JPS599361B2 - pneumatic tires - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a structure of a pneumatic tire that allows the durability limit of the tire to be easily confirmed visually when the tire is running under abnormal conditions.

In recent years, as roads have been improved, cars have started to travel at higher speeds, and car accidents have become more likely to become serious.

Due to this background, the automobile industry is urgently developing safer cars, while the tire manufacturing industry is currently also working hard to develop tires that are highly safe at high speeds.

By complying with the conditions of air pressure, load, and speed that are clearly defined as normal conditions for tires, that is, those that allow tire performance to be maximized, the probability of a major accident occurring will be extremely small.

Unfortunately, however, there are many cases where drivers continue to drive with low air pressure without being aware of small air leaks caused by external injuries while driving, and as a result, physical fatigue of tire cords, etc. is accelerated, leading to major accidents. However, it is well known that there is a problem in which complete safety management cannot be achieved with pre-trip inspections alone.

The present invention focuses on the current situation and makes it possible to check whether the tires currently in use are in an abnormal state of use, and even if they are abnormal, to display the extent of the abnormality and whether or not they can be continued to be used. The main objective is to provide a new tire that can improve the safety performance of the tire by making it visually clear to drivers and managers. By protruding one or more steps made of an abrasive material that can indicate the degree of tire wear at appropriate locations on the tire that do not come into contact with the tire, the higher part of the step may contact the road surface under abnormally low air pressure. Since contact with the tires causes wear changes, the tire is characterized by a structure that makes the running durability limit of the tire clear.

Hereinafter, specific embodiments of the present invention will be clarified based on the accompanying drawings.

FIG. 1 is a cross-sectional view of the right half of an example of the tire of the present invention taken in the axial direction, and shows a bead portion 1 having at least one pair of bead wires 2, and a bead portion 1 extending in series between the bead wires 2. A ply layer 3 consisting of one or more layers of rubber-covered letter cord, a tread rubber layer 4 disposed on the outer tread portion of the ply layer 3, and a sidewall rubber layer 5 similarly disposed on the side wall portion. The bead portions 1, 1 are fitted onto the automobile rim 9, and the inner space is filled with air.

In a Doki tire, it is a part of the sidewall rubber layer 5 that extends from the shoulder 6 adjacent to the tread rubber layer 4 to the sidewall and forms the outer layer of the tire, and maintains normal air pressure while driving when mounted on a vehicle. In some cases, there is no contact with the road surface, but under abnormally low pressure, one or more stepped portions as wear detectors are disposed at appropriate locations, such as the shoulder portion 6, in contact with the road surface. However, the stepped portion has a high portion and a low portion adjacent to each other, and the high portion is formed of a protrusion 7 made of a material that is more abrasive than, for example, the sidewall rubber of the tire body, such as rubber. , while simultaneously integrally molding the sidewall rubber layer 5 during vulcanization molding, the lower portion utilizes the surface portion of the sidewall rubber layer 5.

As shown schematically in the front view of the tire in Fig. 2, in the case of the tire in the above example, when arranging multiple tires, it is important to consider the point that they are arranged so as to equally divide the circumference of the tire to maintain the tire rotational balance. Preferably, they are provided on one circumference or at positions shifted in the radial direction.

In addition to the trapezoidal shape shown in FIGS. 1 and 2, the protrusion 7 can have various shapes such as a cylindrical truncated shape and a truncated truncated cone. Furthermore, the protrusion 7 can have various shapes such as the trapezoidal shape shown in FIGS. 1 and 2. One can also be considered.

This protrusion 7 has a structure in which it simply protrudes from the shoulder part 6 in the above-mentioned examples, but a part of the periphery of the protrusion 7 is formed into a recess 8, and the bending rigidity of the protrusion is extremely extreme compared to the shoulder part 6. However, if the protrusions 7 shown in Figures 1 and 2 are formed on certain types of tires, there is a risk that abnormal vibrations will be induced during high-speed driving. On the other hand, it has the feature of suppressing the occurrence of abnormal vibrations and eliminating discomfort for passengers.

The location of the protrusion 7 is the shoulder 6, where the tire does not come into contact with the road surface when the tire pressure is at the specified pressure, but does come into contact when the tire pressure is 50 parts or less of the specified pressure, preferably 40 parts or less of the specified pressure. In this case, a portion that can come into contact with the road surface is practically preferable.

In addition, in the case where a plurality of protrusions 7 are provided with their positions shifted in the radial direction, for example, when the specified air pressure is 5.
By providing protrusions 7 on the parts of the tire that contact the road surface at pressures below 0, below 40, below 30, and below 20, it is possible to determine the tire's air pressure by knowing the degree of wear on each of these protrusions. It becomes possible to qualitatively and quantitatively check whether the tire has been driven under the conditions, and furthermore, it is of course possible to provide the protrusion 7 not only on one side of the tire but also on both the outer and inner sides of the tire. Each example is highly preferred.

The wear detection function of the pneumatic tire configured as described above will be explained with reference to the characteristic diagrams shown in FIGS. 3 to 6.
Rubber normally used in tires has wear characteristics that are approximately proportional to the n-th power of speed under equal load and equal air pressure, as shown in FIG. 3, and differences in characteristics occur due to differences in rubber composition.

Therefore, the principle of the above embodiment is to try to estimate the usage conditions by utilizing the fact that rubber 1 and rubber (2), which have different rubber compositions, have different amounts of wear under the same conditions.
This principle is most effectively utilized when driving with a flat tire.

Figure 4 shows the results of actual measurements under a constant load of the time course until the tire breaks when the tire is driven with a flat tire, using the traveling speed as a reference.As is clear from this figure, the speed As the value increases, the durability time decreases.

Based on these characteristics, the rubber material has a greater degree of wear than the rubber material of the shoulder part 6 so that all of the protrusions 7 are completely worn down to the surface of the shoulder part 6 before reaching the tire failure limit. If the protrusion 7 is formed using a tire, it is possible to clearly indicate the durability limit when the tire is used in the worst condition.

Furthermore, the endurance limit running time of pneumatic tires fluctuates significantly with changes in air pressure (see Figure 5), and changes greatly with changes in load (see Figure 6). When the pressure drops to about 40 coefficients, by placing the protrusions 7 in contact with the road surface, the protrusions 7 will receive frictional resistance from the road surface against the decrease in air pressure and overload, and the intended purpose will not be fully achieved. In addition, when the difference in wear between the protrusion 7 and the outer layer of the tire around it reached a certain value, it was experimentally confirmed that the tire almost approached the wear limit and reached a dangerous state. In this way, the wear difference occurring between the tire outer layer and the protrusions 7 and the complete wear of all protrusions can be visually observed to determine the usage and safety limits of the tire.

The amount of wear on the protrusion I is W1, which is the wear on the outer layer of the tire.
α, β, γ1 rnl 2 in equations (a), (mouth), and (c)
rn2 2”3 1 n1 1 n/, l n2
j ''2 j n3 1 n/3 is experimentally obtained as a constant.

Therefore, if both wear amounts (W, ) and (%) can be measured, ■ and t can be obtained from both equations (a) and (0).

Note that Δ can be estimated by visually observing at which position the protrusion 7 is worn.

As a result, the degree of tire damage (D) can be determined as a function of W1 and W2.

The amount of wear on the outer layer of the tire can also be measured by forming irregularities on the layer at a location separate from the stepped portion, or in the case of the example shown in Figure 8, it can be measured in the vicinity of the protrusion T. is also possible.

As shown in Figure 11, the protrusions 7 are formed in two layers with different hues for each protrusion, and the outer layer R1 is made of black rubber, which is the same color as the tire, and is buried a predetermined distance from the surface of the outer layer by one distance. It is preferable that the inner layer R2 is formed of rubber of a color other than black, such as red, since it is possible to display a danger warning in a dark blue color in addition to a warning of abnormal use.However, this colored layer is also limited to two layers. It is also a preferable embodiment to display the degree of wear progress through the use of mutually different colored graded layers and color differences, and to provide a subdivision scale on the side circumferential surface of the protrusion made of one color of rubber.

Further, in the tire according to the present invention, as for the step portion formed in the tire surface layer, the high portion is formed by the protrusion 7 and the low portion is formed by the outer surface portion of the tire outer layer portion, as in the above example, and the protrusion 7 is made of a specific material. This is an integrated arrangement.

The material of this protrusion 7 is limited to a specific rubber material having physical properties such that the amount of wear W1 is proportional to the degree of damage to the tire surface layer, that is, satisfying 2K, for example, J ``m1, n2= m2,
By selecting a material that satisfies the condition n3=rn3, knowing the amount of wear on the protrusion 7 will indicate the degree of damage, and it can be easily managed by the vehicle operator without the need for any special conversion means. There are advantages that can be achieved.

In each of the following examples, the protrusion T serving as the higher part may have various shapes. For example, as shown in FIG. Arranged with a small gap (see Figure 12 A)
Alternatively, the top surface of one protrusion 7 may have a toothed structure in which concave and convex portions are arranged alternately in the direction from the side wall of the tire toward the tread surface (see Figure 12); By visually observing which convex parts are worn out, the correspondence with air pressure can be determined, which is extremely effective in practical use.

As described above, in the present invention, at least one stepped portion made of an abrasive material is formed in a portion of the pneumatic tire that can come into contact with the road surface under abnormally low air pressure, so that the degree of wear in the higher portion of the stepped portion is reduced. By visually observing the tire, it is possible to know when the tire has reached its driving durability limit, which prevents overuse of the tire and eliminates the occurrence of a major accident due to tire damage. It is extremely effective for measurement.

In addition, the step part as a wear detection unit can not only display the tire usage limit in a one-time abnormal run, but also accurately display the degree of tire fatigue in the case of an accumulation of short-term abnormal runs. Needless to say, this system is truly useful and innovative from a safety standpoint, as it can visually notify the driver of tire wear and tear during a pre-trip inspection. This is a great pneumatic tire that will benefit the world.

[Brief explanation of drawings]

FIG. 1 is a cross-sectional view of the right half of an example of the tire of the present invention, FIG. 2 is a front view thereof, and FIGS. 3 to 6 are characteristic diagrams for explaining the wear detection function of the tire of the present invention. , Figure 7 A,
The opening is a front view of such a protrusion in Example C of the tire of the present invention, No. 8.
The figure is an enlarged cross-sectional view taken along the line A-A in Figure 7A, Figure 9 is an enlarged cross-sectional view taken along the line B-B at the mouth in Figure 7A, and Figure 10 is an enlarged cross-sectional view taken along the line C-C at the mouth in Figure 7. 11 is a longitudinal cross-sectional view of a protrusion according to an example of the tire of the present invention, and FIG. 12A is a partial cross-sectional view of an example of the tire of the present invention. 1...Bead portion, 2...Bead wire, 3...Ply layer, 4...Tread rubber layer, 5...Side wall Rubber layer, 6...
...Shoulder, 7...Protrusion, 8...Concavity.

Claims (1)

[Claims] 1. It forms a part of the outer layer consisting of the shoulder and side wall adjacent to the tread, and when the vehicle is installed and the vehicle is running, it does not come into contact with the road surface under normal air pressure, but it contacts the road surface at abnormally low air pressure at appropriate locations. a lower part integrally formed of the same tissue as the outer layer part, and a lower part having a lower wear resistance than the outer layer part;
In addition, at least one stepped portion is formed adjacent to a high portion integrally formed of a different material that can exhibit a change in the amount of wear proportional to the degree of damage to the tire itself, so that the tire can be driven under abnormally low air pressure. 1. A pneumatic tire characterized in that the high part of the stepped part is made to be able to clearly indicate the running durability limit of the tire due to wear changes caused by contact with the road surface.