JP4528091B2 - Pneumatic tire - Google Patents

Pneumatic tire Download PDF

Info

Publication number
JP4528091B2
JP4528091B2 JP2004315917A JP2004315917A JP4528091B2 JP 4528091 B2 JP4528091 B2 JP 4528091B2 JP 2004315917 A JP2004315917 A JP 2004315917A JP 2004315917 A JP2004315917 A JP 2004315917A JP 4528091 B2 JP4528091 B2 JP 4528091B2
Authority
JP
Japan
Prior art keywords
groove
circumferential
tire
groove bottom
raised portion
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Expired - Fee Related
Application number
JP2004315917A
Other languages
Japanese (ja)
Other versions
JP2006123786A (en
Inventor
香緒理 成瀬
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
Bridgestone Corp
Original Assignee
Bridgestone Corp
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by Bridgestone Corp filed Critical Bridgestone Corp
Priority to JP2004315917A priority Critical patent/JP4528091B2/en
Publication of JP2006123786A publication Critical patent/JP2006123786A/en
Application granted granted Critical
Publication of JP4528091B2 publication Critical patent/JP4528091B2/en
Expired - Fee Related legal-status Critical Current
Anticipated expiration legal-status Critical

Links

Images

Classifications

    • 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
    • B60C11/13—Tread patterns characterised by the groove cross-section, e.g. for buttressing or preventing stone-trapping
    • B60C11/1376—Three dimensional block surfaces departing from the enveloping tread contour
    • B60C11/1384—Three dimensional block surfaces departing from the enveloping tread contour with chamfered block corners
    • 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
    • B60C11/04—Tread patterns in which the raised area of the pattern consists only of continuous circumferential ribs, e.g. zig-zag
    • B60C11/042—Tread patterns in which the raised area of the pattern consists only of continuous circumferential ribs, e.g. zig-zag further characterised by the groove cross-section
    • B60C11/047—Tread patterns in which the raised area of the pattern consists only of continuous circumferential ribs, e.g. zig-zag further characterised by the groove cross-section the groove bottom comprising stone trapping protection elements, e.g. ribs

Landscapes

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

Description

この発明は、トレッド部に、タイヤ周方向に沿って延びる複数本の周方向溝と、該周方向溝の少なくとも１本と連通する複数本の横溝とを配設し、該周方向溝、両トレッド端及び該横溝によってトレッド部を多数個のブロック陸部に区画形成した、いわゆるブロックパターンを有する空気入りタイヤに関し、特にかかる空気入りタイヤのブロック陸部に発生する偏摩耗を、タイヤ摩耗初期から摩耗終期にわたって有効に抑制する。   In the tread portion, a plurality of circumferential grooves extending along the tire circumferential direction and a plurality of lateral grooves communicating with at least one of the circumferential grooves are disposed on the tread portion. With respect to a pneumatic tire having a so-called block pattern in which a tread portion is partitioned into a plurality of block land portions by the tread end and the lateral groove, in particular, uneven wear occurring in the block land portion of such a pneumatic tire is detected from the initial stage of tire wear. Effective control over the end of wear.

トレッド部に、周方向溝とこれに連通する横溝とを配設してブロックパターンを区画形成した空気入りタイヤ、特にトラックやバス等に用いられる重荷重用空気入りタイヤは、ブロック陸部に偏摩耗を生じやすい。かかる偏摩耗は、タイヤの外観を悪化させるのみならず、グリップ性能にも悪影響を与える。   Pneumatic tires with a block pattern formed by arranging circumferential grooves and lateral grooves communicating with them in the tread, especially heavy duty pneumatic tires used for trucks, buses, etc., have uneven wear on the block land It is easy to produce. Such uneven wear not only deteriorates the appearance of the tire but also adversely affects grip performance.

かかる偏摩耗を抑制するため、例えば特許文献１には、ブロックの外表面を、幅方向外側の周方向曲率半径がタイヤ赤道面側の周方向曲率半径よりも小さく、かつ幅方向外側の端部におけるタイヤ半径よりも小さく形成した低位部を有する空気入りタイヤが記載されている。かかるタイヤは、特にヒールアンドトウ摩耗の抑制に有効である。   In order to suppress such uneven wear, for example, Patent Document 1 discloses that the outer surface of the block has a circumferential curvature radius on the outer side in the width direction smaller than a circumferential curvature radius on the tire equatorial plane side and an end portion on the outer side in the width direction. A pneumatic tire having a lower portion formed smaller than the tire radius is described. Such a tire is particularly effective in suppressing heel and toe wear.

また、特許文献２には、ブロック陸部に、その内陸部から端縁又は角部に向かって陸部高さが漸減する低位部を設け、周方向溝に、所定の静的負荷条件下で路面とすべり接触する突起を設けた空気入りタイヤが記載されている。かかるタイヤは、特にリバーウエアとヒールアンドトウ摩耗を抑制するとともに、周方向溝での石噛みを防止することができる。   Patent Document 2 also provides a block land portion having a lower portion where the land portion height gradually decreases from the inland portion toward the edge or corner, and the circumferential groove has a predetermined static load condition. A pneumatic tire provided with a protrusion that is in sliding contact with a road surface is described. Such a tire can suppress river wear and heel and toe wear, and can prevent stone biting in a circumferential groove.

特許文献３には、周方向溝に、所定の静的負荷条件下で路面とすべり接触する突起を設け、ブロック陸部に、前記周方向溝とは反対側に位置する角部に向かって陸部高さが漸減する低位部を設けた空気入りタイヤが記載されている。かかるタイヤは、リバーウエアとヒールアンドトウ摩耗の双方の発生を高いレベルで抑制することができる。   In Patent Document 3, a protrusion that slides in contact with the road surface under a predetermined static load condition is provided in the circumferential groove, and the land on the block land portion is directed toward the corner located on the side opposite to the circumferential groove. A pneumatic tire provided with a lower portion where the height of the portion gradually decreases is described. Such a tire can suppress the occurrence of both river wear and heel and toe wear at a high level.

特許文献４には、ブロック陸部のトレッド端側で、トレッド周方向両端の二隅部に、ブロック高さが、それらの隅部の突端に向かって次第に減少する面取り表面を設けた空気入りタイヤが記載されている。かかるタイヤは、発生騒音の増加なしに耐偏摩耗性能を向上させることができる。   Patent Document 4 discloses a pneumatic tire provided with chamfered surfaces in which the block height gradually decreases toward the projecting ends of the corners at the two corners at both ends in the tread circumferential direction on the tread end side of the block land portion. Is described. Such tires can improve uneven wear resistance performance without an increase in generated noise.

特開平７−３０４３０９号公報JP-A-7-304309 特開平９−２４０２２０号公報JP-A-9-240220 特開平１０−８６６１０号公報Japanese Patent Laid-Open No. 10-86610 特開平１１−４８７１９号公報JP 11-48719 A

しかし、これら特許文献１〜４に記載されたタイヤは、摩耗初期こそ有効に偏摩耗の発生を抑制できるが、摩耗が進むことによって、低位部と他の部分との陸部高さの差がなくなったり、周方向溝内の突起とブロック陸部の高さの差がなくなり突起がすべり接触しなくなったり、面取り表面が減少すると、ブロック陸部に偏摩耗が発生するおそれがあった。   However, the tires described in Patent Documents 1 to 4 can effectively suppress the occurrence of uneven wear at the initial stage of wear. However, as wear progresses, the difference in land height between the lower portion and other portions is increased. If the height difference between the protrusion in the circumferential groove and the block land portion disappears and the protrusion does not come into sliding contact or the chamfered surface decreases, there is a risk that uneven wear occurs in the block land portion.

したがって、この発明の目的は、周方向溝に設けた溝底***部及びブロック陸部の形状の適正化を図ることにより、ブロック陸部に発生する偏摩耗を、タイヤ摩耗初期から摩耗終期にわたって有効に抑制することのできる空気入りタイヤを提供することにある。   Therefore, the object of the present invention is to prevent uneven wear generated in the block land portion from the initial stage of tire wear to the end of wear by optimizing the shape of the groove bottom raised portion and the block land portion provided in the circumferential groove. An object of the present invention is to provide a pneumatic tire that can be suppressed.

上記の目的を達成するため、この発明は、トレッド部に、タイヤ周方向に沿って延びる複数本の周方向溝と、該周方向溝の少なくとも１本と連通する複数本の横溝とを配設し、該周方向溝、両トレッド端及び該横溝によってトレッド部を多数個のブロック陸部に区画形成してなる空気入りタイヤにおいて、少なくとも１本の周方向溝に、溝深さが他の部分よりも浅く、かつタイヤ周方向に沿って延びる溝底***部を設け、該溝底***部を設けた周方向溝に隣接するブロック陸部は、その内陸部分から少なくとも一つの端部又は角部に向かって陸部高さが漸減する曲面状の頂面を有し、前記溝底***部は、所定の静的負荷条件にて、タイヤ摩耗初期にはそのタイヤ径方向最外端が路面と非接触状態にあり、タイヤ摩耗中期以降にはそのタイヤ径方向最外端が路面と接触状態にある溝深さを有することを特徴とする空気入りタイヤである。   In order to achieve the above object, according to the present invention, a plurality of circumferential grooves extending along a tire circumferential direction and a plurality of lateral grooves communicating with at least one of the circumferential grooves are disposed in the tread portion. In the pneumatic tire formed by partitioning the tread portion into a plurality of block land portions by the circumferential groove, both tread ends, and the lateral groove, the groove depth is another portion in at least one circumferential groove. A groove bottom ridge that is shallower and extends along the tire circumferential direction, and the block land portion adjacent to the circumferential groove provided with the groove bottom ridge is at least one end or corner from its inland portion The groove-bottom ridge has an outermost end in the tire radial direction that is a road surface at the initial stage of tire wear under a predetermined static load condition. The tire diameter is in a non-contact state and after the middle of tire wear Direction outermost end is pneumatic tire characterized by having a groove depth which is in contact with the road surface.

ここで「タイヤ周方向に沿って延びる」とは、溝又は溝底***部全体としての延在方向がタイヤ周方向であることをいうものとし、ジグザグ状又は波状の延在形状を有するものであってもよい。また、「所定の静的負荷条件」とは、ＪＡＴＭＡに規定された静的負荷半径測定条件、すなわちタイヤを適用リムに装着し、最大負荷能力に対応する空気圧（乗用車用タイヤの場合には１８０ｋＰａ）を適用し、最大負荷能力（乗用車用タイヤの場合には最大負荷能力の８８％）に相当する質量を負荷した条件をいうものとする。さらに、タイヤが使用寿命に達するまでにブロック陸部が摩耗する量をブロック最大摩耗量として、「タイヤ摩耗初期」とは、ブロック陸部の摩耗量がブロック最大摩耗量の０〜４０％の範囲にある状態をいうものとし、「タイヤ摩耗中期以降」とは、ブロック陸部の摩耗量がブロック最大摩耗量の４０〜１００％の範囲にある状態をいうものとする。   Here, “extending along the tire circumferential direction” means that the extending direction of the entire groove or groove bottom raised portion is the tire circumferential direction, and has a zigzag or wavy extending shape. There may be. The “predetermined static load condition” is a static load radius measurement condition defined by JATMA, that is, a pneumatic pressure corresponding to the maximum load capacity when a tire is mounted on an applicable rim (180 kPa in the case of a passenger car tire). ) And a condition under which a mass corresponding to the maximum load capacity (88% of the maximum load capacity in the case of a passenger car tire) is loaded. Furthermore, the amount of wear of the block land portion before the tire reaches the service life is defined as the block maximum wear amount, and “the tire wear initial stage” means that the wear amount of the block land portion is in the range of 0 to 40% of the block maximum wear amount. The term “after mid-tire wear” refers to a state where the wear amount of the block land portion is in the range of 40 to 100% of the block maximum wear amount.

また、溝底***部での溝深さは、これを設けた周方向溝に開口する横溝の溝深さより深いこと、特には２ｍｍ以上深いことが好ましい。ここで「溝深さ」とは、トレッド部踏面と溝底との間をタイヤ径方向に沿って測定した距離をいうものとする。   Moreover, it is preferable that the groove depth at the groove bottom raised portion is deeper than the groove depth of the lateral groove opened to the circumferential groove provided with the groove, particularly 2 mm or more. Here, the “groove depth” refers to a distance measured between the tread surface and the groove bottom along the tire radial direction.

さらに、溝底***部での溝深さは、５〜７ｍｍの範囲にあることが好ましい。   Furthermore, it is preferable that the groove depth in the groove bottom raised portion is in the range of 5 to 7 mm.

さらにまた、溝底***部での溝深さは、これを設けた周方向溝に隣接するブロック陸部の端部での陸部高さの３０〜４５％の範囲にあることが好ましい。   Furthermore, it is preferable that the groove depth in the groove bottom raised portion is in the range of 30 to 45% of the land portion height at the end of the block land portion adjacent to the circumferential groove provided with the groove.

加えて、溝底***部を設けた周方向溝に隣接する横溝の溝深さは３〜５ｍｍの範囲にあることが好ましい。   In addition, the groove depth of the lateral groove adjacent to the circumferential groove provided with the groove bottom raised portion is preferably in the range of 3 to 5 mm.

加えてまた、タイヤ幅方向で最も外側に位置する周方向溝に溝底***部を設けてなることが好ましい。   In addition, it is preferable that a groove bottom raised portion is provided in a circumferential groove located on the outermost side in the tire width direction.

この発明によれば、空気入りタイヤの周方向溝に設けた溝底***部及びブロック陸部の形状の適正化を図ることにより、ブロック陸部に発生する偏摩耗を、タイヤ摩耗初期から摩耗終期にわたって有効に抑制することが可能となる。   According to the present invention, by optimizing the shape of the groove bottom raised portion and the block land portion provided in the circumferential groove of the pneumatic tire, uneven wear occurring in the block land portion is prevented from the tire wear initial stage to the wear end stage. It is possible to effectively suppress over the range.

以下、図面を参照しつつこの発明の実施の形態を説明する。図１は、この発明に従う代表的な空気入りタイヤ（以下「タイヤ」という。）のトレッド部の一部を展開して示しており、図２（ａ）は、図１のＩ−Ｉ線上の断面を示しており、図２（ｂ）は、図１のＩＩ−ＩＩ線上の断面を示している。また、図３は、図１に示すブロック陸部５ｂの１個を抜き出して周方向溝側から見たときの斜視図である。   Hereinafter, embodiments of the present invention will be described with reference to the drawings. FIG. 1 shows a developed part of a tread portion of a typical pneumatic tire (hereinafter referred to as “tire”) according to the present invention. FIG. The cross section is shown, FIG.2 (b) has shown the cross section on the II-II line | wire of FIG. FIG. 3 is a perspective view when one of the block land portions 5b shown in FIG. 1 is extracted and viewed from the circumferential groove side.

図１に示すタイヤは、トレッド部１に、タイヤ周方向に沿って延びる複数本の周方向溝、図１では４本の周方向溝２ａ、２ｂ、２ｃ、２ｄと、周方向溝２ａ〜２ｄの少なくとも１本と連通する複数本の横溝３ａ、３ｂ、３ｃ、３ｄ、３ｅとを配設する。なお、横溝３ａ〜３ｅは、３ａ及び３ｅのように略タイヤ幅方向に延在していてもよく、３ｂ及び３ｄのようにタイヤ幅方向に対して傾斜して延在していてもよく、３ｃのようにクランク状であってもよい。トレッド部１は、周方向溝２ａ〜２ｄ、両トレッド端４ａ、４ｂ及び横溝３ａ〜３ｅによって多数個のブロック陸部５ａ、５ｂ、５ｃ、５ｄ、５ｅに区画形成される。   The tire shown in FIG. 1 has a plurality of circumferential grooves extending in the tire circumferential direction in the tread portion 1, in FIG. 1, four circumferential grooves 2a, 2b, 2c, and 2d, and circumferential grooves 2a to 2d. A plurality of lateral grooves 3a, 3b, 3c, 3d, and 3e communicating with at least one of these are disposed. The lateral grooves 3a to 3e may extend substantially in the tire width direction as in 3a and 3e, or may extend incline with respect to the tire width direction as in 3b and 3d. It may be crank-shaped as in 3c. The tread portion 1 is partitioned into a large number of block land portions 5a, 5b, 5c, 5d, and 5e by circumferential grooves 2a to 2d, both tread ends 4a and 4b, and lateral grooves 3a to 3e.

そして、この発明の構成上の主な特徴は次のような点にある。すなわち、少なくとも１本の周方向溝、図１では２本の周方向溝２ａ及び２ｄに、溝深さｄ１が他の部分の溝深さｄ２よりも浅く、かつタイヤ周方向に沿って延びる溝底***部６を設ける。溝底***部６を設けた周方向溝２ａ及び２ｄに隣接するブロック陸部５ａと５ｂ、５ｄと５ｅは、頂面の少なくとも一部をドーム状とする。ここでドーム状の陸部とは、ブロック陸部５ｂを例に取ると、その内陸部分７から、横溝３ｂ、３ｂによって形成された端部８ａ、８ｂ、又は横溝３ｂ、３ｂと周方向溝２ａ、２ｂとによって形成された角部９ａ、９ｂ、９ｃ、９ｄのうちのうち少なくとも一つに向かって陸部高さｈが漸減する曲面状の頂面を有している陸部のことをいう。すなわち、図３（ａ）に示すように、内陸部分７から少なくとも一つの端部（図３（ａ）では両方の端部８ａ、８ｂ）に向かって陸部高さｈが漸減する陸部、図３（ｂ）及び（ｃ）に示すように、内陸部分７から少なくとも一つの角部（図３（ｂ）では角部９ａ、図３（ｃ）では角部９ａ及び９ｃに）向かって陸部高さｈが漸減する陸部、又は図３（ｄ）に示すように、内陸部分７から一つの端部（図３（ｄ）では端部８ｂ）と少なくとも一つの角部（図３（ｄ）では角部９ａ）に向かって陸部高さｈが漸減する陸部等が含まれる。そして、溝底***部６の溝深さｄ１を、所定の静的負荷条件にて、タイヤ摩耗初期にはそのタイヤ径方向最外端、図２ではその頂面１０が、路面と非接触状態にあり、タイヤ摩耗中期以降にはそのタイヤ径方向最外端が路面と接触状態にあるように設定する。 The main features of the configuration of the present invention are as follows. That is, at least one circumferential groove, into two circumferential grooves 2a and 2d in Figure 1, groove depth d 1 is shallower than the groove depth d 2 of the other part, and along the tire circumferential direction An extending groove bottom ridge 6 is provided. The block land portions 5a and 5b, 5d and 5e adjacent to the circumferential grooves 2a and 2d provided with the groove bottom raised portion 6 have at least a part of the top surface in a dome shape. Here, when the block land portion 5b is taken as an example of the dome-shaped land portion, the end portions 8a and 8b formed by the lateral grooves 3b and 3b from the inland portion 7 or the lateral grooves 3b and 3b and the circumferential groove 2a 2b and a land portion having a curved top surface in which the land height h gradually decreases toward at least one of the corner portions 9a, 9b, 9c, 9d. . That is, as shown in FIG. 3 (a), the land portion where the land height h gradually decreases from the inland portion 7 toward at least one end (both ends 8a and 8b in FIG. 3 (a)), As shown in FIGS. 3 (b) and 3 (c), land from the inland portion 7 toward at least one corner (corner 9a in FIG. 3 (b) and corners 9a and 9c in FIG. 3 (c)). The land portion where the height h gradually decreases, or, as shown in FIG. 3 (d), from the inland portion 7 to one end (the end 8b in FIG. 3 (d)) and at least one corner (FIG. 3 ( d) includes a land portion where the land height h gradually decreases toward the corner portion 9a). Then, the groove depth d 1 of the groove bottom raised portion 6 is set to the outermost end in the tire radial direction at the initial stage of tire wear under a predetermined static load condition, and the top surface 10 in FIG. 2 is not in contact with the road surface. In the state, the outermost end in the tire radial direction is set in contact with the road surface after the middle stage of tire wear.

前述のように、ブロック陸部に生じる偏摩耗を抑制する手段としては、ブロック陸部頂面をドーム状にするか、ブロック陸部に隣接する周方向溝内に溝底***部を設けることが一般的であった。ブロック陸部をドーム状としたタイヤでは、偏摩耗の発生しやすい部位を、予め陸部高さの低い低位部として形成することで偏摩耗を予防している。また、溝底***部を有するタイヤでは、溝底***部での溝深さを微小にして溝底***部を路面とすべり接触させることで、ブロック陸部の摩耗を促進する力を溝底***部に集中させることで偏摩耗を予防している。しかし、これらいずれのタイヤにおいても、摩耗初期には所期した偏摩耗防止効果が得られるものの、摩耗中期以降には偏摩耗防止効果が十分とは言えない場合があった。これは、タイヤが摩耗し、ブロック陸部の陸部高さが低下するにつれて、ドーム状のブロック陸部を有するタイヤでは、低位部と他の部分との陸部高さの差がなくなる結果、低位部に偏摩耗が生じやすいためであり、溝底***部を有するタイヤでは、溝底***部の頂面とブロック陸部の頂面とが略一致し、路面と溝底***部がすべり接触ではなく通常の接触をする結果、摩耗を促進する力を集中的に負担することができなくなるためである。   As described above, as means for suppressing uneven wear occurring in the block land portion, the top surface of the block land portion is formed in a dome shape, or a groove bottom raised portion is provided in a circumferential groove adjacent to the block land portion. It was general. In a tire having a block land portion having a dome shape, uneven wear is prevented by forming in advance a portion where uneven wear is likely to occur as a lower portion having a low land portion height. Also, in tires with groove bottom ridges, the groove bottom ridges have a force that promotes wear of the block land by making the groove depth at the groove bottom ridges small and sliding the groove bottom ridges against the road surface. Uneven wear is prevented by concentrating on the part. However, in any of these tires, although the expected uneven wear prevention effect can be obtained in the early stage of wear, the uneven wear preventive effect may not be sufficient after the middle wear stage. This is because, as the tire wears and the land height of the block land portion decreases, in the tire having the dome-shaped block land portion, there is no difference in the land height between the lower portion and the other portions, This is because uneven wear is likely to occur in the lower part, and in tires with groove bottom ridges, the top surface of the groove bottom ridge and the top surface of the block land part substantially coincide, and the road surface and the groove bottom ridge are in sliding contact. This is because, as a result of normal contact, the force that promotes wear cannot be concentrated.

これに対し、この発明に従うタイヤは、摩耗段階に応じて異なる偏摩耗防止手段を使い分けることによって、タイヤが摩耗寿命に達するまで効果的に偏摩耗を防止している。具体的には、ブロック陸部の頂面をドーム状の輪郭形状に形成するとともに、溝底***部を摩耗中期以降にしか路面と接地しないように形成することで、タイヤの摩耗初期にはドーム状のブロック陸部のみが偏摩耗防止手段として作用し、一方、ブロック陸部が摩耗し、その頂面の輪郭形状がフラットに近づく摩耗中期以降には、周方向溝内に設けられた溝底***部が路面とすべり接触することで偏摩耗防止手段として作用する。これによって、従来のタイヤでは偏摩耗抑制効果が低下していたタイヤの摩耗中期以降でも、高い偏摩耗防止効果を維持することができるのである。   On the other hand, the tire according to the present invention effectively prevents uneven wear until the tire reaches its wear life by using different uneven wear prevention means depending on the wear stage. Specifically, the top surface of the block land portion is formed in a dome-like contour shape, and the groove bottom raised portion is formed so as to come into contact with the road surface only after the middle stage of wear. Only the block-shaped block land portion acts as a means for preventing uneven wear, while the block land portion is worn and the bottom of the groove provided in the circumferential groove is in the middle of the wear where the contour shape of the top surface approaches flat. When the raised portion is in sliding contact with the road surface, it acts as a means for preventing uneven wear. As a result, a high uneven wear prevention effect can be maintained even after the middle stage of wear of the tire, where the effect of suppressing uneven wear has been reduced in the conventional tire.

さらに、従来の溝底***部を有するタイヤでは、溝底***部と路面が常に接触しているため、タイヤ幅方向内側に存在していた水の、横溝を介してトレッド端に移動する流れが溝底***部によって阻害されるため、排水性の低下が懸念されるが、この発明に従うタイヤでは、摩耗初期の段階には溝底***部と路面との間には間隙が存在するため、水の流れを阻害することがなく、排水性が低下することもない。   Furthermore, in a tire having a conventional groove bottom raised portion, the groove bottom raised portion and the road surface are always in contact with each other, so that there is a flow of water moving to the tread end through the lateral groove, which was present on the inner side in the tire width direction. There is a concern about the deterioration of drainage because it is hindered by the groove bottom bulge, but in the tire according to the present invention, there is a gap between the groove bottom bulge and the road surface at the initial stage of wear. The flow of water is not hindered, and the drainage performance is not deteriorated.

また、溝底***部６での溝深さｄ１は、これを設けた周方向溝２ａ、２ｄに開口する横溝３ａ及び３ｂ、３ｄ及び３ｅの溝深さｄ３より深いことが好ましい。これによれば、溝深さｄ３が浅くなり、タイヤ周方向でこれに隣接するブロック陸部３ｂ、３ｄの陸部剛性が上がる結果、偏摩耗抑制効果が一層向上するからであり、また、溝底***部６が路面と接触したときに、溝底***部６によってトレッド端に向かう水の流れが阻害されるのを防げるからである。より好ましくは、溝深さｄ１を溝深さｄ３よりも２ｍｍ以上深くする。 The groove depth d 1 at the groove bottom ridges 6, the circumferential grooves 2a provided this lateral groove 3a and 3b open to 2d, it is preferable deeper than 3d and 3e groove depth d 3 of the. According to this, the shallower the groove depth d 3, the block land portion 3b adjacent thereto in the tire circumferential direction, a result of the land portion rigidity of the 3d increases, is because the effect of inhibiting uneven wear is further improved, Further, This is because when the groove bottom ridge 6 comes into contact with the road surface, the groove bottom ridge 6 can prevent the flow of water toward the tread end from being obstructed. More preferably, deeper than 2mm than the groove depth d 3 of the groove depth d 1.

さらに、溝底***部６での溝深さｄ１を５〜７ｍｍの範囲とすることが好ましい。溝深さｄ１が５ｍｍ未満の場合にはタイヤの摩耗初期から溝底***部６が路面と接触するおそれがあるからであり、７ｍｍを超えると、ドーム状のブロック陸部による偏摩耗抑制効果が低下した後も、かなりの走行距離にわたって溝底***部６が路面と非接触状態になり、偏摩耗が発生するおそれがあるからである。 Furthermore, it is preferable that the groove depth d1 at the groove bottom raised portion 6 is in the range of 5 to 7 mm. This is because if the groove depth d 1 is less than 5 mm, the groove bottom raised portion 6 may come into contact with the road surface from the beginning of wear of the tire. If the groove depth d 1 exceeds 7 mm, the uneven wear suppression effect by the dome-shaped block land portion is likely. This is because the groove-bottom ridge 6 is not in contact with the road surface over a considerable travel distance even after the reduction of the travel distance, and uneven wear may occur.

さらにまた、溝底***部６での溝深さｄ１は、これを設けた周方向溝２ａ、２ｄに隣接するブロック陸部５ａ及び５ｂ、５ｄ及び５ｅの端部８ａ、８ｂでの陸部高さｈの３０〜４５％の範囲にあることが好ましい。ドーム状のブロック陸部５ａ、５ｂ、５ｄ、５ｅによる偏摩耗抑制効果が低下すると同時に溝底***部６が路面と接触状態になるようにするためである。 Furthermore, the groove depth d 1 at the groove bottom ridges 6, the circumferential grooves 2a provided this, the block land portions 5a and 5b adjacent to 2d, 5d and 5e of the end portion 8a, the land portion at the 8b It is preferable to be in the range of 30 to 45% of the height h. This is because the effect of suppressing uneven wear by the dome-shaped block land portions 5a, 5b, 5d, and 5e is reduced, and at the same time, the groove bottom raised portion 6 is brought into contact with the road surface.

加えて、溝底***部６を設けた周方向溝２ａ、２ｄに隣接する横溝３ａ及び３ｂ、３ｄ及び３ｅの溝深さｄ３は３〜５ｍｍの範囲にあることが好ましい。横溝３ａ、３ｂ、３ｄ、３ｅの溝深さｄ３が３ｍｍ未満の場合にはこれを介してタイヤ幅方向外方に排出できる水量が低下し、排水性が損なわれるおそれがあるからであり、５ｍｍを超える場合にはこれに隣接するブロック陸部５ａ及び５ｂ、５ｄ及び５ｅのブロック剛性が低下して偏摩耗が発生するおそれがあるからである。 In addition, the groove depth d3 of the lateral grooves 3a and 3b, 3d and 3e adjacent to the circumferential grooves 2a and 2d provided with the groove bottom raised portion 6 is preferably in the range of 3 to 5 mm. If the groove depth d3 of the lateral grooves 3a, 3b, 3d, and 3e is less than 3 mm, the amount of water that can be discharged outwardly in the tire width direction is reduced through this, and the drainage performance may be impaired. This is because if it exceeds 5 mm, the block land portions 5a and 5b, 5d and 5e adjacent to the block land portion may have a reduced block rigidity and may cause uneven wear.

溝底***部６は、図１に示すように、タイヤ幅方向で最も外側に位置する周方向溝２ａ、２ｄに設けることが好ましい。タイヤ幅方向外側に位置するブロック陸部ほど、偏摩耗が発生しやすいからである。   As shown in FIG. 1, the groove bottom raised portion 6 is preferably provided in the circumferential grooves 2 a and 2 d located on the outermost side in the tire width direction. This is because uneven wear tends to occur in the block land portion located on the outer side in the tire width direction.

なお、上述したところは、この発明の実施形態の一部を示したにすぎず、請求の範囲において種々の変更を加えることができる。例えば、図１に示すように、ブロック陸部５ａ〜５ｅに、短サイプ１１を設けることで、偏摩耗抑制効果を一層高めることができ、中央域に位置するブロック陸部５ｃに細溝１２を設けることで排水性を高めることもできるが、これらは必須ではない。また、図１では周方向溝が４本の態様を示したが、図４に示すように周方向溝が３本であってもよく、図示は省略するが、周方向溝が５本以上であってもよい。さらに、ドーム状の陸部は、図３（ａ）に示すように、頂面全体が曲面状であってもよいが、図３（ｂ）〜（ｄ）に示すように、頂面の一部のみが曲面状であってもよい。   In addition, the place mentioned above only showed a part of embodiment of this invention, and can add a various change in a claim. For example, as shown in FIG. 1, by providing the short sipe 11 in the block land portions 5a to 5e, the effect of suppressing uneven wear can be further enhanced, and the narrow groove 12 is provided in the block land portion 5c located in the central region. Although it can improve drainage by providing, these are not essential. In addition, although FIG. 1 shows an aspect with four circumferential grooves, there may be three circumferential grooves as shown in FIG. 4, although illustration is omitted, there are five or more circumferential grooves. There may be. Further, as shown in FIG. 3A, the dome-shaped land portion may have a curved surface as a whole, but as shown in FIGS. 3B to 3D, Only the part may be curved.

次に、この発明に従う空気入りタイヤを試作し性能評価を行ったので、以下に説明する。   Next, a pneumatic tire according to the present invention was prototyped and performance evaluation was performed, which will be described below.

実施例１及び２のタイヤは、タイヤサイズが１１Ｒ２２．５のトラック用ラジアルタイヤであり、図４に示すトレッドパターンを有し、ブロック陸部がいずれもドーム状の頂面輪郭形状を有し、表１に示す諸元を有する。   The tires of Examples 1 and 2 are radial tires for trucks having a tire size of 11R22.5, have the tread pattern shown in FIG. 4, and each of the block land portions has a dome-shaped top surface contour shape, It has the specifications shown in Table 1.

比較のため、タイヤサイズが実施例１及び２と同じであり、図４に示すものと同様のトレッドパターンを有するものの、摩耗初期から溝底***部が路面と接触状態にあり、表１に示すタイヤ（従来例）についても併せて試作した。   For comparison, the tire size is the same as in Examples 1 and 2 and has a tread pattern similar to that shown in FIG. 4, but the groove bottom raised portion is in contact with the road surface from the beginning of wear, and is shown in Table 1. A tire (conventional example) was also prototyped.

前記各供試タイヤをサイズ７．５０×２２．５のリムに取り付けてタイヤ車輪とし、このタイヤ車輪とテスト車両に装着し、空気圧：９００ｋＰａ（相対圧）を適用して、次の各試験を行った。   Each of the test tires is attached to a rim of size 7.50 × 22.5 to form a tire wheel. The tire wheel and a test vehicle are attached to the tire, and an air pressure of 900 kPa (relative pressure) is applied. went.

（ウエット路面でのトラクション性）
空車相当のタイヤ荷重を適用し、水深２ｍｍのウエット路面のテストコースを用い、静止状態から加速して１５ｍの距離を走行するのに要した時間を測定して、この測定値によりウエット路面でのトラクション性を評価した。その評価結果を表１に示す。 (Treatment on wet road surface)
Applying a tire load equivalent to an empty vehicle, using a wet road surface test course with a water depth of 2 mm, measure the time required to travel a distance of 15 m by accelerating from a stationary state. Traction was evaluated. The evaluation results are shown in Table 1.

（耐偏摩耗性）
ＪＡＴＭＡに定める最大負荷能力相当のタイヤ荷重を適用し、高速道路を主体に公道を５０，０００ｋｍ走行した後、トレッド部を目視点検し、ブロック陸部に発生した偏摩耗の容積を測定して、この測定値により耐偏摩耗性を評価した。その評価結果を表１に示す。 (Uneven wear resistance)
Apply tire load equivalent to the maximum load capacity specified in JATMA, drive 50,000km on the highway mainly on the highway, visually inspect the tread part, measure the volume of uneven wear generated in the block land part, The uneven wear resistance was evaluated based on this measured value. The evaluation results are shown in Table 1.

Figure 0004528091
Figure 0004528091

なお、表１中の評価結果は、従来例のタイヤの評価結果を１００としたときの指数比で示しており、ウエット路面でのトラクション性は数値が大きいほど性能が優れており、耐偏摩耗性については数値が小さいほど性能が優れている。   The evaluation results in Table 1 are shown as an index ratio when the evaluation result of the tire of the conventional example is set to 100. The larger the numerical value, the better the traction on the wet road surface. The smaller the numerical value, the better the performance.

表１に示す結果から、実施例１及び２のタイヤは、従来例のタイヤに比べて摩耗初期の排水性に優れている上、耐偏摩耗性にも優れていることが分かる。   From the results shown in Table 1, it can be seen that the tires of Examples 1 and 2 are superior in drainage performance at the initial stage of wear and superior in uneven wear resistance as compared with the conventional tire.

この発明により、周方向溝に設けた溝底***部及びブロック陸部の形状の適正化を図って、ブロック陸部に発生する偏摩耗を、タイヤ摩耗初期から摩耗終期にわたって有効に抑制することのできる空気入りタイヤを提供することが可能となった。   According to the present invention, the shape of the groove bottom raised portion and the block land portion provided in the circumferential groove is optimized, and uneven wear occurring in the block land portion is effectively suppressed from the initial stage of tire wear to the end of wear. It became possible to provide a pneumatic tire that can be used.

この発明に従う代表的な空気入りタイヤのトレッド部の一部の展開図である。1 is a development view of a part of a tread portion of a typical pneumatic tire according to the present invention. （ａ）は、図１のＩ−Ｉ線上の断面図であり、（ｂ）は、図１のＩＩ−ＩＩ線上の断面図である。(A) is sectional drawing on the II line of FIG. 1, (b) is sectional drawing on the II-II line of FIG. （ａ）〜（ｄ）は、図１に示すブロック陸部５ｂの１個を抜き出して周方向溝側から見たときの斜視図である。(A)-(d) is a perspective view when extracting one of the block land parts 5b shown in FIG. 1, and seeing from the circumferential direction groove | channel side. この発明に従う他の空気入りタイヤのトレッド部の一部の展開図である。FIG. 6 is a development view of a part of a tread portion of another pneumatic tire according to the present invention.

符号の説明Explanation of symbols

１ トレッド部
２、２ａ、２ｂ、２ｃ、２ｄ 周方向溝
３、３ａ、３ｂ、３ｃ、３ｄ、３ｅ 横溝
４ａ、４ｂ トレッド端
５、５ａ、５ｂ、５ｃ、５ｄ、５ｅ ブロック陸部
６ 溝底***部
７ ブロック陸部の内陸部分
８ａ、８ｂ ブロック陸部の端部
９ａ、９ｂ、９ｃ、９ｄ ブロック陸部の角部
１０ 溝底***部の頂面
１１ 短サイプ
１２ 細溝

1 tread portion 2, 2a, 2b, 2c, 2d circumferential groove 3, 3a, 3b, 3c, 3d, 3e lateral groove 4a, 4b tread end 5, 5a, 5b, 5c, 5d, 5e block land portion 6 groove bottom bulge Part 7 Inland part of block land part 8a, 8b End part of block land part 9a, 9b, 9c, 9d Corner part of block land part 10 Top surface of groove bottom raised part 11 Short sipe 12 Narrow groove

Claims (7)

トレッド部に、タイヤ周方向に沿って延びる複数本の周方向溝と、該周方向溝の少なくとも１本と連通する複数本の横溝とを配設し、該周方向溝、両トレッド端及び該横溝によってトレッド部を多数個のブロック陸部に区画形成してなる空気入りタイヤにおいて、
少なくとも１本の周方向溝に、溝深さが他の部分よりも浅く、かつタイヤ周方向に沿って延びる溝底***部を設け、
該溝底***部を設けた周方向溝に隣接するブロック陸部は、その内陸部分から少なくとも一つの端部又は角部に向かって陸部高さが漸減する曲面状の頂面を有し、
前記溝底***部は、所定の静的負荷条件にて、タイヤ摩耗初期にはそのタイヤ径方向最外端が路面と非接触状態にあり、タイヤ摩耗中期以降にはそのタイヤ径方向最外端が路面と接触状態にある溝深さを有することを特徴とする空気入りタイヤ。 The tread portion is provided with a plurality of circumferential grooves extending along the tire circumferential direction and a plurality of lateral grooves communicating with at least one of the circumferential grooves, the circumferential grooves, both tread ends, In the pneumatic tire formed by dividing the tread part into a large number of block land parts by lateral grooves,
At least one circumferential groove is provided with a groove bottom ridge that has a groove depth shallower than the other part and extends along the tire circumferential direction,
The block land portion adjacent to the circumferential groove provided with the groove bottom raised portion has a curved top surface in which the land height gradually decreases from the inland portion toward at least one end portion or corner portion,
The groove bottom bulge portion has a tire radial direction outermost end in a non-contact state with the road surface at the initial stage of tire wear under a predetermined static load condition, and the tire radial direction outermost end after the middle stage of tire wear. A pneumatic tire characterized by having a groove depth in contact with the road surface. 前記溝底***部での溝深さは、これを設けた周方向溝に開口する横溝の溝深さより深い、請求項１に記載の空気入りタイヤ。   The pneumatic tire according to claim 1, wherein a groove depth at the groove bottom raised portion is deeper than a groove depth of a lateral groove that opens to a circumferential groove provided with the groove bottom raised portion. 前記溝底***部での溝深さは、これを設けた周方向溝に開口する横溝の溝深さより２ｍｍ以上深い、請求項２に記載の空気入りタイヤ。   The pneumatic tire according to claim 2, wherein a groove depth at the groove bottom raised portion is 2 mm or more deeper than a groove depth of a lateral groove opened to a circumferential groove provided with the groove bottom raised portion. 前記溝底***部での溝深さは、５〜７ｍｍの範囲にある、請求項１〜３のいずれか一項に記載の空気入りタイヤ。   The pneumatic tire according to any one of claims 1 to 3, wherein a groove depth at the groove bottom raised portion is in a range of 5 to 7 mm. 前記溝底***部での溝深さは、これを設けた周方向溝に隣接するブロック陸部の端部での陸部高さの３０〜４５％の範囲にある、請求項１〜４のいずれか一項に記載の空気入りタイヤ。   The groove depth at the groove bottom raised portion is in a range of 30 to 45% of a land portion height at an end portion of a block land portion adjacent to a circumferential groove provided with the groove bottom raised portion. The pneumatic tire according to any one of the above. 前記溝底***部を設けた周方向溝に隣接する横溝の溝深さは３〜５ｍｍの範囲にある、請求項１〜５のいずれか一項に記載の空気入りタイヤ。   The pneumatic tire according to any one of claims 1 to 5, wherein a groove depth of a lateral groove adjacent to a circumferential groove provided with the groove bottom raised portion is in a range of 3 to 5 mm. タイヤ幅方向で最も外側に位置する周方向溝に溝底***部を設けてなる、請求項１〜６のいずれか一項に記載の空気入りタイヤ。

The pneumatic tire according to any one of claims 1 to 6, wherein a groove bottom raised portion is provided in a circumferential groove located on the outermost side in the tire width direction.

JP2004315917A 2004-10-29 2004-10-29 Pneumatic tire Expired - Fee Related JP4528091B2 (en)

Priority Applications (1)

Application Number Priority Date Filing Date Title
JP2004315917A JP4528091B2 (en) 2004-10-29 2004-10-29 Pneumatic tire

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
JP2004315917A JP4528091B2 (en) 2004-10-29 2004-10-29 Pneumatic tire

Publications (2)

Publication Number Publication Date
JP2006123786A JP2006123786A (en) 2006-05-18
JP4528091B2 true JP4528091B2 (en) 2010-08-18

Family

ID=36718918

Family Applications (1)

Application Number Title Priority Date Filing Date
JP2004315917A Expired - Fee Related JP4528091B2 (en) 2004-10-29 2004-10-29 Pneumatic tire

Country Status (1)

Country Link
JP (1) JP4528091B2 (en)

Families Citing this family (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JP4695446B2 (en) * 2005-06-17 2011-06-08 住友ゴム工業株式会社 Heavy duty tire
JP5156270B2 (en) * 2007-06-05 2013-03-06 株式会社ブリヂストン Pneumatic tire
JP6617512B2 (en) * 2015-10-14 2019-12-11 住友ゴム工業株式会社 Pneumatic tire
JP6801386B2 (en) * 2016-11-11 2020-12-16 住友ゴム工業株式会社 Heavy load tires

Citations (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JPH09240220A (en) * 1996-03-11 1997-09-16 Bridgestone Corp Pneumatic radial tire for heavy load
JPH1086610A (en) * 1996-09-17 1998-04-07 Bridgestone Corp Pneumatic tire for heavy load
JPH11189013A (en) * 1997-12-25 1999-07-13 Bridgestone Corp Pneumatic tire
JP2004098854A (en) * 2002-09-10 2004-04-02 Bridgestone Corp Pneumatic tire
JP2004216979A (en) * 2003-01-10 2004-08-05 Bridgestone Corp Pneumatic radial tire for heavy load

Patent Citations (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JPH09240220A (en) * 1996-03-11 1997-09-16 Bridgestone Corp Pneumatic radial tire for heavy load
JPH1086610A (en) * 1996-09-17 1998-04-07 Bridgestone Corp Pneumatic tire for heavy load
JPH11189013A (en) * 1997-12-25 1999-07-13 Bridgestone Corp Pneumatic tire
JP2004098854A (en) * 2002-09-10 2004-04-02 Bridgestone Corp Pneumatic tire
JP2004216979A (en) * 2003-01-10 2004-08-05 Bridgestone Corp Pneumatic radial tire for heavy load

Also Published As

Publication number Publication date
JP2006123786A (en) 2006-05-18

Similar Documents

Publication Publication Date Title
JP4656638B2 (en) Pneumatic tire
AU2010207199B2 (en) Tire
JP5314343B2 (en) Pneumatic tire
EP3135504B1 (en) Heavy duty tire
JP2006151083A (en) Tire for heavy load vehicle
JPWO2016121858A1 (en) Pneumatic tire
JP2003063212A (en) Pneumatic tire
EP2452836B1 (en) Heavy duty pneumatic tire
JP2012153156A (en) Pneumatic tire
JPH08324211A (en) Pneumatic tire
CN108454325B (en) Heavy load pneumatic tire
JP4970893B2 (en) Pneumatic tire
JP5276008B2 (en) tire
JP5001623B2 (en) Pneumatic tire
JP3970164B2 (en) Heavy duty pneumatic tire
JP4528091B2 (en) Pneumatic tire
JP2007083822A (en) Pneumatic tire
JP2005088670A (en) Pneumatic tire
KR100592061B1 (en) Pneumatic tire for heavy vehicle
JP2006224926A (en) Pneumatic tire
JP5762216B2 (en) Pneumatic tire
JP4528086B2 (en) Pneumatic tire
JP4191512B2 (en) Heavy duty pneumatic radial tire
JP4690064B2 (en) Pneumatic tire
JP5437851B2 (en) Pneumatic tire

Legal Events

Date Code Title Description
RD04 Notification of resignation of power of attorney

Free format text: JAPANESE INTERMEDIATE CODE: A7424

Effective date: 20060607

A621 Written request for application examination

Free format text: JAPANESE INTERMEDIATE CODE: A621

Effective date: 20070822

RD03 Notification of appointment of power of attorney

Free format text: JAPANESE INTERMEDIATE CODE: A7423

Effective date: 20070822

A977 Report on retrieval

Free format text: JAPANESE INTERMEDIATE CODE: A971007

Effective date: 20100423

TRDD Decision of grant or rejection written
A01 Written decision to grant a patent or to grant a registration (utility model)

Free format text: JAPANESE INTERMEDIATE CODE: A01

Effective date: 20100511

A01 Written decision to grant a patent or to grant a registration (utility model)

Free format text: JAPANESE INTERMEDIATE CODE: A01

A61 First payment of annual fees (during grant procedure)

Free format text: JAPANESE INTERMEDIATE CODE: A61

Effective date: 20100604

FPAY Renewal fee payment (event date is renewal date of database)

Free format text: PAYMENT UNTIL: 20130611

Year of fee payment: 3

R150 Certificate of patent or registration of utility model

Free format text: JAPANESE INTERMEDIATE CODE: R150

Ref document number: 4528091

Country of ref document: JP

Free format text: JAPANESE INTERMEDIATE CODE: R150

R250 Receipt of annual fees

Free format text: JAPANESE INTERMEDIATE CODE: R250

R250 Receipt of annual fees

Free format text: JAPANESE INTERMEDIATE CODE: R250

R250 Receipt of annual fees

Free format text: JAPANESE INTERMEDIATE CODE: R250

R250 Receipt of annual fees

Free format text: JAPANESE INTERMEDIATE CODE: R250

R250 Receipt of annual fees

Free format text: JAPANESE INTERMEDIATE CODE: R250

R250 Receipt of annual fees

Free format text: JAPANESE INTERMEDIATE CODE: R250

R250 Receipt of annual fees

Free format text: JAPANESE INTERMEDIATE CODE: R250

R250 Receipt of annual fees

Free format text: JAPANESE INTERMEDIATE CODE: R250

R250 Receipt of annual fees

Free format text: JAPANESE INTERMEDIATE CODE: R250

LAPS Cancellation because of no payment of annual fees