Pneumatic tire

Abstract

To provide a pneumatic tire that improves wear resistance, snow braking performance, snow handling performance, and pattern noise performance in a well-balanced manner. A tread pattern of a pneumatic tire (10) has two or more circumferential main grooves provided in a single-side region with the tire equatorial plane (CL) as a boundary, and a plurality of land portions divided by the circumferential main grooves. A central land portion (Rc) closest to the tire equatorial plane (CL) among the plurality of land portions has a central sipe extending in the tire width direction, and the central sipe is a compound sipe having a two-dimensional portion and a three-dimensional portion provided on both sides of the tire width direction of the two-dimensional portion. An intermediate land portion (Rm) adjacent to the outside of the tire width direction of the central land portion (Rc) has an intermediate sipe extending in the tire width direction, and the intermediate sipe is a compound sipe having a two-dimensional portion provided on the inside of the tire width direction and a three-dimensional portion provided on the outside of the tire width direction of the two-dimensional portion.

Description

[0001] This application is a divisional application of Chinese patent application filed on February 21, 2020, with application number 202080015460.5 and invention title: "Pneumatic Tire". Technical Field

[0002] This invention relates to pneumatic tires. Background Technology

[0003] Patent Document 1 discloses a pneumatic tire that achieves a balance between drainage performance and resistance to uneven wear. In Patent Document 1, a recess is provided in the wall of the main groove, and sipes communicating with the recess and shallow grooves communicating away from the recess are provided. Furthermore, Patent Document 2 discloses a pneumatic tire that achieves a balance between snow performance and resistance to uneven wear. In Patent Document 2, by increasing the density of the sipes on the inner side of the vehicle and by arranging more three-dimensional sipes on the inner side of the vehicle, a balance between snow performance and resistance to uneven wear is achieved.

[0004] Existing technical documents

[0005] Patent documents

[0006] Patent Document 1: Japanese Patent Application Publication No. 2017-43208

[0007] Patent Document 2: Japanese Patent No. 5948995 Summary of the Invention

[0008] The problem that the invention aims to solve

[0009] The pneumatic tire in Patent Document 1 does not consider improving braking performance on snowy roads (i.e., snow braking performance) or handling stability on snowy roads (i.e., snow handling performance), leaving room for improvement. Furthermore, the pneumatic tire in Patent Document 2 has room for improvement in terms of tread noise performance.

[0010] The present invention was made in view of the above circumstances, and its object is to provide a pneumatic tire that provides a good balance of improved resistance to uneven wear, snow braking performance, snow handling performance and tread noise performance.

[0011] Technical solutions for solving the problem

[0012] To address the aforementioned issues and achieve the objective, one aspect of the present invention provides a pneumatic tire with a tread pattern comprising: a circumferential main groove, wherein two or more circumferential main grooves are provided on one side of the tire equatorial plane; and a plurality of land portions, which are divided by the circumferential main grooves. The central land portion, being the land portion closest to the tire equatorial plane among the plurality of land portions, has a central sipe extending along the tire width direction. This central sipe is a composite sipe having a two-dimensional portion and three-dimensional portions disposed on both sides of the two-dimensional portion in the tire width direction. The intermediate land portion, being the land portion adjacent to the outer side of the central land portion in the tire width direction, has an intermediate sipe extending along the tire width direction. This intermediate sipe is a composite sipe having a two-dimensional portion disposed inside the tire width direction and a three-dimensional portion disposed outside the two-dimensional portion in the tire width direction.

[0013] Preferably, the ratio of the total length of the three-dimensional portion of the central sipe pattern in the tire width direction to the length of the central sipe pattern in the tire width direction is 0.30 or more and 0.70 or less.

[0014] Preferably, the central groove pattern has a Z-shaped form with two bends.

[0015] Preferably, the ratio of the length of the three-dimensional portion of the intermediate sipe pattern in the tire width direction to the length of the intermediate land portion in the tire width direction is 0.25 or more and 0.80 or less.

[0016] Preferably, the intermediate sipe pattern has a Z-shape with two bends, and the ratio of the distance between the bend of the centerline near the midpoint of the tire width direction passing through the land portion and the centerline in the tire width direction to the width of the land portion in the tire width direction is 0 or more and 0.40 or less.

[0017] Preferably, the outer edge of the intermediate land portion in the tire width direction is a serrated edge with a serrated shape that periodically changes position in the tire width direction, the inner edge of the land portion in the tire width direction is a straight line, and the three-dimensional portion of the intermediate sipe pattern is connected to the serrated edge.

[0018] Preferably, the intermediate serration pattern is connected to the position of maximum amplitude in the tire width direction at the edge of the serration.

[0019] Preferably, the ratio of the minimum distance between the serrated protrusions to the maximum distance between the serrated protrusions is 0.50 or more.

[0020] Preferably, the intermediate land portion has multiple transverse grooves, and between adjacent transverse grooves there are two or more intermediate grooving patterns and three or more serrated protrusions.

[0021] Preferably, when the tire circumferential distance between the connecting parts of two or more intermediate sipes patterns located between adjacent transverse grooves and the circumferential main grooves on the inner side of the tire width direction is set as Ls1, Ls2, ..., Lsn (n is a natural number of 3 or more), Ls1 < Lsn.

[0022] Preferably, when the tire circumferential distance between the connecting portions of two or more intermediate sipes patterns located between adjacent transverse grooves and the circumferential main grooves on the inner side of the tire width direction is set as Ls1, Ls2, ..., Lsn (n is a natural number of 3 or more), and the tire circumferential distance between the protrusions of the connecting portions of multiple intermediate sipes patterns located between adjacent transverse grooves and the circumferential main grooves on the outer side of the tire width direction is set as Lz1, Lz2, ..., Lzn (n is a natural number of 3 or more), Ls1 < Lz1 and Lsn > Lzn.

[0023] Preferably, the pneumatic tire further comprises a shoulder land portion, which is the land portion outside the tire width direction of the intermediate land portion. The shoulder land portion has a shoulder sipe pattern extending along the tire width direction. The shoulder sipe pattern is a composite sipe pattern having a three-dimensional portion disposed inside the tire width direction and a two-dimensional portion disposed outside the tire width direction of the three-dimensional portion.

[0024] Preferably, the ratio of the length of the three-dimensional portion of the shoulder sipe in the tire width direction to the ground contact width of the shoulder portion in the tire width direction is 0.25 or more and 0.65 or less.

[0025] Preferably, the groove walls on both sides of the circumferential main groove between the intermediate land portion and the shoulder land portion are the walls facing the serrated edges.

[0026] Invention Effects

[0027] According to the present invention, it is possible to achieve a balanced improvement in resistance to uneven wear, snow braking performance, snow handling performance, and tread noise performance. Attached Figure Description

[0028] Figure 1 This is a cross-sectional view along the radial direction of an inflatable tire according to an embodiment of the present invention.

[0029] Figure 2 It is shown Figure 1 The diagram shows an example of a pneumatic tire tread pattern.

[0030] Figure 3 It is Figure 2 The diagram shows a magnified portion of the central landmass of the tire tread pattern.

[0031] Figure 4 It is Figure 2 The image is an enlarged view of a portion of the central land area of ​​the tire tread pattern shown.

[0032] Figure 5 This is a plan view showing an example of a knife groove pattern.

[0033] Figure 6 It is Figure 2 The image is an enlarged view of a portion of the central land area of ​​the tire tread pattern shown.

[0034] Figure 7 It is Figure 2 The image is an enlarged view of a portion of the central land area of ​​the tire tread pattern shown.

[0035] Figure 8A It is Figure 2 The diagram shows a magnified portion of the central section of the tire tread pattern.

[0036] Figure 8B It is Figure 8A A portion of the image is shown in magnification.

[0037] Figure 9A This is a diagram showing other examples of the central landmass.

[0038] Figure 9B It is Figure 9A A portion of the image is shown in magnification.

[0039] Figure 10A This is a diagram showing other examples of the central landmass.

[0040] Figure 10B It is Figure 10A A portion of the image is shown in magnification.

[0041] Figure 11 It is along Figure 2 A cross-sectional view showing the extension direction of the transverse groove.

[0042] Figure 12 It is Figure 2 The image shown is an enlarged view of a portion of the shoulder of the tire tread pattern.

[0043] Figure 13 It is shown Figure 2 The diagram shows the tilt direction of each groove pattern.

[0044] Figure 14 It is shown Figure 2 A cross-sectional view of an example of a three-dimensional composite grooving pattern.

[0045] Figure 15 It is along Figure 5 A cross-sectional view showing the direction of extension of the groove pattern. Detailed Implementation

[0046] Hereinafter, embodiments of the present invention will be described in detail based on the accompanying drawings. In the following descriptions of each embodiment, the same reference numerals are used to denote the same or equivalent components as in other embodiments, and their descriptions are simplified or omitted. The present invention is not limited to these embodiments. Furthermore, the constituent elements of each embodiment include elements that can be substituted and easily substituted by those skilled in the art, or substantially the same elements. The various modifications described in this embodiment can be arbitrarily combined within the scope readily apparent to those skilled in the art. Additionally, omissions, substitutions, or changes to the configuration can be made without departing from the spirit of the invention.

[0047] [Pneumatic tire]

[0048] Figure 1 This is a cross-sectional view along the radial direction of an inflatable tire according to an embodiment of the present invention. Figure 1 A cross-sectional view of a single-sided radial region of the tire is shown. Additionally, in Figure 1 The example shown is a radial tire for passenger cars.

[0049] The section along the radial direction of the tire refers to the section cut along a plane containing the tire's axis of rotation (not shown). Additionally, the reference numeral CL is the tire equatorial plane, which is a plane passing through the center point of the tire in the direction of the tire's axis of rotation and perpendicular to the tire's axis of rotation. The tire radial direction refers to the direction orthogonal to the axis of rotation (not shown) of the pneumatic tire 10. The inner radial direction refers to the radial direction towards the axis of rotation, and the outer radial direction refers to the radial direction away from the axis of rotation. The circumferential direction refers to the direction around the aforementioned axis of rotation. The width direction refers to the direction parallel to the aforementioned axis of rotation. The inner width direction refers to the width direction towards the tire equatorial plane CL, and the outer width direction refers to the width direction away from the tire equatorial plane CL.

[0050] The tire equatorial plane CL refers to a plane orthogonal to the axis of rotation of the pneumatic tire 10 and passing through the center of the tire width of the pneumatic tire 10. The tire width is the width of the portions located on the outer side of the tire width direction relative to each other in the tire width direction, i.e., the distance between the portions furthest from the tire equatorial plane CL in the tire width direction. The tire equatorial line refers to a line located on the tire equatorial plane CL and along the circumference of the pneumatic tire 10. In this embodiment, the tire equatorial line is labeled with the same reference numeral "CL" as the tire equatorial plane.

[0051] like Figure 1 As shown, the pneumatic tire 10 of this embodiment includes a tread portion 1 that extends in the circumferential direction of the tire and is in the shape of an annular shape, a pair of sidewall portions 2, 2 disposed on both sides of the tread portion 1, and a pair of bead portions 3, 3 disposed on the radially inner side of these sidewall portions 2.

[0052] A carcass layer 4 is provided between a pair of bead portions 3, 3. The carcass layer 4 includes multiple reinforcing cords extending radially along the tire and folding back from the inside to the outside of the tire around the bead core 5 disposed in each bead portion 3. A bead filler 6 made of a rubber composition with a triangular cross-section is disposed on the outer periphery of the bead core 5.

[0053] On the other hand, multiple belt layers 7 are embedded on the outer periphery of the carcass layer 4 at the tread portion 1. These belt layers 7 contain multiple reinforcing cords inclined relative to the tire circumference and are arranged such that the reinforcing cords intersect each other between layers. In the belt layers 7, the inclination angle of the reinforcing cords relative to the tire circumference is set, for example, in the range of 10 degrees to 40 degrees. Steel cords are preferably used as the reinforcing cords of the belt layers 7. On the outer periphery of the belt layers 7, for the purpose of improving high-speed durability, at least one belt cover layer 8 is provided, in which the reinforcing cords are arranged at an angle of, for example, 5 degrees or less relative to the tire circumference. Organic fiber cords such as nylon and aramid are preferably used as the reinforcing cords of the belt cover layer 8.

[0054] Furthermore, the above-described internal tire structure is a representative example of pneumatic tires and is not limited to this.

[0055] [Fetal face]

[0056] Figure 2 It is shown Figure 1 An unfolded diagram of an example of the tread pattern of the pneumatic tire 10 shown. Figure 1 and Figure 2 In the attached diagram, the symbol T indicates the tire contact point.

[0057] like Figure 2As shown, the pneumatic tire 10 in this example has four circumferential main grooves 11A, 11B, 12A, and 12B on the tread 1. Circumferential main grooves 12A and 12B extend circumferentially along the tire at a position outside the tire width direction on the tire equator plane CL. Circumferential main groove 11A extends circumferentially along the tire at a position closer to the tire equator plane CL than circumferential main groove 12A. Circumferential main groove 11B extends circumferentially along the tire at a position closer to the tire equator plane CL than circumferential main groove 12B.

[0058] The circumferential main grooves 11A, 11B, 12A, and 12B are circumferential grooves with wear indicators indicating the end of wear, and generally have a groove width of 5.0 mm or more and a groove depth of 7.5 mm or more. However, the groove width and groove depth of the circumferential main grooves 11A, 11B, 12A, and 12B are not limited to the above ranges.

[0059] Furthermore, the transverse groove mentioned later refers to a transverse groove with a groove width of 2.0 mm or more and a groove depth of 3.0 mm or more. Additionally, the kerf pattern mentioned later refers to a cut formed on the land surface, generally with a groove width of less than 1.5 mm.

[0060] exist Figure 2 In the tread pattern, the central land area Rc is divided by two circumferential main grooves 11A and 11B. Additionally, the intermediate land area Rm is divided by two circumferential main grooves 11A and 12A, and the other intermediate land areas Rm are divided by two circumferential main grooves 11B and 12B. The outer edge of the circumferential main groove 12A in the tire width direction becomes the shoulder land area Rs. The outer edge of the circumferential main groove 12B in the tire width direction becomes the other shoulder land areas Rs. Furthermore, when there are three circumferential main grooves, the central land area Rc is not provided; instead, the tread pattern is formed by the intermediate land areas Rm on both sides of the equator CL and the shoulder land areas Rs on the outer edge of the intermediate land areas Rm in the tire width direction.

[0061] The central land section Rc (hereinafter sometimes simply referred to as land Rc) is located on the tire equator CL. The land Rc has multiple sipes 15. The sipes 15 extend along the tire circumferential and tire width directions. One end of each sipe 15 connects to a circumferential main groove 11A, and the other end connects to a circumferential main groove 11B. The sipes 15 are continuous sipes that penetrate the land Rc. Furthermore, in this example, the edges on both sides of the land Rc are straight.

[0062] The intermediate land section Rm (hereinafter sometimes simply referred to as land section Rm) has multiple transverse grooves 13. The transverse grooves 13 extend along the tire width direction and the tire circumferential direction. One end of the transverse groove 13 on the inner side in the tire width direction opens toward the circumferential main groove 11A or 11B. The other end of the transverse groove 13 on the outer side in the tire width direction opens toward the circumferential main groove 12A or 12B. The land section Rm has a bottom raised portion 130 in the transverse groove 13. The bottom raised portion 130 is a portion that raises the bottom of the transverse groove 13, making the groove depth shallower than other portions. The bottom raised portion 130 is provided at the inner end of the transverse groove 13 in the tire width direction. Additionally, the land section Rm has multiple sipes 16 between adjacent transverse grooves 13. The sipes 16 (hereinafter sometimes referred to as intermediate sipes) extend along the tire circumferential direction and the tire width direction. One end of the groove pattern 16 is connected to the circumferential main groove 11A or 11B, and the other end of the groove pattern 16 is connected to the circumferential main groove 12A or 12B. The groove pattern 16 is a through groove pattern that penetrates the land portion Rm.

[0063] In this example, the outer edge of the land section Rm in the tire width direction, i.e., the edge on the circumferential main groove 12A or 12B side, is serrated (hereinafter sometimes referred to as a serrated edge). A serrated shape is a concave-convex shape with a periodically changing position in the tire width direction. The inner edge of the land section Rm in the tire width direction, i.e., the edge on the circumferential main groove 11A or 11B side, is a straight shape without concave-convexity.

[0064] The shoulder land portion Rs (hereinafter sometimes simply referred to as land portion Rs) has multiple lateral grooves 14A and 14B. The lateral grooves 14A and 14B extend along the tire width direction from the inside to the outside. The lateral grooves 14A and 14B extend from the circumferential main grooves 12A or 12B to the outside of the tire contact patch T. The land portion Rs has multiple sipes 17 between the lateral grooves 14A and 14B. The sipes 17 extend along the tire width direction. One end of the sipe 17 connects to the circumferential main grooves 12A or 12B, and the other end of the sipe 17 connects to a decorative groove 18 on the outside of the tire contact patch T.

[0065] In this example, the land portion Rs has bottom raised portions 140A and 140B in the transverse grooves 14A and 14B. The bottom raised portions 140A and 140B are portions that raise the bottom of the transverse grooves 14A and 14B, making the groove depth shallower than other portions. The bottom raised portions 140A and 140B are provided at the ends of the transverse grooves 14A and 14B in the tire width direction, that is, at the opening ends of the circumferential main grooves 12A and 12B.

[0066] [Knife Groove Pattern]

[0067] exist Figure 2In this design, sipes 15, 16, and 17 are composite sipe patterns having sections of two-dimensional portions (so-called planar sipe patterns) and sections of three-dimensional portions (so-called three-dimensional sipe patterns). The two-dimensional portion refers to the part of the sipe pattern wall that has a straight shape when viewed in section perpendicular to the length direction of the sipe pattern. The three-dimensional portion refers to the part of the sipe pattern wall that has a bent shape in the width direction of the sipe pattern when viewed in section perpendicular to the length direction of the sipe pattern. Through these sipes 15, 16, and 17, the edge components of the land portion Rc, Rm, and Rs are ensured, thereby improving the traction of the pneumatic tire 10.

[0068] exist Figure 2 In the diagram, the area within region 20A of the groove pattern 15 is a three-dimensional part. The area outside region 20A of the groove pattern 15 is a two-dimensional part. The area within region 20B of the groove pattern 16 is a three-dimensional part. The area outside region 20B of the groove pattern 16 is a two-dimensional part. The area within region 20C of the groove pattern 17 is a three-dimensional part. The area outside region 20C of the groove pattern 17 is a two-dimensional part.

[0069] The two-dimensional portion has a straight grooved wall surface when viewed in any cross-sectional view (including cross-sectional views in both the width and depth directions) with the groove length direction as the normal. The three-dimensional portion has a curved grooved wall surface with amplitude in the width direction when viewed in cross-sectional views with both the groove length direction and the groove depth direction as the normal. Compared to the two-dimensional portion, the three-dimensional portion has a stronger meshing force between the opposing grooved wall surfaces, thus enhancing the rigidity of the land section. By increasing the rigidity of the serrated portion of the land section, resistance to chipping damage can be improved.

[0070] Here, when focusing on the land portion Rm divided by the circumferential main grooves 11A and 12A, the edge on the side of the circumferential main groove 12A is serrated. That is, one side of the edge of the land portion Rm in the tire width direction is serrated. In addition, there is a region 20B on the side of the serrated edge. That is, the three-dimensional part of the sipe pattern 16 is connected to the serrated edge, i.e., the serrated edge. Therefore, the land portion Rm improves snow performance due to the serrated edge effect. Moreover, the sipe pattern 16 on the serrated edge side, which is connected to the circumferential main groove 12A, becomes a three-dimensional part, thus increasing the block rigidity of the serrated part and improving the resistance to chipping damage.

[0071] Furthermore, when considering the land section Rs, the edge on the side of the circumferential main groove 12A is serrated. That is, one side of the edge of the land section Rs in the tire width direction is serrated. Additionally, there is a region 20C on the side of the serrated edge. That is, the three-dimensional portion of the sipe pattern 17 connects to the serrated edge, i.e., the serrated edge. Therefore, the land section Rs improves snow performance due to the serrated edge effect. Moreover, the portion of the sipe pattern 17 on the serrated edge side that connects to the circumferential main groove 12A becomes a three-dimensional portion, thus increasing the block rigidity of the serrated portion and improving resistance to chipping damage.

[0072] When considering the circumferential main channel 12A between the land portion Rm and the land portion Rs, the channel walls on both sides of the circumferential main channel 12A become the walls facing the serrated edges. As a result, the edge effect increases, and snow performance is improved.

[0073] Furthermore, when considering the land portion Rs, a three-dimensional portion is arranged at one end of the groove pattern 17 that connects to the circumferential main grooves 12A and 12B between the land portion Rs and the land portion Rm, and a two-dimensional portion is arranged at the other end. This arrangement can improve the resistance to eccentric wear of the land portion Rm and suppress the deterioration of pattern noise caused by the increase in block rigidity.

[0074] Figure 3 It is Figure 2 The diagram shows a magnified portion of the central landmass Rc of the tire tread pattern. Figure 3 In the middle, the sipe pattern (hereinafter sometimes referred to as the central sipe pattern) 15 of the land section Rc has a two-dimensional section that crosses the tire equatorial plane CL, and a three-dimensional section 20A provided on both sides of the two-dimensional section in the tire width direction. Furthermore, in Figure 3 In the middle section, the land Rc does not have a transverse groove.

[0075] Here, the maximum width in the tire width direction of the land portion Rc is defined as Wc, and the length in the tire width direction of the three-dimensional region 20A is defined as Wc3. In this case, the ratio Wc3 / Wc is preferably 0.30 or higher and 0.70 or lower. When the ratio Wc3 / Wc is less than 0.30, sufficient block rigidity cannot be obtained, and wear resistance performance decreases, therefore this is not preferred. When the ratio Wc3 / Wc exceeds 0.70, the block rigidity on the three-dimensional side is too high, and tread noise deteriorates, therefore this is also not preferred.

[0076] The central serration pattern 15 has a roughly Z-shaped form with two bends. The roughly Z-shaped form of the central serration pattern 15 is provided in the two-dimensional part. By giving the central serration pattern 15 a roughly Z-shaped form, the edge effect is increased, and the snow performance is improved.

[0077] The central sipe 15 is a composite sipe pattern having a two-dimensional portion and three-dimensional portions disposed on both sides of the two-dimensional portion. Therefore, the three-dimensional portion of the central sipe 15 is arranged facing the two-dimensional portion of the intermediate land portion Rm. As a result, excessive reduction in block rigidity near the circumferential main grooves 11A and 11B on the equatorial surface CL side of the tire can be suppressed, and the wear resistance near the equatorial surface CL of the tire can be improved.

[0078] [Central Land]

[0079] Figure 4 It is Figure 2 The image shown is an enlarged view of a portion of the central landmass Rm of the tire tread pattern. Figure 4 In this context, the maximum width in the tire width direction of the land section Rm is set to W1. Additionally, in... Figure 4 In this context, the distance (length) in the tire width direction from the connection portion of the sipe tread pattern 16 connected to the circumferential main groove 11A to the inner end of the three-dimensional region 20B is defined as Wc1. Distance Wc1 is the length of the two-dimensional portion of the sipe tread pattern 16 in the tire width direction. Figure 4 In this context, the distance from the connection portion of the sipe tread pattern 16 connected to the circumferential main groove 12A to the end of the inner side of region 20B in the tire width direction of the three-dimensional portion is defined as Wc2. Here, the length obtained by adding length Wc1 and length Wc2 is defined as Wm. Length Wm is the length of the entire sipe tread pattern 16 in the tire width direction. In this case, the ratio Wc2 / Wm is preferably 0.25 or more and 0.80 or less. When the ratio Wc2 / Wm is less than 0.25, sufficient block stiffness cannot be obtained, and handling stability performance deteriorates, so it is not preferred. When the ratio Wc2 / Wm exceeds 0.80, the block stiffness becomes too high, and tread noise deteriorates, so it is not preferred.

[0080] Furthermore, the ratio Wc1 / Wm is preferably 0.20 or higher and 0.70 or lower. When the ratio Wc1 / Wm is less than 0.20, the block rigidity on the circumferential main groove 11A side of the grooving pattern 16 becomes too high, which is not preferred. When the ratio Wc1 / Wm exceeds 0.70, the block rigidity on the circumferential main groove 11A side of the grooving pattern 16 becomes too low, which is also not preferred.

[0081] [Z-shaped]

[0082] Figure 5 This is a plan view showing an example of the groove pattern 16. Figure 5 In the middle, one end of the groove pattern 16 is connected to the circumferential main groove 11A, and the other end is connected to the circumferential main groove 12A. (Refer to...) Figure 5In this example, the sipe pattern 16 is composed of straight sections ST1, ST2, and ST3, and bent sections C1 and C2. Straight section ST1 is located on the circumferential main groove 11A side, i.e., on the inner side in the tire width direction. Straight section ST1 connects to the inner edge of the land portion Rm in the tire width direction. Straight section ST3 is located on the circumferential main groove 12A side, i.e., on the outer side in the tire width direction. Straight section ST3 connects to the outer edge of the land portion Rm in the tire width direction. The length of straight section ST1 in its extension direction is shorter than the length of straight section ST3 in its extension direction.

[0083] One end of the straight section ST1 is connected to the circumferential main groove 11A, and the other end of the straight section ST1 is connected to one end of the bent section C1. The other end of the bent section C1 is connected to the straight section ST2. One end of the straight section ST3 is connected to the circumferential main groove 12A, and the other end of the straight section ST3 is connected to one end of the bent section C2. The other end of the bent section C2 is connected to the straight section ST2. By providing the bent section C1 between the straight sections ST1 and ST2, and the bent section C2 between the straight sections ST2 and ST3, the groove pattern 16 has a generally Z-shaped form. A Z-shaped form refers to a shape that includes at least two bent sections, and the straight sections are connected to each other through the bent sections. In addition, the Z-shaped form may also include an S-shape composed of arcs. In the following description, the straight section ST1, which is closer to the equatorial plane CL, is sometimes referred to as the inner straight section, and the straight section ST3, which is farther from the equatorial plane CL, is sometimes referred to as the outer straight section.

[0084] Figure 6 It is Figure 2 The image shown is an enlarged view of a portion of the central landmass Rm of the tire tread pattern. Figure 6 In the tire circumferential length of the serrated edge between adjacent transverse grooves 13, which are divided into blocks by multiple transverse grooves 13 penetrating the land portion Rm, L1 is defined as the length of the serrated edge between adjacent transverse grooves 13. L2 is defined as the circumferential distance between the serrated protrusions. The ratio of distance L2 to length L1, L2 / L1, is preferably 0.15 or more and 0.55 or less. When the ratio L2 / L1 is greater than 0.55, the edge effect cannot be sufficiently obtained, and snow performance is not improved, so it is not preferred. When the ratio L2 / L1 is less than 0.15, the serrated protrusions become too fine and become easily damaged, so it is not preferred. Furthermore, the circumferential length L1 of the serrated edge is measured with reference to the corner of the intersection of the transverse groove 13 and the circumferential main groove 12A.

[0085] In addition, Figure 6In this design, the maximum width in the tire width direction of the land portion Rm is defined as W1. The length (i.e., width) in the tire width direction from the connection point of the sipe tread pattern 16 to the end point K1 of the inner straight section ST1 in the tire width direction is defined as W2. In the block divided by the adjacent transverse grooves 13 of the plurality of transverse grooves 13 that penetrate the land portion Rm, the width is defined as twice the amplitude of the serrated shape in the tire width direction. The width W3 is the distance in the tire width direction between the corners 21 and 22 of the opening of the sipe tread pattern 16.

[0086] At this point, the ratio of width W2 to width W1, W2 / W1, is preferably 0.10 or higher and 0.40 or lower. When this ratio W2 / W1 is less than 0.10, the edge effect decreases, and the snow performance deteriorates, so this is not preferred. When this ratio W2 / W1 is greater than 0.40, the bend C1 becomes close to the serrated part, resulting in poor resistance to chipping and damage, so this is also not preferred.

[0087] The ratio of width W3 to width W2, W3 / W2, is preferably 0.15 or higher and 0.45 or lower. When this ratio W3 / W2 is less than 0.15, the edge effect of the serrated groove becomes smaller, and the snow performance decreases, so this is not preferred. When this ratio W3 / W2 is greater than 0.45, the drainage performance decreases, and the edge effect of the groove pattern 16 also becomes smaller, so the snow performance decreases, and this is also not preferred.

[0088] Furthermore, the ratio W3 / W1, which is the maximum width W1 in the tire width direction relative to the land portion Rm, is preferably 0.03 or more and 0.15 or less. When this ratio W3 / W1 is greater than 0.15, it hinders drainage and reduces drainage performance, so it is not preferred. When this ratio W3 / W1 is less than 0.03, no edge effect is produced, and snow performance is not improved, so it is not preferred.

[0089] In the land section Rm, it is preferable that the groove pattern 16 has two or more grooves between adjacent transverse grooves 13, and three or more serrated protrusions between adjacent transverse grooves 13. When there are fewer than two groove patterns 16 between adjacent transverse grooves 13, the number of serrated protrusions decreases, and the snow performance is not improved, so it is not preferred.

[0090] In addition, Figure 6 In this design, the straight sections ST3 of each of the multiple groove patterns 16 are parallel to each other. Here, parallel means that the angle between the two straight lines L16 obtained by extending the center lines of the two groove patterns 16 is within ±5°. When the two straight lines L16 are completely parallel, the angle between the two straight lines L16 is 0°.

[0091] Moreover, in Figure 6In this design, multiple transverse grooves 13 are parallel to each other. Here, parallel means that the angle between the two straight lines L13 obtained by extending the center lines of each of the two transverse grooves 13 is within ±5°. When the two straight lines L13 are completely parallel, the angle between the two straight lines L13 is 0°.

[0092] Figure 7 It is Figure 2 The image shown is an enlarged view of a portion of the central landmass Rm of the tire tread pattern. Figure 7 In this design, the distances between the serrated protrusions of adjacent transverse grooves 13 are respectively set as Lz1, Lz2, ..., Lzn (n is a natural number of 3 or more). Distances Lz1 and Lzn are circumferential distances of the tire measured with reference to mutually different transverse grooves 13. At this time, the ratio Lzmin / Lzmax of the shortest distance Lzmin to the longest distance Lzmax among distances Lz1 to Lzn is preferably 0.50 or more. That is, preferably, the ratio of the minimum distance between the serrated protrusions to the maximum distance between the serrated protrusions is 1.05 or more. A ratio of Lzmin / Lzmax of 0.50 or more means that the distances between the protrusions are not unequally distributed. By setting different distances with unequal distribution between the protrusions, the sound dispersion generated when the pneumatic tire 10 contacts the road surface becomes better, and the tread noise is reduced. Furthermore, the minimum value of distances Lz1, Lz2, ..., Lzn is 3.0 [mm].

[0093] In addition, Figure 7 In this design, the tire circumferential distances between the connecting portions of multiple sipes 16 located between adjacent transverse grooves 13 and the circumferential main grooves 11A on the inner side of the tire width direction are respectively designated as Ls1, Ls2, ..., Lsn (n is a natural number of 3 or more). Distances Ls1, Ls2, ..., Lsn are tire circumferential distances measured with reference to the connecting portions of the inner straight sections ST1 and the circumferential main grooves 11A. Distances Ls1 and Lsn are tire circumferential distances measured with reference to mutually different transverse grooves 13. Preferably, the relationship between distances Ls1 and Lsn is Ls1 < Lsn. That is, preferably, in the tire circumferential direction, the distance Lsn at one end is longer than the distance Ls1 at the other end. By changing the distance of the inner straight sections ST1 of the Z-shaped sipes 16, the edge effect can be utilized more extensively, improving snow performance. Furthermore, the minimum distance between Ls1, Ls2, ..., Lsn is 2.5 mm.

[0094] exist Figure 7In this design, the tire circumferential distances between the protrusions of the connecting portions of the multiple sipes 16 located between adjacent transverse grooves 13 and connected to the circumferential main groove 12A on the outer side of the tire width direction are respectively designated as Lz1, Lz2, ..., Lzn (n is a natural number of 3 or more). Distances Lz1 and Ls1 are tire circumferential distances measured with the same transverse groove 13 as a reference. Since the same transverse groove 13 is used as a reference, distances Lz1 and Ls1 are in an inner-outer relationship in the tire width direction, and they are located at corresponding positions. Similarly, distances Lzn and Lsn are tire circumferential distances measured with the same transverse groove 13 as a reference. Since the same transverse groove 13 is used as a reference, distances Lzn and Lsn are in an inner-outer relationship in the tire width direction, and they are located at corresponding positions. Preferably, Ls1 < Lz1 and Lsn > Lzn. Preferably, in the tire circumferential direction, regarding the relationship between distances Ls1 and Lz1 at corresponding positions, the distance Lz1 at the outer position in the tire width direction is greater than the distance Ls1 at the inner position in the tire width direction. By making distance Lz1 greater than distance Ls1, the extension length of the sipe pattern increases, thus increasing the edge effect and improving snow performance. Furthermore, preferably, in the tire circumferential direction, regarding the relationship between distances Lsn and Lzn at corresponding positions, the distance Lzn at the outer position in the tire width direction is smaller than the distance Lsn at the inner position in the tire width direction. By making distance Lzn smaller than distance Lsn, the extension length of the sipe pattern increases, thus increasing the edge effect and improving snow performance.

[0095] exist Figure 7 In this configuration, the sipes 16 are connected to the position of maximum amplitude W3, which is twice the width of the serrated edge in the tire width direction. Therefore, when stress is applied along the tire circumference, the stress applied to the easily damaged protrusions can be dispersed along the groove walls of the sipes 16, improving resistance to chipping damage. For example, when stress is applied along the tire circumference as shown by arrow YA, the stress can be dispersed along the groove walls of the sipes 16 as shown by arrow YB. This further improves the resistance to chipping damage to the easily damaged protrusions.

[0096] Figure 8A It is Figure 2 The diagram shows a magnified portion of the central landmass Rm of the tire tread pattern. Figure 8B It is Figure 8A A portion of the image is shown in magnification. Figure 8A and Figure 8BIn the tread pattern 16, the two bent portions C1 and C2 are positioned inside the tire width direction of the centerline RL, which passes through the center of the land portion Rm. Of the two bent portions C1 and C2, bent portion C2 is located closer to the centerline RL than bent portion C1. The boundary between bent portion C2 and straight portion ST3 is endpoint K2. The distance between endpoint K2 and the centerline RL in the tire width direction is defined as Db. The ratio of distance Db to the maximum tire width W1 of the land portion Rm, Db / W1, is preferably 0 or more and 0.40 or less.

[0097] Here, the tire circumferential length from the connection point 23 connecting the sipe pattern 16 to the circumferential main groove 11A inside the tire width direction to the endpoint K2 inside the tire width direction of the outer straight portion ST3 is defined as L3. The ratio of length L3 to length L1, L3 / L1, is preferably 0.15 or more and 0.45 or less. When the ratio L3 / L1 is greater than 0.45, the number of sipe patterns cannot be increased, so snow performance is not improved, and therefore it is not preferred. When the ratio L3 / L1 is less than 0.15, the length of the portion connecting the straight portions ST1 and ST3 extending from the two edge sides of the land portion Rm (i.e., the bend portion C1, the straight portion ST2, and the bend portion C2) becomes shorter, the edge effect decreases, and snow performance is not improved, and therefore it is not preferred.

[0098] Furthermore, the ratio of length L3 to maximum width W1, L3 / W1, is preferably 0.15 or higher and 0.65 or lower. When L3 / W1 is less than 0.15, the edge effect decreases, and snow performance deteriorates, so this is not preferred. When L3 / W1 is greater than 0.65, the number of groove patterns cannot be increased, and snow performance is not improved, so this is also not preferred.

[0099] Figure 9A This is a diagram showing other examples of the intermediate landmass Rm. Figure 9B It is Figure 9A A portion of the image is shown in magnification. Figure 9A and Figure 9B In the sipe patterns 16A and 16B, the bent portions C1 and C2 are positioned closer to the centerline RL in the tire width direction than the center of the land portion Rm. In the sipe pattern 16A, the bent portion C2 is located closer to the centerline RL than the bent portion C1. The boundary between the bent portion C2 and the straight portion ST3 is the endpoint K2. The distance between the endpoint K2 and the centerline RL in the tire width direction is defined as Dba. The ratio of the distance Dba to the maximum width W1 in the tire width direction of the land portion Rm, Dba / W1, is preferably 0 or more and 0.40 or less.

[0100] Furthermore, in the sipe pattern 16B, the bend C1 of the two bends C1 and C2 is located closer to the centerline RL than the bend C2. The boundary between the bend C1 and the straight section ST1 is the endpoint K1. The distance between the endpoint K1 and the centerline RL in the tire width direction is defined as Dbb. The ratio of the distance Dbb to the maximum width W1 in the tire width direction of the land section Rm, Dbb / W1, is preferably 0 or more and 0.40 or less.

[0101] Figure 10A This is a diagram showing other examples of the intermediate landmass Rm. Figure 10B It is Figure 10A A portion of the image is shown in magnification. Figure 10A and Figure 10B In this configuration, the bent portion C1 of the sipe pattern 16C is positioned inside the centerline RL in the tire width direction, which is closer to the centerline than the center of the land portion Rm. The bent portion C2 of the sipe pattern 16B is located on the centerline RL. More specifically, the endpoint K2, which serves as the boundary between the bent portion C2 and the straight portion ST3, is located on the centerline RL. In this case, the distance between the endpoint K2 and the centerline RL in the tire width direction is 0, therefore Db / W1 = 0. The same applies to the bent portion C2 of the sipe pattern 16D.

[0102] Therefore, in Figure 10A and Figure 10B In the case of bending portion C2 near the midpoint of the centerline RL in the tire width direction passing through the land portion Rm, the ratio of the distance of the bending portion C2 in the tire width direction of the centerline RL to the width of the land portion Rm in the tire width direction is 0 or more and 0.40 or less. Alternatively, one of the two bending portions C1 and C2 may be located inside the centerline RL in the tire width direction than the midpoint of the land portion Rm, while the other bending portion is located on the centerline RL.

[0103] By ensuring that the ratio of the distance between the bend point of the bend in one of the two bends C1 and C2, located near the midpoint of the centerline RL in the tire width direction passing through the land section Rm, and the distance in the tire width direction of the centerline RL, to the maximum width W1 of the tire width direction of the land section Rm, is 0 or more and 0.40 or less, the following effect can be achieved. Specifically, by providing serrated grooves and a roughly Z-shaped sipe pattern 16, the edge effect is increased. When the roughly Z-shaped bend point is close to the serrated portion, the block rigidity near the serrated portion decreases, potentially causing chipping damage. Therefore, by setting the bend point and the serrated portion of the sipe pattern 16 at separate positions, both snow performance and chipping resistance can be achieved.

[0104] Furthermore, the groove width is measured as the maximum distance between the left and right groove walls of the groove opening under no-load conditions, with the tire mounted on a specified rim and filled with a specified internal pressure. In structures where the land portion has a notch or chamfer at the edge, the groove width is measured based on the intersection of the extended lines of the tread surface and the groove wall when viewed in cross-section with the groove length direction as the normal direction. Additionally, in structures where the groove extends in a serrated or wavy pattern along the tire circumference, the groove width is measured based on the center line of the groove wall's amplitude.

[0105] The tire contact point T is defined as the position of the maximum axial width of the tire at the contact surface between the tire and the flat plate when the tire is mounted on a specified rim, subjected to 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.

[0106] Here, the rim is defined as the "rim" as specified by JATMA. (Applicable rim)", "Design Rim" as specified by TRA, or "Measuring Rim" as specified by ETRTO. Additionally, the specified internal pressure refers to the "JATMA" standard. (Maximum tire pressure), the maximum value of "TIRE LOAD LIMITS AT VARIOUSCOLD INFLATION PRESSURES" as specified by TRA, or "INFLATION PRESSURES" as specified by ETRO. Additionally, the specified load refers to the "JATMA" specification. The maximum load capacity is specified by TRA as “TIRE LOAD LIMITS AT VARIOUS COLDINFLATION PRESSURES” or ETRTO as “LOAD CAPACITY”. However, in JATMA, for passenger car tires, the specified internal pressure is 180 kPa and the specified load is 88% of the maximum load capacity.

[0107] [The relationship between the groove pattern and the raised bottom of the transverse groove]

[0108] Here, the two-dimensional portion of the sipe pattern 16 in the land portion Rm is provided at the end of the sipe pattern 16 on the inner side in the tire width direction. On the other hand, the three-dimensional portion of the sipe pattern 16 in the land portion Rm is provided at the end of the sipe pattern 16 on the outer side in the tire width direction. In addition, as described above, in the land portion Rm, the bottom raised portion 130 of the transverse groove 13 is provided at the opening end on the inner side in the tire width direction of the transverse groove 13. Therefore, the bottom raised portion 130 is provided at the opening end on both sides of the transverse groove 13, on the same side as the end of the sipe pattern 16 with the two-dimensional portion. In the transverse groove 13, the bottom raised portion 130 is provided at the end on the same side as the end of the sipe pattern with the two-dimensional portion, which has lower rigidity than the three-dimensional portion. By providing the bottom raised portion 130 for improving rigidity at the end on the side of the two-dimensional portion with lower rigidity, the rigidity can be made uniform in the tire circumferential direction.

[0109] Furthermore, the opening ends on both sides of the transverse groove 13, on the same side as the end of the sipe 16 with the three-dimensional portion, do not have a bottom rise portion. Since the bottom rise portion 130 is only provided at the end inside the tire width direction where the two-dimensional portion is provided, and the bottom rise portion is not provided at the end outside the tire width direction where the three-dimensional portion is provided, the reduction in drainage performance can be suppressed.

[0110] Furthermore, depending on the manufacturing process of the pneumatic tire 10, sometimes a straight sipe wall surface is provided on the outer side of the three-dimensional portion in the tire width direction. This straight-shaped portion is considered part of the three-dimensional portion in any cross-sectional view (including both the sipe width and depth directions) with the sipe length direction as the normal. This straight-shaped portion is included in the three-dimensional portion. In other words, the straight-shaped sipe wall surface extending for 15% of the sipe length from the outer end of the sipe 16 in the tire width direction is considered part of the three-dimensional portion.

[0111] Figure 11 This is a cross-sectional view along the extension direction of the transverse groove 13. The ratio DL / Dg of the groove depth DL of the transverse groove 13 to the groove depth Dg of the circumferential main groove 11A is preferably 0.50 or more and 0.85 or less. When the ratio DL / Dg is greater than 0.85, the block rigidity decreases and the wear resistance decreases, so it is not preferred. When the ratio DL / Dg is less than 0.50, the snow performance decreases, so it is not preferred.

[0112] like Figure 11As shown, a bottom riser 130 is provided at the connection between the transverse groove 13 and the circumferential main groove 11A. The ratio of the groove depth of the portion with the bottom riser 130 to the groove depth of the portion without the bottom riser 130, that is, the ratio of the groove depth Du of the transverse groove 13 at the bottom riser 130 to the groove depth DL of the transverse groove 13, Du / DL, is preferably 0.40 or more and 0.80 or less. When the ratio Du / DL is less than 0.40, the drainage performance decreases, so it is not preferred. When the ratio Du / DL exceeds 0.80, sufficient block rigidity cannot be obtained, and the wear resistance performance decreases, so it is not preferred.

[0113] exist Figure 11 In the middle, the groove depth DL of the transverse groove 13 is 80% of the depth ( Figure 11 The single-dot dashed line in the image is set to a depth of 0.8DL. The length of the bottom riser 130 at depth 0.8DL in the tire width direction is set to Wu. The length Wu of the bottom riser 130 in the tire width direction is relative to the maximum width W1 of the land section Rm in the tire width direction (refer to...). Figure 4 The ratio of Wu / W1 is preferably 0.15 or higher and 0.50 or lower. When the ratio Wu / W1 is less than 0.15, sufficient block rigidity cannot be obtained, and the resistance to eccentric wear deteriorates, so it is not preferred. When the ratio Wu / W1 exceeds 0.50, the block rigidity of the three-dimensional part of the groove pattern 16 becomes too high, and the resistance to eccentric wear deteriorates, so it is not preferred.

[0114] [Fetal shoulder, land area]

[0115] Figure 12 It is Figure 2 The image shown is an enlarged view of a portion of the tire shoulder Rs, as depicted in the tread pattern. Figure 12 In this design, the land portion Rs on the outer side of the circumferential main groove 12B in the tire width direction has a sipe pattern (hereinafter sometimes referred to as a shoulder sipe pattern) 17. The length (i.e., width) of the three-dimensional portion of the sipe pattern 17 in the tire width direction is defined as Ws2. The length Ws2 is the length (i.e., width) in the tire width direction from the edge of the circumferential main groove 12B of the land portion Rs to the end of the three-dimensional portion of the sipe pattern 17 on the outer side of the tire width direction. Furthermore, the length from the edge of the circumferential main groove 12B of the land portion Rs to the contact end T, i.e., the contact width of the land portion Rs in the tire width direction, is defined as Ws1. In this case, the ratio Ws2 / Ws1 is preferably 0.25 or more and 0.65 or less. When the ratio Ws2 / Ws1 is less than 0.25, sufficient block rigidity cannot be obtained, and the resistance to uneven wear deteriorates. When the ratio Ws2 / Ws1 exceeds 0.65, the block rigidity on the three-dimensional side becomes too high, and the tread noise deteriorates, which is therefore not preferred.

[0116] exist Figure 12In the tire, the land section Rs has a plurality of shoulder transverse grooves 14A, 14B extending from the inner side of the circumferential main groove 12B in the tire width direction toward the outer side in the tire width direction. The plurality of shoulder transverse grooves 14A, 14B preferably extend at least to the ground contact end T. By extending the plurality of shoulder transverse grooves 14A, 14B to the ground contact end T, drainage performance can be improved.

[0117] A bottom riser 140A is provided at the opening end of the circumferential main groove 12B of the shoulder transverse groove 14A. Similarly, a bottom riser 140B is provided at the opening end of the circumferential main groove 12B of the shoulder transverse groove 14B. By utilizing the region 20C of the three-dimensional portion between the shoulder transverse groove 14A and the shoulder transverse groove 14B, the rigidity is increased. In contrast, by providing the bottom riser 140A and bottom riser 140B at the opening end of the circumferential main groove 12B, where the rigidity tends to decrease, uniform rigidity can be achieved in the tire circumferential direction.

[0118] In the land section Rs, the circumferential length of the serrated edge between adjacent shoulder transverse grooves 14A and 14B is defined as Ls1. Furthermore, the circumferential distance between the serrated protrusions is defined as Ls2. In this case, the ratio of Ls2 / Ls1 is preferably 0.15 or more and 0.55 or less. When the ratio of Ls2 / Ls1 is less than 0.15, the serrated protrusions become too fine and easily damaged, which is therefore undesirable. When the ratio of Ls2 / Ls1 exceeds 0.55, the edge effect cannot be sufficiently obtained, and snow performance is not improved.

[0119] Furthermore, in the land section Rs, the contact patch width in the tire width direction is defined as Ws1. Additionally, in the land section Rs, the length of twice the amplitude of the serrated edge in the tire width direction of the circumferential main groove 12B is defined as Ws3. The length Ws3 is the tire width length (i.e., width) of the serrated protrusion. In this case, the ratio Ws2 / Ws1 is preferably 0.02 or more and 0.15 or less. When the ratio Ws2 / Ws1 is less than 0.02, no edge effect occurs, and snow performance is not improved. When the ratio Ws2 / Ws1 exceeds 0.15, drainage is hindered, and drainage performance decreases.

[0120] Furthermore, the above description describes the land portion Rs on the outer side of the circumferential main groove 12B in the tire width direction, but the same description also applies to the land portion Rs on the outer side of the circumferential main groove 12A in the tire width direction.

[0121] [The direction of inclination of each groove pattern]

[0122] Figure 13 This is an explanation Figure 2 The diagram shows the tilt direction of each groove pattern. Figure 13 Will Figure 2 A portion of it is shown magnified. Figure 13In the tire configuration, the central sipe 15 located in the central land area Rc has an inclination direction relative to the tire circumference as indicated by arrow YC. Conversely, the central sipes 16 and 16 located in the intermediate land area Rm have inclination directions relative to the tire circumference as indicated by arrows YM1 and YM2, respectively. Therefore, the central sipes 16 and 16 located in the intermediate land area Rm have the same inclination direction. The inclination directions of the central sipes 16 and 16 are different from those of the central sipe 15 located in the central land area Rc. By making the sipes inclination directions different in the intermediate land area Rm and the central land area Rc, an edge effect in other directions is generated, thereby improving snow handling performance.

[0123] [Three-dimensional part of composite grooving pattern]

[0124] Figure 14 It is shown Figure 2 A cross-sectional view of an example of the three-dimensional part of the composite groove pattern 16 in the image. Figure 14 This is a diagram showing a cross-section obtained by cutting a section of the three-dimensional portion of the composite grooving pattern 16 with a plane orthogonal to the extension direction (i.e., the length direction) of the grooving pattern. Figure 14 In the composite groove pattern 16, the length of the groove pattern depth from the opening end 9A of the tread surface to the groove bottom 9B, i.e., the groove depth, is DS. The groove width (i.e., the groove pattern width) of the composite groove pattern 16 is Ts.

[0125] The area near the opening end 9A of the composite grooving pattern 16 forms a straight portion 9 along the depth direction of the grooving pattern. The composite grooving pattern 16 is formed in a curved or bent shape relative to the depth direction of the grooving pattern. The amplitude of the curved or bent grooving pattern in the width direction of the grooving pattern, centered on the line 9L obtained by extending the center line of the straight portion 9, is denoted as As. The ratio of amplitude As to groove width Ts, As / Ts, is preferably 0.40 or more and 0.80 or less. When the ratio As / Ts exceeds 0.80, the mold release properties during vulcanization molding deteriorate, leading to failure, which is therefore undesirable. When the ratio As / Ts is less than 0.40, collapse cannot be suppressed, block rigidity is not increased, and therefore wear resistance is not improved, which is also undesirable.

[0126] In addition, Figure 14 In the composite grooving pattern 16, one cycle of bending or folding is S. The composite grooving pattern 16 preferably has a bending or folding shape with more than one cycle and less than three cycles. When it is less than one cycle, the effect of suppressing collapse is insufficient, and the block rigidity does not increase, so it is not preferred. When it exceeds three cycles, the mold release property during vulcanization molding deteriorates, leading to failure, so it is also not preferred.

[0127] also, Figure 2 The other composite grooving patterns 15 and 17 also have the same structure as the composite grooving pattern 16 mentioned above.

[0128] [groove depth]

[0129] Figure 15 It is along Figure 5 A cross-sectional view of the extension direction of the 16 groove pattern. Figure 15 The illustrations are presented without distinguishing between two-dimensional and three-dimensional parts. The ratio DS / Dg of the groove depth DS of the groove pattern 16 to the groove depth Dg of the circumferential main groove 11A is preferably 0.50 or higher and 0.85 or lower. When the ratio DS / Dg is greater than 0.85, the block rigidity decreases, and the wear resistance decreases, therefore it is not preferred. When the ratio DS / Dg is less than 0.50, the edge effect is insufficient, and the snow performance decreases, therefore it is not preferred.

[0130] like Figure 15 As shown, a bottom raised portion 160 is provided at the connection point between the groove pattern 16 and the circumferential main groove 11A. The bottom raised portion 160 is a bottom raised portion of the groove pattern 16. The ratio DS1 / DS of the groove depth DS1 of the groove pattern 16 at the bottom raised portion 160 to the groove depth DS of the groove pattern 16 is preferably 0.50 or more and 0.85 or less. When the ratio DS1 / DS is greater than 0.85, the block rigidity decreases and the wear resistance decreases, so it is not preferred. When the ratio DS1 / DS is less than 0.50, the edge effect is insufficient and the snow performance decreases, so it is not preferred.

[0131] The same applies to the sipes 15 on the central landmass Rc and the sipes 17 on the shoulder landmass Rs. The ratio of the groove depth of each sipe 15 and 17 to the groove depth Dg of the circumferential main groove 11A is preferably 0.50 or higher and 0.85 or lower. When this ratio is greater than 0.85, the block rigidity decreases, and the wear resistance decreases, therefore it is not preferred. When this ratio is less than 0.50, the edge effect is insufficient, and the snow performance decreases, therefore it is not preferred.

[0132] [Example]

[0133] Tables 1 to 4 show the results of performance tests on the pneumatic tires of the present invention. In these performance tests, different pneumatic tires were evaluated in relation to eccentric wear resistance, snow braking performance, snow handling performance, and water drainage performance. In these performance tests, a 225 / 65R17 102H test tire was mounted on a 17×7.0J rim and inflated to 230 kPa. Furthermore, a 2500 cc FF (Front engine Front drive) SUV (Sport Utility Vehicle) was used as the test vehicle.

[0134] In the evaluation related to resistance to uneven wear, the test vehicle traveled 10,000 km on paved roads, and then the wear on the central land area and the wear on the shoulder land area were measured to calculate the uneven wear ratio. The uneven wear ratio was evaluated using an index (100) based on the existing example described below. A higher index value is preferred.

[0135] Snow braking performance is evaluated by indexing the braking distance at 30 km / h on snowy surfaces. This evaluation uses an index (100) as a baseline, as described below. A higher index indicates better performance.

[0136] Snow handling performance is evaluated by indexing the test driver's perception of handling stability on snowy surfaces. This evaluation uses an index (100) as a baseline, as described below. A higher index indicates better performance.

[0137] The noise performance of the pattern is evaluated by measuring the in-vehicle sound in a vehicle traveling at 100 km / h. The entire frequency band of the in-vehicle sound is considered. The evaluation is based on a noise measurement value (dB) at a baseline of 0 dB, as described below. A lower value is preferred.

[0138] The pneumatic tires of Examples 1 to 18 are tires having two or more circumferential main grooves provided on one side of the tire's equatorial plane, and multiple landmasses divided by the circumferential main grooves. Furthermore, the central landmass closest to the tire's equatorial plane among the multiple landmasses has a central sipe extending along the tire's width direction. This central sipe is a composite sipe having a two-dimensional portion and three-dimensional portions provided on both sides of the two-dimensional portion in the tire's width direction. Moreover, the intermediate landmass adjacent to the outer side of the central landmass in the tire's width direction has an intermediate sipe extending along the tire's width direction. This intermediate sipe is Z-shaped and is a composite sipe having a two-dimensional portion provided on the inner side of the two-dimensional portion in the tire's width direction and a three-dimensional portion provided on the outer side of the two-dimensional portion in the tire's width direction.

[0139] In the pneumatic tires of Examples 1 to 18, settings were configured as shown in Tables 1 to 4. Specifically, pneumatic tires were prepared with the following: a central sipe with a 2D sipe pattern at the center and 3D sipe patterns at both ends; a central sipe pattern with a length Wc3 of 2D sipe pattern relative to the overall length Wc of the central sipe pattern (Wc3 / Wc) of 0.30 or more and 0.70 or less; a central sipe pattern with a 2D sipe pattern on the inner side of the tire width direction and 3D sipe patterns at both ends; a central sipe pattern with a length Wc2 of 2D sipe pattern relative to the overall length Wm of the central sipe pattern (Wc2 / Wm) of 0.25 or more and 0.80 or less; and a pneumatic tire without these features. Pneumatic tires with the following characteristics are eligible for the following tire classification: Pneumatic tires with a Z-shaped sipe in the center tread pattern, where the distance between the sipe near the midpoint of the centerline in the tire width direction and the centerline is relative to the width of the centerline in the tire width direction (Db / W1) is 0 or more and 0.40 or less, and tires that do not meet these criteria; pneumatic tires with a 3D sipe pattern on the inner side of the shoulder sipe pattern and 2D sipe patterns at both ends, and tires that do not meet these criteria; and pneumatic tires with a length Ws2 of the three-dimensional portion of the shoulder sipe pattern relative to the overall length Ws1 of the shoulder sipe pattern (Ws2 / Ws1) being 0.25 or more and 0.65 or less, and tires that do not meet these criteria. Furthermore, pneumatic tires with a minimum distance between serrated protrusions relative to a maximum distance between serrated protrusions (Lzmin / Lzmax) being 0.50 or more.

[0140] The existing pneumatic tires are tires with a 2D sipe pattern on the land surface. Comparative Example 1's pneumatic tire has a 3D sipe pattern on the land surface. Comparative Example 2's pneumatic tire has a 3D sipe pattern in the center of the central sipe and 2D sipe patterns on both sides; the inner side of the central sipe in the tire width direction has a 2D sipe pattern and the outer side has a 3D sipe pattern; and the inner side of the shoulder sipe in the tire width direction has a 3D sipe pattern and the outer side has a 2D sipe pattern. Comparative Example 3's pneumatic tire has a 2D sipe pattern in the center of the central sipe and 3D sipe patterns on both sides; the inner side of the central sipe in the tire width direction has a 3D sipe pattern and the outer side has a 2D sipe pattern; and the inner side of the shoulder sipe in the tire width direction has a 3D sipe pattern and the outer side has a 2D sipe pattern. Comparative Example 4 is a tire with a central sipe pattern of 2D sipes on the center and 3D sipes on both sides, a central sipe pattern with 2D sipes on the inner side and 3D sipes on the outer side in the tire width direction, and a shoulder sipe pattern with 2D sipes on the inner side and 3D sipes on the outer side in the tire width direction.

[0141] Furthermore, in Tables 1 to 4, "2D" for the groove pattern shape indicates that the groove pattern is composed only of two-dimensional parts. "3D" for the groove pattern shape indicates that the groove pattern is composed only of three-dimensional parts. "2D+3D" for the groove pattern shape indicates a composite groove pattern composed of two-dimensional and three-dimensional parts.

[0142] For these pneumatic tires, the above evaluation methods were used to evaluate their resistance to uneven wear, snow braking performance, snow handling performance, tread noise performance, and drainage performance. The results are shown in Tables 1 to 4.

[0143] As shown in Tables 1 to 4, the following cases are considered: 1) The central sipe has a 2D sipe at its center and 3D sipes at both ends; 2) The ratio of the length Wc3 of the three-dimensional portion of the central sipe to the overall length Wc of the central sipe (Wc3 / Wc) is 0.30 or more and 0.70 or less; 3) The inner side of the intermediate sipe in the tire width direction has a 2D sipe and 3D sipes at both ends; 4) The ratio of the length Wc2 of the three-dimensional portion of the intermediate sipe to the overall length Wm of the intermediate sipe (Wc2 / length Wm) is 0.25 or more and 0.80 or less; 5) The intermediate sipe has two Z-shaped bends, one closer to the center section in the tire width direction. Good results were obtained when the ratio of the distance between the bend of the centerline at the midpoint and the centerline in the tire width direction to the width of the middle section in the tire width direction, Db / W1, was 0 or more and 0.40 or less; when the ratio of the minimum distance between the serrated protrusions to the maximum distance between the serrated protrusions, Lzmin / Lzmax, was 0.50 or more; when the inner side of the shoulder sipe pattern in the tire width direction was a 3D sipe pattern and its two ends were 2D sipe patterns; and when the ratio of the length Ws2 of the three-dimensional part of the shoulder sipe pattern to the overall length Ws1 of the shoulder sipe pattern, Ws2 / Ws1, was 0.25 or more and 0.65 or less.

[0144] [Table 1]

[0145]

[0146] [Table 2]

[0147]

[0148] [Table 3]

[0149]

[0150] [Table 4]

[0151]

[0152] Explanation of reference numerals in the attached figures

[0153] 1. Fetal face

[0154] 2. Side of the tire

[0155] 3. Bead area

[0156] 4. Fetal body layers

[0157] 5. Bead core

[0158] 6. Bead filling

[0159] 7. Belt layer

[0160] 8. Belt Covering Layer

[0161] 10 Pneumatic tires

[0162] 11A, 11B, 12A, 12B Circumferential Main Slots

[0163] 13 horizontal slot

[0164] 14A, 14B transverse slots

[0165] 15, 16, 17 Groove pattern

[0166] 18 Decorative slots

[0167] 130, 140A, 140B, 160 Bottom Height Increase

[0168] As amplitude

[0169] CL tire equatorial plane

[0170] Rc Central Land Division

[0171] Rm Intermediate Land

[0172] Rs Shoulder Land

[0173] T tire grounding terminal

[0174] Ts slot width

Claims

1. A pneumatic tire, wherein the pneumatic tire is a pneumatic tire with a tread pattern, characterized in that, The tread pattern includes: circumferential main grooves, wherein two or more circumferential main grooves are provided on one side of the tire's equatorial plane; and multiple land portions, wherein the multiple land portions are divided by the circumferential main grooves. The central land portion, which is the land portion closest to the tire's equatorial plane among the plurality of land portions, has a central sipe pattern extending along the tire's width direction. The central sipe pattern is a composite sipe pattern having a two-dimensional portion and three-dimensional portions disposed on both sides of the two-dimensional portion in the tire width direction. The middle land portion, which is adjacent to the outer side of the central land portion in the tire width direction, has a central sipe pattern extending in the tire width direction. The intermediate sipe pattern is a composite sipe pattern having a two-dimensional portion disposed inside the tire width direction and a three-dimensional portion disposed outside the tire width direction of the two-dimensional portion. The central groove pattern is a through groove pattern that runs through the central land area. The central groove pattern has a Z-shaped design with two bends. The two Z-shaped bends of the central groove pattern are located in the two-dimensional portion of the central groove pattern. The two-dimensional portion of the central sipe pattern traverses the tire's equatorial plane. The intermediate groove pattern is a through groove pattern that runs through the intermediate land portion. The central groove pattern has a Z-shaped design with two bends. The two Z-shaped bends of the intermediate groove pattern are located in the two-dimensional portion of the intermediate groove pattern. The outer edge of the intermediate land section in the tire width direction is a serrated edge with a periodically changing position in the tire width direction. The inclination direction of the intermediate sipes is different from that of the central sipes. The Z-shape of the central sipe and the Z-shape of the intermediate sipe bend in opposite directions in the tire circumference, facing one direction towards the tire width. The intermediate groove pattern has a straight section, and the straight sections of each of the plurality of intermediate groove patterns are parallel to each other. The central landmass does not have transverse grooves. The intermediate land section has a transverse groove that runs through it. The transverse groove of the intermediate land section has a raised bottom at the opening end inside the tire width direction. The inner edge of the shoulder land portion, which is adjacent to the outer side of the intermediate land portion in the tire width direction, is a serrated edge with a serrated shape that periodically changes in position in the tire width direction.

2. The pneumatic tire according to claim 1, characterized in that, The ratio of the total length of the three-dimensional portion of the central sipe pattern in the tire width direction to the length of the central sipe pattern in the tire width direction is 0.30 or more and 0.70 or less.

3. The pneumatic tire according to claim 1 or 2, characterized in that, The central groove pattern has a Z-shaped design with two bends. The ratio of the distance between the centerline of the two bends that is close to the midpoint of the tire width direction passing through the land portion and the centerline in the tire width direction to the width of the land portion in the tire width direction is 0 or more and 0.40 or less.

4. The pneumatic tire according to claim 1 or 2, characterized in that, The intermediate serration pattern is connected to the position of maximum amplitude in the tire width direction at the edge of the serration.

5. The pneumatic tire according to claim 1 or 2, characterized in that, The ratio of the minimum distance between the serrated protrusions to the maximum distance between the serrated protrusions is greater than 0.

50.

6. The pneumatic tire according to claim 1 or 2, characterized in that, The intermediate land portion has multiple transverse grooves, and between adjacent transverse grooves there are two or more intermediate grooving patterns and three or more serrated protrusions.

7. The pneumatic tire according to claim 6, characterized in that, When the circumferential distance between the connecting parts of two or more intermediate sipes patterns located between adjacent transverse grooves and the circumferential main grooves on the inner side of the tire width direction are set as Ls1, Ls2, ..., Lsn, Ls1 < Lsn, and n is a natural number of 3 or more.

8. The pneumatic tire according to claim 6, characterized in that, When the tire circumferential distance between the connecting parts of two or more intermediate sipes patterns located between adjacent transverse grooves and the circumferential main grooves on the inner side of the tire width direction is set as Ls1, Ls2, ..., Lsn, and the tire circumferential distance between the protrusions of multiple intermediate sipes patterns located between adjacent transverse grooves and the circumferential main grooves on the outer side of the tire width direction is set as Lz1, Lz2, ..., Lzn, Ls1 < Lz1 and Lsn > Lzn, and n is a natural number of 3 or more.

9. The pneumatic tire according to claim 1 or 2, characterized in that, The pneumatic tire also has a shoulder land portion, which is the land portion on the outer side of the central land portion in the tire width direction. The shoulder land portion has shoulder sipes extending along the tire width direction. The shoulder sipes are a composite sipe pattern comprising a three-dimensional portion disposed on the inner side of the tire width direction and a two-dimensional portion disposed on the outer side of the three-dimensional portion in the tire width direction.

10. The pneumatic tire according to claim 9, characterized in that, The ratio of the length of the three-dimensional portion of the shoulder sipe in the tire width direction to the ground contact width of the shoulder portion in the tire width direction is 0.25 or more and 0.65 or less.

11. The pneumatic tire according to claim 9, characterized in that, The groove walls on both sides of the circumferential main groove between the intermediate land portion and the shoulder land portion are the walls facing the serrated edges.

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