JP2019038204A - Method and apparatus for manufacturing pneumatic tire - Google Patents

Abstract

To reliably prevent an occurrence of air inclusion even in a method of forming a sidewall rubber by winding a strip rubber.SOLUTION: In a side wall forming step, at a case body 7 having a tread rubber 8 on an outer periphery of a crown portion 13 forming an outer peripheral portion, at least a part of a sidewall rubber 26 is formed by winding a strip-like strip rubber 17 on part of a side portion 14 forming both side surfaces and the tread rubber 8. The sidewall forming step includes a first winding step of forming a first wound body 28 by winding the strip rubber 17 from the tread rubber 8 or the case body 7 toward the remaining one, a second winding step of forming a second wound body 29 by winding the strip rubber 17 around the first wound body, and a grooving step for forming an air vent groove 27 on an outer surface of the strip rubber 17.SELECTED DRAWING: Figure 1

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 ribbon-shaped method is used to spirally wrap a strip-shaped strip rubber around a case body having a tread rubber held on a drum to obtain a sidewall on tread (SWOT) structure. At this time, one in which the strip rubber is cooled by blowing air is known (for example, see Patent Document 1).

  However, in the conventional method, there is a problem that air is easily mixed between the strip rubbers to be wound, that is, so-called air is easily generated.

JP 2015-100953

  It is an object of the present invention to provide a method and an apparatus for manufacturing a pneumatic tire that can effectively prevent air entry even if the method is a method of forming a sidewall rubber by winding a strip rubber.

As a means for solving the above problems, the present invention provides:
A case body having a crown portion constituting an outer peripheral portion and side portions constituting both side surface portions and provided with a tread rubber on an outer periphery of the crown portion, a band-like shape on the side portion and a part of the tread rubber. A side wall forming step of forming at least a part of the side wall rubber by winding the strip rubber of
The sidewall forming step includes
A first winding step of forming a first wound body by winding the strip rubber toward the other remaining from either the tread rubber or the case body;
A second winding step of winding the strip rubber around the outer surface of the first winding body to form a second winding body;
A grooving step of forming an air vent groove on the outer surface of the strip;
A method for manufacturing a pneumatic tire is provided.

  According to this, since the air bleeding groove can be formed in the previously wound strip rubber, air can be discharged through the air bleeding groove when the strip rubber is wound next time. Accordingly, it is possible to prevent air from entering between the strip rubber wound first and the strip rubber wound later.

  In the second winding step, the second winding body is formed by folding the strip rubber forming the first winding body in the opposite direction and winding it around the outer surface of the first winding body. Is preferred.

  According to this, both a 1st winding body and a 2nd winding body can be performed at once by a series of winding operation | work of a strip rubber, and work efficiency is good.

In the first winding step, the first wound body is formed so as to cover an end portion of the tread rubber by winding the strip rubber a plurality of times.
In the second winding step, the strip rubber can be folded back and wound a plurality of times until at least the side edge position of the tread rubber is exceeded to form the second winding body.

  In the grooving step, it is preferable that the outer surface of the strip rubber is knurled by the stitcher.

  According to this, when winding the strip rubber, air can be discharged in various directions, and air entry can be further effectively prevented.

The strip rubber has a cross-sectional shape whose thickness decreases toward both ends in the width direction,
In the first winding step, it is preferable that the center position in the width direction of the strip rubber coincides with the boundary position between the tread rubber and the case body, and the first turn is wound in parallel with the boundary position.

  According to this, it is possible to effectively prevent air from remaining by positioning the central position in the width direction of the strip rubber having a large thickness at the boundary position between the tread rubber and the case main body having a large step.

As a means for solving the above problems, the present invention provides:
A drum having a crown portion constituting an outer peripheral portion and side portions constituting both side surface portions, and holding a case main body provided with a tread rubber on an outer periphery of the crown portion;
Drive means for rotationally driving the drum;
Supply means for supplying strip-shaped strip rubber;
A stitcher that forms an air vent groove on the outer surface of the strip rubber wound around the case body;
Moving means for moving the supply means relative to the drum in the axial direction of the drum;
Control means for forming an air bleeding groove on the outer surface of the strip rubber by wrapping a strip rubber around the outer surface of the case body by driving and controlling the driving means and the moving means, and driving the stitcher.
An apparatus for manufacturing a pneumatic tire is provided.

  According to the present invention, since the air vent groove is formed in the previously wound strip rubber, it is possible to prevent air from entering the next strip rubber.

It is a schematic explanatory drawing of the manufacturing apparatus used for the side wall formation process which concerns on this embodiment. It is a front view of the giza roll used for FIG. It is a meridian half section view of a green tire concerning this embodiment. It is a meridian half section view of a tire case concerning this embodiment. FIG. 5 is a meridian partial cross-sectional view showing a state in which the first wound body is formed in FIG. 4. It is an expanded sectional view of the 1st volume body part of FIG. FIG. 6 is a meridian partial cross-sectional view showing a state where the second wound body is formed in FIG. 5. It is a meridian partial sectional view of a tire case according to another embodiment. It is a meridian partial sectional view showing a state in which the first attached body is formed in FIG. FIG. 10 is a meridian partial cross-sectional view showing a state in which the second wound body is formed in FIG. 9.

  Embodiments according to the present invention will be described below with reference to the accompanying drawings. In addition, the following description is only illustrations essentially and does not intend restrict | limiting this invention, its application thing, or its use. Further, the drawings are schematic, and the ratio of each dimension is different from the actual one.

  FIG. 1 shows a sidewall forming apparatus 1 constituting a part of a pneumatic tire manufacturing apparatus according to this embodiment. The sidewall forming apparatus 1 includes a drum 2, a rubber supply unit 3, a pressure roller 4, a stitcher 5, and the like.

  The drum 2 is formed in a cylindrical shape centered on the axis. The outer peripheral surface of the drum 2 is composed of a metal segment or a bladder that can be expanded and contracted in the radial direction. The drum 2 is configured to be able to hold a tire case 6 (see FIG. 4) formed in a separate process by its outer peripheral surface in a state of being expanded to the outer diameter side. The drum 2 is rotated about the axis by a driving means such as a motor (not shown).

  As shown in FIG. 4, the tire case 6 is obtained by integrating a tread rubber 8 with a case body 7.

  The case body 7 includes a bead core 9, a carcass ply 10, an inner liner 11, and a rim strip rubber 12. The case main body 7 has a cylindrical shape as a whole, and includes a crown portion 13 constituting an outer peripheral portion and side portions 14 on both side surfaces thereof.

  The bead core 9 is formed by bundling a plurality of wires in an annular shape and is arranged with a space left and right (in FIG. 4, only one bead core 9 is shown). The carcass ply 10 has a toroidal shape and is composed of at least one ply in which a carcass cord is covered with rubber. Both sides of the carcass ply 10 are wound around the bead core 9. The inner liner 11 is disposed inside the carcass ply 10. The rim strip rubber 12 is disposed outside the bead core 9.

  The tread rubber 8 is disposed on the crown portion 13 of the case body 7 via a belt 15 and a belt reinforcing layer 16.

  Returning to FIG. 1, the rubber supply unit 3 is for supplying a strip-shaped strip rubber 17 and includes a die 19 having a base 18 at a tip portion of the extruder. The rubber supply unit 3 reciprocates along the axial direction of the drum 2 by bringing the base 18 into and out of contact with the outer peripheral surface of the drum 2 by driving means (moving means) such as a motor (not shown). (The drum 2 may be moved in the axial direction as long as the drum 2 and the rubber supply unit 3 can move relative to each other). An opening for extruding the strip rubber 17 is formed in the base 18. The cross-sectional shape of the opening is a flat shape whose width gradually narrows from the center toward both ends. As a result, the strip rubber 17 pushed out from the base 18 is generally flat, but strictly speaking, the strip rubber 17 is formed in a triangular cross section that is thickest at the center 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 central maximum thickness is 2.0 to 3.0 mm.

  The pressure roller 4 has a cylindrical shape, and is attached to the tip of a piston 21 that can be advanced and retracted by the cylinder 20 so as to be rotatable about a rotation shaft 4a. The pressure roller 4 is arranged so that the axial center direction of the rotation shaft 4 a is parallel to the axial center direction of the drum 2. By driving the cylinder 20 and advancing the piston 21, the strip rubber 17 supplied from the rubber supply unit 3 can be pressed against the outer surface of the tire case 6 on the outer peripheral surface of the pressure roller 4. ing.

  The stitcher 5 has a cylindrical roller rotatably attached to the tip of a piston 23 that can be advanced and retracted by a cylinder 22. The rollers are in the form of gears (hereinafter referred to as serrated rollers 24), and as shown in FIG. 2, a pair of rollers are arranged with a slight gap in the axial direction around the rotation shaft 24a at the tip of the piston 23. It consists of However, the knurled roller 24 may be configured as one piece. Further, on the outer peripheral surface of the serrated roller 24, protrusions 24b along the axial direction are arranged in parallel along the circumferential direction at predetermined intervals over the entire circumference. The cross section of each protrusion 24b has a triangular shape. However, the most protruding portion is not an acute angle, but is constituted by a flat surface or a curved surface. The shape of the outer peripheral surface of the serrated roller 24 may be formed by knurling or grooving.

  Next, a method for forming a green tire using the green tire forming apparatus having the above-described configuration will be described.

  In a separate process, the tire case 6 is formed by the following known method (tire case forming process).

  First, the inner liner 11 and the carcass ply 10 are formed in a cylindrical shape on the outer peripheral surface of the drum 2. Then, the bead cores 9 are arranged on both sides in the width direction of the carcass ply 10. Subsequently, the end portion of the carcass ply 10 is folded to wrap the bead core 9 to obtain the cylindrical case body 7.

  Further, the belt 15 and the belt reinforcing layer 16 are wound around the outer peripheral surface of another drum (not shown). Then, the tread ring 25 is formed by forming the tread rubber 8 on the outer peripheral surface of the belt reinforcing layer 16. The tread rubber 8 can be formed by, for example, a ribbon winding method in which a strip-shaped strip rubber 17 is spirally wound a plurality of times along the tire circumferential direction.

  Next, the tread ring 25 is disposed on the outer peripheral side of the case body 7. In this state, by expanding the drum 2 to the outer diameter side, the case body 7 is expanded and deformed in the tire radial direction, and the outer peripheral surface thereof is brought into close contact with the inner peripheral surface of the tread ring 25. Thereby, the tire case 6 provided with the crown part 13 and the side parts 14 on both sides shown in FIG. 4 is obtained.

  Side wall rubber 26 is formed on the hollow cylindrical tire case 6 thus obtained as follows (side wall forming step).

  A strip rubber 17 is supplied from the rubber supply unit 3 to the drum 2. The supplied strip rubber 17 is pressed against the outer surface of the tire case 6 by the pressure roller 4. At this time, as shown in FIG. 4, the thickest central portion C of the strip rubber 17 is opposed to the boundary position B between the tread rubber 8 of the tire case 6 and the case body 7. The first round of the strip rubber 17 is wound parallel to the direction in which the boundary position extends. At this time, the adhesive roller 24 of the stitcher 5 is pressed against the strip rubber 17 while the strip rubber 17 is adhered to the tire case 6. Thereby, a plurality of air bleeding grooves 27 extending in the winding direction, that is, the tire circumferential direction are formed on the outer surface of the strip rubber 17 to be attached.

  Subsequently, the rubber supply unit 3 is moved at a predetermined feed speed toward one side in the axial direction of the drum 2 (upward in FIG. 4). Here, as shown in FIG. 5, the feed rate is determined so that the feed amount of the rubber supply unit 3 becomes a value of ½ of the width dimension of the strip rubber 17. In other words, the strip rubber 17a is wound spirally in a state where the center position C of the strip rubber 17a wound earlier and the one side edge position E of the strip rubber 17b wound next are matched. And the 1st winding body 28 is obtained when the other side edge of the strip rubber | gum 17 reaches the side edge of the surface side of the tread rubber 8 (1st winding process).

  As shown in FIG. 6, while the strip rubber 17 is wound spirally, the stitcher 5 is pressed by the knurled roller 24 to form a plurality of air vent grooves 27 on the outer surface of the strip rubber 17 (grooves). Attaching process). The strip rubber 17 is sequentially pressed by the pressure roller 4 and is wound while being overlapped in half in the width direction. However, the formed air vent groove 27 can be smoothly discharged without leaving air in the overlapping portion.

  When the first wound body 28 is obtained, the movement of the rubber supply unit 3 in the axial direction of the drum 2 is temporarily stopped. At this time, the knurled roller 24 of the stitcher 5 is separated from the strip rubber 17 and the creation of the air bleeding groove 27 on the outer surface of the strip rubber 17 is stopped. Then, the tread rubber 8 is wound around the same circumference in the tire radial direction with the other side edge position of the strip rubber 17 and the side edge position on the surface side of the tread rubber 8 matched.

  As shown in FIG. 7, the feed direction of the rubber supply unit 3 is reversed, and the drum is wound spirally by moving at a predetermined feed speed toward the other side (downward in the figure) of the drum 2 in the axial direction. (The feed rate may be determined so that the feed amount at this time is also half the width of the strip rubber 17 as described above.) At this time, the knurled roller 24 of the stitcher 5 is pressed against at least a portion covered by the strip rubber 17 to be wound from the previously wound strip rubber 17. Here, the air vent groove 27 is formed in the half of the strip rubber 17 on the winding direction side, but it may be formed on the whole. As a result, air does not remain in the overlapping portion between the portion wound first and the portion wound next. The strip rubber 17 is wound to a position that covers at least the first wound body 28 beyond the boundary position B between the tread rubber 8 and the case body 7. Here, the strip rubber 17 is wound up to the side edge 12 a of the outer surface of the rim strip rubber 12. Thereby, the 2nd volume body 29 which covers the 1st volume body 28 is obtained (2nd volume process). Thus, the remaining of air can be effectively prevented even in the second winding step.

  In this manner, as shown in FIG. 4, the rubber tire is completed by winding the strip rubber 17 around the tire case 6 in a so-called J shape to obtain the sidewall rubber 26. A pneumatic tire is obtained by setting the completed green tire in a mold of a vulcanizing mold and vulcanizing and molding.

The green tire formed by the sidewall forming process has the following characteristics.
(1) Since the central portion C having the largest thickness of the strip rubber 17 is made to coincide with the boundary position B between the tread rubber 8 and the case main body 7 of the tire case 6, it is wound once so that the air to this portion is Prevents the embrace and suppresses air entry.
(2) Since the air vent groove 27 extending in the tire circumferential direction is formed on the outer surface of the strip rubber 17 when forming the sidewall rubber 26, either the first wound body 28 or the second wound body 29 is formed. Even in this case, the entry of air between the strip rubbers 17 can be suppressed.

  In addition, this invention is not limited to the structure described in the said embodiment, A various change is possible.

  In the above embodiment, only the air bleeding groove 27 extending in the tire circumferential direction is formed by the knurled roller 24 of the stitcher 5, but by forming the protrusions 24b in a lattice shape or the like, not only in the tire circumferential direction but also in the tire You may make it form the air bleeding groove 27 extended also in the width direction. The air vent groove 27 extending in the tire width direction does not need to be orthogonal to the air vent groove 27 extending in the tire circumferential direction, and may intersect diagonally.

  In the above-described embodiment, the feed speed of the strip rubber 17 is determined so that a constant feed amount can be obtained. However, every time the drum 2 rotates one time (for example, the width dimension of the strip rubber 17). (A value of 1/2) may be shifted.

  In the above-described embodiment, the strip rubber 17 is wound with the same feed amount. However, the strip rubber 17 may be appropriately changed according to a difference in the thickness of the sidewall rubber 26. For example, if the tire outer diameter side is more than the boundary position B between the tread rubber 8 and the case body 7, the feed amount of the strip rubber 17 wound around the first wound body 28 is set larger, and if the tire inner diameter side, the reverse is performed. It may be set to a small value.

  In the above-described embodiment, the first and second wound bodies 28 and 29 are formed by one strip rubber 17, but each may be formed by a separate strip rubber 17. . In this case, the strip rubbers 17 may be made of the same material or different materials. In addition, the second wound body may be formed after forming the first wound body, but the second wound body is formed while forming the first wound body in order to shorten the process time. May be. That is, if the second wound body is formed on the outer surface side of the first wound body, for example, the winding of the second wound body may be started before the winding of the first wound body is completed. Then, the winding of the first winding body and the winding of the second winding body may be started simultaneously.

  In the above-described embodiment, the first and second wound bodies are formed by folding the strip rubber 17 only once, but the second wound body can be formed by folding twice or more times. Further, a wound body may be formed on the outer side.

  In the embodiment, when the sidewall rubber 26 is formed, the strip rubber 17 is wound from the case body 7 side to the tread rubber 8 side and then wound from the tread rubber 8 side to the case body 7 side. Conversely, it may be performed. That is, the starting point is the same at the boundary position B between the tread rubber 8 and the case main body 7, but after the strip rubber 17 is wound from the tread rubber 8 side to the case main body 7 side, the tread rubber from the case main body 7 side is obtained. You may make it wind around 8 side.

  In this case, as shown in FIG. 8, it is preferable to form a rubber member 30 as a part of the side wall rubber 26 in advance in the side portion 14 of the case body 7 in the tire case 6. However, the entire sidewall rubber 26 can be formed by winding the strip rubber 17 without providing the rubber member 30.

  In the first winding step, the strip rubber 17 is wound once along the boundary position B, and then, as shown in FIG. 9, from the boundary position B between the tread rubber 8 and the case body 7, the tire inner diameter (in the drawing) The first wound body 28 is formed by spirally winding the rubber member 30 toward the lower side. When the first wound body 28 is formed, the air bleeding groove 27 is formed on the outer surface of the strip rubber 17 to be first attached by the knurled roller 24 of the stitcher 5 as in the above embodiment.

  In the second winding step, as shown in FIG. 10, the strip rubber 17 is moved from the rubber member 30 side to at least the boundary position B between the tread rubber 8 and the case body 7 to cover the first wound body 28. The second wound body 29 is formed by winding in a spiral. Here, the strip rubber is wound up to the upper end edge of the tread rubber 8. Also in the second winding step, as in the case of the first winding step, the knurled roller 24 of the stitcher 5 is pressed against at least a portion of the strip rubber 17 that has been wound earlier that is covered by the strip rubber 17 that is to be wound from now on. An air vent groove 27 is formed in advance. As a result, air does not remain in the overlapping portion between the portion wound first and the portion wound next.

  In this way, as shown in FIG. 8, the rubber strip 26 is wound around the tire case 6 in a so-called inverted J shape to obtain the sidewall rubber 26, thereby completing the green tire. A pneumatic tire is obtained by setting the completed green tire in a mold of a vulcanizing mold and vulcanizing and molding.

DESCRIPTION OF SYMBOLS 1 ... Side wall formation apparatus 2 ... Drum 3 ... Rubber supply part (supply means)
DESCRIPTION OF SYMBOLS 4 ... Pressure roller 5 ... Stitcher 6 ... Tire case 7 ... Case main body 8 ... Tread rubber 9 ... Bead core 10 ... Carcass ply 11 ... Inner liner 12 ... Rim strip rubber 13 ... Crown part 14 ... Side part 15 ... Belt 16 ... Belt reinforcement Layer 17 ... Strip rubber 18 ... Base 19 ... Die 20 ... Cylinder 21 ... Piston 22 ... Cylinder 23 ... Piston 24 ... Giza roller 25 ... Tread ring 26 ... Side wall rubber 27 ... Air vent groove 28 ... First winding body 29 ... No. Rolled body 30 ... Rubber member

Claims (6)

A case body having a crown portion constituting an outer peripheral portion and side portions constituting both side surface portions and provided with a tread rubber on an outer periphery of the crown portion, a band-like shape on the side portion and a part of the tread rubber. A side wall forming step of forming at least a part of the side wall rubber by winding the strip rubber of
The sidewall forming step includes
A first winding step of forming a first wound body by winding the strip rubber toward the other remaining from either the tread rubber or the case body;
A second winding step of winding the strip rubber around the outer surface of the first winding body to form a second winding body;
A grooving step of forming an air vent groove on the outer surface of the strip;
A method for manufacturing a pneumatic tire, comprising:   The said 2nd winding body is formed in the said 2nd winding process, The said 2nd winding body is formed by folding and winding the strip rubber which formed the said 1st winding body around the outer surface of the said 1st winding body. Method of manufacturing a pneumatic tire. In the first winding step, the first wound body is formed so as to cover an end portion of the tread rubber by winding the strip rubber a plurality of times.
In the second winding step, the direction in which the strip rubber is wound is folded back in the opposite direction, and the second wound body is formed by winding a plurality of times until at least the boundary position between the tread rubber and the case body is exceeded. Item 3. A method for manufacturing a pneumatic tire according to Item 1 or 2.   The pneumatic tire manufacturing method according to any one of claims 1 to 3, wherein in the grooving step, a knurling process is performed on an outer surface of the strip rubber by the stitcher. The strip rubber has a cross-sectional shape whose thickness decreases toward both ends in the width direction,
In the first winding step, the center position in the width direction of the strip rubber and the boundary position between the tread rubber and the case body are made to coincide with each other, and the first turn is wound in parallel with the boundary position. 5. The method for producing a pneumatic tire according to any one of 4. A drum having a crown portion constituting an outer peripheral portion and side portions constituting both side surface portions, and holding a case main body provided with a tread rubber on an outer periphery of the crown portion;
Drive means for rotationally driving the drum;
Supply means for supplying a strip-shaped strip rubber to the side portion and a part of the tread rubber;
A stitcher that forms an air vent groove on the outer surface of the strip rubber that wraps the strip rubber around the case body;
Moving means for moving the supply means relative to the drum in the axial direction of the drum;
Control means for forming an air bleeding groove on the outer surface of the strip rubber by wrapping a strip rubber around the outer surface of the case body by driving and controlling the driving means and the moving means, and driving the stitcher.
A pneumatic tire manufacturing apparatus.

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