tire

Abstract

This allows for richer expression in the pattern area on the outer surface of the tire. [Solution] The tire 10 has a pattern region 20 formed on its outer surface and having a base portion 22, a raised bottom portion 23 provided in the pattern region 20 and rising from the base portion 22, and minute protrusions 24 formed on the base portion 22 and the raised bottom portion 23, respectively, wherein the density of minute protrusions 24A on the base portion 22 is greater than the density of minute protrusions 24B on the raised bottom portion 23.

Description

Technical Field

[0006] , ,

[0001] The present invention relates to a tire having a pattern area formed on its outer surface.

Background Art

[0002] Conventionally, fine protrusions have been formed on the side portion of a tire to form a pattern having contrast. For example, Patent Document 1 discloses a configuration in which the first surface portion and the second surface portion of a decorative area (pattern area) are arranged stepwise via a first step. The protruding height h1 of the first minute protrusion of the first surface portion is made equal to the sum of the height H1 of the first step and the protruding height h2 of the second minute protrusion of the second surface portion. That is, the protruding height of the first minute protrusion from the outer surface of the tire is made equal to the protruding height of the second minute protrusion. And it is described that the blackness degree of the pattern area is increased by the minute protrusions.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] However, it is considered that there is still room for improvement in the expression of the pattern area.

[0005] An object of the present invention is to enable richer expression of the pattern area on the outer surface of a tire.

Means for Solving the Problems

[0006] A tire according to the first embodiment has a pattern region formed on the outer surface of the tire and having a base portion, a raised portion provided in the pattern region and rising from the base portion, and minute protrusions formed on the base portion and the raised portion, respectively, wherein the density of the minute protrusions on the base portion is greater than the density of the minute protrusions on the raised portion.

[0007] The outer surface of this tire has a pattern region having a base portion. Here, the outer surface of the tire refers to the surface visible from the outside, such as the tire side portion, tread portion, bottom of the tread grooves, and groove walls. Furthermore, the tire of the present invention includes both pneumatic and non-pneumatic tires.

[0008] In this tire, these micro-protrusions are formed on the base and raised sections, which suppresses the reflection of light incident on the pattern area compared to the area outside the pattern area, while creating a difference in how light is reflected between the base and raised sections within the pattern area. If the density of micro-protrusions on the raised section is greater than the density of micro-protrusions on the base section, it is possible to further suppress the reflection of light on the base section while allowing the reflection of light on the raised section, thereby creating an even greater difference in how light is reflected.

[0009] In the second embodiment of the tire, the heights of the minute protrusions relative to the base portion are equal to those of the tire in the first embodiment.

[0010] In this tire, the heights of the micro-protrusions relative to the base are equal, so the depth from the tip of a micro-protrusion to the base is greater than the depth from the tip of a micro-protrusion to the raised base. Therefore, light reflection on the base side of the pattern region can be suppressed more than on the raised base side.

[0011] The third embodiment is a tire according to the first or second embodiment, wherein the height of the minute protrusions with respect to the base portion is 0.1 mm or more and 1.0 mm or less, and the distance between adjacent minute protrusions is 0.1 mm or more and 1.0 mm or less.

[0012] With this tire, by appropriately setting the height and spacing of the micro-protrusions, it is possible to create contrast through differences in light reflection.

[0013] A fourth aspect is a tire according to the third aspect, wherein the micro-protrusions include extensions that extend in multiple directions from a base point in a plan view, and the extension of one micro-protrusion is connected to the extension of another adjacent micro-protrusion by a connecting portion.

[0014] In this tire, the protruding portions of the micro-protrusions are connected by connecting parts, so the micro-protrusions support each other through the connecting parts, suppressing the collapse of the micro-protrusions. This improves durability. [Effects of the Invention]

[0015] According to the present invention, it is possible to enable richer expression in the pattern area on the outer surface of the tire. [Brief explanation of the drawing]

[0016] [Figure 1] This is a front view showing a tire according to the first embodiment. [Figure 2] This is an enlarged cross-sectional view showing minute protrusions in the pattern region. [Figure 3] This is a further enlarged cross-sectional view of Figure 2. [Figure 4] This is a perspective view showing a modified example of a micro-projection. [Figure 5] This is a front view showing a tire according to the second embodiment. [Figure 6] This is an enlarged plan view showing the planar shape of the first pattern region. [Figure 7] (A) is an enlarged plan view showing a portion of the first pattern area, and (B) is an enlarged plan view showing a portion of the second pattern area. [Figure 8] This is a cross-sectional view showing the first asterisk projection. [Modes for carrying out the invention]

[0017] Hereinafter, embodiments for carrying out the present invention will be described based on the drawings. Components denoted by the same reference numerals in each drawing mean the same or similar components. In the embodiments described below, redundant explanations and reference numerals may be omitted. Further, the drawings used in the following description are all schematic, and the dimensional relationships of each element shown in the drawings, the ratios of each element, etc. are not necessarily the same as the actual ones. Also, the dimensional relationships of each element and the ratios of each element are not necessarily the same even among a plurality of drawings.

[0018] In the drawings, the direction of arrow C indicates the tire circumferential direction, and the direction of arrow R indicates the tire radial direction. The tire radial direction means a direction orthogonal to the tire rotation axis (not shown).

[0019] The outer surface of the tire 10 to be described later refers to a surface visible from the outside, such as the tire side portion 12, the tread portion, the groove bottom of the tread, the groove wall, etc. Further, the tire 10 according to the present embodiment includes both pneumatic tires and non-pneumatic tires.

[0020] [First Embodiment] In Figure 1, a decorative portion 14 is formed on the tire side portion 12 of the tire 10 according to this embodiment. The decorative portion 14 is in the shape of a strip-like arc and is formed at two symmetrical positions on either side of the tire central axis CE (see Figure 1). The decorative portion 14 has a pattern area 20 and a character area 16. The character area 16 displays characters such as "ABCDEFGH" on a smooth surface. In the decorative portion 14A on the upper side of Figure 1, the pattern area 20 is a kind of decorative band in the portion of the decorative portion 14A other than the character area 16, and is formed to surround the character area 16. On the other hand, in the decorative portion 14B on the lower side of Figure 1, the pattern area 20 is the same area as the character area 16 of the decorative portion 14B, and the portion of the decorative portion 14B other than the character area 16 is the same as the outer surface of the tire side portion 12 other than the decorative portion 14. In this embodiment, the decorative portion 14A will be described. The decorative portion 14, including the pattern area 20, can be formed by creating corresponding irregularities within the tire mold using laser processing. The pattern area 20 may also be positioned outside the tire radial radius R beyond the tire's maximum width (the maximum straight-line distance between the tire sidewalls).

[0021] In Figure 2, the tire 10 has a pattern area 20, a raised base portion 23, and minute protrusions 24 as unit patterns.

[0022] The pattern area 20 is formed on the outer surface of the tire 10 and has a base portion 22. The base portion 22 forms the bottom surface within the pattern area 20. The base portion 22 may be a recessed portion relative to the outer surface of the tire side portion 12.

[0023] The raised portion 23 is provided in the pattern area 20 and is a part that rises from the base portion 22. The height of the raised portion 23 relative to the base portion 22 may be constant or may vary depending on the location. The height may also vary within a single raised portion 23. In other words, the top surface of the raised portion 23 may be curved or inclined relative to the base portion 22. The proportion of the raised portion 23 in the pattern area 20 and the range of the raised portion 23 can be set arbitrarily.

[0024] The micro-protrusions 24 are formed on the base portion 22 and the raised portion 23, respectively. Here, the micro-protrusions on the base portion 22 are denoted as micro-protrusions 24A, and the micro-protrusions on the raised portion 23 are denoted as micro-protrusions 24B. The density of micro-protrusions 24A on the base portion 22 is greater than the density of micro-protrusions 24 on the raised portion 23. The ratio of the density of micro-protrusions 24A to the density of micro-protrusions 24 is between 1.1:1 and 20:1.

[0025] Furthermore, the width W1 of the tip of the micro-protrusion 24A of the base portion 22 may be less than or equal to the width W2 of the tip of the micro-protrusion 24B of the raised portion 23. In other words, the width W1 of the tip of the micro-protrusion 24A may be equal to the width W2 of the tip of the micro-protrusion 24B, and the width W2 of the tip of the micro-protrusion 24B may be greater than the width W1 of the tip of the micro-protrusion 24A. As shown in Figure 4, the micro-protrusion 24A may be cone-shaped and the micro-protrusion 24B may be frustoconical. Although not shown in the figure, if both micro-protrusions 24A and 24B are frustoconical, the area of ​​the top surface of the micro-protrusion 24B may be equal to the area of ​​the top surface of the micro-protrusion 24A, and the area of ​​the top surface of the micro-protrusion 24B may be greater than the area of ​​the top surface of the micro-protrusion 24A.

[0026] In Figure 3, the heights Hb of the microprotrusions 24A and 24B relative to the base portion 22 may be equal. Alternatively, the height Hb of the microprotrusions 24 relative to the base portion 22 may be 0.1 mm or more and 1.0 mm or less, and the spacing P between adjacent microprotrusions 24 may be 0.1 mm or more and 1.0 mm or less.

[0027] (action) This embodiment is configured as described above, and its operation will be explained below. In Figure 1, in the tire 10 according to this embodiment, minute protrusions 24 are formed on the base portion 22 and the raised portion 23. Specifically, minute protrusions 24A are formed on the base portion 22 and minute protrusions 24B are formed on the raised portion 23, so that the reflection of light incident on the pattern region 20 is suppressed compared to the outside of the pattern region 20, while a difference in the way light is reflected is made between the base portion 22 side and the raised portion 23 side within the pattern region 20. If the density of minute protrusions 24B on the raised portion 23 is greater than the density of minute protrusions 24A on the base portion 22, the reflection of light on the base portion 22 side is further suppressed, while the reflection of light on the raised portion 23 side is allowed, thereby further differentiating the way light is reflected. The same applies when the width W2 of the tip of the minute protrusion 24B on the raised portion 23 is greater than the width W1 of the tip of the minute protrusion 24A on the base portion 22.

[0028] When the heights Hb of the micro-protrusions 24 are equal relative to the base portion 22, the depth from the tip of the micro-protrusion 24 to the base portion 22 is greater than the depth from the tip of the micro-protrusion 24 to the raised portion 23. Therefore, light reflection on the base portion 22 side of the pattern region 20 can be suppressed more than on the raised portion 23 side.

[0029] By appropriately setting the height Hb of the microprotrusions 24 and the spacing P between the microprotrusions 24, it is possible to produce contrast due to differences in light reflection.

[0030] Thus, according to this embodiment, it is possible to enable richer expression in the pattern area 20 on the outer surface of the tire 10.

[0031] [Second Embodiment] In Figures 5 to 8, in the tire 10 according to this embodiment, the decorative part 14 is arc-shaped when viewed from the axial direction of the tire 10 and is positioned at any position in the circumferential direction of the tire.

[0032] The tire sidewall portion 12, excluding the decorative portion 14, is smooth, just like a normal tire. The base portion 22 is the smoothed portion of the tire sidewall portion 12.

[0033] The decorative section 14 is composed of a plurality of first pattern areas 120 and second pattern areas 122 of different sizes and orientations. The first pattern areas 120 and the second pattern areas 122 are demarcated by the base section 22 over substantially the entire area of ​​the decorative section 14.

[0034] Since the first pattern region 120 and the second pattern region 122 have the same contour shape in plan view, differing only in orientation, we will describe the shape of the first pattern region 120 as a representative example.

[0035] As shown in Figure 6, the first pattern region 120 has a shape composed of a pair of opposing arc recesses (convex inward) 124 and a pair of opposing arc protrusions (convex outward) 126 formed on both sides of the pair of arc recesses 124.

[0036] As shown in Figure 5, the first pattern region 120 and the second pattern region 122, both of the same size, are alternately arranged at intervals along a line TL in the circumferential direction of the tire, with their orientations rotated by 90° from each other. The line TL is inclined at an angle θ with respect to the radial direction of the tire (direction of arrow R).

[0037] Furthermore, the size of the first pattern region 120 and the second pattern region 122 increases as they are positioned on the clockwise side (arrow CW direction side), which is one side of the tire circumferential direction. In this embodiment, the first pattern region 120 and the second pattern region 122 positioned on the other line TL' positioned on the clockwise side are larger than the first pattern region 120 and the second pattern region 122 positioned on line TL.

[0038] In this embodiment, exceptionally, on the clockwise side of the decorative portion 14, some of the first pattern region 120 and the second pattern region 122 are in contact with each other without the base portion 22 in between.

[0039] The first pattern area 120 has a lower brightness (L*) compared to the base area 22 and appears black compared to the base area 22. The second pattern area 122 has a higher brightness than the first pattern area 120 and a lower brightness than the base area 22. In other words, the brightness decreases in the order of base area 22, second pattern area 122, and first pattern area 120. The second pattern area 122 appears blacker than the base area 22, the first pattern area 120 appears blacker than the second pattern area 122, and the first pattern area 120 appears the blackest.

[0040] Furthermore, in the mold for forming the tire 10, by providing minute irregularities in the parts corresponding to the first pattern area 120 and the second pattern area 122, the first pattern area 120 and the second pattern area 122 can be formed on the surface of the tire side portion 12.

[0041] In the first pattern region 120 and the second pattern region 122, minute protrusions are formed that extend from the base portion 22, resulting in uneven surfaces in the first pattern region 120 and the second pattern region 122. Although not shown in the figures, the first pattern region 120 and the second pattern region 122 are provided with raised base portions.

[0042] As shown in Figure 7, in the first pattern region 120 and the second pattern region 122, a first asterisk projection 34 and a second asterisk projection 36, which are examples of micro-protrusions, are formed similarly to each other.

[0043] The shapes of the first asterisk projection 34 and the second asterisk projection 36 are similar within their respective regions. Furthermore, the distance P between adjacent first asterisk projections 34 and second asterisk projections 36 varies according to the similarity ratio.

[0044] As described above, the shapes of the first asterisk projection 34 and the second asterisk projection 36 are similar in their respective regions. Therefore, the shapes of the first asterisk projection 34 and the second asterisk projection 36 will be explained below using the first pattern region 120 as an example.

[0045] (First pattern area 120) As shown in Figure 7(A), the first pattern region 120 has a plurality of first asterisk protrusions 34 and a plurality of second asterisk protrusions 36 that protrude from the base portion 22. The first asterisk protrusions 34 and the second asterisk protrusions 36 are arranged alternately in the tire circumferential direction and the tire radial direction.

[0046] (First asterisk projection 34) As shown in Figure 7(A), the first asterisk projection 34 has multiple extensions 34E, each extending in a different direction from the center O1 which serves as the base point, when viewed from a direction perpendicular to the base portion 22 (the rotation axis direction of the tire 10). In this embodiment, there are six extensions 34E.

[0047] The six extensions 34E are each at a 60° angle to adjacent extensions 34E. In other words, the first asterisk projection 34 has a shape in which six extensions 34E radiate outwards from the center O1. The extensions 34E of the first asterisk projection 34 and the extensions of the adjacent second asterisk projection 36 are connected by a connecting portion 38.

[0048] As shown in Figure 8, in the extension portion 34E of the first asterisk projection 34, the cross-section in the direction perpendicular to the extension direction is a roughly isosceles triangle with a flat top surface 34C. In other words, the first asterisk projection 34 has a top surface 34C and a pair of side surfaces 34D. In this embodiment, the width of the top surface 34C (W1 in the figure) is 0.02 [mm], and the apex angle of the first asterisk projection 34 (D1 in the figure) is 26 [degrees]. The height of the first asterisk projection 34 (H1 in the figure) is a predetermined value between 0.05 [mm] and 1.0 [mm]. If the height of the projection (projection height) is less than 0.05 [mm], it becomes difficult to form the projection, and there is a risk that the brightness cannot be reduced to the point where it appears black by attenuating the incident light. Furthermore, by making the height of the protrusions 1.0 mm or less, the difference in rigidity between the protrusions and the surrounding areas is reduced, thereby suppressing localized stress concentration.

[0049] In this embodiment, dimensions such as the height of the protrusions and the spacing P (pitch) between the protrusions, which will be described later, can be measured, for example, using the VR-3000 series one-shot 3D shape measuring machine from Keyence Corporation.

[0050] (Second asterisk projection 36) As shown in Figure 7(A), the second asterisk projection 36 has the same shape as the first asterisk projection 34. Specifically, the second asterisk projection 36 is shaped by rotating the first asterisk projection 34 clockwise by 90 degrees around the center O1 when viewed from a direction perpendicular to the base portion 22, and then inverting the top and bottom of the first asterisk projection 34 that has been rotated by 90 degrees around the center O1. That is, the second asterisk projection 36 has six extensions 36E extending in different directions from the center O2 which serves as the base point, and each extension 36E has a top surface 36C and a side surface 36D.

[0051] The first asterisk projection 34 and the second asterisk projection 36 are arranged alternately in the circumferential and radial directions of the tire, filling the entire area of ​​each region.

[0052] Furthermore, for adjacent first asterisk protrusions 34 and second asterisk protrusions 36 in the tire radial and circumferential directions, the distance P between the centers O1 and O2 is set to a predetermined value of 0.1 mm or more and 1.0 mm or less. If the distance P is less than 0.1 mm, it becomes difficult to form the protrusions. Moreover, if the distance P is greater than 1.0 mm, there is a risk that the brightness cannot be reduced to the point where it appears black by attenuating the incident light.

[0053] (Second pattern area 122) Next, we will explain the second pattern region 122.

[0054] As shown in Figure 7(B), the second pattern region 122 has first asterisk protrusions 34 and second asterisk protrusions 36 that are similar in shape to those in the first pattern region 120, but the density of the protrusions is lower than that of the protrusions formed in the first pattern region 120. As a result, the second pattern region 122 appears relatively brighter than the first pattern region 120.

[0055] Furthermore, it is preferable that the first pattern region 120 and the second pattern region 122 be arranged in three or more locations, and more preferably five or more locations, in the circumferential direction of the tire.

[0056] (action) In other areas of the tire side portion 12 where no protrusions are formed, namely the base portion 22, the incident light is reflected outward by the smooth outer surface that makes up the base portion 22.

[0057] In contrast, in the first pattern region 120 and the second pattern region 122, the light incident on the first asterisk projection 34 and the second asterisk projection 36 strikes the sides 34D and 36D shown in Figure 8. The incident light is then attenuated by repeatedly reflecting between the opposing sides 34D and 36D and reflected outwards. Therefore, the first pattern region 120 and the second pattern region 122 appear darker compared to the base portion 22.

[0058] Furthermore, since the apex angles of each protrusion are similar, the area occupied per unit area by the base portion 22 of the second pattern region 122 is larger than the area occupied per unit area by the base portion 22 of the first pattern region 120.

[0059] As a result, the amount of light reflected outward in the second pattern region 122 is greater than the amount of light reflected outward in the first pattern region 120. In other words, the brightness of the second pattern region 122 is higher than that of the first pattern region 120. To put it another way, the second pattern region 122 appears relatively brighter than the first pattern region 120, and the first pattern region 120 appears relatively darker than the second pattern region 122.

[0060] As described above, the decorative section 14 of this embodiment is provided with a plurality of first pattern areas 120 and a plurality of second pattern areas 122 that are arranged adjacent to the first pattern areas 120 and have a higher brightness than the first pattern areas 120, and the areas of the first pattern areas 120 and the second pattern areas 122 increase in a clockwise direction. For this reason, compared to decorative sections that are not configured in this way, the decorative section 14 of this embodiment can greatly broaden the range of expression, and when viewing the decorative section 14, the viewer's gaze can be guided in a clockwise direction.

[0061] Furthermore, since the extensions of the first asterisk projection 34 and the second asterisk projection 36 are connected by a connecting portion 38, the first asterisk projection 34 and the second asterisk projection 36 support each other via the connecting portion 38, thereby suppressing the collapse of the first asterisk projection 34 and the second asterisk projection 36. This improves durability.

[0062] In the above embodiment, the decorative section 14 had two pattern areas with different brightness levels, but it may also have three or more pattern areas with different brightness levels.

[0063] [Other embodiments] Although an example of an embodiment of the present invention has been described above, the embodiments of the present invention are not limited to those described above, and it goes without saying that various modifications can be made and implemented without departing from the spirit of the invention. [Explanation of symbols]

[0064] 10...Tire, 12...Tire side section, 20...Pattern area, 22...Base section, 23...Raised bottom section, 24...Micro-protrusion, 34...First asterisk protrusion (micro-protrusion), 34C...Top surface, 34D...Side surface, 34E...Extension section, 36...Second asterisk protrusion (micro-protrusion), 120...First pattern area (pattern area), 122...Second pattern area (pattern area), Hb...Height of micro-protrusion relative to the base section, P...Spacing

Claims

1. A pattern region formed on the outer surface of the tire, having a base portion, A raised bottom portion is provided in the pattern region and is raised from the base portion, The base portion and the raised portion each have minute protrusions formed thereon, A tire in which the density of the minute protrusions in the base portion is greater than the density of the minute protrusions in the raised portion.

2. The tire according to claim 1, wherein the heights of the minute protrusions are equal to each other with respect to the base portion.

3. The height of the minute protrusions relative to the base portion is 0.1 mm or more and 1.0 mm or less. The tire according to claim 1, wherein the spacing between adjacent minute protrusions is 0.1 mm or more and 1.0 mm or less.

4. The aforementioned minute protrusions include extensions that extend in multiple directions from the base point in a plan view, The tire according to claim 3, wherein the extension portion of one of the aforementioned minute protrusions and the extension portion of another adjacent minute protrusion are connected by a connecting portion.

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