Tire

Abstract

Provided is a tire which has a higher black density than conventional tires, can achieve a higher contrast ratio, and has good moldability. A tire (1) is provided with a pattern region (7) in at least a portion of the outer surface of a sidewall (3), the pattern region being provided in a state of being visible as a different site from the periphery of the portion, the pattern region (7) being provided with a plurality of protrusions (110) protruding from a reference surface (7a), the protrusions (110) having: a recess (111) having an inverted conical or inverted pyramidal inner surface; a tapered main body section (112) that forms the outer periphery of the protrusion (110) and that extends in a tapered shape from the reference surface (7a) in the direction in which the protrusion (110) protrudes; and an outer edge portion (113) surrounding the periphery of the recess portion (111), the protrusion height of the protrusion (110) being 0.6 mm or more and 1.4 mm or less, and the depth of the recess portion (111) being 30% or more and 70% or less of the protrusion height of the protrusion (110).

Description

Technical Field

[0001] The present disclosure relates to a tire including a pattern region for displaying, for example, a logo, a pattern, or the like, on at least a portion of an outer surface of a sidewall. Background Art

[0002] Tires are known to have a patterned area composed of a collection of fine protrusions on a portion of their sidewalls (e.g., Patent Document 1). This patterned area absorbs incident light by repeatedly reflecting it between the protrusions, making it appear darker than the surrounding sidewall surface, improving contrast. By including this patterned area, tires can achieve improved design and aesthetics, for example.

[0003] Prior art literature

[0004] Patent Literature

[0005] Patent Document 1: Japanese Patent Application Laid-Open No. 2020-131904 Summary of the Invention

[0006] Problems to be solved by the invention

[0007] However, in the tire disclosed in Patent Document 1, micro protrusions are arranged in a grid-like portion surrounded by rib-like protrusions, resulting in a complex structure and high manufacturing difficulty. Therefore, it may not be formed into a desired shape, and the appearance may be deteriorated.

[0008] An object of the present disclosure is to provide a tire having a higher black density than conventional tires to achieve a higher contrast and having good formability.

[0009] Means for solving problems

[0010] The pneumatic tire disclosed herein has a pattern area on at least a portion of the outer surface of the sidewall, and the pattern area is arranged to be visually recognizable as a portion different from the surrounding area of ​​the portion, wherein a plurality of protrusions protruding from a reference plane are provided in the pattern area, and the protrusions have: a recess having an inverted conical or inverted pyramidal inner surface; a conical main body forming the outer periphery of the protrusion and extending in a conical shape from the reference plane in a direction in which the protrusion protrudes; and an outer edge portion surrounding the recess, the protrusion having a protruding height of 0.6 mm or more and 1.4 mm or less, and a depth of the recess being 30% or more and 70% or less of the protruding height of the protrusion.

[0011] Effects of the Invention

[0012] According to the present disclosure, it is possible to provide a tire that has a higher black density than conventional tires, thereby achieving higher contrast and having excellent formability. BRIEF DESCRIPTION OF THE DRAWINGS

[0013] Figure 1 It is a side view of the tire 1 according to the first embodiment.

[0014] Figure 2 An example of a tire forming mold for vulcanization-molding the tire 1 according to the embodiment is shown.

[0015] Figure 3 It is a perspective view showing a plurality of protrusions 110 arranged in the pattern region 7 .

[0016] Figure 4 is a top view showing a plurality of protrusions 110 arranged in the pattern area 7. Figure 3 T-direction view.

[0017] Figure 5 is Figure 4 A cross-sectional view of the plurality of protrusions 110 arranged in the pattern region 7 taken along the arrow AA in FIG.

[0018] Figure 6 It is a cross-sectional view showing an example in which the outer edge portion 113 is configured as a flat surface.

[0019] Figure 7 is a table summarizing the experimental results.

[0020] Description of reference numerals:

[0021] 1 tire

[0022] 1a Unvulcanized tire

[0023] 1s side

[0024] 2 tire beads

[0025] 3 Sidewall

[0026] 3a External surface

[0027] 4 tread

[0028] 5 Decoration area

[0029] 5a Inside Arc

[0030] 5b Outer arc

[0031] 6A Mark Department

[0032] 6B pattern part

[0033] 7 Pattern Area

[0034] 7a Datum plane

[0035] 7b UV unfolding base plane

[0036] 10 Tire forming mold

[0037] 11 Fan-shaped mold

[0038] 11a Inner surface

[0039] 12 side panels

[0040] 12a Inner surface

[0041] 110 protrusion

[0042] 111 recess

[0043] 112 cone-shaped main body

[0044] 113 outer edge. DETAILED DESCRIPTION

[0045] Hereinafter, one embodiment for implementing the present disclosure will be described with reference to the drawings and the like.

[0046] Hereinafter, embodiments will be described with reference to the drawings. Figure 1 This is a side view of a tire 1 according to a first embodiment. Tire 1 is a so-called pneumatic tire whose inner cavity is filled with air at a predetermined pressure. Tire 1 according to this embodiment is a pneumatic tire for passenger vehicles, including light cars and SUVs. It should be noted that the structure of tire 1 according to this embodiment can also be applied to pneumatic tires for other types of vehicles, such as light trucks, trucks, and buses.

[0047] First, refer to Figure 1 The outline of the structure of the tire 1 mainly related to the side faces will be described. Figure 1 This is a side view of the tire 1 viewed from the direction of the tire rotation axis X. It should be noted that the tire axial direction, tire circumferential direction, and tire radial direction mentioned in the following description are as follows. The tire axial direction refers to the extension direction of the tire rotation axis X. Figure 1 The center refers to the front and back direction of the paper. It should be noted that when viewed from the tire radial direction, the tire axial direction is the left and right direction, so the tire axial direction is sometimes referred to as the left and right direction. The tire circumferential direction refers to the arc line centered on the tire rotation axis X, which is the direction along the rotation direction of the tire 1. Figure 1 Indicated by arrow G. The tire radial direction refers to the direction perpendicular to the tire rotation axis X. Figure 1 It is arbitrarily indicated by arrow Y.

[0048] like Figure 1 As shown, the tire 1 includes a bead 2, a sidewall 3 extending from the bead 2 in the tire radial direction toward the outer side away from the tire rotation axis X, and a tread 4. The bead 2 and the sidewall 3 are respectively Figure 1The side 1s of the tire 1 shown is separated from the side 1s of the tire 1 in the axial direction. Figure 1 The other side surface (not shown) is provided with one on each side, that is, a pair of left and right treads. The tread 4 is arranged between the radially outer sides of the left and right sidewalls 3. The outer peripheral surface of the tread 4 includes a tread surface that contacts the road surface.

[0049] The tire 1 is primarily constructed from a variety of rubber components, comprising the beads 2, sidewalls 3, and tread 4. A carcass ply, forming the tire's skeleton, is positioned within the inner cavity of the rubber that makes up the tire 1. Furthermore, an inner liner, which maintains air pressure, is positioned within the inner cavity of the carcass ply. Furthermore, an annular reinforcing belt is embedded within the rubber that makes up the tread 4 (the carcass ply, inner liner, and reinforcing belt are not shown). It should be noted that in addition to these components, various other components are provided as necessary to ensure the functionality of the tire 1.

[0050] like Figure 1 As shown, the sidewall 3 has an annular decorative region 5 on its outer surface 3a extending throughout the entire circumference of the tire. The decorative region 5 is a region of constant width sandwiched between an inner arc line 5a located radially inward and closer to the tire's rotation axis X, and an outer arc line 5b located radially outward of 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.

[0051] The decorative area 5 on the outer surface 3a of the sidewall 3 may be positioned radially outward from the maximum tire width, or may be positioned within the maximum tire width. It should be noted that the maximum tire width refers to the position where the tire axial length is greatest between the outer surfaces 3a of the left and right sidewalls 3.

[0052] The tire 1 includes a pattern region 7 on a portion of the outer surface 3a of the sidewall 3. The pattern region 7 is provided in the sidewall rubber, which is a black rubber member constituting the outer surface of the sidewall 3.

[0053] like Figure 1 As shown, insignia portions 6A are provided at two locations of the annular decorative region 5, opposite each other across the tire's rotational axis X. Insignia portion 6A is formed by a plurality of characters arranged along the tire's circumference. These characters may display at least one of the following: the manufacturer's name, product name, brand, etc. Each character may be formed by a concave or convex line border, or the entire character may be concave or convex. For example, the characters of insignia portion 6A are provided as pattern region 7 in this embodiment.

[0054] like Figure 1As shown, patterned portions 6B are provided at two locations in the annular decorative region 5, sandwiched between two emblem portions 6A in the circumferential direction. Patterned portions 6B are provided with a pattern in which a parallelogram is curved to mimic the annular decorative region 5. For example, each pattern of patterned portion 6B is also provided as patterned region 7 of the embodiment.

[0055] Note that the shape of the pattern area 7 is not limited thereto, and various shapes may be used, including any shape, a shape depicting the manufacturer's name, product name, brand logo, or other symbols, or a shape depicting other numbers or characters.

[0056] Each of the patterned areas 7 in the embodiment has a reference surface 7a that follows the contour of the sidewall 3. Multiple protrusions 110, described below, are formed on this reference surface 7a. The formation of these multiple protrusions 110 allows the patterned area 7 to be visually distinguished from the surrounding area of ​​the patterned area 7. It should be noted that the reference surface 7a may extend axially outward from the contour of the sidewall 3, may be recessed axially inward from the contour of the sidewall 3, or may be located axially co-located with the contour of the sidewall 3.

[0057] Figure 2 An example of a tire forming mold for vulcanization-molding the tire 1 according to the embodiment is shown. Figure 2 1 is a meridian cross-sectional view of such a tire forming mold 10 along the axial direction of the tire 1 to be formed.

[0058] Figure 2 The tire forming mold 10 shown comprises a plurality of sector molds 11 arranged circumferentially along the outer circumference 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 sector molds 11, and a pair of bead rings (not shown). Figure 2 As shown by the dashed line, an unvulcanized tire 1a, which will become the tire 1, is positioned inside a tire forming mold 10. The assembly of the sector mold 11, side plates 12, and bead rings forms the forming mold for forming the tire 1. The outer surface of the tire 1 as a whole is formed by the inner surfaces of this forming mold—that is, the inner surfaces 11a of the sector mold 11, the inner surfaces 12a of the side plates 12, and the inner surfaces of the bead rings. Furthermore, an air bladder (not shown) is positioned inside the unvulcanized tire 1a to press the unvulcanized tire 1a against the inner surface of the tire forming mold 10 during vulcanization. The plurality of sector molds 11 primarily form the tread 4, while the pair of side plates 12 primarily form the sidewall 3. The pair of bead rings form the bead 2, and the air bladder forms the entire inner surface of the tire 1.

[0059] The unvulcanized tire 1 a is vulcanized in the tire forming mold 10 to form the rubber shape of the entire tire 1 , and a plurality of protrusions 110 described below are formed in the pattern region 7 .

[0060] Figure 3 It is a perspective view showing a plurality of protrusions 110 arranged in the pattern region 7 . Figure 4 is a top view showing a plurality of protrusions 110 arranged in the pattern area 7. Figure 3 T-direction view. Figure 5 is Figure 4 The sectional view is obtained by cutting the plurality of protrusions 110 arranged in the pattern area 7 at the position of the arrow AA in FIG. The plurality of protrusions 110 are provided so as to protrude from the reference surface 7a of the pattern area 7, but Figures 3 to 5 The figure shows a state where a plurality of protrusions 110 are provided protrudingly from the UV development reference surface 7b when the reference surface 7a of the pattern area 7 is UV developed. Figure 5 , only one protrusion 110 is shown as a cross section. The UV development reference plane 7b is a plane obtained by two-dimensionally developing the outer surface 3a of the three-dimensional sidewall 3.

[0061] A plurality of protrusions 110 are arranged so as to protrude substantially axially outward from the reference surface 7a. Figure 4 As shown, the protrusions 110 of this embodiment are regularly arranged in multiple rows. Specifically, within a row, the protrusions 110 are closely contacted and arranged at equal intervals (equal pitch), with adjacent rows offset by half a pitch relative to each other. It should be noted that the arrangement of protrusions 110 is not limited to a closely contacted arrangement. For example, the protrusions 110 can be arranged at predetermined intervals without being in close contact, or they can be randomly arranged within a range that maintains a predetermined arrangement density. The protrusions 110 include a recessed portion 111, a tapered main portion 112, and an outer edge portion 113.

[0062] The recess 111 is viewed from above ( Figure 3 When viewed from the direction of arrow T in FIG. 1 , the recess 111 is located at the center of the protrusion 110 and has a mortar-shaped (inverted conical or inverted pyramidal) inner surface. It should be noted that in this specification, the term "mortar-shaped" encompasses not only conical shapes but also pyramidal shapes such as triangular and quadrangular pyramids. The bottom of the recess 111 is formed into a slightly curved surface, which forms a roughly hemispherical inner surface.

[0063] The conical main body 112 forms the outer periphery of the protrusion 110. The conical main body 112 extends in a conical shape in the direction in which the protrusion 110 protrudes from the reference plane 7a. Here, "conical" means a shape that gradually widens, such as a conical surface. In addition, at a direction perpendicular to the reference plane 7a, Figure 5In the cross-sectional shape shown, it is preferred that the inclined surface of the conical main body 112 is symmetrical with the inclined surface of the concave portion 111, and the protrusion 110 of this embodiment is also symmetrical. Here, the inclined surface of the conical main body 112 is symmetrical with the inclined surface of the concave portion 111. Figure 5 The cross-sectional shape shown is linearly symmetrical. Therefore, if the angle formed between the inclined surface of the tapered main body 112 and the reference plane 7a is θ, and the angle formed between the inclined surface of the recess 111 and the reference plane 7a is α, the relationship θ = α is satisfied. This relationship makes the angle of light reflection in the tapered main body 112 and the angle of light reflection in the recess 111 substantially the same, facilitating optical design that includes light absorption and achieving uniform light absorption.

[0064] The outer edge portion 113 surrounds the concave portion 111 and forms the front end portion of the protrusion 110. Figure 5 In the example shown, the outer edge portion 113 is formed by a curved surface shape that smoothly connects the recessed portion 111 and the tapered main body portion 112. Figure 5 In the cross section shown, the outer edge portion 113 can be configured to smoothly connect the recessed portion 111 and the tapered main body portion 112 with a curvature radius R≈0.01 mm.

[0065] In addition, the outer edge portion 113 is not limited to a curved surface shape, and may be configured as a flat surface. Figure 6 1 is a cross-sectional view showing an example in which the outer edge portion 113 is configured as a flat surface. Figure 6 As shown, it is set as a flat surface parallel to the reference surface 7a.

[0066] A portion of the light reaching the recessed portion 111 of the protrusion 110 is reflected by the inclined surface of the recessed portion 111. This reflected light is then repeatedly reflected within the recessed portion 111. This repeated reflection of light within the recessed portion 111 gradually attenuates the light reaching the recessed portion 111 and is absorbed. Furthermore, a portion of the light reaching the tapered body portion 112 of the protrusion 110 is repeatedly reflected by the inclined surface of the tapered body portion 112. Part of this reflected light then reaches and is reflected by the tapered body portions 112 of other protrusions 110 located nearby. This repeated reflection of light within the tapered bodies 112 of multiple protrusions 110 gradually attenuates the light reaching the tapered body portions 112 and is absorbed. Consequently, a portion of the light entering the patterned area 7 provided with the multiple protrusions 110 is absorbed and does not escape. Consequently, when the patterned area 7 provided with the multiple protrusions 110 is visually recognized, the patterned area 7 appears darker than the outer surface 3a of the sidewall 3, which reflects the surrounding light.

[0067] The light absorption effect described above varies depending on the dimensions of each portion of protrusion 110. Furthermore, not only is effective light absorption required, but also stable manufacturing is required during the manufacturing process. Because the shape of protrusion 110 is a repetition of minute shapes, it may not be possible to stably form it into the desired shape. Therefore, experiments were conducted to produce multiple test pieces with varying shapes and dimensions of each portion of protrusion 110 and verify light absorption and forming accuracy.

[0068] Figure 7 is a table summarizing the experimental results. Figures 5 to 7 As shown, the maximum outer diameter of the protrusion 110 is set to D1, the maximum inner diameter of the recess 111 is set to D2, the height of the protrusion 110 from the reference surface 7a is set to H1, and the depth of the recess 111 is set to H2. Figure 5 、 6 In the cross section shown, the angle formed by the inclined surface of the tapered main body 112 and the reference plane 7a is θ. In the experiment, Examples 1 to 3 and Comparative Examples were prepared, and test pieces were actually made and compared. The design values ​​and measured values ​​of each test piece are shown in FIG. Figure 7 In addition, Figure 7 In FIG. 1 , the ratio of the depth H2 of the recess 111 to the height H1 of the protrusion 110 ( H2 / H1 ) is expressed as a depth ratio.

[0069] and then, Figure 7 The measured values ​​and brightness index of D2 and H1 are shown in the figure. The brightness index was measured using a colorimeter CR-20 manufactured by Konica Minolta Japan Co., Ltd. The sample was sized to cover the measurement port (φ8 mm). The observation light source was D65, and the L component value of the L*a*b* display system (color space) was used as the brightness index. The smaller the brightness index, the more visually recognizable as black (higher black density and higher contrast). Therefore, for the purpose of achieving a darker appearance in this embodiment, a smaller brightness index is preferred. Specifically, to achieve a darker appearance, a brightness index of 15 or less is preferred, and 10 or less is more preferred.

[0070] and then, Figure 7 The forming accuracy evaluation value is shown in . This forming accuracy evaluation value is the value obtained by dividing the measured value of H1 by the design value of H1. The closer this forming accuracy evaluation value is to 1.00, the higher the forming accuracy is. It is preferably 0.85 or more and 1.15 or less.

[0071] like Figure 7As shown, in Examples 1 to 3 and the comparative example, the forming accuracy evaluation values ​​are all within the range of 0.85 or more and 1.15 or less, and the formability is good. On the other hand, in the comparative example, the brightness index is 17.6, and the effect of looking darker is insufficient. In addition, in Examples 1 and 2, the brightness index is less than 9.0, and the effect of looking darker is very high. Based on these results, it can be said that the protrusion height H1 of the protrusion 110 is preferably 0.6 mm or more and 1.4 mm or less, and more preferably 1.0 mm or more and 1.3 mm or less. In addition, it can be said that the depth of the recess 111 is preferably 30% or more and 70% or less of the protrusion height H1 of the protrusion 110 (the depth ratio is 0.3 or more and 0.7 or less).

[0072] Furthermore, it can be said that the shape of outer edge portion 113 is more preferably a curved surface than a flat surface. This is because if outer edge portion 113 is a flat surface, more light will be reflected in the same direction at outer edge portion 113, reducing the darker appearance effect. Furthermore, if the radius of curvature of the curved surface of outer edge portion 113 is large, it is likely to cause the same adverse effect of reduced darker appearance caused by reflected light as in the case of a flat surface. Therefore, the radius of curvature of the curved surface of outer edge portion 113 is preferably small, with the curvature radius R preferably being 0.02 mm or less, and more preferably 0.01 mm or less.

[0073] Furthermore, the angle θ formed between the inclined surface of the tapered main body portion 112 and the reference surface 7 a is preferably not less than 60° and not more than 80°, and more preferably not less than 65° and not more than 75°.

[0074] According to the tire 1 of the present embodiment described above, the following effects are achieved.

[0075] (1) The tire 1 of this embodiment has a pattern area 7 on at least a portion of the outer surface of the sidewall 3, and the pattern area 7 is arranged to be visually recognizable as a portion different from the surrounding area of ​​the portion, wherein a plurality of protrusions 110 protruding from a reference plane 7a are provided in the pattern area 7, and the protrusions 110 have: a recess 111 having an inner surface in the shape of an inverted cone or an inverted pyramid; a tapered main body 112 forming the outer periphery of the protrusion 110 and extending in a tapered shape from the reference plane 7a in a direction in which the protrusion 110 protrudes; and an outer edge 113 surrounding the recess 111, wherein the protrusion 110 has a protruding height of not less than 0.6 mm and not more than 1.4 mm, and a depth of the recess 111 is not less than 30% and not more than 70% of the protruding height of the protrusion 110.

[0076] As a result, it is possible to provide a tire that has a higher black density than before, can achieve higher contrast, and has excellent formability.

[0077] (2) In the tire 1 described in (1), the outer edge portion 113 is formed by a curved surface shape that smoothly connects the recessed portion 111 and the tapered main body portion 112 .

[0078] This improves the black density and further enhances the contrast. In addition, since the degree of light reflection varies less depending on the viewing angle, the variation in black density (brightness) can be reduced.

[0079] (3) In the tire 1 described in (2), the radius of curvature of the outer edge portion 113 is 0.02 mm or less.

[0080] This improves the black density and can further enhance the effect of increasing the contrast.

[0081] (4) In the tire 1 described in (1) or (2), an inclination angle of the tapered main body portion 112 relative to the reference plane 7 a is not less than 60° and not more than 80°.

[0082] This improves the black density and can further enhance the effect of increasing the contrast.

[0083] (5) In the tire 1 described in (1) or (2), in the cross-sectional shape of the protrusion 110 perpendicular to the reference plane 7 a , the inclined surface of the tapered main body portion 112 is symmetrical to the inclined surface of the recess 111 .

[0084] This makes it possible to easily perform optical design including light absorption, and also make the light absorption effect uniform.

[0085] (Deformation method)

[0086] The present invention is not limited to the above-described embodiment, and various modifications and changes are possible, and these are also within the scope of the present disclosure.

[0087] (Variation 1) In the embodiment, the inclined surface of the tapered main body 112 and the inclined surface of the recess 111 are both conical surfaces. This is not limiting. For example, at least one of the inclined surface of the tapered main body 112 and the inclined surface of the recess 111 may be formed by a pyramidal surface such as a quadrangular pyramid or a triangular pyramid.

[0088] (Variation 2) In the embodiment, the outer edge portion 113 is a curved surface, and the curvature radius in the cross section is constant. However, this is not limiting. For example, the outer edge portion 113 may be a shape formed by combining multiple different curved surfaces.

[0089] It should be noted that the embodiments and modifications can be used in combination as appropriate, but detailed descriptions are omitted. In addition, the present disclosure is not limited to the embodiments described above.

Claims

1. A tire comprising a patterned area on at least a portion of an outer surface of a sidewall, wherein the patterned area is provided so as to be visually recognizable as a portion different from the surrounding area of ​​the portion, wherein: A plurality of protrusions protruding from the reference surface are provided in the pattern area. The protrusion has: a recess having an inner surface in the shape of an inverted cone or an inverted pyramid; a tapered main body portion forming an outer periphery of the protrusion and extending in a tapered shape from a reference plane toward a direction in which the protrusion protrudes; and an outer edge portion surrounding the concave portion, The protrusion height is not less than 0.6 mm and not more than 1.4 mm. The depth of the recess is not less than 30% and not more than 70% of the protrusion height of the protrusion.

2. The tire according to claim 1, wherein The outer edge portion is formed by a curved surface shape that smoothly connects the recessed portion and the tapered main body portion.

3. The tire according to claim 2, wherein: The curvature radius of the outer edge portion is 0.02 mm or less.

4. The tire according to claim 1 or 2, wherein: The inclination angle of the tapered main body portion relative to the reference plane is greater than or equal to 60° and less than or equal to 80°.

5. The tire according to claim 1 or 2, wherein: In the cross-sectional shape of the protrusion perpendicular to the reference plane, the inclined surface of the tapered main body portion and the inclined surface of the recessed portion are symmetrical.

Images