WO2015186654A1 - Heavy duty tire - Google Patents

Heavy duty tire Download PDF

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Publication number
WO2015186654A1
WO2015186654A1 PCT/JP2015/065753 JP2015065753W WO2015186654A1 WO 2015186654 A1 WO2015186654 A1 WO 2015186654A1 JP 2015065753 W JP2015065753 W JP 2015065753W WO 2015186654 A1 WO2015186654 A1 WO 2015186654A1
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WO
WIPO (PCT)
Prior art keywords
tire
carcass ply
radial direction
tire radial
heavy duty
Prior art date
Application number
PCT/JP2015/065753
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French (fr)
Japanese (ja)
Inventor
淳 福島
由和 木林
祐司 小山
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 WO2015186654A1 publication Critical patent/WO2015186654A1/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
    • B60C15/00—Tyre beads, e.g. ply turn-up or overlap
    • 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
    • B60C15/00—Tyre beads, e.g. ply turn-up or overlap
    • B60C15/06—Flipper strips, fillers, or chafing strips and reinforcing layers for the construction of the bead
    • D—TEXTILES; PAPER
    • D07—ROPES; CABLES OTHER THAN ELECTRIC
    • D07B—ROPES OR CABLES IN GENERAL
    • D07B1/00—Constructional features of ropes or cables
    • D07B1/06—Ropes or cables built-up from metal wires, e.g. of section wires around a hemp core

Definitions

  • the present invention relates to a heavy duty tire in which a carcass ply is folded at a bead core.
  • a pneumatic tire is widely known in which both ends of a carcass ply straddling a pair of bead cores are folded back by bead cores.
  • two carcass plies are arranged in an up-down structure, and the ply end of the folded portion of the carcass ply (the end on the outer side in the tire radial direction) is connected to another carcass ply from the outside of the tire.
  • the present invention has been made in view of the above problems, and it is an object of the present invention to provide a heavy duty tire in which internal pressure holding performance and bead portion durability performance are ensured even with a simple structure in which one carcass ply is arranged.
  • the present inventor has examined a tire structure that can ensure the durability of the bead portion without covering the ply end of the folded portion of the carcass ply with another carcass ply from the outside of the tire.
  • the present inventor created a prototype, conducted experiments and analysis calculations, repeated further studies, and completed the present invention.
  • the invention according to the first aspect of the present invention is such that the carcass ply cord has a fineness in the range of 5100 to 9000 dtex and an elongation of 3.6 to 5.3 at a load of 2 cN / dtex.
  • the carcass ply has a rigidity in the range of 6%, the carcass ply is folded back outward in the tire width direction so as to wrap the bead core made of steel cord, and the folded part of the carcass ply is arranged along the carcass ply main body.
  • the outer end in the tire radial direction of the outer bead filler located on the outer side in the tire width direction is positioned on the outer side in the tire radial direction from the outer end in the tire radial direction of the folded portion, and the rubber chafer is located on the outer side in the tire width direction of the outer bead filler.
  • the tire radial direction outside and gradually decreases in thickness of the rubber chafer, sidewall portion, and summarized in that disposed along the carcass ply main body while in contact with the rubber chafer.
  • FIG. 1 is a tire radial direction sectional view showing a configuration of a heavy duty tire according to a first embodiment of the present invention.
  • 2A is a tire radial direction cross-sectional view showing a bead portion in the heavy load tire according to the first embodiment of the present invention
  • FIG. 2B is a heavy load tire according to the first embodiment of the present invention.
  • FIG. 2 is a schematic tire radial direction cross-sectional view illustrating a force applied to a thin rubber portion sandwiched between a carcass ply body and a folded portion of a carcass ply.
  • FIG. 3 is a tire radial direction cross-sectional view showing a bead portion in a heavy duty tire according to a second embodiment of the present invention.
  • FIG. 4 is a graph showing the relationship between the turn-up height of the carcass ply end and the ply end separate measure in an experimental example.
  • FIG. 5 is an explanatory diagram for explaining the results of the analysis calculation example.
  • FIG. 1 is a tire radial direction sectional view showing a configuration of a heavy duty tire (pneumatic tire) according to a first embodiment (hereinafter referred to as this embodiment) of the present invention.
  • 2A is a tire radial direction cross-sectional view showing a bead portion in the heavy load tire according to the present embodiment
  • FIG. 2B is a view of the carcass ply body and the carcass ply in the heavy load tire according to the present embodiment.
  • the shape of the bead core or the like is different from that in FIG. 1, but the basic concept is the same.
  • the heavy-duty tire 10 of the present embodiment is suitable as a tire (LT) used for a light truck, and is an optimal tire for use at a working internal pressure of 400 to 600 kPa.
  • the heavy load tire 10 includes a pair of bead cores 12, a high-strength carcass ply 14 straddling the pair of bead cores 12, and a belt 15 disposed outside the carcass ply 14 in the tire radial direction.
  • the carcass ply 14 is composed of one sheet.
  • the heavy load tire 10 has a structure in which the tread portion 20, the shoulder portion 22, the sidewall portion (tire side portion) 24, and the bead portion 26 are sequentially provided from the outer side in the tire radial direction.
  • the bead core 12 is made of a steel cord.
  • the cord of the carcass ply 14 has a fineness in the range of 5100 to 9000 dtex, and has a rigidity in a range of 3.6 to 5.6% in elongation at a load of 2 cN / dtex.
  • the carcass ply 14 is folded outward in the tire width direction so as to wrap the bead core 12 composed of a steel cord, and a folded portion 14r of the carcass ply 14 is disposed along the carcass ply main body 14m.
  • the outer bead filler 16 is located on the outer side in the tire width direction of the folded portion 14r of the carcass ply 14, and the outer end 16u in the tire radial direction of the outer bead filler 16 (the upper end of the outer bead filler 16 in FIG. 1). Is located on the outer side in the tire radial direction from the outer end 14ru in the tire radial direction of the folded portion 14r.
  • the rubber chafer 18 is located outside the outer bead filler 16 in the tire width direction, and is in contact with the rim flange RF and the outer bead filler 16. In the rubber chafer 18, the thickness of the rubber chafer 18 gradually decreases on the outer side in the tire radial direction from the separation point K from the rim flange RF.
  • the sidewall portion 24 is disposed along the carcass ply main body 14m while being in contact with the rubber chafer 18, so that the sidewall portion 24 covers a portion of the rubber chafer 18 on the outer side in the tire radial direction from the outer side of the tire. It has become.
  • the carcass ply 14 is folded back so as to wrap the bead core 12, and the folded portion 14r of the carcass ply 14 is disposed along the carcass ply main body 14m.
  • the rubber sandwiched between the carcass ply main body 14m and the folded portion 14r is a thin rubber portion GT as shown in FIGS. 2 (a) and 2 (b), for example.
  • the thin rubber portion GT is formed by vulcanization molding of a rubber material previously coated on the surface of the cord constituting the carcass ply 14.
  • the thin rubber portion GT (see FIGS. 2A and 2B) has a side portion GTm that contacts the carcass ply body 14m and a side portion GTr that contacts the folded portion 14r. Forces in opposite directions act on each other.
  • the force applied from the bead core 12 to the carcass ply 14 acts as a force for deforming the thin rubber portion GT, and accordingly, the thin rubber portion GT and the rubber on the opposite side sandwiching the folded portion 14r with the thin rubber portion GT.
  • the force acting as a force for peeling off the folded portion 14r from the portion GE is reduced.
  • the bead core 12 is formed of a steel cord and the tire configuration is such that the number of carcass plies 14 is one, damage occurs at the bead portion 26 at the outer end 14ru (ply end) in the tire radial direction of the folded portion 14r. This can be sufficiently prevented. That is, even if the configuration is simplified, the heavy-duty tire 10 that ensures both the basic performance (internal pressure holding performance) as the pressure vessel and the durability performance of the bead portion 26 can be obtained.
  • the bead core 12 can be made of a steel cord, it is possible to obtain an effect that the tire weight can be greatly reduced as compared with the case where the bead core is made of a steel cord.
  • the cord of the carcass ply 14 can have a fineness in the range of 5100 to 9000 dtex and a rigidity in a range of 3.6 to 5.6% in elongation at a load of 2 cN / dtex.
  • the outer bead filler 16 is positioned on the outer side in the tire width direction of the folded portion 14r of the carcass ply 14, and the tire radial direction outer end 16u of the outer bead filler 16 is more than the tire radial direction outer end 14ru of the folded portion 14r. Is also located on the outer side in the tire radial direction. Further, the rubber chafer 18 is positioned on the outer side in the tire width direction of the outer bead filler 16 and is in contact with the rim flange RF and the outer bead filler 16.
  • the outer end 16u of the outer bead filler 16 in the tire radial direction is covered with the rubber chafer 18 from the outer side of the tire, and the outer bead filler 16 is not in contact with the rim flange RF.
  • the end portion of the sidewall portion 24 on the inner side in the tire radial direction is located outside the tire of the rubber chafer 18, and the sidewall portion 24 covers the portion of the rubber chafer 18 on the outer side in the tire radial direction. ing.
  • FIG. 3 is a tire radial direction cross-sectional view showing a bead portion in a heavy duty tire according to a second embodiment of the present invention.
  • an inner bead filler 16s is arranged, and the carcass ply 14 is folded outward in the tire width direction so as to wrap the inner bead filler 16s and the bead core 12.
  • One end portion of the folded portion 14r of the carcass ply 14 that is located on the outer side in the tire radial direction and has a predetermined length is disposed along the carcass ply main body 14m, and one end portion of the folded portion 14r of the carcass ply 14 is disposed. The remaining part except for is sandwiched between the inner bead filler 16s and the outer bead filler 16t.
  • the inner bead filler 16s is positioned on the inner side in the tire width direction of the folded portion 14r of the carcass ply 14, and the inner bead filler 16s is positioned between the carcass ply main body 14m and the folded portion 14r of the carcass ply 14. . Further, the outer bead filler 16t is located on the outer side in the tire width direction of the folded portion 14r of the carcass ply 14.
  • the outer end 16u in the tire radial direction of the outer bead filler 16t is located on the outer side in the tire radial direction from the outer end 14ru in the tire radial direction of the folded portion 14r.
  • the tire radial direction outer end 16su of the inner bead filler 16s is located on the inner side in the tire radial direction of the tire radial direction outer end 14ru of the folded portion 14r of the carcass ply 14. Moreover, when the length along the tire radial direction from the tire radial direction outer end of the bead core to the tire radial direction outer end of the inner bead filler 16s is defined as a height hsb of the inner bead filler 16s (see FIG. 3), The height hsb of the inner bead filler 16s is in the range of 10 to 20 mm.
  • this embodiment is different from the first embodiment in that the inner bead filler 16s is disposed, but the other configurations are the same as those of the first embodiment.
  • the outer end 16su in the tire radial direction of the inner bead filler 16s is located on the inner side in the tire radial direction with respect to the outer end 14ru in the tire radial direction of the folded portion 14r of the carcass ply 14.
  • a predetermined length of one end portion of the folded portion 14r located on the outer side in the tire radial direction can be ensured.
  • a thin rubber portion GT having a predetermined length can be formed between the carcass ply main body 14m and one end of the folded portion 14r.
  • a force of relative movement along the carcass ply main body 14m acts on the folded portion 14r, and the carcass ply main body acts on the thin rubber portion GT. Forces in opposite directions act on the side surface portion GTm in contact with the 14m side and the side surface portion GTr in contact with the folded portion 14r side.
  • the height hsb (see FIG. 3) of the inner bead filler 16s is preferably in the range of 10 to 20 mm.
  • the folding height hr (ply folding height; see FIGS. 1 and 2A) of the folded portion 14r is preferably 23 to 40 mm. With such a configuration, it is possible to ensure a predetermined length of one end portion located on the outer side in the tire radial direction of the folded portion 14r of the carcass ply 14.
  • the present embodiment is an embodiment in which the cord strength of the carcass ply 14 is 5.0 cN / dtex or more and the treat strength is 3.3 kN / cm or more in the configuration shown in the above-described plurality of embodiments. According to the present embodiment, the strength of the carcass ply 14 can be sufficiently increased.
  • the folding height hr (ply folding height; see FIGS. 1 and 2A) of the folding portion 14r is in the range of 23 to 40 mm. It is. By setting the folding height hr in the range of 23 to 40 mm, it is possible to effectively prevent the occurrence of damage at the outer end 14ru (ply end) in the tire radial direction of the folded portion 14r.
  • the folded height hr of the folded portion 14r of the carcass ply 14 is defined as follows. That is, as shown in FIG. 1 and FIG. 2A, in the tire radial direction cross section, it passes through the cross-sectional center C of the bead core 12 and forms an angle ⁇ of 45 ° in both the horizontal direction X and the vertical direction Y.
  • a straight line toward the tire center axis side on the tire outer side is defined as a reference straight line S
  • a tire radial direction distance from an intersection P between the reference straight line S and the folded portion 14r to a tire radial outer end 14ru of the folded portion 14r is The folding height is hr.
  • the folded height hr is a height when a normal rim is attached to the heavy load tire 10 and a normal internal pressure is applied.
  • “regular rim” refers to the standard rim specified in the following standards according to the tire size
  • “regular internal pressure” refers to the single wheel at the applicable size described in the following standards.
  • the air pressure corresponding to the maximum load capacity is referred to
  • the “normal load” refers to the maximum load (maximum load capacity) of a single wheel in the applicable size of the following standard.
  • the standard is an industrial standard that is effective in the area where tires are produced or used.
  • the present embodiment is an embodiment in which the height hb (see FIG. 1) of the outer bead filler 16 is in the range of 25 to 40 mm in the configuration shown in the plurality of embodiments described above.
  • the height hb in the range of 25 to 40 mm, it is possible to make it easy to ensure the durability of the bead portion 26 sufficiently.
  • the height hb of the outer bead filler 16 refers to the distance in the tire radial direction from the tire radial inner end 16b of the outer bead filler 16 to the tire radial outer end 16u.
  • the tire radial outer end 18 u of the rubber chafer 18 is higher than the tire radial outer end 16 u of the outer bead filler 16.
  • the distance hg is arranged on the outer side in the tire radial direction.
  • the height hg is in the range of 0 to 15 mm, preferably in the range of 5 to 15 mm. According to the present embodiment, it is possible to effectively prevent the outer bead filler 16 from being damaged from the tire radial direction outer end 16u while maintaining the strength of the bead portion 26.
  • the evaluation of the strain generated in the tire is performed by multiplying the average strain and the amplitude strain and taking into consideration both, and the smaller the value, the better the evaluation.
  • the tire having a turnback height hb of 38 mm has a relatively large amplitude distortion
  • the tire having a turnback height hb of 18 mm has a relatively large average distortion.
  • the evaluation was that the tire with the folding height hb of 28 mm was the best.
  • the folding height hb of the folded portion 14r of the carcass ply 14 is preferably in the range of 23 to 40 mm.
  • the inventor has an example of a conventional heavy duty tire for a light truck (hereinafter referred to as a conventional example), an example of a first embodiment (hereinafter referred to as an example), and a first implementation.
  • a heavy duty tire hereinafter referred to as a comparative example
  • the inner bead filler 46 is disposed inside the carcass ply 44 (between the carcass ply main body and the folded portion of the carcass ply) is referred to as a ply by analytical calculation.
  • the value of the edge sepa measure was calculated.
  • the analysis conditions and analysis results are also shown in FIG.
  • the conventional example two carcass plies 84a and 84b are arranged, and the end portion (ply end) of the folded portion 84r of the carcass ply 84a inside the tire is covered with the carcass ply 84b outside the tire.
  • the ply strength of the carcass plies 84a and 84b of the conventional example is 100
  • the ply strength of the carcass ply 14 is 180
  • the strength of the carcass plies 84a and 84b is almost twice as high.
  • the carcass ply 44 of the comparative example is also assumed to have a ply strength of 180.
  • the example, and the comparative example an example in which the bead core is formed of a steel cord is assumed.
  • FIG. 5 shows that the generated distortion is sequentially increased in the order of the dot hatch area, the hatched hatch area, and the mesh hatch area.
  • the ply end sepa major is 0.02.
  • the ply end separator major is 0.12.
  • the ply end sepa major is 0.04.
  • the carcass ply 14 is folded outward in the tire width direction so as to wrap the bead core 12 made of a steel cord, the folded portion 14r is disposed along the carcass ply body 14m, and the outer bead filler 16 is folded. 14r is arranged outside in the tire width direction.
  • the structure in which one high-strength carcass ply 14 is disposed as the carcass ply results in that the ply end separator measure does not need to be raised (deteriorated) much compared to the conventional example.
  • SYMBOLS 10 Heavy load tire, 12 ... Bead core, 14 ... Carcass ply, 14m ... Carcass ply main body, 14r ... Turn-up part, 14ru ... Tire radial direction outer end, 16, 16t ... Outer bead filler, 16s ... Inner bead filler, 16u ... Tire radial outer end, 18 ... rubber chafer, 18u ... tire radial outer end, 24 ... sidewall, hb ... height, hr ... folding height, RF ... rim flange

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

Abstract

A carcass ply (14) is turned back so as to envelope bead cores (12) consisting of steel cords, and the turned-back portions (14r) of the carcass ply (14) are arranged along the carcass ply body (14m). The outer ends (16u), in the radial direction of the tire, of outer bead fillers (16, 16t) located outside the turned-back portions (14r) in the width direction of the tire are located on the outside, in the radial direction of the tire, of the outer ends (14ru), in the radial direction of the tire, of the turned-back portions (14r). Rubber chafers (18) are located outside the outer bead fillers (16, 16t) in the width direction of the tire and are in contact with rim flanges (RF) and the outer bead fillers (16, 16t). The thickness of the rubber chafers (18) gradually decreases outside separation points (K) in the radial direction of the tire, the separation points (K) being those at which the rubber chafers (18) separate from the rim flanges (RF). Sidewall sections (24) are in contact with the rubber chafers (18).

Description

重荷重用タイヤHeavy duty tire
　本発明は、カーカスプライがビードコアで折り返された重荷重用タイヤに関する。 The present invention relates to a heavy duty tire in which a carcass ply is folded at a bead core.
　一対のビードコアを跨るカーカスプライの両端部がそれぞれビードコアで折り返された空気入りタイヤが広く知られている。
このような空気入りタイヤでは、通常、２枚のカーカスプライをアップダウン構造で配置してカーカスプライの折り返し部分のプライ端（タイヤ径方向外側の端部）をタイヤ外側からもう１枚のカーカスプライで覆う構造にしている（例えば特許文献１参照）。 A pneumatic tire is widely known in which both ends of a carcass ply straddling a pair of bead cores are folded back by bead cores.
In such a pneumatic tire, normally, two carcass plies are arranged in an up-down structure, and the ply end of the folded portion of the carcass ply (the end on the outer side in the tire radial direction) is connected to another carcass ply from the outside of the tire. (See, for example, Patent Document 1).
特開２０１１－２０７３１９号公報JP 2011-207319 A
　近年の空気入りタイヤでは、構造の簡素化、軽量化が益々進展してきている。従って、カーカスプライの配置枚数が１枚で済むのであれば、簡素化、軽量化の観点で好ましい。このことは、乗用車用タイヤに限らず重荷重用タイヤ（特に小型トラック用のタイヤ）であっても同様である。
本発明は上記課題に鑑みてなされたものであり、１枚のカーカスプライを配置する簡素な構造にしても内圧保持性能とビード部耐久性能とが確保された重荷重用タイヤを提供することを課題とする。 In recent pneumatic tires, the simplification of the structure and the weight reduction have been made more and more. Therefore, if only one carcass ply is arranged, it is preferable from the viewpoint of simplification and weight reduction. This applies not only to passenger car tires but also to heavy-duty tires (particularly light truck tires).
The present invention has been made in view of the above problems, and it is an object of the present invention to provide a heavy duty tire in which internal pressure holding performance and bead portion durability performance are ensured even with a simple structure in which one carcass ply is arranged. And
　本発明者は、カーカスプライの折り返し部分のプライ端をタイヤ外側からもう１枚のカーカスプライで覆わなくてもビード部耐久性を確保できるようなタイヤ構造にすることを検討した。 The present inventor has examined a tire structure that can ensure the durability of the bead portion without covering the ply end of the folded portion of the carcass ply with another carcass ply from the outside of the tire.
　そして、カーカスプライの枚数を１枚に低減した場合にカーカスプライの折り返し部分で発生する応力に着目し、この応力を低減させ、しかもカーカスプライがビード部から抜け難い構造とすることを鋭意検討した。 Then, paying attention to the stress generated in the folded portion of the carcass ply when the number of carcass plies is reduced to one, we have intensively studied to reduce this stress and make it difficult for the carcass ply to come out of the bead portion. .
　そして、本発明者は、試作品を作成し、実験や解析計算を行い、更に検討を重ね、本発明を完成するに至った。 Then, the present inventor created a prototype, conducted experiments and analysis calculations, repeated further studies, and completed the present invention.
　上述した課題を解決するため、本発明の第１の特徴に係る発明は、カーカスプライのコードは、５１００～９０００ｄｔｅｘの範囲の繊度を有し、２ｃＮ／ｄｔｅｘ荷重時の伸び３．６～５．６％となる範囲の剛性を有し、カーカスプライはスチールコードで構成されるビードコアを包み込むようにタイヤ幅方向外側へ折り返されてカーカスプライの折り返し部分がカーカスプライ本体に沿って配置され、折り返し部分のタイヤ幅方向外側に位置する外側ビードフィラーのタイヤ径方向外側端は、折り返し部分のタイヤ径方向外側端よりもタイヤ径方向外側に位置し、ゴムチェーファーが、外側ビードフィラーのタイヤ幅方向外側に位置してリムフランジと外側ビードフィラーとに接し、ゴムチェーファーとリムフランジとの離反点よりもタイヤ径方向外側ではゴムチェーファーの厚みが漸減しており、サイドウォール部が、ゴムチェーファーに接しつつカーカスプライ本体に沿って配置されていることを要旨とする。 In order to solve the above-described problem, the invention according to the first aspect of the present invention is such that the carcass ply cord has a fineness in the range of 5100 to 9000 dtex and an elongation of 3.6 to 5.3 at a load of 2 cN / dtex. The carcass ply has a rigidity in the range of 6%, the carcass ply is folded back outward in the tire width direction so as to wrap the bead core made of steel cord, and the folded part of the carcass ply is arranged along the carcass ply main body. The outer end in the tire radial direction of the outer bead filler located on the outer side in the tire width direction is positioned on the outer side in the tire radial direction from the outer end in the tire radial direction of the folded portion, and the rubber chafer is located on the outer side in the tire width direction of the outer bead filler. Located on the rim flange and the outer bead filler, and more than the separation point between the rubber chafer and the rim flange. The tire radial direction outside and gradually decreases in thickness of the rubber chafer, sidewall portion, and summarized in that disposed along the carcass ply main body while in contact with the rubber chafer.
図１は、本発明の第１実施形態に係る重荷重用タイヤの構成を示すタイヤ径方向断面図である。FIG. 1 is a tire radial direction sectional view showing a configuration of a heavy duty tire according to a first embodiment of the present invention. 図２（ａ）は、本発明の第１実施形態に係る重荷重用タイヤにおけるビード部を示すタイヤ径方向断面図、図２（ｂ）は、本発明の第１実施形態に係る重荷重用タイヤにおいて、カーカスプライ本体とカーカスプライの折り返し部分とに挟まれた薄厚ゴム部分に加えられる力を説明する模式的なタイヤ径方向断面図である。2A is a tire radial direction cross-sectional view showing a bead portion in the heavy load tire according to the first embodiment of the present invention, and FIG. 2B is a heavy load tire according to the first embodiment of the present invention. FIG. 2 is a schematic tire radial direction cross-sectional view illustrating a force applied to a thin rubber portion sandwiched between a carcass ply body and a folded portion of a carcass ply. 図３は、本発明の第２実施形態に係る重荷重用タイヤにおけるビード部を示すタイヤ径方向断面図である。FIG. 3 is a tire radial direction cross-sectional view showing a bead portion in a heavy duty tire according to a second embodiment of the present invention. 図４は、実験例で、カーカスプライ端の折り返し高さとプライ端セパメジャーとの関係を示すグラフ図である。FIG. 4 is a graph showing the relationship between the turn-up height of the carcass ply end and the ply end separate measure in an experimental example. 図５は、解析計算例の結果を説明する説明図である。FIG. 5 is an explanatory diagram for explaining the results of the analysis calculation example.
　以下、添付図面を参照しつつ本発明の実施の形態を説明する。以下の説明では、同一または類似の部分には、同一又は類似の符号を付し、その詳細な説明を適宜省略している。
また、以下に示す実施の形態は、この発明の技術的思想を具体化するための例示であって、この発明の実施の形態は、構成部品の材質、形状、構造、配置等を下記のものに特定するものではない。この発明の実施の形態は、要旨を逸脱しない範囲内で種々変更して実施できる。 Hereinafter, embodiments of the present invention will be described with reference to the accompanying drawings. In the following description, the same or similar parts are denoted by the same or similar reference numerals, and detailed description thereof is omitted as appropriate.
The following embodiments are exemplifications for embodying the technical idea of the present invention, and the embodiments of the present invention are described below in terms of the material, shape, structure, arrangement, etc. of the components. It is not something specific. The embodiments of the present invention can be implemented with various modifications without departing from the scope of the invention.
　［第１実施形態］
　図１は、本発明の第１実施形態（以下、本実施形態という）に係る重荷重用タイヤ（空気入りタイヤ）の構成を示すタイヤ径方向断面図である。図２（ａ）は、本実施形態に係る重荷重用タイヤにおけるビード部を示すタイヤ径方向断面図、図２（ｂ）は、本実施形態に係る重荷重用タイヤにおける、カーカスプライ本体とカーカスプライの折り返し部分とに挟まれた薄厚ゴム部分に加えられる力を説明する模式的なタイヤ径方向断面図である。なお、図２（ａ）では、図１に比べ、ビードコアなどの形状を異ならせて描いているが、基本概念は同じである。 [First Embodiment]
FIG. 1 is a tire radial direction sectional view showing a configuration of a heavy duty tire (pneumatic tire) according to a first embodiment (hereinafter referred to as this embodiment) of the present invention. 2A is a tire radial direction cross-sectional view showing a bead portion in the heavy load tire according to the present embodiment, and FIG. 2B is a view of the carcass ply body and the carcass ply in the heavy load tire according to the present embodiment. It is typical tire radial direction sectional drawing explaining the force applied to the thin rubber part pinched | interposed by the folding | turning part. In FIG. 2A, the shape of the bead core or the like is different from that in FIG. 1, but the basic concept is the same.
　本実施形態の重荷重用タイヤ１０は、小型トラックに用いるタイヤ（ＬＴ）として好適であり、使用内圧が４００～６００ｋＰａで用いるのに最適なタイヤである。 The heavy-duty tire 10 of the present embodiment is suitable as a tire (LT) used for a light truck, and is an optimal tire for use at a working internal pressure of 400 to 600 kPa.
　重荷重用タイヤ１０は、一対のビードコア１２と、この一対のビードコア１２に跨る高強力のカーカスプライ１４と、カーカスプライ１４のタイヤ径方向外側に配置されたベルト１５とを備えている。カーカスプライ１４は１枚で構成されている。 The heavy load tire 10 includes a pair of bead cores 12, a high-strength carcass ply 14 straddling the pair of bead cores 12, and a belt 15 disposed outside the carcass ply 14 in the tire radial direction. The carcass ply 14 is composed of one sheet.
　そして、これらはゴムによって覆われており、重荷重用タイヤ１０は、トレッド部２０、ショルダー部２２、サイドウォール部（タイヤサイド部）２４、および、ビード部２６をタイヤ径方向外側から順次有する構造にされている。ビードコア１２は、スチールコードで構成されている。 These are covered with rubber, and the heavy load tire 10 has a structure in which the tread portion 20, the shoulder portion 22, the sidewall portion (tire side portion) 24, and the bead portion 26 are sequentially provided from the outer side in the tire radial direction. Has been. The bead core 12 is made of a steel cord.
　カーカスプライ１４のコードは、５１００～９０００ｄｔｅｘの範囲の繊度を有し、かつ、２ｃＮ／ｄｔｅｘ荷重時の伸びが３．６～５．６％となる範囲の剛性を有するように構成されている。そして、カーカスプライ１４は、スチールコードで構成されるビードコア１２を包み込むようにタイヤ幅方向外側へ折り返されており、カーカスプライ１４の折り返し部分１４ｒはカーカスプライ本体１４ｍに沿って配置されている。 The cord of the carcass ply 14 has a fineness in the range of 5100 to 9000 dtex, and has a rigidity in a range of 3.6 to 5.6% in elongation at a load of 2 cN / dtex. The carcass ply 14 is folded outward in the tire width direction so as to wrap the bead core 12 composed of a steel cord, and a folded portion 14r of the carcass ply 14 is disposed along the carcass ply main body 14m.
　そして、外側ビードフィラー１６が、カーカスプライ１４の折り返し部分１４ｒのタイヤ幅方向外側に位置しており、外側ビードフィラー１６のタイヤ径方向外側端１６ｕ（図１で、外側ビードフィラー１６の紙面上端）は、折り返し部分１４ｒのタイヤ径方向外側端１４ｒｕよりもタイヤ径方向外側に位置している。 The outer bead filler 16 is located on the outer side in the tire width direction of the folded portion 14r of the carcass ply 14, and the outer end 16u in the tire radial direction of the outer bead filler 16 (the upper end of the outer bead filler 16 in FIG. 1). Is located on the outer side in the tire radial direction from the outer end 14ru in the tire radial direction of the folded portion 14r.
　また、ゴムチェーファー１８が外側ビードフィラー１６のタイヤ幅方向外側に位置し、リムフランジＲＦと外側ビードフィラー１６とに接している。そして、ゴムチェーファー１８は、リムフランジＲＦとの離反点Ｋよりもタイヤ径方向外側ではゴムチェーファー１８の厚みが漸減している。 Further, the rubber chafer 18 is located outside the outer bead filler 16 in the tire width direction, and is in contact with the rim flange RF and the outer bead filler 16. In the rubber chafer 18, the thickness of the rubber chafer 18 gradually decreases on the outer side in the tire radial direction from the separation point K from the rim flange RF.
　また、サイドウォール部２４は、ゴムチェーファー１８に接しつつカーカスプライ本体１４ｍに沿って配置されており、ゴムチェーファー１８のタイヤ径方向外側の部分をサイドウォール部２４がタイヤ外側から覆う構造になっている。 Further, the sidewall portion 24 is disposed along the carcass ply main body 14m while being in contact with the rubber chafer 18, so that the sidewall portion 24 covers a portion of the rubber chafer 18 on the outer side in the tire radial direction from the outer side of the tire. It has become.
　（作用、効果）
　以下、本実施形態の作用、効果を説明する。本実施形態では、カーカスプライ１４は、ビードコア１２を包み込むように折り返されており、カーカスプライ１４の折り返し部分１４ｒはカーカスプライ本体１４ｍに沿って配置されている。従って、カーカスプライ本体１４ｍと折り返し部分１４ｒとに挟まれているゴムは、例えば図２（ａ）および図２（ｂ）に示すように薄厚ゴム部分ＧＴとなっている。なお、この薄厚ゴム部分ＧＴは、カーカスプライ１４を構成するコードの表面に予め被覆されていたゴム材が加硫成形されることで形成されたものである。 (Function, effect)
Hereinafter, the operation and effect of the present embodiment will be described. In the present embodiment, the carcass ply 14 is folded back so as to wrap the bead core 12, and the folded portion 14r of the carcass ply 14 is disposed along the carcass ply main body 14m. Accordingly, the rubber sandwiched between the carcass ply main body 14m and the folded portion 14r is a thin rubber portion GT as shown in FIGS. 2 (a) and 2 (b), for example. The thin rubber portion GT is formed by vulcanization molding of a rubber material previously coated on the surface of the cord constituting the carcass ply 14.
　よって、荷重直下に位置するビード部２６で、特にビードコア１２からタイヤ径方向内側に向けた大きな力がビードコア１２からカーカスプライ１４に加えられた際、折り返し部分１４ｒには、カーカスプライ本体１４ｍに沿って相対移動する力が作用し、薄厚ゴム部分ＧＴ（図２（ａ）および図２（ｂ）参照）には、カーカスプライ本体１４ｍ側に接する側面部ＧＴｍと折り返し部分１４ｒ側に接する側面部ＧＴｒとで互いに逆向きの力が作用する。 Therefore, when a large force is applied to the carcass ply 14 from the bead core 12 to the carcass ply 14 at the bead portion 26 located immediately below the load, the folded portion 14r is formed along the carcass ply main body 14m. Accordingly, the thin rubber portion GT (see FIGS. 2A and 2B) has a side portion GTm that contacts the carcass ply body 14m and a side portion GTr that contacts the folded portion 14r. Forces in opposite directions act on each other.
　従って、ビードコア１２からカーカスプライ１４に加えられた力は薄厚ゴム部分ＧＴを変形させる力として作用し、その分、薄厚ゴム部分ＧＴや、薄厚ゴム部分ＧＴとで折り返し部分１４ｒを挟む反対側のゴム部分ＧＥから折り返し部分１４ｒを引き剥がす力として作用する力は小さくなる。 Accordingly, the force applied from the bead core 12 to the carcass ply 14 acts as a force for deforming the thin rubber portion GT, and accordingly, the thin rubber portion GT and the rubber on the opposite side sandwiching the folded portion 14r with the thin rubber portion GT. The force acting as a force for peeling off the folded portion 14r from the portion GE is reduced.
　よって、ビードコア１２をスチールコードで構成するとともにカーカスプライ１４の配置枚数を１枚にしたタイヤ構成にしても、ビード部２６において折り返し部分１４ｒのタイヤ径方向外側端１４ｒｕ（プライ端）で損傷が生じることを充分に防止できる。すなわち、構成を簡素化しても、圧力容器としての基本性能（内圧保持性能）とビード部２６の耐久性能との両性能を確保した重荷重用タイヤ１０とすることができる。 Therefore, even when the bead core 12 is formed of a steel cord and the tire configuration is such that the number of carcass plies 14 is one, damage occurs at the bead portion 26 at the outer end 14ru (ply end) in the tire radial direction of the folded portion 14r. This can be sufficiently prevented. That is, even if the configuration is simplified, the heavy-duty tire 10 that ensures both the basic performance (internal pressure holding performance) as the pressure vessel and the durability performance of the bead portion 26 can be obtained.
　また、ビードコア１２をスチールコードで構成することができるので、ビードコアをスチールコードで構成した場合に比べ、タイヤ重量を大きく低減できるなどの効果が得られる。更に、カーカスプライ１４のコードは、５１００～９０００ｄｔｅｘの範囲の繊度で、しかも２ｃＮ／ｄｔｅｘ荷重時の伸びが３．６～５．６％となる範囲の剛性とすることができる。 In addition, since the bead core 12 can be made of a steel cord, it is possible to obtain an effect that the tire weight can be greatly reduced as compared with the case where the bead core is made of a steel cord. Furthermore, the cord of the carcass ply 14 can have a fineness in the range of 5100 to 9000 dtex and a rigidity in a range of 3.6 to 5.6% in elongation at a load of 2 cN / dtex.
　そして、外側ビードフィラー１６が、カーカスプライ１４の折り返し部分１４ｒのタイヤ幅方向外側に位置しており、外側ビードフィラー１６のタイヤ径方向外側端１６ｕは、折り返し部分１４ｒのタイヤ径方向外側端１４ｒｕよりもタイヤ径方向外側に位置している。更に、ゴムチェーファー１８が外側ビードフィラー１６のタイヤ幅方向外側に位置し、リムフランジＲＦと外側ビードフィラー１６とに接している。これにより、外側ビードフィラー１６のタイヤ径方向外側端１６ｕがゴムチェーファー１８でタイヤ外側から覆われており、しかも外側ビードフィラー１６がリムフランジＲＦに接しない構造になっている。 The outer bead filler 16 is positioned on the outer side in the tire width direction of the folded portion 14r of the carcass ply 14, and the tire radial direction outer end 16u of the outer bead filler 16 is more than the tire radial direction outer end 14ru of the folded portion 14r. Is also located on the outer side in the tire radial direction. Further, the rubber chafer 18 is positioned on the outer side in the tire width direction of the outer bead filler 16 and is in contact with the rim flange RF and the outer bead filler 16. Thereby, the outer end 16u of the outer bead filler 16 in the tire radial direction is covered with the rubber chafer 18 from the outer side of the tire, and the outer bead filler 16 is not in contact with the rim flange RF.
　そして、リムフランジＲＦとの離反点Ｋよりもタイヤ径方向外側ではゴムチェーファー１８の厚みが漸減しているので、特にサイドウォール部２４からビード部２６にかけて剛性段差を軽減できるという効果が得られる。 And since the thickness of the rubber chafer 18 is gradually reduced on the outer side in the tire radial direction from the separation point K with respect to the rim flange RF, an effect that the rigidity step can be particularly reduced from the sidewall portion 24 to the bead portion 26 is obtained. .
　また、サイドウォール部２４のタイヤ径方向内側の端部は、ゴムチェーファー１８のタイヤ外側に位置しており、ゴムチェーファー１８のタイヤ径方向外側の部分をサイドウォール部２４が覆う構造になっている。 Further, the end portion of the sidewall portion 24 on the inner side in the tire radial direction is located outside the tire of the rubber chafer 18, and the sidewall portion 24 covers the portion of the rubber chafer 18 on the outer side in the tire radial direction. ing.
　また、従来ではカーカスプライの内側に配置していたフリッパーを、本実施形態の重荷重用タイヤ１０では設けない構成にすることができる（図１参照）。 In addition, it is possible to employ a configuration in which the flipper that has been conventionally arranged inside the carcass ply is not provided in the heavy duty tire 10 of the present embodiment (see FIG. 1).
　［第２実施形態］
　次に、図３を参照して、本発明の第２実施形態に係る重荷重用タイヤを説明する。図３は、本発明の第２実施形態に係る重荷重用タイヤにおけるビード部を示すタイヤ径方向断面図である。 [Second Embodiment]
Next, a heavy duty tire according to a second embodiment of the present invention will be described with reference to FIG. FIG. 3 is a tire radial direction cross-sectional view showing a bead portion in a heavy duty tire according to a second embodiment of the present invention.
　本実施形態では、第１実施形態と異なり、内側ビードフィラー１６ｓが配置されており、カーカスプライ１４が、内側ビードフィラー１６ｓとビードコア１２とを包み込むようにタイヤ幅方向外側へ折り返されている。カーカスプライ１４の折り返し部分１４ｒのうち、タイヤ径方向外側に位置し、所定の長さを有する一端部は、カーカスプライ本体１４ｍに沿って配置され、カーカスプライ１４の折り返し部分１４ｒのうち、一端部を除く残りの部分が内側ビードフィラー１６ｓと外側ビードフィラー１６ｔによって挟まれている。 In this embodiment, unlike the first embodiment, an inner bead filler 16s is arranged, and the carcass ply 14 is folded outward in the tire width direction so as to wrap the inner bead filler 16s and the bead core 12. One end portion of the folded portion 14r of the carcass ply 14 that is located on the outer side in the tire radial direction and has a predetermined length is disposed along the carcass ply main body 14m, and one end portion of the folded portion 14r of the carcass ply 14 is disposed. The remaining part except for is sandwiched between the inner bead filler 16s and the outer bead filler 16t.
　内側ビードフィラー１６ｓが、カーカスプライ１４の折り返し部分１４ｒのタイヤ幅方向内側に位置しており、内側ビードフィラー１６ｓは、カーカスプライ本体１４ｍとカーカスプライ１４の折り返し部分１４ｒによって挟まれて位置している。また、外側ビードフィラー１６ｔが、カーカスプライ１４の折り返し部分１４ｒのタイヤ幅方向外側に位置している。 The inner bead filler 16s is positioned on the inner side in the tire width direction of the folded portion 14r of the carcass ply 14, and the inner bead filler 16s is positioned between the carcass ply main body 14m and the folded portion 14r of the carcass ply 14. . Further, the outer bead filler 16t is located on the outer side in the tire width direction of the folded portion 14r of the carcass ply 14.
　外側ビードフィラー１６ｔのタイヤ径方向外側端１６ｕは、折り返し部分１４ｒのタイヤ径方向外側端１４ｒｕよりもタイヤ径方向外側に位置している。 The outer end 16u in the tire radial direction of the outer bead filler 16t is located on the outer side in the tire radial direction from the outer end 14ru in the tire radial direction of the folded portion 14r.
　内側ビードフィラー１６ｓのタイヤ径方向外側端１６ｓｕは、カーカスプライ１４の折り返し部分１４ｒのタイヤ径方向外側端１４ｒｕよりもタイヤ径方向内側に位置している。また、ビードコアのタイヤ径方向外側端から内側ビードフィラー１６ｓのタイヤ径方向外側端までの、タイヤ径方向に沿った長さを、内側ビードフィラー１６ｓの高さｈｓｂと定義すると（図３参照）、内側ビードフィラー１６ｓの高さｈｓｂは、１０～２０ｍｍの範囲にある。 The tire radial direction outer end 16su of the inner bead filler 16s is located on the inner side in the tire radial direction of the tire radial direction outer end 14ru of the folded portion 14r of the carcass ply 14. Moreover, when the length along the tire radial direction from the tire radial direction outer end of the bead core to the tire radial direction outer end of the inner bead filler 16s is defined as a height hsb of the inner bead filler 16s (see FIG. 3), The height hsb of the inner bead filler 16s is in the range of 10 to 20 mm.
　上記のように、本実施形態では、内側ビードフィラー１６ｓが配置されている点で、第１実施形態と異なっているが、その他の構成は第１実施形態と同様の構成となっている。 As described above, this embodiment is different from the first embodiment in that the inner bead filler 16s is disposed, but the other configurations are the same as those of the first embodiment.
　本実施形態によれば、内側ビードフィラー１６ｓのタイヤ径方向外側端１６ｓｕは、カーカスプライ１４の折り返し部分１４ｒのタイヤ径方向外側端１４ｒｕよりもタイヤ径方向内側に位置しているため、カーカスプライ１４の折り返し部分１４ｒのうち、タイヤ径方向外側に位置する一端部の所定の長さを確保することができる。その結果、カーカスプライ本体１４ｍと折り返し部分１４ｒの一端部との間に、所定の長さを有する薄厚ゴム部分ＧＴを形成することができる。よって第１実施形態と同様に、荷重直下に位置するビード部２６で、折り返し部分１４ｒには、カーカスプライ本体１４ｍに沿って相対移動する力が作用し、薄厚ゴム部分ＧＴには、カーカスプライ本体１４ｍ側に接する側面部ＧＴｍと折り返し部分１４ｒ側に接する側面部ＧＴｒとで互いに逆向きの力が作用する。 According to the present embodiment, the outer end 16su in the tire radial direction of the inner bead filler 16s is located on the inner side in the tire radial direction with respect to the outer end 14ru in the tire radial direction of the folded portion 14r of the carcass ply 14. A predetermined length of one end portion of the folded portion 14r located on the outer side in the tire radial direction can be ensured. As a result, a thin rubber portion GT having a predetermined length can be formed between the carcass ply main body 14m and one end of the folded portion 14r. Therefore, as in the first embodiment, in the bead portion 26 located immediately below the load, a force of relative movement along the carcass ply main body 14m acts on the folded portion 14r, and the carcass ply main body acts on the thin rubber portion GT. Forces in opposite directions act on the side surface portion GTm in contact with the 14m side and the side surface portion GTr in contact with the folded portion 14r side.
　なお、内側ビードフィラー１６ｓの高さｈｓｂ（図３参照）は、１０～２０ｍｍの範囲にあることが好ましい。また、折り返し部分１４ｒの折り返し高さｈｒ（プライ折り返し高さ。図１、図２（ａ）参照）を２３～４０ｍｍとすることが好ましい。このような構成により、カーカスプライ１４の折り返し部分１４ｒのうち、タイヤ径方向外側に位置する一端部の所定の長さを確保できる。 The height hsb (see FIG. 3) of the inner bead filler 16s is preferably in the range of 10 to 20 mm. The folding height hr (ply folding height; see FIGS. 1 and 2A) of the folded portion 14r is preferably 23 to 40 mm. With such a configuration, it is possible to ensure a predetermined length of one end portion located on the outer side in the tire radial direction of the folded portion 14r of the carcass ply 14.
　［第３実施形態］
　本実施形態では、前述の複数の実施形態で示す構成において、カーカスプライ１４のコードの強度を５．０ｃＮ／ｄｔｅｘ以上、かつ、トリート強度が３．３ｋＮ／ｃｍ以上にした実施形態である。本実施形態によれば、カーカスプライ１４の強度を充分に高くすることができる。 [Third Embodiment]
The present embodiment is an embodiment in which the cord strength of the carcass ply 14 is 5.0 cN / dtex or more and the treat strength is 3.3 kN / cm or more in the configuration shown in the above-described plurality of embodiments. According to the present embodiment, the strength of the carcass ply 14 can be sufficiently increased.
　［第４実施形態］
　本実施形態では、前述の複数の実施形態で示す構成において、折り返し部分１４ｒの折り返し高さｈｒ（プライ折り返し高さ。図１、図２（ａ）参照）を２３～４０ｍｍの範囲とした実施形態である。折り返し高さｈｒを２３～４０ｍｍの範囲とすることにより、折り返し部分１４ｒのタイヤ径方向外側端１４ｒｕ（プライ端）での損傷の発生を効果的に防止することができる。 [Fourth Embodiment]
In the present embodiment, in the configuration shown in the above-described plurality of embodiments, the folding height hr (ply folding height; see FIGS. 1 and 2A) of the folding portion 14r is in the range of 23 to 40 mm. It is. By setting the folding height hr in the range of 23 to 40 mm, it is possible to effectively prevent the occurrence of damage at the outer end 14ru (ply end) in the tire radial direction of the folded portion 14r.
　ここで、カーカスプライ１４の折り返し部分１４ｒの折り返し高さｈｒとは、以下のように規定される。すなわち、図１や図２（ａ）に示すように、タイヤ径方向断面において、ビードコア１２の断面中心Ｃを通過し、水平方向Ｘおよび垂直方向Ｙの何れにも４５°の角度θをなしてタイヤ外側でかつタイヤ中心軸側に向かう直線を基準直線Ｓとした場合に、この基準直線Ｓと折り返し部分１４ｒとの交点Ｐから折り返し部分１４ｒのタイヤ径方向外側端１４ｒｕまでのタイヤ径方向距離が折り返し高さｈｒとなる。 Here, the folded height hr of the folded portion 14r of the carcass ply 14 is defined as follows. That is, as shown in FIG. 1 and FIG. 2A, in the tire radial direction cross section, it passes through the cross-sectional center C of the bead core 12 and forms an angle θ of 45 ° in both the horizontal direction X and the vertical direction Y. When a straight line toward the tire center axis side on the tire outer side is defined as a reference straight line S, a tire radial direction distance from an intersection P between the reference straight line S and the folded portion 14r to a tire radial outer end 14ru of the folded portion 14r is The folding height is hr.
　また、上記の折り返し高さｈｒは、重荷重用タイヤ１０に正規リムを取り付け、正規内圧をかけた状態での高さである。 The folded height hr is a height when a normal rim is attached to the heavy load tire 10 and a normal internal pressure is applied.
　ここで、「正規リム」とは、タイヤのサイズに応じて下記の規格に規定された標準リムをいい、「正規内圧」とは、下記の規格に記載されている、適用サイズにおける単輪の最大負荷能力に対応する空気圧をいい、「正規荷重」とは、下記の規格の適用サイズにおける単輪の最大荷重（最大負荷能力）をいうものとする。そして規格とは、タイヤが生産または使用される地域に有効な産業規格であって、たとえば、日本では「日本自動車タイヤ協会」の“ＪＡＴＭＡ　ＹＥＡＲ　ＢＯＯＫ”であり、アメリカ合衆国では“ＴＨＥ　ＴＩＲＥ　ＡＮＤ　ＲＩＭ　ＡＳＳＯＣＩＡＴＩＯＮ　ＩＮＣ．”の“ＹＥＡＲ　ＢＯＯＫ”であり、欧州では、“Ｔｈｅ　Ｅｕｒｏｐｅａｎ　Ｔｙｒｅ　ａｎｄ　Ｒｉｍ　Ｔｅｃｈｎｉｃａｌ　Ｏｒｇａｎｉｓａｔｉｏｎ”の“ＳＴＡＮＤＡＲＤ　ＭＡＮＵＡＬ”である。なお、本明細書では、これ以降の記載などでもこれらを考慮して記載されている。 Here, “regular rim” refers to the standard rim specified in the following standards according to the tire size, and “regular internal pressure” refers to the single wheel at the applicable size described in the following standards. The air pressure corresponding to the maximum load capacity is referred to, and the “normal load” refers to the maximum load (maximum load capacity) of a single wheel in the applicable size of the following standard. The standard is an industrial standard that is effective in the area where tires are produced or used. For example, in Japan, it is “JATMA YEAR BOOK” of the “Japan Automobile Tire Association”, and in the United States “THE TIRE AND RIM ASSOCATION INC” “YEAR BOOK” in Europe, and “STANDARD MANUAL” in “The European Tire and Rim Technical Organization” in Europe. In addition, in this specification, it describes in consideration of these also in subsequent description.
　［第５実施形態］
　本実施形態では、前述の複数の実施形態で示す構成において、外側ビードフィラー１６の高さｈｂ（図１参照）を２５～４０ｍｍの範囲とした実施形態である。高さｈｂを２５～４０ｍｍの範囲とすることにより、ビード部２６の耐久性を充分に確保し易い構成にすることができる。 [Fifth Embodiment]
The present embodiment is an embodiment in which the height hb (see FIG. 1) of the outer bead filler 16 is in the range of 25 to 40 mm in the configuration shown in the plurality of embodiments described above. By setting the height hb in the range of 25 to 40 mm, it is possible to make it easy to ensure the durability of the bead portion 26 sufficiently.
　ここで、外側ビードフィラー１６の高さｈｂとは、外側ビードフィラー１６のタイヤ径方向内側端１６ｂからタイヤ径方向外側端１６ｕまでのタイヤ径方向距離のことである。 Here, the height hb of the outer bead filler 16 refers to the distance in the tire radial direction from the tire radial inner end 16b of the outer bead filler 16 to the tire radial outer end 16u.
　［第６実施形態］
　本実施形態では、前述の複数の実施形態で示す構成において、図１に示すように、ゴムチェーファー１８のタイヤ径方向外側端１８ｕを、外側ビードフィラー１６のタイヤ径方向外側端１６ｕよりも高さｈｇだけタイヤ径方向外側に配置させた実施形態である。ここで高さｈｇは０～１５ｍｍの範囲、好ましくは５～１５ｍｍの範囲とされる。本実施形態によれば、ビード部２６の強度を保ちつつ、外側ビードフィラー１６のタイヤ径方向外側端１６ｕからの損傷の発生を効果的に防止することができる。 [Sixth Embodiment]
In the present embodiment, in the configuration shown in the plurality of embodiments described above, as shown in FIG. 1, the tire radial outer end 18 u of the rubber chafer 18 is higher than the tire radial outer end 16 u of the outer bead filler 16. This is an embodiment in which the distance hg is arranged on the outer side in the tire radial direction. Here, the height hg is in the range of 0 to 15 mm, preferably in the range of 5 to 15 mm. According to the present embodiment, it is possible to effectively prevent the outer bead filler 16 from being damaged from the tire radial direction outer end 16u while maintaining the strength of the bead portion 26.
　［実験例］
　本発明者は、重荷重用タイヤ１０として、折り返し高さｈｂを１８ｍｍ、２８ｍｍ、３８ｍｍとした３種類のタイヤを製造し、各タイヤについて、同一走行条件でのプライ端セパメジャー、平均歪、および、振幅歪を測定した。測定結果を図４に示す。 [Experimental example]
The inventor manufactured three types of tires having a turnback height hb of 18 mm, 28 mm, and 38 mm as the heavy load tire 10, and for each tire, a ply end separation measure under the same traveling condition, an average strain, and Amplitude distortion was measured. The measurement results are shown in FIG.
　ここで、プライ端セパメジャーの値は小さいほど良い評価となる。また、タイヤに生じる歪の評価は、平均歪と振幅歪とを乗算などして両者を考慮した値にして評価するものであり、値が小さいほど良い評価となる。 Here, the smaller the value of the ply end separate measure, the better the evaluation. In addition, the evaluation of the strain generated in the tire is performed by multiplying the average strain and the amplitude strain and taking into consideration both, and the smaller the value, the better the evaluation.
　図４から判るように、折り返し高さｈｂが３８ｍｍのタイヤでは振幅歪が比較的大きく、折り返し高さｈｂが１８ｍｍのタイヤでは平均歪が比較的大きい。そして、タイヤに生じる歪に関しては、折り返し高さｈｂが２８ｍｍのタイヤが最も良いという評価になった。 As can be seen from FIG. 4, the tire having a turnback height hb of 38 mm has a relatively large amplitude distortion, and the tire having a turnback height hb of 18 mm has a relatively large average distortion. Regarding the distortion generated in the tire, the evaluation was that the tire with the folding height hb of 28 mm was the best.
　また、プライ端セパメジャーでは折り返し高さｈｂが２８ｍｍのタイヤが最も良い評価となり、歪に関する評価結果と合致した。 Also, in the ply end separate measure, the tire with the folding height hb of 28 mm was the best evaluation, which was consistent with the evaluation result regarding strain.
　本実験例により、カーカスプライ１４の折り返し部分１４ｒの折り返し高さｈｂは、２３～４０ｍｍの範囲が好ましいと考えられる。 According to this experimental example, it is considered that the folding height hb of the folded portion 14r of the carcass ply 14 is preferably in the range of 23 to 40 mm.
　［解析計算例］
　本発明者は、図５に示すように、従来の小型トラック用の重荷重用タイヤの一例（以下、従来例という）、第１実施形態の一例（以下、実施例という）、および、第１実施形態に比べ、カーカスプライ４４の内側（カーカスプライ本体とカーカスプライの折り返し部分との間）に内側ビードフィラー４６を配置した重荷重用タイヤの一例（以下、比較例という）について、解析計算により、プライ端セパメジャーの値を算出した。解析条件および解析結果を図５に併せて示す。 [Analysis calculation example]
As shown in FIG. 5, the inventor has an example of a conventional heavy duty tire for a light truck (hereinafter referred to as a conventional example), an example of a first embodiment (hereinafter referred to as an example), and a first implementation. Compared to the configuration, an example of a heavy duty tire (hereinafter referred to as a comparative example) in which the inner bead filler 46 is disposed inside the carcass ply 44 (between the carcass ply main body and the folded portion of the carcass ply) is referred to as a ply by analytical calculation. The value of the edge sepa measure was calculated. The analysis conditions and analysis results are also shown in FIG.
　ここで、従来例では２枚のカーカスプライ８４ａ、８４ｂを配置して、タイヤ内側のカーカスプライ８４ａの折り返し部分８４ｒの端部（プライ端）をタイヤ外側のカーカスプライ８４ｂで覆う構造である。また、実施例では、従来例のカーカスプライ８４ａ、８４ｂのプライ強力を１００とした場合、カーカスプライ１４のプライ強力が１８０であり、カーカスプライ８４ａ、８４ｂの２倍近い高強力のものを想定している。比較例のカーカスプライ４４もプライ強力が１８０のものを想定している。 Here, in the conventional example, two carcass plies 84a and 84b are arranged, and the end portion (ply end) of the folded portion 84r of the carcass ply 84a inside the tire is covered with the carcass ply 84b outside the tire. Further, in the embodiment, assuming that the ply strength of the carcass plies 84a and 84b of the conventional example is 100, the ply strength of the carcass ply 14 is 180, and the strength of the carcass plies 84a and 84b is almost twice as high. ing. The carcass ply 44 of the comparative example is also assumed to have a ply strength of 180.
　また、従来例、実施例、比較例とも、ビードコアがスチールコードで構成される例を想定している。 Also, in the conventional example, the example, and the comparative example, an example in which the bead core is formed of a steel cord is assumed.
　また、図５では、ドットハッチの領域、斜線ハッチの領域、網状ハッチの領域、の順に、発生している歪が順次大きくなっていることを示している。 Further, FIG. 5 shows that the generated distortion is sequentially increased in the order of the dot hatch area, the hatched hatch area, and the mesh hatch area.
　プライ強力１００のカーカスプライ８４ａ、８４ｂを２枚配置した従来例では、プライ端セパメジャーは０．０２となっていた。プライ強力１８０のカーカスプライ４４を１枚配置した比較例では、プライ端セパメジャーは０．１２となっていた。プライ強力１８０のカーカスプライ１４を１枚配置した実施例では、プライ端セパメジャーは０．０４となっていた。 In the conventional example in which two carcass plies 84a and 84b having a ply strength of 100 are arranged, the ply end sepa major is 0.02. In the comparative example in which one carcass ply 44 having a ply strength of 180 is arranged, the ply end separator major is 0.12. In an example in which one carcass ply 14 having a ply strength 180 is disposed, the ply end sepa major is 0.04.
　実施例では、カーカスプライ１４をスチールコードで構成されるビードコア１２を包み込むようにタイヤ幅方向外側へ折り返し、折り返し部分１４ｒをカーカスプライ本体１４ｍに沿って配置し、しかも、外側ビードフィラー１６を折り返し部分１４ｒのタイヤ幅方向外側に配置している。このように、カーカスプライとして１枚の高強力のカーカスプライ１４を配置する構造としても、プライ端セパメジャーを従来例に比べてさほど上げず（悪化させず）に済むという結果になった。 In the embodiment, the carcass ply 14 is folded outward in the tire width direction so as to wrap the bead core 12 made of a steel cord, the folded portion 14r is disposed along the carcass ply body 14m, and the outer bead filler 16 is folded. 14r is arranged outside in the tire width direction. As described above, the structure in which one high-strength carcass ply 14 is disposed as the carcass ply results in that the ply end separator measure does not need to be raised (deteriorated) much compared to the conventional example.
　以上の本発明の実施形態は、本発明の理解を容易にするために記載された単なる例示に過ぎず、本発明は当該実施形態に限定されるものではない。本発明の技術的範囲は、上記実施形態で開示した具体的な技術事項に限らず、そこから容易に導きうる様々な変形、変更、代替技術なども含むものである。 The embodiment of the present invention described above is merely an example described for facilitating understanding of the present invention, and the present invention is not limited to the embodiment. The technical scope of the present invention is not limited to the specific technical matters disclosed in the above embodiment, but includes various modifications, changes, alternative techniques, and the like that can be easily derived therefrom.
　本出願は、２０１４年６月４日に出願された日本国特許願第２０１４－１１５４２５に基づく優先権を主張しており、この出願の全内容が参照により本明細書に組み込まれる。 This application claims priority based on Japanese Patent Application No. 2014-115425 filed on June 4, 2014, the entire contents of which are incorporated herein by reference.
　本発明によれば、１枚のカーカスプライを配置する簡素な構造にしても、内圧保持性能とビード部耐久性能とが確保された重荷重用タイヤを提供することができる。 According to the present invention, even with a simple structure in which one carcass ply is arranged, it is possible to provide a heavy-duty tire in which internal pressure holding performance and bead portion durability performance are ensured.
１０…重荷重用タイヤ、１２…ビードコア、１４…カーカスプライ、１４ｍ…カーカスプライ本体、１４ｒ…折り返し部分、１４ｒｕ…タイヤ径方向外側端、１６，１６ｔ…外側ビードフィラー、１６ｓ…内側ビードフィラー、１６ｕ…タイヤ径方向外側端、１８…ゴムチェーファー、１８ｕ…タイヤ径方向外側端、２４…サイドウォール部、ｈｂ…高さ、ｈｒ…折り返し高さ、ＲＦ…リムフランジ
 
  DESCRIPTION OF SYMBOLS 10 ... Heavy load tire, 12 ... Bead core, 14 ... Carcass ply, 14m ... Carcass ply main body, 14r ... Turn-up part, 14ru ... Tire radial direction outer end, 16, 16t ... Outer bead filler, 16s ... Inner bead filler, 16u ... Tire radial outer end, 18 ... rubber chafer, 18u ... tire radial outer end, 24 ... sidewall, hb ... height, hr ... folding height, RF ... rim flange

Claims (5)

  1. 　カーカスプライのコードは、５１００～９０００ｄｔｅｘの範囲の繊度を有し、かつ、２ｃＮ／ｄｔｅｘ荷重時の伸びが３．６～５．６％となる範囲の剛性を有し、
    　前記カーカスプライはスチールコードで構成されるビードコアを包み込むようにタイヤ幅方向外側へ折り返され、前記カーカスプライの折り返し部分がカーカスプライ本体に沿って配置され、
    　前記折り返し部分のタイヤ幅方向外側に位置する外側ビードフィラーの、タイヤ径方向外側端は、前記折り返し部分のタイヤ径方向外側端よりもタイヤ径方向外側に位置し、
    　ゴムチェーファーが、前記外側ビードフィラーのタイヤ幅方向外側に位置してリムフランジと前記外側ビードフィラーとに接し、前記ゴムチェーファーと前記リムフランジとの離反点よりもタイヤ径方向外側において、前記ゴムチェーファーの厚みが漸減しており、
    　サイドウォール部が、前記ゴムチェーファーに接しつつ前記カーカスプライ本体に沿って配置されていること
    　を特徴とする重荷重用タイヤ。     The carcass ply cord has a fineness in the range of 5100 to 9000 dtex, and has a rigidity in a range of 3.6 to 5.6% in elongation at a load of 2 cN / dtex,
    The carcass ply is folded outward in the tire width direction so as to wrap a bead core composed of a steel cord, and the folded portion of the carcass ply is disposed along the carcass ply body.
    The outer end in the tire radial direction of the outer bead filler located on the outer side in the tire width direction of the folded portion is located on the outer side in the tire radial direction from the outer end in the tire radial direction of the folded portion,
    A rubber chafer is located on the outer side in the tire width direction of the outer bead filler and is in contact with the rim flange and the outer bead filler, on the outer side in the tire radial direction from the separation point between the rubber chafer and the rim flange, The thickness of the rubber chafer is gradually decreasing,
    A heavy-duty tire characterized in that a sidewall portion is disposed along the carcass ply main body in contact with the rubber chafer.
  2. 　請求項１に記載の重荷重用タイヤであって、
    　前記カーカスプライのコードは、強度が５．０ｃＮ／ｄｔｅｘ以上、トリート強度が３．３ｋＮ／ｃｍ以上であること
    　を特徴とする重荷重用タイヤ。     The heavy duty tire according to claim 1,
    The heavy duty tire characterized in that the carcass ply cord has a strength of 5.0 cN / dtex or more and a treat strength of 3.3 kN / cm or more.
  3. 　請求項１又は２に記載の重荷重用タイヤであって、
    　前記カーカスプライの前記折り返し部分の折り返し高さが２３～４０ｍｍの範囲であること
    　を特徴とする重荷重用タイヤ。     The heavy duty tire according to claim 1 or 2,
    A heavy duty tire characterized in that the folded height of the folded portion of the carcass ply is in the range of 23 to 40 mm.
  4. 　請求項１乃至３のいずれか一項に記載の重荷重用タイヤであって、
    　前記外側ビードフィラーの高さが２５～４０ｍｍの範囲であること
    　を特徴とする重荷重用タイヤ。     The heavy duty tire according to any one of claims 1 to 3,
    The heavy duty tire, wherein the height of the outer bead filler is in the range of 25 to 40 mm.
  5. 　請求項１乃至４のいずれか一項に記載の重荷重用タイヤであって、
    　前記ゴムチェーファーのタイヤ径方向外側端が前記外側ビードフィラーのタイヤ径方向外側端よりも０～１５ｍｍの範囲でタイヤ径方向外側に位置していること
    　を特徴とする重荷重用タイヤ。
          The heavy duty tire according to any one of claims 1 to 4,
    A heavy duty tire characterized in that the outer end in the tire radial direction of the rubber chafer is located on the outer side in the tire radial direction within a range of 0 to 15 mm from the outer end in the tire radial direction of the outer bead filler.
PCT/JP2015/065753 2014-06-04 2015-06-01 Heavy duty tire WO2015186654A1 (en)

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Cited By (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US20170072750A1 (en) * 2014-02-26 2017-03-16 Sumitomo Rubber Industries, Ltd. Pneumatic tire
US11453249B2 (en) * 2018-10-22 2022-09-27 Sumitomo Rubber Industries, Ltd. Tire

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JPS6357305A (en) * 1986-08-28 1988-03-12 Bridgestone Corp Heavy duty pneumatic radial tire having carcass ply made of aromatic polyamide fiber cord
JPH0899502A (en) * 1994-09-30 1996-04-16 Bridgestone Corp Pneumatic radial tire for heavy load
JP2002283814A (en) * 2001-03-26 2002-10-03 Sumitomo Rubber Ind Ltd Pneumatic tire
JP2013001196A (en) * 2011-06-14 2013-01-07 Bridgestone Corp Pneumatic tire

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JPS6357305A (en) * 1986-08-28 1988-03-12 Bridgestone Corp Heavy duty pneumatic radial tire having carcass ply made of aromatic polyamide fiber cord
JPH0899502A (en) * 1994-09-30 1996-04-16 Bridgestone Corp Pneumatic radial tire for heavy load
JP2002283814A (en) * 2001-03-26 2002-10-03 Sumitomo Rubber Ind Ltd Pneumatic tire
JP2013001196A (en) * 2011-06-14 2013-01-07 Bridgestone Corp Pneumatic tire

Cited By (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US20170072750A1 (en) * 2014-02-26 2017-03-16 Sumitomo Rubber Industries, Ltd. Pneumatic tire
US10513154B2 (en) * 2014-02-26 2019-12-24 Sumitomo Rubber Industries, Ltd. Pneumatic tire with specified bead portions
US11453249B2 (en) * 2018-10-22 2022-09-27 Sumitomo Rubber Industries, Ltd. Tire

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