JP2016141157A - Pneumatic tire - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a pneumatic tire that can secure wet brake performance, reduce rolling resistance and suppress uneven abrasion.SOLUTION: In an outside second land part 24 are formed first inclined grooves 32 that partition block-like land parts 34, and in the block-like land parts 34 are formed second inclined grooves 42 that extend from one side toward the other side in a tire width direction and terminate in the land part. Groove widths of the first inclined grooves 32 gradually increase from one side toward the other side in the tire width direction, and groove widths of the second inclined grooves 42 gradually decrease from one side toward the other side in the tire width direction. In a center land part 26 on a tire equator face CL are formed third inclined grooves 46 which extend and whose groove widths gradually decrease, from one side toward the other side in the tire width direction, and which terminate in the center land part 26.SELECTED DRAWING: Figure 1

Description

  The present invention relates to a pneumatic tire having a tread with land portions defined by a plurality of circumferential grooves.

  There has been proposed a pneumatic tire provided with a tread having land portions partitioned by a plurality of circumferential grooves (see Patent Document 1).

Japanese Patent No. 5342122

  In this type of pneumatic tire, the rigidity of the land portion is ensured, but it is further required to ensure wet brake performance, reduce rolling resistance, and suppress uneven wear.

  In view of the above facts, the present invention aims to provide a pneumatic tire capable of ensuring the rigidity of the land portion, ensuring wet brake performance, reducing rolling resistance, and suppressing uneven wear. To do.

  The pneumatic tire according to claim 1 is provided with a plurality of land portions provided on a tread and partitioned by a plurality of circumferential grooves extending along a tire circumferential direction, and a first land portion of the plurality of land portions. In the tire width direction and at a plurality of intervals in the tire circumferential direction, the groove width gradually increases from one side to the other side in the tire width direction, and the block land portion is partitioned. 1 inclined groove and the block-shaped land portion, which is disposed on the one side of the block-shaped land portion, extends from one side of the tire width direction toward the other side and inclines with respect to the tire width direction, and the tire width The groove width gradually decreases from one side of the direction toward the other side, the second inclined groove whose end on the other side in the tire width direction terminates in the block-shaped land portion, the tire equatorial plane, and the first Placed on one side of the tire in the width direction A second land portion having a narrower width than the first land portion, and the second land portion is disposed on the one side of the second land portion, and from one side in the tire width direction to the other side. Extending toward the tire width direction, the groove width gradually decreases from one side in the tire width direction to the other side, and the end on the other side in the tire width direction terminates in the second land portion. A third inclined groove.

  Since the pneumatic tire according to claim 1 forms a plurality of circumferential grooves extending in the tire circumferential direction in the tread to partition the land portion, the road between the tread and the road surface during wet road running Water can be taken into the circumferential groove and drained. Thereby, wet brake performance can be obtained.

  Since a plurality of first inclined grooves are formed in the first land portion, when traveling on a wet road surface, water between the first land portion and the road surface is taken into the first inclined groove to form a circumferential groove. It can be drained. Since the groove width of the first inclined groove gradually increases from one side to the other side in the tire width direction, drainage can be improved and wet brake performance can be improved as compared with a case where the groove width is constant. .

  In the first land portion, the groove width of the first inclined groove gradually increases from one side in the tire width direction toward the other side, and the second inclined groove gradually decreases from one side in the tire width direction toward the other side. Therefore, the difference in rigidity between the rigidity on the one side in the tire width direction and the rigidity on the other side in the tire width direction of the block-shaped land portion between the first inclined groove and the first inclined groove is eliminated, and the tire width direction It is possible to balance the rigidity on one side and the rigidity on the other side in the tire width direction. Thereby, the twist of a block-like land part at the time of a block-like land part grounding can be suppressed, and the partial wear of a block-like land part can be suppressed.

  In addition, since the first land portion is divided into a plurality of tire circumferential directions by the plurality of first inclined grooves, dragging on the road surface during traveling is suppressed and rolling resistance is reduced as compared with a case where the first land portion is not divided. be able to.

  The groove width gradually decreases from one side in the tire width direction to the other side at the end portion on the one side in the tire width direction of the second land portion, and the end portion on the other side in the tire width direction is in the second land portion. Since the third inclined groove that terminates at is formed, water between the second land portion and the road surface can be taken into the third inclined groove and drained into the circumferential groove during wet road running.

  Since the 3rd inclined groove does not cross the 2nd land part, the rigidity of the 2nd land part cannot fall easily. Since the second land portion is narrower than the first land portion and has a lower rigidity than the first land portion, the third land portion terminates in the land portion instead of forming a groove traversing in the tire width direction. By forming the inclined groove, the wet brake performance can be improved while securing the rigidity of the second land portion.

  When the vehicle is traveling straight, the contact pressure near the center of the tread in the tire width direction, that is, near the tire equatorial plane tends to be higher than that on the shoulder side, and the rigidity of the tread near the tire equatorial plane is regarded as important. In the pneumatic tire according to claim 1, since the second land portion is arranged on the tire equator plane, the tread tire equator vicinity is compared with the case where the second land portion is not arranged on the tire equator plane. Can be ensured, and stability during straight running can be improved.

  When the vehicle corners, the load received from the road surface by the pneumatic tire disposed on the outer side in the cornering radial direction increases, and the contact pressure on the outer side in the vehicle width direction increases in the tread of the pneumatic tire. For this reason, in the pneumatic tire according to claim 1, the first land portion having a relatively high rigidity is located on the outer side in the vehicle width direction than the second land portion having a narrow width and a relatively low rigidity. By mounting on the vehicle, deformation of the second land portion can be suppressed.

  Further, in the second land portion of the pneumatic tire mounted as described above, the load on the outer side in the vehicle width direction is relatively larger than the inner side in the vehicle width direction during cornering. Since the groove width of the third inclined groove formed in the second land portion gradually decreases from the inner side in the vehicle width direction toward the outer side in the vehicle width direction, the second land portion is smaller than the inner side in the vehicle width direction. Since the rigidity on the outer side in the vehicle width direction increases, that is, the rigidity on the side where the load increases during cornering, the deformation during cornering can be suppressed, and cornering performance can be ensured.

  According to a second aspect of the present invention, in the pneumatic tire according to the first aspect, the second land portion includes the second land portion between the third inclined groove and the third inclined groove. A first sipe that crosses the section is formed.

  In the pneumatic tire according to claim 2, a first sipe that crosses the second land portion is formed between the third inclined groove and the third inclined groove of the second land portion. Are divided into a plurality of portions in the tire circumferential direction. Thereby, during traveling, dragging of the second land portion with respect to the road surface is suppressed, the grounding property of the second land portion is improved, rolling resistance is reduced, and uneven wear of the second land portion is suppressed. .

  Invention of Claim 3 is a pneumatic tire of Claim 2, The 3rd land part arrange | positioned on the one side of the tire width direction of a said 2nd land part, The 3rd land part And a notch disposed on the extension line of the first sipe.

  In the pneumatic tire according to claim 3, when running on a wet road surface, water between the third land portion and the road surface can be taken into the notch and drained into the circumferential groove. Since the notch does not cross the third land portion, the rigidity of the third land portion is unlikely to decrease. Therefore, by forming a notch instead of forming a groove traversing in the tire width direction, the wet brake performance can be improved while ensuring the rigidity of the third land portion.

  When running on a wet road surface, when the second land portion comes in contact with the ground, the second land portion is compressed and the groove wall of the first sipe bulges, the groove width becomes narrow and the volume of the first sipe decreases. The water in the first sipe is ejected from the end of the first sipe toward the circumferential groove. When running on a wet road surface, water taken into the circumferential groove flows in the circumferential groove in the circumferential direction of the tire, but the water in the first sipe circulates against the water flowing in the circumferential groove. When ejected from the side of the directional groove, the water flow in the circumferential groove is disturbed.

  When water of the first sipe is ejected toward a portion where the circumferential groove notch is not formed (that is, when water is ejected into a narrow space) and toward a portion where the circumferential groove notch is formed Compared with the case where the water of the first sipe is ejected (that is, when the water is ejected in a wide space), the water is more turbulent if the water is ejected in a wide portion where the notch of the circumferential groove is formed. Is small, and disturbs the water flow along the circumferential groove.

  In the pneumatic tire according to claim 3, the circumferential groove and the cutout are integrated by forming the cutout of the third land portion on the extension line of the first sipe of the second land portion. The volume of the part becomes larger than the volume of the part having only the circumferential groove. For this reason, it becomes difficult to disturb the water flow along the circumferential groove when water is ejected from the end of the first sipe toward the circumferential groove.

  According to a fourth aspect of the present invention, in the pneumatic tire according to the third aspect, the second sipe is formed on the third land portion on an extension line of the third inclined groove of the second land portion. Has been.

  In the pneumatic tire according to claim 4, the second sipe is formed on the third land portion on the extension line of the third inclined groove of the second land portion. For this reason, when the water taken in the third inclined groove of the second land portion is discharged from the end portion of the third inclined groove during the wet road surface running, the discharged water is stored in the third inclined groove. It drains to the tire width direction outside of the 3rd land part via the 2nd sipe arranged on the extension line. Therefore, by disposing the third land portion on the outermost side in the tire width direction of the tread, the water taken into the third inclined groove of the second land portion is allowed to pass through the outer end in the tire width direction of the third land portion, In other words, the water can be drained in the shortest distance in the direction of the tread end. Thereby, the wet brake performance can be improved.

  Further, in the pneumatic tire according to claim 4, since the third land portion is divided in the tire circumferential direction by the second sipe, dragging of the third land portion with respect to the road surface is suppressed during traveling, The grounding property of the land portion 3 is improved, rolling resistance is reduced, and uneven wear of the third land portion is suppressed.

  Furthermore, in the pneumatic tire according to claim 4, since the second sipe is arranged on the extension line of the third inclined groove, the third inclined groove and the second sipe are not aligned in the tire width direction. Since the inclined groove and the second sipe do not touch the road surface at the same time, noise during traveling can be suppressed.

  According to a fifth aspect of the present invention, in the pneumatic tire according to the third or fourth aspect, the third land portion includes a longitudinal direction of the third land portion on the opposite side of the notch. A third sipe extending in the intersecting direction and spaced from the notch is formed.

  By forming the third sipe in the third land portion, water can be taken in between the third land portion and the road surface and drained to the circumferential groove, and the wet brake performance can be improved. .

  Since the third sipe extending in the direction intersecting the longitudinal direction of the third land portion is formed in the third land portion, the third land portion divided by the second sipe in the tire circumferential direction further extends in the tire circumferential direction. It is divided and rolling resistance can further be reduced. Moreover, since the 3rd sipe and the notch are spaced apart, the rigidity of the 3rd land part can be improved compared with the case where the 3rd sipe and the notch are connected.

  As described above, the pneumatic tire of the present invention has excellent effects of ensuring wet brake performance, reducing rolling resistance, and suppressing uneven wear.

1 is a plan view showing a tread of a pneumatic tire according to a first embodiment of the present invention. It is sectional drawing (2-2 sectional view taken on the line of FIG. 1) which shows a 1st inclination groove | channel. It is sectional drawing (3-3 line sectional drawing of FIG. 1) which shows a 2nd inclination groove | channel. FIG. 4 is a sectional view showing a third inclined groove (a sectional view taken along line 4-4 in FIG. 1). It is sectional drawing (5-5 sectional view taken on the line of FIG. 1) which shows a 1st sipe. (A) is a top view which shows a notch, (B) is 6B-6B sectional drawing of FIG. 6 (A) which shows a notch, (C) is 6C-6C of FIG. 6 (A) which shows a notch. It is line sectional drawing. It is sectional drawing which shows the 2nd sipe (7-7 sectional view taken on the line of FIG. 1). It is sectional drawing (8-8 sectional view taken on the line of FIG. 1) which shows a 3rd sipe. It is sectional drawing (9-9 line sectional drawing of FIG. 1) which shows a 4th sipe. It is a step figure (10-10 line sectional view of Drawing 1) showing a lug groove. It is a top view which shows the tread of the pneumatic tire which concerns on the 2nd Embodiment of this invention. (A) is a top view which shows a hole, (B) is 12B-12B sectional drawing of the hole shown to FIG. 12 (A), (C) is 12C-12C of the hole shown to FIG. 12 (A). It is line sectional drawing.

[First Embodiment]
The pneumatic tire 10 according to the first embodiment of the present invention will be described with reference to FIGS. As shown in FIG. 1, the tread 12 of the pneumatic tire 10 of the present embodiment has an out-side shoulder circumferential groove 14, an out-side center circumferential groove 16, from the arrow OUT direction side to the arrow IN direction side, An in-side center circumferential groove 18 and an in-side shoulder circumferential groove 20 are formed.

  The pneumatic tire 10 of the present embodiment is designated with the vehicle inner and outer vehicle mounting directions when the vehicle is mounted, and a mark (not shown) for specifying the mounting direction is given to the side surface. Yes. In the drawings, an arrow OUT direction indicates a direction outside the vehicle width direction when the pneumatic tire 10 is mounted on the vehicle, and an arrow IN direction indicates a direction inside the vehicle width direction when the pneumatic tire 10 is mounted on the vehicle. Indicates. Note that the arrow IN direction side of the present embodiment corresponds to one side of the present invention, and the arrow OUT direction side of the present embodiment corresponds to the other side of the present invention.

  The tread 12 has an out-side shoulder land portion 22, an out-side shoulder land portion 22, an out-side center circumferential groove 16, an in-side center circumferential groove 18, and an in-side shoulder circumferential groove 20. The side second land portion 24, the center land portion 26, the in-side second land portion 28, and the in-side shoulder land portion 30 are partitioned. In the present embodiment, the out-side second land portion 24 corresponds to the first land portion of the present invention, the center land portion 26 corresponds to the second land portion of the present invention, and the in-side second land portion 28 corresponds to the present invention. It corresponds to the third land part. In the present embodiment, the center land portion 26 and the in-side second land portion 28 are formed to be narrower than the out-side second land portion 24.

(Outside second land)
First, in the out side second land portion 24, a plurality of first inclined grooves 32 that are inclined upward to the left in the drawing and cross the out side second land portion 24 are formed at intervals in the tire circumferential direction. The first inclined groove 32 has an end on the arrow IN direction side connected to the out-side center circumferential groove 16 and an end on the arrow OUT direction side connected to the out-side shoulder circumferential groove 14. The first inclined groove 32 has a groove width and a groove depth that gradually increase from the arrow IN direction side to the arrow OUT direction side. For this reason, the first inclined groove 32 makes it easy for water taken into the groove to flow from the arrow IN direction side to the arrow OUT direction side.

  The out-side block land portion 34 defined by the out-side shoulder circumferential groove 14, the out-side center circumferential groove 16, and the first inclined groove 32 has a substantially parallelogram shape in a tread plan view. A corner 34A on the arrow A direction side formed by the direction groove 16 and the first inclined groove 32, and a corner 34B on the arrow B direction side formed by the out-side shoulder circumferential groove 14 and the first inclined groove 32. Are both at an acute angle.

  Further, the out-side block land portion 34 includes a corner portion 34C on the arrow B direction side formed by the out-side center circumferential groove 16 and the first inclined groove 32, and the out-side shoulder circumferential groove 14 and the first inclined surface. Both corners 34D on the arrow A direction side formed by the grooves 32 are obtuse. The first inclined groove 32 has an arc shape that is convex toward the arrow B direction in a tread plan view, and the angle of the corner portion 34A when the tread 12 is viewed in plan is smaller than the angle of the corner portion 34B. Of the four corners of the out-side block land portion 34, the acute angle is the smallest. In addition, the first inclined groove 32, the third inclined groove 46, the notch 54, the first sipe 50, and the second inclined groove 42 are connected in a substantially elliptical shape in a tread plan view.

  As shown in FIG. 2, the first inclined groove 32 has a substantially V-shaped cross section, the wall surface 32A on the arrow A direction side is perpendicular to the tread 12A, and the wall surface 32B on the arrow B direction side is Inclined with respect to the normal HL standing on the tread 12A. Note that when the angle of the wall surface 32B with respect to the normal line HL standing on the tread 12A is θ1, the angle θ1 of the wall surface 32B gradually increases from the arrow IN direction side to the arrow OUT direction side. A chamfer 38 is formed at the corner formed by the wall surface 32A and the tread 12A. A sipe 40 is formed at the groove bottom of the first inclined groove 32.

  As shown in FIG. 1, among the four corners of the out-side block land portion 34, the one having the lowest rigidity is an acute corner portion 34A having the smallest angle. Therefore, in the pneumatic tire 10 of the present embodiment, the wall surface 32B on the arrow B direction side of the first inclined groove 32 forming the corner portion 34A is inclined (see FIG. 2), and is set on the tread 12A. The rigidity of the corner portion 34A is increased as compared with the case where it is not inclined with respect to the normal line HL (that is, perpendicular to the tread 12A).

  In addition, a second inclined groove 42 is formed between the first inclined groove 32 and the first inclined groove 32 at the end on the arrow IN direction side of the out-side second land portion 24. The second inclined groove 42 extends in the direction of the arrow OUT from the end of the out side second land portion 24 on the arrow IN direction side, and terminates near the center in the width direction of the out side second land portion 24. Similar to the first inclined groove 32, the second inclined groove 42 is inclined upward in the drawing, and the groove width gradually decreases from the arrow IN direction side to the arrow OUT direction side. As shown in FIG. 3, the cross-sectional shape of the second inclined groove 42 is V-shaped. A chamfer 44 is formed at a corner formed by the groove wall 42A of the second inclined groove 42 and the tread 12A.

  As shown in FIG. 1, in the out-side second land portion 24, the groove width of the first inclined groove 32 gradually increases from the arrow IN direction side to the arrow OUT direction, and the groove width of the second inclined groove 42 is an arrow mark. Since it gradually decreases from the IN direction toward the arrow OUT direction, the rigidity on the arrow IN direction side of the out-side block land portion 34 between the first inclined groove 32 and the first inclined groove 32 and the arrow OUT direction side The rigidity difference between the rigidity of the arrow IN direction and the rigidity of the arrow OUT direction can be balanced. Thereby, the twist of a block-like land part at the time of a block-like land part grounding can be suppressed, and uneven wear can be suppressed.

(Center Rikubu)
A plurality of third inclined grooves 46 are formed at intervals in the tire circumferential direction at the end of the center land portion 26 on the arrow IN direction side. The third inclined groove 46 extends from the end of the center land portion 26 on the arrow IN direction side in the arrow OUT direction, and terminates slightly on the arrow OUT direction side from the vicinity of the center in the width direction of the center land portion 26. The third inclined groove 46 is inclined upward in the drawing, and the groove width gradually decreases from the arrow IN direction side to the arrow OUT direction side.

  As shown in FIG. 4, the third inclined groove 46 has a substantially V-shaped cross section, the wall surface 46A on the arrow A direction side is perpendicular to the tread 12A, and the wall surface 46B on the arrow B direction side is Inclined with respect to the normal HL standing on the tread 12A. Further, a chamfer 48 is formed at a corner portion formed by the wall surface 46A of the third inclined groove 46 and the tread surface 12A.

  As shown in FIG. 1, the center land portion 26 includes an out-side center circumferential groove 16 across the center land portion 26 in the width direction between the third inclined groove 46 and the third inclined groove 46. A first sipe 50 opening in the in-side center circumferential groove 18 is formed. The first sipe 50 is inclined upward in the drawing. As shown in FIG. 5, a chamfer 52 is formed at a corner formed by the groove wall 50A of the first sipe 50 and the tread 12A.

(Inland second land)
As shown in FIG. 1, a notch 54 is formed on the end of the in-side second land portion 28 on the arrow OUT direction side on the extension line of the first sipe 50 of the center land portion 26. As shown in FIG. 6A, the notch 54 has a substantially semi-elliptical shape in plan view, and the major axis of the ellipse is inclined upward in the drawing. As shown in FIG. 6B, the depth of the notch 54 gradually increases toward the arrow C direction side (that is, the in-side center circumferential groove 18 side) along the long axis of the ellipse. As shown in FIG. 6C, the cutout 54 has a substantially semicircular cross-sectional shape along the minor axis of the ellipse. The notch 54 is a recess or a recess formed from the circumferential groove side toward the land portion in the tread plan view.

  As shown in FIG. 1, a second sipe 56 is formed on the in-side second land portion 28 on the extension line of the third inclined groove 46 of the center land portion 26. The second sipe 56 is inclined leftward in the drawing, crosses the in-side second land portion 28 in the width direction, and opens to the in-side center circumferential groove 18 and the in-side shoulder circumferential groove 20. As shown in FIG. 7, a chamfer 58 is formed at a corner formed by the groove wall 56A of the second sipe 56 and the tread 12A.

  As shown in FIG. 1, a third sipe 60 is formed on the opposite side of the notch 54 at the end of the in-side second land portion 28 on the arrow IN direction side. The third sipe 60 extends from the end of the in-side second land portion 28 on the arrow IN direction side in the direction of the arrow OUT, terminates near the center in the width direction of the in-side second land portion 28, and is separated from the notch 54. ing. Similar to the second sipe 56, the third sipe 60 is inclined upward in the drawing. Further, as shown in FIG. 8, a chamfer 62 is formed at a corner formed by the groove wall 60A of the third sipe 60 and the tread surface 12A.

(Inside shoulder land)
As shown in FIG. 1, the in-side shoulder land portion 30 is formed with fourth sipes 63 </ b> A to 63 </ b> C in the tire circumferential direction that incline leftward and cross the in-side shoulder land portion 30. The fourth sipe 63A is formed on the extension line of the second sipe 56, the fourth sipe 63B is formed on the extension line of the third sipe 60, and the fourth sipe 63C is formed between the fourth sipe 63A and the fourth sipe 63B.

(Outside shoulder land)
A cutout 64 is formed on the extended line of the first inclined groove 32 at the end of the out-side shoulder land portion 22 on the arrow IN direction side. The notch 64 has a substantially triangular shape in plan view. The notch 64 is gradually increased in depth toward the arrow IN direction. Further, the end on the arrow IN direction side of the out-side shoulder land portion 22 extends between the notch 64 and the notch 64 from the end on the arrow IN direction side of the out-side shoulder land portion 22 to the arrow OUT direction side. A fifth sipe 66 is formed.

  A plurality of lug grooves 68 extending in the arrow IN direction from the ground contact end 12E of the tread 12 are formed in the end portion on the arrow OUT direction side of the out-side shoulder land portion 22 along the tire circumferential direction. Half of the plurality of lug grooves 68 are formed on the opposite side of the notch 64, and the end on the arrow IN direction side terminates near the center in the width direction of the out-side shoulder land portion 22. The remaining half of the plurality of lug grooves 68 are connected to the fifth sipe 66 near the center in the width direction of the out-side shoulder land portion 22.

  As shown in FIG. 9, chamfers 70 are formed at the corners formed by the groove wall 66A of the fifth sipe 66 and the tread surface 12A. As shown in FIG. 10, the groove wall 68A and the tread surface 12A of the lug groove 68 are formed. A chamfer 72 is formed at a corner formed by

(Function, effect)
Next, the operation and effect of the pneumatic tire 10 of the present embodiment will be described.
Since the outer shoulder circumferential groove 14, the outer center circumferential groove 16, the inner center circumferential groove 18, and the inner shoulder circumferential groove 20 extending along the tire circumferential direction are formed in the tread 12. The pneumatic tire 10 has obtained basic wet performance.

  As described above, since the first inclined groove 32 and the second inclined groove 42 are arranged in the out side second land portion 24 of the tread 12, water between the out side second land portion 24 and the road surface during running on a wet road surface. Can be taken into the first inclined groove 32 and the second inclined groove 42, and the water taken into the first inclined groove 32 can be discharged into the out-side shoulder circumferential groove 14, and the water taken into the second inclined groove 42 can be discharged. It can be discharged into the out-side center circumferential groove.

  Here, since the groove width of the first inclined groove 32 is gradually increased from the arrow IN direction side to the arrow OUT direction side, the drainage performance is improved compared to the case where the groove width is constant, and the arrow OUT direction side. The water can be efficiently flowed toward. Thus, since the 1st inclination groove | channel 32 and the 2nd inclination groove | channel 42 are formed in the out side 2nd land part 24, wet brake performance can be improved.

  In the center land portion 26, the third inclined groove 46 and the first sipe 50 take in water between the center land portion 26 and the road surface when traveling on a wet road surface, and the taken-in water in the in-side center circumferential groove 18. , And the out-side center circumferential groove 16 can be discharged. Thereby, wet brake performance can be improved.

  In the in-side second land portion 28, the notch 54, the second sipe 56, and the third sipe 60 take in water between the in-side second land portion 28 and the road surface when traveling on a wet road, It can be discharged into the side center circumferential groove 18 and the in-side shoulder circumferential groove 20. Thereby, wet brake performance can be improved.

  In the in-side shoulder land portion 30, the fourth sipes 63A to 63C take in water between the in-side shoulder land portion 30 and the road surface when running on a wet road surface, and discharge the taken-in water from the ground contact end 12E to the outside of the tire. can do. Thereby, wet brake performance can be improved.

  Further, in the out-side shoulder land portion 22, the notch 64, the fifth sipe 66, and the lug groove 68 take in water between the out-side shoulder land portion 22 and the road surface and take in the notch 64 when traveling on a wet road surface. The drained water can be discharged to the out-side shoulder circumferential groove 14, and the water taken into the fifth sipe 66 and the lug groove 68 can be drained from the ground contact end 12E to the outside of the tire. Thereby, wet brake performance can be improved.

  When running on a wet road surface, when the center land portion 26 comes in contact with the ground, the center land portion 26 is compressed, the groove wall 50A of the first sipe 50 is expanded, the groove width is reduced, and the volume of the first sipe 50 is reduced. . For this reason, the water taken into the first sipe 50 of the center land portion 26 is ejected from the end portion of the first sipe 50 toward the in-side center circumferential groove 18 and the out-side center circumferential groove 16. When running on a wet road surface, water flows in the in-side center circumferential groove 18 and the out-side center circumferential groove 16 in the circumferential direction, so the inside of the in-side center circumferential groove 18 and the out-side center circumferential groove 16 When water is ejected from the first sipe 50, the water flow in the in-side center circumferential groove 18 and the water flow in the out-side center circumferential groove 16 are disturbed.

  In the pneumatic tire 10 of the present embodiment, the notch 54 of the in-side second land portion 28 is disposed on the extended line on the arrow IN direction side of the first sipe 50, and the in-side center circumferential groove 18, the notch 54, The volume of the space where the two are integrated is larger than the volume of only the in-side center circumferential groove 18 in which the notch 54 is not formed.

  When water of the first sipe 50 is ejected to a portion that is not integral with the notch 54 of the in-side center circumferential groove 18, that is, when water is ejected into a narrow space, the notch 54 and the in-center center circumference When the water of the first sipe 50 is ejected to the portion where the directional groove 18 is integrated, that is, when water is ejected to a wide space, the water is ejected to a wide space. Is reduced, that is, it is possible to suppress the disturbance of the water flow in the tire circumferential direction of the in-side center circumferential groove 18. Therefore, water flows smoothly along the circumferential direction inside the in-side center circumferential groove 18 to ensure wet performance.

  In addition, the second inclined groove 42 of the out-side second land portion 24 is disposed on the extension line of the first sipe 50 on the arrow OUT direction side, and a wide space is provided on the arrow sipe direction side of the first sipe 50. Therefore, disturbance of the water flow in the tire circumferential direction of the out-side center circumferential groove 16 can be suppressed. Therefore, water flows smoothly along the circumferential direction inside the out-side center circumferential groove 16, and wet performance can be ensured.

  In the present embodiment, the second sipe 56 is formed on the extension line of the third inclined groove 46 on the arrow IN direction side, and the fourth sipe 56 opens to the grounding end 12E on the extension line of the second sipe 56 on the arrow IN direction side. Since the sipe 63A is formed, the water taken into the third inclined groove 46 can be discharged to the outside of the tire through the second sipe 56 and the fourth sipe 63A.

  Thus, in the pneumatic tire 10 of the present embodiment, the tread 12 has the out-side shoulder circumferential groove 14, the out-side center circumferential groove 16, the in-side center circumferential groove 18, and the in-side shoulder circumference as described above. Direction groove 20, first inclined groove 32, second inclined groove 42, third inclined groove 46, notch 54, first sipe 50, second sipe 56, third sipe 60, fourth sipe 63A-C, notch 64, Since the fifth sipe 66 and the lug groove 68 are formed, high wet brake performance can be obtained.

  When the vehicle equipped with the pneumatic tire 10 is traveling straight ahead, the contact pressure near the center of the tread 12 in the tire width direction, that is, near the tire equatorial plane CL tends to be higher than the shoulder side, and near the tire equatorial plane CL. The rigidity of the tread 12 is regarded as important. In the pneumatic tire 10 of the present embodiment, since the center land portion 26 is disposed on the tire equator plane CL, the tire equator of the tread 12 is compared with the case where the center land portion 26 is not disposed on the tire equator plane CL. The rigidity in the vicinity of the surface CL can be ensured, and the stability during straight running can be improved.

  By the way, when a vehicle equipped with the pneumatic tire 10 performs cornering, the pneumatic tire 10 disposed on the radially outer side of the cornering by the action of centrifugal force is pneumatically disposed on the radially inner side of the cornering. A load load becomes larger than that of the tire 10 and a lateral force also acts. Further, in the tread 12 of the pneumatic tire 10 arranged outside the radius of the cornering, the load on the outside (arrow OUT direction side) when the vehicle is mounted is greater than the load on the inside (arrow IN direction side) when the vehicle is mounted. Become. In the pneumatic tire 10 according to the present embodiment, the wide outer side second land portion 24 is arranged outside the narrow center land portion 26 and the inner side second land portion 28 when the vehicle is mounted. Deformation of the center land portion 26 and the in-side second land portion 28 can be suppressed.

  Further, during the cornering, in the center land portion 26, the load on the outer side (arrow OUT direction side) when the vehicle is mounted is relatively larger than the inner side (arrow IN direction side) when the vehicle is mounted. In the pneumatic tire 10 of the present embodiment, the third inclined groove 46 formed in the center land portion 26 has a groove width that gradually decreases from the inner side when the vehicle is mounted to the outer side when the vehicle is mounted. The outer rigidity (bending rigidity and compression rigidity) when mounted on the vehicle is higher than the inner rigidity when mounted on the vehicle, that is, the rigidity on the side where the load increases during cornering is higher. Therefore, the cornering performance can be ensured.

  In the out-side second land portion 24, the groove width of the first inclined groove 32 gradually increases from the arrow IN direction side to the arrow OUT direction side, and the groove width of the second inclined groove 42 increases from the arrow IN direction side to the arrow OUT. Since the width gradually decreases toward the direction side, the rigidity between the arrow IN direction side rigidity and the arrow OUT direction side rigidity of the out-side block land portion 34 between the first inclined groove 32 and the first inclined groove 32. The difference can be eliminated, and the rigidity in the arrow IN direction side and the rigidity in the arrow OUT direction side can be balanced. Thereby, the twist of the out side block land part 34 at the time of the out side block land part 34 grounding can be suppressed, and the partial wear of the out side block land part 34 can be suppressed.

  Since the out side second land portion 24 is divided into a plurality of tire circumferential directions by the plurality of first inclined grooves 32, the outer side second land portion 24 in the tire circumferential direction with respect to the out side second land portion 24 at the time of ground contact is compared with a case where the out side second land portion 24 is not divided. Since the tension is reduced and the drag amount of the out-side second land portion 24 with respect to the road surface is reduced, the rolling resistance is reduced.

  The center land portion 26 does not form a lug groove that crosses the center land portion 26, but forms a third inclined groove 46 and a first sipe 50 that terminate in the land portion. While maintaining, drainage can be improved. Moreover, since the 1st sipe 50 which crosses the center land part 26 was formed in the center land part 26, the rigidity of the center land part 26 is reduced moderately, a ground contact property can improve and it can suppress wear.

  Further, by forming the first sipe 50 across the center land portion 26 in the center land portion 26, the center land portion 26 extending in the tire circumferential direction is divided in the tire circumferential direction. The tensile force in the tire circumferential direction is reduced. As a result, the drag amount of the center land portion 26 with respect to the road surface is reduced, so that the rolling resistance can be reduced.

  In the in-side second land portion 28, the lug groove that crosses the in-side second land portion 28 is not formed, and the notch 54, the second sipe 56, and the third sipe 60 are formed. While ensuring the rigidity, it is possible to improve drainage and improve wet brake performance. In addition, since the second sipe 56 that crosses the in-side second land portion 28 is formed in the in-side second land portion 28, the rigidity of the in-side second land portion 28 is moderately reduced, and the ground contact property is improved to suppress wear. can do.

  Furthermore, since the in-side second land portion 28 extending in the tire circumferential direction is divided in the tire circumferential direction by forming the second sipe 56 that crosses the in-side second land portion 28 in the in-side second land portion 28, The tensile force in the tire circumferential direction with respect to the in-side second land portion 28 is reduced. As a result, the drag amount of the in-side second land portion 28 with respect to the road surface is reduced, so that the rolling resistance can be reduced. In the in-side second land portion 28 of the present embodiment, a third sipe 60 is formed between the second sipe 56 and the second sipe 56, and the in-side second land portion 28 is further divided in the tire circumferential direction. Therefore, the drag amount of the in-side second land portion 28 can be further reduced, and the rolling resistance can be further reduced.

  Further, since the third sipe 60 and the notch 54 are separated from each other in the in-side second land portion 28, the rigidity of the land portion of the in-side second land portion 28 can be ensured as compared with the case where both are connected. .

  Further, since the second sipe 56 of the in-side second land portion 28 is disposed on the extension line of the third inclined groove 46 formed in the center land portion 26 and inclined with respect to the tire width direction, the third inclined groove 46 and The second sipe 56 is not lined up in the tire width direction, and the portion where the third inclined groove 46 is formed and the portion where the second sipe 56 is formed do not touch the road surface at the same time, so noise during driving is suppressed. be able to.

  In addition, when the vehicle equipped with the pneumatic tire 10 corners, the pneumatic tire 10 disposed on the radially outer side of the cornering by the action of centrifugal force causes the air disposed on the radially inner side of the cornering. The load burden is greater than that of the entering tire 10. Further, the tread 12 of the pneumatic tire 10 disposed outside the radius of the cornering has a larger ground contact area in the outer portion when the vehicle is mounted than in the inner portion when the vehicle is mounted. For this reason, when cornering a wet road surface, drainage of the outer portion of the tread 12 is important when the vehicle is mounted. In the present embodiment, since the lug groove 68 that is not a sipe is disposed on the out-side shoulder land portion 22 that is disposed outside when the vehicle is mounted, the drainage performance during cornering can be improved by the lug groove 68. .

In the in-side shoulder land portion 30, since a plurality of fourth sipe 63 extending in the direction crossing the in-side shoulder land portion 30 are formed in the tire circumferential direction, the rigidity of the in-side shoulder land portion 30 is appropriately reduced, It is possible to improve wear and suppress wear. Furthermore, since the in-side shoulder land portion 30 extending in the tire circumferential direction is divided in the tire circumferential direction, pulling in the tire circumferential direction with respect to the in-side shoulder land portion 30 at the time of ground contact is reduced, thereby the in-side shoulder with respect to the road surface. Since the drag amount of the land portion 30 is reduced, the rolling resistance can be reduced.
The pneumatic tire 10 of this embodiment is suitable for mounting on, for example, an ordinary passenger car, but may be mounted on other types of vehicles.

[Second Embodiment]
Next, a pneumatic tire 10 according to a second embodiment of the present invention will be described with reference to FIGS. 11 and 12. In addition, the same code | symbol is attached | subjected to the same structure as 1st Embodiment, and the description is abbreviate | omitted. As shown in FIG. 11, the pneumatic tire 10 of the present embodiment is different from the pneumatic tire 10 of the first embodiment in the configuration of the in-side shoulder land portion 30, and the other configurations are the same. Yes. In the in-side shoulder land portion 30 of the pneumatic tire 10 of the present embodiment, a plurality of depressions 74 are arranged in a staggered manner along the tire circumferential direction.

  As shown in FIGS. 12A and 12B, the depression 74 is formed at the first depression 76 having an oval shape (substantially oval) in a tread plan view and the bottom of the first depression 76. And a second recess 78 that is circular in a plan view of the tread, and a second recess 78 that is deeper than the first recess 74 is integrated with the first recess 74 in the direction of the arrow IN. Is formed.

  As shown in FIGS. 12A and 12C, the first depression 74 is directed from the end (edge of the opening) on the width direction side (short axis direction side) toward the center in the width direction. It is gradually formed deeper (toward the long axis of the ellipse), and the cross-sectional shape of the bottom is a substantially arc shape. In addition, a long axis is an axis | shaft which points to the largest dimension of an ellipse shape. The short axis is an axis in a direction intersecting with the long axis.

  As shown in FIG. 11, a plurality of fine grooves 80 extending along the tire circumferential direction are formed in the in-side shoulder land portion 30 on the arrow OUT direction side of the recess 74 at intervals in the tire circumferential direction. In addition, a sipe 82 extending from one end of the narrow groove 80 on the arrow A direction side to the arrow OUT direction side is formed.

(Function, effect)
Next, the operation and effect of the pneumatic tire 10 of the present embodiment will be described.
In the pneumatic tire 10 of the present embodiment, since the plurality of depressions 74 are arranged in the in-side shoulder land portion 30 at a constant interval in the tire circumferential direction in a zigzag pattern, While ensuring rigidity, compression rigidity can be reduced moderately and the rigidity of the in-side shoulder land portion 30 can be made uniform. Thereby, the partial wear of the in-side shoulder land portion 30 can be suppressed. In addition, since the depression 34 does not excessively reduce the rigidity of the land portion compared to the groove, it is possible to ensure the rigidity necessary for the in-side shoulder land portion 30.

  In addition, since the in-side shoulder land portion 30 is not formed with a groove that crosses the in-side shoulder land portion 30 in the tire width direction, a higher land portion rigidity is obtained as compared with the case where the groove is formed. ing. Therefore, the rigidity of the tread 12 in the direction of the arrow IN, that is, the inner side in the vehicle width direction when the vehicle is mounted can be secured, and the pneumatic tire in which the rigidity in the vehicle width direction when the tread 12 is mounted is emphasized. This is suitable for a relatively heavy vehicle such as an RV vehicle for which it is desired to install the vehicle 10.

  The depression 74 can take in water between the in-side shoulder land portion 30 and the road surface when traveling on a wet road surface, and can cut a water film between the in-side shoulder land portion 30 and the road surface at the edge portion of the depression 74. Therefore, the water film is excellent in water removal performance, and the wet brake performance can be improved. Further, the depression 74 has an oval shape in plan view of the tread, and the major axis of the ellipse is inclined with respect to the tire circumferential direction. Therefore, the edge in the tire width direction is compared with a perfect circle depression having the same area. Since the component (the length of the edge projected in the tire circumferential direction) becomes longer, the wet brake performance can be further improved.

  Further, the depression 74 is formed in an oval shape in a tread plan view, and since there is no corner portion, it is difficult for stress to concentrate and generation of cracks and the like can be suppressed. In addition, the ground contact property of the recess portion edge is improved and the wear resistance is also improved by suppressing the stress concentration.

  Although one embodiment of the present invention has been described above, the present invention is not limited to the above, and other various modifications can be made without departing from the spirit of the present invention. It is.

DESCRIPTION OF SYMBOLS 10 ... Pneumatic tire, 12 ... Tread, 14 ... Out side shoulder circumferential groove, 16 ... Out side center circumferential groove, 18 ... In side center circumferential groove, 20 ... In side shoulder circumferential groove, 22 ... Out side Shoulder land portion, 24 ... Out side second land portion, 26 ... Center land portion, 28 ... In side second land portion, 30 ... In side shoulder land portion, 32 ... First inclined groove, 34 ... Out side block land portion, 42 ... 2nd inclined groove, 46 ... 3rd inclined groove, 50 ... 1st sipe, 54 ... Notch, 56 ... 2nd sipe, 60 ... Sipe, CL ... Tire equatorial plane

Claims (5)

A plurality of land portions provided on the tread and partitioned by a plurality of circumferential grooves extending along the tire circumferential direction;
In the first land portion of the plurality of land portions, the plurality of land portions extend while being inclined with respect to the tire width direction and spaced apart in the tire circumferential direction, and grooves are formed from one side to the other side in the tire width direction. A first inclined groove that gradually increases in width and divides the block-shaped land portion;
The block-shaped land portion is disposed on the one side of the block-shaped land portion, extends from one side in the tire width direction toward the other side and inclines with respect to the tire width direction, and from one side in the tire width direction. A second inclined groove in which the groove width gradually decreases toward the other side, and the end portion on the other side in the tire width direction terminates in the block-shaped land portion;
A second land portion disposed on one side of the tire land direction on the tire equatorial plane and narrower than the first land portion;
The second land portion is disposed on the one side of the second land portion, extends from one side in the tire width direction toward the other side and inclines with respect to the tire width direction, and one in the tire width direction. A third inclined groove in which the groove width gradually decreases from the side toward the other side, and the end portion on the other side in the tire width direction terminates in the second land portion;
Pneumatic tire having   2. The air according to claim 1, wherein a first sipe that crosses the second land portion is formed in the second land portion between the third inclined groove and the third inclined groove. Enter tire. A third land portion disposed on one side of the tire width direction of the second land portion;
A notch provided on an end of the third land portion on the other side in the tire width direction and disposed on an extension line of the first sipe;
The pneumatic tire according to claim 2, comprising:   The pneumatic tire according to claim 3, wherein a second sipe is formed on the third land portion on an extension line of the third inclined groove of the second land portion.   A third sipe that extends in a direction intersecting with the longitudinal direction of the third land portion and that is separated from the notch is formed on the third land portion on the side opposite to the side where the notch is formed. The pneumatic tire according to claim 3 or 4, wherein the pneumatic tire is used.

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