Low cover molding device and tire manufacturing method

Abstract

To provide a low cover forming device and a tire manufacturing method that prevents cavities from being formed in the tire forming member by the elastic force of the bead apex during the generation of the low cover.SOLUTION: The low cover forming device 1 is equipped with a drum 10, a turn-up bladder, and a pressing roller. Before the ends of the inner liner 51 and carcass ply 52a, which are wrapped around the drum 10, are folded back, the joint 51a of the inner liner 51 is pressed by the pressure roller. The position where the pressure is applied is set to be inside the tip of the bead apex. This prevents the inner liner 51 and the carcass plies, which are adhered near the joint, from being pulled apart by the elastic force SF.SELECTED DRAWING: Figure 6

Description

[Technical Field]

[0001] The present invention relates to a raw cover molding device and a tire manufacturing method. [Background technology]

[0002] Japanese Patent Application Laid-Open Publication No. 2016-210017 discloses a method for manufacturing a pneumatic tire. The manufacturing method disclosed therein includes a first cover forming step, a tread reinforcing layer forming step, a holding step, and a joining step.

[0003] Among these, the first cover forming process is a process of forming a cylindrical first cover including a carcass cylinder on a cylindrical first drum, on which a sheet-like carcass ply is wound and on which bead cores are attached at both ends. The tread reinforcing layer forming process is a process of forming a cylindrical tread reinforcing layer on which a sheet-like reinforcing cord ply is wound, on a cylindrical second drum. The holding process is a process of holding the tread reinforcing layer removed from the second drum concentrically at a standby position radially outward of the first cover. The joining process is a process of forming a first cover joined body in which the outer surface of the first cover is pressed against the entire inner surface of the held tread reinforcing layer by shaping the first cover into a toroidal shape between the bead cores by injecting internal pressure.

[0004] The method for manufacturing a pneumatic tire disclosed in the publication is characterized by forming tread rubber by directly spirally winding a tape-like rubber strip around the outer surface area, including the tread reinforcing layer, of the shaped first cover assembly.

[0005] Japanese Patent Application Laid-Open Publication No. 2019-81300 discloses a tire building apparatus. The tire building apparatus disclosed in the publication includes a tire building pressure roller that moves laterally across the width of the former to press and crimp the joint portion formed by overlapping both ends of a rubber member wrapped around the former. According to the publication, the tire building apparatus uses the pressure roller to press and crimp the joint portion. This is said to prevent the rubber member from opening or air from entering, even if there is a step in the former, for example. [Prior art documents] [Patent documents]

[0006] [Patent Document 1] Japanese Patent Application Laid-Open No. 2016-210017 [Patent Document 2] JP 2019-81300 A Summary of the Invention [Problem to be solved by the invention]

[0007] The molding of the low cover involves a process in which the carcass ply is expanded between the bead cores by inflating it with internal pressure, forming a toroidal shape. During this process, air can get trapped in the joints of the inner liner. If air gets trapped in the joints of the inner liner, it can cause defects in the shape of the low cover or render the tire unsuitable. This can result in reduced tire yields.

[0008] The inventors would like to improve the tire yield resulting from molding the raw cover. [Means for solving the problem]

[0009] The raw cover molding device disclosed herein includes a cylindrical drum, turn-up bladders provided on both axial sides of the drum, a pressure roller facing the outer peripheral surface of the drum and configured to be movable in the axial direction, and a control device. The control device is configured to execute a process in which the pressure roller presses the joint portion of the inner liner and the carcass ply layered on the outer peripheral surface of the drum before the turn-up bladders fold back an inner liner having a joint portion wrapped around the outer peripheral surface of the drum and both end portions of a carcass ply layered on the inner liner to wrap around a bead apex. In the process in which the pressure roller presses the inner liner and the carcass ply layered on the outer peripheral surface of the drum, the position at which the pressure roller presses the inner liner and the carcass ply layered on the outer peripheral surface of the drum is set to a predetermined position inside the position where the tip of the bead apex will be located when the both end portions of the inner liner and the carcass ply are folded back by the turn-up bladders. [Effects of the Invention]

[0010] The raw cover molding device disclosed herein can improve tire yields resulting from the molding of raw covers. [Brief explanation of the drawings]

[0011] [Figure 1] FIG. 1 is a cross-sectional view showing the cross-sectional structure of a tire 500. As shown in FIG. [Figure 2] FIG. 2 is a schematic diagram of a raw cover molding system 100. [Figure 3] FIG. 3 is a cross-sectional view of the raw cover molding device 1. As shown in FIG. [Figure 4] FIG. 4 is a schematic diagram of the turn-up bladder 40 and its surroundings of the raw cover molding apparatus 1. As shown in FIG. [Figure 5] FIG. 5 is a perspective view showing the roller device 60 and the drum 10. As shown in FIG. [Figure 6]FIG. 6 is a cross-sectional view of the inner liner 51 and the carcass ply 52a wound around the drum 10, as viewed from the axial direction of the drum 10. As shown in FIG. [Figure 7] FIG. 7 is a cross-sectional view showing the pressing step. [Figure 8] FIG. 8 is a view showing the vicinity of the bead 58 after it has been turned up. DETAILED DESCRIPTION OF THE INVENTION

[0012] A raw cover molding device according to one embodiment will be described below with reference to the drawings. Note that the present invention is not limited to the following embodiment. Each drawing is a schematic representation and does not necessarily reflect the actual product. Each drawing shows only an example and does not limit the present invention unless otherwise specified. Furthermore, components and parts that perform the same function are appropriately designated by the same reference numerals, and duplicate explanations will be omitted.

[0013] <Tire 500> FIG. 1 is a cross-sectional view showing the cross-sectional structure of a tire 500. FIG. 1 shows only the right half of the tire 500 as viewed from the drawing. Since the tire 500 is bilaterally symmetrical, a description of the left half of the tire 500 will be omitted here. FIG. 1 shows a cross section along the width direction of a tread portion 510 of the tire 500. The tire 500 is formed by vulcanizing and integrating a raw cover, which is an unvulcanized tire made up of a combination of multiple unvulcanized rubber members, and then molding an outer shape such as a tread pattern.

[0014] FIG. 1 illustrates a cross section of a tire after vulcanization molding, but for convenience, the boundaries of the rubber components before vulcanization are depicted so that the boundaries of the components that make up the tire 500 in the low cover before vulcanization can be seen. The boundaries of the components that make up the tire 500 in the low cover before vulcanization are integrated after vulcanization. Also, to make the drawing easier to understand, some hatching has been omitted. Note that FIG. 1 merely illustrates one embodiment of a tire, and unless otherwise specified, the structure of the tire is not limited to the form shown in FIG. 1. Furthermore, the arrangement of each component and the order in which they are combined may be changed unless otherwise specified.

[0015] In the form shown in FIG. 1, the tire 500, in a low cover state, includes an inner liner 51, a carcass 52, a cushion rubber 53, a breaker 54, an undertread rubber 55, a tread rubber 56, a sidewall rubber 57, beads 58, and a chafer 59.

[0016] The inner liner 51 is a rubber sheet layer placed inside the tire cords and is a component for ensuring the airtightness of the pneumatic tire. The carcass 52 has at least one carcass ply. In this embodiment, the carcass 52 has a carcass ply 52a and a carcass ply 52b. The carcass ply 52a and the carcass ply 52b form a layer.

[0017] Beads 58 are disposed at both widthwise ends of the inner liner 51 and the carcass 52. Both widthwise ends of the inner liner 51 and the carcass 52 are folded back so as to cover the beads 58.

[0018] The cushion rubber 53, breaker 54, undertread rubber 55, tread rubber 56, and sidewall rubber 57 are wound around predetermined positions of the toroidally molded inner liner 51 and carcass 52. Then, the shape of the joints of the rubber material is adjusted to produce a raw cover, which is an unvulcanized tire.

[0019] The tread rubber 56 is a rubber member that constitutes the tread portion 510, which is the portion that comes into contact with the ground during running. The tread rubber 56 is a rubber layer that is attached to the outer peripheral surface of the row cover and has a required thickness. The breaker 54 is an arranged cord layer.

[0020] The breaker 54 absorbs shocks from the road surface and prevents external damage to the tread rubber 56 from reaching the carcass 52 directly, and also serves to prevent separation between the tread rubber 56 and the carcass 52.

[0021] The cushion rubber 53 is disposed at the edge of the breaker 54 between the breaker 54 and the carcass 52. The cushion rubber 53 acts as a buffer material that reduces the force that the edge of the breaker 54 receives from acting on the carcass 52.

[0022] The undertread rubber 55 is disposed between the tread rubber 56 and the breaker 54. In this embodiment, the undertread rubber 55 is provided particularly so as to cover the edge portion of the breaker 54, and acts as a buffer material that reduces the force that the edge portion of the breaker 54 receives from acting on the tread rubber 56.

[0023] The bead 58 is located axially inward of the sidewall rubber 57. The bead 58 includes a bead core 58a and a bead apex 58b. The bead core 58a is formed, for example, by winding a large number of steel bead wires. The bead apex 58b is located radially outward of the tire 500 relative to the bead core 58a. The bead apex 58b is a member formed from a rubber composition having a certain degree of rigidity. The bead apex 58b is tapered radially outward of the tire 500 and has a substantially triangular cross section.

[0024] The chafer 59 is located axially inward of the bead 58. The chafer 59 is a portion that comes into contact with the rim of the wheel on which the tire 500 is mounted, and is a member that protects the carcass plies 52a, 52b from friction with the rim. The chafer 59 is formed, for example, from cloth and rubber impregnated into the cloth. The chafer 59, together with the inner liner 51, forms the inner surface of the tire 500.

[0025] Here, the low cover is formed by molding and assembling cylindrical first and second covers, and then shaping the first cover into a toroidal shape and expanding it. The first cover is a cylindrically formed component having inner liner 51 and carcass plies 52a, 52b shown in FIG. 1. Beads 58 and chafers 59 are attached to the first cover. When inner liner 51 and other components are molded into a cylindrical shape, the first cover is pressed at predetermined positions by rollers or the like, and both ends are turned up. The second cover is a component having tread rubber 56, breaker 54, cushion rubber 53, and undertread rubber 55.

[0026] Fig. 2 is a schematic diagram of the raw cover molding system 100. As shown in Fig. 2, the raw cover is molded by a raw cover molding device 1 incorporated in the raw cover molding system 100. Fig. 2 illustrates an inner liner 51 wound around a drum 10. Fig. 3 is a cross-sectional view of the raw cover molding device 1.

[0027] <Low cover molding system 100> As shown in Figure 2, the low cover molding system 100 includes a low cover molding device 1 and an external server device 200. The low cover molding device 1 and the external server device 200 are connected wirelessly via a network NW. The network NW is configured by the Internet and various mobile communication systems established by wireless base stations (not shown). Note that the low cover molding device 1 and the external server device 200 may also be connected by wire.

[0028] <Low cover molding device 1> The raw cover molding device 1 molds the above-mentioned raw cover. As shown in Figures 2 and 3, the raw cover molding device 1 includes a pair of drums 10, a gap adjustment mechanism 20, a bead holding unit 30, a turn-up bladder 40, a roller device 60 (see Figure 5), a rail 70 (see Figure 5), and a control device 90 (see Figure 2). The raw cover molding device 1 may include, for example, a device for kneading rubber material, a device for assembling tire components, a vulcanizing device, and the like, but descriptions of these will be omitted here.

[0029] <50 cylindrical parts> When molding the low cover, as shown in FIG. 3, a cylindrical part 50 including an inner liner 51 (see FIG. 4) and carcass plies 52a, 52b (see FIG. 4) is prepared. The cylindrical part 50 is a cylindrical member that forms the inner layer of the low cover. The inner liner 51 forms the inner surface of the cylindrical part 50. The carcass ply 52a is arranged on the outside of the inner liner 51, and the carcass ply 52b is arranged on the outside of the carcass ply 52a. The carcass ply 52a is formed to be longer in the axial direction of the drum 10 than the inner liner 51. A bead 58 is attached to the cylindrical part 50.

[0030] <Drum 10> As shown in FIG. 3, the drum 10 is a cylindrical member that supports the cylindrical part 50 from the inside. A sheet-like inner liner 51 (see FIG. 4) and carcass plies 52a, 52b (see FIG. 4) are wound around the drum 10. The inner liner 51 and the carcass plies 52a, 52b have a sheet-like shape with a longitudinal direction perpendicular to the axial direction of the drum 10 in a plan view. The cylindrical part 50 is formed by winding the inner liner 51 and the carcass plies 52a, 52b around the drum 10. The pair of drums 10 are provided at positions spaced apart from each other in the axial direction.

[0031] As shown in FIG. 3, the drum 10 includes a body portion 11, a grip plate 13, a support cylinder 14, and a guide plate 15. The drum 10 is provided with a bead holding portion 30. The body portion 11 is cylindrical in shape. The body portion 11 supports various components of the drum 10. A screw shaft 21, which will be described later, is inserted into the body portion 11. A pair of drums 10 are connected to the same screw shaft 21 via the body portions 11.

[0032] <Body 11> A grip plate 13 and a guide plate 15 are attached to the outer peripheral surface of the body 11. In the axial direction of the body 11, the grip plate 13 is attached to the outside, and the guide plate 15 is attached to the inside. The grip plate 13 and the guide plate 15 are each formed in a substantially disk shape. A cylindrical support cylinder 14 extends axially outward from the outer radial end of the grip plate 13. A space is formed radially inward on the axially outer surface of the guide plate 15. The grip plate 13 and the guide plate 15 are attached with a gap between them in the axial direction. A bead holding portion 30 is provided between the grip plate 13 and the guide plate 15.

[0033] <Bead holding portion 30> The bead holding portion 30 is a portion that holds the bead 58 via the cylindrical part 50. When the cylindrical part 50 is set on the drum 10, the bead 58 is transported inward from both axial ends of the cylindrical part 50. The bead 58 is attached to a predetermined position on the cylindrical part 50. A bead holding portion 30 is provided on each of the pair of drums 10. The bead holding portion 30 includes a piston ring 31 and a lock segment 32. The lock segment 32 is a ring-shaped member. The lock segment 32 expands radially outward and is pressed against the inner circumferential surface of the cylindrical part 50. A portion of the outer circumferential surface of the lock segment 32 is pressed against the position of the cylindrical part 50 where the bead 58 is attached. The lock segment 32 includes an elastic ring 32a at the portion that is pressed against that position.

[0034] <Lock Segment 32> The lock segment 32 has an inclined surface 32b on the axially inner side. The inclined surface 32b is formed from the radially inner side toward the radially outer side. A piston ring 31 is provided between the inclined surface 32b of the lock segment 32 and a space formed inside the guide plate 15. The piston ring 31 is formed in an annular shape. The piston ring 31 has an inclined surface 31a on the axially outer side that corresponds to the inclined surface 32b of the lock segment 32. The piston ring 31 is configured to be driven in the axial direction by a driving device (not shown). When the piston ring 31 is driven axially outward, the inclined surface 32b of the lock segment 32 slides against the inclined surface 31a of the piston ring 31. The lock segment 32 moves radially outward. As a result, the bead retaining portion 30 is pressed against the cylindrical part 50 to retain the bead 58.

[0035] <Space adjustment mechanism 20> As shown in FIG. 3, the gap adjustment mechanism 20 adjusts the axial gap between the pair of drums 10. When molding the raw cover, the gap adjustment mechanism 20 narrows the gap between the pair of drums 10, thereby folding both ends of the cylindrical part 50 inward in the axial direction. The gap adjustment mechanism 20 is composed of a screw shaft 21, a threaded hole 22 formed in the body portion 11, and a motor 23. The screw shaft 21 has a male thread on its outer circumferential surface. Both ends of the screw shaft 21 are supported by bearings 24. One end of the screw shaft 21 is connected to the motor 23. The motor 23 is electrically connected to and controlled by a control device 90 (see FIG. 1). The screw shaft 21 is inserted into the cylindrical body portion 11. The body portion 11 is formed with a threaded hole 22 through which the screw shaft 21 is inserted. The threaded hole 22 is a threaded hole that penetrates the body portion 11 in the axial direction. The threaded hole 22 has a female thread that matches the outer circumferential surface of the screw shaft 21. The screw hole 22 and the screw shaft 21 are engaged with each other.

[0036] <Screw shaft 21> The screw shaft 21 is rotated by a motor 23 connected to one end. The threaded hole 22 and the screw shaft 21 are engaged, so that the body 11 moves in the axial direction of the screw shaft 21 in conjunction with the rotation of the screw shaft 21. In this embodiment, the male thread of the screw shaft 21 is wound in opposite directions on one body 11 side and the other body 11 side. Therefore, by changing the direction of rotation of the motor 23, the distance between the pair of drums 10 can be adjusted, widened or narrowed.

[0037] <Turn Up Bladder 40> The turn-up bladders 40 are components used to fold back both ends of the cylindrical part 50 during molding of the lower cover. The turn-up bladders 40 are provided on both axial sides of the drum 10. In this embodiment, the turn-up bladders 40 are positioned axially outward of the bead holding portions 30. The turn-up bladders 40 are made of rubber and formed as a continuous tube in the circumferential direction of the grip plate 13. The turn-up bladders 40 are supported by support portions 13a provided on the outer peripheral surface of the grip plate 13. The support portions 13a are provided continuously in the circumferential direction of the grip plate 13. The support portions 13a are provided on the inner and outer axial sides of the cylindrical part 50 and support the inner and outer axial ends of the turn-up bladder 40, respectively. A hole (not shown) is formed in the grip plate 13 between the inner and outer support portions 13a. The hole is configured to allow gas to be filled inside. Before being filled with gas, the turn-up bladder 40 is folded and tilted outward in the axial direction. Before being filled with gas, the turn-up bladder 40 is disposed on the outer circumferential surface of the support cylinder 14.

[0038] As shown in Figure 4, this embodiment is provided with a pressing member 16 that presses the expanded turn-up bladder 40 from the outside in the axial direction. Figure 4 is a schematic diagram of the area around the turn-up bladder 40 of the raw cover molding device 1. The pressing member 16 is provided on the outside of the drum 10 in the axial direction relative to the turn-up bladder 40. The pressing member 16 has a disk-shaped pressing surface that comes into contact with the turn-up bladder 40. When the turn-up bladder 40 expands, the pressing member 16 moves inward from both axial ends, pressing the turn-up bladder 40 against the cylindrical part 50.

[0039] <Roller device 60> FIG. 5 is a perspective view showing a roller device 60 and a drum 10. As shown in FIG. 5, the roller device 60 is disposed at a position facing the outer peripheral surface of the drum 10. The roller device 60 includes a cylinder 61, a support member 62, and a pressure roller 63. The roller device 60 is disposed movably along a rail 70 extending along the axial direction of the drum 10. The roller device 60 is configured so that the pressure roller 63 can contact and separate from the drum 10 in the radial direction of the drum 10. In this embodiment, two roller devices 60 are disposed along the rail 70. However, the number of roller devices 60 is not particularly limited. There may be one roller device 60, or three or more roller devices 60. Note that FIG. 5 shows a state in which the inner liner 51 is wound around the drum 10, and further the carcass ply 52a is wound thereon. However, the following description also applies to a case in which the carcass ply 52b is wound over the carcass ply 52a.

[0040] <Cylinder 61> The cylinder 61 is mounted movably along the rail 70. Driving the cylinder 61 causes the rod 61a to extend and retract. The cylinder 61 is disposed so that the longitudinal direction of the rod 61a is substantially aligned with the radial direction of the drum 10. Therefore, the rod 61a extends and retracts in the radial direction of the drum 10. A support member 62 is attached to one of the ends of the rod 61a, closer to the drum 10. When the rod 61a extends, the support member 62 moves closer to the drum 10. When the rod 61a retracts, the support member 62 moves away from the drum 10. The cylinder 61 is a linear motion mechanism and may be implemented, for example, by a double-acting single-rod cylinder. Note that the type of cylinder used is not particularly limited. The cylinder 61 may be configured as an air cylinder, an electric cylinder, a hydraulic cylinder, or the like. In this embodiment, the cylinder 61 includes three rods 61a. However, the number of rods 61a is not particularly limited.

[0041] <Support member 62> The support member 62 is a member that supports the pressure roller 63. The support member 62 is connected to the tip of the rod 61a. The support member 62 supports the pressure roller 63 so that the axial direction of the pressure roller 63 is aligned with the axial direction of the drum 10. The support member 62 also supports the pressure roller 63 rotatably.

[0042] <Pressure roller 63> The pressure roller 63 is a member that comes into contact with the carcass ply 52a and presses the carcass ply 52a. As the cylinder 61 moves along the rail 70, the pressure roller 63 moves along the rail 70. That is, the pressure roller 63 is configured to be movable in the axial direction of the drum 10. When the rod 61a extends, the pressure roller 63 presses the carcass ply 52a wound around the drum 10. In this embodiment, the pressure roller 63 is configured to press the carcass ply 52a, thereby pressing the joint portion of the inner liner 51. The material for forming the pressure roller 63 is not particularly limited, but it may be, for example, a knurled cylindrical member made of iron. In this embodiment, the pressure roller 63 has a length of 20 mm in the axial direction of the drum 10. However, the size of the pressure roller 63 is not limited to this. Furthermore, the center of the pressure roller 63 and the center of the cylinder 61 are aligned in the radial direction of the drum 10.

[0043] <Rail 70> The configuration of the rail 70 is not particularly limited, but for example, the rail 70 includes a pulley (not shown), a belt (not shown) wound around the pulley, and a motor (not shown) connected to the pulley. The lower part of a cylinder 61 is connected to the belt. When the motor is driven, the pulley rotates and the belt runs. When the belt runs, the cylinder 61 moves along the rail 70. That is, the roller device 60 moves along the rail 70. However, the roller device 60 may also be manually moved along the rail 70. The rail 70 extends in the axial direction of the drum 10 and is formed to have approximately the same axial length as the drum 10 in the axial direction. The rail 70 may be shorter or longer than the drum 10 in the axial direction of the drum 10.

[0044] <Control device 90> The control device 90 shown in FIG. 2 is a device that performs various processes in the raw cover molding apparatus 1. The control device 90 is electrically connected to and controls the drum 10, the gap adjustment mechanism 20, the turn-up bladder 40, the roller device 60, and the rails 70. The control device 90 may be implemented by a computer running a predetermined program. Specifically, each function of the control device 90 is processed by the arithmetic unit (also referred to as a processor, central processing unit (CPU), or microprocessing unit (MPU)) and storage device (memory, hard disk, etc.) of each computer that constitutes the control device 90. For example, each component of the control device 90 may be implemented as, or as part of, a database that stores data implemented by a computer in a predetermined format, a data structure, or a processing module that performs predetermined arithmetic processing according to a predetermined program. Although not shown, the control device 90 may be implemented by multiple control devices working together. For example, if the control device 90 of the raw cover molding apparatus 1 is connected to an external computer via a LAN cable, the Internet, or the like so as to enable data communication with the external computer, the processing of the control device 90 may be performed in cooperation with such an external computer. For example, the information stored in the control device 90 or a portion of the information may be stored by the external computer, and the processing or a portion of the processing performed by the control device 90 may be performed by the external computer. Each processing performed by the control device 90 will be described later.

[0045] In this embodiment, the control device 90 is wirelessly connected to the external server device 200 via a network NW. The network NW is configured by the Internet, various mobile communication systems constructed by wireless base stations (not shown), and the like.

[0046] The external server device 200 is configured, for example, by a general-purpose computer. The external server device 200 is accessed by the control device 90 via, for example, a web browser. The external server device 200 includes a storage device 210. The storage device 210 has a non-volatile storage area. The storage device 210 stores size data of the tire 500 (see FIG. 1 ). The size data of the tire 500 is data related to dimensions required when molding the tire 500. The size data of the tire 500 includes, for example, data on the distance between the center of the tire 500 and the bead apex 58b and data on the height of the bead apex 58b. The external server device 200 may be, for example, a cloud server.

[0047] The configuration of the raw cover molding system 100 in this embodiment has been described above. Next, a manufacturing method for a tire 500 (see FIG. 1) realized by the raw cover molding device 1 will be described.

[0048] Here, the manufacturing of the tire 500 includes the following steps. Step A: A step of winding the inner liner 51 around the outer periphery of the drum 10 and joining the ends of the inner liner 51 (see FIG. 2). Step B: A step of overlapping the carcass plies 52a and 52b onto the inner liner 51 wound around the outer periphery of the drum 10. Step C: A step of arranging the bead core 58a and the bead apex 58b at predetermined positions on both ends of the carcass plies 52a and 52b. Step D: After the carcass plies 52a, 52b are overlapped on the inner liner 51, a pressing step is performed in which a pressing roller 63 is pressed against the joint portion 51a of the inner liner 51 at a predetermined position inside the position where the tip of the bead apex 58b will be located when the bead apex 58b is folded back, before the turn-up bladder 40 folds back both ends of the inner liner 51 and the carcass plies 52a, 52b and the bead apex 58b are folded back (see FIG. 5).

[0049] In steps A and B, the inner liner 51 and the carcass ply 52a are wound around the drum 10. In these steps, the inner liner 51 and the carcass ply 52a are wound around the drum 10 and formed into a cylindrical shape. The inner liner 51 and the carcass ply 52a are supplied to the drum 10 by, for example, a servicer (not shown), and are wound around the drum 10 by rotating the drum 10. The inner liner 51 and the carcass ply 52a are preferably supplied so that the center in the width direction of the inner liner 51 and the carcass ply 52a coincides with the center in the axial direction of the drum 10. In step A, after the inner liner 51 is wound around the drum 10, a pressing roller 63 may be pressed against the joint portion 51a of the inner liner 51. Although not shown, in step B, after the carcass ply 52a is wound around the drum 10, a pressing roller 63 may be pressed against the joint portion (not shown) of the carcass ply 52a.

[0050] In step A, the inner liner 51 is cut to a length just suitable for winding around the drum 10 and supplied to the drum 10. The joint portion 51a of the inner liner 51 on the drum 10 refers to the portion where the front end 51F (see FIG. 6) and the rear end 51Rr (see FIG. 6) of the inner liner 51 wound around the drum 10 overlap. FIG. 6 is a cross-sectional view of the inner liner 51 and the carcass ply 52a wound around the drum 10, as viewed from the axial direction of the drum 10. FIG. 6 shows a cross-section of the joint portion 51a of the inner liner 51. The "front end of the inner liner 51" refers to the end of the inner liner 51 in the longitudinal direction that is wound around the drum 10 first. The "rear end of the inner liner 51" refers to the end of the inner liner 51 in the longitudinal direction that is wound around the drum 10 last. The joint portion 51a of the inner liner 51, where the end portion of the inner liner 51 is overlapped, has a greater thickness in the radial direction of the drum 10 than other portions of the inner liner 51. For this reason, when the carcass ply 52a is wound overlapping the inner liner 51 in step B, a void CV may be formed between the inner liner 51 and the carcass ply 52a at the joint portion 51a of the inner liner 51, as shown in Fig. 6. The void CV may be a location into which air that has entered through the joint portion 51a seeps when the raw cover is inflated in the shaping step as shown in Fig. 1.

[0051] <Press process> Fig. 7 is a cross-sectional view showing the pressing step. As shown in Fig. 7, the pressing step is a process of pressing a pressing roller 63 against the joint portion 51a of the inner liner 51 before the inner liner 51 and the carcass plies 52a, 52b are folded back. By this pressing step, the pressing roller 63 is pressed against the joint portion 51a, so that the inner liner 51 and the carcass ply 52a can be pressure-bonded together at the joint portion 51a. Therefore, even if a void CV occurs between the inner liner 51 and the carcass ply 52a at the joint portion 51a of the inner liner 51, the void CV disappears.

[0052] This pressing step is preferably performed after the carcass plies 52a, 52b are overlapped on the inner liner 51 and before both end portions of the inner liner 51 and the carcass plies 52a, 52b and the bead apex 58b are turned up by the turn-up bladder 40. This pressing step may be performed before or after the bead core 58a and the bead apex 58b are disposed at predetermined positions on both end portions of the carcass plies 52a, 52b. In addition, in this pressing step, the position against which the pressing roller 63 is pressed is preferably set to a predetermined position inside the position at which the tip of the bead apex will be disposed when the bead apex is turned up.

[0053] This pressing step can be realized, for example, by control by a control device 90. The control device 90 drives the cylinder 61 of the roller device 60 shown in FIG. 7 to extend the rod 61a in the radial direction of the drum 10, thereby pressing the pressing roller 63 against the carcass ply 52a. Note that the drum 10 may be rotated in advance so that, when pressing the pressing roller 63, the joint portion 51a (see FIG. 6) of the inner liner 51 is positioned opposite the pressing roller 63 in the radial direction of the drum 10. Furthermore, the pressing by the pressing roller 63 in the pressing step may be controlled, for example, so as to generate a predetermined pressure on the carcass ply 52a.

[0054] Furthermore, the control device 90 is preferably configured to execute the following acquisition process and positioning process.

[0055] <Acquisition process> The acquisition process is a process for acquiring data on the size of the tire 500 to be molded. In this embodiment, when molding the low cover of the tire 500, the control device 90 acquires the data on the size of the tire 500 from the storage device 210 of the external server device 200 via the network NW shown in FIG.

[0056] <Positioning process> The positioning process is a process for determining the position where the pressure roller 63 is pressed against the inner liner 51 and carcass ply 52a stacked on the outer periphery of the drum 10, based on the size data of the tire 500 acquired by the acquisition process. The position where the pressure roller 63 is pressed against the inner liner 51 and carcass ply 52a stacked on the outer periphery of the drum 10 is set to be inside the tip end 58ba of the bead apex 58b. The determination of the position where the pressure roller 63 is pressed will be described below. Note that each position acquired by the positioning process can be acquired, for example, by coordinates on the raw cover molding device 1.

[0057] In the positioning process, the axial center of the drum 10 may be regarded as the axial center of the tire 500. The control device 90 acquires two positions acquired in the acquisition process that are spaced from the axial center of the drum 10 by the distance between the center of the tire 500 and the bead apex 58b. The two positions are opposite each other with respect to the center of the drum 10 in the axial direction of the drum 10. The acquired positions are designated as the first position P1 shown in FIG. 3. The first position P1 is the position where the bead 58 is disposed in the axial direction of the drum 10. The control device 90 further acquires a position that is, for example, half the height of the bead apex 58b and is inward from the first position P1 in the axial direction of the drum 10. This position is designated as the second position P2. The control device 90 then acquires a position that is 10 mm inward from the second position P2 in the axial direction of the drum 10. This position is designated as the pressing position CP. When the control device 90 calculates the pressing position CP, it controls the motor provided on the rail 70 shown in FIG. 5 to move the pressing roller 63 to a position aligned with the pressing position CP in the radial direction of the drum 10.

[0058] In this embodiment, next, a bead core 58a (see FIG. 4) and a bead apex 58b (see FIG. 4) are arranged at predetermined positions on both end portions of the carcass plies 52a, 52b. The bead core 58a and the bead apex 58b are arranged in the bead holding portion 30 by a conveying device (not shown). As described above, the piston ring 31 shown in FIG. 3 is driven to move the lock segment 32 radially outward, thereby holding the bead core 58a and the bead apex 58b in the bead holding portion 30. In this way, the step of arranging the bead core 58a and the bead apex 58b at predetermined positions on both end portions of the carcass plies 52a, 52b may be performed after the pressing step described above. The above-mentioned pressing process may be performed after the bead core 58a and the bead apex 58b are placed at predetermined positions at both ends of the carcass plies 52a and 52b, but before the inner liner 51, both ends of the carcass plies 52a and 52b, and the bead apex 58b are folded back by the turn-up bladder 40.

[0059] Next, a process (hereinafter also referred to as "turn-up process") is performed to fold back both ends of the cylindrical part 50 wound around the drum 10. The inner liner 51 and the carcass plies 52a, 52b are formed into a toroidal shape by expanding the central portions in the width direction toward the outer diameter. As shown in FIG. 4, when the turn-up bladders 40 fold back both ends of the cylindrical part 50, the gap between the drums 10 is narrowed by the gap adjustment mechanism 20, and the turn-up bladders 40 are filled with gas. This causes the turn-up bladders 40 to expand outside the bead holding portions 30 in the axial direction of the cylindrical part 50. At this time, as shown in FIG. 8, both ends of the inner liner 51 and both ends of the carcass plies 52a, 52b are folded back to wrap around the bead apex 58b. As shown in FIG. 8, when both end portions of the cylindrical part 50 are folded back, the tip portion 58ba of the bead apex 58b is deformed so as to move toward the center portion of the cylindrical part 50.

[0060] FIG. 8 is a diagram illustrating the vicinity of the bead 58 after being turned up. Here, the bead apex 58b is bent at approximately the center in the up-down direction. The second position P2 acquired by the positioning process approximately coincides with the position of the tip end 58ba of the bead apex 58b shown in FIG. 8 in the axial direction of the drum 10 (see FIG. 3). The pressing position CP is located 10 mm inward from the second position P2 in the axial direction of the drum 10, and the width of the pressing roller 63 (see FIG. 5) is 20 mm. Therefore, the pressing roller 63 presses a 20 mm range inward from the position of the tip end 58ba of the bead apex 58b. As shown in FIG. 8, when both ends of the cylindrical part 50 are folded back, an elastic force SF is generated in the bent portion of the bead apex 58b in a direction that returns it to its original shape. The pressing position CP is located more inward in the axial direction of the drum 10 than the position where the elastic force SF is generated. The pressing range of the pressing roller 63 (see FIG. 5) is a range of 10 mm from the pressing position CP in both the left and right directions as viewed in the drawing, and this range is inside the tip end 58ba of the bead apex 58b in the axial direction of the drum 10. That is, in the pressing process, the pressing roller 63 presses a range of 20 mm inside the position in the axial direction of the drum 10 where the tip end 58ba of the bead apex 58b will be located when the bead apex 58b is turned back during the turn-up process.

[0061] According to the tire manufacturing method disclosed herein, in the pressing process described above, the pressing roller 63 is pressed against the joint portion 51a of the inner liner 51 at a predetermined pressing position CP that is inside the position where the tip of the bead apex 58b will be positioned when the bead apex 58b is turned up. Specifically, the pressing process presses a range 20 mm inside the position where the tip portion 58ba of the bead apex 58b will be positioned. As a result of this process, as shown in FIG. 7 , the carcass ply 52a deforms to fit the shape of the inner liner 51 at the predetermined pressing position CP that is inside the position where the tip portion 58ba of the bead apex 58b will be positioned when the bead apex 58b is turned up during the turn-up process, thereby crimping the inner liner 51 and the carcass plies 52a, 52b together. Therefore, even if a cavity CV occurs between the inner liner 51 and the carcass ply 52a at that position due to the joint portion 51a of the inner liner 51, the cavity CV disappears.

[0062] In the pressing process, the drum 10 may be rotated while being pressed against the pressing roller 63. The direction in which the drum 10 is rotated may be, for example, the opposite direction to the direction in which the inner liner 51 is wound.

[0063] When the bead apex 58b is turned up by the turn-up process, a region where the inner liner 51 and the carcass plies 52a, 52b are firmly pressed together is formed inside the position where the tip portion 58ba of the bead apex 58b is located. In particular, even if a void CV is generated between the inner liner 51 and the carcass ply 52a due to the joint portion 51a of the inner liner 51 as shown in Fig. 6, the void CV disappears by the pressing process as shown in Fig. 7.

[0064] According to the inventors' findings, the position at which the pressure roller 63 is pressed is important in the pressing process. If the position at which the pressure roller 63 is pressed is outside the tip 58ba of the bead apex 58b to be turned over, that is, a position where the bead apex 58b to be turned over can overlap, the elastic force SF of the turned over bead apex 58b can act, and the cavity CV between the inner liner 51 and the carcass ply 52a caused by the joint portion 51a of the inner liner 51 can reopen.

[0065] In the subsequent shaping process, air is filled inside the inner liner 51 between the beads 58. At this time, the joint portions 51a of the inner liner 51 are exposed on the inner circumferential surface of the inner liner 51. Furthermore, a void CV may exist between the inner liner 51 and the carcass ply 52a due to the joint portions 51a of the inner liner 51. The air filled during the shaping process may enter the void CV between the inner liner 51 and the carcass ply 52a through the joint portions 51a exposed on the inner surface of the inner liner 51. The void CV between the inner liner 51 and the carcass ply 52a due to the joint portions 51a may be continuous in the tire width direction. Therefore, as shown by arrow B in FIG. 1 , air that has entered the void CV between the inner liner 51 and the carcass ply 52a through the joint portions 51a exposed on the inner surface of the inner liner 51 may permeate the inside of the low cover. Air permeating the inside of the low cover may cause problems, such as air accumulation and swelling.

[0066] In contrast, in this embodiment, before the bead apex 58b is turned up during the turn-up process, the pressing roller 63 is pressed against the pressing position CP, which is set inside the position where the tip end 58ba of the bead apex 58b to be turned up during the turn-up process will be located. This results in a strong pressure-bonded state between the inner liner 51 and the carcass plies 52a, 52b at this portion. This portion does not overlap with the turned-up bead apex 58b, and the elastic force SF of the turned-up bead apex 58b is less likely to act on this portion. Therefore, the pressure-bonded state between the inner liner 51 and the carcass plies 52a, 52b is maintained against the elastic force SF of the turned-up bead apex 58b during the turn-up process. Furthermore, this portion can eliminate a void CV between the inner liner 51 and the carcass ply 52a due to the joint portion 51a of the inner liner 51. Therefore, even if air enters through the joint portion 51a when the low cover is inflated in the shaping process, the air intrusion is blocked at the pressing position CP where the low cover is pressed in the pressing process, as shown by arrow A. This prevents the air filled in during the shaping process from penetrating inside the low cover. This prevents air from entering inside the low cover through the cavity CV between the inner liner 51 and the carcass ply 52a caused by the joint portion 51a of the inner liner 51. This prevents defects caused by air penetration and improves the yield rate in the production of the tire 500.

[0067] 3 and 5, the raw cover molding apparatus 1 includes a cylindrical drum 10, turn-up bladders 40 provided on both axial sides of the drum 10, a roller device 60 facing the outer circumferential surface of the drum 10 and equipped with a pressing roller 63 configured to be movable in the axial direction, and a control device 90 (see FIG. 1). The control device 90 is configured to perform a process in which the pressing roller 63 is pressed against the joint portion 51a of the inner liner 51, of the inner liner 51 and carcass ply 52b, which are layered on the outer periphery of the drum 10, before the inner liner 51 having a joint portion wrapped around the outer periphery of the drum 10 and both ends of the carcass ply 52b layered on the inner liner 51 are folded back by the turn-up bladders 40 to wrap around the bead apex 58b (see FIG. 4). In the process of pressing the pressing roller 63, the position at which the pressing roller 63 is pressed against the inner liner 51 and carcass ply 52b stacked on the outer periphery of the drum 10 is preferably set to a predetermined position inside the position at which the tip of the bead apex 58b is located when both end portions of the inner liner 51 and the carcass ply 52b are folded back by the turn-up bladder 40.

[0068] According to the proposed raw cover molding device 1, when the turn-up bladder 40 turns back both ends of the inner liner 51 and the carcass ply 52b during the pressing process, the pressing roller 63 is pressed against a predetermined position inside the position where the leading edge of the bead apex 58b is located. This allows the inner liner 51 and the carcass ply 52b to be pressed together inside the leading edge 58ba of the bead apex 58b. Even if a void CV exists at that location due to the joint portion 51a of the inner liner 51, the void CV is closed. Therefore, even if air fills the inside of the inner liner 51 between the beads 58 during the subsequent shaping process, the air is prevented from penetrating at that position. This prevents air from entering the inside of the raw cover through the void CV between the inner liner 51 and the carcass ply 52a due to the joint portion 51a of the inner liner 51. This can suppress problems caused by the penetration of air, and improve the yield in manufacturing the tire 500.

[0069] Furthermore, with this raw cover molding device 1, the position where the pressure roller 63 is pressed during the above-described pressing process is controlled to a predetermined position. Therefore, when the turn-up bladder 40 turns back both end portions of the inner liner 51 and the carcass ply 52b, the pressure roller 63 is stably pressed against a predetermined position inside the position where the leading end of the bead apex 58b is located. This allows the above-described pressing process to be performed more reliably and stably. This more reliably prevents the above-described problems caused by air penetration, and significantly improves the yield rate in the manufacture of the tire 500.

[0070] In the above-described embodiment, the pressure roller 63 presses the area 20 mm inward from the tip 58ba of the bead apex 58b. According to the inventor's findings, pressing the area 20 mm inward from the tip 58ba of the bead apex 58b with the pressure roller 63 tends to suppress problems caused by air getting inside the row cover. Note that the range of pressure applied by the pressure roller 63 in this embodiment is a specific aspect that can fully achieve the effects of the present invention, and is not limited thereto unless otherwise specified.

[0071] In the above-described embodiment, the control device 90 acquires data on the size of the tire to be manufactured from the storage device 210 of the external server device 200. The control device 90 acquires the pressing position CP from the acquired tire size data and moves the cylinder 61 to a position aligned with the pressing position CP in the radial direction of the drum 10. As a result, in the above-described pressing process, the position to which the pressing roller 63 is pressed is determined according to the size of the tire to be manufactured. This allows the pressing roller 63 to reliably press the pressing position CP. Therefore, it is possible to more accurately manage the winding of the cylindrical part 50 around the drum 10. In this case, the control device 90 may be provided with a database in which the relationship between the size of the tire to be manufactured and the pressing position CP is recorded in advance, and the control device 90 may be configured to acquire the pressing position CP based on the size of the tire to be manufactured.

[0072] Although various explanations have been given above regarding the invention disclosed herein, the invention disclosed herein is not limited to the above-described embodiments and modifications unless otherwise specified. Furthermore, the respective configurations of the various embodiments and modifications mentioned above can be combined as appropriate as long as they do not interfere with each other.

[0073] In the above-described embodiment, the roller device 60 is moved by the control device 90, but this is not limiting. The roller device 60 may be configured to be moved manually. For example, after the pressing position CP is determined by the positioning process, an operator may move the roller device 60 to a position aligned with the pressing position CP in the radial direction of the drum 10.

[0074] In the embodiment described above, two pressing rollers 63 are arranged along the axial direction of the drum 10, but this is not limiting. For example, if the front end 5F and the rear end 5Rr of the inner liner 51 are formed so as to be inclined with respect to the axial direction of the drum 10, the joint portion 51a of the inner liner 51 extends in a direction inclined with respect to the axial direction of the drum 10 when viewed from above the drum 10. In this case as well, in the process of pressing the pressing roller 63, the position at which the pressing roller 63 is pressed against the inner liner 51 and the carcass ply 52b that are layered on the outer periphery of the drum 10 is preferably set to a predetermined position inside the position at which the tip of the bead apex 58b is located when both end portions of the inner liner 51 and the carcass ply 52b are folded back by the turn-up bladder 40.

[0075] In the above-described embodiment, the second position P2 is a position that is half the height of the bead apex 58b inward from the first position P1 in the axial direction of the drum 10. However, this is not limiting. The second position P2 may vary depending on the bending position of the bead apex 58b. For example, if the bead apex 58b bends from the base of the bead apex 58b, the second position P2 may be inward from the first position P1 by the height of the bead apex 58b. The bending position of the bead apex 58b varies depending on, for example, the rigidity of the bead apex 58b. It is preferable that the operator calculate in advance a theoretical value of the bending position of the bead apex 58b.

[0076] The present invention (1) relates to a raw cover molding device. The raw cover molding device according to the present invention (1) is A cylindrical drum and turn-up bladders provided on both sides of the drum in the axial direction; a pressure roller that faces the outer peripheral surface of the drum and is configured to be movable in the axial direction; Control device and Equipped with The control device Before an inner liner having a joint portion wound around the outer periphery of the drum and both end portions of a carcass ply superposed on the inner liner are folded back by the turn-up bladder so as to wrap around a bead apex, a process is performed in which the pressing roller is pressed against the joint portion of the inner liner of the inner liner and the carcass ply superposed on the outer periphery of the drum, In the process of pressing the pressure roller, the position at which the pressure roller is pressed against the inner liner and the carcass ply stacked on the outer periphery of the drum is set to a predetermined position inside the position at which the tip of the bead apex will be located when both end portions of the inner liner and the carcass ply are folded back by the turn-up bladder.

[0077] The present invention (2) is a raw cover molding device according to (1), In the process in which the pressure roller is pressed, the pressure roller presses the inner liner and the carcass ply, which are stacked on the outer periphery of the drum, in an area 20 mm inward from the position where the tip of the bead apex is located when both ends of the inner liner and the carcass ply are folded back by the turn-up bladder.

[0078] The present invention (3) is a raw cover molding device according to (1) or (2), The control device The method further includes a process of acquiring data on the size of a tire to be built, In the process of pressing the pressure roller, the position at which the pressure roller is pressed against the inner liner and the carcass ply superimposed on the outer periphery of the drum is configured to be determined based on the acquired tire size data.

[0079] The present invention (4) relates to a method for manufacturing a tire. The tire manufacturing method according to the present invention (4) includes: a step of winding an inner liner around the outer periphery of the drum and joining the ends of the inner liner; a step of overlapping a carcass ply onto the inner liner wound around the outer periphery of the drum; a step of arranging a bead core and a bead apex at predetermined positions on both end portions of the carcass ply; a pressing step of pressing a pressing roller against a joint portion of the inner liner at a predetermined position inside a position where a tip end of the bead apex will be disposed when the bead apex is folded back, after the carcass ply is overlapped on the inner liner and before the bead apex is folded back, and Includes.

[0080] The present invention (5) is a method for manufacturing a tire according to (4), In the pressing process, when both ends of the inner liner and the carcass ply, which are stacked on the outer periphery of the drum, are folded back, the pressing roller presses a predetermined range 20 mm inside the position where the tip of the bead apex is located.

[0081] The present invention (6) is a method for manufacturing a tire according to (4) or (5), In the pressing step, the position at which the pressing roller is pressed against the inner liner and the carcass ply that have been overlapped in the overlapping step is determined based on data on the tire size. [Explanation of symbols]

[0082] 1 Low cover molding device 5F front end 5Rr rear end 10 drums 11 Torso 13 Grip Plate 13a Support part 14 Support cylinder 15 Guide plate 16 Pressing member 20 Spacing adjustment mechanism 21 Screw shaft 22 screw holes 23 Motor 24 Bearings 30 Bead retainer 31 Piston ring 31a Slope 32 Lock Segments 32a Elastic ring 32b Slope 40 Turn-Up Bladder 50 Cylindrical parts 51 Inner liner 51a Joint 51F front end 51Rr rear end 52 Carcass 52a, 52b carcass ply 53 Cushion Rubber 54 Breaker 54b Bead Apex 55 Undertread rubber 56 Tread rubber 57 Sidewall rubber 58 Bead 58a bead core 58b Bead Apex 58ba tip 59 Chafer 60 Roller device 61 cylinders 61a Rod 62 Support member 63 Pressure roller 70 Rail 90 Control device 100 Low Cover Molding System 200 External server device 210 Storage device 500 tires 510 Tread CP pressing position cv cavity NW Network P1 1st position P2 2nd position SF Elastic force

Claims

1. A cylindrical drum, turn-up bladders provided on both axial sides of the drum; A pressure roller that faces the outer circumferential surface of the drum and is configured to be movable in the axial direction; Control device and Equipped with The control device includes: Before an inner liner having a joint portion wound around the outer periphery of the drum and both end portions of a carcass ply overlapped on the inner liner are folded back by the turn-up bladder so as to wrap a bead apex, a process is performed in which the pressing roller is pressed against the joint portion of the inner liner of the inner liner and the carcass ply overlapped on the outer periphery of the drum, In the process of pressing the pressing roller, a position where the pressing roller is pressed against the inner liner and the carcass ply overlapped on the outer periphery of the drum is set to a predetermined position inside a position where a tip of the bead apex is disposed when both end portions of the inner liner and the carcass ply are folded back by the turn-up bladder. Low cover molding device.

2. 2. The raw cover molding device of claim 1, wherein in the process of pressing the pressure roller, the pressure roller presses an area of ​​the inner liner and the carcass ply that are stacked on the outer periphery of the drum, the area being 20 mm inward from a position where the tip of the bead apex is located when both ends of the inner liner and the carcass ply are folded back by the turn-up bladder.

3. The control device includes: The method further includes a process for acquiring data on the size of a tire to be molded, In the process of pressing the pressing roller, a position at which the pressing roller is pressed against the inner liner and the carcass ply overlapped on the outer periphery of the drum is determined based on the acquired data on the tire size. The raw cover molding apparatus according to claim 1 .

4. a step of winding an inner liner around an outer periphery of the drum and joining ends of the inner liner; A step of overlapping a carcass ply onto the inner liner wound around the outer periphery of the drum; A step of disposing a bead core and a bead apex at predetermined positions on both ends of the carcass ply; a pressing step of pressing a pressing roller against a joint portion of the inner liner at a predetermined position on the inside of a position where a tip end of the bead apex is to be disposed when the bead apex is folded back, after the carcass ply is overlapped on the inner liner and before the bead apex is folded back, of both end portions of the inner liner and the carcass ply of the inner liner and the carcass ply overlapped in the overlapping step; A method for manufacturing a tire, comprising:

5. 5. The tire manufacturing method according to claim 4, wherein in the pressing step, the pressing roller presses a predetermined range that is 20 mm inward from a position where a tip of the bead apex is located when both ends of the inner liner and the carcass ply are folded back, of the inner liner and the carcass ply that are overlapped on the outer periphery of the drum.

6. 5. The tire manufacturing method according to claim 4, wherein in the pressing step, a position at which the pressing roller is pressed against the inner liner and the carcass ply overlapped in the overlapping step is determined based on data on the size of the tire.

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