WO2012161314A1 - Tire - Google Patents

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Publication number
WO2012161314A1
WO2012161314A1 PCT/JP2012/063490 JP2012063490W WO2012161314A1 WO 2012161314 A1 WO2012161314 A1 WO 2012161314A1 JP 2012063490 W JP2012063490 W JP 2012063490W WO 2012161314 A1 WO2012161314 A1 WO 2012161314A1
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WO
WIPO (PCT)
Prior art keywords
tire
rubber layer
groove
gauge thickness
width
Prior art date
Application number
PCT/JP2012/063490
Other languages
French (fr)
Japanese (ja)
Inventor
充幸 和氣
Original Assignee
株式会社ブリヂストン
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Filing date
Publication date
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 WO2012161314A1 publication Critical patent/WO2012161314A1/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
    • B60C11/00—Tyre tread bands; Tread patterns; Anti-skid inserts
    • B60C11/0041—Tyre tread bands; Tread patterns; Anti-skid inserts comprising different tread rubber layers
    • B60C11/005—Tyre tread bands; Tread patterns; Anti-skid inserts comprising different tread rubber layers with cap and base layers
    • B60C11/0058—Tyre tread bands; Tread patterns; Anti-skid inserts comprising different tread rubber layers with cap and base layers with different cap rubber layers in the axial direction
    • 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
    • B60C11/00—Tyre tread bands; Tread patterns; Anti-skid inserts
    • B60C11/03—Tread patterns
    • B60C11/0306—Patterns comprising block rows or discontinuous ribs
    • 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
    • B60C11/00—Tyre tread bands; Tread patterns; Anti-skid inserts
    • B60C11/03—Tread patterns
    • B60C2011/0337—Tread patterns characterised by particular design features of the pattern
    • B60C2011/0386—Continuous ribs
    • B60C2011/0388—Continuous ribs provided at the equatorial plane

Definitions

  • the present invention relates to a tire including a pair of bead cores and a carcass layer having a toroidal shape straddling between the pair of bead cores.
  • a pair of bead cores, a carcass layer having a toroidal shape straddling between a pair of bead cores, a belt layer disposed adjacent to the carcass layer, and a bead core, a carcass layer, and a rubber layer covering the belt layer Tires equipped are known.
  • the tire includes a bead portion having a bead core, a tread portion having a road surface contact surface, a sidewall portion forming a side surface of the tire, and a shoulder portion provided between the sidewall portion and the tread portion.
  • Patent Documents 1 and 2 For the purpose of improving the grip performance and the performance on ice, techniques for forming the road surface contact surface of the tread portion with foamed rubber have been proposed (for example, Patent Documents 1 and 2).
  • JP 2004-050963 A Japanese Patent Laid-Open No. 2007-131084
  • an object of the present invention is to provide a tire that can reduce noise while suppressing a decrease in steering stability.
  • the tire according to the first feature includes a pair of bead cores, a carcass layer having a toroidal shape straddling between the pair of bead cores, and a tread portion having a road surface contact surface.
  • the tread portion includes a central portion that forms a predetermined range including the tire equator line in the tire width direction, and an outer portion that is adjacent to the outside of the central portion in the tire width direction.
  • a distance W from the tire equator line to the end of the road surface contact surface in the tire width direction is a width W.
  • the distance from the tire equator line to the end of the central portion in the tire width direction is a width WT.
  • a ratio WT / W of the width WT to the width W is 0.15 or more and 0.6 or less.
  • the central portion does not have a foam rubber layer on the surface of the central portion, and the outer portion has a foam rubber layer on the surface of the outer portion.
  • the gauge thickness of the foamed rubber layer in the tire radial direction is less than 20% of the gauge thickness of the outer portion in the tire radial direction.
  • the gauge thickness of the foamed rubber layer in the tire radial direction is 5% or more and less than 20% of the gauge thickness of the outer portion in the tire radial direction.
  • FIG. 1 is a view showing a tire 100 according to the first embodiment.
  • FIG. 2 is a view showing the tire 100 according to the first embodiment.
  • FIG. 3 is a diagram showing a road surface ground plane according to the first embodiment.
  • FIG. 4 is a view showing a tire 100 according to the first modification.
  • FIG. 5 is a diagram showing the evaluation result 1.
  • FIG. 6 is a diagram showing the evaluation result 2.
  • the tire according to the embodiment includes a pair of bead cores, a carcass layer having a toroidal shape straddling the pair of bead cores, and a tread portion having a road surface.
  • the tread portion includes a central portion that forms a predetermined range including the tire equator line in the tire width direction, and an outer portion that is adjacent to the outside of the central portion in the tire width direction.
  • a distance W from the tire equator line to the end of the road surface contact surface in the tire width direction is a width W.
  • the distance from the tire equator line to the end of the central portion in the tire width direction is a width WT.
  • a ratio WT / W of the width WT to the width W is 0.15 or more and 0.6 or less.
  • the central portion does not have a foam rubber layer on the surface of the central portion, and the outer portion has a foam rubber layer on the surface of the outer portion.
  • the gauge thickness of the foamed rubber layer in the tire radial direction is less than 20% of the gauge thickness of the outer portion in the tire radial direction.
  • the center portion does not have the foam rubber layer on the surface of the center portion, and the outer portion has the foam rubber layer on the surface of the outer portion. Therefore, noise can be reduced while suppressing a decrease in steering stability.
  • the central portion is defined so that the ratio WT / W of the width WT to the width W satisfies a condition larger than 0.1, the central portion having no foamed rubber layer is sufficiently secured. , A decrease in steering stability is suppressed. Further, since the central portion is defined so as to satisfy the condition that the ratio WT / W of the width WT to the width W is 0.6 or less, the outer portion having the foamed rubber layer is sufficiently secured, and the noise reduction effect is achieved. can get.
  • the gauge thickness of the foam rubber layer is less than 20% of the gauge thickness of the outer part. Therefore, a decrease in steering stability is suppressed.
  • a groove in contact with the foam rubber layer is provided on the road surface ground contact surface.
  • the maximum gauge thickness of the foamed rubber layer is less than 33% of the maximum groove depth in the tire radial direction. That is, the value obtained by dividing the gauge thickness of the foam rubber layer by the maximum value of the groove depth in the tire radial direction (gauge thickness of the foam rubber layer / maximum value of the groove depth in the tire radial direction) is less than 33%. is there. Since the volume of the pattern noise has a correlation with the groove volume, the volume of the pattern noise decreases if the groove depth decreases due to tire wear.
  • the foam rubber layer reduces the pattern noise volume with a foam rubber layer, and when the tire with a low pattern noise volume wears, the foam rubber layer decreases or disappears.
  • the decrease in stability can be further suppressed. As a result, it is possible to achieve both suppression of steering stability reduction and noise reduction throughout the tire usage period.
  • FIG.1 and FIG.2 is a figure which shows the tire 100 which concerns on 1st Embodiment.
  • the tire 100 includes a bead portion 10, a sidewall portion 20, a shoulder portion 30, and a tread portion 40.
  • the bead portion 10 is provided on the innermost side in the tire radial direction among the portions constituting the tire 100.
  • the bead portion 10 is continuously provided along the tire circumferential direction.
  • the bead part 10 is a part for fixing the tire 100 to the rim.
  • the bead portion 10 is covered with rubber.
  • the sidewall portion 20 is provided outside the bead portion 10 in the tire radial direction among the portions constituting the tire 100.
  • the sidewall portion 20 is continuously provided along the tire circumferential direction.
  • the sidewall portion 20 constitutes the side surface of the tire 100.
  • the sidewall portion 20 is covered with rubber.
  • the shoulder portion 30 is provided between the sidewall portion 20 and the tread portion 40 among the portions constituting the tire 100.
  • the shoulder portion 30 is continuously provided along the tire circumferential direction.
  • the shoulder portion 30 is covered with rubber.
  • the tread portion 40 is a portion constituting a road surface contact surface that contacts the road surface among the portions constituting the tire 100.
  • the tread portion 40 is continuously provided along the tire circumferential direction.
  • a tread pattern formed by, for example, a groove (circumferential groove) extending along the tire circumferential direction or a (width groove) extending along the tire width direction is provided on the road surface contact surface of the tread portion 40. .
  • the tire 100 includes a bead core 110, a carcass layer 120, and a belt layer 130, as shown in FIGS.
  • the bead core 110 includes a bead core 110 ⁇ / b> A and a bead core 110 ⁇ / b> B, and configures the bead unit 10.
  • the bead core 110 has a ring shape and is configured by a bead wire (not shown).
  • the carcass layer 120 has a toroidal shape straddling between the bead core 110A and the bead core 110B.
  • the carcass layer 120 is composed of, for example, a plurality of carcass cords (not shown) extending along the tire radial direction (or tire width direction).
  • the carcass layer 120 is folded back at the bead core 110 toward the outside in the tire width direction.
  • the belt layer 130 includes a belt layer 130 ⁇ / b> A and a belt layer 130 ⁇ / b> B, and constitutes the tread portion 40.
  • the belt layer 130 is disposed on the outer side in the tire radial direction with respect to the carcass layer 120.
  • the belt layer 130 has a configuration in which a belt cord is covered with rubber.
  • the belt cord provided in the belt layer 130A may intersect with the belt cord provided in the belt layer 130B.
  • the tread portion 40 includes a central portion 41A constituting a predetermined range including the tire equator line in the tire width direction, and an outer portion 41B (outer portion 41B 1) adjacent to the outside of the central portion 41A in the tire width direction. And an outer portion 41B 2 ).
  • the central portion 41A does not have a foam rubber layer on the surface (road surface grounding surface) of the central portion 41A.
  • the outer portion 41B has a foam rubber layer 42 on the surface (road surface ground surface) of the outer portion 41B.
  • the foamed rubber layer 42 is made of a rubber material having bubbles.
  • the foaming rate of the foamed rubber layer 42 is less than 40%.
  • the foaming rate is the ratio of the volume of bubbles to the volume other than bubbles in a unit volume.
  • the gauge thickness 42g of the foamed rubber layer 42 in the tire radial direction is less than 20% of the gauge thickness 41Bg of the outer portion 41B in the tire radial direction. As a result, a decrease in steering stability associated with the arrangement of the foam rubber layer 42 is suppressed.
  • the gauge thickness 41Bg of the outer portion 41B is the maximum gauge thickness from the tread surface (road surface contact surface) to the belt layer 130B located on the outermost side in the tire radial direction.
  • the gauge thickness 42g of the foamed rubber layer 42 is preferably 5% or more of the gauge thickness 41Bg of the outer portion 41B. Thereby, the noise reduction effect accompanying the arrangement of the foamed rubber layer 42 is sufficiently obtained.
  • the gauge thickness 42g of the foamed rubber layer 42 is the gauge thickness 42g of the foamed rubber layer 42 at the position where the gauge thickness 41Bg of the outer part 41B is maximum in the outer part 41B. Therefore, the gauge thickness 42g of the foam rubber layer 42 and the gauge thickness 41Bg of the outer portion 41B are measured at the same position.
  • FIG. 3 is a diagram showing a road surface ground plane according to the first embodiment.
  • the road surface ground surface is provided with a circumferential main groove 43, a circumferential sub groove 44, a width direction groove 45, a lug groove 46, and the like.
  • the circumferential main groove 43 is a groove extending along the tire circumferential direction.
  • the circumferential main groove 43 is arranged on the inner side in the tire width direction than the circumferential sub groove 44.
  • the circumferential sub-groove 44 is a groove extending along the tire circumferential direction.
  • the circumferential sub-groove 44 is disposed outside the circumferential main groove 43 in the tire width direction.
  • the width direction groove 45 is a groove extending along the tire width direction.
  • the width direction groove 45 communicates with the circumferential main groove 43 and the circumferential sub groove 44.
  • the lug groove 46 is a groove extending along the tire width direction. Here, the lug groove 46 communicates with the circumferential sub-groove 44.
  • the circumferential main groove 43, the circumferential sub groove 44, the width groove 45, and the lug groove 46 are in contact with the foamed rubber layer 42.
  • the road surface contact surface is a surface in contact with the road surface of the tire 100 under normal conditions.
  • the road surface contact surface is a surface in contact with the road surface among the surfaces of the tire 100.
  • the road surface contact surface may be constituted by the shoulder portion 30 in addition to the tread portion 40.
  • the normal load and the normal internal pressure are values determined by standard organizations such as JATMA, ETRTO, and TRA.
  • the normal environmental conditions are an atmospheric pressure of 1 atm and an air temperature of 20 ° C.
  • the distance (width) from the tire equator line CL to the end of the road surface contact surface in the tire width direction is represented by “W”.
  • the distance (width) from the tire equator line CL to the end of the central portion 41A in the tire width direction is “WT”.
  • the ratio WT / W of the width WT to the width W is 0.15 or more and 0.6 or less. That is, the central portion 41A is defined so that the condition that the ratio WT / W is 0.15 or more is satisfied. Similarly, the central portion 41A is defined so that the condition that the ratio WT / W is 0.6 or less is satisfied.
  • the central portion 41A is defined so that the condition that the ratio WT / W is 0.15 or more is satisfied, the central portion 41A that does not have the foamed rubber layer 42 is sufficiently secured, and steering stability is improved. The decline in sex is suppressed. Since the central portion 41A is defined so that the condition where the ratio WT / W is smaller is satisfied, the outer portion 41B having the foamed rubber layer 42 is sufficiently secured, and a noise reduction effect is obtained.
  • the groove having the maximum groove depth in the tire radial direction (for example, A value obtained by dividing the maximum value of the gauge thickness of the foamed rubber layer by the maximum value of the circumferential main groove 43) (for example, the gauge thickness of the foamed rubber layer 42 / the maximum value of the depth of the circumferential main groove 43) is 33. It is preferable that it is less than%.
  • the maximum value of the gauge thickness of the foamed rubber layer 42 / the groove depth of the lug groove 46 is preferably less than 33%.
  • the noise reduction effect does not increase significantly. For this reason, by setting the maximum value of the gauge thickness of the foam rubber layer to less than 33% of the maximum value of the groove depth in the tire radial direction, the volume of pattern noise is reduced by the foam rubber layer when new.
  • the steering stability can be improved by eliminating the foamed rubber layer 42 at the time of wear of the tire in which the volume of the pattern noise is reduced by reducing the volume of the groove.
  • the central portion 41A does not have the foam rubber layer 42 on the surface of the central portion 41A, and the outer portion 41B has the foam rubber layer 42 on the surface of the outer portion 41B. Therefore, noise can be reduced while suppressing a decrease in steering stability.
  • the foam rubber layer 42 is provided on the surface of the outer portion 41B.
  • the foamed rubber layer 42 is not only on the surface of the outer portion 41B, but also on the groove bottoms of the circumferential main grooves 43 and the circumferential sub grooves 44 described above. Provided.
  • the foamed rubber layer 42 may be provided on the groove walls of the circumferential main groove 43 and the circumferential subgroove 44 described above.
  • the foamed rubber layer 42 may be provided on the bottoms of the width direction grooves 45 and the lug grooves 46 described above in addition to the surface of the outer portion 41B.
  • the foamed rubber layer 42 may be provided on the groove walls of the width direction groove 45 and the lug groove 46 described above.
  • evaluation results of the tire according to the embodiment will be described. Specifically, the tires were mounted on the vehicle in accordance with the following conditions, the vehicle running test was performed, and the tire characteristics were evaluated.
  • the actual measured noise value was evaluated under the following common conditions.
  • the steering stability was evaluated subjectively in the range of -5 to +5 under the following common conditions.
  • the tire according to the conventional example was evaluated with reference (0).
  • Tire size 195 / 65R15
  • the tires according to the conventional example, the comparative example 1, the comparative example 2, and the examples 1 to 3 are provided with the circumferential main grooves extending in the tire circumferential direction on the road surface contact surface. Except for the tire according to the conventional example, the circumferential main groove is adjacent to the foamed rubber layer. In any tire, the maximum depth of the circumferential main groove in the tire radial direction is 6.8 mm. However, as shown in FIG. 5, the ratio of the maximum gauge thickness of the foam rubber layer and the maximum depth of the circumferential main groove (foam rubber layer gauge thickness / maximum groove depth) is different.
  • the tire according to the conventional example is a tire having no foamed rubber layer.
  • the tires according to Comparative Example 1, Comparative Example 2, and Examples 1 to 3 are tires having a foamed rubber layer on the surface of the outer portion.
  • the ratio of the gauge thickness of the foam rubber layer to the gauge thickness of the outer portion is different.
  • the tires according to Comparative Example 1, Comparative Example 2, and Example 1 are tires having a foamed rubber layer at the groove bottom of the groove provided on the road surface ground surface.
  • Comparative Example 1 Comparative Example 2, Comparative Example 2, and Examples 1 to 3, it should be noted that W is 72 mm, WT is 32 mm, and the ratio WT / W is the same value. is there.
  • Comparative Example 1 Comparative Example 2, and Examples 1 to 3 a noise reduction effect was obtained by providing a foamed rubber layer on the surface of the outer portion.
  • Examples 1 to 3 have a sufficient noise reduction effect.
  • the gauge thickness ratio is preferably 5% or more.
  • the tires according to Comparative Example 3, Comparative Example 4, Example 1, Example 4, and Example 5 are tires having a foam rubber layer on the surface of the outer portion.
  • Comparative Example 3 Comparative Example 4, Example 1, Example 4, and Example 5, the gauge thickness ratio is a similar value.
  • Example 3 As shown in FIG. 6, in Comparative Example 3, the noise reduction effect was not obtained because the ratio WT / W was larger than 0.6. In Comparative Example 4, since the ratio WT / W was smaller than 0.15, the steering stability was lowered. On the other hand, in Example 1, Example 4, and Example 5, since the ratio WT / W is 0.15 or more and 0.6 or less, a noise reduction effect is achieved while suppressing a decrease in steering stability. Obtained.

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

Abstract

A tire (100) is provided with: a pair of bead cores (110); a carcass layer (120) that is toroidally-shaped and spans between the pair of bead cores (110); and a tread part (40) that has a road contacting surface. The tread part (40) includes a center section (41A) that does not include a foam rubber layer (42), and an exterior section (41B) that includes the foam rubber layer (42). The ratio (WT/W) of a width (WT), which extends from a tire equator line (CL) to the end of the center section (41A), to a width (W), which extends from the tire equator line (CL) to the end of the road contacting surface is not less than 0.15 and not greater than 0.6. The gauge thickness of the foam rubber layer (42) is less than 20% of the gauge thickness of the exterior section (41B).

Description

タイヤtire
　本発明は、１対のビードコアと、１対のビードコア間に跨るトロイダル形状を有するカーカス層とを備えるタイヤに関する。 The present invention relates to a tire including a pair of bead cores and a carcass layer having a toroidal shape straddling between the pair of bead cores.
　従来、１対のビードコアと、１対のビードコア間に跨るトロイダル形状を有するカーカス層と、カーカス層に隣接して配置されるベルト層と、ビードコア、カーカス層及びベルト層を被覆するゴム層とを備えるタイヤが知られている。 Conventionally, a pair of bead cores, a carcass layer having a toroidal shape straddling between a pair of bead cores, a belt layer disposed adjacent to the carcass layer, and a bead core, a carcass layer, and a rubber layer covering the belt layer Tires equipped are known.
　タイヤは、ビードコアを有するビード部と、路面接地面を有するトレッド部と、タイヤの側面を形成するサイドウォール部と、サイドウォール部とトレッド部との間に跨って設けられるショルダー部とを備える。 The tire includes a bead portion having a bead core, a tread portion having a road surface contact surface, a sidewall portion forming a side surface of the tire, and a shoulder portion provided between the sidewall portion and the tread portion.
　ここで、タイヤの回転に伴って、タイヤと路面との相互作用によって騒音が発生することが知られている。このような騒音を低減する技術として、トレッド部の路面接地面を発泡ゴムによって構成する技術が知られている。 Here, it is known that noise is generated by the interaction between the tire and the road surface as the tire rotates. As a technique for reducing such noise, a technique is known in which the road surface contact surface of the tread portion is made of foamed rubber.
　なお、グリップ性能や氷上性能を高めることを目的として、トレッド部の路面接地面を発泡ゴムによって構成する技術が提案されている（例えば、特許文献１、２）。 For the purpose of improving the grip performance and the performance on ice, techniques for forming the road surface contact surface of the tread portion with foamed rubber have been proposed (for example, Patent Documents 1 and 2).
特開２００４－０５０９６３号公報JP 2004-050963 A 特開２００７－１３１０８４号公報Japanese Patent Laid-Open No. 2007-131084
　しかしながら、発泡ゴムの剛性は一般的に低い。上述した技術では、トレッド部の路面接地面の全体が発泡ゴムによって構成されているため、操縦安定性が低下してしまう。 However, the rigidity of foamed rubber is generally low. In the above-described technique, since the entire road surface contact surface of the tread portion is made of foamed rubber, steering stability is lowered.
　そこで、本発明は、上述した課題を解決するためになされたものであり、操縦安定性の低下を抑制しながら、騒音を低減することを可能とするタイヤを提供することを目的とする。 Therefore, the present invention has been made to solve the above-described problems, and an object of the present invention is to provide a tire that can reduce noise while suppressing a decrease in steering stability.
　第１の特徴に係るタイヤは、１対のビードコアと、前記１対のビードコア間に跨るトロイダル形状を有するカーカス層と、路面接地面を有するトレッド部とを備える。前記トレッド部は、タイヤ幅方向においてタイヤ赤道線を含む所定範囲を構成する中心部分と、前記タイヤ幅方向において前記中心部分の外側に隣接する外側部分とを有する。前記タイヤ幅方向において前記タイヤ赤道線から前記路面接地面の端までの距離が幅Ｗである。前記タイヤ幅方向において前記タイヤ赤道線から前記中心部分の端までの距離が幅ＷＴである。前記幅ＷＴと前記幅Ｗとの比率ＷＴ／Ｗは、０．１５以上、かつ、０．６以下である。前記中心部分は、前記中心部分の表面に発泡ゴム層を有しておらず、前記外側部分は、前記外側部分の表面に発泡ゴム層を有している。タイヤ径方向における前記発泡ゴム層のゲージ厚は、前記タイヤ径方向における前記外側部分のゲージ厚の２０％未満である。 The tire according to the first feature includes a pair of bead cores, a carcass layer having a toroidal shape straddling between the pair of bead cores, and a tread portion having a road surface contact surface. The tread portion includes a central portion that forms a predetermined range including the tire equator line in the tire width direction, and an outer portion that is adjacent to the outside of the central portion in the tire width direction. A distance W from the tire equator line to the end of the road surface contact surface in the tire width direction is a width W. The distance from the tire equator line to the end of the central portion in the tire width direction is a width WT. A ratio WT / W of the width WT to the width W is 0.15 or more and 0.6 or less. The central portion does not have a foam rubber layer on the surface of the central portion, and the outer portion has a foam rubber layer on the surface of the outer portion. The gauge thickness of the foamed rubber layer in the tire radial direction is less than 20% of the gauge thickness of the outer portion in the tire radial direction.
　第１の特徴において、前記タイヤ径方向における前記発泡ゴム層のゲージ厚は、前記タイヤ径方向における前記外側部分のゲージ厚の５％以上、かつ、２０％未満である。 In the first feature, the gauge thickness of the foamed rubber layer in the tire radial direction is 5% or more and less than 20% of the gauge thickness of the outer portion in the tire radial direction.
図１は、第１実施形態に係るタイヤ１００を示す図である。FIG. 1 is a view showing a tire 100 according to the first embodiment. 図２は、第１実施形態に係るタイヤ１００を示す図である。FIG. 2 is a view showing the tire 100 according to the first embodiment. 図３は、第１実施形態に係る路面接地面を示す図である。FIG. 3 is a diagram showing a road surface ground plane according to the first embodiment. 図４は、変更例１に係るタイヤ１００を示す図である。FIG. 4 is a view showing a tire 100 according to the first modification. 図５は、評価結果１を示す図である。FIG. 5 is a diagram showing the evaluation result 1. 図６は、評価結果２を示す図である。FIG. 6 is a diagram showing the evaluation result 2.
　以下において、本発明の実施形態に係るタイヤについて、図面を参照しながら説明する。なお、以下の図面の記載において、同一又は類似の部分には、同一又は類似の符号を付している。 Hereinafter, a tire according to an embodiment of the present invention will be described with reference to the drawings. In the following description of the drawings, the same or similar parts are denoted by the same or similar reference numerals.
　ただし、図面は模式的なものであり、各寸法の比率などは現実のものとは異なることに留意すべきである。従って、具体的な寸法などは以下の説明を参酌して判断すべきである。また、図面相互間においても互いの寸法の関係や比率が異なる部分が含まれていることは勿論である。 However, it should be noted that the drawings are schematic and ratios of dimensions are different from actual ones. Therefore, specific dimensions and the like should be determined in consideration of the following description. Moreover, it is a matter of course that portions having different dimensional relationships and ratios are included between the drawings.
　［実施形態の概要］
　実施形態に係るタイヤは、１対のビードコアと、前記１対のビードコア間に跨るトロイダル形状を有するカーカス層と、路面接地面を有するトレッド部とを備える。前記トレッド部は、タイヤ幅方向においてタイヤ赤道線を含む所定範囲を構成する中心部分と、前記タイヤ幅方向において前記中心部分の外側に隣接する外側部分とを有する。前記タイヤ幅方向において前記タイヤ赤道線から前記路面接地面の端までの距離が幅Ｗである。前記タイヤ幅方向において前記タイヤ赤道線から前記中心部分の端までの距離が幅ＷＴである。前記幅ＷＴと前記幅Ｗとの比率ＷＴ／Ｗは、０．１５以上、かつ、０．６以下である。前記中心部分は、前記中心部分の表面に発泡ゴム層を有しておらず、前記外側部分は、前記外側部分の表面に発泡ゴム層を有している。タイヤ径方向における前記発泡ゴム層のゲージ厚は、前記タイヤ径方向における前記外側部分のゲージ厚の２０％未満である。 [Outline of Embodiment]
The tire according to the embodiment includes a pair of bead cores, a carcass layer having a toroidal shape straddling the pair of bead cores, and a tread portion having a road surface. The tread portion includes a central portion that forms a predetermined range including the tire equator line in the tire width direction, and an outer portion that is adjacent to the outside of the central portion in the tire width direction. A distance W from the tire equator line to the end of the road surface contact surface in the tire width direction is a width W. The distance from the tire equator line to the end of the central portion in the tire width direction is a width WT. A ratio WT / W of the width WT to the width W is 0.15 or more and 0.6 or less. The central portion does not have a foam rubber layer on the surface of the central portion, and the outer portion has a foam rubber layer on the surface of the outer portion. The gauge thickness of the foamed rubber layer in the tire radial direction is less than 20% of the gauge thickness of the outer portion in the tire radial direction.
　実施形態では、中心部分は、中心部分の表面に発泡ゴム層を有しておらず、外側部分は、外側部分の表面に発泡ゴム層を有している。従って、操縦安定性の低下を抑制しながら、騒音を低減することができる。 In the embodiment, the center portion does not have the foam rubber layer on the surface of the center portion, and the outer portion has the foam rubber layer on the surface of the outer portion. Therefore, noise can be reduced while suppressing a decrease in steering stability.
　詳細には、幅ＷＴと幅Ｗとの比率ＷＴ／Ｗが０．１よりも大きい条件を満たすように中心部分が定義されるため、発泡ゴム層を有していない中心部分が十分に確保され、操縦安定性の低下が抑制される。また、幅ＷＴと幅Ｗとの比率ＷＴ／Ｗが０．６以下である条件を満たすように中心部分が定義されるため、発泡ゴム層を有する外側部分が十分に確保され、騒音低減効果が得られる。 Specifically, since the central portion is defined so that the ratio WT / W of the width WT to the width W satisfies a condition larger than 0.1, the central portion having no foamed rubber layer is sufficiently secured. , A decrease in steering stability is suppressed. Further, since the central portion is defined so as to satisfy the condition that the ratio WT / W of the width WT to the width W is 0.6 or less, the outer portion having the foamed rubber layer is sufficiently secured, and the noise reduction effect is achieved. can get.
　また、発泡ゴム層のゲージ厚が外側部分のゲージ厚の２０％未満である。従って、操縦安定性の低下が抑制される。 Also, the gauge thickness of the foam rubber layer is less than 20% of the gauge thickness of the outer part. Therefore, a decrease in steering stability is suppressed.
　また、路面接地面には、発泡ゴム層に接する溝が設けられる。発泡ゴム層のゲージ厚の最大値は、タイヤ径方向における溝の深さの最大値の３３％未満である。すなわち、発泡ゴム層のゲージ厚をタイヤ径方向における溝の深さの最大値で割った値（発泡ゴム層のゲージ厚／タイヤ径方向における溝の深さの最大値）が、３３％未満である。パターンノイズの音量は、溝の容積に相関があるため、タイヤの摩耗により溝の深さが減少すれば、パターンノイズの音量は小さくなる。従って、パターンノイズの音量が大きいタイヤの新品時には、発泡ゴム層によって、パターンノイズの音量の低減を図りつつ、パターンノイズの音量が小さいタイヤの摩耗時には、発泡ゴム層が減少又は消失するため、操縦安定性の低下をさらに抑制できる。その結果、タイヤの使用期間全体を通じて、操縦安定性の低下の抑制と、騒音の低減との両立が可能となる。 Also, a groove in contact with the foam rubber layer is provided on the road surface ground contact surface. The maximum gauge thickness of the foamed rubber layer is less than 33% of the maximum groove depth in the tire radial direction. That is, the value obtained by dividing the gauge thickness of the foam rubber layer by the maximum value of the groove depth in the tire radial direction (gauge thickness of the foam rubber layer / maximum value of the groove depth in the tire radial direction) is less than 33%. is there. Since the volume of the pattern noise has a correlation with the groove volume, the volume of the pattern noise decreases if the groove depth decreases due to tire wear. Therefore, when a tire with a high pattern noise volume is new, the foam rubber layer reduces the pattern noise volume with a foam rubber layer, and when the tire with a low pattern noise volume wears, the foam rubber layer decreases or disappears. The decrease in stability can be further suppressed. As a result, it is possible to achieve both suppression of steering stability reduction and noise reduction throughout the tire usage period.
　［第１実施形態］
　（タイヤの構成）
　以下において、第１実施形態に係るタイヤの構成について説明する。図１及び図２は、第１実施形態に係るタイヤ１００を示す図である。 [First Embodiment]
(Tire composition)
Below, the composition of the tire concerning a 1st embodiment is explained. FIG.1 and FIG.2 is a figure which shows the tire 100 which concerns on 1st Embodiment.
　第１に、タイヤ１００は、図１に示すように、ビード部１０と、サイドウォール部２０と、ショルダー部３０と、トレッド部４０とを有する。 First, as shown in FIG. 1, the tire 100 includes a bead portion 10, a sidewall portion 20, a shoulder portion 30, and a tread portion 40.
　ビード部１０は、タイヤ１００を構成する部位のうち、タイヤ径方向において、最も内側に設けられる。ビード部１０は、タイヤ周方向に沿って連続的に設けられる。ビード部１０は、タイヤ１００をリムに固定するための部位である。なお、ビード部１０は、ゴムによって被覆されている。 The bead portion 10 is provided on the innermost side in the tire radial direction among the portions constituting the tire 100. The bead portion 10 is continuously provided along the tire circumferential direction. The bead part 10 is a part for fixing the tire 100 to the rim. The bead portion 10 is covered with rubber.
　サイドウォール部２０は、タイヤ１００を構成する部位のうち、タイヤ径方向において、ビード部１０よりも外側に設けられる。サイドウォール部２０は、タイヤ周方向に沿って連続的に設けられる。サイドウォール部２０は、タイヤ１００の側面を構成する。なお、サイドウォール部２０は、ゴムによって被覆されている。 The sidewall portion 20 is provided outside the bead portion 10 in the tire radial direction among the portions constituting the tire 100. The sidewall portion 20 is continuously provided along the tire circumferential direction. The sidewall portion 20 constitutes the side surface of the tire 100. The sidewall portion 20 is covered with rubber.
　ショルダー部３０は、タイヤ１００を構成する部位のうち、サイドウォール部２０とトレッド部４０との間に跨って設けられる。ショルダー部３０は、タイヤ周方向に沿って連続的に設けられる。なお、ショルダー部３０は、ゴムによって被覆されている。 The shoulder portion 30 is provided between the sidewall portion 20 and the tread portion 40 among the portions constituting the tire 100. The shoulder portion 30 is continuously provided along the tire circumferential direction. The shoulder portion 30 is covered with rubber.
　トレッド部４０は、タイヤ１００を構成する部位のうち、路面に接地する路面接地面を構成する部位である。トレッド部４０は、タイヤ周方向に沿って連続的に設けられる。トレッド部４０の路面接地面には、例えば、タイヤ周方向に沿って延びる溝（周方向溝）やタイヤ幅方向に沿って延びる（幅方向溝）などによって形成されるトレッドパターンが設けられている。 The tread portion 40 is a portion constituting a road surface contact surface that contacts the road surface among the portions constituting the tire 100. The tread portion 40 is continuously provided along the tire circumferential direction. A tread pattern formed by, for example, a groove (circumferential groove) extending along the tire circumferential direction or a (width groove) extending along the tire width direction is provided on the road surface contact surface of the tread portion 40. .
　第２に、タイヤ１００は、図１及び図２に示すように、ビードコア１１０と、カーカス層１２０と、ベルト層１３０とを有する。 Second, the tire 100 includes a bead core 110, a carcass layer 120, and a belt layer 130, as shown in FIGS.
　ビードコア１１０は、ビードコア１１０Ａ及びビードコア１１０Ｂを有しており、ビード部１０を構成する。ビードコア１１０は、リング状形状を有しており、ビードワイヤー（不図示）によって構成される。 The bead core 110 includes a bead core 110 </ b> A and a bead core 110 </ b> B, and configures the bead unit 10. The bead core 110 has a ring shape and is configured by a bead wire (not shown).
　カーカス層１２０は、ビードコア１１０Ａとビードコア１１０Ｂとの間に跨るトロイダル形状を有する。カーカス層１２０は、例えば、タイヤ径方向（或いは、タイヤ幅方向）に沿って延びる複数のカーカスコード（不図示）によって構成される。カーカス層１２０は、ビードコア１１０でタイヤ幅方向の外側に向けて折り返されている。 The carcass layer 120 has a toroidal shape straddling between the bead core 110A and the bead core 110B. The carcass layer 120 is composed of, for example, a plurality of carcass cords (not shown) extending along the tire radial direction (or tire width direction). The carcass layer 120 is folded back at the bead core 110 toward the outside in the tire width direction.
　ベルト層１３０は、ベルト層１３０Ａ及びベルト層１３０Ｂを有しており、トレッド部４０を構成する。ベルト層１３０は、カーカス層１２０に対して、タイヤ径方向の外側に配置される。ベルト層１３０は、ベルトコードがゴムで被覆された構成を有する。ベルト層１３０Ａに設けられるベルトコードは、ベルト層１３０Ｂに設けられるベルトコードと交錯していてもよい。 The belt layer 130 includes a belt layer 130 </ b> A and a belt layer 130 </ b> B, and constitutes the tread portion 40. The belt layer 130 is disposed on the outer side in the tire radial direction with respect to the carcass layer 120. The belt layer 130 has a configuration in which a belt cord is covered with rubber. The belt cord provided in the belt layer 130A may intersect with the belt cord provided in the belt layer 130B.
　第１実施形態では、トレッド部４０は、タイヤ幅方向においてタイヤ赤道線を含む所定範囲を構成する中心部分４１Ａと、タイヤ幅方向において中心部分４１Ａの外側に隣接する外側部分４１Ｂ（外側部分４１Ｂ１及び外側部分４１Ｂ２）とを有する。 In the first embodiment, the tread portion 40 includes a central portion 41A constituting a predetermined range including the tire equator line in the tire width direction, and an outer portion 41B (outer portion 41B 1) adjacent to the outside of the central portion 41A in the tire width direction. And an outer portion 41B 2 ).
　中心部分４１Ａは、中心部分４１Ａの表面（路面接地面）に発泡ゴム層を有していない。これに対して、外側部分４１Ｂは、外側部分４１Ｂの表面（路面接地面）に発泡ゴム層４２を有している。 The central portion 41A does not have a foam rubber layer on the surface (road surface grounding surface) of the central portion 41A. In contrast, the outer portion 41B has a foam rubber layer 42 on the surface (road surface ground surface) of the outer portion 41B.
　なお、発泡ゴム層４２は、気泡を有するゴム材料によって構成される。発泡ゴム層４２の発泡率は、４０％未満である。なお、発泡率は、単位体積において、気泡の体積と気泡以外の体積との比である。 The foamed rubber layer 42 is made of a rubber material having bubbles. The foaming rate of the foamed rubber layer 42 is less than 40%. The foaming rate is the ratio of the volume of bubbles to the volume other than bubbles in a unit volume.
　タイヤ径方向における発泡ゴム層４２のゲージ厚４２ｇは、タイヤ径方向における外側部分４１Ｂのゲージ厚４１Ｂｇの２０％未満である。これによって、発泡ゴム層４２の配置に伴う操縦安定性の低下が抑制される。ここで、外側部分４１Ｂのゲージ厚４１Ｂｇは、トレッド踏面（路面接地面）から、タイヤ径方向において最も外側に位置するベルト層１３０Ｂまでの最大となるゲージ厚である。 The gauge thickness 42g of the foamed rubber layer 42 in the tire radial direction is less than 20% of the gauge thickness 41Bg of the outer portion 41B in the tire radial direction. As a result, a decrease in steering stability associated with the arrangement of the foam rubber layer 42 is suppressed. Here, the gauge thickness 41Bg of the outer portion 41B is the maximum gauge thickness from the tread surface (road surface contact surface) to the belt layer 130B located on the outermost side in the tire radial direction.
　発泡ゴム層４２のゲージ厚４２ｇは、外側部分４１Ｂのゲージ厚４１Ｂｇの５％以上であることが好ましい。これによって、発泡ゴム層４２の配置に伴う騒音低減効果が十分に得られる。 The gauge thickness 42g of the foamed rubber layer 42 is preferably 5% or more of the gauge thickness 41Bg of the outer portion 41B. Thereby, the noise reduction effect accompanying the arrangement of the foamed rubber layer 42 is sufficiently obtained.
　ここで、発泡ゴム層４２のゲージ厚４２ｇは、外側部分４１Ｂにおいて、外側部分４１Ｂのゲージ厚４１Ｂｇが最大となる位置における発泡ゴム層４２のゲージ厚４２ｇである。従って、発泡ゴム層４２のゲージ厚４２ｇと外側部分４１Ｂのゲージ厚４１Ｂｇは、同一の位置において、測定される。 Here, the gauge thickness 42g of the foamed rubber layer 42 is the gauge thickness 42g of the foamed rubber layer 42 at the position where the gauge thickness 41Bg of the outer part 41B is maximum in the outer part 41B. Therefore, the gauge thickness 42g of the foam rubber layer 42 and the gauge thickness 41Bg of the outer portion 41B are measured at the same position.
　（路面接地面）
　以下において、第１実施形態に係る路面接地面について説明する。図３は、第１実施形態に係る路面接地面を示す図である。 (Road surface contact surface)
In the following, the road surface contact surface according to the first embodiment will be described. FIG. 3 is a diagram showing a road surface ground plane according to the first embodiment.
　図３に示すように、路面接地面には、周方向主溝４３、周方向副溝４４、幅方向溝４５、ラグ溝４６などが設けられている。 As shown in FIG. 3, the road surface ground surface is provided with a circumferential main groove 43, a circumferential sub groove 44, a width direction groove 45, a lug groove 46, and the like.
　周方向主溝４３は、タイヤ周方向に沿って延びる溝である。周方向主溝４３は、周方向副溝４４よりもタイヤ幅方向の内側に配置される。 The circumferential main groove 43 is a groove extending along the tire circumferential direction. The circumferential main groove 43 is arranged on the inner side in the tire width direction than the circumferential sub groove 44.
　周方向副溝４４は、タイヤ周方向に沿って延びる溝である。周方向副溝４４は、周方向主溝４３よりもタイヤ幅方向の外側に配置される。 The circumferential sub-groove 44 is a groove extending along the tire circumferential direction. The circumferential sub-groove 44 is disposed outside the circumferential main groove 43 in the tire width direction.
　幅方向溝４５は、タイヤ幅方向に沿って延びる溝である。ここでは、幅方向溝４５は、周方向主溝４３及び周方向副溝４４に連通する。 The width direction groove 45 is a groove extending along the tire width direction. Here, the width direction groove 45 communicates with the circumferential main groove 43 and the circumferential sub groove 44.
　ラグ溝４６は、タイヤ幅方向に沿って延びる溝である。ここでは、ラグ溝４６は、周方向副溝４４に連通する。 The lug groove 46 is a groove extending along the tire width direction. Here, the lug groove 46 communicates with the circumferential sub-groove 44.
　図２及び図３に示すように、本実施形態において、周方向主溝４３、周方向副溝４４、幅方向溝４５、ラグ溝４６は、発泡ゴム層４２に接する。 2 and 3, in the present embodiment, the circumferential main groove 43, the circumferential sub groove 44, the width groove 45, and the lug groove 46 are in contact with the foamed rubber layer 42.
　ここで、路面接地面は、荷重が正規荷重であり、内圧が正規内圧であり、環境条件が通常環境条件である場合において、通常条件下において、タイヤ１００の表面のうち、路面に接する面を意味する。詳細には、直進走行時において、路面接地面は、タイヤ１００の表面のうち、路面に接する面である。なお、路面接地面は、トレッド部４０に加えて、ショルダー部３０によって構成されてもよい。 Here, when the load is a normal load, the internal pressure is a normal internal pressure, and the environmental condition is a normal environmental condition, the road surface contact surface is a surface in contact with the road surface of the tire 100 under normal conditions. means. Specifically, when traveling straight ahead, the road surface contact surface is a surface in contact with the road surface among the surfaces of the tire 100. The road surface contact surface may be constituted by the shoulder portion 30 in addition to the tread portion 40.
　ここで、正規荷重及び正規内圧は、ＪＡＴＭＡ、ＥＴＲＴＯ、ＴＲＡなどの規格機関によって定められた値である。通常環境条件は、１気圧の大気圧、２０℃の気温である。 Here, the normal load and the normal internal pressure are values determined by standard organizations such as JATMA, ETRTO, and TRA. The normal environmental conditions are an atmospheric pressure of 1 atm and an air temperature of 20 ° C.
　図３に示すように、タイヤ幅方向においてタイヤ赤道線ＣＬから路面接地面の端までの距離（幅）は、“Ｗ”で表されている。タイヤ幅方向においてタイヤ赤道線ＣＬから中心部分４１Ａの端までの距離（幅）は、“ＷＴ”である。 As shown in FIG. 3, the distance (width) from the tire equator line CL to the end of the road surface contact surface in the tire width direction is represented by “W”. The distance (width) from the tire equator line CL to the end of the central portion 41A in the tire width direction is “WT”.
　このようなケースにおいて、幅ＷＴと幅Ｗとの比率ＷＴ／Ｗは、０．１５以上、かつ、０．６以下である。すなわち、比率ＷＴ／Ｗが０．１５以上である条件が満たされるように中心部分４１Ａが定義される。同様に、比率ＷＴ／Ｗが０．６以下である条件が満たされるように中心部分４１Ａが定義される。 In such a case, the ratio WT / W of the width WT to the width W is 0.15 or more and 0.6 or less. That is, the central portion 41A is defined so that the condition that the ratio WT / W is 0.15 or more is satisfied. Similarly, the central portion 41A is defined so that the condition that the ratio WT / W is 0.6 or less is satisfied.
　このように、比率ＷＴ／Ｗが０．１５以上である条件が満たされるように中心部分４１Ａが定義されるため、発泡ゴム層４２を有していない中心部分４１Ａが十分に確保され、操縦安定性の低下が抑制される。比率ＷＴ／Ｗがよりも小さい条件が満たされるように中心部分４１Ａが定義されるため、発泡ゴム層４２を有する外側部分４１Ｂが十分に確保され、騒音低減効果が得られる。 Thus, since the central portion 41A is defined so that the condition that the ratio WT / W is 0.15 or more is satisfied, the central portion 41A that does not have the foamed rubber layer 42 is sufficiently secured, and steering stability is improved. The decline in sex is suppressed. Since the central portion 41A is defined so that the condition where the ratio WT / W is smaller is satisfied, the outer portion 41B having the foamed rubber layer 42 is sufficiently secured, and a noise reduction effect is obtained.
　特に、発泡ゴム層４２に接する溝（周方向主溝４３、周方向副溝４４、幅方向溝４５及びラグ溝４６）のうち、タイヤ径方向における溝の深さが最大となる溝（例えば、周方向主溝４３）の最大値によって発泡ゴム層のゲージ厚の最大値を割った値（例えば、発泡ゴム層４２のゲージ厚／周方向主溝４３の溝の深さの最大値）が３３％未満であることが好ましい。例えば、ラグ溝４６の溝深さが最大となる場合、発泡ゴム層４２のゲージ厚／ラグ溝４６の溝の深さの最大値が３３％未満であることが好ましい。 In particular, of the grooves (circumferential main groove 43, circumferential sub-groove 44, width direction groove 45, and lug groove 46) in contact with the foamed rubber layer 42, the groove having the maximum groove depth in the tire radial direction (for example, A value obtained by dividing the maximum value of the gauge thickness of the foamed rubber layer by the maximum value of the circumferential main groove 43) (for example, the gauge thickness of the foamed rubber layer 42 / the maximum value of the depth of the circumferential main groove 43) is 33. It is preferable that it is less than%. For example, when the groove depth of the lug groove 46 is maximized, the maximum value of the gauge thickness of the foamed rubber layer 42 / the groove depth of the lug groove 46 is preferably less than 33%.
　発泡ゴム層４２のゲージ厚の最大値は、タイヤ径方向における溝の深さの最大値の３３％を超えると、騒音の低減効果は大幅に増加することもない。このため、発泡ゴム層のゲージ厚の最大値は、タイヤ径方向における溝の深さの最大値の３３％未満とすることによって、新品時には、発泡ゴム層によって、パターンノイズの音量の低減を図りつつ、溝の容積が小さくなることによってパターンノイズの音量が小さくなるタイヤの摩耗時において、発泡ゴム層４２がなくなることによって、操縦安定性の向上を図ることができる。 If the maximum value of the gauge thickness of the foamed rubber layer 42 exceeds 33% of the maximum value of the groove depth in the tire radial direction, the noise reduction effect does not increase significantly. For this reason, by setting the maximum value of the gauge thickness of the foam rubber layer to less than 33% of the maximum value of the groove depth in the tire radial direction, the volume of pattern noise is reduced by the foam rubber layer when new. On the other hand, the steering stability can be improved by eliminating the foamed rubber layer 42 at the time of wear of the tire in which the volume of the pattern noise is reduced by reducing the volume of the groove.
　（作用及び効果）
　第１実施形態では、中心部分４１Ａは、中心部分４１Ａの表面に発泡ゴム層４２を有しておらず、外側部分４１Ｂは、外側部分４１Ｂの表面に発泡ゴム層４２を有している。従って、操縦安定性の低下を抑制しながら、騒音を低減することができる。 (Function and effect)
In the first embodiment, the central portion 41A does not have the foam rubber layer 42 on the surface of the central portion 41A, and the outer portion 41B has the foam rubber layer 42 on the surface of the outer portion 41B. Therefore, noise can be reduced while suppressing a decrease in steering stability.
　［変更例１］
　以下において、第１実施形態の変更例１について説明する。以下においては、第１実施形態に対する相違点について説明する。 [Modification 1]
Hereinafter, Modification Example 1 of the first embodiment will be described. In the following, differences from the first embodiment will be described.
　第１実施形態では、発泡ゴム層４２は、外側部分４１Ｂの表面に設けられる。 In the first embodiment, the foam rubber layer 42 is provided on the surface of the outer portion 41B.
　これに対して、変更例１では、図４に示すように、発泡ゴム層４２は、外側部分４１Ｂの表面に加えて、上述した周方向主溝４３及び周方向副溝４４の溝底にも設けられる。なお、発泡ゴム層４２は、上述した周方向主溝４３及び周方向副溝４４の溝壁に設けられていてもよい。 On the other hand, in the modified example 1, as shown in FIG. 4, the foamed rubber layer 42 is not only on the surface of the outer portion 41B, but also on the groove bottoms of the circumferential main grooves 43 and the circumferential sub grooves 44 described above. Provided. The foamed rubber layer 42 may be provided on the groove walls of the circumferential main groove 43 and the circumferential subgroove 44 described above.
　或いは、変更例１では、発泡ゴム層４２は、外側部分４１Ｂの表面に加えて、上述した幅方向溝４５及びラグ溝４６の溝底にも設けられてもよい。なお、発泡ゴム層４２は、上述した幅方向溝４５及びラグ溝４６の溝壁に設けられていてもよい。 Alternatively, in the first modification, the foamed rubber layer 42 may be provided on the bottoms of the width direction grooves 45 and the lug grooves 46 described above in addition to the surface of the outer portion 41B. The foamed rubber layer 42 may be provided on the groove walls of the width direction groove 45 and the lug groove 46 described above.
　［評価結果］
　以下において、実施形態に係るタイヤの評価結果について説明する。詳細には、以下の条件に従って、タイヤを車両に装着して、車両の走行試験を行って、タイヤの特性を評価した。 [Evaluation results]
Hereinafter, evaluation results of the tire according to the embodiment will be described. Specifically, the tires were mounted on the vehicle in accordance with the following conditions, the vehicle running test was performed, and the tire characteristics were evaluated.
　騒音の評価については、以下の共通条件で、騒音の実測値を評価した。また、騒音の評価は、“Ｄｉｒｅｃｔｉｖｅ　２００１／４３／ＥＣ”に従って行った。なお、２０～２０ｋＨｚの周波数の音の総和に基づいて、騒音を評価した。
　（共通条件）
　タイヤのサイズ＝１９５／６５Ｒ１５
　タイヤの内圧＝１８０ｋＰａ
　荷重＝４．４ｋＮ
　車速＝８０ｋｍ／ｈ For the noise evaluation, the actual measured noise value was evaluated under the following common conditions. The noise was evaluated according to “Directive 2001/43 / EC”. Note that the noise was evaluated based on the sum of sounds having a frequency of 20 to 20 kHz.
(Common conditions)
Tire size = 195 / 65R15
Tire internal pressure = 180 kPa
Load = 4.4kN
Vehicle speed = 80km / h
  操縦安定性の評価については、以下の共通条件で、－５～＋５の範囲で主観で評価した。なお、操縦安定性の評価では、従来例に係るタイヤを基準（０）として評価した。
  （共通条件）
　タイヤのサイズ＝１９５／６５Ｒ１５
　タイヤの内圧＝２２０ｋＰａ
　荷重＝前輪４．２ｋＮ、後輪３．５ｋＮ
　車速＝８０ｋｍ／ｈ The steering stability was evaluated subjectively in the range of -5 to +5 under the following common conditions. In the evaluation of steering stability, the tire according to the conventional example was evaluated with reference (0).
(Common conditions)
Tire size = 195 / 65R15
Tire internal pressure = 220 kPa
Load = 4.2kN front wheel, 3.5kN rear wheel
Vehicle speed = 80km / h
  （評価結果１）
　以下において、評価結果１について、図５を参照しながら説明する。従来例、比較例1、比較例２、実施例１～実施例３に係るタイヤは、路面接地面にタイヤ周方向に延びる周方向主溝が設けられている。従来例に係るタイヤを除いて、周方向主溝は、発泡ゴム層に隣接している。いずれのタイヤも、タイヤ径方向における周方向主溝の深さの最大値は、６．８ｍｍである。但し、図５に示すように、発泡ゴム層のゲージ厚の最大値と周方向主溝の深さの最大値との比率（発泡ゴム層ゲージ厚／最大溝深さ）が異なっている。ここで、従来例に係るタイヤは、発泡ゴム層を全く有していないタイヤである。比較例1、比較例２、実施例１～実施例３に係るタイヤは、外側部分の表面に発泡ゴム層を有するタイヤである。但し、図５に示すように、外側部分のゲージ厚に対する発泡ゴム層のゲージ厚の比率（ゲージ厚比率）が異なっている。また、比較例１、比較例２及び実施例１に係るタイヤは、路面接地面に設けられる溝の溝底に発泡ゴム層を有するタイヤである。 (Evaluation result 1)
Hereinafter, the evaluation result 1 will be described with reference to FIG. The tires according to the conventional example, the comparative example 1, the comparative example 2, and the examples 1 to 3 are provided with the circumferential main grooves extending in the tire circumferential direction on the road surface contact surface. Except for the tire according to the conventional example, the circumferential main groove is adjacent to the foamed rubber layer. In any tire, the maximum depth of the circumferential main groove in the tire radial direction is 6.8 mm. However, as shown in FIG. 5, the ratio of the maximum gauge thickness of the foam rubber layer and the maximum depth of the circumferential main groove (foam rubber layer gauge thickness / maximum groove depth) is different. Here, the tire according to the conventional example is a tire having no foamed rubber layer. The tires according to Comparative Example 1, Comparative Example 2, and Examples 1 to 3 are tires having a foamed rubber layer on the surface of the outer portion. However, as shown in FIG. 5, the ratio of the gauge thickness of the foam rubber layer to the gauge thickness of the outer portion (gauge thickness ratio) is different. Further, the tires according to Comparative Example 1, Comparative Example 2, and Example 1 are tires having a foamed rubber layer at the groove bottom of the groove provided on the road surface ground surface.
　なお、比較例1、比較例２、実施例１～実施例３において、Ｗは、７２ｍｍであり、ＷＴは、３２ｍｍであり、比率ＷＴ／Ｗは、同一の値であることに留意すべきである。 In Comparative Example 1, Comparative Example 2, and Examples 1 to 3, it should be noted that W is 72 mm, WT is 32 mm, and the ratio WT / W is the same value. is there.
　図５に示すように、比較例１、２では、ゲージ厚比率が２０％よりも大きいため、操縦安定性が低下した。これに対して、実施例１～実施例３では、ゲージ厚比率が２０％未満であるため、操縦安定性の低下が抑制された。 As shown in FIG. 5, in Comparative Examples 1 and 2, since the gauge thickness ratio was larger than 20%, the steering stability was lowered. On the other hand, in Examples 1 to 3, since the gauge thickness ratio was less than 20%, a decrease in steering stability was suppressed.
　また、比較例１、比較例２、実施例１～実施例３では、外側部分の表面に発泡ゴム層を設けることによって、騒音低減効果が得られた。また、ゲージ厚比率が２０％よりも大きい比較例１、比較例２と比べても、実施例１～実施例３では、十分な騒音低減効果が得られた。 In Comparative Example 1, Comparative Example 2, and Examples 1 to 3, a noise reduction effect was obtained by providing a foamed rubber layer on the surface of the outer portion. In addition, compared with Comparative Example 1 and Comparative Example 2 in which the gauge thickness ratio is greater than 20%, Examples 1 to 3 have a sufficient noise reduction effect.
　また、実施例３に示すように、ゲージ厚比率が５％以上であることが好ましいことにつていても確認された。 Further, as shown in Example 3, it was confirmed that the gauge thickness ratio is preferably 5% or more.
　（評価結果２）
　以下において、評価結果２について、図６を参照しながら説明する。比較例３、比較例４、実施例１、実施例４、実施例５に係るタイヤは、外側部分の表面に発泡ゴム層を有するタイヤである。 (Evaluation result 2)
Hereinafter, the evaluation result 2 will be described with reference to FIG. The tires according to Comparative Example 3, Comparative Example 4, Example 1, Example 4, and Example 5 are tires having a foam rubber layer on the surface of the outer portion.
　なお、比較例３、比較例４、実施例１、実施例４、実施例５において、ゲージ厚比率は、同様の値であることに留意すべきである。 It should be noted that in Comparative Example 3, Comparative Example 4, Example 1, Example 4, and Example 5, the gauge thickness ratio is a similar value.
　図６に示すように、比較例３では、比率ＷＴ／Ｗが０．６よりも大きいため、騒音低減効果が得られなかった。比較例４では、比率ＷＴ／Ｗが０．１５よりも小さいため、操縦安定性が低下した。これに対して、実施例１、実施例４，実施例５では、比率ＷＴ／Ｗが０．１５以上かつ０．６以下であるため、操縦安定性の低下を抑制しながら、騒音低減効果が得られた。 As shown in FIG. 6, in Comparative Example 3, the noise reduction effect was not obtained because the ratio WT / W was larger than 0.6. In Comparative Example 4, since the ratio WT / W was smaller than 0.15, the steering stability was lowered. On the other hand, in Example 1, Example 4, and Example 5, since the ratio WT / W is 0.15 or more and 0.6 or less, a noise reduction effect is achieved while suppressing a decrease in steering stability. Obtained.
　［その他の実施形態］
　本発明は上述した実施形態によって説明したが、この開示の一部をなす論述及び図面は、この発明を限定するものであると理解すべきではない。この開示から当業者には様々な代替実施形態、実施例及び運用技術が明らかとなろう。 [Other Embodiments]
Although the present invention has been described with reference to the above-described embodiments, it should not be understood that the descriptions and drawings constituting a part of this disclosure limit the present invention. From this disclosure, various alternative embodiments, examples and operational techniques will be apparent to those skilled in the art.
　なお、日本国特許出願第２０１１－１１８１６１号（２０１１年５月２６日出願）の全内容が、参照により、本願明細書に組み込まれている。 Note that the entire content of Japanese Patent Application No. 2011-118161 (filed on May 26, 2011) is incorporated herein by reference.
　本発明によれば、操縦安定性の低下を抑制しながら、騒音を低減することを可能とするタイヤを提供することができる。 According to the present invention, it is possible to provide a tire that can reduce noise while suppressing a decrease in steering stability.

Claims (3)

  1. 　１対のビードコアと、前記１対のビードコア間に跨るトロイダル形状を有するカーカス層と、路面接地面を有するトレッド部とを備えるタイヤであって、
    　前記トレッド部は、タイヤ幅方向においてタイヤ赤道線を含む所定範囲を構成する中心部分と、前記タイヤ幅方向において前記中心部分の外側に隣接する外側部分とを有しており、
    　前記タイヤ幅方向において前記タイヤ赤道線から前記路面接地面の端までの距離が幅Ｗであり、
    　前記タイヤ幅方向において前記タイヤ赤道線から前記中心部分の端までの距離が幅ＷＴであり、
    　前記幅ＷＴと前記幅Ｗとの比率ＷＴ／Ｗは、０．１５以上、かつ、０．６以下であり、
    　前記中心部分は、前記中心部分の表面に発泡ゴム層を有しておらず、
    　前記外側部分は、前記外側部分の表面に発泡ゴム層を有しており、
    　タイヤ径方向における前記発泡ゴム層のゲージ厚は、前記タイヤ径方向における前記外側部分のゲージ厚の２０％未満であることを特徴とするタイヤ。     A tire comprising a pair of bead cores, a carcass layer having a toroidal shape straddling the pair of bead cores, and a tread portion having a road surface contact surface,
    The tread portion has a central portion that constitutes a predetermined range including a tire equator line in the tire width direction, and an outer portion that is adjacent to the outside of the central portion in the tire width direction,
    The distance from the tire equator line to the end of the road surface contact surface in the tire width direction is a width W,
    The distance from the tire equator line to the end of the central portion in the tire width direction is a width WT,
    The ratio WT / W between the width WT and the width W is 0.15 or more and 0.6 or less,
    The central portion does not have a foam rubber layer on the surface of the central portion,
    The outer portion has a foam rubber layer on the surface of the outer portion;
    The tire characterized in that the gauge thickness of the foamed rubber layer in the tire radial direction is less than 20% of the gauge thickness of the outer portion in the tire radial direction.
  2. 　前記タイヤ径方向における前記発泡ゴム層のゲージ厚は、前記タイヤ径方向における前記外側部分のゲージ厚の５％以上、かつ、２０％未満であることを特徴とする請求項１に記載のタイヤ。 2. The tire according to claim 1, wherein a gauge thickness of the foamed rubber layer in the tire radial direction is 5% or more and less than 20% of a gauge thickness of the outer portion in the tire radial direction.
  3. 　前記路面接地面には、前記発泡ゴム層に接する溝が設けられ、
    　前記発泡ゴム層のゲージ厚の最大値は、前記タイヤ径方向における前記溝の深さの最大値の３３％未満であることを特徴とする請求項１又は２に記載のタイヤ。     The road surface ground surface is provided with a groove in contact with the foam rubber layer,
    The tire according to claim 1 or 2, wherein the maximum value of the gauge thickness of the foamed rubber layer is less than 33% of the maximum value of the depth of the groove in the tire radial direction.
PCT/JP2012/063490 2011-05-26 2012-05-25 Tire WO2012161314A1 (en)

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Cited By (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
FR3026056A1 (en) * 2014-09-22 2016-03-25 Michelin & Cie TIRE WITH BEARING BAND COMPRISING A GRADIENT OF COMPRESSIBILITY
WO2016046615A1 (en) 2014-09-22 2016-03-31 Compagnie Générale Des Établissements Michelin Tyre comprising a tread having a stiffness gradient
CN108909376A (en) * 2018-06-27 2018-11-30 安徽省中日农业环保科技有限公司 A kind of agricultural equipment antiskid device for tyre
US10603957B2 (en) 2013-05-30 2020-03-31 Compagnie Generale Des Etablissements Michelin High-grip profiled tread skims
EP3838624A1 (en) * 2019-12-19 2021-06-23 Sumitomo Rubber Industries, Ltd. Pneumatic tire

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* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JP2005280511A (en) * 2004-03-30 2005-10-13 Sumitomo Rubber Ind Ltd Pneumatic tire
JP2007131084A (en) * 2005-11-09 2007-05-31 Bridgestone Corp Tire
JP2007176417A (en) * 2005-12-28 2007-07-12 Sumitomo Rubber Ind Ltd Studless tire

Patent Citations (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JP2005280511A (en) * 2004-03-30 2005-10-13 Sumitomo Rubber Ind Ltd Pneumatic tire
JP2007131084A (en) * 2005-11-09 2007-05-31 Bridgestone Corp Tire
JP2007176417A (en) * 2005-12-28 2007-07-12 Sumitomo Rubber Ind Ltd Studless tire

Cited By (6)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US10603957B2 (en) 2013-05-30 2020-03-31 Compagnie Generale Des Etablissements Michelin High-grip profiled tread skims
FR3026056A1 (en) * 2014-09-22 2016-03-25 Michelin & Cie TIRE WITH BEARING BAND COMPRISING A GRADIENT OF COMPRESSIBILITY
WO2016046616A1 (en) 2014-09-22 2016-03-31 Compagnie Generale Des Etablissements Michelin Tyre comprising a tread having a compressibility gradient
WO2016046615A1 (en) 2014-09-22 2016-03-31 Compagnie Générale Des Établissements Michelin Tyre comprising a tread having a stiffness gradient
CN108909376A (en) * 2018-06-27 2018-11-30 安徽省中日农业环保科技有限公司 A kind of agricultural equipment antiskid device for tyre
EP3838624A1 (en) * 2019-12-19 2021-06-23 Sumitomo Rubber Industries, Ltd. Pneumatic tire

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