Pneumatic tire

Abstract

To provide a pneumatic tire capable of improving low fuel consumption by suppressing air resistance during traveling.SOLUTION: An outer surface of at least one of a pair of sidewall portions 2 is provided with a mark portion 10 and a decorative portion 20 arranged side by side with the mark portion 10 in a tire circumferential direction. In an outer peripheral side region Ro on the outer side in the tire circumferential direction of a tire maximum width position Pm, all of the mark portions 10 and all of the decorative portions 20 are formed of recessed portions 50 recessed inward in a tire axial direction from a profile surface PF of the sidewall portion 2.SELECTED DRAWING: Figure 2

Description

Technical Field

[0001] The present disclosure relates to pneumatic tires.

Background Art

[0002] In recent years, due to environmental problems and the increasing interest in the EV (Electric Vehicle) shift, there has been an increasing demand for improving the low fuel consumption of tires. The low fuel consumption of tires is affected not only by rolling resistance but also by air resistance during driving. Patent Document 1 describes a pneumatic tire that focuses on energy loss due to air resistance.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] In the tire described in Patent Document 1, at least one of the sidewall portions includes a first sector and a second sector located between the crown portion and the axially outermost point. The first sector does not include a raised marking having a height of 0.2 mm or more, while the second sector includes a raised marking having a height of 0.2 mm or more. Since the marking can be a starting point for generating a reverse flow vortex of air, there is room for improvement in suppressing air resistance during driving.

[0005] The present disclosure has been made in view of the above circumstances, and an object thereof is to provide a pneumatic tire capable of suppressing air resistance during driving and improving low fuel consumption.

Means for Solving the Problems

[0006] The pneumatic tire of the present disclosure includes a pair of sidewall portions, and a logo portion and a decorative portion arranged side by side with the logo portion in the tire circumferential direction are provided on at least one outer surface of the pair of sidewall portions. In an outer peripheral side region that is radially outside the tire in the tire diameter direction from the tire maximum width position, all the logo portions and all the decorative portions are formed by recesses that are recessed inward in the tire axial direction from the profile surface of the sidewall portion.

Brief Description of the Drawings

[0007]

Figure 1

Figure 2

Figure 3

Figure 4

Figure 5

Figure 6

Figure 7

Figure 8

Embodiments for Carrying Out the Invention

[0008] Embodiments of the pneumatic tire of the present disclosure will be described with reference to the drawings.

[0009] FIG. 1 is a cross-sectional view schematically showing the pneumatic tire T of the present embodiment. This cross-sectional view shows a cross-section cut by a plane including the central axis of the tire, that is, a tire meridian cross-section. The tire T is a pneumatic tire for an automobile including a pair of bead portions 1, a pair of sidewall portions 2 extending radially outward of the tire from the bead portions 1, and a tread portion 3 continuous with the radially outer ends of each of the sidewall portions 2 in the tire radial direction. The tire T is preferably a pneumatic tire for a passenger car, but may also be a tire of other categories.

[0010] An annular bead core 1a is embedded in the bead portion 1. The bead core 1a is formed by covering a convergent body such as a steel wire with rubber. A bead filler 1b is disposed radially outside the bead core 1a in the tire radial direction. The bead filler 1b is formed of rubber having a triangular cross-section extending radially outward from the bead core 1a.

[0011] Here, the tire radial direction is the direction along the diameter of the tire T and corresponds to the vertical direction in FIG. 1. In FIG. 1, the upper side is the radially outer side of the tire, and the lower side is the radially inner side of the tire. The tire axial direction is the direction parallel to the rotation axis of the tire T and corresponds to the left-right direction in FIG. 1. The inner side in the tire axial direction is the side approaching the tire equator line (not shown) and corresponds to the left side in FIG. 1. The outer side in the tire axial direction is the side away from the tire equator line and corresponds to the right side in FIG. 1. The tire equator line is located at the center in the tire axial direction of the tire T and is a virtual line orthogonal to the tire rotation axis in a plan view. The tire circumferential direction is the direction around the rotation axis of the tire T.

[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 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 example, 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 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 is formed with a tread pattern according to required tire performance and usage conditions.

[0016] The tire maximum width position Pm is the position where the profile surface PF of the sidewall portion 2 is farthest from the tire equator line in the tire axial direction. The profile surface PF is the surface forming the basic contour of the sidewall portion 2 excluding protrusions such as ridges. The profile surface PF is formed by a smooth curved surface that curves convexly outward in the tire axial direction.

[0017] On the outer surface of the sidewall portion 2, the outer peripheral side region Ro is the region outside the tire radial direction of the tire maximum width position Pm, and the inner peripheral side region Ri is the region inside the tire radial direction of the tire maximum width position Pm. Around the tire during running, the air flowing from the front side to the rear side in the traveling direction contacts the outer peripheral side region Ro of the tread portion 3 and the sidewall portion 2, and then tends to peel off near the tire maximum width position Pm. Therefore, in the outer peripheral side region Ro, the contribution to the air resistance during running, particularly the pressure resistance, is larger than that in the inner peripheral side region Ri.

[0018] The mold parting position Ps is set outside the tire radial direction of the tire maximum width position Pm. The mold parting position Ps is the boundary (parting position) between the tread mold for molding the tread portion 3 and the side mold for molding the sidewall portion 2. The mold parting position Ps is identified from the parting line generated on the outer surface of the sidewall portion 2. The parting line is a protruding mold mark generated at the parting position. The outer peripheral side region Ro is the region between the tire maximum width position Pm and the mold parting position Ps.

[0019] The rim line RL is set radially inward of the tire diameter direction from the tire maximum width position Pm. The rim line RL is formed by a projection extending annularly along the tire circumferential direction. The rim line RL is used to confirm that the bead portion 1 is correctly mounted on the rim when the tire T is assembled to the wheel. The inner circumferential side region Ri is a region between the tire maximum width position Pm and the rim line RL. Although not shown in FIG. 1, in the present embodiment, three circumferential projections 41 to 43 protruding outward in the tire axial direction are provided between the mold cut position Ps and the rim line RL.

[0020] FIG. 2 is a view showing a part of the outer surface of the sidewall portion 2, and is a view of the region between the mold cut position Ps and the circumferential projection 43 as seen from the outside in the tire axial direction. As shown in FIG. 2, in this tire T, a logo portion 10 and a decoration portion 20 arranged side by side with the logo portion 10 in the tire circumferential direction are provided on at least one of the outer surfaces of the pair of sidewall portions 2. In the present embodiment, the logo portion 10 and the decoration portion 20 are provided in a belt-like region BR extending along the tire circumferential direction. The belt-like region BR is set between the circumferential projection 41 and the circumferential projection 42.

[0021] The logo portion 10 is composed of a logo such as letters, numbers, symbols or figures, and displays information such as tire size, manufacturer name, and variety. The decoration portion 20 is composed of a decorative figure, pattern, etc., and does not include the information as described above. In the present embodiment, the decoration portion 20 includes a serration 30 in which ridges 31 as described later are arranged (see FIG. 3(B)). In the serration 30, the unevenness associated with the ridges 31 causes a shadow of the color (black) of the sidewall rubber 8 to produce a decorative effect. However, it is not limited to this, and the decoration portion 20 may have a structure that does not include such a serration 30.

[0022] The emblem part 10 and the decoration part 20 are each provided at a plurality of locations (four locations in this embodiment) in the tire circumferential direction, and they are alternately arranged along the tire circumferential direction. The sum of the opening angles θ10 of each of the emblem parts 10 provided at the plurality of locations and the sum of the opening angles θ20 of each of the decoration parts 20 provided at the plurality of locations are, for example, 120 degrees or more.

[0023] FIG. 3(A) is a cross-sectional view taken along the line A-A of FIG. 2, showing the cross-section of the emblem that constitutes the emblem part 10. As shown in FIG. 3(A), the emblem part 10 is formed by a recessed portion 50 that is recessed inward in the tire axial direction from the profile surface PF. Other emblem parts 10 have the same cross-section as this. FIG. 3(B) is a cross-sectional view taken along the line B-B of FIG. 2 (see also FIG. 5), showing the cross-section of the pattern that constitutes the decoration part 20. As shown in FIG. 3(B), the decoration part 20 is formed by a recessed portion 50 that is recessed inward in the tire axial direction from the profile surface PF. Other decoration parts 20 have the same cross-section as this.

[0024] Therefore, in the outer peripheral side region Ro that is radially outside the tire diameter from the tire maximum width position Pm, all the emblem parts 10 and all the decoration parts 20 are formed by the recessed portion 50 that is recessed inward in the tire axial direction from the profile surface PF. In other words, all the portions of the emblem part 10 and the decoration part 20 arranged in the outer peripheral side region Ro are formed by the recessed portion 50. According to such a configuration, in the outer peripheral side region Ro where the contribution to the air resistance during running is large, all the undulations by the emblem part 10 and the decoration part 20 become concave shapes, so that the air resistance during running can be suppressed and the improvement of low fuel consumption can be achieved.

[0025] The belt-like region BR is provided as an annular region having a constant width and extending over the entire circumference in the tire circumferential direction. The belt-like region BR is formed in a constant region in the tire radial direction including the tire maximum width position Pm. The emblem part 10 and the decoration part 20 are arranged straddling the tire maximum width position Pm in the tire radial direction. In the present embodiment, all the emblem parts 10 and all the decoration parts 20 provided in the belt-like region BR are formed by the recesses 50. In other words, all parts of the emblem part 10 and the decoration part 20 provided in the belt-like region BR are formed by the recesses 50. Incidentally, serrations 30 are arranged in the recesses 50 forming the decoration part 20.

[0026] From the viewpoint of ensuring the visibility of the emblem part 10 and the decoration part 20, the depth D50 of the recess 50 with respect to the profile surface PF is preferably 0.2 mm or more. Also, from the viewpoint of suppressing the air resistance during running, the depth D50 is preferably 0.5 mm or less, and more preferably 0.4 mm or less. This is because if the undulation due to the recess 50 becomes excessively large, a relatively large air vortex is generated when air escapes from the recess 50, and the effect of suppressing air resistance may be reduced.

[0027] FIG. 3(C) is a cross-sectional view taken along the line C-C of FIG. 2, and shows a cross-section of a portion surrounding the emblem part 10 and the decoration part 20. As shown in FIG. 3(C), the periphery of the emblem part 10 and the decoration part 20 is formed by a smooth surface 60. The smooth surface 60 is a smooth surface without irregularities such as protrusions, and no decoration such as ridges is applied. Although not shown in the drawing, the smooth surface 60 is curved along the profile surface PF. In the present embodiment, the smooth surface 60 substantially coincides with the profile surface PF.

[0028] Outside the tire radial direction from the maximum tire width position Pm, the surroundings of all the emblem parts 10 and all the decorative parts 20 are formed by the smooth surface 60. In other words, in all the parts of the emblem part 10 and the decorative part 20 that are arranged outside the tire radial direction from the maximum tire width position Pm, the surroundings thereof are formed by the smooth surface 60. According to such a configuration, in a region where the contribution to the air resistance during running is large, the undulations around the emblem part 10 and the decorative part 20 are reduced, so that the air resistance during running can be suppressed and the improvement of low fuel consumption can be achieved. In the present embodiment, in the belt region BR, all the parts except the emblem part 10 and the decorative part 20 are formed by the smooth surface 60.

[0029] Reducing the undulations of the outer surface by the smooth surface 60 is effective in suppressing the air resistance during running. However, when the surface roughness of the smooth surface 60 is excessively small, the viscous resistance increases due to the adhesion of the air flowing along the outer surface of the sidewall part 2, and the air flow velocity tends to decrease. As a result, the velocity difference between the air layer close to the outer surface of the sidewall part 2 and the air layer far from it becomes large, the air separation occurs early, and the pressure resistance may increase. From such a viewpoint, it is desirable to make the surface roughness of the smooth surface 60 moderately large. For example, the arithmetic mean roughness Ra of the smooth surface 60 is preferably 1.0 μm or more.

[0030] Also, it is desirable to make the surface roughness of the smooth surface 60 moderately small so as not to generate a reverse flow vortex of air due to the minute irregularities on the smooth surface 60. For example, the arithmetic mean roughness Ra of the smooth surface 60 is preferably 2.4 μm or less. Therefore, the arithmetic mean roughness Ra of the smooth surface 60 is set to, for example, 1.7 ± 0.7 μm. The arithmetic mean roughness Ra is defined in JIS B0601:2013, and the evaluation method and procedure thereof conform to the provisions of JIS B0633:2001.

[0031] In the outer peripheral region Ro, a circumferential projection 41 extending annularly along the tire circumferential direction is provided. The band region BR is provided radially inward of the tire diameter than the circumferential projection 41. The circumferential projection 41 is arranged radially inward of the tire diameter than the mold split position Ps. In the inner peripheral region Ri, circumferential projections 42 and 43 extending annularly along the tire circumferential direction are provided. The band region BR is provided radially outward of the tire diameter than the circumferential projection 42. The band region BR is provided between a pair of circumferential projections 41 and 42 protruding outward in the tire axial direction.

[0032] In the inner peripheral region Ri, since the contribution to the air resistance during running is small, a logo portion or a decorative portion protruding outward in the tire axial direction than the profile surface PF may be provided. In the present embodiment, a logo portion 70 for displaying information such as the manufacturing year and week is provided radially inward of the tire diameter than the circumferential projection 42, and this logo portion 70 protrudes outward in the tire axial direction than the profile surface PF.

[0033] As shown in FIG. 3, the wall surface 51 of the recess 50 is inclined in a direction to expand the opening of the recess 50. The angle θ51 of the wall surface 51 with respect to the normal line of the profile surface PF is preferably 15 degrees or more. Thereby, air can easily escape smoothly from the recess 50, and the generation of a reverse flow vortex starting from the wall surface 51 can be suppressed, which is convenient for suppressing the air resistance during running. Further, from the viewpoint of clarifying the contour of the logo portion 10 or the decorative portion 20 and ensuring visibility, the angle θ51 is preferably 45 degrees or less.

[0034] FIG. 4 is an enlarged view showing the main part of FIG. 2. FIG. 5 is a cross-sectional view taken along the line X-X of FIG. 4, showing a cross-section along a direction orthogonal to the extending direction of the ridge 31. FIG. 6 is a cross-sectional view taken along the line Y-Y of FIG. 4, showing a cross-section along a direction parallel to the extending direction of the ridge 31. As described above, in the present embodiment, a serration 30 in which the ridges 31 are arranged is disposed in the recess 50 forming the decorative portion 20. The serration 30 is disposed in a recess 50 that is recessed inward in the tire axial direction from the profile surface PF of the sidewall portion 2, and protrudes with a protrusion height Ph of 0.1 mm or less from the profile surface PF.

[0035] In the present embodiment, a part of the serration 30 is disposed in the inner peripheral side region Ri. In a single serration 30, the area of the portion disposed in the outer peripheral side region Ro is larger than the area of the portion disposed in the inner peripheral side region Ri. However, the present invention is not limited to this, and all of the serration 30 may be disposed in the outer peripheral side region Ro.

[0036] The ridge 31 bulges outward in the tire axial direction from the bottom surface of the recess 50. The ridge 31 has a height H31 from the bottom connected to the bottom surface of the recess 50 to the top. The height H31 is set to be substantially constant along the extending direction of the ridge 31. The height H31 of the ridge 31 is larger than the depth D50 of the recess 50 (i.e., H31 > D50), and the difference therebetween corresponds to the protrusion height Ph. The protrusion height Ph is the height of the serration 30 (the ridge 31 forming the serration 30) with respect to the profile surface PF.

[0037] Since the shadow becomes thinner as the height H31 becomes smaller, it is effective to ensure the height H31 of the ridge 31 in order to ensure the decorative effect. In this tire T, since the serration 30 is disposed in the recess 50, the height H31 can be ensured without protruding the ridge 31 greatly from the profile surface PF, and it is easy to ensure the decorative effect by the serration 30.

[0038] In the tire T, although the serration 30 protrudes from the profile surface PF, the protrusion height Ph is slight, specifically 0.1 mm or less. Therefore, compared with the form in which the serration protrudes greatly from the profile surface, the air resistance during running can be suppressed. Further, the structure in which the serration 30 protrudes slightly in this way is also effective in suppressing the air resistance during running compared with the structure in which the serration does not protrude from the profile surface (reference example described later), as will be described with reference to FIGS. 7 and 8. Therefore, according to this tire T, while ensuring the decorative effect by the serration 30, it is possible to suppress the air resistance during running and improve the fuel efficiency.

[0039] FIG. 7 shows the serration 30c in the reference example. The serration 30c is disposed in the recess 50c recessed from the profile surface PF and does not protrude from the profile surface PF. FIG. 8 shows the serration 30 in the present embodiment. As described above, the serration 30 is disposed in the recess 50 recessed from the profile surface PF and slightly protrudes from the profile surface PF. FIGS. 7 and 8 respectively show a cross-sectional view (A) along a direction orthogonal to the extending direction of the ridge, a perspective view (B), and a cross-sectional view (C) along a direction parallel to the extending direction of the ridge.

[0040] In FIGS. 7 and 8, the air flow is schematically represented by arrows. Around the tire during running, air flows from the front side to the rear side in the traveling direction, and since the direction of the ridge with respect to the traveling direction changes according to the rolling of the tire, it is considered separately into a scene where air flows in a direction orthogonal to the extending direction of the ridge and a scene where air flows in a direction parallel to the extending direction of the ridge. The behavior of the air in the former is shown in (A), and the behavior of the air in the latter is shown in (B) and (C).

[0041] From the perspective of ensuring the decorative effect, the ridge 31c in the reference example is set to the same height as the ridge 31 in the present embodiment. Therefore, the depth D50c of the recess 50c in the reference example is greater than the depth D50 of the recess 50 in the present embodiment (i.e., D50c > D50). In the reference example, since the undulation is relatively large and the serration 30c does not protrude, air is likely to penetrate deeply into the recess 50c. In contrast, in the present embodiment, since the undulation is relatively small and the serration 30 protrudes, air is less likely to penetrate deeply into the recess 50 compared to the reference example.

[0042] FIG. 7(A) shows a state in which air that has penetrated deeply into the recess 50c rises along the ridge 31c to form a relatively large air vortex. FIG. 7(B) shows a state in which turbulent air flow occurs inside the recess 50c because the serration 30c does not protrude. FIG. 7(C) shows a state in which air rises along the wall surface of the recess 50c with a large undulation to form a relatively large air vortex. In the reference example, such behavior tends to make the air flow unstable, and if air separation occurs at or near the serration 30c due to this, it may cause an increase in pressure resistance.

[0043] FIG. 8(A) shows a state in which air contacts the top of the ridge 31 and slightly rises before entering the recess 50 to form a relatively small air vortex. FIG. 8(B) shows a state in which the serration 30 (of the ridge 31) protruding from the profile surface PF functions as a guide and air rectification occurs inside the recess 50. FIG. 8(C) shows a state in which air rises along the wall surface of the recess 50 with a small undulation to form a relatively small air vortex. In the present embodiment, such behavior tends to make the air flow stable, and by separating the air further rearward, the pressure resistance can be suppressed compared to the reference example.

[0044] The height H31 of the ridge 31 is set to, for example, 0.3 to 0.5 mm. From the viewpoint of appropriately achieving the above-described effects, the protrusion height Ph is preferably 0.03 mm or more, more preferably 0.06 mm or more. The protrusion height Ph is set to, for example, 10% or more and less than 50% of the height H31 of the ridge 31.

[0045] The shape of the ridge 31 as viewed along the extending direction is preferably a shape in which the width gradually increases toward the inner side in the tire axial direction, and particularly preferably a triangular shape. With such a configuration, the shadow can be made prominent (darkened) to ensure a good decorative effect. This triangular shape includes a triangular shape with a rounded top (see FIG. 5), and the radius of curvature R31 of the top is, for example, 0.3 mm or less. The opening angle θs is, for example, 90 ± 45 degrees. In the present embodiment, the adjacent ridges 31 are arranged so as to be in contact with each other, but the present invention is not limited to this, and they may be arranged with a space therebetween.

[0046] As shown in FIG. 4, in the present embodiment, the ridge 31 extends in a direction intersecting the tire circumferential direction. According to such a configuration, since a shadow is likely to be generated, it is convenient for ensuring the decorative effect by the serration 30.

[0047] The tire T of the present embodiment is configured as a so-called rotation direction specified type tire in which the rotation direction is specified. The rotation direction is specified by a display provided on the outer surface of the sidewall portion 2. The arrow RD1 in the drawing indicates the front side in the rotation direction, and the arrow RD2 indicates the rear side in the rotation direction. Note that the tire T is not limited to the rotation direction specified type tire.

[0048] As shown in FIG. 4, in the outer peripheral region Ro, the recess 50 has a curved contour that bulges forward in the rotational direction RD1. According to such a configuration, small air vortices can be generated in the outer peripheral region Ro that makes a large contribution to air resistance, and air separation can be suppressed. In the outer peripheral region Ro, the recess 50 extends in a direction inclined radially outward in the tire diameter direction toward the rear side RD2 in the rotational direction, and is tapered toward the rear side RD2 in the rotational direction. In the outer peripheral region Ro, a plurality (three in this embodiment) of the recesses 50 having such a shape are arranged at intervals in the tire circumferential direction.

[0049] As shown in FIG. 4, in this embodiment, in the outer peripheral region Ro, the ridge 31 extends in a direction inclined with respect to the tire diameter direction. Further, the ridge 31 extends in a direction inclined radially inward in the tire diameter direction toward the rear side RD2 in the rotational direction, and is inclined in the opposite direction to the recess 50. That is, the ridge 31 extends in a direction inclined in the opposite direction to the recess 50 with respect to the tire diameter direction. According to such a configuration, since the appearance of the shadow changes due to the difference in light reflection depending on the viewing direction, the visibility of the design formed by the recess 50 can be improved.

[0050] In this embodiment, a pattern (decoration part 20) composed of a plurality of recesses 50 as shown in FIG. 4 is formed at a plurality of locations (specifically, four locations) in the tire circumferential direction as shown in FIG. 2. Therefore, while ensuring the decorative effect by the sipe 30, the effect of suppressing air resistance during running and improving fuel efficiency can be obtained more favorably. In this embodiment, the sipe 30 is provided in a belt-like region BR extending along the tire circumferential direction.

[0051] The logo part 10 and the decoration part 20 as described above may be provided on the outer surface of at least one of the pair of sidewall parts 2.

[0052] Unless otherwise specified, dimensions, angles, positional relationships, etc. of each part of the tire shall be determined in a non-loaded state where the tire mounted on the regular rim is filled with the regular internal pressure. The regular rim is the rim defined for each tire in the standard system including the standard on which the tire is based. For example, it is the standard rim in JATMA, and "Measuring Rim" in TRA and ETRTO.

[0053] The regular internal pressure is the air pressure defined for each tire in the standard system including the standard on which the tire is based. For truck and bus tires and light truck tires, in JATMA it is the maximum air pressure, in TRA it is the value corresponding to the Load Index described in the table "TIRE LOAD LIMITS AT VARIOUS COLD INFLATION PRESSURES", and in ETRTO it is "INFLATION PRESSURE". For passenger car tires, it is usually 250 kPa, but for tires marked as Extra Load or Reinforced, it is 290 kPa.

[0054] Those skilled in the art will understand that the above-described embodiments are specific examples of the following aspects.

[0055] [1] The pneumatic tire of the present disclosure includes a pair of sidewall portions, and on the outer surface of at least one of the pair of sidewall portions, there are provided a logo portion and a decorative portion arranged side by side in the tire circumferential direction. In the outer peripheral side region that is radially outside the tire maximum width position, all the logo portions and all the decorative portions are formed by recesses that are recessed inward in the tire axial direction from the profile surface of the sidewall portion. According to such a configuration, in the outer peripheral side region where the contribution to the air resistance during running is large, all the undulations by the logo portion and the decorative portion become concave shapes, so that the air resistance during running can be suppressed and the improvement of low fuel consumption can be achieved.

[0056] [2] In the pneumatic tire of the above [1], outside the tire radial direction from the tire maximum width position, the circumferences of all the said emblem parts and all the said decorative parts may be formed by smooth surfaces. According to such a configuration, in the region that contributes greatly to the air resistance during running, the undulations around the emblem part and the decorative part become small, so that the air resistance during running can be suppressed and the improvement of fuel efficiency can be achieved.

[0057] [3] In the pneumatic tire of the above [1] or [2], the said emblem part and the said decorative part are provided in a belt-shaped region extending along the tire circumferential direction, and in the said belt-shaped region, all parts except the said emblem part and the said decorative part may be formed by smooth surfaces. According to such a configuration, the undulations of the part excluding the emblem part and the decorative part in the belt-shaped region become small, so that the air resistance during running can be suppressed and the improvement of fuel efficiency can be achieved.

[0058] [4] In the pneumatic tire of the above [3], in the said outer peripheral side region, a circumferential projection extending annularly along the tire circumferential direction is provided, and the said belt-shaped region may be provided inside the tire radial direction from the said circumferential projection.

[0059] [5] In the pneumatic tire of any one of the above [1] to [4], the wall surface of the said recess is inclined in the direction of expanding the opening of the said recess, and the angle of the said wall surface with respect to the normal line of the said profile surface may be 15 degrees or more. According to such a configuration, air can easily escape smoothly from the recess, and the generation of a reverse flow vortex starting from the wall surface can be suppressed, which is convenient for suppressing the air resistance during running.

[0060] The pneumatic tire T of the present disclosure can be configured in the same manner as a normal pneumatic tire except that the sidewall part 2 is configured as described above, and any conventionally known shape, material, etc. can be adopted.

[0061] Although the embodiments of the present disclosure have been described with reference to the drawings, the specific configuration should not be considered to be limited to this embodiment. The scope of the present disclosure is shown not only by the description of the above embodiments but also by the scope of the claims, and further includes all modifications within the meaning and scope equivalent to the scope of the claims.

[0062] The pneumatic tire of the present disclosure is not limited to the above-described embodiments at all, nor is it limited to the above-described effects. The tire of the present disclosure can be variously improved and modified within the scope not departing from its gist. In addition, each configuration adopted in the above-described embodiments can be arbitrarily combined and adopted.

Explanation of Signs

[0063] 2 Sidewall part 10 Emblem part 20 Decorative part 30 Siping 31 Ridge 50 Recess 51 Wall surface 60 Smooth surface

Claims

1. Comprising a pair of side wall portions, On at least one outer surface of the pair of side wall portions, a logo portion and a decorative portion arranged side by side in the tire circumferential direction are provided, In an outer peripheral side region that is radially outside the tire in the tire diameter direction from the tire maximum width position, all of the logo portions and all of the decorative portions are formed by recesses that are recessed inward in the tire axial direction from the profile surface of the side wall portion, a pneumatic tire.

2. Outside the tire in the tire diameter direction from the tire maximum width position, the circumferences of all of the logo portions and all of the decorative portions are formed by smooth surfaces, the pneumatic tire according to Claim 1.

3. The logo portion and the decorative portion are provided in a belt-like region extending along the tire circumferential direction, In the belt-like region, all portions excluding the logo portion and the decorative portion are formed by smooth surfaces, the pneumatic tire according to Claim 1.

4. In the outer peripheral side region, a circumferential projection extending annularly along the tire circumferential direction is provided, The belt-like region is provided radially inside the tire from the circumferential projection, the pneumatic tire according to Claim 3.

5. The wall surface of the recess is inclined in a direction to expand the opening of the recess, The angle of the wall surface with respect to the normal line of the profile surface is 15 degrees or more, the pneumatic tire according to any one of Claims 1 to 4.

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