edge pad are covered with a second belt edge pad.In this case, in the later method step, the first belt ply points with the second surface facing upwards, wherein the second belt edge pad is brought with a first turn-up section onto the second surface and / or onto the second turn-up section of the first belt edge pad, and a second turn-up section of the second belt edge pad is turned over around the first edge of the first belt ply and an edge section of the first belt edge pad onto the first surface of the first belt ply and / or onto the first turn-up section of the first belt edge pad, wherein the first turn-up section of the second belt edge pad is wider than the second turn-up section of the second belt edge pad.

[0023] The first belt ply has two opposing surfaces, wherein the two surfaces are preferably substantially identical in design, i.e., interchangeable. The first surface is thus preferably an arbitrarily selectable surface of the first belt ply. Typically, the identification of a surface as the first surface or second surface is determined by orientation on a conveyor belt of a production line, during which the first belt edge pad is applied to the first edge of the first belt ply.

[0024] The first turn-up section of the first belt edge cushion is wider than the second turn-up section of the first belt edge cushion if the first turn-up section has a greater axial extent than the second turn-up section on a first belt ply arranged as intended in the vehicle tire. Analogously, the first turn-up section of the second belt edge cushion is wider than the second turn-up section of the second belt edge cushion if it has a greater axial extent than the second turn-up section of the second belt edge cushion. In the context of a belt assembly arranged as intended in the vehicle tire, the first turn-up section of the first belt edge cushion is preferably a radially outer turn-up section of the first belt edge cushion. Analogously, the first turn-up section of the second belt edge cushion is preferably a radially inner turn-up section of the second belt edge cushion.

[0025] The second belt edge pad can be folded over with a first folded portion onto the second folded portion of the first belt edge pad or onto the second folded portion of the first belt edge pad and the second surface of the first belt layer. The second folded portion of the second belt edge pad can be folded over around the first edge of the first belt layer and the edge portion of the first belt edge pad onto the first folded portion of the first belt edge pad or onto the first folded portion of the first belt edge pad and onto the first surface of the first belt layer.Preferably, the second belt edge pad is placed with the first folded portion onto the second surface of the belt layer and onto the second folded portion of the first belt edge pad, wherein the second folded portion of the second belt edge pad is folded around the first edge of the first belt layer and the edge portion of the first belt edge pad only onto the first folded portion of the first belt edge pad. This preferred embodiment can be achieved in particular when the first folded portion of the second belt edge pad is wider than the second folded portion of the first belt edge pad and when the second folded portion of the second belt edge pad is narrower than the first folded portion of the first belt edge pad.An embodiment in which none of the turn-up sections of the second belt edge cushion touches a turn-up section of the first belt edge cushion is also conceivable, for example if a separating layer is arranged between the two belt edge cushions. The application and turning over of the belt edge cushions to be carried out on the belt layer for the first and for the subsequent method step can be effected in a manner known per se using means known per se. For example, a first belt edge cushion can be attached to each of the edges of a belt layer by unwinding the two first belt edge cushions in a conveyor line from two rollers arranged above the edges of the belt layer synchronously with a conveying movement of the belt layer and pressed against the first surface of the belt layer in first turn-up sections, so that second turn-up sections protrude beyond the edges of the belt layer on both sides of the belt layer.The folded sections extending laterally over the edges can then be folded over on the same conveyor line and pressed onto the second surface of the belt layer. Similarly, a second belt edge pad can be applied to each edge of the belt layer. Production lines that can be advantageously used for the first and subsequent process steps are described in more detail below.

[0026] A middle process step can be performed between the first and the subsequent process step. For this purpose, the first belt layer with the first belt edge padding surrounding the first edge can be wound onto a first cassette in a first direction of rotation at the end of the first process step. In the middle process step, the first belt layer with the first belt edge padding surrounding the first edge is then rewound from the first cassette to a second cassette, with the second cassette being rinsed in a second direction of rotation. Conventional devices for winding and unwinding belt layers can be used as cassettes.Typically, the belt ply is wound onto a drum around an axis perpendicular to its longitudinal extent and parallel to its surfaces. To protect and separate the individual windings of the belt ply, an intermediate layer can be unwound from an idler and wound onto the drum with the belt ply. The belt ply can be unwound from the drum in a similar way. The direction of rotation in which the belt ply is wound onto a cassette depends on the orientation of the belt ply in the cassette: The belt ply can be wound onto the cassette so that a given surface of the belt ply faces radially inwards or outwards. Here, the radial direction, analogous to the context of a vehicle tire, refers to a direction perpendicular to the axis of rotation of the cassette or to the axis of rotation of a drum of the cassette and intersecting the axis of rotation.

[0027] By changing the direction of rotation of the belt layer in the cassettes during the middle process step, the change in the orientation of the first and second surfaces required between the first and later process steps can be simplified. The first direction of rotation in which the first cassette is rinsed can, in the context of a typical production environment, result in the first belt layer, if fed directly from the first cassette into a production line for the later process step, having its first surface facing upwards. Instead, after the belt layer has been rewound from the first to the second cassette, the first belt layer can be fed from the second cassette into the production line for the later process step with the second surface facing upwards for the later process step.Thus, the simple middle process step avoids the need for complex remodeling of the production environment. Alternatively, the production environment could be designed so that the first cassette is immediately rinsed in the second direction of rotation at the end of the first process step. Alternatively, the first cassette could be loaded into the production line the other way round for the subsequent process step, so that the second surface of the first belt layer faces upward for the subsequent process step.

[0028] In a preferred embodiment, the second cassette is loaded into a production line after the middle process step and at the beginning of the later process step, and the first belt layer is unwound from the second cassette onto the production line such that the first belt layer faces upwards with the second surface in the later process step.

[0029] The first process step can be carried out on a production line where the steel cord can be cut in a first section of the production line. In this case, a steel cord web can be punched into strips at a predetermined angle of, for example, between 18° and 32°, each corresponding to the width of the belt layer, in a conventional manner. The individual punched sections can then be butt-jointed in a conventional manner using a splicing roller, creating a straight-edged endless belt that can be further processed, for example, as the first belt layer.The assembly of the strips to form the first belt layer, the wrapping of the first edge of the first belt layer with the first belt edge pad in the first process step and the winding of the first belt layer together with the first belt edge pad onto the first cassette can be carried out in a manner known per se on a continuous conveyor line.

[0030] The subsequent process step can be carried out on the same production line as the first process step. Instead of the steel cord sections, the first belt layer wrapped with the first belt edge pad can be brought onto the production line.

[0031] In addition to the first edge, a second edge of the first belt ply can be covered with two belt edge pads. All or some of the features described above and / or below for the first edge can apply to the application of the belt edge pads to the second edge. To apply the belt edge pads in two opposite edge regions of the belt ply and to fold over the second fold-over sections, means and movement sequences can be used that are symmetrical to a mirror plane, wherein the mirror plane is arranged centrally in the width direction of the belt ply and runs perpendicular to the belt ply along the longitudinal direction. In a preferred embodiment, the first and second edges of the first belt ply are covered simultaneously, with the first belt edge pads being applied synchronously to one another on both edges and the second belt edge pads being applied synchronously to one another on both edges.In other words, the sheathing on both edges is preferably carried out in an identical manner and in parallel.

[0032] The method can be further developed with additional features that are described in connection with the vehicle tire according to the invention. The vehicle tire can be further developed with additional features that are described in connection with the method according to the invention.

[0033] The invention is described below by way of example with reference to the accompanying drawings using advantageous embodiments. They show:

[0034] Figure 1 schematically shows a sectional view of a shoulder region of an embodiment of a vehicle tire according to the invention,

[0035] Figure 2 schematically shows a production line for the manufacture of a belt bandage according to the invention,

[0036] Figure 3 schematically shows an advantageous, middle process step for producing a belt bandage according to the invention,

[0037] Figure 4 schematically shows a production line for the manufacture of a belt bandage according to the invention,

[0038] Figure 5 schematically shows a first method step for the inventive

[0039] Production of a belt bandage, Figure 6 schematically shows a later process step for the production of a belt bandage according to the invention.

[0040] Vehicle tires designed according to the invention are tires of any design, in particular radial tires, and tires of any type, in particular pneumatic vehicle tires for motor vehicles, such as passenger cars, light trucks or commercial vehicles and in particular for vans.

[0041] Figure 1 shows a sectional view of a shoulder region of an embodiment of a vehicle tire according to the invention. The sectional plane runs perpendicular to the circumferential direction and is spanned by the axial and radial directions. In a manner known per se, the vehicle tire has a carcass 11, which can consist of several plies not shown in detail. The carcass 11 is designed to be electrically conductive at least on its outer surface, for example by using an electrically conductive rubber compound. A sidewall 15 rests laterally on the carcass, wherein the sidewall 15 consists of an electrically non-conductive rubber compound with silica as a filler. Radially outside the carcass 11 follows a belt assembly with two belt plies 3, 13 and a belt bandage 12. The belt plies 3, 13 comprise non-electrically conductive rubber compounds and are not electrically conductive overall.The belt bandage 12 is designed to be electrically conductive on its radially inner and outer surfaces, for example through the use of an electrically conductive rubber compound. Arranged radially outside the belt bandage 12 is a tread with a tread base 10b and a tread cap 10a, wherein the tread 10a, 10b consists of one or more electrically non-conductive rubber compounds with silica as a filler. An electrically conductive channel in the form of a carbon center beam penetrates the tread 10a, 10b axially centrally, at a location outside the depiction area of ​​Figure 1. The carbon center beam can extend radially through the entire tread 10a, 10b, axially over a width of several centimeters, and circumferentially over the entire vehicle grip.The Carbon Center Beam consists of an electrically conductive rubber compound with carbon black as a filler and can establish an electrical contact between a road surface and the belt bandage 12, thereby bridging the electrically non-conductive tread 10a, 10b.

[0042] The edge of the radially outer second belt layer shown in Figure 1

[0043] 13 is covered with a belt edge pad 14, wherein the belt edge pad

[0044] 14 comprises an electrically non-conductive rubber mixture and is electrically non-conductive overall. The illustrated first edge of the first belt ply 3 is covered with two belt edge cushions 4, 5, which are identified in Figure 1 by opposing hatching. The first belt edge cushion 4 comprises a first, radially outer circumferential section 4a and a second, radially inner circumferential section 4b, wherein the first circumferential section 4a of the first belt edge cushion 4 is wider, i.e. has a greater axial extent than the second circumferential section 4b. The first belt edge cushion 4 comprises an electrically non-conductive rubber mixture and is electrically non-conductive overall.The second belt edge cushion 5 comprises a first, radially inner circumferential section 5a and a second, radially outer circumferential section 5b, wherein the first circumferential section 5a of the second belt edge cushion 5 is wider, i.e. has a greater axial extent than the second circumferential section 5b. The second belt edge cushion 5 comprises an electrically conductive rubber mixture and is also electrically conductive overall. The second belt edge cushion 5 is connected and in electrical contact with the belt bandage 12 radially outwardly and with the carcass 11 radially inwardly. Due to the large axial extent of the first turn-up section 5a of the belt edge cushion 5, contact between the second belt edge cushion 5 and the carcass 11 can be established axially within an extent of the electrically non-conductive sidewall 15.

[0045] Overall, this results in a coherent electrically conductive channel consisting of the carbon center beam (not shown in Figure 1), the belt bandage 12, the second belt edge pad 5, the carcass 11, and a rim (not shown in Figure 1). The electrically conductive channel acts as an electrical bridge through the otherwise predominantly electrically non-conductive components of the vehicle tire.

[0046] Figure 2 shows a production line 8 on which the method according to the invention for producing a belt assembly with two belt edge cushions 4, 5 arranged on one edge of a belt ply 3 can be used. At the entrance to the production line 8, a roll 16 from the steel cord calender is arranged, from which a calendered steel cord web 17 is unwound. Not shown in Figure 2 are an intermediate layer for protecting and separating the individual windings of the steel cord web 17 on the roll 16 and an idler intended for winding the intermediate layer. In a punching station 18, the steel cord web is punched into strips using a cutting means (not shown), wherein the strips each have a width corresponding to the first belt ply 3.The individual sections punched in this way are then butt-jointed in a splice station 19, shown only schematically as a black box in Figure 2, to produce a straight-edged endless belt that is further processed as belt layer 3. Not shown in Figure 2 are conveyor belts on which the steel cord web 17, the punched sections, and the first belt layer 3 are conveyed along the first production line 8. At the end of the production line 8, the first belt layer 3 is wound onto a first cassette 6 in a first direction of rotation. The direction of rotation shown corresponds to a mathematical direction of rotation when viewed from an edge of the belt layer 3 located to the right on the conveyor line and is to be referred to as the first direction of rotation only within the context of the embodiment described in Figures 2 to 4; in other embodiments with different production environments, a counter-rotating winding could also be referred to as the first direction of rotation.Not shown in Figure 2 are an intermediate layer for protecting and separating the individual windings of the first belt layer 3 on the first cassette 6 and a follower intended for winding the intermediate layer.

[0047] After the sections have been assembled to form the first belt layer 3 in the splice station 19 and before winding onto the first cassette 6, the first method step according to the invention is carried out in the first production line 8. A first wrapping station used for this purpose is shown only schematically in Figure 2 as a black box marked with the Roman numeral V, into which the first belt layer 3 runs and emerges again wrapped on both edges with belt edge cushions 4 (not shown graphically in Figure 2). Figure 5 shows the sequence of the first method step schematically and functionally, i.e., without considering the structural aids required for implementation: Accordingly, a first edge of a first belt layer 3 is wrapped with a first belt edge cushion 4.For this purpose, the first belt ply 3 faces upwards with a first surface 3a, wherein the first belt edge pad 3 is brought onto the first surface 3a with a first turn-up section 4a, and a second turn-up section 4b of the first belt edge pad 4 is folded around the first edge of the first belt ply 3 onto a downward-facing second surface 3b of the first belt ply 3. A first turn-up section 4a of the first belt edge pad 4 is wider than a second turn-up section 4b of the first belt edge pad 4.

[0048] Figure 3 shows a middle process step: After the first belt layer 3, with its edges wrapped by first belt edge cushions 4, has been wound onto the first cassette 6 at the end of the production line 8 in a first direction of rotation, the first belt layer 3 is rewound onto a second cassette 7 in a second direction of rotation. During this process, the orientation of the surfaces of the first belt layer 3 changes from radially inward or radially outward with respect to the first cassette 6 to radially outward or radially inward with respect to the second cassette 7. Not shown in Figure 3 are intermediate layers for protecting and separating the individual windings of the first belt layer 3 on the cassettes 6, 7, and the idlers used to wind the intermediate layers.

[0049] According to Figure 4, following the middle process step, the second cassette 7 is loaded into the entrance of a production line 8, which may be identical to the production line 8 for the first process step. The first belt ply 3, together with the belt edge cushions 4 surrounding its edges, is unwound from the second cassette 7 so that a second surface of the first belt ply 3 faces upward. Not shown in Figure 4 are an intermediate layer for protecting and separating the individual windings of the first belt ply 3 on the second cassette 7 and an idler intended for winding the intermediate layer. Also not shown is a conveyor belt for conveying the first belt ply 3 along the production line 8. The later process step according to the invention is carried out on the production line 8.A dedicated second wrapping station is shown schematically in Figure 4 as a black box marked with the Roman numeral VI, into which the first belt ply 3 enters with first belt edge cushions 4 (not shown in the drawing in Figure 4) and exits again wrapped with second belt edge cushions 5 (likewise not shown in the drawing). The wrapping means in the first wrapping station V of Figure 2 and in the second wrapping station VI of Figure 4 can be essentially identical; furthermore, the first and second wrapping stations can also be identical, so that only one wrapping station and one production line are required for the first and the subsequent process steps.

[0050] Figure 6 shows a schematic and functional sequence of the subsequent method step: Accordingly, the first edge of the first belt ply 3 and the first belt edge pad 4 are wrapped with a second belt edge pad 5. For this purpose, the first belt ply 3 faces upward with its second surface 3b, and the second belt edge pad 5 is applied with a first folded portion 5a to the second surface 3b of the first belt ply 3 and to the second folded portion 4b of the first belt edge pad 4. A second folded portion 5b of the second belt edge pad 5 is folded around the first edge of the first belt ply 3 and the edge portion of the first belt edge pad 4 onto the first folded portion 4a of the first belt edge pad 4. The first folded portion 5a of the second belt edge pad 5 is wider than the second folded portion 5b of the second belt edge pad 5.The first belt ply 3 covered with two belt edge cushions 4, 5 in the manner described according to the method according to the invention can be used in a manner known per se for the production of a vehicle tire.

[0051] List of reference symbols

[0052] 3 first belt layer

[0053] 3a first surface

[0054] 3b second surface

[0055] 4 first belt edge pad

[0056] 4a first turn-up section (of the first belt edge pad)

[0057] 4b first turn-up section (of the first belt edge pad)

[0058] 5 second belt edge pad

[0059] 5a first fold-over section (of the second belt edge pad)

[0060] 5b second fold-over section (of the second belt edge pad)

[0061] 6 first cassette

[0062] 7 second cassette

[0063] 8 Production line

[0064] 10a tread (cap)

[0065] 10b Tread (base)

[0066] 11 Carcass

[0067] 12 belt bandage

[0068] 13 second belt layer

[0069] 14 additional belt edge pads

[0070] 15 Side wall

[0071] 16 rolls of steel cord calender

[0072] 17 calendered steel cord web

[0073] 18 punching stations

[0074] 19 Splice station

Claims

Patent claims 1. Vehicle tire with a belt assembly comprising a first belt ply (3), wherein a first edge of the first belt ply (3) is covered with a first belt edge cushion (4), wherein the first belt ply (3) and the first belt edge cushion (4) comprise electrically non-conductive rubber mixtures, characterized in that a second belt edge cushion (5) covers the first edge of the first belt ply (3) and the first belt edge cushion (4), wherein the second belt edge cushion (5) comprises an electrically conductive rubber mixture.

2. Vehicle tire according to claim 1, characterized in that the first belt edge cushion (4) and the second belt edge cushion (5) each comprise a radially inner and a radially outer turn-up section (4a, 4b, 5a, 5b), wherein in the first belt edge cushion (4) the radially inner turn-up section (4b) has an axially smaller extension than the radially outer turn-up section (4a) and wherein in the second belt edge cushion (5) the radially inner turn-up section (5a) has an axially greater extension than the radially outer turn-up section (5b).

3. Vehicle tire according to one of claims 1 to 2, characterized in that the vehicle tire comprises a tread (10a, 10b) and a carcass (11), wherein the tread (10a, 10b) comprises an electrically conductive channel radially penetrating the tread (10a, 10b), wherein the carcass (11) is electrically conductive on its outer surface and wherein the belt assembly comprises a belt bandage (12), wherein the belt bandage (12) is electrically conductive on its surfaces, wherein a continuous electrically conductive channel runs through the tread (10a, 10b), the belt bandage (12) and the carcass (11).

4. Vehicle tyre according to claim 3, characterised in that there is no direct electrical connection between the belt bandage (12) and the carcass (11). Connection exists, wherein the second belt edge pad (5) electrically connects the belt bandage (12) and the carcass (11) to one another.

5. Vehicle tire according to one of claims 3 or 4, characterized in that the electrically conductive channel radially penetrating the tread (10a, 10b) is a carbon center beam.

6. Vehicle tire according to one of claims 3 to 5, characterized in that the tread (10a, 10b) consists largely of an electrically non-conductive rubber compound, wherein the belt assembly comprises a second belt layer (13) with a further belt edge cushion (14), wherein the second belt layer (13) and the further belt edge cushion (14) comprise electrically non-conductive rubber compounds, wherein the vehicle tire comprises a sidewall (15), wherein the sidewall (15) comprises an electrically non-conductive rubber compound.

7. Vehicle tire according to one of claims 1 to 6, characterized in that a second edge of the first belt layer (3) is covered with two belt edge cushions (4, 5) analogously to the first edge.

8. A method for producing a belt assembly, wherein in a first method step a first edge of a first belt layer (3) is covered with a first belt edge pad (4), wherein the first belt layer (3) faces upwards with a first surface (3a), wherein the first belt edge pad (4) is brought onto the first surface (3a) with a first turn-up section (4a) and a second turn-up section (4b) of the first belt edge pad (4) is turned around the first edge of the first belt layer (3) onto a downwardly facing second surface (3b) of the first belt layer (3), characterized in that the first turn-up section (4a) of the first belt edge pad (4) is wider than the second turn-up section (4b) of the first belt edge pad (4), wherein in a later method step the first edge of the first belt layer (3) and the first belt edge pad (4) are covered with a second belt edge pad (5), wherein the first belt layer (3) points upwards with the second surface (3b) in the later method step, wherein the second belt edge pad (5) is brought with a first turn-up section (5a) onto the second surface (3b) and / or onto the second turn-up section (4b) of the first belt edge pad (4), and a second turn-up section (5b) of the second belt edge pad (5) is folded around the first edge of the first belt layer (3) and around an edge section of the first belt edge pad (4) onto the first surface (3a) of the first belt layer (3) and / or onto the first turn-up section (4a) of the first belt edge pad (4), wherein the first turn-up section (5a) of the second belt edge pad is wider than the second turn-up section (5b) of the second belt edge pad (5).

9. Method according to claim 8, characterized in that between the first and the later method step a middle method step is carried out, wherein the first belt layer (3) with the first belt edge cushion (4) is wound onto a first cassette (6) in a first direction of rotation at the end of the first method step, wherein in the middle method step the first belt layer (3) with the first belt edge cushion (4) is rewound onto a second cassette (7) in a second direction of rotation.

10. Method according to claim 9, characterized in that the first belt layer (3) is unwound from the second cassette (7) onto a production line after the middle method step and at the beginning of the later method step, so that the first belt layer (3) points upwards with the second surface (3b) in the later method step.

11. Method according to one of claims 8 to 10, characterized in that the first method step is carried out on a production line (8), wherein the steel cord cutting takes place in a first section of the production line (8).

12. The method according to one of claims 8 to 11, characterized in that a second edge of the first belt layer (3) is wrapped with two belt edge cushions (4, 5) analogously to the first edge.

13. The method according to claim 12, characterized in that the first and second edges of the first belt layer (3) are wrapped simultaneously.

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