Tire

Abstract

The present invention relates to a tire. With a tire in which a tread portion is composed of five land portions, wet performance is maintained, and noise performance and braking performance are improved. The tire has a tread portion (2) in which the orientation toward the vehicle on which the tire is mounted is specified. The tread portion (2) includes five land portions (4) that are divided by four circumferential grooves (3). Among the five land portions (4), the more the land portion (4) is located on the outer side tread end (To) side, the greater the width of the tire in the tire axial direction on the ground surface is made. The inner side shoulder land portion (11) is the smallest among the five land portions (4) in terms of the width of the tire in the tire axial direction on the ground surface. An inner side shoulder cross groove (16) extends from an inner end that is separated by a distance from the inner side shoulder circumferential groove (5) in the tire axial direction to a position beyond the inner side tread end (Ti). An inner side shoulder sipe (17) extends from the inner side shoulder circumferential groove (5) to a position beyond the inner side tread end (Ti).

Description

Technical Field

[0001] This disclosure relates to tires. Background Technology

[0002] Previously, various tires with a tread surface consisting of five land sections in the axial direction of the tire have been proposed (hereinafter, sometimes referred to as "5-rib tires"). In addition, the pneumatic tire of Patent Document 1 described below is a 5-rib tire, which improves lateral stiffness and is expected to improve handling stability by restricting the volume ratio of each groove of the crown rib, the middle rib and the shoulder rib in relation to each other.

[0003] Patent Document 1: Japanese Patent Application Publication No. 2012-017001

[0004] However, in recent years, tire requirements have focused on both reducing exterior noise and improving braking performance, a trend particularly pronounced in Europe. Reducing the volume of the tread grooves is considered effective in achieving both. However, this approach often results in a deterioration in wet-weather performance. Summary of the Invention

[0005] This disclosure is made in view of the above-mentioned practical situation, and the main objective is to maintain wet performance and improve noise performance and braking performance based on a tire with a tread consisting of 5 land sections.

[0006] This disclosure discloses a tire having a tread portion with a specified orientation for mounting to a vehicle. The tread portion includes: an outer tread end that becomes the outer side of the vehicle when mounted on the vehicle; an inner tread end that becomes the inner side of the vehicle when mounted on the vehicle; four circumferential grooves extending continuously in the tire circumferential direction between the outer tread end and the inner tread end; and five land portions divided by the four circumferential grooves. The four circumferential grooves include an inner shoulder circumferential groove disposed within the circumferential grooves on the side closest to the inner tread end. Of the five land portions, the land portion located closest to the outer tread end has a larger contact surface area. The wider the axial width of the tire, the more the five land portions are formed. The inner shoulder land portion is provided on the outer side of the inner shoulder circumferential groove in the tire axial direction. The inner shoulder land portion is the smallest among the five land portions in terms of the axial width of the tire contacting the ground. The inner shoulder land portion is provided with a plurality of inner shoulder transverse grooves and a plurality of inner shoulder sipes. The inner shoulder transverse grooves extend from the inner end of the inner shoulder circumferential groove in the tire axial direction to a position beyond the inner tread end. The inner shoulder sipes extend from the inner shoulder circumferential groove to a position beyond the inner tread end.

[0007] The tire disclosed herein, by employing the above-described structure, can maintain wet performance and improve noise performance and braking performance. Attached Figure Description

[0008] Figure 1 This is a unfolded view of the tread portion of an embodiment of the present disclosure.

[0009] Figure 2 It is an enlarged view showing the shape of the contact patch when the tire tread touches the ground.

[0010] Figure 3 yes Figure 1 Enlarged view of the inner shoulder land area and the inner middle land area.

[0011] Figure 4 yes Figure 3 A sectional view along line AA.

[0012] Figure 5 yes Figure 1 Enlarged view of the land portion of the tibial crown, the middle outer land portion, and the land portion of the outer shoulder of the tibial crown.

[0013] Figure 6 yes Figure 5 BB line section view.

[0014] Figure 7 This is an enlarged view of the outer shoulder sipe and the outer middle transverse groove.

[0015] Figure 8 yes Figure 5 CC-line sectional view.

[0016] Figure 9 This is an enlarged view of the inner shoulder land portion and the inner middle land portion of the tread portion in other embodiments of this disclosure.

[0017] Figure 10 This is an enlarged view of the outer middle transverse groove in other embodiments.

[0018] Figure 11 It means Figure 10 An enlarged 3D view of the interior of the horizontal groove in the middle of the outer side.

[0019] Figure 12 yes Figure 10 DD-line sectional view.

[0020] Figure 13 yes Figure 10 EE line section view.

[0021] Figure 14 yes Figure 10 FF line section view.

[0022] Figure 15 This is a unfolded view of the tread area of ​​another embodiment of this disclosure.

[0023] Figure 16 yes Figure 15 Enlarged view of the outer shoulder land area and the outer middle land area.

[0024] Figure 17 yes Figure 16 GG line sectional view.

[0025] Figure 18 yes Figure 16 HH-line cross-sectional view.

[0026] Figure 19 This is an enlarged view of the land portion of the inner shoulder of the comparative example.

[0027] Figure 20 This is an enlarged view of the outer shoulder land area and the outer middle land area of ​​the reference example. Detailed Implementation

[0028] Hereinafter, an embodiment of the present disclosure will be described with reference to the accompanying drawings. Figure 1 This is a developed view showing the tread portion 2 of a tire 1 according to one embodiment of the present disclosure. The tire 1 of this embodiment is suitable, for example, for use as a pneumatic tire for passenger vehicles. However, the present disclosure is not limited to this method and can be applied to pneumatic tires for heavy loads or non-pneumatic tires whose interior is not filled with pressurized air.

[0029] like Figure 1 As shown, the tire 1 of this disclosure has a tread portion 2 that specifies the orientation for mounting to a vehicle. The tread portion 2 has an outer tread end To that becomes the outer side of the vehicle when the tire 1 is mounted to the vehicle, and an inner tread end Ti that becomes the inner side of the vehicle when mounted to the vehicle. The orientation for mounting to the vehicle is indicated by text or symbols, for example, on the sidewall portion (not shown).

[0030] The outer tread end To and the inner tread end Ti are respectively the outermost contact points of the tire axial direction when the tire 1 is loaded with 50% of the normal load and touches the ground at a camber angle of 0°.

[0031] "Standard condition" in the context of specified pneumatic tire sizes refers to the condition where the tire is mounted on a standard rim, inflated to the standard internal pressure, and unloaded. In the case of tires without specified sizes, or non-pneumatic tires, the above-mentioned standard condition refers to the standard operating condition corresponding to the tire's intended use, unloaded and not mounted on a vehicle. In this manual, unless otherwise specified, the dimensions of the tire are values ​​measured under the above-mentioned standard condition.

[0032] "Standard rim" refers to a rim with a specified specification for each tire within a specification system that includes the specifications on which the tire is based. For example, JATMA is "standard rim", TRA is "Design Rim", and ETRTO is "Measuring Rim".

[0033] "Standard internal pressure" refers to the air pressure specified for each tire in the specification system, including the specifications on which the tire is based. If it is JATMA, it is the "maximum air pressure". If it is TRA, it is the maximum value recorded in the table "TIRE LOAD LIMITS ATVARIOUS COLD INFLATION PRESSURES". If it is ETRTO, it is the "INFLATION PRESSURE".

[0034] "Regular load," when various sizes of pneumatic tires are specified, refers to the load specified for each tire according to its specifications within a specification system that includes the specifications the tire is based on. For JATMA, it is "maximum load capacity"; for TRA, it is the maximum value recorded in the table "TIRE LOAD LIMITS AT VARIOUS COLD INFLATION PRESSURES"; and for ETRTO, it is "LOAD CAPACITY". Furthermore, when tires are not specified in terms of various sizes, or when using non-pneumatic tires, "regular load" refers to the load acting on a tire under its standard mounting condition. The aforementioned "standard mounting condition" refers to the condition where the tire is mounted on a standard vehicle corresponding to the tire's intended use, and the vehicle is stationary on a flat road surface in a drivable state.

[0035] The tread portion 2 includes: four circumferential grooves 3 extending continuously along the tire circumference between the outer tread end To and the inner tread end Ti, and five land portions 4 divided by the four circumferential grooves 3.

[0036] The circumferential groove 3 includes an inner shoulder circumferential groove 5 located on the innermost tread end Ti side among the four circumferential grooves 3. Furthermore, the circumferential groove 3 also includes an inner crown circumferential groove 6, an outer shoulder circumferential groove 7, and an outer crown circumferential groove 8. The inner crown circumferential groove 6 is located between the tire equator C and the inner shoulder circumferential groove 5. The outer shoulder circumferential groove 7 is located on the outermost tread end To side among the four circumferential grooves 3. The outer crown circumferential groove 8 is located between the outer shoulder circumferential groove 7 and the tire equator C.

[0037] The axial distance L1 from the tire equator C to the center line of the outer shoulder circumferential groove 7 or the inner shoulder circumferential groove 5 is preferably 25% to 35% of the tread width TW. The axial distance L2 from the tire equator C to the center line of the outer crown circumferential groove 8 or the inner crown circumferential groove 6 is preferably 5% to 15% of the tread width TW. Here, the tread width TW refers to the axial distance from the outer tread end To to the inner tread end Ti in the above-described normal state.

[0038] In this embodiment, each circumferential groove 3 extends in a straight line, parallel to the tire circumference. Each circumferential groove 3 may also extend in a corrugated shape.

[0039] In this embodiment, the circumferential groove 3 has a groove width of 3.0 mm or more. The groove width W1 of each circumferential groove 3 is preferably, for example, 2.0% to 8.0% of the tread width TW. In this embodiment, the outer shoulder circumferential groove 7 has the smallest groove width among the four circumferential grooves 3. However, this disclosure is not limited to this method. In the case of pneumatic tires for passenger cars, the depth of each circumferential groove 3 is, for example, 5 to 10 mm.

[0040] The five land portions 4 include an inner shoulder land portion 11 located on the axially outer side of the inner shoulder circumferential groove 5. The five land portions 4 also include an outer shoulder land portion 12, an outer intermediate land portion 13, a crown land portion 14, and an inner intermediate land portion 15. The outer shoulder land portion 12 is located on the axially outer side of the outer shoulder circumferential groove 7. The outer intermediate land portion 13 is defined between the outer shoulder circumferential groove 7 and the outer crown circumferential groove 8. The crown land portion 14 is defined between the outer crown circumferential groove 8 and the inner crown circumferential groove 6. The inner intermediate land portion 15 is defined between the inner shoulder circumferential groove 5 and the inner crown circumferential groove 6.

[0041] Figure 2 An enlarged view showing the contact patch shape of the tread 2 when it touches the ground is displayed. This contact patch shape refers to the shape of the contact patch when the tire 1 in its normal state is subjected to 50% of the normal load and is grounded at a 0° camber angle on a flat surface. Figure 2 As shown in this disclosure, the inner shoulder land portion 11 is the smallest among the five land portions 4 in terms of the axial width of the tire contact surface.

[0042] Figure 3 An enlarged view is shown of the inner shoulder land portion 11 and the inner middle land portion 15. (See diagram below.) Figure 3 As shown, multiple inner shoulder transverse grooves 16 and multiple inner shoulder sipes 17 are provided on the inner shoulder land portion 11.

[0043] The inner shoulder lateral groove 16 extends from its inner end 16a, which is spaced apart from the inner shoulder circumferential groove 5 in the tire axial direction, to a position beyond the inner tread end Ti. Additionally, the inner shoulder sipe 17 extends from the inner shoulder circumferential groove 5 to a position beyond the inner tread end Ti.

[0044] Figure 4 Show Figure 3 A sectional view along line AA. Figure 4 As an example of a cross-section of a sipe, a cross-section of the inner shoulder sipe 17 is shown. In this specification, "sipe" refers to a grooving element with a small width, specifically a structure in the main body portion 40 comprising two substantially parallel opposing wall surfaces 41 with a width of 1.5 mm or less between the two wall surfaces 41. The width of the sipe is preferably 0.5 to 1.5 mm. The sipe can be a structure extending with a constant width from an opening at the outer surface of the tire portion 2 to the bottom, or it can be a structure where one or both edges of the sipe appearing on both sides of the outer surface of the tire portion 2 are formed by a chamfer 18. The chamfer 18 is formed by an inclined surface 18a connected to the outer surface of the tire portion 2 and the aforementioned wall surface 41. Where the chamfer 18 is formed, the opening width of the sipe can exceed 1.5 mm. Furthermore, the bottom of the sipe can be connected to a flask bottom with a width exceeding 1.5 mm.

[0045] The tire disclosed herein, by employing the above-described structure, can maintain wet performance and improve noise performance and braking performance. The following mechanism can be deduced as a reason for this.

[0046] like Figure 2 as well as Figure 3 As shown in this disclosure, because the contact patch width of the inner shoulder land portion 11 is small, it easily cuts through the water film on wet surfaces during driving, thus maintaining wet performance. Furthermore, this type of inner shoulder land portion 11 also reduces knocking noise upon contact with the ground. Additionally, because the inner shoulder transverse groove 16 is not connected to the inner shoulder circumferential groove 5, suction noise is low, and further improvement in noise performance can be expected.

[0047] On the other hand, the developers of this disclosure have discovered the following trend: the combination of the narrow inner shoulder land portion 11 and the inner shoulder transverse groove 16 that is not connected to the inner shoulder circumferential groove 5 can easily lead to deformation of the ground contact area when it touches the ground, resulting in uneven ground pressure and impaired braking performance.

[0048] To address this adverse condition, as described above, in this disclosure, an inner shoulder groove 17 is provided on the inner shoulder land portion 11. This reduces deformation of the contact patch, resulting in more uniform contact pressure and superior braking performance. Based on this mechanism, it is inferred that the tire of this disclosure can maintain wet performance and improve noise and braking performance.

[0049] like Figure 4 As shown, as a further preferred embodiment, in this embodiment, the edges of the grooves on both sides of each inner shoulder groove 17 are formed by chamfered portions 18. This further reduces the deformation of the contact surface, resulting in superior performance. However, this disclosure is not limited to this method; the inner shoulder groove 17 may also have an edge where the contact surface of the land portion intersects substantially at a right angle with the groove wall extending radially along the tire.

[0050] The structure of this embodiment will now be described in more detail. Each structure described below represents a specific embodiment. Therefore, it is self-evident that the present disclosure can achieve the aforementioned effects even without the structures described below. Furthermore, even when any one of the structures described below is applied individually to the tire of the present disclosure possessing the above features, an improvement in the performance corresponding to each structure can be expected. Moreover, in the case of multiple combined applications of the structures described below, an improvement in the combined performance corresponding to each structure can be expected.

[0051] like Figure 2 As shown, among the five land portions 4 of the tread portion 2, the land portion 4 located closer to the outer tread end To has a larger axial width at the contact patch. For such a tire 1, the land portion closer to the outer tread end To has greater rigidity. Therefore, even when the center of the contact patch moves towards the outer tread end To due to steering, the steering response becomes stable, and lateral resistance is generated linearly with the increase of the steering angle. As a result, excellent handling stability and ride comfort are achieved.

[0052] Specifically, the tire axial width Wis of the contact surface of the inner shoulder land portion 11 is preferably 90% or more, and more preferably 90% to 99%, of the tire axial width Wc of the contact surface of the crown land portion 14. Similarly, the tire axial width Wim of the contact surface of the inner intermediate land portion 15 is preferably 90% to 99% of the aforementioned width Wc of the crown land portion 14.

[0053] The axial width Wom of the tire at the contact surface of the outer middle land portion 13 is preferably 101% to 107% of the aforementioned width Wc of the crown land portion 14. The axial width Wos of the tire at the contact surface of the outer shoulder land portion 12 is preferably 114% to 124% of the aforementioned width Wc of the crown land portion 14. With this embodiment of tire 1, for example, when mounted on all wheels of a vehicle, the front and rear wheels exert lateral resistance evenly, resulting in excellent initial responsiveness and handling stability.

[0054] like Figure 3 As shown, the maximum groove width W2 of the inner shoulder circumferential groove 5 is preferably 55% to 70% of the tire axial width Wis of the contact surface of the inner shoulder land portion 11. Such an inner shoulder circumferential groove 5 improves both wet performance and noise performance in a balanced way.

[0055] The inner shoulder transverse groove 16 extends at an angle of 10° or less relative to the tire axial direction, for example. Furthermore, the inner shoulder transverse groove 16, for example, crosses the center of the tire axial direction of the contact surface of the inner shoulder land portion 11. No sipes or other grooves are provided between the inner end 16a of the inner shoulder transverse groove 16 and the inner shoulder circumferential groove 5 in this embodiment. The tire axial length L3 of the inner shoulder transverse groove 16 is, for example, 70% to 85% of the width Wis of the contact surface of the inner shoulder land portion 11.

[0056] The inner shoulder groove 17 extends, for example, along the inner shoulder transverse groove 16. The angle difference between the inner shoulder groove 17 and the inner shoulder transverse groove 16 is less than 5°, and in this embodiment, they extend in parallel.

[0057] like Figure 4 As shown, the depth d1 of the inner shoulder sipe 17 is, for example, 3.0 to 5.0 mm. The chamfered portion 18 of the inner shoulder sipe 17 includes, for example, an inclined surface 18a that is inclined at an angle θ1 of 30 to 60° relative to the sipe depth direction. The depth d2 of the chamfered portion 18 is, for example, 0.5 to 2.0 mm. The width W3 of the chamfered portion 18 when viewed from above is, for example, 2.0 to 4.0 mm. Such a chamfered portion 18 reliably improves braking performance.

[0058] like Figure 3 As shown, a plurality of inner intermediate transverse grooves 19 are provided in the inner intermediate land portion 15. The inner intermediate transverse grooves 19 completely traverse the inner intermediate land portion 15 in the tire axial direction. Such inner intermediate transverse grooves 19 are beneficial to improving wet performance. However, this disclosure is not limited to this embodiment, and it is also possible for the inner intermediate land portion 15 to be provided only with sipes, as described later.

[0059] The inner intermediate transverse groove 19 extends in a straight line, for example, with a constant groove width W5. The groove width W5 of the inner intermediate transverse groove 19 is less than the maximum groove width W4 of the inner shoulder transverse groove 16 in the contact surface of the inner shoulder land portion 11, preferably 30% to 50% of the groove width W4.

[0060] The inner center transverse groove 19 is inclined relative to the tire axial direction, for example. In the figures of this specification, the inner center transverse groove 19 is inclined to the lower right; hereinafter, this inclination direction is sometimes referred to as "inclination relative to the tire axial direction in the first direction". The angle θ2 of the inner center transverse groove 19 relative to the tire axial direction is greater than the angle of the inner shoulder transverse groove 16 relative to the tire axial direction, for example, 15 to 45°. Such an inner center transverse groove 19 also provides traction in the tire axial direction when driving on wet surfaces.

[0061] The tire circumferential spacing length of the plurality of inner intermediate transverse grooves 19 is, for example, 80% to 120% of the tire circumferential spacing length of the plurality of inner shoulder grooves 17, and in a preferred embodiment they are the same.

[0062] The distance L5 in the tire circumferential direction between the end of the inner shoulder circumferential groove 19 (the end of the groove centerline of the inner shoulder circumferential groove 19) and the end of the inner shoulder circumferential groove 17 (the end of the groove centerline of the inner shoulder sipe 17) is less than 15% of the distance L4 in the tire circumferential direction from the inner shoulder circumferential groove 16 to the inner shoulder sipe 17 at the inner tread end Ti. Here, the distance L4 refers to the distance on the inner tread end Ti from the groove centerline of the inner shoulder circumferential groove 16 to the groove centerline of the inner shoulder sipe 17. This prevents the spacing noise of the inner shoulder circumferential groove 19 and the inner shoulder circumferential groove 16 from overlapping and achieves uniform ground pressure between the inner shoulder land portion 11 and the inner shoulder land portion 15.

[0063] In this embodiment, the inner middle land portion 15 and the inner shoulder land portion 11 are only provided with the aforementioned grooves and sipes, and no other grooves or sipes are provided. Therefore, the aforementioned effects are reliably achieved.

[0064] Figure 5 Enlarged views of the outer shoulder land portion 12, the outer middle land portion 13, and the crown land portion 14 are shown. Figure 5 As shown, a plurality of outer shoulder transverse grooves 30 and a plurality of outer shoulder sipes 31 are provided on the outer shoulder land portion 12. The plurality of outer shoulder transverse grooves 30 extend from the outer shoulder circumferential groove 7 to a position exceeding the outer tread end To. Furthermore, the plurality of outer shoulder sipes 31 are connected to the outer shoulder circumferential groove 7, and in this embodiment, extend from the outer shoulder circumferential groove 7 to a position exceeding the outer tread end To.

[0065] Figure 6 Show Figure 2 A BB-line sectional view. For example... Figure 5 as well as Figure 6 As shown, the multiple outer shoulder sipes 31 are respectively located at least within the range from the outer shoulder circumferential groove 7 to the outer tread end To, and the edges of the sipes on both sides are formed by chamfered portions 42.

[0066] like Figure 5 As shown, a plurality of outer intermediate groove-like portions 29 are provided on the outer intermediate land portion 13, which completely traverse the outer intermediate land portion 13 in the tire axial direction. In this specification, "groove-like portion" refers to a cutting element that includes the aforementioned cutting groove and also includes a groove with a width larger than the cutting groove. In this embodiment, the outer intermediate groove-like portion 29 is configured as an outer intermediate transverse groove 24 including two walls extending radially along the tire and the maximum distance between the two walls is greater than 1.5 mm. However, this disclosure is not limited to this manner, and as described later, the outer intermediate groove-like portion 29 may also be configured as an outer intermediate cutting groove with a maximum distance between the two walls of 1.5 mm or less. The two walls are formed at an angle of 10° or less relative to the tire radial direction, for example, to distinguish them from the inclined surface of the chamfered portion. In addition, the angle between the two walls is, for example, 15° or less.

[0067] Figure 7 An enlarged view of the outer shoulder sipe 31 and the outer middle groove 29 is shown. Figure 7 As shown, the deviation L6 in the tire circumferential direction between the inner end 31i of the outer shoulder circumferential groove 7 of the outer shoulder groove 31 and the outer end 29o of the outer shoulder circumferential groove 7 of the outer intermediate groove 29 is a tire circumferential spacing length P1 of the multiple outer shoulder grooves 31. Figure 5 As shown below (the same applies below), the percentage is less than 5%. The tire of this disclosure, by employing the above-described structure, is able to maintain wet performance and improve handling stability and braking performance. The following mechanism can be deduced as a reason for this.

[0068] like Figure 5 As shown, for the tire 1 of this embodiment, the outer shoulder lateral groove 30 and the outer middle groove 29 can provide sufficient drainage performance and maintain wet performance. On the other hand, the outer shoulder sipes 31, whose edges are formed entirely by chamfered portions 42, can suppress deformation of the contact surface of the outer shoulder land portion 12 during cornering or braking when the contact pressure acting on the outer shoulder land portion 12 increases, thereby improving handling stability and braking performance.

[0069] Furthermore, in this embodiment, since the aforementioned positional deviation L6 is specified to be less than 5% of the aforementioned pitch length P1, the chamfered portion 42 of the outer shoulder sipe 31 easily contacts the ground when the outer shoulder sipe 31 and the outer intermediate groove 29 are in contact with the ground. Additionally, according to the above structure, the outer shoulder lateral groove 30 and the outer intermediate groove 29 are offset in the tire circumferential direction, therefore, the tread blocks contained in the outer shoulder land portion 12 and the outer intermediate land portion 13 can effectively exert friction with good connectivity. Based on the above mechanism, it is presumed that wet performance can be maintained, and handling stability and braking performance can be improved.

[0070] like Figure 5 As shown, in this embodiment, the outer shoulder transverse grooves 30 and the outer shoulder sipes 31 are alternately arranged in the tire circumferential direction. Therefore, the tire circumferential spacing length P2 of the plurality of outer shoulder transverse grooves 30 is the same as the tire circumferential spacing length P1 of the outer shoulder sipes 31.

[0071] The outer shoulder lateral grooves 30 and outer shoulder sipes 31 are arranged at an angle of less than 10° relative to the tire axial direction, and in a preferred embodiment, they are arranged parallel to each other. Such outer shoulder lateral grooves 30 and outer shoulder sipes 31 are beneficial to improving braking performance.

[0072] The width of the outer shoulder lateral groove 30 continuously decreases towards the outer tread end To. As a result, for the tread blocks divided by the outer shoulder lateral groove 30, the tire circumferential length of the portion near the outer tread end To increases, thus improving handling stability.

[0073] Figure 8 Show Figure 5 A CC-line sectional view. For example... Figure 8 As shown, the outer shoulder lateral groove 30 preferably has its edge formed by a chamfered portion 32. The chamfered portion 32 includes, for example, an inclined surface 33 that is inclined at an angle of 30 to 60° relative to the radial direction of the tire. As a result, braking performance is further improved.

[0074] like Figure 5 As shown, the chamfered portion 32 of the outer shoulder transverse groove 30 preferably decreases continuously in width when viewed from above as it approaches the outer tread end To. This uniformizes the contact pressure of the outer shoulder land portion 12, further improving braking performance.

[0075] In this embodiment, according to the above-described structure, the outer shoulder transverse groove 30 is offset from the outer intermediate groove 29. Therefore, in addition to the effects described above, the suction noise of each transverse groove can be suppressed, improving noise performance. To further enhance this effect, the offset L7 in the tire circumferential direction between the inner end of the outer shoulder circumferential groove 7 side of the outer shoulder transverse groove 30 and the outer end of the outer intermediate groove 29 is preferably 30% to 50% of the tire circumferential spacing length P2 of the plurality of outer shoulder transverse grooves 30.

[0076] like Figure 6 As shown, the depth d3 of the outer shoulder sipe 31 is, for example, 3.0 to 5.0 mm. The chamfered portion 42 of the outer shoulder sipe 31 includes, for example, an inclined surface 43 that is inclined at an angle θ3 of 30 to 60° relative to the sipe depth direction. The depth d4 of the chamfered portion 42 is, for example, 0.5 to 2.0 mm. The width W6 of the chamfered portion 42 when viewed from above is, for example, 2.0 to 4.0 mm. Such a chamfered portion 18 is beneficial for reliably improving braking performance.

[0077] like Figure 5 As shown, the chamfered portion 42 of the outer shoulder groove 31 extends along the tire axial direction with a constant width. This allows it to cooperate with the chamfered portion 32 of the aforementioned outer shoulder lateral groove 30, thereby improving handling stability and braking performance under various conditions.

[0078] like Figure 7 As shown, the positional deviation L6 between the inner end 31i of the outer shoulder groove 31 and the outer end 29o of the outer middle groove 29 is preferably one of the aforementioned spacing lengths P1. Figure 5 The percentage is less than 3%, more preferably less than 1.0%. In a further preferred embodiment, the imaginary region obtained by extending the outer shoulder groove 31 along its length direction overlaps with the end of the outer tread end To side of the outer intermediate groove 29. This makes the above-mentioned effects more reliable.

[0079] like Figure 5 As shown, the outer intermediate groove 29 is arranged at the same spacing as the outer shoulder groove 31. Thus, the plurality of outer intermediate grooves 29 are respectively arranged relative to the outer shoulder groove 31 in the above-described relationship.

[0080] The outer intermediate groove 29 is inclined, for example, in a second direction opposite to the first direction (upper right in the figures of this specification) relative to the tire axial direction. The maximum angle θ4 of the outer intermediate groove 29 relative to the tire axial direction is greater than the angle of the outer shoulder lateral groove 30 or the outer shoulder sipe 31 relative to the tire axial direction. Furthermore, the maximum angle θ4 of the outer intermediate groove 29 relative to the tire axial direction is, for example, 35 to 55°. Such an outer intermediate groove 29 can provide friction evenly in both the tire circumferential and axial directions when driving on wet surfaces.

[0081] As described above, in this embodiment, the outer intermediate groove 29 is configured as an outer intermediate transverse groove 24. The outer intermediate transverse groove 24 is, for example, an S-shape including a portion 24a that curves convexly to one side of the tire circumferential direction and a portion 24b that curves convexly to the other side of the tire circumferential direction. More specifically, the outer intermediate transverse groove 24 is curved in an S-shape such that the angles relative to the tire axial direction at both ends of the outer intermediate transverse groove 24 at the two ends are smaller than the angles relative to the tire axial direction at the center of the outer intermediate transverse groove 24 at the two ends. The angles θ5 of the outer intermediate transverse groove 24 at both ends relative to the tire axial direction are, for example, 7 to 22°. Such an outer intermediate transverse groove 24 can suppress uneven wear near the two ends and improve handling stability and noise performance. However, the outer intermediate transverse groove 24 of this disclosure is not limited to the aforementioned S-shape.

[0082] In this embodiment, the outer intermediate transverse groove 24 includes, for example, a central straight portion 35 that forms the maximum angle of the outer intermediate transverse groove 24 relative to the tire axial direction and extends in a straight line. The tire axial length of the central straight portion 35 is, for example, 48% to 64% of the tire axial width WOM of the contact surface of the outer intermediate land portion 13.

[0083] In this embodiment, the outer intermediate groove 29 extends at a constant depth, for example. However, the outer intermediate groove 29 is not limited to this manner. In this specification, as another embodiment, an outer intermediate groove 29 with a depth varying in the length direction of the groove will be described later.

[0084] The center position of the tread land portion 14 in the tire axial direction is located on the outer tread end To side, which is further out than the tire equator C. The axial width Wco of the outer contact surface 14a of the tread land portion 14 is greater than the axial width Wci of the inner contact surface 14b of the tread land portion 14. Specifically, the width Wco is 51% to 55% of the axial width Wc of the contact surface of the tread land portion 14. This suppresses uneven wear of the tread land portion 14 and improves handling stability. The outer contact surface 14a refers to the contact surface of the tread land portion 14 on the outer tread end To side, which is further out than the tire equator C. The inner contact surface 14b refers to the contact surface of the tread land portion 14 on the inner tread end Ti side, which is further inward than the tire equator C.

[0085] The land portion 14 of the tire crown has a plurality of crown grooves 20 that are inclined relative to the tire axial direction. In this embodiment, the crown grooves 20 are inclined in the first direction described above, for example, relative to the tire axial direction. The angle of the crown grooves 20 relative to the tire axial direction is, for example, 15 to 45°. Such crown grooves 20 can provide friction evenly in both the circumferential and axial directions of the tire when driving on wet surfaces.

[0086] The crown sipes 20 include, for example, a plurality of outer crown sipes 21 and a plurality of inner crown sipes 22. The outer crown sipes 21 extend from the outer crown circumference toward the groove 8 and are interrupted within the crown land portion 14. The inner crown sipes 22 extend from the inner crown circumference toward the groove 6 and are interrupted within the crown land portion 14. In a more preferred embodiment, the outer crown sipes 21 and the inner crown sipes 22 are arranged parallel to each other. Such outer crown sipes 21 and inner crown sipes 22 are beneficial in suppressing uneven wear on the crown land portion 14 and the inner intermediate land portion 15.

[0087] The outer tread groove 21 and the inner tread groove 22 are preferably located at positions that do not cross the tire equator C and the center of the tire axial direction of the tread land portion 14, respectively. The axial length L8 of the tread groove 20 is, for example, 20% to 40% of the width Wc of the contact patch of the tread land portion 14.

[0088] When viewing the tire tread from above, the area obtained by extending the outer crown sipe 21 parallel to its length direction preferably overlaps with the inner crown sipe 22. This arrangement of the outer crown sipe 21 and the inner crown sipe 22 can whiten the noise between the sipes, thus improving noise performance.

[0089] The distance L9 in the tire circumferential direction between the inner end of the outer crown circumferential groove 8 side of the outer intermediate groove 29 and the outer end of the outer crown circumferential groove 8 side of the outer crown sipe 21 is preferably less than 15% of the tire circumferential spacing length P3 of the outer crown sipe 21. This makes the chamfered portion of the outer crown sipe 21 easier to contact the ground, improving braking performance.

[0090] Preferably, the edges of the sipes on both sides of the tread groove 20 are formed by chamfered portions 23. These chamfered portions 23 include chamfered portions 42 that meet the outer shoulder sipe 31. Figure 6 The same inclined surface as shown. The width and depth of the chamfered portion 23 of the tire crown groove 20 are preferably 1.0 to 3.0 mm.

[0091] In this embodiment, the outer shoulder land portion 12, the outer middle land portion 13, and the crown land portion 14 are only provided with the aforementioned grooves and sipes, and no other grooves or sipes are provided. Therefore, the aforementioned effects are reliably achieved.

[0092] Hereinafter, other embodiments of this disclosure will be described. In the figures illustrating other embodiments, the elements already described are labeled with the same reference numerals as described above, and the above structure can be applied.

[0093] Figure 9 Enlarged views of the inner shoulder land portion 11 and the inner middle land portion 15 of other embodiments are shown. Figure 9As shown, in this embodiment, a plurality of inner intermediate grooves 36 are provided in the inner intermediate land portion 15. The other land portions in this embodiment have the same structure as in the above embodiment, and their description is omitted here.

[0094] The inner center sipes 36 extend axially from the inner shoulder towards the groove 5 along the tire axis and are interrupted within the inner center land portion 15. The tire axial length L10 of the inner center sipes 36 is, for example, 30% to 70% of the aforementioned width Wim of the inner center land portion 15. Such inner center sipes 36 are beneficial for a balanced improvement in wet performance and noise performance.

[0095] The inner intermediate sipe 36 is inclined in the first direction relative to the tire axis. The angle of the inner intermediate sipe 36 relative to the tire axis is, for example, 15 to 45°.

[0096] In the inner middle sipe 36, the edges of the sipes on both sides are formed by chamfered portions. The chamfered portion 34 of the inner middle sipe 36 is similar to the chamfered portion 23 of the outer tread sipe 21 and the inner tread sipe 22. Figure 5 (As shown) is essentially the same. Furthermore, the maximum depth of the chamfered portion 34 of the inner center sipe 36 is preferably less than the maximum depth of the chamfered portion 18 of the inner shoulder sipe 17. Additionally, the maximum opening width of the inner center sipe 36 is preferably less than the maximum opening width of the inner shoulder sipe 17. Such an inner center sipe 36 can homogenize the contact pressure of the inner center land portion 15, further improving braking performance.

[0097] Hereinafter, another embodiment of the present disclosure will be described, specifically the outer intermediate groove 29. This outer intermediate groove 29 can be suitably applied to the tread surface 2 having the above-described tread pattern elements. Figure 10 An enlarged view of the outer intermediate groove 29 in another embodiment is shown. Figure 11 Showing the representation Figure 10 An enlarged three-dimensional view of the interior of the outer middle groove-shaped portion 29. (See image below.) Figure 10 as well as Figure 11 As shown, the outer intermediate groove 29 of this embodiment includes a shallow bottom 25 and a deep bottom 26 with a depth greater than the shallow bottom 25. Such an outer intermediate groove 29 is beneficial for maintaining wet performance and improving handling stability. The above-described structure can be applied to the shape of the outer intermediate groove 29 when viewed from above the tread.

[0098] Specifically, the deep bottom 26 includes: a first deep bottom 27 disposed on the outermost tread end To side of the outermost central land portion 13, relative to the center position of the tire axial direction; and a second deep bottom 28 disposed on the innermost tread end Ti side of the aforementioned central position. A shallow bottom 25 is disposed between the first deep bottom 27 and the second deep bottom 28. In addition to the aforementioned effects, this outermost central groove 29 also contributes to improved noise performance and ride comfort.

[0099] Figure 12 Show Figure 10 A DD-line sectional view. For example... Figure 12 As shown, the axial length L11 of the shallow bottom 25 is, for example, the axial width Wom of the tire at the contact surface of the outer middle land portion 13. Figure 10 As shown below, the same applies (20% to 90%, preferably 30% to 50%). In addition, the depth d5 ​​of the shallow bottom 25 is 15% to 25% of the maximum depth of the outer middle groove 29. Such a shallow bottom 25 can improve wetland performance and handling stability in a balanced way.

[0100] The tire axial length L12 of the first deep bottom 27 and the tire axial length L13 of the second deep bottom 28 are, for example, 5% to 40% of the tire axial width Wom of the contact surface of the outer intermediate land portion 13, preferably 20% to 35%. Furthermore, the tire axial length L13 of the second deep bottom 28 is preferably greater than the tire axial length L12 of the first deep bottom 27. Specifically, the aforementioned length L12 of the first deep bottom 27 is preferably 60% to 80% of the aforementioned length L13 of the second deep bottom 28. This results in excellent drainage performance in the second deep bottom 28. Wherein, when the aforementioned lengths L11 of the shallow bottom 25, L12 of the first deep bottom 27, and L13 of the second deep bottom 28 vary in the depth direction of the outer intermediate groove portion 29, their lengths are measured at the midpoint of the aforementioned depth direction.

[0101] Furthermore, the maximum depth of the second deep bottom 28 is greater than the maximum depth of the first deep bottom 27. Therefore, the maximum depth d7 of the second deep bottom 28 constitutes the maximum depth of the outer intermediate groove 29. The maximum depth d6 of the first deep bottom 27 is, for example, 60% to 75% of the maximum depth d7 of the second deep bottom 28.

[0102] Figure 13 Show Figure 10 EE line section view. Figure 14 Show Figure 10 A FF-line section view. (For example...) Figure 13 as well as Figure 14As shown, the groove walls of the deep bottom 26 include: an outer groove wall 26a connected to the groove wall 25a of the shallow bottom 25; and an inner groove wall 26b connected to the radially inner side of the outer groove wall 26a. The angle of the inner groove wall 26b relative to the tire radial direction is smaller than that of the outer groove wall 26a relative to the tire radial direction. Specifically, the angle of the outer groove wall 26a relative to the tire radial direction is, for example, 40 to 50°. The angle of the inner groove wall 26b relative to the tire radial direction is, for example, less than 10°. Such a deep bottom 26 can improve wet performance and handling stability in a balanced way.

[0103] Hereinafter, another embodiment of this disclosure will be described. The same reference numerals will be used for elements common to the embodiments described above, indicating that the above structure can be applied.

[0104] Figure 15 A development view of the tread portion 2 according to another embodiment is shown. Additionally, Figure 16 An enlarged view of the outer shoulder land portion 12 and the outer middle land portion 13 of this embodiment is shown. Figure 16 As shown, in this embodiment, the outer shoulder sipe 31 extends from the outer shoulder periphery toward the groove 7 and is interrupted within the outer shoulder land portion 12 without reaching the outer tread end To. Furthermore, in this embodiment, the outer intermediate groove portion 29 is formed as the outer intermediate sipe 45. In its cross-section, the maximum distance between the two walls of the outer intermediate sipe 45 is 1.5 mm or less.

[0105] In this embodiment, as described above, the positional deviation L6 between the inner end 31i of the outer shoulder circumferential groove 7 side of the outer shoulder groove 31 and the outer end 29o of the outer shoulder circumferential groove 7 side of the outer intermediate groove 29 in the tire circumferential direction is less than 5% of the tire circumferential spacing length P1 of the plurality of outer shoulder grooves 31. This maintains wet performance and improves handling stability and braking performance.

[0106] The axial length L14 of the outer shoulder sipe 31 is 45% to 65% of the axial width Wos of the tire at the contact surface of the outer shoulder land portion 12. Such an outer shoulder sipe 31 can improve wet performance and handling stability in a balanced way.

[0107] In the outer shoulder groove 31 of this embodiment, the edges of the grooves on both sides are formed by chamfered portions 42. Furthermore, the chamfer width of the chamfered portions 42 increases towards the outer shoulder circumferential groove 7. The maximum chamfer width of the chamfered portion 42 is, for example, 1.0 to 3.0 mm, and the maximum depth of the chamfered portion 42 is, for example, 1.0 to 3.0 mm. This uniformizes the ground pressure acting on the outer shoulder land portion 12, further improving handling stability and braking performance.

[0108] Figure 17 Show Figure 16 A cross-sectional view along the GG line. (See example.) Figure 17 As shown, the outer shoulder groove 31 of this embodiment includes: a deep bottom 31a including the end of the outer shoulder circumferential groove 7; and a shallow bottom 31b having a depth smaller than the deep bottom 31a. The depth d9 of the deep bottom 31a is, for example, 70% to 100% of the depth d8 of the outer shoulder circumferential groove 7. The depth d10 of the shallow bottom 31b is, for example, 2.0 to 4.0 mm. The tire axial length L15 of the deep bottom 31a is preferably the tire axial width Wos of the contact surface of the outer shoulder land portion 12. Figure 16 (as shown) 5% to 20%. Such outer shoulder grooves 31 are beneficial for a balanced improvement in wet performance and handling stability.

[0109] like Figure 16 As shown, in this embodiment, the outer center sipe 45 is inclined, for example, in the direction opposite to the outer shoulder sipe 31 relative to the tire axial direction. The angle of the outer center sipe 45 relative to the tire axial direction is, for example, 20 to 30°. Therefore, the outer shoulder sipe 31 and the outer center sipe 45 can provide friction in multiple directions, further improving wet performance.

[0110] In the outer intermediate sipe 45, the edges of the sipes on both sides are formed by chamfered portions 46. The chamfered portions 46 of the outer intermediate sipe 45 include, for example, a constant width portion 47, an inner widening portion 48, and an outer widening portion 49. The constant width portion 47 extends along the length of the sipe with a constant chamfer width. The inner widening portion 48 is connected, for example, to the outer circumferential groove 8 side of the constant width portion 47, and the chamfer width continuously increases from the constant width portion 47 to the outer circumferential groove 8. The outer widening portion 49 is connected, for example, to the outer shoulder circumferential groove 7 side of the constant width portion 47, and the chamfer width continuously increases from the constant width portion 47 to the outer shoulder circumferential groove 7. Such chamfered portions 46 can maintain handling stability and improve braking performance.

[0111] In a more preferred embodiment, the maximum chamfer width of the inner widening portion 48 is greater than the maximum chamfer width of the outer widening portion 49. This ensures sufficient chamfer width on the equatorial side of the tire where ground contact pressure is relatively high, thereby further enhancing the aforementioned effect.

[0112] Figure 18 Show Figure 16 A cross-sectional view along the HH line. (e.g.) Figure 18As shown, similar to the outer intermediate groove 29 described above, the outer intermediate sipe 45 includes a shallow bottom 25 and a deep bottom 26 with a depth greater than the shallow bottom 25. The deep bottom 26 includes: a first deep bottom 27 disposed on the outer tread end To side of the outer intermediate land portion 13, which is located beyond the center position of the tire axial direction; and a second deep bottom 28 disposed on the inner tread end Ti side, which is located beyond the aforementioned center position. The shallow bottom 25 is disposed between the first deep bottom 27 and the second deep bottom 28. Such an outer intermediate sipe 45 is beneficial for maintaining wet performance and improving handling stability.

[0113] The axial length L11 of the shallow bottom 25 of the tire is, for example, the axial width Wom of the tire at the contact patch of the outer middle land portion 13 (e.g.) Figure 16 As shown below (the same applies), the depth d5 ​​of the shallow bottom 25 is 60% to 90%. Additionally, the depth d5 ​​of the shallow bottom 25 is, for example, 1.0 to 3.0 mm. This shallow bottom 25 can improve wetland performance and handling stability in a balanced manner.

[0114] The tire axial length L12 of the first deep bottom 27 and the tire axial length L13 of the second deep bottom 28 are, for example, 5% to 20% of the tire axial width Wom of the contact surface of the outer middle land portion 13. Furthermore, the tire axial length L13 of the second deep bottom 28 is preferably greater than the tire axial length L12 of the first deep bottom 27. Specifically, the aforementioned length L12 of the first deep bottom 27 is preferably 60% to 75% of the aforementioned length L13 of the second deep bottom 28. This results in excellent drainage performance in the second deep bottom 28.

[0115] Furthermore, the maximum depth d6 of the first deep bottom 27 and the maximum depth d7 of the second deep bottom 28 are 70% to 100% of the maximum depth d10 of the outer shoulder circumferential groove 7. Additionally, the maximum depth d7 of the second deep bottom 28 is preferably greater than the maximum depth d6 of the first deep bottom 27. Thus, the maximum depth d7 of the second deep bottom 28 constitutes the maximum depth of the outer intermediate sipe 45. The maximum depth d6 of the first deep bottom 27 is, for example, 80% to 95% of the maximum depth d7 of the second deep bottom 28. This maintains wet performance and further improves handling stability and braking performance.

[0116] like Figure 15 As shown, in this embodiment, the inner intermediate land portion 15 is provided with a plurality of inner intermediate transverse grooves 55. The inner intermediate transverse grooves 55 completely traverse the inner intermediate land portion 15 in the tire axial direction. In a preferred embodiment, the inner intermediate transverse grooves 55 are inclined relative to the tire axial direction in the same direction as the outer intermediate groove portion 29; in a more preferred embodiment, they are arranged in parallel.

[0117] The inner central transverse sipe 55 preferably has chamfered edges on both sides. The chamfer width of the chamfered portion 56 of the inner central transverse sipe 55 increases from the center of the tire axis toward both sides of the tire axis. This further improves handling stability and braking performance.

[0118] In this embodiment, the inner shoulder land portion 11 is provided with an inner shoulder connecting groove 57 extending from the inner end 16a of the inner shoulder transverse groove 16 to the inner shoulder circumferential groove 5. Such an inner shoulder connecting groove 57 is beneficial for maintaining wet performance.

[0119] The tire of one embodiment of the present disclosure has been described in detail above, but the present disclosure is not limited to the specific embodiment described above and can be implemented in various ways.

[0120] Example

[0121] Based on the specifications in Table 1, a prototype with... Figure 1 The basic tread pattern size is 235 / 55R19 for tires. Additionally, as a benchmark tire used for comparing various performance characteristics, the width of each land portion of the tread was prototyped. Figure 1 The tires shown have the same structure but do not have grooves or sipes on their land surfaces. As a comparative example, such as... Figure 19 As shown, a tire with an inner shoulder transverse groove b and an inner shoulder sipe c provided on the inner shoulder land portion a was prototyped. In the comparative example, the inner shoulder sipe c is not connected to the inner shoulder circumferential groove d and does not include a chamfered portion. The comparative example tire, apart from the above, has the following characteristics... Figure 1 The tread patterns shown are essentially the same. Wet performance, noise levels, and braking performance of each test tire were tested. The common specifications and test methods for all test tires are as follows.

[0122] Wheel rim installation: 19×7.0J

[0123] Tire internal pressure: 230 kPa

[0124] Test vehicle: 2000cc engine, four-wheel drive vehicle

[0125] Tire mounting locations: All wheels

[0126] <Wetland Performance>

[0127] The wet performance of the test vehicles on wet roads was evaluated using the driver's senses. The results were expressed as a score of 100, with the wet performance of the comparative tires as the benchmark; a higher score indicates better wet performance.

[0128] <Noise Performance>

[0129] The test vehicle was driven on a dry road surface at speeds of 40–100 km / h, and the maximum sound pressure level inside the vehicle was measured. The difference between this sound pressure level and that of a reference tire, i.e., the reduction in sound pressure, was expressed as an exponent of 100, with the reduction in sound pressure level of the comparative example as the index. A larger exponent indicates a lower maximum sound pressure level and superior noise performance.

[0130] <Braking performance>

[0131] The braking distance of the test vehicle was measured when it was subjected to emergency braking from 100 km / h on a dry road surface. The difference between the braking distance of the test vehicle and that of the reference tire, i.e., the improvement in braking distance, was expressed as an exponent with the improvement in braking distance of the comparative example as 100. A larger exponent indicates a greater improvement in braking distance and superior braking performance.

[0132] The test results are shown in Table 1.

[0133]

[0134] The test results confirm that the tires of the embodiment maintain wet performance and improve noise and braking performance.

[0135] For reference, such as Figure 20 As shown, a prototype tire was manufactured with the following characteristics: the outer shoulder sipe f and the outer intermediate groove g are offset in the tire circumferential direction, and the inner end of the outer shoulder lateral groove e faces the outer end of the outer intermediate groove g. The tire of the reference example, except for the above-mentioned features, has the following characteristics... Figure 1 The tread patterns shown are essentially the same. In addition to the wet performance and braking performance tested above, handling stability was also tested for each test tire. The testing method for handling stability is as follows.

[0136] <Maneuverability>

[0137] The handling stability of the test vehicles on dry roads was evaluated using the driver's senses. The results were expressed as a score of 100, with the handling stability of the reference tires as the benchmark; a higher score indicates better handling stability.

[0138] The test results are shown in Table 2 below. In Table 2, the wetland performance of the embodiments is represented by a score of 100, with the wetland performance of the reference example as 100. Additionally, in Table 2, the braking performance of the embodiments is represented by an index of the braking distance improvement, with the braking distance improvement of the reference example as 100.

[0139]

[0140] The test results confirm that the tires in the embodiment maintain wet performance and improve handling stability and braking performance.

[0141] [Postscript]

[0142] This disclosure includes the following methods.

[0143] [This disclosure 1]

[0144] A tire has a tread portion indicating an orientation for installation on a vehicle. The tread portion includes: an outer tread end that becomes the outer side of the vehicle when installed on the vehicle; an inner tread end that becomes the inner side of the vehicle when installed on the vehicle; four circumferential grooves extending continuously in the tire circumferential direction between the outer tread end and the inner tread end; and five land portions divided by the four circumferential grooves. The four circumferential grooves include an inner shoulder circumferential groove disposed within the circumferential grooves closest to the inner tread end. Of the five land portions, the land portion located closest to the outer tread end has a higher contact patch with the tire surface. The wider the axial width of the tire, the more the five land portions are formed. The inner shoulder land portion, which is disposed on the outer side of the inner shoulder circumferential groove, is the smallest of the five land portions in terms of the axial width of the tire contacting the ground. The inner shoulder land portion is provided with a plurality of inner shoulder transverse grooves and a plurality of inner shoulder sipes. The inner shoulder transverse grooves extend from the inner end of the inner shoulder circumferential groove in the tire axial direction to a position beyond the inner tread end. The inner shoulder sipes extend from the inner shoulder circumferential groove to a position beyond the inner tread end.

[0145] [This disclosure 2]

[0146] In the tire described in this disclosure 1, the land portion includes a crown land portion disposed on the tire equator, and the width of the tire axial direction of the contact surface of the inner shoulder land portion is 90% or more of the width of the tire axial direction of the contact surface of the crown land portion.

[0147] [This disclosure 3]

[0148] In the tire described in this disclosure 2, the center position of the tire axial direction of the land portion of the tread is located at a position closer to the outer tread end than the tire equator.

[0149] [This disclosure 4]

[0150] In any one of the tires disclosed in this disclosure 1 to 3, the five land portions include: an inner intermediate land portion adjacent to the inner shoulder land portion via the inner shoulder circumferential groove, and a plurality of inner intermediate transverse grooves that completely traverse the inner intermediate land portion in the tire axial direction are provided in the inner intermediate land portion.

[0151] [This disclosure 5]

[0152] In the tire described in this disclosure 4, the distance in the tire circumferential direction between the end of the inner shoulder circumferential groove of the inner intermediate transverse groove and the end of the inner shoulder circumferential groove of the inner shoulder sipe is less than 15% of the distance in the tire circumferential direction from the inner shoulder transverse groove to the inner shoulder sipe at the end of the inner tread.

[0153] [This disclosure 6]

[0154] In any one of the tires disclosed in this disclosure 1 to 3, the five land portions include an inner intermediate land portion that is adjacent to the inner shoulder land portion via the inner shoulder circumferential groove. A plurality of inner intermediate sipes are provided in the inner intermediate land portion, and the inner intermediate sipes extend from the inner shoulder circumferential groove along the tire axial direction and are interrupted within the inner intermediate land portion.

[0155] [This disclosure 7]

[0156] In any one of the tires disclosed in this disclosure 1 to 3, the five land portions include an inner intermediate land portion that is adjacent to the inner shoulder land portion via the inner shoulder circumferential groove. The inner intermediate land portion is provided with a plurality of inner intermediate transverse grooves that completely traverse the inner intermediate land portion in the tire axial direction. In the inner intermediate transverse grooves, the edges of the grooves on both sides are formed by chamfering portions.

[0157] [This disclosure is 8]

[0158] In the tire described in this disclosure 7, the chamfer width of the chamfer portion of the inner middle transverse sipe increases from the center portion of the tire axis toward both sides of the tire axis.

[0159] [This disclosure is number 9]

[0160] In the tire described in disclosure 7 or 8, an inner shoulder connecting groove is provided on the land portion of the inner shoulder, extending from the inner end of the inner shoulder transverse groove to the inner shoulder circumferential groove.

[0161] [This disclosure is number 10]

[0162] In any one of the tires disclosed in this disclosure 1 to 9, the four circumferential grooves include an outer shoulder circumferential groove disposed in the circumferential grooves at the outermost tread end. The five land portions include: an outer shoulder land portion including the outer tread end; and an outer intermediate land portion adjacent to the outer shoulder land portion via the outer shoulder circumferential groove. A plurality of outer shoulder transverse grooves and a plurality of outer shoulder sipes are provided in the outer shoulder land portion. The plurality of outer shoulder transverse grooves extend from the outer shoulder circumferential grooves to positions beyond the outer tread end. The plurality of outer shoulder sipes are respectively connected to the outer tread end. The outer shoulder circumferential grooves are connected, and the aforementioned plurality of outer shoulder sipes are respectively formed such that, at least in the range from the outer shoulder circumferential groove to the outer tread end, the edges of the sipes on both sides are formed by chamfering. A plurality of outer intermediate groove-like portions are provided in the outer intermediate land portion, which completely traverse the outer intermediate land portion in the tire axial direction. The positional deviation of the inner end of the outer shoulder circumferential groove side of the outer shoulder sipe and the outer end of the outer shoulder circumferential groove side of the outer intermediate groove-like portion in the tire circumferential direction is less than 5% of the tire circumferential spacing length of the plurality of outer shoulder sipes.

[0163] [This disclosure is number 11]

[0164] In the tire described in this disclosure 10, the outer intermediate groove includes two walls extending radially along the tire, and the outer intermediate groove includes an outer intermediate sipe where the maximum distance between the two walls in its cross-section is less than 1.5 mm.

[0165] [This disclosure is number 12]

[0166] In the tire described in this disclosure 10, the aforementioned outer intermediate groove includes two walls extending radially along the tire, the aforementioned outer intermediate groove includes an outer intermediate transverse groove in which the maximum distance between the two walls in its cross-section exceeds 1.5 mm, the aforementioned outer intermediate transverse groove is S-shaped and includes a portion that curves convexly to one side of the tire circumferential direction and a portion that curves convexly to the other side of the tire circumferential direction.

[0167] [This disclosure is number 13]

[0168] In any one of the tires disclosed in 10 to 12, the outer intermediate groove portion includes a shallow bottom and a deep bottom with a depth greater than the shallow bottom. The deep bottom includes: a first deep bottom disposed on the outer intermediate land portion near the outer tread end side at a position greater than the center of the tire axial direction; and a second deep bottom disposed on the inner tread end side at a position greater than the center of the tire. The shallow bottom is disposed between the first deep bottom and the second deep bottom.

[0169] [This disclosure 14]

[0170] In any one of the tires disclosed in this disclosure 10 to 13, the edge of the groove in the outer shoulder transverse groove is formed by a chamfer, the outer shoulder sipe does not reach the outer tread end but is interrupted in the land portion of the outer shoulder, and the outer shoulder sipe includes: a deep bottom including the end of the outer shoulder circumferential groove side; and a shallow bottom having a depth smaller than the deep bottom.

[0171] [This disclosure is 15]

[0172] In the tire described in this disclosure 1, the five land portions include: a crown land portion disposed on the tire equator; and an inner intermediate land portion adjacent to the inner shoulder land portion via the inner shoulder circumferential groove, wherein the tire axial width of the contact surface of the inner shoulder land portion is 90% or more of the tire axial width of the contact surface of the crown land portion, and the center position of the crown land portion in the tire axial direction is located at a position closer to the outer tread end side than the tire equator. A plurality of inner intermediate transverse sipes are provided in the inner intermediate land portion, which completely transversely cross the inner intermediate land portion in the tire axial direction. In the inner intermediate transverse sipes, the edges of the sipes on both sides are formed by chamfering portions.

[0173] [This disclosure is number 16]

[0174] In the tire described in this disclosure 15, an inner shoulder connecting groove is provided on the land portion of the inner shoulder, extending from the inner end of the inner shoulder transverse groove to the inner shoulder circumferential groove.

[0175] [This disclosure is number 17]

[0176] In the tire described in this disclosure 1, the four circumferential grooves include an outer shoulder circumferential groove disposed in the circumferential grooves closest to the outermost tread end. The five land portions include: an outer shoulder land portion including the outer tread end; and an outer intermediate land portion adjacent to the outer shoulder land portion via the outer shoulder circumferential groove. A plurality of outer shoulder transverse grooves and a plurality of outer shoulder sipes are provided in the outer shoulder land portion. The plurality of outer shoulder transverse grooves extend from the outer shoulder circumferential grooves to positions beyond the outer tread end. The plurality of outer shoulder sipes communicate with the outer shoulder circumferential grooves. The plurality of outer shoulder sipes are formed such that, at least from the outer shoulder circumferential groove... Within the range from the groove to the outer tread end, the edges of the sipes on both sides are formed by chamfering. A plurality of outer intermediate grooves are provided in the outer intermediate land portion, which completely traverse the outer intermediate land portion in the tire axial direction. The deviation of the inner end of the outer shoulder circumferential groove side of the outer shoulder sipe and the outer end of the outer shoulder circumferential groove side of the outer intermediate groove in the tire circumferential direction is less than 5% of the tire circumferential spacing length of the plurality of outer shoulder sipes. The outer intermediate groove includes two walls extending radially along the tire. The outer intermediate groove includes an outer intermediate sipe with a maximum distance of less than 1.5 mm between the two walls in its cross-section.

[0177] [This disclosure is number 18]

[0178] In the tire described in this disclosure 17, the outer intermediate groove portion includes a shallow bottom and a deep bottom with a depth greater than the shallow bottom. The deep bottom includes: a first deep bottom disposed on the outer intermediate land portion near the outer tread end side at a position greater than the center of the tire axial direction; and a second deep bottom disposed on the inner tread end side at a position greater than the center of the tire. The shallow bottom is disposed between the first deep bottom and the second deep bottom.

[0179] [This disclosure 19]

[0180] In the tire described in this disclosure 1, the four circumferential grooves include an outer shoulder circumferential groove disposed in the circumferential grooves closest to the outermost tread end. The five land portions include: an outer shoulder land portion including the outer tread end; and an outer intermediate land portion adjacent to the outer shoulder land portion via the outer shoulder circumferential groove. A plurality of outer shoulder transverse grooves and a plurality of outer shoulder sipes are provided in the outer shoulder land portion. The plurality of outer shoulder transverse grooves extend from the outer shoulder circumferential grooves to positions beyond the outer tread end. The plurality of outer shoulder sipes communicate with the outer shoulder circumferential grooves. Each outer shoulder sipe is formed such that, at least within the range from the outer shoulder circumferential groove to the outer tread end, the edges of the sipes on both sides are formed by chamfering. Multiple outer intermediate grooves are provided on the outer intermediate land portion, completely traversing the outer intermediate land portion in the tire axial direction. The deviation in tire circumferential direction between the inner end of the outer shoulder circumferential groove side of the outer shoulder sipe and the outer end of the outer intermediate groove side of the outer shoulder circumferential groove is less than 5% of the tire circumferential spacing length of the multiple outer shoulder sipes. In the outer shoulder transverse groove, the edge of the groove is formed by chamfering.

Claims

1. A tire having a tread portion with a specified orientation for mounting on a vehicle, characterized in that, The tread portion has: an outer tread end that becomes the outer side of the vehicle when mounted on a vehicle, and an inner tread end that becomes the inner side of the vehicle when mounted on a vehicle. The tread portion has four circumferential grooves that extend continuously along the tire's circumference. The tread area is divided into 5 land sections by the 4 circumferential grooves. The four circumferential grooves include: The inner shoulder circumferential groove located on the innermost end of the tire tread; and The outer shoulder circumferential groove, located on the outermost end of the tire tread, The five land-based departments include: The inner shoulder land portion located on the outer side of the tire axial direction of the inner shoulder circumferential groove; The inner middle land portion adjacent to the inner shoulder land portion; Including the outer shoulder land portion at the outer tread end; The outer middle land portion adjacent to the outer shoulder land portion; and The crown land portion located between the inner middle land portion and the outer middle land portion. Of the five land sections, the land section located further to the outer tread end has a larger axial width in contact with the ground. Multiple inner shoulder transverse grooves and multiple inner shoulder sipes are provided on the inner shoulder land portion. Multiple outer shoulder transverse grooves and multiple outer shoulder sipes are provided on the outer shoulder land portion. The outer intermediate land portion is provided with a plurality of outer intermediate groove-shaped portions that completely traverse the outer intermediate land portion in the tire axial direction. The inner shoulder transverse grooves each have an inner end that is spaced apart from the inner shoulder circumferential groove in the tire axial direction, and extend from the inner end to a position beyond the inner tread end. The inner shoulder grooves extend from the inner shoulder circumferential groove to a position beyond the inner tread end. The outer shoulder transverse grooves extend from the outer shoulder circumferential groove to a position beyond the outer tread end. The outer shoulder grooves are connected to the outer shoulder circumferential grooves. The positional deviation in the tire circumferential direction between the inner end of the outer shoulder circumferential groove side of the outer shoulder sipe and the outer end of the outer shoulder circumferential groove side of the outer intermediate groove portion is less than 5% of a spacing length of the outer shoulder sipe in the tire circumferential direction. The outer intermediate groove portion has two walls extending radially along the tire, and includes an outer intermediate sipe portion in its cross-section where the maximum distance between the two walls is less than 1.5 mm. The outer shoulder sipes, at least within the range from the outer shoulder circumferential groove to the outer tread end, have chamfered edges on both sides. The outer shoulder grooves have chamfered edges on both sides.

2. The tire according to claim 1, characterized in that, The axial width of the inner shoulder land surface is more than 90% of the axial width of the crown land surface.

3. The tire according to claim 2, characterized in that, The center of the tire's axial direction on the land portion of the tread is located at a position closer to the outer tread end than the tire equator.

4. The tire according to claim 1, characterized in that, Multiple inner intermediate transverse grooves are provided on the inner intermediate land portion, which completely traverse the inner intermediate land portion in the tire axial direction.

5. The tire according to claim 4, characterized in that, The distance in the tire circumferential direction between the end of the inner shoulder circumferential groove of the inner intermediate transverse groove and the end of the inner shoulder circumferential groove of the inner shoulder sipe is less than 15% of the distance in the tire circumferential direction from the inner shoulder transverse groove to the inner shoulder sipe at the inner tread end.

6. The tire according to claim 1 or 2, characterized in that, A plurality of inner intermediate grooves are provided in the inner intermediate land portion. The inner intermediate grooves extend from the inner shoulder circumferential groove along the tire axial direction and are interrupted in the inner intermediate land portion.

7. The tire according to claim 1 or 2, characterized in that, The inner middle land portion is provided with a plurality of inner middle transverse cutter grooves that completely traverse the inner middle land portion in the tire axial direction. In each of the transverse cutting grooves in the middle of the inner side, the edges of the cutting grooves on both sides are formed by chamfering.

8. The tire according to claim 7, characterized in that, The chamfer width of the chamfered portion of the inner middle transverse groove increases as it moves from the center portion of the tire axis toward both sides of the tire axis.

9. The tire according to claim 7, characterized in that, An inner shoulder connecting groove is provided on the land portion of the inner shoulder, extending from the inner end of the inner shoulder transverse groove to the inner shoulder circumferential groove.

10. The tire according to claim 1, characterized in that, The outer intermediate groove includes an outer intermediate transverse groove in its cross-section where the maximum distance between the two walls exceeds 1.5 mm. The outer middle transverse groove is S-shaped, including a portion that curves convexly to one side of the tire circumference and a portion that curves convexly to the other side of the tire circumference.

11. The tire according to claim 1, characterized in that, The outer intermediate groove includes a shallow bottom and a deep bottom that is deeper than the shallow bottom. The deep bottom includes: a first deep bottom disposed on the outer middle land portion near the outer tread end side at a position relative to the tire's axial center; and a second deep bottom disposed on the inner tread end side near the center position. The shallow bottom is located between the first deep bottom and the second deep bottom.

12. The tire according to claim 1, characterized in that, The outer shoulder groove does not reach the outer tread end but is interrupted within the outer shoulder land portion. The outer shoulder groove includes: a deep bottom including the end of the outer shoulder circumferential groove side; and a shallow bottom having a depth smaller than the deep bottom.

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