阅读说明：本技术 轮胎 (Tyre for vehicle wheels ) 是由 荻原佐和 于 2019-05-07 设计创作，主要内容包括：提供轮胎,同时实现轮胎的外观的提高和硫化模具的清洁的作业效率的提高。轮胎(1)在胎侧部(3)的表面(5)上形成有装饰图案(7)。在装饰图案(7)中,沿轮胎径向延伸的多个脊(11)以隔开间隙(12)的方式在轮胎周向上排列。脊(11)的横截面呈随着远离表面(5),沿表面(5)的长度(L1)逐渐减小的锥状。装饰图案(7)构成为满足下式(1)和(2),20≤A≤40…(1)0.15≤C≤0.25…(2)其中,A是脊(11)的锥角(度),C是沿表面(5)测定的间隙(12)的最小长度(mm)。(Provided is a tire, which can improve the appearance of the tire and the working efficiency of cleaning a vulcanization mold at the same time. A decorative pattern (7) is formed on the surface (5) of the side wall part (3) of the tire (1). In the decorative pattern (7), a plurality of ridges (11) extending in the tire radial direction are arranged in the tire circumferential direction with a gap (12) therebetween. The ridges (11) are tapered in cross-section progressively decreasing away from the surface (5) along the length (L1) of the surface (5). The decorative pattern (7) is configured to satisfy the following formulas (1) and (2), 20 & ltA & lt 40 … (1)0.15 & ltC & lt 0.25 … (2) wherein A is the taper angle (degree) of the ridge (11) and C is the minimum length (mm) of the gap (12) measured along the surface (5).)

1. A tire, a decorative pattern is formed on the surface of a sidewall,

in the decorative pattern, a plurality of ridges extending in the tire radial direction are arranged in the tire circumferential direction with a gap therebetween,

the ridges having a cross-sectional shape tapering progressively less along the length of the surface as one moves away from the surface,

the decorative pattern is configured to satisfy the following formulas (1) and (2),

20≤A≤40…(1)

0.15≤C≤0.25…(2)

where A is the taper angle of the ridge in degrees and C is the minimum length of the gap measured along the surface in millimeters.

2. The tire according to claim 1, wherein,

the ridge has a cross-section with an upper base extending along the surface at a position furthest from the surface,

the decorative pattern is configured to also satisfy the following formulas (3) and (4),

0.2≤C/D≤0.4…(3)

1≤B/C≤3…(4)

wherein B is a length of the upper sole measured along the surface, and the length is in units of millimeters, and D is an arrangement interval of the ridges in the tire circumferential direction, and the arrangement interval is in units of millimeters.

3. The tire according to claim 2, wherein,

the arrangement interval D of the ridges is 0.13mm to 2.1 mm.

4. The tire according to claim 2 or 3,

the length B of the upper bottom is 0.05 mm-0.4 mm.

5. The tire according to claim 1, wherein,

the ridges have a cross-section in the form of a triangle having a vertex at a position furthest from the surface,

the decorative pattern is configured to also satisfy the following formula (5),

0.2≤C/D≤0.4…(5)

wherein D is an arrangement interval of the ridges in the tire circumferential direction.

6. The tire according to claim 5,

one of a pair of side surfaces extending from the apex toward the surface is perpendicular to the surface.

7. Tire according to any one of claims 1 to 6,

the height of the ridge from the surface is 0.1 mm-0.5 mm.

Technical Field

The present invention relates to a tire having a decorative pattern formed on a surface of a sidewall.

Background

In general, since the thickness of rubber is thin, the side wall portion of the tire tends to be conspicuous by the seams of the carcass, which is an internal structural member, residual air, and the like, and irregularities called dimples and bumps. Such unevenness deteriorates the appearance of the tire.

Patent document 1 below proposes a tire having a belt-like design in which a plurality of ridges are arranged at predetermined intervals on the surface of a sidewall in order to make unevenness less noticeable. Such a belt-like design is formed by using a groove portion (reverse stripe of a ridge) formed on a molding surface of a vulcanization mold of a tire.

Patent document 1: japanese laid-open patent publication No. H07-164831

In addition, in order to make the unevenness less noticeable, it is important to make the gaps between adjacent ridges small so that the portions are visually recognized as dark (black), and to make the contrast of the light of the band-shaped design clear.

However, if the gap between adjacent ridges is made small, a large number of ridges are formed in the tire circumferential direction, and accordingly, the proportion of the groove portion formed in the molding surface on the vulcanizing mold side becomes large. There are the following problems: the laser beam and the granular material used for cleaning the molding surface are hard to contact the groove portion, and therefore the efficiency of the cleaning operation of the vulcanizing mold is reduced. Therefore, there is room for further improvement in achieving both improvement in the appearance of the tire and improvement in the efficiency of the cleaning operation of the vulcanizing mold.

Disclosure of Invention

The present invention has been made in view of the above circumstances, and a main object thereof is to provide a tire capable of improving both the appearance of the tire and the working efficiency of cleaning the vulcanizing mold.

The present invention is a tire having a decorative pattern formed on a surface of a sidewall portion, wherein a plurality of ridges extending in a tire radial direction are arranged in a tire circumferential direction with a gap therebetween, the ridges have a tapered shape whose cross section gradually decreases along a length of the surface as the ridges are separated from the surface, and the decorative pattern satisfies the following expressions (1) and (2),

20≤A≤40…(1)

0.15≤C≤0.25…(2)

where A is the taper angle (degrees) of the ridge and C is the minimum length (mm) of the gap measured along the surface.

In the tire of the present invention, the cross section of the ridge may have an upper base extending along the surface at a position farthest from the surface, and the decorative pattern may be configured to further satisfy the following formulas (3) and (4),

0.2≤C/D≤0.4…(3)

1≤B/C≤3…(4)

wherein B is a length (mm) of the upper bottom measured along the surface, and D is an arrangement interval (mm) of the ridges in the tire circumferential direction.

In the tire of the present invention, the ridge disposition interval D may be 0.13mm to 2.1 mm.

In the tire of the present invention, the length B of the upper base may be 0.05mm to 0.4 mm.

In the tire of the present invention, the cross section of the ridge may be a triangle having a vertex at a position farthest from the surface, the decorative pattern may be configured to satisfy also the following formula (5),

0.2≤C/D≤0.4…(5)

wherein D is an arrangement interval of the ridges in the tire circumferential direction.

In the tire of the present invention, one of a pair of side surfaces extending from the apex toward the surface may be perpendicular to the surface.

In the tire of the present invention, the height of the ridge from the surface may be 0.1mm to 0.5 mm.

The tire of the present invention has a decorative pattern formed on the surface of the sidewall portion. In the decorative pattern, a plurality of ridges extending in the tire radial direction are arranged in the tire circumferential direction with a gap therebetween. Such a decorative pattern can make the unevenness appearing at the sidewall portion inconspicuous, and can improve the appearance of the tire.

The ridge has a cross-sectional shape that gradually decreases along the length of the surface as it goes away from the surface, and the decorative pattern is configured to satisfy the following formulas (1) and (2),

20≤A≤40…(1)

0.15≤C≤0.25…(2)

where A is the taper angle (degrees) of the ridge and C is the minimum length (mm) of the gap measured along the surface.

The ridge of the decorative pattern has a taper angle a of 40 degrees or less, and thus an incident angle and a reflection angle of light incident perpendicular to the surface on the side of the ridge become small. Thereby, the decorative pattern attenuates reflection from the side surface toward the outer side of the tire. In addition, since the minimum length C of the gap of the decorative pattern is 0.25mm or less, reflection from the surface toward the outer side of the tire can be reduced. Thus, the decorative pattern makes the gap appear darker (black), and the contrast between the ridge and the gap can be made clear, so that the unevenness can be further made inconspicuous.

On the other hand, since the taper angle a of the decorative pattern is 20 degrees or more, the wall surface of the groove portion (reverse stripe of the ridge) of the vulcanizing mold for forming the ridge can be appropriately expanded. Therefore, the laser, the granular material, and the like can easily reach the groove portion during the die cleaning. Further, since the minimum length C of the gap of the decorative pattern is 0.15mm or more, the number of ridges can be prevented from excessively increasing in the tire circumferential direction. Thus, in the present invention, the ratio of the groove portions is reduced, and the efficiency of the cleaning work of the vulcanizing mold can be improved while the unevenness is made inconspicuous.

Drawings

Fig. 1 is a partial side view showing an example of a tire.

Fig. 2 is a sectional view taken along line a-a of fig. 1.

Fig. 3 is a partial cross-sectional view showing an example of a vulcanizing mold and a green tire in a vulcanizing process.

Fig. 4 is a cross-sectional view showing an example of a decorative pattern according to another embodiment of the present invention.

Fig. 5 is a partial cross-sectional view showing an example of a vulcanizing mold and a green tire in a vulcanizing process according to another embodiment of the present invention.

Description of the reference symbols

3: a sidewall portion; 7: decorating the pattern; 11: a ridge; 12: a gap.

Detailed Description

Hereinafter, one embodiment of the present invention will be described with reference to the drawings.

Fig. 1 is a partial side view showing an example of a tire. The tire 1 of the present embodiment includes: a tread portion 2; a pair of sidewall portions 3 extending inward in the tire radial direction from both sides of the tread portion 2; and a bead portion 4 that is continuous with the inner side of the sidewall portion 3 in the tire radial direction. In the present embodiment, the tire 1 for a passenger vehicle is exemplified, but the present invention is not limited to this embodiment, and may be a tire for a motorcycle or a heavy load, for example.

In the present specification, unless otherwise specified, the dimensions and the like of each part of the tire 1 are values measured in a state (standard state) in which the tire 1 is assembled to a regular rim (not shown) and is loaded with a regular internal pressure and in a no-load state.

The "regular Rim" refers to a Rim specified for each tire in a specification system including a specification under which the tire is based, and is, for example, "standard Rim" in the case of JATMA, "Design Rim (Design Rim)" in the case of TRA, or "measurement Rim (Measuring Rim)" in the case of ETRTO.

The "normal internal PRESSURE" is an air PRESSURE specified for each TIRE in the specification, and is a "maximum air PRESSURE" in the case of JATMA, a maximum value described in a table "TIRE LOAD conditions AT variaus color INFLATION PRESSUREs" in the case of TRA, an "INFLATION PRESSURE" in the case of ETRTO, and 180kPa in the case of a passenger vehicle TIRE.

The tire 1 of the present embodiment has a decorative pattern 7 formed on the surface 5 of the sidewall 3. The decorative pattern 7 of the present embodiment is formed in a ring shape when the tire 1 is viewed from the side, but is not limited to this form. The decorative pattern 7 may be formed in a band shape in which both ends in the tire circumferential direction are interrupted, or may be provided separately in the tire circumferential direction. Further, characters (not shown) indicating a brand mark, a brand name, and the like of the tire 1 may be formed in relief on the decorative pattern 7. The length L1 of the decorative pattern 7 in the tire radial direction is not particularly limited. The length L1 of the present embodiment is preferably about 5% to 30% of the tire section height.

Fig. 2 is a sectional view a-a of fig. 1. Fig. 3 is a partial cross-sectional view showing an example of the pattern forming portion 24 formed in the vulcanizing mold 21. As shown in fig. 2, the decorative pattern 7 is formed by arranging a plurality of ridges 11 extending in the tire radial direction with a gap 12 in the tire circumferential direction. As in the conventional art, the decorative pattern 7 is formed by a groove portion (inverted pattern of the ridge 11) 25 of a pattern forming portion 24 provided on a molding surface 23 of a vulcanization mold 21 of the tire shown in fig. 3.

As shown in fig. 1 and 2, the ridges 11 protrude from the surface 5 of the sidewall 3 and are formed as ridge-like projections extending in the tire radial direction. As shown in fig. 2, the cross section of the ridge 11 is formed in a tapered shape that gradually decreases along the length L2 of the surface 5 as it goes away from the surface 5 of the sidewall portion 3.

The cross-section of the ridge 11 of this embodiment has an upper base 15 extending along the surface 5 at a position furthest from the surface 5. The ridge 11 is thus formed in cross-section as a trapezoid having an upper base 15 and a pair of side surfaces 16, 16 extending from the upper base 15 towards the surface 5. In the drawings, each corner 17 of the ridge 11 is drawn with a sharp edge, but the "trapezoidal shape" includes a form in which a chamfer having a small radius of curvature is formed in the corner 17 in consideration of the size of the ridge 11 and the molding technique of the rubber.

Such a decorative pattern 7 allows the gap 12 between the adjacent ridges 11, 11 to be visually recognized as dark (black), and can make the contrast of light between the ridge 11 and the gap 12 clear. As a result, the decorative pattern 7 can exhibit a masking effect of making the unevenness (dents and projections) due to the seams of the carcass (not shown) as an internal structural member of the tire 1, residual air, and the like inconspicuous, and thus contributes to improving the appearance of the tire 1.

The decorative pattern 7 (shown in fig. 2) of the present embodiment is configured to satisfy the following expressions (1) and (2).

20≤A≤40…(1)

0.15≤C≤0.25…(2)

Where A is the taper angle (degree) of the ridge 11 and C is the minimum length (mm) of the gap 12 as measured along the surface 5.

According to the above formula (1), the taper angle a of the ridge 11 is set to 40 degrees or less. In general, in order to improve the appearance of the sidewall portion 3 of the tire 1, the appearance of the tire 1 when viewed from the front is particularly important. In the decorative pattern of the present embodiment, by setting the taper angle a of the ridge 11 to 40 degrees or less, the incident angle θ 1 and the reflection angle θ 2 of the light 30 (shown by a two-dot chain line in fig. 2) incident perpendicularly to the surface 5 of the sidewall portion 3 (in the tire axial direction) on the side surface 16 of the ridge 11 can be made small. Therefore, the decorative pattern 7 can attenuate reflection from the side surface 16 of the ridge 11 toward the outer side of the tire 1.

In addition, the wall surfaces 28 and 28 of the groove portion 25 of the vulcanizing mold 21 for forming the ridge 11 shown in fig. 3 (i.e., the side surface forming portions for forming the side surfaces 16 of the ridge 11) can be made smaller in the incident angle and the reflection angle of the laser beam and the particulate body used for cleaning the vulcanizing mold 21. This allows the laser beam and the granular material to be diffusely reflected in the groove portion 25, thereby efficiently removing dirt adhering to the groove 25.

According to the above formula (2), the minimum length C of the gap 12 is set to 0.25mm or less. Thus, in the decorative pattern 7 of the present embodiment, reflection from the surface 5 of the sidewall portion 3 toward the outside of the tire 1 can be reduced. Thus, the decorative pattern 7 of the present embodiment makes the gap 12 appear darker (black), and the contrast between the light of the ridge 11 and the light of the gap 12 can be made clear. Therefore, the decorative pattern 7 can further make the unevenness (not shown) formed in the sidewall portion 3 less conspicuous, and can improve the appearance of the tire 1.

On the other hand, if the taper angle a of the ridge 11 and the minimum length C of the gap 12 are made small, a large number of ridges 11 are formed in the tire circumferential direction, and accordingly, the ratio (number) of the groove portions 25 formed on the molding surface 23 of the vulcanizing mold 21 shown in fig. 3 also becomes large. Since the groove portion 25 is hard to contact with the laser beam, the granular material, or the like used for cleaning the molding surface 23, the efficiency of the cleaning operation of the vulcanizing mold is reduced.

In the present embodiment, the taper angle a is set to 20 degrees or more according to the above formula (1). As a result, as shown in fig. 3, in the present embodiment, at least one (both in the present embodiment) of the wall surfaces 28, 28 of the groove portion 25 of the vulcanizing mold 21 for forming the ridge 11 can be appropriately expanded in the tire circumferential direction. Therefore, in the present embodiment, the laser beam, the granular material, and the like can easily reach the groove portion 25 of the vulcanizing mold 21 during mold cleaning.

Further, according to the above expression (2), the minimum length C of the gap 12 is set to 0.15mm or more. Thus, the decorative pattern 7 of the present embodiment can prevent the number of ridges 11 from increasing excessively in the tire circumferential direction. Thus, in the present embodiment, the ratio of the groove portion 25 of the vulcanizing mold 21 can be made small, and the efficiency of the cleaning operation can be improved.

As described above, in the tire 1 of the present embodiment, the decorative pattern 7 satisfies the above expressions (1) and (2), and thereby the improvement of the appearance of the tire 1 and the improvement of the work efficiency of cleaning the vulcanizing mold 21 can be achieved at the same time.

In addition, if the taper angle a exceeds 40 degrees, the incident angle θ 1 and the reflection angle θ 2 of the light 30 on the side face 16 of the ridge 11 described above become large. Therefore, reflection from the side surface 16 toward the outer side of the tire 1 may not be reduced. Further, on the wall surfaces 28 and 28 of the groove portion 25 of the vulcanizing mold 21 for forming the ridge 11 shown in fig. 3, the incident angle and the reflection angle of the laser beam and the granular material used for cleaning the vulcanizing mold 21 are also increased, and there is a possibility that the dirt adhering to the groove 25 cannot be removed efficiently.

On the other hand, if the taper angle a is less than 20 degrees, the wall surfaces 28, 28 of the groove portion 25 cannot be expanded, and the efficiency of the cleaning operation may be reduced in the mold cleaning. Further, since the wall surfaces 28, 28 of the groove portion 25 intersect the bottom surface 27 of the upper bottom 15 for forming the ridge 11 at a large angle, the workability of the groove portion 25 is lowered, and there is a possibility that the processing cost of the pattern forming portion 24 is increased. From such a viewpoint, the taper angle a is preferably 25 degrees or more, and preferably 35 degrees or less.

In addition, if the minimum length C of the gap 12 exceeds 0.25mm, the reflection from the surface 5 of the sidewall portion 3 toward the outer side of the tire 1 increases. Therefore, the contrast of light between the ridge 11 and the gap 12 cannot be made clear, and the appearance of the tire 1 may be degraded. On the other hand, if the minimum length C of the gap 12 is less than 0.15mm, the ratio of the groove portion 25 of the vulcanizing mold 21 shown in fig. 3 becomes large, and there is a possibility that the efficiency of the cleaning work may be lowered at the time of mold cleaning. Further, the width of the molding surface 23 between the adjacent groove portions 25, 25 may be reduced, which may lead to an increase in the processing cost of the pattern forming portion 24 and early wear of the molding surface 23 due to cleaning. From such a viewpoint, the minimum length C of the gap 12 is preferably 0.18mm or more, and preferably 0.22mm or less.

In order to further enhance the contrast of light between the ridges 11 and the gaps 12 and to make it easier for laser light, particles, and the like to reach the grooves 25, the decorative pattern 7 of the present embodiment is preferably configured to satisfy the above expressions (1) and (2) and also satisfy the following expressions (3) and (4).

0.2≤C/D≤0.4…(3)

1≤B/C≤3…(4)

Where B is the length of the upper bottom 15 measured along the surface 5, and D is the arrangement interval of the ridges 11 in the tire circumferential direction.

According to the above equation (3), the ratio C/D of the minimum length C of the gap 12 to the arrangement interval D of the ridges 11 shown in fig. 2 is set to 0.4 or less. Thus, the minimum length C of the gap 12 is sufficiently small with respect to the arrangement interval D of the ridges 11, and reflection from the surface 5 of the sidewall 3 toward the outside of the tire 1 can be further reduced.

According to the above formula (4), the ratio B/C of the length B of the upper bottom 15 to the minimum length C of the gap 12 is set to 3 or less. This prevents the upper bottom 15 from being formed excessively large relative to the gap 12 (surface 5). Therefore, the decorative pattern 7 can uniformly form the upper bottom 15 which is visually recognized as bright (white) and the gap 12 which is visually recognized as dark (black), and therefore the contrast of light between the ridges 11 and the gap 12 can be further enhanced, and the appearance of the tire 1 can be further improved.

Further, according to the above formula (3), the ratio C/D of the minimum length C of the gap 12 to the arrangement interval D of the ridges 11 is set to 0.2 or more. This can increase the width of the molding surface 23 between the adjacent groove portions 25, and can effectively prevent an increase in the processing cost of the pattern forming portion 24 and an early decrease in the molding surface 23 due to cleaning.

According to the above formula (4), the ratio B/C of the length B of the upper bottom 15 to the minimum length C of the gap 12 is set to 1 or more. Thus, in the present embodiment, the length of the bottom surface 27 of the groove portion 25 of the vulcanizing mold 21 can be increased in the tire circumferential direction. Therefore, in the present embodiment, the laser beam, the granular material, and the like can be more easily caused to reach the groove portion 25 during the cleaning of the mold.

As described above, by satisfying the above expressions (1) and (2) and satisfying the above expressions (3) and (4) in addition to the decorative pattern 7 of the present embodiment, it is possible to achieve both improvement in the appearance of the tire 1 and improvement in the work efficiency of cleaning the vulcanizing mold 21 at a higher level.

In addition, if the ratio C/D of the minimum length C of the gap 12 to the arrangement interval D of the ridges 11 exceeds 0.4, the minimum length C of the gap 12 is formed to be large with respect to the arrangement interval D of the ridges 11. Therefore, reflection from the surface 5 of the sidewall portion 3 toward the outside of the tire 1 may not be sufficiently reduced. On the other hand, if the ratio C/D is less than 0.2, the width of the molding surface 23 between the adjacent groove portions 25, 25 may be reduced, and it may be impossible to sufficiently prevent an increase in processing cost of the pattern forming portion 24 and an early decrease in abrasion of the molding surface 23 due to cleaning. From such a viewpoint, the ratio C/D is preferably 0.25 or more, and preferably 0.35 or less.

Further, if the ratio B/C of the length B of the upper sole 15 to the minimum length C of the gap 12 exceeds 3, the upper sole 15 becomes larger in the tire circumferential direction than the gap 12 shown in fig. 2, and there is a possibility that the contrast of light between the ridge 11 and the gap 12 cannot be sufficiently enhanced. On the other hand, if the ratio B/C is less than 1, the bottom surface 27 of the groove portion 25 of the vulcanization mold 21 shown in fig. 3 becomes small, and there is a possibility that the laser beam, the granular material, or the like cannot easily reach the inside of the groove portion 25. Also, the processing cost of the pattern forming portion 24 may increase. From such a viewpoint, the ratio B/C is preferably 1.5 or more, and preferably 2.5 or less.

The arrangement interval D of the ridges 11 may be appropriately set as long as it satisfies the above expression (3), but is preferably set to 0.13mm to 2.1 mm. By setting the arrangement interval D to 0.13mm or more, the number of ridges 11 can be prevented from increasing, and the ratio of the groove portions 25 of the vulcanizing mold 21 can be made small. Therefore, the cleaning work efficiency can be further improved when the mold is cleaned.

In addition, by setting the arrangement interval D to 2.1mm or less, at least one of the upper bottom 15 and the gap 12 shown in fig. 2 can be prevented from becoming large, and therefore the contrast between the ridge 11 and the gap 12 can be further enhanced. From such a viewpoint, the arrangement interval D is more preferably 0.3mm or more, and more preferably 1.9mm or less.

The length B of the upper bottom 15 can be appropriately set as long as it satisfies the above formula (4), but is more preferably set to 0.05mm to 0.40 mm. By setting the length B of the upper bottom 15 to 0.05mm or more, the bottom surface 27 of the groove portion 25 of the vulcanizing mold 21 shown in fig. 3 can be formed large, and the work efficiency of cleaning can be further improved at the time of mold cleaning.

Further, the upper bottom 15 and the gap 12 shown in fig. 2 are formed in a balanced manner by setting the length B of the upper bottom 15 to 0.40mm or less, and therefore the contrast of light between the ridge 11 and the gap 12 can be further enhanced. From such a viewpoint, the length B of the upper sole 15 is more preferably 0.10mm or more, and more preferably 0.35mm or less.

The height E of the ridge 11 of the sidewall portion 3 from the surface 5 can be set as appropriate, but is preferably set to 0.1mm to 0.5 mm. By setting the height E of the ridge 11 to 0.1mm or more, the gap 12 can be made darker (black) as viewed. Further, by setting the height E of the ridge 11 to 0.5mm or less, the groove portion 25 of the vulcanizing mold 21 shown in fig. 3 can be prevented from being formed deep, and therefore the working efficiency of cleaning can be further improved. From such a viewpoint, the height E is more preferably 0.15mm or more, and more preferably 0.45mm or less.

The cross section of the ridge 11 of the present embodiment has a trapezoidal shape having the upper bottom 15, but the present invention is not limited to this. Fig. 4 is a cross-sectional view showing an example of the decorative pattern 7 according to another embodiment of the present invention. Fig. 5 is a partial cross-sectional view showing an example of the pattern forming section 24 according to another embodiment of the present invention. In this embodiment, the same components as those in the previous embodiments are denoted by the same reference numerals, and the description thereof may be omitted.

The ridge 11 of this embodiment is formed in a triangular shape in cross section having an apex 35 at a position farthest from the surface 5 of the sidewall portion 3. In addition, the cross-section of the ridge 11 has a pair of sides 16, 16 extending from the apex 35 to the surface 5. The "triangular shape" includes a case where a minute chamfer is formed at a part of the apex 35 of the triangle in consideration of the size of the ridge 11 and the molding technique of rubber.

The decorative pattern 7 of this embodiment can exhibit a masking effect in which the unevenness (not shown) formed in the sidewall portion 3 is less noticeable, as with the decorative pattern 7 of the previous embodiment. In the decorative pattern 7 of this embodiment, since the cross section of the ridge 11 is formed in a triangular shape, the apex 35 of each ridge 11 can be formed to be sharp, and a good appearance can be obtained. Therefore, the decorative pattern 7 contributes to improving the appearance of the tire 1.

The decorative pattern 7 of this embodiment is configured such that the taper angle a of the ridge 11 and the minimum length C of the gap 12 satisfy the above equations (1) and (2). Thus, the decorative pattern 7 of this embodiment can simultaneously improve the appearance of the tire 1 and the work efficiency of cleaning the vulcanizing mold 21 shown in fig. 5, similarly to the decorative pattern 7 of the previous embodiment. The preferred ranges of the taper angle a and the minimum length C are the same as those of the previous embodiment.

The decorative pattern of this embodiment is configured to satisfy the above expressions (1) and (2), and also satisfy the following expression (5).

0.2≤C/D≤0.4…(5)

Where D is the arrangement interval of the ridges 11 in the tire circumferential direction.

The above equation (5) defines the range of the ratio C/D of the minimum length C of the gap 12 to the arrangement interval D of the ridges 11, as in the above equation (3) of the previous embodiment. This can further enhance the contrast of light between the ridge 11 and the gap 12, and make it easier for laser light, particles, and the like to reach the groove 25.

As described above, by satisfying the above expressions (1) and (2) and satisfying the above expression (5) in the decorative pattern 7 of the present embodiment, it is possible to achieve both improvement in the appearance of the tire 1 and improvement in the work efficiency of cleaning the vulcanization mold 21 at a higher level. The preferred ranges of the ratio C/D of the minimum length C of the gap 12 to the arrangement interval D of the ridges 11 and the arrangement interval D of the ridges 11 are the same as those of the ratio C/D and the arrangement interval D of the previous embodiment, respectively.

As shown in fig. 4, one side surface 16a of the pair of side surfaces 16a, 16b may be perpendicular to the surface 5 of the sidewall portion 3 with respect to the ridge 11. Thus, the cross section of the ridge 11 of this embodiment is formed into a right triangle.

In such a ridge 11, the incident angle (not shown) and the reflection angle (not shown) of the light 30 (shown by a two-dot chain line in fig. 4) on the one side surface 16a can be made substantially zero. Thereby, the decorative pattern 7 can effectively reduce reflection from the one side surface 16a toward the outside of the tire 1. On the other hand, on the other side surface 16b not perpendicular to the surface 5, the incident angle θ 1 and the reflection angle θ 2 of the light 30 can be made slightly larger than those of the previous embodiments. This can slightly enhance the reflection of the decorative pattern 7 from the other side surface 16b toward the outside of the tire 1. Therefore, in the decorative pattern 7 of this embodiment, the reflection intensities on the side surfaces 16a and 16b and the surface 5 are different, and the contrast of light can be diversified, so that the appearance of the tire can be improved.

In the decorative pattern 7 of the previous embodiment, the form in which the cross section of the ridge 11 is trapezoidal (shown in fig. 2) and the form in which the ridge is triangular (shown in fig. 4) are illustrated, but the present invention is not limited to this form. The decorative pattern 7 may be formed by combining a trapezoidal shape and a triangular shape in the cross section of the ridge 11, for example. This can further improve the variety of the contrast of light by the decorative pattern 7, and thus can further improve the appearance of the tire 1.

While the particularly preferred embodiments of the present invention have been described in detail, the present invention is not limited to the embodiments shown in the drawings, and can be modified into various embodiments.