JP2001187523A - Pneumatic tire - Google Patents

Abstract

PROBLEM TO BE SOLVED: To secure excellent vibrating riding feeling and a reduced in-car noises, and to improve steering stability, without increasing substantially a tire weight and rolling resistance. SOLUTION: This pneumatic tire is equipped with one carcass ply 3 rewound around a bead core 2, and a bead filter 4 arranged between a body part 3a of the carcass ply 3 and a rewound part 3b on the circumferential side of the bead core 2. In the tire, a cord reinforcing layer 7 formed by a cord extended at an angle in the range of 70-110 deg. against a radial line segment is arranged in a region in the radius direction between the bead core 2 and the rewound end of the carcass ply 3 between the body part 3a of the carcass ply 3 and the rewound part 3b, and the inner end in the radius direction of the cord reinforcing layer 7 is positioned close to the body part 3a of the carcass ply 3, and the cord reinforcing layer 7 is drawn gradually close to the rewound part 3b of the carcass ply 3 outward in the radius direction.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a pneumatic tire,
In particular, the present invention relates to improvement of a bead portion of a pneumatic radial tire, and in particular, to effectively improve steering stability while ensuring excellent vibration riding comfort.

[0002]

2. Description of the Related Art Along with the recent improvement of automobile performance, various types of pneumatic tires have various characteristics such as steering stability, vibration riding comfort, vehicle interior noise, and fuel efficiency when mounted on a vehicle. Improvements in performance have been strongly demanded.

[0003] Conventionally, such demands are generally addressed by improving individual performances using a design method that has already been established. For example, improvement in steering stability performance is achieved by cornering. The increase in power, the increase in rigidity due to the addition of a reinforcing layer to the bead portion, the increase in hysteresis loss of tread rubber, etc. It is to be realized by the decline and others.

[0004]

However, when various performances are to be improved in this way, for example, an increase in the bead rigidity for improving the steering stability,
There is an inconvenience of causing a reduction in vibration riding comfort, an increase in vehicle interior noise, and the like, and therefore, it is necessary to adjust other components of the tire, other components of the tire, for example, a rubber thickness of a tread portion, and the like. Therefore, it was necessary to balance these two performances, which are in conflict with each other.

[0005] In addition, such performance harmony is usually performed at the expense of reducing the weight of the tire. However, recently, with increasing interest in environmental issues such as global warming, tires have been developed. It has been desired to achieve a high level of compatibility between steering stability, vibration comfort and vehicle interior noise without sacrificing the weight of the vehicle.

An object of the present invention is to solve such problems of the prior art, and it is an object of the present invention to provide an excellent tire without a substantial increase in tire weight. It is an object of the present invention to provide a pneumatic tire that has improved driving stability while ensuring vibration riding comfort and low vehicle interior noise.

[0007]

By the way, considering the mechanism of transmitting vibration and noise from the pneumatic tire to the vehicle, the vibration input to the rolling tire from the uneven portion of the road surface is first transmitted to the belt. That vibration, and this belt vibration is transmitted to the whole of the tire,
Since the transmission path from the tire bead portion to the rim is followed, in order to improve the riding comfort and reduce vehicle interior noise, the transmission of the vibration input to the belt to the bead portion must be performed. It is effective to hinder the tire side portion by an excellent vibration damping action based on the soft deformation of the tire side portion. Further, in order to improve the steering stability, it is effective to increase the rigidity in the lateral direction, particularly at the tire side portion.

Accordingly, the rigidity of the tire is set low in the vertical direction to provide high vibration riding comfort, while the rigidity of the tire is set high in the lateral direction and the front-back direction to provide excellent steering stability. Performance can be compatible.

Therefore, in the pneumatic tire of the present invention, at least one carcass ply wrapped around a bead core provided in a bead portion, and a carcass ply main body portion and a rewound portion on the outer peripheral side of the bead core. A bead filler disposed between the carcass ply body portion and the rewinding portion, in a radial region between the bead core and the rewind end of the carcass ply, the radial line segment A cord reinforcement layer formed by cords extending at an angle in the range of 70 to 110 ° is provided, and a radially inner end portion of the cord reinforcement layer is provided on either the main body portion or the rewind portion of the carcass ply. The cord reinforcement layer is placed close to the carcass ply, and the cord reinforcement layer is gradually approached to either the winding part or the body part of the carcass ply outward in the radial direction. That.

[0010] In addition, the extension angle of the cord forming the cord reinforcing layer with respect to the radial line segment is set in the range of 70 to 110 °, thereby advantageously suppressing an increase in the rigidity of the tire in the up-down direction, thereby improving the tire side portion. Flexibility can be sufficiently ensured, and as a result, excellent vibration comfort and low vehicle interior noise can be realized, and at the same time, the rolling resistance of the tire can be kept low. In other words,
When the extending direction of the cord of the cord reinforcing layer is out of the above range, the extending direction of the cord is too close to the radial line segment, and the rigidity in the vertical direction of the tire is inevitably increased.

Further, in this tire, the radially inner end portion of the cord reinforcing layer is located close to either the main body portion or the rewind portion of the carcass ply, and the cord reinforcing layer is positioned radially outward. Gradually approaching either the winding portion or the main body of the carcass ply, and gradually increasing or decreasing the distance of the cord reinforcing layer in the tire width direction with respect to the carcass ply main body in the radially outward direction. As a result, the neutral axis intersects with the neutral axis at the time of deformation, and the dependency at the time of load increases.

Here, when the distance between the cord reinforcing layer and the carcass ply body is gradually increased outward in the radial direction, the reinforcing effect under a low load is increased, and the reinforcing effect under a high load is increased. Can be made smaller, and excellent in straight running stability and vibration / ride comfort. Conversely, when the distance is gradually reduced, the reinforcing effect under a high load can be increased, and the reinforcing effect under a low load can be reduced, resulting in excellent steering stability during cornering.

Thus, the pneumatic tire can provide high steering stability while ensuring excellent vibration riding comfort and low vehicle interior noise without increasing tire weight and rolling resistance.

[0014] More preferably, in such a tire, the cord reinforcing layer is formed by 15 mm in the tire radial direction.
It is arranged over the above range. According to this, the steering stability can be further enhanced while the rigidity in the lateral and longitudinal directions of the tire is further increased while maintaining excellent vibration riding comfort and low vehicle interior noise.

[0015] More preferably, the cord reinforcing layer has a spirally wound structure of one or more cords, and preferably, the number of cords in the radial cross section of the cord reinforcing layer is 15 or more. According to the former, the cords of the cord reinforcing layer extend at an angle of about 90 ° with respect to the radial line segment, so that the rigidity of the tire in the vertical direction can be more advantageously suppressed. Here, when the cord reinforcing layer has a spiral wound structure of a plurality of cords arranged in parallel in the radial direction of the tire, for example, the cord reinforcing layer is simply and easily formed in a short time. be able to. In the latter case, the number of cords in the cord reinforcing layer is 15
With more than this, the rigidity of the tire in the lateral direction and the front-back direction can be further increased.

[0016]

Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 is a radial sectional view showing an essential part of an embodiment of the present invention. For example, in this figure showing a tubeless tire having a radial structure, reference numeral 1 denotes a bead portion, and 2 denotes a bead portion. Each shows a bead core, the tire comprising, for example, at least two belt layers in the tread part.

Here, one carcass ply 3 is wrapped around the bead core 2 from the inside to the outside in the tire width direction, and the main body portion 3a of the carcass ply 3 and the rewind portion 3b are wrapped around the bead core 2. The bead filler 4 is disposed between the bead core 2 and a single carcass ply 5 that is terminated without being rewound on the bead core 2 is disposed outside the rewound portion 3b. Reference numeral 6 in the drawing denotes a canvas chafer, which functions to suppress damage to the bead portion due to friction between the rim and the bead portion during rim assembly or running.

In this embodiment, the bead core 2
On the outer peripheral side, the rewind end of the carcass ply 3, in other words, in the region on the inner peripheral side from the radially outer end of the rewind portion 3 b, between the main body portion 3 a and the rewind portion 3 b of the carcass ply 3, 70-110 ° to radial line segment of tire
, More preferably, a cord reinforcing layer 7 composed of cords extending at an angle of about 90 °, and preferably, the disposing range of the cord reinforcing layer 7 is 15 mm or more in the tire radial direction. Also, preferably, the number of cords of the cord reinforcing layer 7 in the illustrated cross section is set to 15 or more.

Here, such a cord reinforcing layer 7 is used.
The radial extension of the carcass ply 3 is such that the inner end in the radial direction is close to the main body 3a of the carcass ply 3 but the carcass ply 3 is turned outward in the radial direction.
And its radially outer end portion extends along the rewind portion 3b for some distance.

FIG. 2 is a radial cross-sectional view of a bead portion conceptually showing a relative relationship between the cord reinforcing layer 7, the bead filler 4 and the bead core 2 thus arranged. More preferably has a spirally wound structure of one or a plurality of cords as shown, and the radially outer end of the cord reinforcing layer 7 is set lower than that of the bead filler 4. As a result, it is possible to improve the steering stability while suppressing vibration / noise and a decrease in ride comfort.

According to the pneumatic tire configured as described above, as described above, the tire weight can be substantially reduced based on the action of the cord reinforcing layer 7 having a unique extension in the tire radial direction. Without any increase in the tires, and therefore without adversely affecting the global environment, excellent vibration riding comfort and low vehicle interior noise are fully ensured, and the steering stability based on the increase in tire lateral rigidity and longitudinal rigidity is improved. An improvement can be realized.

FIG. 3 is a sectional view similar to FIG. 1 showing another embodiment of the present invention. In particular, the radial extension of the cord reinforcing layer 7 in the tire in the radial direction is set such that the radially inner end of the cord reinforcing layer 7 is close to the rewind portion 3b of the carcass ply 3. On the other hand, the carcass ply 3 is to be gradually approached radially outward to the main body 3a, and its radially outer end is extended along the main body 3a for a certain distance. It was made to exist.

[0023]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, tire weights and various types of tires according to the present invention having the illustrated configuration, conventional tires, and comparative tires, when their sizes and structures are shown in Table 1, are shown. Table 2 shows room characteristics such as rigidity and rolling resistance, and actual vehicle feelings regarding steering stability, vibration riding comfort, and vehicle interior noise. The index values in Tables 1 and 2 indicate higher values as the index values increase. In addition, the steering stability and vibration riding comfort during the actual vehicle feeling were evaluated in 10 levels for both plus and minus, the plus side was evaluated as good, and the overall noise level of the vehicle interior noise when the vehicle was actually running was measured. And one side was good.

[0024]

[Table 1]

[0025]

[Table 2]

According to Table 2, particularly in the case of the example tires 1 to 3, the steering comfort is sufficiently secured without substantially increasing the tire weight, the rolling resistance and the vehicle interior noise. It is clear that a useful improvement in stability can be realized.

[0027]

As is apparent from the above description, according to the present invention, particularly, between the bead core and the rewind end of the carcass ply, between the body portion and the rewind portion of the carcass ply. A cord reinforcing layer formed by a cord extending at an angle in the range of 70 to 110 ° with respect to the radial line segment is provided in the radial direction region, and the radial extension of the cord reinforcing layer is specified. As a result, it is possible to effectively improve steering stability while ensuring excellent vibration riding comfort and low vehicle interior noise without substantially increasing tire weight and rolling resistance.

[Brief description of the drawings]

FIG. 1 is a radial cross-sectional view showing an essential part of an embodiment of the present invention.

FIG. 2 is a radial cross-sectional view of a bead portion, conceptually showing a relative relationship between a cord reinforcing layer, a bead filler, and a bead portion.

FIG. 3 is a view similar to FIG. 1, showing another embodiment of the present invention.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Bead part 2 Bead core 3, 5 Carcass ply 3a Main part 3b Rewinding part 4 Bead filler 6 Canvas chafer 7 Cord reinforcement layer

Claims (4)

[Claims] At least one carcass ply wound around a bead core provided on a bead portion, and a bead filler disposed between a main body portion of the carcass ply and a wound portion on an outer peripheral side of the bead core. A pneumatic tire comprising: between a body portion and a rewind portion of the carcass ply, in a radial region between a bead core and a rewind end of the carcass ply, having an angle of 70 to 110 ° with respect to a radial line segment. A cord reinforcing layer formed by cords extending at a range of angles is provided, and a radially inner end portion of the cord reinforcing layer is positioned close to either the main body portion or the rewind portion of the carcass ply. A pneumatic tire in which the cord reinforcing layer is gradually approached to either the wound portion or the main body portion of the carcass ply outward in the radial direction. 2. A cord reinforcing layer having a thickness of 15 mm in the tire radial direction.
The pneumatic tire according to claim 1, wherein the pneumatic tire is disposed over a range of not less than mm. 3. The cord reinforcing layer according to claim 1, wherein the cord reinforcing layer has a spiral wound structure of one or a plurality of cords.
A pneumatic tire according to claim 1. 4. The pneumatic tire according to claim 1, wherein the number of cords in the radial cross section of the cord reinforcing layer is 15 or more.