DECORATIVE BODY

TECHNICAL FIELD

The present disclosure relates to a decorative body formed on a tire side portion.

BACKGROUND ART

Japanese Patent Application Laid-Open (JP-A) Nos. 2013-71572, 2008-273505, 2008-189165, 2012-101754, and Japanese National-Phase Publication No. 2002-52294 disclose tires in which a tire side portion is contoured in order to improve the visual impact of the tire.

SUMMARY OF INVENTION
Technical Problem

In the tire disclosed in JP-A No. 2013-71572, plural pattern elements having the same outline shape and having directionality so as to cause light reflection characteristics to change continuously or in stages along one direction are disposed continuously to each other in a tire circumferential direction and a tire radial direction. The placement direction is changed periodically around the tire circumferential direction, and pattern elements adjacent to each other in the tire radial direction have different placement directions to each other. This placement of pattern elements causes the location where the pattern elements are disposed to appear to have solid contours to a person observing. However, although any unevenness present at an outer surface of a sidewall portion is rendered less obvious, the intention is not to improve the visual impact of the tire itself.

In the tire disclosed in JP-A No. 2008-273505, an outer surface of a sidewall portion is formed with concave and convex portions. Reflective faces are provided to the surfaces of at least some of the concave portions, and roughened faces are provided around the reflective faces so as to achieve changing light reflecting properties. Although the external appearance of the tire is improved, the intention is not to improve the visual impact of the tire itself. Moreover, if dirt enters the concave portions of the roughened faces, such dirt is difficult to remove.

In the tire disclosed in JP-A No. 2008-189165, a ring shaped decorative body configured by a collection of numerous polygonal pyramids is provided to a sidewall portion. Although this makes unevenness caused by a spliced edge or a folded-back edge of a carcass layer that appears at the surface of the sidewall portion less obvious, the intention is not to improve the visual impact of the tire itself.

In the tire disclosed in Japanese National-Phase Publication No. 2002-522294, light reflection is varied between a text portion and a background portion. Although this creates contrast between the text portion and the background portion, enabling the text to be distinguished clearly, the intention is not to improve the visual impact of the tire itself.

The tire disclosed in JP-A No. 2012-101754 generates a visual effect in which a second decorative body provided within a first decorative body appears to be emphasized, thereby enabling unevenness arising in an outer surface of a sidewall to be less obvious and enabling decorative qualities to be improved. However, the intention is not to improve the visual impact of the tire itself.

The decoration and the like applied to these tire side portions stands out when the tire is observed closely, and the respective technologies described above are employed to make unevenness of the tire side portion appear less obvious, to improve the visual impact of text or the like, and so on. The intention is not to improve the visual impact of the tire.

In consideration of the above circumstances, an object of the present disclosure is to provide a decorative body capable of improving the visual impact of a tire.

Solution to Problem

A decorative body according to a first aspect includes plural solid shapes including a bottom face configured at a surface of a tire side portion and plural inclined faces each inclined in a direction that is not a direction of the bottom face or a direction of a plane perpendicular to the bottom face. At least three types of the solid shapes have different vector orientations from each other when the tire side portion is viewed in plan view and when a vector is defined as an inclined face vector running in a direction from a highest location side toward a lowest location side of a inclined face having a smallest incline angle with respect to the tire side portion for a corresponding solid shape, with the highest location side of the vector defined as a start point of the vector and the lowest location side of the vector defined as an end point of the vector. A region is included in which the solid shapes having different vector orientations from each other are disposed adjacently to each other when the tire side portion is viewed in plan view, from 3 to 200 of the solid shapes are provided per 1 cm², and a surface area taken up by the inclined faces having the smallest incline angle occupies a range of from 70% to 100% per unit surface area in plan view.

In a decorative body that satisfies all these conditions, for example, light shone onto a tire can be reflected in the direction of an observer to the side of the tire using a number of discrete inclined faces from out of the plural inclined faces. Thus, when at least one out of the tire or the observer moves such that the tire and the observer move relative to each other, the inclined faces reflecting the light toward the observer change in a random fashion. Thus, the light appears to twinkle at plural different positions of the decorative body. In other words, the decorative body has an external appearance that appears to sparkle.

“Sparkling” is defined as follows.

A twinkling effect in which highlight points (points that appear brightest when viewed from a given range) on a target appear to change accompanying a change in viewpoint. Also, a twinkling effect in which highlight points change accompanying a change in an illuminating light source when viewed in a static state.

In the decorative body, when the number of solid shapes per unit surface area is small, the number of locations that appear to light up is too small, making a sparkling impression difficult to achieve. When the number of solid shapes per unit surface area is too large, the surface area of locations that appear to light up is too small, making it difficult to make the locations that appear to light up appear bright, and difficult to achieve a sparkling impression. Thus, from 3 to 200 of the solid shapes are disposed per 1 cm²in order that the decorative body achieves an external appearance that appears to sparkle.

Moreover, setting the surface area taken up by the inclined faces having the smallest incline angle to a range of from 70% to 100% per unit surface area of the decorative body when the decorative body is viewed in plan view enables the surface area of locations that reflect light toward an observer positioned directly in front of the tire to be secured, such that the locations that reflect light so as to appear to light up appear bright to the observer.

A second aspect is the decorative body according to the first aspect, wherein in cases in which the bottom face is a polygonal shape with four or more sides, a number of faces perpendicular to the bottom face is smaller than the number of sides of the bottom face for some of the plural solid shapes.

In this decorative body, in solid shapes in which the bottom face is a polygonal shape with four or more sides, when the number of faces perpendicular to the bottom face is smaller than the number of sides of the bottom face, at least one inclined face inclined with respect to the bottom face is formed.

When light such as sunlight is shone obliquely downward from above toward a face perpendicular to the bottom face of the solid shape (so as to run parallel to a tire side portion perpendicular to a road surface in a state in which a tire is fitted to a vehicle), and toward a face that is inclined with respect to the bottom face, the face that is inclined with respect to the bottom face is better able to reflect light toward an observer at the side of the tire (directly in front or at an oblique front side of the tire side portion) than the face that is perpendicular to the bottom face. Thus, the decorative body of the eighth aspect, in which the number of inclined faces that can be formed inclined with respect to the bottom face is at least one, enables the sparkling external appearance to be emphasized.

A third aspect is the decorative body according to the first aspect or the second aspect, wherein the bottom face of each of the solid shapes has a surface area of from 0.5 mm²to 50 mm².

When the number of solid shapes are too small, the locations that appear to light up are too small, making it difficult to make the locations that appear to light up appear bright, and making it difficult to achieve a sparkling impression. When the solid shapes are too large, the surface area of locations that appear to light up is too large, such that the sparking locations are perceived as faces. In other words, it is perceivable that the faces are sparkling, and it becomes difficult to achieve a sparkling impression. Thus, in order to emphasize the sparkling external appearance of the decorative body, the bottom face of each of the solid shapes is preferably formed with a surface area of from 0.5 mm²to 50 mm².

A fourth aspect is the decorative body according to anyone of the first aspect to the third aspect, wherein the decorative body has a surface area of at least 100 mm².

When the surface area of the decorative body is too small, the locations that appear to light up are too few, making it difficult to achieve a sparkling impression when the decorative body is viewed. Thus, the decorative body preferably has a surface area of at least 100 mm²in order to emphasize the sparkling impression when the decorative body is viewed.

A fifth aspect is the decorative body according to any one of the first aspect to the fourth aspect, wherein at least some of the plural solid shapes are solid shapes having different heights to each other.

In this decorative body, at least some of the plural solid shapes are solid shapes having different heights to each other, thereby enabling variation in the gradients of the inclined faces to be achieved. In other words, plural solid shapes with inclined faces with different gradients are included in the plural solid shapes, thereby enabling the sparkling external appearance to be emphasized compared to cases in which the inclined faces of the plural solid shapes all have the same gradient.

Advantageous Effect of Invention

The decorative body of the present disclosure enables the decorative body to be configured with an external appearance that appears to sparkle, and is thus capable of improving the visual impact of the tire.

BRIEF DESCRIPTION OF DRAWINGS

FIG. 1 is a plan view (face-on view of a tire) illustrating part of a tire side portion of a tire formed with a decorative body according to an exemplary embodiment in the present invention.

FIG. 2 is an enlarged plan view of a decorative portion illustrated in FIG. 1.

FIG. 3 is a plan view illustrating reflective cells.

FIG. 4 is a plan view illustrating reflective cells with heights of inclined faces of reflective pieces indicated by graded shading.

FIG. 5 is a plan view illustrating dimensions of a first set configured by a pair of reflective pieces.

FIG. 6 is an enlarged plan view illustrating a decorative portion with heights of inclined faces of reflective pieces indicated by graded shading.

FIG. 7(A) is a plan view illustrating a first set, FIG. 7(B) is a plan view illustrating the first set with heights of inclined faces of reflective pieces indicated by graded shading FIG. 7(C) is a vertical cross-section of the first set, and FIG. 7(D) is a diagram illustrating a relationship between shading density and height dimensions.

FIG. 8(A) is a plan view illustrating one reflective piece of a second set, FIG. 8(B) is a plan view illustrating the other reflective piece of the second set, FIG. 8(C) is a plan view illustrating the second set with heights of inclined faces of the reflective pieces indicated by graded shading. FIG. 8(D) is a cross-section illustrating the one reflective piece of the second set, and FIG. 8(E) is a cross-section illustrating the other reflective piece of the second set.

FIG. 9(A) is a plan view illustrating a third set, FIG. 9(B) is a plan view of the third set with heights of inclined faces of reflective pieces indicated by graded shading, and FIG. 9(C) is a vertical cross-section of the third set.

FIG. 10(A) is a plan view illustrating one reflective piece of a fourth set, FIG. 10(B) is a plan view illustrating the other reflective piece of the fourth set, FIG. 10(C) is a plan view illustrating the fourth set with heights of inclined faces of the reflective pieces indicated by graded shading. FIG. 10(D) is a cross-section illustrating the one reflective piece of the fourth set, and FIG. 10(E) is a cross-section illustrating the other reflective piece of the fourth set.

FIG. 11(A) to FIG. 1l(D) are a plan view and perspective views illustrating reflective cells configuring a decorative body according to another exemplary embodiment.

FIG. 12(A) to FIG. 12(D) are a plan view and perspective views illustrating reflective cells configuring a decorative body according to yet another exemplary embodiment.

FIG. 13(A) to FIG. 13(D) are a plan view and perspective views illustrating reflective cells configuring a decorative body according to yet another exemplary embodiment.

FIG. 14(A) to FIG. 14(D) are a plan view and perspective views illustrating reflective cells configuring a decorative body according to yet another exemplary embodiment.

FIG. 15(A) is a plan view illustrating a reflective cell set in which vector start points are adjacent to each other and vector orientations are in opposite directions to each other, FIG. 15(B) is a plan view illustrating a reflective cell set in which vector end points are adjacent to each other and vector orientations are in opposite directions to each other, FIG. 15(C) is a plan view illustrating three consecutive reflective cells (in a lateral direction) in which the vector orientations are in the same direction as each other, FIG. 15(D) is a plan view illustrating three consecutive reflective cells (in a longitudinal direction) in which the vector orientations are in the same direction as each other, FIG. 15(E) is a plan view illustrating a reflective cell set in which the vector orientations are different to each other, and FIG. 15(F) is a plan view illustrating a reflective cell set including a reflective cell with a vector and a reflective cell without a vector (with an apex face running parallel to a bottom face).

FIG. 16 is a plan view illustrating three consecutive reflective cells in a case in which a vector rotation direction changes by the same angle in the same rotation direction.

FIG. 17 is a perspective view to explain an apex face (inclined face) of a reflective cell.

FIG. 18 is a perspective view to explain an angle of an inclined face of a reflective cell.

FIG. 19 is a perspective view illustrating a vector of a triangular column shaped reflective cell.

FIG. 20 is a perspective view illustrating a vector of another triangular column shaped reflective cell.

FIG. 21 is a perspective view illustrating a vector of a square column shaped reflective cell.

FIG. 22 is a perspective view illustrating a vector of another square column shaped reflective cell.

FIG. 23(A) and FIG. 23(B) are a plan view and a side view illustrating three reflective cells having the same vector orientation as each other in plan view, and having inclined faces with the same incline angle as each other.

FIG. 24(A) and FIG. 24(B) are a plan view and a side view illustrating three reflective cells having the same vector orientation as each other in plan view, and having inclined faces with different incline angles to each other.

FIG. 25 is a table of test results.

DESCRIPTION OF EMBODIMENTS

Explanation follows regarding a tire 10 according to an exemplary embodiment in the present invention, with reference to FIG. 1 to FIG. 14.

As illustrated in FIG. 1, a tire side portion 12 of the tire 10 is provided with an annular decorative body 14. Note that as an example, the tire 10 of the present exemplary embodiment is a pneumatic tire for a passenger car.

As illustrated in FIG. 2 and FIG. 3, the decorative body 14 is configured by eight types of reflective pieces 16, as an example of solid shapes that appear substantially triangular when the tire side portion 12 is viewed in plan view. Specifically, the reflective pieces 16 are configured by reflective pieces 16A to 16H, the shapes of which will be described in detail later.

As illustrated in FIG. 3, in the present exemplary embodiment a first set 18A, a second set 18B, a third set 18C, and a fourth set 18D are configured as examples of third solid shape pairs having substantially rhomboidal external profiles configured by combining any two of the reflective pieces 16A to 160 so as to oppose each other along their longest sides. In a reflective cell 20 of the present exemplary embodiment, the first set 18A is configured by combining the reflective piece 16A and the reflective piece 16B in a substantially rhombus shape, the second set 18B is configured by combining the reflective piece 16C and the reflective piece 16D in a substantially rhombus shape, the third set 18C is configured by combining the reflective piece 16E and the reflective piece 16F in a substantially rhombus shape, and the fourth set 18D is configured by combining the reflective piece 16G and the reflective piece 16H in a substantially rhombus shape. The first set 18A, the second set 18B, the third set 18C, and the fourth set 18D are arranged in this sequence along one direction (the left-right direction in the illustration of FIG. 3) so as to configure the reflective cell 20 with a narrow elongated substantially parallelogram shaped external profile.

The decorative body 14 of the present exemplary embodiment is configured by tessellating the reflective cells 20 configured as described above as illustrated in FIG. 2, along both the length direction and short direction (a direction orthogonal to the length direction) of the reflective cells 20. As illustrated in FIG. 3, one reflective cell 20 and another reflective cell 20 adjacent in the short direction are disposed slightly offset with respect to one another in the length direction of the reflective cells 20.

As illustrated in FIG. 2, when the tire side portion 12 is viewed in plan view, the reflective cells 20 are disposed such that a length direction D (direction indicated by arrows) of the reflective cells 20 is inclined by 65° (the angle θ in FIG. 2) with respect to a radial direction r (direction indicated by arrows) of the annular decorative body 14.

Reflective Piece 16A

As illustrated in plan view in FIG. 5, the reflective piece 16A includes a first side 16Aa running parallel to the length direction D of the reflective cell 20, a second side 16Ab inclined at a comparatively large angle with respect to the length direction D of the reflective cell 20, and a third side 16Ac, this being the longest side, inclined at a comparatively small angle with respect to the length direction D of the reflective cell 20. Note that the first side 16Aa and the second side 16Ab are straight lines in plan view, whereas the third side 16Ac is curved, for example with a radius of curvature R of 73.7 mm, so as to arch toward the inside of the triangular shape. In the present exemplary embodiment, an angle θ1 formed between the first side 16Aa and the second side 16Ab is 106.1° (deg) in plan view.

The first side 16Aa of the reflective piece 16A has a length L1 of 2.1 mm, and a dimension h in a direction orthogonal to the first side 16Aa is 2.325 mm.

As an example, a connection portion 16As1 between the first side 16Aa and the second side 16Ab is formed in a circular are shape with a radius of curvature R of 2.1 mm. Moreover, a connection portion 16As2 between the first side 16Aa and the third side 16Ac, and a connection portion 16As3 between the second side 16Aa and the third side 16Ac, are, for example, formed with circular arc shapes with a radius of curvature R of 0.1 mm in plan view.

As illustrated in FIG. 7, considered overall, the reflective piece 16A has a triangular column shape that projects out by a short height from a base portion of the tire side portion 12.

In the reflective piece 16A, the third side 16Ac has the greatest height, this being a uniform height of 0.4 mm across the entire third side 16Ac. The height of an apex face of the reflective piece 16A (also referred to hereafter as an inclined face 16At) gradually decreases at a uniform incline angle on progression from the third side 16Ac toward the connection portion 16As1 between the first side 16Aa and the second side 6Ab. Namely, the height of the inclined face 16At is lowest (for example a height of 0 mm) at the connection portion 16As1. Note that the inclined face 16At is a planar face.

In FIG. 7(B), an incline direction (downward sloping direction) of the inclined face 16At of the reflective piece 16A is indicated by an arrow. The darker shaded area is higher, while the lighter shaded area is lower (see FIG. 7(D)).

Reflective Piece 16B

As illustrated in FIG. 7, the reflective piece 16B includes a first side 16Ba running parallel to the length direction D of the reflective cell 20, a second side 16Bb inclined at a comparatively large angle with respect to the length direction D of the reflective cell 20, and a third side 16Bc, this being the longest side, inclined at a comparatively small angle with respect to the length direction D of the reflective cell 20. As illustrated in FIG. 5, the first side 16Ba and the second side 16Bb of the reflective piece 16B are straight lines in plan view, whereas the third side 16Bc is curved, for example with a radius of curvature R of 73.7 mm, so as to arch toward the inside of the triangular shape. In the present exemplary embodiment, an angle θ1 formed between the first side 16Ba and the second side 16Bb is 106.1° (deg) in plan view.

As an example, a connection portion 16Bs1 between the first side 16Ba and the second side 16Bb is formed in a circular arc shape with a radius of curvature R of 2.1 mm in plan view. Moreover, a connection portion 16Bs2 between the first side 16Ba and the third side 16Bc, and a connection portion 16Ba3 between the second side 16Bb and the third side 16Bc, are, for example, formed with circular arc shapes with a radius of curvature R of 0.1 mm in plan view. In this manner, the plan view profile of the reflective piece 16B has point symmetry to the reflective piece 16A, with the symmetry centered on a center point of the first set 18A that has a substantially rhombus shape in plan view.

As illustrated in FIG. 7, considered overall, the reflective piece 16B has a triangular column shape that projects out by a short height from the base portion of the tire side portion 12. The height of an apex face of the reflective piece 16B (also referred to hereafter as an inclined face 16Bt) is highest at the connection portion 16Bs1 between the first side 16Ba and the second side 16Bb (for example at a height of 0.4 mm), and inclines downward on progression from the connection portion 16Bs1 toward the third side 16Bc, such that the entire third side 16Bc has the lowest height of the reflective piece 16B (for example a uniform height of 0 mm). Note that the inclined face 16Bt is a planar face.

In FIG. 7(B), an incline direction (downward sloping direction) of the inclined face 16Bt of the reflective piece 168 is indicated by an arrow. The darker shaded area is higher, while the lighter shaded area is lower.

Reflective Piece 16C As illustrated in FIG. 8, the reflective piece 16C has the same plan view profile (a triangular shape) as the reflective piece 16A.

Considered overall, the reflective piece 16C has a triangular column shape that projects out by a short height from the base portion of the tire side portion 12. In the reflective piece 16C, a first side 16Ca has the greatest height (for example a height of 0.4 mm), and the reflective piece 16C is inclined downward on progression from the first side 16Ca toward a connection portion 16Cs3 between a second side 16Cb and a third side 16Cc. The connection portion 16Cs3 has the lowest height of the reflective piece 16C (for example a height of 0 mm). Namely, an inclined face 16Ct of the reflective piece 16C is inclined downward on progression from the first side 16Ca toward the connection portion 16Cs3 between the second side 16Cb and the third side 16Cc, and has its lowest height at the connection portion 16Cs3 (for example, a height of 0 mm). Note that the inclined face 16Ct is a planar face.

In FIG. 8(C), an incline direction (downward sloping direction) of the inclined face 16Ct of the reflective piece 16C is indicated by an arrow. The darker shaded area is higher, while the lighter shaded area is lower.

Reflective Piece 16D

As illustrated in FIG. 8, the reflective piece 16D has the same plan view profile (a triangular shape) as the reflective piece 16B.

Considered overall, the reflective piece 16D has a triangular column shape that projects out by a short, uniform height (for example 0.2 mm) from the base portion of the tire side portion 12. Note that an apex face 16Dt of the reflective piece 16D is a planar face running parallel to a bottom face 16b.

Reflective Piece 16E

As illustrated in FIG. 9, the reflective piece 16E has the same plan view profile (a triangular shape) as the reflective piece 16A.

Considered overall, the reflective piece 16E has a triangular column shape that projects out by a short height from the base portion of the tire side portion 12. In the reflective piece 16E, a connection portion 16Es1 between a first side 16Ea and a second side 16Eb has the greatest height (for example a height of 0.4 mm), and the reflective piece 16E is inclined downward on progression toward a third side 16Ec. The third side 16Ec has the lowest height of the reflective piece 16E (for example a uniform height of 0 mm). Namely, an inclined face 16Et of the reflective piece 16E is inclined downward on progression from the connection portion 16Es1 between the first side 16Ea and the second side 16Eb toward the third side 16Ec, and has its lowest height at the third side 16Ec. Note that the inclined face Et is a planar face.

In FIG. 9(B), an incline direction (downward sloping direction) of the inclined face 16Et of the reflective piece 16B is indicated by an arrow. The darker shaded area is higher, while the lighter shaded area is lower.

Reflective Piece 16F

As illustrated in FIG. 9, the reflective piece 16F has the same plan view profile (a triangular shape) as the reflective piece 16B.

As illustrated in FIG. 9, considered overall, the reflective piece 16F has a triangular column shape that projects out by a short height from the base portion of the tire side portion 12. In the reflective piece 16F, a third side 16Fc has the greatest height (for example a height of 0.4 mm), and the reflective piece 16F is inclined downward on progression toward a connection portion 16Fs1 between a first side 16Fa and a second side 16Fb, such that the connection portion 16Fs1 has the lowest height of the reflective piece 16F (for example a height of 0 mm). Namely, an inclined face 16Ft of the reflective piece 16F is inclined downward on progression from the third side 16Fc toward the connection portion 16Fs1 between the first side 16Fa and the second side 16Fb, and has its lowest height at the connection portion 16Fs1. Note that the inclined face 16Ft is a planar face.

In FIG. 9(B), an incline direction (downward sloping direction) of the inclined face 16Ft of the reflective piece 16F is indicated by an arrow. The darker shaded area is higher, while the lighter shaded area is lower.

Reflective Piece 160

As illustrated in FIG. 10, the reflective piece 16G has the same plan view profile (a triangular shape) as the reflective piece 16A.

Considered overall, the reflective piece 16G has a triangular column shape that projects out by a short, uniform height (for example 0.2 mm) from the base portion of the tire side portion 12. An apex face 16Gt of the reflective piece 16G is a planar face running parallel to a bottom face 16b.

Reflective Piece 16H

As illustrated in FIG. 10, the reflective piece 16H has the same plan view profile (a triangular shape) as the reflective piece 16B.

As illustrated in FIG. 10, considered overall, the reflective piece 16H has a triangular column shape that projects out by a short height from the base portion of the tire side portion 12.

In the reflective piece 16H, a connection portion 16Hs3 between a second side 16Hb and a third side 16Hc has the greatest height (for example a height of 0.4 mm), and the reflective piece 16H is inclined downward on progression toward a first side 16Ha, such that the first side 16Ha has the lowest height of the reflective piece 16B (for example a uniform height of 0 mm). Namely, an inclined face 16Ht of the reflective piece 16H is inclined downward on progression from the connection portion 16Hs3 between the second side 16Hb and the 16Hc toward the first side 16Ha, and has its lowest height at the first side 16Ha. Note that the inclined face 16Ht is a planar face.

In FIG. 10(C), an incline direction (downward sloping direction) of the inclined face 16Ht of the reflective piece 16H is indicated by an arrow. The darker shaded area is higher, while the lighter shaded area is lower

As illustrated in FIG. 3, narrow elongated rhombus shaped gaps S1 are formed extending in a diagonal direction between the reflective piece 16A and the reflective piece 168, between the reflective piece 168 and the reflective piece 16C, between the reflective piece 16E and the reflective piece 16F, and between the reflective piece 16G and the reflective piece 16H, and correspond to the base portion of the tire side portion 12.

Moreover, a gap S2 of uniform width (for example 0.1 mm) is provided between one reflective cell 20 and another reflective cell 20 arranged in the short direction of the reflective cells 20. Such gaps S2 also correspond to the base portion of the tire side portion 12.

As illustrated in FIG. 4, the configuration of the decorative body 14 of the present exemplary embodiment requires a minimum of three types of reflective pieces 16 with different vector orientations. As illustrated in FIG. 4, in the decorative body 14 of the present exemplary embodiment, the vector orientations of the reflective piece 16A, the reflective piece 16C, the reflective piece 16E, and the reflective piece 16H are different from each other as an example.

Furthermore, the decorative body 14 requires a region to be provided in which adjacent reflective pieces 16 are disposed so as to have different vector orientations from each other (the reflective piece 16D and the reflective piece 16G are exempt from this requirement as they do not include vectors). In the decorative body 14 of the present exemplary embodiment as illustrated in FIG. 4, as an example, the adjacent reflective piece 16B and reflective piece 16C have different vector orientations from each other.

Moreover, the decorative body 14 requires from 3 to 20 of the reflective pieces 16 to be provided per 1 cm. From 10 to 100 of the reflective pieces 16 are preferably provided per 1 cm². In the decorative body 14 of the present exemplary embodiment, approximately 18 of the reflective pieces 16 are provided per 1 cm².

There is a requirement for the proportion of the surface area taken up by the inclined faces having the smallest incline angle to occupy a range of from 70% to 100% of the decorative body 14 per unit surface area when the decorative body 14 is viewed in plan view.

In the present exemplary embodiment, the proportion of the surface area occupied by the inclined faces having the smallest incline angle (namely the inclined face 16At of the reflective piece 16A, the inclined face 16Bt of the reflective piece 16B, the inclined face 16Ct of the reflective piece 16C, the inclined face 16Et of the reflective piece 16E, and the inclined face 16Ft of the reflective piece 16F) is approximately 75% of the decorative body 14 per unit surface area.

The respective apex faces (inclined faces) of the reflective pieces 16 of the decorative body 14 are preferably smoother than the tire side portion 12 so as to reflect light more regularly, or in other words so as to scatter light less. The surface roughness thereof is preferably from 1 to 15 Rz (Rt) in ten-spot average roughness as defined in JIS B 0601.

The surface area of the decorative body 14 is preferably at least 100 mm².

The surface area of the bottom face 16b of each of the reflective pieces 16A to 16H is preferably within a range of from 0.5 mm²to 50 mm².

The incline angles (with respect to the bottom face 16b) of the inclined face 16At of the reflective piece 16A, the inclined face 16Bt of the reflective piece 16B, the inclined face 16Ct of the reflective piece 16C, the inclined face 16Et of the reflective piece 16E, the inclined face 16Ft of the reflective piece 16F, and the inclined face 6t of the reflective piece 16G are preferably within a range of from 5° to 60° are more preferably within a range of from 5° to 45°, and are even more preferably within a range of from 10° to 45°.

Operation and Advantageous Effects

When light (for example external light such as sunlight) is shone onto the decorative body 14, this light is reflected by the respective apex faces of the respective reflective pieces. The respective apex faces of the respective reflective pieces configuring the decorative body 14 face in various directions (see FIG. 6), and the tire side portion 12 on which the decorative body 14 is formed has a curved face. Accordingly, for example, when an observer standing directly in front or at an oblique front side of the tire 10 observes the tire 10, the apex faces reflecting the light toward the observer are distributed between various positions in the decorative body 14. When the tire 10 rotates, or when the observer moves while the tire 10 is stationary, such that the observer and the decorative body 14 of the tire 10 move relative to each other, the apex faces reflecting the light toward the observer change together with this relative movement, such that the positions of locations (namely the inclined faces and the apex faces) that appear to light up when the observer looks at the decorative body 14 change randomly to create a shifting impression, giving the decorative body 14 an external appearance that appears to sparkle.

In this manner, the decorative body 14 is capable of improving the visual impact of the tire 10 of the present exemplary embodiment, and capable of creating an impression of high quality stemming from a textured effect.

As illustrated in FIG. 4, the decorative body 14 of the present exemplary embodiment includes four types of the reflective pieces 16 having different vector orientations from each other when the tire side portion 12 is viewed in plan view (these can be broadly categorized as the reflective pieces 16A and 16B having upper left-oriented vectors (arrows), the reflective piece 16C having a lower left-oriented vector, the reflective piece 16H having a downward-oriented vector, and the reflective pieces 16E and 16F having lower right-oriented vectors). Accordingly, the sparkling appearance can be enhanced in comparison to cases in which only reflective pieces 16 with the same vector orientation as each other are provided, or cases in which only two types of reflective pieces 16 with different vector orientations from each other are provided.

The decorative body 14 of the present exemplary embodiment includes a region where reflective pieces 16 with different vector orientations from each other when the tire side portion 12 is viewed in plan view are disposed adjacently to each other (for example the region where the reflective piece 16B and the reflective piece 16C are disposed adjacently to each other, and a region where the reflective piece 16A and the reflective piece 16H are disposed adjacently to each other (see FIG. 6, not illustrated in FIG. 4)). This enables the sparkling impression to be enhanced in comparison to configurations not including such regions.

Note that in cases in which plural reflective pieces 16 having the same vector orientation as each other are provided adjacently to each other such that their highest sides link up in a straight line, the reflective pieces create a ridge-like appearance (similarly to the ridge of a mountain range), and light-reflecting locations line up, making a sparkling impression with points that appear to light up more difficult to achieve. Accordingly, adjacent reflective pieces 16 preferably have different vector orientations from each other.

The decorative body 14 of the present exemplary embodiment includes from 3 to 200 of the reflective pieces 16 per 1 cm². Accordingly, the sparkling impression can be emphasized in comparison to cases in which the number of reflective pieces 16 per 1 cm²is 2 or fewer, or cases in which the number of reflective pieces 16 per 1 cm²is greater than 200.

In the present exemplary embodiment, the proportion of the surface area taken up by the inclined faces having the smallest incline angle occupies a range of from 70% to 100% of the decorative body 14 per unit surface area when the decorative body 14 is viewed in plan view. This enables the sparkling impression to be emphasized in comparison to cases in which the proportion is set below 70%.

The decorative body 14 of the present exemplary embodiment is set with a surface area of at least 100 mm². This enables the sparkling impression to be emphasized in comparison to cases in which the surface area is less than 100 mm².

In the decorative body 14 of the present exemplary embodiment, the surface area of the bottom face 16b of each of the reflective pieces 16A to 16H is set within a range of from 0.5 mm²to 50 mm. This enables the sparkling impression to be emphasized in comparison to cases in which the surface area of the bottom face 16b is not within the range of from 0.5 mm²to 50 mm²

In the decorative body 14 of the present exemplary embodiment, the reflective cells 20 are each configured by the eight types of reflective pieces 16A to 16G The reflective cells 20 are tessellated along both the length direction and the short direction to configure the decorative body 14. This enables mold design and processing to form the tire 10 to be simplified in comparison to cases in which the inclined faces of all the reflective pieces configuring the decorative body 14 have different vectors to each other.

Other Exemplary Embodiments

Although explanation has been given regarding the tire 10 according to an exemplary embodiment in the present invention, the present invention is not limited to the above. Obviously, various modifications may be implemented within a range not departing from the spirit in the present invention.

In the exemplary embodiment described above, the greatest height of the reflective pieces 16A, 16B, 16C, 16E, 16F, and 16H is 0.4 mm. However, the greatest height is not limited to 0.4 mm. Moreover, although the heights of the reflective pieces 16D and 16G are 0.2 mm, the heights are not limited to 0.2 mm. Note that the reflective pieces 16A to 16H preferably project out from the base portion of the tire side portion 12 by 0.1 mm to 1.5 mm.

In the exemplary embodiment described above, each of the reflective pieces 16 configuring the decorative body 14 has a triangular column shape. However, the present invention is not limited thereto, and for example, the decorative body 14 may be configured by reflective pieces 22 with square column shapes having a square shape in plan view as illustrated in FIG. 11(A), with inclined faces 22t thereof having vectors running in different directions to each other as illustrated in FIG. 11(B) to FIG. 11(D). Alternatively, the decorative body 14 may be configured by reflective pieces 24 with circular column shapes having a circular shape in plan view as illustrated in FIG. 12, with inclined faces 24t thereof having vectors running in different directions to each other as illustrated in FIG. 12(B) to FIG. 12(D). Alternatively, the decorative body 14 may be configured by reflective pieces 26 with pentagonal column shapes having a pentagonal shape in plan view as illustrated in FIG. 13, with inclined faces 26t thereof having vectors running in different directions to each other as illustrated in FIG. 13(B) to FIG. 13(D). Alternatively, the decorative body 14 may be configured by reflective pieces 28 with hexagonal column shapes having a hexagonal shape in plan view as illustrated in FIG. 14, with inclined faces 28t thereof having vectors running in different directions to each other as illustrated in FIG. 14(B) to FIG. 14(D). In this manner, various other shapes may be adopted for the plan view profiles of the reflective pieces. Moreover, the decorative body 14 may be configured by a combination of reflective pieces having different shaped bottom faces,

Additional explanation follows regarding the decorative body 14.

As an example, a first solid shape pair 30 is defined as a pair of the reflective pieces 22 disposed adjacently to each other with a vector (arrow) start point of one of the reflective pieces 22 and the vector start point of the other of the reflective pieces 22 being adjacent to each other, and the vector of the one reflective piece 22 and the vector of the other reflective piece 22 being oriented in opposite directions to each other as illustrated in FIG. 15(A). A second solid shape pair 32 is defined as a pair of the reflective pieces 22 disposed adjacently to each other with a vector end point of one of the reflective pieces 16 and a vector end point of the other of the reflective pieces 22 being adjacent to each other, and the vector of the one reflective piece 22 and the vector of the other reflective piece 16 being oriented in opposite directions to each other as illustrated in FIG. 15(B). A solid shape group 34 is defined as a collection of three or more consecutive reflective pieces 22 having the same vector orientation as each other, as illustrated in FIG. 15(C) and FIG. 15(D). A third solid shape pair 36 is defined as a pair of two of the reflective pieces 22 not belonging to any out of the first solid shape pair 30, the second solid shape pair 32, or the solid shape group 34, as illustrated in FIG. 15(E) and FIG. 15(F). A first condition is satisfied when the combined surface area of the third solid shape pairs 36 is greater than the combined surface area of the first solid shape pairs 30 when the tire side portion 12 is viewed in plan view. A second condition is satisfied when the combined surface area of the third solid shape pairs 36 is greater than the combined surface area of the second solid shape pairs 32 when the tire side portion 12 is viewed in plan view. A third condition is satisfied when the combined surface area of the third solid shape pairs 36 is greater than the combined surface area of solid shape groups 34. The decorative body 14 should satisfy all of the first condition, the second condition, and the third condition. In other words, as long as the above conditions are satisfied, the first solid shape pair 30, the second solid shape pair 32, and the solid shape group 34 may be present to some extent in the decorative body 14. Note that in order to emphasize the sparkling impression, the decorative body 14 preferably satisfies a relationship in which the combined surface area of the third solid shape pairs 36 is greater than the combined surface area of the first solid shape pairs 30, plus the combined surface area of the second solid shape pairs 32, plus the combined surface area of the solid shape groups 34.

Note that the first solid shape pair 30, the second solid shape pair 32, and the first solid shape group 34 make the sparkling impression more difficult to obtain, and thus do not need to be present in the decorative body 14. In the decorative body 14 in the exemplary embodiment described above, the third solid shape pair 30 corresponds to the first set 18A, the second set 18B, the third set 18C, and the fourth set 18D. In the decorative body 14 in the exemplary embodiment described above, configurations corresponding to the first solid shape pair 30, the second solid shape pair 32, and the solid shape group 34 described above are not provided.

Moreover, in the decorative body 14 it is preferable to eliminate configurations in which, when as illustrated in FIG. 16 as an example, three of the reflective pieces 22 disposed consecutively from one side to another side are considered together in plan view of the tire side portion 12, a rotation direction orientation of the vectors changes by the same angle in the same rotation direction from the one side to the other side with reference to a normal line to the surface of the tire side portion 12 (for example 90° in FIG. 16). If three reflective pieces 22 in which the rotation direction orientation of the vectors changes by the same angle in the same rotation direction are consecutive to each other, this creates the impression of a regular arrangement of the inclined faces, with the result that the arrangement of the inclined faces that reflect light appears insufficiently random.

Additional explanation follows regarding the light reflecting apex faces of the reflective pieces.

In the present invention, within the reflective pieces serving as examples of solid shapes, the face that reflects light toward an observer in order to obtain a sparkling impression is the inclined face having the smallest incline angle with respect to the bottom face of the reflective piece. As illustrated in FIG. 17, when considering a reflective piece 22 with a square shaped bottom face, the highest location (apex) 22T of the reflective piece 22 is preferably positioned above and further toward a peripheral outside of the bottom face of the reflective piece 22 than the center of gravity G of the bottom face of the reflective piece 22 in plan view, in order to increase the surface area of the inclined face that reflects light. Note that although not illustrated in the drawings, in cases in which the highest location is a side, a length direction central portion of that side configures the apex 22T. In the reflective piece 22 illustrated in FIG. 17, the highest location 22T is positioned at a location close to a side 23a of the bottom face. This enables a face to be formed with the largest surface area (the inclined face having the smallest incline angle with respect to the bottom face) out of the plural faces other than the bottom face of the reflective piece 22.

As illustrated in FIG. 18, when considering a triangular shaped hypothetical plane 25 including a perpendicular line HL that passes through the highest location 22T of a reflective piece 22 and is perpendicular to the bottom face, and also includes a given point 23ap on the side 23a closest to the highest location 22T out of the sides of bottom face and a given point 23bp on a side 23b opposing the side 23a, if an angle formed between the bottom side of the hypothetical plane 25 and the sloping side on one side of the hypothetical plane 25 (the side linking the highest location 22T and the point 23ap together) is denoted θa, and an angle formed between the bottom side of the hypothetical plane 25 and the other sloping side of the hypothetical plane 25 (the side linking the highest location 22T and the given point 23bp) is denoted θb, then θb is preferably no less than 85° and no greater than 95°. This enables the surface area of the inclined face 22t set with the smallest incline angle with respect to the bottom face of the reflective piece 22 to be increased, thus enabling the sparkling impression to be emphasized.

Additional explanation follows regarding vectors of the light reflecting apex faces of the reflective pieces.

In the reflective pieces serving as examples of solid shapes, the vector of the inclined face is defined as the direction from the highest location side toward the lowest location side of the inclined face having the smallest incline angle with respect to the bottom face of the reflective piece. However, as illustrated in FIG. 19, for example, in the triangular column shaped reflective pieces 16, in cases in which an apex 16T of any of the triangular shapes is the highest location and a side 16c opposing the apex 16T is the lowest location, the direction from the apex 16T toward a center point 16cc of the side 16c corresponds to the vector (as indicated by the arrow).

As illustrated in FIG. 20, in the triangular column shaped reflective pieces 16, in cases in which the side 16c of any of the triangular shapes is the highest location (with a uniform height) and a triangular apex 16p opposing the side 16c is the lowest location, the direction from the center point of the side 16c toward the apex 16p corresponds to the vector (as indicated by the arrow).

As illustrated in FIG. 21, in the square column shaped reflective pieces 22, in cases in which a side 22a of any of the square shapes is the highest location (with a uniform height) and an opposing side 22b is the lowest location (with a uniform height), the direction from the center point of the side 22a toward the center point of the side 22b corresponds to the vector (as indicated by the arrow).

As illustrated in FIG. 22, in the square column shaped reflective pieces 22, in cases in which a corner 22p of any of the square shapes is the highest location, and an opposing corner 22d is the lowest location, the direction from the one corner 22p to the other corner 22d corresponds to the vector (as indicated by the arrow).

Regardless of the shape, if the inclined face having the smallest incline angle with respect to the bottom face of the reflective piece is highest at a side with a uniform height, and lowest at a side with a uniform height, the vector start point is at the center point of the highest side, and the vector end point is at the center point of the lowest side. Moreover, in cases in which the inclined face has a circular shape, an elliptical shape, or the like, the highest point of an outer peripheral portion of the inclined face is the vector start point, and the lowest point of the outer peripheral portion of the inclined face is the vector end point.

Note that if a case in which three reflective pieces 22 with inclined faces 22t having the same incline angle as each other are consecutive to each other as illustrated in FIG. 23 is compared to a case in which three reflective pieces 22 with inclined faces 22t having different incline angles and heights to each other are consecutive to each other as illustrated in FIG. 24, the latter is preferable in terms of obtaining a random appearance. Note that three or more of the reflective pieces 22 with inclined faces 22t having different incline angles and heights to each other may be provided consecutively to each other.

Test Examples

FIG. 25 illustrates evaluation (sensory evaluation) results ranked in five grades, namely A, B, C, D, or E, to represent the level of the sparkling impression of decorative bodies having different proportions taken up by the combined surface area of the inclined faces having the smallest incline angle per unit surface area of the decorative body when the decorative body is viewed in plan view, and different densities of the reflective pieces disposed in the decorative body 14.

The decorative bodies employed in the test are configured by reflective pieces having a triangular shape in plan view.

Sensory Evaluation Test Method

- In anticipation of being observed on a tire fitted to a vehicle, the decorative body is observed as a target in a state illuminated by light from above at an oblique angle of 45° from directly in front of the tire side surface applied with the target. The decorative body is observed from a position perpendicular to and directly in front of the tire side surface. The decorative body is observed while moving toward the left and right by no greater than 50 cm each side to evaluate the sparkling impression.
- If the observer is not moving, as above the decorative body is evaluated by being observed from a position perpendicular to and directly in front of the tire side surface while rotating the tire by 45° to both the left and right.

The sensory evaluation results signify the following: A=superb, B=very good, C=good, D=acceptable, E=unacceptable.

It can be seen from the test results in FIG. 25 that the sparkling impression differs depending on the combination of the proportion of the surface area taken up by the inclined faces of the reflective pieces (Configuration 1) and the density of the reflective pieces (Configuration 2).

Namely, it can be seen from the test results that when the decorative body 14 is viewed in plan view along the axial direction of the tire 10, securing a reflective surface area that is somewhat large (70% or greater) for the surface area taken up by the inclined faces of the reflective pieces is preferable.

Moreover, it can be seen from the test results that the density of the reflective pieces disposed in the decorative body 14 is preferably from 3 to 200 per 1 cm², and is more preferably from 10 to 100 per 1 cm².

The disclosure of Japanese Patent Application No. 2017-238079, filed on Dec. 12, 2017, is incorporated in its entirety by reference herein.

All cited documents, patent applications, and technical standards mentioned in the present specification are incorporated by reference in the present specification to the same extent as if each individual cited document, patent application, or technical standard was specifically and individually indicated to be incorporated by reference.

DECORATIVE BODY

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