JP2006044368A

JP2006044368A - Pneumatic tire

Info

Publication number: JP2006044368A
Application number: JP2004225775A
Authority: JP
Inventors: Katsumi Hirose; 克己広瀬
Original assignee: Yokohama Rubber Co Ltd
Current assignee: Yokohama Rubber Co Ltd
Priority date: 2004-08-02
Filing date: 2004-08-02
Publication date: 2006-02-16

Abstract

<P>PROBLEM TO BE SOLVED: To provide a pneumatic tire to ensure compatibility between running performance on a paved road surface and running performance on an unpaved road surface. <P>SOLUTION: Since the direction of a blade edge of saw blade-shaped projections T provided on both sides wall surfaces 4 of lug grooves is pointed to a main grooves 1 side in the area from a midpoint A to the main grooves 1 making the midpoint A in the longitudinal direction of the lug groves as a boundary, and pointed to a ground contact end 6 side in the area from the midpoint A to the ground contact end 6, the mud and snow or the like filled in the lug grooves 2 in traveling on the unpaved road surface can be moved to the both directions of the main grooves 2 and the ground contact end 6 respectively and discharged by a flagellar movement of the saw blade-shaped projections T. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

本発明は、空気入りタイヤに関し、さらに詳しくは、舗装路面での走行性能と未舗装路面での走行性能とを両立可能にした空気入りタイヤに関するものである。 The present invention relates to a pneumatic tire, and more particularly to a pneumatic tire that can achieve both running performance on a paved road surface and running performance on an unpaved road surface.

近年、いわゆるＲＶ（レクレーショナル・ヴィークル）用のタイヤでは、舗装路面および未舗装路面の両路面において優れた走行性能を有することが求められるようになってきた。一般に舗装路面での操縦安定性や騒音性能などの走行性能を向上させるには、トレッド面の溝面積を比較的小さくし、特にタイヤ周方向の主溝から接地端に延びるラグ溝の幅を狭くすることが有効である。ところが、このようなタイヤで、未舗装路面（泥濘地や雪道など）を走行すると、ラグ溝に泥や雪が詰まったまま抜けにくくなるため、操縦安定性やトラクション性が低下するという問題があった。 In recent years, tires for so-called RVs (recreational vehicles) have been required to have excellent running performance on both paved and unpaved road surfaces. In general, to improve driving performance and noise performance on paved road surfaces, the groove area of the tread surface is made relatively small, and in particular, the width of the lug groove extending from the main groove in the tire circumferential direction to the ground contact edge is narrowed. It is effective to do. However, when running on an unpaved road surface (such as a muddy ground or a snowy road) with such a tire, mud and snow are stuck in the lag groove, making it difficult to pull out. It was.

未舗装路面での走行性能を向上させるには、溝面積、特にラグ溝幅を増加させて、泥等の溝詰まりを防ぐことが有効な手段である。しかし、このようなタイヤで舗装路面を走行すると、ブロック剛性が低下するため操縦安定性やトラクション性が低下する。このように舗装路面での走行性能と未舗装路面での走行性能とを両立させることは困難であった。 In order to improve traveling performance on an unpaved road surface, it is an effective means to prevent clogging of mud and the like by increasing the groove area, particularly the width of the lug groove. However, when traveling on a paved road surface with such a tire, the block rigidity is lowered, so that the steering stability and the traction property are lowered. Thus, it has been difficult to achieve both running performance on a paved road surface and running performance on an unpaved road surface.

特許文献１は、トレッド表面の溝の詰まりを防止する空気入りタイヤとして、溝の側壁面にタイヤ半径方向外側に刃先を向けた鋸刃状突起を設け、この突起のべん毛運動によって、溝に詰まった石をタイヤ半径方向外側に排出するものを提案している。しかし、この提案では、連続的に溝に泥などが入り込んでくると排出方向がふさがれて十分に排出できなくなるという問題が生じる。 In Patent Document 1, as a pneumatic tire for preventing clogging of a groove on a tread surface, a saw blade-like protrusion having a blade edge facing outward in the tire radial direction is provided on a side wall surface of the groove, and the groove is clogged by flagellar movement of the protrusion. It has been proposed to discharge stones to the outside in the tire radial direction. However, in this proposal, if mud or the like enters the groove continuously, the discharge direction is blocked and the problem cannot be sufficiently discharged.

また、特許文献２は、上記タイヤとは目的が違うが、トレッド表面の溝の溝底または溝壁の少なくとも一方の一部に、鮫肌形状となる鋸刃状突起を走行中の水流抵抗が小さくなる方向に形成した空気入りタイヤを提案している。しかし、この提案は、突起によって排水性能を高めてハイドロプレーニング現象を発生しにくくするものであり、突起の方向が一方向となっているので、未舗装路面を走行して泥や雪などが詰まった場合には、泥や雪を一方向にしか移動させることができないため、途中で詰まりを発生し、十分な走行性能を得ることはできない。
特開２００２−３６８２２号公報特開２００２−３６８２０号公報 Further, although the purpose of Patent Document 2 is different from that of the tire described above, the water flow resistance during running of a sawtooth projection having a ridged skin shape on at least one of the groove bottom or groove wall of the groove on the tread surface is small. A pneumatic tire formed in the following direction is proposed. However, this proposal improves the drainage performance by the protrusions and makes the hydroplaning phenomenon less likely to occur, and since the protrusions are unidirectional, they run on unpaved roads and become clogged with mud and snow. In such a case, mud and snow can be moved only in one direction, so that clogging occurs on the way and sufficient traveling performance cannot be obtained.
JP 2002-36822 A JP 2002-36820 A

本発明の目的は、舗装路面での走行性能と未舗装路面での走行性能との両立を可能にした空気入りタイヤを提供することにある。 An object of the present invention is to provide a pneumatic tire that enables both running performance on a paved road surface and running performance on an unpaved road surface.

上記目的を達成するため本発明の空気入りタイヤは、トレッド面にタイヤ周方向に延びる少なくとも１本の主溝と、該主溝から接地端に抜ける多数のラグ溝をタイヤ周方向に間欠的に設けた空気入りタイヤにおいて、前記ラグ溝の両側壁面にそれぞれ複数の鋸刃状突起を設け、これら鋸刃状突起のうち、前記ラグ溝の長手方向の中間点から前記主溝までの領域に配置した鋸刃状突起は、その刃先を前記主溝側へ向け、前記中間点から前記接地端までの領域に配置した鋸刃状突起は、その刃先を前記接地端側へ向けたことを特徴とするものである。 In order to achieve the above object, the pneumatic tire of the present invention intermittently includes at least one main groove extending in the tire circumferential direction on the tread surface and a number of lug grooves extending from the main groove to the ground contact end in the tire circumferential direction. In the provided pneumatic tire, a plurality of saw blade projections are provided on both side walls of the lug groove, and the saw blade projections are arranged in a region from the midpoint in the longitudinal direction of the lug groove to the main groove. The saw blade-shaped protrusion is directed to the main groove side, and the saw blade-shaped protrusion disposed in the region from the intermediate point to the ground end is directed to the ground end side. To do.

本発明の空気入りタイヤによれば、ラグ溝の両側壁面に設けた鋸刃状突起の刃先の方向をラグ溝の長手方向中間点を境界として、中間点から主溝までの領域では主溝側に向け、中間点から接地端までの領域では接地端側に向けたので、未舗装路面の走行時にラグ溝に詰まる泥や雪などを鋸刃状突起のべん毛運動で主溝と接地端との両方向へそれぞれ移動させて排出させることができる。したがって、ラグ溝面積を舗装路面走行時の機能に合わせて狭幅にしてあっても、未舗装路面での操縦安定性やトラクション性などの走行性能を向上させることが可能となり、舗装路面での走行性能と未舗装路面での走行性能を両立させることができる。 According to the pneumatic tire of the present invention, the direction of the blade edge of the saw blade projection provided on the both side wall surfaces of the lug groove is the main groove side in the region from the intermediate point to the main groove with the longitudinal intermediate point of the lug groove as a boundary. In the region from the midpoint to the grounding edge, the mud or snow clogged in the lug groove when traveling on an unpaved road surface is moved between the main groove and the grounding edge by flagella movement of the saw blade projection. It can be moved in both directions and discharged. Therefore, even if the lug groove area is narrowed according to the function when running on paved roads, it becomes possible to improve driving performance such as steering stability and traction on unpaved roads, and on paved roads. Both driving performance and driving performance on an unpaved road surface can be achieved.

以下、本発明の空気入りタイヤを図に示した実施形態に基づいて説明する。図４は、本発明の空気入りタイヤに設けたトレッドパターンの一例を示す。トレッド面５には４本のタイヤ周方向に延長する主溝１と、左右２本ずつの主溝１、１間を横切る横溝３とにより幅方向中央部にブロック列Ｂが形成されている。また、両外側の主溝１、１からは、それぞれトレッド面５の接地端に向けて多数のラグ溝２が、タイヤ周方向に所定の間隔をおいて形成されている。 Hereinafter, the pneumatic tire of the present invention will be described based on the embodiments shown in the drawings. FIG. 4 shows an example of a tread pattern provided on the pneumatic tire of the present invention. A block row B is formed at the center in the width direction on the tread surface 5 by four main grooves 1 extending in the tire circumferential direction and two horizontal grooves 3 crossing between the two main grooves 1 on the left and right sides. A large number of lug grooves 2 are formed from the outer main grooves 1 and 1 toward the ground contact end of the tread surface 5 at predetermined intervals in the tire circumferential direction.

ラグ溝２には図１に拡大して示すように、両側壁面４に、ラグ溝２の長手方向の中間点Ａから主溝１に至るまでの領域に刃先を主溝１側に向けた鋸刃状突起Ｔ１が形成され、中間点Ａから接地端６に至るまでの領域に刃先を接地端６側に向けた鋸刃状突起Ｔ２が形成されている。 As shown in enlarged view in FIG. 1, the lug groove 2 is a saw having cutting edges directed to the main groove 1 side on both side wall surfaces 4 in the region from the longitudinal intermediate point A of the lug groove 2 to the main groove 1. A blade-like protrusion T1 is formed, and a saw-tooth protrusion T2 is formed in a region from the intermediate point A to the grounding end 6 with the blade tip facing the grounding end 6 side.

このように、ラグ溝２にはタイヤ幅方向において、中間点Ａを境界にして刃先を相反する方向に向けた鋸刃状突起Ｔが形成されている。この中間点Ａはラグ溝の長さ方向中心Ｍからラグ溝長さＬ２の±１０％の範囲Ｌｍ内にあることが好ましい。中間点Ａをこの範囲Ｌｍ内にするとラグ溝２に詰まった物を主溝１や接地端６まで移動させる距離が短くなり、早く円滑に排出することができる。 As described above, the lug groove 2 is formed with the saw blade projection T in the tire width direction with the intermediate point A as a boundary and the cutting edge facing in the opposite direction. The intermediate point A is preferably within a range Lm of ± 10% of the lug groove length L2 from the lug groove lengthwise center M. When the intermediate point A is within this range Lm, the distance for moving the object clogged in the lug groove 2 to the main groove 1 or the ground contact end 6 is shortened, and can be discharged quickly and smoothly.

図２に示すようにトレッド面５の平面視において、鋸刃状突起Ｔの内側面とラグ溝の側壁面４とがなす角度αは１０〜３０度、突起の刃先角度βは０．２５α〜０．７５αにして、かつ突起の内側面に沿う長さＬ１は２〜５ｍｍとすることが好ましい。 As shown in FIG. 2, in a plan view of the tread surface 5, the angle α formed by the inner surface of the saw blade projection T and the side wall surface 4 of the lug groove is 10 to 30 degrees, and the blade edge angle β of the projection is 0.25α. The length L1 along the inner surface of the protrusion is preferably 2 to 5 mm and 0.75α.

鋸刃状突起Ｔの内側面とラグ溝の側壁面４とがなす角度αが１０度未満であるとべん毛運動による鋸刃状突起Ｔの動きが少なく排出効果が小さくなり、３０度を超えると鋸刃状突起Ｔが欠けやすくなる。また、刃先角度βが０．２５α未満であると鋸刃状突起Ｔが欠けやすく、０．７５αを超えると鋸刃状突起Ｔの動きが少なく排出効果が小さくなる。また、突起の内側面に沿う長さＬ１が２ｍｍ未満であるとべん毛運動による排出効果が小さくなり、５ｍｍを超えると鋸刃状突起Ｔが欠けやすくなる。 When the angle α formed between the inner surface of the saw blade projection T and the side wall surface 4 of the lug groove is less than 10 degrees, the movement of the saw blade protrusion T due to flagellar movement is small, and the discharging effect is small. The sawtooth projection T is likely to be chipped. Further, when the blade edge angle β is less than 0.25α, the saw blade projection T is likely to be chipped, and when it exceeds 0.75α, the saw blade projection T has little movement and the discharge effect is small. Further, if the length L1 along the inner surface of the protrusion is less than 2 mm, the discharging effect by flagellar movement is reduced, and if it exceeds 5 mm, the saw-tooth protrusion T is likely to be chipped.

鋸刃状突起Ｔの数は、図１に示すように中間点Ａから主溝１までおよび中間点Ａから接地端６までの各領域において、ラグ溝２の側壁面４片側当り３個以上形成されていることが好ましい。ラグ溝２の側壁面４片側当り３個未満であると、べん毛運動による排出効果が小さくなる。 As shown in FIG. 1, three or more saw blade projections T are formed per one side of the side wall surface 4 of the lug groove 2 in each region from the intermediate point A to the main groove 1 and from the intermediate point A to the grounding end 6. It is preferable that When the number of the side walls 4 of the lug groove 2 is less than 3 per side, the discharge effect due to flagellar movement is reduced.

それと同時に、図３に示すように鋸刃状突起Ｔのトレッド面５からのラグ溝の深さ方向の長さ（突起形成深さＤ１）は、ラグ溝深さＤの７０〜９０％の範囲であることが好ましい。鋸刃状突起Ｔがトレッド面５からラグ溝深さＤの７０％未満までしか形成されていないと、べん毛運動による排出効果が小さくなる。一方で、ラグ溝深さＤの９０％を超えて形成されていると、ラグ溝底との間隔が小さくなり鋸刃状突起Ｔの動きが規制されて、べん毛運動による排出効果が低減する。 At the same time, as shown in FIG. 3, the length in the depth direction of the lug groove from the tread surface 5 of the saw blade projection T (projection formation depth D1) is in the range of 70 to 90% of the lug groove depth D. It is preferable that If the saw-tooth projection T is formed only from the tread surface 5 to less than 70% of the lug groove depth D, the discharging effect due to flagellar movement is reduced. On the other hand, if it is formed to exceed 90% of the lug groove depth D, the distance from the bottom of the lug groove is reduced and the movement of the saw blade projection T is restricted, and the discharge effect by flagellar motion is reduced. To do.

このタイヤのラグ溝２に泥や雪などが詰まった場合は、走行によりトレッド面５が変形することで鋸刃状突起Ｔが、べん毛運動をして、ラグ溝２に詰まった物を鋸刃状突起Ｔの刃先方向に移動させ、主溝１と接地端６とに排出して最終的にトレッド面５から排除する。これにより、未舗装路面でも操縦安定性やトラクション性が低下することなく、良好な走行性能を得ることができる。また、溝詰まり対策として特別に溝面積、溝幅を大きくする必要がないため舗装路面での走行騒音、操縦安定性などを悪化させることもなく、良好な走行性能を得ることができる。このように、舗装、未舗装の両路面において優れた走行性能を確保することができる。 When mud or snow is clogged in the lug groove 2 of the tire, the tread surface 5 is deformed by traveling, and the saw blade projection T performs flagella movement, so that the clogged material in the lug groove 2 is removed. The saw blade projection T is moved in the direction of the blade edge, discharged to the main groove 1 and the grounding end 6 and finally removed from the tread surface 5. Thereby, even on an unpaved road surface, good running performance can be obtained without lowering steering stability and traction. In addition, since it is not necessary to increase the groove area and groove width as a countermeasure against clogging, good running performance can be obtained without deteriorating running noise and steering stability on the paved road surface. Thus, excellent running performance can be ensured on both paved and unpaved road surfaces.

なお、本発明は実施形態で示したトレッドパターンに限定されず、トレッド面にラグ溝を有する空気入りタイヤに適用することができる。 In addition, this invention is not limited to the tread pattern shown by embodiment, It can apply to the pneumatic tire which has a lug groove in a tread surface.

タイヤサイズを２６５／６５Ｒ１７、トレッドパターンを図４に示すものとして、鋸刃状突起の刃先をラグ溝の長手方向の中間点を境界として、ラグ溝の長手方向に相反する方向に向けて、鋸刃状突起の数を中間点から主溝および中間点から接地端に至るそれぞれの領域において、ラグ溝の両側壁にそれぞれ３個設け、中間点の位置をラグ溝の長さ方向中心からラグ溝長さの±１０％の範囲内とすることを共通の条件として、タイヤのラグ溝の仕様（突起の内側面とラグ溝の側壁面とがなす角度α、突起の刃先角度β、突起長さＬ１、突起形成深さＤ１）を表１に示すように変えたタイヤを４種類（実施例１〜４）、従来のタイヤを１種類（従来例）の合計５種類製作した。従来のタイヤはラグ溝の仕様のみ実施例と変えたもので、鋸刃状突起の刃先方向をすべて同一方向に向け、角度α、角度β、突起長さＬ１および突起形成深さＤ１を表１のように設定したものである。 The tire size is 265 / 65R17, the tread pattern is shown in FIG. 4, and the cutting edge of the saw blade projection is pointed in the direction opposite to the longitudinal direction of the lug groove with the middle point in the longitudinal direction of the lug groove as a boundary. In each region from the intermediate point to the main groove and from the intermediate point to the grounding end, three edge projections are provided on each side wall of the lug groove, and the position of the intermediate point is the lug groove from the longitudinal center of the lug groove. The tire lug groove specifications (angle α formed between the inner surface of the protrusion and the side wall surface of the lug groove, blade edge angle β of the protrusion, protrusion length) L1 and protrusion formation depth D1) were changed as shown in Table 1, and four types (Examples 1 to 4) of tires and one type of conventional tire (conventional example) were manufactured in total. The conventional tire is the same as the embodiment except for the lug groove specifications. The blade edge direction of the saw blade-like protrusions are all directed in the same direction, and the angle α, angle β, protrusion length L1, and protrusion formation depth D1 are shown in Table 1. It is set like this.

これらのタイヤを内圧２００ｋＰａに調整し、１７×７１／２ＪＪのリムに組み付け、これを四輪駆動車に装着して評価テストを実施した。評価項目は泥濘地走行性能、騒音性能、操縦安定性、突起の欠け具合である。結果は表１に示すとおりであり、表中の数値は大きい程、性能が良いことを示している。 These tires were adjusted to an internal pressure of 200 kPa, assembled to a rim of 17 × 7 1/2 JJ, and mounted on a four-wheel drive vehicle to perform an evaluation test. The evaluation items are muddy road running performance, noise performance, handling stability, and protrusion chipping. The results are as shown in Table 1. The larger the numerical value in the table, the better the performance.

［泥濘地走行性能］
泥濘地を走行した時のテストドライバーによるフィーリング評価で、主に操縦安定性やトラクション性能について従来例を基準の１００として指数で評価した。 [Muddyland running performance]
In the feeling evaluation by a test driver when traveling in a muddy area, the steering stability and the traction performance were mainly evaluated with an index based on the conventional example of 100.

［騒音性能］
平滑な舗装路面を時速６０ｋｍ／ｈにて走行したときの車内中央における騒音レベルを計測して従来例を基準の１００として指数で評価したものである。 [Noise performance]
The noise level at the center of the vehicle when traveling on a smooth paved road surface at a speed of 60 km / h was measured, and the conventional example was evaluated as an index based on 100 as a reference.

［操縦安定性］
平滑な舗装路面のテストコースにてテストドライバーによるフィーリング評価で、主にレーンチェンジやコーナリングについて１０点満点で評価した。 [Steering stability]
In a test course on a smooth paved road surface, the driver evaluated the feeling mainly on lane changes and cornering on a 10-point scale.

［欠けの発生度合い］
平滑な舗装路面のテストコースにて地点ａから５００ｍの間に時速４０ｋｍ／ｈから１００ｋｍ／ｈまで加速後、時速１００ｋｍ／ｈにて１ｋｍ走行した後、地点ｂから５００ｍの間に時速１００ｋｍ／ｈから４０ｋｍ／ｈまで減速し、その後時速４０ｋｍ／ｈにて１ｋｍ走行して地点ａにもどる１周３ｋｍの周回コースを２０周した後の突起欠けの有無を調査したものである。 [Degree of chipping]
After accelerating from 40 km / h to 100 km / h between point a and 500 m on a smooth paved road test course, driving 1 km at speed of 100 km / h and then 100 km / h between point b and 500 m From 40 to 40 km / h, and then traveled 1 km at a speed of 40 km / h and returned to point a.

この結果から実施例１〜４の本発明のタイヤは、鋸刃状突起の数、刃先の方向、中間点の位置、突起の内側面とラグ溝の側壁面とがなす角度α、突起の刃先角度β、突起長さＬ１、突起形成深さＤ１を本発明で特定した範囲にしたことにより、従来例のタイヤに比べて、泥濘地走行性能を大幅に向上させることができ、舗装路面での騒音性能および操縦安定性については同等の性能を有していることが確認できた。また、突起の欠けも生ずることもなかった。 From these results, the tires of the present invention of Examples 1 to 4 show the number of saw blade projections, the direction of the blade edge, the position of the intermediate point, the angle α formed between the inner surface of the protrusion and the side wall surface of the lug groove, and the blade edge of the protrusion. By making the angle β, the protrusion length L1, and the protrusion formation depth D1 within the ranges specified in the present invention, the muddy road running performance can be greatly improved compared to the conventional tires, and on the paved road surface. It was confirmed that the noise performance and steering stability were equivalent. Moreover, no chipping of the protrusions occurred.

本発明に係るラグ溝の形状を説明するラグ溝一部拡大平面図である。It is a lug groove partial enlarged plan view explaining the shape of the lug groove concerning the present invention. 本発明に係るラグ溝の鋸刃状突起の形状を説明する鋸刃状突起の拡大平面図である。It is an enlarged plan view of the saw blade projection for explaining the shape of the saw blade projection of the lug groove according to the present invention. 本発明に係るラグ溝の形状を説明するラグ溝の拡大斜視図である。It is an expansion perspective view of the lug groove explaining the shape of the lug groove concerning the present invention. 本発明の空気入りタイヤのトレッドパターンを示すトレッド平面図である。It is a tread top view which shows the tread pattern of the pneumatic tire of this invention.

符号の説明Explanation of symbols

１主溝（タイヤ周方向溝）
２ラグ溝
３横溝
４ラグ溝の側壁面
５トレッド面
６接地端
Ａラグ溝の長手方向の中間点
Ｔ鋸刃状突起
Ｔ１主溝側に刃先を向けた鋸刃状突起
Ｔ２接地端側に刃先を向けた鋸刃状突起 1 Main groove (tire circumferential groove)
2 Lag groove 3 Lateral groove 4 Side wall surface of lug groove 5 Tread surface 6 Grounding end A Intermediate point in the longitudinal direction of lug groove T Saw blade projection T1 Saw blade projection with the blade edge toward the main groove T2 Blade edge toward the ground edge Saw blade projection

Claims

トレッド面にタイヤ周方向に延びる少なくとも１本の主溝と、該主溝から接地端に抜ける多数のラグ溝をタイヤ周方向に間欠的に設けた空気入りタイヤにおいて、前記ラグ溝の両側壁面にそれぞれ複数の鋸刃状突起を設け、これら鋸刃状突起のうち、前記ラグ溝の長手方向の中間点から前記主溝までの領域に配置した鋸刃状突起は、その刃先を前記主溝側へ向け、前記中間点から前記接地端までの領域に配置した鋸刃状突起は、その刃先を前記接地端側へ向けた空気入りタイヤ。 In a pneumatic tire in which at least one main groove extending in the tire circumferential direction on the tread surface and a number of lug grooves extending from the main groove to the grounding end are intermittently provided in the tire circumferential direction, A plurality of saw blade-like projections are provided, and of these saw blade-like projections, the saw blade projections arranged in the region from the midpoint of the lug groove in the longitudinal direction to the main groove have their blade tips on the main groove side. The saw blade projections arranged in the region from the intermediate point to the ground contact end are pneumatic tires whose blade tips are directed toward the ground contact end.

前記中間点を前記ラグ溝の長さ方向中心からラグ溝長さＬ２の±１０％の範囲内に設けた請求項１に記載の空気入りタイヤ。 The pneumatic tire according to claim 1, wherein the intermediate point is provided within a range of ± 10% of the lug groove length L2 from the longitudinal center of the lug groove.

トレッド面の平面視において、前記鋸刃状突起の内側面と前記ラグ溝の側壁面とがなす角度αが１０〜３０度で、前記突起の刃先角度βが０．２５α〜０．７５αであり、かつ前記突起の内側面に沿う長さが２〜５ｍｍである請求項１または２に記載の空気入りタイヤ。 In a plan view of the tread surface, the angle α formed by the inner surface of the saw blade projection and the side wall surface of the lug groove is 10 to 30 degrees, and the blade edge angle β of the projection is 0.25α to 0.75α. The pneumatic tire according to claim 1, wherein a length along the inner side surface of the protrusion is 2 to 5 mm.

前記中間点から主溝までおよび前記中間点から接地端までの各領域におけるラグ溝の側壁面片側当りの鋸刃状突起の数が少なくとも３個であり、かつ前記突起のトレッド面からラグ溝の深さ方向の長さが該ラグ溝深さの７０〜９０％の範囲である請求項１〜３のいずれかに記載の空気入りタイヤ。

The number of saw blade projections per side wall surface side of the lug groove in each region from the intermediate point to the main groove and from the intermediate point to the grounding end is at least three, and from the tread surface of the protrusion to the lug groove The pneumatic tire according to any one of claims 1 to 3, wherein a length in a depth direction is in a range of 70 to 90% of the depth of the lug groove.