JP7439643B2 - Tire wear method and tire testing method - Google Patents

Description

The present invention relates to a tire wear method and a tire testing method.

Generally, the surface of a new tire is coated with release agents and oil from the tire vulcanization process, so in order to bring out the tire's original performance, it is recommended to run it for several tens to hundreds of kilometers. has been done. For this reason, when evaluating various running performances of a tire, the tread portion of the tire is abraded in advance using a bench abrasion tester or the like.

Patent Document 1 listed below describes an indoor tire wear test method. In this method, a suspension of talc is spread onto the running surface that the tire contacts. Talc prevents worn rubber separated from the tire tread surface during testing from re-adhering to the tread and adversely affecting test results.

Japanese Unexamined Patent Publication No. 7-146217

When the inventors carefully observed the tread of a tire worn by the method of Patent Document 1, it was found that a large amount of talc had penetrated deeply into the microscopic irregularities on the surface of the tread. It has also been found that it is difficult to completely remove such talc by cleaning with a brush or the like.

There is a problem in that the talc attached to the surface of the tread has a large effect on the running performance of the tire, particularly on performance evaluations such as on-snow and on-ice performance, which are related to the grip characteristics of the tread.

The present invention has been devised in view of the above-mentioned actual situation, and a main object of the present invention is to provide a tire abrasion method that can wear out the tread portion of a tire without affecting running performance. It is said that

The present invention is a method for wearing out a tread portion of a tire, and includes a step of running the tire with the tread portion in contact with the ground on a bench abrasion tester on which water-soluble powder is sprinkled; The tire wear method includes a cleaning step of washing the water-soluble powder adhering to the tread portion with water after the running step.

In another aspect of the invention, the cleaning step may include rubbing the tread portion with a brush.

In another aspect of the present invention, the water solubility of the water-soluble powder may be 30 (g/100gH ₂ O) or more at a water temperature of 20°C.

In another aspect of the present invention, the water-soluble powder may have a particle size of 5 to 50 (μm).

In another aspect of the invention, the water-soluble powder may be a nonflammable material.

In another aspect of the present invention, the water-soluble powder may be a non-deliquescent substance.

In another aspect of the invention, the water-soluble powder may be an inorganic salt.

Another aspect of the present invention may be a tire testing method that includes a step of testing the running performance of the tire using a tire worn by any of the tire wearing methods described above.

In another aspect of the present invention, the driving performance may be performance on snow or performance on ice.

In the present invention, by employing the above steps, water-soluble powder adhering to the tread portion can be easily removed after the running step. Therefore, the present invention can wear out the tread portion of a tire without affecting the original running performance of the tire.

FIG. 1 is a schematic diagram of a bench abrasion tester for carrying out the tire abrasion method of the present embodiment. It is a side view showing an example of a washing process. It is a graph showing the relationship between slip angle and cornering force for tires of Examples and Comparative Examples.

Hereinafter, one embodiment of the present invention will be described based on the drawings.
It should be understood that the drawings include exaggerated representations and representations that differ from actual dimensional proportions of structures to aid in understanding the present invention. In addition, when there are multiple embodiments, the same or common elements are denoted by the same reference numerals throughout the specification, and redundant explanation will be omitted. Furthermore, the specific configurations shown in the embodiments and drawings are for understanding the content of the present invention, and the present invention is not limited to the specific configurations shown.

[Bench wear tester]
FIG. 1 is a schematic diagram of a bench abrasion tester 1 for carrying out the tire abrasion method of this embodiment. The bench abrasion tester 1 of this embodiment is of a drum type and includes a rotatable metal drum 3 for running a tire 2.

A running surface 4 for running the tire 2 is continuously formed on the outer surface of the drum 3. Thereby, the bench wear tester 1 forms an endless road surface. In other embodiments, the bench abrasion tester 1 may be of a flat belt type instead of a drum type.

The running surface 4 is formed of, for example, a replica road surface imitating asphalt. Such a replica road surface may be formed of a mixture of resin and silicon, for example. In other embodiments, in order to accelerate wear of the tires 2, a non-slip surface material with a high coefficient of friction, such as Safety, Walk (registered trademark of 3M Company), may be used on the running surface 4.

The bench abrasion tester 1 of this embodiment is provided with a scattering device 5. The spraying device 5 includes a nozzle 6 for spraying water-soluble powder 7 (details will be described later) toward the running surface 4 . The spraying device 5 can spray the water-soluble powder toward the running surface 4 using, for example, high-pressure air.

[Wear method]
Next, a method for wearing out the tread portion 2a of the tire 2 of this embodiment will be explained. The wear method of this embodiment includes a running step and a cleaning step.

[Traveling process]
In the running step, the tire 2 is run on the bench abrasion tester 1 on which the water-soluble powder 7 is sprinkled, with the tread portion 2a of the tire 2 in contact with the ground.

Specifically, as shown in FIG. 1, the tread portion 2a of the tire 2 is arranged so as to be in contact with the running surface 4 of the bench abrasion tester 1. At this time, the tire 2 is rotatably supported by a tire holding section (not shown).

Further, a predetermined load is applied to the tire 2, and therefore the tread portion 2a is pressed against the running surface 4 of the drum 3.

Thereafter, the drum 3 is driven to rotate in direction A. As a result, the tire 2 in contact with the drum 3 is rotated (run) on the drum 3 in the opposite direction to the drum 3.

Further, for example, while the tire 2 is running, the water-soluble powder 7 is sprayed from the spraying device 5 toward the running surface 4 . In this embodiment, the water-soluble powder 7 is sprinkled toward the first arrival side (depression side) of the tire 2 in the rotational direction. Therefore, the water-soluble powder 7 adheres to the running surface 4 of the drum 3, and can then also adhere to the tread portion 2a that comes into contact with the running surface 4.

During the running process, the tread portion 2a of the tire 2 gradually wears out due to abrasion energy generated by contact with the running surface 4 of the drum 3. That is, the rubber on the surface of the tread portion 2a is worn away. On the other hand, the sprinkled water-soluble powder 7 adheres to the tread portion 2a and the running surface 4, and prevents the rubber powder etc. scraped from the tread portion 2a from adhering to the tread portion 2a and the running surface 4 again. . As a result, the tread portion 2a of the tire 2 wears to a state similar to that when the tire is actually driven on an asphalt road surface.

[Washing process]
In the cleaning process, the water-soluble powder adhering to the tread portion 2a after the running process is cleaned using water. The washing step can be performed in various ways. As the simplest method, the cleaning step may be performed by spraying water onto the surface of the tread portion 2a of the tire 2. As a result, the water-soluble powder 7 remaining on the surface of the tread portion 2a is dissolved in the water that comes into contact with it, and is easily removed from the tread portion 2a.

As described above, the tire 2 wear method of the present embodiment solves the problem that powder, which is a foreign substance, remains on the tread portion 2a of the tire 2 after the cleaning process, and further improves the surface condition of the tread portion 2a on the actual vehicle. It is possible to approximate the wear form and surface condition during driving. Therefore, the wear method of this embodiment can wear the tread portion 2a of the tire 2 without affecting the original running performance of the tire 2.

In a preferred embodiment, the cleaning step can include a step of rubbing the tread portion 2a with a brush. In such an embodiment, the water-soluble powder 7 is not only dissolved in water and removed from the surface of the tread portion 2a, but also the water-soluble powder 7 that is not sufficiently dissolved is physically removed from the surface of the tread portion 2a. You can also do it. Therefore, the tread portion 2a can be cleaned in a short time.

FIG. 2 shows yet another example of the cleaning process. As shown in FIG. 2, the tire 2 that has completed the running process is placed in a cleaning device 10, for example. The cleaning device 10 includes a frame 11 capable of storing water and a plurality of brush rolls 12 arranged on the frame 11. The lower part of the brush roll 12 is immersed in water W stored in the frame 11. By rotating the tire 2 supported by the brush rolls 12, 12, the tread portion 2a comes into contact with water and the brush roll 12 and is cleaned. Washing water may be separately sprayed onto the tread portion 2a.

[Solubility of water-soluble powder]
The water-soluble powder 7 is not particularly limited as long as it dissolves in water to form an aqueous solution, but the higher the solubility, the more desirable it is. This makes it possible to remove the water-soluble powder 7 on the surface of the tread portion 2a with a small amount of cleaning water. In a preferred embodiment, the water solubility of the water-soluble powder 7 is, for example, 10 (g/100 g H ₂ O) or more, particularly 20 (g/100 g H ₂ O) or more, at a water temperature of 20° C. (under atmospheric pressure). It is desirable that it is 30 (g/100gH ₂ O) or more.

[Particle size of water-soluble powder]
There are no particular restrictions on the particle size of the water-soluble powder 7, but if it becomes too large, the wear pattern may be far different from that of an actual vehicle on a normal asphalt-paved road. From this point of view, the particle size of the water-soluble powder 7 is preferably about 5 to 50 μm, for example.

[Nonflammability of water-soluble powder]
In order to ensure explosion-proof properties in an environment in which the abrasion method of this embodiment is carried out, the water-soluble powder 7 is desirably made of, for example, a nonflammable material, particularly a noncombustible inorganic material.

[Deliquescent property of water-soluble powder]
It is desirable that the water-soluble powder 7 is, for example, a non-deliquescent substance. When the water-soluble powder 7 has deliquescent properties, it absorbs water vapor in the air and dissolves during the abrasion method, and there is a possibility that it will not be able to maintain a minute particle size. On the other hand, the use of water-soluble powder 7 without deliquescent properties is desirable because the influence of humidity can be eliminated from the atmosphere in which the abrasion method is performed. However, if the environment in which the abrasion method is carried out is not a humid environment, the deliquescent nature of the water-soluble powder is not so important.

[Typical example of water-soluble powder]
As the water-soluble powder 7, for example, inorganic salts such as sodium chloride, magnesium sulfate, and magnesium chloride are desirable.

[Performance test after wear method]
In a preferred embodiment, the running performance of the tire is tested using the tire worn out by the wearing method of this embodiment. In the tire 2 worn by the wear method of this embodiment, no water-soluble powder remains on the tread portion 2a of the tire 2 after the cleaning process, and a wear state close to that of the running-in of an actual vehicle can be obtained. Therefore, it becomes possible to test the original running performance of the tire 2 more accurately using the tire worn out by the wearing method of this embodiment.

The running performance of the tire to be tested is not particularly limited, but it is preferably performance on ice or performance on snow that is greatly affected by the grip performance of the tread portion 2a. This is because, in the abrasion method of this embodiment, since there is no adhesion of water-soluble powder 7 (foreign matter) to the surface of the tread portion 2a, it is possible to evaluate the grip performance of the tread portion 2a with higher accuracy.

Although the embodiments of the present invention have been described in detail above, the present invention is not limited to the above-mentioned specific disclosure, and can be implemented in various ways within the scope of the technical idea described in the claims. It can be modified and implemented.

More specific and non-limiting embodiments of the invention will now be described.

[Example wear test]
In the example, a running process was performed using a bench abrasion tester while spraying the following water-soluble powder. Thereafter, as a cleaning step, one worker washed the tread with water for about 5 minutes while rubbing the tread with a brush. Afterwards, an on-ice performance test was conducted. Details are as follows.

<Water-soluble powder>
Material: Magnesium sulfate (manufactured by Ako Kasei)
Particle size: 10 (μm)
Flash point: Nonflammable Solubility (@water temperature 20°C): 30 (g/100gH ₂ O)
Deliquescence: None Spraying amount: 0.3 (g/sec)

<Traveling process>
Tire size: 195/65R15 91Q (studless tire)
Internal pressure: 230 (kPa)
Load: 3.80 (kN)
Drum speed: 50, 60, 100 (km/h)
Running time: 1 hour

<Ice performance test>
Cornering force was measured under the following conditions using a bench cornering force tester with an icy road surface.
Internal pressure: 230 (kPa)
Load: 3.80 (kN)
Drum speed: 15 (km/h)
Tire speed: 15 (km/h)
Slip angle: 0~5 (°)

[Comparative example]
As a comparative example, the water-soluble powder of the example was replaced with powdered talc, and the same running process, washing process, and performance test on ice were conducted.

[Evaluation of test results]
The results of the on-ice performance test are shown in Figure 3. In FIG. 3, the horizontal axis represents the slip angle, and the vertical axis represents the cornering force. Moreover, the solid line shows the test result of the example, and the virtual line shows the test result of the comparative example. Furthermore, the broken line is the ice performance test of the tire that was run-in on an actual vehicle (reference example). The break-in run consisted of driving around the city for approximately the same distance as the driving process of the example and comparative example.

In FIG. 3, focusing on the maximum value of cornering force, there is a deviation of about -9% in the comparative example compared to the reference example. In particular, in the comparative example, the cornering force decreases more as the slip angle increases. This is presumably because the talc remaining on the surface of the tread portion after the wear test deteriorated the grip performance, and as a result, the slip area of the tire increased.

On the other hand, the example showed almost the same value as the reference example regarding the maximum value of cornering force. Furthermore, it was confirmed that in the example, the change in cornering force with respect to the slip angle also showed the same tendency as in the reference example.

1 Bench abrasion tester 2 Tire 2a Tread section 7 Water-soluble powder

Claims (9)

A method for wearing out a tread portion of a tire, the method comprising:
a running step of running the tire with the tread portion in contact with the ground on a bench abrasion tester on which water-soluble powder is sprinkled;
After the running step, a washing step of washing the water-soluble powder adhering to the tread portion with water,
How to wear tires. The tire wearing method according to claim 1, wherein the cleaning step includes a step of rubbing the tread portion with a brush. The tire wear method according to claim 1 or 2, wherein the water solubility of the water-soluble powder is 30 (g/ _100gH2O ) or more at a water temperature of 20C. The tire wearing method according to any one of claims 1 to 3, wherein the water-soluble powder has a particle size of 5 to 50 (μm). The method for wearing a tire according to any one of claims 1 to 4, wherein the water-soluble powder is a nonflammable substance. The tire wearing method according to any one of claims 1 to 5, wherein the water-soluble powder is a non-deliquescent substance. The tire wearing method according to any one of claims 1 to 6, wherein the water-soluble powder is an inorganic salt. A tire testing method comprising the step of testing the running performance of a tire using a tire worn out by the tire wearing method according to any one of claims 1 to 7. The tire testing method according to claim 8, wherein the running performance is performance on snow or performance on ice.

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