JP2000001105A - Radial tire - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a radial tire that can decrease road noise. SOLUTION: Two belt layers 7 comprises two belt plies 7A, 7B that are lapped in the radial direction of the tire. At the outer end portion of the belt layers 7, a band layer 9 in which organic fiber cords are aligned in substantially parallel along the circumferential direction of the tire is provided. The band layer 9 is formed by a hold band ply 10 to wrap the outer end of the inner belt ply 7A and a non-hold band play 11 arranged along the outer surface of the outer belt ply 7B.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a radial tire capable of reducing road noise.

[0002]

2. Description of the Related Art In recent years, there has been a strong demand for a quiet vehicle.
There is an urgent need to reduce road noise on the high frequency side of 400 Hz. As a method of reducing this road noise, it is effective to soften the tread rubber of the radial tire, but in exchange for this, there is a problem that steering stability and abrasion resistance are greatly impaired, so it is not suitable for practical use. Absent.

[0003] In recent years, it has been found that such road noise can be reduced by increasing the rigidity of the outer end portion in the tire axial direction of a belt layer for loosely tightening a carcass of a radial tire. For example, FIG.
As shown in (a), a so-called band layer c1 in which organic fiber cords are arranged substantially parallel to the tire circumferential direction is provided outside the belt layer b in the tire radial direction.
309805, and the like.

[0004] Further, as shown in FIG.
A so-called hold band c2 which wraps together the outer ends of the two belt plies b1 and b2 in the tire axial direction to form a substantially U-shape and two hold band plies c3 which individually wrap each belt ply b1 and b2 , C4 is proposed in, for example, Japanese Patent Application Laid-Open No. 4-290733.

[0005]

However, FIG.
In the band structure shown in (a) and (b), the effect of increasing the rigidity of the outer end portion of the belt layer b in the tire axial direction is not yet sufficient, and the road noise reduction effect is small and further improvement is required.

In FIG. 1C, two layers of band plies are interposed between the inner and outer belt plies b1 and b2, so that the inner and outer belt plies b1 and b2 are provided.
However, the outer end portion is largely separated in the tire radial direction. Thus, the inner and outer belt plies b1, b2
When there is a separation at the outer end portion, there is a tendency that the cornering force generated during turning or the like tends to decrease, and there is a problem that steering stability during turning and running is reduced.

The present invention has been devised in view of the above-described problems. A belt layer is provided at the outer end of the belt layer in the tire axial direction, and the band layer wraps the inner belt ply. Basically, it consists of one hold band ply and one non-hold band ply that covers the outer belt ply. The rigidity of the outer end of the belt layer in the tire axial direction is effectively increased to improve steering stability. It is intended to provide a radial tire that can reduce road noise while improving durability.

[0008]

The first object of the present invention is as follows.
The described invention is based on a radially structured carcass extending from the tread portion to the bead core of the bead portion via the sidewall portion, and two belt plies arranged radially outside the carcass and inside and outside the tread portion in the tire radial direction. And a belt layer provided with organic fiber cords substantially arranged in parallel in the tire circumferential direction at the outer end of the belt layer in the tire axial direction. The inner belt ply along the inner surface of the inner belt ply in the tire radial direction, and the outer end of the inner belt ply being continuous with the inner band ply and extending between the inner and outer belt plies. A hold band ply wrapping the outer end of the inner belt ply with the band piece; and a non-hole disposed along the outer surface of the outer belt ply. It is characterized in that it consists of band ply.

According to a second aspect of the present invention, the band layer is formed by spirally winding a band-like ply rubber-coated with one organic fiber cord or a cord parallel body in which a small number of organic fiber cords are arranged in parallel. The width W1 of the inner band piece is 0.1 to 0.5 of the width BW1 of the inner belt ply in the tire axial direction.
And the width W2 of the inner band piece is 0.05 to 0.2 times the width BW1 of the inner belt ply, and the width W3 of the non-hold band ply is the tire shaft of the outer belt ply. The radial tire according to claim 1, wherein the width is 0.1 to 0.5 times the width BW2 in the direction.

[0010]

An embodiment of the present invention will be described below with reference to the drawings. The radial tire of the present embodiment is:
As shown in FIG. 1, the tread portion 2 to the sidewall portion 3
And a carcass 6 which is folded back around the bead core 5 of the bead portion 4 and locked therethrough, and two belt plies arranged radially outside of the carcass 6 and inside and outside of the tread portion 2 in the tire radial direction. Belt layer 7 composed of 7A and 7B
Illustrates a radial tire for passenger cars equipped with
The left section appears symmetrically with the right section.

The carcass 6 comprises, for example, one or more carcass plies 6A having a radial structure in which carcass cords are arranged at an angle of 75 ° to 90 ° with respect to the tire equator C, in this embodiment. As the carcass cord, an organic fiber cord such as nylon, rayon, or polyester is used in the present embodiment, but a steel cord may be used if necessary and further depending on the type of tire.

The carcass 6 passes through the bead core 5 of the bead portion 4 from the tread portion 2 through the sidewall portion 3.
A bead apex 8 made of hard rubber is disposed between the main body 6a and the folded portion 6b extending from the main body 6a and being turned around the bead core 5. Reinforced.

The belt layer 7 is formed over substantially the entire area of the tread portion 2. For example, a steel cord is arranged at a small angle of 10 to 45 ° with respect to the tire equator.
The two outer belt plies 7A and 7B are overlapped in a direction in which the cords cross each other. The width BW1 of the inner belt ply 7A in the tire axial direction is formed wider than the width BW2 of the outer belt ply 7B, but may be reversed. However, if the two belt plies 7A and 7B have the same width, the bending stiffness in the cross section changes suddenly at the ends thereof, which adversely affects durability. Therefore, the two belts are set to at least different widths. Is preferred.

At the outer end of the belt layer 7 in the tire axial direction, as shown in FIGS. 1 and 2, a band layer 9 in which organic fiber cords are arranged substantially in the tire circumferential direction is provided. Provided. In addition, "substantially along the tire circumferential direction"
"Includes those inclined at an angle of 5 degrees or less with respect to the tire circumferential direction." The “outer end of the belt layer 7” includes at least a range of at least 10 mm inward in the tire axial direction from the outer end of the belt layer 7.

In the present embodiment, the band layer 9 is formed by spirally winding a band-like ply 14 in which one organic fiber cord 13 is covered with a topping rubber G as shown in FIG. As shown in FIG. 4, a belt-like ply 15 in which a cord parallel body in which a small number of organic fiber cords 13 are arranged in parallel is coated with rubber can be used. At this time, the number of codes arranged in parallel is preferably 15 or less, more preferably 10 or less, and further preferably 5 or less.

In this embodiment, a nylon cord is used as the organic fiber cord of the band layer 9.
Various organic fiber materials such as spun yarns of organic fibers made of aromatic polyamide or the like, monofilament yarns, multifilament single yarns, and fuel yarns are included.

The band layer 9 is continuous with the inner band piece 10a along the inner surface of the inner belt ply 7A in the tire radial direction, and is connected to the inner band piece 10a at the outer end of the inner belt ply 7A. Hold band ply 10 wrapping the outer end of the inner belt ply with band piece 10b extending between inner and outer belt plies 7A and 7B, and along the outer surface of outer belt ply 7B The non-hold band ply 11 is provided.

As described above, by disposing the hold band ply 10 for the inner belt ply 7A and the non-hold band ply 11 that does not enclose the belt ply 7B for the outer belt ply 7b, The rigidity of the outer end can be effectively increased, the durability can be increased, and road noise, especially road noise on the high frequency side can be significantly reduced. Further, since the non-hold band ply 11 is used for the outer belt ply 7B, it is possible to prevent the inner and outer belt plies 7A and 7B from being largely separated in the tire radial direction at the outer ends thereof.
Therefore, a decrease in cornering force at the time of turning can be suppressed.

Preferably, the outer belt ply 7B
It is preferable that the distance between the belt cords in the tire radial direction at the outer end is less than 1.0 mm.

Here, the hold band ply 10
Is the width W1 of the inner band piece 10a as shown in FIG.
Is 0.1 to 0.5 of the width BW1 of the inner belt ply 7A.
Times, preferably 0.1 to 0.3 times, more preferably 0.1 times.
Desirably, it is 1 to 0.2 times. Band piece 1
If the width W1 of 0a is less than 0.1 times the width BW1 of the inner belt ply 7A, the rigidity of the belt layer 7 cannot be increased,
Conversely, if it exceeds 0.5 times, the rigidity of the belt layer may be unnecessarily increased, and the riding comfort may be impaired.

The width W2 of the band piece 10b is as follows.
The width BW1 of the belt ply 7A is 0.05 to 0.
Preferably, it is twice as large, and more preferably smaller than the inner band piece 10a. Thereby, the inner band piece 1
A rigidity step caused by the overlap of the inner end of the outer band piece 10b with the outer band piece 10a can be prevented, and the durability is improved.

Further, the non-hold band ply 11
The width W3 of the outer belt ply 7B is 0.1 to 0.5 times, more preferably 0.1 to 0.3 times the width BW2 of the outer belt ply 7B,
More preferably, it is desirably 0.1 to 0.2 times.

Such a band layer is, for example, shown in FIG.
As shown in (A), first, the band-like ply 14 made of an organic fiber cord is spirally wound at a small lead angle on a cylindrical drum 17 capable of expanding and contracting, and the inner band piece 10 is formed.
a is formed. At this time, in order to ensure the symmetry of the tire, it is preferable that the tires are wound from the inside to the outside in the tire axial direction.

Next, as shown in FIG. 1B, the inner belt ply 7A is wound on the inner band piece 10a, and the belt ply 14 is further spirally wound on the drum at a small lead angle. To form a middle band piece 10b. At this time, in order to ensure the symmetry of the tire, it is preferable to wind the tire from the outside to the inside in the axial direction of the tire. After that, the winding machine that winds the belt-like ply 13 on the drum is fed in an idling manner. To move it outward in the tire axial direction (indicated by a dashed line). Thereby, the hold band ply 10 is formed. At this time, the outer end of the inner belt ply 7A is terminated within a range not exceeding the outer end of the inner band piece 10a. Therefore, the above band piece 10
a is formed by exposing from the outer end of the inner belt ply 7A outward in the tire axial direction and continuously winding the inner band piece 10b in a spiral and inward in the tire axial direction. sell.

Next, as shown in FIG. 2C, the outer belt ply 7B is wound on the inner band piece 10a, and the band ply 14 is further spirally wound on the drum at a small lead angle. The non-hold band ply 11 can be formed by winding and terminating.

As shown in FIGS. 5A to 5C, by forming the band layer 9 using the band-like ply 14 (or 15), the seam of the band layer 9 is eliminated, and the uniformity of the tire is improved. At the same time, the binding force on the belt layer 7 is increased, and the high-speed durability can be further improved. Although not shown, as the hold band ply 10 and the non-hold ply 11, a normal ply in the form of a sheet can be used in addition to a spiral wrap of such a band ply.

[0027]

EXAMPLES Radial tires having a tire size of 195 / 60R15 and shown in Table 1 were prototyped (Examples, Comparative Examples 1 to 4, conventional examples), and road noise, passing noise, steering stability, and high-speed durability were obtained. Were tested for performance comparison. BW1 = 152 mm and BW2 = 142 mm.

The test conditions are as follows. <Road noise> A 2000cc Japanese passenger car is equipped with four test tires and travels 50km / m on a smooth road surface.
h, the driver's seat left ear, and the overall noise level dB at the ear level at the center of the rear seat
(A) was measured and indicated by an index with Comparative Example 1 being 100. The higher the value, the lower the noise level and the better.

<Passing noise> In accordance with the actual vehicle coasting test specified in JASO / C / 606, the vehicle was caused to coast on a straight test course (asphalt road surface) at a passing speed of 60 km / h for a distance of 50 m, At a midpoint, 7.5 m laterally from the running center line and 1.2 from the road surface
The maximum level dB (A) of the passing noise was measured by a stationary microphone installed at the position of m. The results are shown in Comparative Example 1.
Is set to 100 and the passing noise is smaller and better as the index is larger.

<Steering stability> On a dry asphalt road surface of a tire test course, steering response, rigidity,
In addition to the grip, high-speed turning characteristics are particularly emphasized, and the index is set to 100 with Comparative Example 1 as a sensory evaluation by the driver. The larger the index, the better.

<High-Speed Durability> A high-speed durability test (Camber angle = 0 °, 4 °) based on the conditions of ECE30 was performed. The higher the value, the better. Table 1 shows the test results and the like.

[0032]

[Table 1]

As a result of the test, it was confirmed that the tire of the example reduced road noise and the like while improving durability and steering stability. In the case shown in FIG. 6C, it was also confirmed that the steering stability was lowered.

[0034]

As described above, in the radial tire of the present invention, the hold belt ply is disposed for the inner belt ply, and the non-hold band ply is disposed for the outer belt ply, thereby forming the belt layer. The rigidity of the outer end can be effectively increased, the durability can be increased, and road noise, especially road noise on the high frequency side can be significantly reduced. Also, in the outer belt ply,
The use of a non-hold band ply prevents the inner and outer belt plies from being greatly separated in the tire radial direction at their outer ends, thereby suppressing a decrease in cornering force during cornering and improving steering stability. Can be maintained.

[Brief description of the drawings]

FIG. 1 is a sectional view of a tire showing an embodiment of the present invention.

FIG. 2 is an enlarged sectional view showing an outer end portion of a belt layer.

FIG. 3 is a perspective view showing an example of a belt-like ply.

FIG. 4 is a perspective view showing another example of the belt-like ply.

FIGS. 5A to 5C are schematic cross-sectional views illustrating a method for forming a band layer.

FIGS. 6A to 6D are cross-sectional views of a band layer for explaining a conventional technique and the like.

[Explanation of symbols]

 2 Tread part 3 Side wall part 4 Bead part 5 Bead core 6 Carcass 6A Carcass ply 7 Belt ply inside belt layer 7A Belt ply outside 9B 9 Band layer 10 Hold band ply 10A Band piece inside 10b Band piece 11 Inside non-hold Band ply

Claims (2)

[Claims] A carcass having a radial structure extending from a tread portion to a bead core of a bead portion through a sidewall portion;
A radial layer having two belt plies disposed radially inward of the carcass and radially inward and outward of the tread portion inward of the tread portion; And a band layer in which organic fiber cords are substantially arranged in parallel along the tire circumferential direction. The band layer includes an inner band piece along the tire radial direction inner surface of the inner belt ply, and an inner belt. A hold band ply wrapping around the outer end of the inner belt ply with an inner end of the inner ply by a band piece extending from the inner and outer belt plies at the outer end of the ply and extending between the inner and outer belt plies; and A radial tire comprising a non-hold band ply disposed along an outer surface of a belt ply. 2. The band layer is formed by spirally winding a band-like ply rubber-coated with one organic fiber cord or a cord parallel body in which a small number of organic fiber cords are arranged in parallel. Is the width W of the above band piece.
1 is the width BW1 of the inner belt ply in the tire axial direction.
The width W2 of the inner band piece is 0.05 to 0.2 times the width BW1 of the inner belt ply, and the width W3 of the non-hold band ply is outside. The radial tire according to claim 1, wherein the width is 0.1 to 0.5 times the width BW2 of the belt ply in the tire axial direction.