Tire

Abstract

To provide a tire capable of increasing the blackness of a decorative part, and suppressing the lowering of the blackness even when continuous production is performed.SOLUTION: A tire has a decorative part 10 on at least a portion of a visually recognizable outer surface of a tire. Two to 10 minute projections 11 per 1 mm2 are arranged on the decorative part 10. In the minute projections 11, recesses 15 are disposed on projection tops 13. Inside minute projections 19 are arranged inside the recesses 15.SELECTED DRAWING: Figure 2

Description

Technical Field

[0001] The present disclosure relates to a tire.

Background Art

[0002] Patent Document 1 below describes a tire in which an annular decorative pattern is formed on a sidewall portion. The decorative pattern is formed with a group of ridges in which ridges having the same cross-sectional shape are arranged continuously in the tire circumferential direction as a pattern unit. The ridge is configured in a substantially trapezoidal shape having an outer surface portion located on the outer side of the tire and a pair of inclined side surface portions extending from the outer surface portion toward the inner side of the tire. Such a decorative pattern is said to be able to strongly represent the original black color of the tire.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] In recent years, in order to enhance the commercial value of tires, there has been a demand to suppress the reflection of light in a specific area and enhance the blackness degree (the ability to be recognized as black) of the area. Further, when such tires are continuously produced, for example, between a plurality and several hundreds of tires, it is required to suppress a decrease in the blackness degree of the area in the several hundreds-th tire.

[0005] The present disclosure has been devised in view of the above actual situation, and an object thereof is to provide a tire capable of enhancing the blackness degree of a decorative portion and suppressing a decrease in the blackness degree even in the case of continuous production.

Means for Solving the Problems

[0006] The present disclosure relates to a tire having a decorative portion on at least a part of the visible outer surface of the tire, and the decorative portion has 2 to 10 minute protrusions per 1 mm 2 and at least one of the minute protrusions is provided with a recess at the top of the protrusion, and inner minute protrusions are arranged inside the recess.

Advantages of the Invention

[0007] By adopting the above configuration, the tire of the present disclosure can enhance the blackness degree of the decorative portion and suppress the decrease in the blackness degree even during continuous production.

Brief Description of the Drawings

[0008]

Figure 1

Figure 2

Figure 3

Figure 4

Figure 5

Figure 6

Figure 7

Figure 8

Figure 9

Figure 10

Modes for Carrying Out the Invention

[0009] Hereinafter, an embodiment of the present disclosure will be described with reference to the drawings. FIG. 1 is a partial perspective view showing an embodiment of the tire 1 of the present disclosure. In FIG. 1, as a preferred embodiment, a pneumatic tire 1 for a passenger car is shown. However, the present disclosure may be applied to, for example, a pneumatic tire 1 for a motorcycle or a heavy load, or a tire 1 of another category.

[0010] As shown in FIG. 1, the tire 1 of the present embodiment has a visible outer surface 1a. The visible outer surface 1a is a surface that can be visually observed from the outside when the tire 1 is incorporated into 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.

[0011] In the present embodiment, the tire 1 has a decorative portion 10 on a part of the outer surface 1a. The decorative portion 10 of the present embodiment is provided on the outer surface 3a of the sidewall portion 3. Note that the decorative portion 10 may be provided on, for example, the outer surface 2a of the tread portion 2 or the outer surface 4a of the bead portion 4.

[0012] FIG. 2 is an enlarged view of the decorative portion 10. As shown in FIG. 2, in the decorative portion 10 of the present embodiment, 2 to 10 minute protrusions 11 are arranged per 1 mm. 2 The minute protrusions 11, for example, change the angle of the light irradiated to the decorative portion 10 and reflect and attenuate it, so that a high blackness degree is achieved. Note that the number of the minute protrusions 11 per 1 mm 2 is obtained, for example, by dividing the number of the minute protrusions 11 having a complete shape included in a region of a square having a side of 5 mm in the development when the outer surface 1a is developed into a plane by 25. Also, although not particularly limited, it is desirable that the arrangement pitch P of such minute protrusions 11 is 0.6 to 1.0 mm.

[0013] At least one minute protrusion 11 is provided with a recess 15 at the protrusion top 13. Such a recess 15 reduces the reflection of the irradiated light. In the present embodiment, the recess 15 is provided in each of the minute protrusions 11.

[0014] Inside the recess 15, inner micro-protrusions 19 are arranged. The inner micro-protrusions 19, for example, make the bottom side (inner side) of the recess 15 less visible to suppress reflection and further enhance the blackness degree. Also, the inner micro-protrusions 19 attenuate the light irradiated into the recess 15 by reflection and further reduce the reflection of light from inside the recess 15.

[0015] As shown in FIG. 1, the decorative part 10 of the present embodiment is formed in an arc shape extending in the tire circumferential direction around a tire rotation axis (not shown). The decorative parts 10 may be provided at intervals in the tire circumferential direction or may be provided continuously in the tire circumferential direction. Also, various shapes are adopted for the decorative part 10.

[0016] As shown in FIG. 2, in the present embodiment, the decorative part 10 includes micro-protrusions 11 and a planar protrusion formation surface 12 that connects between the micro-protrusions 11 and a plurality of adjacent micro-protrusions 11 adjacent thereto. Note that the decorative part 10 is not limited to such a mode, and for example, it may further include unevenness for logo display (not shown).

[0017] The micro-protrusions 11 include, for example, a protrusion top 13 and an inclined surface 14 that extends from the protrusion top 13 to the protrusion formation surface 12 with a steep slope. In the present embodiment, the micro-protrusions 11 are formed in a frustum of a cone shape that extends in a tapered shape toward the outside of the tire. In other words, the contour shape of the inclined surface 14 is formed in a circular shape. Such micro-protrusions 11 reflect light in multiple directions on the inclined surface 14 to attenuate it. Note that the contour shape of the inclined surface 14 may be, for example, an elliptical shape. In this specification, "circular shape" and "elliptical shape" include not only a circle and an ellipse but also those including deformation due to accuracy errors during tire manufacturing.

[0018] In this embodiment, the protruding top portion 13 is formed in a planar shape. Such a protruding top portion 13 emphasizes the contrast in light and shade with the concave portion 15 and enhances the darkness of the concave portion 15. Note that the protruding top portion 13 may be formed, for example, in a hemispherical shape convex toward the outside of the tire. Such a protruding top portion 13 reflects light in multiple directions to ensure the blackness degree of the protruding top portion 13.

[0019] The protruding formation surface 12 is formed, for example, in a rough surface shape. Such a protruding formation surface 12 helps to increase the blackness degree of the decorative portion 10. The ten-point average roughness (Rz) of the protruding formation surface 12 is desirably 0.01 to 0.05 mm. The ten-point average roughness (Rz) is measured in accordance with JIS B0601 (1994).

[0020] FIG. 3 is a perspective view of the micro-protrusion 11. As shown in FIG. 3, for the protrusion height H1 of the micro-protrusion 11, for example, it is desirably 0.15 mm or more, more desirably 0.20 mm or more, desirably 0.60 mm or less, and more desirably 0.50 mm or less. Also, for the maximum diameter D1 of the micro-protrusion 11, for example, it is desirably 0.30 mm or more, more desirably 0.40 mm or more, desirably 0.70 mm or less, and more desirably 0.60 mm or less. Further, for the diameter (the maximum diameter of the protruding top portion 13) D2 on the protruding top portion 13 side of the micro-protrusion 11, it is desirably 65% or more of the maximum diameter D1, more desirably 70% or more, desirably 85% or less, and more desirably 80% or less.

[0021] The width W1 of the protruding top portion 13 is desirably 0.2 mm or less. Thereby, the reflected light of the protruding top portion 13 becomes smaller, and the blackness degree of the decorative portion 10 is further enhanced.

[0022] The concave portion 15 includes a wall surface portion 16 extending from the protruding top portion 13 toward the base (protrusion base) side of the micro-protrusion 11, and a bottom portion 17 connected to the wall surface portion 16 on the protrusion base side.

[0023] The opening contour 16a of the wall surface portion 16 is, for example, circular or elliptical. Such a wall surface portion 16 reflects the light irradiated thereon in multiple directions and attenuates it. The opening contour 16a is circular in this embodiment. Also, the opening contour 16a is desirably, for example, of the same shape (including similar shapes) in the depth direction of the recess 15.

[0024] The area surrounded by the opening contour 16a is the same in the depth direction of the recess 15 in this embodiment. In other words, the recess 15 of this embodiment is formed in a cylindrical shape when there are no inner micro-protrusions 19. Such a recess 15 reduces the light that the wall surface portion 16 reflects outward of the tire, achieving a high blackness degree. Note that the area surrounded by the opening contour 16a may become smaller toward the bottom portion 17 side of the recess 15 (not shown). Such a recess 15 has a smaller area of the bottom portion 17, reducing the light reflected thereon.

[0025] The depth H2 of the recess 15 is desirably, for example, 15% or more of the protrusion height H1 of the micro-protrusions 11. Thereby, the light irradiated into the recess 15 is effectively attenuated by the wall surface portion 16, so that the blackness degree of the decorative portion 10 can be enhanced. From such a viewpoint, the depth H2 of the recess 15 is desirably 30% or more of the protrusion height H1 of the micro-protrusions 11, more desirably 60% or more, and even more desirably 80% or more. Although not particularly limited, the depth H2 of the recess 15 is desirably 100% or less of the protrusion height H1 of the micro-protrusions 11.

[0026] The diameter D4 at the protruding top portion 13 of the recess 15 is desirably 0.20 mm or more, more desirably 0.30 mm or more, desirably 0.60 mm or less, and more desirably 0.50 mm or less. Also, the diameter D3 at the bottom portion 17 of the recess 15 is desirably equal to or less than the diameter D4 at the protruding top portion 13 of the recess 15. In this embodiment, the diameter D3 is the same as the diameter D4.

[0027] The recess 15 includes an inner recess 15A arranged at the same position as the inner minute protrusion 19 in the protrusion height direction. In the present embodiment, the inner recess 15A is formed in an annular shape. Further, the recess 15 includes an outer recess 15B adjacent to the outer side of the inner recess 15A in the protrusion height direction. The outer recess 15B is formed, for example, in a columnar shape.

[0028] In the present embodiment, the inner minute protrusion 19 has an inner top portion 20 located on the outer side in the protrusion height direction and a side surface portion 21 extending from the inner top portion 20 toward the bottom portion 17. In the present embodiment, the inner top portion 20 is formed in a planar shape. Note that the inner top portion 20 may be formed, for example, in a hemispherical shape convex toward the outer side of the tire. The side surface portion 21 of the present embodiment is formed in a tapered shape from the bottom portion 17 toward the inner top portion 20. In a longitudinal cross section passing through the center of the inner top portion 20, the side surface portion 21 extends linearly from the inner top portion 20 toward the bottom portion 17, and in the present embodiment, extends linearly from the inner top portion 20 to the bottom portion 17.

[0029] For example, the inner minute protrusion 19 extends from the bottom portion 17 toward the protrusion top portion 13 side without contacting the wall surface portion 16. Such an inner minute protrusion 19 serves to direct the reflected light from the side surface portion 21 onto the wall surface portion 16 to attenuate it and enhance the blackness degree of the decorative portion 10.

[0030] The cross section of the inner minute protrusion 19 is circular or elliptical. In the present embodiment, the cross section of the inner minute protrusion 19 is circular. When the cross section of the minute protrusion 11 is elliptical, it is desirable that the cross section of the inner minute protrusion 19 be elliptical.

[0031] The cross-sectional area of the inner minute protrusion 19 becomes smaller toward the outer side in the protrusion height direction. Such an inner minute protrusion 19 can reduce the area of the inner top portion 20 of the inner minute protrusion 19, so that the reflected light from the inner top portion 20 can be reduced. Note that the cross-sectional area of the inner minute protrusion 19 may be the same in the protrusion height direction. Such an inner minute protrusion 19 enhances the blackness degree of the side surface portion 21.

[0032] The maximum diameter D6 of the inner micro-protrusion 19 on the side closest to the protrusion top 13 is desirably 0.10 mm or more, more desirably 0.20 mm or more, desirably 0.50 mm or less, and more desirably 0.40 mm or less. Also, the maximum diameter D5 of the inner micro-protrusion 19 on the side of the protrusion base is desirably larger than the maximum diameter D6 of the inner micro-protrusion 19 on the side closest to the protrusion top 13.

[0033] The shortest distance W2 between the outer end 19e of the inner micro-protrusion 19 on the side closest to the bottom 17 and the wall surface portion 16 is desirably 0.1 mm or less. Thereby, the area of the bottom 17 becomes small, and the light reflected from the bottom 17 to the outside of the protrusion top 13 is reduced, so that the blackness degree increases.

[0034] In order to ensure the blackness degree of the protrusion top 13, the protrusion height H3 of the inner micro-protrusion 19 is desirably 100% or less of the depth H2, more desirably smaller than the depth H2 of the recess 15, further desirably 85% or less of the depth H2 of the recess 15, and even more desirably 70% or less.

[0035] If the protrusion height H3 of the inner micro-protrusion 19 is excessively small, the blackness degree on the side of the bottom 17 of the recess 15 becomes small. Therefore, the protrusion height H3 of the inner micro-protrusion 19 is desirably 30% or more of the depth H2 of the recess 15, and more desirably 40% or more.

[0036] When such a decorative portion 10 has its micro-protrusions 11 densely arranged with a uniform size, it appears darker, so that the contrast becomes clear. On the other hand, when the size and arrangement of the micro-protrusions 11 are random, there is an advantage that damaged portions such as cracks and chips are less noticeable compared to the case where they are densely arranged as described above.

[0037] The decorative portion 10 is formed of the same rubber as, for example, the rubber member of the tire 1 that forms the outer surface 3a. As a method for forming such a decorative portion 10, for example, uneven portions (not shown) of an inverted pattern of the minute projections 11 may be provided on the inner surface of a vulcanization mold for tire molding, and the decorative portion 10 may be formed together with the vulcanization molding of the tire 1. Further, as a method for forming such a decorative portion 10, for example, the decorative portion 10 may be provided on the tire 1 after vulcanization molding by well-known machining or laser processing. It is desirable to use, for example, a well-known computer program for the machining or laser processing.

[0038] When manufacturing a plurality of, for example, several hundreds of tires 1 having the minute projections 11 shown in FIG. 3 continuously using the vulcanization mold, the rubber of the tire 1 may accumulate in the uneven portions. FIG. 4(a) shows a perspective view of the minute projection 11 formed by such uneven portions in which rubber has accumulated. This minute projection 11 is formed such that the projection height H1 is smaller than that of the minute projection 11 of the present embodiment. For this reason, the width W1 of the projection top 13 becomes slightly larger than the width W1 of the projection top 13 of the present embodiment (shown in FIG. 3). However, since the inner minute projection 19 is also provided in this embodiment, the attenuation effect due to the reflection of the light irradiated into the recess 15 is exhibited. For this reason, a high blackness degree is also exhibited in the minute projection 11 of this embodiment. In this case, it is desirable that the projection height H1 of the minute projection 11 shown in FIG. 4(a) is 40% or more of the projection height H1 of the minute projection 11 shown in FIG. 3, more desirably 45% or more, and still more desirably 50% or more.

[0039] FIG. 4(b) is a perspective view of the minute projection 11 of another embodiment. The same reference numerals may be given to the same components as those of the minute projection 11 of the present embodiment, and the description thereof may be omitted. The minute projection 11 shown in FIG. 4(b) is formed in an arcuate shape concave toward the inside of the inner minute projection 19 in a longitudinal section passing through the center of the inner top 20 in the side surface portion 21. Such a side surface portion 21 also exhibits the effect of ensuring the blackness degree.

[0040] FIG. 5(a) is a perspective view of the microprotrusion 11 of yet another embodiment. FIG. 5(b) is a plan view of the microprotrusion 11 of FIG. 5(a). FIG. 6(a) is a longitudinal sectional view of the microprotrusion 11 of FIG. 5(a). The same components as those of the microprotrusion 11 in this embodiment may be denoted by the same reference numerals and their description may be omitted. The microprotrusion 11 shown in FIGS. 5(a), (b), and FIG. 6(a) includes an inner microprotrusion 19 that is at least partially integrally formed with or in contact with the wall surface portion 16. The inner microprotrusion 19 of this embodiment can also make the bottom side of the recess 15 less visible and prevent reflection. Further, the inner microprotrusion 19 can attenuate the light irradiated into the recess 15 by reflection and further reduce the reflection of light from within the recess 15.

[0041] The inner microprotrusion 19 of this embodiment includes one end portion 23 integrally formed with the wall surface portion 16, the other end portion 24 facing the one end portion 23 and integrally formed with the wall surface portion 16, and a main portion 25 connecting the one end portion 23 and the other end portion 24. Since such an inner microprotrusion 19 is integrally formed with the wall surface portion 16, it has high rigidity. In the cross section of the inner microprotrusion 19, the main portion 25 has, for example, the same width w2 along its length.

[0042] The width w2 of the main portion 25 is desirably, for example, 40% or more of the diameter D4 at the protrusion top 13 of the recess 15, more desirably 50% or more, desirably 80% or less, and more desirably 70% or less. Since the width w2 of the main portion 25 is 40% or more and 80% or less of the diameter D4 at the protrusion top 13 of the recess 15, the rigidity of the inner microprotrusion 19 is ensured while the attenuation effect of light reflection is exerted.

[0043] Note that the inner microprotrusion 19 of this embodiment may be formed, for example, so as to be in contact with the wall surface portion 16. The above-mentioned "so as to be in contact with" means that, for example, in the deformation due to the rolling of the tire 1, they are separated to such an extent that the inner microprotrusion 19 and the wall surface portion 16 are in contact (not shown). Such an inner microprotrusion 19 also has high rigidity because one end portion 23 or the other end portion 24 is supported by the wall surface portion 16 due to the deformation of the tire 1.

[0044] The inner concave portions 15A of this embodiment are arranged on both sides in the width direction of the inner micro-projections 19. In this embodiment, each inner concave portion 15A has a semi-circular cross-section. Such inner concave portions 15A enhance the light reflection attenuation effect by the wall surface portion 16 and the side surface portion 21.

[0045] In this embodiment, the inner concave portions 15A have the same opening area in the projection height direction. As a result, the ratio of the light irradiated into the concave portion 15 being confined within the concave portion 15 increases, so the blackness degree of the decorative portion 10 is enhanced. Note that the inner concave portions 15A are not limited to such a mode. For example, a mode in which the opening area continuously decreases toward the inside in the projection height direction may also be used (shown in FIG. 6(b)).

[0046] FIG. 7 is a perspective view of the micro-projections 11 formed on the hundreds-th tire when a plurality of tires 1, for example, hundreds of tires 1, are continuously manufactured using a vulcanization mold for manufacturing the tire 1 having the micro-projections 11 shown in FIG. 5(a). These micro-projections 11 are formed with a projection height H1 smaller than that of the micro-projections 11 shown in FIG. 5(a). In the micro-projections 11 of this embodiment, a shape is formed in which a plurality of concave portions 15 are provided at the projection top portion 13. Each concave portion 15 extends in the projection height direction from the projection top portion 13. Even in such micro-projections 11, the blackness degree of the decorative portion 10 can be ensured. The micro-projections 11 shown in FIG. 7 are provided with two concave portions 15. In this embodiment, each concave portion 15 has a semi-circular cross-section. The semi-circular shape is formed by an arc portion 18a formed of a curve and a chord portion 18b connecting both ends of the arc portion 18a with a straight line. Each concave portion 15 is arranged, for example, in a state where the chord portions 18b face each other. In this embodiment, each chord portion 18b is arranged in parallel. The cross-sections of each concave portion 15 have the same shape in the projection height direction. Note that such micro-projections 11 may be formed on the first manufactured tire.

[0047] FIG. 8(a) is a perspective view of the microprotrusion 11 of yet another embodiment, and FIG. 8(b) is a plan view of FIG. 8(a). FIG. 9(a) is a cross-sectional view taken along line A-A of FIG. 8(a). The same reference numerals may be assigned to the same configuration as the microprotrusion 11 of the present embodiment, and the detailed description thereof may be omitted. As shown in FIGS. 8 and 9(a), the microprotrusion 11 of this embodiment is provided with a plurality of recesses 15, for example, two recesses 15. Each recess 15 extends, for example, in the protrusion height direction from the protrusion top 13. In this embodiment, each recess 15 has an elliptical cross-section. Each recess 15 has, for example, the same shape. In this embodiment, the microprotrusion 11 is formed such that the major axes F1 of the respective recesses 15 are parallel. Further, in the microprotrusion 11, for example, the minor axes F2 of the respective recesses 15 are arranged on a single straight line c. Such a microprotrusion 11 has high rigidity and high blackness. Note that the directions of the major axis F1 and the minor axis F2 of each recess 15 are not limited to such a mode.

[0048] In the present embodiment, the separation distance w2 in the direction of the minor axis F2 of each recess 15 gradually decreases from the minor axis F2 of the recess 15 toward both sides in the direction of the major axis F1 of the recess 15. Thereby, the rigidity of the microprotrusion 11 is maintained high.

[0049] Although not particularly limited, it is desirable that the minimum separation distance wa between the respective recesses 15 is smaller than the minor diameter T2 of the recess 15, for example. Thereby, the light reflection effect by the recess 15 is ensured highly. From the viewpoints of the reflection effect and ensuring the rigidity of the microprotrusion 11, it is desirable that the minimum separation distance wa is 15% or more of the maximum separation distance wb of the respective recesses 15, more desirably 20% or more, still more desirably 30% or more, desirably 50% or less, more desirably 45% or less, and still more desirably 40% or less.

[0050] Figure 9(b) shows micro-protrusions 11 of still another embodiment. The same components as those of the micro-protrusions 11 of this embodiment may be denoted by the same reference numerals and their detailed description may be omitted. As shown in Figure 9(b), the micro-protrusions 11 of this embodiment include an outer concave portion 15B extending from the top of the protrusion 13 and two inner concave portions 15A connected to the outer concave portion 15B and extending inward in the protrusion height direction. In this embodiment, the cross-section of each inner concave portion 15A is formed in an elliptical shape. The outer concave portion 15B is formed, for example, with a circular cross-section. Since the light entering the outer concave portion 15B is attenuated within the inner concave portion 15A, the effect of enhancing the blackness degree is exhibited. In this embodiment, the outer concave portion 15B and the inner concave portions 15A are formed with the same protrusion height. Each inner concave portion 15A of this embodiment has, for example, the same arrangement as each concave portion 15 shown in Figure 8(a).

[0051] When the tire 1 having the micro-protrusions 11 as shown in Figure 9(b) is continuously manufactured using the vulcanization mold, micro-protrusions 11 including two concave portions 15 extending from the top of the protrusion 13 as shown in Figure 8(a) are formed.

[0052] In this embodiment, it is desirable that the major axis T1 of each concave portion 15 is 0.10 mm or more, more desirably 0.15 mm or more, desirably 0.40 mm or less, and more desirably 0.35 mm or less. Since the major axis T1 of the concave portion 15 is 0.10 mm or more and 0.40 mm or less, the light irradiated inside the concave portion 15 is effectively attenuated, and the appearance performance of the decorative portion 10 can be ensured.

[0053] Also, in this embodiment, the ratio (T1 / T2) of the major axis T1 to the minor axis T2 of each concave portion 15 is desirably 1.2 or more, more desirably 1.3 or more, desirably 1.8 or less, and more desirably 1.7 or less. Since the ratio (T1 / T2) is 1.2 or more and 1.8 or less, the above-described action is effectively exhibited.

[0054] FIG. 10 is a plan view of the decorative part 10 having the minute protrusions 11 shown in FIG. 8(a). As shown in FIG. 10, in this embodiment, the inner minute protrusions 19 are arranged so as to have a different orientation from the inner minute protrusions 19 of the minute protrusions 11 adjacent thereto. Such an arrangement of the inner minute protrusions 19 helps to enhance the blackness degree of the decorative part 10. The "orientation" herein refers to the orientation of the virtual straight line n when the virtual straight line n connecting one end portion 23 and the other end portion 24 is provided in the cross section of the minute protrusion 11. The virtual straight line n is arranged so as to pass through the center of the protrusion top portion 13.

[0055] As described above, the particularly preferred embodiments of the present disclosure have been described in detail. However, the present disclosure is not limited to the illustrated embodiments and can be implemented in various forms by deformation.

Example

[0056] In order to confirm the effects of the present disclosure, a pneumatic tire having a decorative part on the outer surface of the sidewall part was prototyped. Then, a test was conducted on the visual recognition performance according to the blackness degree of the decorative part of each prototyped tire. Specifications other than those described in Table 1 are substantially the same for both the comparative example and the example. Arrangement number of minute protrusions: 2.6 pieces / mm 2 H1: 0.25 mm D1: 0.54 mm D2: 0.41 mm

[0057] <Visual recognition performance> The prototyped tires of each example were continuously produced 500 pieces by a well-known vulcanization mold having an inverted pattern of minute protrusions. An inspector visually observed the 500th prototyped tire produced from the side and evaluated the blackness degree of the decorative part by the sense of taste. The results are shown in scores with Comparative Example 1 being 100. The larger the numerical value, the more the decrease in the blackness degree of the decorative part is suppressed even in the case of continuous production, and the visual recognition performance is excellent. A score of 105 or more is a pass. The minute protrusions of Comparative Examples 2 and 3 are in a mode in which recesses are formed but no inner minute protrusions are provided. The test results are shown in Table 1.

[0058]

Table 1

[0059] It is understood that the tire of the example has superior visibility performance compared to the tire of the comparative example. In particular, it is understood that the micro-protrusions in Fig. 8(a) have the highest blackness degree. The larger the area reflecting the light of the micro-protrusions, the smaller the blackness degree and the worse the visibility. Further, the plurality of concave portions divide (attenuate) the light to increase the blackness degree. Furthermore, it can be understood that the inner micro-protrusions shown in Figs. 5(a), 8(a) and 9(b) are less likely to have rubber deposited in the uneven portions during tire manufacturing than those shown in Fig. 3.

[0060] [Appendix] The present disclosure includes the following aspects.

[0061] [Disclosure 1] A tire having a decorative portion on at least a part of the visible outer surface of the tire, wherein 2 to 10 micro-protrusions are arranged per 1 mm2 in the decorative portion, and at least one of the micro-protrusions is provided with a concave portion at the top of the protrusion, and inner micro-protrusions are arranged inside the concave portion. [Disclosure 2] The tire according to Disclosure 1, wherein the height of the inner micro-protrusion is 30% to 100% of the depth of the concave portion. [Disclosure 3] The concave portion includes a wall surface portion extending from the top of the protrusion to the root side of the micro-protrusion and a bottom portion continuous with the wall surface portion at the root side of the micro-protrusion, and the inner micro-protrusion extends from the bottom portion to the top of the protrusion without contacting the wall surface portion. The tire according to Disclosure 1 or 2. [Disclosure 4] The concave portion includes a wall surface portion extending from the top of the protrusion to the root side of the micro-protrusion and a bottom portion continuous with the wall surface portion at the root side of the micro-protrusion, and at least a part of the inner micro-protrusion is integrally formed with or in contact with the wall surface portion. The tire according to Disclosure 1 or 2. [Disclosure 5] The inner micro-protrusion includes one end portion that is integrally formed with or in contact with the wall surface portion, the other end portion that faces the one end portion and is integrally formed with or in contact with the wall surface portion, and a main portion that connects the one end portion and the other end portion. The tire according to Disclosure 4 [Disclosure 6] In the cross section of the inner micro-protrusion, the width of the main portion gradually increases from an intermediate position between the one end portion and the other end portion toward the one end portion side and the other end portion side. The tire according to Disclosure 5 [Disclosure 7] A tire having a decorative portion on at least a part of the visible outer surface of the tire. In the decorative portion, 2 to 10 micro-protrusions are arranged per 1 mm2, and at least one of the micro-protrusions is provided with a plurality of recesses extending in the protrusion height direction from the protrusion top [Disclosure 8] In the cross section of each of the plurality of recesses, the shape is elliptical. The tire according to Disclosure 7 [Disclosure 9] The major axis of each recess is 0.10 to 0.40 mm. The tire according to Disclosure 8 [Disclosure 10] The ratio of the major axis to the minor axis of each recess is 1.2 to 1.8. The tire according to Disclosure 8 or 9 [Disclosure 11] In the cross section of each of the plurality of recesses, the shape is semi-circular. The tire according to Disclosure 7

Description of Reference Numerals

[0062] 1 Tire 1a Outer surface 10 Decorative portion 11 Micro-protrusion 13 Protrusion top 15 Recess 19 Inner micro-protrusion

Claims

1. A tire, having a decorative portion on at least a part of the visible outer surface of the tire, wherein 2 to 10 micro-protrusions are arranged per 1 mm2 in the decorative portion, at least one of the micro-protrusions having a recess provided at the top of the protrusion, inner micro-protrusions being arranged inside the recess, the recess including a wall surface portion extending from the top of the protrusion toward the root side of the micro-protrusion and a bottom portion continuous with the wall surface portion at the root side of the micro-protrusion, at least a part of the inner micro-protrusions being integrally formed with or in contact with the wall surface portion, the inner micro-protrusions including one end portion integrally formed with or in contact with the wall surface portion, the other end portion facing the one end portion and integrally formed with or in contact with the wall surface portion, and a main portion connecting the one end portion and the other end portion, in a cross-section of the inner micro-protrusion, the width of the main portion increasing gradually from an intermediate position between the one end portion and the other end portion toward the one end portion side and the other end portion side, a tire.

2. The tire according to claim 1, wherein the height of the protrusion of the inner micro-protrusion is 30% to 100% of the depth of the recess.

Images