EP-4737135-A1 - HEAVY-DUTY TIRE

Abstract

A heavy-duty tire with enhanced pattern stiffness and suppressed irregular wear is disclosed. The tire comprises a block portion including a center rib and side ribs, and a main groove extending circumferentially between them. A hidden groove and a reinforcing rib are formed alternately and spaced apart within the main groove. The hidden groove and the reinforcing rib enhance pattern stiffness by allowing the center and side ribs to contact laterally. The reinforcing rib disperses forces generated during driving and braking, effectively suppressing irregular wear. Furthermore, the reinforcing rib is configured to wear while maintaining a step difference of 2 mm to 3 mm with the adjacent block portion, thereby significantly improving drainage performance from an initial stage of wear.

Inventors

• JANG, TAE YOUNG
• Chun, Eun Chang

Assignees

• HANKOOK TIRE & TECHNOLOGY CO., LTD

Dates

Publication Date

20260506

Application Date

20240627

Claims (10)

1. A heavy-duty tire, comprising: a block portion comprising a center rib and side ribs provided on both sides of the center rib; a main groove provided to partition a space between the center rib and the side ribs and extending in a circumferential direction of the tire; a hidden groove formed in the main groove; and a reinforcing rib formed in the main groove, wherein the hidden groove and the reinforcing rib are formed alternately in the main groove, being spaced apart from each other.
2. The heavy-duty tire of claim 1, wherein the hidden groove comprises: a hidden block forming a body; a hidden kerf extending in a depth direction of the hidden block; and a hidden channel formed at a lower part of the hidden kerf.
3. The heavy-duty tire of claim 2, wherein the hidden block is formed to have a width that is 100% to 200% of a width of the reinforcing rib.
4. The heavy-duty tire of claim 3, wherein the hidden channel is formed such that its cross-sectional area in a width direction is 80% or less of a cross-sectional area in the width direction of the main groove.
5. The heavy-duty tire of claim 1, wherein the reinforcing rib is formed to have a width of 70% or more of a width of the main groove.
6. The heavy-duty tire of claim 5, wherein the reinforcing rib is formed to have a height of 80% to 90% of a depth of the main groove.
7. The heavy-duty tire of claim 6, wherein the reinforcing rib is formed such that it wears while maintaining a step difference of 2 mm to 3 mm relative to the adjacent block portion.
8. The heavy-duty tire of claim 1, wherein the reinforcing rib comprises: a reinforcing body forming a body; a reinforcing recess formed on an upper surface of the reinforcing body; and a reinforcing kerf formed on a surface of the reinforcing body facing the block portion.
9. The heavy-duty tire of claim 8, wherein both sides of the reinforcing body contact the center rib and the side ribs, respectively.
10. The heavy-duty tire of claim 8, wherein the reinforcing recesses are formed at equal intervals on the top surface of the reinforcing body and have a depth of 0.5 mm or less.

Description

BACKGROUND Field The present disclosure relates to a heavy-duty tire in which pattern rigidity is improved and irregular wear is suppressed, and more particularly, to a heavy-duty tire capable of enhancing drainage performance while simultaneously improving pattern rigidity and suppressing irregular wear. Description of the Related Art Generally, to secure various performances such as drainage performance, braking performance, and heat generation in pneumatic tires for heavy-duty use, a tread of a pneumatic tire for a vehicle is provided with a plurality of grooves, and a plurality of blocks are separated and formed by the grooves. Among the important performances of a tire, the enhancement of the function of water absorption and drainage on a wet road surface is gradually being emphasized, and a technology for maintaining or increasing the durability of the tire while enhancing the function of water absorption and drainage is required. To this end, a conventional technology has been developed to form a separate hidden channel in a groove of a tire. Such a hidden channel has the effect of improving mileage, driving performance, and rolling resistance, and also the effect of improving pattern stiffness. However, this technology had a problem in that the drainage performance decreased due to the reduction of the groove area at the initial stage of wear. And, the hidden channel is exposed when the wear rate exceeds 70%, thereby improving the drainage performance, but conversely, the pattern stiffness decreases, leading to problems such as irregular wear and decreased driving performance. Therefore, a technology is required that enhances drainage performance and prevents pattern stiffness from decreasing even after the middle stage of wear. SUMMARY The present invention is directed to solving the above-mentioned problems in the related art, and an object of the present invention is to provide a heavy-duty tire that enhances drainage while simultaneously improving pattern stiffness and suppressing irregular wear. The above object is achieved by a heavy-duty tire comprising: A block portion comprising a center rib and side ribs provided on both sides of the center rib; A main groove provided to partition the space between the center rib and the side ribs and extending in a circumferential direction of the tire; A hidden groove formed in the main groove; and A reinforcing rib formed in the main groove, wherein the hidden groove and the reinforcing rib are formed alternately in the main groove, being spaced apart from each other. According to an embodiment, the center rib and the side ribs are brought into lateral contact via the hidden groove and the reinforcing rib, thereby enhancing the pattern stiffness, which improves driving performance and rolling resistance. Furthermore, the reinforcing rib disperses and absorbs the force generated in the center rib and the side ribs during driving and braking, reducing the irregular wear of the center rib and the side ribs. Moreover, the reinforcing rib wears while maintaining a step difference of 2 mm to 3 mm with the adjacent center rib and side ribs, thereby improving drainage performance from an initial stage of wear compared to when only the hidden groove is present. BRIEF DESCRIPTION OF DRAWINGS Figure 1 is an exemplary view of a heavy-duty tire with enhanced pattern stiffness and suppressed irregular wear according to an embodiment of the present invention.Figure 2 is a plan view of the main groove, the hidden groove, and the reinforcing rib according to an embodiment of the present invention.Figure 3 is a cross-sectional view taken along line A-A of the main groove in Figure 2.Figure 4 is a cross-sectional view taken along line B-B of the hidden groove in Figure 2.Figure 5 is a longitudinal cross-sectional view of the reinforcing rib according to an embodiment of the present invention.Figure 6 is a cross-sectional view taken along line C-C of the reinforcing rib in Figure 2.Figure 7 is an exemplary view of the reinforcing rib according to an embodiment of the present invention. DETAILED DESCRIPTION In the following description of the present invention, a detailed description of related known functions or configurations may be omitted if it is deemed to unnecessarily obscure the gist of the present invention. Since embodiments according to the concept of the present invention are subject to various changes and may take various forms, specific embodiments will be illustrated in the drawings and described in detail in the present specification or application. However, this is not intended to limit the embodiments according to the concept of the present invention to the specific disclosed forms, and the present invention should be understood to include all modifications, equivalents, and substitutes included within the spirit and technical scope of the present invention. When a component is referred to as being "connected" or "coupled" to another component, it is to be