pneumatic tires

Abstract

To provide a pneumatic tire that can achieve high wet braking characteristics and resistance to uneven wear even when subjected to loads exceeding 100% of its maximum load. [Solution] Tire 1 has a tread contact length of LC130, which is the circumferential length of the tire on the tire equatorial plane at 130% of the maximum load, an inner tread contact length of LI130, which is the circumferential length of the tire at a position 10 mm inward from the inner edge in the vehicle width direction of the contact width of the tire contact surface, and an outer tread contact length of LO130, which is the circumferential length of the tire at a position 10 mm inward from the outer edge in the vehicle width direction of the contact width of the tire contact surface. If the average rectangular ratio R130 = (((LI130 + LO130) / 2) / LC130) × 100 (%), then the average rectangular ratio R130 is 90% or more and 110% or less, and the inner tread contact length LI130 > outer tread contact length LO130.

Description

Technical Field

[0001] The present disclosure relates to pneumatic tires.

Background Art

[0002] Conventionally, in pneumatic tires, improvement in wear resistance and improvement in braking characteristics on a wet road surface have been demanded. Patent Document 1 focuses on the ratio between the contact length in the tire circumferential direction on the tire equatorial plane and the maximum contact length in the tire circumferential direction at a position separated from the tire equatorial plane, and discloses a technique for achieving both wet performance and uneven wear resistance performance.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] By the way, electric vehicles (EVs), which have been increasingly popular in recent years, are heavier than conventional engine - driven passenger cars. When the vehicle is heavy, the braking distance tends to be long, so improvement in braking characteristics, particularly wet braking characteristics, is required. Also, when the vehicle is heavy, tire wear tends to be promoted, so improvement in wear resistance is required. Therefore, in high - load vehicles, for example, even when assuming a load exceeding 100% of the maximum load, it is required to obtain high wet braking characteristics and uneven wear resistance characteristics.

[0005] An object of the present disclosure is to provide a pneumatic tire capable of obtaining high wet braking characteristics and uneven wear resistance characteristics even when a load exceeding 100% of the maximum load is applied.

Means for Solving the Problems

[0006] In the pneumatic tire disclosed herein, when mounted on a standard rim and filled to the standard internal pressure, the tread contact length is defined as LC130, which is the circumferential length of the tire on the tire equatorial plane at 130% of the maximum load, the inner tread contact length is defined as LI130, which is the circumferential length of the tire at a position 10 mm inward from the inner edge in the vehicle width direction of the contact width of the tire contact surface, and the outer tread contact length is defined as LO130, which is the circumferential length of the tire at a position 10 mm inward from the outer edge in the vehicle width direction of the contact width of the tire contact surface, and if the average rectangular ratio R130 = (((LI130 + LO130) / 2) / LC130) × 100 (%), then the average rectangular ratio R130 is 90% or more and 110% or less, and the inner tread contact length LI130 > outer tread contact length LO130. [Effects of the Invention]

[0007] According to this disclosure, high wet braking characteristics and resistance to uneven wear can be obtained even when the maximum load exceeds 100%. [Brief explanation of the drawing]

[0008] [Figure 1] This figure shows the internal structure of a tire 1, which is a pneumatic tire for a vehicle according to an embodiment, and is a half cross-sectional view in the tire axial direction on the outer side in the vehicle width direction. [Figure 2] This is an unfolded view of a portion of the tread surface 38 of tire 1. [Figure 3] This is a simplified diagram illustrating the shape of the tire contact patch, intended to explain the rectangular aspect ratio of the tire. [Figure 4] This contour diagram shows the contact surface shape and load ranges of tire 1 of this embodiment when it is loaded at 130% of the maximum load according to the ETRTO standard. [Figure 5] This contour diagram shows the contact surface shape and high / low load regions of tire 1 of this embodiment when it is loaded at 100% of its maximum load according to the ETRTO standard. [Modes for carrying out the invention]

[0009] The following describes one embodiment for implementing this disclosure with reference to drawings and other materials.

[0010] (Embodiment) Figure 1 is a diagram showing the internal structure of a tire 1, which is a pneumatic tire for a vehicle according to an embodiment, and is a half cross-sectional view in the tire axial direction on the outer side in the vehicle width direction. This tire 1 is suitable as a tire for passenger cars, and more suitable as a tire for electric vehicles (EVs). The cross-sectional view in Figure 1 is a cross-sectional view in the tire axial direction in an unloaded state, with the tire 1 mounted on a regular rim (not shown) and filled with the regular internal pressure.

[0011] As will be described later, the tread pattern 39 of the tire 1 in this embodiment is asymmetrical in the tire axial direction, and the orientation in which it is mounted on the vehicle, that is, the side that is positioned on the inside of the vehicle and the side that is positioned on the outside of the vehicle, is specified. In the following description, the side of the tire 1 that is positioned on the outside of the vehicle will be referred to as the outer side in the vehicle width direction, and the side that is positioned on the inside of the vehicle will be referred to as the inner side in the vehicle width direction. Furthermore, in the following description, it will be assumed that the tire 1 is correctly mounted in the specified orientation.

[0012] A standard rim is a rim defined by the tire standard, and in the case of ETRTO, it is called "Measuring Rim." Standard internal pressure is the air pressure defined by the tire standard, and in the case of ETRTO, it is called "INFLATION PRESSURE." The standard internal pressure is usually 250kPa for passenger car tires, but it is 290kPa for tires marked "Extra Load" or "Reinforced." Standard load is called "LOAD CAPACITY" in the case of ETRTO.

[0013] The internal structure of tire 1 is basically symmetrical in the cross-section along the tire axis. Figure 1 shows a half-cross-section of the right half of tire 1, and the left half, which is not shown, has the same internal structure. In Figure 1, the symbol S1 is the tire equatorial plane. The tire equatorial plane S1 is a plane perpendicular to the tire rotation axis and is located at the center in the tire axis direction.

[0014] Here, the tire axis direction is the direction parallel to the tire rotation axis, which is the left-right direction in Figure 1. In Figure 1, it is shown as the tire axis direction X. The inward direction in the tire axis direction is the direction approaching the tire equatorial plane S1, which is the left side of the paper in Figure 1. The outward direction in the tire axis direction is the direction away from the tire equatorial plane S1, which is the right side of the paper in Figure 1.

[0015] Furthermore, the tire radial direction is the direction perpendicular to the tire rotation axis, and corresponds to the vertical direction in Figure 1. In Figure 1, it is shown as the tire radial direction Y. The outer side of the tire radial direction is the direction away from the tire rotation axis, and corresponds to the upper side of the paper in Figure 1. The inner side of the tire radial direction is the direction closer to the tire rotation axis, and corresponds to the lower side of the paper in Figure 1.

[0016] As shown in Figure 1, the tire 1 comprises a pair of beads 10, a pair of sidewalls 20 extending radially outward from each of the bead 10, a tread 30 positioned between the pair of sidewalls 20, a shoulder 40 which is the transition from the sidewall 20 to the tread 30, a carcass ply 50 positioned across the pair of beads 10, and an inner liner 55 positioned on the inner side of the carcass ply 50.

[0017] A pair of beads 10 are positioned on both sides of the tire axial direction and at the inner ends in the tire radial direction. Each bead 10 includes a bead core 11, a bead filler 12 extending radially outward from the bead core 11, and a rim strip rubber 13.

[0018] The bead core 11 is an annular member in which a metal bead wire coated with rubber is wound multiple times in the tire circumferential direction. The bead core 11 is a member that serves to fix the air-filled tire 1 to the rim. The bead filler 12 has a tapered shape with a decreasing thickness as it extends from the inner side in the tire radial direction to the outer side in the tire radial direction. The bead filler 12 is provided to increase the rigidity of the peripheral portion of the bead 10 and ensure high maneuverability and stability. The bead filler 12 is composed of, for example, rubber having a higher hardness than the surrounding rubber members.

[0019] The rim strip rubber 13 further surrounds the outside of the carcass ply 50 provided to surround the bead core 11 and the bead filler 12. The rim strip rubber 13 contacts the inner surface of the rim to which the tire 1 is mounted.

[0020] The sidewall 20 includes a sidewall rubber 21 disposed on the outer side in the tire axial direction of the carcass ply 50. The sidewall rubber 21 constitutes the outer side surface in the tire circumferential direction of the tire 1. The sidewall rubber 21 is the most flexible part when the tire 1 acts as a cushion, and usually, a flexible rubber having fatigue resistance is adopted.

[0021] At the inner end 21a in the tire radial direction of the sidewall rubber 21, a rim line 21c protruding outward in the tire axial direction is formed. The rim line 21c is an annular line along the tire circumferential direction.

[0022] The tread 30 includes an endless belt 31 and a cap ply 34, and a tread rubber 37. The belt 31 is disposed on the outer side in the tire radial direction of the carcass ply 50. The cap ply 34 is disposed on the outer side in the tire radial direction of the belt 31. The tread rubber 37 is disposed on the outer side in the tire radial direction of the cap ply 34.

[0023] The belt 31 is a member that reinforces the tread 30. In this embodiment, the belt 31 has a two-layer structure comprising an inner belt 32 positioned on the outer side of the inner liner 55 in the tire radial direction, and an outer belt 33 positioned on the outer side of the inner belt 32 in the tire radial direction. Both the inner belt 32 and the outer belt 33 have a structure in which multiple belt cords, such as steel cords, are covered with rubber. The inner belt 32 is wider than the outer belt 33. By providing the belt 31, the rigidity of the tire 1 is ensured, and the contact of the tread 30 with the road surface is improved. Note that the belt 31 is not limited to a two-layer structure, but may have a single layer or a structure of three or more layers.

[0024] The cap ply 34 is a component that reinforces the tread 30 together with the belt 31. The cap ply 34 has a structure in which multiple insulating organic fiber cords, such as polyamide fibers, are covered with rubber. The cap ply 34 is wider than the belt 31 and covers the entire belt 31 from the outer surface side of the tire. The outer end 34a of the cap ply 34 in the tire axial direction is folded inward towards the inner cavity of the tire, making it double-layered, and this end 34a covers the outer ends 32a and 33a of the inner belt 32 and outer belt 33 in the tire axial direction from the outer surface side of the tire. By providing the cap ply 34, it is possible to improve the durability of the tire 1 and reduce road noise during driving. Note that the cap ply 34 is not limited to a single-layer structure as in the embodiment, but may have a two-layer or three-layer or more structure.

[0025] The tread rubber 37 is positioned radially outward of the cap ply 34. The outer surface of the tread rubber 37 constitutes the tread surface 38 that contacts the road surface. A tread pattern 39 is provided on the tread surface 38. The outer axial end 37a of the tread rubber 37 covers the radially outward end 21b of the sidewall rubber. In the example shown in Figure 1, the outer axial end 37a of the tread rubber 37 has a buttress 23a that protrudes outward in the axial direction of the tire, but the buttress 23a may be omitted.

[0026] The shoulder 40 is the portion where the sidewall 20 transitions to the tread 30. The shoulder 40 includes the axial outer edge 37a of the tread rubber 37.

[0027] In this embodiment, the tire 1 is shown as having a TOS (Tread-on-Side) structure. In the TOS structure, the axial end of the tread rubber 37 overlaps with the radially outer end of the sidewall rubber 21 on the axially outer side and is exposed on the tire's outer wall surface. The tire may also have a SWOT (Sidewall-on-Tread) structure. In the SWOT structure, the radially outer end of the sidewall rubber overlaps with the axial end of the tread rubber on the axially outer side and is exposed on the tire's outer wall surface.

[0028] The carcass ply 50 is stretched between a pair of beads 10. The carcass ply 50 is embedded inside the tire 1, passing between the pair of beads 10, through a pair of sidewalls 20, a pair of shoulders 40, and the inner side of the tread 30. On the tread 30, a belt 31 is positioned radially outward of the carcass ply 50.

[0029] The carcass ply 50 includes multiple ply cords (not shown) that form the framework of the tire 1. These multiple ply cords extend, for example, in a plane along the tire axial direction and are arranged in a line in the circumferential direction of the tire. The ply cords are made of insulating organic fiber cords such as polyester or polyamide. The multiple ply cords are covered with rubber to form the carcass ply 50.

[0030] The carcass ply 50 includes a ply body portion 50A and a pair of winding portions 50B. The ply body portion 50A is the portion that extends inward in the tire axial direction of each of the pair of beads 10, through each of the pair of shoulders 40 and the pair of sidewalls 20 from the tread 30. The pair of winding portions 50B are the portions that are folded outward in the tire radial direction by being wound around each of the pair of bead cores 11 from the ply body portion 50A and extend along the sidewall 20.

[0031] The ply body portion 50A is positioned on the inner side of the belt 31 in the tire radial direction on the tread 30, and on the inner side of the sidewall rubber 21 in the tire axial direction on the sidewall 20. The winding portion 50B is wound around the bead core 11 from the inner side to the outer side in the tire axial direction, then extends radially outward along the sidewall 20, and further reaches the outer end of the tread 30 in the tire axial direction. The portion of the winding portion 50B that is radially outward of the bead filler 12 is superimposed on the outer side of the ply body portion 50A in the tire axial direction. The end of the winding portion 50B is sandwiched between the outer end of the belt 31 in the tire axial direction and the ply body portion 50A, and its tip 50b is located inward in the tire axial direction from the outer tip 33b of the outer belt 33 in the tire axial direction.

[0032] The rim strip rubber 13 of the bead 10 described above surrounds the radially inner end of the carcass ply 50 that wraps around the bead core 11.

[0033] Although the carcass ply 50 in this embodiment has a single-layer structure, the carcass ply 50 may have two layers or three or more layers. A single-layer structure for the carcass ply 50 is preferable in that it reduces the weight of the tire 1.

[0034] The inner liner 55 covers the inner surface of the ply body portion 50A of the carcass ply 50 between the pair of beads 10, forming the inner surface of the tire. The inner liner 55 of this embodiment has a two-layer structure, comprising a first inner liner 55A on the inner surface side of the tire and a second inner liner 55B superimposed on the outer surface side of the first inner liner 55A. Each inner liner 55A and 55B is made of air-permeable rubber. The inner liner 55 prevents air from leaking out of the inner surface of the tire cavity. Note that the inner liner 55 may be a single-layer structure instead of a two-layer structure. In addition, on the inner side in the tire axial direction of the portion of the bead 10 that is radially inward of the tire, the rim strip rubber 13 covers the inner liner 55 and forms a part of the inner surface of the tire cavity.

[0035] In the embodiment of tire 1, a reinforcing rubber layer 56 is provided from the radially outer portion of the sidewall 20 through the shoulder 40 to the axially outer portion of the tread 30. This reinforcing rubber layer 56 is sandwiched between the second inner liner 55B and the ply body portion 50A of the carcass ply 50.

[0036] Here, the rubber used for the bead filler 12 is one that is at least harder than the sidewall rubber 21 and the inner liner 55. The hardness of the rubber is measured using the "Durometer hardness type A of JIS K6253-3:2012".

[0037] For example, using the hardness of the sidewall rubber 21 as a reference, the hardness of the bead filler 12 is preferably about 1.2 to 2.3 times the hardness of the sidewall rubber 21. The hardness of the rim strip rubber 13 is more preferably about 1 to 1.6 times the hardness of the sidewall rubber 21. By setting the hardness in this way, it is possible to ensure a balance between the flexibility of the tire and the rigidity around the bead 10.

[0038] The internal structure and layer configuration described above are merely illustrative examples and can be modified as appropriate.

[0039] Figure 2 is an unfolded view of a portion of the tread surface 38 of tire 1. In Figure 2, the tread pattern 39 shows the tire axial direction X, the inner and outer directions in the vehicle width direction, and the tire circumferential direction C. As mentioned above, Figure 2 is a partial plan view of the tread surface 38, and in Figure 2, the upper side of the paper will be referred to as the +C side and the lower side as the -C side for the following explanation. Note that in the tire 1 of this embodiment, the direction of rotation of tire 1 when the vehicle is moving forward changes depending on the position in which tire 1 is mounted. Therefore, the +C side and -C side are directions for convenience in explaining the tread pattern 39 and do not define the direction of rotation of the tire.

[0040] The tread pattern 39 of this embodiment has a plurality of ribs 60 and a plurality of main grooves 70 positioned between the plurality of ribs 60 and extending in the circumferential direction of the tire. Each of the plurality of ribs 60 is a rib that extends in an annular shape along the circumferential direction of the tire. Each of the plurality of main grooves 70 is a relatively wide groove that extends in an annular shape along the circumferential direction of the tire. The ribs 60 are responsible for contacting and rubbing against the road surface and for transmitting vehicle power to the road surface and for braking. The main grooves 70 are mainly responsible for draining the tire 1. In the following description, the width direction of the ribs 60 and main grooves 70 is synonymous with the axial direction of the tire (or tire width direction), and the width of the ribs 60 and main grooves 70 refers to the dimension in the axial direction of the tire.

[0041] The multiple main grooves 70 include a first inner main groove 71 and a second inner main groove 72, which are located inward in the vehicle width direction from the tire equatorial plane S1, and a first outer main groove 73 and a second outer main groove 74, which are located outward in the vehicle width direction from the tire equatorial plane S1. The first inner main groove 71 is located inward in the vehicle width direction from the tire equatorial plane S1. The second inner main groove 72 is located inward in the vehicle width direction from the first inner main groove 71. The first outer main groove 73 is located outward in the vehicle width direction from the tire equatorial plane S1. The second outer main groove 74 is located outward in the vehicle width direction from the first outer main groove 73.

[0042] The multiple main grooves 70 are arranged in order from widest to narrowest: the second inner main groove 72, the first inner main groove 71, the first outer main groove 73, and the second outer main groove 74. In other words, the groove width of the multiple main grooves 70 is widest at the innermost main groove 70 in the vehicle width direction, and the groove width increases as you move outward in the vehicle width direction, with the narrowest main groove 70 being the outermost main groove 70 in the vehicle width direction. The reason for this will be explained later.

[0043] The multiple landmasses 60 include a central landmass 61, an inner intermediate landmass 62, an inner shoulder landmass 63, an outer intermediate landmass 64, and an outer shoulder landmass 65.

[0044] The central groove 61 is located in a position that coincides with the tire equatorial plane S1, and is situated between the first inner main groove 71 and the first outer main groove 73, extending in the circumferential direction of the tire.

[0045] The inner intermediate ridge 62 is located between the tire equatorial plane S1 in the tire axial direction and the inner shoulder ridge 63 on the inner side in the vehicle width direction, and extends in the tire circumferential direction. That is, the inner intermediate ridge 62 is located between the first inner main groove 71 and the second inner main groove 72.

[0046] The inner shoulder ridge 63 is located at the inner edge in the vehicle width direction of the tread 30. That is, the inner shoulder ridge 63 is located on the tire axial side (inward in the vehicle width direction) of the second inner main groove 72.

[0047] The outer intermediate ridge 64 is located between the tire equatorial plane S1 in the tire axial direction and the outer shoulder ridge 65 on the outer side in the vehicle width direction, and extends in the tire circumferential direction. That is, the outer intermediate ridge 64 is located between the first outer main groove 73 and the second outer main groove 74.

[0048] The outer shoulder ridge 65 is located at the outer edge in the vehicle width direction of the tread 30. That is, the outer shoulder ridge 65 is located on the tire axial side (outer in the vehicle width direction) of the second outer main groove 74.

[0049] Of the multiple shoulder supports 60, the outer shoulder support 65 is positioned at the outermost edge in the vehicle width direction, and the inner shoulder support 63 is positioned at the innermost edge in the vehicle width direction. Both the outer shoulder support 65 and the inner shoulder support 63 are connected to the shoulder 40.

[0050] Furthermore, the width of the inner intermediate ramp 62 and the outer intermediate ramp 64 in the tire axis direction shall be ±10% of the width of the central ramp 61 in the tire axis direction. The reason for this will be explained later.

[0051] On the surface of each of the multiple land surfaces 60, multiple grooves are formed that extend in a direction intersecting the circumferential direction of the tire, forming the tread pattern 39. These grooves are sipes and slits, and are both spaced apart in the circumferential direction of the tire. Here, a sipe is a groove with a width of less than 1.5 mm, and a slit is a groove with a width of 1.5 mm or more.

[0052] Furthermore, in this embodiment, the main groove 70 and a portion of the sipes and slits have inclined surfaces that are inclined relative to the tread surface at the ridge line that forms the boundary between the tread surface 38 and the groove, and these inclined surfaces are also illustrated in Figure 2. However, these inclined surfaces can be omitted. Also, these inclined surfaces will not be included in the groove width, which will be described later.

[0053] Multiple first sipes 81, second sipes 82, and first slits 91 are arranged on the central landmass 61. Specifically, on the central landmass 61, the first sipes 81, second sipes 82, first sipes 81, and first slits 91 are arranged in this order from the -C side to the +C side, and this arrangement is repeated.

[0054] The first sipe 81 opens into and communicates with the first outer main groove 73, and from its opening end, it extends diagonally towards the +C side as it extends inward in the vehicle width direction, terminating at a position that slightly straddles the tire equatorial plane S1.

[0055] The second sipe 82 opens into and communicates with the first outer main groove 73, and from its opening end, extends diagonally to the +C side as it extends inward in the vehicle width direction, straddling the tire equatorial plane S1 and opening into and communicating with the first inner main groove 71.

[0056] The first slit 91 opens into and communicates with the first inner main groove 71, and from its opening end, it extends diagonally to the -C side as it extends outward in the vehicle width direction, crossing the tire equatorial plane S1 and terminating without reaching the first outer main groove 73.

[0057] Multiple third sipes 83 and second slits 92 are arranged on the inner intermediate ridge 62. Specifically, on the inner intermediate ridge 62, the third sipes 83 and second slits 92 are arranged in this order from the -C side to the +C side, and this arrangement is repeated. In other words, the third sipes 83 and second slits 92 are arranged alternately along the circumferential direction of the tire on the inner intermediate ridge 62.

[0058] The third sipe 83 opens into and communicates with the first inner main groove 71, and from its opening end, extends diagonally to the +C side as it extends inward in the vehicle width direction, and terminates without reaching the second inner main groove 72.

[0059] The second slit 92 opens into and communicates with the second inner main groove 72, and extends diagonally towards the -C side as it extends outward in the vehicle width direction from its opening end, and terminates without reaching the first inner main groove 71.

[0060] Furthermore, as shown in Figure 2, the first sipe 81, the second sipe 82, the first slit 91, the third sipe 83, and the second slit 92 all extend in a nearly straight line and are nearly parallel to each other when unfolded.

[0061] Multiple fourth sipes 84 and third slits 93 are arranged on the inner shoulder 63. Specifically, on the inner shoulder 63, the fourth sipes 84, the fourth sipes 84, and the third slits 93 are arranged in this order from the -C side to the +C side, and this arrangement is repeated.

[0062] The fourth sipe 84 is a transverse groove that is generally aligned with the tire axis, opening into and communicating with the second inner main groove 72. From its opening end, it extends diagonally towards the -C side as it extends inward in the vehicle width direction, and then bends towards the +C side. The fourth sipe 84 continues to extend inward in the vehicle width direction, curving gently so as it extends further inward in the vehicle width direction, becoming slightly convex towards the -C side.

[0063] The third slit 93 is a lateral groove generally aligned with the tire axis, opening into and communicating with the second inner main groove 72, and extending diagonally to the -C side as it extends inward in the vehicle width direction from its opening end. The third slit 93 then bends to the +C side midway, and as it continues to extend inward in the vehicle width direction, it gently curves, becoming slightly convex to the -C side, and as the profile of the shoulder 40 gradually moves away from the tread surface 38, the groove depth gradually becomes shallower and disappears. The groove width of the third slit 93 is narrow from the opening end to the second inner main groove 72 up to the point where it bends, the groove width widens near the point where it bends, and from the point where the groove width widens outward in the vehicle width direction, the groove width remains wide and constant.

[0064] The distance between the fourth sipe 84 and the fourth sipe 84 is approximately the same as the distance between the fourth sipe 84 and the third slit 93.

[0065] Multiple fifth sipes 85, sixth sipes 86, fourth slits 94, and fifth slits 95 are arranged on the outer intermediate ridge 64. Most of the fifth sipes 85 overlap with the fourth slits 94. Most of the sixth sipes 86 overlap with the fifth slits 95. Specifically, on the outer intermediate ridge 64, from the -C side to the +C side, the fourth slits 94 with the fifth sipe 85 and the fifth slits 95 with the sixth sipe 86 are arranged in this order, and this arrangement is repeated. In other words, on the outer intermediate ridge 64, the fourth slits 94 with the fifth sipe 85 and the fifth slits 95 with the sixth sipe 86 are arranged alternately in the circumferential direction of the tire. Note that the fifth sipes 85 and sixth sipes 86 may be omitted.

[0066] The fifth sipe 85 opens into and communicates with the first outer main groove 73, and from its opening end, it extends diagonally to the +C side as it extends outward in the vehicle width direction, and terminates without reaching the second outer main groove 74.

[0067] The sixth sipe 86 opens into and communicates with the second outer main groove 74, and from its opening end, it extends diagonally towards the -C side as it extends inward in the vehicle width direction, and terminates without reaching the first outer main groove 73.

[0068] The fourth slit 94 is positioned to overlap with the fifth sipe 85. That is, the fourth slit 94 opens into and communicates with the first outer main groove 73, and from its opening end, it extends diagonally to the +C side as it extends outward in the vehicle width direction, without reaching the second outer main groove 74, and terminates without reaching the outer end of the fifth sipe 85 in the vehicle width direction.

[0069] The fifth slit 95 is positioned to overlap with the sixth sipe 86. That is, it opens into and communicates with the second outer main groove 74, and from its opening end, it extends diagonally towards the -C side as it extends inward in the vehicle width direction, without reaching the first outer main groove 73, and terminates without reaching the inward end of the sixth sipe 86 in the vehicle width direction.

[0070] Furthermore, as shown in Figure 2, the fifth sipe 85, the sixth sipe 86, the fourth slit 94, and the fifth slit 95 all extend in a nearly straight line and are nearly parallel to each other when unfolded.

[0071] Multiple 7th sipes 87, 6th slits 96, and 7th slits 97 are arranged on the outer shoulder land 65. Specifically, on the outer shoulder land 65, the 7th sipes 87, 6th slits 96, 7th sipes 87, and 7th slits 97 are arranged in this order from the -C side to the +C side, and this arrangement is repeated.

[0072] The seventh sipe 87 is a lateral groove that generally follows the tire axis, opening into and communicating with the second outer main groove 74. From its opening end, it extends diagonally towards the +C side as it extends outward in the vehicle width direction, and then bends towards the -C side. The seventh sipe 87 extends almost straight outward in the vehicle width direction, slightly curving towards the +C side as it extends further outward in the vehicle width direction.

[0073] The sixth slit 96 is a lateral groove generally aligned with the tire axis, opening and communicating with the second outer main groove 74. From its opening end, it extends diagonally towards the +C side as it extends outward in the vehicle width direction, and then bends towards the +C side midway. The sixth slit 96 extends almost straight outward in the vehicle width direction, slightly curving towards the +C side as it extends further outward in the vehicle width direction, and the groove depth gradually decreases and disappears as the profile of the shoulder 40 gradually moves away from the tread surface 38.

[0074] The seventh slit 97 is a lateral groove generally aligned with the tire axis, opening and communicating with the second outer main groove 74. From its opening end, it extends diagonally towards the +C side as it extends outward in the vehicle width direction, and then bends towards the +C side midway. The seventh slit 97 extends almost straight outward in the vehicle width direction, slightly curving towards the +C side as it extends further outward in the vehicle width direction, and the groove depth gradually decreases and disappears as the profile of the shoulder 40 gradually moves away from the tread surface 38. The seventh slit 97 has a narrow groove width from its opening end to the second outer main groove 74 to near the bent portion, where the groove width widens, and from the point where the groove width widens outward in the vehicle width direction, it maintains a constant groove width.

[0075] The distance between the 7th sipe 87 and the 6th slit 96 is approximately the same as the distance between the 7th sipe 87 and the 7th slit 97.

[0076] As described above, the first sipe 81 to the seventh sipe 87 are all narrow grooves with a groove width of 1 mm or less. On the other hand, the groove width of the first slit 91 to the seventh slit 97 exceeds 1 mm and is larger than the groove width of the first sipe 81 to the seventh sipe 87. The spacing between the first sipe 81 to the seventh sipe 87 and the first slit 91 to the seventh slit 97 in the circumferential direction of the tire may be equal or unequal.

[0077] The tire 1 of this embodiment, having the above configuration, has a distinctive configuration in order to obtain high wet braking characteristics and resistance to uneven wear even when a load exceeding 100% of the maximum load is applied. The distinctive configuration will be described below for each aspect.

[0078] (Average rectangular ratio) The tire 1 of this embodiment has the following characteristics regarding the rectangularity when in contact with the road surface. Note that the standard rim, standard internal pressure, and maximum load below conform to the ETRTO tire standard. The rectangularity of a tire indicates the degree of rectangularity of the contact surface shape of the tire when the tire is mounted on a standard rim and filled with standard internal pressure and in contact with the road surface. Specifically, the rectangularity of a tire is the ratio of the circumferential length of the tire at a position 10 mm inward from both ends of the tire's contact surface shape in the axial direction to the circumferential length of the tire at the center of the tire's contact surface shape in the axial direction, i.e., on the tire's equatorial plane.

[0079] Figure 3 is a simplified diagram illustrating the shape of the tire contact surface and is intended to explain the rectangularity of the tire. As shown in Figure 3, in the tire contact surface shape F of the tread surface 38 of the tire 1 of the embodiment, LC is the tread contact length, which is the circumferential length of the tire on the tire equatorial plane S1. Also, LI is the inner tread contact length, which is the circumferential length of the tire at a position 10 mm inward from the inner end in the vehicle width direction of the contact width W of the tire contact surface shape F (inside the tire contact surface shape F). Furthermore, LO is the outer tread contact length, which is the circumferential length of the tire at a position 10 mm inward from the outer end in the vehicle width direction of the contact width W of the tire contact surface shape F (inside the tire contact surface shape F). In Figure 3, the inner tread contact length LI and the outer tread contact length LO are depicted as equal, but since actual LI and LO may differ, the average of both can be taken and divided by LC to calculate the average rectangularity R using the following formula.

[0080] Average rectangular rate R(%)=(((LI+LO) / 2) / LC)×100(%)

[0081] Here, the tire contact patch shape at 130% of the maximum load is defined as follows: With the tire mounted on a standard rim and filled to the standard internal pressure, the tread contact length, which is the circumferential length of the tire on the tire equatorial plane with the tire contact patch shape F at 130% of the maximum load, is defined as LC130. Furthermore, the inner tread contact length, which is the circumferential length of the tire at a position 10 mm inward from the inner edge in the vehicle width direction of the contact width W of the tire contact patch shape F, is defined as LI130. In addition, the outer tread contact length, which is the circumferential length of the tire at a position 10 mm inward from the outer edge in the vehicle width direction of the contact width W of the tire contact patch shape F, is defined as LO130. Then, the average rectangularity R130 at 130% of the maximum load can be calculated by the following formula.

[0082] Average rectangular rate R130=(((LI130+LO130) / 2) / LC130)×100(%)

[0083] The average rectangular ratio R130 of tire 1 at 130% of its maximum load, as calculated by the above formula, is preferably between 90% and 110%. When the average rectangular ratio R130 at 130% of the maximum load falls within this range, the contact patch shape of tire 1 under high load conditions becomes closer to a rectangular shape, suppressing uneven wear on the inner and outer shoulder contact points 63 and 65, thus preventing deterioration of wear resistance. Furthermore, improved handling stability can be achieved. Additionally, distortion of the shoulder 40 becomes less likely, resulting in reduced rolling resistance. Note that if the average rectangular ratio R130 falls below 90%, uneven wear near the center of the tire is more likely to occur, and if the average rectangular ratio R130 exceeds 110%, uneven wear near the shoulders is more likely to occur. Furthermore, it is even more desirable for the average rectangular ratio R130 to be between 95% and 105%.

[0084] Furthermore, the tire contact patch shape at 100% of the maximum load is defined as follows: With the tire mounted on a standard rim and filled to the standard internal pressure, the tread contact length, which is the circumferential length of the tire on the tire equatorial plane with the tire contact patch shape F at 100% of the maximum load, is defined as LC100. The inner tread contact length, which is the circumferential length of the tire at a position 10 mm inward from the inner edge in the vehicle width direction of the contact width W of the tire contact patch shape F, is defined as LI100. Furthermore, the outer tread contact length, which is the circumferential length of the tire at a position 10 mm inward from the outer edge in the vehicle width direction of the contact width W of the tire contact patch shape F, is defined as LO100. Here, similar to the average rectangular ratio R130 at 130% of the maximum load, the average rectangular ratio R100 at 100% of the maximum load can be calculated by the following formula.

[0085] Average rectangular rate R100=(((LI100+LO100) / 2) / LC100)×100(%)

[0086] The average rectangular ratio R100 of tire 1 at 100% of its maximum load, as determined by the above formula, is preferably 75% or more and less than 95%, and more preferably 80% or more and less than 90%.

[0087] Furthermore, it is desirable that the ratio of the calculated average rectangle ratio R100 to the above average rectangle ratio R130, R130 / R100, be between 100% and 120%, and even more desirable that it be between 110% and less than 120%.

[0088] When R130 / R100 is within the above range, uneven wear of the shoulder 40, including the inner shoulder 63 and outer shoulder 65, is suppressed under high load. As a result, handling stability is improved. In addition, distortion of the shoulder 40 is less likely to occur, resulting in reduced rolling resistance. If R130 / R100 falls below 100%, the shoulder 40 will have difficulty making contact with the ground, leading to a decrease in handling stability. On the other hand, if R130 / R100 exceeds 120%, the shoulder 40 will wear down more easily, leading to uneven wear.

[0089] (Tread contact length) Furthermore, in tire 1, it is desirable that the inner tread contact length LI130 > outer tread contact length LO130. When the inner tread contact length LI130 > outer tread contact length LO130, the contact length on the inner side in the vehicle width direction, which contributes significantly to braking, becomes longer, thereby improving wet braking characteristics.

[0090] Furthermore, for tire 1, when the tire contact patch is loaded at 130% of the maximum load, it is desirable that the inner tread contact length LI130 be 102% or more of the outer tread contact length LO130. Moreover, when the tire contact patch is loaded at 100% of the maximum load, it is desirable that the inner tread contact length LI110 be 103% or more of the outer tread contact length LO110. Furthermore, when the tire contact patch is loaded at 130% of the maximum load, it is desirable that the tread contact length LC130 on the tire equator is 110% to 125% of the tread contact length LC100 on the tire equator when the tire is loaded at 100% of the maximum load.

[0091] (Specific examples of ground contact shapes) Figure 4 is a contour map showing the contact patch shape and load intensity ranges for tire 1 of this embodiment at 130% of the maximum load according to ETRTO standards. Figure 5 is a contour map showing the contact patch shape and load intensity ranges for tire 1 of this embodiment at 100% of the maximum load according to ETRTO standards. Load intensity ranges are indicated by black (higher load) and white (lower load). Load intensity ranges represent the level of contact pressure with the road surface.

[0092] The values ​​mentioned above were obtained from the contact surface shapes shown in Figures 4 and 5, and were as follows. • Tire tread contact length on the equatorial plane at 130% of maximum load (LC130): 140.5 mm • Inner tread contact length (LI130) at 130% of maximum load: 136.7 mm • Outer tread contact length at 130% of maximum load (LO130): 130.4 mm • Tire tread contact length on the equatorial plane at 100% maximum load: LC100: 119.4 mm • Inner tread contact length at 100% maximum load (LI100): 101.7 mm • Outer tread contact length at 100% maximum load (LO100): 95.7 mm • Average rectangular ratio R130 at 130% of maximum load: 95.0% • Average rectangular ratio R100 at 100% of maximum load: 82.7% • R130 / R100: 114.9%

[0093] Thus, the contact patch shape of the tire 1 in this embodiment, particularly under a load of 130% of the maximum load, is within the desirable range and relative magnitudes for both the average rectangularity and tread contact length. Therefore, uneven wear can be suppressed, handling stability can be improved, and wet braking characteristics can be enhanced.

[0094] (Placement of sipes) Furthermore, in the tire 1 of this embodiment, as shown in Figure 2, the number of sipes provided on the inner shoulder ridge 63 on the inner side in the vehicle width direction is greater than the number of sipes provided on the outer shoulder ridge 65 on the outer side in the vehicle width direction. In other words, there are more fourth sipes 84 than seventh sipes 87. Specifically, in this embodiment, there are 136 fourth sipes 84 and 90 seventh sipes 87 around the entire circumference of the tire 1.

[0095] By increasing the number of sipes on the inner shoulder ridge 63 compared to the number of sipes on the outer shoulder ridge 65, the rigidity of the outer shoulder ridge 65 can be relatively increased, thereby improving handling stability. Furthermore, by increasing the number of sipes on the inner shoulder ridge 63 compared to the number of sipes on the outer shoulder ridge 65, the drainage performance on the inner side in the width direction, which contributes significantly to braking, can be improved, thereby improving wet braking characteristics.

[0096] (Void ratio relative to the tire's equatorial plane) As described above, the tread surface 38 of tire 1 has voids (spaces) due to a plurality of main grooves 70 and a plurality of slits (first slit 91 to seventh slit 97). The ratio of voids due to these main grooves and slits differs between the region on the inside in the vehicle width direction and the region on the outside in the vehicle width direction, with respect to the tire equatorial plane S1. In the tire 1 of this embodiment, the ratio of inner voids on the inside in the vehicle width direction relative to the tire equatorial plane S1 is greater than the ratio of outer voids on the outside in the vehicle width direction relative to the tire equatorial plane S1. This reduces the effective contact area on the inside in the vehicle width direction, which has a high contribution during braking, and the proportion of voids is higher on the inside in the vehicle width direction, thus improving drainage and wet braking characteristics. In addition, the effective contact area on the outside in the vehicle width direction is increased, which improves handling stability.

[0097] Furthermore, in configurations where the internal void ratio is greater than the external void ratio, it is desirable that, for example, the internal void ratio be between 35% and 45%, and the external void ratio be between 28% and 38%. By setting the internal and external void ratios within the above numerical ranges, it is possible to obtain near-ideal characteristics that balance drainage performance and maneuverability. In this embodiment, the internal void ratio is 39%, and the external void ratio is 34%.

[0098] In calculating the void ratio described above, and the main groove void ratio described later, the void ratio shall be determined as the ratio of the area of ​​the main grooves, slits, and sipes with a depth of 1 mm or more within the contact surface. Furthermore, the calculation of the void ratio and the main groove void ratio described later shall be performed on a development diagram as shown in Figure 2, covering the entire circumference of the tire. That is, on the development diagram covering the entire circumference of the tire, the area of ​​the land, and the areas of the main grooves, slits, and sipes are determined, and the void ratio and main groove void ratio are determined as the ratio of these areas.

[0099] (Main groove void ratio relative to the tire's equatorial plane) Furthermore, the void ratio obtained by considering only the main groove 70 as a void, without including the slits, is defined as the main groove void ratio. In this embodiment, the inner main groove void ratio, which is the void ratio of only the main grooves on the inside in the vehicle width direction relative to the tire equatorial plane S1, is greater than the outer main groove void ratio, which is the void ratio of only the main grooves on the outside in the vehicle width direction relative to the tire equatorial plane S1. As a result, the effective contact area on the inside in the vehicle width direction, which has a high contribution during braking, is reduced, and the proportion of voids is higher on the inside in the vehicle width direction, so drainage can be improved and wet braking characteristics can be improved. In addition, the effective contact area on the outside in the vehicle width direction is increased, so handling stability can be improved.

[0100] Furthermore, in a configuration where the inner main groove void ratio is greater than the outer main groove void ratio, it is desirable that, for example, the inner main groove void ratio be between 27% and 37%, and the outer main groove void ratio be between 20% and 30%. By setting the inner and outer main groove void ratios within the above numerical ranges, it is possible to obtain characteristics close to ideal, with a balance between drainage and handling stability. In this embodiment, the inner main groove void ratio is 29%, and the outer main groove void ratio is 22%.

[0101] (Size of the main groove width) Furthermore, as explained earlier, the multiple main grooves 70 are arranged in order from widest to narrowest: the second inner main groove 72, the first inner main groove 71, the first outer main groove 73, and the second outer main groove 74. In other words, the groove width of the multiple main grooves 70 is widest for the main groove 70 located furthest in the vehicle width direction, and the groove width increases as you move outward in the vehicle width direction, with the main groove 70 located furthest out in the vehicle width direction having the narrowest groove width. By adopting this configuration, the relationship between the void ratio and the main groove void ratio, as described above, based on the tire equatorial plane S1, can be specifically realized.

[0102] (The relative widths of the central landmass 61, the inner intermediate landmass 62, and the outer intermediate landmass 64) Furthermore, as explained earlier, the axial width of the inner intermediate land area 62 and the outer intermediate land area 64 is set to ±10% of the axial width of the central land area 61. This configuration equalizes the pressure on each land area when it comes into contact with the ground, allowing each land area to make effective contact during both wet and dry braking. In addition, the difference in wear between land areas is reduced, thus suppressing uneven wear.

[0103] (Arrangement of slits and sipes in the inner intermediate landmass 62 and outer intermediate landmass 64) As explained earlier, the inner intermediate ridge 62 has slits (second slit 92), which are grooves with a component extending in the tire axial direction, and sipes (third sipe 83), which are grooves with a narrower groove width than the slits and a component extending in the tire axial direction, arranged alternately in the tire circumferential direction. The outer intermediate ridge 64 has slits (a fourth slit 94 on which a fifth sipe 85 is formed, and a fifth slit 95 on which a sixth sipe 86 is formed) arranged side by side in the tire circumferential direction. In this embodiment, the fifth sipe 85 is arranged on top of the fourth slit 94, and the sixth sipe 86 is arranged on top of the fifth slit 95, so in effect, the outer intermediate ridge 64 can be considered to have the fourth slit 94 and the fifth slit 95 arranged alternately. Furthermore, the reason why the fifth sipe 85 is positioned overlapping the fourth slit 94 and the sixth sipe 86 is positioned overlapping the fifth slit 95 is to enhance the drainage performance by the fourth slit 94 and the fifth slit 95 while suppressing a decrease in the rigidity of the outer intermediate landmass 64.

[0104] As described above, in the tire 1 of this embodiment, slits (second slit 92) and sipes (third sipe 83) are arranged alternately in the circumferential direction of the tire on the inner intermediate rim 62. Furthermore, slits (fourth slit 94 and fifth slit 95) are arranged side by side in the circumferential direction of the tire on the outer intermediate rim 64. This arrangement of slits and sipes makes it possible to achieve both the effect of improving wet braking characteristics by enhancing drainage on the inner side in the vehicle width direction, which contributes greatly to braking, and the effect of improving handling stability by increasing rigidity on the outer side in the vehicle width direction, which contributes greatly to turning the vehicle. In this embodiment, a fifth sipe 85 and a sixth sipe 86 are arranged on the outer intermediate rim 64 to further enhance drainage, but if you want to further enhance handling stability, you can omit the fifth sipe 85 and the sixth sipe 86.

[0105] The tire 1 according to the embodiment described above provides the following effects.

[0106] (1) In this embodiment, the tire 1, when mounted on a standard rim and filled with standard internal pressure, has a tread contact length of LC130, which is the circumferential length of the tire on the tire equatorial plane at 130% of the maximum load, in the tire standard ETRTO, the inner tread contact length of LI130, which is the circumferential length of the tire at a position 10 mm inward from the inner edge in the vehicle width direction of the contact width of the tire contact surface, and the outer tread contact length of LO130, which is the circumferential length of the tire at a position 10 mm inward from the outer edge in the vehicle width direction of the contact width of the tire contact surface, and the average rectangular ratio R130 = (((LI130 + LO130) / 2) / LC130) × 100 (%), and the average rectangular ratio R130 is 90% or more and 110% or less, and the inner tread contact length LI130 > outer tread contact length LO130.

[0107] As a result, the contact patch shape of the tire 1 under high load conditions becomes closer to a rectangular shape, suppressing uneven wear on the inner shoulder contact patch 63 and outer shoulder contact patch 65, and preventing deterioration of wear resistance. Furthermore, handling stability can be improved. In addition, distortion of the shoulder 40 becomes less likely, resulting in reduced rolling resistance. Moreover, the contact length on the inner side in the vehicle width direction, which contributes significantly to braking, becomes longer, improving wet braking characteristics.

[0108] (2) In the pneumatic tire described in (1), the number of sipes (4th sipe 84) provided on the inner shoulder 63 on the inner side in the vehicle width direction is greater than the number of sipes (7th sipe 87) provided on the outer shoulder 65 on the outer side in the vehicle width direction.

[0109] This allows for a relative increase in the rigidity of the outer shoulder rim 65, thereby improving handling stability. Furthermore, by increasing the number of sipes on the inner shoulder rim 63 compared to the number of sipes on the outer shoulder rim 65, the drainage performance on the inner side in the vehicle width direction, which contributes significantly to braking, can be improved, thereby enhancing wet braking characteristics.

[0110] (3) In the pneumatic tire described in (1) or (2), the inner main groove void ratio, which is the void ratio of only the main grooves 70 located on the inside in the vehicle width direction relative to the tire equatorial plane S1, is greater than the outer main groove void ratio, which is the void ratio of only the main grooves 70 located on the outside in the vehicle width direction relative to the tire equatorial plane S1.

[0111] This reduces the effective contact area on the inner side in the vehicle width direction, which contributes significantly to braking, and increases the proportion of voids on the inner side in the vehicle width direction. This improves drainage and enhances wet braking characteristics. Additionally, the increased effective contact area on the outer side in the vehicle width direction improves handling stability.

[0112] (4) In the pneumatic tire described in (3), the inner main groove void ratio is 27% or more and 37% or less, and the outer main groove void ratio is 20% or more and 30% or less.

[0113] This makes it possible to obtain near-ideal characteristics that balance drainage and handling stability.

[0114] (5) In a pneumatic tire as described in any of (1) to (4), there is an inner intermediate ridge 62 that extends in the tire circumferential direction and is located between the tire equatorial plane S1 in the tire axial direction and the inner shoulder ridge 63 on the inside in the vehicle width direction, and an outer intermediate ridge 64 that extends in the tire circumferential direction and is located between the tire equatorial plane S1 in the tire axial direction and the outer shoulder ridge 65 on the outside in the vehicle width direction, wherein the inner intermediate ridge 62 has slits (second slit 92) which are grooves having a component that extends in the tire axial direction and sipes (third sipe 83) which are grooves having a groove width narrower than the slits (second slit 92) and a component that extends in the tire axial direction, arranged alternately in the tire circumferential direction, and the outer intermediate ridge 64 has slits (fourth slit 94 and fifth slit 95) arranged side by side in the tire circumferential direction.

[0115] This makes it possible to achieve both the effect of improving wet braking characteristics by enhancing drainage on the inner side in the vehicle width direction, which contributes significantly to braking, and the effect of improving handling stability by increasing rigidity on the outer side in the vehicle width direction, which contributes significantly to vehicle cornering.

[0116] (Transformed form) The embodiments described above are not limited to those described above, and various modifications and changes are possible, which are also within the scope of this disclosure.

[0117] (Modified form 1) In this embodiment, a tire 1 having a central ridge 61 is illustrated. However, the invention is not limited to this, and for example, a tire without a ridge corresponding to the central ridge 61 may also be used.

[0118] (Modified form 2) In the embodiment, the main grooves 70 are shown as extending straight along the tire circumferential direction. However, the embodiment is not limited to this, and for example, the main grooves may be configured such that the groove position in the tire axial direction shifts inward or outward in the vehicle width direction depending on the position in the tire circumferential direction. That is, the main grooves may be zigzag main grooves in which the groove shape, when viewed from the outside in the tire radial direction, is zigzag and extends in the tire circumferential direction. In this case, the inner main groove void ratio and the outer main groove void ratio described above should be such that the main groove void ratio obtained using the area of ​​the zigzag groove shape satisfies the above conditions. Furthermore, the inner main groove void ratio and the outer main groove void ratio described above may be such that the main groove void ratio obtained as the so-called see-through main groove void ratio satisfies the above conditions. In other words, the inner see-through main groove void ratio, which is the void ratio of the main groove only on the inside in the vehicle width direction relative to the tire equator, may be greater than the outer see-through main groove void ratio, which is the void ratio of the main groove only on the outside in the vehicle width direction relative to the tire equator. Furthermore, the inner see-through main groove voids may be set to 27% or more and 37% or less, and the outer see-through main groove voids may be set to 20% or more and 30% or less. In this case as well, the same effects as tire 1 of the embodiment can be obtained. Here, the see-through main groove void ratio is the proportion of the main groove where no land exists when the main groove is viewed in the tire circumferential direction. In other words, the see-through void ratio is the void ratio of the main groove only when the area where the space of the main groove extends without being obstructed by land in the tire circumferential direction is considered as the void of the main groove.

[0119] The embodiments and variations may be used in combination as appropriate, but a detailed explanation is omitted. Furthermore, this disclosure is not limited to the embodiments described above. [Explanation of symbols]

[0120] 1 tire 10 beads 11 Bead core 12 Bead Fillers 13 Rim strip rubber 20 Sidewall 21 Sidewall rubber 21c Rimline 23a Buttress 30 tread 31 belt 32 Inner belt 33 Outer belt 34 Cap Ply 37 Tread Rubber 38 Tread surface 39 Tread Pattern 40 Shoulder 50 Carcass Ply 55 Inner Liner 60 land 61 Chuo Riku 62 Inner Middle Land 63 Inner shoulder land 64 Outer intermediate land 65 Outer shoulder land 70 Main groove 71 1st inner main groove 72 2nd inner main groove 73 1st outer main groove 74 2nd outer main groove 81. First Sipe 82. Second Sipe 83 Third Sipe 84. Fourth Sipe 85. Fifth Sipe 86. Sixth Sipe 87. Seventh Sipe 91 First Slit 92 Second Slit 93 Third Slit 94 Fourth Slit 95 Fifth Slit 96. Slit No. 6 97. Slit No. 7

Claims

1. In the tire standard ETRTO, With the tire mounted on a standard rim and filled to the standard internal pressure, the tread contact length, which is the circumferential length of the tire on the tire's equatorial plane at 130% of the maximum load, is defined as LC130. The inner tread contact length, which is the tire circumferential length at a position 10 mm inward from the inner edge in the vehicle width direction of the contact width of the tire contact surface shape, is defined as LI130. The outer tread contact length, which is the tire circumferential length at a position 10 mm inward from the outer edge in the vehicle width direction of the contact width of the tire contact surface shape, is defined as LO130. If the average rectangle ratio R130 = (((LI130 + LO130) / 2) / LC130) × 100 (%), The average rectangle ratio R130 is between 90% and 110%, and A pneumatic tire where the inner tread contact length LI130 > outer tread contact length LO130.

2. In the pneumatic tire described in claim 1, A pneumatic tire in which the number of sipes on the inner shoulder of the tire on the inside in the width direction is greater than the number of sipes on the outer shoulder of the tire on the outside in the width direction.

3. In the pneumatic tire according to claim 1 or claim 2, A pneumatic tire in which the inner main groove void ratio, which is the void ratio of the main grooves only on the side of the tire width relative to the tire's equator, is greater than the outer main groove void ratio, which is the void ratio of the main grooves only on the side of the tire width relative to the tire's equator.

4. In the pneumatic tire described in claim 3, The void ratio of the inner main groove is 27% or more and 37% or less. A pneumatic tire in which the outer main groove void ratio is 20% or more and 30% or less.

5. In the pneumatic tire according to claim 1 or claim 2, Located between the tire's equatorial plane in the tire's axial direction and the inner shoulder land on the vehicle's width side, the inner intermediate land extends in the tire's circumferential direction, Located between the tire's equatorial plane in the tire's axial direction and the outer shoulder land on the outside in the vehicle's width direction, the outer intermediate land extends in the tire's circumferential direction, It has, In the aforementioned inner intermediate land, slits, which are grooves having a component extending in the tire axial direction, and sipes, which are grooves having a narrower groove width than the slits and a component extending in the tire axial direction, are arranged alternately in the tire circumferential direction. A pneumatic tire in which the slits are arranged in a line in the circumferential direction of the tire on the outer intermediate land area.

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