Tire

Abstract

To provide a tire in which a black concentration increases more than before so that contrast can be enhanced.SOLUTION: A tire 1 comprises, on at least a portion of an external surface of a side wall 3 a patten region 7 visibly formed as a site different from a circumference of the portion. A plurality of recessed parts 110 whose side surfaces have quadrangular pyramid-shapes are tightly arranged in the pattern region 7. Light incident on the recessed parts 110 is repeatedly reflected and then is absorbed, so that the pattern region 7 further appears black.SELECTED DRAWING: Figure 3

Description

[Technical Field]

[0001] The present disclosure relates to a tire having a pattern area on at least a portion of the outer surface of the sidewall for displaying, for example, an insignia or a design. [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 by repeatedly reflecting incident light 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] JP 2017-1440 A Summary of the Invention [Problem to be solved by the invention]

[0004] High contrast achieved by a large number of protrusions has the advantage that it is less susceptible to deterioration over time than paint or other methods, and its effects are maintained for a long period of time. Therefore, there is a demand for the formation of pattern regions using protrusions that have a higher black density than before, leading to higher contrast and further improvements in design effects and appearance.

[0005] An object of the present disclosure is to provide a tire that has a higher black density than conventional tires and achieves higher contrast. [Means for solving the problem]

[0006] The tire disclosed herein is a tire having a pattern area on at least a portion of the outer surface of the sidewall, which is visibly different from the surrounding area of the portion, and in the pattern area, multiple convex or concave portions having a square-shaped side surface are arranged without any gaps. [Effects of the Invention]

[0007] According to the present disclosure, it is possible to provide a tire that has a 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 1 according to a first embodiment. [Figure 2] 1 is a diagram showing an example of a tire molding die for vulcanizing and molding a tire 1 according to an embodiment. [Figure 3] FIG. 2 is a perspective view showing a plurality of recesses 110 arranged in a pattern region 7. [Figure 4] 4 is a plan view showing a plurality of recesses 110 arranged in the pattern region 7, taken along the arrow T in FIG. 3. FIG. [Figure 5] 5 is a cross-sectional view of a plurality of recesses 110 arranged in the pattern region 7 taken along the position of the arrow AA in FIG. 4. FIG. [Figure 6] 5 is a cross-sectional view of a plurality of recesses 110 arranged in the pattern region 7 taken along the position of the arrow BB in FIG. 4. FIG. [Figure 7] FIG. 10 is a perspective view showing a pattern region 7B in the second embodiment, similar to FIG. 3 in the first embodiment. [Figure 8] 8 is a cross-sectional view of a plurality of convex portions 210 arranged in a pattern region 7B taken along the position of arrow CC in FIG. 7. FIG. DETAILED DESCRIPTION OF THE INVENTION

[0009] (First embodiment) Hereinafter, embodiments will be described with reference to the drawings. FIG. 1 is a side view of a tire 1 according to a first embodiment. The tire 1 is a so-called pneumatic tire whose inner cavity is filled with a predetermined air pressure. The tire 1 of the embodiment is a pneumatic tire for passenger cars including light cars 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.

[0010] First, an overview of the configuration of the tire 1, mainly related to its side surface, will be described with reference to FIG. 1. 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.

[0011] 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.

[0012] 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.

[0013] 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.

[0014] 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.

[0015] The tire 1 has a pattern area 7 provided in a part of the outer surface 3a of the sidewall 3 in a state where it is visibly different from the surrounding area of the part. The pattern area 7 is provided in the sidewall rubber, which is a black rubber member that forms the outer surface of the sidewall 3.

[0016] 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 a pattern region 7 of the embodiment.

[0017] 1, pattern portions 6B are provided in two locations in the annular decorative area 5, sandwiched between two emblem 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 a pattern area 7 of the embodiment.

[0018] The shape of the pattern area 7 is not limited to these, and various shapes can be used, such as any shape, or a shape depicting marks such as the manufacturer name, product name, brand, etc. mentioned above, or a shape depicting other numbers, letters, etc.

[0019] Each of the pattern regions 7 in the embodiment has a reference surface 7a that follows the profile of the sidewall 3. A plurality of recesses 110, which will be described later, are formed on this reference surface 7a. 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 surrounding area of the pattern region 7 by forming the plurality of recesses 110. Note that 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 in the same position as the profile of the sidewall 3 in the tire axial direction.

[0020] 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.

[0021] 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 (not shown). 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 bead rings 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 of the bead rings. During vulcanization molding, a bladder (not shown) is placed inside the unvulcanized tire 1a to press the unvulcanized tire 1a against the inner surface of the tire mold 10. The tread 4 is mainly formed by the plurality of sectors 11, and the sidewalls 3 are mainly formed by the pair of side plates 12. The bead 2 is formed by the pair of bead rings, and the entire inner surface of the tire 1 is formed by the bladder.

[0022] The tire molding mold 10 vulcanizes the unvulcanized tire 1a to form the rubber shape of the entire tire 1, and also forms a plurality of recesses 110, which will be described next, in the pattern region 7 described above.

[0023] FIG. 3 is a perspective view showing a plurality of recesses 110 arranged in the pattern region 7. FIG. 4 is a plan view showing a plurality of recesses 110 arranged in the pattern region 7, taken along the arrow T in FIG. 3. FIG. 5 is a cross-sectional view of a plurality of recesses 110 arranged in the pattern region 7, taken along the position of arrow AA in FIG. 4. FIG. 6 is a cross-sectional view of a plurality of recesses 110 arranged in the pattern region 7, taken along the position of arrow BB in FIG. 4. The plurality of recesses 110 are recessed from a reference surface 7a of the pattern region 7, and FIGS. 3 to 6 show a state in which the plurality of recesses 110 are recessed from a UV development reference surface 7b obtained by UV development of the reference surface 7a of the pattern region 7. The UV development reference surface 7b is a surface obtained by two-dimensionally developing the outer surface 3a of the three-dimensional sidewall 3.

[0024] The recess 110 has a rectangular side shape consisting of four side surfaces 111, 112, 113, and 114, and is recessed from the reference surface 7a (UV development reference surface 7b). That is, the recess 110 has a diamond-shaped opening corresponding to the bottom surface of the rectangular indentation, and is recessed axially inward, with the deepest part 115 being the part corresponding to the apex of the rectangular indentation. The four side surfaces 111, 112, 113, and 114 are all isosceles triangular.

[0025] The recesses 110 are arranged without gaps in the pattern region 7. That is, the recesses 110 are diamond-shaped openings corresponding to the bottom surfaces of the square indentations, and are closely packed in a two-dimensional regular pattern on the reference surface 7a. Note that "arranged without gaps" does not necessarily mean that the side surfaces of adjacent recesses 110 intersect at an acute angle, but refers to the recesses 110 being arranged so that there is no gap between them if the side surfaces of adjacent recesses 110 are extended as they are. Therefore, the ridge lines where the side surfaces of adjacent recesses 110 intersect, i.e., the ridge lines at the ends of the diamond-shaped openings corresponding to the bottom surfaces of the square indentations, may be slightly rounded or have a small flat portion. Furthermore, the corners where the side surfaces of the recesses 110 intersect do not need to be perfectly sharp, and may have a slightly rounded or chamfered inner surface.

[0026] A portion of the light incident on the recess 110 is reflected by the side surfaces 111, 112, 113, and 114 of the recess 110, and the reflected light is then reflected by the other side surfaces 111, 112, 113, and 114 around the recess 110 where the light was reflected. Due to this reflection of light occurring within the recess 110, the light incident on the recess 110 in the pattern region 7 is gradually attenuated and absorbed. Therefore, since a portion of the light incident on the pattern region 7 in which a plurality of recesses 110 are provided is absorbed and does not exit to the outside, when the recess 110 is visually observed, the pattern region 7 appears darker than the outer surface 3 a of the sidewall 3 that reflects the light around the pattern region 7.

[0027] 5 and 6, the maximum vertex spacing of the rectangular recesses 110 arranged adjacent to each other, i.e., the maximum vertex spacing among the spacings between the deepest portions 115 of the adjacent recesses 110, is defined as Pmax. Furthermore, the minimum vertex spacing among the spacings between the rectangular recesses 110 arranged adjacent to each other, i.e., the minimum vertex spacing among the spacings between the deepest portions 115 of the adjacent recesses 110, is defined as Pmin. Furthermore, the depth of the recesses 110 is defined as H. The maximum vertex spacing Pmax, the minimum vertex spacing Pmin, and the depth H can be set appropriately depending on the light absorption effect, durability of the recesses 110, ease of manufacture, and the like, as described above, but it is desirable to satisfy, for example, the following conditions:

[0028] 0.1mm≦Pmax≦0.2mm and, 0.2mm≦H≦0.4mm

[0029] By satisfying the above conditions, the light absorption effect can be fully exerted, and the durability of the pattern region 7 having the recesses 110 can be ensured, which facilitates the manufacture of the tire 1. Furthermore, if the above conditions are not satisfied, the light absorption effect cannot be fully exerted, the durability of the pattern region 7 having the recesses 110 may be poor, or dirt adhering to the pattern region 7 may be difficult to remove.

[0030] It is also more desirable to meet the following conditions:

[0031] H / Pmax≧1.0

[0032] By satisfying the relationship H / Pmax≧1.0, the angle formed between the side surfaces 111, 112, 113, 114 and the UV development reference surface 7b becomes smaller, that is, the angle formed between the side surfaces 111, 112, 113, 114 and the UV development reference surface 7b becomes closer to a right angle, thereby improving the light absorption effect.

[0033] Here, several examples and comparative examples of tires 1 with different recessed portion 110 shapes were prepared, and experiments were conducted to confirm the light absorption effect. The results are shown below. Six types of tires with different recessed portion 110 shapes were prepared as examples. As a comparative example without rectangular truncated recessed portions 110, a tire was prepared in which conventionally known uneven shapes also known as serrations were provided instead of the recessed portions 110. The serrations in this comparative example are formed by minute protrusions with a roughly triangular cross-sectional shape arranged in one direction to form a sawtooth shape, and extend in a direction perpendicular to the arrangement direction while maintaining the arrangement of the roughly triangular cross-sectional shape, i.e., the roughly sawtooth cross-sectional shape.

[0034] For the tires of the example and comparative example, the appearance of the pattern region 7 and the outer surface 3a of the sidewall 3 was compared, and the light absorption effect of the recesses 110 or the serrations of the comparative example was evaluated visually by sensory evaluation. The results are shown in the table below. The numerical values in the evaluation value column are on a scale of 1 to 5, with the higher the numerical value, the higher the light absorption effect and the darker the observed color. The evaluation value of 5 indicates the highest light absorption effect and is observed to be a so-called matte jet black. For evaluation values 1 to 4, the higher the numerical value, the darker the observed color.

[0035] Brightness was also measured as a measurement value indicating the degree of blackness, and the measurement results are also shown here. Brightness is expressed as a value from 0 to 100, with 0 being black and 100 being white. Brightness was measured using a color reader CR-20 manufactured by Konica Minolta Japan Inc., in accordance with JIS Z8781-4. The relationship between evaluation value and brightness is shown in Table 1 below.

[0036] [Table 1]

[0037] The results of evaluation and brightness measurement according to the above-mentioned evaluation criteria are shown in Table 2 below.

[0038] [Table 2]

[0039] Referring to the above experimental results, the Examples achieved a light absorption effect equal to or greater than that of the Comparative Examples. Furthermore, while the Comparative Examples sometimes exhibited a reduced light absorption effect depending on the observation direction, the Examples exhibited a stable light absorption effect regardless of the observation direction. Furthermore, among the Examples, the light absorption effect was high when the above-mentioned conditions, 0.1 mm≦Pmax≦0.2 mm and 0.2 mm≦H≦0.4 mm, were satisfied. Furthermore, the light absorption effect was high when H / Pmax≧1.0 was satisfied.

[0040] (Second embodiment) Fig. 7 is a perspective view showing a pattern region 7B in the second embodiment, similar to Fig. 3 of the first embodiment. Fig. 8 is a cross-sectional view of a plurality of convex portions 210 arranged in the pattern region 7B, cut at the position of the arrow CC in Fig. 7. The pattern region 7B in the second embodiment is similar to that in the first embodiment, except that convex portions 210 are provided instead of the concave portions 110 in the first embodiment. Therefore, parts that perform the same functions as those in the first embodiment described above are given the same reference numerals, and duplicate explanations will be omitted as appropriate.

[0041] The convex portions 210 of the second embodiment have a shape obtained by inverting the shape of the concave portions 110 of the first embodiment with respect to the UV development reference plane 7b. That is, the convex portions 210 of the second embodiment are formed by inverting the concave shape having a rectangular side surface of the concave portion 110 of the first embodiment with respect to the UV development reference plane 7b, and are formed as convex shapes having a rectangular side surface that protrude outward in the tire axial direction. In the pattern region 7B of the second embodiment, a plurality of convex portions 210 having the above-described rectangular side surface shape are arranged without any gaps.

[0042] Also in the second embodiment, a portion of light incident on the convex portion 210 is reflected by the side surfaces 211, 212, 213, and 214 of the convex portion 210 (the side surfaces 211 and 212 are not shown), and the reflected light is then reflected by the other side surfaces 211, 212, 213, and 214 around the recessed portion 110 where the light was reflected. Such reflection of light occurs between the convex portions 210, so that the light incident on the convex portions 210 in the pattern region 7 is gradually attenuated and absorbed. Therefore, since a portion of the light incident on the pattern region 7 in which a plurality of convex portions 210 are provided is absorbed and does not exit to the outside, when the convex portions 210 are visually observed, the pattern region 7 appears darker than the outer surface 3 a of the sidewall 3 that reflects the light around the pattern region 7.

[0043] Also, in the second embodiment, similarly to the first embodiment, it is desirable to satisfy, for example, the following conditions: In the second embodiment, H is the height of the convex portion 210, and the maximum vertex spacing among the spacings between the vertices 215 is Pmax.

[0044] 0.1mm≦Pmax≦0.2mm and, 0.2mm≦H≦0.4mm

[0045] It is also more desirable to meet the following conditions: H / Pmax≧1.0

[0046] The reasons why it is desirable to satisfy each of the conditions are the same as those in the first embodiment.

[0047] The tire 1 according to the first or second embodiment described above provides the following effects.

[0048] (1) The tire 1 of this embodiment is a tire 1 having a pattern region 7 provided on at least a portion of the outer surface of the sidewall 3 in a state that is visibly different from the surrounding area of the portion, and the pattern region 7 has multiple convex portions 120 or concave portions 110 with a square-shaped side surface shape arranged without any gaps.

[0049] This makes it possible to effectively absorb light incident on the pattern region 7, and to provide a tire with a higher black density and higher contrast than conventional tires.

[0050] (2) In the tire 1 described in (1), when the maximum vertex distance among the vertex distances of the rectangular grooves of adjacently arranged convex portions 210 or concave portions 110 is Pmax and the height or depth of the convex portion 210 or concave portion 110 is H, the tire satisfies the relationships 0.1 mm≦Pmax≦0.2 mm and 0.2 mm≦H≦0.4 mm.

[0051] This allows the pattern region 7 to fully absorb the light incident thereon, ensures the durability of the pattern region 7, and facilitates the manufacture of the tire 1. Furthermore, it also makes it easier to remove dirt adhering to the pattern region 7.

[0052] (3) In the tire 1 described in (1) or (2), when the maximum vertex distance among the vertex distances of the rectangular grooves of adjacently arranged convex portions 210 or concave portions 110 is Pmax and the height or depth of the convex portion 210 or concave portion 110 is H, the tire satisfies the relationship H / Pmax≧1.0.

[0053] This can enhance the light absorption effect.

[0054] (Variations) The present disclosure is not limited to the above-described embodiments, and various modifications and variations are possible, and these are also within the scope of the present disclosure.

[0055] (Variation 1) In each embodiment, the recess 110 or the protrusion 210 has Pmax≧Pmin, and the part corresponding to the bottom surface of the rectangular protrusion (the opening of the recess 110 or the base of the protrusion 210) has a diamond shape in plan view. However, the present invention is not limited to this. For example, the recess 110 may have a regular rectangular protrusion shape in which Pmax=Pmin, that is, the part corresponding to the bottom surface of the rectangular protrusion has a square shape.

[0056] (Modification 2) In each embodiment, an example has been described in which the recessed portion 110 or the protruding portion 210 is recessed or protruding with respect to the reference plane 7a (UV development reference plane 7b) along the profile of the sidewall 3. However, the present invention is not limited to this, and for example, the reference plane 7a of the recessed portion 110 or the protruding portion 210 may be protruding axially outward from the profile of the sidewall 3, or may be recessed axially inward from the profile of the sidewall 3.

[0057] The embodiments and modifications may be used in combination as appropriate, but detailed description thereof will be omitted. The present disclosure is not limited to the embodiments described above. [Explanation of symbols]

[0058] 1 tire 1a Unvulcanized tires 1s side 2 beads 3 Sidewall 3a outer surface 4 Tread 5. Decoration Area 5a Inner arc line 5b Outer arc line 6A Mark section 6B Pattern section 7 Pattern Area 7B Pattern area 7a Reference plane 7b UV development reference plane 10 Tire molding mold 11 sectors 11a Inner surface 12 Side Plate 12a Inner surface 110 recess 111~114 Side 115 Deepest Depths 120 convex part 210 Convex 211~214 Side 215 Vertex

Claims

1. A tire having a pattern area provided on at least a portion of the outer surface of a sidewall in a state where it is visible as a part different from the surrounding area of the part, In the pattern region, a plurality of convex or concave portions each having a square-shaped side surface are arranged without any gaps.

2. 2. The tire according to claim 1, When the maximum vertex distance among the vertex distances of the adjacently arranged convex portions or concave portions is defined as Pmax and the height or depth of the convex portion or the concave portion is defined as H, 0.1mm≦Pmax≦0.2mm and, 0.2mm≦H≦0.4mm Satisfying the relationship, tire.

3. The tire according to claim 1 or 2, When the maximum vertex distance among the vertex distances of the adjacently arranged convex portions or concave portions is defined as Pmax and the height or depth of the convex portion or the concave portion is defined as H, H / Pmax≧1.0 Satisfying the relationship, tire.

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