JPH0153630B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The tire molding drum of the present invention is capable of performing full-step molding, but has a structure that forms a rigid cylindrical body similar to the primary molding drum of the two-step molding method, The aim is to improve and stabilize quality, as well as reduce man-hours, floor space, and equipment costs.

In the first place, radial tires have far superior maneuverability and durability compared to conventional bias tires, but on the other hand, extremely high precision is required in the uniformity of component parts in each manufacturing process. Ru. In particular, during the forming process, the concentricity of the bead wires, the ply cords and belts that form the frame of the tire, the symmetry of the arrangement of the treads that form the outer skin with respect to the tire center line, and the parallelism of the tire cords of each ply, etc. This has an extremely large impact on the quality of the product.

Therefore, high mechanical precision and rigidity are required for the tire molding machine and the molding drum in the molding process, so in order to avoid complicating the structure of the molding machine and the molding drum, the process is divided into two to avoid complicating the structure of the molding machine and molding drum. A high-quality cylindrical primary green tire with precise dimensions is formed on the rigid forming drum of the primary forming machine, and then transferred onto the forming former of the secondary forming machine, inflated into a toroidal shape, and the top surface A so-called 2-step molding method is used in which the belt and tread cap are attached to the belt.

According to this molding method, the functions of the primary molding machine and the secondary molding machine are divided and dedicated, which simplifies the structure and makes it easy to ensure rigidity and mechanical precision. Since it is molded on a rigid primary forming drum, a primary green tire with high molding accuracy can be obtained, and it has the advantage of easily ensuring good quality of the product tire. On the other hand, it is necessary to move the green tire from the primary molding machine to the forming former of the secondary molding machine, which increases the number of man-hours.
Further, when a primary molded green tire is transferred to a secondary molding machine, deformation may occur due to temporary storage or transportation, which may cause quality deterioration.

Furthermore, equipment costs are high because the molding machine is divided into a primary molding machine and a secondary molding machine, so the price per set is high, and a large floor space is required to store the molding machine and primary green tires. There was a drawback that it required Therefore, in order to eliminate the above drawbacks,
A cylindrical primary green tire is molded on a single molding drum, and then the primary green tire is transformed into a toroidal shape mechanically or by compressed air while bringing the left and right bead portions close to each other. The so-called full-step molding method, in which a belt and tread cap are attached to the top surface of the drum, has been adopted in some cases, but the structure of the molding drum is extremely complex, making it extremely difficult to maintain mechanical precision, and The cylindrical surface of the subsequent forming drum is discontinuous, and sometimes the cylindrical surface is a flexible elastic membrane, which makes it difficult to stabilize the quality of the first formed green tire.

Therefore, the tire molding drum of this application solves the above-mentioned drawbacks, and although it is a full-step molding method, it uses one of the two-step molding methods in the primary molding.
By providing a cylindrical body as rigid as the next forming drum, it is designed to improve and stabilize the quality of the product tire, reduce man-hours, reduce floor space, and reduce equipment costs. be.

Next, the structure of the tire forming drum of the present invention will be specifically described in detail based on the accompanying drawings.

FIG. 1 is a front sectional view showing an example of the implementation of the tire forming drum of this application, and the upper half of the figure shows the center drum at the center of the forming drum with its diameter expanded.
The bottom half of the figure shows a state in which the surfaces of the side rings and turn-up bladder provided on the left and right sides substantially form a single cylindrical surface and are ready for primary forming. The center drum reduces in diameter and moves to the right side, and fits inside the right side ring, and the left and right side rings, together with the turn-up bladder, approach each other symmetrically, and the bead wire corresponding part of the turn-up bladder expands in diameter While holding the bead part of the primary formed green tire, the inner diameter of the holding segment expands to form a truncated conical shape, and the green tire exhibits a preshaping state in which it is expanded into a toroidal shape. It is what it is.

FIG. 2 shows a side surface and a cross section of the center drum, with the upper half diagram showing the state when the diameter is reduced, and the lower half diagram showing the state when the diameter is expanded.

In FIG. 1, reference numeral 1 denotes the main shaft of a molding machine, into which a sleeve 2 having a bush 2a is fitted so as to be slidable and non-rotatable relative to each other.
are rotatably and slidably held at the right end in the headstock of a molding machine (not shown), and are rotated together by a drive means (not shown) and slid symmetrically with respect to each other. 3 is an inner cylinder fitted to the main shaft 1;
The left end is hermetically fitted into and fixed to a disc body 4 which is fitted with an annular bladder 5 and coupled with a sliding sleeve 6 which is slidably fitted to the main shaft 1 in an airtight manner. This disk body 4 rotates together with the main shaft 1 and slides with respect to the main shaft 1 by means of a key (not shown). Further, the flange portion on the outer periphery of this disc body 4 has a notch 4a in the circumferential direction.
A plurality of pairs of fan-like bodies, long and short, constituting the center drum 7, whose outer circumference forms a continuous circumference of a predetermined outer diameter when expanded, are fitted so as to be slidable in the radial direction.

This center drum 7 includes wide and narrow sliding pieces 8, 8' having sliding legs 8a and arc-shaped body segments 9.
That is, it consists of a long arc segment 9 and a short arc segment 9', and when the diameter is expanded, the sliding pieces 8, 8'
is pushed up by the top surface of the annular bladder 5, and the outer peripheries of the long arc-shaped body segment 9 and the short arc-shaped body segment 9' form a continuous circumference of a predetermined outer diameter,
When the diameter is reduced, the diameter is reduced by the contraction force of the annular coil spring 10, and as shown in FIG. It fits inside in the radial direction.

A stopper 11 is connected to the lower end of the sliding leg 8a of the sliding piece 8, and regulates the upper limit of the sliding piece 8, 8'. The downward limit of the sliding pieces 8, 8' when the diameter is reduced is limited by the step portions 8b on both sides of the sliding leg 8a coming into contact with the upper surface 4b of the flange portion of the disc body 4. 5a is a ventilation valve for the annular bladder 5 that is airtightly inserted into the valve hole 4c of the disc body 4.

12 is a connecting cylinder, which is airtightly connected to the sleeve 2 at a right end flange portion 12a, and an inner peripheral flange portion 12b.
A sliding sleeve 13 and an annular cylinder block 14 are connected to each other. A flange 15 that slides airtightly on the inner cylinder 3 is connected to the left end of the annular cylinder block 14, and an annular body 17 on which an annular bladder 16 is mounted on the right side of the flange 15.
However, the flange 15 and the annular cylinder block 14
are hermetically connected.

Reference numeral 18 denotes a plurality of segments provided in contact with the top surface of the annular bladder 16, and protrusions 18a are provided on both sides of the lower arc upper part, and each segment is connected to the annular body 17.
and the radial groove 15a of the flange 15, and slides along the groove in the radial direction.

A projecting edge 19a of a turn-up bladder 19 is fitted into a circumferential groove 18b provided in an upwardly extending portion of the plurality of segments 18.
The outer surface of this fitting portion strongly presses and holds the bead portion having the bead wire B of the green tire G to be molded from the inside during diameter expansion.

Reference numeral 20 denotes an annular coil spring that is attached around the circumference of the plurality of segments 18, and its contractile force brings the plurality of segments 18 into contact with the bottom surfaces of the radial grooves 17a and 15a provided in the annular body 17 and the flange 15. let

Reference numeral 21 denotes a stopper attached to the annular body 17, which together with the top surface of the radial groove 15a of the flange 15 regulates the upper limit of the ascent of the annular body 17. Reference numeral 16a designates a ventilation valve for the annular bladder 16 which is hermetically inserted into the valve hole 17b of the annular body 17.

22 is a side ring fitted and fixed to the outer periphery of the flanges 15, 15';
Attachment part 1 of turn-up bladder 19 between
9d, its outer diameter is substantially equal to the outer diameter of the center drum 7 when expanded, and the inner surface of the tip on the side facing the center drum 7 is tapered, At a position close to the center drum 7, it faces the tapered portion cut into the outer circumferential shoulders of the long and short arc-shaped body segments 9, 9' with a small gap therebetween. The inner circumferential surface of the small diameter portion on the left side of the annular cylinder block 14, together with the outer circumferential surface of the opposing sliding sleeve 13 and the flange 15, constitutes a first annular cylinder F having the inner cylinder 3 as a piston. Further, the inner circumferential surface of the right large diameter portion of the annular cylinder block 14, together with the left surface of the connecting cylinder 12 and the cover plate 23 connected to the annular cylinder block 14, is connected to a second piston 25 that accommodates the inner cylinder 24 on the right side. It constitutes an annular cylinder S.

26 is a plurality of support segments of the turn-up bladder 19, and arms 26a,
26b, and the arm 26a is pivotally connected to the other end of a link 27 that is pivotally connected to an ear 17c provided on the annular body 17. The other arm 26b is pivotally connected to the right end of the cylinder 24 coupled to the piston 25.

The ventilation valve 1 of the turn-up bladder 19 is located at the left end of a specific pair of opposing segments (may be only one segment) among the plurality of support segments 26.
9b and a valve hole 2 that accommodates the peripheral protrusion 19c.
6c and a counterbore hole 26h are provided, into which a ventilation valve 19b and a peripheral protrusion 19c are inserted.

An air supply hole 26d is provided at the right end of the pair of support segments 26, and the valve hole 26c and the air supply hole 26d are connected through a connection hole 26e. Also,
The air supply hole 26d is connected to a rotary joint (not shown) and communicates with a predetermined pressure fluid source through an elbow 26f, an air pipe 26g, an elbow 28a attached to a flange 28 fixed to the sleeve 2, and an air pipe 28b. .

The same mechanism as the above-mentioned mechanism is also provided on the left side of the center drum 7, but except for specially changed structural parts, the same number as the mechanism on the right side will be given and the explanation will be omitted.

Reference numeral 14' denotes an annular cylinder block, which is fitted onto the left end of the main shaft 1 and fixed with a nut 29 and a key 30. This annular cylinder block 14' has a third cylinder block with a cover plate 23 fixed to the left end.
It constitutes an annular cylinder R, and houses a piston 25 to which a cylinder 24 is connected at the left end.

Reference numerals 31 and 32 denote an outer air supply pipe and an inner air supply pipe inserted into the center hole 1a of the main shaft 1, and the right ends of both are hermetically connected to a rotary joint attached to the right end (not shown) of the main shaft. Both of their left ends are hermetically inserted into a cylinder 33 inserted and fixed to the left end of the main shaft 1.

The air supply outer pipe 31 has a through hole 31b in the axial direction.
A socket 31a whose outer surface is in airtight contact with the inner surface of the main shaft 1 is fitted and fixed airtightly as one body. Further, a radial through hole 31c is bored in the socket 31a.
The inner side communicates with the gap between the outer air pipe 31 and the inner air pipe 32, and the outer side communicates with the air gap 1 of the main shaft 1.
It communicates with c.

Further, a bush 34 is provided on the inner surface of the cylinder 33, which is airtightly inserted and fixed into the cylinder 33 and whose right end is closed. Its tip is hermetically fitted.

26'f is a union screwed into the air inlet of the support segment 26, which is connected to the union 33a screwed into the left end surface of the cylinder 33 through an air pipe 26'g, and is connected to the air inlet of the cylinder 33. 33b, 33
c, 33d, and 33e communicate the inner cavity of the turn-up bladder 19 and the air supply inner pipe 32. 33f
is a union different from the union 33a screwed into the cylinder 33, and is connected to the union 14'a screwed into the left end of the annular cylinder block 14' and the air pipe 1.
4'b, and vents 33g, 33h, 33i, 33j provided in the cylinder 33 and vents 14'c, 14'd provided in the annular cylinder block 14' allow the air supply outside of the main shaft 1 to be tube 3
1 and the air supply inner pipe 32 communicates with the third annular cylinder R.

In FIG. 1, B is a bead wire with a filler attached to it, which is waiting at a predetermined position with respect to the forming drum by a means not shown, and G is a bead wire that is strongly applied to the inner surface of the bead portion by the projecting edge 19a of the turn-up bladder 19. This is a section of a green tire that is being held in a secondary mold and pre-shaped into a toroidal shape.

Molding of a radial tire using the molding drum of the present invention described above is carried out as follows.

First, a driving means (not shown) is operated to symmetrically separate the main shaft 1 and the sleeve 2 to a predetermined distance from each other, and at the same time, the tail stock shaft T is extended to the right and is hermetically fitted into the bush 34 at the left end of the main shaft 1. At the same time, when a pressure fluid of a predetermined first pressure is fed into the gap between the air supply outer pipe 31 and the air supply inner pipe 32 from a rotary joint at the right end of the main shaft 1 (not shown), the pressure fluid introduced is , ventilation hole 31c of air supply outer pipe 31, main shaft 1
through the ventilation hole 1c, the main shaft 1 and the sliding sleeve 6,
It enters the gap between the inner cylinder 3 and the sliding bushing 13, passes through the ventilation hole 13a of the sliding bushing 13, and the first
It enters the right side of the annular cylinder F and pushes the inner cylinder 3 to the left so that the center drum 7 occupies the position shown in the upper half of FIG.

The pressure fluid at the first pressure simultaneously passes through the valve hole 4c of the disc body 4 and enters the inner cavity of the bladder 5, but since the force acting on the bladder 5 is weaker than the contraction force of the annular coil spring 10, the bladder 5 does not inflate. Further, the pressure fluid at the first pressure passes through the vent holes 14a, 14b of the annular cylinder block 14, enters the second annular cylinder S to the left, and presses the piston 25 to the rightmost position.

Also, in the left annular cylinder block 14', the pressure fluid at the first pressure is supplied to the main shaft 1.
Ventilation holes 33j, 33i, 33 of the cylinder 33 at the left end
h, 33g, union 33f, 14'a, vent hole 14'c, 14' of annular cylinder block 14'
d, it enters the third annular cylinder R to the right and presses the piston 25 to the leftmost position.

Next, the pressure fluid at the first pressure is switched to the pressure fluid at the second pressure, which is higher in pressure, and the bladder 5 is expanded against the contraction force of the annular coil spring 10 to expand the diameter of the arc-shaped body segment 9 and create a continuous A cylindrical surface with a predetermined outer diameter is formed. At this time, the pressures in the second annular cylinder S and the third annular cylinder R are simultaneously switched to the second pressure.

In this state, the center drum 7, side ring 22, and turn-up bladder 19 form an integral cylindrical shape, so the side wall, inner liner, and ply cord are arranged symmetrically around the center of the center drum around their outer periphery. Wrap it endlessly,
The left and right bead wires B are inserted into a holding means (not shown) concentrically with the axis of the forming drum, and are held in a predetermined position. Next, when a third pressure fluid is inserted into the gap between the center hole 1a of the main shaft 1 and the air supply outer pipe 31 from the rotation joint (not shown) at the right end of the main shaft 1, this third fluid flows through the ventilation hole 1b of the main shaft 1. , through the ventilation holes 2b, 2c of the sleeve 2 and the bush 2a, and further through the ventilation holes 14c, 14d, 14 of the sliding bush 13, the connecting cylinder 12, and the annular cylinder block 14.
e, 14f, enters the inner cavity of the annular bladder 16 through the valve 16a, inflates the annular bladder 16, and releases the inside of the bead wire B waiting on the outer surface of the protrusion 19a fitted into the segment 18 of the turn-up bladder 19. Hold it in place by applying strong pressure to the surrounding surface. At the same time, the supplied pressure fluid at the third pressure is separated from the vent hole 14d and flows through the vent hole 14g,
14h and 14i, it enters the second annular cylinder S to the right and acts on the right side of the piston 25. As mentioned above, the pressure fluid of the second pressure is acting on the left side of this piston 25, but the pressing effect of the third pressure fluid on the right side is smaller than the pressing effect of the pressure fluid, so the piston 25 is moved to the left side. Do not move in any direction.
Immediately after this, the bead wire holding means (not shown) disengages from the bead wire B and retreats to the standby position.

The fed pressure fluid at the third pressure enters the left side of the first annular cylinder through the gap between the annular body 17 and the annular cylinder block 14, and presses the inner cylinder 3 to the right. A pressure fluid of the second pressure is acting on the right side of the cylinder 3, and its pressing effect is greater, so the inner cylinder 3 does not move.

Also in the annular bladder 16 on the left side of the center drum 7 and in the third annular cylinder R, the pressure fluid at the third pressure sent into the socket 31
The ventilation holes 1d, 1 of the main shaft 1 pass through the horizontal hole 31b of a.
annular bladder 16 and piston 25 via e and 1f
It acts in the same way as above.

Next, pressurized fluid at a predetermined pressure is fed from the center hole Ta of the tail stock shaft T fitted into the left end of the main shaft 1 to fill the inner cavity of the green tire G through the bush 34, the cylinder 33, and the ventilation holes 34a, 33k, and 1e of the main shaft 1. At the same time, when the pressure fluid at the second pressure in the gap between the outer air pipe 31 and the inner air pipe 32 during air supply is switched to the fourth pressure fluid at a lower pressure, the center drum 7 resists the expansion force of the annular bladder 5 by the contraction force of the annular coil spring 10, and contracts in diameter to the shape shown in the upper half of FIG. At this point, the first
The fourth pressure fluid acts to the left of the inner cylinder 3 within the annular cylinder F and the inner cylinder 3 acts within the annular cylinder F'.
Since the pressing effect with the pressure fluid of the third pressure acting in the right direction is made such that the former is large or both are equal, the inner cylinder 3 does not move to the right and the center drum The diameter reduction of 7 is carried out without support.

Here, when the pressure fluid at the fourth pressure in the gap between the outer air pipe 31 and the inner air pipe 32 is removed to communicate with the atmosphere, the center drum 7 is moved together with the inner cylinder 3 in the lower half of FIG. Move to the position shown in the figure.

When the pressure fluid on the left side of the second annular cylinder S is exhausted, the piston 25 moves to the left due to the pressing effect of the third pressure fluid and rotates the link 27 counterclockwise, so that the support segment 26 teeth,
It becomes a truncated conical shape like the lower semicircle in Figure 1. The same phenomenon occurs in the annular bladder 16 and support segment 26 on the left side of the center drum 7.

Here, the pressure fluid at the third pressure mentioned above is increased to a fifth pressure to strengthen the holding of the bead wire B by the annular bladder 16, and at the same time, the main shaft 1 is moved to the right and the sleeve 2 is moved to the left by a driving means (not shown). When the bead parts having the left and right bead wires B of the green tire G on the forming drum are brought symmetrically close together, the ply cord between the beads on both sides expands into a toroidal shape and preshaping ( Preliminary shaping) is performed. Subsequently, pressure fluid at a predetermined pressure is fed into the air supply pipe 28b from a rotary joint (not shown), and the elbow 28a, the air supply pipe 26g, the elbow 26f, the air supply hole 26d, the communication hole 26e, and the ventilation valve 19h of the turn-up bladder 19 are closed. When the ply cord, inner liner, and sidewall that were endlessly wrapped around the outer surface of the green tire G of the bladder 19 are introduced into the inner cavity of the turn-up bladder 19 and inflated, the ply cord, inner liner, and sidewall that have been endlessly wound around the outer surface of the green tire G of the bladder 19 are turned into the turn-up bladder. While being stuck to the surface of the green tire 19, it expands in diameter together with the turn-up bladder 19 and stands up, and is strongly pressed and stuck to the side wall of the pre-shaped green tire G.

Further, the ply cord, inner liner, and sidewall are crimped to the side wall of the green tire G by the turn-up bladder 19 in some cases after the belt and tread cap are crimped to the side wall of the green tire G by the stitcher.

Immediately thereafter, the pressure fluid in the turn-up bladder lumen is removed, and the turn-up bladder 19 returns to its original shape. Regarding the turn-up bladder 19 on the left side of the center drum 7, air is supplied to the air supply inner pipe 32 from a rotary joint connected to the right end (not shown) of the main shaft 1, and air is supplied to the air supply inner pipe 32 through the ventilation holes 33e, 33d,
c, 33b, Unien 33a, air pipe 26'g,
Union 26'f of support segment 26, air supply hole 26d, communication hole 26e, turn-up bladder 1
A similar operation is performed using pressure fluid at a predetermined pressure that is introduced into the inner cavity of the turn-up bladder 19 through the ventilation valve 19b of 9.

When the above operation is completed, the transfer ring holding the preformed belt and tread cap (not shown) is transferred to a position aligned with the center line of the pre-shaped green tire G by a driving means (not shown). However, when the main shaft 1 and the sleeve 2 are slid symmetrically by a driving means (not shown) and the bead portion of the green tire G is further reduced to a predetermined distance, the diameter of the top surface of the green tire G is expanded, as shown in the figure. The center line is aligned correctly and brought into contact with the inner surface of the belt held by a transfer ring (not shown) to be crimped.

Next, the belt and tread cap of the transfer ring are released from the belt and tread cap by means not shown, and the transfer ring is moved to the standby position.

Next, the pressure fluid filling the inner cavity of the green tire G from the center hole Ta of the tail stock shaft T is increased to a predetermined pressure to increase the membrane force of the green tire G, and then the belt is tightened by a stitcher (not shown). Completely crimp the tread cap and the ply cord turned up earlier.

This completes the molding. Therefore, the pressurized fluid in the inner cavity of the green tire G is removed through the reverse route to the above-mentioned feeding time, and then the air supply outer pipe 31 and the air supply inner pipe 3 are removed.
Pressure fluid is supplied from the same pressure source as the fourth pressure into the gap between the main shaft center hole 1a and the air supply outer pipe 31, and the pressure fluid at the fifth pressure is supplied to the gap between the main shaft center hole 1a and the air supply outer pipe 31 at a predetermined pressure. When the pressure is reduced to 6, the second and third
The pressing force on the inside of the annular cylinder piston 25 with respect to the center line of the forming drum is greater, and both the pistons 25 move outward, and the left and right support segments 26 return to the horizontal position.

At the same time, the pressure fluid in the gap between the main shaft center hole 1a and the outer air pipe 31 and the pressure fluid in the gap between the outer air pipe 31 and the inner air pipe 32 are removed to contract the annular bladder 16. turn up bladder 19
and the bead part of the green tire G,
A green tire G whose molding is completed by retracting the tail stock shaft T to the left by a drive means (not shown)
Pull it out from the top of the forming drum to the left.

In addition, in the above-mentioned embodiment, several types of operations are performed using the same feeding/discharging system in various operations of the forming drum by feeding each pressure fluid, but of course,
It may be a separate system, or it may be a mechanism such as a screw or rack and pinion instead of using pressure fluid.

As mentioned above, in the forming drum of the present invention, the center drum constitutes a rigid cylindrical surface with a continuous surface when the diameter is expanded, and primary forming is performed on the complete cylindrical surface together with the side rings on both sides. As a result, the quality of the tire being molded is significantly improved compared to the conventional full-step molding drum, which produces gaps between segments during diameter expansion.

Furthermore, compared to 2-step molding, the quality of the first-formed green tire does not change, and secondary molding is performed on the same molding drum, which has the effect of making the quality of the finished tire more stable. be. In addition, the equipment cost is lower than that of a 2-step molding machine, which consists of two machines in one set.Furthermore, it occupies much less valuable factory floor space, and has high labor productivity. It is something.

[Brief explanation of drawings]

FIG. 1 is a front sectional view showing an example of the implementation of the tire forming drum of the present invention. FIG. 2 is a side view and a sectional view of the center drum section when the upper bladder section is in a truncated conical shape. 7... Center drum, 9 ... Arc-shaped body segment (long arc-shaped body segment and short arc-shaped body segment),
9...Long arc body segment, 9'...Short arc body segment, 19...Turn-up bladder, 22
...Side ring.

Claims (1)

[Claims] 1. A center drum whose diameter can be freely expanded or contracted, and a pair of sides arranged concentrically on both sides thereof, whose outer diameter is the same as the outer diameter of the center drum when the diameter is expanded, and which can slide symmetrically to each other in the axial direction. In a forming drum for a radial tire, the forming drum for a radial tire includes a ring and a pair of left and right turn-up bladders provided on the axially outer side of the side ring and having an outer diameter when contracted that is substantially equal to the outer diameter of the side ring. The drum is divided into pairs of long and short arc segments, and when expanding, the surface of each pair of arc segments forms a continuous cylindrical surface, and when contracting, the short arc segments form a continuous cylindrical surface. , a tire forming drum characterized by having a structure that fits inside the long arc-shaped body segment in the radial direction.