Pneumatic tire

Abstract

To provide a pneumatic tire with superior visual effects.SOLUTION: A pneumatic tire 1 is provided with patterns 30 on a surface of each of side walls 10. In the pneumatic tire 1, the pattern 30 includes a plurality of annular figures 31 in which the lengths of a first axis L1 are equal, whereas their lengths of a second axis L2 orthogonal to the first axis L1 differ from each other. The plurality of annular figures 31 are aligned such that their second axes L2 coincide mutually, and such that the annular patterns 31 gradually increase in size from the smallest annular pattern 31a toward one side 21 of the second axis L2.SELECTED DRAWING: Figure 2

Description

Technical Field

[0001] The present invention relates to pneumatic tires.

Background Art

[0002] There is known a pneumatic tire provided with a pattern formed by arranging a plurality of ridges extending along the tire surface on the surface of the sidewall.

[0003] Many of the conventional patterns provided on the surface of the sidewall are those in which a large number of linearly extending ridges are arranged at equal intervals. Also, as disclosed in Patent Document 1, those in which curved ridges are arranged at equal intervals are also known. Any of these patterns enhances the designability of the sidewall.

Prior Art Documents

Patent Documents

[0004]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0005] Various forms of patterns have been proposed so far, but there is a demand for an epoch - making pattern that produces a never - before - seen visual effect.

[0006] Therefore, an object of the present invention is to provide a pneumatic tire that produces a visual effect.

Means for Solving the Problems

[0007] The pneumatic tire of the present embodiment is a pneumatic tire having a pattern provided on the surface of the sidewall, wherein the pattern has a plurality of annular figures with equal lengths of a first axis and different lengths of a second axis orthogonal to the first axis, and the plurality of annular figures are arranged with the second axis coinciding with each other and gradually increasing in size from the smallest annular figure to one side of the second axis.

Advantages of the Invention

[0008] In the present invention described above, by having the above characteristics, a three-dimensional and characteristic visual effect can be produced.

Brief Description of the Drawings

[0009]

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Embodiments for Carrying Out the Invention

[0010] Hereinafter, an embodiment of the present invention will be described with reference to the drawings.

[0011] The pneumatic tire 1 of the embodiment has a structure similar to that of a general radial tire except for the structure of the sidewall. The cross-sectional structure of the pneumatic tire 1 of the embodiment is shown in FIG. 1. Note that only half in the tire axial direction is shown in FIG. 1, and the actual pneumatic tire 1 is substantially symmetric about the center line C.

[0012] In the pneumatic tire 1, beads 9 are provided on both sides in the tire axial direction. The bead 9 is composed of a bead core made of a steel wire wound in a circular shape and a rubber bead filler provided on the radially outer side of the bead core.

[0013] One or two carcass plies 2 are stretched over the beads 9 on both sides in the tire axial direction. The carcass ply 2 is a sheet-like member in which a large number of ply cords arranged in a direction orthogonal to the tire circumferential direction are covered with rubber. The carcass ply 2 forms the skeletal shape of the pneumatic tire 1 between the beads 9 on both sides in the tire axial direction, and wraps the bead 9 by being folded back and wound up from the inner side to the outer side in the tire axial direction around the bead 9. Further, a rubber chafer 3 is provided at a location on the radially outer side in the tire axial direction of the folded-back portion 2a of the carcass ply 2.

[0014] Also, one or a plurality of belts 4 are provided on the radially outer side of the carcass ply 2, and a belt reinforcing layer 5 is provided on the radially outer side of the belt 4. The belt 4 is a member formed by covering a large number of steel cords with rubber. The belt reinforcing layer 5 is a member formed by covering a large number of cords made of organic fiber with rubber. A tread rubber 6 is provided on the radially outer side of the belt reinforcing layer 5. A large number of grooves are provided in the tread rubber 6 to form a tread pattern.

[0015] On both sides of the carcass ply 2 in the tire axial direction, sidewall rubbers 7 are provided. The tread rubber 6 and the sidewall rubber 7 overlap in a tubeless tire, and either the tread rubber 6 or the sidewall rubber 7 may overlap on the tire surface side. The portion of the sidewall rubber 7 on the inner side in the tire radial direction extends close to the bead 9 and covers a part of the rubber chafer 3. In the present embodiment, not only the portion where the sidewall rubber 7 appears on the tire surface, but the entire visible range when the pneumatic tire 1 is viewed from the tire axial direction is defined as the sidewall 10.

[0016] Also, an inner liner 8 made of a sheet-like rubber with low air permeability is attached to the inside of the carcass ply 2. In addition to these members, members such as a belt under pad and a chafer are provided as required for the functions of the tire.

[0017] As shown in FIGS. 1 and 2, a decorative region 11 and a strip region 40 are provided on at least one of the sidewalls 10 on both sides in the tire axial direction.

[0018] The decorative region 11 is an annular region centered on the tire rotation axis. The decorative region 11 is a region with a constant width sandwiched between an inner diameter side line 12 of a small-diameter circle and an outer diameter side line 13 of a large-diameter circle. The inner diameter side line 12 and the outer diameter side line 13 may be lines formed by concave, convex, or steps on the tire surface, or may be virtual lines that do not actually exist. The width HA of the decorative region 11 in the tire radial direction RD is 5% or more and 60% or less (preferably 10% or more and 35% or less) of the tire section height H (the length in the tire radial direction RD from the inner diameter end of the bead core to the outer diameter surface of the pneumatic tire 1).

[0019] The location of the decorative region 11 in the tire radial direction RD is a location including the position of the maximum width of the pneumatic tire 1. Here, the position of the maximum width of the pneumatic tire 1 is the position where the length in the tire axial direction from the surface of one sidewall 10 in the tire axial direction to the surface of the other sidewall 10 in the tire axial direction is the longest.

[0020] Note that the decorative area 11 may be provided on the sidewall 10 so as to include a location on the surface of the sidewall 10 where a step is likely to appear. A location on the surface of the sidewall 10 where a step is likely to appear is typically a location at the end of a tire component, such as a location where the interface between the tread rubber 6 and the sidewall rubber 7 appears on the tire surface, or a location where the tip of the folded-back portion 2a of the carcass ply 2 overlaps in the tire width direction.

[0021] As shown in FIG. 2, emblem areas 11a in which emblems 16 are formed are provided at two opposing locations of the annular decorative area 11. Also, pattern areas 11b in which patterns 30 are formed are provided at two opposing locations of the annular decorative area 11 so as to be sandwiched between the two emblem areas 11a.

[0022] In order to sufficiently space between adjacent emblem areas 11a and pattern areas 11b, the minimum value of the distance LB (the length in the tire circumferential direction CD from the emblem 16 provided in the emblem area 11a to the end of the pattern 30 provided in the pattern area 11b) between the end of the emblem area 11a and the end of the pattern area 11b is set to 3 mm. Also, in order to sufficiently secure the area of the pattern 30 provided in the decorative area 11, the maximum value of the distance LB between the emblem area 11a and the pattern area 11b is set to 60% of the length LA in the tire circumferential direction CD of the emblem area 11a (the distance between the emblems 16 provided at both ends in the tire circumferential direction of the emblem area 11a).

[0023] One or more emblems 16 are formed side by side in the tire circumferential direction CD in the emblem area 11a. The emblems 16 are composed of letters, numbers, symbols, figures, etc., and display various information such as the tire manufacturer, brand, type, size, etc. These emblems 16 constituting the emblem area 11a are formed by being bordered by concave or convex lines.

[0024] A plurality of patterns 30 are formed side by side in the tire circumferential direction CD in the pattern area 11b. As shown in FIGS. 2 and 3, the pattern 30 is configured by combining a plurality of annular figures 31 having different sizes from each other. Preferably, the pattern 30 is configured by combining five or more annular figures 31.

[0025] As shown in FIG. 3, the plurality of annular figures 31 constituting the pattern 30 are annular figures having the same length of the first axis L1 and different lengths of the second axis L2 orthogonal to the first axis L1. The plurality of annular figures 31 are arranged such that the second axis L2 coincides with each other, and are arranged in order from the smallest annular figure 31a so that the annular figure 31 gradually increases toward one side L2a of the second axis L2.

[0026] Thereby, a separation portion 33 is formed on one side L2a of the second axis L2 of the pattern 30, in which the plurality of annular figures 31 are arranged at intervals. The plurality of annular figures 31 may be provided so as to be arranged at equal intervals in the separation portion 33, or may be provided so that the interval between the annular figures 31 gradually widens toward one side L2a of the second axis L2 in the separation portion 33.

[0027] The plurality of annular figures 31 may be arranged such that the first axis L1 faces the tire radial direction RD and the second axis L2 faces the tire circumferential direction CD. The plurality of annular figures 31 may be elliptical, and the first axis L1 may be one of the major axis and the minor axis of the ellipse, and the second axis L2 may be the other of the major axis and the minor axis.

[0028] In the plurality of annular figures 31, the ratio of the length of the second axis L2 to the length of the first axis L1 is preferably 0.5 or more and 2.0 or less. That is, the length of the second axis L2 of the smallest annular figure 31a is preferably 0.5 times or more the length L1 of the first axis L1, and the length of the second axis L2 of the largest annular figure 31b is preferably 2.0 times or less the length of the first axis L1.

[0029] The length in the tire radial direction RD of the largest annular figure 31b among the plurality of annular figures 31 (in this embodiment, the length of the first axis L1) is preferably 50% or more and 95% or less of the width HA in the tire radial direction RD of the decoration area 11.

[0030] The plurality of annular figures 31 may be arranged to form overlapping portions 32 that overlap each other on the other side L2b of the second axis L2 as shown in FIG. 3, or may be arranged to form adjacent portions 36 that are spaced apart on the other side L2b of the second axis L2 as shown in FIG. 13.

[0031] When forming the adjacent portions 36, the interval K1 in the direction of the second axis L2 of the annular figures 31 in the adjacent portions 36 is narrower than the interval K2 in the direction of the second axis L2 of the annular figures 31 in the separated portions 33. Also, when forming the adjacent portions 36, the plurality of annular figures 31 may be provided so as to be arranged at equal intervals in the adjacent portions 36, or may be provided so that the interval gradually widens toward one side L2a of the second axis L2 in the adjacent portions 36. The interval K1 in the direction of the second axis L2 of the annular figures 31 in the adjacent portions 36 is preferably 0.4 times or more and 0.6 times or less of the interval K2 in the direction of the second axis L2 of the annular figures 31 in the separated portions 33.

[0032] All of the plurality of annular figures 31 are formed by connecting annularly convex ridges called concave grooves that sink into the surface of the side wall or ridges that protrude from the surface of the side wall. When the annular figure 31 is formed from the convex ridge 20, the cross-sectional shape in the direction orthogonal to the longitudinal direction of the convex ridge 20 includes a semi-circle as shown in FIG. 4, a shape composed of a semi-circle and a straight line below it as shown in FIG. 5, a triangle as shown in FIG. 6, a shape in which the apex of the triangle as shown in FIG. 7 is rounded, a trapezoid as shown in FIG. 8, a rectangle as shown in FIG. 9, and the like. Here, the shape in which the apex of the triangle as shown in FIG. 7 is rounded is a kind of triangle. Also, although not shown, there may be shapes in which these cross-sectional shapes are slightly deformed, for example, a sawtooth shape in which the triangle in FIG. 6 is deformed by tilting it. Note that the lines depicted as the annular figure 31 in FIGS. 2 and 3 are the center lines in the width direction of the convex ridge 20 (the lines at the positions indicated by T in FIGS. 4 to 9).

[0033] In any of the ribbed strips 20 with the cross-sectional shapes shown in FIGS. 4 to 9, the height H1 of the ribbed strip 20 is 0.1 mm or more and 0.8 mm or less (preferably 0.1 mm or more and 0.4 mm or less). Also, in any of the ribbed strips 20 with the cross-sectional shapes, the width W1 of the ribbed strip 20 is 0.1 mm or more and 1.0 mm or less. The ribbed strip 20 can be formed by a mold used during vulcanization molding. The ribbed strip 20 can be formed by various processes such as machining or laser processing. For a small ribbed strip 20 with a height H1 of about 0.1 mm to 0.2 mm and a width W1 of about 0.1 mm to 0.2 mm, it can be formed by a mold with fine irregularities formed by laser processing.

[0034] Also, if the radius of the semi-circle in FIGS. 4 and 5 is R, the length H2 of the straight line of the ribbed strip 20 with the cross-sectional shape shown in FIG. 5, which consists of a semi-circle and a straight line, is (the height H1 of the ribbed strip 20) - (the radius R of the semi-circle). Also, in the ribbed strip 20 with a trapezoidal cross-section as shown in FIG. 8, the length W2 of the upper base is 20% or more and 50% or less of the length of the lower base (i.e., the width W1 of the ribbed strip 20).

[0035] In the present embodiment, as shown in FIG. 2, a plurality of patterns 30 are provided in the decorative region 11 at intervals in the tire circumferential direction CD. It is preferable that the plurality of patterns 30 are arranged such that other patterns 30 are located at positions facing each other across the tire rotation axis.

[0036] The strip-shaped region 40 is an annular region provided adjacent to the outer circumference of the decorative region 11. A plurality of ribbed strips 41 rising from the outer surface of the sidewall 10 are provided in the strip-shaped region 40. In one embodiment, the plurality of ribbed strips 41 are arranged at equal intervals with an interval of 0.3 to 1.0 mm in the tire circumferential direction CD. The strip-shaped region 40 may be provided in a part of the tire circumferential direction CD, but in this example, it is provided over the entire circumference of the tire circumferential direction CD. Therefore, the strip-shaped region 40 is formed in an annular shape adjacent to the outside of the decorative region 11 and surrounding it over the entire circumference. The dimension HC (see FIG. 1) of the strip-shaped region 40 in the tire radial direction RD is preferably 5 mm to 12 mm.

[0037] By providing such a strip-shaped region 40, it is possible to suppress the interface unevenness and bare areas between the tread rubber 6 and the members of the sidewall 10. In addition, due to the light attenuation effect caused by the provision of the ribs 41, a black strip-shaped region 40 is formed, and the decorative region 11 can be made prominent.

[0038] Such a strip-shaped region 40 may be provided on the sidewall 10 so as to include locations where the interface between the tread rubber 6 and the sidewall rubber 7 appears on the tire surface, locations where the end portion of the folded-back portion 2a of the carcass ply 2 overlaps with the tire width direction, locations where the end portion of the belt 4 overlaps with the tire width direction, etc., that is, locations where steps are likely to appear on the surface of the sidewall 10, such as the end portions of the tire constituent members. A parting line 42, which is a dividing line between the tread mold and the sidewall mold in the tire mold, may be formed at the radially outer boundary portion of the strip-shaped region 40.

[0039] In the pneumatic tire 1 of the present embodiment, the pattern 30 provided on the sidewall 10 is configured by arranging a plurality of annular figures 31 such that the second axis L2 coincides with each other, and the annular figures 31 gradually increase in size from the smallest annular figure 31a to one side L2a of the second axis L2. Therefore, the pattern 30 exhibits a characteristic visual effect with a three-dimensional sense like a bent bellows.

[0040] In addition, when an overlapping portion 32 is provided on the other side L2b of the second axis L2 of the pattern 30 by arranging a plurality of annular figures 31 to overlap each other, the three-dimensional sense of the pattern 30 can be emphasized.

[0041] In addition, when a proximity portion 36 is provided on the other side L2b of the second axis L2 of the pattern 30 by arranging a plurality of annular figures 31 at intervals, the numerous annular figures 31 do not approach too closely, and it becomes easy to mold the proximity portion 36 into a desired uneven shape by vulcanizing and molding the tire.

[0042] (Modified Example) The above-described embodiments are presented as examples and are not intended to limit the scope of the invention. This novel embodiment can be implemented in various other forms, and various omissions, replacements, and changes can be made without departing from the gist of the invention.

[0043] For example, the shapes of the plurality of annular figures 31 are not limited to the substantially elliptical shape of the above-described embodiment. When viewed from a direction perpendicular to the surface of the sidewall 10, an annular figure that is longer in the tire circumferential direction CD than in the tire radial direction RD may be used. Among such annular figures, a preferable shape is a shape called an oval. An oval is a closed annular shape mainly composed of curves (for example, more than half of the total length of the line forming the contour of the annular figure 31 is a curve). The oval includes, in addition to the elliptical shape of the above-described embodiment, an oblong shape, a perfect circular shape, an egg shape, etc. Also, the oval includes a closed curve formed by the intersection of the surface of a cone and a plane that completely traverses the cone.

[0044] Also, in the above-described embodiment, all the patterns 30 are provided on the surface of the sidewall 10 such that the separated portion 33 is located on one side in the tire circumferential direction CD, but various arrangements are possible for the arrangement of the separated portion 33.

[0045] For example, as shown in FIG. 10, the pattern 30 may be arranged such that the separated portion 33 faces one of the emblem regions 11a (the left emblem region 11a in FIG. 10), or as shown in FIG. 11, the pattern 30 may be arranged such that the separated portion 33 faces the adjacent emblem region 11a. Also, as shown in FIG. 12, the pattern 30 may be arranged such that the overlapping portion 32 faces the opposite of the adjacent emblem region 11a.

[0046] Also, in the above-described embodiment, two pattern regions 11b are provided for one sidewall 10, but one or three or more pattern regions 11b may be provided for one sidewall 10.

[0047] In the above embodiment, four patterns 30 are provided in one pattern area 11b, but any number of patterns 30 may be provided in one pattern area 11b.

[0048] In addition, each of the above dimensions in this specification is in the normal state without load when the pneumatic tire is mounted on a normal rim and filled with the normal internal pressure. The normal rim is the "standard rim" in the JATMA standard, the "Measuring Rim" in the TRA standard and the ETRTO standard. The normal internal pressure is the "maximum air pressure" in the JATMA standard, the "maximum value" described in "TIRE LOAD LIMITS AT VARIOUS COLD INFLATION PRESSURES" in the TRA standard, or the "INFLATION PRESSURE" in the ETRTO standard. However, in the case of a passenger car tire, it is usually 180 kPa, but in the case of a tire marked with Extra Load or Reinforced, it is 220 kPa.

[0049] Note that the various numerical ranges described in the specification can be arbitrarily combined with their upper limit values and lower limit values, and all of these combinations are described in the specification as preferred numerical ranges. Also, the description of the numerical range "X to Y" means X or more and Y or less.

Description of Reference Numerals

[0050] 1... pneumatic tire, 4... belt, 6... tread rubber, 7... sidewall rubber, 9... bead, 10... sidewall, 11... decorative area, 11a... emblem area, 11b... pattern area, 12... inner diameter side line, 13... outer diameter side line, 16... emblem, 30... pattern, 31... circular figure, 32... overlapping part, 33... separated part, 36... adjacent part, L1... first axis, L2... second axis

Claims

1. In a pneumatic tire having a pattern provided on the surface of a sidewall, the pattern has a plurality of five or more annular figures with equal lengths of a first axis facing the tire radial direction and different lengths of a second axis facing the tire circumferential direction orthogonal to the first axis, the plurality of annular figures are figures formed by connecting annularly concave grooves recessed with respect to the surface of the sidewall or ridges protruding with respect to the surface of the sidewall, with the second axes thereof being made to coincide with each other, and are arranged so that the length along the direction of the second axis of the annular figure gradually increases from the smallest annular figure to one side of the second axis. A pneumatic tire.

2. The pneumatic tire according to claim 1, wherein a plurality of the annular figures overlap on the other side of the second axis.

3. A plurality of the annular figures are arranged with a gap on the other side of the second axis. The pneumatic tire according to claim 1, which overlaps.

4. The pneumatic tire according to any one of claims 1 to 3, wherein the ratio of the length of the second axis to the length of the first axis of the annular figure is 0.5 or more and 2.0 or less.

5. The plurality of annular figures are composed of concave grooves recessed with respect to the surface of the sidewall or ridges protruding with respect to the surface of the sidewall, The pneumatic tire according to any one of claims 1 to 4, wherein the cross-sectional shape of the plurality of annular figures is triangular, trapezoidal or semi-circular.

6. In the sidewall, a region where a plurality of ridges extending in the tire radial direction are arranged at equal intervals in the tire circumferential direction outside the decorative region where the annular figure is provided in the tire radial direction, and the dimension in the tire radial direction is 5 mm or more and 12 mm or less. The pneumatic tire according to any one of claims 1 to 5, provided with a region.

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