JP2007182140A - Pneumatic radial tire - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To propose a pneumatic radial tire capable of improving maneuverability and riding comfort without impairing the durability of a carcass. <P>SOLUTION: This pneumatic tire is provided with a pair of bead cores 1, the carcass 2 toroidally extending from one of the bead cores 1 to the other and made of at least one sheet of ply having a folded part 1a folded around the bead cores 1, and a reinforcing rubber member (bead filler) 3 arranged at the inside of a folded part 2a of the carcass 2. The carcass 2 becomes a cord array parallel to a rotary shaft of a tire in the deploying state, has only a region w along the reinforcing rubber member 3 to have an angle θ of 5 to 15° in relation to the rotary shaft and exists in the range of 0 to 40% of a tire sectional height H. A reinforcing layer 4 having an organic fiber or steel cord intersecting a carcass cord at an angle θ<SB>1</SB>of 20 to 70° in relation to the rotary shaft of the tire and having the height h to be ≤35% of the tire sectional height H is provided between the carcass 2 and the reinforcing member 3. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a pneumatic radial tire, and is intended to improve both maneuverability and ride comfort at the same time without impairing carcass durability.

  FIG. 1 is a perspective view schematically showing the appearance of a tire. In general, when the carcass is angled, it is possible to increase the lateral rigidity and the longitudinal rigidity of the tire as shown in the figure, which can improve the maneuverability but also increase the vertical rigidity. There is a drawback that the ride comfort deteriorates, and if a configuration in which the angled parts are arranged adjacent to each other, shearing force works on that part, separation occurs and the durability of the carcass deteriorates. well known.

  On the other hand, if the carcass angle is 0 ° (arranged parallel to the tire's rotation axis), the longitudinal rigidity will be low and the riding comfort can be improved, but the lateral rigidity and the longitudinal rigidity will be low. Because the steering stability is inferior, it is necessary to increase the volume of the bead filler to cover this, or to add a bead reinforcement such as nylon, which increases the tire weight and the manufacturing cost. There was an inevitable drawback.

As prior art in this regard, high-speed durability is achieved by making the angle of the carcass cord with respect to the tire circumferential direction different between a belt restraint region restrained by the belt layer and a non-restraint region not restrained by the belt layer. There has been proposed a pneumatic tire that is intended to prevent the deterioration of the ride comfort while improving it (see, for example, Patent Document 1). It was the current situation.
JP 2001-354013 A

  An object of the present invention is to propose a pneumatic radial tire that can improve the maneuverability and the ride comfort without impairing the durability of the carcass.

The present invention provides a pair of bead cores, a carcass composed of at least one ply extending in a toroidal shape from one of the bead cores to the other and having a folded portion folded around the bead core, and the folding of the carcass A pneumatic radial tire provided with a reinforcing rubber member (bead filler) disposed inside the portion,
The carcass has a cord arrangement parallel to the rotation axis of the tire in its unfolded state, but only the region along the reinforcing rubber member is at an angle of 5 to 15 ° with respect to the rotation axis, and the tire cross section Exists in the range of 0-40% of the height,
Between the carcass and the reinforcing rubber member, there is an organic fiber or a steel cord that intersects the carcass cord at an angle of 20 to 70 ° with respect to the rotation axis of the tire, and the height h is the tire cross-sectional height H. This is a pneumatic radial tire characterized by having a reinforcing layer that is 35% or less.

  By making the carcass cord angle 5 to 15 ° in the area where the reinforced rubber is involved, the rigidity of that portion is increased, and the cord angle is 0 ° in other regions, so it is easy to bend and improves maneuverability and ride comfort It becomes possible to make it.

  The carcass cord is angled in the region along the reinforcing rubber including the carcass folding part, but there is a reinforcing rubber member such as a bead filler inside, so those parts are folded back to the area before the folding. There is no direct contact in the region, the interlaminar shear strain can be significantly reduced, and durability can be improved.

  In particular, between the carcass and the reinforcing rubber member, there is an organic fiber or steel cord that intersects the carcass cord at an angle of 20 to 70 ° with respect to the rotation axis of the tire, and the height h is the tire cross-sectional height. By providing a reinforcement layer that is 35% or less of the height H, the lateral rigidity and the longitudinal rigidity of the tire are further increased, and further maneuverability can be improved.

Hereinafter, the present invention will be described more specifically with reference to the drawings.
FIG. 2 shows a pneumatic radial tire according to an embodiment of the present invention in a left half section. In the figure, 1 is a pair of bead cores on the left and right, and 2 is a carcass extending in a toroidal shape from one side of the bead core 1 to the other. The carcass 2 is composed of at least one ply having a folded portion 2 a that is folded around the bead core 1. Further, 3 is a bead filler as a reinforcing rubber member disposed inside the folded portion 2a of the carcass 2, and 4 is a reinforcement layer (bead) disposed between the carcass 2 and the bead filler 3 inside the bead filler 3. Reinforcement layer).

  As shown in FIG. 3, the carcass 2 has a cord arrangement parallel to the rotation axis L of the tire, but only the region w along the reinforcing rubber member 3 of the folded portion 2 a is the tire. An angle θ of 5 to 15 ° with respect to the rotation axis L is present, and a region w of this angle θ exists in a range of 0 to 40% of the tire cross-section height H (section height).

Further, as shown in the figure, the cord of the reinforcing layer 4 intersects the carcass cord at an angle θ _{1 of} 20 to 70 ° with respect to the tire rotation axis L, and the height h is the tire cross-sectional height H. Less than 35%. Here, as the reinforcing layer 4, specifically, a ribbon-like layer having a thickness of about 0.5 to 2.0 mm in which organic fiber cords or steel cords are arranged and covered with rubber can be used. 4 may be a single layer, or a stacked structure in which two or more layers are stacked.

  FIG. 4 schematically shows the arrangement of the bead core 1, the reinforcing rubber member 3, the cord of the carcass 2 and the reinforcing layer 4 with respect to the main part.

  5, FIG. 6 (a) (b) and FIG. 7, FIG. 8 (a) (b) show other embodiments of the pneumatic radial tire according to the present invention, respectively.

  5, 6 (a), and 6 (b) are examples in which the reinforcing layer 4 is disposed between the bead filler 3 and the carcass 2. By arranging the reinforcing layer 4 on the outside of the bead filler 3 as shown in the figure, the lateral rigidity and the longitudinal rigidity of the tire can be increased, and the maneuverability can be improved.

  7, 8 (a) and 8 (b) are examples in which a wide reinforcing layer 4 is arranged from the inside to the outside of the bead filler 3. The reinforcing layer 4 can also be arranged from the inside to the outside of the bead filler 3 as shown in the figure, and this can increase the lateral rigidity and the longitudinal rigidity of the tire without impairing the durability of the carcass. .

  Manufactured pneumatic radial tires of size 205 / 60R15 91H with the following structure, assembled on wheels with a rim size of 15x6J and mounted on a 1800cc FF vehicle, handling on dry roads In addition to evaluating the feeling of riding comfort, we investigated the durability of the tires. The results are compared and shown in Table 1.

  The durability of the tire is as follows. The above tire is assembled to a wheel with a rim size of 15 x 6 J, the internal pressure is 240 kPa (JATMA maximum internal pressure), and it is pressed against a steel drum with a diameter of 1.7 m with a load of 615 kg (JATMA maximum load) The distance traveled until the tire broke down after rotating at a speed of 60 km / h was evaluated and the longer the distance traveled, the better the durability. In addition, the maneuverability and ride comfort were rated as 10 out of 10 and the higher the value, the better the performance.

Tire structure conformity example 1 (Figs. 2, 3, and 4)
It has a carcass where the angle θ of the cord in the area along the bead filler in the folded portion is set to 10 °, and the angle of the other area is set to 0 ° (change the angle in the cord axis direction). during (folded thickness 1.0mm before area (inner bead filler), height H25mm, 20% of the reinforcing layer of the tire section height H at an angle theta ₁ of 45 ° to the rotation axis L of the tire (organic An arrangement of fiber cords).

Application example 2 (Fig. 5, Fig. 6 (a) (b))
It has a carcass where the angle θ of the cord in the area along the bead filler in the folded part is 10 ° and the angle of the other area is set to 0 ° (change the angle in the cord axis direction), and between the carcass and the bead filler (thickness 1.0mm in the region (outside of the bead filler) after folding, height H25mm, 20% of the reinforcing layer of the tire section height H at an angle theta ₁ of 45 ° to the rotation axis L of the tire (organic fibers The arrangement of the code).

Application example 3 (Fig. 7, Fig. 8 (a) (b))
It has a carcass where the angle θ of the cord in the area along the bead filler in the folded portion is set to 10 °, and the angle of the other area is set to 0 ° (change the angle in the cord axis direction). Between (before and after turning back) (inside to outside of the bead filler), the thickness is 1.0 mm, the height h ₁ = 25 mm, h ₂ = 15 mm, and the angle θ ₁ of 45 ° with respect to the tire rotation axis L. A 20% and 12% reinforcement layer (with organic fiber cords arranged) of the tire cross-section height H.

Comparative Example 1 (FIGS. 9 (a) (b))
A carcass with a cord angle of 0 ° over the entire length (without changing the angle in the cord axis direction).

Comparative Example 2 (Fig. 10 (a) (b))
The cord angle is 10 ° over the entire length (without changing the angle in the cord axis direction) with a carcass.
Comparative Example 3 (FIGS. 11 (a) (b))
It has a carcass where the angle θ of the cord in the area along the bead filler in the folded portion is set to 10 °, and the angle of the other area is set to 0 ° (change the angle in the cord axis direction). No reinforcement layer between them.

  As can be seen from Table 1, although the fit example 1 is slightly inferior to the comparative tire 1, the maneuverability is remarkably improved and the drum travel distance (durability) is also equivalent. In addition, the maneuverability is improved as compared with Comparative Example 2, the ride comfort and the drum travel distance are remarkably improved, and the maneuverability is improved although the ride comfort is slightly inferior compared with Comparative Example 3. The drum mileage was almost the same.

  In the conforming example 2, although the riding comfort is slightly inferior to the comparative tire 1, the maneuverability is remarkably improved, and the drum travel distance (durability) is also equal. In addition, the maneuverability is improved as compared with Comparative Example 2, the ride comfort and the drum travel distance are remarkably improved, and the maneuverability is improved although the ride comfort is slightly inferior compared with Comparative Example 3. The drum mileage was almost the same.

In the conforming example 3, although the ride comfort is slightly inferior to the comparative tire 1, the maneuverability is remarkably improved, and the drum travel distance (durability) is also equal. In addition, the maneuverability is improved as compared with Comparative Example 2, the ride comfort and the drum travel distance are remarkably improved, and the maneuverability is improved although the ride comfort is slightly inferior compared with Comparative Example 3. The drum mileage was almost the same.

  A pneumatic radial tire with improved maneuverability and ride comfort can be provided without impairing carcass durability.

It is the perspective view which showed the external appearance of the pneumatic tire typically. It is the figure which showed embodiment of the pneumatic radial tire according to this invention in the cross section of the left half. FIG. 3 is a development view (plan view) of the carcass of the tire shown in FIG. 2. It is the figure which showed the arrangement | positioning condition of the reinforcement rubber member of the tire shown in FIG. 1, and the code | cord | chord of a carcass. It is the figure which showed other embodiment of the pneumatic radial tire according to this invention. (a) (b) is the figure which showed other embodiment of the pneumatic radial tire according to this invention. It is the figure which showed other embodiment of the pneumatic radial tire according to this invention. (a) (b) is the figure which showed other embodiment of the pneumatic radial tire according to this invention. (a) is the figure which showed the arrangement | positioning condition of the reinforcing rubber member of the comparative tire 1, a bead core, and a carcass (cord), (b) is a development view of a carcass. (a) is the figure which showed the arrangement | positioning condition of the reinforcement rubber member of the comparative tire 2, a bead core, and a carcass (code | cord), (b) is a development view of a carcass. (a) is the figure which showed the arrangement | positioning condition of the reinforcing rubber member of the comparative tire 3, a bead core, and a carcass (cord), (b) is a development view of a carcass.

Explanation of symbols

1 Bead core 2 Carcass
2a Turn-up part 3 Reinforcement rubber member 4 Reinforcement layer (bead reinforcement layer)
w A region L along the reinforced rubber member of the folded portion L Tire rotation axis H Tire cross-section height (section height)

Claims (1)

A pair of bead cores, a carcass composed of at least one ply that extends in a toroidal shape from one of the bead cores to the other and has a folded portion around the bead core, and an inside of the folded portion of the carcass A pneumatic radial tire provided with a reinforced rubber member disposed;
The carcass has a cord arrangement parallel to the rotation axis of the tire in its unfolded state, but only the region along the reinforcing rubber member is at an angle of 5 to 15 ° with respect to the rotation axis, and the tire cross section Exists in the range of 0-40% of the height,
Between the carcass and the reinforcing rubber member, there is an organic fiber or a steel cord that intersects the carcass cord at an angle of 20 to 70 ° with respect to the rotation axis of the tire, and the height h is the tire cross-sectional height H. A pneumatic radial tire characterized by having a reinforcing layer that is 35% or less of the above.

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