JPH08230421A - Pneumatic tire and air charging method for pneumatic tire - Google Patents

Abstract

PURPOSE: To provide a pneumatic tire, in which air leakage is reduced and durability is improved, and an air charging method for the pneumatic tire, by which the inside of the tire is turned into an inert, gas environment. CONSTITUTION: An oxygen adsorbent 20 is sealed in a hollow 10 in a tire which is assembled with a rim. Assembly with the rim is carried out after the oxygen adsorbent 20 is inserted in the tire, and then, air is charged in the tire assembled with the rim until an internal pressure in an initial charging time is increased above the using internal pressure.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a pneumatic tire capable of reducing air leakage and improving durability, and a method for filling air in a pneumatic tire.

[0002]

2. Description of the Related Art In conventional pneumatic tires, the internal pressure of the tire is secured by filling air into the tire. Generally, when inert gas such as nitrogen gas or helium gas is filled instead of air. It is well known that compared with the case of filling with air, the filling gas is less likely to leak and the decrease in tire internal pressure can be suppressed.

When the inert gas is filled in this way, air leakage can be reduced, and heat generation is suppressed by securing internal pressure, wear and breakage are improved, and durability is improved. Are known. However, for example, when filling the tire with nitrogen gas,
Generally, filling is performed from a nitrogen gas cylinder through a valve attached to the tire, but the filling method using this valve has a problem that it is difficult to check the filling rate into the tire due to its operation, and filling the tire with nitrogen gas In order to increase the rate, it is necessary to repeat filling and discharging many times, which causes a problem that the work becomes extremely complicated.

In addition, the method of filling with nitrogen gas requires a large-scale device such as a dedicated reservoir tank or pipe for temporarily storing nitrogen gas.
The general user has a problem that the nitrogen gas cannot be easily filled anywhere.

[0005]

SUMMARY OF THE INVENTION An object of the present invention is to convert the air filled in a tire into an inert gas containing nitrogen gas as a main component so that the inside of the tire becomes an inert gas atmosphere. Accordingly, it is an object of the present invention to provide a pneumatic tire capable of reducing air leakage and improving durability, and an air filling method for a pneumatic tire that creates an inert gas atmosphere in the tire.

[0006]

In order to achieve the above-mentioned object, the pneumatic tire of the present invention is characterized in that an oxygen absorbent is enclosed in a tire inner cavity assembled with a rim.
In addition, the method for filling air of the pneumatic tire of the present invention is such that an oxygen absorbent is put into the tire to be assembled on a rim, and the tire assembled on the rim is filled with air so as to have a larger internal pressure at initial filling than the internal pressure used. It is characterized by

Since the oxygen absorbent is enclosed in the inner cavity of the tire as described above, oxygen in the air filled in the tire is absorbed by the oxygen absorbent. Becomes an inert gas atmosphere mainly composed of nitrogen gas. Hereinafter, the configuration of the present invention will be described in detail with reference to the drawings. 1 (a) to 1 (e) are tire meridian direction sectional views showing an example of the pneumatic tire of the present invention, FIG.
1 is a perspective view of the oxygen absorbent holding mechanism (belt) used in FIG. 1D, FIG. 3 is a perspective view of the wheel in FIG. 1D,
4A to 4D are perspective views showing variations of the band fixing mechanism in FIG.

1 (a) to 1 (e), the pneumatic tire of the present invention has a tread portion T, both sidewall portions S connected to the tread portion T, a bead portion B, and a rim assembly to the bead portion B. The inner cavity 10 by the rim R
And the oxygen absorbent is enclosed in the tire cavity 10. The oxygen absorbent used in the present invention is not particularly limited as long as it is a compound capable of absorbing oxygen gas, but among them, iron oxide-based oxygen absorbents, particularly active ferrous oxide are effective. Examples of this oxygen absorber include "Ageless" Z-PK2000 manufactured by Mitsubishi Gas Chemical Company. In addition, an oxygen absorbent such as a hydrazine-based or sodium sulfite-based oxygen absorbent, ferrosilicon, ferromanganese, silicon manganese, aluminum, copper ammonia, or pyrogallol to which an alkaline substance is added may be used.

In FIG. 1A, the tire inner cavity 10 is shown.
The powdery oxygen absorber 20 is directly enclosed therein. In this embodiment, it is of course possible to directly encapsulate a granular or pellet-shaped or tablet-shaped oxygen absorbent in the tire inner cavity 10 instead of the powdered oxygen absorbent. In FIG. 1 (b), a powdery, granular or pellet-shaped oxygen absorbent 20 is formed into a paper or film bag 30 having minute holes 31 to the extent that the oxygen absorbent 20 does not scatter or flow out. And is enclosed in the tire inner cavity 10. In this case, the bag-like material 30
At an appropriate location in the tire cavity 10, for example, the tread portion T
It may be adhesively fixed to the inner surface of the rim or the inner surface of the rim R using an adhesive or an adhesive tape. According to the embodiment of FIG. 1 (b), compared with the embodiment of FIG. 1 (a), for example, when the tire rim is assembled or when the tire is disassembled, the oxygen absorbent 20
Can be prevented from scattering around and contaminating the work environment, and the workability can be improved.

Further, in FIG. 1C, a sheet 40 obtained by molding a composition in which the above oxygen absorbent is mixed with rubber or resin is directly attached to the inner cavity 10 of the tire, the rim R or the inner surface of the tire. It is attached and enclosed, and in this case, an adhesive or an adhesive tape may be used if necessary. Seat 40
For example, as shown in FIG. 2, a notch hole 51 into which a cut product of the sheet 40 can be inserted is provided in the belt 50 as a holding mechanism that can be wound around the outer periphery of the rim R, and the sheet is provided in the notch hole 51. 40 belts are inserted and this belt 5
0 in the tire R by wrapping 0 around the rim R
It can be fixed within 0.

The powdery, granular or pelletized oxygen absorber 20, the bag-like material 30 containing these oxygen absorbers 20 and the sheet 40 containing the oxygen absorber are fixed in the tire inner cavity 10 by, for example, a tire. Appropriate locations in the inner cavity 10, such as the tread portion T and the sidewall portion S
Also, it is possible to store them in a holding mechanism such as a pocket provided on each inner surface of the rim R or a holding chamber.

Further, in FIGS. 1D and 3, a band 60 obtained by molding a composition in which an oxygen absorbent is mixed with a rubber or a resin is used as a rim of a wheel W positioned in the tire inner cavity 10. It is wound around and fixed to the outer peripheral surface of R. The fixing mechanism of the band 60 in this case is shown in FIG.
Various variations shown in (a) to (d) can be adopted. In FIG. 4A, one end of the band 60 is provided with a vertically rotatable fixing portion 61, and the other end is provided with a plurality of grooves 62 in the width direction of the band 60. The fixing portion 61 and the groove 62 are engaged with each other by the band 6
I am trying to fix 0. In FIG. 4B, a fixing portion 61 that is rotatable in the vertical direction is provided at one end of the band 60, and the other end of the band 60 is pressed by the rotation of the fixing portion 61 so that the band 60 is fixed. ing. Figure 4 (c)
Then, a hook-shaped fixing portion 61 is provided at one end of the band 60,
A plurality of holes 63 are formed at the other end, and one of the holes 63 is hooked on the fixing portion 61 to fix the band 60. In FIG. 4D, a fixing portion 61 having an opening in the longitudinal direction of the band 60 is provided at one end of the band 60, and the other end of the band 60 is fitted into this opening to fix the band 60. I have to.

In FIG. 1 (e), a part of the rim R other than the rim flange on which the tire is sealed is provided with one or more holes, and a plug-like fixing is provided with an oxygen absorbent at the tip of the base part. A tool 70 (the base portion of which has a screw-like shape in FIG. 1E) is inserted into the hole and fixed to the rim R. This makes it possible to easily replace and fix the oxygen absorbent without removing the tire when refilling air such as when repairing a flat tire.

Further, a paste obtained by mixing an oxygen absorbent with resin or rubber may be applied to the rim inside the tire inner cavity 10 or the tire inner surface. As a result, the movement of the oxygen absorbent in the tire can be prevented, and the work environment can be prevented from being contaminated due to the scattering of the oxygen absorbent during tire rim assembly and tire disassembly. As described above, the oxygen absorbent 20 is sealed in the tire cavity 10 in advance, and this tire is simply filled with air in the same manner as in the prior art, so that the amount of oxygen in the tire can be reduced easily and reliably. , And can be replaced with an inert gas mainly composed of nitrogen gas.

In this case, the amount of the oxygen absorbent 20 enclosed in the inner cavity 10 of the tire is 5 when the durability of the tire is taken into consideration.
It is desirable that the amount is not more than%. Next, a method for filling air into the pneumatic tire of the present invention will be described. That is, when filling air into a pneumatic tire containing an oxygen absorbent in advance, the volume of the tire inner cavity, the internal pressure used (specified internal pressure for each vehicle type, or the internal pressure set for the purpose of use such as high-speed running) ), By calculating and controlling the internal pressure at the time of filling, the amount of oxygen absorbent enclosed and the amount of oxygen absorbed by this oxygen absorbent so that the tire internal pressure after the oxygen is absorbed by the oxygen absorbent becomes the working internal pressure. The internal pressure at the time of initial filling may be set higher, and preferably 15% or more of the internal pressure used. This makes it possible to easily and surely grasp the oxygen amount and the nitrogen amount in the tire cavity.

For example, the inner volume of the inner cavity of the tire is 24.5.
Initial filling when a bag-shaped oxygen absorbent having an oxygen absorption amount (absorption capacity) of 2 liters is previously charged into the tire inner cavity when filling air having a working internal pressure of 200 kPa into a liter tire. The hourly pressure is derived as follows. First, for example, oxygen existing in the tire inner cavity at an internal pressure of 200 kPa is 24.5 × 3/5 = 14.7.
It is a liter. Therefore, if eight oxygen absorbents are enclosed in the tire cavity, 2 liters x 8 = 16
It becomes liter, and the amount of oxygen in the tire cavity becomes zero.

When all the oxygen present in the air at a rate of 1/5 is absorbed, the set internal pressure drops by about 20%. Therefore, the internal pressure during initial filling is approximately 25% lower than the internal pressure used.
By setting a high value, namely 250 kPa,
The internal pressure after all the oxygen in the tire cavity is absorbed,
It can be the same as the predetermined internal pressure. When four oxygen absorbers are set to 227 kPa, 1/2 of oxygen is absorbed. Note that the time until the amount of oxygen in the tire inner cavity reaches the desired set value after the tire is filled with the calculated air pressure at the initial filling time differs slightly depending on the oxygen absorption capacity of the oxygen absorbent used. However, the equilibrium is usually reached within a few hours or a few days, and thereafter the internal pressure for use can be maintained well.

As described above, according to the present invention, since the oxygen amount and the nitrogen amount in the tire inner cavity can be easily and surely grasped, the workability is improved as compared with the conventional inert gas filling method. Excellent and does not require large-scale equipment. Moreover, since the pneumatic tire filled with air as described above has a low oxygen content in the tire cavity and is replaced with an inert gas containing nitrogen gas as a main component, it has less gas leakage and has a good internal pressure. Since it is possible to maintain the internal pressure of the tire and to secure the internal pressure for use, wear and breakage due to heat generation inside the tire are improved, so that the durability of the tire can be significantly improved.

[0019]

[Example] Tire size: 185 / 65R14, rim used: 14 x 51 / 2JJ, inner pressure used: 200 kPa in the tire inner cavity, an oxygen absorbent having an oxygen absorption capacity of 1 liter (Mitsubishi Gas Chemical Co., Ltd.) A tire of the present invention, which was previously filled with eight "Ageless" Z-PK2000), was filled with air having an internal pressure of 250 kPa at the time of initial filling.

This tire was left at room temperature, 72
After the lapse of time, a working internal pressure of 200 kPa could be secured, and the oxygen content in the tire cavity was zero at this time. On the other hand, for comparison, a conventional tire to which no oxygen absorber was added was filled with air having an initial filling pressure of 200 kPa. When the time-dependent change of the tire internal pressure was measured for these two types of air-filled tires, the tire of the present invention showed significantly less air leakage than the conventional tire as shown in Table 1.

After being left for 100 days, conventional tires were filled with air, adjusted to the same internal pressure as that of the tire of the present invention, and each tire was subjected to a running test under the following conditions. The tire of the present invention was also excellent in the index evaluation (the index of the conventional tire is 100, and the larger the index is, the better). Running test conditions : Each tire was run under the following conditions until it was destroyed, and durability was evaluated by an index of speed at the time of destruction.

Drum diameter: 1700 mm. Load: 4.12KN. Pneumatic pressure: Adjusts the internal pressure of the conventional tire to the internal pressure of the tire of the present invention. Rim: 14 × 5 1 / 2JJ. Speed: Start from 120 km / h, increase the speed by 10 km / h after running for 24 hours, and then run. Thereafter, the speed is increased by 10 km / h every 24 hours.

[0023]

[Table 1] Note) Air pressure measurement conditions Ambient temperature is constant at 21 ° C. The measured air pressure is converted to the air pressure at atmospheric pressure of 1000 kPa for comparison. (Because the atmospheric pressure changes depending on the day)

[0024]

As described above in detail, the pneumatic tire of the present invention can easily and reliably reduce the amount of oxygen in the tire and replace it with an inert gas mainly containing nitrogen gas. As a result, air leakage can be reduced and durability can be improved. Further, according to the pneumatic tire air filling method of the present invention, it is possible to easily and surely grasp the oxygen amount and the nitrogen amount in the tire, so that the workability is improved as compared with the conventional inert gas filling method. However, it does not require large-scale equipment.

[Brief description of drawings]

1 (a) to 1 (e) are tire meridian direction sectional views showing an example of a pneumatic tire of the present invention.

FIG. 2 is a perspective view of an example of an oxygen absorbent holding mechanism.

FIG. 3 is a perspective view of a wheel holding an oxygen absorbent.

FIG. 4A to FIG. 4D are perspective views showing variations of the fixing mechanism of the oxygen absorbent.

[Explanation of symbols]

 10 Tire Inner Cavity 20 Oxygen Absorber 30 Oxygen Absorber-Containing Bag 31 Micropore 40 Sheet 50 Belt (Holding Mechanism) 60 Oxygen Absorber-Containing Belt

Claims (4)

[Claims] 1. A pneumatic tire in which an oxygen absorbent is enclosed in a rim-assembled tire inner cavity. 2. The pneumatic tire according to claim 1, wherein the oxygen absorbent is active ferrous oxide. 3. An air filling method for a pneumatic tire, wherein an oxygen absorbent is placed in a tire, the tire is assembled to a rim, and the tire to which the rim is assembled is filled with air so as to have a larger internal pressure at initial filling than a working internal pressure. 4. The pneumatic filling method for a pneumatic tire according to claim 3, wherein the oxygen absorbent is active ferrous oxide.