Pneumatic tire

Abstract

To provide a pneumatic tire having an excellent visual effect.SOLUTION: A pneumatic tire 1 has patterns 30 provided on a surface of a side wall 10. In the pneumatic tire 1, the pattern 30 has a plurality of annular diagrams 31 which are longer in a tire circumferential direction CD than a tire radial direction RD. The plurality of annular diagrams 31 are different in size from one another, and large annular diagrams 31 are located outside small annular diagrams 31 at intervals so as to form a proximity part 32 on one side in the tire circumferential direction CD of the smallest annular diagram 31a, the proximity part having an interval of the annular diagrams 31 being narrower than the other side.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] Although various forms of patterns have been proposed so far, there is a demand for an epoch-making pattern that produces a visual effect never seen before.

[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. The pattern has a plurality of annular figures that are longer in the tire circumferential direction than in the tire radial direction. The plurality of annular figures have different sizes from each other, and a large annular figure is arranged at an interval outside the small annular figure so as to form a proximity portion where the interval between the annular figures is narrower on one side in the tire circumferential direction of the smallest annular figure than on the other side.

Advantages of the Invention

[0008] In the present invention described above, by having the above characteristics, it is possible to suppress bleeding and produce a visual effect with a sense of depth.

Brief Description of the Drawings

[0009]

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Mode 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 the same structure as 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 bridged 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] In addition, one or more belts 4 are provided on the outer side in the tire radial direction of the carcass ply 2, and a belt reinforcing layer 5 is provided on the outer side in the tire radial direction 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 fibers with rubber. A tread rubber 6 is provided on the outer side in the tire radial direction of the belt reinforcing layer 5. A large number of grooves are provided in the tread rubber 6 to form a tread pattern.

[0015] In addition, sidewall rubbers 7 are provided on both sides in the tire axial direction of the carcass ply 2. The tread rubber 6 and the sidewall rubber 7 overlap in the buttless, but 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 also the entire visible range when the pneumatic tire 1 is viewed from the tire axial direction is defined as the sidewall 10.

[0016] In addition, a sheet-like inner liner 8 made of 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 area 11 is an annular area centered on the tire rotation axis. The decorative area 11 is an area with a constant width sandwiched between the small-diameter circular inner diameter side line 12 and the large-diameter circular outer diameter side line 13. The inner diameter side line 12 and the outer diameter side line 13 may be lines formed on the tire surface by concave, convex or steps, or may be virtual lines that do not actually exist. The width HA in the tire diameter direction RD of the decorative area 11 is 5% or more and 60% or less (preferably 10% or more and 35% or less) of the tire cross-sectional height H (the length in the tire diameter direction RD from the inner diameter end of the bead core to the outer diameter surface of the inflated tire 1).

[0019] The location of the decorative area 11 in the tire diameter direction RD is a location including the position of the maximum width of the inflated tire 1. Here, the position of the maximum width of the inflated tire 1 means 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] In addition, the decorative area 11 may be provided on the sidewall 10 so as to include a location where steps are likely to appear on the surface of the sidewall 10. The location where steps are likely to appear on the surface of the sidewall 10 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 end of the folded-back portion 2a of the carcass ply 2 overlaps in the tire width direction.

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

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

[0023] One or more logos 16 are formed side by side in the tire circumferential direction CD in the logo area 11a. The logo 16 consists of characters, numbers, symbols, figures, etc., and displays various information such as the tire manufacturer, brand, variety, size, etc. These logos 16 that make up the logo 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] All of the plurality of annular figures 31 that make up the pattern 30 are annular figures that are longer in the tire circumferential direction CD than in the tire radial direction RD. In the present embodiment, the plurality of annular figures 31 are substantially elliptical.

[0026] In the plurality of annular figures 31, the ratio of the length in the tire radial direction RD to the length in the tire circumferential direction CD is preferably 0.5 or more and 0.8 or less. Also, the length in the tire radial direction RD of the largest annular figure 31 among the plurality of annular figures 31 is preferably 50% or more and 95% or less of the width HA in the tire radial direction RD of the decoration area 11.

[0027] The plurality of annular figures 31 that constitute the pattern 30 are arranged such that a large annular figure 31 surrounds an inner annular figure 31 with a space therebetween outside the small annular figure 31. The plurality of annular figures 31 are arranged so as to form a proximity portion 32 on one side in the tire circumferential direction CD of the smallest annular figure 31a and a separated portion 33 on the other side.

[0028] The interval K1 in the tire circumferential direction CD between adjacent annular figures 31 in the proximity portion 32 is narrower than the interval K2 in the tire circumferential direction CD of the annular figures 31 in the separated portion 33 (see FIG. 3). That is, in the annular figures 31, on one side rather than the other side in the tire width direction of the smallest annular figure 31, the intervals in the tire circumferential direction CD of the annular figures 31 are narrow and the annular figures 31 are arranged densely. The interval K2 in the separated portion 33 between adjacent annular figures 31 is preferably 1.1 times or more and 5.0 times or less the interval K1 in the proximity portion 32. The interval K1 of the annular figures 31 in the proximity portion 32 and the interval K2 of the annular figures 31 in the separated portion 33 may gradually increase from the inside to the outside, or may be at equal intervals.

[0029] Here, the interval in the tire circumferential direction CD between adjacent annular figures 31 is the distance from the center P to the position on the annular figure 31 that is farthest from the tire circumferential direction CD. When the annular figure 31 is elliptical, it is the distance between points on the major axis.

[0030] In such a plurality of annular figures 31, as shown in FIG. 3, the center Pa of the smallest annular figure 31a is arranged at a position closer to one side in the tire circumferential direction CD than the center Pb of the largest annular figure 31b, and the center Pc of the other annular figures 31 is arranged between the center Pa of the smallest annular figure 31a and the center Pb of the largest annular figure 31b. The centers Pa, Pb, Pc of the annular figures 31 (hereinafter, these may also be collectively referred to as the center P) are preferably provided on one reference line 21. The center P of the annular figure 31 shall coincide with the centroid of the surface formed by the annular figure 31. However, when the shape formed by the annular figure 31 is a shape whose center is defined mathematically, the center P of the annular figure 31 shall be determined according to that definition.

[0031] Further, for the plurality of annular figures 31, when comparing the interval K3 on the outer side in the tire radial direction RD from the center P with respect to adjacent annular figures 31 and the interval K4 on the inner side in the tire radial direction RD, the interval K3 and the interval K4 may be equal or different. When both intervals are different, it is preferable that the interval K3 on the outer side in the tire radial direction RD is larger than the interval K4 on the inner side in the tire radial direction RD. Note that the above intervals K3 and K4 are the distances between points on a straight line m parallel to the tire radial direction RD passing through the center Pa of the smallest annular figure 31.

[0032] Further, as shown in FIG. 2, for the plurality of patterns 30 provided in the pattern area 11b, it is preferable that the centers P of the plurality of annular figures 31b constituting each pattern 30 are provided on one reference line 21. The reference line 21 is a line extending in the tire circumferential direction at a specific position in the tire radial direction in the decoration area 11. This reference line 21 is not actually drawn in the decoration area 11 but is a virtual line. The position of the reference line 21 in the tire radial direction is preferably the center position in the tire radial direction in the decoration area 11. Further, the reference line 21 is preferably a line that draws a circle with a radius of 45% or more and 65% or less of the tire cross-sectional height H centered on the tire rotation axis.

[0033] Each of the plurality of annular figures 31 is formed by connecting convex ridges, which are called concave grooves that are recessed with respect to the surface of the side wall or ridges that protrude with respect to the surface of the side wall, in a circular shape. When the annular figure 31 is formed from the convex ridge 20, as the cross-sectional shape in the direction orthogonal to the longitudinal direction of the convex ridge 20, there are 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 obtained by deforming the triangle in FIG. 6 so as to be inclined. 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).

[0034] In the convex ridge 20 having any of the cross-sectional shapes in FIGS. 4 to 9, the height H1 of the convex ridge 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 the convex ridge 20 having any cross-sectional shape, the width W1 of the convex ridge 20 is 0.1 mm or more and 1.0 mm or less. The convex ridge 20 can be formed by a mold used during vulcanization molding. The convex ridge 20 can be formed by various processes such as machining and laser processing. For a small convex ridge 20 having 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 in which fine irregularities are formed by laser processing.

[0035] Also, assuming that the radius of the semi-circle in FIGS. 4 and 5 is R, the length H2 of the straight line of the convex ridge 20 having the cross-sectional shape shown in FIG. 5, which is composed of a semi-circle and a straight line, is (the height H1 of the convex ridge 20) - (the radius R of the semi-circle). Also, in the convex ridge 20 having 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 (that is, the width W1 of the convex ridge 20).

[0036] 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.

[0037] The strip-shaped region 40 is an annular region provided adjacent to the outer circumference of the decorative region 11. A plurality of ridges 41 protruding from the outer surface of the sidewall 10 are provided in the strip-shaped region 40. In one embodiment, the plurality of ridges 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.

[0038] By providing such a strip-shaped region 40, it is possible to suppress the interface unevenness and bare parts between the tread rubber 6 and the sidewall 10 members. Further, a black strip-shaped region 40 is formed by the light attenuation effect due to the provision of the ridges 41, and the decorative region 11 can be made prominent.

[0039] Such a strip-shaped region 40, like the decorative region 11, is provided on the sidewall 10 so as to include places where the interface between the tread rubber 6 and the sidewall rubber 7 appears on the tire surface, places where the end of the folded-back portion 2a of the carcass ply 2 overlaps in the tire width direction, places where the end of the belt 4 overlaps in the tire width direction, etc., places where steps are likely to appear on the surface of the sidewall 10. 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.

[0040] In the pneumatic tire 1 of the present embodiment, a pattern 30 in which a large annular figure 31 is arranged outside a small annular figure 31 is provided on the sidewall 10 so as to form a proximity portion 32 where the interval of the annular figure 31 is narrower than a separation portion 33 provided on the other side of one side in the tire circumferential direction CD of the smallest annular figure 31a. Therefore, compared with the case where the annular figures 31 are arranged at equal intervals on both sides in the tire circumferential direction CD of the smallest annular figure 31a, while suppressing bleeding, a contrast (light and dark) with a sense of depth is generated from the separation portion 33 toward the proximity portion 32, exhibiting a novel visual effect.

[0041] Further, since the annular figures 31 are provided at intervals in the proximity portion 32, the annular figures 31 do not come too close to each other, and it becomes easy to mold the proximity portion 32 into a desired uneven shape when vulcanizing and molding the tire.

[0042] Further, when a plurality of annular figures 31 are arranged at equal intervals in the proximity portion 32 and the separation portion 33, a smoother sense of depth is generated in the pattern 30. Further, by providing a plurality of annular figures 31 so that the interval of the annular figures 31 gradually widens at a constant ratio from the innermost annular figure 31 to the outermost one, the sense of depth generated from the separation portion 33 toward the proximity portion 32 can be emphasized.

[0043] Further, when the pneumatic tire 1 is a tire with a specified rotation direction, all the patterns 30 provided on the surface of the sidewall 10 may be arranged so that the proximity portion 32 is located on the front side in the rotation direction RF (see FIG. 2). By arranging the pattern 30 in this way, the rotation direction can be indicated while having excellent design properties.

[0044] (Modification example) The above embodiment is presented as an example and is 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.

[0045] For example, the shapes of the plurality of annular figures 31 are not limited to the substantially elliptical shape of the above 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 embodiment, an oblong shape, a perfect circle shape, an egg shape, and the like. The oval also includes a closed curve formed by the intersection of the surface of a cone and a plane that completely crosses the cone.

[0046] Further, in the above embodiment, all the patterns 30 are provided on the surface of the sidewall 10 such that the proximity portion 32 is located on one side in the tire circumferential direction CD. However, various arrangements are possible for the arrangement of the proximity portion 32.

[0047] For example, as shown in FIG. 10, the pattern 30 may be arranged such that the proximity portion 32 faces one of the logo regions 11a (the left logo region 11a in FIG. 10), or as shown in FIG. 11, the pattern 30 may be arranged such that the proximity portion 32 faces the logo region 11a to which it is close. Further, as shown in FIGS. 12 and 13, the pattern 30 may be arranged such that the direction of the proximity portion 32 alternates in the tire circumferential direction CD. As shown in FIGS. 10, 11, and 12, when a pair of patterns 30 adjacent to the logo region 11a in the tire circumferential direction CD are arranged with the proximity portion 32 facing the logo region 11a, the line of sight of the consumer is likely to be directed to the logo region 11a sandwiched by the proximity portion 32, and the logo 16 provided in the logo region 11a can be emphasized.

[0048] Further, as a result of a large number of annular figures 31 being provided in one pattern 30, some of the large annular figures 31 may be interrupted without fitting within the decoration region 11 as shown in FIG. 14. In such a case, it is preferable to provide a large number of annular figures 31 such that five or more annular figures 31 that are annularly connected without interruption fit within the decoration region 11.

[0049] In addition, 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.

[0050] In addition, in the above-described embodiment, four patterns 30 are provided in one pattern region 11b, but any number of patterns 30 may be provided in one pattern region 11b.

[0051] Note that each of the above dimensions in this specification is in the normal state of no load with an inflated tire mounted on a normal rim and filled with a 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.

[0052] Note that the various numerical ranges described in the specification can be arbitrarily combined with their upper 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.

Explanation of Reference Numerals

[0053] 1... inflated tire, 4... belt, 6... tread rubber, 7... sidewall rubber, 9... bead, 10... sidewall, 11... decorative region, 11a... emblem region, 11b... pattern region, 12... inner diameter side line, 13... outer diameter side line, 16... emblem, reference line... 21, 30... pattern, 31... annular figure, P... center

Claims

1. In a pneumatic tire having a pattern provided on the surface of a sidewall, the pattern has a plurality of annular figures that are longer in the tire circumferential direction than in the tire radial direction, the plurality of annular figures have different sizes from each other, and the large annular figure is arranged so as to surround the small inner annular figure with a space therebetween outside the small annular figure so as to form a proximity portion where the interval between the annular figures is narrower on one side in the tire circumferential direction of the smallest annular figure than on the other side. A pneumatic tire.

2. The pneumatic tire according to claim 1, wherein the interval between the plurality of annular figures changes in the proximity portion.

3. The pneumatic tire according to claim 1 or 2, wherein the annular figure is an oval figure.

4. The pneumatic tire according to any one of claims 1 to 3, wherein the ratio of the length in the tire radial direction to the length in the tire circumferential direction of the annular figure is 0.5 or more and 0.8 or less.

5. The plurality of annular figures are formed by concave grooves that are recessed with respect to the surface of the sidewall or ridges that protrude 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 a triangle, a trapezoid, or a semicircle.

6. The surface of the sidewall is provided with a logo area provided with one or more logos and a pair of the patterns, The pneumatic tire according to any one of claims 1 to 5, wherein the pair of patterns are arranged on both sides in the tire circumferential direction of the logo area with the proximity portion facing the logo area.

7. The pneumatic tire is a tire with a designated rotation direction, The pneumatic tire according to any one of claims 1 to 5, wherein the pattern is provided on the surface of the sidewall such that the proximity portion is located on the front side in the rotation direction.

8. The pneumatic tire according to any one of claims 1 to 7, wherein the adjacent annular figures have a larger interval in the outer tire diameter direction than in the inner tire diameter direction.

9. In the sidewall, in a region where a plurality of ridges extending in the tire diameter direction are arranged at equal intervals in the tire circumferential direction, outside the decorative region where the annular figure is provided in the tire diameter direction, a region having a dimension in the tire diameter direction of 5 mm or more and 12 mm or less is provided. The pneumatic tire according to any one of claims 1 to 8.

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