WO2019239941A1 - Pneumatic tire - Google Patents

Abstract

A pneumatic tire according to the present invention comprises: a carcass formed across a pair of bead cores; a resin belt layer disposed on the outer side of the carcass in the tire radial direction and composed of a resin-coated cord formed by coating a cord with resin, the resin-coated cord being wound into a spiral shape in the tire circumferential direction; and a resin protective member fused to a front end surface of the resin-coated cord and extending along the tire circumferential direction.

Description

Pneumatic tire

This disclosure relates to a pneumatic tire.

JP 2012-523340 A discloses a tire in which a circumferential belt is formed of a stainless steel cord or the like parallel to the tire circumferential direction.

On the other hand, in recent years, it is required to use a resin material (for example, a thermoplastic resin, a thermoplastic elastomer, etc.) as a tire material from the viewpoint of weight reduction, ease of molding, and ease of recycling. Japanese Unexamined Patent Application Publication No. 2014-210487 discloses a tire in which a reinforcing cord member is spirally wound around a crown portion of a resin tire frame member.

In a tire in which a cord is wound in the circumferential direction as described in JP 2012-523340 A and JP 2014-210487 A, water penetrates from the tip of the cord into the tire or the cord rusts. It is preferable to suppress sticking.

This disclosure protects the tip of the cord in a resin-coated cord wound spirally.

The pneumatic tire according to the first aspect includes a carcass formed across a pair of bead cores and a resin-coated cord formed by covering the cord with a resin and disposed on the outer side in the tire radial direction of the carcass in the tire circumferential direction. A resin belt layer formed by being wound in a spiral shape; and a resin protective member fused to the distal end surface of the resin-coated cord and extending along the tire circumferential direction.

According to the pneumatic tire of the first aspect, a resin belt layer is formed by spirally winding a resin-coated cord formed by coating a cord with a resin in the tire circumferential direction. A resin protective member is fused to the front end surface of the resin-coated cord. For this reason, the tip of the cord is protected. The “tip surface” of the resin-coated cord is a surface where the tip of the cord is exposed.

In the pneumatic tire according to the second aspect, the protective member has a shape in which the tire radial direction dimension gradually decreases toward the tip in the tire circumferential direction.

In the pneumatic tire of the second aspect, the tire radial dimension at the tip of the protection member gradually decreases toward the tire circumferential tip, so that the rigidity of the protection member gradually decreases toward the tire circumferential tip. For this reason, the rigidity level difference of the tire peripheral direction in the front-end | tip part of a resin coating | coated cord can be relieve | moderated.

In the pneumatic tire according to the third aspect, the resin-coated cord has a shape in which the tire radial dimension at the tip gradually decreases toward the tip in the tire circumferential direction.

In the pneumatic tire of the third aspect, since the tire radial dimension at the tip of the resin-coated cord gradually decreases toward the tire circumferential tip, the rigidity of the resin-coated cord gradually decreases toward the tire circumferential tip. For this reason, the rigidity level difference of the tire peripheral direction in the front-end | tip part of a resin coating | coated cord can be relieve | moderated.

In the pneumatic tire according to the fourth aspect, chamfering is formed at the end of the resin belt layer in the tire width direction of the resin belt layer and the end of the protective member in the tire width direction.

In the pneumatic tire of the fourth aspect, since the chamfering is formed at the end of the resin-coated cord and the protective member in the tire width direction, the rigidity step in the tire width direction can be reduced.

A pneumatic tire according to a fifth aspect includes a bead core formed by spirally winding a resin-coated cord formed by coating a cord with a resin in a tire circumferential direction, and a carcass formed across a pair of the bead cores And a belt layer disposed on the outer side in the tire radial direction of the carcass, and a resin protective member fused to the front end surface of the resin-coated cord and extending along the tire circumferential direction. .

According to the pneumatic tire of the fifth aspect, a bead core is formed by spirally winding a resin-coated cord formed by coating a cord with a resin in the tire circumferential direction. A resin protective member is fused to the front end surface of the resin-coated cord. For this reason, the tip of the cord is protected.

The pneumatic tire according to the present disclosure can protect the tip of the cord in the coated cord wound in a spiral.

1 is a half cross-sectional view illustrating a pneumatic tire according to a first embodiment of the present disclosure. It is the perspective view which showed an example of the resin belt layer in the pneumatic tire which concerns on 1st Embodiment of this indication. It is sectional drawing of the resin belt layer in the pneumatic tire which concerns on 1st Embodiment of this indication. It is sectional drawing which shows the modification which coat | covered two reinforcement cords with coating resin in the pneumatic tire which concerns on 1st Embodiment of this indication. It is the top view which looked at the protection member in the pneumatic tire concerning a 1st embodiment of this indication from the direction along the tire diameter direction. It is the side view which looked at the protection member in the pneumatic tire concerning a 1st embodiment of this indication from the direction which followed a tire axial direction. It is a graph which shows the rigidity level difference of the tire peripheral direction in the tire peripheral direction front end surface vicinity of the resin coating cord in the pneumatic tire which concerns on 1st Embodiment of this indication. It is a top view showing the modification which made the protection member in the pneumatic tire concerning a 1st embodiment of this indication into the shape where a tire radial direction size decreases gradually. It is the side view which looked at the protection member made into the shape where a tire radial direction dimension reduces gradually from the direction along a tire axial direction. It is a graph which shows the rigidity level difference of the tire peripheral direction in the tire peripheral direction vicinity surface of the resin coating cord at the time of making a protection member into the shape where a tire radial direction dimension reduces gradually. It is a top view showing the modification which made the protection member in the pneumatic tire concerning a 1st embodiment of this indication into the shape where a tire width direction size decreases gradually. It is the side view which looked at the protection member made into the shape where a tire width direction dimension reduces gradually from the direction along the tire axial direction. It is a top view showing the modification which made the protection member in the pneumatic tire concerning a 1st embodiment of this indication into the shape where a tire radial direction size and a width direction size reduce gradually. It is the side view which looked at the protection member made into the shape where the tire radial direction dimension and the width direction dimension reduce gradually from the direction along the tire axial direction. It is the top view which looked at the protection member in the pneumatic tire concerning a 2nd embodiment of this indication from the direction which followed the tire radial direction. It is the side view which looked at the protection member in the pneumatic tire concerning a 2nd embodiment of this indication from the direction which followed a tire axial direction. It is a graph which shows the rigidity level difference of the tire peripheral direction in the tire peripheral direction front end surface of the resin coating cord in the pneumatic tire concerning a 2nd embodiment of this indication. It is a graph which shows the rigidity level | step difference at the time of reducing the rigidity of the protection member in the pneumatic tire which concerns on 2nd Embodiment of this indication. It is a top view showing the modification which made the protection member in the pneumatic tire concerning a 2nd embodiment of this indication into the shape where a tire radial direction size decreases gradually. It is the side view which looked at the protection member made into the shape where a tire radial direction dimension reduces gradually from the direction along a tire axial direction. It is a graph which shows the rigidity level difference of the tire peripheral direction in the tire peripheral direction vicinity surface of the resin coating cord at the time of making a protection member into the shape where a tire radial direction dimension reduces gradually. It is a graph which shows the rigidity level | step difference at the time of reducing the rigidity of the protection member made into the shape where a tire radial direction dimension reduces gradually. It is a top view showing the modification which made the protection member in the pneumatic tire concerning a 2nd embodiment of this indication into the shape where a tire width direction size decreases gradually. It is the side view which looked at the protection member made into the shape where a tire width direction dimension reduces gradually from the direction along the tire axial direction. It is a top view showing the modification which made the protection member in the pneumatic tire concerning a 2nd embodiment of this indication into the shape where a tire radial direction size and a width direction size reduce gradually. It is the side view which looked at the protection member made into the shape where the tire radial direction dimension and the width direction dimension reduce gradually from the direction along the tire axial direction. It is the top view which looked at the protection member in the pneumatic tire concerning a 3rd embodiment of this indication from the direction which followed the tire diameter direction. It is the side view which looked at the protection member in the pneumatic tire concerning a 3rd embodiment of an indication from the direction along the tire axial direction. It is a top view which shows the modification which made the protection member in the pneumatic tire which concerns on 3rd Embodiment of this indication the shape where a tire radial direction dimension reduces gradually. It is the side view which looked at the protection member in the pneumatic tire concerning a 3rd embodiment of this indication from the direction which followed the tire axial direction. It is a top view which shows the modification which made the protection member in the pneumatic tire which concerns on 3rd Embodiment of this indication the shape which a tire width direction dimension reduces gradually. It is the side view which looked at the protection member made into the shape where a tire width direction dimension reduces gradually from the direction along the tire axial direction. It is a top view which shows the modification which made the protection member in the pneumatic tire which concerns on 3rd Embodiment of this indication the shape where a tire radial direction dimension and a width direction dimension reduce gradually. It is the side view which looked at the protection member made into the shape where the tire radial direction dimension and the width direction dimension reduce gradually from the direction along the tire axial direction. It is a top view showing the modification which made the resin covering cord in the pneumatic tire concerning each embodiment of this indication into the shape where a tire radial direction size and a width direction size decrease gradually. It is the side view which looked at the resin-coated cord made into the shape where the tire radial direction dimension and the width direction dimension reduce gradually from the direction along the tire axial direction. In the modification which formed the resin coating cord in the pneumatic tire concerning each embodiment of this indication using two reinforcement cords, the plane which shows the modification which made the length of the tire peripheral direction of each reinforcement cord differ in length FIG. It is the side view which looked at the modification which made the tire circumferential direction length of each reinforcement cord differ in the resin covering cord formed using two reinforcement cords from the direction along the tire axial direction. It is a top view showing the modification which formed chamfering in the resin covering cord and protection member in the pneumatic tire concerning a 1st embodiment of this indication. It is the side view which looked at the resin coating cord and protective member which formed chamfering from the direction along the tire axial direction. It is CC sectional view taken on the line in FIG. 18A. It is the DD sectional view taken on the line in FIG. 18A. It is a top view showing the modification which formed chamfering in the protection member made into the shape where the resin covering cord and the tire radial direction size in the pneumatic tire concerning a 1st embodiment of this indication decrease gradually. It is the side view which looked at the protection member made into the shape where the resin-coated code | cord | chord which formed chamfering, and the tire radial direction dimension decreased gradually from the direction along a tire axial direction. It is CC sectional view taken on the line in FIG. 19A. FIG. 19B is a sectional view taken along line DD in FIG. 19A. FIG. 5 is a side view showing a modified example in which a bead core is formed of a resin-coated cord in a pneumatic tire according to an embodiment of the present disclosure, and a protective member is fused to a front end surface. It is sectional drawing of the bead core which formed with the resin coating cord and fuse | melted the protection member to the front end surface.

<First Embodiment>
FIG. 1 shows a cut surface (that is, along the tire circumferential direction) cut along the tire width direction and the tire radial direction of the pneumatic tire (hereinafter referred to as “tire 10”) according to the first embodiment of the present disclosure. One side of the cross section viewed from the direction indicated is shown. In the figure, an arrow W indicates the width direction of the tire 10 (tire width direction), and an arrow R indicates the radial direction of the tire 10 (tire radial direction). The tire width direction here refers to a direction parallel to the rotation axis of the tire 10. The tire radial direction refers to a direction orthogonal to the rotation axis of the tire 10. Reference sign CL indicates the equator plane of the tire 10 (tire equator plane). FIG. 1 shows the shape of the pneumatic tire 10 in a natural state before air filling.

In the present embodiment, the side closer to the rotation axis of the tire 10 along the tire radial direction is “inner side in the tire radial direction”, and the side farther from the rotation axis of the tire 10 along the tire radial direction is “outer side in the tire radial direction”. It describes. On the other hand, the side close to the tire equator plane CL along the tire width direction is described as “inner side in the tire width direction”, and the side far from the tire equator plane CL along the tire width direction is described as “outer side in the tire width direction”.

(tire)
As shown in FIG. 1, the tire 10 includes a pair of bead portions 12, a carcass 16 straddling a bead core 12 </ b> A embedded in each bead portion 12, and an end portion locked to the bead core 12 </ b> A, and a bead portion 12. A bead filler 12B that is buried and extends along the outer surface of the carcass 16 from the bead core 12A to the outer side in the tire radial direction, a resin belt layer 40 provided on the outer side in the tire radial direction of the carcass ply 14; And a tread 60 provided on the head. In FIG. 1, only the bead portion 12 on one side is shown. Further, the tire 10 is provided with a resin protective member 70 (see FIG. 4) fused to the distal end surface of a resin-coated cord 42 described later in the resin belt layer 40.

(Bead part)
In the pair of bead portions 12, bead cores 12A as wire bundles are respectively embedded. A carcass ply 14 straddles these bead cores 12A. The bead core 12A can employ various structures such as a circular cross section and a polygonal cross section. Further, for example, a hexagon can be adopted as the polygon, but in the present embodiment, it is a quadrangle.

A bead filler 12B is embedded in a region surrounded by the carcass ply 14 locked to the bead core 12A in the bead portion 12. The bead filler 12B extends from the bead core 12A to the outer side in the tire radial direction, and the thickness gradually decreases toward the outer side in the tire radial direction. In the 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 12BE of the bead filler 12B.

(Carcass)
The carcass 16 is formed by a single carcass ply 14 formed by coating a plurality of cords with a covering rubber. The carcass ply 14 extends in a toroidal shape from one bead core 12A to the other bead core 12A to constitute a tire skeleton. Further, the end portion side of the carcass ply 14 is locked to the bead core 12A. Specifically, the carcass ply 14 includes a main body portion 14A that extends from one bead core 12A to the other bead core 12A, and a folded portion 14B that is folded outward from the bead core 12A in the tire radial direction.

In the present embodiment, the carcass ply 14 is a radial carcass. The material of the carcass ply 14 is not particularly limited, and rayon, nylon, polyethylene naphthalate (PEN), polyethylene terephthalate (PET), aramid, glass fiber, carbon fiber, steel, or the like can be used. From the viewpoint of weight reduction, an organic fiber cord is preferable. In addition, the number of carcass shots is in the range of 20 to 60 pieces / 50 mm, but is not limited to this range. In the present embodiment, the carcass 16 is formed by the single carcass ply 14, but the carcass 16 may be formed by a plurality of carcass plies.

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

(Resin belt layer)
A resin belt layer 40 is disposed outside the crown portion of the carcass 16, in other words, outside the carcass 16 in the tire radial direction. As shown in FIG. 2, the resin belt layer 40 has a ring-shaped ridge formed by winding one resin-coated cord 42 spirally around the outer circumferential surface of the carcass 16 in the tire circumferential direction. The front end surfaces 42E1 and 42E2 in the circumferential direction of the resin-coated cord 42 are surfaces along the tire width direction and the radial direction, and are arranged at different positions in the tire circumferential direction. Note that “spiral” indicates a state in which one resin-coated cord 42 is wound at least one turn around the carcass 16.

The resin-coated cord 42 is configured by coating one reinforcing cord 42C with a coating resin 42S, and has a substantially square cross section as shown in FIG. 3A. The coating resin 42S is closely bonded to the outer peripheral surface of the carcass 16 by an adhesive or vulcanization adhesion.

Also, the coating resins 42S adjacent to each other in the tire width direction are joined by fusion bonding. Thereby, the resin belt layer 40 in which the reinforcing cord 42C is covered with the covering resin 42S is formed.

Further, the reinforcing cord 42C in the resin belt layer 40 of the present embodiment is a steel cord whose outer peripheral surface is plated with cobalt. The steel cord is mainly composed of steel and can contain various trace contents such as carbon, manganese, silicon, phosphorus, sulfur, copper, and chromium. The plating material is not limited to cobalt, and nickel or the like can be used. The end surface of the reinforcing cord 42C is not plated, and the solid steel is exposed.

The width BW of the resin belt layer 40 measured along the tire axial direction is preferably 75% or more with respect to the contact width TW of the tread 60 measured along the tire axial direction. Thereby, the rigidity in the vicinity of the shoulder 39 can be increased. The upper limit of the width BW of the resin belt layer 40 is preferably 110% with respect to the ground contact width TW. Thereby, the weight increase of the tire 10 can be suppressed.

Here, the contact width TW of the tread 60 means that the tire 10 is mounted on a standard rim stipulated in JATMA YEAR BOOK (2018 version, Japan Automobile Tire Association Standard), and applicable size / prior rating in JATMA YEAR BOOK. Is filled with 100% of the internal pressure corresponding to the maximum load capacity (that is, the bold load in the internal pressure-load capacity correspondence table) (ie, the maximum air pressure), and the axis of rotation 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.

Note that the embodiment of the present disclosure is not limited thereto, and the reinforcing cord 42C in the resin belt layer 40 may be a monofilament cord or a cord in which a plurality of filaments are twisted instead of the steel cord. Further, organic fibers such as aramid, carbon, and the like may be used. Various designs can be adopted for the twist structure, and various cross-sectional structures, twist pitches, twist directions, and distances between adjacent filaments can be used. Furthermore, it is possible to adopt a cord in which filaments of different materials are twisted together, and the cross-sectional structure is not particularly limited, and various twisted structures such as single twist, layer twist, and double twist can be adopted.

The resin belt layer 40 and the tread 60 are integrated by an adhesive or vulcanization adhesion.

The resin material used for the resin belt layer 40 is a thermoplastic resin. However, the embodiment of the present disclosure is not limited thereto, and examples of the resin material include thermoplastic elastomers, thermosetting resins, (meth) acrylic resins, EVA resins, vinyl chloride resins, fluorine resins, and silicone resins. In addition to general-purpose resins, engineering plastics (including super engineering plastics) can be used. The resin material here does not include vulcanized rubber.

Thermoplastic resin (including thermoplastic elastomer) refers to a polymer compound that softens and flows as the temperature rises and becomes relatively hard and strong when cooled. In the present specification, among these, the material softens and flows with increasing temperature, and becomes relatively hard and strong when cooled, and a high molecular compound having rubber-like elasticity is a thermoplastic elastomer, and the material increases with increasing temperature. Is softened, fluidized, and becomes a relatively hard and strong state when cooled, and a high molecular compound having no rubber-like elasticity is distinguished as a thermoplastic resin that is not an elastomer.

Thermoplastic resins (including thermoplastic elastomers) include polyolefin-based thermoplastic elastomers (TPO), polystyrene-based thermoplastic elastomers (TPS), polyamide-based thermoplastic elastomers (TPA), polyurethane-based thermoplastic elastomers (TPU), and polyesters. Thermoplastic thermoplastic elastomer (TPC), dynamically crosslinked thermoplastic elastomer (TPV), polyolefin thermoplastic resin, polystyrene thermoplastic resin, polyamide thermoplastic resin, polyester thermoplastic resin, etc. Can be mentioned.

The thermosetting resin refers to a polymer compound that forms a three-dimensional network structure as the temperature rises and cures, and examples thereof include a phenol resin, an epoxy resin, a melamine resin, and a urea resin.

(Protective member)
As shown in FIG. 2, in the resin belt layer 40, the front ends of the reinforcing cords 42C are exposed on the front end surfaces 42E1 and 42E2 in the circumferential direction of the resin-coated cord 42. As shown in FIG. 4A and FIG. 4B, a resin protective member 70 is fused to the front end surfaces 42E1 and 42E2. The protection member 70 is a cover member that protects the tip of the reinforcing cord 42C. Further, the protection member 70 is a rigidity step reducing member that reduces the rigidity step at the tip of the resin-coated cord 42. In addition, illustration of the protection member 70 is abbreviate | omitted in FIG.

The protective member 70 is formed using the same resin as the coating resin 42S, and extends along the tire circumferential direction (arrow S direction). Further, the cross-sectional shape of the protective member 70 along the tire width direction and the radial direction is substantially equal to the cross-sectional shape of the resin-coated cord 42.

Note that the protective member according to the embodiment of the present disclosure can have various shapes. As an example, the protective member may have a shape in which the tire radial dimension gradually decreases toward the tip in the tire circumferential direction, like a protective member 72 shown in FIGS. 5A and 5B. The inclined surface 72S is inclined toward the carcass 16. The “shape in which the tire radial direction dimension gradually decreases” may be a curved shape, a stepped shape, or the like in addition to the linear shape shown in FIG. 5B.

Further, although the protective member 72 has a shape in which the tire radial dimension gradually decreases in the entire tire circumferential direction, it is only necessary to gradually decrease the tire radial dimension only at the circumferential tip.

As another example, the protective member may have a shape in which the size in the tire width direction gradually decreases toward the tip in the tire circumferential direction, as in the protective member 74 shown in FIGS. 6A and 6B. The inclined surface 74S is inclined toward the resin-coated cord 42 adjacent in the tire width direction. The “shape in which the tire width direction dimension gradually decreases” may be a curved shape, a stepped shape, or the like in addition to the linear shape shown in FIG. 6A.

Further, although the protective member 74 has a shape in which the tire width direction dimension gradually decreases in the entire tire circumferential direction, it is only necessary to gradually decrease the tire width direction dimension at least at the front end portion in the circumferential direction.

As another example, the protective member may have a shape in which the tire radial direction dimension and the tire width direction dimension gradually decrease toward the tip in the tire circumferential direction, as in the protective member 76 shown in FIGS. 7A and 7B. The two inclined surfaces 76S are inclined toward the carcass 16 or the resin-coated cord 42 adjacent in the tire width direction, respectively. The “shape in which the tire radial dimension gradually decreases” may be a curved shape or the like in addition to the linear shape shown in FIG. 5B.

(tread)
As shown in FIG. 1, a tread 60 is provided outside the resin belt layer 40 in the tire radial direction. The tread 60 is a part that contacts the road surface during traveling. A plurality of circumferential grooves 62 extending in the tire circumferential direction are formed on the tread surface of the tread 60. The shape and number of the circumferential grooves 62 are appropriately set according to the performance such as drainage performance and steering stability required for the tire 10.

(Function)
In the tire 10 according to the embodiment of the present disclosure, the resin belt layer 40 is formed by winding the resin-coated cord 42 spirally in the tire circumferential direction. The resin-coated cord 42 is formed by coating the reinforcing cord 42C with a coating resin 42S. A resin protective member 70 is fused to the front end surface of the resin-coated cord 42. For this reason, the tip of the reinforcing cord 42C is protected. For example, since the tip of the reinforcing cord 42C is covered with resin, it is difficult to rust. Further, it is possible to prevent moisture from penetrating from the front end surface of the resin-coated cord 42 through the reinforcing cord 42 </ b> C to the inside of the resin-coated cord 42.

The protective member 70 is formed using the same resin as the coating resin 42S, but the reinforcing cord 42C is not embedded in the protective member 70. For this reason, the protection member 70 has lower rigidity than the resin-coated cord 42. As a result, as shown in FIG. 4C, the rigidity in the tire circumferential direction in the vicinity of the front end surfaces 42E1 and 42E2 (that is, the front end portion) of the resin-coated cord 42 can be prevented from suddenly changing from the front end surfaces 42E1 and 42E2. That is, the rigidity step can be reduced.

Note that the horizontal axis (S) in FIG. 4C indicates the circumferential position. The vertical axis (G) indicates the rigidity at the cross-sectional position where the reinforcing cord 42C passes in the outermost resin-coated cord 42 in the tire width direction. The same applies to FIGS. 5C, 8C, 8D, 9C, and 9D described later.

When the protective member 72 shown in FIGS. 5A and 5B is used instead of the protective member 70, the tire radial direction dimension of the protective member 72 gradually decreases toward the tip in the tire circumferential direction. For this reason, as shown to FIG. 5C, the rigidity of a tire circumferential direction also reduces gradually. Thereby, the rigidity step can be relaxed. Further, even if a protective member 74 (see FIGS. 6A and 6B) and a protective member 76 (see FIGS. 7A and 7B) are used instead of the protective member 70, the rigidity step can be reduced.

Second Embodiment
In the first embodiment, the front end surfaces 42E1 and 42E2 of the resin-coated cord 42 are surfaces along the tire width direction and the radial direction, and are substantially perpendicular to the tire circumferential direction. On the other hand, as shown in FIGS. 8A and 8B, the resin-coated cord 42A according to the second embodiment has the tip surfaces 42AE1 and 42AE2 inclined in a range of less than 90 ° with respect to the tire circumferential direction and the radial direction. Further, the front end surfaces 42AE1 and 42AE2 are inclined toward the carcass 16. That is, the resin-coated cord 42A has a shape in which the tire radial direction dimension of the tip portion gradually decreases toward the tip in the tire circumferential direction. The “shape in which the tire radial direction dimension gradually decreases” can be a straight shape, a curved shape, or the like.

A protective member is fused to the front end surfaces 42AE1 and 42AE2 of the resin-coated cord 42A having a shape in which the tire radial dimension gradually decreases toward the front end in the tire circumferential direction. As an example, this protective member can be a protective member 70A. Similarly to the protective member 70, the protective member 70 </ b> A has a cross-sectional shape along the tire width direction and the radial direction at the front end portion substantially equal to the cross-sectional shape of the resin-coated cord 42.

Even if the resin-coated cord 42A and the protective member 70A are used, the rigidity step in the tire circumferential direction can be reduced as shown in FIG. 8C. The protective member 70A may be formed of a resin having a lower rigidity than the coating resin 42S. In this case, as shown in FIG. 8D, the rigidity step can be relaxed.

As another example, the protective member fused to the front end surfaces 42AE1 and 42AE2 of the resin-coated cord 42A can be a protective member 72A as shown in FIGS. 9A and 9B. Similarly to the protective member 72, the protective member 72A has a shape in which the tire radial dimension of the tip portion gradually decreases toward the tip in the tire circumferential direction.

Even if the resin-coated cord 42A and the protective member 72A are used, the rigidity step in the tire circumferential direction can be reduced as shown in FIG. 9C. The protective member 72A may be formed of a resin having a lower rigidity than the coating resin 42S. In this case, as shown in FIG. 9D, the rigidity step can be relaxed. As described for the protective members 70A and 70B, the embodiment in which the protective member is formed of a resin having lower rigidity than the coating resin 42S can be applied to the other embodiments.

As another example, the protective member fused to the tip surfaces 42AE1 and 42AE2 of the resin-coated cord 42A can be a protective member 74A as shown in FIGS. 10A and 10B. Similarly to the protection member 74, the protection member 74 </ b> A has a shape in which the tire width direction dimension of the tip portion gradually decreases toward the tip in the tire circumferential direction.

As yet another example, the protective member fused to the front end surfaces 42AE1 and 42AE2 of the resin-coated cord 42A can be a protective member 76A as shown in FIGS. 11A and 11B. Similarly to the protection member 76, the protection member 76A has a shape in which the tire radial direction dimension and the tire width direction dimension of the front end portion gradually decrease toward the front end in the tire circumferential direction.

<Third Embodiment>
In the first embodiment, the front end surfaces 42E1 and 42E2 of the resin-coated cord 42 are surfaces along the tire width direction and the radial direction, and are substantially perpendicular to the tire circumferential direction. On the other hand, as shown in FIGS. 12A and 12B, the resin-coated cord 42B in the third embodiment is inclined such that the front end surfaces 42BE1 and 42BE2 are less than 90 ° with respect to the tire circumferential direction. Further, the tip surfaces 42BE1 and 42BE2 are inclined toward the resin-coated cord 42 adjacent in the tire width direction. That is, the resin-coated cord may have a shape in which the size in the tire width direction of the tip portion gradually decreases toward the tip in the tire circumferential direction.

A protective member is fused to the front end surfaces 42BE1 and 42BE2 of the resin-coated cord 42B having a shape in which the tire width direction dimension gradually decreases toward the front end in the tire circumferential direction. As an example, this protective member can be a protective member 70B. Similarly to the protective member 70, the protective member 70 </ b> B has a cross-sectional shape along the tire width direction and a radial direction substantially equal to the cross-sectional shape of the resin-coated cord 42.

As another example, the protective member fused to the front end surfaces 42BE1 and 42BE2 of the resin-coated cord 42B can be a protective member 72B as shown in FIGS. 13A and 13B. Similarly to the protection member 72, the protection member 72 </ b> B has a shape in which the tire radial direction dimension gradually decreases toward the tire circumferential direction front end.

As another example, the protective member fused to the tip surfaces 42BE1 and 42BE2 of the resin-coated cord 42B can be a protective member 74B as shown in FIGS. 14A and 14B. Similarly to the protection member 74, the protection member 74 </ b> B has a shape in which the tire width direction dimension of the tip portion gradually decreases toward the tip in the tire circumferential direction.

As another example, the protective member fused to the front end surfaces 42BE1 and 42BE2 of the resin-coated cord 42B can be a protective member 76B as shown in FIGS. 15A and 15B. Similarly to the protection member 76, the protection member 76B has a shape in which the tire radial direction dimension and the tire width direction dimension of the front end portion gradually decrease toward the front end in the tire circumferential direction.

<Other embodiments>
The resin-coated cord 42A according to the second embodiment has a shape in which the tire radial direction dimension of the tip portion gradually decreases toward the tip in the tire circumferential direction. Further, the resin-coated cord 42B in the third embodiment has a shape in which the tire width direction dimension of the tip portion gradually decreases toward the tip in the tire circumferential direction, but the embodiment of the present disclosure is not limited thereto.

For example, as in the front end faces 42DE1 and 42DE2 of the resin-coated cord 42D shown in FIGS. 16A and 16B, the front end portion of the resin-coated cord has both the tire radial direction dimension and the tire width direction dimension toward the front end in the tire circumferential direction. The shape may be gradually reduced. Each of the embodiments described above can be applied as a protective member that is fused to the front end surfaces 42DE1 and 42DE2.

Further, in each of the above embodiments, as shown in FIG. 3A, the resin belt layer 40 is formed by coating one reinforcing cord 42C with a coating resin 42S to form a substantially square resin-coated cord 42. Although it formed using the covering cord 42, embodiment of this indication is not restricted to this.

For example, as shown in FIG. 3B, a plurality of (for example, two) reinforcing cords 44C may be formed using a resin-coated cord 44 having a substantially parallelogram cross section formed by coating with a coating resin 44S. .

In this case, as the shape of the tip surface of the resin-coated cord 44, each shape shown in the above embodiments can be applied. Further, as shown in FIGS. 17A and 17B, among the reinforcing cords 44C, the reinforcing cords 44C arranged on the outer side in the tire width direction may be formed shorter than the reinforcing cords 44C arranged on the inner side in the tire width direction. Each reinforcing cord 44C is formed with stepped end surfaces 44E1 and 44E2 so that the end surfaces are exposed.

Further, as the protective member to be fused to the front end surfaces 44E1 and 44E2, the above-described embodiments can be applied, and a protective member 78 may be formed in a step shape.

Furthermore, a chamfer R may be formed at the ends of the resin-coated cord and the protective member in the tire width direction, like the resin-coated cord 42 and the protective member 70 in FIGS. 18A, 18B, 18C, and 18D. By forming the chamfer R, the rigidity step in the tire width direction can be reduced. As shown in FIGS. 19A, 19B, 19C, and 19D, the chamfer R includes a protective member 72 having a shape in which the tire radial direction dimension and the tire width direction dimension gradually decrease toward the front end in the tire circumferential direction. 74 (see FIGS. 6A and 6B).

In each of the above-described embodiments, it has been described that the bead core 12A shown in FIG. 1 is a wire bundle. However, the bead core 12A may be formed of a resin-coated cord. That is, the bead core 12A may be formed of the resin-coated cord 46 as shown in FIGS. 20A and 20B.

The resin-coated cord 46 can be configured by coating one or a plurality of reinforcing cords 46C with a coating resin 46S. However, in this embodiment, as an example, as shown in FIG. 20B, three reinforcing cords 46C are covered with a coating resin 46S. As shown in FIG. 20A, the resin-coated cord 46 is disposed by winding about 3 turns in the tire circumferential direction. The coating resins 46S adjacent to each other in the tire radial direction are joined by fusion bonding. Thereby, the bead core 12A in which the reinforcing cord 46C is coated with the coating resin 46S is formed. Note that the number of windings of the resin-coated cord 46 (three in the present embodiment) and the number of reinforcing cords 46C disposed per winding (three in the present embodiment) can be appropriately increased or decreased depending on the purpose. .

It is preferable to fuse a protective member to the front end surfaces 46E1 and 46E2 of the resin-coated cord 46. Specifically, the front end surfaces 46E1 and 46E2 of the resin-coated cord 46 are similar to the protective members 70, 70A, 70B, 72, 72A, 72B, 74, 74A, 74B, 76, 76A, 76B, 78 described above. The shaped protective member can be fused. 20 shows an example in which the protective member 72 is fused.

Moreover, although the front end surfaces 46E1 and 46E2 are formed along the tire radial direction in FIG. 20, the embodiment of the present disclosure is not limited to this, and the shapes of the front end surfaces 46E1 and 46E2 can be changed as appropriate. it can.

When the bead core 12A is formed of the resin-coated cord 46 and the protective member is fused to the tip surfaces 46E1 and 46E2 of the resin-coated cord 46, the tip surfaces 42E1 and 42E2 of the resin-coated cord 42 in the resin belt layer 40 are However, it is not always necessary to provide a protective member such as the protective member 70. Further, the resin belt layer 40 is not necessarily provided as a belt layer provided on the outer side in the tire radial direction of the carcass 16, and the resin belt layer 40 may be replaced with a rubber belt layer in which a cord is covered with rubber.

That is, in the present disclosure, it is sufficient that at least one of the belt layer and the bead core 12A includes a resin-coated cord and a protective member. Thus, the present disclosure can be implemented in various ways.

The disclosure of Japanese Patent Application No. 2018-114849 filed on June 15, 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 stated to be incorporated by reference, Incorporated herein by reference.

Claims (5)

A carcass formed across a pair of bead cores;
A resin belt layer formed on the outer side in the tire radial direction of the carcass and formed by spirally winding a resin-coated cord formed by coating the cord with a resin in the tire circumferential direction;
A protective member made of resin fused to the front end surface of the resin-coated cord and extending along the tire circumferential direction;
Pneumatic tire with The protective member has a shape in which the tire radial direction dimension of the tip portion gradually decreases toward the tip in the tire circumferential direction,
The pneumatic tire according to claim 1. The resin-coated cord has a shape in which the tire radial direction dimension gradually decreases toward the tip in the tire circumferential direction,
The pneumatic tire according to claim 1 or claim 2. The pneumatic tire according to any one of claims 1 to 3, wherein a chamfer is formed at an end of the resin belt layer in the tire width direction of the resin belt layer and an end of the protective member in the tire width direction. A bead core formed by spirally winding a resin-coated cord formed by coating a cord with a resin in the tire circumferential direction;
A carcass formed across a pair of the bead cores;
A belt layer disposed on the outer side in the tire radial direction of the carcass;
A protective member made of resin fused to the front end surface of the resin-coated cord and extending along the tire circumferential direction;
Pneumatic tire with

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