JP2011136658A - Pneumatic tire - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a pneumatic tire which enhances the cutting resistance and the abrasion resistance, reduces its mass, and enhances the high-speed durability performance. <P>SOLUTION: The tire axial end 20E of a belt ply 20 of the maximum width out of a main belt layer 16 is located on the inner side of the tire radial direction from the tire equatorial plane position 20C of the belt ply 20. Further, in the tire axial section, the relationship between the radius of curvature of a carcass layer 14 and the radius of curvature of the main belt layer 16 in an area 26 of the tire axial end of the main belt layer 16 is set so that the radius of curvature of the carcass layer is smaller than the radius of curvature of the main belt layer 16. <P>COPYRIGHT: (C)2011,JPO&INPIT

Description

  The present invention relates to a pneumatic tire, and particularly to a pneumatic tire having high cut resistance and wear resistance, light weight, and high speed durability.

  Examples of the performance required for pneumatic tires, particularly aircraft radial tires include cut resistance and wear resistance. In order to improve these two performances, it has hitherto been known that it is effective to suppress the tire diameter growth during filling with internal pressure.

  On the other hand, from the economical and environmental viewpoints, reducing the aircraft mass is a proposition for aircraft manufacturers, and the demand for mass reduction from tire manufacturers is rapidly increasing.

  In order to satisfy the above-described requirements, it has become a national challenge to deal with the conventional technology, and the development of tires using a new technology has been demanded.

  Therefore, in order to suppress the tire diameter growth during filling with internal pressure, organic fiber cords having a higher elastic modulus, such as aromatics, are used instead of fibers having a relatively high elastic modulus, such as cords of aliphatic polyamide, which have been the mainstream in conventional products. A tire in which a group polyamide is applied to a belt reinforcing layer has been proposed (see Patent Document 1).

International Publication No. 03/061991

  Using a high-strength cord as described above, and a so-called angled belt layer in which the cord has an angle with respect to the tire circumferential direction, the cord angle with respect to the tire equatorial plane being approximately 0 ° Thus, it is possible to suppress the diameter growth at the time of filling with the internal pressure more than before by winding in a spiral shape in the tire circumferential direction.

  Furthermore, by reducing the thickness distribution of the belt layer gradually from the tire center (tire equatorial plane) toward the end of the belt layer in the axial direction of the tire (belt end), high cut resistance and abrasion resistance are achieved. The weight of the tire can be reduced while maintaining wear.

  However, in the tire having the structure described above, there is one aspect that the belt tension of the tire shoulder portion is lower than the belt tension of the tire center portion, and it is difficult to maintain high-speed durability performance.

  In view of the above facts, an object of the present invention is to improve cut resistance and wear resistance of a pneumatic tire, reduce mass, and improve high-speed durability performance.

  The invention of claim 1 includes at least a pair of bead cores, a carcass layer including at least one carcass ply extending in a toroidal shape from one bead core to the other bead core, and an outer side in the tire radial direction of the carcass layer. A main belt layer comprising at least one belt ply including a cord spirally wound in the tire circumferential direction, and provided on the outer side in the tire radial direction of the main belt layer, A sub-belt layer including a cord disposed to be inclined with respect to the tire circumferential direction, and a tire axial direction end of the belt ply having the maximum width of the main belt layer, It is located on the inner side in the tire radial direction from the tire equatorial plane position of the belt ply, and in the tire axial cross section, the end of the main belt layer in the tire axial direction The relationship between the radius of curvature of the main belt layer and the radius of curvature of the carcass layer in the region, a carcass layer of curvature radius <main belt layer curvature.

  Here, the region of the main belt layer at the tire axial direction end is 0.1 B inward from the tire axial direction end to the tire axial direction, assuming that the distance from the tire equatorial plane to the tire axial direction end of the main belt layer is B. The range up to.

  In the pneumatic tire according to claim 1, the pneumatic tire includes at least one belt ply including a cord in which a cord is spirally wound in the tire circumferential direction on the outer peripheral surface of the crown region on the outer side in the tire radial direction of the carcass layer. By providing a main belt layer, and providing a sub belt layer including a cord inclined with respect to the tire circumferential direction on the outer side in the tire radial direction of the main belt layer, the radial growth of the pneumatic tire during internal pressure filling is suppressed, Excellent cut resistance and wear resistance can be obtained.

  Further, the end of the main belt layer in the tire axial direction of the belt ply having the maximum width is disposed on the inner side in the tire radial direction from the position of the tire equatorial plane of the belt ply. Since the relationship between the radius of curvature of the carcass layer and the radius of curvature of the main belt layer in the end region is appropriately set, the rigidity distribution of the belt layer with respect to the internal pressure is optimized, and necessary members can be minimized. For this reason, about a pneumatic tire, it becomes possible to improve high-speed durability performance, reducing mass.

  According to a second aspect of the present invention, in the pneumatic tire according to the first aspect, when the tire axial dimension of the belt ply having the maximum width in the main belt layer is 2B, the tire axial direction is 0.9B from the tire equatorial plane. To B, a rubber layer is provided between the main belt layer and the carcass layer, and the thickness of the rubber layer at a position of 0.9B in the tire axial direction from the tire equator plane is T1, and the tire equator When the thickness of the rubber layer at the position B in the tire axial direction from the surface is T2, the relationship between T1 and T2 is 0.07 <T1 / T2 <0.2.

  In the pneumatic tire according to claim 2, the rubber layer thickness T1, T2 in the region of the end of the main belt layer in the tire axial direction is appropriately set so that the thickness of the rubber layer is greater than that of the conventional product. The case line at the tire shoulder is lowered inward in the tire radial direction. As a result, the burden ratio of the tire internal pressure of the main belt layer at the tire shoulder increases. For this reason, it is possible to increase the tension of the main belt layer in the tire shoulder portion, and it is possible to further improve the high-speed durability performance.

  As described above, according to the pneumatic tire according to claim 1 of the present invention, it is possible to improve cut resistance and wear resistance, reduce mass, and increase high-speed durability performance. Excellent effect is obtained.

  According to the pneumatic tire of the second aspect, it is possible to obtain an excellent effect that the high-speed durability performance can be further improved.

It is sectional drawing which shows a pneumatic tire.

  Hereinafter, embodiments for carrying out the present invention will be described with reference to the drawings. In FIG. 1, a pneumatic tire 10 according to the present embodiment is a pneumatic radial tire for aircraft, for example, and includes at least a pair of bead cores 12, a carcass layer 14, a main belt layer 16, and a sub belt layer 18. And have.

  The carcass layer 14 is composed of at least one or more carcass plies (not shown) extending in a toroid shape from one bead core 12 toward the other bead core (not shown).

  The main belt layer 16 is provided on the outer circumferential surface of the crown region on the outer side in the tire radial direction of the carcass layer 14 and includes at least one belt ply including a cord (not shown) wound spirally in the tire circumferential direction. For example, it consists of two belt plies 20 and 22.

  The tire axial direction end 20E of the belt ply 20 having the maximum width in the main belt layer 16 is located on the inner side in the tire radial direction from the tire equatorial plane position 20C of the belt ply 20. Further, in the tire axial section, the relationship between the radius of curvature of the carcass layer 14 and the radius of curvature of the main belt layer 16 in the region 26 at the tire axial direction end of the main belt layer 16 is: It is.

  Here, the region 26 at the tire axial direction end of the main belt layer 16 refers to the tire axial direction end 20E from the tire axial direction end 20E when the distance from the tire equatorial plane CL to the tire axial direction end 20E of the main belt layer 16 is B. The range up to 0.1B on the inner side in the direction.

  Further, the thickness of the main belt layer 16 gradually decreases from the tire equatorial plane CL toward the tire axial end 20E. Specifically, when the thickness of the main belt layer 16 at the position of the tire equatorial plane CL is G0, and the thickness of the main belt layer 16 at a position of 0.8B in the tire axial direction from the tire equatorial plane CL is G1. G1 / G0 <0. Thereby, since the rigidity distribution of the belt layer with respect to the internal pressure is optimized, the necessary members can be minimized and the mass of the pneumatic tire 10 can be reduced. More preferably, 0.2 ≦ G1 / G0 ≦ 0.8. This is because the mass can be further reduced.

  The pneumatic tire 10 has a main belt layer 16 in the range from 0.9B to B in the tire axial direction from the tire equatorial plane CL, where the tire axial dimension of the belt ply 20 having the maximum width in the main belt layer 16 is 2B. And a rubber layer 24 between the carcass layer 14. When the thickness of the rubber layer 24 at a position 0.9B from the tire equatorial plane CL in the tire axial direction is T1, and the thickness of the rubber layer 24 at the position B from the tire equatorial plane CL in the tire axial direction is T2. The relationship between T1 and T2 is 0.07 <T1 / T2 <0.2.

  Here, the reason why T1 / T2 is set larger than 0.07 is to secure the belt tension in the tire shoulder portion. The reason why T1 / T2 is made smaller than 0.2 is to prevent weight increase.

  The sub belt layer 18 is provided on the outer side in the tire radial direction of the main belt layer 16 and includes a cord (not shown) arranged to be inclined with respect to the tire circumferential direction. This cord is made of, for example, an organic fiber, and the inclination angle with respect to the tire circumferential direction is, for example, 2 to 45 °. When the inclination angle of the cord is less than 2 °, the rigidity of the sub belt layer 18 increases, and a rigidity step is generated between the sub belt layer 18 and the tread 28, and a failure occurs at the interface. Since it becomes easy to do, it is not preferable. On the other hand, when the inclination angle of the cord exceeds 45 °, the rigidity step between the main belt layer 16 and the sub belt layer 18 is similarly increased, and a failure at the interface is likely to occur. The tread 28 is a grounding portion to a road surface (not shown) provided on the outer side in the tire radial direction of the sub belt layer 18.

  A tire axial direction end 18E of the auxiliary belt layer 18 is, for example, a position of 0.8B in the tire axial direction from the tire equatorial plane CL. This is because, if the tire axial direction end 18E of the sub belt layer 18 is located at, for example, a shoulder groove inside the tire equatorial plane CL in the tire axial direction from 0.8B, there is a possibility that it becomes a starting point of failure. . Also, if the tire axial direction end 18E of the sub belt layer 18 is outside 0.8B in the tire axial direction from the tire equatorial plane CL, it may be a factor of early withdrawal of the pneumatic tire 10.

(Function)
This embodiment is configured as described above, and the operation thereof will be described below. In FIG. 1, in the pneumatic tire 10 according to the present embodiment, at least one belt including a cord spirally wound in the tire circumferential direction on the outer circumferential surface of the crown region of the carcass layer 14 in the tire radial direction. The main belt layer 16 composed of the plies 20 and 22 is provided, and the auxiliary belt layer 18 including a cord inclined with respect to the tire circumferential direction is provided on the outer side in the tire radial direction of the main belt layer 16, thereby The diameter growth of the entering tire 10 can be suppressed, and excellent cut resistance and wear resistance can be obtained.

  Further, the tire belt axial end 20E of the belt ply 20 having the maximum width in the main belt layer 16 is disposed on the inner side in the tire radial direction with respect to the tire equatorial plane position 20C of the belt ply 20. Since the relationship between the radius of curvature of the carcass layer 14 and the radius of curvature of the main belt layer 16 in the region 26 at the tire axial direction end of the layer 16 is appropriately set, the rigidity distribution of the main belt layer 16 with respect to the internal pressure is optimized. The necessary members can be minimized. For this reason, it is possible to improve the high-speed durability performance of the pneumatic tire 10 while reducing the mass.

  Furthermore, in the pneumatic tire 10, the thickness of the rubber layer 24 is set to be greater than that of the conventional product by appropriately setting the relationship between the thicknesses T1 and T2 of the rubber layer 24 in the region 26 in the tire axial direction end of the main belt layer 16. The case line at the tire shoulder is lowered inward in the tire radial direction. Thereby, the burden ratio of the tire internal pressure of the main belt layer 16 in the tire shoulder portion is increased. For this reason, it becomes possible to increase the tension of the main belt layer 16 in the tire shoulder portion, and it is possible to further improve the high-speed durability performance.

(Test example)
Using the pneumatic tires for aircraft manufactured under the conditions shown in Table 1, applying a normal internal pressure to each, taking off 150% of the normal load and performing T / O (take-off), standing wave The speed at which was generated was measured. The tire size is 1400 × 530R23 40PR. Here, “normal load” and “normal internal pressure” refer to the maximum load and the air pressure with respect to the maximum load in the application size / ply rating defined in Aircraft Year Book 2008.

  The test results are as shown in Table 1. In Table 1, the standing wave generation speed is indicated by an index with the conventional example being 100. The larger the value, the better the high-speed durability. According to Table 1, the standing wave generation speed according to each example is 5% higher in Example 1, 10% in Example 2, and 15% in Example 3 than in the conventional example. Therefore, it turns out that the pneumatic tire which concerns on each Example is excellent in high-speed durability compared with a prior art example.

DESCRIPTION OF SYMBOLS 10 Tire 12 Bead core 14 Carcass layer 16 Main belt layer 18 Sub belt layer 20 Belt ply 20C Tire equatorial plane position 20E Tire axial direction edge 24 Rubber layer 26 Area | region of tire axial direction edge of main belt layer CL Tire equatorial plane

Claims (2)

At least a pair of bead cores;
A carcass layer comprising at least one or more carcass plies extending in a toroidal shape from one bead core to the other bead core;
A main belt layer comprising at least one belt ply including a cord spirally wound in the tire circumferential direction, provided on the outer circumferential surface of the crown region on the outer side in the tire radial direction of the carcass layer;
A sub-belt layer including a cord provided on the outer side in the tire radial direction of the main belt layer and arranged to be inclined with respect to the tire circumferential direction, and a pneumatic tire comprising:
The tire axial direction end of the belt ply of the maximum width of the main belt layer is located on the inner side in the tire radial direction from the tire equatorial plane position of the belt ply,
In the tire axial section, the relationship between the radius of curvature of the carcass layer and the radius of curvature of the main belt layer in the region of the tire belt direction end of the main belt layer,
Pneumatic tire with carcass layer radius of curvature <main belt layer radius of curvature. When the tire axial direction dimension of the maximum width of the belt ply in the main belt layer is 2B,
In the range from 0.9B to B in the tire axial direction from the tire equatorial plane, a rubber layer is provided between the main belt layer and the carcass layer,
When the thickness of the rubber layer at a position of 0.9B in the tire axial direction from the tire equator plane is T1, and the thickness of the rubber layer at the position B in the tire axial direction from the tire equator plane is T2, T1 And the relationship between T2
0.07 <T1 / T2 <0.2
The pneumatic tire according to claim 1.

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