KR101723753B1 - Dual Apex for Pneumatic Tire - Google Patents

Abstract

The present invention relates to a dual apex for a pneumatic tire, which increases a contact surface of a lower hard apex and an upper soft apex to increase a binding force of the two apexes to strengthen a unique function of an apex to supply a support force to a bead unit and prevent stress from being concentrated on an end of a carcass ply to improve durability of a tire. The dual apex for a pneumatic tire comprises: a hard apex (21) made of rubber having relatively high hardness and arranged on an upper side of a bead (25); and a soft apex (22) made of rubber having relatively low hardness and arranged on an upper side of the hard apex (21). An interface (23) between the hard apex (21) and the soft apex (22) has a Z-shape by two inflections.

Description

Dual Apex for Pneumatic Tire < RTI ID = 0.0 >

BACKGROUND OF THE INVENTION 1. Field of the Invention [0001] The present invention relates to a pneumatic tire for preventing the dispersion of beads constituting a bead portion of a pneumatic tire and mitigating the impact of beads, The present invention relates to a dual-apex of a pneumatic tire which enhances the durability of a tire by increasing the bonding force of the apex, thereby enhancing the inherent function of the apex to provide a bearing force to the bead portion and prevent stress from concentrating at the end of the carcass ply.

Generally, pneumatic tires are manufactured by mixing semi-finished products such as a cacass, a tread, a belt layer, an inner liner, etc. by mixing the rubber, A green case is made, the green case is put into a mold, and a certain temperature and pressure are applied to produce a finished tire.

Such pneumatic tires include an inner liner made of special rubber, a back-up liner supporting the inner liner to enhance the permeability of the air filled in the tire, In order to enhance the fatigue resistance against the repeated bending and stretching load, the movement of the carcass ply formed by the steel cord and the tread rubber forming the ground surface of the tire are minimized to improve the wear resistance, A side wall that protects the carcass ply, a belt that covers the cord end of the carcass ply and mounts the tire on the rim to prevent sudden deformation of the carcass ply A Bead Portion, a Chafer for reinforcing the bead portion, and an Apex positioned above the bead portion.

Here, the Apex minimizes the scattering of the beads constituting the bead, and alleviates the impact of the bead. As shown in FIG. 1, a carcass ply Is provided on the inner side of the bead portion (1) and above the bead portion (2).

On the other hand, when the vehicle is running, the tire is subjected to a repeated load action, so that the side portion of the tire constantly exhibits a bending action. As a result, permanent external force is applied to the bead portion for fixing the tire and the wheel.

Conventionally, the bead portion of the pneumatic tire is composed of a structure in which a bead made of a plurality of bead wires is covered with a rubber material having a very different elongation and strength, and is weak to a constant external force because of low binding force between the two materials. To compensate for this, the bead is reinforced with a reinforcing material having a bead reinforcing function such as apex, steel chafer, and rim flange to constitute the bead portion.

However, among the above-mentioned reinforcing materials, when the apex which directly contacts the bead does not play a role of minimizing the bead protection and the concentration of the end stress of the carcass ply, fatigue breakage due to tire rim desorption or end stress concentration occurs, It becomes impossible.

As a result, a dual apex has been developed in which the apex is divided into two portions, the lower portion is arranged with hard apex, and the upper portion is arranged with soft apex.

However, in the conventional dual apex, since the hard apex and the soft apex of the dual apex have different hardness and elongation, the binding force of the material at the interface between the two is weak and therefore the structure is weaker than the single structure apex, .

Meanwhile, as a result of investigation of the prior art related to the present invention, a large number of patent documents have been searched and some of them will be described as follows.

Patent Document 1 discloses a pneumatic tire in which an apte of a pneumatic tire is divided into a core portion that is the center portion and an outer portion that surrounds the core portion, and the core portion and the outer portion are formed of the same rubber composition. The core portion is formed of the vulcanized rubber composition, And the outer portion is formed of a non-vulcanized rubber composition so that the core portion is adhered well to other semi-finished products during the vulcanization of the tire, and after the tire vulcanization process, the core portion and the outer portion The present invention relates to a pneumatic tire improved in the bead portion by being integrated so as to have the same hardness so as to improve the durability of the bead portion by suppressing the separation generated in the apex during high speed running.

Patent Document 2 discloses a middle load tire comprising a bead portion having a bead core and an apte and a body ply surrounding the bead portion so as to wrap up the bead portion. The outer portion of the turnup portion of the body ply is wrapped with a nylon cord, And the end of the nylon cord is configured to cover the end of the body fly to reduce the deformation energy and the heat generated at the end of the bead body fly to improve the durability of the bead portion, A middle-load pneumatic tire is described.

KR 2011-0045615 A KR 2013-0075199 A

SUMMARY OF THE INVENTION The present invention has been conceived to solve the problems of the prior art described above, and it is an object of the present invention to increase the contact area between a hard apex and a soft apex to improve the binding force therebetween, So that the durability of the tire can be improved.

In order to accomplish the above object, the present invention provides an airbag apparatus comprising: a hard apex formed of a rubber having a relatively high hardness and disposed on an upper side of a bead; and a soft apex formed of a rubber having a relatively low hardness and disposed above the hard apex In the dual-apex of the mouth tire, the interface between the hard apex and the soft apex has an alphabet Z shape through two inflections.

According to the dual-apex of the pneumatic tire of the present invention, the interface has a first portion formed at an angle of 45 degrees with respect to the width direction, and a second portion formed at a direction perpendicular to the width direction, And a third portion formed at an angle of 45 degrees with respect to the width direction and connected to an upper end of the second portion.

According to the dual-apex of the pneumatic tire of the present invention, when the width of the interface starting point is L, the width W of the first portion is L / 2 and the length L2 of the second portion is W / 2 .

In the dual-apex of the pneumatic tire of the present invention, since the interface between the hard apex and the soft apex is formed in the alphabet Z shape, the contact area between the hard apex and the soft apex is increased so that the bonding force between the hard apex and the soft apex is structurally stabilized, Thereby enhancing the durability of the tire by reinforcing the function inherent to Apex, which provides a bearing force to the bead portion and prevents stress from concentrating on the end of the carcass ply.

According to the dual-apex of the pneumatic tire of the present invention, since the first portion and the third portion of the interface between the hard apex and the soft apex are formed to be inclined at an angle of 45 degrees with respect to the width direction, the contact area between the hard apex and the soft apex Is further increased.

BRIEF DESCRIPTION OF THE DRAWINGS Fig. 1 is a reference drawing showing a bead portion of a general pneumatic tire. Fig.
Fig. 2 is a view showing a dual-apex of a pneumatic tire according to the present invention. Fig.
3 is an enlarged view showing an Apex interface, which is a main part of the present invention.
4 is a reference diagram for explaining the structure of the Apex interface, which is a main part of the present invention.

Hereinafter, a dual-apex of a pneumatic tire according to the present invention will be described with reference to the accompanying drawings.

As shown in FIGS. 2 to 4, the dual-apex of the pneumatic tire according to the present invention includes a hard apex 21 formed of rubber having a relatively high hardness and disposed on the upper side of the bead 25, And a soft apex 22 formed of low rubber and disposed on the upper side of the hard apex 21. The interface 23 between the hard apex 21 and the soft apex 22 is bent twice, Shape.

Specifically, the interface 23 includes a first portion 23a formed at an angle of 45 degrees with respect to the width direction of the APEX 20, a first portion 23a formed in a direction perpendicular to the width direction of the APEX 20, A second portion 23b connected to an end of the first portion 23a and a third portion 23c formed at an angle of 45 degrees with respect to the width direction of the apte 20 and connected to the upper end of the second portion 23b, (23c).

The width W of the first portion 23a is L / 2 and the length L2 of the second portion 23b is W / 2, where L is the width of the starting point of the interface 23 desirable.

Reference numeral 10 denotes an inner liner, reference numeral 20 denotes a carcass ply, and reference numeral 26 denotes a steel cage.

The dual-apex of the pneumatic tire of the present invention having the above-described structure forms the boundary surface between the hard apex and the soft apex in an alphabet Z shape to increase the contact area between the hard apex and the soft apex, Avoid separation between Apex at high speed.

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, but, on the contrary, It will be appreciated by those of ordinary skill in the art that numerous changes and modifications can be made to the invention without departing from the spirit and scope of the invention. And all such modifications and changes as fall within the scope of the present invention are therefore to be regarded as being within the scope of the present invention.

10 ... Inner Liner
15 .... Carcass fly
20 ... Dual Apex
21 ... Hard Apex
22 ... Soft Apex
23 ... interface
23a ... first part
23b ... second part
23c ... third part
25 ... bead
26 ... steel chaffer
L ... width of the starting point of the boundary
W ... width of the first part
L2 ... length of the second part

Claims (3)

A hard apex 21 formed of rubber having a relatively high hardness and disposed on the upper side of the bead 25 and a soft apex 22 formed of rubber having a relatively low hardness and disposed above the hard apex 21, A dual-aisle pneumatic tire according to claim 1,
The interface 23 between the hard apex 21 and the soft apex 22 has an alphabet Z shape through two turns,
The interface 23 has a first portion 23a formed at an angle of 45 degrees with respect to the width direction of the APEX 20 and a second portion 23a formed in a direction perpendicular to the width direction of the APEX 20, A second portion 23b connected to the end of the portion 23a and a third portion 23c formed at an angle of 45 degrees with respect to the width direction of the apex 20 and connected to the upper end of the second portion 23b, Lt; / RTI >
When the width of the starting point of the interface 23 is L,
The width W of the first portion 23a is L / 2,
And the length L2 of the second portion 23b is W / 2. delete delete

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