Pneumatic tire

Abstract

To provide a pneumatic tire in which visual effects are generated.SOLUTION: In a pneumatic tire of an embodiment, patterns are formed on each of side walls 10. The side wall 10 is configured with: a reference line 21 extending in a tire circumferential direction; and a plurality of reference points 22 provided on the reference line 21. The side wall is provided with annular protrusions 20 centered respectively on the reference points 22. Further, the plurality of protrusions 20 have the same shape and are mutually superposed to form the patterns.SELECTED DRAWING: Figure 2

Description

Technical Field

[0001] The present invention relates to pneumatic tires.

Background Art

[0002] For example, as described in Patent Document 1, pneumatic tires having patterns provided on the sidewalls are known. The patterns are formed by arranging a number of ridges side by side.

[0003] Many of the conventional patterns are those in which a 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] By the way, although beautiful patterns have been frequently proposed, epoch - making patterns that produce a never - before - seen visual effect have not been proposed very much.

[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 embodiment is a pneumatic tire having a pattern formed on the sidewall. On the sidewall, a reference line extending in the tire circumferential direction and a plurality of reference points provided on the reference line are set. An annular rib is provided centering on each of the reference points, and the plurality of ribs have the same shape and overlap each other to form the pattern. 、The shape of the annular pattern is oval It is characterized by this.

Effect of the Invention

[0008] By having the above characteristics, the pneumatic tire of the embodiment produces a visual effect with a sense of depth.

Brief Description of the Drawings

[0009]

Figure 1

Figure 2

Figure 3

Figure 4

Figure 5

Figure 6

Figure 7

Figure 8

Figure 9

Figure 10

Figure 11

Figure 12

Figure 13

Figure 14

Figure 15

Figure 16

Figure 17

Mode for Carrying Out the Invention

[0010] 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.

[0011] In the pneumatic tire 1, bead portions 9 are provided on both sides in the tire axial direction. The bead portion 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.

[0012] One or two carcass plies 2 are bridged over the bead portions 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 bead portions 9 on both sides in the tire axial direction, and wraps the bead portion 9 by being folded back and wound up from the inside to the outside in the tire axial direction around the bead portion 9. Further, a rubber chafer 3 is provided at a location on the radially outer side of the folded-back portion 2a of the carcass ply 2 in the tire axial direction.

[0013] Further, 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.

[0014] Further, 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 buttress, 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 near the bead portion 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.

[0015] Further, a sheet-like inner liner 8 made of a 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.

[0016] As shown in FIGS. 1 and 2, a decorative area 11 is provided on at least one of the sidewalls 10 on both sides in the tire axial direction. The decorative area 11 is in the form of an annulus centered on the tire rotation axis. The decorative area 11 is an area 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 stepped portions on the tire surface, or may be virtual lines that do not actually exist. The width HA in the tire radial direction of the decorative area 11 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 from the inner diameter end to the outer diameter surface of the pneumatic tire 1).

[0017] The position in the tire radial direction of the decorative region 11 is a position including the position of the maximum width of the pneumatic tire 1. Here, the position of the maximum width of the pneumatic 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.

[0018] Also, in FIG. 1, the decorative region 11 is provided in a form including a place where the interface between the tread rubber 6 and the sidewall rubber 7 appears on the tire surface. Thus, it is preferable that the decorative region 11 is provided in a form including a place where a step is likely to appear on the surface of the sidewall 10. The place where a step is likely to appear on the surface of the sidewall 10 is typically the end part of a tire component. As such a typical place, in addition to the place where the interface between the tread rubber 6 and the sidewall rubber 7 appears on the tire surface as described above, for example, there is the position in the tire axial direction of the turn-up end 2b of the carcass ply 2 (the end of the folded-back part 2a of the carcass ply 2).

[0019] As shown in FIG. 2, labelings 15 are provided at two opposing positions of the annular decorative region 11. Also, a pattern 14 is provided in the place sandwiched between the two labelings 15.

[0020] In order to sufficiently space between adjacent labelings 15 and the pattern 14, the minimum value of the interval LB (the length in the tire circumferential direction from the end of the labeling 15 to the end of the pattern 14) between the labeling 15 and the pattern 14 is set to 3 mm. Also, in order to sufficiently secure the area of the pattern 14, the maximum value of the interval LB between the labeling 15 and the pattern 14 is set to 60% of the length LA in the tire circumferential direction of the labeling 15 (the length from one end in the tire circumferential direction of the labeling 15 to the other end in the tire circumferential direction of the labeling 15).

[0021] The labeling 15 is formed by arranging a plurality of characters 16 in the tire circumferential direction. By these plurality of characters 16, either the manufacturer name, product name, brand, or the like is displayed. These characters 16 have a shape that can be clearly distinguished as to what kind of characters for the purpose of displaying the manufacturer name or the like. Also, each of the characters 16 is formed by being bordered by concave or convex lines.

[0022] As shown in FIGS. 2 and 3, the pattern 14 is formed by arranging a number of ridges 20 side by side in the tire circumferential direction while overlapping. When viewed from a direction perpendicular to the surface of the sidewall 10, all the ridges 20 are ellipses of the same shape and the same size. Also, all the ridges 20 are arranged such that the major axis faces the tire circumferential direction and the minor axis faces the tire radial direction.

[0023] In those ellipses, the length of the minor axis is 50% or more and less than 100% of the length of the major axis. The length of the ridge 20 in the tire radial direction (that is, the length of the minor axis of the ellipse) is 50% or more and 95% or less of the width HA in the tire radial direction of the decorative area 11.

[0024] Here, the ridge 20 is something that protrudes from the tire surface and extends long along the tire surface. This ridge 20 is also called a rib. As the cross-sectional shape in the direction orthogonal to the longitudinal direction of the ridge 20, there are a semi-circle (FIG. 4), a shape consisting of a semi-circle and a straight line below it (FIG. 5), a triangle (FIG. 6), a shape in which the apex of the triangle is rounded (FIG. 7), a trapezoid (FIG. 8), a rectangle (FIG. 9), and the like. Here, the shape in which the apex of the triangle is rounded (FIG. 7) 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. The lines depicted as the ridges 20 in FIGS. 2 and 3 are the center lines in the width direction of the ridges 20 (the lines at the positions indicated by T in FIGS. 4 to 9).

[0025] In any of the cross-sectional shapes of the ridge 20, the height H1 of the 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 any of the cross-sectional shapes of the ridge 20, the width W1 of the ridge 20 is 0.1 mm or more and 1.0 mm or less.

[0026] The rib 20 can be formed by a mold used during vulcanization molding. Here, for the rib 20 with a small height H1 and width W1, it can be formed by a mold with fine unevenness formed by laser processing.

[0027] Also, assuming the radius of the semi - circle in FIGS. 4 and 5 is R, the length H2 of the straight line of the rib 20 in the shape of FIG. 5 composed of a semi - circle and a straight line in the cross - sectional shape is (the height H1 of the rib 20)-(the radius R of the semi - circle). Further, in the trapezoidal rib 20 of 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 rib 20).

[0028] In all the ribs 20 in one pattern 14, their centers are provided on one reference line 21. Here, the center of the rib 20 is the intersection of the major axis and the minor axis of the ellipse. Also, 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.

[0029] 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. Also, 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 around the tire rotation axis.

[0030] As shown in FIG. 10, a plurality of reference points 22 are set at equal intervals on this reference On line 21 line. The reference points 22 are not actually drawn but are virtual points. And as shown in FIG. 11, the centers of the ribs 20 are arranged at each reference point 22. Note that FIGS. 10 and 11 are diagrams shown in a simplified manner for explanation, and the curvature of the reference Line 2 line 1, the interval between the reference points 22, the number of ribs 20, etc. are different from FIGS. 2 and 3 、base 。 adjacent ​The distance P between the matching reference points 22 (see FIGS. 10 and 11) is 1% or more and 15% or less (preferably 5% or more and 15% or less) of the circumferential length LC of one rib 20 (see FIG. 11). Therefore, for one rib 20, six or more and 100 or less (preferably six or more and 20 or less) other ribs 20 arranged on one side in the tire circumferential direction overlap the rib 20. 。 adjacent The specific numerical value of the distance P between the matching reference points 22 is, for example, 0.3 mm or more and 3.0 mm or less. In that case, the interval between adjacent ribs 20 is also 0.3 mm or more and 3.0 mm or less. Such ribs 20 is added are formed by a mold used in sulfur molding. 。adjacent When the interval between the matching ribs 20 is narrow, it can be formed by a mold with fine unevenness formed by laser processing. 。 ta When the decorative regions 11 are provided on both sides in the tire axial direction, the features of such ribs 20 are common in the decorative regions 11 on both sides in the tire axial direction.

[0031] As described above, in the pneumatic tire 1 of the embodiment, a reference line 21 extending in the tire circumferential direction and a plurality of reference points 22 provided on the reference line 21 are set on the sidewall 10, and annular ribs 20 centered on the respective reference points 22 are provided. And the plurality of ribs 20 have the same shape and overlap each other to form a pattern 14 as a pattern. Since the annular ribs 20 of the same shape overlap each other and are arranged side by side in this way, a sense of depth is generated in the pattern 14, and this is a new visual effect in the pneumatic tire 1.

[0032] Here, since the rib 20 is elliptical, a sense of depth like a curved pipe is generated in the pattern 14, and this is a new visual effect in the pneumatic tire 1. Also, since the plurality of ribs 20 have the same size, a sense of depth is particularly felt in the pattern 14.

[0033] In addition, since the distance between adjacent reference points 22 is 1% or more and 15% or less of the circumferential length of the rib 20, the plurality of ribs 20 appear to overlap appropriately, creating a suitable sense of depth in the pattern 14. Also, since the distance between adjacent reference points 22 is the same for all reference points 22, a particularly beautiful sense of depth is felt in the pattern 14.

[0034] The above embodiments are examples, and the scope of the invention is not limited to the above embodiments. Various changes can be made to the above embodiments without departing from the spirit of the invention.

[0035] First, the shape drawn by the rib as a pattern is not limited to the oval shape of the above embodiment. When viewed from a direction perpendicular to the surface of the sidewall 10, the shape drawn by the rib may be annular. Among annular shapes, a preferable shape is the one called 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 rib is a curve). In addition to the oval shape of the above embodiment, the oval includes oblong, circular, oval, etc. The oval and oblong shapes include those that are long in the circumferential direction of the tire, those that are long in the radial direction of the tire, and those that are long in a direction inclined with respect to the circumferential direction of the tire. Also, the oval includes a closed curve formed by the intersection of the surface of a cone and a plane that completely crosses the cone.

[0036] Note that the center of the rib shall coincide with the centroid of the surface having the shape drawn by the rib. However, when the shape drawn by the rib is a shape whose center is defined mathematically, the center of the rib shall be determined according to that definition. The center of the rib determined in this way is provided on the reference line 21 of the sidewall 10.

[0037] As one of the modified examples of the shape drawn by the ribs, there is a perfect circle like the rib 120 in FIG. 12. For the perfect circular rib 120, the cross-sectional shape, height, width, the length of the rib 120 in the tire diameter direction with respect to the width HA of the decorative region 11 in the tire diameter direction, the center position of the rib 120, and the interval between adjacent ribs 120 are the same as those of the elliptical rib 20. When the perfect circular ribs 120 are arranged while overlapping, a visual effect like seeing a curved pipe is produced.

[0038] Also, the size of the ribs may vary depending on the location. For example, the plurality of ribs 120 in FIG. 13 are all perfect circles, but their sizes gradually change in the tire circumferential direction. The radius of the rib 120 in FIG. 13 is the largest at the maximum points 118 provided at equal intervals at a plurality of locations in the tire circumferential direction, and the smallest at the minimum point 119 provided between the two maximum points 118. And from the maximum point 118 to the minimum point 119, the radius of the rib 120 gradually changes. Thereby, a visual effect different from when the sizes of all the ribs are the same is produced.

[0039] The radius of the rib 120 at the minimum point 119 is 45% or more and 75% or less of the radius of the rib 120 at the maximum point 118. Also, the interval between adjacent ribs 120 is 1% or more and 15% or less (preferably 5% or more and 15% or less) of the length of the rib 120 at the maximum point 118 in the tire circumferential direction.

[0040] When the size of the ribs gradually changes in the tire circumferential direction in this way, the number of maximum points and the number of minimum points are not limited. For example, there may be only one maximum point and one minimum point in one pattern 14. Also, the length in the tire circumferential direction from the maximum point to the minimum point varies. In the upper pattern 14 of FIG. 13, the left end is the maximum point 118 and the right end is the minimum point 119, but there may also be cases where the left end is the minimum point and the right end is the maximum point, cases where both the left and right ends are the maximum points, and cases where both the left and right ends are the minimum points.

[0041] Also, similar to the circular convex ribs 120, for the elliptical convex ribs, the size (specifically, the length in the tire radial direction) may gradually change in the tire circumferential direction between the maximum point and the minimum point in the same way. The length of the convex rib in the tire radial direction at the minimum point is 45% or more and 75% or less of the length of the convex rib in the tire radial direction at the maximum point.

[0042] Also, as shown in FIGS. 14 and 15, the intervals between adjacent convex ribs 120 may change in the tire circumferential direction. In FIG. 14, a narrow location X and a wide location Y of the intervals between adjacent convex ribs 120 are alternately repeated in the tire circumferential direction. The wide location Y of the intervals between adjacent convex ribs 120 has an interval twice that of the narrow location X.

[0043] Also, in FIG. 15, a narrow location X, an intermediate location Z, and a wide location Y of the intervals between adjacent convex ribs 120 are repeated in this order in the tire circumferential direction. Based on the narrow location X of the intervals between adjacent convex ribs 120, the intermediate location Z has an interval twice as large, and the wide location Y has an interval five times as large.

[0044] Note that for the elliptical convex ribs, similar to FIGS. 14 and 15, the intervals between adjacent convex ribs may change in the tire circumferential direction.

[0045] Also, the number of patterns 14 provided for one sidewall 10 is not limited. For example, similar to the circular patterns 14 in FIGS. 12 and 13, a pattern 14 composed of elliptical convex ribs 20 as shown in FIG. 2 may also be provided at two opposing locations in the decorative region 11.

[0046] Also, in the modified example of FIG. 16, between the labelings 15, two patterns 14 separated in the tire circumferential direction are arranged side by side in the tire circumferential direction. And a total of four patterns 14 are provided for one sidewall 10.

[0047] Alternatively, the pattern 14 may be formed by concave stripes instead of convex stripes. Here, the concave stripe refers to a depression on the tire surface that extends long along the tire surface. As the cross-sectional shape in the direction orthogonal to the longitudinal direction of the concave stripe, there can be various shapes such as a triangle, a trapezoid, a rectangle, a semi-circle, etc. A convex stripe or a concave stripe that draws an annular line such as an ellipse when viewed from a direction perpendicular to the surface of the sidewall 10 shall be referred to as an annular pattern.

[0048] Also, as shown in FIG. 17, a strip-shaped region 27 in which a plurality of convex stripes 26 extending in the tire radial direction are arranged at equal intervals in the tire circumferential direction may be provided on the outer side in the tire radial direction of the decorative region 11. The plurality of convex stripes 26 are arranged at equal intervals with an interval of 0.3 mm or more and 1.0 mm or less in the tire circumferential direction. The strip-shaped region 27 may be provided in a part of the tire circumferential direction, or may be provided over the entire circumference in the tire circumferential direction. The strip-shaped region 27 is adjacent to the outside of the decorative region 11. The dimension in the tire radial direction of the strip-shaped region 27 is preferably 5 mm or more and 12 mm or less.

[0049] By providing such a strip-shaped region 27, the interface unevenness and bare areas between the members of the tread rubber 6 and the sidewall rubber 7 can be suppressed. Further, a black strip-shaped region is formed by the light attenuation effect due to the provision of the convex stripes 26, and the decorative region 11 can be made prominent.

Explanation of Signs

[0050] C…Center line, 1…Pneumatic tire, 2…Carcass ply, 2a…Folded-back portion, 2b…Turned-up end, 3…Rubber chafer, 4…Belt, 5…Belt reinforcing layer, 6…Tread rubber, 7…Sidewall rubber, 8…Inner liner, 9…Bead portion, 10…Sidewall, 11…Decorative region, 12…Inner diameter side line, 13…Outer diameter side line, 14…Pattern, 15…Labeling, 16…Characters, 20…Convex stripe, 21…Reference line, 22…Reference point, 26…Convex stripe, 27…Strip-shaped region, 118…Maximum point, 119…Minimum point, 120…Convex stripe

Claims

1. In a pneumatic tire having a pattern formed on a sidewall, a reference line extending in the tire circumferential direction and a plurality of reference points provided on the reference line are set on the sidewall, an annular pattern centered on each of the reference points is provided, and the plurality of annular patterns have the same shape and overlap each other to form the pattern, The pneumatic tire, wherein the shape of the annular pattern is oval.

2. The pneumatic tire according to claim 1, wherein the plurality of annular patterns have the same size.

3. The pneumatic tire according to claim 1 or 2, wherein the sizes of the plurality of annular patterns are different, and the ratio of the length in the tire radial direction of the smaller annular pattern to the length in the tire radial direction of the larger annular pattern is 0.45 or more and 0.75 or less.

4. The pneumatic tire according to claim 3, wherein the sizes of the plurality of annular patterns gradually change in the tire circumferential direction.

5. The pneumatic tire according to any one of claims 1 to 4, wherein the distance between adjacent reference points is 1% or more and 15% or less of the length in the tire circumferential direction of the annular pattern.

6. The pneumatic tire according to any one of claims 1 to 5, wherein the distance between adjacent reference points is the same among all the reference points.

7. The pneumatic tire according to any one of claims 1 to 5, wherein the distance between adjacent reference points changes in the tire circumferential direction.

8. 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 pattern is provided, and a region having a dimension in the tire radial direction of 5 mm or more and 12 mm or less is provided. The pneumatic tire according to any one of claims 1 to 7.

9. The pneumatic tire according to any one of claims 1 to 8, wherein the annular pattern is a rib protruding from the tire surface.

Images