JP2019209720A - Pneumatic tire - Google Patents

Abstract

To provide a pneumatic tire capable of alleviating a step between a resin reinforcement layer and a rubber belt layer.SOLUTION: An objective pneumatic tire 10 comprises: a carcass ply 14 formed straddling between a pair of bead cores 12A; a rubber belt layer 40 disposed outside the carcass ply 14 in a tire radial direction and formed by covering a cord with a rubber; a resin reinforcement layer 50 disposed adjacently to the outside of the rubber belt layer 40 in the tire radial direction and having an end part in a tire width direction formed inside the layer 40 in the tire width direction; and a resin-made step relaxation member 70 arranged at the end part of the rein reinforcement layer 50 in the tire width direction.SELECTED DRAWING: Figure 1

Description

  The present invention relates to a pneumatic tire.

  The following Patent Document 1 describes a passenger car tire in which a reinforcing element formed of a steel cord is arranged on the outer side in the tire radial direction of the carcass. In this passenger car tire, a central circumferential reinforcing element formed of a thermoplastic polymer film is disposed outside the reinforcing element in the tire radial direction.

JP, 2006-193725, A

  In the passenger car tire described in Patent Document 1, the central circumferential reinforcing element is formed of a thermoplastic polymer film. In general, the melting point of the thermoplastic polymer is higher than the melting point of the rubber, so that it is difficult to be deformed at the time of vulcanizing the tire and maintains the shape before vulcanization. For this reason, a level | step difference arises between the rubber | gum which coat | covers a steel cord, and a center circumferential direction reinforcement element, and an air pocket may arise in the entrance corner part formed by this level | step difference.

  In view of the above facts, an object of the present invention is to provide a pneumatic tire that can relieve a step between a resin reinforcing layer and a rubber belt layer.

  The pneumatic tire according to claim 1 is a carcass formed across a pair of bead cores, a rubber belt layer disposed on the outer side in the tire radial direction of the carcass and formed by covering a cord with rubber, and the rubber belt layer. A resin reinforcing layer disposed adjacent to the outer side in the tire radial direction and having an end in the tire width direction formed on the inner side in the tire width direction from the end in the tire width direction of the rubber belt layer; and the end in the tire width direction of the resin reinforcing layer And a step difference reducing member made of resin disposed in the portion.

  According to the pneumatic tire of claim 1, the end portion in the tire width direction of the resin reinforcing layer is formed on the inner side in the tire width direction from the end portion in the tire width direction of the rubber belt layer. That is, the rubber belt layer is formed wider than the resin reinforcing layer. For this reason, a step is generated between the resin reinforcing layer and the outer surface in the tire radial direction of the rubber belt layer.

  In the pneumatic tire according to claim 1, the step difference member made of resin is disposed at the end of the resin reinforcing layer in the tire width direction. For this reason, the level difference is eased and becomes gentle. For this reason, stress concentration hardly occurs during traveling. Moreover, it is hard to produce an air pocket in the entrance corner part formed by the level | step difference.

  A pneumatic tire according to claim 2 is a carcass formed across a pair of bead cores, a rubber belt layer disposed on the outer side in the tire radial direction of the carcass and formed by covering a cord with rubber, and the rubber belt layer. A resin reinforcing layer disposed adjacent to the outer side or the inner side in the tire radial direction and having an end portion in the tire width direction formed on the outer side in the tire width direction from the end portion in the tire width direction of the rubber belt layer; and the tire width direction of the rubber belt layer And a step difference reducing member made of resin disposed at the end.

  According to the pneumatic tire of the second aspect, the end portion in the tire width direction of the resin reinforcing layer is formed outside the end portion in the tire width direction of the rubber belt layer. That is, the resin reinforcing layer is formed wider than the rubber belt layer. For this reason, a level | step difference arises between the rubber-belt layer and the tire radial direction outer side surface or inner surface of a resin reinforcement layer.

  In the pneumatic tire of the second aspect, the step difference member made of resin is disposed at the end of the rubber belt layer in the tire width direction. For this reason, the flow of rubber during vulcanization is suppressed, and the dimensional stability of the cord is increased. Further, since the step is relaxed and becomes gentle, it is difficult for an air reservoir to form at the corner formed by the step.

  In the pneumatic tire according to a third aspect, the resin reinforcing layer is disposed on the inner side in the tire radial direction of the rubber belt layer, and is formed integrally with the step reducing member.

  According to the pneumatic tire of the third aspect, the rubber belt layer is disposed on the outer side in the tire radial direction of the resin reinforcing layer in which the step reducing member is integrally formed. For this reason, the rubber belt layer can be positioned and disposed between the leveling member. Thereby, compared with the case where a level | step difference mitigating member and a resin reinforcement layer are formed in a different body, a rubber belt layer can be arrange | positioned in an exact position.

  In the pneumatic tire according to a fourth aspect, the cord is inclined with respect to the tire circumferential direction, and both end portions in the longitudinal direction are located at both end portions in the tire width direction of the rubber belt layer.

  According to the pneumatic tire of the fourth aspect, the end portions of the cords are located at both ends of the rubber belt layer in the tire width direction. For this reason, for example, if the end portion in the tire width direction of the rubber belt layer is disposed adjacent to the tread rubber, the tread rubber may be damaged by the end portion of the cord. However, resin leveling members are disposed at both ends of the rubber belt layer in the tire width direction. As a result, the tread rubber is protected and hardly damaged.

  According to the pneumatic tire of the present invention, the step between the resin reinforcing layer and the rubber belt layer can be relaxed.

1 is a half sectional view showing a pneumatic tire according to a first embodiment of the present invention. It is the perspective view which showed an example of the rubber belt layer in the pneumatic tire which concerns on 1st Embodiment of this invention. (A) is sectional drawing which shows the level | step difference mitigation member in the pneumatic tire which concerns on 1st Embodiment of this invention, (B) is a cross section which shows the modification which formed the level | step difference mitigation member and the resin reinforcement layer integrally. FIG. It is a half sectional view showing a pneumatic tire according to a second embodiment of the present invention. It is sectional drawing which shows the level | step difference mitigation member in the pneumatic tire which concerns on 2nd Embodiment of this invention. (A) is a partial expanded sectional view which shows the modification which made the tire radial direction outer side surface concave in the tire radial direction inside the level | step difference mitigation member in the pneumatic tire which concerns on embodiment of this invention, (B ) Is a partially enlarged sectional view showing a modified example in which the outer surface in the tire radial direction is a planar shape, and (C) is a partially enlarged sectional view showing a modified example in which the outer surface in the tire radial direction is formed of a convex surface and a flat surface. It is a half sectional view showing a pneumatic tire according to a third embodiment of the present invention. (A) is sectional drawing which shows the level | step difference mitigation member in the pneumatic tire which concerns on 3rd Embodiment of this invention, (B) is a cross section which shows the modification which formed the level | step difference mitigation member and the resin reinforcement layer integrally. FIG. (A) is the expanded view which showed an example of the rubber belt layer in the pneumatic tire which concerns on 3rd Embodiment of this invention, (B) is the BB sectional drawing of (A).

<First Embodiment>
FIG. 1 shows a cut surface (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 invention. One side of the cross section viewed from the direction 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 rubber belt layer 40 that is provided on the outer side in the tire radial direction of the carcass ply 14, and an outer side in the tire radial direction of the rubber belt layer 40. And a tread 60 provided outside the resin reinforcing layer 50 in the tire radial direction. In FIG. 1, only the bead portion 12 on one side is shown.

(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 shape or a polygonal cross section. For example, a hexagonal shape can be adopted as the polygonal shape, but in the present embodiment, the bead core 12A has a rectangular shape.

  A bead filler 12B extending from the bead core 12A to the outer side in the tire radial direction and gradually decreasing in thickness toward the outer side in the tire radial direction is embedded in an area surrounded by the carcass ply 14 that is locked to the bead core 12A in the bead portion 12. ing. 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.

(Rubber belt layer)
A rubber 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 rubber belt layer 40 has a ring-shaped ridge formed by a single rubber-coated cord 42 spirally wound around the outer circumferential surface of the carcass 16 in the tire circumferential direction. Both end portions 42E1 and 42E2 of the rubber-coated cord 42 are arranged at different positions in the tire circumferential direction. Note that “spiral” indicates a state in which one rubber-coated cord 42 is wound at least one turn around the carcass 16.

  The rubber-coated cord 42 is configured by covering a reinforcing cord 42C with a coated rubber 42S, and has a substantially square cross section. The covering rubber 42 </ b> S is closely bonded to the outer peripheral surface of the carcass 16 by an adhesive or vulcanization adhesion.

  Further, the covering rubbers 42S adjacent to each other in the tire width direction are joined by vulcanization adhesion at the time of tire vulcanization. Thereby, a rubber belt layer 40 (rubber-coated belt layer) in which the reinforcing cord 42C is covered with the covering rubber 42S is formed.

  The reinforcing cord 42C in the rubber 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 rubber 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. The upper limit of the width BW of the rubber belt layer 40 is preferably 110% with respect to the ground contact width TW.

  Here, the contact width TW of the tread 60 means that the tire 10 is mounted on a standard rim prescribed in JATMA YEAR BOOK (2018 edition, Japan Automobile Tire Association Standard), and applicable size / prior rating in JATMA YEAR BOOK. Filled with 100% internal pressure of the air pressure (maximum air pressure) corresponding to the maximum load capacity (internal pressure-load capacity correspondence table in bold), so that the axis of rotation is parallel to the horizontal plate in a stationary state When placed and added mass corresponding to maximum load capacity. When the TRA standard or ETRTO standard is applied at the place of use or manufacturing, the respective standards are followed.

  The embodiment of the present invention is not limited to this, and as the reinforcing cord 42C in the rubber 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. Furthermore, a cord in which filaments of different materials are twisted can be adopted, 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.

(Resin reinforcement layer)
As shown in FIG. 1, a resin reinforcing layer 50 is disposed outside the rubber belt layer 40 in the tire radial direction. The resin reinforcing layer 50 is a rigidity imparting member in the tire 10. An end portion 50EW in the tire width direction of the resin reinforcing layer 50 (hereinafter simply referred to as an end portion 50EW) is disposed on the inner side in the tire width direction from the end portion 40EW in the width direction of the rubber belt layer 40. Further, the end 50EW is disposed on the outer side in the tire width direction from the circumferential groove 62 disposed on the outermost side in the tire width direction among the plurality of circumferential grooves 62 formed on the tread 60.

  The rubber belt layer 40 and the resin reinforcing layer 50, and the resin reinforcing layer 50 and the tread 60 are integrated by an adhesive or vulcanization adhesion.

  The resin material used for the resin reinforcing layer 50 is a thermoplastic resin. However, the embodiment of the present invention is not limited to this, and examples of the resin material include thermoplastic elastomers, thermosetting resins, (meth) acrylic resins, EVA resins, vinyl chloride resins, fluorine resins, silicone resins, and the like. In addition to general-purpose resins, engineering plastics (including super engineering plastics) can be used. The resin material here does not include vulcanized rubber.

  A thermoplastic resin (including a thermoplastic elastomer) refers to a high molecular 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-based thermoplastic resin, polystyrene-based thermoplastic resin, polyamide-based thermoplastic resin, polyester-based thermoplastic resin, etc. Can be mentioned.

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

(Step relief member)
As shown in FIG. 3A, a step having a height H <b> 1 corresponding to the thickness of the resin reinforcing layer 50 is formed between the resin reinforcing layer 50 and the rubber belt layer 40. Further, a resin-made level difference reducing member 70 is disposed at the end 50EW of the resin reinforcing layer 50. The level | step difference mitigation member 70 is a buffer material for smoothing the level | step difference of height H1, and is each arrange | positioned at the edge part 50EW of the tire width direction both sides.

  The step reducing member 70 has an end portion 50EW and an outer side surface 40E so as to fill a corner V1 where the end portion 50EW intersects the tire radial direction outer side surface 40E (hereinafter simply referred to as the outer side surface 40E) of the rubber belt layer 40. It is arranged to touch. The step reducing member 70 is joined to the end portion 50EW by an adhesive or heat welding, and is joined to the outer surface 40E by an adhesive or vulcanization adhesion.

  The step reducing member 70 is formed so that the thickness gradually decreases from the inner end in the tire width direction, which is substantially the same height as the end portion 50EW, toward the outer side in the tire width direction. Specifically, in the level difference mitigating member 70, the surface not in contact with the end portion 50EW and the outer side surface 40E is formed in a substantially arc shape that is convex toward the outer side in the tire radial direction and the outer side in the tire width direction.

  Further, the step alleviating member 70 extends in the tire circumferential direction (the front-rear direction in FIG. 3A) along the end 50EW, and is wound around the tire circumferential direction by one turn.

(tread)
As shown in FIG. 1, a tread 60 is provided outside the resin reinforcing layer 50 in the tire radial direction. The tread 60 is a part that contacts 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 according to the performance such as drainage performance and steering stability required for the tire 10.

(Action / Effect)
In the tire 10 according to the embodiment of the present invention, as shown in FIG. 3 (A), a step difference member 70 made of resin is disposed at the end 50EW of the resin reinforcing layer 50.

  The step reducing member 70 is disposed so as to contact the end 50EW and the outer surface 40E so as to fill the corner V1 where the end 50EW of the resin reinforcing layer 50 and the outer surface 40E of the rubber belt layer 40 intersect. . Thereby, an air pocket is hard to produce in the entrance corner part V1.

  Moreover, the level | step difference mitigation member 70 is formed so that thickness may reduce gradually toward the tire width direction outer side. For this reason, the step of the height H1 formed between the resin reinforcing layer 50 and the rubber belt layer 40 is relaxed, and is formed more gently than in the case where the step relief member 70 is not provided.

  Further, the step reducing member 70 gradually decreases in thickness while forming a convex surface from the inner end in the tire width direction, which is substantially the same height as the end portion 50EW of the resin reinforcing layer 50, toward the outer side in the tire width direction and the outer side in the tire radial direction. It is formed to do. For this reason, the tire radial direction outer side surface 50 </ b> E of the resin reinforcing layer 50 is gently connected to the step reducing member 70. As a result, the rigidity step near the outer surface 50E is relaxed, and stress concentration is less likely to occur during travel.

  In addition, in this embodiment, although the resin reinforcement layer 50 and the level | step difference mitigation member 70 were formed by another member, embodiment of this invention is not restricted to this. For example, as shown in FIG. 3B, the resin reinforcing layer 50 and the step reducing member 70 may be integrally formed. By integrally forming the resin reinforcing layer 50 and the step reducing member 70, the number of parts of the pneumatic tire 10 is reduced and the manufacturing efficiency is improved.

Second Embodiment
(Constitution)
In the first embodiment, the end portion 50EW of the resin reinforcing layer 50 is disposed on the inner side in the tire width direction than the width direction end portion 40EW of the rubber belt layer 40. In the second embodiment, as shown in FIG. Further, the end portion 52EW in the width direction of the resin reinforcing layer 52 is disposed outside the end portion 44EW in the tire width direction of the rubber belt layer 44 (hereinafter simply referred to as the end portion 44EW) in the tire width direction.

  In this case, as shown in FIG. 5, a step having a height H <b> 2 corresponding to the thickness of the rubber belt layer 44 is formed between the resin reinforcing layer 52 and the rubber belt layer 44. And the resin level | step difference mitigation member 72 is arrange | positioned at the edge part 44EW of the rubber belt layer 44. FIG. The step reducing members 72 are respectively disposed at the end portions 44EW of the rubber belt layer 44 on both sides in the tire width direction.

  The level difference reducing member 72 has an end portion 44EW so as to fill a corner portion V2 where the end portion 44EW and a tire radial direction inner side surface 52W (hereinafter simply referred to as an inner side surface 52W) of the resin reinforcing layer 52 intersect. And it arrange | positions so that the inner surface 52W may be contact | connected. The step reducing member 72 is joined to the end portion 44EW by an adhesive or vulcanization adhesion, and joined to the inner side surface 52W by an adhesive or heat welding.

  The step reducing member 72 is formed so that the thickness gradually decreases from the inner end in the tire width direction, which is substantially the same height as the end portion 44EW, toward the outer side in the tire width direction. Specifically, a substantially circular shape that protrudes outward in the tire radial direction toward the outer side in the tire width direction so that the outer side surface in the tire radial direction of the step reducing member 72 is in contact with the inner radial side surface 52W of the resin reinforcing layer 52. It is formed by changing the curvature from an arc shape to a concave shape inward in the tire radial direction.

  The configuration of the rubber belt layer 44 is the same as that of a rubber belt layer 90 (see FIGS. 9A and 9B) described later, and detailed description thereof will be omitted. It is formed by a rubber-coated ply formed by coating an inclined reinforcing cord with a coated rubber.

(Action / Effect)
With the above-described configuration, in the second embodiment, the step of the height H2 is gently relaxed by the step mitigating member 72, and air is not easily trapped in the entrance corner V2. Furthermore, since the step easing member 72 is formed so that the outer side surface in the tire radial direction is in contact with the inner side surface 52W in the tire radial direction of the resin reinforcing layer 52, the effect of preventing air accumulation is enhanced.

  In addition to the step reducing member 70 in the first embodiment and the step reducing member 72 in the second embodiment, the shape of the step reducing member is such that the thickness gradually decreases from the inner end in the tire width direction toward the outer side in the tire width direction. If it is formed, it can be set arbitrarily.

  For example, as in the step reducing member 74 shown in FIG. 6A, the outer surface in the tire radial direction can be formed in a shape that is concave from the inner side in the tire width direction to the inner side in the tire radial direction.

  Moreover, you may form a tire radial direction outer side surface planarly (straight shape in sectional view) like the level | step difference mitigation member 76 shown to FIG. 6 (B).

  Or like the level | step difference mitigation member 78 shown in FIG.6 (C), it changes so that a tire radial direction outer surface may be planarly changed from the shape which protrudes in the tire radial direction outer side toward the outer side from a tire width direction inner side. It may be formed.

<Third Embodiment>
(Constitution)
In the first and second embodiments, the resin reinforcing layers 50 and 52 are disposed on the outer side in the tire radial direction of the rubber belt layers 40 and 44. However, as shown in FIG. A rubber belt layer 90 is disposed outside the reinforcing layer 54 in the tire radial direction.

  As shown in FIG. 8A, a step having a height H3 corresponding to the thickness of the rubber belt layer 90 is formed between the rubber belt layer 90 and the resin reinforcing layer 54. Further, a step difference member 80 made of resin is disposed at the end portion 90EW in the tire width direction of the rubber belt layer 90 (hereinafter simply referred to as the end portion 90EW). The step alleviating member 80 is disposed at each end 90EW of the rubber belt layer 90 on both sides in the tire width direction.

  The step reducing member 80 has an end portion 90EW and an outer surface so as to fill a corner V3 where the end portion 90EW intersects the tire radial direction outer surface 54E (hereinafter simply referred to as the outer surface 54E) of the resin reinforcing layer 54. 54E is arranged in contact with 54E. The step reducing member 80 is bonded to the outer surface 54E by an adhesive or heat welding, and is bonded to the end 90EW by an adhesive or vulcanization bonding.

  The step reducing member 80 is formed so that the thickness gradually decreases from the inner end in the tire width direction, which is substantially the same height as the end portion 90EW, toward the outer side in the tire width direction. Specifically, in the step reducing member 80, the surface not in contact with the end portion 90EW and the outer surface 54E is formed in a substantially arc shape that is convex toward the outer side in the tire radial direction and the outer side in the tire width direction.

  FIG. 9A shows a development view of the rubber belt layer 90. The rubber belt layer 90 is formed by covering a reinforcing cord 92C inclined with respect to the tire circumferential direction (the direction indicated by the arrow S in FIG. 9A) with a covering rubber 92S (see FIG. 9B ))). In a state where the rubber belt layer 90 is wound around the tire, the end surface 92A of the rubber-coated ply 92 shown at the bottom of FIG. 9A and the end surface 92B of the rubber-coated ply 92 shown at the top are mutually connected. Glued.

Each reinforcing cord 92C is laid between both end portions 90EW of the rubber belt layer 90 in the tire width direction. In other words, both ends of the reinforcing cord 92C are positioned at both end portions 90EW of the rubber belt layer 90 in the tire width direction.
Thus, the end surface of the reinforcing cord 92C is exposed at the tire width direction end portion 90EW of the rubber belt layer 90. The rubber-coated ply 92 may be formed by coating a rubber-coated cord by covering an arbitrary number (for example, one or six) of reinforcing cords 92C with a coated rubber, and arranging the rubber-coated cords side by side.

(Action / Effect)
With the above configuration, in the third embodiment, as shown in FIG. 8A, the step of the height H2 is gently formed by the step reducing member 80, and an air pocket is generated in the entrance corner V3. hard. In addition, since the step relaxing member 80 prevents the covering rubber 92S forming the rubber belt layer 90 from damming and flowing during vulcanization, the dimensional stability of the rubber covering ply 92 is enhanced.

  Further, in the present embodiment, the reinforcing cords 92 </ b> C are disposed to be inclined with respect to the tire circumferential direction, and both end portions in the longitudinal direction are respectively positioned at both end portions 90 </ b> EW in the tire width direction of the rubber belt layer 90. If the tire width direction end portion 90EW of the rubber belt layer 90 is disposed adjacent to the rubber, the rubber may be damaged by the end portion of the reinforcing cord 92C. However, in the present embodiment, the step difference reducing member 80 made of resin is disposed at both ends 90EW in the tire width direction of the rubber belt layer 90. Thereby, since the surrounding rubber (rubber forming the tread 60) is protected, it is hard to be damaged.

  In this embodiment, the step reducing member 80 is formed separately from the resin reinforcing layer 54 and is bonded to the outer surface 54E of the resin reinforcing layer 54 by an adhesive or heat welding. The embodiment is not limited to this. For example, as shown in FIG. 8B, the step reducing member 80 and the resin reinforcing layer 54 may be integrally formed.

  Accordingly, the rubber belt layer 90 is disposed on the outer side in the tire radial direction of the resin reinforcing layer 54 in which the step reducing member 80 is integrally formed. For this reason, the rubber belt layer 90 can be disposed between the step relief members 80 when the rubber belt layer 90 is formed. Thereby, compared with the case where the level | step difference mitigation member 80 and the resin reinforcement layer 54 are formed in a different body, the rubber belt layer 90 can be arrange | positioned in an exact position.

  Moreover, the level | step difference mitigation member 70,72,74,76,78,80 which concerns on embodiment of this invention may be formed separately from the resin reinforcement layer 50 which contacts, and may be formed integrally.

  The rubber belt layer 40 in the first embodiment may be replaced with the rubber belt layer 90 in the third embodiment, and the rubber belt layers 44 and 90 in the second and third embodiments may be replaced with the rubber belt layer 40. That is, the step reducing member in the present invention can be employed regardless of the shape of the rubber belt layer. As described above, the present invention can be implemented in various modes.

10 ... tyre (pneumatic tire), 14 ... carcass, 12A ... bead core,
40, 44, 90 ... rubber belt layer, 42C ... reinforcement cord (cord),
42S ... Covering rubber (rubber) 50, 52, 54 ... Resin reinforcement layer, 60 ... Tread,
70, 72, 74, 76, 78, 80 ... Step relief member

Claims (4)

A carcass formed across a pair of bead cores;
A rubber belt layer disposed outside the carcass in the tire radial direction and formed by covering a cord with rubber;
A resin reinforcing layer disposed adjacent to the outer side in the tire radial direction of the rubber belt layer and having an end in the tire width direction formed on the inner side in the tire width direction from the end in the tire width direction of the rubber belt layer;
A step relief member made of resin disposed at an end of the resin reinforcing layer in the tire width direction; and
Pneumatic tire with A carcass formed across a pair of bead cores;
A rubber belt layer disposed outside the carcass in the tire radial direction and formed by covering a cord with rubber;
A resin reinforcing layer disposed adjacent to the outer side or the inner side in the tire radial direction of the rubber belt layer, the tire width direction end portion being formed on the tire width direction outer side from the tire width direction end portion of the rubber belt layer;
A step relief member made of resin disposed at an end in the tire width direction of the rubber belt layer;
Pneumatic tire with   The pneumatic tire according to claim 2, wherein the resin reinforcing layer is disposed on an inner side in the tire radial direction of the rubber belt layer and is formed integrally with the step reducing member.   4. The pneumatic tire according to claim 2, wherein the cord is disposed to be inclined with respect to the tire circumferential direction, and both end portions in the longitudinal direction are located at both end portions in the tire width direction of the rubber belt layer, respectively. .