JP5234269B2 - Pneumatic tire - Google Patents

Pneumatic tire Download PDF

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JP5234269B2
JP5234269B2 JP2008253869A JP2008253869A JP5234269B2 JP 5234269 B2 JP5234269 B2 JP 5234269B2 JP 2008253869 A JP2008253869 A JP 2008253869A JP 2008253869 A JP2008253869 A JP 2008253869A JP 5234269 B2 JP5234269 B2 JP 5234269B2
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tire
groove
chamfered
length
wall surface
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JP2010083303A (en
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崇史 干場
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Yokohama Rubber Co Ltd
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Yokohama Rubber Co Ltd
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    • 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
    • B60C11/1307—Tread patterns characterised by the groove cross-section, e.g. for buttressing or preventing stone-trapping with special features of the groove walls
    • B60C11/1323—Tread patterns characterised by the groove cross-section, e.g. for buttressing or preventing stone-trapping with special features of the groove walls asymmetric

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

Description

本発明は、例えば乗用車、トラック、バス等に用いられる空気入りタイヤに関するものである。   The present invention relates to a pneumatic tire used in, for example, passenger cars, trucks, buses and the like.

従来、この種の空気入りタイヤとしては、タイヤ周方向に延びる主溝とタイヤ幅方向に延びるラグ溝によってブロックを区画形成したものが一般的であるが、ブロックの蹴り出し側端部が路面と接触する際の騒音を低減するために、ブロックの蹴り出し側端部にブロックの幅方向中央側が幅方向両側よりもタイヤ周方向に突出する突出部を設けることにより、ブロックの蹴り出し側端部がタイヤ幅方向に亘って徐々に路面に接するようにしたものが知られている（例えば、特許文献１参照。）。
特開平９−２０７５２０号公報 Conventionally, as this type of pneumatic tire, a block is generally formed by a main groove extending in the tire circumferential direction and a lug groove extending in the tire width direction, but the kicking side end of the block is a road surface. In order to reduce noise at the time of contact, the block's kick-out side end is provided at the block's kick-out side end by providing a protrusion in which the center side in the width direction of the block protrudes in the tire circumferential direction from both sides in the width direction. Is known that gradually contacts the road surface in the tire width direction (see, for example, Patent Document 1).
JP-A-9-207520

ところで、前記ブロックには、いわゆるヒールアンドトゥ摩耗（偏摩耗の一種）が発生しやすいという問題がある。ヒールアンドトゥ摩耗は、タイヤの制動力によってブロックがタイヤ回転方向に繰り返し剪断力を受けることにより発生し、ブロックの蹴り出し側が高い接地圧となって摩耗が多くなる一方、ブロックの踏み込み側は接地圧が低くなる分、路面との滑りによる摩耗でエッジ部が薄く延び、この延びた部分が路面を叩く打音によって騒音が増大する。特に、前述のような突出部をブロックの蹴り出し側に設けたものでは、その分だけブロックの蹴り出し側の接地圧が高くなり、ヒールアンドトゥ摩耗を増大させるという問題点があった。   However, the block has a problem that so-called heel and toe wear (a kind of uneven wear) is likely to occur. Heel-and-toe wear occurs when the block receives repeated shearing force in the tire rotation direction due to the braking force of the tire, and wear increases due to high ground pressure on the kicking side of the block, while ground pressure occurs on the stepping side of the block. The edge portion extends thinly due to wear due to sliding with the road surface, and noise increases due to the hitting sound of the extended portion hitting the road surface. In particular, in the case where the protruding portion as described above is provided on the kicking side of the block, there is a problem that the contact pressure on the kicking side of the block is increased by that amount, and heel and toe wear is increased.

本発明は前記問題点に鑑みてなされたものであり、その目的とするところは、ブロックの蹴り出し側端部にタイヤ周方向に突出する突出部を設けたものであっても、ヒールアンドトゥ摩耗を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。   The present invention has been made in view of the above problems, and the object of the present invention is to provide heel and toe wear even when a protruding portion protruding in the tire circumferential direction is provided at the kicking side end portion of the block. It is providing the pneumatic tire which can be suppressed.

本発明は前記目的を達成するために、タイヤ周方向に延びる主溝と、タイヤ幅方向に延びるラグ溝と、主溝及びラグ溝によって区画形成されるブロックとを備え、ブロックの蹴り出し側端部にブロックの幅方向中央側が幅方向両側よりもタイヤ周方向に突出する突出部を設けた空気入りタイヤにおいて、前記ブロックの接地面と突出部側のラグ溝の溝壁面との間に面取り部を設け、面取り部を、そのタイヤ周方向一端から他端までの面取り長さが突出部の幅方向両側よりも幅方向中央側が長くなるように形成するとともに、面取り部を、面取り長さの最も長くなる部分の面取り長さが、その部分におけるブロックの蹴り出し側端部から踏み込み側端部までの長さの２％以上２０％以下になるように形成し、突出部の蹴り出し側端部をその幅方向中央側から両端側に亘って曲線状をなすように形成している。 In order to achieve the above object, the present invention comprises a main groove extending in the tire circumferential direction, a lug groove extending in the tire width direction, and a block defined by the main groove and the lug groove, and the kicking side end of the block In a pneumatic tire in which a central portion in the width direction of the block is provided with a protruding portion that protrudes in the tire circumferential direction from both sides in the width direction, a chamfered portion between the grounding surface of the block and the groove wall surface of the lug groove on the protruding portion side The chamfered portion is formed such that the chamfered length from one end to the other end in the tire circumferential direction is longer on the center side in the width direction than on both sides in the widthwise direction of the protruding portion , and the chamfered portion has the largest chamfered length. The chamfered length of the longer part is 2% or more and 20% or less of the length from the kicking side edge of the block to the stepping side edge of the part, and the kicking side edge of the protruding part The width It is formed so as to form a curved shape over the central side at both ends.

これにより、ブロックの蹴り出し側端部に設けられる突出部に面取り部が設けられていることから、突出部の接地圧が少なくなり、ヒールアンドトゥ摩耗が抑制される。この場合、面取り部が、タイヤ周方向一端から他端までの面取り長さが突出部の幅方向中央側が幅方向両側よりも長くなるように形成されていることから、突出部において最も摩耗しやすい幅方向中央側（先端側）から幅方向両側に亘ってほぼ均一な接地圧になる。また、面取り部が、面取り長さの最も長くなる部分の面取り長さが、その部分におけるブロックの蹴り出し側端部から踏み込み側端部までの長さの２％以上２０％以下になるように形成されていることから、面取りによって必要以上にブロックの接地面積を減少させることがない。更に、突出部の蹴り出し側端部がその幅方向中央側から両端側に亘って曲線状をなすように形成されていることから、突出部の幅方向中央側（先端側）の摩耗量が部分的に多くなることがない。 Thereby, since the chamfered portion is provided at the protruding portion provided at the kick-out side end portion of the block, the ground pressure of the protruding portion is reduced, and heel and toe wear is suppressed. In this case, the chamfered portion is formed so that the chamfered length from one end to the other end in the tire circumferential direction is longer at the center in the width direction than the both sides in the width direction. The contact pressure is substantially uniform from the center in the width direction (tip side) to both sides in the width direction. Further, the chamfered portion of the chamfered portion having the longest chamfered length is 2% or more and 20% or less of the length of the block from the kicking side end portion to the stepping side end portion. Since it is formed, the ground contact area of the block is not reduced more than necessary by chamfering. Furthermore, since the protruding side end of the protruding portion is formed in a curved shape from the center in the width direction to both ends, the amount of wear on the center in the width direction (tip side) of the protruding portion is reduced. There is no partial increase.

本発明によれば、突出部の接地圧を少なくすることができるので、ヒールアンドトゥ摩耗を抑制することができ、走行時の騒音低減に極めて効果的である。この場合、突出部において最も摩耗しやすい幅方向中央側（先端側）から幅方向両側に亘ってほぼ均一な接地圧にすることができるので、操縦安定性を低下させることなく耐偏摩耗性の向上を図ることができる。また、面取りによって必要以上にブロックの接地面積を減少させることないので、ヒールアンドトゥ摩耗の抑制効果を十分に得ることができる。更に、突出部の幅方向中央側（先端側）の摩耗量が部分的に多くなることがないので、突出部の幅方向の偏摩耗を抑制することができる。 According to the present invention, since the contact pressure of the projecting portion can be reduced, heel and toe wear can be suppressed, which is extremely effective in reducing noise during traveling. In this case, since the contact pressure can be made substantially uniform from the center in the width direction (tip side) where the protrusions are most likely to be worn to both sides in the width direction, uneven wear resistance can be achieved without deteriorating steering stability. Improvements can be made. Moreover, since the ground contact area of the block is not reduced more than necessary by chamfering, the effect of suppressing heel and toe wear can be sufficiently obtained. Furthermore, since the amount of wear on the center side (tip side) in the width direction of the protruding portion does not partially increase, uneven wear in the width direction of the protruding portion can be suppressed.

図１乃至図４は本発明の第１の実施形態を示すもので、図１は空気入りタイヤの部分正面断面図、図２はその部分平面図、図３はブロックの平面図、図４はその側面断面図である。   1 to 4 show a first embodiment of the present invention. FIG. 1 is a partial front sectional view of a pneumatic tire, FIG. 2 is a partial plan view thereof, FIG. 3 is a plan view of a block, and FIG. FIG.

同図に示す空気入りタイヤは、タイヤ外周面側に形成されるトレッド部１と、タイヤ幅方向両側に形成されるサイドウォール部２と、トレッド部１とサイドウォール部２との間に形成されるショルダー部３と、サイドウォール部２のタイヤ径方向内側に形成されるビード部４とを備え、ビード部４にはビードコア４ａが埋設されている。   The pneumatic tire shown in the figure is formed between a tread portion 1 formed on the tire outer peripheral surface side, sidewall portions 2 formed on both sides in the tire width direction, and the tread portion 1 and the sidewall portions 2. A shoulder portion 3 and a bead portion 4 formed on the inner side in the tire radial direction of the sidewall portion 2, and a bead core 4 a is embedded in the bead portion 4.

トレッド部１には、タイヤ周方向に延びる複数の主溝５と、タイヤ幅方向に延びる複数のラグ溝６と、主溝５とラグ溝６によって区画形成される複数のブロック７が設けられている。各ブロック７の蹴り出し側端部にはブロック７の幅方向中央側が幅方向両側よりもタイヤ周方向に突出する突出部７ａが設けられ、突出部７ａの蹴り出し側端部はその幅方向中央側から両端側に亘って曲線状をなすように形成されている。また、ブロック７の接地面と突出部７ａ側のラグ溝６の溝壁面との間には面取り部７ｂが設けられ、面取り部７ｂはそのタイヤ周方向一端Ｐ1 から他端Ｐ2 までの面取り長さＬ1 が突出部７ａの幅方向両側よりも幅方向中央側が徐々に長くなるように形成されている。この場合、面取り部７ｂは、面取り長さＬ1 の最も長くなる部分の面取り長さＬ1 が、その部分におけるブロック７の蹴り出し側端部から踏み込み側端部までの長さ（面取り長さＬ1 に、面取り部７ｂのタイヤ周方向他端Ｐ2 からブロック７の踏み込み側端部Ｐ3 までの長さＬ2 を加えた長さ）の２％以上２０％以下になるように形成されている。また、面取り部７ｂは、面取り長さＬ1 の最も長くなる部分の蹴り出し側端部におけるタイヤ径方向の面取り深さＨが１ｍｍ以上２ｍｍ以下になるように形成されている。   The tread portion 1 is provided with a plurality of main grooves 5 extending in the tire circumferential direction, a plurality of lug grooves 6 extending in the tire width direction, and a plurality of blocks 7 defined by the main grooves 5 and the lug grooves 6. Yes. Each block 7 is provided with a protruding portion 7a at the center side in the width direction that protrudes in the tire circumferential direction from both sides in the width direction, and the kicking side end portion of the protruding portion 7a is the center in the width direction. It is formed so as to form a curved shape from the side to both ends. Further, a chamfered portion 7b is provided between the grounding surface of the block 7 and the groove wall surface of the lug groove 6 on the protruding portion 7a side, and the chamfered portion 7b has a chamfered length from one end P1 to the other end P2 in the tire circumferential direction. L1 is formed so that the center side in the width direction is gradually longer than both sides in the width direction of the protruding portion 7a. In this case, in the chamfered portion 7b, the chamfered length L1 of the longest portion of the chamfered length L1 is the length from the kicking side end of the block 7 to the stepped side end (the chamfered length L1). The length of the chamfered portion 7b from the other end P2 in the tire circumferential direction to the stepped-side end portion P3 of the block 7 is 2% to 20%. Further, the chamfered portion 7b is formed such that the chamfering depth H in the tire radial direction at the end portion on the kick-out side of the portion having the longest chamfering length L1 is 1 mm or more and 2 mm or less.

以上のように構成された空気入りタイヤにおいては、ブロック７の突出部７ａに面取り部７ｂが設けられているため、突出部７ａの接地圧が少なくなり、ヒールアンドトゥ摩耗が抑制される。この場合、面取り部７ｂのタイヤ周方向一端Ｐ1 から他端Ｐ2 までの面取り長さＬ1 が突出部７ａの幅方向中央側が幅方向両側よりも長くなっていることから、突出部７ａにおいて最も摩耗しやすい幅方向中央側（先端側）から幅方向両側に亘ってほぼ均一な接地圧になる。   In the pneumatic tire configured as described above, since the chamfered portion 7b is provided on the protruding portion 7a of the block 7, the ground pressure of the protruding portion 7a is reduced, and heel and toe wear is suppressed. In this case, the chamfering length L1 from the tire circumferential direction one end P1 to the other end P2 of the chamfered portion 7b is longer at the center in the width direction of the protruding portion 7a than at both sides in the widthwise direction. The contact pressure is almost uniform from the center in the width direction (tip side) to both sides in the width direction.

このように、本実施形態によれば、ブロック７の蹴り出し側端部に設けられる突出部７ａに面取り部７ｂを設けたので、突出部７ａの接地圧を少なくしてヒールアンドトゥ摩耗を抑制することができ、走行時の騒音低減に極めて効果的である。この場合、面取り部７ｂを、タイヤ周方向一端Ｐ1 から他端Ｐ2 までの面取り長さＬ1 が突出部７ａの幅方向中央側が幅方向両側よりも長くなるように形成したので、突出部７ａにおいて最も摩耗しやすい幅方向中央側（先端側）から幅方向両側に亘ってほぼ均一な接地圧にすることができ、操縦安定性を低下させることなく耐偏摩耗性の向上を図ることができる。   Thus, according to the present embodiment, since the chamfered portion 7b is provided on the protruding portion 7a provided at the kick-out side end portion of the block 7, the ground pressure of the protruding portion 7a is reduced and heel and toe wear is suppressed. It is extremely effective in reducing noise during driving. In this case, the chamfered portion 7b is formed so that the chamfering length L1 from the tire circumferential direction one end P1 to the other end P2 is longer at the center in the width direction of the protruding portion 7a than at both sides in the width direction. A substantially uniform contact pressure can be obtained from the widthwise center side (tip side), which tends to wear, to both sides in the width direction, and uneven wear resistance can be improved without deteriorating steering stability.

また、面取り部７ｂを、面取り長さＬ1 の最も長くなる部分の面取り長さＬ1 が、その部分におけるブロックの蹴り出し側端部から踏み込み側端部までの長さの２％以上２０％以下になるように形成したので、面取りによって必要以上にブロック７の接地面積を減少させることなくヒールアンドトゥ摩耗の抑制効果を十分に得ることができる。   Further, in the chamfered portion 7b, the chamfering length L1 of the longest portion of the chamfering length L1 is 2% or more and 20% or less of the length from the block kicking side end to the stepping side end of the block. Therefore, the effect of suppressing the heel and toe wear can be sufficiently obtained without reducing the ground contact area of the block 7 more than necessary by chamfering.

更に、突出部７ａの蹴り出し側端部をその幅方向中央側から両端側に亘って曲線状をなすように形成したので、突出部７ａの幅方向中央側（先端側）の摩耗量が部分的に多くなることがなく、突出部７ａの幅方向の偏摩耗を抑制することができる。   Further, since the kick-out side end portion of the protruding portion 7a is formed to be curved from the width direction center side to both end sides, the amount of wear on the width direction center side (tip side) of the protrusion portion 7a is partially Therefore, uneven wear in the width direction of the protrusion 7a can be suppressed.

また、面取り部７ｂを、面取り長さＬ1 の最も長くなる部分の蹴り出し側端部におけるタイヤ径方向の面取り深さＨが１ｍｍ以上２ｍｍ以下になるように形成したので、面取りによって必要以上にブロック７の接地面積を減少させることなくヒールアンドトゥ摩耗の抑制効果を十分に得ることができる。   Further, since the chamfered portion 7b is formed so that the chamfering depth H in the tire radial direction at the kick-out side end portion of the longest portion of the chamfer length L1 is 1 mm or more and 2 mm or less, the chamfering blocks more than necessary. The effect of suppressing the heel and toe wear can be sufficiently obtained without reducing the contact area of 7.

図５は本発明の第２の実施形態を示すブロックの側面断面図であり、突出部７ａの面取り部７ｂを、タイヤ周方向一端Ｐ1 から他端Ｐ2 に亘ってタイヤ径方向外側に凸状をなす曲線状に形成したものである。これにより、ブロック７の蹴り出し側端部がタイヤ周方向に亘って徐々に路面に接することから、面取り部７ｂの摩耗量をより低減することができる。   FIG. 5 is a side sectional view of a block showing a second embodiment of the present invention, in which the chamfered portion 7b of the projecting portion 7a is convex outward in the tire radial direction from one end P1 to the other end P2. It is formed in a curved shape. Thereby, since the kicking side end of the block 7 gradually contacts the road surface in the tire circumferential direction, the wear amount of the chamfered portion 7b can be further reduced.

図６は本発明の第３の実施形態を示すブロックの側面断面図であり、ラグ溝６の底部に、一方の溝壁面６ａから突出部７ａ側の他方の溝壁面６ｂに向かってタイヤ径方向の溝深さＤが徐々に浅くなる底上げ部６ｃを設けたものである。これにより、ブロック７における突出部７ａ側の剛性を高めることができるので、面取り部７ｂの摩耗量をより低減することができる。   FIG. 6 is a side cross-sectional view of a block showing a third embodiment of the present invention, in the tire radial direction from one groove wall surface 6a to the other groove wall surface 6b on the protruding portion 7a side at the bottom of the lug groove 6. The bottom raised portion 6c in which the groove depth D gradually decreases is provided. Thereby, since the rigidity by the side of the protrusion part 7a in the block 7 can be improved, the abrasion loss of the chamfering part 7b can be reduced more.

この場合、底上げ部６ｃを、突出部７ａの面取り長さＬ1 が長くなると、突出部７ａ側の溝壁面６ｂの溝深さＤが浅くなるように形成すれば、突出部７ａ側の剛性を突出部７ａの幅方向に亘って面取り長さＬ1 に応じた適正な剛性にすることができ、操縦安定性の向上に効果的である。   In this case, if the bottom raised portion 6c is formed so that the groove depth D of the groove wall surface 6b on the protruding portion 7a side becomes shallower as the chamfer length L1 of the protruding portion 7a becomes longer, the rigidity on the protruding portion 7a side protrudes. Appropriate rigidity corresponding to the chamfering length L1 can be obtained over the width direction of the portion 7a, which is effective in improving the steering stability.

図７は本発明の第４の実施形態を示すブロックの側面断面図であり、ラグ溝６における突出部７ａ側の溝壁面６ｂをタイヤ径方向外側から内側に向かって溝幅が小さくなる傾斜面によって形成したものである。これにより、ブロック７における突出部７ａ側の剛性を高めることができるので、面取り部７ｂの摩耗量をより低減することができる。   FIG. 7 is a side cross-sectional view of a block showing a fourth embodiment of the present invention, in which the groove wall surface 6b on the protruding portion 7a side of the lug groove 6 is inclined so that the groove width decreases from the outer side in the tire radial direction toward the inner side. It is formed by. Thereby, since the rigidity by the side of the protrusion part 7a in the block 7 can be improved, the abrasion loss of the chamfering part 7b can be reduced more.

この場合、突出部７ｂ側の溝壁面６ｂをタイヤ径方向に対する傾斜角度θが１゜以上１０゜以下になるように形成することにより、剛性を過剰に高めることなく摩耗量の低減効果を十分に得ることができる。   In this case, by forming the groove wall surface 6b on the projecting portion 7b side so that the inclination angle θ with respect to the tire radial direction is not less than 1 ° and not more than 10 °, the effect of reducing the wear amount can be sufficiently obtained without excessively increasing the rigidity. Can be obtained.

また、突出部側の溝壁面６ｂを、突出部７ａの面取り長さＬ1 が長くなると、タイヤ径方向に対する傾斜角度θが大きくなるように形成すれば、突出部７ａ側の剛性を突出部７ａの幅方向に亘って面取り長さＬ1 に応じた適正な剛性にすることができ、操縦安定性の向上に効果的である。   Further, if the groove wall surface 6b on the projecting portion side is formed so that the inclination angle θ with respect to the tire radial direction becomes larger as the chamfer length L1 of the projecting portion 7a becomes longer, the rigidity on the projecting portion 7a side is increased. Appropriate rigidity according to the chamfering length L1 can be obtained in the width direction, which is effective in improving the steering stability.

本発明の実施例１〜６、従来例、比較例について、それぞれ耐偏摩耗性の試験を行ったところ、図８に示す結果が得られた。ここでは、従来例としてブロックの突出部に面取り部を有しないタイヤを用い、比較例１〜３及び実施例１〜６にはブロックの突出部に面取り部を有するタイヤを用いた。この場合、比較例１には面取り長さＬ1 が突出部の幅方向に亘って同一長さ（１．０ｍｍ）で、面取り深さＨが１．０ｍｍのものを用いた。比較例２〜３及び実施例１〜６には、面取り長さＬ1 をブロック７の蹴り出し側端部から踏み込み側端部までの長さＬ2 で除した値（Ｌ1 ／（Ｌ1 ＋Ｌ2 ））がそれぞれ０．０１、０．２５、０．０２、０．１０、０．２０、０．１０、０．１０、０．１０で、面取り深さＨがそれぞれ１．０ｍｍのものを用いた。このうち、実施例４には、第２の実施形態のように面取り部７ｂをタイヤ周方向一端Ｐ1 から他端Ｐ2 に亘ってタイヤ径方向外側に凸状をなす曲線状に形成したものを用い、実施例４以外は直線状に形成したものを用いた。また、実施例５には、第３の実施形態のようにラグ溝６の底部に底上げ部６ｃを設けたもの、実施例６には、第４の実施形態のようにラグ溝６における突出部７ａ側の溝壁面６ｂを傾斜面によって形成したものを用いた。尚、本試験は、タイヤサイズ２０５／６０Ｒ１６、空気圧２３０ｋＰａのタイヤを実車に装着して行った。   When Examples 1 to 6, the conventional example, and the comparative example of the present invention were tested for uneven wear resistance, the results shown in FIG. 8 were obtained. Here, the tire which does not have a chamfering part in the protrusion part of a block was used as a prior art example, and the tire which has a chamfering part in the protrusion part of a block was used for Comparative Examples 1-3 and Examples 1-6. In this case, in Comparative Example 1, a chamfering length L1 having the same length (1.0 mm) in the width direction of the protruding portion and a chamfering depth H of 1.0 mm was used. In Comparative Examples 2-3 and Examples 1-6, the value (L1 / (L1 + L2)) obtained by dividing the chamfering length L1 by the length L2 from the kicking side end to the stepping side end of the block 7 Those having 0.01, 0.25, 0.02, 0.10, 0.20, 0.10, 0.10, and 0.10, respectively, and chamfering depths H of 1.0 mm were used. Of these, in Example 4, as in the second embodiment, the chamfered portion 7b is formed in a curved shape that protrudes outward in the tire radial direction from one end P1 to the other end P2 in the tire circumferential direction. Except for Example 4, those formed linearly were used. Further, in Example 5, the bottom raised portion 6c is provided at the bottom of the lug groove 6 as in the third embodiment, and in Example 6, the protruding portion in the lug groove 6 as in the fourth embodiment. What formed the groove wall surface 6b by the side of 7a by the inclined surface was used. In this test, tires having a tire size of 205 / 60R16 and an air pressure of 230 kPa were mounted on an actual vehicle.

この試験では、一般道を２００００ｋｍ走行した後、ブロックの蹴り出し側端部と踏み込み側端部の摩耗量の差を測定してその逆数を指数化し、従来例を１００として実施例を評価した。この場合、指数の値が１２０以上は優位性があるとして判定した。試験の結果、比較例１〜３は何れも従来例に比べて耐偏摩耗性に優れ、実施例１〜６は何れも比較例１〜３に比べて耐偏摩耗性に優れているという結果が得られた。   In this test, after traveling 20000 km on a general road, the difference in wear amount between the kicking side end and the stepping side end of the block was measured and its reciprocal number was indexed. In this case, it was determined that an index value of 120 or more is superior. As a result of the test, Comparative Examples 1 to 3 are all excellent in uneven wear resistance compared to the conventional example, and Examples 1 to 6 are all excellent in uneven wear resistance compared to Comparative Examples 1 to 3. was gotten.

本発明の第１の実施形態を示す空気入りタイヤの部分正面断面図Partial front sectional view of the pneumatic tire showing the first embodiment of the present invention 空気入りタイヤの部分平面図Partial plan view of pneumatic tire ブロックの平面図Block top view ブロックの側面断面図Side sectional view of block 本発明の第２の実施形態を示すブロックの側面断面図Side surface sectional drawing of the block which shows the 2nd Embodiment of this invention 本発明の第３の実施形態を示すブロックの側面断面図Side surface sectional drawing of the block which shows the 3rd Embodiment of this invention 本発明の第４の実施形態を示すブロックの側面断面図Side surface sectional drawing of the block which shows the 4th Embodiment of this invention 試験結果を示す図Diagram showing test results

符号の説明Explanation of symbols

３…ショルダー部、５…主溝、６…ラグ溝、６ａ，６ｂ…溝壁、６ｃ…底上げ部、７…ブロック、７ａ…突出部、７ｂ…面取り部。   3 ... shoulder part, 5 ... main groove, 6 ... lug groove, 6a, 6b ... groove wall, 6c ... bottom raised part, 7 ... block, 7a ... projecting part, 7b ... chamfered part.

Claims (10)

タイヤ周方向に延びる主溝と、タイヤ幅方向に延びるラグ溝と、主溝及びラグ溝によって区画形成されるブロックとを備え、ブロックの蹴り出し側端部にブロックの幅方向中央側が幅方向両側よりもタイヤ周方向に突出する突出部を設けた空気入りタイヤにおいて、
前記ブロックの接地面と突出部側のラグ溝の溝壁面との間に面取り部を設け、
面取り部を、そのタイヤ周方向一端から他端までの面取り長さが突出部の幅方向両側よりも幅方向中央側が長くなるように形成するとともに、
面取り部を、面取り長さの最も長くなる部分の面取り長さが、その部分におけるブロックの蹴り出し側端部から踏み込み側端部までの長さの２％以上２０％以下になるように形成し、
突出部の蹴り出し側端部をその幅方向中央側から両端側に亘って曲線状をなすように形成した
ことを特徴とする空気入りタイヤ。 A main groove extending in the tire circumferential direction; a lug groove extending in the tire width direction; and a block defined by the main groove and the lug groove. In a pneumatic tire provided with a protruding portion that protrudes more in the tire circumferential direction than
A chamfered portion is provided between the grounding surface of the block and the groove wall surface of the lug groove on the protruding side,
The chamfered portion is formed such that the chamfered length from one end to the other end in the tire circumferential direction is longer on the center side in the width direction than on both sides in the width direction of the protruding portion ,
The chamfered portion is formed so that the chamfered length of the portion with the longest chamfered length is 2% or more and 20% or less of the length from the kicking side end portion of the block to the stepping side end portion in that portion. ,
A pneumatic tire characterized in that the kick-out side end portion of the protruding portion is formed in a curved shape from the center side in the width direction to both end sides . 前記面取り部を、面取り長さの最も長くなる部分の蹴り出し側端部におけるタイヤ径方向の面取り深さが１ｍｍ以上２ｍｍ以下になるように形成した
ことを特徴とする請求項１記載の空気入りタイヤ。 The chamfered portion, the air according to claim 1 Symbol mounting chamfer length becomes longest portion kicking the tire radial direction of the chamfer depth at the side end portion out of the is characterized in that it is formed so as to 1mm or 2mm or less Enter tire. 前記面取り部を、そのタイヤ周方向一端から他端に亘ってタイヤ径方向外側に凸状をなす曲線状に形成した
ことを特徴とする請求項１または２記載の空気入りタイヤ。 The pneumatic tire according to claim 1 or 2 , wherein the chamfered portion is formed in a curved shape that protrudes outward in the tire radial direction from one end to the other end in the tire circumferential direction. 前記ラグ溝の底部に、一方の溝壁面から突出部側の他方の溝壁面に向かってタイヤ径方向の溝深さが徐々に浅くなる底上げ部を設けた
ことを特徴とする請求項１、２または３記載の空気入りタイヤ。 The bottom part of the said lug groove was provided with the bottom raising part from which the groove depth of a tire radial direction becomes shallow gradually toward the other groove wall surface by the side of a protrusion from one groove wall surface. Or the pneumatic tire of 3 . 前記底上げ部を、突出部の面取り長さが長くなると、突出部側の溝壁面の溝深さが浅くなるように形成した
ことを特徴とする請求項４記載の空気入りタイヤ。 The pneumatic tire according to claim 4 , wherein the bottom raised portion is formed such that the groove depth of the groove wall surface on the protruding portion side becomes shallower when the chamfer length of the protruding portion becomes longer. 前記ラグ溝における突出部側の溝壁面をタイヤ径方向外側から内側に向かって溝幅が小さくなる傾斜面によって形成した
ことを特徴とする請求項１、２、３、４または５記載の空気入りタイヤ。 The pneumatic wall according to claim 1, 2, 3, 4, or 5, wherein the groove wall surface on the protruding portion side of the lug groove is formed by an inclined surface in which the groove width decreases from the outer side toward the inner side in the tire radial direction. tire. 前記突出部側の溝壁面をタイヤ径方向に対する傾斜角度が１゜以上１０゜以下になるように形成した
ことを特徴とする請求項６記載の空気入りタイヤ。 The pneumatic tire according to claim 6, wherein the groove wall surface on the projecting portion side is formed so that an inclination angle with respect to a tire radial direction is not less than 1 ° and not more than 10 °. 前記突出部側の溝壁面を、突出部の面取り長さが長くなると、タイヤ径方向に対する傾斜角度が大きくなるように形成した
ことを特徴とする請求項６または７記載の空気入りタイヤ。 The pneumatic tire according to claim 6 or 7, wherein the groove wall surface on the projecting portion side is formed such that when the chamfer length of the projecting portion is increased, an inclination angle with respect to the tire radial direction is increased. タイヤ周方向に延びる主溝と、タイヤ幅方向に延びるラグ溝と、主溝及びラグ溝によって区画形成されるブロックとを備え、ブロックの蹴り出し側端部にブロックの幅方向中央側が幅方向両側よりもタイヤ周方向に突出する突出部を設けた空気入りタイヤにおいて、
前記ブロックの接地面と突出部側のラグ溝の溝壁面との間に面取り部を設け、
面取り部を、そのタイヤ周方向一端から他端までの面取り長さが突出部の幅方向両側よりも幅方向中央側が長くなるように形成するとともに、
面取り部を、面取り長さの最も長くなる部分の面取り長さが、その部分におけるブロックの蹴り出し側端部から踏み込み側端部までの長さの２％以上２０％以下になるように形成し、
ラグ溝の底部に、一方の溝壁面から突出部側の他方の溝壁面に向かってタイヤ径方向の溝深さが徐々に浅くなる底上げ部を設け、
底上げ部を、突出部の面取り長さが長くなると、突出部側の溝壁面の溝深さが浅くなるように形成した
ことを特徴とする空気入りタイヤ。 A main groove extending in the tire circumferential direction; a lug groove extending in the tire width direction; and a block defined by the main groove and the lug groove. In a pneumatic tire provided with a protruding portion that protrudes more in the tire circumferential direction than
A chamfered portion is provided between the grounding surface of the block and the groove wall surface of the lug groove on the protruding side,
The chamfered portion is formed such that the chamfered length from one end to the other end in the tire circumferential direction is longer on the center side in the width direction than on both sides in the width direction of the protruding portion,
The chamfered portion is formed so that the chamfered length of the portion with the longest chamfered length is 2% or more and 20% or less of the length from the kicking side end portion of the block to the stepping side end portion in that portion. ,
A bottom raised portion is provided at the bottom of the lug groove so that the groove depth in the tire radial direction gradually decreases from one groove wall surface to the other groove wall surface on the protruding portion side,
A pneumatic tire characterized in that the bottom raised portion is formed such that the groove depth of the groove wall surface on the protruding portion side becomes shallower when the chamfer length of the protruding portion becomes longer . タイヤ周方向に延びる主溝と、タイヤ幅方向に延びるラグ溝と、主溝及びラグ溝によって区画形成されるブロックとを備え、ブロックの蹴り出し側端部にブロックの幅方向中央側が幅方向両側よりもタイヤ周方向に突出する突出部を設けた空気入りタイヤにおいて、
前記ブロックの接地面と突出部側のラグ溝の溝壁面との間に面取り部を設け、
面取り部を、そのタイヤ周方向一端から他端までの面取り長さが突出部の幅方向両側よりも幅方向中央側が長くなるように形成するとともに、
面取り部を、面取り長さの最も長くなる部分の面取り長さが、その部分におけるブロックの蹴り出し側端部から踏み込み側端部までの長さの２％以上２０％以下になるように形成し、
ラグ溝における突出部側の溝壁面をタイヤ径方向外側から内側に向かって溝幅が小さくなる傾斜面によって形成し、
突出部側の溝壁面を、突出部の面取り長さが長くなると、タイヤ径方向に対する傾斜角度が大きくなるように形成した
ことを特徴とする空気入りタイヤ。 A main groove extending in the tire circumferential direction; a lug groove extending in the tire width direction; and a block defined by the main groove and the lug groove. In a pneumatic tire provided with a protruding portion that protrudes more in the tire circumferential direction than
A chamfered portion is provided between the grounding surface of the block and the groove wall surface of the lug groove on the protruding side,
The chamfered portion is formed such that the chamfered length from one end to the other end in the tire circumferential direction is longer on the center side in the width direction than on both sides in the width direction of the protruding portion,
The chamfered portion is formed so that the chamfered length of the portion with the longest chamfered length is 2% or more and 20% or less of the length from the kicking side end portion of the block to the stepping side end portion in that portion. ,
The groove wall surface on the protruding portion side in the lug groove is formed by an inclined surface in which the groove width decreases from the outside in the tire radial direction toward the inside,
A pneumatic tire characterized in that the groove wall surface on the protruding portion side is formed so that the inclination angle with respect to the tire radial direction increases as the chamfer length of the protruding portion increases .
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