Tire

Abstract

The present invention provides a tire which has a higher black density than conventional tires and which can achieve a higher contrast ratio. 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 (7) being provided so as to be visible as a different portion 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) comprising: a recess (111) having an inverted conical or inverted pyramidal inner surface; an outer edge section (113) that surrounds the periphery of the recessed section (111); and a tapered main body section (112) connected to the reference surface (7a) from the outer edge section (113), the depth of the recessed section (111) being greater than the protruding 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, the tire disclosed in Patent Document 1 may not absorb enough light, and a tire with a higher light absorption effect is desired.

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

[0009] Means for solving problems

[0010] The 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 include: a recess having an inner surface in the shape of an inverted cone or an inverted pyramid; an outer edge portion surrounding the recess; and a conical main body portion connected to the reference plane from the outer edge portion, and the depth of the recess is greater than the protruding height of the protrusion.

[0011] Effects of the Invention

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

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

[0014] Figure 2An 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 1 The 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 1 As 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 pattern 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 the reference surface 7a. The pattern area 7 is visually distinguishable from the surrounding area of ​​the pattern area 7 by forming the multiple protrusions 110. 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 a surface located axially at the same position as the contour of the sidewall 3. However, in the protrusions 110 of this embodiment, as described below, the recesses 111 are formed to a position deeper than the reference surface 7a. Therefore, it is preferred that the reference surface 7a extend axially outward from the contour of the sidewall 3. This is because there is no concern that the recesses 111 will cause the sidewall 3 to become thinner.

[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 the protrusion 110 is observed from the direction of the arrow T in the figure, it is located at the center of the protrusion 110 and has a mortar-shaped (inverted cone-shaped or inverted pyramid-shaped) inner surface. It should be noted that in this specification, the mortar-shaped shape includes not only the conical shape but also the pyramid-shaped shapes such as triangular pyramid and quadrangular pyramid for explanation. The bottom of the recess 111 is formed into a small curved surface, and the small curved surface is formed into an inner surface shape of a roughly hemispherical shape. It should be noted that the depth H2 of the recess 111 (refer to Figure 5 ) is greater than the protrusion height H1 of the protrusion 110 (refer to Figure 5 ) is large, thereby improving the light absorption effect described later, and the details are as follows.

[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] Here, the light absorption effect varies depending on the size of each portion of the protrusion 110. Therefore, a plurality of test pieces having different shapes and sizes of each portion of the protrusion 110 were prepared, and an experiment to verify the light absorption property was conducted.

[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 4 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. This 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 17 or less is preferred, and 10 or less is more preferred.

[0070] like Figure 7 As shown, in Examples 1 to 4, the brightness index is 17 or less, which is significantly lower than the brightness index of 17.6 in the comparative example. Therefore, it can be confirmed that the protrusions 110 in Examples 1 to 4 are highly effective in absorbing light. This is due to the depth ratio being 1.0 or greater, that is, the depth H2 of the recess 111 being greater than the protrusion height H1 of the protrusion 110. More specifically, when comparing Example 1 and the comparative example, the protrusion height H1 of the protrusion 110 is the same, but the depth H2 of Example 1 is more than twice that of the comparative example 1. Consequently, Example 1 also achieves a better brightness index than the comparative example (appearing darker). Thus, by making the depth H2 of the recess 111 greater than the protrusion height H1 of the protrusion 110, the light absorption effect can be dramatically improved.

[0071] When recesses are provided, as in the structure disclosed in Patent Document 1 (Japanese Patent Application Laid-Open No. 2020-131904), it is generally not considered a configuration where the depth of the recess is deeper than the reference surface. This is because if the recess is deeper than the reference surface, the thickness of the tire sidewall is locally reduced. However, in the tire 1 of this embodiment, the depth H2 of the recess 111 is greater than the protrusion height H1 of the protrusion 110, thereby significantly improving the light absorption effect. Furthermore, as previously explained, by configuring the reference surface 7a to extend axially outward from the contour of the sidewall 3, the thickness of the sidewall 3 can also be appropriately ensured.

[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 70° and not more than 80°.

[0074] Furthermore, based on the actual measurement results of the brightness index, it can be said that the protrusion height H1 of the protrusion 110 is preferably not less than 0.5 mm and not more than 1.4 mm, and more preferably not less than 1.0 mm and not more than 1.3 mm.

[0075] According to the tire 1 of the present embodiment described above, the following effects are achieved.

[0076] (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 in a state that can be visually identified as a portion different from the surrounding area of ​​the portion, wherein a plurality of protrusions 110 protruding from a reference surface 7a are provided in the pattern area 7, wherein the protrusions 110 include a recessed portion 111 having an inner surface with an inverted cone or an inverted pyramid shape, an outer edge portion 113 surrounding the recessed portion 111, and a tapered main body portion 112 connected to the reference surface 7a from the outer edge portion 113, and the depth of the recessed portion 111 is greater than the protruding height of the protrusion 110.

[0077] This makes it possible to provide a tire that has a higher black density and can achieve higher contrast than conventional tires.

[0078] (2) In the tire 1 described in (1), the outer edge portion 113 is formed into a curved shape.

[0079] This improves the black density and can further enhance the effect of increasing the contrast.

[0080] (3) In the tire 1 described in (2), the radius of curvature of the outer edge portion 113 is 0.02 mm or less.

[0081] This improves the black density and can further enhance the effect of increasing the contrast.

[0082] (4) In the tire 1 described in (1) or (2), the tapered main body portion 112 has an inclination angle relative to the reference plane 7 a of not less than 60° and not more than 80°.

[0083] This improves the black density and can further enhance the effect of increasing the contrast.

[0084] (5) In the tire 1 according to (1) or (2), a protrusion height of the protrusion is 0.5 mm or more and 1.4 mm or less.

[0085] This improves the black density and further enhances the contrast. In addition, the height of the protrusion 110 does not become too high, and the moldability can be improved.

[0086] (6) 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 .

[0087] This makes it possible to easily perform optical design including light absorption, and also make the light absorption effect uniform.

[0088] (Deformation method)

[0089] 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.

[0090] (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.

[0091] (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.

[0092] It should be noted that the embodiments and modifications may be used in combination as appropriate, but detailed descriptions thereof will be omitted.

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 comprises: a concave portion having an inner surface in the shape of an inverted cone or an inverted pyramid; an outer edge portion surrounding the concave portion; and a tapered main body portion connected to the reference surface from the outer edge portion, The depth of the recess is greater than the protruding height of the protrusion.

2. The tire according to claim 1, wherein The outer edge portion is formed in a curved shape.

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: The protrusion has a protrusion height of 0.5 mm or more and 1.4 mm or less.

6. 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.

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