pneumatic tires

Abstract

To provide a pneumatic tire that can improve uniformity while maintaining cut resistance of the sidewall. [Solution] The pneumatic tire 1 includes a first side block 11 arranged on a first tire circumferential line Y1 and a plurality of second side blocks 12 arranged on a second tire circumferential line Y2 in the first side portion 3A. The first side block 11 and the second side block 12 are spaced apart from each other in the tire circumferential direction and overlap in the tire radial direction and in the tire circumferential direction. The overlapping length Ha in the tire radial direction between the first side block 11 and the second side block 12 is 30% to 60% of the maximum length H2 of the second side block 12 in the tire radial direction. The overlapping length La in the tire circumferential direction between the first side block 11 and the second side block 12 is 5% or more of the maximum length La of the second side block 12 in the tire circumferential direction.

Description

Technical Field

[0001] The present invention relates to pneumatic tires.

Background Art

[0002] Patent Document 1 below describes a pneumatic tire having a pair of sidewall portions extending radially inward in the tire radius direction from both ends of the tread portion. At least one of the pair of sidewall portions is provided with a plurality of side protectors that bulge outward in the tire axial direction and recesses that are recessed between the adjacent side protectors in the tire circumferential direction.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] Generally, since side protectors are provided to improve cut resistance and mud performance, in recent years, they tend to be enlarged and densified. However, in such tires, there is a problem that local weight concentration and rigidity concentration occur in the side portion, deteriorating uniformity.

[0005] The present invention has been devised in view of the above actual situation, and the main object thereof is to provide a pneumatic tire that can improve uniformity while maintaining the cut resistance of the side portion.

Means for Solving the Problems

[0006] A pneumatic tire comprising a tread portion and a first side portion connected to the tread end of the tread portion, wherein the first side portion has a plurality of side blocks arranged in the tire circumferential direction, each side block projecting outward in the tire axial direction from a side reference plane, the plurality of side blocks comprising a plurality of first side blocks arranged on a first tire circumferential line and a plurality of second side blocks arranged on a second tire circumferential line located radially inward from the first tire circumferential line, the first side blocks and the second side blocks being spaced apart from each other in the tire circumferential direction, one of the first side blocks and one of the second side blocks being adjacent to each other in the tire circumferential direction overlapping in the tire radial direction and in the tire circumferential direction, the overlapping length of the adjacent first side block and second side block in the tire radial direction being 30% to 60% of the maximum length of the second side block in the tire radial direction, and the overlapping length of the adjacent first side block and second side block in the tire circumferential direction being 5% or more of the maximum length of the second side block in the tire circumferential direction. [Effects of the Invention]

[0007] By adopting the above configuration, the pneumatic tire of the present invention can improve uniformity while maintaining cut resistance of the sidewall. [Brief explanation of the drawing]

[0008] [Figure 1] This is a meridian cross-sectional view of the right half of a pneumatic tire according to one embodiment of the present invention. [Figure 2] Figure 1 is a cross-sectional perspective view of the tire. [Figure 3] Figure 1 is a side view of the tire. [Figure 4] This is an enlarged view of Figure 3. [Figure 5] This is a magnified view of the tire in Figure 1. [Figure 6] This is an enlarged view of Figure 3. [Figure 7] This is an enlarged view of Figure 3. [Figure 8]This is a cross-sectional perspective view showing the first side block of Example 7. [Modes for carrying out the invention]

[0009] Hereinafter, one embodiment of the present invention will be described with reference to the drawings. The drawings contain exaggerations and representations that differ from the actual structural dimensional ratios in order to aid in understanding the present invention. Furthermore, where there are multiple embodiments, the same or common elements are denoted by the same reference numerals throughout the specification, and redundant descriptions are omitted.

[0010] Figure 1 is a meridian cross-sectional view of the right half of a pneumatic tire (hereinafter sometimes referred to as "tire") 1, which represents one embodiment of the present invention. In Figure 1, a preferred embodiment shows a tire for a passenger car (particularly for a large SUV). However, the present invention may also be applied to tires for light trucks, trucks, and buses. Figure 1 shows a tire 1 in its normal state.

[0011] The aforementioned "normal state" refers to the unloaded state in the case of pneumatic tires for which various standards are defined, where the tire is mounted on a standard rim (not shown) and adjusted to the standard internal pressure. In the case of tires for which various standards are not defined, the aforementioned normal state means the standard operating state according to the intended use of the tire, where it is not mounted on a vehicle and is unloaded. In this specification, unless otherwise specified, the dimensions of each part of the tire are values ​​measured in the aforementioned normal state. Furthermore, for components that cannot be measured in the aforementioned normal state (for example, the internal material of the tire), the values ​​are measured with the tire in a state that approximates the aforementioned normal state as much as possible.

[0012] A "standard rim" is the rim specified for each tire within the standard system that the tire is based on. For example, it is the "standard rim" for JATMA, the "Design Rim" for TRA, and the "Measuring Rim" for ETRTO.

[0013] "Regular internal pressure" refers to the air pressure specified for each tire by each standard within the tire standard system, including the standard on which the tire is based. For JATMA, it is the "maximum air pressure," for TRA, it is the maximum value listed in the table "TIRE LOAD LIMITS AT VARIOUSCOLD INFLATION PRESSURES," and for ETRTO, it is the "INFLATION PRESSURE."

[0014] The tire 1 includes a tread portion 2 and a first side portion 3A connected to the tread edge Te of the tread portion 2. The tire 1 also includes a first bead portion 4A connected to the radially inward side of the first side portion 3A, a second side portion (not shown) on the opposite side from the first side portion 3A across the tire equator C, and a second bead portion (not shown) connected to the second side portion. In this embodiment, the second side portion has the same configuration as the first side portion 3A. However, the second side portion may have a different configuration from the first side portion 3A.

[0015] The tread edge Te, in the case of a pneumatic tire, is the outermost axial position of the tire in contact with the surface when the tire is under normal load. The normal load condition is when the tire is subjected to a normal load and made contact with the surface at a camber angle of 0°. The "normal load" is the load specified for each tire in the standards system, including the standard on which the tire is based. For JATMA, it is the "maximum load capacity," for TRA, it is the maximum value listed in the table "TIRE LOAD LIMITS AT VARIOUS COLD INFLATION PRESSURES," and for ETRTO, it is the "LOAD CAPACITY."

[0016] Figure 2 is a cross-sectional perspective view of the tire 1 shown in Figure 1. Figure 2 shows the area near the first side portion 3A. As shown in Figures 1 and 2, the first side portion 3A has multiple side blocks 10 arranged in the circumferential direction of the tire, which protrude outward from the side reference surface 3k in the tire axial direction. The side blocks 10 provide basic cut resistance.

[0017] The plurality of side blocks 10 includes a plurality of first side blocks 11 arranged on the first tire circumferential line Y1 and a plurality of second side blocks 12 arranged on the second tire circumferential line Y2 inside the tire in the radial direction with respect to the first tire circumferential line Y1. The first side blocks 11 and the second side blocks 12 are spaced apart from each other in the tire circumferential direction.

[0018] FIG. 3 is a side view of the tire 1 and a front view of the first side portion 3A. FIG. 4 is an enlarged view of FIG. 3. As shown in FIGS. 3 and 4, one of the first side blocks 11 and one of the second side blocks 12 adjacent to each other in the tire circumferential direction overlap in the tire radial direction and the tire circumferential direction. Further, the overlapping length Ha in the tire radial direction between the adjacent first side block 11 and second side block 12 is 30% to 60% of the maximum length H2 in the tire radial direction of the second side block 12. Since the overlapping length Ha is 30% or more of the maximum length H2 of the second side block 12, the first side block 11 and the second side block 12 can be surely overlapped in the tire radial direction, and the cut resistance of the first side portion 3A is maintained high. In order to further exhibit such an effect, the overlapping length Ha is preferably 35% or more, more preferably 40% or more of the maximum length H2 of the second side block 12. Since the overlapping length Ha is 60% or less of the maximum length H2 of the second side block 12, an excessive increase in mass is suppressed, and the mass bias of the first side portion 3A can be suppressed. In order to further exhibit such an effect, the overlapping length Ha is preferably 55% or less, more preferably 50% or less of the maximum length H2 of the second side block 12.

[0019] Also, the overlapping length La in the tire circumferential direction between the adjacent first side block 11 and second side block 12 is 5% or more of the maximum length L2 in the tire circumferential direction of the second side block 12. Thereby, the cut resistance of the first side portion 3A is maintained at a high level. In order to further exert such an effect, the overlapping length La is preferably 10% or more of the maximum length L2 of the second side block 12, and more preferably 15% or more. By having such a configuration, the tire 1 of the present embodiment can improve uniformity while maintaining the cut resistance of the first side portion 3A.

[0020] If the overlapping length La is excessively large, there is a possibility that the bias of the mass of the first side portion 3A becomes large. For this reason, the overlapping length La is preferably 25% or less of the maximum length L2 of the second side block 12, more preferably 15% or less, and even more preferably 10% or less.

[0021] The overlap length Ha in the tire radial direction is the tire radial separation distance between the outer end 12e of the second side block 12 and the inner end 11i of the first side block 11 in the tire radial direction. The maximum length H2 of the second side block 12 is the tire radial separation distance between the inner end 12i and the outer end 12e of the second side block 12 in the tire radial direction. The overlap length La in the tire circumferential direction is the tire circumferential separation distance on the outer end 12t of the second side block 12 on the second tire circumferential direction f2 (adjacent first side block 11) side between tire radial lines r1 and tire radial lines r2. Tire radial line r1 is the tire radial line passing through the outer end 11u of the first side block 11 on the first tire circumferential direction f1 (adjacent second side block 12) side. Tire radial line r2 is the tire radial line passing through the outer end 12t of the second side block 12. The maximum length L2 of the second side block 12 is the circumferential separation distance between the tire radial line r2 and the tire radial line r3, passing through either the outer end 12u or the outer end 12t, which is located on the inner side in the tire radial direction. The outer end 12u is the end of the second side block 12 on the first tire circumferential direction f1 side. The tire radial line r3 is the tire radial line passing through the outer end 12u of the second side block 12. In this embodiment, the outer end 12t and the outer end 12u are positioned at the same location in the tire radial direction. In Figure 4, the first tire circumferential direction f1 is clockwise, and the second tire circumferential direction f2 is counterclockwise. Note that the first tire circumferential direction f1 and the second tire circumferential direction f2 are not limited to this embodiment.

[0022] As shown in Figures 2 and 3, the tread portion 2 has a plurality of shoulder lateral grooves 6 extending in the tire axial direction on the first side portion 3A side. The shoulder lateral grooves 6 extend inward and outward in the tire axial direction, straddling the tread end Te. The shoulder lateral grooves 6 consist of first shoulder lateral grooves 6A and second shoulder lateral grooves 6B, which are alternately arranged in the tire circumferential direction. The first shoulder lateral grooves 6A terminate, for example, so as to connect with the side block 10. The second shoulder lateral grooves 6B terminate at a distance from the side block 10.

[0023] Furthermore, the tread portion 2 includes shoulder blocks 7 arranged between adjacent shoulder lateral grooves 6 in the circumferential direction of the tire. The shoulder blocks 7 are formed such that first shoulder blocks 7A and second shoulder blocks 7B are arranged alternately in the circumferential direction of the tire. The first shoulder block 7A includes a first tread end T1. The second shoulder block 7B includes a second tread end T2 located inward in the axial direction of the tire from the first tread end T1. Thus, the tread end Te of this embodiment is formed such that the first tread end T1 and the second tread end T2 are arranged alternately in the circumferential direction of the tire.

[0024] The shoulder block 7 includes a contact surface 8 extending inward in the tire axial direction from the tread edge Te, and a buttress surface 9 extending outward in the tire axial direction from the tread edge Te. The contact surface 8 is the surface that contacts the plane under the normal load condition. The buttress surface 9 is the surface that is connected to the tread edge Te and does not contact the plane. The contact surface 8 extends, for example, parallel to the groove bottom 6s of the shoulder lateral groove 6 (shown in Figure 1).

[0025] Figure 5 is an enlarged view of tire 1 in Figure 1. Figure 5 shows the area near the tread edge Te. As shown in Figure 5, in the tire meridian section, the buttress surface 9A of the first shoulder block 7A is formed by a single surface extending linearly or in a convex arc outward in the tire axial direction. The buttress surface 9A is connected, for example, to the first tread edge T1. In the tire meridian section, the buttress surface 9B of the second shoulder block 7B is formed by two surfaces consisting of a first surface portion 13a and a second surface portion 13b. The first surface portion 13a is connected to the second tread edge T2 and extends in a convex arc inward in the tire axial direction. The second surface portion 13b is connected to the first surface portion 13a and extends linearly or in a convex arc outward in the tire axial direction. The first surface portion 13a and the second surface portion 13b are connected via a bend. The buttress surface 9A of the first shoulder block 7A and the buttress surface 9B of the second shoulder block 7B are not limited to this configuration.

[0026] In this specification, the side reference surface 3k is the outer surface of the first side portion 3A that extends smoothly, excluding irregularities such as spews, bulges, dents, and the marking portion K. The side reference surface 3k is formed, for example, by a convex arc outward in the tire axial direction. The side reference surface 3k is formed to connect smoothly with, for example, the groove bottom 6s of the shoulder lateral groove 6. In this embodiment, the side reference surface 3k connects smoothly with the groove bottom 6s of the second shoulder lateral groove 6B. In this embodiment, the marking portion K is provided on the inside of the side block 10 in the tire radial direction.

[0027] As shown in Figure 2, the first side block 11 and the second side block 12 are arranged, for example, at equal pitches in the circumferential direction of the tire. This further reduces localized mass unevenness in the first side portion 3A. Alternatively, the first side block 11 and the second side block 12 may be arranged at different pitches in the circumferential direction of the tire.

[0028] The midpoint 11c of each first side block 11 in the tire radial direction is aligned at the same height in the tire radial direction. Similarly, the midpoint 12c of each second side block 12 in the tire radial direction is aligned at the same height in the tire radial direction. Furthermore, the midpoint 11c of the first side block 11 is located further outward in the tire radial direction than the midpoint 12c of the second side block 12. Also, in a side view of the tire, the centroid 11s of the first side block 11 (shown in Figure 3) is located further outward in the tire radial direction than the centroid 12s of the second side block 12.

[0029] In this embodiment, the outer end 11e of the first side block 11 in the tire radial direction is located further outward in the tire radial direction than the outer end 12e of the second side block 12 in the tire radial direction. Also, the inner end 11i of the first side block 11 in the tire radial direction is located further outward in the tire radial direction than the inner end 12i of the second side block 12 in the tire radial direction. The inner end 11i of the first side block 11 in the tire radial direction is located further inward in the tire radial direction than the outer end 12e of the second side block 12 in the tire radial direction.

[0030] As shown in Figure 3, the first side block 11 is connected to the shoulder block 7. The first side block 11 is connected to the first shoulder block 7A and the second shoulder block 7B. The first side block 11 is smoothly connected to the buttress surface 9A of the first shoulder block 7A and to the second surface portion 13b of the second shoulder block 7B. In Figure 3, the boundary B1 between the first side block 11 and the shoulder block 7 is shown by a dashed line. In this embodiment, the second side block 12 is positioned without being connected to the shoulder block 7.

[0031] In an embodiment where the side block 10 and the shoulder block 7 are connected, the boundary B1 between the side block 10 and the shoulder block 7 is defined by a vulcanizing mold (not shown). The vulcanizing mold vulcanizes the green tire placed inside to form the tire 1. The vulcanizing mold includes a tread mold for forming the tread portion 2 and a side mold (not shown) for forming the first side portion 3A and the second side portion. The tread mold and the side mold are joined at a joint surface during the vulcanization molding process. The boundary B1 is defined by the position of the joint surface.

[0032] In this embodiment, the first side block 11 has an inverse tapered shape, with its circumferential length increasing towards the outward side in the tire radial direction. The second side block 12 has a tapered shape, for example, with its circumferential length decreasing towards the outward side in the tire radial direction. More specifically, each of the first side block 11 and the second side block 12 is, for example, an isosceles trapezoid shape. The longer side of the first side block 11 is located further outward in the tire radial direction than its shorter side. The longer side of the second side block 12 is located further inward in the tire radial direction than its shorter side. Such a side block 10 can suppress the increase in mass of the overlapping portion, thereby further improving uniformity.

[0033] The shape of the side block 10 is not limited to this configuration. For example, the first side block 11 may be inverted triangular in shape, and the second side block 12 may be triangular in shape. More specifically, the first side block 11 may be an isosceles triangle (including an equilateral triangle) with its base located outside the vertex in the tire radial direction. Similarly, the second side block 12 may be an isosceles triangle (including an equilateral triangle) with its base located inside the vertex in the tire radial direction. Furthermore, the side block 10 may have other polygonal shapes and is not limited to polygons.

[0034] Figure 6 is an enlarged view of Figure 3. As shown in Figure 6, the first side block 11 overlaps in the circumferential direction of the tire with the first projection region R1, which is obtained by projecting the first shoulder lateral groove 6A radially inward of the tire. Similarly, the second side block 12 overlaps in the circumferential direction of the tire with the second projection region R2, which is obtained by projecting the second shoulder lateral groove 6B radially inward of the tire. As a result, the side blocks 10 are positioned where the mass of the first side portion 3A is small (where the shoulder lateral groove 6 is located), further reducing the localized bias in the mass of the first side portion 3A. Therefore, uniformity is further improved.

[0035] The first projection region R1 is the region within two tire radial lines r6 obtained by translating the tire radial line r5 to each intersection point k1 where the pair of groove edges 6e of the first shoulder lateral groove 6A intersect with the tread edge Te. The tire radial line r5 is the tire radial line passing through the intersection point k2 of the groove width centerline 6c1 of the first shoulder lateral groove 6A and the tire circumferential line y1 passing through the second tread edge T2. The second projection region R2 is the region within two tire radial lines r8 obtained by translating the tire radial line r7 to each intersection point k3 where the pair of groove edges 6i of the second shoulder lateral groove 6B intersect with the tread edge Te. The tire radial line r7 is the tire radial line passing through the intersection point k4 of the groove width centerline 6c2 of the second shoulder lateral groove 6B and the tire circumferential line y2 passing through the second tread edge T2.

[0036] In a side view of the tire, it is desirable that the centroid 11s of the first side block 11 overlaps with the first projection region R1 in the tire circumferential direction. Furthermore, it is even more desirable that the centroid 11s of the first side block 11 lies on the tire radial line r5 in a side view of the tire. Furthermore, it is desirable that the centroid 12s of the second side block 12 overlaps with the second projection region R2 in the tire circumferential direction. Furthermore, it is even more desirable that the centroid 12s of the second side block 12 lies on the tire radial line r7 in a side view of the tire. This further improves uniformity.

[0037] It is desirable that the volume V2 of the portion of the second side block 12 that protrudes from the side reference surface 3k is smaller than the volume V1 of the portion of the first side block 11 that protrudes from the side reference surface 3k. This reduces the mass imbalance between the outer portion in the tire radial direction with a relatively large circumference (e.g., near the first tire circumferential line Y1) and the inner portion in the tire radial direction with a relatively small circumference (e.g., near the second tire circumferential line Y2). To exert this effect more effectively, it is desirable that the volume V2 of the second side block 12 be 20% or more of the volume V1 of the first side block 11, more preferably 30% or more, more preferably 50% or less, and more preferably 40% or less.

[0038] As shown in Figures 2 and 5, the first side block 11 includes a first portion 11A that protrudes from the side reference surface 3k at a first height h1, and a second portion 11B that protrudes at a second height h2 greater than the first height h1. The first side block 11, located on the outer side in the radial direction of the tire, is a side block 10 that is more susceptible to cuts than the second side block 12. For this reason, the first side block 11 having the second portion 11B can have improved cut resistance.

[0039] The first height h1 and the second height h2 decrease toward the inside in the radial direction of the tire. This allows for a balance between cut resistance and uniformity. Although not particularly limited, the first height h1 is preferably 5 mm or more, more preferably 6 mm or more, preferably 9 mm or less, and more preferably 8 mm or less.

[0040] The difference (h2-h1) between the second height h2 and the first height h1 is preferably 60% or more of the first height h1, more preferably 70% or more, preferably 100% or less, and more preferably 90% or less. Since the difference (h2-h1) is 60% or more of the first height h1, high cut resistance can be maintained. Since the difference (h2-h1) is 100% or less of the first height h1, an excessive increase in the mass of the first side portion 3A can be suppressed. The first height h1 and the second height h2 are specified at the same position in the radial direction of the tire.

[0041] As shown in Figure 6, in a side view of the tire, the centroid 11Bs of the second portion 11B is located radially outward from the centroid 11s of the first side block 11. Thus, because the second portion 11B is located radially outward from the first side block 11, its cut resistance can be further improved.

[0042] As shown in Figure 5, the second side block 12 is formed by a third portion 14 that protrudes from the side reference surface 3k at a third height h3. The third height h3 also decreases toward the inside in the tire radial direction. This makes it possible to achieve both cut resistance and uniformity. Note that the third height h3 may be the same height both inside and outside in the tire radial direction.

[0043] At the same position in the tire radial direction, the third height h3 is smaller than the first height h1. Such a second side block 12 achieves both uniformity and cut resistance.

[0044] Figure 7 is an enlarged view of Figure 3. As shown in Figure 7, the first side block 11 includes a pair of first outer edges 18 positioned at both ends in the circumferential direction of the tire and extending in the radial direction of the tire. Each of the pair of first outer edges 18 includes an inner end 18i in the radial direction of the tire. The second side block 12 includes a pair of second outer edges 19 positioned at both ends in the circumferential direction of the tire and extending in the radial direction of the tire. Each of the pair of second outer edges 19 includes an inner end 19i in the radial direction of the tire. The pair of first outer edges 18 and the pair of second outer edges 19 each extend linearly and inclined with respect to the radial direction of the tire.

[0045] Furthermore, the angle θ1 between each of the pair of first outer edges 18 and the tire radial line ra passing through each inner end 18i is preferably 5 degrees or more, more preferably 10 degrees or more, preferably 30 degrees or less, and even more preferably 25 degrees or less. This suppresses excessive mass increase of the first side block 11 and, consequently, reduces mass imbalance, thereby improving uniformity, particularly dynamic balance (DB). From a similar viewpoint, the angle θ2 between each of the pair of second outer edges 19 and the tire radial line rb passing through each inner end 19i is preferably 5 degrees or more, more preferably 10 degrees or more, preferably 30 degrees or less, and even more preferably 25 degrees or less. In this embodiment, the first outer edge 18 and the second outer edge 19 extend parallel to each other.

[0046] The second part 11B includes a pair of third outer edges 20 positioned at both ends in the circumferential direction of the tire and extending in the radial direction of the tire. Each of the pair of third outer edges 20 includes an inner end 20i in the radial direction of the tire. The angle θ3 between each of the pair of third outer edges 20 and the tire radial line rc passing through each inner end 20i is preferably 5 degrees or more, more preferably 10 degrees or more, preferably 30 degrees or less, and more preferably 25 degrees or less. This suppresses the increase in mass of the second part and, consequently, improves uniformity. In this embodiment, the first outer edge 18 and the third outer edge 20 extend parallel to each other.

[0047] As shown in Figures 2 and 7, each of the multiple shoulder lateral grooves 6 includes a protector 30 that extends along the longitudinal direction of the shoulder lateral groove 6 and has a raised groove bottom 6s. The protector 30 is positioned on the groove width centerline 6c of the shoulder lateral groove 6. The protector 30 includes a first protector 30A provided in the first shoulder lateral groove 6A and a second protector 30B provided in the second shoulder lateral groove 6B. The first protector 30A extends toward the first side block 11 and terminates without connecting to the first side block 11. The second protector 30B extends toward the second side block 12 and terminates without connecting to the second side block 12. The outer end 30a of the first protector 30A in the tire axial direction is located outward from the first tread edge T1 in the tire axial direction. The outer end 30b of the second protector 30B in the tire axial direction is located radially inward from the outer end 25e of the second part 11B in the tire radial direction. Also, the outer end 30b of the second protector 30B in the tire axial direction is located radially outward from the inner end 25i of the second part 11B in the tire radial direction. Such a second protector 20B helps to maintain high cut resistance.

[0048] Although particularly preferred embodiments of the present invention have been described in detail above, the present invention is not limited to the illustrated embodiments and can be implemented in various modified forms. [Examples]

[0049] A pneumatic tire having the basic structure shown in Figure 1 and the basic shape of the first side section shown in Figure 2 was prototyped based on the specifications in Tables 1 and 2. Each test tire was then tested for cut resistance and uniformity. The common specifications and test methods for each test tire are as follows. Tire size: 35×12.50R17 Internal pressure: 450kPa The "Presence or absence of connection between blocks" in the table refers to the connection between the first side block and the shoulder block. The volume of the first side block is the same in all examples and comparative examples. Figure 8 shows an embodiment of the first side block of Example 7.

[0050] <Cut resistance> Each test tire was fitted to all four wheels of a 3500cc four-wheel-drive vehicle. After a test driver drove approximately 1500km on rocky terrain including rocks and rubble, the cut resistance was evaluated based on the depth and length of cuts that occurred on the outer surface of the first sidewall. The results are shown on a scale where Comparative Example 1 is rated at 100. A higher number indicates smaller cuts that affect tire performance and superior cut resistance.

[0051] <Uniformity> Using a tire uniformity tester, radial force variation (RFV) and dynamic balance (DB) were measured under the following conditions. The results were indexed with the measured value for Comparative Example 1 set to 100, and other measured values ​​were indexed such that a higher value indicates better performance. The test results are shown in Tables 1 and 2. Load: 8.0kN Speed: 10km / h

[0052] [Table 1]

[0053] The test results show that the example tire exhibits improved uniformity compared to the comparative example tire, while maintaining cut resistance.

[0054] [Note] The present invention includes the following embodiments.

[0055] [Invention 1] The tread section and, A pneumatic tire including a first side portion connected to the tread edge of the tread portion, The first side portion has a plurality of side blocks arranged in the circumferential direction of the tire, which protrude outward from the side reference surface in the tire axial direction. The plurality of side blocks include a plurality of first side blocks arranged on a first tire circumferential line and a plurality of second side blocks arranged on a second tire circumferential line located radially inward from the first tire circumferential line. The first side block and the second side block are spaced apart from each other in the circumferential direction of the tire. One of the first side blocks and one of the second side blocks, which are adjacent to each other in the circumferential direction of the tire, overlap in the radial direction and the circumferential direction of the tire. The overlapping length in the tire radial direction between the adjacent first side block and the second side block is 30% to 60% of the maximum length of the second side block in the tire radial direction. The overlapping length in the tire circumferential direction between the adjacent first side block and the second side block is 5% or more of the maximum length of the second side block in the tire circumferential direction. Pneumatic tires. [Invention 2] Multiple shoulder lateral grooves extending in the tire axial direction are formed on the first side portion of the tread portion. The aforementioned multiple shoulder lateral grooves are arranged such that the first shoulder lateral groove and the second shoulder lateral groove are alternately arranged in the circumferential direction of the tire. The first side block overlaps with the first projected region obtained by projecting the first shoulder lateral groove radially inward of the tire in the tire circumferential direction. The pneumatic tire according to the present invention, wherein the second side block overlaps in the circumferential direction of the tire with a second projected region obtained by projecting the second shoulder lateral groove radially inward of the tire. [Invention 3] In a side view of the tire, the centroid of the first side block overlaps with the first projection region in the circumferential direction of the tire. The pneumatic tire according to the present invention, wherein the centroid of the second side block overlaps with the second projection region in the tire circumferential direction. [4th Invention] The pneumatic tire according to any one of inventions 1 to 3, wherein the volume of the portion of the second side block protruding from the side reference surface is 20% to 50% of the volume of the portion of the first side block protruding from the side reference surface. [5th ​​Invention] The pneumatic tire according to any one of inventions 1 to 4, wherein the first side block includes a first portion that protrudes from the side reference surface at a first height h1 and a second portion that protrudes at a second height h2 greater than the first height h1. [Invention 6] The first side block is positioned at both ends in the circumferential direction of the tire and includes a pair of first outer edges extending in the radial direction of the tire. The angle between each of the pair of first outer edges and the tire radial line passing through the inner ends of the pair of first outer edges in the tire radial direction is 5 to 30 degrees. The second side block is positioned at both ends in the circumferential direction of the tire and includes a pair of second outer edges extending in the radial direction of the tire. The pneumatic tire according to any one of inventions 1 to 5, wherein the angle between each of the pair of second outer edges and the tire radial line passing through the inner ends of the pair of second outer edges in the tire radial direction is 5 to 30 degrees. [7th Invention] The pneumatic tire according to invention 2 or 3, wherein each of the plurality of shoulder lateral grooves includes a protector that extends along the longitudinal direction of the shoulder lateral groove and has a raised groove bottom. [8th Invention] The tread portion includes shoulder blocks arranged between adjacent shoulder lateral grooves in the circumferential direction of the tire. The first side block is connected to the shoulder block, and the pneumatic tire is as described in invention 2 or 3. [Invention 9] The first side block has an inverse tapered shape, with its circumferential length increasing towards the radially outward direction of the tire. The pneumatic tire according to any one of inventions 1 to 8, wherein the second side block has a tapered shape in which the circumferential length decreases toward the radially outward direction of the tire. [Explanation of symbols]

[0056] 1. Pneumatic tire 3A First side section 11. First side block 12. Second side block Y1 First tire circumferential line Y2 Second tire circumferential line H2 Maximum length of the tire radial direction of the second side block Ha Overlap length in the radial direction of the tire between the first side block and the second side block L2 Maximum length of the second side block in the tire circumferential direction La The overlapping length in the tire circumferential direction between the first side block and the second side block.

Claims

1. The tread section and, A pneumatic tire including a first side portion connected to the tread edge of the tread portion, The first side portion has a plurality of side blocks arranged in the circumferential direction of the tire, which protrude outward from the side reference surface in the tire axial direction. The plurality of side blocks include a plurality of first side blocks arranged on a first tire circumferential line and a plurality of second side blocks arranged on a second tire circumferential line located radially inward from the first tire circumferential line. The first side block and the second side block are spaced apart from each other in the circumferential direction of the tire. One of the first side blocks and one of the second side blocks, which are adjacent to each other in the circumferential direction of the tire, overlap in the radial direction and the circumferential direction of the tire. The overlapping length in the tire radial direction between the adjacent first side block and the second side block is 30% to 60% of the maximum length of the second side block in the tire radial direction. The overlapping length in the tire circumferential direction between the adjacent first side block and the second side block is 5% or more of the maximum length of the second side block in the tire circumferential direction. Pneumatic tires.

2. Multiple shoulder lateral grooves extending in the tire axial direction are formed on the first side portion of the tread portion. The aforementioned plurality of shoulder lateral grooves are arranged such that the first shoulder lateral groove and the second shoulder lateral groove are alternately arranged in the circumferential direction of the tire. The first side block overlaps with the first projected region obtained by projecting the first shoulder lateral groove radially inward of the tire in the tire circumferential direction. The pneumatic tire according to claim 1, wherein the second side block overlaps in the circumferential direction of the tire with a second projected region obtained by projecting the second shoulder lateral groove radially inward of the tire.

3. In a side view of the tire, the centroid of the first side block overlaps with the first projection region in the circumferential direction of the tire. The pneumatic tire according to claim 2, wherein the centroid of the second side block overlaps with the second projection region in the tire circumferential direction.

4. The pneumatic tire according to any one of claims 1 to 3, wherein the volume of the portion of the second side block that protrudes from the side reference surface is 20% to 50% of the volume of the portion of the first side block that protrudes from the side reference surface.

5. The pneumatic tire according to any one of claims 1 to 3, wherein the first side block includes a first portion that protrudes from the side reference surface at a first height h1 and a second portion that protrudes at a second height h2 greater than the first height h1.

6. The first side block is positioned at both ends in the circumferential direction of the tire and includes a pair of first outer edges extending in the radial direction of the tire. The angle between each of the pair of first outer edges and the tire radial line passing through the inner ends of the pair of first outer edges in the tire radial direction is 5 to 30 degrees. The second side block is positioned at both ends in the circumferential direction of the tire and includes a pair of second outer edges extending in the radial direction of the tire. The pneumatic tire according to any one of claims 1 to 3, wherein the angle between each of the pair of second outer edges and the tire radial line passing through the inner ends of the pair of second outer edges in the tire radial direction is 5 to 30 degrees.

7. The pneumatic tire according to claim 2, wherein each of the plurality of shoulder lateral grooves includes a protector that extends along the longitudinal direction of the shoulder lateral groove and has a raised groove bottom.

8. The tread portion includes shoulder blocks arranged between adjacent shoulder lateral grooves in the circumferential direction of the tire. The first side block is connected to the shoulder block, as described in claim 2, for a pneumatic tire.

9. The first side block has an inverse tapered shape, with its circumferential length increasing towards the radially outward direction of the tire. The pneumatic tire according to any one of claims 1 to 3, wherein the second side block has a tapered shape in which the circumferential length decreases toward the radially outward direction of the tire.

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