JP3202783B2 - Manufacturing method for pneumatic tires - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for manufacturing a pneumatic tire, and more particularly to a method for manufacturing a high-performance pneumatic tire having excellent high-speed durability.

[0002]

2. Description of the Related Art Conventional high performance pneumatic tires include:
A belt made of a steel belt intersecting layer is arranged on the outer peripheral side of the radial carcass, and a plurality of heat-shrinkable organic fiber cords arranged in parallel with each other in a two-dimensional plane are completely disposed on the outer peripheral side of the belt. There is provided a belt auxiliary layer formed by continuously winding a belt-shaped ribbon made of rubber coating spirally. According to such a pneumatic tire, the belt end peeling is prevented under the action of the belt auxiliary layer. It is said that the tire can improve the high-speed durability of the tire.

[0003]

However, in the case of a pneumatic tire, a small amount of air generally remains between the tread rubber and the belt or the belt auxiliary layer when the tire is molded. Will remain as it is even after vulcanization of the tire, and when the vehicle is running at high speed, the thermally expanded residual air will exert a force on the tread rubber in the direction of peeling it off, as described above. However, even when the belt auxiliary layer is provided for the purpose of improving the high-speed durability of the tire, there is a problem that the presence of residual air becomes a hindrance factor of the high-speed durability.

[0004] This is because the lower surface of the tread rubber layer at the time of molding and pasting is a smooth surface, and the lower part of the coating rubber between the carcass ply and the belt layer, between the belt layer and the belt auxiliary layer, and the like. The surface unevenness caused by the cord embedded in the tire does not increase, which makes it difficult to disperse the interlayer residual air to be dispersed in the tire circumferential direction along the surface unevenness. In the case where the cord layer on the outer peripheral side can exert a sufficient resistance against the thermal expansion force of the residual air, the thermal expansion of the residual air between the tread rubber layer and the cord layer can be reduced. The reason for this is that the tread rubber layer cannot sufficiently compete with the tread rubber layer.

In order to further improve the high-speed durability of the tire, if necessary, when the ribbon is spirally wound so as to overlap in the width direction, the overlap of the ribbon may be reduced. Air remains on the step,
The residual air causes the separation of the tread rubber, and also causes the separation of the belt auxiliary layer made of the belt-shaped ribbon, and there is a problem that almost no improvement in high-speed durability can be expected.

[0006] The present invention has been made as a result of studying to solve such problems of the prior art, and an object of the present invention is to provide, in particular, a method of vulcanizing and curing an internal residual tire. By effectively absorbing and dispersing most or all of the air, air that can effectively prevent tread rubber peeling even at ultra-high-speed running or continuous high-speed running that can exceed 300 Km / h An object of the present invention is to provide a method for manufacturing a tire including a tire.

[0007]

According to the present invention, there is provided a carcass extending toroidally between bead cores, a belt comprising at least two interlaced belt layers disposed on the outer peripheral side of a crown portion of the carcass, In manufacturing a pneumatic tire having a belt auxiliary layer disposed on the outer peripheral side of the belt and covering the belt with at least a portion in the width direction of the belt, for example, heat shrinkage arranged in parallel with each other in a two-dimensional plane The belt auxiliary layer is formed by continuously spirally winding a belt-shaped ribbon formed by rubber-coating a plurality of conductive organic fiber cords together, and at least one or more of the belt-shaped ribbons are formed at at least one side end of the belt-shaped ribbon. A part of the heat-shrinkable organic fiber cord of the book is exposed.

Another method of the present invention is a method of continuously winding a strip-shaped ribbon made of a plurality of heat-shrinkable organic fiber cords collectively and rubber-coated so as to be overlapped in the width direction thereof and spirally. At the same time, for example, one or a plurality of pre-treated heat-shrinkable organic fiber cords are disposed in the overlapping step portion of the ribbon strip to form a belt auxiliary layer.

[0009]

According to the former method of the present invention, the multifilament of the heat-shrinkable organic fiber cord exposed at at least one side end of the belt-like ribbon preferably having a width of 5 to 30 mm is formed inside when the tire is molded. Air remaining in the
Absorbing and dispersing over the entire length of the cord, of course,
In particular, at the time of rubber flow when vulcanizing and curing the tire, since the residual air is further absorbed and dispersed,
After completely embedding the exposed cord in which the residual air has been sufficiently absorbed and dispersed by the vulcanization and curing in the rubber, even if the residual air may thermally expand, the tread rubber and / or the belt auxiliary layer may have The residual air can sufficiently prevent a local large force in the peeling direction from being received, and therefore, the high-speed durability of the tire can be effectively improved.

This is particularly remarkable when the heat-shrinkable organic fiber cord is exposed on both sides of the ribbon. Moreover, in this case, when the ribbon is wound spirally with the ribbon overlapped in the width direction, the air remaining in the overlapped step is also sufficiently absorbed and dispersed under the action of the exposed cord. Can be.

Further, in the latter method, the cords arranged in the overlapping step portions of the ribbon ribbon sufficiently absorb and disperse the residual air in the same manner as the above-described exposed cords.
This also effectively prevents peeling of the belt auxiliary layer and the tread rubber.

[0012]

Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 is a sectional view showing an embodiment of the present invention in a state of a green tire. In FIG. 1 (a), reference numeral 1 denotes a radial carcass composed of one cord ply, and 2 denotes a radial carcass 1. 3 shows a belt disposed on the outer peripheral side of a crown portion.

The belt 2 is formed by two belt layers 2a and 2b made of respective steel cords extending symmetrically with respect to each other at a relatively small angle, for example, 22 ° with respect to the tire circumferential direction. Belt
Further, a belt auxiliary layer 3 substantially in direct contact with the belt 2 is disposed so as to overlap the entire width of the belt 2 in this example.

By the way, the belt auxiliary layer 3 here
In a state in which a plurality of heat-shrinkable organic fiber cords, which can be, for example, a 1260 d / 2 nylon cord, are arranged in parallel with each other, the cords are put together as shown in FIG. 1 (b). A ribbon 3b having a width of preferably 5 to 30 mm, which is obtained by exposing a part of one cord 3a at one side end while coating with rubber.
Is continuously wound in a spiral shape. In addition, as shown in the figure, the strip-shaped ribbon 3b is not only spirally wound with its both end faces in contact with each other, but also, if necessary, with its side end faces separated from each other, or in the width direction. It can also be spirally wound with overlapping.

According to such a pneumatic tire, the exposed portion of the multifilament cord 3a removes air remaining between the belt auxiliary layer 3 and the tread rubber 4 during molding of the tire, in particular, vulcanization of the tire. Upon curing, as described above, it is sufficiently absorbed and dispersed over its entire length, and after vulcanization and curing, the exposed cord 3a is embedded in rubber while absorbing and dispersing the residual air. Even if the tread rubber 4 thermally expands, the tread rubber 4 is effectively prevented from being locally subjected to a large force in the peeling direction by the residual air, and the belt auxiliary layer 3 of the tread rubber 4 is effectively prevented.
Can be effectively prevented.

FIG. 2 is a cross-sectional view showing another example of the belt-shaped ribbon, in which a plurality of rubber-coated heat-shrinkable organic fiber cords 3a are vertically moved at one side end of the ribbon 3b. The heat-shrinkable organic fiber cords 3a are also exposed on a part of the strip-shaped ribbon 3b. Air can be sufficiently absorbed and dispersed.

FIG. 3 is a sectional view showing another embodiment of the present invention. In this example, a belt auxiliary layer 3 is provided on the outer peripheral side of the belt 2 so as to cover only the respective side end portions. The belt auxiliary layer 3 is clearly shown in FIG. 2 (b). In this manner, it is formed by spirally winding the strip-shaped ribbon 3b having the heat-shrinkable organic fiber cords 3a exposed at both end portions while overlapping in the width direction.

According to this embodiment, the exposed cords 3a are located at the respective overlapping steps of the strip ribbon 3b, and the residual air can be sufficiently absorbed and dispersed over the entire length of each of the exposed cords 3a. In addition, not only the separation of the tread rubber 4 but also the separation of the belt auxiliary layer 3 can be effectively prevented.

FIG. 4 is a cross-sectional view illustrating another method of the present invention, in which a belt auxiliary layer 3 covering the entire outer width of the belt 2 is provided on the outer peripheral side of the belt 2 and the belt auxiliary layer 3 is provided. Strip ribbon 3b contributing to the formation of Method 3
4A and 4B, the belt 2 is overlapped and wound at the portions corresponding to the respective side end portions and the central portion of the belt 2, and as shown in FIG. The code 5 is provided.

Here, in this example, each of the bare cords 5 provided at each overlapping stepped portion is, for example, a heat-shrinkable organic fiber cord 3a embedded in a strip ribbon 3b.
A cord obtained by subjecting a pre-treatment agent to a dipping treatment to a cord of the same kind or another textile cord can be used.

Therefore, according to this embodiment, by absorbing and dispersing the residual air with the bare cord 5, the same operation and effect as those of the above-described embodiments can be obtained, and the tread caused by the thermal expansion of the residual air can be obtained. Rubber and other components can be sufficiently prevented from peeling, and the high-speed durability of the tire can be greatly improved.

[Comparative Example] Hereinafter, a comparative test regarding the residual air amount between the inventive tire manufactured according to the inventive method and the conventional tire manufactured according to the conventional method will be described.

◎ Test tire ○ Invention tire 1 The size was 255/40 ZR 17, and the carcass was 1650 d / 2.
1. A tire having the same structure as that described with reference to FIG. 1 except that a radial carcass formed by two carcass plies made of rayon cords and a belt auxiliary layer is formed in two layers. Inventive Tire 2 In addition to forming the belt auxiliary layer over the entire width of the belt in accordance with the description of FIG. 3, that is, the entire belt auxiliary layer covering the entire width of the belt is formed by overlapping the belt-shaped ribbon in the width direction. A tire similar to Inventive Tire 1 except that the tire is formed by spirally winding continuously. O Inventive Tire 3 Tire similar to Inventive Tire 1 except that the belt auxiliary layer was formed as described with reference to FIG. O Conventional tire A tire similar to Inventive tire 1 except that the belt auxiliary layer was formed as shown in FIG.

◎ Test method and results Table 1 shows the drum speed and operation time under the conditions of air pressure 2.50 (kg / cm ² ), test load 500 (kgf), camber angle 2 °, test room temperature 22 ° C. ± 3 ° C. When the high-speed endurance test was performed by changing according to the conditions shown in
In contrast, the conventional tire broke down at 320 km / h (tread chunk-out), while it was able to complete the race up to / h. After such a high-speed endurance test, the tread rubber was peeled from the belt auxiliary layer over the entire crown portion and visually inspected for traces of residual air. However, in the conventional tire, 12 very small residual air marks were observed.

[0025] The small residual air has almost no problem in normal traveling at about 200 km / h,
If the running speed exceeds the maximum speed, the tread rubber 4 is peeled off and the high-speed durability of the tire is reduced.
There was the largest residual air mark of mm x 10 mm.

[Table 1]

[0026]

As is apparent from the above description, according to the present invention, it is possible to greatly improve the high-speed durability of the tire without sacrificing the productivity, cost and various performances of the tire. it can.

[Brief description of the drawings]

FIG. 1 is a sectional view showing an embodiment of the present invention.

FIG. 2 is a cross-sectional view illustrating another example of a belt-shaped ribbon.

FIG. 3 is a sectional view showing another embodiment of the present invention.

FIG. 4 is a sectional view showing still another embodiment of the present invention.

FIG. 5 is a sectional view showing a conventional example.

[Explanation of symbols]

 Reference Signs List 1 radial carcass 2 belt 2a, 2b belt layer 3 belt auxiliary layer 3a heat-shrinkable organic fiber cord 3b ribbon ribbon 4 tread rubber 5 cord

──────────────────────────────────────────────────続 き Continuation of the front page (56) References JP-A-62-203803 (JP, A) JP-A-2-296507 (JP, A) JP-A-62-290524 (JP, A) JP-A-2-203 28003 (JP, A) JP-A-64-36434 (JP, A) JP-A-63-98424 (JP, A) JP-A-4-355121 (JP, A) JP-A-62-241703 (JP, A) Japanese Utility Model Application No. 3-6921 (JP, U) Japanese Patent Publication No. 36-15638 (JP, B1) Japanese Patent Publication No. 35-13176 (JP, B1) (58) Fields surveyed (Int. Cl. ⁷ , DB name) B29D 30/00-30/72

Claims (2)

(57) [Claims] 1. A carcass, a belt disposed on an outer peripheral side of the carcass, and a carcass further disposed on an outer peripheral side of the belt,
In manufacturing a pneumatic tire having a belt auxiliary layer that covers the belt at least partially in the width direction, a belt-shaped ribbon formed by rubber coating a plurality of heat-shrinkable organic fiber cords in a spiral shape. Forming a belt auxiliary layer by continuous winding, and exposing a part of the heat-shrinkable organic fiber cord to an exposed state at at least one side end of the belt-shaped ribbon. . 2. A carcass, a belt disposed on an outer peripheral side of the carcass, and a carcass further disposed on an outer peripheral side of the belt,
In manufacturing a pneumatic tire having a belt auxiliary layer that covers the belt at least partially in the width direction, a plurality of heat-shrinkable organic fiber cords are collectively rubber-coated to form a belt-shaped ribbon. A method for manufacturing a pneumatic tire, wherein the belt auxiliary layer is formed by wrapping in a direction and spirally winding continuously, and arranging a bare cord at an overlapping step portion of the ribbon.