WO2019239895A1 - Pneumatic tire - Google Patents

Pneumatic tire Download PDF

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Publication number
WO2019239895A1
WO2019239895A1 PCT/JP2019/021328 JP2019021328W WO2019239895A1 WO 2019239895 A1 WO2019239895 A1 WO 2019239895A1 JP 2019021328 W JP2019021328 W JP 2019021328W WO 2019239895 A1 WO2019239895 A1 WO 2019239895A1
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WO
WIPO (PCT)
Prior art keywords
belt
layer
tire
resin
pneumatic tire
Prior art date
Application number
PCT/JP2019/021328
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French (fr)
Japanese (ja)
Inventor
福島　敦
正之 有馬
Original Assignee
株式会社ブリヂストン
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Application filed by 株式会社ブリヂストン filed Critical 株式会社ブリヂストン
Publication of WO2019239895A1 publication Critical patent/WO2019239895A1/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
    • B60C9/00—Reinforcements or ply arrangement of pneumatic tyres
    • B60C9/18—Structure or arrangement of belts or breakers, crown-reinforcing or cushioning layers
    • B60C9/20—Structure or arrangement of belts or breakers, crown-reinforcing or cushioning layers built-up from rubberised plies each having all cords arranged substantially parallel
    • 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
    • B60C9/18—Structure or arrangement of belts or breakers, crown-reinforcing or cushioning layers
    • B60C9/20—Structure or arrangement of belts or breakers, crown-reinforcing or cushioning layers built-up from rubberised plies each having all cords arranged substantially parallel
    • B60C9/22—Structure or arrangement of belts or breakers, crown-reinforcing or cushioning layers built-up from rubberised plies each having all cords arranged substantially parallel the plies being arranged with all cords disposed along the circumference of the tyre

Definitions

  • the present disclosure relates to a pneumatic tire having a belt provided with a resin layer.
  • pneumatic tires to be mounted on automobiles there are pneumatic tires including a belt configured to include a resin layer on the outer side in the tire radial direction of the carcass (for example, JP 2007-069745 A, JP 2002-002220 A). (Publication)
  • a reinforcing layer called a layer is provided so as to cover the end of the belt, but the resin layer of the belt covered with the layer may crack due to the effect of the layer.
  • the present disclosure is intended to provide a pneumatic tire that can suppress the occurrence of cracks in the resin layer of the belt in consideration of the above facts.
  • a pneumatic tire according to the present disclosure includes a carcass straddling one bead portion to the other bead portion, a belt that is disposed on the outer side in the tire radial direction of the carcass and includes at least a resin layer, and at least the tire of the belt A layer covering an end portion in the width direction; and a buffer layer disposed between the carcass and the layer.
  • the buffer layer is provided between the layer and the belt, the force from the layer can be buffered by the buffer layer, and the occurrence of cracks in the resin layer of the belt is suppressed. I can do it.
  • the carcass ply 14 is formed by coating a plurality of cords (not shown) extending in the radial direction of the pneumatic tire 10 with a coating rubber (not shown). That is, the pneumatic tire 10 of the present embodiment is a so-called radial pneumatic tire.
  • the material of the cord of the carcass ply 14 is, for example, PET, but may be another conventionally known material.
  • the end portion of the carcass ply 14 in the tire width direction is folded back from the bead core 12 in the tire radial direction.
  • a portion extending from one bead core 12 to the other bead core 12 is called a main body portion 14 ⁇ / b> A
  • a portion folded from the bead core 12 is called a folded portion 14 ⁇ / b> B.
  • the cross-sectional shape of the main body portion 14A of the carcass ply 14 in the pneumatic tire 10 of the present embodiment is the same cross-sectional shape as that of a conventional general pneumatic tire, and the vicinity of the tire equatorial plane CL has a substantially constant radius and a flat shape. Yes, the radius gradually decreases near the shoulder.
  • a bead filler 18 whose thickness gradually decreases from the bead core 12 toward the outer side in the tire radial direction is disposed.
  • a bead portion 20 is a portion on the inner side in the tire radial direction from the tire radial direction outer end 18A of the bead filler 18.
  • An inner liner 22 made of rubber is disposed inside the pneumatic tire of the carcass 16.
  • a side rubber layer 24A is disposed on the outer side in the tire radial direction
  • a side rubber layer 24B is disposed on the inner side in the tire radial direction. Note that a part of the side rubber layer 24 ⁇ / b> B is folded back on the radially inner side of the bead core 12 and extends to a part of the tire inner surface.
  • a tire case 25 is configured by the bead core 12, the carcass 16, the bead filler 18, the inner liner 22, the side rubber layer 24A, and the side rubber layer 24B.
  • the tire case 25 is a pneumatic tire frame member that forms the frame of the pneumatic tire 10.
  • a belt 26 is provided on the outer side of the crown portion of the carcass 16, in other words, on the outer side in the tire radial direction of the carcass 16 to restrain the outer peripheral portion of the carcass 16 to obtain a tag effect.
  • the belt 26 of the present embodiment is formed substantially flat when viewed in a cross section along the rotation axis. In other words, the central portion in the tire width direction is formed in a straight line parallel to the tire rotation axis. However, both end portions in the tire width direction are slightly curved inward in the tire radial direction. It should be noted that the degree of curvature of both ends of the belt 26 in the tire width direction is smaller than the degree of curvature of the carcass 16. Therefore, most of the belt 26 is in close contact with the outer peripheral surface of the carcass 16 at the center in the tire width direction, but a part of both sides in the width direction is separated from the outer peripheral surface of the carcass 16.
  • the belt 26 of the present embodiment is formed by winding a plurality (two in the present embodiment) of reinforcing cords 30 around a resin-coated cord 34 covered with a resin 32. A method for manufacturing the belt 26 will be described later.
  • the reinforcing cord 30 of the belt 26 is preferably thicker than the cord of the carcass ply 14 and has a high strength (tensile strength).
  • the reinforcing cord 30 of the belt 26 can be composed of monofilament (single wire) such as metal fiber or organic fiber, or multifilament (twisted wire) obtained by twisting these fibers.
  • the reinforcing cord 30 of the present embodiment is a steel cord.
  • the resin 32 that covers the reinforcing cord 30 is made of a rubber material that constitutes the side rubber layers 24A and 24B and a resin material that has a higher tensile elastic modulus than a rubber material that constitutes the tread portion 36 described later.
  • an elastic thermoplastic resin, a thermoplastic elastomer (TPE), a thermosetting resin, or the like can be used as the resin 32 covering the reinforcing cord 30.
  • TPE thermoplastic elastomer
  • thermosetting resin or the like.
  • thermoplastic elastomers polyolefin-based thermoplastic elastomer (TPO), polystyrene-based thermoplastic elastomer (TPS), polyamide-based thermoplastic elastomer (TPA), polyurethane-based thermoplastic elastomer (TPU), polyester-based thermoplastic elastomer (TPC) And dynamic crosslinkable thermoplastic elastomer (TPV).
  • TPO polyolefin-based thermoplastic elastomer
  • TPS polystyrene-based thermoplastic elastomer
  • TPA polyamide-based thermoplastic elastomer
  • TPU polyurethane-based thermoplastic elastomer
  • TPC polyester-based thermoplastic elastomer
  • TPV dynamic crosslinkable thermoplastic elastomer
  • thermoplastic resin examples include polyurethane resin, polyolefin resin, vinyl chloride resin, polyamide resin and the like.
  • the deflection temperature under load (when 0.45 MPa is loaded) specified in ISO 75-2 or ASTM D648 is 78 ° C or higher
  • the tensile yield strength specified in JIS K7113 is 10 MPa.
  • JIS K7113 examples of the thermoplastic resin material
  • a tensile fracture elongation specified by JIS K7113 of 50% or more and a Vicat softening temperature (Method A) specified by JIS K7206 of 130 ° C. or more can be used.
  • the tensile elastic modulus (specified in JIS K7113: 1995) of the resin 32 covering the reinforcing cord 30 is preferably 100 MPa or more.
  • the upper limit of the tensile modulus of the resin 32 that covers the reinforcing cord 30 is preferably set to 1000 MPa or less.
  • the tensile elastic modulus of the resin 32 covering the reinforcing cord 30 is particularly preferably in the range of 200 to 700 MPa.
  • the thickness t 1 (see FIG. 2A) of the belt 26 of the present embodiment is preferably larger than the diameter dimension of the reinforcing cord 30.
  • the reinforcing cord 30 is completely embedded in the resin 32.
  • the thickness t 1 of the belt 26 is preferably 0.70 mm or more.
  • the vicinity of the end portion 26A in the tire width direction of the belt 26 is covered and restrained by a belt-like layer 38 from the outer side in the tire radial direction.
  • the layer 38 preferably covers at least the outermost reinforcing cord 30 in the tire width direction of the belt 26 from the outer side in the tire radial direction, and further preferably covers a curved portion of the belt 26.
  • the layer 38 covers the end portion 26A of the belt 26 from the outer side in the tire width direction. Note that the layer 38 extends outward in the tire width direction from the end portion 26A of the belt 26.
  • a plurality of cords 40 arranged in parallel and coated with a rubber material 42 can be used.
  • the cord used for the layer 38 include an organic fiber cord and a steel cord.
  • a cord having a lower bending rigidity than the cord used for the belt 26, in other words, a cord thinner than the cord used for the belt 26 can be used.
  • the rubber material 42 used for the layer 38 a material having a tensile elastic modulus intermediate between the resin 32 covering the reinforcing cord 30, the rubber material constituting the side rubber layers 24A and 24B, and the rubber material constituting the tread portion 36 is used. Can do.
  • the rigidity distribution in the tire width direction there is a large difference in rigidity between the belt 26 in which the reinforcing cord 30 is embedded and the tread portion 36 made of only rubber, in other words, the difference in rigidity is large. Stress is likely to concentrate at a portion where the rigidity changes greatly, such as near the end portion 26A of the belt 26.
  • the rigidity can be gradually changed from the end portion 26A of the belt 26 to the tread portion 36 when viewed in the tire width direction. It is possible to suppress the concentration of stress in the vicinity of the end portion 26A.
  • a buffer layer 44 is provided between the layer 38 and the belt 26.
  • the buffer layer 44 serves to buffer the force received by the belt 26 from the layer 38 disposed on the outer side in the tire radial direction, and may be formed of a material having a lower tensile elastic modulus than the resin 32 of the belt 26. preferable.
  • the material for forming the buffer layer 44 may be a material having elasticity, and may be a rubber material or a resin material.
  • the buffer layer 44 of this embodiment is formed of a rubber material.
  • the layer 38 of this embodiment since the cord 40 is covered with the rubber material 42 and the buffer layer 44 is formed of the rubber material, the layer 38 and the buffer layer 44 are bonded to each other, and the bonding between the two is performed. Strength can be increased.
  • the thickness t 2 of the buffer layer 44 is preferably set within a range of 0.1 to 1.0 mm.
  • a tread portion 36 made of the second rubber material is disposed outside the belt 26 in the tire radial direction.
  • a conventionally known material is used as the second rubber material used for the tread portion 36.
  • a drainage groove 37 is formed in the tread portion 36. Further, a conventionally known pattern is used for the tread portion 36 as well.
  • the width BW of the belt 26 measured along the tire axial direction is preferably 75% or more with respect to the contact width TW of the tread portion 36 measured along the tire axial direction.
  • the upper limit of the width BW of the belt 26 is preferably 110% with respect to the ground contact width TW.
  • the contact width TW of the tread portion 36 means that the pneumatic tire 10 is mounted on a standard rim prescribed in JATMA YEAR BOOK (2018 version, Japan Automobile Pneumatic Tire Association Standard), and in JATMA YEAR BOOK Filled with 100% internal pressure of the air pressure (maximum air pressure) corresponding to the maximum load capacity (bold load in the internal pressure-load capacity correspondence table) for the applicable size and ply rating, and the rotating shaft is stationary against a horizontal flat plate It is a thing when it arrange
  • the TRA standard or ETRTO standard is applied at the place of use or manufacturing, the respective standards are followed.
  • the in-plane shear rigidity of the belt 26 is preferably equal to or higher than that of a belt having a conventional structure in which a cord is covered with rubber.
  • the belt 26 is formed by spirally winding a resin-coated cord 34 in which two reinforcing cords 30 are coated with a coating resin 32 around a belt forming drum (not shown). At that time, the resin-coated cords 34 are welded adjacent to each other.
  • the cross-sectional shape of the resin-coated cord 34 according to the present embodiment is a rectangle (horizontal width rectangle), but the resin-coated cord 34 may be any cross-sectional shape that is joined adjacent to each other. It may be a shape.
  • the resin coating cord 34 is welded adjacent to each other, thereby forming a resin layer as an example of the present invention in which the reinforcing cord 30 is embedded.
  • the belt 26, which has been cooled and solidified by the resin 32, is removed from the belt forming drum and placed outside the tire case 25 in the radial direction of the tire forming drum, and pressure is applied from the inside to expand the unvulcanized tire case 25.
  • the outer peripheral surface of the tire case 25, in other words, the outer peripheral surface of the carcass 16 is crimped to the inner peripheral surface of the belt 26.
  • the buffer layer 44 and the layer 38 are pasted so as to cover both ends of the belt 26.
  • an unvulcanized tread portion 36 is attached to the outer peripheral surface of the belt 26 in the same manner as in the production of a general pneumatic tire, and the raw tire is completed.
  • the raw tire produced in this way is vulcanized and molded with a vulcanization mold in the same manner as a general pneumatic tire, and the pneumatic tire 10 is completed.
  • the layer 38 including the cord 40 is disposed on the outer side in the tire radial direction near the end portion 26A of the belt 26, and the vicinity of the end portion 26A of the belt 26 is constrained by the layer 38. . Strictly speaking, the belt 26 is restrained by the cord 40 of the layer 38.
  • the resin 32 of the belt 26 receives a force F directed inward in the tire radial direction from the cord 40 of the layer 38 ( Note that the force F increases as the rotation increases), and the resin 32 may cause a crack C in a portion that receives the force F (as an example, directly below the cord 40).
  • the buffer layer 44 is provided between the layer 38 and the belt 26, the force F from the cord 40 of the layer 38 is applied to the buffer layer. It is buffered at 44, in other words, dispersed and acting on the belt 26, thereby suppressing the concentration of stress and suppressing the occurrence of cracks in the resin 32 of the belt 26.
  • the thickness t 2 of the buffer layer 44 is preferably set in the range of 0.1 to 1.0 mm.
  • the crown portion of the carcass 16 is reinforced by a belt 26 in which a reinforcing cord 30 spirally wound is covered with a resin 32, so that two conventional pneumatic tires are used.
  • the belt is lighter and easier to manufacture.
  • the tensile elastic modulus of the resin 32 covering the reinforcing cord 30 is 100 MPa or more and the thickness is 0.7 mm or more, in-plane shearing of the belt 26 in the tire width direction is achieved. Sufficient rigidity can be ensured.
  • the out-of-plane bending rigidity of the belt 26 is ensured, when a large lateral force is input to the pneumatic tire 10, the buckling of the tread portion 36 (the surface of the tread portion 36 undulates and a part of the road surface Phenomenon).
  • the belt 26 having high in-plane shear rigidity is used, and the width BW of the belt 26 is set to 75% or more of the ground contact width TW of the tread portion 36. Stiffness can be increased.
  • the thickness of the belt 26 can be reduced as compared with the case where the belt 26 is constituted by two or more conventional belt plies.
  • the thickness of the groove 37 can be increased, and the depth of the groove 37 can be increased. Thereby, the lifetime of the pneumatic tire 10 can be extended.
  • the reinforcing cord 30 is wound spirally, a portion overlapping the reinforcing cord 30 in the tire radial direction on the circumference without, the thickness t 1 in the tire circumferential direction is uniform Therefore, the pneumatic tire 10 is excellent in uniformity.
  • the thickness t 1 of the belt 26 in other words, the thickness of the resin 32 is less than 0.7 mm, there is a possibility that the reinforcing cord 30 embedded in the resin 32 is thickened and the tag effect cannot be obtained.
  • width BW of the belt 26 is less than 75% with respect to the ground contact width TW of the tread portion 36, it is difficult to suppress the effect of the belt 26 or to suppress the generation of noise near the shoulder 39. There is a risk of becoming.
  • the width BW of the belt 26 exceeds 110% with respect to the ground contact width TW of the tread portion 36, the tagging effect will reach a peak state, the belt 26 will be more than necessary, and the weight of the pneumatic tire 10 will increase.
  • the resin-coated cord 34 used for manufacturing the belt 26 is obtained by coating the two reinforcing cords 30 with the resin 32.
  • the resin-coated cord 34 has one reinforcing cord 30. It may be one that is coated with the resin 32, or three or more reinforcing cords 30 that are covered with the resin 32.
  • the belt 26 only needs to include at least a resin layer continuous from one end side to the other end side in the width direction, and the arrangement of the cord, the thickness of the layer, and the like are not limited to those of the above embodiment. Further, the belt 26 may not include the reinforcing cord 30 as long as strength is ensured (that is, only the resin layer).
  • the layer 38 covers only the vicinity of the end portion 26A of the belt 26.
  • the entire belt 26 is covered from the outside in the tire radial direction with at least one layer 38 formed wide.
  • the layer 38 that covers only the vicinity of the end portion 26A and the wide layer 38 that covers the entire belt 26 may be used in combination.
  • the buffer layer 44 may be provided in the whole lower part of the layer 38, and may be arrange

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

Abstract

A pneumatic tire according to the present invention comprises: a carcass extending from one bead to the other bead; a belt disposed on the outer side of the carcass in a tire radial direction and including at least a resin layer; a layer covering at least an end portion of the belt in a tire width direction; and a buffer layer disposed between the carcass and the layer.

Description

空気入りタイヤPneumatic tire
　本開示は、樹脂層を備えたベルトを有する空気入りタイヤに関する。 The present disclosure relates to a pneumatic tire having a belt provided with a resin layer.
　自動車に装着する空気入りタイヤとして、カーカスのタイヤ径方向外側に樹脂層を含んで構成されたベルトを備えた空気入りタイヤがある（例えば、特開２００７－０６９７４５号公報、特開２００２－００２２２０号公報） As pneumatic tires to be mounted on automobiles, there are pneumatic tires including a belt configured to include a resin layer on the outer side in the tire radial direction of the carcass (for example, JP 2007-069745 A, JP 2002-002220 A). (Publication)
　ベルトの端部を覆うように、レイヤーと呼ばれる補強層を設ける場合があるが、レイヤーの影響で、レイヤーで覆われたベルトの樹脂層に亀裂が入る場合があった。 In some cases, a reinforcing layer called a layer is provided so as to cover the end of the belt, but the resin layer of the belt covered with the layer may crack due to the effect of the layer.
　本開示は上記事実を考慮し、ベルトの樹脂層における亀裂の発生を抑制できる空気入りタイヤの提供を目的とする。 The present disclosure is intended to provide a pneumatic tire that can suppress the occurrence of cracks in the resin layer of the belt in consideration of the above facts.
　本開示に係る空気入りタイヤは、一方のビード部から他方のビード部に跨るカーカスと、前記カーカスのタイヤ径方向外側に配置され少なくとも樹脂層を含んで構成されたベルトと、少なくとも前記ベルトのタイヤ幅方向の端部を覆うレイヤーと、前記カーカスと前記レイヤーとの間に配置される緩衝層と、を有する。 A pneumatic tire according to the present disclosure includes a carcass straddling one bead portion to the other bead portion, a belt that is disposed on the outer side in the tire radial direction of the carcass and includes at least a resin layer, and at least the tire of the belt A layer covering an end portion in the width direction; and a buffer layer disposed between the carcass and the layer.
　本開示に係る空気入りタイヤでは、レイヤーとベルトとの間に緩衝層が設けられているため、レイヤーからの力を緩衝層で緩衝することができ、ベルトの樹脂層において亀裂の発生を抑制することが出来る。 In the pneumatic tire according to the present disclosure, since the buffer layer is provided between the layer and the belt, the force from the layer can be buffered by the buffer layer, and the occurrence of cracks in the resin layer of the belt is suppressed. I can do it.
　以上説明したように本開示の空気入りタイヤによれば、ベルトの樹脂層における亀裂の発生を抑制できる、という優れた効果を有する。 As described above, according to the pneumatic tire of the present disclosure, there is an excellent effect that the occurrence of cracks in the resin layer of the belt can be suppressed.
本発明の一実施形態に係る空気入りタイヤを示すタイヤ回転軸に沿った断面図である。It is sectional drawing along the tire rotating shaft which shows the pneumatic tire which concerns on one Embodiment of this invention. レイヤー、緩衝層、及びベルトを示すショルダー付近の断面図である。It is sectional drawing of the shoulder vicinity which shows a layer, a buffer layer, and a belt. 緩衝層の無いベルト、及びレイヤーを示す断面図である。It is sectional drawing which shows the belt and layer without a buffer layer. レイヤー、緩衝層、及びベルトを示す断面図である。It is sectional drawing which shows a layer, a buffer layer, and a belt.
　図１、及び図２Ａ，２Ｃを用いて、本発明の一実施形態に係る空気入りタイヤ１０について説明する。
　図１に示すように、本実施形態の空気入りタイヤ１０は、例えば、乗用車に用いられる所謂ラジアル空気入りタイヤであり、ビードコア１２が埋設された一対のビード部２０を備え、一方のビード部２０と他方のビード部２０との間に、１枚のカーカスプライ１４からなるカーカス１６が跨っている。なお、図１は、標準リム１９に取り付けた空気入りタイヤ１０の空気充填前（内圧＝大気圧）の自然状態の形状を示している。 A pneumatic tire 10 according to an embodiment of the present invention will be described with reference to FIGS. 1 and 2A and 2C.
As shown in FIG. 1, the pneumatic tire 10 of the present embodiment is a so-called radial pneumatic tire used for a passenger car, for example, and includes a pair of bead portions 20 in which a bead core 12 is embedded, and one bead portion 20. 1 and the other bead portion 20 is straddling a carcass 16 composed of one carcass ply 14. FIG. 1 shows the natural state of the pneumatic tire 10 attached to the standard rim 19 before filling with air (internal pressure = atmospheric pressure).
　カーカスプライ１４は、空気入りタイヤ１０のラジアル方向に延びる複数本のコード（図示せず）をコーティングゴム（図示せず）で被覆して形成されている。即ち、本実施形態の空気入りタイヤ１０は、所謂ラジアル空気入りタイヤである。カーカスプライ１４のコードの材料は、例えば、ＰＥＴであるが、従来公知の他の材料であっても良い。 The carcass ply 14 is formed by coating a plurality of cords (not shown) extending in the radial direction of the pneumatic tire 10 with a coating rubber (not shown). That is, the pneumatic tire 10 of the present embodiment is a so-called radial pneumatic tire. The material of the cord of the carcass ply 14 is, for example, PET, but may be another conventionally known material.
　カーカスプライ１４は、タイヤ幅方向の端部分がビードコア１２をタイヤ径方向外側に折り返されている。カーカスプライ１４は、一方のビードコア１２から他方のビードコア１２に跨る部分が本体部１４Ａと呼ばれ、ビードコア１２から折り返されている部分が折り返し部１４Ｂと呼ばれる。 The end portion of the carcass ply 14 in the tire width direction is folded back from the bead core 12 in the tire radial direction. In the carcass ply 14, a portion extending from one bead core 12 to the other bead core 12 is called a main body portion 14 </ b> A, and a portion folded from the bead core 12 is called a folded portion 14 </ b> B.
　本実施形態の空気入りタイヤ１０におけるカーカスプライ１４の本体部１４Ａの断面形状は、従来一般の空気入りタイヤと同様の断面形状であり、タイヤ赤道面ＣＬ付近は半径が略一定で平坦な形状であり、ショルダー付近において半径が漸減している。 The cross-sectional shape of the main body portion 14A of the carcass ply 14 in the pneumatic tire 10 of the present embodiment is the same cross-sectional shape as that of a conventional general pneumatic tire, and the vicinity of the tire equatorial plane CL has a substantially constant radius and a flat shape. Yes, the radius gradually decreases near the shoulder.
　カーカスプライ１４の本体部１４Ａと折返し部１４Ｂとの間には、ビードコア１２からタイヤ径方向外側に向けて厚さが漸減するビードフィラー１８が配置されている。なお、本実施形態の空気入りタイヤ１０において、ビードフィラー１８のタイヤ径方向外側端１８Ａからタイヤ径方向内側の部分がビード部２０とされている。 Between the main body part 14A and the turn-up part 14B of the carcass ply 14, a bead filler 18 whose thickness gradually decreases from the bead core 12 toward the outer side in the tire radial direction is disposed. In the pneumatic tire 10 of the present embodiment, a bead portion 20 is a portion on the inner side in the tire radial direction from the tire radial direction outer end 18A of the bead filler 18.
　カーカス１６の空気入りタイヤ内側にはゴムからなるインナーライナー２２が配置されている。一方、カーカス１６のタイヤ幅方向外側には、タイヤ径方向外側にサイドゴム層２４Ａが、タイヤ径方向内側にサイドゴム層２４Ｂが配置されている。なお、サイドゴム層２４Ｂは、一部分がビードコア１２の径方向内側を折り返してタイヤ内面の一部まで延びている。 An inner liner 22 made of rubber is disposed inside the pneumatic tire of the carcass 16. On the other hand, on the outer side in the tire width direction of the carcass 16, a side rubber layer 24A is disposed on the outer side in the tire radial direction, and a side rubber layer 24B is disposed on the inner side in the tire radial direction. Note that a part of the side rubber layer 24 </ b> B is folded back on the radially inner side of the bead core 12 and extends to a part of the tire inner surface.
　本実施形態では、ビードコア１２、カーカス１６、ビードフィラー１８、インナーライナー２２、サイドゴム層２４Ａ、及びサイドゴム層２４Ｂによってタイヤケース２５が構成されている。タイヤケース２５は、言い換えれば、空気入りタイヤ１０の骨格を成す空気入りタイヤ骨格部材のことである。 In the present embodiment, a tire case 25 is configured by the bead core 12, the carcass 16, the bead filler 18, the inner liner 22, the side rubber layer 24A, and the side rubber layer 24B. In other words, the tire case 25 is a pneumatic tire frame member that forms the frame of the pneumatic tire 10.
（ベルト）
　カーカス１６のクラウン部の外側、言い換えればカーカス１６のタイヤ径方向外側には、カーカス１６の外周部を拘束してタガ効果を得るためのベルト２６が配置されている。本実施形態のベルト２６は、回転軸に沿った断面で見たときに、ほぼ全体が平坦に形成されている、言い換えれば、タイヤ幅方向中央部分がタイヤ回転軸に平行な直線状に形成されているが、タイヤ幅方向両端部分はタイヤ径方向内側へ若干湾曲している。
　なお、ベルト２６のタイヤ幅方向両端部分の湾曲の程度は、カーカス１６の湾曲の程度に比較して小さい。したがって、ベルト２６は、タイヤ幅方向中央部側の殆どの部分がカーカス１６の外周面に密着しているが、幅方向両側の一部分はカーカス１６の外周面から離間している。 (belt)
A belt 26 is provided on the outer side of the crown portion of the carcass 16, in other words, on the outer side in the tire radial direction of the carcass 16 to restrain the outer peripheral portion of the carcass 16 to obtain a tag effect. The belt 26 of the present embodiment is formed substantially flat when viewed in a cross section along the rotation axis. In other words, the central portion in the tire width direction is formed in a straight line parallel to the tire rotation axis. However, both end portions in the tire width direction are slightly curved inward in the tire radial direction.
It should be noted that the degree of curvature of both ends of the belt 26 in the tire width direction is smaller than the degree of curvature of the carcass 16. Therefore, most of the belt 26 is in close contact with the outer peripheral surface of the carcass 16 at the center in the tire width direction, but a part of both sides in the width direction is separated from the outer peripheral surface of the carcass 16.
　本実施形態のベルト２６は、複数本（本実施形態では２本）の補強コード３０を樹脂３２で被覆した樹脂被覆コード３４に巻回することで形成されている。なお、ベルト２６の製法方法は後述する。
　ベルト２６の補強コード３０は、カーカスプライ１４のコードよりも太く、かつ、強力（引張強度）が大きいものを用いることが好ましい。ベルト２６の補強コード３０は、金属繊維や有機繊維等のモノフィラメント（単線）、又はこれらの繊維を撚ったマルチフィラメント（撚り線）で構成することができる。本実施形態の補強コード３０は、スチールコードである。補強コード３０としては、例えば、直径が０．２２５ｍｍの“１×５”のスチールコードを用いることができるが、従来公知の他の構造のスチールコードを用いることもできる。 The belt 26 of the present embodiment is formed by winding a plurality (two in the present embodiment) of reinforcing cords 30 around a resin-coated cord 34 covered with a resin 32. A method for manufacturing the belt 26 will be described later.
The reinforcing cord 30 of the belt 26 is preferably thicker than the cord of the carcass ply 14 and has a high strength (tensile strength). The reinforcing cord 30 of the belt 26 can be composed of monofilament (single wire) such as metal fiber or organic fiber, or multifilament (twisted wire) obtained by twisting these fibers. The reinforcing cord 30 of the present embodiment is a steel cord. As the reinforcing cord 30, for example, a “1 × 5” steel cord having a diameter of 0.225 mm can be used, but a steel cord having another structure that is conventionally known can also be used.
　補強コード３０を被覆する樹脂３２には、サイドゴム層２４Ａ，２４Ｂを構成するゴム材料、及び後述するトレッド部３６を構成するゴム材料よりも引張弾性率の高い樹脂材料が用いられている。補強コード３０を被覆する樹脂３２としては、弾性を有する熱可塑性樹脂、熱可塑性エラストマー（ＴＰＥ）、及び熱硬化性樹脂等を用いることができる。走行時の弾性と製造時の成形性を考慮すると、熱可塑性エラストマーを用いることが望ましい。 The resin 32 that covers the reinforcing cord 30 is made of a rubber material that constitutes the side rubber layers 24A and 24B and a resin material that has a higher tensile elastic modulus than a rubber material that constitutes the tread portion 36 described later. As the resin 32 covering the reinforcing cord 30, an elastic thermoplastic resin, a thermoplastic elastomer (TPE), a thermosetting resin, or the like can be used. In consideration of elasticity during running and moldability during production, it is desirable to use a thermoplastic elastomer.
　熱可塑性エラストマーとしては、ポリオレフィン系熱可塑性エラストマー（ＴＰＯ）、ポリスチレン系熱可塑性エラストマー（ＴＰＳ）、ポリアミド系熱可塑性エラストマー（ＴＰＡ）、ポリウレタン系熱可塑性エラストマー（ＴＰＵ）、ポリエステル系熱可塑性エラストマー（ＴＰＣ）、動的架橋型熱可塑性エラストマー（ＴＰＶ）等が挙げられる。 As thermoplastic elastomers, polyolefin-based thermoplastic elastomer (TPO), polystyrene-based thermoplastic elastomer (TPS), polyamide-based thermoplastic elastomer (TPA), polyurethane-based thermoplastic elastomer (TPU), polyester-based thermoplastic elastomer (TPC) And dynamic crosslinkable thermoplastic elastomer (TPV).
　また、熱可塑性樹脂としては、ポリウレタン樹脂、ポリオレフィン樹脂、塩化ビニル樹脂、ポリアミド樹脂等が挙げられる。さらに、熱可塑性樹脂材料としては、例えば、ＩＳＯ７５－２又はＡＳＴＭ　Ｄ６４８に規定されている荷重たわみ温度（０．４５ＭＰａ荷重時）が７８°Ｃ以上、ＪＩＳ　Ｋ７１１３に規定される引張降伏強さが１０ＭＰａ以上、同じくＪＩＳ　Ｋ７１１３に規定される引張破壊伸びが５０％以上、ＪＩＳ　Ｋ７２０６に規定されるビカット軟化温度（Ａ法）が１３０°Ｃ以上であるものを用いることができる。 Further, examples of the thermoplastic resin include polyurethane resin, polyolefin resin, vinyl chloride resin, polyamide resin and the like. Further, as the thermoplastic resin material, for example, the deflection temperature under load (when 0.45 MPa is loaded) specified in ISO 75-2 or ASTM D648 is 78 ° C or higher, and the tensile yield strength specified in JIS K7113 is 10 MPa. As described above, those having a tensile fracture elongation specified by JIS K7113 of 50% or more and a Vicat softening temperature (Method A) specified by JIS K7206 of 130 ° C. or more can be used.
　補強コード３０を被覆する樹脂３２の引張弾性率（ＪＩＳ　Ｋ７１１３：１９９５に規定される）は、１００ＭＰａ以上が好ましい。また、補強コード３０を被覆する樹脂３２の引張弾性率の上限は、１０００ＭＰａ以下とすることが好ましい。なお、補強コード３０を被覆する樹脂３２の引張弾性率は、２００～７００ＭＰａの範囲内が特に好ましい。 The tensile elastic modulus (specified in JIS K7113: 1995) of the resin 32 covering the reinforcing cord 30 is preferably 100 MPa or more. In addition, the upper limit of the tensile modulus of the resin 32 that covers the reinforcing cord 30 is preferably set to 1000 MPa or less. The tensile elastic modulus of the resin 32 covering the reinforcing cord 30 is particularly preferably in the range of 200 to 700 MPa.
　本実施形態のベルト２６の厚さｔ１（図２Ａ参照）は、補強コード３０の直径寸法よりも大きくすることが好ましい、言い換えれば、補強コード３０が完全に樹脂３２に埋設されていることが好ましい。ベルト２６の厚さｔ１は、空気入りタイヤ１０が乗用車用の場合、具体的には、０.７０ｍｍ以上とすることが好ましい。 The thickness t 1 (see FIG. 2A) of the belt 26 of the present embodiment is preferably larger than the diameter dimension of the reinforcing cord 30. In other words, the reinforcing cord 30 is completely embedded in the resin 32. preferable. Specifically, when the pneumatic tire 10 is for a passenger car, the thickness t 1 of the belt 26 is preferably 0.70 mm or more.
（レイヤー）
　ベルト２６のタイヤ幅方向の端部２６Ａ付近は、帯状のレイヤー３８でタイヤ径方向外側から覆われて拘束されている。レイヤー３８は、少なくともベルト２６におけるタイヤ幅方向最外側の補強コード３０をタイヤ径方向外側から覆うことが好ましく、さらには、ベルト２６の湾曲している部分を覆うことが好ましい。また、レイヤー３８は、ベルト２６の端部２６Ａをタイヤ幅方向外側から覆っている。なお、レイヤー３８は、ベルト２６の端部２６Ａよりもタイヤ幅方向外側に延びている。 (layer)
The vicinity of the end portion 26A in the tire width direction of the belt 26 is covered and restrained by a belt-like layer 38 from the outer side in the tire radial direction. The layer 38 preferably covers at least the outermost reinforcing cord 30 in the tire width direction of the belt 26 from the outer side in the tire radial direction, and further preferably covers a curved portion of the belt 26. The layer 38 covers the end portion 26A of the belt 26 from the outer side in the tire width direction. Note that the layer 38 extends outward in the tire width direction from the end portion 26A of the belt 26.
　レイヤー３８としては、例えば、図２Ａに示すように、複数本のコード４０を平行に並べてゴム材料４２でコーティングしたものを用いることができる。レイヤー３８に用いるコードとしては、例えば、有機繊維コード、スチールコードを挙げることができる。レイヤー３８にスチールコードを用いる場合、ベルト２６に用いるコードよりも曲げ剛性の低いもの、言い換えれば、ベルト２６に用いるコードよりも細いものを用いることができる。 As the layer 38, for example, as shown in FIG. 2A, a plurality of cords 40 arranged in parallel and coated with a rubber material 42 can be used. Examples of the cord used for the layer 38 include an organic fiber cord and a steel cord. In the case of using a steel cord for the layer 38, a cord having a lower bending rigidity than the cord used for the belt 26, in other words, a cord thinner than the cord used for the belt 26 can be used.
　レイヤー３８に用いるゴム材料４２は、補強コード３０を被覆する樹脂３２とサイドゴム層２４Ａ，２４Ｂを構成するゴム材料及びトレッド部３６を構成するゴム材料との中間の引張弾性率を有するものを用いることができる。 As the rubber material 42 used for the layer 38, a material having a tensile elastic modulus intermediate between the resin 32 covering the reinforcing cord 30, the rubber material constituting the side rubber layers 24A and 24B, and the rubber material constituting the tread portion 36 is used. Can do.
　剛性分布をタイヤ幅方向に見て、補強コード３０が埋設されたベルト２６とゴムのみからなるトレッド部３６との間では、剛性段差が大きい、言い換えれば、剛性の差が大きい。ベルト２６の端部２６Ａ付近等、剛性が大きく変化する部位では、応力が集中し易い。本実施形態の空気入りタイヤ１０では、ベルト２６の端部２６Ａをレイヤー３８で覆うことで、タイヤ幅方向に見て、ベルト２６の端部２６Ａからトレッド部３６にかけて剛性を徐々に変化させることができ、端部２６Ａ付近の応力の集中を抑制することができる。 Referring to the rigidity distribution in the tire width direction, there is a large difference in rigidity between the belt 26 in which the reinforcing cord 30 is embedded and the tread portion 36 made of only rubber, in other words, the difference in rigidity is large. Stress is likely to concentrate at a portion where the rigidity changes greatly, such as near the end portion 26A of the belt 26. In the pneumatic tire 10 of the present embodiment, by covering the end portion 26A of the belt 26 with the layer 38, the rigidity can be gradually changed from the end portion 26A of the belt 26 to the tread portion 36 when viewed in the tire width direction. It is possible to suppress the concentration of stress in the vicinity of the end portion 26A.
（緩衝層）　
　本実施形態の空気入りタイヤ１０では、レイヤー３８とベルト２６との間に緩衝層４４が設けられている。
　緩衝層４４は、ベルト２６が、タイヤ径方向外側に配置されたレイヤー３８から受ける力を緩衝する役目をするものであり、ベルト２６の樹脂３２よりも引張弾性率の低い材料で形成することが好ましい。緩衝層４４を形成する材料は、弾性を有している材料であればよく、ゴム材料であってもよく、樹脂材料であってもよい。本実施形態の緩衝層４４は、ゴム材料で形成されている。
　本実施形態のレイヤー３８では、コード４０がゴム材料４２で被覆されており、緩衝層４４がゴム材料で形成されているため、レイヤー３８と緩衝層４４とはゴム同士の接合となり、両者の接合強度を高める事が出来る。
　なお、緩衝層４４の厚みｔ２は、０．１～１．０ｍｍの範囲内に設定することが好ましい。 (Buffer layer)
In the pneumatic tire 10 of the present embodiment, a buffer layer 44 is provided between the layer 38 and the belt 26.
The buffer layer 44 serves to buffer the force received by the belt 26 from the layer 38 disposed on the outer side in the tire radial direction, and may be formed of a material having a lower tensile elastic modulus than the resin 32 of the belt 26. preferable. The material for forming the buffer layer 44 may be a material having elasticity, and may be a rubber material or a resin material. The buffer layer 44 of this embodiment is formed of a rubber material.
In the layer 38 of this embodiment, since the cord 40 is covered with the rubber material 42 and the buffer layer 44 is formed of the rubber material, the layer 38 and the buffer layer 44 are bonded to each other, and the bonding between the two is performed. Strength can be increased.
The thickness t 2 of the buffer layer 44 is preferably set within a range of 0.1 to 1.0 mm.
（トレッド）
　ベルト２６のタイヤ径方向外側には、第２のゴム材料からなるトレッド部３６が配置されている。トレッド部３６に用いる第２のゴム材料は、従来一般公知のものが用いられる。トレッド部３６には、排水用の溝３７が形成されている。また、トレッド部３６のパターンも従来一般公知のものが用いられる。 (tread)
A tread portion 36 made of the second rubber material is disposed outside the belt 26 in the tire radial direction. As the second rubber material used for the tread portion 36, a conventionally known material is used. A drainage groove 37 is formed in the tread portion 36. Further, a conventionally known pattern is used for the tread portion 36 as well.
　タイヤ軸方向に沿って計測するベルト２６の幅ＢＷは、タイヤ軸方向に沿って計測するトレッド部３６の接地幅ＴＷに対して７５％以上とすることが好ましい。なお、ベルト２６の幅ＢＷの上限は、接地幅ＴＷに対して１１０％とすることが好ましい。 The width BW of the belt 26 measured along the tire axial direction is preferably 75% or more with respect to the contact width TW of the tread portion 36 measured along the tire axial direction. The upper limit of the width BW of the belt 26 is preferably 110% with respect to the ground contact width TW.
　ここで、トレッド部３６の接地幅ＴＷとは、空気入りタイヤ１０をＪＡＴＭＡ ＹＥＡＲ ＢＯＯＫ（２０１８年度版、日本自動車空気入りタイヤ協会規格）に規定されている標準リムに装着し、ＪＡＴＭＡ　ＹＥＡＲ　ＢＯＯＫでの適用サイズ・プライレーティングにおける最大負荷能力（内圧－負荷能力対応表の太字荷重）に対応する空気圧（最大空気圧）の１００％の内圧を充填し、静止した状態で水平な平板に対して回転軸が平行となるように配置し、最大の負荷能力に対応する質量を加えたときのものである。なお、使用地又は製造地において、ＴＲＡ規格、ＥＴＲＴＯ規格が適用される場合は各々の規格に従う。 Here, the contact width TW of the tread portion 36 means that the pneumatic tire 10 is mounted on a standard rim prescribed in JATMA YEAR BOOK (2018 version, Japan Automobile Pneumatic Tire Association Standard), and in JATMA YEAR BOOK Filled with 100% internal pressure of the air pressure (maximum air pressure) corresponding to the maximum load capacity (bold load in the internal pressure-load capacity correspondence table) for the applicable size and ply rating, and the rotating shaft is stationary against a horizontal flat plate It is a thing when it arrange | positions so that it may become parallel and adds the mass corresponding to the maximum load capability. When the TRA standard or ETRTO standard is applied at the place of use or manufacturing, the respective standards are followed.
　なお、ベルト２６の面内剪断剛性は、コードをゴムで被覆した従来構造のベルト以上であることが好ましい。 The in-plane shear rigidity of the belt 26 is preferably equal to or higher than that of a belt having a conventional structure in which a cord is covered with rubber.
（空気入りタイヤの製造方法）
　次に、本実施形態の空気入りタイヤ１０の製造方法の一例を説明する。
　公知のタイヤ成形ドラム（不図示）の外周に、ゴム材料（未加硫）からなるインナーライナー２２、ビードコア１２、コードをゴム材料（未加硫）で被覆したカーカスプライ１４、ゴム材料（未加硫）からなるビードフィラー１８、サイドゴム層（未加硫）２４Ａ、サイドゴム層（未加硫）２４Ｂを貼り付けて未加硫のタイヤケース２５を形成する。 (Pneumatic tire manufacturing method)
Next, an example of the manufacturing method of the pneumatic tire 10 of this embodiment is demonstrated.
An outer periphery of a known tire molding drum (not shown), an inner liner 22 made of a rubber material (unvulcanized), a bead core 12, a carcass ply 14 in which a cord is coated with a rubber material (unvulcanized), a rubber material (unvulcanized) A bead filler 18, a side rubber layer (unvulcanized) 24 A, and a side rubber layer (unvulcanized) 24 B are attached to form an unvulcanized tire case 25.
　ベルト２６は、２本の補強コード３０を被覆用の樹脂３２で被覆した樹脂被覆コード３４をベルト成形ドラム（不図示）に螺旋状に巻回して形成する。その際、樹脂被覆コード３４は隣接する同士で溶着させる。本実施形態の樹脂被覆コード３４の断面形状は矩形（横幅の長方形）であるが、樹脂被覆コード３４は隣接する同士で接合される断面形状であればよく、例えば、平行四辺形等の他の形状であってもよい。
　このように、樹脂被覆コード３４は隣接する同士で溶着させることで、補強コード３０が埋設された本発明の一例としての樹脂層が形成される。 The belt 26 is formed by spirally winding a resin-coated cord 34 in which two reinforcing cords 30 are coated with a coating resin 32 around a belt forming drum (not shown). At that time, the resin-coated cords 34 are welded adjacent to each other. The cross-sectional shape of the resin-coated cord 34 according to the present embodiment is a rectangle (horizontal width rectangle), but the resin-coated cord 34 may be any cross-sectional shape that is joined adjacent to each other. It may be a shape.
Thus, the resin coating cord 34 is welded adjacent to each other, thereby forming a resin layer as an example of the present invention in which the reinforcing cord 30 is embedded.
　次に、樹脂３２が冷却されて固化したベルト２６をベルト成形ドラムから取り外してタイヤ成形ドラムのタイヤケース２５の径方向外側に配置し、内側から圧力を掛けて未加硫のタイヤケース２５を拡張する。これにより、タイヤケース２５の外周面、言い換えればカーカス１６の外周面をベルト２６の内周面に圧着する。 Next, the belt 26, which has been cooled and solidified by the resin 32, is removed from the belt forming drum and placed outside the tire case 25 in the radial direction of the tire forming drum, and pressure is applied from the inside to expand the unvulcanized tire case 25. To do. As a result, the outer peripheral surface of the tire case 25, in other words, the outer peripheral surface of the carcass 16 is crimped to the inner peripheral surface of the belt 26.
　その後、ベルト２６の両端部を覆う様に緩衝層４４、及びレイヤー３８を貼り付ける。最後に、ベルト２６の外周面に、一般の空気入りタイヤの製造と同様に、未加硫のトレッド部３６を貼り付け、生タイヤが完成する。 Thereafter, the buffer layer 44 and the layer 38 are pasted so as to cover both ends of the belt 26. Finally, an unvulcanized tread portion 36 is attached to the outer peripheral surface of the belt 26 in the same manner as in the production of a general pneumatic tire, and the raw tire is completed.
　このようにして製造された生タイヤは、一般の空気入りタイヤと同様に加硫成形モールドで加硫成形され、空気入りタイヤ１０が完成する。 The raw tire produced in this way is vulcanized and molded with a vulcanization mold in the same manner as a general pneumatic tire, and the pneumatic tire 10 is completed.
（作用、効果）
　次に、本実施形態の空気入りタイヤ１０の作用、効果を説明する。 (Function, effect)
Next, functions and effects of the pneumatic tire 10 of the present embodiment will be described.
　本実施形態の空気入りタイヤ１０では、ベルト２６の端部２６Ａ付近のタイヤ径方向外側にコード４０を含むレイヤー３８が配置されており、ベルト２６の端部２６Ａ付近がレイヤー３８で拘束されている。厳密には、ベルト２６は、レイヤー３８のコード４０によって拘束されている。 In the pneumatic tire 10 of the present embodiment, the layer 38 including the cord 40 is disposed on the outer side in the tire radial direction near the end portion 26A of the belt 26, and the vicinity of the end portion 26A of the belt 26 is constrained by the layer 38. . Strictly speaking, the belt 26 is restrained by the cord 40 of the layer 38.
　図２Ｂに示すように、ベルト２６の外周面に、レイヤー３８が直接貼り付けられている場合、ベルト２６の樹脂３２は、レイヤー３８のコード４０からタイヤ径方向内側へ向かう力Ｆを受けるため（なお、回転の上昇に伴い力Ｆは増大する）、樹脂３２は、力Ｆを受けた部位（一例として、コード４０の直下）に亀裂Ｃを生じる場合がある。 As shown in FIG. 2B, when the layer 38 is directly attached to the outer peripheral surface of the belt 26, the resin 32 of the belt 26 receives a force F directed inward in the tire radial direction from the cord 40 of the layer 38 ( Note that the force F increases as the rotation increases), and the resin 32 may cause a crack C in a portion that receives the force F (as an example, directly below the cord 40).
　一方、本実施形態の空気入りタイヤ１０では、図２Ｃに示すように、レイヤー３８とベルト２６との間に緩衝層４４が設けられているため、レイヤー３８のコード４０からの力Ｆが緩衝層４４で緩衝され、言い換えれば分散されてベルト２６に作用することで応力の集中が抑制され、ベルト２６の樹脂３２において亀裂の発生を抑制することが出来る。 On the other hand, in the pneumatic tire 10 of the present embodiment, as shown in FIG. 2C, since the buffer layer 44 is provided between the layer 38 and the belt 26, the force F from the cord 40 of the layer 38 is applied to the buffer layer. It is buffered at 44, in other words, dispersed and acting on the belt 26, thereby suppressing the concentration of stress and suppressing the occurrence of cracks in the resin 32 of the belt 26.
　なお、緩衝層４４の厚みｔ２が薄すぎると、力Ｆを緩衝する効果が不足して亀裂の発生を抑制することが困難となる。緩衝層４４の厚みｔ２は、ある程度あれば亀裂の発生を抑制することができ、必要以上に厚くすると、緩衝層４４の材料使用量が増え、重量が無駄に増加する。このため、緩衝層４４の厚みｔ２は、０．１～１．０ｍｍの範囲に設定することが好ましい。 Incidentally, if the thickness t 2 of the buffer layer 44 is too thin, it becomes difficult to suppress the occurrence of cracks is insufficient the effect of cushioning the force F. The thickness t 2 of the buffer layer 44, it is possible to suppress the occurrence of cracks if some degree, when the thickness more than necessary, increased material usage of the buffer layer 44, the weight is increased wastefully. For this reason, the thickness t 2 of the buffer layer 44 is preferably set in the range of 0.1 to 1.0 mm.
　本実施形態の空気入りタイヤ１０では、カーカス１６のクラウン部が、螺旋状に巻回された補強コード３０が樹脂３２で被覆されたベルト２６で補強されているため、従来空気入りタイヤの２枚以上のベルトプライから構成された複数層からなるベルトに比較して軽量となり、製造も簡単になっている。 In the pneumatic tire 10 of the present embodiment, the crown portion of the carcass 16 is reinforced by a belt 26 in which a reinforcing cord 30 spirally wound is covered with a resin 32, so that two conventional pneumatic tires are used. Compared to a belt composed of a plurality of layers composed of the above belt plies, the belt is lighter and easier to manufacture.
　本実施形態のベルト２６は、補強コード３０を被覆している樹脂３２の引張弾性率が１００ＭＰａ以上とされ、厚みも０．７ｍｍ以上確保されているので、ベルト２６のタイヤ幅方向の面内剪断剛性を十分に確保することができる。 In the belt 26 of the present embodiment, since the tensile elastic modulus of the resin 32 covering the reinforcing cord 30 is 100 MPa or more and the thickness is 0.7 mm or more, in-plane shearing of the belt 26 in the tire width direction is achieved. Sufficient rigidity can be ensured.
　ベルト２６の面内剪断剛性が確保されることで、空気入りタイヤ１０にスリップ角を付与した場合の横力を十分に発生させることができ、操縦安定性を確保することができ、また、応答性も向上させることができる。 By ensuring the in-plane shear rigidity of the belt 26, it is possible to sufficiently generate a lateral force when a slip angle is applied to the pneumatic tire 10, to ensure steering stability, and to respond. Can also be improved.
　また、ベルト２６の面外曲げ剛性が確保されることで、空気入りタイヤ１０に大きな横力が入力した際、トレッド部３６のバックリング（トレッド部３６の表面が波打って、一部が路面から離間する現象）を抑制することができる。 Further, since the out-of-plane bending rigidity of the belt 26 is ensured, when a large lateral force is input to the pneumatic tire 10, the buckling of the tread portion 36 (the surface of the tread portion 36 undulates and a part of the road surface Phenomenon).
　さらに、本実施形態の空気入りタイヤ１０では、面内剪断剛性が高いベルト２６を用いており、ベルト２６の幅ＢＷをトレッド部３６の接地幅ＴＷの７５％以上としているので、ショルダー３９付近の剛性を高めることができる。 Furthermore, in the pneumatic tire 10 of the present embodiment, the belt 26 having high in-plane shear rigidity is used, and the width BW of the belt 26 is set to 75% or more of the ground contact width TW of the tread portion 36. Stiffness can be increased.
　本実施形態の空気入りタイヤ１０では、ベルト２６が１層構造であるため、従来の２枚以上のベルトプライで構成した場合に比較して、ベルト２６の厚みを薄くでき、その分トレッド部３６の厚みを厚くすることができ、かつ溝３７の深さを深くすることができる。これにより、空気入りタイヤ１０の寿命を延ばすことも可能となる。 In the pneumatic tire 10 of the present embodiment, since the belt 26 has a single layer structure, the thickness of the belt 26 can be reduced as compared with the case where the belt 26 is constituted by two or more conventional belt plies. The thickness of the groove 37 can be increased, and the depth of the groove 37 can be increased. Thereby, the lifetime of the pneumatic tire 10 can be extended.
　空気入りタイヤ１０におけるベルト２６は、補強コード３０が螺旋状に巻回され、周上で補強コード３０がタイヤ径方向に重なる部分が無く、タイヤ周方向に厚さｔ１が均一となっているので、空気入りタイヤ１０はユニフォミティーに優れたものとなる。 Belt 26 in the pneumatic tire 10, the reinforcing cord 30 is wound spirally, a portion overlapping the reinforcing cord 30 in the tire radial direction on the circumference without, the thickness t 1 in the tire circumferential direction is uniform Therefore, the pneumatic tire 10 is excellent in uniformity.
　ベルト２６の厚みｔ１、言い換えれば樹脂３２の厚みが０．７ｍｍ未満になると、樹脂３２中に埋設する補強コード３０を太くしてタガ効果を得ることができなくなる虞がある。 If the thickness t 1 of the belt 26, in other words, the thickness of the resin 32 is less than 0.7 mm, there is a possibility that the reinforcing cord 30 embedded in the resin 32 is thickened and the tag effect cannot be obtained.
　また、ベルト２６の幅ＢＷがトレッド部３６の接地幅ＴＷに対して７５％未満となると、ベルト２６のタガ効果が不十分となったり、ショルダー３９付近の騒音の発生を抑制することが困難になる虞がある。一方、ベルト２６の幅ＢＷがトレッド部３６の接地幅ＴＷに対して１１０％を超えると、タガ効果としては頭打ち状態となり、ベルト２６が必要以上となり、空気入りタイヤ１０の重量増加を招く。 Further, when the width BW of the belt 26 is less than 75% with respect to the ground contact width TW of the tread portion 36, it is difficult to suppress the effect of the belt 26 or to suppress the generation of noise near the shoulder 39. There is a risk of becoming. On the other hand, if the width BW of the belt 26 exceeds 110% with respect to the ground contact width TW of the tread portion 36, the tagging effect will reach a peak state, the belt 26 will be more than necessary, and the weight of the pneumatic tire 10 will increase.
［その他の実施形態］
　以上、本発明の一実施形態について説明したが、本発明は、上記に限定されるものでなく、上記以外にも、その主旨を逸脱しない範囲内において種々変形して実施可能であることは勿論である。 [Other Embodiments]
Although one embodiment of the present invention has been described above, the present invention is not limited to the above, and other various modifications can be made without departing from the spirit of the present invention. It is.
　上記実施形態では、ベルト２６を製造する際に用いた樹脂被覆コード３４が、２本の補強コード３０を樹脂３２で被覆したものであったが、樹脂被覆コード３４は１本の補強コード３０を樹脂３２で被覆したものであってもよく、３本以上の補強コード３０を樹脂３２で被覆したものであってもよい。 In the above embodiment, the resin-coated cord 34 used for manufacturing the belt 26 is obtained by coating the two reinforcing cords 30 with the resin 32. However, the resin-coated cord 34 has one reinforcing cord 30. It may be one that is coated with the resin 32, or three or more reinforcing cords 30 that are covered with the resin 32.
　なお、ベルト２６は、少なくとも幅方向の一端側から他端側まで連続した樹脂層を備えていればよく、コードの配置、層の厚み等は上記実施形態のものに限定されない。
　また、ベルト２６は、強度が確保されれば補強コード３０が含まれていなくてもよい（即ち樹脂層のみ）。 The belt 26 only needs to include at least a resin layer continuous from one end side to the other end side in the width direction, and the arrangement of the cord, the thickness of the layer, and the like are not limited to those of the above embodiment.
Further, the belt 26 may not include the reinforcing cord 30 as long as strength is ensured (that is, only the resin layer).
　上記実施形態では、レイヤー３８でベルト２６の端部２６Ａ付近のみを覆ったが、必要に応じて、幅広に形成した少なくとも１枚のレイヤー３８でベルト２６の全体をタイヤ径方向外側から覆うようにしてもよく、端部２６Ａ付近のみを覆うレイヤー３８とベルト２６の全体を覆う幅広のレイヤー３８とを組み合わせて用いてもよい。
　ベルト２６の全体をレイヤー３８で覆う場合、緩衝層４４は、レイヤー３８の下方全体に設けてもよく、亀裂の発生し易い箇所に対応した部分のみに配置してもよい。 In the above embodiment, the layer 38 covers only the vicinity of the end portion 26A of the belt 26. However, if necessary, the entire belt 26 is covered from the outside in the tire radial direction with at least one layer 38 formed wide. Alternatively, the layer 38 that covers only the vicinity of the end portion 26A and the wide layer 38 that covers the entire belt 26 may be used in combination.
When covering the whole belt 26 with the layer 38, the buffer layer 44 may be provided in the whole lower part of the layer 38, and may be arrange | positioned only in the part corresponding to the location where a crack is easy to generate | occur | produce.
　　２０１８年６月１５日に出願された日本国特許出願２０１８－１１４３２７号の開示は、その全体が参照により本明細書に取り込まれる。
　本明細書に記載されたすべての文献、特許出願、及び技術規格は、個々の文献、特許出願、及び技術規格が参照により取り込まれることが具体的かつ個々に記された場合と同程度に、本明細書中に参照により取り込まれる。 The disclosure of Japanese Patent Application No. 2018-114327 filed on June 15, 2018 is incorporated herein by reference in its entirety.
All documents, patent applications, and technical standards mentioned in this specification are to the same extent as if each individual document, patent application, and technical standard were specifically and individually stated to be incorporated by reference, Incorporated herein by reference.

Claims (4)

  1. 　一方のビード部から他方のビード部に跨るカーカスと、
    　前記カーカスのタイヤ径方向外側に配置され少なくとも樹脂層を含んで構成されたベルトと、
    　少なくとも前記ベルトのタイヤ幅方向の端部を覆うレイヤーと、
    　前記カーカスと前記レイヤーとの間に配置される緩衝層と、
    　を有する空気入りタイヤ。     A carcass straddling one bead portion to the other bead portion;
    A belt arranged outside the carcass in the tire radial direction and including at least a resin layer;
    A layer covering at least an end of the belt in the tire width direction;
    A buffer layer disposed between the carcass and the layer;
    Pneumatic tire having
  2. 　前記緩衝層は、前記樹脂層を構成する樹脂よりも弾性率の低い材料で形成されている、請求項１に記載の空気入りタイヤ。 The pneumatic tire according to claim 1, wherein the buffer layer is formed of a material having a lower elastic modulus than a resin constituting the resin layer.
  3. 　前記弾性率の低い材料は、ゴムである、請求項２に記載の空気入りタイヤ。 The pneumatic tire according to claim 2, wherein the material having a low elastic modulus is rubber.
  4. 　前記緩衝層の厚みは０．１～１．０ｍｍの範囲内に設定されている、請求項１～請求項３の何れか１項に記載の空気入りタイヤ。 The pneumatic tire according to any one of claims 1 to 3, wherein a thickness of the buffer layer is set within a range of 0.1 to 1.0 mm.
PCT/JP2019/021328 2018-06-15 2019-05-29 Pneumatic tire WO2019239895A1 (en)

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JP2006044487A (en) * 2004-08-05 2006-02-16 Yokohama Rubber Co Ltd:The Pneumatic radial tire
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* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US5082713A (en) * 1990-07-23 1992-01-21 Pirelli Armstrong Tire Corporation Wide monofilament reinforcing cords employing high performance thermoplastics and tire belts made therefrom
JP2002331806A (en) * 2001-05-09 2002-11-19 Yokohama Rubber Co Ltd:The Pneumatic tire using thermoplastic elastomer coated steel cord
JP2006044487A (en) * 2004-08-05 2006-02-16 Yokohama Rubber Co Ltd:The Pneumatic radial tire
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JP2017517429A (en) * 2014-04-29 2017-06-29 コンパニー ゼネラール デ エタブリッスマン ミシュラン Multi-composite planar reinforcement
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