WO2019235328A1

WO2019235328A1 - Pneumatic tire and manufacturing method for pneumatic tire

Info

Publication number: WO2019235328A1
Application number: PCT/JP2019/021350
Authority: WO
Inventors: 圭一長谷川; 誓志今
Original assignee: 株式会社ブリヂストン
Priority date: 2018-06-08
Filing date: 2019-05-29
Publication date: 2019-12-12
Also published as: JP2019209950A

Abstract

In a tire case of this pneumatic tire, a tire width direction outside section of a carcass is covered by a side rubber layer, and a tread is positioned on the tire radius direction outside of the tire case. Additionally, a single-layer belt is provided between the tire case and the tread. This tread is formed with a reinforcement cord embedded in a resin layer, said reinforcement cord being helically wound in the tire circumference direction, and said resin layer being formed from a resin with a greater tensile elastic modulus than the side rubber layer and the tread.

Description

Pneumatic tire and method for manufacturing pneumatic tire

The present disclosure relates to a pneumatic tire including a belt configured to include a spirally wound cord and a method for manufacturing the same.

Japanese Unexamined Patent Publication No. 2013-244930 and Japanese Unexamined Patent Publication No. 2013-220741 disclose a pneumatic tire to be mounted on an automobile. These pneumatic tires are arranged on the outer side in the tire radial direction of the carcass with two or more inclined belt plies configured to include a cord inclined with respect to the tire circumferential direction, and on the outer side in the tire radial direction of the inclined belt ply. A belt composed of a plurality of layers including a reinforcing layer is provided.

By the way, since the pneumatic tire described above includes two or more inclined belt plies and a reinforcing layer, it is possible to ensure the in-plane shear rigidity and the like necessary for reinforcing the crown portion of the carcass, Since the number of plies and reinforcing layers is large, it is difficult to reduce the weight of the tire.
In recent years, there is an increasing need for weight reduction of pneumatic tires, and a pneumatic tire corresponding to the needs is demanded.

The present disclosure is intended to provide a pneumatic tire and a method for manufacturing the same, in which both the in-plane shear rigidity of the belt is secured and the weight is reduced in consideration of the above facts.

The present disclosure is configured to include a carcass straddling one bead portion to the other bead portion, and at least an outer portion in the tire width direction of the carcass is covered with a first rubber material, and the tire case A tread made of a second rubber material disposed on the outer side in the tire radial direction, and provided between the tire case and the tread, and has a higher tensile elastic modulus than the first rubber material and the second rubber material. A single-layer belt that is embedded in a resin layer made of resin and includes a cord that is spirally wound in the tire circumferential direction.

In the present disclosure, the cord is spirally wound on the outer side in the tire radial direction of the tire case, and the cord is embedded in a resin layer provided between the tire case and the tread. That is, the cord constituting the belt is covered with resin.

Here, the resin layer is made of a first rubber material covering the outer portion of the carcass and a resin having a higher tensile elastic modulus than the second rubber material constituting the tread. For this reason, high in-plane shear rigidity can be obtained as compared with a belt in which rubber is disposed between the cords.

Further, since the belt having the above configuration is a single layer belt, the weight can be reduced as compared with a belt composed of a plurality of layers in which rubber is arranged between the cords.

The pneumatic tire according to the present disclosure has an excellent effect that both in-plane shear rigidity of the belt can be ensured and the weight can be reduced.

It is sectional drawing along the tire rotating shaft which shows the pneumatic tire which concerns on 1st Embodiment. FIG. 2 is an enlarged cross-sectional view showing the vicinity of a shoulder of the pneumatic tire shown in FIG. 1. It is a perspective view which shows the process of winding a reinforcement cord around the inner mold | type of the belt shaping die which concerns on 1st Embodiment. It is sectional drawing of the belt shaping die which concerns on 1st Embodiment. FIG. 4 is a front view of an inner mold of the belt molding die shown in FIG. 3. It is sectional drawing corresponding to FIG. 4 which shows the cross section of the belt shaping die which concerns on 2nd Embodiment. (A), (B) is a perspective view of the inner mold | type of the belt molding die which concerns on other embodiment.

[First Embodiment]
A pneumatic tire 10 according to an embodiment of the present invention will be described with reference to FIGS. 1 and 2.
As shown in FIG. 1, the pneumatic tire 10 of the present embodiment is a so-called radial tire used for a passenger car, for example, and includes a pair of bead portions 20 in which a bead core 12 is embedded, and one bead portion 20 and the other are A carcass 16 composed of a single carcass ply 14 straddles the bead portion 20. FIG. 1 shows the shape of the pneumatic tire 10 in a natural state before air filling.

The carcass ply 14 is formed by coating a plurality of cords (not shown) extending in the radial direction of the pneumatic tire 10 with a coating rubber (not shown). That is, the pneumatic tire 10 of the present embodiment is a so-called radial tire. The material of the cord of the carcass ply 14 is, for example, PET, but may be another conventionally known material.

The end portion in the tire width direction of the carcass ply 14 is folded back from the bead core 12 in the tire radial direction. In the carcass ply 14, a portion extending from one bead core 12 to the other bead core 12 is called a main body portion 14 A, and a portion folded from the bead core 12 is called a folded portion 14 B.

Between the main body part 14A and the turn-up part 14B of the carcass ply 14, a bead filler 18 whose thickness gradually decreases from the bead core 12 toward the outer side in the tire radial direction is disposed. In the pneumatic tire 10, a bead portion 20 is a portion on the inner side in the tire radial direction from the tire radial direction outer end 18 A of the bead filler 18.

An inner liner 22 made of rubber is arranged inside the tire of the carcass 16, and a side rubber layer 24 made of a first rubber material is arranged outside the carcass 16 in the tire width direction.
In this embodiment, the bead core 12, the carcass 16, the bead filler 18, the inner liner 22, and the side rubber layer 24 constitute a tire case 25. In other words, the tire case 25 is a tire frame member that forms the frame of the pneumatic tire 10.

(belt)
As shown in FIG. 1, a belt 26 is disposed on the outer side of the crown portion of the carcass 16, in other words, on the outer side in the tire radial direction of the carcass 16, and the belt 26 is in close contact with the outer peripheral surface of the carcass 16. The belt 26 is formed by embedding a reinforcing cord 30 spirally wound in the tire circumferential direction in a resin layer 32 (see FIG. 2). A method for manufacturing the belt 26 will be described later.

The reinforcement cord 30 of the belt 26 is preferably thicker than the cord of the carcass ply 14 and has a high strength (tensile strength). The reinforcing cord 30 of the belt 26 can be composed of monofilament (single wire) such as metal fiber or organic fiber, or multifilament (twisted wire) obtained by twisting these fibers. The reinforcement cord 30 of the present embodiment is a steel cord made of a magnetic material. As the reinforcing cord 30, for example, a “1 × 5” steel cord having a diameter of 0.225 mm can be used, but a steel cord having another structure that is conventionally known can also be used.

The reinforcing cord 30 may be provided with an adhesive layer that improves adhesiveness with a resin layer 32 described later. For the adhesive layer, it is preferable to use a material that is less permeable to moisture than the resin material constituting the resin layer 32, in other words, a material that hardly absorbs moisture. Examples of the adhesive constituting the adhesive layer include modified olefin resins (modified polyethylene resins, modified polypropylene resins, etc.), polyamide resins, polyurethane resins, polyester resins, modified polyester resins, ethylene-acrylic acid. Examples thereof include those containing one or more thermoplastic resins as a main component (main agent) such as ethyl copolymer and ethylene-vinyl acetate copolymer. Among these, from the viewpoint of adhesion to the metal member and the resin layer, it is composed of a modified olefin resin, a polyester resin, a modified polyester resin, an ethylene-ethyl acrylate copolymer, and an ethylene-vinyl acetate copolymer. A hot melt adhesive containing at least one selected from the group is preferred, and a hot melt adhesive containing at least one selected from a modified olefin resin and a modified polyester resin is more preferred, and among them, an acid-modified olefin resin and a modified A hot melt adhesive containing at least one selected from polyester resins is more preferred, and a hot melt adhesive containing an acid-modified polyester resin is particularly preferred.
In addition, the thickness of the adhesive layer can be set to about 0.05 mm as an example, but may be thinner than 0.05 mm or thicker than 0.05 mm.

2, the resin layer 32 is a resin belt formed in an annular shape, and is disposed outside the crown portion of the carcass 16, in other words, outside the carcass 16 in the tire radial direction. A reinforcing cord 30 that is spirally wound in the tire circumferential direction is embedded in the resin layer 32. Thereby, the reinforcement cord 30 is resin-coated.

In the present embodiment, the reinforcement cords 30 embedded in the resin layer 32 are arranged at substantially equal intervals along the tire axial direction in the tire axial direction cross section of the belt 26 (see FIG. 2).

As the resin constituting the resin layer 32, a resin material having a higher tensile elastic modulus than the rubber constituting the side rubber layer 24 and the second rubber material constituting the tread 36 described later is used. Specifically, an elastic thermoplastic resin, a thermoplastic elastomer (TPE), a thermosetting resin, or the like can be used. In view of elasticity during running and moldability during production, it is desirable to use a thermoplastic elastomer.

As thermoplastic elastomers, polyolefin-based thermoplastic elastomer (TPO), polystyrene-based thermoplastic elastomer (TPS), polyamide-based thermoplastic elastomer (TPA), polyurethane-based thermoplastic elastomer (TPU), polyester-based thermoplastic elastomer (TPC) And dynamic crosslinkable thermoplastic elastomer (TPV).

Also, examples of the thermoplastic resin include polyurethane resin, polyolefin resin, vinyl chloride resin, polyamide resin and the like. Further, as a thermoplastic resin material, for example, a deflection temperature under load (0.45 MPa load) specified in ISO 75-2 or ASTM D648 is 78 ° C or more, and a tensile yield strength specified in JIS K7113 is 10 MPa. As described above, those having a tensile fracture elongation specified by JIS K7113 of 50% or more and a Vicat softening temperature (Method A) specified by JIS K7206 of 130 ° C. or more can be used.

Further, the tensile elastic modulus of the resin constituting the resin layer 32 (specified in JIS K7113: 1995) is preferably 100 MPa or more. Moreover, it is preferable that the upper limit of the tensile elasticity modulus of resin which comprises the resin layer 32 shall be 1000 Mpa or less. The tensile modulus of the resin constituting the resin layer 32 is particularly preferably in the range of 200 to 700 MPa.

As shown in FIG. 2, the thickness t (thickness of the resin layer 32) of the belt 26 of the present embodiment is preferably larger than the diameter of the reinforcing cord 30, in other words, the reinforcing cord 30 is completely The resin layer 32 is preferably embedded. Specifically, when the pneumatic tire 10 is for a passenger car, the thickness dimension t of the belt 26 is preferably set to 0.70 mm or more.

A tread 36 made of a second rubber material is disposed outside the belt 26 in the tire radial direction. Conventionally known materials are used as the second rubber material used for the tread 36. A drainage groove 37 is formed in the tread 36. Also, a conventionally known pattern for the tread 36 is used.

The width BW of the belt 26 measured along the tire axial direction is preferably 75% or more with respect to the contact width TW of the tread 36 measured along the tire axial direction. The upper limit of the width BW of the belt 26 is preferably 110% with respect to the ground contact width TW.

Here, the contact width TW of the tread 36 means that the pneumatic tire 10 is mounted on a standard rim stipulated in JATMA YEAR BOOK (2018 edition, Japan Automobile Tire Association Standard), and is applicable size in JATMA YEAR BOOK. Fills with 100% internal pressure of the air pressure (maximum air pressure) corresponding to the maximum load capacity (internal pressure-load capacity correspondence table) in the ply rating, and the rotation axis is parallel to the horizontal plate in a stationary state. When the mass corresponding to the maximum load capacity is added. When the TRA standard or ETRTO standard is applied at the place of use or manufacturing, the respective standards are followed.

Further, the in-plane shear rigidity of the belt 26 is preferably equal to or higher than that of a belt formed by rubber coating.

(Pneumatic tire manufacturing method)
Next, an example of the manufacturing method of the pneumatic tire 10 of this embodiment is demonstrated.
First, an outer periphery of a known tire molding drum (not shown) is formed from an inner liner 22 made of a rubber material, a bead core 12, a bead filler 18 made of a rubber material, a carcass ply 14 in which a cord is covered with a rubber material, and a side rubber layer 24. An unvulcanized tire case 25 is formed. The manufacturing method so far is the same as the conventional one.

Further, the belt 26 is formed by covering the reinforcing cord 30 with the resin layer 32 in a step of forming the resin layer 32 by injection molding after winding one reinforcing cord 30 in a spiral shape.

Hereinafter, an example of the manufacturing process of the belt 26 will be described with reference to FIGS.
First, the cord supply device 60 is movably disposed in the vicinity of the belt molding die 40.

As shown in FIGS. 3 and 4, the belt molding die 40 includes an inner die 42 formed in a cylindrical shape with a short axial dimension, and an outer die 44 arranged on the radially outer side of the inner die 42. It has. The inner die 42 is fixed to a shaft portion 46 disposed coaxially with the inner die 42, and the shaft portion 46 is coaxially fixed to a rotating shaft (not shown) of a motor (not shown). Thus, when the motor is driven, the inner mold 42 is configured to rotate in the circumferential direction (see arrow A shown in FIG. 3).

As shown in FIGS. 5 (A) and 5 (B), the inner mold 42 has a cylinder block 48 fixed to the shaft portion 46, and the cylinder block 48 is provided radially outward via a link mechanism 50. A plurality of extending cylinder rods 52 are provided at equal intervals in the circumferential direction. A belt support piece 54 whose outer surface has an arcuate curved surface is provided at the tip of the cylinder rod.

The cylinder rod 52 is rotated around the link mechanism 50 by rotating the shaft portion 46 with an operation portion (not shown). Thereby, the cylinder rod 52 can be moved between the protruding position shown in FIG. 5A and the retracted position shown in FIG. When the cylinder rod 52 is disposed at the protruding position, the protruding amount of the cylinder rod 52 in the tire radial direction is the largest. In this state, the belt support pieces 54 adjacent to each other in the tire circumferential direction are in close contact with each other, and the circumscribed circle of the inner mold 42 has the largest diameter (shown in FIGS. 5A and 5B). (See circle Q). On the other hand, when the cylinder rod 52 is disposed at the retracted position, the protruding amount of the cylinder rod 52 in the tire radial direction is smaller than the protruding position, and the outer peripheral portion of the inner die 42 is contracted in the tire radial direction. The cylinder rods 52 can be projected in the same direction in conjunction with each other.

Further, as shown in FIG. 4 (A), the belt support piece 54 is provided with a pair of mating surfaces 54A at both ends in the tire axial direction. A pedestal portion 54B that protrudes outward in the tire radial direction is provided between the pair of mating surfaces 54A. Accordingly, the belt support piece 54 has a substantially hat shape that protrudes outward in the tire radial direction in a cross-sectional view in the tire axial direction.

Further, the pedestal portion 54B is gently curved so as to protrude outward in the tire radial direction in a sectional view in the tire axial direction. The outer peripheral surface of this pedestal portion 54 B is shaped along the outer peripheral surface of the carcass 16.

Further, a plurality of (here, five) cord support portions 56 are provided on the outer peripheral surface (outer in the tire radial direction) of the pedestal portion 54B at substantially equal intervals along the circumferential direction of the pedestal portion 54B (FIG. 5). (See (A)). Each cord support portion 56 is constituted by a plurality of cord support pins 58 arranged at substantially equal intervals along the tire width direction. Each cord support pin 58 is formed in a columnar shape as an example, and extends outward in the tire radial direction from the outer peripheral surface of the base portion 54B. The outer diameter of the cord support pin 58 is substantially the same as the outer diameter of the cross-sectional shape of the reinforcing cord 30. Further, the number of cord support pins 58 provided on one cord support portion 56 matches the number of turns of the reinforcing cord 30 wound around the inner mold 42 in the manufacturing process described later.

Here, each cord support pin 58 is configured by a magnet, and the reinforcement cord 30 that is a magnetic body can be attracted and the reinforcement cord 30 can be disposed at the tip of the cord support pin 58. Thereby, when the reinforcement cord 30 is wound around the inner mold 42, the reinforcement cord 30 is supported by the tip portion of the cord support pin 58.

As shown in FIG. 4A, the outer die 44 can be fitted to the outer side of the inner die 42 in the tire radial direction. In this state, the pair of mating surfaces 54 A of the inner mold 42 is a mating surface with the outer mold 44. When the inner mold 42 and the outer mold 44 are fitted, an annular inner space R is formed. The resin material can be injected into the belt molding die 40 through a flow path (not shown) provided in the outer die 44.

The cord supply device 60 includes a reel 62 around which the reinforcing cord 30 is wound, and sends the reinforcing cord 30 toward the outer peripheral surface of the inner mold 42 while applying a predetermined tension to the reinforcing cord 30 by a guide member (not shown). It is configured.

Next, as shown in FIG. 3, the cylinder rod 52 is arranged at the protruding position, the inner die 42 is rotated in the direction of arrow A, and the reinforcing cord 30 is directed from the cord supply device 60 toward the pedestal portion 54 B of the inner die 42. And send it out. Then, the reinforcement cord 30 is wound in the circumferential direction of the pedestal portion 54B while the reinforcement cord 30 is supported on the cord support pins 58 provided on the outer peripheral surface of the pedestal portion 54B. Accordingly, the reinforcing cord 30 is spirally wound in the circumferential direction of the pedestal portion 54B while being separated from the outer peripheral surface of the pedestal portion 54B.

Next, as shown in FIG. 4A, the inner mold 42 around which the reinforcing cord 30 is wound and the outer mold 44 are fitted, and an annular resin layer 32 is formed by injection molding.

As shown in FIG. 4B, the belt 26 having the cured resin layer 32 is removed from the belt mold 40. First, the outer mold 44 is separated from the inner mold 42 radially outward to release the fitted state. Thereafter, the cylinder rod 52 is disposed at the retracted position, the inner die 42 is contracted in the tire radial direction, and the belt 26 is removed from the inner die 42.

Here, a portion of the resin layer 32 that is injection-molded so as to cover the cord support portion 56 on the outer peripheral surface of the inner mold 42 is pinned by a cord support pin 58 protruding from the outer peripheral surface of the inner mold 42. Is formed (see FIG. 4B). The pin hole 64 extends outward in the tire radial direction from the inner surface in the tire radial direction of the resin layer 32 and reaches the reinforcing cord 30 from the inner side in the tire radial direction. Although not shown, a part of the rubber material (here, coating rubber (not shown) of the carcass 16) covering the outer periphery of the carcass 16 flows into the pin hole 64 in the tire vulcanizing process described later. ing. Thereby, in the site | part in which the pin hole 64 was provided, the contact area (joint area) of the resin layer 32 and the carcass 16 is increased. The rubber material that flows into the pin hole 64 only needs to be flown so as to fill at least a part of the inside of the pin hole 64.

Thereafter, the tire case 17 is expanded and the outer peripheral surface of the tire case 17, in other words, the outer peripheral surface of the carcass 16 is crimped to the inner peripheral surface of the belt 26. Finally, an unvulcanized tread 36 is attached to the outer peripheral surface of the belt 26 in the same manner as a general pneumatic tire, thereby completing a green tire.

The raw tire produced in this way is vulcanized and molded with a vulcanization mold in the same manner as a general pneumatic tire, and the pneumatic tire 10 is completed.

(Function, effect)
Next, functions and effects of the pneumatic tire 10 of the present embodiment will be described.
In the pneumatic tire 10 of the present embodiment, the crown portion of the carcass 16 is reinforced by the belt 26 in which the reinforcing cord 30 wound spirally is embedded in the resin layer 32, so that two or more conventional tires are used. The belt is lighter than a belt composed of a plurality of layers composed of the belt ply. Moreover, since the number of members can be reduced, the manufacture of the pneumatic tire 10 is facilitated.

In the present embodiment, the resin constituting the resin layer 32 is made of a resin material having a higher tensile elastic modulus than that of a cord-coated rubber material applied to a belt composed of a conventional rubber-coated two-layer crossing layer. For this reason, the in-plane shear rigidity of the belt 26 is ensured higher than that of a belt composed of a conventional rubber-coated two-layer crossing layer. Thereby, compared with the belt in which rubber is disposed between the reinforcing cords 30, high in-plane shear rigidity can be obtained. As a result, a lateral force when a slip angle is applied to the pneumatic tire 10 can be sufficiently generated, steering stability can be ensured, and responsiveness can also be improved.

Further, by ensuring the out-of-plane bending rigidity of the belt 26, when a large lateral force is input to the pneumatic tire 10, the buckling of the tread 36 (the surface of the tread 36 undulates and a part thereof is separated from the road surface). Phenomenon).

In this embodiment, a pin hole 64 extending outward in the tire radial direction is formed on the inner surface in the tire radial direction of the resin layer 32 of the belt 26, and the carcass 16 is covered inside the pin hole 64. The rubber material to be inflowed. Thereby, the contact area of the resin layer 32 and the carcass 16, in other words, the junction area by joining can be increased. As a result, for example, the bonding strength between the belt 26 and the carcass 16 can be increased as compared with the case where the inner surface in the tire radial direction of the resin layer 32 is formed flat.

Further, in the manufacturing method of the belt 26 of the present embodiment, after the reinforcing cord 30 of the belt 26 is spirally wound in the circumferential direction of the inner die 42 while being separated from the outer peripheral surface of the inner die 42, The resin layer 32 is formed by injection molding using a belt molding die 40 in which an outer die 44 is fitted to a die 42. For this reason, for example, the side surfaces of the resin-coated cords adjacent to each other in the tire axial direction are compared with the case where a belt is formed by spirally winding a cord previously coated with resin in the circumferential direction of a cylindrical mold. This eliminates the need for a step of joining the belt 26, and the productivity of the belt 26 is greatly improved.

Further, in the present embodiment, since the belt 26 has a single layer structure, the thickness of the belt 26 can be reduced and the thickness of the tread 36 is increased as compared with the case where the belt 26 is configured by two or more conventional belt plies. In addition, the depth of the groove 37 can be increased. Thereby, the lifetime of the pneumatic tire 10 can be extended.

Further, the belt 26 in the pneumatic tire 10 has a reinforcing cord 30 spirally wound, and there is no portion where the reinforcing cord 30 overlaps in the tire radial direction on the circumference, and the thickness is uniform in the tire circumferential direction. Therefore, the pneumatic tire 10 is excellent in uniformity.

[Second Embodiment]
Next, a pneumatic tire 70 and a method for manufacturing the pneumatic tire 70 according to the second embodiment of the present invention will be described. In addition, the same code | symbol is attached | subjected to the same structure as 1st Embodiment, and the description is abbreviate | omitted.
As shown in FIG. 6A, in the method for manufacturing the pneumatic tire 70 of the present embodiment, the configuration of the belt molding die 72 is different from that of the first embodiment. Specifically, the belt molding die 72 includes an inner die 42 and an outer die 44, and is provided with a cord support pin 74 that extends inward in the tire radial direction from the inner surface of the outer die 44. The cord support pin 74 is disposed to face the cord support pin 58 provided on the outer peripheral surface of the inner mold 42 (pedestal portion 54B). For this reason, inside the belt molding die 72, the reinforcing cord 30 is supported from both sides in the tire radial direction. Note that the material, shape, and the like constituting the cord support pin 74 are the same as those of the cord support pin 58 formed on the inner mold 42, and therefore description thereof is omitted.

As shown in FIG. 6B, in the belt 76 formed of the belt molding die 72 having the above-described configuration, the resin layer 32 is injected so as to cover the cord support portion 56 on the outer peripheral surface of the inner die 42. A pin hole 64 is formed by cord support pins 58 and 74 protruding from the outer peripheral surface of the inner die 42 and the inner surface of the outer die 44 in the molded portion. That is, in the said part, the pin hole 64 is formed in the direction which mutually approaches in a tire radial direction from the tire radial direction inner side surface and the tire radial direction outer side surface of the resin layer 32. A part of the rubber material that covers the outer peripheral portion of the carcass 16 flows into the pin hole 64 formed on the inner surface in the tire radial direction of the resin layer 32, as in the first embodiment. On the other hand, in the step of attaching an unvulcanized tread 36 to the outer peripheral surface of the belt 26 inside the pin hole 64 formed on the outer surface of the resin layer 32 in the tire radial direction, the tread 36 or the tread 36 in the tire radial direction is provided. A rubber material disposed on the lower surface is introduced. Thereby, the contact area (bonding area) between the resin layer 32 and the tread 36 is increased.

In the pneumatic tire 70 including the belt 76, the contact area between the resin layer 32 of the belt 76 and the carcass 16 and the tread 36, in other words, the bonding area by bonding can be increased. As a result, the joining strength between the belt 76 and the carcass 16 and the tread 36 can be further increased.

In the manufacturing process of the belt 76, the cord support pins 58 and 74 are provided on the inner die 42 and the outer die 44 of the belt molding die 72, respectively, and the reinforcing cord 30 is arranged in the tire radial direction inside the belt molding die 72. Support from both sides. Thereby, the supporting force of the reinforcement cord 30 inside the belt molding die 72 is improved, and variation in the position of the reinforcement cord 30 at the time of injection molding of the resin layer can be suppressed.

[Other Embodiments]
Although one embodiment of the present invention has been described above, the present disclosure is not limited to the above.

For example, the

belts

26 and 76 of the first embodiment and the second embodiment were formed with a constant diameter and a constant thickness in the tire axial direction, in other words, straight when viewed in a cross section along the tire axis. However, the present invention is not limited to this, and when the outer diameter at the center in the tire width direction is larger than the outer diameter at both ends in the tire width direction, when viewed in a cross section along the tire axis, The arc may be convex outward in the tire radial direction.

In the first embodiment and the second embodiment, the

cord supporting pins

58 and 74 support (place) one reinforcing cord 30. However, the

cord supporting pins

58 and 74 have two cords. It is good also as a structure in which the above reinforcement cord is supported. In addition, the reinforcing cord 30 is configured to be arranged uniformly along the tire axial direction in the sectional view of the

belts

26 and 76 in the tire axial direction. However, the configuration is not limited thereto, and the in-plane shear rigidity of the

belts

26 and 76 is increased. In a desired part, the distance between adjacent reinforcing cords 30 may be set smaller than in other parts.

In the first and second embodiments, the cord support pins 58 and 74 are made of magnets. However, the present invention is not limited to this, and the cord support pins may be made of a nonmagnetic material. In this case, it is good also as a structure which provides the notch part etc. which can mount the reinforcement cord 30 in the front-end | tip part of a cord support pin, and is supported by the cord support pin.

Further, in the first embodiment, the cord support portion 56 of the inner mold 42 is configured by a plurality of the cord support pins 58 arranged along the tire width direction on the outer peripheral surface of the inner mold 42. Not limited to this. A cord support pin 58 may be provided on a line inclined with respect to the tire circumferential direction on the outer peripheral surface of the inner die 42 as in the cord support portion 80 shown in FIG. Alternatively, as in the cord support portion 90 shown in FIG. 7B, the cord support pin 58 is disposed from the substantially central portion in the tire width direction on the outer peripheral surface of the inner mold 42 to one end portion in the tire width direction. It is good also as a structure which alternately provides the site | part in which the code | cord support pin 58 is arrange | positioned from the substantially center part of the tire width direction of the outer peripheral surface of the inner mold 42 to the other end part along the tire width direction.

The disclosure of Japanese Patent Application No. 2018-110644 filed on June 8, 2018 is incorporated herein by reference in its entirety.
All documents, patent applications, and technical standards mentioned in this specification are to the same extent as if each individual document, patent application, and technical standard were specifically and individually described to be incorporated by reference, Incorporated herein by reference.

Claims

A tire case including a carcass straddling one bead portion to the other bead portion, and at least an outer portion in the tire width direction of the carcass is covered with a first rubber material;
A tread made of a second rubber material and disposed on the outer side in the tire radial direction of the tire case;
It is provided between the tire case and the tread and embedded in a resin layer made of a resin having a higher tensile elastic modulus than the first rubber material and the second rubber material, and in the tire circumferential direction. A single-layer belt configured to include a spirally wound cord;
Pneumatic tire having
The resin layer has a plurality of pin holes extending outward in the tire radial direction from the inner surface in the tire radial direction to reach the cord, and a rubber material that covers the carcass flows into the pin holes. The pneumatic tire according to claim 1.
A pneumatic tire manufacturing method for manufacturing the pneumatic tire according to claim 1 or 2,
The cord is spirally formed in the circumferential direction of the inner mold in a state of being separated from the outer circumferential surface of the inner mold by supporting the cord with a plurality of cord support pins provided on the radially outer side of the cylindrical inner mold. After that, the outer mold is fitted on the radially outer side of the inner mold around which the cord is wound, and a resin is injected into the mold constituted by the inner mold and the outer mold. Forming a belt;
Arranging the belt on the outer side in the tire radial direction of the tire case, expanding the tire case, and crimping the outer peripheral surface of the tire case to the inner peripheral surface of the belt;
The manufacturing method of the pneumatic tire comprised including.