JP2006160053A - Pneumatic tire, and its manufacturing method - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To form a reinforcing layer 34 arranged on the outer side in the axial direction of a return part 20 with high accuracy and high efficiency while preventing air inclusion. <P>SOLUTION: A reinforcing layer 34 is constituted by spirally winding a single wire cord 38 bent in a zigzag manner or a wavy manner while being tightly fitted to each other, little air remains between a return part 20 and the single wire cord 38 because no axially overlapping portion is present in the reinforcing layer 34 before vulcanization, excessive rubber flow during the vulcanization is prevented, and array disturbance of a non-extensible cord 36 can be effectively suppressed. Further, since the single wire cord 38 is wire-like and the width thereof is very small, the non-extensible cord 36 is not longitudinally pulled even when the single wire cord is spirally wound, and the array disturbance of the non-extensible cord 36 can be further suppressed. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

    The present invention relates to a pneumatic tire in which a reinforcing layer is disposed on the outer side in the axial direction of a folded portion of a carcass layer and a method for manufacturing the same.

In order to improve the durability of the bead portion of the pneumatic tire, the present applicant has proposed the one described in Patent Document 1 below.
JP-A-9-193625

  This includes a pair of bead cores, a carcass layer comprising a substantially toroidal main body portion disposed between the bead cores and a folded portion folded around the bead core, and a belt layer disposed radially outward of the main body portion. A non-stretchable cord that extends in the circumferential direction while being bent in a wavy or zigzag manner in the reinforcing layer. Is embedded.

And it is possible to manufacture such a reinforcement layer using the method as described in the following patent document 2, for example.
JP 2000-203215 A

  That is, after forming a linear ribbon-like body by arranging a small number of non-stretchable cords bent in a wavy or zigzag manner and covering them with rubber, a large number of ribbon-like bodies are spirally formed outward in the axial direction of the folded portion. The reinforcing layer is formed by winding. Here, at the time of such molding, in order to make the cord interval constant, it is necessary to superimpose the half-moon region of rubber only where the cord is not driven onto the cord portion of the ribbon-like cord that has already been wound. is there.

    However, since the pneumatic tire manufactured using the method as described above is wound while overlapping the end portions in the width direction of the ribbon-shaped body, the space between the folded portion and the ribbon-shaped body is increased. In addition, there is a problem that air may remain, and the rubber at the overlapping portion at the time of vulcanization flows, so that the cord may be dragged and the arrangement may be disturbed. In addition, since a linear ribbon-like body covered with a small number of cords and covered with rubber is spirally wound, the cord disposed radially outside the ribbon-like body is pulled in the longitudinal direction, and the pitch becomes longer. There was also a problem that the amplitude was reduced and the arrangement of the code was disturbed.

  Furthermore, in the manufacturing method as described above, it is difficult to recognize the position and shape of the cord embedded in the ribbon-like body. It is difficult to wind the next ribbon-like body while adjusting the phase. As a result, there is a problem that the winding work is troublesome and the efficiency is lowered.

  An object of the present invention is to provide a pneumatic tire capable of forming a reinforcing layer disposed on the outer side in the axial direction of the folded portion with high accuracy and high efficiency while preventing air from entering, and a method for manufacturing the same. .

    Such a purpose is as follows. First, a reinforcing layer is provided on the outer side in the axial direction of the folded portion of the carcass layer including a substantially toroidal main body portion disposed between a pair of bead cores and a folded portion folded around the bead core. In the arranged pneumatic tire, the reinforcing layer is configured by closely arranging a single wire cord bent in a wavy or zigzag shape in which one non-extensible cord is coated with a coating rubber in a spiral shape along the circumferential direction. Can be achieved with pneumatic tires,

  Secondly, while the pair of bead cores are brought close to each other, internal pressure is supplied into the main body portion of the carcass layer to deform the main body portion into a substantially toroidal shape, and the carcass layer on the outer side in the width direction from the bead core is folded back around the bead core. While the folded portion is formed, single wire cords that are formed by coating one non-extensible cord with a coating rubber around the transfer member and wound in a wavy or zigzag manner are wound in a spiral shape while closely contacting each other. It can be achieved by a method for manufacturing a pneumatic tire comprising: a step of forming a reinforcing layer; and a step of pressing the transfer body against the folded portion to transfer the reinforcing layer from the transfer body to the outside in the axial direction of the folded portion. Can

  Third, while the pair of bead cores are brought close to each other, internal pressure is supplied into the main body portion of the carcass layer to deform the main body portion into a substantially toroidal shape, and the carcass layer on the outer side in the width direction from the bead core is folded back around the bead core. A step of forming a folded portion and a single wire cord formed by coating one non-extensible cord with a coating rubber directly on the outside in the axial direction of the folded portion while closely contacting each other with a single wire cord bent in a wavy or zigzag manner And a step of forming the reinforcing layer by winding in a shape.

    In the first aspect of the present invention, a single wire cord that is bent in a wavy or zigzag shape in which one non-extensible cord is coated with a coating rubber is closely attached in a spiral shape along the circumferential direction. Since the reinforcing layer is configured so that the one side end portion and the other side end portion are in contact with each other, there is no portion overlapping in the axial direction in the reinforcing layer before vulcanization. Almost no air remains between the single wire cords, and further, an excessive rubber flow at the time of vulcanization is prevented, and the disorder of the arrangement of the non-extensible cords is effectively suppressed. In addition, since the single-wire cord is linear and has almost no width, the non-extensible cord is not pulled in the longitudinal direction even if it is wound in a spiral shape, and the disorder of the arrangement of the non-extensible cord can be further suppressed. .

  In addition, in the invention described in claims 2 and 3, in addition to the effect described in claim 1, the following effect is also obtained. That is, the single wire cord is spirally wound around the transfer body and on the outer side in the axial direction of the folded portion. At this time, only one non-extensible cord is embedded in the single wire cord. Therefore, the position and shape can be easily and reliably recognized, which makes it easy to wind the next single wire cord while adjusting the cord interval and the wavy phase, and the winding work is easy. As a result, work efficiency improves.

  Here, if the reinforcing layer is formed by winding the single wire cord around the transfer body once as in claim 2, then the reinforcement layer is transferred from the transfer body to the folded portion, so that the winding object has high rigidity. Therefore, the reinforcing layer can be formed with high accuracy. Further, if the reinforcing layer is formed by winding the single wire cord directly outside the folded portion in the axial direction as described in claim 3, the working time can be shortened and the working efficiency can be improved.

According to the fourth aspect of the present invention, since it is only necessary to wind a single wire cord bent in advance, high-speed winding is possible and work efficiency is improved.
Furthermore, if it comprises as described in Claim 5, since a bending operation | work and a winding operation | work will be performed simultaneously by one means, this means can be reduced in size.

Embodiment 1 of the present invention will be described below with reference to the drawings.
1 and 2, 11 is a large pneumatic tire used for trucks, buses, etc., and this pneumatic tire 11 has a pair of bead cores 12 and a carcass layer 13, and this carcass layer 13 has a radial direction inside. It is composed of at least one carcass ply 15 (one in this embodiment) in which a large number of cords 14 extending in the meridian direction are embedded. The carcass layer 13 is disposed between the pair of bead cores 12 and extends in a substantially toroidal shape. The carcass layer 13 is disposed on the outer side in the axial direction of the main body 19 by being folded around the bead core 12 from the inside to the outside. In addition, it is constituted by a folded portion 20 extending substantially parallel to the main body portion 19 toward the outside in the radial direction.

  A belt layer 24 is disposed on the outer side in the radial direction of the carcass layer 13, and a tread 26 having a plurality of (here, four) main grooves 25 and the like is formed on the outer side in the radial direction of the belt layer 24. A side tread 27 made of rubber is disposed outside the carcass layer 13 in the axial direction. The belt layer 24 is composed of at least two belt plies, in this embodiment, two belt plies 30, and each belt ply 30 is non-stretched in a reverse direction at a predetermined angle with respect to the tire equator S. A large number of reinforcing cords made of steel, for example steel, are embedded.

  Reference numerals 34 denote reinforcing layers respectively arranged on the outer sides in the axial direction of the folded portion 20, and these reinforcing layers 34 are composed of at least one reinforcing ply, in this embodiment, one reinforcing ply 35. This reinforcing ply 35 has a single wire cord 38 that is bent in a wave shape or zigzag shape, in which one non-extensible cord 36 is covered with a coating rubber 37, closely attached in a spiral shape along the circumferential direction. The one side end portion 39 and the other side end portion 40 are arranged so as to contact each other.

  In this way, when the reinforcing layer 34 is composed of a zigzag or wavyly bent single-wire cord 38 disposed in close contact with the spiral, there is no portion overlapping in the axial direction in the reinforcing layer 34 before vulcanization. Almost no air remains between the folded portion 20 and the single wire cord 38. Further, excessive rubber flow at the time of vulcanization is prevented, and the disorder of the arrangement of the non-extensible cord 36 is effectively suppressed. Further, since the single wire cord 38 as described above is linear and has almost no width, the non-stretchable cord 36 is not pulled in the longitudinal direction even when wound in a spiral shape, and the arrangement of the non-stretchable cord 36 is disturbed. Can be further suppressed.

  Here, the aforementioned non-stretchable cord 36 is made of a stranded wire or a monofilament and made of a non-stretchable material such as steel or aromatic polyamide. The non-extensible cord 36 is bent in a wave shape or zigzag shape, for example, a sine wave, a square wave, or a triangular wave shape, in a plane parallel to the front and back surfaces of the reinforcing layer 34, and between the adjacent non-extensible cords 36. It arrange | positions so that a space | interval may become equal intervals.

Next, a method for manufacturing the pneumatic tire 11 as described above will be described.
3 and 4, reference numeral 43 denotes a horizontal first molding drum that is driven and rotated by a drive unit (not shown). The first molding drum 43 has a cylindrical shape and can be enlarged and reduced in two stages. When the tire forming members such as the carcass ply 15 are successively supplied from a supply device (not shown) to the rotating first forming drum 43 and wound around the periphery, the first forming drum 43 has a cylindrical intermediate portion. A band is formed.

  Further, only the central portion in the axial direction of the first forming drum 43 can be expanded and contracted in three stages, and a pair of folded bladders 46 and 47 capable of expanding and contracting are provided at both ends in the axial direction. . Then, after the intermediate band is formed as described above, when the axial central portion of the first forming drum 43 is expanded to the maximum diameter, the bead core 12 is moved outside the intermediate band by a bead supply device (not shown). The first molding drum 43 is set at a position where it abuts on the step between the axial central portion and both axial end portions.

  Next, when air is supplied into the folded bladders 46 and 47 to inflate the folded bladders 46 and 47, the folded bladder 46 is pushed down inward in the axial direction by the folded bladder 47, and thereby the outer side in the width direction from the bead core 12. In other words, the intermediate band formed of the carcass layers 13 and the like at both axial ends is folded back from the axially outer side toward the axially inner side around the bead core 12 to form the folded part 20 of the carcass layer 13. . In this way, a cylindrical green case 48 is formed around the first forming drum 43.

  Next, after the green case 48 is gripped from the outside in the radial direction by a conveying device (not shown), the first forming drum 43 is reduced in diameter to the minimum diameter, and the green case 48 is received from the first forming drum 43 by the conveying device. hand over. Thereafter, the green case 48 is transported to the second molding drum 51 by the transport device and is fitted to the radially outer side of the second molding drum 51. Next, the pair of bead supports 52 provided on the second forming drum 51 is expanded in diameter to support the bead cores 12 of the green case 48 from the inside in the radial direction.

  Thereafter, the pair of bead supports 52 are moved inward in the axial direction so as to approach each other, thereby bringing the pair of bead cores 12 closer to each other and the inside of the green case 48 between the bead cores 12, more specifically, the main body of the carcass layer 13 An internal pressure is supplied into 19 to deform the main body 19 into a substantially toroidal shape. At this time, since a belt tread band 53 including a cylindrical belt layer 24 and a tread 26 is supplied and arranged on the outer side in the radial direction of the green case 48, the green case 48 has a substantially toroidal shape. In the middle of deformation, the green case 48 is attached to the belt tread band 53, and the tire intermediate 54 is formed.

  While the tire intermediate body 54 is formed as described above, the reinforcing layer 34 disposed on the axially outer side of the folded portion 20 of the tire intermediate body 54 is formed as follows. In FIGS. 5 and 6, reference numeral 58 denotes a transfer body which has a substantially truncated cone shape and rotates around an axis upon receiving a driving force. The conical surface of the transfer body 58 is inclined at substantially the same angle as the folded portion 20. . Further, the transfer body 58 is made of metal and has high rigidity, but its conical surface is coated with plastic in order to reduce the adhesion to unvulcanized rubber.

  57 is a through-hole formed on the central axis of the transfer body 58, and a molding rod 59 is inserted into the through-hole 57 so as to be movable in the axial direction. It is wavy or zigzag-shaped along the circumferential direction. When the single wire cord 38 is wound around the transfer body 58, more specifically, on the conical surface, the mold rod 59 protrudes slightly from the transfer body 58 as shown in FIG. The single wire cord 38 is supported from the inside in the radial direction. On the other hand, the tip of the molding rod 59 is prevented from being pulled into the transfer body 58 immediately before the reinforcing layer 34 (single wire cord 38) is transferred from the transfer body 58 to the folding section 20, and damaging the folding section 20. Yes.

  62 is a bending means installed on the supply path of the single wire cord 38. The bending means 62 bends the straight single wire cord 38 in a zigzag shape or a wave shape having a predetermined amplitude and wavelength prior to winding. be able to. 61 is a pressure roller that is movable in the radial direction and the axial direction of the transfer body 58 and that rotates freely. The pressure roller 61 is applied to the transfer body 58 that is rotating by receiving a driving force at the winding position K. Thus, when the pre-bent single wire cord 38 is supplied, the single wire cord 38 is pressed against both the circumference of the transfer body 58 and the already wound single wire cord 38 while moving in the radial direction and the axial direction. The reinforcing layer 34 is formed by closely winding in a spiral manner with the interval between the non-extensible cords 36 adjacent to the periphery of the transfer body 58 being equal.

  In this way, the single wire cord 38 is wound around the transfer body 58 in a spiral shape. At this time, only one non-extensible cord 36 is embedded in the single wire cord 38. The position and shape can be easily and reliably recognized, which makes it easy to wind the next single-wire cord 38 while adjusting the cord interval and the wavy phase, making the winding work easier and Efficiency is improved. Further, if the single wire cord 38 is bent prior to winding as described above and the bent single wire cord 38 is supplied to the transfer body 58, it is only necessary to wind the previously bent single wire cord 38. Therefore, high-speed winding becomes possible and work efficiency is improved.

  Here, as shown in FIGS. 7 and 8, a pair of rollers 63 and 64 are rotatably supported by, for example, the tip of a robot arm, and the single-wire cord 38 supplied to the transfer body 58 in a linear state is The rollers 63 and 64 may be bent into a wave shape or a zigzag shape, and at the same time, may be tightly wound around the transfer body 58 in a spiral shape. In this way, the bending work and the winding work can be simultaneously performed by one means such as a robot, and the bending means 62 as described above becomes unnecessary, and the means can be miniaturized.

  When the reinforcing layer 34 is formed around the transfer body 58 in this way, the transfer body 58 is moved from the winding position K to the transfer position T, that is, to the outside in the axial direction of the folded portion 20 of the tire intermediate body 54. Then, the transfer body 58 is pressed against the folded portion 20 at the transfer position T, and the reinforcing layer 34 is transferred from the transfer body 58 to the outside in the axial direction of the folded portion 20 of the tire intermediate body 54. Thus, once the single wire cord 38 is wound around the transfer body 58 to form the reinforcing layer 34, the reinforcing layer 34 is transferred from the transfer body 58 to the folded portion 20 of the tire intermediate body 54. Since the object to be rotated is the highly rigid transfer body 58, the reinforcing layer 34 can be formed with high accuracy.

  Thereafter, a substantially tread-shaped side tread 27 as shown in FIG. 4 is attached to the outer side in the axial direction of the carcass layer 13 of the tire intermediate 54 to form a green tire. Next, after the green tire is gripped from the outside in the radial direction by a conveying device (not shown) and taken out from the second forming drum 51, it is carried into a vulcanizing device (not shown), and the green tire is removed by the vulcanizing device. Vulcanized to form a pneumatic tire 11.

  The pneumatic tire 11 as described above can also be manufactured by other manufacturing methods as shown in FIGS. In the manufacturing method shown in FIG. 9, the straight single-wire cord 38 is supplied to the tire intermediate 54, and the single-wire cord 38 is bent in a wave shape or zigzag shape by a pair of rollers 63 and 64 in the axial direction of the folded portion 20. The reinforcing layer 34 is formed by being wound in a spiral while being in close contact with each other.

  On the other hand, in the manufacturing method shown in FIG. 10, the single wire cord 38 bent into a wave shape or zigzag shape by the bending means 62 prior to winding is supplied to the tire intermediate 54, and the bent single wire cord 38 is supplied to the pressure roller 61. Thus, the reinforcing layer 34 is formed by being wound in a spiral while being in close contact with each other on the outer side in the axial direction of the folded portion 20. Thus, if the single wire cord 38 is wound directly around the folded portion 20 in the axial direction to form the reinforcing layer 34, the working time can be shortened and the working efficiency can be improved. Other configurations and operations are the same as those of the method for manufacturing the pneumatic tire 11 described above.

    In the above-described embodiment, after the carcass layer 13 on the outer side in the width direction from the bead core 12 is folded around the bead core 12 to form the folded portion 20, the main body portion 19 of the carcass layer 13 is deformed into a substantially toroidal shape. However, in the present invention, the carcass layer body portion may be deformed in a substantially toroidal shape, and then the carcass layer on the outer side in the width direction from the bead core may be folded around the bead core to form the folded portion.

    In the above-described embodiment, the transfer body 58 has a substantially truncated cone shape, and the single wire cord 38 is wound around the conical surface. However, in the present invention, the outer surface shape of the transfer body is the outer surface of the folded portion. A single wire cord may be wound around the outer surface of the transfer body in a complementary relationship with the shape.

  The present invention can be applied to the industrial field of pneumatic tires having a reinforcing layer formed in a bead portion formed by winding a single wire cord in a spiral shape.

It is meridian sectional drawing which shows Example 1 of this invention. It is the II arrow directional view of FIG. 1 where one part was fractured | ruptured. It is front sectional drawing explaining the shaping | molding state of a green case. It is meridian sectional drawing explaining the shaping | molding state of a tire intermediate body. It is a front view explaining the shaping | molding state of a reinforcement layer. FIG. 6 is a right side view of FIG. 5. It is a front view explaining the shaping | molding state of a reinforcement layer. FIG. 8 is a right side view of FIG. 7. It is the side view where a part explaining the fabrication state of a reinforcement layer was fractured. It is the side view in which one part explaining another shaping | molding state of a reinforcement layer was fractured | ruptured.

Explanation of symbols

11 ... Pneumatic tire 12 ... Bead core
13 ... Carcass layer 19 ... Main body
20 ... Folding part 34 ... Reinforcing layer
36 ... Non-extensible cord 37 ... Coating rubber
38 ... single wire cord 58 ... transcript

Claims (5)

    In the pneumatic tire in which the reinforcing layer is disposed on the axially outer side of the folded portion of the carcass layer including the substantially toroidal main body portion disposed between the pair of bead cores and the folded portion folded around the bead core. The pneumatic tire is characterized in that the layer is formed by closely arranging a single wire cord that is bent in a wavy or zigzag shape, in which one non-extensible cord is coated with a coating rubber, in a spiral shape along the circumferential direction.     While the pair of bead cores are brought close to each other, internal pressure is supplied into the main body portion of the carcass layer to deform the main body portion into a substantially toroidal shape, and the carcass layer on the outer side in the width direction from the bead core is folded around the bead core to form a folded portion. On the other hand, a single layer of cord that is formed by coating one non-extensible cord with a coating rubber around the transfer body is wound in a spiral shape while closely adhering to each other to form a reinforcing layer. And a step of pressing the transfer body against the folded portion and transferring the reinforcing layer from the transfer body to the outside in the axial direction of the folded portion.     While the pair of bead cores are brought close to each other, internal pressure is supplied into the main body portion of the carcass layer to deform the main body portion into a substantially toroidal shape, and the carcass layer on the outer side in the width direction from the bead core is folded around the bead core to form a folded portion. And a single wire cord that is formed by coating one non-extensible cord with a coating rubber directly on the outer side in the axial direction of the folded portion and wound in a spiral shape while being in close contact with each other. And a step of forming a reinforcing layer. A method for producing a pneumatic tire, comprising:     The method for manufacturing a pneumatic tire according to claim 2 or 3, wherein the single wire cord is bent into a wave shape or a zigzag shape prior to winding.     The method for manufacturing a pneumatic tire according to claim 2 or 3, wherein the single wire cord is bent into a wave shape or a zigzag shape simultaneously with winding.

Images