R e i f e n

Abstract

A tire is provided that ensures excellent block resistance and provides improved driving performance on poor roads. A shoulder area of ​​a tread section (1) is provided with a plurality of shoulder blocks (12). A side area adjacent to an outer side in a tire width direction of the shoulder area is provided with a plurality of side blocks (13). A side block (13) is located at a position on the outer side in the tire width direction of a block group consisting of two or more shoulder blocks (12) that are adjacent in a tire circumference direction.One side surface of each of the shoulder blocks (12) is provided with a curved recessed section (20) consisting of a first recessed section (21) and a second recessed section (22) extending along the tire circumference, and a third recessed section (23) connecting the first recessed section (21) and the second recessed section (22) and extending obliquely to the tire circumference. One surface of each of the side blocks (13) is provided with a curved protruding section consisting of a first protruding section (31) and a second protruding section (32) extending along the tire circumference, and a third protruding section (33) connecting the first protruding section (31) and the second protruding section (32) and extending obliquely to the tire circumference.

Description

Technical field

[0001] The present invention relates to a tire intended for driving on unpaved roads or the like, and in particular to a tire that can ensure reliable block resistance and furthermore provide improved driving performance on poor roads. State of the art

[0002] Tires (e.g., all-terrain tires and off-road tires) intended for driving on unpaved roads (e.g., uneven terrain, muddy terrain, sandy terrain, and rocky terrain) in addition to paved road surfaces are expected to provide excellent driving performance on a variety of road surfaces and, in particular, excellent off-road driving performance (driving performance on poor roads) in rough terrain.In such tires, not only the tread section that comes into contact with the road surface on paved roads, but also the sidewalls (areas between the tread section and the sidewall sections) that can come into contact with mud, snow, sand, stones, rocks, and the like (hereinafter collectively referred to as "mud and the like") on unpaved roads, are provided with irregularities (sideblocks and the like) to trap mud and the like and improve traction (see, for example, patent documents 1 and 2). In recent years, the performance requirements for tires have increased, and further improvements in driving performance on poor roads have become necessary.Since the sidewall liner can be easily damaged by stones, rocks, foreign objects, and the like on unpaved (poor) roads, its durability must also be ensured. Therefore, it is necessary to improve driving performance on poor roads while simultaneously ensuring durability (especially liner resistance) and providing both performance levels in a highly compatible manner. List of literature on patent literature Patent Document 1: JP 2017-124733 A Patent document 2: JP 2020-044882 A Brief description of the invention: Technical problem

[0003] One object of the present invention is to provide a tire that can provide excellent block resistance and also improved driving performance on poor roads. Solution to the problem

[0004] To achieve the problem described above, a tire according to one embodiment of the present invention includes: a tread section extending in a circumferential direction and having a ring shape; and a pair of sidewall sections arranged on both sides of the tread section. In the tire, one surface of the tread section is provided with a pair of main grooves extending along the circumferential direction on both sides of a tire equator; a shoulder area located on an outer side in a width direction of a main groove is provided with a plurality of shoulder lug grooves extending from the main grooves to the outer side in the width direction and arranged at intervals in the circumferential direction; and with a plurality of shoulder blocks.which are defined by the main groove and the shoulder lug grooves and arranged along the tire's circumferential direction, a sidewall area adjacent to the shoulder area on the outside in the tire's width direction is provided with a plurality of sidewall blocks projecting from an outer surface of each of the sidewall sections, a sidewall groove connected to a shoulder lug groove of the shoulder lug grooves and extending along a tire's radial direction is provided between the sidewall blocks adjacent in the tire's circumferential direction, one of the sidewall blocks is located at a position on an outside in the tire's width direction of a block group consisting of two or more shoulder blocks adjacent in the tire's circumferential direction, a sidewall of each of the shoulder blocks is provided with a curved recessed section that is more deeply recessed than other sections of the sidewall surface,The curved recessed section consists of a first recessed section and a second recessed section extending along the tire's circumferential direction, and a third recessed section connecting the first and second recessed sections and extending obliquely to the tire's circumferential direction. One surface of each of the side blocks is provided with a curved protruding section that protrudes more than other sections of the surface, and the curved protruding section consists of a first protruding section and a second protruding section extending along the tire's circumferential direction, and a third protruding section connecting the first and second protruding sections and extending obliquely to the tire's circumferential direction. Advantageous effects of the invention

[0005] In the tire according to one embodiment of the present invention, when providing the plurality of sidewall blocks in the sidewall region, one sidewall block is arranged at a position on the outside in the tire width direction of the block group, which consists of two or more shoulder blocks that are adjacent in the tire circumference direction. Therefore, the entirety of the block group and the sidewall block essentially functions as one large block, thereby improving block stability.Furthermore, since each shoulder block is provided with the curved recessed section that includes the first to third sections, and each side block is provided with the curved protruding section that includes the first to third sections, the unevenness shape of an area from the side surface of the shoulder block to the surface of the side block becomes more complex, and thus mud or the like can be effectively trapped on unpaved roads, traction performance can be improved, and excellent driving performance can be achieved on poor roads.In particular, edge effects are achieved in various directions, and traction performance can be effectively improved because the curved recessed section and the curved raised section each include sections extending along the tire's circumference (the first recessed section and the second recessed section, and the first raised section and the second raised section) and sections extending obliquely to the tire's circumference (the third recessed section and the third raised section). Such interaction can provide block resistance and driving performance on poor roads in a highly compatible manner.

[0006] In one embodiment of the present invention, it is preferred that the first recessed section opens towards the shoulder lug groove adjacent to each of the shoulder blocks on one side in the circumferential direction of the tire, and that the second recessed section opens towards the shoulder lug groove adjacent to each of the shoulder blocks on the other side in the circumferential direction of the tire. As a result, both ends of the curved recessed section are in contact with the shoulder lug grooves, and thus mud and the like can be easily displaced in the curved recessed section, which is why an improvement in traction performance is to be expected.

[0007] In one embodiment of the present invention, the first protruding section is preferably connected to the side groove adjacent to each of the side blocks on one side in the circumferential direction of the tire, and the second protruding section is connected to the side groove adjacent to each of the side blocks on the other side in the circumferential direction of the tire. As a result, the curved protruding section extends over the entire width of the side block (the entire area from one end to the other in the circumferential direction), and thus the stiffness of the side block can be increased, which is advantageous for improving traction performance.

[0008] In one embodiment of the present invention, a specification can be applied in which the circumference of one of the first protruding sections and the second protruding section is greater than that of the other. Thus, the first protruding section and the second protruding section have different lengths, which makes the unevenness of the curved protruding section more complex, which is advantageous for improving traction performance.

[0009] In one embodiment of the present invention, the curved recessed section preferably has a depth from the side surface of each of the shoulder blocks in a range of 0.5 mm to 2.0 mm. This is advantageous in order to provide block stability and driving performance on poor roads in a compatible manner.

[0010] In one embodiment of the present invention, the curved, protruding section preferably has a height from the surface of each of the side blocks in a range of 0.5 mm to 15 mm. This is advantageous in order to provide block resistance and driving performance on poor roads in a compatible manner.

[0011] In one embodiment of the present invention, the third recessed section has an angle with respect to the tire's circumferential direction, preferably in the range of 20° to 50°. The third protruding section has an angle with respect to the tire's circumferential direction, preferably in the range of 30° to 60°. Such determination of the angles of the respective sections provides satisfactory shapes for the curved recessed section and the curved protruding section, which is advantageous for increasing traction and improving driving performance on poor roads. It should be noted that the "angle formed by the third recessed section with respect to the tire's circumferential direction" is measured based on an imaginary line passing through the center in the width direction of the third recessed section.It is also assumed that "the angle formed by the third protruding section in relation to the tire's circumferential direction" is measured based on an imaginary line passing through the center in the width direction of the third protruding section.

[0012] In one embodiment of the present invention, the third recessed section and the third protruding section are preferably inclined in the same direction with respect to the tire's circumferential direction, and the difference between their angles of inclination with respect to the tire's circumferential direction is 15° or less. When the third recessed section and the third protruding section are inclined in the same direction in this way, the curved recessed section and the curved protruding section have similar shapes, and the combination of these recessed and protruding sections provides a satisfactory bump profile in the area from the side surface of the shoulder block to the surface of the side block, which is advantageous for increasing traction and improving driving performance on poor roads.

[0013] In one embodiment of the present invention, the second protruding section is preferably positioned on the innermost side of the sidewall in the tire radial direction, the first protruding section is positioned on an outer side in the tire radial direction of the second protruding section, and the surface of the sidewall that is more deeply recessed than the curved protruding section is located in a position surrounded by the first and third protruding sections. This increases the complexity of the sidewall irregularity, which is advantageous for increasing traction and improving driving performance on poor roads.

[0014] The tire according to one embodiment of the present invention is preferably a pneumatic tire, but can also be a non-pneumatic tire. In the case of a pneumatic tire, its interior can be filled with air, an inert gas such as nitrogen, or another gas. Brief description of the drawings Fig. Figure 1 is a meridian cross-sectional view of a tire according to an embodiment of the present invention. Fig. Figure 2 is a perspective view illustrating a shoulder area and a side area of ​​the tire according to the embodiment of the present invention. Fig. Figure 3 is an explanatory view that schematically illustrates a shoulder block (side surface) and a side block (surface) of the embodiment of the present invention. Description of embodiments

[0015] Configurations of embodiments of the present invention are described in detail below with reference to the accompanying drawings.

[0016] In the case of a pneumatic tire like the one in Fig. Figure 1 illustrates a tire of an embodiment of the present invention comprising a tread section 1 that comes into contact with a road surface, a pair of sidewall sections 2 arranged on both sides of the tread section 1, and a pair of bead sections 3, each arranged on an inner side in the tire radial direction of each of the pair of sidewall sections. The reference numeral “CL” in Fig. 1 denotes a tire equator. It should be noted that, although in Fig.Figure 1, which is a meridian cross-sectional view, does not illustrate that the tread section 1, the sidewall section 2, and the bead section 3 each extend in the circumferential direction of the tire and form a ring shape, thus creating a basic annular structure of the pneumatic tire. Although the following description uses Fig. 1. Essentially based on the illustrated meridian cross-section, all tire components extend in the tire's circumferential direction and form a ring shape.

[0017] A carcass layer 4 is arranged between a pair of left and right bead sections 3. The carcass layer 4 encloses a plurality of reinforcing cord threads extending in the tire radial direction and is folded back from an inside to an outside around a bead core 5 arranged in each of the bead sections 3. In addition, a bead filler 6 is arranged on one circumference of the bead core 5, and the bead filler 6 is enclosed by a body section and a folded-back section of the carcass layer 4. On the other hand, in the tread section 1, a plurality of belt layers 7 (two layers in Fig.1) embedded on an outer circumferential side of the carcass layer 4. Each of these belt layers 7 encloses a plurality of reinforcing cord threads inclined with respect to the tire's circumferential direction and arranged such that the reinforcing cord threads intersect each other between the layers. In these belt layers 7, the angle of inclination of the reinforcing cord threads with respect to the tire's circumferential direction is specified in a range of, for example, 10° to 40°. Furthermore, at least one belt reinforcement layer 8 (in Fig. 1 two). The belt reinforcement layer 8 includes organic fiber cord threads oriented in the tire's circumferential direction. In the belt reinforcement layer 8, the angle of the organic fiber cord threads with respect to the tire's circumferential direction is, for example, set between 0° and 5°.

[0018] One embodiment of the present invention relates to a shoulder region and a sidewall region of a tire, as described below, and the basic structure (cross-sectional structure) of the tire is not limited to the general structure described above. Furthermore, the detailed shape (tread pattern) of the grooves and blocks formed on the surface of tread section 1 is not subject to any particular restrictions, with the exception of the shoulder region described below. The tread pattern of a section, with the exception of the shoulder region described below, is expediently a pattern that mainly includes blocks suitable for unpaved roads.One embodiment of the present invention can be applied to various tires, including tires without air filling, as long as the tires have areas (sections corresponding to the shoulder area and the side area) that can come into contact with mud and the like on a road surface when driving on unpaved roads.

[0019] As in Fig. 1 and Fig.As illustrated in Figure 2, a surface of the tread section 1 is provided with a pair of main grooves 10 extending along the tire's circumferential direction on both sides of the tire equator CL. The main groove 10 preferably has a zigzag shape, with a linear section inclined in one direction relative to the tire's circumferential direction and a linear section inclined in the other direction being arranged alternately along the tire's circumferential direction. A region between the pair of main grooves 10 is a central region (a region in which any tread pattern can be used without particularly restricting the structure in one embodiment of the present invention), and a region on an outer side in the tire width direction of each main groove 10 is a shoulder region.The main groove 10 has a groove width in a range of preferably 3 mm to 13 mm, more preferably 5 mm to 11 mm and a groove depth in a range of preferably 8 mm to 16 mm, more preferably 10 mm to 15 mm.

[0020] A rib section (shoulder rib section), defined on the outside in the tire width direction of the main groove 10, is provided with a shoulder lug groove 11 extending from the main groove 10 towards the outside in the tire width direction. A plurality of the shoulder lug grooves 11 are preferably arranged at intervals in the tire circumference direction. The shoulder rib section is subdivided into a plurality of blocks (shoulder blocks 12) by the shoulder lug grooves 11. If the main grooves 10 have a zigzag shape, the shoulder lug grooves 11 are preferably connected to each bend point on the outside in the tire width direction of the main groove 10. The groove width of the shoulder lug groove 11 is not particularly limited, but is preferably in a range of 70% to 98% and more preferably in a range of 80% to 95% of the groove width of the main groove 10.The groove depth of the shoulder stud groove 11 is not particularly limited, but is preferably in a range of 75% to 100% and more preferably in a range of 80% to 98% of the groove depth of the main groove 10.

[0021] If an area adjacent to the shoulder area on the outside in the tire width direction is defined as a sidewall area, a plurality of sidewall blocks 13 are provided in this sidewall area, projecting from an outer surface of the sidewall section 2. The protruding height of each sidewall block 13 from the sidewall surface is not limited, but can be specified, for example, to 1 mm to 10 mm. As in Fig. 2 and Fig.As illustrated in Figure 3, each side block 13 is located at a position on the outside in the tire width direction of a block group consisting of two or more shoulder blocks 12 that are adjacent in the tire circumference direction. For example, in the illustrated example, a side block 13 is located at a position on the outside in the tire width direction of a block group consisting of two shoulder blocks 12. In other words, a side groove 14 extending along the tire width direction (tire radial direction) is formed between the side blocks 13 that are adjacent in the tire circumference direction, and the side groove 14 is connected to at least every second of the plurality of shoulder lug grooves 11 that are spaced apart in the tire circumference direction.A side block 13 and two or more shoulder blocks 12 (and one or more shoulder stud grooves 11 not connected to the side groove 14) are arranged between the shoulder stud grooves 11 and side grooves 14 connected in this way.

[0022] The sidewall block 13 is preferably positioned in a suitable area in the tire's radial direction to ensure adequate contact with the road surface when the tire sinks into mud or similar materials while driving on unpaved roads. In particular, the innermost end of the sidewall block 13 is preferably located within a range of 20% to 50% of the tire's cross-sectional height SH from the position of the tire's equator CL towards the inside of the tire's radial direction. In other words, a distance D from the position of the tire's equator CL to the innermost end of the sidewall block 13 in the tire's radial direction is preferably 20% to 50% of the tire's cross-sectional height SH. By positioning the sidewall block 13 in a suitable area in the tire's radial direction of the sidewall section 2, the tire's mileage on unpaved roads can be effectively improved.Furthermore, the size of the sidewall block 13 can be appropriately ensured, which is advantageous for ensuring block stiffness and improving durability. If the distance D is less than 20% of the tire's cross-sectional height SH, the sidewall block 13 will be small. This makes it difficult to maintain satisfactory block stability. If the distance D is more than 50% of the tire's cross-sectional height SH, the sidewall block 13 will be too large, which may impair normal mileage. It should be noted that, relative to the arrangement of the sidewall block 13, the boundary between the shoulder area and the sidewall area, regardless of the presence of a ridge 17, is preferably located within the range of 20% to 25% of the tire's cross-sectional height SH from the position of the tire equator CL towards the inside in the tire radial direction.

[0023] In the combination of two or more shoulder blocks 12 and one side block 13 described above, a side surface of each of the shoulder blocks 12 (a surface of the shoulder block 12 when the tire is viewed from the side) is provided with a curved recessed section 20 that is more deeply recessed than other sections of the side surface of the shoulder block 12. The curved recessed section 20 includes a first recessed section 21 and a second recessed section 22, each extending along the tire's circumferential direction, and a third recessed section 23 that connects the first recessed section 21 and the second recessed section 22 and extends obliquely to the tire's circumferential direction.Likewise, one surface of each of the sideblocks 13 (one surface of the sideblock 13 when the tire is viewed from the side) is provided with a curved protruding section 30 that protrudes more than other sections of the surface of the sideblock 13. The curved protruding section 30 includes a first protruding section 31 and a second protruding section 32, each extending along the tire's circumferential direction, and a third protruding section 33 that connects the first protruding section 31 and the second protruding section 32 and extends obliquely to the tire's circumferential direction.

[0024] In the tire according to one embodiment of the present invention, the entirety of the shoulder blocks 12 (block group) described above and the side block 13 essentially functions as one large block, and the stiffness as a single large block can be ensured. This can improve block resistance.On the other hand, since each shoulder block is provided with the curved recessed section 20, which includes the first recessed section 21, the second recessed section 22 and the third recessed section 23, and each side block is provided with the curved protruding section 30, which includes the first protruding section 31, the second protruding section 32 and the third protruding section 33, the unevenness shape of an area from the side surface of the shoulder block 12 to the surface of the side block 13 becomes more complex, and thus mud or the like can be effectively trapped on unpaved roads, traction performance can be improved, and excellent driving performance can be achieved on poor roads.In particular, since the curved recessed section 20 and the curved protruding section 30 each include sections extending along the tire's circumference (the first recessed section 21 and the second recessed section 22, and the first protruding section 31 and the second protruding section 32), and sections extending obliquely to the tire's circumference (the third recessed section 23 and the third protruding section 33), edge effects are achieved in various directions, and traction performance can be effectively improved. Such interaction can provide block resistance and driving performance on poor roads in a highly compatible manner.

[0025] It should be noted that in the illustrated example, a burr 15, projecting from the sidewall surface and extending around the entire circumference of the tire, is present at a boundary between the sidewall surface on the outside in the tire width direction of the shoulder block 12 and the surface of the sideblock 13 (a boundary between the shoulder region and the sidewall region). The burr 15 is an element formed due to a gap position of a mold or the like and is therefore not necessarily present. The burr 15 is an element that need not be considered in the present invention, but it is an element that is formed during manufacturing, and thus the shoulder region and the sidewall region can be defined with reference to the burr 15.This means that the shoulder area can be considered as an area adjacent to the ridge 15 on the inside in the tire width direction, and the side area can be considered as an area adjacent to the ridge 15 on the inside in the tire radial direction.

[0026] It should be noted that, as described above, the curved recessed section 20 is a section recessed from the side surface of the shoulder block 12, and the curved protruding section 30 is a section projecting from the surface of the side block 13. Therefore, the curved protruding section 30 need not project with respect to the side surface of the shoulder block 12. For example, in the illustrated example, the side surface of the shoulder block 12 and the upper surface of the curved protruding section 30 are in a vertical relationship such that they are connected by the ridge 15 arranged between them, but even in this configuration, the curved recessed section 20 is recessed from the side surface of the shoulder block 12, and the curved protruding section 30 projects from the surface of the side block 13, thereby achieving the uneven shape intended by the present invention.

[0027] When combining two or more adjacent shoulder blocks 12 in the direction of tire width with one side block 13, the ratio between the number of side blocks 13 and the number of shoulder blocks 12 is preferably such that the number of shoulder blocks 12 is two with respect to each side block 13. As a result, the balance in the number of blocks in the combination of side blocks 13 and shoulder blocks 12 is improved, which is advantageous for providing both block resistance and driving performance on poor roads in a compatible manner.

[0028] The depth of the curved recessed section 20 from the side surface of the shoulder block 12 is preferably in the range of 0.5 mm to 2.0 mm, and more preferably from 0.5 mm to 1.5 mm. This is advantageous to provide block stability and driving performance on poor roads in a compatible manner. If the depth of the curved recessed section 20 relative to the side surface of the shoulder block 12 is less than 0.5 mm, the curved recessed section 20 is not sufficiently recessed, and the curved recessed section 20 does not form sufficient unevenness, so a sufficient effect of improving traction performance cannot be expected.If the depth of the curved recessed section 20 in relation to the side surface of the shoulder block 12 exceeds 2.0 mm, the curved recessed section 20 is too deep, and thus the stiffness of the shoulder block 12 is reduced, making it difficult to maintain sufficient block stability.

[0029] The height of the curved, protruding section 30 from the surface of the side block is preferably in the range of 0.5 mm to 15 mm, and more preferably from 1 mm to 3 mm. This is advantageous to provide block resistance and driving performance on poor roads in a compatible manner. If the height of the curved, protruding section 30 relative to the surface of the side block 13 is less than 0.5 mm, the curved, protruding section 30 does not protrude sufficiently, and the curved, protruding section 30 does not form a sufficient unevenness, so that a sufficient effect of improving traction performance cannot be expected.If the height of the curved protruding section 30 exceeds 13 15 mm in relation to the surface of the side block, the curved protruding section 30 will protrude extremely in relation to the circumference, and thus the curved protruding section 30 itself will likely be damaged, making it difficult to maintain the block's stability.

[0030] The specific shape of the curved recessed section 20 is not particularly restricted, as long as the curved recessed section 20 has a curved shape formed by the three sections described above (the first recessed section 21, the second recessed section 22, and the third recessed section 23). However, it is preferred that the first recessed section 21, as in the illustrated example, is positioned on the outside in the tire radial direction relative to the second recessed section 22. In particular, in the illustrated example, the shape is such that the first recessed section 21, which is arranged on one side in the tire circumferential direction (right side in the drawing), is positioned on the outside in the tire radial direction relative to the second recessed section 22, which is arranged on the other side in the tire circumferential direction (left side in the drawing).Furthermore, in the illustrated example, the second recessed section 22 is positioned on the innermost side of the side surface of the shoulder block 12 in the tire radial direction and extends such that it is in contact with the ridge 17 described above. In one embodiment of the present invention, it is preferred that the curved recessed section 20, which has the shape described above, is provided in each of two or more shoulder blocks 12 that are adjacent in the tire circumferential direction, and that the curved recessed sections 20 of the respective shoulder blocks 12 have similar shapes.By providing the curved recessed sections 20 in this way, the unevenness, which has a directional dependence based on the curved recessed sections 20, is repeatedly arranged in the tire circumferential direction, which is advantageous to effectively trap mud and the like and to improve driving performance on poor roads.

[0031] Likewise, the specific shape of the curved protruding section 30 is not particularly restricted, as long as the curved protruding section 30 has a curved shape formed by the three sections described above (the first protruding section 31, the second protruding section 32, and the third protruding section 33). However, it is preferred that the first protruding section 31, as in the illustrated example, is positioned on the outside in the tire radial direction with respect to the second protruding section 32. In particular, the shape, as in the illustrated example, is preferably such that the first protruding section 31, which is arranged on one side in the tire circumferential direction (right side in the drawing), is positioned on the outside in the tire radial direction (left side in the drawing) with respect to the second protruding section 32.That is, the curved protruding section 30 preferably has a curved shape similar to that of the curved recessed section 20, except that the unevenness is reversed compared to that of the curved recessed section 20 and the length is changed in the circumferential direction of the tire.

[0032] By fulfilling the arrangement of the first recessed section 21 and the second recessed section 22 and the arrangement of the first protruding section 31 and the second protruding section 32 described above, the third recessed section 23 and the third protruding section 33 are inclined in the same direction with respect to the tire circumferential direction, and a difference between their angles of inclination with respect to the tire circumferential direction (a difference between an angle α and an angle β described below) is preferably 15° or less and more preferably 10° or less.As a result, the curved protruding section 30 and the curved recessed section 20 have curved shapes that are more similar to each other, and thus the curved recessed section 20 and the curved protruding section 30 formed in the shoulder block 12 and the side block 13 as a whole have a bump which has a directional dependence, which is advantageous to effectively trap mud and the like and to improve driving performance on poor roads.

[0033] In the case where the third recessed section 23 and the third protruding section 33 are inclined in the same direction with respect to the tire's circumferential direction, as described above, an angle α formed by the third recessed section 23 with respect to the tire's circumferential direction is preferably in a range of 20° to 50° and more preferably in a range of 30° to 40°. An angle β formed by the third protruding section 33 with respect to the tire's circumferential direction is preferably in a range of 30° to 60° and more preferably in a range of 40° to 50°. Setting the angles of the respective sections in this way provides satisfactory shapes for the curved recessed section 20 and the curved protruding section 30, which is advantageous for increasing traction and improving driving performance on poor roads.If the angle α is less than 20°, the curved recessed section 20 is not sufficiently curved, and the effect of improving traction performance is limited. If the angle α exceeds 50°, cut resistance may be impaired. If the angle β is less than 30°, the curved protruding section 30 is not sufficiently curved, and the effect of improving traction performance is limited. If the angle β exceeds 60°, cut resistance may be impaired.

[0034] Preferably, the first recessed section 21 opens towards the shoulder lug groove 11, which adjoins the shoulder block 12 on one side in the circumferential direction of the tire, and the second recessed section 22 opens towards the shoulder lug groove 11, which adjoins the shoulder block 12 on the other side in the circumferential direction of the tire. As a result, both ends of the curved recessed section 20 are in contact with the shoulder lug grooves 11, and thus mud and the like can be easily displaced in the curved recessed section, resulting in improved traction performance.

[0035] Preferably, the first projecting section 31 is connected to the side groove 14 adjacent to the side block 13 on one side in the circumferential direction of the tire, and the second projecting section 32 is connected to the side groove 14 adjacent to the side block 13 on the other side in the circumferential direction of the tire. As a result, the curved projecting section 30 extends over the entire width of the side block 13 (the entire area from one end to the other in the circumferential direction), and thus the stiffness of the side block 13 can be increased, which is advantageous for improving traction performance.

[0036] The first protruding section 31 and the second protruding section 32 can have the same circumferential length, but a specification can be applied in which the circumferential length of one of the first protruding section 31 and the second protruding section 32 is greater than that of the other. In the illustrated example, the second protruding section 32, which is located on the outside in the tire radial direction, has a greater circumferential length than the first protruding section 31, which is located on the inside in the tire radial direction. More precisely, in the illustrated example, the first protruding section 31 and the third protruding section 33 are provided in an area corresponding to a shoulder block 12, and the second protruding section 32 is provided in an area corresponding to a shoulder block 12 and the shoulder lug groove 11.Consequently, a size relationship (the second protruding section is larger than the first protruding section) arises between the circumferential lengths of the first protruding section 31 and the second protruding section 32. Since the curved protruding section 30 is formed in this way, the unevenness of the curved protruding section 30 becomes more complex, which is advantageous for improving traction performance.

[0037] In the illustrated example, the second protruding section 32 is located on the inside of the first protruding section 31 in the tire radial direction, and in particular on the innermost side of the side block 13 in the tire radial direction. On the other hand, a surface of the side block 13 (designated by reference numeral 13a in the drawing), which is more deeply recessed than the curved protruding section 30, is located in a position surrounded by the first protruding section 31 and the third protruding section 33. That is, the surface of the side block 13 (the surface that is more deeply recessed than the curved protruding section 30) can be located on either the inside or the outside of the curved protruding section 30 in the tire radial direction.This makes the irregularity of side block 13 more complex, which is beneficial for increasing traction performance and improving driving performance on poor roads.

[0038] Since one embodiment of the present invention relates mainly to the curved recessed section 20 and the curved protruding section 30, other structures are not particularly limited, but as in the illustrated example, a lateral recessed section 34, recessed with respect to the surface of the side block 13, can be provided on an extension line of the shoulder lug groove 11, which is positioned between the block groups, each enclosing two shoulder blocks 12. The lateral recessed section 34 terminates within the side block 13, so that it is interrupted by the curved protruding section 30. Providing the lateral recessed section 34 increases the complexity of the surface irregularity of the side block 13, which is advantageous for increasing traction and improving driving performance on poor roads.

[0039] The present invention is further described below with reference to examples, but the scope of the present invention is not limited to these examples. Examples

[0040] Eighteen types of pneumatic tires of example 1 of the prior art, comparative examples 1 to 3 and examples 1 to 14 were manufactured, each having a tire size of LT265 / 70R17 121 / 118S, which in Fig. 1 illustrated basic structure (cross-sectional structure) which was based on Fig.2 based structure of the shoulder area and the sidewall area and the number of shoulder blocks adjacent to a sidewall block on the outside in the tire radial direction, the presence or absence of the curved recessed section, the angle α of the third recessed section with respect to the tire circumferential direction, the end section shape of the first recessed section, the end section shape of the second recessed section, the presence or absence of the curved protruding section, the angle β of the third protruding section with respect to the tire circumferential direction, the end section shape of the first protruding section, the end section shape of the second protruding section, the angle difference |β| - |α| between the angle α of the third recessed section with respect to the tire circumferential direction and the angle β of the third protruding section with respect to the tire circumferential direction,the depth of the curved recessed section, the depth of the curved protruding section, and the presence or absence of the side block surface on the inside in the tire radial direction of the curved protruding section, as shown in Tables 1 and 2.

[0041] It should be noted that the tread pattern of the center area is common to all examples and features a structure in which a row of blocks is arranged between a pair of main grooves and on both sides of the tire equator.

[0042] In the column “Angle α of the third recessed section with respect to the tire circumference direction” in Tables 1 and 2, if the number of shoulder blocks adjacent to a side block on the outside in the tire radial direction is “2”, and each shoulder block has a curved recessed section, then each curved recessed section encloses a third recessed section, thus representing the value of each angle α. Note that the fact that the angle α in Example 13 is a negative value means that its inclination direction is opposite to that of the other angles α. Similarly, in Example 14, where the angle β of the third protruding section with respect to the tire circumference direction is a negative value, the inclination direction of the third recessed section and the inclination direction of the third protruding section are opposite to each other.

[0043] The columns "End shape of the first recessed section" and "End shape of the second recessed section" in Tables 1 and 2 indicate whether an end of the first recessed section or the second recessed section is connected to the shoulder stud groove. The case where one end opens towards the shoulder stud groove is indicated as "open," and the case where one end terminates within the shoulder block is indicated as "terminating." The columns "End shape of the first protruding section" and "End shape of the second protruding section" in Tables 1 and 2 indicate whether an end of the first protruding section or the second protruding section is connected to the side groove. The case where one end is connected to the side groove is indicated as "connected," and the case where one end terminates within the side block is indicated as "terminating."

[0044] The pneumatic tires were evaluated for their driving performance on poor roads and block resistance using the evaluation procedures described below, the results of which are given together in Tables 1 and 2. Driving performance on bad roads

[0045] Each test tire was mounted on a wheel with a rim size of 17 × 8 J and fitted to a test vehicle (traction test car) with a front tire pressure of 450 kPa and a rear tire pressure of 550 kPa. A test driver then performed a sensory evaluation of traction characteristics (starting behavior) on a test track consisting of an unpaved road (gravel surface). Evaluation results are expressed as index values, with Example 1 of the prior art assigned an index value of 100. Higher index values ​​indicate excellent performance on snow. Block resistance (cut resistance)

[0046] Each test tire was mounted on a wheel with a rim size of 17 × 8J, inflated to a pressure of 350 kPa, and fitted to a test vehicle (all-wheel-drive SUV). The total cut length was measured after driving a distance of 1,000 km on an off-road durability evaluation track. The evaluation results are expressed as index values, with 100 assigned to the inverse of the measurement value of Example 1 of the prior art. A higher index value indicates a shorter total cut length and excellent block resistance (cut resistance). Table 1-I State of the art example 1 Comparative example 1 Example 1 Comparative example 2 Comparative example 3 Number of shoulder blocks adjacent to the side block 1 2 2 2 2 Presence of the curved recessed section No No Yes Yes No Angle α of the third recessed section (°) - 37 37 - - 37 37 - End section form of the first recessed section - - Open Open - End section shape of the second recessed section - - Open Open - Presence of the curved recessed section No No Yes No Yes Angle β of the third protruding section (°) - - 45 - 45 End section shape of the first protruding section - - Tied together - Tied together End section form of the second protruding section - - Tied together - Tied together Angle difference |β| - |α| (°) - - 8 - - Depth of curved recessed section (mm) - - 1 1 - Height of the curved protruding section (mm) - - 2 - 2 Presence of an upper sidewall surface on the inside in the tire radial direction of the curved protruding section - - Yes - Yes Driving performance on poor roads (index value) 100 100 110 103 103 Block resistance (index value) 100 110 107 108 108 Table 1-II Example 2 Example 3 Example 4 Example 5 Number of shoulder blocks adjacent to the side block 2 2 2 2 Presence of the curved recessed section Yes Yes Yes Yes Angle α of the third recessed section (°) 37 37 37 37 37 37 37 37 End section form of the first recessed section Ending Open Ending Open End section shape of the second recessed section Ending Open Ending Open Presence of the curved recessed section Yes Yes Yes Yes Angle β of the third protruding section (°) 45 45 45 45 End section shape of the first protruding section Ending Ending Tied together Tied together End section form of the second protruding section Ending Ending Tied together Tied together Angle difference |β| - |α| (°) 8 8 8 8 Depth of curved recessed section (mm) 1 1 1 1 Height of the curved protruding section (mm) 2 2 2 2 Presence of an upper sidewall surface on the inside in the tire radial direction of the curved protruding section Yes Yes Yes No Driving performance on poor roads (index value) 108 109 109 108 Block resistance (index value) 107 107 107 106 Table 2-I Example 6 Example 7 Example 8 Example 9 Example 10 Number of shoulder blocks adjacent to the side block 2 2 2 2 2 Presence of the curved recessed section Yes Yes Yes Yes Yes Angle α of the third recessed section (°) 20 50 90 37 37 20 50 90 37 37 End section form of the first recessed section Open Open Open Open Open End section form of the second recessed section Open Open Open Open Open Presence of the curved recessed section Yes Yes Yes Yes Yes Angle β of the third protruding section (°) 30 60 90 45 45 End section shape of the first protruding section Tied together Tied together Tied together Tied together Tied together End section form of the second protruding section Tied together Tied together Tied together Tied together Tied together Angle difference |β| - |α| (°) 10 10 0 8 8 Depth of curved recessed section (mm) 1 1 1 0,5 2 Height of the curved protruding section (mm) 2 2 2 2 2 Presence of an upper sidewall surface on the inside in the tire radial direction of the curved protruding section Yes Yes Yes Yes Yes Driving performance on poor roads (index value) 106 106 105 106 110 Block resistance (index value) 107 107 107 107 105 Table 2-II Example 11 Example 12 Example 13 Example 14 Number of shoulder blocks adjacent to the side block 2 2 2 2 Presence of the curved recessed section Yes Yes Yes Yes Angle α of the third recessed section (°) 37 37 37 37 37 37 -37 37 End section form of the first recessed section Open Open Open Open End section form of the second recessed section Open Open Open Open Presence of the curved recessed section Yes Yes Yes Yes Angle β of the third protruding section (°) 45 45 45 -45 End section shape of the first protruding section Tied together Tied together Tied together Tied together End section form of the second protruding section Tied together Tied together Tied together Tied together Angle difference |β| - |α| (°) 8 8 8 8 Depth of curved recessed section (mm) 1 1 1 1 Height of the curved protruding section (mm) 0,5 15 2 2 Presence of an upper sideblock surface on the inside in the tire radial direction of the bent protruding section Yes Yes Yes Yes Driving performance on poor roads (index value) 106 110 109 109 Block resistance (index value) 107 105 105 105

[0047] As can be seen from Tables 1 and 2, the pneumatic tires of Examples 1 to 14, compared to those of Prior Art Example 1, provide improved road performance on poor roads and block resistance in a well-balanced and compatible manner. On the other hand, since the structure of Comparative Example 1 is such that two shoulder blocks adjoin one side block, block resistance was improved compared to Prior Art Example 1, but the effect of improved road performance on poor roads was not achieved because the curved recessed section and the curved protruding section were not provided. In Comparative Example 2, the curved recessed section was provided, but the curved protruding section was not, and thus the effect of a sufficient improvement in road performance on poor roads was not achieved.In comparison example 3, the curved protruding section was provided, but the curved recessed section was not provided, and thus the effect of sufficiently improving driving performance on poor roads was not achieved. List of reference symbols 1 tread section 2 Side wall section 3 bead section 4 Carcass layer 5 bead core 6 bead fillers 7th belt layer 8 Belt reinforcement layer 10 Main groove 11 Shoulder stud groove 12 Shoulder block 13 page block 14 side groove 15 degrees 20 curved recessed section 21 first in-depth section 22 second in-depth section 23 third in-depth section 30 curved protruding section 31 first prominent section 32 second prominent section 33 third prominent section 34 lateral recessed section CL tire equator 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 2017-124733 A

[0002] JP 2020-044882 A

[0002]

Claims

[1] Tires, including: a tread section that extends in a circumferential direction of the tire and has a ring shape; and a pair of sidewall sections arranged on both sides of the tread section; a surface of the tread section which is provided with a pair of main grooves extending along the tire's circumferential direction on both sides of a tire equator, wherein a shoulder area located on an outer side in a tire width direction of a main groove of the main grooves is provided with a plurality of shoulder lug grooves extending from the main groove towards the outer sides in the tire width direction and arranged at intervals in the tire circumference direction, and with a plurality of shoulder blocks defined by the main groove and the shoulder lug grooves and arranged along the tire circumference direction, wherein a sidewall area adjacent to the shoulder area on the outside in the tire width direction is provided with a plurality of sidewall blocks projecting from an outer surface of each of the sidewall sections and a sidewall groove connected to a shoulder lug groove of the shoulder lug grooves and extending along a tire radial direction provided between the sidewall blocks adjacent in the tire circumferential direction, wherein one of the side blocks is arranged at a position on an outside in the tire width direction of a block group consisting of two or more of the shoulder blocks that are adjacent in the tire circumferential direction, wherein a side surface of each of the shoulder blocks is provided with a curved recessed section which is more deeply recessed than other sections of the side surface, wherein the curved recessed section consists of a first recessed section and a second recessed section extending along the tire circumference direction, and a third recessed section connecting the first recessed section and the second recessed section and extending obliquely to the tire circumference direction, wherein a surface of each of the side blocks is provided with a curved protruding section that protrudes more than other sections of the surface, and the curved protruding section consists of a first protruding section and a second protruding section extending along the tire's circumferential direction, and a third protruding section connecting the first protruding section and the second protruding section and extending obliquely to the tire's circumferential direction. [2] Tires according to claim 1, wherein the first recessed section opens towards the shoulder lug groove adjacent to each of the shoulder blocks on one side in the tire's circumferential direction, and the second recessed section opens towards the shoulder lug groove adjacent to each of the shoulder blocks on the opposite side in the tire's circumferential direction. [3] Tires according to claim 1 or 2, wherein the first protruding section is connected to the side groove that borders each of the side blocks on one side in the tire's circumferential direction, and the second protruding section is connected to the side groove that borders each of the side blocks on the opposite side in the tire's circumferential direction. [4] Tires according to any one of claims 1 to 3, wherein one of the first protruding section and the second protruding section has a tire circumference length that is greater than that of the other. [5] Tires according to any one of claims 1 to 4, wherein the curved recessed section has a depth from the side surface of each of the shoulder blocks in a range of 0.5 mm to 2.0 mm. [6] Tires according to any one of claims 1 to 5, wherein the curved protruding section has a height from the surface of each of the side blocks in a range of 0.5 mm to 15 mm. [7] Tires according to any one of claims 1 to 6, wherein the third recessed section has an angle with respect to the tire circumferential direction in a range of 20° to 50°. [8] Tires according to any one of claims 1 to 7, wherein the third protruding section has an angle with respect to the tire circumferential direction in a range of 30° to 60°. [9] Tires according to any one of claims 1 to 8, wherein the third recessed section and the third protruding section are inclined in the same direction with respect to the tire circumferential direction and a difference in the inclination angles with respect to the tire circumference direction is 15° or less. [10] Tires according to any one of claims 1 to 9, wherein the second protruding section is positioned on the innermost side in the tire radial direction of each of the side blocks, the first protruding section is positioned on an outer side in the tire radial direction of the second protruding section and the surface of each of the side blocks, which is more deeply recessed than the curved protruding section, is located in a position surrounded by the first protruding section and the third protruding section.

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