Vehicle tires

Abstract

The invention relates to a vehicle tire comprising a tread, shoulder sections, sidewall sections and bead sections (5), wherein each bead section (5) has at least two bead cores (6.i) each made of a bead wire (7.i) wound in several layers (8) and in a circumferential ring shape, wherein the at least two bead cores (6.i) lie next to each other and spaced apart from each other in the axial direction (X) and wherein each of the at least two bead cores (6.i) is encased by a carcass insert (9.i) made of carcass cords running parallel to each other, wherein the carcass cords each run at a cord angle of between 30° and 40° relative to the circumferential direction between the two bead sections (5). According to the invention, the bead wire (7.i) is wound inside the respective bead core (6.i) in such a way that the respective bead core (6.i) has a substantially octagonal cross-section.

Description

[0001] The invention relates to a vehicle tire according to the preamble of claim 1.

[0002] Conventional vehicle tires can be manufactured in either a bias-ply or radial construction, depending on their load-bearing capacity and application. In bias-ply tires, high stability can be achieved through a specific arrangement of carcass cords in at least one carcass ply that are angled less sharply (than in radial tires) relative to the circumferential direction, as well as through a bead section with at least two bead cores.

[0003] The cross-section of the respective bead cores within the bead sections is typically rectangular or, in some cases, hexagonal, as described, for example, in CN 101072693 B. Within the bead cores, particularly in the case of a hexagonal cross-section, a bead wire is wound in multiple turns to achieve better structural integrity due to the smaller splice area and the associated stress peaks or force peaks. By using only one wound bead wire, the number of stress peaks or force peaks on adjacent components of the vehicle tire is minimized, thus largely preventing damage to these adjacent components.

[0004] Nevertheless, a bead core with a hexagonal or rectangular cross-section can still lead to high forces or stress peaks at the corners or edges of the hexagon or rectangle, which can cause fractures in the carcass cords of the carcass ply at the transitions to the adjacent carcass ply that wraps around the bead core. Other adjacent components of the bias-ply tire, for example, a neighboring bead core in a bead section with two bead cores, can also be damaged by such force or stress peaks due to the "sharp" edges.

[0005] US 2024 034 101 A1 further describes that for radial tires with a single bead core per bead section and carcass cords angled more sharply, up to 90°, relative to the circumferential direction, which are subject to different loads and have different stability requirements, a cross-section of the bead cores is provided in an approximately octagonal shape.

[0006] US patents 2020 094 505 A1, US 5'989'374 A, JP 2008254398 A, US 9'138'952 B2, CN 216374079 U, JP-H-09254611 A, JP 4615653 B2, and CN 217532427 U also describe radial tire construction with only one wound bead core per bead section and with an approximately octagonal cross-section of the bead core. These radial tires are subject to different loads than bias-ply tires and are also subject to different stability requirements, particularly in the bead section. US patent 4406317A further describes rounding the edges of the bead cores, which, however, is a complex process.

[0007] The following invention is based on the objective of providing a diagonally constructed vehicle tire that has improved structural integrity, particularly in the bead section.

[0008] This problem is solved by a vehicle tire according to the independent claim. The dependent claims specify preferred embodiments.

[0009] According to the invention, a vehicle tire is provided with a circumferential tread that extends on both sides of a tire zenith, wherein the tread transitions axially on both sides via a shoulder section into a sidewall section of the vehicle tire and the respective sidewall section extends radially inwards to a bead section of the vehicle tire. wherein each bead section has at least two bead cores, each consisting of a bead wire of a certain thickness wound in several layers and circumferentially in a ring shape, wherein the at least two bead cores lie side by side and spaced apart from each other in the axial direction within the respective bead section, and wherein each of the at least two ring-shaped wound bead cores within the respective bead section is independently encircled or surrounded by at least one carcass insert made of parallel carcass cords, for example by folding the carcass cords back on themselves in a radial direction and thereby surrounding or encircling the respective bead core in a loop-like manner, wherein the carcass cords of the respective carcass ply each run at a cord angle of between 30° and 40°, preferably 35°, relative to the circumferential direction over the two sidewall sections, the shoulder sections and the tread strip between the two bead sections, so that a diagonal tire is formed, wherein the bead wire within the respective bead core is wound in a ring-like circumferential fashion in the several layers such that the respective bead core has a substantially octagonal cross-section exhibits. This means that each wound bead wire is surrounded by a body in the form of an octagon, i.e., the bead wire is located completely inside this octagon and defines the shape and extent of this octagon through its outer contour.

[0010] The invention achieves the advantage that fewer stress peaks or force peaks act on the carcass cords, which are angled relative to the circumferential direction and thus also relative to the circumferentially wound bead wire, because the cross-section of the bead core, in this case with eight corners, is closer to the shape of a circular bead core. In contrast to a rectangle or hexagon, as in the prior art for bias-ply tires, the corners of the octagon are less acute and enclose a larger internal angle. The carcass cords resting on it at the cord angle are therefore subjected to a lower point load, as the force is distributed across the multiple and less acute corners of the octagon. This reduces the risk of carcass cord breakage and increases the durability and reliability of the vehicle tire. The octagonal shape of the bead core thus allows for a balance or...A compromise is achieved between simple manufacturing and the impact on surrounding tire components.

[0011] In particular, the adjacent and spaced bead core, which provides additional stability within the same bead section of a bias-ply tire, can be better protected by the octagonal shape of the bead core. Accordingly, the adjacent bead cores can be aligned so that their respective sides of the octagon lie parallel to each other, or side by side in such a way that the corners of adjacent bead cores do not pinch the intervening carcass plies at specific points. This prevents localized forces and stress concentrations on both the carcass plies and the bead cores. Therefore, the risk of breakage of the bead cores themselves and the carcass plies is reduced, and the durability and reliability of the vehicle tire are increased.

[0012] According to a further embodiment, the bead wire within the respective bead core comprises a bead wire core, preferably made of steel, and a bead wire sheathing made of a rubber material surrounding the bead wire core. In this way, additional stress peaks can be cushioned, since these can be at least partially absorbed by the softer bead wire sheathing, and this bead wire sheathing can also at least partially adapt to the adjacent surface.

[0013] Preferably, the respective bead core is further defined radially outward by a top surface, radially inward by a bottom surface, axially inward by an inner surface, and axially outward by an outer surface. These surfaces, together with connecting surfaces, define the octagon that encloses the wound bead wire of the bead core. The bead core height is measured between the top and bottom surfaces, and the bead core width between the inner and outer surfaces. Depending on the type (load, size, application, etc.) of the vehicle tire, the bead core height and width may, for example, be between 14 mm and 22 mm. The cross-section of the respective bead core can thus be clearly defined by appropriate lines or boundaries.

[0014] Preferably, the upper surface length and / or the lower surface length are, for example, between 25% and 80%, preferably between 45% and 80%, of the bead core width, and the inner surface length and / or the outer surface length are between 25% and 75%, preferably between 30% and 60%, of the bead core height. It is also possible for the upper surface length and the lower surface length to be different, or for the inner surface length and the outer surface length to be different.

[0015] Within the octagonal shape, the cross-sectional geometry can be flexibly adapted to the type of vehicle tire, particularly to the intended load or stability requirements. In this regard, it is preferably also possible to provide that the bead core height and the bead core width of the respective bead core have an aspect ratio between 1:0.8 and 1:1.2 (H6:B6). Therefore, an aspect ratio can also be specifically adapted to the construction of the respective diagonal-ply vehicle tire, and in particular to the construction of the respective bead section with its at least two cores.

[0016] Preferably, the top and bottom surfaces are parallel to each other and parallel to the axial direction, and / or the inside and outside surfaces are parallel to each other and parallel to the radial direction. This allows for simple production of the wound bead core, as the bead core is produced layer by layer in the radial direction, with each layer being built up axially by a corresponding winding. In this way, the at least two bead cores per bead section can be arranged axially next to each other with a sufficiently large overlap, without the corners causing stress concentrations on the adjacent bead core. The positioning of the at least two bead cores within the bead section can therefore be optimized.

[0017] Preferably, the bead wire is wound within the respective bead core with between 55 and 80 turns, and radially overlapping layers within the bead core are offset from each other by half the wire thickness of the bead wire. This ensures optimal stacking of the individual layers, resulting in good stability and strength of the bead core.

[0018] Preferably, the wire thickness of the bead wire is between 1.5 mm and 2 mm, wherein the bead wire core is, for example, at least 1.2 mm thick and the bead wire sheath is, for example, between 0.1 mm and 0.3 mm thick. With such thicknesses, good stability and an approximately octagonal shape can be achieved.

[0019] Preferably, the at least two bead cores each have a bead wire with identical wire thickness. In this way, the adjacent bead cores with the octagonal shape can be optimally arranged within the same bead section without interfering with each other.

[0020] Preferably, the carcass cords of the respective carcass insert preferably run approximately parallel to each other and each have a cord core, for example made of textile, in particular polyamide or polyester, which is surrounded by a cord sheath, for example made of a rubber material. In this way, the carcass cords that are wrapped around the bead cores can be additionally protected, since the cord sheath, due to its low stiffness, can adapt to the corners of the octagonal bead cores. The remaining angularity of the bead cores can thus be at least partially compensated for by this cord sheath made of the rubber material and, depending on the design, also by the bead wire sheath made of the rubber material, which thus complement each other.

[0021] Additionally, it can be provided that in each bead section, a circumferentially ring-shaped bead flap runs radially between the respective bead cores and the carcass cords of the respective carcass insert. This allows any remaining stress peaks between the carcass cords and the bead cores to be absorbed.

[0022] Preferably, it is further provided that the core diameter of the cord cores is between 1.5mm and 1.7mm, preferably 1.6mm, and the sheathing thickness of the cord sheathing is between 0.15mm and 0.25mm, preferably 0.2mm.

[0023] The drawings show: Fig. 1 a vehicle tire in cross-section; Fig. 2 a detailed view of a bead section of the vehicle tire according to Fig. 1; Fig. 3 a detailed view of the carcass insert of the vehicle tire according to Fig. 1; and Fig. 4A-4G different octagonal cross-sections of the bead cores in the bead section according to Fig. 2.

[0024] Fig. Figure 1 shows a cross-sectional view of a vehicle tire 1, which has a circumferential tread 2 extending on both sides over the tire's apex Z. The tread 2 transitions axially X and laterally on both sides via a shoulder section 3 into a sidewall section 4, which extends radially R inwards to a bead section 5, so that a bead section 5 is located on both sides of the tire's apex Z.

[0025] Within each bead section 5 are as in Fig. 2. An example shows a number N (N=3 in Fig. 1 and Fig. 2) provided on bead cores 6.i, with i = 1, 2,... N, wherein the number N is at least two. The at least two bead cores 6.i are spaced apart from each other in the axial direction X within the respective bead section. Each bead core 6.i is formed by winding a bead wire 7.i, with i = 1, 2,... N, in a ring shape, so that several layers 8 extending in the axial direction X are formed around the circumference of the respective bead core 6.i, which lie one above the other in the radial direction R. The wound bead wire 7.i runs in radially superimposed layers 8 offset by half a wire thickness D7.i of the respective bead wire 7.i, i.e., the windings within a layer 8 are "chambered" in the spaces between the windings in a radially below (radially inwards) or radially above (radially outwards) layer 8.

[0026] In the respective bead sections 5, the bead cores 6.i are each surrounded by at least one carcass insert 9.i, wherein a carcass insert central region 9a of the respective carcass insert 9.i lies at the tire zenith Z of the vehicle tire 1 and extends from there axially X to both sides and radially R across the respective sidewall sections 4 into the respective bead section 5. The respective carcass insert 9.i thus extends continuously between the two bead sections 5. In the embodiment in Fig. 1 and Fig. 2. With the number N = 3 shown, three superimposed carcass inserts 9.1, 9.2, 9.3 are also provided.

[0027] In the two bead sections 5, the respective carcass insert 9.i is folded from axially inwards to axially outwards around the respective associated bead core 6.i and folded back onto itself, so that the bead cores 6.i in the respective bead section 5 are enveloped by the respective associated carcass insert 9.i. The carcass insert center section 9a of the respective carcass insert 9.i transitions in the respective bead section 5 into a carcass insert end section 9b, which, as a folded-over area of ​​the respective carcass insert 9.i, is again directed radially outwards towards the respective sidewall sections 4.

[0028] The respective carcass insert 9.i is as described in Fig. Figure 3 schematically represents the formation of several carcass cords 10, which run approximately parallel to each other and each have a cord core 10a made of textile, for example polyamide or polyester, which is surrounded by a cord sheath 10b made of a rubber material or a rubber compound, wherein preferably an adhesive system is provided between the cord sheath 10b and the cord core 10a. In the cured state of the vehicle tire 1, the carcass cords 10 run at a cord angle 10c of between 30° and 40°, preferably 35°, to the circumferential direction U. Consequently, the vehicle tire 1 is a bias-ply tire. The core diameter 10d of the cord cores 10a is preferably between 1.5mm and 1.7mm, preferably 1.6mm, and the sheathing thickness 10e of the cord sheathing 10b is between 0.15mm and 0.25mm, preferably 0.2mm, so that the cord thickness 10f of the carcass cords 10 is between 1.8mm and 2.2mm.

[0029] Additionally, the presentation shows that Fig. 1 and Fig. 2 a bead flap 11 (flipper) is provided, which is located radially below (radially inside) the bead cores 6.i in the respective bead section 5 between these and the carcass cords 10 of the respective carcass insert 9.i.

[0030] As shown in the sectional views in the Fig. 4A, Fig. 4B, Fig. 4C, Fig. 4D, Fig. 4E, Fig. 4F, Fig. As shown in Figure 4G, the bead cores 6.i in the respective bead section 5 can have different cross-sections. In each embodiment, however, the respective bead core 6.i is provided to have an approximately octagonal cross-section, i.e., the windings of the respective bead wire 7.i are enclosed in the axial direction X and radial direction R by a polygon with eight vertices E. Such an octagon O enclosing the respective bead core 6.i is bounded by a top surface 12a, which limits the respective bead core 6.i radially outward, a bottom surface 12b, which limits the respective bead core 6.i radially inward, an inner surface 12c, which limits the respective bead core 6.i axially inward, and an outer surface 12d, which limits the respective bead core 6.i axially outward. Furthermore, connecting sides 12e run between the inner side 12c and the upper side 12a or the lower side 12b, as well as between the outer side 12b and the upper side 12a or the lower side 12b.subpage 12b, as shown.

[0031] The upper surface 12a and the lower surface 12b preferably run approximately parallel to each other and parallel to the axial direction X, and the inner surface 12c and the outer surface 12d preferably run approximately parallel to each other and parallel to the radial direction R. The connecting sides 12e run at a corresponding angle to these, preferably such that the respective bead core 6.i is enclosed by a symmetrically designed octagon O.

[0032] The bead core height H6 (in the radial direction R) of the respective bead core 6.i is determined by a distance between the top surface 12a and the bottom surface 12b, and the bead core width B6 (in the axial direction X) by a distance between the inner surface 12c and the outer surface 12d. The proportions of the top surface 12a and the bottom surface 12b to the bead core width B6 can vary, with a top surface length L12a and a bottom surface length L12b, for example, being between 25% (longer connecting sides 12e) and 80% (shorter connecting sides 12e), preferably between 45% and 80%, of the bead core width B6. Similarly, an inner side length L12c or an outer side length L12d can be between 25% and 75%, preferably between 30% and 60%, of the bead core height H6. Fig. 4A and Fig. Section 4B shows exemplary cross-sections with different percentage values. It is also possible that the top side length L12a and the bottom side length L12b are different, or that the inside side length L12c and the outside side length L12d are different.

[0033] Furthermore, the bead core height H6 and the bead core width B6 of a bead core 6.i can be in an aspect ratio of between 1:0.8 and 1:1.125 (H6:B6) in order to adapt the cross-sectional shape to different loads in the vehicle tire 1, to different stability requirements, or to a specific tire size. In the Fig. Figures 4C to 4G are examples of octagonal cross-sections with different aspect ratios.

[0034] To achieve such aspect ratios, the following layer sequences can be chosen within a bead core 6.i, for example: 7-8-9-8-9-8-9-8-7 windings in the respective layer 8 (from the top 12a to the bottom 12b, as in Fig. (shown in Figure 4C), resulting in a total of 73 windings within the bead core 6.i with an aspect ratio of 1:1.125 (H6:B6). Alternatively, as shown in Fig. The following sequence of layers 8 is shown in 4D: 5-6-7-6-7-6-7-6-5-4 windings in the respective layer 8, so that a total of 59 windings are present within the bead core 6.i with an aspect ratio of 1:0.8 (H6:B6).

[0035] According to the further alternative in Fig. 4E uses a 7-8-9-8-9-8-7-6-5-4 sequence with a total of 71 windings to achieve an aspect ratio of 1:1.02 (H6:B6). Fig. 4F uses a 7-8-9-9-9-9-9-8-7 sequence with a total of 76 windings to achieve an aspect ratio of 1:1.2 (H6:B6). Fig. 4G is a 5-6-7-7-7-7-7-6-5-4 sequence with a total of 61 windings designed to achieve an aspect ratio of 1:0.85 (H6:B6).

[0036] The number of windings is determined primarily based on the load on the respective vehicle tire 1, the stability requirements, and the tire size. The wire thickness D7.i of the respective bead wire 7.i can also play a role. For example, the bead wire 7.i can have a wire thickness D7.i of between 1.5 mm and 2 mm, and can also consist of a steel bead wire core 7a and a rubber wire sheath 7b.

[0037] According to the descriptions in the Fig. 1 and Fig.2. Three bead cores 6.i within a bead section 5 are arranged axially adjacent to one another such that the inner surfaces 12c and the outer surfaces 12d of adjacent octagonal bead cores 6.i are approximately parallel to each other. The respective carcass inserts 9.i run between them. The inner surfaces 12c and the outer surfaces 12d of adjacent octagonal bead cores 6.i can completely overlap or be offset from each other. Due to this approximately parallel arrangement, two adjacent carcass inserts 9.i are not pinched at two points between the corners E of adjacent bead cores 6.i in the axial direction X. Rather, approximately the same forces act on the intervening carcass inserts 9.i over the entire area. This avoids peak forces or loads, thereby increasing the durability of the bead cores 6.i and also the carcass inserts 9.i.

[0038] Accordingly, the respective bead cores 6.i, due to their octagonal cross-section, at least approximate the rounded shape of the carcass cords 10. The corners E or edges between the respective sides 12a, 12b, 12c, 12d are also less pronounced due to the octagonal construction O, thus reducing the peak forces or loads on the carcass cords 10. This, in turn, increases the durability of the carcass cords 10 while maintaining the stability of the bead cores 6.i. This is further optimized by the bead wire sheath 7b of the respective bead wire 7.i, which is made of a rubber compound and is less rigid than the steel bead wire core 7a. Additional forces can be absorbed via the bead flap 11. Reference symbol list 1 vehicle tire 2 treads 3 Shoulder section 4 Side wall section 5 bead section 6.i i. bead core 7.i i. Bead wire 7a Bead wire core 7b Bead wire sheathing 8 layers 9.i i. Carcass insert 9a Carcass inserts - central area 9b Carcass insert end area 10 Carcass cords 10a Cord core 10b Cord sheathing 10c Cord angle 10d core diameter 10e sheathing thickness 10f cord thickness 11. Bulge flag 12a Top 12b Underside 12c inside 12d outside 12e Connection page B6 bead core width D7.i Wire thickness of the i. bead wire E corner H6 bead core height i Index L12a Top side length L12b Subpage length L12c Inside length L12d outer side length N number O Octagon R radial direction U circumferential direction X axial direction Z Tire zenith QUOTES INCLUDED IN THE DESCRIPTION

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

[0000] CN 101072693 B

[0003] US 2024 034 101 A1

[0005] US 2020 094 505 A1

[0006] US 5,989,374 A

[0006] JP 2008254398 A

[0006] US 9'138'952 B2

[0006] CN 216374079 U

[0006] JP-H-09254611 A

[0006] JP 4615653 B2

[0006] CN 217532427 U

[0006] US 4406317A

[0006]

Claims

[1] Vehicle tire (1), with a circumferential tread (2) extending on both sides of a tire zenith (Z) of the vehicle tire (1), wherein the tread (2) transitions in the axial direction (X) on both sides over a shoulder section (3) into a sidewall section (4) and the respective sidewall section (4) extends in the radial direction (R) inwards to a bead section (5) of the vehicle tire (1), wherein each bead section (5) has at least two bead cores (6.i) each made of a bead wire (7.i) of a wire thickness (D7.i) wound in several layers (8) and in a ring-shaped manner in the circumferential direction (U), wherein the at least two bead cores (6.i) lie next to each other and spaced apart from each other in the axial direction (X) within the respective bead section (5), and wherein each of the at least two bead cores (6.i) within the respective bead section (5) is independently encircled by at least one carcass insert (9.i) made of carcass cords (10) running parallel to each other, wherein the carcass cords (10) of the respective carcass insert (9.i) each run at a cord angle (10c) of between 30° and 40° relative to the circumferential direction (U) between the two bead sections (5), characterized by , that the bead wire (7.i) is wound inside the respective bead core (6.i) in such a way that the respective bead core (6.i) has a substantially octagonal cross-section. [2] Vehicle tires (1) according to claim 1, characterized by , that the bead wire (7.i) within the respective bead core (6.i) comprises a bead wire core (7a), preferably made of steel, and a bead wire sheath (7b) surrounding the bead wire core (7a) made of a rubber material. [3] Vehicle tires (1) according to claim 1 or 2, characterized by , that the respective bead core (6.i) is bounded radially outward by a top surface (12a), radially inward by a bottom surface (12b), axially inward by an inner surface (12c) and axially outward by an outer surface (12d), which together with connecting surfaces (12e) define an octagon (O) that surrounds the wound bead wire (7.i) of the bead core (6.i), wherein a bead core height (H6) is measured between the top (12a) and the bottom (12b) and a bead core width (B6) is measured between the inside (12c) and the outside (12d). [4] Vehicle tires (1) according to claim 3, characterized by , that a top side length (L12a) of the top side (12a) and / or a bottom side length (L12b) of the bottom side (12b) is, for example, between 25% and 80%, preferably between 45% and 80%, of the bead core width (B6), and an inside side length (L12c) of the inside side (12c) and / or an outside side length (L12d) of the outside side (12d) is between 25% and 75%, preferably between 30% and 60%, of the bead core height (H6). [5] Vehicle tires (1) according to claim 3 or 4, characterized by , that the bead core height (H6) and the bead core width (B6) of the respective bead core (6.i) are in an aspect ratio of between 1:0.8 and 1:1.2 (H6:B6). [6] Vehicle tires (1) according to any one of claims 3 to 5, characterized by , that the top (12a) and the bottom (12b) run parallel to each other and parallel to the axial direction (X) and / or the inside (12c) and the outside (12d) run parallel to each other and parallel to the radial direction (R). [7] Vehicle tires (1) according to any one of claims 3 to 6, characterized by , that the bead wire (7.i) is wound within the respective bead core (6.i) with between 55 and 80 turns and that in radial direction (R) superimposed layers (8) are offset from each other by half the wire thickness (D7.i) of the bead wire (7.i). [8] Vehicle tires (1) according to any one of the preceding claims, characterized by , that the wire thickness (D7.i) of the bead wire (7.i) is between 1.5mm and 2mm. [9] Vehicle tires (1) according to any one of the preceding claims, characterized bythat the at least two bead cores (6.i) each have a bead wire (7.i) with identical wire thickness (D7.i). [10] Vehicle tires (1) according to any one of the preceding claims, characterized by , that in the respective bead section (5) in radial direction (R) between the respective bead cores (6.i) and the carcass cords (10) of the respective carcass insert (9.i) a circumferentially circumferential bead flap (11) runs in circumferential direction (U). [11] Vehicle tires (1) according to any one of the preceding claims, characterized by , that the carcass cords (10) of the respective carcass insert (9.i) preferably run approximately parallel to each other and each have a cord core (10a), for example made of textile, in particular of polyamide or polyester, which is surrounded by a cord sheath (10b), for example made of a rubber material. [12] Vehicle tires (1) according to claim 11, characterized by, that the core diameter (10d) of the cord cores (10a) is between 1.5mm and 1.7mm, preferably 1.6mm, and the sheathing thickness (10e) of the cord sheathing (10b) is between 0.15mm and 0.25mm, preferably 0.2mm.

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