JP2644953B2 - Pneumatic tire - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION This invention provides a high-speed running tires, reducing the weight of the raised and the tire steering stability, moreover relates to a pneumatic tire that facilitate its molding.

[0002]

2. Description of the Related Art In recent years, highway networks have been improved, and passenger cars have been increased in speed, and passenger cars have also been increased in speed and load, and tires used in these vehicles have been developed. As a result, flat tires having a flat rate of 60% or less have been widely used. In addition, such a flat tire tends to have lower rigidity in the sidewall portion and the bead portion than in the tread portion, and has a problem that steering stability is poor.

Conventionally, in a tire aiming at high performance, as shown in FIG. 2, the structure of the carcass is such that a carcass a is formed using two carcass plies b, b, and each carcass ply b , B are wound up around the bead core d of the bead portion c in the same direction. If necessary, a reinforcing ply is interposed between the winding portions of the two carcass plies b, b to increase the rigidity.

[0004]

However, when the carcass has the above-mentioned 2-0 configuration and runs at high speed, the carcass is greatly deformed, and the steering stability is inferior due to low lateral, longitudinal and torsional rigidity. In addition, there is a problem that the weight of the tire increases due to the carcass configuration of 2-0.

[0005] The inventors of the present invention have made various efforts to solve the above problems.
Trial, as a result of repeated experiments, the b) carcass composed of two carcass plies, together with wound from the inner of which the one with the bead cores to the folded position higher outside, other one, down on the outside of its The above-mentioned problem is solved by using a so-called 1-1 structure. B) Further, the bead portion is reinforced by using two reinforcing layers and displaced up and down so that a rigid step does not occur in the sidewall portion. Thus, the present invention was completed.

[0006] The present invention relates to a flat tire enhances the rigidity of the bead portion holding the also steering stability and eliminates stress concentration at the bead portion of a pneumatic tire capable of improving the durability
It is intended to be provided .

[0007]

SUMMARY OF THE INVENTION According to the present invention, a bead core is formed from a tread portion to a sidewall portion through a sidewall portion.
Touch the main body and the bead core connected to the main body.
In fold from moreover the bead core outwardly from the tire axis direction inward along the outward surface of the bead apex extending upwardly
The first having the turned back portion of the high turn-up structure
The carcass ply, a second end where the lower end is cut off near the lower end of the bead core, passing between the folded portion and the outward surface of the bead apex from the tread portion to the sidewall portion.
A carcass ply, an inner reinforcing layer using a steel cord arranged between an outward surface of the bead apex and a second carcass ply and extending vertically in the radial direction, and
Carcass ply and structure of the first pneumatic tire according to comprise an outer reinforcing layer using steel cords extending in the radial direction vertically disposed between said folded portion of the carcass ply
It is made.

[0008]

The first carcass ply has a turn-up structure with a turn-up structure that turns along the outward surface of the bead apex, and the second carcass ply has the turn-up portion and the outward surface of the bead apex. And the lower end is interrupted at a position separated from the bead portion and upward through the gap. Thereby, the first and second carcass plies 1-1.
By forming the carcass having the above-described configuration and adopting the shell configuration, it is possible to increase the rigidity of the sidewall portion in the lateral direction, the front-rear direction, and further, the twist.

Further, the total length of the ply can be shorter than that of the conventional structure in which two carcass plies are folded in the same direction as shown in FIG. 2, and the carcass can be lightened accordingly.

Further, since the second carcass ply passes between the first carcass ply and the bead apex and the lower end thereof is interrupted near the lower end of the bead core without bending, the molding can be performed without lowering the force variation. Easy going.

In addition, since two inner and outer reinforcing layers using steel cords are arranged outside the bead apex, the sidewall portion and the bead portion can be effectively reinforced, and the steering stability can be further enhanced. Can be done.

As described above, according to the present invention, the above-mentioned components are organically integrated and integrated, so that even if the tire is a flat tire, the steering stability is improved and the weight is reduced, so that the high-speed tire is realized. In addition, it is possible to improve the high load resistance and to facilitate the molding of the tire, thereby achieving economical production.

[0013]

An embodiment of the present invention will be described below with reference to the drawings. In FIG. 1, the pneumatic tire is a flat tire 1 having a flatness of 60% or less in this example. The tire 1 has a tread portion 2 forming a tread surface 2A, and a tire radially inward from both sides thereof. It has a pair of extending sidewall portions 3 and a bead portion 4 extending inward of the sidewall portion 3.

The tire 1 has a tape extending from the tread portion 2 to the bead core 5 of the bead portion 4 through the sidewall portion 3.
A body part 7a and the bead core connected to the body part 7a;
A is folded along the outward surface 6a of the bead apex 6 extending from the inside to the outside and upward from the bead core 5.
First carcass ply and a turnup portion 7 b returned
9 and the outward surface 6 of the folded portion 7 and the bead apex 6 from the tread portion 2 to the side wall portion 3
a of the second carcass ply 10 extending downward between
And a carcass 8.

In this embodiment, a belt layer 15 is provided inside the tread portion 2 and outside the carcass 8, and a band layer 16 for preventing the lifting of the belt layer 15 is provided outside the belt layer 15. You. The bead apex 6 forms an elongated triangle formed of rubber harder than the sidewall rubber 17 forming the outer wall of the sidewall 3.

The first and second carcass plies 9, 10
Has a carcass cord in which organic fibers such as nylon, polyester, rayon, and aromatic polyamide are arranged in parallel to each other and inclined with respect to the tire equator C, and the first carcass ply 9 has a folded portion. is a so-called high turnup structure is positioned above the upper end of the tire maximum width point B of 7 b. The lower end of the second carcass ply 10 is interrupted near the lower end of the bead core 5, and the first and second carcass plies 9, 10 form a carcass 8 having a 1-1 HTU configuration. ing.

Between the bead apex 6 and the second carcass ply 10, an inner reinforcing layer 11 extending vertically in the radial direction is provided, and the folded portion 7 of the second carcass ply 10 and the first carcass ply 9 is provided. The outer reinforcing layers 12 extending up and down in the radial direction are respectively arranged between the two. Inside
The side and outer reinforcing layers 11 and 12 are sheet bodies formed by arranging steel cords side by side and covering the cords with topping rubber.

In this embodiment, the inner reinforcing layer 11 is
The lower end is located at a position 3 to 7 mm above the upper end of the bead core 5 and the upper end is
End of the heel where the outer surface 4a of the tire crosses the bead seat surface 4b
0.35 to 0.5 times the distance H of the tire height H starting from the bead base line L is a tire axial direction line passing through the H
It is located above the tip P of the bead apex 6 with R1 therebetween.

In the present embodiment, the lower end of the outer reinforcing layer 12 is positioned above the lower end of the inner reinforcing layer 11, and the upper end of the outer reinforcing layer 12 starts from the bead base line L. Distance HR of 0.4 to 0.6 times H
2 and above the upper end of the inner reinforcing layer 11 and below the upper end of the folded portion 7 of the first carcass ply 9.

When the upper end heights HR1 and HR2 of the inner and outer reinforcing layers 11 and 12 are higher than the above-mentioned values, the inner and outer reinforcing layers 11 and 12 having a high bending constant. This is because while the tires are close to the tread portion 2, the ride comfort is reduced, and when the value is smaller than the above value, it is difficult to increase the rigidity of the bead portion 4.

The bead portion 4 includes a main body portion 7a of the first carcass ply 9 and an inward surface 6 of the bead apex 6.
extends radially downward starting between is b, and moreover from the inside to the outside wrapped bead core 5, a lower end below the rewinder and upper end the reinforcing layer 11 along the outer facing surface 6a of the bead apex 6 And a bead reinforcing layer 14 having a rewinding portion 13 that is interrupted. The bead reinforcing layer 14 is a tough and flexible sheet body in which a fabric made of an organic fiber such as nylon or aromatic polyamide fiber is covered with a topping rubber. Enhance and reinforce.

Further, in this embodiment, the first and second carcass plies 9 and 10 forming the side wall portion 3 and the bead portion 4, the bead apex 6, the inner and outer reinforcing layers 11 and 12, and the bead reinforcement are provided. The heights of the lower end and the upper end of the layer 14 from the bead base line L are related as follows.

The lower end of the second carcass ply (HA) <the upper end of the winding portion of the bead reinforcing layer (HB) <the lower end of the inner reinforcing layer (HU1) <the lower end of the outer reinforcing layer (HU2) <the winding of the bead reinforcing layer Side upper end (HE) <Bead Apex tip (HP) <Inner reinforcing layer upper end (HR1) <Outer reinforcing layer upper end (HR2) <First carcass ply folded portion upper end (HC)

When formed at such a related height position, the bending rigidity of the bead portion 4 and the sidewall portion 3 can be gradually reduced from below to above, and as a result, a stress concentration portion is formed. Therefore, the occurrence of damage to the tire 1 can be effectively prevented.

The belt layer 15 includes a plurality of belt plies 15a in which organic fibers such as nylon, rayon, and aromatic polyamide fibers or steel cords are arranged parallel or inclined with respect to the tire equator C. They are formed together to increase the rigidity of the tread portion 2.

In this embodiment, a band layer 16 is disposed outside the belt layer 15 of the tread portion 2. Band layer 1
6, one or more sheets covering the entire surface of the belt layer 15;
In this example, the band ply is composed of two band plies 16a, 16a.

The band ply 16a is formed by spirally winding a long, narrow band ply in which an organic fiber cord such as nylon or aromatic polyamide fiber or a steel cord is covered with a topping rubber, in the circumferential direction of the tire.
The lifting of the belt layer 15 during high-speed running is prevented, the speed is increased, and the end of the belt layer 15 is prevented from peeling, so that the high load performance is improved and the durability is improved.

[0028]

[Specific Example] A tire (example) having a tire size of 225/50 ZR16 and having the structure shown in FIG. 1 was prototyped according to the specifications shown in Table 1, and its performance was tested. In addition, the tire of the conventional structure and the tire (comparative examples 1 to 4) other than the structure of the present invention were also tested together and their performances were compared.

The test method is as follows. a) Driving stability on a circuit Each test tire was mounted on a 3000cc class sports car, the vehicle was driven on a circuit course, and the judgment was made based on the driver's feeling. Displayed with. The larger the value, the better the stability. Table 1 shows the test results.

[0030]

[Table 1]

[0031]

As described above, the pneumatic tire of the present invention having the above-mentioned structure can improve the steering stability and reduce the weight of the tire during high-speed running, and can be easily formed and economically manufactured. Is possible.

[Brief description of the drawings]

FIG. 1 is a right half sectional view of a tire showing one embodiment of the present invention.

FIG. 2 is a sectional view showing a conventional technique.

[Explanation of symbols]

2 tread portion 2A tread surface 3 sidewall portion 4 bead portion 4a bead portion of the outer surface 4b bead seat surface 5 bead core 6 bead apex 6a outward surface 7a body section 7 b folded portion 8 carcass 9 first carcass ply 10 second Carcass ply 11 inner reinforcing layer 12 outer reinforcing layer 14 bead reinforcing layer C tire equator H heel end

 ──────────────────────────────────────────────────続 き Continuation of the front page (56) References JP-A-57-18503 (JP, A) JP-A-2-18104 (JP, A) JP-A-4-254206 (JP, A) JP-A-2- 24205 (JP, A) JP-A-62-4615 (JP, A) JP-A-2-286406 (JP, U) JP-A 64-63402 (JP, U) JP-A-2-155812 (JP, U) Hikaru Hei 3-197210 (JP, U) JP-B Hei 1-37281 (JP, B2)

Claims (2)

(57) [Claims] A main body extending from the tread to the bead core of the bead through the side wall; and a main body connected to the main body.
On the outside the Li Kui the bead cores from the axially inward
First carcass ply, the turnup portion and the bead fart sidewall portion from a tread portion having a folded portion of the in fold returned high turnup structure from duck the bead core along the outer facing surface of the bead apex extending upwardly A second carcass ply having a lower end cut off near the lower end of the bead core passing between the outward facing surface of the apex and a steel cord disposed between the outward facing surface of the bead apex and the second carcass ply and extending vertically in the radial direction; An inner reinforcing layer using the first and second carcass plies before the first and second carcass plies
A pneumatic tire having an outer reinforcing layer using a steel cord arranged between the folded portion and a vertically extending radial direction . 2. The inner reinforcing layer has a lower end located at a position 3 to 7 mm above the upper end of the bead core, and an upper end intersects the outer surface of the bead portion and the bead seat surface.
A distance from the bead base line, which is a tire axial line passing through the heel end H, by a distance of 0.35 to 0.5 times the tire height is located upward, and the upper end of the outer reinforcing layer is while is positioned above said upper end of the spaced Moreover inner reinforcing layer distance of 0.4 to 0.6 times the tire height from the base line, the bead portion includes a main body portion of the first carcass ply Starting from the inward facing surface of the bead apex
Wrapped Katsu Nobi bead core on along the outward face of addition the bead apex from the inside to the outside in the tire axial direction
Using an organic fiber cord with a rewinding part on the side
In addition to providing a bead reinforcing layer, the upper end of the rewind portion has a rewind portion interrupted below the lower end of the inner reinforcing layer, and furthermore, a bead reinforcing layer using a cord made of organic fibers is provided. the pneumatic tire of claim 1 wherein the.