Vehicle pneumatic tire and method for building a tire carcass of a vehicle pneumatic tire on a carcass machine

Description

[0001] The invention relates to a vehicle pneumatic tire with a profiled tread, a belt comprising at least two layers, an inner layer, bead areas with bead cores and core profiles, a carcass ply comprising a first carcass layer and a second carcass layer, wherein the first carcass layer has a section extending continuously from bead area to bead area and along the inner layer, axially extending folded sections at the bead cores and further sections extending externally in the bead areas, and wherein the second carcass layer has a section extending continuously from bead area to bead area in contact with the first carcass layer and terminates in the bead areas, wherein the second carcass layer extends in the bead areas between the first carcass layer on one side and the core profiles on the other side and in contact with these components.

[0002] Pneumatic tires with a radial carcass consisting of two carcass plies are known per se. In one of these known designs, the first carcass ply, known as the C-ply, runs continuously from bead section to bead section, around the bead cores from the inside to the outside, and is then radially retracted into the area within the belt structure. The retracted sections are in contact with the continuous section of the carcass ply running from bead section to bead section. The second carcass ply also runs continuously from bead section to bead section, but completely outside the first carcass ply and terminates in the bead sections lateral to the bead cores. In an alternative design, the first carcass ply terminates in a known manner, forming raised edges in the area of ​​the sidewalls or in the area between the core profiles and the belt.When building the tire carcass on the carcass drum of a carcass machine, after the first carcass ply is placed with its lateral overhangs, the core packages consisting of bead cores and core profiles are positioned. The lateral overhangs are then folded over, and the second carcass ply is applied. During the further construction of the tire carcass with horn profiles and sidewalls, air channels often remain along the ends of the second carcass ply. When the completed tire is vulcanized in a vulcanization mold, these air pockets cause localized "shrinkage" of the rubber material, resulting in narrow, circumferential depressions on the outer surface of the finished tire, which impair the tire's quality.

[0003] A vehicle tire of the type mentioned above is known, for example, from US 2020 / 0164688 A1. The tire is, for example, a motorcycle tire or a vehicle tire for passenger cars or commercial vehicles. The tire has a tread, a belt having one, two, or more than two layers, an inner layer, bead areas with bead cores and core profiles, and a carcass ply with a first carcass layer and a second carcass layer. The first carcass layer comprises a section extending continuously from bead area to bead area, axially extending folded sections at the bead cores, and further sections extending externally in the bead areas. The second carcass layer has a section extending continuously from bead area to bead area that contacts the first carcass layer and terminates in the bead areas in the area of ​​and in contact with the core profiles.The ends of the second carcass ply are located at the same level as the radially outer surface of the bead cores or radially outside the surface of the bead cores, so that they terminate offset from the bead cores in the direction of the tread. The carcass ply is intended to exhibit high stiffness and good durability. Furthermore, a method for constructing a tire carcass of a pneumatic vehicle tire on a carcass machine with an expandable carcass drum and two expandable bellows carriers arranged laterally to the carcass drum is disclosed.

[0004] Another such method is known from WO 2006 / 003054 A1, in which the placement of tire components on the carcass drum is supported and automatic splicing of the end sections is supposed to be possible.

[0005] The US 2018 / 0117969 A1 shows in Fig. 3A pneumatic tire for passenger cars with a carcass consisting of three plies. The two innermost plies are wrapped around the bead cores from the inside out, forming raised edges that terminate radially offset from each other. The third ply is the outermost of the three, running continuously from bead section to bead section in contact with the middle ply, and terminating on the outer side of each bead section at the radially inner ends of the bead cores.

[0006] The invention is based on the objective of avoiding the formation of the aforementioned air channels or inclusions and the formation of unsightly depressions on the outside of the vulcanized tire in order to produce tires of impeccable quality.

[0007] As regards the vehicle pneumatic tire, the problem set out in the invention is solved by the fact that the second carcass layer ends on the outside, laterally to the side of the bead cores and in contact with the bead cores.

[0008] The method according to the invention comprises the following successive steps: a) Expanding the bellows supports so that the outer surfaces of the uninflated bellows, together with the outer surface of the expanded carcass drum, form a uniform cylindrical bearing surface; b) Applying an inner layer and a first carcass ply, projecting laterally beyond the carcass drum, onto the carcass drum; c) Retracting the two bellows supports so that the outer diameters of the bellows decrease relative to the outer diameter of the carcass drum, and the projections of the first carcass ply run along the shoulders of the carcass ply; d) Placing core packs made of bead cores, including core profiles, onto the lateral projections of the first carcass ply in the area of ​​the shoulders of the carcass drum; e) Rolling the core packs laterally against the carcass ply; f) Applying a second carcass ply, which is wide enough to extend laterally from the core packs at least to the area laterally of the bead cores, but at most to the projections of the first carcass ply.g) Rolling the second carcass ply onto the core packs, h) Inflating the bellows to fold over the lateral overhangs of the first carcass ply along the core packs and the second carcass ply, i) Completing the tire carcass in a known manner.

[0009] According to the invention, the end sections of the second carcass ply located in the bead areas are therefore enclosed between the core packs and the first carcass ply and in contact with these components, so that the "bonding" of these components ensures proper formation of the bead areas. The folding of the first carcass ply around the second carcass ply during the construction of the tire carcass prevents the formation of air pockets and thus the formation of the undesirable indentations on the outside of the vulcanized tire.

[0010] In a preferred design, the second carcass layer ends laterally to the side of the beginning of the fold section of the first carcass layer.

[0011] For tires that are subjected to particularly high loads during operation, it is advantageous if the sections of the first carcass layer running on the outside in the bead areas extend along the second carcass layer into an area radially inside the radially inner belt layer, so that the radially inner belt layer overlaps with end sections of the first carcass layer.

[0012] In an alternative design, the sections of the first carcass layer running outwards in the bead areas end as a raised edge towards the side walls.

[0013] Preferably, the reinforcing elements in the first and second carcass plies extend at least partially in a radial direction. In this case, they extend radially around the entire circumference of the tire, at least in areas of one carcass ply that are not located under the tread and not yet in the bead areas. However, the reinforcing elements can also extend completely radially in one or both carcass plies.

[0014] Further features, advantages, and details of the invention will now be described in more detail with reference to the schematic drawing, which illustrates exemplary embodiments. Fig. 1 and Fig. 2 Schematic representations of cross-sections of a tire carcass for a vehicle pneumatic tire with different embodiments of the invention and Figs. 3 to 7successive process stages in the construction of a tire carcass on a carcass drum of a carcass machine.

[0015] In the following description, terms such as "inside", "outside", "inside" and "outside" refer to the position of the component in question in relation to the tire interior.

[0016] Vehicle pneumatic tires designed according to the invention are radial tires for motor vehicles, preferably tires for passenger cars, SUVs, vans or light trucks.

[0017] Fig. 1 and Fig. 2 Each shows a tire carcass with bead areas 2 with bead cores 3 and core profiles 4, sidewalls 5, horn profiles 14, an inner layer 8 and a carcass insert made of a first carcass layer 9 ( Fig. 1 ), 9' ( Fig. 2) and a second carcass layer 10. Above the tire carcass, a tread 1 and a belt 6, which in this example has two belt layers 6a and 6b, with a belt bandage 7 are shown, whereby the tire carcass is built up with these components to form the raw tire, which is then vulcanized. The tire may also have further components, for example bead reinforcement layers.

[0018] The two carcass layers 9, 9' and 10 contain in particular textile reinforcements, for example made of polyester or polyamide, which are embedded in a rubber material, the carcass rubber lining, and run within the carcass layers 9, 9', and 10 at least substantially in a radial direction, therefore at right angles to the circumferential direction of the tire.

[0019] At the in Fig. 1In the embodiment shown, the carcass layer 9 is designed as a so-called C-layer. The carcass layer 9 has a section 9a which runs continuously from bead area 2 to bead area 2 within and in contact with the inner layer 8. The carcass layer 9 surrounds the bead cores 3 from the inside to the outside with a folded section 9d and then runs with a section 9b initially along the core profiles 4 and then in contact with the carcass layer 10 and into a region radially within the radially inner belt layer 6b, such that the radially inner belt layer 6b overlaps with end sections 9c of the carcass layer 9. The overlapped region preferably has a width b of 5.00 mm to 25.00 mm in the axial direction.

[0020] The second carcass ply 10 also extends continuously from bead area 2 to bead area 2. Radially outside the bead areas 2, the carcass ply 10 has a section 10a, which runs between sections 9a and 9b of the carcass ply 9 and is in contact with these sections 9a and 9b. Within the bead areas 2, the carcass ply 10 extends with a terminal section 10b between the core profiles 4 and the bead cores 3, in contact with these and with section 9b of the carcass ply 9. The sections 10b terminate externally, axially laterally to the bead cores 3, in particular laterally to the beginning of the fold section 9d of the carcass ply 9.

[0021] At the in Fig. 2 In the illustrated embodiment, the arrangement and course of the carcass layer 10 corresponds to that of the embodiment according to Fig. 1The first carcass layer 9' runs analogously to the first embodiment with a section 9'a continuously between both bead areas 2, surrounds the bead cores 3 with folding sections 9'd from the inside out and finally ends towards the side wall 5 as a usual upturn 9'b.

[0022] Figs. 3 to 7 show successive assembly steps in the construction of a tire carcass according to Fig. 1The figures show the assembly of a vehicle pneumatic tire on the first stage of a tire building machine, a carcass machine. The figures each show parts of an expanding carcass drum 11 having a cylindrical outer circumference and two expandable bellows carriers 12 arranged laterally to the carcass drum 11, each with inflatable bellows 13. The vertical dashed line m indicates the plane of symmetry of the carcass drum 11, and the dashed line a indicates the axis of the carcass drum 11; that is, below line a and mirrored to it are the second halves of the carcass drum 11, the bellows carriers 12, and the bellows 13 (not shown).

[0023] In the Fig. 3In the position shown, the outer surfaces of the uninflated bellows 13, together with the outer surface of the carcass drum 11, form an essentially uniform cylindrical bearing surface. The inner layer 8 – a layer of a rubber compound – and then the carcass layer 9 are first placed onto this bearing surface with overhangs on the bellows 13 and subsequently connected or spliced ​​together by overlapping their end sections. The two bellows supports 12 are then slightly retracted, so that the outer diameters of the bellows 13 decrease relative to the outer diameter of the carcass drum 10. Fig. 4 ). Now the bead cores 3 together with the core profiles 4, which were produced as "core packages", are placed on the protrusions at the now set-off shoulder areas of the carcass layer 9 ( Fig. 5 ) and rolled laterally against the carcass layer 9 ( Fig. 6). Subsequently, the carcass layer 10 is placed on top of the carcass layer 9 and the core packages from the outside ( Fig. 6 ), overlapping spliced ​​and their sections located laterally to the core packages are attached to the core packages by rolling. By inflating the bellows 13, the lateral overhangs of the carcass ply 9 are folded over along the carcass ply 10 ( Fig. 7 By setting sidewall profiles, the tire carcass is assembled in a known manner, removed from the carcass machine, transferred to the second stage of the tire building machine and assembled here into a raw tire by adding the belt and the tread. Reference symbol list

[0024] 1 Tread 2 Bead area 3 Bead core 4 Core profile 5 Sidewall 6 Belt 6a, 6b Belt layer 7 Belt bandage 8 Inner layer 9, 9' First carcass layer 9a, 9b, 9'a Section 9'b High edge 9c End section 9d, 9'd Fold section 10 Second carcass layer 10a Section 10b End section 11 Carcass drum 12 Bellows support 13 Bellows 14 Horn profile a Axis b Width m Plane of symmetry

Claims

1. Pneumatic vehicle tyre having a profiled tread (1), a belt (6) having at least two plies (6a, 6b), an inner layer (8), bead regions (2) having bead cores (3) and core profiles (4), a carcass inlay having a first carcass ply (9, 9') and a second carcass ply (10), wherein the first carcass ply (9, 9') has a portion (9a, 9'a) running continuously from bead region (2) to bead region (2) and along the inner layer (8), bent-over portions (9d, 9'd) running in the axial direction on the bead cores (3) and further portions (9b, 9'b) running on the outside in the bead regions (2), and wherein the second carcass ply (10) has a continuous portion (10a) that is in contact with the first carcass ply (9, 9'), runs from bead region (2) to bead region (2) and ends in the bead regions (2), wherein, in the bead regions (2), the second carcass ply (10) runs between the first carcass ply (9, 9') on one side and the core profiles (4) on the other side and in contact with these components, characterized in that the second carcass ply (10) ends on the outer side of the bead cores (3) and in contact with the bead cores (3).

2. Pneumatic vehicle tyre according to Claim 1, characterized in that the second carcass ply (10) in each case ends to the side of the beginning of the bent-over portion (9d, 9'd) of the first carcass ply (9, 9').

3. Pneumatic vehicle tyre according to Claim 1 or 2, characterized in that the portions (9b) of the first carcass ply (9) running on the outside in the bead regions (2) run along the second carcass ply (10) as far as a region radially on the inside of the radially inner belt ply (6b), so that the radially inner belt ply (6b) overlaps with end portions (9c) of the first carcass ply (9).

4. Pneumatic vehicle tyre according to Claim 1 or 2, characterized in that the portions (9'b) of the first carcass ply (9') running on the outside in the bead regions (2) in each case end as a turn-up (9'b) towards the sidewalls (5).

5. Method for building up a tyre carcass of a pneumatic vehicle tyre on a carcass machine having an expandable carcass drum (11) and two expandable bladder supports (12), which are arranged to the side of the carcass drum (11) and have inflatable bladders (13), the method comprising the following successive steps: a) expanding the bladder supports (12), so that the outer surfaces of the uninflated bladders (13) form, together with the outer surface of the expanded carcass drum (11), a uniform cylindrical bearing surface, b) applying an inner layer (8) and a first carcass ply (9, 9'), which projects beyond the side of the carcass drum (11), to the carcass drum (11), c) retracting the two bladder supports (12), so that the outer diameters of the bladders (13) decrease with respect to the outer diameter of the carcass drum (11) and the projections of the first carcass ply (9, 9') run along shoulders of the carcass drum (11), d) placing core assemblies of bead cores (3) and core profiles (4) onto the lateral projections of the first carcass ply (9, 9') on the shoulders of the carcass drum (11), e) rolling the core assemblies onto the side of the carcass ply (9, 9'), f) placing a second carcass ply (10), which has such a width that it extends to the side of the core assemblies at least as far as the region to the side of the bead cores (3), at most as far as the projections of the first carcass ply (9, 9'), g) rolling the second carcass ply (10) onto the core assemblies, h) inflating the bladders (13) to turn over the lateral projections of the first carcass ply (9, 9') along the core assemblies and the second carcass ply (10), i) completing the tyre carcass in a known manner.