JP7650754B2 - Pneumatic tires - Google Patents

Description

The present invention relates to a pneumatic tire.

For example, as described in Patent Document 1, a pneumatic tire is known that has a pattern on the sidewall. The pattern is formed by a large number of ridges lined up.

Most conventional patterns have numerous linear ridges arranged at equal intervals. In addition, as disclosed in Patent Document 1, patterns with curved ridges arranged at equal intervals are also known. Either pattern enhances the design of the sidewall.

JP 2014-180947 A

By the way, while beautiful patterns are frequently proposed, there have not been many proposals for groundbreaking patterns that produce unprecedented visual effects.

Therefore, the objective of the present invention is to provide a pneumatic tire that creates a visual effect.

The pneumatic tire of the embodiment is characterized in that, 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 drawing a circle centered on each of the reference points, the circular patterns have a larger radius the reference points are on the outer side of the spiral, and the circular pattern centered on the reference point on the inner side of the spiral is inscribed in the circular pattern centered on the reference point immediately outside it.

The pneumatic tire of the embodiment has the above characteristics, which creates a visual effect that gives a sense of three-dimensionality.

FIG. 2 is a half cross-sectional view of a pneumatic tire taken in an axial direction. A view of the decorative area of the sidewall from the axial direction of the tire. Enlarged image of the small pattern. Cross-sectional view of a convex strip (when the cross-sectional shape is semicircular). Cross-sectional view of a convex rib (when the cross-sectional shape is a semicircle with a straight line below it). Cross-sectional view of a convex strip (when the cross-sectional shape is triangular). Cross-sectional view of a convex rib (when the cross-sectional shape is a triangle with rounded apexes). Cross-sectional view of a convex strip (when the cross-sectional shape is trapezoidal). Cross-sectional view of a convex strip (when the cross-sectional shape is rectangular). FIG. 4 is a cross-sectional view of the ridges at a contact position of the two ridges. FIG. 4 is a cross-sectional view of the ridges at a contact position of the two ridges. FIG. 4 is a cross-sectional view of the ridges at a contact position of the two ridges. FIG. 13 is a view of the decorative area of the sidewall of a modified example, viewed from the tire axial direction. FIG. 13 is a view of the decorative area of the sidewall of a modified example, viewed from the tire axial direction. FIG. 13 is a view of the decorative area of the sidewall of a modified example, viewed from the tire axial direction. FIG. 13 is a view of the decorative area of the sidewall of a modified example, viewed from the tire axial direction. FIG. 4 is a partial enlarged view of a decorative area and an area radially outboard of the decorative area;

The pneumatic tire 1 of the embodiment has a structure similar to that of a typical radial tire, except for the sidewall structure. Figure 1 shows the cross-sectional structure of the pneumatic tire 1 of the embodiment. Note that Figure 1 shows only half of the tire in the axial direction, and the actual pneumatic tire 1 is approximately symmetrical with respect to the center line C.

In the pneumatic tire 1, bead portions 9 are provided on both sides of the tire in the axial direction. The bead portions 9 consist of a bead core made of a steel wire wound in a circle and a rubber bead filler provided on the radial outside of the bead core.

One or two carcass plies 2 are laid across the bead portions 9 on both sides in the axial direction 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 skeleton shape of the pneumatic tire 1 between the bead portions 9 on both sides in the axial direction of the tire, and wraps the bead portions 9 by folding back and rolling up from the inside to the outside in the axial direction of the tire around the bead portions 9. In addition, a rubber chafer 3 is provided at the location on the outside in the axial direction of the folded back portion 2a of the carcass ply 2.

In addition, 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. Tread rubber 6 is provided on the radially outer side of the belt reinforcing layer 5. The tread rubber 6 has many grooves to form a tread pattern.

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.

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, other components such as underbelt pads and chafers are provided according to the functional needs of the tire.

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 a constant-width area 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 concavities, convexities, or steps on the tire surface, or may be virtual 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).

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 in the tire axial direction to the surface of the other sidewall 10 in the tire axial direction is the longest.

In addition, in FIG. 1, the decorative area 11 is provided in a manner that includes the location where the interface between the tread rubber 6 and the sidewall rubber 7 appears on the tire surface. In this way, it is preferable that the decorative area 11 is provided in a manner that includes the 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 the location of the end of a tire constituent member. Typical such locations include, in addition to the location where the interface between the tread rubber 6 and the sidewall rubber 7 appears on the tire surface as described above, for example, the location in the tire axial direction of the turned-up end 2b of the carcass ply 2 (the end of the folded-up portion 2a of the carcass ply 2).

As shown in FIG. 2, labeling 15 is provided at each of two opposing locations in the annular decorative area 11. Furthermore, patterns 14 are provided at each of the two locations sandwiched between the two labelings 15. As a result, the labeling 15 and the patterns 14 are arranged alternately in the circumferential direction of the tire.

To ensure sufficient spacing 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 the end of the labeling 15 to the end of the pattern 14) is set to 3 mm. Also, to ensure 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 labelings 15 in the tire circumferential direction to the other end of the labelings 15 in the tire circumferential direction).

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

As shown in Figures 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 group of multiple ridges 20 (preferably five or more) of different sizes form one small pattern 25. All of the ridges 20 that form one small pattern 25 are different in size.

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 tire radial length of the small patterns 25 (i.e., the diameter of the largest ridge 20) is 50% to 95% of the tire radial width HA of the decorative area 11.

Here, the convex streaks 20 are those that protrude from the tire surface and extend long along the tire surface. These convex streaks 20 are also called ridges. The cross-sectional shapes of the convex streaks 20 in a direction perpendicular to the longitudinal direction include semicircles (Figure 4), a shape consisting of a semicircle and a straight line below it (Figure 5), triangles (Figure 6), triangles with rounded apexes (Figure 7), trapezoids (Figure 8), and rectangles (Figure 9). Here, the triangles with rounded apexes (Figure 7) are a type of triangle. Although not shown, these cross-sectional shapes may also be slightly modified, such as a sawtooth shape that is a tilted deformation of the triangle in Figure 6.

The line depicted as the ridge 20 in Figures 2 and 3 is the center line of the ridge 20 in the width direction (the line at the position indicated by T in Figures 4 to 9). The radius and diameter of the ridge 20 are determined based on the center line of the ridge 20 in the width direction. The radius and diameter of the ridge 20 refer to the radius and diameter of the perfect circle described by the ridge 20.

Regardless of the cross-sectional shape of the convex rib 20, the height H1 of the convex rib 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). In addition, regardless of the cross-sectional shape of the convex rib 20, the width W1 of the convex rib 20 is 0.1 mm or more and 1.0 mm or less.

The convex ribs 20 can be formed using a mold used during vulcanization molding. Here, convex ribs 20 with small height H1 and width W1 can be formed using a mold in which fine irregularities are formed by laser processing.

If the radius of the semicircle in Figures 4 and 5 is R, then the length H2 of the straight line of the convex rib 20 in Figure 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 addition, in the trapezoidal convex rib 20 in Figure 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).

In the small pattern 25 described above, a single spiral reference line (not shown) is set. A number of reference points 22 (see FIG. 3) are set on this reference line. Because the reference line is spiral, the multiple reference points 22 are arranged in a spiral shape. Note that the reference line and reference points 22 are not actually formed by projections and recesses in the decorative area 11, but are virtual. A convex stripe 20 is provided for each of these reference points 22. Specifically, the center of the circular convex stripe 20 is located at each of the reference points 22.

Here, the straight-line distance P (not shown) between two adjacent reference points 22 on the reference line becomes larger the further out (away from the center of the spiral) the spiral is drawn by the reference line. In other words, considering three reference points 22a, 22b, 22c (see FIG. 3) arranged in order from the inside (closer to the center of the spiral) to the outside of the spiral, there is a relationship of P1<P2 between the straight-line distance P1 between the two inner reference points 22a, 22b and the straight-line distance P2 between the two outer reference points 22b, 22c. However, it is preferable that P2 is equal to or less than twice P1.

The radius of the convex stripe 20 is larger for convex stripes 20 that are centered on the outer side of the spiral (the spiral drawn by the reference line). The convex stripe 20 centered on the inner reference point 22 of the spiral among two adjacent reference points 22 on the reference line (hereinafter referred to as the "inner convex stripe 20") is in contact with the convex stripe 20 centered on the outer reference point 22 of the spiral among the same two reference points 22 (hereinafter referred to as the "outer convex stripe 20"). However, the inner convex stripe 20 does not extend outside the outer convex stripe 20. In other words, the inner convex stripe 20 is inscribed in the outer convex stripe 20. Furthermore, for all convex stripes 20 that belong to the same small pattern 25, the inner convex stripe 20 is inscribed in the outer convex stripe 20.

Here, contact means that at the contact position, the two ridges 20 overlap and become one as shown in FIG. 10, that parts of the two ridges 20 overlap as shown in FIG. 11, or that no gap is created between the two ridges 20 as shown in FIG. 12.

When the linear distance between two adjacent reference points 22 on the reference line is P, it is preferable that the radius of the outer convex rib 20 of the convex ribs 20 centered on these two reference points 22 is the radius of the inner convex rib 20 of the convex ribs 20 centered on the same two reference points 22 plus P. When this preferable relationship is established, the inner convex rib 20 is accurately inscribed in the outer convex rib 20.

As described above, the reference points 22 that are the centers of the ridges 20 are arranged in a spiral shape, so that all of the ridges 20 are arranged to form a spiral. Smaller ridges 20 are located on the inside of the spiral, and larger ridges 20 are located on the outside of the spiral. Also, as shown in Figure 3, the contact points 23 between the inner ridges 20 and the outer ridges 20 are arranged to form a single spiral.

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 tire radial width HA of the decorative area 11. This allows a sufficient number of ridges 20 to fit in the decorative area 11.

At locations away from the contact point 23 between the inner convex rib 20 and the outer convex rib 20 (i.e., locations 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 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.

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, so there appears to be a black spiral connecting the contact points 23.

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

When decorative regions 11 are provided on both sides of the tire in the axial direction, the characteristics of the ridges 20 are common to the decorative regions 11 on both sides of the tire in the axial direction.

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 ridges 20 centered on each of the reference points 22. The ridges 20 centered on the reference points 22 located further outward in the spiral have a larger radius, and the ridges 20 centered on the reference points 22 on the inside of the spiral are inscribed in the ridges 20 centered on the reference points 22 on the outside.

In this way, multiple circular ridges 20 of different sizes are provided, and smaller ridges 20 are provided inside larger ridges 20, so the small pattern 25 made up of these ridges 20 creates a visual effect that gives a sense of three-dimensionality. Also, because the center of each ridge 20 is located 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.

In addition, the inner ridge 20 is in contact with the outer ridge 20, and the contact points 23 appear dark. And because the contact points 23 between the inner ridge 20 and the outer ridge 20 are arranged in a spiral shape, a visual effect is created in which the small pattern 25 looks like a black spiral.

In addition, the linear distance between adjacent reference points 22 on the spiral is greater the further out on the spiral the point is. And because the protrusions 20 are provided with respect to the reference points 22 arranged in this way, it is easy to see how the protrusions 20 are arranged in a spiral shape.

In addition, in the entire decorative area 11, all of the smallest ridges 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.

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

For example, the straight-line distance between two adjacent reference points 22 on a single spiral reference line may be equal between all reference points 22 in one small pattern 25.

Also, there can be various patterns for the direction of bias of the minimum ridges 20a within the small patterns 25. For example, as shown in FIG. 13, all of the minimum ridges 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 of the minimum ridges 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 direction of bias of the minimum ridges 20a may alternate in the tire circumferential direction. In FIG. 15, two small patterns 25 with close minimum ridges 20a look like a pair of eyes. Note that the arrow D in FIG. 13 to FIG. 15 indicates the direction of bias of the minimum ridges 20a.

In addition, if many ridges 20 are provided in one small pattern 25, the ridges 20b with a large radius may not fit within the decorative area 11 and may be interrupted, as shown in Figure 16.

In addition, in the above embodiment, two patterns 14 are provided on one sidewall 10, but one or three or more patterns 14 may be provided on one sidewall 10.

The pattern 14 may also be formed by concave stripes instead of convex stripes. A concave stripe is a strip that is recessed into the tire surface and extends long along the tire surface. The cross-sectional shape of the concave stripe in a direction perpendicular to the longitudinal direction can be a variety of shapes, such as a triangle, trapezoid, rectangle, or semicircle. A convex stripe or concave stripe that forms a circular line when viewed perpendicular to the surface of the sidewall 10 is referred to as a circular pattern.

Also, as shown in FIG. 17, a band-shaped region 27 may be provided on the tire radial outer side of the decorative region 11, in which multiple ridges 26 extending in the tire radial direction are arranged at equal intervals in the tire circumferential direction. The multiple 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 part of the tire circumferential direction, or may be provided over the entire tire circumferential direction. The band-shaped region 27 is adjacent to the outside 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.

By providing such a band-like region 27, it is possible to suppress unevenness and bareness at the interface between the tread rubber 6 and the sidewall rubber 7. In addition, the black band-like region is formed by the light attenuation effect caused by providing the protruding stripes 26, making the decorative region 11 stand out.

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 (7)

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 the reference point,
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 having a center on the reference point on the inside of the spiral is inscribed in the circular pattern having a center on the reference point immediately outside of the circular pattern having a center on the reference point on the outside of the circular pattern. The pneumatic tire according to claim 1, wherein the linear distance between adjacent reference points on the spiral is greater on the outer side of the spiral. The pneumatic tire according to claim 1, wherein the linear distances between adjacent reference points on the spiral are equal. The pneumatic tire according to any one of claims 1 to 3, wherein when the linear distance between two adjacent reference points on the spiral is P, the radius of the circular pattern centered on the outer reference point of the two reference points on the spiral is a value obtained by adding P to the radius of the circular pattern centered on the inner reference point of the two reference points on the spiral. The pneumatic tire according to any one of claims 1 to 4, wherein the cross-sectional shape of the circular pattern includes a triangle, a trapezoid, a rectangle, or a semicircle. The pneumatic tire according to any one of claims 1 to 5, wherein the sidewall is provided with an area in which a plurality of ridges extending in the tire radial direction are arranged at equal intervals in the tire circumferential direction, the area having a dimension in the tire radial direction of 5 mm to 12 mm, radially outward of the decorative area in which the circular pattern is provided. The pneumatic tire according to any one of claims 1 to 6, wherein the circular pattern is a protrusion protruding from the tire surface.