Tire

Abstract

A tire is provided that improves handling stability on a dry road surface. The tire has a tread portion (2) that is oriented in a prescribed direction of assembly to a vehicle. A land portion (4) of the tread portion (2) includes a crown land portion (13), a first intermediate land portion (12), and a second intermediate land portion (14). In a 50% load applied state in which a regular rim is assembled to a regular inner pressure and a regular load is applied at 50%, and in which the tire is ground at a camber angle of 0°, when the widths of the land surfaces in the tire axial direction of the first intermediate land portion (12), the crown land portion (13), and the second intermediate land portion (14) are respectively set as W1m, Wc, W2m, the following formula (1) is satisfied. When the widths of the outer land surface (36) and the inner land surface (37) of the crown land portion (13) in the tire axial direction are respectively set as Wco, Wci, the following formula (2) is satisfied. W1m > Wc > W2m … (1) Wco > Wci … (2).

Description

Technical Field

[0001] This disclosure relates to tires. Background Technology

[0002] Patent Document 1 describes a pneumatic tire with a tread portion divided into a crown land section and a pair of intermediate land sections. The crown land section and the intermediate land sections are each formed as ribs extending continuously in the tire circumferential direction. This feature helps suppress noise during driving.

[0003] Patent Document 1: Japanese Patent Application Publication No. 2010-132181

[0004] The tread land area and center land area of ​​a tire exert significant contact pressure not only during straight-line driving but also during cornering, thus contributing greatly to handling stability on dry roads. By re-examining the structure of these land areas, the developers discovered ways to further improve these performance characteristics, thereby completing this disclosure. Summary of the Invention

[0005] This disclosure was made in view of the problems mentioned above, and the main objective is to provide a tire that improves handling stability on dry roads.

[0006] This disclosure relates to a tire having a tread portion with a specified orientation for mounting to a vehicle. The tread portion includes: a first tread end that becomes the outer side of the vehicle when mounted; a second tread end that becomes the inner side of the vehicle when mounted; a plurality of circumferential grooves extending continuously in the tire circumferential direction between the first tread end and the second tread end; and a plurality of land portions divided by the circumferential grooves. The plurality of land portions includes: a crown land portion disposed on the tire equator; a first intermediate land portion adjacent to the first tread end side of the crown land portion; and a second intermediate land portion adjacent to the second tread end side of the crown land portion. When the rim is assembled with a standard load and a 50% load with a camber angle of 0° on the ground plane, and the widths of the contact surfaces of the first intermediate land portion, the crown land portion, and the second intermediate land portion in the tire axial direction are set to W1m, Wc, and W2m respectively, the following equation (1) is satisfied. The crown land portion includes an outer contact surface that is closer to the first tread end than the tire equator and an inner contact surface that is closer to the second tread end than the tire equator. When the widths of the outer contact surface and the inner contact surface in the tire axial direction are set to Wco and Wci respectively, the following equation (2) is satisfied.

[0007] W1m>Wc>W2m…(1)

[0008] Wco>Wci…(2)

[0009] The tire disclosed herein, by employing the above-described structure, can improve handling stability on dry roads. Attached Figure Description

[0010] Figure 1 This is a unfolded view of the tread portion of an embodiment of the present disclosure.

[0011] Figure 2 It is an enlarged view showing the shape of the contact patch when the tire tread touches the ground.

[0012] Figure 3 yes Figure 1 Enlarged view of the first shoulder land area and the first intermediate land area.

[0013] Figure 4 yes Figure 3 A sectional view along line AA.

[0014] Figure 5 yes Figure 3 CC-line sectional view.

[0015] Figure 6 yes Figure 3 BB line section view.

[0016] Figure 7 yes Figure 3 DD-line sectional view.

[0017] Figure 8 yes Figure 1 Enlarged views of the first intermediate landmass, the crown landmass, and the second intermediate landmass.

[0018] Figure 9 yes Figure 1 Enlarged view of the shoulder land area of ​​the second fetus.

[0019] Figure 10 yes Figure 9 EE line section view.

[0020] Figure 11 yes Figure 1 FF line section view.

[0021] Figure 12 yes Figure 1 GG line sectional view.

[0022] Figure 13 This is an enlarged view of the first intermediate land portion of another embodiment.

[0023] Figure 14 This is an enlarged view of the first intermediate land portion of another embodiment.

[0024] Figure 15This is an enlarged view of the sidewall surface of the first tire shoulder land portion in another embodiment.

[0025] Figure 16 This is an enlarged view of the sidewall surface of the second tire shoulder land portion in another embodiment.

[0026] Figure 17 This is a unfolded view of the tread area in other embodiments.

[0027] Figure 18 yes Figure 17 A cross-sectional view of the cutting groove in the embodiment shown.

[0028] Figure 19 This is a unfolded diagram of the tread of a reference tire.

[0029] Figure 20 This is a unfolded diagram of the tread of a comparative example tire.

[0030] Explanation of reference numerals in the attached figures

[0031] 2...tread portion; 3...circumferential groove; 4...land portion; 12...first intermediate land portion; 13...crown land portion; 14...second intermediate land portion; 36...outer ground contact; 37...inner ground contact; T1...first tread end; T2...second tread end. Detailed Implementation

[0032] Hereinafter, one 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 in a pneumatic tire for passenger cars. However, the present disclosure is not limited to this method and can also be applied to pneumatic tires for heavy loads or non-pneumatic tires whose interior is not filled with pressurized air.

[0033] like Figure 1 As shown, the tire 1 of this disclosure has a tread portion 2 with a specified orientation for mounting to a vehicle. The tread portion 2 has a first tread end T1 located on the outer side of the vehicle when the tire 1 is mounted to the vehicle, and a second tread end T2 located on the inner side of the vehicle when mounted to the vehicle. The orientation for mounting to the vehicle is indicated, for example, by text or symbols on the sidewall portion (illustrations omitted).

[0034] The first tread end T1 and the second tread end T2 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° in the normal state.

[0035] "Standard condition" in the context of specified pneumatic tire sizes refers to the condition where the tire is assembled onto a standard rim, inflated to the standard 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.

[0036] "Standard rim" refers to a rim that is specified 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".

[0037] "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 "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 "INFLATION PRESSURE".

[0038] "Regular load" in the context of various specifications for pneumatic tires refers to the load specified for each tire within the specification system, including the specifications the tire is based on. For JATMA, it is "maximum load capacity"; for TRA, it is the maximum value recorded in "TIRE LOAD LIMITS AT VARIOUS COLD INFLATION PRESSURES"; and for ETRTO, it is "LOAD CAPACITY". Furthermore, in the case of tires without specified specifications, or non-pneumatic tires, "regular load" refers to the load acting on a tire in its standard assembly condition. The aforementioned "standard assembly condition" refers to the tire being mounted on a standard vehicle corresponding to the tire's intended use, and the vehicle being stationary on a flat road surface in a drivable condition.

[0039] The tread portion 2 has a plurality of circumferential grooves 3 extending continuously along the tire circumference between the first tread end T1 and the second tread end T2, and a plurality of land portions 4 divided by the circumferential grooves. The tire 1 of this embodiment is configured as a so-called 5-rib tire with the tread portion 2 including 5 land portions 4 divided by 4 circumferential grooves 3.

[0040] The circumferential groove 3 includes, for example, a first shoulder circumferential groove 5, a second shoulder circumferential groove 8, a first crown circumferential groove 6, and a second crown circumferential groove 7. The first shoulder circumferential groove 5 is located between the first tread end T1 and the tire equator C. The second shoulder circumferential groove 8 is located between the second tread end T2 and the tire equator C. The first crown circumferential groove 6 is located between the first shoulder circumferential groove 5 and the tire equator C. The second crown circumferential groove 7 is located between the second shoulder circumferential groove 8 and the tire equator C.

[0041] The tire axial distance L1 from the tire equator C to the center line of the groove of the first shoulder circumferential groove 5 or the second shoulder circumferential groove 8 is preferably 25% to 35% of the tread width TW. The tire axial distance L2 from the tire equator C to the center line of the groove of the first crown circumferential groove 6 or the second crown circumferential groove 7 is preferably 5% to 15% of the tread width TW. Here, the tread width TW refers to the tire axial distance from the first tread end T1 to the second tread end T2 in the above-described normal state.

[0042] 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 wavy shape, for example.

[0043] The groove width W1 of each circumferential groove 3 is preferably 2.0% to 8.0% of the tread width TW. In this embodiment, the first shoulder circumferential groove 5 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 preferably 5 to 10 mm, for example.

[0044] The land portion 4 disclosed herein includes a crown land portion 13, a first intermediate land portion 12, and a second intermediate land portion 14. The crown land portion 13 is disposed on the tire equator C and is divided between the first crown circumferential groove 6 and the second crown circumferential groove 7. The first intermediate land portion 12 is adjacent to the first tread end T1 side of the crown land portion 13 and is divided by the first shoulder circumferential groove 5 and the first crown circumferential groove 6. The second intermediate land portion 14 is adjacent to the second tread end T2 side of the crown land portion 13 and is divided by the second shoulder circumferential groove 8 and the second crown circumferential groove 7.

[0045] The land portion 4 in this embodiment also includes a first shoulder land portion 11 and a second shoulder land portion 15. The first shoulder land portion 11 includes a first tread end T1 and is adjacent to the first tread end T1 side of the first intermediate land portion 12. The second shoulder land portion 15 includes a second tread end T2 and is adjacent to the second tread end T2 side of the second intermediate land portion 14.

[0046] Figure 2 An enlarged view showing the shape of the contact patch when the tread portion 2 touches the ground is displayed. (See diagram below.) Figure 2As shown, when the tire is assembled on a regular rim with regular internal pressure and loaded with 50% of the regular load and grounded on the plane with a 0° camber angle, and the widths of the contact surfaces of the first shoulder land portion 11, the first intermediate land portion 12, the crown land portion 13, the second intermediate land portion 14, and the second shoulder land portion 15 are set to W1s, W1m, Wc, W2m, and W2s respectively, the following equation (1) is satisfied.

[0047] W1m>Wc>W2m…(1)

[0048] like Figure 1 As shown, the land portion 13 of the tire crown includes an outer contact surface 36 on the side closer to the first tread end T1 than the tire equator C, and an inner contact surface 37 on the side closer to the second tread end than the tire equator C. In this disclosure, when the axial widths of the outer contact surface 36 and the inner contact surface 37 are set as Wco and Wci respectively, the following equation (2) is satisfied.

[0049] Wco>Wci…(2)

[0050] In this disclosure, by adopting the above-described structure, it is possible to ensure various tire performance characteristics, such as wet performance, and improve handling stability on dry roads. The following mechanism is hypothesized as a reason for this.

[0051] With the above structure, the rigidity of each land portion of the tread portion 2 of the tire 1 of this disclosure increases towards the outer side of the vehicle. As a result, the lateral force increases linearly with the increase of the rudder angle, thereby improving handling stability on dry roads. In particular, since the land portion 13 of the tread satisfies the above equation (2), the above-mentioned effect is reliably achieved. Based on the above mechanism, the tire of this disclosure is expected to improve handling stability on dry roads.

[0052] The structure of this embodiment will now be described in more detail. The structures described below illustrate specific aspects of this embodiment. Therefore, it is self-evident that the above-described effects can be achieved even without the structures described below. Furthermore, even when any one of the structures described below is applied individually to the tire of this disclosure having the above-described features, an improvement in the performance corresponding to each structure can be expected. Moreover, when several of the structures described below are applied in combination, an improvement in the combined performance corresponding to each structure can be expected.

[0053] The tire 1 of this embodiment preferably satisfies the following equation (3) under a 50% load condition. The land portion of such a tire 1 near the first tread end T1 has greater rigidity. Therefore, even when the center of the contact patch moves towards the first tread end T1 through steering operations, the steering feel remains stable, and lateral force is generated linearly with the increase of the rudder angle. Therefore, the tire 1 of this embodiment can further improve handling stability on dry roads (hereinafter, sometimes simply referred to as "handling stability").

[0054] W1s>W1m>Wc>W2m≥W2s…(3)

[0055] Under 50% load conditions, the tire axial width W1s of the contact surface of the first shoulder land portion 11 is preferably 115% to 125% of the tire axial width Wc of the crown land portion 13. As a result, the rigidity of the first shoulder land portion 11 is optimized, and the aforementioned effects and noise performance can be improved.

[0056] From the same point of view, under a 50% load condition, the tire axial width W1m of the contact surface of the first intermediate land portion 12 is preferably 101% to 107% of the tire axial width Wc of the contact surface of the crown land portion 13.

[0057] Under 50% load conditions, the tire axial width W2m of the contact patch of the second intermediate land portion 14 is preferably 90% to 99% of the tire axial width Wc of the contact patch of the crown land portion 13. This improves noise performance during straight-line driving. Furthermore, tire vibrations during straight-line driving are less likely to be transmitted to the sides of the vehicle body, thus improving ride comfort.

[0058] From the same point of view, under a 50% load condition, the tire axial width W2s of the contact surface of the second shoulder land portion 15 is preferably 90% to 99% of the tire axial width Wc of the contact surface of the crown land portion 13.

[0059] As a more preferred embodiment, in this embodiment, under a 50% load condition, the width W2m of the second intermediate land portion 14 is the same as the width W2s of the second shoulder land portion 15. Therefore, the wear progression of the second intermediate land portion 14 and the second shoulder land portion 15 becomes more uniform, and the resistance to uneven wear is improved.

[0060] like Figure 1As shown, each land portion 4 in the embodiment is provided with a cutting groove 16. In this specification, "cutting groove" refers to a grooving element with a small width, and the width between the two groove walls at the main body portion of the cutting groove 16 is 1.5 mm or less. The width of the cutting groove 16 is preferably 0.2 to 1.2 mm, more preferably 0.5 to 1.0 mm. The cutting groove 16 may also include a wide portion with an opening wider than the above width, or a flask-shaped bottom with a width wider than the above width.

[0061] Figure 3 An enlarged view of the first shoulder land portion 11 and the first intermediate land portion 12 is shown. Figure 3 As shown, only a sipe is provided on the first shoulder land portion 11. This increases the rigidity of the first shoulder land portion 11. In this embodiment, a plurality of first shoulder sipes 21 extending along the tire axial direction are provided on the first shoulder land portion 11.

[0062] The circumferential pitch length P1 of the first shoulder sipe 21 is, for example, 100% to 130% of the tread width W3 of the first shoulder land portion 11 in the tire axial direction. Furthermore, the circumferential pitch length of both sipes refers to the distance parallel to the tire circumferential direction from the center position in the width direction of the cross-section of one sipe to the aforementioned center position of the other sipe. Additionally, when the aforementioned distance varies in the tire axial direction, the intermediate distance corresponds to the aforementioned pitch length.

[0063] Preferably, the first shoulder groove 21 communicates at least with the first shoulder circumferential groove 5. In this embodiment, the first shoulder groove 21 extends, for example, from the first shoulder circumferential groove 5 to the first tread end T1 and completely traverses the tread surface of the first shoulder land portion 11. However, the first shoulder groove 21 is not limited to this manner and may also have an interrupted end within the first shoulder land portion 11.

[0064] The first shoulder groove 21 is inclined in a first direction (upper right in the figures of this specification) relative to the tire axial direction. The angle of the first shoulder groove 21 relative to the tire axial direction is, for example, 5 to 35°. In a more preferred embodiment, the first shoulder groove 21 includes a portion whose angle relative to the tire axial direction increases as it moves toward the second tread end T2 side. Such a first shoulder groove 21 can also exert friction in the tire axial direction.

[0065] The opening width W4 of the first shoulder sipe 21 at the tread surface is, for example, greater than the opening width W5 of the first intermediate sipe 30 at the tread surface. Specifically, the opening width W4 of the first shoulder sipe 21 is, for example, 4.0 to 8.0 mm. The opening width W5 of the first intermediate sipe 30 is, for example, 2.0 to 6.0 mm. Furthermore, the opening width W5 of the first intermediate sipe 30 is 50% to 90% of the opening width W4 of the first shoulder sipe 21. Such a first shoulder sipe 21 and first intermediate sipe 30 can improve resistance to eccentric wear.

[0066] Figure 4 A diagram showing a cross-section of the first shoulder groove 21 is provided. Figure 3 A sectional view along line AA. (e.g.) Figure 4 As shown, the first shoulder groove 21 includes a main body portion 21a extending radially along the tire, and a wide portion 21b that opens at the tread surface of the land portion and has a width larger than that of the main body portion 21a. In this embodiment, the width of the main body portion is, for example, 0.5 to 1.5 mm.

[0067] The wide portion 21b of the first shoulder sipe 21 includes an inclined surface 22 extending from the main body portion 21a toward the tread. In this embodiment, the inclined surface 22 is planar and inclined at an angle θ1 of 50 to 70° relative to the tire radial direction. Because this wide portion 21b allows the entire surface of the inclined surface 22 to contact the ground when a large ground pressure is applied to the land portion, the substantial ground contact area of ​​the tread can be reliably increased. Therefore, handling stability is further improved.

[0068] The depth d1 of the wide portion 21b of the first shoulder sipe 21 is 10% to 30% of the maximum depth d3 of the first shoulder sipe 21, and preferably 0.5 to 2.0 mm. The maximum depth d3 of the first shoulder sipe 21 is, for example, 70% to 100% of the depth of the circumferential groove 3.

[0069] The width W6 (width along the tread surface in the cross-section of the sipe 21) of the wide portion 21b of the first shoulder sipe 21 is, for example, 2.0 to 4.0 mm.

[0070] Figure 5 Show Figure 3 A CC-line sectional view. For example... Figure 5 As shown, the first shoulder groove 21 includes a shallow bottom 23 with a partially raised bottom. In this embodiment, the shallow bottom 23 is provided, for example, in a connecting portion communicating with the circumferential groove 5 of the first shoulder. The minimum depth d4 of the shallow bottom 23 of the first shoulder groove 21 is 40% to 60% of the maximum depth d3 of the first shoulder groove 21. The tire axial length L3 of the shallow bottom 23 is equal to the tire axial width W3 of the land portion 11 of the first shoulder. Figure 3(as shown) 10% to 30%. The aforementioned length L3 of the shallow bottom 23 is, for example, measured at the center position in the height direction of the shallow bottom 23. The first shoulder groove 21 having such a shallow bottom 23 maintains the rigidity of the first shoulder land portion 11, thereby improving handling stability.

[0071] like Figure 3 As shown, the first intermediate land portion 12 includes a first longitudinal edge 12a on the side of the first tread end T1, a second longitudinal edge 12b on the side of the second tread end T2, and a tread surface between the first longitudinal edge 12a and the second longitudinal edge 12b. Furthermore, the first intermediate land portion 12 is only provided with sipes. This increases the rigidity of the first intermediate land portion 12. In this embodiment, the first intermediate land portion 12 is provided with a plurality of first intermediate sipes 30 extending along the tire axial direction.

[0072] Figure 6 This is shown as a cross-section of the first intermediate tool groove 30. Figure 3 A BB-line sectional view. For example... Figure 6 As shown, the first intermediate groove 30 includes a main body portion 30a extending radially along the tire and a wide portion 30b that opens at the tread surface of the land portion and has a width larger than that of the main body portion 30a. In this embodiment, the width of the main body portion is, for example, 0.5 to 1.5 mm.

[0073] The wide portion 30b of the first intermediate groove 30 includes an inclined surface 25 extending from the main body portion 30a toward the tread surface. In this embodiment, the inclined surface 25 is planar and inclined at an angle θ2 of 30 to 60° relative to the radial direction of the tire.

[0074] The depth d2 of the wide portion 30b of the first intermediate sipe 30 is 15% to 30% of the maximum depth d5 ​​of the first intermediate sipe 30. Furthermore, the depth d2 of the wide portion 30b of the first intermediate sipe 30 is, for example, 1.0 to 3.0 mm. In a more preferred embodiment, the depth d1 of the wide portion 21b of the first shoulder sipe 21 is... Figure 4 The depth d2 of the width portion 30b of the first intermediate sipe 30 is less than that of the width portion 30b of the first shoulder sipe 30. The depth d1 of the width portion 21b of the first shoulder sipe 21 is 50% to 90% of the depth d2 of the width portion 30b of the first intermediate sipe 30, preferably 60% to 80%.

[0075] The width W8 (width along the tread surface in the cross-section of the first intermediate cutter groove 30) of the wide portion 30b is, for example, 1.0 to 3.0 mm.

[0076] like Figure 3As shown, the first intermediate cutting groove 30 includes an outer first intermediate cutting groove 31 extending from the first longitudinal edge 12a and having an interrupted end 31a in the first intermediate land portion 12; and an inner first intermediate cutting groove 32 extending from the second longitudinal edge 12b and having an interrupted end 32a in the first intermediate land portion 12.

[0077] When viewed from above, the first intermediate sipe 30 extends in a straight line. Furthermore, the first intermediate sipe 30 is inclined in a first direction relative to the tire axial direction. More specifically, when viewed from above, the outer first intermediate sipe 31 and the inner first intermediate sipe 32 extend in a straight line and are inclined in a first direction relative to the tire axial direction.

[0078] The angle of the outer first intermediate sipe 31 relative to the tire axial direction and the angle of the inner first intermediate sipe 32 relative to the tire axial direction are preferably 20° or more, more preferably 25° or more, more preferably 45° or less, and more preferably 40° or less. Such outer first intermediate sipe 31 and inner first intermediate sipe 32 provide frictional force evenly in both the tire axial and tire circumferential directions.

[0079] The angle difference between the outer first intermediate cutting groove 31 and the inner first intermediate cutting groove 32 is preferably 10° or less, more preferably 5° or less, and in this embodiment they are arranged in parallel. Such outer first intermediate cutting groove 31 and inner first intermediate cutting groove 32 can suppress uneven wear of the first intermediate land portion 12.

[0080] Both the outer first intermediate sipe 31 and the inner first intermediate sipe 32 do not traverse the center of the tire axial direction of the first intermediate land portion 12, but are interrupted. The tire axial length La of the outer first intermediate sipe 31 is 20% or more, more preferably 25% or more, more preferably 45% or less, and more preferably 40% or less of the tire axial width W7 of the first intermediate land portion 12. Similarly, the tire axial length Lc of the inner first intermediate sipe 32 is 20% or more, more preferably 25% or more, more preferably 45% or less, and more preferably 40% or less of the tire axial width W7 of the first intermediate land portion 12. Such outer first intermediate sipe 31 and inner first intermediate sipe 32 can maintain handling stability and improve ride comfort and noise performance.

[0081] Preferably, the outer first intermediate sipe 31 and the inner first intermediate sipe 32 are misaligned in the tire circumferential direction. Therefore, in this embodiment, when viewed from above, the imaginary area formed by extending the outer first intermediate sipe 31 parallel to the tire axial direction does not overlap with the inner first intermediate sipe 32. Furthermore, the interrupted ends 31a of the outer first intermediate sipe 31 and 32a of the inner first intermediate sipe 32 are misaligned in the tire circumferential direction. The tire circumferential distance Lb between the interrupted ends 31a of the outer first intermediate sipe 31 and 32a of the inner first intermediate sipe 32 is, for example, less than 50% of the tire circumferential pitch length P2 of the first intermediate sipe 30, preferably 25% to 40%. In a more preferred embodiment, the distance Lb is within the range of the following formula (4). Therefore, the pitch sound of each sipe is easily converted to white noise, improving noise performance.

[0082] Lb=2La±1(mm)…(4)

[0083] In this embodiment, the pitch length P2 of the first intermediate sipe 30 is, for example, 80% to 120% of the pitch length P1 of the first shoulder sipe 21, and in a more preferred embodiment, they are the same.

[0084] In this embodiment, the outer first intermediate sipe 31 communicates with the first shoulder circumferential groove 5. Furthermore, when viewed from above, the wide portion of the outer first intermediate sipe 31 overlaps with the area formed by extending the wide portion 21b of the first shoulder sipe 21 along its length. Thus, the outer first intermediate sipe 31 and the first shoulder sipe 21 work together to further improve wet performance.

[0085] The first intermediate cutting groove 30 has a certain depth in its length direction. More specifically, the outer first intermediate cutting groove 31 and the inner first intermediate cutting groove 32 each have a certain depth in their length direction. The depth of the inner first intermediate cutting groove 32 is, for example, 70% to 100% of the depth of the circumferential groove 3. In addition, the maximum depth of the outer first intermediate cutting groove 31 is less than the maximum depth of the inner first intermediate cutting groove 32. The maximum depth of the outer first intermediate cutting groove 31 is 30% to 70% of the maximum depth of the inner first intermediate cutting groove 32, and in a preferred embodiment, it is 1.0 to 2.5 mm.

[0086] Among them, it can be applied to the outer first intermediate tool groove 31 and the inner first intermediate tool groove 32 respectively. Figure 6 The cross-sectional shape of the cutter groove is shown. Such an outer first intermediate cutter groove 31 and an inner first intermediate cutter groove 32 whiten the pitch tone of each cutter groove to improve noise performance, and also improve ride comfort and handling stability in a balanced way.

[0087] like Figure 3As shown, a first longitudinal groove 33 extending circumferentially along the tire is provided in the first intermediate land portion 12, for example. In this embodiment, the first longitudinal groove 33 extends continuously circumferentially along the tire. This first longitudinal groove 33 provides axial friction for the tire when driving on wet surfaces. Another embodiment of the first longitudinal groove 33 will be described later.

[0088] The first longitudinal groove 33 is provided, for example, in the central region where the first intermediate land portion 12 is divided into three equal parts in the tire axial direction. The distance in the tire axial direction from the first longitudinal groove 33 to the center position of the first intermediate land portion 12 is preferably less than 10% of the width W7 of the first intermediate land portion 12 in the tire axial direction, more preferably less than 5%. Such an arrangement of the first longitudinal groove 33 can suppress uneven wear of the first intermediate land portion 12.

[0089] Figure 7 Show Figure 3 A DD-line sectional view. For example... Figure 7 As shown, the first longitudinal groove 33 is formed, for example, from the opening end toward the bottom with a certain width.

[0090] Figure 8 Enlarged views of the first intermediate landmass 12, the crown landmass 13, and the second intermediate landmass 14 are shown. Figure 8 As shown, the land portion 13 of the tread includes a first longitudinal edge 13a on the side of the first tread end T1, a second longitudinal edge 13b on the side of the second tread end T2, and a tread surface between the first longitudinal edge 13a and the second longitudinal edge 13b. Similarly, the second intermediate land portion 14 includes a first longitudinal edge 14a on the side of the first tread end T1, a second longitudinal edge 14b on the side of the second tread end T2, and a tread surface between the first longitudinal edge 14a and the second longitudinal edge 14b.

[0091] like Figure 1 As shown, the axial width Wco of the outer contact surface 36 is, for example, 51% to 60% of the axial width W9 of the contact surface of the crown land portion 13, preferably 51% to 55%. This suppresses uneven wear of the crown land portion 13 and improves handling stability.

[0092] like Figure 8 As shown, only a sipes are provided on the land portion 13 of the tire crown. As a result, the rigidity of the land portion 13 of the tire crown is improved.

[0093] The land portion 13 of the tread is provided with a plurality of tread grooves 40 that are inclined relative to the tire axis in a second direction (lower right in the figures of this specification) opposite to the first direction. In this embodiment, the tread grooves 40 are inclined in the second direction and extend in a straight line. Such tread grooves 40 cooperate with the first intermediate groove 30 to provide friction in multiple directions, thereby improving wet performance.

[0094] The tire circumferential pitch length P3 of the crown sipe 40 is, for example, the tire circumferential pitch length P2 of the first intermediate sipe 30. Figure 3 The percentages (shown) are 80% to 120%, and in this embodiment, they are the same. This configuration of the tool grooves improves resistance to eccentric wear.

[0095] The angle of the tread groove 40 relative to the tire axial direction is preferably 20° or more, more preferably 25° or more, more preferably 45° or less, and more preferably 40° or less. The tread groove 40 provides friction evenly in both the tire circumferential and axial directions.

[0096] The crown groove 40 includes an outer crown groove 41 extending from the first longitudinal edge 13a and having an interrupted end 41a within the crown land portion 13; and an inner crown groove 42 extending from the second longitudinal edge 13b and having an interrupted end 42a within the crown land portion 13.

[0097] The angle difference between the outer crown sipe 41 and the inner crown sipe 42 is preferably 10° or less, more preferably 5° or less, and in this embodiment they are arranged in parallel. Such outer crown sipe 41 and inner crown sipe 42 suppress uneven wear of the crown land portion 13.

[0098] Both the outer crown sipe 41 and the inner crown sipe 42 do not traverse the center of the tire axial direction of the crown land portion 13, but are interrupted. The tire axial length L4 of the outer crown sipe 41 and the tire axial length L5 of the inner crown sipe 42 are, for example, 20% to 35% of the tire axial width W9 of the crown land portion 13. Such outer crown sipes 41 and inner crown sipes 42 improve both handling stability and ride comfort in a balanced way.

[0099] Preferably, the outer crown sipe 41 and the inner crown sipe 42 are misaligned in the tire circumferential direction. Therefore, in this embodiment, when viewed from above, the imaginary area formed by extending the outer crown sipe 41 parallel to the tire axial direction does not overlap with the inner crown sipe 42. Furthermore, the interrupted ends 41a of the outer crown sipe 41 and 42a of the inner crown sipe 42 are misaligned in the tire circumferential direction. Preferably, the tire circumferential distance L6 between the interrupted ends 41a of the outer crown sipe 41 and 42a of the inner crown sipe 42 is, for example, less than the tire circumferential distance Lb between the interrupted ends 31a of the outer first intermediate sipe 31 and 32a of the inner first intermediate sipe 32. Specifically, the distance L6 is preferably 70% or less of the distance Lb, more preferably 60% or less, more preferably 30% or more, and more preferably 40% or more. This configuration of the tool slots whitens the pitch tone of each slot, thus improving noise performance.

[0100] The outer crown sipe 41 and the inner crown sipe 42 each have a certain depth along their length. The depth of the inner crown sipe 42 is, for example, 70% to 100% of the depth of the circumferential groove 3. Furthermore, the maximum depth of the outer crown sipe 41 is less than the maximum depth of the inner crown sipe 42. The maximum depth of the outer crown sipe 41 is 30% to 70% of the maximum depth of the inner crown sipe 42, and in a preferred embodiment, it is 1.0 to 2.5 mm.

[0101] It can be applied to the outer tread groove 41 and the inner tread groove 42 respectively. Figure 6 The structure of the cross-sectional shape of the first intermediate tool groove 30 described herein. Therefore, the description here is omitted.

[0102] The second intermediate land portion 14 is provided with only a cutting groove. As a result, the rigidity of the second intermediate land portion 14 is improved.

[0103] A plurality of second intermediate grooves 45 are provided on the second intermediate land portion 14, which are inclined in the second direction relative to the tire axis. In this embodiment, the second intermediate grooves 45 are inclined in the second direction and extend in a straight line.

[0104] The tire circumferential pitch length P4 of the second intermediate sipe 45 is, for example, 80% to 120% of the tire circumferential pitch length P3 of the crown sipe 40; in this embodiment, they are the same. Such a sipe configuration improves resistance to eccentric wear.

[0105] The angle of the second intermediate sipe 45 relative to the tire axial direction is preferably 20° or more, more preferably 25° or more, preferably 45° or less, and more preferably 40° or less. The crown sipe 40 provides friction evenly in both the tire circumferential and axial directions.

[0106] The second intermediate groove 45 includes: an outer second intermediate groove 46 extending from the first longitudinal edge 14a and having an interrupted end 46a within the crown land portion 13; and an inner second intermediate groove 47 extending from the second longitudinal edge 14b and having an interrupted end 47a within the crown land portion 13.

[0107] The angle difference between the outer second intermediate cutting groove 46 and the inner second intermediate cutting groove 47 is preferably 10° or less, more preferably 5° or less, and in this embodiment they are arranged in parallel. Such outer second intermediate cutting groove 46 and inner second intermediate cutting groove 47 suppress uneven wear of the second intermediate land portion 14.

[0108] Both the outer second intermediate sipe 46 and the inner second intermediate sipe 47 do not traverse the center of the tire axial direction of the second intermediate land portion 14 but are interrupted. The tire axial length L7 of the outer second intermediate sipe 46 and the tire axial length L8 of the inner second intermediate sipe 47 are, for example, greater than the aforementioned length L4 of the outer crown sipe 41 and the aforementioned length L5 of the inner crown sipe 42. Furthermore, it is preferable that the tire axial length L7 of the outer second intermediate sipe 46 and the tire axial length L8 of the inner second intermediate sipe 47 are greater than the tire axial length of the first intermediate sipe 30. Specifically, the aforementioned length L7 of the outer second intermediate sipe 46 and the aforementioned length L8 of the inner second intermediate sipe 47 are 25% to 35% of the tire axial width W10 of the second intermediate land portion 14. Such outer second intermediate sipe 46 and inner second intermediate sipe 47 are beneficial for improving wet performance and ride comfort.

[0109] Preferably, the outer second intermediate sipe 46 and the inner second intermediate sipe 47 are misaligned in the tire circumferential direction. Therefore, in this embodiment, when viewed from above, the overlap area of ​​the imaginary region formed by the outer second intermediate sipe 46 extending parallel to the tire axial direction and the inner second intermediate sipe 47 is less than 10% of the opening area of ​​the inner second intermediate sipe 47. Furthermore, the interrupted ends 46a of the outer second intermediate sipe 46 and the inner second intermediate sipe 47a are misaligned in the tire circumferential direction. The tire circumferential distance L9 between the interrupted end 46a of the outer second intermediate sipe 46 and the interrupted end 47a of the inner second intermediate sipe 47 is, for example, smaller than the tire circumferential distance Lb between the interrupted end 31a of the outer first intermediate sipe 31 and the interrupted end 32a of the inner first intermediate sipe 32, and preferably smaller than the tire circumferential distance L6 between the interrupted end 41a of the outer crown sipe 41 and the interrupted end 42a of the inner crown sipe 42. Specifically, the distance L9 is preferably 80% or less of the distance L6, more preferably 70% or less, more preferably 40% or more, and more preferably 50% or more. This sipe configuration optimizes the rigidity balance of each land section, thereby improving both handling stability and ride comfort in a balanced manner.

[0110] The outer second intermediate sipe 46 and the inner second intermediate sipe 47 each have a certain depth along their length. The depth of the inner second intermediate sipe 47 is, for example, 70% to 100% of the depth of the circumferential groove 3. Furthermore, the maximum depth of the outer second intermediate sipe 46 is less than the maximum depth of the inner second intermediate sipe 47. The maximum depth of the outer second intermediate sipe 46 is 30% to 70% of the maximum depth of the inner second intermediate sipe 47, preferably 1.0 to 2.5 mm. Such outer crown sipes 41 and inner crown sipes 42 whiten the pitch noise of each sipe, improving noise performance, and also improving ride comfort and handling stability in a balanced way.

[0111] It can be applied to the outer second intermediate groove 46 and the inner second intermediate groove 47 respectively. Figure 6 The structure of the cross-sectional shape of the first intermediate tool groove 30 described herein. Therefore, the description here is omitted.

[0112] For example, a second longitudinal groove 48 extending circumferentially along the tire is provided in the second intermediate land portion 14. In this embodiment, the second longitudinal groove 48 extends continuously along the tire circumferential direction. In addition, the second longitudinal groove 48 has the same cross-sectional shape as the first longitudinal groove 33 described above. Such a second longitudinal groove 48 provides frictional force in the tire axial direction.

[0113] The second longitudinal groove 48 is provided, for example, in the central region when the second intermediate land portion 14 is divided into three equal parts in the tire axial direction. The distance in the tire axial direction from the second longitudinal groove 48 to the center position of the second intermediate land portion 14 is preferably 10% or less of the width W10 in the tire axial direction of the second intermediate land portion 14, more preferably 5% or less.

[0114] Figure 9 Show Figure 1 Enlarged view of the second tire's shoulder land portion 15. (See image below.) Figure 9 As shown, only a sipe is provided on the second shoulder land portion 15. As a result, the rigidity of the second intermediate land portion 14 is improved.

[0115] For example, a plurality of second shoulder grooves 50 extending along the tire axial direction are provided on the land portion 15 of the second shoulder. In this embodiment, the total number of second shoulder grooves 50 is greater than the number of first shoulder grooves 21. Figure 3 As shown, the same applies below. The total number of ( ). This configuration of cutter slots improves noise performance and wetland performance.

[0116] To maintain handling stability and improve noise and wet performance, the total number of the second shoulder sipes 50 is preferably equal to the number of the first shoulder sipes 21. Figure 3The total quantity (as shown) is more than 1.3 times, more preferably more than 1.5 times, even more preferably more than 1.8 times, preferably less than 2.8 times, more preferably less than 2.5 times, and even more preferably less than 2.2 times.

[0117] The tire circumferential pitch length P5 of the second shoulder sipe 50 is, for example, the tire circumferential pitch length P4 of the second center sipe 45. Figure 8 (shown) 30% to 70%.

[0118] The second shoulder sipe 50 is inclined in the first direction, for example. That is, the first shoulder sipe 21 and the second shoulder sipe 50 are inclined in the same direction relative to the tire axis. In this embodiment, the second shoulder sipe 50 is inclined in the first direction and extends in a straight line.

[0119] The angle of the second shoulder sipe 50 relative to the tire axial direction is, for example, 20° or less, preferably 15° or less, and more preferably 10° or less. Therefore, in this embodiment, the maximum angle of the first shoulder sipe 21 relative to the tire axial direction is greater than the maximum angle of the second shoulder sipe 50 relative to the tire axial direction. With this sipe configuration, noise performance is further improved.

[0120] Can be applied to the second tire shoulder groove 50 Figure 4 The cross-sectional shape of the first shoulder groove 21 is described in the text. Therefore, the description here is omitted.

[0121] The second shoulder groove 50 includes, for example, a transverse second shoulder groove 51 that completely traverses the second shoulder land portion 15 in the tire axial direction; and an interrupted second shoulder groove 52 that extends at least from the second tread end T2 in the tire axial direction and has an interrupted end within the second shoulder land portion 15.

[0122] The axial length of the interrupted second shoulder sipe 52 is greater than any one of the first intermediate sipe 30, the crown sipe 40, and the second intermediate sipe 45. The axial length L10 of the second shoulder sipe 50 is preferably 50% or more, more preferably 60% or more, more preferably 90% or less, and more preferably 80% or less, of the axial width W11 of the second shoulder land portion 15. This interruption of the second shoulder sipe 52 improves both ride comfort and handling stability in a balanced way.

[0123] Figure 10 Show Figure 9 A sectional view along the EE line. (e.g.) Figure 10 As shown, the second shoulder groove 51 includes a shallow bottom 53 with a partially raised bottom. In this embodiment, the shallow bottom 53 is, for example, provided in a connecting portion that communicates with the second shoulder circumferential groove 8. The shallow bottom 23 of the first shoulder groove 21 can be applied to the shallow bottom 53 of the second shoulder groove 50. Figure 5 The structure shown is omitted here. The shallow bottom 53 of the transverse second shoulder sipe 51 maintains the rigidity of the second shoulder land portion 15, thus improving handling stability.

[0124] like Figure 1 As shown, in this embodiment, each of the five land sections 4 is provided with only a cutter groove 16, and no drainage channel is provided. Therefore, the rigidity of each land section is maintained, and no suction noise from the drainage channel is generated; thus, improved noise performance can be expected.

[0125] As a further preferred embodiment, in this embodiment, the circumferential groove 3 includes a first groove wall 3a and a second groove wall 3b facing each other. The first groove wall 3a is provided with a plurality of first recesses 56 that are recessed outward in the groove width direction from the edge of the tread surface where the tread portion 2 of the circumferential groove 3 appears. Additionally, the second groove wall 3b is provided with a plurality of second recesses 57 that are recessed outward in the groove width direction from the edge of the tread surface where the tread portion 2 of the circumferential groove 3 appears. These first recesses 56 and second recesses 57 improve the drainage performance of the circumferential groove 3 and effectively suppress hydroplaning. Furthermore, the first recesses 56 and second recesses 57 are also expected to attenuate the sound pressure level of the noise generated by the circumferential groove 3, thus improving noise performance.

[0126] Preferably, the first recess 56 gradually decreases in depth from the deepest point of the recess along the outer edge of the groove towards both sides in the tire circumferential direction. Similarly, preferably, the second recess 57 gradually decreases in depth from the deepest point of the recess along the outer edge of the groove towards both sides in the tire circumferential direction. Such first recesses 56 and second recesses 57 prevent the formation of portions with locally reduced rigidity in the land portion, thereby suppressing uneven wear of the land portion.

[0127] To further improve the above effect, it is preferable that the first recess 56 and the second recess 57 are alternately arranged in the tire circumferential direction.

[0128] In this embodiment, a plurality of sipes communicating with the circumferential groove 3 are provided on the land portion. A first recess 56 and a second recess 57 are provided within a length range of 1.0 to 3.0 times the pitch length of one sipe. In other words, the tire circumferential length of the pair of first recesses 56 and second recesses 57 is 1.0 to 3.0 times the pitch length of one sipe. This maintains the rigidity of the land portion and improves noise performance.

[0129] Figure 11 Show Figure 1 FF line section view. Figure 12 Show Figure 1 A cross-sectional view along the GG line. (See example.) Figure 11 as well as Figure 12As shown, the first groove wall 3a and the second groove wall 3b have essentially the same shape. Furthermore, the first recess 56 and the second recess 57 have essentially the same shape. Therefore, the structure of the first groove wall 3a described below can be used for the second groove wall 3b. Additionally, the structure of the first recess 56 can be used for the second recess 57.

[0130] The first groove wall 3a includes an outer portion 18 that extends obliquely from the edge of the circumferential groove 3 toward the radially inward side of the tire in a direction that decreases the groove width. Additionally, the first groove wall 3a includes an inner portion 19 that extends obliquely from the outer portion 18 toward the radially inward side of the tire in a direction that increases the groove width and is connected to the bottom of the groove. This inner portion 19 forms the bottom surface of the first recess 56.

[0131] The radial height h1 of the first recess 56 is, for example, 30% to 70% of the total depth d6 of the circumferential groove 3, preferably 40% to 60%. Such a first recess 56 can suppress uneven wear on the land surface and improve wet performance and noise performance.

[0132] From the same perspective, the depth d7 of the first recess 56 is, for example, 1.0 to 3.0 mm, preferably 1.5 to 2.5 mm. Here, the aforementioned depth d7 corresponds to the distance in the groove width direction (parallel to the tread surface) from the first groove wall 3a where the first recess 56 is not located to the deepest part of the first recess 56. Furthermore, it is self-evident that the aforementioned height h1 and depth d7 of the first recess 56 can also be applied to the second recess 57.

[0133] Hereinafter, other embodiments of this disclosure will be described. In the figures illustrating other embodiments, the elements already described can be labeled with the same reference numerals as described above, and the above structure can be applied.

[0134] Figure 13 An enlarged view of the first intermediate land section 12 in another embodiment is shown. (See attached image.) Figure 13 As shown, the first longitudinal sipe 33 provided on the first intermediate land portion 12 extends in a serrated manner in the tire circumferential direction. The first longitudinal sipe 33 may also extend in a wavy, smooth curve, for example. The axial amplitude A1 (peak-to-peak value) of the first longitudinal sipe 33 is, for example, 1.0% to 8.0% of the axial width W7 of the first intermediate land portion 12. Furthermore, the first longitudinal sipe 33 extends in a serrated manner, forming a cycle of two pitches relative to the first intermediate sipe 30. Such a first longitudinal sipe 33 can also provide friction in the tire circumferential direction.

[0135] Figure 14 An enlarged view of the first intermediate land section 12 in yet another embodiment is shown. (See attached image.) Figure 14As shown, the first longitudinal sipe 33 provided on the first intermediate land portion 12 extends discontinuously in the tire circumferential direction. That is, the first longitudinal sipe 33 is composed of a plurality of longitudinal sipes 54 arranged in the tire circumferential direction. The tire circumferential length L11 of one longitudinal sipe 54 is, for example, 20% to 60% of the tire circumferential pitch length P2 of the first intermediate sipe 30. Such a first longitudinal sipe 33 can maintain the rigidity of the first intermediate land portion 12 and provide axial friction force for the tire.

[0136] Figure 13 as well as Figure 14 The structure of the first longitudinal cutter groove 33 shown can also be applied to the second longitudinal cutter groove 48 provided in the second intermediate land portion 14.

[0137] Figure 15 An enlarged view of the sidewall surface 60 of the first shoulder land portion 11 in yet another embodiment is shown. In this embodiment, Figure 15 In this text, the tread of the first tire shoulder land section 11 is omitted. For example... Figure 15 As shown, the first shoulder land portion 11 may also include a sidewall surface 60 that is axially outer of the first tread end T1. In this embodiment, the sidewall surface 60 is provided with a plurality of first shoulder lateral grooves 61 extending axially along the tire. Such first shoulder lateral grooves 61 can provide excellent wet performance and noise performance.

[0138] The minimum axial distance L12 of the tire from the first tread end T1 to the first shoulder lateral groove 61 is, for example, 10 mm or less. The aforementioned distance L12 is preferably 8 mm or less, more preferably 6 mm or less, more preferably 2 mm or more, and more preferably 4 mm or more. This results in a balanced improvement in both noise performance and wet performance.

[0139] The width W12 of the first shoulder transverse groove 61 is, for example, 3 to 15 mm. The groove width W12 is preferably 5 mm or more, more preferably 7 mm or more, preferably 13 mm or less, and even more preferably 11 mm or less. Furthermore, the maximum depth of the first shoulder transverse groove 61 is preferably 50% or more of the maximum depth of the circumferential groove 3, more preferably 60% or more, preferably 90% or less, and even more preferably 80% or less. With such a first shoulder transverse groove 61, wet performance and noise performance are improved in a balanced manner.

[0140] The first shoulder lateral groove 61 is inclined relative to the tire axis, for example. The angle of the first shoulder lateral groove 61 relative to the tire axis is, for example, 15° or less, preferably 10° or less.

[0141] The circumferential pitch length P6 of the first shoulder lateral groove 61 is, for example, 80% to 120% of the axial width of the tread of the first shoulder land portion 11.

[0142] Figure 16 An enlarged view of the sidewall surface 65 of the second shoulder land portion 15 of the above-described embodiment is shown. Wherein, in Figure 16 The tread of the second tire shoulder land section 15 is omitted. For example... Figure 16 As shown, the second shoulder land portion 15 in this embodiment may also include a sidewall surface 65 that is axially outer of the second tread end T2. In this embodiment, the sidewall surface 65 is provided with a plurality of second shoulder lateral grooves 66 extending axially along the tire. Such second shoulder lateral grooves 66 provide excellent wet performance and noise reduction.

[0143] To reliably improve wet performance, the minimum axial distance L13 of the tire from the second tread end T2 to the second shoulder lateral groove 66 is, for example, 10 mm or less. The aforementioned distance L13 is preferably 8 mm or less, more preferably 6 mm or less, more preferably 2 mm or more, and even more preferably 4 mm or more. This results in a balanced improvement in both noise performance and wet performance.

[0144] The width W13 of the second shoulder lateral groove 66 is, for example, 3 to 15 mm. Furthermore, the maximum depth of the second shoulder lateral groove 66 is preferably 50% or more, more preferably 60% or more, more preferably 90% or less, and even more preferably 80% or less, of the maximum depth of the circumferential groove 3. Such a second shoulder lateral groove 66 improves both wetland performance and noise performance in a balanced way.

[0145] The tire circumferential pitch length P7 of the second shoulder lateral groove 66, for example, the tire circumferential pitch length P6 of the first shoulder lateral groove 61. Figure 15 (as shown) 80% to 120%, preferably the same.

[0146] Figure 17 An enlarged view of the tread portion 2 of yet another embodiment is shown. Figure 18 A cross-sectional view of a representative cutter groove 16 of this embodiment is shown. (As shown) Figure 18 As shown, the cutting groove 16 in this embodiment may, for example, have at least one of the two cutting groove edges formed by a chamfer 67. In the cutting groove 9 of this embodiment, both cutting groove edges are formed by chamfers 67. Hereinafter, such a cutting groove 16 will sometimes be referred to as a chamfered cutting groove. The chamfer 67 is formed by an inclined surface 68 connected to the ground surface and the cutting groove wall 16w. The angle of the inclined surface 68 relative to the depth direction of the cutting groove 16 is, for example, 30 to 60°.

[0147] like Figure 17As shown, in this embodiment, the first shoulder land portion 11 is provided with a plurality of first shoulder grooves 70 extending from the first shoulder circumferential groove 5 to a position beyond the first tread end T1. Preferably, the first shoulder grooves 70 include, for example, an inclined portion 71 extending obliquely from the first shoulder circumferential groove 5 relative to the tire axis; an axial portion 72 having an angle with respect to the tire axis smaller than that of the inclined portion 71 and less than 10°; and a curved portion 73 extending obliquely between the inclined portion 71 and the axial portion 72.

[0148] The first shoulder sipe 70 is constructed as the aforementioned chamfered sipe, with both sides of the sipe edges forming a chamfered portion. Furthermore, when viewed from above, the width of the chamfered portion of the first shoulder sipe 70 increases towards the outer axial direction of the tire. Specifically, the chamfered portions of the inclined portion 71 and the axial portion 72 extend with a certain width, and the width of the chamfered portion of the curved portion 73 increases towards the outer axial direction of the tire. Therefore, when viewed from above, the width of the chamfered portion of the axial portion 72 is greater than the width of the chamfered portion of the inclined portion 71. Specifically, the width of the chamfered portion of the axial portion 72 is 1.5 to 2.5 times the width of the chamfered portion of the inclined portion 71. The first shoulder sipe 70 with such a chamfered portion can effectively suppress uneven wear near the first tread end T1. It is self-evident that the aforementioned width of the chamfered portion refers to the width in the direction perpendicular to the length direction of the sipe when viewed from above.

[0149] In this embodiment, a plurality of shoulder interruption grooves 75 are provided on the first shoulder land portion 11. The shoulder interruption grooves 75 extend from the periphery of the first shoulder toward the groove 5 and are interrupted without reaching the first tread end T1. The shoulder interruption grooves 75 are preferably configured, for example, as chamfered grooves. The chamfered portion of the shoulder interruption grooves 75 decreases in width as it moves from the periphery of the first shoulder toward the groove 5 side toward the axially outer side of the tire.

[0150] In this embodiment, the second shoulder land portion 15 is provided with a plurality of second shoulder grooves 76 that are the same as the first shoulder groove 70 described above, and the description here is omitted.

[0151] In this embodiment, a plurality of first intermediate grooves 77 are provided in the first intermediate land portion 12. The first intermediate grooves 77 are inclined relative to the tire axial direction and completely traverse the first intermediate land portion 12 in the tire axial direction.

[0152] The first intermediate sipe 77 is configured, for example, as a chamfered sipe. Specifically, the entire edge of the sipes on both sides of the first intermediate sipe 77 is formed by a chamfer. Furthermore, when viewed from above, the width of the chamfer of the first intermediate sipe 77 continuously increases towards the tire equator C side. Thus, the width of the chamfer becomes the largest at the end of the first intermediate sipe 77 on the tire equator C side. In a more preferred embodiment, the maximum width of the chamfer of the first intermediate sipe 77 is greater than the maximum width of the chamfer of the inclined portion 71 of the first shoulder sipe 70. This suppresses uneven wear on the first intermediate land portion 12 and improves handling stability and noise performance.

[0153] A plurality of second intermediate cutting grooves 78 are provided on the second intermediate land portion 14. The structure of the first intermediate cutting groove 77 described above can be applied to the second intermediate cutting grooves 78, and the description here is omitted.

[0154] The land portion 13 of the tire crown is provided with a plurality of first crown grooves 81 and a plurality of second crown grooves 82. The first crown grooves 81 extend from the periphery of the first crown toward the groove 6, for example, and are interrupted within the land portion 13 of the tire crown. The second crown grooves 82 extend from the periphery of the second crown toward the groove 7, for example, and are interrupted within the land portion 13 of the tire crown.

[0155] The first crown sipe 81 and the second crown sipe 82 are each configured as chamfered sipes. In a preferred embodiment, the width of the chamfered portion of the first crown sipe 81 and the second crown sipe 82 decreases towards the tire equator C. Such first crown sipes 81 and the second crown sipe 82 can suppress uneven wear of the crown land portion 13.

[0156] 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.

[0157] Example

[0158] Based on the specifications in Tables 1-3, prototypes were manufactured with... Figure 1 The basic tread pattern is for a 235 / 55R19 tire. Additionally, a prototype tire with [specific tread pattern] was manufactured as a benchmark tire for comparing noise performance. Figure 19 The tire with the pattern shown.

[0159] Each land section of the reference tire is equipped with a... Figure 1The sipe shown is a structure formed by removing the wide portion. Furthermore, for the reference tire, the width Wa of the first shoulder land portion a is the same as the width We of the second shoulder land portion e. Additionally, the width Wb of the first intermediate land portion b, the width Wc of the crown land portion c, and the width Wd of the second intermediate land portion d are the same. Furthermore, the widths Wa and We are greater than the widths Wc, Wd, and We. Therefore, for the reference tire, under a 50% load condition, when the widths of the contact surfaces along the tire axial direction of the first shoulder land portion a, the first intermediate land portion b, the crown land portion c, the second intermediate land portion d, and the second shoulder land portion e are set to W1s, W1m, Wc, W2m, and W2s respectively, the following equation (5) is satisfied. Furthermore, the width Wco of the outer contact surface and the width Wci of the inner contact surface of the crown land portion d are the same.

[0160] W1s=W2s>W1m=Wc=W2m…(5)

[0161] In addition, as a comparative example, a prototype with... Figure 20 The tire with the pattern shown. For the comparative example tire, the width distribution of the land portion is the same as the reference tire, and... Figure 1 Similarly, each cutting groove has a wide section. The comparative example tire, except for the above-mentioned aspects, is otherwise similar. Figure 1 The conditions shown are essentially the same. The handling stability and noise performance of each test tire on a dry road surface were tested. The common specifications and test methods for all test tires are as follows.

[0162] Wheel rim: 19×7.0J

[0163] Tire internal pressure: 230 kPa

[0164] Test vehicle: 2000cc engine, four-wheel drive

[0165] Tire mounting location: All wheels

[0166] Handling stability on dry surfaces

[0167] The handling stability of the test vehicles on dry roads was evaluated by the driver's senses when driving on ordinary roads. The results are expressed as a score of 100 for the handling stability of the comparative examples; the higher the score, the better the handling stability on dry roads.

[0168] <Noise Performance>

[0169] The test vehicle was driven at speeds of 40–100 km / h on a dry road surface, and the maximum sound pressure level inside the vehicle was measured. The results were expressed as the difference in sound pressure level compared to that of a reference tire, i.e., the reduction in sound pressure, using an index where the reduction in sound pressure level for the comparative example is 100. A larger index indicates a lower maximum sound pressure level and superior noise performance.

[0170] The test results are shown in Tables 1-3.

[0171] Table 1

[0172]

[0173] Table 2

[0174]

[0175] Table 3

[0176]

[0177] The test results confirm that the tires of the embodiment exhibit improved handling stability on dry roads. Furthermore, the tire noise performance of the embodiment is also confirmed to be improved.

[0178] [Postscript]

[0179] This disclosure includes the following methods.

[0180] [This disclosure 1]

[0181] A tire has a tread portion with a specified orientation for mounting on a vehicle, the tread portion including: a first tread end that becomes the outer side of the vehicle when mounted on the vehicle; a second tread end that becomes the inner side of the vehicle when mounted on the vehicle; a plurality of circumferential grooves extending continuously in the tire circumferential direction between the first tread end and the second tread end; and a plurality of land portions divided by the circumferential grooves.

[0182] The aforementioned multiple land portions include: a crown land portion disposed on the tire equator, a first intermediate land portion adjacent to the first tread end side of the crown land portion, and a second intermediate land portion adjacent to the second tread end side of the crown land portion. When the rim is assembled with a regular internal pressure and a regular load is applied with a 50% load applied to the ground plane at a 0° camber angle, and the widths of the tire axial contact surfaces of the first intermediate land portion, the crown land portion, and the second intermediate land portion are respectively set to W1m, Wc, and W2m, the following equation (1) is satisfied. The crown land portion includes an outer contact surface that is closer to the first tread end side than the tire equator and an inner contact surface that is closer to the second tread end side than the tire equator. When the widths of the outer contact surface and the inner contact surface in the tire axial direction are respectively set to Wco and Wci, the following equation (2) is satisfied.

[0183] W1m>Wc>W2m…(1)

[0184] Wco>Wci…(2)

[0185] [This disclosure 2]

[0186] In the tire described in this disclosure 1, the axial width of the outer contact surface is 51% to 55% of the axial width of the contact surface of the crown land portion.

[0187] [This disclosure 3]

[0188] In the tire described in disclosure 1 or 2, a first longitudinal groove extending in the circumferential direction of the tire is provided in the first intermediate land portion.

[0189] [This disclosure 4]

[0190] In the tire described in this disclosure 3, the first longitudinal groove extends continuously along the tire circumferential direction.

[0191] [This disclosure 5]

[0192] In the tire described in this disclosure 4, the first longitudinal groove extends in a serrated shape.

[0193] [This disclosure 6]

[0194] In the tire described in this disclosure 3, the first longitudinal groove extends discontinuously along the tire circumferential direction.

[0195] [This disclosure 7]

[0196] In any one of the tires disclosed in this disclosure 1 to 6, the first intermediate land portion includes: a first longitudinal edge on the first tread end side, a second longitudinal edge on the second tread end side, and a tread surface between the first longitudinal edge and the second longitudinal edge. The first intermediate land portion is provided with: an outer first intermediate sipe that communicates with the first longitudinal edge and has an interrupted end in the first intermediate land portion; and an inner first intermediate sipe that communicates with the second longitudinal edge and has an interrupted end in the first intermediate land portion.

[0197] [This disclosure is 8]

[0198] In the tire described in this disclosure 7, the axial length of the outer first intermediate sipe is 20% to 45% of the axial width of the first intermediate land portion.

[0199] [This disclosure is number 9]

[0200] In the tire described in disclosure 7 or 8, the axial length of the inner first intermediate sipe is 20% to 45% of the axial width of the first intermediate land portion.

[0201] [This disclosure is number 10]

[0202] In any one of the tires disclosed in this disclosure 1 to 9, the circumferential groove includes a first groove wall and a second groove wall facing each other. The first groove wall is provided with a plurality of first recesses that are recessed outward in the groove width direction from the groove edge where the tread surface of the tread surface of the circumferential groove appears. The second groove wall is provided with a plurality of second recesses that are recessed outward in the groove width direction from the groove edge where the tread surface of the tread surface of the circumferential groove appears. The amount of recess of the first and second recesses gradually decreases from the groove edge as they move from the deepest recessed part in the groove width direction toward both sides of the tire circumferential direction. In the land portion adjacent to the circumferential groove, a plurality of sipes communicating with the circumferential groove are provided along the tire circumferential direction. One of the first recesses and one of the second recesses are provided within a length range of 1.0 to 3.0 times the pitch length of one sipe.

[0203] [This disclosure is number 11]

[0204] In the tire described in this disclosure 1, the plurality of land portions include a first shoulder land portion including the first tread end, the first shoulder land portion including a sidewall surface that is axially outer of the first tread end, and a plurality of first shoulder lateral grooves extending axially along the tire are provided on the sidewall surface.

[0205] [This disclosure is number 12]

[0206] In the tire described in this disclosure 11, the minimum distance in the tire axial direction from the first tread end to the first shoulder lateral groove is 10 mm or less.

[0207] [This disclosure is number 13]

[0208] In the tires described in disclosure 11 or 12, the width of the first shoulder lateral groove is 3 to 15 mm.

[0209] [This disclosure 14]

[0210] In any one of the tires disclosed in 11 to 13, the maximum depth of the first shoulder transverse groove is 50% to 90% of the maximum depth of the circumferential groove.

[0211] [This disclosure is 15]

[0212] In any one of the tires disclosed in 11 to 14, the plurality of land portions include a second shoulder land portion including the second tread end, the second shoulder land portion including a sidewall surface that is axially outer of the second tread end, and a plurality of second shoulder lateral grooves extending axially along the tire are provided on the sidewall surface of the second shoulder land portion.

[0213] [This disclosure is number 16]

[0214] In the tire described in this disclosure 1, a plurality of sipes are provided in the plurality of land portions, the sipes including at least one of the sipe edges on both sides being formed by a chamfered portion, the chamfered portion including an inclined surface connected to the tread surface of the land portion and the sipe wall of the sipe.

[0215] [This disclosure is number 17]

[0216] In the tire described in this disclosure 16, the plurality of land portions include a first shoulder land portion including the first tread end, the plurality of circumferential grooves include a first shoulder circumferential groove adjacent to the first shoulder land portion, and a plurality of first shoulder sipes are provided on the first shoulder land portion extending from the first shoulder circumferential groove to a position beyond the first tread end. The first shoulder sipes are configured as chamfered sipes. The first shoulder sipes include: an inclined portion extending obliquely from the first shoulder circumferential groove relative to the tire axis; and an axial portion whose angle relative to the tire axis is smaller than the inclined portion and is less than 10°. When the tread is viewed from above, the width of the chamfered portion of the axial portion is greater than the width of the chamfered portion of the inclined portion.

[0217] [This disclosure is number 18]

[0218] In the tire described in this disclosure 17, the first shoulder groove includes a curved portion extending curvedly between the inclined portion and the axial portion, and when viewed from above, the width of the chamfered portion of the curved portion increases toward the axially outer side of the tire.

[0219] [This disclosure 19]

[0220] In any one of the tires disclosed in this disclosure 16 to 18, a plurality of first intermediate sipes are provided in the first intermediate land portion, which completely traverse the first intermediate land portion in the tire axial direction. The first intermediate sipes are configured as chamfered sipes. When the tire tread is viewed from above, the width of the chamfered portion of the first intermediate sipes continuously increases toward the equatorial side of the tire.

[0221] [This disclosure 20]

[0222] In any one of the tires disclosed in this disclosure 16 to 19, a plurality of second intermediate sipes are provided in the second intermediate land portion, which completely traverse the second intermediate land portion in the tire axial direction. The second intermediate sipes are configured as chamfered sipes. When the tire tread is viewed from above, the width of the chamfered portion of the second intermediate sipes continuously increases toward the equatorial side of the tire.

Claims

1. A tire having a tread portion facing a specified orientation for mounting on a vehicle, characterized in that, The tread portion includes: a first tread end that becomes the outer side of the vehicle when mounted on the vehicle; a second tread end that becomes the inner side of the vehicle when mounted on the vehicle; a plurality of circumferential grooves extending continuously along the tire circumference between the first tread end and the second tread end; and a plurality of land portions divided by the circumferential grooves. The plurality of land portions include: a crown land portion disposed on the tire equator, a first intermediate land portion adjacent to the first tread end side of the crown land portion, a second intermediate land portion adjacent to the second tread end side of the crown land portion, a first shoulder land portion including the first tread end, and a second shoulder land portion including the second tread end. When the rim is assembled with normal internal pressure and a normal load is applied with a 50% load applied to the ground plane at a 0° camber angle, and the widths of the contact surfaces of the first intermediate land section, the crown land section, the second intermediate land section, the first shoulder land section, and the second shoulder land section are respectively set as W1m, Wc, W2m, W1s, and W2s, the following equation (1) is satisfied. The land portion of the tire crown includes an outer contact surface at the first tread end, which is closer to the tire equator, and an inner contact surface at the second tread end, which is closer to the tire equator. When the widths of the outer contact surface and the inner contact surface of the tire axial direction are set as Wco and Wci respectively, the following equation (2) is satisfied. W1s>W1m>Wc>W2m≥W2s…(1), Wco>Wci…(2), The first intermediate land portion includes: a first longitudinal edge on the first tread end side, a second longitudinal edge on the second tread end side, and a tread surface between the first longitudinal edge and the second longitudinal edge. The first intermediate land portion is provided with: an outer first intermediate cutting groove that communicates with the first longitudinal edge and has an interrupted end within the first intermediate land portion; and an inner first intermediate cutting groove that communicates with the second longitudinal edge and has an interrupted end within the first intermediate land portion. The outer first intermediate sipe and the inner first intermediate sipe each include: a main body extending radially along the tire, and a wide portion that opens at the tread surface of the land portion and has a width larger than the main body. The first shoulder land portion is provided with a plurality of first shoulder sipes extending along the tire axial direction. The first shoulder groove includes: a main body extending radially along the tire, and a wide portion that opens at the tread of the land portion and has a width larger than the main body. The opening width W4 of the first shoulder sipe at the tread surface is greater than the opening width W5 of the outer first intermediate sipe or the inner first intermediate sipe at the tread surface. The depth d1 of the wide portion of the first shoulder groove is less than the depth d2 of the wide portion of the outer first intermediate groove or the inner first intermediate groove.

2. The tire according to claim 1, characterized in that, The axial width of the outer contact surface of the tire is 51% to 55% of the axial width of the contact surface of the land portion of the tread.

3. The tire according to claim 1 or 2, characterized in that, A first longitudinal groove extending along the tire circumference is provided in the first intermediate land portion.

4. The tire according to claim 3, characterized in that, The first longitudinal groove extends continuously along the tire circumference.

5. The tire according to claim 4, characterized in that, The first longitudinal groove extends in a serrated shape.

6. The tire according to claim 3, characterized in that, The first longitudinal groove extends intermittently along the tire circumference.

7. The tire according to any one of claims 1, 2, 4 to 6, characterized in that, The axial length of the outer first intermediate sipe is 20% to 45% of the axial width of the first intermediate land portion of the tire.

8. The tire according to any one of claims 1, 2, 4 to 6, characterized in that, The axial length of the inner first intermediate sipe is 20% to 45% of the axial width of the first intermediate land portion of the tire.

9. The tire according to any one of claims 1, 2, 4 to 6, characterized in that, The circumferential trench includes a first trench wall and a second trench wall facing each other. The first groove wall is provided with a plurality of first recesses that are recessed outward in the groove width direction from the groove edge of the tread surface where the circumferential groove appears. The second groove wall is provided with a plurality of second recesses that are recessed outward in the groove width direction from the groove edge of the tread surface where the circumferential groove appears. The first and second recesses gradually decrease in depth from the groove edge as they extend from the deepest, most recessed portion towards both sides of the tire circumferential direction. In the land portion adjacent to the circumferential groove, a plurality of sipes communicating with the circumferential groove are provided along the tire circumference. Within a length range of 1.0 to 3.0 times the pitch length of the cutter groove, a first recess and a second recess are provided.

10. The tire according to claim 1, characterized in that, The first shoulder land portion includes a sidewall surface that is axially outer of the tire than the first tread end. The tire sidewall surface is provided with a plurality of first shoulder transverse grooves extending along the tire axial direction.

11. The tire according to claim 10, characterized in that, The minimum distance in the tire axial direction from the end of the first tread to the first shoulder groove is less than 10 mm.

12. The tire according to claim 10 or 11, characterized in that, The width of the first shoulder transverse groove is 3–15 mm.

13. The tire according to claim 10 or 11, characterized in that, The maximum depth of the first shoulder transverse groove is 50% to 90% of the maximum depth of the circumferential groove.

14. The tire according to claim 10 or 11, characterized in that, The second shoulder land portion includes a sidewall surface that is axially outer of the tire than the second tread end. The sidewall surface of the second shoulder land portion is provided with a plurality of second shoulder transverse grooves extending along the tire axial direction.

15. A tire having a tread portion facing a specified orientation for mounting on a vehicle, characterized in that, The tread portion includes: a first tread end that becomes the outer side of the vehicle when mounted on the vehicle; a second tread end that becomes the inner side of the vehicle when mounted on the vehicle; a plurality of circumferential grooves extending continuously along the tire circumference between the first tread end and the second tread end; and a plurality of land portions divided by the circumferential grooves. The plurality of land portions include: a crown land portion disposed on the tire equator, a first intermediate land portion adjacent to the first tread end side of the crown land portion, a second intermediate land portion adjacent to the second tread end side of the crown land portion, a first shoulder land portion including the first tread end, and a second shoulder land portion including the second tread end. When the rim is assembled with normal internal pressure and a normal load is applied with a 50% load applied to the ground plane at a 0° camber angle, and the widths of the contact surfaces of the first intermediate land section, the crown land section, the second intermediate land section, the first shoulder land section, and the second shoulder land section are respectively set as W1m, Wc, W2m, W1s, and W2s, the following equation (1) is satisfied. The land portion of the tire crown includes an outer contact surface at the first tread end, which is closer to the tire equator, and an inner contact surface at the second tread end, which is closer to the tire equator. When the widths of the outer contact surface and the inner contact surface of the tire axial direction are set as Wco and Wci respectively, the following equation (2) is satisfied. W1s>W1m>Wc>W2m≥W2s…(1), Wco>Wci…(2), Multiple cutter grooves are provided on the multiple land sections. The cutting groove includes a chamfered cutting groove formed by a chamfered portion on at least one of the cutting groove edges on both sides. The chamfered portion includes an inclined surface that connects to the tread surface of the land portion and the groove wall of the cutting groove. The plurality of circumferential grooves include a first shoulder circumferential groove adjacent to the land portion of the first shoulder. The first shoulder land portion is provided with a plurality of first shoulder sipes extending from the circumferential groove of the first shoulder to a position beyond the end of the first tread. The first shoulder sipe is formed as the chamfered sipe. The first shoulder groove includes: an inclined portion extending obliquely from the first shoulder circumferential groove relative to the tire axial direction; and an axial portion whose angle relative to the tire axial direction is smaller than the inclined portion and less than 10°. When viewed from above, the width of the chamfered portion of the axial section is greater than the width of the chamfered portion of the inclined section. The first shoulder groove includes a curved portion that extends curvedly between the inclined portion and the axial portion. When viewed from above, the width of the chamfered portion of the curved section increases as it moves outward toward the axial direction of the tire.

16. The tire according to claim 15, characterized in that, The first intermediate land portion is provided with a plurality of first intermediate sipes that completely traverse the first intermediate land portion in the tire axial direction. The first intermediate cutting groove is formed as the chamfering cutting groove. When viewed from above, the width of the chamfered portion of the first intermediate sipe increases continuously toward the equator side of the tire.

17. The tire according to claim 15 or 16, characterized in that, The second intermediate land portion is provided with a plurality of second intermediate sipes that completely traverse the second intermediate land portion in the tire axial direction. The second intermediate cutting groove is formed as the chamfering cutting groove. When viewed from above, the width of the chamfered portion of the second intermediate sipe increases continuously toward the equator side of the tire.

Images