Tire having a profiled structure of the bead portion with enhanced transverse rigidity

Abstract

According to an embodiment of the present application, in order to improve lateral rigidity, a tire including a tread portion, a sidewall portion, and a bead portion (10) is provided, wherein the tire is a tire having a bead contour structure in which the X coordinate of the outermost edge point (P) of the bead portion (10) contacting a rim (rim) is 8.8 to 9.7 mm and the Y coordinate is 19.2 to 21.7 mm at the coordinate origin (O) of the ETRTO (European Tire and Rim Technical Organization) standard reference point.

Description

Technical Field

[0001] This invention relates to a vehicle tire, and more specifically, to a tire having a bead profile structure that improves lateral rigidity. Background Technology

[0002] A typical tire is designed to consist of a cap lie, a belt, a carcass, a bead core made of bead wire, a bead filler, and a bead bundle, which together form the tread, the sidewall, and the bead.

[0003] In the above structure, the bead core, composed of multiple central bead wires, and the bead portion, consisting of hard rubber, synthetic tensile rubber, bead filler, and bead bundle covering the bead core, are the parts that contact the rim. They serve to wrap the ends of the tire cords and mount the tire onto the rim. Furthermore, this bead portion also supports the load applied to the tire and transmits torque during braking.

[0004] The bead portion in the above structure is divided into the RPB type bead portion with a rim protect bar (RPB) and the RCL type bead portion with a rim check line (RCL). For example... Figure 1 As shown, Figure 1 (a) is a cross-sectional view of the RPB type bead portion in the prior art. Figure 1 (b) is a cross-sectional view of the bead portion of the RCL type tire.

[0005] Figure 1 The RPB type bead portion of (a) is typically suitable for low series specifications, while Figure 1 (b) The RCL type bead portion is typically applicable to High Series specifications.

[0006] If the bead portion of the above-mentioned structure is designed to improve lateral stiffness (KL (kgf / mm)), handling performance can be improved. Therefore, to improve handling performance, tires with a bead portion profile structure that improves lateral stiffness are needed.

[0007] Patent Document 1: Korean Patent Publication No. 2020-0121404 (published on October 26, 2020) Summary of the Invention

[0008] The problem the invention aims to solve

[0009] Therefore, the present invention aims to solve the problems in the prior art described above. The technical problem to be solved is to improve lateral stiffness by applying a new bead profile structure, thereby providing a tire with a lateral stiffness-enhanced bead profile structure that improves handling performance.

[0010] means for solving problems

[0011] To achieve the above objectives, one embodiment of the present invention includes a tread portion, a sidewall portion, and a bead portion 10, wherein the bead portion 10 is configured such that its outermost edge point P, at the portion contacting the rim of the wheel hub, has an X-coordinate range of 8.8 to 9.7 mm and a Y-coordinate range of 19.2 to 21.7 mm based on the ETRTO (European Tyre and Rim Technology Organization) commercial rim standard reference point coordinate origin O, to provide a tire with a laterally reinforced bead portion profile structure. Preferably, the X-coordinate of the outermost edge point P of the bead portion can be 8.8 ± 0.1 mm.

[0012] When inflated, the tire's sidewall width is located on the outermost side, thus eliminating the need for a rim guard, and it has a bead profile structure for improving lateral rigidity.

[0013] The bead portion 10 includes a lower bead portion 11 and an upper bead portion 13 relative to the outermost edge point P of the bead portion, wherein the outer radius of curvature R1 of the lower bead portion 11 is in the range of 30 to 100 mm, while the outer radius of curvature R2 of the upper bead portion 13 can be in the range of 1000 mm to infinity (i.e., a straight line).

[0014] The outermost point P of the bead portion is a curved surface in the direction of the inner side of the tire, and its radius of curvature R3 is in the range of 0.5 to 2 mm, preferably 1 mm.

[0015] The effects of the invention

[0016] According to one embodiment of the present invention described above, the tire can significantly improve handling performance through a bead profile structure that enhances lateral rigidity. Attached Figure Description

[0017] Figure 1 This is a cross-sectional view of the RPB type bead portion a and the RCL type bead portion b in the prior art.

[0018] Figure 2 This is a schematic diagram representing an ETRTO standard commercial wheel rim.

[0019] Figure 3 This is a schematic diagram illustrating the bead profile structure of a tire 1 for improving lateral rigidity according to an embodiment of the present invention.

[0020] Figure 4 This is a schematic diagram showing the contact pressure distribution between the tire bead and the rim of a tire with X and Y coordinates (12.5mm, 23.23mm) at the outermost point P of the bead portion under 140% of the maximum ETRTO load.

[0021] Figure 5 This is a schematic diagram showing the shape changes of tire a without the bead profile structure of the present invention and tire b with the profile structure. Detailed Implementation

[0022] According to a preferred embodiment of the present invention, the tire includes a tread portion, a sidewall portion, and a bead portion 10, wherein the outermost edge point P of the bead portion 10 contacts the rim, and the X coordinate range of the origin O of its ETRTO (European Tire and Rim Technology Organization) standard commercial rim reference point is 8.8 to 9.7 mm, and the Y coordinate range is 19.2 to 21.7 mm.

[0023] In the following description of the invention, detailed descriptions of relevant known functions or structures will be omitted if such descriptions may unnecessarily obscure the essential points of the invention.

[0024] According to the concept of the present invention, embodiments can be modified in various ways and have multiple forms; therefore, specific embodiments are shown in the drawings and described in detail in this specification or application. However, this is not intended to limit the embodiments of the present invention to the specific disclosed forms, and the present invention should be understood to include all modifications, equivalents, or substitutions within the spirit and scope of the present invention.

[0025] When a component is said to be "connected to" or "accessed" by another component, it should be understood that the component can directly connect to or access the other component, but there may also be other intermediate components. Conversely, when a component is said to be "directly connected to" or "directly accessed" by another component, it should be understood that there are no other intermediate components. Similarly, other expressions describing the relationship between components, such as "between" and "directly between" or "adjacent" and "directly adjacent," should also be interpreted accordingly.

[0026] The terminology used in this specification is for illustrative purposes only and is not intended to limit the invention. Unless explicitly indicated in the context otherwise, the singular form shall include the plural form. In this specification, the terms "comprising" or "having," etc., mean the presence of the stated features, quantities, steps, actions, components, parts, or combinations thereof, and do not preclude the possibility of the presence or addition of one or more other features, quantities, steps, actions, components, parts, or combinations thereof.

[0027] The embodiments of the present invention will now be described in more detail with reference to the accompanying drawings.

[0028] Figure 2 This is a schematic diagram showing the ETRTO standard commercial wheel rim. Figure 3 This is a schematic diagram illustrating the bead profile structure of a tire 1 for improving lateral rigidity according to an embodiment of the present invention.

[0029] like Figure 2 As shown, according to ETRO commercial standards, the radius of curvature R11 of the rim flange in the lateral (X-axis direction) contacting the tire is 9.7 mm. Therefore, the highest point in the tire height direction (Y-axis direction) is formed at X-9.7 mm. If the radius of curvature of the lateral rim flange exceeds 9.7 mm, it cannot contact the rim, thus reducing the effect of rigidity enhancement.

[0030] Therefore, as Figure 3 As shown, the tire 1 includes a tread portion (not shown), a sidewall portion (not shown), and a bead portion 10. The outermost edge point P of the bead portion 10 contacts the rim. The X-coordinate of its ETRTO (European Tyre and Rim Technology Organization) standard commercial rim reference point O ranges from 8.8 to 9.7 mm, preferably 8.8 mm (or 8.8 ± 0.1 mm), and the Y-coordinate ranges from 19.2 to 21.7 mm. Here, the outermost edge point P of the bead portion is the outermost position where the tire 1 contacts the rim.

[0031] Furthermore, when the tire 1 is inflated, its sidewall width (a standard that determines the outermost dimension of the central part of the tire, as specified in ETRTO) can be located on the outermost side, thus eliminating the need for a rim guard.

[0032] Furthermore, the bead portion 10 includes a lower bead portion 11 and an upper bead portion 13 relative to the outermost edge point P of the bead portion, wherein the outer radius of curvature R1 of the lower bead portion 11 ranges from 30 to 100 mm, while the outer radius of curvature R2 of the upper bead portion 13 ranges from 1000 mm to infinity (i.e., a straight line).

[0033] The outermost point P of the bead portion has a radius of curvature R3 of 0.5 mm to 2 mm, preferably 1 mm, in the direction of the inner side of the tire, and is processed into a round surface.

[0034] Figure 4 This is a schematic diagram showing the contact pressure distribution between the tire bead and the rim for a tire with X and Y coordinates (12.5 mm, 23.23 mm) at the outermost point P of the bead portion under 140% of the maximum ETRTO load.

[0035] like Figure 4 As shown, when a tire with an X and Y coordinate of (12.5 mm, 23.23 mm) at the outermost point P of the bead portion is subjected to 140% of the maximum ETRTO load, if the X coordinate is based on 8.8 mm, the tire will not make contact with the rim when the X coordinate of the outermost point P exceeds 8.8 mm. That is, if the X and Y coordinates of the outermost point P of the bead portion are designed to be (8.85 mm, 21.25 mm), then when a 140% maximum ETRTO load is applied, lateral displacement can be minimized by pre-guiding the contact between the tire and the rim. This minimization of lateral displacement achieved through pre-contact helps improve lateral stiffness (kgf / mm).

[0036] Specifically, the X and Y coordinates of the outermost point P of the bead portion, used to improve lateral stiffness, are (8.8mm, 20.6mm) for the RPB bead portion 20 and (8.8mm, 21.2mm) for the RCL bead portion 30. The X coordinate can be designed within the range of 8.8 to 9.7mm, depending on the tire specification. The Y coordinate value corresponding to the change in X coordinate can be designed within the range of 19.2 to 21.7mm.

[0037] The X and Y coordinates of the outermost point P of the bead are designed within the range where the tire rim flange will not wear. These design values ​​are based on actual tire field test experience.

[0038] As described above, the outer radius of curvature R1 of the lower bead portion 11 is based on 30 mm and can be extended to 100 mm to provide additional performance improvement. The outer radius of curvature R2 of the upper bead portion 13 is based on 1000 mm, but can be adjusted to a straight line to achieve further performance improvement.

[0039] The outermost point P of the bead portion is a curved surface in the direction of the inner side of the tire, with a radius of curvature R3 of 0.5 mm to 2 mm, preferably 1 mm, and is processed as a round surface.

[0040] Furthermore, the optimized coordinate values ​​for improving lateral stiffness have been confirmed using data from finite element analysis (FE analysis) and actual tire evaluation results.

[0041] Table 1 is a table showing the lateral stiffness improvement rate corresponding to the coordinates of the outermost point P of the RPB bead portion 20 and the RCL bead portion 30 using the bead portion contour structure of the present invention.

[0042] Table 1

[0043]

[0044] As shown in Table 1, when the bead contour structure of the present invention is applied to tires of both RCL and RPB bead types, the analysis results show that the lateral rigidity KL is increased by approximately 3%. If the X-coordinate of the outermost point P of the bead contour structure in the tire of the present invention exceeds 8.8 mm, the pre-contact effect between the rim and the bead almost disappears, and only the bending rigidity effect due to the increase in rubber volume is observed. Therefore, it can be confirmed that the X-coordinate of the outermost point P, 8.8 mm, is the optimal X-coordinate for improving lateral rigidity.

[0045] Furthermore, for tires with RPB beads, although the X-coordinate of the outermost point P is 8.8 mm, different Y-coordinate values ​​will lead to variations. This is because different tire specifications have different low sidewall designs, such as LSH and LSR. Therefore, by applying the Y-coordinate within the range of 19.2 to 21.7 mm, a lateral stiffness-enhancing bead profile structure that meets specifications can be designed.

[0046] Figure 5 The diagram illustrates the shape changes of tire a without the bead contour structure of the present invention and tire b with the structure.

[0047] like Figure 5 As shown, it can be confirmed that the lateral displacement of tire b with the bead profile structure of the present invention is reduced, and the lateral stiffness can be improved by about 3% by guiding the rim to pre-contact under vertical load.

[0048] The bead contour structure of the present invention described above can be applied to 04-Ply tires of the 50 series and above.

[0049] The bead contour structure of the present invention described above can be applied to tires of various vehicles such as passenger car PCR tires, racing cars, and electric vehicles.

[0050] While the technical concept of the present invention described above has been specifically illustrated in preferred embodiments, these embodiments are merely illustrative of the technical content of the invention and are not intended to limit its scope. Furthermore, those skilled in the art will understand that various different embodiments are possible within the scope of the technical concept of the present invention. Therefore, the true technical scope of the present invention should be determined by the technical concept of the appended claims.

[0051] Explanation of reference numerals in the attached figures

[0052] 1: Tires

[0053] 10: Bead area

[0054] 20: RPB bead section

[0055] 30: RCL bead section

[0056] P: The outermost point of the bead portion that contacts the rim.

[0057] X: X-coordinate of the outermost point (P)

[0058] Y: Y-coordinate of the outermost point (P)

[0059] 11: Lower bead section

[0060] R1: Radius of curvature of the outer side of the lower bead portion

[0061] R11: Rim flange curvature radius

[0062] 13: Upper bead section

[0063] R2: Radius of curvature of the outer side of the upper bead portion

[0064] O: Origin of coordinate system (reference point according to ETRTO commercial wheel rim standard)

[0065] RD: Rim Diameter

Claims

1. A tire with a bead profile structure that enhances lateral rigidity, characterized in that, The tire includes a tread portion, a sidewall portion, and a bead portion (10), wherein the outermost point (P) of the bead portion has an X-coordinate relative to the ETRTO (European Tire and Rim Technology Organization) commercial rim standard reference point (O) coordinate origin (O) of the rim in the range of 8.8 to 9.7 mm, and a Y-coordinate in the range of 19.2 to 21.7 mm. The outermost point (P) of the bead portion is the outermost position where the tire contacts the rim. The bead portion (10) includes a lower bead portion (11) and an upper bead portion (13) with the outermost edge point (P) of the bead portion as a reference. The outer radius of curvature (R1) of the lower bead portion (11) ranges from 30 to 100 mm, and the outer radius of curvature (R2) of the upper bead portion (13) ranges from 1000 mm to infinity (straight line).

2. The tire with an enhanced lateral rigidity bead profile structure according to claim 1, characterized in that, When inflated, the tire's sidewall width is at its outermost position, thus eliminating the need for rim protection devices.

3. The tire with an enhanced lateral rigidity bead profile structure according to claim 1, characterized in that, The outermost point (P) of the bead portion has a curved surface in the direction of the inner side of the tire with a radius of curvature (R3) of 0.5 to 2 mm, and the surface is treated.

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