Pneumatic tire and mold for molding pneumatic tire

Abstract

To provide a pneumatic tire capable of achieving balance in high performance of suppression of rise of internal heat generation, reduction of air resistance, and braking performance and steering stability on a wet road surface, and easily generating contrast on a tire side surface.SOLUTION: A tire includes an undulating curved surface that is provided on a tire side surface, which is an outer surface in a tire axial direction inside a ground contact end of a tread in a tire radial direction and outside a rim line in the tire radial direction, and that undulates in the tire radial direction and a tire circumferential direction so as to have a plurality of mountain-shaped protrusions in the tire radial direction and the tire circumferential direction. A plurality of curved surface protrusions is provided on a surface of the undulating curved surface.SELECTED DRAWING: Figure 2

Description

[Technical Field]

[0001] The present invention relates to a pneumatic tire and a mold for molding a pneumatic tire, and more particularly to a pneumatic tire having an undulating curved surface provided on a tire side surface, which is an axially outer surface of the tire radially outward from the rim line. [Background technology]

[0002] In recent years, providing multiple protrusions on the side of a tire has been considered in order to improve the design of the tire. For example, Patent Document 1 describes providing multiple cylindrical protrusions that protrude from the surface of the sidewall and generate turbulence. Patent Document 1 states that turbulence is generated by the edges at the connection points between the tip surfaces of the protrusions and the sidewall surface.

[0003] Patent Document 2 describes that a plurality of protrusions that protrude outward from the tire are regularly arranged on the surface of the tire side, the maximum width and maximum height of the protrusions are within a predetermined range, and the arrangement interval of the protrusions along the tire surface is greater than 0.1 μm and less than 100 μm, which is said to form an optimal air relaxation layer on the tire surface.

[0004] Patent Document 3 describes a configuration in which a tire sidewall is formed with a plurality of mountain-shaped protrusions with varying heights and minute pitches, resulting in an overall undulating shape that is inclined relative to the tire circumferential direction, which is said to improve the rigidity of the sidewall. [Prior art documents] [Patent documents]

[0005] [Patent Document 1] International Publication No. 2008 / 096879 [Patent Document 2] Japanese Patent Application Laid-Open No. 2013-169827 [Patent Document 3] Chinese Patent Application Publication No. 107499068 Summary of the Invention [Problem to be solved by the invention]

[0006] The configurations described in Patent Documents 1 to 3 have room for improvement in terms of achieving a balance between suppressing an increase in internal heat generation, reducing air resistance, and improving braking performance and handling stability on wet roads in pneumatic tires, as well as making it easier to create contrast on the tire side surface. [Means for solving the problem]

[0007] The pneumatic tire according to the present invention is a pneumatic tire having an undulating curved surface that is provided on the tire side surface, which is the axially outer surface of the tire, radially inward from the ground-contact edge of the tread and radially outward from the rim line, and that undulates in the tire radial and circumferential directions so as to have a plurality of angle-shaped protrusions in the tire radial and circumferential directions, and a plurality of curved protrusions are provided on the surface of the undulating curved surface.

[0008] The pneumatic tire molding mold according to the present invention is a pneumatic tire molding mold for molding the pneumatic tire according to the present invention, and has a mold-side curved surface on the molding surface that corresponds to the undulating curved surface, and a plurality of curved surface inner recesses that correspond to the curved surface protrusions are formed on the mold-side curved surface. [Effects of the Invention]

[0009] The pneumatic tire and pneumatic tire mold according to the present invention can suppress an increase in internal heat generation by increasing the tire surface area with an undulating curved surface, and can suppress the generation of turbulence by using a curved surface shape with no or few edges, thereby reducing air resistance. Furthermore, wet braking performance, i.e., braking performance on wet roads, can be improved without compromising the tire's wear resistance and handling stability. Furthermore, the multiple protrusions on the curved surface make it easier to create contrast on the tire side surface. [Brief explanation of the drawings]

[0010] [Figure 1] 1 is a diagram showing a tire contour shape in a meridian cross section of a pneumatic tire that is an example of an embodiment, and is a diagram showing a range in which an undulating surface is formed. FIG. [Figure 2] 1 is a perspective view showing a part in the tire circumferential direction of a pneumatic tire according to an embodiment, cut away from other parts. [Figure 3] FIG. 2 is a perspective view showing a partially cutaway annular portion that forms an undulating curved surface in the embodiment. [Figure 4] FIG. 2 is an enlarged cross-sectional view of part A in FIG. [Figure 5] 1 is a schematic diagram showing the positions of peaks and valleys in a portion of an undulating surface in the tire circumferential direction in a pneumatic tire according to an embodiment. FIG. [Figure 6] FIG. 4 is a schematic view seen in the direction of arrow B in FIG. 3. [Figure 7] FIG. 10 is an enlarged perspective view of a curved surface protrusion provided on a wavy curved surface in the embodiment. [Figure 8] 8 is a view of the curved projection of FIG. 7 as seen from the outside in the height direction. [Figure 9] FIG. 10 is a schematic diagram showing that, in an embodiment, after an air flow collides with a curved protrusion, turbulence causes the air flow to reattach to another curved protrusion downstream, and the separation point is likely to be downstream. [Figure 10] FIG. 10 is a schematic diagram showing that, in another example of the embodiment, a wavy curved surface does not generate turbulence in the same way as a smooth surface. [Figure 11] FIG. 10 is a schematic diagram illustrating, by using a cylinder Sa, the generation of a wake region due to a separated air flow downstream of a tire side surface in the air flow in another example of the embodiment. [Figure 12] FIG. 10 is a schematic diagram illustrating, using a cylinder S as a simulation, how the width of the wake region caused by the separated air flow narrows downstream of the tire side surface in the air flow, increasing the negative pressure reduction effect in an embodiment. [Figure 13] FIG. 2 is a cross-sectional view showing a mold for molding a pneumatic tire in an embodiment. [Figure 14]10A and 10B are diagrams illustrating protrusions on a curved surface in a pneumatic tire according to another embodiment. [Figure 15] 10A and 10B are diagrams illustrating protrusions on a curved surface in a pneumatic tire according to another embodiment. [Figure 16] 10A and 10B are diagrams illustrating protrusions on a curved surface in a pneumatic tire according to another embodiment. [Figure 17] 10A and 10B are diagrams illustrating protrusions on a curved surface in a pneumatic tire according to another embodiment. [Figure 18] FIG. 10 is a perspective view showing a curved surface protrusion in a pneumatic tire according to another embodiment. [Figure 19] 19 is a view seen in the direction of arrow C in FIG. 18. [Figure 20] FIG. 20 is a cross-sectional view taken along the line DD in FIG. 19. [Figure 21] 19 is a cross-sectional view of FIG. [Figure 22] 10 is a view of a curved projection of a pneumatic tire according to another embodiment as viewed from the outside in the height direction. FIG. [Figure 23] 10 is a view of a curved projection of a pneumatic tire according to another embodiment as viewed from the outside in the height direction. FIG. [Figure 24] 10 is a view of a curved projection of a pneumatic tire according to another embodiment as viewed from the outside in the height direction. FIG. [Figure 25] FIG. 6 is a view corresponding to FIG. 5, showing a pneumatic tire according to another embodiment. [Figure 26] FIG. 26 is a schematic diagram showing that the light absorption effect is produced by the configuration of FIG. 25. [Figure 27] FIG. 10 is a schematic diagram showing the positions of peaks and valleys in a portion of an undulating surface in the tire circumferential direction in a pneumatic tire according to another embodiment. DETAILED DESCRIPTION OF THE INVENTION

[0011] Hereinafter, an example of an embodiment of a pneumatic tire and a mold for molding the same according to the present invention will be described in detail with reference to the drawings. The embodiment described below is merely an example, and the present invention is not limited to the following embodiment. Furthermore, the present invention includes selective combinations of the respective components of the multiple embodiments and modified examples described below.

[0012] FIG. 1 is a diagram showing a tire contour shape in a meridian cross section of a pneumatic tire 1 according to an embodiment, illustrating the range in which an undulating surface is formed. FIG. 2 is a perspective view showing a circumferential portion of the pneumatic tire 1 cut away from other portions. As shown in FIGS. 1 and 2, the pneumatic tire 1 includes a tread 10, which is a portion that comes into contact with the road surface. Hereinafter, the "pneumatic tire 1" will be referred to as the "tire 1." The tread 10 has a tread pattern including multiple blocks and is formed in an annular shape along the tire circumferential direction. While FIG. 1 shows the tread 10 as being formed of a single block, in reality, as shown in FIG. 2, the tread 10 includes multiple blocks 11a, 11b separated in the tire axial direction X. The multiple blocks 11a, 11b are separated by circumferential grooves 11c (FIG. 2) extending in the tire circumferential direction. The tread 10 has a ground contact edge T. In FIGS. 1 and 2, the tire axial direction is indicated by X, the tire radial direction is indicated by Y, and the tire circumferential direction is indicated by α.

[0013] Hereinafter, the configuration of the tire 1 will be described mainly with respect to the vehicle outer side (OUT side) portion with respect to the center CL in the tire axial direction X. The tire 1 is symmetrical between the vehicle outer side portion and the vehicle inner side portion with respect to the shape other than the annular portion 100 provided with the undulating curved surface of the tire side surface, which will be described later. Meanwhile, the vehicle inner side portion (IN side) of the tire may also be provided with the same annular portion 100 as the vehicle outer side portion.

[0014] The tire 1 includes a sidewall 12 located at an outer end of the tread 10 in the tire axial direction X and bulging outward most in the tire axial direction X, and a bead 15 ( FIG. 2 ) fixed to a wheel rim. The sidewall 12 and the bead 15 are formed in an annular shape along the tire circumferential direction. The sidewall 12 extends inward in the tire radial direction Y from both ends of the tread 10 in the tire axial direction X. A rim strip 18 is provided at the inner end of the tire 1 in the radial direction Y, adjacent to the sidewall 12, and forming the outer surface of the bead 15.

[0015] The tire 1 is a pneumatic tire filled with air at a predetermined pressure. The tread 10 is made of tread rubber. The sidewall 12 is made of a different type of sidewall rubber than the tread rubber.

[0016] In this specification, unless otherwise specified, the dimensions of each part of a tire are dimensions measured when an unused tire is mounted on a standard rim, inflated to the standard internal pressure, and in a standard, unloaded state.

[0017] "Touching edge T" refers to both ends in the axial direction X of the tire in the area that comes into contact with a flat road surface when an unused tire 1 is mounted on a standard rim, inflated to the standard internal pressure, and subjected to a load that is 88% of the standard load at the standard internal pressure.

[0018] Here, a "regular rim" is a rim specified by the tire standard, and is a "standard rim" for JATMA, a "design rim" for TRA, and a "measuring rim" for ETRTO. "Regular internal pressure" is the "maximum air pressure" for JATMA, the maximum value listed in the "TIRE LOAD LIMITS AT VARIOUS COLD INFLATION PRESSURES" table for TRA, and "INFLATION PRESSURE" for ETRTO. "Regular load" is the "maximum load capacity" for JATMA, the maximum value listed in the "TIRE LOAD LIMITS AT VARIOUS COLD INFLATION PRESSURES" table for TRA, and "LOAD CAPACITY" for ETRTO.

[0019] The tire 1 comprises a carcass, a belt layer, and an inner liner. The carcass is a cord layer covered with rubber, and forms the framework of the tire 1 that can withstand loads, impacts, air pressure, etc. The belt layer is a reinforcing band placed between the tread rubber and the carcass. The belt layer tightens the carcass to increase the rigidity of the tire 1. The belt layer is formed by overlapping multiple belts in the tire radial direction Y. Each belt is formed by multiple cords arranged in a direction inclined relative to the tire circumferential direction and covered with rubber. The cords of adjacent belts are inclined in opposite directions relative to the tire circumferential direction so that they cross each other. The cords are made of steel or the like.

[0020] A belt reinforcing layer is provided between the belt layer and the tread rubber, extending in the tire circumferential direction and covering the entire belt layer in the tire axial direction X. The belt reinforcing layer is formed by covering cords extending substantially in the tire circumferential direction with rubber. The cords are made of organic fibers or the like.

[0021] In the tire 1 of the embodiment, the mounting direction of the front and back of the tire 1 on the vehicle is specified. That is, the outer and inner sides of the vehicle are respectively specified for the tire 1. In Fig. 1, the tire 1 is mounted on the vehicle so that the right side is the outer side (OUT side) of the vehicle and the left side is the inner side (IN side) of the vehicle.

[0022] A symbol called a serial number is generally provided on the side of a tire. The serial number includes information such as a size code, manufacturing date (manufacturing year and week), and manufacturing location (manufacturing factory code). The mounting direction of the tire 1 on the vehicle can be specified by providing a serial number only on the tire side (sidewall 12) facing the outside of the vehicle, or by providing different serial numbers on the side facing the outside of the vehicle and the side facing the inside of the vehicle. A specific example is to provide a manufacturing factory code and a size code on both sides of the tire 1, and provide the manufacturing year and week only on the side facing the outside of the vehicle width direction.

[0023] In addition, a marking such as a letter or symbol may be provided on the side of the tire facing outward from the vehicle to indicate that the tire is on the outside when mounted on the vehicle.

[0024] Furthermore, a rim protector 19 that protrudes axially outward is provided as part of the rim strip rubber that forms the rim strip 18. The rim line 20 is provided in an annular shape along the circumferential direction of the tire at the apex of the rim protector 19 that is located at the axially outer end of the tire. The rim protector 19 has the function of protecting the rim from external damage. The rim line 20 is a line that can be used to check the gap between the tire 1 and the rim to ensure that the tire 1 is properly mounted on the rim. Although the rim protector 19 is provided in Figure 1, the configuration may also be such that the rim protector 19 is not provided, as indicated by the two-dot chain line in Figure 1. Even in this case, a rim line, which is a circular protrusion that protrudes axially outward, is provided on the side of the tire to ensure that the tire 1 is properly mounted on the rim.

[0025] In this example, an annular portion 100 including a undulating surface 30 is provided on a tire side surface 13, which is the outer surface in the tire axial direction X, located inside the ground contact edge T of the tread 10 in the tire radial direction Y and outside the rim line 20 in the tire radial direction Y.

[0026] As shown in FIG. 2 , a tire side surface 13 facing the vehicle outboard has an annular portion 100 whose length in the tire radial direction is constant over the entire circumference in the tire circumferential direction. The annular portion 100 is formed by a undulating surface 30 that protrudes axially outward from the bottom of an annular recessed portion 37. The undulating surface 30 undulates in the tire radial and circumferential directions so as to have a plurality of angled protrusions 35 in the tire radial and circumferential directions. The peaks 31 of the angled protrusions 35 that protrude furthest outward from the tire and the valleys 38 that are recessed furthest toward the tire inboard side are each provided at the same pitch over the entire tire circumferential direction and at the same pitch in the tire radial direction. Note that, as will be described later, the tire of the present invention may be configured to have, instead of the annular portion 100 having an annular recessed portion 37 with an annular undulating surface formed on the inside, an arc-shaped portion provided at one or more positions in the tire circumferential direction of the tire side surface and having an arc-shaped recessed portion with an arc-shaped undulating surface formed in the tire circumferential direction.

[0027] Fig. 3 is a perspective view showing a partial cutaway of the annular portion 100, which is the portion forming the undulating surface 30, in an embodiment. Fig. 4 is an enlarged cross-sectional view of portion A in Fig. 1. Fig. 5 is a schematic diagram showing the positions of the peaks 31 and valley points 38 of the angled protrusions 35 in a portion of the undulating surface 30 in the tire circumferential direction in the tire 1. Fig. 6 is a schematic diagram seen in the direction of arrow B in Fig. 3. The undulating surface 30 is formed on the tire side surface 13, inside an annular recessed portion 37 provided along the tire circumferential direction. The annular recessed portion 37 is recessed from the sidewall reference plane 14 (Figs. 2 and 3) toward the tire inner surface with the same radial width in the tire.

[0028] The sidewall reference surface 14 refers to the surface of the tire side surface 13 facing outward in the axial direction of the sidewall 12 in a portion where partial irregularities such as protrusions or recesses of side blocks are not formed.

[0029] The undulating surface 30 is formed to protrude in the tire axial direction inside the annular recess 37 so that valleys and peaks are alternately repeated in the tire circumferential direction and the tire radial direction, with valley points 38 at multiple positions in the tire radial direction on the bottom surface of the annular recess 37 in the tire circumferential direction. As a result, the undulating surface 30 is formed to rise in the tire axial direction from the bottom surface of the annular recess 37. Therefore, the undulating surface 30 changes periodically in the tire circumferential direction and the tire radial direction.

[0030] In this example, as shown in the schematic diagram of Fig. 5, the undulating surface 30 has a plurality of first undulation portions 51 undulating in the tire circumferential direction at a plurality of positions in the tire radial direction, and the phases of the peaks 31 of the plurality of first undulation portions 51 match among the plurality of first undulation portions 51. Furthermore, the phases of the valley points 38 of a plurality of second undulation portions 52 undulating in the tire circumferential direction between adjacent first undulation portions 51 at a plurality of positions in the tire radial direction are located between the peaks 31 of the first undulation portions 51 in the tire circumferential direction. In Fig. 5, a plurality of dashed lines extending in the tire circumferential direction indicate either the first undulation portions 51 or the second undulation portions 52. Fig. 5 corresponds to a portion of the undulation surface 30 in the tire circumferential direction as viewed from the outer side in the tire axial direction, and the insides of a plurality of circles indicate the angle-shaped protrusions 35 of the first undulation portions 51, and the centers of the multiple crosses on the insides of the circles indicate the peaks 31 of the angle-shaped protrusions 35. The centers of the multiple crosses located outside the circles indicate valley points 38 of second undulation portion 52. Peaks 31 of angled protrusions 35 are located axially most outward on undulation surface 30, and valley points 38 are located axially most inward on undulation surface 30, on the tire inner surface side.

[0031] In this example, when the tire circumferential pitch of the undulating surface 30 is Pr (FIG. 3) and the tire radial pitch of the undulating surface 30 is Pd (FIG. 3), it is preferable that Pd>Pr and Pr / Pd is equal to or greater than 0.2 and less than 1. With this configuration, the tire circumferential pitch Pr is reduced, thereby improving the tire radial rigidity at many positions in the tire circumferential direction and improving handling stability.

[0032] Both ends of the undulating surface 30 in the tire radial direction are connected to the wall surfaces of both ends of the annular recess 37 in the tire radial direction. A height H1 (FIG. 4) from a valley point 38 of the undulating surface 30 to an apex 31 of the angled protrusion 35 is slightly larger than a depth D (FIG. 4) from an opening end 39 of the annular recess 37 to the valley point 38 on the bottom surface. As a result, the vicinity of the apex 31 of each angled protrusion 35 protrudes outward beyond the opening end 39 of the annular recess 37.

[0033] 4, the height H1 of the undulating surface 30 is, for example, 0.3 mm or more and 1.1 mm or less. On the other hand, the depth D of the annular recess 37 is 0.2 mm or more and 1.0 mm or less, and it is preferable that the vicinity of the apex 31 of the angled protrusion 35 protrudes outward from the opening end 39 of the annular recess 37 by 0.1 mm or more. By having the vicinity of the apex 31 of the angled protrusion 35 protrude outward from the opening end 39 of the annular recess 37 in this manner, the presence of the undulating surface 30 can be emphasized from the outside, thereby improving the design of the tire side surface 13.

[0034] 3 and 6, the tire circumferential pitch Pr of the undulating surface 30, which is the distance between the apexes 31 of the angled protrusions 35 in the tire circumferential direction, is 3 mm or more and 80 mm or less. Preferably, the tire circumferential pitch Pr is 20 mm or more and 30 mm or less.

[0035] Furthermore, when the circumferential pitch of the undulation surface 30 is Pr and the height of the undulation surface 30 is H1, the radius of curvature of the curved surfaces of the peaks and valleys of the undulation surface 30 in the circumferential direction of the tire is equal to or greater than (Pr / 2) and equal to or less than ((Pr / H1)+Pr). The radius of curvature of the curved surfaces of the peaks and valleys in the circumferential direction of the tire may be the same or different. For example, the radius of curvature of the curved surfaces of the peaks in the circumferential direction of the tire may be greater than the radius of curvature of the curved surfaces of the valleys. In this case, a wider area of ​​the tire side surface 13 can receive input from the road surface to the tire, thereby increasing rigidity.

[0036] Furthermore, since the undulating surface 30 is formed so as to rise from the bottom surface of the annular recess 37 in the tire axial direction as described above, it becomes easier to equalize the volume of the tire rubber, it becomes easier to form the undulating surface 30, and the weight of the entire tire can be reduced.

[0037] Furthermore, a plurality of curved protrusions 34 are provided on the surface of the undulating surface 30. The plurality of curved protrusions 34 are arranged at a plurality of positions in the tire radial direction and at a plurality of positions in the tire circumferential direction on the undulating surface 30. For example, the plurality of curved protrusions 34 may be arranged at a plurality of positions in the tire radial direction and at a plurality of positions in the tire circumferential direction on the undulating surface 30 at approximately equal intervals.

[0038] The configuration of each curved protrusion 34 will be described with reference to Fig. 6 and Figs. 7 and 8. Fig. 7 is an enlarged perspective view of the curved protrusion 34. Fig. 8 is a view of the curved protrusion 34 as seen from the outside in the height direction Z. Hereinafter, the curved protrusion 34 will be referred to as the protrusion 34.

[0039] 7, each protrusion 34 protrudes in a generally conical shape from the undulating surface 30. As a result, when viewed from the side perpendicular to the height direction Z of the protrusion 34, it has a triangular shape that is convex outward, and its horizontal length decreases toward the tip. The "horizontal direction" is the direction perpendicular to the height direction Z of the protrusion 34.

[0040] As shown in Fig. 8, the shape of the base end of each protrusion 34 when viewed from the outside in the height direction is circular. Here, "circular" means that the length ratio of the vertical and horizontal directions, which are perpendicular to each other, is 0.85 to 1.15. In Fig. 8, the vertical direction is the direction of arrow F, and the horizontal direction is the direction of arrow G. In other words, when the vertical length is LF and the horizontal length is LG, a shape that satisfies 0.85≦LF / LG≦1.15 is defined as "circular."

[0041] In this way, the protrusions 34 are provided on the undulating surface 30, and the contrast between the protrusions and recesses can be utilized to improve the design of the tire 1. Furthermore, when the vehicle is running, air can flow smoothly around the protrusions 34 along the curved shape of the outer periphery of the undulating surface 30, as indicated by arrows A1 and A2 in Figure 8, thereby obtaining the effect of suppressing an increase in air resistance.

[0042] As indicated by the arrow β in FIG. 6 , each protrusion 34 protrudes in a direction perpendicular to the protrusion formation plane at the protrusion formation position on the undulating surface 30. The "protrusion formation plane" is the tangent plane when the protrusion 34 is assumed to be in contact with the undulating surface 30. Because each protrusion 34 protrudes in a direction perpendicular to the protrusion formation plane, the air resistance reduction effect described below can be enhanced. Furthermore, in a portion where two protrusions 34 are arranged close to each other on either side of a valley point 38 of a valley portion of the undulating surface 30, shadows are likely to be generated between the protrusions 34. On the other hand, in a portion where two protrusions 34 are arranged on either side of a vertex 31 of the undulating surface 30, light is likely to be reflected between the protrusions 34. This makes it easier for light and dark contrasts to occur on the undulating surface 30.

[0043] Of the vertical length LF and horizontal length LG of the base end shape of the protrusions 34, the maximum length La, which is the longer length, is 0.15 mm or more and 5.0 mm or less, and it is preferable that the height of the protrusions 34 be 0.8 to 1.5 times this maximum length La, in terms of improving design and suppressing an increase in air resistance. On the other hand, if the maximum length La is less than 0.15 mm, the effect of improving design is reduced. If the maximum length La exceeds 5.0 mm, the effect of suppressing an increase in air resistance is reduced. If the height of the protrusions 34 is less than 0.8 times the maximum length La, the effect of improving design is reduced. If the height of the protrusions 34 exceeds 1.5 times the maximum length La, the effect of suppressing an increase in air resistance is reduced.

[0044] 6, when the arrangement interval between adjacent protrusions 34 is P2 and the height of each protrusion 34 is H2, the protrusion interval height ratio P2 / H2 is equal to or greater than 2 and equal to or less than 6. This makes it possible to reduce the air resistance of the tire 1 while suppressing deterioration in appearance.

[0045] According to the tire 1 described above, the undulating curved surface 30 on the tire side surface 13 increases the tire surface area, thereby suppressing an increase in internal heat generation. Furthermore, the curved surface has no or few edges, suppressing the generation of turbulence, thereby reducing air resistance. Furthermore, wet braking performance, i.e., braking performance on wet roads, can be improved without compromising the tire's wear resistance and handling stability. Specifically, the tire's radial undulations, which are separated in the tire circumferential direction, facilitate movement of the rubber on the tire side surface 13 in the shear direction (the tire's longitudinal direction) while shifting appropriately in parts during wet braking. This allows the rubber to move in the direction of travel with appropriate partial shifting. This improves wet braking performance without compromising wear resistance. Furthermore, the undulating curved surface 30 allows the rubber on the tire side surface 13 at the bottom of the tire to easily deform vertically in response to changes in the road surface, thereby increasing the contact area. This also improves wet braking performance. Furthermore, the circumferential undulation of the tire allows the rubber on the tire side surface 13 to adequately absorb vertical movement, thereby maintaining steering stability. Also, the multiple protrusions 34 make it easier to create contrast on the tire side surface.

[0046] FIG. 9 is a schematic diagram showing that, in an embodiment, after an airflow collides with a protrusion 34, turbulence causes the airflow to reattach to another downstream protrusion 34, making the separation point more likely to shift downstream. In this embodiment, the protrusion-to-height ratio P2 / H2 is between 2 and 6, so that the airflow that collides with a protrusion 34 on the undulating surface 30 becomes turbulent and heads downstream. This turbulent flow then collides again with another downstream protrusion 34, and so on. This makes it easier for the separation point of the airflow on the undulating surface 30 to shift downstream. Therefore, as described below, the width of the wake region, which is formed by the portion sandwiched on both sides by the separated airflow from the separation position on the undulating surface 30 and creates a negative pressure, can be reduced on the downstream side of the airflow in the tire. This reduces the pressure resistance caused by the formation of the protrusions 34, thereby suppressing an increase in air resistance.

[0047] FIG. 10 is a schematic diagram showing how, in another embodiment, the surface of an undulating curved surface is similar to a smooth surface in preventing turbulence. When the projection-to-height ratio P2 / H2 is less than 2, as shown in FIG. 10, the density of the projections 34a per unit area of ​​the undulating curved surface increases. This results in the undulating curved surface being similar to a smooth surface in relation to the airflow indicated by the arrow δ, making it less likely to generate turbulence in the airflow. This makes it less likely that the separation point of the airflow on the undulating curved surface will shift downstream. This reduces the negative pressure reduction effect, thereby reducing the effect of suppressing increases in air resistance.

[0048] On the other hand, if the projection spacing height ratio P2 / H2 exceeds 6, the number of projections 34 formed on the undulating surface decreases, reducing the effect of reducing negative pressure. In this case as well, the effect of suppressing an increase in air resistance decreases.

[0049] The effects of the embodiment will be described in more detail using Figures 11 and 12. Figure 11 is a schematic diagram showing, using a cylinder Sa as a simulation, how a separated airflow creates a wake region 40 downstream of the airflow from the tire side surface 13 in another example configuration in which the projection interval height ratio P2 / H2 is less than 2. In Figure 11, many turbulent flows are formed inside the wake region 40. In Figures 11 and 12, the tire is simulated by the cylinders Sa and S.

[0050] In another example shown in FIG. 11 , the protrusion spacing-height ratio P2 / H2 is less than 2, so the undulating curved surface does not generate turbulence, just like a smooth surface. In this case, consider the case where an airflow, indicated by a broken line, collides with the surface of a cylinder Sa, which serves as a tire side surface 13, as the tire rotates during vehicle travel. In this case, a positive pressure is generated on the upstream side of the cylinder Sa in the airflow, pushing the cylinder Sa downstream. Then, as the airflow flows from the upstream side of the cylinder Sa to the downstream side along the surface of the cylinder Sa, the airflow separates from the surface of the cylinder Sa at positions C1 and C2 in FIG. 11 . A wake region 40, where negative pressure exists, is formed in the area sandwiched between the separated airflows from the separation positions of the cylinder Sa. In the case of FIG. 11 , the width (vertical length in FIG. 11 ) of this wake region 40 is large, so the negative pressure reduction effect is small. For this reason, if the projection interval height ratio P2 / H2 is less than 2, the effect of suppressing an increase in pressure resistance in the tire is low, and therefore the effect of suppressing an increase in air resistance is also small.

[0051] 12 is a schematic diagram illustrating, in an embodiment, a cylinder S simulating that the width of a wake region 40 caused by a separated air flow narrows downstream of the air flow from the tire side surface 13, thereby enhancing the negative pressure reduction effect. In FIG. 12, the formation of multiple protrusions 34 on the tire side surface 13 on both sides in the tire axial direction is simulated by small protrusions formed on the surface of the cylinder S.

[0052] As shown in FIG. 12 , in the embodiment, the protrusion spacing-height ratio P2 / H2 is equal to or greater than 2 and equal to or less than 6. Therefore, for the reasons explained in FIG. 9 , the separation point of the airflow from the tire side surface 13 is likely to shift to downstream positions C3 and C4. This makes it possible to reduce the width of a wake region 40 that is formed on the downstream side of the cylinder S simulating a tire, in a portion sandwiched on both sides by the separated airflow from the separation point on the surface of the cylinder S and that experiences negative pressure. FIG. 12 simulates the formation of multiple protrusions 34 on the tire side surface 13 on both axial sides of the tire. However, even if multiple protrusions 34 are formed only on the tire side surface 13 on the vehicle outer side, as in the embodiment, the width of the wake region 40 is reduced. As a result, in the embodiment, the effect of suppressing an increase in pressure resistance in the tire is enhanced, and an increase in air resistance can be suppressed.

[0053] In addition, in the embodiment, the undulating surface 30 may be configured to be formed on the tire side surface 13 within a range in the tire radial direction Y (the range indicated by the arrow η in FIG. 1 ) of 25% or more and 65% or less when the tire radial position of the rim line 20 is set to 0 and the tire cross-sectional height Ht is set to 100.

[0054] According to this configuration, the undulating surface 30 can be provided in a range from the vicinity of the outer end in the tire axial direction (P in FIG. 1) of the tire side surface 13 corresponding to the maximum tire width, that is, the outer portion in the tire radial direction Y, where the air flow is likely to hit, to the outer peripheral portion of the tire that is easily noticeable and has a great effect in improving the design.

[0055] Fig. 13 is a cross-sectional view showing a tire molding mold of an embodiment. The tire 1 of this embodiment is formed using a tire molding mold 70. Hereinafter, the tire molding mold 70 will be referred to as mold 70. The mold 70 is a mold that molds the tire 1 shown in Figs. 1 to 9 above. The mold 70 makes it possible to achieve a balance between suppressing an increase in internal heat generation, reducing air resistance, and improving braking performance and handling stability on wet roads, and also to realize a tire 1 that is likely to produce contrast on the tire side surface 13.

[0056] Hereinafter, each member will be described in accordance with the tire axial direction X and tire radial direction Y of the tire 1 molded by the mold 70.

[0057] The mold 70 has a tread mold 71 for molding the surface of the tread of the tire 1, and a pair of side molds 72 for molding the surfaces of the sidewalls.

[0058] The tread mold 71 has a body 74 having a tread molding surface 73 and a protrusion 75 protruding from the tread molding surface 73 .

[0059] The main body 74 is made of a metal material, for example, an aluminum alloy. As the aluminum alloy, for example, AC4 series, AC7 series, etc. are preferably used. The protrusions 75 are portions that form circumferential grooves in the tire 1. The protrusions 75 are made of the same material as the metal material that makes up the main body 74.

[0060] The side mold 72 has a main body 76 with side molding surfaces 77a, 77b, and the side molding surface 77a, which is used to form the tire side surface on the outer side of the vehicle, has an annular protrusion 78 that protrudes outward from the side molding surface 77a. The main body 76 is made of the same metal material as the main body 74. The annular protrusion 78 is a part that forms, in the tire 1, an annular recess 37 (FIGS. 2 to 4) having an undulating curved surface 30 on the inside.

[0061] The tread mold 71 has a fan shape in a plan view, formed by dividing an annular body into multiple parts in the circumferential direction. The multiple divided tread molds 71 ​​form a continuous annular body with an inner diameter corresponding to the outer diameter of the tire 1 to be molded when in a clamped state, as described below. The upper side mold 72 is annular and fixed to the lower surface of an upper plate (not shown) constituting the vulcanization molding machine, and moves up and down as a first lifting member (not shown) moves up and down. The lower side mold 72 is annular and fixed to the floor surface and to the lower surface of a lower plate (not shown) constituting the vulcanization molding machine. The vulcanization molding machine raises and lowers multiple segments (not shown), one for each tread mold 71, outside the multiple divided tread molds 71, using a first lifting member. Simultaneously with the raising and lowering of the first lifting member, the vulcanization molding machine slides the inclined surfaces of the outer peripheral surfaces of the multiple segments up and down on an inclined cylindrical surface provided at the lower end of a second lifting member (not shown) that moves up and down independently of the first lifting member. As a result, the vulcanization molding machine reciprocates the multiple segments in the radial direction relative to the central axis of the annularly continuous tread mold 71. As a result, the vulcanization molding machine switches the mold 70 between a mold clamped state and a mold open state.

[0062] In the mold 70 configured in this manner, a green tire is placed on the lower tread mold 71 with the tire axial direction aligned vertically when the mold is open. An inflatable bladder is then placed inside the green tire, and air is supplied to the bladder to inflate it. Then, with the inner surface of the green tire held by the outer surface of the bladder, the first lifting member and the second lifting member are raised and lowered to close the mold 70. The rubber of the green tire is pressed against the tread molding surface 73 and side molding surfaces 77a, 77b by the pressure from the mold 70, and a heat exchange medium adjusted to a predetermined temperature is constantly flowing between the member fixing the upper plate and the member fixing the lower plate. This vulcanizes the rubber of the green tire, completing a tire 1 with a predetermined shape.

[0063] In this embodiment, an annular protrusion 78 is formed on a side molding surface 77a for forming the tire side surface 13 on the vehicle outer side to mold an annular recess 37 having an undulating surface 30 on the inside. A peak 78a at the top of the annular protrusion 78 corresponds to the valley point 38 of the valley of the annular recess 37. Furthermore, a mold-side curved surface 80 is formed on the side surface of the annular protrusion 78 so as to undulate in the circumferential and radial directions in correspondence with the undulating surface 30. A plurality of inner-curved surface recesses (not shown) are formed on the mold-side curved surface 80 in correspondence with the plurality of protrusions 34 of the undulating surface 30.

[0064] The multiple recesses in the curved surface of the mold can be formed by drilling holes in the mold-side curved surface 80 of the mold. For example, NC machining using a cutting tool such as an end mill, laser machining, or electric discharge machining can be used for the drilling.

[0065] The tire obtained using the above tire 1 and mold 70 achieves a balance between suppressing an increase in internal heat generation, reducing air resistance, and improving braking performance and steering stability on wet roads, and also provides a tire 1 that is likely to produce contrast on the tire side surface 13.

[0066] In the above embodiment, the shape of the protrusion 34 when viewed from the side perpendicular to the height direction is triangular, but in the present invention, the curved protrusion is not limited to this shape. Figures 14 to 17 show four examples of curved protrusions in tires according to other embodiments.

[0067] First, the protrusion 34b of the first example of the modification shown in Fig. 143 has a shape seen from the side that is a truncated cone shape having inclined sides 32 on both lateral sides. The shape of the protrusion 34b seen from the outside in the height direction is circular, similar to the case of the protrusion 34 shown in Fig. 8.

[0068] The protrusion 34c of the second example shown in Fig. 15 has a cylindrical shape that is substantially rectangular when viewed from the side. The shape of the protrusion 34c when viewed from the outside in the height direction is circular, similar to the protrusion 34 shown in Fig. 8.

[0069] The protrusion 34d of the third example shown in Fig. 16 has a substantially semicircular hemispherical shape when viewed from the side. The shape of the protrusion 34d when viewed from the outside in the height direction is circular, similar to the protrusion 34 shown in Fig. 8.

[0070] 17 shows a fourth example of protrusion 34e, which has a mountain-like shape when viewed from the side with inclined sides 33a on both sides in the horizontal direction, and a shape in which an arc-shaped portion is at the top end and curved portion 33b that is convex outward is connected. The shape of protrusion 34e when viewed from the outside in the height direction is circular, similar to protrusion 34 shown in FIG.

[0071] Fig. 18 is a perspective view showing a protrusion 34f in a tire according to another example of the embodiment. Fig. 19 is a view seen in the direction of arrow C in Fig. 18. Fig. 20 is a cross-sectional view taken along line DD in Fig. 19. Fig. 21 is a cross-sectional view taken along line EE in Fig. 19.

[0072] The protrusions 34f in the tire of this example have a shape that can create a sense of brightness based on strong contrast on the tire side surface when viewed from a direction perpendicular to the undulating surface 30. Specifically, as will be described later, the protrusions 34f in this example are polygonal shapes that have two first surfaces 83 that stand upright from the undulating surface 30 at an angle in the range of ±15% based on a surface that stands upright at 90 degrees to the undulating surface 30, and two second surfaces 84 that are connected to the first surfaces 83 at their peaks and rise so as to be inclined at an angle greater than 90 degrees + 15% relative to the undulating surface 30.

[0073] The two first surfaces 83 are identically shaped rectangles and are connected to each other in a V-shape. The two second surfaces 84 are connected to each first surface 83 and are connected to each other in a V-shape, and are symmetrical with respect to a connecting line 85 between the two second surfaces 84. The protrusion 34f has two triangular third surfaces 88 connected to the first surface 83 and the second surface 84 at both ends in the longitudinal direction along the ridge line 87 of the V-shape. As shown in FIG. 19, the shape of each second surface 84 is rhombic when viewed in a direction perpendicular to the position of the protrusion 34f on the undulating surface 30. Furthermore, as shown in FIG. 21, the position of each second surface 84 becomes higher as it approaches the ridge line 87 of the V-shape (FIGS. 18 and 19).

[0074] 20, each first surface 83 of each protrusion 34f stands upright from the undulating surface 30 at an angle α1 within a range of ±15% with respect to a surface S1 that stands upright at 90 degrees to the undulating surface 30. Furthermore, each second surface 84 of each protrusion 34f is connected to the first surface 83 by a ridge line 87 and stands up so as to be inclined at an angle α2 that is greater than 90 degrees + 15% relative to the undulating surface 30.

[0075] 20 is erected from the undulating surface 30 at the same angle α as the surface S1 that stands upright at 90 degrees relative to the undulating surface 30, but it may also be erected from the undulating surface 30 at an angle greater than 90 degrees or less than 90 degrees within a range of 90 degrees ±15%. Also, each second surface 84 of each protrusion 34f may be erected at an angle greater than 90 degrees +30%, or more preferably, at an angle greater than 90 degrees +50%, relative to the undulating surface 30.

[0076] As a result, the second surface 84 forms a light-reflecting surface on the undulating surface 30, and the first surface 83 creates shadow areas such as black lines, thereby providing a strong contrast to the tire side surface. As a result, an excellent sense of brilliance can be achieved on the tire side surface by utilizing the reflection of light, resulting in a tire with excellent design.

[0077] Here, unlike the embodiment, consider a case where each first surface 83 of each protrusion 34f stands upright from the undulation surface 30 at an angle exceeding +15% with respect to a surface S1 that is perpendicular to the undulation surface 30 at an angle of 90 degrees (for example, as shown by the dashed dotted line α3 in FIG. 20 , the angle formed by the surface S1 with the undulation surface 30 is greater than θ1, which is an angle of +15% with respect to the 90-degree surface S1). In this case, the increase rate of brightness due to the first surface 83 exceeds 15%, making it difficult to create a contrast between light and dark on the tire side surface.

[0078] Also, unlike the embodiment, consider a case in which each first surface 83 of each protrusion 34f stands upright from the undulating surface 30 at an angle of less than -15% with respect to a surface that is perpendicular to the undulating surface 30 and at an angle of 90 degrees (for example, so that the angle formed with the undulating surface 30 is smaller than θ2, which is an angle of -15% with respect to the 90-degree surface S1 as shown by the dashed-dotted line α4 in FIG. 20). In this case, the so-called under-angle becomes larger and the difference in brightness on the tire side surface becomes greater, but there is a possibility that the rubber will tear when the molded tire is removed from the mold during tire molding, reducing moldability.

[0079] As in the embodiment of Figures 18 to 21, each first surface 83 of each protrusion 34f is erected from the undulating surface 30 at an angle within a range of ±15% based on a surface S1 that stands upright at 90 degrees to the undulating surface 30, thereby preventing such inconveniences, making it easier to create a difference in brightness on the tire side surface, and maintaining good tire moldability.

[0080] 18 to 21, the protrusion 34f provided on the undulating surface 30 has been described as a six-sided polygon including two first surfaces 83 and two second surfaces 84. However, the protrusion may have any polygonal shape having at least one first surface and one second surface. For example, the protrusion may have a single first surface extending from the undulating surface at an angle within a range of ±15% of a surface that is perpendicular to the undulating surface at 90 degrees, and a single second surface connected to the first surface at its apex and inclined at an angle greater than 90 degrees + 15% relative to the undulating surface, with four sides including third surfaces at both ends. In this example, the other configurations and functions are the same as those in FIGS. 1 to 9.

[0081] 22 is a view of a protrusion 34g of a tire according to another example of the embodiment, viewed from the outside in the height direction. In this example, the shape of the protrusion 34g when viewed from the outside in the height direction is triangular, and the protrusion 34g may be a triangular pyramid or triangular prism. Furthermore, in the shape of the base end of the protrusion 34g when viewed from the outside in the height direction, the ratio (LF1 / LG1) of the longitudinal length LF1 to the lateral length LG1, which are perpendicular to each other, may be 0.85 to 1.15. Furthermore, the height of each protrusion 34g may be 0.8 to 1.5 times the longer of the longitudinal length LF1 and the lateral length LG1.

[0082] 23 is a view of a protrusion 34h in a tire according to another example of the embodiment, viewed from the outside in the height direction. In this example, the shape of the protrusion 34h when viewed from the outside in the height direction is a parallelogram, and the protrusion 34h may be a square pyramid or a square prism. Furthermore, in the shape of the base end of the protrusion 34h when viewed from the outside in the height direction, the ratio (LF2 / LG2) of the longitudinal length LF2 to the lateral length LG2, which are perpendicular to each other, may be 0.85 to 1.15. Furthermore, the height of each protrusion 34h may be 0.8 to 1.5 times the longer of the longitudinal length LF2 and the lateral length LG2.

[0083] 24 is a view of a protrusion 34i in a tire according to another example of the embodiment, viewed from the outside in the height direction. In this example, the shape of the protrusion 34i when viewed from the outside in the height direction is a regular pentagon, and the protrusion 34i may be a pentagonal pyramid or a pentagonal prism. Furthermore, in the shape of the base end of the protrusion 34i when viewed from the outside in the height direction, the ratio (LF3 / LG3) of the longitudinal length LF3 to the lateral length LG3, which are perpendicular to each other, may be 0.85 to 1.15. Furthermore, the height of each protrusion 34i may be 0.8 to 1.5 times the longer of the longitudinal length LF3 and the lateral length LG3.

[0084] Although not shown in the drawings, another example of the protrusion may be a hexagonal pyramid or hexagonal column that has a regular hexagonal shape when viewed from the outside in the height direction.

[0085] Figure 25 is a view corresponding to Figure 6 of a tire according to another example of the embodiment. In the configuration of this example, unlike the configurations of Figures 1 to 9, multiple protrusions 34 protrude parallel to each other from the undulating surface 30 and face outward in a direction perpendicular to the sidewall reference plane. According to the configuration of this example, when the spacing between the multiple protrusions 34 is reduced, the light absorption effect can be improved, and the spaces between the protrusions 34 can be made dark, making it easier to create contrast with other bright parts.

[0086] Fig. 26 is a schematic diagram showing the light absorption effect produced by the configuration of Fig. 25. In the configuration of Fig. 25, when the spacing between the multiple protrusions 34 is small as shown in Fig. 26, when light enters between the protrusions from the outside, it is more likely to penetrate deeper between the protrusions 34 while being reflected by the side surfaces of the protrusions 34, as shown by arrows β1, β2, and β3. As a result, the configuration of this example has a high light absorption effect. In this example, the other configurations and functions are the same as those of the configurations of Figs. 1 to 9.

[0087] 27 is a schematic diagram showing the positions of peaks 31 and valleys 38 in a portion of the undulation surface 30a in the tire circumferential direction in a tire according to another embodiment. In the configuration of this example, unlike the configurations of FIGS. 1 to 8, the phases of the peaks 31 of multiple first undulation portions 51 undulating in the tire circumferential direction at multiple positions in the tire radial direction in the undulation surface 30a are shifted by half a pitch between two first undulation portions 51 adjacent in the tire radial direction. Furthermore, between two first undulation portions 51 adjacent in the tire radial direction, a second undulation portion 52a extends in the tire circumferential direction while changing into a wave-like shape on both sides in the tire radial direction. The dashed lines, circles, and crosses in FIG. 27 have the same meanings as those in FIG. 5. In the configuration of this example, unlike the configuration shown in Figure 5, the positions of the angled protrusions 35 of the first undulation portions 51 adjacent in the tire radial direction are offset in the tire circumferential direction, so that the angled protrusions 35 can be arranged more densely when viewed from the tire axially outer side than in the configuration of Figure 5. This makes it possible to increase the tire radial rigidity at more positions in the tire circumferential direction on the tire side surface. This therefore makes it possible to further improve steering stability on dry roads. In this example, the other configurations and functions are the same as those of the configurations of Figures 1 to 9.

[0088] In the above-described embodiments, the tire side surface 13 is provided with an annular portion 100 including the undulating surfaces 30, 30a, continuously around the entire circumference in the tire circumferential direction. However, in the above-described embodiments, instead of the annular portion 100, the tire side surface may be provided with an arc-shaped portion that is provided only in a portion in the tire circumferential direction or in multiple locations in the tire circumferential direction and has an arc-shaped recessed portion with an arc-shaped undulating surface formed inside. The arc-shaped portion has an undulating surface that undulates in the tire radial and circumferential directions so as to have multiple chevron-shaped protrusions in the tire radial and circumferential directions inside the arc-shaped recessed portion along the tire circumferential direction. The arc-shaped portion is preferably formed in a band-like area extending in the tire circumferential direction that covers 25% or more of the entire circumference in the tire circumferential direction. Alternatively, the undulating surface may be formed in four or more locations in the tire circumferential direction, for example. Furthermore, when the undulating surfaces are arranged at multiple positions in the tire circumferential direction, the total circumferential length of each undulating surface is preferably 50% or more of the total circumferential length of the tire at the radial position of the undulating surface. Regarding the range of the undulating surface in the tire circumferential direction, the proportion of the total circumferential length of the portion where the undulating surface is arranged to the entire circumference of the sidewall is preferably 50% or more, more preferably 80% or more, and most preferably the entire circumference (100%).

[0089] Furthermore, instead of the annular protrusion 78 formed on the side molding surface 77a of the mold 70 shown in Figure 13, multiple arc-shaped portions having an arc-shaped mold side curved surface for molding an arc-shaped undulating surface may be formed.

[0090] Furthermore, in the above-described embodiments, the undulating surfaces 30, 30a are formed inside the annular or arc-shaped recess formed in the tire side surface 13. However, an undulating surface may be formed that protrudes axially outward from the sidewall reference plane of the tire side surface, and that undulates in the tire radial and circumferential directions so as to have multiple angle-shaped protrusions in the tire radial and circumferential directions.

[0091] In each of the above embodiments, although not shown in the drawings, markings such as letters, symbols, etc. may be provided on the undulating surface. In each of the above embodiments, when the undulating surface is provided at a portion of the sidewall in the circumferential direction or at multiple positions in the circumferential direction, markings such as letters, symbols, etc. may be provided on a curved surface or smooth surface that is located at the same position in the tire radial direction as the undulating surface and does not have the undulating surface.

[0092] The present disclosure is further illustrated by the following embodiments. Configuration 1: The tire side surface is located radially inward of the tread contact edge and radially outward of the rim line, and is provided with an undulating curved surface that undulates radially and circumferentially to have multiple mountain-shaped protrusions in the radial and circumferential directions. A plurality of curved surface protrusions are provided on the surface of the undulating curved surface. Pneumatic tires. Configuration 2: When each of the plurality of curved protrusions is viewed from the outside in the height direction, the shape of the base end is a circle with a length ratio of 0.85 to 1.15 in the vertical and horizontal directions, which are orthogonal to each other. 10. The pneumatic tire according to claim 1. Configuration 3: The height of each of the plurality of curved protrusions is 0.8 to 1.5 times the longer of its length in the vertical direction or its length in the horizontal direction. 3. The pneumatic tire according to claim 2. Configuration 4: When the arrangement interval between adjacent curved projections is P2 and the height of each of the plurality of curved projections is H2, P2 / H2 is 2 or more and 6 or less. 4. The pneumatic tire according to claim 3. Configuration 5: The undulating curved surface is provided continuously around the entire circumference in the tire circumferential direction. 5. The pneumatic tire of any one of configurations 1 to 4. Configuration 6: A recessed portion recessed from the sidewall reference plane toward the tire inner surface is formed on the tire side surface, and the undulating surface is formed so as to rise from the bottom surface of the recessed portion in the tire axial direction. 6. The pneumatic tire of any one of configurations 1 to 5. Configuration 7: The undulating surface changes periodically in the tire circumferential direction and the tire radial direction, The pitch of the undulating surface in the tire circumferential direction is 3 mm or more and 80 mm or less, The height of the undulating curved surface is 0.3 mm or more and 1.1 mm or less. 7. The pneumatic tire of any one of claims 1 to 6. Configuration 8: When the pitch of the undulating surface in the tire circumferential direction is Pr and the height of the undulating surface is H1, the radius of curvature of the curved surface of the peaks and valleys in the tire circumferential direction of the undulating surface is (Pr / 2) or more and ((Pr / H1)+Pr) or less. 8. The pneumatic tire according to claim 7. Configuration 9: When the pitch of the undulating surface in the tire circumferential direction is Pr and the pitch of the undulating surface in the tire radial direction is Pd, Pr / Pd is 0.2 or more and less than 1. 8. The pneumatic tire according to claim 7. Configuration 10: The undulating surface is formed on the tire side surface within a tire radial range of 25% to 65% when the tire radial position of the rim line or the tire axially outer end of the rim protector is set to 0 and the tire cross-sectional height is set to 100. 10. The pneumatic tire of any one of Configurations 1 to 9. Configuration 11: A pneumatic tire mold for molding the pneumatic tire according to any one of Configurations 1 to 10, The molding surface has a mold-side curved surface corresponding to the undulating curved surface, and a plurality of curved surface recesses corresponding to the curved surface protrusions are formed on the mold-side curved surface. Mold for molding pneumatic tires. [Explanation of symbols]

[0093] 1 pneumatic tire (tire), 10 tread, 11a, 11b blocks, 11c circumferential groove, 12 sidewall, 13 tire side surface, 14 sidewall reference surface, 15 bead, 18 rim strip, 19 rim protector, 20 rim line, 30, 30a undulating surface, 31 vertex, 32 inclined edge, 33a inclined edge, 33b curved portion, 34, 34a, 34b, 34c, 34d, 34e, 34f, 34g, 34i curved surface protrusion (protrusion), 35 angled protrusion, 37 annular recess, 38 valley point, 39 open end, 40 wake region, 51 first undulating portion, 52, 52a second undulating portion, 70 tire molding mold, 71 tread mold, 72 side mold, 73 tread molding surface, 74 Main body, 75 protrusion, 76 main body, 77a, 77b side molding surface, 78 annular protrusion, 78a vertex, 80 mold side curved surface, 83 first surface, 84 second surface, 85 connecting line, 87 ridge line, 88 third surface, 100 annular portion, T ground end.

Claims

1. The tire side surface is provided on the tire radially inward of the ground contact edge of the tread and on the tire radially outward of the rim line, which is the tire axially outer surface, and includes an undulating curved surface that undulates in the tire radial and circumferential directions so as to have a plurality of mountain-shaped protrusions in the tire radial and circumferential directions, A plurality of curved surface protrusions are provided on the surface of the undulating curved surface. Pneumatic tires.

2. a base end of each of the plurality of curved projections when viewed from the outside in the height direction has a circular shape with a length ratio between vertical and horizontal directions that are orthogonal to each other of 0.85 to 1.15; The pneumatic tire according to claim 1 .

3. The height of each of the plurality of curved protrusions is 0.8 to 1.5 times the longer of the vertical length and the horizontal length. The pneumatic tire according to claim 2.

4. When the arrangement interval between adjacent curved protrusions is P2 and the height of each of the plurality of curved protrusions is H2, P2 / H2 is equal to or greater than 2 and equal to or less than 6. The pneumatic tire according to claim 3.

5. The undulating surface is provided continuously around the entire circumference in the tire circumferential direction. The pneumatic tire according to claim 1 .

6. a recess formed in the tire side surface from a sidewall reference plane toward the tire inner surface, and the undulating surface is formed so as to rise from the bottom surface of the recess in the tire axial direction; The pneumatic tire according to claim 1 .

7. the undulating surface changes periodically in the tire circumferential direction and the tire radial direction, The pitch of the undulating surface in the tire circumferential direction is 3 mm or more and 80 mm or less, The height of the undulating surface is 0.3 mm or more and 1.1 mm or less. The pneumatic tire according to claim 1 .

8. When the pitch of the undulating surface in the tire circumferential direction is Pr and the height of the undulating surface is H1, the radius of curvature of the curved surface of the peaks and valleys in the tire circumferential direction of the undulating surface is (Pr / 2) or more and ((Pr / H1)+Pr) or less. The pneumatic tire according to claim 7.

9. When the pitch of the undulating surface in the tire circumferential direction is Pr and the pitch of the undulating surface in the tire radial direction is Pd, Pr / Pd is 0.2 or more and less than 1. The pneumatic tire according to claim 7.

10. The undulating surface is formed on the tire side surface within a tire radial direction range of 25% to 65% when the tire radial direction position of the rim line or the tire axial outer end of the rim protector is set to 0 and the tire cross-sectional height is set to 100. The pneumatic tire according to claim 1 .

11. A pneumatic tire mold for molding the pneumatic tire according to any one of claims 1 to 10, The molding surface has a mold-side curved surface corresponding to the undulating curved surface, and a plurality of curved surface recesses corresponding to the curved surface protrusions are formed on the mold-side curved surface. Mold for molding pneumatic tires.

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