JP4693020B2

JP4693020B2 - Pneumatic tire

Info

Publication number: JP4693020B2
Application number: JP2001243247A
Authority: JP
Inventors: 正敏丹井
Original assignee: Toyo Tire and Rubber Co Ltd
Current assignee: Toyo Tire Corp
Priority date: 2001-08-10
Filing date: 2001-08-10
Publication date: 2011-06-01
Anticipated expiration: 2021-08-10
Also published as: JP2003054224A

Description

【０００１】
【発明の属する技術分野】
本発明は空気入りタイヤにおいて、特に、タイヤ踏面部のブロック表面に発生する偏摩耗を防止することができる空気入りタイヤに関する。
【０００２】
【従来の技術】
空気入りタイヤ用トレッドパターンとして、駆動性及び制動性が優れたブロックパターンが使用される。ブロックパターンはタイヤ周方向に沿って延びる複数の周方向主溝とタイヤ幅方向に延びる複数の横溝によって分割されたブロックを多数有する。
【０００３】
このようなブロックパターンをタイヤ踏面部に有するタイヤは、走行時に同一ブロック内で、ブロックの先に路面と接触する踏み込み側と、後で路面と接触する蹴り出し側とで剪断外力が異なり、剪断外力がブロックの踏み込み側よりも大きく受けるブロックの蹴り出し側は、踏み込み側よりも摩耗し易く、いわゆるトゥアンドヒール摩耗と呼ばれる偏摩耗が発生し易い。
【０００４】
【発明が解決しようとする課題】
本発明の課題は、ブロックパターンをタイヤ踏面部に有する空気入りタイヤにおいて、トゥアンドヒール摩耗を防止することができる空気入りタイヤを提供することにある。
【０００５】
【課題を解決するための手段】
上記課題を解決するために、鋭意検討した結果、本発明のタイヤは、タイヤのトレッド面にタイヤ周方向に延びる複数の周方向主溝とタイヤ幅方向に延びる複数の横溝が配され、主溝と主溝、主溝とショルダー接地端外側に各々連通する横溝とによって形成される複数のブロックをタイヤ周方向に多数配列するとともに、タイヤ回転方向を一方向に指定した空気入りタイヤにおいて、
前記ブロックの踏み込み側表面ではサイプを配置せず、
前記ブロックの蹴り出し側表面で、異なる方向成分を有する、複数のサイプを前記ブロックに隣接する横溝に連通しないようにタイヤ幅方向に配置したことを特徴とする空気入りタイヤである。
【０００６】
ブロックの蹴り出し側に、前記サイプを複数本配置することによって、前記ブロックの蹴り出し側の剛性が低下する。その結果、走行時に蹴り出し側にかかる剪断外力が緩和され踏み込み側にかかる剪断外力との差が減少して前記ブロックのタイヤ周方向で受ける剪断外力の差が縮小されブロック内での偏摩耗が改善される。
なお、前記サイプを前記ブロックに隣接する横溝に連通しないように配置した理由は、サイプを前記ブロックに隣接する横溝に連通配置した場合、該ブロックのタイヤ幅方向の剪断外力が大きくなり、その結果、偏摩耗が改善されないからである。
【０００７】
なお、異なる方向成分を有するサイプとしては、折れ線状、＋状、×状等が適している。
【０００８】
【発明の実施の形態】
以下、本発明を図によって、詳細に説明する。図１は本発明に係るタイヤの一実施形態を示すタイヤトレッドパターンの概略展開図である。
図１において、Ｒはタイヤ回転方向、１はタイヤトレッド面、２はタイヤトレッド面１をタイヤ回転方向Ｒに連なる縦溝、３はタイヤ幅方向に延びる横溝、４はショルダー接地端、５は縦溝２と横溝３または縦溝２と横溝３及びショルダー接地端４とで囲まれたブロック、Ｆは踏み込み側、Ｋは蹴り出し側、Ｓはサイプ、ＣＬはタイヤ赤道ライン、６はタイヤ赤道ラインＣＬに配した縦溝２１とタイヤ赤道ラインＣＬのタイヤ幅方向外側に配した縦溝２２で挟まれタイヤ周方向に延びるリブである。
【０００９】
図１では、ブロックの蹴り出し側表面で、異なる方向成分を有するジグザグ状サイプＳをブロック５の蹴り出し側Ｋに、隣接する横溝３に対して、略平行に複数個配している。
【００１０】
本発明の異なる方向成分を有するサイプＳの他の例としては図２の（ａ）〜（ｅ）が挙げられる。但し、図２においては、タイヤトレッドパターン全体では無く、タイヤトレッド面の内１つのブロックで、ブロック形状も矩形のものを例示している。
【００１１】
図２（ａ）はＳの字状サイプ、図２（ｂ）、（ｃ）はジグザグ状で、図１とは異なる例のサイプ、図２（ｄ）は＋の字状サイプ、図２（ｅ）はＸの字状サイプの例である。
図２における符号は図１における符号と同じである。
【００１２】
次に、折れ線状サイプを例として、望ましい範囲を図３によって説明する。図３はジグザグ状サイプＳをブロック５の蹴り出し側Ｋに隣接する横溝に対して、略平行に複数個配している。但し、図３においては、タイヤトレッドパターン全体では無く、タイヤトレッド面の内１つのブロックで、ブロック形状も矩形の例である。
図３において、Ｒはタイヤ回転方向、５はブロック、５１はブロック踏み込み側端、５２はブロック蹴り出し側端、５３及び５４はブロック５のタイヤ幅方向端、Ｆは踏み込み側、Ｋは蹴り出し側、Ｓはサイプ、ＡはサイプＳとブロック蹴り出し側端５２との間隔、ＢはサイプＳのタイヤ回転方向（周方向）長さ、ＣはサイプＳ同士の配置間隔、ＤはサイプＳのタイヤ幅方向長さ、Ｅはブロックのタイヤ幅方向端５３、５４に最も近い位置のサイプＳとブロックのタイヤ幅方向端５３、５４との間隔である。
【００１３】
サイプＳとブロック蹴り出し側端５２との間隔Ａは０．５〜３．０ｍｍが望ましい。Ａが０．５ｍｍ未満ではタイヤ幅方向の剪断力が大きくなり、３．０ｍｍを超えると蹴り出し側の剛性の低下が大き過ぎ、何れの場合も偏摩耗の改善効果が不十分である。
サイプＳのタイヤ回転方向（周方向）長さＢは４．０〜６．０ｍｍが望ましい。Ｂが４．０ｍｍ未満ではジグザグ形状が採り難く、６．０ｍｍを超えると蹴り出し側の剛性の低下が大き過ぎて偏摩耗の改善効果が不十分である。
サイプＳ同士の配置間隔Ｃは３．０〜７．０ｍｍが望ましい。Ｃが３．０ｍｍ未満では蹴り出し側の剛性の低下が大き過ぎ、７．０ｍｍを超えると蹴り出し側の剛性の低下が少なく、偏摩耗の改善効果が不十分である。
サイプＳのタイヤ幅方向長さＤは２．０〜４．０ｍｍが望ましい。Ｄが２．０ｍｍ未満ではサイプの方向成分の異なる程度が少なくなり、蹴り出し側の剛性の低下が少なく、４．０ｍｍを超える場合も、サイプの方向成分の異なる程度が少なくなり、蹴り出し側の剛性の低下が少なく偏摩耗の改善効果が不十分である。
ブロックのタイヤ幅方向端５３、５４に最も近い位置のサイプＳとブロックのタイヤ幅方向端５３、５４との間隔Ｅは３〜５ｍｍが望ましい。Ｅが３ｍｍ未満では剛性の低下が大きすぎ、５ｍｍを超えるとが剛性の低下が少なすぎる。
なお、本発明において、通常、サイプ幅は０．３〜０．６ｍｍ、サイプ深さは該ブロックに隣接する横溝深さの１／２とする。
【００１４】
【実施例】
次に、実施例として、タイヤサイズ２０５／５５Ｒ１６で、トレッドパターンとして図１に示す概略展開図のタイヤを、比較のために比較例１、２として、タイヤサイズ２０５／５５Ｒ１６で、トレッドパターンとして各々、図４、図５に示す概略展開図のタイヤを作成してリム６−１／２Ｊ×１６を使用して、空気内圧２００ｋｐａで、車両に装着してタイヤ１本当たり荷重３２０kｇで１２，０００Ｋｍ実地走行させ、走行後のブロックの踏み込み側と蹴り出し側の摩耗量の差を測定して、この値の逆数を実施例タイヤを１００として指数評価した。数値が大である程、良好である。
【００１５】
なお、実施例、比較例１、比較例２ともに、サイプとブロック蹴り出し側端との間隔（図３のＡに相当）はタイヤ幅方向両端部（ショルダー部）ブロックでは１．５ｍｍ、タイヤ幅方向内側（タイヤ赤道線側）のブロックでは１．５ｍｍ、サイプのブロック踏み込み側端（図３の５１に相当）に平行な配置範囲はタイヤ幅方向両端部（ショルダー部）ブロックでは２０ｍｍ、タイヤ幅方向内側（タイヤ赤道線側）のブロックでは２０ｍｍ、サイプのタイヤ周方向配置範囲（図３のＢに相当）は実施例、比較例１、比較例２ともに、タイヤ幅方向両端部（ショルダー部）ブロックで５ｍｍ、タイヤ幅方向内側（タイヤ赤道線側）ブロックで５ｍｍ、サイプ深さは実施例、比較例１、比較例２ともにタイヤ幅方向両端部（ショルダー部）ブロック、タイヤ幅方向内側（タイヤ赤道線側）ブロック何れにおいても３ｍｍ、サイプ幅は実施例、比較例１、比較例２ともにタイヤ幅方向両端部（ショルダー部）ブロック、タイヤ幅方向内側（タイヤ赤道線側）ブロック何れにおいても０．３ｍｍ、縦溝深さは実施例、比較例１、比較例２ともに何れの箇所においても８．２ｍｍ、横溝深さは実施例、比較例１、比較例２ともに何れの箇所においても６．７ｍｍとした。
【００１６】
評価結果を表１に示す。
【表１】

【００１７】
表１から本発明に係る実施例のタイヤは、比較例タイヤに比べて、偏摩耗性が改善されていることが認められる。
【００１８】
【発明の効果】
以上、詳細に説明したように、本発明の空気入りタイヤはタイヤのトレッド面にタイヤ周方向に延びる複数の周方向主溝とタイヤ幅方向に延びる複数の横溝が配され、主溝と主溝、主溝とショルダー接地端外側に各々連通する横溝とによって形成される複数のブロックをタイヤ周方向に多数配列するとともに、タイヤ回転方向を一方向に指定した空気入りタイヤにおいて、
前記ブロックの踏み込み側表面ではサイプを配置せず、
前記ブロックの蹴り出し側表面で、異なる方向成分を有するサイプを前記ブロックに隣接する横溝に連通しないように複数本配置したので、
走行時に蹴り出し側にかかる剪断外力が緩和され踏み込み側にかかる剪断外力との差が減少して前記ブロックのタイヤ周方向で受ける剪断外力の差が縮小されブロック内での偏摩耗が改善される。
【００１９】
【図面の簡単な説明】
【図１】本発明に係るタイヤの一実施形態を示すタイヤトレッドパターンの概略展開図である。
【図２】（ａ）〜（ｅ）は本発明に係るタイヤの他の実施形態を示すタイヤトレッドパターンの部分概略図である。
【図３】本発明に係るタイヤの一実施形態を示すタイヤトレッドパターンの部分概略図である。
【図４】従来技術のタイヤのタイヤトレッドパターンの概略展開図である。
【図５】従来技術のタイヤのタイヤトレッドパターンの概略展開図である。
【符号の説明】
１タイヤトレッド面
２縦溝
３横溝
４ショルダー接地端
５ブロック
Ｆ踏み込み側
Ｋ蹴り出し側
Ｓサイプ
Ｒタイヤ回転方向[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a pneumatic tire, and more particularly to a pneumatic tire capable of preventing uneven wear occurring on a block surface of a tire tread.
[0002]
[Prior art]
As a tread pattern for a pneumatic tire, a block pattern having excellent driving performance and braking performance is used. The block pattern has a large number of blocks divided by a plurality of circumferential main grooves extending along the tire circumferential direction and a plurality of lateral grooves extending in the tire width direction.
[0003]
A tire having such a block pattern on the tire tread surface has a different shearing external force in the same block during traveling, on the stepping side that comes into contact with the road surface ahead of the block and on the kicking side that comes into contact with the road surface later. The kicking side of the block that receives an external force larger than the stepping side of the block is more easily worn than the stepping side, and uneven wear called so-called toe and heel wear is likely to occur.
[0004]
[Problems to be solved by the invention]
The subject of this invention is providing the pneumatic tire which can prevent toe-and-heel abrasion in the pneumatic tire which has a block pattern in a tire tread part.
[0005]
[Means for Solving the Problems]
As a result of intensive studies to solve the above-described problems, the tire of the present invention is provided with a plurality of circumferential main grooves extending in the tire circumferential direction and a plurality of lateral grooves extending in the tire width direction on the tread surface of the tire. In a pneumatic tire in which a plurality of blocks formed by a main groove, a main groove, and a lateral groove communicating with each other on the outside of the shoulder grounding end are arranged in the tire circumferential direction, and the tire rotation direction is designated in one direction,
No sipes are placed on the stepping side surface of the block,
A pneumatic tire characterized in that a plurality of sipes having different directional components are arranged in a tire width direction so as not to communicate with a lateral groove adjacent to the block on the kicking side surface of the block.
[0006]
By arranging a plurality of the sipes on the kicking side of the block, the rigidity on the kicking side of the block is lowered. As a result, the shear external force applied to the kicking side during running is reduced, the difference from the shear external force applied to the stepping side is reduced, the difference in shear external force received in the tire circumferential direction of the block is reduced, and uneven wear in the block is reduced. Improved.
The reason why the sipe is arranged not to communicate with the lateral groove adjacent to the block is that when the sipe is arranged to communicate with the lateral groove adjacent to the block, the shear external force in the tire width direction of the block increases, and as a result This is because uneven wear is not improved.
[0007]
In addition, as a sipe having different direction components, a polygonal line shape, a + shape, an X shape, and the like are suitable.
[0008]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, the present invention will be described in detail with reference to the drawings. FIG. 1 is a schematic development view of a tire tread pattern showing an embodiment of a tire according to the present invention.
In FIG. 1, R is a tire rotation direction, 1 is a tire tread surface, 2 is a vertical groove that connects the tire tread surface 1 to the tire rotation direction R, 3 is a horizontal groove that extends in the tire width direction, 4 is a shoulder grounding end, and 5 is a vertical contact. Block surrounded by groove 2 and transverse groove 3 or longitudinal groove 2 and transverse groove 3 and shoulder grounding end 4, F is a stepping side, K is a kicking side, S is a sipe, CL is a tire equator line, and 6 is a tire equator line A rib extending between the longitudinal groove 21 disposed in the CL and the longitudinal groove 22 disposed outside the tire equator line CL in the tire width direction extends in the tire circumferential direction.
[0009]
In FIG. 1, a plurality of zigzag sipe S having different directional components on the kicking side surface of the block are arranged on the kicking side K of the block 5 substantially in parallel to the adjacent lateral grooves 3.
[0010]
Other examples of the sipe S having different directional components according to the present invention include (a) to ( e ) in FIG. However, in FIG. 2, not the whole tire tread pattern but one block of the tire tread surface and the block shape is illustrated as a rectangle.
[0011]
2 (a) is an S-shaped sipe, FIGS. 2 (b) and 2 (c ) are zigzag shapes, an example of a sipe different from FIG. 1, FIG. 2 (d) is a + -shaped sipe, FIG. e ) is an example of an X-shaped sipe.
The reference numerals in FIG. 2 are the same as those in FIG.
[0012]
Next, a desirable range will be described with reference to FIG. 3 by taking a polygonal sipe as an example. In FIG. 3, a plurality of zigzag sipe S are arranged substantially parallel to the lateral groove adjacent to the kicking side K of the block 5. However, in FIG. 3, it is not the whole tire tread pattern but one block of the tire tread surface, and the block shape is also an example of a rectangle.
In FIG. 3, R is the tire rotation direction, 5 is the block, 51 is the block stepping side end, 52 is the block kicking side end, 53 and 54 are the tire width direction ends of the block 5, F is the stepping side, and K is kicking out. Side, S is sipe, A is the distance between the sipe S and the block kick-out side end 52, B is the length of the sipe S in the tire rotation direction (circumferential direction), C is the spacing between the sipe S, D is the sipe S The tire width direction length E is the distance between the sipe S closest to the tire

width direction ends

53 and 54 of the block and the tire width direction ends 53 and 54 of the block.
[0013]
The distance A between the sipe S and the block kick-out side end 52 is preferably 0.5 to 3.0 mm. If A is less than 0.5 mm, the shearing force in the tire width direction increases, and if it exceeds 3.0 mm, the rigidity on the kick-out side is excessively reduced, and in any case, the effect of improving uneven wear is insufficient.
The tire rotation direction (circumferential direction) length B of the sipe S is preferably 4.0 to 6.0 mm. If B is less than 4.0 mm, it is difficult to adopt a zigzag shape, and if it exceeds 6.0 mm, the decrease in rigidity on the kicking side is too great and the effect of improving uneven wear is insufficient.
The arrangement interval C between the sipes S is preferably 3.0 to 7.0 mm. If C is less than 3.0 mm, the decrease in rigidity on the kick-out side is too large, and if it exceeds 7.0 mm, the decrease in rigidity on the kick-out side is small, and the effect of improving uneven wear is insufficient.
The length D in the tire width direction of the sipe S is desirably 2.0 to 4.0 mm. When D is less than 2.0 mm, the degree of difference in the sipe direction component is small, and the rigidity of the kicking side is less decreased. When the value exceeds 4.0 mm, the degree of difference in the sipe direction component is small, and the kicking side The effect of improving uneven wear is insufficient.
The distance E between the sipe S closest to the tire

width direction ends

53 and 54 of the block and the tire width direction ends 53 and 54 of the block is preferably 3 to 5 mm. When E is less than 3 mm, the decrease in rigidity is too large, and when it exceeds 5 mm, the decrease in rigidity is too small.
In the present invention, the sipe width is usually 0.3 to 0.6 mm, and the sipe depth is ½ of the lateral groove depth adjacent to the block.
[0014]
【Example】
Next, as an example, the tire shown in FIG. 1 as a tread pattern with a tire size of 205 / 55R16 is shown as a tread pattern, and for comparison, as Comparative Examples 1 and 2, as a tread pattern with a tire size of 205 / 55R16. 4 and FIG. 5 are used to create tires having schematic development views, and are mounted on a vehicle using a rim 6-1 / 2J × 16 at an internal air pressure of 200 kpa and loaded at 12,000 km per tire with a load of 320 kg. The actual running was performed, and the difference in wear amount between the stepping-in side and the kicking-out side of the block after running was measured. The larger the value, the better.
[0015]
Note that in both the example, comparative example 1 and comparative example 2, the distance between the sipe and the block kicking side end (corresponding to A in FIG. 3) is 1.5 mm at the tire width direction both ends (shoulder portion) block, and the tire width. 1.5 mm for the block on the inner side (tire equator line side), 20 mm for the tire width direction both ends (shoulder portion) block, and the tire width in parallel with the sipe block stepping side end (corresponding to 51 in FIG. 3) 20 mm for the block on the inner side in the direction (tire equator line side), and the arrangement range of the sipe in the tire circumferential direction (corresponding to B in FIG. 3) is both ends in the tire width direction (shoulder portion) in both Example, Comparative Example 1 and Comparative Example 2. Block 5mm, tire width direction inner side (tire equator line side) block 5mm, sipe depth in both tire width direction both ends (shoulder portion) block for both Example, Comparative Example 1 and Comparative Example 2 Tire width direction inner side (tire equatorial line side) block 3 mm in all, sipe width in both the example, comparative example 1 and comparative example 2 tire width direction both ends (shoulder part) block, tire width direction inner side (tire equatorial line side) ) 0.3 mm in any block, the depth of the longitudinal groove is 8.2 mm in any part of both Example, Comparative Example 1 and Comparative Example 2, and the depth of the lateral groove is any in both Example, Comparative Example 1 and Comparative Example 2 It was set to 6.7 mm also in this part.
[0016]
The evaluation results are shown in Table 1.
[Table 1]

[0017]
It can be seen from Table 1 that the tires of the examples according to the present invention have improved uneven wear compared to the comparative example tires.
[0018]
【The invention's effect】
As described above in detail, in the pneumatic tire of the present invention, a plurality of circumferential main grooves extending in the tire circumferential direction and a plurality of lateral grooves extending in the tire width direction are arranged on the tread surface of the tire. In the pneumatic tire in which a plurality of blocks formed by a main groove and a lateral groove communicating with each other on the outside of the shoulder grounding end are arranged in the tire circumferential direction, and the tire rotation direction is designated in one direction,
No sipes are placed on the stepping side surface of the block,
Since a plurality of sipes having different directional components are arranged on the kicking side surface of the block so as not to communicate with the lateral groove adjacent to the block,
The shear external force applied to the kick-out side during running is reduced, the difference from the shear external force applied to the stepping side is reduced, the difference in shear external force received in the tire circumferential direction of the block is reduced, and uneven wear in the block is improved .
[0019]
[Brief description of the drawings]
FIG. 1 is a schematic development view of a tire tread pattern showing an embodiment of a tire according to the present invention.
Figure 2 (a) ~ (e) is a partial schematic view of a tire tread pattern showing another embodiment of a tire according to the present invention.
FIG. 3 is a partial schematic view of a tire tread pattern showing an embodiment of a tire according to the present invention.
FIG. 4 is a schematic development view of a tire tread pattern of a conventional tire.
FIG. 5 is a schematic development view of a tire tread pattern of a conventional tire.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 1 Tire tread surface 2 Vertical groove 3 Horizontal groove 4 Shoulder grounding edge 5 Block F Depression side K Kick-out side S Sipe R Tire rotation direction

Claims

A plurality of circumferential main grooves extending in the tire circumferential direction and a plurality of lateral grooves extending in the tire width direction are arranged on the tread surface of the tire, and formed by the main groove and the main groove, and the lateral grooves communicating with the main groove and the outer side of the shoulder ground end respectively. In a pneumatic tire in which a plurality of blocks are arranged in the tire circumferential direction and the tire rotation direction is designated as one direction,
No sipes are placed on the stepping side surface of the block,
A pneumatic tire characterized in that a plurality of S-shaped sipes are arranged in a tire width direction so as not to communicate with a lateral groove adjacent to the block on the kicking side surface of the block.

A plurality of circumferential main grooves extending in the tire circumferential direction and a plurality of lateral grooves extending in the tire width direction are arranged on the tread surface of the tire, and formed by the main groove and the main groove, and the lateral grooves communicating with the main groove and the outer side of the shoulder ground end respectively. In a pneumatic tire in which a plurality of blocks are arranged in the tire circumferential direction and the tire rotation direction is designated as one direction,
No sipes are placed on the stepping side surface of the block,
A pneumatic tire characterized in that a plurality of zigzag sipes are arranged in the tire width direction so as not to communicate with a lateral groove adjacent to the block on the kicking side surface of the block .

A plurality of circumferential main grooves extending in the tire circumferential direction and a plurality of lateral grooves extending in the tire width direction are arranged on the tread surface of the tire, and formed by the main groove and the main groove, and the lateral grooves communicating with the main groove and the outer side of the shoulder ground end respectively. In a pneumatic tire in which a plurality of blocks are arranged in the tire circumferential direction and the tire rotation direction is designated as one direction,
No sipes are placed on the stepping side surface of the block,
A pneumatic tire characterized in that a plurality of + -shaped sipes are arranged in a tire width direction so as not to communicate with a lateral groove adjacent to the block on the kick-out side surface of the block .

A plurality of circumferential main grooves extending in the tire circumferential direction and a plurality of lateral grooves extending in the tire width direction are arranged on the tread surface of the tire, and formed by the main groove and the main groove, and the lateral grooves communicating with the main groove and the outer side of the shoulder ground end respectively. In a pneumatic tire in which a plurality of blocks are arranged in the tire circumferential direction and the tire rotation direction is designated as one direction,
No sipes are placed on the stepping side surface of the block,
A pneumatic tire characterized in that a plurality of X-shaped sipes are arranged in the tire width direction so as not to communicate with a lateral groove adjacent to the block on the kicking side surface of the block .