JP5200124B2 - Pneumatic tire manufacturing method - Google Patents

Description

  The present invention relates to a method for manufacturing a pneumatic tire in which a bead core is formed by attaching a bead wire directly in a spiral shape on a core in a method of forming a raw tire cover using a core.

  In recent years, as shown in FIG. 12, a method for manufacturing a pneumatic tire using a core N having an outer peripheral surface that approximates the shape of the inner surface of the tire at the time of internal pressure filling (hereinafter referred to as “core method”) is described below. Patent Document 1 proposes this. In this core method, the inner liner 9, the inner and outer apex 8i, 8o, the carcass ply 6A, the bead core 5, the belt layer 7, the tread rubber 2G, the side wall rubber 3G, and the like are sequentially attached to the outer side of the core N. As a result, the raw cover 1a is formed, and the raw cover 1a is vulcanized together with the core N. This method has an advantage that the uniformity of the pneumatic tire 1 is improved because the stretch acting on the carcass and belt during vulcanization can be kept small.

  By the way, in the above-described core method, both ends of the carcass ply 6A cannot be folded. For this reason, on the bead core 5 of the raw cover 1a formed by the core method, the wire wound body 5a in which the bead wire 10 is spirally wound in the radial direction of the tire is arranged on both sides of the carcass ply 6A. The structure which sandwiches is adopted. For this reason, as shown in FIGS. 11A and 11B, the bead core 5 is previously ring-shaped on the bead molding surface B such as the outside of the apex 8i attached to the core N, for example. The wire wound body 5a wound and formed on the jig J was pressed and transferred.

  However, since the diameter of the wire wound body 5a varies depending on the tire size, in the above method, it is necessary to prepare a plurality of jigs for each tire size. Moreover, when the tire size to be manufactured was changed, the operation | work which replace | exchanges a jig | tool was also required. Therefore, the conventional core method has a problem that the manufacturing cost is high.

JP 2006-160236 A

  The present invention has been devised in view of the above problems, and in the core method, the manufacturing cost is reduced on the basis of forming a bead core by directly attaching a bead wire to a wire application surface in a spiral shape. The main object is to provide a pneumatic tire manufacturing method that can be reduced.

  The invention according to claim 1 of the present invention is a method of manufacturing a toroidal pneumatic tire having a pair of bead portions, and a core having an outer surface capable of forming a lumen surface of the pneumatic tire. To the outer surface of the inner liner, the outer surface of the bead portion of the inner liner pasted between the bead portions on both sides and / or the outer side of the inner liner, pasted between the bead portions of both sides in a toroid shape. A bead wire winding step in which a rubber-coated bead wire is spirally attached around a tire rotation axis to a wire application surface which is an outer surface of a bead portion of the carcass ply, and the bead wire winding step is performed by a pressing roller. A wire adhering step for adhering the winding start end of the bead wire to the wire adhering surface affixed to the core, and feeding the bead wire to the core side While rotating the core around the tire rotation axis, the bead wire is attached to the wire application surface along the tire circumferential direction at the pressing position by the pressing roller, and the pressing position is the tire of the core. And a wire vortex process in which the tire rotation axis of the core is inclined continuously or stepwise so as to move outward in the radial direction.

  The invention according to claim 2 further includes a step of keeping the pressing position at a substantially constant position by moving the core in a direction away from the pressing roller. It is.

  According to a third aspect of the invention, the bead wire spirally winds the bead wire from the inner side to the outer side in the radial direction of the tire, and the wire spiraling step is configured such that the bead wire is substantially constant from the winding start end. 3. An equal diameter winding step for winding with a diameter, and an increasing diameter winding step for increasing the winding diameter smoothly before the winding start end after the equal diameter winding step are alternately repeated. It is a manufacturing method of the pneumatic tire of description.

  The invention according to claim 4 is the method for producing a pneumatic tire according to any one of claims 1 to 3, wherein the bead wire is wound with adjacent bead wires in the tire radial direction substantially without any gap. .

  The invention according to claim 5 is the method for producing a pneumatic tire according to claim 3, wherein the bead wire wound in the diameter increasing winding step is substantially linear in a side view of the tire.

  In the method for manufacturing a pneumatic tire according to the present invention, the inner liner is bonded to the outer surface of the core having an outer surface capable of forming the inner cavity surface of the pneumatic tire so as to straddle between the bead portions on both sides. A rubber-coated bead wire is applied to the outer surface of the bead portion and / or to the wire application surface that is the outer surface of the bead portion of the carcass ply that is attached to the outer side of the inner liner and straddling between the bead portions on both sides. It includes a bead wire winding process in which a bead wire is attached around the tire rotation axis. Further, the bead wire winding step includes a wire fixing step of fixing a winding start end of the bead wire to the wire application surface attached to the core by a pressing roller, and the middle while feeding the bead wire to the core side. By rotating the child around the tire rotation axis, the bead wire is attached to the wire application surface along the tire circumferential direction at the pressing position by the pressing roller, and the pressing position is on the outer side in the tire radial direction of the core. It includes a wire vortex process for tilting the tire rotation axis of the core continuously or stepwise so as to move.

  In such a pneumatic tire manufacturing method, in the core method, by attaching the bead wire in a spiral shape directly to the wire application surface, it becomes unnecessary to separately prepare a jig for each tire size, That work is unnecessary. Therefore, the manufacturing cost can be greatly reduced. Further, in the present invention, as a result of changing the pressing position where the bead wire is pasted by moving the core, the path on the delivery side of the bead wire can be made constant, so that unnecessary bending and tension are not given to the bead wire. . Therefore, in the method for manufacturing a pneumatic tire of the present invention, the bead wire can be accurately attached to the wire application surface.

1 is a right half sectional view of a pneumatic tire manufactured by a method for manufacturing a pneumatic tire according to the present invention. It is a perspective view which shows the manufacturing apparatus used for the manufacturing method of the pneumatic tire of this invention. It is a side view of a sticking device. It is a perspective view of the core explaining the process of sticking an inner apex. It is a perspective view of the core explaining the wire adhering process of this embodiment. It is a perspective view of the core explaining the wire spiral process of this embodiment. It is a top view of the manufacturing apparatus explaining the wire spiral process of this embodiment. (A) is a side view explaining the inner core manufactured by the wire spiral process of this embodiment, (b) is a side view explaining the inner core manufactured by the wire spiral process of other embodiment. . It is a perspective view of the core explaining a carcass sticking process. It is a top view explaining the wire spiral process of other embodiment. (A), (b) is sectional drawing explaining the manufacturing method of the conventional bead core. It is a right half sectional view of the raw cover obtained by the core method.

Hereinafter, an embodiment of the present invention will be described with reference to the drawings.
FIG. 1 shows a cross-sectional view of a pneumatic tire (hereinafter sometimes simply referred to as “tire”) 1 obtained by the method for manufacturing a pneumatic tire of the present embodiment. The tire 1 has a toroidal shape having a pair of bead portions 4. The carcass 6 extends from the tread portion 2 through the sidewall portion 3 to the bead core 5 of the bead portion 4. For passenger cars comprising a belt layer 7 disposed inside the portion 2 and an inner liner 9 made of rubber having excellent air impermeability disposed inside the carcass 6 and on the tire cavity surface i. Things are shown.

  The tire 1 shown in FIG. 1 is shown in a normal state in which a rim is assembled on a normal rim (not shown), filled with a normal internal pressure, and is in an unloaded state.

  Here, the “regular rim” is a rim determined for each tire in the standard system including the standard on which the tire is based, for example, a standard rim for JATMA, “Design Rim” for TRA, For ETRTO, use “Measuring Rim”. In addition, “regular internal pressure” is the air pressure that each standard defines for each tire in the standard system including the standard on which the tire is based. The maximum air pressure for JATMA and the table “TIRE LOAD LIMITS AT for TRA” Maximum value described in “VARIOUS COLD INFLATION PRESSURES”, “INFLATION PRESSURE” for ETRTO, but 180 kPa for tires for passenger cars.

  The carcass 6 includes a carcass ply 6 </ b> A having a carcass cord extending from the tread portion 2 through the sidewall portion 3 to the bead core 5 of the bead portion 4. In the carcass ply 6A, carcass cords made of, for example, organic fibers are arranged at an angle of, for example, 75 to 90 ° with respect to the tire equator C. The carcass ply 6 </ b> A of the present embodiment straddles between the bead portions 4, 4 on both sides in the tire axial direction in a toroid shape, and the end portions 6 e on both sides are terminated in the bead core 5 without being folded back by the bead core 5. Yes.

  The belt layer 7 is composed of at least two belt plies 7A and 7B, in the present embodiment, in the tire radial direction, and in the outer two. Each of the belt plies 7A and 7B has a highly elastic belt cord such as a steel cord inclined at an angle of 15 to 40 ° with respect to the tire equator C. The belt plies 7A and 7B are overlapped so that the belt cords cross each other.

  In the present embodiment, the bead core 5 includes an inner core 11 disposed on the inner side of the carcass ply 6A in the tire axial direction and an outer core 12 disposed on the outer side of the carcass ply 6A in the tire axial direction. An end 6e of the carcass ply 6A is held between the inner and outer cores 11 and 12. The inner core 11 and the outer core 12 of the present embodiment are each formed by winding one bead wire 10, 10 in a row in the tire radial direction. However, the inner core 11 and the outer core 12 may be formed in a plurality of rows.

  In the present embodiment, a chafer rubber 4g made of hard rubber is disposed on the inner side in the tire radial direction of the bead core 5 in order to prevent wear due to contact with a rim (not shown).

  Further, as shown in FIG. 1, the bead portion 4 has an inner portion made of hard rubber and tapered toward the outer side in the tire radial direction on the inner side in the tire axial direction of the inner core 11 and on the outer side in the tire axial direction of the outer core 12. Outer apex 8i, 8o is provided.

  The pneumatic tire 1 configured as described above is manufactured by vulcanizing a raw cover 1a as shown in FIG.

  For example, as shown in FIG. 2, the raw cover 1 a rotates a core N having an outer surface that can form a lumen surface i (shown in FIG. 1) of the pneumatic tire 1 and the core N. It is manufactured using a manufacturing apparatus including a rotating device R to be rotated and a sticking device P for sticking the bead wire 10 to the outer surface N1 of the core N.

  The core N includes a tread molding surface Na that molds the lumen surface of the tread portion 2 of the tire 1, a pair of sidewall portion molding surfaces Nb that mold the lumen surface of the sidewall portion 3, and a bead portion 4. An outer surface N1 including a pair of bead molding surfaces Nc for molding the tire lumen surface. This outer surface N1 approximates to the inner surface of the tire in an internal pressure state of 5% of the normal internal pressure, for example. A pair of flange surfaces F projecting outward in the tire axial direction are provided at the bead side end of the outer surface N1. Such a core N is preferably made of a metal material, heat-resistant resin, or the like that can withstand heat and pressure during vulcanization. Furthermore, the core N of the present embodiment is supported in a state where the tire rotation axis is horizontal (Y-axis direction in the present embodiment).

  The rotating device R has, for example, a rectangular base 16 that can move on the floor surface in the horizontal direction (Y-axis direction in this embodiment), and an L-shape that is fixed to the base 16 so as to be rotatable about the vertical axis. Support frame 15.

  In the present embodiment, the base body 16 includes a slide mechanism 23a that engages with a guide rail 23b that is laid on the floor surface and extends in the Y-axis direction. And the base | substrate 16 can be moved to the Y-axis direction with the actuator etc. which are not shown in figure.

  The support frame 15 extends horizontally, and one end side of the support frame 15 is supported on a vertical first shaft 18 provided on the base 16 so as to be pivotable, and on the other end side of the horizontal portion 15b. And a vertical portion 15a extending vertically (Z-axis direction). A horizontal second shaft 17 is fixed to the upper end portion of the vertical portion 15a. A core N is detachably fixed to the second shaft 17.

  Accordingly, by rotating the second shaft 17 with an electric motor (not shown), the core N can rotate around the tire rotation axis CL. Further, the tire rotation axis CL of the core N can be tilted about the vertical axis by rotating the first shaft 18 with an electric motor (not shown) or the like. In the present embodiment, the center line Ca of the first shaft 18 intersects the tire rotation axis CL of the core N, and more specifically passes through the center O of the core N. Moreover, the electric motor etc. which rotationally drive each said axis | shafts 17 and 18 are controlled by a computer. Thereby, the rotation angle and inclination angle of the tire rotation axis CL of the core N are program-controlled by a predefined processing procedure.

  As shown in FIGS. 2 and 3, the sticking device P includes, for example, a transport roller 19 that transports the bead wire 10 wound around a reel (not shown) to the core N, and the transport roller 19. A pressing roller 20 for sticking the conveyed bead wire 10 to the outer surface N1 of the core N, and a cutting tool 21 for cutting the bead wire 10 are included.

  The bead wire 10 is previously coated with unvulcanized rubber on the outer peripheral surface of the wire by a topping device. Thereby, the bead wire 10 has adhesiveness on the surface, and can be firmly attached to the tire member on the core side.

  In this embodiment, the transport roller 19 is pivotally supported on a fixed plate 22 having a vertical mounting surface, for example, such that the rotation shaft is horizontal. A groove 19e extending in the circumferential direction is provided on the outer peripheral surface of each conveying roller 19, and the bead wire 10 is conveyed through the groove 19e without dropping off.

  The conveying roller 19 includes, for example, a driving roller 19a to which an electric motor Ma is connected, a guide roller 19b disposed on the upstream side of the driving roller 19a, and a plurality of small rollers disposed side by side on the outer periphery of the driving roller 19a. 19c.

  The driving roller 19a is composed of two juxtaposed in the wire feeding direction, and is connected to each other by a belt 25 so as to be rotatable.

  In the present embodiment, the guide roller 19b is composed of two juxtaposed in the wire feed direction, and the bead wire 10 is located above the rotation shaft of the upstream guide roller 19b and below the rotation shaft of the downstream guide roller 19b. Is wound through. Thus, by changing the winding direction of the bead wire 10 and passing it through the two guide rollers, the curl of the bead wire 10 and the residual stress that tend to occur when stored on the reel are removed.

  Further, the small roller 19c can effectively prevent the end portion of the bead wire 10 cut by the cutting tool 21 from jumping up from the driving roller 19a and coming off.

  The pressing roller 20 is supported by an actuator 26 such as a fluid cylinder. The actuator 26 includes a cylinder cylinder 26a and a rod 26b that can be moved in and out of the cylinder cylinder 26a by fluid pressure. The pressing roller 20 is pivotally supported at the tip of the rod 26b. In this embodiment, the bead wire 10 is conveyed and guided by the conveying roller 19 and the pressing roller 20 so as to move in an arbitrary vertical plane (shown in FIG. 7).

  The cutting tool 21 includes, for example, a push-cut cutter 21a and a lifting tool 21b such as a cylinder for lifting and lowering the cutter 21a. The cutter 21a is lowered by the pressing force of the lifting tool 21b, and the bead wire 10 passing between the drive rollers 19a and 19a is pushed.

  In the pneumatic tire manufacturing method of the present embodiment, the core N is attached to the second shaft 17 of the rotating device R as an initial state. Further, in the sticking device P, the pressing roller 20 is separated from the core N.

  Next, as shown in FIG. 4, on the outer surface N1 of the core N, the tire shaft of the base portion 4ga of the chafer rubber 4g, the inner liner 9, and the bead molding surface Nc of the base portion 4ga and the inner liner 9 is provided. The inner apex 8i is attached to the outside in the direction.

  The base portion 4ga of the chafer rubber 4g has, for example, an elongated cross section, and is wound around the bead molding surface Nc from the inner end in the tire radial direction to the outside in a small ring shape.

  Further, the inner liner 9 is formed in a three-dimensional curved surface by, for example, winding an unvulcanized and ribbon-shaped rubber strip g around the outer surface N1 of the core N in a spiral shape. For example, the rubber strip g preferably has a width W of about 5 to 35 mm and a thickness t of about 0.5 to 2.0 mm. The winding can be performed by rotating the second shaft 17 and moving a rubber strip g fed from a rubber supply device (not shown) at a predetermined pitch along the outer surface N1 of the core. In this embodiment, the entire inner surface N1 of the core N is covered with the inner liner 9 and the base portion 4ga.

  The inner apex 8i is disposed on the outer side in the tire axial direction between the base portion 4ga and the inner liner 9. Such an apex 8 i prevents the bead wire 10 of the inner core 11 from damaging the inner liner 9.

  Next, as shown in FIG. 5, the bead molding surface Nc of the core N is set in a predetermined position in the vicinity of the pressing roller 20 of the sticking device P. In the present embodiment, the tire rotation axis CL of the core N and the rotation axis of the conveying roller 19 of the sticking device P are set at a right angle. In the present embodiment, the rotation axis Cr (shown in FIG. 3) of the pressing roller 20 and the tire rotation axis CL of the core N are arranged at the same height. Thereby, the bead wire 10 can be sent out in the circumferential tangential direction on the bead molding surface Nc of the core N.

  Next, a step of forming the inner core 11 is performed. In this process, the outer surface of the bead portion 4 of the inner liner 9 (in this embodiment, the outer surface of the bead portion 4 of the apex 8i disposed on the outer side in the tire axial direction of the inner liner 9) is applied to the wire sticking surface S1. A bead wire winding step of attaching the bead wire 10 in a spiral shape around the tire rotation axis CL is included.

  The bead wire winding step includes a wire adhering step (shown in FIG. 5) for adhering the winding start end 10e of the bead wire 10 to the wire adhering surface S1, an adhering bead wire 10 to the wire adhering surface S1, and the core And a wire vortex process (shown in FIGS. 6 and 7) for inclining N tire rotation axes continuously or stepwise.

  In the wire adhering step, as shown in FIG. 5, the winding start end 10e of the bead wire 10 sent out by the conveying roller 19 is pressed to the core N side by the pressing roller 20, and a predetermined position on the wire affixing surface S1. (In this embodiment, the apex 8i is fixed to the inner end 8e in the tire radial direction). At this stage, since the inner apex 8i is also an unvulcanized rubber, the bead wire 10 is easily fixed to the inner apex 8i.

  When the wire fixing process is finished, a wire spiraling process is performed. As shown in FIG. 6, the wire vortex process rotates the core N around the tire rotation axis CL so that the bead wire 10 is pressed at the pressing position T (shown in FIG. 7) by the pressing roller 20. Affixed to the wire application surface S1 along the direction.

  Further, in this step, the tire rotation axis CL of the core N is inclined continuously or stepwise (stepwise in the present embodiment) so that the pressing position T moves outward in the tire radial direction of the core N. That is, in the present embodiment, by rotating the first shaft 18, the core N rotates clockwise around the Z axis where the tire rotation axis CL is vertical as shown in FIG. 7. As a result, the pressing position T moves to the outer side in the tire radial direction of the core N. In FIG. 7, the position of the core N ′ in the initial state of the bead wire winding process is represented by a virtual line.

  Further, in the present embodiment, the pressing position T is maintained at a substantially constant position by horizontally moving the core N away from the pressing roller 20 along with the rotation of the first shaft 18. Specifically, the pressing position T can be kept constant by moving the base 16 of the rotating device R backward on the guide rail 23b provided along the Y axis in a direction away from the sticking device P. it can. In such an embodiment, it is not necessary to move the sticking device P with the bead wire 10. Accordingly, it is sufficient that the bead wire 10 moves within a single vertical plane, and as a result of stabilization of the position, unnecessary bending, tension, torsion, etc. do not occur. Therefore, the bead wire 10 is affixed to the wire affixing surface S1 with high accuracy. Can be attached. Further, since the bead wire 10 can be pressed against the wire affixing surface S1 with a constant pressure, the bead wire 10 can be reliably affixed to the wire affixing surface S1 without damaging the rubber member such as the apex 8i.

  Further, as shown in FIGS. 7 and 8A, the inner core 11 is formed by winding bead wires 10a and 10b adjacent in the tire radial direction substantially without any gap. Thereby, the winding state of the bead core 5 is stabilized by the adhesive force of the unvulcanized rubber of the bead wires 10a and 10b adjacent in the tire radial direction, and the effect of preventing the carcass from coming off is exhibited. Incidentally, the “substantially no gap” means that the bead core extends in the tire circumferential direction and does not cause a gap between the bead wires 10a and 10b adjacent in the tire radial direction. An embodiment in which a gap exceeding the diameter d of the bead wire 10 does not occur in the tire radial direction is also included.

  In addition, the wire spiraling step includes winding the bead wire 10 with a substantially constant diameter from the winding start end 10e, and winding the bead wire 10 before the winding start end 10e after the constant diameter winding step. It is desirable to alternately repeat the increasing diameter winding step for smoothly increasing the diameter. In this embodiment, as shown in FIG. 8A, the inner core 11 includes an equal diameter region 11a formed by the equal diameter winding step, and an increased diameter region 11b formed by the increased diameter winding step. Consists of.

  The bead wire 10k constituting the increased diameter region 11b wound in such an increased diameter winding step is substantially linear in a tire side view. Moreover, the bead wire 10j which comprises the equal diameter area | region 11a wound by the equal diameter winding step makes | forms circular arc shape in tire side view. The inner core 11 formed in this way is excellent in uniformity. The “substantially linear” means that 80% or more of the tire circumferential direction length Lb of the increased diameter region is formed in a straight line, and of course, 80% or more of the tire circumferential direction length of the increased diameter region. The curvature radius may be formed to be 1.5 times or more the curvature radius of the equal-diameter region.

  In such a pneumatic tire manufacturing method, the bead core 5 can be formed by spirally attaching the bead wire 10 to the wire application surface S without using the jig J as in the prior art. Therefore, in the manufacturing method of the pneumatic tire of this invention, manufacturing cost can be reduced significantly.

  The tire rotation axis of the core N may be continuously inclined. For example, as shown in FIG. 8B, the inner core 11 manufactured by such a manufacturing method includes a bead wire 10 having a spiral-shaped increased diameter region formed only by an increased diameter winding step.

  Next, a carcass pasting step is performed in which the carcass ply 6A is pasted on the outer side of the inner core 11 in the tire axial direction. In this step, as shown in FIG. 9, for example, a plurality of strip-like ply pieces 6c that are longer in the radial direction of the tire than the length in the tire circumferential direction are connected to the outer side of the inner core 11 in the tire axial direction and the tire. By connecting in the circumferential direction, the three-dimensional carcass ply 6A is formed with high accuracy. The ply pieces 6c of this embodiment are attached in order from the vicinity of the inner end 11e of the inner core 11 in the tire radial direction. Further, the inner end portions 6i in the tire radial direction of the adjacent ply pieces 6c are arranged to face each other. In such a carcass sticking step, for example, the ply piece 6c is stuck by rotating the core N around the tire rotation axis CL.

  Next, after the ply piece 6c is attached to the entire circumference of the tire to form the carcass 6, a step of forming the outer core 12 is performed. In the present embodiment, the step of forming the outer core 12 is similar to the step of forming the inner core 11 on the wire bonding surface S2 that is the outer surface of the bead portion 4 of the carcass ply 6A, with the bead wire 10 around the tire rotation axis. It includes a bead wire winding step for pasting in a spiral shape. The bead wire winding step includes the wire fixing step and the wire spiral step.

  Then, after the step of forming the outer core 12, as shown in FIG. 12, the auxiliary apex 8o, the sub-portion 4gb that forms the bead outer surface and is connected to the base 4ga of the chafer rubber 4g, the belt layer 7, the side Wall rubber 3G, tread rubber 2G, and the like are attached to each other. In this way, the raw cover 1a is formed on the outer surface N1 of the core N.

  As another embodiment, as shown in FIG. 10, in the rotating device R, the base 16 is fixed, and the sticking device P is moved horizontally in a direction away from the core N, whereby the pressing position T is changed. It can be kept in a substantially constant position. Also in this embodiment, since the sticking device P moves along the vertical plane on which the bead wire 10 is transported, it is preferable in that bending does not act on the bead wire 10. The preferred embodiments of the present invention have been described in detail above, but the present invention is not limited to the illustrated embodiments, and can be implemented in various forms.

DESCRIPTION OF SYMBOLS 1 Pneumatic tire 4 Bead part 6A Carcass ply 9 Inner liner 10 Bead wire 10e Winding start end 20 of bead wire i Roller surface of tire N Core N1 Outer surface of core S Wire sticking surface T Press position

Claims (5)

A method for producing a toroidal pneumatic tire having a pair of beads,
The outer surface of the bead portion of the inner liner affixed between the bead portions on both sides in a toroidal shape to the outer surface of the core having an outer surface capable of forming the inner cavity surface of the pneumatic tire, and / or the A rubber-coated bead wire is spirally attached around the tire rotation axis on the wire application surface, which is the outer surface of the bead part of the carcass ply that is attached to the outside of the inner liner and straddling between the bead parts on both sides. Including a bead wire winding process for attaching,
The bead wire winding step is a wire adhering step of adhering a winding start end of a bead wire to the wire application surface attached to a core by a pressing roller;
By rotating the core around the tire rotation axis while feeding the bead wire to the core side, the bead wire is attached to the wire application surface along the tire circumferential direction at the pressing position by the pressing roller, and the pressing A method of manufacturing a pneumatic tire, comprising: a wire vortex process in which a tire rotation axis of the core is inclined continuously or stepwise so that the position moves outward in the tire radial direction of the core.   The method for manufacturing a pneumatic tire according to claim 1, further comprising a step of keeping the pressing position at a substantially constant position by moving the core in a direction away from the pressing roller. The bead wire spirally winds the bead wire from the inner side to the outer side in the tire radial direction,
The wire spiraling step is an equal diameter winding step of winding the bead wire with a substantially constant diameter from the winding start end;
The method for manufacturing a pneumatic tire according to claim 1 or 2, wherein after the equal diameter winding step, an increasing diameter winding step for smoothly increasing the winding diameter before the winding start end is alternately repeated. .   The method for manufacturing a pneumatic tire according to any one of claims 1 to 3, wherein the bead wire is formed by winding bead wires adjacent in the tire radial direction substantially without any gap.   The method for manufacturing a pneumatic tire according to claim 3, wherein the bead wire wound in the diameter increasing winding step is substantially linear in a side view of the tire.

Images