KR20160017367A

KR20160017367A - Tire groove structure improving groove crack

Info

Publication number: KR20160017367A
Application number: KR1020140100558A
Authority: KR
Inventors: 배성렬; 최명락
Original assignee: 한국타이어 주식회사
Priority date: 2014-08-05
Filing date: 2014-08-05
Publication date: 2016-02-16

Abstract

According to the present invention, in the tire groove structure, the depth of the outermost groove is maintained at 85% or less of the main groove depth so as to minimize the deformation rate and the function of the pattern, A tire capable of minimizing the groove crack by keeping the safety distance of the second belt end and the groove inflection point at 35% or more of the tread width in order to minimize the deformation of the groove inflection point from the stress generated at the end of the belt Groove structure.

Description

[0001] TIRE GROOVE STRUCTURE IMPROVING GROOVE CRACK [0002]

More particularly, the present invention relates to a tire groove structure in which a depth of an outermost groove is maintained at 85% or less with respect to a main groove, The present invention relates to a tire groove structure capable of minimizing a cracking phenomenon occurring at a groove inflection point by maintaining a safety distance of an inflection point at 35% or more of a tread width (TW).

Generally, the pneumatic tire includes an inner liner constituting an inner circumference of a tire, a tread portion having a belt layer contacting the road surface, a carcass serving as a skeleton of a tire supporting a load by a tire inner cord layer, A side wall portion for protecting the carcass and performing a bending motion, and a bead portion for wrapping the end portion of the cord and attaching the tire to the rim.

On the other hand, grooves are provided in the tread part of most automobile tires such as PCR and TBR to ensure various performance such as drainage performance, braking performance and heat generation. However, depending on the conditions of use of the vehicle and the pavement of the road, a quality problem such as a groove crack is caused by an excessive lateral force, a step on the road, or a stone bite phenomenon in which stones or other protrusions are stuck in a vehicle running .

1 is a cross-sectional view of a general groove. In order to improve the groove crack, there is a lot of studies about the design value of the round value and the groove width of the bottom surface of the groove. Conventional techniques for preventing groove cracks in heavy duty tires can be summarized as ① groove side angle adjustment (A1) and ② groove back side radius adjustment (R1).

That is, the conventional groove prevents the groove crack by adjusting the groove side angle A1 and the back circle radius R1 as shown in the left drawing of FIG. However, as shown in the right side of FIG. 2, such a conventional groove structure has a problem that excessive stress acts on the edge of the groove backside during load operation, thereby preventing stress concentration and causing groove cracks. 3 is a photograph actually taken of a section of a tire in which such a groove crack occurred.

SUMMARY OF THE INVENTION It is an object of the present invention to provide a method of manufacturing a tire having a tread width TW, And to provide a tire groove structure capable of preventing a groove crack by establishing a standard of an outermost groove.

According to one aspect of the present invention, there is provided a tire groove structure in which a depth of an outermost groove is defined as a depth of a groove, And 85% or less, preferably 85% to 75%, of the groove depth.

In order to minimize the deformation of the groove inflection point from the stress generated at the end portion of the second belt, the safety distance between the second belt end and the groove inflection point is set to be greater than the tread width To 35% or more, and preferably 35 to 45%.

According to another aspect of the present invention to achieve the above object, the present invention provides a tread having a depth of the outermost groove of 85% or less with respect to the main groove, a safety distance between the end of the second belt and the groove inflection point of 35% The present invention relates to a tire groove structure for holding a tire.

The tire groove structure according to the present invention having the above-described characteristics is characterized in that the distance between the second belt and the outermost groove bent portion is standardized against the tread width and the standard of the outermost groove is established, thereby preventing the groove crack Thus, it is possible to prevent large-scale accidents in advance and to minimize quality issues from consumers.

1 is a cross-sectional view of a general groove.
2 is a diagram schematically showing the principle of generating a groove crack in a conventional groove structure.
3 is a photograph of a crack occurring in a conventional tire groove.
4 is a view showing the structure of each part related to the standardization of the tire groove structure according to the present invention.
5 is a graph simulating the deformation rate in a circumferential direction when a load acts on a tire groove.
6 is a graph simulating the deformation rate in the width direction when a load is applied to the tire groove.
FIG. 7 is a result of verifying the effect of improving the groove crack in the tire groove structure according to the present invention through MSDB analysis.

Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the accompanying drawings. In the following description of the present invention, a detailed description of known general functions or configurations will be omitted.

The present invention relates to a tire groove structure in which the distance between the second belt and the outermost groove bent portion is standardized with respect to the tread width and the groove crack is improved by establishing the standard of the outermost groove.

4 is a view showing the structure of each part related to the standardization of the tire groove structure according to the present invention. 4, the tire groove structure according to the present invention is designed such that the depth C of the outermost groove is set to 85% or less of the main groove depth so as to minimize the deformation rate and maintain the function of the pattern as much as possible, It is recommended to keep it at 85 ~ 75%.

When the depth C of the outermost groove reaches 85% or less of the depth of the main groove, the backside in the groove becomes large, and the possibility of crack initiation becomes small. That is, when the back surface R is small, the stress concentration phenomenon becomes large on the back surface of the groove, and when the load is applied, the possibility of cracks increases.

In order to minimize the deformation of the groove inflection point from the stress generated at the end portion of the second belt, the tire groove structure according to the present invention is characterized in that the safety distance A between the second belt end and the groove inflection point is 35% Preferably, it is maintained at 35 to 45%.

Accordingly, when A is 35% or more of the width of the tread, the distance between the outermost groove and the second belt is secured to a certain distance or more, so that the deformation amount of the outermost groove is reduced when the load is applied, thereby improving the groove crack. If A is less than 35% of the tread width, when the load is applied, the distance between the outermost groove and the second belt is shortened so that the shear force inside the outermost groove increases (lateral force and torsion) .

The tire groove structure according to the present invention may also maintain the depth of the outermost groove at 85% or less of the main groove and at the same time maintain the safety distance between the second belt end and the groove inflection point at 35% or more of the tread width.

FIG. 5 is a graph simulating the deformation rate in the circumferential direction when a load acts on the tire groove, and FIG. 6 is a diagram simulating the deformation rate in the width direction.

Finite element analysis (FEA: MSDB) was carried out to understand the effects of grooving crack improvement before and after the product. The results are shown in FIG. 7 and Table 1 below.

Referring to FIG. 7 and Table 1 below, it is judged that there are two effects on the FEA before and after the improvement of the groove crack. First, since the groove crack occurs mainly in the outermost groove, the strain energy density (SED) of the outermost groove is analyzed It can be seen that the strain energy density is reduced by 50% compared to the improvement after the improvement (R26), so that it is unlikely to occur in the groove crack, that is, the improvement effect is large. The width change of the outermost groove is improved by the finite element analysis It can be seen that the groove width improvement is effective when the overall groove width is smaller than before the improvement (in the air pressure state: normal state → air pressure → load).

[Table 1]

While the present invention has been particularly shown and described with reference to exemplary embodiments thereof, it is to be understood that the invention is not limited to the disclosed exemplary embodiments. This will be obvious.

A: Distance between the end of the second belt and the grooved portion
B: Distance between the tread width end point and the outermost back surface R
C: outermost groove depth

Claims

In the tire groove structure,
Wherein the groove structure maintains the depth of the outermost groove at 85% or less of the main groove depth so as to minimize the deformation rate and maintain the function of the pattern as much as possible.

In the tire groove structure,
In order to minimize the deformation of the groove inflection point from the stress generated at the end of the second belt, the groove structure maintains the safety distance of the second belt end and the groove inflection point at 35% or more of the TW (Tread Width) A tire groove structure.

In the tire groove structure,
Wherein the groove structure maintains the depth of the outermost groove at 85% or less of the main groove and maintains the safety distance between the second belt end and the groove inflection point at 35% or more of the TW (Tread Width) .

The tire groove structure according to claim 1, wherein the groove structure maintains the depth of the outermost groove at 85 to 75% of the main groove.

3. The tire groove structure according to claim 2, wherein the groove structure maintains the safety distance between the second belt end and the groove inflection point at 35 to 45% of the TW (Tread Width).