Tire

Abstract

To provide a tire having a higher black density and a higher contrast than a conventional tire.SOLUTION: A tire 1 includes, in a part of an external surface 3a of a sidewall 3, a pattern region 7 visibly provided as a portion different from a periphery of the part. In the pattern region 7, a plurality of protrusion groups (100, 200) each of which is composed of a plurality of protrusions 110 are arranged. Each of the protrusion groups (100, 200) includes: a first protrusion group 100 composing a repeating unit repeatedly arranged in the pattern region 7; and a second protrusion group 200 having an excluded portion (220, 230) in which at least a part of a shape of a protrusion is excluded in some of the plurality of protrusions 110 composing the first protrusion group 100.SELECTED DRAWING: Figure 3

Description

Technical Field

[0001] The present disclosure relates to a tire having a pattern area for displaying, for example, a logo or a pattern on a part of the outer surface of the sidewall.

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 the 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. As a result, 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 exhibited over a long period of time. Therefore, there has been a demand for the formation of a pattern area by protrusions that has a higher black density and further improves the high contrast and further improves the design effect and appearance than in the past.

[0005] An object of the present disclosure is to provide a tire in which the black density is increased and high contrast is achieved as compared with the conventional one.

Means for Solving the Problems

[0006] The tire of the present disclosure is a tire provided with a pattern area provided in a visible state as a part different from the periphery on a part of the outer surface of the sidewall, and a plurality of protrusion groups composed of a plurality of protrusions are arranged in the pattern area. The protrusion group includes a first protrusion group that constitutes a repeating unit repeatedly arranged in the pattern area, and a second protrusion group having an exclusion site excluding at least a part of the shape of the protrusion for a part of the plurality of protrusions constituting the first protrusion group.

Advantages of the Invention

[0007] According to the present disclosure, it is possible to provide a tire in which the black density is increased and a high contrast is achieved as compared with the prior art.

Brief Description of the Drawings

[0008]

Figure 1

Figure 2

Figure 3

Figure 4

Figure 5

Modes for Carrying Out the Invention

[0009] 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, SUVs, etc. 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, 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. Note that the tire axial direction, the tire circumferential direction, and the tire radial direction referred to in the following description 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 is the left-right direction when viewed from the tire radial direction, the tire axial direction may be referred to as the left-right direction. 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 and is arbitrarily indicated by an arrow Y in FIG. 1.

[0011] 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 includes one on each side of the one side surface 1s of the tire 1 shown in FIG. 1 and the other side surface not shown in FIG. 1 that is separated in the tire axial direction, that is, a left-right pair. 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.

[0012] 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. On the inner cavity side of the rubber that constitutes the entire tire 1, a carcass ply that constitutes the skeleton of the tire 1 is arranged. Further, on the inner cavity side of the carcass ply, an inner liner for holding air pressure is arranged. Also, 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 the figure). In addition to these members, various members are provided as required for the functions of the tire 1.

[0013] As shown in FIG. 1, the sidewall 3 has an annular decorative region 5 on its outer surface 3a that extends 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, which is closer 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 recesses, protrusions, or steps, or may be virtual lines that do not actually exist.

[0014] The position of the decorative region 5 in the tire radial direction 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. Note that the maximum tire width position refers to the position where the length in the tire axial direction is the longest between the outer surfaces 3a of the left and right sidewalls 3.

[0015] The tire 1 includes a pattern region 7 provided in a visible state as a part different from the surrounding part on a part of the outer surface 3a of the sidewall 3. The pattern region 7 is provided on the sidewall rubber, which is a black rubber member that constitutes the outer surface of the sidewall 3.

[0016] As shown in Fig. 1, at two locations on the annular decorative region 5 that face each other across the tire rotation axis X, there are provided logo portions 6A. The logo portions 6A are formed by arranging a plurality of characters in the tire circumferential direction. At least one of logos 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 bordered by a concave or convex line, or the entire character may be formed in a concave or convex shape. For example, each character of the logo portion 6A is provided as the pattern region 7 of the embodiment.

[0017] As shown in Fig. 1, in the annular decorative region 5, at two locations sandwiched between two logo portions 6A in the circumferential direction, there are provided pattern portions 6B. The pattern portions 6B are provided with a pattern such that a parallelogram is curved following the annular decorative region 5. For example, each pattern of the pattern portion 6B is also provided as the pattern region 7 of the embodiment.

[0018] Note that the shape of the pattern region 7 is not limited to these, and various shapes can be mentioned, such as an arbitrary shape, or a shape depicting a logo such as the manufacturer name, product name, brand, etc. described above, or a shape depicting other numbers, characters, etc.

[0019] Each of the above pattern regions 7 in the embodiment has a reference plane 7a along the profile of the sidewall 3. A plurality of protrusions 110 described later are formed on this reference plane 7a. The pattern region 7 is a region provided in a visually recognizable state as a part different from the periphery of the pattern region 7 by forming a plurality of protrusions 110.

[0020] 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.

[0021] 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 disposed 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 disposed 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.

[0022] 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 first protrusion groups 100 and second protrusion groups 200 described below are formed in the above-mentioned pattern region 7.

[0023] Fig. 3 is a perspective view showing a plurality of first protrusion groups 100 and second protrusion groups 200 arranged in the pattern region 7. Fig. 4 is a plan view showing a plurality of first protrusion groups 100 and second protrusion groups 200 arranged in the pattern region 7 and is a view taken in the direction of arrow T in Fig. 3. Fig. 5 is a side view showing a plurality of first protrusion groups 100 and second protrusion groups 200 arranged in the pattern region 7 and is a view taken in the direction of arrow S in Fig. 3.

[0024] The pattern region 7 has a plurality of arranged groups of protrusions composed of a plurality of protrusions 110. Specifically, as the groups of protrusions, a first protrusion group 100 and a second protrusion group 200 are arranged.

[0025] The first protrusion group 100 is composed of a plurality of protrusions 110 regularly arranged, which constitutes a repeating unit repeatedly arranged in the pattern region 7. In one first protrusion group 100 of the present embodiment, the protrusions 110 are arranged in a 3×3 square lattice. The protrusion 110 of the present embodiment has a substantially cylindrical shape and protrudes from the UV development reference plane 7b. More specifically, the protrusion 110 of the present embodiment has a cylindrical portion 110a on the root side, a top portion 110b parallel to the UV development reference plane 7b, and a ridge portion 110c with a rounded corner provided on the ridge line between the cylindrical portion 110a and the top portion 110b.

[0026] A part of the light incident on the first protrusion group 100 is reflected on the side surface of the protrusion 110, and the reflected light is reflected on the side surfaces of a plurality of other protrusions 110 around the reflected protrusion 110. Due to such light reflection occurring among the plurality of protrusions 110, the light incident on the first protrusion group 100 in the pattern region 7 gradually attenuates and is absorbed. Therefore, since a part of the light incident on the first protrusion group 100 is absorbed and does not exit to the outside, when the first protrusion group 100 is visually recognized, it is visually recognized as darker than the outer surface 3a of the side wall 3 that reflects the light around the pattern region 7. Regarding the height H of the protrusion 110 and the pitch P (the center-to-center distance between adjacent protrusions 110) shown in FIG. 5, they can be appropriately set according to the above-described light absorption effect, durability of the protrusion 110, ease of manufacturing, etc. For example, the height H of the protrusion 110 can be 150 μm or more and 700 μm or less. Also, for example, the pitch P at which the protrusions 110 are arranged is preferably about 80% to 200% where the bases slightly overlap with respect to the diameter of the cylindrical portion on the root side of the protrusion 110, and 150 μm or more and 1500 μm or less can be exemplified. Furthermore, it is more preferable that the protrusion height H and the pitch P satisfy the relationship of P < 1.5H in order to effectively obtain the effects of light reflection and attenuation.

[0027] The second protrusion group 200 includes a plurality of protrusions 110 having the same shape as the plurality of protrusions 110 that make up the first protrusion group 100. The second protrusion group 200 also has exclusion sites 220 and 230 that exclude at least a part of the shape of the protrusion 110 for some of the plurality of protrusions 110 that make up the first protrusion group 100. The second protrusion group 200 is configured such that at least one of these protrusions 110 and the exclusion sites 220 and 230 is arranged in the same manner as the arrangement of the protrusions 110 in the first protrusion group 100.

[0028] In FIGS. 3 to 5, as an example of the second protrusion group 200, the form of the exclusion site 220 provided as a protrusion having a lower height than the protrusions 110 provided at positions other than the position corresponding to the exclusion site 220 in the first protrusion group 100 is shown. The height of the exclusion site 220 is preferably half or less of the height H of the protrusion 110. Also, in FIGS. 3 to 5, as another example of the second protrusion group 200, the form of the exclusion site 230 without a protrusion is shown. Note that in FIGS. 3 to 5, an example in which only one exclusion site 220 (or exclusion site 230) is provided in one second protrusion group 200 is illustrated, but a plurality of exclusion sites may be provided in one second protrusion group 200. Also, the exclusion site 220 and the exclusion site 230 may be mixed in one second protrusion group 200. Also, an example in which the tip of the exclusion site 220 provided as a protrusion with a lower height is a flat surface substantially parallel to the UV development reference plane 7b is illustrated. However, for example, the tip of the exclusion site 220 may be an inclined surface inclined with respect to the UV development reference plane 7b, or may have a tapered shape on the tip side, and the tip shape may be any shape.

[0029] Also in the second protrusion group 200, similar to the first protrusion group 100, the light incident on the second protrusion group 200 in the pattern region 7 by the protrusions 110 is gradually attenuated and absorbed. Therefore, since a part of the light incident on the second protrusion group 200 is absorbed and does not exit to the outside, when the second protrusion group 200 is visually recognized, it is visually recognized as darker than the outer surface 3a of the sidewall 3 that reflects the light around the pattern region 7.

[0030] In addition, at least one of an exclusion site 220 and an exclusion site 230 is provided in the second protrusion group 200. Due to the presence of these exclusion site 220 and exclusion site 230, the light reflection path is not uniform and becomes more complex, so that the light absorption effect can be exerted for light at more incident angles than the first protrusion group 100. Therefore, compared with the case where only the first protrusion group 100 is provided, in the pattern region 7 of the present embodiment including the second protrusion group 200, the effect of being visually recognized as blacker than the outer surface 3a of the side wall 3 that reflects the light around the pattern region 7 is further enhanced, and the black density is increased and high contrast can be achieved as compared with the conventional case. In addition, when only the first protrusion group 100 is uniformly provided, the occurrence of moire is increased and there is a high possibility that a stripe pattern is observed in the pattern region 7, but in the pattern region 7 of the present embodiment including the second protrusion group 200, the occurrence of moire can be suppressed.

[0031] As a method for manufacturing the tire 1 having the first protrusion group 100 and the second protrusion group 200, it can be performed by processing a mold (for example, the tire molding mold 10 described above) using laser processing. That is, by laser processing, recess processing corresponding to the first protrusion group 100 and recess processing corresponding to the second protrusion group 200 are performed on the mold used for molding the tire 1. By molding the tire 1 using the mold subjected to this recess processing, the tire 1 having the pattern region 7 of the present disclosure can be manufactured.

[0032] As the laser processing, for example, removal processing using a pulsed fiber laser can be adopted, and as the conditions for 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 preferable.

[0033] Also, as a specific example of a method for forming a recess on the inner surface of the side plate 12, in which a first protrusion group 100 and a second protrusion group 200 including exclusion sites 220, 230, etc. are formed, the following method can be cited. A recess that does not include a portion where the exclusion sites 220, 230, etc. can be formed is formed by, for example, laser processing as described above. Then, an organic substance such as resin or an inorganic substance such as metal is partially filled into the recess by means such as spraying. Next, a part of the filler is partially removed by means such as sandblasting in which metal powder such as alumina or glass beads is projected by high-pressure air. Thereby, the filler is formed into a desired shape and dimensions according to the exclusion sites 220, 230, etc. After that, when the tire 1 is vulcanized and molded using the tire molding die 10, a shape corresponding to the protrusion 110 is formed in the recess, and the filler serves as a carcass and the exclusion sites 220, 230, etc. are formed. According to this processing method, it is possible to easily obtain the first protrusion group 100 and the second protrusion group 200 having a desired shape or a complicated shape of the protrusion 110, exclusion sites 220, 230, etc., without taking the trouble of generating complicated processing data and processing based on it. Further, from the viewpoint of enhancing the mold release property from rubber, the filler is preferably formed with a surface area of 10% or more and 50% or less of the surface area of the belt-like convex portion. Note that the manufacturing method of the tire 1 having the first protrusion group 100 and the second protrusion group 200 is not limited to the method exemplified above.

[0034] In addition, in the present embodiment, a gap region 300 where no protrusion 110 is provided is provided between the first protrusion group 100 and the second protrusion group 200. More specifically, as shown in FIGS. 4 and 5, the gap G2 between the first protrusion group 100 and the second protrusion group 200 (the width of the gap region 300) is wider than the protrusion gap G1 between the adjacent protrusions 110 in the first protrusion group 100 and the second protrusion group 200. Thereby, the occurrence of moiré can be suppressed. Note that the present invention is not limited to the form in which the gap region 300 is provided. For example, the gap region 300 may not be provided, and the first protrusion group 100 and the second protrusion group 200 may be continuously arranged, that is, the protrusions 110 of the first protrusion group 100 and the protrusions 110 of the second protrusion group 200 may be arranged side by side at a pitch P at which the protrusions 110 are arranged. Further, the gap G2 between the protrusion groups may be made narrower than the protrusion gap G1. More preferably, the gap G2 between the protrusion groups is irregularly set to about 70% to 150% of the protrusion gap G1, for example. By such an irregular setting, the occurrence of moiré can be suppressed more effectively, and a high-contrast surface can be obtained.

[0035] According to the tire 1 according to the above-described present embodiment, the following effects can be obtained.

[0036] (1) The tire 1 according to the present embodiment is a tire 1 including a pattern region 7 provided in a visible state as a part different from a part of the outer surface 3a of the sidewall 3, and a plurality of protrusion groups (100, 200) formed by a plurality of protrusions 110 are arranged in the pattern region 7. The protrusion groups (100, 200) include a first protrusion group 100 that constitutes a repeating unit repeatedly arranged in the pattern region 7, and a second protrusion group 200 having an exclusion part (220, 230) in which at least a part of the shape of the protrusion is excluded for a part of the plurality of protrusions 110 that constitute the first protrusion group 100.

[0037] Thereby, the black density can be increased more than before, and high contrast can be achieved. In addition, the occurrence of moiré in the pattern region 7 can be suppressed.

[0038] The tire 1 according to (2)(1), wherein the protrusions 110 are regularly arranged except for the excluded portions (220, 230).

[0039] Thereby, the appearance of the pattern region 7 can be made uniform.

[0040] The tire 1 according to (3)(1) or (2), wherein the excluded portion 230 does not include the protrusion 110.

[0041] Thereby, the formation of the excluded portion 230 can be easily performed.

[0042] The tire 1 according to (4)(1) or (2), wherein the excluded portion 220 is provided with a protrusion having a height lower than that of the protrusion 110 provided at a position other than the position corresponding to the excluded portion 220 in the first protrusion group 100.

[0043] Thereby, the excluded portion 220 can be made inconspicuous, and the effect of the excluded portion 220 can be adjusted by the height of the excluded portion 220.

[0044] The tire 1 according to (5)(1) or (2), wherein the first protrusion group 100 and the second protrusion group 200 are arranged with a space therebetween.

[0045] Thereby, the distinction between the first protrusion group 100 and the second protrusion group 200 can be easily made.

[0046] The tire 1 according to (6)(2), wherein the protrusion group interval G2 between the first protrusion group 100 and the second protrusion group 200 arranged adjacent to each other is different from the protrusion interval G1 between the protrusions 110 arranged adjacent to each other in the first protrusion group 100 and the second protrusion group 200.

[0047] Thereby, the occurrence of moiré can be suppressed.

[0048] (Deformable form) Without being limited to the embodiments described above, various modifications and changes are possible, and they are also within the scope of this disclosure.

[0049] (Deformable form 1) In the embodiment, an example in which the shape of the protrusion 110 is a cylindrical shape having a top portion 110b and a ridgeline portion 110c with rounded edges has been described. However, it is not limited to this. For example, the shape of the protrusion 110 may have a hemispherical tip, or the ridgeline portion 110c may not have a rounded edge. Further, the shape of the protrusion 110 is not limited to a cylindrical shape. For example, it may be a substantially frustum-shaped cone having a conical side surface and a flat top portion. Also, it may be a shape protruding in a polygonal shape such as a triangular prism, a triangular pyramid, a quadrangular prism, or a quadrangular pyramid. In this case, a form protruding in a polygonal shape with a larger number of corners (for example, a hexagon or an octagon) is desirable for making the pattern region 7 appear darker.

[0050] (Deformable form 2) In the embodiment, an example in which the protrusions 110 are arranged in a 3×3 square lattice in one first protrusion group 100 has been described. However, it is not limited to this. The arrangement of the protrusions in the first protrusion group can be changed as appropriate. For example, the protrusions may be arranged in a square lattice such as 4×4 or 5×5. Also, the arrangement of the protrusions is not limited to a square lattice. For example, it may be arranged in a staggered lattice.

Explanation of reference numerals

[0051] 1 Tire 1a Unvulcanized tire 1s Side surface 2 Bead 3 Sidewall 3a Outer surface 4 Tread 5 Decoration area 5a Inner arc line 5b Outer arc line 6A Emblem part 6B Pattern part 7 Pattern area 7a Reference plane 7b UV development reference plane 10 Tire molding die 11 sectors 11a inner surface 12 side plates 12a inner surface 100 first protrusion group 110 protrusion 110a cylindrical part 110b top part 110c ridgeline part 200 second protrusion group 220, 230 excluded parts 300 gap region

Claims

1. A tire comprising a pattern region 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 a plurality of groups of protrusions each composed of a plurality of protrusions are arranged in the pattern region, and the groups of protrusions include a first group of protrusions constituting a repeating unit repeatedly arranged in the pattern region, and a second group of protrusions having an excluded part obtained by excluding at least a part of the shape of the protrusions from a part of the plurality of protrusions constituting the first group of protrusions. The tire according to claim 1, comprising the above.

2. In the tire according to claim 1, the protrusions are regularly arranged except for the excluded part. The tire is characterized by the above.

3. In the tire according to claim 1 or claim 2, the excluded part does not include the protrusions. The tire is characterized by the above.

4. In the tire according to claim 1 or claim 2, the excluded part is provided with a protrusion having a lower height than the protrusions provided at positions other than the position corresponding to the excluded part in the first group of protrusions. The tire is characterized by the above.

5. In the tire according to claim 1 or claim 2, the first group of protrusions and the second group of protrusions are arranged with a space therebetween. The tire is characterized by the above.

6. In the tire according to claim 2, the interval between the groups of protrusions between the adjacent first and second groups of protrusions is different from the interval between the adjacent protrusions in the first and second groups of protrusions. The tire is characterized by the above.

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