JPS6260982B2 - - Google Patents

Description

[Detailed description of the invention] The present invention relates to a tire forming former.

The usual molding method for automotive radial tires is
It consists of primary forming, in which carcass plies and bead wires are bonded together in a cylindrical shape, and secondary forming, in which the resulting cylindrical primary formed green tire is transformed into a toroidal shape and a belt, tread cap, etc. are bonded to its outer surface. As a tire forming former for carrying out this secondary forming, those shown in FIGS. 1 and 2 are known. That is, it is equipped with a pair of left and right disks 1, 1 and belt rings 2, 2 that are slidable along a horizontal main axis (not shown), and as shown in FIG. 1,1
The discs 1, 1 are placed close to the center and the belt rings 2, 2 are placed on standby on the left and right sides.
From the side, a cylindrical primary molded green tire G
, and then slide the discs 1, 1 symmetrically laterally to the position indicated by the two-dot chain line 1, 1 to remove the rim 1.
The bead part of the primary molded green tire G is shown in a and 1a.
The inner surfaces of the tires G are fitted together, and then the belt rings 2, 2 are brought close together to a predetermined position as shown in FIG. By bringing the left and right disks 1, 1 close to each other while feeding, the primary formed green tire G is expanded and deformed into a toroidal shape, and its top Gb slightly protrudes from the gap between the tips of the left and right belt rings 2, 2. Then, a plurality of belts S, S and tread cap T are successively stacked in an endless manner across the left and right belt rings 2, 2, and these are crimped by a pair of left and right staple rollers 3, 3. After the left and right belt rings 2, 2 are returned to the left and right standby positions, the staple rollers 3, 3 are driven again to remove the inner surface of the lowermost belt S and the lower surface of the side edge of the tread cap T. Primary molding green tire G
It is designed to be attached by crimping it to the outside surface of the

However, in the conventional tire molding former, the rim 1a of the disc 1 for holding the bead portion Ga of the primary molded green tire G is attached to the bead portion Ga.
Since it is formed so as to contact only the inner surface of Ga, when the disks 1 and 1 are brought close to each other in order to deform the primary green tire G into a toroidal shape, the cross-sectional shape of the primary green tire G is almost halved. If you try to bring the outer surface of the primary molded green tire G into contact with almost the entire inner surface of the bottom layer belt S by bringing it close to the point where it becomes an Ω-shape rather than an arc shape (see Fig. 5). , due to the rigidity of the sidewall portion Gc of the primary molded green tire G and the filling air pressure, an outward thrust is generated in the bead portion Ga, resulting in the bead portion Ga coming off from the rim 1a of the disc 1, Therefore, the close proximity of the disks 1, 1 was kept to such an extent that the cross-sectional shape of the primary molded green tire G was approximately semi-circular as shown in FIG.
Therefore, when the belt rings 2, 2 are returned to the left and right standby positions, the vertical distance h between the side edge of the lowermost belt S and the primary formed green tire G increases,
When the staple rollers 3, 3 are crimped, the belts S, S and the tread cap T are greatly deformed, resulting in increased wrinkles and a decrease in the uniformity of the product tire.

The present invention provides a tire forming former capable of deforming a primary molded green tire into an Ω-shaped cross section, and also capable of easily attaching and detaching the primary molded green tire.

That is, the present invention provides a tire molding former in which a pair of left and right bead holding discs each having a rim formed in a shape that follows the inner surface of a bead portion of a primary molded green tire is provided so as to be slidable in the axial direction. A support drum concentric with the main shaft is formed integrally with the bead holding disk on the outside in the axial direction of each holding disk, and an endless tube-shaped diaphragm made of a rubber-like elastic body is attached to the outer surface of this support drum. A large number of bead holding segments each having a rim shaped to follow the outer surface of the bead portion of the primary molded green tire are disposed in a ring shape around the outer periphery of the shaped diaphragm and are slidable in the radial direction. As the shaped diaphragm expands and contracts, the bead retaining segment is slid in the radial direction such that at the outer end of its stroke, the diameter of the rim of the bead retaining segment matches the diameter of the rim of the bead retaining disc. This is a characteristic tire molding former.

Embodiments of the present invention will be described below with reference to FIGS. 3 to 5.

In FIG. 3, the hollow main shaft 4 is rotatably supported at its right drive side end (not shown), and a hollow air supply pipe 5 is inserted into the center hole 4a from the drive side end. A plug 6 airtightly fitted to the free end side of the main shaft 4 is connected to the tip of the air supply pipe 5, and a ventilation hole 6a formed in the plug 6 and a vent hole 6a formed in the main shaft 4 are connected to the tip of the air supply pipe 5. The outer surface of the main shaft 4 and the center hole 5a of the air pipe 5 are communicated through the air passage 4b. The plug 6 has a cylindrical part 6b concentric with the main shaft 4, and the tip of the tail stock shaft 7, which is slidably provided to the left of the main shaft 4, is attached inside the cylindrical part 6b. By inserting the main shaft 4 and the tail stock shaft 7, the main shaft 4 and the tail stock shaft 7 are connected. Note that a ventilation hole 4c is provided on the drive side of the main shaft 4 to communicate the outer surface of the main shaft 4 with the inside of the center hole 4a.

An inner sleeve 8 is fitted onto the outer surface of the main shaft 4, and the drive side ends of the two are slidably and non-rotatably connected, and a bush 9 is fixed to the inner surface of the free end of the inner sleeve 8. It is slidably fitted onto the main shaft 4. A support drum 10 is fixed to the outer surface of the free end of the inner sleeve 8 by a nut 11, and a boss portion 1 of the support drum 10 is fixed to the outer surface of the free end of the inner sleeve 8.
A bead holding disk 12, which is substantially similar to the conventional bead holding disk 1, is fixed to the axially inner end of the support drum 10, and an endless tube-shaped diaphragm 13 made of a rubber-like elastic body is attached to the outer surface of the rim portion 10b of the support drum 10. The internal space is formed by a ventilation path 10c formed in the support drum 10, a ventilation path 8a formed in the inner sleeve 8, the inner surface of the inner sleeve 8, the outer surface of the bush 9 on the driving section side, and the outer surface of the main shaft 4. It communicates with the center hole 4a of the main shaft 4 through an annular ventilation passage 9a formed between the main shaft 4 and the ventilation hole 4c of the main shaft 4. A large number of segment-shaped sliding saddles 14 (see FIG. 4) are arranged along the outer periphery of the tube-shaped diaphragm 13 in a ring shape so as to be freely slidable in the radial direction. This sliding saddle 1
Reference numeral 4 includes a body portion 14a that forms a part of a cylinder when the tubular diaphragm 13 is contracted, and a flange portion 14b that projects outward in the radial direction, and a coil connected endlessly to the outer surface of the body portion 14a. The sliding saddle 14 is fitted with springs 15, 15.
The flange portion 14b has a rim shaped to face the rim 12a of the bead holding disk 12 and to follow the outer surface of the bead portion Ga of the primary green tire G. A bead retaining segment 16 with 16a is secured. A step portion 12b is protruded from the bead holding disc 12, a stopper 17 is fixed to the outer end of the body portion 14a of the sliding saddle 14 in the axial direction, and the tube-shaped diaphragm 13 is connected to the coil springs 15, 1.
When the step part 12 expands against the elasticity of the part 5, the step part 12
The stopper 17 engages the axially inner end of the body 14a of the sliding saddle 14 and the axially outer end of the rim 10b of the support drum 10 at b, thereby adjusting the diameter of the rim 16a of the bead holding segment 16. is set to be equal to the rim 12a of the bead holding disc 12. Note that the inner sleeve 8 has a ventilation hole 8 located axially inward of the bead holding disk 12.
b is bored, and this ventilation hole 8b connects to an annular ventilation passage 9 cut into the surface of the free end side of the bush 9.
b. Through a radial ventilation hole 9c drilled in the center of the bush 9, an annular ventilation passage 9d cut on the inner surface of the drive side of the bush 9, the ventilation passage 4b of the main shaft 4, and the ventilation hole 6a of the plug 6. It is communicated with the air pipe 5 mentioned above.

An outer sleeve 18 is fitted onto the driving portion side of the inner sleeve 8, and the driving side ends of the inner sleeve 8 are slidably and non-rotatably connected, and a bushing is fixed to the inner surface of the free end side of the outer sleeve 18. 1
9 is slidably fitted on the outer surface of the inner sleeve 8, and the boss portion 20 of the support drum 20 is connected to the free end of the outer sleeve 18 via a connecting ring 18A.
a is connected to the boss portion 20a, and a bush 2 that is slidable with respect to the inner sleeve 8 is provided on the inner surface of the boss portion 20a.
1 is fixed. The support drum 20 described above is formed symmetrically with respect to the left free end support drum 10 except for the structure of the boss portion 20a. A tube-shaped diaphragm 23 is attached to each of the rim portions 10b, and the tube-shaped diaphragm 23 connects to the ventilation passage 20 bored in the support drum 20.
c. Air passage 21a bored in bush 21, inner cavity of connecting ring 18A, outer sleeve 18
An axial ventilation hole 19a bored in the free end of the bush 19, an annular ventilation passage 19b cut into the inner surface of the bush 19, and an inner sleeve 8.
The inner sleeve 8 is connected to a ventilation passage 9a inside the inner sleeve 8 through a ventilation hole 8c formed on the driving portion side of the inner sleeve 8.
In addition, 22a is a rim, 22b is a step part, 24 is a sliding saddle, 24a is a body part, 24b is a flange part, 2
5 is a coil spring, 26 is a bead holding segment, 26a is a rim, and 27 is a stopper, which are formed symmetrically with respect to the free end side.

In the above structure, the left and right tubular diaphragms 13 and 23 are respectively contracted to position the bead holding segments 16 and 26 at their radially inner ends, and the inner sleeve 8 is moved to the right and the outer sleeve 18 is moved to the left. The left and right bead holding discs 12 and 22 are brought close to each other by sliding them respectively.
Furthermore, the tail stock shaft 7 is uncoupled from the main shaft 4 and left on standby, and in this state, the primary molded green tire G is inserted into the bead holding disc in the close state from the free end side of the main shaft 4 which has been uncoupled. 12, 22
Charge to. Next, the above tail stock shaft 7
After sliding the inner sleeve 8 to the right and connecting it to the main shaft 4, move the inner sleeve 8 to the left and the outer sleeve 18.
The left and right bead holding discs 12, 22 are moved to the solid line positions in FIG. mate. After that, compressed air is supplied to the main shaft 4 from the drive side end of the main shaft 4.
The compressed air is supplied to the ventilation path 9a between the main shaft 4 and the inner sleeve 8 through the center hole 4a and the ventilation hole 4c, and a part of this compressed air is supplied to the ventilation path 8a of the inner sleeve 8 and the ventilation path 10c of the left support drum 10. The other part of the compressed air is sent to the left tube-shaped diaphragm 13 through the ventilation passage 8c of the drive unit side of the inner sleeve 8, the ventilation passage 19b of the bush 19 of the outer sleeve 18, the ventilation hole 19a, and the connecting ring. 18A, the ventilation hole 21a of the bush 21 for the right support drum 20, and the support drum 2
0 to the right tubular diaphragm 23 through the ventilation hole 0c, thereby inflating the left and right tubular diaphragms 13, 23, and the left and right bead holding segments 16, 26 through the sliding saddles 14, 24, respectively. The rims 16a and 26a are pushed outward in the radial direction and brought into contact with the axially outer surface of the bead portion Ga of the primary molded green tire G.
At this time, even if there is a distortion in the shape of the bead portion Ga, this distortion is absorbed by the tube-shaped diaphragms 13 and 2.
3, so the bead part Ga and the rim 16
A and 26a, there is no gap between them. In this way, the bead portion Ga is attached to the bead holding disk 1.
2, 22 and the rims 16a, 26a of the bead holding segments 16, 26, the belt rings 2, 2 (see FIG. 2) are held in place as in the conventional case. The left and right bead holding discs 12, 2 are brought close to each other and the inner sleeve 8 and outer sleeve 18 are slid together.
2 and bead holding segments 16 and 26 close to each other, compressed air is supplied from the air pipe 5 to the ventilation hole 6a of the plug 6, the ventilation path 4b of the main shaft 4, the drive side ventilation path 9d of the bushing 9 for the inner sleeve 8, and the central part. into the space surrounded by the left and right bead holding discs 12, 22 and the primary formed green tire G through the ventilation hole 9c, the free end side ventilation path 9b, and the free end side ventilation hole 8b of the inner sleeve 8. As a result, the primary molded green tire G is transformed into the shape shown in FIG. 2, and the belts S, S and tread cap T are laminated on the left and right belt rings 2, 2, and the staple rollers 3, 3 are crimped. Next, after returning the belt rings 2, 2 to the standby position, the inner sleeve 8 and outer sleeve 18 are slid again, and the left and right bead holding discs 12, 22 and bead holding segments 16, 26 are moved as shown in FIG. By approaching the belt to the position , the primary molded green tire G having a semicircular arc cross section is deformed into an Ω-shape cross section, and its outer surface is brought into pressure contact with almost the entire inner surface of the belt S. At this time, the outer surface of the bead portion Ga of the primary molded green tire G is
Since it is locked by the rims 16a and 26a of 6,
The bead portion Ga mentioned above will not come off. Therefore, when the staple rollers 3, 3 are pressed together again, the deformation of the belts S, S and tread cap T is much smaller than in the past, and therefore the uniformity of the product tire is significantly improved. Moreover, when first placing the left and right bead holding discs 12, 22 close together and charging the primary molded green tire G, the bead holding segments 16, 26 are located at the inner ends in the radial direction, so the can be easily charged in the same way as before. When the belts S, S and tread cap T are attached and the secondary forming is completed, the compressed air from the left and right tube-shaped diaphragms 13, 23 is discharged, and the sliding saddles 14, 24 are moved by the elasticity of the springs 15, 25. The bead retaining segments 16, 26 are then returned to the inner end of their stroke and disengaged from the outer surface of the bead portion Ga. The green tire obtained by the above secondary forming has left and right bead holding discs 12, 22.
After discharging the compressed air between them, the tail stock shaft 7 is disconnected from the main shaft 4, and is placed on standby to the left, before being removed.

In the above embodiment, the tire forming former is equipped with a belt forming drum on the left side of FIG. 3 instead of the left and right pair of belt rings 2, 2, and the belt and tread cap are stacked on this forming drum. The belt and tread cap may then be removed from the belt forming drum and transferred to an intermediate position between the bead holding discs 12, 22 by means of a belt transfer ring. Further, when the tire size is small, the tail stock shaft 7 can be omitted. Furthermore, the air supply system is not limited to the above embodiment; for example, the main shaft 4 of the above embodiment may be omitted, and the inner sleeve 8 of the above embodiment may be formed on the main shaft to provide a rotatable and slidable cantilever system. The free end of the hollow main shaft (inner sleeve 8) is sealed, and the free end of the air pipe 5 inserted into the main shaft is communicated between the left and right bead holding discs 12, 22. The internal space of the main shaft (inner sleeve 8) is
c, 20c.

As explained above, in this invention, when deforming a primary green tire into a toroidal shape, the left and right bead holding disks are brought closer together than before, so that the surface of the primary green tire is covered almost entirely on the inner surface of the belt. Since they can be brought into contact with each other, the uniformity of the product tire is improved, and the secondary molded green tire can be easily attached and detached.

[Brief explanation of the drawing]

1 and 2 are vertically cut front views of essential parts for explaining the operation of a conventional tire forming former, FIG. 3 is a vertically cut front view of an embodiment of the present invention, and FIG. FIG. 5 is a vertically cut front view of essential parts for explaining the operation of the above embodiment. G: Primary molded green tire, Ga: Bead part,
4: Main shaft, 10, 20: Support drum, 12, 2
2: Bead holding disc, 12a, 22a: Rim, 1
3, 23: Tubular diaphragm, 16, 2
6: bead retaining segment, 16a, 26a: rim.

Claims (1)

[Scope of Claims] 1. A tire molding former in which a pair of left and right bead holding discs each having a rim formed in a shape that follows the inner surface of a bead portion of a primary molded green tire is provided so as to be slidable in the axial direction. A support drum concentric with the main shaft is formed integrally with the bead holding disk axially outward of each of the bead holding disks, and an endless tubular diaphragm made of a rubber-like elastic body is attached to the outer surface of the support drum. A large number of bead holding segments each having a rim shaped to follow the outer surface of the bead portion of the primary molded green tire are arranged around the outer periphery of the tubular diaphragm in a ring shape so as to be freely slidable in the radial direction, As the tubular diaphragm expands and contracts, the bead retaining segment is slid in the radial direction such that at the outer end of its stroke, the diameter of the rim of the bead retaining segment matches the diameter of the rim of the bead retaining disk. A tire molding former characterized by: 2. The bead retaining segment is biased in a diameter-reducing direction by a spring, and the bead retaining segment is expanded in diameter by feeding compressed air into a tubular diaphragm against the elasticity of the spring. The tire molding former described in Scope 1. 3. A patent claim in which one bead holding disk is fixed to an inner sleeve that is slidable relative to the main shaft, and the other bead holding disk is fixed to an outer sleeve that is slidable relative to the inner sleeve. The tire molding former according to item 1 or 2.