KR101973273B1 - Penumatic Radial Tire - Google Patents

Abstract

The present invention improves the weight of a conventional pneumatic tire by applying a lightweight aplastic structure and a reinforced side rubber layer so as to increase the durability of the bead portion while maintaining the rigidity of the side portion and the bead portion, The present invention relates to an air-to-air radial tire which has improved handling performance and durability by preventing separation and dispersing the stress at the apex end,
The width of the apte 16 from the upper end of the bead portion to the end of the bead portion is narrowed to form the lightweight portion 16 'and the thickness of the sidewall 13 from the end of the apex 16 is the minimum The side wall reinforcing layer 17 is formed to extend along the interface of the carcass 14. The side wall reinforcing layer 17 is formed to extend along the interface of the carcass 14. [

Description

BACKGROUND OF THE INVENTION 1. Field of the Invention [0001]

The present invention relates to an air-inlet radial tire having enhanced durability of a bead portion while maintaining the rigidity of a side portion and a bead portion. The present invention improves weight reduction by applying a lightweight apex structure and a reinforced side portion rubber layer to a conventional pneumatic tire , An air inlet radial tire which maintains the rigidity of the side portion and disperses the stress at the apex end to prevent separation and increase the handling performance and durability.

As shown in Fig. 1, a general air-inlet radial tire includes a tread 1 as a portion in contact with the road surface, a carcass 3 as a skeleton of the tire, and a plurality of A side wall 4 for protecting the carcass and allowing the carcass to flexibly move, a bead portion 4 for mounting the tire on the rim of the wheel, (6), and an apte (5) made of a triangular rubber filler for relieving external impact and protecting the bead (6).

When the vehicle is running, the tire is subjected to repetitive 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. As a result, the bead separation of the tire is often caused by the stress concentration at the Apex tip, and various studies have been conducted to improve it.

To compensate for this, the bead is reinforced with a reinforcing material having a bead reinforcing function such as apex, rim flange, ply strip, and fabric insert.

However, the conventional techniques are accompanied by an increase in the rotational resistance due to the increase in the tire load due to the insertion of the stiffener and a manufacturing difficulty due to the additional equipment in the process.

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.

European Patent No. 3112189 discloses a structure in which a reinforcing layer having a thickness of 1 to 3 mm and a length of 60 to 80 mm is placed on the outer side of the body fly at a position of -10 mm at the Apex end to measure the performance of the torsional stiffness, . However, there is a problem that the bead subsurface occurs due to the stress concentrated at the apex tip.

European Patent No. 2379355 discloses that the DRR (turn up height) of a tire is 15% or more of SH, the DRB (apex height) is 20% or more of SH, the DRI (outer strip start height) (the difference between the height of the outer strip tip and the starting height) is greater than 25% of the SH, reducing the rolling resistance (RR). However, the outer strip of prior art 1 has a special modulus (modulus of elasticity) with an elastic modulus G 'of less than 15 MPa and a viscous modulus G "of G" [Mpa] <0.2 * G' [Mpa] The rubber compound must be manufactured as a rubber compound.

European Patent No. 3112189 European Patent No. 2379355

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 provide a rubber reinforced layer having high rigidity between a side kakas and a side rubber to maintain side rigidity and reduce weight by applying a lightweight apex And to provide an air-inlet radial tire that maintains rotational resistance performance of a tire to prevent deterioration of fuel consumption and complements handling performance.

It is another object of the present invention to provide an air-inlet radial tire in which durability of the bead portion is improved by suppressing stress concentration at the apex end.

According to an aspect of the present invention, there is provided an airbag device comprising: a tread portion that is in direct contact with a road surface; a sidewall that forms a side surface of the tire to improve ride comfort; an innermost liner provided on the innermost side of the tire to prevent leakage of air; A bead portion disposed between the lower portion of the tread portion and the inner liner for absorbing an impact caused by bending motion during running and supporting a load, a bead portion having an iron core shape for coupling the tire with the rim and wound around the end of the carcass, A pneumatic radial tire comprising a triple-shaped rubber filler positioned between a lower end of a wall and the bead portion to minimize dispersion of the bead portion and mitigate an external impact to protect the bead portion,

The side wall reinforcement layer is formed from the end of the apex to the point where the thickness of the side wall is the minimum, And the reinforcing layer extends along the interface of the carcass.

Further, according to the pneumatic radial tire of the present invention, the lower end of the side wall reinforcing layer partially overlaps the end of the apte, and the overlap interval is 5 mm or less (0 is not included).

In addition, according to the pneumatic radial tire of the present invention, the height (SAH) from the top of the bead to the starting point of the lightweight portion of the apex is 5 to 10 mm, the lightweight portion of the apex has a width of 2.5 mm or less, The total height of the apex is 20 to 30 mm.

Further, according to the pneumatic radial tire of the present invention, the rubber forming the lightweight portion of the apex has a rubber hardness of 70 to 95 obtained by a spring type hardness tester A specified in JIS K6253.

Further, according to the pneumatic radial tire of the present invention, the 100% modulus of the rubber forming the light weight portion of the apex is 5 to 7.5 MPa.

Further, according to the pneumatic radial tire of the present invention, the side wall reinforcing layer has a thickness of 0.5 to 1.5 mm and a length of 1.0 to 3.0 times the height (APH) of the apex.

Further, according to the pneumatic radial tire of the present invention, the hardness of the rubber forming the side wall reinforcing layer is greater than the hardness of the side wall rubber.

According to the pneumatic radial tire of the present invention, the rubber forming the side wall reinforcing layer has a rubber hardness of 70 to 95 obtained by a spring type hardness tester A specified in JIS K6253.

The air-mouth radial tire of the present invention is provided with the sidewall reinforcing layer from the end of the apex to the point where the thickness of the sidewall is the minimum, so that the side portion rigidity of the tire is maintained while the lightweight portion is formed in the upper layer of the ape The weight of the tire can be reduced, and the handling performance can be improved while maintaining the rotational resistance performance.

Also, the pneumatic radial tire of the present invention has an effect of improving the durability of the tire, such as the concentration of stress to the apex end is relaxed to prevent separation of the bead portion.

BRIEF DESCRIPTION OF THE DRAWINGS Fig. 1 is a schematic view showing a cross section of a general air-inlet radial tire. Fig.
BACKGROUND OF THE INVENTION Field of the Invention The present invention relates to an air-inlet radial tire,

Hereinafter, an air-inlet radial tire according to the present invention will be described with reference to the accompanying drawings. Also, the attached drawings are exaggerated or conceptually expressed in order to understand the present invention, and the sizes and shapes expressed therein are not limited thereto.

As shown in Fig. 2, the air-inlet radial tire according to the present invention includes a tread portion 11 which is in direct contact with a surface, a sidewall 13 which forms a side surface of the tire to improve ride comfort, An inner liner 12 installed at the lower end of the tread portion 11 to prevent leakage of air and a carcass (not shown) disposed between the lower portion of the tread portion 11 and the inner liner 12 for absorbing impacts caused by bending motion during running A bead portion 15 having an iron core shape in which the end of the carcass 14 is wound so as to engage the tire and the rim and a bead portion 15 positioned between the lower end portion of the side wall 13 and the bead portion 15 And an apex 16 made of a triangular rubber filling material for minimizing dispersion of the bead portion 15 and mitigating external impact to protect the bead portion 15, From a position spaced apart by a certain distance from the end The width of the sidewall 13 is narrowed to form the lightweight portion 16 'and extends along the interface of the carcass 14 from the end of the apex 16 to the point of minimum thickness of the sidewall 13 The side wall reinforcing layer 17 is formed.

The side wall reinforcing layer 17 is preferably a rubber layer disposed between the sidewall 13 and the carcass 14, which is formed of rubber having a relatively high hardness and undergoes bending motion, and has a thickness of 0.5 to 1.5 mm. If the thickness of the side wall reinforcing layer 17 is less than 0.5 mm, it is difficult to manufacture the tire in the extrusion equipment of the manufacturing process. If the thickness is more than 1.5 mm, the thickness of the rubber reinforcing layer increases.

The apte 16 has a relatively thin lightweight portion (not shown) from a position (SAH) spaced about 5 mm to 10 mm from the top of the bead portion 15, 16 '. It is preferable that the lightweight portion 16 'is a portion having a maximum thickness of 2.5 mm or less and a minimum thickness of 0.5 mm, and the thickness of the lightweight portion 16' is reduced toward the end. If the minimum thickness of the lightweight portion 16 'is less than 0.5 mm, it is difficult to assemble with the bead portion 15. If the maximum thickness exceeds 2.5 mm, the weight saving effect is insignificant, to be.

<Test Example>

In order to verify the effects according to the present invention, the performance was tested under various conditions. In the test, the conditions of Table 1 were applied and then the stress distribution (strain energy), the cornering coefficient (Cornering Coefficient and Vertical Spring Rate. In order to estimate the durability of the bead portion, the stress distribution of the apex was compared. The stiffness of the side portion to estimate the handling performance was compared with the vertical spring rate. The results are shown in Table 2.

Item Expansion pressure Rim width Rim diameter Vertical load shame 33 psi 6.5 inch 16 inch 474 kgf

For reference, the maximum stress value of the Apex tip shown in Table 2 is a value obtained by comparing the stress value at the end portion causing the separation in the Apex, and the maximum stress value of the Apex tip of Comparative Example 1 is 100. The larger the maximum stress value of the Apex end, the more stress is applied to the Apex end, which increases the probability of separation, so the lower the maximum stress value of the Apex end, the better. The vertical spring rate indicates a force of several kgf per 1 mm ² , and the higher the value of the vertical stiffness, the stronger the stiffness of the side portion. The Cornering Coefficient is the value obtained by dividing the transverse stiffness by the grounding load. Generally, the higher the value of the cornering coefficient, the better the handling performance.

&Lt; Comparative Example 1 &

The test was carried out on 205/55 R16 tires satisfying the current standard of international standard (ETRTO, TRA) and tires with 25 mm height Apex.

&Lt; Comparative Example 2 &

The other conditions were the same as in Comparative Example 1, and the tire was tested with a 25 mm high Apex tire equipped with a light weight portion on the upper side.

<Experimental Example 1>

A side wall reinforcing layer having a thickness of 1 mm and a hardness of 78 to 82 was attached from the end of the apex to the LP and a 15 mm height of apex having the light weight on the upper side was applied and the other conditions were the same as in Comparative Example 1 The test was conducted.

<Experimental Example 2>

The test was carried out with one tire in the same manner as in Experimental Example 1 except that the height of the Apex equipped with the lightweight portion on the upper side was 20 mm.

<Experimental Example 3>

The test was carried out with one tire in the same manner as in Experimental Example 1 except that the height of the Apex equipped with the lightweight portion on the upper side was 25 mm.

<Experimental Example 4>

The test was carried out with the same tire as in Experimental Example 1 except that the height of the Apex equipped with the light weight portion on the upper side was 30 mm.

<Experimental Example 5>

The test was carried out on one tire in the same manner as in Experimental Example 1 except that the height of the Apex equipped with the lightweight portion on the upper side was 35 mm.

<Experimental Example 6>

The same test as in Experimental Example 3 was applied to a tire which was applied with the side wall reinforcing layer overlapping 20 mm at the apex end.

<Experimental Example 7>

The same test as in Experimental Example 3 was applied to a tire which was applied with the side wall reinforcing layer overlapping 10 mm at the apex end.

<Experimental Example 8>

The same test as in Experimental Example 3 was carried out using a tire which was applied with the same apex and whose side wall reinforcing layer was extended up to 20 mm from the L.P.

<Experimental Example 9>

The same test as in Experimental Example 3 was carried out using a tire extended to the same position where the side wall reinforcing layer was raised 30 mm from the L.P.

<Experimental Example 10>

The same test as in Experimental Example 3 was carried out using a tire in which the same apex was applied and the side wall reinforcing layer was extended to a position 20 mm below the L.P.

&Lt; Experimental Example 11 &

The same test as in Experimental Example 3 was carried out using a rubber in which the same apex was applied and the hardness of the side wall reinforcing layer was 90 to 95. [

<Experimental Example 12>

The same test as in Experimental Example 3 was carried out using the same rubber as in Example 3, in which the hardness of the side wall reinforcing layer was 70 to 75. [

The hardness of the side wall reinforcing layer shown in Experimental Example 11 and Experimental Example 12 mentioned above means the rubber hardness obtained by the spring type hardness tester A type specified in JIS K6253.

Comparative Example 1
Comparative Example 2
Experimental Example 1
Experimental Example 2
Experimental Example 3
Experimental Example 4
Experimental Example 5
Experimental Example 6
Experimental Example 7
Experimental Example 8
Experimental Example 9 Experimental Example 10 Experimental Example 11 Experimental Example 12 APH (mm) 25 25 15 20 25 30 35 25 25 25 25 25 25 25 RLL / APH - - 4 2.7 1.9 1.4 One 2.5 2.5 2.8 3.2 1.1 1.9 1.9 Vertical stiffness 100 100 101 101 101 101 101 101 101 101 103 101 101 101 Cornering factor
100
100
101
101
101
101
101
101
101
102
102
100
101
101 Apex end maximum stress
100
134
108
97
76
146
129
66
74
76
74
78
76
76

Referring to Table 2, when the side wall reinforcing layer is applied to the lightened apex, the vertical stiffness and the cornering coefficient performance are improved. However, when the height of the lightened aptes (APH) is 15 mm, 30 mm and 35 mm, The maximum stress is concentrated at the apex end as indicated by 108, 146, and 129, which may cause a separation phenomenon. Therefore, by limiting the height of the lightened apex to 20 mm to 30 mm, it is possible to alleviate stress concentration at the apex end and to improve the durability of the bead portion.

According to the results shown in Table 2, not only the rubber hardness of the side wall reinforcing layer 17 is 80 but also the rubber hardness is 70 to 95 or less, the bead endurance and the rigidity of the side portion are improved have.

In addition, it has been confirmed that a series of performance is improved even when the side wall reinforcing layer 17 is longer or shorter on the basis of LP. Therefore, it is judged that the length RLL of the side wall reinforcing layer 17 is about 1 to 3 times as great as the height APH of the apex 16. If the length RLL of the side wall reinforcing layer 17 is less than 1 times the height APH of the apex 16, the reinforcing effect on the sidewall is insignificant. If the length RLL is more than 3 times, It is limited to 1 to 3 times.

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.

11 ... tread portion
12 ... Inner Liner
13 ... sidewall
14 ... Carcass
15 ... bead portion
16 ... Apex
16 '... Lightweight section
17 ... side wall reinforcing layer

Claims (8)

A sidewall 13 for forming a side surface of the tire so as to improve ride comfort, an inner liner 12 provided at the innermost portion of the tire for preventing leakage of air, A carcass 14 disposed between the lower portion of the carcass 14 and the inner liner 12 to absorb a shock caused by the bending motion during running and to support a load, This bead is located between the bead portion 15 in the form of an iron core and the bead portion 15 of the side wall 13 and minimizes the dispersion of the bead portion 15 and alleviates the external impact, (16) made of a triangular rubber filling material for protecting the air inlet radial tire
The apte 16 has a light weight portion 16 'having a width of a start point position of 5 mm to 10 mm away from the top of the bead portion 15 of 2.5 mm or less and a narrow width toward the end,
The rubber forming the lightweight portion 16 'is a rubber having a hardness of 70 to 95 and a 100% modulus of 5 to 7.5 MPa obtained by a spring type hardness tester A type specified in JIS K6253,
The total height of the apte 16 including the lightweight portion 16 'is 20 to 30 mm,
Of the rubber having a hardness of 70 to 95 obtained by the spring type hardness tester A type specified in JIS K6253 from the end of the light weight portion 16 'of the apte 16 to the point where the thickness of the side wall 13 is the smallest A side wall reinforcing layer 17 is formed extending along the interface of the carcass 14,
, The lower end of the side wall reinforcing layer (17) and the end of the lightweight portion (16 ') of the apex (16) overlap in a range of 5 mm or less (0 is not included). The method according to claim 1,
Wherein the side wall reinforcing layer (17) has a thickness of 0.5 to 1.5 mm and a length of 1.0 to 3.0 times the total height of the apex (16). The method according to claim 1 or 2,
Wherein the hardness of the rubber forming the side wall reinforcing layer (17) is greater than the hardness of the rubber forming the side wall (13). delete delete delete delete delete

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