JPS5830163B2 - pneumatic tires - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a structure of a pneumatic tire that allows the degree of wear to be easily checked visually.

BACKGROUND ART In recent years, as roads have been improved, cars have started to travel at higher speeds, and as a result, serious car accidents that can lead to death have become more frequent.

Due to this background, the automobile industry is rushing to develop 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 allows drivers and managers to visually check whether the tires currently in use are in an abnormal state of use, and even if they are abnormal, 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 tires by making it clear through One or more sets of wear detection units capable of displaying the degree of tire wear are arranged protrudingly at certain locations, and the wear detection units come into contact with the road surface under abnormally low air pressure, causing wear on the tire. It is characterized by a configuration that makes clear the running durability limit of the vehicle.

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-coated 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 the above tire, a portion of the sidewall rubber layer 5 extending from the shoulder 6 adjacent to the tread rubber layer 4 to the side wall may come into contact with the road surface if the normal air pressure is maintained when the vehicle is running when the tire is mounted on the vehicle. In case of abnormally low air pressure, one or more sets of wear detection units, which are the characteristics of the present invention, are protruded and arranged at appropriate locations in contact with the road surface, for example, on the shoulder 6, and the wear detection units have wear characteristics. consists of at least two protrusions 7, 7' formed in the same shape and made of different materials such as rubber, and the wear detection unit is adhered to the sidewall rubber layer 5 during molding,
Then, they are simultaneously integrally molded during vulcanization molding.

Note that the wear detection unit can also be provided using an adhesive after vulcanization molding.

In the tire of the above example, as shown in the front view of the tire in Fig. 2, wear detection units consisting of two protrusions T and 7' are protrudingly arranged in four equal parts on the circumference of the tire. The number of units may be one or more, and it is important to arrange them with consideration to maintaining the rotational balance of the tires, and the number of protrusions in one detection vehicle position is limited to two. There may be two or more of them, and they do not necessarily need to be arranged adjacently.

However, it goes without saying that it is preferable to arrange them adjacently as in this example because the difference in the degree of wear can be clearly understood by comparing them.

The shapes of the protrusions 7, 7' can be various shapes such as a trapezoidal shape shown in FIGS. 1 and 2, a cylindrical truncated shape, a truncated truncated cone, etc.; It is also possible to consider an unusually shaped one.

This protrusion 7 has a structure in which each side simply protrudes from the shoulder 6 as described above, but a part of the periphery of the protrusion is formed into a recess 8,
It is designed to facilitate the deformation of the protrusions, and if it is formed on the type of tire that has the protrusions 7 and 1' shown in Figs. 1 and 2, it will induce abnormal vibrations during high-speed running. However, it has the feature of suppressing the occurrence of such abnormal vibrations and eliminating discomfort for passengers.

Note that the protrusions I and γ′ are arranged at the shoulder portion 6;
If the tire pressure is at the specified pressure, it will not come into contact with the road surface,
A portion that comes into contact with the road surface at a pressure of 80 or less of the specified pressure, preferably a portion that can come into contact with the road surface at a pressure of 40φ or less of the specified pressure, is suitable.

And each protrusion 1. It is desirable that γ' be arranged in the same circumferential direction of the tire.

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 present invention is to use the fact that rubber I and rubber II, which have different rubber compositions, have different amounts of wear under the same conditions to estimate the usage conditions, and this principle is the most effective. It is used 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, if the rubber compound is selected in advance so that all of the protrusions 1 and 7' are completely worn down to the surface of the shoulder 6 just before the time when the tire failure limit is reached, the worst case condition can be avoided. This means that it is possible to clarify the durability limit when using a tire.

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), so tire air pressure is lower than the specified pressure. When the height drops to about 40 yen, by placing the protrusions 1 and 7' in contact with the road surface, the protrusions 7 and 7' will receive frictional resistance from the road surface against the decrease in air pressure and overload, and the desired result will be achieved. When the purpose is sufficiently achieved and the wear difference between the protrusions 7 and 7' made of different rubber compositions reaches a value equal to that, the tire approaches its durability limit and reaches a dangerous state. It is also possible to prove this experimentally, and in this way, it is possible to know the safety limit of the tire by visually observing the wear difference between the protrusions 7° and 7', which have different wear characteristics, and the complete wear of all the protrusions. can.

Here, the amount of wear of the protrusions 7 and 7', which have different wear characteristics, can be calculated from the above equation by α and β, assuming that the amount of wear of the rubber I with the larger amount of wear and the amount of wear of the rubber ■ with the smaller amount are W and W2.・If nl・R2 is known, it goes without saying that the wear difference can be easily determined in relation to the speed.

Note that the protrusion 7. As shown in Figure 11, γ' is formed into a double layer with different hues for each protrusion, and the outer layer (R1)
If the inner layer (R2) is made of black rubber, which is the same color as a regular tire, and the inner layer (R2) is buried to a predetermined size from the outer layer surface and is made of rubber of a color other than black, such as red, in addition to warning of abnormal use, a color warning will be issued. It is preferable that a danger warning can be displayed, but it is also preferable that this colored layer is not limited to two layers, but that the degree of wear progression is displayed based on the color difference between the colored layers and the layered layers, which have mutually different colors.

As described above, the present invention provides at least two wear detection units each formed with a set of at least two protrusions 7, 7' made of different materials having different wear characteristics when detecting the abnormally low air pressure of a pneumatic tire on the road surface. Since the protrusions are arranged in areas that can come into contact with the protrusions 7, 7', it is possible to know when the tire has reached its running durability limit by visually observing the degree of wear on the covers of the protrusions 7 and 7', thereby preventing overuse of the tire. This is extremely effective in ensuring the safety of passengers, since it is possible to prevent major accidents from occurring due to tire damage.

Furthermore, it goes without saying that the 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. It is truly useful and innovative from the standpoint of safety, as it can visually notify the driver of tire wear and tear during pre-driving inspections, ensuring personal protection, and is of great benefit to the industry. It is a pneumatic tire that takes a lot of processing time.

[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 1 A2
The opening is a front view of a protrusion according to an example of the tire of the present invention, FIG. 8 is an enlarged cross-sectional view along arrow A-A in FIG. 10 is an enlarged cross-sectional view taken along the line CC at the mouth of FIG. 1, and FIG. 11 is a longitudinal sectional view of a protrusion according to 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. γ'... Protrusion, 8...
・Concavity.

Claims (1)

[Claims] 1. It forms part of the surface layer from the shoulder adjacent to the floor area to the side wall, and when the vehicle is running with normal air pressure, it does not come into contact with the road surface, but under abnormally low air pressure, it touches the road surface at appropriate locations. One or more sets of wear detection units each formed with a set of at least two protrusions 7, 7' made of different materials having different wear characteristics are arranged in a protruding manner to detect the wear detection unit when traveling under abnormally low air pressure. A pneumatic tire characterized in that the running durability limit of the tire can be clearly indicated since the protrusions 7, 7' come into contact with the road surface and cause wear of the cap.