JP2011207435A - Tire and method for manufacturing the same - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a tire with high internal pressure holding performance in a rim-assembled state, even when a tire skeleton member is formed by a resin material, and a method for manufacturing the tire.SOLUTION: A chafer 24 is formed to abut on a bead seat part 21 and a rim flange 22 of a rim 20 on a surface of a bead part 12 of the tire skeleton member 17. The chafer 24 is formed at a position abutting on the bead seat part 21 and the rim flange 22 of the rim 20 on at least the surface of the bead part 12. When a tire 10 is assembled to the rim 20, the chafer 24 adheres to the rim 20 to seal a gas filling space in the tire 10. An elastic modulus of the chafer 24 is lower than that in the tire skeleton member 17.

Description

  The present invention relates to a tire provided with a tire frame member made of a resin material constituting at least a bead portion, and a method for manufacturing the tire.

  Conventionally, a tire formed of rubber, an organic fiber material, and a steel member is known. In recent years, a thermoplastic polymer material such as a thermoplastic elastomer (TPE) or a thermoplastic resin is required to be a tire frame member from the viewpoint of weight reduction, productivity, and ease of recycling. From the viewpoint of weight reduction, it is required to use a thermosetting resin material as a tire frame member. For this reason, for example, Patent Document 1 discloses that a tire frame member is formed by covering a bead core with a thermoplastic elastomer.

Japanese Patent Laid-Open No. 03-143701

  However, in Patent Document 1, since the thermoplastic material itself has high rigidity, the rim fit property is not sufficient. For this reason, there is a problem that it is difficult to maintain a necessary internal pressure for a long time even if the tire is assembled with a rim and gas (air) is filled in the tire.

  The present invention has been made in consideration of the above facts, and even when a tire frame member is formed of a thermoplastic material, a tire having high internal pressure retention performance in a rim assembled state, and the tire It is an object to provide a manufacturing method.

  The tire according to claim 1 is made of a resin material, and is provided in a close contact portion between a tire skeleton member having at least a bead portion and at least a rim of the bead portion of the tire skeleton member. And a chafer made of a resin material having a low elastic modulus.

Here, the resin material of the present application refers to a thermoplastic resin, a thermoplastic elastomer, a thermosetting resin, and the like, and is a material that does not contain vulcanized rubber. The thermoplastic material includes a thermoplastic material that is cured by electron beam crosslinking or ultraviolet crosslinking.
Similarly, a chafer made of a resin material is also a chafer mainly composed of a thermoplastic resin, a thermoplastic elastomer, a thermosetting resin, etc., which is a general rubber tire. It corresponds to a rubber chafer. Note that the material constituting the chafer and the material constituting the tire frame member may be the same material or different materials.

  In the first aspect of the invention, when the tire rim is assembled (assembly of the tire and the rim), the chafer is brought into close contact with the rim, and a gas-filled space is formed in the tire. Since the chafer has an elastic modulus lower than that of the tire frame member, the sealing performance at the contact portion between the chafer and the rim is higher than when the tire frame member itself is in close contact with the rim. Therefore, since the gas (air) filled in the gas filling space is difficult to escape from between the tire (bead part) and the rim, the internal pressure holding performance of the tire in the assembled state of the rim can be improved. .

  The tire according to a second aspect of the present invention is characterized in that an elastic modulus of the chafer is 0.5 Mpa or more and 50 Mpa or less.

  When the elastic modulus of the chafer is less than 0.5 Mpa, it is considered that the compression creep property of the portion closely contacting the rim is not sufficient, and a gap is formed between the rim and the chafer's elastic modulus. In the case of more than 50 Mpa, the compressive deformation of the portion closely contacting the rim cannot be sufficiently obtained, and it is considered that a gap is formed between the rim and the chafer has an elastic modulus of 0.5 Mpa or more, It is preferable that it is 50 Mpa or less.

  The tire according to a third aspect of the invention is characterized in that the chafer extends to a side portion.

  Here, the side part in this specification means from the bead part to the tread end. Here, the tread end means that the tire is mounted on a standard rim prescribed in JATMA YEAR BOOK (2009 edition, Japan Automobile Tire Association Standard) and the maximum load capacity in the applicable size / ply rating in JATMA YEAR BOOK ( Fills 100% of the air pressure (maximum air pressure) corresponding to the internal pressure-load capability correspondence table as the internal pressure, and indicates the outermost ground contact portion in the tire width direction when the maximum load capability is applied. In addition, when TRA standard and ETRTO standard are applied in a use place or a manufacturing place, it follows each standard.

  Thus, by extending the chafer to the side part, the part from the bead part to the side part can be protected, and damage to the tire frame member due to curb rubbing or the like can be suppressed. Note that the chafer may extend near the tread or inside the tread.

  The tire according to a fourth aspect of the present invention is characterized in that a thickness of a portion corresponding to the side portion of the chafer is 0.2 mm or more and 4.0 mm or less.

  When the thickness of the portion corresponding to the side portion of the chafer is less than 0.2 mm, there is little protection against damage to the tire frame due to curb rubbing or the like, and when it exceeds 4.0 mm, the tire weight increases. Therefore, the thickness of the portion corresponding to the side portion of the chafer is preferably 0.2 mm or more and 4.0 mm or less.

  The tire according to claim 5 is characterized in that the chafer extends to the inside of the gas filling space of the bead portion.

  In this way, by extending the chafer to the inside of the gas filling space of the bead part, curling of the edge of the chafer is suppressed when assembling the rim, compared to the case where the chafer is provided only on the tire outer side of the bead part. be able to.

  A tire manufacturing method according to a sixth aspect of the present invention is the tire manufacturing method according to any one of the first to fifth aspects, comprising a resin material and comprising at least a bead portion. The member is molded, and at least the bead portion of the tire frame member is accommodated in the cavity in the chafer forming mold, and the dividing surface of the chafer forming mold is set in an unclosed state from the tire frame member. A chafer material made of a resin material having a low elastic modulus is injected into the chafer forming mold, the chafer forming mold is completely closed, and the injected chafer material is compressed. , To form a chafer.

  In the tire manufacturing method of the present invention, a tire frame member is first molded, and at least a bead portion of the tire frame member is accommodated in a cavity in a chafer forming mold. At this time, the dividing surface of the chafer forming mold is kept in a non-closed state. Here, the non-closed state of the dividing surface means a state in which the divided chafer forming mold is slightly opened on the dividing surface, and means an opening of about 0.1 mm to 4.0 mm.

  Next, a chafer material having an elastic modulus lower than that of the tire frame member is injected into the chafer forming mold. Then, the chafer forming mold is completely closed, and the injected chafer material is compressed to form the chafer.

  Thus, by compressing the chafer material after injection to form the chafer, it is possible to make it difficult to cause molecular orientation of the chafer material. Further, residual stress and deformation of the formed chafer can be reduced.

  In the tire manufacturing method according to claim 7, when the bead portion is accommodated in the chafer forming mold, the bead portion is brought into contact with the cavity in the chafer forming mold. A holding jig for holding the position of the bead portion is arranged.

  In this way, by holding the bead portion of the tire frame member with the holding jig, it is possible to prevent positional deviation of the bead portion within the cavity when the chafer material is injected.

  In the tire manufacturing method according to claim 8, the holding jig is allowed to exit from the cavity after the chafer material is injected and before the chafer forming mold is completely closed. Features.

  In this way, when the chafer forming die is completely closed after leaving the holding jig out of the cavity, the portion of the chafer material injected into the cavity is compressed and the holding jig is arranged. Get in. Thereby, a chafer can be formed without making a hole also about the part in which the holding jig was arrange | positioned.

  According to the present invention, even if the tire frame member is formed of a resin material, a tire having high internal pressure retention performance can be obtained.

(A) based on 1st Embodiment is sectional drawing of a pneumatic tire, (B) is a partial expansion perspective sectional view when a pneumatic tire is mounted | worn to a rim | limb. The metal mold | die used by 1st Embodiment, (A) is sectional drawing in the position in which the jig | tool contact | abutted to a bead core was provided, (B) is a partial expansion in the position in which the jig | tool contact | abutted to a bead core is not provided. It is sectional drawing. In the tire skeleton member formed in the first embodiment, (A) is a partial perspective view in a state where a bead core is embedded, and (B) is a partial perspective view shown without drawing a bead core. (A) of the tire frame member formed in the first embodiment is a side view seen from the inside of the tire, and (B) is a partially enlarged view of (A). It is sectional drawing of the metal mold | die for chafers in the division | segmentation state of 1st Embodiment. It is sectional drawing which shows the state which set the tire frame member half body to the metal mold | die for chafers of 1st Embodiment. It is sectional drawing which shows the state by which the metal mold | die for chafers of 1st Embodiment is not closed. It is sectional drawing which shows the state in which the resin for chafers is inject | poured into the metal mold | die for chafers of 1st Embodiment. It is sectional drawing which shows the state by which the metal mold | die for chafers of 1st Embodiment is completely closed. It is sectional drawing which shows the state which opens the metal mold | die for chafers of 1st Embodiment, and can take out a tire frame member half body. It is a perspective view of a tire frame member half body in which a chafer of the first embodiment is formed. It is sectional drawing which shows the uneven | corrugated example (A)-(C) of the bead structure part of 1st Embodiment. (A) which concerns on 2nd Embodiment is sectional drawing of a pneumatic tire, (B) is a partial expansion perspective sectional view when a pneumatic tire is mounted | worn to a rim. It is sectional drawing which shows the state which set the tire frame member half body to the metal mold | die for chafers of 2nd Embodiment. It is sectional drawing which shows the state by which the metal mold | die for chafers of 2nd Embodiment is not closed. It is sectional drawing which shows the state in which the resin for chafers is inject | poured into the metal mold | die for chafers of 2nd Embodiment. It is sectional drawing which shows the state by which the metal mold | die for chafers of 2nd Embodiment is completely closed. It is sectional drawing which shows the state which opens the metal mold | die for chafers of 2nd Embodiment, and can take out a tire frame member half body. It is a perspective view of the tire frame member half body in which the chafer of 2nd Embodiment was formed.

  Hereinafter, embodiments will be described and embodiments of the present invention will be described.

[First Embodiment]
First, the first embodiment will be described. As shown in FIGS. 1A and 1B, the pneumatic tire 10 according to the present embodiment includes a pair of bead portions 12 that contact the bead seat portion 21 and the rim flange 22 of the rim 20, and the tire from the bead portion 12. A tire skeleton member 17 having a side portion 14 that extends radially outward, and a crown portion 16 that connects a tire radial outer end of one side portion 14 and a tire radial outer end of the other side portion 14 is provided. ing.

  The tire frame member 17 is annular and is formed of a resin material. As the resin material, a thermoplastic resin having rubber-like elasticity, a thermoplastic elastomer (TPE), a thermosetting resin, or the like can be used. In this embodiment, the case where the tire frame member 17 is formed of a thermoplastic material that is one of resin materials will be described.

  The tire frame member 17 has an annular tire frame member half body 17A having the same shape in which one bead portion 12, one side portion 14, and a half-width crown portion 16 are integrally formed by molding or the like. It is formed by joining at the tire equator part. The tire frame member 17 is not limited to a member formed by joining two members, but may be formed by joining three or more members, a pair of bead portions 12, a pair of side portions 14, The crown portion 16 may be integrally formed. Further, a reinforcing material (polymer material, metal fiber, cord, non-woven fabric, woven fabric, etc.) is embedded in the tire frame member 17 (for example, the bead portion 12, the side portion 14, the crown portion 16 and the like) and reinforced. The tire frame member 17 may be reinforced with a material.

  The tire frame member half body 17A made of a thermoplastic material can be molded by, for example, vacuum molding, pressure molding, injection molding, melt casting, etc., and is a manufacturing process compared to molding (vulcanization) with rubber. Can be greatly simplified, and the molding time can be shortened.

  In the present embodiment, the tire frame member half body 17A has a bilaterally symmetric shape, that is, one tire frame member half body 17A and the other tire frame member half body 17A have the same shape. There is also an advantage that only one type of mold for molding the half body 17A is required.

  Even if the tire frame member 17 is made of a single thermoplastic material, each portion of the tire frame member 17 (side portion 14, crown portion 16) is similar to a conventional general rubber pneumatic tire. A thermoplastic material having different characteristics may be used for the bead portion 12 and the like.

  As the thermoplastic material, a thermoplastic resin, a thermoplastic elastomer (TPE), or the like can be used. It is preferable to use a thermoplastic elastomer in consideration of elasticity required during traveling, moldability during production, and the like.

  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 urethane-based thermoplastic elastomer (TPU), crosslinked thermoplastic rubber (TPV), and other thermoplastic elastomers (TPZ).

  Examples of the thermoplastic resin include urethane resin, olefin resin, vinyl chloride resin, polyamide resin, and the like.

In addition, as the thermoplastic material, for example, the deflection temperature under load specified at ISO 75-2 or ASTM D648 (at the time of 0.45 MPa load) is 78 ° C. or higher, and the tensile yield strength specified by JIS K7113 is 10 MPa. As described above, the tensile elongation at break (JIS K7113) stipulated in JIS K7113 is 50% or more. What has Vicat softening temperature (A method) prescribed | regulated to JISK7206 of 130 degreeC can be used.
Moreover, when forming the tire frame member 17 with a thermosetting resin, a phenol resin, a urea resin, a melamine resin, an epoxy resin, a polyester resin, or the like can be used.

  An annular bead core 18 made of a steel cord is embedded in the bead portion 12 of the tire frame member 17, similar to a conventional general pneumatic tire. Note that the bead core 18 may be omitted if the rigidity of the bead portion 12 is ensured and there is no problem in fitting with the rim 20. The bead core 18 may be formed of a cord other than steel, such as an organic fiber cord or a cord coated with an organic fiber, and the bead core 18 is formed of a hard resin instead of a cord by injection molding or the like. It may be.

  A crown portion reinforcing layer 28 made of a steel cord 26 wound in a spiral shape is embedded in the crown portion 16 of the tire frame member 17. Note that the entire cord 26 may be embedded in the crown portion 16, or a part thereof may be embedded in the crown portion 16. The crown portion reinforcing layer 28 corresponds to a belt disposed on the outer peripheral surface of the carcass of a conventional rubber pneumatic tire.

  A tread rubber layer 30 made of rubber having higher abrasion resistance than the thermoplastic material forming the side portion 14 is disposed on the outer peripheral side of the crown portion reinforcing layer 28. The rubber used for the tread rubber layer 30 is preferably the same type of rubber as that used for conventional rubber pneumatic tires. In addition, you may provide the tread layer which consists of another kind of thermoplastic material which is more excellent in abrasion resistance than the thermoplastic material which forms the side part 14 in an outer peripheral part.

  A chafer 24 is formed on the surface of the bead portion 12 of the tire frame member 17 so as to contact the bead seat portion 21 and the rim flange 22 of the rim 20. The chafer 24 is formed at least on the surface of the bead portion 12 at a position where it abuts on the bead seat portion 21 and the rim flange 22 of the rim 20. When the tire 10 is assembled to the rim 20, the chafer 24 is in close contact with the rim 20. Thus, the gas filling space in the tire 10 is sealed.

  The material for the chafer that forms the chafer 24 is a resin material that has better sealing properties than the material that forms the tire frame member 17. As the resin material, a thermoplastic resin having rubber-like elasticity, a thermoplastic elastomer (TPE), a thermosetting resin, or the like can be used. The elastic modulus of the chafer 24 is lower than the elastic modulus of the tire frame member 17. Thereby, between the rim | limbs 20 can be sealed appropriately, maintaining the rigidity of the tire frame member 17. FIG.

  The Chafer 24 elastic modulus is preferably 0.5 Mpa or more and 50 Mpa or less. When the elastic modulus of the chafer 24 is less than 0.5 Mpa, it is conceivable that the compression creep property of the portion that is in close contact with the rim 20 is not sufficient, and a gap is formed between the rim 20 and the chafer 24. This is because when the elastic modulus is more than 50 MPa, it is considered that a sufficient amount of compressive deformation of the portion closely contacting the rim 20 cannot be obtained, and a gap is formed between the rim 20 and the rim 20.

  Further, the elastic modulus of the chafer 24 is more preferably 70% or less of the elastic modulus of the tire frame member 17. The elastic modulus of the chafer 24 is more preferably 50% or less of the elastic modulus of the tire frame member 17, and a resin with excellent wear resistance is used as the chafer material constituting the chafer 24. When used, it is more preferably 25% or less.

The thermoplastic material for the chafer 24 is preferably an olefin-based, ester-based, amide-based, or urethane-based TPE, or TPV in which a rubber-based resin is partially kneaded. As the thermoplastic material for these chafers 24, 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 more, and the tensile yield elongation is also specified by JIS K7113. Is preferably 10% or more, the tensile elongation at break defined by JIS K7113 is 50% or more, and the Vicat softening temperature (Method A) defined by JIS K7113 is 130 ° C. or more.
In addition, as the thermosetting resin for the chafer 24, phenol resin, urea resin, melamine resin, epoxy resin, polyester resin, or the like can be used.

  Next, a method for manufacturing the tire 10 according to the present embodiment will be described. In this embodiment, the tire frame member half body 17A (see FIGS. 2 to 5) is formed by injection molding, and then the chafer material is injection molded to the tire frame member half body 17A to manufacture the chafer 24. Then, the two tire frame member halves 17A face each other and are joined at the tire center. Here, the chafer 24 formed of a thermoplastic material will be described as an example.

  A mold 40 as shown in FIG. 2 is used for manufacturing the tire frame member half body 17A. The mold 40 is an outer mold for molding the tire outer surface side so that the tire frame member half body 17A constituting the bead portion 12 (see FIG. 3) to the tire center CL (see FIG. 3) can be molded. It has the type | mold 42 and the inner metal mold | die 44 which shape | molds the tire inner surface side. The inner mold 44 is provided with a bead core fixing jig 46 at a preset position. Between the outer mold 42 and the inner mold 44, a tire frame member-shaped cavity S (space) is formed.

  The jig 46 is formed with a recess 47 corresponding to the dimensions of the bead core 18. When the bead core 18 is placed in the mold 40, a part of the bead core 18 enters the recess 47 and is supported from the inside of the tire. It will be in the state. As a result, the bead core 18 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. In this embodiment, twelve jigs 46 are arranged at equal intervals along the bead core housing position.

  The jig 46 is formed of a magnet material, and when the bead core 18 is formed of a magnetic material such as steel, the jig 46 can be securely fixed by being adhered by a magnetic force.

  As shown in FIG. 3, the contact length L of the jig 46 to the bead core 18 in the tire circumferential direction, that is, the region A formed on the tire inner side of the tire frame member half body 17 </ b> A where no thermoplastic material is present. The length L along the tire circumferential direction is preferably 20 mm or less. As a result, it is possible to reduce the concern about the generation of the fracture nucleus.

  If the contact length L of the jig 46 to the bead core 18 in the tire circumferential direction is 15 mm or less, stress concentration is less likely to occur in the tire frame member half body 17A. And when this length L is 5 mm or less, it is easier to obtain this effect. The contact length L is preferably at least 1 mm or more from the viewpoint of the strength of the jig 46.

  The gate (resin injection path) 48 of the mold 40 is formed so that the molten thermoplastic polymer material passes through the outside of the tire of the bead core 18 in a state where the bead core 18 enters the recess 47. The thermoplastic polymer material is, for example, a thermoplastic elastomer (TPE) or a thermoplastic resin.

  The gate 48 is a disc gate opened in a ring shape, and the cavity S is formed so as to communicate with the ring-shaped gate 48 and spread in a hollow disk shape. The gate 48 may be a pin gate, but a disk gate is preferable in this way from the viewpoint of formability.

  In the present embodiment, first, the mold 40 is opened, the tire inner side portion of the bead core 18 is put into the concave portion 47 of the jig 46, and the mold 40 is closed. Then, the molten thermoplastic material from the gate 48 is injected into the mold 40 and injection molded to form a tire frame member half body 17A as shown in FIGS. 4 (A) and 4 (B).

  At the time of injection, the thermoplastic material is injected from the gate 48 so as to pass between the bead core 18 and the outer mold 42 at the position where the jig 46 is provided. Is pressed toward. Accordingly, the moving force received by the bead core 18 can be sufficiently supported by the jig 46. Therefore, it is possible to inject the molten thermoplastic material in a state where the jig 46 for preventing displacement of the bead core 18 is not brought into contact with the bead core 18 from the outside of the tire.

  Next, the chafer 24 is formed on the surface of the bead portion 12 of the tire frame member 17 manufactured as described above. For manufacturing the chafer 24, a chafer forming mold 70 as shown in FIG. 5 is used.

  The chafer forming mold 70 includes an outer mold 72, a chafer part mold 73, and an inner mold 74, and a gate 78 for injecting a chafer material into the chafer part mold 73. Is formed. The gate 78 is configured to inject a chafer material from the inside in the tire radial direction of the bead portion 12 of the tire frame member half body 17A. As the gate 78, multiple pin gates may be provided in the circumferential direction of the tire frame member half body 17A, or a disk gate opened in a ring shape may be used.

  A concave portion 72A is formed at a portion where the outer mold 72 is separated from the inner die 74, and a convex portion 74A is formed at a portion where the inner die 74 is separated from the outer die 72. The outer mold 72 and the inner mold 74 are closed by inserting the convex portion 74A into the concave portion 72A.

  A convex portion 73A is formed at a portion where the chafer portion mold 73 is separated from the inner die 74, and a concave portion 74B is formed at a portion where the inner die 74 is separated from the chafer portion die 73. . The chafer part mold 73 and the inner mold 74 are closed by inserting the convex part 73A into the concave part 74B.

  When the tire frame member half body 17A is accommodated in the chafer forming mold 70 and completely closed, as shown in FIG. 9, the gate 78 is interposed between the chafer portion mold 73 and the tire frame member half body 17A. A space Z1 for forming the chafer 24 having a set shape in communication is formed.

  The chafer forming mold 70 is formed with a vent hole (not shown) for expelling air in the cavity when the material for the chafer is injected into the cavity.

  In order to form the chafer 24, first, as shown in FIG. 6, the tire frame member half body 17 </ b> A is set in the inner mold 74. Next, as shown in FIG. 8, the convex portion 74 </ b> A of the inner die 74 is fitted into the concave portion 72 </ b> A of the outer die 72, and the inner die 74 and the outer die 72 are closed. Then, the convex portion 73A of the chafer part mold 73 is engaged with the concave part 74B of the inner mold 74, and the gap M is formed between the chafer part mold 73 and the inner mold 74 dividing surface. Deploy. The gap M is set to about 0.1 mm to 4.0 mm. That is, the space between the chafer part mold 73 and the inner mold 74 of the chafer forming mold 70 is not closed, and the cavity C 1 is formed in the chafer forming mold 70.

  In this state, as shown in FIG. 8, a chafer material is injected from the gate 78 into the cavity C1. At this time, since the material for the chafer is injected along the cavity C1, the movement of the bead portion 12 floating from the inner mold 74 can be suppressed during the injection.

  After the injection of a predetermined amount of chafer material, the chafer part mold 73 and the inner mold 74 are brought into contact with each other to bring the chafer forming mold 70 into a completely closed state. As a result, as shown in FIG. 9, the cavity C1 is reduced to a space Z1, the chafer material is compressed, and the chafer 24 is formed. Thereafter, as shown in FIG. 10, the tire frame member half body 17 </ b> A is taken out from the chafer forming mold 70. Thereby, the tire frame member half body 17A shown in FIG. 11 is formed.

  In this way, after the injection, the chafer forming mold 70 is slightly opened, and the chafer material can be filled into the thin cavity by closing the chafer material after the injection.

  Further, by compressing the chafer material after injection, the molecular orientation of the chafer material is less likely to occur, the residual stress is reduced, and the deformation can be reduced.

  Next, the two tire frame member halves 17A on which the chafer 24 is formed are abutted against each other at the tire center, and the welding thermoplastic material 19 (see FIG. 1) is extruded toward the joining portion. The two tire frame member halves 17A are joined. Thereby, the tire frame member 17 (see FIG. 1) in which the chafer 24 is formed in the bead portion 12 is manufactured.

  In this embodiment, the two tire frame member halves 17A are joined after the chafer 24 is formed, but the two tire skeleton member halves 17A are joined first, and then the chafer 24 is formed. May be.

  Thereafter, while the tire frame member 17 is rotated by the rotating device, the heated cord 26 discharged from the cord supply device (not shown) is spirally wound around the outer peripheral surface of the tire frame member 17 and the crown portion reinforcing layer 28 is wound. Form. In order to wind the cord 26 around the outer peripheral surface of the tire frame member 17 in a spiral manner, the cord supply device may be moved in the axial direction of the tire frame member 17 while rotating the tire frame member 17.

  In addition, the cord 26 is heated to a temperature higher than the melting point of the thermoplastic material constituting the tire frame member 17 (for example, the temperature of the cord 26 is heated to about 100 to 200 ° C.). The thermoplastic material is melted, and a part or the whole of the cord 26 can be embedded in the outer peripheral surface of the tire frame member 17. The amount of the cord 26 embedded can be adjusted by the temperature of the cord 26, the tension applied to the cord 26, and the like.

  Thereafter, a rubber material (tread rubber 30; see FIG. 1) is attached to a portion in contact with the road surface, and the tire 10 with improved wear resistance and fracture resistance is manufactured.

  As described above, in the present embodiment, the chafer 24 having a lower elastic modulus than the tire frame member 17 is formed on the surface of the bead portion 12 of the tire frame member 17 made of a resin material. Therefore, while maintaining the rigidity of the tire frame member 17, the chafer 24 can be brought into close contact with the rim to make it difficult for air in the gas-filled space to escape, and the internal pressure retention of the tire 10 can be improved.

  In order to increase the bonding strength between the surface of the bead portion 12 of the tire frame member half body 17A and the chafer 24, the surface of the bead portion 12 is formed into an uneven shape so that the anchor effect (the anchor is firmly engaged as the anchor is lowered). Effect) may be obtained.

  For example, as shown in FIG. 12A, a bead portion constituting portion 12M in which inverted frustoconical convex portions 12X having a larger diameter on the chafer side than on the root side may be arranged. As shown in FIG. 12 (B), the bead portion constituting portion 12M having a concavo-convex shape 12Y on the chafer side can be used as the bead portion having a concave sectional shape 12Z on the chafer side as shown in FIG. 12 (C). An anchor effect is also obtained as the component 12M.

  The depth of the unevenness for obtaining such an anchor effect is preferably 2 mm or less, and more preferably 1 mm or less. If it is deeper than 2 mm, the strength of the molded product may be reduced. Further, if the depth of the unevenness is shallower than 0.05 mm, it is difficult to obtain a sufficient anchor effect.

  In order to form such an uneven shape, an uneven shape corresponding to the molding surface of the mold 40 may be formed in advance.

  Further, in order to increase the bonding strength between the surface of the bead portion 12 of the tire frame member half body 17A and the chafer 24, one or two layers are formed on the surface of the tire frame member half body 17A where the chafer 24 is formed. An adhesive layer may be applied. In this case, if the surface of the part to which the adhesive is applied is buffed with sandpaper or the like, the adhesive force is improved. Moreover, in order to improve adhesive force, it is preferable to dry to some extent after apply | coating an adhesive agent. For this reason, when apply | coating an adhesive agent, it is preferable to carry out in the atmosphere of 70% or less of humidity. The adhesive is, for example, a triazine thiol adhesive, but is not particularly limited, such as a chlorinated rubber adhesive, a phenol resin adhesive, an isocyanate adhesive, and a halogenated rubber adhesive.

[Second Embodiment]
Next, a second embodiment will be described. In the present embodiment, the same parts as those in the first embodiment are denoted by the same reference numerals, and detailed description thereof is omitted. The tire 90 of the present embodiment is different from the first embodiment only in the chafer configuration, and the other configurations are the same as those in the first embodiment.

  As shown in FIG. 13, the chafer 80 of the present embodiment extends to the inside of the tire (the tire inner surface) inside the bead portion 12 and extends to the side portion 14 outside the bead portion 12.

  By extending the chafer 80 to the inside of the tire of the bead portion 12 (the tire inner surface), the edge of the chafer 80 at the time of assembling the rim compared to the case where the chafer 24 is provided only on the outer side of the tire of the bead portion 12. Turn over curling.

Further, by extending the chafer 80 to the side portion 14 outside the bead portion 12, the side portion 14 of the tire 10 can be prevented from being damaged by a curbstone or the like. The chafer 80 may extend near the tread or inside the tread.
The thickness of the portion corresponding to the side portion 14 of the chafer 80 is preferably 0.2 mm or greater and 4.0 mm or less. This is because if it is less than 0.2 mm, the protective effect against damage to the tire frame due to curb rubbing or the like is small, and if it exceeds 2.0 mm, the tire weight increases.

  In addition, about the elasticity modulus and material of the chafer 80, the thing similar to the chafer 24 of 1st Embodiment can be used.

  Next, a method for manufacturing the tire 90 according to this embodiment will be described. In the present embodiment, as in the first embodiment, the tire frame member half body 17A is formed by injection molding, and then the chafer material is injection molded to the tire frame member half body 17A to manufacture the chafer 80. Then, the two tire frame member halves 17A face each other and are joined at the tire center.

For manufacturing the chafer 24, a chafer forming mold 90 as shown in FIG. 14 is used.
The chafer forming mold 90 includes an outer mold 92, a chafer part mold 93, and an inner mold 94, and a gate 98 for injecting a chafer material into the chafer part mold 93. Is formed. The gate 98 is configured to inject a chafer material from the inner side in the tire radial direction of the bead portion 12 of the tire frame member half body 17A. As the gate 98, multiple pin gates may be provided in the circumferential direction of the tire frame member half body 17A, or a disk gate opened in a ring shape may be used.

  A concave portion 92A is formed at a portion where the outer die 92 is separated from the inner die 94, and a convex portion 94A is formed at a portion where the inner die 94 is separated from the outer die 92. The outer mold 92 and the inner mold 94 are closed by inserting the convex portion 94A into the concave portion 92A.

  A convex portion 93A is formed at a portion where the chafer portion mold 93 is separated from the inner die 94, and a concave portion 94B is formed at a portion where the inner die 94 is separated from the chafer portion die 93. . The chafer part mold 93 and the inner mold 94 are closed by inserting the convex part 93A into the concave part 94B.

  When the tire frame member half body 17A is accommodated in the chafer forming mold 90 and completely closed, as shown in FIG. 17, the gate 98 is interposed between the chafer portion mold 93 and the tire frame member half body 17A. A space Z2 for forming a chafer 80 having a set shape in communication is formed in the cavity.

  The chafer forming mold 70 is formed with a vent hole (not shown) for expelling air in the cavity when the material for the chafer is injected into the cavity.

  The chafer forming mold 90 is provided with a pressing jig 96. The pressing jig 96 protrudes from the chafer part mold 93 side to the space Z1, and can press the bead part 12 of the tire frame member half body 17A to the inner mold 94. Further, the pressing jig 96 is movable so as to be retracted from the space Z <b> 1 and accommodated in the chafer part mold 93. The pressing jig 96 has a pin shape, and is provided at a plurality of locations at predetermined intervals along the circumferential direction of the chafer part mold 93.

  In order to form the chafer 80, first, as shown in FIG. 14, the tire frame member half body 17 </ b> A is set in the inner mold 94. Next, as shown in FIG. 15, the convex portion 94 </ b> A of the inner die 94 is fitted into the concave portion 92 </ b> A of the outer die 92 to close the inner die 94 and the outer die 92. Then, the convex portion 93 A of the chafer part mold 93 is engaged with the concave part 94 B of the inner mold 94, and a gap M is formed between the chafer part mold 93 and the inner mold 94. Deploy. That is, the space between the chafer part mold 93 and the inner mold 94 of the chafer forming mold 90 is not closed, and the cavity C2 is formed in the chafer forming mold 90. Then, the bead portion 12 of the tire frame member half body 17 </ b> A is pressed toward the inner mold 94 with the pressing jig 96.

  In this state, as shown in FIG. 16, a chafer material is injected from the gate 98 into the cavity C2. At this time, since the bead portion 12 of the tire frame member half body 17A is pressed against the inner mold 94 by the pressing jig 96, the movement of the bead portion 12 floating from the inner mold 94 can be suppressed.

  After injecting a predetermined amount of the chafer material, the pressing jig 96 is retracted into the chafer part mold 93 as shown in FIG. Then, the chafer part mold 93 and the inner mold 94 are brought into contact with each other to bring the chafer forming mold 90 into a completely closed state. As a result, as shown in FIG. 17, the cavity C2 is reduced to a space Z2, the chafer material is compressed, and the chafer 80 is formed. Thereafter, as shown in FIG. 18, the tire frame member half body 17 </ b> A is taken out from the chafer forming mold 90. Thereby, the tire frame member half body 17A shown in FIG. 19 is formed.

  In this way, after the injection, the chafer forming mold 90 is slightly opened, and the chafer material can be filled into the thin cavity by closing after injecting the chafer material.

  Further, by compressing the chafer material after injection, the molecular orientation of the chafer material is less likely to occur, the residual stress is reduced, and the deformation can be reduced.

  Furthermore, since the bead part 12 of the tire frame member half body 17A is pressed against the inner mold 94 using the pressing jig 96, the movement of the bead part 12 floating from the inner mold 94 can be suppressed.

  Also, after the pressing jig 96 is retracted, the chafer forming mold 90 is closed and the chafer material is compressed, so that the portion where the pressing jig 96 is disposed is also filled with the chafer material. Can be made.

  The embodiments of the present invention have been described above with reference to the embodiments. However, these embodiments are merely examples, and various modifications can be made without departing from the scope of the invention, and the order of the manufacturing steps can be changed as appropriate. Is possible. It goes without saying that the scope of rights of the present invention is not limited to these embodiments.

DESCRIPTION OF SYMBOLS 10 Tire 12 Bead part 14 Side part 17 Tire frame member 17A Tire frame member half 18 Bead core 20 Rim 21 Bead seat part 22 Rim flange 24 Chafer 70 Chafer formation mold 80 Chafer 90 Tire 90 Chafer formation metal Type 96 Pressing jig

Claims (8)

A tire frame member made of a resin material and having at least a bead portion;
A chafer made of a resin material provided at an adhesion portion of at least the bead portion of the tire frame member and having a lower elastic modulus than the tire frame member;
With tires.   The tire according to claim 1, wherein an elastic modulus of the chafer is 0.5 Mpa or more and 50 Mpa or less.   The tire according to claim 1, wherein the chafer extends to a side portion.   The tire according to claim 3, wherein a thickness of a portion corresponding to the side portion of the chafer is 0.2 mm or more and 4.0 mm or less.   The tire according to any one of claims 1 to 4, wherein the chafer extends to the inside of the gas filling space of the bead portion. It is a manufacturing method of the tire given in any 1 paragraph of Claims 1-5,
A tire skeleton member made of a resin material and forming at least a bead portion is formed.
The cavity in the chafer forming mold accommodates at least the bead portion of the tire frame member, and the dividing surface of the chafer forming mold is not closed, and the elastic modulus is lower than that of the tire frame member. Injecting a chafer material made of a resin material into the mold for forming the chafer,
A tire manufacturing method in which a chafer is formed by completely closing the chafer forming mold and compressing the injected chafer material. When the bead part is accommodated in the chafer forming mold, a holding jig is disposed in the cavity in the chafer forming mold so as to be in contact with the bead part and hold the position of the bead part. thing,
The method for manufacturing a tire according to claim 6. After the injection of the material for the chafer, and before the mold for forming the chafer is completely closed, the holding jig is moved out of the cavity,
The tire manufacturing method according to claim 7.

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