Commercial vehicle tire

Abstract

The present invention relates to a commercial vehicle tire having a bead region, each of the bead regions having a bead core (5), a flange profile (3), and an apex (6) composed of a radially outer apex portion (6a) and a radially inner apex portion (6b) in contact with the bead core (5), the radially outer apex portion (6a) and the radially inner apex portion (6b) being different from each other in terms of their rubber materials. The object of the present invention is to solve the contradiction existing between the objectives of rolling resistance and bead durability in a considerably more advantageous manner than in the prior art. This object is achieved in that the radially inner apex portion (6b) has a cross-sectional area having a surface area (A6b) in the range of 60% to 160% of the surface area (A5) of the cross-sectional area of the bead core (5), the rubber material of the radially inner apex portion (6b) has a tensile stress at 100% elongation that is 2.00 MPa to 30.00 MPa greater than the tensile stress of the rubber material of the radially outer apex portion (6a), and the rubber material of the radially outer apex portion (6a) has a resilience at 70° C. that is 5.0 percentage points to 50.0 percentage points greater than the resilience of the rubber material of the radially inner apex portion (6b).

Description

Technical Field

[0001] The present invention relates to a commercial vehicle tire comprising a bead region each having a bead core, a two-piece apex located radially outside on the bead core, and a flange profile, and further comprising a single-layer or multi-layer carcass inlay wound around the bead core, wherein each apex is composed of a radially outer apex portion and a radially inner apex portion in contact with the bead core, the radially outer apex portion and the radially inner apex portion are each composed of a rubber material, and the rubber material of the radially outer apex portion is different from the rubber material of the radially inner apex portion.

Background Art

[0002] Commercial vehicle tires of the type described at the beginning are known, for example, from German Patent Application Publication No. 102014211525A1. The commercial vehicle tire comprises a steel cord bead reinforcement extending outside the carcass inlay, a two-piece apex in each bead region, and two reinforcing plies made of a fabric reinforcing material embedded in rubber and extending outside the steel cord bead reinforcement. The apex includes a radially outer apex portion and a radially inner apex portion. In one embodiment, the rubber material of the radially outer apex portion is different from the rubber material of the radially inner apex portion in terms of its hardness. The reinforcing ply terminates radially within the bead core and is related to a line extending axially through the rim transition point in the radial direction and reaches a height of at least 70 mm. The ends of the reinforcing ply arranged at this height are at a maximum distance of 10.0 mm from each other in the radial direction. The reinforcing ply increases the rigidity in the upper bead region and the sidewall region, and as a result, the rolling resistance of the commercial vehicle tire is reduced by 2% to 5%.

[0003] Another commercial vehicle tire of the type described at the beginning is a tapered bead seat tire and is known from the specification of German Patent Application No. 102014213240A1. The commercial vehicle tire comprises an inner layer, optionally combined with a filler profile, a carcass inlay forming a carcass turn-up in each bead region, a steel cord bead reinforcement extending outside the carcass inlay and having a portion extending outside the tire and a portion extending inside the tire, and a vertex formed from a radially outer vertex portion and a radially inner vertex portion. The rubber material of the radially outer vertex portion may be different from the rubber material of the radially inner vertex portion. Between the inner layer or filler profile and the portion of the steel cord bead reinforcement extending inside the tire and the portion adjacent thereto in the radial direction of the carcass inlay, the reinforcing ply extends into a fabric reinforcing material embedded in rubber, resulting in providing particularly high load capacity and high mileage.

[0004] Japanese Unexamined Patent Application Publication No. 2000-108616 discloses a commercial vehicle tire having a bead region with a multi-part vertex each made from at least two vertex portions. According to an exemplary embodiment, the vertex is composed of a radially inner vertex portion and a radially outer vertex portion, and the rubber material of the radially inner vertex portion has a higher hardness than the rubber material of the radially outer vertex portion. This is intended to provide good bead durability.

[0005] The design of the bead area of a commercial vehicle tire is also known to have a decisive influence on driving stability, steering behavior, suspension comfort, and the fit of the tire on the rim. In this case, it is particularly important to avoid fluctuations in rigidity in the bead area and to ensure the smoothest possible transition in rigidity. The rigidity is highest in the area of the bead core, which is involved in the secure and firm fitting of the tire to the rim. In the sidewall area with a thinner design, the rigidity is lower than in the vicinity of the bead core, and as a result, the tire can be periodically compressed during rolling (bending). Excessive compression leads to greater bending and thus to heat generation, and as a result, the tire can be damaged. The rigidity and the transition in rigidity in the bead area and the sidewall area are affected by the apex. In this case, the compression should not occur too close to the rim flange of the rim, because this increases the risk that the rim flange of the tire will deform and the bead area of the tire will be damaged. If damage occurs in the bead area, it is no longer possible to retread the tire in the tread area.

[0006] Furthermore, it is currently customary to use single-piece apexes made of a single rubber material with "average" or "low" rigidity. As a result of their triangular cross-sectional shape, single-piece apexes also result in a corresponding transition in rigidity in the bead area and the sidewall area, and in this respect, single-piece apexes are significantly inferior to multi-piece apexes. Thus, single-piece apexes are not optimal in terms of bead durability, but when a corresponding selection of rubber materials is made, they have proven to be advantageous in terms of rolling resistance.

[0007] The previously known multi-piece apexes, which are made of at least two apex parts, where it is customary for one apex part to be composed of a rubber material with higher rigidity and the other apex part to be composed of a rubber material with lower rigidity, are particularly advantageous for bead durability, and as a result, the risk of tire damage in the bead area is reduced. Thus, commercial vehicle tires have conventionally been considered for retreading.

[0008] Therefore, when designing and configuring the apex, the objective conflict between rolling resistance and bead durability has so far been resolved only insufficiently, which is directly related to retreadability.

Summary of the Invention

Problems to be Solved by the Invention

[0009] Therefore, an object of the present invention is to design a commercial vehicle tire of the type described at the beginning in a much more advantageous way than before with respect to the objective conflict between rolling resistance and bead durability.

Means for Solving the Problems

[0010] The above object is achieved according to the present invention, in which ○ the radially inner apex portion has a cross-sectional area having a surface area of 60% to 160% of the surface area of the cross-sectional area of the bead core, ○ the rubber material of the radially inner apex portion has a stress at 100% elongation that is 2.00 MPa to 30.00 MPa greater than the stress at 100% elongation of the rubber material of the radially outer apex portion determined according to DIN 53504 using test piece type S3, ○ the rubber material of the radially outer apex portion has a resilience at 70 °C that is 5.0 to 50.0 percentage points greater than the resilience at 70 °C of the rubber material of the radially outer apex portion determined according to ISO 4662 using a test piece having a thickness of 6.3 mm ± 0.5 mm in accordance with Annex A of ISO 4662.

[0011] According to the present invention, the radially inner apex portion has a cross-sectional area that is much smaller than that of conventional types heretofore, and the cross-sectional area of the radially inner apex portion is at least one-third, and even up to at least 50% smaller than that of conventional apexes heretofore. Although the radially inner apex portion is "small", as a result of the high rigidity of its rubber material (high stress at 100% elongation), a high level of bead stability (good bead durability) is maintained overall, and thus, the commercial vehicle tire is extremely suitable for retreading. In particular, the bead durability is significantly improved compared to current conventional one-piece apexes. Therefore, the radially outer apex portion, which is designed to have a larger cross-sectional area than heretofore, is composed of a rubber material having a much greater resilience at 70 °C than the resilience of the rubber material of the radially inner apex portion. Therefore, the rubber material of the radially outer apex portion is optimized from the viewpoint of the rolling resistance of the tire. In this case, the rolling resistance is significantly improved (low rolling resistance) especially compared to known commercial vehicle tires having two-piece apexes that were conventional heretofore. Therefore, the commercial vehicle tire according to the present invention is significantly improved with respect to the targeted trade-off between rolling resistance and bead stability.

[0012] According to a preferred embodiment, the surface area of the cross-sectional area of the radially inner apex portion is 70% to 140%, particularly 75% to 130%, preferably 80% to 120%, and particularly preferably at most 100% of the surface area of the cross-sectional area of the bead core. This is particularly advantageous with respect to the trade-off of the object to be solved.

[0013] According to another preferred embodiment, the stress at 100% elongation of the rubber material of the radially inner apex portion is 3.00 MPa to 25.00 MPa, preferably 4.00 MPa to 18.00 MPa, particularly preferably 4.50 MPa to 16.00 MPa, and most preferably 6.00 MPa to 12.00 MPa greater than the stress at 100% elongation of the rubber material of the radially outer apex portion. The difference shown has been found to be particularly advantageous for the bead durability of the tire.

[0014] In addition, when the stress at 100% elongation of the rubber material at the radially outer apex portion is from 0.50 MPa to 9.00 MPa, particularly from 0.75 MPa to 7.50 MPa, preferably from 1.00 MPa to 6.00 MPa, and particularly preferably from 2.50 MPa to 5.00 MPa, it is advantageous for bead durability.

[0015] Another preferred embodiment is characterized in that the resilience at 70 °C of the rubber material at the radially outer apex portion is 7.5 to 45.0 percentage points, preferably 9.0 to 40.0 percentage points, and particularly preferably 10.0 to 30.0 percentage points greater than the resilience at 70 °C of the rubber material at the radially inner apex portion. This contributes to a further reduction in the rolling resistance of the tire.

[0016] Furthermore, when the resilience at 70 °C of the rubber material at the radially inner apex portion is from 25% to 65%, particularly from 30% to 60%, and preferably at least 45%, it is advantageous for the rolling resistance of the tire.

[0017] According to another preferred embodiment, the carcass inlay has a single-layer design and terminates as a carcass turn-up having a height determined in the radial direction in each bead region, and the radially inner apex portion has, on the side facing the inner side of the tire in contact with the carcass inlay, a maximum height determined in the radial direction of 60% to 100%, particularly 70% to 90% of the height of the carcass turn-up, and the maximum height and the height are related to a line extending axially through a point corresponding to the rim transition point in the bead region of a commercial vehicle tire when viewed in the tire cross-section. This embodiment is also more advantageous for rolling resistance and bead durability.

[0018] According to an alternative further preferred embodiment, the carcass inlay has a multi-layer design, and each layer of the carcass inlay terminates as a carcass turn-up having a height determined in the radial direction in each bead region, and the radially inner apex portion has a maximum height determined in the radial direction of 60% to 100%, in particular 70% to 90%, of the maximum height of the carcass turn-up on the side facing the inner side of the tire in contact with the carcass inlay, and the maximum height and the height are related to a line extending axially through a point corresponding to the rim transition point in the bead region of the commercial vehicle tire when viewed in the tire cross-section. This embodiment is also further advantageous for rolling resistance and bead durability.

[0019] In the last two preferred embodiments described, the height of the carcass turn-up is in particular from 25.0 mm to 50.0 mm, preferably from 30.0 mm to 45.0 mm.

[0020] Preferably, the cross-sectional area of the radially inner apex portion is triangular, and the radially inner apex portion tapers at the end facing away from the bead core. This embodiment is further advantageous in terms of the desired trade-off between rolling resistance and bead durability.

[0021] Furthermore, in the last two embodiments described, it is advantageous if the radially outer apex portion extends between the carcass turn-up or each carcass turn-up and the radially inner apex portion when viewed in the tire cross-section.

[0022] Preferably, the commercial vehicle tire is provided for mounting on a 15° drop center rim standardized with a width code of 5.25 to 18.00 according to the E.T.R.T.O. standard.

[0023] The method of using the commercial vehicle tire according to the invention in a 15° drop center rim standardized with a width code of 5.25 to 18.00 according to the E.T.R.T.O. standard is particularly advantageous.

[0024] Here, further features, advantages, and details of the present invention will be described based on FIG. 1, which is a single drawing. FIG. 1 schematically shows a cross-section passing through one of the bead regions of a commercial vehicle tire having an embodiment of the present invention.

[0025] A commercial vehicle tire designed in accordance with the present invention is a tire for a multi-truck commercial vehicle, preferably a tire for a medium-weight truck (7.5 t < gross vehicle weight ≤ 18.0 t), a tire for a large truck (gross vehicle weight > 18.0 t), or a tire for a bus, particularly a commercial vehicle tire having a radial structure.

[0026] The heights shown below are measured in the radial direction (indicated by double-headed arrow R), and respectively, in the case of a commercial vehicle tire mounted on an appropriate rim and not inflated, relate to a line L extending in the axial direction (indicated by double-headed arrow A) passing through a point X corresponding to the rim transition point within each bead region of the commercial vehicle tire when viewed in the tire cross-section. The axial direction is to be understood as meaning a direction extending parallel to the rotation axis of the commercial vehicle tire. The radial direction corresponds to a direction extending perpendicular to the axial direction in the tire cross-section. The rim transition point is the intersection of the rim shoulder and the rim flange as is well known. The height is determined using a circumferential portion of the tire cut out from a vulcanized pneumatic vehicle tire fitted onto a rim. Alternatively, the height can be determined by computed tomography.

Brief Description of the Drawings

[0027]

Figure 1

Mode for Carrying Out the Invention

[0028] The commercial vehicle tire is provided for mounting on a 15° drop center rim (width codes 5.25 to 18.00) designed in accordance with the section of the latest version (as of July 19, 2022) of the European Tyre and Rim Technical Organization Standard Manual (the "E.T.R.T.O Standard") with a diameter designation of 17.5 inches, 19.5 inches, 20.5 inches, 22.5 inches, or 24.5 inches.

[0029] In FIG. 1, the components of the commercial vehicle tire are shown as a part of the airtight inner layer 1, a part of the sidewall 2, the flange profile 3, a part of the single-ply carcass inlay 4, the bead core 5, the two-piece apex 6 located on the bead core 5, the flipper strip 7, the steel cord bead reinforcement 8, the filler profile 9, and the filler profile 10. All of these components extend across the entire circumference of the tire and are thus components that circumferentially loop in the form of a ring.

[0030] The sidewall 2 overlaps with the flange profile 3 on the outer side of the tire. The carcass inlay 4 is composed of steel cords embedded in rubber and running substantially parallel to each other without intersecting each other. The carcass inlay 4 extends between two bead cores 5 in a well-known manner, and each bead core 5 is wound around from the inner side of the tire facing the inner layer 1 towards the outer side of the tire, and terminates as a carcass turn-up 4a at a height h1 of 25.0 mm to 50.0 mm, preferably 30.0 mm to 45.0 mm, adjacent to the apex 6 on the outer side of the tire. The flipper strip 7 is composed of a rubber-coated woven fabric, particularly a rubber-coated nylon fabric, and is arranged around the bead core 5 so as to separate the carcass inlay 4 from the bead core 5. The steel cord bead reinforcement 8 is composed of steel cords embedded in rubber and running substantially parallel to each other without intersecting each other, extends in contact with the side opposite to the bead core 5 of the carcass inlay 4, and terminates respectively on the inner side and the outer side of the tire in the region of the apex 6. The steel cord bead reinforcement terminates on the outer side of the tire before the termination of the carcass turn-up 4a. The filler profile 9 is arranged on the outer side of the bead core 5 and the apex 6, and in some parts, extends respectively between the steel cord bead reinforcement 8 and the flange profile 3, between the carcass turn-up 4a and the flange profile 3, and between the apex 6 and the flange profile 3 or the sidewall 2. The filler profile 10 extends between the two bead regions and is arranged in each bead region on the inner side of the bead core 5 and the apex 6. In each bead region, in some parts, it extends between the steel cord bead reinforcement 8 and the inner layer 1, and in some parts, it extends between the inner layer 1 and the carcass inlay 4.

[0031] The bead core 5 is formed by a core wire 5a that circumferentially winds around, has a high tensile strength, and is embedded in a rubber material. This wire is made of metal, particularly, and preferably has a circular cross-section. The bead core 5a is formed in a well-known manner by winding a single core wire 5a embedded in a rubber material or by winding a plurality of core wires 5a embedded in a rubber material. When viewed in the tire cross-section, the bead core 5 has a cross-sectional area having a surface area A5. In the case of the bead core 5 made of a single core wire 5a, the surface area A5 of the cross-sectional area of the bead core 5 is calculated from multiplying the surface area of the cross-sectional area of the core wire 5a by the maximum number of windings. Depending on the point in the cross-section, the number of windings can vary by one winding. The "maximum number of windings" is the number of windings at the point where the most windings are found. In the case of the bead core 5 made of a plurality of core wires 5a, the surface area A5 of the cross-sectional area of the bead core 5 is calculated from multiplying the number of core wires 5a by the surface area of the cross-sectional area of one core wire 5a. Therefore, when determining the surface area A5, the rubber material surrounding the core wire 5a or the plurality of core wires 5a is still not considered.

[0032] The two-part apex 6 preferably does not contact the bead core 5 and is composed of a radially outer apex portion 6a made of a rubber material and a radially inner apex portion 6b that contacts the bead core 5 and is also made of a rubber material. The rubber materials of the apex portions 6a and 6b are different in terms of the point of their stress at 100% elongation and the point of their resilience at 70°C, as will be described later.

[0033] In the illustrated exemplary embodiment, the radially inner apex portion 6b has a substantially triangular cross-sectional area when viewed in the tire cross-section, tapers along a portion of the carcass inlay 4 that extends along the inner side of the tire at the end facing away from the bead core 5, and reaches a maximum height h2 (height at the highest point) that is 60% to 100%, particularly 70% to 90% of the above-described height h1 of the carcass turn-up 4a. The cross-sectional area of the radially inner apex portion 6b is 60% to 160%, particularly 70% to 140%, preferably 75% to 130%, particularly preferably 80% to 120%, and most preferably up to 100% of the surface area A of the cross-sectional area of the bead core 5.6b has.

[0034] When viewed in the tire cross-section, the radially outer apex portion 6a extends between the carcass turn-up 4a and the radially inner apex portion 6b. Thus, together with the flipper strip 7, it separates the radially inner apex portion 6b from the carcass turn-up 4a and reaches a height h0 that is greater than the above-mentioned height h1 of the carcass turn-up 4a in the radial direction.

[0035] The above-mentioned stress at 100% elongation was determined in accordance with DIN 53504 (Testing of rubber and elastomers, determination of tensile rupture strength, tensile yield strength, tensile rupture elongation and stress values in a tensile test (2017 - 03 version), test piece type S3).

[0036] The rebound resilience at 70 °C was determined in accordance with ISO 4662 (Elastomers or thermoplastic elastomers, determination of the rebound resilience of vulcanizates (2017 - 06 version, pendulum method according to section 5)). Here, the thickness of the test piece was 6.3 mm ± 0.5 mm as described in Annex A (Use of non-standard test pieces).

[0037] The rebound resilience at 70 °C functions as an indicator of the rolling resistance of the tire, and a high rebound resilience at 70 °C means a low rolling resistance.

[0038] The rubber material of the radially outer apex portion 6a has a stress at 100% elongation of from 0.50 MPa to 9.00 MPa, particularly from 0.75 MPa to 7.50 MPa, preferably from 1.00 MPa to 6.00 MPa, and particularly preferably from 2.50 MPa to 5.00 MPa. The rubber material of the radially inner apex portion 6b has a stress at 100% elongation that is greater by from 2.00 MPa to 30.00 MPa, particularly from 3.00 MPa to 25.00 MPa, preferably from 4.00 MPa to 18.00 MPa, particularly preferably from 4.50 MPa to 16.00 MPa, and most preferably from 6.00 MPa to 12.00 MPa than the stress at 100% elongation of the rubber material of the radially outer apex portion 6a.

[0039] The rubber material of the radially outer vertex portion 6a has a resilience at 70 °C that is 5.0 to 50.0 percentage points, particularly 7.5 to 45.0 percentage points, preferably 9.0 to 40.0 percentage points, and particularly preferably 10.0 to 30.0 percentage points greater than the resilience at 70 °C of the rubber material of the radially inner vertex portion 6b. The rubber material of the radially inner vertex portion 6b has a resilience at 70 °C of 25% to 65%, particularly 30% to 60%, preferably at least 45%.

[0040] In the illustrated exemplary embodiment, three reinforcing strips 11, 12, 13 made of rubber and circumferentially surrounding are installed at the vertex 6 on the outside of the tire. The reinforcing strip 11 extends between the carcass turn-up 4a and the steel cord bead reinforcement 8. The reinforcing strip 12 extends over its entire portion and contacts the filler profile 9 and contacts the steel cord bead reinforcement 8, the carcass turn-up 4a, and the radially outer vertex portion 6a respectively at some portions. The reinforcing strip 13 covers the free end of the carcass turn-up 4a and extends in contact with the radially outer vertex portion 6a and the reinforcing strip 12 respectively at some portions.

[0041] Table 1 shows examples of rubber compounds A and B. The reported amounts of the components of rubber compounds A and B are provided in the conventional unit phr (parts per 100 parts of rubber) in the rubber technology. The reported amounts are based on 100 parts by mass of the base polymer respectively. Tires having corresponding vertices were manufactured from rubber compounds A and B as shown in Table 2 and compared as described later in Table 1.

[0042]

Table 1

[0043] A commercial vehicle tire for the steering axle having a tire size of 315 / 70R22.5 was manufactured. These tires differed only in terms of the apex design. The apexes had corresponding cross-sectional shapes and thus had cross-sectional areas with corresponding sizes. The differences between the apexes can be seen in Table 2. Table 2 further includes the results of tire tests, in which a rolling resistance test was carried out in accordance with ISO28580 (Method for Measuring the Rolling Resistance of Tires for Passenger Cars, Trucks, and Buses, Single Point Test and Correlation of Measurement Results, 2018 - 07 Edition), and a specially developed bead durability test (drum test) was carried out. The test result of the bead durability of the reference tire Ref.1 was limited to a value of 100. Values less than 100 indicate a decrease in bead durability.

[0044]

Table 2

[0045] From Table 2, it can be seen that the commercial vehicle tire according to the present invention has a much lower rolling resistance compared to the reference tire Ref.1 and remains good in terms of bead durability. Further, from Table 2, it can be seen that the commercial vehicle tire according to the present invention remains good in terms of rolling resistance and is much better in terms of bead durability compared to the reference tire Ref.2.

[0046] Furthermore, corresponding tests were carried out using the tires of the above-mentioned size for the drive axle and the tires of the above-mentioned size for the trailer axle. These tests also show corresponding improvements in the tires according to the present invention in terms of rolling resistance and bead durability.

[0047] The present invention is not limited to the exemplary embodiments described.

[0048] An additional reinforcing ply containing a reinforcing material and an additional reinforcing strip made of rubber can also be installed in the bead region of the tire. The carcass inlay 4 can also be designed in multiple layers, especially two or three layers. In the case of a multi-layer carcass inlay, the carcass turn-ups of the layers of the carcass inlay can also terminate at different heights. When viewed in the tire cross-section, the radially inner apex portion 6b can have a cross-sectional area different from that of the triangular cross-sectional area. The maximum height h2 of the radially inner apex portion 6b described above is from 60% to 100%, especially from 70% to 90% of the height of the maximum carcass turn-up. The flipper strip 7 and the reinforcing strips 11, 12, 13 of the steel cord bead reinforcement 8 are optional. The cross-sectional area of the bead core is especially hexagonal or circular. Alternatively, the cross-sectional area of the bead core has a shape derived from a hexagonal or circular shape. This type of derived shape is, for example, a cross-sectional area in the form of a hexagon having a cut-off corner region of a substantially parallelogram.

Explanation of Signs

[0049] 1 Inner layer 2 Sidewall 3 Flange profile 4 Carcass inlay 4a Carcass turn-up 5 Bead core 5a Core wire 6 Apex 6a Radially outer apex portion 6b Radially inner apex portion 7 Flipper strip 8 Steel cord bead reinforcement 9 Filler profile 10 Filler profile 11 Reinforcing ply 12 Reinforcing ply 13 Reinforcing ply A Double arrow (axial direction) A5, A 6b Surface area h0, h1 Height h2 Maximum height L Line R double arrow (radial direction) Point X

Claims

1. A commercial vehicle tire comprising a bead region each having a bead core (5), a two-piece apex (6) located radially outward on the bead core (5), and a flange profile (3), and further comprising a single-layer or multi-layer carcass inlay (4) wound around the bead core (5), wherein each apex (6) is composed of a radially outer apex portion (6a) and a radially inner apex portion (6b) in contact with the bead core (5), the radially outer apex portion (6a) and the radially inner apex portion (6b) are each composed of a rubber material, and the rubber material of the radially outer apex portion (6a) is different from the rubber material of the radially inner apex portion (6b). In a commercial vehicle tire, The radially inner vertex portion (6b) has a cross-sectional area having a surface area (A ５ of 60% to 160% of the surface area (A ６ｂ ) of the cross-sectional area of the bead core (5), the rubber material of the radially inner apex portion (6b) has a stress at 100% elongation that is 2.00 MPa to 30.00 MPa greater than the stress at 100% elongation of the rubber material of the radially outer apex portion (6a) determined according to DIN 53504 using a test piece type S3, the rubber material of the radially outer apex portion (6a) has a resilience at 70 °C that is 5.0 to 50.0 percentage points greater than the resilience at 70 °C of the rubber material of the radially outer apex portion (6b) determined according to ISO 4662 using a test piece having a thickness of 6.3 mm ± 0.5 mm in accordance with Annex A of ISO 4662. A commercial vehicle tire characterized by this.

2. The surface area (A ６ｂ ) of the cross-sectional area of the radially inner vertex portion (6b) is 70% to 140%, particularly 75% to 130%, preferably 80% to 120%, particularly preferably at most 100% of the surface area (A ５ ) of the cross-sectional area of the bead core (5). The commercial vehicle tire according to claim 1, characterized in that.

3. The commercial vehicle tire according to claim 1 or 2, characterized in that the stress at 100% elongation of the rubber material of the radially inner apex portion (6b) is 3.00 MPa to 25.00 MPa, preferably 4.00 MPa to 18.00 MPa, particularly preferably 4.50 MPa to 16.00 MPa, and most preferably 6.00 MPa to 12.00 MPa greater than the stress at 100% elongation of the rubber material of the radially outer apex portion (6a).

4. The commercial vehicle tire according to any one of claims 1 to 3, characterized in that the stress at 100% elongation of the rubber material of the radially outer apex portion (6a) is 0.50 MPa to 9.00 MPa, particularly 0.75 MPa to 7.50 MPa, preferably 1.00 MPa to 6.00 MPa, and particularly preferably 2.50 MPa to 5.00 MPa.

5. The resilience of the rubber material at 70 °C at the radially outer apex portion (6a) is 7.5 to 45.0 percentage points, preferably 9.0 to 40.0 percentage points, particularly preferably 10.0 to 30.0 percentage points greater than the resilience of the rubber material at 70 °C at the radially inner apex portion (6b). The commercial vehicle tire according to any one of claims 1 to 4, characterized by this.

6. The resilience of the rubber material at 70 °C at the radially inner apex portion (6b) is 25% to 65%, particularly 30% to 60%, preferably at least 45%. The commercial vehicle tire according to any one of claims 1 to 5, characterized by this.

7. The carcass inlay (4) has a single-layer design and, in each bead region, terminates as a carcass turn-up (4a) having a height (h １ ) determined in the radial direction (double arrow R), and the inner radial vertex portion (6b) faces the inner side of the tire in contact with the carcass inlay (4) and is 60% to 100%, in particular 70% to 90%, of the height (h １ ) of the carcass turn-up (4a) and has a maximum height (h ２ ) determined in the radial direction (double arrow R), and the maximum height (h ２ ) and the height (h １ ) are related to a line (L) extending in the axial direction (double arrow A) through a point (X) corresponding to the rim transition point in the bead region of the commercial vehicle tire when viewed in the tire cross-section, characterized in that the commercial vehicle tire according to any one of claims 1 to 6.

8. The carcass inlay (4) has a multi-layer design, and each layer of the carcass inlay (4) terminates as a carcass turn-up (4a) having a height (h １ ) determined in the radial direction (double arrow R) in each bead region, and the radially inner vertex portion (6b) faces the inner side of the tire in contact with the carcass inlay (4) and has a height (h １ ) of 60% to 100%, in particular 70% to 90% of the maximum height (h ２ ) determined in the radial direction (double arrow R), and the maximum height (h ２ ) and the height (h １ ) are related to a line (L) extending in the axial direction (double arrow A) through a point (X) corresponding to the rim transition point in the bead region of the commercial vehicle tire when viewed in the tire cross-section, characterized in that the commercial vehicle tire according to any one of claims 1 to 6.

9. said height (h) of said carcass turn-up (4a) １ ), being from 25.0 mm to 50.0 mm, preferably from 30.0 mm to 45.0 mm, characterized in that it is a commercial vehicle tire according to claim 7 or 8.

10. The cross-sectional area of the radially inner apex portion (6b) is triangular, and the radially inner apex portion (6b) tapers at the end facing away from the bead core (5). The commercial vehicle tire according to any one of claims 1 to 9, characterized by this.

11. The radially outer apex portion (6a) extends between the carcass turn-up (4a) or each carcass turn-up (4a) and the radially inner apex portion (6b) when viewed in the tire cross-section. The commercial vehicle tire according to any one of claims 7 to 10, characterized by this.

12. Provided to be mounted on a 15° drop center rim standardized with a width code of 5.25 to 18.00 according to the E.T.R.T.O. standard. The commercial vehicle tire according to any one of claims 1 to 11, characterized by this.

13. A method of using the commercial vehicle tire according to any one of claims 1 to 12 on a 15° drop center rim standardized with a width code of 5.25 to 18.00 according to the E.T.R.T.O. standard.

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