JPH0811237A - Method of manufacturing tire and stitching apparatus used in the same - Google Patents

Abstract

PURPOSE:To provide a method of manufacturing a tire with excellent uniformity and a stitching apparatus employed in the same. CONSTITUTION:In the tread forming part 5 of a tire base body 2 having a carcass ply 10 that extends from the tread forming part 5 via the side wall parts 6 and then is tuned back around the bead core 9, when the tread forming part 5 expands out toward the outside of the radial direction and thus the tire base body 2 deforms in a toroidal shape, a raw cover 4 is formed which has an angular tread cover ring 3 mounted thereon having a belt ply 11 in the inner face side and also having a tread rubber 12 disposed in Its outer face side. In this manner, the outer peripheral face of the tread rubber 12 of the raw cover 14 being charged with inner pressure is pressed in its static condition by means of a pair of rollers located left and right across the tire equator C and runs round in different direction each other in the tire peripheral direction, thus a manufacture of tire containing a stitching process is achieved by placing the tire base body 2 and tread ring 3 into close contact with each other.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a tire manufacturing method capable of providing a tire excellent in uniformity and a stitching device used for the method.

[0002]

2. Description of the Related Art In a tire manufacturing process, particularly a pneumatic radial tire molding process, as shown in FIG.
At the tread forming portion a of the tire base body f having the carcass ply e folded back around the bead core d of the bead portion c from the tread forming portion a to the sidewall portion b, the belt ply i is provided on the inner surface side. And a ring-shaped tread ring g having a tread rubber j on the outer surface thereof is bonded to form a raw tire cover h of the tire.

Prior to vulcanization, the green cover h is obtained by airtightly attaching the bead portion c to the clamp ring k, filling a predetermined internal pressure, and then pressing the roller bodies m and n against the tread rubber j. A so-called stitching step is performed in which the tire base f and the tread ring g are brought into close contact with each other.

In this stitching process, as shown in FIGS. 5 and 6, the clamp ring k having the raw cover h mounted thereon is rotated at a relatively high speed, and a pair of right and left roller bodies m and n are sandwiched across the tire equator. Are moved in the axial direction from the tread crown portion toward the tread shoulder portion while being brought into contact with each other.

[0005]

However, when the state of the belt cords of the belt ply i is examined after the above-mentioned stitching process is performed, as shown in FIG. It was found that the kinks of the squirrel occurred. When the original arrangement angle is θ1, the twist of the belt cord p is an arrangement angle θ2 larger than the angle θ1 at the right end of the ply, and an arrangement angle θ3 smaller than θ1 at the left end of the ply.
Different belt cord arrangement angles are generated at the left and right ends of the belt ply i.

This means that the non-uniformity remains in the finished tire after vulcanization, and conicity force (hereinafter referred to as "CON") is generated in a certain direction regardless of the tire rotating direction, and the tire rotating shaft. Radial force variation (hereinafter referred to as "RF
V ”. ) And lateral force variation (hereinafter referred to as “LF
V ”. ) Will cause an abnormal force that you do not want to occur.

As a result of earnest studies in view of such problems, the inventor of the present invention is completely different from the conventional process in which a raw cover is rotated and brought into contact with a roller body having a fixed rotating shaft for stitching. Based on the idea, with the raw cover still, the pair of left and right roller bodies sandwiching the tire equator are lapped in different directions in the tire circumferential direction for stitching, and the belt cord of the belt ply is basically used. Array angle is different at both ends of ply,
The inventors have completed the present invention by discovering that such non-uniformity on the left and right can be eliminated.

[0008] That is, the present invention is a method of manufacturing a tire which can prevent the end portions of the belt cords of the belt ply from having cord arrangement angles different from each other at both ends of the ply, thereby providing a tire excellent in uniformity. It is an object of the present invention to provide a stitching device used for this purpose.

[0009]

According to the first aspect of the present invention,
In the tread forming portion of the tire base body including the carcass ply that folds around the bead core of the bead portion from the tread forming portion to the sidewall portion, the tread forming portion bulges outward in the radial direction and the tire base body becomes toroidal. When deforming, a belt ply is provided on the inner surface side and an outer surface side is provided with an annular tread ring on which a tread rubber is arranged to form a green cover, and a method for manufacturing a tire in which this green cover is vulcanized, Prior to vulcanization, the outer surface of the tread rubber of the raw cover filled with internal pressure is in a stationary state of the raw cover, a pair of left and right with the tire equator interposed, and pressed by roller bodies that circulate in different directions in the tire circumferential direction, A tire manufacturing method including a stitching step of bringing the tire base and the tread ring into close contact with each other.

According to a second aspect of the present invention, the belt ply is provided on the inner surface side of the tread forming portion of the tire base body having the carcass ply that is folded back from the tread forming portion to the sidewall portion around the bead core of the bead portion. Having a raw cover equipped with an annular tread ring having a tread rubber on the outer surface side, a support device that supports the stationary by filling the internal pressure, a pair of left and right across the tire equator, and mutually in the tire circumferential direction. A stitching device comprising a stitcher having roller bodies that orbit in different directions.

[0011]

According to the method of manufacturing a tire of the present invention, in the stitching step, the raw cover is kept stationary and a pair of left and right sides are sandwiched by the tire equator on the outer peripheral surface of the tread rubber, and the tire covers are oriented in different directions in the tire circumferential direction. As a result of pressing the revolving roller body, the belt cords at the left and right ends of the belt ply are both acted upon by a common force to either reduce or increase the cord angle, thereby arranging the arrangement angles between the two ends of the belt ply. The non-uniformity can be eliminated, and the uniformity of the finished tire after vulcanization is improved.

According to another aspect of the stitching device of the present invention, a pair of left and right sides sandwiching the tire equator are provided on the outer peripheral surface of the tread rubber of the raw cover held stationary by the supporting device, and are different from each other in the tire circumferential direction. By providing a stitcher that can press the roller body that circulates in the direction, the belt cords at the left and right ends of the belt ply are both subjected to a common force that either reduces or increases the cord angle, and The nonuniformity of the arrangement angle between the two ends of the belt ply can be removed in the step of forming.

In the roller body, the dimension of the pressing surface for pressing the tread rubber in the tire axial direction is 1 / the width of the tread.
When it is smaller than 2, the roller body is preferably movable in the tire axial direction. Further, a plurality of roller bodies are provided, and the rollers adjacent to each other around the tire rotation axis in the tire circumferential direction have an equal angle. It is preferable to dispose in order that the raw cover will not be twisted.

[0014]

DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described below with reference to the drawings. The method of manufacturing a tire according to claim 1, wherein the raw cover 4 of the tire in which the annular tread ring 3 is mounted on the tire base 2 having a toroidal shape is filled with internal pressure, and the outer peripheral surface of the tread rubber 12 of the raw cover 4 is filled. The roller bodies 13 that rotate in a pair in the left-right direction and in different directions in the tire circumferential direction across the tire equator when the raw cover 4 is stationary.
The tire manufacturing process includes a stitching process in which the tire base 2 and the tread ring 3 are pressed into close contact with each other by being pressed by A and 13B.

The tire base 2 is provided with a carcass ply 10 which is folded back from the tread forming portion 5 to the side wall portion 6 to which the side wall rubber is attached and folded back around the bead core 9 of the bead portion 7, and the tread forming portion 5 has a radius. The tread ring 3 can be mounted when the tire base body 2 bulges outward in the direction and deforms into a toroidal shape.

The tread ring 3 is a belt made of plies in which belt cords made of an organic fiber material or steel are arranged on the inner surface side in rubber at an angle θ1 of about 50 ° to 90 ° with respect to the radial direction of the tire. In the present example, two plies 11 are arranged in an overlapping manner, and a tread rubber 12 is arranged on the outer surface side of the annular body.

The raw cover 4 is filled with a predetermined internal pressure to bring the tread forming portion 5 of the tire base 2 and the tread ring 3 into close contact with each other, and in addition to this, the outer peripheral surface of the tread rubber of the raw tire 4. In the stationary state of the raw cover, as shown in FIG. 3, a stitching process is performed in which a pair of rollers 13A and 13B that circulate in different directions in the tire circumferential direction sandwich the tire equator C and rotate in different directions in the tire circumferential direction.

By performing such a stitching process, the tread forming portion 5 of the tire base 2 and the tread ring 3 can be brought into closer contact with each other more reliably, the adhesion between the two is improved, and the green cover 4 is molded. Can be good.

In addition, the roller bodies 13A, 13B provided in a pair on the left and right with the tire equator C sandwiching the tire equator C orbit the outer peripheral surface of the tread rubber 12 in different directions.
To the left and right ends of the belt ply 11 located on the inner side of the tread rubber 12 in the radial direction of the tire, it is possible to reduce or increase the cord angle with each other and to apply a common force to either one of them. Angle non-uniformity can be eliminated.

Incidentally, the roller body 1 of this embodiment shown in FIG.
With respect to the outer belt ply 11A located on the outer side in the tire radial direction in the circumferential direction of 3A and 13B, when the original belt cord angle is θ1, the cord angles θ3 at both ends of the ply are reduced from each other than θ1. The power of direction is given. Also, the belt ply 1 inside the tire radial direction
1B, the cord angle θ4 at both ends of the ply is
A force in the direction of increasing as compared with 1 acts.

When the number of the belt plies 11 is one, it is desirable that the left and right roller bodies 13A and 13B are rotated in the respective circulation directions along the belt cords. For example, only the belt plies 11B shown in FIG. In such cases, the direction of rotation is as shown in the figure. On the other hand, if one sheet of belt ply has a belt cord such as 11A, the left and right roller bodies 13A and 13B are rotated in the opposite direction to the above, because the cord is not excessively twisted. preferable.

Further, as in this embodiment, two belt plies 11A and 11B having belt cords crossing each other are used.
In this case, the roller bodies 13A and 13B need only be rotated in different directions, and the direction of each roller does not matter, but more preferably, the belt cord of the belt ply 11B within the wide belt ply width is used. It is desirable to follow the flow. The raw cover that has undergone the above stitching process is vulcanized to complete a tire.

As a stitching device for carrying out the stitching process, as shown in FIG. 1, a pair of left and right sides sandwiching the tire equator C and a supporting device 14 capable of supporting the raw cover 4 in an internal state by filling it with internal pressure, and as shown in FIG. An example is a stitcher 15 having roller bodies 13A and 13B that rotate in different directions in the tire circumferential direction.

The supporting device 14 includes a fixed shaft 16 having a hollow shape.
Clamp ring body 19 fixed to the joint via connecting pipe 17
Equipped.

The fixed shaft 16 extends to the left in the figure,
In addition, it is cantilevered and fixed to the ground, one end of which is connected to a high pressure air source, and the air supplied from this high pressure air source can be filled into the inner cavity of the raw cover 4 through the guide hole 20.

The clamp ring body 19 has an annular shape and is provided with a pair of holding portions 21 and 21 at both ends thereof for holding the bead portion 7 of the raw cover 4.

In the present embodiment, the holding portion 21 has a claw portion 22 at the upper end which rises outward in the radial direction of the clamp ring body.
And a tightening ring 24 fixed to the rising piece 23 by a screw means or the like and capable of sandwiching the bead portion 7 of the raw cover 4 with the claw portion 22,
Although the raw cover 4 can be held stationary while preventing leakage of air filled in the raw cover, the present invention is not limited to this, and only the inside of the tire as described in FIG. 5 is shown. Various materials such as those supported by the inner pressure of the supporting tire can be used.

In the present embodiment, the stitcher 15 has a rotating portion 2 rotatably held via a bearing on a pivot 26 fixed on the same axis as the fixed shaft 16 of the supporting device 14.
7 and the rotating portion 27, which is supported by the tip of a protruding shaft 29 that is provided to project toward the raw cover 4 side supported by the support device 14 and comes into pressure contact with the outer peripheral surface of the tread rubber 12 of the raw cover 4. And a roller body 13. The pivot shaft 26 of the stitcher 15 on the left side in the drawing also serves as the fixed shaft 16.

In this embodiment, the rotating portion 27 has a sprocket 30 fixed to one end thereof and a rotary base cylinder 31 which is decelerated and rotated by a motor (not shown). The rotary base cylinder 31 is fixed to the rotary base cylinder 31. And a moving frame 33 that can move in the axial direction by a cylinder 32. The moving frame 33 is
The rotary base cylinder 31 rotates integrally with the rotary base cylinder 31 and is allowed to move only in the axial direction with respect to the rotary base cylinder 31 via a linear motion bearing or the like.

Therefore, the roller body 13 is the rotary base cylinder 3
1 can be rotated around the tread rubber outer peripheral surface of the raw cover 4 by being driven by a motor or the like, and can be moved in the tire axial direction by contracting the rod of the cylinder 32. Therefore, the tread rubber outer peripheral surface can be spirally rotated. It is possible to do.

It is desirable that at least one roller body 13 is provided on each of the left and right sides, preferably two or more rollers, and three or four rollers are provided on each of the left and right sides as shown in FIGS. In this way, for example, by setting the number of each of the left and right roller bodies 13 to three as shown in FIG. 3, the moving amount in the tire axial direction per one rotation of the rotating portion 27 can be made larger than that of one roller body. It can be tripled and the stitching process time can be shortened.

Further, as shown in FIG. 4, each roller body 13
Are arranged in a line-symmetrical manner with the axis center of the pivot shaft 26 as a center of symmetry in a side view, to prevent the raw cover 4 from twisting about an axis line in a direction perpendicular to the tire rotation axis, and the raw cover 4 is accurately adjusted. It is more preferable because it can be molded well.

Further, when a plurality of roller bodies are provided, the contact surface between the rollers and the raw cover increases, so that the internal pressure to be filled in the raw cover 4 can be reduced.
As a result, large deformation of the belt cord of the belt ply can be prevented as much as possible.

(Specific example) Tire size is 185 / 70R
Fourteen radial tires were prototyped according to the invention of claim 1 (Example). The stitching process is as shown in FIGS.
The stitching device shown in FIG. Radial tires of the same size were also manufactured by the conventional manufacturing method (conventional example), and these were subjected to force variation (F
V) RFV, LFV, and CON were measured using a tester, and the respective measured values were displayed together with the variation (σ) thereof.

[0035]

[Table 1]

As a result of the test, it was confirmed that the tires of the examples had less RFV, LFV, and CON than the tires of the conventional example, and their variations were small, and were excellent in uniformity.

Although described in detail above, the inventions described in claims 1 and 2 are not limited to the above-mentioned embodiment, and particularly, in the stitching device described in claim 2, the roller width of the roller body is approximately the tread width. The roller body is automatically moved in the axial direction in accordance with the number of revolutions of the rotating portion by increasing the size to 1/2 and using the projecting shaft 29 as a screw shaft and using a ball screw nut for the roller body 13. Further, it can be deformed into various forms such as the one for moving the roller body 13 in the tire radial direction in accordance with the radius of curvature of the tread.

[0038]

As described above, in the tire manufacturing method according to the first aspect of the present invention, the belt cords at the left and right ends of the belt ply are subjected to a common force of reducing or increasing the cord angle. The nonuniformity of the arrangement angle between the two ends of the belt ply can be eliminated, and the uniformity of the tire after completion is improved.

In the stitching device according to the second aspect of the invention, the cords at the left and right ends of the belt ply are subjected to a common force such as reducing or increasing the cord angle, thereby arranging the cords between the ends of the belt ply. It is possible to perform a stitching process that can eliminate non-uniformity of angles and improve the uniformity of the finished tire.

[Brief description of drawings]

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

FIG. 2 is a conceptual diagram for explaining the arrangement of roller bodies.

FIG. 3 is a diagram showing a modification of a belt cord of a belt ply.

FIG. 4 is a conceptual diagram for explaining another arrangement of roller bodies.

FIG. 5 is a conceptual diagram for explaining a conventional stitching process.

FIG. 6 is a perspective view for explaining a conventional stitching process.

FIG. 7 is a diagram showing a modification of a belt cord of a belt ply by a conventional stitching process.

[Explanation of symbols]

 2 Tire Base 3 Tread Ring 4 Raw Cover 5 Tread Forming Part 6 Sidewall Part 7 Bead Part 9 Bead Core 10 Carcass Ply 11 Belt Ply 12 Tread Rubber 13 Roller Body 14 Supporting Device 15 Stitcher

Claims (4)

[Claims] 1. A tire base body having a carcass ply that folds around a bead core of a bead portion from a tread forming portion to a side wall portion, and the tread forming portion bulges radially outward in the tread forming portion. A method for manufacturing a tire in which, when the base body is deformed into a toroidal shape, an annular tread ring having a belt ply on the inner surface side and a tread rubber on the outer surface side is attached to form a green cover and the green cover is vulcanized In the stationary state of the raw cover, the outer surface of the tread rubber of the raw cover that has been filled with internal pressure prior to vulcanization has a pair of left and right with the tire equator sandwiched, and a roller body that orbits in different directions in the tire circumferential direction. A tire including a stitching step of pressing the tire base and the tread ring in intimate contact with each other. Manufacturing method. 2. A tire base body having a carcass ply which folds around a bead core of a bead portion from a tread forming portion to a sidewall portion, and has a belt ply on an inner surface side and an outer surface side on a tread forming portion. A support device that supports a raw cover equipped with a rubber-shaped annular tread ring by filling it with internal pressure and stationary, and a roller body that circulates in a pair of left and right across the tire equator and in different directions in the tire circumferential direction. A stitching device comprising a stitcher having a. 3. The stitching device according to claim 2, wherein the roller body is movable in the tire axial direction. 4. A pair of the left and right roller bodies are arranged on the outer peripheral surface of the tread rubber of the raw cover, and the angles between the rollers adjacent to each other around the rotation axis of the raw cover are substantially equal. The stitching device according to claim 2 or 3, wherein