JPS616008A - Pneumatic radial tire - Google Patents

Abstract

PURPOSE:To increase the inclination of the surface of a tread section to greatly enhance the anti-skid ability of a tire, by setting the height of radial ribs from the groove bottom to more than 4mm. and by making the heights thereof different at every other rib or every plural number rib. CONSTITUTION:A tread section 1 has radial narrow ribs 2, 3, and is stepped. Further, the heights of radial narrow ribs, even lowest one, are required to be more than 4mm. since, if they are more than 4mm., the rigidity of the tread section 1 as a whole would become insufficient so that the gripping force of the tire upon running on a curved road becomes insufficient to incurr instability in control.

Description

【発明の詳細な説明】 （産業上の利用分野） この発明は、スパイクピンを備えずに氷上走行に供する
ことができるトレッドを備えた空気入りラジアルタイヤ
に関する。DETAILED DESCRIPTION OF THE INVENTION (Field of Industrial Application) The present invention relates to a pneumatic radial tire with a tread that can be used for driving on ice without spike pins.

（従来の技術） 乗用車の普及により乗用車に装着される乗用車用空気入
りタイヤも耐久性重視の時代から、機能重視の時代に変
わりつつある。そこでタイヤの要求特性も耐スキツド性
、操縦安定性に代表される路面把握力と、振動、騒音に
代表される居住性、耐摩耗性及び燃費性に代表される経
済性が重視されてきている。しかしこれらの要求特性も
市場により重点付けが異なってくるが今日どの市場でも
重視されている特性は路面把握力（耐スリップ性）であ
りこの特性が不足すると湿温路面や冬期氷上路面では乾
燥路面に比べて著しく摩擦力が低い為スリップ事故等の
交通事故の原因となりやすいことは一般に良く知られて
いる。(Prior Art) With the spread of passenger cars, the pneumatic tires installed on passenger cars are also changing from an era where durability was emphasized to an era where functionality is emphasized. Therefore, the required characteristics of tires are becoming more focused on road gripping power as represented by skid resistance and steering stability, comfort as represented by vibration and noise, and economy as represented by wear resistance and fuel efficiency. . However, the emphasis placed on these required characteristics differs depending on the market, but the characteristic that is emphasized in all markets today is road grip (slip resistance), and if this characteristic is insufficient, it will be difficult to maintain control over humid roads or icy roads in winter. It is generally well known that because the frictional force is significantly lower than that of a motor vehicle, it is more likely to cause traffic accidents such as slip accidents.

従って例えば耐摩耗性を低下させても安全性の為に耐ス
リップ性を重視したタイヤを要望するユーザーが増加す
るなど市場ニーズも多様化してきている。Therefore, market needs are diversifying, with an increasing number of users demanding tires that place emphasis on slip resistance for safety even if wear resistance is reduced.

しめミし摩擦力の最も小さい氷上摩擦（氷上スキツド性
）の向上に関しては技術的限界があり、安心して氷上路
面上を運転出来ないのが現状である。冬期タイヤとして
は一般に今日市場で広く普及しているいわゆるスパイク
タイヤがあり、このスパイクタイヤであればなんとか氷
上路面を安心して走れるレベルにあると考えられている
。しかしこのスパイクタイヤは近年広く普及した反面ス
パイクビンによる路面の損傷問題や、損傷から発生する
路面材料の粉塵問題等大きな社会問題に発展しており、
海外においてもスパイクタイヤの全面使用禁止や、冬期
期間限定使用等の対策を実施しているが、日本ではまだ
海外に比べて冬期除雪、融雪の維持管理が徹底していな
い為スパイクタイヤを禁止すると耐スキツド性不足によ
る安全上の問題があり、一方では社会的公害、財政上の
問題との接点をどこにおくかでいっそう深刻な問題とな
っている。かかる情況のもとてスパイクを使用しないで
いわゆるノンスパイクタイヤで氷上性能をスパイクタイ
ヤ並みに向上させる必要が生じてきた。There are technical limits to improving ice friction (ice skidding), which has the smallest squeezing friction force, and currently it is not possible to drive on ice with peace of mind. Generally speaking, so-called spiked tires are widely used in the market today as winter tires, and these spiked tires are considered to be able to run safely on icy roads. However, although these spiked tires have become widespread in recent years, they have also developed into major social problems such as damage to road surfaces caused by spike bins and dust on road surface materials generated from damage.
Countermeasures such as a complete ban on the use of spiked tires and limited use of spiked tires in winter have been implemented in other countries, but in Japan, snow removal and snow melting maintenance in winter is not as thorough as in other countries, so spiked tires have been banned. There are safety problems due to the lack of skid resistance, and on the other hand, there are even more serious problems due to the point of contact with social pollution and financial problems. Under these circumstances, it has become necessary to use so-called non-spike tires, which do not use spikes, to improve on-ice performance to the same level as spiked tires.

そこで第２ａ図、第２ｂ図に示すトレッドを有するタイ
ヤが用いられた。第２ａ図はトレッドを正面から見た図
であり、第２ｂ図はトレッドを横（Ｂ−Ｂ）方向から見
た断面図である。なお、トレッドは第３図のごとくタイ
ヤに配置されている。第２ｂ図では、１がトレッド部で
あり、４が径方向狭巾リブであって、その高さは全て１
１ｍｍで同一である。Therefore, a tire having a tread shown in FIGS. 2a and 2b was used. FIG. 2a is a front view of the tread, and FIG. 2b is a cross-sectional view of the tread from the lateral (BB) direction. Note that the tread is arranged on the tire as shown in FIG. In Fig. 2b, 1 is a tread portion, 4 is a radial narrow rib, and the height thereof is 1
It is the same at 1 mm.

しかし、この第２ｂ図のトレッドのタイヤでは十分なグ
リップ性能は得られなかった。However, the tire with the tread shown in FIG. 2b did not provide sufficient grip performance.

（発明が解決しようとする問題点） 径方向リブを有する空気入りラジアルタイヤであって、
スパイクを打たない場合に十分な氷上グリップ性が得ら
れなかった。(Problems to be Solved by the Invention) A pneumatic radial tire having radial ribs,
When not using spikes, sufficient grip on the ice could not be obtained.

（問題点を解決するための手段） この発明は、タイヤのトレッドに狭幅の径方向リブを、
狭い配列で周方向に連続してタイヤ全周またはタイヤ周
方向に部分的に配置し、各々径方向リブの高さが溝底か
５４ｍｍ以上あり、かつ１段おきまたは数段おきに高低
差を有することを特徴とする空気入りラジアルタイヤか
らなる。(Means for solving the problem) This invention provides narrow radial ribs on the tread of a tire.
The ribs are arranged in a narrow array continuously in the circumferential direction all around the tire or partially in the tire circumferential direction, and each radial rib has a height of 54 mm or more above the groove bottom, and there is a difference in height at every other step or every few steps. A pneumatic radial tire characterized by:

（作　　　用） 即ち本発明のパターンの特徴は従来のトレッドパターン
が踏面部の溝底からの高さが略同−の高さであるのに対
して各パターンの間に表面（踏面）段差をつけることに
より、トレッド表面の倒れ込みを大きくしそれによって
路面部の接触面積が大きくなりかつ倒れ込み変形時のト
レッドゴムのヒステリシスロスが大きくなり耐スキツド
性が大幅に向上することを見い出した。(Function) In other words, the feature of the pattern of the present invention is that, whereas in conventional tread patterns, the heights of the tread portions from the groove bottom are approximately the same, there is a surface (tread) step between each pattern. It has been found that by attaching the tread rubber, the tread surface collapses larger, thereby increasing the contact area with the road surface, and increases the hysteresis loss of the tread rubber when the tread deforms due to the tread surface, thereby greatly improving skid resistance.

また、径方向狭巾リブの高さは低い方でも４ｍｍ以上あ
ることが必要である。これは４ｍｍ以下であるとトレッ
ド全体の剛性が不足してカーブ走行時のグリップ力（路
面把握力）が不足して操縦安定性に実用上問題が出てく
る為である。Further, the height of the narrow radial rib needs to be 4 mm or more at the lowest. This is because if it is less than 4 mm, the rigidity of the entire tread will be insufficient, resulting in insufficient grip (road surface grip) when driving on curves, which will cause practical problems in handling stability.

（実施例） ◆ 第１ａ図及び第１ｂ図は、この発明によるタイヤトレッ
ド部であり、第１ａ図はトレッドを正面から見た図であ
り、ＭＩ、ｌｂ図はトレッドを横（Ａ〜Ａ）方向から見
た断面図である。ｌがトレッド部であり２及び３が径方
向狭巾リブである。そして、リブ２の高さは１１ｍｍで
リブ３の高さは７．５ｍｍである。またリブ２とリブ３
の高低差は２〜５ｍｍの範囲が好ましい。何故なら高低
差が２ｍｍより小さいとリブ２の倒れ込みが小さくてグ
リップカガ小さくなり、５ｍｍより大きいと倒れ込みが
大き過ぎて操縦安定性が悪くなるからである。(Example) ◆ Figures 1a and 1b show the tire tread portion according to the present invention. Figure 1a is a view of the tread seen from the front, and MI and lb diagrams are views of the tread viewed from the side (A to A). It is a sectional view seen from the direction. 1 is a tread portion, and 2 and 3 are radial narrow ribs. The height of the rib 2 is 11 mm, and the height of the rib 3 is 7.5 mm. Also rib 2 and rib 3
The height difference is preferably in the range of 2 to 5 mm. This is because if the height difference is less than 2 mm, the ribs 2 will not fall down and the grip will be small, and if it is more than 5 mm, the fall will be too large and the steering stability will deteriorate.

第４〜第８図は別の実施例のトレッド断面図であり、そ
れは、第９図に示されているトレッド正ブの高さの１／
３〜３／２の範囲であり、リブの周方向ピッチは、高い
方のリブの高さの３倍よりは狭い範囲である。4 to 8 are tread cross-sectional views of another embodiment, which are 1/1/2 of the height of the tread front plate shown in FIG.
The circumferential pitch of the ribs is in the range of 3 to 3/2, and is narrower than 3 times the height of the taller rib.

（発明の効果） ここで第９図のトレッドパターンの両ショルダ一部５の
位置に第４図から第７図の試作パターンＡ、Ｂ、Ｃ，Ｄ
をつくった。又第８図（Ｅパターン）はコントロールパ
ターン（トレッド表面段差なし）である。試験タイヤは
サイズ１６５ＳＲ１３で２枚切離しスチールベルトを埋
設させたいわゆるスチールベルトラジアルタイヤである
。(Effects of the Invention) Here, the prototype patterns A, B, C, and D of FIGS. 4 to 7 are placed on both shoulder portions 5 of the tread pattern of FIG. 9.
I made it. Further, FIG. 8 (pattern E) is a control pattern (no step on the tread surface). The test tire was a so-called steel belt radial tire of size 165SR13, in which two separated steel belts were embedded.

スキッドテストはトレーラにてトラクションを測定して
コントロールパターンＥ対比の指数で示した、又テスト
条件としては氷上スキッドは凍結氷路面温度−３〜−２
°Ｃ１外気温−１〜０°Ｃで行ない、ウェットスキッド
は外気温５°Ｃで水深ｉｎｍの深さのウェットアスファ
ルト路面でテストした。試験結果を下記の表で示す。In the skid test, the traction was measured on a trailer and expressed as an index compared to control pattern E.The test conditions were as follows: The skid on ice had a frozen road surface temperature of -3 to -2.
The test was carried out at an outside temperature of -1 to 0°C, and the wet skid was tested on a wet asphalt road surface with an outside temperature of 5°C and a water depth of inch. The test results are shown in the table below.

結果は指数で示しており、指数は大きい程良い。The results are shown as an index, and the larger the index, the better.

【図面の簡単な説明】[Brief explanation of drawings]

第１図、第４図〜第７図及び第９図は、この発明による
トレッド、第２図、第８図は従来技術によるトレッド、
第３図は従来技術のトレッドを備えたタイヤ。 ｌ・・・トレッド、２，３．４・・・径方向狭幅リブ、
５・・・トレッドのシ層ルダ一部、６・・・タイヤ。 特許出願人　　株式会社　ブリヂストン第４図 第６図 第８図 第５図 第７図 第９図1, 4 to 7, and 9 are treads according to the present invention, and FIGS. 2 and 8 are treads according to the prior art,
Figure 3 shows a tire with a conventional tread. l...Tread, 2,3.4...Radial narrow rib,
5... Part of the tread layer, 6... Tire. Patent applicant: Bridgestone Co., Ltd.Figure 4Figure 6Figure 8Figure 5Figure 7Figure 9

Claims (2)

【特許請求の範囲】[Claims] （１）タイヤのトレッドに狭幅の径方向リブを、狭い配
列で周方向に連続してタイヤ全周またはタイヤ周方向に
部分的に配置し、各々径方向リブの高さが溝底から４ｍ
ｍ以上あり、かつ１段おきまたは数段おきに高低差を有
することを特徴とする空気入りラジアルタイヤ。(1) Narrow radial ribs are placed on the tread of the tire in a narrow array continuously in the circumferential direction all around the tire or partially in the tire circumferential direction, and the height of each radial rib is 4 m from the groove bottom.
A pneumatic radial tire having a height of at least m or more and having a height difference every other step or every few steps. （２）径方向リブの高低差が、２〜５ｍｍである（１）
記載の空気入りラジアルタイヤ。(2) The height difference between the radial ribs is 2 to 5 mm (1)
Pneumatic radial tires listed.