JP4776152B2 - Pneumatic tire - Google Patents

Description

  The present invention relates to a pneumatic tire having a directional pattern in which a rotational direction is specified, and more particularly to a pneumatic tire having both a high level of hydroplaning performance and handling stability among wet drainage performance. .

  In order to achieve both hydroplaning performance and driving stability on dry and wet road surfaces, it is common for the tread pattern to be a combination of circumferential grooves and inclined grooves, with the direction of rotation specified. Yes, in this type of tire, drainage in the front-rear direction of the tire is caused by circumferential grooves continuously extending in the tread circumferential direction, and drainage in the tire width direction is caused by inclined grooves extending inclined with respect to the tread circumferential direction. Are to be performed respectively.

However, in general, in such a tire, in order to improve drainage performance, the inclined groove is opened in the circumferential groove in the central region of the tread, so that uneven wear is caused in the acute-angled land portion sandwiched between the inclined groove and the circumferential groove. In addition, there is a problem that land rigidity in the central region of the tread is lowered.
On the other hand, as a technique for improving the hydroplaning performance without causing a decrease in the rigidity of the land portion in the central region of the tread, for example, there is one disclosed in JP-A-2001-225611.

  This tire has a tread pattern shown in a development view in FIG. Here, a pair of circumferential grooves 52 that are located symmetrically with respect to the tire equator line C and extend linearly in the tread circumferential direction are provided relatively close to each other in the central region of the tread tread portion 51. At the same time, another pair of circumferential grooves 53 are provided at a distance of about 1/4 of the tread width W from the tire equator line C on both sides of the tire equator line C. Between the circumferential grooves 52 and 53, The intermediate land portion 54 is partitioned. The intermediate land portion 54 is formed with a steeply inclined groove 55 and a gently inclined groove 56 that intersect with the circumferential groove 53 but does not open in the circumferential groove 52, and the steeply inclined groove 55 is formed substantially at the center of the intermediate land portion 54. It is bent and formed so as to be substantially parallel to the gently inclined groove 56 on the tread end side from the bending point, and each of the intermediate land portions 54 is partitioned with a substantially trapezoidal block 57 and a substantially comb-like rib 58. Yes. Further, a lateral groove 59 that opens from the circumferential groove 53 to the tread tread end is provided to partition the shoulder block 60, and the opening position of the lateral groove 59 to the circumferential groove 53 is an opening to the circumferential groove 53 of the gently inclined groove 56 every two rows. Match the position.

However, since the circumferential length of the block 57 having such a configuration is substantially the same as the circumferential length of the shoulder block 60, the circumferential length of the shoulder block 60 cannot be made too long in order to suppress pattern noise. Since the circumferential length of 57 cannot be increased, the degree of freedom cannot be secured when the circumferential rigidity needs to be further increased, which is a restrictive condition. Further, since the steeply inclined groove 55 is provided with a bending point, the drainage direction in the groove is shifted from the streamline direction in the tread ground surface at the bending point, and the drainage efficiency is likely to decrease. However, there was room for improvement in seeking higher drainage.
Japanese Patent Laid-Open No. 2001-225611

  An object of the present invention is to solve such problems of the prior art. The purpose of the present invention is to increase the circumferential rigidity of the block in the middle land and to improve the wet drainage performance, in particular, the resistance to water. The object is to provide a pneumatic tire with improved hydroplaning performance.

In the pneumatic tire according to the present invention, a pair of center circumferential grooves are formed on the tread tread surface portion and spaced apart from the tire equator line and continuously extending in the tread circumferential direction, and a center rib is defined therebetween. A pair of shoulder circumferential grooves extending continuously in the tread circumferential direction are formed between each center circumferential groove and the tread tread edge, and an intermediate land portion is formed between the shoulder circumferential groove and the center circumferential groove. A shoulder land is defined between the groove and the tread tread edge, and each intermediate land extends in a direction away from each other in a front view of the mounting posture of the tire on the vehicle. Respectively inclined grooves that open in the shoulder circumferential groove are formed at intervals in the tread circumferential direction, and each lateral groove that opens at the shoulder circumferential groove and the tread tread edge is spaced in the tread circumferential direction. There formed by forming a pneumatic tire having a specified directional pattern the direction of rotation,
Together to end the center side end of the gently slant groove in the middle land portion, loose from the end of the inclined groove, over the entire length, and Mashimashi loose extends at an angle smaller than the inclination groove to the shoulder circumferential groove side with respect to the circumferential direction, A steeply inclined groove that opens to the shoulder circumferential groove is formed at a position overlapping the opening of the gently inclined groove adjacent to the upper side or below the opening, and the intermediate land is formed by these both inclined grooves. The section is divided into a triangular block and a sawtooth rib continuous in the tread circumferential direction, and a corner of the rib sandwiched between a gently inclined groove and a steeply inclined groove formed in the vicinity of the shoulder circumferential groove. part of the surface height is gradually decreased toward the shoulder circumferential groove Rutotomoni, the opening position of the to shoulder circumferential groove of the lateral grooves and an opening position of the shoulder circumferential groove of the gently slant groove and steep grooves, lateral grooves two 1 in every 3 or 3 rows It is made by.

  According to this, by making the angle with respect to the tread circumferential direction of the steeply inclined groove smaller than that of the gently inclined groove over its entire length, the triangular shape defined by the steeply inclined groove, the gently inclined groove and the shoulder circumferential groove is formed. The tread circumferential length of the triangular block can be made longer than a substantially trapezoidal block partitioned by a steeply inclined groove having a bending point and a gently inclined groove as shown in FIG. The circumferential rigidity can be increased and high steering stability can be obtained. Also, by chamfering the corner formed in the vicinity of the shoulder circumferential groove of the rib defined by the center circumferential groove, the steeply inclined groove, and the gently inclined groove so that the rib height gradually decreases toward the shoulder circumferential groove. Further, it is possible to prevent the rigidity of the corner portion adjacent to the shoulder circumferential groove of the rib from being lowered, to enhance the uneven wear resistance and to improve the steering stability.

In addition, by providing the center circumferential groove and shoulder circumferential groove, the drainage performance in the tread circumferential direction is ensured, and by extending the steeply inclined groove more smoothly, the tread contact in the drainage direction in the steeply inclined groove is achieved. Deviation from the streamline direction in the ground can be prevented. In addition, the steeply inclined groove improves drainage performance from straight ahead to cornering, and the gently inclined groove has the effect of further improving drainage efficiency during cornering travel, effectively increasing drainage efficiency in all driving scenes. it can.
Here, by completing a steep slant groove and the gentle decline in both intermediate land portions each groove, due to be opened steep groove and gently slant groove in the center circumferential groove, in particular steep groove and the center circumferential groove It is possible to eliminate the definition of the sharp-angled land portion sandwiched between the steeply inclined groove and the gently inclined groove and the center circumferential groove, and to form a substantially serrated rib continuous in the tread circumferential direction. Therefore, it is possible to increase the rigidity of the intermediate land portion and improve the handling stability on both the dry road surface and the wet road surface.

Further, the gently inclined groove functions as an edge component on a road surface with low friction such as a wet road surface, and can improve driving and braking performance.
Further, by providing a lateral groove in the shoulder land portion, it is possible to improve hydroplaning performance during turning, and to improve driving and braking performance on a road surface with low friction such as a wet road surface.

Also, by opening both the steeply inclined groove and the gently inclined groove into the shoulder circumferential groove, the water in the central area of the tread can be effectively poured into the shoulder circumferential groove, and the lateral groove provided from the shoulder circumferential groove to the shoulder land portion. After passing through, it can be smoothly removed to the outside in the tread width direction.
Both the steeply inclined groove and the gently inclined groove form an acute angle with respect to the tread circumferential direction, so that the steeply inclined groove mainly contributes to drainage during straight running, and the gently inclined groove mainly drains during turning. Therefore, efficient drainage can be realized in all driving scenes, and higher wet drainage performance, especially hydroplaning performance can be obtained.

Here, preferably, at least a part of the gently inclined groove extends linearly.
Thereby, the resistance which a gentle inclination groove exerts on a drainage water flow can be reduced, and wet drainage performance can be improved.

Preferably, the steeply inclined groove is extended in a curved shape, and its angle with respect to the tread circumferential direction is gradually increased from the lower side to the upper side.
According to this, the steeply inclined groove has a smaller angle with respect to the tread circumferential direction in the central region of the tread, can increase the drainage flow rate, and gradually increases the angle toward the outer side in the tire width direction. Since the flow of water into the water can be made smooth, drainage efficiency can be increased, and wet drainage performance, particularly hydroplaning resistance can be enhanced.

  In addition, since the angle of the corner of the triangular block defined by the steeply inclined groove and the shoulder circumferential groove of the triangular block can be made relatively large, the rigidity of the corner of the triangular block can be increased, Steering stability on wet surfaces can be improved.

More preferably, the arrangement pitch number of the lateral grooves in the tread circumferential direction is 1.5 times or more and 3.0 or less than the arrangement pitch number of the gently inclined grooves in the tread circumferential direction.
According to this, the block defined by the lateral groove in the shoulder land portion can be made smaller than the block defined by the steeply inclined groove and the gently inclined groove in the intermediate land portion, and the impinging force on the road surface of the block can be reduced. By suppressing pattern noise and lowering the rigidity of the shoulder land portion, it is possible to improve the vibration ride comfort performance. In addition, by shortening the circumferential length of the shoulder land block, the height difference generated between the heel portion of the block and the toe portion of the adjacent block in the rear in the rotational direction is reduced as wear progresses. And the defect on the appearance of a tire can be controlled.
If the arrangement pitch number of the lateral grooves is less than 1.5 times the arrangement pitch number of the gently inclined grooves, the above effect is reduced, and if it is more than 3.0 times, the rigidity of the shoulder land block becomes too small. It is not preferable.

Preferably, the end of the gently inclined groove is positioned within a range of 3 to 50% of the width of the intermediate land portion from the edge on the tire equatorial plane side of the intermediate land portion.
According to this, the wet drainage performance, uneven wear resistance and steering stability performance in the tread central region can be improved in a well-balanced manner.
If the end of the gently sloping groove is located in a range smaller than 3% of the width of the middle land portion from the end of the middle land on the tire equatorial plane side, it will be partitioned between the center circumferential groove, the steeply sloping groove and the gently sloping groove. that the stiffness of the constricted portion of the saw-tooth-like ribs is reduced, uneven wear resistance and steering stability is deteriorated. In addition, if the end of the gently inclined groove is located in a range larger than 50% of the width of the intermediate land portion from the tire equator side end of the intermediate land portion, the drainage effect of the central region of the tread by the steeply inclined groove and the gently inclined groove is obtained. At the same time, the triangular block becomes too small, the rigidity becomes too small, and the steering stability performance deteriorates.

More preferably, the groove width of the shoulder circumferential groove is gradually narrowed from the opening position of the gently inclined groove to the opening position of the steeply inclined groove on the upper side thereof.
According to this, the water of the shoulder circumferential groove can be smoothly poured into the lateral groove of the shoulder land portion, the drainage efficiency can be enhanced, and the hydroplaning performance can be enhanced.

Preferably, in the vicinity of the end of the gently inclined groove near the center circumferential groove, the bottom of each of the gently inclined groove and the steeply inclined groove is a raised bottom inclined surface that gradually decreases the groove depth toward the end. together, of the rib, the lower portion than the end position of the gently slant groove, the lowest surface height in a portion corresponding to its end, while the height gradually increases toward the lower side, high toward the circumferential groove A beveled and inclined surface whose front view shape is substantially triangular is provided.

According to this, the rigidity of the rib defined between the center circumferential groove, the steeply inclined groove, and the gently inclined groove can be increased, and the uneven wear resistance and the steering stability performance in the tread central region can be improved. Moreover, drainage performance can be improved by smoothing the flow of water from the surface of the intermediate land portion to the steeply inclined groove and the gently inclined groove via the end of the steeply inclined groove.
In addition, by forming an inclined surface that bends toward the center circumferential groove from the end of the gently inclined groove, the groove volume of the center circumferential groove can be increased to improve wet drainage performance and hydroplaning performance, and the tread circumference The bent inclined surface that continues in the direction actively disturbs the air in the center circumferential groove, so that the generation of air column resonance noise in the center groove can be effectively suppressed.

More preferably, a chamfered inclined surface is provided to gradually reduce the surface height of the corner portion of the triangular block adjacent to the center circumferential groove toward the center circumferential groove, and the chamfered inclined surface is provided at the lowest position of the surface height. Continue to the raised bottom inclined surface.
According to this, the drainage performance is improved by further smoothing the flow of water from the surface of the intermediate land portion to the steeply inclined groove and the gently inclined groove via the end of the gently inclined groove, and is resistant to hydroplaning. The performance can be further enhanced.

Further preferably, the lowest position of the surface height of the chamfered inclined surface is made continuous with the intermediate position of the height of the raised bottom inclined surface.
According to this, the drainage performance is improved by further smoothing the flow of water from the surface of the intermediate land portion to the steeply inclined groove and the gently inclined groove via the end of the gently inclined groove, and is resistant to hydroplaning. The performance can be further enhanced.

Hereinafter, embodiments of the present invention will be described with reference to the drawings.
FIG. 1 is a development view of a tread pattern showing an embodiment of the present invention in a front view of a mounting posture on a vehicle.
Here, a pair of center circumferential grooves 2 that are located symmetrically across the tire equator line C and extend linearly in the tread circumferential direction are provided relatively close to each other on the tread surface 1. A center rib 3 is defined between the center circumferential grooves 2 and a pair of shoulder circumferential grooves 4 are provided on the both sides of the tire equator line C at a distance of about 1/4 of the tread width W. Furthermore, a shoulder land portion 5 is defined between the shoulder circumferential groove 4 and the tread tread surface end, and the shoulder land portion 5 is provided with a lateral groove 6 that communicates the shoulder circumferential groove 4 and the tread tread surface end.

An intermediate land portion 7 is defined between the center circumferential groove 2 and the shoulder circumferential groove 4, and the intermediate land portion 7 smoothly extends from the shoulder circumferential groove 4 with an acute angle α with respect to the tread circumferential direction. 2 and the end 9 of the gently inclined groove 8 and smoothly extend at an acute angle β smaller than the gently inclined groove 8 with respect to the circumferential direction of the tread over the entire length. And a steeply inclined groove 10 that opens slightly below the opening to the shoulder circumferential groove 4. The steeply inclined groove 10 is opened slightly below the opening position 11 of the gently inclined groove 8 adjacent to the upper side to the shoulder circumferential groove 4, so that the steeply inclined groove 10, the gently inclined groove 8, and the shoulder circumferential groove 4 Forms a zigzag-shaped groove continuous in the tread circumferential direction. Further, the gently inclined groove 8, the steeply inclined groove 10 and the shoulder circumferential groove 4 divide a substantially triangular triangular block 12 in the intermediate land portion 7, and the center circumferential groove 2, the gently inclined groove 8 and the steeply inclined groove 10. and allows to partition the saw tooth shaped rib 13 continuous in the tread circumferential direction, the ribs 13, the corner portion 14 of the surface height of the shoulder circumferential groove 4 side, chamfered so as to gradually decrease toward the shoulder circumferential groove 4 , A part thereof is protruded into the shoulder circumferential groove 4. The distance D from the side edge of the center circumferential groove 2 of the terminal end 9 of the gently inclined groove 8 is in the range of 3 to 50% of the width B of the intermediate land portion 7, and here, the terminal end 9 is positioned at approximately 10%.

Here, the steeply inclined groove 10 is extended in a curved shape, and the angle β with respect to the tread circumferential direction is gradually increased from the bottom to the top in a front view of the mounting posture of the tire on the vehicle.
Further, the gently inclined groove 8 is extended substantially linearly, and the angle α with respect to the tread circumferential direction is made substantially constant from below to above.

Further, the number of arrangement pitches in the tread circumferential direction of the lateral grooves 6 of the shoulder land portion 5 is 1.5 times or more, twice here the number of arrangement pitches in the tread circumferential direction of the gently inclined grooves 8, and the shoulder circumferential grooves of the lateral grooves 6 The lateral groove 6 and the gently inclined groove 8 are arranged so that the opening position to 4 and the opening position of the gently inclined groove 8 to the shoulder circumferential groove 4 coincide with each other in every two rows of the transverse grooves 6. In addition, the drain 14 in the shoulder circumferential groove 4 is guided to the lateral groove 6 of the shoulder land portion 5 by projecting the corner portion 14 formed on the shoulder circumferential groove 4 side of the rib into the shoulder circumferential groove 4. And drainage efficiency can be improved.
Further, the groove width of the shoulder circumferential groove 4 is gradually narrowed from the width G in the vicinity of the opening position 11 to the shoulder circumferential groove of the gently inclined groove 8 to the width H in the vicinity of the opening position of the steeply inclined groove. At the same time, the width G is returned to a position near the next opening position 11 and is periodically changed in the tread circumferential direction.

FIG. 2 is an enlarged cross-sectional view of the aa, bb, and cc sections of FIG.
As shown in FIGS. 1 and 2A, the groove bottom is raised so that the groove depth gradually decreases from the bottom of the gently inclined groove 8 and the steeply inclined groove 10 toward the end 9 of the gently inclined groove 8. As shown in FIGS. 1 and 2 (b), the front mounting shape of the tire mounted on the vehicle forms a substantially triangular raised bottom inclined surface 15, and is formed on the lower portion of the end 9 of the gently inclined groove 8 as shown in FIGS. The rib 13 is chamfered so that the surface height is the lowest at the portion corresponding to the terminal end, and the height gradually increases toward the lower side, while the height gradually decreases toward the center circumferential groove 2. A bent inclined surface 16 having a substantially triangular shape is formed. In addition, the triangular chamfered inclined surface 17 is formed by gradually decreasing the block surface height of the end portion of the triangular block on the center circumferential groove side, and the bottom of the steeply inclined groove 10 and the gently inclined groove 8 of the raised inclined surface 15 are formed. Is located above the lower end 18 of the triangular block, and the lowest position of the chamfered inclined surface 17 of the triangular block 12 is continued at the intermediate position of the raised bottom inclined surface 15. Thus, the raised bottom inclined surface 15 and the chamfered inclined surface 17 form a composite surface as shown in the sectional view of FIG. 2C and the perspective view of FIG. Thereby, drainage from the terminal end 9 of the gently inclined groove 8 to the steeply inclined groove 10 and the gently inclined groove 8 can be made smoother. Here, the raised bottom inclined surface 15, the bent inclined surface 16, and the chamfered inclined surface 17 are flat surfaces, but may be convex curved shapes.
Further, the upper end 19 and the lower end 20 facing the shoulder circumferential groove 4 of the triangular block 12 are also chamfered to increase the rigidity of the triangular block 12.

  By these things, each part rigidity of a triangular block and a rib can be improved, uneven wear resistance can be improved, and the steering stability at the time of dry and wet driving | running | working can be improved. Further, by providing a combination of steeply inclined grooves and gently inclined grooves having different angles with respect to the tread circumferential direction, more excellent wet drainage performance, in particular, hydroplaning performance can be obtained.

  Examples of the tire according to the present invention relating to anti-hydroplaning performance and steering stability performance will be described below.

As test tires, the size was PSR205 / 55 R16, and one type of example tire and two types of comparative tires were prepared. Example tire 1 has the tread pattern shown in FIG. 1 and the dimensions shown in Table 1.
Further, the comparative example tire 1 has the tread pattern shown in FIG. 5 and has the dimensions shown in Table 2, and the comparative example tire 2 has the tread pattern shown in FIG. It has dimensions. The reference numerals shown in Table 1 correspond to those in FIGS. 1 and 4, and the tread pattern shown in FIG. 4 is an end portion 14 facing the shoulder circumferential groove 4 of the rib 13 of the tread pattern shown in FIG. 1. The shape is not chamfered.

  The rim is assembled to the standard rim specified by JATMA of the test tire, the filling air pressure is 230 kPa, and the vehicle is run with a load equivalent to a two-person ride. The critical speed of hydroplaning phenomenon when passing through a 5mm wet road surface by straight running is determined by feeling evaluation, and the hydroplaning resistance at the time of curve passes through a wet road surface with a radius of 80m and a water depth of 5mm. The hydroplaning phenomenon occurrence limit lateral G is obtained by evaluating the feeling, and the steering stability performance is determined by the test driver when driving in a variety of driving modes on dry and wet circuit courses. Obtained by feeling evaluation and the results are shown in a table. It shows with the index on. In addition, the larger the index value in Table 3, the better the result.

According to the results shown in Table 3 , it can be seen that the example tire 1 exceeds the performance of the conventional comparative tires 1 and 2 in all measurement items of the hydroplaning resistance performance and the steering stability performance.
Comparing the comparative tire 1 and the comparative tire 2, the comparative tire 2 has improved hydroplaning performance compared to the comparative tire, but does not chamfer the corners facing the shoulder circumferential groove side of the rib. This shows that the rigidity of the block is lowered and the dry and wet steering stability is lowered.

It is an expanded view of the tread pattern which shows embodiment of this invention. It is a partial expanded sectional view of FIG. FIG. 2 is a partially enlarged perspective view of FIG. 1. It is a development view of a conventional tread pattern. It is a development view of a conventional tread pattern.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Tread surface part 2 Center circumferential groove 3 Center rib 4 Shoulder circumferential groove 5 Shoulder land part 6 Lateral groove 7 Intermediate land part 8 Slightly inclined groove 9 Terminal 10 Steeply inclined groove 11 Opening position 12 Triangle block 13 Rib 14 Corner part 15 Raised bottom inclined surface 16 Bending inclined surface 17 Chamfered inclined surface 18 Lower end 19 Upper end 20 Lower end 21 Opening position 22 Opening position 23 Tapered surface

Claims (9)

A pair of center circumferential grooves are formed in the tread tread portion that are located across the tire equator line and extend continuously in the tread circumferential direction, and a center rib is defined between them, and each center circumferential groove and the tread tread end A pair of shoulder circumferential grooves extending continuously in the tread circumferential direction are formed between the intermediate circumferential portion between the shoulder circumferential groove and the center circumferential groove, and between the shoulder circumferential groove and the tread tread edge. Each shoulder land section is divided, and each middle land section extends in a direction away from each other upward in a front view of the mounting posture of the tire on the vehicle, and opens to the shoulder circumferential groove. an inclined groove is formed at intervals in the tread circumferential direction, the shoulder land portion, obtained by forming at intervals each of lateral grooves opened to the shoulder circumferential groove and the tread end to the tread circumferential direction, the direction of rotation A pneumatic tire having a boss was directivity patterns,
Together to end the center side end of the gently slant groove in the middle land portion, loose from the end of the inclined groove, over the entire length, and Mashimashi loose extends at an angle smaller than the inclination groove to the shoulder circumferential groove side with respect to the circumferential direction, A steeply inclined groove that opens to the shoulder circumferential groove is formed at a position overlapping the opening of the gently inclined groove adjacent to the upper side or below the opening, and the intermediate land is formed by these both inclined grooves. The section is divided into a triangular block and a sawtooth rib continuous in the tread circumferential direction, and the surface height of the corner formed in the vicinity of the shoulder circumferential groove of the rib is directed to the shoulder circumferential groove. decreasing the allowed Rutotomoni, the opening position of the to shoulder circumferential groove of the lateral grooves, gently slant groove and the opening position of the shoulder circumferential groove steep groove, pneumatic made to match every two rows or three rows of lateral grooves tire.   The pneumatic tire according to claim 1, wherein at least a part of the gently inclined groove extends linearly.   The pneumatic tire according to claim 1 or 2, wherein the steeply inclined groove extends in a curved shape, and its angle with respect to the tread circumferential direction is gradually increased from the lower side to the upper side. The pneumatic according to any one of claims 1 to 3, wherein the end of the gently inclined groove is located in the range of 3 to 50% of the width of the intermediate land portion from the edge on the tire equatorial plane side of the intermediate land portion. tire. The width of the shoulder circumferential groove is gradually narrowed from an opening position of the gently inclined groove to an opening position of the steeply inclined groove on the upper side thereof. The pneumatic tire according to any one of the above. In the vicinity of the end of the gently inclined groove, the groove bottom of each of the gently inclined groove and the steeply inclined groove is a raised bottom inclined surface that gradually decreases the groove depth toward the end, and the gently inclined groove of the rib The shape of the front view in which the surface height is the lowest at the portion corresponding to the end of the groove from the end position of the groove, and the height gradually increases toward the lower side, while the height gradually decreases toward the circumferential groove. The pneumatic tire according to any one of claims 1 to 5, wherein a bent inclined surface having a substantially triangular shape is provided. A chamfered inclined surface is provided to gradually reduce the surface height of the corner of the triangular block adjacent to the center circumferential groove toward the center circumferential groove, and this chamfered inclined surface is formed on the raised bottom inclined surface at the lowest position of the surface height. The pneumatic tire according to claim 6, which is made continuous. The pneumatic tire according to claim 7, wherein a minimum position of the surface height of the chamfered inclined surface is made continuous with an intermediate position of the height of the raised bottom inclined surface. The steeply inclined groove is opened to the shoulder circumferential groove below the opening of the gently inclined groove adjacent to the upper side to the shoulder circumferential groove, and is sandwiched between these two inclined grooves, and on the shoulder circumferential groove side of the rib The pneumatic tire according to any one of claims 1 to 8, wherein the formed corner is protruded into the shoulder circumferential groove.

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