pneumatic tires

Abstract

Pneumatic tires (1) with a specified vehicle mounting direction, comprising: in a tire tread section (10), at least one main groove (14, 14a, 14b, 14c, 14d) extending in a tire circumferential direction; and a plurality of inclined grooves (20, 22, 24, 26, 28) intersecting the main groove (14, 14a, 14b, 14c, 14d); on an inner vehicle mounting side (TI) in a region on an outer side in the tire width direction of the main groove (14, 14a, 14b, 14c, 14d) arranged on an outermost side in the tire width direction, pitch spacing lengths (Pi) which have pitch spacing variations in the tire circumference direction, including at least three pitch spacing lengths (Pi) in a region formed by the inclined grooves (20, 22, 24, 26, 28) and web sections adjacent to the inclined grooves (20, 22, 24, 26, 28) on a side in the tire circumference direction; and If a number of division intervals is fixed at n and division interval lengths (Pi) are defined as Pi1, Pi2, Pi3,..., Pin in order of a largest division interval length, then the relationships Pi1 / Pi2 ≤ Pi2 / Pi3 ≤,... ≤ Pin-1 / Pin and Pi1 / Pi2 < Pin-1 / Pin are satisfied, where on an outer vehicle mounting side (TO) in a region on an outer side in the tire width direction of the main groove (14, 14a, 14b, 14c, 14d) which is arranged on the outermost side in the tire width direction, pitch spacing lengths (Po) which have pitch spacing variations in the tire circumference direction, including at least three pitch spacing lengths (Po) in a region formed by the inclined grooves (20, 22, 24, 26, 28) and web sections adjacent to the inclined grooves (20, 22, 24, 26, 28) on a side in the tire circumference direction; and If a number of division intervals is fixed to n and division interval lengths (Po) are defined as Po1, Po2, Po3,..., Pon in order of a largest division interval length, then the relationships Po1 / Po2 ≥ Po2 / Po3 ≥,..., ≥ Pon-1 / Pon and Po1 / Po2 > Pon-1 / Pon are satisfied.

Description

Technical field

[0001] The present invention relates to a pneumatic tire with pitch spacing variations in its tread pattern. background

[0002] Pneumatic tires with varying pitch spacing in their tread patterns are known in the art (see, for example, patent documents 1 to 3). Patent document 1 discloses a technique in which wet performance is improved by specifying pitch spacing lengths, angles of inclination of transverse grooves, and groove areas of the transverse grooves. Patent document 2 discloses a technique in which noise performance is improved by specifying pitch spacing lengths and widths of transverse grooves. Patent document 3 discloses a technique in which noise performance is improved by specifying a change ratio between groove cross-sections. Patent document 4 describes a pneumatic tire comprising a tread section with a main groove extending in the circumferential direction and several inclined grooves intersecting the main groove.On an inner vehicle mounting side, in an area on an outer side in a tire width direction of the main groove, which is positioned on an outermost side in the tire width direction, the circumferential pitch lengths of the tire exhibit pitch variations comprising at least three pitch lengths. Patent document 5 describes a pneumatic tire with multiple block elements arranged in a circumferential direction of the tire and formed in each of the areas separated by a tire equator in a tread section of the tire. State of the art documents

[0003] Patent document Patent document 1: JP H11-291 714 A Patent document 2: JP 2007- 168 572 A Patent document 3: JP H71-79 103 A Patent document 4: US 5,027,875 A Patent document 5: JP 2009- 262 874 A Brief description of the invention Problems to be solved by the invention

[0004] In the techniques disclosed in patent documents 1 to 3, in addition to the pitch spacing lengths, the inclination angles and areas of the transverse grooves, the groove widths of the transverse grooves or the cross-sectional change ratio of specific grooves must be specified; this complicates the design.

[0005] In view of the circumstances described above, it is an object of the present invention to provide a pneumatic tire which is achieved without having to make modifications to factors other than the pitch spacing lengths, for example the inclination angles of the transverse grooves, the groove areas and the groove widths, that is to say, without the need for a complicated design, and wherein the noise performance (with respect to the sample noise) is improved. Means of solving the problems

[0006] A pneumatic tire according to the present invention has a predetermined vehicle mounting direction and is equipped in a tire tread section with at least one main groove extending in a tire circumferential direction and a plurality of inclined grooves intersecting the main groove. On an inner vehicle mounting side, in a region on an outer side in the tire width direction of the main groove, which is arranged on the outermost side in the tire width direction, pitch spacing lengths in the tire circumferential direction have pitch spacing variations that include at least three pitch spacing lengths in a region formed by the inclined grooves and rib sections adjacent to the inclined grooves on a side in the tire circumferential direction. If the number of pitch spacings is fixed to n and pitch spacing lengths Pi are each designated as Pi1, Pi2, Pi3,..., Pin are defined in order of the largest division distance length, relationships Pi1 / Pi2 ≤ Pi2 / Pi3 ≤... ≤ Pin-1 / Pin and Pi1 / Pi2 < Pin-1 / Pin are satisfied. Effect of the invention

[0007] In the pneumatic tire according to the present invention, modifications are made only to the pitch-to-pitch ratios based on the pitch-to-pitch lengths, and not to any other factors. In this way, the pneumatic tire is obtained without a complicated design and can improve the noise performance (with respect to the sample noise). Brief description of the drawings Fig. Figure 1 is a top view showing a tread section of a pneumatic tire according to an embodiment of the present invention. Fig. 2 is a top view showing part of an inner vehicle assembly side TI in the tread section. Fig. 1 represents. Fig. 3 is a top view showing part of an outer vehicle assembly side TO in the tread section. Fig. 1 represents. Best way to implement the invention

[0008] With reference to the drawings, embodiments of the pneumatic tire according to the present invention will now be described (basic embodiment and further embodiments 1 to 5, described below). It should be noted that the present invention is not limited to these embodiments. Furthermore, the elements constituting the embodiments may include elements that can be readily substituted by those skilled in the art, or elements that are essentially the same. In addition, the various modes included in these embodiments may be combined as needed within the scope that is obvious to those skilled in the art. [Embodiment according to the invention]

[0009] One embodiment of the pneumatic tire according to the present invention will now be described.

[0010] In the following description, "tire radial direction" refers to a direction perpendicular to the axis of rotation of the pneumatic tire; "inside in tire radial direction" refers to a side that is close to the axis of rotation in the tire radial direction; and "outside in tire radial direction" refers to a side that is farther from the axis of rotation in the tire radial direction. Furthermore, "tire circumferential direction" refers to a direction around the axis of rotation as the central axis. Additionally, "tire width direction" refers to a direction parallel to the axis of rotation; "inside in tire width direction" refers to a side that is close to an equatorial plane of the tire CL (the equatorial line of the tire) in the tire width direction; and "outside in tire width direction" refers to a side that is farther from the equatorial plane of the tire CL in the tire width direction.It should be noted that the “equatorial plane of the tire CL” refers to a plane that is orthogonal to the axis of rotation AX of the pneumatic tire 1 and passes through the center of the width of the pneumatic tire 1.

[0011] Fig. Figure 1 is a top view showing a tread section of a pneumatic tire according to an embodiment of the present invention. A pneumatic tire 1 made of Fig.The tire 1 has a predetermined vehicle mounting direction. In the same illustration, the side to the left of the tire's equatorial plane CL is an inner vehicle mounting side TI, and the side to the right of the tire's equatorial plane CL is an outer vehicle mounting side TO. The pneumatic tire 1 also has a tread section 10. The tread section 10 is made of a rubber material (tread rubber) and is located on the outermost side of the pneumatic tire 1 in the radial direction; therefore, its surface forms the profile of the pneumatic tire 1. The surface of the tread section 10 forms a tread surface 12, which is a surface that comes into contact with the road surface when a vehicle (not shown) on which the pneumatic tire 1 is mounted is moving.

[0012] As in Fig.As shown in Figure 1, the tread surface 12 is provided with grooves 14, 16, and 18 extending in the circumferential direction of the tire, inclined grooves 20, 22, 24, 26, and 28 inclined relative to the circumferential direction of the tire, and sipes 30 to form the tread pattern shown in the same illustration. The specific configuration of the grooves 14 to 28 and the sipes 30 is as follows.

[0013] The tread surface 12 is provided with main circumferential grooves 14 extending in the tire's circumferential direction (one main circumferential groove 14a on the inner vehicle mounting side TI and on the inside in the tire width direction, one main circumferential groove 14b on the inner vehicle mounting side TI and on the outside in the tire width direction, one main circumferential groove 14c on the outer vehicle mounting side TO and on the inside in the tire width direction, and one main circumferential groove 14d on the outer vehicle mounting side TO and on the outside in the tire width direction). A secondary circumferential groove 16a, narrower than the main circumferential groove 14b, is provided on the outside in the tire width direction of the main circumferential groove 14d. A secondary circumferential groove 16b, narrower than the main circumferential groove 14d, is provided on the outside in the tire width direction of the main circumferential groove 14d.On the outer side in the direction of tire width beyond the secondary circumferential groove 16b, an interrupted circumferential groove 18 is provided, which extends with interruption in the direction of the tire circumference and is as narrow as the secondary circumferential groove 16b.

[0014] Furthermore, the tread surface 12 on the outer side, in the tire width direction beyond the secondary circumferential groove 16a, is provided with an inclined, interrupted groove 20, which is inclined relative to the tire circumference, extends with interruptions in the tire circumference direction, and is as narrow as the secondary circumferential groove 16a. A plurality of inclined grooves 22 are provided, extending from the inside in the tire width direction of the main circumferential groove 14b, terminating in a web section adjacent to the main circumferential groove 14b, and inclined relative to the tire circumference direction. A plurality of inclined grooves 24 are provided, extending from the outside in the tire width direction of the main circumferential groove 14c, terminating in a web section adjacent to the main circumferential groove 14b, and inclined relative to the tire circumference direction.A plurality of inclined grooves 26 are provided, which intersect a secondary circumferential groove 16a and in which the inner ends terminate in a web section adjacent to the secondary circumferential groove 16a in the tire width direction, and the outer ends extend on the outer side in the tire width direction of an inclined interrupted groove 20. On the outer side in the tire width direction of the secondary circumferential groove 16b, a plurality of inclined grooves 28 are provided, which intersect regions in the tire circumference direction of the interrupted circumferential groove 18 and are inclined relative to the tire circumference direction.

[0015] Furthermore, sipes 30a are provided, extending inwards from the main circumferential groove 14b in the tire width direction and terminating in the rib section, such that they alternate with the inclined grooves 22 in the tire circumference direction. A plurality of sipes 30b are provided, extending adjacent to each other between the neighboring areas of the outermost regions of the inclined grooves 24 in the tire width direction and having a shape that is convex outwards in the tire width direction. Sipes 30c are provided, extending outwards from the secondary circumferential groove 16a in the tire width direction and terminating in the rib section, such that they alternate with the inclined grooves 26 in the tire circumference direction.Sipes 30d, which extend outwards in the tire width direction from the main circumferential groove 14d beyond the secondary circumferential groove 16b and terminate in the rib section, are provided such that they alternate in the tire circumferential direction with sipes 30e, which extend inwards in the tire width direction from the inclined grooves 28 beyond the secondary circumferential groove 16b and terminate in the rib section.

[0016] Under these conditions, the in Fig.In the example shown, on an inner vehicle mounting side in a region on an outer side in the tire width direction of the main circumferential groove 14b, which is arranged on the outermost side in the tire width direction, pitch spacing lengths in the tire circumferential direction pitch spacing variations which include at least three pitch spacing lengths in a region formed by the inclined grooves 26 and web sections adjacent to the inclined grooves 26 on a side in the tire circumferential direction.

[0017] Fig. Figure 2 is a top view showing part of the inner vehicle assembly side TI of the tread section. Fig. 1 represents the arrangement of the grooves. Fig. 2 (especially the ratios of the tire circumference lengths) in Fig. 1 not exactly reflected, but the arrangement of the grooves on the inner vehicle mounting side TI corresponds to the arrangement in Fig. 2. In the example from Fig.2 denotes the pitch spacing length in the tire circumferential direction on the inner vehicle mounting side TI, with the center of gravity on any of the inclined grooves 26 (26a, 26b, 26c, ...), for example on the inclined groove 26a, the dimensions in the tire circumferential direction from the end on one side (for example the underside in Fig. 2) in the circumferential direction of the inclined groove 26a to the end on one side (for example, the underside in Fig. 2) in the circumferential direction of the tire a sloping groove 26b which is identical to the sloping groove 26a and is adjacent to it in the circumferential direction of the tire.

[0018] In this context, an inclined groove, which serves as a reference when determining the pitch spacing length in the tire circumference direction, is not to be applied to the inclined groove 26. Fig. 2 is limited and can be another groove, such as the inclined groove 20 or the lamella 30c from the same illustration

[0019] In the example from Fig. Figure 2 features the tread pattern pitch spacing variations, which include three pitch spacing lengths on the inner vehicle mounting side TI. For example, in a case where the inclined grooves 26 (the inclined groove 26a, the inclined groove 26b and the inclined groove 26c) are specified as the inclined reference grooves, there are three pitch spacing lengths, which include a pitch spacing length Pi (reference: inclined groove 26a), a pitch spacing length Pi' (reference: inclined groove 26b) and a pitch spacing length Pi'' (reference: inclined groove 26c).

[0020] If, in the present embodiment, the number of division intervals is fixed at n and division interval lengths Pi are defined as Pi1, Pi2, Pi3,..., Pin in order of the largest division interval length, the relationships Pi1 / Pi2 ≤ Pi2 / Pi3 ≤,..., ≤ Pin - 1 / Pin (first condition), and Pi1 / Pi2 < Pin - 1 / Pin (second condition) are satisfied.

[0021] Since in the example from Fig. 2. If the division distance length Pi, the division distance length Pi' and the division distance length Pi'' increase in size in this order, then Pi corresponds to the division distance length Pi1, Pi' to the division distance length Pi2 and Pi'' to the division distance length Pi3, the relationships Pi / Pi' ≤ Pi' / Pi'' and Pi / Pi' < Pi' / Pi'' are satisfied, or, more simply, a relationship Pi / Pi' < Pi' / Pi'' is satisfied. (Effect and the like)

[0022] As described above, the pneumatic tire has 1 out of Fig.1. On the inner vehicle assembly side TI, a plurality of pitch distance lengths are defined in the circumferential direction. Based on this, a plurality of the quotients (the pitch results) of the pitch distance lengths with values ​​that are close to each other are determined among these pitch distance lengths, and the dimensional relationships of these quotients are established. Furthermore, based on the plurality of pitch distance lengths in the circumferential direction, the dimensional relationship between the quotient for the maximum pitch distance length and the quotient for the minimum pitch distance length is also established.In particular, the lengths are defined such that the ratio of the circumferential division lengths is smaller for longer division lengths when values ​​are close together, and conversely, the ratio of the circumferential division lengths is larger for shorter division lengths when values ​​are close together. Furthermore, the ratio for the maximum division length is set to be smaller than the ratio for the minimum division length.

[0023] This means that, with the first and second conditions, the majority of pitch distances are varied overall by reducing the minimum pitch distance on the inner vehicle mounting side when there is a high probability of influencing the sample noise measured inside the vehicle. In this way, it is possible to spread the frequency of the sample noise and prevent an amplification effect of noises in the same frequency band, and the noise performance (with respect to the sample noise) can be improved.

[0024] At the in Fig. In the pneumatic tire 1 shown, only modifications to the pitch ratios based on the pitch lengths were made, and no modifications were made to factors other than the pitch length. In particular, the pneumatic tire 1 is made of Fig.1. This is not achieved by specifying factors other than the pitch spacing length, such as the angle of inclination, areas, or widths of the transverse grooves, as is the case in the prior art in connection with pitch spacing variations (for example, patent documents 1 to 3). Therefore, the pneumatic tire can be made of Fig. 1 can be obtained without the need for a complicated interpretation.

[0025] In this way, according to the present embodiment, the pneumatic tire can improve the noise performance (with respect to the sample noise) without the need for a complicated design by simply regulating a plurality of pitch spacing lengths in the circumferential direction on the inner vehicle mounting side.

[0026] Although not shown in the drawings, the pneumatic tire described above, according to the present embodiment, has a meridional cross-sectional shape similar to that of a conventional pneumatic tire. Here, the meridional cross-sectional shape of the pneumatic tire refers to the cross-sectional shape of the pneumatic tire on a plane perpendicular to the tire's equatorial plane. Viewed in the meridional cross-section of the tire from the inside to the outside in the tire's radial direction, the pneumatic tire according to the present embodiment comprises a bead section, a sidewall section, a shoulder section, and a tread section.As can be seen, for example, when looking at the meridian cross-section of the tire, the pneumatic tire is provided with a carcass layer that extends from the tread section to the bead sections on both sides and is wrapped around a pair of bead cores, and a belt layer and a belt reinforcement layer that are formed in that order on the outside in the tire radial direction of the carcass layer.

[0027] The pneumatic tire can be obtained by various ordinary manufacturing steps, including a step of mixing tire material, a step of processing the tire material, a step of forming a raw tire, a vulcanization step, a post-vulcanization inspection step, and the like. In the manufacture of the pneumatic tire according to the present embodiment, in particular, a concave section and a convex section, corresponding to a tread pattern with desired pitch variations, are formed in the inner wall of a vulcanization mold, which is used to carry out the vulcanization.

[0028] Next, additional embodiments that can be implemented optionally will be described.

[0029] In the embodiment according to the invention, the outer vehicle mounting side TO is provided with a further modification. That is to say, in the present embodiment in the example from Fig. 1, on an outer vehicle mounting side TO in a region on the outside in the tire width direction of the main circumferential groove 14d, which is arranged on the outermost side in the tire width direction, pitch spacing lengths in the tire circumferential direction pitch spacing variations which include at least three pitch spacing lengths in a region formed by the inclined grooves 28 and web sections adjacent to the inclined grooves 28 on one side in the tire circumferential direction.

[0030] Fig. 3 is a top view showing part of the outer vehicle assembly side TO of the tread section. Fig. 1 represents the arrangement of the grooves. Fig. 3 (especially the ratios of the tire circumference lengths) in Fig. 1 not exactly reflected, but the arrangement of the grooves on the outer vehicle mounting side TO corresponds to the arrangement in Fig. 3. In the example from Fig. 3 denotes the pitch spacing length in the tire circumferential direction on the outer vehicle mounting side TO, with the center of gravity on any one of the inclined grooves 28 (28a, 28b, 28c, ...), for example on the inclined groove 28a, the dimensions in the tire circumferential direction from the end on one side (for example the underside in Fig. 3) in the circumferential direction of the inclined groove 28a to the end on one side (for example, the underside in Fig. 3) in the circumferential direction of the inclined groove 28b, which is identical to the inclined groove 28a and is adjacent to it in the circumferential direction of the tire.

[0031] In this context, an inclined groove, which serves as a reference when determining the pitch spacing length in the tire circumference direction, is not to be applied to the inclined groove 28. Fig. 3 is limited and can be another groove, such as the interrupted circumferential groove 18, the lamella 30c or the lamella 30e from the same representation.

[0032] In the example from Fig. 3 features the outer vehicle mounting side TO pitch spacing variations, which include three pitch spacing lengths. For example, in a case where the inclined grooves 28 (the inclined grooves 28a, 28b and 28c) are specified as reference grooves, there are three pitch spacing lengths, which include a pitch spacing length Po (reference: inclined groove 28a), a pitch spacing length Po' (reference: inclined groove 28b) and a pitch spacing length Po'' (reference: inclined groove 28c).

[0033] If, in the present mode according to the present invention, the number of division intervals is fixed at n and division interval lengths Po are defined as Po1, Po2, Po3,..., Pon in that order of the largest division interval length, then the relationships Po1 / Po2 ≥ Po2 / Po3 ≥,..., ≥ Pon - 1 / Pon (third condition) and Po1 / Po2 > Pon - 1 / Pon (fourth condition) are satisfied. Since in the example from Fig. 3. If the division distance length Po, the division distance length Po' and the division distance length Po'' increase in size in this order, then Pi corresponds to the division distance length Po1, Po' to the division distance length Po2 and Po'' to the division distance length Po3, and the relationships Po / Po' > Po' / Po'' are satisfied, or, more simply, a relationship Po / Po' > Po' / Po'' is satisfied.

[0034] As described above, a plurality of pitch interval lengths are defined in the circumferential direction on the outer vehicle mounting side TO of the pneumatic tire 1 of the present invention. Based on this, a plurality of the quotients (the pitch results) of the pitch interval lengths with values ​​that are close to each other are determined among these pitch interval lengths, and the relative values ​​of these quotients are established. Furthermore, based on the plurality of pitch interval lengths in the circumferential direction, the relative value between the quotient for the maximum pitch interval length and the quotient for the minimum pitch interval length is also established.In particular, the lengths are defined such that the ratio of the circumferential division lengths is larger for longer division lengths when values ​​are close together, and conversely, the ratio of the circumferential division lengths is smaller for shorter division lengths when values ​​are close together. Furthermore, the ratio for the maximum division length is set higher than the ratio for the minimum division length.

[0035] This means that, using the third and fourth conditions, on the outer vehicle mounting side TO, where the load difference is large when the tire rolls, the pitch difference is suppressed across the entire tire circumference by increasing the minimum pitch, thereby reducing stiffness differences. In this way, it is possible to improve steering stability performance on dry road surfaces.

[0036] In another embodiment or mode, the number of pitch intervals of pitch length Pi1 on the inner vehicle mounting side TI is preferably smaller than the number of pitch intervals of Pin on the tire circumference. This makes it possible to include a large number of sections with the smallest pitch interval length on the inner vehicle mounting side TI, which have a significant impact on fulfilling the first and second conditions. This allows for further variation of the total number of pitch interval lengths, and the noise performance (with respect to the pattern noise) can be further improved.

[0037] In a further embodiment, on the outer vehicle mounting side TO, the number of pitch intervals of pitch length Po1 around the tire circumference is preferably smaller than the number of pitch intervals of Pon around the tire circumference. This makes it possible to include a large number of sections with the smallest pitch interval length on the outer vehicle mounting side TO, which have a significant impact on fulfilling the third and fourth conditions. In this way, it is possible to further reduce stiffness differences by further suppressing differences in pitch interval lengths across the entire tire circumference, and steering stability performance on dry road surfaces can be further improved.

[0038] In a further embodiment, when the number of division intervals is set to n, at least one of the division interval length ratio Pik - 1 / Pik, where k is at least one of the natural numbers 2 to n, is located on the inner vehicle mounting side TI, and the division interval length ratio Pok - 1 / Pok, where k is at least one of the natural numbers 2 to n, is located on the outer vehicle mounting side TO, preferably in a range of 1.05 to 1.20.

[0039] By setting at least one of the pitch-spacing ratios Pik - 1 / Pik and Pok - 1 / Pok to 1.05 or greater on the inner vehicle mounting side TI and the outer vehicle mounting side TO, where this value is applied, it is possible to vary the dimensions between pitch-spacing lengths with similar dimensions to a certain extent. In this way, it is possible to disperse the sound frequency generated on sides TI and TO and to prevent the amplification effect of sound in the same frequency band. This makes it possible to reduce the sample noise measured inside the vehicle on the inner vehicle mounting side TI, and the noise performance (with respect to the sample noise) can be further improved.Furthermore, it is possible to reduce the pass-by noise measured outside the vehicle on the outer vehicle mounting side TO, and the noise performance (with regard to pass-by noise) can be further improved.

[0040] Furthermore, by setting at least one of the pitch ratios (Pik - 1 / Pik) and the pitch ratio (Pok - 1 / Pok) to 1.20 or less on the inner mounting side (TI) and the outer mounting side (TO) where this value is applied, the dimensions between pitch lengths with similar dimensions are not varied more than necessary. In this way, it is possible to prevent local reductions in stiffness on the TI and TO sides. Thus, on the inner mounting side (TI), where wear is high, resistance to uneven wear can be improved, while on the outer mounting side (TO), where the load differential during tire rolling is high, steering stability performance on dry road surfaces can be improved.

[0041] In a further embodiment, at least one of the ratio Pi1 / Pin of the maximum pitch distance length Pi1 and the minimum pitch distance length Pin on the tire circumference on the inner vehicle mounting side TI and the ratio Po1 / Pon of the maximum pitch distance length Po1 and the minimum pitch distance length Pon on the tire circumference on the outer vehicle mounting side TO is preferably in a range of 1.20 to 2.00.

[0042] By setting at least one of the ratios Pi1 / Pin and Po1 / Pon to 1.20 or greater, the inner vehicle mounting side TI and the outer vehicle mounting side TO, to which the value is applied, can exhibit variations between a plurality of pitch distances. This makes it possible to disperse the sound frequency generated on sides TI and TO and to prevent sound amplification in the same frequency band. In this way, it is possible to reduce the sample noise measured inside the vehicle on the inner vehicle mounting side TI, and the sound performance (with respect to the sample noise) can be further improved. It is also possible to reduce the drive-by noise measured outside the vehicle on the outer vehicle mounting side TO, and the sound performance (with respect to the drive-by noise) can be further improved.

[0043] Furthermore, by setting at least one of the Pi1 / Pin and Po1 / Pon ratios to 2.00 or less, the variations between a plurality of pitch lengths on the inner mounting side TI and the outer mounting side TO, to which this value is applied, do not increase more than necessary. In this way, it is possible to prevent local reductions in stiffness on the TI and TO sides. Thus, on the inner mounting side TI, where wear is high, resistance to uneven wear can be further improved, while on the outer mounting side TO, where the load differential during tire rolling is high, steering stability on dry road surfaces can be improved. Examples of implementation

[0044] Pneumatic tires (a respective test tire) of an example of the prior art and embodiments 1 to 7 were each manufactured such that the tire size was set to 215 / 45R17 87W, with the tread pattern of Fig. 1 to Fig.3, wherein the number of pitch distances was 5, and wherein the pitch distance length ratio (pitch distance ratio I) on the inner vehicle assembly side, the pitch distance length ratio (pitch distance ratio O) on the outer vehicle assembly side, the ratio between maximum and minimum pitch distance length (size pitch distance ratio I) on the inner vehicle assembly side, the ratio between maximum and minimum pitch distance length (size pitch distance ratio O) on the outer vehicle assembly side,The size relationship (size relationship I of the number of pitch distances) between the number of maximum pitch distance lengths and the number of minimum pitch distance lengths on the inner vehicle assembly side and the size relationship (size relationship O of the number of pitch distances) between the number of maximum pitch distance lengths and the number of minimum pitch distance lengths on the outer vehicle assembly side exhibited the values ​​shown in Table 1.

[0045] Each of the tires produced in this manner was mounted on a 17x7J rim at an air pressure of 230 kPa and fitted to a sedan-type vehicle (front engine, front-wheel drive) with an engine displacement of 1800 cc, and the noise performance (relative to the reference noise) and steering stability performance were assessed. The results are shown in Table 1. (Noise output)

[0046] For noise performance (with respect to the sample noise), an overall value was measured (measured inside the vehicle) while driving at a speed of 100 km / h on a level road surface, and an index rating was performed, with the state-of-the-art example set as the reference (100). Higher index values ​​indicate better noise performance. (Steering stability performance)

[0047] To assess steering stability performance, a jury conducted a sensory evaluation while driving on dry road surfaces at a speed of 120 km / h. Based on the evaluation results, an index assessment was performed, with the state of the art serving as the reference (100). Higher index values ​​indicate better steering stability performance. [Table 1] State of the art example Example 1 Example 2 Example 3 Example 3 Example 4 Example 5 Example 6 Example 7 Division spacing ratio I Pi1 / Pi2 1,05 1,06 1,06 1,06 1,06 1,02 1,15 1,03 1,06 Pi2 / Pi3 1,05 1,10 1,10 1,10 1.10 1,03 1,18 1,10 1,10 Pi3 / Pi4 1,05 1,13 1,13 1,13 1,13 1,04 1,20 1,16 1,13 Pi4 / Pi5 1,05 1,16 1,16 1,16 1,16 1,05 1,24 1,22 1,16 Division spacing ratio O Po1 / Po2 1,05 1,16 1,10 1,16 1,16 1,06 1,26 1,16 1,22 Po2 / Po3 1,05 1,13 1,13 1,13 1,13 1,05 1,24 1,13 1,16 Po3 / Po4 1,05 1,10 1,10 1,10 1,10 1,04 1,20 1,10 1,10 Po4 / Po5 1,05 1,06 1,06 1,06 1,06 1,03 1,15 1,06 1,03 Size division distance ratio I(Pi1 / Pi5) 1,22 1,53 1,53 1,53 1,53 1,15 2,02 1,60 1,53 Size division distance ratio O(Po1 / Po5) 1,22 1,53 1,45 1,53 1,53 1,19 2,16 1,53 1,60 Size relationship I of the number of division intervals Pi1 < Pi5 Pi1 <Pi5 Pi1 <Pi5 Pi1 >Pi5 Pi1 <Pi5 Pi1 <Pi5 Pi1 <Pi5 Pi1 <Pi5 Pi1 <Pi5 Size relationship 0 of the number of division intervals Po1 <Po5 Po1 <Po5 Po1 <Po5 Po1 <Po5 Po1 >Po5 Po1 <Po5 Po1 <Po5 Po1 <Po5 Po1 <Po5 Noise power (with respect to the sample noise) 100 110 110 107 110 103 113 110 103 Steering stability performance 100 110 105 110 107 113 103 103 110

[0048] According to Table 1, it was determined that all pneumatic tires according to the invention of embodiments 1 and 3 to 7 within the technical scope of the present invention (where the pitch ratio I and the size relationships (size relationships of Pi1 / Pi2 and Pi4 / Pi5) between the pitch length ratio for the maximum pitch length and the pitch length ratio for the minimum pitch length on the inner vehicle mounting side TI are within a predetermined range) exhibited at least excellent noise performance compared to the pneumatic tire of the prior art example, which is not within the technical scope of the present invention.

[0049] The present invention includes the following aspects. (1) Pneumatic tire with a predetermined vehicle mounting direction, comprising, in a tire tread section, at least one main groove extending in a tire circumferential direction; and a plurality of inclined grooves intersecting the main groove, wherein, on an inner vehicle mounting side, in a region on an outer side in the tire width direction of the main groove, arranged on the outermost side in the tire width direction, pitch spacing lengths in the tire circumferential direction have pitch spacing variations comprising at least three pitch spacing lengths in a region formed by the inclined grooves and rib sections adjacent to the inclined grooves on a side in the tire circumferential direction, and where a number of pitch spacings is fixed to n and pitch spacing lengths Pi are each defined as Pi1, Pi2, Pi3,..., Pin in order of a largest pitch spacing length, relationships Pi1 / Pi2 ≤ Pi2 / Pi3 ≤...≤ Pin-1 / Pin and Pi1 / Pi2 < Pin-1 / Pin are satisfied. (2) Pneumatic tires according to point (1), wherein on an outer vehicle mounting side a region on the outside in the tire width direction of the main groove, which is arranged on the outermost side in the tire width direction, has pitch spacing lengths in the tire circumferential direction pitch spacing variations which include at least three pitch spacing lengths in a region formed from the inclined grooves and rib sections adjacent to the inclined grooves on one side in the tire circumferential direction, and where the number of pitch spacings is fixed to n and pitch spacing lengths Po are each defined as Po1, Po2, Po3,..., Pon in order of the largest pitch spacing length, relations Po1 / Po2 ≥ Po2 / Po3 ≥,..., ≥ Pon-1 / Pon and Po1 / Po2>Pon-1 / Pon are satisfied. (3) Pneumatic tires according to point (1) or (2), wherein on the inner vehicle mounting side the number of pitch intervals of pitch interval length Pi1 on the tire circumference is less than the number of pitch intervals of Pin on the tire circumference. (4) Pneumatic tires according to point (2) or (3), wherein on the outer vehicle mounting side the number of pitch intervals of pitch interval length Po1 on the tire circumference is less than the number of pitch intervals of Pon on the tire circumference. (5) Pneumatic tires according to one of points (2) to (4), wherein, if the number of pitch intervals is n, at least one of a pitch interval length ratio Pik - 1 / Pik, where k is at least one of natural numbers from 2 to n, is on the inner vehicle mounting side, and a pitch interval length ratio Pok - 1 / Pok, where k is at least one of natural numbers from 2 to n, is on the outer vehicle mounting side in a range of 1.05 to 1.20. (6) Pneumatic tires according to one of points (2) to (5), wherein at least one of a ratio Pi1 / Pin between the maximum pitch spacing length Pi1 and the minimum pitch spacing length Pin on the tire circumference on the inner vehicle mounting side and a ratio Po1 / Pon between the maximum pitch spacing length Po1 and the minimum pitch spacing length Pon on the tire circumference on the outer vehicle mounting side is in a range of 1.20 to 2.00.

Claims

[1] Pneumatic tires (1) with a predetermined vehicle mounting direction, comprising: in a tire tread section (10), at least one main groove (14, 14a, 14b, 14c, 14d) extending in a tire circumferential direction; and a plurality of inclined grooves (20, 22, 24, 26, 28) intersecting the main groove (14, 14a, 14b, 14c, 14d); on an inner vehicle mounting side (TI) in a region on an outer side in the tire width direction of the main groove (14, 14a, 14b, 14c, 14d) arranged on an outermost side in the tire width direction, pitch spacing lengths (Pi) which have pitch spacing variations in the tire circumference direction, including at least three pitch spacing lengths (Pi) in a region formed by the inclined grooves (20, 22, 24, 26, 28) and web sections adjacent to the inclined grooves (20, 22, 24, 26, 28) on a side in the tire circumference direction; and If a number of division intervals is fixed at n and division interval lengths (Pi) are defined as Pi1, Pi2, Pi3,..., Pin in order of a largest division interval length, then the relationships Pi1 / Pi2 ≤ Pi2 / Pi3 ≤,... ≤ Pin-1 / Pin and Pi1 / Pi2 < Pin-1 / Pin are satisfied, where on an outer vehicle mounting side (TO) in a region on an outer side in the tire width direction of the main groove (14, 14a, 14b, 14c, 14d) which is arranged on the outermost side in the tire width direction, pitch spacing lengths (Po) which have pitch spacing variations in the tire circumference direction, including at least three pitch spacing lengths (Po) in a region formed by the inclined grooves (20, 22, 24, 26, 28) and web sections adjacent to the inclined grooves (20, 22, 24, 26, 28) on a side in the tire circumference direction; and If a number of division intervals is fixed to n and division interval lengths (Po) are defined as Po1, Po2, Po3,..., Pon in order of a largest division interval length, then the relationships Po1 / Po2 ≥ Po2 / Po3 ≥,..., ≥ Pon-1 / Pon and Po1 / Po2 > Pon-1 / Pon are satisfied. [2] Pneumatic tire (1) according to claim 1, wherein on the inner vehicle mounting side (TI) a number of pitch intervals of pitch interval length Pi1 on a tire circumference is smaller than a number of pitch intervals of Pin on the tire circumference. [3] Pneumatic tire (1) according to claim 1 or 2, wherein on the outer vehicle mounting side (TO) a number of pitch intervals of pitch interval length Po1 on the tire circumference is smaller than a number of pitch intervals of Pon on the tire circumference. [4] Pneumatic tire (1) according to one of claims 2 or 3, wherein if the number of pitch intervals n is, at least one of a pitch interval length ratio Pik - 1 / Pik, where k is at least one of natural numbers from 2 to n, on the inner vehicle mounting side (TI), and a pitch interval length ratio Pok - 1 / Pok, where k is at least one of natural numbers from 2 to n, on the outer vehicle mounting side (TO) is in a range of 1.05 to 1.

20. [5] Pneumatic tire (1) according to one of claims 2 to 4, wherein at least one of a ratio Pi1 / Pin between the maximum pitch distance length Pi1 and the minimum pitch distance length Pin on the tire circumference on the inner vehicle mounting side (TI) and a ratio Po1 / Pon between the maximum pitch distance length Po1 and the minimum pitch distance length Pon on the tire circumference on the outer vehicle mounting side (TO) is in a range of 1.20 to 2.00.

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