tire

Abstract

A tire is provided that improves braking performance on ice and driving performance on snow. The tire tread has multiple circumferential main grooves, multiple lateral grooves extending in directions intersecting the circumferential main grooves, and multiple land portions divided by the circumferential main grooves and arranged in directions intersecting the circumferential main grooves. A specific land portion, having at least one land portion, includes: multiple sipes extending at the contact surface in directions intersecting the circumferential main grooves; and multiple grooves extending in directions intersecting the circumferential main grooves with a depth of 1.50 mm or less. In the central region of the tire width direction, when moving from one side of the width direction to the other, the sipes and grooves move in different directions in the tire circumferential direction. In the edge regions on both sides, further outward in the tire width direction than the central region, when moving from one side of the width direction to the other, the sipes and grooves move in the same direction in the tire circumferential direction. A specific land portion includes land portions having one or more land portions on the outer side of the tire width direction.

Description

Technical Field

[0001] This invention relates to tires, and more specifically, to tires having a plurality of sipes on the tread surface. Background Technology

[0002] In recent years, studless tires have been required to balance braking performance on ice and driving performance on snow. To improve braking performance on ice, these studless tires employ multiple sipes on the tread surface on the land side, with the sipes within the same block arranged separately (split) along the tire width. This ensures block rigidity and prevents snow or ice from clogging the sipes.

[0003] On the other hand, the above configuration has the following problem: at the part where the sipe pattern is separated in the tire width direction orthogonal to the tire circumference, the ground pressure locally increases, and the load durability deteriorates. Therefore, conventionally, a configuration has been proposed in which a circumferential groove extending along the tire circumference is provided at the part where the sipe pattern is separated in the tire width direction (see, for example, Patent Document 1).

[0004] Existing technical documents

[0005] Patent documents

[0006] Patent Document 1: Japanese Patent Application Publication No. 2018-34524 Summary of the Invention

[0007] The problem that the invention aims to solve

[0008] In tires where the sipes within the same piece are arranged separately along the tire width, there is room for further improvement in braking performance on ice and driving performance on snow.

[0009] The present invention was made in view of the above circumstances, and its object is to provide a tire that can improve braking performance on ice and driving performance on snow.

[0010] Methods for solving problems

[0011] To address the aforementioned issues and achieve the objective, the tire of the present invention has a tread portion comprising a plurality of circumferential main grooves extending in the tire circumferential direction, a plurality of lateral grooves extending in a direction intersecting the circumferential main grooves, and a plurality of land portions divided by the circumferential main grooves and arranged in a direction intersecting the circumferential main grooves. A specific land portion, comprising at least one of the land portions, includes: a plurality of sipes extending at the contact surface in a direction intersecting the circumferential main grooves; and a plurality of grooves extending in a direction intersecting the circumferential main grooves and having a groove depth of 1.50 mm or less. In the central region of the tire width direction, when moving from one side of the width direction to the other, the sipes and the grooves move in different directions in the tire circumferential direction. In the edge regions on both sides, further outward in the tire width direction than the central region, when moving from one side of the width direction to the other, the sipes and the grooves move in the same direction in the tire circumferential direction. The specific land portion includes land portions having one or more land portions on the outer side of the tire width direction.

[0012] Preferably, the specific land area is a plurality of blocks divided by the circumferential main groove and the transverse groove.

[0013] Preferably, for the specific land portion, when the length in the direction intersecting the circumferential main channel is set to 100%, the length in the direction intersecting the circumferential main channel of the central region is more than 60% and less than 80%.

[0014] Preferably, the inclination angle of the sipe pattern relative to the tire circumference is more than 45° and less than 80°.

[0015] Preferably, the inclination angle of the central region of the groove relative to the tire circumference is more than 40° and less than 65°.

[0016] Preferably, the inclination angle of the edge region of the groove relative to the tire circumference is more than 50° and less than 80°.

[0017] Preferably, for the fine groove, the groove depth is 0.05 mm or more and 1.50 mm or less, the groove width is 0.10 mm or more and 0.80 mm or less, and the distance between adjacent fine grooves is 0.50 mm or more and 2.00 mm or less.

[0018] Preferably, for the groove, the end of the central region is connected to the end of the edge region.

[0019] Invention Effects

[0020] The tire of this invention can improve braking performance on ice and driving performance on snow. Attached Figure Description

[0021] Figure 1 This is a plan view showing the tread surface of the pneumatic tire according to this embodiment.

[0022] Figure 2 This is an enlarged view showing one of the shoulder land portions of the tread surface of the pneumatic tire of this embodiment.

[0023] Figure 3 This is an enlarged view showing one side of the second land portion of the tread surface of the pneumatic tire of this embodiment.

[0024] Figure 4 This is an enlarged view showing the central land portion of one side of the tread surface of the pneumatic tire of this embodiment.

[0025] Figure 5 This is an enlarged view showing the central land portion of the other side of the tread surface of the pneumatic tire of this embodiment.

[0026] Figure 6 This is an enlarged view showing the second land portion of the other side of the tread surface of the pneumatic tire of this embodiment.

[0027] Figure 7 This is an enlarged view showing the shoulder portion of the pneumatic tire of this embodiment, on the other side of the tread surface.

[0028] Figure 8 This is a plan view showing the tread surface of an inflatable tire according to other embodiments. Detailed Implementation

[0029] Hereinafter, embodiments of the present invention will be described in detail with reference to the accompanying drawings. However, the present invention is not limited to these embodiments. Furthermore, the constituent elements of these embodiments include elements that can be substituted and are easily substituted by those skilled in the art, or elements that are substantially the same.

[0030] The pneumatic tire of this embodiment will be described. In the following description, the tire radial direction refers to the direction orthogonal to the tire's axis of rotation, the inner radial direction refers to the side facing the axis of rotation in the tire's radial direction, and the outer radial direction refers to the side leaving the axis of rotation in the tire's radial direction. The tire circumferential direction refers to the direction surrounding the aforementioned axis of rotation. Furthermore, the tire width direction refers to the direction parallel to the aforementioned axis of rotation, the inner tire width direction refers to the side facing the tire equatorial plane (tire equator) in the tire width direction, and the outer tire width direction refers to the side leaving the tire equatorial plane in the tire width direction. Additionally, the tire equatorial plane refers to a plane orthogonal to the axis of rotation of the pneumatic tire and passing through the center of the tire's width.

[0031] Figure 1This is a plan view showing the tread surface of the pneumatic tire according to this embodiment. Figure 1 In the attached figures, CL indicates the equatorial plane of the tire, and T indicates the contact patch of the tire. Furthermore, the pneumatic tire 1 (hereinafter sometimes simply referred to as tire 1) of this embodiment is specified with respect to its mounting direction relative to the vehicle. Figure 1 In the example, the tread pattern becomes asymmetrical, centered on the tire's equatorial plane CL. Furthermore, in... Figure 1 In the region shown on the outer side of the tire width direction, which is closer to the grounding end T, the so-called sidewall portion is included.

[0032] The grounding terminal T is defined as the position of the maximum axial width of the tire at the contact surface between the tire 1 and the flat plate when the tire 1 is mounted on a specified rim, given a specified internal pressure, and placed perpendicularly to the flat plate in a stationary state and subjected to a load corresponding to a specified load.

[0033] The specified rim refers to the "applicable rim" as specified by JATMA, the "Design Rim" as specified by TRA, or the "Measuring Rim" as specified by ETRTO. The specified internal pressure refers to the maximum value of the "maximum air pressure" as specified by JATMA, the "TIRE LOAD LIMITS AT VARIOUS COLDINFLATION PRESSURES" as specified by TRA, or the "INFLATION PRESSURES" as specified by ETRTO. The specified load refers to the maximum value of the "maximum load capacity" as specified by JATMA, the "TIRE LOAD LIMITS AT VARIOUS COLD INFLATION PRESSURES" as specified by TRA, or the "LOADCAPACITY" as specified by ETRTO. However, in the case of passenger car tires, JATMA specifies an internal pressure of 180 kPa and a load of 88% of the maximum load capacity.

[0034] The tread portion 10 of tire 1 is made of rubber material (tread rubber) and is exposed on the outermost side of the radial direction of tire 1, its surface forming the outline of tire 1. The surface of the tread portion 10 is formed into a tread surface 12 that comes into contact with the road surface when the vehicle (not shown) on which tire 1 is mounted is in motion.

[0035] The tire 1 has multiple circumferential main grooves 21, 22, 23, 24, 25 extending along the tire circumference on its tread surface 12; multiple land portions 31, 32, 33, 34, 35, 36 divided by these circumferential main grooves 21, 22, 23, 24, 25; multiple lateral grooves 311, 321, 322, 331, 351, 361 disposed on each land portion 31, 32, 33, 34, 35, 36; multiple sipes 4 disposed on each land portion 31 to 36; and fine grooves 5 disposed on each land portion 31, 32, 33, 34, 35, 36. Here, the circumferential main grooves 21, 22, 23, 24, 25 are grooves extending in the tire circumference and having the display obligation of wear indicators as specified by JATMA, and generally have a groove width of 5.0 mm or more and a groove depth of 6.5 mm or more. Lateral grooves 311, 321, 322, 331, 341, and 351 are lateral grooves extending in the direction intersecting the circumferential main grooves (in the tire width direction), typically having a groove width of 1.0 mm or more and a groove depth of 3.0 mm or more. Additionally, sipes 4 refer to cuts formed on the tread surface 12, typically having a sipe width of less than 1.0 mm and a sipe depth of 2.0 mm or more, thus closing when the tire contacts the ground. Grooves 5 are shallow grooves formed on the tread surface 12. The groove depth of grooves 5 is shallower than the groove depth of sipes 4. For grooves 5, typically, the groove depth is 0.05 mm or more and 1.50 mm or less, the groove width is 0.10 mm or more and 0.80 mm or less, and the distance (spacing) between adjacent grooves 5 is 0.50 mm or more and 2.00 mm or less. Thus, the tire 1 of this embodiment is a studless anti-skid tire with sipes 4 and grooves 5 provided on the tread surface 12. The shapes of the sipes 4 and grooves 5 will be described later.

[0036] On the tread surface 12, multiple (in) extending along the tire circumference Figure 1 Five circumferential main grooves (21, 22, 23, 24, and 25) are arranged at predetermined intervals along the tire width direction. In this embodiment, as... Figure 1 As shown, the circumferential main grooves 21, 22, 23, 24, and 25 are arranged in the order of inner side in the vehicle width direction and outer side in the vehicle width direction. Circumferential main groove 23 is the circumferential main groove closest to the tire equatorial plane CL. In this embodiment, two circumferential main grooves 21 and 22 are respectively located on the inner side in the vehicle width direction, and two circumferential main grooves 24 and 25 are respectively located on the outer side in the vehicle width direction. Here, the inner side and outer side in the vehicle width direction are defined as the orientation relative to the vehicle width direction when the tire 1 is mounted on the vehicle. Furthermore, the two outermost circumferential main grooves 21 and 25 in the tire width direction are defined as shoulder main grooves, and the three circumferential main grooves 22, 23, and 24 on the inner side in the tire width direction are defined as central main grooves.

[0037] exist Figure 1In the example, the circumferential main grooves 21 and 25, which are the main shoulder grooves, are straight lines with a constant width in the circumferential direction. The circumferential main grooves 22 and 24 in the central main groove are formed as serrations that extend along the tire circumference and have amplitude in the tire width direction. The circumferential main groove 23 in the central main groove is a straight line. For the circumferential main groove 22, which is the inner side of the central main groove in the vehicle width direction, the groove wall on the tire equatorial surface CL side is formed as a straight line with a constant position in the tire width direction, while the groove wall on the contact end T side is formed as a serration that extends along the tire circumference and has amplitude in the tire width direction. Furthermore, the number of circumferential main grooves 21, 22, 23, 24, and 25 is not limited to the above number, and there may be 4 or fewer or 6 or more grooves on the tread surface 12.

[0038] Additionally, on the tread surface 12, multiple grooves extending circumferentially along the tire are formed by five circumferential main grooves 21, 22, 23, 24, and 25. Figure 1 The tire has six sections (31, 32, 33, 34, 35, and 36). In this embodiment, sections 31 and 36, which are divided outwards in the tire width direction by the circumferential main grooves 21 and 25, which serve as the main shoulder grooves, are defined as shoulder sections. Section 32, divided by the circumferential main grooves 21 and 22, and section 35, divided by the circumferential main grooves 24 and 25, which are adjacent to shoulder sections 31 and 36 in the tire width direction across the shoulder main grooves, are defined as second sections. Section 33, divided by the circumferential main grooves 22 and 23, and section 34, divided by the circumferential main grooves 23 and 24, which serve as the central main grooves, are defined as central sections. Sections 33 and 34, which are central sections, are located near the tire's equatorial plane CL.

[0039] exist Figure 1 In the example, there are two central land sections, namely land sections 33 and 34, but in a configuration with four circumferential main channels, only one central land section is formed. Furthermore, in a configuration with three circumferential main channels, the central land section can also serve as a second land section.

[0040] The left and right shoulder land portions, namely land portions 31 and 36, each have multiple lateral grooves 311 and 361. For these lateral grooves 311 and 361, one end opens into the circumferential main grooves 21 and 25, which serve as the main shoulder grooves, and extends outward in the tire width direction; the other end terminates in the area crossing the contact patch T. Multiple lateral grooves 311 and 361 are repeatedly arranged along the tire circumference in the land portions 31 and 36. Therefore, the land portions 31 and 36, as shoulder land portions, are divided into multiple blocks (shoulder blocks) by these lateral grooves 311 and 361. These blocks are formed with multiple sipes 4 and multiple grooves 5. Circumferential grooves 312 and 362 extend along the tire circumference, with one end opening into the lateral grooves 311 and 361, and the other end terminating within the block. The ends of the circumferential grooves 312 and 362 on different sides of the tire circumference are open at the transverse groove openings.

[0041] Furthermore, the second land portion 32 on the inner side in the vehicle width direction has two types and multiple transverse grooves 321 and 322. For the transverse groove 321 (first transverse groove), one end faces the other end of the aforementioned transverse groove 311 and opens into the shoulder main groove 21, while the other end terminates inside the second land portion 32. Similarly, for the transverse groove 322 (second transverse groove), one end opens into the central main groove 22, and the other end terminates inside the second land portion 32. Figure 1 In the example, one end of the lateral groove 322 opens at a corner protruding towards the ground end T in the serrated central main groove 22. Therefore, the lateral grooves 321 and 322 have a semi-closed structure that does not traverse the second land portion 32. Furthermore, these lateral grooves 321 and 322 are arranged in an alternating (staggered) configuration in the tire circumferential direction, extending obliquely in the same direction in the tire circumferential direction, and overlapping in the tire width direction. Therefore, the second land portion 32 is formed as a continuous stripe pattern in the tire circumferential direction without being interrupted by the lateral grooves 321 and 322. The second land portion 32 has multiple sipes 4 and multiple fine grooves 5 formed on the stripe pattern.

[0042] The central landmass 33 has multiple transverse grooves 331. Figure 1 Only one lateral groove 331 is shown, but multiple lateral grooves 331 are formed in the circumferential direction of the tire. The lateral groove 331 is formed by extending along the width direction of the tire between two central main grooves, namely the circumferential main grooves 22 and 23, with its two ends opening into the circumferential main grooves 22 and 23, which serve as the central main grooves, respectively. The land section 33, which serves as the central land section, is divided into multiple blocks by the multiple lateral grooves 331, and each block is provided with multiple fine grooves 332 and multiple sipes 4.

[0043] The central landmass 34 has multiple transverse grooves 341. Figure 1Only one lateral groove 341 is shown in the diagram, but multiple lateral grooves 341 are formed in the tire's circumferential direction. The lateral groove 341 extends along the tire's width between two central main grooves, namely the circumferential main grooves 23 and 24, with its two ends opening into the circumferential main grooves 23 and 24, which serve as the central main grooves. Figure 1 In this example, one end of the transverse groove 341 opens at a corner of the circumferential main groove 24, which is a serrated central main groove, and protrudes towards the tire equatorial plane CL, and extends along the extending direction of the shorter portion of the circumferential main groove 24. Furthermore, the transverse groove 341 is provided at every other corner relative to the aforementioned serrated corner of the circumferential main groove 24. The land portion 34, which serves as the central land portion, is divided into multiple blocks by the multiple transverse grooves 341, and each block is provided with multiple sipes 4 and multiple grooves 5.

[0044] The second land portion 35 on the outer side in the vehicle width direction has multiple lateral grooves 351 and circumferential grooves 352. The lateral grooves 351 are formed extending along the tire width direction between adjacent central main grooves 24 and shoulder main grooves 25, with one end opening in the central main groove 24 and the other end opening in the shoulder main groove 25. Figure 1 In this example, one end of the transverse groove 351 opens at a corner protruding towards the ground end T of the serrated central main groove 24, while the other end faces the end of one of the transverse grooves 361 and opens in the shoulder main groove 25. The second land portion 35 is divided into multiple blocks by the multiple transverse grooves 351. In each of these blocks, circumferential grooves 352 are formed. Figure 1 In this example, the circumferential groove 352 is formed as a serrated shape that extends along the tire circumference and has an amplitude in the tire width direction. The circumferential groove 352 is a groove that extends along the tire circumference and has a groove width of 1.0 mm or more and 3.0 mm or less. In addition, a plurality of sipes 4 and a plurality of grooves 5 are formed in the second land portion 35.

[0045] Furthermore, the pneumatic tire 1 of this embodiment has the same meridional cross-sectional shape as conventional pneumatic tires. Here, the meridional cross-sectional shape of a pneumatic tire refers to the cross-sectional shape of the pneumatic tire as presented on a plane perpendicular to the tire's equatorial plane CL. Although the figures are omitted, in a meridional cross-section, the tire 1 of this embodiment has a bead portion, a sidewall portion, a shoulder portion, and a tread portion 10 extending radially from the inner side of the tire to the outer side. Furthermore, the tire 1, for example, in a meridional cross-section, includes a carcass layer extending from the tread portion 10 to both sides and wound around a pair of bead cores, and a belt layer and a belt reinforcement layer sequentially formed on the radially outer side of the carcass layer.

[0046] Next, the knife groove pattern 4 and fine groove 5 formed on the land surface 31, 32, 33, 34, 35, and 36 will be explained. Figure 2This is an enlarged view showing one of the shoulder land portions of the tread surface of the pneumatic tire of this embodiment. Figure 3 This is an enlarged view showing one of the second land portions of the tread surface of the pneumatic tire of this embodiment. Figure 4 This is an enlarged view showing the central land portion of one side of the tread surface of the pneumatic tire of this embodiment. Figure 5 This is an enlarged view showing the central land portion of the other side of the tread surface of the pneumatic tire of this embodiment. Figure 6 This is an enlarged view showing the second land portion of the other side of the tread surface of the pneumatic tire of this embodiment. Figure 7 This is an enlarged view showing the shoulder portion of the pneumatic tire of this embodiment, on the other side of the tread surface.

[0047] Figure 2 The land portion 31 shown has sipes 4 and grooves 5 formed on its tread surface as described above. Figure 2 As shown, multiple sipes 4 extend along the tire width direction and are arranged in a plurality of configurations along the tire circumference. The sipes 4 extend along line segment 102a. Line segment 102a is inclined relative to both the tire circumference and tire width directions. Furthermore, the sipes 4 are formed in a serrated shape, with multiple sipes continuously bending towards the opening of the tread surface 12. Line segment 102a can be, for example, a line connecting the vertices of the serrated shapes on the same side of the tire circumference. The sipes 4 can be two-dimensional sipes extending radially inward from the tread surface 12 into the tire tread portion 10, with the shape following the serrated shape of the tread surface 12, or they can be three-dimensional sipes that are further bent beyond the serrated shape. The angle (inclination angle) between the sipes 4 and the tire circumference is θa.

[0048] The fine groove 5 is a groove whose depth is shallower than that of the groove pattern 4. The shape of the bottom of the fine groove 5 is not limited to a flat bottom; for example, it can also be U-shaped or V-shaped in cross-section. Figure 2 As shown, multiple grooves 5 extend along the tire width direction and are arranged in a plurality of configurations along the tire circumference. The grooves 5 formed in the land portion 31 include grooves 120a, 122a, and 124a. The grooves 120a, 122a, and 124a are formed at different positions in the tire width direction. Groove 120a is formed in the central portion of the land portion 31 in the tire width direction, i.e., the central region 110a. Groove 122a is formed in the edge region 112a of the land portion 31, which is closer to the central region 110a in the vehicle width direction. Groove 124a is formed in the edge region 114a of the land portion 31, which is closer to the central region 110a in the vehicle width direction. The central region 110a and the edge regions 112a and 114a are adjacent regions. The inner end of groove 120a in the vehicle width direction is connected to groove 122a, and the outer end of groove 120a in the vehicle width direction is connected to groove 124a.

[0049] Here, the inclination directions of grooves 120a, 122a, and 124a relative to the tire circumferential and tire width directions are different. That is, when grooves 120a, 122a, and 124a move from the outer side to the inner side in the vehicle width direction, their directions of movement in the tire circumferential direction are different. The angle (inclination angle) between groove 120a and the tire circumferential direction is θ1. The angle (inclination angle) between groove 122a and the tire circumferential direction is θ2. The angle (inclination angle) between groove 124a and the tire circumferential direction is θ3. Inclination angles θ2 and θ3 are the same angle.

[0050] The groove 120a has a different inclination direction relative to the sipe 4 in both the tire circumferential and tire width directions. In other words, when the groove 120a and the sipe 4 move from the outer side to the inner side in the vehicle width direction, their directions of movement in the tire circumferential direction are different. However, when the grooves 122a and 124a, and the sipe 4 move from the outer side to the inner side in the vehicle width direction, their directions of movement in the tire circumferential direction are the same.

[0051] Figure 3 As described above, the land section 32 has sipes 4 and grooves 5 formed on its tread surface. The basic shapes of the sipes 4 and grooves 5 are the same as those of the land section 31. The grooves 5 formed on the land section 32 include grooves 120b, 122b, and 124b. The grooves 120b, 122b, and 124b are formed in different positions in the tire width direction. Groove 120b is formed in the central portion of the land section 32 in the tire width direction, i.e., the central region 110b. Groove 122b is formed in the edge region 112b of the land section 32, which is closer to the inner side in the vehicle width direction than the central region 110b. Groove 124b is formed in the edge region 114b of the land section 32, which is closer to the outer side in the vehicle width direction than the central region 110b. The central region 110b and the edge regions 112b and 114b are adjacent areas. The inner end of the groove 120b in the vehicle width direction is connected to the groove 122b, and the outer end of the groove 120b in the vehicle width direction is connected to the groove 124b.

[0052] Here, the inclination directions of grooves 120b, 122b, and 124b relative to the tire circumferential and tire width directions are different. That is, when grooves 120b, 122b, and 124b move from the outer side to the inner side in the vehicle width direction, their directions of movement in the tire circumferential direction are different. Here, the angle (inclination angle) formed by groove 120b and the tire circumferential direction is θ1. The angle (inclination angle) formed by groove 122b and the tire circumferential direction is θ2. The angle (inclination angle) formed by groove 124b and the tire circumferential direction is θ3. Inclination angles θ2 and θ3 are the same angle.

[0053] The groove 120b has a different inclination direction relative to the sipe 4 in both the tire circumferential and tire width directions. In other words, when the groove 120b and the sipe 4 move from the outer side to the inner side in the vehicle width direction, their directions of movement in the tire circumferential direction are different. However, when the grooves 122b and 124b move from the outer side to the inner side in the vehicle width direction, their directions of movement in the tire circumferential direction are the same as those of the sipe 4.

[0054] Figure 4 As described above, the land section 33 has sipes 4 and grooves 5 formed on its tread surface. The basic shapes of the sipes 4 and grooves 5 are the same as those of the land section 31. The grooves 5 formed in the land section 33 include grooves 120c, 122c, and 124c. The grooves 120c, 122c, and 124c are formed at different positions in the tire width direction. Groove 120c is formed in the central portion of the land section 33 in the tire width direction, i.e., the central region 110c. Groove 122c is formed in the edge region 112c of the land section 33, which is closer to the inner side in the vehicle width direction than the central region 110c. Groove 124c is formed in the edge region 114c of the land section 33, which is closer to the outer side in the vehicle width direction than the central region 110c. The central region 110c and the edge regions 112c and 114c are adjacent areas. The inner end of the groove 120c in the vehicle width direction is connected to the groove 122c, and the outer end of the groove 120c in the vehicle width direction is connected to the groove 124c.

[0055] Here, the inclination directions of grooves 120c, 122c, and 124c relative to the tire circumferential direction and the tire width direction are different. That is, when grooves 120c, 122c, and 124c move from the outer side to the inner side in the vehicle width direction, their directions of movement in the tire circumferential direction are different. Here, the angle (inclination angle) formed by groove 120c and the tire circumferential direction is θ1. The angle (inclination angle) formed by groove 122c and the tire circumferential direction is θ2. The angle (inclination angle) formed by groove 124c and the tire circumferential direction is θ3. Inclination angles θ2 and θ3 are the same angle.

[0056] The groove 120c has a different inclination direction relative to the sipe pattern 4, both in the tire circumferential and tire width directions. In other words, when the groove 120c and the sipe pattern 4 move from the outer side to the inner side in the vehicle width direction, their directions of movement in the tire circumferential direction are different. However, when the grooves 122c and 124c, and the sipe pattern 4 move from the outer side to the inner side in the vehicle width direction, their directions of movement in the tire circumferential direction are the same.

[0057] Figure 5 As described above, the land section 34 has sipes 4 and grooves 5 formed on its tread surface. The basic shapes of the sipes 4 and grooves 5 are the same as those of the land section 31. The grooves 5 formed in the land section 34 include grooves 120d, 122d, and 124d. The grooves 120d, 122d, and 124d are formed in different positions in the tire width direction. Groove 120d is formed in the central portion of the land section 34 in the tire width direction, i.e., the central region 110d. Groove 122d is formed in the edge region 112d of the land section 34, which is closer to the inner side in the vehicle width direction than the central region 110d. Groove 124d is formed in the edge region 114d of the land section 34, which is closer to the outer side in the vehicle width direction than the central region 110d. The central region 110d and the edge regions 112d and 114d are adjacent areas. The inner end of the groove 120d in the vehicle width direction is connected to the groove 122d, and the outer end of the groove 120d in the vehicle width direction is connected to the groove 124d.

[0058] Here, the inclination directions of grooves 120d, 122d, and 124d relative to the tire circumferential and tire width directions are different. That is, when grooves 120d, 122d, and 124d move from the outer side to the inner side in the vehicle width direction, their directions of movement in the tire circumferential direction are different. Here, the angle (inclination angle) between groove 120d and the tire circumferential direction is θ1. The angle (inclination angle) between groove 122d and the tire circumferential direction is θ2. The angle (inclination angle) between groove 124d and the tire circumferential direction is θ3. Inclination angles θ2 and θ3 are the same angle.

[0059] The groove 120d has a different inclination direction relative to the sipe pattern 4, both in the tire circumferential and tire width directions. In other words, when the groove 120d and the sipe pattern 4 move from the outer side to the inner side in the vehicle width direction, their directions of movement in the tire circumferential direction are different. However, when the grooves 122d and 124d, and the sipe pattern 4 move from the outer side to the inner side in the vehicle width direction, their directions of movement in the tire circumferential direction are the same.

[0060] Figure 6As described above, the land section 35 has sipes 4 and grooves 5 formed on its tread surface. The basic shapes of the sipes 4 and grooves 5 are the same as those of the land section 31. The grooves 5 formed on the land section 35 include grooves 120e, 122e, and 124e. The grooves 120e, 122e, and 124e are formed in different positions in the tire width direction. Groove 120e is formed in the central portion of the land section 35 in the tire width direction, i.e., the central region 110e. Groove 122e is formed in the edge region 112e of the land section 35, which is closer to the inner side in the vehicle width direction than the central region 110e. Groove 124e is formed in the edge region 114e of the land section 35, which is closer to the outer side in the vehicle width direction than the central region 110e. The central region 110e and the edge regions 112e and 114e are adjacent areas. The inner end of the groove 120e in the vehicle width direction is connected to the groove 122e, and the outer end of the groove 120e in the vehicle width direction is connected to the groove 124e.

[0061] Here, the inclination directions of grooves 120e, 122e, and 124e relative to the tire circumferential and tire width directions are different. That is, when grooves 120e, 122e, and 124e move from the outer side to the inner side in the vehicle width direction, their directions of movement in the tire circumferential direction are different. Here, the angle (inclination angle) between groove 120e and the tire circumferential direction is θ1. The angle (inclination angle) between groove 122e and the tire circumferential direction is θ2. The angle (inclination angle) between groove 124e and the tire circumferential direction is θ3. Inclination angles θ2 and θ3 are the same angle.

[0062] The groove 120e has a different inclination direction relative to the sipe pattern 4, both in the tire circumferential and tire width directions. In other words, when the groove 120e and the sipe pattern 4 move from the outer side to the inner side in the vehicle width direction, their directions of movement in the tire circumferential direction are different. However, when the grooves 122e and 124e, and the sipe pattern 4 move from the outer side to the inner side in the vehicle width direction, their directions of movement in the tire circumferential direction are the same.

[0063] Figure 7As described above, the land section 36 has sipes 4 and grooves 5 formed on its tread surface. The basic shapes of the sipes 4 and grooves 5 are the same as those of the land section 31. The grooves 5 formed on the land section 36 include grooves 120f, 122f, and 124f. The grooves 120f, 122f, and 124f are formed in different positions in the tire width direction. Groove 120f is formed in the central portion of the land section 36 in the tire width direction, i.e., the central region 110f. Groove 122f is formed in the edge region 112f of the land section 36, which is closer to the inner side in the vehicle width direction than the central region 110f. Groove 124f is formed in the edge region 114f of the land section 36, which is closer to the outer side in the vehicle width direction than the central region 110f. The central region 110f and the edge regions 112f and 114f are adjacent areas. The inner end of the groove 120f in the vehicle width direction is connected to the groove 122f, and the outer end of the groove 120f in the vehicle width direction is connected to the groove 124f.

[0064] Here, the inclination directions of grooves 120f, 122f, and 124f relative to the tire circumferential and tire width directions are different. That is, when grooves 120f, 122f, and 124f move from the outer side to the inner side in the vehicle width direction, their directions of movement in the tire circumferential direction are different. Here, the angle (inclination angle) formed by groove 120f and the tire circumferential direction is θ1. The angle (inclination angle) formed by groove 122f and the tire circumferential direction is θ2. The angle (inclination angle) formed by groove 124f and the tire circumferential direction is θ3. Inclination angles θ2 and θ3 are the same angle.

[0065] The groove 120f has a different inclination direction relative to the sipe pattern 4, both in the tire circumferential and tire width directions. In other words, when the groove 120f and the sipe pattern 4 move from the outer side to the inner side in the vehicle width direction, their directions of movement in the tire circumferential direction are different. However, when the grooves 122f and 124f, and the sipe pattern 4 move from the outer side to the inner side in the vehicle width direction, their directions of movement in the tire circumferential direction are the same.

[0066] As described above, the land sections 31, 32, 33, 34, 35, and 36 are all formed with sipes 4 and grooves 5. Furthermore, the grooves 120a, 120b, 120c, 120d, 120e, and 120f in the central region of the grooves 5 and the grooves 122a, 122b, 122c, 122d, 122e, 122f, 124a, 124b, 124c, 124d, 124e, and 124f in the edge regions, when moved from one side of the tire width direction to the other, move in opposite directions around the tire circumference (hereinafter, the inclination direction is also referred to as the opposite direction). Additionally, the sipes 4 and the grooves 120a, 120b, 120c, 120d, 120e, and 120f in the central region, when moved from one side of the tire width direction to the other, move in opposite directions around the tire circumference. Furthermore, when the sipe pattern 4 and the fine grooves 122a, 122b, 122c, 122d, 122e, 122f, 124a, 124b, 124c, 124d, 124e, and 124f in the edge area move from one side of the tire width direction to the other, the direction in which they move upward around the tire circumference becomes the same (hereinafter, the tilting direction is also referred to as the same direction).

[0067] Tire 1 improves both ice braking performance and snow driving performance by setting the grooves 5 to have opposite inclination directions in the central and edge regions, and setting the inclination directions of the grooves and sipes in the central region to be opposite, while setting the inclination directions of the grooves and sipes in the edge regions to be the same. Specifically, by making the sipes 4 and grooves 5 in the central regions 110a, 110b, 110c, 110d, 110e, and 110f in opposite inclination directions to form an intersecting shape, the edge grip on the ground is increased, making it less prone to slipping even on ice. In addition, by setting the inclination direction of the groove pattern 4 and the fine groove 5 in the edge regions 112a, 112b, 112c, 112d, 112e, 112f, 114a, 114b, 114c, 114d, 114e, and 114f to the same direction, the snow entering the groove pattern 4 and the fine groove 5 can be pushed out to the circumferential main groove side, which can suppress snow accumulation and improve snow performance.

[0068] Furthermore, the tire 1 of this embodiment, by having sipes 4 and grooves 5 formed on all land portions 31, 32, 33, 34, 35, and 36, and by having a shape that satisfies the aforementioned relationship, can improve both ice braking performance and snow driving performance. Additionally, the tire 1 of this embodiment, after dividing the land portions circumferentially into block shapes using transverse grooves as in land portions 31, 33, 34, 35, and 36, can improve both ice braking performance and snow driving performance by having a shape that satisfies the aforementioned relationship. The tire 1 achieves the aforementioned effects more appropriately by having the sipes 4 and grooves 5 on all land portions 31, 32, 33, 34, 35, and 36 satisfy the aforementioned relationship, but by having at least one intermediate land portion as a specific land portion that satisfies the aforementioned relationship, both ice braking performance and snow driving performance can be improved. Here, an intermediate land portion is a land portion with land portions arranged on both sides in the tire width direction. That is, a land portion with other land portions on the outer side in the tire width direction.

[0069] Here, when the width of the land portion 31, 32, 33, 34, 35, and 36 in the tire width direction is set to 100%, it is preferable that the width of the central regions 110a, 110b, 110c, 110d, 110e, and 110f is set to 60% or more and 80% or less. Similarly, when the width of the land portion 31, 32, 33, 34, 35, and 36 in the tire width direction is set to 100%, it is preferable that the width of the edge regions 112a, 112b, 112c, 112d, 112e, 112f, 114a, 114b, 114c, 114d, 114e, and 114f is set to 20% or more and 40% or less. By setting the width of the central and edge regions of the land to the range described above, it is possible to increase the difficulty of sliding on ice based on the edge effect and improve ice braking performance, and also to appropriately suppress snow accumulation, thus improving both ice braking performance and snow driving performance.

[0070] Furthermore, the inclination angle θa of the sipe pattern 4 relative to the tire circumference (the extension direction of the circumferential main groove) is preferably 45° or more and 80° or less, more preferably 55° or more and 80° or less. By setting the angle of the sipe pattern within the above range, the edge function of the sipe pattern 4 can be maintained and clogging can be suppressed.

[0071] Furthermore, the inclination angle θ1 of the central region of the groove 5 relative to the tire circumference (the extension direction of the circumferential main groove) is preferably set to 40° or more and 65° or less, more preferably 45°. By setting the angle of the groove 5 within the above range, the edge function of the groove can be maintained and clogging can be suppressed.

[0072] Furthermore, the inclination angles θ2 and θ3 of the edge region of the groove 5 relative to the tire circumference (the extension direction of the circumferential main groove) are preferably set to 50° or more and 80° or less, more preferably 70°. By setting the angle of the groove 5 within the above range, the edge function of the groove can be maintained and clogging can be suppressed.

[0073] Preferably, the groove 5 has a groove depth of 0.05 mm or more and 1.50 mm or less, a groove width of 0.10 mm or more and 0.80 mm or less, and a distance (spacing) between adjacent grooves 5 of 0.50 mm or more and 2.00 mm or less, as described above. By setting the shape of the groove 5 within the above range, it is possible to suppress the reduction in braking performance on ice and driving performance on snow, and it is also possible to suppress the reduction in braking performance on ice caused by the reduction in contact area and the reduction in block rigidity.

[0074] Preferably, the end of the central region of the groove 5 is connected to the end of the edge region. That is, the groove 5 is preferably shaped to connect one end to the other in the tire width direction of the land portion. By connecting the groove in the central region to the groove in the edge region, the water removal effect can be improved, and the braking performance on ice and the driving performance on snow can be further improved, especially in high-temperature environments.

[0075] Figure 8 This is a plan view showing the tread surface of a pneumatic tire 1a according to another embodiment. Figure 8 The tread surface 12a shown has multiple (in) extending along the tire circumference. Figure 8 Four circumferential main grooves (21a, 22a, 23a, and 24a) are arranged at predetermined intervals along the tire width direction. In this embodiment, as... Figure 8 As shown, the circumferential main grooves 21a, 22a, 23a, and 24a are arranged in the order of inner side in the vehicle width direction and outer side in the vehicle width direction. In this embodiment, two circumferential main grooves 21a and 22a are respectively located on the inner side in the vehicle width direction, and two circumferential main grooves 23a and 24a are respectively located on the outer side in the vehicle width direction. Here, the inner and outer sides in the vehicle width direction are defined as the orientation relative to the vehicle width direction when the tire 1a is mounted on the vehicle. Furthermore, the two outermost circumferential main grooves 21a and 24a in the tire width direction are defined as shoulder main grooves, and the two inner circumferential main grooves 22a and 23a in the tire width direction are defined as central main grooves.

[0076] On the tread surface 12a, four circumferential main grooves 21a, 22a, 23a, and 24a divide the surface into multiple grooves extending circumferentially along the tire (in... Figure 8The land sections are 31a, 32a, 33a, 34a, and 35a (5 columns in the middle). In this embodiment, the tread surface 12a is configured as the land section 33 without the tread surface 12.

[0077] The above-mentioned effect can also be achieved by forming sipes 4 and grooves 5 that satisfy the above relationship on the tread surface 12a.

[0078] [Example]

[0079] Next, as an example, the results of the performance tests on the tires of this embodiment are shown. In the performance tests, braking performance on ice and driving performance on snow were evaluated for various test tires. Furthermore, in the tires of this embodiment, a test tire with a tire size of 195 / 65R15 91Q was mounted on a specified rim with a rim size of 15×6.5J, and a specified air pressure was applied to the test tire. Additionally, the test tires were mounted on all wheels of a test vehicle with an engine displacement of 1800 [cc] and an FF (Front engine Front drive) configuration. Each tire was filled with air at a pressure of 250 / 240 kPa.

[0080] Indoor ice braking performance was assessed through braking tests conducted at an ice rink at 20 km / h, driven by test drivers. The results were then evaluated using an index with a baseline of 100. The evaluation showed that a higher index corresponded to a shorter braking distance and superior indoor ice braking performance.

[0081] Outdoor ice braking performance was assessed by conducting braking tests (20 km / h) on an outdoor ice surface using test drivers. The results were then evaluated using an index with a baseline of 100. The evaluation showed that a higher index corresponds to a shorter braking distance and superior outdoor ice braking performance.

[0082] Snow driving performance was assessed through a 10km driving test conducted by a test driver on an outdoor snow-covered road. The results were then evaluated using an index with a baseline of 100. The evaluation showed that a higher index correlated with better fuel consumption and braking performance, indicating superior snow driving performance.

[0083] Performance evaluation tests were conducted on conventional tires and various embodiment pneumatic tires. These conventional and embodiment tires all have sipes and grooves on the tread surface of the land portion. In the conventional tires, the sipes and grooves are inclined in the same direction. Additionally, as a comparative example, tests were conducted on a tire where the sipes and grooves on the land portion of the shoulder are inclined in opposite directions.

[0084] In the embodiments, the tires all have sipes and grooves with opposite inclination directions. Furthermore, the tires in these embodiments are configured to vary the position of the land portion, the inclination angle of the sipes, the inclination angle of the grooves, the ratio of the central to the edge regions on the tread surface of the land portion, the various sizes of the grooves, and the presence or absence of connections between the grooves in the central and edge regions, all in accordance with the shape shown.

[0085] The results of performance evaluation tests conducted using these tires are shown in Table 1.

[0086] [Table 1]

[0087]

[0088] It can be seen that, compared with the conventional example, the tire of the embodiment can improve braking performance on ice and driving performance on snow. In other words, the tire of the embodiment can balance braking performance on ice and driving performance on snow.

[0089] The embodiments of the present invention have been described above, but the present invention is not limited to the above embodiments. For example, in the above embodiments, a pneumatic tire was exemplified as a tire, but it is not limited to this, and it can also be applied to tires that are not filled with air, such as deflatable tires. In addition, the gas used to fill the pneumatic tire exemplified in the above embodiments can be inert gases such as nitrogen, argon, and helium, in addition to ordinary air or air with adjusted oxygen partial pressure.

[0090] Explanation of reference numerals in the attached figures

[0091] 1. 1a tire (pneumatic tire)

[0092] 4. 102 Groove Pattern

[0093] 10 fetal face

[0094] 12, 12a tread surface

[0095] 21 and 25 tire shoulder main groove (circumferential main groove)

[0096] 22, 23, 24 Central main slots (circumferential main slots)

[0097] 31, 36 tire shoulder land (land section)

[0098] 32, 35 Second Land Division (Land Division)

[0099] 33, 34 Central Army Department (Army Department)

[0100] 311, 321, 322, 331, 341, 351 horizontal grooves

[0101] 312, 323, 332, 342, 352 fine grooves

[0102] 104 Bending section

[0103] A1 Central Area

[0104] A2 Edge Area

[0105] AC crossover

[0106] BA, BB, BC blocks

[0107] CL tire equatorial plane

[0108] L1 groove depth

[0109] L2 slot width

[0110] L3 spacing

[0111] R Ground

[0112] T grounding terminal

Claims

1. A tire, the tire having on the tread a plurality of circumferential main grooves extending in the tire circumferential direction, a plurality of lateral grooves extending in a direction intersecting the circumferential main grooves, and a plurality of land portions divided by the circumferential main grooves and arranged in a direction intersecting the circumferential main grooves. A specific land portion, as at least one of the aforementioned land portions, comprises: a plurality of sipes extending along the contact surface in a direction intersecting the circumferential main grooves, wherein line segments connecting the ends on the same side of the tire circumferential direction are inclined relative to the tire circumferential and tire width directions; and a plurality of grooves extending in a direction intersecting the circumferential main grooves and inclined relative to the tire circumferential and tire width directions, wherein the groove depth is 1.50 mm or less. When the multiple sipes formed on the specific land surface have moved from one side of the tire width direction to the other, the line segments tilt in the same direction. In the specific land area, in the central region along the tire width direction, when moving from one side of the tire width direction to the other, the lines of the sipes and the grooves move in different directions in the tire circumferential direction. However, in the edge regions on both sides, which are further outward along the tire width direction than the central region, when moving from one side of the tire width direction to the other, the lines of the sipes and the grooves move in the same direction in the tire circumferential direction. The specific land portion includes land portions having one or more land portions on the outer side in the tire width direction. In each of the central region of the specific landmass and the edge regions of both sides, the plurality of grooves do not intersect each other.

2. The tire according to claim 1, The specific land area is a plurality of blocks divided by the circumferential main groove and the transverse groove.

3. The tire according to claim 1 or 2, For the specific land area, when the length of the direction intersecting the circumferential main channel is set to 100%, the length of the central region in the direction intersecting the circumferential main channel is more than 60% and less than 80%.

4. The tire according to claim 1 or 2, The inclination angle of the sipe pattern line segment relative to the tire circumference is more than 45° and less than 80°.

5. The tire according to claim 1 or 2, The inclination angle of the central region of the groove relative to the tire circumference is greater than 40° and less than 65°.

6. The tire according to claim 1 or 2, The inclination angle of the edge region of the groove relative to the tire circumference is more than 50° and less than 80°.

7. The tire according to claim 1 or 2, For the fine groove, the groove depth is 0.05 mm or more and 1.50 mm or less, the groove width is 0.10 mm or more and 0.80 mm or less, and the distance between adjacent fine grooves is 0.50 mm or more and 2.00 mm or less.

8. The tire according to claim 1 or 2, For the groove, the end of the central region is connected to the end of the edge region.

Images