JP5588208B2 - Tire manufacturing method and tire - Google Patents

Description

  The present invention relates to a tire manufacturing method in which a resin material is injected into a mold and a tire frame member is formed, and to a tire.

Conventionally, a tire formed of rubber, an organic fiber material, and a steel member is known. In recent years, from the viewpoint of weight reduction and ease of recycling, it is required to use a resin material for a tire. The resin material described here is a concept that includes a thermoplastic resin or a thermosetting resin, and also includes a resin that is cross-linked by heat or an electron beam or a resin that is cured by thermal dislocation.
For this reason, for example, Patent Document 1 proposes forming a tire frame member by covering a bead core with a thermoplastic elastomer (TPE).

JP 05-116504 A

By the way, in such a tire skeleton member, if a rubber-coated strand bead core used in a conventional rubber tire is used as a bead core, it is not preferable from the viewpoint of adhesion or vulcanization, and therefore a cable bead core is often used as the bead core. . However, in the cable bead core, in addition to increasing the cost, it is difficult to allow the resin material to sufficiently enter between the cords when the tire frame member is formed of the resin material.
In view of the above fact, an object of the present invention is to provide a tire manufacturing method and a tire capable of sufficiently forming a resin material between cords.

According to the first aspect of the present invention, a cord is formed by coating a cord with a thermoplastic resin material, and the cord is formed into a bead shape while welding the thermoplastic resin materials of the coated cord. A coated bead filled with a thermoplastic resin material with no gap is formed, and the coated bead is brought into contact with a jig provided in a cavity of a mold for molding a tire frame member, and the coated bead is placed in the mold. Is fixed, and a molten thermoplastic resin material is injected into the cavity to form a tire frame member having the coated bead in the tire bead portion.
The invention according to claim 2 is a bead shape in which a cord is coated with a thermoplastic resin material to form a coated cord having an outer shape of a triangle or a quadrangle, and the thermoplastic resin materials of the coated cord are welded or bonded together. Forming a coated bead filled with a thermoplastic resin material without a gap between the cords, and contacting the coated bead with a jig provided in a cavity of a mold for molding a tire frame member Then, the coated bead is fixed in the mold, and a molten thermoplastic resin material is injected into the cavity to form a tire frame member having the coated bead in the tire bead portion.

Herein deterministic tire skeleton member, typically a toroidal shape.
In the first and second aspects of the invention, when forming the covering cord, the resin material and the cord are formed so as to adhere to each other. For example, the outer peripheral side of the cord is coated with a thermoplastic molten resin material, and the molten material is solidified by cooling to become a thermoplastic material, thereby forming a coated cord.
Further, in the invention according to claim 1, to form a coating bead by a resin material together a plurality of covering codes by dissolved wear it will give way. In the invention according to claim 2, the coated beads are formed by bonding and forming resin materials of a plurality of coated cords. Therefore, in the coated bead, the resin material adhered to the cord is formed in advance between the cords.
When forming the coated bead, one coated cord may be spirally wound or formed using a plurality of coated cords.

The coated bead thus formed is fixed in the mold. At that time, the covering bead is brought into contact with and fixed to a jig provided in the cavity of the mold. Then, the tire frame member is molded by closing the mold and injecting the molten resin material into the cavity.
Therefore, in the tire frame member formed in this way, the resin material is sufficiently formed between the cords.

The molten resin material (thermoplastic material, thermosetting material, etc.) may be injected at a high pressure for injection molding. The tire frame member may be formed in a tube shape so that air can be filled in the tire frame member.
In addition, when a molten thermoplastic material (thermoplastic molten material) is used as the molten resin material, a thermoplastic elastomer (TPE) having a rubber-like elasticity, a thermoplastic resin, or the like can be used. However, it is preferable to inject a thermoplastic elastomer in consideration of elasticity during running and moldability during production.

The invention described in claim 1 uses a thermoplastic material as the resin material. As a result, the molten thermoplastic material can be injected into the cavity and the thermoplastic material can be solidified by removing heat from the inner wall of the cavity, so that the tire can be easily manufactured. Moreover, since reuse is easy, effective use of resources is possible.

According to a third aspect of the present invention, when the covering cord is formed, a plurality of the cords are bundled and covered with a resin material so that no gap is formed between the cords.
Thereby, even when the covering cord per one has a plurality of cords, it is avoided that a gap is formed between the cords.

  The invention according to claim 4 uses a steel cord as the cord. Thereby, the strength and heat resistance of the cord can be greatly increased.

According to a fifth aspect of the present invention, when the covering bead is brought into contact with the jig, it is brought into contact with the jig from the direction of the tire inner side.
In the invention according to claim 5, since the jig is in contact with the inside of the tire of the tire frame member, there is a portion where the resin material injected into the mold is not formed. There is no effect on air retention when assembling the rim. Therefore, it is possible to obtain a jig size and shape that sufficiently secures the prevention of breakage of the thermoplastic material around the coated bead when the pot is removed.

According to a sixth aspect of the present invention, the molten resin material is injected from the tire bead portion side.
In the invention described in claim 6, when the molten resin material is injected, the molten resin material passes through the outer surface of the coated bead at the position where the jig is provided. For this reason, the covering bead is pressed from the tire outer side toward the tire inner side. Therefore, the moving force received by the coated bead during injection can be sufficiently supported by the jig.

In the invention according to claim 7, a plurality of the jigs are arranged along the circumferential direction of the cavity.
Thereby, the position accuracy of a covering bead can be improved more.

According to an eighth aspect of the present invention, a skeleton portion from the tire bead portion to a tire center is formed as the tire skeleton member.
In the invention according to claim 8, the tire frame member constituting the tire half is formed. Therefore, by joining two tire frame members at the tire center, a frame member with a coated bead for the entire tire can be formed.

Invention of Claim 9 is a tire manufactured with the manufacturing method of the tire of any one of Claims 1-8.
In the invention according to claim 9, in the coated bead, the resin material adhered to the cord is formed in advance between the cords. Accordingly, since the resin material is sufficiently formed between the cords in the tire frame member formed when the tire is manufactured, the resin material is sufficiently formed between the cords even in the manufactured tire.
In the invention according to claim 10, an adhesive treatment for adhering the cord and the thermoplastic resin material is performed in advance before coating with the thermoplastic resin material.

  ADVANTAGE OF THE INVENTION According to this invention, it can be set as the tire manufacturing method and tire which can fully form resin material between cords.

1 (A) and 1 (B) are a mold used in an embodiment of the present invention, respectively, a plan sectional view at a position where a jig contacting the inside of the coated bead is provided, and It is a partial expanded sectional view in the position where the auxiliary jig which touches was provided. In one embodiment of the present invention, it is a perspective view showing that a coating bead is formed by thermally welding coating resins of adjacent coated steel cords. It is side surface sectional drawing which shows the tire frame member of the whole tire. In one Embodiment of this invention, it is a perspective view which shows the modification of heat-welding the coating resin of adjacent coating steel cords, and forming a coating bead.

Hereinafter, an embodiment using a thermoplastic material as a resin material will be cited and an embodiment of the present invention will be described. In the present embodiment, the thermoplastic molten material means a molten material of the thermoplastic material, and the thermoplastic material means a solidified material.
In one embodiment of the present invention, a mold 10 as shown in FIG. 1 is used. As shown in FIG. 3, the mold 10 includes an outer mold 12 for molding the tire outer surface side and a tire so that a tire frame member 20 constituting the bead portion B to the tire center CL can be molded. And an inner mold 14 for molding the inner surface side. The inner die 14 is provided with a main jig 16 for fixing the coated beads. A cavity S (space) in the shape of a tire frame member is formed between the outer mold 12 and the inner mold 14.

In the present embodiment, twelve main jigs 16 are arranged along the accommodation position of the covering beads 11 at regular intervals, for example.
The main jig 16 is formed with a concave portion 17 corresponding to the outer shape of the coated bead 11 described later. When the coated bead 11 is placed in the mold 10, a part of the coated bead 11 enters the concave portion 17. Will be held. As a result, the covering bead 11 is in a state where movement in the tire inner direction is restricted and movement in the vertical direction (tire radial direction) is also restricted.

  Further, the gate (resin injection path) 18 of the mold 10 is formed so that the thermoplastic molten material passes through the outer side of the tire of the coated bead 11 with the coated bead 11 entering the recess 17. This molten material is, for example, in a molten state of a thermoplastic elastomer (TPE) or a thermoplastic resin.

  The gate 18 is a disk gate opened in a ring shape, and the cavity S is formed so as to communicate with the ring-shaped gate 18 and spread in a hollow disk shape. The gate 18 may be a pin gate, but from the viewpoint of formability, the disk gate is more preferable in this way.

In the present embodiment, the coated bead 11 is disposed in a predetermined position in the mold 10 and a thermoplastic molten material (often a molten thermoplastic polymer material) is injected, and the tire half on one side is injected. The tire skeleton member 20 (see FIG. 3) is formed.
And as shown in FIG. 3, the tire one side half part and the tire other side half part are joined by the tire center CL, and the tire frame member Z for the whole tire is formed.

  Furthermore, as a reinforcement of the crown portion, the steel cord K is wound in a spiral manner in the tire circumferential direction to increase the circumferential rigidity. Furthermore, the steel cord K may be embedded in the tire frame member Z. Moreover, the rubber material G1 is affixed to the site | part fitted to a wheel (rim flange), and the fitting property to a rim is improved. In addition, a rubber material (tread rubber G2) is attached to a portion in contact with the road surface to improve wear resistance and breakage resistance.

  Hereinafter, the operation and effect of manufacturing the tire frame member 20 by manufacturing a bead and placing it in the mold 10 and injection molding a thermoplastic molten resin will be described. Although the present embodiment will be described by injection molding, a thermoplastic material (thermoplastic resin) may be molded by simply injecting a thermoplastic molten material.

  In the present embodiment, first, a large number of coated steel cords 13 formed by coating a steel cord 13S with a thermoplastic resin are manufactured. In the coated steel cord 13, the outer peripheral side of the steel cord 13S is entirely covered with a coating resin 13R. The steel cord 13S is made of, for example, a metal monofilament or a metal stranded wire.

  In order to form such a coating resin 13R on the steel cord 13S, for example, a thermoplastic molten material is coated on the outer peripheral side of the steel cord, and the molten material is solidified by cooling to become a thermoplastic material. Code. Moreover, you may use an extruder. The outer shape of the resin as it comes out of the extruder can be round or triangular (see, for example, a coated steel cord 19 in which a steel cord 19S is coated with a coating resin 19R as shown in FIG. 4) or a square (rectangle or rhombus). Etc.) or a chamfered shape, and is not particularly limited.

  In addition, it is preferable to perform the adhesion | attachment process for adhere | attaching a metal and coating resin 13R previously before coating | covering. Specifically, a silane coupling agent is applied extremely thinly. A degreasing treatment prior to the adhesion treatment is more preferable from the viewpoint of adhesion.

  Next, as shown in FIG. 2, the manufactured coated steel cord 13 is wound around a winding jig at least once, and the coated resin portions 13RP of the coated steel cord portions adjacent to each other are thermally welded to each other to coat the coated beads 11 (For example, a strand bead coated with a resin or a monostrand bead) is formed.

The winding side of the winding jig has the same dimensions as the inner periphery of the coated bead 11. The number of windings is preferably 2 or more from the viewpoint of stabilizing the strength. When the number of windings is 1, it is preferable to generate an overlap portion of 10 mm or more at the start and end of winding. This is because if the thickness is less than 10 mm, the welding force of the coating resin portion 13RP heat-welded at the time of injection molding is so weak that it can be easily detached.
When the heat welding is performed, the coating resin portion 13RP may be melted with hot air and re-solidified, or the tip having a high temperature is brought into contact with the coating resin portion 13RP to be melted and re-solidified. May be welded. Further, the iron may be brought into contact with the hot air.

  The coating resin 13R is preferably the same type as a thermoplastic resin constituting the tire skeleton member 20 described later, but may be a different resin as long as it is a resin that adheres to the thermoplastic resin. In the case of a different kind of resin, it is preferable that the Young's modulus of the coating resin 13R is in the range of 0.05 to 10 times that of the thermoplastic resin constituting the tire frame member 20. If it is 11 times or more, it is considered that the rigidity of the coated bead 11 becomes too high and it is difficult to assemble the rim. On the other hand, if it is smaller than 0.05 times, the rigidity of the coated bead 11 becomes too low, and it is considered that the coated bead 11 is easily separated without being able to withstand the pressure of the molten resin at the time of injection molding.

  Next, the mold 10 is opened, the tire inner side portion of the coated bead 11 manufactured in this way is put in the concave portion 17 of the main jig 16, the coated bead 11 is held by the main jig 16, and the mold 10 is closed, The auxiliary jig 22 supports the outside of the tire of the coated bead 11.

Then, the thermoplastic molten resin F is injected from the gate 18 into the mold 10 and injection molded to form the tire frame member 20.
In this injection molding, at the position where the main jig 16 is provided, the molten resin F is injected from the gate 18 so as to pass between the covering bead 11 and the outer mold 12, so that the covering bead 11 is a tire. It is pressed from the outside toward the inside of the tire. Therefore, the moving force received by the coated bead 11 can be sufficiently supported by the main jig 16.

  As described above, in the present embodiment, when the coated beads 11 are formed, the coating resin portions adjacent to each other of the coated steel cord 13 are thermally welded. Therefore, the resin is sufficiently formed between the cords in the coated bead 11. Therefore, in the tire frame member 20 formed by arranging the coated bead 11 in the mold 10 and the pneumatic tire T using the tire frame member 20, a resin is sufficiently formed between the cords of the coated bead 11. ing.

  Further, each steel cord 13S of the bead portion B is covered with a coating resin 13R over the entire circumference. Therefore, since the portion where the steel cord 13S is exposed is not formed, the steel cord 13S is reliably prevented from being rusted.

  In addition, a thermoplastic molten material is injected into the cavity S in a state in which the covering bead 11 is in contact with the main jig 16 from the direction inside the tire. That is, it is possible to inject the thermoplastic molten material in a state where the auxiliary jig 22 for preventing the positional deviation of the coated bead 11 is brought into contact with the coated bead 11 in a slight region from the outside of the tire. Therefore, on the outer side of the formed tire frame member 20, the portion where the injection molded thermoplastic material (thermoplastic resin) is not formed due to the contact of the auxiliary jig 22 is a small area even if formed. It is. Therefore, the air retainability when assembling the rim is ensured.

  Then, a portion where the coated bead 11 is exposed without forming the injection-molded thermoplastic material due to the main jig 16 being in contact with the inside of the tire frame member 20 is formed, but this portion is large. There is no effect on air retention when assembling the rim. Therefore, it is possible to obtain a jig size and shape that sufficiently ensure the prevention of breakage of the thermoplastic material around the coated bead 11 when the pot is pulled out, and sufficiently suppress the displacement of the coated bead 11 when the tire is molded. Can do.

  The auxiliary jig 22 may have a mold structure capable of moving back and forth into the cavity, and the molten resin may be continuously injected while the auxiliary jig 22 is retracted. As a result, the molten resin can be injected before the already injected molten resin is too solidified. Therefore, the molten resin can flow into the portion where the auxiliary jig 22 is in contact, and a thermoplastic material can be formed. Furthermore, the main jig 16 can be similarly moved forward and backward, so that the molten resin can flow into the portion where the main jig 16 is in contact to form a thermoplastic material. In this case, the timing for retracting the auxiliary jig 22 and the main jig 16 from the coated bead 11 is determined in advance based on the dimensions of the cavity S and the temperature of the thermoplastic molten resin injected into the cavity S. Therefore, it is not necessary to detect the solidified state of the injected molten resin.

Further, when the covering bead 11 is held by the main jig 16 to sufficiently prevent the positional deviation of the covering bead 11 at the time of pouring the molten resin, the molten resin can be removed without using the auxiliary jig 22. It may be injected.
Moreover, it is also possible to make the main jig 16 contact from the tire outer side instead of the tire inner side.

  Moreover, when injecting molten resin, it inject | pours from between the coating bead 11 and the outer metal mold | die 12 which forms the tire outer side. For this reason, the covering bead 11 is pressed from the tire outer side toward the tire inner side at the time of injection. Therefore, the moving force received by the coated bead 11 can be sufficiently supported by the main jig 16. Further, when the molten resin is injected, such an effect can be obtained even if it is injected at a high pressure for injection molding.

  Further, jigs 16 are arranged at a plurality of positions along the circumferential direction of the cavity S. Thereby, the position accuracy of the covering bead 11 can be further improved.

  Further, as the tire frame member 20, a frame part from the bead part B to the tire center CL is formed. That is, the tire skeleton member 20 constituting the tire half is formed. Accordingly, by joining the two tire frame members at the tire center CL, a frame member with a coated bead for the entire tire can be formed. This joining is performed by a welding method using a molten resin or a hot plate welding method. The joining member 21 joined at the tire center CL may be formed of the same type of resin as the tire skeleton member 20 or may be formed of a different type of resin from the tire skeleton member 20.

  In the present embodiment, the tire skeleton member 20 constituting the tire half is formed. However, the present invention is not limited to this, and a tube-shaped tire skeleton member is formed, and the inside of the tire skeleton member is formed. A structure that can be filled with air may be used. In addition, a toroidal tire frame member may be formed.

Further, in the present embodiment, the thermoplastic molten resin is injected into the cavity as the thermoplastic molten material, but a molten thermoplastic elastomer (TPE) may be injected.
Examples of the thermoplastic elastomer include an amide thermoplastic elastomer (TPA), an ester thermoplastic elastomer (TPC), an olefin thermoplastic elastomer (TPO), a styrene thermoplastic elastomer (TPS) defined in JIS K6418, Examples thereof include a urethane-based thermoplastic elastomer (TPU), a crosslinked thermoplastic rubber (TPV), and other thermoplastic elastomers (TPZ). Examples of the thermoplastic synthetic resin include urethane resin, olefin resin, vinyl chloride resin, polyamide resin, and the like.

  Furthermore, as these thermoplastic materials, for example, the deflection temperature under load specified at ISO 75-2 or ASTM D648 (at the time of 0.45 MPa load) is 75 ° C. or higher, the tensile yield strength specified by JIS K7113 is 10 MPa or higher, Similarly, the tensile yield elongation specified by JIS K7113 is 10% or more, the tensile fracture elongation specified by JIS K7113 is 50% or more, and the Vicat softening temperature (Method A) specified by JIS K7206 is 130 ° C or more. Things can be used.

  The embodiments of the present invention have been described with reference to the embodiments. However, the above embodiments are merely examples, and various modifications can be made without departing from the scope of the invention. For example, although a thermoplastic material is used as the resin material, a tire may be manufactured using a thermosetting resin such as a urea resin or a phenolic resin, and the resin material used in the present invention is a thermoplastic material. Is not limited. Needless to say, the scope of rights of the present invention is not limited to the above embodiment. In the present embodiment, the coated resin portions 13RP of the coated steel cord portions adjacent to each other are thermally welded to each other to form the coated beads 11. However, the coated beads may be formed by bonding without being limited to welding. Needless to say, the scope of rights of the present invention is not limited to the above embodiment.

10 Mold 11 Coated Bead 13 Coated Steel Cord (Coated Cord)
13S Steel cord (Cord)
16 Main jig (jig)
19 Coated steel cord (coating cord)
19S Steel cord (code)
20 Tire frame member 22 Auxiliary jig (jig)
B Bead part (tire bead part)
CL Tire Center S Cavity S

Claims (10)

Forming a coated cord formed by coating the cord with a thermoplastic resin material;
Wherein by a thermoplastic resin material between the covered cord will give shape to the bead while dissolved deposited to form a coating bead between codes has been filled with the thermoplastic resin material without a gap,
Fixing the coated bead in the mold by bringing the coated bead into contact with a jig provided in a cavity of a mold for molding the tire frame member;
A tire manufacturing method in which a tire frame member having the coated beads is formed in a tire bead portion by injecting a molten thermoplastic resin material into the cavity. The cord is coated with a thermoplastic resin material to form a coated cord whose outer shape is triangular or quadrangular,
  By forming a bead shape while welding or adhering the thermoplastic resin materials of the coated cord, forming a coated bead filled with a thermoplastic resin material without a gap between the cords,
  Fixing the coated bead in the mold by bringing the coated bead into contact with a jig provided in a cavity of a mold for molding the tire frame member;
  A tire manufacturing method in which a tire frame member having the coated beads is formed in a tire bead portion by injecting a molten thermoplastic resin material into the cavity. The tire manufacturing method according to claim 1 or 2, wherein when forming the covering cord, a plurality of the cords are bundled and covered with a thermoplastic resin material so that no gap is formed between the cords.   The tire manufacturing method according to claim 1, wherein a steel cord is used as the cord.   The method for manufacturing a tire according to claim 4, wherein when the coated bead is brought into contact with the jig, the jig is brought into contact with the jig from a direction inside the tire. The method for manufacturing a tire according to claim 5, wherein a molten thermoplastic resin material is injected from the tire bead portion side.   The tire manufacturing method according to claim 1, wherein a plurality of the jigs are arranged along a circumferential direction of the cavity.   The tire manufacturing method according to claim 1, wherein a skeleton portion from the tire bead portion to a tire center is formed as the tire skeleton member.   A tire manufactured by the tire manufacturing method according to claim 1. The tire manufacturing method according to any one of claims 1 to 8, wherein an adhesive treatment for adhering the cord and the thermoplastic resin material is performed in advance before the coating with the thermoplastic resin material. .

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