JPH1110746A - Method for repairing radial tire - Google Patents

Abstract

PROBLEM TO BE SOLVED: To suppress strength decrease and fatigue of ply cord at a side protrusion and recess site even in the case of aging use by adhering a reinforcing material to an inner surface side of a tire at the side protrusion and recess site. SOLUTION: When an external damage or rubbed damage occurs at a side of a carcass layer 6 of a radial tire 1, a protrusion and recess A (side protrusion and recess site A) is locally generated at its part. This occurs due to that a ply cord 5 is plastically deformed. Thus, a reinforcing material 11 of a patch-like state is adhered to an inner surface side of the tire of the side protrusion and recess site A with adhesive to be reinforced. As the material 11, repairing patch sold in the market is used, formed of rubber, and embedded with many rayon cords 12 at an interval therein. The cords 12 are disposed in its axial direction toward a tire radial direction, and adhered. In this case, tension of the cord 5 is loaded particularly to the cords 12 to alleviate tension loading of the cord 5, thereby suppressing progress of strength decrease and fatigue.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for repairing a pneumatic radial tire, and more particularly, to a method for repairing a side uneven portion of a radial tire for correcting a large radial tire for a truck, a bus or a small truck. About.

[0002]

2. Description of the Related Art Conventionally, radial tires for trucks and buses have been manufactured with emphasis on strength, durability, abrasion resistance, traction force, etc., from the intended use. Thicker or increased ply cords are used.

[0003] In general, the life of a tire is governed by road surface conditions, use conditions, driving conditions, and the like. In particular, the life of a tire operated under a high load such as for trucks and buses has a problem in terms of durability. become. The main factors that affect the durability of the tire include abrasion, trauma, separation (peeling of the trade rubber and the cord layer and peeling between the cord layers), breakage of the cord, and the like.

[0004] In the radial tires for trucks and buses, a factor that hinders the durability that affects the service life is that irregularities may be generated (generated) on side portions of the tire. The occurrence of the unevenness on the side portion of the tire determines the life of the tire used after the occurrence of the unevenness. Then, at the time of acceptance inspection of the base tire, etc., if the side portion unevenness is recognized by the tactile sensation of the inspecting person's hand, it is not used thereafter, measures such as disposal are taken, and the side portion unevenness is repaired. At present, there is no rehabilitation of such tires.

[0005]

Problems to be solved by the present invention By analyzing the unevenness of the side portion of the radial tire on the basis of the phenomenon, the unevenness of the side portion is generated by an external scratch or a scratch generated on the side portion. It is clear that the ply cord in the side portion is plastically deformed, and the side portion unevenness is formed by the plastic deformation. Further, it was found that there is a correlation between the deformation curvature of the ply cord and the ply strength / fatigue, and that as the deformation curvature increases, the ply strength decreases and the fatigue increases significantly.

When the radial tire is run in a state in which the side surface irregularities are generated, a decrease in the ply strength and an increase in fatigue gradually progress due to a temporal change (running distance) due to the running, and eventually. , CBU (code breaking up).

[0007] The area where the CBU (code breaking up) occurs is a dangerous area that may cause damage to the ply cord, and it is dangerous to use the side unevenness without repairing it. In addition, there is also a problem from an economic point of view in that measures such as disposal are carried out without repairing and repairing the radial tire having the side surface irregularities.

[0008] The present invention has been made in view of such a problem, and an object of the present invention is to provide a radial tire which is necessary when irregularities occur on its side due to external damage or scratches. A method of repairing a radial tire that suppresses the deterioration of the ply cord of the side surface irregularities and prevents the tire strength from increasing and increasing fatigue even when the radial tire is changed over time by continuous running by performing treatments and the like. It is to provide.

[0009]

In order to achieve the above object,
The method for repairing a radial tire according to the present invention is a method for repairing a side uneven portion generated in a radial tire provided with a ply cord, wherein a reinforcing material is attached to a tire inner surface side of the side uneven portion, and the reinforcement is performed. The material is made of a patch-like rubber body, in which a rayon cord is embedded, and the rayon cord is stuck to the tire in the radial direction.

As the organic fiber cord embedded in the reinforcing material, rayon cord is preferable.
An aliphatic polyamide fiber cord such as 6,6-nylon or a polyester fiber cord such as polyethylene terephthalate may be used.

By applying the above-mentioned repair method to the radial tire having the uneven portion formed on the side portion, the ply tension of the radial tire is borne by the reinforcing material, and the ply tension of the ply cord is reduced. That is,
By attaching the reinforcing material to the side irregularities, the ply tension of the attached portion is divided and shared between the ply cord and the reinforcing material, and the burden of the ply tension of the ply cord is reduced.

In addition, the deformation behavior of the ply cord when the radial tire is loaded is such that when the reinforcing material is attached, the deformation radius of curvature is larger than the deformation radius when the reinforcing material is not attached. It becomes smaller and the amount of deformation becomes smaller.

Further, even when a reinforcing material is stuck,
Fatigue increases with time (running distance) due to running, but the degree of fatigue is extremely small compared to the case where no reinforcing material is stuck, and does not reach the CBU generation area even when the running distance reaches 50,000 km. Therefore, it is possible to suppress fatigue based on a change with time (running distance) due to running.

Further, even when the reinforcing material is adhered, the strength is reduced according to the change with time (running distance) due to running, but when the reinforcing material is not attached, the strength is significantly reduced. The degree of decrease is small, and although there is a decrease in the strength of the ply cord due to aging over time,
The decrease in the strength of the ply cord can be suppressed to a small extent, and the radial tire can be used for a long time.

[0015]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of a method for repairing a side uneven portion of a radial tire according to the present invention will be described below with reference to the drawings. FIG. 1 is a sectional perspective view of a pneumatic radial tire 1 of the present embodiment, and FIG. 2 is a sectional view of the radial tire 1 of FIG.
It is II-II arrow sectional drawing.

The pneumatic radial tire 1 shown in FIG.
A tire for trucks and buses, which has a loop shape in cross section and is entirely formed of a rubber layer 2. A pair of bead cores 4, 4 formed in a ring shape around the rotation axis of the radial tire 1 are provided at bead portions 3 at both ends of the cross section of the radial tire 1. Between the pair of bead cores 4, a two-layer carcass layer 6 composed of ply cords 5 arranged in a loop in the cross-sectional direction of the radial tire 1 is provided. Both ends in the longitudinal direction of the carcass layer 6 are turned up around the pair of bead cores 4 and 4.

On the radially outer side of the carcass layer 6, a two-layered steel belt layer 8 made of a non-extensible steel cord 7 is arranged. Outside the steel belt layer 8 in the tire radial direction, the steel belt layer 8 is provided. A thick tread portion 9 is formed so as to cover 8. A plurality of rib grooves (circumferential grooves) 10 extending continuously in the circumferential direction of the radial tire 1 are formed on the surface of the tread portion 9 at predetermined intervals in the width direction of the radial tire 1. .

The pneumatic radial tire 1 having the above-described configuration is manufactured, and the radial tire 1 is mounted on a truck, a bus, or the like, and travels.
When external damage or abrasion occurs on the side portion of the carcass layer 6 of the radial tire 1, the radial tire 1
Locally unevenness A (hereinafter, referred to as side unevenness portion A) in the portion of the side portion where the above-mentioned trauma or abrasion has occurred.
Is generated. As shown in FIG. 2, the side uneven portion A is generated by the plastic deformation of the ply cord 5.

For this reason, a patch-like reinforcing material 11 is adhered to the tire inner surface side of the side uneven portion A with an adhesive to reinforce the side uneven portion A. The reinforcing material 11 can be a commercially available repair patch (Tip Top 140TL) or the like. As shown in FIG. 3, the reinforcing material 11 is formed of a rubber body and has a large number of rayon cords 12, 12,. Are buried at intervals.

The reinforcing member 11 is provided at the side uneven portion A
Is attached to the inner surface of the tire with the axial direction of the rayon cords 12, 12,... Being oriented in the tire radial direction, and the tension of the ply cord 5 is reduced by the attachment. The reinforcing material 11, in particular, the rayon cords 12, 12... Is borne to reduce the tensile load on the ply cord 5, thereby suppressing the reduction in strength and the progress of fatigue. FIG. 4 shows the distribution state of the ply tension in each part of the radial tire 1 when the reinforcing material 11 is attached to the radial tire 1 and when it is not attached.

As can be understood from FIG.
When 1 is not stuck, the ply tension of the ply cord 5 is
Although the tension decreases linearly from the bead portion 3 toward the tread portion 9 and has a uniform tension at the tread portion 9, when the reinforcing material 11 is attached, the reinforcing material 11 is attached. In some parts, the ply tension of the ply cord 5 is reduced by the ply tension being borne by the reinforcing material 11. That is, by attaching the reinforcing material 11 to the side uneven portion A of the radial tire 1,
In the affixed portion (side uneven portion A), the ply tension is divided and shared between the ply cord 5 and the reinforcing material 11, and the load of the ply cord 5 on the ply tension is reduced. This is because the reinforcing material 11 is attached to the side uneven portion A of the radial tire 1 so that the side uneven portion A
It is understood that the reduction of the strength of the ply cord 5 and the progress of fatigue can be suppressed.

FIG. 5 shows the deformation behavior of the ply cord 5 when the radial tire 1 is loaded and when the reinforcing material 11 is not attached to the radial tire 1. FIG. The drawing is made by calculating the deformation amount of each part of the ply cord 5 in both cases.

As can be understood from FIG.
In the case where No. 1 is adhered, the deformed curvature radius R ₁ is larger than the deformed radius of curvature R ₂ when not adhered, so that the deformed curvature is small and the amount of deformation is small. ing. Reducing the amount of deformation by attaching the reinforcing material 11 means suppressing the reduction in strength and the progress of fatigue based on the aging of the ply cord 5.

FIG. 6 shows a result of a fatigue test of the ply cord 5, and shows a change with time (running distance) due to running when the reinforcing material 11 is stuck to the radial tire 1 and when it is not stuck. Each time, a hunter fatigue limit test was performed.

In both the case where the reinforcing material 11 is adhered and the case where the reinforcing material 11 is not adhered, the fatigue increases with the lapse of time (travel distance) due to running, but the degree of the fatigue varies. When the reinforcing material 11 is stuck, even if the running distance reaches 50,000 km,
In the case where the BU does not reach the BU generation area but the reinforcing material 11 is not stuck, the fatigue becomes less than 50,000 km within the traveling distance of 50,000 km.
It is understood that when the occurrence area is reached and the radial tire cannot be used and the reinforcing material 11 is adhered, fatigue is suppressed based on a temporal change (running distance) due to running.

FIG. 7 shows a strength test of the ply cord 5, in which the reinforcing material 11 is attached to the radial tire 1.
The strength reduction rate is calculated for each time-dependent change (running distance) due to running between the case of sticking and the case of not sticking.

In both the case where the reinforcing material 11 is adhered and the case where the reinforcing material 11 is not adhered, the strength decreases with the lapse of time (running distance) due to running, but there is a difference in the degree of the decrease. , With a mileage of 50,000 km,
There is a large difference in the rate of decrease in strength, and when the reinforcing material 11 is not attached, the strength is significantly reduced.

This means that even if the strength of the ply cord 5 is reduced due to a change with time due to running, the reduction in the strength of the ply cord 5 can be suppressed by attaching the reinforcing material 11. ing.

As described above, the method of repairing the side uneven portion of the radial tire according to one embodiment of the present invention has been described in detail. However, the present invention is not limited to the above-described embodiment, and is described in the claims of the present invention. Various changes in design may be made without departing from the spirit of the described invention. For example, in the above embodiment, the radial tire for trucks and buses has been described.
It can be applied to radial tires for other uses.

[0030]

As will be understood from the above description, the method for repairing the side irregularities of the pneumatic radial tire according to the present invention is based on
When unevenness occurs in the side portion, a reinforcing material is attached to the tire inner surface side of the side uneven portion, so that even if the radial tire is continuously used for a long time by running, the side The reduction in the strength of the ply cord at the uneven portion and the progress of fatigue are suppressed, and the tire can be used for a long time.

[Brief description of the drawings]

FIG. 1 is a cross-sectional perspective view of a pneumatic radial tire to which an embodiment of a method for repairing a side uneven portion of a radial tire according to the present invention is applied.

FIG. 2 is a cross-sectional view of the pneumatic radial tire of FIG.

FIG. 3 is a perspective view showing a reinforcing material attached to the pneumatic radial tire to which the embodiment of FIG. 1 is applied;

FIG. 4 is a view showing a ply tension distribution of a ply cord of the pneumatic radial tire of FIG. 1;

FIG. 5 is a view showing a deformation behavior of the ply cord of the pneumatic radial tire of FIG. 1 under a load.

FIG. 6 is a graph showing a relationship between a change over time (running distance) of a pneumatic radial tire having a side uneven portion and fatigue of a ply cord.

FIG. 7 is a graph showing a relationship between a change over time (running distance) of a pneumatic radial tire having a side uneven portion and a ply cord strength.

[Brief description of reference numerals]

 DESCRIPTION OF SYMBOLS 1 Pneumatic radial tire 2 Rubber layer 3 Bead part 4 Beat core 5 Ply cord 6 Carcass layer 7 Steel cord 8 Steel belt layer 9 Tread part 10 Rib groove 11 Reinforcement material 12 Rayon cord A Side irregularities

──────────────────────────────────────────────────の Continued on the front page (51) Int.Cl. ⁶ Identification code FI B29L 30:00

Claims (3)

[Claims] 1. A method for repairing a side uneven portion generated in a radial tire provided with a ply cord, wherein a reinforcing material is attached to an inner surface of the tire at the side uneven portion. 2. The radial tire repair method according to claim 1, wherein the reinforcing member is made of a patch-like rubber body and has a rayon cord embedded therein. 3. The radial tire repair method according to claim 2, wherein the reinforcing member is attached with the axial direction of the rayon cord directed to the tire radial direction.