JPH0521441Y2

JPH0521441Y2 -

Info

Publication number: JPH0521441Y2
Application number: JP1986040367U
Authority: JP
Priority date: 1986-03-18
Filing date: 1986-03-18
Publication date: 1993-06-02
Anticipated expiration: 2001-03-18
Also published as: JPS62151101U

Description

[Detailed explanation of the idea]

（産業上の利用分野）本考案は空気入りタイヤ、例えば乗用車、小型
トラツク、大型トラツクおよびバス等に装着され
高速走行するラグタイプのトレツド模様を有する
空気入りタイヤに関する。（従来の技術）従来の空気入りタイヤとしては、例えば、第５
図に示すようなものがある。同図のトレツド１は
その両側端部１ａにほぼタイヤ軸方向で対をなす
ラグ３と、ラグ３に隣接するラグ溝５を有し、ラ
グ３とラグ溝５とをタイヤ周方向に交互に多数配
置している。ラグ３の横断面形状は、第６図に示
すように、ラグ３の両側壁面３ａはほぼ一様な傾
斜をなしてラグ溝５を形成している。ラグ３のタ
イヤ周方向の両側壁面３ａ、および３a₂が、ラグ
３の上端縁３ｂにおいて、ラグ表面３ｃに垂直な
面Ｐとのなす角度α₁およびα₂はほぼ同じか、やや
異なる程度である。（考案が解決しようとする問題点）しかしながら、このような従来のラグ３を有す
るいわゆるラグタイプのタイヤが路面上を転動す
ると、ラグ溝５が形成する空間内の空気が、トレ
ツド１と路面との間で圧縮され、次いで膨張して
音を発生する、いわゆるポンピング音を発生し、
走行時のタイヤ騒音の主要因となるという問題点
がある。これを解決するため、ラグ溝５の溝幅W₅を小
さくしてラグ溝５内の体積を減少し、圧縮・膨張
する空気量を少なくすることも考えられるが、ラ
グ溝５の溝幅W₅を小さくすると、泥寧地および
雪路等の軟弱路を走行時のトラクシヨン性能が低
下する。そこで、本考案は、各種路面におけるタイヤの
走行時のトラクシヨン性能を犠牲にすることなし
に、タイヤの走行時の騒音を低減した空気入りタ
イヤを提供することを目的とする。（問題点を解決するための手段）本考案の空気入りタイヤは、タイヤのトレツド
の両側端部にほぼタイヤ軸方向で対をなすラグ
と、ラグに隣接するラグ溝とを有し、ラグとラグ
溝とがタイヤ周方向に交互に多数配置された空気
入りタイヤにおいて、ラグが少なくとも一方のラ
グ側壁に断面階段状にラグ溝内に張出す張出部を
有し、張出部がトレツドの両側端からトレツド中
央に向つてトレツド幅の20％以上設けられ、張出
部の張出し高さｈがラグ溝の深さＨの20〜50％を
有し、張出部の張出し幅ｗがラグ溝の張出し幅を
含めた全溝幅Ｗの20〜70％を有することを特徴と
している。ここに、ラグ側壁の張出部がトレツドの両側端
からトレツド中央に向つて、トレツド幅の20％以
上としたのは、20％未満ではラグ溝５内の体積の
減少率が少なくタイヤ騒音の低減効果が少ないか
らである。また、張出部の張出し高さｈをラグ溝の溝深さ
Ｈの20〜50％にしたのは、20％未満ではラグ溝５
内の体積の減少率が少なく、タイヤ騒音の低減効
果が少なく、50％を超えると、ラグの剛性が強く
なり過ぎ、タイヤが路面上を転動する際、ラグが
路面を叩いて発生する、いわゆるラグ打音が強く
なり過ぎ、さらに、軟弱路を走行時にラグを路面
に押し込む際の抵抗が増加し、トラクシヨン性能
が低下するからである。また、張出部の張出し幅ｗを、ラグ溝の全溝幅
Ｗの20〜70％としたのは、20％未満では、ラグ溝
内の体積の減少率が少なく、タイヤの騒音の低減
効果が少なく、70％を超えると、ラグ間のラグ溝
底の断面曲率が小さくなり過ぎ、走行時の屈曲疲
労が大きくなりクラツク等の故障が発生し易くな
るからである。（作用）本考案の空気入りタイヤはラグが少なくとも一
方のラグ側壁に断面階段状にラグ溝内に張出す張
出部を有し、張出部のトレツド幅方向の長さ、張
出し高さ、張出し幅は前述の範囲を有しているの
で、ラグ溝の体積は減少してラグ溝内の空気は減
少し、タイヤの転動時にラグ溝と路面の間で圧縮
され、膨張する空気量が大幅に減少して、タイヤ
騒音は従来の空気入りタイヤに比較して大幅に減
少する。また、ラグ側縁部およびラグ全体の剛性
が弱すぎる（従来より低下する）ことも強すぎる
こともないから、ラグ打音の発生や軟弱路面での
押し込み抵抗の増加といつた問題が解消され、各
種路面でのトラクシヨン性能が十分に確保され
る。（実施例）以下、本考案の実施例を図面に基づき説明す
る。第１〜３図は本考案に係る空気入りタイヤの一
実施例を示す図である。同図において、空気入り
タイヤ（タイヤサイズ31×10.5R15）のトレツド
１２はその両側端部１２ａにほぼタイヤ軸方向Ａ
で対をなすラグ１３と、ラグ１３に隣接するラグ
溝１５とを有し、ラグ１３とラグ溝１５とがタイ
ヤ周方向Ｂ方向に交互に多数配置されている。ま
た、トレツド１２の中央部１２ｂにはブロツク１
７がラグ１３と周方向のジグザグ溝１８を挟み、
かつトレツド中央２０の周方向溝２１を挟み左右
にほぼ対応して配置され、いわゆるリブ、ラグタ
イプに似たトレツド模様を有している。ラグ１３は少なくとも一方（この実施例では両
方）のラグ側壁１３ａに断面階段状にラグ溝１５
内に張出す張出部２３を有している。また、ブロ
ツク１７の周方向の一側壁１７ａにはジグザグ溝
１８内に張出す張出部２５を有している。ラグ１
３の張出部２３はトレツド１２の両側端１２ｃか
らトレツド中央２０に向つてほぼタイヤ断面方向
Ａの張出し長さTW₂₃を有し、この張出し長さ
TW₂₃はトレツド幅TW₁₂の20％以上（この実施
例では両側で51％）設けられている。張出部２３
の張出し高さh₂₃（この実施例では５mm）が、第３
図に実線で示すように、ラグ溝１５の深さH₁₅
（この実施例では15mm）の20〜50％（この実施例
では33％）を有し、張出部２３の両方の（w_23a、
w_23b）の和の張出し幅w₂₃（この実施例ではw_23a、
w_23bともに7.5mm）がラグ溝１５の張出し幅w₂₃を
含めた全溝幅W₁₅（この実施例では30mm）の20〜
70％（この実施例では50％）を有している。上記
以外は通常の空気入りラジアルタイヤと同じであ
る。次に作用について説明する。本考案に空気入りタイヤ１１はラグ１３のラグ
側壁１３ａに断面階段状にラグ溝１５内に張出す
張出部２３を有しているので、従来の空気入りタ
イヤのラグ溝２８（第３図には点線で示してい
る）の体積より大幅に減少し、転動時トレツド１
２と路面との間で圧縮・膨張する空気量が大幅に
減少している。したがつて、タイヤ騒音は大幅に
減少する。また、従来のものに対しラグ１３の剛
性の増減は少なく、接地部からの力の伝達の面で
も軟弱路面での路面内への食い込みの面でも十分
なものになるから、各種路面におけるトラクシヨ
ン性能が十分に確保できる。さらに溝底１５ａの
断面曲率も十分に大きく、ゴムの屈曲疲労も少な
くクラツクの発生もない。なお、前述の実施例においては、張出部２３は
ラグ１３の両方のラグ側壁１３ａにほぼ対象に断
面階段状に１段でラグ溝１５内に張出す場合につ
いて説明したが、本考案においては、第４図ａ〜
ｄに示す他のそれぞれの実施例のように、一方の
ラグ側壁１３ａのみに断面形状で１段の張出部３
０（第４図ａ）を、または、２段の張出部３２
（第４図ｂ）を、設けてもよい。さらに、両方の
ラグ側壁１３ａに１段以上の張出部を設けてもよ
い、すなわち、両方のラグ側壁１３ａに１段で張
出し幅の異なる張出部３４ａおよび３４ｂ（第４
図ｃ）を、または、一方は１段の張出部３６ａ
を、他方は２段の張出部３６ｂ（第４図ｄ）を、
さらにまた、両方に２段の張出部３８ａおよび３
８ｂ（第４図ｅ）を、設けてもよい。次に、試験タイヤ（タイヤサイズ31×
10.50R15）を３種類（実施例１種、比較例２種）
を準備して本考案の効果を確認した。試験タイヤ
の実施例は前述の第１〜３図に示したものと同じ
である。比較例１は従来タイヤで、ラグ溝の断面
形状が、前述の第３図に点線で示すラグ溝２８で
溝幅W₁₅は溝底までほぼ広い溝幅を有しており、
他の構成は実施例と同じである。比較例２は、従
来タイヤでラグ溝の断面形状が、前述第３図に一
点鎖線で示すラグ溝２９で溝幅W₂₉は溝底までほ
ぼ狭い溝幅を有しており、他の構成は実施例と同
じである。これら試験タイヤは同様に製造され
た。試験は試験路を走行時に発生する騒音性能と、
軟弱路を走行時のトラクシヨン性能について行つ
た。各試験タイヤは試験車に装着し、それぞれ所
定の負荷で所定の速度で走行し、テストドライバ
ーのフイーリング試験により評価した。評価結果
は比較例１（従来タイヤ）の結果を100として指数
表示した。指数は大きい程良いことを示す。評価結果は、次表に示す。 (Industrial Field of Application) The present invention relates to a pneumatic tire, such as a pneumatic tire having a lug-type tread pattern, which is mounted on passenger cars, small trucks, large trucks, buses, etc. and runs at high speed. (Prior art) As a conventional pneumatic tire, for example,
There is something like the one shown in the figure. The tread 1 in the figure has lugs 3 that form a pair in the tire axial direction and lug grooves 5 adjacent to the lugs 3 at both end portions 1a thereof, and the lugs 3 and the lug grooves 5 are arranged alternately in the tire circumferential direction. Many are placed. As shown in FIG. 6, the cross-sectional shape of the lug 3 is such that both side wall surfaces 3a of the lug 3 form a substantially uniform slope to form a lug groove 5. The angles α 1 and α 2 that both side wall surfaces 3a and 3a ₂ of the lug 3 in the tire circumferential direction make with a plane P perpendicular to the lug surface 3c at the upper edge _3b of the lug ₃ are approximately the same or slightly different. be. (Problems to be Solved by the Invention) However, when a so-called lug type tire having such conventional lugs 3 rolls on a road surface, air in the space formed by the lug grooves 5 flows between the tread 1 and the road surface. It is compressed between the
There is a problem that this is the main cause of tire noise during driving. In order to solve this problem, it is possible to reduce the groove width W ₅ of the lug groove 5 to reduce the volume inside the lug groove 5 and reduce the amount of compressed and expanded air. If ₅ is made small, the traction performance will decrease when driving on soft roads such as muddy terrain and snowy roads. Therefore, an object of the present invention is to provide a pneumatic tire that reduces noise when the tire runs on various road surfaces without sacrificing traction performance when the tire runs on various road surfaces. (Means for Solving the Problems) The pneumatic tire of the present invention has lugs that form a pair in the axial direction of the tire at both ends of the tread of the tire, and a lug groove adjacent to the lugs. In a pneumatic tire in which a large number of lug grooves are arranged alternately in the circumferential direction of the tire, the lug has a protruding part on at least one lug side wall that protrudes into the lug groove with a stepped cross section, and the protruding part is a part of the tread. It is provided from both ends toward the center of the tread by 20% or more of the tread width, and the overhang height h of the overhang is 20 to 50% of the depth H of the lug groove, and the overhang width w of the overhang is equal to It is characterized by having 20 to 70% of the total groove width W including the overhang width of the groove. The reason why the protruding parts of the lug side walls are made to be at least 20% of the tread width from both ends of the tread toward the center of the tread is because if it is less than 20%, the volume within the lug groove 5 will decrease less and the tire noise will be reduced. This is because the reduction effect is small. Also, the reason why the overhang height h of the overhang part is set to 20 to 50% of the groove depth H of the lug groove is that if it is less than 20%, the lug groove depth
The reduction rate of the internal volume is small, and the effect of reducing tire noise is small.If it exceeds 50%, the rigidity of the lugs becomes too strong, and when the tire rolls on the road surface, the lugs hit the road surface. This is because the so-called lug hitting sound becomes too strong, and furthermore, the resistance when pushing the lug into the road surface increases when driving on a soft road, resulting in a decrease in traction performance. In addition, the overhang width w of the overhang part is set to 20 to 70% of the total groove width W of the lug groove, because if it is less than 20%, the volume reduction rate in the lug groove will be small and the tire noise will be reduced. If the ratio exceeds 70%, the cross-sectional curvature of the bottom of the lug groove between the lugs becomes too small, resulting in increased bending fatigue during running, making it more likely that failures such as cracks will occur. (Function) The pneumatic tire of the present invention has a lug on at least one lug side wall that protrudes into the lug groove with a stepped cross section, and the length of the protrusion in the tread width direction, the protrusion height, Since the overhang width is within the above range, the volume of the lug groove decreases and the air inside the lug groove decreases, and the amount of air that is compressed and expanded between the lug groove and the road surface when the tire rolls is reduced. Significantly reduced, tire noise is significantly reduced compared to traditional pneumatic tires. In addition, the rigidity of the lug side edges and the lug as a whole is neither too weak (lower than before) nor too strong, which eliminates problems such as lug hitting noise and increased pushing resistance on soft roads. , sufficient traction performance on various road surfaces is ensured. (Example) Hereinafter, an example of the present invention will be described based on the drawings. 1 to 3 are diagrams showing an embodiment of a pneumatic tire according to the present invention. In the same figure, the tread 12 of a pneumatic tire (tire size 31×10.5R15) is located at both end portions 12a of the tire in the axial direction A.
The tire has a pair of lugs 13 and a lug groove 15 adjacent to the lug 13, and a large number of lugs 13 and lug grooves 15 are arranged alternately in the tire circumferential direction B. In addition, a block 1 is provided in the central portion 12b of the tread 12.
7 sandwiching the lug 13 and the circumferential zigzag groove 18,
They are arranged substantially corresponding to each other on the left and right sides of the circumferential groove 21 in the center 20 of the tread, and have a tread pattern resembling a so-called rib or lug type. The lug 13 has a lug groove 15 in at least one (both in this embodiment) lug side wall 13a with a stepped cross section.
It has a protruding portion 23 that protrudes inward. Further, one side wall 17a in the circumferential direction of the block 17 has a projecting portion 25 projecting into the zigzag groove 18. rug 1
The overhang portion 23 of No. 3 has an overhang length TW ₂₃ in approximately the tire cross-sectional direction A from both side ends 12c of the tread 12 toward the tread center 20, and this overhang length
TW ₂₃ is provided at least 20% of the tread width TW ₁₂ (51% on both sides in this embodiment). Overhang part 23
The overhang height h ₂₃ (5 mm in this example) of the third
As shown by the solid line in the figure, the depth of the lug groove 15 is H ₁₅
(w _23a ,
w _23b ) and the overhang width w ₂₃ (in this example, w _23a ,
w _23b (both 7.5 mm) is 20 to 20 of the total groove width W ₁₅ (30 mm in this example) including the overhang width w ₂₃ of the lug groove 15
70% (50% in this example). Other than the above, it is the same as a normal pneumatic radial tire. Next, the effect will be explained. In the present invention, the pneumatic tire 11 has a protrusion 23 on the lug side wall 13a of the lug 13 that protrudes into the lug groove 15 with a stepped cross section. (indicated by the dotted line), and the rolling tread 1
The amount of air compressed and expanded between 2 and the road surface has been significantly reduced. Tire noise is therefore significantly reduced. In addition, the increase or decrease in rigidity of the lugs 13 is small compared to conventional ones, and the lugs 13 are sufficient in terms of force transmission from the ground contact part and in terms of biting into the road surface on soft roads, so traction performance on various road surfaces is improved. can be secured sufficiently. Furthermore, the cross-sectional curvature of the groove bottom 15a is sufficiently large, so that bending fatigue of the rubber is small and no cracks occur. In the above-mentioned embodiment, a case has been described in which the overhanging portion 23 overhangs into the lug groove 15 in one step almost symmetrically in a stepped cross-section on both lug side walls 13a of the lug 13, but in the present invention. , Figure 4 a~
As in each of the other embodiments shown in FIG.
0 (Fig. 4a) or the two-stage overhang 32
(Fig. 4b) may also be provided. Furthermore, one or more stages of overhanging portions may be provided on both lug side walls 13a, that is, overhanging portions 34a and 34b (fourth
Figure c), or one is a one-stage overhang 36a.
, and the other is the two-stage overhang 36b (Fig. 4 d),
Furthermore, two-stage overhangs 38a and 3
8b (Fig. 4e) may also be provided. Next, test tires (tire size 31×
10.50R15) 3 types (1 type of example, 2 types of comparative example)
was prepared to confirm the effectiveness of the present invention. The test tire examples are the same as those shown in Figures 1-3 above. Comparative Example 1 is a conventional tire in which the cross-sectional shape of the lug groove is the lug groove ₂₈ shown by the dotted line in FIG.
Other configurations are the same as in the embodiment. Comparative Example 2 is a conventional tire in which the cross-sectional shape of the lug groove is the lug groove ₂₉ shown by the dashed line in FIG. It is the same as the example. These test tires were manufactured similarly. The test is based on the noise performance generated when driving on the test road,
We investigated traction performance when driving on soft roads. Each test tire was mounted on a test vehicle, driven under a predetermined load at a predetermined speed, and evaluated by a test driver's feeling test. The evaluation results are expressed as an index with the result of Comparative Example 1 (conventional tire) set as 100. The larger the index, the better. The evaluation results are shown in the table below.

【表】評価結果は、前表に示すように、実施例はトラ
クシヨン性能は比較例１（従来タイヤ）と同じで
あり、騒音性能は大幅に向上している。また、ラ
グ溝の溝底クラツク故障の発生もなかつた。（効果）以上説明したように、本考案によれば、軟弱路
を含む各種路面走行時のトラクシヨン性能は十分
に維持したまま走行時の騒音の発生を低減し、騒
音性能を大幅に向上できる。[Table] As shown in the above table, the evaluation results show that the traction performance of the example is the same as that of Comparative Example 1 (conventional tire), and the noise performance is significantly improved. Furthermore, there was no occurrence of bottom crack failures in the lug grooves. (Effects) As explained above, according to the present invention, noise generation during running can be reduced while traction performance is sufficiently maintained when running on various roads including soft roads, and noise performance can be significantly improved.

[Brief explanation of the drawing]

第１〜３図は本考案に係る空気入りタイヤの一
実施例を示す図であり、第１図はそのトレツド１
２の一部展開図、第２図は第１図のＣ矢視斜視
図、第３図は第１図の−矢視断面図および試
験タイヤの比較例１，２の溝断面形状図である。
第４図ａ〜ｅはそれぞれ本考案の空気入りタイヤ
の他の実施例の前述の第３図に対応する断面図で
ある。第５，６図は従来の空気入りタイヤを示す
図であり、第５図はそのトレツドの一部展開図、
第６図は第５図の−矢視断面図である。１１……空気入りタイヤ、１２……トレツド、
１２ａ……両側端面、１２ｂ……中央部、１２ｃ
……側端、１３……ラグ、１３ａ……側壁、１５
……ラグ溝、１７……ブロツク、１７ａ……側
壁、１８……ジクザグ溝、２０……トレツド中
央、２１……周方向溝、２３，２５，３０，３
２，３４ａ，３４ｂ，３６ａ，３６ｂ，３８ａ…
…張出部、H₁₅……ラグ溝の溝高さ、h₂₃……張出
部２３の張出し高さ、TW₁₂……トレツド幅、
TW₂₃……張出部２３の張出し長さ、W₁₅……ラ
グ溝の溝幅、W₂₃……張出部２３の張出し幅、Ａ
……タイヤ軸方向、Ｂ……タイヤ周方向。 1 to 3 are views showing an embodiment of the pneumatic tire according to the present invention, and FIG. 1 shows the tread 1 of the pneumatic tire.
2 is a perspective view taken in the direction of the C arrow in FIG. .
FIGS. 4a to 4e are sectional views corresponding to FIG. 3 of other embodiments of the pneumatic tire of the present invention, respectively. Figures 5 and 6 are diagrams showing a conventional pneumatic tire, and Figure 5 is a partially exploded view of its tread;
6 is a sectional view taken along the - arrow in FIG. 5. FIG. 11...pneumatic tire, 12...tread,
12a...Both end surfaces, 12b...Central part, 12c
...Side end, 13...Lug, 13a...Side wall, 15
...Lag groove, 17...Block, 17a...Side wall, 18...Zigzag groove, 20...Tread center, 21...Circumferential groove, 23, 25, 30, 3
2, 34a, 34b, 36a, 36b, 38a...
...Overhanging part, H ₁₅ ... Groove height of lug groove, h ₂₃ ... Overhanging height of overhanging part 23, TW ₁₂ ... Tread width,
TW ₂₃ ...Protrusion length of the protrusion 23, W ₁₅ ...Groove width of the lug groove, W ₂₃ ...Protrusion width of the protrusion 23, A
... Tire axial direction, B... Tire circumferential direction.

Claims

[Scope of utility model registration request]

A pneumatic tire that has lugs that form a pair in the tire axial direction at both ends of the tire tread and lug grooves adjacent to the lugs, and in which a large number of lugs and lug grooves are arranged alternately in the tire circumferential direction. , the lug has a protruding part on at least one lug side wall that protrudes into the lug groove with a stepped cross section, the protruding part is provided from both ends of the tread toward the center of the tread by 20% or more of the tread width; The projecting height h of the projecting portion is 20 to 50% of the depth H of the lug groove, and the projecting width w of the projecting portion is 20 to 70% of the total groove width W including the projecting width of the lug groove. A pneumatic tire characterized by: