JP2000202924A - Manufacture of pneumatic tire - Google Patents

Abstract

PROBLEM TO BE SOLVED: To effectively prevent the middle of an intermediate band from axially shifting to a tire forming drum. SOLUTION: The axially middle part of an intermediate band 12 locating between bead cores 18 is kept on being attracted and held with a permanent magnet 32 at the locking of the bead cores 18 from radially inside through the diametrically expanding bead locking bodies 17. Thus, even when the axial tensile force is given to the intermediate band 12 due to the difference between the diametrically expanding speed of a pair of the bead locking bodies 17, the axial displacement of the intermediate band 1 is restricted from occurring by means of the attracting holding force caused by the permanent magnet 32.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method of manufacturing a pneumatic tire in which a cylindrical intermediate band and a bead core are supplied to a tire building drum to perform tire building.

[0002]

2. Description of the Related Art Conventionally, pneumatic tires have been manufactured, for example, as follows. That is, a cylindrical intermediate band formed by a band forming drum, and a pair of bead cores respectively arranged radially outside the intermediate band, are conveyed to a tire forming drum while being held by a transfer device, and the intermediate band To the outside of the tire building drum.

[0003] Thereafter, by expanding the diameter of the bead locks provided on both sides in the axial direction of the tire building drum, the bead cores are respectively locked from the radially inner side by the bead locks via intermediate bands. During the locking operation, the intermediate band is released from being held by the transfer device at the same time as the expansion of the bead lock body starts. Next, after the transfer device is retracted from the tire building drum, air is supplied into the intermediate band between the bead lock bodies while approaching the bead lock bodies, and the center in the axial direction of the intermediate band located between the bead cores is radiused. The intermediate band is bulged outward in the axial direction, and both ends in the axial direction of the intermediate band located axially outward from the bead core are turned outward in the radial direction.

[0004]

However, in such a conventional method for manufacturing a pneumatic tire, as described above, the expansion of the beadlock body is started, and at the same time, the intermediate band is released from being held by the transfer device. Because it is released, the intermediate band becomes free during the expansion of the beadlock. Here, the expanding speed of the paired bead lock bodies may be slightly different due to a difference in friction resistance between the two, but in such a case, the bead lock body side having the larger expanding speed of the intermediate belt is used. Since the intermediate band is lifted from the tire building drum in advance, the free intermediate band is pulled toward the bead lock body having a large diameter expanding speed and is displaced in the axial direction. There is a problem that displacement occurs.

An object of the present invention is to provide a method of manufacturing a pneumatic tire that can effectively prevent axial displacement of an intermediate band with respect to a tire building drum.

[0006]

SUMMARY OF THE INVENTION An object of the present invention is to provide a method of manufacturing a pneumatic tire as described above, wherein when the bead core is locked by a bead lock, an axial center portion of an intermediate band is held by a transfer device. This can be achieved by suction holding from the outside by a member and limiting displacement of the intermediate band in the axial direction.

In the present invention, when each of the pair of bead cores is locked by the bead lock body, the central portion in the axial direction of the intermediate band is suction-held from outside by the holding member of the transfer device. Even if an axial tensile force is applied to the intermediate band due to the difference in the diameter expansion speed of the intermediate band, the axial displacement of the intermediate band is limited by the suction holding force of the holding member, whereby the tire forming drum of the intermediate band is Is effectively prevented.

[0008] According to the second aspect of the present invention, the intermediate band can be repeatedly adsorbed semipermanently with a large adsorbing force. Further, according to the structure of the third aspect, the adsorption to the intermediate band becomes strong, and the center shift can be reliably prevented.

[0009]

DESCRIPTION OF THE PREFERRED EMBODIMENTS One embodiment of the present invention will be described below with reference to the drawings. In FIGS. 1, 2, and 3, reference numeral 11 denotes a cylindrical band forming drum capable of expanding and contracting diameter, and the band forming drum 11 is driven and rotated around a horizontal axis by a driving mechanism (not shown). Then, tire components such as an inner liner, a side tread, a carcass ply, a wire chafer, and a rubber chafer are supplied one after another from a supply device (not shown) to the rotating band forming drum 11, and are attached to the periphery, A cylindrical intermediate band 12 is formed around the band forming drum 11. Here, this intermediate band 12 is, as shown in FIG.
A central band portion 12a made of an inner liner, a carcass ply, or the like, and a pair of outer band portions 12b and c made of a side tread, with an axial inner end joined to an axial outer end of the central band portion 12a. , The central band section 12
a has a pair of cushion rubbers 13 wound around the outer periphery of the central portion in the axial direction so as to be spaced apart in the axial direction.

Reference numeral 16 denotes a cylindrical tire forming drum disposed in front of the band forming drum 11. The tire forming drum 16 is driven by a drive mechanism (not shown).
It rotates around an axis that is coaxial with the band forming drum 11. Further, the tire building drum 16 has a pair of bead lock bodies 17 spaced apart in the axial direction.
17 is usually the same diameter as the tire building drum 16, but when the bead core 18 is conveyed to the outside as shown in FIG. 4, it is possible to expand the diameter and lock the bead core 18 from the radial inside. it can. Furthermore, this tire building drum
As shown in FIG. 5, 16 has folding bladders 19 and 20 that can expand and contract in the axial direction outside of the bead lock body 17, respectively. When these folding bladders 19 and 20 are inflated,
Both ends in the axial direction of the intermediate band 12 located outside the bead core 18 in the axial direction are turned around the bead core 18 radially outward.

A pair of guide rails 25 are laid on a floor surface 24 between the band forming drum 11 and the tire forming drum 16, and these guide rails 25 are connected to the band forming drum.
It extends parallel to the 11 axes. Reference numeral 26 denotes a transfer device for transferring the intermediate band 12 from the band forming drum 11 to the tire forming drum 16, and the transfer device 26 has a movable bearing having a slide bearing 27 attached to the lower surface so as to be slidably engaged with the guide rail 25. It has a frame 28. An upright central support means 29 is provided at the center of the upper surface of the movable frame 28, and the central support means 29 has a ring-shaped support ring 30 which is coaxial with the band forming drum 11, and is radially attached to the support ring 30. And a plurality of holders 31 movably supported. These holders 31 are spaced equidistantly in the circumferential direction, and have an arc-shaped body 33 to which a permanent magnet 32 as a holding member is attached at an inner end in the radial direction.

Reference numeral 34 denotes a cylinder connected to the support ring 30. The tip of a piston rod 35 of the cylinder 34 is connected to the holder 31 via a link mechanism 36. Here, when the piston rod 35 of the cylinder 34 projects,
All the holders 31 move inward in the radial direction in synchronization with each other, and are buried in the axial center part (central band part 12a) of the intermediate band 12 formed by the band forming drum 11, specifically, in the carcass ply of that part. Steel cord is permanent magnet
The suction is carried out from the outside in the radial direction by 32. And
When the holding member is constituted by the permanent magnet 32 as described above, the intermediate band 12 can be repeatedly and semi-permanently attracted with a large attraction force.

Here, the permanent magnets 32 are arranged at three places separated in the axial direction, and more specifically, as shown in FIG.
A central permanent magnet 32a is provided at the axial center of the
The front and rear permanent magnets 32b, c are arranged at the axial front and rear sides of 33, respectively. As a result, the intermediate band 12 between the cushion rubbers 13 by the central permanent magnet 32a,
The front and rear permanent magnets 32b and c respectively hold and hold the intermediate band 12 outside the cushion rubber 13 in the axial direction. If the permanent magnets 32 are set apart from each other in the axial direction and the intermediate bands 12 between the cushion rubbers 13 and on both sides of the cushion rubbers 13 are respectively adsorbed, the intermediate magnets can be spread over a wide area excluding the cushion rubbers 13. The band 12 can be adsorbed, whereby the adsorption to the intermediate band 12 can be enhanced. The above-described support ring 30, holder 31, permanent magnet 32, arc-shaped body 33, cylinder 34,
The link mechanism 36 as a whole constitutes the central support means 29 for sucking and holding the axial center portion of the intermediate band 12 from the outside.

The front and rear ends of the movable frame 28 are also provided with front and rear support means 41 and 42 having substantially the same structure as the central support means 29 at the front and rear ends thereof. The holding members of the side supporting means 41 and 42 are for holding the axial end portions of the intermediate band 12 (the outer band portions 12b and c formed of the rubber-only side treads) by suction. Instead of the permanent magnets, they are constituted by conical suction pads 43 and 44 connected to a vacuum source as shown in FIG. These front and rear support means 41, 42
When the permanent magnet 32 of the central support means 29 sucks and holds the central portion of the intermediate band 12 in the axial direction, the suction pads 43 and 44 simultaneously suck and hold both axial ends of the intermediate band 12 from the outside in the radial direction.

A plurality of expandable and contractible holders 45 and 46 are respectively supported on the inner surfaces of the front and rear support means 41 and 42 facing each other, and a stiffener 47 is provided on the radial inner ends of these holders 45 and 46. A plurality of magnets 49 for attracting the attached bead core 18 are embedded. And the transfer device 26
Is in a standby position between the band forming drum 11 and the tire forming drum 16, the bead core 18 with the stiffener 47 is supplied from a bead supply device (not shown) to the holders 45 and 46 in the reduced diameter state.

Next, the operation of the embodiment of the present invention will be described. When manufacturing a pneumatic tire, here a pneumatic radial tire for heavy load, using the tire manufacturing equipment as described above, first, an inner liner, a side tread, a carcass ply, a wire are attached to a rotating band forming drum 11. Tire components such as chafers, rubber chafers, cushion rubbers, etc. are supplied one after another and wound around them to form a cylindrical intermediate band 12.
At this time, the cushion rubber 13 slightly rises from the outer peripheral surface of the central band portion 12a at the central portion in the axial direction of the intermediate band 12. When the intermediate band 12 is formed by the band forming drum 11 in this manner, the stiffener 47 is supplied to the transfer device 26 at the standby position by the bead supply device.
The bead core 18 with
The magnets 49 of 5 and 46 attract and hold, respectively.

Next, the transfer device 26 is moved rearward along the guide rail 25 by a drive mechanism (not shown), and the band forming drum 11 is surrounded by the transfer device 26 from the outside in the radial direction. Next, the central support means 29,
Activate the cylinder 34 of the front and rear support means 41, 42 to hold the holder.
31 is synchronously moved inward in the radial direction. Thereby, the permanent magnet 32 of the central support means 29 is
12a, in detail, the central permanent magnet 32a is cushion rubber
13 and the front and rear permanent magnets 32
b and c respectively suck and hold the central band portion 12a axially outside the cushion rubber 13, while the suction pads 43 and 44 of the rear support means 41 and 42 before and after the evacuation are performed. c is held by suction. At this time, the diameter of the band forming drum 11 is reduced, whereby the intermediate band 12
Is transferred from the band forming drum 11 to the transfer device 26. When the intermediate band 12 is thus transferred to the transfer device 26, the bead core 18 held by the holders 45 and 46 is arranged at a predetermined position on the radial outside of the intermediate band 12.

Next, the transfer device 26 is moved forward along the guide rail 25 to a position where the transfer device 26 surrounds the tire forming drum 16 from the outside in the radial direction. Thereby, the intermediate band 12 and the bead core 18 held by the transfer device 26 are transported to the tire building drum 16 as shown in FIG.
Outside. Here, the transfer device
The movement of 26 stops when each of the bead cores 18 has reached the radially outer side of the bead lock body 17. Next, by expanding the diameter of the bead lock body 17 of the tire building drum 16, the bead cores 18 are locked from the radial inside by the bead lock bodies 17 via the intermediate bands 12, respectively.

At the same time as the expansion of the bead lock body 17,
The suction pads 43, 44 of the rear support means 41, 42 are moved radially outward to retract from the intermediate band 12, and the suction pads 43, 44 are cut off from the vacuum source, so that the outer band portions of the intermediate band 12 are removed. 12b, c front and rear support means 41, 42
From the tire forming drum 16. On the other hand, the central portion of the intermediate band 12 located between the bead cores 18 in the axial direction, in this case, the permanent magnet 32 holding the central band portion 12a by suction is held at the same position. The suction holding of the permanent magnet 32 from the outside of the permanent magnet 32 is continued even when the diameter of the bead lock body 17 is expanded.

As a result, even if the tensile force in the axial direction is applied to the intermediate band 12 due to the difference in the expanding speed of the pair of bead locks 17, the attractive force of the permanent magnet 32 causes the intermediate band 12 to move in the axial direction of the intermediate band 12. The displacement of
An axial center displacement of the intermediate band 12 with respect to the tire building drum 16 is effectively prevented. Also, when a pair of slightly protruding cushion rubbers 13 are wound around the outer periphery of the intermediate band 12 as in this embodiment, the central permanent magnet
The intermediate band 12 between the cushion rubbers 13 is provided by 32a, and the cushion rubber is provided by the front and rear permanent magnets 32b and 32c.
If the intermediate bands 12 that are axially outward from the intermediate band 12 are held by suction, the suction to the intermediate band 12 will be strong, and the center displacement as described above can be reliably prevented.

The suction holding of the central band portion 12a by the permanent magnet 32 ends when the lock of the bead core 18 by the bead lock body 17 is completed. At the same time, the cylinder 34 of the central support means 29 is operated. By actuating, the holder 31 and the permanent magnet 32 are synchronously moved radially outward. Thereby, the remaining portion of the intermediate band 12, that is, the central portion in the axial direction is transferred from the central support means 29 to the tire building drum 16. Next, by expanding the diameter of the holders 45 and 46, the bead core 18 is expanded.
Then, the transfer device 26 is moved rearward to the standby position and retracted from the tire building drum 16.

Next, as shown in FIG.
Intermediate band between these while bringing 17 closer together
Air is supplied into the inner band 12 to radially outwardly bulge the axial center portion of the intermediate band 12 located between the bead cores 18 and expand the folded bladders 19 and 20 to expand the intermediate band axially outside the bead core 18. The 12 axial ends are folded outward in the radial direction. At this time, a belt / tread band 51 formed in advance by a band drum (not shown) is carried in a radially outer side of the bulged intermediate band 12 and bonded to each other to form a green tire. Next, after taking out the green tire from the tire building drum 16, it is vulcanized by a vulcanizing device to produce a pneumatic radial tire for heavy loads.

[0023]

As described above, according to the present invention, axial displacement of the intermediate band with respect to the tire building drum in the axial direction can be effectively prevented.

[Brief description of the drawings]

FIG. 1 is a schematic front view showing an embodiment of the present invention.

FIG. 2 is a view taken in the direction of arrows II in FIG. 1;

FIG. 3 is a partially broken perspective view showing a state in which a bead core is held by a holder.

FIG. 4 is a partially cutaway front view illustrating the operation of the present invention.

FIG. 5 is a partially cutaway front view illustrating the operation of the present invention.

[Explanation of symbols]

11: Band forming drum 12 ... Intermediate band 13 ... Cushion rubber 16 ... Tire forming drum 17 ... Bead lock body 18 ... Bead core 26 ... Transfer device 32 ... Holding member (permanent magnet)

Claims (3)

[Claims] A cylindrical intermediate band formed by a band forming drum and a pair of bead cores disposed outside the intermediate band are transported to a tire forming drum by a transfer device, and the intermediate band is transferred to the tire forming drum. Externally fitting, expanding the bead lock body provided on the tire forming drum, locking the bead cores from the radially inner side with the bead lock bodies via intermediate bands, respectively, After retracting from the forming drum, air is supplied into the intermediate band between the bead lock bodies while approaching the bead lock bodies, and the central portion in the axial direction of the intermediate band located between the bead cores is bulged radially outward. , The both ends in the axial direction of the intermediate band located outside the bead core in the axial direction are radially outside. Turning the bead core by a bead lock body, wherein the central part of the intermediate band in the axial direction is suction-held from outside by a holding member of a transfer device, and the intermediate band A method for manufacturing a pneumatic tire, characterized in that displacement in the axial direction is limited. 2. The method for manufacturing a pneumatic tire according to claim 1, wherein said intermediate band is attracted and held by a holding member formed of a permanent magnet. 3. When the intermediate band has a pair of cushion rubbers on the outer periphery of a central portion in the axial direction, the holding members are arranged at three positions separated in the axial direction, and the intermediate members between the cushion rubbers are arranged by these holding members. 2. The method for manufacturing a pneumatic tire according to claim 1, wherein the band and the intermediate band axially outside the cushion rubber are held by suction.