Pneumatic tires and tire vulcanization molds

Abstract

The present invention provides a pneumatic tire and a tire vulcanization mold that can reduce the visibility of irregularities on the sidewall surface and improve appearance through a unique visual effect. [Solution] A first reference surface and a plurality of protrusions 40 projecting from the first reference surface are provided in the decorative area of ​​the sidewall surface. The shape of the protrusions 40 has a longitudinal direction LD and a transverse longitudinal direction SD and tapers toward both sides of the longitudinal direction LD. The protrusions 40 have a ridge line 44 extending in the longitudinal direction LD in the region of one longitudinal side LD1, a first slope 41 whose protrusion height decreases toward the one transverse side SD1 from the ridge line 44, a second slope 42 whose protrusion height decreases toward the other transverse side SD2 from the ridge line 44, and a third slope 43 located in the region of the other longitudinal side LD2, whose protrusion height decreases toward the other longitudinal side LD2.

Description

Technical Field

[0001] The present disclosure relates to a pneumatic tire and a tire vulcanizing mold for vulcanizing and molding the pneumatic tire.

Background Art

[0002] Conventionally, pneumatic tires having patterns provided on the sidewall surface are known. In the tire described in Patent Document 1, the pattern is formed by a serration in which a plurality of ridges are arranged. However, the pattern by serration may be poor in the effect of making the unevenness appearing on the sidewall surface during inflation less noticeable. Also, in the tire described in Patent Document 2, the pattern is formed by arranging a large number of protrusions. However, this document focuses on the riding comfort performance and the handling stability performance, and does not suggest a method of producing a specific visual effect by the pattern.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Patent Document 2

Summary of the Invention

Problems to be Solved by the Invention

[0004] The present disclosure has been made in view of the above circumstances, and an object thereof is to provide a pneumatic tire and a tire vulcanizing mold that can make the unevenness appearing on the sidewall surface less noticeable and improve the appearance with a specific visual effect.

Means for Solving the Problems

[0005] The pneumatic tire of this disclosure comprises a sidewall surface including a decorative area. The decorative area is provided with a first reference surface and a plurality of projections protruding from the first reference surface. Viewed from a direction perpendicular to the first reference surface, the shape of the projections has a longitudinal direction and a transversely longitudinal direction and tapers toward both sides in the longitudinal direction. The projections have a ridge line extending longitudinally in a region on one side in the longitudinal direction, a first slope whose projection height decreases toward one side in the transverse direction from the ridge line, a second slope whose projection height decreases toward the other side in the transverse direction from the ridge line, and a third slope line located in the region on the other side in the longitudinal direction and whose projection height decreases toward the other side in the longitudinal direction.

[0006] The tire vulcanizing die of this disclosure includes a sidewall molding surface for molding a sidewall surface including a decorative region. The decorative molding region corresponding to the decorative region is provided with a first mold reference surface and a plurality of depressions recessed from the first mold reference surface. Viewed from a direction perpendicular to the first mold reference surface, the shape of the depressions has a longitudinal direction and a transverse longitudinal direction and tapers toward both sides in the longitudinal direction. The depressions have a mold ridge extending in the longitudinal direction in a region on one side in the longitudinal direction, a first mold slope whose depression depth decreases toward one side in the transverse direction from the mold ridge, a second mold slope whose depression depth decreases toward the other side in the transverse direction from the mold ridge, and a third mold slope located in a region on the other side in the longitudinal direction, whose depression depth decreases toward the other side in the longitudinal direction. [Brief explanation of the drawing]

[0007] [Figure 1] A schematic cross-sectional view of a key part of an example of a pneumatic tire. [Figure 2] Side view showing the sidewall section as seen from the axial side of the tire. [Figure 3] Cross-sectional view of the pattern along the circumferential direction of the tire. [Figure 4] Plan view showing part of the pattern [Figure 5] Plan view of the protrusion [Figure 6](A) Side view, (B) Cross-sectional view taken along arrow AA, and (C) Cross-sectional view taken along arrow BB of the projection [Figure 7] Perspective view of the protrusion [Figure 8] (A) Side view and (B) Perspective view of the projection in the modified example [Figure 9] Cross-sectional view showing an example of a tire vulcanization mold. [Figure 10] Cross-sectional view of the part of the decorative molding area corresponding to the pattern, along the tire circumference. [Figure 11] Plan view of the recess [Figure 12] (A) Side view section of the depression, (B) section viewed from arrow CC, and (C) section viewed from arrow DD. [Modes for carrying out the invention]

[0008] Embodiments of this disclosure will be described with reference to the drawings.

[0009] Figure 1 is a schematic cross-sectional view of the main parts of the pneumatic tire T of this embodiment. The pneumatic tire T is an automobile tire comprising a pair of bead portions 1, a pair of sidewall portions 2 extending radially outward from each of the bead portions 1, and a tread portion 3 connected to the radially outward ends of each of the sidewall portions 2. An annular bead core 1a is embedded in the bead portion 1. The bead core 1a is formed by covering a converging body such as steel wire with rubber. A bead filler 1b is arranged on the radially outward side of the bead core 1a. The bead filler 1b is formed of triangular-shaped rubber extending radially outward from the bead core 1a.

[0010] Here, the circumferential direction of the tire is the direction around the central axis CA of the tire T (see Figure 2). The radial direction of the tire is the direction along the diameter of the tire T. The side approaching the central axis CA is the inner side in the radial direction of the tire, and the side moving away from the central axis CA is the outer side in the radial direction of the tire. The axial direction of the tire is the direction parallel to the central axis CA. The side approaching the tire equator (not shown) is the inner side in the axial direction of the tire, and the side moving away from the tire equator is the outer side in the axial direction of the tire. The tire equator is a virtual line located in the center of the tire T in the axial direction and perpendicular to the central axis CA when the tire T is viewed from the outside in the radial direction of the tire.

[0011] Unless otherwise specified, the dimensions and angles of each part of the tire are determined in an unloaded state, mounted on a standard rim and filled with the standard internal pressure. The standard rim is the rim specified for each tire by each standard in the standard system on which the tire is based; for example, it is the standard rim for JATMA, and the "Measuring Rim" for TRA and ETRTO. The standard internal pressure is the air pressure specified for each tire by each standard in the standard system on which the tire is based; for truck and bus tires and light truck tires, it is the maximum air pressure for JATMA, the value corresponding to the Load Index listed in the table "TIRE LOAD LIMITS AT VARIOUS COLD INFLATION PRESSURES" for TRA, and the "INFLATION PRESSURE" for ETRTO. For passenger car tires, it is usually 180kPa, but for tires marked Extra Load or Reinforced, it is 220kPa.

[0012] The tire T includes a carcass 4 extending in a toroidal shape across between a pair of bead portions 1. The carcass 4 is wound up from the inner side to the outer side in the tire axial direction so as to sandwich the bead core 1a and the bead filler 1b. The carcass 4 is formed by a carcass ply formed by rubber-coating a carcass cord. The carcass cords are aligned in a direction intersecting the tire circumferential direction (for example, a direction forming an angle of 75 to 90 degrees with respect to the tire circumferential direction). As the material of the carcass cord, a metal such as steel or an organic fiber such as polyester, rayon, nylon, or aramid is preferably used.

[0013] The tire T includes a belt 5 laminated on the outer side in the tire radial direction of the carcass 4. The belt 5 is formed by a plurality (two in this embodiment) of belt plies laminated on each other. Each belt ply is formed by rubber-coating a belt cord. The belt cords are aligned in a direction inclined with respect to the tire circumferential direction (for example, a direction forming an angle of 20 to 30 degrees with respect to the tire circumferential direction). As the material of the belt cord, a metal such as steel is preferably used. The plurality of belt plies are laminated such that the belt cords cross each other in opposite directions therebetween.

[0014] Although not adopted in this embodiment, a structure in which a belt reinforcing material is laminated on the outer side in the tire radial direction of the belt 5 may be used. The belt reinforcing material is formed by a belt reinforcing ply formed by rubber-coating a belt reinforcing cord. The belt reinforcing cords are aligned substantially parallel to the tire circumferential direction. The belt reinforcing ply is formed, for example, by spirally winding one or a plurality of rubber-coated belt reinforcing cords along the tire circumferential direction. As the material of the belt reinforcing cord, the above-described organic fiber is preferably used. The belt reinforcing material may be in a form that entirely covers the belt 5 or may be in a form that partially covers the belt 5 (for example, only both ends).

[0015] On the inner surface of the tire T, an inner liner rubber 6 made of a rubber excellent in air barrier properties such as butyl rubber is provided. On the outer side in the tire axial direction of the bead core 1a and the bead filler 1b, a rim strip rubber 7 forming the outer surface of the bead portion 1 is provided. On the outer side in the tire axial direction of the carcass 4, a sidewall rubber 8 forming the outer surface of the sidewall portion 2 is provided. On the outer side in the tire radial direction of the belt 5, a tread rubber 9 forming the outer surface of the tread portion 3 is provided. The tread rubber 9 has a tread pattern formed according to required tire performance and usage conditions.

[0016] FIG. 2 is a side view showing the sidewall portion 2 as viewed from the outer side in the tire axial direction. As shown in FIG. 2, the pneumatic tire T includes a sidewall surface 20 including a decorative region 10. The decorative region 10 has an annular shape centered on the central axis CA. The decorative region 10 is provided as a band-shaped region having a certain width sandwiched between an inner diameter side line 11 with a relatively small diameter and an outer diameter side line 12 with a relatively large diameter. The inner diameter side line 11 and the outer diameter side line 12 may each be a line visually recognized as a convex portion, a concave portion or a step on the tire surface, or may be a virtual line. Such a sidewall surface 20 is formed on the outer surface of at least one of the pair of sidewall portions 2.

[0017] The decorative region 10 may be a region including the tire maximum width position 2M (see FIG. 1), or may be a region on the outer side in the tire radial direction from the tire maximum width position 2M. The tire maximum width position 2M is the position where the sidewall surface 20 is farthest from the tire equator line in the tire axial direction. The outer diameter side line 12 is preferably located on the outer side in the tire radial direction from the tire maximum width position 2M and on the inner side in the tire radial direction of the mold cut position Ps or more thereof. The mold cut position Ps is a position corresponding to the boundary (split position) between the tread mold portion Mt (see FIG. 9) for molding the tread portion 3 and the side mold portion Ms (see FIG. 9) for molding the sidewall portion 2, and may be identified from the parting line appearing on the sidewall portion 2.

[0018] The decorative area 10 is provided with a mark 13 and a pattern 14. The mark 13 is arranged at multiple locations (two locations in this embodiment) in the circumferential direction of the tire, and the pattern 14 is arranged between them. The mark 13 is composed of letters (including numbers) and symbols, and may include various display information such as tire size, manufacturer name, product name, and brand. The mark 13 can be formed by a bulge protruding outward in the axial direction of the tire, or a depression recessed inward in the axial direction of the tire. The pattern 14 is provided on the first reference surface 31, which will be described later, and exhibits a predetermined figure. The shape of the figure is not particularly limited.

[0019] Figure 3 is a cross-sectional view of the pattern 14 along the circumferential direction of the tire. The decorative area 10 is provided with a first reference surface 31 and a plurality of protrusions 40 projecting from the first reference surface 31. In this embodiment, the first reference surface 31 is recessed relative to the surrounding second reference surface 32. The second reference surface 32 may be a profile surface on the sidewall surface 20. The profile surface is a smooth curved surface that constitutes the basic contour of the sidewall portion 2. The contour 14c of the pattern 14 is formed by the step difference between the first reference surface 31 and the second reference surface 32. From the viewpoint of ensuring the projection height H40 of the protrusions 40 relative to the first reference surface 31 (see Figure 6), the recess depth D31 of the first reference surface 31 relative to the second reference surface 32 is preferably 0.1 mm or more, and more preferably 0.2 mm or more. Ensuring the projection height H40 is beneficial in enhancing the visual effect described later.

[0020] Figure 4 is a plan view showing a part of the pattern 14. The pattern 14 is composed of multiple protrusions 40 arranged repeatedly in the circumferential and radial directions of the tire. At the edge (start point) of the pattern 14, the protrusions 40 are cut off along the contour 14c. The location where the protrusions 40 are cut off can be set arbitrarily and may differ for each pattern 14. Alternatively, the contour 14c may extend between adjacent protrusions 40 so that the protrusions 40 are not cut off midway.

[0021] Figure 5 is a plan view of the projection 40. Note that, with respect to the projection 40 and the pattern 14, the plan view (or plan view) refers to a view (or perspective) from a direction perpendicular to the first reference plane 31. Figure 6 is (A) a side view, (B) a cross-sectional view taken along arrow AA, and (C) a cross-sectional view taken along arrow BB of the projection 40. Figure 7 is a perspective view of the projection 40.

[0022] Viewed from a direction perpendicular to the first reference plane 31, the shape of the projection 40 has a longitudinal direction LD and a transverse longitudinal direction SD, and tapers toward both sides of the longitudinal direction LD. The projection 40 has a ridge line 44, a first slope 41, a second slope 42, and a third slope 43. The ridge line 44 extends in the longitudinal direction LD in the region of one longitudinal side LD1. The first slope 41 decreases in projection height toward one transverse side SD1 from the ridge line 44. The second slope 42 decreases in projection height toward the other transverse side SD2 from the ridge line 44. The third slope 43 is located in the region of the other longitudinal side LD2 and decreases in projection height toward the other longitudinal side LD2.

[0023] With this configuration, the irregularities that appear on the sidewall surface 20 when inflated, especially the streaky irregularities extending in the tire diameter direction, can be made less noticeable compared to serrations, which are an arrangement of ridges. Also, when light hits the protrusion 40, it is reflected by multiple slopes, making the pattern 14 of the decorative area 10 appear three-dimensional. In this case, in the region LD1 on one longitudinal side of the protrusion 40, the first slope 41 and the second slope 42 are oriented in opposite directions with respect to the short direction SD, so when viewed from the short direction SD, one appears brighter and the other darker. Moreover, in the region LD2 on the other longitudinal side of the protrusion 40, the third slope 43 facing the longitudinal direction LD reflects light differently from the first slope 41 and the second slope 42. As a result, the pattern 14 appears to sparkle like a water surface due to the reflection of light, improving the appearance through a unique visual effect.

[0024] The projection 40 has a length L40 in the longitudinal direction and a width W40 in the short direction SD. The length L40 is set to, for example, 2.0 to 4.0 times the width W40. The width W40 is preferably 0.5 mm or more, and more preferably 2.0 mm or more. The width W40 is, for example, 3.0 mm or less. In this embodiment, a pattern 14 is formed by arranging a plurality of projections 40 with the same length L40 and width W40 (see Figure 4). The length L40 and width W40 may be different for each pattern 14, in which case the appearance when light is reflected will change for each pattern 14, thus changing the visual effect. It is preferable that there are two or three combinations of length L40 and width W40 applied to a single decorative area 10.

[0025] The ridge line 44 has an end 44a on one longitudinal side LD1 and an end 44b on the other longitudinal side LD2. End 44a is substantially located on the first reference plane 31. End 44b is located away from the first reference plane 31, and the projection height gradually decreases from end 44b toward end 44a. End 44b is located in the region of the longitudinal side LD1 with reference to the center of the longitudinal LD ​​of the projection 40. In this embodiment, end 44b is set to a position that overlaps with the top portion 40t, which will be described later, in a plan view. The length L44 of the ridge line 44 in a plan view is set to, for example, 20% or more and less than 45% of the length L40. The cross-sectional shape of the ridge line 44 shown in Figure 6(B) is pointed in a V shape, but it may also be a curved shape via an arc with a radius of curvature of 0.5 mm or less, for example.

[0026] The first bevel 41 and the second bevel 42 may each be formed by planes extending to the first reference plane 31. In plan view, the first bevel 41 has a shape that tapers towards both sides in the longitudinal direction LD. The first bevel 41 is formed in a triangular shape in plan view. The second bevel 42 is formed to be symmetric to the first bevel 41 with respect to the edge line 44. In this embodiment, the opening angle θ between the first bevel 41 and the second bevel 42 is obtuse (i.e., 90 degrees < θ < 180 degrees). With this configuration, advantageous effects are achieved such as reduced snagging when removing tires from the tire vulcanization mold and reduced contamination by promoting the entry of particles (plastic beads, glass beads, dry ice, etc.) during mold cleaning.

[0027] The third inclined surface 43 is located on the other longitudinal side LD2 of the first inclined surface 41 and the second inclined surface 42. The third inclined surface 43 may be formed by a plane extending toward the first reference plane 31. The third inclined surface 43 has a plan view shape that tapers toward both sides in the longitudinal direction LD. The portion of the third inclined surface 43 that tapers toward one longitudinal side LD1 is located between the first inclined surface 41 and the second inclined surface 42 in the short direction SD. The projection 40 has its apex 40t, which is the part furthest from the first reference plane 31, in the region of one longitudinal side LD1, and the third inclined surface 43 extends from the apex 40t toward the other longitudinal side LD2. With respect to the first reference plane 31, the apex 40t is at a higher position than the end 44b, but these height positions may be the same.

[0028] The boundary 45 between the first slope 41 and the third slope 43 extends from end 44b inclined toward the other longitudinal side LD2 toward the other short-side SD1. The boundary 46 between the second slope 42 and the third slope 43 extends from end 44b inclined toward the other short-side SD2 toward the other longitudinal side LD2. The boundaries 45 and 46 extend in a straight line in plan view and, together with the ridge line 44, form a Y shape. The boundaries 45 and 46 may also extend in a curved shape in plan view. In this embodiment, the boundaries 45 and 46 are formed in a stepped shape, and with this configuration, it is possible to set a new surface (a stepped surface along the boundaries 45 and 46) with a different angle from the first to third slopes 41 to 43 while maintaining their sizes, thereby changing the visual effect. However, this is not limited to this, and the boundaries 45 and 46 may be formed by ridge lines.

[0029] Viewed from a direction perpendicular to the first reference plane 31, the third inclined surface 43 is larger than the first inclined surface 41 and the second inclined surface 42. That is, in a plan view, the third inclined surface 43 has a larger area than the first inclined surface 41 and a larger area than the second inclined surface 42. This makes it easier to make the third inclined surface 43 reflect light differently from the first inclined surface 41 and the second inclined surface 42, which is advantageous for improving the appearance through the aforementioned visual effect. In a plan view, the tip of the other longitudinal side LD2 of the third inclined surface 43 is pointed in a V-shape, but it may also be a rounded shape as shown by the dashed line in Figure 5.

[0030] As shown in Figure 5, the projection 40 is formed in a rhombic shape in plan view. In this embodiment, the plan view shape of the projection 40 is substantially composed of three surfaces (first to third bevels 41 to 43). This makes it easy to ensure the size of each bevel, which is advantageous for appropriately achieving the visual effect described above. Furthermore, because the projection 40 has such a simple shape, it is easier for particles to penetrate during mold cleaning compared to cases where it has a relatively complex shape, which is advantageous for suppressing mold contamination. The surface roughness of the first to third bevels 41 to 43 may be substantially the same as each other, or they may differ for each surface.

[0031] The protrusion 40 has a protruding height H40 from the first reference surface 31 to the top 40t. The ratio (W40 / H40) of the width W40 to the protruding height H40 is, for example, 1.0 to 10.0. In the present embodiment, the protruding height H40 of the protrusion 40 is greater than the depression depth D31 of the first reference surface 31 (i.e., D31 < H40). According to such a configuration, a protector effect of protecting the sidewall surface 20 from a curb or the like can be achieved, and the impact resistance can be improved. Further, compared with the case where the protruding height H40 is the same as or smaller than the depression depth D31, the protruding height H40 can be increased, which is convenient for improving the appearance due to the above-described visual effect. The protruding amount P40 of the protrusion 40 with respect to the second reference surface 32 (see FIG. 3) is preferably 0.1 mm or more. The protruding amount P40 is preferably smaller than the depression depth D31.

[0032] As shown in FIG. 4, in the present embodiment, a gap 50 is provided between the adjacent protrusions 40. The plurality of protrusions 40 are arranged in a manner that they do not contact each other while providing an interval corresponding to the gap 50. According to such a configuration, in addition to the first to third inclined surfaces 41 to 43, the first reference surface 31 exposed by the gap 50 also becomes a light reflecting surface, and an effect that the pattern 14 can be seen shining brightly can be obtained well. From the viewpoint of appropriately achieving such an effect, the size of the gap 50 (the interval between the protrusions 40) is set to, for example, 0.1 mm or more. Further, from the viewpoint of appropriately ensuring the arrangement density of the protrusions 40, the size of the gap 50 is set to, for example, 1.0 mm or less. The size of the gap 50 may be substantially zero, and the adjacent protrusions 40 may be arranged while being in contact with each other.

[0033] In the example shown in Figure 4, multiple rows of protrusions 40A are formed, with the protrusions 40 arranged in the short direction SD. The phase of each row of protrusions 40A is half a phase shift in the longitudinal direction LD and the short direction SD relative to the phase of other adjacent rows of protrusions 40A. This allows for the arrangement of protrusions 40 that taper toward both sides of the longitudinal direction LD, which is advantageous for improving appearance through the aforementioned visual effect. In this embodiment, the longitudinal direction LD of the protrusions 40 is along the tire diameter direction, for example, a direction where the angle with respect to the tire diameter direction is less than 45 degrees. However, it is not limited to this, and the longitudinal direction LD may be in other directions, for example, along the tire circumferential direction.

[0034] In the modified version of the projection 40 shown in Figure 8, the boundaries 45 and 46 have a rounded shape. Boundaries 45 and 46 each have an arc-shaped curved surface that is convex in the direction away from the first reference surface 31. A curved surface of a similar shape is also set between the third inclined surface 43 and the first reference surface 31 in the region of LD2 on the other longitudinal side of the projection 40. With this configuration, advantageous effects can be obtained, such as reducing snagging when removing the tire from the tire vulcanization mold and promoting the entry of particles during mold cleaning, thereby suppressing contamination.

[0035] Figure 9 is a cross-sectional view of a tire vulcanization mold M used for vulcanizing a pneumatic tire T. In Figure 9, the tire T is shown by a dashed line, and the tire T is set in the mold M with its axial direction facing up and down. The mold M comprises a pair of bead rings Mb into which the bead portion 1 of the tire T is fitted, a pair of side mold portions Ms that contact the sidewall portion 2 of the tire T, and a tread mold portion Mt that contacts the tread portion 3 of the tire T. The mold M also includes a sidewall molding surface Mf for molding the sidewall surface 20 including the decorative area 10. The sidewall molding surface Mf is provided on the inner surface of the side mold portion Ms.

[0036] Figure 10 is a cross-sectional view of the decorative molding region corresponding to the decorative region 10, and more specifically, a cross-sectional view along the tire circumferential direction of the portion of the decorative molding region corresponding to the pattern 14. Figure 10 is equivalent to an inverted version of Figure 3. The decorative molding region is provided with a first mold reference surface 61 and a plurality of depressions 70 that are recessed from the first mold reference surface 61. The first mold reference surface 61 is raised relative to the second mold reference surface 62 surrounding it. The depth of the depressions 70 is greater than the height of the raised first mold reference surface 61 relative to the second mold reference surface 62.

[0037] Figure 11 is a plan view of the recess 70. Figure 12 is a (A) side cross-sectional view, (B) cross-sectional view taken along arrow CC, and (C) cross-sectional view taken along arrow DD of the recess 70. Figure 12 corresponds to an inverted version of Figure 6. When viewed from a direction perpendicular to the first mold reference surface 61, the shape of the recess 70 has a longitudinal direction LD and a transverse longitudinal direction SD, and tapers toward both sides of the longitudinal direction LD. The recess 70 has a mold ridge 74 extending in the longitudinal direction LD in the region of one longitudinal side LD1, a first mold slope 71 whose recess depth decreases toward one transverse side SD1 from the mold ridge 74, a second mold slope 72 whose recess depth decreases toward the other transverse side SD2 from the mold ridge 74, and a third mold slope 73 located in the region of the other longitudinal side LD2, whose recess depth decreases toward the other longitudinal side LD2.

[0038] The first mold reference surface 61, the second mold reference surface 62, and the recess 70 have configurations corresponding to the first reference surface 31, the second reference surface 32, and the projection 40, respectively. Furthermore, the mold ridge line 74, the first mold slope 71, the second mold slope 72, and the third mold slope 73 of the recess 70 have configurations corresponding to the ridge line 44, the first slope 41, the second slope 42, and the third slope 43 of the projection 40, respectively. With such a mold M, the above-described pneumatic tire T is obtained, in which the decorative area 10 of the sidewall surface 20 is provided with the first reference surface 31 and a plurality of projections 40 protruding from the first reference surface 31. The configuration of the tire T has already been explained with reference to Figures 1 to 8, and it is possible to make the irregularities appearing on the sidewall surface 20 less noticeable and improve the appearance with a unique visual effect. For details on other configurations of the recess 70, preferred dimensions, shape, arrangement, and variations, refer to the previously described description of the projection 40.

[0039] Those skilled in the art will understand that the embodiments described above are specific examples of the following embodiments.

[0040] [1] The pneumatic tire of this disclosure has a sidewall surface including a decorative area. The decorative area is provided with a first reference surface and a plurality of protrusions projecting from the first reference surface. When viewed from a direction perpendicular to the first reference surface, the shape of the protrusions has a longitudinal direction and a transversely short direction and tapers toward both sides in the longitudinal direction. The protrusions have a ridge line extending in the longitudinal direction in a region on one side in the longitudinal direction, a first slope whose protrusion height decreases toward one side in the short direction from the ridge line, a second slope whose protrusion height decreases toward the other side in the short direction from the ridge line, and a third slope line located in the region on the other side in the longitudinal direction, whose protrusion height decreases toward the other side in the longitudinal direction. With this configuration, the irregularities appearing on the sidewall surface can be made less noticeable, and the appearance can be improved by a unique visual effect.

[0041] [2] In the pneumatic tire described in [1] above, the first and second inclined surfaces may each be formed by planes extending to the first reference plane. With this configuration, the contrast between light and dark on the first and second inclined surfaces when the protrusion is viewed from the short side is increased, resulting in a more three-dimensional appearance of light.

[0042] [3] In the pneumatic tire described in [1] or [2] above, the angle of opening between the first and second inclined surfaces may be obtuse. Such a configuration is useful for reducing snagging during tire demolding and for suppressing mold contamination.

[0043] [4] In any one of the pneumatic tires described in [1] to [3] above, the projection may have a top portion that is furthest from the first reference plane in the region on one side in the longitudinal direction, and the third slope may extend from the top portion toward the other side in the longitudinal direction. This makes it easier to make the third slope shine differently from the first and second slopes, which is advantageous for improving appearance.

[0044] [5] In any one of the pneumatic tires described in [1] to [4] above, the third slope may be larger than the first and second slopes when viewed from a direction perpendicular to the first reference plane. This makes it easier to make the third slope shine differently from the first and second slopes, which is advantageous for improving appearance.

[0045] [6] In any one of the above [1] to [5] pneumatic tires, a plurality of rows of protrusions are formed in which the protrusions are arranged in the short direction, and the phase of the row of protrusions is shifted by half a phase in the longitudinal and short directions of the protrusions with respect to the phase of other adjacent rows of protrusions. With such a configuration, the protrusions can be arranged closely together, which is convenient for improving appearance.

[0046] [7] In any one of the above [1] to [6] pneumatic tires, a gap may be provided between adjacent protrusions. With this configuration, in addition to the first to third slopes, a light-reflecting surface is also set in the gap, so a good sparkling effect can be obtained.

[0047] [8] In any one of the pneumatic tires described in [1] to [7] above, the first reference surface may be recessed relative to the surrounding second reference surface, and the protruding height of the projection may be greater than the recess depth of the first reference surface. With such a configuration, a protective effect can be achieved to protect the sidewall surface from curbs and the like, thereby improving resistance to damage.

[0048] [9] The tire vulcanization mold of this disclosure includes a sidewall molding surface for molding a sidewall surface including a decorative area. The decorative molding area corresponding to the decorative area is provided with a first mold reference surface and a plurality of depressions recessed from the first mold reference surface. When viewed from a direction perpendicular to the first mold reference surface, the shape of the depressions has a longitudinal direction and a transverse longitudinal direction and tapers toward both sides in the longitudinal direction. The depressions have a mold ridge extending in the longitudinal direction in a region on one side in the longitudinal direction, a first mold slope whose depression depth decreases toward one side in the transverse direction from the mold ridge, a second mold slope whose depression depth decreases toward the other side in the transverse direction from the mold ridge, and a third mold slope located in the region on the other side in the longitudinal direction, whose depression depth decreases toward the other side in the longitudinal direction. With this configuration, the irregularities that appear on the sidewall surface of the vulcanized tire can be made less noticeable, and the appearance can be improved by a unique visual effect.

[0049] The pneumatic tire of this disclosure can be constructed in the same way as a normal pneumatic tire, except for the sidewall surface being configured as described above, and any conventionally known materials, shapes, structures, and manufacturing methods can be used.

[0050] The tire vulcanizing mold of this disclosure can be configured in the same way as a conventional tire vulcanizing mold, except that the sidewall molding surface for forming the sidewall surface is configured as described above, and any conventionally known materials, shapes, structures, and mechanisms can be used.

[0051] This disclosure is not limited in any way to the embodiments described above, and various improvements and modifications are possible without departing from its essence. Furthermore, the configurations adopted in the embodiments described above can be adopted in any combination. [Explanation of Symbols]

[0052] 10 Decorative area, 20 Sidewall surface, 31 First reference surface, 40 Projection, 40A Row of projections, 40t Top, 41 First slope, 42 Second slope, 43 Third slope, 44 Ridge, 50 Gap, 61 First mold reference surface, 70 Recess, 71 First mold slope, 72 Second mold slope, 73 Third mold slope, 74 Mold ridge, LD Longitudinal direction, LD1 One side of the longitudinal direction, LD2 The other side of the longitudinal direction, SD Short direction, SD1 One side of the short direction, SD2 The other side of the short direction, T Pneumatic tire

Claims

1. It has a side wall surface that includes a decorative area, The decorative region is provided with a first reference surface and a plurality of protrusions projecting from the first reference surface. When viewed from a direction perpendicular to the first reference plane, the shape of the projection has a longitudinal direction and a transversely longitudinal direction, and tapers toward both sides in the longitudinal direction. The aforementioned protrusion is A ridge extending in the longitudinal direction in a region on one side in the longitudinal direction, A first slope whose protruding height decreases toward one side in the shorter direction from the aforementioned ridge, A second slope whose protruding height decreases toward the other side in the shorter direction from the aforementioned ridge, A pneumatic tire having a third slope positioned in the region on the other side in the longitudinal direction, with its protruding height decreasing toward the other side in the longitudinal direction.

2. The pneumatic tire according to claim 1, wherein the first slope and the second slope are each formed by planes extending to the first reference plane.

3. The pneumatic tire according to claim 1, wherein the angle of opening between the first slope and the second slope is obtuse.

4. The pneumatic tire according to claim 1, wherein the projection has a top portion that is furthest from the first reference plane in a region on one side in the longitudinal direction, and the third slope extends from the top portion toward the other side in the longitudinal direction.

5. The pneumatic tire according to claim 1, wherein, when viewed from a direction perpendicular to the first reference plane, the third slope is larger than the first and second slopes.

6. Multiple rows of protrusions are formed, with the aforementioned protrusions arranged in the short direction. The pneumatic tire according to claim 1, wherein the phase of the row of protrusions is shifted by half a phase in the longitudinal and transverse directions of the protrusions with respect to the phase of other rows of protrusions adjacent to it.

7. The pneumatic tire according to claim 1, wherein a gap is provided between the adjacent protrusions.

8. The pneumatic tire according to any one of claims 1 to 7, wherein the first reference surface is recessed relative to the surrounding second reference surface, and the protruding height of the projection is greater than the recess depth of the first reference surface.

9. It has a sidewall molding surface for shaping the sidewall surface including the decorative area, The decorative molding region corresponding to the aforementioned decorative region is provided with a first mold reference surface and a plurality of depressions recessed from the first mold reference surface. When viewed from a direction perpendicular to the first mold reference surface, the shape of the recess has a longitudinal direction and a transversely longitudinal direction, and tapers toward both sides in the longitudinal direction. The aforementioned depression is, In the region on one side in the longitudinal direction, the mold ridge extends in the longitudinal direction, A first mold slope, in which the depth of depression is reduced toward one side in the shorter direction from the mold ridge, A second mold slope, in which the depth of depression is reduced toward the other side in the shorter direction from the mold ridge, A tire vulcanizing mold having a third mold inclined surface located in the region on the other side in the longitudinal direction, with the depth of depression decreasing toward the other side in the longitudinal direction.

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