pneumatic tires

Abstract

To provide a pneumatic tire generating a new visual effect.SOLUTION: There is provided a pneumatic tire in which a decorative region 11 is provided on a side wall surface 10, three kinds of planes 21, 22 and 23 having different inclinations to a profile surface are laid all over the decorative region 11, the two kinds of planes 21, 22 and 23 among the three kinds of planes 21, 22 and 23 are aligned in a first direction and form a pair, the plurality of kinds of pairs having different combinations are aligned in a second direction, and boundaries of the two planes 21, 22 and 23 aligned in the first direction are deviated in the first direction between the adjacent pairs in the second direction.SELECTED DRAWING: Figure 3

Description

[Technical Field]

[0001] The present invention relates to a pneumatic tire. [Background technology]

[0002] Conventionally, pneumatic tires have been known that have a concave-convex pattern on the sidewall surface. Most of the concave-convex patterns consist of numerous linearly extending ridges arranged at equal intervals. Also known are patterns that consist of numerous identically shaped three-dimensional shapes. For example, the pattern disclosed in Patent Document 1 is made up of numerous quadrangular pyramidal portions, each of which is arranged as a concave surface relative to a reference plane. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Application Laid-Open No. 2008-273505 Summary of the Invention [Problem to be solved by the invention]

[0004] Incidentally, while beautiful patterns are frequently proposed, there have not been many proposals for groundbreaking patterns that produce unprecedented visual effects.

[0005] Therefore, an object of the present invention is to provide a pneumatic tire that produces a new visual effect. [Means for solving the problem]

[0006] The pneumatic tire of the embodiment is characterized in that in a pneumatic tire having a decorative area on the sidewall surface, three types of planes with different inclinations relative to the profile surface are laid out in the decorative area, two of the three types of planes are lined up in a first direction to form pairs, multiple types of pairs with different combinations are lined up in a second direction, and between pairs adjacent in the second direction, the boundaries of the two planes lined up in the first direction are shifted in the first direction. [Effects of the Invention]

[0007] Due to the above-mentioned features, the pneumatic tire of the embodiment produces a new visual effect. [Brief explanation of the drawings]

[0008] [Figure 1] 1 is an axial half cross-sectional view of a pneumatic tire. [Figure 2] A view of the sidewall surface from the axial direction of the tire. [Figure 3] FIG. [Figure 4] A diagram showing one of the assemblies in Figure 3. [Figure 5] Cross-sectional view taken along line DD in Figure 4. [Figure 6] Cross-sectional view taken along line EE in Figure 4. [Figure 7] Cross-sectional view taken along line FF in Figure 4. [Figure 8] Cross section along line GG in Figure 4. [Figure 9] FIG. 4 is a cross-sectional view of a decorative region near an end in the tire radial direction. [Figure 10] 10 is a cross-sectional view of a pair of modified examples. [Figure 11] 10 is a cross-sectional view of a pair of modified examples. [Figure 12] FIG. 10 is a cross-sectional view of a decorative region in the vicinity of a radial end of the tire in a modified example. [Figure 13] FIG. 10 is a cross-sectional view of a decorative region in the vicinity of a radial end of the tire in a modified example. [Figure 14] FIG. 10 is a cross-sectional view of a decorative region in the vicinity of a radial end of the tire in a modified example. DETAILED DESCRIPTION OF THE INVENTION

[0009] Fig. 1 shows the cross-sectional structure of a pneumatic tire 1 according to an embodiment. Note that Fig. 1 shows only half of the tire in the axial direction, and the actual pneumatic tire 1 is substantially symmetrical with respect to a center line C. The tire axial direction is indicated by arrow A in Fig. 1, the tire radial direction is indicated by arrow B in Figs. 1 and 2, and the tire circumferential direction is indicated by arrow R in Fig. 2.

[0010] The pneumatic tire 1 has bead portions 9 on both axial sides of the tire. The bead portions 9 each include a bead core 9a made of a circularly wound steel wire and a rubber bead filler 9b provided radially outward of the bead core 9a.

[0011] One or two carcass plies 2 are laid across the bead portions 9 on both axial sides of the tire. The carcass ply 2 is a sheet-like member in which numerous ply cords arranged in a direction perpendicular to the tire circumferential direction are covered with rubber. The carcass ply 2 forms the skeleton shape of the pneumatic tire 1 between the bead portions 9 on both axial sides of the tire, and wraps around the bead portions 9 by being folded back from the axially inner side to the axially outer side. In addition, a rubber chafer 3 is provided at the axially outer side of the folded back portion 2a of the carcass ply 2.

[0012] Furthermore, a plurality of belts 4 are provided on the radially outer side of the carcass ply 2, and a belt reinforcing layer 5 is provided on the radially outer side of the belts 4. The belt 4 is a member made of a large number of steel cords covered with rubber. The belt reinforcing layer 5 is a member made of a large number of organic fiber cords covered with rubber. A tread rubber 6 is provided on the radially outer side of the belt reinforcing layer 5. The tread rubber 6 has a large number of grooves formed therein to form a tread pattern.

[0013] In addition, sidewall rubber 7 is provided on both axial sides of the carcass ply 2. The tread rubber 6 and the sidewall rubber 7 overlap at the buttresses, but either the tread rubber 6 or the sidewall rubber 7 may overlap on the tire surface side. The radially inner portion of the sidewall rubber 7 extends close to the bead portion 9 and covers part of the rubber chafer 3.

[0014] A rim line 8, a small protrusion about 1 mm high, is formed at the boundary on the tire surface between the sidewall rubber 7 and the rubber chafer 3. The rim line 8 runs around the tire circumferentially. Note that instead of the rim line 8, a rim protector may be provided that protrudes in the same location as the rim line 8 so that its cross section is roughly triangular. The area from the rim line 8 or rim protector to the edge of the tread in the tire radial direction is defined as the sidewall surface 10.

[0015] Here, the tread edge refers to the axial end of the contact surface of the tread rubber 6 with the road when the tire is mounted on a standard rim, the standard internal pressure is applied, and the standard load is applied. Here, the standard rim refers to the rim specified for each tire in the standard system, including the standard 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 refers to the air pressure specified for each tire in the standard system, including the standard on which the tire is based. For truck / bus tires and light truck tires, it is the maximum air pressure for JATMA, the maximum value listed in the "TIRE LOAD LIMITS AT VARIOUS COLD INFLATION PRESSURE" table for TRA, and the "INFLATION PRESSURE" for ETRTO. The standard internal pressure for passenger car tires is usually 180 kPa, but is 220 kPa for tires labeled "Extra Load" or "Reinforced." The normal load is the load specified for each tire in the standard system, including the standard on which the tire is based. For JATMA, it is the "maximum load capacity," for TRA, it is the maximum value listed in the table "TIRE LOAD LIMITS AT VARIOUS COLD INFLATION PRESSURES," and for ETRTO, it is the "LOAD CAPACITY." The normal load for tires for passenger cars is a load equivalent to 88% of the above loads. For racing kart tires, the normal load is 392N.

[0016] In addition, a sheet-like inner liner made of rubber with low air permeability is attached to the inside of the carcass ply 2. In addition to these components, components such as an underbelt pad and a chafer are provided as required for the tire's functionality.

[0017] As shown in Figures 1 and 2, a decorative area 11 is provided on at least one of the sidewall surfaces 10 on both axial sides of the tire. The decorative area 11 is in the shape of a ring centered on the tire rotation axis. The decorative area 11 is a band-like area of ​​a constant width sandwiched between a small-diameter circular inner side line 12 and a large-diameter circular outer side line 13. The inner side line 12 and the outer side line 13 may be lines formed by recesses, protrusions, or steps on the tire surface, or may be imaginary lines that do not actually exist.

[0018] The decorative region 11 occupies a part of the range from the position of the maximum width of the pneumatic tire 1 to the tread edge. Here, the position of the maximum width of the pneumatic tire 1 refers to the position where the axial length from the surface of one axial sidewall surface 10 to the surface of the other axial sidewall surface 10 is the longest when the tire is mounted on a standard rim, the standard internal pressure is applied, and a standard load is applied. The width (length in the tire radial direction) of the decorative region 11 is, for example, 5 mm or more and 50 mm or less.

[0019] The decorative region 11 may also be provided in a manner that includes a location where a step is likely to appear on the surface of the sidewall surface 10. The location where a step is likely to appear on the surface of the sidewall surface 10 is typically a location at the end of a tire constituent member. Typical such locations include a location where the interface between the tread rubber 6 and the sidewall rubber 7 appears on the tire surface, a location in the tire axial direction of the turned-up end of the carcass ply 2 (the end of the turned-up portion 2a of the carcass ply 2), etc.

[0020] As shown in Figure 3, three types of planes 21, 22, and 23 are spread throughout the entire decorative area 11. The three types of planes 21, 22, and 23 differ in whether they are inclined relative to the profile surface of the sidewall surface 10 and in the direction of their inclination. The first plane 21 is a plane parallel to the profile surface. The second plane 22 is a plane inclined so as to be higher on one side in the first direction and lower on the other side in the first direction relative to the profile surface. The third plane 23 is a plane inclined so as to be lower on one side in the first direction and higher on the other side in the first direction relative to the profile surface.

[0021] In this embodiment, the first direction is the tire radial direction, one side in the first direction is the tire radial inner side (B1 side in FIGS. 3 to 9), and the other side in the first direction is the tire radial outer side (B2 side in FIGS. 3 to 9). Note that the second direction, which will be described later, is the tire circumferential direction (R direction in FIGS. 3 and 4).

[0022] Here, the profile surface of the sidewall surface 10 refers to the tire surface when there are no irregularities for decoration, etc. The profile surface is a single curved surface that smoothly connects the areas without irregularities on both sides of the decorative area 11 in the tire radial direction.

[0023] Furthermore, the inclination direction of the planes 21, 22, and 23 relative to the profile surface means, strictly speaking, the inclination direction of the planes 21, 22, and 23 relative to a plane perpendicular to the normal to the profile surface (however, this normal is a normal passing through the center positions of the planes 21, 22, and 23).

[0024] The inclination angle of the second plane 22 and the third plane 23 with respect to the profile plane is preferably 10° or more and 30° or less. Furthermore, the height from the lower side to the higher side of the second plane 22 and the third plane 23 in the direction perpendicular to the profile plane (for reference, this height is indicated by the symbol H in FIG. 9) is preferably 2 mm or more and 4 mm or less.

[0025] The three types of planes 21, 22, 23 are all rectangles of the same shape and size when viewed from a direction perpendicular to the profile surface. In this embodiment, the planes 21, 22, 23 are rectangles that are long in the tire radial direction. The ratio of the short side to the long side of the rectangle is preferably 1:1 to 1:20. A rectangle with the ratio of 1:1 is a square. Furthermore, the area of ​​the planes 21, 22, 23 when viewed from a direction perpendicular to the profile surface is, for example, 3 mm 2 More than 7mm 2 is.

[0026] It is sufficient that the three types of planes 21, 22, and 23 are recognizable as rectangles at a glance, and the lengths and angles of each part do not necessarily numerically strictly satisfy the definition of a rectangle. For example, there may be a slight error between the two opposing sides of a rectangle. The difference in length between the two opposing sides is preferably within 10% of the length of either side. There may also be a slight error in the interior angles relative to 90°.

[0027] All of the planes 21, 22, and 23 are recessed relative to the profile surface. As shown in Fig. 9, the entire decorative area 11 is recessed relative to the profile surface 20. The first plane 21, which is parallel to the profile surface 20, forms the bottom surface of the decorative area 11. The inclined second plane 22 and third plane 23 have their lower sides positioned at the bottom surface of the decorative area 11 and their higher sides positioned higher than the bottom surface of the decorative area 11 and lower than the profile surface 20.

[0028] These three types of flat surfaces 21, 22, 23 form unevenness in the decorative region 11. The areas near the higher sides of the second flat surface 22 and the third flat surface 23 are convex, and the first flat surface 21 is concave.

[0029] There is a pattern to the arrangement of the three types of flat surfaces 21, 22, and 23 in the decorative region 11. First, two of the three types of flat surfaces 21, 22, and 23 are aligned in the tire radial direction, which is the first direction, to form pairs. The two types of flat surfaces 21, 22, and 23 that make up a pair are in contact with each other.

[0030] In this embodiment, there are four types of pairs shown in Fig. 4 to Fig. 8. The four types of pairs are a first pair of the second plane 22 on the outer side B2 in the tire radial direction and the first plane 21 on the inner side B1 in the tire radial direction (see Fig. 4 and Fig. 5), a second pair of the third plane 23 on the outer side B2 in the tire radial direction and the second plane 22 on the inner side B1 in the tire radial direction (see Fig. 4 and Fig. 6), a third pair of the third plane 23 on the outer side B2 in the tire radial direction and the first plane 21 on the inner side B1 in the tire radial direction (see Fig. 4 and Fig. 7), and a fourth pair of the first plane 21 on the outer side B2 in the tire radial direction and the third plane 23 on the inner side B1 in the tire radial direction (see Fig. 4 and Fig. 8).

[0031] As shown in Figures 4, 5 and 8, in the first pair and the fourth pair, a step is formed at the boundary between the two planes 21, 22, 23 that make up the pair. In addition, in the second pair and the third pair, the boundary between the two planes 21, 22, 23 that make up the pair is curved. In the following description, the boundary between the two planes that make up the pair is referred to as the "internal boundary of the pair."

[0032] These four types of pairs are lined up in the tire circumferential direction R, which is the second direction. They are lined up in the order of the first pair to the fourth pair. Adjacent pairs are in contact with each other. A single aggregate is formed by gathering together the four types of pairs. The entire area shown in FIG. 4 is one aggregate. A plurality of aggregates are laid out tightly in the decorative area 11.

[0033] As shown in FIG. 4, the positions of the intra-pair boundaries 24 are shifted in the tire radial direction (directions B1 and B2) between two pairs adjacent in the tire circumferential direction R. The distance of the shift in the tire radial direction is half the length of the planes 21, 22, and 23 in the tire radial direction. Therefore, the intra-pair boundaries 24 in the odd-numbered pairs in the tire circumferential direction R (first pair and third pair) are aligned on one line, and the intra-pair boundaries 24 in the even-numbered pairs in the tire circumferential direction R (second pair and fourth pair) are aligned on another line. The line through which the intra-pair boundaries 24 pass is referred to as the reference line L (see FIG. 4). The reference line L is an imaginary line extending in the tire circumferential direction R.

[0034] Because the intra-pair boundary 24 is shifted in this manner, two planes 21, 22, 23 adjacent in the tire circumferential direction R are shifted in the tire radial direction (directions B1 and B2) by half the length of one plane 21, 22, 23 in the tire radial direction.

[0035] A reference line L passing through the intra-pair boundary 24 of a certain pair passes through the tire radial center positions of the planes 21, 22, and 23 of another pair adjacent in the tire circumferential direction R. On this reference line L, a step is formed between the planes 21, 22, and 23 adjacent in the tire circumferential direction R. For example, as shown in FIG. 5 , the intra-pair boundary 24 of a first pair (which is also the end of the second plane 22) is located higher than the second plane 22 of a second pair adjacent in the tire circumferential direction R. A step is formed between the intra-pair boundary 24 of the first pair and the second plane 22 of the second pair. Similarly, as shown in FIGS. 4 and 6 to 8 , steps are also formed between the planes 21, 22, and 23 adjacent in the tire circumferential direction R between the second pair and the third pair, between the third pair and the fourth pair, and between the fourth pair and the first pair.

[0036] Although not shown, a mark or the like may be provided on the outside of the decorative area 11 on the sidewall surface 10. The mark or the like is depicted by projections and recesses.

[0037] Such decorative region 11 can be formed by a mold during vulcanization molding of the pneumatic tire 1. A plurality of flat surfaces 21, 22, and 23 are formed on the molding surface of the mold used for vulcanization molding.

[0038] As described above, in the pneumatic tire 1 of this embodiment, three types of flat surfaces 21, 22, 23 with different inclinations relative to the profile surface are laid out in the decorative region 11. Two of the types of flat surfaces 21, 22, 23 are aligned in the tire radial direction to form pairs, and multiple types of pairs with different combinations are aligned in the tire circumferential direction R. Furthermore, between pairs adjacent in the tire circumferential direction R, the intra-pair boundary 24 (the boundary between the two flat surfaces 21, 22, 23 aligned in the tire radial direction) is offset in the tire radial direction. This creates a new visual effect from the pneumatic tire 1.

[0039] Specifically, the three types of flat surfaces 21, 22, and 23 have different inclinations, and therefore reflect light in different directions. Furthermore, because two types of flat surfaces 21, 22, and 23 form pairs, multiple types of pairs with different combinations are lined up in the tire circumferential direction R, and the intra-pair boundaries 24 between two pairs adjacent in the tire circumferential direction R are shifted in the tire radial direction, light is reflected in various directions from the many flat surfaces 21, 22, and 23 within a predetermined range. As a result, a complex shine like that of a water surface (which also reflects light in multiple directions) appears from the decorative area 11, creating a new visual effect.

[0040] Furthermore, the planar surfaces 21, 22, and 23 create unevenness in the decorative area 11, making the decorative area 11 appear three-dimensional. The three-dimensional appearance of the decorative area 11 improves the visibility of the decorative area 11.

[0041] It is also known that, in general, linear depressions extending in the tire radial direction occur on the sidewall surface when the pneumatic tire 1 is inflated (i.e., when internal pressure is applied to the pneumatic tire 1). However, since the sidewall surface 10 of this embodiment has unevenness formed from three types of flat surfaces 21, 22, and 23, such linear depressions are less noticeable.

[0042] Here, since the two types of planes 21, 22, 23 are arranged in the tire radial direction to form pairs, the contrast between light and dark on each plane 21, 22, 23 becomes clear when the pneumatic tire 1 is viewed obliquely from above, and a more complex glow is produced from the decorative area 11.

[0043] Furthermore, on the reference line L that passes through the intra-pair boundary 24 and extends in the tire circumferential direction R, a step is formed between the flat surfaces 21, 22, and 23 that are adjacent in the tire circumferential direction R, which causes light to be reflected differently from the flat surfaces 21, 22, and 23 that are adjacent in the tire circumferential direction R. Also, light is not easily reflected by the step. For these reasons, complex light reflection occurs in the regions of multiple pairs aligned in the tire circumferential direction R, creating a unique aesthetic impression.

[0044] In addition, in the first pair and the fourth pair, a step is formed at the boundary between the two planes that make up the pair (two planes aligned in the tire radial direction), and light is not easily reflected by the step. Therefore, in the decorative area 11 including the first pair and the fourth pair, complex light reflection occurs, creating a unique aesthetic impression.

[0045] Furthermore, because each of the flat surfaces 21, 22, and 23 is a rectangle that is long in the tire radial direction, the decorative region 11 appears brighter when the pneumatic tire 1 is viewed obliquely from above. Furthermore, because the flat surfaces 21, 22, and 23 are aligned in the tire radial direction along the curved profile surface and are rectangles that are long in the tire radial direction, streak-like depressions that occur during inflation and extend in the tire radial direction are less noticeable.

[0046] Furthermore, the decorative region 11 is a band-like region that goes around the tire circumferential direction R, and the flat surfaces 21, 22, 23 are laid out in this band-like region, so that the entire sidewall surface 10 in the circumferential direction is aesthetically pleasing.

[0047] Furthermore, since the entire decorative region 11 is recessed from the profile surface of the sidewall surface 10, the flat surfaces 21, 22, 23 are less likely to hit a curb or the like and be damaged.

[0048] The above-described embodiments are merely examples, and the scope of the invention is not limited to the above-described embodiments. Various modifications can be made to the above-described embodiments without departing from the spirit of the invention. Several modified examples will be described below, but any one of the modified examples may be applied to the above-described embodiments, or two or more of the modified examples may be combined and applied within a range that does not cause contradictions.

[0049] <Change example 1> The decorative area may be an area of ​​a predetermined shape other than a ring. Examples of predetermined shapes include a mark, a stylized character shape, a graphic, etc. As in the above embodiment, a plurality of planes 21, 22, 23 are laid out in each of such predetermined-shape areas. This makes the mark or the like look beautiful.

[0050] <Change example 2> Pairs other than the first to fourth pairs of the above embodiment are also possible. Specifically, a pair of a first plane 21 on the outer side B2 in the tire radial direction and a second plane 22 on the inner side B1 in the tire radial direction (FIG. 10) and a pair of a second plane 22 on the outer side B2 in the tire radial direction and a third plane 23 on the inner side B1 in the tire radial direction (FIG. 11) are also possible.

[0051] <Change example 3> The number of pairs included in one decorative region is not limited to four as in the above embodiment. There may be multiple types of pairs, and pairs of different types may be adjacent to each other in the second direction (for example, the tire circumferential direction). For example, only two types of pairs may be present among the first pair to the fourth pair in the above embodiment.

[0052] <Change Example 4> Contrary to the above embodiment, the first direction may be the tire circumferential direction and the second direction may be the tire radial direction. In this case, two types of planes with different inclinations are aligned in the tire circumferential direction (the first direction) to form a pair, and such pairs are aligned in the tire radial direction (the second direction). Then, between pairs adjacent in the tire radial direction, the intra-pair boundary (the boundary between two planes aligned in the tire circumferential direction) is shifted in the tire circumferential direction. In this modified example, too, it is preferable that each plane be a rectangle whose length is long in the tire radial direction.

[0053] <Change Example 5> Each plane may be a rectangle that is long in the tire circumferential direction.

[0054] <Change Example 6> The height of each plane from the profile surface is not limited. As shown in Fig. 12, the lower sides of the second plane 22 and the third plane 23 may be located lower than the profile surface 20, and the higher sides may be located higher than the profile surface 20. In this case, the convex parts of the unevenness formed by the planes 21, 22, and 23 protrude higher than the profile surface 20, making them more susceptible to light, while the concave parts are recessed below the profile surface 20, making them less susceptible to light. This results in a strong contrast between light and dark.

[0055] 13, the first plane 21 may be at the same height as the profile plane 20. Alternatively, as shown in FIG. [Explanation of symbols]

[0056] 1...pneumatic tire, 2...carcass ply, 2a...turned-up portion, 3...rubber chafer, 4...belt, 5...belt reinforcing layer, 6...tread rubber, 7...sidewall rubber, 8...rim line, 9...bead portion, 9a...bead core, 9b...bead filler, 10...sidewall surface, 11...decorative area, 12...inner diameter side line, 13...outer diameter side line, 20...profile surface, 21...first plane, 22...second plane, 23...third plane, 24...inter-pair boundary

Claims

1. In a pneumatic tire having a decorative area on a sidewall surface, Three types of planes with different inclinations relative to the profile surface are laid out in the decorative area, Two of the three types of planes are arranged in a first direction to form a pair, A plurality of types of pairs with different combinations are arranged in a second direction, A pneumatic tire, wherein, between the pairs adjacent in the second direction, boundaries between the two planes aligned in the first direction are shifted in the first direction.

2. 2. The pneumatic tire according to claim 1, wherein a step is formed between the planes adjacent in the second direction on a line that passes through the boundary between the two planes aligned in the first direction and extends in the second direction.

3. The pneumatic tire according to claim 1 or 2, wherein a step is formed at a boundary between two of the flat surfaces that are aligned in the first direction and that constitute the pair in at least some of the pairs.

4. The pneumatic tire according to any one of claims 1 to 3, wherein the plane is a rectangle that is long in the tire radial direction.

5. The pneumatic tire according to any one of claims 1 to 4, wherein the decorative region is a band-shaped region that extends once around the tire in the circumferential direction, and a plurality of the flat surfaces are spread over the band-shaped region.

6. The pneumatic tire according to any one of claims 1 to 4, wherein the decorative area is an area having a predetermined shape, and a plurality of the flat surfaces are laid out inside the area having the predetermined shape.

7. The pneumatic tire according to any one of claims 1 to 6, wherein the entire decorative area is recessed from the profile surface of the sidewall surface.

8. The pneumatic tire according to any one of claims 1 to 7, wherein the first direction is a tire radial direction, and the second direction is a tire circumferential direction.

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