JP7096091B2 - Manufacturing method and equipment for pneumatic tires - Google Patents

Description

The present invention relates to a method and an apparatus for manufacturing a pneumatic tire.

Conventionally, as a method for manufacturing a pneumatic tire, a strip-shaped strip rubber is spirally wound around a case body having a tread rubber held on a drum by a ribbon winding method to obtain a sidewall-on-tread (SWOT) structure. At that time, it is known that the crimping member is pressed against the strip rubber (see, for example, Patent Documents 1 and 2).

However, in the above-mentioned conventional method, the state in which the strip rubber is attached to the case body tends to be insufficient. Further, there is also a problem that air is easily mixed between the strip rubbers to be wound, that is, so-called air entry is likely to occur.

Japanese Patent Publication No. 2014-512992 Japanese Unexamined Patent Publication No. 2004-338626

INDUSTRIAL APPLICABILITY The present invention is a method of winding strip rubber to form sidewall rubber, but the pressure-bonding state with the case body is good, and subsequent vulcanization molding can be smoothly performed. The first subject is to provide a manufacturing method and an apparatus.
A second object of the present invention is to provide a method and an apparatus for manufacturing a pneumatic tire that can effectively prevent air entry.

The present invention has a crown portion and side portions located on both sides of the crown portion as means for solving the first problem, and a first sidewall is provided on the outer side of the side portion in the tire width direction. A sidewall forming step of forming a second sidewall portion on the outer side of the first sidewall portion in the tire radial direction of the side portion with respect to the case body provided with the portion and the tread rubber on the outer periphery of the crown portion. The step of forming the second sidewall portion includes the first winding step of forming the first winding body by spirally winding the strip rubber around the side portion, and the first winding step. From the second winding step of spirally winding strip rubber around the outer surface of the winding body in the tire width direction to form the second winding body, and from the intermediate portion in the tire radial direction of the second winding body. The first pressing step of moving the stitcher toward one end side in the tire radial direction and pressing the strip rubber of the second winding body against the first winding body by the stitcher, and the second winding body. A second pressing step in which the direction is changed on one end side to move the stitcher toward the other end side in the tire radial direction, and the strip rubber of the second winding body is pressed against the first winding body by the stitcher. And, including, provide a method of manufacturing a pneumatic tire.

According to this, the contact surface between the case main body and the strip rubber wound around the case main body can be appropriately crimped. That is, by pressing the strip rubber from the middle portion of the second winding body toward one end side, the strip rubber can be crimped to the side portion without causing wrinkles or the like on the strip rubber. In addition, by pressing the strip rubber toward the tread rubber side with the direction in which the strip rubber is wound reversed, the strip rubber can be crimped to the tread rubber without causing wrinkles on the strip rubber. can. This makes it possible to smoothly perform the subsequent vulcanization molding.

It is preferable to include a first air bleeding groove forming step of forming an air bleeding groove on the outer surface of the strip rubber wound in the first winding step in the tire width direction .

According to this, even if air tries to remain in the overlapping portion of the strip rubber, it can be smoothly discharged through the air bleeding groove, and the second problem can be solved.

The first air bleeding groove forming step is performed by pressing a jagged roller in which ridges along the axial direction are juxtaposed on the outer peripheral surface in the circumferential direction over the entire circumference at predetermined intervals and rotating the strip rubber. Is preferable.

According to this, it is possible to sequentially form an air bleeding groove in the strip rubber by the ridges formed on the outer peripheral surface of the jagged roller only by pressing the jagged roller against the strip rubber.

The strip rubber is preferably strip-shaped with a substantially triangular cross section.

According to this, even if it is a dent at the boundary portion with the side portion formed by attaching the tread rubber to the case body, the strip rubber can be attached without a gap.

In this case, the steps for forming the first sidewall portion include the first grooving step for forming the first air bleeding groove in the central region having the thickest thickness of the strip rubber and the tire width direction of the strip rubber. The outer surface includes a second grooving step of forming a second air bleeding groove in a lateral region displaced from the air bleeding groove in the central region formed in the first grooving step. Is preferable.

According to this, an air bleeding groove can be formed also in the thinned portion of the strip rubber, and the air bleeding effect can be further enhanced.

When the green tire formed through the sidewall forming step is vulcanized and molded, it is preferable to evacuate the inside of the mold.

According to this, air can be reliably discharged from the air vent groove that is not completely crushed. Therefore, it is possible to reliably prevent air from entering during vulcanization molding.

In the grooving step, it is preferable to use a knurled roll.

According to this, when the strip rubber is wound, air can be discharged in various directions, and it is possible to more effectively prevent air from entering.

The present invention has a crown portion and side portions located on both sides of the crown portion as means for solving the above problems, and a first sidewall portion is provided on the outer side of the side portion in the tire width direction. A drum that rotatably holds the case body provided with tread rubber on the outer periphery of the crown portion, a driving means for driving the drum to rotate around the axis, and the first sidewall portion of the side portions. A supply means for supplying strip-shaped strip rubber to the outside in the tire radial direction, a moving means for moving the supply means relative to the drum in the axial direction of the drum, and a strip wound around the case body. A crimping member that presses the outer surface of the rubber in the tire width direction, a grooving member that presses a jagged roller against the outer surface of the strip rubber pressed by the crimping member to form an air bleeding groove, and the strip rubber inside the tire width direction. The tire is provided with a stitcher to be pressed against the tire, the driving means, the feeding means, the moving means, the crimping member, the grooving member, and the control means for driving and controlling the stitcher. The strip rubber is supplied to the drum by the supply means while the supply means is moved by the moving means, and the strip rubber is spirally wound around the side portion while being pressed by the crimping member. In the first winding step of forming the first winding body provided with the air bleeding groove by the grooving member, the drum is rotated by the driving means, and the supply means is moved by the moving means. The strip rubber is supplied to the drum by the supply means, and the strip rubber is spirally wound around the outer surface of the first winding body in the tire width direction while being pressed by the crimping member, and is wound by the grooving member. The stitcher is moved from the middle portion of the second winding body in the tire radial direction to the one end side in the tire radial direction in the second winding step of forming the second winding body provided with the air bleeding groove. The first pressing step of pressing the strip rubber of the second winding body against the first winding body by the stitcher, and the other end in the tire radial direction by changing the direction on the one end side of the second winding body. Provided is a pneumatic tire manufacturing apparatus for moving the stitcher toward the side and performing a second pressing step of pressing the strip rubber of the second winding body against the first winding body by the stitcher. ..

According to the present invention, since the pressing of the strip rubber is started from the middle portion of the second winding body, it is possible to press the strip rubber at both ends without causing wrinkles or the like. As a result, the strip rubber can be securely crimped to the case body and the subsequent vulcanization molding can be smoothly performed.

It is a meridian partial sectional view of the green tire which concerns on this embodiment. It is a meridian half cross section of the pneumatic tire obtained by vulcanizing and molding the green tire of FIG. 1. It is a schematic explanatory drawing of the manufacturing apparatus used in the sidewall forming process which concerns on this embodiment. It is a front view of the grooved roller used in FIG. It is a partial perspective view of the strip rubber in which the air bleeding groove is formed by the grooved roller shown in FIG. It is sectional drawing which shows the winding state of the strip rubber by the manufacturing apparatus of FIG. It is a meridian partial sectional view of the tire case which concerns on this embodiment. FIG. 7 is a partial cross-sectional view of the meridian showing a state in which the first sidewall portion is formed. FIG. 8 is a partial cross-sectional view of the meridian showing a state in which the first winding body is formed. FIG. 9 is a partial cross-sectional view of the meridian showing a state in which the second winding body is formed. FIG. 3 is a partial cross-sectional view taken along the meridian showing a state in which the green tire of FIG. 10 is pressed by a stitcher.

Hereinafter, embodiments according to the present invention will be described with reference to the accompanying drawings. It should be noted that the following description is merely an example and is not intended to limit the present invention, its application, or its use. In addition, the drawings are schematic, and the ratio of each dimension is different from the actual one.

FIG. 1 shows a partial cross-sectional view of the meridian of the green tire 1 formed by the pneumatic tire manufacturing apparatus (not shown) according to the present embodiment. Further, FIG. 2 shows a meridian semi-cross-sectional view of the product tire 2 obtained by vulcanizing and molding the green tire 1.

The green tire 1 has a sidewall 4 integrated with a side portion 13 of a tire case 3.

The tire case 3 includes a case body 5 and a tread ring 6.

The case body 5 includes a bead core 7, a bead filler 8, a carcass ply 9, an inner liner 10, and a rim strip rubber 11. The case body 5 has a cylindrical shape as a whole, and includes a crown portion 12 constituting an outer peripheral portion and side portions 13 on both side surfaces thereof.

The bead core 7 is formed by bundling a plurality of wires into an annular shape, and is arranged with a space between the left and right sides (in FIG. 1, only one bead core 7 is shown). The bead filler 8 is connected to the bead core 7 and serves to increase the rigidity of this portion. The carcass ply 9 is toroid-like and is composed of at least one ply whose carcass cord is covered with rubber. Both sides of the carcass ply 9 are wound around the bead core 7 and the bead filler 8. However, the winding height of the carcass ply 9 is not limited to that shown in the figure. The inner liner 10 is arranged inside the carcass ply 9. The rim strip rubber 11 is arranged outside the bead core 7 and the bead filler 8. A tread ring 6 is integrated with the crown portion 12.

The tread ring 6 includes a belt 14 and a belt reinforcing layer 15 from the inner peripheral side, and a tread rubber 16 is arranged on the outer peripheral portion. The tread ring 6 is integrated with the outer peripheral surface of the crown portion 12 of the case body 5.

The sidewall 4 includes a first sidewall portion 17 and a second sidewall portion 18. The first sidewall portion 17 is formed by the first sidewall forming device 19 shown in FIG. The second sidewall portion 18 is not shown in detail, but is formed by the second sidewall forming device 20 (see FIG. 7).

The first sidewall forming device 19 includes a first drum 21, a rubber supply unit 22, a crimping member 23, a first grooving member 24, a second grooving member 25, and the like.

The first drum 21 is formed in a cylindrical shape centered on the axis O. The outer peripheral surface of the first drum 21 is composed of a metal segment, a bladder, or the like that can be expanded or contracted in the radial direction. Further, the first drum 21 is rotated in the counterclockwise direction in FIG. 3 with the axis O as the center by a driving means such as a motor (not shown).

The rubber supply unit 22 is for supplying the strip-shaped strip rubber 26, and includes a die 29 having a base 28 at the tip end portion of the extruder 27. The rubber supply unit 22 separates the base 28 from the outer peripheral surface of the first drum 21 in the radial direction of the first drum 21 by a driving means (moving means) such as a motor (not shown), and the axial direction of the first drum 21. (The first drum 21 may be moved in the axial direction thereof, but it is sufficient that the first drum 21 and the rubber supply unit 22 can be relatively moved). The base 28 is formed with an opening for extruding the strip rubber 26. The cross-sectional shape of the opening is a flat shape in which the width dimension in the height direction orthogonal to this direction gradually decreases from the central portion toward both ends. As a result, the strip rubber 26 extruded from the base 28 is flat as a whole, but strictly speaking, it is formed in a triangular cross-sectional shape in which the central portion is the thickest and gradually becomes thinner toward both sides. Specifically, the width is 15 to 35 mm, and the maximum thickness at the center is 1.0 to 3.0 mm. Preferably, the width is 20 to 25 mm and the maximum thickness at the center is 2.0 to 3.0 mm.

The crimping member 23 is formed by rotatably attaching a cylindrical crimping roller 32 to the tip of a piston 31 that can be moved forward and backward by a cylinder 30 with a rotation shaft 32a as a center. The crimping roller 32 is arranged so that the axial direction of the rotating shaft 32a is parallel to the axial direction of the first drum 21. By driving the cylinder 30 and advancing the piston 31, the strip rubber 26 supplied from the rubber supply unit 22 can be pressed and attached to the outer surface of the tire case 3 on the outer peripheral surface of the crimping roller 32. ing.

The first grooving member 24 has a first jagged roller 35 rotatably attached to the tip of a first piston 34 that can be moved forward and backward by the first cylinder 33. As shown in FIG. 3, the first jagged roller 35 is composed of a pair arranged at the tip of the first piston 34 with a slight gap in the axial direction with the rotation shaft 35a as the center. On the outer peripheral surface of the first jagged roller 35, ridges 35b along the axial center direction are juxtaposed over the entire circumference at predetermined intervals in the circumferential direction. Each ridge 35b has a substantially triangular cross section. The most protruding portion on the outer diameter side is not an acute angle but is composed of a flat surface or a curved surface. Similar to the crimping member 23, the first jagged roller 35 is arranged so that the axial direction of the rotating shaft 35a is parallel to the axial direction of the first drum 21. Then, the first cylinder 33 is driven to advance the first piston 34, and the strip rubber 26 attached to the outer surface of the tire case 3 is pressed on the outer peripheral surface of the first jagged roller 35 to press the air bleeding groove 36 (FIG. 5). Then, the reference numeral 36a is formed as the first air bleeding groove). The pressing position of the strip rubber 26 by the first jagged roller 35 is a thick portion in the center, as will be described later. The first Giza Roller 35 may be composed of one integral piece. Further, the shape of the outer peripheral surface of the first jagged roller 35 may be formed by knurling or grooving.

The second grooving member 25 has the same configuration as the first grooving member 24. That is, a cylindrical second jagged roller 39 is rotatably attached to the tip of the second piston 38 that can be moved forward and backward by the second cylinder 37 with the rotation shaft 39a as the center. However, the pressing position of the strip rubber 26 by the second jagged roller 39 is a thin-walled portion shifted laterally from the central portion. As a result, the air bleeding groove 36 (indicated by reference numeral 36b as the second air bleeding groove in FIG. 5) can be formed in the portion that cannot be formed by the first jagged roller 35.

The second sidewall forming device 20 includes a second drum 40 (shaping drum), a rubber supply unit 22, a crimping member 23, a first jagged roller 35, a second jagged roller 39, a stitcher 41 (see FIG. 11), and the like. These components have the same configuration as the components of the first sidewall forming device 19.

(Method of forming green tire 1)
Next, a method of forming the green tire 1 will be described. The formation of the green tire 1 is a first step of forming the tire case 3, a second step of forming the first case to be the first sidewall portion 17, and a third step of forming the second case to be the tread ring 6. This is performed by a fourth step of combining the first case and the second case in the tire case 3, and a fifth step of forming the second sidewall portion 18 in the tire case 3. Hereinafter, each of these steps will be described.

(First step)
First, the inner liner 10 and then the carcass ply 9 are wound around the outer peripheral surface of the band drum (not shown) to form a cylindrical shape. The bead core 7 and the bead filler 8 are arranged on both sides of the carcass ply 9 in the width direction. Both ends of the carcass ply 9 are folded back (turned up) to cover the outer surfaces of the bead core 7 and the bead filler 8. The tire case 3 is obtained by attaching the rim strip rubber 11 to the region including the folded portion.

(Second step)
Subsequently, as shown in FIG. 3, the strip rubber 26 is supplied from the rubber supply portion 22 to the first drum 21 to form a first case to be the first sidewall portion 17.

The strip rubber 26 to be supplied is spirally wound around the first drum 21. At this time, the strip rubber 26 is pressed against the outer surface of the tire case 3 by the crimping member 23. In the winding of the strip rubber 26 on the first round, the first drum 21 is not moved in the axial direction but is parallel to the rotation direction. In the winding of the strip rubber 26 from the second lap onward, the rubber supply unit 22 is moved at a predetermined feed rate toward one of the axial directions of the first drum 21. Here, as shown in FIG. 6, the feed amount of the rubber supply unit 22 is halved (for example, 5.0 mm to 15.0 mm) of the width dimension of the air trip rubber 26. Determine the amount. That is, the strip rubber 26a wound first is spirally wound in a state where the center position C and the one side edge position E of the strip rubber 26b to be wound next are aligned with each other.

While the strip rubber 26 is wound, pressing is performed by the first jagged roller 35 and the second jagged roller 39.

The pressing of the strip rubber 26 by the first jagged roller 35 is performed immediately after the strip rubber 26 is pressed against the outer surface of the tire case 3 by the crimping member 23. As a result, a plurality of air bleeding grooves 36 are formed on the outer surface of the strip rubber 26. Here, the pressing of the first jagged roller 35 against the strip rubber 26 is the central thickest portion. As a result, a plurality of air bleeding grooves 36 extending in the width direction of the strip rubber 26 are formed at regular intervals in the winding direction.

The strip rubber 26 is pressed by the second jagged roller 39 on the opposite side of the pressing position by the first jagged roller 35 about the center of rotation of the first drum 21. Further, the pressing to the strip rubber 26 is performed by shifting the position from the pressing position of the first jagged roller 35. Grooving by the second jagged roller 39 is performed by shifting the position of the strip rubber 26 of the first roll to the portion to which the second roll is wound on one side, not to the central portion having the largest thickness. Further, the grooving by the second jagged roller 39 is similarly performed by shifting the position to the portion where the strip rubber 26 is wound next in the same manner for the second and subsequent windings. As a result, the air bleeding groove 36 can be formed even in a thin portion that is difficult to form by the first jagged roller 35.

The strip rubber 26, which is wound around the first drum 21 and pressed by the crimping member 23, and the air bleeding groove 36 is formed by the first jagged roller 35 and the second jagged roller 39, is sequentially wound so as to partially overlap. When the crimping member 23 is pressed against the strip rubber 26 of the second roll to be wound, the crimping member 23 is crimped to the strip rubber 26 of the first roll. Since the air bleeding groove 36 is formed in the overlapping portion with the second winding in the first winding, the air in the overlapping portion is discharged to the outside through the air bleeding groove 36, and loses its place to generate an air pool. I won't let you. Further, even if air remains in the air bleeding groove 36, since the inside of the mold is evacuated at the time of vulcanization molding described later, the air does not remain and can be reliably discharged. When the strip rubber 26 is wound to a predetermined position in this way, the tread rubber 16 is wound once on the same circumference in the tire radial direction. This gives the first case.

When the first case is obtained, the jagged roller is separated from the strip rubber 26, and the formation of the air bleeding groove 36 on the outer surface of the strip rubber 26 is stopped.

(Third step)
The belt 14 and the belt reinforcing layer 15 are wound around the outer peripheral surface of the belt drum (not shown). Then, by forming the tread rubber 16 on the outer peripheral surface of the belt reinforcing layer 15, a second case which becomes a cylindrical tread ring 6 is obtained. The tread rubber 16 can be formed, for example, by a ribbon winding method in which a strip rubber 26 is spirally wound a plurality of times along the tire circumferential direction.

(4th step)
The tire case 3, the first case and the second case are arranged on the outer peripheral side of the second drum 40. In this state, the tire case 3 is expanded to the outer diameter side by the second drum 40, and the outer peripheral surface thereof is brought into close contact with the inner peripheral surfaces of the first case and the second case to be deformed. As a result, as shown in FIG. 7, the tread ring 6 and the first sidewall portion 17 are formed with respect to the tire case 3, and the main portion of the green tire 1 excluding the second sidewall portion 18 is obtained.

(Fifth step)
While rotating the second drum 40, the strip rubber 26 is supplied from the rubber supply unit 22 (not shown). The first roll of the supplied strip rubber 26 is wound on the same circumference on both ends of the tread rubber 16. Specifically, as shown in FIG. 8, the strip rubber 26 is wound so that the center position C and the boundary position B between the tread rubber 16 and the case body 5 match. From the second winding, the strip rubber 26 is spirally wound toward the upper end side (first direction FD) of the first sidewall portion 17 by moving the rubber supply portion 22 (the feed amount is, for example, the strip). The feed rate can be determined so as to be a value of 1/2 of the width dimension of the rubber 26). At this time, the strip rubber 26 is pressed against the tire case 3 by the crimping member 23. Further, the jagged roller is pressed against the outer surface of the wound strip rubber 26 to form the air bleeding groove 36. Then, as shown in FIG. 9, the strip rubber 26 reaches the upper end portion of the first sidewall portion 17 , whereby the first winding body 18a is obtained (first winding step).

When the strip rubber 26 reaches the upper end portion of the first sidewall portion 17 , the feed direction of the rubber supply portion 22 is set to the opposite direction (second direction SD), and the strip rubber 26 is spirally wound by moving at a predetermined feed rate. (The feed rate at this time can also be determined so that the feed rate is halved of the width dimension of the strip rubber 26, as described above.) The strip rubber 26 is wound to a position that covers at least the first winding body 18a beyond the boundary position B between the tread rubber 16 and the case body 5. Here, the strip rubber 26 is wound up to the side edge 16a of the outer surface where the thickness on both sides of the tread rubber 16 begins to decrease. Here, as in the first winding step, the jagged roller 39 of the second grooving member 25 is pressed against at least the portion of the previously wound strip rubber 26 covered by the strip rubber 26 to be wound. Here, the air bleeding groove 36 is formed in the half of the strip rubber 26 on the winding direction side, but it may be formed as a whole. As a result, as shown in FIG. 10, the second winding body 18b covering the first winding body 18a is formed, and the second sidewall portion 18 is obtained (second winding step). The stitcher 41 is further pressed against the second sidewall portion 18 thus obtained.

In the intermediate portion where the strip rubbers overlap each other, the strip rubbers 26 are in a crimped state and do not shift in position. However, the upper and lower end portions have contact portions with the tread rubber 16 and the first sidewall portion 17 , and the crimping state tends to be insufficient. Further, a thin portion of the strip rubber 26 is located at the upper and lower ends. Therefore, when the stitcher 41 is pressed from the upper end or the lower end of the second sidewall portion 18, the strip rubber 26 is deformed and wrinkled at the contact portion with the tread rubber 16 or the first sidewall portion 17 . May occur. Therefore, as shown in FIG. 11, the pressing of the stitcher 41 is performed at the intermediate portion (neither the upper end portion nor the lower end portion) of the outer surface of the second sidewall portion 18, where the strip rubber 26 is first wound. Start from the part corresponding to. Then, the stitcher 41 is moved to the first sidewall portion 17 side. (First pressing process). As a result, the crimping state between the strip rubbers 26 becomes stronger, and the stitcher 41 reaches the end of the first sidewall portion 17 , so that the strip rubber 26 with respect to the first sidewall portion 17 It is properly crimped without misalignment. When the stitcher 41 reaches the end of the first sidewall portion 17 , the direction is changed so that the stitcher 41 faces the tread rubber 16 side (second pressing step). As a result, the crimping state between the strip rubbers 26 becomes stronger. Further, when the stitcher 41 reaches the end portion of the tread rubber 16, the strip rubber 26 is appropriately crimped to the tread rubber 16 without being displaced, and the green tire 1 is completed.

As described above, in the pressing step, the crimping method by the stitcher 41 is devised, starting from the intermediate portion of the outer surface of the second sidewall portion 18, moving to the first sidewall portion 17 side, and then changing the direction. Then, it is directed to the tread rubber 16 side. Therefore, it is possible to improve the crimping state at the contact portion with the tread rubber 16 and the first sidewall portion 17 , which tend to be insufficient.

The stitcher 41 may be moved beyond the side edge of the strip rubber 26 toward the first direction FD in the first pressing process, or may be moved toward the second direction SD in the second pressing process. May be moved beyond the side edges of.

The green tire 1 formed by the above step has the following characteristics.

When forming the sidewall 4, an air bleeding groove 36 extending in the tire circumferential direction was formed on the outer surface of the strip rubber 26 and pressed by the stitcher 41, so that the first winding body 18a and the second winding body 18b were formed. Regardless of which of the above is formed, air entry between the strip rubbers 26 can be suppressed.

Since the stitcher 41 is pressed against the middle portion of the outer surface of the strip rubber 26 and then moved to the rim strip rubber 11 side, the strip rubber 26 and the rim strip rubber 11 can be in a good crimping state. can. Further, since the strip rubber 26 is folded back from the end of the rim strip rubber 11 and moved and pressed against the end of the tread rubber 16, a good crimping state is obtained between the strip rubber 26 and the tread rubber 16. be able to.

By setting the completed green tire 1 in the mold of the vulcanization die and performing vulcanization molding, the pneumatic tire shown in FIG. 2 can be obtained. At this time, the inside of the mold of the vulcanization die is evacuated and the residual air in the air vent groove 36 is discharged. The air bleeding groove 36 is formed so as to communicate with the outside from the overlapping portion of the strip rubber 26. Therefore, vulcanization molding does not generate air pools.

The present invention is not limited to the configuration described in the above embodiment, and various modifications can be made.

In the above embodiment, the jagged rollers 35 and 39 form the air bleeding groove 36 extending in the tire width direction, but by forming the ridges 35b in a grid pattern or the like, not only the tire width direction but also the tire circumferential direction is formed. The air bleeding groove 36 may be formed. The air bleeding grooves 36 do not have to be orthogonal to each other and may intersect diagonally.

In the above embodiment, the feed rate of the strip rubber 26 is determined so that a constant feed amount can be obtained. However, for each rotation of the drum 21, one pitch (for example, the width dimension of the strip rubber 26) is determined. (Value of 1/2) may be shifted.

In the above embodiment, the strip rubber 26 is wound with the same feed amount, but it may be appropriately changed depending on the difference in the thickness of the sidewall 4 and the like. For example, if the tire outer diameter side is closer to the boundary position B between the tread rubber 16 and the case body 5, the feed amount of the strip rubber 26 to be wound around the first winding body 18a is set to be larger, and if it is the tire inner diameter side, the opposite is true. It should be set small to.

In the above embodiment, the first winding body 18a and the second winding body 18b are formed by one strip rubber 26 connected to each other, but each may be formed by a separate strip rubber 26. .. In this case, each strip rubber 26 may be made of the same kind of material or may be made of different materials. Further, the first winding body 18a may be formed and then the second winding body 18b may be formed. However, in order to shorten the process time, the second winding body 18a is formed while the first winding body 18a is formed. Body 18b may be formed. That is, if the second winding body 18b is formed on the outer surface side of the first winding body 18a, for example, the winding of the second winding body 18b is started before the winding of the first winding body 18a is completed. Alternatively, the winding of the first winding body 18a and the winding of the second winding body 18b may be started at the same time.

In the above embodiment, the first winding body 18a and the second winding body 18b are formed by folding back the winding of the strip rubber 26 only once, but by folding back two or more times, the second winding body is formed. A winding body may be further formed on the outside of the attachment body 18b.

In the above embodiment, when the sidewall 4 is formed, the strip rubber 26 is wound from the case body 5 side to the tread rubber 16 side, and then wound from the tread rubber 16 side to the case body 5 side. You may try to do it. That is, the air trip rubber 26, which has the same starting point at the boundary position B between the tread rubber 16 and the case body 5, is wound from the tread rubber 16 side to the case body 5 side, and then the tread rubber 16 is wound from the case body 5 side. You may wrap it around the side.

1 ... Green tire 2 ... Product tire 3 ... Tire case 4 ... Sidewall 5 ... Case body 6 ... Tread ring 7 ... Bead core 8 ... Bead filler 9 ... Carcass ply 10 ... Inner liner 11 ... Rim strip rubber 12 ... Crown part 13 ... Side part 14 ... Belt 15 ... Belt reinforcement layer 16 ... Tread rubber 16a ... Side edge 17 ... 1st sidewall part 18 ... 2nd sidewall part 18a ... 1st winding body 18b ... 2nd winding body 19 ... 1st Sidewall forming device 20 ... Second sidewall forming device 21 ... First drum 22 ... Rubber supply part 23 ... Crimping member 24 ... First grooving member 25 ... Second grooving member 26 ... Strip rubber 27 ... Extruder 28 ... Base 29 ... Die 30 ... Cylinder 31 ... Piston 32 ... Crimping roller 33 ... 1st cylinder 34 ... 1st piston 35 ... 1st rubber roller 36 ... Air bleeding groove 37 ... 2nd cylinder 38 ... 2nd piston 39 ... 2nd rubber roller 40 ... 2nd drum 41 ... Stitcher

Claims (7)

A case body having a crown portion and side portions located on both sides of the crown portion, having a first sidewall portion on the outer side in the tire width direction of the side portion, and having a tread rubber on the outer periphery of the crown portion. On the other hand, the side wall forming step of forming the second sidewall portion on the tire radial outer side of the first sidewall portion among the side portions is included.
The step of forming the second sidewall portion is
The first winding step of forming the first winding body by spirally winding the strip rubber around the side portion,
The second winding step of spirally winding the strip rubber around the outer surface of the first winding body in the tire width direction to form the second winding body.
The stitcher is moved from the middle portion in the tire radial direction of the second winding body toward one end side in the tire radial direction, and the strip rubber of the second winding body is pressed against the first winding body by the stitcher. The first pressing process and
The direction is changed on the one end side of the second winding body to move the stitcher toward the other end side in the tire radial direction, and the strip rubber of the second winding body is attached to the first winding body by the stitcher. A method for manufacturing a pneumatic tire, which comprises a second pressing step of pressing against the body . The method for manufacturing a pneumatic tire according to claim 1, further comprising a first air bleeding groove forming step of forming an air bleeding groove on the outer surface of the strip rubber wound in the first winding step in the tire width direction . The first air bleeding groove forming step is performed by pressing a jagged roller in which ridges along the axial direction are juxtaposed on the outer peripheral surface in the circumferential direction over the entire circumference at predetermined intervals and rotating the strip rubber. The method for manufacturing a pneumatic tire according to claim 2. The method for manufacturing a pneumatic tire according to any one of claims 1 to 3, wherein the strip rubber has a strip shape having a substantially triangular cross section. The step of forming the first sidewall portion is
A first grooving step of forming a first air bleeding groove in the thickest central region of the strip rubber,
A second groove is formed on the outer surface of the strip rubber in the tire width direction in a lateral region displaced from the air bleeding groove in the central region formed in the first grooving step. The attachment process and
4. The method for manufacturing a pneumatic tire according to claim 4. The method for manufacturing a pneumatic tire according to any one of claims 1 to 5, wherein the inside of the mold is evacuated when the green tire formed through the sidewall forming step is vulcanized and molded. A case body having a crown portion and side portions located on both sides of the crown portion, having a first sidewall portion on the outer side in the tire width direction of the side portion, and having a tread rubber on the outer periphery of the crown portion. , A drum that rotatably holds around the axis, and
A driving means for rotationally driving the drum and
A supply means for supplying strip-shaped strip rubber to the outer side of the side portion in the tire radial direction of the first sidewall portion ,
A moving means for moving the supply means relative to the drum in the axial direction of the drum, and a moving means.
A crimping member that presses the outer surface of the strip rubber wrapped around the case body in the tire width direction , and
A grooving member that presses a jagged roller against the outer surface of the strip rubber pressed by the crimping member to form an air bleeding groove, and a grooving member.
A stitcher that presses the strip rubber inward in the tire width direction ,
With the driving means, the supplying means , the moving means , the crimping member, the grooving member, and the control means for driving and controlling the stitcher.
Equipped with
The control means is
The strip rubber is supplied to the drum by the supply means while the drum is rotated by the drive means and the supply means is moved by the movement means, and the strip rubber is spirally crimped to the side portion. The first winding step of forming the first winding body provided with the air bleeding groove by winding while pressing by the member, and the grooving member.
The strip rubber is supplied to the drum by the supply means while the drum is rotated by the drive means and the supply means is moved by the moving means, and the outer surface of the first winding body in the tire width direction is provided. In the second winding step , the strip rubber is spirally wound while being pressed by the crimping member to form a second winding body provided with the air bleeding groove by the grooving member .
The stitcher is moved from the middle portion in the tire radial direction of the second winding body toward one end side in the tire radial direction, and the strip rubber of the second winding body is transferred by the stitcher to the first winding body. The first pressing process to press against
The direction is changed on the one end side of the second winding body to move the stitcher toward the other end side in the tire radial direction, and the strip rubber of the second winding body is transferred by the stitcher to the first winding body . With the second pressing process to press against the attachment
Pneumatic tire manufacturing equipment to perform.

Images