JP6930943B2 - Pneumatic tires - Google Patents

Description

The present invention relates to a pneumatic tire provided with a belt configured to include a cord layered in the tire radial direction.

Pneumatic tires to be mounted on automobiles include two or more inclined belt plies configured to include a cord inclined with respect to the tire circumferential direction on the outer side of the carcass in the tire radial direction, and on the outer side of the inclined belt ply in the tire radial direction. A structure including a belt composed of a plurality of layers including an arranged reinforcing layer or the like is common (see, for example, Patent Documents 1 and 2).

JP 2013-244930 Japanese Unexamined Patent Publication No. 2013-220741

However, according to the pneumatic tires of Patent Documents 1 and 2, although the in-plane shear rigidity required for the crown portion of the carcass is secured by two or more inclined belt plies and the reinforcing layer, the ply and the reinforcing layer Since the number of layers of the tire increases, it becomes difficult to reduce the weight of the tire. In recent years, there has been an increasing need for weight reduction of pneumatic tires, and it is necessary to reduce the weight while ensuring the strength required for pneumatic tires.

In consideration of the above facts, an object of the present invention is to provide a pneumatic tire capable of reducing the weight while ensuring the in-plane shear rigidity of the belt and the rigidity in the tire circumferential direction.

The pneumatic tire according to claim 1 includes a carcass extending from one bead portion to the other bead portion, and at least the outer portion of the carcass in the tire width direction is coated with a first rubber material. Than the case, the tread arranged outside the tire case in the tire radial direction and made of the second rubber material, the first cord, and the first cord arranged inside the tire radial direction of the first cord. A second cord having a small outer diameter and a resin that covers the first cord and the second cord and has a tensile elasticity larger than that of the first rubber material and the second rubber material are included. The resin-coated cord is spirally wound along the outer peripheral surface of the tire case on the outer side in the tire radial direction of the tire case and the inner side in the tire radial direction of the tread, and the adjacent resin in a wound state. It includes a resin belt formed integrally by joining the resins at the end of the covering cord in the tire width direction.

According to the pneumatic tire according to claim 1, the belt is in a state where the resin-coated cord provided with the first cord and the second cord is spirally wound and wound around the outer peripheral surface of the tire case. The resins at the ends of the resin-coated cords adjacent to each other in the tire width direction are joined to form an integral structure. Further, the belt is formed of a first rubber material that covers the outer portion of the carcass and a resin having a higher tensile elastic modulus than the second rubber material that constitutes the tread. As a result, higher in-plane shear rigidity can be ensured as compared with a belt in which a rubber material is arranged between cords.

Further, according to the pneumatic tire according to claim 1, the resin-coated cord constituting the belt has an outer diameter smaller than that of the first cord and the first cord arranged inside in the tire radial direction of the first cord. A second code is provided in multiple layers. Therefore, the outer side in the tire radial direction of the belt on which the tensile load acts in the tire circumferential direction can be supported by the first cord, and the inner side in the tire radial direction of the belt on which the compressive load acts in the tire circumferential direction can be supported by the second cord. Can be done. By arranging the cords in multiple layers along the tire radial direction in this way, it is possible to secure high rigidity in the tire circumferential direction as compared with a belt provided with a single layer cord in the tire radial direction.

Further, according to the pneumatic tire according to claim 1, the belt is formed of a resin-coated cord made of resin. As a result, the weight of the tire can be reduced while ensuring the in-plane shear rigidity of the belt and the rigidity in the tire circumferential direction.

The pneumatic tire according to claim 2 is the pneumatic tire according to claim 1, wherein a plurality of the first cord and the second cord are arranged along the tire width direction.

According to the pneumatic tire according to claim 2, a plurality of first cords and second cords are arranged along the tire width direction. Thereby, the tensile load and the compressive load acting on the belt can be supported by a plurality of cords. As a result, high tire circumferential rigidity can be ensured.

The pneumatic tire according to claim 3 is the pneumatic tire according to claim 1 or 2, wherein the first code is composed of a steel cord, and the second code is more than the first code. It is composed of a steel cord with a small outer diameter.

According to the pneumatic tire according to claim 3, since the second cord is composed of a steel cord having an outer diameter smaller than that of the first cord, the second cord has more bending resistance than the first cord. I'm out. As a result, the belt provided with the second cord can improve the durability against compressive deformation.

The pneumatic tire according to claim 4 is the pneumatic tire according to claim 1 or 2, wherein the first cord is made of a steel cord and the second cord is made of organic fibers. There is.

According to the pneumatic tire according to claim 4, the second cord is composed of organic fibers having higher bending resistance than the first cord. As a result, the belt provided with the second cord can further improve the durability against compressive deformation.

As described above, the pneumatic tire according to claim 1 has an excellent effect that the weight of the tire can be reduced while ensuring the in-plane shear rigidity of the belt and the rigidity in the tire circumferential direction.

The pneumatic tire according to claim 2 has an excellent effect that high tire circumferential rigidity can be ensured because the tensile load and the compressive load in the tire circumferential direction acting on the belt can be supported by a plurality of cords. Has.

The pneumatic tire according to claim 3 has an excellent effect that the durability against compressive deformation can be improved in addition to reducing the stress generated in each cord.

The pneumatic tire according to claim 4 has an excellent effect that the stress generated in each cord can be reduced and the durability against compressive deformation can be further improved.

It is sectional drawing which cut the pneumatic tire which concerns on 1st Embodiment of this invention along the tire width direction. FIG. 5 is an enlarged cross-sectional view of the vicinity of the shoulder of the pneumatic tire according to the first embodiment cut along the tire width direction. It is an enlarged cross-sectional view which cut the vicinity of the shoulder of the pneumatic tire which concerns on 1st modification of 1st Embodiment along the tire width direction. FIG. 5 is an enlarged cross-sectional view of a resin-coated cord having a parallelogram cross-sectional shape according to a second modification of the first embodiment cut along the tire width direction. It is an enlarged cross-sectional view which cut | cut the resin coating cord which the side surface of the end portion in the tire width direction inclined according to the 2nd modification of 1st Embodiment, along the tire width direction. FIG. 5 is an enlarged cross-sectional view of a resin-coated cord having an arcuate side surface of an end portion in the tire width direction according to a second modification of the first embodiment cut along the tire width direction. FIG. 5 is an enlarged cross-sectional view of a resin-coated cord having an inverted S-shaped side surface at an end portion in the tire width direction according to a second modification of the first embodiment, cut along the tire width direction. FIG. 5 is an enlarged cross-sectional view of a resin-coated cord provided with a bonding resin layer on the outer periphery of the cord according to the second modification of the first embodiment, cut along the tire width direction.

(First Embodiment)
The pneumatic tire 10 according to the first embodiment of the present invention will be described with reference to FIGS. 1 and 2.

(Tire skeleton member)
FIG. 1 shows, for example, the shape of a pneumatic tire 10, which is a radial tire used in a passenger car, in a natural state before being filled with air. The pneumatic tire 10 includes a pair of bead portions 20 in which, for example, bead cores 16 formed by winding bead wires (not shown) in multiple layers are embedded on both end sides in the tire width direction. A cross section of a carcass ply 22 as a single carcass cut along the tire width direction between the bead portion 20 on one side in the tire width direction and the bead portion (not shown) on the other side in the tire width direction. When it is, it straddles like a toroid.

The carcass ply 22 is formed by rubber-coating a plurality of cords (not shown) made of organic fibers such as polyester, which extend in the radial direction of the pneumatic tire 10. Although the material of the cord of the carcass ply 22 has been described here as polyester, the material is not limited to this, and other conventionally known materials may be used.

The end portion of the carcass ply 22 in the tire width direction is folded back from the inside to the outside of the bead core 16 in the tire width direction. The carcass ply 22 is viewed from the inside of the bead core 16 on one side in the tire width direction to the inside of the bead core on the other side in the tire width direction in the tire width direction cut along the tire width direction. It is provided with a main body portion 22A straddling a toroid shape and a folded-back portion 22B of the bead core 16 folded outward in the tire width direction.

A bead filler 26 made of hard rubber extending from the outer peripheral surface of the bead core 16 to the outside in the tire radial direction is arranged between the main body portion 22A and the folded-back portion 22B of the carcass ply 22. The bead portion 20 is formed from the tire radial outer end portion 26A of the bead filler 26 of the pneumatic tire 10 to the tire radial inner portion including the bead core 16.

A rubber inner liner 28 is arranged inside the carcass ply 22 in the tire width direction, and a side rubber layer 30 made of a first rubber material is arranged outside the carcass ply 22 in the tire width direction. The tire case 34 as a tire skeleton member forming the skeleton of the pneumatic tire 10 is composed of a bead core 16, a carcass ply 22, a bead filler 26, an inner liner 28, and a side rubber layer 30.

(belt)
As shown in FIG. 2, a belt 40 manufactured by a method described later is arranged on the outer side of the carcass ply 22 in the tire radial direction (outside of the crown portion). The belt 40 is composed of a resin-coated cord 48 wound so as to be in close contact with the outer peripheral surface of the carcass ply 22. The resin-coated cords 48 are a first reinforcing cord 42 as a first cord of a plurality of cords (two in the present embodiment) arranged on the outer side in the tire radial direction, and a plurality of cords (two in the present embodiment) arranged on the inner side in the tire radial direction. The second reinforcing cord 44 as the second cord of (3) is formed by being coated with the resin 46. The first reinforcing cord 42 and the second reinforcing cord 44 are arranged in multiple layers along the tire radial direction. Further, the first reinforcing cord 42 and the second reinforcing cord 44 are respectively arranged inside the resin coating cord 48 so that their centers do not overlap in the tire radial direction.

It is preferable that the first reinforcing cord 42 of the belt 40 is thicker than the cord of the carcass ply 22 and has a large strength (tensile strength). The first reinforcing cord 42 of the belt 40 is composed of a monofilament (single wire) such as a metal fiber or an organic fiber, or a multifilament (twisted wire) obtained by twisting these fibers. Specifically, for example, a "1 x 5" steel cord having a diameter of 0.225 mm is used. Here, the first reinforcing cord 42 has been described as using a “1 × 5” steel cord having a diameter of 0.225 mm, but the present invention is not limited to this, and a steel cord having another conventionally known structure may be used. can.

The second reinforcing cord 44 of the belt 40 is configured to have an outer diameter smaller than that of the first reinforcing cord 42 by a monofilament (single wire) of a metal fiber or a multifilament (twisted wire) obtained by twisting a metal fiber.

For the resin 46 that covers the first reinforcing cord 42 and the second reinforcing cord 44, a resin material having a higher tensile elastic modulus than the rubber constituting the side rubber layer 30 and the second rubber material constituting the tread 50 described later is used. Has been done. As the resin 46 that coats the first reinforcing cord 42 and the second reinforcing cord 44, an elastic thermoplastic resin, a thermoplastic elastomer (TPE), a thermosetting resin, or the like can be used. In particular, it is desirable to use a thermoplastic elastomer in consideration of the elasticity during running and the moldability during manufacturing of the automobile equipped with the pneumatic tire 10.

Examples of the thermoplastic elastomer include polyolefin-based thermoplastic elastomer (TPO), polystyrene-based thermoplastic elastomer (TPS), polyamide-based thermoplastic elastomer (TPA), polyurethane-based thermoplastic elastomer (TPU), and polyester-based thermoplastic elastomer (TPC). , Dynamic cross-linked thermoplastic elastomer (TPV) and the like.

Examples of the thermoplastic resin include polyurethane resin, polyolefin resin, vinyl chloride resin, and polyamide resin. Further, as the thermoplastic resin material, for example, the deflection temperature under load (at 0.45 MPa load) specified in ISO75-2 or ASTM D648 is 78 ° C. or higher, and the tensile yield strength specified in JIS K7113 is 10 MPa. As described above, those having a tensile breakdown elongation of 50% or more specified in JIS K7113 and a Bikat softening temperature (method A) specified in JIS K7206 of 130 ° C. or more can be used.

The tensile elastic modulus (specified in JIS K7113: 1995) of the resin 46 covering the first reinforcing cord 42 and the second reinforcing cord 44 is preferably 50 MPa or more. The upper limit of the tensile elastic modulus of the resin 46 is preferably 1000 MPa or less. Among them, the tensile elastic modulus of the resin 46 is particularly preferably in the range of 200 to 500 MPa.

As shown in FIG. 1, it is preferable that the thickness dimension t of the belt 40 of the present embodiment is larger than the diameter dimension of the first reinforcing cord 42, that is, the first reinforcing cord 42 is completely made of the resin 46. It is preferably buried. When the pneumatic tire 10 is for a passenger car, the thickness dimension t of the belt 40 is preferably 0.70 mm or more.

A tread 50 made of a second rubber material is arranged on the outer side of the belt 40 in the tire radial direction. As the second rubber material used for the tread 50, conventionally known ones are used. A drainage groove 52 is formed in the tread 50. Further, as the pattern of the tread 50, a conventionally known pattern is used. Further, a portion of the tread 50 that is continuous with the tire case 34 on the outer side in the tire width direction is a shoulder 54.

The width BW of the belt 40, which is the length of the belt 40 in the tire axial direction, is preferably 75% or more of the ground contact width TW of the tread 50, which is the length of the tread 50 in the tire axial direction. The upper limit of the width BW of the belt 40 is preferably 110% with respect to the ground contact width TW. Further, the in-plane shear rigidity of the belt 40 is preferably equal to or higher than that of the belt formed of the rubber coating.

Here, the ground contact width TW of the tread 50 means that the pneumatic tire 10 is attached to the standard rim specified in the JATMA YEAR BOOK (2018 version, Japan Automobile Tire Association standard), and the applicable size in the JATMA YEAR BOOK. The internal pressure is 100% of the air pressure (maximum air pressure) corresponding to the maximum load capacity (internal pressure-load capacity correspondence table in bold) in the ply rating, and the rotation axis becomes parallel to the horizontal flat plate in a stationary state. It is the one when the mass corresponding to the maximum load capacity is added. If the TRA standard or ETRTO standard is applied at the place of use or manufacturing, the respective standards will be followed.

(Manufacturing method of pneumatic tires)
An example of the method for manufacturing the pneumatic tire 10 of the present embodiment will be described. First, an unvulcanized tire case 34 including an inner liner 28, a bead core 16, a bead filler 26, a carcass ply 22, and a side rubber layer 30 is formed on the outer periphery of a known tire molding drum (not shown). It is formed. The production up to this point is produced by a known method.

Next, as shown in FIG. 2, the belt 40 is formed by spirally winding a resin-coated cord 48 in which the first reinforcing cord 42 and the second reinforcing cord 44 are coated with the resin 46. .. The cross-sectional shape of the resin coating cord 48 is formed in a substantially rectangular shape (substantially rectangular shape) when viewed in a cross-sectional view cut along the tire width direction. Further, the end portion of the resin coating cord 48 in the tire width direction (shown by a two-dot chain line in FIG. 2) is in contact with the end portion of the adjacent resin coating cord 48 in the tire width direction.

In order to form the belt 40, a supply device (not shown) for supplying the resin-coated cord 48 in the vicinity of a belt forming drum (not shown) for winding the resin-coated cord 48 to form the belt, and belt forming. A heating device (not shown) for heating the resin-coated cord 48 wound around the drum is arranged. Further, in the vicinity of the belt forming drum, a pressing roller for pressing the resin coating cord 48 against the belt forming drum (not shown) and a cooling roller for cooling the welded resin coating cord 48 (not shown) are provided. Be placed.

The surface of the resin 46 is melted by heating the resin coating cord 48 sent out from the supply device by the heating device. The resin-coated cord 48 in which the surface of the resin 46 is melted is wound around the outer peripheral surface of the belt forming drum in a state of being pressed by a pressing roller. The pressed resin coating cord 48 is crushed so that the side portion (end portion in the tire axial direction) bulges in the tire axial direction. The side surfaces of the crushed resin 46 adjacent to each other in the tire axial direction are welded by contacting each other. Since the welded resin 46 is solidified by being brought into contact with the cooling roller, it is solidified in a state where the adjacent resin coating cords 48 are welded to each other. In this way, the resin coating cord 48 is spirally wound around the outer peripheral surface of the belt forming drum and pressed against the outer peripheral surface, so that the belt 40 is formed on the outer peripheral surface of the belt forming drum.

The belt 40 on which the resin 46 is solidified is removed from the belt forming drum and arranged on the radial outer side of the tire case 34 of the tire forming drum. By expanding the tire case 34 with the belt 40 arranged, the outer peripheral surface of the carcass ply 22 which is the outer peripheral surface of the tire case and the inner peripheral surface of the belt 40 are crimped. A raw tire is formed by attaching an unvulcanized tread 50 to the outer peripheral surface of the belt 40 to which the tire case 34 is crimped, in the same manner as a general pneumatic tire.

Next, the operation and effect of this embodiment will be described.

According to the present embodiment, the belt 40 is adjacent to each other in a state in which the resin coating cord 48 in which the first reinforcing cord 42 and the second reinforcing cord 44 are coated with the resin 46 is spirally wound and wound. The resins 46 at the ends of the matching resin coating cords 48 in the tire width direction are joined to each other to form an integral structure. Therefore, the bonding strength of the resin-coated cords 48 adjacent to each other in the belt width direction can be increased. Further, the belt 40 is formed of a resin 46 having a tensile elastic modulus larger than that of the first rubber material covering the outer portion of the carcass ply 22 and the second rubber material constituting the tread 50. From these facts, it is possible to secure high in-plane shear rigidity as compared with the belt in which the rubber material is arranged instead of the resin 46.

Specifically, the belt 40 of the present embodiment has a tensile elastic modulus of 50 MPa or more and a thickness of 0.7 mm or more to sufficiently secure the in-plane shear rigidity of the belt 40 in the tire width direction. Can be done.

Further, according to the present embodiment, the resin-coated cord 48 constituting the belt 40 has a first reinforcing cord 42 on the tire radial outer side (tread side) and a first reinforcing cord 42 on the tire radial inner side (tire case side). A second reinforcing cord 44 having an outer diameter smaller than 42 is provided in multiple layers. Therefore, the outer side in the tire radial direction of the belt on which the tensile load acts in the tire circumferential direction can be supported by the first reinforcing cord 42, and the second reinforcing cord on the inner side in the tire radial direction of the belt on which the compressive load acts in the tire circumferential direction. It can be supported by 44. Further, since the first reinforcing cord 42 and the second reinforcing cord 44 are arranged inside the resin coating cord 48 so that their centers do not overlap in the tire radial direction, the first reinforcing cord 42 and the second reinforcing cord 42 are respectively arranged. The stress generated in 44 can be dispersed in the tire width direction. As a result, it is possible to secure high rigidity in the tire circumferential direction as compared with a belt provided with a cord in a single layer in the tire radial direction.

Here, since the second reinforcing cord 44 is made of a steel cord having an outer diameter smaller than that of the first reinforcing cord 42, the second reinforcing cord 44 is more resistant to bending than the first reinforcing cord 42. As a result, the belt 40 provided with the second reinforcing cord 44 can improve the durability against compressive deformation.

Further, according to the pneumatic tire 10 of the present embodiment, the belt 40 is formed in a single layer in the tire radial direction by the resin coating cord 48. Further, since the resin coating cord 48 is spirally wound and there is no portion that overlaps in the tire radial direction, the belt 40 is formed to have a uniform thickness in the tire circumferential direction. Therefore, the weight is lighter than that of a belt formed in a plurality of layers by two or more belt plies like a conventional tire, and a tire having excellent uniformity can be easily manufactured. Further, by forming the belt 40 in a single layer in the tire radial direction, the thickness of the tread 50 can be increased and the depth of the groove 52 can be increased, so that the life of the pneumatic tire 10 can be extended. It becomes possible.

As described above, the pneumatic tire 10 according to the present embodiment can be reduced in weight while ensuring the in-plane shear rigidity of the belt 40 and the tire circumferential rigidity.

In addition to the above, by ensuring the in-plane shear rigidity of the belt 40, it is possible to sufficiently generate a lateral force when a slip angle is applied to the pneumatic tire 10, so that steering stability is ensured. And the responsiveness can be improved.

Further, in the pneumatic tire 10 according to the present embodiment, since the belt 40 having high in-plane shear rigidity is used, the rigidity in the vicinity of the shoulder 54 that protects the carcass ply 22 can be increased.

Further, as the in-plane shear rigidity of the belt 40 is improved, the out-of-plane bending rigidity of the belt 40 is also improved. Therefore, when a large lateral force is applied to the pneumatic tire 10, the buckling of the tread 50 (a phenomenon in which the surface of the tread 50 undulates and a part of the tread 50 is separated from the road surface) can be suppressed.

(First modification)
Next, the pneumatic tire 60 according to the first modification of the present embodiment will be described with reference to FIG. The same components as those in the above-described embodiment are designated by the same numbers, and the description thereof will be omitted.

According to this modification, the second reinforcing cord 64 provided in the resin-coated cord 68 is made of, for example, a first reinforcing cord by means of a monofilament (single wire) of organic fibers or a multifilament (twisted wire) obtained by twisting organic fibers. It is configured to have an outer diameter smaller than 42.

According to this modification, since the second reinforcing cord 64 is made of organic fibers, it is more flexible than the first reinforcing cord 42 and more durable than the steel cord. Therefore, the belt 40 provided with the second reinforcing cord 64 can further improve the durability against compressive deformation. As a result, the pneumatic tire 60 can secure high rigidity in the tire circumferential direction.

As described above, the pneumatic tire 60 according to the present modification can secure both the in-plane shear rigidity of the belt 62 and the tire circumferential rigidity and reduce the weight.

(Second modification)
Next, the pneumatic tire 70 according to the second modification will be described with reference to FIGS. 4A to 4E. The same components as those of the above-described first embodiment are designated by the same numbers, and the description thereof will be omitted.

According to this modification, the cross-sectional shape of the resin-coated cord 72 cut along the tire width direction is formed in a shape other than a substantially rectangular shape. Specifically, the resin-coated cord 72 shown in FIGS. 4A and 4E has a parallelogram in cross section, and the end portion in the tire width direction is inclined at a constant angle. Further, in the resin-coated cord 72 shown in FIG. 4B, an end portion in the tire width direction is inclined, and a step portion is formed at a substantially intermediate portion in the tire radial direction of the end portion. Further, in the resin coating cord 72 shown in FIGS. 4C and 4D, the end portion in the tire width direction is formed in an arc shape and an inverted S shape.

The resin-coated cords 72 shown in FIGS. 4A to 4E are all formed so that the length of the end portion in the tire width direction is longer than that of the resin-coated cord 48 having a substantially rectangular cross section shown in FIG. There is. Therefore, the bonding area (welding area) between the resin-coated cords 72 adjacent to each other in the belt width direction can be increased as compared with the resin-coated cord 48 having a substantially rectangular cross section shown in FIG. As a result, the joint strength of the resin-coated cord 72 can be increased, so that the pneumatic tire 70 can secure high in-plane shear rigidity.

Further, the resin-coated cord 72 shown in FIG. 4E is arranged on the outer periphery of the first reinforcing cord 42 and the second reinforcing cord 44, and the first reinforcing cord 42 and the second reinforcing cord 44 and the resin 46 are joined (adhered). ) Is provided for the bonding resin layer 90.

The bonding resin layer 90 is formed of a bonding resin material having excellent adhesiveness to the first reinforcing cord 42 and the second reinforcing cord 44. Examples of the bonding resin material include modified olefin resins (modified polyethylene resins, modified polypropylene resins, etc.), polyamide resins, polyurethane resins, polyester resins, ethylene-ethyl acrylate copolymers, and ethylene-acetic acid. Examples thereof include those containing one or more types of thermoplastic resins such as vinyl copolymers as a main component (main agent). Among these, from the viewpoint of adhesion to the first reinforcing cord 42 and the second reinforcing cord 44, from the modified olefin resin, the polyester resin, the ethylene-ethyl acrylate copolymer, and the ethylene-vinyl acetate copolymer. A hot melt adhesive containing at least one selected is preferable, and a modified olefin resin (acid-modified olefin resin) acid-modified with an unsaturated carboxylic acid is more preferable. Here, the "modified olefin resin acid-modified with an unsaturated carboxylic acid" means a modified olefin resin obtained by graft-copolymerizing an unsaturated carboxylic acid with a polyolefin. Further, as these olefin-based thermoplastic elastomers, those having an elastic modulus of 140 MPa to 950 MPa are preferably used.

(Other embodiments)
Although the first embodiment of the present invention and examples of modifications thereof have been described above, the present invention is not limited to the above, and other than the above, various modifications can be made within a range not deviating from the gist thereof. Of course.

Here, it has been explained that the belts 40 and 62 are formed with a constant diameter and a constant thickness in the tire axis direction, that is, are formed in a straight line when viewed in a cross section along the tire axis. However, the belt is not limited to this, when the outer diameter of the central portion in the tire width direction is formed to be larger than the outer diameter of both ends in the tire width direction, and the belt is viewed in a cross section cut along the tire width direction. In addition, the central portion in the tire width direction may be formed in a substantially arc shape in which the central portion in the tire width direction is convex outward in the tire radial direction.

Further, here, the resin coating cords 48, 68, 72 used in manufacturing the belts 40, 62 are those in which a plurality of first reinforcing cords 42 and second reinforcing cords 44, 64 are coated with resin 46. However, the present invention is not limited to this, and the resin-coated cord may be one in which one first reinforcing cord and one second reinforcing cord are coated with resin. Further, three or more first reinforcing cords and four or more second reinforcing cords may be coated with resin.

Further, the pneumatic tires 10, 60, and 70 according to the present embodiment have been described as being general radial tires, but the present invention is not limited to this, and the tires 10, 60, and 70 are used for run-flat tires whose side portions are reinforced with reinforcing rubber. May be good.

Further, the belts 40 and 62 of the present embodiment have been described as having the side surfaces of the resin coating cords 48, 68 and 72 adjacent in the belt width direction joined by welding, but the present invention is not limited to this. It may be joined using an adhesive.

10, 60, 70 ... Pneumatic tires, 20 ... Beads, 22 ... Carcass ply (Carcus), 30 ... Side rubber layer (first rubber material), 34 ... Tire cases, 40, 62 ... Belts, 42 ... First Reinforcement cord (1st cord), 44, 64 ... 2nd reinforcement cord (2nd cord), 46 ... Resin, 48, 68, 72 ... Resin coating cord, 50 ... Tread (second rubber material), BW ... Belt Width, TW ... Grounding width

Claims (4)

A tire case including a carcass straddling from one bead portion to the other bead portion, and at least the outer portion of the carcass in the tire width direction is coated with a first rubber material.
A tread arranged on the outer side of the tire case in the tire radial direction and made of a second rubber material, and a tread.
The first cord, the second cord having an outer diameter smaller than that of the first cord arranged inside the tire radial direction of the first cord, and the first cord and the second cord are covered with the first cord. The tire case has a resin coating cord composed of a rubber material and a resin having a tensile elasticity larger than that of the second rubber material on the outer side of the tire case in the tire radial direction and on the inner side of the tread in the tire radial direction. A resin belt integrally formed by joining the resins at the ends of the adjacent resin-coated cords in the tire width direction in a spirally wound and wound state along the outer peripheral surface of the tire.
Pneumatic tires with. The pneumatic tire according to claim 1, wherein a plurality of the first cord and the second cord are arranged along the tire width direction. The pneumatic tire according to claim 1 or 2, wherein the first cord is composed of a steel cord, and the second cord is composed of a steel cord having an outer diameter smaller than that of the first cord. The pneumatic tire according to claim 1 or 2, wherein the first cord is made of a steel cord, and the second cord is made of an organic fiber.

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