Low cover molding apparatus, turn-up bladder, and method for manufacturing a turn-up bladder.

Abstract

To improve turn-up bladder life.SOLUTION: An outer rubber sheet portion 62a is a rubber sheet portion that constitutes the outer surface of the turn-up bladder 62. The inner rubber sheet portion 62b is a rubber sheet portion constituting the outer surface of the turn-up bladder 62 and is disposed opposite the outer rubber sheet portion 62a. Two-layer cord portions 62c and 62d are disposed between the outer rubber sheet portion 62a and the inner rubber sheet portion 62b. The cord portions 62c and 62d comprise rubber layers including cords 62c1 and 62d1, respectively. A buffer rubber sheet portion 62e is a rubber layer disposed between the cord portions 62c and 62d.SELECTED DRAWING: Figure 3

Description

Technical Field

[0001] The present disclosure relates to a tire carcass molding apparatus, a turn-up bladder, and a method for manufacturing a turn-up bladder.

Background Art

[0002] Japanese Unexamined Patent Publication No. 2017-81021 discloses a tire carcass molding apparatus provided with a turn-up bladder. In the tire carcass molding apparatus disclosed herein, the turn-up bladder is arranged so as to straddle a bead lock member called a bead lock ring. The turn-up bladder is pressed against the bead core of the tire carcass when the tire carcass is molded. Further, the turn-up bladder expands and is restrained by a pusher. As a result, a portion of the tire carcass protruding outside the bead core is folded back and pressed against and joined to the main body portion of the toroidal tire carcass.

Prior Art Literature

Patent Literature

[0003]

Patent Literature 1

Summary of the Invention

Problem to be Solved by the Invention

[0004] Incidentally, such a turn-up bladder is gradually damaged by the molding of tire carcasses and may break in some cases. For this reason, it requires periodic replacement. From this point of view, it is desired to improve the service life of the turn-up bladder.

Means for Solving the Problem

[0005] The low cover molding apparatus disclosed herein includes a pair of cylindrical bodies configured to move toward and away from each other along a central axis, beadlock members provided on the outer circumferential surfaces of the pair of cylindrical bodies so as to project outward in the radial direction, and turn-up bladders arranged on the outer circumferential surfaces of the pair of cylindrical bodies so as to straddle the outer circumferential surfaces of the beadlock members. The turn-up bladder includes an outer rubber sheet portion, an inner rubber sheet portion arranged opposite to the outer rubber sheet portion, at least two cord portions arranged between the outer rubber sheet portion and the inner rubber sheet portion, each consisting of a rubber layer including cords, and a buffer rubber sheet portion arranged between two of the at least two cord portions.

[0006] The turn-up bladder disclosed herein is a turn-up bladder made of a tubular rubber sheet, and comprises an outer rubber sheet portion, an inner rubber sheet portion disposed opposite to the outer rubber sheet portion, at least two cord portions disposed between the outer rubber sheet portion and the inner rubber sheet portion, each consisting of a rubber layer containing a cord, and a buffer rubber sheet portion disposed between two of the at least two cord portions.

[0007] The method for manufacturing a turn-up bladder disclosed herein includes the following steps. A process of preparing an outer rubber sheet material, an inner rubber sheet material, at least two layers of cord ply, and a cushioning rubber sheet material; A step of stacking an outer rubber sheet material, an inner rubber sheet material, at least two layers of cord ply, and a cushioning rubber sheet material such that the inner rubber sheet material is positioned opposite the outer rubber sheet material, at least two layers of cord ply are positioned between the outer rubber sheet material and the inner rubber sheet material, and a cushioning rubber sheet material is positioned between two of the at least two layers of cord ply; This process involves vulcanizing and molding the outer rubber sheet material, inner rubber sheet material, two layers of cord ply, and cushioning rubber sheet material that have been layered during the stacking process. [Effects of the Invention]

[0008] The low-cover molding apparatus disclosed herein may improve the lifespan of the turn-up bladder.

[0009] The turn-up bladder disclosed here is resistant to damage.

[0010] The method for manufacturing a turn-up bladder disclosed herein may provide a turn-up bladder that is less susceptible to damage. [Brief explanation of the drawing]

[0011] [Figure 1] Figure 1 is a schematic diagram of the low cover molding apparatus 10. [Figure 2] Figure 2 is a cross-sectional view showing an example of the structure of the drum 12 of the low cover molding apparatus 10. [Figure 3] Figure 3 is a schematic cross-sectional view showing the cross-sectional structure of the turn-up bladder 62. [Figure 4] Figure 4 is a schematic diagram showing the movement of the turn-up bladder 62 when the low cover is formed. [Modes for carrying out the invention]

[0012] Hereinafter, one embodiment of the disclosure described herein will be explained with reference to the drawings. However, this disclosure is not limited to the following embodiment. Each drawing is schematic and does not necessarily reflect the actual object. Furthermore, each drawing is for illustrative purposes only and does not limit the present invention unless otherwise specified. In addition, the same reference numeral is used for components and parts that perform the same function, and redundant explanations are omitted. In this specification, notations such as "X~Y" indicating a numerical range mean "X or more and Y or less" unless otherwise specified.

[0013] This document discloses a novel structure for a turn-up bladder that can improve the lifespan of the turn-up bladder, a method for manufacturing such a turn-up bladder, and a low-cover molding apparatus employing such a turn-up bladder.

[0014] Low cover molding apparatus 10 Figure 1 is a schematic diagram of the low cover molding apparatus 10. Figure 2 is a cross-sectional view showing an example of the structure of the drum 12 of the low cover molding apparatus 10. As shown in Figure 1, the low cover molding apparatus 10 comprises a central shaft 11, a pair of left and right drums 12 and 13, a pair of left and right pushers 14 and 15, and a motor 16.

[0015] <Center axis 11> As shown in Figure 2, the central axis 11 has a support cylinder 11a and a rotating shaft 11b. The support cylinder 11a is fixed in the low cover molding apparatus 10. A guide groove 11a1 and an opening 11a2 are formed on the outer circumferential surface of the support cylinder 11a. The guide groove 11a1 is a groove that guides the drums 12 and 13 along the axial direction. The opening 11a2 is an opening that guides the slider 22 and has a long rectangular shape along the axial direction.

[0016] The rotating shaft 11b is positioned along the central axis inside the support cylinder 11a and is supported so as to be rotatable about the central axis relative to the support cylinder 11a via bearings (not shown). Screw grooves 11b1 and 11b2 are cut on the outer surface of the rotating shaft 11b in opposite directions on the left and right. The screw grooves 11b1 and 11b2 are formed symmetrically with respect to the center line of the area where the pair of left and right drums 12 and 13 are mounted. A nut fitting 21 and a slider 22 are attached to the screw grooves 11b1 and 11b2 of the central shaft 11.

[0017] <Drums 12, 13> The drums 12 and 13, as shown in Figures 1 and 2, are members mounted on the central shaft 11 at intervals, and are a pair of cylindrical bodies configured to move toward and away from each other along the central shaft. In this embodiment, the drums 12 and 13 have insertion holes through which the central shaft 11 is inserted. The inner peripheral surfaces of the drums 12 and 13 are provided with sliders 12a and 13a that fit into guide grooves 11a1 formed on the outer peripheral surface of the support cylinder 11a of the central shaft 11. The drums 12 and 13 are each supported by a slider 22 mounted on the support cylinder 11a. Therefore, the drums 12 and 13 move axially along the support cylinder 11a in accordance with the rotation of the rotating shaft 11b of the central shaft 11. Thread grooves 11b1 and 11b2 are formed on the rotating shaft 11b in opposite directions on the left and right sides. When the rotating shaft 11b is rotated in a first direction, the left and right drums 12 and 13 approach each other along the axial direction, and when the rotating shaft 11b is rotated in a second direction, they move away from each other in the opposite direction.

[0018] As shown in Figure 2, the drums 12 and 13 are provided with a bead lock mechanism 40 and a turn-up mechanism 60. In this embodiment, a space 40a for providing the bead lock mechanism 40, air passages 31, 32 and 33 for operating the bead lock mechanism 40 and the turn-up mechanism 60, and mounting portions 63 and 64 for mounting a turn-up bladder 62 are respectively provided on the drums 12 and 13.

[0019] The space 40a for providing the bead lock mechanism 40 has an axially extending space, and a guide hole 41a1 opening along the radial direction is formed at one end thereof. The guide hole 41a1 opens between the guide hole 41a1 and the mounting portions 63 and 64 for mounting the turn-up bladder 62. The air passage 31 for operating the bead lock mechanism 40 communicates with the space 40a. A first air passage 32 for operating the turn-up mechanism 60 opens between the first air passage 32 and the mounting portions 63 and 64 for mounting the turn-up bladder 62. The first air passage 32 for operating the turn-up mechanism 60 communicates with the space between the drums 12 and 13.

[0020] <Bead Lock Mechanism 40> The bead lock mechanism 40 is a mechanism for fixing a ring-shaped bead core 204 attached to a tire case 202 constituting a lower cover 200. In this embodiment, the bead lock mechanism 40 includes a bead lock member 41 and a pusher member 42.

[0021] <Bead Lock Member 41> The bead lock member 41 is a member attached to drums 12 and 13 and respectively provided on the outer peripheral surfaces of the pair of drums 12 and 13 so as to protrude in the outer diameter direction. In this embodiment, the bead lock member 41 is composed of a plurality of segments arranged in the circumferential direction of the drums 12 and 13. Each segment of the bead lock member 41 is attached to a guide hole 41a1 of the drums 12 and 13, and guided so as to be movable inward and outward in the radial direction of the drums 12 and 13. Therefore, the bead lock member 41 can protrude radially with respect to the drums 12 and 13, or can be retracted into the drums 12 and 13. The inner diameter end of each segment of the bead lock member 41 has an inclined surface 41a that is inclined such that the diameter increases as the distance from the center of the opposing drums 12 and 13 increases. In this embodiment, a ring-shaped spring 43 is stretched across each segment of the bead lock member 41. The spring 43 is stretched across each segment in a slightly expanded state. Each segment is biased radially inward by the elastic reaction force of the spring 43. The upper end surface of the bead lock member 41 has a recess into which the bead core 204 can fit. Although not shown in the drawings, a band may preferably be attached to fit the recess.

[0022] <Pusher Member 42> The pusher member 42 is mounted in the axial space of the space 40a for providing the beadlock mechanism 40, and a piston ring 42a is mounted on its outer circumferential surface. One end of the pusher member 42 has a contact portion 42b that abuts against the inclined surface 41a of the beadlock member 41. In this embodiment, the contact portion 42b is composed of an inclined surface that is inclined at the same angle as the inclined surface 41a of the beadlock member 41. The airway 31 for operating the beadlock mechanism 40 is located at the rear end of the pusher member 42 (opposite the side facing the beadlock member 41) and leads to the space 40a.

[0023] In the beadlock mechanism 40, compressed air is supplied to the airway 31, which pushes out the pusher member 42 and pushes up the beadlock member 41. Multiple segments of the beadlock member 41 are provided in the circumferential direction of the drums 12 and 13. When the segments of the beadlock member 41 rise, the beadlock member 41 is pushed outward radially from the drums 12 and 13. On the other hand, when air is drawn in from the airway 31, the pusher member 42 moves away from the beadlock member 41, and the elastic reaction force of the spring 43 causes the beadlock member 41 to descend into the drums 12 and 13. Thus, in this embodiment, the beadlock mechanism 40 operates by manipulating the air pressure on the rear end side of the pusher member 42 through the airway 31. This operates the pusher member 42 and controls the rising and falling of each segment of the beadlock member 41. Although the example shown here illustrates the pusher member 42 being operated by air pressure, the pusher member 42 may also be operated by hydraulic pressure.

[0024] <Turn-up mechanism 60> The turn-up mechanism 60 is equipped with a turn-up bladder 62. The turn-up bladder 62 is a component made of a rubber sheet and is provided on the outer surfaces of a pair of drums 12 and 13, respectively, so as to straddle the outer surface of the beadlock member 41.

[0025] In this embodiment, the pair of drums 12 and 13 are provided with a first mounting portion 63 and a second mounting portion 64 as described above. The first mounting portion 63 is provided circumferentially and continuously inward along the central axis 11 from the beadlock member 41. The second mounting portion 64 is provided with the beadlock member 41 It is provided circumferentially and continuously outward along the central axis 11. One end of the turn-up bladder 62 is attached to the first mounting portion 63, and the other end of the turn-up bladder 62 is attached to the second mounting portion 64. As a result, the turn-up bladder 62 forms a closed space that is circumferentially continuous along the outer circumference of the drums 12 and 13. A part of the turn-up bladder 62 covers the outer surface of the beadlock member 41. In addition, the turn-up bladder 62 has an air passage 32 formed in the drums 12 and 13 between the first mounting portion 63 and the second mounting portion 64 as an air supply path. When air is supplied into the turn-up bladder 62 through the air passage 32, the turn-up bladder 62 expands, and when the air inside the turn-up bladder 62 is sucked out through the air passage 32, it deflates.

[0026] As shown in Figure 1, the turn-up bladder 62 consists of a cylindrical rubber sheet that covers the outer circumference of the drums 12 and 13. Figure 3 is a schematic cross-sectional view showing the cross-sectional structure of the turn-up bladder 62. As shown in Figure 3, the turn-up bladder 62 comprises an outer rubber sheet portion 62a, an inner rubber sheet portion 62b, two layers of cord portions 62c and 62d, and a cushioning rubber sheet portion 62e. The outer rubber sheet portion 62a is the rubber sheet portion that constitutes the outer surface of the turn-up bladder 62. The inner rubber sheet portion 62b is the rubber sheet portion that constitutes the outer surface of the turn-up bladder 62 and is arranged opposite to the outer rubber sheet portion 62a. The two layers of cord portions 62c and 62d are arranged between the outer rubber sheet portion 62a and the inner rubber sheet portion 62b. The cord portions 62c and 62d are composed of rubber layers containing cords 62c1 and 62d1, respectively. The cord portions 62c and 62d may also be called ply layers. The cushioning rubber sheet portion 62e is a rubber layer positioned between the cord portions 62c and 62d.

[0027] Figure 3 schematically shows the positional relationship between the outer rubber sheet portion 62a, the inner rubber sheet portion 62b, the two-layer cord portions 62c and 62d, and the cushioning rubber sheet portion 62e. In Figure 3, the actual thicknesses of the outer rubber sheet portion 62a, the inner rubber sheet portion 62b, the two-layer cord portions 62c and 62d, and the cushioning rubber sheet portion 62e are not reflected in the drawing. Also, the turn-up bladder 62 is vulcanized, and while the boundaries between the outer rubber sheet portion 62a, the inner rubber sheet portion 62b, the two-layer cord portions 62c and 62d, and the cushioning rubber sheet portion 62e roughly reflect the boundaries of the sheets before vulcanization, they can be strictly ambiguous. 3-1 in Figure 3 is a plan view of the turn-up bladder 62. In 3-1 in Figure 3, the cords 62c1 and 62d1 of the cord portions 62c and 62d are schematically shown with dashed lines. As shown in 3-1 in Figure 3, the cords 62c1 and 62d1 intersect each other in a plan view in the thickness direction of the turn-up bladder 62. In the configuration shown in 3-1 in Figure 3, the cords 62c1 and 62d1 intersect at an angle of approximately 90 degrees. The intersecting of the cords 62c1 and 62d1 of the cord sections 62c and 62d in a plan view in the thickness direction of the turn-up bladder 62 improves the tensile strength of the turn-up bladder 62 in the direction in which the cords 62c1 and 62d1 extend.

[0028] Figure 3-2 is a schematic diagram showing the cross-sectional structure of the turn-up bladder 62. Figure 3-3 is a schematic diagram showing the cross-sectional structure of a predetermined portion P1 that straddles the outer circumferential surface of the beadlock member 41. In the predetermined portion P1 that straddles the outer circumferential surface of the beadlock member 41, as shown in Figure 3-3, there is a cushioning rubber sheet portion 62e between the cord portions 62c and 62d.

[0029] In the configuration shown in Figure 3, the cord portion 62c, which is located outside the cushioning rubber sheet portion 62e, does not extend to the portion P2 held by the first mounting portion 63 on the opposing sides of the pair of drums 12 and 13. Similarly, the cord portion 62d, which is located inside the cushioning rubber sheet portion 62e, does not extend to the portion P2 held by the first mounting portion 63. In this embodiment, the outer rubber sheet portion 62a, the cushioning rubber sheet portion 62e, and the inner rubber sheet portion 62b are superimposed on the portion P2 held by the first mounting portion 63. Although not shown in the illustration, the outer rubber sheet portion 62a may not be extended in the portion P2 held by the first mounting portion 63, and its outside may be covered by another rubber sheet portion.

[0030] Furthermore, in the configuration shown in Figure 3, either the cord portion 62c, which is located outside the cushioning rubber sheet portion 62e, or the cord portion 62d, which is located inside the cushioning rubber sheet portion 62e, does not extend to the portion P3 held by the second mounting portion 64 of the drums 12 and 13. In other words, at the portion P3 held by the second mounting portion 64 of the drums 12 and 13, a portion of the cord extends, ensuring the required strength for the turn-up bladder 62.

[0031] In this embodiment, the cushioning rubber sheet portion 62e is positioned in a predetermined portion P1 that straddles the outer circumferential surface of the beadlock member 41, between the outer rubber sheet portion 62a and the inner rubber sheet portion 62b. Thus, the cushioning rubber sheet portion 62e may be positioned only in the predetermined portion that straddles the outer circumferential surface of the beadlock member 41, between the outer rubber sheet portion 62a and the inner rubber sheet portion 62b. Furthermore, if there are no other issues, the cushioning rubber sheet portion 62e may also be provided in portions other than the predetermined portion P1 that straddles the outer circumferential surface of the beadlock member 41.

[0032] 《Manufacturing Method for Turn-Up Bladder 62》 The manufacturing method for such a turn-up bladder 62 includes the steps of preparing an outer rubber sheet material, an inner rubber sheet material, at least two layers of cord ply, and a cushioning rubber sheet material, stacking these materials together, and vulcanizing and molding them.

[0033] In the preparation process, an outer rubber sheet material, an inner rubber sheet material, a two-layer cord ply, and a cushioning rubber sheet material are prepared, corresponding to the outer rubber sheet portion 62a, the inner rubber sheet portion 62b, the two-layer cord portions 62c and 62d, and the cushioning rubber sheet portion 62e. The outer rubber sheet material, the inner rubber sheet material, and the cushioning rubber sheet material are rubber sheets that do not contain cords. A rubber sheet of a predetermined thickness is prepared by kneading and stretching the required rubber material into the outer rubber sheet portion 62a, the inner rubber sheet portion 62b, and the cushioning rubber sheet portion 62e so that they function as such. After that, they are preferably cut into predetermined shapes. The two-layer cord ply is preferably prepared as a so-called cord ply, in which multiple cord materials extending in predetermined directions are bonded to a rubber sheet.

[0034] Here, various materials can be used as the rubber material for the turn-up bladder. For example, suitable conventional rubber materials used for turn-up bladders can be used for the outer rubber sheet material, the inner rubber sheet material, and the cushioning rubber sheet material. As such rubber materials used for turn-up bladders, for example, rubber materials formulated for larger passenger car tires, so-called large SUV tires, rubber materials formulated for treads, and rubber materials formulated for sidewall rubber can be more preferably used. The amount of additives added should be set to an appropriate amount suitable for use as a turn-up bladder. The thickness of the outer rubber sheet material, the inner rubber sheet material, and the cushioning rubber sheet material before vulcanization molding should be, for example, about 1.0 to 2.0 mm each. The rubber material used for the cord ply can be the same rubber material used for the outer rubber sheet material, the inner rubber sheet material, and the cushioning rubber sheet material as appropriate. In addition, a nylon material such as nylon 66 can be used for the cord material used for the cord ply. The thickness of the cord material used in cord plying is, for example, about 0.55 mm, and for example, a cord material of about 0.40 mm to 0.7 mm is preferable.

[0035] In the process of layering the outer rubber sheet material, the inner rubber sheet material, the two layers of cord ply, and the cushioning rubber sheet material, it is preferable that they be layered in a predetermined order and at predetermined positions, as shown in Figure 3. Here, it is preferable that the inner rubber sheet material is positioned opposite the outer rubber sheet material, the two layers of cord ply are positioned between the outer rubber sheet material and the rubber sheet material, and the cushioning rubber sheet material is positioned between the two layers of cord ply. In this case, the order in which the outer rubber sheet material, the inner rubber sheet material, at least two layers of cord ply, and the cushioning rubber sheet material are layered is not limited unless otherwise specified.

[0036] In the vulcanization molding process, the outer rubber sheet material, the inner rubber sheet material, the two layers of cord ply, and the cushioning rubber sheet material, which were stacked in the stacking process, are vulcanized. At this time, it is preferable that the outer rubber sheet material, the inner rubber sheet material, the two layers of cord ply, and the cushioning rubber sheet material are pressed in the direction in which they are stacked (thickness direction) while being vulcanized.

[0037] In the configuration shown in Figure 3, during the stacking process, the cushioning rubber sheet material that will become the cushioning rubber sheet portion 62e is positioned in a predetermined area between the outer rubber sheet material and the inner rubber sheet material where the beadlock member 41 of the low cover molding device 10 makes contact. The shape of the cushioning rubber sheet material and its position between the outer rubber sheet material and the inner rubber sheet material should be determined to correspond to the predetermined area where the beadlock member 41 of the low cover molding device 10 makes contact. Furthermore, in a plan view in the thickness direction when the materials are stacked during the stacking process, the cords of the two layers of cord ply should intersect.

[0038] As shown in Figures 1 and 2, the turn-up bladder 62 is attached to the drums 12 and 13 of the low cover molding apparatus 10. The structure of the low cover molding apparatus 10 is as described above. In molding the low cover, as shown in Figure 1, the spacing between the drums 12 and 13 is adjusted to a predetermined spacing so that the position of the beadlock member 41 corresponds to the spacing of the bead core 204. As shown in Figure 1, separately prepared inner liners and carcass plies are wound around the drums 12 and 13 in sequence. This forms a cylindrical tire case 202 in which the inner liners and carcass plies are stacked in sequence. Subsequently, a ring-shaped bead core 204 is attached on top of the inner liners and carcass plies wound around the drums 12 and 13, aligned with the position of the beadlock member 41. The inner diameter of the bead core 204 is slightly larger than the beadlock member 41 when it is housed in the drums 12 and 13. A portion of the tire case 202 protrudes outside the bead core 204, which is secured by the beadlock member 41. When the low cover is formed, the beadlock member 41 is pushed up, as shown by the dashed line in Figure 2, to secure the bead core 204.

[0039] In this embodiment, a portion of the turn-up bladder 62 is mounted so as to straddle the beadlock member 41. As a result, the turn-up bladder 62 is pushed up in accordance with the rise of the beadlock member 41. The end A2 of the tire case 202 protrudes from the outside of the bead core 204. Below the protruding portion of the end A2 of the tire case 202 is the turn-up bladder 62, which covers the drums 12 and 13. At this time, the turn-up bladder 62 is in a deflated and folded state, covering the outer circumferential surface of the drums 12 and 13.

[0040] Figure 4 is a schematic diagram showing the movement of the turn-up bladder 62 when the low cover is formed. When the low cover is formed, the turn-up bladder 62 is inflated as shown in Figure 1. As a result, as shown in Figure 4, the end A2 of the tire case 202 that protrudes from the bead core 204 is lifted by the turn-up bladder 62. Compressed air is also supplied between the left and right drums 12 and 13 through the airway 33. In addition, the left and right drums 12 and 13 are brought closer together towards the center C0 of the left and right drums 12 and 13 by rotating the motor 16. As a result, the tire case 202 inflates in a toroidal shape between the bead cores 204 held by the bead lock members 41 of the left and right drums 12 and 13, as shown by the dashed line in Figure 1. Subsequently, as shown in Figure 4, the turn-up bladder 62 of the left and right drums 12 and 13 is pushed inward by the pushers 14 and 15. As a result, the end A2 of the tire case 202, which has been lifted by the turn-up bladder 62, encloses the bead core 204 and is pressed against the toroidal central part A1 of the tire case 202. This forms the toroidal shape of the low cover 200 and creates a bead at the end of the low cover 200. Subsequently, a separately prepared tread rubber 206 is attached to the toroidal low cover 200.

[0041] In the turn-up bladder 62 disclosed herein, as shown in Figure 3, two cord sections 62c and 62d, each composed of a rubber layer including cords 62c1 and 62d1, are positioned between the outer rubber sheet section 62a and the inner rubber sheet section 62b. Furthermore, a cushioning rubber sheet section 62e is positioned between the cord sections 62c and 62d. In this embodiment, the cushioning rubber sheet section 62e is located in the portion P1 where the turn-up bladder 62 straddles the outer peripheral surface of the beadlock member 41. The cushioning rubber sheet section 62e is interposed between the cords 62c1 and 62d of the cord sections 62c and 62d. Therefore, even when pushed up by the beadlock member 41 and strongly pressed against the overlapping portion of the tire case 202 and the bead core 204, the compressive force acting on the outer rubber sheet section 62a and the inner rubber sheet section 62b due to the cords 62c1 and 62d of the cord sections 62c and 62d is mitigated.

[0042] In this embodiment, in particular, the cords 62c1 and 62d1 of the cord sections 62c and 62d intersect in a plan view in the thickness direction of the turn-up bladder 62. Therefore, as shown in Figure 4, the end A2 of the tire case 202, which is lifted by the turn-up bladder 62, encloses the bead core 204 and is strongly pressed against the central part A1 of the toroidally bulging tire case 202. This allows for smooth and reliable molding of the low cover. On the other hand, the cords 62c1 and 62d1 of the cord sections 62c and 62d can be strongly pressed against the outer rubber sheet section 62a and the inner rubber sheet section 62b. The cords 62c1 and 62d1 are wires that reinforce the turn-up bladder 62 and have high rigidity. Also, because they are wires, they can apply strong compressive forces locally. Furthermore, the cords 62c1 and 62d1 intersect in a plan view in the thickness direction. Therefore, at the point where the cords 62c1 and 62d1 intersect, they press against each other in the thickness direction. However, there is a cushioning rubber sheet portion 62e between the cords 62c1 and 62d1, which acts as a cushioning material. As a result, the cords 62c1 and 62d1 are less likely to press strongly against the outer rubber sheet portion 62a and the inner rubber sheet portion 62b. Consequently, localized damage to the turn-up bladder 62 is suppressed even at the point where the cords 62c1 and 62d1 intersect. This extends the lifespan of the turn-up bladder 62.

[0043] Furthermore, in this embodiment, as shown in Figure 3, the turn-up bladder 62 further has a cord portion 62f including a cord on the inside of the inner rubber sheet portion 62b in the area where at least a part of the beadlock member 41 makes contact. In this embodiment, such a cord portion 62f is provided in the area P4 where the beadlock member 41 makes particularly strong contact with the inner surface of the turn-up bladder 62, for example, the area P4 where the edge of the upper end surface of the beadlock member 41 makes contact. This suppresses localized damage to the inside of the turn-up bladder 62. In this case, in the manufacturing method of the turn-up bladder 62, a cord ply corresponding to such a cord portion 62f is prepared, and the cord ply is further overlapped on the inside of the inner rubber sheet portion 62b in the predetermined area P4 where at least a part of the beadlock member 41 makes contact, and then vulcanized.

[0044] Here, as shown in Figure 3, two cord sections 62c and 62d, each consisting of a rubber layer containing cords, are arranged between the outer rubber sheet section 62a and the inner rubber sheet section 62b. More than two cord sections may be provided between the outer rubber sheet section 62a and the inner rubber sheet section 62b. In that case, the cushioning rubber sheet section is preferably arranged between at least two of the two cord sections. This suppresses localized damage to the turn-up bladder 62 and extends the lifespan of the turn-up bladder 62. Furthermore, if more than two cord sections are provided, a cushioning rubber sheet section may be provided between each cord section. This suppresses localized damage to the turn-up bladder 62 that may occur due to the cords in each cord section. Therefore, the lifespan of the turn-up bladder 62 is extended. In particular, localized damage to the turn-up bladder 62 that may occur due to the intersection of cords in the thickness direction is suppressed.

[0045] Although various aspects of the disclosure described herein have been explained, the disclosure is not limited to the embodiments and modifications described herein unless otherwise specified. Furthermore, the various embodiments and modifications described herein can be combined as appropriate, provided that they do not interfere with one another.

[0046] As described above, the present invention (1) relates to a low cover molding apparatus. The low cover molding apparatus in the present invention (1) is A pair of cylindrical bodies configured to move closer together and further apart along a central axis, The pair of cylindrical bodies are provided with beadlock members that protrude outward in the diametrical direction, Turn-up bladders are arranged on the outer circumferential surfaces of the pair of cylindrical bodies so as to straddle the outer circumferential surface of the beadlock member. It holds. The aforementioned turn-up bladder is, Outer rubber sheet part, An inner rubber sheet portion is arranged to face the outer rubber sheet portion, Displaced between the outer rubber sheet portion and the inner rubber sheet portion are at least two cord portions, each consisting of a rubber layer containing a cord, A cushioning rubber sheet portion is disposed between two of the two cord portions of the aforementioned at least two layers of cord portion. It holds.

[0047] The present invention (2) is a low cover molding apparatus as described in the present invention (1), The cushioning rubber sheet portion is positioned between the outer rubber sheet portion and the inner rubber sheet portion, and is located in a portion that spans at least the outer peripheral surface of the beadlock member.

[0048] The present invention (3) is a low cover molding apparatus described in the present invention (1) or (2), The pair of cylindrical bodies are A first mounting portion is provided circumferentially and continuously inward along the central axis from the beadlock member, to which one end of the turn-up bladder is attached, A second mounting portion is provided circumferentially and continuously to the outside along the central axis of the beadlock member, to which the other end of the turn-up bladder is attached, An air supply path provided between the first mounting portion and the second mounting portion and It holds.

[0049] The present invention (4) is a low cover molding apparatus described in any one of the present inventions (1) to (3), The two code sections intersect in a plan view in the thickness direction of the turn-up bladder.

[0050] The present invention (5) is a low cover molding apparatus described in any one of the present inventions (1) to (4), The turn-up bladder further has a cord portion, including the cord, inside the inner rubber sheet portion in the area where at least a part of the beadlock member makes contact.

[0051] The present invention (6) is a low cover molding apparatus described in any one of the present inventions (1) to (5), The cord portion, which is positioned outside the cushioning rubber sheet portion, does not extend to the portion held by the first mounting portion.

[0052] The present invention (7) is a low cover molding apparatus described in any one of the present inventions (1) to (6), The cord portion, which is positioned inside the cushioning rubber sheet portion, does not extend to the portion held by the first mounting portion.

[0053] The present invention (8) is a low cover molding apparatus described in any one of the present inventions (1) to (7), Either the cord portion located outside the cushioning rubber sheet portion or the cord portion located inside the cushioning rubber sheet portion does not extend to the portion held by the second mounting portion.

[0054] The present invention (9) relates to a turn-up bladder. The turn-up bladder in the present invention (9) is A turn-up bladder made of a tubular rubber sheet, Outer rubber sheet part, An inner rubber sheet portion is arranged to face the outer rubber sheet portion, Displaced between the outer rubber sheet portion and the inner rubber sheet portion are at least two cord portions, each consisting of a rubber layer containing a cord, A cushioning rubber sheet portion is disposed between two of the two cord portions of the aforementioned at least two layers of cord portion. It holds.

[0055] The present invention (10) is a turn-up bladder as described in the present invention (9), The cushioning rubber sheet portion is positioned in a predetermined portion between the outer rubber sheet portion and the inner rubber sheet portion, which spans at least the outer peripheral surface of the beadlock member.

[0056] The present invention (11) is a turn-up bladder as described in the present invention (9) or (10), The two code sections intersect in a plan view in the thickness direction of the turn-up bladder.

[0057] The present invention (12) is a turn-up bladder described in any one of the present inventions (9) to (11), In the area where at least a portion of the beadlock member makes contact, the inner rubber sheet portion further has a cord portion on the inside.

[0058] The present invention (13) relates to a method for manufacturing a turn-up bladder. The method for manufacturing a turn-up bladder in the present invention (13) is: The process involves preparing an outer rubber sheet material, an inner rubber sheet material, at least two layers of cord ply, and a cushioning rubber sheet material. A step of stacking the outer rubber sheet material, the inner rubber sheet material, the at least two layers of cord ply, and the cushioning rubber sheet material such that the inner rubber sheet material is positioned opposite the outer rubber sheet material, the at least two layers of cord ply are positioned between the outer rubber sheet material and the inner rubber sheet material, and the cushioning rubber sheet material is positioned between two of the at least two layers of cord ply, A step of vulcanizing the stacked outer rubber sheet material, the inner rubber sheet material, the two layers of cord ply, and the cushioning rubber sheet material in the stacking step described above. Includes.

[0059] The present invention (14) is a method for producing a turn-up bladder as described in the present invention (13), In the aforementioned stacking process, The cushioning rubber sheet material is positioned between the outer rubber sheet material and the inner rubber sheet material in a predetermined portion that is contacted by the beadlock member of the low cover molding device.

[0060] The present invention (15) is a method for producing a turn-up bladder as described in the present invention (13) or (14), In a plan view in the thickness direction when the two code plies are stacked during the stacking process, the code of the two code plies intersects.

[0061] The present invention (16) is a method for producing a turn-up bladder as described in any one of the present inventions (13) to (15), In the aforementioned stacking process, In a predetermined area where at least a portion of the beadlock member makes contact, a cord ply is further layered on the inside of the inner rubber sheet material. [Explanation of Symbols]

[0062] 10 Low cover molding apparatus 11 Center axis 11a Support tube 11a1 Guide groove 11a2 opening 11b Rotation axis 11b1, 11b2 screw grooves 12,13 Drums 12a, 13a Slider 14,15 Pusher 16 motors 21 Nut fittings 22 Sliders 31, 32, 33 Airways 40 Beadlock mechanism 40a space 41 Beadlock member 41a Slope 41a1 Guide hole 42 Pusher component 42a Piston ring 42b Contact part 43 Springs 60 Turn-up mechanism 62 Turn Up Bladder 62a Outer rubber sheet section 62b Inner rubber sheet section 62c, 62d Code Section 62c1,62d1 code 62d Code section 62e Cushioning rubber sheet section 62f Code Section 63 First mounting section 64 Second mounting section 200 Low Cover 202 Tire Case 204 Bead Core 206 Tread Rubber A1 Center of tire case 202 A2 End of tire case 202 C0 Center of drums 12 and 13 on the left and right P1 A predetermined portion that straddles the outer surface of the beadlock member 41 P2 Part held by the first mounting portion 63 of drums 12 and 13 P3 Part held by the second mounting portion 64 of drums 12 and 13 P4 The part where the edge of the upper end surface of the beadlock member 41 makes contact.

Claims

1. A pair of cylindrical bodies configured to move closer together and further apart along a central axis, The pair of cylindrical bodies are provided with beadlock members that protrude outward in the diametrical direction, Turn-up bladders are arranged on the outer circumferential surfaces of the pair of cylindrical bodies so as to straddle the outer circumferential surface of the beadlock member. It has, The aforementioned turn-up bladder is, Outer rubber sheet part, An inner rubber sheet portion is arranged to face the outer rubber sheet portion, Displaced between the outer rubber sheet portion and the inner rubber sheet portion are at least two cord portions, each consisting of a rubber layer containing a cord, A cushioning rubber sheet portion is disposed between two of the two cord portions of the aforementioned at least two layers of cord portion. Having, Low cover molding machine.

2. The low cover molding apparatus according to claim 1, wherein the cushioning rubber sheet portion is arranged in the portion between the outer rubber sheet portion and the inner rubber sheet portion that spans at least the outer peripheral surface of the beadlock member.

3. The low cover molding apparatus according to claim 1, wherein the two code sections intersect in a plan view in the thickness direction of the turn-up bladder.

4. The low cover molding apparatus according to claim 1, wherein the turn-up bladder further has a cord portion including the cord on the inside of the inner rubber sheet portion in a portion that contacts at least a part of the beadlock member.

5. The pair of cylindrical bodies are A first mounting portion is provided circumferentially and continuously inward along the central axis from the beadlock member, to which one end of the turn-up bladder is attached, A second mounting portion is provided circumferentially and continuously outward along the central axis from the beadlock member, to which the other end of the turn-up bladder is attached, An air supply path provided between the first mounting portion and the second mounting portion and Having, A low cover molding apparatus as described in claim 1.

6. The low cover molding apparatus according to claim 5, wherein the cord portion, which is positioned outside the cushioning rubber sheet portion, does not extend to the portion held by the first mounting portion.

7. The low cover molding apparatus according to claim 5, wherein the cord portion, which is positioned inside the cushioning rubber sheet portion, does not extend to the portion held by the first mounting portion.

8. A low cover molding apparatus according to any one of claims 5 to 7, wherein either the cord portion located outside the cushioning rubber sheet portion or the cord portion located inside the cushioning rubber sheet portion does not extend to the portion held by the second mounting portion.

9. A turn-up bladder made of a tubular rubber sheet, Outer rubber sheet part, An inner rubber sheet portion is arranged to face the outer rubber sheet portion, Displaced between the outer rubber sheet portion and the inner rubber sheet portion are at least two cord portions, each consisting of a rubber layer containing a cord, A cushioning rubber sheet portion is disposed between two of the two cord portions of the aforementioned at least two layers of cord portion. A turn-up bladder with a turn-up function.

10. The turn-up bladder according to claim 9, wherein the cushioning rubber sheet portion is arranged in a predetermined portion between the outer rubber sheet portion and the inner rubber sheet portion, at least spanning the outer peripheral surface of the beadlock member.

11. The turn-up bladder according to claim 9, wherein the two code sections intersect in a plan view in the thickness direction of the turn-up bladder.

12. The turn-up bladder according to claim 10, further having a cord portion on the inside of the inner rubber sheet portion in a portion where at least a part of the beadlock member makes contact.

13. The process involves preparing an outer rubber sheet material, an inner rubber sheet material, at least two layers of cord ply, and a cushioning rubber sheet material. A step of stacking the outer rubber sheet material, the inner rubber sheet material, the at least two layers of cord ply, and the cushioning rubber sheet material such that the inner rubber sheet material is positioned opposite the outer rubber sheet material, the at least two layers of cord ply are positioned between the outer rubber sheet material and the inner rubber sheet material, and the cushioning rubber sheet material is positioned between two of the at least two layers of cord ply, A step of vulcanizing the outer rubber sheet material, the inner rubber sheet material, the two layers of cord ply, and the cushioning rubber sheet material that have been stacked in the stacking step. including, A method for manufacturing turn-up bladder.

14. In the aforementioned stacking process, The cushioning rubber sheet material is positioned between the outer rubber sheet material and the inner rubber sheet material in a predetermined portion that is contacted by the beadlock member of the low cover molding device. A method for manufacturing a turn-up bladder as described in claim 13.

15. A method for manufacturing a turn-up bladder according to claim 13, wherein, in a plan view in the thickness direction when stacked in the stacking step, the cords of the two cord plies intersect.

16. In the aforementioned stacking process, A method for manufacturing a turn-up bladder according to claim 14, wherein a cord ply is further layered on the inside of the inner rubber sheet material in a predetermined area where at least a portion of the beadlock member makes contact.

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