Bead manufacturing method and device

Abstract

To provide a bead manufacturing method and device capable of manufacturing beads whose surfaces are covered with a sheet material with good productivity, even for bead cores of various specifications. [Solution] When a circumferential portion of an annular bead core Bc inserted onto a drum body 8 is pressed toward a circumferential groove 8b formed on the outer peripheral surface of the drum body 8 by a pressure roller 13 to fit the bead core Bc into the circumferential groove 8b, a sheet material Bs is sandwiched between the circumferential portion of the bead core Bc and the circumferential groove 8b and pressed onto this circumferential portion, and the sheet material Bs is pulled out a predetermined length along the circumferential groove 8b as the drum body 8 and bead core Bc rotate, and both widthwise ends of the sheet material Bs extending circumferentially on the outer peripheral surface of the drum body 8 are folded back by folding guides 14a, 14b and pressed onto the surface of the bead core Bc, so that the surface of the bead core Bc is covered with the sheet material Bs over the entire circumferential length.

Description

[Technical Field]

[0001] The present invention relates to a method and apparatus for manufacturing a bead, and more particularly to a method and apparatus for manufacturing a bead that can productively manufacture beads whose surfaces are covered with a sheet material, even for bead cores of various specifications. [Background technology]

[0002] Various methods for covering the surface of an annular bead core that constitutes a tire by applying a sheet material are known (see, for example, Patent Document 1). In the method proposed in Patent Document 1, a sheet material (tape) is applied to the inner peripheral surface of the bead core by a pressure roller, starting from the position where the sheet material is applied to the inner peripheral surface of the bead core using a pressure roller (FIG. 8(a)), and the sheet material is then applied successively to the surface of the rotating bead core. In this way, the surface of the bead core is covered with the sheet material.

[0003] Bead cores are formed from metal wires, and if their surfaces are coated with, for example, unvulcanized rubber, they become sticky. The method proposed in Patent Document 1 allows the beginning of a sheet material to be fixed to the bead core if the adhesive strength is strong, but fails to securely fix the material if the adhesive strength is weak. Furthermore, with bead cores made solely from metal wires, it is difficult to secure the beginning of the sheet material to the surface of the bead core. If the beginning of the sheet material cannot be securely fixed to the surface of the bead core, the surface of the bead core cannot be stably and reliably covered with the sheet material. Therefore, there is room for improvement in the productive production of beads whose surfaces are coated with sheet material, even for bead cores with various specifications. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] Japanese Patent Application Publication No. 8-47984 Summary of the Invention [Problem to be solved by the invention]

[0005] An object of the present invention is to provide a bead manufacturing method and apparatus that can efficiently manufacture beads whose surfaces are covered with a sheet material, even for bead cores of various specifications. [Means for solving the problem]

[0006] In order to achieve the above object, the present invention provides a method for manufacturing a bead, in which a sheet material is attached to the surface of an annular bead core to cover the surface with the sheet material, and a circumferential groove extending in the circumferential direction is formed on the outer peripheral surface of a drum body having a diameter smaller than the inner diameter of the bead core, the bead core is fitted onto the drum body, and a circumferential portion of the bead core is pressed toward the circumferential groove by a pressure roller to fit the bead core onto the circumferential groove, and the drum body is rotated around the drum axis to rotate the bead core, and the bead core is fitted onto the circumferential groove sequentially over the entire circumferential length. When a circumferential portion of the bead core is fitted into the circumferential groove by fitting the sheet material supplied to the outer peripheral surface between the circumferential portion and the circumferential groove, the sheet material is pressed against the circumferential portion, and the sheet material is drawn out by a predetermined length along the circumferential groove by the rotating drum body and the bead core. Both widthwise ends of the drawn sheet material extending in the circumferential direction on the outer peripheral surface are folded back toward the bead core fitted into the circumferential groove and pressed against the surface of the bead core, thereby covering the entire circumferential length of the surface of the bead core with the sheet material. and before the circumferential portion is fitted onto the circumferential groove, the sheet material is pressed into the circumferential groove. It is characterized by: Another bead manufacturing method of the present invention is a method of manufacturing a bead by attaching a sheet material to the surface of an annular bead core and covering the surface with the sheet material, the method comprising: forming a circumferential groove extending in the circumferential direction on the outer peripheral surface of a drum body having a diameter smaller than the inner diameter of the bead core; inserting the bead core onto the drum body; pressing a circumferential portion of the bead core toward the circumferential groove with a pressure roller to fit the circumferential portion into the circumferential groove; and rotating the drum body around the drum axis to rotate the bead core so that the bead core is fitted sequentially into the circumferential groove over its entire circumferential length. When the circumferential portion of the bead core is fitted into the circumferential groove, the sheet material supplied to the outer peripheral surface is sandwiched between the circumferential portion and the circumferential groove and pressed against the circumferential portion to rotate the bead core. The sheet material is pulled out a predetermined length along the circumferential groove by the rotating drum body and the bead core, and both widthwise ends of the pulled-out sheet material extending circumferentially on the outer peripheral surface are folded back toward the bead core fitted into the circumferential groove and pressed against the surface of the bead core, thereby covering the surface of the bead core over the entire circumferential length, and perforations are formed in the sheet material along the supply path that supplies the sheet material to the outer peripheral surface, and when the perforations reach a predetermined position on the outer peripheral surface, tension is applied to the sheet material at a position near the perforations and upstream of the perforations while the drum body is still rotating, and this tension is used to cut the sheet material to the predetermined length at the perforations.

[0007] The bead manufacturing apparatus of the present invention has a pressure roller that presses and attaches a sheet material to the surface of an annular bead core, and manufactures a bead whose surface is covered with the sheet material. The bead manufacturing apparatus includes: a drum body having a diameter smaller than the inner diameter of the bead core; a folding guide that folds back the sheet material; and a supply source that supplies the sheet material to the outer peripheral surface of the drum body. A pressing jig; a circumferential groove extending in a circumferential direction is formed on the outer peripheral surface, and a circumferential portion of the bead core inserted onto the drum body is pressed toward the circumferential groove by the pressure roller and fitted onto the circumferential groove, and the bead core rotates by rotating the drum body around the drum axis, and the bead core is fitted onto the circumferential groove sequentially over the entire circumferential length, And, before the circumferential portion is fitted onto the circumferential groove, the sheet material is pushed into the circumferential groove by the pushing jig, The sheet material supplied to the outer peripheral surface is sandwiched between the circumferential portion fitted into the circumferential groove and the circumferential groove and pressed against the circumferential portion, and the sheet material is pulled out a predetermined length along the circumferential groove by rotation of the drum body and the bead core, and both widthwise ends of the pulled-out sheet material extending circumferentially on the outer peripheral surface are folded back by the folding guide toward the bead core fitted into the circumferential groove and pressed against the surface of the bead core, so that the surface of the bead core is covered with the sheet material over the entire circumferential length.

[0008] According to the present invention, the sheet material supplied to the outer peripheral surface is sandwiched between the circumferential portion fitted into the circumferential groove and the circumferential groove, and is pressed against the circumferential portion. Therefore, regardless of the adhesive strength of the surface of the bead core, the starting end of the sheet material when covering the bead core can be stably and firmly fixed to the surface of the bead core. Therefore, by rotating the bead core by rotating the drum body around the drum axis and fitting the bead core into the circumferential groove sequentially over the entire circumferential length, it is advantageous for highly productive production of beads whose surfaces are covered with the sheet material. [Brief explanation of the drawings]

[0009] [Figure 1] 1 is an explanatory diagram illustrating an embodiment of a bead manufacturing device in a side view. FIG. [Figure 2] 2 is an explanatory diagram illustrating the bead manufacturing apparatus of FIG. 1 as seen from the front. FIG. [Figure 3] 3 is an explanatory view illustrating a state in which a bead is being manufactured by the bead manufacturing apparatus of FIG. 2.

[0023] FIG. [Figure 4] 4 is an explanatory diagram illustrating the vicinity of the presser roller in FIG. 3 as viewed from above. [Figure 5] 4 is an explanatory view illustrating the periphery of the outer peripheral surface of the drum body as viewed from the arrow A in FIG. 3. [Figure 6] 4 is an explanatory diagram illustrating the periphery of the supply guide of FIG. 3 in a cross-sectional view. FIG. [Figure 7] 4 is an explanatory diagram illustrating the periphery of the presser roller of FIG. 3 in cross section. FIG. [Figure 8] 4 is an explanatory diagram illustrating the periphery of the pressing jig of FIG. 3 in a cross-sectional view. FIG. [Figure 9] 4 is an explanatory diagram illustrating the periphery of the upper pressure roller in FIG. 3 in cross section. FIG. [Figure 10] 4 is an explanatory diagram illustrating the periphery of the upper folding guide of FIG. 3 in a cross-sectional view. [Figure 11] 4 is an explanatory diagram illustrating the periphery of the central pressure roller in FIG. 3 in cross section. FIG. [Figure 12] 4 is an explanatory diagram illustrating the periphery of the lower folding guide of FIG. 3 in a cross-sectional view. [Figure 13] 4 is an explanatory diagram illustrating the periphery of the lower pressure roller in FIG. 3 in cross section. FIG. DETAILED DESCRIPTION OF THE INVENTION

[0010] Hereinafter, the bead manufacturing method and apparatus of the present invention will be specifically described based on the embodiments shown in the drawings.

[0011] 1 to 5, a bead B is manufactured in which the surface of an annular bead core Bc is covered with a sheet material Bs. Since the bead B is a tire component, its specifications are determined according to the tire performance, tire size, etc.

[0012] The bead core Bc is made of a metal wire such as a steel wire, and various known specifications can be used. The sheet material Bs is made of, for example, a woven fiber fabric impregnated with an RFL liquid (resorcinol-formalin-latex liquid), and has some adhesiveness. Various known specifications can be used for the sheet material Bs. The width of the sheet material Bs is set to be slightly longer than the circumference of the surface of the cross section of the bead core Bc.

[0013] This manufacturing apparatus 1 includes a drum body 8 having a diameter smaller than the inner diameter of the annular bead core Bc, pressure rollers 13 (13a, 13b, 13c) that press and attach a sheet material Bs to the surface of the bead core Bc, folding guides 14 (14a, 14b) that fold back the sheet material Bs, a supply reel 2 that serves as a supply source that supplies the sheet material Bs to the outer peripheral surface of the cylindrical drum body 8, and a control unit 17. The operation of the various components of the manufacturing apparatus 1 is controlled by the control unit 17. A known computer is used for the control unit 17.

[0014] A circumferential groove 8b extending over the entire circumferential length is formed on the outer peripheral surface of the drum body 8, which rotates around the drum shaft 8a. The supply path for the sheet material Bs runs from the supply reel 2 to the drum body 8. A number of support rollers are arranged along this supply path, and the sheet material Bs is stretched across these support rollers. Arrows X and Y in the figure indicate the front-to-rear and width directions of the manufacturing apparatus 1, respectively. The X and Y directions are perpendicular to each other. Also, dashed-dotted line CL indicates the width center of the drum body 8, and dashed-dotted line Z indicates the axis of the drum shaft 8a of the drum body 8. The width direction of the drum body 8 is the X direction, and the drum shaft 8a extends in the X direction.

[0015] The sheet material Bs is wound around a support shaft 2a extending in the Y direction on the supply reel 2. Arranged downstream of the supply reel 2 in the supply direction of the sheet material Bs are, in this order, a drive roller 3, a festoon unit 4, a perforation providing unit 5, a length adjustment mechanism 6, and a direction changing roller 7. The portion of the supply path downstream of the direction changing roller 7 will be described later.

[0016] The direction of the supply path is changed by 90° in plan view by the direction changing roller 7. Therefore, the support shaft 2a (axial center) of the supply reel 2 and the drum shaft 8a (axial center) of the drum body 8 are perpendicular in plan view. If the support shaft 2a (axial center) of the supply reel 2 and the drum shaft 8a (axial center) of the drum body 8 were configured to be parallel, the space required to install the manufacturing apparatus 1 would be excessively large. Therefore, by using the direction changing roller 7 to change the direction of the supply path by 90° midway, the manufacturing apparatus 1 is made more compact.

[0017] Drive roller 3, which is driven to rotate by an electric motor or the like, rotates supply reel 2 about support shaft 2a, thereby unwinding sheet material Bs from supply reel 2. Sheet material Bs unwound from supply reel 2 in this way is supplied toward the outer circumferential surface of drum body 8 as drum body 8 rotates. Festoon unit 4 has support rollers arranged spaced apart above and below, and by hanging sheet material Bs over these support rollers, it ensures excess length of sheet material Bs and also functions to apply an appropriate, constant tension to the hung sheet material Bs.

[0018] The perforation unit 5 has a blade portion 5a and a receiving portion 5b, and the blade portion 5a moves toward and away from the receiving portion 5b. As the blade portion 5a moves toward the receiving portion 5b, perforations are formed across the width of the sheet material Bs passing between the blade portion 5a and the receiving portion 5b. The perforation unit 5 can be of various known specifications.

[0019] The length adjustment mechanism 6 has a support roller that moves up and down and adjusts the length of the sheet material Bs supplied to the drum body 8 to cover one bead core Bc. When the support roller 6 moves downward, the length of the sheet material Bs for one bead core Bc increases, and when the support roller 6 moves upward, the length of the sheet material Bs for one bead core Bc decreases. A predetermined length L of the sheet material Bs required to cover one bead core Bc is set in advance, and the length adjustment mechanism 6 is controlled according to this predetermined length L. This predetermined length L is set to be slightly longer than the entire circumferential length of the bead core Bc.

[0020] A supply guide 9, a pressure roller 11, and a pushing jig 12 are arranged in this order on the supply path downstream of the direction change roller 7. The supply guide 9, pressure roller 11, and pushing jig 12 are arranged above the drum body 8 and in close proximity to the outer circumferential surface of the drum body 8. A sheet pusher 10 is arranged above the supply guide 9. The pushing jig 12 and the sheet pusher 10 can be provided as desired.

[0021] As shown in Figure 4, the supply guide 9 is a plate-like body with protruding edges on both ends, and these edges are spaced apart in the width direction of the drum body 8. The spacing between the protruding edges on both ends of the supply guide 9 is set to be slightly larger than the width dimension of the sheet material Bs. The supply guide 9 guides the sheet material Bs along the circumferential groove 8b and supplies it to the outer circumferential surface of the drum body 8. In this embodiment, the circumferential groove 8b is formed in the center of the width direction on the outer circumferential surface of the drum body 8, so the supply guide 9, sheet presser 10, presser roller 11, and pushing jig 12 are positioned according to the positions of the circumferential groove 8b.

[0022] The sheet presser 10 is a plate-like body made of, for example, metal or hard resin, and moves toward and away from the supply guide 9. When the sheet presser 10 moves toward the supply guide 9, the sheet material Bs passing between the sheet presser 10 and the supply guide 9 is sandwiched and fixed between the sheet presser 10 and the supply guide 9 (the supply movement of the sheet material Bs is stopped).

[0023] The rotatable pressure roller 11 presses the sheet material Bs guided by the supply guide 9 against the outer peripheral surface of the drum body 8. The sheet material Bs extends across the circumferential groove 8b on the outer peripheral surface of the drum body 8. In this embodiment, two pressure rollers 11 supported on one shaft are arranged spaced apart in the drum width direction, and these pressure rollers 11 press the sheet material Bs against the outer peripheral surface of the drum body 8 at positions sandwiching the circumferential groove 8b. It is preferable that the pressure rollers 11 be designed to be able to press both widthwise ends of the sheet material Bs to prevent the sheet material Bs from lifting up. The number of pressure rollers 11 is not limited to two as in this embodiment, and it is also possible to design one pressure roller 11 to press the sheet material Bs across the circumferential groove 8b.

[0024] The pressing jig 12 presses the sheet material Bs into the circumferential groove 8b. More specifically, the pressing jig 12 guides the widthwise center portion of the sheet material Bs into the circumferential groove 8b and presses it therein. The pressing jig 12 may be made of metal or hard resin, and may be designed to press the sheet material Bs into the circumferential groove 8b. As illustrated in FIG. 4, the width of the sheet material Bs placed on the outer peripheral surface of the drum body 8 is reduced by the amount by which the widthwise center portion of the sheet material Bs is pressed into the circumferential groove 8b by the pressing jig 12.

[0025] Next, other components arranged on the outer periphery of the drum body 8 will be described.

[0026] Following the supply guide 9, sheet presser 10, presser roller 11, and pushing jig 12, pressure rollers 13 (13a, 13b, 13c) and turn-back guides 14 (14a, 14b) are arranged on the outer periphery of the drum body 8. More specifically, the pressure rollers 13a, 13b, 13c are arranged in this order at intervals in the circumferential direction toward the downstream side in the supply direction of the sheet material Bs. One turn-back guide 14a is arranged between the pressure rollers 13a and 13b, and the other turn-back guide 14b is arranged between the pressure rollers 13b and 13c.

[0027] A pair of guide rollers 16a, 16b are arranged opposite the pressure roller 13 and the folding guide 14 across the drum body 8. The rotatable guide rollers 16a, 16b are arranged at intervals in the width direction of the manufacturing apparatus 1, and the guide rollers 16a, 16b move integrally in the width direction of the manufacturing apparatus 1. The pair of guide rollers 16a, 16b are arranged so that the bead core Bc fitted onto the drum body 8 passes between them.

[0028] 2, the pressure roller 13 and the return guide 14 are fixed to a movable frame 15 that moves toward and away from the outer circumferential surface of the drum body 8. Therefore, by moving the movable frame 15 toward the outer circumferential surface of the drum body 8, the pressure roller 13 and the return guide 14 move toward the outer circumferential surface of the drum body 8.

[0029] 5, the pressure roller 13 is a rotatable roller and is disposed across the circumferential groove 8b. The outer peripheral surface of the pressure roller 13 faces the outer peripheral surface of the drum body 8. The pressure roller 13 presses the sheet material Bs onto the surface of the bead core Bc, as will be described later.

[0030] As shown in Fig. 2, the folding guide 14 has an arc-shaped plate that fits along the outer peripheral surface of the drum body 8. As shown in Fig. 5, one folding guide 14a is positioned offset to one widthwise side of the circumferential groove 8b, and the other folding guide 14b is positioned offset to the other widthwise side of the circumferential groove 8b. The folding guides 14a and 14b fold back both widthwise ends of the sheet material Bs toward the bead core Bc, as will be described later.

[0031] Next, an example of a procedure for manufacturing the bead B using this manufacturing apparatus 1 will be described.

[0032] First, as shown in Fig. 2, the bead core Bc is fitted onto the drum body 8 with the movable frame 15 separated from the outer peripheral surface of the drum body 8. Using a known transfer or the like that can grip and move the bead core Bc, the bead core Bc is inserted between a pair of guide rollers 16a, 16b and fitted onto the drum body 8. The bead core Bc is set so that the widthwise position of the drum body 8 of the bead core Bc coincides with the circumferential groove 8b.

[0033] Next, as shown in FIG. 3, the movable frame 15 is moved close to the outer peripheral surface of the drum body 8, and the pressure roller 13 presses the outer peripheral surface of the bead core Bc. As a result, a circumferential portion of the bead core Bc (the circumferential portion corresponding to the area from the upper pressure roller 13a to the lower pressure roller 13c) is pressed toward the circumferential groove 8b, and the bead core Bc is fitted into the circumferential groove 8b. The pair of guide rollers 16a, 16b are moved integrally toward the other guide roller 16b, and the one guide roller 16a presses the inner peripheral surface of the bead core Bc. By maintaining the pair of guide rollers 16a, 16b in this position, a force acts on the bead core Bc in the direction toward the other guide roller 16b (Y direction), and the bead core Bc is stably fitted into the drum body 8.

[0034] With the bead core Bc fitted onto the drum body 8 in this manner, when the drum body 8 is rotated around the drum shaft 8a, the bead core Bc also rotates together with the drum body 8. The circumferential portion of the bead core Bc that is fitted into the circumferential groove 8b comes out of the circumferential groove 8b when it passes the pressure roller 13c. Therefore, when the bead core Bc continues to rotate together with the drum body 8, the bead core Bc is fitted into the circumferential groove 8b sequentially over its entire circumferential length.

[0035] In the supply path, the starting end (longitudinal leading end) of the sheet material Bs is pulled out slightly downstream of the pushing jig 12 (for example, between the pushing jig 12 and the pressure roller 13a). Then, the starting end of the sheet material Bs is sandwiched between the outer circumferential surface of the drum body 8 and the pressure roller 11.

[0036] As illustrated in Figure 3, when the starting end of the sheet material Bs is clamped between the outer surface of the drum body 8 and the pressure roller 11 and the drum body 8 is rotated around the drum shaft 8a, the sheet material Bs, which has been pressed against the outer surface of the drum body 8 by the pressure roller 11, passes through the pressing jig 12 and is pulled out toward the pressure roller 13a.

[0037] The pressure roller 13 causes a circumferential portion of the bead core Bc to fit into the circumferential groove 8b, so that the starting end of the sheet material Bs drawn toward the pressure roller 13a is sandwiched between the bead core Bc, which is fitted into the circumferential groove 8b, and the circumferential groove 8b, and is pressed against the bead core Bc. Therefore, the drawn-out sheet material Bs is sandwiched between the circumferential portion of the bead core Bc, which is fitted into the circumferential groove 8b, and the circumferential groove 8b, and is pressed against the circumferential portion. In this state, the rotating drum body 8 and bead core Bc draw the sheet material Bs along the circumferential groove 8b at a speed substantially equal to the rotational speed of the drum body 8 (the peripheral speed of the outer peripheral surface) without slipping relative to the outer peripheral surface of the drum body 8. The rotation of the drum body 8 and the bead core Bc draws out a predetermined length L of the sheet material Bs along the circumferential groove 8b. The surface of the bead core Bc is covered with the sheet material Bs over the entire circumferential length thereof by the sheet material Bs of the predetermined length L that has been pulled out.

[0038] The process of covering the surface of the bead core Bc over the entire circumferential length with the sheet material Bs will be described in detail with reference to FIGS.

[0039] As illustrated in FIG. 6, a supply guide 9 supplies sheet material Bs to the outer peripheral surface of the drum body 8 while restricting deviation in the width direction of the drum body 8. Next, as illustrated in FIG. 7, the sheet material Bs that has passed through the supply guide 9 is pressed onto the outer peripheral surface of the drum body 8 by a pressure roller 11. Next, as illustrated in FIG. 8, the sheet material Bs that has been pressed onto the outer peripheral surface of the drum body 8 is pressed into the circumferential groove 8b by a pressing jig 12. The pressed sheet material Bs assumes a shape that follows the cross-sectional shape of the circumferential groove 8b. In this embodiment, the sheet material Bs is not in contact with the groove bottom of the circumferential groove 8b.

[0040] 9, at the position of the pressure roller 13a, the outer peripheral surface of the bead core Bc is pressed by the pressure roller 13a, and the bead core Bc is fitted into the circumferential groove 8b. Since the sheet material Bs is interposed between the bead core Bc and the circumferential groove 8b, the sheet material Bs is sandwiched between the bead core Bc and the circumferential groove 8b and is pressure-bonded to the inner peripheral surface of the bead core Bc. When the leading end of the sheet material Bs is sandwiched between the bead core Bc and the circumferential groove 8b, the pressure roller 11 is moved away from the outer peripheral surface of the drum body 8, thereby releasing the pressure of the sheet material Bs against the outer peripheral surface of the drum body 8 by the pressure roller 11.

[0041] The specifications (size and cross-sectional shape) of the circumferential groove 8b are set according to the specifications (size and cross-sectional shape) of the bead core Bc, but a single circumferential groove 8b can be used for multiple bead cores Bc. When the sheet material Bs is sandwiched between the bead core Bc and the circumferential groove 8b, it is preferable that about half of the cross section of the bead core Bc protrudes outward from the outer circumferential surface of the drum body 8. That is, in the cross section of the bead core Bc, for example, 30% to 70%, more preferably 40% to 60%, of the thickness of the bead core Bc protrudes from the outer circumferential surface of the drum body 8. If the thickness of the bead core Bc that protrudes from the outer circumferential surface of the drum body 8 is excessively large (if the bead core Bc is shallowly fitted in the circumferential groove 8b), it is somewhat disadvantageous to stably press the sheet material Bs against the inner circumferential surface of the bead core Bc. If the thickness of the bead core Bc protruding from the outer peripheral surface of the drum body 8 is too small (if the bead core Bc is deeply fitted into the circumferential groove 8b), it will be disadvantageous for the bead core Bc to be smoothly removed from the circumferential groove 8b.

[0042] 10, one widthwise end of the sheet material Bs extending in the circumferential direction on the outer peripheral surface of the drum body 8 is folded back toward the bead core Bc fitted into the circumferential groove 8b using one of the folding guides 14a, thereby pressing the folded back portion of the sheet material Bs against the surface of the bead core Bc.

[0043] Next, as illustrated in FIG. 11, the outer peripheral surface of the bead core Bc on which the sheet material Bs is folded is pressed by the pressure roller 13b. This ensures that the folded portion of the sheet material Bs is pressed against the outer peripheral surface of the bead core Bc. When the pressure roller 13b presses the outer peripheral surface of the bead core Bc, it is preferable that the sheet material Bs covering the inner peripheral surface of the bead core Bc abuts against the groove bottom of the circumferential groove 8b, as illustrated in FIG. 11. That is, the sheet material Bs is pressed between the inner peripheral surface of the bead core Bc and the groove bottom of the circumferential groove 8b, so that the sheet material Bs is more firmly pressed against the inner peripheral surface of the bead core Bc. Note that with the other pressure rollers 13a and 13c, it is not necessary to abut the sheet material Bs covering the inner peripheral surface of the bead core Bc against the groove bottom of the circumferential groove 8b.

[0044] 12, the other widthwise end of the sheet material Bs extending circumferentially on the outer peripheral surface of the drum body 8 is folded back toward the bead core Bc fitted into the circumferential groove 8b using the other folding guide 14b. This causes the folded back portion of the sheet material Bs to be pressed against the surface of the bead core Bc. More specifically, the folded back portion of the sheet material Bs is overlapped and pressed against the sheet material Bs already pressed against the surface of the bead core Bc.

[0045] 13, the outer peripheral surface of the bead core Bc, in which both widthwise ends of the sheet material Bs are folded back, is pressed by a pressure roller 13c, thereby reliably pressing the overlapping portion of the sheet material Bs against the outer peripheral surface of the bead core Bc.

[0046] In this way, the bead cores Bc are fitted sequentially around the entire circumferential length into the circumferential grooves 8b, and the sheet material Bs is pressed onto the surfaces of the bead cores Bc, so that the surfaces of the bead cores Bc are covered with the sheet material Bs over the entire circumferential length. When the bead B manufactured in this manner is removed from the manufacturing apparatus 1, the pair of guide rollers 16a, 16b are moved together toward one of the guide rollers 16a. This causes the other guide roller 16b to press the outer peripheral surface of the bead B, making it easier to smoothly remove the bead B from the circumferential grooves 8b.

[0047] As described above, according to the embodiment of the manufacturing apparatus 1, the sheet material Bs supplied to the outer peripheral surface of the drum body 8 is sandwiched between the circumferential groove 8b and a circumferential portion of the bead core Bc fitted in the circumferential groove 8b, and is pressed against this circumferential portion. Therefore, regardless of the adhesive strength of the surface of the bead core Bc, the starting end of the sheet material Bs can be stably and firmly fixed to the surface of the bead core Bc when covering the bead core Bc. This prevents problems such as the sheet material Bs peeling off or shifting from the surface of the bead core Bc during the process of covering the surface of the bead core Bc. Therefore, sequentially fitting the bead core Bc into the circumferential groove 8b over the entire circumferential length is advantageous for efficiently manufacturing beads B whose surfaces are covered with the sheet material Bs over the entire circumferential length.

[0048] Therefore, this manufacturing apparatus 1 is particularly useful when the sheet material Bs cannot be firmly fixed to the surface of the bead core Bc due to the adhesiveness of the surface of the bead core Bc. In other words, this manufacturing apparatus 1 is useful for covering the surface of a bead core Bc with a sheet material Bs that has weak adhesiveness or is made only of metal wires.

[0049] In this embodiment, before a circumferential portion of the bead core Bc is fitted into the circumferential groove 8b, the sheet material Bs is pressed into the circumferential groove 8b using the pressing jig 12. Therefore, the widthwise center of the sheet material Bs can be precisely guided and pressed into the circumferential groove 8b. This allows the sheet material Bs to extend circumferentially with a desired width on the outer peripheral surface of the drum body 8 on both sides of the circumferential groove 8b. That is, it is possible to control the widthwise ends of the sheet material Bs, which are folded back toward the surface of the bead core Bc, to the desired width. As a result, the folding guides 14a and 14b allow the widthwise ends of the sheet material Bs to be folded back toward the surface of the bead core Bc without excess or deficiency. This improves the quality of the manufactured beads B.

[0050] In this embodiment, the perforation provider 5 forms perforations across the sheet material Bs midway along the supply path that supplies the sheet material Bs to the outer peripheral surface of the drum body 8. As the sheet material Bs is pulled out, for example, when the perforations reach a predetermined position in the range corresponding to the area between the pressure roller 11 and the pressure roller 13a, the sheet presser 10 is moved close to the supply guide 9, and the sheet material Bs is sandwiched between the supply guide 9 and the sheet presser 10, fixing the pulled-out sheet material Bs (stopping the supply movement of the sheet material Bs). This applies a large tension to the sheet material Bs, causing it to be cut at the perforations.

[0051] In this way, by fixing the sheet material Bs at a position upstream of and adjacent to the perforations when the perforations reach a predetermined position on the outer peripheral surface of the drum 8, the sheet material Bs can be cut to the predetermined length L by the perforations while the drum 8 is still rotating. This makes it possible to obtain the sheet material Bs of the required predetermined length L without stopping the rotation of the drum 8 that is producing the bead B, which is even more advantageous for producing the bead B with good productivity.

[0052] The leading edge of the sheet material Bs cut along the perforations becomes the starting edge of the sheet material Bs that will cover the next bead core Bc. When the sheet presser 10 is operated to cut the sheet material Bs along the perforations and simultaneously the perforation providing unit 5 provides perforations to the sheet material Bs, the length from the leading edge of the sheet material Bs cut along the perforations to the newly provided perforations becomes the length (predetermined length L) of the sheet material Bs to be used next. When the specification for cutting the sheet material Bs at the predetermined length L is not adopted as in this embodiment, the sheet material Bs is cut to the predetermined length L by known cutting means and supplied to the outer peripheral surface of the drum body 8 each time a bead core Bc is covered with the sheet material Bs. [Explanation of symbols]

[0053] 1 Bead manufacturing equipment 2 supply reels 2a spindle 3 Drive roller 4 Festoon Club 5 Perforation section 5a Blade part 5b Receiving part 6 Length adjustment mechanism 7 Direction change roller 8 drum body 8a Drum shaft 8b Circumferential groove 9 Supply Guide 10 Sheet holder 11 Presser roller 12 Pressing jig 13 (13a, 13b, 13c) Pressure roller 14(14a, 14b) Folding guide 15 moving frames 16a, 16b Guide rollers 17 Control Unit B bead Bc bead core Bs sheet material

Claims

1. A method for manufacturing a bead by attaching a sheet material to a surface of an annular bead core to cover the surface with the sheet material, a circumferential groove extending in a circumferential direction is formed on an outer peripheral surface of a drum body having a diameter smaller than an inner diameter of the bead core, The bead core is fitted onto the drum body, and a circumferential portion of the bead core is pressed toward the circumferential groove by a pressure roller to fit the bead core into the circumferential groove. In this state, the drum body is rotated around the drum axis to rotate the bead core, and the bead core is fitted into the circumferential groove sequentially over the entire circumferential length. When a circumferential portion of the bead core is fitted into the circumferential groove, the sheet material supplied to the outer peripheral surface is sandwiched between the circumferential portion and the circumferential groove and pressed against the circumferential portion, and the sheet material is pulled out a predetermined length along the circumferential groove using the rotating drum body and the bead core, and both widthwise ends of the pulled-out sheet material extending circumferentially on the outer peripheral surface are folded back toward the bead core fitted into the circumferential groove and pressed against the surface of the bead core, thereby covering the entire circumferential length of the surface of the bead core with the sheet material, and the sheet material is forced into the circumferential groove before the circumferential portion of the bead core is fitted into the circumferential groove.

2. A method for manufacturing a bead by attaching a sheet material to a surface of an annular bead core to cover the surface with the sheet material, a circumferential groove extending in a circumferential direction is formed on an outer peripheral surface of a drum body having a diameter smaller than an inner diameter of the bead core, The bead core is fitted onto the drum body, and a circumferential portion of the bead core is pressed toward the circumferential groove by a pressure roller to fit the bead core into the circumferential groove. In this state, the drum body is rotated around the drum axis to rotate the bead core, and the bead core is fitted into the circumferential groove sequentially over the entire circumferential length. a bead core having a circumferential groove and a peripheral surface that is adjacent to the circumferential groove, the bead core being fitted with a sheet material supplied to the peripheral surface; a bead core having a circumferential groove and a peripheral surface that is adjacent to the circumferential groove; a drum body and a bead core rotating together to form ...

3. The method for manufacturing a bead according to claim 2, wherein the sheet material is pressed into the circumferential groove before the circumferential portion is fitted onto the outside of the circumferential groove.

4. A bead manufacturing apparatus having a pressure roller that presses and attaches a sheet material to a surface of an annular bead core, the bead having the surface covered with the sheet material, The sheet material is folded back onto the outer peripheral surface of the drum body. A circumferential groove extending in a circumferential direction is formed on the outer circumferential surface, In a state where a circumferential portion of the bead core inserted on the drum body is pressed toward the circumferential groove by the pressure roller and fitted into the circumferential groove, the drum body is rotated around the drum axis to rotate the bead core, and the bead core is fitted into the circumferential groove sequentially over the entire circumferential length, and before the circumferential portion is fitted into the circumferential groove, the sheet material is pressed into the circumferential groove by the pressing jig, The sheet material supplied to the outer peripheral surface is sandwiched between the circumferential groove and the circumferential groove in a state where the circumferential portion is fitted onto the circumferential groove, and is pressed against the circumferential portion, and the sheet material is pulled out by a predetermined length along the circumferential groove by the rotation of the drum body and the bead core, The bead manufacturing device is configured such that both widthwise ends of the pulled-out sheet material extending circumferentially on the outer peripheral surface thereof are folded back by the folding guide toward the bead core fitted into the circumferential groove and pressed against the surface of the bead core, so that the surface of the bead core is covered with the sheet material over the entire circumferential length.

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