KR20240048729A - Heavy pneumatic tire with improved belt structure - Google Patents

Abstract

The present invention discloses a pneumatic tire for medium load with excellent durability, and for this purpose, the present invention stacks a plurality of belt layers, carcass plies, and liners in order on the lower part of the tread portion, and the upper belt among the adjacent belt layers A reinforcing cord is inserted between the layer and the lower belt layer, and the reinforcing cord is characterized in that it surrounds the upper belt layer and the lower belt layer. As a result, the belt layer of the tire is repeatedly stretched and stretched when the vehicle is driven. It effectively distributes the resulting stress and prevents belt separation even under high stress.

Description

Heavy pneumatic tire with improved belt structure}

The present invention relates to a pneumatic tire for medium loads with excellent durability. More specifically, it relates to a pneumatic tire for medium loads with excellent durability, and more specifically, to a tire that effectively distributes the stress generated by repeated bending and stretching movements during vehicle driving in the belt layer of the tire and prevents belt separation even under high stress. This relates to pneumatic tires for medium loads with excellent durability.

Tires are the only part that maintains direct contact with the road surface, bear the entire load of the car, and absorb all shock from the ground, which has a significant impact on improving ride comfort, making them an important component that requires high durability and safety.

These tires generate stress and frictional heat in the sidewall and tread due to continuous stretching and stretching during high-speed driving, and are especially concentrated in the shoulder area, which is the side of the tread, so they have poor adhesive properties. Separation accidents frequently occur at the end of this vulnerable shoulder belt.

Various technologies (e.g., Korean Patent No. 10-1818861, Korean Patent No. 10-1561304, Korean Patent No. 10-1723745, and Korean Patent No. 10-2187801, etc.) have been proposed to solve these problems. As can be seen in Figure 3, in the conventional tire 1000, the purpose is to prevent belt separation by inserting a 'ㄷ' shaped reinforcement material 10 to effectively disperse the stress and frictional heat generated at the end of the belt 500. However, in particular, the reinforcing material 10 inserted at the end of the third belt 530 was not effective in preventing separation from the other belts 520 and 540 due to stress and frictional heat.

In addition, as can be seen in FIG. 4, the reinforcing material 120 is inserted at the end of the belt layer 500 to cover the ends of the second belt 520 and the third belt 530 to reduce the concentrated stress applied to the ends. It has been proposed to prevent separation by dispersing, but this method still had difficulties in effectively blocking the shear stress between the second and third belts.

Korean Patent No. 10-1818861 (announced on February 21, 2018) Korean Patent No. 10-1561304 (announced on October 16, 2015) Korean Patent No. 10-1723745 (announced on April 5, 2017) Korean Patent No. 10-2187801 (announced on December 9, 2020)

Accordingly, the technical problem to be solved by the present invention is to provide a pneumatic tire for medium loads with excellent durability that effectively disperses the stress generated due to stretching movement in the belt layer and prevents belt separation even under high stress.

In order to solve the above-described technical problem, the present invention relates to a heavy-load tire in which a plurality of belt layers, carcass plies, and liners are sequentially laminated on the lower part of the tread portion, and the upper belt layer and the lower belt layer among the adjacent belt layers are provided. A reinforcing cord is inserted between the and the reinforcing cord, which surrounds the upper belt layer and the lower belt layer.

According to the above-described configuration of the present invention, a pneumatic tire for medium loads with excellent durability is provided.

The reinforcement cord is composed of two layers stacked up and down, the upper reinforcement cord covers the end of the upper belt layer, and the lower reinforcement cord is formed to cover the end of the lower belt layer.

According to the present invention, a lowermost belt layer is additionally provided inside the lower belt layer, and the lower reinforcement cord covers and wraps the ends of the lower belt layer and the lowermost belt layer in a two-stage shape.

Also, according to the present invention, an uppermost belt layer is added to the outside of the upper belt layer, and the upper reinforcement cord covers and wraps the ends of the upper belt layer and the uppermost belt layer in a two-stage shape.

According to a preferred embodiment of the present invention, the reinforcement cord covers and wraps the ends of the belt layers to have a length of at least 10 mm or more.

According to the present invention, a belt cushion material is inserted between the ends of the upper belt layer and the lower belt layer.

Also, according to the present invention, the reinforcement cord is made of nylon cord and is characterized by having a level of 19 to 21 EPI.

According to the present invention, a reinforcement cord composed of two layers stacked up and down is provided in the belt layer of the tire, the upper reinforcement cord covers and surrounds the end of the upper belt layer, and the lower reinforcement cord covers and protects the end of the lower belt layer. By doing so, the stress generated due to repeated bending and extension movements while driving the vehicle is effectively distributed, and belt separation can be prevented even under high stress.

In particular, one reinforcement cord covers and protects two belt layers simultaneously through a two-stage structure, which has the advantage of simplifying the structure and ensuring greater strength and support.

1 is an upper right half cross-sectional view of a tire showing a cross-section of a belt layer of a tire according to the present invention;
Figure 2 is an enlarged view of the main part of Figure 1,
Figures 3 and 4 are upper right half cross-sectional views of a tire showing the cross-section of the belt layer of a conventional tire.

Hereinafter, the present invention will be described in detail.

It should be noted that the technical terms used in the present invention are only used to describe specific embodiments and are not intended to limit the present invention, and the technical terms used in the present invention are not specifically defined in any other way in the present invention. Unless otherwise stated, it should be interpreted in the sense commonly understood by those skilled in the art to which the present invention pertains, and should not be interpreted in an excessively comprehensive sense or in an excessively reduced sense.

In addition, when the technical terms used in the present invention are incorrect technical terms that do not accurately express the idea of the present invention, they should be replaced with technical terms that can be correctly understood by a person skilled in the art, and the general terms used in the present invention are It should be interpreted according to what is defined in the dictionary or according to the context, and should not be interpreted in an excessively reduced sense.

Additionally, as used in the present invention, singular expressions include plural expressions unless the context clearly dictates otherwise. In the present invention, terms such as “consists of” or “comprises” should not be construed as necessarily including all of the various components or steps described in the invention, and some of the components or steps are included. It may not be possible, or it should be interpreted as including additional components or steps.

Hereinafter, preferred embodiments according to the present invention will be described in detail with reference to the attached drawings. However, identical or similar components will be assigned the same reference numbers regardless of the reference numerals, and duplicate descriptions thereof will be omitted.

In addition, in describing the present invention, if it is judged that a detailed description of related known technology may obscure the gist of the present invention, the detailed description will be omitted, and the attached drawings are intended to facilitate understanding of the spirit of the present invention. However, it should be noted that the spirit of the present invention should not be construed as limited by the attached drawings.

Figure 1 is an upper right half cross-sectional view of the tire 1000 showing the cross-section of the belt layer of the tire according to the present invention, and Figure 2 is an enlarged view of the main part of Figure 1. With reference to this, it is shown that the middle and lower parts with excellent durability according to the present invention. The intermediate pneumatic tire (1000) is a part in direct contact with the road surface and is formed of a strong rubber layer bonded to the outside of the carcass and breaker to increase static friction with the road surface under various driving conditions. It has a structure in which a plurality of belt layers 500, carcass plies 600, and liners 102 and 104 are stacked in order at the bottom of the tread portion 100 formed as an uneven portion, and the adjacent belt layers 500 ) A reinforcing cord 120 is inserted between the upper belt layer 530 and the lower belt layer 520, and the reinforcing cord 120 surrounds the upper belt layer 530 and the lower belt layer 520. It is formed of two stacked upper and lower reinforcement cords (120a, 120b).

Here, the tread portion 100, belt layer 500, carcass ply 600, and liner (102: inner liner, 104: back-up liner) are components of a typical tire, and their typical configuration may be left as is or modified. So it can be introduced and used.

Meanwhile, the belt layer 500 may include a plurality of belt layers. In particular, between the upper belt layer 530 (third belt) and the lower belt layer 520 (second belt layer), there are two layers. It has a structure in which upper and lower reinforcement cords (120a, 120b: 120 is used as a representative symbol) formed by stacking are inserted, and the ends (530a, 520a) extends in the direction of the sidewall 122 of the tire 1000, and separation may occur due to excessive stress and stress caused by repetitive stretching and stretching movements of the tire while driving, so durability may be reduced, and the extended end 530a , 520a), a portion of the belt cushion material 118 may be interposed between the ends of the upper belt layer 530 and the lower belt layer 520.

The reinforcing cord 120 is preferably introduced to buffer friction between steel cords, and non-metallic materials or polymer resins can be used. For example, nylon resin can be used as a reinforcing material, which increases or decreases the total weight of the tire. It has the advantage of not having a significant impact, being able to exert a reinforcing effect, and being able to withstand the load applied by the vehicle. In order to secure the above-mentioned rigidity, an EPI of 19 to 21 is preferable.

If the nylon is less than 19EPI, there is a possibility of poor adhesive interface separation due to a drop in cord tension and a decrease in adhesion at defective areas due to intensification of flow. Conversely, if it exceeds 21EPI, separation may occur due to an increase in cord rigidity. can occur.

The width or length (L1, L2, L3) surrounding the ends (530a, 520a) of the belt layer (530.520) is preferably 10 mm or more. If it is less than 10 mm, the reinforcing cord 120 may loosen due to a decrease in the adhesive area. This may develop into separation because it does not effectively prevent flow suppression in the belt layer (530.520).

Meanwhile, in addition to the upper and lower belt layers 530.520, one or more belts can be additionally formed by adding one more first belt layer 510 (lowest belt layer) to the inside of the lower belt layer 520. When forming three belt layers (530, 520, and 510), the lower belt layer 520 is formed to extend longer in the direction of the sidewall 122 than the first belt layer 510 located at the bottom, and then the lower reinforcement cord (120b) covers the end 520a of the lower belt layer 520 in a U-shape and extends to the tip of the end 510a of the first belt layer 510 and then again to the end of the first belt layer 510. (510a) is configured to cover a predetermined length (L3) or more, for example, 10 mm or more. In the case of forming a two-stage cover like this, it is very economical because the two belt layers (520, 510) can be covered and protected at the same time with one lower reinforcement cord (120b), especially the lower belt layer (520) and the lowest first belt layer. (510) Relative slide movement between the slides can be prevented through a two-stage cover, resulting in a stronger reinforcing effect. Also, for example, when the belt layer is formed into four layers (510, 520, 530, 540), the four belt ends are covered in a two-stage form using only two reinforcing cords (120a, 120b) in the same manner, that is, The upper reinforcement cord (120a) is an upper belt layer (530: third belt layer) and the uppermost belt layer, the fourth belt layer (540), and the lower reinforcement cord (120b) is a lower belt layer (520: second belt layer). By covering the first belt layer 510, which is the lowest belt layer, in a two-stage shape, the ends can be efficiently covered and reinforced.

The configuration that differentiates the present invention from the prior arts is that, in the prior arts of Patent Documents 1 to 4, the reinforcing member simply wraps only the end of the belt layer in a U-shape, that is, there are left and right U-shaped reinforcing members surrounding both left and right sides. Although they are different from each other, the present invention has the advantage of having a much greater effect of protecting the belt layer because the cogang cord is constructed across the side walls on both sides, and the ends of both sides wrapped in a U shape are integrally connected and tied together with tension. there is. In particular, one reinforcement cord simultaneously covers and protects two belt layers through a two-stage structure, simplifying the structure and ensuring greater strength and support.

Example

Attach a liner assembly to a tire forming drum, attach a steel body wave to both ends of the liner assembly, wrap a body ply on it, attach a bead and a hard apex/soft apex to both ends in order to turn it up, and turn the top of the turned-up steel body wave. After attaching the body wave cushion to the outer surface of the and apex, nylon body wave and insulating rubber are attached to their outer surfaces. After wrapping flange rubber from the bottom of the turned-up bead to the center of the insulating rubber, attach sidewall rubber to the outermost layer. Attach it, and attach the belt part on top of it by inserting reinforcement material into the upper part of the second belt layer and the lower part of the third belt layer. Then, attach the tread part on top of it and mold it into a tire. This is cured in the curing process to create a heavy load tire. Manufactured.

Comparative example

Attach a liner assembly to a tire forming drum, attach a steel body wave to both ends of the liner assembly, wrap a body ply on it, attach a bead and a hard apex/soft apex to both ends in order to turn it up, and turn the top of the turned-up steel body wave. After attaching the body wave cushion to the outer surface of the and apex, nylon body wave and insulating rubber are attached to their outer surfaces, and flange rubber is wrapped from the bottom of the turned-up bead to the center of the insulating rubber, and then attaching sidewall rubber to the outermost area. It was attached and molded into a tire, and this was vulcanized in a curing process to produce a heavy load tire.

Experiment example

The characteristic values of the tires according to the examples and comparative examples were structurally analyzed through simulation to obtain tensile energy density, cord tension, and temperature distribution data, which are shown in the table below.

Unit: psi
composition
Comparative example
Example
increase/decrease rate
belt cushion
41.76
40.62
97.3%
2nd belt
13.44
12.32
91.7%
3rd belt
14.75
12.60
85.4%

Unit: kgf
composition
Comparative example
Example
increase/decrease rate
2nd belt
34.78
34.43
99.0%
3rd belt
28.28
25.42
89.9%

Unit: ℃
composition
Comparative example
Example
increase/decrease rate
Belt end (belt cushion)
136.5
125.5
91.9%

Table 1 shows the strain energy density in pressure form, Table 2 shows the maximum cord tension, and Table 3 shows the maximum temperature. Referring to this, It was found that the overall tensile energy density, cord tension, and temperature distribution of the Example were reduced compared to the Comparative Example, and in particular, the strain energy of the belt cushion, which is a major factor in belt separation, and the maximum temperature of the belt end were reduced. You can check it. Therefore, it can be seen that the tire according to the example has an excellent effect compared to the comparative example by reducing stress concentration and shear stress through reinforcing the belt part, preventing separation defects, and improving the durability of the belt part.

Although preferred embodiments of the present invention have been described above with reference to the accompanying drawings, the embodiments described in this specification and the configuration shown in the drawings are only one of the most preferred embodiments of the present invention and do not represent the entire technical idea of the present invention. Since this is not the case, it should be understood that there may be various equivalents and modifications that can replace them at the time of filing this application. Therefore, the embodiments described above should be understood in all respects as illustrative and not restrictive, and the scope of the present invention is indicated by the claims described later rather than the detailed description, and the meaning and scope of the claims and their All changes or modified forms derived from the equivalent concept should be construed as falling within the scope of the present invention.

1000: Pneumatic tire
100: Tread part
102: Inner liner
104: Backup liner
118: Belt cushion material
120: Reinforcement code
120a: Upper reinforcement cord
120b: Lower reinforcement code
500: Belt layers
510: 1st belt layer (lowest belt layer)
510a: End of first belt layer
520: Lower belt layer (second belt layer)
520a: End of lower belt layer
530: Upper belt layer (3rd belt layer)
530a: End of upper belt layer
540: 4th belt layer (top belt layer)
600: Carcass Fly
L1, L2, L2: Length covering the end of the belt layer

Claims (7)

Apply multiple belt layers, carcass plies, and liners in order to the lower part of the tread section.
In the heavy load tire, a reinforcing cord is inserted between the upper belt layer and the lower belt layer among the adjacent belt layers, and the reinforcing cord has excellent durability, characterized in that it surrounds the upper belt layer and the lower belt layer. Pneumatic tires for medium loads. According to claim 1,
The reinforcement cord is composed of two layers laminated up and down, the upper reinforcement cord covers the end of the upper belt layer, and the lower reinforcement cord is formed to cover the end of the lower belt layer. Pneumatic tires for medium loads. According to claim 2,
A pneumatic tire for medium load with excellent durability, characterized in that a lowermost belt layer is added to the inside of the lower belt layer, and the lower reinforcement cord covers and wraps the ends of the lower belt layer and the lowermost belt layer in a two-stage shape. According to claim 3,
A pneumatic tire for medium load with excellent durability, characterized in that an uppermost belt layer is added to the outside of the upper belt layer, and the upper reinforcement cord covers and wraps the ends of the upper belt layer and the uppermost belt layer in a two-stage shape. The method according to any one of claims 1 to 4,
A pneumatic tire for medium load with excellent durability, characterized in that the reinforcement cord covers and wraps the ends of the belt layers to have a length of at least 10 mm or more. According to claim 5,
A pneumatic tire for medium load with excellent durability, characterized in that a belt cushion material is inserted between the ends of the upper belt layer and the lower belt layer. The method according to any one of claims 1 to 4,
The reinforcement cord is made of nylon cord, and is a pneumatic tire for medium load, characterized in that it has a level of 19 to 21 EPI.