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; where the majority of survey sections (9) each include the following a section (9A) in the middle of a direction of travel, which includes a highest point (hH) of a projection height (h) from the tire sidewall (Sa), and in the direction of travel peak sections (9B) on each side of the middle section (9A), which include a lowest point (hL) of a projection height (h) from the tire sidewall (Sa), wherein at least the intermediate section (9A) is arranged only inwards from a widest point (H) of the tire in the tire radial direction; wherein a ratio of a total width SW to a The outer diameter OD satisfies the relationship SW / OD ≤ 0.3. wherein a ratio of an inner diameter RD to the outer diameter OD satisfies the relationship RD / OD ≥ 0.7, and wherein a change in the mass of the raised section (9) in the tire circumferential direction per 1 degree in the tire circumferential direction is 0.1 g / degree or less.

Description

Technical field

[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] Furthermore, JP 2013-071650 A describes a technology in which a plurality of raised sections are arranged on at least one tire sidewall section in an inner area in the tire radial direction. The raised sections are formed as ridges running longitudinally in a predetermined direction. JP 2013-071650 A describes how the airflow is swirled by the raised sections, thereby creating a boundary layer of turbulent flow in the area encompassing the raised sections. This further suppresses the spreading of the flowing air. As a result, the vehicle's drag is reduced, and fuel economy is improved.

[0004] 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).

[0005] US 2005 / 0 081 975 A1 shows a pneumatic tire with decorative sections and raised sections. A connecting section between the decorative section and the raised sections is higher than the base of the decorative section to prevent stress concentrations between the raised sections and the decorative sections.

[0006] EP 1 925 468 A1 discloses a pneumatic tire with a concave-convex section for generating turbulence, consisting of grooves and ribs along a tire sidewall. This concave-convex section contributes to a temperature reduction on the tire sidewall.

[0007] JP 2001-287512 A shows a pneumatic tire with a plurality of decorative sections along one sidewall of the tire. The decorative sections are designed to fulfill their primary function (identification, visibility, etc.) without significantly contributing to air resistance.

[0008] DE 11 2016 001 632 T5 discloses a pneumatic tire that can provide reduced lift and air resistance while maintaining good uniformity. The pneumatic tire comprises a plurality of raised sections that run along a tire sidewall in a direction that intersects the tire's circumferential and radial directions. Brief description of the invention: Technical problem

[0009] However, the pneumatic tires described in JP 2013-018474 A and JP 2013-071650 A 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.

[0010] In view of this, one objective of the present invention is to create a pneumatic tire that can provide reduced lift and air resistance while maintaining good uniformity. Solution to the problem

[0011] To solve the problems and achieve the objectives described above, a pneumatic tire of 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 that encompasses the highest point of a protrusion height from the tire sidewall, and pointed sections on both sides of the central section in the direction of travel that encompass the lowest point of the protrusion height from the tire sidewall; wherein at least the central section is arranged in the tire radial direction only inwards from a widest point of the tire; and a ratio of a total width SW to an outer diameter OD satisfies the relationship SW / OD ≤ 0.3.In this case, a ratio of an inner diameter RD to the outer diameter OD satisfies the relationship RD / OD ≥ 0.7, and a change in the mass of the raised section in the tire circumferential direction per 1 degree in the tire circumferential direction is 0.1 g / degree or less.

[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 spread of the airflow is suppressed, which reduces the air resistance of the pneumatic tire. This reduction in air resistance leads to improved fuel consumption figures for the vehicle.

[0013] Furthermore, according to the pneumatic tire design, the central section of the raised section, in the direction intersecting the tire's circumferential and radial directions, encompasses the highest point of the raised section height from the tire sidewall. The tip sections, located on either side of the central section in the same direction, each encompass the lowest point of the raised section height from the tire sidewall. Consequently, the mass of the raised section is lower at the tip sections. This prevents a sudden change in mass from the tire sidewall in the area near the tip sections of the raised section, thus improving uniformity in the tire's circumferential direction.

[0014] Furthermore, according to the pneumatic tire design, the central section of the raised section, which includes the highest point of the ridge height, is located only inwards from the widest point of the tire when viewed radially. Thus, the air resistance is reduced at the widest point of the tire, where the pneumatic tire is widest in the lateral direction, which is also where the air resistance is high. Consequently, 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 air resistance 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 raised section are arranged inwards in the tire radial direction 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 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 0.1 g / degree or less.

[0020] 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.

[0021] 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.

[0022] 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.

[0023] 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.

[0024] 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.

[0025] In the pneumatic tire according to another embodiment of the present invention, a groove is formed on a surface of the raised section.

[0026] 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.

[0027] In the pneumatic tire according to another embodiment of the present invention, a recessed section is formed on a surface of the raised section.

[0028] 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.

[0029] In the pneumatic tire according to another embodiment of the present invention, the majority of raised sections are arranged at uneven intervals in the circumferential direction of the tire.

[0030] According to the pneumatic tire, the difference in frequency, by counteracting the periodicity of the raised sections in the tire's circumferential direction with respect to the airflow along the tire's sidewall, causes the sound pressure generated by the raised sections to be distributed and balanced. As a result, noise can be reduced.

[0031] 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 majority of raised sections are formed at least on one tire side section that corresponds to a vehicle outside.

[0032] 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.

[0033] Advantageous effects of the invention: The pneumatic tire according to an embodiment of the present invention can provide reduced lift and air resistance while maintaining good uniformity. 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 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 another example 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 cross-sectional view of a survey section in the transverse direction. 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. Figure 17 is a cross-sectional view of a survey section in the transverse direction. Fig. Figure 18 is a cross-sectional view of a survey section in the transverse direction. Fig. Figure 19 is a cross-sectional view of a survey section in the transverse direction. Fig. Figure 20 is a cross-sectional view of a survey section in the transverse direction. Fig. Figure 21 is a cross-sectional view of a survey section in the transverse direction. Fig. Figure 22 is a cross-sectional view of a survey section in the transverse direction. Fig. Figure 23 is a cross-sectional view of a survey section in the transverse direction. Fig. Figure 24 is a sketch illustrating the function of a pneumatic tire according to an embodiment of the present invention. Fig. Figure 25 is a sketch illustrating the function of a pneumatic tire according to an embodiment of the present invention. Fig. Figure 26 is a meridian cross-sectional view of a section of a pneumatic tire according to an embodiment of the present invention. Fig. Figure 27 is an enlarged view of a raised section in which grooves are formed, as seen from the side of a pneumatic tire. Fig. 28 is a cross-sectional view along a line AA of Fig. 27. Fig. Figure 29 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 30 is an enlarged view of an elevation section in which depressions are formed, seen from the side of a pneumatic tire. Fig. 31 is a cross-sectional view along a line BB of Fig. 30. Fig. Figure 32 is an enlarged view of a raised section in which grooves and recessed sections are formed, as seen from the side of a pneumatic tire. Fig. Figure 33 is a table showing results of performance tests of pneumatic tires according to examples of the present invention. Fig. Figure 34 is a side view of a section of a pneumatic tire according to a prior art example. Description of embodiments

[0034] Embodiments of the present invention are explained in detail below with reference to the drawings.

[0035] 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.

[0036] 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 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. “Circular direction” denotes the circumferential direction whose central axis is the axis of rotation P. “Transverse direction” also denotes the direction that is parallel to the axis of rotation P. “Inward in the tire transverse direction” denotes the direction that leads toward a tire equatorial plane CL (a tire equator line) in the tire transverse direction. “Outward in the tire transverse direction” denotes the direction that leads away from the tire equatorial plane CL in the tire transverse direction. “Tire equatorial plane CL” denotes a plane that is perpendicular to the axis of rotation P of the pneumatic tire 1 and that passes through the center of one tire width of the pneumatic tire 1.“Tire width” is the width in the transverse direction of the tire between components located outwards in the transverse direction, or in other words, the distance between the components furthest from the equatorial plane CL of the tire in the transverse direction. “Tire equator line” refers to the line along the circumferential direction of the pneumatic tire 1 that lies on the equatorial plane CL of the tire. In the present embodiment, the tire equator line and the equatorial plane of the tire are both designated by the reference numeral CL.

[0037] 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.

[0038] The tread section 2 is made of rubber material (tread rubber) and is exposed on the outermost side of the pneumatic tire 1 in the radial direction, and its surface forms the tread pattern of the pneumatic tire 1. A tread surface 21 is formed on an outer circumferential surface of the tread section 2, or 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 (four in the present embodiment) of main grooves 22, which are straight main grooves that run parallel to the tire equator line CL in the circumferential direction. Furthermore, the multiple main grooves 22 form a plurality of rib-like rib sections 23 in the tread surface 21, which run along the circumferential direction and parallel to the tire equator line CL.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.

[0039] The shoulder sections 3 are areas of the tread section 2 that are arranged on both sides in the transverse direction of the tire. Additionally, the sidewall sections 4 are exposed at the outermost sides 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 shape. The bead filler 52 is a rubber material arranged in a space formed by folding over one end of the carcass layer 6 in the transverse direction of the tire at the position of the bead core 51.

[0040] 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.

[0041] The belt layer 7 has a multi-layered structure, with at least two belts 71, 72 superimposed. 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 and 72 enclose a plurality of cord threads (not shown) which are oriented at a predetermined angle (e.g., from 20° to 30°) to the tire circumferential direction and coated with a rubber layer. The cord threads are made of steel or organic fibers (polyester, rayon, nylon, or the like). Furthermore, the belts 71 and 72 overlap each other and are arranged such that the direction of the cord threads of the respective belts intersects.

[0042] 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-like strip material (e.g., 10 mm wide) wound in the tire's circumferential direction.

[0043] Fig. 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. 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, seen from the side of the pneumatic tire. Fig. Figure 7 is a side view of a survey section. Fig. Figures 8 to 11 are side views of other examples of a pneumatic tire according to the present embodiment. Fig. Figures 12 to 23 are cross-sectional views of a survey section in the transverse direction. Fig. 24 and Fig. Figure 25 are explanatory diagrams of the function of a pneumatic tire according to the present embodiment. Fig. Figure 26 is a meridian cross-sectional view of a section of the pneumatic tire according to the present embodiment. Fig. Figure 27 is an enlarged view of a raised section in which grooves are formed, as seen from the side of a pneumatic tire. Fig. 28 is a cross-sectional view along a line AA of Fig. 27. Fig. Figure 29 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 30 is an enlarged view of an elevation section in which depressions are formed, seen from the side of a pneumatic tire. Fig. 31 is a cross-sectional view along a line BB of Fig. 30. Fig. Figure 32 is an enlarged view of a raised section in which grooves and recessed sections are formed, as seen from the side of a pneumatic tire.

[0044] 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.

[0045] 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 whether 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.

[0046] 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.

[0047] 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.

[0048] In the case of a pneumatic tire 1 of the present embodiment, as 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.

[0049] 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.

[0050] In the pneumatic tire 1 of the present embodiment, as in Fig. As shown in Figures 5 to 7, a raised section 9 is provided on at least one tire sidewall section S. This raised section projects outwards over a side surface Sa that corresponds to the profile of the surface of the tire sidewall section S. The raised section 9 is made of a rubber material (the same rubber material that forms the tire sidewall section S or a different rubber material) and is designed as a comb extending along the tire sidewall surface Sa of the tire sidewall section S in a direction that intersects the tire's circumferential and radial directions. In the present embodiment, the raised section 9, as shown in the drawings, curves into a C-shape when viewed from the side of the pneumatic tire 1.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.

[0051] 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.

[0052] The middle section 9A also includes a highest point hH, where the protrusion height h from the tire sidewall surface Sa is greatest. The tip section 9B also includes a lowest point hL, where the protrusion height h from the tire sidewall surface Sa is 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 peak sections 9B can have an elevation h that gradually decreases from the middle section 9A onwards.

[0053] As in Fig. As shown in Figure 5, the raised section 9 is located in the area of ​​the tire sidewall section S, inwards in the tire radial direction from a widest point of the tire H. A plurality of raised sections 9 are arranged at predetermined intervals in the tire circumferential direction.

[0054] As in Fig. As shown in Figure 8, the raised section 9 can extend partially outwards in the tire radial direction beyond the widest point of the tire H. In such a design, the central section 9A is arranged inwards in the tire radial direction from the widest point of the tire H, and at least one of the tip sections 9B (or the area of ​​5% of the length L from the end 9D) extends in the tire radial direction beyond the widest point of the tire H. Fig. In the 8th embodiment, all raised sections 9 extend partially beyond the widest point of the tire H in the tire radial direction, but in another embodiment, this may only apply to a portion of the raised sections 9. Therefore, the raised sections 9 in the area of ​​the tire sidewall section S are arranged such that the main section (the central section 9A) is positioned inwards in the tire radial direction from the widest point of the tire H.

[0055] It should be noted that for tires equipped with a rim protection strip, the raised sections 9 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 rim protection strip projection, or a configuration in which an inner end section in the tire radial direction reaches the height of the rim protection strip.

[0056] As in Fig. 5, Fig. 9, Fig. 10 and Fig. As shown in Figure 11, the number of survey sections 9, arranged in the direction of the tire circumference, is not limited to a specific number. As shown in Fig. 10 and Fig. As shown in Figure 11, the survey sections 9 can also vary in inclination in the direction of travel with respect to the tire circumferential direction and the tire radial direction.

[0057] The in Fig. Section 9 of the survey, as depicted in Figure 12, has a four-sided cross-sectional shape in the transverse direction, which is perpendicular to the direction of travel of section 9. The section shown in Figure 12 has a four-sided cross-sectional shape in the transverse direction, which is perpendicular to the direction of travel of section 9. Fig. Section 9 of the survey, shown in Figure 13, has a triangular cross-sectional shape in the transverse direction. The section shown in Figure 13 has a triangular cross-sectional shape in the transverse direction. Fig. Section 9 of the survey shown in Figure 14 has a trapezoidal cross-sectional shape in the transverse direction.

[0058] 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 elevation section 9 shown in Figure 15 has a semicircular cross-sectional shape in the transverse direction. Although not shown in the drawings, the cross-sectional shape of elevation section 9 in the transverse direction can also be a semi-oval shape, a semi-elliptical shape, or any other arc shape.

[0059] 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 16 has a cross-sectional shape in the transverse direction that is a four-sided shape with rounded corners. The section shown in Figure 16 has a cross-sectional shape that is four-sided with rounded corners. Fig. Section 9 of the survey shown in Figure 17 has a cross-sectional shape in the transverse direction that is triangular with rounded corners. Furthermore, as shown in the Fig. Figures 16 to 18 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.

[0060] Furthermore, the cross-sectional shape of survey section 9 can be a combination of different shapes in the transverse direction. The one in Fig. Section 9 of the survey depicted in 19 includes a four-sided upper section characterized by a plurality of triangular shapes (two in Fig. 19) takes on a zigzag shape. The one in Fig. Section 9 of the survey, as depicted in Figure 20, includes a four-sided upper section that tapers to a point through a single triangular shape. The section shown in Figure 20 includes a four-sided upper section that tapers to a point. Fig. Section 9 of the survey, as depicted in Figure 21, includes a four-sided upper section, which is designed as a four-sided depression. The section shown in Figure 21 includes a four-sided upper section, which is designed as a four-sided depression. Fig. The elevation section 9 shown in Figure 22 includes a four-sided upper section, which is designed as a four-sided depression, with the projection height differing on each side of the depression. The section shown in Figure 22 includes a four-sided upper section, which is designed as a four-sided depression, with the projection height differing on each side of the depression. Fig. Section 9 of the survey, as depicted in Figure 23, includes a four-sided platform section 9a, which is designed to project from the tire sidewall section S. A plurality of four-sided shapes (two in Fig. 23) as described above. Although not shown in the drawings, the cross-sectional shape of the raised section 9 in the transverse direction may also include a four-sided upper section with a wave-like shape or have another shape.

[0061] 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.

[0062] The function of the pneumatic tire 1 is in Fig. Figure 24 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 creating drag.

[0063] 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 25, this effect can be obtained by adjusting the inclination of the raised sections 9 with respect to the tire circumferential direction and the tire radial direction. Fig. 24 is reversed.

[0064] 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.

[0065] Furthermore, according to the pneumatic tire 1 of the present embodiment, the central section 9A in the raised section 9, which includes the highest point hH of the projection height h, is located only inwards from the widest point of the tire H when viewed in the tire's radial direction. Thus, the air resistance at the widest point of the tire H, where the pneumatic tire 1 is widest in the tire's transverse direction, is reduced, which also results in a high air resistance there. Consequently, the air resistance is further reduced.

[0066] 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, 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 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 (the upper position on the tire sidewall section S when the tire is mounted on a vehicle) and the air, the pneumatic tire 1 of the present embodiment has 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.

[0067] Thus, the pneumatic tire 1 of the present embodiment can provide reduced lift and air resistance while maintaining good uniformity.

[0068] In the pneumatic tire 1 of the present embodiment, the central section 9A and the tip sections 9B of the raised section 9 are preferably arranged in the tire radial direction inwards from the widest point of the tire H.

[0069] 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.

[0070] Furthermore, as in Fig. 5 shown, in the pneumatic tire 1 of the present embodiment according to the invention the change in the mass of the raised section 9 in the tire circumferential direction per 1 degree in the tire circumferential direction, subdivided by means of lines extending from the axis of rotation P in the tire radial direction, 0.1 g / degree or less.

[0071] 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.

[0072] 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.

[0073] 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.

[0074] 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. 26 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.

[0075] 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.

[0076] As in Fig. As illustrated in Figures 27 to 29, the pneumatic tire 1 of the present embodiment has a groove 9E which is preferably formed in the surface of the raised section 9.

[0077] According to the pneumatic tire 1, the stiffness of the raised section 9 is reduced because of the groove 9E. Consequently, a decrease in ride comfort due to the raised sections 9 making the tire sidewall section S a stiffer structure can be suppressed. Furthermore, the mass of the raised section 9 is reduced by the groove 9E. Consequently, a decrease in uniformity due to the raised sections 9 increasing the mass of the tire sidewall section S can be suppressed.

[0078] Note that a majority of the grooves 9E are provided at predetermined intervals with respect to the length L, as shown in Fig. 27 is shown, such that they intersect the direction of travel of the raised section 9. An angle θ at which the grooves 9E intersect the direction of travel of the raised section 9 is not specifically specified. However, the grooves 9E preferably have the same angle θ, so that an extreme change in the mass of the raised section 9 in the direction of travel is suppressed. As in Fig. As shown in Figure 29, 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. As shown in Figure 28, the grooves 9E preferably have a groove depth d1 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 d1 of the grooves 9E 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. 28 is just one example.

[0079] As in Fig. 30 and Fig. As shown in Figure 31, the pneumatic tire 1 of the present embodiment has a recessed section 9F, which is preferably formed in the surface of the raised section 9.

[0080] 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.

[0081] Note that a majority of the deepened sections 9F are provided at predetermined intervals in the direction of survey section 9, as shown in Fig. Figure 30 is shown. In embodiments in which the width W of the raised section 9 changes in the direction of travel, the recessed sections 9F preferably change their size according to the change in width W, so that an extreme change in the mass of the raised section 9 in the direction of travel is suppressed. The recessed sections 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 the intensification of 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. As shown in Figure 31, 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. Figure 31 is just one example. Furthermore, the position where the recessed sections 9F are provided is not limited to the upper section of the raised section 9 and can be located on a side section. The opening shape and the depth shape of the recessed section 9F are not limited to a circular shape and can have various forms. However, the opening edge and the lower section are preferably arcuate, so that they are not elements that tend to generate cracks in the raised section 9.

[0082] As in Fig. As shown in Figure 32, the grooves 9E and the recessed sections 9F in the pneumatic tire 1 of the present embodiment are preferably formed in the surface of the raised section 9.

[0083] According to the pneumatic tire 1, the stiffness of the raised section 9 is reduced because of the grooves 9E and the recessed section 9F. Consequently, a decrease in ride comfort due to the raised sections 9 making the tire sidewall section S a stiffer structure can be mitigated. Furthermore, the mass of the raised section 9 is reduced by the grooves 9E and the recessed section 9F. As a result, a decrease in uniformity due to the increased mass of the tire sidewall section S caused by the raised sections 9 can be mitigated.

[0084] Note that the grooves 9E and the recessed sections 9F in Fig. 32 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.

[0085] In the pneumatic tire 1 of the present embodiment, the raised sections 9 are preferably arranged at uneven intervals in the tire circumferential direction.

[0086] 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.

[0087] Note that the distances of 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.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.

[0088] Furthermore, when the pneumatic tire 1 of the present embodiment is mounted on the vehicle, it has a prescribed orientation with respect to the inside / outside of the vehicle, and the raised sections 9 extending in the circumferential direction of the tire are preferably formed at least on the tire sidewall section S, which corresponds to the outside of the vehicle.

[0089] In other words, the orientation of the pneumatic tire 1 of the present embodiment when it is mounted on the vehicle 100 (see Fig. 24 and Fig. 25), with respect to the inside and outside of the vehicle 100 in the tire's transverse direction. The prescribed orientation is not shown in the drawings but can be indicated, for example, by markings provided on the sidewall sections 4. Therefore, the side facing the inside of the vehicle 100 when mounted is the "inside of the vehicle," and the side facing the outside of the vehicle 100 is the "outside of the vehicle." It should be noted that the markings of the inside and outside of the vehicle are not limited to cases involving mounting 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. 24 and Fig. 25) with respect to the inside and outside of the vehicle, 100 is prescribed in the tire width direction. 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 prescribed in the tire transverse direction.

[0090] The tire sidewall section S on the outside of the vehicle is released outwards by the tire housing 101 when the pneumatic tire 1 is mounted on the vehicle 100. Because the raised sections 9 are provided on the tire sidewall section S on the outside of the vehicle, the airflow can be forced towards the outside of the vehicle. This results in a significant reduction in lift and air resistance.

[0091] 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.

[0092] 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 of the tire. 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 of the tire, 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 of the tire include all the lug grooves in the rib-like web sections 23 formed in the transverse direction of the tire by the main grooves 22.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

[0093] 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. 33).

[0094] The lift reduction performance and drag reduction performance test involved a wind tunnel simulation test using a vehicle model with tire models mounted on a vehicle body model of a motor-driven passenger car.

[0095] 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.

[0096] 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). In the evaluation, higher scores indicate better uniformity.

[0097] In the tests of the rib 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 ribs was monitored. The absence of cracks and failures of the ribs is required, with "pass" indicating the absence of cracks and failures of the ribs, and "fail" indicating cracks or failures of the ribs.

[0098] 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.

[0099] 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.

[0100] Referring to Fig. In the prior art example, the pneumatic tire has a SW / OD ratio of 0.33, the configuration which is described in Fig. Figure 34 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 34. Fig. 13, 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.

[0101] Furthermore, with reference to Fig. 33. The pneumatic tire of Comparative Example 1 has 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. The survey section shown in section 7 has a triangular shape when viewed in a cross-section in the transverse direction of the survey section, as shown in Fig. Figure 13 shows the ratio of SW / OD of the total width SW to the outer diameter OD is 0.33.

[0102] Furthermore, with reference to Fig. 33 The pneumatic tires of examples 1 to 11 have a SW / OD ratio of the total width SW to the outer diameter OD of 0.24, which in Fig. 5 configurations shown and close the one in Fig. The survey section shown in section 7 has a triangular shape, as in a cross-section of the area shown in Fig. The section of the survey shown in 13 is viewed in the transverse direction. The pneumatic tire of example 12 exhibits the [features shown in] Fig. The configuration shown in section 8 is displayed and includes the one shown in the diagram. Fig. The survey section shown in section 7 has a triangular shape when viewed in a cross-section in the transverse direction of the survey section, as shown in Fig. 13 are shown. From other perspectives, the examples are given as appropriate.

[0103] As can be seen from the test results of Fig. As can be seen in Figure 33, the pneumatic tires of the examples exhibit excellent lift reduction performance, drag reduction performance, uniformity, durability 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 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; wherein the plurality of survey sections (9) each include the following a central portion (9A) in a direction of extension, which includes a highest point (hH) of a projection height (h) from the tire side surface (Sa), and in the direction of extension, tip portions (9B) on each side of the central portion (9A) which enclose a lowest point (hL) of a projection height (h) from the tire side surface (Sa), wherein at least the intermediate portion (9A) is arranged only inwardly of a widest point (H) of the tire in the tire radial direction; wherein a ratio of a total width SW to a Outer diameter OD satisfies the relationship SW / OD ≤ 0.3, wherein a ratio of an inner diameter RD to the outer diameter OD satisfies the relationship RD / OD ≥ 0.7, and 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 0.1 g / degree or less. [2] A pneumatic tire according to claim 1, wherein the central portion (9A) and the tip portions (9B) of the land portion (9) are arranged inward 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) of the land portion (9) has a projection height (h) in a range of 1 mm to 10 mm. [4] A pneumatic tire according to any one of claims 1 to 3, 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. [5] A pneumatic tire according to any one of claims 1 to 4, wherein a groove (9E) is formed on a surface of the land portion (9). [6] A pneumatic tire according to any one of claims 1 to 5, wherein a depressed portion (9F) is formed on the surface of the land portion (9). [7] A pneumatic tire according to any one of claims 1 to 6, wherein the plurality of land portions (9) are arranged at uneven intervals in the tire circumferential direction. [8] A pneumatic tire according to any one of claims 1 to 7, 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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