JP7631799B2 - tire - Google Patents

Description

The present invention relates to a tire.

Patent Document 1 below proposes a pneumatic tire whose tread portion is composed of four land portions in the tire axial direction. This pneumatic tire has lateral grooves and sipes that extend at an angle to the tire equator and sipes that extend in the tire circumferential direction in the center land portion on the center side of the tread portion. These lateral grooves and sipes improve the wet braking performance of this pneumatic tire while maintaining the steering stability performance.

JP 2013-139194 A

In recent years, as vehicles have become more powerful, there is a demand for tires with excellent cornering performance. Increasing the rigidity of each land portion is an effective way to improve cornering performance. However, this approach tends to increase the impact noise when the land portion touches the ground, impairing noise performance. In particular, tires with a four-rib structure tend to have a large axial width of each land portion, which can easily impair noise performance.

The present invention was devised in light of the above-mentioned circumstances, and its main objective is to improve cornering performance while maintaining noise performance, assuming a tire with a four-rib structure.

The present invention relates to a tire having a tread portion, the tread portion having a four-rib structure composed of three circumferential grooves extending continuously in the tire circumferential direction between a pair of tread ends and four land portions divided into the three circumferential grooves, the three circumferential grooves being a pair of shoulder circumferential grooves and one crown circumferential groove extending between the pair of shoulder circumferential grooves, the four land portions including a pair of shoulder land portions divided axially outward of the pair of shoulder circumferential grooves and a pair of crown land portions divided by the crown circumferential groove and the pair of shoulder circumferential grooves, at least one of the shoulder land portions being provided with a plurality of shoulder lateral grooves, a plurality of first shoulder sipes, and a plurality of second shoulder sipes. Each of the shoulder lateral grooves extends from at least the tread edge toward the axially inner side of the tire and has an interrupted end within the shoulder land portion, each of the first shoulder sipes extends from the interrupted end of each of the shoulder lateral grooves to the shoulder circumferential groove, each of the second shoulder sipes extends from at least the tread edge toward the axially inner side of the tire and has an interrupted end within the shoulder land portion, and each of the pair of crown land portions is provided with a plurality of first crown sipes of a fully open type, and each of the first crown sipes provided in one of the crown land portions is provided in a position continuous with each of the first shoulder sipes via the shoulder circumferential groove.

In the tire of the present invention, it is desirable that the axial length of each of the second shoulder sipes on the contact surface of the shoulder land portion is 30% to 70% of the axial width of the contact surface of the shoulder land portion.

In the tire of the present invention, it is desirable that the distance in the tire axial direction between the end of each of the second shoulder sipes and the end of each of the shoulder lateral grooves is 30% or less of the width in the tire axial direction of the contact surface of the shoulder land portion.

In the tire of the present invention, it is desirable that the maximum depth of the second shoulder sipes is smaller than the maximum depth of the first shoulder sipes.

In the tire of the present invention, the first shoulder sipe includes an inner portion on the shoulder circumferential groove side and an outer portion on the shoulder lateral groove side, and it is preferable that the depth of the inner portion is smaller than the depth of the outer portion.

In the tire of the present invention, it is desirable that the maximum depth of the second shoulder sipe is greater than the depth of the inner portion.

In the tire of the present invention, it is preferable that each of the first crown sipes provided in the other crown land portion is provided in a position that is not continuous with the first crown sipes provided in the one crown land portion via the crown circumferential groove.

By adopting the above configuration, the tire of the present invention can improve cornering performance while maintaining noise performance.

1 is a development view of a tread portion of a tire according to one embodiment of the present invention. FIG. 2 is an enlarged view of a pair of crown land portions of FIG. 1 . FIG. 2 is an enlarged view of a crown land portion and a shoulder land portion of FIG. 4 is a cross-sectional view taken along line AA in FIG. 3. FIG. 2 is an enlarged view of a shoulder land portion and a crown land portion of a comparative example tire.

Hereinafter, an embodiment of the present invention will be described with reference to the drawings.
Fig. 1 is a development view of a tread portion 2 of a tire 1 showing one embodiment of the present invention. As shown in Fig. 1, the tire 1 of this embodiment is suitably used as a pneumatic tire for passenger cars, for example. However, the present invention is not limited to such an embodiment.

As shown in FIG. 1, the tire 1 of the present invention has a tread portion 2 with a four-rib structure. That is, the tread portion 2 has three circumferential grooves 3 that extend continuously in the tire circumferential direction between a pair of tread ends Te, and four land portions 4 that are divided into the three circumferential grooves 3.

The tread end Te corresponds to the axially outermost contact point when the tire 1 is in a normal state, is loaded with a normal load, and is in contact with a flat surface with a camber angle of 0°.

In the case of pneumatic tires for which various standards are established, the "normal state" refers to a state in which the tire is mounted on a normal rim, inflated to the normal internal pressure, and unloaded. In the case of tires for which various standards are not established or non-pneumatic tires, the normal state refers to a standard usage state according to the intended use of the tire, in which the tire is not mounted on a vehicle and is unloaded. In this specification, unless otherwise specified, the dimensions of each part of the tire are values measured in the normal state.

A "genuine rim" is a rim that is specified for each tire by the standard system that includes the standard on which the tire is based. For example, in the case of JATMA, it is called a "standard rim," in the case of TRA, it is called a "design rim," and in the case of ETRTO, it is called a "measuring rim."

"Normal internal pressure" is the air pressure set for each tire by each standard in the standard system on which the tire is based. For JATMA, it is the "maximum air pressure." For TRA, it is the maximum value listed in the table "TIRE LOAD LIMITS AT VARIOUS COLD INFLATION PRESSURES." For ETRTO, it is the "INFLATION PRESSURE."

In the case of pneumatic tires for which various standards are established, the "normal load" is the load that is established for each tire in the standard system including the standards on which the tire is based, and is the "maximum load capacity" for JATMA, the maximum value listed in the table "TIRE LOAD LIMITS AT VARIOUS COLD INFLATION PRESSURES" for TRA, and "LOAD CAPACITY" for ETRTO. In addition, in the case of tires for which various standards are not established or non-pneumatic tires, the "normal load" refers to the load acting on a single tire in the standard mounting state of the tire. The "standard mounting state" refers to the state in which the tire is mounted on a standard vehicle corresponding to the intended use of the tire, and the vehicle is stationary on a flat road surface in a drivable state.

The three circumferential grooves 3 are composed of a pair of shoulder circumferential grooves 5 and one crown circumferential groove 6 extending between the pair of shoulder circumferential grooves 5. The pair of shoulder circumferential grooves 5 are provided so as to sandwich the tire equator C. The one crown circumferential groove 6 is provided, for example, on the tire equator C. In this embodiment, the circumferential grooves 3 extend, for example, in a straight line. Each circumferential groove 3 may extend in a wavy or zigzag pattern.

The axial distance L1 from the tire equator C to the groove centerline of the shoulder circumferential groove 5 is desirably, for example, 15% to 30% of the tread width TW. The tread width TW is the axial distance between the two tread ends Te in the normal state.

The groove width W1 of the circumferential groove 3 is desirably, for example, 4.0% to 8.0% of the tread width TW. The depth of the circumferential groove 3 is, for example, 5 to 12 mm in the case of a pneumatic tire for a passenger car.

The four land portions 4 are composed of a pair of shoulder land portions 7 and a pair of crown land portions 8. The shoulder land portions 7 are located axially outward of the shoulder circumferential grooves 5 and include the tread edge Te. The crown land portions 8 are located between the crown circumferential grooves 6 and the shoulder circumferential grooves 5.

Figure 2 shows an enlarged view of a pair of crown land portions 8. As shown in Figure 2, each of the pair of crown land portions 8 is provided with a plurality of fully open first crown sipes 11. A fully open sipe means a sipe that completely crosses the land portion in the tire axial direction. As a preferred embodiment, each of the pair of crown land portions 8 of this embodiment is provided with a plurality of crown lateral grooves 10 and a plurality of semi-open second crown sipes 12. A semi-open sipe means a sipe that does not completely cross the land portion and has an interrupted end within the land portion.

In this specification, a "sipe" refers to a cut element having a small width, with the width between two opposing inner walls being 1.5 mm or less. The width of the sipe is preferably 0.5 to 1.5 mm. Each sipe in this embodiment extends with a constant width from the opening to the bottom. However, this is not limited to this embodiment, and the opening of the sipe may be connected to a chamfered portion having a width of more than 1.5 mm. Also, the bottom of the sipe may be connected to a flask bottom having a width of more than 1.5 mm.

Figure 3 shows an enlarged view of the crown land portion 8 and the shoulder land portion 7. As shown in Figure 3, at least one of the shoulder land portions 7 has a plurality of shoulder lateral grooves 20, a plurality of first shoulder sipes 21, and a plurality of second shoulder sipes 22.

Each of the shoulder lateral grooves 20 extends axially inward from at least the tread edge Te and has an interrupted end 20a within the shoulder land portion 7. Each of the first shoulder sipes 21 extends from the interrupted end 20a of the shoulder lateral groove 20 to the shoulder circumferential groove 5. Each of the second shoulder sipes 22 extends axially inward from at least the tread edge Te and has an interrupted end 22a within the shoulder land portion 7.

In the present invention, each of the first crown sipes 11 provided in one crown land portion 8 is provided at a position that is continuous with the first shoulder sipe 21 via the shoulder circumferential groove 5. Note that "a sipe (first sipe) provided in one land portion and a sipe (second sipe) provided in the other land portion are continuous via a circumferential groove" includes a case in which a first virtual sipe obtained by extending the first sipe into the circumferential groove while maintaining its curvature and a second virtual sipe obtained by extending the second sipe into the circumferential groove while maintaining its curvature overlap in the circumferential groove, and also includes a case in which the minimum distance between the first virtual sipe and the second virtual sipe in the circumferential groove parallel to the tire circumferential direction is 3.0 mm or less. In addition, "a sipe (first sipe) provided on one land portion and a sipe (second sipe) provided on the other land portion are continuous via a circumferential groove" also includes a configuration in which the end (first end) of the first sipe on the circumferential groove side and the end (second end) of the second sipe on the circumferential groove side are arranged on the same tire axial line, and a configuration in which the distance in the tire circumferential direction between the first end and the second end is 3.0 mm or less.

In other words, the minimum distance parallel to the tire circumferential direction between the virtual sipe 31 (shown by a dot in FIG. 3) that extends the first shoulder sipe 21 into the shoulder circumferential groove 5 while maintaining its curvature, and the virtual sipe 32 (shown by a dot in FIG. 3) that extends the first crown sipe 11 into the shoulder circumferential groove 5 while maintaining its curvature, is 3.0 mm or less. In a more desirable embodiment, the virtual sipe 31 and the virtual sipe 32 extend substantially parallel to each other, and the minimum distance parallel to the tire circumferential direction is 2.0 mm or less.

By adopting the above configuration, the present invention can improve turning performance while maintaining noise performance. The following mechanism is believed to be the reason for this.

The shoulder land portion 7 provided with the above-mentioned grooves and sipes has an appropriate reduction in rigidity, and the impact noise when the tire touches the ground is suppressed. In addition, such a shoulder land portion 7 has small distortion of the contact surface, and the entire contact surface provides a large cornering force when steering.

In addition, the crown land portion 8 provided with the first crown sipes 11 has small distortion of the contact surface and provides a large cornering force. Moreover, in the present invention, the first shoulder sipes 21 and the first crown sipes 11 are provided in a position that is continuous with each other via the shoulder circumferential groove 5, so that the shoulder land portion 7 and the crown land portion 8 work together to provide a large cornering force and improve cornering performance. It is believed that the tire of the present invention can improve cornering performance while maintaining noise performance through the above mechanism.

The following describes the configuration of this embodiment in more detail. Each of the configurations described below represents a specific aspect of this embodiment. Therefore, it goes without saying that the present invention can achieve the above-mentioned effects even if it does not have the configurations described below. Furthermore, even if any one of the configurations described below is applied alone to a tire of the present invention having the above-mentioned characteristics, an improvement in performance corresponding to each configuration can be expected. Furthermore, when several of the configurations described below are applied in combination, a composite improvement in performance corresponding to each configuration can be expected.

As shown in FIG. 1, the tread portion 2 of this embodiment is point symmetrical with the center on the tire equator C, except that the arrangement pitch of each part is offset in the tire circumferential direction for the pattern between the tire equator C and one tread end Te and the pattern between the tire equator C and the other tread end Te. However, the tire 1 of the present invention is not limited to this aspect.

The maximum groove width W3 of the shoulder circumferential groove 5 is preferably smaller than the maximum groove width W2 of the crown circumferential groove 6. Specifically, the groove width W3 of the shoulder circumferential groove 5 is 60% to 80% of the groove width W2 of the crown circumferential groove 6. This provides steering stability on dry roads (hereinafter sometimes simply referred to as "steering stability").

The total width of the three circumferential grooves 3 is preferably 15% to 25% of the tread width TW. This provides a good balance between improved steering stability and wet performance.

As shown in FIG. 2, the crown lateral groove 10 extends from the shoulder circumferential groove 5 and has an interrupted end 10a within the crown land portion 8. The second crown sipe 12 extends from the interrupted end 10a of the crown lateral groove 10 toward the crown circumferential groove 6 and is interrupted within the crown land portion 8. Such crown lateral grooves 10 and second crown sipes 12 improve driving stability and wet performance in a well-balanced manner.

The groove width W4 of the crown lateral groove 10 is, for example, 50% to 90% of the maximum groove width W3 (shown in FIG. 1) of the shoulder circumferential groove 5, and preferably 55% to 75%.

The crown lateral groove 10 does not cross, for example, the axial center position of the crown land portion 8. In other words, the axial length L2 of the crown lateral groove 10 is 50% or less of the axial width W5 of the crown land portion 8, and preferably 35% to 45%. Such a crown lateral groove 10 can exhibit excellent drainage while maintaining the rigidity of the crown land portion 8.

The second crown sipes 12 are connected to the discontinuous ends 10a so as to be offset in the tire circumferential direction with respect to the groove center line 10c of the crown lateral groove 10 at the discontinuous ends 10a. In this embodiment, the second crown sipes 12 arranged in the crown land portion 8 on one side in the tire axial direction (left side in FIG. 2) are offset in the tire circumferential direction with respect to the groove center line 10c to one side (upper side in FIG. 2). In addition, the second crown sipes 12 arranged in the crown land portion 8 on the other side in the tire axial direction (right side in FIG. 2) are offset in the tire circumferential direction to the other side (lower side in FIG. 2) with respect to the groove center line 10c. Such an arrangement of the second crown sipes 12 helps to turn the impact sound of each crown land portion 8 when it touches the ground into white noise and improve noise performance.

The axial length L3 of the second crown sipe 12 is smaller than the axial length L2 of the crown lateral groove 10. Specifically, the length L3 of the second crown sipe 12 is 15% to 30% of the axial width W5 of the crown land portion 8. In a preferred embodiment, the second crown sipe 12 crosses the axial center position of the crown land portion 8. Such a second crown sipe 12 provides a large frictional force during wet driving while maintaining the rigidity of the crown land portion 8.

The distance L4 in the tire axial direction from the discontinuous end 12a of the second crown sipe 12 to the crown circumferential groove 6 is, for example, 25% to 40% of the axial width W5 of the crown land portion 8. The length L3 in the tire axial direction of the second crown sipe 12 is smaller than the distance L4. It is also desirable that no other grooves or sipes are provided in the area between the discontinuous end 12a and the crown circumferential groove 6. This reliably maintains the rigidity of the crown land portion 8, and provides excellent driving stability.

To further enhance the above-mentioned effect, it is desirable that the maximum depth of the second crown sipes 12 is smaller than the maximum depth of the crown lateral grooves 10 and smaller than the maximum depth of the first crown sipes 11. The maximum depth of the second crown sipes 12 is 85% to 95% of the maximum depth of the crown lateral grooves 10.

Each of the first crown sipes 11 provided in one crown land portion 8 is provided at a position that is not continuous with the first crown sipes 11 provided in the other crown land portion 8 via the crown circumferential groove 6. In other words, in this embodiment, the minimum distance parallel to the tire circumferential direction in the crown circumferential groove 6 between the virtual sipe 36 (shown by dots in FIG. 3) in which the first crown sipe 11 provided in one crown land portion 8 is extended into the crown circumferential groove 6 while maintaining its curvature, and the virtual sipe 37 (shown by dots in FIG. 3) in which the first crown sipe 11 provided in the other crown land portion 8 is extended into the crown circumferential groove 6 while maintaining its curvature, is greater than 3.0 mm. Such an arrangement of the first crown sipes 11 suppresses deformation of the crown land portion 8 near the tire equator C where a large ground pressure acts, improves initial responsiveness during steering, and improves cornering performance.

The tire circumferential distance L5 between the end of the first crown sipe 11 on one crown land portion 8 on the crown circumferential groove 6 side and the end of the first crown sipe 11 on the other crown land portion 8 on the crown circumferential groove 6 side is, for example, 25% to 50% of the tire circumferential pitch length P1 of the first crown sipe 11.

In plan view of the tread, it is desirable that the crown lateral grooves 10, the first crown sipes 11, and the second crown sipes 12 are each curved in an arc shape so as to be convex in the same circumferential direction of the tire. The radius of curvature of these sipes is, for example, 50 to 100 mm. This allows the entire crown land portion 8 to deform smoothly, and the cornering force tends to increase linearly in response to the amount of steering, improving cornering performance.

As shown in FIG. 3, although omitted in the figures of this specification, the shoulder lateral grooves 20 extend axially through the shoulder land portion 7 even in the region axially outboard of the tread edge Te.

It is desirable for the shoulder lateral groove 20 to cross the axial center position of the contact surface of the shoulder land portion 7. Specifically, the axial length L6 of the shoulder lateral groove 20 at the contact surface of the shoulder land portion 7 is 55% to 70% of the axial width W6 of the contact surface of the shoulder land portion 7. Such a shoulder lateral groove 20 improves steering stability and wet performance in a well-balanced manner.

It is desirable that the groove width of the shoulder lateral grooves 20 increases toward the axially outer side of the tire. It is desirable that the groove width W7 of the shoulder lateral grooves 20 at the tread end Te is greater than the groove width of the shoulder circumferential grooves 5 of the crown lateral grooves 10. Such shoulder lateral grooves 20 can exhibit excellent drainage properties.

The shoulder lateral groove 20 has a first groove edge 20e that is curved in an arc shape in a plan view of the tread. The angle of the first groove edge 20e with respect to the tire axial direction at the tread end Te is 5° or less. The radius of curvature of the first groove edge 20e is, for example, 150 to 250 mm. In this embodiment, the shoulder lateral groove 20 and the first crown sipe 11 are curved in an arc shape so as to be convex in the same direction in the tire circumferential direction. In a preferred embodiment, each of the first crown sipes 11 is curved in an arc shape with a smaller radius of curvature than the first groove edge of the shoulder lateral groove 20. As a result, the shoulder land portion 7 and the crown land portion 8 work together to provide a large cornering force, improving cornering performance.

The length L7 of the first shoulder sipe 21 in the axial direction of the tire at the contact surface of the shoulder land portion 7 is, for example, 25% to 40% of the width W6 in the axial direction of the tire at the contact surface of the shoulder land portion 7.

In a plan view of the tread, the first shoulder sipes 21 are curved in an arc shape so as to convex in the same direction as the shoulder lateral grooves 20. The first shoulder sipes 21 also extend along an imaginary extension line of the first groove edge 20e of the shoulder lateral groove 20. It is desirable that the first shoulder sipes 21 have the same or approximately the same radius of curvature as the first groove edge 20e of the shoulder lateral groove 20. Specifically, the radius of curvature of the first shoulder sipes is 90% to 110% of the radius of curvature of the first groove edge of the shoulder lateral groove 20.

Figure 4 shows a cross-sectional view of line A-A in Figure 3. As shown in Figure 4, the first shoulder sipe 21 includes an inner portion 26 on the shoulder circumferential groove 5 side and an outer portion 27 on the shoulder lateral groove 20 side. It is desirable that the depth d1 of the inner portion 26 is smaller than the depth d2 of the outer portion 27. The depth d1 of the inner portion 26 is 70% to 80% of the depth d2 of the outer portion 27. Such a first shoulder sipe 21 improves driving stability and wet performance in a well-balanced manner.

From a similar perspective, the axial length L8 of the inner portion 26 is, for example, 50% to 70% of the axial length L7 (shown in FIG. 3) of the first shoulder sipe 21. Note that, if the axial length of the inner portion 26 varies in the radial direction of the tire, the axial length is measured at the radial center position of the inner portion 26.

The maximum depth of the first shoulder sipe 21 (corresponding to the depth d2 of the outer portion 27 in this embodiment) is 90% to 110% of the maximum depth of the first crown sipe 11, and in a preferred embodiment, these depths are the same.

As shown in FIG. 3, in a more desirable embodiment, the length of the second crown sipe 12 is smaller than the axial length L7 of the first shoulder sipe 21. This increases the rigidity of the crown land portion 8 relatively, improving the initial response during cornering.

The second shoulder sipe 22 extends axially inward from at least the tread edge Te, and has an interrupted end 22a within the shoulder land portion 7. Although omitted in the figures of this specification, the second shoulder sipe 22 also extends axially through the shoulder land portion 7 in an area axially outboard of the tread edge Te.

From the perspective of achieving a good balance between improved steering stability and wet performance, the axial length L9 of each of the second shoulder sipes 22 on the contact surface of the shoulder land portion 7 is 30% to 70% of the axial width W6 of the contact surface of the shoulder land portion 7, and preferably 40% to 60%.

The axial distance L10 between each end 22a of the second shoulder sipes 22 and each end 20a of the shoulder lateral grooves 20 is preferably 30% or less of the axial width W6 of the contact surface of the shoulder land portion 7, and more preferably 20% or less. This allows the shoulder lateral grooves 20 and the second shoulder sipes 22 to work together to improve wet performance.

The second shoulder sipes 22 are curved in an arc shape so that they are convex in the same direction as the shoulder lateral grooves 20. In a preferred embodiment, the second shoulder sipes 22 extend along the first groove edge 20e of the shoulder lateral grooves 20, and in a more preferred embodiment, they are parallel. This allows the shoulder land portion 7 to deform smoothly, so that the entire land portion can exert a large cornering force.

The maximum depth of the second shoulder sipes 22 is preferably smaller than the maximum depth of the first shoulder sipes 21, for example. Also, the maximum depth of the second shoulder sipes 22 is preferably greater than the depth d1 (shown in FIG. 4) of the inner portion 26 of the first shoulder sipe 21. Such second shoulder sipes 22 are useful for improving wet performance.

The tire according to one embodiment of the present invention has been described in detail above, but the present invention is not limited to the specific embodiment described above and can be modified and implemented in various ways.

A pneumatic tire of size 195/65R15 having the basic pattern of FIG. 1 was prototyped based on the specifications of Table 1. As a comparative example, a tire having a shoulder land portion and a crown land portion as shown in FIG. 5 was prototyped. As shown in FIG. 5, in the comparative tire, the first shoulder sipe a and the first crown sipe b are provided in a position where they are not continuous. The comparative tire is substantially the same as the tire shown in FIG. 1 except for the above-mentioned points. The noise performance and cornering performance of each test tire were tested. The common specifications and test methods of each test tire are as follows.
Rim: 15 x 6.0J
Tire pressure: front wheel 230kPa, rear wheel 220kPa
Test vehicle: 1800cc displacement, front-wheel drive

<Noise performance>
The interior noise of the test vehicle was measured when it was driven on a dry road at a speed of 100 km/h. The results are expressed as an index with the reciprocal of the value of the comparative example being 100, and the larger the value, the lower the interior noise and the better the result.

<Turning performance>
The cornering performance of the test vehicle was evaluated by the driver when the vehicle was driven on a test course with a dry asphalt road surface. The results are expressed as a score based on the comparative example being 100, with a higher score indicating better cornering performance.
The test results are shown in Table 1.

The test results confirmed that the tire of the embodiment has improved cornering performance while maintaining noise performance.

Reference Signs List 2 tread portion 3 circumferential groove 4 land portion 5 shoulder circumferential groove 6 shoulder land portion 7 shoulder land portion 8 crown land portion 11 first crown sipe 20 shoulder lateral groove 20a discontinuous end 21 first shoulder sipe 22 second shoulder sipe Te tread end

Claims (6)

A tire having a tread portion,
The tread portion has a four-rib structure including three circumferential grooves extending continuously in the tire circumferential direction between a pair of tread ends and four land portions divided by the three circumferential grooves,
the three circumferential grooves are a pair of shoulder circumferential grooves and one crown circumferential groove extending between the pair of shoulder circumferential grooves,
the four land portions include a pair of shoulder land portions that are divided on tire axially outer sides of the pair of shoulder circumferential grooves, and a pair of crown land portions that are divided by the crown circumferential groove and the pair of shoulder circumferential grooves,
At least one of the shoulder land portions is provided with a plurality of shoulder lateral grooves, a plurality of first shoulder sipes, and a plurality of second shoulder sipes,
Each of the shoulder lateral grooves extends at least from the tread edge toward the axially inner side of the tire and has an interrupted end within the shoulder land portion,
Each of the first shoulder sipes extends from the interrupted end of each of the shoulder lateral grooves to the shoulder circumferential groove,
Each of the second shoulder sipes extends at least from the tread end toward the axially inner side of the tire and has an interrupted end within the shoulder land portion,
A plurality of first crown sipes of a fully open type are provided in each of the pair of crown land portions,
Each of the first crown sipes provided in one of the crown land portions is provided at a position continuous with each of the first shoulder sipes via the shoulder circumferential groove,
The maximum depth of the second shoulder sipe is smaller than the maximum depth of the first shoulder sipe .
tire. A tire having a tread portion,
The tread portion has a four-rib structure including three circumferential grooves extending continuously in the tire circumferential direction between a pair of tread ends and four land portions divided by the three circumferential grooves,
the three circumferential grooves are a pair of shoulder circumferential grooves and one crown circumferential groove extending between the pair of shoulder circumferential grooves,
the four land portions include a pair of shoulder land portions that are divided on tire axially outer sides of the pair of shoulder circumferential grooves, and a pair of crown land portions that are divided by the crown circumferential groove and the pair of shoulder circumferential grooves,
At least one of the shoulder land portions is provided with a plurality of shoulder lateral grooves, a plurality of first shoulder sipes, and a plurality of second shoulder sipes,
Each of the shoulder lateral grooves extends at least from the tread edge toward the axially inner side of the tire and has a discontinued end within the shoulder land portion,
Each of the first shoulder sipes extends from the interrupted end of each of the shoulder lateral grooves to the shoulder circumferential groove,
Each of the second shoulder sipes extends at least from the tread end toward the axially inner side of the tire and has an interrupted end within the shoulder land portion,
A plurality of first crown sipes of a fully open type are provided in each of the pair of crown land portions,
Each of the first crown sipes provided in one of the crown land portions is provided at a position continuous with each of the first shoulder sipes via the shoulder circumferential groove,
The first shoulder sipe includes an inner portion on the shoulder circumferential groove side and an outer portion on the shoulder lateral groove side,
The depth of the inner portion is less than the depth of the outer portion;
The maximum depth of the second shoulder sipe is greater than the depth of the inner portion.
tire. The tire of claim 2 , wherein a maximum depth of the second shoulder sipes is less than a maximum depth of the first shoulder sipes. The tire according to any one of claims 1 to 3, wherein the axial length of each of the second shoulder sipes in the contact surface of the shoulder land portion is 30% to 70% of the axial width of the contact surface of the shoulder land portion . 5. The tire according to claim 1, wherein a distance in the tire axial direction between the end of each of the second shoulder sipes and the end of each of the shoulder lateral grooves is 30% or less of a width in the tire axial direction of a contact surface of the shoulder land portion. 6. The tire according to claim 1, wherein each of the first crown sipes provided in the other crown land portion is provided in a position not continuous with the first crown sipe provided in the one crown land portion via the crown circumferential groove.

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