JP7707769B2 - tire - Google Patents

Description

This disclosure relates to tires.

The following Patent Document 1 describes a tire in which micro-protrusions are arranged on the decorative portion. The micro-protrusions have recesses at the tops of the protrusions. Such recesses reduce the reflection of irradiated light, making the decorative portion appear darker. This is said to increase the contrast between the decorative portion and the adjacent non-decorative portion, improving visibility.

JP 2020-29209 A

In recent years, there has been a demand for improving the appearance of tires by making unevenness such as bulge dents and bare spots on the outer surface less noticeable.

This disclosure was devised in light of the above-mentioned circumstances, and aims to provide a tire with improved appearance performance.

The present disclosure is directed to a tire having a decorative portion on at least a portion of the tire's visible outer surface, the decorative portion having 2 to 10 microprotrusions arranged per 1 ^mm2 , the microprotrusions extending in a tapered manner toward the outside of the tire, and the microprotrusions including a first protrusion and a second protrusion having a larger taper angle than the first protrusion.

By adopting the above configuration, the tire disclosed herein improves appearance performance.

FIG. 1 is a partial perspective view showing one embodiment of a tire of the present disclosure. FIG. 2 is an enlarged view of the decorative portion of FIG. 1 . 4A is a cross-sectional view of a first projection, and FIG. 4B is a cross-sectional view of a second projection. FIG. 2 is an enlarged front view of the decorative portion of FIG. 1 . FIG. 13 is an enlarged front view of a decorative portion according to another embodiment. 13 is an enlarged front view of a decorative portion of yet another embodiment. FIG. FIG. 13 is an enlarged view of a decorative portion according to another embodiment. 8 is a plan view of the second protrusion of the embodiment shown in FIG. 7 as viewed from above. FIG. 9 is an end view of line AA in FIG. 8. FIG. 13 is an enlarged view of a decorative portion according to another embodiment. 11A is a cross-sectional view of the first projection shown in FIG. 10, and FIG. 11B is a cross-sectional view of the second projection shown in FIG. FIG. 11 is a cross-sectional view of a second projection according to another embodiment.

Hereinafter, one embodiment of the present disclosure will be described with reference to the drawings.
Fig. 1 is a perspective view showing one embodiment of a tire 1 according to the present disclosure. Fig. 1 shows a pneumatic tire 1 for passenger cars as a preferred embodiment. However, the present disclosure may also be adopted in pneumatic tires 1 for motorcycles and heavy load vehicles, and in tires 1 of other categories.

As shown in FIG. 1, the tire 1 of this embodiment has a visible outer surface 1a. The visible outer surface 1a is the surface that can be seen from the outside when the tire 1 is mounted on a rim (not shown). The outer surface 1a includes, for example, the outer surface 2a of the tread portion 2, the outer surface 3a of the sidewall portion 3, and the outer surface 4a of the bead portion 4. The outer surface 1a of this embodiment is formed in black with carbon black.

In this embodiment, the tire 1 has a decorative portion 10 on a portion of the outer surface 1a. In this embodiment, the decorative portion 10 is provided on the outer surface 3a of the sidewall portion 3. Note that the decorative portion 10 is not limited to being provided on the outer surface 3a of the sidewall portion 3, and may be provided, for example, on the outer surface 2a of the tread portion 2 or the outer surface 4a of the bead portion 4.

In this embodiment, the decorative portion 10 is formed in an arc shape centered on the tire rotation axis (not shown). The decorative portion 10 includes an outer edge 10e in the tire radial direction and an inner edge 10i in the tire radial direction that extend in the tire circumferential direction. A plurality of decorative portions 10 may be provided in the tire circumferential direction. However, the decorative portion 10 is not limited to this form.

In this embodiment, the decorative portion 10 has 2 to 10 micro-protrusions 11 arranged per 1 ^mm2 . The micro-protrusions 11 extend, for example, in a tapered shape toward the outside of the tire. Such micro-protrusions 11 effectively capture the light incident on the decorative portion and have a high light absorption effect, thereby increasing the blackness of the decorative portion. The number of micro-protrusions 11 is the number obtained by dividing the number of micro-protrusions 11 that are completely contained within a rectangular region with one side of 5 mm when the outer surface 1a is developed on a plane by 25.

2 is an enlarged view of the decorative portion. FIG. 3(a) is a cross-sectional view of the first protrusion, and FIG. 3(b) is a cross-sectional view of the second protrusion. As shown in FIG. 2 and FIG. 3, the small protrusion 11 includes the first protrusion 12 and the second protrusion 13 having a larger taper angle than the first protrusion 12. The first protrusion 12 has a high blackness because it absorbs incident light and reflects it toward the inside of the tire. The second protrusion 13 can reflect incident light toward the outside of the tire, causing unevenness in the blackness between the first protrusion 12 and the first protrusion 12. Therefore, in the tire 1 of this embodiment, a light-dark contrast is generated in the decorative portion 10, and therefore the tire has excellent appearance performance. In addition, the light-dark contrast makes bulge dents, etc., less noticeable even if they occur in the sidewall portion 3, thereby further improving the appearance performance.

If the taper angle α1 of the first protrusions 12 is small, the rubber may be easily chipped, and the appearance may deteriorate. If the taper angle α1 of the first protrusions 12 is large, the incident light may be easily reflected to the outside of the tire. For this reason, the taper angle α1 is preferably 10 degrees or more, more preferably 20 degrees or more, even more preferably 30 degrees or more, preferably 100 degrees or less, even more preferably 90 degrees or less, and even more preferably 80 degrees or less.

If the taper angle α2 of the second protrusions 13 is small, the contrast (difference between light and dark) with the first protrusions 12 may be small. If the taper angle α2 of the second protrusions 13 is large, the incident light may be excessively reflected outward from the tire, and the blackness of the decorative portion 10 may be reduced. For this reason, the taper angle α2 is preferably 30 degrees or more, more preferably 40 degrees or more, even more preferably 50 degrees or more, preferably 120 degrees or less, even more preferably 110 degrees or less, and even more preferably 100 degrees or less.

The difference (α2-α1) between the taper angle α1 of the first protrusion 12 and the taper angle α2 of the second protrusion 13 is preferably 10 to 90 degrees. This increases the degree of blackness and makes the contrast clearer. To effectively exert this effect, it is more preferable that the difference (α2-α1) is 30 degrees or more, and even more preferable that it is 60 degrees or less.

It is desirable that the projection height h1 of the first projection 12 is greater than the projection height h2 of the second projection 13. As a result, the incident light reflected by the second projection 13 to the outside of the tire strikes the first projection 12 and is absorbed, so that the blackness is further increased. If the projection height h1 of the first projection 12 is excessively greater than the projection height h2 of the second projection 13, the first projection 12 may be too conspicuous, and the appearance performance may be deteriorated. For this reason, the projection height h1 of the first projection 12 is desirably 1.4 times or more, more desirably 2.0 times or more, even more desirably 2.5 times or more, preferably 5.0 times or less, more desirably 4.5 times or less, and even more desirably 4.0 times or less. In order to effectively exert this effect, the protrusion height h1 of the first protrusion 12 is preferably 0.1 mm or more, more preferably 0.2 mm or more, even more preferably 0.3 mm or more, preferably 0.8 mm or less, even more preferably 0.7 mm or less, and even more preferably 0.6 mm or less.

In this embodiment, the small protrusion 11 includes a protrusion base 14 that extends taperedly toward the outside of the tire, and a protrusion apex 15 that is connected to the protrusion base 14 and extends toward the outside of the tire at a gentler slope than the protrusion base 14. In this embodiment, the protrusion base 14 includes an inclined surface 14a that is formed in a straight line in the longitudinal section of the small protrusion 11. The protrusion base 14 may include, for example, a surface that is formed in a convex arc toward the outside of the tire, or a surface that is formed in a concave arc toward the inside of the tire (not shown). In this specification, the taper angle α1 of the first protrusion 12 and the taper angle α2 of the second protrusion 13 are the average angles at the protrusion base 14. The protrusion apex 15 is a portion formed with a taper angle exceeding 120 degrees.

The protrusion bases 14 of both the first protrusion 12 and the second protrusion 13 are formed in a truncated cone shape. Such protrusion bases 14 reflect and absorb incident light in multiple directions to the outside of the tire. A truncated cone shape includes not only a truncated cone with a circular bottom, but also an elliptical truncated cone. Note that each protrusion base 14 is not limited to this shape, and may be, for example, a truncated pyramid.

The projection apex 15A of the first projection 12 is flat. Such a projection apex 15A reflects incident light to the outside of the tire. This further increases the non-uniformity of the blackness, improving the appearance performance. The projection apex 15A of the first projection 12 is a circular flat surface. The projection apex 15A may be formed as a flat surface overall. Alternatively, the projection apex 15A may include a flat surface and a curved peripheral surface surrounding the flat surface to smoothly connect the flat surface to the projection base 14.

The projection apex 15B of the second projection 13 is a hemisphere that protrudes outward from the tire. Such projection apex 15B can scatter incident light and illuminate the first projection 12. The incident light that illuminates the first projection 12 is absorbed by the first projection 12, increasing the blackness of the decorative part 10. This further improves the appearance performance. In this specification, a hemisphere includes not only a configuration in which the sphere is bisected by a plane passing through the center of the sphere, but also a configuration in which the sphere is bisected by a plane passing through a point other than the center of the sphere.

It is desirable that the maximum diameter d1 of the protrusion apex 15A of the first protrusion 12 is the same as the maximum diameter d2 of the protrusion apex 15B of the second protrusion 13. This reduces the difference in the amount of light reflected by the protrusion apex 15A of the first protrusion 12 and the protrusion apex 15B of the second protrusion 13, thereby maintaining a high light-dark contrast.

The maximum diameter d1 of the projection apex 15A of the first projection 12 and the maximum diameter d2 of the projection apex 15B of the second projection 13 are both preferably 0.05 mm or more, more preferably 0.1 mm or more, more preferably 0.4 mm or less, and even more preferably 0.3 mm or less. Since the maximum diameters d1 and d2 are 0.05 mm or more, the unevenness of the blackness caused by the reflected light of each projection apex 15 can be increased. Since the maximum diameters d1 and d2 are 0.4 mm or less, the blackness can be ensured.

It is desirable that the maximum diameter D1 of the first protrusion 12 is smaller than the maximum diameter D2 of the second protrusion 13. This makes the area of the protrusion base 14 of the second protrusion 13 relatively large, increasing the non-uniformity of the blackness. Each maximum diameter D1, D2 is formed at the position of each protrusion 12, 13 that is furthest inward in the tire.

If the maximum diameter D1 of the first protrusions 12 is excessively smaller than the maximum diameter D2 of the second protrusions 13, the degree of blackness may be reduced. Therefore, the ratio (D2/D1) of the maximum diameter D1 of the first protrusions 12 to the maximum diameter D2 of the second protrusions 13 is preferably 1.1 times or more, more preferably 1.2 times or more, more preferably 2.0 times or less, and even more preferably 1.7 times or less.

Figure 4 is an enlarged front view of the decorative part 10. As shown in Figure 4, the decorative part 10 of this embodiment includes a first protrusion group 12R in which the first protrusions 12 are arranged in a continuous manner. Such a first protrusion group 12R increases the blackness because light reflected by the first protrusions 12 is irradiated to and absorbed by the adjacent first protrusions 12.

In addition, in this embodiment, the decorative portion 10 includes a second projection group 13R in which the second projections 13 are arranged continuously. In this second projection group 13R, adjacent second projections 13 increase the non-uniformity of the blackness.

Furthermore, the decorative portion 10 has, for example, the first projection group 12R and the second projection group 13R arranged alternately. This enhances the above-mentioned effect, emphasizes the contrast between light and dark, and further enhances the effect of making bulge dents and the like less noticeable. In this embodiment, the first projection group 12R and the second projection group 13R are arranged alternately in the tire circumferential direction.

The angle θ1 of the arrangement direction of the first protrusion group 12R with respect to the tire radial direction is preferably 30 degrees or more, more preferably 35 degrees or more, even more preferably 40 degrees or more, preferably 60 degrees or less, even more preferably 55 degrees or less, and even more preferably 50 degrees or less. Since the angle θ1 of the first protrusion group 12R is 30 degrees or more and 60 degrees or less, the visibility of the decorative part 10 is improved and the appearance performance can be improved. From the same viewpoint, the angle θ2 of the arrangement direction of the second protrusion group 13R with respect to the tire radial direction is preferably 30 degrees or more, more preferably 35 degrees or more, even more preferably 40 degrees or more, preferably 60 degrees or less, even more preferably 55 degrees or less, and even more preferably 50 degrees or less. It is preferable that the angle θ1 of the first protrusion group 12R and the angle θ2 of the second protrusion group 13R are the same. The angle θ1 of the first projection group 12R and the angle θ2 of the second projection group 13R are the angles at the intermediate position 10c in the tire radial direction between the outer edge 10e and the inner edge 10i of the decorative part 10.

In this embodiment, the total number of first protrusions 12 is greater than the total number of second protrusions 13. This allows the first protrusions 12 to have a significant effect in improving the blackness. If the total number of first protrusions 12 is excessively greater than the total number of second protrusions 13, the non-uniformity of the blackness may decrease. For this reason, the total number of first protrusions 12 is preferably 1.2 times or more than the number of second protrusions 13, more preferably 1.4 times or more, even more preferably 1.6 times or more, preferably 2.5 times or less, even more preferably 2.2 times or less, and even more preferably 2.0 times or less.

As shown in FIG. 2, the ratio (p1/D1) of the arrangement pitch p1 of the first protrusions 12 to the maximum diameter D1 (shown in FIG. 3) of the first protrusions 12 is preferably 1.05 or more, more preferably 1.15 or more, and more preferably 1.40 or less, and even more preferably 1.30 or less.

The ratio (p2/D2) of the arrangement pitch p2 of the second protrusions 13 to the maximum diameter D2 of the second protrusions 13 is preferably greater than the ratio (p1/D1) of the first protrusions 12. This provides a good balance between the effect of increasing the blackness and the effect of exhibiting non-uniformity in the blackness, making bulge dents and the like even less noticeable. From this perspective, the ratio (p2/D2) of the second protrusions 13 is preferably 1.35 or more, more preferably 1.45 or more, more preferably 1.65 or less, and even more preferably 1.55 or less.

The arrangement pitch P of the first projection group 12R and the adjacent second projection group 13R is preferably 1.6 times or more, more preferably 1.7 times or more, more preferably 2.0 times or less, and even more preferably 1.9 times or less, of the maximum diameter D1 of the first projections 12. Since the arrangement pitch P is 1.6 times or more of the maximum diameter D1 of the first projections, the unevenness of light and dark due to the projection apexes 15A, 15B of each projection 12, 13 is clearly visible, and contrast is emphasized. Since the arrangement pitch P is 2.0 times or less of the maximum diameter D1 of the first projections, the light reflected by the second projections 13 is effectively absorbed by the first projections 12.

Figure 5 is an enlarged view of the decorative part of another embodiment. Components that are the same as those of this embodiment are given the same reference numerals, and detailed description thereof may be omitted. As shown in Figure 5, in this embodiment, the decorative part 10 is formed so that multiple second protrusions 13 surround multiple first protrusions 12. The decorative part 10 is formed, for example, so that six second protrusions 13 surround three first protrusions 12.

Figure 6 is an enlarged view of the decorative part of yet another embodiment. Components that are the same as those of this embodiment are given the same reference numerals, and detailed description thereof may be omitted. As shown in Figure 6, in this embodiment, the decorative part 10 is formed so that multiple first protrusions 12 surround one second protrusion 13. The decorative part 10 is formed, for example, so that twelve first protrusions 12 surround one second protrusion 13.

Below, a further embodiment of the present disclosure is described. In each of the figures given below, components that are the same as those in the above-mentioned embodiment may be given the same reference numerals and detailed description thereof may be omitted. The above points can be applied to the components whose description is omitted.

Figure 7 is an enlarged view of the decorative portion 10 of another embodiment. As shown in Figure 7, in this embodiment, the first protrusion 12 is substantially the same as that described above. Meanwhile, the second protrusion 13 has a different configuration from that described above.

8 shows a plan view of the second protrusion 13 of the embodiment shown in FIG. 7 when viewed from above. FIG. 9 shows an end view of line A-A in FIG. 8. As shown in FIGS. 8 and 9, the second protrusion 13 of this embodiment includes a protrusion base 14 that extends taperedly toward the outside of the tire. The protrusion base 14 also includes an inclined surface 14a that defines the taper angle, and at least one protrusion 20 that protrudes from the inclined surface 14a. The second protrusion 13 including such a protrusion 20 can scatter incident light in a more complex manner, and can also be expected to absorb the scattered light. Therefore, the blackness of the second protrusion 13 is increased, and the light-dark contrast with the first protrusion 12 can be further increased. In order to make the configuration easier to understand, the protrusion 20 in FIG. 8 is dotted.

As shown in FIG. 8, the second protrusion 13 in this embodiment includes multiple raised portions 20. The number of raised portions 20 included in one second protrusion 13 is, for example, 2 to 6, and preferably 2 to 4. In a more desirable embodiment, the bottom edge 22 of the second protrusion 13 is configured to be circular when viewed from above, and multiple raised portions 20 are disposed at equal intervals in the circumferential direction of the bottom edge 22. This further improves the blackness of the second protrusion 13.

For example, the raised portion 20 preferably extends long along the generatrix 17 of the inclined surface 14a (shown by a two-dot chain line in FIG. 8 for ease of understanding). That is, the length L1 of the raised portion 20 in the generatrix direction is greater than the length L2 of the raised portion 20 in the circumferential direction. Specifically, the length L1 is 1.5 to 3.5 times the length L2. In a more preferable embodiment, the second projection 13 includes a projection base 14 including a tapered inclined surface 14a and a hemispherical projection apex 15 that is convex toward the outside of the tire, and the raised portion 20 extends from the boundary 16 between the projection base 14 and the projection apex 15 (shown by a two-dot chain line in FIG. 8 for ease of understanding) to the bottom edge 22 of the second projection 13. This further increases the contrast between the light and dark of the first projection 12 and the second projection 13, further improving the appearance performance.

As shown in FIG. 9, in a longitudinal section of the second projection 13 passing through the raised portion 20, the outer surface 20s of the raised portion 20 is desirably curved, for example, in a circular arc shape that is convex toward the outside of the tire. The radius of curvature r1 of the outer surface 20s of the raised portion 20 is desirably, for example, 80% to 120% of the height h3 from the bottom edge 22 of the second projection 13 to the boundary 16 between the projection base 14 and the projection top 15. This makes it possible to achieve the above-mentioned effects while suppressing molding defects of the raised portion 20 during vulcanization molding.

From a similar perspective, it is desirable that the maximum height h4 from the inclined surface 14a to the outer surface of the raised portion 20 in the longitudinal section be 20% to 30% of the projection height h2 of the second projection 13.

Figure 10 is an enlarged view of a decorative portion 10 of yet another embodiment. As shown in Figure 10, the small protrusions 11 of this embodiment include an annular bottom edge 22, a bottom area which is the area of the region surrounded by the bottom edge 22 in a top view, a vertex 24 located at the farthest position from the bottom edge 22, and a protrusion height from the bottom edge 22 to the vertex 24. The small protrusions 11 also include a first protrusion 12 and a second protrusion 13.

Figure 11(a) shows a cross-sectional view of the first protrusion 12 of the embodiment shown in Figure 10. Figure 11(b) shows a cross-sectional view of the second protrusion 13 of the embodiment shown in Figure 10. As shown in Figures 11(a) and (b), in this embodiment, the bottom area of the second protrusion 13 is larger than the bottom area of the first protrusion 12. Also, the protrusion height h2 of the second protrusion 13 is smaller than the protrusion height h1 of the first protrusion 12. The decorative part 10 including such first protrusion 12 and second protrusion 13 has excellent appearance performance because a light and dark contrast is generated.

From the viewpoint of suppressing molding defects during vulcanization while increasing the contrast, the protrusion height h1 of the first protrusions 12 is preferably 1.4 times or more, more preferably 2.0 times or more, even more preferably 2.5 times or more, preferably 5.0 times or less, even more preferably 4.5 times or less, and even more preferably 4.0 times or less, the protrusion height h2 of the second protrusions 13. In addition, the bottom area of the second protrusions 13 is preferably 1.1 times or more, more preferably 1.3 times or more, and preferably 2.5 times or less, and more preferably 2.2 times or less, the bottom area of the first protrusions 12.

In this embodiment, the first protrusion 12 is substantially the same as that described above. Meanwhile, the second protrusion 13 has a different configuration than that described above.

As shown in FIG. 10, the second protrusion 13 in this embodiment includes a protrusion base 14 that extends from the bottom edge 22 outward from the tire and has a dome-shaped outer surface, and a protrusion apex 15 that protrudes further from the protrusion base 14. Such a second protrusion 13 can further increase the light-dark contrast with the first protrusion 12, further improving the appearance performance. Note that the dome-shaped outer surface means a surface that is curved and convex toward the outside of the tire.

As shown in FIG. 11(b), the height h3 of the protrusion base 14 of the second protrusion 13 is preferably, for example, 65% to 85% of the protrusion height h2 of the second protrusion 13. In addition, the outer surface of the protrusion base 14 of the second protrusion 13 in this embodiment is curved in a convex arc shape toward the outside of the tire in a vertical cross section passing through the apex of the second protrusion 13. In addition, the radius of curvature r2 of the outer surface of the protrusion base 14 in the vertical cross section is, for example, 100% to 150% of the height h3 of the protrusion base 14, and is preferably 1.0 mm or less. Such second protrusions 13 can increase the blackness while suppressing molding defects during vulcanization.

The projection apex 15 of the second projection 13 desirably has, for example, a dome-shaped outer surface that protrudes further from the projection base 14. As a result, the outer surface 15a of the projection apex 15 of the second projection 13 is curved in a convex arc shape toward the outside of the tire in the longitudinal section. In addition, the radius of curvature r3 of the outer surface 15a of the projection apex 15 of the second projection 13 is smaller than the radius of curvature r2 of the projection base 14. Specifically, the radius of curvature r3 is 30% to 60% of the radius of curvature r2. In addition, the height h5 of the projection apex 15 is, for example, 20% to 30% of the projection height h2 of the second projection 13. This further improves the blackness of the second projection 13.

The configuration of the second protrusion 13 is not limited to the above embodiment. For example, the second protrusion 13 may have a dome-shaped protrusion base 14 and a protrusion apex 15 that is substantially planar (not shown).

Figure 12 shows a cross-sectional view of the second protrusion 13 in yet another embodiment. As shown in Figure 12, the second protrusion 13 may be configured in a dome shape as a whole. This makes it possible to suppress molding defects during vulcanization while still achieving the above-mentioned effects.

The decorative portion 10 of the embodiment shown in Fig. 7 and Fig. 10 each includes a first projection group 12R in which the first projections 12 are arranged, and a second projection group 13R in which the second projections 13 are continuously arranged. In addition, the first projection group 12R and the second projection group 13R are arranged alternately in the tire circumferential direction, for example.

The first protrusions 12 and second protrusions 13 shown in FIG. 7 or FIG. 10 can be arranged in various ways, and may be arranged in the ways shown in FIG. 5 to 6, for example. That is, in the decorative part 10 including the first protrusions 12 and the second protrusions 13 shown in FIG. 7 or FIG. 10, multiple second protrusions 13 may be formed to surround multiple first protrusions 12, as shown in FIG. 5. Also, in the decorative part 10 including the first protrusions 12 and the second protrusions 13 shown in FIG. 7 or FIG. 10, multiple first protrusions 12 may be formed to surround one second protrusion 13, as shown in FIG. 6. With such a decorative part 10, further improvement in appearance performance can be expected.

The above describes in detail a particularly preferred embodiment of the present disclosure, but the present disclosure is not limited to the illustrated embodiment and can be modified and implemented in various ways.

In order to confirm the effect of the present disclosure, pneumatic tires having a decorative portion on the outer surface of the sidewall portion as shown in Fig. 1 and Fig. 2 were prototyped. Then, the appearance performance of each prototype tire was tested. Specifications other than those listed in Table 1 are substantially the same for both the comparative example and the example.
Maximum diameter D1 of first protrusion: 0.4 mm
Height of first projection h1: 0.4 mm
Arrangement pitch of first projections p1: 0.5 mm
Arrangement pitch of second projections p2: 0.7 mm
Arrangement pitch P between the first projection group and the second projection group: 0.9 mm
Array direction angles θ1, θ2: 45 degrees

<Appearance performance>
An inspector visually inspected the prototype tires from the side at a distance of 1 m, and evaluated the appearance performance based on the degree to which bulge dents and the like were less noticeable due to the contrast of the decorative portion. The results are shown on a scale of 10, with Example 1 being given a score of 10. The higher the score, the less noticeable the bulge dents and the better the appearance performance.
The results of the tests are shown in Table 1.

It can be seen that the tires of the examples have superior appearance performance compared to the tires of the comparative examples.

A pneumatic tire having a decorative portion as shown in FIG. 7 or FIG. 10 on the outer surface of the sidewall portion was prototyped and tested for the above-mentioned appearance performance.
The results of the tests are shown in Table 2.

As shown in Table 2, it was confirmed that the embodiments shown in Figures 7 and 10 also have excellent appearance performance, similar to the embodiment shown in Figure 2.

[Additional Notes]
The present disclosure includes the following aspects.

[Disclosure 1]
A tire,
The tire has a decorative portion on at least a portion of a visible outer surface thereof,
The decorative portion has 2 to 10 microprojections arranged per 1 ^mm2 ,
The small protrusions extend outwardly of the tire in a tapered shape,
The small protrusions include a first protrusion and a second protrusion having a larger taper angle than the first protrusion.
tire.
[Disclosure 2]
The tire described in Disclosure 1, wherein a projection height of the first projection is greater than a projection height of the second projection.
[Disclosure 3]
The tire according to Disclosure 1 or 2, wherein a difference between the taper angle of the first projection and the taper angle of the second projection is 10 to 90 degrees.
[Disclosure 4]
The tire according to any one of Disclosures 1 to 3, wherein the decorative portion includes a first projection group in which the first projections are continuously arranged.
[Disclosure 5]
The tire according to Disclosure 4, wherein an angle of the arrangement direction of the first projection group with respect to the tire radial direction is 30 to 60 degrees.
[Disclosure 6]
The tire according to any one of the first to fifth disclosures, wherein the decorative portion includes a second projection group in which the second projections are continuously arranged.
[Disclosure 7]
The tire according to any one of Disclosures 1 to 6, wherein a projection apex of the first projection is flat.
[Disclosure 8]
The tire according to any one of Disclosures 1 to 7, wherein a projection apex of the second projection is hemispherical and convex toward an outside of the tire.
[Disclosure 9]
The tire according to any one of Disclosures 1 to 8, wherein the total number of the primary projections is 1.2 to 2.5 times the total number of the secondary projections.
[Disclosure 10]
The small projections include projection bases that extend tapered outwardly of the tire,
The tire according to any one of disclosures 1 to 9, wherein the projection base of the second projection includes an inclined surface that defines the taper angle, and at least one raised portion raised from the inclined surface.
[Disclosure 11]
The tire of disclosure 10, wherein the second projection includes a plurality of the raised portions.
[Disclosure 12]
12. The tire according to disclosure 10 or 11, wherein the raised portion extends elongately along the generating line of the inclined surface.
[Disclosure 13]
A tire,
The tire has a decorative portion on at least a portion of a visible outer surface thereof,
The decorative portion has 2 to 10 microprojections arranged per 1 ^mm2 ,
The small protrusion includes an annular bottom edge, a bottom area which is an area of a region surrounded by the bottom edge in a top view, a vertex located at a position farthest from the bottom edge, and a protrusion height from the bottom edge to the vertex,
the microprojections include first projections and second projections;
The bottom area of the second protrusion is larger than the bottom area of the first protrusion,
The projection height of the second projection is smaller than the projection height of the first projection.
tire.
[Disclosure 14]
The first projection extends outwardly of the tire in a tapered shape,
The tire of disclosure 13, wherein the second projection includes a projection base portion extending from the bottom edge toward the outside of the tire and having a dome-shaped outer surface, and a projection apex portion further protruding from the projection base portion.
[Disclosure 15]
The first projection extends outwardly of the tire in a tapered shape,
The tire of disclosure 13, wherein the second projection is configured generally in a dome shape.
[Disclosure 16]
The tire according to any one of disclosures 13 to 15, wherein the decorative portion includes a first projection group in which the first projections are continuously arranged, and a second projection group in which the second projections are continuously arranged.
[Disclosure 17]
The tire according to disclosure 16, wherein the first projection groups and the second projection groups are arranged alternately in the tire circumferential direction.
[Disclosure 18]
The tire according to any one of disclosures 13 to 15, wherein the decorative portion is formed such that a plurality of the first projections surround one of the second projections.
[Disclosure 19]
19. The tire according to any one of claims 13 to 18, wherein the bottom area of the secondary projections is 1.1 to 2.5 times the bottom area of the primary projections.
[Disclosure 20]
20. The tire according to any one of claims 13 to 19, wherein the projection height of the first projections is 1.4 to 5.0 times or less the projection height of the second projections.

Reference Signs List 1: Tire 1a: Outer surface 10: Decorative portion 11: Small protrusion 12: First protrusion 13: Second protrusion

Claims (16)

A tire,
The tire has a decorative portion on at least a portion of a visible outer surface thereof,
The decorative portion has 2 to 10 microprojections arranged per 1 ^mm2 ,
The small protrusions extend outwardly of the tire in a tapered shape,
The small protrusions include a first protrusion and a second protrusion having a larger taper angle than the first protrusion,
a difference between the taper angle of the first projection and the taper angle of the second projection is 10 to 90 degrees;
tire. A tire,
The tire has a decorative portion on at least a portion of a visible outer surface thereof,
The decorative portion is 1 mm ² 2 to 10 microprojections are arranged per
The small protrusions extend outwardly of the tire in a tapered shape,
The small protrusions include a first protrusion and a second protrusion having a larger taper angle than the first protrusion,
the decorative portion includes a first projection group in which the first projections are continuously arranged,
the angle of the arrangement direction of the first projection group with respect to the tire radial direction is 30 to 60 degrees;
tire. A tire,
The tire has a decorative portion on at least a portion of a visible outer surface thereof,
The decorative portion is 1 mm ² 2 to 10 microprojections are arranged per
The small protrusions extend outwardly of the tire in a tapered shape,
The small protrusions include a first protrusion and a second protrusion having a larger taper angle than the first protrusion,
the total number of the first protrusions is 1.2 to 2.5 times the total number of the second protrusions;
tire. A tire,
The tire has a decorative portion on at least a portion of a visible outer surface thereof,
The decorative portion is 1 mm ² 2 to 10 microprojections are arranged per
The small protrusions extend outwardly of the tire in a tapered shape,
The small protrusions include a first protrusion and a second protrusion having a larger taper angle than the first protrusion,
The small projections include projection bases that extend tapered outwardly of the tire,
The projection base of the second projection includes an inclined surface that defines the taper angle, and at least one protruding portion that protrudes from the inclined surface.
tire. The tire of claim 4 , wherein the second projection includes a plurality of the raised portions . 6. The tire according to claim 4, wherein the raised portion extends elongately along a generating line of the inclined surface. The tire according to claim 1 , wherein a projection height of the first projections is greater than a projection height of the second projections . The tire according to claim 1 , wherein the decorative portion includes a second projection group in which the second projections are continuously arranged . The tire according to claim 1 , wherein a projection apex of the primary projection is flat . The tire according to claim 1 , wherein a projection apex of the second projection is hemispherical and convex outwardly of the tire . A tire,
The tire has a decorative portion on at least a portion of a visible outer surface thereof,
The decorative portion is 1 mm ² 2 to 10 microprojections are arranged per
The small protrusion includes an annular bottom edge, a bottom area which is an area of a region surrounded by the bottom edge in a top view, a vertex located at a position farthest from the bottom edge, and a protrusion height from the bottom edge to the vertex,
the microprojections include first projections and second projections;
The bottom area of the second protrusion is larger than the bottom area of the first protrusion,
The projection height of the second projection is smaller than the projection height of the first projection,
the decorative portion includes a first projection group in which the first projections are continuously arranged, and a second projection group in which the second projections are continuously arranged,
The first projection group and the second projection group are arranged alternately in the tire circumferential direction.
tire. A tire,
The tire has a decorative portion on at least a portion of a visible outer surface thereof,
The decorative portion is 1 mm ² 2 to 10 microprojections are arranged per
The small protrusion includes an annular bottom edge, a bottom area which is an area of a region surrounded by the bottom edge in a top view, a vertex located at a position farthest from the bottom edge, and a protrusion height from the bottom edge to the vertex,
the microprojections include first projections and second projections;
The bottom area of the second protrusion is larger than the bottom area of the first protrusion,
The projection height of the second projection is smaller than the projection height of the first projection,
The decorative portion is formed such that a plurality of the first protrusions surround one of the second protrusions.
tire. A tire,
The tire has a decorative portion on at least a portion of a visible outer surface thereof,
The decorative portion is 1 mm ² 2 to 10 microprojections are arranged per
The small protrusion includes an annular bottom edge, a bottom area which is an area of a region surrounded by the bottom edge in a top view, a vertex located at a position farthest from the bottom edge, and a protrusion height from the bottom edge to the vertex,
the microprojections include first projections and second projections;
The bottom area of the second protrusion is larger than the bottom area of the first protrusion,
The projection height of the second projection is smaller than the projection height of the first projection,
The bottom area of the second projection is 1.1 to 2.5 times the bottom area of the first projection.
tire. A tire,
The tire has a decorative portion on at least a portion of a visible outer surface thereof,
The decorative portion is 1 mm ² 2 to 10 microprojections are arranged per
The small protrusion includes an annular bottom edge, a bottom area which is an area of a region surrounded by the bottom edge in a top view, a vertex located at a position farthest from the bottom edge, and a protrusion height from the bottom edge to the vertex,
the microprojections include first projections and second projections;
The bottom area of the second protrusion is larger than the bottom area of the first protrusion,
The projection height of the second projection is smaller than the projection height of the first projection,
The projection height of the first projections is 1.4 to 5.0 times the projection height of the second projections.
tire. The first projection extends outwardly of the tire in a tapered shape,
15. The tire according to claim 11, wherein the second projection includes a projection base portion extending from the bottom edge toward the outside of the tire and having a dome-shaped outer surface, and a projection apex portion further protruding from the projection base portion. The first projection extends outwardly of the tire in a tapered shape ,
The tire according to claim 11 , wherein the second projection is configured in an overall dome shape.