VEHICLE TIRES AND VEHICLE WHEEL

Description

[0001] The invention relates to a vehicle pneumatic tire with a tread and two sidewalls terminating in bead areas, as well as a carcass extending radially below the tread and along the sidewalls and encircling the bead areas, wherein the bead areas comprise a core and an apex extending radially outwards from the core, and the vehicle pneumatic tire is suitable for mounting on a rim with a curved rim flange area.

[0002] Pneumatic tires of the type mentioned above are well-known and are manufactured in a wide variety of designs for passenger cars and vans, for example. In particular, pneumatic tires with high load capacities and correspondingly high load-bearing capacities, such as those used in commercial vans, are often equipped with reinforcing elements in the bead area to accommodate the increased stress. These can be, for example, fabric strips that form an angled connection with the carcass. Additional carcass layers in the bead area and the arrangement of thick rubber components in the bead are also known. As a result, movement of the pneumatic tire in the bead area is reduced, and its durability is improved. Furthermore, special sidewall constructions are known to increase the tire's robustness.However, the use of reinforcing elements, especially in the form of stiffer materials, thicker padding and more elaborate constructions, always comes with disadvantages in rolling resistance, comfort and higher material costs.

[0003] From JP 2016 078564 A, a vehicle pneumatic tire with an outer apex is known, which has a complex modulus of elasticity of 15-75 MPa.

[0004] Further embodiments of vehicle pneumatic tires with an outer apex are the subject of JP 2007 045 333 A, JP 2004 182021 A, JP 2018 095135 A and WO 2021 / 149388 A1.

[0005] The object of the invention is therefore to propose a vehicle pneumatic tire of the type mentioned above which, with significantly improved rolling resistance, has a significantly higher bead durability and corresponding load-bearing capacity, for example for applications in the van sector.

[0006] To solve the problem posed, the invention proposes the design of a vehicle pneumatic tire according to the features of claim 1.

[0007] Advantageous embodiments and further developments of the invention are the subject of the dependent claims.

[0008] According to the invention, it is proposed that an outer apex formed from a rubber strip with a Shore hardness A according to ASTM D 2240 of 60 to 88 and a dynamic modulus of elasticity of 8 to 12 N / mm² and a rebound elasticity according to YOUR 53512 is arranged from 60 to 85% at room temperature and from 65 to 90% at a temperature of 70°C.

[0009] The outer apex arranged axially adjacent to the apex in the side wall according to the invention is optimized due to the selected mechanical properties of the rubber material used, especially with regard to the conflicting objectives of stiffness / durability / hysteresis losses, and offers a significantly improved rolling resistance while maintaining the desired high load-bearing capacity, overload capacity, robustness and bead durability.

[0010] The inventive design of the outer apex arranged in the sidewall results in a multi-layered sidewall structure characterized by significantly altered properties depending on the requirements profile of the vehicle tire. For example, the outer apex can exhibit increased stiffness compared to the sidewall material, thus providing particularly high support in the bead area. Furthermore, depending on the properties of the rubber material used for its formation, the outer apex can exhibit lower hysteresis and improve the rolling resistance of the vehicle tire.

[0011] Preferably, a rubber strip with a Shore A hardness according to ASTM D 2240 of 68 to 78 and a dynamic modulus of 9 to 11 N / mm² and a rebound elasticity according to DIN 53512 of 68 to 78% at room temperature and of 71 to 83% at a temperature of 70°C is provided for the formation of the outer apex.

[0012] According to a proposal of the invention, the outer apex has, to optimize the strength properties, a tensile strength according to DIN 53504 of 3.5 to 10 N / mm² and an elongation at break according to DIN 53504 of 60 to 200% at room temperature, and a tensile strength according to DIN 53504 of 3 to 8 N / mm² and an elongation at break according to DIN 53504 of 45 to 190% at a temperature of 70 °C. Preferably, a tensile strength according to DIN 53504 of 4.5 to 8 N / mm² and an elongation at break according to DIN 53504 of 70 to 150% are provided, each at room temperature, and a tensile strength according to DIN 53504 of 4 to 7 N / mm² and an elongation at break according to DIN 53504 of 80 to 120% are provided, each at a temperature of 70 °C.

[0013] Furthermore, another proposal of the invention provides that the outer apex has an energy density at room temperature of 1.5 to 5 J / cm 3< , preferably 2 to 3.5 J / cm 3< , and at a temperature of 70 °C an energy density at break according to DIN 53504 of 1 to 5 J / cm 3< , preferably 1.5 to 3.2 J / cm 3< .

[0014] According to a further proposal of the invention, the outer apex in the mounted state of the vehicle pneumatic tire on the rim is arranged at least partially in a radial direction above the rim flange area in the sidewall in order to modify the sidewall area locally where the highest forces are to be expected.

[0015] According to a further proposal of the invention, the sidewalls of the vehicle pneumatic tire according to the invention can be made of a rubber material with a Shore A hardness according to ASTM D 2240 of 40 to 60, preferably 45 to 55, and a dynamic modulus of elasticity of 3 to 6 N / mm², preferably 4 to 5 N / mm², as well as a rebound elasticity according to DIN 53512 of 45 to 75%, preferably 50 to 67% at room temperature and a tensile strength according to DIN 53504 of 6 to 15 N / mm², preferably 8 to 13 N / mm², and an elongation at break according to YOUR 53504 of 400 to 600%, preferably 450 to 550%, each formed at room temperature.

[0016] According to a further aspect of the invention, a rim strip, a so-called rim strip, can be provided radially below the bead area and towards the rim, extending into the sidewall. According to the invention, this rim strip is made of a rubber material with a Shore A hardness according to ASTM D 2240 of 65 to 85, preferably 70 to 80, and a rebound elasticity according to DIN 53512 of 34 to 65%, preferably 36 to 60% at room temperature and 50 to 70%, preferably 55 to 70% at a temperature of 70 °C, as well as a tear strength according to YOUR 53504 of 10 to 16 N / mm², preferably 11 to 14 N / mm² and an elongation at break according to YOUR 53504 of 160 to 275%, preferably 170 to 260%, each at room temperature.

[0017] The invention further proposes that, to further reinforce the sidewall areas, the carcass, with its end that wraps around the bead area, projects beyond the radially outer end of the apex and the outer apex of the vehicle tire in the radial direction. It is understood that further carcass layers may also be provided between the apex and the outer apex.

[0018] A further increase in sidewall stability with low rolling resistance is achieved by forming, according to a further proposal of the invention, a bead lip projecting over the circumference of at least one sidewall and / or the rim strip axially on the outside, which has a bead lip surface which, in the mounted state of the vehicle pneumatic tire on the rim, is intended to bear on the curved rim flange area.

[0019] The bead lip, which rests on the rim flange, provides positive support for the sidewall area at the transition to the bead area on the rim flange. Simultaneously, this area of ​​the sidewall is reinforced and / or its properties are modified by the integrated outer apex. As a result, the sidewall exhibits increased strength and support, eliminating the need for the typically used reinforcing fabric strips to enhance load-bearing capacity. This reduces disadvantages related to rolling resistance and material costs without compromising bead durability.

[0020] According to a further proposal of the invention, the outer apex extends in the radial direction of the vehicle pneumatic tire from an area located below the bead lip to an area located above the bead lip along the sidewall and / or the rim strip in order to optimally reinforce the sidewall of the vehicle pneumatic tire in this highly stressed area.

[0021] Preferably, the bead lip of the vehicle pneumatic tire is arranged such that the bead lip surface, when the vehicle pneumatic tire is mounted on the rim, comes into contact with the rim flange area all around, with a slight press fit of the bead lip surface on the rim flange area being particularly preferred in order to ensure a reliable seal and positive support.

[0022] In particular, the bead lip surface, viewed from the outside of the tire, can be concavely curved and have a radius of curvature that is slightly smaller than the radius of curvature of the rim flange area, so that in the unmounted state an overlap is formed between the bead lip in the area of ​​the bead lip surface and the curved rim flange, which enables the desired press fit when the pneumatic tire is mounted on the rim.

[0023] The invention also relates to a vehicle wheel with a pneumatic tire mounted on a rim according to the invention, as described above.

[0024] Further embodiments and details of the invention are explained below with reference to the drawing illustrating an exemplary embodiment. The drawing shows: Figure 1 shows a schematic representation of a partial section through a vehicle pneumatic tire according to the invention; Figure 2 shows an enlarged representation of the sidewall and bead area of ​​the vehicle pneumatic tire according to the invention. Figure 1 in a first embodiment; Figure 3 an enlarged view of the sidewall and bead area of ​​the vehicle pneumatic tire according to Figure 1 in a second embodiment.

[0025] The Figure 1Figure 1 shows a partial cross-section through a radial vehicle tire 10, which has a profiled tread 1, a belt 2 consisting of two layers 2a, 2b, which is covered by a bandage 18, a radial carcass 3, an airtight inner layer 4, sidewalls 6, and the bead area 5 with cores 7 and apex 8. The sidewalls 6 terminate radially on the inside of the tread 1 in the bead areas 5. The vehicle tire 10 designed in this way is suitable for mounting on a rim 11 with a curved rim flange 12 and a rim flange radius R1 of at least 9.5 mm, see Figure 1. Figure 2 .

[0026] Optionally, a bead lip 9 is arranged axially on at least one sidewall 6 of the vehicle tire 10, extending around the circumference of the sidewall 6. This bead lip 9 projects axially from the tire's outer surface A and has a bead lip surface 13, which, in the illustrated embodiment, is designed to bear continuously around the entire circumference on the curved rim flange area 12. Viewed from the tire's outer surface A, the bead lip surface 13 is concavely curved and has a radius of curvature R2 that is smaller than the radius of curvature R1 of the rim flange area 12, i.e., the radius of curvature R2 is less than 9.5 mm. However, those skilled in the art will recognize that the vehicle tire can also be designed without a bead lip 9.

[0027] The depicted vehicle tire 10 could, for example, be a radial tire with increased load capacity and a corresponding load index for a van.

[0028] The bead lip surface 13 has a circular arc 14 with a radius of curvature R2 less than 9.5 mm, preferably a ratio R2 / 9.5 mm of about 0.57-0.82, preferably of 0.65-0.73 is provided.

[0029] The bead lip 9 provided in the area of ​​the outer side A of the tire projects axially outwards in the direction aR beyond the dashed contour of the sidewall 6 of the vehicle pneumatic tire 10 and is arranged such that, in the unmounted state, an overlap of at least the radially outer area occurs with the curved rim flange area 12, the contact surface of which runs along a circular path 14 with a radius of curvature R1 of 9.5 mm.

[0030] This overlap ensures that, in the assembled state, according to Figure 2 the bead lip 9 with its bead lip surface 13 is pressed onto the surface of the curved rim flange area 12, creating an interference fit, and insofar as the bead lip 9 is positively supported on the surface of the rim flange area 12 lying on the circular path 14.

[0031] At the same time, it can be seen in the figures that, adjacent to the bead lip 9 which is supported on the rim flange area 12 by means of a bearing, an outer apex 30 is arranged within the side wall 6, which is located in the Figure 2 The depicted mounted state of the vehicle pneumatic tire 10 on the rim 11 extends from an area located below the bead lip 9 to an area located above the bead lip 9 in the sidewall 6, when the vehicle pneumatic tire 10 is mounted as shown in Figure 2The sidewall 6 of the vehicle tire is viewed in the radial direction rR. This results in the sidewall 6 being modified in its properties, for example, reinforced, in the area of ​​the sidewall 6 that protrudes from the rim mouth enclosed between the rim flange areas 12, by the outer apex 30, depending on the material selected. In such a case, the sidewall 6 is reinforced in the area that transfers the forces absorbed by the bead lip 9 into the sidewall 6.

[0032] For this purpose, the outer apex 30 is formed from a rubber compound that has a higher stiffness than the rubber compound from which the sidewall 6 is formed. It can also be formed from a corresponding rubber compound with increased hysteresis to, for example, optimize the rolling resistance characteristics of the vehicle tire.

[0033] The Outer Apex 30 is an example made from a rubber compound with a Shore A hardness of 72.2 according to ASTM D 2240 and a dynamic modulus of elasticity of 10 N / mm² according to DIN 53513. At room temperature, this rubber compound of the Outer Apex 30 exhibits a rebound elasticity of 73% according to DIN 53512, a tensile strength of 5.5 N / mm² according to DIN 53504, an elongation at break of 109% according to DIN 53504, and an energy density at fracture of 2.6 J / cm³ according to DIN 53504. In contrast, at a temperature of 70 °C, this rubber compound exhibits a rebound elasticity according to DIN 53512 of 76.5%, a tensile strength according to DIN 53504 of 4.9 N / mm², an elongation at break according to DIN 53504 of 98%, and an energy density at break according to DIN 53504 of 2.3 J / cm³.

[0034] The side wall 6, on the other hand, is made of a rubber material which has a Shore A hardness according to ASTM D 2240 of 50 and a dynamic modulus of elasticity according to DIN 53513 of 4.4 N / mm² and exhibits a rebound elasticity according to DIN 53512 of 66% at room temperature, a tensile strength according to DIN 53504 of 8.5 N / mm², an elongation at break according to DIN 53504 of 470% and a rebound elasticity according to DIN 53512 of 68% at a temperature of 70 °C.

[0035] At least in its radially lower region, the outer apex 30 is also located adjacent to the bead area 5 formed from core 7 and apex 8.

[0036] This design gives the pneumatic tire 10 a particularly high stiffness, eliminating the need for additional reinforcing elements that were previously required. Despite its high stability and load-bearing capacity, suitable for applications such as vans, the illustrated pneumatic tire can therefore do without additional fabric reinforcements for the sidewall 6, which would negatively impact rolling resistance, comfort, and the manufacturing costs of such a pneumatic tire 10.

[0037] It goes without saying that the pneumatic tire described above is suitable not only for transporters but also for other applications, such as cars, vans and commercial vehicles including trucks.

[0038] The Figure 3 shows a difference from the embodiment of the Figure 2 modified embodiment in which the side wall 6 is not as in Figure 2It is not a single piece, but a two-piece design with a lower so-called rim strip 60, which forms another part of the sidewall 6. All other parts of the vehicle pneumatic tire 10 have the same reference numerals as in Figure 2 They are not explained again separately to avoid repetition and also consist of the aforementioned materials.

[0039] The property-modifying outer apex 30 extends radially rR next to the rim strip 60 into the area of ​​the sidewall 6 above it. The carcass 3, with its end 300 which wraps around the bead area, is arranged radially rR such that it extends beyond the radially outer end of the apex 8 and the outer apex 30.

[0040] The rim strip or Rim Strip 60 consists of a rubber material with a Shore A hardness of 75 according to ASTM D 2240 and exhibits, at room temperature, a rebound elasticity of 56% according to DIN 53512, a tensile strength of 12.3 N / mm² according to DIN 53504, an elongation at break of 257% according to DIN 53504, and an energy density at fracture of 7.5 J / cm³ according to DIN 53504. At a temperature of 70 °C, the rebound elasticity according to DIN 53512 is 48.7%. Reference symbol list

[0041] 1 Tread 2 Belt 3 Carcass 4 Inner layer 5 Bead area 6 Sidewall 7 Bead core 8 Bean rider 9 Bead lip 10 Pneumatic tire 11 Rim 12 Rim flange area 13 Bead lip surface 14 Circular arc 30 Outer apex 60 Rim strip R1 Rim flange radius R2 Radius of curvature A Tire outer side I Tire inner side r Radial direction a Axial direction

Claims

1. Pneumatic vehicle tyre (10) having a tread (1), and having two side walls (6) which end in bead regions (5), and also having a carcass (3) which extends radially below the tread (1) and along the side walls (6) and wraps around the bead regions (5), wherein the bead regions (5) comprise a core (7) and an apex (8) adjoining outwards of the core (7) in a radial direction (rR), and the pneumatic vehicle tyre (10) is suitable for fitting onto a rim (11) with a curved rim flange region (12), characterized in that an outer apex (30) formed from an outer apex and having a Shore hardness A according to ASTM D 2240 of 60 to 88 and a dynamic modulus of elasticity according to DIN 53513 of 8 to 12 N / mm2 as well as a rebound resilience according to DIN 53512 of 60 to 85% at room temperature and of 65 to 90% at a temperature of 70°C is arranged in the side wall (6), axially adjacent to the apex (8).

2. Pneumatic vehicle tyre (10) according to Claim 1, characterized in that the outer apex (30) has at room temperature a tensile strength at break according to DIN 53504 of 3.5 to 10 N / mm2 and an elongation at break according to DIN 53504 of 60 to 200% and has at a temperature of 70°C a tensile strength at break according to DIN 53504 of 3 to 8 N / mm2 and an elongation at break according to DIN 53504 of 45 to 190%.

3. Pneumatic vehicle tyre (10) according to Claim 1 or 2, characterized in that the outer apex (30) has at room temperature an energy density at break according to DIN 53504 of 1.5 to 5 J / cm3 and at a temperature of 70°C an energy density at break according to DIN 53504 of 1 to 5 J / cm3.

4. Pneumatic vehicle tyre (10) according to one of Claims 1 to 3, characterized in that, in the fitted state of the pneumatic vehicle tyre (10) on the rim (11), the outer apex (30) is arranged in the side wall (6) at least partially above the rim flange region (12) in the radial direction (rR).

5. Pneumatic vehicle tyre (10) according to one of Claims 1 to 4, characterized in that the side walls (6) are formed from a rubber material having a Shore hardness A according to ASTM D 2240 of 40 to 60 and a dynamic modulus of elasticity of 3 to 6 N / mm2 as well as a rebound resilience according to DIN 53512 of 45 to 75% at room temperature and a tensile strength at break according to DIN 53504 of 6 to 15 N / mm2 and an elongation at break according to DIN 53504 of 400 to 600%.

6. Pneumatic vehicle tyre (10) according to one of Claims 1 to 5, characterized in that provision is made below the bead region (5) in the radial direction (rR) and close to the rim (11) of a rim strip (60), which transitions into the side wall (6) and is formed from a rubber material having a Shore hardness A according to ASTM D 2240 of 65 to 85 and a rebound resilience according to DIN 53512 of 34 to 65% at room temperature and 50 to 70% at a temperature of 70°C as well as a tensile strength at break according to DIN 53504 of 10 to 16 N / mm2 and an elongation at break according to DIN 53504 of 160 to 275%.

7. Pneumatic vehicle tyre according to one of Claims 1 to 6, characterized in that the carcass (3) projects beyond the radially outer end of the apex (8) and of the outer apex (30) in the radial direction (rR) of the pneumatic vehicle tyre (10) at its end (300) which wraps around the bead region (5).

8. Pneumatic vehicle tyre according to one of Claims 1 to 7, characterized in that, axially on the outside at least of a side wall (6) and / or of the rim strip (60), there is formed a bead lip (9) which encircles and projects beyond the circumference thereof and which has a bead-lip surface (13) which, in the fitted state of the pneumatic vehicle tyre (10) on the rim (11), is intended for abutment on the curved rim flange region (12).

9. Pneumatic vehicle tyre (10) according to Claim 8, characterized in that, when viewed in the radial direction (rR) of the pneumatic vehicle tyre (10), the outer apex (30) extends, along the side wall (6) and / or the rim strip (60), from a region situated below the bead lip (9) into a region situated above the bead lip (9).

10. Vehicle wheel having a pneumatic vehicle tyre (10) according to one of the preceding claims that is fitted on a rim (11).