JP4293427B2 - Pneumatic tire - Google Patents

Description

【００２３】
耐久性評価では、実施例、比較例２のタイヤを小型トラックに装着して、一般路を所定の距離走行後、サイドウォール部の損傷の程度を目視で確認した。結果を表２に示す。表１、表２によれば、本発明のタイヤは、乗り心地及び耐久性において優れている。
【００２４】
【表２】

【００２５】
【発明の効果】
以上の通り、本発明の空気入りタイヤにおいて、サイドウォール表面の所定の位置にサイドプロテクターを設け、さらに、接地端と該サイドプロテクターとの間にタイヤ周方向に連続して連なる複数のリブを備えた構造とした。その結果、該リブによりタイヤの撓みが促進され、路面からの衝撃が吸収され乗り心地が改善できる。
【図面の簡単な説明】
【図１】本発明に係る空気入りタイヤの概略断面図である。
【図２】突条及びリブの拡大断面図である。
【符号の説明】
２ ビードコア
３ カーカス
４ ベルト層
５ トレッドゴム
６ サイドウォールゴム
８ 突条
９ リブ
Ｒ１ 第１環状領域
Ｒ２ 第２環状領域[0001]
BACKGROUND OF THE INVENTION
The present invention relates to protection of a side portion of a pneumatic tire and improvement of the riding comfort of the tire.
[0002]
[Prior art]
Since the sidewall rubber of the tire is thinner than the tread rubber, when running on rough terrain, there is a high possibility that the stone will hit and be damaged such as cracks. Therefore, there are tires provided with protrusions or protrusions called side protectors on the sidewall portions of the tire, and an example of such a pneumatic tire is a pneumatic tire disclosed in Patent Document 1.
[0003]
[Patent Document 1]
Japanese Unexamined Patent Publication No. 2000-16032 (pages 1 to 3, FIGS. 1 and 2)
[0004]
[Problems to be solved by the invention]
Even in a small truck delivered to a convenience store, when entering or leaving the store or parking in front of the store, the sidewall portion may come into contact with the curb, the step that separates the sidewalk and the roadway, and the like may be damaged. Therefore, it is necessary to provide a side protector.
[0005]
When the side protector is provided, the sidewall portion becomes thicker and harder than necessary, so that the impact from the road surface irregularities and protrusions cannot be sufficiently absorbed, and riding comfort may deteriorate. In particular, when used in business conditions such as delivery to a convenience store, even when traveling on urban roads with many road surface irregularities and protrusions such as road construction traces, delicate foods are delivered to prevent collapse of goods. From such viewpoints, it is important to secure ride comfort and protect the transported goods.
[0006]
Accordingly, an object of the present invention is to improve impact comfort by improving shock absorption in a pneumatic tire provided with a side protector, and to prevent a load from collapsing or damaging a transported item.
[0007]
[Means for Solving the Problems]
As a result of diligent studies to solve the above problems, the present invention has a pair of bead cores, a carcass wound around the bead core to form a toroidal shape, and a belt layer disposed on the outer side in the tire radial direction of the crown portion of the carcass. In a pneumatic tire provided with a tread rubber disposed on the outer side in the tire radial direction from the belt layer, and a sidewall rubber disposed on the tire outer side of the side portion of the carcass,
On the surface of the sidewall rubber, the first annular region from 30 mm to 100 mm in the vertical direction from the tire maximum outer diameter surface is provided with one or a plurality of protrusions continuously or intermittently continuous in the tire circumferential direction,
On the surface of the sidewall rubber, a plurality of ribs continuously connected in the tire circumferential direction are provided in the second annular region from the position 30 mm perpendicular to the tire maximum outer diameter surface to the ground contact end ,
The ridges occupy 50% to 100% of the area of the first annular region, the central part of the cross section in the tire radial direction of the ridges is depressed, and the maximum thickness of the ridges is the thickness of the central part. 1.2 mm or more and 1 mm to 5 mm, 3 or more ribs, arranged in the range of 4.5 mm to 12 mm in the tire radial direction, and the rib thickness is 1 mm or more And it was set as the pneumatic tire which is below the maximum thickness of the said protrusion .
[0008]
The inventor has found that the position that is easily damaged by curbstones or the like in urban driving is a position (first annular region) from 30 mm to 100 mm in the vertical direction from the tire maximum outer diameter surface of the sidewall portion. From this knowledge, a protrusion is provided in the first annular region, and an effect as a side protector is achieved. Furthermore, by providing ribs in the second annular region from the position 30 mm perpendicular to the tire's maximum outer diameter surface to the ground contact edge, it is possible to promote bending in the tire radial direction, absorb impact from the road surface, and improve ride comfort. Can improve.
[0010]
In off-road traveling, there are many cases in which protruding foreign objects such as stones are pierced, but according to another knowledge of the inventor, the curb stones often rub the side wall portion according to another knowledge of the inventor. Therefore, the protrusion does not need to be thick enough to prevent the penetration of the protruding foreign matter, and 1 mm to 5 mm is sufficient. Moreover, even if the center part of the tire radial cross section of the ridge is depressed, it is possible to protect the both ends of the tire radial direction, which is the maximum thickness, from being damaged at the initial contact. Further, if the shape is such that the protrusion is applied, it is possible to suppress the rigidity of the sidewall portion from becoming excessively high, which contributes to weight reduction of the tire. Moreover, the stress with respect to a carcass cord from a protrusion is reduced at the time of vulcanization molding.
[0011]
If the number of ribs is three or more, bending can be sufficiently promoted. If the thickness is 1 mm or more and less than the maximum thickness of the protrusion, the rigidity of the rib itself is increased. Riding comfort is not deteriorated.
[0012]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, embodiments of a pneumatic tire according to the present invention will be described with reference to the drawings. FIG. 1 is a schematic cross-sectional view of a pneumatic tire according to the present invention. The pneumatic tire 1 includes a pair of bead cores 2, a carcass 3 wound around the bead core 2 to form a toroidal shape, a reinforcing belt layer 4 disposed on the outer side in the tire radial direction of a crown portion of the carcass 3, and a tire radial direction of the reinforcing belt layer 4 A tread rubber 5 disposed outside and a side wall rubber 6 disposed outside the tire on the side portion of the carcass 3 are provided. On the surface of the tread rubber 5, main grooves 10 continuous in the tire circumferential direction are carved to form ribs 11. Further, a transverse groove (not shown) may be cut and a block (not shown) may be formed on the surface of the tread rubber 5. Note that CL is a tread center line.
[0013]
On the surface of the sidewall rubber 6, a plurality of ridges 8 continuously connected in the tire circumferential direction are provided in a first annular region R1 from 30 mm (H1) to 100 mm (H2) in the vertical direction from the tire maximum outer diameter surface D. I have. Further, a plurality of ribs 9 that are continuously connected in the tire circumferential direction are provided in the second annular region R2 from the position 30 mm in the vertical direction from the tire maximum outer diameter surface D to the ground contact end P.
[0014]
Since the first annular region R1 is the region most easily damaged by curbs when traveling on a small truck in an urban area, an effect as a side protector is provided by providing a plurality of ridges 8 continuously in the tire circumferential direction in the region R1. Play. The protrusion 8 may be either one or a plurality, and may be intermittently extended in the circumferential direction even if it is not continuous.
[0015]
Since the arrangement position of the protrusion 8 as the side protector is limited to the first annular region R1, the rib 9 can be arranged in the second annular region R2 from the first annular region R1 to the grounding end P. Since the cross-sectional shape of the rib 9 is a saw shape so that it can be easily bent, the rib 9 can be bent to absorb the shock when receiving an impact from the road surface. The cross-sectional shape of the rib 9 may be a wave shape or a trapezoidal shape.
[0016]
Furthermore, the shape of the protrusion 8 and the rib 9 is demonstrated with the expanded sectional view of FIG. As described above, since the curb often hits the sidewall 6 when traveling in an urban area, a surface or line contact occurs. Therefore, if the ridge 8 occupies 50% to 100% of the area of the first annular region R <b> 1, the curb hits the ridge 8 first and can be protected without hitting the sidewall 6. If it is less than 50%, the curb may directly hit the sidewall 6 between the ridges 8 and cannot be sufficiently protected.
[0017]
Further, since the protrusion 8 is not required to have a thickness that can prevent the penetration of the protruding foreign matter, the maximum thickness T1 of the protrusion 8 can be set to 1 mm to 5 mm. If the thickness T1 is less than 1 mm, sufficient protection cannot be achieved, and if it exceeds 5 mm, the rigidity becomes high, and even if the ribs 9 are provided, the riding comfort cannot be improved.
[0018]
You may provide the hollow 8a in the center part of the tire radial direction cross section of the protrusion 8. Even if the recess 8a is present, if the thickness T1 of the both end portions 8b is 1.2 times the thickness T3 of the recess 8a, the end portions 8b first hit the curb and protect the sidewalls 6.
[0019]
Further, if the number of the ribs 9 is three or more, the bending can be sufficiently promoted, and the rib 9 is arranged in the range of the length H3 = 4.5 mm to 12 mm (15% to 40% of H1) in the tire radial direction. The thickness T2 of 9 is preferably 1 mm or more and not more than the maximum thickness T1 of the protrusion 8. When the number of the ribs 9 is 2 or less, the bending is not sufficiently promoted. The same applies when the length H3 is less than 4.5 mm and the thickness T2 is less than 1 mm. On the other hand, when the length H3 exceeds 12 mm or the thickness T2 exceeds 5 mm, the rigidity of the rib 9 becomes too high to absorb the impact sufficiently.
[0020]
【Example】
As an example, a pneumatic tire according to the present invention, a tire including only the protrusions 8 as Comparative Example 1, and a tire including neither the protrusions 8 nor the ribs 9 as Comparative Example 2 were manufactured. In Examples and Comparative Example 1, three protrusions having a thickness T1 of 1.2 mm were arranged in a range of 50 mm to 100 mm in the vertical direction from the tire maximum outer diameter surface D. In the example, three ribs having a thickness T3 of 1.2 mm and a tire radial length H3 of 17 mm were provided. All tire sizes were 195 / 85R16.
[0021]
The tires of Examples and Comparative Example 1 were mounted on a small truck, and riding comfort evaluation and durability were performed. Riding comfort evaluation is a driver's feeling evaluation when passing a road surface with unevenness and protrusions. The results are shown in Table 1. In Table 1, the hardness is a feeling evaluation of whether or not the tire feels during running. Passing through large irregularities is a feeling evaluation when a road surface having a length of 15 mm and a height of 15 mm is installed at intervals of 500 mm and a road surface having a length of 10 m is passed at 10 km / h. The small protrusion passage is a feeling evaluation when passing through a hemispherical protrusion whose protrusion amount from the road surface is 10 mm at 40 km / h. The passage of the large protrusion is a feeling evaluation when passing over a hemispherical protrusion having a protrusion amount from the road surface of 20 mm at 40 km / h. In any of the items, ◎ is the best evaluation, and the evaluation becomes worse in the order of ◯, Δ, ×.
[0022]
[Table 1]

[0023]
In the durability evaluation, the tires of Example and Comparative Example 2 were mounted on a small truck, and after traveling on a general road for a predetermined distance, the degree of damage of the sidewall portion was visually confirmed. The results are shown in Table 2. According to Tables 1 and 2, the tire of the present invention is excellent in ride comfort and durability.
[0024]
[Table 2]

[0025]
【The invention's effect】
As described above, in the pneumatic tire of the present invention, a side protector is provided at a predetermined position on the sidewall surface, and further includes a plurality of ribs continuously connected in the tire circumferential direction between the ground contact end and the side protector. Structure. As a result, the bending of the tire is promoted by the rib, the impact from the road surface is absorbed, and the riding comfort can be improved.
[Brief description of the drawings]
FIG. 1 is a schematic sectional view of a pneumatic tire according to the present invention.
FIG. 2 is an enlarged cross-sectional view of ridges and ribs.
[Explanation of symbols]
2 Bead core 3 Carcass 4 Belt layer 5 Tread rubber 6 Side wall rubber 8 Projection 9 Rib R1 First annular region R2 Second annular region

Claims (1)

A pair of bead cores, a carcass wound around the bead core to form a toroidal shape, a belt layer disposed on the outer side in the tire radial direction of the crown portion of the carcass, and a tread rubber disposed on the outer side in the tire radial direction from the belt layer In the pneumatic tire provided with a sidewall rubber disposed on the tire outer side of the side portion of the carcass,
On the surface of the sidewall rubber, the first annular region from 30 mm to 100 mm in the vertical direction from the tire maximum outer diameter surface is provided with one or a plurality of protrusions continuously or intermittently continuous in the tire circumferential direction,
On the surface of the sidewall rubber, a plurality of ribs continuously connected in the tire circumferential direction are provided in the second annular region from the position 30 mm perpendicular to the tire maximum outer diameter surface to the ground contact end ,
The ridges occupy 50% to 100% of the area of the first annular region, the central part of the cross section in the tire radial direction of the ridges is depressed, and the maximum thickness of the ridges is the thickness of the central part. 1.2 mm or more and 1 mm to 5 mm, 3 or more ribs, arranged in the range of 4.5 mm to 12 mm in the tire radial direction, and the rib thickness is 1 mm or more And the pneumatic tire which is below the maximum thickness of the said protrusion .

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