Pneumatic tires

Abstract

To provide a pneumatic tire in which visual effects are generated.SOLUTION: A pneumatic tire 1 is provided with patterns on each of side walls 10. The side wall 10 of the pneumatic tire 1 comprises: a plurality of reference points 22 arranged like a spiral; and a plurality of circular patterns 20 each forming a circle centered on the reference point 22. Among the circular patterns 20, the farther on a spiral outer side, each reference point 22 thereof is located, the larger, each radius thereof is. Each circular pattern 20 centered on the reference point 22 on a spiral inner side, is configured to inscribe each circular pattern 20 centered on the reference point 22 on an immediately outer side.SELECTED DRAWING: Figure 2

Description

[Technical field]

[0001] The present invention relates to a pneumatic tire. [Background technology]

[0002] For example, a pneumatic tire having a pattern on the sidewall is known, as described in Patent Document 1. The pattern is formed by arranging a large number of ridges.

[0003] Many of the conventional patterns have many linear ridges arranged at equal intervals. In addition, as disclosed in Patent Document 1, a pattern with curved ridges arranged at equal intervals is also known. Either pattern enhances the design of the sidewall. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] JP 2014-180947 A Summary of the Invention [Problem to be solved by the invention]

[0005] Incidentally, while beautiful patterns are frequently proposed, there have not been many proposals for groundbreaking patterns that produce unprecedented visual effects.

[0006] Therefore, an object of the present invention is to provide a pneumatic tire that creates a visual effect. [Means for solving the problem]

[0007] In one embodiment, a pneumatic tire has a pattern on a sidewall, and the sidewall is provided with a plurality of reference points arranged in a spiral shape and a plurality of circular patterns that draw circles centered on each of the reference points, the circular patterns having a larger radius the reference points that are closer to the outside of the spiral, and the circular pattern centered on the reference point on the inside of the spiral is inscribed in the circular pattern centered on the reference point just outside it. Effect of the Invention

[0008] The pneumatic tire of the embodiment has the above-mentioned characteristics, thereby producing a visual effect that gives a sense of three-dimensionality. [Brief description of the drawings]

[0009] [Figure 1] FIG. 2 is a half cross-sectional view of a pneumatic tire taken in an axial direction. [Diagram 2] A view of the decorative area of ​​the sidewall from the axial direction of the tire. [Diagram 3] Enlarged image of the small pattern. [Figure 4] Cross-sectional view of a convex strip (when the cross-sectional shape is semicircular). [Diagram 5] Cross-sectional view of a convex rib (when the cross-sectional shape consists of a semicircle and a straight line below it). [Figure 6] Cross-sectional view of a convex strip (when the cross-sectional shape is triangular). [Figure 7] Cross-sectional view of a convex rib (when the cross-sectional shape is a triangle with rounded apexes). [Figure 8] Cross-sectional view of a convex strip (when the cross-sectional shape is trapezoidal). [Figure 9] Cross-sectional view of a convex strip (when the cross-sectional shape is rectangular). [Figure 10] FIG. 2 is a cross-sectional view of the ridges at the contact position of the two ridges. [Figure 11] FIG. 2 is a cross-sectional view of the ridges at the contact position of the two ridges. [Figure 12] FIG. 2 is a cross-sectional view of the ridges at the contact position of the two ridges. [Figure 13]FIG. 13 is a view of the decorative area of ​​the sidewall of a modified example, viewed from the tire axial direction. [Figure 14] FIG. 13 is a view of the decorative area of ​​the sidewall of a modified example, viewed from the tire axial direction. [Figure 15] FIG. 13 is a view of the decorative area of ​​the sidewall of a modified example, viewed from the tire axial direction. [Figure 16] FIG. 13 is a view of the decorative area of ​​the sidewall of a modified example, viewed from the tire axial direction. [Figure 17] FIG. 4 is a partial enlarged view of a decorative area and an area radially outboard of the decorative area; DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0010] 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. A cross-sectional structure of the pneumatic tire 1 of the embodiment is shown in Fig. 1. Note that Fig. 1 shows only half of the tire in the axial direction, and the actual pneumatic tire 1 is substantially symmetrical with respect to the center line C.

[0011] The pneumatic tire 1 has bead portions 9 on both axial sides of the tire. The bead portions 9 each include a bead core made of a steel wire wound in a circular shape, and a rubber bead filler provided radially outside the bead core.

[0012] One or two carcass plies 2 are laid across the bead portions 9 on both axial sides of the tire. The carcass ply 2 is a sheet-like member in which numerous ply cords arranged in a direction perpendicular to the tire circumferential direction are covered with rubber. The carcass ply 2 forms the framework of the pneumatic tire 1 between the bead portions 9 on both axial sides of the tire, and wraps the bead portions 9 by being folded back and wound up around the bead portions 9 from the axially inner side to the axially outer side. In addition, a rubber chafer 3 is provided at a location on the axially outer side of the folded back portion 2a of the carcass ply 2.

[0013] Furthermore, one or more 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 made of many steel cords covered with rubber. The belt reinforcing layer 5 is a member made of many organic fiber cords covered with rubber. A tread rubber 6 is provided on the radially outer side of the belt reinforcing layer 5. The tread rubber 6 has many grooves formed therein to form a tread pattern.

[0014] In addition, sidewall rubber 7 is provided on both sides of the carcass ply 2 in the tire axial direction. The tread rubber 6 and the sidewall rubber 7 overlap at the buttresses, but either the tread rubber 6 or the sidewall rubber 7 may overlap on the tire surface side. The radially inner portion of the sidewall rubber 7 extends close to the bead portion 9 and covers a part of the rubber chafer 3. In this embodiment, the sidewall 10 refers to not only the portion of the sidewall rubber 7 that appears on the tire surface, but also the entire area that can be seen when the pneumatic tire 1 is viewed from the tire axial direction.

[0015] 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 components, components such as an underbelt pad and a chafer are provided according to the functional needs of the tire.

[0016] As shown in FIG. 1, a decorative area 11 is provided on at least one of the sidewalls 10 on both sides in the tire axial direction. As shown in FIG. 2, the decorative area 11 is in the shape of a ring centered on the tire rotation axis. The decorative area 11 is an area of ​​a constant width sandwiched between a small-diameter circular inner diameter side line 12 and a 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 by a concave, convex or step on the tire surface, or may be imaginary lines that do not actually exist. The tire radial width HA of the decorative area 11 is 5% to 60% (preferably 10% to 35%) of the tire cross-sectional height H (the tire radial length from the inner diameter end to the outer diameter surface of the pneumatic tire 1).

[0017] The location of the decorative area 11 in the tire radial direction is a location that includes the position of the maximum width of the pneumatic tire 1. Here, the position of the maximum width of the pneumatic tire 1 refers to the position where the length in the tire axial direction from the surface of one sidewall 10 on the axial side of the tire to the surface of the other sidewall 10 on the axial side of the tire is the longest.

[0018] 1, the decorative region 11 is provided in a manner including a place where the interface between the tread rubber 6 and the sidewall rubber 7 appears on the tire surface. In this manner, the decorative region 11 is preferably provided in a manner including a place where steps are likely to appear on the surface of the sidewall 10. The place where steps are likely to appear on the surface of the sidewall 10 is typically the end of a tire constituent member. Typical such places include, in addition to the above-mentioned place where the interface between the tread rubber 6 and the sidewall rubber 7 appears on the tire surface, a place in the tire axial direction of the turned-up end 2b of the carcass ply 2 (the end of the turned-up portion 2a of the carcass ply 2), for example.

[0019] 2, labelings 15 are provided at two opposing locations in the annular decorative area 11. Furthermore, patterns 14 are provided at two locations between the two labelings 15. As a result, the labelings 15 and the patterns 14 are alternately arranged in the tire circumferential direction.

[0020] In order to leave a sufficient distance between adjacent labelings 15 and patterns 14, the minimum value of the distance LB between the labelings 15 and patterns 14 (the length in the tire circumferential direction from one end of the labeling 15 to the other end of the pattern 14) is set to 3 mm. In addition, in order to ensure a sufficient area for the pattern 14, the maximum value of the distance LB between the labelings 15 and patterns 14 is set to 60% of the length LA of the labelings 15 in the tire circumferential direction (the length from one end of the labeling 15 in the tire circumferential direction to the other end of the labeling 15 in the tire circumferential direction).

[0021] The labeling 15 is formed by a plurality of characters 16 arranged in the circumferential direction of the tire. The plurality of characters 16 indicate the manufacturer's name, product name, brand, etc. These characters 16 are shaped to be clearly identifiable in order to indicate the manufacturer's name, etc. Furthermore, each character 16 is formed with a concave or convex line bordering it.

[0022] 2 and 3, the pattern 14 includes many ridges 20. When viewed from a direction perpendicular to the surface of the sidewall 10, each ridge 20 is a perfect circle. A plurality of ridges 20 (preferably five or more) of different sizes are gathered together to form one small pattern 25. All of the ridges 20 that form one small pattern 25 are different in size.

[0023] In the small patterns 25, smaller ridges 20 are arranged inside larger ridges 20 (i.e., with a larger radius). The smaller ridges 20 are inscribed in the larger ridges 20 immediately outside of it. Inscribed in a circle means that two circles share a point and one circle is inside the other. The pattern 14 is formed by lining up multiple such small patterns 25 in the tire circumferential direction. The length of the small patterns 25 in the tire radial direction (i.e., the diameter of the largest ridge 20) is 50% to 95% of the width HA of the decorative area 11 in the tire radial direction.

[0024] Here, the convex streak 20 refers to a portion that protrudes from the tire surface and extends long along the tire surface. The convex streak 20 is also called a ridge. The cross-sectional shape of the convex streak 20 in a direction perpendicular to the longitudinal direction can be a semicircle (FIG. 4), a shape consisting of a semicircle and a straight line below it (FIG. 5), a triangle (FIG. 6), a shape with rounded apexes of a triangle (FIG. 7), a trapezoid (FIG. 8), a rectangle (FIG. 9), etc. Here, the shape with rounded apexes of a triangle (FIG. 7) is a type of triangle. Although not shown, there may also be shapes that are slight modifications of these cross-sectional shapes, such as a sawtooth shape that is obtained by deforming the triangle in FIG. 6 by tilting it.

[0025] 2 and 3 as the ridges 20 is the center line of the ridges 20 in the width direction (the line at the position indicated by T in Figs. 4 to 9). The radius and diameter of the ridges 20 are determined based on the center line of the ridges 20 in the width direction. The radius and diameter of the ridges 20 refer to the radius and diameter of a perfect circle formed by the ridges 20.

[0026] Regardless of the cross-sectional shape 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). Moreover, regardless of the cross-sectional shape of the ridge 20, the width W1 of the ridge 20 is 0.1 mm or more and 1.0 mm or less.

[0027] The protrusions 20 can be formed by a mold used during vulcanization molding. Here, the protrusions 20 having a small height H1 and width W1 can be formed by a mold in which fine projections and recesses are formed by laser processing.

[0028] 4 and 5 has a radius R, the length H2 of the straight line of the convex rib 20 in the shape of Fig. 5, whose cross-sectional shape is a semicircle and a straight line, is (height H1 of the convex rib 20) - (radius R of the semicircle). In the trapezoidal convex rib 20 in Fig. 8, the length W2 of the upper base is 20% to 50% of the length of the lower base (i.e., width W1 of the convex rib 20).

[0029] In the small pattern 25, a single spiral reference line (not shown) is set. A plurality of reference points 22 (see FIG. 3) are set on the reference line. Since the reference line is spiral, the plurality of reference points 22 are arranged in a spiral shape. The reference line and the reference points 22 are not actually formed by unevenness or the like in the decorative area 11, but are virtual. A protruding stripe 20 is provided for each of these reference points 22. Specifically, the center of the circular protruding stripe 20 is located at each of the reference points 22.

[0030] Here, the straight-line distance P (not shown in the figure) between two adjacent reference points 22 on the reference line increases as it goes further outside the spiral drawn by the reference line (away from the center of the spiral). That is, considering three reference points 22a, 22b, and 22c (see Fig. 3) provided in order from the inner side (closer to the center of the spiral) to the outer side of the said spiral, there is a relationship of P1 < P2 between the straight-line distance P1 between the two inner reference points 22a and 22b and the straight-line distance P2 between the two outer reference points 22b and 22c. However, it is preferable that P2 is not more than twice P1.

[0031] The radius of the rib 20 is larger for the rib 20 centered on the outer side of the spiral (the spiral drawn by the reference line). And, the rib 20 centered on the inner reference point 22 of the two adjacent reference points 22 on the reference line (hereinafter referred to as the "inner rib 20") and the rib 20 centered on the outer reference point 22 of the same two reference points 22 (hereinafter referred to as the "outer rib 20") are in contact. However, the inner rib 20 does not protrude outside the outer rib 20. That is, the inner rib 20 is inscribed in the outer rib 20. Also, for all the ribs 20 belonging to the same small pattern 25, the inner rib 20 is inscribed in its outer rib 20.

[0032] Here, "being in contact" means any one of the following: the two ribs 20 overlap and integrate as shown in Fig. 10 at the contact position, a part of the two ribs 20 overlap as shown in Fig. 11, and there is no gap between the two ribs 20 as shown in Fig. 12.

[0033] When the straight-line distance between two adjacent reference points 22 on the reference line is P, the radius of the outer rib 20 among the ribs 20 centered on these two reference points 22 is preferably the value obtained by adding P to the radius of the inner rib 20 among the ribs 20 centered on the same two reference points 22. When this preferable relationship holds, the inner rib 20 is accurately inscribed in the outer rib 20.

[0034] As described above, the reference points 22 that are the centers of the ridges 20 are arranged in a spiral shape, so that all the ridges 20 are arranged to draw a spiral. Smaller ridges 20 are located closer to the inside of the spiral, and larger ridges 20 are located closer to the outside of the spiral. In addition, as shown in Figure 3, the contact points 23 between the inner ridges 20 and the outer ridges 20 are also arranged to draw a single spiral.

[0035] The diameter of the ridge 20 with the smallest radius in the small pattern 25 (hereinafter referred to as the "smallest ridge 20a") is 10% to 50% of the width HA in the tire radial direction of the decorative area 11. This allows a sufficient number of ridges 20 to fit in the decorative area 11.

[0036] In places away from the contact point 23 between the inner convex rib 20 and the outer convex rib 20 (i.e., places where the inner convex rib 20 and the outer convex rib 20 are separated), a wide plane exists between the two convex ribs 20, so that the light that strikes it is reflected as a mirror or something similar. On the other hand, at the contact point 23 between the inner convex rib 20 and the outer convex rib 20, the light that strikes it is diffusely reflected.

[0037] As a result, areas away from the contact points 23 between the inner ridges 20 and the outer ridges 20 appear bright, and the contact points 23 between the inner ridges 20 and the outer ridges 20 appear dark. As described above, the contact points 23 between the inner ridges 20 and the outer ridges 20 are arranged in a spiral shape, so it appears as if there is a black spiral connecting the contact points 23.

[0038] As shown in Fig. 2, the above-mentioned minimum ridge streaks 20a are biased to one side in the tire circumferential direction from the center of the small patterns 25 (i.e., the center of the ridge streaks 20 with the largest radius in the small patterns 25). Here, biased means that the center of the minimum ridge streaks 20a is shifted in one direction from the center of the small patterns 25. As shown in Fig. 2, in the entire decorative region 11, all of the minimum ridge streaks 20a are biased to one side in the tire circumferential direction from the center of the small patterns 25. The direction of bias is indicated by arrow D in Fig. 2.

[0039] When the decorative regions 11 are provided on both axial sides of the tire, the features of the convex stripes 20 are common to the decorative regions 11 on both axial sides of the tire.

[0040] As described above, in the pneumatic tire 1 of the embodiment, the sidewall 10 is provided with a plurality of reference points 22 arranged in a spiral shape, and a plurality of circular convex stripes 20 centered on each of the reference points 22. The convex stripes 20 centered on the reference points 22 located further outward in the spiral have a larger radius, and the convex stripes 20 centered on the reference point 22 on the inside of the spiral are inscribed in the convex stripes 20 centered on the reference point 22 on the outside.

[0041] In this way, multiple circular ridges 20 of different sizes are provided, and small ridges 20 are provided inside larger ridges 20, so that the small pattern 25 made up of these ridges 20 creates a visual effect that gives a sense of three-dimensionality. Also, since the center of each ridge 20 is provided at the reference point 22 that is arranged in a spiral, multiple ridges 20 of different sizes are arranged in a spiral, creating a visual effect that gives a sense of three-dimensionality like looking at a conch shell.

[0042] In addition, the inner ridges 20 come into contact with the outer ridges 20, and the contact points 23 appear dark. And because the contact points 23 between the inner ridges 20 and the outer ridges 20 are arranged in a spiral shape, the small pattern 25 creates the visual effect of a black spiral.

[0043] In addition, the linear distance between adjacent reference points 22 on the spiral becomes larger toward the outside of the spiral. And since the protrusions 20 are provided with respect to the reference points 22 arranged in this manner, it is easy to recognize how the protrusions 20 are arranged in a spiral shape.

[0044] Moreover, in the entire decorative region 11, all of the smallest convex stripes 20a are biased toward one side in the tire circumferential direction from the center of the small patterns 25. This creates a visual effect in which all of the small patterns 25 face in the same direction in the tire circumferential direction.

[0045] The above-described embodiment is merely an example, and the scope of the invention is not limited to the above-described embodiment. Various modifications can be made to the above-described embodiment without departing from the spirit of the invention.

[0046] For example, the linear distance between two adjacent reference points 22 on one spiral reference line may be equal between all the reference points 22 in one small pattern 25 .

[0047] In addition, there may be various patterns of the bias direction of the minimum convex stripes 20a in the small pattern 25. For example, as shown in FIG. 13, all the minimum convex stripes 20a of the two patterns 14 may be biased toward the same labeling 15 (the labeling 15 on the left side in FIG. 13). As shown in FIG. 14, all the minimum convex stripes 20a of the two patterns 14 may be biased toward the closer labeling 15. As shown in the upper pattern 14 in FIG. 15, the bias direction of the minimum convex stripes 20a may alternate in the tire circumferential direction. In FIG. 15, two small patterns 25 with close minimum convex stripes 20a look like a pair of eyes. Note that the arrow D in FIG. 13 to FIG. 15 indicates the bias direction of the minimum convex stripes 20a.

[0048] Furthermore, when many ridges 20 are provided in one small pattern 25, the ridges 20b having a large radius may not be contained within the decorative area 11 as shown in FIG. 16 and may be interrupted.

[0049] Further, in the above embodiment, two patterns 14 are provided for one sidewall 10, but one or three or more patterns 14 may be provided for one sidewall 10.

[0050] Also, the pattern 14 may be formed by grooves instead of protrusions. Here, the grooves are recessed into the tire surface and extend long along the tire surface. The cross-sectional shape of the grooves in a direction perpendicular to the longitudinal direction may be various, such as triangular, trapezoidal, rectangular, semicircular, etc. A protrusion or groove that draws a circular line when viewed from a direction perpendicular to the surface of the sidewall 10 is referred to as a circular pattern.

[0051] 17, a band-shaped region 27 may be provided on the tire radial outer side of the decorative region 11, in which a plurality of ridges 26 extending in the tire radial direction are arranged at equal intervals in the tire circumferential direction. The plurality of ridges 26 are arranged at equal intervals in the tire circumferential direction at intervals of 0.3 mm or more and 1.0 mm or less. The band-shaped region 27 may be provided in a portion of the tire circumferential direction, or may be provided over the entire tire circumferential direction. The band-shaped region 27 is adjacent to the outer side of the decorative region 11. The tire radial dimension of the band-shaped region 27 is preferably 5 mm or more and 12 mm or less.

[0052] Providing such a belt-like region 27 can suppress unevenness and bareness at the interface between the tread rubber 6 and the sidewall rubber 7. In addition, the provision of the protrusions 26 has a light attenuation effect, forming a black belt-like region, which makes the decorative region 11 stand out. [Explanation of symbols]

[0053] C...center line, 1...pneumatic tire, 2...carcass ply, 2a...folded-up 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 area, 12...inner diameter side line, 13...outer diameter side line, 14...pattern, 15...labeling, 16...letter, 20...ridge, 20a...smallest ridge, 20b...large ridge, 22...reference point, 23...contact point, 25...small pattern, 26...ridge, 27...band-shaped area

Claims

1. In a pneumatic tire having a pattern on the sidewall, The sidewall is provided with a plurality of reference points arranged in a spiral shape and a plurality of circular patterns each of which draws a circle centered on each of the reference points; The circular pattern has a larger radius as the reference point serving as the center is located on the outer side of the spiral. The circular pattern centered on the reference point inside the spiral is inscribed in the circular pattern centered on the reference point immediately outside it. A pneumatic tire characterized by:

2. The pneumatic tire according to claim 1 , wherein a linear distance between adjacent reference points on the spiral increases toward the outside of the spiral.

3. The pneumatic tire according to claim 1 , wherein the linear distances between adjacent reference points on the spiral are equal.

4. 4. The pneumatic tire according to claim 1, wherein, when the straight-line distance between two adjacent reference points on the spiral is P, the radius of the circular pattern having the outer reference point of the two reference points as its center is a value obtained by adding P to the radius of the circular pattern having the inner reference point of the two reference points as its center.

5. The pneumatic tire according to any one of claims 1 to 4, wherein a cross-sectional shape of the circular pattern includes a triangle, a trapezoid, a rectangle, or a semicircle.

6. The pneumatic tire according to any one of claims 1 to 5, wherein a region in which a plurality of ridges extending in the tire radial direction are arranged at equal intervals in the tire circumferential direction is provided on the sidewall, radially outward of the decorative region in which the circular pattern is provided, the region having a dimension in the tire radial direction of 5 mm or more and 12 mm or less.

7. The pneumatic tire according to any one of claims 1 to 6, wherein the circular pattern is a protrusion protruding from a tire surface.

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