pneumatic tires

Abstract

Pneumatic tires (1), comprising: a plurality of survey sections (9) extending along a tire sidewall (Sa) of a tire sidewall section (S) in a direction that intersects a tire circumferential direction and a tire radial direction; the majority of survey sections (9), each of which includes the following a section (9A) in the middle of a direction of travel, defined as the section in the area of ​​25% of the length (L) of the raised section (9) in the direction of travel from a center (9C) on each side in the direction of travel, which includes a highest point (hH) of a protrusion height (h) from the tire sidewall (Sa), and in the direction of travel peak sections (9B), defined as sections extending from the central section (9A) on both sides in the direction of travel of 5% of the length (L) of the raised section (9) from the ends (9D) of the raised section (9), and which include a lowest point (hL) of a protrusion height (h) from the tire sidewall (Sa), wherein the lowest point (hL) is a point which corresponds to 5% of the length (L) from the ends (9D) of the raised section (9), and wherein the protrusion height (h) of the raised section (9) at the lowest point (hL) is less than the protrusion height (h) of the raised section (9) at the highest point (hH), the majority of survey sections (9), which include the following a radially outer raised section (91), wherein at least the middle section (9A) is arranged outwards from a widest point (H) of the tire in the tire radial direction, and a radially inner raised section (92), wherein at least the central section (9A) is arranged inwards from the widest point (H) of the tire in the tire radial direction, where a ratio of a total width SW to an outer diameter OD satisfies the relationship SW / OD ≤ 0.3, and where the ratio of an inner diameter RD to the outer diameter OD satisfies the relationship RD / OD ≥ 0.7.

Description

Technical area

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

[0002] JP 2013-018474 A describes a vehicle tire that includes a sidewall with curved raised sections. JP 2013-018474 A describes how the airflow against the sidewall does not flow naturally along the sidewall. Instead, the air moves within a wheel well, creating a downforce that pushes the upper part of a tread section downward. Note that the downforce generated reduces lift, a force that lifts the vehicle upward.

[0003] JP 2009-029380 A describes a pneumatic tire comprising a plurality of inner combs arranged in a region inward from a widest point of the tire in the tire radial direction, wherein the orientation of the inner combs is aligned with the tire radial direction; and a plurality of outer combs arranged in a region outward from the widest point of the tire in the tire radial direction, wherein the orientation of the outer combs is inclined with respect to the tire radial direction; wherein adjacent outer combs are inclined in the opposite direction with respect to the tire radial direction.JP 2009-029380 A describes how, by arranging ridges for generating turbulent flow in an optimized pattern in an inner and outer region in the tire radial direction on each side of the widest point of the tire, the effect of reducing the temperature of a tire side portion can be further increased and thus the durability can be increased.

[0004] Furthermore, WO 2014 / 024587 A1 (DE 11 2013 002 573 T5) describes a circumferential ridge portion extending longitudinally along mainly a tire circumferential direction, wherein the ridge portion is arranged outward from the widest point of the tire in the tire radial direction on at least one tire side portion. WO 2014 / 024587 A1 (DE 11 2013 002 573 T5) describes how, since the air flowing through the tire side portion is swirled by the circumferential ridge portion, a boundary layer of turbulent flow is generated around the pneumatic tire. This suppresses the expansion of the air flowing outward from the rear of the vehicle on the vehicle outer side. As a result, the spreading of the flowing air can be suppressed, the air resistance of the pneumatic tire can be reduced, and fuel economy can be improved.

[0005] It should be noted that WO 2011 / 135774 A1 describes a technology in which the air resistance around the tire can be reduced by lowering the overall width of the pneumatic tire and thus lowering the front protruding area (i.e. the protruding area when viewed from the direction of travel of the pneumatic tire).

[0006] US 2015 / 0 114 538 A1 discloses a pneumatic tire with land portions extending radially along the tire side surface. The land portions include center portions and peak portions. US 2011 / 0 088 826 A1 discloses a pneumatic tire with land portions optionally extending radially along the tire side surface in a direction intersecting a tire circumferential direction and a tire radial direction. The land portions include center portions and peak portions and extend along the entire tire side surface of the tire.

[0007] US 2009 / 0 032 161 A1 discloses a pneumatic tire with a concave-convex portion for generating turbulence, consisting of grooves and ribs along a tire side surface. The concave-convex portion contributes to a temperature reduction at the tire side surface. DE 11 2016 001 632 T5 discloses a pneumatic tire that can provide reduced lift and drag while maintaining good uniformity. The pneumatic tire includes a plurality of land portions extending along a tire side surface of a tire side portion in a direction intersecting a tire circumferential direction and a tire radial direction. Brief description of the invention: Technical problem

[0008] However, the pneumatic tires described in JP 2013-018474 A, JP 2009-029380 A and WO 2014 / 024587 A1 may experience a decrease in uniformity in the circumferential direction due to the raised sections, ridges or circumferentially arranged raised sections, resulting in a loss of good uniformity.

[0009] In view of this, one objective of the present invention is to create an air tire that can provide reduced lift and drag while maintaining good uniformity. Solution to the problem

[0010] To solve the problems and achieve the objectives described above, a pneumatic tire according to the present invention comprises a plurality of raised sections extending along a tire sidewall in a direction that intersects a tire circumferential direction and a tire radial direction; wherein each plurality of raised sections includes a central section in a direction of travel, defined as the section extending in the region of 25% of the length of the raised section in the direction of travel from a center on each side in the direction of travel, which includes a highest point of a projection height from the tire sidewall, and tip sections in the direction of travel, defined as sections extending from the central section on both sides in the direction of travel of 5% of the length of the raised section from the ends of the raised section.and include the lowest point of the protrusion height from the tire sidewall, wherein the lowest point is a point corresponding to 5% of the length from the ends of the raised section, and wherein the protrusion height of the raised section at the lowest point is less than the protrusion height of the raised section at the highest point, and wherein the plurality of raised sections includes a radially outer raised section, in which at least the central section is arranged outwards from the widest point of the tire in the tire radial direction, and a radially inner raised section, in which at least the central section is arranged inwards from the widest point of the tire in the tire radial direction; and a ratio of a total width SW to an outer diameter OD satisfies the relationship SW / OD ≤ 0.3.

[0011] In this case, a ratio of an inner diameter RD to an outer diameter OD satisfies the relationship RD / OD ≥ 0.7.

[0012] According to the pneumatic tire design, the raised sections, which rotate as the vehicle moves, cause the air to become turbulent, minimizing the slow airflow around the tire. More specifically, as the pneumatic tire rotates, the velocity of the air flowing along the lower part of the vehicle increases. This reduces the upward airflow, suppressing the upward air pressure. As a result, lift is reduced, the tire's contact with the road is improved, and steering stability, a measure of the vehicle's handling, is enhanced. Furthermore, as the pneumatic tire rotates, a boundary layer of turbulent flow is created in the upper section. This promotes airflow around the tire.As a result, the expansion of the air flow is suppressed, which reduces the tire's aerodynamic drag. This reduction in aerodynamic drag leads to an improvement in the vehicle's fuel consumption.

[0013] Furthermore, according to the pneumatic tire, the central portion in the extending direction intersecting the tire circumferential direction and the tire radial direction in the land portion includes the highest point of the protrusion height from the tire side surface, and the tip portions provided on both sides of the central portion in the extending direction each include the lowest point of the protrusion height from the tire side surface. Accordingly, the mass of the land portion is lower at the tip portions. As a result, a sudden change in the mass from the tire side surface is prevented in the area near the tip portions of the land portion, thereby improving uniformity in the tire circumferential direction, and thereby improving uniformity.

[0014] Furthermore, according to the pneumatic tire, the land portion includes the radially outer land portion having the center portion enclosing the highest point of the protrusion height outward from the widest point of the tire in the tire radial direction, and the radially inner land portion having the center portion enclosing the highest point of the protrusion height inward from the widest point of the tire in the tire radial direction. Thus, the air resistance is reduced at the widest point of the tire, where the pneumatic tire is widest in the tire transverse direction, making the air resistance there also high. As a result, the air resistance is further reduced.

[0015] Furthermore, according to the pneumatic tire of the present invention, since the ratio of the total width SW to the outer diameter OD satisfies the relationship SW / OD ≤ 0.3, the total width is smaller and the outer diameter larger than in a typical pneumatic tire. Thus, rolling resistance and air resistance during driving can be reduced. While tires with a large diameter, in particular, tend to exhibit increased air resistance, caused by the fact that a turbulent airflow is not generated due to a decrease in the relative speed between the sidewall section on the upper part of the tire and the air, the pneumatic tire of the present embodiment includes the raised section and satisfies the relationship of the ratio of the total width SW to the outer diameter OD.This allows the airflow at the side section to be swirled at the top of the tire, thereby maintaining a reduction in air resistance.

[0016] Thus, the pneumatic tire can provide reduced lift and drag while maintaining good uniformity.

[0017] In the pneumatic tire according to another embodiment of the present invention, the middle section and the tip sections of the radially outer raised section are arranged in the tire radial direction outwards from the widest point of the tire.

[0018] According to the pneumatic tire design, because the peak sections are not positioned beyond the widest point of the tire, the air resistance at the widest point of the tire, where the tire is widest in the lateral direction, is reduced, thus reducing air resistance there as well. Consequently, the effect of significantly reduced air resistance can be achieved.

[0019] In the pneumatic tire according to another embodiment of the present invention, the middle section and the tip sections of the radially inner raised section are arranged inwards in the tire radial direction from the widest point of the tire.

[0020] According to the pneumatic tire design, because the tip sections are not positioned beyond the widest point of the tire, the mass at the widest point, where the tire is widest in the transverse direction and air resistance is also high there, is reduced. As a result, the effect of significantly reduced air resistance can be achieved.

[0021] In the pneumatic tire according to another embodiment of the present invention, a change in the mass of the raised section in the tire circumferential direction per 1 degree in the tire circumferential direction is 0.2 g / degree or less.

[0022] According to the pneumatic tire design, by precisely controlling the change in mass of the raised section in the tire's circumferential direction, the uniformity in that direction is improved. Consequently, a significant improvement in uniformity can be achieved.

[0023] In the pneumatic tire according to another embodiment of the present invention, the central section of the raised section has a projection height in the range of 1 mm to 10 mm.

[0024] If the protrusion height of the central section is less than 1 mm, the effect of accelerating the airflow along the lower section of the vehicle and generating a boundary layer of turbulent flow is difficult to achieve. If the protrusion height of the central section is greater than 10 mm, the amount of airflow colliding with the raised section increases. Consequently, drag is likely to increase. Therefore, to achieve the effect of a significant reduction in lift and drag, the protrusion height of the central section is preferably in the range of 1 mm to 10 mm.

[0025] In the pneumatic tire according to another embodiment of the present invention, the raised section projects 5 mm or less in a tire transverse direction from a tire cross-sectional width at the widest point of the tire when the pneumatic tire is mounted on a normal rim, inflated to a normal internal pressure, in an unloaded state and viewed in a meridional cross-section.

[0026] If the raised section protrudes more than 5 mm outwards in the tire's transverse direction from the tire's cross-sectional width at its widest point, the amount of airflow colliding with the raised section is increased. Consequently, the drag of the raised section is likely to increase. By predefining the area in which the raised section protrudes outwards in the tire's transverse direction from the tire's cross-sectional width at its widest point, the increase in drag caused by the raised section can be suppressed, and the effect of the raised section significantly improving slow airflow can be maintained.

[0027] In the pneumatic tire according to another embodiment of the present invention, a groove is formed on a surface of the land portion.

[0028] According to the pneumatic tire design, the stiffness of the raised section is reduced due to the groove. Consequently, a decrease in ride comfort resulting from the increased rigidity of the tire sidewall is mitigated. Furthermore, the groove reduces the mass of the raised section. Therefore, a decrease in uniformity resulting from the increased mass of the tire sidewall is mitigated.

[0029] In the pneumatic tire according to another embodiment of the present invention, a depressed portion is formed on a surface of the land portion.

[0030] According to the pneumatic tire design, the stiffness of the raised section is reduced due to the presence of the recessed section. Consequently, a decrease in ride comfort resulting from the increased rigidity of the tire sidewall is mitigated. Furthermore, the recessed section reduces the mass of the raised section. This, in turn, mitigates a decrease in uniformity that would otherwise occur due to the increased mass of the tire sidewall. Finally, the recessed section and the groove further enhance the effects described above.

[0031] In the pneumatic tire according to another embodiment of the present invention, the plurality of land portions are arranged at uneven intervals in the tire circumferential direction.

[0032] According to the pneumatic tire, by counteracting the periodicity of the land portions in the tire circumferential direction with respect to the airflow along the tire side surface of the tire side portion, the difference in frequency disperses and equalizes the sound pressure generated by the land portions. As a result, noise can be reduced.

[0033] In the pneumatic tire according to another embodiment of the present invention, an orientation with respect to a vehicle inside / outside is prescribed when the pneumatic tire is mounted on a vehicle, and the plurality of land portions are formed at least on a tire side portion corresponding to a vehicle outside.

[0034] According to the pneumatic tire design, the sidewall section on the outside of the vehicle protrudes beyond the tire housing when the tire is mounted. Because the raised sections of the tire sidewall are located on the outside of the vehicle, the airflow can be directed towards the outside of the vehicle. This significantly reduces lift and drag.

[0035] Advantageous Effects of the Invention The pneumatic tire according to an embodiment of the present invention can provide reduced lift and drag while maintaining good uniformity. Brief description of the drawings Fig. 1 is a meridian cross-sectional view of a pneumatic tire according to an embodiment of the present invention. Fig. Figure 2 is a meridian cross-sectional view of the entire pneumatic tire according to an embodiment of the present invention. Fig. Figure 3 is a table showing the coefficients defined by aspect ratios. Fig. Table 4 lists the specified rim widths, which are the values ​​derived from the products of the coefficients, as shown in the table of Fig. 3 defined, are obtained, are closest. Fig. Figure 5 is a side view of a pneumatic tire according to an embodiment of the present invention. Fig. Figure 6 is an enlarged view of a section of the survey as seen from the side of a pneumatic tire. Fig. Figure 7 is a side view of a survey section. Fig. Figure 8 is a side view of another example of a pneumatic tire according to an embodiment of the present invention. Fig. Figure 9 is a side view of another example of a pneumatic tire according to an embodiment of the present invention. Fig. Figure 10 is a side view of another example of a pneumatic tire according to an embodiment of the present invention. Fig. Figure 11 is a side view of another example of a pneumatic tire according to an embodiment of the present invention. Fig. Figure 12 is a side view of another example of a pneumatic tire according to an embodiment of the present invention. Fig. Figure 13 is a cross-sectional view of a survey section in the transverse direction. Fig. Figure 14 is a cross-sectional view of a survey section in the transverse direction. Fig. Figure 15 is a cross-sectional view of a survey section in the transverse direction. Fig. Figure 16 is a cross-sectional view of a survey section in the transverse direction. Fig. 17 is a cross-sectional view of a bump portion in the transverse direction. Fig. 18 is a cross-sectional view of a bump portion in the transverse direction. Fig. 19 is a cross-sectional view of a bump portion in the transverse direction. Fig. 20 is a cross-sectional view of a bump portion in the transverse direction. Fig. 21 is a cross-sectional view of a bump portion in the transverse direction. Fig. 22 is a cross-sectional view of a bump portion in the transverse direction. Fig. 23 is a cross-sectional view of a bump portion in the transverse direction. Fig. 24 is a cross-sectional view of a bump portion in the transverse direction. Fig. 25 is a diagram for explaining the function of a pneumatic tire according to an embodiment of the present invention. Fig. Figure 26 is a sketch illustrating the function of a pneumatic tire according to an embodiment of the present invention. Fig. Figure 27 is a meridian cross-sectional view of a section of a pneumatic tire according to an embodiment of the present invention. Fig. Figure 28 is an enlarged view of a raised section in which grooves are formed, as seen from the side of a pneumatic tire. Fig. 29 is a cross-sectional view along a line AA of Fig. 28. Fig. Figure 30 is an enlarged view of another example of a raised section in which grooves are formed, as seen from the side of a pneumatic tire. Fig. Figure 31 is an enlarged view of an elevation section in which depressions are formed, seen from the side of a pneumatic tire. Fig. 32 is a cross-sectional view along a line BB of Fig. 31. Fig. Figure 33 is an enlarged view of a raised section in which grooves and depressions are formed, as seen from the side of a pneumatic tire. Fig. Figure 34 is a table showing results of performance tests of pneumatic tires according to examples of the present invention. Fig. Figure 35 is a side view of a section of a pneumatic tire according to the prior art example. Description of embodiments

[0036] Embodiments of the present invention are explained in detail below with reference to the drawings.

[0037] Fig. Figure 1 is a meridian cross-sectional view of a pneumatic tire according to the present embodiment. Fig. Figure 2 is a meridian cross-sectional view of the entire pneumatic tire according to the present embodiment.

[0038] In the following description, "tire radial direction" refers to the direction perpendicular to the axis of rotation P of a pneumatic tire 1 (see Fig. 2) is. “Inward in the tire radial direction” refers to the direction leading toward the axis of rotation P in the tire radial direction. “Outward in the tire radial direction” refers to the direction leading away from the axis of rotation P in the tire radial direction. “Circular direction” denotes the circumferential direction whose central axis is the axis of rotation P. “Transverse direction” also denotes the direction parallel to the axis of rotation P. “Inward in the tire transverse direction” denotes the direction leading toward a tire equatorial plane CL (a tire equator line) in the tire transverse direction. “Outward in the tire transverse direction” denotes the direction leading away from the tire equatorial plane CL in the tire transverse direction. “Tire equatorial plane CL” denotes a plane perpendicular to the axis of rotation P of the pneumatic tire 1 and passing through the center of one tire width of the pneumatic tire 1."Tire width" is a width in the tire transverse direction between components located outward in the tire transverse direction, or in other words, the distance between the components farthest from the tire equatorial plane CL in the tire transverse direction. "Tire equator line" refers to the line along the tire 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 tire equatorial plane are both denoted by reference symbol CL.

[0039] As in Fig. As shown in Figure 1, the pneumatic tire 1, which is mainly used in passenger cars, comprises 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 respective shoulder sections 3. The pneumatic tire 1 also comprises a carcass layer 6, a belt layer 7, and a belt reinforcement layer 8.

[0040] The tread portion 2 is formed of rubber material (tread rubber) and is exposed on the outermost side of the pneumatic tire 1 in the tire radial direction, and its surface forms the pattern of the pneumatic tire 1. A tread surface 21 is formed on an outer peripheral surface of the tread portion 2, or in other words, on a road contact surface that comes into contact with a road surface during running. The tread surface 21 is provided with a plurality (four in the present embodiment) of main grooves 22, which are straight main grooves extending in the tire circumferential direction parallel to the tire equator line CL. Further, in the tread surface 21, a plurality of rib-like land portions 23 extending along the tire circumferential direction and parallel to the tire equator line CL are formed by the plurality of main grooves 22.Furthermore, although not explicitly shown in the drawings, lug grooves are provided in the tread surface 21, intersecting with the main grooves 22 in each of the rib sections 23. The rib sections 23 are subdivided into a plurality of segments by the lug grooves in the tire's circumferential direction. Additionally, lug grooves are formed on the outermost side of the tread section 2 in the tire's transverse direction, such that they open outwards in the tire's transverse direction. It should be noted that the lug grooves can have a shape in which they are connected to the main grooves 22, or a shape in which they are not connected to the main grooves 22.

[0041] The shoulder sections 3 are sections of the tread section 2, arranged transversely on both sides of the tire. Additionally, the sidewall sections 4 are exposed at the outermost edges of the pneumatic tire 1 in the transverse 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 a steel wire wound into a ring. The bead filler 52 is a rubber material located in a space created by folding over one end of the carcass layer 6 transversely at the position of the bead core 51.

[0042] The end sections of the carcass layer 6 in the tire transverse direction are folded from the inside out around the pair of bead cores 51, and the carcass layer 6 is stretched in a ring-shaped form in the tire circumferential direction to form the tire skeleton. The carcass layer 6 is formed from a plurality of carcass cord threads with a rubber coating (not shown) arranged in an orientation with respect to the tire circumferential direction that coincides with the tire meridian direction. The carcass cord threads are made of organic fibers (e.g., polyester, rayon, nylon, or the like). At least one carcass layer 6 is provided.

[0043] The belt layer 7 has a multi-layer structure, with at least two belts 71, 72 superimposed on one another. In the tread portion 2, the belt layer 7 is arranged outside the carcass layer 6 in the tire radial direction, i.e., on the outer circumference thereof, and covers the carcass layer 6 in the tire circumferential direction. The belts 71 and 72 include a plurality of cords (not shown) arranged in alignment at a predetermined angle (e.g., from 20° to 30°) to the tire circumferential direction and covered with a coating of rubber. The cords are made of steel or organic fibers (polyester, rayon, nylon, or the like). In addition, the belts 71 and 72 overlap each other and are arranged so that the direction of the cords of the respective belts intersects.

[0044] The belt reinforcement layer 8 is arranged outside the belt layer 7 in the tire radial direction, i.e., on its outer circumference, and covers the belt layer 7 in the tire circumferential direction. The belt reinforcement layer 8 encloses a plurality of cord threads (not shown) arranged transversely to the tire and substantially parallel (±5°) to the tire circumferential direction, and coated with a rubber coating. The cord threads are made of steel or organic fibers (polyester, rayon, nylon, or the like). Fig. The belt reinforcement layer 8 shown in Figure 1 is arranged to cover the end sections of the belt layer 7 in the tire's transverse 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 configuration with two reinforcement layers can be used, in which the inner reinforcement layer (in the tire's radial direction) is larger than the belt layer 7 in the tire's transverse direction, so that it covers the entire belt layer 7, and the outer reinforcement layer (in the tire's radial direction) is arranged to cover only the end sections of the belt layer 7 in the tire's transverse direction.In another example, a configuration with two reinforcement layers can be used, where each reinforcement layer is arranged to cover only the end sections of the belt layer 7 in the tire's transverse direction. In other words, the belt reinforcement layer 8 overlaps at least the end sections of the belt layer 7 in the tire's transverse direction. Furthermore, the belt reinforcement layer 8 consists of a ribbon-shaped strip material (e.g., 10 mm wide) wound in the tire's circumferential direction.

[0045] Fig. Figure 3 is a table showing the coefficients defined by the aspect ratios. Fig. Table 4 lists the specified rim widths, which are the values ​​derived from the products of the coefficients, as shown in the table of Fig. 3 defined, are obtained, are closest. Fig. 5 is a side view of a pneumatic tire according to an embodiment of the present invention. Fig. 6 is an enlarged view of a bump portion as seen from the side of the pneumatic tire. Fig. Figure 7 is a side view of the elevation section. Fig. Figures 8 to 12 are side views of other examples of a pneumatic tire according to the present embodiment. Fig. 13 to 24 are cross-sectional views of a raised section in the transverse direction. Fig. 25 and Fig. Figure 26 are graphics that explain the function of the pneumatic tire according to the present embodiment. Fig. 27 is a meridian cross-sectional view of a portion of the pneumatic tire according to the present embodiment. Fig. 28 is an enlarged view of a land portion in which grooves are formed, viewed from the side of a pneumatic tire. Fig. 29 is a cross-sectional view along a line AA of Fig. 28. Fig. 30 is an enlarged view of another example of a land portion in which grooves are formed, as seen from the side of a pneumatic tire. Fig. 31 is an enlarged view of a land portion in which recessed portions are formed, as seen from the side of a pneumatic tire. Fig. 32 is a cross-sectional view taken along a line BB of Fig. 31. Fig. 33 is an enlarged view of a land portion in which grooves and depressed portions are formed, as seen from the side of a pneumatic tire.

[0046] Herein, the overall width SW is the interval between the sidewall sections 4, which include any designs (patterns or alphanumeric characters on the tire sidewall surface) on the sidewall sections 4, when the pneumatic tire 1 is mounted on a regular rim, inflated to a regular internal pressure (for example, 230 kPa), and in an unloaded state. The outer diameter OD is the outer diameter of the tire under the same conditions, and the inner diameter RD is the inner diameter of the tire under the same conditions. It should be noted that the internal pressure of 230 kPa described above is chosen to specify the dimensions of the pneumatic tire, such as the overall width SW. All tire dimension parameters specified in this patent are determined with reference to an internal pressure of 230 kPa and in an unloaded state.However, it should be clarified that inflation to an internal pressure of 230 kPa is not necessary for the application of the present invention, and the pneumatic tire 1 according to the present invention exhibits the effects of the present invention when inflated to an internal pressure within the normally used range.

[0047] Furthermore, as in Fig. Figure 1, “tire sidewall section S”, refers to the surface that extends uniformly outward in the tire radial direction from a ground contact edge T of the tread section 2, or in other words, an area extending outward in the tire radial direction from a rim test line R. Furthermore, “ground contact edge T” refers to both outermost edges in the transverse direction of a region where the tread surface 21 of the tread section 2 of the pneumatic tire 1 comes into contact with the road surface when the pneumatic tire 1 is mounted on a standard rim, inflated to normal internal pressure, and loaded with 70% of its regular load. The ground contact edge T is continuous in the circumferential direction of the tire.Furthermore, “rim inspection line R” refers to a line used to confirm that the tire has been correctly mounted on the rim and is usually an annular, convex line that is closer to the outside in the tire radial direction than a rim flange and continues in the tire circumferential direction along a section near the rim flange on a front surface of the tire bead sections 5.

[0048] As in Fig. In Figure 1, the "widest point of the tire H" denotes the ends of the tire's cross-sectional width HW, where the width is greatest in the transverse direction. The "tire cross-sectional width HW" is the maximum overall tire width SW in the transverse direction, excluding any patterns or alphanumeric characters on a tire sidewall, when the pneumatic tire 1 is mounted on a standard rim, inflated to normal internal pressure, and unloaded. For tires equipped with a rim protector (provided in the circumferential direction and projecting outwards in the radial direction) to protect the rim, the rim protector represents the outermost section in the transverse direction; however, the tire cross-sectional width HW, as defined in this embodiment, does not include the rim protector.

[0049] Here, "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 internal pressure" refers to a "maximum air pressure" as defined by JATMA, a 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 “Maximum Load Capacity” as defined by JATMA, a maximum value in “TIRE ROAD LIMITS AT VARIOUS COLD INFLATION PRESSURES” as defined by TRA, and “LOAD CAPACITY” as defined by ETRTO.

[0050] In a pneumatic tire 1 of the present embodiment, as shown in Fig. As shown in Figure 2, the ratio of the total width SW to the outer diameter OD satisfies the relationship SW / OD ≤ 0.3 according to the invention. In the case of the pneumatic tire 1 of the present embodiment, the ratio of the inner diameter RD to the outer diameter OD satisfies the relationship RD / OD ≥ 0.7.

[0051] The rim used in the present embodiment has a rim diameter that is compatible with the inner diameter of the pneumatic tire 1 and has a nominal rim width that corresponds to the one specified in Fig. 4. The specified rim width Rm (mm) corresponds to the value that is closest to the value (Rm = K1 × Sn) resulting from the product of the nominal tire cross-sectional width Sn and the coefficient K1, which is determined according to the aspect ratio of the tire mounted on the rim according to ISO 4000-1:2001 in the correspondence table of Fig. 3 is described.

[0052] In the pneumatic tire 1 of the present embodiment, as in Fig. 5 to 7, at least one tire side portion S is provided with a land portion 9 that protrudes outward beyond a side surface Sa corresponding to the profile of the surface of the tire side portion S. The land portion 9 is formed of a rubber material (the same rubber material as that constituting the tire side portion S or a different rubber material) as a ridge that extends along the tire side surface Sa of the tire side portion S in a direction intersecting the tire circumferential direction and the tire radial direction. In the present embodiment, the land portion 9 shown in the drawings curves into a C-shape when viewed from the pneumatic tire 1 side.The elevation section 9 is not limited to being curved and can be linear when viewed from the side of the pneumatic tire 1, can be in a V-shape, can be in an S-shape, can have a meander configuration or a zigzag shape.

[0053] As in Fig. 6 and Fig. As shown in Figure 7, the survey section 9 includes a middle section 9A and tip sections 9B, which are designed to extend from the middle section 9A on each side in the direction of travel. The middle section 9A is the section extending 25% of the length L of the survey section 9 in the direction of travel from a center point 9C on each side in the direction of travel. The tip sections 9B are sections extending from the middle section 9A on both sides in the direction of travel, excluding 5% of the length L of the survey section 9 in the direction of travel from ends 9D in the direction of travel. The length L of the survey section 9 in the direction of travel is the shortest distance between the ends 9D of the survey section 9.

[0054] The middle portion 9A also includes a highest point hH at which the projection height h from the tire side surface Sa is the greatest. The tip portion 9B also includes a lowest point hL at which the projection height h from the tire side surface Sa is the smallest. Fig. 7. The height of the projection h of the elevation 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. With such a design, the highest point hH corresponds to the height of the projection h at the middle 9C, and the lowest point hL corresponds to the ends of the top sections 9B, i.e., the points that are 5% of the length L from the ends 9D. Note that the in Fig. Figure 7 shows the elevation height h of the elevation section 9 with an arc-shaped change in the direction of travel. However, this is not meant as a restriction, and the change can also be linear. Furthermore, the highest point hH can encompass the entire middle section 9A, and in such a configuration, the top sections 9B can have an elevation h that gradually decreases from the middle section 9A onwards.

[0055] As in Fig. Figure 5 shows that the raised section 9 in the area of ​​the tire sidewall section S includes a plurality of radially outer raised sections 91, which are arranged outwards from the widest point of the tire H in the tire radial direction, and a plurality of radially inner raised sections 92, which are arranged inwards from the widest point of the tire H in the tire radial direction. The radially outer raised sections 91 and the radially inner raised sections 92 are both arranged at predetermined intervals in the tire circumferential direction.

[0056] It should be noted that, as in Fig. As shown in Figure 8, the radially outer raised sections 91 can extend partially inwards in the tire radial direction beyond the widest point of the tire H. In such a design, the central section 9A is arranged outwards in the tire radial direction from the widest point of the tire H, and at least one of the tip sections 9B (or the region of 5% of the length L from the end 9D) extends inwards in the tire radial direction beyond the widest point of the tire H. Furthermore, in Fig. 8. All of the radially outer raised sections 91 extend partially inwards beyond the widest point of the tire H in the tire radial direction. However, this only applies to at least one of the majority of the radially outer raised sections 91. As in Fig. As shown in Figure 9, the radially inner raised sections 92 can extend partially outwards from the widest point of the tire H in the tire radial direction. In such a design, the central section 9A is arranged inwards from the widest point of the tire H in the tire radial direction, and at least one of the tip sections 9B (or the region of 5% of the length L from the end 9D) extends in the tire radial direction beyond the widest point of the tire H. Furthermore, in Fig. 9, all of the radially inner land portions 92 partially extend outward beyond the widest point of the tire H in the tire radial direction. However, this may only apply to at least one of the plurality of radially inner land portions 92. It should be noted that, although not shown in the drawings, the radially outer land portions 91 and the radially inner land portions 92 may each partially extend beyond the widest point of the tire H. Thus, the land portion 9 in the region of the tire side portion S includes a plurality of radially outer land portions 91, a main portion (the center portion 9A) being arranged outward from the widest point of the tire H in the tire radial direction, and a plurality of radially inner land portions 92, a main portion (the center portion 9A) being arranged inward from the widest point of the tire H in the tire radial direction.

[0057] It should be noted that in the case of tires equipped with a rim protection strip, the radially inner raised sections 92 may have a configuration in which an inner end section in the tire radial direction does not reach the rim protection strip, a configuration in which an inner end section in the tire radial direction reaches part of the height of the projection of the rim protection strip, or a configuration in which an inner end section in the tire radial direction reaches the height of the rim protection strip.

[0058] As in Fig. 5, Fig. 8 and Fig. As shown in Figure 9, the radially outer raised sections 91 and the radially inner raised sections 92 can be arranged such that they have a similar inclination with respect to the tire's circumferential direction and the tire's radial direction. Alternatively, as shown in Fig. 10, the radially outer protrusion portions 91 and the radially inner protrusion portions 92 may have opposite inclinations with respect to the tire circumferential direction and the tire radial direction. In addition, as shown in Fig. 11, the radially outer elevation portions 91 and the radially inner elevation portions 92 each have different inclinations with respect to the tire circumferential direction and the tire radial direction. As shown in Fig. As shown in Figure 12, the radially outer elevation sections 91 or the radially inner elevation sections 92 (the radially inner elevation sections 92 in Fig. 12) each exhibit different inclinations with respect to the tire's circumferential direction and the tire's radial direction. As in Fig. 8 and Fig. As shown in Figure 9, the radially outer raised sections 91 and the radially inner raised sections 92 can be arranged in equal numbers in the tire circumferential direction, or can be arranged as shown in Fig. 5, Fig. 10 and Fig. 11 shown, arranged in varying numbers in the direction of the tire's circumference.

[0059] The cross-sectional shape in the transverse direction perpendicular to the direction of the elevation sections 9 (the radially outer elevation sections 91, the radially inner elevation sections 92) can be a quadrilateral cross-sectional shape in the transverse direction, as formed by the elevation section 9 in Fig. 13 shown. The one in Fig. Section 9 of the survey, shown in Figure 14, has a triangular cross-sectional shape in the transverse direction. The section shown in Figure 14 has a triangular cross-sectional shape in the transverse direction. Fig. Section 9 of the survey shown in 15 has a trapezoidal cross-sectional shape in the transverse direction.

[0060] Similarly, the cross-sectional shape of the survey sections 9 can have an external form in the transverse direction based on curved lines. The in Fig. The raised portion 9 shown in Figure 16 has a semicircular cross-sectional shape in the transverse direction. Although not shown in the drawings, the cross-sectional shape of the raised portion 9 in the transverse direction may also have a semi-oval shape, a semi-elliptical shape, or any other arc shape.

[0061] Furthermore, the cross-sectional shape of survey section 9 can have an external form in the transverse direction based on a combination of straight and curved lines. The in Fig. Section 9 of the survey shown in Figure 17 has a cross-sectional shape in the transverse direction that is a four-sided shape with rounded corners. The section shown in Figure 17 has a cross-sectional shape that is four-sided with rounded corners. Fig. The elevation portion 9 shown in Figure 18 has a cross-sectional shape in the transverse direction which is a triangular shape with rounded corners. Furthermore, as shown in Figures Fig. Figures 17 to 19 show that the cross-sectional shape in the lateral direction of the tire elevations 9 has a shape in which the base section, which protrudes from the tire side section S, is curved.

[0062] In addition, the cross-sectional shape of the raised portion 9 in the transverse direction may be a combination of different shapes. Fig. 20 includes a quadrilateral upper section formed by a plurality of triangular shapes (two in Fig. 20) is given a zigzag shape. Fig. The elevation section 9 shown in Figure 21 includes a four-sided upper section tapered by a single triangular shape. Fig. Section 9 of the survey, as depicted in Figure 22, includes a four-sided upper section, which is designed as a four-sided depression. The section shown in Figure 22 includes a four-sided upper section, which is designed as a four-sided depression. Fig. The elevation section 9 shown in Figure 23 includes a four-sided upper section formed as a four-sided depression, with the projection height being different on each side of the depression. Fig. 24 includes a four-sided platform portion 9a formed to protrude from the tire side portion S. On the platform portion 9a, a plurality of four-sided shapes (two in Fig. 24). Although not shown in the drawings, the cross-sectional shape of the raised portion 9 in the transverse direction may further include a quadrilateral upper portion having a wave-like shape or have another shape.

[0063] Furthermore, in the present embodiment, the cross-sectional area of ​​the cross-sectional shape in the transverse direction of the raised section 9 is, as described above, 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 points hL of the projection height h of the tip sections 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 sometimes it may not change in this way at all.

[0064] The function of the pneumatic tire 1 is in Fig. Figure 25 illustrates this. When the pneumatic tire 1 is mounted on a rim 50 and then on a vehicle 100, the pneumatic tire 1 is positioned in a tire well 101 of the vehicle 100. When the pneumatic tire 1 rotates in direction Y1 in this position, the vehicle 100 moves in direction Y2. When the vehicle 100 is moving, the airflow in the vicinity of the pneumatic tire 1 has a low velocity. In response to the slow airflow, an upward airflow is generated in the wheel well 101. This, in turn, generates lift, that is, a force that lifts the vehicle 100 upward. Additionally, in response to the slow airflow, a cushion of air separates from the vehicle 100 and forms outside the tire well 101, thereby causing drag.

[0065] In light of this phenomenon, the pneumatic tire 1 of the present embodiment includes raised sections 9 that rotate in the direction of rotation Y1 when the vehicle 100 is moving. The raised sections 9 cause the air to swirl around the tire 1 and minimize the slow airflow described above. More precisely, in the lower section of the pneumatic tire 1, when the pneumatic tire 1 rotates (on the side below an axis of rotation P), the velocity of the air flowing along the lower section of the vehicle 100 is increased. This reduces the upward airflow in the tire housing 101, thereby suppressing the upward air pressure. As a result, lift can be suppressed.By suppressing lift (the lift-reducing property), a downward force is increased, the ground contact of the pneumatic tire 1 is improved, and steering stability is enhanced, which is a measure of the vehicle's driving performance. Furthermore, as the pneumatic tire 1 rotates, a boundary layer of turbulent flow is generated in the upper section of the pneumatic tire 1 (on the side above the axis of rotation P). This promotes airflow around the pneumatic tire 1. As a result, the propagation of the airflow is suppressed, thus reducing the air resistance of the pneumatic tire 1. The reduction in air resistance leads to an improvement in the fuel consumption figures of the vehicle 100. As in . Fig. As shown in Figure 26, this effect can be obtained by adjusting the inclination of the elevation sections 9 with respect to the tire circumferential direction and the tire radial direction. Fig. 25 is reversed.

[0066] Furthermore, according to the pneumatic tire 1 of the present embodiment, in raised section 9, the central section 9A, in the direction of travel intersecting the tire's circumferential and radial directions, 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. Accordingly, the mass of raised section 9 is lower at the tip sections 9B. Consequently, a sudden change in mass from the tire sidewall Sa in the area near the tip sections 9B of raised section 9 is prevented, thereby improving the uniformity in the tire's circumferential direction and thus further improving the uniformity.

[0067] Furthermore, according to the pneumatic tire 1 of the present embodiment, the land portion 9 includes the radially outer land portion 91 having the center portion 9A including the highest point hH of the protrusion height h outward from the widest point of the tire H in the tire radial direction, and the radially inner land portion 92 having the center portion 9A including the highest point hH of the protrusion height h inward from the widest point of the tire H in the tire radial direction. Thus, the air resistance is reduced at the widest point of the tire H where the pneumatic tire 1 is widest in the tire transverse direction, whereby the air resistance there also becomes high. As a result, the air resistance is further reduced.

[0068] Furthermore, according to the pneumatic tire 1 of the present embodiment, since the ratio of the total width SW to the outer diameter OD satisfies the relationship SW / OD ≤ 0.3 according to the invention, the total width is smaller and the outer diameter larger than in a typical pneumatic tire. Thus, rolling resistance and air resistance can be reduced during driving. While tires with a large diameter, in particular, tend to exhibit increased air resistance, caused by the fact that, due to a decrease in the relative speed between the sidewall section on the upper part of the tire (the upper position on the tire sidewall section S when the tire is mounted on a vehicle) and the air, no turbulent airflow is generated, the pneumatic tire 1 of the present embodiment includes the raised section 9 and satisfies the relationship of the ratio of the total width SW to the outer diameter OD.This allows the airflow at the side section to be swirled at the top of the tire, thereby maintaining a reduction in air resistance.

[0069] Thus, the pneumatic tire 1 of the present embodiment can provide reduced lift and drag while maintaining good uniformity.

[0070] In the pneumatic tire 1 of the present embodiment, the central section 9A and the tip sections 9B of the radially outer raised section 91 are preferably arranged outwards in the tire radial direction from the widest point of the tire H. In the pneumatic tire 1 of the present embodiment, the central section 9A and the tip sections 9B of the radially inner raised section 92 are preferably arranged inwards in the tire radial direction from the widest point of the tire H.

[0071] According to the pneumatic tire 1, because the tip sections 9B are not located beyond the widest point of the tire H, the air resistance at the widest point of the tire H, where the pneumatic tire 1 is widest in the transverse direction, is reduced, thus reducing the air resistance there as well. Consequently, the effect of a significantly reduced air resistance can be achieved.

[0072] Furthermore, as in Fig. Figure 5 shows the change in mass of the raised section 9 in the tire circumferential direction per 1 degree in the tire circumferential direction, subdivided by lines extending from the axis of rotation P in the tire radial direction, preferably 0.2 g / degree or less.

[0073] According to pneumatic tire 1, the uniformity in the tire's circumferential direction is improved by predetermining the change in mass of the raised section 9. Consequently, the uniformity is significantly improved.

[0074] Furthermore, in the pneumatic tire 1 of the present embodiment, the central section 9A of the raised section 9 preferably has a projection height h in the range of 1 mm to 10 mm.

[0075] If the projection height h of the central section 9A is less than 1 mm, the effect of accelerating the airflow along the lower section of the vehicle 100 and generating a boundary layer of turbulent flow is difficult to achieve. If the projection height h of the central section 9A is greater than 10 mm, the amount of airflow colliding with the raised section 9 increases. Consequently, drag is likely to increase. Therefore, to achieve the effect of a significant reduction in lift and drag, the projection height h of the central section 9A is preferably in the range of 1 mm to 10 mm.

[0076] As with the one in Fig. In the meridian cross-section of the pneumatic tire 1 of the present embodiment shown in Figure 1, the raised section 9 preferably projects 5 mm or less beyond a tire cross-sectional width HW at the widest point of the tire H in the tire width direction when the tire is mounted on a normal rim, inflated to normal internal pressure, and unloaded. In other words, the projection G, by which the raised section 9 projects outwards in the tire transverse direction, is as shown in Figure 1. Fig. 27 shown, from a reference line HL extending in the tire radial direction, based on the widest point of the tire H of the tire sidewall Sa, preferably 5 mm or less.

[0077] If the raised section 9 protrudes more than 5 mm outwards in the tire's transverse direction from the tire's cross-sectional width HW at its widest point H, the amount of airflow colliding with the raised section 9 is increased. Consequently, the air resistance of the raised section 9 is likely to increase. By predefining the area in which the raised section 9 protrudes outwards in the tire's transverse direction from the tire's cross-sectional width HW at its widest point H, the increase in air resistance caused by the raised section 9 can be suppressed, and the effect of the raised section 9 significantly improving the slow airflow can be maintained.In order to achieve these effects to a significant extent, the raised section 9 preferably does not project beyond the tire cross-sectional width HW at the widest point of the tire H in the transverse direction and can project 0 mm or less.

[0078] As in Fig. As illustrated in Figures 28 to 30, the pneumatic tire 1 of the present embodiment has a groove 9E which is preferably formed in the surface of the raised section 9.

[0079] According to the pneumatic tire 1, the rigidity of the land portion 9 is reduced because the groove 9E is formed. As a result, a decrease in ride comfort due to the tire side portion S being made into a rigid structure by the land portions 9 can be suppressed. In addition, by forming the groove 9E, the mass of the land portion 9 is reduced. As a result, a decrease in uniformity due to the land portions 9 increasing the mass of the tire side portion S can be suppressed.

[0080] Note that a plurality of the grooves 9E are provided at predetermined intervals with respect to the length L, as shown in Fig. 28, so that they intersect the extending direction of the raised portion 9. An angle θ at which the grooves 9E intersect the extending direction of the raised portion 9 is not particularly specified. However, the grooves 9E preferably have the same angle θ so that an extreme change in the mass of the raised portion 9 in the extending direction is suppressed. As shown in Fig. As shown in Figure 30, the grooves 9E preferably have the same angle θ (for example, θ = 90°) with respect to a tangent GL of a centerline SL passing through the center of the raised section 9 in the transverse direction, so that an extreme change in the mass of the raised section 9 in the direction of travel is suppressed. The grooves 9E preferably have a groove width of 2 mm or less, so that they have little aerodynamic influence, that is, their influence on the effect of increasing the airflow along the lower section of the vehicle 100 and the generation of a boundary layer of turbulent flow is minimal. As shown in Fig. 29, the grooves 9E preferably have a groove depth d1 equal to or less than the protrusion height h of the ridge portion 9, so that the ridge portion 9 is not divided halfway along the ridge portion 9, and the effect of enhancing the airflow along the lower portion of the vehicle 100 and generating a boundary layer of turbulent flow can be obtained. For example, the groove depth d1 of the grooves 9E is preferably equal to or less than 90% of the protrusion height h of the ridge portion 9. Note that the triangular shape of the ridge portion 9, viewed in a cross section in the transverse direction in Fig. 29 is just one example.

[0081] As in Fig. 31 and Fig. 32, the pneumatic tire 1 of the present embodiment has a depressed portion 9F preferably formed in the surface of the land portion 9.

[0082] According to the pneumatic tire 1, the stiffness of the raised section 9 is reduced because of the recessed section 9F. Consequently, a decrease in ride comfort due to the increased rigidity of the tire sidewall section S by the raised sections 9 can be mitigated. Furthermore, the recessed section 9F reduces the mass of the raised section 9. Therefore, a decrease in uniformity due to the increased mass of the tire sidewall section S by the raised sections 9 can be mitigated.

[0083] Note that a plurality of the recessed portions 9F are provided at predetermined intervals in the extending direction of the raised portion 9, as shown in Fig. 31. In embodiments in which the width W of the raised portion 9 changes in the extending direction, the recessed portions 9F preferably change their size according to the change in the width W, so that an extreme change in the mass of the raised portion 9 in the extending direction is suppressed. The recessed portions 9F preferably have an opening diameter of 2 mm or less, so that they have little aerodynamic influence, that is, their influence on the effect of enhancing the airflow along the lower portion of the vehicle 100 and generating a boundary layer of turbulent flow is minimal. As shown in Fig. As shown in Figure 32, the recessed sections 9F preferably have a groove depth d2 that is equal to or less than the projection height h of the raised section 9, so that the raised section 9 is not subdivided midway along its length and the effect of intensifying the airflow along the lower section of the vehicle 100 and generating a boundary layer of turbulent flow can be maintained. For example, the groove depth d2 of the recessed sections 9F is preferably equal to or less than 90% of the projection height h of the raised section 9. Note that the triangular shape of the raised section 9, seen in a cross-section in the transverse direction in Fig. 32 is only one example. Furthermore, the position where the recessed portions 9F are provided is not limited to the upper portion of the raised portion 9 and may be located at a side portion. The opening shape and the depth shape of the recessed portion 9F are not limited to a circular shape and may have various shapes. However, the opening edge and the lower portion are preferably arc-shaped so that there are no elements that tend to generate cracks in the raised portion 9.

[0084] As in Fig. 33, in the pneumatic tire 1 of the present embodiment, the grooves 9E and the depressed portions 9F are preferably formed in the surface of the land portion 9.

[0085] According to the pneumatic tire 1, the rigidity of the land portion 9 is reduced because the grooves 9E and the depressed portion 9F are formed. As a result, a decrease in ride comfort due to the tire side portion S being made into a rigid structure by the land portions 9 can be suppressed. In addition, by forming the grooves 9E and the depressed portion 9F, the mass of the land portion 9 is reduced. As a result, a decrease in uniformity due to the land portions 9 increasing the mass of the tire side portion S can be suppressed.

[0086] Note that the grooves 9E and the recessed portions 9F in Fig. 33 are provided alternately in the direction of survey section 9, but this is not intended as a restriction, and they may be arranged in any suitable mixed manner.

[0087] In the pneumatic tire 1 of the present embodiment, the land portions 9 are preferably arranged at uneven intervals in the tire circumferential direction.

[0088] According to the pneumatic tire 1, the difference in frequency counteracts the periodicity of the raised 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 raised sections 9. As a result, noise (sound pressure level) can be reduced.

[0089] Note that the distances between the raised sections 9, viewed from the side of the pneumatic tire 1, are given as angles between auxiliary lines (not shown) of the raised sections 9, where the auxiliary lines are drawn from the axis of rotation P to the ends 9D of the raised sections 9 in the tire radial direction. The intervals are intervals in the tire circumferential direction between the radially outer raised sections 91, between the radially inner raised sections 92, and between the radially outer raised sections 91 and the radially inner raised sections 92.To cause the spacing between the raised sections 9 to become uneven, various measures can also be taken, such as maintaining the shape (protrusion height h, width W and length L in the direction of travel) of the raised sections 9 and the inclination at which the raised sections 9 intersect the tire circumferential direction and the tire radial direction, while changing the pitch in the tire circumferential direction; changing the shape (protrusion height h, width W and length L in the direction of travel); and changing the inclination at which the raised sections 9 intersect the circumferential direction and the tire radial direction.

[0090] Further, the pneumatic tire 1 of the present embodiment, when mounted on the vehicle, has a prescribed orientation with respect to the vehicle inside / outside, and the tire circumferential direction land portions 9 are preferably formed at least on the tire side portion S corresponding to the vehicle outside.

[0091] In other words, the orientation of the pneumatic tire 1 of the present embodiment when it is mounted on the vehicle 100 (see Fig. 25 and Fig. 26), with respect to the inside and outside of the vehicle 100 in the tire transverse direction. The prescribed orientation is not shown in the drawings, but may be indicated, for example, by indicators provided on the sidewall portions 4. Therefore, the side facing the inside of the vehicle 100 when mounted on the vehicle 100 is the “vehicle inside,” and the side facing 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. 25 and Fig. 26) with respect to the inside and outside of the vehicle 100 in the tire width direction is prescribed. In cases where the pneumatic tire 1 is mounted on a rim, the orientation with respect to the inside and outside of the vehicle is therefore indicated in the tire transverse direction.

[0092] The tire side portion S on the vehicle outer side is exposed to the outside of the tire housing 101 when the pneumatic tire 1 is mounted on the vehicle 100. By providing the raised portions 9 on the tire side portion S on the vehicle outer side, the airflow can be forced toward the vehicle outer side. This can achieve the effect of significantly reducing lift and drag.

[0093] Note that in the pneumatic tire 1 of the embodiment described above, the raised section 9 preferably has a width W in the transverse direction that is in the range of 0.5 mm to 10.0 mm. If the width W of the raised section 9 in the transverse direction is less than the range described above, the area of ​​the raised section 9 that comes into contact with the airflow is small. This makes it difficult to achieve the effect of the raised sections 9 improving the slow airflow. If the width W of the raised section 9 in the transverse direction is greater than the range described above, the area of ​​the raised section 9 that comes into contact with the airflow is large. This causes the raised sections 9 to increase air resistance and tire weight.By appropriately adjusting the width W of the elevation section 9 in the transverse direction, the effect can be achieved that the elevation sections 9 significantly improve the slow airflow.

[0094] Furthermore, the pitch of the raised sections 9 in the circumferential direction of the tire can be the same as or different from the pitch of the lug grooves in the tread section 2 in the circumferential direction. Because the pitch of the raised sections 9 in the circumferential direction differs from the pitch of the lug grooves in the tread section 2 in the circumferential direction, the sound pressure generated by the raised sections 9 and the sound pressure generated by the lug grooves are dispersed and counteract each other due to their different frequencies. As a result, the pattern noise generated by the lug grooves can be reduced. Note that the lug grooves with a different pitch than the raised sections 9 in the circumferential direction include all the lug grooves in the rib-like web sections 23 formed by the main grooves 22 in the transverse direction of the tire.However, in order to achieve the effect of significantly reducing the pattern noise generated by the lug grooves, the pitch spacing of the raised sections 9 in the circumferential direction of the tire is preferably different from the pitch spacing of the laterally outermost lug grooves that are located closest to the raised sections 9. Examples

[0095] For example, tests on lift reduction performance, drag reduction performance, uniformity, durability of the uplift section, ride comfort and noise pressure level reduction performance were carried out on pneumatic tires with different configurations (see Fig. 34).

[0096] In the tests for lift reduction performance and drag reduction performance, a wind tunnel simulation test was carried out using a vehicle model with tire models mounted on a vehicle body model of a motor-driven passenger car.

[0097] The vehicle speed was set to the equivalent of 80 km / h. Using fluid analysis software, the aerodynamic properties (lift reduction performance and drag reduction performance) were obtained using lattice Boltzmann methods and the drag coefficient. The evaluation results are expressed as index values ​​based on the obtained results, with the results of the prior art example defined as the reference value (100). In the evaluation, higher values ​​indicate better lift reduction performance and better drag reduction performance.

[0098] In the uniformity tests, the test tires were inflated to normal internal pressure. The test tires were then measured for radial force variation (LFV) according to the method specified in JASO C607 (Test Procedures for Automobile Tire Uniformity). Evaluations were performed by expressing the measurement results as index values, with the results of the prior art example defined as the reference value (100). Higher scores indicate better uniformity.

[0099] In the tests of the tread section durability performance, using an indoor drum durability test, the test tires were rotated at a speed of 240 km / h for a predetermined period while the condition of the tread sections was monitored. The absence of cracks and failures of the tread sections is required, with "pass" indicating the absence of cracks and failures of the tread sections and "fail" indicating cracks or failures of the tread sections.

[0100] In the ride comfort test, the test tires were mounted on the test vehicle, which was then driven at 50 km / h on a straight test track with 10 mm high undulations. Three members of a test panel then performed a subjective ride comfort test. The evaluation is based on the average of three test results, expressed as index values, with the result of the state-of-the-art example defined as the reference value (100). Higher values ​​indicate better ride comfort.

[0101] In the test for sound pressure level reduction performance, the test tires were mounted on the test vehicle, and the sound pressure level of external noise (the sound pressure level reduction performance) was measured when the test vehicle was driven at a speed equivalent to 80 km / h. The evaluation values ​​are expressed as index values ​​based on the measurement results, with the result of the state-of-the-art example defined as the reference value (100). In the evaluation, higher index values ​​indicate better sound pressure level reduction performance.

[0102] Referring to Fig. 34. The pneumatic tire of the prior art example has a SW / OD ratio of the total width SW to the outer diameter OD of 0.33, the configuration which in Fig. Figure 35 shows a raised section 10, which is provided on the tire sidewall section S. The raised section 10 has a triangular shape when viewed in a cross-section in the transverse direction, as shown in Figure 35. Fig. 14 shown, extends in the radial direction of the tire, has a uniform height and width in the transverse direction, is arranged in a direction which intersects the widest point of the tire H, and is arranged at uniform intervals in the circumferential direction of the tire.

[0103] Furthermore, with reference to Fig. 34. The pneumatic tires of Comparative Example 1 have a SW / OD ratio of the total width SW to the outer diameter OD of 0.24; however, survey sections are provided that are similar to those of the prior art example. The pneumatic tire of Comparative Example 2 exhibits the following: Fig. The configuration shown in section 5 opens and closes the one in Fig. 7 shown elevation section with a triangular shape when viewed in a cross-section in the transverse direction of the elevation section, as in Fig. 14; however, the ratio SW / OD of the total width SW to the outer diameter OD is 0.33.

[0104] Also referring to Fig. 34, the pneumatic tyres of examples 1 to 13 have a ratio SW / OD of the total width SW to the outer diameter OD of 0.24, Fig. 5 and include the radially outer elevation section and the radially inner elevation section, which are shown in Fig. 7, with a triangular shape, as in a cross-section of the Fig. 14 in the transverse direction. The pneumatic tire of Example 14 has the Fig. 8 and includes the radially outer elevation section and the radially inner elevation section, in Fig. 7 shown, with a triangular shape, as in a cross-section in the transverse direction of the Fig. The survey section shown in 14 is considered. The pneumatic tire of example 15 exhibits the [features] in [reference]. Fig. The configuration shown in section 9 includes the radially outer elevation section and the radially inner elevation section. Fig. 7 shown, with a triangular shape, as in a cross-section in the transverse direction of the Fig. The survey section 14 is considered. From other perspectives, the examples are given as appropriate.

[0105] As can be seen from the test results of Fig. As can be seen in Figure 34, the pneumatic tires of the examples exhibit excellent lift reduction performance, drag reduction performance, uniformity, consistency of the raised sections, ride comfort and sound pressure level reduction performance. List of reference symbols 1 pneumatic tire 9 Survey Section 9A Middle Section 9B Top Section 9E groove 9F Deepened Section 91 Radial outer elevation section 92 Radial inner elevation section S Tire sidewall section Sa tire sidewall SW Total width OD outer diameter

Claims

[1] Pneumatic tyre (1), comprising: a plurality of elevation portions (9) extending along a tire side surface (Sa) of a tire side portion (S) in a direction intersecting a tire circumferential direction and a tire radial direction; the plurality of survey sections (9), each of which includes a central portion (9A) in an extending direction, defined as the portion in the range of 25% of the length (L) of the elevation portion (9) in the extending direction from a center (9C) on each side in the extending direction, which includes a highest point (hH) of a projection height (h) from the tire side surface (Sa), and in the direction of extension, peak portions (9B), defined as portions extending from the central portion (9A) on both sides in the direction of extension of 5% of the length (L) of the elevation portion (9) from ends (9D) of the elevation portion (9), and including a lowest point (hL) of a projection height (h) from the tire side surface (Sa), wherein the lowest point (hL) is a point corresponding to 5% of the length (L) from the ends (9D) of the elevation portion (9), and wherein the projection height (h) of the elevation portion (9) at the lowest point (hL) is less than the projection height (h) of the elevation portion (9) at the highest point (hH), the majority of survey sections (9), which include a radially outer elevation portion (91), at least the central portion (9A) being arranged outward from a widest point (H) of the tire in the tire radial direction, and a radially inner elevation portion (92), at least the central portion (9A) being arranged inwardly of the widest point (H) of the tire in the tire radial direction, where a ratio of a total width SW to an outer diameter OD satisfies the relationship SW / OD ≤ 0.3, and where a ratio of an inner diameter RD to the outer diameter OD satisfies the relationship RD / OD ≥ 0.

7. [2] A pneumatic tire according to claim 1, wherein the central portion (9A) and the tip portions (9B) of the radially outer land portion (91) are arranged outward in the tire radial direction from the widest point (H) of the tire. [3] A pneumatic tire according to claim 1 or 2, wherein the central portion (9A) and the tip portions (9B) of the radially inner land portion (92) are arranged inward in the tire radial direction from the widest point (H) of the tire. [4] A pneumatic tire according to any one of claims 1 to 3, wherein a change in the mass of the land portion (9) in the tire circumferential direction per 1 degree in the tire circumferential direction is 0.2 g / degree or less. [5] A pneumatic tire according to any one of claims 1 to 4, wherein the central portion (9A) of the land portion (9) has a projection height (h) in a range of 1 mm to 10 mm. [6] A pneumatic tire according to any one of claims 1 to 5, wherein the land portion (9) protrudes 5 mm or less in a tire transverse direction from a tire cross-sectional width at the widest point (H) of the tire when the pneumatic tire (1) is mounted on a normal rim, inflated to a normal internal pressure, in an unloaded state, and viewed in a meridian cross-section. [7] A pneumatic tire according to any one of claims 1 to 6, wherein a groove (9E) is formed on a surface of the land portion (9). [8] A pneumatic tire according to any one of claims 1 to 7, wherein a depressed portion (9F) is formed on the surface of the land portion (9). [9] A pneumatic tire according to any one of claims 1 to 8, wherein the plurality of land portions (9) are arranged at uneven intervals in the tire circumferential direction. [10] A pneumatic tire according to any one of claims 1 to 9, wherein an orientation with respect to a vehicle inside / outside is prescribed when the pneumatic tire (1) is mounted on a vehicle (100), and the plurality of land portions (9) are formed at least on a tire side portion (S) corresponding to a vehicle outside.

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