JP2013133083A - Pneumatic tire - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a pneumatic tire that achieves improvement in wet performance while ensuring rigidity of the tire mounting outside.SOLUTION: A plurality of circumferential main grooves extending along the tire circumferential direction are formed in a tread 16. An outer rib 46, to which a land part continues in the tire circumferential direction, is formed on the outer side of a vehicle in tire mounting than the plurality of circumferential main grooves. A fourth lug groove 42 is extended toward the outer rib 46 from an outermost circumferential main groove 24 formed on the outermost side of the vehicle in tire mounting, of the plurality of circumferential main grooves. A shoulder circumferential minute groove 28 is formed on the outer side in the tire mounting than the outermost circumferential main groove 24. The groove depth H3 of the shoulder circumferential minute groove 28 is made shallower than the groove depth H0 of the outermost circumferential main groove 24 and the depth H4 of the fourth lug groove 42.

Description

  The present invention relates to a pneumatic tire, and more particularly to a pneumatic tire having a plurality of tread patterns formed in the tire circumferential direction.

  Normally, during cornering of a pneumatic tire, the ground pressure of the pneumatic tire is higher on the outside of the vehicle than on the inside of the vehicle. Therefore, in order to improve cornering performance, it is required to increase the rigidity of the tread tire mounting outside. On the other hand, it is necessary to consider the drainage performance when traveling on a wet road surface. For this reason, in the pneumatic tire disclosed in Patent Document 1, a circumferential narrow groove having a groove width narrower than the tire main groove is formed outside the tire main groove in the tire width direction (tire mounting outer side). The direction narrow groove is connected with the lateral groove to ensure drainage.

  However, it is possible to cope with a more severe environment by further improving the drainage performance in the lateral groove.

JP 2010-58781 A

  The present invention has been made in view of the above-described facts, and an object of the present invention is to provide a pneumatic tire with improved wet performance while ensuring rigidity on the tire mounting outer side.

  A pneumatic tire according to claim 1 of the present invention is a tire formed at a tread portion and extending along the tire circumferential direction, and a tire when the vehicle is mounted more than the plurality of circumferential main grooves. An outer rib formed on the outer side of the tire and having land portions extending in the tire circumferential direction, and the outermost circumferential main groove formed on the outermost tire outer side of the plurality of circumferential main grooves when the vehicle is worn. A lug groove that extends toward the rib and terminates on the outermost circumferential main groove side with respect to the tire grounding end on the tire mounting outer side, and is formed on the outer rib side with respect to the outermost circumferential main groove, A shoulder circumferential narrow groove extending along the tire circumferential direction and having a groove depth shallower than the outermost circumferential main groove and the lug groove.

  In the pneumatic tire according to claim 1, a plurality of circumferential main grooves extending along the tire circumferential direction are formed in the tread. And the outer side rib is formed in the tire outer side at the time of vehicle mounting | wearing. In the outer rib, the land portion is continuous in the tire circumferential direction on the tire contact end side with respect to the lug groove, and rigidity is ensured.

  Here, the inside in the tire width direction (inside the vehicle) when the tire is attached to the vehicle is referred to as “tire inside”, and the outside in the tire width direction (inside the vehicle) when the tire is attached to the vehicle is “ It is called “tire-mounted outside”. The land portion is a portion defined by a groove in the tread portion, and includes a rib and a block.

  On the other hand, a lug groove is extended toward the outer rib from the outermost circumferential main groove formed on the outermost tire mounting side among the plurality of circumferential main grooves. With this lug groove, water on the outer rib side can be caught and flowed to the outermost circumferential main groove, and the drainage of the outer rib can be improved. In addition, since this lug groove terminates on the outermost circumferential main groove side from the tire ground contact end, the outer side in a state where the land portion is continuous on the tire equatorial plane side from the tire ground contact end outside the tire mounting. A rib can be arrange | positioned and a cornering performance can be improved effectively.

  Moreover, since the shoulder circumferential direction fine groove is formed in the outer side rib side rather than the outermost circumferential direction main groove, drainage can be further improved. Further, since the shoulder circumferential narrow groove has a groove depth shallower than that of the outermost circumferential main groove and lug groove, it is possible to suppress a decrease in tire rigidity on the outer rib side in the tread portion.

  Furthermore, since the shoulder circumferential direction narrow groove is formed, buckling during cornering can also be suppressed. Buckling is a phenomenon in which the tire mounting upper side falls down to the tire mounting outside during cornering, and the ground pressure on the tire mounting inner side is released. By forming the shoulder circumferential narrow groove, the land portion on the tire wearing inner side adjacent to the shoulder circumferential narrow groove can be easily grounded, and a decrease in grip force on the tire wearing inner side can be suppressed.

  The pneumatic tire of the present invention can be applied to both a left-right asymmetric tread pattern in which the inside and outside of the tire are specified and a left-right symmetrical tread pattern.

  The pneumatic tire according to claim 2 of the present invention is characterized in that a corner between the groove wall of the shoulder circumferential narrow groove and the tread surface is larger than 90 degrees.

  Here, as a method of making the corner between the groove wall of the shoulder circumferential narrow groove and the tread surface larger than 90 degrees, the angle between the groove wall and the tread surface with the groove wall from the groove bottom to the tread surface being flush with each other. The angle may be larger than 90 degrees, the angle between the groove wall and the groove bottom is 90 degrees, and the corner between the groove wall and the tread is chamfered between the tread and the groove wall. It may be larger than 90 degrees.

  Thus, the rigidity of the tread in the vicinity of the shoulder circumferential narrow groove can be reduced by making the corner between the groove wall of the shoulder circumferential narrow groove and the tread larger than 90 degrees. Therefore, at the time of cornering, it is possible to improve the ground contact property on the tire wearing inner side of the shoulder circumferential narrow groove.

  The pneumatic tire according to claim 3 of the present invention is characterized in that the lug groove and the shoulder circumferential narrow groove intersect each other.

  According to the above configuration, since the lug groove protrudes to the outer rib side from the shoulder circumferential narrow groove, the water captured by the projecting portion projecting outward from the shoulder circumferential narrow groove of the lug groove in the tire width direction is removed from the shoulder circumference. Drainage can be performed using both the directional narrow groove and the outermost circumferential main groove, and drainage can be performed efficiently.

  As described above, since the pneumatic tire according to claim 1 has the above-described configuration, it is possible to improve the drainage performance while ensuring the rigidity on the outside of the vehicle when the tire is mounted.

  Since the pneumatic tire according to claim 2 has the above-described configuration, it is possible to improve the ground contact property on the tire wearing inner side of the shoulder circumferential narrow groove during cornering.

  Since the pneumatic tire according to claim 3 has the above-described configuration, it is possible to drain the water captured on the outer rib side using both the shoulder circumferential narrow groove and the outermost circumferential main groove, and efficiently. Drainage can be performed.

It is tire radial direction sectional drawing of the pneumatic tire which concerns on 1st Embodiment. It is a top view of the tread of the pneumatic tire concerning a 1st embodiment. It is a partially expanded plan view of the tread of the pneumatic tire according to the first embodiment. It is sectional drawing of the AA line of FIG. It is sectional drawing of the BB line of FIG. It is sectional drawing of the part corresponding to the AA line of FIG. 2 of the pneumatic tire which concerns on the modification of 1st Embodiment. It is a top view of the tread of the pneumatic tire concerning a 2nd embodiment. It is a top view of the tread of the pneumatic tire concerning a 3rd embodiment. It is a top view of the tread of the pneumatic tire concerning a 4th embodiment.

  Hereinafter, a pneumatic tire 10 according to a first embodiment of the present invention will be described with reference to the drawings. The arrow IN in the figure indicates the inside (hereinafter referred to as “tire wearing”) when the tire is mounted on the vehicle (hereinafter referred to as “tire wearing inside”), and the arrow OUT indicates the outside (when mounted on the tire). Hereinafter, it is referred to as “tire outer side”). The alternate long and short dash line CL indicates the tire equator plane.

  As shown in FIG. 1, the pneumatic tire 10 of the present embodiment includes a pair of bead portions 12, a pair of sidewall portions 14, and a tread portion 16. In the bead portion 12, at least one annular bead core 12A is embedded. A carcass 18 is provided between the pair of bead cores 12A so as to straddle a toroidal shape. The carcass 18 is wound back from the inside to the outside with respect to the bead core 12A. A belt layer 19 is provided on the outer side of the carcass 18 in the tire radial direction.

  FIG. 2 shows the tread portion 16 of the pneumatic tire 10. The tire ground contact edge 16E of the tread portion 16 attaches the pneumatic tire 10 to a standard rim stipulated in JATMA YEAR BOOK (Japan Automobile Tire Association Standard, 2011 edition), and is applicable for JATMA YEAR BOOK. This is when the maximum load capacity is loaded with 100% internal pressure of the air pressure (maximum air pressure) corresponding to the maximum load capacity (bold load in the internal pressure-load capacity correspondence table) in the ply rating. When the TRA standard or ETRTO standard is applied at the place of use or manufacturing, the respective standards are followed.

  The pneumatic tire 10 of the present embodiment has a pattern shape that is asymmetrical with respect to the tire equatorial plane CL, and is mounted so that the left side of the drawing is the tire mounting inner side and the right side of the drawing is the tire mounting outer side. The tire rotation direction is preferably mounted so that it is the direction indicated by the arrow R (the lower side in the figure is the stepping side and the upper side is the kicking side). Regarding the tire rotation direction, it is not always necessary to mount the tire with the aforementioned directionality, and the front and rear direction may be mounted in reverse.

  In the tread portion 16 of the pneumatic tire 10 of the present embodiment, an innermost circumferential main groove 20 as a plurality of (three in the present embodiment) circumferential main grooves extending along the tire circumferential direction, a central circumferential direction. A main groove 22 and an outermost circumferential main groove 24 are formed.

  The innermost circumferential main groove 20 is formed on the innermost side of the tire mounting among the three circumferential main grooves. The central circumferential main groove 22 is formed on the tire mounting outer side than the innermost circumferential main groove 20 and on the tire mounting inner side than the tire equatorial plane CL. The outermost circumferential main groove 24 is formed on the tire mounting outer side than the central circumferential main groove 22 and on the tire mounting outer side than the tire equatorial plane CL.

  An inner circumferential narrow groove 26 is formed on the tire mounting inner side than the innermost circumferential main groove 20. The inner circumferential narrow groove 26 is narrower than the innermost circumferential main groove 20 and has a shallow groove depth.

  A shoulder circumferential narrow groove 28 is formed outside the outermost circumferential main groove 24 on the tire mounting outer side. The groove width W3 at the groove bottom of the shoulder circumferential narrow groove 28 is formed to be narrower than the groove width W0 of the outermost circumferential main groove 24. Further, the groove depth H3 of the shoulder circumferential narrow groove 28 is formed to be shallower than the groove depth H0 of the outermost circumferential main groove 24. Each of the groove walls 28A and 28B constituting the shoulder circumferential narrow groove 28 has a flush shape, and an angle with the groove bottom (and an angle with the tread surface) is larger than 90 degrees. Accordingly, the shoulder circumferential narrow groove 28 has a groove width that increases from the groove bottom toward the tread surface. The angle between the groove walls 28A, 28B and the tread surface is preferably within a range of 100 degrees to 160 degrees.

  The shoulder circumferential narrow groove 28 is narrower than the three circumferential main grooves (the innermost circumferential main groove 20, the central circumferential main groove 22, and the outermost circumferential main groove 24). It is distinguished from the circumferential main groove in that the groove depth is shallow.

  An inner rib 30 is formed on the shoulder side of the tread portion 16 with respect to the inner circumferential narrow groove 26. The inner rib 30 is formed with a first lug groove 30A having a constant width that opens in the inner circumferential narrow groove 26 and extends in the tire width direction from the inner circumferential narrow groove 26 toward the shoulder on the tire mounting inner side. . The first lug groove 30A terminates on the tire equatorial plane CL side with respect to the tire ground contact end 16E on the tire mounting inner side. Further, the inner rib 30 is formed with a second lug groove 30B having a constant width that is spaced apart from the inner circumferential narrow groove 26 and extends in the tire width direction. The second lug groove 30B extends across the tire ground contact edge 16E and is formed between the two first lug grooves 30A in the tire circumferential direction. The first lug groove 30 </ b> A and the second lug groove 30 </ b> B are disposed so as to partially overlap each other when viewed from the tire circumferential direction. Therefore, in the inner rib 30, no land portion that is linearly continuous in the tire circumferential direction is formed.

  A first rib 32 is formed between the inner circumferential narrow groove 26 and the innermost circumferential main groove 20. No groove is formed in the first rib 32. The rib width of the first rib 32 is narrower than other ribs formed on the tread portion 16.

  A second rib 34 is formed between the innermost circumferential main groove 20 and the central circumferential main groove 22. A second lug groove 36 is formed in the second rib 34. The second lug groove 36 opens to the innermost circumferential main groove 20 and extends from the innermost circumferential main groove 20 toward the central circumferential main groove 22. The second lug groove 36 does not open to the central circumferential main groove 22 and terminates in the second rib 34. Accordingly, a land portion linearly continuous in the tire circumferential direction is formed on the side of the second rib 34 close to the tire equatorial plane CL.

  The second lug groove 36 is slightly inclined with respect to the tire width direction. The acute angle side (upper side of the second lug groove 36 in FIG. 2) of the corners formed between the innermost circumferential main groove 20 and the second lug groove 36 is chamfered, and the chamfered portion 36M is formed. Is formed. As for the 2nd lug groove 36, the center circumferential direction main groove 22 side is made into the front-end | tip part 36S whose groove width is narrower than the innermost circumferential direction main groove 20 side. The distal end portion 36S is configured to be narrow by forming an R step portion 36D in the groove wall on the side where the chamfered portion 36M is not formed. The R step portion 36D has an R shape with a smooth connection corner with the tip portion 36S. The groove bottom of the second lug groove 36 is deepest on the innermost circumferential main groove 20 side, and gradually becomes shallower toward the tip 36S side.

  A third rib 38 is formed between the central circumferential main groove 22 and the outermost circumferential main groove 24. The tire equatorial plane CL is disposed on the central circumferential main groove 22 side on the third rib 38. A sipe 38S is formed on the third rib 38. The sipe 38S opens to the outermost circumferential main groove 24 and extends from the outermost circumferential main groove 24 toward the central circumferential main groove 22 side. The sipe 38S has a groove width that is closed by grounding. The groove walls constituting the sipe 38S are chamfered along the sipe 38S to form chamfered portions 38A and 38B. The sipe 38 </ b> S does not open to the central circumferential main groove 22 and terminates in the third rib 38. Therefore, a land portion that is linearly continuous in the tire circumferential direction is formed on the end portion of the third rib 38 on the side close to the tire equatorial plane CL.

  A fourth land portion 40 is formed between the outermost circumferential main groove 24 and the shoulder circumferential narrow groove 28. Further, an outer rib 46 is formed on the tire grounding end 16E side on the outer side of the tire from the fourth land portion 40. The fourth land portion 40 is formed with a fourth lug groove 42 extending from the outermost circumferential main groove 24 toward the tire mounting outer side. The fourth lug groove 42 is linear, one end 42A is opened in the outermost circumferential main groove 24, crosses the shoulder circumferential narrow groove 28, and the other end (hereinafter, this other end is referred to as "terminal portion 42B"). ) Extends into the outer rib 46. One end 42A of the fourth lug groove 42 is disposed as an extension of the sipe 38S. Further, the fourth lug groove 42 is inclined in the same direction as the sipe 38 </ b> S, and constitutes a design that is continuous with the sipe 38 </ b> S via the outermost circumferential main groove 24.

  The fourth lug groove 42 intersects the shoulder circumferential narrow groove 28 and terminates at a terminal portion 42 </ b> B in the outer rib 46. The end portion 42B is disposed closer to the tire equatorial plane CL than the tire ground contact end 16E on the tire mounting outer side. The outer rib 46 has a land portion that continues linearly in the tire circumferential direction. As shown also in FIG. 3, the groove width of the fourth lug groove 42 is W1 that is the narrowest at one end 42 </ b> A that is an opening portion to the outermost circumferential main groove 24, and the end portion 42 </ b> B in the outer rib 46. W2 is the widest. The fourth lug groove 42 is formed so as to gradually expand from the one end 42A toward the terminal end 42B.

  As shown in FIG. 4, the groove depth H4 of the fourth lug groove 42 is shallower than the groove depth H0 of the outermost circumferential main groove 24 and deeper than the groove depth H3 of the shoulder circumferential narrow groove 28. It has become. At the intersection 45 where the fourth lug groove 42 and the shoulder circumferential narrow groove 28 intersect (see FIG. 2), the groove depth is H4. Accordingly, the bottom of the shoulder circumferential narrow groove 28 is deeper than the other portions of the shoulder circumferential narrow groove 28 at the intersection 45. In FIG. 4, the tire ground contact surface is schematically shown as a plane in order to facilitate comparison of groove depths.

  As shown in FIG. 5, a groove bottom upper portion 44 in which the groove is raised is formed on the one end 42 </ b> A side of the fourth lug groove 42. The groove depth of the groove bottom upper portion 44 is shallower than the groove depth H4 of the fourth lug groove 42, and the groove bottom upper portion 44 is formed from one end 42A to the vicinity of the center of the fourth land portion 40. In FIG. 5 as well, the tire ground contact surface is schematically shown as a plane in order to facilitate comparison of the groove depth.

  In the fourth land portion 40 and the outer rib 46, the chamfered portions 40M, respectively, are formed on the acute side of the corner portions of the intersecting portion 45 formed between the fourth lug groove 42 and the shoulder circumferential narrow groove 28. 46M is formed.

  A wear indicator 48 is formed on the extended portion of the outer rib 46 from the fourth lug groove 42. The wear indicator 48 is composed of two holes formed apart from the terminal end portion 42B of the fourth lug groove 42. With this wear indicator 48, the wear state of the outer rib 46 can be known separately from the wear indicator normally provided in the tire circumferential main groove.

  Next, the effect | action of the pneumatic tire 10 of this embodiment is demonstrated.

  In the pneumatic tire 10 of the present embodiment, the innermost circumferential main groove 20, the central circumferential main groove 22, and the outermost circumferential main groove 24 are formed in the tread portion 16, so that basic drainage is performed. , Straight running stability during dry and wet running.

  Further, on the tread portion 16 of the pneumatic tire 10 of the present embodiment, an outer rib 46 having a land portion continuous in the tire circumferential direction is disposed on the tire mounting outer side. Accordingly, the rigidity on the outer side of the tire is ensured and the cornering performance can be enhanced. Further, the fourth lug groove 42 extending to the outer rib 46 terminates without reaching the tire ground contact end 16E. Therefore, the rigidity of the outer rib 46 can be effectively ensured. Further, the groove width of the fourth lug groove 42 is the maximum W2 in the outer rib 46. As a result, water on the outer rib 46 side can be captured and flowed to the outermost circumferential main groove 24 at a portion where the groove width is wide, and drainage on the outer rib 46 side can be improved.

  The fourth lug groove 42 has a groove bottom upper portion 44 on the one end 42A side. Therefore, the rigidity of the fourth land portion 40 can be maintained while ensuring the drainage. The bottom upper portion 44 is formed on the one end 42A side. Therefore, the groove depth on the tire mounting outer side is ensured, and more water can be captured on the tire mounting outer side.

  In the pneumatic tire 10 of the present embodiment, the shoulder circumferential narrow groove 28 is formed adjacent to the outer rib 46. Therefore, the outer rib 46 can be drained by the shoulder circumferential narrow groove 28, and drainage can be improved. On the other hand, the shoulder circumferential narrow groove 28 is narrower than the outermost circumferential main groove 24 and narrower than the outermost circumferential main groove 24 and the fourth lug groove 42. Therefore, a decrease in rigidity of the outer rib 46 can be suppressed.

  Further, by forming the shoulder circumferential narrow groove 28, buckling during cornering can also be suppressed. Buckling here is a phenomenon in which the tread surface floats off the road surface and the ground pressure inside the tire is released while the tire is about to fall outside with the fulcrum near the outside edge of the tire when cornering. . In the pneumatic tire 10 of the present embodiment, since the shoulder circumferential narrow groove 28 is formed, the bending rigidity of the tread surface is lowered, so that the tire mounting inner side, particularly the land portion 40 is easily grounded, and the tire It is possible to suppress a decrease in grip strength inside the mounting.

  The angle between the tread surface of the fourth land portion 40 and the tread surface of the outer rib 46 of the groove walls 28A, 28B of the shoulder circumferential narrow groove 28 is set to be greater than 90 degrees. Therefore, the rigidity of the tread surface in the vicinity of the shoulder circumferential narrow groove 28 can be reduced, and the grounding property on the tire wearing inner side of the shoulder circumferential narrow groove 28 can be improved during cornering.

  In the present embodiment, the groove walls 28A, 28B of the shoulder circumferential narrow groove 28 are each flush with each other, and the corner between the tread surface of the fourth land portion 40 and the tread surface of the outer rib 46 is more than 90 degrees. However, the angle between the groove walls 28A and 28B and the tread surface may be made larger than 90 degrees by another method. For example, as shown in FIG. 6, the angle between the groove wall 28A, 28B and the groove bottom is 90 degrees, and the angle between the groove wall and the tread surface is a chamfer M between the tread surface and the groove wall 28A, 28B. The part may be larger than 90 degrees.

  Further, in the present embodiment, since the sipe 38S is formed on the third rib 38, it is possible to suppress uneven wear at the rib end of the third rib 38 on the side far from the tire equatorial plane CL. That is, in the third rib 38, since the rib end on the outermost circumferential main groove 24 side is far from the tire equatorial plane CL, the tire circumferential length becomes short and dragging easily occurs. In other words, since the sipe 38S is formed, drag is suppressed and uneven wear can be suppressed. Moreover, since the sipe 38S does not open to the central circumferential main groove 22, a land portion that is linearly continuous in the tire circumferential direction is formed. Therefore, in the third rib 38, rigidity on the side close to the tire equatorial plane CL is ensured, and steering stability can be maintained. Further, since the chamfered portions 38A and 38B are formed along the sipe 38S, chunks such as chipping or peeling of the rubber around the sipe 38S in the tire circumferential direction can be suppressed.

  Moreover, in this embodiment, since the 2nd lug groove 36 is formed in the 2nd rib 34, drainage property can be improved. Further, the second lug groove 36 has a narrower groove width toward the tire equatorial plane CL side and a shallower groove depth, so that the rigidity on the higher contact pressure side is maintained and the occurrence of chunks is suppressed. be able to. Further, since the chamfered portion 36M is formed on the acute angle side of the corner portion formed between the innermost circumferential main groove 20 and the second lug groove 36, rubber is chipped or peeled off at the corner portion, etc. Can be suppressed. Further, the second lug groove 36 is opened in the innermost circumferential main groove 20 on the side far from the tire equatorial plane CL. In general, the tire circumferential length of the tread portion is longer as it is closer to the tire equatorial plane CL, and the tire contact pressure is higher. Therefore, dragging at the rib end of the second rib 34 on the side far from the tire equatorial plane is suppressed, and uneven wear can be suppressed. Further, since the second lug groove 36 does not open to the central circumferential main groove 22, a land portion linearly continuous in the tire circumferential direction is formed at the rib end on the central circumferential main groove 22 side. Therefore, rigidity is ensured on the side close to the tire equatorial plane CL, and steering stability can be maintained.

  In the present embodiment, chamfered portions 40M and 46M are respectively formed on the acute side of the corner portions of the intersecting portion 45 formed between the fourth lug groove 42 and the shoulder circumferential narrow groove 28. Yes. Therefore, chunks such as chipping or peeling of rubber at the corners can be suppressed.

  In the present embodiment, the groove width W1 on the one end 42A side of the fourth lug groove 42 is wider than the groove width W2 of the terminal end portion 42B. However, it is not always necessary to do this, and the groove widths W1 and W2 are not necessarily required. Or a configuration in which the groove width W1 is wider than W2.

  Further, in the present embodiment, the configuration in which the fourth lug groove 42 intersects the shoulder circumferential narrow groove 28 and reaches the outer rib 46 has been described, but the fourth lug groove 42 is not necessarily the shoulder circumferential narrow groove 28. There is no need to cross. As shown in the second embodiment of FIG. 7, it may be configured such that it only opens to the shoulder circumferential narrow groove 28 and does not protrude toward the outer rib 46 side. Moreover, you may make it the structure which terminates in the 4th land part 40 before the shoulder circumferential direction fine groove 28. FIG.

  In each of the above embodiments, the fourth lug groove 42 is inclined with respect to the tire width direction. However, the fourth lug groove 42 is not necessarily inclined with respect to the tire width direction. You may arrange | position in parallel with a direction. In consideration of non-designation of the tire rotation direction, the inclination of the fourth lug groove 42 with respect to the tire width direction is preferably in the range of 0 to 45 degrees.

  In the present embodiment, a left-right asymmetric tread pattern has been described as an example. However, the present invention may be applied to a left-right symmetrical tread pattern. In this case, as shown in the third embodiment in FIG. 8, the right side portion of the central circumferential main groove 22 of the tread portion 16 in FIG. It can be configured to be arranged. The tire equatorial plane CL is disposed at the center of the central circumferential main groove 22. Further, as shown in the fourth embodiment in FIG. 9, the right side portion of the tread portion 16 in FIG. 2 with respect to the central circumferential main groove 22 can be arranged on the left side with point symmetry.

  As described above, when the tread pattern is symmetric, the rigidity on the inner side of the tire is increased similarly to the outer side of the tire. As in the first embodiment, by using a tread pattern that is asymmetrical to the left and right, especially in a vehicle body provided with a negative camber, the rigidity on the inner side of the tire mounting does not become too high. The handling feeling during running is improved.

10 Pneumatic tire 16E Tire ground contact edge 16 Tread portion 24 Outermost circumferential main groove 28 Shoulder circumferential narrow groove 28A Groove wall 28B Groove wall 42 Fourth lug groove 42A One end 42B End portion 45 Intersection 46 Outer rib H0 Groove depth H3 Groove depth H4 Groove depth

Claims (3)

A plurality of circumferential main grooves formed in the tread portion and extending along the tire circumferential direction;
An outer rib formed on the outer side of the tire mounting at the time of vehicle mounting than the plurality of circumferential main grooves, and a land portion continuing in the tire circumferential direction;
Of the plurality of circumferential main grooves, the outermost circumferential main groove formed at the outermost tire mounting outer side at the time of vehicle mounting is extended toward the outer rib, and the outermost tire grounding end is more than the outermost tire grounding end. Lug groove terminating on the outer circumferential main groove side;
A shoulder circumferential narrow groove formed on the outer rib side of the outermost circumferential main groove, having a shallower depth than the outermost circumferential main groove and the lug groove, and extending along the tire circumferential direction;
Pneumatic tire with   The pneumatic tire according to claim 1, wherein a corner between the groove wall of the shoulder circumferential narrow groove and the tread surface is larger than 90 degrees.   The pneumatic tire according to claim 1 or 2, wherein the lug groove and the shoulder circumferential narrow groove intersect each other.

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