JP2012076656A - Agricultural tire - Google Patents
Agricultural tire Download PDFInfo
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- JP2012076656A JP2012076656A JP2010225059A JP2010225059A JP2012076656A JP 2012076656 A JP2012076656 A JP 2012076656A JP 2010225059 A JP2010225059 A JP 2010225059A JP 2010225059 A JP2010225059 A JP 2010225059A JP 2012076656 A JP2012076656 A JP 2012076656A
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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
- B60C11/0311—Patterns comprising tread lugs arranged parallel or oblique to the axis of rotation
- B60C11/0316—Patterns comprising tread lugs arranged parallel or oblique to the axis of rotation further characterised by the groove cross-section
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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
- B60C11/0311—Patterns comprising tread lugs arranged parallel or oblique to the axis of rotation
- B60C2011/0313—Patterns comprising tread lugs arranged parallel or oblique to the axis of rotation directional type
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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
- B60C2200/00—Tyres specially adapted for particular applications
- B60C2200/08—Tyres specially adapted for particular applications for agricultural vehicles
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- Engineering & Computer Science (AREA)
- Mechanical Engineering (AREA)
- Tires In General (AREA)
Abstract
Description
本発明は、農業用タイヤに関する。 The present invention relates to an agricultural tire.
トレッド部のトレッドセンター部からトレッドショルダー部に向けてタイヤ周方向に対して傾斜して延びる複数のラグを有するラグ付き走行体であって、ショルダー端部がセンター端部よりもタイヤ回転方向に対して先に接地する構造が開示されている(特許文献1参照)。 A traveling body with a lug having a plurality of lugs extending obliquely with respect to the tire circumferential direction from the tread center portion of the tread portion toward the tread shoulder portion, wherein the shoulder end portion is closer to the tire rotation direction than the center end portion. A structure for grounding first is disclosed (see Patent Document 1).
近年の農業用タイヤについては、農地だけでなく舗装路での使用機会が増加している。この理由としは、農業経営の集約化により、離れた農地間を移動する必要が生じたことが挙げられる。一方、このことは、従来農業用タイヤにおいては比較的重要視されていなかった、振動や摩耗等の性能の向上が強く求められるようになってきたことを意味する。従って、従来から用いられているタイヤ幅方向に対するラグブロックの傾斜角度が小さいローアングルなパターンではなく、振動低減に有利な、該傾斜角度が大きいハイアングルなパターンが求められる傾向がある。 In recent years, the use of agricultural tires on paved roads as well as farmland has increased. The reason for this is the need to move between distant farmlands due to the consolidation of farm management. On the other hand, this means that there has been a strong demand for improved performance such as vibration and wear, which has not been relatively important in conventional agricultural tires. Therefore, there is a tendency to demand a high-angle pattern having a large inclination angle, which is advantageous for reducing vibration, instead of a low-angle pattern having a small inclination angle of the lug block with respect to the tire width direction conventionally used.
しかしながら、ハイアングルなパターンでは、農業用タイヤに最も必要とされる不整地でのトラクション性能を大きく低下させることとなる。この大きな原因の一つに、ハイアングルなパターンの場合、ラグブロックで掴んだ土壌がタイヤ幅方向に流れ易い、ということが挙げられる。 However, the high-angle pattern greatly reduces the traction performance on rough terrain that is most needed for agricultural tires. One of the major causes is that in the case of a high-angle pattern, the soil grasped by the lug block tends to flow in the tire width direction.
一般的に、土壌のせん断強度は、締め固められた方が高くなり、ラグブロックがこの締め固められた土壌を掻くことでトラクションを発生させることができる。この土壌がタイヤ幅方向に流れ易いということは、トレッド踏面下の土壌が十分に締め固められないということであり、結果として土壌のせん断強度を生かしきれずにトラクション性能が低下する。逆に言えば、ハイアングルなラグブロックでトラクション性能を向上させるためには、トレッド踏面下での土壌の流れを如何に抑制するかが重要となる。 In general, the soil has a higher shear strength, and the rug block can generate traction by scratching the compacted soil. The fact that this soil tends to flow in the tire width direction means that the soil under the tread surface cannot be sufficiently compacted, and as a result, the traction performance is lowered without fully utilizing the shear strength of the soil. In other words, in order to improve traction performance with a high-angle lug block, it is important how to suppress the flow of soil under the tread surface.
うに、 Sea urchin
本発明は、上記事実を考慮して、農業用タイヤにおいて、舗装路における振動を抑制しつつ、農地でのトラクション性能を向上させることを目的とする。 In view of the above facts, an object of the present invention is to improve traction performance on agricultural land while suppressing vibration on a paved road in agricultural tires.
請求項1の発明は、トレッドに設けられた複数のラグブロックと、タイヤ周方向に隣り合う前記ラグブロックの間の溝底、及び前記ラグブロックの踏込み端側の壁部の少なくとも一方に、農地での走行時に前記ラグブロックの間の土壌がタイヤ幅方向外側に流れることを抑制する特異曲率領域と、を有している。 According to the first aspect of the present invention, at least one of the plurality of lug blocks provided on the tread, the groove bottom between the lug blocks adjacent to each other in the tire circumferential direction, and the wall portion on the stepping end side of the lug block is provided on the farmland. And a specific curvature region that suppresses the soil between the lug blocks from flowing to the outside in the tire width direction when traveling at a vehicle.
請求項1に記載の農業用タイヤでは、農地での走行時に、タイヤ周方向に隣り合うラグブロックの間に土壌が入るが、このとき特異曲率領域によって、該土壌がタイヤ幅方向へ流れることが抑制されるので、ラグブロックの踏込み端側での土壌の圧力が増加する。従って、タイヤ幅方向に対するラグブロックの傾斜角度を比較的大きくしても、該ラグブロックの間で土壌を十分に締め固めて、該土壌のせん断強度を向上させることができる。このため、舗装路における振動を抑制しつつ、農地でのトラクション性能を確保することができる。 In the agricultural tire according to claim 1, the soil enters between the lug blocks adjacent to each other in the tire circumferential direction when traveling on the farmland. At this time, the soil may flow in the tire width direction due to the specific curvature region. Since it is suppressed, the pressure of the soil at the stepped-in end side of the lug block increases. Therefore, even if the inclination angle of the lug block with respect to the tire width direction is relatively large, the soil can be sufficiently compacted between the lug blocks and the shear strength of the soil can be improved. For this reason, it is possible to ensure the traction performance on the farmland while suppressing the vibration on the paved road.
請求項2の発明は、請求項1に記載の農業用タイヤにおいて、前記特異曲率領域は、前記踏込み端寄りに形成され、タイヤ周方向に隣り合う前記ラグブロックの間隔の5〜75%のタイヤ周方向長さを有する平坦部又は凹部である。 According to a second aspect of the present invention, in the agricultural tire according to the first aspect, the singular curvature region is formed near the stepping end, and the tire is 5 to 75% of the interval between the lug blocks adjacent in the tire circumferential direction. It is the flat part or recessed part which has the circumferential direction length.
ここで、ラグブロックの間隔に対する平坦部又は凹部のタイヤ周方向長さの割合の下限を5%としたのは、これを下回ると、ラグブロックの踏込み端側で十分な圧力上昇が得られないからである。また上限を75%としたのは、これを上回ると、ラグブロックの蹴出し端側での土壌の圧力が増加して、走行抵抗の増加を招くからである。 Here, the lower limit of the ratio of the length in the tire circumferential direction of the flat portion or the concave portion with respect to the gap between the lug blocks is set to 5%. If the lower limit is not reached, a sufficient pressure increase cannot be obtained on the stepping end side of the lug block. Because. Moreover, the upper limit is set to 75% because if it exceeds this, the pressure of the soil on the kicking end side of the lug block increases, leading to an increase in running resistance.
請求項2に記載の農業用タイヤでは、ラグブロックの踏込み端寄りに形成された適切なタイヤ周方向長さの平坦部又は凹部によって、タイヤ幅方向への土壌の流れを直接的に抑制して、農地でのトラクション性能をより向上させることができる。 In the agricultural tire according to claim 2, the flow of soil in the tire width direction is directly suppressed by a flat portion or a recess having an appropriate tire circumferential direction length formed near the stepped end of the lug block. The traction performance on farmland can be further improved.
請求項3の発明は、請求項1又は請求項2に記載の農業用タイヤにおいて、前記特異曲率領域として、前記溝底及び前記壁部の総面積の10%以上の領域を占めると共に、該溝底を基準とした前記ラグブロックの高さの10%以下の高低差を有する凹凸部を備えている。 According to a third aspect of the invention, in the agricultural tire according to the first or second aspect, the singular curvature region occupies a region of 10% or more of the total area of the groove bottom and the wall portion, and the groove An uneven portion having a height difference of 10% or less of the height of the lug block with respect to the bottom is provided.
ここで、凹凸部が溝底及び壁部の総面積に占める割合を10%以上としたのは、これを下回ると、土壌の流れの抑制効果が不十分となるからである。また凹凸部の高低差を、ラグブロックの高さの10%以下としたのは、これを上回ると、単純な表面加工による実現が難しく、モールド製作等におけるコスト面でのメリットがなくなるからである。 Here, the reason why the unevenness portion occupies 10% or more of the total area of the groove bottom and the wall portion is that if it is less than this, the effect of suppressing the flow of soil becomes insufficient. In addition, the difference in height of the concavo-convex portion is set to 10% or less of the height of the lug block, if it exceeds this, it is difficult to realize by simple surface processing, and there is no cost advantage in mold production or the like. .
請求項3に記載の農業用タイヤでは、表面加工により形成可能な適切な大きさの凹凸部によって、タイヤ幅方向への土壌の流れを抑制して、ゴム量を増やすことなく、農地でのトラクション性能を向上させることができる。
請求項4の発明は、請求項3に記載の農業用タイヤにおいて、前記凹凸部は、タイヤ周方向に連なって形成されている。
In the agricultural tire according to claim 3, the soil traction in the tire width direction is suppressed by an uneven portion having an appropriate size that can be formed by surface processing, and the traction on the farmland is increased without increasing the amount of rubber. Performance can be improved.
According to a fourth aspect of the present invention, in the agricultural tire according to the third aspect, the concavo-convex portion is formed continuously in the tire circumferential direction.
請求項4に記載の農業用タイヤでは、凹凸部がタイヤ周方向に連なっているので、タイヤ幅方向への土壌の流れをより一層抑制することができる。 In the agricultural tire according to claim 4, since the uneven portions are continuous in the tire circumferential direction, the flow of soil in the tire width direction can be further suppressed.
以上説明したように、本発明に係る請求項1に記載の農業用タイヤによれば、農業用タイヤにおいて、舗装路における振動を抑制しつつ、農地でのトラクション性能を向上させることができる、という優れた効果が得られる。 As described above, according to the agricultural tire according to claim 1 of the present invention, in the agricultural tire, it is possible to improve the traction performance on the farmland while suppressing the vibration on the paved road. Excellent effect is obtained.
請求項2に記載の農業用タイヤによれば、タイヤ幅方向への土壌の流れを直接的に抑制して、農地でのトラクション性能をより向上させることができる、という優れた効果が得られる。 According to the agricultural tire of the second aspect, it is possible to obtain an excellent effect that the soil flow in the tire width direction can be directly suppressed and the traction performance on the farmland can be further improved.
請求項3に記載の農業用タイヤによれば、ゴム量を増やすことなく、農地でのトラクション性能を向上させることができる、という優れた効果が得られる。 According to the agricultural tire of the third aspect, an excellent effect is obtained that the traction performance on the farmland can be improved without increasing the amount of rubber.
請求項4に記載の農業用タイヤによれば、タイヤ幅方向への土壌の流れをより一層抑制することができる、という優れた効果が得られる。 According to the agricultural tire of the fourth aspect, an excellent effect is obtained that the flow of soil in the tire width direction can be further suppressed.
[第1実施形態]
図1において、本実施の形態に係る農業用タイヤ10は、複数のラグブロック12と、特異曲率領域の一例たる平坦部14(図2)又は凹部15(図3)とを有している。
[First Embodiment]
In FIG. 1, the agricultural tire 10 according to the present embodiment has a plurality of lug blocks 12 and a flat portion 14 (FIG. 2) or a concave portion 15 (FIG. 3) as an example of a specific curvature region.
複数のラグブロック12は、トレッド16に設けられ、例えばタイヤ周方向に向かって、タイヤ幅方向の両側に交互に配列されている(図6参照)。各々のラグブロック12は、タイヤ幅方向に対してタイヤ回転方向前方(矢印F方向)に傾斜している。 The plurality of lug blocks 12 are provided on the tread 16, and are alternately arranged on both sides in the tire width direction, for example, in the tire circumferential direction (see FIG. 6). Each lug block 12 is inclined forward in the tire rotation direction (arrow F direction) with respect to the tire width direction.
タイヤ周方向に隣り合うラグブロック12の間には、谷間となる溝底18が形成されており、ラグブロック12の幅寸法は、例えば該溝底18側からタイヤ径方向外側に向かって漸減している。即ち、溝底18におけるラグブロック12の幅寸法W1よりも、タイヤ径方向の外側端におけるラグブロック12の幅寸法W2の方が小さくなっている。換言すれば、ラグブロック12における踏込み端12A側の壁部12Bは、タイヤ径方向内側に向かって、タイヤ回転方向前方(矢印F方向)側に裾野状に形成されている。またラグブロック12における蹴出し端12C側の壁部12Dは、タイヤ径方向内側に向かって、タイヤ回転方向後方(矢印R方向)側に裾野状に形成されている。 A groove bottom 18 that forms a valley is formed between the lug blocks 12 adjacent to each other in the tire circumferential direction, and the width dimension of the lug block 12 gradually decreases from the groove bottom 18 side toward the outer side in the tire radial direction, for example. ing. That is, the width dimension W2 of the lug block 12 at the outer end in the tire radial direction is smaller than the width dimension W1 of the lug block 12 at the groove bottom 18. In other words, the wall portion 12B on the step-in end 12A side of the lug block 12 is formed in a skirt shape on the front side in the tire rotation direction (arrow F direction) toward the inner side in the tire radial direction. Further, the wall portion 12D on the side of the kicking end 12C in the lug block 12 is formed in a skirt shape on the rear side in the tire rotation direction (arrow R direction) side toward the inner side in the tire radial direction.
ラグブロック12のタイヤ幅方向中央側の端部12Eは、タイヤ周方向において、他のラグブロック12のタイヤ幅方向中央側の端部12Eと一部重なるように配置されている。これにより、舗装路走行時の振動を低減できるようになっている。 The end 12E on the center side in the tire width direction of the lug block 12 is arranged so as to partially overlap the end portion 12E on the center side in the tire width direction of the other lug block 12 in the tire circumferential direction. Thereby, the vibration at the time of pavement running can be reduced.
次に、図1,図2において、平坦部14は、例えばタイヤ周方向に隣り合うラグブロック12の間の溝底18、及びラグブロック12の踏込み端12A側の壁部12Bの少なくとも一方に設けられ、農地での走行時にラグブロック12の間の土壌がタイヤ幅方向外側に流れることを抑制する特異曲率領域である。 Next, in FIGS. 1 and 2, the flat portion 14 is provided, for example, on at least one of the groove bottom 18 between the lug blocks 12 adjacent to each other in the tire circumferential direction and the wall portion 12B on the stepping end 12A side of the lug block 12. It is a specific curvature region that suppresses the soil between the lug blocks 12 from flowing outward in the tire width direction when traveling on farmland.
図1において、平坦部14は、例えば溝底18の踏込み端12A寄りに形成され、タイヤ周方向に隣り合うラグブロック12の間隔Lの5〜75%のタイヤ周方向長さL1を有している。本実施形態では、平坦部14は、ラグブロック12の踏込み端12A側の壁部12Bの下端からタイヤ回転方向前方(矢印F方向)側に延びている。なお平坦部14を、ラグブロック12から離れた位置に形成したり、ラグブロック12の踏込み端12A側の壁部12Bにのみ形成したり、該壁部12Bから溝底18にかけて形成したりしてもよい。 In FIG. 1, the flat portion 14 is formed, for example, near the stepping end 12 </ b> A of the groove bottom 18, and has a tire circumferential direction length L <b> 1 that is 5 to 75% of an interval L between adjacent lug blocks 12 in the tire circumferential direction. Yes. In the present embodiment, the flat portion 14 extends from the lower end of the wall portion 12B on the stepping end 12A side of the lug block 12 to the front side in the tire rotation direction (arrow F direction). The flat portion 14 is formed at a position away from the lug block 12, formed only on the wall portion 12 </ b> B on the stepping end 12 </ b> A side of the lug block 12, or formed from the wall portion 12 </ b> B to the groove bottom 18. Also good.
ここで、ラグブロック12の間隔Lに対する平坦部14のタイヤ周方向長さL1の割合の下限を5%としたのは、これを下回ると、ラグブロック12の踏込み端12A側で十分な圧力上昇が得られないからである。また上限を75%としたのは、これを上回ると、ラグブロック12の蹴出し端12C側での土壌の圧力が増加して、走行抵抗の増加を招くからである。なお、ラグブロック12の間隔Lとは、トレッド端Tでの、一方のラグブロック12の蹴出し端12Cと、他方のラグブロック12の踏込み端12Aとのタイヤ周方向距離である。 Here, the lower limit of the ratio of the tire circumferential direction length L1 of the flat portion 14 to the interval L between the lug blocks 12 is set to 5%. If the lower limit is less than this, the pressure rises sufficiently on the stepping end 12A side of the lug block 12 It is because it cannot be obtained. Further, the upper limit is set to 75% because if the upper limit is exceeded, the pressure of the soil on the side of the kicking end 12C of the lug block 12 increases, resulting in an increase in running resistance. The interval L between the lug blocks 12 is a tire circumferential direction distance between the kicking end 12C of one lug block 12 and the stepping end 12A of the other lug block 12 at the tread end T.
ここで、トレッド端Tとは、JATMA(日本自動車タイヤ協会)が発行する2010年度版のYEAR BOOKに規定されている標準リムに農業用タイヤ10を装着し、該YEAR BOOKでの適用サイズ・プライレーティングにおける最大荷重に対応する空気圧(最大空気圧)の100%を内圧として充填し、最大荷重を負荷したときのタイヤ幅方向最外の接地部分を指す。なお、使用地又は製造地においてTRA規格、ETRTO規格が適用される場合は、各々の規格に従う。 Here, the tread end T means that an agricultural tire 10 is mounted on a standard rim defined in the 2010 edition YEAR BOOK issued by JATMA (Japan Automobile Tire Association), and the applicable size / ply in the YEAR BOOK Fills 100% of the air pressure (maximum air pressure) corresponding to the maximum load in the rating as the internal pressure, and indicates the outermost contact portion in the tire width direction when the maximum load is applied. In addition, when TRA standard and ETRTO standard are applied in a use place or a manufacturing place, it follows each standard.
図1に示される例では、平坦部14は、隣り合うラグブロック12の間のトレッド端T側に寄った位置に1箇所だけ形成されている。また図4,図5に示される例では、凹部15は、比較的細幅に設定されると共に、隣り合うラグブロック12の間に、タイヤ幅方向に離間して、2箇所ずつ形成されている。この場合、各凹部15のタイヤ周方向長さL1は一定でもよいし、また上記したラグブロック12の間隔Lに対する割合の範囲内で適宜変化していてもよい。凹部15の幅についても、任意に設定することができる。 In the example shown in FIG. 1, only one flat portion 14 is formed at a position close to the tread end T side between adjacent lug blocks 12. Moreover, in the example shown by FIG. 4, FIG. 5, while the recessed part 15 is set comparatively narrowly, it spaced apart in the tire width direction between the adjacent lug blocks 12, and is formed in two places. . In this case, the tire circumferential direction length L1 of each recess 15 may be constant, or may be appropriately changed within the range of the ratio to the interval L of the lug block 12 described above. The width of the recess 15 can also be set arbitrarily.
この平坦部14の構成は、図3における凹部15にも適用される。この凹部15も特異曲率領域であるが、タイヤ幅方向断面において平坦部14(図2)よりも曲率が大きく(曲率半径が小さく)設定されている。 The configuration of the flat portion 14 is also applied to the concave portion 15 in FIG. The concave portion 15 is also a specific curvature region, but is set to have a larger curvature (a smaller radius of curvature) than the flat portion 14 (FIG. 2) in the cross section in the tire width direction.
(作用)
本実施形態は、上記のように構成されており、以下その作用について説明する。図1から図3において、本実施形態に係る農業用タイヤ10では、農地での走行時に、タイヤ周方向に隣り合うラグブロック12の間に土壌が入るが、このとき特異曲率領域である平坦部14又は凹部15によって、該土壌がタイヤ幅方向へ流れることが抑制されるので、ラグブロック12の踏込み端12A側での土壌の圧力が増加する。従って、タイヤ幅方向に対するラグブロック12の傾斜角度を比較的大きくしても、該ラグブロック12の間で土壌を十分に締め固めて、該土壌のせん断強度を向上させることができる。このため、舗装路における振動を抑制しつつ、農地でのトラクション性能を確保することができる。特に、平坦部14又は凹部15が、ラグブロック12の踏込み端12A寄りに形成され、かつ適切なタイヤ周方向長さを有しているので、タイヤ幅方向への土壌の流れを直接的に抑制して、農地でのトラクション性能をより向上させることができる。
(Function)
This embodiment is configured as described above, and the operation thereof will be described below. In FIG. 1 to FIG. 3, in the agricultural tire 10 according to the present embodiment, soil enters between the lug blocks 12 adjacent to each other in the tire circumferential direction when traveling on the farmland. Since the soil or the recess 15 prevents the soil from flowing in the tire width direction, the pressure of the soil on the stepping end 12A side of the lug block 12 increases. Therefore, even if the inclination angle of the lug block 12 with respect to the tire width direction is relatively large, the soil can be sufficiently compacted between the lug blocks 12 and the shear strength of the soil can be improved. For this reason, it is possible to ensure the traction performance on the farmland while suppressing the vibration on the paved road. In particular, since the flat portion 14 or the concave portion 15 is formed near the stepping end 12A of the lug block 12 and has an appropriate tire circumferential direction length, the flow of soil in the tire width direction is directly suppressed. Thus, the traction performance on the farmland can be further improved.
[第2実施形態]
図6,図7において、本実施の形態に係る農業用タイヤ20では、特異曲率領域として、溝底18及び壁部12Bの総面積の10%以上の領域を占めると共に、該溝底18を基準としたラグブロック12の高さHの10%以下の高低差を有する凹凸部24を備えている。
[Second Embodiment]
6 and 7, in the agricultural tire 20 according to the present embodiment, the specific curvature region occupies a region of 10% or more of the total area of the groove bottom 18 and the wall portion 12B, and the groove bottom 18 is used as a reference. The rugged block 24 having a height difference of 10% or less of the height H of the lug block 12 is provided.
ここで、凹凸部24が溝底18及び壁部12Bの総面積に占める割合を10%以上としたのは、これを下回ると、土壌の流れの抑制効果が不十分となるからである。また凹凸部24の高低差を、ラグブロック12の高さHの10%以下としたのは、これを上回ると、単純な表面加工による実現が難しく、モールド製作等におけるコスト面でのメリットがなくなるからである。ここで、「総面積」とは、トレッド16を平面状に展開した際における、トレッド平面視での溝底18及び壁部12Bの面積の総合計をいう。 Here, the reason why the unevenness portion 24 occupies 10% or more of the total area of the groove bottom 18 and the wall portion 12B is that if it is less than this, the effect of suppressing the flow of soil becomes insufficient. Moreover, if the height difference of the concavo-convex portion 24 is set to 10% or less of the height H of the lug block 12, if it exceeds this, it is difficult to realize by simple surface processing, and there is no cost advantage in mold production or the like. Because. Here, the “total area” refers to a total sum of the areas of the groove bottom 18 and the wall portion 12 </ b> B in the tread plan view when the tread 16 is developed in a planar shape.
凹凸部24は、例えば断面波形に形成され、ラグブロック12の踏込み端12A側の壁部12Bから溝底18へ、タイヤ周方向に連なって形成されている。なお、図6に示されるように、この凹凸部24は、ラグブロック12の蹴出し端12C側の壁部12Dには形成されていない。蹴出し端12C側の壁部12Dにおいて、タイヤ幅方向外側への土壌の流れを抑制すると、該蹴出し端12C側での土壌の圧力が増加し、走行抵抗の増加を招くからである。 The concavo-convex portion 24 is formed in, for example, a corrugated cross section, and is formed continuously from the wall portion 12B on the stepping end 12A side of the lug block 12 to the groove bottom 18 in the tire circumferential direction. As shown in FIG. 6, the uneven portion 24 is not formed on the wall portion 12 </ b> D on the side of the kicking end 12 </ b> C of the lug block 12. This is because if the soil flow toward the outer side in the tire width direction is suppressed in the wall portion 12D on the side of the kick-out end 12C, the pressure of the soil on the side of the kick-out end 12C increases, leading to an increase in running resistance.
なお、凹凸部24は、タイヤ周方向に連なるものに限られず、タイヤ周方向に断続的に配置されたものでもよい。また凹凸部24の断面形状は、図示されるような円弧状の波形には限られず、矩形状や台形状の波形であってもよい。 In addition, the uneven | corrugated | grooved part 24 is not restricted to what continues in a tire circumferential direction, The thing arrange | positioned intermittently in a tire circumferential direction may be sufficient. The cross-sectional shape of the concavo-convex portion 24 is not limited to an arcuate waveform as shown in the figure, and may be a rectangular or trapezoidal waveform.
他の部分については、第1実施形態と同様であるので、同一の部分には図面に同一の符号を付し、説明を省略する。 Since other parts are the same as those in the first embodiment, the same parts are denoted by the same reference numerals in the drawings, and the description thereof is omitted.
(作用)
本実施形態は、上記のように構成されており、以下その作用について説明する。図6,図7において、本実施形態に係る農業用タイヤ20では、表面加工により形成可能な適切な大きさの凹凸部24によって、ゴム量を増やすことなく、タイヤ幅方向への土壌の流れを抑制して、農地でのトラクション性能を向上させることができる。この凹凸部24は、タイヤ周方向に連なっているので、タイヤ幅方向への土壌の流れをより一層抑制することが可能である。
(Function)
This embodiment is configured as described above, and the operation thereof will be described below. 6 and 7, in the agricultural tire 20 according to the present embodiment, the uneven flow portion 24 of an appropriate size that can be formed by surface processing allows the flow of soil in the tire width direction without increasing the amount of rubber. It can suppress and can improve the traction performance in farmland. Since the uneven portion 24 is continuous in the tire circumferential direction, the flow of soil in the tire width direction can be further suppressed.
なお、上記した第1実施形態と第2実施形態とを組み合わせることも可能である。この場合、凹凸部24(図6)を形成する面積割合の基準となる、溝底18及び壁部12Bの総面積は、平坦部14又は凹部15(図1から図3)が占める領域を除いて算出される。 It is also possible to combine the first embodiment and the second embodiment described above. In this case, the total area of the groove bottom 18 and the wall portion 12B, which is the basis of the area ratio for forming the uneven portion 24 (FIG. 6), excludes the region occupied by the flat portion 14 or the recessed portion 15 (FIGS. 1 to 3). Is calculated.
図6には、ラグブロック12が、タイヤ赤道面CLの両側に2対ずつ描かれているが、該ラグブロック12は、タイヤ全周に形成されるものである。図1におけるラグブロック12と、平坦部14又は凹部15も、タイヤ全周に形成される。 In FIG. 6, two pairs of lug blocks 12 are drawn on both sides of the tire equatorial plane CL. The lug blocks 12 are formed on the entire circumference of the tire. The lug block 12 in FIG. 1 and the flat part 14 or the recessed part 15 are also formed in the whole tire periphery.
また特異曲率領域の例として、平坦部14、凹部15及び凹凸部24を挙げたが、特異曲率領域はこれらに限られるものではなく、タイヤ幅方向への土壌の流れを抑制できるものであれば、どのような形状の領域であってもよい。 Moreover, although the flat part 14, the recessed part 15, and the uneven | corrugated | grooved part 24 were mentioned as an example of a peculiar curvature area | region, a peculiar curvature area | region is not restricted to these, As long as the flow of the soil to a tire width direction can be suppressed. Any shape region may be used.
ここで、「特異曲率領域」とは、溝底18の本来の輪郭(実線及び破線)や、ラグブロック12の踏込み端12A側の壁部12Bの本来の輪郭(図示せず)に対して、明らかに異なる曲率を有する領域を意味する。 Here, the “singular curvature region” refers to the original contour (solid line and broken line) of the groove bottom 18 and the original contour (not shown) of the wall portion 12B on the stepping end 12A side of the lug block 12. It means a region with a clearly different curvature.
具体的には、図2に示されるように、溝底18の輪郭は、本来タイヤ赤道面CL側からタイヤ幅方向外側に向かうに従って、次第にタイヤ径方向内側に落ち込んでいるが、第1実施形態に係る平坦部14や凹部15では、このような落ち込みがない。この平坦部14や凹部15は、溝底18を部分的に底上げしたものと捉えることができる。また図1に示されるように、溝底18及び壁部12Bは、本来凹凸のない平滑面として形成されているが、第2実施形態に係る凹凸部24は文字通り平滑面ではない。このように、平坦部14、凹部15及び凹凸部24は、各々が形成される部位の本来の輪郭とは明らかに異なる曲率を有する領域となっている。 Specifically, as shown in FIG. 2, the contour of the groove bottom 18 gradually falls to the inner side in the tire radial direction from the tire equatorial plane CL side toward the outer side in the tire width direction. In the flat part 14 and the recessed part 15 which concern on, there is no such depression. The flat portion 14 and the concave portion 15 can be regarded as the groove bottom 18 partially raised. As shown in FIG. 1, the groove bottom 18 and the wall portion 12 </ b> B are originally formed as smooth surfaces without irregularities, but the irregularities 24 according to the second embodiment are not literally smooth surfaces. Thus, the flat part 14, the recessed part 15, and the uneven | corrugated | grooved part 24 are area | regions which have a curvature obviously different from the original outline of the site | part in which each is formed.
(試験例)
表1に示される仕様の従来例と実施例1〜3に係るタイヤについて、トラクション性能の試験として、牽引力を比較した。試験条件は、次の通りである。
タイヤサイズ:AGR 710/70R42
内圧:160kPa
1本のタイヤに作用する荷重:55kN(5600kgf)
路面:草地と耕地
(Test example)
The traction force was compared as a traction performance test for the conventional example of the specification shown in Table 1 and the tires according to Examples 1 to 3. The test conditions are as follows.
Tire size: AGR 710 / 70R42
Internal pressure: 160 kPa
Load acting on one tire: 55kN (5600kgf)
Road surface: grassland and arable land
表1における牽引力は、草地における従来例の牽引力と、耕地における従来例の牽引力とを、夫々100とした指数で示されており、数値が大きいほど良好な結果であることを示している。この結果によれば、実施例1〜3は、草地及び耕地の何れにおいても、従来例を上回っており、良好なトラクション性能を有することがわかった。 The traction force in Table 1 is indicated by an index in which the traction force of the conventional example in the grassland and the traction force of the conventional example in the cultivated land are each 100, and the larger the value, the better the result. According to this result, it was found that Examples 1 to 3 exceeded the conventional example in both grassland and arable land, and had good traction performance.
10 農業用タイヤ
12 ラグブロック
12A 踏込み端
12B 壁部
14 平坦部(特異曲率領域)
15 凹部(特異曲率領域)
16 トレッド
18 溝底
20 農業用タイヤ
24 凹凸部(特異曲率領域)
CL タイヤ赤道面
L 隣り合うラグブロックの間隔
L1 流動抑制手段のタイヤ周方向長さ
DESCRIPTION OF SYMBOLS 10 Agricultural tire 12 Lug block 12A Depression end 12B Wall part 14 Flat part (singular curvature area)
15 Concavity (singular curvature region)
16 Tread 18 Groove bottom 20 Agricultural tire 24 Concavity and convexity (singular curvature region)
CL tire equator plane L interval between adjacent lug blocks L1 tire circumferential direction length of flow suppressing means
Claims (4)
タイヤ周方向に隣り合う前記ラグブロックの間の溝底、及び前記ラグブロックの踏込み端側の壁部の少なくとも一方に、農地での走行時に前記ラグブロックの間の土壌がタイヤ幅方向外側に流れることを抑制する特異曲率領域と、
を有する農業用タイヤ。 A plurality of lug blocks provided in the tread;
At least one of the groove bottom between the lug blocks adjacent to each other in the tire circumferential direction and the wall portion on the stepping end side of the lug block flows the soil between the lug blocks outward in the tire width direction when traveling on farmland. A singular curvature region that suppresses this,
Agricultural tire having.
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Cited By (2)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
CN108349317A (en) * | 2015-10-29 | 2018-07-31 | 株式会社普利司通 | Agricultural tire |
IT202200014134A1 (en) * | 2022-07-04 | 2024-01-04 | Trelleborg Wheel Sys Italia Spa | TYRE FOR VEHICLE WHEELS AND RESPECTIVE TREAD WITH SELF-CLEANING FUNCTION |
Citations (3)
Publication number | Priority date | Publication date | Assignee | Title |
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JPH02204107A (en) * | 1989-01-31 | 1990-08-14 | Ohtsu Tire & Rubber Co Ltd :The | Lug-fitted rubber tire for argicultual machinery |
JPH0834209A (en) * | 1994-07-21 | 1996-02-06 | Bridgestone Corp | Pneumatic tire with lug |
JP2007168684A (en) * | 2005-12-26 | 2007-07-05 | Sumitomo Rubber Ind Ltd | Tire with lug |
-
2010
- 2010-10-04 JP JP2010225059A patent/JP5676202B2/en not_active Expired - Fee Related
Patent Citations (3)
Publication number | Priority date | Publication date | Assignee | Title |
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JPH02204107A (en) * | 1989-01-31 | 1990-08-14 | Ohtsu Tire & Rubber Co Ltd :The | Lug-fitted rubber tire for argicultual machinery |
JPH0834209A (en) * | 1994-07-21 | 1996-02-06 | Bridgestone Corp | Pneumatic tire with lug |
JP2007168684A (en) * | 2005-12-26 | 2007-07-05 | Sumitomo Rubber Ind Ltd | Tire with lug |
Cited By (4)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
CN108349317A (en) * | 2015-10-29 | 2018-07-31 | 株式会社普利司通 | Agricultural tire |
CN108349317B (en) * | 2015-10-29 | 2020-07-14 | 株式会社普利司通 | Agricultural tire |
IT202200014134A1 (en) * | 2022-07-04 | 2024-01-04 | Trelleborg Wheel Sys Italia Spa | TYRE FOR VEHICLE WHEELS AND RESPECTIVE TREAD WITH SELF-CLEANING FUNCTION |
WO2024009171A1 (en) * | 2022-07-04 | 2024-01-11 | Yokohama Tws Societa' Per Azioni | Tire for vehicle wheels and respective tread with self-cleaning function |
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