JP2008296553A - Manufacturing method of tire and tire molding drum used therefor - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a tire manufacturing method that prevents the air from entering between the bead core and the carcass habit-developing 93 and provide a tire molding drum used therefor. <P>SOLUTION: After the bead core 1 is locked by the bead lock mechanism 20, a plurality of the folding-back arms 32, which are arranged to the circumferential direction of the molding drum with a space in between and installed to be capable of swinging inward and outward to the drum radial direction with the base end 31 located outside away from the bead core 1 in the drum axial direction as the center, are moved in parallel to the center side in the drum axial direction from respective predetermined initial states until intermediate states and at the same time swung outwardly in the drum radial direction while the folding-back rollers 33 rotatably arranged on their head ends are brought into contact with the carcass inside member 2. Thereafter the folding-back arms 32 are kept in the intermediate states for a predetermined time to stick by pressing the habit-developing part 2F of the carcass ply 2 onto the outside in the tire axial direction of the bead core 1. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to a tire manufacturing method in which both ends of a carcass ply in the tire axial direction are stuck and locked to the outside in a radial direction of a bead core, and a tire molding drum used therefor, in particular, between a carcass ply and a bead core. It relates to a device that does not cause defects such as air entering.

  As schematically shown in a sectional view of the bead portion of the tire in FIG. 1, the bead cores 82 that are spanned between a pair of bead portions 81 and are arranged in each bead portion 81 are moved from the inner side to the outer side in the tire axial direction. A pneumatic tire including a carcass ply 83 made of one or more folded steel cords, and both ends 83E of the carcass ply 83 in the axial direction of the carcass ply are attached and locked to the radially outer sides of the corresponding bead cores 82. Is conventionally known (see, for example, Patent Document 1).

  As a method for manufacturing such a tire, when forming a raw tire, as shown in FIG. 2, the bead portion of the green tire being formed is shown in a cross-sectional view around the tire central axis, and the outer peripheral side in a direction facing each other. A carcass ply 93 having a brazing portion 93F that is brazed in a bent shape in the form of a flange at both ends in the tire axial direction, and a cylindrical shape wider than the carcass ply 93 that is attached to the inside in the tire radial direction After a carcass band 95 composed of a carcass inner member 94 is placed on a molding drum (not shown), the bead core 92 held by the bead holder 90 is attracted by, for example, a magnetic force, so that the axial direction of the molding drum The bead lock mechanism 9 is moved from the outer side toward the center side and is disposed at a predetermined position on the center side in the tire axial direction from the carcass ply flanged portion 93F. The bead cores 92 are supported by expanding their diameters, and a carcass ply 93 is attached to the inner side in the radial direction of these bead cores 92, and then the bead holder 90 is retracted toward the outer side in the tire radial direction as shown in FIG. Has been done.

  In the above method, when the bead core 92 is disposed at the predetermined position, as shown in FIG. 2, the bead holder 90 has the tip of the carcass ply brazed portion 93 </ b> F positioned on the outer side in the tire axial direction as compared with the natural state. By deforming in this way, as shown in FIG. 3, the carcass ply barb portion 93F is restored to its natural state when the bead holder 90 is retracted, and the tip of the carcass ply barb portion 93F is moved. It has been arranged at a predetermined position outside the bead core in the radial direction (see, for example, Patent Document 2).

JP-A-8-40026 JP 2007-1126 A

  However, in this conventional manufacturing method, the restoring force of the brazing part is often not sufficient, and in that case, defects such as air entering between the bead core 92 and the carcass brazing part 93F occur. Improvements were sought.

  The present invention has been made in view of such problems, and provides a tire manufacturing method in which air does not enter between the bead core and the carcass flanged portion 93F, and a tire molding drum used in the tire manufacturing method. With the goal.

<1> includes a carcass ply made of one or more steel cords that are bridged between a pair of bead portions and that are turned around from a bead core disposed in each bead portion from the inside to the outside in the tire axial direction. In the method for manufacturing a pneumatic tire, both ends of the carcass ply in the tire axial direction are stuck and locked to the radially outer sides of the corresponding bead cores.
Prior to vulcanization of the tire, when the green tire is molded, the brazed portions that are formed in a cylindrical shape and are bent in a hooked shape toward the outer periphery in the direction facing each other are attached to both ends in the tire axial direction. A first step of disposing on a molding drum a carcass band composed of a carcass ply having a portion and a cylindrical carcass inner member wider than the carcass ply attached to the inner side in the tire radial direction;
After the first step, each bead core held by the bead holder is disposed at a predetermined position on the center side in the tire axial direction from the brazed portion of the carcass ply, and the bead lock mechanism is expanded to support the bead core. A second step of attaching a carcass ply to the inner side in the radial direction of these bead cores;
After the second step, the bead holder is retracted and swings inward and outward in the drum radial direction centered on a base end portion located on the outer side in the drum axial direction with respect to the bead lock mechanism and spaced apart in the circumferential direction of the molding drum. A plurality of fold-back arms provided in a movable manner are arranged in a drum axial direction from a predetermined initial state to an intermediate state, respectively, while a fold-back roller rotatably disposed at the tip thereof is brought into contact with the carcass inner member. At the same time as being translated to the center side and simultaneously swinging outward in the drum radial direction, and then holding the folding arm in the intermediate state for a predetermined time, the brazed portion of the carcass ply is moved outward in the tire axial direction of the bead core. A third step of crimping;
After the second step, a fourth step of bulging the center part of the carcass band spanned between the bead cores in a toroidal manner while making the bead lock mechanisms on both sides approach each other;
After the third step and the fourth step, the both sides of the carcass ply inner member are moved by translating the folding arm further to the drum axial center side while keeping the folding roller in contact with the carcass inner member. This is a tire manufacturing method comprising a fifth step of folding the tire around the bead core.

  <2> is a method for manufacturing a tire according to <1>, wherein the fourth step is arranged after the third step.

<3> is a tire molding drum used in the method for manufacturing a tire according to <1> or <2>,
A main shaft that rotates on the axis of a molding drum and rotates the carcass band, a pair of bead lock mechanisms that are disposed around the main shaft on both outer sides in the axial direction and that support and fix a bead core from the inner side in the radial direction, and the bead lock mechanism A pair of folding mechanisms arranged around the main shaft on both outer sides in the axial direction and folding back both sides of the carcass band, and the bead lock mechanism and the folding mechanism are mounted one by one, and the main shaft is separated from each other. Comprising a pair of sliders configured to,
The folding mechanism includes a plurality of folding arms provided so as to be capable of swinging in and out of the radial direction of the forming drum with a base end portion positioned on the outer side in the axial direction as a center, and a folding roller disposed rotatably at a distal end portion thereof. Arm moving means for reciprocating the folding arm in the axial direction, a pair of stoppers for determining the outermost stop position in the axial direction in the axial reciprocation of the folding arm, and the stoppers in the axial direction Stopper displacement means for reciprocating displacement,
These stopper displacing means are tire molding drums configured to displace the stopper to positions where the folding arm can be positioned at respective stop positions corresponding to the initial state and the intermediate state.

<4> is configured such that in <3>, the slider has an outer peripheral surface and is slidable on the main shaft in the axial direction.
The stopper displacing means is composed of a stopper connecting cylinder that connects the driving cylinder and the stopper disposed on the center side in the axial direction from the stopper and slides on the outer peripheral surface of the slider.
The arm moving means includes a fixed piston fixed on the outer peripheral surface of the slider, a movable cylinder provided on the slider so as to be movable in the axial direction, and having a base end portion of the folding arm attached to be swingable. Consists of
The movable cylinder is composed of an outer cylindrical portion provided so that an inner peripheral surface slides on an outer peripheral surface of the fixed piston, and wall surface portions respectively attached to both ends of the outer cylindrical portion. The wall portion on the axial center side is configured to slide on the stopper connecting cylinder,
The stopper is a tire molding drum configured to be sandwiched between the fixed piston and an outer wall portion on the axial center side in the axially outermost position of the movable cylinder.

  According to <1>, after the second step, the bead holder is retracted, and arranged at an interval in the drum circumferential direction, with the base end portion positioned on the outer side in the drum axial direction from the bead lock mechanism as a center. A plurality of folding arms provided so as to be capable of swinging in and out of the drum radial direction are brought into contact with each other from a predetermined initial state while a folding roller disposed rotatably at the tip thereof is brought into contact with the carcass inner member. Until the state is translated to the center side in the drum axial direction and simultaneously swings outward in the drum radial direction, and then the folding arm is held in the intermediate state for a predetermined time, whereby the brazed portion of the carcass ply is moved to the bead core. A third step of crimping to the outer side in the tire axial direction of the tire, so that there are While preventing the air-filled can be crimped them reliably.

  According to <2>, since the fourth step is disposed after the third step, the carcass ply brazing portion and the bead core are crimped, and then the carcass band center portion is bulged in a toroidal shape. The portion can be further pulled in the pressure-bonding direction, and the entry of air between the brazed portion of the carcass ply and the outer portion in the tire axial direction of the bead core can be more reliably prevented.

  According to <3>, the folding mechanism includes a pair of stoppers for determining the outermost stop position in the axial direction in the axial reciprocation of the folding arm, and stopper displacement means for reciprocating the stopper in the axial direction. And the stopper displacing means is configured to displace the stopper to a position where the folding arm can be positioned at the respective stop positions corresponding to the initial state and the intermediate state. Can be held in an intermediate state.

  According to <4>, the stopper displacing means is configured by a stopper connecting cylinder that connects the driving cylinder and the stopper disposed on the center side in the axial direction from the stopper and slides on the outer peripheral surface of the slider. The arm moving means is a movable piston having a fixed piston fixed on the outer peripheral surface of the slider, a movable piston provided on the slider so as to be movable in the axial direction, and a base end portion of the folding arm attached to be swingable. The movable cylinder is composed of an outer cylindrical portion provided so that an inner peripheral surface slides with an outer peripheral surface of the fixed piston, and wall surface portions respectively attached to both ends of the outer cylindrical portion. Among these wall portions, the wall portion on the central side in the axial direction is configured to slide on the stopper connecting cylinder, and the stopper is the axially outermost portion of the movable cylinder. In the side position state, since it is configured to be disposed sandwiched between the outer wall portion and the fixed piston the axial center side, it can be realized in a simple structure of the tire building apparatus of <3>.

  Embodiments of the present invention will be described with reference to the drawings. 4 to 7 are cross-sectional views including a central axis showing the quadrant of the tire molding drum in different operating states. The tire molding drum 10 is arranged on the axis of the molding drum 10 and rotates the carcass band 4. Around the main shaft 11, a pair of bead lock mechanisms 20 arranged around the main shaft 11 on both outer sides in the axial direction and supporting and fixing the bead core 1 on the inner side in the radial direction, and around the main shaft 11 on both outer sides in the axial direction of the bead lock mechanism 20 A pair of folding mechanisms 30 arranged to fold back both side portions of the carcass band 4 and a pair of bead lock mechanisms 20 and folding mechanisms 30 mounted one by one and configured to be spaced apart from each other while sliding on the main shaft 11. And a slider 12.

  The slider 12 has a cylindrical shape, and on the radially inner surface, oppositely threaded screws are applied on the left and right sides of the male screw shaft 13 housed in the cylindrical main shaft 1. A female screw portion 14 to be engaged with the male screw 13a is attached, and the male screw shaft 13 is rotated to displace the slider 12 that is prevented from rotating by means (not shown) in the axial direction. It is configured to be able to approach a distance.

  At the end of the slider 12 in the axial direction center side, a disc-shaped first wall surface portion 15, an outer cylinder portion 16 extending from the outer peripheral side of the first wall surface portion 15 toward the axially outer side, and an outer cylinder A disc-shaped second wall surface portion 17 and a third wall surface portion 18 which are attached to the portion 16 and extend inward in the radial direction of the forming drum are arranged.

  A bead lock driving piston 23 is provided in a space surrounded by the outer cylinder portion 16, the second wall surface portion 17, and the third wall surface portion 18 so as to be capable of reciprocating in the drum axis direction. It acts as a bead lock drive cylinder 25 for reciprocally displacing the bead lock drive block 26 connected to the shaft in the axial direction.

  A large number of bead lock mechanisms 20 are arranged in the circumferential direction, and are guided by a guide 28 provided on the surface of the third wall 18 opposite to the bead lock drive piston 23 so as to reciprocate inward and outward in the radial direction. As a whole, the bead core 1 is fixed to the molding drum 10 when the diameter is expanded and the bead core 1 is opened when the diameter is expanded, and one end is swingably attached to a fixing pin 22a on each bead lock body 21. The other end is composed of a link 22 swingably attached to a fixed pin 22b on the bead lock drive block 24, and the piston 23 is reciprocally displaced in the axial direction. Can be displaced inward and outward in the radial direction.

  The folding mechanism 30 includes a plurality of folding arms 32 arranged at intervals in the circumferential direction so as to be swingable in and out of the molding drum radial direction around a base end portion 31 positioned on the outer side in the molding drum axial direction. A folding roller 33 rotatably provided at the tip, arm moving means 40 for reciprocating the folding arm 32 in the axial direction, and an axially outermost stop position in the axial reciprocating displacement of the folding arm 32 are determined. A pair of stoppers 51 and stopper displacement means 50 for reciprocally displacing the stoppers 51 in the axial direction are provided.

  A disc-shaped fixed piston 19 is mounted on the outer peripheral surface of the slider 12 in the axial direction, and the arm moving means 40 can move in the axial direction on the outer surface of the fixed piston 19 and the slider 12. The movable cylinder 34 is provided with a folding arm 32 that is swingably mounted around the base end 31 thereof.

  The movable cylinder 34 includes an outer cylinder portion 35 provided so that an inner peripheral surface thereof slides with an outer peripheral surface of the fixed piston 19, and wall surface portions 36 and 37 respectively attached to both ends of the outer cylinder portion 35. Yes.

  A stopper drive piston 52 is provided in a space surrounded by the first wall surface portion 15, the second wall surface portion 17, and the outer cylinder portion 16 provided on the center side in the axial direction of the slider 12 so as to be capable of reciprocating in the axial direction. The displacing means 50 includes a stopper driving cylinder 55 constituted by these, a stopper driving piston 52 and a stopper 51, and a stopper connecting cylinder 53 that slides on the outer peripheral surface of the slider 12. The position of the stopper 51 can be switched by reciprocally displacing 52 between two positions in the stopper drive cylinder 55.

  The stopper 51 is configured to be sandwiched between the fixed piston 19 and the axial central side wall surface portion 36 of the movable cylinder 34 at a position on the outer side in the axial direction. The side wall portion 36 slides in the axial direction on the stopper connecting cylinder 53, while the wall surface portion 37 on the outer side in the axial direction of the movable cylinder 34 slides in the axial direction on the outer peripheral surface of the slider 12. ing.

  4 to 7, reference numeral 38 denotes a swing stopper that fixes the posture of the return arm 32 at the swing end where the return roller 33 disposed at the tip of the return arm 32 is closest to the inside in the radial direction. Reference numeral 39 denotes an elastic band made of a material such as rubber and the like, which always applies a force in a direction of swinging radially inward to the folding arm 32.

  A method of molding a tire in which the tire axially opposite ends 83E of the carcass ply 83 are stuck to the radially outer side of the bead core 82 and locked using the tire molding drum 10 having the above-described configuration will be described. When molding a raw tire, first, a carcass band 4 composed of a carcass ply 2 and a cylindrical carcass inner member 3 wider than the carcass ply 2 attached to the inner side in the tire radial direction is formed as a molding drum. Arrange on top (first step).

  Note that, on both side portions of the carcass ply 2, a brazed portion 2 </ b> F is formed in advance that is brazed in a shape that is bent in a hook shape toward the outer peripheral side in a direction facing each other.

  After the first step, the bead cores 1 held by the bead holder 9 are moved from the axially central side to the outside or from the axially outside side to the central side of the molding drum 10, so that the carcass ply 2 The bead lock main body 21 of the bead lock mechanism 20 is expanded in diameter to support the bead core 1 as shown in FIG. The carcass ply 2 is affixed on the inner side in the radial direction 1 (second step).

  In order to increase the diameter of the bead lock body 21 by moving it radially outward, air is supplied to the air chamber 25a (see FIG. 5) in the bead lock drive cylinder 25 to increase the internal pressure and the air chamber 25b (see FIG. 5). 4)), the bead lock driving piston 23 may be displaced to the axially central side by discharging the air, and as a result, the bead lock body 21 connected via the link 22 is displaced radially outward. On the other hand, in order to move the bead lock body 21 radially inward, the air is supplied to the air chamber 25b and the air in the air chamber 25a is discharged to move the bead lock driving piston 23 outward in the axial direction. Displace.

  After the second step, the bead holder 9 is retracted and arranged in the drum radial direction with the base end portion 31 located outside the bead lock mechanism 20 disposed at an interval in the circumferential direction of the molding drum as a center. 5 from the initial state shown in FIG. 5 while contacting the carcass inner member 3 with the folding roller 33 rotatably arranged at the tip of the plurality of folding arms 32 provided in a swingable manner. To the intermediate state shown in the figure, the carcass is moved by translation to the center in the drum axial direction and simultaneously swings outward in the drum radial direction, and then the folding arm is held for a predetermined time in the intermediate state shown in FIG. The brazed portion 2F of the ply is crimped to the outside of the bead core 1 in the tire axial direction (third step).

  The swinging of the folding arm outward in the radial direction in the third step is due to the folding roller 33 disposed at the tip portion being restrained and moved on the inclined surface 21s of the bead lock body 21.

  Further, in order to translate the folding arm 32 from the position corresponding to the initial state to the position corresponding to the intermediate state, the axially outer stop position of the movable cylinder 34 is set by moving the stopper 51 toward the axially central side. What is necessary is just to move to the axial direction center side. In order to move the stopper 51, air is supplied to the air chamber 55a of the stopper drive cylinder 55 and exhausted from the air chamber 55b, so that the stopper drive connected to the stopper 51 via the stopper connecting cylinder 53 is performed. The piston 52 is moved to the axially central side.

  In the tire manufacturing method of the present invention, as described above, the folding roller 33 is stopped in an intermediate state, and the carcass ply brace portion 2F is bent around the bead core 1 and the folding roller 33 is in the middle. It is characterized in that the bent portion 2F bent by holding the crimped state for a predetermined time in the state is firmly crimped to the bead core 1, and thus, between the bead core 1 and the carcass ply brazed portion 2F. It is possible to prevent air from entering and causing poor air entry.

  The tire molding drum according to the present invention is characterized in that it includes a stopper 51 and a stopper displacing means 50 for reciprocally displacing the stopper 51 which are not provided in the prior art. Can be realized.

  After the third step, as shown in FIG. 7, the male screw shaft 13 is rotationally driven to move the sliders 12 on both sides toward the center in the axial direction. The central portion of the carcass band 4 spanned between the two bead cores 1 is expanded in a toroidal shape while being brought close to each other (fourth step).

  In order to cause the central portion of the carcass band 4 to bulge, air is supplied to the space inside the central portion of the carcass band 4 in the radial direction. At this time, the bead lock bodies 21 that are divided and arranged in the circumferential direction are mutually connected. A sealing member 29 made of an elastic material such as rubber is provided so that air does not leak from the gap.

  After the fourth step, while the folding roller 33 is in contact with the carcass inner member 3, the folding arm 32 is further translated and moved to the center side in the drum axial direction so that both sides of the carcass ply inner member 2 are bead core 1. Fold it around (fifth step).

  In order to displace the folding arm 32 from the axial position corresponding to the intermediate state further to the axial center side, air is supplied to the air chamber 34a (see FIG. 7) in the movable cylinder 34 of the arm moving means 40 and the air is moved. By exhausting air from the chamber 34b (see FIG. 7), the movable cylinder 34 is displaced toward the center in the axial direction relative to the fixed piston 19.

  In order to return the folding arm 32 to the initial state, the stopper driving piston 52 is moved outward in the axial direction by supplying air to the air chamber 55b and discharging air from the air chamber 55a, and then returns to the air chamber 34b. This can be realized by moving the movable cylinder 34 outward in the axial direction by supplying air and discharging the air from the air chamber 34a.

  In the example described above, the fourth step is arranged after the third step. However, the third step can be arranged after the fourth step. In any case, the conventional manufacturing method can effectively suppress the air entering between the bead core 1 and the brazed portion 2F of the carcass ply, but more effectively suppress the air entering. In terms of what can be done, the fourth step is preferably arranged after the third step.

  The present invention can be suitably used particularly for heavy-duty vehicle tires such as trucks and buses.

It is sectional drawing which shows the bead part of the tire used as the object of this invention. It is sectional drawing which shows the bead part of the green tire in the middle of formation in the conventional manufacturing method. It is sectional drawing which shows the bead part of the green tire in the middle of the formation in the process following the process shown in FIG. 2 in the conventional manufacturing method. It is sectional drawing which shows the quarter part of the tire molding drum of embodiment which concerns on this invention. FIG. 5 is a cross-sectional view showing a quarter portion of the tire molding drum in the operating state after being shown in FIG. 4. It is sectional drawing which shows the quarter part of the tire shaping | molding drum in the operation state after shown in FIG. It is sectional drawing which shows the quarter part of the tire shaping | molding drum in the operation state after shown in FIG.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Bead core 2 Carcass ply 2F Carcass ply attaching part 3 Carcass inner member 4 Carcass band 9 Bead holder 10 Tire 11 Main shaft 12 Slider 13 Male thread shaft 13a Male thread 14 Female thread part 15 First wall part 16 Outer cylinder part 17 Second wall part 18 First Three wall surfaces 19 Fixed piston 20 Bead lock mechanism 21 Bead lock body 22 Link 22a, 22b Fixed pin 23 Bead lock drive piston 25 Bead lock drive cylinder 25a, 25b Air chamber 26 Bead lock drive block 28 Guide 30 Folding mechanism 31 Folding arm 31 Base end portion 32 Folding arm 33 Folding roller 34 Movable cylinders 34a, 34b Air chamber 35 Outer cylinder portion 36 Axial central side wall surface portion of movable cylinder 37 Axial outer wall surface of movable cylinder 38 swing stopper 39 elastic bands 40 arm moving means 50 stop displacement means 51 stopper 52 stopper driving piston 53 stopper coupling tube 55 stopper drive cylinder 55a, 55b air chamber

Claims (4)

A carcass ply comprising one or more steel cords spanned between a pair of bead parts and turned around from a bead core disposed in each bead part from the inner side to the outer side in the tire axial direction. In the method for manufacturing a pneumatic tire, both axial ends are stuck and locked to the outside in the radial direction of the corresponding bead cores.
Prior to vulcanization of the tire, when the green tire is molded, the brazed portions that are formed in a cylindrical shape and are bent in a hooked shape toward the outer periphery in the direction facing each other are attached to both ends in the tire axial direction. A first step of disposing on a molding drum a carcass band composed of a carcass ply having a portion and a cylindrical carcass inner member wider than the carcass ply attached to the inner side in the tire radial direction;
After the first step, each bead core held by the bead holder is disposed at a predetermined position on the center side in the tire axial direction from the brazed portion of the carcass ply, and the bead lock mechanism is expanded to support the bead core. A second step of attaching a carcass ply to the inner side in the radial direction of these bead cores;
After the second step, the bead holder is retracted and swings inward and outward in the drum radial direction centered on a base end portion located on the outer side in the drum axial direction with respect to the bead lock mechanism and spaced apart in the circumferential direction of the molding drum. A plurality of fold-back arms provided in a movable manner are arranged in a drum axial direction from a predetermined initial state to an intermediate state, respectively, while a fold-back roller rotatably disposed at the tip thereof is brought into contact with the carcass inner member. At the same time as being translated to the center side and simultaneously swinging outward in the drum radial direction, and then holding the folding arm in the intermediate state for a predetermined time, the brazed portion of the carcass ply is moved outward in the tire axial direction of the bead core. A third step of crimping;
After the second step, a fourth step of bulging the center part of the carcass band spanned between the bead cores in a toroidal manner while making the bead lock mechanisms on both sides approach each other;
After the third step and the fourth step, the both sides of the carcass ply inner member are moved by translating the folding arm further to the drum axial center side while keeping the folding roller in contact with the carcass inner member. And a tire manufacturing method comprising a fifth step of turning the bead core around the bead core.   The tire manufacturing method according to claim 1, wherein the fourth step is arranged after the third step. A tire molding drum used in the tire manufacturing method according to claim 1 or 2,
A main shaft that rotates on the axis of a molding drum and rotates the carcass band, a pair of bead lock mechanisms that are disposed around the main shaft on both outer sides in the axial direction and that support and fix a bead core from the inner side in the radial direction, and the bead lock mechanism A pair of folding mechanisms arranged around the main shaft on both outer sides in the axial direction and folding back both sides of the carcass band, and the bead lock mechanism and the folding mechanism are mounted one by one, and the main shaft is separated from each other. Comprising a pair of sliders configured to,
The folding mechanism includes a plurality of folding arms provided so as to be capable of swinging in and out of the radial direction of the forming drum with a base end portion positioned on the outer side in the axial direction as a center, and a folding roller disposed rotatably at a distal end portion thereof. Arm moving means for reciprocating the folding arm in the axial direction, a pair of stoppers for determining the outermost stop position in the axial direction in the axial reciprocation of the folding arm, and the stoppers in the axial direction Stopper displacement means for reciprocating displacement,
These stopper displacing means are tire molding drums configured to displace the stopper to positions where the folding arms can be positioned at respective stop positions corresponding to the initial state and the intermediate state. The slider has an outer peripheral surface and is configured to be able to slide on the main shaft in the axial direction.
The stopper displacing means is composed of a stopper connecting cylinder that connects the driving cylinder and the stopper disposed on the center side in the axial direction from the stopper and slides on the outer peripheral surface of the slider.
The arm moving means includes a fixed piston fixed on the outer peripheral surface of the slider, a movable cylinder provided on the slider so as to be movable in the axial direction, and having a base end portion of the folding arm attached to be swingable. Consists of
The movable cylinder is composed of an outer cylindrical portion provided so that an inner peripheral surface slides on an outer peripheral surface of the fixed piston, and wall surface portions respectively attached to both ends of the outer cylindrical portion. The wall portion on the axial center side is configured to slide on the stopper connecting cylinder,
4. The tire molding drum according to claim 3, wherein the stopper is arranged to be sandwiched between the fixed piston and an outer wall portion on the central side in the axial direction in the axially outermost position state of the movable cylinder. .

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