KR940009917B1 - Manufacturing method of air charging tire - Google Patents

Abstract

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Description

Manufacturing method of pneumatic tire

1 is a sectional view of a tire obtained by the present invention when the internal pressure is zero.

2 is a sectional view of the same withstand pressure charging.

3 is a cross-sectional view showing a set state of a mold.

4a, b, c are the process charts of the conventional example.

5 is an explanatory diagram of a tire obtained by a conventional example.

6 is a cross-sectional view of a mold set of an improved conventional example.

7 is an explanatory diagram of the tire.

* Explanation of symbols for main parts of the drawings

70: bead ring 71: side rubber

72: belt member 50: tread member

51: peripheral groove 60: mold

62: protruding bone 62: molding recess

The present invention relates to a method for easily and efficiently manufacturing a pneumatic radial tire with excellent high speed durability.

In general, the present invention relates to a method for easily and efficiently manufacturing air-injected radial tires used in passenger cars, trucks, buses, and the like.

In general, the outer contour of the tread portion and the belt structure in air-injected radial tires used in passenger cars, trucks, buses, and the like are almost common to ultra-high speed tires and general tires, for example, a tread has a plurality of circumferential grooves. And lateral grooves.

In addition, it is common for the cross-sectional outer contour of the tread composed of blocks and / or ribs to exist on a single arc, and for example, an unstretched belt using a reinforcement mainly composed of a high elastic cord such as a metal cord. Also in the belt layer, the cross sectional shape is disposed substantially parallel to the outer contour of the tread.

By the way, such an air injection radial tire is generally manufactured by the process shown to FIG. 4A-FIG.

That is, as shown in FIG. 4A, firstly, the cover 2 is wound on the cylindrical former 1.

Here, the cover 2 is a rubberized layer having a cord made of fibers such as polyester, polyamide, rayon and aromatic polyamide substantially coincident with the direction of rotation of the former 1 One ply of, as many as three plies as possible.

Next, a bead ring 3 is set on both sides of the former 1 and also in a concentric position, and after the bead filler 4 is disposed on the bead ring 3, Both ends of the coupler 2 are folded back toward the outer side in the axial direction and bent in the opposite side, and as shown in the drawing, the pair of side rubbers 5 is opened and bonded to both sides of the coupler 2 in the center.

Then, as shown in FIG. 4B, the bladder 6 is inflated into a toroidal shape by a bladder 6 to open between the two side rubbers 5 on the curler ply 2. The belt member 7 and the tread member 8 are sequentially adhered to the portion, and the green tire 10 as shown in FIG. 4C is obtained through stitching (9).

Adhesion between the belt member 7 and the tread member 8 in FIG. 4C shows a plurality of rubberized layers in which cords having high modulus of elasticity such as metal cords are arranged at a shallow angle with respect to the main direction. The belt member 7 and the tread member 8 are integrally formed by alternately stacking the tread member 8 thereon and alternately stacking the tread member 8 thereon. Either method of adhering them together and adhering to the crown portion of the chopper 2 is employed.

As the tread member 8, an object having a substantially trapezoidal shape having substantially a radial outer side as shown in FIG. 4B was used.

The tread member 8 is integrally formed of a tread rubber 8A excellent in abrasion resistance and a mini skirt 8B similar to the side rubber 5 disposed on both sides thereof, but a single tread rubber 8A unit It is also possible to form the tread member 8, and in this case, it is preferable to attach the front end portions of the side rubbers 5 so as to cover both sides of the tread member 8 with each other.

The green tire 10 thus formed is placed in a mold (not shown) having a protruding valley for forming a groove in the circumferential direction, and vulcanized and cured under high temperature and high pressure by a conventional method, as shown in FIG. A pneumatic radial tire having one shape can be obtained.

That is, the air injecting radial tire T shown in FIG. 5 is a projection line made of blocks and / or ribs parallel to the belt member 7 through the belt base 7 on the cover ply 2. A tread layer 8 having an 8C region is formed along the circumferential groove 8D.

However, when the air-injection radial tire obtained by the above-mentioned conventional method and air of predetermined internal pressure are filled, the tread outer contour is shown as a dashed line in FIG. 5, and there is a particular problem during low speed or normal operation. However, when traveling at a high speed of 200 to 300 km / h degrees, the tread outer contour is generally convex outward in the radial direction, and in this case, the center portion of the protruding region 8C composed of blocks and / or ribs, in particular, Due to its large volume, it is likely to exhibit a protrusion line similar to the chain line of FIG.

In this manner, when the central portion of the protrusion line region 8C swells in the tread outer contour, the ground pressure at the swelling portion is locally excessively increased, and the tension and compression of the protrusion line region 8C is repeated for each of the excess loads. As a result, the internal temperature of the tread rubber layer 8A rises, so that the tread rubber is decomposed, the rubber strength rapidly decreases, and it becomes impossible to endure the centrifugal force due to the high-speed rotation, and thus, the protruding line region made of blocks and / or ribs. There was a problem that a phenomenon called blow out in which (8C) fell off was likely to occur.

Therefore, Japanese Unexamined Patent Publication No. 1-130921 has already proposed a method for manufacturing a pneumatic tire.

That is, the prior art attaches a pair of bead rings and side rubbers extending between a bead ring and both bead rings on a cylindrical former, inflates them in a toroidal state, and then causes a belt member and a tread member to float on the crown of the cuff. Green tires are formed by attaching a cylindrical body in which the belt member and the tread member are bonded to each other in another process, or by vulcanizing the green tire in a mold. In the method for manufacturing a pneumatic injection tire having a circumferential groove in the circumferential direction of the tread, a protrusion for forming a circumferential groove of the mold 30 in the tread member 20 as shown in FIG. The ridge 21 extending in the circumferential direction is provided in advance at the position corresponding to the valley 31, and the image is raised in the mold 30. This is a technique for vulcanizing and curing after the protrusions 31 and the ridge 21 of the tread member 20 are precisely aligned.

The air injection radial tire obtained by this technique has a shape structure shown by the solid line in FIG. 7 after finishing molding.

In other words, the belt layer 40 has a valley corresponding to the circumferential groove 23 of the tread portion, and a waveform having the center corresponding position of the protruding line region 22 formed of blocks and / or ribs as a mountain. Indicates.

This is because the ridge 21 of the tread member 20 is pressed against the protruding bone of the mold 30 so that the corresponding portion of the circumferential groove 23 of the belt layer 40 is selectively recessed.

When the tire T is filled with predetermined pressure air or is driven at a high speed, the outer contour structure of the tread and the belt structure change as shown by the broken line in FIG.

That is, the belt layer 40 is subjected to tension by internal pressure, and becomes a straight line substantially parallel to the tread outer contour, while the outer surface of each protruding line section 22 swells outward in the radial direction relative to the central portion of both ends. Rises.

Therefore, the air injection radial tire having the above-described structure significantly improves the high-speed safety compared to the prior art because the ground pressure of the central portion of the protruding line region 22 is suppressed at the time of high-speed driving.

The manufacturing method according to the above-mentioned publications (FIGS. 6 and 7) has its own usefulness, but has the following problems.

Since the ridge 21 is alternately formed in the tread width direction of the tread member, the workability of the green tread member is deteriorated.

In flat tires for high-speed driving, the grounding pressure of the 1 / 4-shoulder portion becomes high due to the lifting at ultra high speed, and the heat generation of the block and / or ribs in this portion becomes high. It is easy to produce a tear phenomenon (flow out), and it is difficult to suppress the rupture of the 1/4 shoulder part by adjusting the gauge by the extrusion shape of the green tread member.

It is an object of the present invention to provide a technique for producing an air-injected tire excellent in high-speed durability by suppressing heat generation at the shoulder portion which is excellent in workability of the green tread member and at the highest ground pressure.

According to the present invention, after the pair of bead rings 70 and the bead ring 72 and the side rubbers 71 that extend between the two bead rings 70 are attached to each other on the cylindrical foamer 1, they are expanded in a toroidal shape. The cylindrical member in which the belt member 73 and the tread member 50 are sequentially adhered onto the crown portion of the cuff 72 or in which the belt member 73 and the tread member 50 are bonded to each other in the above-described process may be used. The green tire GT is molded by being set in the crown portion of the curler ply 72, and after this, the protruding bone 61 and the circumference for forming the circumferential grooves G _{1 to} G ₆ of the tire T are formed. The green tire in the mold 60 having the concave portion 62 between the protruding valleys 61 for forming ribs or blocks R ₁ to R ₇ between the grooves G _{1 to} G ₆ . GT) a peripheral groove in the main direction of curing by vulcanization, the tread (G ₁ ~G ₆₎ producing the air inlet having a Thai It is in the way, and takes the following technical means to attain the object described above.

That is, according to the present invention, the circumferential groove 51 of the cross-sectional V-shape with a gentle inclined surface is provided in advance in the loading portion of the 1/4 shoulder portion in the tread member 50, and the 1/4 shoulder portion is placed in the mold. Pneumatic tires obtained by vulcanizing and hardening the molding recess 62 and the circumferential groove 51 of the tread member 50 for forming rims or blocks R ₂ and R ₆ are internal pressure. Is 0, the belt member 73 and the focusing 72 are formed at the center of the ribs or blocks R _{2 and} R ₆ which are the circumferential grooves 51 of the cross-sectional V-shape in the tread member 50. Becomes convex as shown in FIG.

Then, when the internal pressure is filled, the belt member 73 and the cover 72 will be in a straight state, so that the surfaces of the ribs or blocks R ₂ and R ₆ are recessed 75A as shown in FIG. This can reduce heat generation and suppress rupture, thereby improving high speed durability.

Hereinafter, embodiments of the present invention will be described in detail.

In the present invention, the pre-grooved tread member 50 is pre-installed with a circumferential groove 51 having a cross-section V-shaped with a gentle inclination angle in the extruded green tread member 50 and a portion corresponding to the 1/4 shoulder portion. Until the tire GT is formed, it is the same as the conventional example described with reference to the fourth, a, b, and c drawings, and accordingly, the reference numerals of the corresponding tire constituent members are shown in the fourth a, b, c diagrams. In the present invention, a cap ply 74 is added on the belt member 73.

3, the mold 60 has protrusions 61 for forming the circumferential grooves G _{1 to} G ₆ of the tire, and blocks or ribs R _{1 to} R ₇ between the protrusions 61. ) and the molding has a recess (62) for forming, W _T is a width of a tread mold, W is W _T / 2, and symmetrical to the boundary of the tread center line 0-0. Here, the groove bottom of the circumferential groove 51 is precisely aligned so as to coincide with the center of the blocks R _{2 and} R ₆ , that is, the center of the molding recess 62, but the circumferential groove 51 is shown in FIG. 3. It is as follows.

However, Wc-Wb≥5.0mm

That is, according to the present invention, the pair of bead rings 70 and the bead ring 72 and the side rubbers 71 that extend between the two bead rings 70 are bonded to each other on the cylindrical former 1 and then expanded in a toroidal shape. After that, the belt member 73 and the tread member 50 are sequentially adhered to the crown portion of the cuff 72, or in another process, the cylindrical body which adheres the belt member 73 and the tread member 50 to each other. The green tire GT is formed by setting the tire to the crown portion of the cuff 72, and thereafter, ribs or blocks R _{1 to} R are formed between the circumferential grooves G _{1 to} G ₆ of the tire T. ₍₇ ) by vulcanizing the green tire (GT) in the mold (60) having a molded concave portion (62) between the protruding bones 61 for forming a circumferential groove (G ₁ ~) a method for manufacturing the air injection Thai having a G _6), 1/4 of the tread member 50 Installing in advance a V-shaped cross-section jugu 51 by a more gentle slope part only of the loading part, the mold 60, the rim of a quarter or a shoulder portion in the block (R _2, R ₆₎ for the formation higi This is to vulcanize and harden the molding recess 62 and the circumferential groove 51 of the tread member 50. As a result, when the internal pressure is 0, a 1/4 shoulder portion, that is, as shown in FIG. in the portion of the peripheral corresponding to the groove 51, a block (R _2, R _6), the belt member 73, keoeo carcass ply 72 and cap ply 74 includes a raised portion (75 continuous to the main direction in the central portion of the ), and is in, if the charging internal pressure as shown standing in the second road to the tire (T), because about to the belt member 73, keoeo carcass ply 72 and cap ply 74 is straight state block (R _{2 ,} R ₆₎ of the surface is a recess (75A), such as rupture caused by the highest heat in the high-speed driving by this Will be suppressed.

In this regard, in Figs. 1 and 2, in the high-speed drum test with four cams, the heat generation becomes R6 > R5 > R7 > R4 > R1 > R3 > R2. The ribs or blocks of R _{2 and} R ₆ generate the greatest heat.

Next, a test result in which the tire by the so-called trapezoidal tread member shown in Fig. 4 is A, the tire according to Japanese Patent Laid-Open No. 1-13095 is B, and the tire according to the present invention is C is as follows.

[test requirements]

Tire size: 205 / 55R 15 88V

Rim: 5 ′ / 2J × 5

Inner pressure: 3.05kg / cm²

Load: 403kg f (ETRTO SID × 0.74)

Cabber angle: 4 °

Drum Diameter: 1.7m

Driving staff: speed 240km / h 250km / h… → time 60 minutes → 10 minutes →. → 10km / h up every 10 minutes

[Test result]

The present invention is as described above, the heat generation of the shoulder portion that generates the most heat during high-speed driving can be reduced, the burst can be suppressed, the high-speed durability improvement is remarkable, and the workability of the green tread member is also easy to reduce the production cost Can be.

Claims (1)

After the pair of bead rings 70 and the coupler 72 and the side rubbers 71 that extend between the two bead rings 70 are bonded to each other on the cylindrical former 1, and then inflated to a toroidal shape, the belt member ( 73) or the tread member 50 is sequentially adhered to the crown portion of the cuff 72, or in a different process the cylindrical body to which the belt member 73 and the tread member 50 are bonded to each other The green tire GT is molded by being set in the crown portion of the 72, and after this, the protruding bone 61 and the circumferential groove G for forming the circumferential grooves G _{1 to} G ₆ of the tire T are formed. The green tire GT is formed in the mold 60 having the concave portion 62 between the protruding bones 61 for forming ribs or blocks R _1- R ₇ between _{1 to} G ₆ . By vulcanizing, the method of manufacturing an air injection tire provided with circumferential grooves G _{1 to} G ₆ in the circumferential direction of the tread. In the tread member 50, a circumferential groove 51 having a cross-sectional V-shape with a gentle inclined surface is provided in advance in the insertion portion of the 1/4 shoulder portion, and the 1/4 shoulder in the mold 60 is provided. Pneumatic injection tire characterized in that the vulcanization hardening after precisely matching the molding recess 62 and the circumferential groove 51 of the tread member 50 for forming the rim or block (R _2, R ₆ ) of the portion Manufacturing method.