JP2003146027A - Bead core intermediate, and manufacturing method of and device for the same - Google Patents

Abstract

PROBLEM TO BE SOLVED: To improve tire quality by suppressing adhesive failure, air intrusion and the like in a bead core 33. SOLUTION: A bead core intermediate 21 comprising one spirally wound bead cord 22 is displaced axially outward of a radial straight line L in the region of at least a part (the whole in this mode) between a winding start position and a winding end position, so that the sectional form of the bead core intermediate 21 is substantially the same as a final sectional form thereof in a pneumatic tire 25 to thus practically prevent deformation of the bead core intermediate 21 until an end of vulcanization after its attachment to tire component members.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a bead core intermediate body formed by spirally winding one bead cord, and a method and an apparatus for producing the bead core intermediate body.

[0002]

2. Description of the Related Art In recent years, in order to improve the efficiency and simplification of pneumatic tire manufacturing work and to improve the performance thereof, for example, a method described in Japanese Patent Laid-Open No. 11-115420 has been proposed. Has been done.

In this product, first, a belt-shaped unvulcanized rubber is spirally or spirally attached to the outer side of a rigid core whose outer surface has the same shape as the inner surface of a pneumatic tire to form an inner liner. The inner bead core is attached to the outer side of the bead portion of the inner liner, and then the rubber-coated carcass cord is attached to the outer side of the inner liner in the meridian direction while being folded back at both bead portions, while shifting such attachment in the circumferential direction. The carcass layer is formed by performing the process a number of times.

Next, an outer bead core is attached to the outside of the bead portion of the carcass layer, and then a ribbon-shaped body having a small number of belt cords coated with rubber is spirally wound many times on the outside of the tread portion of the carcass layer. After forming layers, these belt layers, carcass layers, and belt-shaped unvulcanized rubber are attached to the outside of the outer bead layer in a spiral or spiral shape to form top treads and side treads to produce unvulcanized tires. Then, the unvulcanized tire is then vulcanized to obtain a pneumatic tire.

Here, the above-mentioned inner and outer bead cores constituting the bead core are manufactured by a bead core manufacturing apparatus in advance by an external setup, and then conveyed to the above-mentioned position and attached. For manufacturing, for example, as shown in FIG. 18, first, a pair of molded bodies 11, 12 of a bead core manufacturing apparatus are brought close to each other and combined, and a width W between the molded bodies 11, 12 is a bead cord.
An annular groove 14 is formed which is substantially equal to the diameter of one of 13 and which extends in the radial direction and has a rectangular sectional shape.

Thereafter, the above-mentioned combined molded bodies 11 and 12 are combined.
By supplying one bead cord 13 into the annular groove 14 while integrally rotating the bead cord 13, the bead cord 13 is precisely spirally wound outward in the annular groove 14 in the annular groove 14 to form a straight line in the radial direction. After manufacturing a flat hollow disk-shaped bead core intermediate body 15 extending along, and then separating the molded bodies 11 and 12 from each other, the bead core intermediate body 15
The molded bodies 11 and 12 were taken out and conveyed to the bead portion so that one piece or a plurality of pieces were stuck while being stacked in the axial direction.

[0007]

However, since the cross-sectional shape of the bead core intermediate body 15 manufactured as described above is different from the bead core cross-sectional shape (final cross-sectional shape) of the product tire, the bead core intermediate body 15 is From the time of application to the time of completion of vulcanization, it will be deformed to the final cross-sectional shape due to the flow of rubber, etc., which will result in poor adhesion of the bead core, air inclusions around the bead core, etc.
There is a problem that tire quality may deteriorate.

An object of the present invention is to provide a bead core intermediate body capable of improving tire quality by suppressing adhesion failure, air entrapment, etc., and a method and an apparatus for producing the bead core intermediate body.

[0009]

[Means for Solving the Problems]
A bead core intermediate body, which is formed by spirally winding one bead cord outward in the radial direction, and is a bead core of a pneumatic tire by being superposed in the axial direction. By displacing at least a part of the bead cord from the start position to the winding end position in the axial direction with respect to the radial straight line,
With a bead core intermediate body whose cross-sectional shape is substantially the same as the final cross-sectional shape in the pneumatic tire,

Secondly, a pair of molded bodies are assembled close to each other, and the width between these molded bodies is substantially equal to one bead cord, and the cross-sectional shape of the bead cord in the pneumatic tire is the same. A step of forming an annular groove at least a portion of which is axially displaced with respect to a radial straight line so as to have a shape substantially the same as the final cross-sectional shape; and 1 in the annular groove while integrally rotating the combined molded body. A step of forming a bead core intermediate body by spirally winding the bead cord outward in a radial direction in an annular groove by supplying a bead cord of a book; and after separating the formed body from each other, a bead core intermediate body By the method for producing a bead core intermediate including a step of removing the body from these molded bodies,

Thirdly, by combining a pair of molded products and these molded products in close proximity to each other, the width between these molded products is substantially equal to one bead cord, and the cross-sectional shape thereof is air. A contacting / separating means for forming an annular groove, at least a part of which is axially displaced with respect to a radial straight line, so as to have substantially the same shape as the final cross-sectional shape of the bead cord in the filled tire; By supplying one bead cord into the annular groove of the rotating molded body and a rotating means for integrally rotating the bead cord, the bead cord is spirally wound outward in the annular groove in a radial direction. And a feeding means for molding the intermediate body, and after molding the bead core intermediate body, the molding bodies are separated from each other by the contacting and separating means, and the bead core intermediate body is taken from these molding bodies. It can be achieved by the manufacturing apparatus of the bead core intermediates as issued.

In the invention according to claim 1, the bead core intermediate body constituting the bead core is formed by spirally winding one bead cord outward in the radial direction, and winding the bead cord from the winding start position. By displacing at least a part of the bead core reaching the stacking end position in the axial direction with respect to the radial straight line, the cross-sectional shape of the bead core intermediate body is made substantially the same as the final cross-sectional shape in the pneumatic tire. Therefore, after being attached to the outside of the bead portion of the carcass layer, the bead core intermediate body is hardly deformed until the end of vulcanization, and as a result, poor adhesion of the bead core, air entry around the bead core, etc. are suppressed, and the tire Quality is improved. Then, such a bead core intermediate can be easily manufactured with high efficiency and high accuracy by the manufacturing method according to claim 4 and the manufacturing apparatus according to claim 5.

The bead core intermediate body described above is suitable for manufacturing a pneumatic tire as set forth in claim 2. Further, according to the third aspect, it is possible to strongly suppress the above-mentioned adhesion failure and air entry. Further, according to the sixth aspect, when the molded body is supported on the same rotating shaft for the purpose of simplifying the structure and downsizing, the work of taking out the molded bead core intermediate body is facilitated.

[0014]

BEST MODE FOR CARRYING OUT THE INVENTION A first embodiment of the present invention will be described below with reference to the drawings. In FIG. 1, 21 is a bead cord 22, for example, a bead core intermediate body formed by spirally winding steel wire having a circular cross section from the inner side in the radial direction to the outer side in the radial direction. The bead core intermediate 21 is composed of a bead code 22 having only one line.

The bead core intermediate body 21 is a bead cord extending from a winding start position (starting end of the bead cord 22 located at the inner end in the radial direction) to a winding end position (end end of the bead cord 22 located at the outer end in the radial direction). At least a part of 22 and here all the bead cords 22 are connected to the radial straight line L.
On the other hand, it is displaced in the axial direction (in FIG. 1, gradually outward in the tire axial direction as it goes outward in the radial direction). Then, due to such axial displacement of the bead cord 22, the cross-sectional shape of the bead core intermediate body 21 becomes substantially the same as the final cross-sectional shape in the pneumatic tire (product tire) in which the bead core intermediate body 21 is mounted. Molded.

2 and 3 are drawings for explaining an example of a process of molding a pneumatic tire 25 using the bead core intermediate body 21 described above. In the figure, 26 is a rigid core made of metal having a donut shape as a whole, and the outer surface of the rigid core 26 has the same shape as the inner surface of the vulcanized pneumatic tire 25 (product tire). . The bead core intermediate body 21 described above is suitable for manufacturing a pneumatic tire 25 using such a rigid core 26.

Reference numeral 28 denotes an unvulcanized tire formed on the outside of the rigid core 26. The unvulcanized tire 28 includes, for example, the unvulcanized tire constituent member and the bead core intermediate body 21 according to the following steps. It is molded by sticking it to the outside of the rigid core 26 one after another. That is, first, an unvulcanized rubber ribbon is spirally and spirally wound around the rigid core 26 multiple times to form an inner liner 29 which is a part of a tire constituent member, and then the outer side of the inner liner 29 at the bead portion B is formed. Attach the bead core intermediate body 21 to the inside bead core
Set to 30.

Next, a carcass cord coated with unvulcanized rubber is wrapped around the outer side of the inner liner 29 in the meridian direction while being folded back at both bead portions B, and such winding is shifted many times while shifting in the circumferential direction. Then, the carcass layer 31, which is a part of the tire constituent member, is formed. After that, the above-mentioned bead core intermediate body 21, here, two bead core intermediate bodies 21 having different numbers of windings are attached to the outside of the carcass layer 31 in the bead portion B while closely adhering in the axial direction to form the outer bead core 32.

As a result, the carcass layer 31 in the bead portion B has the inner bead core 30 and the outer bead core 32.
Will be pinched from both sides and moored. In this way, the bead core intermediate bodies 21 (inner and outer bead cores 30 and 32) in which a plurality of the carcass layers 31 in the bead portion B are sandwiched in the axial direction, in this case, only three, in this case, the bead cores 33 are arranged as a whole. Constitute.

Next, the carcass layer 31 in the tread portion T
A small number of parallel belt cords coated with unvulcanized rubber are spirally wound on the outer side in the radial direction a number of times in a spiral, or a number of times are applied while shifting in the circumferential direction while tilting with respect to the equatorial plane. As a result, the belt layer 35 that is a part of the tire constituent member is formed.

Then, a large number of unvulcanized rubber ribbons are spirally wound around the outer side of the carcass layer 31 in the side wall portion S in a spiral shape to form a side tread 36 which is a part of a tire constituent member, and in the tread portion T. Carcass layer
An unvulcanized rubber ribbon is spirally wound a number of times on the outer side in the radial direction of 31 to form a top tread 37 which is a part of a tire constituent member to obtain an unvulcanized tire 28. After that, after conveying the unvulcanized tire 28 and the rigid core 26 to the vulcanizing device,
Unvulcanized tire 28 is vulcanized by the vulcanizing apparatus to obtain pneumatic tire 25.

Since the carcass layer 31 in the bead portion B of the vulcanized pneumatic tire 25 (product tire) is inclined outward in the axial direction as it goes outward in the radial direction as shown in FIG. The final cross-sectional shape of the bead core 33 that is in close contact with the carcass layer 31, that is, the entire inner and outer bead cores 30 and 32 in the pneumatic tire 25 is also inclined like the carcass layer 31.

However, as described above, these insides,
After molding the bead core intermediate body 21 to be the outer bead cores 30 and 32 into a shape that is substantially the same as the final cross-sectional shape, it is attached to the outer side of the rigid core 26 together with the tire constituent member and the unvulcanized tire 28.
The bead portion B of the carcass layer 31 is formed by molding
The bead core intermediate body 21 (inner and outer bead cores 30 and 32) hardly deforms after being attached to the outer side of the bead after vulcanization. As a result, poor adhesion of the bead core 33 and air entering around the bead core 33. Etc. are suppressed, and tire quality is improved. At this time, if the cross-sectional shape of the bead core intermediate body 21 is a truncated cone shape that is displaced outward in the axial direction of the pneumatic tire 25 as it goes outward in the radial direction as described above,
It is possible to strongly suppress the above-mentioned adhesion failure and air entry.

Here, the bead core intermediate as described above
21 can be easily manufactured with high efficiency and high accuracy by using a manufacturing apparatus 38 as shown in FIGS. In the figure, 39 is a horizontal rotary shaft, and a drive unit (not shown) for applying a rotary driving force to the rotary shaft 39 is installed on one side of the rotary shaft 39. A fixed plate 40, which is in the form of a disk and is coaxial with the rotary shaft 39, is fixed to the outside of the rotary shaft 39.
A plurality of slits 41 extending in the radial direction and equiangularly spaced in the circumferential direction are formed in the.

On the other side of the fixed plate 40, a pair of guide rails 42 extending along the slits 41 is laid on both sides of each slit 41, and each pair of guide rails is laid.
A fan-shaped forming segment 43 is supported by 42 so as to be movable in the radial direction. As a result, the plurality of molding segments 43 are arranged apart from each other in the circumferential direction and are supported by the fixed plate 40 so as to be movable in the radial direction. Then, the plurality of molded segments 43 collectively constitute one molded body 44.

A slider 45 is axially movably fitted to the outside of the rotary shaft 39 on one side of the fixed plate 40, and the slider 45 is rotated by an axially extending key 46 fixed to the rotary shaft 39. It is connected to the shaft 39 so as to rotate integrally therewith. 47 is a plurality of connecting links that are inclined to the other side as they go outward in the radial direction, and these connecting links 47 are arranged at equal angular intervals in the circumferential direction, and their radial outside portions are inserted into the slits 41. There is. Further, the radial outer ends of these connecting links 47 have the corresponding formed segments 43.
The inner end in the radial direction is rotatably connected to the slider 45.

Reference numeral 48 denotes a fixed frame installed on one side of the fixed plate 40, and a plurality of cylinders 49 extending parallel to the rotary shaft 39 are attached to the fixed frame 48 at equal angular intervals in the circumferential direction. Pislon rod of these cylinders 49
The tip end portion of 50 and the slider 45 are connected to each other via a bearing 51 interposed therebetween, and as a result,
When the cylinder 49 operates synchronously and the pithron rod 50 projects, the slider 45 moves to the other side in the axial direction and the connecting link 47 swings to the upright side, so that the molding segment 43 is guided by the guide rail 42 and radially outward. And the molded body 44 expands in diameter.

On the other hand, when the pithron rod 50 retracts due to the synchronous operation of the cylinder 49, the slider 45 moves to one side in the axial direction and the connecting link 47 swings to the falling side, so that the molding segment 43 is guided by the guide rail 42. While moving inward in the radial direction, the compact 44 is reduced in diameter.

A movable base 55 is fitted to the outside of the rotary shaft 39 on the other side of the fixed plate 40 so as to be movable in the axial direction, and the movable base 55 is fixed by the key 56 fixed to the rotary shaft 39 and extending in the axial direction. It is connected so as to rotate integrally with the rotating shaft 39. Reference numeral 58 denotes a pair of guide rails laid on one side surface of the movable table 55. The guide rails 58 are arranged so as to face the guide rails 42, extend in the radial direction, and extend in the circumferential direction. Angled apart.

A fan-shaped forming segment 60 is supported on the pair of guide rails 58 so as to be movable in the radial direction. As a result, the plurality of molding segments 60 are arranged apart from each other in the circumferential direction and are supported by the movable base 55 so as to be movable in the radial direction. And
The plurality of molded segments 60 collectively constitute the other molded body 61. From this, a pair of molded bodies 44,
61 is supported by the same rotary shaft 39 so as to be able to rotate integrally.

Reference numeral 64 denotes a plurality of guide rods having the other ends fixed to the respective molding segments 60 and extending parallel to the rotary shaft 39,
One side of these guide rods 64 is
Slidably inserted into the fixed plate 40 and inserted into a slit 65 extending parallel to the guide rail 42. As a result, the molded segment 60 (molded body 6
1) is supported by the rotating shaft 39 so as to be movable in the axial direction while maintaining a one-to-one correspondence with the molding segment 43 (molding body 44), whereby the molding segment 60 (molding body 61) and molding The segment 43 (molded body 44) can be spaced apart from each other. Also, these molding segments 60
The (molded body 61) and the molded segment 43 (molded body 44) can be moved in synchronization in the radial direction by the guide rod 64.

Reference numeral 67 is a flange formed at the tip (other end) of the rotary shaft 39. Between the flange 67 and the movable base 55, a biasing force for biasing the movable base 55 toward one side is provided. A spring 68 as a means is interposed. When the movable base 55 and the molded body 61 are moved to one side while being guided by the key 56 by the urging force of the spring 68, the molded body 61 is
Approaching 44, they combine with each other. Reference numeral 70 denotes a plurality of cylinders to which the fixed frame 48 is attached. A guide rod 64 is provided at the tip of a piston rod 71 of these cylinders 70.
A pressing ring 72 capable of contacting one end surface of is fixed.

When the piston rods 71 project synchronously by the operation of these cylinders 70, the pressing ring 72 comes into contact with the guide rod 64, and the guide rod 64 and the molded body 6
1. The movable base 55 is moved to the other side against the spring 68 to separate the molded body 61 from the molded body 44. The guide rod 64, the spring 68, the cylinder 70, and the pressing ring 72 described above.
As a whole, the contacting / separating means 73 for bringing the molded bodies 44, 61 into close contact with each other or combining them, or for separating them from each other.
Make up.

Further, the rotating shaft 39 and the driving unit described above constitute a rotating means 74 for integrally rotating the combined molded bodies 44 and 61 as a whole, and further, the guide rail 4 described above.
2, 58, slider 45, connecting link 47, cylinder 49, bearing 5
1. The guide rod 64 constitutes expansion / contraction means 75 for expanding / contracting the moldings 44, 61 by moving the molding segments 43, 60 constituting the moldings 44, 61 as a whole in the radial direction in synchronization with each other.

As described above, in order to make the structure of the entire apparatus simple and downsized, when the pair of molded bodies 44 and 61 are supported by the same rotary shaft 39 so as to be integrally rotatable, the molded bodies 44 and 61 are It is composed of a plurality of molding segments 43, 60 respectively spaced apart in the circumferential direction, and by expanding and contracting the moldings 44, 61 by moving the molding segments 43, 60 in the radial direction by the expansion / contraction means 75. By doing so, it is easy to take out the bead core intermediate body 21 that has already been formed.

Here, the other side surface of each of the molding segments 43 described above is a vertical surface 43a whose inner side in the radial direction extends parallel to the straight line in the radial direction, but its outer side in the radial direction goes toward the outer side in the radial direction. The inclined surface 43b is inclined to the other side. On the other hand, one side surface of each molding segment 60 also has a vertical surface 60 whose inner end in the radial direction extends parallel to the radial straight line.
Although it is a, the outer side in the radial direction becomes an inclined surface 60b inclined toward the other side toward the outer side in the radial direction at the same angle as the inclined surface 43b.

Since the boundary line between the vertical surface 43a and the inclined surface 43b is located slightly outward in the radial direction from the boundary line between the vertical surface 60a and the inclined surface 60b, the vertical surface 43a and the vertical surface 60b.
When the molded bodies 44, 61 are combined by abutting with a, an annular groove 77 is formed between these molded bodies 44, 61, more specifically between the inclined surface 43b and the inclined surface 60b.

The width W of the above-mentioned annular groove 77 corresponds to one bead cord 22 described above, that is, one bead cord 22.
It is substantially equal to the diameter of 22. In addition, the inclined surface 43b described above,
The inclination angle A of 60b with respect to the radial straight line L is
The bead cord 22 in the pneumatic tire 25 has a cross-sectional shape of 77.
The angle is set to be substantially the same as the final cross-sectional shape of the circular groove 77. As a result, in this embodiment, the entire annular groove 77 is inclined with respect to the radial straight line L and is displaced outward in the axial direction.

Reference numeral 79 is a reel installed away from the molded bodies 44 and 61, and one bead cord 22 is wound around the reel 79 a number of times. Then, the bead cord 22 unwound from the reel 79 is supplied into the annular grooves 77 of the molded bodies 44 and 61 while being guided by the plurality of guide rollers 80. The reel 79 and the guide roller 80 described above as a whole supply one bead cord 22 into the annular groove 77 of the rotating molded bodies 44 and 61, whereby the bead cord 22
A supply means (81) for forming the bead core intermediate body (21) is wound in a spiral shape in the annular groove (77) toward the outside in the radial direction.

Next, when the bead core intermediate body 21 is manufactured by using the above-mentioned manufacturing apparatus 38, one bead cord 22 is unwound from the reel 79 and its starting end is transferred to the vicinity of the manufacturing apparatus 38. . At this time, the molded body 61 has the spring 68.
By the urging force of, the molded bodies 44 are brought close to each other and combined with each other, and an annular groove 77 is formed between them. Further, at this time, since the pithron rod 50 of the cylinder 49 is projecting, the molding segments 43, 60 and the guide rod 64 move radially outward while being guided by the guide rails 42, 58, and the moldings 44, 61 expand in diameter. Located in a state.

Next, the driving force is applied to the rotary shaft 39 by the driving unit to integrally rotate the fixed plate 40, the movable base 55, and the molded bodies 44 and 61, and the starting end portion of the bead cord 22 is molded. Supply in the annular groove 77 between the bodies 44, 61. At this time,
Since the deepest portion of the annular groove 77 is gradually narrowed, the starting end portion of the bead cord 22 is sandwiched from both sides by the deepest portion of the annular groove 77 and locked to the molded bodies 44 and 61.

As a result, the bead cord 22 is spirally wound outward in the radial direction in the annular groove 77 while being taken up by the rotating molded bodies 44 and 61. During such winding, a predetermined braking force is applied to the reel 79 on which the bead cord 22 is unwound to generate a certain tension in the bead cord 22, and the bead cords 22 that have been wound are brought into close contact with each other. Let

Here, since the annular groove 77 has a cross-sectional shape that is substantially the same as the final cross-sectional shape of the bead cord 22 in the pneumatic tire 25 as described above, the bead cord
The bead core intermediate body 21 formed by winding 22 is also
The cross-sectional shape is almost the same as the final cross-sectional shape in the pneumatic tire 25. Then, when the bead cord 22 is wound a predetermined number of times to manufacture the bead core intermediate body 21,
After stopping the rotation of the rotary shaft 39 and the molded bodies 44 and 61, the bead cord 22 is cut at the cutting position, and the completed bead core intermediate body 21 is separated from the bead cord 22.

Next, after the bead core intermediate body 21 is gripped from the outside in the radial direction by a conveying means (not shown), the piston rod 71 of the cylinder 70 is projected to push the guide rod 64 back against the spring 68 against the other side. This allows
The molded body 61 moves to the other side while being guided by the key 56 together with the movable base 55 and separates from the molded body 44.
To the transport means.

Next, the pithron rod 50 of the cylinder 49 is retracted and the connecting link 47 is swung to form the molded segment 4.
3, 60 and the guide rod 64 are integrally moved along the guide rails 42 and 58 inward in the radial direction. When the diameters of the molded bodies 44 and 61 are reduced until the outer diameter thereof becomes smaller than the inner diameter of the bead core intermediate body 21, the operation of the cylinder 49 is stopped.

After that, the bead core intermediate body 21 is taken out from the molded bodies 44 and 61 by the above-mentioned conveying means, and then the rigid core 26
The inner liner 29 and the carcass layer 31 are attached to the outside of the bead portion B. At this time, the pithron rod 50 of the cylinder 49 is projected to expand the diameters of the molded bodies 44 and 61, and the piston rod 71 of the cylinder 70 is retracted to bring the molded body 61 closer to the molded body 44 by the urging force of the spring 68 to combine them. An annular groove 77 is formed between the formed bodies 44 and 61.

7 and 8 are views showing a second embodiment of the present invention. In this embodiment, as shown in FIG. 7, the final shape of the bead core intermediate body 21 and the carcass layer 31 between these bead core intermediate bodies 21 in the pneumatic tire 25 is parallel to the radial straight line at the radially outer portion. The radial inner portion is gradually displaced outward in the axial direction toward the outer side in the radial direction. In such a case, as shown in FIG. 8, the sectional shape of the annular groove 77 formed between the molded bodies 44 and 61 is made substantially the same as the sectional shape of the bead core intermediate body 21. The cross-sectional shape of the bead core intermediate body 21 molded by 77 is made substantially the same as the final cross-sectional shape in the pneumatic tire 25.

9 and 10 are views showing a third embodiment of the present invention. In this embodiment, as shown in FIG. 9, the final shape of the bead core intermediate body 21 in the pneumatic tire 25 and the carcass layer 31 between these bead core intermediate bodies 21 is directed radially outward at the radially outer portion. Accordingly, it is gradually displaced outward in the axial direction, while on the inner side in the radial direction, it extends parallel to the straight line in the radial direction. In such cases,
As shown in FIG. 10, the cross-sectional shape of the annular groove 77 formed between the molded bodies 44 and 61 is substantially the same as the cross-sectional shape of the bead core intermediate body 21.

11 and 12 are views showing a fourth embodiment of the present invention. In this embodiment, as shown in FIG. 11, the final shape of the bead core intermediate body 21 and the carcass layer 31 between these bead core intermediate bodies 21 in the pneumatic tire 25 is the outer end in the radial direction and the inner end in the radial direction. Both of the parts gradually displace outward in the axial direction as they go outward in the radial direction, while at the central part in the radial direction, they extend parallel to the straight line in the radial direction. In such a case, as shown in FIG.
The sectional shape of the annular groove 77 formed between the molded bodies 44, 61 is substantially the same as the sectional shape of the bead core intermediate body 21.

13 and 14 are views showing a fifth embodiment of the present invention. In this embodiment, as shown in FIG. 13, the final shape of the bead core intermediate body 21 and the carcass layer 31 between these bead core intermediate bodies 21 in the pneumatic tire 25 is the outer end in the radial direction and the inner end in the radial direction. Both of the portions extend parallel to the straight line in the radial direction, while the central portion in the radial direction is gradually displaced outward in the radial direction toward the outer side in the radial direction. In such a case, as shown in FIG. 14, the sectional shape of the annular groove 77 formed between the molded bodies 44 and 61 is made substantially the same as the sectional shape of the bead core intermediate body 21.

FIG. 15 is a diagram showing a sixth embodiment of the present invention. In this embodiment, the cross-sectional shape of the annular groove 77 formed between the molded bodies 44 and 61 is gradually displaced inward in the axial direction as it goes outward in the radial direction at the radially outer side, and at the radially inner side in the radial direction. The bead core intermediate body 21 having a dogleg-shaped cross section is formed by gradually displacing the bead core toward the outer side in the axial direction toward the outer side in the direction.

FIG. 16 is a diagram showing a seventh embodiment of the present invention. In this embodiment, the cross-sectional shape of the annular groove 77 formed between the molded bodies 44 and 61 is gradually displaced outward in the radial direction at the radially outer portion, and is radially displaced at the radially inner portion. It is gradually displaced inward in the axial direction toward the outer side in the direction, whereby the bead core intermediate body 21 having an inverted cross section is formed.

FIG. 17 is a diagram showing an eighth embodiment of the present invention. In this embodiment, the cross-sectional shape of the annular groove 77 formed between the molded bodies 44 and 61 is gradually displaced inward in the axial direction as it goes outward in the radial direction at the radially outer side, and at the radially inner side in the radial direction. The bead core intermediate body 21 having the same cross-sectional shape as the cross-sectional shape of the annular groove 77 is formed.

In the above-described embodiment, when the unvulcanized tire 28 is manufactured by the rigid core 26, the bead core 33 is formed by using the bead core intermediate body 21. When manufacturing an unvulcanized tire with a tire-shaped tire molding drum, the bead core may be molded by stacking a plurality of the above-mentioned bead core intermediate bodies while closely adhering to each other in the axial direction.

Further, in the above-mentioned embodiment, the case where the molded bodies 44 and 61 are supported by the same rotary shaft 39 so as to be able to integrally rotate has been described, but in the present invention, a pair of coaxial rotary shafts. The molded bodies may be supported so as to rotate integrally with each other, and when these rotating shafts are brought close to each other and coupled, the molded bodies may be combined with each other to form an annular groove. In this case, the molded bead core intermediate body can be taken out from between the rotary shaft and the molded body only by separating the rotary shafts from each other.

Further, in the above-described embodiment, only the molded body 61 of the molded bodies 44 and 61 is supported by the rotating shaft 39 so as to be movable in the axial direction, but in the present invention, the molded body 44 is used.
Only the rotating shaft 39 may be supported so as to be movable in the axial direction, or both the molded bodies 44 and 61 may be supported by the rotating shaft 39.
You may make it support so that it can move in the axial direction.

[0057]

As described above, according to the present invention, it is possible to improve the tire quality by suppressing the adhesion failure in the bead core, the entry of air and the like.

[Brief description of drawings]

FIG. 1 is a partially cutaway side view of a bead core intermediate body showing a first embodiment of the present invention.

FIG. 2 is a meridional sectional view of an unvulcanized tire using a rigid core and a bead core intermediate.

FIG. 3 is a meridional sectional view in the vicinity of a bead portion of a vulcanized pneumatic tire.

FIG. 4 is a side sectional view showing an example of a manufacturing apparatus for manufacturing a bead core intermediate body.

5 is a cross-sectional view taken along the line II of FIG.

FIG. 6 is a side sectional view in the vicinity of a molded body and a bead core intermediate body.

FIG. 7 is a meridional sectional view near a bead portion of a pneumatic tire showing a second embodiment of the present invention.

FIG. 8 is a side sectional view in the vicinity of a molded body and a bead core intermediate body used in the second embodiment.

FIG. 9 is a meridional sectional view near a bead portion of a pneumatic tire showing a third embodiment of the present invention.

FIG. 10 is a side sectional view in the vicinity of a molded body and a bead core intermediate body used in the third embodiment.

FIG. 11 is a meridional sectional view in the vicinity of a bead portion of a pneumatic tire showing a fourth embodiment of the present invention.

FIG. 12 is a side sectional view in the vicinity of a molded body and a bead core intermediate body used in the fourth embodiment.

FIG. 13 is a meridional sectional view near a bead portion of a pneumatic tire showing a fifth embodiment of the present invention.

FIG. 14 is a side sectional view in the vicinity of a molded body and a bead core intermediate body used in the fifth embodiment.

FIG. 15 is a side sectional view of a molded body and a bead core intermediate body according to a sixth embodiment of the present invention.

FIG. 16 is a side sectional view in the vicinity of a molded body and a bead core intermediate body showing a seventh embodiment of the present invention.

FIG. 17 is a side sectional view of a molded body and a bead core intermediate body according to an eighth embodiment of the present invention.

FIG. 18 is a side sectional view showing an example of a conventional molded body and the vicinity of a bead core intermediate body.

[Explanation of symbols] 21 ... Bead core intermediate 22 ... Bead cord 25 ... Pneumatic tire 26 ... Rigid core 28… Unvulcanized tire 33… Bead core 39… Rotary axis 43… Molding segment 44… Molded body 60… Molded segment 61 ... Molded body 73 ... Contact / separation means 74 ... Rotation means 75 ... Expansion / reduction means 77 ... Annular groove 81 ... Supplying means W ... Width L ... Radial straight line

Claims (6)

[Claims] 1. A bead core intermediate body which is formed by spirally winding one bead cord outward in the radial direction, and which is a bead core of a pneumatic tire by being superposed in the axial direction. , By displacing at least a part of the bead cord from the winding start position to the winding end position in the axial direction with respect to the radial straight line so that the cross-sectional shape of the bead core intermediate body is the final cross-sectional shape in the pneumatic tire. A bead core intermediate having a shape substantially the same as that of. 2. A pneumatic tire, wherein an outer surface of a rigid core having the same shape as an inner surface of the pneumatic tire is attached to the outside of a rigid core to form an unvulcanized tire, the tire constituent member and the bead core intermediate being adhered to each other. The bead core intermediate body according to claim 1, which is formed by vulcanizing an unvulcanized tire. 3. The bead core intermediate body according to claim 1, wherein the cross-sectional shape is a frustoconical shape that is displaced outward in the axial direction of the pneumatic tire as it goes outward in the radial direction. 4. A pair of molded products are assembled close to each other, and the width between these molded products is substantially equal to one bead cord, and the cross-sectional shape is the final cross-section of the bead cord in a pneumatic tire. So that the shape is almost the same,
A step of forming an annular groove at least a part of which is axially displaced with respect to a radial straight line; and a step of supplying one bead cord into the annular groove while integrally rotating the combined molded body, A step of forming a bead core intermediate body by spirally winding the bead cord outward in the radial direction in the annular groove, and a step of separating the molded body from each other and then taking out the bead core intermediate body from these formed bodies A method for producing a bead core intermediate, comprising: 5. A pair of molded products, and by combining these molded products in close proximity to each other, between these molded products,
The width is substantially equal to that of one bead cord, and the cross-sectional shape thereof is almost the same as the final cross-sectional shape of the bead cord in the pneumatic tire. The contacting / separating means for forming the annular groove displaced in the direction, the rotating means for integrally rotating the combined molded body, and the supply of one bead cord into the annular groove of the rotating molded body. A supply means for forming a bead core intermediate body by spirally winding the bead cord in a radial direction outward in the annular groove,
An apparatus for producing a bead core intermediate body, characterized in that after the bead core intermediate body is molded, the molded bodies are separated from each other by a contacting / separating means, and the bead core intermediate body is taken out from these molded bodies. 6. The pair of molded bodies are supported on the same rotary shaft so as to be integrally rotatable, and at least one of the molded bodies is supported on the rotary shaft so as to be movable in the axial direction,
And, each molding is composed of a plurality of molding segments arranged apart from each other in the circumferential direction, and an expansion / contraction means for expanding / contracting the moldings by synchronously moving the molding segments constituting each molding in the radial direction. The bead core intermediate manufacturing apparatus according to claim 5, further provided.