Tire

Abstract

To provide a tire which improves ride comfort and noise performance.SOLUTION: A tire has a tread part 2 having a specified mounting direction to a vehicle. On five land parts 4 of the tread part 2, sipes 16 are provided, respectively. The five land parts 4 include a first shoulder land part 11, a second shoulder land part 15, a first middle land part 12, a second middle land part 14, and a crown land part 13. In a 50% load state where the tire is rim-assembled at a normal inner pressure in a normal rim, a normal load is applied thereto, and is brought into ground contact with a plane at a camber angle of 0°, when widths of contact surfaces in a tire axial direction of the first shoulder land part, the first middle land part, the crown land part, the second middle land part, and the second shoulder land part are represented by W1s, W1m, Wc, W2m and W2s, respectively, the following expression (1) is satisfied. Expression (1): W1s>W1m>Wc>W2 m≥W2s.SELECTED DRAWING: Figure 1

Description

Technical Field

[0001] The present disclosure relates to a tire.

Background Art

[0002] Patent Document 1 below proposes a pneumatic tire in which the tread portion is configured to include five land portions. The land portions include a crown land portion, a pair of middle land portions, and a pair of shoulder land portions.

[0003] An inner lug groove, an outer lug groove, and an intermediate slot extending in the tire axial direction therebetween are formed in the shoulder land portion. The inner lug groove extends outward in the tire axial direction from the shoulder circumferential groove and terminates before the grounding end. The outer lug groove extends inward in the tire axial direction from the grounding end and terminates before the shoulder circumferential groove without intersecting the inner lug groove. The intermediate slot terminates without reaching the shoulder circumferential groove at its inner end in the tire axial direction and terminates without reaching the grounding end at its outer end in the tire axial direction.

[0004] Thereby, the pneumatic tire is continuous in the tire circumferential direction without the shoulder land portion being interrupted. The pneumatic tire expects to maintain drainage performance, suppress heel and toe wear of the shoulder land portion, and improve noise performance due to the above-described features.

Prior Art Documents

Patent Documents

[0005]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0006] In recent years, there has been a demand for further improvement in ride comfort and noise performance of tires. Developers have found that in a tire whose tread portion includes five land portions, by reexamining the relationship of the widths of the respective land portions, the above-described performance can be improved, and thus the present disclosure has been completed.

[0007] The present disclosure has been devised in view of the above problems, and the main object thereof is to provide a tire with improved ride comfort and noise performance.

Means for Solving the Problems

[0008] The present disclosure is a tire having a tread portion with a specified mounting direction on a vehicle, wherein the tread portion includes a first tread end that becomes the outside of the vehicle when mounted on the vehicle, a second tread end that becomes the inside of the vehicle when mounted on the vehicle, four circumferential grooves continuously extending in the tire circumferential direction between the first tread end and the second tread end, and five land portions divided by the circumferential grooves. Each of the five land portions is provided with sipes. The five land portions include a first shoulder land portion including the first tread end, a second shoulder land portion including the second tread end, a first middle land portion adjacent to the first shoulder land portion, a second middle land portion adjacent to the second shoulder land portion, and a crown land portion between the first middle land portion and the second middle land portion. In a 50% load-bearing state where the tire is mounted on a standard rim at a standard internal pressure and loaded with 50% of the standard load and grounded on a flat surface at a camber angle of 0°, when the widths of the ground contact surfaces of the first shoulder land portion, the first middle land portion, the crown land portion, the second middle land portion, and the second shoulder land portion in the tire axial direction are W1s, W1m, Wc, W2m, and W2s, respectively, the tire satisfies the following formula (1). W1s>W1m>Wc>W2m≧W2s …(1)

Effects of the Invention

[0009] By adopting the above configuration, the tire of the present disclosure can improve ride comfort and noise performance.

Brief Description of the Drawings

[0010]

Figure 1

Figure 2

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Figure 4

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Figure 8

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Figure 11

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Figure 16

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Figure 21

Mode for Carrying Out the Invention

[0011] Hereinafter, an embodiment of the present disclosure will be described with reference to the drawings. FIG. 1 is a developed view of a tread portion 2 of a tire 1 showing an embodiment of the present disclosure. The tire 1 of the present embodiment is suitably used, for example, as a pneumatic tire for a passenger car. However, the present disclosure is not limited to such a mode, and may be applied to a pneumatic tire for heavy loads or a non-pneumatic tire in which the inside of the tire is not filled with pressurized air.

[0012] As shown in FIG. 1, the tire 1 of the present disclosure has a tread portion 2 in which the mounting direction on the vehicle is specified. The tread portion 2 has a first tread end T1 intended to be located on the outside of the vehicle when the tire 1 is mounted on the vehicle, and a second tread end T2 intended to be located on the inside of the vehicle when the tire 1 is mounted on the vehicle. The mounting direction on the vehicle is indicated, for example, by letters or symbols on a sidewall portion (not shown).

[0013] The first tread end T1 and the second tread end T2 respectively correspond to the outermost ground contact positions in the tire axial direction when 50% of the normal load is applied to the tire 1 in the normal state and the tire is grounded on a plane at a camber angle of 0°.

[0014] The "normal state" means that in the case of a pneumatic tire for which various standards are defined, the tire is rim-mounted on a normal rim and filled with a normal internal pressure, and moreover, it is in a non-loaded state. In the case of a tire for which various standards are not defined or a non-pneumatic tire, the normal state means a standard use state according to the purpose of use of the tire, and the tire is not mounted on a vehicle and is in a non-loaded state. In this specification, unless otherwise specified, the dimensions and the like of each part of the tire are values measured in the normal state. Note that each configuration described in this specification allows for normal errors included in rubber molded products.

[0015] The "regular rim" is the rim defined for each tire in the standard system including the standards on which the tire is based. For example, in JATMA, it is the "standard rim", in TRA, it is the "Design Rim", and in ETRTO, it is the "Measuring Rim".

[0016] The "regular internal pressure" is the air pressure defined for each tire in the standard system including the standards on which the tire is based. In JATMA, it is the "maximum air pressure", in TRA, it is the maximum value described in the table "TIRE LOAD LIMITS AT VARIOUS COLD INFLATION PRESSURES", and in ETRTO, it is the "INFLATION PRESSURE".

[0017] The "regular load" is, in the case of a pneumatic tire for which various standards are defined, the load defined for each tire in the standard system including the standards on which the tire is based. In JATMA, it is the "maximum load capacity", in TRA, it is the maximum value described in the table "TIRE LOAD LIMITS AT VARIOUS COLD INFLATION PRESSURES", and in ETRTO, it is the "LOAD CAPACITY". Further, in the case of a tire for which no various standards are defined or a non-pneumatic tire, the "regular load" refers to the load acting on one tire in the standard mounting state of the tire. The "standard mounting state" refers to a state in which the tire is mounted on a standard vehicle according to the purpose of use of the tire and the vehicle is stationary on a flat road surface in a state where the vehicle can run.

[0018] The tread portion 2 has a plurality of circumferential grooves 3 continuously extending in the circumferential direction of the tire between a first tread end T1 and a second tread end T2, and a plurality of land portions 4 divided by the circumferential grooves. The tire 1 of the present embodiment is configured as a so-called 5-rib tire in which the tread portion 2 includes five land portions 4 divided by four circumferential grooves 3.

[0019] 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 provided between the first tread end T1 and the tire equator C. The second shoulder circumferential groove 8 is provided between the second tread end T2 and the tire equator C. The first crown circumferential groove 6 is provided between the first shoulder circumferential groove 5 and the tire equator C. The second crown circumferential groove 7 is provided between the second shoulder circumferential groove 8 and the tire equator C.

[0020] The distance L1 in the tire axial direction from the tire equator C to the groove center line of the first shoulder circumferential groove 5 or the second shoulder circumferential groove 8 is preferably, for example, 25% to 35% of the tread width TW. The distance L2 in the tire axial direction from the tire equator C to the groove center line of the first crown circumferential groove 6 or the second crown circumferential groove 7 is preferably, for example, 5% to 15% of the tread width TW. Note that the tread width TW is the distance in the tire axial direction from the first tread end T1 to the second tread end T2 in the normal state.

[0021] Each circumferential groove 3 of the present embodiment extends linearly in parallel with the tire circumferential direction, for example. Each circumferential groove 3 may extend in a wavy shape, for example.

[0022] The groove width W1 of each circumferential groove 3 is, for example, 2.0% to 10.0% of the tread width TW, and more preferably 2.0% to 8.0%. In the present embodiment, the first shoulder circumferential groove 5 has the smallest groove width among the four circumferential grooves 3. Also, the first crown circumferential groove 6 has the second smallest groove width among the four circumferential grooves 3. Thereby, the rigidity is increased on the first tread end T1 side of the tread portion 2, and as a result, the braking performance, noise performance, and handling stability are improved in a well-balanced manner. However, the present disclosure is not limited to such a mode. The depth of each circumferential groove 3 is preferably, for example, 5 to 10 mm in the case of a pneumatic tire for a passenger car.

[0023] More specifically, it is desirable that the groove width of the first shoulder circumferential groove 5 be 2.9% to 4.0% of the tread width TW. Further, the groove width of the first crown circumferential groove 6 is, for example, 5.6% to 8.7% of the tread width TW, and desirably 5.6% to 7.4%. The groove widths of the second shoulder circumferential groove 8 and the second crown circumferential groove 7 are, for example, 6.4% to 9.6% respectively, and desirably 7.7% to 9.6%.

[0024] The land portion 4 of the present disclosure includes a first shoulder land portion 11, a first middle land portion 12, a crown land portion 13, a second middle land portion 14, and a second shoulder land portion 15. The first shoulder land portion 11 includes a first tread end T1. The second shoulder land portion 15 includes a second tread end T2.

[0025] The first middle land portion 12 is divided into a first shoulder circumferential groove 5 and a first crown circumferential groove 6, and is adjacent to the second tread end T2 side of the first shoulder land portion 11. The second middle land portion 14 is divided into a second shoulder circumferential groove 8 and a second crown circumferential groove 7, and is adjacent to the first tread end T1 side of the second shoulder land portion 15.

[0026] The crown land portion 13 is divided between the first crown circumferential groove 6 and the second crown circumferential groove 7. Thereby, the crown land portion 13 is provided between the first middle land portion 12 and the second middle land portion 14. The crown land portion 13 of the present embodiment is provided on the tire equator C.

[0027] Each land portion 4 of the present embodiment is provided with sipes 16. In this specification, a "sipe" is a cut element having a minute width, and refers to one in which the width between two sipe walls in the main body portion of the sipe 16 is 1.5 mm or less. The width of the sipe 16 is desirably 0.2 to 1.2 mm, and more desirably 0.5 to 1.0 mm. The sipe 16 may include a widened portion that opens with a width larger than the above width, or a flask bottom portion having a width larger than the above width.

[0028] Figure 2 shows an enlarged view of the ground contact surface shape of the tread portion 2 when it contacts the ground. As shown in Figure 2, in the 50% load state where it is rim-mounted on a standard rim at the standard internal pressure and loaded with 50% of the standard load and grounded on a flat surface at a camber angle of 0°, when the widths of the ground contact surfaces in the tire axial direction of the first shoulder land portion 11, the first middle land portion 12, the crown land portion 13, the second middle land portion 14, and the second shoulder land portion 15 are respectively W1s, W1m, Wc, W2m, and W2s, the following formula (1) is satisfied. In the present disclosure, by adopting the above configuration, the ride comfort and noise performance can be improved. The reason is speculated to be the following mechanism. W1s>W1m>Wc>W2m≧W2s…(1)

[0029] With the above configuration, in the tire 1 of the present disclosure, the rigidity of the land portions in the inner region of the vehicle of the tread portion 2 is relaxed, improving the ride comfort. At the same time, the impact noise when these land portions contact the ground is also relaxed, improving the noise performance. It is speculated that the tire of the present disclosure can improve the ride comfort and noise performance by the above mechanism.

[0030] Also, the tire 1 having the above configuration has a greater rigidity in the land portion closer to the first tread end T1. Therefore, even when the center of the ground contact surface moves toward the first tread end T1 side due to steering, the feel of steering is stable, and a cornering force is generated linearly with respect to the increase in the steering angle. Therefore, the tire 1 of the present disclosure can exhibit excellent steering stability.

[0031] Hereinafter, the more detailed configuration of the present embodiment will be described. Note that each configuration described below shows a specific aspect of the present embodiment. Therefore, it goes without saying that the present disclosure can exhibit the above-described effects even if it does not have the configuration described below. Also, even if any one of the configurations described below is applied alone to the tire of the present disclosure having the above-described features, an improvement in performance corresponding to each configuration can be expected. Furthermore, when several of the configurations described below are applied in combination, a combined improvement in performance corresponding to each configuration can be expected.

[0032] In the 50% load state, it is desirable that the width W1s in the tire axial direction of the contact surface of the first shoulder land portion 11 is 115% to 125% of the width Wc of the contact surface of the crown land portion 13 in the tire axial direction. Thereby, the rigidity of the first shoulder land portion 11 is optimized, and together with the above-described effects, the noise performance can also be improved.

[0033] From the same viewpoint, in the 50% load state, it is desirable that the width W1m in the tire axial direction of the contact surface of the first middle land portion 12 is 101% to 107% of the width Wc of the contact surface of the crown land portion 13 in the tire axial direction.

[0034] In the 50% load state, it is desirable that the width W2m in the tire axial direction of the contact surface of the second middle land portion 14 is 90% to 99% of the width Wc of the contact surface of the crown land portion 13 in the tire axial direction. Thereby, the noise performance during straight running is improved. Also, the vibration of the tire during straight running is less likely to be transmitted to the vehicle body side, and the riding comfort is also improved.

[0035] From the same viewpoint, in the 50% load state, it is desirable that the width W2s in the tire axial direction of the contact surface of the second shoulder land portion 15 is 90% to 99% of the width Wc of the contact surface of the crown land portion 13 in the tire axial direction.

[0036] As a more desirable aspect, in the present embodiment, in the 50% load state, the width W2m of the second middle land portion 14 is made the same as the width W2s of the second shoulder land portion 15. Thereby, the progress of wear of the second middle land portion 14 and the second shoulder land portion 15 becomes uniform, and the uneven wear resistance performance is improved.

[0037] FIG. 3 shows an enlarged view of the first shoulder land portion 11 and the first middle land portion 12. As shown in FIG. 3, only sipes are provided on the first shoulder land portion 11. Thereby, the rigidity of the first shoulder land portion 11 is increased. In the present embodiment, a plurality of first shoulder sipes 21 extending in the tire axial direction are provided on the first shoulder land portion 11.

[0038] The tire circumferential pitch length P1 of the first shoulder groove 21 is, for example, 100% to 130% of the tread width W3 in the tire axial direction of the first shoulder land portion 11. The tire circumferential pitch length of the two grooves is the distance parallel to the tire circumferential direction from the center position in the width direction of the cross section of one groove to the center position of the other groove. When the distance changes in the tire axial direction, the intermediate distance corresponds to the pitch length.

[0039] It is desirable that the first shoulder groove 21 communicates with at least the first shoulder circumferential groove 5. The first shoulder groove 21 of the present embodiment extends, for example, from the first shoulder circumferential groove 5 to the first tread end T1 and completely crosses the tread of the first shoulder land portion 11. However, the first shoulder groove 21 is not limited to such a mode and may have a break end within the first shoulder land portion 11.

[0040] The first shoulder groove 21 is inclined, for example, in a first direction (in each figure of this specification, it is diagonally upward to the right) with respect to the tire axial direction. The angle of the first shoulder groove 21 with respect to the tire axial direction is, for example, 5 to 35°. In a more desirable mode, the first shoulder groove 21 includes a portion where the angle with respect to the tire axial direction increases toward the second tread end T2 side. Such a first shoulder groove 21 can also exert frictional force in the tire axial direction.

[0041] The opening width W4 of the first shoulder groove 21 on the tread is, for example, 4.0 to 8.0 mm. Such a first shoulder groove 21 can improve the resistance to uneven wear performance.

[0042] FIG. 4 shows a cross-sectional view of the first shoulder sip 21 as a cross-sectional view taken along line A-A of FIG. 3. As shown in FIG. 4, the first shoulder sip 21 includes a main body portion 21a extending in the tire radial direction and a widened 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 the present embodiment, the width of the main body portion 21a is, for example, 0.5 to 1.5 mm.

[0043] The widened portion 21b of the first shoulder sip 21 includes an inclined surface 22 extending from the main body portion 21a to the tread surface. The inclined surface 22 of the present embodiment is planar and inclined at an angle θ1 of 50 to 70° with respect to the tire radial direction. Such a widened portion 21b allows the entire surface of the inclined surface 22 to come into contact with the ground when a large ground pressure acts on the land portion, thus reliably expanding the substantial contact area of the tread portion. Therefore, the handling stability and riding comfort are improved.

[0044] The depth d1 of the widened portion 21b of the first shoulder sip 21 is 10% to 30% of the maximum depth d3 of the first shoulder sip 21, and in a preferred embodiment, it is 0.5 to 2.0 mm. The maximum depth d3 of the first shoulder sip 21 is, for example, 70% to 100% of the depth of the circumferential groove 3.

[0045] The width W6 of the inclined surface 22 of the widened portion 21b of the first shoulder sip 21 (which is the width along the tread surface in the cross-section of the sip) is, for example, 2.0 to 4.0 mm.

[0046] FIG. 5 shows a cross-sectional view taken along line C-C of FIG. 3. As shown in FIG. 5, the first shoulder sip 21 includes a shallow bottom portion 23 with a locally raised bottom. The shallow bottom portion 23 of the present embodiment is provided, for example, at the communication portion with the first shoulder circumferential groove 5. The minimum depth d4 of the shallow bottom portion 23 of the first shoulder sip 21 is 40% to 60% of the maximum depth d3 of the first shoulder sip 21. The length L3 in the tire axial direction of the shallow bottom portion 23 is 10% to 30% of the width W3 in the tire axial direction of the first shoulder land portion 11 (shown in FIG. 3). Note that the length L3 of the shallow bottom portion 23 is measured, for example, at the central position in the height direction of the shallow bottom portion 23. The first shoulder sip 21 having such a shallow bottom portion 23 maintains the rigidity of the first shoulder land portion 11 and improves the handling stability.

[0047] As shown in FIG. 3, the first middle land portion 12 includes a first longitudinal edge 12a on the first tread end T1 side, a second longitudinal edge 12b on the second tread end T2 side, and a tread surface between the first longitudinal edge 12a and the second longitudinal edge 12b. Further, only sips are provided on the first middle land portion 12. Thereby, the rigidity of the first middle land portion 12 is increased. In the first middle land portion 12 of the present embodiment, a plurality of first middle sips 30 extending in the tire axial direction are provided. The opening width W5 of the first middle sip 30 on the tread surface is smaller than the opening width W4 of the first shoulder sip 21 on the tread surface, for example. Specifically, the opening width W5 of the first middle sip 30 is, for example, 2.0 to 6.0 mm. Further, the opening width W5 of the first middle sip 30 is 50% to 90% of the opening width W4 of the first shoulder sip 21. Such a first middle sip 30 can improve the resistance to uneven wear performance.

[0048] FIG. 6 shows a cross-sectional view taken along line B-B of FIG. 3 as a view showing a cross-section of the first middle sip 30. As shown in FIG. 6, the first middle sip 30 includes a main body portion 30a extending in the tire radial direction and a widened portion 30b that opens on the tread surface of the land portion and has a width larger than that of the main body portion 30a. In the present embodiment, the width of the main body portion 30a is, for example, 0.5 to 1.5 mm.

[0049] The widened portion 30b of the first middle sip 30 includes an inclined surface 25 extending from the main body portion 30a to the tread surface. The inclined surface 25 of the present embodiment is planar and inclined at an angle θ2 of 30 to 60° with respect to the tire radial direction.

[0050] The depth d2 of the widened portion 30b of the first middle sip 30 is 15% to 30% of the maximum depth d5 of the first middle sip 30. Also, the depth d2 of the widened portion 30b of the first middle sip 30 is, for example, 1.0 to 3.0 mm. In a more desirable aspect, the depth d1 (shown in FIG. 4) of the widened portion 21b of the first shoulder sip 21 is smaller than the depth d2 of the widened portion 30b of the first middle sip 30. The depth d1 of the widened portion 21b of the first shoulder sip 21 is 50% to 90% of the depth d2 of the widened portion 30b of the first middle sip 30, and preferably 60% to 80%.

[0051] The width W8 of the inclined surface 25 of the widened portion 30b of the first middle sip 30 (which is the width along the tread surface in the cross-section of the sip) is, for example, 1.0 to 3.0 mm.

[0052] As shown in FIG. 3, the first middle sip 30 includes an outer first middle sip 31 extending from the first longitudinal edge 12a and having a cut-off end 31a within the first middle land portion 12, and an inner first middle sip 32 extending from the second longitudinal edge 12b and having a cut-off end 32a within the first middle land portion 12.

[0053] The first middle sip 30 extends linearly in a plan view of the tread. Also, the first middle sip 30 is inclined in a first direction with respect to the tire axial direction. More specifically, each of the outer first middle sip 31 and the inner first middle sip 32 extends linearly in a plan view of the tread and is inclined in the first direction with respect to the tire axial direction.

[0054] The angles of the outer first middle rib 31 and the inner first middle rib 32 with respect to the tire axis direction are each desirably 20° or more, more desirably 25° or more, and desirably 45° or less, more desirably 40° or less. Such an outer first middle rib 31 and an inner first middle rib 32 provide frictional force in a well-balanced manner in the tire axis direction and the tire circumferential direction.

[0055] The angle difference between the outer first middle rib 31 and the inner first middle rib 32 is desirably 10° or less, more desirably 5° or less, and in this embodiment, they are arranged in parallel. Such an outer first middle rib 31 and an inner first middle rib 32 can suppress uneven wear of the first middle land portion 12.

[0056] The outer first middle rib 31 and the inner first middle rib 32 are each interrupted without crossing the center position of the first middle land portion 12 in the tire axis direction. The length La of the outer first middle rib 31 in the tire axis direction is 20% or more, more preferably 25% or more, and preferably 45% or less, more preferably 40% or less of the width W7 of the first middle land portion 12 in the tire axis direction. Similarly, the length Lc of the inner first middle rib 32 in the tire axis direction is 20% or more, more preferably 25% or more, and preferably 45% or less, more preferably 40% or less of the width W7 of the first middle land portion 12 in the tire axis direction. Such an outer first middle rib 31 and an inner first middle rib 32 can improve ride comfort and noise performance while maintaining handling stability.

[0057] It is desirable that the outer first middle sipe 31 and the inner first middle sipe 32 are displaced in the tire circumferential direction. Thus, in the present embodiment, in a tread plan view, a virtual region obtained by extending the outer first middle sipe 31 parallel to the tire axial direction does not overlap with the inner first middle sipe 32. Further, the break end 31a of the outer first middle sipe 31 and the break end 32a of the inner first middle sipe 32 are displaced in the tire circumferential direction. The distance Lb in the tire circumferential direction between the break end 31a of the outer first middle sipe 31 and the break end 32a of the inner first middle sipe 32 is, for example, 50% or less of one pitch length P2 in the tire circumferential direction of the first middle sipe 30, and preferably 25% to 40%. In a more desirable aspect, the distance Lb is within the range of the following formula (2). Thereby, the pitch sound of each sipe is likely to be whitened, and the noise performance is improved. Lb = 2La ± 1 (mm) … (2)

[0058] Note that one pitch length P2 of the first middle sipe 30 is, for example, 80% to 120% of one pitch length P1 of the first shoulder sipe 21, and in a more desirable aspect, these are the same.

[0059] In the present embodiment, the outer first middle sipe 31 communicates with the first shoulder circumferential groove 5. Further, in a tread plan view, the widened portion of the outer first middle sipe 31 overlaps with a region obtained by extending the widened portion 21b of the first shoulder sipe 21 along its length direction. Thereby, the outer first middle sipe 31 and the first shoulder sipe 21 cooperate to further improve the wet performance.

[0060] The first middle sip 30 has a constant depth in its longitudinal direction. More specifically, the outer first middle sip 31 and the inner first middle sip 32 each have a constant depth in their longitudinal directions. The depth of the inner first middle sip 32 is, for example, 70% to 100% of the depth of the circumferential groove 3. Also, the maximum depth of the outer first middle sip 31 is smaller than the maximum depth of the inner first middle sip 32. The maximum depth of the outer first middle sip 31 is 30% to 70% of the maximum depth of the inner first middle sip 32 and is desirably 1.0 to 2.5 mm in a desirable embodiment.

[0061] Note that the cross-sectional shape of the sip shown in FIG. 6 can be applied to the outer first middle sip 31 and the inner first middle sip 32, respectively. Such outer first middle sip 31 and inner first middle sip 32 white-noise the pitch sound of each sip to improve the noise performance and, at the same time, improve the ride comfort and handling stability in a well-balanced manner.

[0062] As shown in FIG. 3, for example, a first longitudinal sip 33 extending in the tire circumferential direction is provided in the first middle land portion 12. The first longitudinal sip 33 of the present embodiment extends continuously in the tire circumferential direction. Such a first longitudinal sip 33 provides a frictional force in the tire axial direction during wet running. Another embodiment of the first longitudinal sip 33 will be described later.

[0063] The first longitudinal sip 33 is provided, for example, in the central region when the first middle 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 sip 33 to the center position of the first middle land portion 12 in the tire axial direction is desirably 10% or less, more desirably 5% or less, of the width W7 of the first middle land portion 12 in the tire axial direction. Such an arrangement of the first longitudinal sip 33 can suppress uneven wear of the first middle land portion 12.

[0064] FIG. 7 shows a cross-sectional view taken along line D-D of FIG. 2. As shown in FIG. 7, the first longitudinal sip 33 is configured, for example, to have a constant width from the open end to the bottom.

[0065] Fig. 8 shows an enlarged view of the first middle land portion 12, the crown land portion 13, and the second middle land portion 14. As shown in Fig. 8, the crown land portion 13 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 middle 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.

[0066] The crown land portion 13 includes an outer ground contact surface 36 on the outer side of the tire equator C on the side of the first tread end T1 and an inner ground contact surface 37 on the inner side of the tire equator C on the side of the second tread end T2. In the present embodiment, when the widths of the outer ground contact surface 36 and the inner ground contact surface 37 in the tire axial direction are Wco and Wci, respectively, the following formula (3) is satisfied. Such a crown land portion 13 helps to improve the handling stability. Wco>Wci…(3)

[0067] The width Wco of the outer ground contact surface 36 in the tire axial direction is, for example, 51% - 60% of the width W9 of the ground contact surface of the crown land portion 13 in the tire axial direction, and preferably 51% - 55%. Thereby, while suppressing uneven wear of the crown land portion 13, the handling stability is improved.

[0068] Only sipes are provided in the crown land portion 13. Thereby, the rigidity of the crown land portion 13 is increased.

[0069] A plurality of crown sipes 40 inclined in a second direction (in each figure of the present specification, it is downward to the right) opposite to the first direction with respect to the tire axial direction are provided in the crown land portion 13. The crown sipes 40 of the present embodiment are inclined in the second direction and extend linearly. Such crown sipes 40 cooperate with the first middle sipes 30 to provide frictional force in multiple directions and improve the wet performance.

[0070] The tire circumferential one-pitch length P3 of the crown sipe 40 is, for example, 80% to 120% of the tire circumferential one-pitch length P2 (shown in FIG. 3) of the first middle sipe 30, and in this embodiment, they are made the same. Such an arrangement of the sipes improves the uneven wear resistance performance.

[0071] The angle of the crown sipe 40 with respect to the tire axial direction is desirably 20° or more, more desirably 25° or more, and desirably 45° or less, more desirably 40° or less. The crown sipe 40 provides frictional force well-balanced in the tire circumferential direction and the tire axial direction.

[0072] The crown sipe 40 includes an outer crown sipe 41 extending from the first longitudinal edge 40a and having a cut-off end 41a in the crown land portion 13, and an inner crown sipe 42 extending from the second longitudinal edge 40b and having a cut-off end 42a in the crown land portion 13.

[0073] The angular difference between the outer crown sipe 41 and the inner crown sipe 42 is desirably 10° or less, more desirably 5° or less, and in this embodiment, they are arranged in parallel. Such outer crown sipe 41 and inner crown sipe 42 suppress the uneven wear of the crown land portion 13.

[0074] The outer crown sipe 41 and the inner crown sipe 42 are each cut off without crossing the center position of the crown land portion 13 in the tire axial direction. 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 sipe 41 and inner crown sipe 42 improve the handling stability and the riding comfort well-balanced.

[0075] The outer crown sipe 41 and the inner crown sipe 42 are preferably displaced in the tire circumferential direction. Thus, in the present embodiment, in a tread plan view, a virtual region obtained by extending the outer crown sipe 41 parallel to the tire axial direction does not overlap with the inner crown sipe 42. Further, the break end 41a of the outer crown sipe 41 and the break end 42a of the inner crown sipe 42 are displaced in the tire circumferential direction. The circumferential distance L6 between the break end 41a of the outer crown sipe 41 and the break end 42a of the inner crown sipe 42 is preferably smaller than, for example, the circumferential distance Lb between the break end 31a of the outer first middle sipe 31 and the break end 32a of the inner first middle sipe 32. Specifically, the distance L6 is desirably 70% or less, more desirably 60% or less, desirably 30% or more, and more desirably 40% or more of the distance Lb. Such an arrangement of the siping white-noises the pitch noise of each sipe and improves the noise performance.

[0076] The outer crown sipe 41 and the inner crown sipe 42 each have a constant depth in their longitudinal directions. The depth of the inner crown sipe 42 is, for example, 70% to 100% of the depth of the circumferential groove 3. Further, the maximum depth of the outer crown sipe 41 is smaller 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.

[0077] The cross-sectional shape configuration of the first middle sipe 30 described with reference to FIG. 6 can be applied to the outer crown sipe 41 and the inner crown sipe 42, respectively. Therefore, the description here is omitted.

[0078] Only siping is provided on the second middle land portion 14. Thereby, the rigidity of the second middle land portion 14 is increased.

[0079] The second middle land portion 14 is provided with a plurality of second middle sipes 45 inclined in the second direction with respect to the tire axial direction. The second middle sipes 45 of the present embodiment are inclined in the second direction and extend linearly.

[0080] The pitch length P4 in the tire circumferential direction of the second middle sipes 45 is, for example, 80% to 120% of the pitch length P3 in the tire circumferential direction of the crown sipes 40, and in the present embodiment, these are the same. Such an arrangement of the sipes improves the uneven wear resistance performance.

[0081] The angle of the second middle sipes 45 with respect to the tire axial direction is desirably 20° or more, more desirably 25° or more, and desirably 45° or less, more desirably 40° or less. Such second middle sipes 45 provide frictional force well-balanced in the tire circumferential direction and the tire axial direction.

[0082] The second middle sipes 45 include an outer second middle sipes 46 extending from the first longitudinal edge 14a and having a cut-off end 46a in the crown land portion 13, and an inner second middle sipes 47 extending from the second longitudinal edge 14b and having a cut-off end 47a in the crown land portion 13.

[0083] The angle difference between the outer second middle sipes 46 and the inner second middle sipes 47 is desirably 10° or less, more desirably 5° or less, and in the present embodiment, these are arranged in parallel. Such outer second middle sipes 46 and inner second middle sipes 47 suppress uneven wear of the second middle land portion 14.

[0084] The outer second middle groove 46 and the inner second middle groove 47 are each interrupted without crossing the center position of the second middle land portion 14 in the tire axial direction. The length L7 of the outer second middle groove 46 in the tire axial direction and the length L8 of the inner second middle groove 47 in the tire axial direction are, for example, larger than the length L4 of the outer crown groove 41 and the length L5 of the inner crown groove 42. Specifically, the length L7 of the outer second middle groove 46 and the length L8 of the inner second middle groove 47 are 25% to 35% of the width W10 of the second middle land portion 14 in the tire axial direction. Such outer second middle groove 46 and inner second middle groove 47 are helpful for improving wet performance and riding comfort.

[0085] It is desirable that the outer second middle groove 46 and the inner second middle groove 47 are displaced in the tire circumferential direction. Accordingly, in the present embodiment, in a plan view of the tread, the overlapping area between the virtual region obtained by extending the outer second middle groove 46 parallel to the tire axial direction and the inner second middle groove 47 is 10% or less of the opening area of the inner second middle groove 47. Also, the break end 46a of the outer second middle groove 46 and the break end 47a of the inner second middle groove 47 are displaced in the tire circumferential direction. The distance L9 in the tire circumferential direction between the break end 46a of the outer second middle groove 46 and the break end 47a of the inner second middle groove 47 is, for example, smaller than the distance Lb in the tire circumferential direction between the break end 31a of the outer first middle groove 31 and the break end 32a of the inner first middle groove 32, and preferably smaller than the distance L6 in the tire circumferential direction between the break end 41a of the outer crown groove 41 and the break end 42a of the inner crown groove 42. Specifically, the distance L9 is preferably 80% or less, more preferably 70% or less of the distance L6, and preferably 40% or more, more preferably 50% or more of the distance L6. Such an arrangement of the grooves optimizes the rigidity balance of each land portion and improves the handling stability and riding comfort in a well-balanced manner.

[0086] The outer second middle side 46 and the inner second middle side 47 each have a constant depth in their longitudinal directions. The depth of the inner second middle side 47 is, for example, 70% to 100% of the depth of the circumferential groove 3. Also, the maximum depth of the outer second middle side 46 is smaller than the maximum depth of the inner second middle side 47. The maximum depth of the outer second middle side 46 is 30% to 70% of the maximum depth of the inner second middle side 47, and in a preferred embodiment, it is 1.0 to 2.5 mm. Such an outer crown side 41 and an inner crown side 42 randomize the pitch sound of each side to improve the noise performance, and also improve the ride comfort and handling stability in a well-balanced manner.

[0087] The cross-sectional shape configuration of the first middle side 30 described in FIG. 6 can be applied to the outer second middle side 46 and the inner second middle side 47, respectively. Therefore, the description here is omitted.

[0088] The second middle land portion 14 is provided with, for example, a second longitudinal side 48 extending in the tire circumferential direction. The second longitudinal side 48 of the present embodiment extends continuously in the tire circumferential direction. Also, the second longitudinal side 48 has the same cross-sectional shape as the above-described first longitudinal side 33. Such a second longitudinal side 48 provides frictional force in the tire axial direction.

[0089] The second longitudinal side 48 is provided, for example, in the central region when the second middle land portion 14 is divided into three equal parts in the tire axial direction. The tire axial distance from the second longitudinal side 48 to the center position of the second middle land portion 14 in the tire axial direction is desirably 10% or less, more desirably 5% or less of the tire axial width W10 of the second middle land portion 14.

[0090] FIG. 9 shows an enlarged view of the second shoulder land portion 15 of FIG. 1. As shown in FIG. 9, only a side is provided on the second shoulder land portion 15. Thereby, the rigidity of the second middle land portion 14 is enhanced.

[0091] On the second shoulder land portion 15, for example, a plurality of second shoulder sipes 50 extending in the tire axial direction are provided. In the present embodiment, the total number of the second shoulder sipes 50 is larger than the total number of the first shoulder sipes 21 (shown in FIG. 3, and the same applies hereinafter). Such a sipe arrangement improves noise performance and wet performance.

[0092] In order to improve noise performance and wet performance while maintaining handling stability, the total number of the second shoulder sipes 50 is desirably 1.3 times or more, more desirably 1.5 times or more, and even more desirably 1.8 times or more, and desirably 2.8 times or less, more desirably 2.5 times or less, and even more desirably 2.2 times or less of the total number of the first shoulder sipes 21 (shown in FIG. 3).

[0093] The pitch length P5 in the tire circumferential direction of the second shoulder sipe 50 is, for example, 30% to 70% of the pitch length P4 in the tire circumferential direction of the second middle sipe 45 (shown in FIG. 8).

[0094] The second shoulder sipe 50 is inclined, for example, in the first direction. That is, the first shoulder sipe 21 (shown in FIG. 3, and the same applies hereinafter) and the second shoulder sipe 50 are inclined in the same direction with respect to the tire axial direction. The second shoulder sipe 50 of the present embodiment is inclined in the first direction and extends linearly.

[0095] The angle of the second shoulder sipe 50 with respect to the tire axial direction is, for example, 20° or less, desirably 15° or less, and more desirably 10° or less. Thus, in the present embodiment, the maximum angle of the first shoulder sipe 21 with respect to the tire axial direction is larger than the maximum angle of the second shoulder sipe 50 with respect to the tire axial direction. Such a sipe arrangement further improves noise performance.

[0096] The cross-sectional shape configuration of the first shoulder sipe 21 described with reference to FIG. 4 can be applied to the second shoulder sipe 50. Therefore, the description here is omitted.

[0097] The second shoulder rib 50 includes, for example, a transverse second shoulder rib 51 that completely crosses the second shoulder land portion 15 in the tire axial direction, and a discontinuous second shoulder rib 52 that extends in the tire axial direction from at least the second tread edge T2 and has a discontinuous end within the second shoulder land portion 15.

[0098] The discontinuous second shoulder rib 52 is longer in the tire axial direction than any of the first middle rib 30 (shown in FIG. 3), the crown rib 40, and the second middle rib 45 (shown in FIG. 8). The length L10 of the second shoulder rib 50 in the tire axial direction is desirably 50% or more, more desirably 60% or more, of the width W11 of the second shoulder land portion 15 in the tire axial direction, and desirably 90% or less, more desirably 80% or less. Such a discontinuous second shoulder rib 52 improves ride comfort and handling stability in a well-balanced manner.

[0099] FIG. 10 shows a cross-sectional view taken along line E-E of FIG. 9. As shown in FIG. 10, the transverse second shoulder rib 51 includes a shallow bottom portion 53 with a locally raised bottom. The shallow bottom portion 53 of the present embodiment is provided, for example, at the communication portion with the second shoulder circumferential groove 8. The configuration of the shallow bottom portion 23 of the first shoulder rib 21 (shown in FIG. 5) can be applied to the shallow bottom portion 53 of the second shoulder rib 50, and the description thereof is omitted here. The transverse second shoulder rib 51 including such a shallow bottom portion 53 maintains the rigidity of the second shoulder land portion 15 and improves handling stability.

[0100] As shown in FIG. 1, in the present embodiment, only the rib 16 is provided in each of the five land portions 4, and no transverse groove for drainage is provided. Thereby, the rigidity of each land portion is maintained, and since no pumping sound of the transverse groove is generated, an improvement in noise performance is expected.

[0101] Hereinafter, other embodiments of the present disclosure will be described. In the drawings showing other embodiments, the elements already described are given the same reference numerals as those described above, and the above-described configurations can be applied.

[0102] FIG. 11 shows an enlarged view of the first middle land portion 12 of another embodiment. As shown in FIG. 11, the first longitudinal sipes 33 provided in this first middle land portion 12 extend in a zigzag shape in the tire circumferential direction. The first longitudinal sipes 33 may, for example, extend in a wavy shape with a smooth curve. The amplitude amount A1 in the tire axial direction of this first longitudinal sipes 33 (which is the peak-to-peak value) is, for example, 1.0% to 8.0% of the width W7 in the tire axial direction of the first middle land portion 12. Further, the first longitudinal sipes 33 extend in a zigzag shape so as to have one cycle with respect to two pitches of the first middle sipes 30. Such first longitudinal sipes 33 can also provide frictional force in the tire circumferential direction.

[0103] FIG. 12 shows an enlarged view of the first middle land portion 12 of still another embodiment. As shown in FIG. 12, the first longitudinal sipes 33 provided in this first middle land portion 12 extend intermittently in the tire circumferential direction. That is, the first longitudinal sipes 33 are composed of a plurality of longitudinal sipes pieces 54 arranged in the tire circumferential direction. The length L11 in the tire circumferential direction of one longitudinal sipes piece 54 is, for example, 20% to 60% of the length P2 of one pitch in the tire circumferential direction of the first middle sipes 30. Such first longitudinal sipes 33 can provide frictional force in the tire axial direction while maintaining the rigidity of the first middle land portion 12.

[0104] The configuration of the first longitudinal sipes 33 shown in FIGS. 11 and 12 can also be applied to the second longitudinal sipes 48 provided in the second middle land portion 14.

[0105] Figures 13 and 14 show enlarged views of the first shoulder land portion 11 and the second shoulder land portion 15 of still other embodiments. In the first shoulder land portion 11 of the embodiment shown in FIG. 13, a plurality of first shoulder sipes 21 extending in a wavy shape are provided. This first shoulder sipe 21 is wavy and extends in the tire axial direction while oscillating in the tire circumferential direction in a tread plan view. Such a first shoulder sipe 21 can increase the rigidity of the land portion when the two sipe walls come into contact, and can improve the handling stability. Further, such a first shoulder sipe 21 can mitigate the impact acting on the edge during grounding and can suppress the noise during grounding as compared with a straight sipe.

[0106] The first shoulder sipe 21 of this embodiment extends, for example, from the first shoulder circumferential groove 5 to the first tread end T1. Further, the center of the amplitude of the first shoulder sipe 21 is inclined at an angle of 30° or less with respect to the tire axial direction. Such a first shoulder sipe 21 helps to improve the ride comfort and handling stability in a well-balanced manner.

[0107] In order to further enhance the above-described effects, a plurality of second shoulder sipes 50 extending in a wavy shape are provided in the second shoulder land portion 15 of this embodiment in a tread plan view. This second shoulder sipe 50 is wavy and extends in the tire axial direction while oscillating in the tire circumferential direction.

[0108] As a more desirable aspect, the second shoulder sipe 50 of this embodiment includes a transverse second shoulder sipe 51 extending from the second shoulder circumferential groove 8 to the second tread end T2, and an intermittent second shoulder sipe 52 extending from the second tread end T2 and interrupted within the second shoulder land portion 15. Further, the transverse second shoulder sipe 51 and the intermittent second shoulder sipe 52 are alternately provided in the tire circumferential direction. Thereby, the noise performance is improved while maintaining the handling stability.

[0109] In the first shoulder land portion 11 of the embodiment shown in FIG. 14, a first pair of sipes 56 is provided in which two first shoulder sipes 21 extending in a wave shape are arranged at a distance L12 of 6 to 12 mm in the tire axial direction. The first pair of sipes 56 is composed of, for example, a closed sipe 61 whose both ends are interrupted within the first shoulder land portion 11, and a semi-open sipe 62 that extends from the first shoulder circumferential groove 5 and is interrupted within the first shoulder land portion 11. Further, a plurality of such first pairs of sipes 56 are provided in the tire circumferential direction. The first shoulder land portion 11 provided with such first pairs of sipes 56 can improve noise performance and ride comfort while exhibiting excellent handling stability.

[0110] To further enhance the above-described effects, in the second shoulder land portion 15, a second pair of sipes 57 is provided in which two second shoulder sipes 50 extending in a wave shape are arranged at a distance L13 of 6 to 12 mm in the tire axial direction. The second pair of sipes 57 includes, for example, a closed sipe 63 whose both ends are interrupted within the second shoulder land portion 15, and a semi-open sipe 64 that extends from the second shoulder circumferential groove 8 and is interrupted within the second shoulder land portion 15. Further, the second pair of sipes 57 may include the closed sipe 63 and a tread end side sipe 65 that extends inward in the tire axial direction from at least the second tread end T2.

[0111] As shown in FIG. 13, the above-described first shoulder sipe 21 and second shoulder sipe 50 extending in a wave shape extend in a triangular wave shape that bends at an angle θ3 of 90 to 130°, for example. Further, the amplitude of this sipe is, for example, 1.0 to 1.6 mm.

[0112] The wavy sipe is not limited to the above-described aspect. For example, it may be a wave shape in which a plurality of semi-circles with a radius of 0.6 to 1.4 mm are connected in the tire axial direction. Further, in addition to such an aspect, various waveforms such as a sine wave, a rectangular wave, and a trapezoidal wave can be adopted for the wavy sipe.

[0113] The above-mentioned wavy shoulder sip may, as a more desirable embodiment, be configured as a so-called 3D sip that extends wavily in the sip length direction and the sip depth direction. Thereby, the above-mentioned effects can be further exerted. On the other hand, when such a shoulder sip is provided, it is desirable that each middle sip has two sip walls configured in a planar shape.

[0114] In addition, the wavy sips shown in FIGS. 13 and 14 do not include the above-mentioned widened portion and extend from the ground contact surface of the land portion to the bottom of the sip with a constant width. Thereby, the edge of the sip can exert a greater frictional force.

[0115] Hereinafter, still other embodiments of the present disclosure will be described. In the drawings showing the embodiments described below, elements already described are given the same reference numerals as those described above, and the above-described configuration can be applied.

[0116] FIG. 15 shows a developed view of the tread portion 2 of another embodiment. FIG. 16 shows an enlarged view of the first middle land portion 12, the crown land portion 13, and the second middle land portion 14 of the embodiment shown in FIG. 15. As shown in FIGS. 15 and 16, in this embodiment, mainly, the sips provided on each land portion are changed from the above-described embodiment. Note that also in this embodiment, the configuration already described can be applied to the width of each land portion.

[0117] As shown in FIG. 16, in this embodiment, each sip provided on the first middle land portion 12, the crown land portion 13, and the second middle land portion 14 is inclined in the same direction with respect to the tire axis direction, specifically, inclined in the first direction (rising to the upper right) with respect to the tire axis direction. The angle of each sip with respect to the tire axis direction is, for example, 10 to 30°. Such an arrangement of the sips can make the deformation of each land portion uniform when it contacts the ground, and thus the ground pressure acting on each land portion can be made uniform. Thereby, each land portion can cooperate to exert a large grip force.

[0118] In a desirable embodiment, in the first middle land portion 12, the crown land portion 13, and the second middle land portion 14, it is desirable that two sipes adjacent in the tire axial direction are arranged so as to be displaced in the tire circumferential direction. Further, for two sipes (that is, a pair consisting of the inner first middle sipe 32 and the outer crown sipe 41, or a pair consisting of the outer second middle sipe 46 and the inner crown sipe 42) adjacent in the tire axial direction via the first crown circumferential groove 6 or the second crown circumferential groove 7, it is also desirable that they are arranged so as to be displaced in the tire circumferential direction. Specifically, in a tread plan view, it is desirable that the two sipes are arranged such that the overlapping area between a virtual region obtained by extending one of the two sipes parallel to the tire axial direction and the other of the two sipes is 10% or less of the opening area of the other sipe. Thereby, the pitch sounds of the two sipes are less likely to overlap, and the noise performance is improved.

[0119] As shown in FIG. 15, in this embodiment, in a tread plan view, the outer first middle sipe 31 and the inner first middle sipe 32 provided in the first middle land portion 12, the outer crown sipe 41 and the inner crown sipe 42 provided in the crown land portion 13, and the outer second middle sipe 46 and the inner second middle sipe 47 provided in the second middle land portion 14 are arranged on a virtual belt 70 (dotted in FIG. 15) extending with a minute width. The virtual belt 70 is a virtual region extending with a constant width and inclined in the same direction as each sipe. In a desirable embodiment, the sipes are arranged such that the virtual belt 70 can have a width of 30 mm or less, more desirably 20 mm or less. Thereby, the grip performance and the noise performance are further improved.

[0120] As shown in FIG. 16, in this embodiment, the circumferential distance L14 of the outer first middle sip 31 between the cut ends 31a and the inner first middle sip 32 between the cut ends 32a, the circumferential distance L15 of the outer crown sip 41 between the cut ends 41a and the inner crown sip 42 between the cut ends 42a, and the circumferential distance L16 of the outer second middle sip 46 between the cut ends 46a and the inner second middle sip 47 between the cut ends 47a are preferably defined as appropriate. Similarly, the circumferential distance L17 of the end 32b on the first crown circumferential groove 6 side of the inner first middle sip 32 and the end 41b on the first crown circumferential groove 6 side of the outer crown sip 41, and the circumferential distance L18 of the end 46b on the second crown circumferential groove 7 side of the outer second middle sip 46 and the end 42b on the second crown circumferential groove 7 side of the inner crown sip 42 are preferably defined as appropriate. If these distances are large, the ground pressure acting on each land portion is likely to be uneven, and the grip performance may decrease. If these distances are small, the pitch sounds of each sip are likely to overlap, and the noise performance may decrease.

[0121] From such a perspective, the distance L14 is preferably 30% or more, more preferably 50% or more, and preferably 200% or less, more preferably 150% or less of the maximum circumferential length L19 of the outer first middle sip 31 or the inner first middle sip 32. Similarly, the distance L16 is preferably 30% or more, more preferably 50% or more, and preferably 200% or less, more preferably 150% or less of the maximum circumferential length L20 of the outer second middle sip 46 or the inner second middle sip 47. Thereby, the noise performance and the grip performance are improved in a well-balanced manner.

[0122] The distance L15 is desirably 100% or more, more desirably 150% or more, and desirably 300% or less, more desirably 250% or less of the maximum length L21 in the tire circumferential direction of the outer crown side 41 or the inner crown side 42. On the other hand, since a large contact pressure acts on the crown land portion 13, the arrangement of the sipes arranged in the crown land portion 13 has a great influence on various performances and is desirably defined more precisely. For this reason, in a more desirable aspect, the distance L15 is in the range of 200% ± 1.0 mm of the length L21.

[0123] The distance L17 is desirably 10% or more, more desirably 30% or more, and desirably 150% or less, more desirably 100% or less of the maximum length L22 in the tire circumferential direction of the inner first middle sipe 32 or the outer crown sipe 41. On the other hand, the distance L18 is desirably 50% or more, more desirably 100% or more, and desirably 250% or less, more desirably 200% or less of the maximum length L20 in the tire circumferential direction of the outer second middle sipe 46 or the inner crown sipe 42.

[0124] The outer first middle sipe 31 and the inner first middle sipe 32, and the outer second middle sipe 46 and the inner second middle sipe 47 of this embodiment have the same configuration as that shown in FIG. 6 in the sipe cross section. That is, as shown in FIG. 6, these sipes include a main body portion extending in the tire radial direction, and a widened portion that opens at the tread surface of the land portion and has a width larger than that of the main body portion. The widened portion includes an inclined surface extending from the main body portion to the tread surface. The above-described configuration can be applied to these.

[0125] As shown in Fig. 16, the outer first middle sipe 31 and the inner first middle sipe 32, as well as the outer second middle sipe 46 and the inner second middle sipe 47, have inclined surfaces arranged on the edges on both sides of the sipe. Further, each inclined surface is provided over the entire length direction of the sipe. Also, each inclined surface is wider toward the inside or outside in the tire axial direction. It is desirable that the width of each inclined surface continuously changes in the tire axial direction. However, it is not limited to such a mode, and the inclined surface may be arranged on a part of the sipe or may extend with a constant width.

[0126] Fig. 17 shows an enlarged view of the outer first middle sipe 31 and the inner first middle sipe 32 of Fig. 16. As shown in Fig. 17, in the inclined surface 31s of the outer first middle sipe 31, it is desirable that the width W12 at the end on the first longitudinal edge 12a side is larger than the width W13 at the end on the second longitudinal edge 12b side. The width W12 of the inclined surface 31s is, for example, 1.5 to 4.0 times the width W13. Also, in the inclined surface 32s of the inner first middle sipe 32, the width W14 at the end on the second longitudinal edge 12b side is larger than the width W15 at the end on the first longitudinal edge 12a side. The width W14 of the inclined surface 32s is, for example, 2.5 to 5.0 times the width W15. Thereby, the entire inclined surface of each sipe can be brought into contact with the ground, and a uniform ground pressure can be applied to the entire inclined surface. For this reason, excellent grip performance is exhibited. Note that each width of the inclined surface described above means the width of the inclined surface in the direction along the tread surface of the land portion in a cross section orthogonal to the length direction of the sipe.

[0127] It is desirable that the width W12 of the inclined surface 31s of the outer first middle sipe 31 is smaller than the width W14 of the inclined surface 32s of the inner first middle sipe 32. Specifically, the width W12 is 40% to 60% of the width W14. Thereby, a large inclined surface is formed on the second longitudinal edge 12b side where the ground pressure is relatively large, and the above-described effects can be surely obtained.

[0128] FIG. 18 shows an enlarged view of the outer second middle side 46 and the inner second middle side 47. As shown in FIG. 18, on the inclined surface 46s of the outer second middle side 46, it is desirable that the width W16 at the end on the first longitudinal edge 14a side is larger than the width W17 at the end on the second longitudinal edge 14b side. The width W16 of the inclined surface 46s is, for example, 2.5 to 5.0 times the width W17. Also, on the inclined surface 47s of the inner second middle side 47, the width W18 at the end on the second longitudinal edge 14b side is larger than the width W19 at the end on the first longitudinal edge 14a side. The width W18 of the inclined surface 47s is, for example, 1.5 to 4.0 times the width W19. Thereby, excellent grip performance is exhibited.

[0129] It is desirable that the width W18 of the inclined surface 47s of the inner second middle side 47 is smaller than the width W16 of the inclined surface 46s of the outer second middle side 46. Specifically, the width W18 is 40% to 60% of the width W16.

[0130] As shown in FIGS. 17 and 18, the maximum width of the inclined surface 31s of the outer first middle side 31 and the maximum width of the inclined surface 47s of the inner second middle side 47 are each desirably 0.5 to 2.5 mm. Also, the maximum depth of the inclined surface 31s of the outer first middle side 31 and the maximum depth of the inclined surface 47s of the inner second middle side 47 are each desirably 0.5 to 2.5 mm. The maximum width of the inclined surface 32s of the inner first middle side 32 and the maximum width of the inclined surface 46s of the outer second middle side 46 are each desirably 1.5 to 3.5 mm. Also, the maximum depth of the inclined surface 32s of the inner first middle side 32 and the maximum depth of the inclined surface 46s of the outer second middle side 46 are each desirably 1.5 to 3.5 mm. However, the dimensions of each inclined surface are not limited to such ranges.

[0131] In a more desirable aspect, it is desirable that the maximum depth of the inclined surface 32s of the inner first middle side 32 and the maximum depth of the inclined surface 46s of the outer second middle side 46 are greater than the maximum depth of the inclined surface 31s of the outer first middle side 31 and the maximum depth of the inclined surface 47s of the inner second middle side 47. Thereby, the grip performance is further improved.

[0132] As shown in FIG. 16, the outer crown side 41 and the inner crown side 42 are not provided with widened portions. That is, the outer crown side 41 and the inner crown side 42 of this embodiment have a cross-sectional shape as shown in FIG. 7 and are configured with a constant width from the open end to the bottom.

[0133] FIG. 19 shows an enlarged view of the first shoulder land portion 11 and the second shoulder land portion 15 of the embodiment shown in FIG. 15. As shown in FIG. 19, a plurality of first shoulder transverse grooves 28 and a plurality of first shoulder sides 21 are provided on the first shoulder land portion 11 of this embodiment.

[0134] The first shoulder transverse groove 28 extends, for example, from the first shoulder circumferential groove 5 to at least the first tread end T1. The first shoulder transverse groove 28 is inclined, for example, in the second direction with respect to the tire axial direction. The angle of the first shoulder transverse groove 28 with respect to the tire axial direction is, for example, 5 to 15°. Such a first shoulder transverse groove 28 helps to enhance wet performance.

[0135] The first shoulder sipe 21 is inclined, for example, in a second direction with respect to the tire axial direction. The first shoulder sipe 21 extends, for example, along the first shoulder lateral groove 28, and in a desirable embodiment, they are arranged in parallel. Also, the first shoulder sipe 21 of this embodiment extends, for example, from the first shoulder circumferential groove 5 and is interrupted within the first shoulder land 11. The axial length L24 of the first shoulder sipe 21 is, for example, 40% to 60% of the axial width W20 of the tread surface of the first shoulder land 11. Such a first shoulder sipe 21 helps to enhance ride comfort and noise performance in a well-balanced manner.

[0136] The first shoulder sipe 21 has a configuration similar to that shown in FIG. 6 in the sipe cross-section. That is, as shown in FIG. 6, the first shoulder sipe 21 includes a main body portion extending in the tire radial direction, and a widened portion that opens at the tread surface of the land and has a width larger than that of the main body portion. Further, the widened portion includes an inclined surface extending from the main body portion to the tread surface. The above-described configuration can be applied to these.

[0137] As shown in FIG. 19, in this embodiment, inclined surfaces 21s are arranged at the edges on both sides of the first shoulder sipe 21. Also, each inclined surface 21s is provided over the entire length direction of the first shoulder sipe 21. Further, the width of the inclined surface 21s of the first shoulder sipe 21 increases toward the inner side in the tire axial direction. The first shoulder sipe 21 having such inclined surfaces 21s helps to enhance grip performance.

[0138] The maximum width W21 of the inclined surface 21s of the first shoulder tread 21 is desirably greater than the width W12 (shown in FIG. 17) of the inclined surface 31s of the outer first middle tread 31 and smaller than the width W14 (shown in FIG. 17) of the inclined surface 32s of the inner first middle tread 32. Specifically, the width W21 of the inclined surface 21s of the first shoulder tread 21 is 60% to 90% of the width W14 of the inclined surface 32s of the inner first middle tread 32. Thereby, a uniform ground pressure is likely to act on the first shoulder land portion 11 and the first middle land portion 12 (shown in FIG. 15), and the grip performance is further improved.

[0139] In the second shoulder land portion 15 of this embodiment, a plurality of second shoulder transverse grooves 38 and a plurality of second shoulder treads 50 are provided. The second shoulder transverse grooves 38 and the second shoulder treads 50 are inclined in the second direction with respect to the tire axial direction, and in a desirable aspect, they are arranged in parallel.

[0140] The second shoulder transverse groove 38 extends at least inward in the tire axial direction from the second tread end T2 and is interrupted within the second shoulder land portion 15. The length L25 in the tire axial direction of the second shoulder transverse groove 38 is, for example, 60% to 90% of the width W22 in the tire axial direction of the tread surface of the second shoulder land portion 15.

[0141] The second shoulder tread 50 of this embodiment is not provided with a widened portion. That is, the second shoulder tread 50 of this embodiment has a cross-sectional shape as shown in FIG. 7 and is configured with a constant width from the open end to the bottom.

[0142] As shown in FIG. 19, the second shoulder rib 50 of this embodiment includes a transverse second shoulder rib 51 and a connecting second shoulder rib 55. The transverse second shoulder rib 51 completely traverses the second shoulder land portion 15 in the tire axial direction. The connecting second shoulder rib 55 extends from the break end 38a of the second shoulder lateral groove 38 to the second shoulder circumferential groove 8, connecting the second shoulder lateral groove 38 and the second shoulder circumferential groove 8. Such a second shoulder rib 50 helps to enhance the noise performance and riding comfort in a well - balanced manner.

[0143] In this embodiment, lateral grooves are provided in the first shoulder land portion 11 and the second shoulder land portion 15. However, instead of these lateral grooves, ribs may be provided. In this case, the pumping sound caused by the lateral grooves will not occur, and the noise performance will be further improved.

[0144] As described above, although the tire of one embodiment of the present disclosure has been described in detail, the present disclosure is not limited to the above - described specific embodiments and can be implemented with various modifications.

Example

[0145] A tire of size 235 / 55R19 having the basic pattern of FIG. 1 was prototyped based on the specifications in Tables 1 - 2. Also, as a reference tire for comparing noise performance (reference tire), a tire having the pattern shown in FIG. 20 was prototyped.

[0146] Each tread of this reference tire is provided with a pattern obtained by removing the widened portion from the sipe shown in Fig. 1. Further, in the reference tire, the width Wa of the first shoulder tread portion a and the width We of the second shoulder tread portion e are made the same. Also, the width Wb of the first middle tread portion b, the width Wc of the crown tread portion c, and the width Wd of the second middle tread portion d are made the same. Further, the widths Wa and We are larger than the widths Wb, Wc, and Wd. As a result, in the reference tire, in the 50% load-bearing state, when the widths of the tire axial direction contact ground surfaces of the first shoulder tread portion a, the first middle tread portion b, the crown tread portion c, the second middle tread portion d, and the second shoulder tread portion e are W1s, W1m, Wc, W2m, and W2s, respectively, the following formula (4) is satisfied. W1s = W2s > W1m = Wc = W2m…(4)

[0147] Also, as a comparative example, a tire having the pattern shown in Fig. 21 was prototyped. The tire of the comparative example has the same distribution of the widths of the tread portions as the reference tire, and widened portions are provided on each sipe in the same manner as in Fig. 1. The tire of the comparative example is substantially the same as that shown in Fig. 1 except for the above matters. The ride comfort and noise performance of each test tire were tested. The common specifications and test methods of each test tire are as follows. Mounting rim: 19×7.0J Tire internal pressure: 230 kPa Test vehicle: 2000 cc displacement, four-wheel drive vehicle Tire mounting position: all wheels

[0148] <Ride comfort> The ride comfort when driving on ordinary roads with the above test vehicle was evaluated by the driver's sensory evaluation. The result is a score with the ride comfort of the comparative example set as 100, and the larger the numerical value, the better the ride comfort.

[0149] <Noise performance> The test vehicle was driven on a dry road surface at speeds ranging from 40 to 100 km / h, and the maximum sound pressure of the noise inside the vehicle at this time was measured. The results are shown by an index in which the sound pressure reduction amount, which is the difference from the sound pressure of the reference tire, is set to 100 with respect to the sound pressure improvement amount of the comparative example. The larger this index, the smaller the maximum sound pressure of the noise, indicating that excellent noise performance is exhibited. The test results are shown in Tables 1 to 2.

[0150]

Table 1

[0151]

Table 2

[0152]

Table 3

[0153] As a result of the test, it was confirmed that the tires of the examples improved the ride comfort and noise performance.

[0154] [Appendix] This disclosure includes the following aspects.

[0155] [This Disclosure 1] A tire having a tread portion with a specified mounting direction on a vehicle, The tread portion includes a first tread end that becomes the outside of the vehicle when mounted on the vehicle, a second tread end that becomes the inside of the vehicle when mounted on the vehicle, four circumferential grooves that continuously extend in the circumferential direction of the tire between the first tread end and the second tread end, and five land portions divided by the circumferential grooves. Each of the five land portions is provided with sipes. The five land portions include a first shoulder land portion including the first tread end, a second shoulder land portion including the second tread end, a first middle land portion adjacent to the first shoulder land portion, a second middle land portion adjacent to the second shoulder land portion, and a crown land portion between the first middle land portion and the second middle land portion. In a 50% load-bearing state where the tire is mounted on a standard rim at a standard internal pressure and loaded with 50% of the standard load and grounded on a flat surface at a camber angle of 0°, when the widths of the ground contact surfaces of the first shoulder land portion, the first middle land portion, the crown land portion, the second middle land portion, and the second shoulder land portion in the tire axial direction are W1s, W1m, Wc, W2m, and W2s respectively, the following formula (1) is satisfied. Tire. W1s > W1m > Wc > W2m ≧ W2s …(1) [Disclosure 2] The tire according to Disclosure 1, wherein only the sipe is provided on each of the five land portions. [Disclosure 3] The first middle 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. A plurality of first middle sipers are provided on the first middle land portion. The tire according to Disclosure 1 or 2, wherein the first middle siper includes an outer first middle siper communicating with the first longitudinal edge and having a cut-off end within the first middle land portion, and an inner first middle siper communicating with the second longitudinal edge and having a cut-off end within the first middle land portion. [Disclosure 4] The tire according to Disclosure 3, wherein the cut-off end of the outer first middle siper and the cut-off end of the inner first middle siper are displaced in the tire circumferential direction. [Disclosure 5] The outer first middle siper extends linearly while being inclined with respect to the tire axial direction and has a length La in the tire axial direction. In the tire according to Disclosure 3 or 4 of the present disclosure, the distance Lb in the tire circumferential direction between the cut end of the outer first middle rib and the cut end of the inner first middle rib is within the range of the following formula (2). Lb = 2La ± 1 (mm)…(2) [Disclosure 6] In the tire according to any one of Disclosures 1 to 5 of the present disclosure, in the 50% load state, the width in the tire axial direction of the contact surface of the first shoulder land portion is 115% to 125% of the width of the contact surface of the crown land portion in the tire axial direction. [Disclosure 7] In the tire according to any one of Disclosures 1 to 6 of the present disclosure, in the 50% load state, the width in the tire axial direction of the contact surface of the second shoulder land portion is 90% to 99% of the width of the contact surface of the crown land portion in the tire axial direction. [Disclosure 8] A plurality of first shoulder ribs extending in a wave shape in a tread plan view are provided on the first shoulder land portion. In the tire according to any one of Disclosures 1 to 7 of the present disclosure, a plurality of second shoulder ribs extending in a wave shape in a tread plan view are provided on the second shoulder land portion. [Disclosure 9] In the tire according to Disclosure 8 of the present disclosure, the first shoulder rib and the second shoulder rib each extend in a wave shape in the rib depth direction. [Disclosure 10] A plurality of first middle ribs are provided on the first middle land portion. A plurality of second middle ribs are provided on the second middle land portion. In the tire according to Disclosure 8 or 9 of the present disclosure, the first middle rib and the second middle rib each have two rib walls configured in a planar shape. [Disclosure 11] On the first shoulder land portion, a first rib pair in which two ribs extending in a wave shape are arranged at a distance of 6 to 12 mm in the tire axial direction is provided. The tire according to any one of Disclosures 1 to 10, wherein the second shoulder land portion is provided with a second sipe pair in which two sipes extending in a wave shape are arranged at a distance of 6 to 12 mm in the tire axial direction. [Disclosure 12] The first shoulder land portion is provided with a plurality of first shoulder sipes. The second shoulder land portion is provided with a plurality of second shoulder sipes. The tire according to any one of Disclosures 1 to 11, wherein a pitch length of the plurality of second shoulder sipes is smaller than a pitch length of the plurality of first shoulder sipes. [Disclosure 13] The second shoulder sipe includes a transverse second shoulder sipe that completely crosses the second shoulder land portion in the tire axial direction, and a discontinuous second shoulder sipe that extends in the tire axial direction from at least the second tread end and has a discontinuous end in the second shoulder land portion. The tire according to any one of Disclosures 1 to 12. [Disclosure 14] The four circumferential grooves include a first shoulder circumferential groove provided on the most first tread end side. The tire according to any one of Disclosures 1 to 13, wherein the first shoulder circumferential groove has the smallest groove width among the four circumferential grooves. [Disclosure 15] The four circumferential grooves include a first crown circumferential groove adjacent to the inner side in the tire axial direction of the first shoulder circumferential groove. The tire according to Disclosure 14, wherein the first crown circumferential groove has the second smallest groove width among the four circumferential grooves. [Disclosure 16] The first middle 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 middle land portion is provided with a plurality of first middle sipes. The first middle groove communicates with the first longitudinal edge and includes an outer first middle groove having a cut-off end within the first middle land portion, and an inner first middle groove that communicates with the second longitudinal edge and has a cut-off end within the first middle land portion. Each of the outer first middle groove and the inner first middle groove includes a main body portion extending in the tire radial direction, and a widened portion that opens at the tread surface of the first middle land portion and has a width larger than that of the main body portion. The widened portion includes an inclined surface extending from the main body portion to the tread surface, and the tire according to any one of Disclosures 1 to 15. [Disclosure 17] In the inclined surface of the outer first middle groove, the width at the end on the first longitudinal edge side is larger than the width at the end on the second longitudinal edge side. In the inclined surface of the inner first middle groove, the width at the end on the second longitudinal edge side is larger than the width at the end on the first longitudinal edge side, and the tire according to Disclosure 16. [Disclosure 18] In the inclined surface of the outer first middle groove, the width at the end on the first longitudinal edge side is smaller than the width at the end on the second longitudinal edge side of the inclined surface of the inner first middle groove, and the tire according to Disclosure 16 or 17. [Disclosure 19] In the inclined surface of the outer first middle groove, the width at the end on the first longitudinal edge side is 40% to 60% of the width at the end on the second longitudinal edge side of the inclined surface of the inner first middle groove, and the tire according to Disclosure 18. [Disclosure 20] A plurality of first shoulder grooves extending in the tire axial direction are provided in the first shoulder land portion. The first shoulder groove includes a main body portion extending in the tire radial direction, and a widened portion that opens at the tread surface of the first shoulder land portion and has a width larger than that of the main body portion. The widened portion of the first shoulder groove includes an inclined surface extending from the main body portion to the tread surface. The width of the inclined surface of the first shoulder land is increasing toward the inner side in the tire axial direction, the tire according to any one of Disclosures 1 to 19 of the present disclosure.

Explanation of Signs

[0156] 2 Tread portion 3 Circumferential groove 4 Land portion 11 First shoulder land portion 12 First middle land portion 13 Crown land portion 14 Second middle land portion 15 Second shoulder land portion 16 Siping T1 First tread end T2 Second tread end

Claims

1. A tire having a tread portion with a specified mounting orientation on a vehicle, wherein the tread portion includes a first tread edge that becomes the outside of the vehicle when mounted on the vehicle, a second tread edge that becomes the inside of the vehicle when mounted on the vehicle, four circumferential grooves continuously extending in the tire circumferential direction between the first tread edge and the second tread edge, and five land portions divided by the circumferential grooves, wherein each of the five land portions is provided with a sipe, the five land portions include a first shoulder land portion including the first tread edge, a second shoulder land portion including the second tread edge, a first middle land portion adjacent to the first shoulder land portion, a second middle land portion adjacent to the second shoulder land portion, and a crown land portion between the first middle land portion and the second middle land portion, in a 50% load-bearing state where the tire is rim-mounted on a regular rim at a regular internal pressure and is grounded on a flat surface at a camber angle of 0° while loading 50% of the regular load, when the widths of the tire axial-direction contact ground surfaces of the first shoulder land portion, the first middle land portion, the crown land portion, the second middle land portion, and the second shoulder land portion are W1s, W1m, Wc, W2m, and W2s, respectively, satisfying the following formula (1), a tire. W1s > W1m > Wc > W2m ≧ W2s … (1)

2. The tire according to claim 1, wherein each of the five land portions is provided with only the sipe.

3. The first middle land portion includes a first longitudinal edge on the first tread edge side, a second longitudinal edge on the second tread edge side, and a tread surface between the first longitudinal edge and the second longitudinal edge, wherein a plurality of first middle sip es are provided in the first middle land portion, the first middle sipe includes an outer first middle sipe communicating with the first longitudinal edge and having a cut-off end in the first middle land portion, and an inner first middle sipe communicating with the second longitudinal edge and having a cut-off end in the first middle land portion, the tire according to claim 1 or 2.

4. The tire according to claim 3, wherein the cut-off end of the outer first middle sipe and the cut-off end of the inner first middle sipe are displaced in the tire circumferential direction.

5. The outer first middle sipe extends linearly while being inclined with respect to the tire axial direction and has a length La in the tire axial direction, The tire according to claim 3 or 4, wherein the distance Lb in the tire circumferential direction between the break end of the outer first middle rib and the break end of the inner first middle rib is within the range of the following formula (2). Lb = 2La ± 1 (mm)…(2)

6. The tire according to any one of claims 1 to 5, wherein in the 50% load state, the width in the tire axial direction of the contact surface of the first shoulder land portion is 115% to 125% of the width of the contact surface of the crown land portion in the tire axial direction.

7. The tire according to any one of claims 1 to 6, wherein in the 50% load state, the width in the tire axial direction of the contact surface of the second shoulder land portion is 90% to 99% of the width of the contact surface of the crown land portion in the tire axial direction.

8. A plurality of first shoulder ribs extending in a wave shape in a tread plan view are provided on the first shoulder land portion, The tire according to any one of claims 1 to 7, wherein a plurality of second shoulder ribs extending in a wave shape in a tread plan view are provided on the second shoulder land portion.

9. In the tire according to claim 8, the first shoulder rib and the second shoulder rib each extend in a wave shape in the rib depth direction.

10. A plurality of first middle ribs are provided on the first middle land portion, A plurality of second middle ribs are provided on the second middle land portion, In the tire according to claim 8 or 9, the first middle rib and the second middle rib each have two rib walls configured in a planar shape.

11. On the first shoulder land portion, a first rib pair in which two ribs extending in a wave shape are arranged at a distance of 6 to 12 mm in the tire axial direction is provided, The tire according to any one of claims 1 to 10, wherein on the second shoulder land portion, a second rib pair in which two ribs extending in a wave shape are arranged at a distance of 6 to 12 mm in the tire axial direction is provided.

12. A plurality of first shoulder ribs are provided on the first shoulder land portion, A plurality of second shoulder ribs are provided on the second shoulder land portion, The tire according to any one of claims 1 to 11, wherein the pitch length of the plurality of second shoulder ribs is smaller than the pitch length of the plurality of first shoulder ribs.

13. The second shoulder tread includes a transverse second shoulder tread that completely traverses the second shoulder land portion in the tire axial direction, and a discontinuous second shoulder tread that extends in the tire axial direction from at least the second tread edge and has a discontinuous end within the second shoulder land portion. The tire according to claim 12.

14. The four circumferential grooves include a first shoulder circumferential groove provided on the side closest to the first tread edge. The first shoulder circumferential groove has the smallest groove width among the four circumferential grooves. The tire according to any one of claims 1 to 13.

15. The four circumferential grooves include a first crown circumferential groove adjacent to the inner side of the first shoulder circumferential groove in the tire axial direction. The first crown circumferential groove has the second smallest groove width among the four circumferential grooves. The tire according to claim 14.

16. The first middle land portion includes a first longitudinal edge on the first tread edge side, a second longitudinal edge on the second tread edge side, and a tread surface between the first longitudinal edge and the second longitudinal edge. A plurality of first middle treads are provided on the first middle land portion. The first middle tread includes an outer first middle tread that communicates with the first longitudinal edge and has a discontinuous end within the first middle land portion, and an inner first middle tread that communicates with the second longitudinal edge and has a discontinuous end within the first middle land portion. Each of the outer first middle tread and the inner first middle tread includes a main body portion that extends in the tire radial direction, and a widened portion that opens at the tread surface of the first middle land portion and has a width larger than that of the main body portion. The widened portion includes an inclined surface that extends from the main body portion to the tread surface. The tire according to any one of claims 1 to 15.

17. On the inclined surface of the outer first middle tread, the width at the end on the first longitudinal edge side is larger than the width at the end on the second longitudinal edge side. On the inclined surface of the inner first middle tread, the width at the end on the second longitudinal edge side is larger than the width at the end on the first longitudinal edge side. The tire according to claim 16.

18. The width at the end on the first longitudinal edge side of the inclined surface of the outer first middle tread is smaller than the width at the end on the second longitudinal edge side of the inclined surface of the inner first middle tread. The tire according to claim 16 or 17.

19. The width at the end on the first longitudinal edge side of the inclined surface of the outer first middle side is 40% to 60% of the width at the end on the second longitudinal edge side of the inclined surface of the inner first middle side. The tire according to claim 18.

20. A plurality of first shoulder sipes extending in the tire axial direction are provided on the first shoulder land portion. The first shoulder sipe includes a main body portion extending in the tire radial direction, and a widened portion that opens at the tread surface of the first shoulder land portion and has a width larger than that of the main body portion. The widened portion of the first shoulder sipe includes an inclined surface extending from the main body portion to the tread surface. The width of the inclined surface of the first shoulder sipe increases toward the inner side in the tire axial direction. The tire according to any one of claims 1 to 19.

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