The present invention relates to pneumatic tires.
There has been known a technique for making unevenness present on an outer surface of a side wall portion inconspicuous (Patent Document 1). A plurality of circumferential pattern element arrays in which a plurality of pattern elements having the same contour shape are continuously provided in a tire circumferential direction and a plurality of radial pattern element arrays in which a plurality of pattern elements are continuously provided in a tire radial direction are formed on the side wall portion in Patent Document 1.
[Patent Document 1] Japanese Patent Application Publication No. 2013-71572
In recent years, as demands for environmental protection increase, further weight reduction of tires is required. As an example method of reducing the weight of the tires, it is known to thin down the gauge thickness of the side wall portion. However when the gauge thickness of the side wall portion is thinned down, the unevenness is not formed deeply and it is difficult to improve an appearance of the side wall portion.
In view of the foregoing problem, the present invention provides a pneumatic tire that improves the appearance of the side wall portion even when the gauge thickness of the side wall portion is thinned down.
A pneumatic tire (pneumatic tire 1) according to the present invention comprising: a tread portion (tread portion 2) is in contact with a road surface; and a side wall portion (side wall portion 3) is continuous to the tread portion and positioned inside a tire radial direction of the tread portion. A large region (large region 10) comprising a plurality of small regions (small regions 11, 12 and 13) having different arithmetic average roughness outside in a tire width direction is formed on outer surface of the side wall portion. A plurality of large regions 10 are formed along a tire circumferential direction and the tire radial direction. In a boundary line of adjacent large region 10, small regions having different arithmetic average roughness come into contact with each other.
According to the present invention, even when the gauge thickness of the side wall portion is thinned down, the appearance of the side wall portion is improved.
Hereinafter, an embodiment of the present invention will be described with reference to the drawings. In the illustration of the drawings, the same constituents are denoted by the same reference signs, and description thereof is omitted.
(1) Overall Schematic Configuration of a Pneumatic Tire
As shown in
The tread portion 2 is in contact with a road surface (unillustrated). In the tread portion 2, a pattern (unillustrated) corresponding to usage environment of the pneumatic tire 1 or the kind of a vehicle to be mounted is formed.
The side wall portion 3 is continuous to the tread portion 2 and positioned inside the tire radial direction of the tread portion 2. The side wall portion 3 is a region from the tire width direction outside end of the tread portion 2 to the upper end of the bead portion 7.
The carcass 6 forms a skeleton of the pneumatic tire 1. The carcass 6 has a radial structure having carcass cords (unillustrated) radially arranged along the tire radial direction. However, the carcass 6 is not limited to the radial structure, and may be a bias structure in which the carcass cords are arranged so as to cross each other in the tire radial direction.
The bead portion 7 is continuous to the side wall portion 3 and positioned inside the tire radial direction of the side wall portion 3. The bead portion 7 is annular, and the carcass 6 is folded back from the inside in the tire width direction to the outside in the tire width direction through the bead portion 7.
As shown in
Next, with reference to
Next, with reference to
In the small regions 11, 12 and 13, an arithmetic average roughness outside in the tire width direction is different from each other as shown in
In the example shown in
Further, as shown in
(Working and Effects)
As described above, the large region 10 comprising the plurality of small regions 11, 12 and 13 having different arithmetic average roughness outside in the tire width direction is formed on the outer surface of the side wall portion 3. The plurality of large regions 10 are formed along the tire circumferential direction and the tire radial direction. In the boundary lines of adjacent large region 10, small regions having different arithmetic average roughness come into contact with each other. The contrast caused by the difference in the arithmetic average roughness of the small regions 11, 12 and 13 produces a three-dimensional feeling with unevenness. Thus, even when the gauge thickness of the side wall portion 3 is thinned down, the appearance of the side wall portion 3 is improved.
As shown in
While the present invention has been described above by reference to the embodiment, it should be understood that the present invention is not intended to be limited to the descriptions and the drawings composing part of this disclosure. Various alternative embodiments, examples, and technical applications will be apparent to those skilled in the art according to this disclosure.
For example, as shown in
The shape of the large region 10 is not limited to quadrangular shown in
This application is based upon and claims the benefit of priority from Japanese Patent Application No. 2018-236003, filed on Dec. 18, 2018, the entire contents of which are incorporated herein by reference.
Number | Date | Country | Kind |
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2018-236003 | Dec 2018 | JP | national |
Filing Document | Filing Date | Country | Kind |
---|---|---|---|
PCT/JP2019/046889 | 11/29/2019 | WO |
Publishing Document | Publishing Date | Country | Kind |
---|---|---|---|
WO2020/129579 | 6/25/2020 | WO | A |
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