JP2019217822A - Pneumatic tire - Google Patents

Abstract

To protect a tip of a cord in a spirally wound resin-coated cord.SOLUTION: A pneumatic tire includes: a carcass formed so as to astride a pair of bead cores; a resin belt layer 40 which is arranged outside in a tire radial direction of the carcass, and is formed by spirally winding a resin-coated cord 42 formed by coating a cord (reinforcement cord 42C) with a resin (coated resin 42S) in a tire circumferential direction; and a resin protective member 70 which is fused to a tip surface 42E1 of the resin-coated cord and extends in the tire circumferential direction.SELECTED DRAWING: Figure 4

Description

  The present invention relates to a pneumatic tire.

  Patent Literature 1 below 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 has been demanded to use a resin material (for example, a thermoplastic resin, a thermoplastic elastomer, or the like) as a tire material because of its lightness, ease of molding, and ease of recycling. Patent Literature 2 below discloses a tire in which a reinforcing cord member is spirally wound around a crown portion of a resin tire frame member.

JP 2012-523340 A JP 2014-210487 A

  As described in Patent Literatures 1 and 2, in a tire in which a cord is wound along a circumferential direction, it is preferable to prevent water from penetrating into the tire from the tip of the cord and to prevent the cord from rusting.

  The present invention has been made in consideration of the above-described circumstances, and has as its object to protect a tip end of a spirally wound resin-coated cord.

  The pneumatic tire according to claim 1, a carcass formed straddling a pair of bead cores, and a resin-coated cord formed by covering the cord with a resin, which is disposed outside the carcass in the tire radial direction, in the tire circumferential direction. A resin belt layer formed by spirally winding; and a resin protection member fused to the tip end surface of the resin-coated cord and extending along the tire circumferential direction.

  According to the pneumatic tire of the first aspect, the resin-coated cord formed by coating the cord with the resin is spirally wound in the tire circumferential direction to form the resin belt layer. A protective member made of resin is fused to the distal 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 a second aspect, the protective member has a shape in which a tire radial dimension at a tip portion gradually decreases toward a tip in a tire circumferential direction.

  In the pneumatic tire according to the second aspect, the tire radial dimension at the distal end of the protective member gradually decreases toward the distal end in the tire circumferential direction, so that the rigidity of the protective member gradually decreases toward the distal end in the tire circumferential direction. For this reason, the rigidity step in the tire circumferential direction at the tip portion of the resin-coated cord can be reduced.

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

  In the pneumatic tire according to the third aspect, the tire radial dimension of the distal end portion of the resin-coated cord gradually decreases toward the distal end in the tire circumferential direction, so that the rigidity of the resin-coated cord gradually decreases toward the distal end in the tire circumferential direction. For this reason, the rigidity step in the tire circumferential direction at the tip portion of the resin-coated cord can be reduced.

  In the pneumatic tire of the fourth aspect, a chamfer is formed at an end in the tire width direction of the resin-coated cord and the protection member at an end in the tire width direction of the resin belt layer.

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

  The pneumatic tire according to claim 5, wherein a bead core formed by spirally winding a resin-coated cord formed by coating the cord with a resin in a tire circumferential direction, and a carcass formed over a pair of the bead cores. A belt layer disposed radially outside the carcass in the tire radial direction; and a resin protection member fused to the tip end surface of the resin-coated cord and extending along the tire circumferential direction. .

  According to the pneumatic tire of the fifth aspect, the bead core is 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 is fused to the distal end surface of the resin-coated cord. For this reason, the tip of the cord is protected.

  ADVANTAGE OF THE INVENTION According to the pneumatic tire which concerns on this invention, the front-end | tip of a cord can be protected in the spirally wound covering cord.

1 is a half sectional view showing a pneumatic tire according to a first embodiment of the present invention. It is a perspective view showing an example of a resin belt layer in a pneumatic tire concerning a 1st embodiment of the present invention. (A) is a cross-sectional view of a resin belt layer in the pneumatic tire according to the first embodiment of the present invention, and (B) is a cross-sectional view showing a modification in which two reinforcing cords are covered with a coating resin. (A) is a plan view of the protection member in the pneumatic tire according to the first embodiment of the present invention as viewed from a direction along the tire radial direction, and (B) is a side view as viewed from a direction along the tire axial direction. (C) is a graph showing a rigidity step in the tire circumferential direction in the vicinity of the front end face of the resin-coated cord in the tire circumferential direction. (A) is a top view which shows the modification which made the protection member in the pneumatic tire which concerns on 1st Embodiment of this invention the shape which tire diameter direction dimension reduces gradually, (B) was along the tire axial direction. It is a side view seen from the direction, and (C) is a graph which shows the rigidity step of the tire peripheral direction in the tire peripheral direction front end surface vicinity of a resin coating cord. (A) is a top view which shows the modification which made the protection member in the pneumatic tire which concerns on 1st Embodiment of this invention the shape which tire width direction dimension reduces gradually, (B) was along the tire axial direction. It is the side view seen from the direction. (A) is a top view showing a modification in which the protection member in the pneumatic tire according to the first embodiment of the present invention has a shape in which the tire radial dimension and the width dimension are gradually reduced, and (B) is a tire shaft. It is the side view seen from the direction along the direction. (A) is a plan view of a protection member in a pneumatic tire according to a second embodiment of the present invention as viewed from a direction along a tire radial direction, and (B) is a side view as viewed from a direction along a tire axial direction. (C) is a graph showing a rigidity step in the tire circumferential direction near the front end surface of the resin-coated cord in the tire circumferential direction, and (D) is a graph showing a rigidity step when the rigidity of the protective member is reduced. (A) is a top view which shows the modification which made the protection member in the pneumatic tire which concerns on 2nd Embodiment of this invention into the shape which tire radial dimension reduces gradually, (B) was along the tire axial direction. It is the side view seen from the direction, (C) is a graph which shows the rigidity step of the tire circumferential direction near the tire circumferential direction front end surface of a resin coating cord, (D) The rigidity step when the rigidity of a protection member is made small. FIG. (A) is a top view which shows the modification which made the protection member in the pneumatic tire which concerns on 2nd Embodiment of this invention the shape which tire width direction dimension reduces gradually, (B) was along the tire axial direction. It is the side view seen from the direction. (A) is a top view which shows the modification which made the protection member in the pneumatic tire which concerns on 2nd Embodiment of this invention the shape which a tire radial direction dimension and a width direction dimension decreased gradually, and (B) is a tire axis | shaft. It is the side view seen from the direction along the direction. (A) is a plan view of a protection member in a pneumatic tire according to a third embodiment of the present invention as viewed from a direction along a tire radial direction, and (B) is a side view as viewed from a direction along a tire axial direction. is there. (A) is a top view which shows the modification which made the protection member in the pneumatic tire which concerns on 3rd Embodiment of this invention the shape which tire radial dimension reduces gradually, (B) was along the tire axial direction. It is the side view seen from the direction. (A) is a top view showing a modification in which the protection member in the pneumatic tire according to the third embodiment of the present invention has a shape in which the dimension in the tire width direction gradually decreases, and (B) is a plan view along the tire axial direction. It is the side view seen from the direction. (A) is a top view which shows the modification which made the protection member in the pneumatic tire which concerns on 3rd Embodiment of this invention into the shape which a tire radial dimension and a width dimension reduced gradually, and (B) tire axis | shaft. It is the side view seen from the direction along the direction. (A) is a top view which shows the modification which made the resin coating cord in the pneumatic tire which concerns on each embodiment of this invention into the shape which a tire radial direction dimension and a width direction dimension decreased gradually, and (B) is a tire axis | shaft. It is the side view seen from the direction along the direction. (A) is a modification in which the resin-coated cord in the pneumatic tire according to each embodiment of the present invention is formed using two reinforcement cords, and the length of each reinforcement cord in the tire circumferential direction is different. It is a top view which shows an example, (B) is the side view seen from the direction along the tire axial direction. (A) is a plan view showing a modified example in which the resin-coated cord and the protection member in the pneumatic tire according to the first embodiment of the present invention are formed with a chamfer, and (B) is viewed from a direction along the tire axial direction. It is a side view. (A) is a plan view showing a modified example in which a chamfer is formed on a resin-coated cord and a protective member having a shape in which a tire radial dimension is gradually reduced in the pneumatic tire according to the first embodiment of the present invention, and (B). FIG. 2 is a side view as seen from a direction along the tire axial direction. (A) is a side view showing a modification in which a bead core is formed of a resin-coated cord in the pneumatic tire according to the embodiment of the present invention, and a protection member is fused to a front end surface, and (B) is a cross-sectional view of the bead core It is.

<First embodiment>
FIG. 1 shows a cut surface (along the tire circumferential direction) cut along a tire width direction and a tire radial direction of a pneumatic tire (hereinafter, referred to as “tire 10”) according to the first embodiment of the present invention. (A cross section viewed from the direction) is shown. The arrow W in the figure indicates the width direction of the tire 10 (tire width direction), and the arrow R indicates the radial direction of the tire 10 (tire radial direction). Here, the tire width direction 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 symbol CL indicates the equatorial plane of the tire 10 (tire equatorial 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 “inside in the tire radial direction”, and the side farther from the rotation axis of the tire 10 along the tire radial direction is “outside in the tire radial direction”. It is described. On the other hand, the side closer to the tire equatorial plane CL along the tire width direction is referred to as “inside in the tire width direction”, and the side farther from the tire equatorial plane CL along the tire width direction is referred to 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 having a bead core 12 </ b> A embedded in each bead portion 12, and a carcass 16 having an end locked to the bead core 12 </ b> A, and a bead portion 12. A bead filler 12B that is buried and extends from the bead core 12A outward in the tire radial direction along the outer surface of the carcass 16, a resin belt layer 40 provided outside the carcass ply 14 in the tire radial direction, and a tire radial outside of the resin belt layer 40. And a tread 60 provided on the vehicle. In FIG. 1, only one bead portion 12 is shown. In addition, the tire 10 includes a resin protection member 70 (see FIG. 4) fused to a distal end surface of a resin-coated cord 42 described later in the resin belt layer 40.

(Bead part)
A bead core 12A, which is a wire bundle, is embedded in each of the pair of bead portions 12. A carcass ply 14 straddles these bead cores 12A. The bead core 12A can adopt various structures such as a circular or polygonal cross section. For example, a hexagon can be adopted as the polygon, but in the present embodiment, it is a quadrangle.

  In a region surrounded by the carcass ply 14 locked to the bead core 12A in the bead portion 12, a bead filler 12B extending outward from the bead core 12A in the tire radial direction and gradually decreasing in thickness toward the tire radial direction is embedded. ing. In the tire 10, a portion of the bead filler 12 </ b> B inside the tire radial direction from the tire radial outer end 12 </ b> BE is a bead portion 20.

(Carcass)
The carcass 16 is formed by a single carcass ply 14 formed by covering a plurality of cords with a covering rubber. The carcass ply 14 extends in a toroidal form from one bead core 12A to the other bead core 12A to form a skeleton of a tire. The end of the carcass ply 14 is locked to the bead core 12A. Specifically, the carcass ply 14 includes a main body portion 14A extending from one bead core 12A to the other bead core 12A, and a folded portion 14B folded from the bead core 12A outward 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 may be rayon, nylon, polyethylene naphthalate (PEN), polyethylene terephthalate (PET), aramid, glass fiber, carbon fiber, steel, or the like. From the viewpoint of weight reduction, an organic fiber cord is preferable. In addition, the number of carcass to be driven is set in a range of 20 to 60/50 mm, but is not limited to this range. Further, in the present embodiment, the carcass 16 is formed by one 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 this embodiment, the tire case 25 is constituted by the bead core 12A, the carcass 16, the bead filler 12B, the inner liner 22, and the side rubber layer 24. The tire case 25 is, in other words, 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 hoop formed by spirally winding a single resin-coated cord 42 around the outer peripheral surface of the carcass 16 in the tire circumferential direction. ), And the distal 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. The “spiral” indicates a state in which one resin-coated cord 42 is wound around the carcass 16 at least once.

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

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

  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. Further, the plating material is not limited to cobalt, but nickel or the like can be used. The end face of the reinforcing cord 42C is not plated, and solid steel is exposed.

  It is preferable that the width BW of the resin belt layer 40 measured along the tire axial direction is 75% or more with respect to the contact width TW of the tread 60 measured along the tire axial direction. Thereby, the rigidity near the shoulder 39 can be increased. Note that the upper limit of the width BW of the resin belt layer 40 is preferably set to 110% with respect to the contact width TW. Thereby, an increase in the weight 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 edition, Japan Automobile Tire Association Standard), and the applicable size and ply rating in JATMA YEAR BOOK. 100% internal pressure of the air pressure (maximum air pressure) corresponding to the maximum load capacity (internal pressure-load capacity correspondence table) in the above, so that the rotation axis is parallel to the horizontal flat plate in the stationary state It is the one when placed and the mass corresponding to the maximum load capacity is added. When the TRA standard and the ETRTO standard are applied at the place of use or the place of manufacture, the respective standards are followed.

  The embodiment of the present invention is not limited to this. As the reinforcing cord 42C in the resin belt layer 40, a monofilament cord or a cord obtained by twisting a plurality of filaments can be used 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. Further, by adopting a cord in which filaments of different materials are twisted, the cross-sectional structure is not particularly limited, and various twist structures such as single twist, layer twist, and multiple twist can be adopted.

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

  The resin material used for the resin belt layer 40 is a thermoplastic resin. However, embodiments of the present invention are not limited to this. For example, as a resin material, a thermoplastic elastomer, a thermosetting resin, a (meth) acrylic resin, an EVA resin, a vinyl chloride resin, a fluorine resin, a silicone resin, or the like. In addition to general-purpose resins, engineering plastics (including super engineering plastics) and the like can be used. The resin material here does not include vulcanized rubber.

  A thermoplastic resin (including a thermoplastic elastomer) refers to a polymer compound in which a material softens and flows with an increase in temperature, and becomes relatively hard and strong when cooled. In the present specification, among these materials, the material softens and flows with an increase in temperature, becomes a relatively hard and strong state when cooled, and a polymer compound having rubber-like elasticity is made into a thermoplastic elastomer, and the material with the increase in temperature becomes a material. Softens, flows, and becomes relatively hard and strong when cooled, and distinguishes a polymer compound having no rubber-like elasticity as a non-elastomer thermoplastic resin.

  Examples of thermoplastic resins (including thermoplastic elastomers) include polyolefin-based thermoplastic elastomer (TPO), polystyrene-based thermoplastic elastomer (TPS), polyamide-based thermoplastic elastomer (TPA), polyurethane-based thermoplastic elastomer (TPU), and polyester. Thermoplastic elastomer (TPC), dynamically crosslinked thermoplastic elastomer (TPV), polyolefin thermoplastic resin, polystyrene thermoplastic resin, polyamide thermoplastic resin, polyester thermoplastic resin, etc. No.

  The thermosetting resin refers to a polymer compound that forms a three-dimensional network structure and cures with an increase in temperature, 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 distal ends of the reinforcing cords 42C are exposed at the distal end surfaces 42E1 and 42E2 of the resin-coated cords 42 in the circumferential direction. As shown in FIGS. 4A and 4B, a resin protection member 70 is fused to the distal end surfaces 42E1 and 42E2. The protection member 70 is a cover member that protects the distal end of the reinforcing cord 42C, and is a rigid step reducing member that reduces a rigid step at the distal end of the resin-coated cord 42. In FIG. 2, illustration of the protection member 70 is omitted.

  The protection member 70 is formed using the same resin as the coating resin 42S, and extends along the tire circumferential direction (the direction of the arrow S). The cross-sectional shape of the protection 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 protection member according to the embodiment of the present invention can have various shapes. As an example, the protection member may be shaped such that the tire radial dimension gradually decreases toward the tip in the tire circumferential direction, such as the protection member 72 shown in FIGS. 5A and 5B. The inclined surface 72S is inclined toward the carcass 16. Note that the “shape in which the tire radial dimension gradually decreases” may be a curved shape, a stepped shape, or the like, in addition to the linear shape shown in FIG.

  Further, the protection member 72 has a shape in which the tire radial dimension gradually decreases in the entire tire circumferential direction. However, the tire radial direction dimension may be gradually reduced only at least at the tip in the circumferential direction.

  As another example, the protection member may have a shape in which the dimension in the tire width direction gradually decreases toward the tip in the tire circumferential direction, as in a protection 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 size in the tire width direction gradually decreases” may be a curved shape, a stepped shape, or the like, in addition to the linear shape shown in FIG.

  Further, the protection member 74 has a shape in which the dimension in the tire width direction gradually decreases in the entire tire circumferential direction. However, the dimension in the tire width direction only needs to be gradually reduced at least only at the tip in the circumferential direction.

  As another example, the protection member has a shape in which the tire radial dimension and the tire width dimension gradually decrease toward the tip in the tire circumferential direction, as in a protective member 76 shown in FIGS. 7A and 7B. Is also good. The two inclined surfaces 76S are respectively inclined toward the carcass 16 or the resin-coated cord 42 adjacent in the tire width direction. Note that 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.

(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 portion that comes into contact with the road surface during traveling, and 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 in accordance with the required performance of the tire 10 such as drainage performance and steering stability.

(Action / Effect)
In the tire 10 according to the embodiment of the present invention, the resin belt 42 is formed by spirally winding the resin-coated cord 42 formed by coating the reinforcing cord 42C with the coating resin 42S in the tire circumferential direction. . A protection member 70 made of resin is fused to the distal 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 the resin, it is hard to rust. Further, it is possible to suppress the penetration of moisture into the inside of the resin-coated cord 42 along the reinforcing cord 42C from the tip end surface 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 inside the protective member 70. For this reason, the rigidity of the protection member 70 is lower than that of the resin-coated cord 42. Thereby, as shown in FIG. 4C, the rigidity in the tire circumferential direction near the tip surfaces 42E1 and 42E2 (tip portion) of the resin-coated cord 42 can be suppressed from suddenly changing around the tip 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 of the outermost resin-coated cord 42 in the tire width direction at the cross-sectional position where the reinforcing cord 42C passes. The same applies to FIGS. 5 (C), 8 (C), (D), 9 (C), and 9 (D) described later.

  When the protective member 72 shown in FIGS. 5A and 5B is used in place of the protective member 70, the protective member 72 gradually decreases in the tire radial direction toward the front end in the tire circumferential direction. As shown in (C), the rigidity in the tire circumferential direction also decreases gradually. As a result, the effect of reducing the rigidity step can be enhanced. Further, even if a protection member 74 (see FIGS. 6A and 6B) and a protection member 76 (see FIGS. 7A and 7B) are used instead of the protection member 70, the effect of reducing the rigidity step can be obtained. be able to.

<Second embodiment>
In the first embodiment, the distal end surfaces 42E1 and 42E2 of the resin-coated cord 42 are surfaces that are along the tire width direction and the radial direction, and are surfaces that are substantially perpendicular to the tire circumferential direction. As shown in FIGS. 8 (A) and (B), the resin-coated cord 42A has front end surfaces 42AE1 and 42AE2 inclined at an angle of less than 90 ° with respect to the tire circumferential direction and the radial direction. The tip surfaces 42AE1 and 42AE2 are inclined toward the carcass 16. That is, the resin-coated cord has a shape in which the tire radial dimension at the tip portion gradually decreases toward the tip in the tire circumferential direction. The “shape in which the tire radial dimension gradually decreases” may be a straight line, a curved line, or the like.

  The protection member fused to the front end surfaces 42AE1 and 42AE2 of the resin-coated cord 42A having a shape whose diameter in the tire radial direction gradually decreases toward the front end in the tire circumferential direction may be, for example, the protection member 70A. Similar to the protective member 70, the cross-sectional shape of the protection member 70 </ b> A along the tire width direction and the radial direction at the distal end portion is substantially equal to the cross-sectional shape of the resin-coated cord 42.

  Even if the resin-coated cord 42A and the protection member 70A are used, the rigidity step in the tire circumferential direction can be reduced as shown in FIG. The protection 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 effect of reducing the rigidity step can be enhanced.

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

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

  As a further example, the protection member fused to the front end surfaces 42AE1 and 42AE2 of the resin-coated cord 42A can be a protection member 74A as shown in FIGS. 10 (A) and 10 (B). Like the protection member 74, the protection member 74A has a shape in which the size in the tire width direction at the tip portion gradually decreases toward the tip in the tire circumferential direction.

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

<Third embodiment>
In the first embodiment, the distal end surfaces 42E1 and 42E2 of the resin-coated cord 42 are surfaces along the tire width direction and the radial direction, and are approximately perpendicular to the tire circumferential direction. As shown in FIGS. 12 (A) and 12 (B), the resin-coated cord 42B has the tip surfaces 42BE1 and 42BE2 inclined at an angle of less than 90 ° with respect to the tire circumferential direction. 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 at the tip portion gradually decreases toward the tip in the tire circumferential direction.

  The protection member fused to the front end surfaces 42BE1 and 42BE2 of the resin-coated cord 42B whose tire width direction dimension gradually decreases toward the front end in the tire circumferential direction may be, for example, the protection member 70B. Similar to the protective member 70, the protective member 70B has a cross-sectional shape along the tire width direction and the radial direction substantially equal to the cross-sectional shape of the resin-coated cord 42.

  As another example, the protection member that fuses to the distal end surfaces 42BE1 and 42BE2 of the resin-coated cord 42B can be a protection member 72B as shown in FIGS. 13A and 13B. The protection member 72 </ b> B, like the protection member 72, has a shape in which the size in the tire radial direction at the tip portion gradually decreases toward the tip in the tire circumferential direction.

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

  As yet another example, the protection member fused to the front end surfaces 42BE1 and 42BE2 of the resin-coated cord 42B can be a protection member 76B as shown in FIGS. 15A and 15B. The protection member 76 </ b> B, like the protection member 76, has a shape in which the size in the tire radial direction and the size in the tire width direction at the tip end gradually decrease toward the tip in the tire circumferential direction.

<Other embodiments>
The resin-coated cord 42A in the second embodiment has a shape in which the tire radial dimension at the tip portion gradually decreases toward the tip in the tire circumferential direction, and the resin-coated cord 42B in the third embodiment has a tire width direction at the tip portion. Although the dimensions have a shape that gradually decreases toward the tip in the tire circumferential direction, embodiments of the present invention are not limited to this.

  For example, as shown in FIGS. 16 (A) and 16 (B), both the tire radial direction dimension and the tire width direction dimension gradually decrease toward the tip in the tire circumferential direction, such as the tip surfaces 42DE1 and 42DE2 in the resin-coated cord 42D. Is also good. Each of the above embodiments can be applied to the protection member that is fused to the distal end surfaces 42DE1 and 42DE2.

  In each of the above embodiments, as shown in FIG. 3 (A), the resin belt layer 40 has a substantially square resin coating code 42 formed by coating one reinforcing cord 42C with a coating resin 42S. However, the embodiment of the present invention is not limited to this.

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

  In this case, as the shape of the distal end surface of the resin-coated cord 44, each shape shown in each of the above embodiments can be applied. Further, as shown in FIGS. 17A and 17B, of the reinforcement cords 44C, the reinforcement cords 44C arranged outside in the tire width direction are formed shorter than the reinforcement cords 44C arranged inside the tire width direction. Alternatively, the end surfaces 44E1 and 44E2 may be formed stepwise so that the end surfaces of the reinforcing cords 44C are exposed.

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

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

  In each of the above-described embodiments, the bead core 12A shown in FIG. 1 is described as a wire bundle, but 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.

  The resin-coated cord 46 can be configured by coating one or a plurality of reinforcing cords 46C with a coating resin 46S, but in the present embodiment, as an example, as shown in FIG. Is coated with a coating resin 46S. As shown in FIG. 20A, the resin-coated cord 46 is disposed so as to be wound about three times in the tire circumferential direction. The coating resins 46S adjacent to each other in the tire radial direction are joined by fusion. Thereby, a bead core 12A in which the reinforcing cord 46C is covered with the covering resin 46S is formed. The number of turns of the resin-coated cord 46 (three in this embodiment) and the number of reinforcing cords 46C disposed per turn (three in this embodiment) can be appropriately increased or decreased according to the purpose. .

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

  Further, the tip surfaces 46E1 and 46E2 are formed along the tire radial direction in FIG. 20, but the embodiment of the present invention is not limited to this, and the shapes of the tip surfaces 46E1 and 46E2 may be appropriately changed. it can.

  When the bead core 12A is formed of the resin-coated cord 46 and the protection member is fused to the distal end surfaces 46E1 and 46E2 of the resin-coated cord 46, the distal end surfaces 42E1 and 42E2 of the resin-coated cord 42 in the resin belt layer 40 are provided. However, it is not always necessary to provide a protection member such as the protection member 70. Furthermore, it is not always necessary to provide the resin belt layer 40 as a belt layer provided outside the carcass 16 in the tire radial direction, 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 invention, at least one of the belt layer and the bead core 12A may be configured to include the resin-coated cord and the protection member. Thus, the present invention can be implemented in various aspects.

10: tire (pneumatic tire), 12A: bead core, 16: carcass,
40: resin belt layer, 42: resin-coated cord, 42A: resin-coated cord,
42B: Resin-coated cord, 42D: Resin-coated cord,
42C: reinforcement cord (cord), 42S: coating resin (resin), 42E1: tip surface,
42E2: Tip surface, 42AE1: Tip surface, 42AE2: Tip surface,
42BE1 ... tip surface, 42BE2 ... tip surface, 42DE1 ... tip surface,
42DE2: tip end face, 44: resin-coated cord, 44C: reinforcing cord (cord),
44S: coating resin (resin), 44E1: tip surface, 44E2: tip surface,
46: resin-coated cord, 46C: reinforcing cord (cord),
46S: coating resin (resin); 46E1: tip surface; 46E2: tip surface;
70: Protective member, 70A: Protective member, 70B: Protective member, 72: Protective member,
72A: Protective member, 72B: Protective member, 74: Protective member,
74A: Protective member, 74B: Protective member, 76: Protective member, 76A: Protective member,
76B: Protective member, 78: Protective member

Claims (5)

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