Tire and tire molding die

Abstract

To provide a tire which is enhanced in black color density to enhance contrast more than before.SOLUTION: A tire 1 comprises, on a portion of an outer surface 3a of a side wall 3, a pattern region 7 formed visibly as a site that is different from a circumference of the portion, where a plurality of oblique conical bodies 20 are each arranged on a UV expansion reference surface 7b in a state where a reference surface 7a of the pattern region 7 is subjected to UV deployment so that apex parts 22 thereof are furthest away from a UV deployment reference surface 7b. The plurality of oblique conical bodies 20 have central shaft lines 20c through which the apex parts of the oblique conical bodies 20 are joined to a center of a bottom surface 23. The plurality of oblique conical bodies 20 are three or more kinds having different angles pf the central shaft lines 20c with respect to the UV deployment reference surface 7b.SELECTED DRAWING: Figure 3

Description

Technical Field

[0001] The present invention relates to a tire having a pattern area for displaying, for example, a logo, a pattern, etc. on a part of the outer surface of a sidewall, and a tire molding die for molding such a tire.

Background Art

[0002] Conventionally, a tire having a pattern area in which a large number of fine protrusions are gathered on a part of the sidewall of a tire is known (for example, Patent Document 1, etc.). In such a pattern area, the incident light is repeatedly reflected between the protrusions, resulting in a light absorption effect, whereby it is visually recognized as blacker than the outer surface of the surrounding sidewall, and the contrast is improved. By providing this type of pattern area, the tire can be improved in, for example, design effect and appearance.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] High contrast by a large number of protrusions has an advantage that it is less likely to undergo aging changes than means such as painting, and its effect is exerted over a long period of time. Therefore, there has been a demand for the formation of a pattern area by protrusions in which the black density is increased and the contrast is further improved compared to the conventional case, so as to further improve the design effect and appearance.

[0005] An object of the present invention is to provide a tire in which the black density is increased and high contrast is achieved compared to the conventional case, and a tire molding die capable of manufacturing such a tire.

Means for Solving the Problems

[0006] The tire according to the present invention is a tire provided with a pattern area provided in a visible state as a part different from the periphery of a part on the outer surface of the sidewall, and when the reference plane of the pattern area is UV-unrolled, each of a plurality of frustum cones is arranged in a state where its top is farthest from the UV-unrolled reference plane.

[0007] The tire molding die according to the present invention is a die for molding the tire of the present invention, and includes a frustum cone forming portion including a plurality of recesses corresponding to the plurality of frustum cones.

Effect of the Invention

[0008] According to the present invention, it is possible to provide a tire in which the black density is increased and high contrast is achieved more than before, and a tire molding die capable of manufacturing such a tire.

Brief Description of the Drawings

[0009]

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Mode for Carrying Out the Invention

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

[0011] First, with reference to FIG. 1, an outline of the configuration mainly related to the side surface of the tire 1 will be described. FIG. 1 is a side view of the tire 1 viewed from the direction of the tire rotation axis X. In the following description, the tire axial direction, the tire circumferential direction, and the tire radial direction are as follows. The tire axial direction is the direction in which the tire rotation axis X extends, and in FIG. 1, it refers to the front and back directions of the paper surface. Since the tire axial direction becomes the left and right directions when viewed from the tire radial direction, the tire axial direction may be referred to as the left and right directions. The tire circumferential direction is an arc line centered on the tire rotation axis X and is the direction along the rotation direction of the tire 1, which is indicated by an arrow G in FIG. 1. The tire radial direction is the direction perpendicular to the tire rotation axis X, which is arbitrarily indicated by an arrow Y in FIG. 1.

[0012] As shown in FIG. 1, the tire 1 includes a bead 2, a sidewall 3 extending radially outward of the tire from the bead 2 in the tire radial direction away from the tire rotation axis X, and a tread 4. Each of the bead 2 and the sidewall 3 has a pair, i.e., a left and a right one, respectively, on the side of one side surface 1s of the tire 1 shown in FIG. 1 and on the side of the other side surface not shown in FIG. 1 that is axially separated from the tire. The tread 4 is disposed between the left and right sidewalls 3 on the outer side in the tire radial direction. The outer peripheral surface of the tread 4 includes a tread surface that contacts the road surface.

[0013] The tire 1 is mainly composed of a plurality of types of rubber that constitute the bead 2, the sidewall 3, and the tread 4, respectively. A carcass ply that constitutes the skeleton of the tire 1 is disposed on the inner cavity side of the rubber that constitutes the entire tire 1, and an inner liner that holds air pressure is disposed on the inner cavity side of the carcass ply. Further, an annular reinforcing belt is embedded inside the rubber that constitutes the tread 4 (the carcass ply, the inner liner, and the reinforcing belt are not shown). In addition to these members, various members are provided as necessary for the function of the tire 1.

[0014] As shown in FIG. 1, the sidewall 3 has an annular decorative region 5 on its outer surface 3a over the entire circumference in the tire circumferential direction. The decorative region 5 is a region with a certain width sandwiched between an inner arc line 5a on the inner side in the tire radial direction that is close to the tire rotation axis X in the tire radial direction and an outer arc line 5b on the outer side in the tire radial direction that is more radially outward than the inner arc line 5a. The inner arc line 5a and the outer arc line 5b may be lines formed on the outer surface 3a of the sidewall 3 by concave, convex, or steps, or may be virtual lines that do not actually exist.

[0015] The tire radial position of the decorative region 5 on the outer surface 3a of the sidewall 3 may be on the outer side in the tire radial direction than the position of the maximum tire width, or may be at a position including the maximum tire width position. The maximum tire width position refers to the position where the axial length of the tire is the longest between the outer surfaces 3a of the left and right sidewalls 3.

[0016] The tire 1 includes a pattern area 7 provided on a part of the outer surface 3a of the sidewall 3 in a state visible as a part different from the periphery thereof. The pattern area 7 is provided on the sidewall rubber which is a black rubber member constituting the outer surface 3a of the sidewall 3.

[0017] As shown in FIG. 1, emblem portions 6A are provided at two locations of the annular decorative area 5 facing each other across the tire rotation axis X. The emblem portions 6A are formed by arranging a plurality of characters in the tire circumferential direction. At least one of emblems such as a manufacturer name, a product name, a brand, etc. is displayed by these plurality of characters. Each character may be formed by being outlined by a concave or convex line, or the whole character may be formed in a concave or convex shape. For example, each character of the emblem portion 6A is provided as the pattern area 7 of the embodiment.

[0018] As shown in FIG. 1, in the annular decorative area 5, pattern portions 6B are provided at two locations sandwiched between the two emblem portions 6A in the circumferential direction. The pattern portion 6B is provided with a pattern such that a parallelogram is curved following the annular decorative area 5. For example, each pattern of the pattern portion 6B is also provided as the pattern area 7 of the embodiment.

[0019] Note that the shape of the pattern area 7 is not limited to these, and various shapes can be mentioned, such as an arbitrary shape, a shape depicting an emblem such as the manufacturer name, product name, brand, etc. described above, or a shape depicting other numbers, characters, etc.

[0020] Each of the above pattern areas 7 in the embodiment has a reference plane 7a along the profile of the sidewall 3. A plurality of frustum cones 20 described later are formed on this reference plane 7a. The pattern area 7 is an area provided in a state visible as a part different from the periphery of the pattern area 7 by forming a plurality of frustum cones 20.

[0021] FIG. 2 shows an example of a tire molding die for vulcanizing and molding the tire 1 of the embodiment. FIG. 2 is a meridian cross-sectional view of such a tire molding die 10 along the axial direction of the tire 1 to be molded.

[0022] The tire molding die 10 shown in FIG. 2 includes a plurality of sectors 11 arranged circumferentially along the outer peripheral side of the tire 1, a pair of side plates 12 arranged on both axial sides of the annular body formed by the combination of the plurality of sectors 11, and a pair of bead rings (not shown). During vulcanization molding, as shown by the dashed line in FIG. 2, an unvulcanized tire 1a that will become the tire 1 is set inside the tire molding die 10. The combination of the sectors 11, the side plates 12, and the bead rings is a molding die for molding the tire 1, and the outer surface of the entire tire 1 is molded by the inner surfaces of the molding die, that is, the inner surface 11a of the sectors 11, the inner surface 12a of the side plates 12, and the inner surface of the bead rings. Also, during vulcanization molding, a bladder (not shown) that presses the unvulcanized tire 1a against the inner surface of the tire molding die 10 is arranged inside the unvulcanized tire 1a. The plurality of sectors 11 mainly form the tread 4, and the pair of side plates 12 mainly form the sidewall 3. The pair of bead rings form the bead 2, and the bladder forms the entire inner surface of the tire 1.

[0023] The unvulcanized tire 1a is vulcanized by the tire molding die 10 to form the rubber shape of the entire tire 1, and a plurality of frustum cones 20 described below are formed in the above-mentioned pattern region 7.

[0024] FIGS. 3 to 6 are views showing a plurality of frustum cones 20 arranged in a part of the pattern region 7. FIG. 3 is a perspective view, FIG. 4 is a plan view and is a view taken along the arrow IV in FIG. 3, FIG. 5 is a side view and is a view taken along the arrow V in FIG. 3, and FIG. 6 is a side view and is a view taken along the arrow VI in FIG. 3. FIG. 7 is a side view excerpting a plurality of types (in this case, 4 types) of frustum cones 20 with different inclination angles.

[0025] A plurality of frustum cones 20 are arranged in the pattern region 7 in a state of filling the entire area of the pattern region 7. Although the plurality of frustum cones 20 are protrusions protruding from the reference plane 7a of the pattern region 7, FIGS. 3 to 6 show a state in which the plurality of frustum cones 20 protrude from the UV development reference plane 7b when the reference plane 7a of the pattern region 7 is UV developed. The UV development reference plane 7b is a plane obtained by two-dimensionally developing the outer surface 3a of the three-dimensional side wall 3. The plurality of frustum cones 20 are arranged in a random, i.e., scattered, state on this UV development reference plane 7b without taking a specific arrangement form.

[0026] As shown in FIG. 7, the frustum cone 20 has a conical shape, and its central axis 20c is inclined with respect to the UV development reference plane 7b. FIG. 7 is a schematic diagram in which the inclination directions of the frustum cones 20 are aligned in either the left or right direction. That is, each central axis 20c shown in FIG. 7 extends along the plane of the paper of FIG. 7. Each of the frustum cones 20 has a skirt portion 24 continuous with the UV development reference plane 7b.

[0027] As shown in FIGS. 3 to 6, each of the plurality of frustum cones 20 is a conical protrusion protruding from the UV development reference plane 7b. As shown in FIG. 7, each frustum cone 20 has a conical side surface 21 and a top portion 22 formed by being flatly cut. For each of the frustum cones 20, its top portion 22 is arranged on the UV development reference plane 7b in a state of being farthest from the UV development reference plane 7b. Each frustum cone 20 has a virtual bottom surface 23 that is integral with the UV development reference plane 7b and is on the same plane as the UV development reference plane 7b. The frustum cone 20 has a conical shape in which the cross-sectional area parallel to the UV development reference plane 7b gradually decreases from the bottom surface 23 toward the top portion 22, and the degree of this decrease does not change. The central axis 20c of the frustum cone 20 is a line connecting a virtual vertex on the top portion 22 and the center of the bottom surface 23.

[0028] Note that, although the bottom surface 23 of each frustum 20 in the embodiment is circular, it may be elliptical. Also, the flat surface of the top portion 22 in the embodiment is circular and substantially parallel to the bottom surface 23, but it does not have to be parallel to the bottom surface 23. Furthermore, the top portion 22 may not be cut flat and may be in a sharp form, or may be formed in a spherical shape.

[0029] As shown in FIG. 7, the plurality of frustums 20 include three or more types with different angles θ1 of the central axis 20c with respect to the UV development reference plane 7b. Here, the angle θ1 is the angle on the acute angle side in each case. A plurality of frustums 20 with different angles θ1 of the central axis 20c are randomly arranged on the UV development reference plane 7b. Also, the inclination directions of the plurality of frustums 20, that is, the inclination directions of the central axis 20c, are not in a fixed direction but are inclined in random directions. Note that the angle θ1 of the central axis 20c on the acute angle side with respect to the UV development reference plane 7b is preferably, for example, about 30° or more and 80° or less.

[0030] As shown in FIG. 7, the plurality of frustums 20 include three or more types with different heights h from the UV development reference plane 7b. The height h here is the shortest distance from the UV development reference plane 7b to the top portion 22. Also, the plurality of frustums 20 include three or more types with different areas of their bottom surfaces 23. Also, the plurality of frustums 20 include three or more types with different apex angles θ2. The apex angle θ2 in this case refers to the angle at a virtual apex on the top portion 22. Note that the height h of the frustum 20 is preferably, for example, about 0.05 mm or more and 0.5 mm or less. Also, the area of the bottom surface 23 of the frustum 20 is, for example, 0.01 mm 2 or more 2 and 0.3 mm or less.

[0031] As shown in Fig. 7, some of the plurality of frustum cones 20 have an undercut shape including an acute-angle portion 27 where the side surface 21 contacts the UV development reference plane 7b at an acute angle. These acute-angle portions 27 may also contact the reference plane 7a of the pattern region 7 at an acute angle. The undercut shape refers to a shape having a portion that contacts the tire molding die 10 during mold opening when the tire 1 is vulcanized and molded by the tire molding die 10 described above. If it is an undercut shape of the size of the frustum cone 20 of the embodiment, mold opening is possible by elastic deformation of rubber.

[0032] Fig. 8 shows two specific frustum cones 20A and 20B shown in Figs. 3 and 4. Fig. 9 shows two specific frustum cones 20C and 20D shown in Figs. 3 and 4. Fig. 10 shows two specific frustum cones 20E and 20F shown in Figs. 3 and 4.

[0033] As shown in Fig. 8, the frustum cone 20A has a skirt portion 24a continuous with the UV development reference plane 7b, and the frustum cone 20B has a skirt portion 24b continuous with the UV development reference plane 7b. And these skirt portions 24a and 24b partially overlap each other. That is, the frustum cones 20A and 20B have a common overlap portion 25A where the skirt portions 24a and 23b overlap each other. In Fig. 8, the overlap portion 25A is shown by hatching.

[0034] As shown in Fig. 9, the frustum cone 20C has a skirt portion 24c continuous with the UV development reference plane 7b, and the frustum cone 20D has a skirt portion 24d continuous with the UV development reference plane 7b. And these skirt portions 24c and 24d partially overlap each other. That is, the frustum cones 20C and 20D have a common overlap portion 25B where the skirt portions 24c and 23d overlap each other. In Fig. 9, the overlap portion 25B is shown by hatching.

[0035] As shown in FIG. 10, the frustum 20E has a skirt portion 24e continuous with the UV development reference plane 7b, and the frustum 20F has a skirt portion 24f continuous with the UV development reference plane 7b. And these skirt portions 24e and 24f partially overlap each other. That is, the frustum 20E and the frustum 20F have a common overlap portion 25C where the skirt portions 24e and 23f overlap each other. In FIG. 10, the overlap portion 25C is shown hatched.

[0036] As described above, the plurality of frustums 20 have a plurality of overlap portions 25A, 25B, 25C where the skirt portions 24 of a pair of adjacent frustums 20 overlap each other. The overlap amounts of the respective overlap portions 25A, 25B, 25C are different from each other. That is, the plurality of frustums 20 include three or more overlap portions with different overlap amounts.

[0037] On the other hand, as shown in FIGS. 3, 4, and 7, the UV development reference plane 7b has a plurality of non-overlap portions 26 where the skirt portions 24 of a pair of adjacent frustums 20 do not overlap.

[0038] As shown in FIGS. 3 to 6, the plurality of frustums 20 are randomly arranged on the UV development reference plane 7b without taking a specific arrangement form, and their inclination directions and inclination angles along the central axis 20c are also random. However, the plurality of frustums 20 may be arranged on the UV development reference plane 7b in a certain arrangement form.

[0039] Figures 11 and 12 show an example of such a specific array form. In this case, a plurality of frustum cones 20 are linearly arranged along one direction, and the inclination directions are the same toward one direction. The flat tops 22 of the plurality of frustum cones 20 are flat surfaces orthogonal to the central axis. The plurality of frustum cones 20 have the same area of the top 22 and the same apex angle. That is, these frustum cones 20 have the same basic aspects such as their conical shapes and sizes except for the different inclination angles. The plurality of frustum cones 20 change such that the inclination angle of each central axis 20c gradually becomes steeper, that is, gradually becomes smaller, according to the order of their arrangement (the order from left to right in FIGS. 11 and 12). When the inclination angle gradually decreases in this way, the inclination angles of three or more frustum cones 20 may gradually decrease, or the inclination angles of four or more frustum cones 20 may gradually decrease.

[0040] In the plurality of frustum cones 20 shown in FIGS. 11 and 12, the leftmost frustum cone 20 has a central axis 20c perpendicular to the UV development reference plane 7b. That is, this frustum cone 20 can be said to be a straight cone. And as it goes toward the right, the frustum cone 20 falls to the right, and the degree of inclination increases as it goes toward the right. In the embodiment, at least one straight cone may be included among the plurality of frustum cones 20 in this way.

[0041] Each of the plurality of frustum cones 20 shown in FIGS. 3 to 6 and the plurality of frustum cones 20 shown in FIGS. 11 and 12 can be formed by the side plate 12 of the tire molding die 10 described above. As shown in FIGS. 13 and 14, the side plate 12 can include frustum cone forming portions 16 and 18 where the plurality of frustum cones 20 are formed.

[0042] Figure 13 shows a state in which a plurality of recesses 15 are formed in a UV development reference plane 12b when the inner surface 12a of the side plate 12 is UV-developed. Each of the plurality of recesses 15 is a conical recess corresponding to the shape and size of the plurality of frustum cones 20 shown in FIGS. 3 to 6, which are formed in the pattern region 7 after vulcanization, and is arranged at a position corresponding to the arrangement of the frustum cones 20. The frustum cone forming portion 16 includes these plurality of recesses 15.

[0043] Figure 14 shows a state in which a plurality of recesses 17 are formed in a UV development reference plane 12b when the inner surface 12a of the side plate 12 is UV-developed. Each of the plurality of recesses 17 is a conical recess corresponding to the shape and size of the plurality of frustum cones 20 shown in FIGS. 11 and 12, which are formed in the pattern region 7 after vulcanization, and is arranged at a position corresponding to the arrangement of the frustum cones 20. The frustum cone forming portion 18 includes the plurality of recesses 17 that form these plurality of frustum cones 20.

[0044] The method of forming the recesses 15 and the recesses 17 is not limited, but laser processing for irradiating the inner surface 12a of the side plate 12 with laser light to partially remove the inner surface 12a is suitable as the forming method. As the laser processing, for example, removal processing using a pulsed fiber laser can be adopted, and as the conditions of the laser processing, laser processing at a center wavelength of 1080 nm, an average output of 100 W or more and 300 W or less, and a laser spot diameter of about 0.05 mm is suitable.

[0045] According to the embodiment described above, the following effects can be obtained.

[0046] (1) The tire 1 according to the embodiment is a tire provided with a pattern region 7 provided in a visible state as a part different from the periphery of a part of the outer surface 3a of the sidewall 3, and when the reference plane 7a of the pattern region 7 is UV-developed, each of the plurality of frustum cones 20 is arranged in a state where its apex 22 is farthest from the UV development reference plane 7b.

[0047] The light incident on the pattern area 7 of the tire 1 is reflected by the side surface 21 of the frustum 20, and the reflected light is mainly reflected by the side surfaces 21 of a plurality of other frustums 20 around the frustum 20. Due to such light reflection occurring among the plurality of frustums 20, the light incident on the pattern area 7 gradually attenuates and is absorbed. When such a pattern area 7 is visually recognized, the pattern area 7 is visually recognized as darker than the outer surface 3a of the sidewall 3 that reflects the light around the pattern area 7. The frustum 20 is arranged with a plurality of frustums 20 having a conical shape, so that light reflection occurs complexly, whereby the pattern area 7 has a higher black density and higher contrast than before.

[0048] (2) In the tire 1 of the above (1) according to the embodiment, the plurality of frustums 20 have a central axis 20c connecting the apex of the frustum 20 and the center of the bottom surface 23, and it is preferable that the plurality of frustums 20 include three or more types with different angles of the central axis 20c with respect to the UV development reference plane 7b.

[0049] The plurality of frustums 20 of the embodiment have their central axes 20c inclined and not perpendicular to the UV development reference plane 7b. However, by including three or more types with different angles of the central axis 20c, at least three or more frustums 20 with different degrees of inclination are arranged in the pattern area 7. In this way, by arranging three or more frustums 20 with different degrees of inclination in the pattern area 7, the light incident on the pattern area 7 has more reflections between the frustums 20 or more diverse reflection angles, so that the light absorption effect further progresses. As a result, higher contrast with the improvement of black density is further achieved.

[0050] (3) In the tire 1 of the above (2) according to the embodiment, it is preferable that a plurality of frustums 20 with different angles of the central axis 20c with respect to the UV development reference plane 7b are randomly arranged on the UV development reference plane 7b.

[0051] As a result, the light incident on the pattern region 7 undergoes an increased number of reflections between the frustum cones 20 and diverse reflection angles, leading to a more advanced light absorption effect. Consequently, the high contrast achieved with an improved black density is further enhanced.

[0052] (4) In the tire 1 according to the above (2) or (3) embodiment, the plurality of frustum cones 20 are arranged along one direction, and along the order of the arrangement, each central axis 20c may be inclined and the inclination angle may gradually change.

[0053] As the inclination angles of the plurality of frustum cones 20 arranged in one direction gradually change in this way, the reflection angles of the light reflected between the adjacent frustum cones 20 do not remain constant but become complex, and the number of reflections of the light with respect to the reference plane 7a of the pattern region 7 also increases. As a result, the light absorption effect becomes more advanced, and consequently, the high contrast achieved with an improved black density is further enhanced. Note that when the inclination angle of the frustum cone 20 gradually decreases, the inclination angles of three or more frustum cones 20 may gradually decrease, or the inclination angles of four or more frustum cones 20 may gradually decrease.

[0054] (5) In the tire 1 according to the above (1) to (4) embodiment, it is preferable that the plurality of frustum cones 20 include three or more types having different heights h from the UV development reference plane 7b.

[0055] This can complicate the reflection of the light incident on the pattern region 7 between the frustum cones 20. As a result, the high contrast achieved with an improved black density is further enhanced.

[0056] (6) In the tire 1 according to the above (1) to (5) embodiment, it is preferable that the plurality of frustum cones 20 include three or more types having different bottom surface 23 areas.

[0057] This can complicate the reflection of the light incident on the pattern region 7 between the frustum cones 20. As a result, the high contrast achieved with an improved black density is further enhanced.

[0058] (7) In the tire 1 of the above (1) to (6) according to the embodiment, it is preferable that the plurality of frustum cones 20 include three or more types having different apex angles.

[0059] Thereby, the reflection between the frustum cones 20 of the light incident on the pattern area 7 can be complicated, and as a result, the contrast improvement accompanying the improvement of the black density can be further achieved.

[0060] (8) In the tire 1 of the above (1) to (7) according to the embodiment, the plurality of frustum cones have a skirt portion 24 continuous with the UV development reference plane 7b, and it is preferable that there are a plurality of overlapping portions where the skirt portions 24 of at least a pair of adjacent frustum cones 20 overlap each other.

[0061] By having a plurality of overlapping portions where the skirt portions 24 of the frustum cones 20 overlap each other, the density of the plurality of frustum cones 20 arranged in the pattern area 7 increases and the number increases. Thereby, the light absorption action of the light incident on the pattern area 7 becomes more advanced, and as a result, the contrast improvement accompanying the improvement of the black density can be further achieved.

[0062] (9) In the tire 1 of the above (8) according to the embodiment, it is preferable that the plurality of overlapping portions include three or more having different overlapping amounts.

[0063] Thereby, since the light reflection action by the plurality of frustum cones 20 arranged in the pattern area 7 is complicated, the light absorption action of the light incident on the pattern area 7 becomes more advanced, and as a result, the contrast improvement accompanying the improvement of the black density can be further achieved.

[0064] (10) In the tire 1 of the above (8) and (9) according to the embodiment, the UV development reference plane 7b has a non-overlapping portion where the skirt portions 24 of a pair of adjacent frustum cones 20 do not overlap.

[0065] As a result, a non-overlapping portion where the skirt portion 24 of the frustum 20 does not overlap is provided even on the reference surface 7a of the pattern region 7. Therefore, the light incident on the pattern region 7 is reflected not only between the plurality of frustums 20 but also at the non-overlapping portion. For this reason, in addition to between the frustums 20, light reflection also occurs between the frustum 20 and the non-overlapping portion, and the light absorption effect further progresses. As a result, the contrast improvement associated with the increase in black density is further achieved.

[0066] (11) In the tire 1 according to the above (1) to (10) embodiments, the plurality of frustums 20 have an undercut shape including an acute angle portion 27 where the surface of the side thereof is in acute contact with the reference surface 7a of the pattern region 7.

[0067] This makes it possible to complicate the reflection of the light incident on the pattern region 7 between the frustums 20. As a result, the contrast improvement associated with the increase in black density is further achieved.

[0068] (12) The tire molding die 10 according to the embodiment is a tire molding die for molding the tire 1 according to the above (1) to (11), and includes a frustum forming portion 16 including a plurality of recesses 15 corresponding to the plurality of frustums 20, and a frustum forming portion 18 including a plurality of recesses 17.

[0069] The plurality of recesses 15 and the recesses 17 included in the frustum forming portion 16 and the frustum forming portion 18 of the tire molding die 10 form a plurality of frustums 20 in the pattern region 7, by which the contrast improvement associated with the increase in black density is achieved. As a result, the tire 1 molded by the tire molding die 10 can improve the design effect and appearance.

[0070] As described above, the embodiments of the present invention have been described. However, the present invention is not limited to the above embodiments, and modifications, improvements, etc. can be made within the scope that can achieve the object of the present invention, and are included in the scope of the present invention.

[0071] For example, although the frustum 20 of the above embodiment has a conical shape, it may also have a polygonal pyramid shape. Further, the frustum 20 of the above embodiment has a conical shape in which the cross-sectional area parallel to the UV development reference plane 7b gradually decreases from the bottom surface 23 toward the top 22, and the degree of decrease does not change. However, it may also have a two-stage shape or a multi-stage shape with three or more stages in which the degree of decrease changes.

Explanation of Signs

[0072] 1 Tire 3 Sidewall 3a Outer surface of sidewall 7 Pattern area 7b UV development reference plane 10 Tire molding die 16, 18 Frustum forming part 20 Frustum 20c Central axis 23 Bottom surface of frustum 24 Skirt part 25A, 25B, 25C Overlap part 26 Non-overlap part 27 Acute angle part h Height of frustum θ1 Angle of central axis with respect to UV development reference plane θ2 Apex angle of frustum

Claims

1. A tire comprising a pattern area provided on a part of the outer surface of a sidewall in a visible state as a part different from the periphery of the part, wherein when the reference plane of the pattern area is UV-unfolded, each of a plurality of frustum cones is arranged such that its apex is farthest from the UV-unfolded reference plane.

2. The plurality of frustum cones have a central axis connecting the apex of the frustum cone and the center of the bottom surface, The tire according to claim 1, wherein the plurality of frustum cones include three or more types having different angles of the central axis with respect to the UV-unfolded reference plane.

3. The tire according to claim 2, wherein a plurality of the frustum cones having different angles of the central axis with respect to the UV-unfolded reference plane are randomly arranged on the UV-unfolded reference plane.

4. The tire according to claim 2 or 3, wherein the plurality of frustum cones are arranged along one direction, and according to the order of the arrangement, each central axis is inclined and the inclination angle gradually changes.

5. The tire according to claim 1 or 2, wherein the plurality of frustum cones include three or more types having different heights from the UV-unfolded reference plane.

6. The tire according to claim 1 or 2, wherein the plurality of frustum cones include three or more types having different bottom surface areas.

7. The tire according to claim 1 or 2, wherein the plurality of frustum cones include three or more types having different apex angles.

8. The tire according to claim 1 or 2, wherein the plurality of frustum cones have a skirt portion continuous with the UV-unfolded reference plane, and a plurality of overlapping portions are provided where the skirt portions of at least a pair of adjacent frustum cones overlap each other.

9. The tire according to claim 8, wherein the plurality of overlapping portions include three or more with different overlap amounts.

10. The tire according to claim 8, wherein the UV development reference plane has a non-overlapping portion where the skirt portions of the pair of adjacent frustum cones do not overlap.

11. The tire according to claim 1 or 2, wherein the plurality of frustum cones have an undercut shape including an acute angle portion where the side surface thereof contacts the reference plane of the pattern region at an acute angle.

12. A tire molding die for molding the tire according to claim 1 or 2, comprising a frustum cone forming portion including a plurality of recesses corresponding to the plurality of frustum cones.

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