JP2007055559A - Tire charging gas and gas charging tire rim assembly - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a tire charging gas and a gas charged tire rim assembly filled with the gas in which an inner pressure reduction (gas leakage) of the tire assembly can be remarkably restricted as compared with that of the conventional art. <P>SOLUTION: A two-inert-gas mixture gas consists of argon gas and nitrogen gas, a volumetric ratio of the mixture gas is in a specified range where a gas leakage ratio becomes lower than a leakage ratio of nitrogen itself and preferably it contains argon gas of 2.5 to 10 vol.%. In addition, there is provided a gas charged tire rim assembly in which argon gas and nitrogen gas are filled in an inner space of the tire rim assembly having a tubeless tire 1 installed at its corresponding rim 6 and a volumetric ratio of the mixture gas shows a specified range where a gas leakage ratio becomes lower than a leakage ratio of nitrogen itself and preferably the two-inert-gas mixture gas containing argon gas of 2.5 to 10 vol.% is filled. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a tire filling gas for filling a tire of a self-propelled device such as a vehicle such as a passenger car, a truck, a racing car, and an aircraft, and also for the above-mentioned tire filling to achieve long-term stabilization of the tire internal pressure. The present invention relates to a gas-filled tire / rim assembly formed by filling gas.

  Air is traditionally used as a tire filling gas, but recently it is used not only for special tires such as racing cars and aircraft that are forced to drive at high speeds and severely, but also for general tires such as passenger cars. It has been proposed to fill a gas other than air (see, for example, Patent Document 1 and Patent Document 2).

  The tire filling gas described in Patent Document 1 is an inert two-type mixed gas composed of helium gas and nitrogen gas, and contains 20 to 45 vol% helium gas. This is a tire rubber which is a fatal defect as a tire filling gas while ensuring the superiority peculiar to helium gas, that is, that the heat conductivity is higher than that of nitrogen gas and the specific heat is extremely low. It is intended to eliminate as much as possible the very high permeability to the layer.

Further, the tire filling gas described in Patent Document 2 is obtained by substituting a part of a gas containing carbon atoms and fluorine atoms in the molecule with argon or nitrogen. This is intended to suppress a decrease in internal pressure of the tire assembly by filling a gas having low permeability to the tire rubber layer. Further, in paragraph “0023” of Patent Document 2, “Argon has a molecular weight larger than that of nitrogen or oxygen, and therefore, as a gas filled in the tire / rim assembly from the viewpoint of reducing permeation / permeation into rubber” Is preferred. "
JP 2002-046583 A (in particular, claims). JP 2003-291606 A (particularly claims).

  Although the tire filling gas described in Patent Documents 1 and 2 (hereinafter referred to as the prior art) is superior to the conventional one, it is still insufficient in terms of suppressing a decrease in internal pressure of the tire assembly. Moreover, the description of paragraph “0023” in Patent Document 2 is based on misidentification, and it has been confirmed by experiments conducted by the present inventors that the gas leakage rate of the argon gas alone is larger than that of air ( (See Table 1). Accordingly, the present invention has been made in view of such circumstances, and the object thereof is to provide a tire filling gas and a gas that can significantly suppress a decrease in internal pressure (gas leakage) of the tire assembly as compared with the prior art. It is an object to provide a gas-filled tire / rim assembly filled with a gas.

  The present invention has been made as a result of intensive studies to solve the above problems, and is based on the following findings. The inventor is an inert two-type mixed gas composed of argon gas and nitrogen gas, and in a specific volume ratio range, the gas leakage rate is smaller than that of air alone or nitrogen gas alone. I came to find it.

That is, the tire filling gas according to claim 1 is an inert two-type mixed gas composed of argon gas and nitrogen gas, and the volume ratio of the mixed gas is such that the gas leakage rate is a leakage rate of nitrogen alone. It is characterized by being a specific range smaller than.

Further, the tire filling gas according to claim 2 is characterized in that the specific volume ratio contains 2.5 to 10 vol% argon gas with respect to the tire filling gas according to claim 1. .

  Further, according to a third aspect of the present invention, there is provided a gas-filled tire / rim assembly, wherein an argon gas and a nitrogen gas are provided in an internal space portion of the tire / rim assembly formed by mounting the tubeless tire 1 on the corresponding rim 6. An inert two-type mixed gas comprising the above is filled, and the volume ratio of the two-type mixed gas is in a specific range in which the gas leakage rate is smaller than the leakage rate of nitrogen alone.

Furthermore, the gas-filled tire / rim assembly according to claim 4 is the same as the gas-filled tire / rim assembly according to claim 3, wherein the mixed gas has a volume ratio of 2.5 to 10 vol% argon gas. It is characterized by containing.

  In the present invention, an inert two-type mixed gas composed of argon gas and nitrogen gas, a specific volume ratio range of the mixed gas, that is, a specific range in which the gas leakage rate is smaller than the leakage rate of nitrogen alone. More preferably, a gas for filling tires containing 2.5 to 10 vol% of argon gas, and a gas-filled tire / rim assembly formed by filling the gas for filling tires, Only when such an inert two-type mixed gas is used, the gas leakage rate is extremely small as compared with the case of air alone or nitrogen gas alone. Thereby, the internal pressure fall (gas leak) of a tire assembly can be suppressed markedly rather than a prior art.

  Thereby, this invention has the following outstanding practical effects. That is, (a) along with the internal pressure long-term stable holding action of the inert two-type mixed gas, it leads to stable running and fuel efficiency improvement of self-propelled devices such as vehicles and aircrafts. (B) The inert two-type mixed gas itself contributes to prevention of corrosion, oxidation, deterioration, etc. of the rim.

  Hereinafter, the gas-filled tire / rim assembly and the tire filling gas according to the present invention will be described in detail with reference to the drawings. FIG. 2 is a sectional view in the tire width direction of the tire / rim assembly according to the embodiment of the present invention. The illustrated tire / rim assembly is formed by mounting a hollow donut-shaped tubeless tire 1 on a corresponding rim 6, and an inner space portion of the assembly formed by the tubeless tire 1 and the corresponding rim 6 is described later. Inactive two-type mixed gas is filled.

  The tubeless tire 1 has an outer layer portion 2 and an inner liner layer 3 made of rubber or the like adhered to the entire inner surface of the outer layer portion 2. The outer layer portion 2 includes a bead portion 21 for causing the corresponding rim 6 to be bitten, a tread portion 22 that is in contact with the ground, and a sidewall portion 23 that is a region between the bead portion 21 and the tread portion 22. . A carcass 24 for maintaining the shape of the tubeless tire 1 is provided inside the bead portion 21, the tread portion 22, and the sidewall portion 23. A plurality of belt layers 25 for adjusting the rigidity of the tread portion 22 are provided between the tread portion 22 and the carcass 24. Reference numeral 26 denotes a rim valve.

  The above-mentioned two kinds of mixed gas filled in the tire / rim assembly having the above-described structure is an inert gas composed of argon gas and nitrogen gas. In addition, it is already known that nitrogen gas alone has a lower permeability to rubber than air, and the present inventors have a higher permeability to rubber of argon gas alone than air. (See Table 2).

  Based on this knowledge, by conducting various experiments on the mixing ratio of argon gas and nitrogen gas in the mixed gas to be filled, comparing with normal air while taking into consideration the advantages and disadvantages in practical and economic aspects. The inventors have found suitable conditions from the test results described in the following examples.

  First, in a constant temperature room, the volume ratio of the mixed gas of argon gas and nitrogen gas in the mixed gas to be filled, that is, the argon concentration is changed from 0 to 100%, and the change in tire pressure (leakage rate) is measured by the laboratory test. Measured under correction. The results are as shown in Table 1 below.

  A graph showing the dynamics of the leakage rate based on the test results in Table 1 is shown in FIG. The change in the leakage rate is observed with reference to Table 1 and FIG. When the leak rate when only air is filled is 100, and the argon gas concentration (%, in nitrogen gas) is changed by filling a mixed gas of argon gas and nitrogen gas, the air in a specific volume ratio range In spite of containing argon gas, which has a higher leak rate than nitrogen and nitrogen, the leak rate was found to be smaller than that of nitrogen alone. That is, the mixed gas according to the present invention effectively functions as a tire filling gas within a specific volume ratio range in which the gas leakage rate is smaller than the leakage rate of nitrogen alone.

  As shown in Table 1 and FIG. 1, the specific volume ratio range refers to a range where the argon concentration exceeds zero and is approximately 31%. In this range, the gas leakage rate is smaller than that of nitrogen alone. More specifically, when the argon concentration (%, in nitrogen gas) is 5%, the leakage rate is 34 and the leakage rate is minimum, and in the range of several percent (2.5 to 10%) before and after the leakage rate, the leakage rate is extremely small. Turned out to be.

Based on the above results, the specific volume ratio of the mixed gas of argon gas and nitrogen gas in the mixed gas to be filled, that is, the leakage rate is higher than that of nitrogen gas alone in the range where the argon concentration exceeds zero and is approximately 31%. It was found that the leakage rate was much smaller than that of nitrogen gas alone in the range of 2.5 to 10%, where the argon concentration was around 5%. Thus, it is clear that the inert two-mixed gas composed of argon gas and nitrogen gas having a specific volume ratio contributes sufficiently to the improvement of the internal pressure retention for the tire / rim assembly.

  By the way, when filling the tire / rim assembly with a mixed gas of argon gas and nitrogen gas, it is necessary to reduce the ratio of air (especially oxygen) inevitably remaining in the tire / rim assembly as much as possible. Therefore, it is desirable to carry out the process of once filling the mixed gas and then removing the gas once and filling the mixed gas again once or more. That is, air that inevitably remains in the tire / rim assembly as a practical problem does not correspond to “filling” in the present invention. Accordingly, even if a minute amount of air or the like that is not intended for filling remains in the tire / rim assembly, it is not excluded from the technical scope of the present invention.

  Subsequently, the permeability | transmittance by the rubber sheet of nitrogen gas single, argon gas single, and the mixed gas of nitrogen gas and argon gas was measured. The results are as shown in Table 2 below. However, the permeability is a test with a rubber sheet and cannot be directly converted into an air leak rate with a tire, but shows a qualitative tendency.

  According to Table 2, it is clear that the permeability to the rubber sheet is lower in the mixed gas (nitrogen 95% + argon 5%) than in the case of nitrogen alone. This indicates that the rubber permeability of the mixed gas is affected by the mixing ratio of the gas, and is considered to be due to the difference in solubility between nitrogen and argon. The qualitative tendency is consistent with a decrease in leakage rate at a specific volume ratio of the mixed gas.

  As described above, the present invention has been described based on the tire / rim assembly. However, the inert two-type mixed gas according to the present invention is not limited to a tire or the like, but is, for example, a rubber hollow column-shaped fender used at a harbor pier. It is also suitably used as a filling gas for objects.

It is a figure which shows a gas leak test result. It is a tire width direction sectional view of a tire rim assembly concerning an embodiment of the present invention.

Explanation of symbols

1 ... Tubeless tire, 6 ... Corresponding rim.

Claims (4)

  An inert two-type mixed gas composed of argon gas and nitrogen gas, wherein the volume ratio of the mixed gas is a specific range in which the gas leakage rate is smaller than the leakage rate of nitrogen alone. Tire filling gas.   The tire filling gas according to claim 1, wherein the specific volume ratio contains 2.5 to 10 vol% of argon gas. The inner space portion of the tire / rim assembly formed by mounting the tubeless tire (1) on the corresponding rim (6) is filled with an inert two-type mixed gas composed of argon gas and nitrogen gas. A gas-filled tire / rim assembly characterized in that the volume ratio of the seed mixed gas is in a specific range in which the gas leakage rate is smaller than the leakage rate of nitrogen alone. 4. The gas-filled tire / rim assembly according to claim 3, wherein the volume ratio of the mixed gas contains 2.5 to 10 vol% of argon gas.