WO2021117425A1 - Run-flat tire - Google Patents

Run-flat tire Download PDF

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Publication number
WO2021117425A1
WO2021117425A1 PCT/JP2020/042725 JP2020042725W WO2021117425A1 WO 2021117425 A1 WO2021117425 A1 WO 2021117425A1 JP 2020042725 W JP2020042725 W JP 2020042725W WO 2021117425 A1 WO2021117425 A1 WO 2021117425A1
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WO
WIPO (PCT)
Prior art keywords
tire
ply
rubber layer
reinforcing rubber
carcass ply
Prior art date
Application number
PCT/JP2020/042725
Other languages
French (fr)
Japanese (ja)
Inventor
祐介 乾
Original Assignee
Ｔｏｙｏ Ｔｉｒｅ株式会社
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by Ｔｏｙｏ Ｔｉｒｅ株式会社 filed Critical Ｔｏｙｏ Ｔｉｒｅ株式会社
Publication of WO2021117425A1 publication Critical patent/WO2021117425A1/en

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    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B60—VEHICLES IN GENERAL
    • B60C—VEHICLE TYRES; TYRE INFLATION; TYRE CHANGING; CONNECTING VALVES TO INFLATABLE ELASTIC BODIES IN GENERAL; DEVICES OR ARRANGEMENTS RELATED TO TYRES
    • B60C17/00—Tyres characterised by means enabling restricted operation in damaged or deflated condition; Accessories therefor
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B60—VEHICLES IN GENERAL
    • B60C—VEHICLE TYRES; TYRE INFLATION; TYRE CHANGING; CONNECTING VALVES TO INFLATABLE ELASTIC BODIES IN GENERAL; DEVICES OR ARRANGEMENTS RELATED TO TYRES
    • B60C9/00—Reinforcements or ply arrangement of pneumatic tyres
    • B60C9/02—Carcasses
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B60—VEHICLES IN GENERAL
    • B60C—VEHICLE TYRES; TYRE INFLATION; TYRE CHANGING; CONNECTING VALVES TO INFLATABLE ELASTIC BODIES IN GENERAL; DEVICES OR ARRANGEMENTS RELATED TO TYRES
    • B60C9/00—Reinforcements or ply arrangement of pneumatic tyres
    • B60C9/02—Carcasses
    • B60C9/04—Carcasses the reinforcing cords of each carcass ply arranged in a substantially parallel relationship
    • B60C9/08—Carcasses the reinforcing cords of each carcass ply arranged in a substantially parallel relationship the cords extend transversely from bead to bead, i.e. radial ply

Definitions

  • the present invention relates to a side-reinforced type run-flat tire in which a reinforcing rubber layer is arranged on the sidewall.
  • a side-reinforced type run-flat tire in which a reinforcing rubber layer is arranged on a sidewall is known.
  • This reinforcing rubber layer has a function of preventing the tire from being completely flattened even when the internal pressure of the tire is reduced. Therefore, by providing the run-flat tire with this reinforcing rubber layer, it is possible to perform run-flat running (running in a state where the internal pressure of the tire is reduced) for a certain distance.
  • one end side of a plurality of car cus plies is overlapped with the end portion of the belt layer.
  • Structural run-flat tires are disclosed.
  • Patent Document 2 describes a run-flat tire having a structure in which at least one carcass ply is separated under a belt layer in order to improve durability during run-flat running and riding comfort during normal internal pressure running. It is disclosed.
  • the present invention has been made in view of the above problems, and an object of the present invention is to provide a run-flat tire capable of reducing weight while ensuring steering stability.
  • the run-flat tire (for example, tire 1) of the present invention has a pair of beads (for example, beads 11) and a pair of sidewalls (for example, sidewalls) extending outward in the tire radial direction from each of the pair of beads. 12), a tread (for example, a tread 13) arranged between the pair of sidewalls, a carcass ply (for example, a carcass ply 23) bridged between the pair of beads, and the sidewall.
  • a reinforcing rubber layer (for example, a reinforcing rubber layer 50) arranged on the tire cavity side of the carcass ply is provided, and a belt (for example, a steel belt 26) is provided on the tire radial outer side of the carcass ply in the tread.
  • the carcass ply is arranged, and the carcass ply is composed of a plurality of layers of plies (for example, a first carcass ply 231 and a second carcass ply 232), and at least one layer of the plies of the plurality of layers (for example, a second carcass)
  • the ply 232) is a split carcass ply divided inside the tire radial direction of the belt, and the reinforcing rubber layer is formed inside the ply split end (for example, the ply split end 232A) of the split ply in the tire radial direction. It is a run-flat tire on which is placed.
  • the carcass ply is composed of two layers of plies (for example, first carcass ply 231 and second carcass ply 232), and among the two layers of plies. Only the ply on the belt side (for example, the second carcass ply 232) may be divided inside the tire radial direction of the belt.
  • the reinforcing rubber layer is located on the outer side of the first reinforcing rubber layer (for example, the first reinforcing rubber layer 501) and the first reinforcing rubber layer in the tire radial direction. It is composed of a second reinforcing rubber layer (for example, a second reinforcing rubber layer 502) arranged, and the inner side of the ply split end of the split ply in the tire radial direction and the outer end in the tire width direction of the belt (for example, the outer end in the tire width direction of the belt).
  • a second reinforcing rubber layer for example, a second reinforcing rubber layer 502
  • the second reinforcing rubber layer is arranged inside the outer end 26A in the tire width direction in the tire radial direction, and the hardness of the second reinforcing rubber layer is lower than the hardness of the first reinforcing rubber layer. You may.
  • the tire width direction of the outer end of the belt in the tire width direction and the outer end of the second reinforcing rubber layer in the tire width direction (for example, the outer end 502B in the tire width direction).
  • the distance L1 may be 10 mm or more.
  • the tire width direction distance L2 may be 10 mm or more.
  • the divided ply and the belt are arranged so as to partially overlap, and the ply divided end of the divided ply and the said belt.
  • the distance L3 in the tire width direction from the outer end of the belt in the tire width direction may be 10 mm or more.
  • FIG. 1 is a diagram showing a half cross section of a tire 1 which is a run-flat tire according to the present embodiment in the tire width direction. Since the basic structure of the tire 1 is symmetrical in the cross section in the tire width direction, the cross-sectional view of the right half is shown here.
  • reference numeral S1 is the tire equatorial plane.
  • the tire equatorial plane S1 is a plane orthogonal to the tire rotation axis (tire meridian) and is located at the center in the tire width direction.
  • the tire width direction is a direction parallel to the tire rotation axis, and is a paper surface left-right direction in the cross-sectional view of FIG.
  • the tire width direction X The inner side in the tire width direction is the direction approaching the tire equatorial plane S1, and is the left side of the paper surface in FIG.
  • the outside in the tire width direction is the direction away from the tire equatorial plane S1, and is the right side of the paper surface in FIG.
  • the tire radial direction is a direction perpendicular to the tire rotation axis, and is a vertical direction on the paper surface in FIG. In FIG. 1, it is shown as the tire radial direction Y.
  • the outer side in the tire radial direction is a direction away from the tire rotation axis, and in FIG. 1, it is the upper side of the paper surface.
  • the inside in the tire radial direction is a direction approaching the tire rotation axis, and in FIG. 1, it is the lower side of the paper surface.
  • the cross-sectional view of FIG. 1 is a cross-sectional view in the tire width direction (tire meridian cross-sectional view) in a no-load state in which a tire is mounted on a specified rim and filled with a specified internal pressure.
  • the specified rim refers to a standard rim defined by JATTA according to the tire size.
  • the specified internal pressure is, for example, 180 kPa when the tire is for a passenger car. The same applies to FIG. 2, which will be described later.
  • the tire 1 is, for example, a run-flat tire for a passenger car, and is a pair of beads 11 provided on both sides in the tire width direction, a sidewall 12 extending outward in the tire radial direction from each of the beads 11, and each of the sidewalls 12.
  • the tread 13 is provided so as to form a tread surface (contact patch with the road surface) 13C which is connected to the outer side in the tire radial direction.
  • the bead 11 includes a bead core 21 and a bead filler 22 extending outward in the tire radial direction of the bead core 21.
  • the bead core 21 is an annular member formed by winding a metal bead wire coated with rubber a plurality of times, and is a member that serves to fix an air-filled tire 1 to a wheel rim (not shown). is there.
  • the bead filler 22 is a rubber member having a tapered tip that extends outward in the tire radial direction of the bead core 21.
  • the bead filler 22 is a member provided for increasing the rigidity of the peripheral portion of the bead and ensuring high maneuverability and stability.
  • the bead filler 22 is made of rubber having a hardness higher than that of the surrounding rubber member, for example.
  • the carcass ply 23 constitutes a ply that serves as a skeleton of the tire 1, and is embedded in the tire 1 so as to pass between the pair of beads 11 and the pair of sidewalls 12 and the tread 13.
  • the carcass ply 23 includes a ply body 24 extending from one bead core 21 to the other bead core 21 and extending between the tread 13 and the bead 11, and a ply folded portion 25 folded around the bead core 21. .. In the present embodiment, the ply folded portion 25 is overlapped with the ply main body 24.
  • the carcass ply 23 is composed of a plurality of ply cords extending in the tire width direction. Further, the plurality of ply cords are arranged side by side in the tire circumferential direction. This ply cord is made of an insulating organic fiber cord such as polyester or polyamide, and is coated with a topping rubber.
  • the carcass ply 23 of the present embodiment is composed of two layers of carcass plies in which the first carcass ply 231 and the second carcass ply 232 are stacked. However, the carcass ply 23 may have a plurality of layers and may have three or more layers.
  • the bead 11 further includes a chaher 31 and a rim strip rubber 32 arranged on the outer side of the chaher 31 in the tire width direction.
  • the checker 31 is provided inside the carcass ply 23 provided around the bead core 21 in the tire radial direction.
  • the chaher 31 also extends to the outside of the ply folded portion 25 of the carcass ply 23 in the tire width direction.
  • the rim strip rubber 32 is arranged on the outer side of the chaher 31 and the carcass ply 23 in the tire width direction, and is a member that comes into contact with the rim (not shown) when the rim is mounted.
  • the sidewall 12 includes a reinforcing rubber layer 50 arranged inside the carcass ply 23 in the tire width direction, and a sidewall rubber 30 arranged outside the carcass ply 23 in the width direction.
  • the reinforcing rubber layer 50 is a side reinforcing rubber having a substantially crescent shape in a cross-sectional view in the tire width direction (cross-sectional view of the tire meridian).
  • the reinforcing rubber layer 50 has a function of preventing the tire 1 from being completely flattened even when the internal pressure of the tire 1 is reduced. Details of the reinforcing rubber layer 50 will be described later.
  • the sidewall rubber 30 is a rubber member that constitutes the outer wall surface of the tire 1.
  • the sidewall rubber 30 is a portion that bends most when the tire 1 acts as a cushion, and a flexible rubber having fatigue resistance is usually adopted.
  • the tread 13 is arranged on the tire radial outer side of the carcass ply 23, the cap ply 27 arranged on the tire radial outer side of the steel belt 26, and the tire radial outer side of the cap ply 27. It includes a tread rubber 28.
  • the steel belt 26 is composed of a plurality of steel cords coated with rubber. By providing the steel belt 26, the rigidity of the tire 1 is ensured, and the ground contact state between the tread 13 and the road surface is improved.
  • a steel belt having a two-layer structure inner steel belt 261 and outer steel belt 262
  • the number of stacked steel belts 26 is not limited to this.
  • the cap ply 27 is a member arranged on the outer side of the steel belt 26 in the tire radial direction, and has a function as a belt reinforcing layer.
  • the cap ply 27 is composed of an insulating organic fiber layer such as a polyamide fiber, and is covered with a topping rubber. By providing the cap ply 27, it is possible to improve the durability and reduce the road noise during traveling.
  • the outer end 27A of the cap ply 27 in the tire width direction extends outward in the tire width direction from the outer end 26A of the steel belt 26 in the tire width direction.
  • the inner steel belt 261 is wider than the outer steel belt 262, so that the outer end 26A of the steel belt 26 in the tire width direction is the tire of the inner steel belt 261. It consists of the outer edge in the width direction.
  • the tread rubber 28 is a member constituting the tread surface (contact patch with the road surface) 13C during normal traveling.
  • the tread 13C of the tread rubber 28 is provided with a tread pattern 13D composed of a plurality of grooves.
  • an inner liner 29 as a rubber layer constituting the inner wall surface of the tire 1 is provided on the tire lumen side of the carcass ply 23 and the reinforcing rubber layer 50.
  • the inner liner 29 mainly covers the inner surface of the carcass ply 23 in the tread 13, and mainly covers the inner surface of the reinforcing rubber layer 50 in the sidewall 12 and the bead 11.
  • the inner liner 29 is made of air-permeable rubber to prevent air in the tire lumen from leaking to the outside.
  • the sidewall rubber 30 of the sidewall 12 extends toward the tread 13.
  • the tread rubber 28 of the tread 13 extends toward the sidewall 12.
  • the tread rubber 28 and the sidewall rubber 30 are laminated on the outer surface side of the tire in a part of the carcass ply 23. More specifically, in the region where the sidewall rubber 30 and the tread rubber 28 coexist, that is, in the transition region between the sidewall 12 and the tread 13, the sidewall rubber 30 and the tread rubber are on the outer surface side of the tire of the carcass ply 23. 28 and 28 are stacked in this order.
  • the rim strip rubber 32 and the sidewall rubber 30 are laminated in order on the tire outer surface side of the carcass ply 23. Further, in the vicinity of this transition region, a rim protector 33 having a top portion 33A protruding outward in the tire width direction and continuously extending in an annular shape in the tire circumferential direction is provided.
  • the rim strip rubber 32 is provided with the top 33A of the rim protector 33.
  • the rim protector 33 has a function of protecting the rim (not shown) from trauma.
  • the reinforcing rubber layer 50 and the chaher 31 are laminated in this order on the tire lumen side of the carcass ply 23.
  • the inner liner 29 further covers the tire lumen side of these rubber members.
  • the chaher 31 and the reinforcing rubber layer 50 may be laminated in this order on the tire lumen side of the carcass ply 23, and the tire lumen side of these rubber members may be covered with the inner liner 29.
  • the tire 1 of the present embodiment has the pair of beads 11, the pair of sidewalls 12 extending outward in the tire radial direction from each of the pair of beads 11, and the tread 13 arranged between the pair of sidewalls 12.
  • a carcass ply 23 bridged between the pair of beads 11 and a reinforcing rubber layer 50 arranged on the tire lumen side of the carcass ply 23 on the sidewall 12 are provided.
  • a steel belt 26 as a belt is arranged on the outer side of the carcass ply 23 in the tire radial direction.
  • the carcass ply 23 is composed of a plurality of layers of plies (first carcass ply 231 and second carcass ply 232), and the ply of the plurality of layers.
  • at least one layer of ply is a split carcass ply that is divided inside the steel belt 26 in the tire radial direction.
  • the reinforcing rubber layer 50 is arranged inside the ply split end 232A of the split ply in the tire radial direction.
  • FIG. 2 is an enlarged cross-sectional view of the tire 1 of FIG. 1 around the boundary region between the sidewall 12 and the tread 13.
  • the carcass ply 23 of the present embodiment is composed of two layers of carcass plies in which the first carcass ply 231 and the second carcass ply 232 are stacked.
  • the second carcass ply 232 on the steel belt 26 side is divided inside the steel belt 26 in the tire radial direction.
  • the ply split end 232A of the second carcass ply 232 is located inside the tire width direction outer end 26A of the steel belt 26 in the tire width direction. Since the second carcass ply 232 is divided, the second carcass ply 232 does not exist inside the ply divided end 232A of the second carcass ply 232 in the tire width direction.
  • the reinforcing rubber layer 50 is composed of a first reinforcing rubber layer 501 and a second reinforcing rubber layer 502 arranged on the outer side of the first reinforcing rubber layer 501 in the tire radial direction.
  • the hardness of the second reinforcing rubber layer 502 is lower than that of the first reinforcing rubber layer 501.
  • the second reinforcing rubber layer 502 is arranged inside the tire radial direction of the ply split end 232A of the divided second carcass ply 232 and inside the tire radial direction of the tire width direction outer end 26A of the steel belt 26. ing.
  • Each member has a configuration in which the second reinforcing rubber layer 502, the first carcass ply 231 and the second carcass ply 232, and the steel belt 26 are laminated in this order from the inside in the tire radial direction to the outside in the tire radial direction. There is.
  • the direction distance L1 is preferably 10 mm or more.
  • the tire width direction distance L2 between the ply split end 232A of the divided second carcass ply 232 and the tire width direction inner end 502A of the second reinforcing rubber layer 502 is preferably 10 mm or more.
  • the divided second carcass ply 232 and the steel belt 26 are arranged so as to partially overlap each other, and the divided second carcass ply 232 ply split end 232A and the steel belt 26 in the tire width direction.
  • the distance L3 in the tire width direction from the outer end 26A is preferably 10 mm or more.
  • the rubber used for the bead filler 22 and the reinforcing rubber layer 50 at least a rubber having a hardness higher than that of the sidewall rubber 30 and the inner liner 29 is used.
  • the hardness of rubber is a value (durometer hardness) measured by a type A durometer in an atmosphere of 23 ° C. in accordance with JIS K6253.
  • the hardness of the bead filler 22 and the reinforcing rubber layer 50 is about 1.1 to 2.3 times the hardness of the sidewall rubber 30. More specifically, the hardness of the sidewall rubber 30 is in the range of 45 to 60 in the durometer hardness, whereas the hardness of the reinforcing rubber layer 50 is in the range of 70 to 100 in the durometer hardness. is there.
  • the hardness of the second reinforcing rubber layer 502 constituting the reinforcing rubber layer 50 is set lower than the hardness of the first reinforcing rubber layer 501.
  • the hardness of the first reinforcing rubber layer 501 is preferably 75 to 100 in terms of durometer hardness, and the hardness of the second reinforcing rubber layer 502 is lower than the hardness of the first reinforcing rubber layer 501.
  • the hardness of the durometer is preferably 70 to 85.
  • the hardness of the second reinforcing rubber layer 502 is set to the hardness of the first reinforcing rubber layer.
  • the second reinforcing rubber layer 502 effectively absorbs the stress concentration generated at the ply split end 232A, and the rigidity of the entire tire during run-flat running is increased by the entire reinforcing rubber layer 50. Can be secured.
  • the hardness of the second reinforcing rubber layer 502 is lower than the hardness of the first reinforcing rubber layer 501.
  • the second reinforcing rubber layer 502 effectively absorbs the stress concentration generated at the outer end 26A of the steel belt 26 in the tire width direction, and the rigidity of the entire tire during run flat running is increased by the entire reinforcing rubber layer 50. Can be secured.
  • the carcass ply 23 is composed of two layers of carcass ply, and of the two layers of carcass ply, only the second carcass ply 232 on the steel belt 26 side is a steel belt.
  • the configuration divided inside the tire radial direction of 26 is particularly preferable from the viewpoint of ensuring steering stability and weight reduction, but the configuration of the carcass ply 23 is not limited to this.
  • both the two-layer carcass ply may be divided inside the steel belt 26 in the tire radial direction.
  • only the first carcass ply 231 may be divided inside the steel belt 26 in the tire radial direction.
  • the carcass ply 23 is composed of three or more layers of plies, and at least one of the three or more layers of plies is a divided carcass ply divided inside the tire radial direction of the steel belt 26. It may be a configuration. Even in these cases, by arranging the reinforcing rubber layer 50 inside the split end of the split ply in the tire radial direction, it is possible to reduce the weight while ensuring steering stability.
  • the reinforcing rubber layer 50 is preferably composed of the first reinforcing rubber layer 501 and the second reinforcing rubber layer 502, but the reinforcing rubber layer 50 is one. It may be composed of a rubber member. Even in this case, by arranging the reinforcing rubber layer 50 inside the split end of the split ply in the tire radial direction, it is possible to reduce the weight while ensuring steering stability.
  • the tire 1 includes a pair of beads 11, a pair of sidewalls 12 extending outward in the tire radial direction from each of the pair of beads 11, and a tread 13 arranged between the pair of sidewalls 12.
  • a run-flat tire comprising a carcass ply 23 bridged between a pair of beads 11 and a reinforcing rubber layer 50 arranged on the tire cavity side of the carcass ply 23 on the sidewall 12.
  • a steel belt 26 is arranged outside the tire radial direction of the carcass ply 23, and the carcass ply 23 is composed of a plurality of layers of plies (first carcass ply 231 and second carcass ply 232), and the carcass ply 23 is composed of a plurality of layers of plies.
  • at least one ply is a split carcass ply divided inside the tire radial direction of the steel belt 26, and the reinforcing rubber layer 50 is arranged inside the tire radial direction at the ply split end of the divided ply. ing.
  • the split ply and arranging the reinforcing rubber layer at an appropriate position it is possible to reduce the weight while ensuring the steering stability.
  • the carcass ply 23 of the tire 1 according to the present embodiment is composed of two layers of plies (first carcass ply 231 and second carcass ply 232), and of the two layers of plies, the steel belt 26 side. Only the second carcass ply 232 of the above is divided inside the tire radial direction of the steel belt 26. In this way, of the two layers of ply, only the second carcass ply 232 on the steel belt 26 side is used as the split ply, and the reinforcing rubber layer is arranged at an appropriate position, thereby ensuring steering stability and being lightweight. It can be made more appropriate.
  • the reinforcing rubber layer 50 is composed of a first reinforcing rubber layer 501 and a second reinforcing rubber layer 502 arranged on the outer side of the first reinforcing rubber layer 501 in the tire radial direction.
  • the second reinforcing rubber layer 502 is arranged inside the tire radial direction of the ply split end 232A of the divided second carcass ply 232 and inside the tire radial direction of the tire width direction outer end 26A of the steel belt 26.
  • the hardness of the second reinforcing rubber layer 502 is lower than the hardness of the first reinforcing rubber layer 501.
  • the stress concentration generated at the ply split end 232A and the outer end 26A in the tire width direction of the steel belt 26 is seconded. While the reinforcing rubber layer 502 absorbs the tire, the rigidity of the entire tire during run-flat running can be ensured by the entire reinforcing rubber layer 50.
  • the tire width direction distance L1 between the tire width direction outer end 26A of the steel belt 26 and the tire width direction outer end 502B of the second reinforcing rubber layer 502 is 10 mm or more. is there.
  • the outer end 26A of the steel belt 26 in the tire width direction is arranged on the outer side of the second reinforcing rubber layer 502 in the tire radial direction with a margin, so that the outer end of the steel belt 26 in the tire width direction is arranged with a margin.
  • the second reinforcing rubber layer 502 reliably absorbs the stress concentration generated in 26A, and the durability during run-flat running can be further improved.
  • the tire width direction distance L2 between the ply split end 232A of the split second carcass ply 232 and the tire width direction inner end 502A of the second reinforcing rubber layer 502 is It is 10 mm or more.
  • the ply split end 232A of the second carcass ply 232 is arranged outside the tire radial direction of the second reinforcing rubber layer 502 with a margin, so that the stress concentration generated at the ply split end 232A
  • the second reinforcing rubber layer 502 reliably absorbs the tires, and the durability during run-flat running can be further improved.
  • the divided second carcass ply 232 and the steel belt 26 in the tire 1 according to the present embodiment are arranged so as to partially overlap each other, and the ply split end of the divided second carcass ply 232 is provided.
  • the tire width direction distance L3 between the 232A and the outer end 26A of the steel belt 26 in the tire width direction is 10 mm or more.
  • the tire of the present invention can be used as various tires for passenger cars, light trucks, trucks, buses, etc., and is particularly suitable as a tire for passenger cars.
  • the present invention is not limited to the above embodiment, and is included in the scope of the present invention even if it is modified or improved within the range in which the object of the present invention can be achieved.

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  • Engineering & Computer Science (AREA)
  • Mechanical Engineering (AREA)
  • Tires In General (AREA)

Abstract

Provided is a run-flat tire that can achieve weight reduction while ensuring steering stability. This run-flat tire comprises a reinforcement rubber layer 50 disposed on a tire inner cavity side of a carcass ply 23 on a side wall 12, wherein: the carcass ply 23 includes a plurality of layers of plies; at least one layer of ply of the plurality of layers of plies is a division carcass ply divided inside a steel belt in the tire radial direction; and the reinforcement rubber layer 50 is disposed inside a ply divided end of the divided ply in the tire radial direction.

Description

ランフラットタイヤRun flat tire
　本発明は、サイドウォールに補強ゴム層が配置されたサイド補強タイプのランフラットタイヤに関する。 The present invention relates to a side-reinforced type run-flat tire in which a reinforcing rubber layer is arranged on the sidewall.
　従来、サイドウォールに補強ゴム層を配置されたサイド補強タイプのランフラットタイヤが知られている。この補強ゴム層は、タイヤの内圧が低下した場合であっても、タイヤが完全に偏平化することを妨げる機能を有する。よって、ランフラットタイヤは、この補強ゴム層を備えることにより、ある程度の距離のランフラット走行（タイヤの内圧が低下した状態での走行）を行うことが可能である。
　例えば特許文献１には、重量の増加を抑制しつつ、ランフラット走行時のタイヤサイド部の剛性を向上させるために複数のカーカスプライの一端部側をベルト層の端部に重ねるカーカスの中抜き構造のランフラットタイヤが開示されている。
　また、特許文献２には、ランフラット走行時の耐久性および通常内圧走行時の乗り心地性を改良する上で、カーカスプライの少なくとも１枚がベルト層下で切り離された構造のランフラットタイヤが開示されている。 Conventionally, a side-reinforced type run-flat tire in which a reinforcing rubber layer is arranged on a sidewall is known. This reinforcing rubber layer has a function of preventing the tire from being completely flattened even when the internal pressure of the tire is reduced. Therefore, by providing the run-flat tire with this reinforcing rubber layer, it is possible to perform run-flat running (running in a state where the internal pressure of the tire is reduced) for a certain distance.
For example, in Patent Document 1, in order to improve the rigidity of the tire side portion during run-flat running while suppressing the increase in weight, one end side of a plurality of car cus plies is overlapped with the end portion of the belt layer. Structural run-flat tires are disclosed.
Further, Patent Document 2 describes a run-flat tire having a structure in which at least one carcass ply is separated under a belt layer in order to improve durability during run-flat running and riding comfort during normal internal pressure running. It is disclosed.
特開２０１４－２４３５８号公報Japanese Unexamined Patent Publication No. 2014-24358 特開２０００－３１８４０８号公報Japanese Unexamined Patent Publication No. 2000-318408
　特許文献１、２に示されるランフラットタイヤの場合、中抜きされたカーカスプライの端部周辺の剛性の変化が大きく、特にランフラット走行時において、この部分に応力が集中しやすく、歪みが生じやすい。よって、軽量化は図れるものの、良好な操縦安定性を得ることが難しい。 In the case of run-flat tires shown in Patent Documents 1 and 2, the change in rigidity around the end portion of the hollowed-out carcass ply is large, and stress tends to concentrate on this portion particularly during run-flat running, causing distortion. Cheap. Therefore, although weight reduction can be achieved, it is difficult to obtain good steering stability.
　本発明は、上記課題に鑑みてなされたものであり、その目的は、操縦安定性を確保しつつ、軽量化を図ることができるランフラットタイヤを提供することにある。 The present invention has been made in view of the above problems, and an object of the present invention is to provide a run-flat tire capable of reducing weight while ensuring steering stability.
　（１）本発明のランフラットタイヤ（例えば、タイヤ１）は、一対のビード（例えば、ビード１１）と、前記一対のビードの各々からタイヤ径方向外側に延びる一対のサイドウォール（例えば、サイドウォール１２）と、前記一対のサイドウォール間に配置されたトレッド（例えば、トレッド１３）と、前記一対のビード間に架け渡されたカーカスプライ（例えば、カーカスプライ２３）と、前記サイドウォールにおいて、前記カーカスプライのタイヤ内腔側に配置された補強ゴム層（例えば、補強ゴム層５０）と、を備え、前記トレッドにおいて、前記カーカスプライのタイヤ径方向外側にはベルト（例えば、スチールベルト２６）が配置され、前記カーカスプライは、複数層のプライ（例えば、第１カーカスプライ２３１、第２カーカスプライ２３２）により構成され、前記複数層のプライのうち、少なくとも１層のプライ（例えば、第２カーカスプライ２３２）が、前記ベルトのタイヤ径方向内側で分割された分割カーカスプライであり、前記分割されたプライのプライ分割端（例えば、プライ分割端２３２Ａ）のタイヤ径方向内側に、前記補強ゴム層が配置されている、ランフラットタイヤである。 (1) The run-flat tire (for example, tire 1) of the present invention has a pair of beads (for example, beads 11) and a pair of sidewalls (for example, sidewalls) extending outward in the tire radial direction from each of the pair of beads. 12), a tread (for example, a tread 13) arranged between the pair of sidewalls, a carcass ply (for example, a carcass ply 23) bridged between the pair of beads, and the sidewall. A reinforcing rubber layer (for example, a reinforcing rubber layer 50) arranged on the tire cavity side of the carcass ply is provided, and a belt (for example, a steel belt 26) is provided on the tire radial outer side of the carcass ply in the tread. The carcass ply is arranged, and the carcass ply is composed of a plurality of layers of plies (for example, a first carcass ply 231 and a second carcass ply 232), and at least one layer of the plies of the plurality of layers (for example, a second carcass) The ply 232) is a split carcass ply divided inside the tire radial direction of the belt, and the reinforcing rubber layer is formed inside the ply split end (for example, the ply split end 232A) of the split ply in the tire radial direction. It is a run-flat tire on which is placed.
　（２）（１）のランフラットタイヤにおいて、前記カーカスプライは、２層のプライ（例えば、第１カーカスプライ２３１、第２カーカスプライ２３２）により構成されており、前記２層のプライのうち、前記ベルト側のプライ（例えば、第２カーカスプライ２３２）のみが、前記ベルトのタイヤ径方向内側で分割されていてもよい。 (2) In the run-flat tire of (1), the carcass ply is composed of two layers of plies (for example, first carcass ply 231 and second carcass ply 232), and among the two layers of plies. Only the ply on the belt side (for example, the second carcass ply 232) may be divided inside the tire radial direction of the belt.
　（３）（１）または（２）のランフラットタイヤにおいて、前記補強ゴム層は、第１補強ゴム層（例えば、第１補強ゴム層５０１）と、第１補強ゴム層のタイヤ径方向外側に配置された第２補強ゴム層（例えば、第２補強ゴム層５０２）とにより構成されており、前記分割されたプライのプライ分割端のタイヤ径方向内側および、前記ベルトのタイヤ幅方向外側端（例えば、タイヤ幅方向外側端２６Ａ）のタイヤ径方向内側には、前記第２補強ゴム層が配置されており、前記第２補強ゴム層の硬度は、前記第１補強ゴム層の硬度よりも低くてもよい。 (3) In the run-flat tire according to (1) or (2), the reinforcing rubber layer is located on the outer side of the first reinforcing rubber layer (for example, the first reinforcing rubber layer 501) and the first reinforcing rubber layer in the tire radial direction. It is composed of a second reinforcing rubber layer (for example, a second reinforcing rubber layer 502) arranged, and the inner side of the ply split end of the split ply in the tire radial direction and the outer end in the tire width direction of the belt (for example, the outer end in the tire width direction of the belt). For example, the second reinforcing rubber layer is arranged inside the outer end 26A in the tire width direction in the tire radial direction, and the hardness of the second reinforcing rubber layer is lower than the hardness of the first reinforcing rubber layer. You may.
　（４）（３）のランフラットタイヤにおいて、前記ベルトのタイヤ幅方向外側端と、前記第２補強ゴム層のタイヤ幅方向外側端（例えば、タイヤ幅方向外側端５０２Ｂ）との、タイヤ幅方向距離Ｌ１は、１０ｍｍ以上であってもよい。 (4) In the run-flat tire of (3), the tire width direction of the outer end of the belt in the tire width direction and the outer end of the second reinforcing rubber layer in the tire width direction (for example, the outer end 502B in the tire width direction). The distance L1 may be 10 mm or more.
　（５）（３）または（４）のランフラットタイヤにおいて、前記分割されたプライのプライ分割端と、前記第２補強ゴム層のタイヤ幅方向内側端（例えば、タイヤ幅方向内側端５０２Ａ）との、タイヤ幅方向距離Ｌ２は、１０ｍｍ以上であってもよい。 (5) In the run-flat tire of (3) or (4), the ply split end of the split ply and the inner end of the second reinforcing rubber layer in the tire width direction (for example, the inner end 502A in the tire width direction) The tire width direction distance L2 may be 10 mm or more.
　（６）（３）～（５）のランフラットタイヤにおいて、前記分割されたプライと、前記ベルトは、一部が重なるように配置されており、前記分割されたプライのプライ分割端と、前記ベルトのタイヤ幅方向外側端との、タイヤ幅方向距離Ｌ３は、１０ｍｍ以上であってもよい。 (6) In the run-flat tires (3) to (5), the divided ply and the belt are arranged so as to partially overlap, and the ply divided end of the divided ply and the said belt. The distance L3 in the tire width direction from the outer end of the belt in the tire width direction may be 10 mm or more.
　本発明によれば、操縦安定性を確保しつつ、軽量化を図ることができるランフラットタイヤを提供することができる。 According to the present invention, it is possible to provide a run-flat tire capable of reducing weight while ensuring steering stability.
本発明の第１実施形態に係るランフラットタイヤのタイヤ幅方向の半断面を示す図である。It is a figure which shows the half cross section in the tire width direction of the run-flat tire which concerns on 1st Embodiment of this invention. 上記実施形態に係るランフラットタイヤの部分拡大断面図である。It is a partially enlarged sectional view of the run-flat tire which concerns on the said embodiment.
　以下、本発明の一実施形態について、図面を参照しながら説明する。
　図１は、本実施形態に係るランフラットタイヤであるタイヤ１のタイヤ幅方向の半断面を示す図である。タイヤ１の基本的な構造は、タイヤ幅方向の断面において左右対称となっているため、ここでは、右半分の断面図を示す。図中、符号Ｓ１は、タイヤ赤道面である。タイヤ赤道面Ｓ１は、タイヤ回転軸（タイヤ子午線）に直交する面で、かつタイヤ幅方向中心に位置する面である。
　ここで、タイヤ幅方向とは、タイヤ回転軸に平行な方向であり、図１の断面図における紙面左右方向である。図１においては、タイヤ幅方向Ｘとして図示されている。
　そして、タイヤ幅方向内側とは、タイヤ赤道面Ｓ１に近づく方向であり、図１においては、紙面左側である。タイヤ幅方向外側とは、タイヤ赤道面Ｓ１から離れる方向であり、図１においては、紙面右側である。
　また、タイヤ径方向とは、タイヤ回転軸に垂直な方向であり、図１における紙面上下方向である。図１においては、タイヤ径方向Ｙとして図示されている。
　そして、タイヤ径方向外側とは、タイヤ回転軸から離れる方向であり、図１においては、紙面上側である。タイヤ径方向内側とは、タイヤ回転軸に近づく方向であり、図１においては、紙面下側である。
　なお、図１の断面図は、タイヤを規定リムに装着して規定内圧を充填した無負荷状態のタイヤ幅方向断面図（タイヤ子午線断面図）である。なお、規定リムとは、タイヤサイズに対応してＪＡＴＭＡに定められた標準となるリムを指す。また、規定内圧とは、例えばタイヤが乗用車用である場合には１８０ｋＰａである。
　なお、後述する図２についても同様である。 Hereinafter, an embodiment of the present invention will be described with reference to the drawings.
FIG. 1 is a diagram showing a half cross section of a tire 1 which is a run-flat tire according to the present embodiment in the tire width direction. Since the basic structure of the tire 1 is symmetrical in the cross section in the tire width direction, the cross-sectional view of the right half is shown here. In the figure, reference numeral S1 is the tire equatorial plane. The tire equatorial plane S1 is a plane orthogonal to the tire rotation axis (tire meridian) and is located at the center in the tire width direction.
Here, the tire width direction is a direction parallel to the tire rotation axis, and is a paper surface left-right direction in the cross-sectional view of FIG. In FIG. 1, it is shown as the tire width direction X.
The inner side in the tire width direction is the direction approaching the tire equatorial plane S1, and is the left side of the paper surface in FIG. The outside in the tire width direction is the direction away from the tire equatorial plane S1, and is the right side of the paper surface in FIG.
The tire radial direction is a direction perpendicular to the tire rotation axis, and is a vertical direction on the paper surface in FIG. In FIG. 1, it is shown as the tire radial direction Y.
The outer side in the tire radial direction is a direction away from the tire rotation axis, and in FIG. 1, it is the upper side of the paper surface. The inside in the tire radial direction is a direction approaching the tire rotation axis, and in FIG. 1, it is the lower side of the paper surface.
The cross-sectional view of FIG. 1 is a cross-sectional view in the tire width direction (tire meridian cross-sectional view) in a no-load state in which a tire is mounted on a specified rim and filled with a specified internal pressure. The specified rim refers to a standard rim defined by JATTA according to the tire size. The specified internal pressure is, for example, 180 kPa when the tire is for a passenger car.
The same applies to FIG. 2, which will be described later.
　タイヤ１は、例えば乗用車用のランフラットタイヤであり、タイヤ幅方向両側に設けられた一対のビード１１と、ビード１１の各々からタイヤ径方向外側に延びるサイドウォール１２と、サイドウォール１２の各々のタイヤ径方向外側に連なって踏面（路面との接地面）１３Ｃを構成するトレッド１３と、を備える。 The tire 1 is, for example, a run-flat tire for a passenger car, and is a pair of beads 11 provided on both sides in the tire width direction, a sidewall 12 extending outward in the tire radial direction from each of the beads 11, and each of the sidewalls 12. The tread 13 is provided so as to form a tread surface (contact patch with the road surface) 13C which is connected to the outer side in the tire radial direction.
　ビード１１は、ビードコア２１と、ビードコア２１のタイヤ径方向外側に延出するビードフィラー２２とを備える。
　ビードコア２１は、ゴムが被覆された金属製のビードワイヤを複数回巻いて形成した環状の部材であり、空気が充填されたタイヤ１を、ホイールのリム（不図示）に固定する役目を果たす部材である。
　ビードフィラー２２は、ビードコア２１のタイヤ径方向外側に延出する、先端先細り形状のゴム部材である。ビードフィラー２２は、ビード周辺部の剛性を高め、高い操縦性および安定性を確保するために設けられている部材である。ビードフィラー２２は、例えば周囲のゴム部材よりも硬度の高いゴムにより構成される。 The bead 11 includes a bead core 21 and a bead filler 22 extending outward in the tire radial direction of the bead core 21.
The bead core 21 is an annular member formed by winding a metal bead wire coated with rubber a plurality of times, and is a member that serves to fix an air-filled tire 1 to a wheel rim (not shown). is there.
The bead filler 22 is a rubber member having a tapered tip that extends outward in the tire radial direction of the bead core 21. The bead filler 22 is a member provided for increasing the rigidity of the peripheral portion of the bead and ensuring high maneuverability and stability. The bead filler 22 is made of rubber having a hardness higher than that of the surrounding rubber member, for example.
　タイヤ１の内部には、一対のビード１１間を架け渡されたカーカスプライ２３が埋設されている。カーカスプライ２３は、タイヤ１の骨格となるプライを構成しており、一対のビード１１間を、一対のサイドウォール１２およびトレッド１３を通過する態様で、タイヤ１内に埋設されている。
　カーカスプライ２３は、一方のビードコア２１から他方のビードコア２１に延び、トレッド１３とビード１１との間を延在するプライ本体２４と、ビードコア２１の周りで折り返されているプライ折り返し部２５とを備える。本実施形態においては、プライ折り返し部２５は、プライ本体２４に重ね合わされている。
　カーカスプライ２３は、タイヤ幅方向に延びる複数のプライコードにより構成されている。また、複数のプライコードは、タイヤ周方向に並んで配列されている。このプライコードは、ポリエステルやポリアミド等の絶縁性の有機繊維コード等により構成されており、トッピングゴムにより被覆されている。
　そして、本実施形態のカーカスプライ２３は、第１カーカスプライ２３１および第２カーカスプライ２３２が重ねられた２層のカーカスプライによって構成されている。ただし、カーカスプライ２３は複数層であればよく、３層以上であってもよい。 Inside the tire 1, a carcass ply 23 bridged between a pair of beads 11 is embedded. The carcass ply 23 constitutes a ply that serves as a skeleton of the tire 1, and is embedded in the tire 1 so as to pass between the pair of beads 11 and the pair of sidewalls 12 and the tread 13.
The carcass ply 23 includes a ply body 24 extending from one bead core 21 to the other bead core 21 and extending between the tread 13 and the bead 11, and a ply folded portion 25 folded around the bead core 21. .. In the present embodiment, the ply folded portion 25 is overlapped with the ply main body 24.
The carcass ply 23 is composed of a plurality of ply cords extending in the tire width direction. Further, the plurality of ply cords are arranged side by side in the tire circumferential direction. This ply cord is made of an insulating organic fiber cord such as polyester or polyamide, and is coated with a topping rubber.
The carcass ply 23 of the present embodiment is composed of two layers of carcass plies in which the first carcass ply 231 and the second carcass ply 232 are stacked. However, the carcass ply 23 may have a plurality of layers and may have three or more layers.
　ビード１１は、チェーハー３１と、チェーハー３１のタイヤ幅方向外側に配置されたリムストリップゴム３２と、をさらに備える。
　チェーハー３１は、ビードコア２１周りに設けられたカーカスプライ２３のタイヤ径方向内側に設けられている。チェーハー３１は、カーカスプライ２３のプライ折り返し部２５のタイヤ幅方向外側にも延在している。
　リムストリップゴム３２は、チェーハー３１およびカーカスプライ２３のタイヤ幅方向外側に配置されており、リム装着時に、リム（不図示）と接触する部材である。 The bead 11 further includes a chaher 31 and a rim strip rubber 32 arranged on the outer side of the chaher 31 in the tire width direction.
The checker 31 is provided inside the carcass ply 23 provided around the bead core 21 in the tire radial direction. The chaher 31 also extends to the outside of the ply folded portion 25 of the carcass ply 23 in the tire width direction.
The rim strip rubber 32 is arranged on the outer side of the chaher 31 and the carcass ply 23 in the tire width direction, and is a member that comes into contact with the rim (not shown) when the rim is mounted.
　サイドウォール１２は、カーカスプライ２３のタイヤ幅方向内側に配置された補強ゴム層５０と、カーカスプライ２３の幅方向外側に配置されたサイドウォールゴム３０とを備える。
　補強ゴム層５０は、タイヤ幅方向断面視（タイヤ子午線断面視）において略三日月形状のサイド補強ゴムである。この補強ゴム層５０は、タイヤ１の内圧が低下した場合であっても、タイヤ１が完全に偏平化することを妨げる機能を有する。この補強ゴム層５０の詳細については後述する。
　サイドウォールゴム３０は、タイヤ１の外壁面を構成するゴム部材である。このサイドウォールゴム３０は、タイヤ１がクッション作用をする際に最もたわむ部分であり、通常、耐疲労性を有する柔軟なゴムが採用される。 The sidewall 12 includes a reinforcing rubber layer 50 arranged inside the carcass ply 23 in the tire width direction, and a sidewall rubber 30 arranged outside the carcass ply 23 in the width direction.
The reinforcing rubber layer 50 is a side reinforcing rubber having a substantially crescent shape in a cross-sectional view in the tire width direction (cross-sectional view of the tire meridian). The reinforcing rubber layer 50 has a function of preventing the tire 1 from being completely flattened even when the internal pressure of the tire 1 is reduced. Details of the reinforcing rubber layer 50 will be described later.
The sidewall rubber 30 is a rubber member that constitutes the outer wall surface of the tire 1. The sidewall rubber 30 is a portion that bends most when the tire 1 acts as a cushion, and a flexible rubber having fatigue resistance is usually adopted.
　トレッド１３は、カーカスプライ２３のタイヤ径方向外側に配置されたスチールベルト２６と、スチールベルト２６のタイヤ径方向外側に配置されたキャッププライ２７と、キャッププライ２７のタイヤ径方向外側に配置されたトレッドゴム２８と、を備える。
　スチールベルト２６は、ゴムで被覆された複数のスチールコードにより構成されている。スチールベルト２６を設けることにより、タイヤ１の剛性が確保され、トレッド１３と路面の接地状態が良くなる。本実施形態においては、２層構造のスチールベルト（内側のスチールベルト２６１と外側のスチールベルト２６２）が設けられているが、積層されるスチールベルト２６の枚数はこれに限らない。なお、スチールコードを用いたスチールベルト２６に替えて、アラミド繊維を用いたタイヤコード等を用いたベルトを用いてもよい。
　キャッププライ２７は、スチールベルト２６のタイヤ径方向外側に配置された部材であり、ベルト補強層としての機能を有する。キャッププライ２７は、ポリアミド繊維等の絶縁性の有機繊維層により構成されており、トッピングゴムにより被覆されている。キャッププライ２７を設けることにより、耐久性の向上、走行時のロードノイズの低減を図ることができる。本実施形態においては、キャッププライ２７のタイヤ幅方向外側端２７Ａは、スチールベルト２６のタイヤ幅方向外側端２６Ａよりもタイヤ幅方向外側に延出している。
　本実施形態の２層構造のスチールベルト２６は、内側のスチールベルト２６１が外側のスチールベルト２６２よりも幅広であり、したがってスチールベルト２６のタイヤ幅方向外側端２６Ａは、内側のスチールベルト２６１のタイヤ幅方向外側端で構成される。
　トレッドゴム２８は、通常走行時の踏面（路面との接地面）１３Ｃを構成する部材である。トレッドゴム２８の踏面１３Ｃには、複数の溝で構成されるトレッドパターン１３Ｄが設けられている。 The tread 13 is arranged on the tire radial outer side of the carcass ply 23, the cap ply 27 arranged on the tire radial outer side of the steel belt 26, and the tire radial outer side of the cap ply 27. It includes a tread rubber 28.
The steel belt 26 is composed of a plurality of steel cords coated with rubber. By providing the steel belt 26, the rigidity of the tire 1 is ensured, and the ground contact state between the tread 13 and the road surface is improved. In the present embodiment, a steel belt having a two-layer structure (inner steel belt 261 and outer steel belt 262) is provided, but the number of stacked steel belts 26 is not limited to this. Instead of the steel belt 26 using the steel cord, a belt using a tire cord or the like using aramid fiber may be used.
The cap ply 27 is a member arranged on the outer side of the steel belt 26 in the tire radial direction, and has a function as a belt reinforcing layer. The cap ply 27 is composed of an insulating organic fiber layer such as a polyamide fiber, and is covered with a topping rubber. By providing the cap ply 27, it is possible to improve the durability and reduce the road noise during traveling. In the present embodiment, the outer end 27A of the cap ply 27 in the tire width direction extends outward in the tire width direction from the outer end 26A of the steel belt 26 in the tire width direction.
In the two-layer structure steel belt 26 of the present embodiment, the inner steel belt 261 is wider than the outer steel belt 262, so that the outer end 26A of the steel belt 26 in the tire width direction is the tire of the inner steel belt 261. It consists of the outer edge in the width direction.
The tread rubber 28 is a member constituting the tread surface (contact patch with the road surface) 13C during normal traveling. The tread 13C of the tread rubber 28 is provided with a tread pattern 13D composed of a plurality of grooves.
　ビード１１、サイドウォール１２、トレッド１３において、カーカスプライ２３および補強ゴム層５０のタイヤ内腔側には、タイヤ１の内壁面を構成するゴム層としてのインナーライナー２９が設けられている。インナーライナー２９は、トレッド１３においては、主にカーカスプライ２３の内面を覆い、サイドウォール１２およびビード１１においては、主に補強ゴム層５０の内面を覆っている。インナーライナー２９は、耐空気透過性ゴムにより構成されており、タイヤ内腔内の空気が外部に漏れるのを防ぐ。 In the bead 11, the sidewall 12, and the tread 13, an inner liner 29 as a rubber layer constituting the inner wall surface of the tire 1 is provided on the tire lumen side of the carcass ply 23 and the reinforcing rubber layer 50. The inner liner 29 mainly covers the inner surface of the carcass ply 23 in the tread 13, and mainly covers the inner surface of the reinforcing rubber layer 50 in the sidewall 12 and the bead 11. The inner liner 29 is made of air-permeable rubber to prevent air in the tire lumen from leaking to the outside.
　ここで、図１に示されるように、サイドウォール１２のサイドウォールゴム３０は、トレッド１３に向かって延出している。一方、トレッド１３のトレッドゴム２８は、サイドウォール１２に向かって延出している。その結果、カーカスプライ２３の一部領域のタイヤ外表面側において、トレッドゴム２８と、サイドウォールゴム３０とが積層された状態となっている。より詳細には、サイドウォールゴム３０とトレッドゴム２８とが共に存在する領域、すなわちサイドウォール１２とトレッド１３の移行領域において、カーカスプライ２３のタイヤ外表面側に、サイドウォールゴム３０と、トレッドゴム２８とが、順に積層された状態となっている。 Here, as shown in FIG. 1, the sidewall rubber 30 of the sidewall 12 extends toward the tread 13. On the other hand, the tread rubber 28 of the tread 13 extends toward the sidewall 12. As a result, the tread rubber 28 and the sidewall rubber 30 are laminated on the outer surface side of the tire in a part of the carcass ply 23. More specifically, in the region where the sidewall rubber 30 and the tread rubber 28 coexist, that is, in the transition region between the sidewall 12 and the tread 13, the sidewall rubber 30 and the tread rubber are on the outer surface side of the tire of the carcass ply 23. 28 and 28 are stacked in this order.
　また、ビード１１とサイドウォール１２の移行領域付近においては、カーカスプライ２３のタイヤ外表面側に、リムストリップゴム３２とサイドウォールゴム３０とが、順に積層された状態となっている。また、この移行領域付近には、タイヤ幅方向外側に突出する頂部３３Ａを有してタイヤ周方向に環状に連続して延びるリムプロテクタ３３が設けられている。本実施形態においては、リムストリップゴム３２にリムプロテクタ３３の頂部３３Ａが設けられている。リムプロテクタ３３は、外傷からリム（不図示）を保護する機能を有する。 Further, in the vicinity of the transition region between the bead 11 and the sidewall 12, the rim strip rubber 32 and the sidewall rubber 30 are laminated in order on the tire outer surface side of the carcass ply 23. Further, in the vicinity of this transition region, a rim protector 33 having a top portion 33A protruding outward in the tire width direction and continuously extending in an annular shape in the tire circumferential direction is provided. In the present embodiment, the rim strip rubber 32 is provided with the top 33A of the rim protector 33. The rim protector 33 has a function of protecting the rim (not shown) from trauma.
　また、ビード１１においては、カーカスプライ２３のタイヤ内腔側に、補強ゴム層５０とチェーハー３１とが、順に積層された状態となっている。インナーライナー２９は、さらにこれらのゴム部材のタイヤ内腔側を覆っている。なお、カーカスプライ２３のタイヤ内腔側に、チェーハー３１と補強ゴム層５０とを、順に積層し、これらのゴム部材のタイヤ内腔側をインナーライナー２９で覆う構成としてもよい。 Further, in the bead 11, the reinforcing rubber layer 50 and the chaher 31 are laminated in this order on the tire lumen side of the carcass ply 23. The inner liner 29 further covers the tire lumen side of these rubber members. The chaher 31 and the reinforcing rubber layer 50 may be laminated in this order on the tire lumen side of the carcass ply 23, and the tire lumen side of these rubber members may be covered with the inner liner 29.
　このように、本実施形態のタイヤ１は、一対のビード１１と、一対のビード１１の各々からタイヤ径方向外側に延びる一対のサイドウォール１２と、一対のサイドウォール１２間に配置されたトレッド１３と、一対のビード１１間に架け渡されたカーカスプライ２３と、サイドウォール１２において、カーカスプライ２３のタイヤ内腔側に配置された補強ゴム層５０と、を備える。そして、トレッド１３において、カーカスプライ２３のタイヤ径方向外側にはベルトとしてのスチールベルト２６が配置されている。
　ここで、本実施形態のタイヤ１は、以下に詳述するように、カーカスプライ２３が、複数層のプライ（第１カーカスプライ２３１、第２カーカスプライ２３２）により構成され、複数層のプライのうち、少なくとも１層のプライ（第２カーカスプライ２３２）が、スチールベルト２６のタイヤ径方向内側で分割された分割カーカスプライとなっている。そして、分割されたプライのプライ分割端２３２Ａのタイヤ径方向内側に、補強ゴム層５０が配置されている。
　これにより、操縦安定性を確保しつつ、軽量化を図ることができる。 As described above, the tire 1 of the present embodiment has the pair of beads 11, the pair of sidewalls 12 extending outward in the tire radial direction from each of the pair of beads 11, and the tread 13 arranged between the pair of sidewalls 12. A carcass ply 23 bridged between the pair of beads 11 and a reinforcing rubber layer 50 arranged on the tire lumen side of the carcass ply 23 on the sidewall 12 are provided. Then, in the tread 13, a steel belt 26 as a belt is arranged on the outer side of the carcass ply 23 in the tire radial direction.
Here, in the tire 1 of the present embodiment, as described in detail below, the carcass ply 23 is composed of a plurality of layers of plies (first carcass ply 231 and second carcass ply 232), and the ply of the plurality of layers. Of these, at least one layer of ply (second carcass ply 232) is a split carcass ply that is divided inside the steel belt 26 in the tire radial direction. Then, the reinforcing rubber layer 50 is arranged inside the ply split end 232A of the split ply in the tire radial direction.
As a result, weight reduction can be achieved while ensuring steering stability.
　図２は、図１のタイヤ１における、サイドウォール１２とトレッド１３の境界領域周辺の拡大断面図である。 FIG. 2 is an enlarged cross-sectional view of the tire 1 of FIG. 1 around the boundary region between the sidewall 12 and the tread 13.
　本実施形態のカーカスプライ２３は、前述のとおり、第１カーカスプライ２３１および第２カーカスプライ２３２が重ねられた２層のカーカスプライによって構成されている。
　そして、２層のカーカスプライのうち、スチールベルト２６側の第２カーカスプライ２３２のみが、スチールベルト２６のタイヤ径方向内側で分割されている。第２カーカスプライ２３２のプライ分割端２３２Ａは、スチールベルト２６のタイヤ幅方向外側端２６Ａよりもタイヤ幅方向内側に位置している。そして、第２カーカスプライ２３２は分割されているため、第２カーカスプライ２３２のプライ分割端２３２Ａよりもタイヤ幅方向内側には第２カーカスプライ２３２は存在していない。 As described above, the carcass ply 23 of the present embodiment is composed of two layers of carcass plies in which the first carcass ply 231 and the second carcass ply 232 are stacked.
Of the two layers of carcass ply, only the second carcass ply 232 on the steel belt 26 side is divided inside the steel belt 26 in the tire radial direction. The ply split end 232A of the second carcass ply 232 is located inside the tire width direction outer end 26A of the steel belt 26 in the tire width direction. Since the second carcass ply 232 is divided, the second carcass ply 232 does not exist inside the ply divided end 232A of the second carcass ply 232 in the tire width direction.
　補強ゴム層５０は、第１補強ゴム層５０１と、第１補強ゴム層５０１のタイヤ径方向外側に配置された第２補強ゴム層５０２とにより構成されている。この第２補強ゴム層５０２は、第１補強ゴム層５０１よりも硬度が低い。
　そして、分割された第２カーカスプライ２３２のプライ分割端２３２Ａのタイヤ径方向内側および、スチールベルト２６のタイヤ幅方向外側端２６Ａのタイヤ径方向内側には、この第２補強ゴム層５０２が配置されている。
　なお、各部材は、タイヤ径方向内側からタイヤ径方向外側に向けて、第２補強ゴム層５０２、第１カーカスプライ２３１、第２カーカスプライ２３２、スチールベルト２６の順に積層された構成となっている。 The reinforcing rubber layer 50 is composed of a first reinforcing rubber layer 501 and a second reinforcing rubber layer 502 arranged on the outer side of the first reinforcing rubber layer 501 in the tire radial direction. The hardness of the second reinforcing rubber layer 502 is lower than that of the first reinforcing rubber layer 501.
The second reinforcing rubber layer 502 is arranged inside the tire radial direction of the ply split end 232A of the divided second carcass ply 232 and inside the tire radial direction of the tire width direction outer end 26A of the steel belt 26. ing.
Each member has a configuration in which the second reinforcing rubber layer 502, the first carcass ply 231 and the second carcass ply 232, and the steel belt 26 are laminated in this order from the inside in the tire radial direction to the outside in the tire radial direction. There is.
　ここで、図２に示すタイヤ幅方向断面視（タイヤ子午線断面視）において、スチールベルト２６のタイヤ幅方向外側端２６Ａと、第２補強ゴム層５０２のタイヤ幅方向外側端５０２Ｂとの、タイヤ幅方向距離Ｌ１は、１０ｍｍ以上であることが好ましい。
　この距離Ｌ１を１０ｍｍ以上とし、第２補強ゴム層５０２のタイヤ径方向外側に、スチールベルト２６のタイヤ幅方向外側端２６Ａが余裕を持って配置される態様とすることにより、スチールベルト２６のタイヤ幅方向外側端２６Ａで発生する応力集中を第２補強ゴム層５０２が確実に吸収し、ランフラット走行時の耐久性をより向上させることができる。 Here, in the tire width direction cross-sectional view (tire meridional cross-sectional view) shown in FIG. 2, the tire width of the tire width direction outer end 26A of the steel belt 26 and the tire width direction outer end 502B of the second reinforcing rubber layer 502. The direction distance L1 is preferably 10 mm or more.
By setting this distance L1 to 10 mm or more and arranging the outer end 26A of the steel belt 26 in the tire width direction on the outer side of the second reinforcing rubber layer 502 in the tire radial direction with a margin, the tire of the steel belt 26 The second reinforcing rubber layer 502 reliably absorbs the stress concentration generated at the outer end 26A in the width direction, and the durability during run-flat running can be further improved.
　また、分割された第２カーカスプライ２３２のプライ分割端２３２Ａと、第２補強ゴム層５０２のタイヤ幅方向内側端５０２Ａとの、タイヤ幅方向距離Ｌ２は、１０ｍｍ以上であることが好ましい。
　この距離Ｌ２を１０ｍｍ以上とし、第２補強ゴム層５０２のタイヤ径方向外側に、第２カーカスプライ２３２のプライ分割端２３２Ａが余裕を持って配置される態様とすることにより、プライ分割端２３２Ａで発生する応力集中を第２補強ゴム層５０２が確実に吸収し、ランフラット走行時の耐久性をより向上させることができる。 Further, the tire width direction distance L2 between the ply split end 232A of the divided second carcass ply 232 and the tire width direction inner end 502A of the second reinforcing rubber layer 502 is preferably 10 mm or more.
By setting the distance L2 to 10 mm or more and arranging the ply split end 232A of the second carcass ply 232 on the outer side of the second reinforcing rubber layer 502 in the tire radial direction with a margin, the ply split end 232A The second reinforcing rubber layer 502 reliably absorbs the generated stress concentration, and the durability during run-flat running can be further improved.
　そして、分割された第２カーカスプライ２３２と、スチールベルト２６は、一部が重なるように配置されており、分割された第２カーカスプライ２３２のプライ分割端２３２Ａと、スチールベルト２６のタイヤ幅方向外側端２６Ａとの、タイヤ幅方向距離Ｌ３は、１０ｍｍ以上であることが好ましい。
　この距離Ｌ３を１０ｍｍ以上とし、分割された第２カーカスプライ２３２と、スチールベルト２６が、確実に重なるような構成とすることにより、タイヤ１の製造工程において、タイヤの骨格となるカーカスプライ２３における、第１カーカスプライ２３１と第２カーカスプライが積層されている部分の上に、スチールベルト２６を載せる態様となるため、製造工程が安定し、作業性もよい。
　また、第１カーカスプライ２３１と、第２カーカスプライと、スチールベルト２６とが積層されている部分を有すことにより、ランフラット走行時の耐久性をより向上させることができる。 The divided second carcass ply 232 and the steel belt 26 are arranged so as to partially overlap each other, and the divided second carcass ply 232 ply split end 232A and the steel belt 26 in the tire width direction. The distance L3 in the tire width direction from the outer end 26A is preferably 10 mm or more.
By setting the distance L3 to 10 mm or more and configuring the divided second carcass ply 232 and the steel belt 26 so as to surely overlap each other, the carcass ply 23 which is the skeleton of the tire is formed in the manufacturing process of the tire 1. Since the steel belt 26 is placed on the portion where the first carcass ply 231 and the second carcass ply are laminated, the manufacturing process is stable and the workability is good.
Further, by having a portion in which the first carcass ply 231 and the second carcass ply and the steel belt 26 are laminated, the durability during run-flat running can be further improved.
　ここで、ビードフィラー２２および補強ゴム層５０に採用するゴムとしては、少なくともサイドウォールゴム３０およびインナーライナー２９よりも硬度が高いゴムを用いる。
　ゴムの硬度は、ＪＩＳ　Ｋ６２５３に準拠して、２３℃雰囲気において、タイプＡデュロメータで測定される値（デュロメータ硬さ）である。 Here, as the rubber used for the bead filler 22 and the reinforcing rubber layer 50, at least a rubber having a hardness higher than that of the sidewall rubber 30 and the inner liner 29 is used.
The hardness of rubber is a value (durometer hardness) measured by a type A durometer in an atmosphere of 23 ° C. in accordance with JIS K6253.
　例えば、サイドウォールゴム３０の硬度を基準としたとき、ビードフィラー２２および補強ゴム層５０の硬度は、サイドウォールゴム３０の硬度の１．１倍～２．３倍程度の硬度のゴムを用いる。
　より具体的には、サイドウォールゴム３０の硬度は、デュロメータ硬さで４５～６０の範囲内であるのに対して、補強ゴム層５０の硬度は、デュロメータ硬さで７０～１００の範囲内である。 For example, based on the hardness of the sidewall rubber 30, the hardness of the bead filler 22 and the reinforcing rubber layer 50 is about 1.1 to 2.3 times the hardness of the sidewall rubber 30.
More specifically, the hardness of the sidewall rubber 30 is in the range of 45 to 60 in the durometer hardness, whereas the hardness of the reinforcing rubber layer 50 is in the range of 70 to 100 in the durometer hardness. is there.
　そして、補強ゴム層５０を構成する第２補強ゴム層５０２の硬度は、第１補強ゴム層５０１の硬度よりも低く設定されている。具体的には、第１補強ゴム層５０１の硬度は、デュロメータ硬さで７５～１００であることが好ましく、第２補強ゴム層５０２の硬度は、第１補強ゴム層５０１の硬度よりも低く、かつデュロメータ硬さで７０～８５であることが好ましい。 The hardness of the second reinforcing rubber layer 502 constituting the reinforcing rubber layer 50 is set lower than the hardness of the first reinforcing rubber layer 501. Specifically, the hardness of the first reinforcing rubber layer 501 is preferably 75 to 100 in terms of durometer hardness, and the hardness of the second reinforcing rubber layer 502 is lower than the hardness of the first reinforcing rubber layer 501. Moreover, the hardness of the durometer is preferably 70 to 85.
　このように、分割された第２カーカスプライ２３２のプライ分割端２３２Ａのタイヤ径方向内側に、補強ゴム層５０が配置されている態様において、第２補強ゴム層５０２の硬度を第１補強ゴム層５０１の硬度よりも低くすることで、プライ分割端２３２Ａで発生する応力集中を第２補強ゴム層５０２が効果的に吸収しつつ、ランフラット走行時のタイヤ全体の剛性を補強ゴム層５０全体により確保することができる。
　また、スチールベルト２６のタイヤ幅方向外側端２６Ａのタイヤ径方向内側に補強ゴム層５０が配置されている態様において、第２補強ゴム層５０２の硬度を第１補強ゴム層５０１の硬度よりも低くすることで、スチールベルト２６のタイヤ幅方向外側端２６Ａで発生する応力集中を第２補強ゴム層５０２が効果的に吸収しつつ、ランフラット走行時のタイヤ全体の剛性を補強ゴム層５０全体によって確保することができる。 In the embodiment in which the reinforcing rubber layer 50 is arranged inside the ply divided end 232A of the divided second carcass ply 232 in the tire radial direction, the hardness of the second reinforcing rubber layer 502 is set to the hardness of the first reinforcing rubber layer. By making the hardness lower than 501, the second reinforcing rubber layer 502 effectively absorbs the stress concentration generated at the ply split end 232A, and the rigidity of the entire tire during run-flat running is increased by the entire reinforcing rubber layer 50. Can be secured.
Further, in the embodiment in which the reinforcing rubber layer 50 is arranged inside the outer end 26A of the steel belt 26 in the tire width direction in the tire radial direction, the hardness of the second reinforcing rubber layer 502 is lower than the hardness of the first reinforcing rubber layer 501. By doing so, the second reinforcing rubber layer 502 effectively absorbs the stress concentration generated at the outer end 26A of the steel belt 26 in the tire width direction, and the rigidity of the entire tire during run flat running is increased by the entire reinforcing rubber layer 50. Can be secured.
　なお、本実施形態に示されるように、カーカスプライ２３は、２層のカーカスプライによって構成されており、２層のカーカスプライのうち、スチールベルト２６側の第２カーカスプライ２３２のみが、スチールベルト２６のタイヤ径方向内側で分割されている構成が、操縦安定性の確保と軽量化のバランスの面から考えて特に好ましいが、カーカスプライ２３の構成はこれに限らない。例えば、２層のカーカスプライとも、スチールベルト２６のタイヤ径方向内側で分割されている構成であってもよい。また、第１カーカスプライ２３１のみが、スチールベルト２６のタイヤ径方向内側で分割されている構成であってもよい。また、カーカスプライ２３が、３層以上のプライにより構成され、３層以上のプライのうち、少なくとも１層のプライが、スチールベルト２６のタイヤ径方向内側で分割された分割カーカスプライとなっている構成であってもよい。これらの場合においても、分割されたプライのプライ分割端のタイヤ径方向内側に、補強ゴム層５０が配置されることで、操縦安定性を確保しつつ、軽量化を図ることができる。 As shown in the present embodiment, the carcass ply 23 is composed of two layers of carcass ply, and of the two layers of carcass ply, only the second carcass ply 232 on the steel belt 26 side is a steel belt. The configuration divided inside the tire radial direction of 26 is particularly preferable from the viewpoint of ensuring steering stability and weight reduction, but the configuration of the carcass ply 23 is not limited to this. For example, both the two-layer carcass ply may be divided inside the steel belt 26 in the tire radial direction. Further, only the first carcass ply 231 may be divided inside the steel belt 26 in the tire radial direction. Further, the carcass ply 23 is composed of three or more layers of plies, and at least one of the three or more layers of plies is a divided carcass ply divided inside the tire radial direction of the steel belt 26. It may be a configuration. Even in these cases, by arranging the reinforcing rubber layer 50 inside the split end of the split ply in the tire radial direction, it is possible to reduce the weight while ensuring steering stability.
　なお、本実施形態に示されるように、補強ゴム層５０は、第１補強ゴム層５０１と、第２補強ゴム層５０２とにより構成されていることが好ましいが、補強ゴム層５０が、ひとつのゴム部材により構成されていてもよい。この場合においても、分割されたプライのプライ分割端のタイヤ径方向内側に、補強ゴム層５０が配置されることで、操縦安定性を確保しつつ、軽量化を図ることができる。 As shown in the present embodiment, the reinforcing rubber layer 50 is preferably composed of the first reinforcing rubber layer 501 and the second reinforcing rubber layer 502, but the reinforcing rubber layer 50 is one. It may be composed of a rubber member. Even in this case, by arranging the reinforcing rubber layer 50 inside the split end of the split ply in the tire radial direction, it is possible to reduce the weight while ensuring steering stability.
　本実施形態のタイヤ１によれば、以下の効果を奏する。 According to the tire 1 of the present embodiment, the following effects are obtained.
　（１）本実施形態に係るタイヤ１は、一対のビード１１と、一対のビード１１の各々からタイヤ径方向外側に延びる一対のサイドウォール１２と、一対のサイドウォール１２間に配置されたトレッド１３と、一対のビード１１間に架け渡されたカーカスプライ２３と、サイドウォール１２において、カーカスプライ２３のタイヤ内腔側に配置された補強ゴム層５０と、を備えるランフラットタイヤであって、トレッド１３において、カーカスプライ２３のタイヤ径方向外側にはスチールベルト２６が配置され、カーカスプライ２３は、複数層のプライ（第１カーカスプライ２３１、第２カーカスプライ２３２）により構成され、複数層のプライのうち、少なくとも１層のプライが、スチールベルト２６のタイヤ径方向内側で分割された分割カーカスプライであり、分割されたプライのプライ分割端のタイヤ径方向内側に、補強ゴム層５０が配置されている。
　このように、分割プライを採用し、かつ補強ゴム層を適切な位置に配置することにより、操縦安定性を確保しつつ、軽量化を図ることができる。 (1) The tire 1 according to the present embodiment includes a pair of beads 11, a pair of sidewalls 12 extending outward in the tire radial direction from each of the pair of beads 11, and a tread 13 arranged between the pair of sidewalls 12. A run-flat tire comprising a carcass ply 23 bridged between a pair of beads 11 and a reinforcing rubber layer 50 arranged on the tire cavity side of the carcass ply 23 on the sidewall 12. In 13, a steel belt 26 is arranged outside the tire radial direction of the carcass ply 23, and the carcass ply 23 is composed of a plurality of layers of plies (first carcass ply 231 and second carcass ply 232), and the carcass ply 23 is composed of a plurality of layers of plies. Of these, at least one ply is a split carcass ply divided inside the tire radial direction of the steel belt 26, and the reinforcing rubber layer 50 is arranged inside the tire radial direction at the ply split end of the divided ply. ing.
In this way, by adopting the split ply and arranging the reinforcing rubber layer at an appropriate position, it is possible to reduce the weight while ensuring the steering stability.
　（２）本実施形態に係るタイヤ１のカーカスプライ２３は、２層のプライ（第１カーカスプライ２３１、第２カーカスプライ２３２）により構成されており、２層のプライのうち、スチールベルト２６側の第２カーカスプライ２３２のみが、スチールベルト２６のタイヤ径方向内側で分割されている。
　このように、２層のプライのうち、スチールベルト２６側の第２カーカスプライ２３２のみを分割プライとし、かつ補強ゴム層を適切な位置に配置することにより、操縦安定性を確保しつつ、軽量化をより適切に図ることができる。 (2) The carcass ply 23 of the tire 1 according to the present embodiment is composed of two layers of plies (first carcass ply 231 and second carcass ply 232), and of the two layers of plies, the steel belt 26 side. Only the second carcass ply 232 of the above is divided inside the tire radial direction of the steel belt 26.
In this way, of the two layers of ply, only the second carcass ply 232 on the steel belt 26 side is used as the split ply, and the reinforcing rubber layer is arranged at an appropriate position, thereby ensuring steering stability and being lightweight. It can be made more appropriate.
　（３）本実施形態に係るタイヤ１は、補強ゴム層５０が、第１補強ゴム層５０１と、第１補強ゴム層５０１のタイヤ径方向外側に配置された第２補強ゴム層５０２とにより構成されており、分割された第２カーカスプライ２３２のプライ分割端２３２Ａのタイヤ径方向内側および、スチールベルト２６のタイヤ幅方向外側端２６Ａのタイヤ径方向内側には、第２補強ゴム層５０２が配置されており、第２補強ゴム層５０２の硬度は、第１補強ゴム層５０１の硬度よりも低い。
　このように、第２補強ゴム層５０２の硬度を第１補強ゴム層の硬度よりも低くすることで、プライ分割端２３２Ａやスチールベルト２６のタイヤ幅方向外側端２６Ａで発生する応力集中を第２補強ゴム層５０２が吸収しつつ、ランフラット走行時のタイヤ全体の剛性を補強ゴム層５０全体によって確保することができる。 (3) In the tire 1 according to the present embodiment, the reinforcing rubber layer 50 is composed of a first reinforcing rubber layer 501 and a second reinforcing rubber layer 502 arranged on the outer side of the first reinforcing rubber layer 501 in the tire radial direction. The second reinforcing rubber layer 502 is arranged inside the tire radial direction of the ply split end 232A of the divided second carcass ply 232 and inside the tire radial direction of the tire width direction outer end 26A of the steel belt 26. The hardness of the second reinforcing rubber layer 502 is lower than the hardness of the first reinforcing rubber layer 501.
By making the hardness of the second reinforcing rubber layer 502 lower than the hardness of the first reinforcing rubber layer in this way, the stress concentration generated at the ply split end 232A and the outer end 26A in the tire width direction of the steel belt 26 is seconded. While the reinforcing rubber layer 502 absorbs the tire, the rigidity of the entire tire during run-flat running can be ensured by the entire reinforcing rubber layer 50.
　（４）本実施形態に係るタイヤ１における、スチールベルト２６のタイヤ幅方向外側端２６Ａと、第２補強ゴム層５０２のタイヤ幅方向外側端５０２Ｂとの、タイヤ幅方向距離Ｌ１は、１０ｍｍ以上である。
　このように、第２補強ゴム層５０２のタイヤ径方向外側に、スチールベルト２６のタイヤ幅方向外側端２６Ａが余裕を持って配置される態様とすることにより、スチールベルト２６のタイヤ幅方向外側端２６Ａで発生する応力集中を第２補強ゴム層５０２が確実に吸収し、ランフラット走行時の耐久性をより向上させることができる。 (4) In the tire 1 according to the present embodiment, the tire width direction distance L1 between the tire width direction outer end 26A of the steel belt 26 and the tire width direction outer end 502B of the second reinforcing rubber layer 502 is 10 mm or more. is there.
In this way, the outer end 26A of the steel belt 26 in the tire width direction is arranged on the outer side of the second reinforcing rubber layer 502 in the tire radial direction with a margin, so that the outer end of the steel belt 26 in the tire width direction is arranged with a margin. The second reinforcing rubber layer 502 reliably absorbs the stress concentration generated in 26A, and the durability during run-flat running can be further improved.
　（５）本実施形態に係るタイヤ１における、分割された第２カーカスプライ２３２のプライ分割端２３２Ａと、第２補強ゴム層５０２のタイヤ幅方向内側端５０２Ａとの、タイヤ幅方向距離Ｌ２は、１０ｍｍ以上である。
　このように、第２補強ゴム層５０２のタイヤ径方向外側に、第２カーカスプライ２３２のプライ分割端２３２Ａが余裕を持って配置される態様とすることにより、プライ分割端２３２Ａで発生する応力集中を第２補強ゴム層５０２が確実に吸収し、ランフラット走行時の耐久性をより向上させることができる。 (5) In the tire 1 according to the present embodiment, the tire width direction distance L2 between the ply split end 232A of the split second carcass ply 232 and the tire width direction inner end 502A of the second reinforcing rubber layer 502 is It is 10 mm or more.
In this way, the ply split end 232A of the second carcass ply 232 is arranged outside the tire radial direction of the second reinforcing rubber layer 502 with a margin, so that the stress concentration generated at the ply split end 232A The second reinforcing rubber layer 502 reliably absorbs the tires, and the durability during run-flat running can be further improved.
　（６）本実施形態に係るタイヤ１における、分割された第２カーカスプライ２３２と、スチールベルト２６は、一部が重なるように配置されており、分割された第２カーカスプライ２３２のプライ分割端２３２Ａと、スチールベルト２６のタイヤ幅方向外側端２６Ａとの、タイヤ幅方向距離Ｌ３は、１０ｍｍ以上である。
　このように、分割された第２カーカスプライ２３２と、スチールベルト２６が、確実に重なるような構成とすることにより、タイヤ１の製造工程において、タイヤの骨格となるカーカスプライ２３における、第１カーカスプライ２３１と第２カーカスプライが積層されている部分の上に、スチールベルト２６を載せることができるため、製造工程が安定し、作業性もよい。 (6) The divided second carcass ply 232 and the steel belt 26 in the tire 1 according to the present embodiment are arranged so as to partially overlap each other, and the ply split end of the divided second carcass ply 232 is provided. The tire width direction distance L3 between the 232A and the outer end 26A of the steel belt 26 in the tire width direction is 10 mm or more.
By configuring the divided second carcass ply 232 and the steel belt 26 to surely overlap each other in this way, in the manufacturing process of the tire 1, the first carcass in the carcass ply 23 which is the skeleton of the tire Since the steel belt 26 can be placed on the portion where the ply 231 and the second carcass ply are laminated, the manufacturing process is stable and the workability is good.
　なお、本発明のタイヤは、乗用車、ライトトラック、トラック、バス等の各種タイヤとして採用することができるが、特に乗用車用のタイヤとして好適である。
　なお、本発明は上記実施形態に限定されず、本発明の目的を達成できる範囲で変形、改良などを行っても、本発明の範囲に含まれる。 The tire of the present invention can be used as various tires for passenger cars, light trucks, trucks, buses, etc., and is particularly suitable as a tire for passenger cars.
The present invention is not limited to the above embodiment, and is included in the scope of the present invention even if it is modified or improved within the range in which the object of the present invention can be achieved.
　１　タイヤ
　１１　ビード
　１２　サイドウォール
　１３　トレッド
　２１　ビードコア
　２２　ビードフィラー
　２３　カーカスプライ
　２３１　第１カーカスプライ
　２３２　第２カーカスプライ
　２３２Ａ　プライ分割端
　２４　プライ本体
　２５　プライ折り返し部
　２６　スチールベルト（ベルト）
　２６Ａ　タイヤ幅方向外側端
　２７　キャッププライ
　２８　トレッドゴム
　２９　インナーライナー
　３０　サイドウォールゴム
　３１　チェーハー
　３２　リムストリップゴム
　３３　リムプロテクタ
　３３Ａ　頂部
　５０　補強ゴム層
　５０１　第１補強ゴム層
　５０２　第２補強ゴム層
　５０２Ａ　タイヤ径方向外側端
　５０２Ｂ　タイヤ径方向内側端 1 Tire 11 Bead 12 Sidewall 13 Tread 21 Bead Core 22 Bead Filler 23 Carcass Ply 231 1st Carcass Ply 232 2nd Carcass Ply 232A Ply Split End 24 Ply Body 25 Ply Folded Part 26 Steel Belt (Belt)
26A Tire width direction outer end 27 Cap ply 28 Tread rubber 29 Inner liner 30 Side wall rubber 31 Chaher 32 Rim strip rubber 33 Rim protector 33A Top 50 Reinforcing rubber layer 501 1st reinforcing rubber layer 502 2nd reinforcing rubber layer 502A Tire radial direction Outer end 502B Tire radial inner end

Claims (6)

  1. 　一対のビードと、
    　前記一対のビードの各々からタイヤ径方向外側に延びる一対のサイドウォールと、
    　前記一対のサイドウォール間に配置されたトレッドと、
    　前記一対のビード間に架け渡されたカーカスプライと、
    　前記サイドウォールにおいて、前記カーカスプライのタイヤ内腔側に配置された補強ゴム層と、を備えるランフラットタイヤであって、
    　前記トレッドにおいて、前記カーカスプライのタイヤ径方向外側にはベルトが配置され、
    　前記カーカスプライは、複数層のプライにより構成され、前記複数層のプライのうち、少なくとも１層のプライが、前記ベルトのタイヤ径方向内側で分割された分割カーカスプライであり、
    　前記分割されたプライのプライ分割端のタイヤ径方向内側に、前記補強ゴム層が配置されている、ランフラットタイヤ。     A pair of beads and
    A pair of sidewalls extending outward in the tire radial direction from each of the pair of beads,
    The tread placed between the pair of sidewalls and
    A carcass ply bridged between the pair of beads
    A run-flat tire comprising a reinforcing rubber layer arranged on the tire lumen side of the carcass ply on the sidewall.
    In the tread, a belt is arranged on the outer side of the carcass ply in the tire radial direction.
    The carcass ply is composed of a plurality of layers of plies, and at least one layer of the plies of the plurality of layers is a divided carcass ply divided inside the tire radial direction of the belt.
    A run-flat tire in which the reinforcing rubber layer is arranged inside the split end of the split ply in the tire radial direction.
  2. 　前記カーカスプライは、２層のプライにより構成されており、
    　前記２層のプライのうち、前記ベルト側のプライのみが、前記ベルトのタイヤ径方向内側で分割されている、請求項１に記載のランフラットタイヤ。     The carcass ply is composed of two layers of plies.
    The run-flat tire according to claim 1, wherein only the ply on the belt side of the two layers of plies is divided inside the tire radial direction of the belt.
  3. 　前記補強ゴム層は、第１補強ゴム層と、第１補強ゴム層のタイヤ径方向外側に配置された第２補強ゴム層とにより構成されており、
    　前記分割されたプライのプライ分割端のタイヤ径方向内側および、前記ベルトのタイヤ幅方向外側端のタイヤ径方向内側には、前記第２補強ゴム層が配置されており、
    　前記第２補強ゴム層の硬度は、前記第１補強ゴム層の硬度よりも低い、請求項１または請求項２に記載のランフラットタイヤ。     The reinforcing rubber layer is composed of a first reinforcing rubber layer and a second reinforcing rubber layer arranged on the outer side of the first reinforcing rubber layer in the tire radial direction.
    The second reinforcing rubber layer is arranged inside the tire radial direction at the ply split end of the divided ply and inside the tire radial direction at the tire width direction outer end of the belt.
    The run-flat tire according to claim 1 or 2, wherein the hardness of the second reinforcing rubber layer is lower than the hardness of the first reinforcing rubber layer.
  4. 　前記ベルトのタイヤ幅方向外側端と、前記第２補強ゴム層のタイヤ幅方向外側端との、タイヤ幅方向距離は、１０ｍｍ以上である、請求項３に記載のランフラットタイヤ。 The run-flat tire according to claim 3, wherein the distance in the tire width direction between the outer end in the tire width direction of the belt and the outer end in the tire width direction of the second reinforcing rubber layer is 10 mm or more.
  5. 　前記分割されたプライのプライ分割端と、前記第２補強ゴム層のタイヤ幅方向内側端との、タイヤ幅方向距離は、１０ｍｍ以上である、請求項３または請求項４に記載のランフラットタイヤ。 The run-flat tire according to claim 3 or 4, wherein the distance in the tire width direction between the ply split end of the divided ply and the inner end in the tire width direction of the second reinforcing rubber layer is 10 mm or more. ..
  6. 　前記分割されたプライと、前記ベルトは、一部が重なるように配置されており、
    　前記分割されたプライのプライ分割端と、前記ベルトのタイヤ幅方向外側端との、タイヤ幅方向距離は、１０ｍｍ以上である、請求項３～５のいずれか１項に記載のランフラットタイヤ。     The divided ply and the belt are arranged so as to partially overlap each other.
    The run-flat tire according to any one of claims 3 to 5, wherein the distance in the tire width direction between the ply split end of the divided ply and the outer end in the tire width direction of the belt is 10 mm or more.
PCT/JP2020/042725 2019-12-11 2020-11-17 Run-flat tire WO2021117425A1 (en)

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Citations (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JPS62279107A (en) * 1986-05-28 1987-12-04 Bridgestone Corp Pneumatic safety tire
JP2005306371A (en) * 2004-04-22 2005-11-04 Goodyear Tire & Rubber Co:The Run-flat tire
JP2010137853A (en) * 2008-12-12 2010-06-24 Goodyear Tire & Rubber Co:The Self-supporting type pneumatic tire having optimized ply line
JP2014024358A (en) * 2012-07-24 2014-02-06 Bridgestone Corp Run-flat tire
US20160121664A1 (en) * 2014-10-29 2016-05-05 Bridgestone Corporation Run-flat tire

Patent Citations (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JPS62279107A (en) * 1986-05-28 1987-12-04 Bridgestone Corp Pneumatic safety tire
JP2005306371A (en) * 2004-04-22 2005-11-04 Goodyear Tire & Rubber Co:The Run-flat tire
JP2010137853A (en) * 2008-12-12 2010-06-24 Goodyear Tire & Rubber Co:The Self-supporting type pneumatic tire having optimized ply line
JP2014024358A (en) * 2012-07-24 2014-02-06 Bridgestone Corp Run-flat tire
US20160121664A1 (en) * 2014-10-29 2016-05-05 Bridgestone Corporation Run-flat tire

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