JP2006143138A - Pneumatic tire - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a pneumatic tire capable of balancing various kinds of performance at a high level such as steering stability performance, water drainage performance, low partial wear resistance performance, and the low noise performance. <P>SOLUTION: Chamfering to gradually increase a depth from the tread surface 110B of a tread 110 is applied to the extension of the terminating end 108A of a transverse main groove 108 (a recessed part 114 is formed). Then, the tread surface can maintain the drainage performance similar to a case that the transverse main groove is continuous from the terminating end of the transverse main groove to a farther part, and a deep part of the transverse main groove is continuous as a rib in the circumferential direction of a tire to secure the rigidity of a land part. Steering stability can be thus secured on either dry or wet road surfaces, and partial wear is prevented and noise is reduced. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to pneumatic tires, particularly in summer tires where balance of performance is important, steering stability performance when the road surface is dry, drainage performance when the road surface is wet, reduction of tire noise and uneven wear, The present invention relates to a pneumatic tire having a tread pattern capable of balancing contradictory performances in a high dimension.

In a conventional summer tire (balanced tire), a circumferential main groove formed linearly along the tire circumferential direction, a lateral groove formed in a direction intersecting the circumferential main groove, and parallel to the lateral groove A block pattern having a sipe is generally used (see, for example, Patent Document 1), and there is also a technique for chamfering the corner of the land portion of the tread in order to balance the various performances of the summer tire. (For example, refer to Patent Document 2).
JP 2002-240513 A JP 2000-264020 A

  However, in the case of the groove form in the conventional tread pattern, if the acute angle side inclination angle of the lateral groove with respect to the tire circumferential direction is set large for the purpose of preventing uneven wear, it will lead to deterioration of pattern noise and drainage, When trying to widen the width of the lateral groove for the purpose of ensuring the safety, there is a problem that it leads to further deterioration of pattern noise and steering stability due to a decrease in land part rigidity.

  In consideration of the above facts, an object of the present invention is to balance various performances such as steering stability performance, drainage performance, uneven wear resistance performance, and low noise performance at a high level.

  According to a first aspect of the present invention, there is provided a circumferential main groove formed on each side of the tire equatorial plane in the tread, and between the circumferential main grooves furthest from the tire equatorial plane on both sides of the tire equatorial plane. Intersecting the circumferential main groove and the central region land portion formed between the circumferential main groove furthest from the tire equator plane and the grounded end of the tread. A pneumatic tire provided with a plurality of horizontal main grooves extending in the direction and arranged in the tire circumferential direction, wherein at least one end of the horizontal main groove in the central region land portion is adjacent to the one end One groove in the transverse main groove is terminated in the circumferential main groove without opening directly, and in the region from the terminal end of the transverse main groove to the circumferential main groove adjacent to the terminal end. The part including the extension of the wall It is characterized in having a recessed portion depth from the tread surface of the tread is formed so as to gradually increased with the width toward the tire circumferential direction is gradually reduced.

  In the pneumatic tire according to claim 1, drainage performance (hydroplaning performance) which is a basic performance of the balanced tire can be ensured by forming at least two circumferential main grooves in the tread. In addition, by dividing the tread into a central region land part and an end region land part, the central region land part is responsible for steering stability performance and drainage performance, and the end region land part has uneven wear resistance and low noise performance, etc. It is possible to balance the various performances as a pneumatic tire by separating functions. Furthermore, by arranging a plurality of lateral main grooves in the tire circumferential direction, it is possible to ensure hydroplaning performance and braking performance when the road surface is wet.

  Further, at least one end of the lateral main groove is terminated without directly opening the circumferential main groove adjacent to the one end, and the one end portion is configured in a rib shape continuous in the tire circumferential direction. Thus, it is possible to ensure the rigidity of the land portion and improve the handling stability.

  Furthermore, by providing a recess (chamfering process) that gradually increases the depth from the tread surface on the extension line of the end of the horizontal main groove, the horizontal main groove extends further from the end of the horizontal main groove. The same drainage performance can be ensured on the tread as if the rim is continuous, and the bottom side portion of the recess between the terminal end of the lateral main groove and the circumferential main groove is in a continuous state as a rib in the tire circumferential direction. This ensures the rigidity of the land. Thereby, it is possible to ensure steering stability regardless of whether the road surface is dry or wet, and prevent uneven wear and reduce noise.

  Note that the shape of the recess when the tread is viewed in plan may be a substantially triangular shape that tapers as the depth increases.

  According to a second aspect of the present invention, in the pneumatic tire according to the first aspect, the opposite ends of the transverse main groove defined by the adjacent circumferential main grooves are opposite to each other.

  In the pneumatic tire according to claim 2, since the chamfering directions at the end portions of the horizontal main groove are opposite to each other, the drainage of the tread surface in the direction going down the dent portion. It is advantageous to contain noise in the direction of going up the dent.

  According to a third aspect of the present invention, in the pneumatic tire of the first aspect, both ends of the horizontal main groove defined by the adjacent circumferential main grooves are in the same direction.

  In the pneumatic tire according to the third aspect, since the inclining direction of the recess is the same at both end portions of the horizontal main groove, the wear form in the same groove can be made uniform. When the tread pattern is axisymmetric on both sides of the tire equator plane, drainage can be further improved by specifying the direction of rotation of the tire in the direction opposite to the inclination direction of the recess.

  According to a fourth aspect of the present invention, in the pneumatic tire according to any one of the first to third aspects, both ends of the lateral main groove in the central region land portion are the circumferential mains adjacent to the both ends. It terminates without opening directly into the groove, and the recess is formed at both end portions of the horizontal main groove.

  In the pneumatic tire according to claim 4, by providing chamfered dents at both ends of the horizontal main groove, the land portion rigidity is ensured while sacrificing drainage performance slightly, so uneven wear resistance performance, It is possible to improve steering stability performance and low noise performance.

  According to a fifth aspect of the present invention, in the pneumatic tire according to any one of the first to fourth aspects, the concave portion opens into the circumferential main groove adjacent to the concave portion. It is a feature.

  The reason why the recesses are opened in adjacent circumferential main grooves is to ensure drainage performance. For this reason, in the pneumatic tire according to claim 5, even when the water in the horizontal main groove reaches the terminal portion, the destination is not lost, and the water passes through the concave portion on the extension line of the horizontal main groove. It flows out to the direction main groove.

  According to a sixth aspect of the present invention, in the pneumatic tire according to any one of the first to fourth aspects, the recessed portion terminates without opening in the circumferential main groove adjacent to the recessed portion. In addition, a narrow rib continuous in the tire circumferential direction is formed between the recess and the circumferential main groove.

  In the pneumatic tire according to claim 6, since the narrow rib continuous in the tire circumferential direction is formed between the recess and the circumferential main groove, the drainage performance is slightly lowered, but the rigidity of the land portion is improved. As a result, steering stability is improved.

  According to a seventh aspect of the present invention, in the pneumatic tire according to the fourth aspect of the present invention, one of the recessed portions at the both end portions of the lateral main groove opens into the circumferential main groove adjacent to the recessed portion. A narrow rib continuous in the tire circumferential direction is formed between the recess and the circumferential main groove, and the other recess is adjacent to the circumferential main. It is characterized by opening in the groove.

  In the pneumatic tire according to claim 7, narrow ribs are formed on one of the recesses at both end portions of the horizontal main groove, and the other recess is opened in the circumferential main groove. Therefore, drainage performance is secured while improving the rigidity of the land and improving the handling stability.

  The invention according to claim 8 is the pneumatic tire according to claim 6 or 7, characterized in that the narrow rib is formed closer to the tire equatorial plane in the central region land portion.

  In the pneumatic tire according to claim 8, narrow ribs are provided closer to the tire equator plane in consideration of ensuring steering stability and ensuring drainage performance.

  The invention according to claim 9 is the pneumatic tire according to any one of claims 1 to 8, wherein the horizontal main groove in at least one of the end region land portions is formed in the end region land portion. It is characterized in that a narrow-width end rib that terminates without opening in the adjacent circumferential main groove and is continuous in the tire circumferential direction is formed between the terminal portion and the circumferential main groove.

  In the pneumatic tire according to claim 9, in consideration of uneven wear resistance, low noise performance, and the like, the lateral main groove is terminated in the middle without opening the circumferential main groove in the end region. It is said.

  The invention of claim 10 is the pneumatic tire according to claim 9, wherein the width of the narrow end rib is 10 to 95% of the width of the end region land portion where the narrow end rib is located. It is characterized by being.

  Here, regarding the width of the narrow end rib, the lower limit is set to 10% of the width of the end region land portion where the narrow end rib is located. Or because the length of the horizontal main groove is extended, the effectiveness with respect to uneven wear resistance and low noise performance is reduced, and the upper limit is 95%. This is because it leads to deterioration of drainage performance during cornering.

  The invention according to claim 11 is the pneumatic tire according to claim 9 or claim 10, wherein one groove wall of the transverse main groove is extended from the terminal portion of the transverse main groove in the end region land portion. A sipe is formed in a region up to the circumferential main groove adjacent to the terminal portion on the line.

  In the pneumatic tire according to the eleventh aspect, since the portion of the narrow end rib of the end region land portion is carved by sipe, the rigidity of the land portion is optimized and the riding comfort is improved.

  The invention according to claim 12 is the pneumatic tire according to any one of claims 1 to 11, wherein the circumferential main groove is adjacent to both sides in the width direction of the central region land portion in the circumferential direction of the end portion. It is composed of a main groove and two central circumferential main grooves formed in the central region land, and the central region land is defined by the two central circumferential grooves and is continuous in the tire circumferential direction. A first central region land portion, and a second central region land portion defined by the central circumferential main groove and the end circumferential main groove closest to the central circumferential main groove, 2 The dent is formed at the terminal end of the horizontal main groove in the land portion of the central region.

  In the pneumatic tire according to the twelfth aspect, since the first central land portion, that is, the structure of at least four grooves provided with the center rib is used, the drainage performance and the steering stability performance can be further improved. Moreover, since the recessed part is provided in the both ends of the horizontal main groove in the 2nd central land part, it becomes possible to improve the anti-wearing performance, the low noise performance, and the steering stability performance at the time of dry and wet in a well-balanced manner.

  According to a thirteenth aspect of the present invention, in the pneumatic tire according to any one of the first to twelfth aspects, an inclination angle on an acute angle side formed by the lateral main groove in the central region land portion and the tire circumferential direction is 15 to 80 °, and the inclination angle on the acute angle side formed by the lateral main groove and the tire circumferential direction in the end region land portion is 65 to 90 °.

  Here, with respect to the inclination angle on the acute angle side formed by the lateral main groove and the tire circumferential direction in the central land portion, the lower limit is set to 15 °. The upper limit is set to 85 °, and if this is exceeded, the drainage function as a groove in the horizontal main groove will decrease, and the horizontal main groove in the tire circumferential direction will decrease. This is because the grooves become close to each other and the low noise performance deteriorates.

  Also, the lower limit of the inclination angle on the acute angle side between the lateral main groove in the end region land portion and the tire circumferential direction is set to 65 °, because if it falls below this, there is a concern about deterioration of uneven wear resistance performance. Yes, the upper limit is 90 ° because if it exceeds this, the drainage function of the horizontal main groove will deteriorate.

  According to a fourteenth aspect of the present invention, in the pneumatic tire according to any one of the first to thirteenth aspects, when the tread is viewed in a plan view, the recessed portion has a planar shape of a substantially isosceles triangle. It is characterized by.

  In the pneumatic tire according to claim 14, in order to gradually reduce the area of the dent with wear, the shape of the dent is substantially an isosceles triangle when the tread is viewed in plan. .

  According to a fifteenth aspect of the present invention, in the pneumatic tire according to any one of the first to fourteenth aspects, the concave portion and one side of the concave portion that separates the lateral main groove adjacent to the concave portion. A sipe having a shape that is continuous and inclined with respect to the tire circumferential direction at an angle smaller than the inclination angle of the lateral main groove is formed in the central region land portion.

  In the pneumatic tire according to claim 15, since the sipe having an inclination angle smaller than that of the horizontal main groove is arranged at a position continuous with one side of the recessed portion in the central region land portion, the drainage performance in the central region land portion. Can be further improved.

  As described above, according to the pneumatic tire of the present invention, it has an excellent effect that various performances such as steering stability performance, drainage performance, uneven wear resistance performance, and low noise performance can be balanced at a high level. .

Hereinafter, embodiments of the present invention will be described with reference to the drawings.
(First embodiment)
The pneumatic tire 100 according to the first embodiment includes a circumferential main groove 102, a central region land portion 104, an end region land portion 106, and a horizontal main groove 108 in FIG.

  The circumferential main groove 102 is a tire circumferential groove formed at least one on each side of the tire equatorial plane CL in the tread 110 and is adjacent to both sides in the width direction of the central region land portion 104 in the circumferential direction of the end portion. The main groove 102B is composed of two central circumferential main grooves 102A formed in the central region land portion 104, and the pneumatic tire 100 is formed with, for example, a total of four circumferential main grooves 102. Yes.

  The central region land portion 104 is a land portion formed between the circumferential main grooves 102 farthest from the tire equator plane CL on both sides of the tire equator plane CL, and is divided by two central circumferential main grooves 102A. The second central region land portion divided by the first central region land portion 104A continuous in the tire circumferential direction, the central circumferential main groove 102A and the end circumferential main groove 102B closest to the central circumferential main groove. 104B.

  104 A of 1st center area | region land parts comprise the center rib which continues in a tire peripheral direction, for example.

  The end region land portion 106 is a land portion formed between an end portion circumferential main groove 102B, which is an example of a circumferential main groove furthest from the tire equatorial plane CL, and the ground contact end 110A of the tread 110.

  In the end region land portion 106, a horizontal main groove 108 is formed. However, as shown in FIG. 1, the horizontal main groove 108 is also within the tread 110 outside the ground contact end 110A in the tire width direction. It is formed continuously, the direction changes in the tire circumferential direction at the end of the tread 110, and ends in a zigzag shape. In the vicinity of the terminal portion, for example, a very short groove 112 is formed.

  Note that the shape of the horizontal main groove 108 and the like in the region beyond the grounding end 110A is not limited to the above.

  The lateral main groove 108 extends in a direction intersecting with the circumferential main groove 102 and is formed by arranging a plurality of rows in the tire circumferential direction, and is a first central region land portion that is an example of the central region land portion 104. Both ends of the horizontal main groove 108 in 104B are terminated without directly opening the central circumferential main groove 102A and the end circumferential main groove 102B adjacent to the both ends, and the recessed portion 114 is formed in the terminal portion 108A. Is formed.

  As shown in FIG. 1 and FIG. 2, the recess 114 has the lateral main portion in each region from the terminal end portion 108A to the central circumferential main groove 102A and the end central region land portion 102B adjacent to the terminal end portion 108A. The groove 108 is formed such that the width gradually decreases from the portion including the extension line of one groove wall 108B in the tire circumferential direction, and the depth gradually increases from the tread 110B of the tread 110.

  The recess 114 has a triangular planar shape when the tread 110 is viewed in plan. Specifically, the length of two sides excluding the side on the extension line of the groove wall 108B is approximately the same. It is formed in a substantially isosceles triangle that is long in the circumferential direction.

  As shown in FIG. 1, the inclination direction of the recess 114 is the same in both ends of the horizontal main groove 108 defined by the adjacent central circumferential main groove 102A and end circumferential main groove 102B. . In addition, when compared on both sides of the tire equatorial plane CL, the inclination directions of the recessed portions 114 are opposite to each other.

  One recess 114 in both end portions 108 </ b> A of the horizontal main groove 108 ends without opening in the central circumferential main groove 102 </ b> A adjacent to the recess 114.

  A narrow-width rib 116 is formed between the recess 114 and the central circumferential main groove 102A, that is, near the tire equator surface of the central region land portion 104, in the tire circumferential direction.

  The other recess 114 opens into the end circumferential main groove 102 </ b> B adjacent to the recess 114.

  The shape of the recess 114 and the depth of the horizontal main groove 108 are not limited to those shown in the drawing.

  The lateral main groove 108 in the end region land portion 106 terminates without opening in the end portion circumferential main groove 102B adjacent to the end region land portion 106, and the end portion 108C and the end portion circumferential direction Narrow end ribs 118 are formed between the main groove 102B and continuous in the tire circumferential direction.

  The width of the narrow end rib 118 is 10 to 95% of the width of the end region land portion 106 where the narrow end rib 118 is located.

  The lower limit of the width of the narrow end rib 118 is set to 10% of the width of the end region land portion 106 where the narrow end rib 118 is located. In other words, the length of the horizontal main groove 108 is extended, so that the effectiveness with respect to uneven wear resistance and low noise performance is reduced, and the upper limit is set to 95%. It is because it will lead to the deterioration of the drainage performance at the time of cornering.

  A sipe 120 is formed on the narrow end rib 118 extending from the terminal end 108C of the lateral main groove 108 in the end region land portion 106 to the extension line of one groove wall 108D of the lateral main groove 108.

  The sipe 120 is provided in order to improve the ride comfort of the vehicle by optimizing the land portion rigidity of the narrow end rib 118.

  The inclination angle on the acute angle side formed by the lateral main groove 108 and the tire circumferential direction in the central region land portion 104 is, for example, 15 to 80 °. This is because if the angle is less than 15 °, the angle is excessively increased and the rigidity of the land portion is lowered, and there is a concern that the steering stability performance may be deteriorated. If the angle exceeds 85 °, the drainage function as a groove in the horizontal main groove 108. This is because the horizontal main grooves 108 are close to each other in the tire circumferential direction and the low noise performance is deteriorated.

  The inclination angle on the acute angle side between the lateral main groove 108 and the tire circumferential direction in the end region land portion 106 is 65 to 90 °. This is because if the angle is less than 65 °, there is a concern that the uneven wear-resistant performance is deteriorated, and if it exceeds 90 °, the drainage function of the horizontal main groove 108 is deteriorated.

  As shown in FIG. 1, the second central region land portion 104 </ b> B is continuous with the one side 114 </ b> A of the recess 114 that separates the recess 114 from the adjacent horizontal main groove 108, and the horizontal main groove 108. A sipe 122 having a shape inclined with respect to the tire circumferential direction at an angle smaller than the inclination angle is formed.

  Since the sipe 122 is continuously formed on one side 114A of each recessed portion 114 at both end portions 108A of the horizontal main groove 108, the sipe 122 progresses in the tire circumferential direction which is opposite to the inclination direction of the recessed portion 114. It is configured as a continuous sipe that approaches each other and meets at a vertex 124.

  That is, the sipe 122 extends from the apex 124 in the direction of the central circumferential main groove 102A and the end circumferential main groove 102B, and on the central circumferential main groove 102A side, the end portion 108A of the lateral main groove 108 is halfway. The tire 114 further extends in the tire circumferential direction while forming one side 114A of the recess 114, and ends with the formation of one side 114B of the recess 114 located adjacent to the tire circumferential direction.

  On the other hand, on the end circumferential main groove 102 </ b> B side, the sipe 122 terminates when reaching the one side 114 </ b> A of the recess 114, and the one side 114 </ b> A has a continuous shape on the extension of the sipe 122. The one side 114A also coincides with the contour of the side surface on the end circumferential main groove 102B side in the second central region land portion 104B, and the contour is a recess 114 located adjacent to the tire circumferential direction in which the contour extends. It extends to the point where one side 114B is formed and terminates.

The tread pattern is point-symmetric about the tire equatorial plane CL.
(Second Embodiment)
In the pneumatic tire 200 according to the second embodiment, as shown in FIG. 3, the recess 114 is formed in both the central circumferential main groove 102 </ b> A and the end circumferential main groove 102 </ b> B adjacent to the recess 114. Each has an opening.

  Therefore, the sipe 122 on the side of the central circumferential main groove 102A terminates at the side 114A of the recessed portion 114 as in the end circumferential direction main groove 102B side, and the one side 114A extends from the sipe 122. It has a continuous shape on top. The one side 114A coincides with the contour of the side surface on the central circumferential main groove 102A side in the second central region land portion 104B, and the contour of the recess 114 located adjacent to the tire circumferential direction in which the contour extends. It extends to the point where the side 114B is formed and terminates.

Since other parts are the same as those of the first embodiment, the same parts are denoted by the same reference numerals in the drawings, and description thereof is omitted.
(Third embodiment)
In the pneumatic tire 300 according to the third embodiment, as shown in FIG. 4, the inclining direction of the recess 114 is laterally defined by the adjacent central circumferential main groove 102A and end circumferential main groove 102B. The opposite ends of the main groove 108 are opposite to each other.

  For this reason, the sipe 322 is formed in a substantially S shape over two adjacent horizontal main grooves 108, and specifically, on one side 114A of the recess 114 located on the end circumferential direction main groove 102B side. The tire continuously extends in the tire circumferential direction opposite to the inclination direction of the recess 114 and toward the central circumferential main groove 102A, and is bent in the middle. It ends so as to continue to one side 114A of the recess 114 on the direction main groove 102A side.

  The rotation direction of the pneumatic tire 300 is designated in the direction of arrow R. When the pneumatic tire 300 rotates in the arrow R direction on the wet road surface, water (not shown) in the central circumferential main groove 102A and the end circumferential main groove 102B flows in the arrow F direction.

  At this time, the water sandwiched between the tread 110B and the road surface passes through the horizontal main groove 108 or the sipe 322, and further reaches the recess 114 adjacent to the end circumferential main groove 102B, and from the recess 114 to the end circumferential main. It flows into the groove 102B.

  Further, a part of the water flowing in the central circumferential main groove 102A also enters the horizontal main groove 108 or the sipe 322 from the concave portion 114 adjacent to the central circumferential main groove 102A, and ends from the concave portion 114 on the opposite side. It flows in the circumferential main groove 102B.

  Since the tread pattern is line symmetric about the tire equatorial plane CL, the drainage performance of the pneumatic tire 300 is further enhanced than in the first embodiment and the second embodiment.

Since other parts are the same as those of the second embodiment, the same parts are denoted by the same reference numerals and description thereof will be omitted.
(Test example)
Table 2 shows the results of tests on the hydroplaning performance when wet, the steering stability performance when dry, the steering stability performance when wet, the pattern noise, the ride comfort, and the uneven wear resistance performance of each pneumatic tire shown in Table 1. Shown in

  The pneumatic tire 400 according to the conventional example has a tread pattern as shown in FIG. 5, 402 is a circumferential main groove, 402A is a central circumferential main groove, 402B is an end circumferential main groove, 404 is a central region land portion, 404A is a first central region land portion, and 404B is a second central region. Land portion, 406 is an end region land portion, 408 is a horizontal main groove, 410 is a tread, 410A is a ground end, 418 is a narrow end rib, and 420, 422, and 424 are sipes, respectively.

  Each evaluation value is indicated by an index with the conventional example being 100, and a larger value indicates a better result.

  The tire size is 205 / 55R16, the groove depth is 8.3 mm, the air pressure is 230 kPa, and the load is equivalent to a vehicle + two passengers.

  The hydroplaning performance when wet was evaluated based on the maximum speed that the test driver felt that the hydroplaning phenomenon did not occur when a wet road surface with a water depth of 5 mm was passed.

  Steering stability when dry was evaluated by the feeling of a test driver when driving on a circuit course with a dry road surface in various driving modes.

  Steering performance when wet was evaluated by the feeling of a test driver when driving on a circuit course with wet roads in various driving modes.

  Pattern noise and ride comfort were evaluated based on the feeling of the test driver when driving on a dry general road in various driving modes.

  The uneven wear resistance performance was evaluated based on the amount of step wear between adjacent land portions when traveling 5000 km when traveling on a general road in a dry state in various traveling modes.

  According to this test example, it can be seen that in any of Examples 1 to 3, each performance is improved with a better balance than the conventional example.

In the pneumatic tire concerning a 1st embodiment of the present invention, it is a figure expanding and showing a tread pattern on a plane. (A) is 2a-2a arrow sectional drawing in FIG. 1, (b) is 2b-2b arrow sectional drawing in FIG.1, FIG3 and FIG.4. In the pneumatic tire concerning a 2nd embodiment of the present invention, it is a figure expanding and showing a tread pattern on a plane. In the pneumatic tire concerning a 3rd embodiment of the present invention, it is a figure expanding and showing a tread pattern on a plane. In the pneumatic tire which concerns on a prior art example, it is a figure which expand | deploys and shows a tread pattern in a plane.

Explanation of symbols

DESCRIPTION OF SYMBOLS 100 Pneumatic tire 102 Circumferential main groove 102A Central circumferential main groove 102B End circumferential main groove 104 Central area land part 104A First central area land part 104B Second central area land part 106 End area land part 108 Horizontal main Groove 108A end portion 108B groove wall 108C end portion 108D groove wall 110 tread 110A grounding end 110B tread surface 114 recess 114A one side 116 narrow rib 118 narrow end rib 120 sipe 122 sipe 200 pneumatic tire 300 pneumatic tire 322 sipe

Claims (15)

At least one circumferential main groove formed on each side of the tire equator in the tread, and a central region land formed between the circumferential main grooves furthest from the tire equator on both sides of the tire equator And an end region land portion formed between the circumferential main groove furthest from the tire equatorial plane and the grounded end of the tread, and the tire circumferential direction while extending in a direction intersecting the circumferential main groove A pneumatic tire having a horizontal main groove formed by arranging a plurality of
At least one end of the horizontal main groove in the central region land portion terminates without opening directly to the circumferential main groove adjacent to the one end,
In the region from the end portion of the horizontal main groove to the circumferential main groove adjacent to the end portion, the width gradually decreases from the portion including the extension line of one groove wall in the horizontal main groove toward the tire circumferential direction. And having a recess formed so that the depth gradually increases from the tread surface of the tread,
Pneumatic tire characterized by.   2. The pneumatic tire according to claim 1, wherein the inclining directions of the recesses are opposite to each other at both ends of the horizontal main groove defined by the adjacent circumferential main grooves.   2. The pneumatic tire according to claim 1, wherein the inclining direction of the recess is the same in both ends of the horizontal main groove defined by the adjacent circumferential main grooves. Both ends of the horizontal main groove in the central region land portion are terminated without opening directly to the circumferential main groove adjacent to the both ends,
The recesses are formed at both end portions of the transverse main groove;
The pneumatic tire according to any one of claims 1 to 3, wherein:   The pneumatic tire according to any one of claims 1 to 4, wherein the recessed portion opens in the circumferential main groove adjacent to the recessed portion. The dent is terminated without opening in the circumferential main groove adjacent to the dent,
The pneumatic tire according to any one of claims 1 to 4, wherein a narrow-width rib continuous in the tire circumferential direction is formed between the recess and the circumferential main groove. One of the recesses at both end portions of the horizontal main groove terminates without opening in the circumferential main groove adjacent to the recess,
A narrow-width rib that is continuous in the tire circumferential direction is formed between the recess and the circumferential main groove,
The other recess is open in the circumferential main groove adjacent to the recess,
The pneumatic tire according to claim 4.   The pneumatic tire according to claim 6 or 7, wherein the narrow rib is formed near the tire equatorial plane of the central region land portion. The horizontal main groove in at least one of the end region land portions terminates without opening in the circumferential main groove adjacent to the end region land portion,
A narrow end rib continuous in the tire circumferential direction is formed between the terminal portion and the circumferential main groove;
The pneumatic tire according to any one of claims 1 to 8, wherein:   The pneumatic tire according to claim 9, wherein the width of the narrow end rib is 10 to 95% of the width of the end region land portion where the narrow end rib is located.   The sipe is formed on the narrow end rib on the extension line of one groove wall of the horizontal main groove from the terminal end of the horizontal main groove in the end region land portion. The pneumatic tire according to claim 10. The circumferential main groove is composed of end circumferential main grooves adjacent to both sides in the width direction of the central region land portion, and two central circumferential main grooves formed in the central region land portion,
The central region land portion is divided by the two central circumferential main grooves and is continuous with the first central region land portion in the tire circumferential direction, the central circumferential main groove and the central circumferential main groove closest to the central circumferential land groove. It is composed of a second central region land section partitioned by an end circumferential main groove,
The recess is formed at the terminal end of the transverse main groove in the second central region land portion;
The pneumatic tire according to any one of claims 1 to 11, wherein: The inclination angle on the acute angle side formed by the lateral main groove and the tire circumferential direction in the central region land portion is 15 to 80 °,
The acute angle of the side main groove in the end region land portion and the tire circumferential direction is 65 to 90 °.
The pneumatic tire according to any one of claims 1 to 12, wherein:   The pneumatic tire according to any one of claims 1 to 13, wherein, when the tread is viewed in plan, the recessed portion has a planar shape of a substantially isosceles triangle. A sipe having a shape that is continuous with one side of the concave portion that separates the concave main portion from the adjacent horizontal main groove and is inclined with respect to the tire circumferential direction at an angle smaller than the inclination angle of the horizontal main groove. Being formed in the central region land,
The pneumatic tire according to any one of claims 1 to 14, wherein:

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