pneumatic tires

Abstract

pneumatic tire (1) comprising a plurality of protrusion sections (9) which extend along a tire sidewall (Sa) of a tire sidewall section (S), intersect a tire circumferential direction or a tire radial direction in the longitudinal direction and are provided at intervals in the circumferential direction of the tire, each of the plurality of protrusion sections (9) having an outer contour comprising a plurality of main outer contour sections (9P1) with different curvatures and a connecting section (9P2) connecting the main outer contour sections (9P1), the outer contour projecting from the tire sidewall in a longitudinal section, wherein in the main outer contour sections (9P1) with the connecting section (9P2) in between at least one of the main outer contour sections (9P1) forms a circle of curvature in the longitudinal direction, the center of which is located closer to the outside of the tire than to the tire sidewall (Sa), the circle of curvature being recessed towards the inside of the tire.

Description

Technical field

[0001] The present invention relates to a pneumatic tire. State of the art

[0002] In the prior art, for example, patent document 1 discloses a pneumatic tire in which, when mounted on a vehicle, a large number of protruding sections (projecting sections) extending in the tire's radial direction are provided at predetermined intervals in the tire's circumferential direction on a tire sidewall section (outer tire surface) on the inside in the width direction of the vehicle. With this pneumatic tire, an airflow around the tire can be promoted during driving, thus effectively reducing air resistance under high-speed driving conditions.

[0003] Furthermore, patent document 2, for example, describes a vehicle tire with a sidewall featuring curved projections. Patent document 2 describes how an airflow against the sidewall does not flow naturally along the sidewall but instead moves within a wheel well of the vehicle, generating downforce that pushes the upper edge of the tire's tread downwards. Note that the resulting downforce reduces lift, the force that lifts the vehicle. Patent documents 3 and 4 each describe a pneumatic tire that can suppress crack growth. Patent document 5 describes a pneumatic tire that can reduce lift and drag while maintaining good uniformity. Patent document 6 describes a pneumatic tire that, among other things, offers improved ride comfort. List of literature on patent literature Patent document 1: JP 2010- 260 378 A Patent document 2: JP 2013- 18 474 A Patent document 3: WO 2017 / 056 976 A1 Patent document 4: DE 11 2016 004 488 T5 Patent document 5: DE 11 2016 002 173 T5 Patent document 6: US 2012 / 0 073 719 A1 Brief description of the invention: Technical problem

[0004] As described in patent document 1, it is known that air resistance during driving is reduced by providing the protrusion sections on the tire sidewall section, but there is a need for a further reduction of air resistance with improved vehicle performance.

[0005] In view of the foregoing, it is an object of the present invention to provide a pneumatic tire that can ensure a further reduction in air resistance. Solution to the problem

[0006] To solve the problems described above and to fulfill the objective, a pneumatic tire according to the present invention includes a plurality of protrusion sections extending along a tire sidewall of a tire sidewall section, intersecting a tire circumferential direction or a tire radial direction longitudinally and provided at intervals in the tire circumferential direction, and each of the protrusion sections has an outer contour that includes a plurality of main outer contours with different curvatures, and a connecting section that connects the main outer contour sections, wherein the outer contour projects from the tire sidewall in a longitudinal section, wherein in the main outer contour sections with the connecting section between them, at least one of the main outer contour sections forms a circle of curvature in the longitudinal direction.the center of which is located closer to the outside of the tire than to the tire sidewall, wherein the circle of curvature is recessed towards the inside of the tire. In a pneumatic tire according to one aspect of the present invention, the outer contour is preferably formed along a crest line of the protrusion section.

[0007] In a pneumatic tire according to one aspect of the present invention, the outer contour is preferably formed along a surface of the protrusion section.

[0008] Furthermore, in a pneumatic tire according to one aspect of the present invention, the outer contour preferably comprises the majority of main outer contour sections and the connecting section, which are formed in a region that excludes a region from each of the ends in the longitudinal direction up to (L×0.05) with respect to a dimension L of the protrusion section in the longitudinal direction.

[0009] Furthermore, in a pneumatic tire according to one aspect of the present invention, the outer contour preferably comprises the majority of main outer contour sections formed in a range from (L×0.7) to (L×0.9) and the connecting section formed in a range from (L×0) to (L×0.3) with respect to the dimension L of the protrusion section in the longitudinal direction.

[0010] Furthermore, in a pneumatic tire according to one aspect of the present invention, when the pneumatic tire is mounted on a normal rim, inflated to a normal internal pressure, in contact with a road surface which is a horizontal surface with a normal load, and is rolled on the road surface, in a case where a relative velocity U between the tire sidewall section and the road surface is expressed by U [m / s] = V × r / Q and a Reynolds number Re is expressed by Re = U × Q / v, where V is a primary flow velocity [m / s] opposite to a rolling direction of the pneumatic tire, r is a distance [m] from the road surface in the direction of the axis of rotation, Q is a distance [m] from the road surface to the axis of rotation, and v is a kinematic viscosity of the air [m 2 / s] and the primary flow velocity V [m / s] is 27.8, the protrusion section is preferably provided at a position where the Reynolds number is Re 2000 < Re < 4 × 10 5 fulfilled.

[0011] Furthermore, in a pneumatic tire according to one aspect of the present invention, the total volume Vo of the protrusion sections preferably covers a range of 1000 [mm²]. 3 ] ≤ Vo ≤ 50000 [mm 3 ] in the range of the Reynolds number Re.

[0012] In a pneumatic tire according to one aspect of the present invention, each of the protrusion sections preferably has a highest position of a projection height from the tire sidewall of 2 mm or higher and 10 mm or lower.

[0013] In a pneumatic tire according to one aspect of the present invention, the variation in the protrusion height of each of the protrusion sections per 1 degree in the tire circumferential direction is preferably 1 mm / degree or less.

[0014] In a pneumatic tire according to one aspect of the present invention, the variation in the mass of each of the protrusion sections per 1 degree in the tire circumferential direction is preferably 0.1 g / degree or less.

[0015] In a pneumatic tire according to one aspect of the present invention, the plurality of protrusion sections are preferably arranged at uneven intervals in the circumferential direction of the tire.

[0016] Furthermore, in a pneumatic tire according to one aspect of the present invention, a vehicle inside / outside orientation is preferably characterized when mounting the pneumatic tire on the vehicle, and the majority of protrusion sections are formed on at least the tire side section which corresponds to the vehicle outside. Advantageous effects of the invention

[0017] Since the outer contour of the protrusion section includes multiple main outer contour sections with varying curvatures and a connecting section linking them, the airflows along these sections collide at the point of the connecting section. This collision generates a vortex, which in turn promotes the creation of a turbulent boundary layer through the protrusion sections. Consequently, the airflow around the tire is further enhanced, and the propagation of air away from the vehicle on the outside of the wheel well is further suppressed, thus improving the reduction of drag generated by the vehicle. Brief description of the drawings Fig. Figure 1 is a meridian cross-sectional view of a pneumatic tire according to an embodiment of the present invention. Fig. Figure 2 is a side view of a pneumatic tire according to an embodiment of the present invention. Fig. Figure 3 is a longitudinal sectional view of a protrusion section not according to the invention. Fig. Figure 4 is a longitudinal sectional view of a protrusion section of an example according to the invention. Fig. Figure 5 is a longitudinal sectional view of a protrusion section of a non-inventive example. Fig. Figure 6 is a longitudinal sectional view of a protrusion section of a non-inventive example. Fig. Figure 7 is a longitudinal sectional view of a protrusion section of a non-inventive example. Fig. Figure 8 is a longitudinal section view of a protrusion section of a non-inventive example. Fig. Figure 9 is a cross-sectional view of a protrusion section. Fig. Figure 10 is a cross-sectional view of a protrusion section from another example. Fig. Figure 11 is a cross-sectional view of a protrusion section from another example. Fig. Figure 12 is a cross-sectional view of a protrusion section from another example. Fig. Figure 13 is a cross-sectional view of a protrusion section from another example. Fig. Figure 14 is a cross-sectional view of a protrusion section from another example. Fig. Figure 15 is an explanatory diagram of the operating principle of a state-of-the-art pneumatic tire. Fig. Figure 16 is an explanatory diagram of the operating principle of a state-of-the-art pneumatic tire. Fig. Figure 17 is an explanatory diagram of the mode of operation of a pneumatic tire according to an embodiment of the present invention. Fig. Figure 18 is an explanatory diagram of the mode of operation of a pneumatic tire according to an embodiment of the present invention. Fig. 19 is an explanatory diagram of the mode of operation of a non-inventive pneumatic tire Fig. Figure 20 is an enlarged view of a protrusion section not according to the invention, seen from the side of the pneumatic tire. Fig. 21 is a side view of a protrusion section not according to the invention. Fig. Figure 22 is a side view of a pneumatic tire according to another embodiment of the present invention. Fig. Figure 23 is a side view of a pneumatic tire according to another embodiment of the present invention. Fig. Figure 24 is a side view of a pneumatic tire according to another embodiment of the present invention. Fig. Figure 25 is a side view of a pneumatic tire according to another embodiment of the present invention. Fig. Figure 26 is a side view of a pneumatic tire according to another embodiment of the present invention. Fig. Figure 27 is a side view of a pneumatic tire according to another embodiment of the present invention. Fig. Figure 28 is a side view of a pneumatic tire according to another embodiment of the present invention. Fig. Figure 29 is a side view of a pneumatic tire according to another embodiment of the present invention. Fig. Figure 30 is a table showing results of performance tests of pneumatic tires according to examples not in accordance with the invention. Description of embodiments

[0018] Fig. Figure 1 is a meridian cross-sectional view of a pneumatic tire according to the present embodiment.

[0019] In the following description, "tire radial direction" refers to the direction perpendicular to the axis of rotation P (see Fig. 2) of a pneumatic tire 1. “Inward in the tire radial direction” refers to the direction that leads toward the axis of rotation P in the tire radial direction. “Outward in the tire radial direction” refers to the direction that leads away from the axis of rotation P in the tire radial direction.

[0020] "Tire circumference direction" refers to the circumferential direction whose central axis is the axis of rotation P. "Tire width direction" also refers to the direction parallel to the axis of rotation P. "Inward in tire width direction" refers to the direction toward an equatorial plane of the tire (tire equator line) CL in the tire width direction. "Outward in tire width direction" refers to the direction away from the tire equatorial plane CL in the tire width direction. "Tire equatorial plane CL" refers to a plane perpendicular to the axis of rotation P of the tire 1 and passing through the center of a tire width of the tire 1. "Tire width" is the width in the tire width direction between components located at the outer edges in the tire width direction, or in other words, the distance between the components furthest from the tire equatorial plane CL in the tire width direction.“Tire equator line” refers to the line in the circumferential direction of the pneumatic tire 1 that lies on the tire equatorial plane CL. In the present embodiment, the tire equator line and the equatorial plane of the tire are designated with the same reference numeral CL.

[0021] As in Fig. As illustrated in Figure 1, the pneumatic tire 1 includes a tread section 2, shoulder sections 3 on opposite sides of the tread section 2, and sidewall sections 4 and bead sections 5, which follow one another in this order from the shoulder sections 3. The pneumatic tire 1 also includes a carcass layer 6, a belt layer 7, and a belt reinforcement layer 8.

[0022] The tread section 2 is made of a rubber material (tread rubber) and is exposed on the outermost side of the pneumatic tire 1 in the radial direction, its surface forming the contour of the pneumatic tire 1. A tread surface 21 is formed on an outer circumferential surface of the tread section 2, in other words, on a road contact surface that comes into contact with a road surface when driving. The tread surface 21 is provided with a plurality of main grooves 22 (four in the present embodiment), which are straight main grooves extending in the circumferential direction parallel to the tire equator line CL. Furthermore, the plurality of main grooves 22 form a plurality of rib-like web sections 23 in the tread surface 21, extending in the circumferential direction and parallel to the tire equator line CL.Furthermore, although not shown in the drawings, lug grooves are provided in the tread surface 21, intersecting the main grooves 22 in each of the rib sections 23. The rib sections 23 are subdivided into a multitude of segments in the tire's circumferential direction by the lug grooves. Additionally, lug grooves are formed on the outermost side of the tread section 2 in the tire's width direction, such that they open outwards in the tire's width direction. It should be noted that the lug grooves can have a shape that is connected to the main grooves 22 or a shape that is not connected to the main grooves 22.

[0023] The shoulder sections 3 are sections of the tread section 2, arranged on both outer sides in the tire width direction. Additionally, the sidewall sections 4 are exposed at the outermost edges of the pneumatic tire 1 in the tire width direction. The bead sections 5 each enclose a tire bead core 51 and a bead filler 52. The tire bead core 51 is formed by winding a tire bead wire, which is a steel wire, into a ring shape. The bead filler 52 is a rubber material arranged in the space formed by folding over an end section of the carcass layer 6 in the tire width direction at the position of the bead core 51.

[0024] The end sections of the carcass layer 6, in the tire width direction, are folded over the pair of bead cores 51 from an inside to an outside, and the carcass layer 6 is stretched in a torus shape in the tire circumference direction to form the tire skeleton. The carcass layer 6 is made of carcass cord threads (not illustrated) coated with coating rubber, arranged side by side at an angle to the tire circumference along the tire meridian direction. The carcass cord threads are made of organic fibers (e.g., polyester, rayon, nylon, and the like). The carcass layer 6 is provided with at least one layer.

[0025] The belt layer 7 has a multi-layered structure in which at least two belts 71, 72 are layered on top of each other. In the tread section 2, the belt layer 7 is located outside the carcass layer 6 in the tire radial direction, i.e., on its outer circumference, and covers the carcass layer 6 in the tire circumferential direction. The belts 71, 72 are made of cord threads (not shown) coated with coating rubber, which are arranged side by side at a predetermined angle with respect to the tire circumferential direction (for example, from 20° to 30°). The cord threads are made of steel or organic fibers (polyester, rayon, nylon, or the like). Furthermore, the belts 71, 72 overlap each other and are arranged such that the direction of the cord threads of the respective belts intersects.

[0026] The belt reinforcement layer 8 is arranged in the tire radial direction on the outside of the belt layer 7, i.e., on its outer circumference, and covers the belt layer 7 in the tire circumferential direction. The belt reinforcement layer 8 is made of cord threads (not illustrated) coated with rubber, arranged side by side in the tire width direction substantially parallel (±5°) to the tire circumferential direction. The cord threads are made of steel or organic fibers (polyester, rayon, nylon, or the like). The in Fig. The belt reinforcement layer 8 illustrated in Figure 1 is arranged to cover the end sections of the belt layer 7 in the tire width direction. The configuration of the belt reinforcement layer 8 is not limited to that described above. Although not shown in the drawings, a configuration can be used in which the belt reinforcement layer 8 is arranged to cover the entire belt layer 7. Alternatively, for example, a two-layer reinforcement configuration can be used in which the inner reinforcement layer (in the tire radial direction) is larger than the belt layer 7 in the tire width direction, so that it covers the entire belt layer 7, and the outer reinforcement layer (in the tire radial direction) is arranged to cover only the end sections of the belt layer 7 in the tire width direction.In another example, a configuration with two reinforcement layers can be used, where both reinforcement layers are arranged to cover only the end sections of the belt layer 7 in the tire width direction. In other words, the belt reinforcement layer 8 overlaps at least the end section of the belt layer 7 in the tire width direction. Furthermore, the belt reinforcement layer 8 is configured by winding a ribbon-shaped strip material (e.g., with a width of 10 mm) in the tire circumference direction.

[0027] Fig. Figure 2 is a side view of a pneumatic tire according to the present embodiment. Fig. Figures 3 to 8 are longitudinal section views of a protrusion segment. Fig. Figures 9 to 14 are cross-sectional views of a protrusion section.

[0028] The following description also refers to how in Fig. Figure 1 illustrates that the “tire sidewall section S” refers to a surface that extends uniformly outward from a ground contact edge T of the tread section 2 in the tire width direction, or in other words, an area extending outward from a rim test line R in the tire radial direction. Furthermore, “ground contact edge T” refers to both outermost edges in the tire width direction of an area where the tread surface 21 of the tread section 2 of the pneumatic tire 1 comes into contact with the road surface (horizontal surface) when the pneumatic tire 1 is mounted on a standard rim, inflated to normal internal pressure, and loaded with 70% of its normal load. The two outermost edges are continuous in the tire circumference direction.Furthermore, “rim inspection line R” refers to a line used to confirm whether the tire has been correctly mounted on the rim and is usually an annular convex line located closer to the outside in the tire radial direction than a rim flange and continuing in the tire circumferential direction along a section adjacent to the rim flange on a front surface of the bead sections 5.

[0029] It should be noted that "normal rim" refers to a "standard rim" as defined by the Japan Automobile Tyre Manufacturers Association (JATMA), a "design rim" as defined by the Tire and Rim Association (TRA), or a "measuring rim" as defined by the European Tyre and Rim Technical Organisation (ETRTO). "Normal inflation pressure" refers to a "maximum air pressure" as defined by JATMA, the maximum value in "tire load limits at various cold inflation pressures" as defined by the TRA, or "inflation pressures" as defined by the ETRTO.“Regular load” refers to a “maximum load capacity” as defined by JATMA, the maximum value in “TIRE LOAD LIMITS AT VARIOUS COLD INFLATION PRESSURES” as defined by TRA, or “LOAD CAPACITY” as defined by ETRTO.

[0030] In the case of the pneumatic tire 1 of the present embodiment, as in Fig. 1 and Fig. As illustrated in Figure 2, a protrusion section 9 is provided on at least one tire sidewall section S, the protrusion section 9 projecting outwards beyond a tire sidewall surface Sa corresponding to the profile of the surface of the tire sidewall section S. The protrusion section 9 is made of a rubber material (the same rubber material as that forming the tire sidewall section S, or a different rubber material) and is designed as a comb extending longitudinally along the tire sidewall surface Sa of the tire sidewall section S in a direction that intersects the tire's circumferential or radial direction. As shown in Figure 2, the protrusion section 9 is made of a rubber material (the same rubber material as that forming the tire sidewall section S, or a different rubber material) and is designed as a comb extending longitudinally along the tire sidewall surface Sa of the tire sidewall section S in a direction that intersects the tire's circumferential or radial direction. Fig. As illustrated in Figure 2, the direction of travel (longitudinal direction) is a straight line L connecting the ends 9D. The protrusion section 9 is designed such that the direction of travel (longitudinal direction) represented by the straight line L coincides with the tire's circumferential direction and radial direction, as shown in Figure 2. Fig. Figure 2 illustrates the intersection. Although not illustrated in the drawings, the protrusion section 9 can be configured such that its direction of travel intersects the tire radial direction only as a tangent along the tire circumferential direction, or only the tire circumferential direction along the tire radial direction. A plurality of protrusion sections 9 are arranged in the tire circumferential direction.

[0031] In the present embodiment, for example, as in Fig. As illustrated in Figure 2, the protruding section 9, when viewed from the side of the pneumatic tire 1, extends in the longitudinal direction and curves in a C-shape. The protruding section 9 is not limited to being curved and, viewed from the side of the pneumatic tire 1, can be linear in the longitudinal direction, can be V-shaped, can be S-shaped, can have a meandering configuration, or can be zigzag-shaped. Furthermore, in each configuration, the longitudinal direction refers to a straight line connecting the ends 9D.

[0032] In cross-section along the longitudinal direction, which is in Fig. As illustrated in Figures 3 to 8, the protrusion section 9 includes an outer contour 9P projecting from the tire sidewall Sa, a plurality of main outer contour sections 9P1 with different curvatures to form an outer contour mainly between the ends 9D, and a connecting section 9P2 that connects the formed main outer contour sections 9P1. Fig. Figures 3 to 8 are schematic diagrams illustrating the tire sidewall Sa in a plane and the outer contour 9P with two main outer contour sections 9P1 and a connecting section 9P2 linking the two, showing only the Fig. 4 according to the invention. The pneumatic tire 1 of the present embodiment includes, although not illustrated in the drawings, a configuration in which the outer contour 9P has three or more main outer contour sections 9P1 and two or more connecting sections 9P2, which connect the main outer contour sections 9P1.

[0033] The main outer contour sections 9P1 are each formed along a circle of curvature with an arbitrary curvature. The main outer contour sections 9P1 each enclose a straight line with a curvature of 0. As in Fig. As illustrated in Figure 3, the main outer contour sections 9P1 do not, according to the invention, each form a circle of curvature whose center point is located closer to the inner surface of the tire than to the sidewall surface Sa, with the circle of curvature curving towards the outside of the tire. According to the invention, as shown in Figure 3, the main outer contour sections 9P1 each form a circle of curvature whose center point is located closer to the inner surface of the tire than to the outer surface of the tire Sa, and the circle of curvature curves towards the outer surface of the tire. Fig. Figure 4 illustrates that in the main outer contour sections 9P1 with the connecting section 9P2 in between, at least one of the main outer contour sections 9P1 forms a circle of curvature in the longitudinal direction, the center of which is located closer to the outside of the tire than to the tire sidewall Sa, wherein the circle of curvature is recessed towards the inside of the tire.

[0034] The connecting section 9P2 connects the main outer contour sections 9P1 and is connected to each of the main outer contour sections 9P1 via a point of curvature. The connecting section 9P2 can be configured as a point such that the points of curvature connected to the main outer contour sections 9P1 coincide at a single point, as shown in Fig. 3, Fig. 4 and Fig. 8 illustrated, or have a predetermined longitudinal distance between the points of curvature connected to the main outer contour sections 9P1, as in the non-inventive Fig. Figures 5 to 7 illustrate this. If the connecting section 9P2 has a predetermined longitudinal distance, the connecting section 9P2 can be formed in a convex shape so that it is separated from the tire sidewall Sa towards the outside of the tire, as shown in Fig. Figure 5 illustrates that the connecting section 9P2 can be formed in a linear shape, as shown in Fig. 6 illustrates, or may be formed in a concave shape so that it approaches the inside of the tire with respect to the tire sidewall Sa, as in Fig. Figure 7 illustrates this. If the connecting section 9P2 is assumed to be a corner located between the main outer contour sections 9P1, then the connecting section 9P2 is configured as a protruding corner where two main outer contour sections 9P1 are in contact with each other, with the corner projecting outwards from the tire sidewall Sa. In other words, no configuration is included in which the connecting section 9P2 is configured as a recessed corner that is recessed towards the inside of the tire with respect to the tire sidewall Sa when the connecting section 9P2 is a corner.

[0035] A cross-section of the protrusion section 9 is described, which runs perpendicular to the direction of travel (straight line L). The in Fig. The illustrated protrusion section 9 has a rectangular cross-section. The one in Fig. The protrusion section 9 illustrated in Figure 10 has a triangular cross-section. The one in Fig. Figure 11 illustrates protrusion section 9, which has a trapezoidal cross-section. Without further ado... Fig. 9 to 11 are limited and, although not clearly illustrated in the drawings, the protrusion section 9 can have a polygonal cross-section. Even if the cross-section of the protrusion section 9 in Fig. Figures 9 to 11 illustrate a corner section; the corner section can also be C-chamfered or R-chamfered. The section shown in Fig. The illustrated protrusion section 9 has a semicircular cross-section. Without referring to the Fig. 12 to be limited and although not clearly illustrated in the drawings, the cross-section of the protrusion section 9 can also have a semi-oval shape, a semi-elliptical shape or any other arc shape. Even if the in Fig. The illustrated protrusion sections 9 to 12 are each designed to rise directly from the tire sidewall Sa, as shown in Fig. Figure 13 illustrates that the rising section can be smooth with an arc section, or the rising section can have a step section, as shown in Fig. 14 illustrates that the cross-section of the protrusion section 9 need not be symmetrical to the left and right of the drawings, as shown in the diagram. Fig. 9 to 14 illustrates, but may have an asymmetrical shape.

[0036] Furthermore, in the protrusion section 9, the outer contour 9P is marked with a Fig. Figures 3 to 8 illustrate the longitudinal section described above, formed along a ridge line, with the corner section (including the chamfer treatment) in the section shown. Fig. Figures 9 to 11, 13, and 14 illustrate the cross-section described above, which is continuous in the longitudinal direction. That is to say, the cross-section shown in Figures 9 to 11, 13, and 14 is continuous in the longitudinal direction. Fig. The longitudinal section illustrated in sections 3 to 8 is viewed along a ridge line, with the corner section in Fig. 9 to 11, 13 and 14 are continuous in the longitudinal direction. Furthermore, in the protrusion section 9, the outer contour 9P is defined by a Fig. Figures 3 to 8 illustrate the longitudinal section described above, formed along a plane in which the sides are in the Fig. The cross-sections described above, illustrated in sections 9 to 14, are continuous in the longitudinal direction. In other words, the cross-section is formed in the... Fig. Figures 3 to 8 illustrate longitudinal section along a plane in which the sides are oriented longitudinally in Fig. 9 to 14 are continuously trained.

[0037] As described above, the pneumatic tire 1 of the present embodiment includes a plurality of protrusion sections 9 extending along the tire sidewall Sa of the tire sidewall section S, intersecting the tire circumferential direction or the tire radial direction longitudinally and provided at intervals in the tire circumferential direction, and each of the protrusion sections 9 is designed to include a plurality of main outer contour sections 9P1 with different curvatures and a connecting section 9P2 connecting the main outer contour sections 9P1, the outer contour 9P projecting from the tire sidewall Sa in a longitudinal section.

[0038] The operating principle of pneumatic tire 1 is described. Fig. 15 and Fig. Figure 16 are explanatory diagrams of the operating principle of a state-of-the-art pneumatic tire. Fig. 17 to the non-inventive Fig. Figure 19 are explanatory diagrams of the mode of operation of a pneumatic tire according to the present embodiment.

[0039] As in Fig. As illustrated in Figure 15, a prior art pneumatic tire 11, which does not include a protruding section 9, is mounted on a rim 50 for installation on a vehicle 100 and is thus arranged in a wheel well 101 of the vehicle 100. When the pneumatic tire 11 rotates in the direction of rotation Y1 in this state, the vehicle 100 moves in the direction Y2. When the vehicle 100 moves, the airflow around the pneumatic tire 11 stagnates. To avoid this stagnation, air then spreads outside the wheel well 101 away from a side surface 102 of the vehicle 100, as shown in Figure 15. Fig. Figure 16 illustrates what causes air resistance.

[0040] To counteract this phenomenon, the pneumatic tire 1 of the present embodiment is mounted on the rim 50 for installation on the vehicle 100 and arranged in the wheel arch 101 of the vehicle 100, as shown in Fig. Figure 17 illustrates this. When the pneumatic tire 1 rotates in the direction of rotation Y1 in this state, the vehicle 100 travels in the direction Y2. As the vehicle 100 travels, the protruding sections 9, which rotate in the direction of rotation Y1, generate turbulence in the air around the pneumatic tire 1 and minimize the airflow stagnation described above. In particular, a turbulent flow boundary layer is generated in the upper section of the pneumatic tire 1 as it rotates (on the side above the axis of rotation P). This promotes the flow of air around the pneumatic tire 1. As a result, as shown in Figure 17, the following applies: Fig. Figure 18 illustrates how the propagation of air away from the side surface 102 of the vehicle 100 on the outside of the wheel arch 101 is suppressed in order to reduce the air resistance generated on the vehicle 100. The reduction in air resistance leads to an improvement in the fuel consumption figures of the vehicle 100.

[0041] In particular, in the pneumatic tire 1 of the present embodiment, the outer contour 9P of the protrusion section 9 includes a plurality of main outer contour sections 9P1 with different curvatures and a connecting section 9P2 that joins the main outer contour sections 9P1, such that the airflows along the main outer contour sections 9P1 with different curvatures collide at the position of the connecting section 9P2 to generate a vortex with the connecting section 9P2 as the starting point, thereby supporting the generation of the turbulent flow boundary layer. As a result, the airflow at the pneumatic tire 1 is further promoted, and the propagation of air away from the side surface 102 of the vehicle 100 on the outside of the wheel housing 101 is further suppressed, thus improving the effect of reducing the air resistance generated at the vehicle 100.

[0042] The vortex described above, with the connecting section 9P2 as its starting point, occurs because the outer contour 9P of the protrusion section 9 runs along the crest line (the corner section in the cross-section of Fig. 9 to 11, 13 and 14) of the protrusion section 9. Accordingly, the outer contour 9P is preferably formed longitudinally along the crest line of the protrusion section 9.

[0043] Furthermore, the vortex described above occurs with the connecting section 9P2 as its starting point, since the outer contour 9P of the protrusion section 9 runs along the surface of the protrusion section 9 (the side in longitudinal section of Fig. 9 to 14). Accordingly, the outer contour 9P is preferably formed in the longitudinal direction along the surface of the protrusion section 9.

[0044] Furthermore, in the case of the pneumatic tire 1 of the present embodiment, as in Fig. 3 to 8 illustrated, showing only the Fig. 4 according to the invention, the outer contour 9P preferably includes the main outer contour sections 9P1 and the connecting section 9P2, which are formed in a region that excludes the region L0 from each of the ends 9D in the longitudinal direction to (L×0.05) with respect to the dimension L of the protrusion section 9 in the longitudinal direction.

[0045] In the region L0 from each end 9D of the protrusion section 9 longitudinally up to (L×0.05), the area of ​​the main outer contour sections 9P1 is small, and even if the airflows along the main outer contour sections 9P1 collide at the position of the connecting section 9P2, hardly any vortex is generated with the connecting section 9P2 as its origin. By forming the main outer contour sections 9P1 and the connecting section 9P2 in the region that excludes the region L0 from each end 9D of the protrusion section 9 longitudinally up to (L×0.05), a vortex with the connecting section 9P2 as its origin is appropriately generated, so that a significant reduction in the air resistance generated at the vehicle 100 can be achieved.Since an airflow adhering to the tire sidewall Sa is formed in the area L0, which lies near the tire sidewall Sa, due to the influence of air viscosity, and since it is unlikely that a vortex with the connecting section 9P2 as its starting point will be generated, the area L0 is excluded in order to generate a vortex with the connecting section 9P2 as its starting point in a suitable manner, so that the effect of reducing air resistance can be achieved. This is generated accordingly, as in the non-inventive design. Fig. Figure 8 illustrates that even in a case where a step section with a configuration similar to that of the connecting section 9P2 is provided in the region L0 from each of the ends 9D of the protrusion section 9 in the longitudinal direction, the step section is less likely to form a vortex and thus does not form the connecting section 9P2 in the present embodiment.

[0046] Furthermore, in the pneumatic tire 1 of the present embodiment, the outer contour 9P preferably comprises the main outer contour sections 9P1, each formed in a region L1 that is not smaller than (L×0.7) and not larger than (L×0.9), and the connecting section 9P2, which is formed in the region L2 that is not smaller than (L×0) and not larger than (L×0.3) with respect to the dimension L of the protrusion section 9 in the longitudinal direction. In this case, the region L1 of the main outer contour sections 9P1 is the sum of the regions L1 of all main outer contour sections 9P1, and if, in addition, a plurality of regions L2 of the connecting section 9P2 are present, the region L2 of the connecting section 9P2 is the sum of all regions L2 of the connecting section 9P2.

[0047] If the main outer contour sections 9P1 are each formed in the area L1 which is not smaller than (L×0.7) with respect to the dimension L of the protrusion section P in the longitudinal direction, it can be caused that the air flows along the main outer contour sections 9P1 collide with each other at the position of the connecting section 9P2 in order to generate a sufficiently strong vortex with the connecting section 9P2 as the starting point.If, in turn, one of the main outer contour sections 9P1 is formed in the area L1, which is not larger than (L×0.9) with respect to the dimension L of the protrusion section 9 in the longitudinal direction, the area L1 of the other of the main outer contour sections 9P1 is formed, which runs over the connecting section 9P2, and as a result, it can be caused that the air flows along both main outer contour sections 9P1 with the connecting sections 9P2 arranged between them collide at the position of the connecting section 9P2 in order to generate a sufficiently strong vortex with the connecting sections 9P2 as the starting point.In area L1, the connecting section 9P2 is fixed at a position away from the tire sidewall Sa towards the outside of the tire, and by fixing area L1 at a position away from the airflow that adheres near the tire sidewall Sa due to the viscosity of air, a vortex can be appropriately generated with the connecting section 9P2 as its starting point to achieve the effect of reducing air resistance.

[0048] Furthermore, in the pneumatic tire 1 of the present embodiment in Fig. 2, when the pneumatic tire 1 is mounted on the normal rim, inflated to the normal internal pressure, with a road surface G which is a horizontal surface, in contact with the ground under normal load (in Fig. 2 in a load state 0 (unloaded) is displayed), and in Fig. 2 rolls to the left by rotating in the direction of rotation Y on the road surface G, where a relative velocity U between the tire sidewall section S and the road surface G is expressed by U [m / s] = V × r / Q and a Reynolds number Re is represented by Re = U × Q / v, where V is a primary flow velocity (corresponding to the vehicle's speed) [m / s], Q is the distance from the road surface G to the axis of rotation P [m], r is the distance from the road surface G to the axis of rotation P [m], and v is the kinematic viscosity of the air in contact with the pneumatic tire 1 [m 2 / s], and the primary flow velocity V [m / s] is 27.8, the protrusion section 9 is provided at a position where a range of the Reynolds number Re 2000 < Re < 4 × 10 5 fulfilled.

[0049] In other words, in the pneumatic tire 1 of the present embodiment, the protrusion section 9 is provided at a position at a distance r [m] where the range of the Reynolds number Re at the primary flow velocity V [m / s] 2000 < Re < 4 × 10 5 fulfilled.

[0050] The operating principle of pneumatic tire 1 with this configuration is described. As in Fig. As illustrated in Figure 15, the prior art pneumatic tire 11, which does not have a protrusion section 9, rotates in the direction of rotation Y1, and when the vehicle 100 travels in the direction Y2, the airflow varies around the circumference of the pneumatic tire 11. Consequently, due to the airflow, as shown in Figure 15, the following occurs: Fig. Figure 16 illustrates that the amount of air flowing from the front end to the tire side section S at the ground contact section of the pneumatic tire 11 is smaller, the pressure in the free space between the road surface G and the vehicle floor surface increases, and lift is generated, which is a force to lift the vehicle 100 upwards.

[0051] Regarding such a phenomenon, as in Fig. Figure 17 illustrates that when the pneumatic tire 1 of the present embodiment rotates in the direction of rotation Y1 and the vehicle 100 drives in the direction Y2, a guiding (repelling) effect of air around the protrusion section 9 is increased by the protrusion section 9, which rotates and moves in the direction of rotation Y1, so that the pressure in the space between the road surface and the vehicle floor surface is reduced. In particular, at the ground contact section, which is the lower section of the pneumatic tire 1 when it rotates (the position of the distance r [m] where the Reynolds number Re 2000 < Re < 4 × 10 5 fulfilled), the guiding effect of air (repelling effect) through the protrusion section 9 is large, and as in Fig. As illustrated in Figure 18, at the ground contact section of the pneumatic tire 1, the amount of air flowing from the front end to the tire side section S increases, the pressure in the free space between the road surface and the vehicle floor surface decreases, and the lift, which is a force to lift the vehicle 100 upwards, is reduced.

[0052] The reduction of lift (lift reduction performance) leads to an increase in downforce, an improvement in the contact of the pneumatic tire 1 with the ground and an improvement in steering stability performance, which is a measure of the driving performance of the vehicle 100.

[0053] Furthermore, in the pneumatic tire 1 of the present embodiment, the area of ​​the total volume Vo of the protrusion sections 9 preferably meets the above-described Reynolds number Re range. 3 ] ≤ Vo ≤ 50000 [mm 3This means that by defining the total volume Vo of the protrusion sections 9 in the Reynolds number Re range described above, the guiding effect (repelling effect) by the protrusion sections 9 is increased, and the amount of air flowing from the front end to the tire sidewall section S increases at the ground contact section of the pneumatic tire 1, so that the pressure in the space between the road surface and the vehicle floor surface can be further reduced to further reduce lift.

[0054] Furthermore, the direction of rotation of the pneumatic tire 1 of the present embodiment is preferably indicated when mounted on a vehicle, and in the aforementioned range of the Reynolds number Re, as in Fig. As illustrated in Figure 2, at least one of the protrusion sections 9 is designed such that its direction of rotation from its initial edge to its final edge is inclined along the direction of rotation Y from the inside in the tire radial direction to the outside in the tire radial direction. Although not illustrated in the drawings, the direction of rotation is indicated by a marker (for example, an arrow pointing in the direction of rotation when the vehicle is moving forward) provided on the sidewall section 4 on the side surface of the tire, located on the outside of the tread section 2 in the tire width direction.In this configuration, air is directed from a top to a bottom of the front end at the ground contact section of the pneumatic tire 1, increasing the guiding effect (repelling effect) due to the protrusion sections 9 and increasing the amount of air flowing from the front end to the tire side section S at the ground contact section of the pneumatic tire 1, thus further reducing the pressure in the space between the road surface and the vehicle floor surface to further reduce lift.

[0055] As shown in the enlarged view of the protrusion section when viewed from the side of the pneumatic tire in the non-inventive version Fig. 20 and the side view of the protrusion section in the non-inventive Fig. As illustrated in Figure 21, the protrusion section 9 includes a central section 9A and apical sections 9B, which extend continuously from the central section 9A on each side in the direction of travel. The central section 9A is a section extending 25% (L × 0.25) of the length L of the protrusion section 9 in the direction of travel from a center 9C on each side in the direction of travel. The apical sections 9B are sections extending from both sides of the central section 9A in the direction of travel, excluding a region of 5% (L × 0.05) of the length L of the protrusion section 9 in the direction of travel from each of the ends 9D in the direction of travel. The length L of the protrusion section 9 in the direction of travel is the shortest distance between the ends 9D of the protrusion section 9.

[0056] The middle section 9A also includes a highest point hH, where the projection height h from the tire sidewall Sa is greatest. The tip section 9B also includes a lowest point hL, where the projection height h from the tire sidewall Sa is smallest. Fig. 21 The projection height h of the protrusion section 9 gradually increases in the direction of travel from one end 9D to the middle 9C and gradually decreases from the middle 9C to the other end 9D. In such a configuration, the highest point hH of the projection height corresponds to the middle 9C, and the lowest point hL corresponds to the ends of the tip sections 9B, i.e., the points that correspond to 5% of the length L from the ends 9D. It should be noted that although in Fig. 21 For the sake of simplicity, the projection height h of the protrusion section 9 is illustrated as transitioning into an arc shape in the direction of travel, but the outer contour 9P, as described above in longitudinal section, includes the majority of the main outer contour sections 9P1 and the connecting section 9P2 and is formed with a ridge line and a surface. Furthermore, the highest point hH can encompass the entire middle section 9A, and in such a configuration, the tip sections 9B can have a projection height h that gradually decreases from the middle section 9A.

[0057] According to the pneumatic tire 1 of the present embodiment, in the protrusion section 9, the central section 9A in the direction of travel encloses the highest point hH of the projection height h from the tire sidewall Sa, and the tip sections 9B, which are provided on both sides of the central section 9A in the direction of travel, each enclose the lowest point hL of the projection height h from the tire sidewall Sa. According to this pneumatic tire 1, the mass of the protrusion section 9 is reduced at the tip section 9B. As a result, a sudden change in mass from the tire sidewall Sa in areas near the tip sections 9B of the protrusion section 9 is prevented, the stability of the protrusion section 9 can be improved, and the uniformity in the circumferential direction of the tire can be improved, which in turn improves the uniformity.

[0058] The arrangement of the protrusion sections 9 is shown in a side view of the in Fig. Figures 2 and 22 to 29 illustrate the pneumatic tire. In the case of the Fig. 2, Fig. 22 and Fig. In the 23 illustrated pneumatic tires 1, the protrusion sections 9 are arranged at positions of the maximum tire width H (see Fig. 24 to 29). “Positions of maximum tire width H” are the largest positions in the tire width direction, excluding any patterns and alphanumeric characters, on a tire sidewall surface of the tire’s greatest overall width in the tire width direction when the pneumatic tire is mounted on the normal rim, inflated to normal internal pressure, and in an unloaded state. For tires provided with a rim protector (provided in the tire circumference direction and projecting outwards in the tire width direction) to protect the rim, the rim protector represents the outermost section in the tire width direction; however, the maximum tire width H, as defined in the present embodiment, does not include the rim protector. In the case of the Fig. In the pneumatic tires 1 illustrated in figures 24 to 29, the protrusion sections 9 are not located at the position of the maximum tire width H. In the case of the Fig. 24 and Fig. In the 25 illustrated pneumatic tires 1, the protrusion sections 9 are arranged outwards in the tire radial direction with respect to the maximum tire width H. In the case of the Fig. 26 and Fig. In the pneumatic tires 1 illustrated in 27, the protrusion sections 9 are arranged inwards in the tire radial direction with respect to the maximum tire width H. In the case of the Fig. 28 and Fig. In the 29 illustrated pneumatic tires 1, the protrusion sections 9 are arranged outwards in the tire radial direction with respect to the maximum tire width H or inwards in the tire radial direction with respect to the maximum tire width H.

[0059] In Fig. 2, Fig. 23, Fig. 25 to 27 on the inside in the tire radial direction Fig. 28 and in Fig. 29 the protrusion sections 9 are provided at intervals in the tire circumferential direction. Fig. 22, Fig. 24 and on the outside in the tire radial direction in Fig. 28 The protrusion sections 9, which are adjacent in the circumferential direction of the tire, are provided such that they partially overlap in the radial direction of the tire. In the case where the protrusion sections 9 are provided such that they partially overlap each other in the radial direction of the tire, the overlapping section is a section excluding the middle section 9A and is the tip section 9B or an end of the tip section 9B (within a region of 5% of the length L from the end 9D). Fig. 2, Fig. 22, Fig. 24, Fig. 26 and Fig. 28 The inclinations in the directions of the protrusion sections 9, which adjoin each other in the tire circumferential direction with respect to the tire circumferential direction and the tire radial direction, are equal. In the case of the Fig. 23, Fig. 25, Fig. 27 and Fig. In the pneumatic tires 1 illustrated in Figure 29, the inclinations in the directions of the protrusion sections 9, which adjoin each other in the tire circumferential direction with respect to the tire circumferential direction and the tire radial direction, are different. It should be noted that the arrangement of the protrusion sections 9 is not limited to those shown in Figure 29. Fig. 2 and 22 to 29 are illustrated.

[0060] It should be noted that the cross-section of the protrusion section 9, as shown in Fig. Figures 9 to 14 illustrate that, in the present embodiment, the cross-sectional area is largest at the highest point hH of the projection height h of the central section 9A, and the cross-sectional area is small at the lowest point hL of the projection height h of the tip section 9B. A width W in the transverse direction can follow the change in the projection height h and be largest at the highest point hH and smallest at the lowest point hL, or it may not change in this way at all.

[0061] Furthermore, in the pneumatic tire 1 of the present embodiment, the central section 9A of the protrusion section 9 preferably has a projection height h (highest point of the projection height h) in the range of 2 mm to 10 mm.

[0062] If the projection height h of the central section 9A is less than 2 mm, it is difficult to achieve the desired air diversion effect. If the projection height h of the central section 9A is greater than 10 mm, the amount of airflow colliding with the protruding section 9 increases. Consequently, air resistance is likely to increase. Therefore, the projection height h of the central section 9A is preferably in the range of 2 mm to 10 mm.

[0063] Furthermore, in the case of the pneumatic tire 1 of the present embodiment, as shown in Fig. Figures 9 to 14 illustrate the outer contour 9P preferably comprising the main outer contour sections 9P1 and the connecting section 9P2, which are formed in a region excluding a region h0 from the tire side surface Sa to (h × 0.05) with respect to the projection height h.

[0064] According to the pneumatic tire 1, the region h0 from the tire sidewall Sa to (h × 0.05) is a section in which the airflow along the tire sidewall Sa touches the protrusion section 9 and begins to change, and it is less likely that a vortex will occur with the connecting section 9P2 as its starting point. Accordingly, the main outer contour sections 9P1 and the connecting section 9P2 are formed in a region excluding the region h0 from the tire sidewall Sa to (h × 0.05) in order to appropriately generate a vortex with the connecting section 9P2 as its starting point, so that a significant reduction in the air resistance generated at the vehicle 100 can be achieved.Since the airflow attached to the tire sidewall Sa in the region h0, which lies near the tire sidewall Sa, is formed by the influence of air viscosity, it is unlikely that a vortex with the connecting section 9P2 as its starting point will be generated. Therefore, region h0 is excluded in order to appropriately generate a vortex with the connecting section 9P2 as its starting point, so that the effect of reducing air resistance can be achieved. It should be noted that an arc section (see . Fig. 13) or a stage section (see Fig. 14), which is an ascending section from the tire sidewall Sa, can influence the function of the outer contour 9P and is therefore preferably provided in the region h0, which hardly contributes to the function of the outer contour 9P.

[0065] Furthermore, as in Fig. Figure 2 illustrates the variation of the protrusion height h of each of the protrusion sections 9 per 1 degree in the circumferential direction of the pneumatic tire 1 in a section plane extending from the axis of rotation P in the radial direction of the tire, preferably 1 mm / degree or less.

[0066] According to pneumatic tire 1, by defining the variation in the protrusion height h of the protrusion sections 9 in the tire's circumferential direction, it is possible to suppress wind noise generated by the variation in the shape of the protrusion sections 9, thus reducing noise generated by wind noise from the protrusion sections 9. According to pneumatic tire 1, by defining the variation in the protrusion height h of the tire in the circumferential direction, including the protrusion sections 9, the uniformity in the tire's circumferential direction is improved, resulting in a significant improvement in uniformity.

[0067] Furthermore, as in Fig. Figure 2 illustrates the variation of the mass of the protrusion sections 9 per 1 degree in the circumferential direction of the pneumatic tire 1 in a section plane extending from the axis of rotation P in the radial direction of the tire, preferably 0.1 g / degree or less.

[0068] According to the pneumatic tire 1, by defining the variation in mass of the protrusion sections 9 in the circumferential direction of the tire, mass fluctuations of the protrusion sections 9 can be suppressed, and vibrations associated with the rotation of the pneumatic tire 1 can be suppressed, thus reducing noise generated by the protrusion sections 9 due to this vibration. Furthermore, according to the pneumatic tire 1, by defining the variation in mass of the tire in the circumferential direction, including the protrusion section 9, the uniformity in the circumferential direction of the tire is improved, resulting in a significant improvement in uniformity.

[0069] In the pneumatic tire 1 of the present embodiment, the protrusion sections 9 are preferably arranged at uneven intervals in the circumferential direction of the tire.

[0070] According to the pneumatic tire 1, the difference in frequency counteracts the uniformity of the protrusion sections 9 in the circumferential direction with respect to the airflow along the tire sidewall Sa of the tire sidewall section S, thus distributing and equalizing the sound pressure generated by the protrusion sections 9. As a result, the noise (sound pressure level) generated by the pneumatic tire 1 can be reduced.

[0071] It should be noted that the distances of the protrusion sections 9 seen from the side of the pneumatic tire 1 are given as angles between auxiliary lines (not shown) of the protrusion sections 9, the auxiliary lines being drawn from the axis of rotation P to the ends 9D of the raising sections 9 in the tire radial direction.Furthermore, to make the distances between the protrusion sections 9 uneven, a variety of measures can be taken, for example by ensuring that the protrusion sections 9 each have the same shape (projection height h, width W and length L in the direction of travel) and the same inclination at which the protrusion sections 9 intersect the tire circumferential direction and the tire radial direction, while changing the pitch in the tire circumferential direction, changing the shape (projection height h, width W and length L in the direction of travel) or changing the inclination at which the protrusion sections 9 intersect the tire circumferential direction and the tire radial direction.

[0072] Furthermore, when mounted on a vehicle, the pneumatic tire 1 preferably has a marked vehicle inside / outside orientation, and the protrusion sections 9 are preferably formed on at least the tire sidewall section S which corresponds to the vehicle outside.

[0073] In other words, when the pneumatic tire 1 of the present embodiment is mounted on the vehicle 100 (see Fig. 17) The orientation with respect to the inside and outside of the vehicle 100 is indicated in the direction of tire width. The orientation markings, although not shown in the drawings, can be indicated, for example, by indicators provided on the sidewall sections 4. Therefore, the side that, when mounted on the vehicle 100, faces the inside of the vehicle 100 is the “vehicle inside”, and the side that faces the outside of the vehicle 100 is the “vehicle outside”. It should be noted that the vehicle inside and vehicle outside markings are not limited to cases when mounted on the vehicle 100. For example, in cases where the pneumatic tire 1 is mounted on a rim, the orientation of the rim 50 (see Fig. 17) with respect to the inside and outside of the vehicle 100 in the direction of tire width is predetermined. Thus, the orientation with respect to the inside and outside of the vehicle in the direction of tire width is indicated in the case of mounting the pneumatic tire 1 on a rim.

[0074] The tire sidewall section S on the outside of the vehicle is exposed to the outside from the wheel arch 101 when the pneumatic tire 1 is mounted on the vehicle 100. Thus, by providing the protrusion sections 9 on the tire sidewall section S on the outside of the vehicle, the airflow can be pushed away from the vehicle, so that a significant effect of breaking up a vortex acting downwards from the wheel arch 101 can be achieved on the rear side of the pneumatic tire 1 in the direction of travel.

[0075] It should be noted that in the pneumatic tire 1 of the embodiment described above, the Fig. As illustrated in Figures 9 to 14, the protrusion section 9 preferably has a width W in the range of 0.5 mm to 10.0 mm in the transverse direction. If the width W of the protrusion section 9 in the transverse direction is less than the range described above, the area of ​​the protrusion section 9 that comes into contact with the airflow is small. This reduces the effectiveness of the air diversion by the protrusion section 9. If the width W of the protrusion section 9 in the transverse direction is greater than the range described above, the area of ​​the protrusion section 9 that comes into contact with the airflow is large. This causes the protrusion sections 9 to increase air resistance and tire weight. Thus, by appropriately adjusting the width W of the protrusion section 9 in the transverse direction, a significant effect of the air diversion by the protrusion section 9 can be achieved.

[0076] It should be noted that the pitch of the protrusion sections 9 in the circumferential direction of the tire can be equal to or different from the pitch of the lug grooves in the tread section 2 in the circumferential direction of the tire. Because the pitch of the protrusion sections 9 differs from the pitch of the lug grooves in the tread section 2 in the circumferential direction of the tire, the sound pressure generated by the protrusion sections 9 and the sound pressure generated by the lug grooves are dispersed and counteract each other due to the frequency difference. As a result, the pattern noise generated by the lug grooves can be reduced. It should be noted that the lug grooves with a different pitch than the protrusion sections 9 in the circumferential direction of the tire include all lug grooves in the rib-like web sections 23, which are defined in the tire width direction by the majority of main grooves 22.However, in order to achieve the effect of a significant reduction in the tread noise generated by the lug grooves, the pitch spacing of the protrusion sections 9 in the circumferential direction of the tire preferably differs from the pitch spacing of the lug grooves that are located furthest outwards in the direction of the tire width and closest to the protrusion sections 9. Examples not in the invention

[0077] In the present examples, tests for drag reduction performance and lift reduction performance were carried out on a plurality of types of pneumatic tires under different conditions (see Fig. 30).

[0078] In the lift reduction and drag reduction performance tests, a wind tunnel simulation test was conducted using a vehicle model with tire models of size 195 / 65R15 mounted on a body model of a motorized passenger car. The driving speed was set to the equivalent of 100 km / h. Using fluid analysis software and Lattice Boltzmann methods, the aerodynamic properties (lift reduction and drag reduction performance) were calculated. The evaluation results are expressed as index values ​​based on the calculated results, with the results of the prior art example defined as the reference value (100). In the index evaluation, higher values ​​indicate superior drag reduction and lift reduction performance.

[0079] In Fig. 30. The pneumatic tires of the prior art example and of Examples 1 to 17 each include the protrusion sections on the tire sidewall. The protrusion sections are located on the outside and inside of the vehicle in the Fig. 2 illustrated arrangements are provided and point out in a Fig. 10 illustrated side cross-sectional views, each one in Fig. Figure 21 illustrates the side shape, meaning that all examples are not according to the invention. In the pneumatic tire of the prior art example, the outer contour of each of the protrusion sections does not include the main outer contour section and the connecting section, and the arrangement of the protrusion sections lies outside the prescribed Reynolds number Re.

[0080] In contrast, in the pneumatic tires of Examples 1 to 17, the outer contour of each of the protrusion sections includes two main outer contour sections and a connecting section. Furthermore, in the pneumatic tires of Examples 1 to 8, the arrangement of the protrusion sections lies outside the prescribed Reynolds number Re. In the pneumatic tires of Examples 9 to 17, however, the arrangement of the protrusion sections lies within the prescribed Reynolds number Re. The region y from each end in the longitudinal direction is a region outside the main outer contour sections and the connecting section and represents region L0 in the embodiment described above. The region z of the main outer contour sections is a summation region of all main outer contour sections, in which all regions L1 of the embodiments described above are summed. The region v of the connecting section is formed by a point and is 0 in this example.

[0081] As can be seen from the test results of Fig. As can be seen in Figure 30, the pneumatic tires of the examples exhibit improved air resistance reduction performance. List of reference symbols 1 pneumatic tire 2. Tread section 21 Tread surface 22 Main groove 23 Bridge section 3 Shoulder section 4 Side wall section 5 bead section 50 rim 51 bead core 52 Bead fillers 6 Carcass layer 7th belt layer 71, 72 belts 8 Belt reinforcement layer 9 Protrusion section 9P Outer contour 9P1 Main outer contour section 9P2 connection section 9A middle section 9B Top Section 9C Middle 9D End 100 vehicles 101 Wheel arch CL tire equatorial plane G Road surface L Dimension of the protrusion section in the longitudinal direction L0 area from the end of the protrusion section in the longitudinal direction excluding the main outer contour section and the connecting section L1 area of ​​the main outer contour section L2 area of ​​the connecting section h0 area in the vertical direction from the tire sidewall excluding the main outer contour section and the connecting section P axis of rotation R rim test line S Tire sidewall section Sa tire sidewall T Ground contact edge W Width of the protrusion section h Protrusion height of the protrusion section

Claims

[1] Pneumatic tire (1) comprising a plurality of protrusion sections (9) which extend along a tire sidewall (Sa) of a tire sidewall section (S), intersect a tire circumferential direction or a tire radial direction in the longitudinal direction and are provided at intervals in the circumferential direction of the tire, each of the plurality of protrusion sections (9) having an outer contour comprising a plurality of main outer contour sections (9P1) with different curvatures and a connecting section (9P2) connecting the main outer contour sections (9P1), the outer contour projecting from the tire sidewall in a longitudinal section, wherein in the main outer contour sections (9P1) with the connecting section (9P2) in between at least one of the main outer contour sections (9P1) forms a circle of curvature in the longitudinal direction, the center of which is located closer to the outside of the tire than to the tire sidewall (Sa), the circle of curvature being recessed towards the inside of the tire. [2] Pneumatic tire (1) according to claim 1, wherein the outer contour is formed along a ridge line of each of the plurality of protrusion sections (9). [3] Pneumatic tire (1) according to claim 1, wherein the outer contour is formed along a surface of each of the plurality of protrusion sections (9). [4] Pneumatic tire (1) according to any one of claims 1 to 3, wherein the outer contour comprises the plurality of main outer contour sections (9P1) and the connecting section (9P2) formed in a region which excludes a region from each of the ends in the longitudinal direction to (L×0.05) PS:CZ:cc with respect to a dimension (L) of each of the plurality of protrusion sections (9) in the longitudinal direction. [5] Pneumatic tire (1) according to one of claims 1 to 4, wherein the outer contour is formed by the plurality of main outer contour sections (9P1) in a range from (L×0.7) to (L×0.9) and the connecting section (9P2) is formed in a range from (L×0) to (L×0.3) with respect to the dimension (L) of each of the plurality of protrusion sections (9) in the longitudinal direction. [6] Pneumatic tire (1) according to any one of claims 1 to 5, wherein, when the pneumatic tire (1) is mounted on a normal rim, is inflated to a normal internal pressure, is in contact with a road surface (G) which is a horizontal surface, is subjected to a normal load and is rolled on the road surface (G), in a case where a relative velocity U between the tire sidewall section (S) and the road surface (G) is expressed by U m / s = V × r / Q, a Reynolds number Re is expressed by Re = U × Q / v, where V is a primary flow velocity m / s opposite to the direction of rolling of the pneumatic tire (1), r is a distance m from the road surface (G) in the direction of the axis of rotation (P), Q is a distance m from the road surface (G) to the axis of rotation (P), and v is a kinematic viscosity of air m 2 / s and the primary flow velocity V m / s is 27.8, each of the plurality of protrusion sections (9) is provided at a position where a range of the Reynolds number Re 2000 < Re < 4 × 10 5 fulfilled. [7] Pneumatic tire (1) according to claim 6, wherein a total volume Vo of the plurality of protrusion sections (9) has a range of 1000 mm 3 ≤ Vo ≤ 50000 mm 3 in the range of the Reynolds number Re. [8] Pneumatic tire (1) according to any one of claims 1 to 7, wherein each of the plurality of protrusion sections (9) has a highest position of a projection height from the tire sidewall of 2 mm or higher and 10 mm or lower. [9] Pneumatic tire (1) according to any one of claims 1 to 8, wherein the variation of the protrusion height of each of the plurality of protrusion sections (9) per 1 degree in the tire circumferential direction is 1 mm / degree or less. [10] Pneumatic tire (1) according to any one of claims 1 to 9, wherein a variation in the mass of each of the plurality of protrusion sections (9) per 1 degree in the circumferential direction of the tire is 0.1 g / degree or less. [11] Pneumatic tire (1) according to any one of claims 1 to 10, wherein the majority of the protrusion sections (9) are arranged at uneven intervals in the circumferential direction of the tire. [12] Pneumatic tire (1) according to any one of claims 1 to 11, wherein a vehicle inside / outside orientation is characterized when mounting the pneumatic tire (1) on a vehicle (100) and the plurality of protrusion sections (9) are formed on at least one tire side section (S) which corresponds to an outside of the vehicle (100).

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