JPH1159129A - High speed and heavy load retreaded tire - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a durable retreaded tire in which retreadability is improved in retreading the tire without giving damage to the cords in the outermost layer of the crown part of a carcass main body of the tire. SOLUTION: In a retreaded tire on which a new tread rubber is stuck, a reinforced fabric layer comprising at least one layer of rubber coated cords is arranged adjacent to the outside of the crown part of the tire. Also the thickness S of the rubber layer formed between the cords in the innermost layer 1 of the reinforced fabric layer and the cords in the outermost layer of the crown part of the carcass main body of the tire is 0.8 to 2.3 times the diameter of the cards D in the innermost layer of the reinforced fabric layer, and the thickness (t) of the coated rubber layer on the outside of the cords in the innermost layer of the reinforced fabric layer is smaller than the thickness of the rubber layer formed between the cords in the innermost layer of the reinforced fabric layer and the cords in the outermost layer of the crown part of the carcass main body of the tire.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a pneumatic retread tire, and more particularly to a high-speed heavy-load retread tire represented by an aircraft retread tire.

[0002]

2. Description of the Related Art Conventionally, aircraft tires have a problem in that when a predetermined amount of tread rubber is worn, the remaining aged tread rubber remains.
Rubber and other materials are buffed and removed from the tires, producing so-called retread tire base tires, which have been newly reused as retread tires with new tread rubber, reinforcing fabric layers and cushion rubber attached. . When retreaded tires are used and the tread rubber is worn by a predetermined amount, the remaining tread rubber
Rubber and the like are buffed and removed from the tires, and new tread and rubber are attached and reused repeatedly. Typically, aircraft tires are retreaded and reused at least five or six times. When the tire is rehabilitated, the tread rubber, the reinforcing fabric layer and the cushion rubber are removed from the used tire as described above, and the carcass body is left as the base tire. The carcass body includes bead cores, carcass plies, and side rubber layers on the left and right, a breaker for a bias tire having a breaker, and a belt layer for a radial tire. In the present specification, the `` carcass body of the base tire '' includes a bead core, a carcass ply, and a side rubber layer, a breaker for a bias tire having a breaker, and a belt layer for a radial tire. Therefore, the `` cord of the crown outermost layer of the carcass body of the base tire '' refers to the cord of the outermost layer of the belt layer for radial tires, and refers to the cord of the outermost layer of the breaker for bias tires having breakers. In the case of a bias tire without a breaker, it refers to the cord of the outermost layer of the carcass ply.

[0003]

Since the cushion rubber is a wide sheet having a thickness of about 0.5 mm, wrinkles are easily generated when the cushion rubber is stuck on a base tire. Among these, the sheet attaching process was a process with extremely poor workability. Therefore, in the retreaded tire of the present invention, the use of the cushion rubber is stopped to improve the retreadability. However, if the cushion rubber is simply abolished, naturally, the thickness of the rubber layer inside the reinforcing fabric layer becomes thinner. The outermost layer cord may be damaged. On the other hand, when the thickness of the rubber layer inside the reinforcing fabric layer is increased, a heat separation failure is likely to occur, and thus the durability of the retreaded tire is reduced.

[0004] It is an object of the present invention to provide a retread tire having improved durability when retreading the tire without damaging the cord of the outermost layer of the crown portion of the carcass body of the base tire and having excellent durability. is there.

[0005]

In order to achieve the above-mentioned object, a retreaded tire according to the present invention is newly added to a base tire in which old tread rubber or the like remaining from used tires is removed by buffing. In a retread tire to which tread rubber is attached, (1) a reinforcing fabric layer comprising at least one rubber-coated cord layer is disposed adjacent to the outside of a crown portion of the base tire, and (2) the reinforcing fabric (3) the innermost layer of the reinforcing fabric layer has a thickness T of 0.8 to 2.3 times the cord diameter D of the innermost layer of the reinforcing fabric layer; The thickness t of the outer coating rubber layer of the cord is smaller than the thickness T of the inner coating rubber layer.

Conventionally, a tread rubber, a reinforcing fabric layer, and a cushion rubber have been attached to a base tire to manufacture a retreaded tire. As described above, wrinkles occur when the cushion rubber is attached to the base tire. The sheet sticking step is a process that is extremely poor in workability even in the process of manufacturing a retreaded tire.

In the retreaded tire of the present invention, the use of the cushion rubber is stopped to improve the retreadability. As described above, the crown rubber of the base tire is located at the position where the cushion rubber is conventionally disposed. Adjacent to the outside is a reinforcing fabric layer comprising at least one rubber-coated cord layer. The thickness T of the rubber coating layer inside the innermost cord of the reinforcing fabric layer is 0.8 to 2.3 times the cord diameter D of the innermost layer of the reinforcing fabric layer. When the thickness of the rubber layer is smaller than 0.8 times the cord diameter of the innermost layer of the reinforcing fabric layer, the cord of the outermost layer of the crown portion of the carcass body of the base tire will be replaced at the next buffing operation of the tire rehabilitation. May hurt. On the other hand, if the thickness of the rubber layer is greater than 2.3 times the cord diameter of the innermost layer of the reinforcing fabric layer, a heat separation failure is likely to occur, and thus the durability of the retreaded tire is reduced.

In the retread tire of the present invention, as described above,
It is necessary that the thickness t of the outer coating rubber layer of the innermost cord of the reinforcing fabric layer is smaller than the thickness T of the inner coating rubber layer. This is because if the thickness t of the outer coating rubber layer of the cord of the innermost layer of the reinforcing fabric layer is larger than the thickness T of the inner coating rubber layer, a heat separation failure is likely to occur, and therefore the durability of the retreaded tire is increased. This is because the property is reduced.

In the retread tire according to the present invention, as described above, the thickness of the innermost cord-coated rubber layer of the reinforcing fabric layer is different between the inside and the outside, and the thickness of the inside rubber layer is the thickness of the outside rubber layer. Larger is preferred to prevent heat separation failure.

[0010]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, a tire according to an embodiment of the present invention and a tire according to a comparative example will be described with reference to the drawings. In each case, the tread rubber is worn by a predetermined amount and the old tread rubber remaining on the pneumatic bias tire for aircraft whose first life has expired is buffed off and the reinforcing fabric layer and the tread rubber are newly added. This is a rehabilitated retreaded tire with a tire size of H49
× 19.0-22 32PR.

FIG. 1 is a partial sectional view of the innermost layer of the reinforcing fabric layer of the tire of the embodiment and the outermost layer of the crown portion of the carcass body of the base tire. In the tire of the embodiment, the tread rubber is worn by a predetermined amount, the old tread rubber remaining in the pneumatic bias tire for aircraft which has finished the first life is buffed and removed, and a new reinforcing fabric layer and A retreaded tire in which tread rubber is replaced, wherein a reinforcing fabric layer comprising a rubber-coated cord layer is disposed adjacent to the outside of a crown portion of a base tire, and the inside of a cord of an innermost layer 1 of the reinforcing fabric layer. The thickness T = 0.75 mm of the covering rubber layer is 1.47 times the cord diameter D = 0.51 mm of the innermost layer of the reinforcing fabric layer, and the outer covering rubber layer of the cord of the innermost layer 1 of the reinforcing fabric layer. Is smaller than the thickness T of the inner coating rubber layer.

The tire of the comparative example has a thickness T = 0.2 of the covering rubber layer inside the cord of the innermost layer 1 of the reinforcing fabric layer.
5 mm is the cord diameter D of the innermost layer of the reinforcing fabric layer =
It is 0.49 times of 0.51 mm, and the thickness t = 0.0 of the coating rubber layer outside the cord of the innermost layer 1 of the reinforcing fabric layer.
It is almost the same as the tire of the above embodiment, except that 25 mm is the same as the thickness T of the inner covering rubber layer.

Next, comparative tests were performed on the tires of these examples and the comparative example. In the results of the comparative test,
In the tire of Example, no cord exposure occurred in the carcass of the base tire at the time of buffing, but in the tire of Comparative Example, cord exposure occurred in about 15% of the entire buff surface.

The results of the above comparative tests are shown in Table 1 together with the outlines of the tires of the examples and the comparative examples.

[0015]

[Table 1]

[0016]

From the results of the comparative test shown in Table 1, it can be seen that the tire of the example is an excellent tire in which the carcass cord exposure of the base tire does not occur during buffing as compared with the tire of the comparative example.

[Brief description of the drawings]

FIG. 1 is a partial cross-sectional view of a reinforcing fabric layer and a carcass of a base tire.

[Explanation of symbols]

 1 Innermost layer of reinforcing fabric layer 2 Outermost layer of crown portion of carcass body of two tires D Code diameter S Thickness of rubber layer t Thickness of outer coating rubber layer T Thickness of inner coating rubber layer

Claims (1)

[Claims] 1. A retreaded tire in which tread rubber is newly attached to a base tire from which old tread rubber or the like remaining from used tires has been buffed and removed, and (1) a crown of the base tire A reinforcing fabric layer comprising at least one rubber-coated cord layer is disposed adjacent to the outer side, and (2) the thickness T of the coating rubber layer inside the innermost cord of the reinforcing fabric layer is such that 0.8 to 2.3 times the cord diameter D of the innermost layer of the reinforcing fabric layer, and (3) the thickness t of the outer covering rubber layer of the innermost cord of the reinforcing fabric layer is smaller than that of the inner covering rubber layer. A high-speed heavy-load retreaded tire having a thickness smaller than T.