JP7018308B2 - Pneumatic tires - Google Patents

Description

The present invention relates to a pneumatic tire.

Conventionally, a pneumatic tire in which a first ply and a second ply are arranged so that their cords intersect each other is known (see, for example, Patent Document 1).
Further, a pneumatic tire provided with a cord reinforcing layer having a plurality of cords extending in the tire circumferential direction on the outer side in the tread width direction of the carcass is known (see, for example, Patent Document 2).

However, the former pneumatic tire has a large weight because two plies are stacked. On the contrary, if the weight is reduced by using one ply, the desired rigidity cannot be obtained.
On the other hand, in the latter pneumatic tire, only the cord reinforcing layer is provided, and sufficient rigidity cannot be obtained as a whole.

Japanese Unexamined Patent Publication No. 2009-149187 Japanese Unexamined Patent Publication No. 2006-192953

An object of the present invention is to provide a pneumatic tire capable of increasing rigidity and improving steering stability performance.

The present invention provides means for solving the above problems.
Bead cores placed on both sides in the tire width direction,
A bead filler that is connected to the bead core and extends outward in the radial direction of the tire.
A carcass ply, which is made by covering a plurality of juxtaposed cords with a coating layer and hung over the bead core,
The belt wound on the outer side of the carcass ply in the tire radial direction,
A reinforcing layer arranged on the outer side of the bead filler in the tire width direction,
Equipped with
The carcass ply has a main body portion in which the cord extends along the meridian cross section, and a winding portion in which the cord is wound from the bead core to the outer surface side of the tire and the cord extends so as to intersect the cord of the main body portion when viewed from the tire width direction. ,
Equipped with
The winding portion is laminated on the outer surface of the main body portion of the bead filler and the reinforcing layer located on the outer side in the tire radial direction beyond the outer side in the tire radial direction .
The reinforcing layer cord provides a pneumatic tire that is inclined to the same side as the cord of the winding portion at an angle of 40 ° or more and 80 ° or less with respect to a straight line extending in the radial direction of the tire .

With this configuration, the cord of the main body and the cord of the winding portion laminated on the main body beyond the reinforcing layer intersect to obtain a tag effect, and the rigidity is obtained even though it is a single carcass ply. Can be enhanced. As a result, it becomes possible to improve the steering stability performance.

Further , the cord of the reinforcing layer and the cord of the winding portion can be crossed to exert a tag effect in this portion as well, and the rigidity can be increased.

It is preferable that the winding end of the carcass ply is laminated on the outer surface of the main body portion so as to exceed the bead filler by 10 mm or more outward in the radial direction of the tire.

With this configuration, it is possible to sufficiently secure the intersection range of the cords of the main body portion and the winding portion to exert the tag effect and increase the rigidity.

The winding ends of the carcass ply are preferably located within a range of up to 20 mm toward the center side in the tire width direction with respect to both ends of the belt in the tire width direction.

With this configuration, it is possible to suppress an increase in weight and prevent the binding force of the carcass ply from becoming too strong.

The angle between the cord of the reinforcing layer and the cord of the winding portion of the carcass ply is preferably 10 ° or more.

With this configuration, the reinforcing layer and the carcass ply cord can be crossed so as to obtain a sufficient tag effect.

According to the present invention, when the carcass ply is hung on the bead core, the winding portion is laminated on the main body portion beyond the reinforcing layer so that the cord of the main body portion and the cord of the winding portion intersect each other. It can be demonstrated. Therefore, even with a single carcass ply, it is possible to sufficiently increase the rigidity and improve the steering stability performance.

It is a meridian half sectional view of the pneumatic tire which concerns on this embodiment. It is a partial side view which shows the bead part and sidewall part of FIG. It is a partial side view which shows the bead part and sidewall part of the pneumatic tire which concerns on other embodiment.

Hereinafter, embodiments according to the present invention will be described with reference to the accompanying drawings. It should be noted that the following description is merely an example and is not intended to limit the present invention, its application, or its use.

FIG. 1 is a meridian semi-cross-sectional view of a pneumatic tire according to the present embodiment. In this pneumatic tire, bead cores 1 in which a plurality of wires are bundled are arranged on both sides of the WD in the tire width direction.

A bead filler 2 made of a rubber material for reinforcing the bead core 1 is arranged on the outer side of the bead core 1 in the tire radial direction.

A carcass ply 3 is hung on the bead core 1. A plurality of belts 4 and reinforcing belts 5 are wound around the outer side of the carcass ply 3 in the tire radial direction.

The outer side of the reinforcing belt 5 in the tire radial direction is a tread portion 6. Sidewall portions 7 are connected to both sides of the tread portion 6 in the tire width direction, and the bead portion 9 is formed from the top of the rim protector 8 to the bead core 1.

A chafer 10 is wound around the bead core 1 so as to cover the carcass ply 3 that has been hung. An inner liner 11 is provided on the inner surface side of the tire of the carcass ply 3.

A reinforcing layer 12 is provided on the outer surface of the main body 15 of the bead filler 2 and the carcass ply 3. The reinforcing layer 12 is formed by covering a plurality of steel reinforcing cords 13 arranged side by side at predetermined intervals with a rubber material.

Also referring to FIG. 2, the reinforcing cord 13 has a straight line extending in the tire radial direction (carcass cord 14a of the main body portion 15 of the carcass ply 3) in a direction opposite to the inclination direction of the carcass cord 14b of the winding portion 16. It is tilted at an inclination angle θ1. The inclination angle θ1 here is set in a range of 20 ° or more and 80 ° or less, preferably 60 °.

The carcass ply 3 has a toroid shape, and is composed of a plurality of carcass cords 14 arranged side by side at predetermined intervals coated with rubber. The carcass cord 14 is made of organic fibers such as nylon fibers. The carcass ply 3 includes a main body portion 15 arranged on the inner surface side of the tire, and a winding portion 16 that is folded back and wound up by the bead core 1.

In the main body 15, the carcass cord 14a extends at 0 °, that is, without an inclination angle, with respect to a straight line extending in the tire radial direction. In the winding portion 16, the carcass cord 14b is inclined at an inclination angle θ2 with respect to a straight line extending in the tire radial direction. The inclination angle θ2 here is set in a range of 10 ° or more and 50 ° or less, preferably 30 °.

Although the inclination angles θ1 and θ2 are defined as the linear directions extending left and right in the tire circumferential direction CD based on FIG. 2, they are actually in the circumferential direction. Therefore, the inclination angle θ1 is based on the lowermost end 12a of the reinforcing layer 12 on the inner side in the tire radial direction. That is, the straight line L1 extending in the tire radial direction RD is a straight line connecting the center of rotation of the tire and the position of the reinforcing cord 13 at the lowermost end 12a inside the tire radial direction RD of the reinforcing layer 12, and the straight line L The angle formed by the reinforcing cord 13 is defined as the inclination angle θ1. On the other hand, the inclination angle θ2 is based on the lowermost end 1a of the bead core 1. That is, the straight line L extending in the tire radial direction is a straight line connecting the center of rotation of the tire and the lowermost end 1a of the bead core 1 of each carcass code 14b, and the angle formed by this straight line L and the carcass code 14b is an inclination angle. It is set to θ2.

In this way, since the inclination direction of the reinforcement cord 13 is opposite to the inclination direction of the carcass cord 14b with respect to the straight line extending in the tire radial direction, the angle formed by the reinforcement cord 13 and the carcass cord 14b is surely 10 °. The above can be done.

The winding portion 16 extends from the bead core 1 beyond the bead filler 2 to the outer surface of the main body portion 15. The dimension d1 from the tip of the bead filler 2 to the winding end of the winding portion 16 is 10 mm or more. However, the position of the winding end is such that the dimension d2 from the end portion in the tire width direction of the belt located inside in the tire radial direction toward the center side in the tire width direction is up to 20 mm.

The pneumatic tire having the above configuration has the following advantages.

The winding portion 16 of the carcass ply 3 is extended beyond the bead filler 2 so as to be laminated on the outer surface of the main body portion 15. The carcass cord 14 has a different inclination angle between the main body portion 15 and the winding portion 16. Therefore, the carcass cord 14a of the main body portion 15 and the carcass cord 14b of the winding portion 16 intersect with each other, and even though the carcass ply 3 is only one, the carcass cords 14a and 14b interact with each other and the tag is used. Depending on the effect, the rigidity in any of the tire radial direction, the tire circumferential direction, and the tire width direction can be increased. Therefore, it is possible to improve the steering stability performance of the pneumatic tire.

In particular, the position of the winding end of the carcass ply 3 is 10 mm or more from the tip of the bead filler 2. Therefore, it is possible to secure a range in which the carcass cords 14a and 14b intersect and sufficiently increase the rigidity. Further, the position of the winding end of the carcass ply 3 is set to 20 mm from the end portion in the tire width direction of the belt located inside in the tire radial direction toward the center side in the tire width direction. Therefore, the weight does not increase and the fuel efficiency does not deteriorate, and the tire rigidity does not become too high and the riding comfort does not deteriorate.

Further, the angle formed by the reinforcing cord 13 and the carcass cord 14b is set to 10 ° or more. Therefore, the tag effect can be exerted not only between the carcass cords 14a and 14b but also between the reinforcing cord 13 and the carcass cord 14b. This makes it possible to further increase the rigidity and improve the steering stability performance.

For the comparative examples and examples shown in Table 1, pneumatic tires having a size of 285 / 45R20 112Y were mounted on an SUV (Sport Utility Vehicle), and sensory evaluation was performed on steering stability performance and riding comfort performance. The sensory evaluation was expressed as an exponent when the case of the comparative example was set to 100. The larger the index, the better the steering stability performance and the riding comfort performance. Further, the total weight of the tire was evaluated by an index when the case of the comparative example was set to 100. The larger the index, the heavier the weight.
In Comparative Example 1, the carcass cord 14b extends in the same direction as the carcass cord 14a, that is, in the tire radial direction. The position of the winding end of the carcass ply 3 is projected 10 mm from the reinforcing layer 12.
In Comparative Example 2, the carcass cord 14b extends in the tire radial direction as in Comparative Example 1, but the position of the winding end of the carcass ply 3 is 20 mm from the belt end toward the center in the tire width direction. ing.
In the embodiment, the carcass cord 14b is tilted by 60 ° with respect to the carcass cord 14a. The position of the winding end of the carcass ply 3 protrudes from the reinforcing layer 12 by 10 mm.

In this way, even with one carcass ply 3, sufficient rigidity can be obtained due to the tag effect due to the crossed cords, so that the steering stability performance and riding are superior to those of the pneumatic tire of Comparative Example 1. It is possible to demonstrate the comfort performance. Further, unlike the pneumatic tire of Comparative Example 2, the weight does not increase, so that the fuel consumption does not deteriorate.

The present invention is not limited to the configuration described in the above embodiment, and various modifications can be made.

In the above embodiment, the reinforcing layer 12 is configured to extend beyond the bead filler 2 to the outside in the tire radial direction, but may be configured not to exceed the bead filler 2. In this case, the winding portion 16 of the carcass ply 3 may be wound beyond the bead filler 2 to a range of 10 mm or more.

In the above embodiment, the carcass cord 14b at the winding portion 16 of the carcass ply 3 is inclined to the opposite side to the straight line extending in the tire radial direction from the reinforcing cord 13 of the reinforcing layer 12. As shown, it may be tilted to the same side. In this case, the inclination angle θ2 formed by the straight line L extending in the tire radial direction and the reinforcing cord 13 is set in a range of 40 ° or more and 80 ° or less, preferably 60 °. The carcass code 14b is in the range of 10 ° or more and 50 ° or less with respect to the straight line L extending in the tire radial direction, but is set so that there is an angle difference of 10 ° or more between the carcass code 14b and the reinforcing cord 13. Has been done.

Even with this configuration, the rigidity can be increased by the tag effect as in the above embodiment, so that excellent steering stability performance can be exhibited.

1 ... bead core 1a ... bottom edge 2 ... bead filler 3 ... carcass ply 4 ... belt 5 ... reinforcing belt 6 ... tread part 7 ... sidewall part 8 ... rim protector 9 ... bead part 10 ... chafer 11 ... inner liner 12 ... Reinforcing layer 12a ... Bottom end 13 ... Reinforcing cord 14, 14a, 14b ... Carcass cord 15 ... Main body 16 ... Winding part

Claims (4)

Bead cores placed on both sides in the tire width direction,
A bead filler that is connected to the bead core and extends outward in the radial direction of the tire.
A carcass ply, which is made by covering a plurality of juxtaposed cords with a coating layer and hung over the bead core,
The belt wound on the outer side of the carcass ply in the tire radial direction,
A reinforcing layer arranged on the outer side of the bead filler in the tire width direction,
Equipped with
The carcass ply has a main body portion in which the cord extends along the meridian cross section, and a winding portion in which the cord is wound from the bead core to the outer surface side of the tire and the cord extends crossing the cord of the main body portion when viewed from the tire width direction. ,
Equipped with
The winding portion is laminated on the outer surface of the main body portion of the bead filler and the reinforcing layer located on the outer side in the tire radial direction beyond the outer side in the tire radial direction .
The cord of the reinforcing layer is a pneumatic tire that is inclined to the same side as the cord of the winding portion at an angle of 40 ° or more and 80 ° or less with respect to a straight line extending in the radial direction of the tire. The pneumatic tire according to claim 1 , wherein the winding end of the carcass ply is laminated on the outer surface of the main body portion so as to exceed the bead filler by 10 mm or more outward in the radial direction of the tire. The pneumatic tire according to claim 1 or 2 , wherein the winding ends of the carcass ply are located within a range of up to 20 mm toward the center side in the tire width direction with respect to both ends of the belt in the tire width direction. .. The pneumatic tire according to any one of claims 1 to 3 , wherein the angle between the cord of the reinforcing layer and the cord of the winding portion of the carcass ply is 10 ° or more.

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