tire

Abstract

The present invention aims to improve wet braking performance and wear resistance. A tire includes: at least three main grooves provided in a tread portion; a circumferential narrow groove provided on the vehicle outer side of the first main groove (i.e., the first main groove) when the tire is mounted on a vehicle and extending in the tire circumferential direction; and a first sipe provided in a first intermediate land portion between the first main groove and the circumferential narrow groove, the circumferential narrow groove having a zigzag chamfered portion. The first sipe includes: a first inclined portion curved at a curved portion provided between the first main groove and the circumferential narrow groove, provided on one side of the curved portion in the tire width direction, inclined relative to the tire circumferential direction, and opening into the first main groove; and a second inclined portion provided on the other side of the curved portion in the tire width direction, inclined toward the side opposite to the first inclined portion, and terminating between the curved portion and the circumferential narrow groove, the zigzag chamfered portion provided on an extension of a centerline of the second inclined portion.

Description

Technical Field

[0001] The present invention relates to tires. Background Art

[0002] In tires, achieving both wet braking performance and wear resistance is crucial. In the tire described in Patent Document 1, sipes having curved portions are provided on the land portion on the vehicle's outer side relative to the tire's equatorial plane. In the tires described in Patent Documents 2 and 3, sipes having curved portions are provided on the land portion on both outer sides in the tire width direction relative to the tire's equatorial plane.

[0003] Prior art literature

[0004] Patent Literature

[0005] Patent Document 1: Japanese Patent Application Laid-Open No. 2017-124712

[0006] Patent Document 2: Japanese Patent Application Laid-Open No. 2017-124713

[0007] Patent Document 3: Japanese Patent Application Laid-Open No. 2017-193337 Summary of the Invention

[0008] Problems to be solved by the invention

[0009] However, the tires described in Patent Documents 1 and 2 have room for improvement in terms of achieving both wet braking performance and wear resistance.

[0010] The present invention has been made in view of the above-mentioned circumstances, and an object of the present invention is to provide a tire capable of improving wet braking performance and wear resistance.

[0011] Means for solving problems

[0012] In order to solve the above-mentioned problems and achieve the purpose, a tire of one embodiment of the present invention includes: at least three main grooves, the at least three main grooves being provided in the tread portion; a circumferential fine groove, the circumferential fine groove being provided on the vehicle outer side of the first main groove, i.e., the first main groove, when installed on a vehicle and extending in the tire circumferential direction; and a first sipe, the first sipe being provided in a first intermediate land portion between the first main groove and the circumferential fine groove, the circumferential fine groove having a serrated chamfered portion, i.e., a serrated chamfered portion, provided on a side surface on the side of the first intermediate land portion, the first sipe The first sipe pattern is bent at a curved portion provided between the first main groove and the circumferential fine groove, and has: a first inclined portion, the first inclined portion being provided on one side of the curved portion in the tire width direction and inclined relative to the tire circumferential direction and opening to the first main groove; and a second inclined portion being provided on the other side of the curved portion in the tire width direction and inclined relative to the tire circumferential direction to a side opposite to the first inclined portion and terminating between the curved portion and the circumferential fine groove, the serrated chamfer being provided on an extension line of a center line of the second inclined portion.

[0013] Preferably, the maximum width position of the serrated chamfered portion is provided within a range of ±10 degrees from an extension line of the second inclined portion with reference to the terminal end position of the second inclined portion.

[0014] Preferably, a ratio SW1 / L1 of an extension length SW1 of the first sipe in the tire width direction to a land portion width L1 of the first middle land portion is 0.7 or more and 0.9 or less.

[0015] Preferably, one end of the first inclined portion is open to the first main groove, the first inclined portion has a first chamfered portion provided at a portion of the side surface on the way from the one end to the curved portion, and the ratio MW1 / SW1 of the extension length MW1 of the first chamfered portion in the tire width direction to the extension length SW1 of the first sipe pattern in the tire width direction is greater than 0.2 and less than 0.4.

[0016] It may also include: a second intermediate land portion, the second intermediate land portion being arranged between the second main groove, i.e., the second main groove, and the third main groove, i.e., the third main groove, from the outer side of the vehicle when installed on the vehicle; and a second sipe pattern, the second sipe pattern being arranged in the second intermediate land portion and extending along the circumferential direction of the tire, one end of the second sipe pattern opening to the third main groove, the other end of the second sipe pattern terminating in the second intermediate land portion, the second sipe pattern bending on the way from the one end to the other end, and the second sipe pattern having a second chamfered portion arranged at a part of the side surface on the way from the one end to the other end.

[0017] Preferably, a ratio SW2 / L2 of an extension length SW2 of the second sipe in the tire width direction to a land portion width L2 of the second middle land portion is 0.6 or more and 0.8 or less.

[0018] Preferably, a ratio MW2 / SW2 of an extension length MW2 of the second chamfered portion in the tire width direction to an extension length SW2 of the second sipe in the tire width direction is 0.4 or more and 0.6 or less.

[0019] It may also include: a third intermediate land portion, the third intermediate land portion being arranged between the first main groove, i.e., the first main groove, and the second main groove, i.e., the second main groove, from the outer side of the vehicle when installed on the vehicle; and a third sipe pattern, the third sipe pattern being arranged in the third intermediate land portion and extending along the circumferential direction of the tire, one end of the third sipe pattern opening to the second main groove, the other end of the third sipe pattern terminating in the third intermediate land portion, the third sipe pattern bending on the way from the one end to the other end, and the third sipe pattern having second chamfered portions on both side surfaces on the way from the one end to the other end.

[0020] Preferably, a ratio SW3 / L3 of an extension length SW3 of the third sipe in the tire width direction to a land portion width L3 of the third middle land portion is 0.5 or more and 0.7 or less.

[0021] It may also include: an inner shoulder land portion, the inner shoulder land portion being arranged on the inner side of the vehicle of the 4th main groove from the outer side of the vehicle when installed on the vehicle; an inner shoulder lug groove, the inner shoulder lug groove being arranged on the inner shoulder land portion and extending along the width direction of the tire; and an inner shoulder sipe pattern, one end of the inner shoulder sipe pattern being connected to the inner shoulder lug groove and the other end being connected to the 4th main groove.

[0022] Preferably, the inner shoulder lug groove has a curved portion at a position closer to the inside of the vehicle than the connection portion with the inner shoulder lug groove, and the extension direction of the portion of the inner shoulder lug groove closer to the inside of the vehicle than the curved portion is different from the extension direction of the inner shoulder sipe pattern.

[0023] The tire may include a recessed portion provided on the outer side in the tire width direction of the ground contact end of the inner shoulder land portion.

[0024] It may also include: an outer shoulder land portion, which is arranged on the outer side of the vehicle of the first main groove, i.e., the first main groove, from the outer side of the vehicle when installed on the vehicle; an outer shoulder lug groove, which is arranged on the outer shoulder land portion and extends along the width direction of the tire and terminates at one end in the outer shoulder land portion; and an outer shoulder sipe pattern, which is arranged on the outer shoulder land portion and extends along the width direction of the tire and terminates at one end in the outer shoulder land portion.

[0025] The outer shoulder lug grooves and the outer shoulder sipes may be alternately provided in the tire circumferential direction.

[0026] The tire may include a recessed portion provided on the outer side in the tire width direction of the ground contact end of the outer shoulder land portion.

[0027] It may also be that it includes: a third intermediate land portion, the third intermediate land portion being arranged between the second main groove, i.e., the second main groove, and the third main groove, i.e., the third main groove, from the outer side of the vehicle when installed on the vehicle; and a third sipe pattern, the third sipe pattern being arranged in the third intermediate land portion and extending along the tire circumferential direction, the relationship among the ratio SW1 / L1 of the extension length SW1 of the first sipe pattern in the tire width direction to the land portion width L1 of the first intermediate land portion, the ratio SW2 / L2 of the extension length SW2 of the second sipe pattern in the tire width direction to the land portion width L2 of the second intermediate land portion, and the ratio SW3 / L3 of the extension length SW3 of the third sipe pattern in the tire width direction to the land portion width L3 of the third intermediate land portion being the ratio SW1 / L1>the ratio SW2 / L2>the ratio SW3 / L3.

[0028] The device may include a mounting direction display unit that specifies mounting on the vehicle with the vehicle inner region when the device is mounted on the vehicle positioned inward in the vehicle width direction.

[0029] Effects of the Invention

[0030] The tire of the present invention has the effect of improving wet braking performance and wear resistance. BRIEF DESCRIPTION OF THE DRAWINGS

[0031] Figure 1 It is a meridian cross-sectional view of the tire according to this embodiment.

[0032] Figure 2 It is a plan view showing the tread surface of the tire according to the present embodiment.

[0033] Figure 3 It will Figure 2 FIG. 1 is an enlarged view of the first intermediate land portion in FIG.

[0034] Figure 4 It shows Figure 3 FIG. 1 is a diagram showing an example of the cross-sectional shape of the chamfered portion in FIG.

[0035] Figure 5 It will Figure 3 A diagram showing an enlarged portion of the diagram.

[0036] Figure 6 It will Figure 2 FIG2 is an enlarged view of the second middle land portion in FIG2.

[0037] Figure 7 It shows Figure 6 FIG. 1 is a diagram showing an example of the cross-sectional shape of the chamfered portion in FIG.

[0038] Figure 8 It shows Figure 6 FIG. 1 is a diagram showing an example of the cross-sectional shape of the chamfered portion in FIG.

[0039] Figure 9 It will Figure 6 A diagram showing an enlarged portion of the diagram.

[0040] Figure 10 It will Figure 2 The central land portion is enlarged and shown in the figure.

[0041] Figure 11 It shows Figure 10 FIG. 1 is a diagram showing an example of the cross-sectional shape of the chamfered portion in FIG.

[0042] Figure 12 It will Figure 10 A diagram showing an enlarged portion of the diagram.

[0043] Figure 13 It will Figure 2 FIG. 1 is an enlarged view of the inner shoulder land portion.

[0044] Figure 14 It will Figure 2 FIG. 1 is an enlarged view of the outer shoulder land portion in FIG. DETAILED DESCRIPTION

[0045] Hereinafter, embodiments of the present invention will be described in detail based on the accompanying drawings. In the following description of each embodiment, components that are identical or equivalent to other embodiments are marked with the same reference numerals, and their descriptions are simplified or omitted. The present invention is not limited to each embodiment. In addition, the constituent elements of each embodiment include elements that can be replaced and easily replaced by those skilled in the art, or substantially the same elements. In addition, the structures described below can be appropriately combined. In addition, the omission, replacement or change of the structure can be carried out within the scope of the gist of the invention.

[0046] (tire)

[0047] Figure 1 It is a meridian cross-sectional view of the tire 100 according to the present embodiment. Figure 2 is a top view showing the tread surface of tire 100 according to this embodiment. Tire 100 according to this embodiment is preferably a pneumatic tire. The gas filling tire 100 may be ordinary air or air with an adjusted oxygen partial pressure, or an inert gas such as nitrogen, argon, or helium.

[0048] In the following description, a tire meridian cross section refers to a cross section obtained by cutting the tire along a plane containing the tire's rotational axis (not shown). The tire radial direction refers to a direction perpendicular to the tire's rotational axis (not shown). The tire radial inside refers to the side radially toward the rotational axis, and the tire radial outside refers to the side radially away from the rotational axis. Furthermore, the tire circumferential direction refers to a direction circumferentially centered around the rotational axis. The tire width direction refers to a direction parallel to the rotational axis. The tire width inside refers to the side radially toward the tire equatorial plane (tire equatorial line) CL, and the tire width outside refers to the side radially away from the tire equatorial plane CL. The tire equatorial plane CL is a plane perpendicular to the rotational axis of the tire 100 and passing through the center of the tire width of the tire 100. The tire width is the width of each portion located on the tire's outside in the tire width direction, i.e., the distance between the portions farthest from the tire equatorial plane CL in the tire width direction. The tire equatorial line is a line located on the tire equatorial plane CL and along the tire circumference of the tire 100. In the present embodiment, the tire equator line is denoted by the same reference numeral “CL” as the tire equatorial plane.

[0049] exist Figure 1 and Figure 2 In the figure, T and T represent ground contact edges. These ground contact edges are the two outermost ends in the tire width direction where the tread surface 3 of the tread portion 2 of the tire 100 contacts the road surface when the tire 100 is assembled on a specified rim, filled to a specified internal pressure, and subjected to 70% of a specified load. The ground contact edges are continuous in the tire circumferential direction.

[0050] Here, the specified rim refers to the "Standard Rim" specified by JATMA, the "Design Rim" specified by TRA, or the "Measuring Rim" specified by ETRTO. Furthermore, the specified internal pressure refers to the maximum value stated in the "Maximum Air Pressure" specified by JATMA, the "Tire Load Limits at Variable Inflation Pressures" specified by TRA, or the "Inflation Pressures" specified by ETRTO. For example, the specified internal pressure is 250 kPa.

[0051] The tread surface 3 is provided with a plurality of circumferential main grooves 20 extending in the tire circumferential direction. These circumferential main grooves 20 include central main grooves 21a and 21b, which are closest to the tire equatorial plane CL, and shoulder main grooves 22b, which are located outwardly of the central main grooves 21a and 21b in the tire widthwise direction. Circumferential narrow grooves 23 are provided outwardly of the central main grooves 21a in the tire widthwise direction, extending in the tire circumferential direction. The central main groove 21a is sometimes referred to as the outer central main groove. The central main groove 21b is sometimes referred to as the inner central main groove. The shoulder main groove 22b is sometimes referred to as the inner shoulder main groove. These three circumferential main grooves 20 and the circumferential narrow grooves 23 define and form a plurality of land portions 31, 32a, 32b, and 33b.

[0052] The land portion 31 is provided between the central main groove 21a, which is the first main groove from the vehicle outer side (OUT side in the figure) when the tire is mounted on a vehicle, and the central main groove 21b, which is the second main groove. The land portion 32a is provided between the central main groove 21a, which is the first main groove from the vehicle outer side when the tire 100 is mounted on a vehicle, and the circumferential narrow groove 23. The land portion 32b is provided between the central main groove 21b, which is the second main groove from the vehicle outer side when the tire 100 is mounted on a vehicle, and the shoulder main groove 22b, which is the third main groove.

[0053] The land portion 31 is sometimes referred to as a central land portion or a third intermediate land portion. The land portion 32a provided on the vehicle outer side of the central land portion 31 is sometimes referred to as a first intermediate land portion, and the land portion 32b provided on the vehicle inner side of the central land portion 31 is sometimes referred to as a second intermediate land portion. The land portion 33a is sometimes referred to as an outer shoulder land portion, and the land portion 33b is sometimes referred to as an inner shoulder land portion.

[0054] The tire 100 has an annular structure centered on the tire rotation axis and includes a pair of bead cores 11 , 11 , a pair of bead fillers 12 , 12 , a carcass layer 13 , a belt layer 14 , a tread rubber 15 , a pair of sidewall rubbers 16 , 16 , and a pair of rim cushion rubbers 17 , 17 .

[0055] A pair of bead cores 11, 11 are formed by winding one or more bead wires made of steel in a toroidal shape multiple times, and are embedded in the bead portion 10 to form the core of the left and right bead portions 10. A pair of bead fillers 12, 12 are respectively arranged on the outer sides of the pair of bead cores 11, 11 in the tire radial direction to reinforce the bead portion 10.

[0056] The carcass layer 13 has a single-layer structure consisting of a single carcass ply or a multi-layer structure consisting of multiple carcass ply layers stacked together. It is arranged in a ring shape between the left and right bead cores 11, 11 to form the skeleton of the tire. In addition, the two ends of the carcass layer 13 are rolled back and fixed to the outside in the tire width direction in a manner to wrap the bead core 11 and the bead filler 12. In addition, the carcass ply of the carcass layer 13 is composed of multiple carcass cords made of steel or organic fiber materials (for example, aramid, nylon, polyester, rayon, etc.) covered with covering rubber and calendered, and has a cord angle of 80 degrees or more and 100 degrees or less. The cord angle is defined as the inclination angle of the longitudinal direction of the carcass cord relative to the circumferential direction of the tire.

[0057] exist Figure 1 In the structure of , the carcass layer 13 has a single-layer structure composed of a single carcass ply, and its turn-back portion 132 extends along the outer peripheral surface of the main body portion 131. The terminal end of the turn-back portion 132 is sandwiched between the belt layer 14 and the main body portion 131.

[0058] The belt layer 14 is formed by laminating a plurality of belt plies and is arranged around the outer periphery of the carcass layer 13. The belt layer 14 includes a pair of cross belts 141 and 142 and a belt cover 143. In this example, a plurality of belt covers 143 are provided.

[0059] The pair of cross belts 141 and 142 are constructed by covering multiple belt cords made of steel or organic fiber material with rubber and then calendering them. They have an absolute cord angle of 15 degrees or greater and 55 degrees or less. Furthermore, the pair of cross belts 141 and 142 have cord angles (defined as the inclination angle of the belt cord's longitudinal direction relative to the tire's circumferential direction) of different signs, and are layered so that the belt cords' longitudinal directions intersect with each other (a so-called cross-ply structure). Furthermore, the pair of cross belts 141 and 142 are layered and arranged radially outward of the carcass ply 13.

[0060] The belt cover 143 is constructed by covering belt cover cords made of steel or organic fiber material with covering rubber, and has an absolute cord angle of 0 degrees or more and 10 degrees or less. The belt cover 143 is, for example, a strip material formed by covering one or more belt cover cords with covering rubber, and this strip material is wound spirally multiple times around the outer circumference of the cross belts 141 and 142 in the tire circumferential direction. The belt cover 143 is positioned to cover the entire area of ​​the cross belts 141 and 142.

[0061] Tread rubber 15 is disposed on the tire radially outer periphery of carcass layer 13 and belt layer 14 to form tire tread portion 2. Shoulder portions 8 are located at both ends of tread portion 2 in the tire width direction. A pair of sidewall rubbers 16, 16 are disposed on the tire widthwise outer sides of carcass layer 13 to form left and right sidewall portions 6, respectively.

[0062] A pair of rim cushion rubbers 17, 17 extend from the tire radially inner side of the left and right bead cores 11, 11 and the turned portion 132 of the carcass layer 13 to the tire widthwise outer side, forming the rim fitting surface of the bead portion 10. The rim fitting surface is the contact surface of the bead portion 10 with the rim flange (not shown).

[0063] The inner liner 18 is an air permeation prevention layer disposed on the inner surface of the tire and covering the carcass layer 13. It suppresses oxidation caused by exposure of the carcass layer 13 and prevents leakage of the air filling the tire. The inner liner 18 is composed of, for example, a rubber composition mainly composed of butyl rubber, a thermoplastic resin, or a thermoplastic elastomer composition obtained by mixing an elastomer component with a thermoplastic resin.

[0064] The internal structure of the tire 100 described above is a representative example of the tire 100 , and the internal structure is not limited thereto.

[0065] (Tread)

[0066] The following describes the tread portion 2 in detail. In the following description, the groove width is measured as the distance between opposing groove walls at the groove opening, in an unloaded state, with the tire mounted on a specified rim and filled to a specified internal pressure. In configurations where the groove opening has a notch or chamfer, the groove width is measured using the intersection of an extension line of the tread and an extension line of the groove wall in a cross-sectional view parallel to both the groove width and groove depth directions as the measurement point. The groove depth is measured as the distance from the tread to the groove bottom, in an unloaded state, with the tire mounted on a specified rim and filled to a specified internal pressure. Furthermore, in configurations where the groove bottom has localized raised bottoms or concave-convex portions, these are excluded from the groove depth measurement.

[0067] like Figure 2As shown, the tread portion 2 has a plurality of circumferential main grooves 20 extending along the tire circumference. Two circumferential main grooves 20 are arranged on the outer side in the tire width direction, with the tire equatorial plane CL as the boundary. Furthermore, on the vehicle's outer side, the circumferential main grooves 20 closer to the tire equatorial plane CL are referred to as outer central main grooves (also referred to as central main grooves) 21a. On the vehicle's inner side, the circumferential main grooves 20 closer to the tire equatorial plane CL are referred to as inner central main grooves (also referred to as central main grooves) 21b, and the circumferential main grooves 20 on the outer side of the inner central main grooves 21b in the tire width direction are referred to as inner shoulder main grooves (also referred to as shoulder main grooves) 22b.

[0068] Main grooves are grooves that have the duty of displaying wear indicators as specified by JATMA and have a groove width of 5.0 mm to 12 mm and a groove depth of 5.0 mm or more. Furthermore, the lug grooves, described later, extend in the tire's width direction and have a groove width of 2.0 mm to 4.0 mm and a groove depth of 3.0 mm or more. They open when the tire is in contact with the ground and function as grooves. The sipes, described later, are cuts formed in the tread surface and have a groove width of 1.0 mm to 2.0 mm and a groove depth of 3.0 mm to 5.0 mm. The sipes close when the tire is in contact with the ground.

[0069] A continuous chamfer along the tire circumferential direction may be provided at both ends of each land portion in the tire width direction, i.e., at the boundary between the land portion and the main groove 20. When such a chamfer is provided, the land portion width, groove width, groove length, etc. are measured assuming the shape of the land portion without the chamfer.

[0070] (1st middle land portion)

[0071] Figure 3 It will Figure 2 FIG. 3 is an enlarged view of the first intermediate land portion 32a. Figure 3 As shown, a sipe 41 (first sipe) is provided in the first intermediate land portion 32a. A plurality of sipes 41 are arranged in the tire circumferential direction. The sipes 41 extend in the tire width direction and in the tire circumferential direction. The sipes 41 penetrate the first intermediate land portion 32a. That is, one end of the sipe 41 opens to the central main groove 21a, and the other end of the sipe 41 terminates in the first intermediate land portion 32a. In addition, Figure 3 The one-dot chain line in is the groove center line of the sipe 41 .

[0072] The ratio SW1 / L1 (the length SW1 extending in the tire width direction of the sipe 41) to the length of the first intermediate land portion 32a in the tire width direction, i.e., the land portion width L1, is preferably 0.7 or greater and 0.9 or less. When the ratio SW1 / L1 is within this range, wet braking performance and wear resistance can be improved. Furthermore, the ratio L41 / SW1 (the length L41 extending in the tire circumferential direction of the sipe 41) to the length SW1 extending in the tire width direction of the sipe 41 is preferably 0.4 or greater and 0.8 or less. When the ratio L41 / SW1 is within this range, wet braking performance and wear resistance can be improved.

[0073] The sipe 41 is curved in the first middle land portion 32a. The sipe 41 includes a first inclined portion 41a inclined toward one side relative to the tire circumferential direction and a second inclined portion 41b inclined toward the other side relative to the tire circumferential direction. The first inclined portion 41a is inclined toward the tire circumferential direction. Figure 3 The lower side of the tire is facing the upper side, Figure 3 The second inclined portion 41b is inclined toward the left side (IN side, i.e., the inner side of the vehicle). Figure 3 The lower side of the tire is facing the upper side, Figure 3 The first inclined portion 41a and the second inclined portion 41b are inclined toward the right side (OUT side, i.e., the vehicle outer side) of the tire. That is, the first inclined portion 41a and the second inclined portion 41b are inclined in opposite directions relative to the tire circumferential direction. The inclination angle θa of the first inclined portion 41a relative to the tire circumferential direction is preferably greater than or equal to 30 degrees and less than or equal to 80 degrees. The inclination angle θb of the second inclined portion 41b relative to the tire circumferential direction is preferably greater than or equal to 30 degrees and less than or equal to 80 degrees.

[0074] The first inclined portion 41a has chamfered portions 81 (first chamfered portions). Chamfered portions 81 are provided on both sides of the first inclined portion 41a in the groove width direction. The ratio MW1 / SW1 of the extending length MW1 of the chamfered portion 81 in the tire width direction to the extending length SW1 of the first intermediate land portion 32a in the tire width direction is preferably 0.2 or greater and 0.4 or less. When the ratio MW1 / SW1 falls within this range, wet braking performance and wear resistance can be improved.

[0075] (Cross-sectional shape of the first chamfered portion)

[0076] Figure 4 It shows Figure 3 FIG. 1 is a diagram showing an example of the cross-sectional shape of the chamfered portion 81 in FIG. Figure 4 It shows Figure 3 The cross section of the AA section in FIG. Figure 4 As shown, the first inclined portion 41a of the sipe 41 has a main body 71 extending from the tread surface of the first intermediate land portion 32a in the tire radial direction, i.e., the groove depth direction, and a chamfered portion 81 provided at the opening of the main body 71 opening to the first intermediate land portion 32a.

[0077] exist Figure 4 In the embodiment, when the depth of the main body 71 including the depth of the chamfered portion 81 is represented by Ds, the depth of the chamfered portion 81 (the depth of the deepest portion) is represented by Dm, and the groove depth of the circumferential main groove 20 is represented by D, the depth relationship is D>Ds>Dm. With such a depth relationship, the wear resistance can be improved while maintaining the block rigidity, and the wet braking performance can be improved.

[0078] The depth of the circumferential main groove 20 is, for example, 4 mm to 8 mm inclusive. The depth Ds of the main body 71, including the depth of the chamfered portion 81, is, for example, 3 mm to 6 mm inclusive. The depth Dm of the chamfered portion 81 (the depth of the deepest portion) is, for example, 1 mm to 2 mm inclusive.

[0079] The width ML of the tread of the first intermediate land portion 32a, perpendicular to the extension direction of the main body portion 71, including the chamfered portion 81, is preferably 2.0 mm to 5.0 mm. The width of the chamfered portion 81 is preferably 1.0 mm to 3.0 mm. The width ML is greater than the depth Dm of the chamfered portion 81, and ML>Dm. Furthermore, the width ML of the chamfered portion 81 decreases toward the deepest portion Md. This depth relationship maintains pad rigidity, improving wet braking performance and wear resistance.

[0080] Figure 5 It will Figure 3 A part of the diagram is enlarged. Figure 5 As shown, the inflection point of the sipe 41 is defined as P1. The chamfered portion 81 terminates between the opening of the first inclined portion 41a of the sipe 41 into the main groove 21a and the inflection point P1. The ratio MW1 / WP1 (the length MW1 extending in the tire width direction of the chamfered portion 81 relative to the length WP1 from the opening of the first inclined portion 41a into the main groove 21a to the inflection point P1) is preferably 0.5 or greater and 0.9 or less. A value within this range of the ratio MW1 / WP1 improves wet braking performance and wear resistance.

[0081] The ratio LM1 / MW1 of the extending length LM1 of the chamfered portion 81 in the tire circumferential direction to the extending length MW1 of the chamfered portion 81 in the tire width direction is preferably 0.8 or more and 1.4 or less. When the ratio LM1 / MW1 is within this range, wet braking performance and wear resistance can be improved.

[0082] The angle θ1 formed between the center line S11 of the first inclined portion 41a and the center line S12 of the groove width of the second inclined portion 41b is preferably greater than 60 degrees and less than 160 degrees. If the angle θ1, the curvature angle of the sipe 41, is within this range, the pad rigidity can be maintained, and wet braking performance and wear resistance can be improved.

[0083] (Circumferential groove)

[0084] Return to Figure 3 A chamfered portion 23a is provided on the edge of the first intermediate land portion 32a on the circumferential groove 23 side. The chamfered portion 23a is provided on the groove wall surface of the circumferential groove 23 on the first intermediate land portion 32a side. The chamfered portion 23a is composed of a long portion 23L and a short portion 23S, each having different lengths in the tire circumferential direction. The chamfered portion 23a extends circumferentially in the tire, with the length, or chamfer width, varying in the tire width direction. Specifically, the circumferential groove 23 includes a serrated chamfered portion 23a, or a zigzag chamfered portion, provided on the groove wall surface on the first intermediate land portion 32a side. The chamfered portion 23a extends circumferentially in the tire, with its position varying in the tire width direction. The ratio (W23a / L1) of the maximum width W23a of the chamfered portion 23a in the tire width direction to the land portion width L1 of the first intermediate land portion 32a is preferably 0.1 or greater and 0.3 or less. When the ratio W23a / L1 is within this range, wet braking performance and anti-wear performance can be improved.

[0085] (Relationship between the sipe pattern and the chamfered portion of the first intermediate land portion)

[0086] Refer again Figure 5 . Assume that the center line S12 of the second inclined portion 41b is extended to obtain an extended line S121. With the terminal portion 411 of the second inclined portion 41b of the first sipe 41 as a reference, a chamfered portion 23a is provided within the range of the angle θ11 of the extended line S121. More specifically, a maximum width position 23M of the chamfered portion 23a is provided within the range of the angle θ11 of the extended line S121. The angle θ11 is within ±10 degrees with respect to the extended line S121. If such a positional relationship is established, drainage performance can be ensured, wet braking performance is improved, and wear resistance can be improved.

[0087] When the second inclined portion 41 b is curved, an extension line of an imaginary line connecting the bending point P1 and the terminal end 411 of the second inclined portion 41 b with a straight line is referred to as an extension line S121 .

[0088] (Second middle land portion)

[0089] Figure 6 It will Figure 2 FIG2 is an enlarged view of the second intermediate land portion 32b. Figure 6As shown, a sipe 42 (second sipe) is provided in the second middle land portion 32b. A plurality of sipes 42 are arranged in the tire circumferential direction. The sipe 42 is curved in the second middle land portion 32b. When the opening 40 of the sipe 42 that opens to the shoulder main groove 22b is used as a reference, the sipe 42 extends from the position of the opening 40 toward the shoulder main groove 22b. Figure 6 The sipe 42 is inclined to the lower right of the tire. Therefore, the sipe 42 extends in the tire width direction and in the tire circumferential direction. The sipe 42 does not penetrate the second intermediate land portion 32b. That is, one end of the sipe 42 opens to the shoulder main groove 22b, and the other end of the sipe 42 ends in the second intermediate land portion 32b. The sipe 42 does not penetrate the second intermediate land portion 32b. In addition, Figure 6 The one-dot chain line in is the groove center line of the sipe 42 .

[0090] The ratio SW2 / L2 (the tire widthwise extension length SW2 of the sipe 42) to the tire widthwise length of the second intermediate land portion 32b, i.e., the land portion width L2, is preferably 0.6 or greater and 0.8 or less. When the ratio SW2 / L2 falls within this range, wet braking performance and wear resistance can be improved.

[0091] The ratio L42 / SW2 of the sipe 42 extending in the tire circumferential direction L42 to the sipe 42 extending in the tire width direction SW2 is preferably 1.0 or more and 1.5 or less. When the ratio L42 / SW2 is within this range, wet braking performance and wear resistance can be improved.

[0092] The sipe 42 has a chamfered portion 82 (second chamfered portion). The chamfered portion 82 is provided on one side of the sipe 42 in the groove width direction. The ratio MW2 / SW2 (the length MW2 extending in the tire width direction of the chamfered portion 82 relative to the length SW2 extending in the tire width direction of the sipe 42) is preferably 0.4 or greater and 0.6 or less. When the ratio MW2 / SW2 falls within this range, wet braking performance and wear resistance can be improved.

[0093] (Cross-sectional shape of the second chamfered portion)

[0094] Figure 7 and Figure 8 It shows Figure 6 FIG. 2 is a diagram showing an example of the cross-sectional shape of the chamfered portion 82 in FIG. Figure 7 It shows Figure 6 FIG. 1 is a diagram showing a cross section of the sipe 42 at a position close to the opening 40 , that is, at the B1 - B1 portion. Figure 8 It shows Figure 6 The cross section of the B2-B2 portion in FIG. Figure 7 and Figure 8As shown, the sipe 42 includes a main body portion 72 extending from the tread surface of the second intermediate land portion 32b in the tire radial direction, i.e., the groove depth direction; and a chamfered portion 82 provided at an opening of the main body portion 72 that opens to the second intermediate land portion 32b.

[0095] exist Figure 7 、 Figure 8 In the embodiment, when the depth of the main body 72 including the depth of the chamfered portion 82 is Ds, the depth of the chamfered portion 82 (the deepest portion) is Dm, and the groove depth of the circumferential main groove 20 is D, the depth relationship is D>Ds>Dm. With such a depth relationship, the block rigidity can be maintained while the wear resistance is improved, and the wet braking performance can be improved.

[0096] The depth Ds of the main body 72 including the depth of the chamfered portion 82 is, for example, 3 mm to 6 mm inclusive. The depth Dm of the chamfered portion 82 (depth of the deepest portion) is, for example, 1 mm to 2 mm inclusive.

[0097] exist Figure 7 In the figure, the width of the tread of the second intermediate land portion 32b in the direction perpendicular to the extending direction of the main body portion 72, that is, the width including the chamfered portion 82, is ML1. Figure 8 In the embodiment, the width of the tread surface of the second intermediate land portion 32b in a direction perpendicular to the extending direction of the main body portion 72, that is, the width including the chamfered portion 82, is denoted as ML2. The width ML1 of the sipe 42 near the opening 40 is greater than the width ML2 of the sipe 42 near the terminal end 40t. When the widths ML1 and ML2, including the chamfered portion 82, have such a relationship, drainage performance can be maintained, and wet braking performance is improved.

[0098] Figure 9 It will Figure 6 A portion of the diagram is enlarged. Figure 9 As shown, the sipe 42 includes a straight portion 421 connected to the opening 40 and a straight portion 422 connected to the terminal portion 40t. The angle θ2 formed by the straight line L11 (extending the groove centerline of the straight portion 421) and the straight line L21 (extending the groove centerline of the straight portion 422) (i.e., the angle formed between the straight portions) is preferably 60 degrees or more and 160 degrees or less. When the angle θ2, the curvature angle of the sipe 42, falls within this range, wet braking performance and wear resistance can be improved.

[0099] Here, the length of the groove center of the sipe 42 is represented by L420, and the length of the portion of the sipe 42 excluding the chamfered portion 82 is represented by L421. The ratio L420 / L421 of the length L421 to the length L420 is preferably 0.1 or greater and 0.5 or less. When the ratio L420 / L421 falls within this range, wet braking performance and wear resistance can be improved.

[0100] The width of the chamfered portion 82 at the opening 40 of the sipe 42 is denoted by W421, and the width of the terminal end of the chamfered portion 82 is denoted by W422. The ratio W421 / W422 of width W421 to width W422 is preferably 0.3 or greater and 0.8 or less. When the ratio W421 / W422 falls within this range, drainage performance is maintained, and wet braking performance is improved.

[0101] At the opening 40 of the sipe 42, the angle θ40 of the straight portion 421 of the sipe 42 relative to the tire circumferential direction is preferably an acute angle of 30 degrees to 80 degrees. When the angle θ40 is within this range, wet braking performance and wear resistance can be improved.

[0102] (Central Land Department)

[0103] Figure 10 It will Figure 2 The central land portion 31 in FIG is enlarged and shown. Figure 10 As shown, a sipe 43 (third sipe) is provided in the central land portion 31. A plurality of sipes 43 are arranged in the tire circumferential direction. The sipe 43 is curved in the central land portion 31. When the opening 40c of the sipe 43 that opens to the central main groove 21b is used as a reference, the sipe 43 extends from the position of the opening 40c toward the central main groove 21b. Figure 10 The sipe 43 is inclined to the lower right in the tire. Therefore, the sipe 43 extends in the tire width direction and in the tire circumferential direction. The sipe 43 does not penetrate the central land portion 31. That is, one end of the sipe 43 opens to the central main groove 21b, and the other end of the sipe 43 ends at the terminal portion 40e in the central land portion 31. The sipe 43 does not penetrate the central land portion 31. In addition, Figure 10 The one-dot chain line in is the groove center line of the sipe 43 .

[0104] The ratio SW3 / L3 of the tire widthwise extension length SW3 of the sipe 43 to the tire widthwise length L3 of the center land portion 31 is preferably 0.5 or greater and 0.7 or less. When the ratio SW3 / L3 is within this range, wet braking performance and wear resistance can be improved.

[0105] The ratio L43 / SW3 of the sipe 43's circumferential extension length L43 to the sipe's widthwise extension length SW3 is preferably 1.0 or greater and 1.5 or less. When the ratio L43 / SW3 is within this range, wet braking performance and wear resistance can be improved.

[0106] The sipe 43 has chamfered portions 83a and 83b (third chamfered portions). The chamfered portions 83a and 83b are provided on both sides of the sipe 43 in the groove width direction. In this example, the chamfered portions 83a and 83b are provided along the entire length of the sipe 43.

[0107] (Cross-sectional shape of the third chamfered portion)

[0108] Figure 11 It shows Figure 10 1 and 2 are diagrams showing examples of cross-sectional shapes of chamfered portions 83a and 83b in FIG. Figure 11 It shows Figure 10 The cross section of the CC section is shown in FIG. Figure 11 As shown, the sipe 43 has: a main body portion 73, which extends from the tread surface of the central land portion 31 in the tire radial direction, i.e., the groove depth direction; and chamfered portions 83a, 83b, which are arranged on both sides of the opening of the main body portion 73 that opens to the central land portion 31.

[0109] exist Figure 11 In the embodiment, when the depth of the main body 73 including the depth of the chamfered portions 83a and 83b is represented by Ds, the depth of the chamfered portions 83a and 83b (the depth of the deepest portion) is represented by Dm, and the groove depth of the circumferential main groove 20 is represented by D, the depth relationship is D>Ds>Dm. With such a depth relationship, the wear resistance can be improved while maintaining the block rigidity, and the wet braking performance can be improved.

[0110] The depth Ds of the main body 73 including the depths of the chamfered portions 83a and 83b is, for example, 3 mm to 6 mm. The depth Dm of the chamfered portions 83a and 83b (the deepest portion) is, for example, 1 mm to 2 mm.

[0111] The width of the tread of the center land portion 31 in a direction perpendicular to the extension direction of the main body portion 73, that is, the width MLa including the chamfered portions 83a and 83b, is preferably 4.0 mm to 10.0 mm. The width MLa is greater than the depth Dm of the chamfered portions 83a and 83b. Furthermore, the width MLa of the chamfered portion 81 decreases toward the deepest portion Md. This depth relationship maintains pad rigidity, improving wet braking performance and wear resistance.

[0112] Figure 12It will Figure 10 A portion of the diagram is enlarged. Figure 12 As shown, the sipe 43 includes a straight portion 431 connected to the opening 40c and a straight portion 432 connected to the terminal 40e. The angle θ3 formed by a straight line L31 extending the groove centerline of the straight portion 431 and a straight line L32 extending the groove centerline of the straight portion 432 is preferably 60 degrees or more and 160 degrees or less. When the angle θ3, the curvature angle of the sipe 43, falls within this range, wet braking performance and wear resistance can be improved.

[0113] At the opening 40c of the sipe 42, the angle θ43 of the straight portion 431 of the sipe 43 with respect to the tire circumferential direction is preferably 30 degrees or more and 80 degrees or less. When the angle θ43 is within this range, wet braking performance and wear resistance can be improved.

[0114] (Inner shoulder land portion)

[0115] Figure 13 It will Figure 2 FIG. 3 is an enlarged view of the inner shoulder land portion 33b. Figure 13 As shown, the inner shoulder land portion 33b has shoulder lug grooves 45. The shoulder lug grooves 45 extend in the tire circumferential direction and the tire width direction. The shoulder lug grooves 45 include lug grooves 451 and sipes 452. The lug grooves 451 and sipes 452 extend in different directions.

[0116] One end of the lug groove 451 is connected to the sipe 452. The other end of the lug groove 451 extends beyond the contact end T. One end of the sipe 452 is connected to the lug groove 451. The other end of the sipe 452 is connected to the shoulder main groove 22b. In other words, the lug groove 451 is connected to the shoulder main groove 22b via the sipe 452. The ratio W452 / W33 of the tire widthwise extension length W452 of the sipe 452 to the tire widthwise distance W33 from the shoulder main groove 22b to the contact end T is preferably 0.3 or greater and 0.8 or less. If the ratio W452 / W33 is within this range, wet braking performance and wear resistance can be improved.

[0117] Furthermore, the inner shoulder land portion 33b has a plurality of recessed portions 51. The recessed portions 51 are recessed from the outer surface of the tire 100 toward the inner cavity. The recessed portions 51 are provided in the outer end region of the inner shoulder land portion 33b in the tire width direction. The recessed portions 51 are provided outboard of the contact patch T. The provision of the recessed portions 51 can suppress an increase in the rigidity of the outer surface of the tire 100.

[0118] (Outer shoulder land portion)

[0119] Figure 14 It will Figure 2 FIG. 3 is an enlarged view of the outer shoulder land portion 33a. Figure 14 As shown, the outer shoulder land portion 33a has a shoulder lug groove 46 and a shoulder sipe 47. The shoulder lug groove 46 extends in the tire width direction and the tire circumferential direction. The shoulder sipe 47 extends in the tire width direction and the tire circumferential direction. The shoulder lug groove 46 and the shoulder sipe 47 are arranged alternately in the tire circumferential direction. One end of the shoulder lug groove 46 terminates in the outer shoulder land portion 33a, and the other end extends beyond the ground contact end T to the outside of the ground contact end T. The lug groove 46 is not connected to the circumferential fine groove 23. One end of the shoulder sipe 47 terminates in the outer shoulder land portion 33a, and the other end extends beyond the ground contact end T to the outside of the ground contact end T. The shoulder sipe 47 is not connected to the circumferential fine groove 23.

[0120] The circumferential narrow groove 23 extends in the tire circumferential direction. The groove width of the circumferential narrow groove 23, excluding the chamfered portion 23a, is preferably 1.0 mm to 4.0 mm. When the groove width of the circumferential narrow groove 23 falls within this range, wet braking performance and wear resistance can be improved.

[0121] Here, the length of one pitch of the shoulder sipes 47 is represented by L47, and the circumferential length of one pitch of the chamfered portion 23a is represented by L23a. The ratio of length L23a to length L47 (L23a / L47) is preferably 0.95 or greater and 1.05 or less. When the ratio L23a / L47 falls within this range, wet braking performance and wear resistance can be improved.

[0122] Furthermore, the outer shoulder land portion 33a has a plurality of recessed portions 51. The recessed portions 51 are recessed from the outer surface of the tire 100 toward the inner cavity. The recessed portions 51 are provided in the outer end region of the outer shoulder land portion 33a in the tire width direction. The recessed portions 51 are provided outboard of the contact patch T. The provision of the recessed portions 51 can suppress an increase in the rigidity of the outer surface of the tire 100.

[0123] (Land width, sipe extension length, sipe bending angle)

[0124] Return to Figure 2The land width L1 of the first middle land portion 32a, the land width L2 of the second middle land portion 32b, and the land width L3 of the central land portion 31 are preferably in the relationship of L1 < L2 < L3. Furthermore, the tire widthwise extension length SW1 of the sipes 41 of the first middle land portion 32a, the tire widthwise extension length SW2 of the sipes 42 of the second middle land portion 32b, and the tire widthwise extension length SW3 of the sipes 43 of the central land portion 31 are preferably in the relationship of SW1 > SW2 > SW3. Furthermore, the ratio SW1 / L1 > the ratio SW2 / L2 > the ratio SW3 / L3 are preferably achieved. This size relationship allows for uniform rigidity of each land portion, improving wet braking performance and wear resistance.

[0125] As described above, when the land portion widths L1, L2, and L3 are in the relationship L1 < L2 < L3, the bending angles (angle θ1) of the sipes 41 of the first intermediate land portion 32a having the narrowest land portion width L1, the bending angles (angle θ2) of the sipes 42 of the second intermediate land portion 32b having the land portion width L2, and the bending angles (angle θ3) of the sipes 43 of the central land portion 31 having the widest land portion width L3 preferably maintain the relationship θ1 < θ2 < θ3. In other words, the narrower the land portion width, the smaller the bending angle (i.e., closer to 90 degrees), while the wider the land portion width, the larger the bending angle (i.e., closer to 180 degrees). This relationship among the three bending angles allows for uniform rigidity of the land portions, improving wet braking performance and wear resistance.

[0126] (Installation direction relative to the vehicle)

[0127] The tire 100 of this embodiment is specified with respect to the vehicle's installation direction. That is, when the tire 100 of this embodiment is installed on a vehicle, its orientation relative to the outside and inside of the vehicle in the tire width direction is specified. Although the designation of the orientation is not explicitly shown in the figure, it is indicated, for example, by an installation direction display portion provided on the sidewall portion 6. The installation direction display portion is a display portion that specifies that the area inside the vehicle when installed on the vehicle is to be installed on the vehicle as the inside in the vehicle width direction. The installation direction display portion is composed of, for example, marks and projections attached to the sidewall portion of the tire. For example, ECER30 (Economic Commission for Europe Regulation Article 30) imposes an obligation to provide an installation direction display portion on the sidewall portion that becomes the outside in the vehicle width direction when installed on the vehicle. Since the orientation relative to the outside and inside of the vehicle is specified by the installation direction display portion, when installed on the vehicle, the side facing the outside of the vehicle becomes the outside of the vehicle, and the side facing the inside of the vehicle becomes the inside of the vehicle. In addition, the designation of the outside and inside of the vehicle is not limited to the case of installation on the vehicle. For example, when the rim is assembled, the orientation of the rim relative to the vehicle's outside and inside in the tire width direction is determined. Therefore, when the rim is assembled, the orientation of the tire 100 relative to the vehicle's outside and inside in the tire width direction is specified.

[0128] (Variation)

[0129] The above description describes a case where three circumferential main grooves 20 and three circumferential narrow grooves 23 are provided in the tread portion of the tire 100. A circumferential main groove may be provided in place of the circumferential narrow grooves 23. In this case, the groove depth of the circumferential narrow grooves 23 is approximately the same as that of the circumferential main grooves 20, and four circumferential main grooves 20 are provided in the tread portion.

[0130] (Example)

[0131] Tables 1 to 7 show the results of performance tests on tires according to this embodiment. These tests evaluated various test tires for wet braking performance and wear resistance. 155 / 65R14 test tires were assembled onto wheels with 14×4.5J rims and installed on a FF light vehicle (700cc total displacement) at an air pressure of 240 kPa.

[0132] For wet braking performance, the braking distance of the test vehicles was measured on a wet road surface with a water depth of 1mm at a speed of 100 km / h. The reciprocal of the measured value was used, with a larger index indicating superior wet performance. For wear resistance, the test vehicles were driven on a dry test course. The distance traveled until the tread surface was completely worn away, i.e., until the wear indicators provided in the circumferential main grooves 20 became visible, was measured. The measured distance was then indexed for evaluation. A larger index value indicates superior wear resistance.

[0133] The tire of Conventional Example 1 in Table 1 has sipes with curved portions in the land portion and no circumferential narrow grooves. The tire of Comparative Example 1 in Table 1 has sipes with curved portions in the land portion and no zigzag chamfers in the circumferential narrow grooves. The tire of Comparative Example 2 in Table 3 has sipes with curved portions in the land portion, zigzag chamfers in the circumferential narrow grooves, and no maximum width position of the zigzag chamfers on the extension line of the second inclined portion.

[0134] The tires of Examples 1 to 52 shown in Tables 1 to 7 are tires in which the first sipes 41 provided in the first intermediate land portion 32a are curved. The first sipes 41 have a first inclined portion opening into the central main groove 21a and a second inclined portion terminating in the first intermediate land portion 32a. The tires include a circumferential narrow groove 23 having a zigzag chamfered portion, and the zigzag chamfered portion is provided on an extension of the centerline of the second inclined portion. As shown in Tables 1 to 7, the tires of Examples 1 to 52 achieved excellent results in terms of wet braking performance and wear resistance.

[0135] [Table 1]

[0136]

[0137] [Table 2]

[0138]

[0139] [Table 3]

[0140]

[0141] [Table 4]

[0142]

[0143] [Table 5]

[0144]

[0145] [Table 6]

[0146]

[0147] [Table 7]

[0148]

[0149] Description of Reference Numerals

[0150] 2 Tread

[0151] 3 Tread surface

[0152] 6 Sidewall

[0153] 8. Shoulder

[0154] 10 Bead

[0155] 11 Bead core

[0156] 12 Bead filler

[0157] 13 carcass layer

[0158] 14 belt layer

[0159] 15 tread rubber

[0160] 16 Sidewall rubber

[0161] 17 Rim cushion rubber

[0162] 18 lining layer

[0163] 20 Circumferential main groove

[0164] 21a Outer central main groove

[0165] 21b inner central main groove

[0166] 22b Inner shoulder main groove

[0167] 23 Circumferential groove

[0168] 31 Central Land Department

[0169] 32a 1st middle land portion

[0170] 32b 2nd middle land part

[0171] 33a Outer shoulder land portion

[0172] 33b Inner shoulder land

[0173] 41 1st sipe

[0174] 41a First inclined portion

[0175] 41b second inclined portion

[0176] 42 2nd sipe

[0177] 43 3rd sipe pattern

[0178] 45, 46 shoulder transverse grooves

[0179] 47 Shoulder Sipes

[0180] 51 Depression

[0181] 81 1st chamfer

[0182] 82 2nd chamfer

[0183] 83a, 83b third chamfered portion

[0184] 100 tires

Claims

1. A tire comprising: at least three main grooves, wherein the at least three main grooves are provided in the tread portion; a circumferential narrow groove provided on the vehicle outer side of the first main groove (i.e., the first main groove) when the tire is installed on the vehicle and extending in the tire circumferential direction; and a first sipe provided in a first intermediate land portion between the first main groove and the circumferential narrow groove, The circumferential narrow groove has a sawtooth chamfered portion provided on the side surface on the first intermediate land portion side. The first sipe is bent at a curved portion provided between the first main groove and the circumferential narrow groove. The first sipe includes a first inclined portion provided on one side of the curved portion in the tire width direction, inclined with respect to the tire circumferential direction, and opening toward the first main groove; and a second inclined portion provided on the other side of the curved portion in the tire width direction and inclined toward the opposite side of the first inclined portion with respect to the tire circumferential direction and terminating between the curved portion and the circumferential narrow groove, The serrated chamfered portion is provided on an extension line of a center line of the second inclined portion.

2. The tire according to claim 1, The maximum width position of the serrated chamfered portion is set within a range of ±10 degrees from an extension line of the second inclined portion with the terminal end position of the second inclined portion as a reference.

3. The tire according to claim 1 or 2, A ratio SW1 / L1 of an extension length SW1 of the first sipe in the tire width direction to a land portion width L1 of the first middle land portion is 0.7 or more and 0.9 or less.

4. The tire according to any one of claims 1 to 3, One end of the first inclined portion opens to the first main groove. The first inclined portion has a first chamfered portion provided at a portion of the side surface on the way from the one end to the bent portion. A ratio MW1 / SW1 of an extension length MW1 of the first chamfered portion in the tire width direction to an extension length SW1 of the first sipe in the tire width direction is 0.2 or more and 0.4 or less.

5. The tire according to any one of claims 1 to 4, The tire comprises: a second intermediate land portion provided between the second main groove and the third main groove from the vehicle outer side when the tire is installed on the vehicle; and a second sipe provided in the second intermediate land portion and extending in the tire circumferential direction. One end of the second sipe opens to the third main groove, and the other end of the second sipe terminates in the second middle land portion. The second sipe is curved on the way from the one end to the other end, The second sipe has a second chamfered portion provided at a portion of a side surface midway from the one end to the other end.

6. The tire according to claim 5, A ratio SW2 / L2 of an extension length SW2 of the second sipe in the tire width direction to a land portion width L2 of the second middle land portion is 0.6 or more and 0.8 or less.

7. The tire according to claim 5 or 6, A ratio MW2 / SW2 of an extension length MW2 of the second chamfered portion in the tire width direction to an extension length SW2 of the second sipe in the tire width direction is 0.4 or more and 0.6 or less.

8. The tire according to any one of claims 1 to 7, The tire comprises: a third intermediate land portion provided between the first main groove and the second main groove from the vehicle outer side when the tire is installed on the vehicle; and a third sipe provided in the third intermediate land portion and extending in the tire circumferential direction. One end of the third sipe opens to the second main groove, and the other end of the third sipe terminates in the third middle land portion. The third sipe is curved on the way from the one end to the other end. The third sipe has second chamfered portions on both side surfaces on the way from the one end to the other end.

9. The tire according to claim 8, A ratio SW3 / L3 of an extension length SW3 of the third sipe in the tire width direction to a land portion width L3 of the third intermediate land portion is greater than or equal to 0.5 and less than or equal to 0.

7.

10. The tire according to any one of claims 1 to 9, The tire comprises: An inner shoulder land portion, the inner shoulder land portion being arranged on the vehicle inner side of the 4th main groove from the outer side of the vehicle when installed on the vehicle; an inner shoulder lug groove, the inner shoulder lug groove being arranged on the inner shoulder land portion and extending in the tire width direction; and an inner shoulder sipe pattern, one end of the inner shoulder sipe pattern being connected to the inner shoulder lug groove and the other end being connected to the 4th main groove.

11. The tire according to claim 10, The inner shoulder lug groove has a curved portion at a position closer to the vehicle inner side than the connection portion with the inner shoulder lug groove, and the extension direction of the portion of the inner shoulder lug groove closer to the vehicle inner side than the curved portion is different from the extension direction of the inner shoulder sipe pattern.

12. The tire according to claim 10 or 11, The tire includes a recessed portion provided at a tire width direction outer side of a ground contact end of the inner shoulder land portion.

13. The tire according to any one of claims 1 to 12, The tire comprises: An outer shoulder land portion, the outer shoulder land portion being arranged on the vehicle outer side of the first main groove, i.e., the first main groove, from the outer side of the vehicle when installed on the vehicle; an outer shoulder lug groove, the outer shoulder lug groove being arranged on the outer shoulder land portion and extending in the tire width direction and terminating at one end in the outer shoulder land portion; and an outer shoulder sipe pattern, the outer shoulder sipe pattern being arranged on the outer shoulder land portion and extending in the tire width direction and terminating at one end in the outer shoulder land portion.

14. The tire according to claim 13, The outer shoulder lug grooves and the outer shoulder sipes are alternately arranged in the tire circumferential direction.

15. The tire according to claim 13 or 14, The tire includes a recessed portion provided at the tire width direction outer side of the ground contact end of the outer shoulder land portion.

16. The tire according to claim 5, The tire comprises: a third intermediate land portion provided between the second main groove and the third main groove from the vehicle outer side when the tire is installed on the vehicle; and a third sipe provided in the third intermediate land portion and extending in the tire circumferential direction. The relationship among the ratio SW1 / L1 of the extension length SW1 of the first sipe pattern in the tire width direction to the land portion width L1 of the first intermediate land portion, the ratio SW2 / L2 of the extension length SW2 of the second sipe pattern in the tire width direction to the land portion width L2 of the second intermediate land portion, and the ratio SW3 / L3 of the extension length SW3 of the third sipe pattern in the tire width direction to the land portion width L3 of the third intermediate land portion is SW1 / L1>SW2 / L2>SW3 / L3.

17. The tire according to any one of claims 1 to 16, The tire includes a mounting direction display portion that specifies that the tire be mounted on the vehicle with a vehicle inner region thereof being positioned on the vehicle width direction inner side.

Images