JPH08216630A - Tire used for vehicle - Google Patents

Abstract

PURPOSE: To improve the performance of a tire used for a vehicle resisting against pinch puncture by arranging a shock absorbing material of a specific repulsive modulus of elasticity on a side wall part with which at least the flange of a rim makes contact, continuously or discontinuously, in the circumferential direction of the tire. CONSTITUTION: A shock absorbing material 8 continuing in the circumferential direction of a tire 1 is provided on a side wall part 3 with which the flange part 7 of a rim 5 makes contact from a bead part 4, and this material 8 is brought in contact with the flange part 7. Also the shock absorbing material 8 is pasted on the tire 1 before vulcanization of the tire 1 and stuck thereto by vulcanization of the tire 1 so-called vulcanizing connection. Such a mterial as having its repulsive modulus of elasticity less than 0.5% is used as the shock absorbing material 8. The lower this repulsive modulus of elasticity is, the better the shock absorbing property is, and then urethane foam, NR sponge, etc., for example, used therefor. As a result, when the tire runs on a step on a road surface or any obstacle, the shock is absorbed so as to prevent pinch puncture. When the tire runs on a mud land, etc., in its state of a low inner pressure, any clearance between fitting portions of side wall part 3 and the rim 5 is blocked so as to prevent mud, etc., from invading therein.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a vehicle tire having improved pinch puncture resistance.

[0002]

2. Description of the Related Art In the past, punctures in vehicle tires have been mostly caused by the penetration of foreign matter on the road surface. However, in recent years, as roads have been paved and roads and sidewalks have been separated, penetration puncture of foreign substances has decreased, but on the other hand, a collision when riding on a step on the road surface caused the tires to flex instantaneously and the flanges of the rims to fall. There is a problem of pinch puncture that occurs when the tube is sandwiched between the tip of the section and the obstacle on the road surface together with the sidewall section.

The lower the air pressure of a tire, the greater the deflection under load, and the greater the deformation at the time of collision. Therefore, most of the pinch punctures can be prevented by controlling the tire air pressure and using it at standard air pressure. And, of course, when the tire for a vehicle is mounted, air having a standard pressure or higher is filled. However, since the user's interest in air pressure management is low, even if the tires are in a low air pressure due to a gradual decrease in air pressure after a long period of use, the bicycle is still used as is. .

Therefore, it is important to improve the pinch puncture resistance from the tire side. It has been conventionally known that the pinch puncture can be prevented by increasing the rigidity of the sidewall portion of the tire to reduce the deformation of the tire at the time of collision. For example, by increasing the thickness of rubber from the bead portion to the sidewall portion or increasing the number of tire cords to be driven, the rigidity of the portion can be increased.

[0005]

However, in view of the running performance of the tire, when the tire is provided with extra meat,
This not only causes problems such as an increase in rolling resistance and a reduction in cushioning properties, but also causes an increase in the weight of the vehicle body.
In recent years, there has been great interest in reducing the weight of vehicles,
There is a strong demand that the performance will remain the same and that it will be as light as possible.

The present invention has been made to solve the above problems, and an object thereof is to provide a vehicle tire having improved pinch puncture resistance without impairing running performance.

[0007]

In order to achieve the above object, a vehicle tire according to the present invention has a sidewall portion of a tire, which is in contact with at least a flange portion of a rim, continuous or non-continuous in the circumferential direction of the tire. Rebound resilience is 5% continuously
The following shock absorbers are arranged.

[0008]

According to the present invention, with the above structure, when the tire and the tube are momentarily bent by riding on a step or an obstacle on the road surface, the stress from the flange portion is buffered by the shock absorbing material having excellent shock absorbing property. , It prevents the transmission of stress to the tube and prevents pinch puncture.

[0009]

An embodiment of the present invention will be described below with reference to the drawings. 1 and 2, a vehicle tire 1 includes a tread portion 2 in contact with the ground, left and right sidewall portions 3, and right and left bead portions 4 which are connected to each other, and a bead portion 4 and a rim 5 are fitted to each other. The air pressure of the tube 6 in the tire 1 supports the vehicle body. The impact absorbing material 8 continuous in the circumferential direction of the tire 1 is attached to the sidewall portion 3 where the bead portion 4 contacts the flange portion 7 of the rim 5.
Is provided. The area where the shock absorbing material 8 is provided is the bead portion 4
It is a region from the side wall part 3 to the side wall part 3, and it is not necessary to cover the bead part 4 or the side wall part 3 entirely. The impact absorbing material 8 is in contact with the flange portion 7, but may be formed so as to contact the flange portion only when an impact is applied to the tire 1.

The shock absorbing material 8 may be directly attached to the side wall portion 3 and the bead portion 4 as shown in FIG. 3, but via the bead chafer 9 for protecting the bead portion 4 as shown in FIG. It may be attached, or the impact absorbing material 8 may be attached to two bead chafers by sandwiching them, as shown in FIG. Needless to say, when the shock absorber 8 is arranged together with the bead chafer 9, the shock absorption is further improved. The bead chafer 9 is made of cloth or the like. Further, the shock absorbing material 8 is bonded before the tire 1 is vulcanized, and so-called vulcanization bonding is performed so that the tire 1 is adhered by vulcanization. Therefore, the vulcanization of the tire results in the adhesion at the same time. Of course, other joining methods may be used. According to the present embodiment, the cross section of the impact absorbing material 8 before being attached to the tire 1 is 8 mm × 1.5 mm.
However, this may be appropriately designed according to the application. Further, the cross-sectional shape can be arbitrarily designed by thickening only the portion in contact with the flange portion 7.

Next, the shock absorber 8 will be described. The impact absorbing material 8 has a impact resilience of 0.5% in this embodiment.
I'm using one. Here, the impact resilience is JIS
According to the K6301 test method, a steel ball is dropped onto a test piece from a certain height, the height of repulsion is measured, and the height is expressed as a ratio. That is, the lower the impact resilience, the better the impact absorption. The repulsion elastic modulus of a typical material is, for example, 42.8 for urethane foam and 47. for NR sponge.
The impact absorbing material 8 used in this example has a repulsion elastic modulus that is considerably lower than that of a normal material, and is excellent in impact absorbing property.

Moreover, the impact absorbing material 8 of this embodiment is lightweight because of its foamed structure, and the increase in the weight of the tire can be suppressed to a minimum. In addition, in the present embodiment, the one having a repulsion elastic modulus of 0.5% was used, but if it is 5% or less, it can be said that the pinch puncture resistance is very excellent.

Next, the operation of the above configuration will be described.
When the conventional tire 11 shown in FIG. 6 rides on a step or an obstacle on a road surface in a state of low internal pressure, the sidewall portion 13 bends and is sandwiched between the flange portion 17 and the obstacle on the road surface, and 16 is damaged. When this degree is large, there is a hole in the tube 16 and pinch puncture occurs.

However, in the tire 1 of the present embodiment shown in FIGS. 1 and 2, the impact absorbing material 8 formed from the bead portion 4 to the side wall portion 3 is the flange when the collision is caused by riding on a step or an obstacle on the road surface. It is possible to prevent the pinch puncture by abutting against the portion 7 to receive the flange portion 7 and absorb the shock at the time of the collision from the flange portion 7 by the characteristics of the impact absorbing material 8.

Further, according to the tire of this embodiment, the following problems can be solved. When traveling on a road surface such as a sandy or a mud in a state where the air pressure is low, the fitting performance between the rim 15 and the tire 11 deteriorates with a decrease in the air pressure as shown in FIG. Foreign matter 18 such as dirt or mud may invade and damage the tube 16 or the like.

However, in the tire 1 of this embodiment shown in FIG. 1 and FIG. 2, the sidewall portion 3 and the flange portion 7 of the rim 5 are separated from each other when the road surface runs on sand or mud in a low internal pressure state. The gap created in the fitting portion is always closed by the expansion and contraction of the shock absorbing material 8, so that the entry of sand, mud, etc. can be prevented.

Next, a comparative test of the pinch puncture resistance performance and the rim fitting performance of the vehicle tire according to the present invention and the conventional example will be described. In this test, the following two test samples were performed. Tires are for bicycles. The results are shown in (Table 1).

(Embodiment 1) A bicycle tire according to this embodiment. The size is 26 × 2.10 according to the JIS standard display. The size is the same below.

(Comparative Test Example 1) A conventional bicycle tire having the same construction as that of this embodiment except that it does not have a shock absorbing material.

The comparative test method for the pinch puncture resistance performance is to set the tire air pressure to 1.0 kgf / cm ² and attach it to the test apparatus shown in FIG. 7, and let it fall naturally on the L-shaped angle A of 40 mm × 40 mm. . From the position of the initial angle θ,
The angle was increased by 2.5 ° and the test was repeated until pinch puncture occurred. When the pinch puncture occurred, the angle was recorded, the test was terminated, and the energy at the time of collision, that is, the kinetic energy E was calculated according to the following equation.

[0021]

[Equation 1]

[0022]

[Table 1]

From the above results, since the vehicle tire of the present invention is remarkably effective in preventing the pinch puncture at low internal pressure, the conventional vehicle tire (Comparative Test Example 1).
It can be said that it is much better in pinch puncture resistance compared to.

The test method for comparing the fitting performance with the rim is as follows:
After setting a test tire to an air pressure of 1.0 kgf / cm ² on a predetermined course of a swamp having a depth of about 5 cm, the tire was mounted on a bicycle and actually run at 20 km / h for 10 minutes. After the lapse of 10 minutes, the state inside the test tire is confirmed and compared.

[0025]

[Table 2]

From the above results, the vehicle tire of the present invention has a remarkable effect on the prevention of intrusion of sand or mud when traveling on a road surface such as sand or mud in a low internal pressure state. It can be said that the tire has significantly better fit performance with the rim than the conventional vehicle tire (Comparative Test Example 1).

Further, even if the shock absorber 8 is not provided on the entire circumference, the effect is not so much deteriorated even if the shock absorber 8 has a discontinuous shape such as a 4-division or 6-division shape with respect to the circumference.

Further, the shock absorbing material 8 can be provided at a position different from that of the above embodiment. The tire 1 has the tread portion 2, sidewall portions 3 on both sides, and bead portions 4 on both sides formed by bending the carcass layer 10 and disposing a tread rubber in the center. Therefore, it is possible to provide a shock absorbing material between the carcass layer 10 and the tread rubber. Further, it may be provided between the layer carcass layer 10 below the tread portion 2 and the tube 6.
Also in this case, the pinch puncture resistance is improved, and further, it has an effect of preventing the penetration of foreign matters such as nails.

The present invention describes and tests a bicycle tire as an example of a vehicle tire.
It can also be applied to other vehicles such as motorcycles.

[0030]

As described above, according to the present invention, it is possible to provide a vehicle tire excellent in pinch puncture resistance by disposing the impact absorbing material.

[Brief description of drawings]

FIG. 1 is a sectional view of a vehicle tire according to an embodiment of the present invention.

FIG. 2 is a side view of a vehicle tire according to an embodiment of the present invention.

FIG. 3 is an enlarged cross-sectional view around a shock absorbing material of a vehicle tire of the present invention.

FIG. 4 is an enlarged cross-sectional view around a shock absorbing material of a vehicle tire of the present invention.

FIG. 5 is an enlarged cross-sectional view of the vicinity of the impact absorbing material of the vehicle tire of the present invention.

FIG. 6 is a sectional view of a conventional vehicle tire.

FIG. 7 is a diagram showing a test method of anti-pinch puncture performance.

FIG. 8 is a diagram illustrating the fit performance of a conventional vehicle tire.

[Explanation of symbols]

 1 Tire 3 Sidewall Part 4 Bead Part 5 Rim 6 Tube 7 Flange Part 8 Impact Absorber 10 Carcass Layer

Claims (6)

[Claims] 1. A vehicle for which a shock absorbing material having a rebound resilience of 5% or less is arranged continuously or discontinuously in a circumferential direction of the tire on a sidewall portion of a tire with which at least a flange portion of the rim abuts. tire. 2. Between the carcass layer of the tire and the tread rubber, or between the carcass layer of the tire and the tube,
A vehicle tire provided with an impact absorbing material having a rebound resilience of 5% or less. 3. The vehicle tire according to claim 1, wherein a shock absorbing material is arranged in a region extending from the bead portion to the sidewall portion of the tire. 4. The vehicle tire according to claim 1, wherein the shock absorbing material is provided via a bead chafer that protects a bead portion of the tire. 5. The vehicle tire according to claim 1, wherein the impact absorbing material is disposed between two bead chafers. 6. The vehicle tire according to claim 1, wherein the shock absorbing material is adhered at the same time as vulcanization of the tire.