pneumatic tires

Abstract

An object of the present invention is to provide a pneumatic tire with reduced rolling resistance under normal load conditions and improved dry braking performance. In a condition where the pneumatic tire is mounted on a normal rim and inflated to 5% of a predetermined internal pressure, where the tread width W is and the overall tire width SW is in a tire meridian cross-sectional view, a relationship of 0.80 ≤ TW / SW ≤ 0.95 is satisfied, and where the ground contact width at a load of 100% of the maximum load capacity is CW100 and the ground contact width at a load of 70% of the maximum load capacity is CW70, a relationship of 1.04 ≤ CW100 / CW70 ≤ 1.15 is satisfied.

Description

Technical field

[0001] The present invention relates to a pneumatic tire with reduced rolling resistance in a normal load condition and improved dry braking performance. State of the art

[0002] Various techniques have been proposed to reduce rolling resistance, which is an important factor for lower fuel consumption and the like.

[0003] For example, a technique was proposed for reducing the thickness of a rubber component forming a shoulder area to achieve a lower weight and thus reduce rolling resistance (Patent Document 1). Furthermore, a technique was proposed in which the ratio TR3 / TR2 of the radius of curvature TR3 at 300 kPa – the high internal pressure setting – to the radius of curvature TR2 at 230 kPa – the internal pressure approaching normal internal pressure – and the specified air pressure of the tire for a passenger car is set to 1.10 to 1.50, so that the central tread area TC bulges in a well-balanced manner to reduce rolling resistance, even when the tire is inflated to a high internal pressure (Patent Document 2). Bibliography of patent documents Patent document 1: JP 5469692 B Patent document 2: JP 5952587 B Brief description of the invention: Technical problem

[0004] In recent years there has been an increasing demand for faster and more accurate stopping under braking load conditions, as well as reduced rolling resistance under normal load and lower fuel consumption performance.

[0005] As in the case of the technology described in Patent Document 1, from this perspective, reducing the thickness of the rubber forming the shoulder area ensures sufficient ground contact. However, this creates the risk that sufficient frictional force will not be achieved under braking load. If the TR3 / TR2 ratio is set to 1.10 to 1.50, the tread center area TC, as in the technology described in Patent Document 2, bulges excessively when inflated to the specified air pressure or higher. This creates the risk that sufficient ground contact width is not guaranteed and that insufficient frictional force is not achieved under braking load. As described above, Patent Documents 1 and 2 offer potential for improvement in increasing frictional force under braking load and in improving dry braking performance.

[0006] In light of the foregoing, the purpose of the present invention is to provide a pneumatic tire with reduced rolling resistance under normal load conditions and improved dry braking performance. Solution to the problem

[0007] The pneumatic tire according to the invention comprises a pair of left and right bead sections; sidewall sections connected to an outer surface in the radial direction of the bead sections; a tread section extending between the sidewall sections; a carcass, including at least one carcass ply extending in a torus shape between the pair of left and right bead sections; a belt, including at least one belt layer arranged on an outer surface in a tire radial direction of the carcass and including cord threads; and a tread rubber arranged on an outer surface in the tire radial direction of the belt and forming a section of the tread section, in a state in which the pneumatic tire is mounted on a normal rim and inflated to 5% of a predetermined internal pressure, with a tread width W and a total tire width SWin a tire meridian cross-section view, a relationship of 0.80 ≤ TW / SW ≤ 0.95 is satisfied, and if a ground contact width at a load of 100% of a maximum load capacity is CW100 and a ground contact width at a load of 70% of the maximum load capacity is CW70, a relationship of 1.04 ≤ CW100 / CW70 ≤ 1.15 is satisfied. Advantageous effects of the invention

[0008] In the pneumatic tire according to one embodiment of the present invention, improvements are made to the ratio of the tread width to the overall tire width and to the ratio of the ground contact width under braking load to the ground contact width under normal load. As a result, according to the pneumatic tire of one embodiment of the present invention, it is possible to improve the rolling resistance under normal load and the dry braking performance in a balanced manner. List of characters Fig.Figure 1 is a meridian cross-sectional view illustrating a pneumatic tire according to an embodiment of the present invention. Fig. 2 is a tire meridian cross-sectional view of the in Fig. Figure 1 illustrates the pneumatic tire of the present embodiment, which illustrates only one side in the tire width direction from an equatorial plane of the tire CL, extending from a sidewall section to a tread section. Fig. 3 is a tire meridian cross-sectional view of the in Fig. Figure 1 illustrates the pneumatic tire of the present embodiment, which illustrates only one side in the tire width direction from the equatorial plane of the tire CL, extending from a tread section to a shoulder section. Fig. 4 is a tire meridian cross-sectional view of the in Fig.Figure 1 illustrates the pneumatic tire of the present embodiment, which illustrates only one side in the tire width direction from the equatorial plane of the tire CL, extending from the tread section to the shoulder section. Fig. 5 is a tire meridian cross-sectional view of the in Fig. Figure 1 illustrates the pneumatic tire of the present embodiment, which illustrates only one side in the tire width direction from the equatorial plane of the tire CL, extending from the bead section to the tread section. Fig. 6 is a tire meridian cross-sectional view of the in Fig. Figure 1 illustrates the pneumatic tire of the present embodiment, which illustrates only one side in the tire width direction from the equatorial plane of the tire CL, extending from the tread section to the shoulder section. Description of embodiments

[0009] Pneumatic tires according to embodiments (including the basic embodiments and additional embodiments 1 to 8) of the present invention are described below with reference to the drawings. It should be noted that the present invention is not limited to these embodiments. Components of the embodiments include components that are essentially identical or that can be substituted or easily devised by a person skilled in the art. Furthermore, various modes described in this embodiment can be combined as desired, within the scope of obviousness to a person skilled in the art. Basic embodiment

[0010] The following is a description of the basic mode of the pneumatic tire according to an embodiment of the present invention. Herein, "tire radial direction" refers to the direction perpendicular to the axis of rotation of the pneumatic tire. "Inward in the tire radial direction" refers to the direction facing the axis of rotation in the tire radial direction. "Outward in the tire radial direction" refers to the direction facing away from the axis of rotation in the tire radial direction. "Circular direction" refers to the circumferential direction, with the central axis being the axis of rotation.Furthermore, "tire width direction" refers to a direction parallel to the axis of rotation; "inside in tire width direction" refers to a side facing the tire's equatorial plane (tire equator line) in the tire width direction; and "outside in tire width direction" refers to a side farther from the tire's equatorial plane in the tire width direction. It should be noted that "tire equatorial plane" refers to the plane perpendicular to the tire's axis of rotation that passes through the center of the tire's width.

[0011] Fig. Figure 1 is a meridian cross-sectional view illustrating a pneumatic tire according to an embodiment of the present invention. A pneumatic tire 10 , which is illustrated in the same drawing, closes a pair of left and right bead sections 12 , side wall sections 14, which have outer surfaces in the radial direction of the bead sections 12 are connected, and a tread section 16 , which is located between the side wall sections 14 extends, one.

[0012] The in Fig. 1 shown pneumatic tire 10 closes a carcass 22 one that includes at least one carcass ply (one carcass ply is shown in the same drawing), which is in a torus shape between the pair of left and right bead sections 12 and 12 extends, a belt 24 , which includes at least one belt layer 24a until 24c (three layers are shown in the same drawing) includes the outer layer in the tire radial direction of the carcass. 22 is arranged and includes cord threads, and a tread rubber 26 , which is on the outside in the direction of the tire width of the belt 24is arranged and forms a section of the tread area 16 educates.

[0013] Under the assumptions described above, the pneumatic tire meets 10 in a state in which the pneumatic tire 10 mounted on a normal rim and inflated to 5% of a specified internal pressure, as in Fig. Figure 1 shows a relationship of 0.80 ≤ TW / SW ≤ 0.95 when the tread width TW is and the total tire width SW in a tire meridian cross-section view, and a relationship of 1.04 ≤ CW100 / CW70 ≤ 1.15 is satisfied if the ground contact width (a dimension in the tire width direction of the ground contact surface) is CW100 at a load of 100% of the maximum load capacity and CW70 at a load of 70% of the maximum load capacity.

[0014] Here, "specified rim" refers to an "applicable rim" as defined by the Japan Automobile Tyre Manufacturers Association (JATMA), a "design rim" as defined by the Tire and Rim Association (TRA), and a "measuring rim" as defined by the European Tyre and Rim Technical Organisation (ETRTO). Furthermore, "specified internal pressure" refers to a "maximum air pressure" as defined by JATMA, the maximum value in "TIRE LOAD LIMITS AT VARIOUS COLD INFLATION PRESSURES" as defined by the TRA, and "INFLATION PRESSURES" as defined by the ETRTO.Furthermore, “maximum load capacity” refers to the “maximum load capacity” as defined by JATMA, the maximum value in “TIRE LOAD LIMITS AT VARIOUS COLD INFLATION PRESSURES” as defined by TRA, or “LOAD CAPACITY” as defined by ETRTO. Effects

[0015] Generally, under normal load conditions, it is desirable to reduce the ground contact area and thus the rolling resistance in order to decrease fuel consumption. Conversely, under braking load conditions, it is desirable to increase the ground contact area and improve braking performance to achieve reliable stopping.

[0016] In the present embodiment, improvements are made to the ratio between the tread width TW and the overall tire width SWand added to the ratio of the ground contact width CW100 in the braking load condition to the ground contact width CW70 in the normal load condition.

[0017] By adjusting the ratio TW / SW the tread width TW to the total tire width SW A sufficient ground contact width and a sufficient ground contact area of ​​the so-called shoulder section can be achieved at 0.80 or more. 18 at or near the boundary between the side wall section 14 and the tread section 16 This can be ensured, and the frictional force under braking load can be increased (Effect 1). In contrast, by adjusting the ratio TW / SW the tread width TW to the total tire width SW ground contact pressure at the shoulder section is reduced to 0.95 or less. 18not excessively, and the rolling resistance under normal load conditions can be reduced (Effect 2).

[0018] It should be noted that the ratio TW / SW the tread width TW to the total tire width SW preferably set to 0.83 or more and 0.92 or less, and more preferably to 0.85 or more and 0.90 or less.

[0019] By adjusting the ratio CW100 / CW70 of the ground contact width (ground contact width under braking load) CW100 at 100% of the maximum load capacity to the ground contact width (ground contact width under normal load) CW70 at 70% of the maximum load capacity to 1.04 or more, sufficient ground contact width under braking load can be ensured, thus increasing the frictional force under braking load (Effect 3). Conversely, by adjusting the ratio CW100 / CW70 to 1.15 or less, the rolling resistance under braking load can be reduced without excessively increasing the ground contact length (a dimension in the tire's circumferential direction under ground contact) under braking load (Effect 4).

[0020] It should be noted that the ratio CW100 / CE70 of the ground contact width CW100 to the ground contact width CW70 is preferably set to 1.06 or more and 1.13 or less, and more preferably to 1.08 or more and 1.11 or less.

[0021] As described above, in the case of the pneumatic tire according to the present embodiment, improvements to the ratio TW / SW and added to the ratio CW100 / CW70, it is possible to reduce the rolling resistance in the normal load condition due to effect 2, and it is possible to increase the frictional force in the braking load condition and thus the dry braking performance due to the combination of effects 1, 3 and 4.

[0022] The pneumatic tire according to the present embodiment is obtained by various general manufacturing processes, in other words, a step of mixing tire materials, a step of processing the tire materials, a step of forming a tire blank, a vulcanization step, an inspection step after vulcanization, and the like. In the manufacture of the pneumatic tire according to the present embodiment, for example, raised sections and recessed sections corresponding to grooves and raised sections are formed. Fig. The running surface section shown in 1 is formed in the inner wall of a vulcanization mold, and vulcanization is carried out using this mold. Additional embodiments

[0023] The following are descriptions of the additional embodiments 1 to 9, which can optionally be implemented instead of the basic embodiment of the pneumatic tire according to the present invention described above. Additional embodiment 1

[0024] Fig. 2 is a tire meridian cross-sectional view of the in Fig. Figure 1 of the pneumatic tire of the present embodiment, which illustrates only one side in the tire width direction from the equatorial plane of the tire CL, which is from the sidewall section 14 to the tread section 16 proceeds. In its basic embodiment, as in the Fig. 1 and Fig. As illustrated in Figure 2, it is desirable that when the tire radial direction dimension is between an outermost point P1 of the equatorial plane of the tire CL in the tire radial direction and an endpoint P2 of the tread rubber 26In the direction of tire width D, a tire cross-sectional height is SH is a tire radial direction height up to the position of the maximum tire width SWH is and the radius of curvature of the arc of the shoulder section R1 is, a relationship of TW × 0.04-(SWH / SH - 0.5) × 15 ≤ D ≤ TW × 0.07- (SWH / SH - 0.5) × 15 is satisfied, a relationship of 5 mm ≤ R1 ≤ 30 mm is satisfied, the ratio BW / TW of the width BW of the effective belt layer 24c to the tread width TW a relationship of 0.80 ≤ BW / TW ≤ 0.90 is satisfied, and the belt cover 28 on the outside in the tire width direction of the belt layer 24 a is designed with the maximum width (additional embodiment 1). It should be noted that in the Fig. 2 illustrated example the belt cover 28 includes two belt cover layers 28a and 28b which are connected in the tire radial direction.

[0025] Here, "tire cross-sectional height SH" refers to the tire radial dimension of a section of the contact between the bead section. 12 and the rim to the outermost position of the tread section 16 in the tire radial direction. "Tire radial direction height SWH" up to the maximum tire width refers to the tire radial direction dimension of a section of the contact patch between the bead section. 12 and the rim up to the maximum tire width position. The arc of the shoulder section refers to an arc that defines the outer contour of the shoulder section. 18 forms, which in the Fig. 1 and Fig. 2 is illustrated.

[0026] “Effective belt layer” refers to the belt layer 24c , whose outermost position in the direction of tire width under the belt layers ( 24a , 24b and 24c ), which the belt 24form, arranged on the innermost side in the direction of tire width.

[0027] By setting the tire radial direction dimension D to [TW x 0.04 - (SWH / SH - 0.5) x 15] or more, the rolling resistance in the normal load condition can be further reduced without excessively increasing the ground contact width (the tire width direction dimension in the ground contact condition).

[0028] In contrast, by adjusting the tire radial direction dimension D to equal to or less than [TW x 0.04 - (SWH / SH - 0.5) x 15] a sufficient ground contact width and thus a sufficient ground contact area of ​​the shoulder section can be ensured, the frictional force in the braking load condition can be further increased, and thus the dry braking performance can be further increased.

[0029] By adjusting the radius of curvature R1 of the shoulder section arc to 5 mm or more, the rolling resistance in the normal load condition can be further reduced without excessively increasing the ground contact width (a dimension in the tire width direction in the ground contact condition).

[0030] In contrast, by adjusting the radius of curvature R1 of the shoulder section arc to 30 mm or less, a sufficient ground contact width and thus a sufficient ground contact area of ​​the shoulder section can be ensured, the frictional force under braking load conditions can be further improved, and the dry braking performance can be further increased.

[0031] It should be noted that the radius of curvature R1 is more preferably 8 mm or more and 27 mm or less, and most preferably 10 mm or more and 25 mm or less.

[0032] Since the ratio BW / TW is 0.80 or more, the belt 24sufficient on the outside in the tire width direction of the tread section 16 This ensures and improves durability. Since the BW / TW ratio is 0.90 or less, it is possible to prevent the belt from 24 becomes unnecessarily long.

[0033] It should be noted that the BW / TW ratio is more preferred to be 0.82 or more and 0.88 or less, and most preferred to be 0.83 or more and 0.87 or less.

[0034] Since the belt cover 28 is on the outside in the tire width direction of the belt layer 24a If it is formed with a maximum width, a deflection of the shoulder section will occur. 18 suppressed during the rolling of the tire, and the occurrence of cracking originating from the end section of the belt. 24 It can be suppressed. Additional embodiment 2

[0035] Fig.3 is a tire meridian cross-sectional view of the in Fig. Figure 1 of the pneumatic tire of the present embodiment, which illustrates only one side in the tire width direction from the equatorial plane of the tire CL, which extends from the tread section 16 to the shoulder section 18 extends. In a basic embodiment and an embodiment in which the additional embodiment 1 is added to the basic embodiment, as in Fig. As illustrated in 3, the tread section closes 16preferably at least two main grooves extending in the circumferential direction of the tire (in the same drawing, two main grooves 32a and 32b on one side in the tire width direction from the equatorial plane of the tire), and the central position P3 in the tire width direction of the main groove 32b on the outermost side in the tire width direction under the main grooves 32a and 32b is preferably in a position at a distance of 1 / 4 or less of the tread width TW from the equatorial plane of the tire CL present (additional embodiment 2).

[0036] “Main groove” here refers to a groove in which a wear indicator must be provided in accordance with JATMA and which typically has a width of 2% or more of the tread width. TWexhibits. Furthermore, the center position P3 in the tire width direction of the main groove 32b on the outermost side in the tire width direction refers to the center position in the tire width direction of the groove bottom of the main groove 32b.

[0037] Since the center position P3 in the tire width direction of the main groove 32b is located on the outermost side in the tire width direction at a position at a distance of 1 / 4 or less of the tread width TW If CL is present at the equatorial plane of the tire, a sufficient ground contact area of ​​the shoulder section can be ensured. 18 to ensure that the main groove on the tread surface near the shoulder section is not damaged 18 To form, the frictional force under braking load can be further increased, and thus the dry braking performance can be further increased.

[0038] It should be noted that the center position P3 in the direction of tire width is more preferably in a position at a distance of 23 / 100 or less of the tread width. TW CL is present from the equatorial plane of the tire and is most preferably arranged in a position at a distance of 21 / 100 or less. Additional embodiment 3

[0039] Fig. 4 is a tire meridian cross-sectional view of the in Fig. Figure 1 of the pneumatic tire of the present embodiment, which illustrates only one side in the tire width direction from the equatorial plane of the tire CL, which extends from the tread section 16 to the shoulder section 18 extends. In the basic embodiment or an embodiment in which at least one of the additional embodiments 1 and 2 is added to the basic embodiment, as in Fig.Figure 4 illustrates an outer contour 42 of the tread section. 16 preferably a central section arc 42a located on a central section in the tire width direction, and a pair of shoulder arcs 42b connected to the outer side in the tire width direction of the central section arc 42a, and a relationship of 0.40 ≤ L / (TW / 2) ≤ 0.70 is preferably satisfied when the length in the tire width direction of the central section arc 42a is 2L (additional embodiment 3). It should be noted that although the central section arc 42a in Fig. 4 is only shown in one section on one side of the equatorial plane of the tire CL, half of which is actually present on the other side of the equatorial plane of the tire CL.

[0040] By adjusting the ratio L / (TW / 2) to 0.40 or more, the ground contact width and thus the ground contact area of ​​the shoulder section can be further ensured, the frictional force under braking load can be further improved, and the dry braking performance can be further increased.

[0041] In contrast, by setting the ratio L / (TW / 2) to 0.70 or less, the rolling resistance under normal load conditions can be further reduced without excessively increasing the ground contact width.

[0042] It should be noted that the ratio L / (TW / 2) is preferably 0.45 or more and 0.65 or less, and most preferably 0.50 or more and 0.60 or less. Additional embodiment 4

[0043] In the basic embodiment or an embodiment in which at least one of the additional embodiments 1 to 3 is added to the basic embodiment, it is preferred that the tire outer diameter is equal to or greater than the standard mean value (additional embodiment 4).

[0044] Here, "standard" refers to JATMA, TRA, or ETRTO, as described above. Furthermore, "standard mean" refers to a value that is in the middle when multiple outside diameters listed in JATMA or similar standards are arranged in ascending order.

[0045] By adjusting the tire's outer diameter to be equal to or smaller than the standard mean value, in other words, by increasing the tire's outer diameter to a certain degree, sufficient volume of the cavity within the tire can be ensured, both the deflection of the tire under braking load conditions and the deflection of the tire under normal load conditions can be reduced, and thus the rolling resistance can be reduced in both load conditions.

[0046] It should be noted that by adjusting the tire outer diameter so that it is equal to or greater than a value that is 3 mm smaller than the standard maximum value, the effect described above can be achieved at a higher level. Additional embodiment 5

[0047] In the basic embodiment or an embodiment in which at least one of the additional embodiments 1 to 4 is added to the basic embodiment, it is preferred that the overall tire width is equal to or greater than a standard mean value (additional embodiment 5).

[0048] Here, "standard" refers to JATMA, TRA, or ETRTO, as described above. Furthermore, "standard mean" refers to a value that lies in the middle in a case where multiple overall tire widths listed in JATMA or similar standards are arranged in ascending order.

[0049] By adjusting the overall tire width to be equal to or less than the standard mean value, in other words by increasing the tire's outer diameter to a certain degree, sufficient volume of the cavity within the tire can be ensured, both the deflection of the tire under braking load conditions and the deflection of the tire under normal load conditions can be reduced, and thus the rolling resistance can be reduced in both load conditions.

[0050] It should be noted that by adjusting the overall tire width to be equal to or greater than a value that is 3 mm smaller than the standard maximum value, the effect described above can be achieved at a higher level. Additional embodiment 6

[0051] Fig. 5 is a tire meridian cross-sectional view of the in Fig.Figure 1 of the pneumatic tire of the present embodiment, which illustrates only one side in the tire width direction from the equatorial plane of the tire CL, which extends from the bead section 12 to the tread section 16 extends. It should be noted that the in Fig. 5 illustrated examples show a type where the bead section 12 including a tire bead core 12a and a bead filler 12b, which is formed on the outside in the tire radial direction of the tire bead core 12a.

[0052] In a basic embodiment or an embodiment in which at least one of the additional embodiments 1 to 5 is added to the basic embodiment, as in Fig. As illustrated in Figure 5, it is preferred that a relationship of 0.50 ≤ F1 / SH ≤ 0.80 is satisfied when the tire radial direction dimension from the belt edge P4 to the bead filler top P5 is F1 (additional embodiment 6).

[0053] By setting the F1 / SH ratio to 0.50 or higher, an area that extends from the side wall section is created. 14 to the shoulder section 18 The shoulder section, which is likely to deform under load, is sufficiently deflected. This ensures adequate ground contact width and thus sufficient ground contact area of ​​the shoulder section, further improving friction under braking load and increasing dry braking performance. Conversely, setting the F1 / SH ratio to 0.80 or less suppresses excessive deflection of the area. This further reduces rolling resistance under normal load without unnecessarily increasing the ground contact width.

[0054] It should be noted that the F1 / SH ratio is more preferred to be 0.55 or more and 0.75 or less, and most preferred to be 0.60 or more and 0.70 or less. Additional embodiment 7

[0055] In the basic embodiment, or in an embodiment in which at least one of the additional embodiments 1 to 5 is added to the basic embodiment, it is preferred that a relationship of 0.50 ≤ F2 / SH ≤ 0.80 is satisfied when only the tire bead core is present in the bead section, the bead filler is not present, and the tire radial direction dimension from the belt edge to the bead core is defined as F2 (additional embodiment 7). It should be noted that this embodiment is a modified example of additional embodiment 6.

[0056] By setting the F2 / SH ratio to 0.50 or higher, an area that extends from the side wall section is created. 14to the shoulder section 18 The shoulder section, which is likely to deform under load, is sufficiently deflected. This ensures adequate ground contact width and thus sufficient ground contact area of ​​the shoulder section, further improving friction under braking load and increasing dry braking performance. Conversely, setting the F2 / SH ratio to 0.80 or less suppresses excessive deflection of the area. This further reduces rolling resistance under normal load without unnecessarily increasing the ground contact width.

[0057] It should be noted that the F2 / SH ratio is more preferred to be 0.55 or more and 0.75 or less, and most preferred to be 0.60 or more and 0.70 or less. Additional embodiment 8

[0058] Fig.6 is a tire meridian cross-sectional view of the in Fig. Figure 1 of the pneumatic tire of the present embodiment, which illustrates only one side in the tire width direction from the equatorial plane of the tire CL, which extends from the tread section 16 to the shoulder section 18 extends. In the basic embodiment or an embodiment in which at least one of the additional embodiments 1 to 7 is added to the basic embodiment, as in Fig. As shown in 6, preferably a belt edge spacing ES between the belt layer is fulfilled. 24a with maximum width and the belt layer 24c with a minimum width a relationship of 5 mm < ES < 15 mm (additional embodiment 8).

[0059] Here, "belt width" refers to the dimension of the belt layer in the tire width direction. The belt edge spacing ES refers to the distance between the outermost point of the belt layer in the tire width direction. 24a with the maximum width and the outermost point in the tire width direction of the belt layer 24c with the minimum width.

[0060] By setting the belt edge spacing ES to more than 5 mm, it is possible to ensure an area where only the belt layer with the maximum width is present in the outer section in the tire width direction. This prevents deflection of the shoulder section. 18 This can be adequately achieved, and the ground contact width can be further reduced. As a result, the rolling resistance under normal load conditions can be further reduced.

[0061] In contrast, by setting the belt edge spacing ES to less than 15 mm, there is no excessively large area in the tire width direction where the belt layer with the maximum width is formed, but the belt layer with the smallest width is not. Thus, the occurrence of cracks originating from the end section of the belt can be reduced. 24 exits when the side wall section 14 being distracted will be further suppressed.

[0062] It should be noted that the belt edge spacing ES is more preferably 7 mm or more and 13 mm or less, and most preferably 8 mm or more and 12 mm or less. Additional embodiment 9

[0063] In the basic embodiment, or in an embodiment in which at least one of the additional embodiments 1 to 8 is added to the basic embodiment, it is preferred that a relationship of 4.5 mm ≤ GD ≤ 7.5 mm is satisfied when the depth of at least one main groove, including the equatorial plane of the tire, or one main groove (for example, the main grooves 32a and 32b, which are in Fig. 3 are illustrated), which is closest to the equatorial plane of the tire under the main grooves GD (additional embodiment 9).

[0064] Here, the groove depth GD of the main groove refers to the dimension of the longest line segment from the tire tread line to the groove bottom under the vertical lines in relation to the tire tread line (the outer contour of the tire when the main groove is not present).

[0065] By setting the groove depth (GD) of the main groove to 4.5 mm or more, the wear life of the main groove can be sufficiently ensured until it is worn down and the wear indicator is exposed, thus maintaining drainage performance for a long period. Conversely, by setting the groove depth (GD) of the main groove to 7.5 mm or less, it is possible to further reduce rolling resistance under normal load without unnecessarily increasing the amount of tread rubber.

[0066] It should be noted that the groove depth GD of the main groove is more preferably 5.0 mm or more and 7.0 mm or less, and most preferably 5.5 mm or more and 6.5 mm or less. Example

[0067] Pneumatic tires according to examples 1 to 9 and comparative examples 1 to 3 with a tire size of 205 / 60R16 92 V and a Fig.The tire meridian cross-sectional shape shown in Figure 1 (including bead fillers and bead cores in the bead sections) is manufactured. It should be noted that the detailed specifications of these pneumatic tires are as shown in Tables 1 and 2 below. It should be noted that Tables 1 and 2 TW indicates the tread width SW CW100 indicates the total tire width, CW100 indicates the ground contact width at a load of 100% of the maximum load capacity, CW70 indicates the ground contact width at a load of 70% of the maximum load capacity, and D indicates a tire radial dimension between the outermost point in the tire radial direction of the equatorial plane of the tire and the endpoint in the tire width direction of the tread rubber. SH specifies a tire cross-sectional height, SWHR1 specifies a height in the tire radial direction up to a tire maximum width position, R1 specifies the radius of curvature of the shoulder section arc, BW specifies the width of the effective belt layer, GC specifies the distance from the equatorial plane of the tire to a center position in the tire width direction of the outermost main groove, L specifies the length of half the length in the tire width direction of the center section arc, F1 specifies a tire radial direction dimension from the belt edge to the bead filler top, ES specifies a belt edge distance between the belt layer with the maximum width and the belt layer with the minimum width, and GD specifies the depth of the main groove.

[0068] Pneumatic tires of Examples 1 to 9 and of Comparison Examples 1 to 3, which were manufactured in this way, were evaluated with respect to rolling resistance and dry braking performance according to the following procedures. Rolling resistance

[0069] The test tires are mounted on 16 x 6 J rims on a drum tire testing machine, and a rolling resistance coefficient (RRC) is measured according to ISO 25280 under conditions of an air pressure of 210 kPa and an applied load of 4.94 kN. The evaluation results are shown by index values ​​relative to 100 of reference example 1, using the reciprocals of the measured values. The higher the index value, the lower the rolling resistance. The results are also presented in Tables 1 and 2. Dry braking performance

[0070] The test tires were mounted on 16 x 6 J rims on a passenger car, inflated to a front / rear pressure of 240 kPa after warm-up, and a braking distance from an initial speed of 100 km / h to a complete stop was measured on dry road surfaces. The evaluation results are shown by index values ​​relative to 100 of the reference example 1, using the reciprocals of the measured values. The higher the index value, the better the braking performance on dry road surfaces. The results are also presented in Tables 1 and 2. [Table 1] Example 1 Example 2 Example 3 Example 4 Example 5 Example 6 TW (mm) 166 180 180 180 180 190 SW (mm) 206 206 206 206 206 215 TW / SW 0,81 0,87 0,87 0,87 0,87 0,88 CW100 (mm) 160 170 170 170 170 176 CW70 (mm) 150 160 160 160 160 154 CW100 / CW70 1,07 1,06 1,06 1,06 1,06 1,14 SH (mm) 121,8 121,8 121,8 121,8 124,8 124,8 SWH (mm) 59 59 59 59 59 59 TW x 0.04 - (SWH / SH - 0.5) x 15 6,9 7,4 7,4 7,4 7,6 8,0 TW x 0.07 - (SWH / SH - 0.5) x 15 11,9 12,8 12,8 12,8 13,0 13,7 D (mm) 6 8 8 8 8 10 R1 (mm) 35 25 25 25 25 15 BW (mm) 160 155 155 155 155 155 BW / TW 0,96 0,86 0,86 0,86 0,86 0,82 Presence / absence of a belt cover No Yes Yes Yes Yes Yes TW × 1 / 4 (mm) 41,5 45 45 45 45 47,5 GC (mm) 46 46 42 42 42 42 L (mm) 30 35 35 42 42 42 L / (TW / 2) 0,36 0,39 0,39 0,47 0,47 0,47 Standard mean tire outer diameter (mm) 652 652 652 652 652 652 Tire outer diameter (mm) 650 650 650 650 656 656 Standard mean tire width (mm) 209 209 209 209 209 209 Total tire width (mm) 206 206 206 206 206 215 F1 (mm) 60 60 60 60 60 60 F1 / SH 0,49 0,49 0,49 0,49 0,48 0,48 ES (mm) 5 5 5 5 5 5 GD (mm) 8 8 8 8 8 8 Rolling resistance 100 100 100 101 103 103 Dry braking performance 101 102 102,5 102,5 102,5 104 [Table 2] Example 7 Example 8 Example 9 Comparative example 1 Comparative example 2 Comparative example 3 TW (mm) 190 190 190 160 166 158 SW (mm) 215 215 215 206 206 206 TW / SW 0,88 0,88 0,88 0,78 0,81 0,77 CW100 (mm) 176 176 176 154 159 153 CW70 (mm) 154 154 154 150 155 147 CW100 / CW70 1,14 1,14 1,14 1,03 1,03 1,04 SH (mm) 124,8 124,8 124,8 122 122 122 SWH (mm) 59 59 59 59 59 59 TW x 0.04 - (SWH / SH - 0.5) x 15 8,0 8,0 8,0 6,6 6,9 6,6 TW x 0.07 - (SWH / SH - 0.5) x 15 13,7 13,7 13,7 11,4 11,9 11,3 D (mm) 10 10 10 6 6 6 R1 (mm) 15 15 15 35 35 35 BW (mm) 155 155 155 155 160 155 BW / TW 0,82 0,82 0,82 0,97 0,96 0,98 Presence / absence of a belt cover Yes Yes Yes No No No TW × 1 / 4 (mm) 47,5 47,5 47,5 40 41,5 39,5 GC (mm) 42 42 42 46 46 40 L (mm) 42 42 42 30 32 30 L / (TW / 2) 0,44 0,44 0,44 0,38 0,39 0,38 Standard mean tire outer diameter (mm) 652 652 652 652 652 652 Tire outer diameter (mm) 656 656 656 650 650 650 Standard mean tire width (mm) 209 209 209 209 209 209 Total tire width (mm) 215 215 215 206 206 206 F1 (mm) 80 80 80 60 60 60 F1 / SH 0,64 0,64 0,64 0,49 0,49 0,49 ES (mm) 5 10 10 5 5 5 GD (mm) 8 7 7 8 8 8 Rolling resistance 104 105 106 100 95 101 Dry braking performance 104 104 104,5 100 101 98

[0071] Table 1 shows that the pneumatic tires of Examples 1 to 9, which are part of the technical scope of the present invention (i.e., improvements are to be made to TW / SWand CW100 / CW70 added), are superior in both rolling resistance and dry braking performance compared to the pneumatic tires of comparative examples 1 to 3, which are not part of the technical scope of the present invention. Reference symbol list 10 pneumatic tires 12 bead section 14 Side wall section 16 tread section 18 Shoulder section 22 Carcass 24 belts 24a, 24b, 24c Belt layer 26 tread rubber TW tread width SW tire total width SH tire cross-section height SWH height in tire radial direction up to the position with maximum tire width QUOTES INCLUDED IN THE DESCRIPTION

[0000] This list of documents cited by the applicant was automatically generated and is included solely for the reader's convenience. The list is not part of the German patent or utility model application. The DPMA accepts no liability for any errors or omissions. Cited patent literature

[0000] JP 5469692 B

[0003] JP 5952587 B

[0003]

Claims

[1] Pneumatic tires, including: a pair of left and right bulge sections; Sidewall sections that are connected to an outer surface in the radial direction of the bead sections; a running surface section that extends between the side wall sections; a carcass, including at least one carcass ply, which extends in a torus shape between the pair of left and right bead sections; a belt, including at least one belt layer, arranged on an outer surface in a tire radial direction of the carcass and enclosing cord threads; and a tread rubber arranged on an outer side in the tire radial direction of the belt and forming a section of the tread section, in a state where the pneumatic tire is mounted on a normal rim and inflated to 5% of a specified internal pressure, where a tread width W and a total tire width SW in a tire meridian cross-sectional view, a relationship of 0.80 ≤ TW / SW ≤ 0.95 is satisfied, and where a ground contact width at a load of 100% of a maximum load capacity is CW100 and a ground contact width at a load of 70% of the maximum load capacity is CW70, a relationship of 1.04 <_ CW100 / CW70 ≤ 1.15 is satisfied. [2] Pneumatic tires according to claim 1, wherein then, if a tire radial direction dimension between an outermost point in the tire radial direction of an equatorial plane of the tire and an endpoint in the tire width direction of the tread rubber is D, a tire cross-sectional height is SH, a tire radial direction height up to a tire maximum width position is SWH, and a radius of curvature of an arc of the shoulder section is R1, and a relationship of TW × 0.04 - (SWH / SH - 0.5) × 15 ≤ D ≤ TW × 0.07 - (SWH / SH - 0.5) × 15 and a relationship of 5 mm ≤ R1 ≤ 30 mm are satisfied, and a ratio BW / TW of a width BW of an effective belt layer and the tread width TW fulfills a relationship of 0.80 ≤ BW / TW ≤ 0.90 and a belt cover is formed on an outside in the tire width direction of a belt layer with a maximum width. [3] Pneumatic tire according to claim 1 or 2, wherein the tread section includes at least two main grooves extending in a tire circumferential direction, and a central position in the tire width direction of the main groove is located on an outermost side in the tire width direction of the main grooves at a position at a distance of 1 / 4 or less of the tread width TW from the equatorial plane of the tire. [4] Pneumatic tire according to any one of claims 1 to 3, wherein an outer contour of the tread section includes a central section arc arranged on a central section in the tire width direction and a pair of shoulder arcs connected to the outer side in the tire width direction of the central section arc, and where if a length in the tire width direction of the central section arc is 2L, a relationship of 0.40 ≤ L / (TW / 2) ≤ 0.70 is satisfied. [5] Pneumatic tires according to any one of claims 1 to 4, wherein a tire outer diameter is equal to or greater than a standard mean value. [6] Pneumatic tires according to any one of claims 1 to 5, wherein the overall tire width is equal to or greater than a standard mean value. [7] Pneumatic tire according to any one of claims 1 to 6, wherein the bead section includes a tire bead core and a bead filler formed on an outer side in the tire radial direction of the tire bead core, and where a tire radial direction dimension from a belt edge to a bead filler top side is F1, a relationship of 0.50 ≤ F1 / SH ≤ 0.80 is satisfied. [8] Pneumatic tire according to any one of claims 1 to 6, wherein the bead section comprises a tire bead core and a rubber layer formed on an outer surface in the tire radial direction of the tire bead core, and where a tire radial direction dimension from a belt edge to a tire bead core is F2, a relationship of 0.50 ≤ F2 / SH ≤ 0.80 is satisfied. [9] Pneumatic tire according to any one of claims 1 to 8, wherein a belt edge distance ES between a belt layer with a maximum width and a belt layer with a minimum width satisfies a relationship of 5 mm < ES < 15 mm. [10] Pneumatic tire according to any one of claims 1 to 9, wherein, if a depth of at least one main groove including the equatorial plane of the tire, or of a main groove closest to the equatorial plane of the tire under the main grooves is GD, a relationship of 4.5 mm ≤ GD ≤ 7.5 mm is satisfied.