JP2009269421A

JP2009269421A - Pneumatic tire

Info

Publication number: JP2009269421A
Application number: JP2008119685A
Authority: JP
Inventors: Keisuke Itakura; 圭佑板倉
Original assignee: Bridgestone Corp
Current assignee: Bridgestone Corp
Priority date: 2008-05-01
Filing date: 2008-05-01
Publication date: 2009-11-19

Abstract

<P>PROBLEM TO BE SOLVED: To provide a pneumatic tire capable of ensuring straight-ahead driving performance when a vehicle travels at high speed, and enhancing cornering performance by ensuring a grip when a vehicle turns at high speed. <P>SOLUTION: Shapes of first and second inner blocks 19a, 19b located on the IN side of attachment are formed flat at the center of the tire width direction of a tread 11 of a pneumatic tire 10 with a center circumferential groove 16m formed extending along the tire circumferential direction as a boundary. First and second outer blocks 18a, 18b located on the OUT side of attachment are formed so that sectional heights at ends on the IN side of attachment when viewed in the section of the tire width direction are higher than those at ends on the OUT side of attachment. Furthermore, the straight-ahead driving performance when a vehicle travels at high speed, and the grip when a vehicle turns at high speed can be secured by forming contour shapes of adjacent outer blocks 18a, 18b, 18c into saw-teeth shapes. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

本発明は、空気入りタイヤに関するもので、特に、高速時の直進性能とコーナリング性能に優れた空気入りタイヤに関する。 The present invention relates to a pneumatic tire, and more particularly to a pneumatic tire excellent in straight running performance and cornering performance at high speed.

従来、空気入りラジアルタイヤの操縦安定性能、特に、コーナリング性能を向上させる方法として、タイヤ回転方向を指定した方向性パターンを有するタイヤや左右非対称トレッドパターンを有するタイヤが提案されている（例えば、特許文献１参照）。
一方、コーナリング時においては、タイヤ赤道面よりも外側のブロックが外力によって変形することにより、その一部が接地面から浮き上がりやすくなり、そのため、タイヤの接地面積が減少してグリップが低下することが知られている。そこで、陸部をタイヤ軸方向外側端部で０．０５ｍｍ〜１ｍｍ低く、タイヤ軸方向内側端部で０．０５ｍｍ〜１ｍｍ高い傾斜面を有する形状とすることで、上記接地面積の減少を抑制してグリップを確保する方法が提案されている（例えば、特許文献２参照）。
特開２００６−２９０１９４号公報特開平３−１１２７０２号公報 Conventionally, as a method for improving the steering stability performance of a pneumatic radial tire, in particular, cornering performance, a tire having a directional pattern specifying a tire rotation direction and a tire having a left-right asymmetric tread pattern have been proposed (for example, patents). Reference 1).
On the other hand, during cornering, the outer block of the tire equatorial plane is deformed by external force, so that part of the block tends to lift from the grounding surface, and therefore, the grounding area of the tire is reduced and the grip is lowered. Are known. Therefore, the land area has a shape having an inclined surface that is 0.05 mm to 1 mm lower at the outer end in the tire axial direction and 0.05 mm to 1 mm higher at the inner end in the tire axial direction. A method for securing the grip has been proposed (see, for example, Patent Document 2).
JP 2006-290194 A Japanese Patent Laid-Open No. 3-112702

しかしながら、上記トレッドパターンを方向性パターンや左右非対称トレッドパターンとする方法では、低速時のコーナリング特性は確保されるものの、高速旋回時のように、大きな横力が作用した場合には、接地面積が減少して十分なグリップを得ることが困難であった。
一方、陸部をタイヤ軸方向外側端部に向かって低くなる傾斜面とする方法では、旋回時に内側になる部分では陸部の傾斜が入力に対向する方向と異なるため、特に、高速旋回時においては、十分なグリップ得られないだけでなく、傾斜陸部が全て傾斜面を有することから、高速直進性能が低下してしまうといった問題点があった。 However, in the method in which the tread pattern is a directional pattern or a left-right asymmetric tread pattern, cornering characteristics at low speed are ensured, but when a large lateral force is applied, such as during high-speed turning, the ground contact area is reduced. It was difficult to obtain a sufficient grip by decreasing.
On the other hand, in the method of making the land portion an inclined surface that becomes lower toward the outer end portion in the tire axial direction, the slope of the land portion is different from the direction facing the input in the portion that becomes the inner side during turning, particularly during high-speed turning. In addition to not being able to obtain a sufficient grip, the inclined land portion has an inclined surface, which causes a problem that the straight-ahead performance is degraded.

本発明は、従来の問題点に鑑みてなされたもので、高速走行時における直進性能を確保することができるとともに、高速旋回時のグリップを確保してコーナリング性能を向上させることを目的とする。 The present invention has been made in view of conventional problems, and it is an object of the present invention to ensure straight running performance during high-speed running and to secure a grip during high-speed turning to improve cornering performance.

本願の請求項１に記載の発明は、タイヤのトレッド表面にタイヤ周方向に沿って延びるように形成された複数本の周方向溝と、上記周方向溝により区画された陸部とを備えた空気入りタイヤであって、上記陸部のタイヤ幅方向断面の外輪郭形状が、当該タイヤを車両に装着したときに、上記複数本の周方向溝のうちの特定の周方向溝の車体側とは反対側に位置する外側陸部ではタイヤ幅方向の中央側に位置する当該陸部の端部の断面高さがタイヤ幅方向端部側に位置する当該陸部の端部の断面高さよりも高く形成されており、上記特定の周方向溝の車体側に位置する車体側陸部では断面高さが等しく形成されていることを特徴とするものである。上記断面高さは、図２（ａ）のＨ_a1やＨ_a2などで示される、タイヤ幅方向断面で見たとき、陸部１８が隣接する周方向溝１６の底部１６ｋから当該陸部１８の接地面１８ｒまでの距離を指す。また、同図の符号１６ｐ（１８ｐ）は上記周方向溝１６の溝壁（もしくは、陸部１８の周方向溝側の側面）であり、タイヤ幅方向断面で見たときの上記溝壁１６ｐ（もしくは、陸部１８の周方向溝側の側面）の延長方向と上記底部１６ｋに垂直な方向との成す角度（αまたはβ）は溝壁角度である。
請求項２に記載の発明は、請求項１に記載の空気入りタイヤであって、複数本の周方向溝が、主溝と副溝を備えている場合に、上記特定の周方向溝は主溝であることを特徴とする。なお、主溝とは、周方向に連続した溝のうち、溝幅の最大値をＷとしたときに、溝幅がＷ〜０．３×Ｗの範囲の溝幅を有する周方向溝を指し、副溝とは、その溝幅が０．３×Ｗ未満である周方溝を指す。
請求項３に記載の発明は、請求項１または請求項２に記載の空気入りタイヤであって、上記特定の周方向溝がタイヤ赤道面に位置している周方向溝であることを特徴とする。
請求項４に記載の発明は、請求項１〜請求項３のいずれかに記載の空気入りタイヤであって、上記外側陸部のタイヤ幅方向端部側に位置する当該陸部の端部の断面高さが、当該外側陸部のタイヤ幅方向端部側に隣接する外側陸部の中央側に位置する当該陸部の端部の断面高さよりも低く形成されていることを特徴とする。
請求項５に記載の発明は、請求項４に記載の空気入りタイヤであって、上記外側陸部のタイヤ幅方向の中央側に位置する当該陸部の端部の断面高さとタイヤ幅方向端部側に位置する当該陸部の端部の断面高さとの差が２．０ｍｍ〜２．５ｍｍであることを特徴とする。
請求項６に記載の発明は、請求項１〜請求項５のいずれかに記載の空気入りタイヤであって、上記外側陸部のタイヤ幅方向の中央側に隣接する周方向溝の溝壁角度が、タイヤ幅方向端部側に隣接する周方向溝の溝壁角度よりも２°〜７°大きいことを特徴とする。 The invention according to claim 1 of the present application includes a plurality of circumferential grooves formed on the tire tread surface so as to extend along the tire circumferential direction, and a land portion defined by the circumferential grooves. A pneumatic tire, wherein an outer contour shape of a cross section in the tire width direction of the land portion is the vehicle body side of a specific circumferential groove among the plurality of circumferential grooves when the tire is mounted on a vehicle. In the outer land portion located on the opposite side, the cross-sectional height of the end portion of the land portion located on the center side in the tire width direction is higher than the cross-sectional height of the end portion of the land portion located on the end portion side in the tire width direction. The vehicle body side land portion located on the vehicle body side of the specific circumferential groove is formed to have the same cross-sectional height. The cross-sectional height of the land portion 18 is determined from the bottom portion 16k of the circumferential groove 16 adjacent to the land portion 18 when viewed in a cross section in the tire width direction as indicated by H _a1 and H _{a2 in} FIG. The distance to the ground plane 18r is indicated. Moreover, the code | symbol 16p (18p) of the figure is the groove wall of the said circumferential groove | channel 16 (or the side surface by the side of the circumferential groove of the land part 18), and the said groove wall 16p (when viewed in a tire width direction cross section) Alternatively, the angle (α or β) formed between the extending direction of the land portion 18 on the circumferential groove side and the direction perpendicular to the bottom portion 16k is the groove wall angle.
The invention according to claim 2 is the pneumatic tire according to claim 1, wherein when the plurality of circumferential grooves include a main groove and a sub-groove, the specific circumferential groove is a main tire. It is a groove. The main groove refers to a circumferential groove having a groove width in the range of W to 0.3 × W, where W is the maximum value of the groove width among the grooves continuous in the circumferential direction. The sub-groove refers to a circumferential groove whose groove width is less than 0.3 × W.
Invention of Claim 3 is a pneumatic tire of Claim 1 or Claim 2, Comprising: The said specific circumferential groove | channel is the circumferential groove | channel located in a tire equatorial plane, It is characterized by the above-mentioned. To do.
Invention of Claim 4 is a pneumatic tire in any one of Claims 1-3, Comprising: Of the edge part of the said land part located in the tire width direction edge part side of the said outer land part The cross-sectional height is formed to be lower than the cross-sectional height of the end portion of the land portion located on the center side of the outer land portion adjacent to the end portion side of the outer land portion in the tire width direction.
Invention of Claim 5 is a pneumatic tire of Claim 4, Comprising: The cross-sectional height of the edge part of the said land part located in the center side of the tire width direction of the said outer land part, and a tire width direction end The difference with the cross-sectional height of the edge part of the said land part located in the part side is 2.0 mm-2.5 mm, It is characterized by the above-mentioned.
Invention of Claim 6 is a pneumatic tire in any one of Claims 1-5, Comprising: The groove wall angle of the circumferential direction groove | channel adjacent to the center side of the tire width direction of the said outer land part Is larger by 2 ° to 7 ° than the groove wall angle of the circumferential groove adjacent to the end in the tire width direction.

本発明によれば、複数本の周方向溝により区画された陸部のタイヤ幅方向断面の外輪郭形状を、当該タイヤを車両に装着したときに、上記複数本の周方向溝のうちの特定の周方向溝の車体側とは反対側に位置する外側陸部ではタイヤ幅方向の中央側に位置する当該陸部の端部の断面高さがタイヤ幅方向端部側に位置する当該陸部の端部の断面高さよりも高く形成することにより高速旋回時のような大きな横力が作用した場合でも上記外側陸部がタイヤ幅方向の中央側にシフトして接地面積の減少を抑制してグリップを確保することができるので、コーナリング性能を向上させることができる。また、上記特定の周方向溝の車体側に位置する車体側陸部では断面高さを等しく形成することにより直進走行時の陸部の不要な変形を抑制できるので、直進走行性能を確保することができる。
このとき、複数本の周方向溝が、主溝と副溝を備えている場合に、上記特定の周方向溝を主溝とすることで、上記車体側陸部と上記外側陸部とを確実に分離できるので、直進時の走行安定性を向上させることができる。
また、上記特定の周方向溝をタイヤ赤道面に位置している周方向溝とすれば、装着ＩＮ側の陸部が全て上記車体側陸部となり、装着ＯＵＴ側の陸部が全て上記外側陸部となるので、直進走行性能とコーナリング性能とをともに向上させることができる。
また、上記外側陸部のタイヤ幅方向端部側に位置する当該陸部の端部の断面高さを、当該外側陸部のタイヤ幅方向端部側に隣接する外側陸部の中央側に位置する当該陸部の端部の断面高さよりも低く形成して上記外側陸部をのこぎり状とすれば、大きな横力が作用した場合でも接地面積の減少を確実に抑制することができるので、コーナリング性能を更に向上させることができる。
また、直進走行性能とコーナリング性能とをともに向上させるためには、上記外側陸部のタイヤ幅方向の中央側に位置する当該陸部の端部の断面高さとタイヤ幅方向端部側に位置する当該陸部の端部の断面高さとの差の範囲としては２．０ｍｍ〜２．５ｍｍとすることが好ましく、上記外側陸部のタイヤ幅方向の中央側に隣接する周方向溝の溝壁角度を、タイヤ幅方向端部側に隣接する周方向溝の溝壁角度よりも２°〜７°大きくすることが好ましい。 According to the present invention, when the outer contour shape of the cross section of the tire in the tire width direction defined by the plurality of circumferential grooves is mounted on the vehicle, the identification of the plurality of circumferential grooves is performed. In the outer land portion located on the opposite side to the vehicle body side of the circumferential groove, the land portion where the cross-sectional height of the end portion of the land portion located on the center side in the tire width direction is located on the tire width direction end portion side Even when a large lateral force is applied, such as during high-speed turning, the outer land portion shifts to the center side in the tire width direction and suppresses the reduction of the contact area. Since a grip can be ensured, cornering performance can be improved. In addition, since the vehicle body side land portion located on the vehicle body side of the specific circumferential groove has the same cross-sectional height, unnecessary deformation of the land portion during straight traveling can be suppressed, thus ensuring straight traveling performance. Can do.
At this time, when the plurality of circumferential grooves include a main groove and a sub-groove, the vehicle body side land portion and the outer land portion can be reliably secured by using the specific circumferential groove as the main groove. Therefore, it is possible to improve the running stability when going straight.
Further, if the specific circumferential groove is a circumferential groove located on the tire equatorial plane, all the land portions on the mounting IN side are the vehicle body side land portions, and all the land portions on the mounting OUT side are all the outer land portions. Therefore, both straight running performance and cornering performance can be improved.
Further, the cross-sectional height of the end portion of the land portion located on the tire width direction end portion side of the outer land portion is positioned on the center side of the outer land portion adjacent to the tire width direction end portion side of the outer land portion. If the outer land portion is formed in a saw-like shape so as to be lower than the cross-sectional height of the end portion of the land portion, the reduction of the contact area can be surely suppressed even when a large lateral force is applied. The performance can be further improved.
Further, in order to improve both the straight running performance and the cornering performance, the cross-sectional height of the end portion of the land portion located on the center side in the tire width direction of the outer land portion and the end portion side in the tire width direction are positioned. The range of the difference between the cross-sectional height of the end portion of the land portion is preferably 2.0 mm to 2.5 mm, and the groove wall angle of the circumferential groove adjacent to the center side in the tire width direction of the outer land portion. Is preferably larger by 2 ° to 7 ° than the groove wall angle of the circumferential groove adjacent to the end in the tire width direction.

以下、本発明の最良の形態について、図面に基づき説明する。
図１（ａ），（ｂ）は本発明の最良の形態に係る空気入りタイヤ（以下、タイヤという）１０の構成を示す図で、（ａ）図はタイヤ幅方向の断面図、（ｂ）図はトレッドパターンの展開図である。本例のタイヤ１０は車両に装着するときの向きが予め指定されているＩＮ−ＯＵＴ指定のタイヤで、図の右側が当該タイヤ１０を車両に装着したときに車体側となる装着ＩＮ側、図の左側が当該タイヤ１０を車両に装着したときに車体側とは反対側(反車体側)となる装着ＯＵＴ側である。
各図において、１１はトレッド、１２はサイドウオール部、１３はビード部、１４は上記ビード部１３に配置された１対のビードコア１３Ｃにトロイド状をなして跨るボディプライ、１５は上記ボディプライ１４のタイヤ径方向外側に配置された複数のベルトプライから成るベルト層で、このベルト層１５のタイヤ径方向外側にゴム部材（トレッドゴム）から成るトレッド１１が配置されている。
上記トレッド１１にはタイヤ周方向に沿って延長する複数本の周方向溝１６（１６ｍ，１６ａ〜１６ｄ）と上記周方向溝１６に交差するよう設けられ複数本の横溝１７とが形成されている。１６ｍは、上記トレッド１１のタイヤ幅方向中心(赤道面)に位置して、タイヤ周方向に沿って延長する中央周方向溝、１６ａ，１６ｂは上記中央周方向溝１６ｍの装着ＯＵＴ側に位置して、タイヤ周方向に沿って延長する外側周方向溝、１６ｃ，１６ｄは上記中央周方向溝１６ｍの装着ＩＮ側に位置して、タイヤ周方向に沿って延長する内側周方向溝である。
また、上記周方向溝１６と横溝１７とにより複数のブロック１８（１８ａ〜１８ｃ）及びブロック１９（１９ａ〜１９ｃ）が区画される。１８ａは上記外側周方向溝１６ａと上記外側周方向溝１６ｂとで区画された第１の外側ブロック、１８ｂは上記外側周方向溝１６ｂと上記中央周方向溝１６ｍとで区画された第２の外側ブロック、１８ｃは上記外側周方向溝１６ａよりも装着ＯＵＴ側に位置する外側ショルダーブロックである。また、１９ａは上記中央周方向溝１６ｍと上記内側周方向溝１６ｃとで区画された第１の内側ブロック、１９ｂは上記内側周方向溝１６ｃと上記内側周方向溝１６ｄとで区画された第２の内側ブロック、１９ｃは上記内側周方向溝１６ｄよりも装着ＩＮ側に位置する内側ショルダーブロックである。 Hereinafter, the best mode of the present invention will be described with reference to the drawings.
1A and 1B are views showing the configuration of a pneumatic tire (hereinafter referred to as a tire) 10 according to the best mode of the present invention. FIG. 1A is a sectional view in the tire width direction, and FIG. The figure is a development view of the tread pattern. The tire 10 of this example is an IN-OUT designated tire whose direction when mounted on the vehicle is designated in advance, and the right side of the figure is the mounted IN side that is the vehicle body side when the tire 10 is mounted on the vehicle. The left side is the mounting OUT side which is the side opposite to the vehicle body side (the side opposite to the vehicle body) when the tire 10 is mounted on the vehicle.
In each figure, 11 is a tread, 12 is a side wall portion, 13 is a bead portion, 14 is a body ply straddling a pair of bead cores 13C arranged in the bead portion 13 in a toroid form, and 15 is the body ply 14 A tread 11 made of a rubber member (tread rubber) is arranged on the outer side of the belt layer 15 in the tire radial direction.
The tread 11 is formed with a plurality of circumferential grooves 16 (16m, 16a to 16d) extending along the tire circumferential direction and a plurality of lateral grooves 17 provided so as to intersect the circumferential groove 16. . 16m is a central circumferential groove extending along the tire circumferential direction and is located at the tire width direction center (equatorial plane) of the tread 11, and 16a and 16b are located on the mounting OUT side of the central circumferential groove 16m. The outer circumferential grooves 16c and 16d extending along the tire circumferential direction are inner circumferential grooves extending along the tire circumferential direction, located on the mounting IN side of the central circumferential groove 16m.
The circumferential groove 16 and the lateral groove 17 define a plurality of blocks 18 (18a to 18c) and blocks 19 (19a to 19c). 18a is a first outer block defined by the outer circumferential groove 16a and the outer circumferential groove 16b, and 18b is a second outer block defined by the outer circumferential groove 16b and the central circumferential groove 16m. A block 18c is an outer shoulder block located closer to the mounting OUT side than the outer circumferential groove 16a. 19a is a first inner block defined by the central circumferential groove 16m and the inner circumferential groove 16c, and 19b is a second inner block defined by the inner circumferential groove 16c and the inner circumferential groove 16d. The inner block 19c is an inner shoulder block located closer to the mounting IN side than the inner circumferential groove 16d.

本発明の外側陸部に相当する上記第１及び第２の外側ブロック１８ａ，１８ｂは、図２（ａ）に示すように、タイヤ幅方向断面でみたとき、装着ＩＮ側の端部の断面高さＨ_a1，Ｈ_b1はそれぞれ装着ＯＵＴ側の端部の断面高さＨ_a2，Ｈ_b2よりも高く形成されている。また、上記第２の外側ブロック１８ｂの装着ＯＵＴ側に隣接する周方向溝１６ｍの溝壁角度αが、装着ＩＮ側に隣接する周方向溝１６ｂの溝壁角度βよりも大きく形成されている。なお、上記第１の外側ブロック１８ａについても同様である。
また、上記第２の外側ブロック１８ｂの装着ＯＵＴ側（タイヤ幅方向端部側）の断面高さＨ_b2は、上記第２の外側ブロック１８ｂの装着ＯＵＴ側に位置する上記第１の外側ブロック１８ａの装着ＩＮ側（タイヤ幅方向中央側）の断面高さＨ_a1よりも低く形成されており、上記第１の外側ブロック１８ａの装着ＯＵＴ側の断面高さＨ_a2は、上記第１の外側ブロック１８ａの装着ＯＵＴ側に位置する外側ショルダーブロック１８ｃの装着ＩＮ側の断面高さＨ_c1よりも低く形成されている。すなわち、中央周方向溝１６ｍの装着ＯＵＴ側に位置する陸部の外輪郭形状は、いわゆる「のこぎり状」となっている。
これに対して、本発明の内側陸部に相当する上記第１及び第２の内側ブロック１９ａ，１９ｂは、図２（ｂ）に示すように、断面高さＨが等しく形成されている。また、内側ショルダーブロック１９ｃの上記第２の内側ブロック１９ｂ側の断面高さもＨである。 As shown in FIG. 2 (a), the first and second outer blocks 18a and 18b corresponding to the outer land portion of the present invention have a sectional height at the end on the mounting IN side when viewed in the tire width direction section. is formed higher than the H _a1, H _b1 cross-section of an end of each mounting OUT side height H _a2, H _b2. Further, the groove wall angle α of the circumferential groove 16m adjacent to the mounting OUT side of the second outer block 18b is formed larger than the groove wall angle β of the circumferential groove 16b adjacent to the mounting IN side. The same applies to the first outer block 18a.
The cross-sectional height H _b2 on the mounting OUT side (tire width direction end side) of the second outer block 18b is the first outer block 18a located on the mounting OUT side of the second outer block 18b. Is formed lower than the cross-sectional height H _a1 on the mounting IN side (the center side in the tire width direction), and the cross-sectional height H _a2 on the mounting OUT side of the first outer block 18a is the first outer block. It is formed lower than the mounting iN section height of side H _c1 of the outer shoulder block 18c located on the mounting OUT side 18a. In other words, the outer contour shape of the land portion located on the mounting OUT side of the central circumferential groove 16m is a so-called “sawtooth shape”.
On the other hand, as shown in FIG. 2B, the first and second inner blocks 19a and 19b corresponding to the inner land portion of the present invention have the same sectional height H. The cross-sectional height of the inner shoulder block 19c on the second inner block 19b side is also H.

本例の空気入りタイヤ１０は、上記のように、ＩＮ−ＯＵＴ指定のタイヤであり、装着ＩＮ側のブロックである第１及び第２の内側ブロック１９ａ，１９ｂがフラット形状で、装着ＯＵＴ側のブロックである第１及び第２の外側ブロック１８ａ，１８ｂがのこぎり形状となっているところに特徴がある。すなわち、装着ＩＮ側がフラット形状であるため、高速走行時においても直進性能を確保することができる。一方、装着ＯＵＴ側がのこぎり形状であるので、高速旋回時のような大きな横力が作用した場合でも、上記第１及び第２の外側ブロック１８ａ，１８ｂがＩＮ側にシフトする。これにより、接地面積の減少を抑制してグリップを確保することができるので、直進性能とコーナリング性能とをともに向上させることができる。なお、内側ショルダーブロック１９ｃと外側ショルダーブロック１８ｃもそれぞれ高速直進性能とコーナリング性能の向上に寄与している。
このとき、上記装着ＩＮ側の端部の断面高さＨ_a1と装着ＯＵＴ側の端部の断面高さＨ_a2との差である段差ΔＨとしては、２．０ｍｍ〜２．５ｍｍの範囲とすることが好ましい。上記段差ΔＨが２．０ｍｍ未満である場合には、段差が小さいので、大きな横力が作用したときには、ＯＵＴ側が接地面から浮いてしまって接地面積が減少してコーナリング性能が低下してしまう恐れがある。逆に、上記段差ΔＨが２．５ｍｍを超えると、ブロック踏面の傾きが大きくなりすぎて、高速直進性能が低下するので、上記段差ΔＨを２．０ｍｍ〜２．５ｍｍの範囲とすることが好ましい。
また、上記溝壁角度αと上記溝壁角度βとの差である溝壁角度差（α−β）としては２°〜７°の範囲とすることが好ましい。上記溝壁角度差（α−β）が２°未満である場合には、大きな横力が作用したときにブロックの装着ＯＵＴ側が接地面から浮いてしまって接地面積が減少してコーナリング性能が低下してしまう恐れがある。逆に、溝壁角度差（α−β）が７°を超えると、直進走行時にブロックの装着ＩＮ側が周方向溝１６側に倒れこみやすくなるため、高速直進性能が低下するので、上記溝壁角度差（α−β）を２°〜７°の範囲とすることが好ましい。 The pneumatic tire 10 of this example is an IN-OUT designated tire as described above, and the first and second inner blocks 19a and 19b which are the blocks on the mounting IN side are flat, and the mounting OUT side has a flat shape. A feature is that the first and second outer blocks 18a and 18b, which are blocks, have a saw shape. That is, since the mounting IN side is a flat shape, straight running performance can be ensured even during high speed traveling. On the other hand, since the mounting OUT side has a saw shape, the first and second outer blocks 18a and 18b shift to the IN side even when a large lateral force is applied, such as during high-speed turning. Thereby, since a grip can be secured by suppressing a decrease in the contact area, both the straight running performance and the cornering performance can be improved. Note that the inner shoulder block 19c and the outer shoulder block 18c also contribute to the improvement of the high-speed straight running performance and the cornering performance, respectively.
At this time, the step ΔH, which is the difference between the sectional height H _a1 of the end portion on the mounting IN side and the sectional height H _a2 of the end portion on the mounting OUT side, is in the range of 2.0 mm to 2.5 mm. It is preferable. When the level difference ΔH is less than 2.0 mm, the level difference is small, and when a large lateral force is applied, the OUT side may float from the grounding surface, reducing the grounding area and reducing cornering performance. There is. On the contrary, if the step ΔH exceeds 2.5 mm, the inclination of the block tread becomes too large and the high-speed straight running performance deteriorates. Therefore, the step ΔH is preferably in the range of 2.0 mm to 2.5 mm. .
The groove wall angle difference (α−β), which is the difference between the groove wall angle α and the groove wall angle β, is preferably in the range of 2 ° to 7 °. When the groove wall angle difference (α−β) is less than 2 °, when a large lateral force is applied, the mounting OUT side of the block floats from the grounding surface, reducing the grounding area and lowering the cornering performance. There is a risk of doing. Conversely, if the groove wall angle difference (α−β) exceeds 7 °, the mounting IN side of the block tends to collapse to the circumferential groove 16 side during straight traveling, and thus the high-speed straight traveling performance is reduced. The angle difference (α−β) is preferably in the range of 2 ° to 7 °.

このように本最良の形態では、空気入りタイヤ１０のトレッド１１のタイヤ幅方向中心に、タイヤ周方向に沿って延長するように設けられた中央周方向溝１６ｍを境に、装着ＩＮ側に位置する第１及び第２の内側ブロック１９ａ，１９ｂの形状をフラット形状とするとともに、装着ＯＵＴ側に位置する第１及び第２の外側ブロック１８ａ，１８ｂを、タイヤ幅方向断面でみたときの装着ＩＮ側の端部の断面高さＨ_a1，Ｈ_b1がそれぞれ装着ＯＵＴ側の端部の断面高さＨ_a2，Ｈ_b2よりも高く形成し、かつ、隣接する外側ブロック１８ａ，１８ｂ，１８ｃの輪郭形状がのこぎり形状となるようにしたので、高速走行時における直進性能を確保することができるとともに、高速旋回時のグリップを確保することができるので、コーナリング性能を向上させることができる。
このとき、上記装着ＩＮ側の端部の断面高さＨ_a1と装着ＯＵＴ側の端部の断面高さＨ_a2との差である段差ΔＨを２．０ｍｍ〜２．５ｍｍの範囲に、溝壁角度差（α−β）を２°〜７°の範囲とすることが好ましく、これにより、直進性能とコーナリング性能とを確実に向上させることができる。 As described above, in this best mode, the tire is positioned on the mounting IN side at the center circumferential groove 16m provided in the tire width direction center of the tread 11 of the pneumatic tire 10 so as to extend along the tire circumferential direction. The shape of the first and second inner blocks 19a, 19b to be made is flat, and the mounting IN when the first and second outer blocks 18a, 18b located on the mounting OUT side are seen in the cross section in the tire width direction. The cross-sectional heights H _a1 and H _b1 of the end portion on the side are formed higher than the cross-sectional heights H _a2 and H _b2 of the end portion on the mounting OUT side, respectively, and the contour shape of the adjacent outer blocks 18a, 18b and 18c Since it is shaped like a saw, it is possible to ensure straight running performance during high-speed driving and a grip during high-speed turning, which improves cornering performance. It can be.
At this time, the step ΔH, which is the difference between the cross-sectional height H _a1 of the end portion on the mounting IN side and the cross-sectional height H _a2 of the end portion on the mounting OUT side, is set in the range of 2.0 mm to 2.5 mm. It is preferable that the angle difference (α−β) is in the range of 2 ° to 7 °, whereby the straight running performance and the cornering performance can be reliably improved.

また、本最良の形態では、陸部が周方向溝１６と横溝１７とにより区画された複数のブロック１８，１９である場合について説明したが、これに限るものではなく、周方向に連続した陸部(リブ)であってもよい。また、周方向溝１６はタイヤ周方向に平行な直線状であってもよいし、周方向にジグザク状に形成されていてもよい。横溝１７についても、陸部を貫通するものに限らず、陸部内で終端するものであってもよい。
更に、本発明は、図１（ｂ）に示すような、中心線ＣＬに対称なトレッドパターンを有するタイヤだけでなく、非対称なトレッドパターンを有するタイヤにも適用可能である。
また、上記例では、のこぎり形状の段差（ΔＨ＝Ｈ₂−Ｈ₁）を一定としたが、装着ＯＵＴ側にいくに従って上記段差ΔＨを大きくしてもよい。これにより、横力が更に大きくなった場合でも、接地面積を確実に確保することができる。 In the best mode, the case where the land portion is a plurality of blocks 18 and 19 partitioned by the circumferential groove 16 and the lateral groove 17 has been described. However, the present invention is not limited to this, and the land portion is continuous in the circumferential direction. It may be a part (rib). Further, the circumferential groove 16 may be a straight line parallel to the tire circumferential direction, or may be formed in a zigzag shape in the circumferential direction. The lateral groove 17 is not limited to passing through the land portion, and may be terminated within the land portion.
Furthermore, the present invention is applicable not only to a tire having a tread pattern symmetrical to the center line CL as shown in FIG. 1B but also to a tire having an asymmetric tread pattern.
In the above example, the saw-shaped step (ΔH = H ₂ −H ₁ ) is constant, but the step ΔH may be increased toward the mounting OUT side. Thereby, even when the lateral force is further increased, the ground contact area can be ensured.

図１に示した本発明によるタイヤと、断面高さが等しいブロックを有する従来のタイヤ（比較例）とを準備し、上記各タイヤをスポーツ車に搭載してサーキットにて旋回走行させ、その操縦安定性を調べた。なお、条件は以下の通りである。
タイヤサイズ；235/45R17
サーキット；Ebisu East Course
搭載車両；Imprezza STI ver.
内圧（Fr/Re）；240/190
操縦安定性の評価は、ドライバーのフィーリング評点（１０点満点）により行った。なお、フィーリングは、応答性（レスポンス）、操舵感、グリップの３つについて行った。

表１の結果から、本発明のタイヤの方が従来のタイヤよりも応答性と操舵感とに優れており、高い操縦安定性能を有することが確認された。 A tire according to the present invention shown in FIG. 1 and a conventional tire (comparative example) having blocks having the same cross-sectional height are prepared, and each of the tires is mounted on a sports car and turned on a circuit. Stability was examined. The conditions are as follows.
Tire size; 235 / 45R17
Circuit: Ebisu East Course
Installed vehicle ： Imprezza STI ver.
Internal pressure (Fr / Re); 240/190
Steering stability was evaluated based on the driver's feeling score (up to 10 points). In addition, feeling was performed about three of response (response), a steering feeling, and a grip.

From the results in Table 1, it was confirmed that the tire of the present invention was superior in response and steering feeling than the conventional tire and had high steering stability performance.

このように、本発明によれば、車両の直進走行性能を確保することができるとともに、コーナリング性能を向上させることができるので、車両の高速走行安定性能と操縦安定性能とをともに向上させることができる。 Thus, according to the present invention, the straight running performance of the vehicle can be ensured and the cornering performance can be improved, so that both the high-speed running stability performance and the steering stability performance of the vehicle can be improved. it can.

本発明の最良の形態に係る空気入りタイヤの構成を示す図である。It is a figure which shows the structure of the pneumatic tire which concerns on the best form of this invention. 本発明の空気入りタイヤのブロックを示す図である。It is a figure which shows the block of the pneumatic tire of this invention.

Explanation of symbols

１０空気入りタイヤ、１１トレッド、１２サイドウオール部、
１３ビード部、１３Ｃビードコア、１４ボディプライ、１５ベルト層、
１６ｍ中央周方向溝、１６ａ，１６ｂ外側周方向溝、
１６ｃ，１６ｄ内側周方向溝、１７横溝、１８ａ第１の外側ブロック、
１８ｂ第２の外側ブロック、１８ｃ外側ショルダーブロック、
１９ａ第１の内側ブロック、１９ｂ第２の内側ブロック、
１９ｃ内側ショルダーブロック。 10 pneumatic tires, 11 treads, 12 side wall parts,
13 bead section, 13C bead core, 14 body ply, 15 belt layer,
16m central circumferential groove, 16a, 16b outer circumferential groove,
16c, 16d inner circumferential groove, 17 transverse groove, 18a first outer block,
18b second outer block, 18c outer shoulder block,
19a first inner block, 19b second inner block,
19c Inner shoulder block.

Claims

A pneumatic tire including a plurality of circumferential grooves formed on a tire tread surface so as to extend along a tire circumferential direction, and a land portion partitioned by the circumferential groove, When the tire is mounted on a vehicle, the outer contour shape of the cross section in the tire width direction is a tire in the outer land portion located on the opposite side to the vehicle body side of the specific circumferential groove among the plurality of circumferential grooves. The cross-sectional height of the end portion of the land portion located on the center side in the width direction is formed higher than the cross-sectional height of the end portion of the land portion located on the tire width direction end portion side, and the specific circumferential direction A pneumatic tire characterized in that the vehicle body side land portion located on the vehicle body side of the groove has an equal cross-sectional height.

2. The pneumatic tire according to claim 1, wherein when the plurality of circumferential grooves include a main groove and a sub-groove, the specific circumferential groove is a main groove.

The pneumatic tire according to claim 1, wherein the specific circumferential groove is a circumferential groove located on a tire equatorial plane.

The cross-sectional height of the end portion of the land portion located on the tire width direction end portion side of the outer land portion is the center position of the outer land portion adjacent to the tire width direction end portion side of the outer land portion. The pneumatic tire according to any one of claims 1 to 3, wherein the pneumatic tire is formed lower than a cross-sectional height of an end portion of a land portion.

The difference between the cross-sectional height of the end portion of the land portion located on the center side in the tire width direction of the outer land portion and the cross-sectional height of the end portion of the land portion located on the end side in the tire width direction is 2.0 mm to The pneumatic tire according to claim 4, wherein the tire is 2.5 mm.

The groove wall angle of the circumferential groove adjacent to the center side in the tire width direction of the outer land portion is 2 ° to 7 ° larger than the groove wall angle of the circumferential groove adjacent to the tire width direction end portion side. The pneumatic tire according to any one of claims 1 to 5.