Tire and tire molding metal mold

Abstract

To provide a tire and a tire molding metal mold which can aim for high contrast because the black color concentration is even higher than before.SOLUTION: In a tire 1 which comprises a smooth area 8 including a smooth surface 8a and a pattern area 7 provided in a visible state as a part different from the smooth area 8 on an outside surface 3a of a side wall 3, the pattern area 7 contains a serration part 20 and the serration part 20 includes a plurality of main convex articles 21 which protrude from a reference plane 7a of the pattern area 7 and are disposed in parallel, trough parts 22 between the adjoining main convex articles 21 and irregularity parts 30 which are provided on the trough parts 22 and are larger than the smooth surface 8a in degree of the irregularity.SELECTED DRAWING: Figure 3

Description

[Technical Field]

[0001] The present invention relates to a tire having a pattern area for displaying, for example, a mark or a design on a part of the outer surface of the sidewall, and to a tire molding mold for molding such a tire. [Background technology]

[0002] Conventionally, tires have been known that have a pattern area in which a large number of minute protrusions are arranged in a portion of the tire sidewall (for example, Patent Document 1, etc.). Such pattern areas absorb light as incident light is repeatedly reflected between the protrusions, which makes the area appear darker than the surrounding outer surface of the sidewall, improving contrast. By providing this type of pattern area, the tire can be improved in terms of design effect and appearance, for example. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Publication No. 2020-131904 Summary of the Invention [Problem to be solved by the invention]

[0004] An object of the present invention is to provide a tire and a tire molding die that can achieve higher black density and higher contrast than conventional tires. [Means for solving the problem]

[0005] The tire according to the present invention is a tire comprising, on the outer surface of a sidewall, a smooth region having a smooth surface, and a pattern region provided in a state where it is visible as a part different from the smooth region, wherein the pattern region includes a serration portion, and the serration portion has a plurality of main ridges protruding from a reference surface of the pattern region and arranged in parallel, valley portions between adjacent main ridges, and uneven portions provided in the valley portions and having a degree of unevenness greater than that of the smooth surface.

[0006] A tire molding mold according to the present invention is a mold for molding the tire of the present invention, and includes a pattern area forming section for forming the pattern area. [Effects of the Invention]

[0007] According to the present invention, it is possible to provide a tire and a tire molding die that can achieve higher black density and higher contrast than conventional tires. [Brief explanation of the drawings]

[0008] [Figure 1] 1 is a side view of a tire according to an embodiment. [Figure 2] FIG. 1 is a cross-sectional view showing an example of a tire molding mold for vulcanizing and molding a tire according to an embodiment. [Figure 3] FIG. 2 is an enlarged perspective view showing a portion of a serration portion formed in a pattern region of the tire according to the embodiment. [Figure 4] 4 is a plan view showing a part of the serration portion according to the embodiment, taken along the arrow IV in FIG. 3. FIG. [Figure 5] FIG. 5 is a cross-sectional view of FIG. 4 . [Figure 6] FIG. 10 is an enlarged perspective view showing a portion of a serration portion formed in a pattern region of a tire according to another embodiment. [Figure 7] 7 is a plan view showing a part of a serration portion according to another embodiment, taken along arrow VII in FIG. 6. FIG. [Figure 8A] FIG. 8 is a cross-sectional view taken along the line VIIIA-VIIIA in FIG. 7. [Figure 8B] 8 is a cross-sectional view corresponding to the cross section VIIIA-VIIIA of FIG. 7, showing another example of a concave-convex portion having a plurality of minor convex stripes. FIG. [Figure 9] 5 is a cross-sectional view corresponding to the VV cross-sectional line in FIG. 4, showing a modified example in which the valleys of the serration portion have a V-shaped cross section and uneven portions are provided in the valleys by rough surfaces. FIG. [Figure 10] 5 is a cross-sectional view corresponding to the VV cross-sectional line in FIG. 4, showing a modified example in which the valley of the serration portion has a V-shaped cross section and the valley is provided with an uneven portion formed by a plurality of secondary convex stripes. DETAILED DESCRIPTION OF THE INVENTION

[0009] Hereinafter, embodiments will be described with reference to the drawings. Note that the term "approximately" used in this specification does not strictly specify the state, but rather means to include a state that is approximate to the extent that the functions and effects can be achieved.

[0010] FIG. 1 is a side view of a tire 1 according to an embodiment. The tire 1 is a so-called pneumatic tire whose inner cavity is filled with air at a predetermined pressure. The tire 1 according to the embodiment is a pneumatic tire for passenger vehicles, including light cars and SUVs. Note that the configuration of the tire 1 according to the embodiment can also be applied to pneumatic tires for other vehicle types, such as light trucks, trucks, and buses.

[0011] First, referring to FIG. 1, an overview of the configuration of the tire 1, mainly related to its side surface, will be described. FIG. 1 is a side view of the tire 1 as viewed from the direction of the tire rotational axis X. In the following description, the tire axial direction, tire circumferential direction, and tire radial direction are as follows: The tire axial direction is the direction in which the tire rotational axis X extends, and in FIG. 1 refers to the front-to-back direction of the page. When viewed from the tire radial direction, the tire axial direction is the left-to-right direction, and therefore may also be referred to as the left-to-right direction. The tire circumferential direction is an arc line centered on the tire rotational axis X and is the direction along the rotational direction of the tire 1, and is indicated by arrow G in FIG. 1. The tire radial direction is the direction perpendicular to the tire rotational axis X, and is arbitrarily indicated by arrow Y in FIG. 1.

[0012] As shown in Fig. 1, the tire 1 includes a bead 2, a sidewall 3 extending radially outward from the bead 2 away from the tire rotational axis X in the tire radial direction, and a tread 4. Each of the bead 2 and the sidewall 3 is provided on one side of the tire 1 shown in Fig. 1 on one side of the tire 1, and on the other side of the tire 1 not shown in Fig. 1 away from the tire axial direction, i.e., a pair of left and right bead 2 and sidewall 3. The tread 4 is disposed between the left and right sidewalls 3 on the outer sides in the tire radial direction. The outer peripheral surface of the tread 4 includes a tread surface that comes into contact with the road surface.

[0013] The tire 1 is mainly composed of multiple types of rubber that form the beads 2, sidewalls 3, and tread 4. A carcass ply that forms the framework of the tire 1 is disposed on the inner cavity side of the rubber that forms the entire tire 1, and an inner liner that maintains air pressure is disposed on the inner cavity side of the carcass ply. An annular reinforcing belt is embedded inside the rubber that forms the tread 4 (the carcass ply, inner liner, and reinforcing belt are not shown). In addition to these components, various other components may be provided as necessary for the function of the tire 1.

[0014] As shown in Fig. 1, the sidewall 3 has an annular decorative area 5 on its outer surface 3a, spanning the entire circumference in the tire circumferential direction. The decorative area 5 is an area of ​​a constant width sandwiched between an inner arc line 5a on the inner side in the tire radial direction and close to the tire rotation axis X, and an outer arc line 5b on the outer side in the tire radial direction than the inner arc line 5a. The inner arc line 5a and the outer arc line 5b may be lines formed by concavities, convexities, or steps on the outer surface 3a of the sidewall 3, or may be imaginary lines that do not actually exist.

[0015] The decorative area 5 on the outer surface 3a of the sidewall 3 may be located radially outward of the maximum tire width position or may be located at a position that includes the maximum tire width position. The maximum tire width position refers to the position between the outer surfaces 3a of the left and right sidewalls 3 that has the longest axial length.

[0016] The decorative region 5, which is part of the outer surface 3a of the sidewall 3, includes a smooth region 8 and a pattern region 7 that is provided in a visible state as a part different from the smooth region 8. The smooth region 8 and the pattern region 7 are provided in the sidewall rubber, which is a black rubber member that forms the outer surface 3a of the sidewall 3.

[0017] The smooth region 8 that is part of the decorative region 5 has a smooth surface 8 a that is a smooth surface that follows the profile of the sidewall 3 .

[0018] As shown in FIG. 1 , the annular decorative region 5 is provided with marking portions 6A at two opposing locations across the tire rotation axis X. The marking portions 6A are formed by a plurality of characters arranged in the tire circumferential direction. These characters indicate at least one mark such as the manufacturer's name, product name, or brand. Each character may be formed with a concave or convex border, or the entire character may be formed in a concave or convex shape. For example, each character in the marking portion 6A is provided as the pattern region 7 of the embodiment.

[0019] 1, pattern portions 6B are provided in two locations in the annular decorative area 5, sandwiched between two marking portions 6A in the circumferential direction. The pattern portions 6B are provided with a pattern that resembles a parallelogram curved to imitate the annular decorative area 5. For example, each pattern in the pattern portions 6B is also provided as the pattern area 7 of the embodiment.

[0020] The shape of the pattern area 7 is not limited to these, and may be any shape, or a shape depicting marks such as the manufacturer name, product name, brand, etc., as mentioned above, or a shape depicting other numbers, letters, etc.

[0021] Each of the pattern regions 7 in the embodiment has a reference surface 7a that follows the profile of the sidewall 3. A serration portion 20, which will be described later, is provided on the reference surface 7a of the pattern region 7. By providing the serration portion 20, the pattern region 7 is an area that is provided in a state where it can be visually recognized as a part that is different from the smooth region 8.

[0022] The reference surface 7a may protrude axially outward from the profile of the sidewall 3, may be recessed axially inward from the profile of the sidewall 3, or may be a surface that is at the same position in the axial direction as the profile of the sidewall 3.

[0023] Fig. 2 shows an example of a tire molding mold for vulcanizing and molding the tire 1 of the embodiment. Fig. 2 is a meridian cross-sectional view of such a tire molding mold 10 taken along the axial direction of the tire 1 to be molded.

[0024] The tire mold 10 shown in Fig. 2 includes a plurality of sectors 11 arranged circumferentially along the outer periphery of the tire 1, a pair of side plates 12 arranged on both axial sides of an annular body formed by combining the plurality of sectors 11, and a pair of bead rings 13. During vulcanization molding, an unvulcanized tire 1a that will become the tire 1 is set inside the tire mold 10, as indicated by the dashed line in Fig. 2. The combination of the sectors 11, the side plates 12, and the pair of bead rings 13 forms a mold for molding the tire 1, and the outer surface of the entire tire 1 is formed by the inner surfaces of the mold, i.e., the inner surfaces 11a of the sectors 11, the inner surfaces 12a of the side plates 12, and the inner surfaces 13a of the bead rings 13. During vulcanization molding, a bladder 14 is arranged inside the unvulcanized tire 1a to press the unvulcanized tire 1a against the inner surface of the tire mold 10. The plurality of sectors 11 mainly form the tread 4, the pair of side plates 12 mainly form the sidewall 3, and the pair of bead rings 13 mainly form the bead 2. The entire inner surface of the tire 1 is then formed by the bladder 14.

[0025] The unvulcanized tire 1a is vulcanized by the tire molding mold 10 to form the rubber shape of the entire tire 1. In the pattern region 7 of the tire 1 of the embodiment molded by the tire molding mold 10, a serration portion 20 is formed.

[0026] Fig. 3 is a perspective view showing a part of the serration portion 20 formed in the pattern region 7. Fig. 4 is a plan view showing a part of the serration portion 20, taken along the line IV in Fig. 3. FIG. 5 is a cross-sectional view taken along line VV in FIG.

[0027] 3 and 4 show a state in which the serration portion 20 is provided on a UV development reference surface 7b when the reference surface 7a of the pattern area 7 is UV developed. The UV development reference surface 7b is a surface obtained by two-dimensionally developing the outer surface 3a of the three-dimensional sidewall 3. As shown in FIGS. 3 to 5, the serration portion 20 has a plurality of main ridges 21, valleys 22 between adjacent main ridges 21, and uneven portions 30 provided in each valley 22.

[0028] The main ridge 21 of the embodiment is a protrusion that protrudes from the reference surface 7a substantially axially outward and extends linearly. The cross section of the main ridge 21 is mountain-shaped and has a substantially isosceles triangle shape. The main ridge 21 has a ridge-like apex 21a, a pair of sloped side surfaces 21b that extend from the apex 21a toward the valleys 22 on both sides, and a band-shaped imaginary bottom surface 21c that is integral with and flush with the reference surface 7a. The multiple main ridges 21 are arranged parallel to each other. The multiple main ridges 21 of the embodiment have substantially uniform cross-sectional shapes and dimensions. The multiple main ridges 21 of the embodiment have substantially the same spacing (equal pitch) between adjacent main ridges 21.

[0029] The valleys 22 formed between adjacent main ridges 21 are formed by the side surfaces 21b and valley bottoms 22a of the adjacent main ridges 21. The surface roughness of the top surfaces 21a and the pair of side surfaces 21b of the main ridges 21 is preferably, for example, Ra: 0.7 μm or more and 1.5 μm or less. The valley bottoms 22a of the valleys 22 are formed by a strip-shaped surface having a predetermined width, and the surface is generally flat and substantially aligned with the reference surface 7a.

[0030] The valley bottom 22a of the valley portion 22 may be at a height position along the reference surface 7a, or may be at a position that protrudes further toward the tire outer surface than the reference surface 7a, or may be at a position that is recessed further toward the tire cavity than the reference surface 7a.

[0031] The dimensions of the main ridges 21 and valleys 22 that make up the serration portion 20 are not limited, but for example, the height of the main ridges 21 from the reference plane 7a is preferably 0.2 mm to 1.5 mm, and the width (width of the bottom surface 21c) is preferably 0.2 mm to 1.0 mm. The width of the valley bottoms 22a is preferably 0.3 mm to 5.0 mm, for example. The spacing (pitch) between the main ridges 21, i.e., the spacing between the peaks 21a of adjacent main ridges 21, is preferably 0.5 mm to 3.0 mm, for example. The length of the main ridges 21 depends on the shape and dimensions of the pattern region 7, etc.

[0032] As shown in FIG. 5 , the uneven portion 30 is provided at the valley bottom 22a of the valley portion 22. As described above, the surface of the valley bottom 22a is generally flat and generally conforms to the reference plane 7a. However, strictly speaking, the valley bottom 22a includes a rough surface 31 having the uneven portion 30. The rough surface 31 has a plurality of minute protrusions 31a and a plurality of minute recesses 31b dispersed in the valley bottom 22a. That is, the valley bottom 22a, in which the plurality of minute protrusions 31a and minute recesses 31b are dispersed, is formed as the rough surface 31 having a predetermined roughness. The rough surface 31 has a greater degree of unevenness than the smooth surface 8a of the smooth region 8. The roughness of the rough surface 31 is not limited, but is preferably, for example, Ra: 3.0 μm or more and 7.0 μm or less.

[0033] As described above, the surface roughness of the crests 21a and side surfaces 21b of the main ridges 21 is preferably, for example, Ra: 0.7 μm or more and 1.5 μm or less. The surface roughness of the roughened surfaces 31 of the valley bottoms 22a is not limited, but it is preferable that the surface roughness of the crests 21a and side surfaces 21b of the main ridges 21 be 3 times or more and 10 times or less, and more preferably 3 times or more and 5 times or less, of the surface roughness of the roughened surfaces 31 of the valley bottoms 22a. In other words, the surface roughness of the roughened surfaces 31 of the valley bottoms 22a is preferably 1 / 10 to 1 / 3, and more preferably 1 / 5 to 1 / 3, of the surface roughness of the crests 21a and side surfaces 21b of the main ridges 21.

[0034] The serration portion 20 of the embodiment can be formed, for example, by the tire molding mold 10 described above. To form the serration portion 20 by the tire molding mold 10, a plurality of groove-like recesses that correspond to the plurality of main ridges 21 and that can form the main ridges 21, and a rough surface that corresponds to the rough surfaces 31 of the plurality of uneven portions 30 and that can form the rough surfaces 31, are formed on the inner surface 12a, which is the tire molding surface, of the side plate 12 that forms the pattern region 7. In other words, the inner surface 12a of the side plate 12 includes a pattern region forming portion that forms the plurality of main ridges 21 and the rough surfaces 31 of the plurality of uneven portions 30.

[0035] The method for forming the recesses corresponding to the main ridges 21 and the rough surfaces corresponding to the rough surfaces 31 of the uneven portions 30 on the inner surface 12a of the side plate 12 in the tire molding mold 10 is not limited.

[0036] For example, in the case of recesses corresponding to the main ridges 21, laser processing can be used in which laser light is irradiated onto the inner surface 12a of the side plate 12 to partially remove the inner surface 12a. For example, a pulsed fiber laser can be used as the laser processing method. The laser processing conditions are preferably, for example, a central wavelength of 1080 nm, an average power of 100 W or more and 300 W or less, and a laser spot diameter of approximately 0.05 mm. In this case, the recesses corresponding to the main ridges 21 can be suitably formed by adjusting the power of each pulse or the irradiation angle of the laser light. By forming multiple recesses, which can form multiple main ridges 21, on the inner surface 12a of the side plate 12 by laser processing, the side plate 12 is hardened, thereby improving its durability.

[0037] For example, the recesses corresponding to the main ridges 21 may be formed on the inner surface 12a of the side plate 12 by machining such as cutting.

[0038] For example, when a rough surface corresponding to the rough surface 31 of the uneven portion 30 is formed on the inner surface 12a of the side plate 12, it can be formed by, for example, sandblasting the inner surface 12a.

[0039] As described above, the tire 1 of the embodiment is provided with serration portions 20 each having a plurality of main ridges 21 and each having an uneven portion 30 in each of the valleys 22 between the main ridges 21 in each of the plurality of pattern regions 7 arranged on the sidewall 3. In such a tire 1, when light is incident on the pattern region 7, the light is incident on the plurality of main ridges 21 and the plurality of uneven portions 30 of the serration portion 20 and is reflected. The reflected light is then reflected again by adjacent main ridges 21 and uneven portions 30, and such reflection of light occurs repeatedly between the main ridges 21 and between the main ridges 21 and the uneven portions 30. As a result, the light incident on the pattern region 7 is gradually attenuated and absorbed. When such a pattern region 7 is visually observed, the pattern region 7 appears darker than the smooth region 8 surrounding the pattern region 7 and the outer surface 3a of the sidewall 3 including the smooth region 8.

[0040] In the tire 1 of this embodiment, the valley bottoms 22a of the valleys 22 between adjacent main ridges 21 are formed with uneven portions 30, including rough surfaces 31 with a surface roughness smaller than that of the peaks 21a and side surfaces 21b of the main ridges 21. This makes light reflection more complex, particularly at the uneven portions 30 of the valleys 22, and facilitates diffuse reflection, thereby promoting light absorption. This further increases the black density of the pattern region 7, thereby enhancing contrast. Furthermore, a contrast is created between the peaks 21a and side surfaces 21b of the main ridges 21 and the uneven portions 30 of the valleys 22, thereby creating a contrast between the pattern region 7 and the smooth region 8. In particular, the surface roughness of the rough surfaces 31 of the valley bottoms 22a is between 1 / 10 and 1 / 3 of the surface roughness of the peaks 21a and side surfaces 21b of the main ridges 21, thereby providing a sufficient level of contrast.

[0041] Next, another embodiment based on the above embodiment will be described with reference to Figures 6 to 8B. In this other embodiment, the configuration of the uneven portion 30 of the serration portion 20 differs from that of the above embodiment, but the other configurations are the same. Therefore, the following description will mainly focus on the uneven portion 30, which is different from the above embodiment, and descriptions of the other configurations will be simplified or omitted. Note that in the reference drawings, the same components as those in the above embodiment are designated by the same reference numerals.

[0042] Fig. 6 is a perspective view showing a part of a serration portion 20 according to another embodiment. Fig. 7 is a plan view showing a part of the serration portion 20, taken along the arrow VII in Fig. 6. Fig. 8A is a cross-sectional view taken along the line VIIIA-VIIIA in Fig. 7.

[0043] As shown in Figures 6 to 8A, the uneven portion 30 provided in the valley bottom 22a of each valley portion 22 between multiple main ridges 21 has multiple secondary ridges 35 and groove portions 36 between adjacent secondary ridges 35.

[0044] The secondary ridge 35 is a protrusion that protrudes from the reference surface 7a substantially axially outward of the tire and extends linearly. The cross section of the secondary ridge 35 is mountain-shaped and has a substantially isosceles triangle shape.

[0045] As shown in FIG. 8A , the secondary ridges 35 have a ridge-like apex 35a, a pair of sloped side surfaces 35b extending from the apex 21a toward the grooves 36 on both sides, and a band-like imaginary bottom surface 35c that is integral with the reference surface 7a and is flush with the reference surface 7a. The secondary ridges 35 extend in a direction substantially perpendicular to the extension direction of the primary ridges 21 and are arranged parallel to each other. By arranging the secondary ridges 35 closely together, the grooves 36 are formed with a V-shaped cross section. The grooves 36 are formed by the side surfaces 35b of adjacent secondary ridges 35. In this embodiment, the uneven portion 30, which includes the secondary ridges 35 and the grooves 36, has a greater degree of unevenness than the smooth surface 8a of the smooth region 8.

[0046] The cross-sectional shapes and dimensions of the multiple minor ridges 35 are substantially uniform. The distances between adjacent minor ridges 35 are substantially the same (equal pitch). The grooves 36 formed between adjacent minor ridges 35 are formed by the side surfaces 35b of the adjacent minor ridges 35. Note that the grooves 36 may have groove bottoms 36a that are flat surfaces, as shown in FIG. 8B.

[0047] The height of the secondary ridges 35 from the reference plane 7a and the valley bottoms 22a is not limited, but may be, for example, approximately 50% of the height of the primary ridges 21. A specific height of, for example, 0.1 mm or more and 0.6 mm or less is preferable. The width of the secondary ridges 35 (width of the bottom surface 35c) is preferably 0.5 mm or more and 2.5 mm or less. When the grooves 36 have groove bottoms 36a as shown in FIG. 8B, the width of the groove bottoms 36a is preferably 0.2 mm or more and 1.5 mm or less. The length of the secondary ridges 35 depends on the spacing between the primary ridges 21.

[0048] In addition, the secondary ridge 35 may have a length that extends between adjacent main ridges 21 and is integral with those main ridges 21, or it may be integral with one main ridge 21 and separate from the other main ridge 21, or it may be separate from both main ridges 21.

[0049] Like the main ridges 21 in the above-described embodiment, the secondary ridges 35 of the uneven portion 30 here can be formed by laser processing the inner surface 12a of the side plate 12 of the molding die 10. That is, recesses corresponding to the multiple secondary ridges 35 are formed on the inner surface 12a of the side plate 12, and the tire 1 is then vulcanized to form the multiple secondary ridges 35 and the grooves 36 between the secondary ridges 35.

[0050] According to the other embodiment described above, light incident on the pattern region 7 is gradually attenuated and absorbed by being incident on and reflected by the plurality of main convex ridges 21 and the plurality of concave-convex portions 30 of the serration portion 20. When such a pattern region 7 is visually observed, the pattern region 7 appears darker than the smooth region 8 around the pattern region 7 and the outer surface 3a of the sidewall 3 including the smooth region 8.

[0051] In the uneven portion 30, light reflected by the peaks 35a and side surfaces 35b of multiple minor protrusions 35 is reflected again by the peaks 35a and side surfaces 35b of adjacent minor protrusions 35. This type of light reflection occurs repeatedly between the minor protrusions 35, making the light reflection complex and prone to diffuse reflection, thereby promoting light absorption. The presence of groove bottoms 36a between adjacent minor protrusions 35, as shown in FIG. 8B, further promotes light absorption due to diffuse reflection. This further increases the black density of the pattern region 7, thereby achieving high contrast. Furthermore, a contrast is created between the peaks 21a and side surfaces 21b of the main protrusions 21 and the uneven portion 30, thereby creating a contrast between the pattern region 7 and the smooth region 8.

[0052] In the tire 1 of each of the above-described embodiments, including other embodiments, the valley bottoms 22a of the valleys 22 of the serration portion 20 are generally planar along the reference plane 7a, but the valley bottoms 22a are not limited to being planar and may have, for example, a V-shaped or U-shaped cross-sectional shape. Figures 9 and 10 are cross-sectional views corresponding to the VV cross-sectional line in Figure 4, and show modified examples in which the valley bottoms 22a have a V-shaped cross section. The height position of the deepest part of the valley bottoms 22a is substantially the same as the reference plane 7a.

[0053] 9 shows an example in which the valley bottoms 22a of the valleys 22 between adjacent main ridges 21 have a V-shaped cross section, and the roughened surfaces 31 on which a plurality of minute protrusions 31a and a plurality of minute recesses 31b are dispersed, as in the above-described embodiment, are formed on the surfaces of the valley bottoms 22a, as the uneven portion 30. The roughened surfaces 31 are formed on a pair of side surfaces 21b of a pair of adjacent main ridges 21 that face each other to form the valleys 22. In this case, the uneven portion 30 including the roughened surfaces 31 is preferably formed in a region extending from the deepest part of the valley bottoms 22a to, for example, 50% or less of the height of the main ridges 21.

[0054] 10 shows an example in which the valley bottoms 22a of the valleys 22 between adjacent main ridges 21 have a V-shaped cross section, and the valley bottoms 22a are formed with an uneven portion 30 having a plurality of secondary ridges 35 and grooves 36 between the adjacent secondary ridges 35, as in the other embodiment described above. The uneven portion 30 is formed on a pair of side surfaces 21b of a pair of adjacent main ridges 21 that face each other to form the valleys 22. In this case, the uneven portion 30 including the secondary ridges 35 is preferably formed in a region extending from the deepest part of the valley bottoms 22a to, for example, 50% or less of the height of the main ridges 21.

[0055] 9 and 10, the concave-convex portions 30 face each other across the valleys 22. This causes light to be reflected in a complex manner between the facing concave-convex portions 30, further promoting the light absorption effect due to the diffused reflection of light. This further increases the black density of the pattern region 7, thereby achieving high contrast.

[0056] The tire 1 described above provides the following effects.

[0057] The tire 1 according to the embodiment is a tire having, on the outer surface 3a of the sidewall 3, a smooth region 8 having a smooth surface 8a, and a pattern region 7 arranged in a state that is visibly different from the smooth region 8, and the pattern region 7 includes a serration portion 20, and the serration portion 20 protrudes from the reference surface 7a of the pattern region 7 and has a plurality of main ridges 21 arranged in parallel, valley portions 22 between adjacent main ridges 21, and uneven portions 30 arranged in the valley portions 22 and having a greater degree of unevenness than the smooth surface 8a.

[0058] According to the tire 1 of the embodiment, the plurality of main ridges 21 absorb light, increasing the black density of the pattern region 7 and achieving high contrast. Furthermore, the uneven portions 30 between the main ridges 21 promote light absorption, further increasing the black density and further achieving high contrast in the pattern region 7. This allows the tire 1 to have improved design effects and appearance.

[0059] (2) In the tire 1 according to the embodiment (1), the uneven portion 30 includes a form having a rough surface 31 in which a plurality of minute protrusions 31a and minute recesses 31b are dispersed.

[0060] This improves the absorption of light incident on the pattern area 7, increasing the black density of the pattern area 7 and achieving high contrast.

[0061] (3) In the tire 1 of embodiment (1) above, the uneven portion 30 may have a configuration having a plurality of secondary ridges 35 extending in a direction intersecting the main ridges 21 of the serration portion 20, and groove portions 36 between adjacent secondary ridges 35.

[0062] This improves the absorption of light incident on the pattern area 7, increasing the black density of the pattern area 7 and achieving high contrast.

[0063] (4) In the tire 1 according to the embodiment (1) to (3) above, the valley bottoms 22a of the valleys 22 of the serration portion 20 may be flat.

[0064] This improves the absorption of light incident on the pattern area 7, increasing the black density of the pattern area 7 and achieving high contrast.

[0065] (5) In the tire 1 according to the embodiment (1) to (3) above, the valley bottoms 22a of the valleys 22 of the serration portion 20 may have a V-shaped cross section.

[0066] This improves the absorption of light incident on the pattern area 7, increasing the black density of the pattern area 7 and achieving high contrast.

[0067] (6) The tire molding mold 10 according to the embodiment is a mold for molding the tire 1 described above in (1) to (5), and has an inner surface 12a of a side plate 12 as a pattern area forming portion that forms the pattern area 7 of the tire 1.

[0068] According to the tire molding mold 10 of the embodiment, the serration portion 20 of the embodiment is provided by the inner surface 12a of the side plate 12. This makes it possible to mold a tire 1 in which the black density of the pattern region 7 including the serration portion 20 is increased, thereby achieving high contrast.

[0069] Although the embodiments of the present invention have been described above, the present invention is not limited to the above-described embodiments, and any modifications and improvements made within the scope of the present invention are included within the scope of the present invention.

[0070] For example, the intervals (pitch) between the multiple main ridges 21 arranged in the pattern region 7 may be non-uniform, and they may not be arranged in parallel. The cross-sectional shapes, dimensions, etc. of the multiple main ridges 21 may also be non-uniform. Similarly, the multiple secondary ridges 35 in other embodiments may also be non-uniform in terms of the intervals, cross-sectional shapes, dimensions, etc.

[0071] The cross-sectional shape of the main convex ribs 21 and the sub-convex ribs 35 is not limited to a substantially isosceles triangle, but may be various other shapes, such as a rectangle including a trapezoid, a polygon, or a semicircular arc. [Explanation of symbols]

[0072] 1 tire 3 Sidewall 3a Outer surface of sidewall 7 Pattern Area 7a Reference surface of pattern area 8 Smooth region 8a Smooth surface 10 Tire molding mold 12a Inner surface of side plate (pattern area forming portion) 20 Serration section 21 Main ridge 22 Valley 22a Valley bottom 30 Uneven part 31 Rough surface 31a Microprotrusion 31b Micro recess 35 Sub-protrusion 36 Groove

Claims

1. A tire having a smooth region having a smooth surface on the outer surface of a sidewall, and a pattern region provided in a visibly recognizable state as a portion different from the smooth region, the pattern region includes a serration portion, The serration portion is a plurality of main protrusions arranged in parallel and projecting from a reference surface of the pattern area; a valley portion between adjacent main ridges; and an uneven portion provided in the valley portion, the uneven portion having a degree of unevenness greater than that of the smooth surface.

2. The tire according to claim 1 , wherein the uneven portion has a rough surface with a plurality of minute protrusions and minute recesses dispersed therein.

3. The tire according to claim 1 , wherein the uneven portion has a plurality of minor ridges extending in a direction intersecting the major ridges of the serration portion, and grooves between adjacent minor ridges.

4. The tire according to claim 1 or 2, wherein the bottoms of the valleys of the serration portion are flat.

5. The tire according to claim 1 or 2, wherein the bottoms of the valleys of the serration portion have a V-shaped cross section.

6. A mold for molding the tire according to any one of claims 1 to 3, comprising a pattern area forming portion that forms the pattern area.

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