JP4799305B2 - Turn-up bladder and method of forming the same - Google Patents

Description

  The present invention relates to a turn-up bladder attached to a band drum around which a carcass band of a tire is wound, and a method of forming the turn-up bladder that folds a carcass band around a bead core. The present invention relates to a device capable of improving shape retention performance.

  Conventionally, a method called a single molding method is known as one of radial tire molding methods, and this method includes a center drum 21 and respective axially arranged outer sides thereof as shown in FIG. A band drum 20 composed of a side drum 22 is used, and a member such as an inner liner rubber 11 is affixed on the center drum 21 and a side wall rubber 12 is affixed on the side drum 22, respectively. One or more radial carcass plies 13 are bonded to the outer side in the radial direction of the wall rubber 12 to form the carcass band 10, and then a pair of bead cores 14 are arranged outside the carcass band 10 to narrow the distance between the bead cores 14. 2, the carcass band 10 is connected to the bead core 14. The carcass band 10 is folded back so as to wrap around from the inside and outside in the axial direction to form a toroidal shape. Finally, a belt and a tread rubber (not shown) are attached to the outside of the toroidal carcass band 10 to attach a green tire. To form.

  As means for turning the carcass band 10 around the bead core, a turn-up bladder 90 attached to the band drum 20 is used. The turn-up bladder 90 expands by supplying a pressure gas therein, and the carcass band 10 10 side parts and a center part are comprised around the bead core 14, and it is comprised so that it can fold back. In the illustrated case, the bead core 14 is arranged outside the carcass band 10 in a state where the bead filler 15 is preset.

  Further, in this method, in order to suppress the deformation of the radial carcass ply 13 and wind it, it is preferable that the winding diameter of the radial carcass ply 13 at the center drum 21 and the winding diameter at the side drum 22 are substantially equal. Actually, since the sidewall rubber 12 is thicker than the inner liner rubber 11, the circumferential length of the center drum 21 and the side drum 22 is set to a length corresponding to the difference in thickness between these rubbers 11 and 12. Therefore, the center drum 21 is configured to have a larger diameter than the side drum 22. That is, the drum outer peripheral surface of the band drum 20 as a whole has end cylindrical surfaces 25 arranged at both ends in the axial direction, and a central cylinder arranged in the axial central portion having a diameter larger than that of the end cylindrical surface 25. It consists of a surface 26 and respective intermediate tapered surfaces 27 that connect these cylindrical surfaces 25 and 26 with conical surfaces. Here, the end cylindrical surface 25 is formed on the side drum 22, and the central cylindrical surface 26 and the intermediate tapered surface 27 are formed on the center drum.

  FIG. 3 is a cross-sectional view showing the turn-up bladder 90 in a state in which the turn-up bladder 90 is not attached to the band drum 20. The turn-up bladder 90 shows the carcass band 10 not only from the bead core 14 but also from the bead core 14. Since the axially inner portion also needs to be folded back, in the mounting posture, a central inner peripheral portion 91 extending in the axial direction region from the end cylindrical surface 25 to the tapered surface 27, and a central inner peripheral portion An end-side inner peripheral portion 92 that extends axially outward from 91 and an outer peripheral portion 93 that is disposed radially outward of these inner peripheral portions 91 and 92 are configured to form a bag.

  In FIG. 3, reference numerals 94 and 95 denote attachment portions for attaching the turn-up bladder 90 to the band drum 20. Further, the turn-up bladder 90 has a structure in which a large number of reinforcing cords 99 extending in the axial direction in an attached state are arranged in the rubber material at intervals in the circumferential direction.

  However, as the pressure gas is repeatedly supplied to and discharged from such a turn-up bladder 90, a portion located on the intermediate taper surface 27 is formed on the intermediate taper surface 27 as shown in FIG. A raised portion 99 is generated without fitting, and this causes a problem that the carcass band cannot be attached.

  The present invention has been made in view of the above-described problems, and the drum outer peripheral surface when a carcass band is attached is each end cylindrical surface disposed at both axial end portions, and the end portion. Mounted on the peripheral surface of the band drum consisting of a central cylindrical surface that is larger in diameter than the cylindrical surface and disposed in the axially central portion, and an intermediate tapered surface that connects these cylindrical surfaces to each other with a conical surface. An object of the present invention is to provide a turn-up bladder in which a portion located on the intermediate tapered surface fits the intermediate tapered surface and does not produce the raised portion, and a manufacturing method thereof.

<1> is arranged such that the outer peripheral surface of the drum when the carcass band is pasted is arranged at the axial end portion of each end cylindrical surface arranged at both axial end portions and at the axial center portion having a larger diameter than the end cylindrical surface. Mounted on the peripheral surface of the band drum formed by a central cylindrical surface and intermediate taper surfaces connecting these cylindrical surfaces to each other by conical surfaces, and from the end cylindrical surface to the intermediate taper surface A center-side inner peripheral portion extending in the axial direction region, an end-side inner peripheral portion extending outward in the axial direction from the central-side inner peripheral portion, and an outer periphery disposed on the radially outer side of these inner peripheral portions In a turn-up bladder for molding a tire that wraps the carcass band around the bead core arranged outside from the inside and outside in the axial direction by supplying a pressure gas to the space surrounded by these parts. ,
The center-side inner peripheral portion is a turn-up bladder characterized in that the center-side inner peripheral portion has a shape that widens toward the side farther from the side closer to the end portion-side inner peripheral portion.

<2> is a method for forming the turn-up bladder of <1>,
The mold outer peripheral surface is a shape in which the first cylindrical surface, the second cylindrical surface having a diameter larger than that of the first cylindrical surface, and the connecting tapered surface connecting these cylindrical surfaces with conical surfaces are arranged on the same axis. On the circumference of the bladder mold, the member for the inner peripheral portion on the center side having a width wider than the finish width is used, and at least a partial region in the width direction of the entire width region on the connection tapered surface and the second cylindrical surface. And an inner peripheral member arranging step of arranging the end side inner peripheral member so as to extend on the first cylindrical surface, and a width wider than the finishing width. An outer peripheral member disposing step of disposing the outer peripheral member on the radially outer side of the inner peripheral member; and the inner peripheral member and the outer peripheral member disposed on a bladder mold. A damp ribbon-like cloth is spirally wound on the outside in the radial direction. At least a second step of a steaming step of tightening the member by drying the cloth, a step of vulcanizing the member in the tightened state, and the center-side inner peripheral portion and the outer peripheral portion that have been vulcanized. A turn-up bladder forming method including an end portion removing step of removing an end portion extending on a cylindrical surface and finishing to a predetermined finish width.

  <3> is a method of forming a turn-up bladder in <1>, in which the width of the end portion to be removed of the central inner peripheral portion and the outer peripheral portion is 50 to 300 mm.

  According to <1>, the central inner peripheral portion has a shape that widens toward the side farther from the side closer to the end inner peripheral portion, so this shape is the surface shape of the intermediate tapered surface of the band drum. Accordingly, the contraction force does not act on the turn-up bladder, so that the problem that the turn-up bladder does not fit the intermediate taper surface and generates a raised portion can be prevented.

  According to <2>, the outer peripheral surface of the mold includes a first cylindrical surface, a second cylindrical surface having a diameter larger than that of the first cylindrical surface, and a connection tapered surface that connects these cylindrical surfaces with conical surfaces. On the circumference of the bladder mold having the shape arranged on the same axis, the member for the inner peripheral portion having a width wider than the finish width is formed between the full width region on the connection tapered surface and the second cylindrical surface. An inner peripheral member arranging step of arranging the member for the inner peripheral portion of the end portion so as to extend over at least a part of the width direction, and arranging the member for the inner peripheral portion of the end portion so as to extend on the first cylindrical surface The outer peripheral member having a width wider than the finishing width is disposed on the radially outer side of the inner peripheral member, and the inner peripheral member disposed on the bladder mold. And a damp ribbon-like cloth spirally outside the outer peripheral member in the radial direction. A winding step of fastening the member by drying the cloth after being wound on, a step of vulcanizing the member in a tightened state, and the vulcanized center inner peripheral portion and the outer peripheral portion, And an end portion removing step of removing at least the end portion extending on the second cylindrical surface to finish to a predetermined finish width, so that for the inner peripheral portion on the center side disposed on the connecting taper surface of the bladder mold Even after the turn-up bladder is taken out from the bladder mold, the member is formed so as to extend toward the end, and the central inner peripheral member is arranged so as to extend to a partial region in the width direction of the second cylindrical surface. The shape can be maintained, and the center side inner peripheral part can be finished to a desired divergent shape, and the center side inner peripheral part member does not extend to a partial region in the width direction of the second cylindrical surface. If Residual stress due to shrinkage of the organic fiber cord in the member occurs during vulcanization, and the finished turn-up bladder shrinks when taken out from the bladder mold, forming the inner peripheral part of the center side widening The problem of not being able to do arises.

  <3> According to <3>, since the width of the removed end portion of the central inner peripheral portion and the outer peripheral portion is 50 to 300 mm, the contraction after vulcanization of the central inner peripheral member is effective. If this width is less than 50 mm, the shrinkage prevention effect is not sufficient, whereas if this width exceeds 300 mm, the bladder mold becomes long and wasteful. In contrast to the increase, the anti-shrinkage effect does not increase.

  5A is a cross-sectional view showing a turn-up bladder according to the present invention, FIG. 5B is a cross-sectional view corresponding to the view taken along the line bb in FIG. 5A, and the turn-up bladder 30 is shown in FIG. As described above, the carcass band 10 attached to the band drum 20 shown in FIG. 1 and affixed to the periphery of the band drum 20 by supplying pressurized gas to the inside is disposed outside the band drum 20. Each of the pair of bead cores 14 functions so as to be folded back from both inside and outside in the axial direction, and extends in an axial region from the end cylindrical surface 25 to the tapered surface 27 in the mounting posture. A central inner peripheral portion 31, an end side inner peripheral portion 32 extending axially outward from the central side inner peripheral portion 31, and an outer peripheral portion disposed on the radially outer side of these inner peripheral portions 31, 32. It is configured to form a bag with 33 That. And the attachment part 34 which concerns on the attachment to the band drum 20 is provided in the axial direction outer side end of the center side inner peripheral part 31, and it is similarly provided in the axial direction center side end of the end part side inner peripheral part 32. Is provided with an attachment portion 35 for attachment to the band drum 20.

  Further, the turn-up bladder 30 has a structure in which a large number of organic fiber cords 38 extending in the axial direction in the attached state are arranged in the rubber material 37 at intervals in the circumferential direction.

Here, the feature of the turn-up bladder 30 is that the central inner peripheral portion 31 is farther from the side (diameter D ₁ ) closer to the end inner peripheral portion 32 (diameter D ₂ ) when the axis is vertical. The center-side inner peripheral portion 31 can be reasonably fitted to the intermediate taper surface 27 formed on the center drum 21, and thereby, Even in the repeated expansion / contraction diameter of the turn-up bladder 30, it is possible to prevent the swell from occurring here.

Here, it is preferable that the angle difference between the divergent angle θ ₂ of the central inner peripheral portion 31 and the divergent angle θ ₁ of the intermediate taper surface 27 formed on the center drum 21 is within 5 °. Most preferably, they are the same.

  A method for forming the turn-up bladder 30 will be described. The turn-up bladder 30 is formed by arranging and vulcanizing members constituting the turn-up bladder 30 around the bladder mold. FIG. 6 is a partial cross-sectional view showing the bladder mold. The bladder mold 40 is configured by arranging three molds on the same axis so as to be separated from each other. These dies have a first die 41 having a truncated cone at the tip, a second die 42 having a flat cylindrical shape, and a cylindrical shape having a narrower width than the second die. And a third mold 43 disposed between the second mold 42 and the second mold 42.

The bladder mold 40 has a diameter corresponding to the second mold 42 and the third mold 43 in the outer peripheral surface in the state where the first to third molds 41, 42, 43 are adjacent to each other. and phi ₁ and (a part portion there that the diameter .phi.3) first cylindrical surface 45, corresponding to the cylindrical portion of the first die 41, a large diameter phi ₂ than the diameter phi ₁ of the first cylindrical surface 45 And a connection taper surface 47 corresponding to the truncated cone portion of the first mold 41. The connection taper surface 47 includes the first cylinder surface 45 and the second cylinder surface. 46 is connected.

  6 to 10 are cross-sectional views for explaining a process of forming the turn-up bladder 30. First, as shown in FIG. 6, first to third molds 41 constituting a bladder mold 40, 42 and 43 are spaced apart from each other, and function as an attachment portion of the turn-up bladder 30 to the band drum 20 in a ring-shaped recess provided on the end surfaces of the first mold 41 and the second mold 42. Members 54 and 55 for the attachment portions 34 and 35 are arranged, respectively. As the members 54 and 55 for the attachment portions 34 and 35, an unvulcanized rubber material is usually used.

  Thereafter, the first to third molds 41, 42, 43 are brought close to each other so as to be adjacent to each other, and then the center which is a member for forming the central inner peripheral portion 31 in the turn-up bladder 30 of the product. The side inner peripheral member 51 is disposed so as to extend over the entire width of the connection taper surface 47 and at least a part of the first cylindrical surface 46 extending continuously thereto, and the product turn-up. An end-side inner peripheral member 52, which is a member for forming the end-side inner peripheral portion 32 in the bladder 30, is arranged to extend on the second cylindrical surface 45 (inner peripheral member arrangement). Process).

Next, as shown in FIG. 8, a member for forming the outer peripheral portion 33 of the product turn-up bladder 30 on the radially outer side of the center-side inner peripheral portion member 51 and the end-side inner peripheral portion member 52. Arranging a certain outer peripheral member 53 (outer peripheral member arranging step), prior to the outer peripheral member 53, on the outer side of the central inner peripheral member 51 and the end inner peripheral member 52, In a later vulcanization step, a release agent 61 is applied so that they do not adhere to the outer peripheral member 53. However, the α ₁ portion which becomes the bonding portion between the central inner peripheral member 51 and the outer peripheral member 53 and the α portion which becomes the bonding portion between the end inner peripheral member 52 and the outer peripheral member 53. It is important not to apply the release agent 61 to the _two portions.

  Although not shown in FIGS. 7 to 10, the inner peripheral members 51 and 52 and the outer peripheral member 53 are as shown in FIG. In the unvulcanized rubber material, a large number of organic fiber cords extending in the axial direction in the mounting posture of the turn-up bladder 30 are arranged in the circumferential direction.

  Thereafter, a ribbon-like cloth 62 sufficiently moistened with moisture is wound around the outer periphery member 53 in a spiral shape, and then left until the cloth 62 is dried (a steaming step). In the wrapping process, air bubbles are generated from the members in the vulcanization process by utilizing the fact that the cloth 62 is contracted by drying and pressure is applied to the inner peripheral members 51 and 52 and the outer peripheral member 53. These members 51, 52, 53 are strongly pressed against the bladder mold 40, and these members 51, 52, 53 move against the bladder mold 40 as the organic fibers shrink in the vulcanization process. To prevent it from shifting.

  Thereafter, the members 51, 52, 53 are accommodated in a vulcanizing can while being clamped around the bladder mold 40 with the cloth 62, and vulcanized by applying heat (vulcanizing process). Then, the bladder mold 40 is disassembled with the respective molds 41, 42, 43 constituting the bladder mold 40 being separated from each other, and the vulcanized members 51, 52, 53 are taken out from the bladder mold 40.

  At this time, the vulcanized members 51, 52, 53 are in a state close to the product turn-up bladder 30, and FIG. 10 is a cross-sectional view showing the turn-up bladder 30A in this state. The turn-up bladder 30 of the turn-up bladder 30A can be obtained by removing the end portion 36 integrally connected to the inner peripheral portion 31A on the center side and also integrally connected to the outer peripheral portion 33A. Therefore, as the last step, the anvil 63 was inserted inside the end of the turn-up bladder 30A, and the blade was inserted at the position of the arrow CU, and extended at least on the second cylindrical surface 46. The end portion 36 is removed, and the center side inner peripheral portion 31A and the outer peripheral portion 33A are finished to a predetermined finishing width (end portion removing step).

  As described above, in the method of forming the turn-up bladder according to the present invention, the center-side inner peripheral portion 31 and the outer peripheral portion 33 in the final product shape have a divergent shape. The nap bladder 30A is once vulcanized and formed, and after the vulcanization, it is characterized by a process of cutting and removing an extra cylindrical portion. The dimensions can be stabilized.

  Here, the width of the end portion 36 to be removed is preferably 50 to 300 mm.

  The present invention can be suitably used particularly for the production of large radial tires.

It is sectional drawing which shows the band drum to which the turnup bladder concerning this invention is attached. It is sectional drawing which shows the state which turned up the carcass band with the turnup bladder. It is sectional drawing which shows the conventional turnup bladder. It is sectional drawing for demonstrating the problem of the conventional turn-up bladder. It is sectional drawing which shows the turnup bladder of embodiment which concerns on this invention. It is sectional drawing which shows the bladder mold used for the formation method of the turnup bladder of embodiment which concerns on this invention. It is sectional drawing for demonstrating the formation method of a turnup bladder. FIG. 8 is a cross-sectional view showing a step that follows FIG. 7. FIG. 9 is a cross-sectional view showing a step that follows FIG. 8. FIG. 10 is a cross-sectional view showing a step that follows FIG. 9.

Explanation of symbols

DESCRIPTION OF SYMBOLS 10 Carcass band 11 Inner liner rubber 12 Side wall rubber 13 Radial carcass ply 14 Bead core 15 Bead filler 20 Band drum 21 Center drum 22 Side drum 25 End cylindrical surface 26 Central cylindrical surface 27 Intermediate taper surface 30 Turn-up bladder 30A Turn-up bladder 31, 31A Central side inner peripheral part 32 End side inner peripheral part 33, 33A Outer peripheral part 34, 35 Mounting part 36 End part 37 Rubber material 38 Organic fiber cord 40 Bladder mold 41 First mold 42 Second mold Mold 43 Third mold 45 First cylindrical surface 46 Second cylindrical surface 47 Connection taper surface 51 Central side inner peripheral member 52 End side inner peripheral member 53 Outer peripheral member 54, 55 For mounting portion Material 61 Release agent 62 Cloth 63 Anvil

Claims (3)

The drum outer peripheral surface when the carcass band is pasted is each end cylindrical surface disposed at both axial ends, and the central cylindrical surface having a diameter larger than the end cylindrical surface and disposed in the axial central portion These cylindrical surfaces are attached to the circumferential surface of the band drum formed by the respective intermediate tapered surfaces that are connected to each other by conical surfaces, and extend in the axial direction region from the end cylindrical surface to the intermediate tapered surface. The center side inner peripheral portion, the end side inner peripheral portion extending axially outward from the central side inner peripheral portion, and the outer peripheral portion disposed radially outward of these inner peripheral portions, In a turn-up bladder for molding a tire that wraps around the bead core disposed outside the carcass band from the inside and outside in the axial direction by supplying pressurized gas to the space surrounded by these,
The turn-up bladder is characterized in that the central inner peripheral portion has a shape that widens toward the side farther from the side closer to the end side inner peripheral portion. A method of forming a turn-up bladder according to claim 1,
The mold outer peripheral surface is a shape in which the first cylindrical surface, the second cylindrical surface having a diameter larger than that of the first cylindrical surface, and the connecting tapered surface connecting these cylindrical surfaces with conical surfaces are arranged on the same axis. On the circumference of the bladder mold, the member for the inner peripheral portion on the center side having a width wider than the finish width is used, and at least a partial region in the width direction of the entire width region on the connection tapered surface and the second cylindrical surface. And an inner peripheral member arranging step of arranging the end side inner peripheral member so as to extend on the first cylindrical surface, and a width wider than the finishing width. An outer peripheral member disposing step of disposing the outer peripheral member on the radially outer side of the inner peripheral member; and the inner peripheral member and the outer peripheral member disposed on a bladder mold. A damp ribbon-like cloth is spirally wound on the outside in the radial direction. At least a second step of a steaming step of tightening the member by drying the cloth, a step of vulcanizing the member in the tightened state, and the center-side inner peripheral portion and the outer peripheral portion that have been vulcanized. A method of forming a turn-up bladder comprising: an end portion removing step of removing an end portion extending on a cylindrical surface and finishing to a predetermined finish width.   The method of forming a turn-up bladder according to claim 2, wherein a width of an end portion to be removed of the central inner peripheral portion and the outer peripheral portion is 50 to 300 mm.

Images