JP3133156B2 - Pneumatic radial tire - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to air which is formed at a radially inner end of a pair of sidewalls extending radially from both ends of an annular tread portion and which reinforces an annular bead portion fitted to a rim. Radial tires.

[0002]

2. Description of the Related Art An ordinary pneumatic radial tire is formed at an annular tread portion provided with a belt, a pair of sidewall portions extending radially from both ends of the tread portion, and a radially inner end of the sidewall portion. An annular bead portion fitted to the rim, and a carcass ply extending radially through the tread and the sidewall portion and having both ends wound around a bead core in the bead portion. Recently, as the performance of a vehicle has become higher, such as a higher speed or a higher output, a radial tire has also been required to have higher maneuverability, stability, and a higher load-bearing ability under a high load. It is known that a reinforcing layer composed of a fiber layer is additionally provided separately from the carcass ply cord from the bead portion or the bead portion to the sidewall portion, and the distance t from the tire surface to the reinforcing layer is known.
It was set so as to exceed 40% of the total thickness T of the same portion.

[0003]

However, in the conventional pneumatic radial tire described above, since a new member is added as a reinforcing layer, the rolling resistance is increased as a result of an increase in the tire weight, and the riding comfort performance is increased. There was a problem that it became worse. Further, a total gauge T, which is the thickness (total thickness) between the outer surface and the inner surface of the tire at a portion where the reinforcing layer is provided from the bead portion to the sidewall portion.
Becomes larger, the deflection allowance when the tire is deformed decreases,
When the tire is greatly deformed in the radial direction at the time of large input or heavy load, the rim touch (see FIG. 5) in which the inner surface of the sidewall contacts the inner surface of the tread portion is likely to occur, so that the rim touch easily breaks over a bump on the road surface. And
In particular, there is a problem that it is remarkable in a tire having a small flatness (60% or less).

SUMMARY OF THE INVENTION An object of the present invention is to solve the above-mentioned problems, to increase the tire rigidity, secure the tire deflection allowance, and increase the load without increasing the weight of the tire and without increasing the total gauge. An object of the present invention is to provide a pneumatic radial tire with improved load capacity.

[0005]

A pneumatic radial tire according to the present invention has an annular tread portion, a pair of sidewalls extending from both ends of the tread portion in the tire radial direction, and a sidewall formed at the radial inner end of the tire. An annular bead portion fitted to the rim, a carcass penetrating the tread portion and the sidewall, and having an end wound up around a bead core disposed in the bead portion, and a tire radius along the carcass from the bead core. In a pneumatic radial tire having a bead apex extending outward in the direction, the bead portion or the bead portion between the bead apex and the carcass winding portion is arranged in parallel from the bead portion to the sidewall portion. A reinforcing layer made of a plurality of reinforcing layer cords (for example, steel cords) provided from the outer end of the rim flange. 0.15 ≦ h / H ≦ 0.60 is established between the distance (reinforcement layer height) h from the tire radial outer end to the distance (tire height) H from the rim flange outer end to the tire outer peripheral end, The thickness t from the tire outer surface to the reinforcing layer at the position of the distance L from the outer end of the rim flange to the tire radially outward, and the thickness from the tire outer surface to the inner surface at the position of the distance L, that is, the total gauge T. Between 0.1 h <L
<With 0.05 ≦ t / T ≦ 0.35 is formed to stand in a range of 0.5 h, the reinforcing layer cords and Kakasupura
Cord angle θ with the cord in the range of 30 to 80 °.
The reinforcing layer core at the radially inner end of the reinforcing layer in the tire
Inner angle θ1 between the cable and the carcass ply cord,
Reinforcement layer cord at tire radially outer end of reinforcement layer
Smaller than the outer end angle θ2 between the
(Θ1 <θ2) Is the cord angle θ the inner end angle θ1?
To the outer end angle θ2
Thus, it is possible to increase the tire rigidity, secure the allowance of the tire deflection, and improve the load-bearing capacity without increasing the weight of the tire and without increasing the total gauge. In addition to improving ride comfort,
Drivability, especially steering wheel responsiveness, can be improved.

[0006]

An embodiment of the present invention will be described with reference to the drawings. In FIG. 1, a pneumatic radial tire to which the present invention is applied includes an annular tread 1, a pair of sidewall portions 2 extending in the tire radial direction from both ends of the annular tread 1, and a tire radially inner end of the sidewall portion 2. Penetrating the formed annular bead part 3, the bead core 4 embedded in the bead part 3, the annular tread 1 and the sidewall 2,
A one-ply carcass 5 whose end is wound up from the inside of the tire to the outside around the bead core 4 in the beat portion 3, and a tapered rubber layer extending from the bead core 4 along the carcass 5 and extending outward in the tire radial direction. A bead apex 6 comprising a bead core 4 and a bead apex 6 extending from the bead portion 3 or the bead portion 3 to the side wall portion 2 and from the tire outside the bead apex 6 to the carcass 5, ie, the bead core 4 and the bead. A reinforcing layer 7 composed of a plurality of fiber cords arranged in parallel with each other between the apex 6 and the winding portion of the carcass 5, and a belt layer 8 provided outside the acus ply 5 of the tread 1. I have.

When a load is applied to the tire, the tire is deformed to be compressed in the radial direction of the tire. Therefore, in the bead portion 3 or its vicinity (the range where the reinforcing layer 7 is provided), a tensile force is applied inside the tire. Compressive force acts on the outer side of the tire, and it is good to arrange the reinforcing layer near the surface where the largest force is applied, that is, where the distortion is the largest. It is preferable to place the reinforcing layer near the inner surface of the bead core 4 and the bead apex 6. Since the carcass 5 is provided and the ply cord constituting the carcass 5 has a sufficient strength against tension, the reinforcing layer 7 is provided only on the outside of the tire.
As a reinforcing layer cord constituting the reinforcing layer 7, a cord made of a material having high strength against a compressive force, that is, a material having a high compression modulus, for example, a steel cord is used.

In FIG. 2, the rim 9 includes a bead seat 90 into which the bead portion 3 is fitted, and a rim flange 91 extending outward from the bead seat 90 and outward in the tire radial direction.
Tire height which is the distance in the tire radial direction from the outer end of the rim flange 91 to the outer peripheral end of the tread portion 1 (that is, the tire radius which is the distance from the bead seat 90 to the outer peripheral end of the tread portion 1; From the outer edge of the rim flange 91 to the outer edge of the rim flange 91), and the outer edge 71 of the reinforcing layer 7 from the outer edge of the rim flange 91 to the tire radial outer edge 71.
The reinforcing layer height h, which is the distance in the tire radial direction up to, has the following relationship. 0.15 ≦ h / H ≦ 0.60

At a position of a distance L from the outer end of the rim flange 91 outward in the tire radial direction, a thickness t from the tire outer surface to the reinforcing layer 7 and a thickness t from the tire outer surface to the inner surface at the position of the distance L. The thickness, that is, the total gauge T has the following relationship. In the range of 0.1 h <L <0.5 h, 0.05 ≦ t / T ≦ 0.
35

[0010] With the above configuration, it is possible to increase the tire rigidity, secure the allowance for the tire deflection, and improve the load-bearing capacity without increasing the weight of the tire and without increasing the total gauge.

For example, in a tire having a conventional reinforcing layer, t / T = 0.4 to 0.6, and the position of the reinforcing layer is set to 0.1 h without changing the total gauge T of the conventional tire.
In the range of <L <0.5 h, when moving to 0.05 ≦ t / T ≦ 0.35, the deflection allowance before reaching the rim touch does not change, but the tire spring constant increases and the maneuverability during turning etc. improves. At the same time, the absorbed energy up to the rim touch is increased, so that the possibility of damaging the vehicle side when climbing over a protrusion or the like is reduced. Further, when the total gauge T of the tire is reduced to have the same tire spring constant as the conventional tire, the tire weight is reduced, the rolling resistance is reduced, and the riding comfort is improved, and Since the bending allowance increases, the absorbed energy increases.

Next, Table 1 shows experimental results obtained by using Examples 1 and 2 which are pneumatic radial tires to which the present invention is applied and a conventional example which is a tire provided with a conventional reinforcing layer. The tire size is 195 / 60R15 87H T / L. For the maneuverability, ride comfort, and rolling resistance in the table,
The performance is indicated by an index, and the larger the index, the better the performance.

[Table 1] Conventional Example Example 1 Example 2 h / H 0.42 0.40 0.42 t / T 0.45 0.21 0.22 T (index) 100 99 85 Maneuverability (index) ) 100 108 100 Ride comfort (index) 100 100 105 Rolling resistance (index) 100 101 105 Absorbed energy (index) 100 121 123

As shown in FIG. 3, the reinforcing layer cords 70 forming the reinforcing layer 7 are arranged parallel to each other so as to form a predetermined cord angle θ with respect to the carcass ply cord 50. The cord angle θ is in the range of 30 to 80 °, and the inner end angle θ ₁ between the reinforcing layer cord 70 and the carcass ply cord 50 at the radially inner end of the reinforcing layer 7 is determined by the tire radius of the reinforcing layer 7. The outer end angle θ ₂ between the reinforcing layer cord 70 and the carcass ply cord 50 at the outer end in the direction is made smaller (θ ₁ <θ ₂ ), and the cord angle θ is changed from the inner end angle θ ₁ to the outer end angle θ ₂ . Increase gradually and continuously. Therefore, the code angle θ is θ ₁ ≦ θ ≦ θ ₂
And 30 ° ≦ θ ₁ <θ ₂ ≦ 80 ° holds.

According to this configuration, by reducing the inner end angle θ ₁ of the inner end in the tire radial direction of the reinforcing layer 7,
The longitudinal rigidity of the bead portion 3 is increased to prevent rim touch. Also, by increasing the outer end angle θ ₂ of the tire radially outer end of the reinforcing layer 7, an increase in longitudinal rigidity near the center of the sidewall portion 2 is suppressed, and deterioration of ride comfort is prevented, And the maneuverability by increasing the tire circumferential rigidity,
In particular, handle responsiveness can be improved.

In the above-described embodiment, the tire provided with the one-ply carcass 5 has a winding end of the carcass 5.
51 is positioned radially outward of the tire radial outer end 71 of the reinforcing layer 7, that is, higher than the upper end of the bead apex 6 (HTU), and the bead core 4 and the bead apex 6 and the carcass 5 Although the reinforcing layer 7 is provided between the winding portion and the winding portion (see FIG. 4A), the reinforcing layer 7 may be provided outside the tire at the winding portion of the carcass 5 (FIG. 4B). ), The winding end 51 of the carcass 5 was positioned lower than the upper end of the bead apex 6 (L
TU) (see FIG. 4C).

Further, in the tire having the two-ply carcass 5 composed of the carcass plies 5A and 5B, the winding end 51A of the inner carcass ply 5A is positioned higher than the upper end of the bead apex 6, and the outer carcass ply 5B
The raised end 51B of the carcass plies 6 is positioned lower than the upper end of the bead apex 6 (see FIGS. 4D and 4F), and the raised end 51B of both carcass plies 5A and 5B is positioned lower than the upper end of the bead apex 6. There is one that is positioned higher (see FIG. 4E), and a reinforcing layer 7 is provided between the bead apex 6 and the winding portion of the carcass 5 (see FIG. 4D).
Alternatively, the reinforcing layer 7 is provided between the winding portions of the carcass plies 5A and 5B (see FIG. 4E), or the reinforcing layer 7 is provided outside the tire at the winding portions of the carcass plies 5A and 5B. (See FIG. 4F).

[0018]

Since the present invention is configured as described above, the following effects can be obtained. Without increasing the weight of the tire and without increasing the total gauge, the rigidity of the tire can be increased, the allowance for bending of the tire can be ensured, and the load carrying capacity can be improved. Further, by reducing the inner end angle of the tire radially inner end portion of the reinforcing layer, the longitudinal rigidity of the bead portion is increased to prevent rim touch. Furthermore, by increasing the outer end angle of the tire radially outer end of the reinforcing layer, it is possible to suppress an increase in longitudinal rigidity near the center of the sidewall portion, to prevent deterioration in ride comfort, and to improve tire circumferential direction. The rigidity can be increased to improve the maneuverability, especially the handle response.

[Brief description of the drawings]

FIG. 1 is a sectional view of a pneumatic radial tire of the present invention.

FIG. 2 is an enlarged sectional view of the pneumatic radial tire of the present invention.

FIG. 3 is a structural explanatory view of a pneumatic radial tire of the present invention.

FIG. 4 is an enlarged sectional view of a main part showing various different embodiments of the present invention.

FIG. 5 is an enlarged sectional view showing a rim touch.

[Explanation of symbols]

1 tread, 2 sidewall, 3 bead, 4 bead core 5 carcass, 6 bead apex, 7 reinforcing layer

Claims (1)

(57) [Claims] 1. A tread portion, a pair of sidewalls, a bead portion at a radially inner end of the sidewall of the tire, a carcass penetrating the tread portion and the sidewall, and having an end wound around a bead core. In a pneumatic radial tire provided with a bead apex extending radially outward from the bead core along the carcass, the bead apex and the carcass winding portion
A reinforcing layer consisting of a plurality of reinforcing layer cords arranged in parallel from the bead portion or the bead portion to the side wall portion, a distance h from an outer end of the rim flange to an outer end of the reinforcing layer, 0.15 ≦ h / H ≦ 0.60 is established between the outer end and the distance H from the outer peripheral end of the tire,
A thickness t from the tire outer surface to the reinforcing layer at a position of a distance L from the rim flange outer end to the tire radially outward,
0.1 h <L <0.5 h between the thickness from the tire outer surface to the inner surface at the position of the distance L, that is, the total gauge T
So that 0.05 ≦ t / T ≦ 0.35 is satisfied.
Forming, reinforcing layer cord and carcass ply cord
Cord angle θ between 30 and 80 °, and reinforcement
Layer cord and power at the radially inner end of the tire
The inner end angle θ1 with the waste ply cord is
Reinforcement layer cord and carcass at tire radially outer end
Smaller than the outer end angle θ2 with the splice cord.
(Θ1 <θ2), the cord angle θ is from the inner end angle θ1 to the outer end
A pneumatic radial tire characterized by gradually increasing continuously at an angle θ2 .