JP5753369B2 - Pneumatic tire and rim assembly and motorcycle equipped with the same - Google Patents

Description

  The present invention relates to an assembly of a pneumatic tire and a rim with improved rolling resistance performance while maintaining grip properties, and a motorcycle equipped with the same.

  Regarding the fuel efficiency performance of a vehicle, the influence of tire rolling resistance is large, and the contribution rate is considered to be about 10%. Therefore, in order to reduce the fuel consumption of the vehicle, it is necessary to reduce the rolling resistance of the tire.

  Therefore, conventionally, in order to reduce the rolling resistance of the tire, it has been proposed to employ a rubber having a small loss tangent (tan δ) for the tread rubber (see, for example, Patent Document 1). However, a rubber having a small loss tangent (tan δ) has a problem that the hysteresis loss is reduced by that amount, and the rolling frictional force is reduced. Particularly in recent years, reduction of rolling resistance is also desired for motorcycle tires. However, since motorcycles are unstable vehicles as is well known, the above-mentioned deterioration in gripping property may cause a risk of falling. There is. Therefore, in motorcycle tires, it is difficult to employ rubber having a particularly small loss tangent (tan δ), making it difficult to improve rolling resistance performance.

JP 09-150610 A

  Therefore, the present invention is based on the use of a high-humidity gas as a filling gas in the tire lumen, and an assembly of a pneumatic tire and a rim with improved rolling resistance performance while maintaining grip, and The purpose is to provide a fitted motorcycle.

In order to solve the above-mentioned problems, the invention of claim 1 of the present application fills a tire lumen surrounded by a rim and a pneumatic tire attached to the rim with a filling gas at a filling pressure of 200 to 300 kPa. With
The filling gas, in a state before filling, the filling of the high moisture material relative humidity forms 60% or more and 90.7% or less, while warming so as not to Royui at a temperature 60 ° C. under 1 atm It is characterized by being filled up to a pressure .

  The invention according to claim 2 is characterized in that the relative humidity of the filling gas is 75% or more.

According to a third aspect of the present invention, the filling gas is characterized in that a gas component other than water vapor is nitrogen gas.

According to a fourth aspect of the present invention, there is provided a motorcycle, wherein the pneumatic tire and rim assembly according to any one of the first to third aspects is mounted.

As described above, in the present invention, the filling gas filled in the tire lumen is a high humidity gas having a relative humidity of 60% or more at a temperature of 60 ° C. under 1 atm.

  Although the temperature of the tire rises to some extent by traveling, the tire temperature during traveling is kept substantially constant because it is cooled by cooling by external air or heat conduction. However, when a high-humidity gas is used as the filling gas, the heat capacity of the filling gas is increased by the water vapor contained therein, so that the heat storage effect is enhanced. Therefore, the running tire temperature can be maintained higher than in the conventional case.

  On the other hand, as shown in FIG. 3, the loss tangent (tan δ) of rubber has temperature dependence, and the loss tangent (tan δ) tends to decrease as the temperature increases. Therefore, in the pneumatic tire and rim assembly of the present invention, the loss tangent (tan δ) is substantially reduced by maintaining the tire temperature during running higher than that of the conventional rubber for the entire rubber constituting the tire. Therefore, the effect of suppressing energy loss as a whole tire is great. On the other hand, the loss tangent (tan δ) of the tread rubber itself is small, and an increase in the coefficient of friction can be expected as the tire temperature increases. Accordingly, it is possible to improve the rolling resistance performance while maintaining or further improving the grip performance.

It is sectional drawing which shows one Example of the assembly of the pneumatic tire and rim | limb of this invention. 1 is a side view showing an example of a motorcycle equipped with an assembly of a pneumatic tire and a rim. It is a graph which shows the temperature dependence of the loss tangent (tanδ) of rubber.

  Hereinafter, embodiments of the present invention will be described in detail. In FIG. 1, the pneumatic tire and rim assembly 1 (sometimes simply referred to as the assembly 1) of the present embodiment includes a rim 2 and a pneumatic tire 3 attached to the rim 2. The cavity H is filled with a filling gas 5 made of high-humidity gas.

  The rim 2 has a known structure including an annular rim body 2A for fitting the tire 3 and a disk portion 2B for supporting the rim body 2A and fixing the rim body 2A to the axle, and various conventional rims are suitable. Can be adopted. In this example, a case where a regular rim is employed as the rim 2 is illustrated. The “regular rim” is a rim defined for each tire in the standard system including the standard on which the tire is based, and is a standard rim for JATMA, “Design Rim” for TRA, ETRTO Then means "Measuring Rim".

  Next, the pneumatic tire 3 includes a pair of bead portions 3a seated on the rim body 2A, a sidewall portion 3b extending radially outward from each bead portion 3a, and a tread portion 3c connecting between the radially outer ends. And has a known structure. In this example, the pneumatic tire 3 is a tubeless motorcycle tire, and the outer surface (tread surface) of the tread portion 3c curves in a convex arc shape from the tire equator Co to the tread end Te, and The tread width Tw, which is the distance in the tire axial direction between the tread ends Te, Te, makes the maximum tire width, thereby enabling cornering with a large bank angle.

  The pneumatic tire 3 has a toroidal carcass 6 that straddles the bead portions 3a and 3a and forms the skeleton of the tire, and a radially outer side of the carcass 6 and a tread portion 3c. Reinforced by a cord reinforcing layer including a tread reinforcing layer 7 disposed inside, necessary tire strength, tire rigidity, and the like are imparted.

  In the present invention, the filling gas 5 is filled in the tire lumen H surrounded by the rim 2 and the pneumatic tire 3.

The filling gas 5 is a high-humidity gas having a relative humidity of 60% or more at a temperature of 60 ° C. under 1 atm. In this example, air is used as the filling gas 5 for gas components other than water vapor. In other words, high-humidity gas containing high concentration of water vapor in the air is used.

Such a filling gas 5 can be filled into the tire lumen H by the following method. That is, for example, humid air having a relative humidity of 100% saturated with water vapor is formed at 1 atm and at a temperature T0 of 48.7 ° C. to 60 ° C. While heating, the pressure is supplied to the compressor and pressurized to the tire filling internal pressure ( 200 to 300 kPa) to fill the tire lumen H.

For example, when the filling gas 5 having a relative humidity of 60% at a temperature of 60 ° C. at 1 atm is filled in the tire lumen H at the tire filling internal pressure, the temperature is 1 atm and 48.7 ° C. Wet air having a relative humidity of 100% under T0 is formed. Such humid air having a relative humidity of 100% can be obtained directly using a commercially available humidity generator, humidity supply device, or the like. Alternatively, the humid air having a relative humidity of 100% can be obtained by preliminarily forming high-temperature and high-humidity humid air with a boiler or the like and cooling it while condensing it to the temperature T0 (48.7 ° C.). .

This humid air having a relative humidity of 100% at a temperature of 48.7 ° C. has a saturated water vapor amount of 78.0 g / m ³ and 60% of the saturated water vapor amount of 130.0 g / m ³ at a temperature of 60 ° C. (≈78. 0 / 130.0), that is, humid air having a relative humidity at a temperature of 60 ° C. of 60%. Then, the humid air having a relative humidity of 100% under the pressure of 1 atm and the temperature of 48.7 ° C. is pressurized to the tire filling internal pressure by a compressor and filled in the tire lumen H.

The reason why humid air with a relative humidity of 100% is used is that the amount of water vapor can be controlled by temperature and dew condensation, so that the absolute humidity of the filling gas 5 can be managed and controlled with high accuracy. A commercially available humidity generator, humidity supply device, etc. are used to directly form humid air with a relative humidity of 60% or higher at a temperature of 60 ° C. under 1 atm, and this is pressurized to the tire filling internal pressure with a compressor. Thus, the tire lumen H can be filled.

  Since such a filling gas 5 contains water vapor at a high concentration, the heat capacity is increased and the heat storage effect is enhanced. Therefore, the running tire temperature can be maintained higher than the conventional tire temperature. As a result, the loss tangent (tan δ) of the entire rubber constituting the tire 3 can be substantially reduced, and the effect of suppressing energy loss as the entire tire is increased. On the other hand, the loss tangent (tan δ) of the tread rubber itself is small, and an increase in the coefficient of friction can be expected as the tire temperature increases. Accordingly, it is possible to improve the rolling resistance performance while maintaining or further improving the grip performance.

In order to improve the rolling resistance performance, the relative humidity of the filling gas at a temperature of 60 ° C. under 1 atm is preferably 70% or more, more preferably 75% or more. The upper limit of relative humidity is 100%.

Further, in this example, as the filling gas 5, a case where water vapor is contained in air, that is, a gas component other than water vapor is air (about 20% oxygen and about 80% nitrogen by mass ratio) is exemplified. However, it is also preferable that the gas component other than the water vapor is nitrogen gas (nitrogen 100% by mass ratio).
This is because the deterioration of the member can be suppressed by using an inert gas such as nitrogen or helium having low reactivity.

  In addition, since the assembly 1 can maintain the gripping property as described above, when it is mounted on the motorcycle 10 as shown in FIG. 2, the occurrence of a fall due to the deterioration of the gripping property is suppressed. The function and effect of the assembly 1 can be exhibited most effectively.

  As mentioned above, although especially preferable embodiment of this invention was explained in full detail, this invention is not limited to embodiment of illustration, It can deform | transform and implement in a various aspect.

  In order to confirm the effect of the present invention, a motorcycle tire (tire size 120 / 70ZR17) is assembled to a rim (MT3.50 × 17) as a rim (MT3.50 × 17), a front wheel tire and rim assembly, and a tire (tire size 180). / 55ZR17) was assembled to a rim (MT5.50 × 17) as a rear wheel tire and rim assembly mounted on a domestic motorcycle (1300 cc) and tested for vehicle stability and grip. In addition, a drum test was also conducted on the rolling resistance performance of the rear wheel tire.

In the above test, the filled gas having the specifications shown in Table 1 was used only for the assembly for the rear wheel, and the air for the front wheel assembly (relative at a temperature of 60 ° C. under 1 atm.) As in the conventional example. Humidity 24.2%) is used. The filling internal pressure is 250 kpa for the front wheel assembly and 290 kpa for the rear wheel assembly.

(1) Steering stability and grip:
Using the vehicle, a running test is performed on the circuit course, and the driver's sensory evaluation of the steering stability (high-speed stability, turning performance, transient characteristics) and rear tire grip performance (grip limit height) at that time Thus, the conventional example was evaluated by a 5-point method with 3 points. A larger index is better.

(2) Rolling resistance performance:
Using a rolling resistance tester, rolling resistance was measured under the following conditions. The evaluation was performed using an index with the conventional example being 100. The smaller the index, the smaller the rolling resistance and the better.
Load: 1.8kN
Speed: 80km / h

  As shown in the table, it can be confirmed that the assembly of the example can improve the rolling resistance performance while maintaining or further improving the grip performance.

1 Assembly 2 Rim 3 Tire 5 Filling Gas

Claims (4)

Filling the tire lumen surrounded by the rim and the pneumatic tire attached to the rim with a filling gas at a filling pressure of 200-300 kPa ,
The filling gas, in a state before filling, the filling of the high moisture material relative humidity forms 60% or more and 90.7% or less, while warming so as not to Royui at a temperature 60 ° C. under 1 atm A pneumatic tire and rim assembly characterized by being filled up to a pressure .   The pneumatic tire and rim assembly according to claim 1, wherein the relative humidity of the filling gas is 75% or more. The pneumatic tire and rim assembly according to claim 1 or 2 , characterized in that the gas component other than water vapor is nitrogen gas. A motorcycle equipped with the pneumatic tire and rim assembly according to any one of claims 1 to 3 .

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