JP4518640B2 - Pneumatic tire - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
  The present invention relates to a pneumatic tire, and more particularly to a pneumatic tire having a block pattern that improves on-road performance and pattern noise and can be compatible with off-road and on-snow performance.
[0002]
[Prior art]
  In passenger and four-wheel drive tires, to improve off-road driving performance,As shown in FIG.The tread 100 basically has a circumferential groove 102 extending in a zigzag shape in the circumferential direction in order to obtain edge components both vertically and horizontally, and a block having a transverse groove 104 extending in the tire axial direction from the apex or side of the zigzag. A pattern configuration is generally adopted.
[0003]
  The tread pattern will be described in detail. The tread 100 includes a circumferential groove 106 formed between the pair of circumferential grooves 102, which is parallel to the tire equatorial plane CL and is linearly formed with a constant width. A pair is provided.
[0004]
  In a region sandwiched between the pair of circumferential grooves 106, a large number of lateral grooves 108 that are inclined with respect to the tire circumferential direction are formed in the tire circumferential direction, thereby defining a plurality of center blocks 110.
[0005]
  The center block 110 is formed with a narrow sub-groove 112 inclined in the opposite direction to the lateral groove 108 to form two sub-blocks. In the center block 110, a plurality of sipes 113 are formed.
[0006]
  In the area sandwiched between the circumferential groove 102 and the circumferential groove 106, a large number of second blocks 114 are formed. In the second block 114, a narrow sub-groove 116 that is inclined in the same direction as the lateral grooves 104 is formed. Two sub-blocks are formed. In the second block 114, a plurality of sipes 118 are formed.
[0007]
  A large number of shoulder blocks 120 are formed outside the circumferential groove 102 in the tire width direction. The shoulder block 120 is formed with sub-grooves 122 and a plurality of sipes 124 that are inclined in the same direction as the lateral grooves 104.
[0008]
  The lateral groove 108 and the lateral grooves 104 on both the left and right sides are both inclined upward. Further, the center block 110, the second block 114, and the shoulder block 120 are arranged with a phase difference in the tire circumferential direction between adjacent blocks.
[0009]
  In the figure, the width W indicates the ground contact width.
[0010]
  In this pneumatic tire, in order to improve on-road running performance, the negative rate was set to 45% or less to secure the contact surface and the block to increase the rigidity to maintain the performance. .
[0011]
  The noise was kept by shifting the phase of each block.
[0012]
  When the tread portion of the tread 100 is divided into a central zone on the tire equatorial plane CL side of the circumferential groove 102 and both side zones located on both sides thereof, the pitch number ratio of the blocks in the central zone and both side zones is 1. : 1 was set.
[0013]
[Problems to be solved by the invention]
  By the way, in recent years, as vehicles become increasingly high power, it has become necessary to achieve both on-road and off-road performance at a higher level.
[0014]
  Usually, in order to ensure off-road and snow performance, a large number of vertical and horizontal edge components (increased sipes and the like) are arranged in the tread.
[0015]
  However, increasing the edge component in the block causes a decrease in block rigidity, leading to a deterioration in on-road performance.
[0016]
  For this reason, in general, a large block is set in order to prevent a decrease in rigidity. However, if the blocks on both sides of the tread are enlarged, there is a problem that the pattern noise is remarkably deteriorated.
[0017]
  An object of the present invention is to provide a pneumatic tire capable of improving on-road performance and pattern noise and achieving both off-road and on-snow performance in consideration of the above facts.
[0018]
[Means for Solving the Problems]
  According to the first aspect of the present invention, in the region of 10 to 40% of the ground contact width from the one tire width direction ground end of the tread to the tire equatorial plane side and from the other tire width direction ground end of the tread to the tire equatorial plane side. A circumferential groove extending along the tire circumferential direction is provided in a region of 10 to 40% of the ground contact width, and a central region is formed between the pair of circumferential grooves, and both outer sides of the pair of circumferential grooves are disposed in the tire width direction. When it is defined as a zone, the central zone and the both side zones are pneumatic tires in which at least one block row is substantially partitioned by a plurality of lateral grooves extending in the tire axial direction,The central area includes three block rows, a center block row and second block rows provided on both sides of the center block row in the tire width direction,The blocks formed in the central area have a tire circumferential dimension larger than the blocks formed in the both side areas, and the block number ratio of the block lines in the central area and the block lines in the both side areas is from 5: 9 to Set within the range of 5: 6The center block row block has an end portion that is narrower than the center side in the tire width direction on the outer side in the tire width direction, and the end portion is a tire of the block in the second block row as seen from the tire circumferential direction. It overlaps with the end side on the inner side in the width directionIt is characterized by that.
[0019]
  Next, the operation of the pneumatic tire according to claim 1 will be described.
[0020]
  In the pneumatic tire according to claim 1,
(1) Since the pair of circumferential grooves are provided in the tread, it is possible to ensure hydroplaning performance in wet conditions, side slip performance on snow, straight running stability, and the like.
(2) By dividing the tread into at least three areas in the central area and the both-side areas, the phase of the block (in the tire circumferential direction) aimed at improving pattern noise can be freely performed on both sides of the circumferential groove. .
(3) Since each section is divided by a lateral groove to form a plurality of blocks, basic performance (running on rough roads, running on ice and snow, etc.) as a four-wheel drive tire can be ensured.
(4) Since the block in the central area is set longer in the tire circumferential direction than the blocks in the both-side areas, the rigidity of the block central area necessary for the on-road (dry and wet) road surface can be ensured. Usually, in order to ensure the performance on snow, a large number of sipes are arranged in the central area of the block, and the rigidity in the circumferential direction is lowered and the on-road performance is deteriorated, but this can be suppressed and prevented.
(5) By setting the ratio of the number of blocks between the central zone and both side zones to 5: 9 to 5: 6, it is possible to increase the circumferential dimension of the blocks in the central zone and improve the on-road running performance. it can. In addition, the blocks in the two side areas can be set to have circumferential dimensions that are equal to or less than the conventional one, leading to an improvement in pitch noise. It is also effective for ride comfort and uneven wear.
[0021]
  In passenger car tires, the ratio of the number of blocks between the central zone and both side zones may be set to 1: 2, but the difference in block rigidity between the central zone blocks and the blocks on both side zones becomes too large, resulting in heavy vehicle weight. In an off-road four-wheel drive vehicle, there is a concern that uneven wear such as falling wear may occur, which is not desirable.
[0022]
  In addition, if a circumferential groove is provided in the region of less than 10% of the contact width from the tread tire width direction contact edge to the tire equator side, the width of the land portion on the shoulder side becomes too narrow, and the rigidity of the land portion on the shoulder side is reduced. Problems such as lack of.
[0023]
  On the other hand, if a circumferential groove is provided in a region exceeding 40% of the contact width from the tread tire width direction contact edge to the tire equatorial plane side, the width of the land portion on the tire equatorial plane side becomes too narrow, and the tire equatorial plane side Problems such as insufficient rigidity of the land portion arise.
[0024]
  According to a second aspect of the present invention, in the pneumatic tire according to the first aspect, a block number ratio between the block row in the central area and the block row in the both side areas is set to 2: 3. It is said.
[0025]
  Next, the operation of the pneumatic tire according to claim 2 will be described.
[0026]
  In the pneumatic tire according to claim 2, since the block number ratio of the block row in the central area and the block row in the both side areas is set to 2: 3, it is particularly effective for pitch noise, riding comfort, and uneven wear. .
[0027]
  According to a third aspect of the present invention, in the pneumatic tire according to the first or second aspect, the lateral groove of the central region and the lateral groove of the both side regions are provided with a phase difference in the tire circumferential direction, and the both side regions The transverse groove is characterized in that an angle with respect to the tire circumferential direction is set larger than that of the transverse groove in the central area.
[0028]
  Next, the operation of the pneumatic tire according to claim 3 will be described.
[0029]
  Since the lateral grooves in the central area and the lateral grooves in both side areas are provided with a phase difference in the tire circumferential direction, the pattern noise property can be improved (the frequency distribution does not have a large peak at a specific rotational speed).
[0030]
  In addition, since there is a difference in the number of blocks in the tire circumferential direction between the central area and the both side areas, the effect of phase shifting is further increased.
[0031]
  Further, in the case of a tire having a block pattern, there is a problem that uneven wear is likely to occur on the shoulder side block. However, in the pneumatic tire according to claim 3, the angle of the lateral grooves in the both side sections with respect to the circumferential direction of the tire Since the angle is set to be larger than the angle with respect to the tire circumferential direction, the rigidity of the block end (acute angle side portion) of the block formed in both side areas is ensured, and the deterioration of uneven wear is prevented.
[0032]
  The invention according to claim 4 is the pneumatic tire according to any one of claims 1 to 3,Second block rowThe block is partitioned by the circumferential groove and a lateral groove having a large angle with respect to the tire circumferential direction and a small lateral groove, and has a point-symmetrical shape with respect to one point on the tire equatorial plane, and of the sides facing each other. The shape is a curved shape that is convex toward the tire equatorial plane side.
[0033]
  Next, the operation of the pneumatic tire according to claim 4 will be described.
[0034]
  When the central area is made up of three blocks, the blocks can be arranged on the tire equatorial plane, and the on-road running performance (on-road feeling, rigidity) is improved.
[0035]
  Further, since the lateral grooves increase in the central area, the traction and braking performance on snow can be improved.
[0036]
  Also, on both sides of the tire width directionSecond block rowSince the blocks are symmetrical with respect to one point on the tire equatorial plane, restrictions on the tire mounting direction can be eliminated, for example, tire rotation can be easily performed to prevent uneven wear. Become.
[0037]
  Furthermore, since the blocks in the block row on both sides in the tire width direction are partitioned by the circumferential grooves, the lateral grooves having a large angle with respect to the tire circumferential direction, and the small lateral grooves, the shape thereof is substantially a triangle.
[0038]
  When comparing with the same length in the circumferential direction, if the shape of each side is a straight line, the triangular block has a smaller volume than the quadrangular block, and there is a concern that the block rigidity may be reduced.
[0039]
  However, in the pneumatic tire according to claim 4, since the shape of the mutually opposing sides of the block is a curved shape that protrudes toward the tire equatorial plane, the block volume is secured and the block rigidity is secured. be able to.
[0040]
  According to a fifth aspect of the present invention, in the pneumatic tire according to the fourth aspect, the three block rows provided in the central area have a phase difference in the tire circumferential direction between adjacent blocks in the tire width direction. It is characterized by being.
[0041]
  Next, the operation of the pneumatic tire according to claim 5 will be described.
[0042]
  In the case where the central area is a three-row block row, it is more effective for pitch noise if a phase difference is provided in the tire circumferential direction between blocks adjacent in the tire width direction in the three rows of blocks.
[0043]
  According to a sixth aspect of the present invention, in the pneumatic tire according to any one of the first to fifth aspects, the block formed in the central area is a sub-width that is narrower than the lateral groove of the central area. It is characterized by being divided into at least three or more sub-blocks by the groove.
[0044]
  Next, the operation of the pneumatic tire according to claim 6 will be described.
[0045]
  The block in the central area is divided into at least three or more sub-blocks by sub-grooves that are narrower than the lateral grooves in the central area, thereby reducing the number of blocks and increasing the rigidity of the central area. Rigidity can be optimized and on-road performance and off-road performance can be balanced.
[0046]
  A seventh aspect of the present invention is the pneumatic tire according to any one of the first to sixth aspects, wherein the pair of circumferential grooves are linear grooves extending in parallel to the tire circumferential direction. The groove width is different within the circumferential pitch length of at least one of the blocks adjacent to the circumferential groove.
[0047]
  Next, the operation of the pneumatic tire according to claim 7 will be described.
[0048]
  In the pneumatic tire according to the seventh aspect, since the pair of circumferential grooves are straight grooves extending in parallel to the tire circumferential direction, it is advantageous for hydroplaning as compared to the zigzag groove.
[0049]
  Here, if the groove width of the linear groove is varied within the circumferential pitch length of at least one of the blocks adjacent to the circumferential groove, the tire axial edge component increases, and on the snow, Off-road performance can be improved.
[0050]
  In addition, the groove width of the straight groove may be abruptly changed between the narrow part and the wide part, for example, a step (provided with an edge extending in the tire axial direction) rather than smoothly changing. preferable.
[0051]
DETAILED DESCRIPTION OF THE INVENTION
  Hereinafter, an example of an embodiment of the present invention will be described in detail with reference to the drawings.
[0052]
  As shown in FIG. 1, the tread 12 of the pneumatic tire 10 of the present embodiment is provided with a pair of circumferential grooves 14 on both sides of the tire equatorial plane CL.
[0053]
  The circumferential groove 14 extends linearly in the tire circumferential direction and is provided in parallel to the tire circumferential direction.
[0054]
  Here, in the present embodiment, hereinafter, the central region is between the circumferential groove 14L and the circumferential groove 14R of the tread 12, the left region is the outer side in the tire width direction of the circumferential groove 14L, and the tire width direction of the circumferential groove 14R. The outer side is called the right side area, and the left side area and the right side area are collectively called the both side areas.
[0055]
  In addition, the code | symbol W in a figure has shown the contact width. Here, the contact width is based on the maximum load capacity in the applicable size / ply rating and the corresponding air pressure (maximum air pressure) in accordance with the 2000 JATMA YEAR BOOK. It is the maximum width in the tire width direction of the portion that contacts the road surface. When the TRA standard or ETRTO standard is applied in the place of use or manufacturing, each standard is followed.
(Both sides area)
  A plurality of lateral grooves 16L extending from the circumferential groove 14L to the outer side in the tire width direction and inclined at a relatively large angle (upward to the right in the present embodiment) along the tire circumferential direction are provided in the left section 12L. As a result, a large number of shoulder blocks 18L are defined.
[0056]
  A sub-groove 20L and a sipe 22L are formed in the shoulder block 18L. The sub-groove 20L is narrower than the adjacent lateral groove 16L (even if the shoulder block 18L is grounded and compressed), and has a groove width that can maintain drainage. It extends outward in the width direction. The sub-groove 20L terminates in the shoulder block 18L.
[0057]
  On the other hand, a lateral groove 16R that extends outward in the tire width direction from the circumferential groove 14R and inclines at a relatively large angle with respect to the tire circumferential direction (upward to the right in the present embodiment) is provided along the tire circumferential direction. By providing a plurality of shoulder blocks 18R, a large number of shoulder blocks 18R are defined. The shoulder block 18R is formed with a sub-groove 20R and a sipe 22R. The sub-groove 20R is narrower than the adjacent lateral groove 16R (even when the shoulder block 18R is grounded and compressed, it has a groove width and can maintain drainage) and extends from the circumferential groove 14R to the tire. It extends outward in the width direction. The sub-groove 20R terminates in the shoulder block.
(Central area)
  Next, in the central area, the lower right lateral groove 24L extending from the circumferential groove 14R to the tire equatorial plane CL side, and disposed between the lateral groove 24L and the lateral groove 24L, is also arranged from the circumferential groove 14R to the tire equatorial plane CL. It is disposed between the laterally-lowering lateral groove 26L extending substantially linearly to the side and connected to the lateral groove 24L, the laterally-growing lateral groove 24R extending from the circumferential groove 14R toward the tire equatorial plane CL, and between the lateral groove 24R and the lateral groove 24R. A plurality of leftwardly rising lateral grooves 26R that extend substantially linearly from the circumferential groove 14R toward the tire equatorial plane CL and connect to the lateral grooves 24R, and a rightwardly upward lateral groove 28 that connects the lateral grooves 24L and 24R are provided. .
[0058]
  The central section has a plurality of second blocks 30L on the circumferential groove 14L side and a plurality of second blocks 30R on the circumferential groove 14R side due to these lateral grooves 24L, lateral grooves 24R, lateral grooves 26L, lateral grooves 26R and lateral grooves 28. A plurality of center blocks 32 are defined on the tire equatorial plane CL.
[0059]
  The lateral groove 24L and the lateral groove 24R are curved in a substantially arc shape in which the angle on the tire circumferential direction gradually increases from the tire equatorial plane CL side toward the outer side in the tire width direction, and the tire equatorial plane CL side is convex. 24R is arranged with a phase difference in the tire circumferential direction. As a result, the second block 30L and the second block 30R have a point-symmetric shape with one point on the tire equatorial plane CL as a point of symmetry.
[0060]
  The second blocks 30L and 30R of the present embodiment have a substantially fan shape.
[0061]
  The second block 30L has a sub-groove 34L and a sub-groove 36L that are narrower than the adjacent lateral grooves 24L (the width that allows the drainage to be maintained even if the second block 30L is compressed by grounding). Sub-grooves 38L are formed.
[0062]
  The sub-groove 34L extends from the circumferential groove 14L toward the tire equatorial plane CL, and is inclined in the same direction as the adjacent lateral grooves 24L and 26L. The sub-groove 34L terminates in the block.
[0063]
  Further, the sub-groove 36L and the sub-groove 38L are inclined in the opposite direction to the sub-groove 34L and connect the sub-groove 20L and the lateral groove 24L. The second groove 34L, the sub-groove 36L, and the sub-groove 38L are connected to the second block. 30L is divided into three sub-blocks.
[0064]
  Note that sipes 40L are formed in the respective sub-blocks of the second block 30L.
[0065]
  The second block 30R has sub-grooves 34R and 36R that are narrower than the adjacent lateral grooves 24R (the width that allows the drainage to be maintained even if the second block 30R is grounded and compressed). A sub-groove 38R is formed.
[0066]
  The sub-groove 34R extends from the circumferential groove 14R toward the tire equatorial plane CL, and is inclined in the same direction as the adjacent lateral grooves 24R and 26R. The sub-groove 34R terminates in the block.
[0067]
  Further, the sub-groove 36R and the sub-groove 38R are inclined in the opposite direction to the sub-groove 34R and connect the sub-groove 20R and the lateral groove 24R, and the second block is formed by the sub-groove 34R, the sub-groove 36R, and the sub-groove 38R. 30R is divided into three sub-blocks.
[0068]
  A sipe 40R is formed in each sub-block of the second block 30R.
[0069]
  The center block 32 is partitioned by two lateral grooves 24L, two lateral grooves 24R, two lateral grooves 28, a lateral groove 26L, and a lateral groove 26R. The part to be formed is formed narrow toward the outside in the tire width direction.
[0070]
  The center block 32 is inclined in the same direction as the adjacent lateral groove 28 and has a narrow width (a width that has a groove width and can maintain drainage even when the center block 32 is grounded and compressed). The sub-groove 41 is divided into three in the tire circumferential direction by forming a sub-groove 42 that is inclined in the same direction as the adjacent lateral groove 28 on both sides of the sub-groove 41 in the circumferential direction and is further narrowed. . Further, a sipe 44 that is inclined in the direction opposite to the sub-groove 41 is formed in the center portion of the center block 32.
[0071]
  When viewed along the tire circumferential direction, the vicinity of the end of the second block 30L on the tire equatorial plane CL side, the vicinity of the narrow end of the center block 32 on the left in the tire width direction, and the tire equatorial plane of the second block 30R The vicinity of the end on the CL side and the vicinity of the narrow end on the right side of the center block 32 in the tire width direction overlap in the tire width direction.
[0072]
  The second block 30L and the second block 30R pass through the intermediate portion of the overlap portion in the tire width direction from the chamfering start line 46 provided in parallel to the tire equatorial plane CL to the portion on the tire equatorial plane CL side. A chamfer 48 as shown in FIG. 2 is formed.
[0073]
  In this embodiment, the chamfer 48 is inclined at a constant angle θ1 with respect to the normal line standing on the tread surface so as to descend from the chamfer start line 46 toward the tire equatorial plane CL.
[0074]
  On the other hand, in the center block 32, the distance in the tire width direction from the tire equatorial plane CL is positioned at the outer side in the tire width direction from the chamfering start line 50 set at the same distance as the chamfering start line 46 described above, as shown in FIG. A chamfer 52 is formed.
[0075]
  In this embodiment, the chamfer 52 is lowered from the chamfer start line 50 toward the outer side in the tire width direction. In this embodiment, the chamfer 52 is a constant angle θ2 (in this embodiment, θ2≈θ1, but θ2 = θ1 may be used). It is inclined at.
[0076]
  In this embodiment, the pitch number ratio between the blocks in the central area and the blocks in the both-side areas is 2: 3, but it may be set in the range of 5: 9 to 5: 6.
[0077]
  Further, the circumferential groove 14L of the present embodiment has a wide portion and a narrow portion within one circumferential pitch of the shoulder block 18L, and a step portion (tire width) at the boundary portion between the wide portion and the narrow portion. Edge component extending in the direction).
[0078]
  Similarly, the circumferential groove 14R of the present embodiment has a wide portion and a narrow portion within one circumferential pitch of the shoulder block 18R, and a step portion (tire) at the boundary portion between the wide portion and the narrow portion. Edge component extending in the width direction).
[0079]
  In this embodiment, the circumferential groove 14L (width direction center line position) is provided in a region of 21% of the contact width W from the tire width direction contact end on the left side of the tread 12 to the tire equatorial plane CL. The circumferential groove 14R (width direction center line position) is provided in a region of 21% of the contact width W from the tire width direction contact end on the right side of the tread 12 to the tire equatorial plane CL. The positions in the tire width direction of the grooves 14L and the circumferential grooves R are not limited to the above positions.
[0080]
  However, the circumferential groove 14L is provided in a region of 10 to 40% of the contact width W from the tire width direction contact end on the left side of the tread 12 to the tire equatorial plane CL, and the circumferential groove 14R is the drawing of the tread 12. It is preferable to provide in the region of 10 to 40% of the contact width W from the right tire width direction contact end to the tire equatorial plane CL side.
[0081]
  For example, if the circumferential grooves 14L and 14R are provided in regions of less than 10% of the ground contact width W from the tire width direction ground end of the tread 12 to the tire equatorial plane CL side, the width of the shoulder block 18L becomes narrow. The block rigidity of the shoulder block 18L is insufficient. On the other hand, if the circumferential grooves 14L, 14R are provided in a region exceeding 40% of the ground contact width W from the tire width direction ground end of the tread 12 to the tire equatorial plane CL side, the center block 32 becomes too narrow. The rigidity of the block 32 is insufficient.
(Function)
  Next, the effect | action of the pneumatic tire 10 of this embodiment is demonstrated.
[0082]
  (1) Since the circumferential groove 14L and the circumferential groove 14R are provided in the tread 12, it is possible to ensure hydroplaning performance in wet conditions, side slip performance on snow, straight running stability, and the like.
(2) Since the tread 12 is divided into three areas, the central area and the both-side areas, and the phase of the block is shifted between the blocks in the central area and the blocks in the both-side areas, the pattern noise can be improved.
(3) Since each block is formed with a plurality of blocks, the basic performance (running on rough roads, running on ice and snow, etc.) as a four-wheel drive tire can be ensured.
(4) The block number ratio between the central area and the two-side areas is set to 2: 3, the tire circumferential direction lengths of the center block 32 and the second blocks 30L, 30R in the central area, and the tire circumferences of the shoulder blocks 18L, 18R in the both-side areas. Since the length is set longer than the direction length, the rigidity of the block central area required on the on-road (dry and wet) road surface can be ensured despite the provision of the sipes 40 and 44.
(5) Since the ratio of the number of blocks in the central area and the both-side areas is set to 2: 3, the shoulder blocks 18L and 18R in the both-side areas can be set to circumferential dimensions that are equal to or less than the conventional size, and pitch noise. It is also effective for riding comfort and uneven wear.
(6) Since the block in the central area and the block in the both-side areas are provided with a phase difference in the tire circumferential direction, the pattern noise can be improved. In addition, since there is a difference in the number of blocks in the tire circumferential direction between the central area and the both side areas, the effect of phase shifting is further increased.
(7) Since the angle of the lateral grooves 16L, 16R with respect to the tire circumferential direction of the both side sections is set larger than the angle with respect to the tire circumferential direction of the lateral grooves 24L, 24R and the lateral grooves 26L, 26R of the central section, the shoulder block formed in the both side sections The rigidity of the block ends (acute angle side portions) of 18L and 18R is ensured, and the deterioration of uneven wear is prevented.
(8) Since the central area is made up of three block rows and the center blocks 32 are arranged on the tire equatorial plane, on-road running performance (on-road feeling, rigidity) is improved.
[0083]
  Further, since there are a large number of lateral grooves (24L, 24R, 26L, 26R, 28) in the central area, the traction and braking performance on snow can be improved.
(9) The center block 32 is point symmetric with respect to the point on the tire equator plane CL, the second block 30L and the second block 30R are point symmetric with respect to each other on the tire equator plane CL, Since the shoulder block 18L and the shoulder block 18R are point-symmetrical with respect to each other on one point on the tire equatorial plane CL, the restriction on the tire mounting direction can be eliminated. This makes it easier to perform tire rotation.
(10) Both the second block 30L and the second block 30R are substantially triangular, but the shape of the sides facing each other is a substantially arc shape that protrudes toward the tire equatorial plane CL, so the volume and the second block 30L The volume of each block 30R is secured, and the block rigidity of the second block 30L and the block rigidity of the second block 30R can be secured.
(11) Since the center block 32 in the central area, the left second block 30L, and the right second block 30R are provided with a phase difference in the tire circumferential direction between adjacent blocks, it is more effective against pitch noise. It becomes.
(12) Since the center block 32, the second block 30L, and the second block 30R formed in the central area are each divided into three sub-blocks, the rigidity is increased by reducing the number of blocks (compared to the both-side areas). The block stiffness in the central area can be optimized and the on-road performance and off-road performance can be balanced.
(13) Since the pair of circumferential grooves 14 are constituted by linear grooves extending in parallel to the tire circumferential direction, the drainage is superior to the zigzag groove, and the hydroplaning property is advantageous.
(14) Steps are provided by varying the groove width of the circumferential groove 14L within the circumferential pitch length of the shoulder block 18L, and similarly, the groove width of the circumferential groove 14R is within the circumferential pitch length of the shoulder block 18R. In order to increase off-road performance on snow, the edge component in the axial direction of the tire increases.Can be increased.
[0084]
  In the present invention, the number of circumferential grooves provided in the tread 12 is not limited to four as in the above embodiment, but it is preferable to provide a block row on the tire equatorial plane CL as described above.
[0085]
【The invention's effect】
  As described above, since the pneumatic tire according to claim 1 has the above-described configuration, it is possible to improve on-road performance and pattern noise and achieve both off-road performance and on-snow performance.
[0086]
  Since the pneumatic tire according to claim 2 has the above configuration, it is particularly effective for pitch noise, riding comfort, and uneven wear.
[0087]
  Since the pneumatic tire according to claim 3 has the above configuration, the pattern noise property can be improved, and the effect of phase shifting can be further increased. Further, it is possible to prevent the uneven wear of the blocks formed in the both side areas from being lowered.
[0088]
  Since the pneumatic tire according to claim 4 has the above-described configuration, it is possible to improve on-road running performance (on-road feeling, rigidity). Since the lateral grooves increase in the central area, the traction and braking performance on snow can be improved. Tire rotation for preventing uneven wear is facilitated. Further, in the block rows on both sides in the tire width direction, the block volume can be secured and the block rigidity can be secured.
[0089]
  Since the pneumatic tire according to claim 5 has the above-described configuration, it is further effective against pitch noise.
[0090]
  Since the pneumatic tire according to claim 6 is configured as described above, it is possible to balance on-road performance and off-road performance.
[0091]
  Since the pneumatic tire according to claim 7 has the above-described configuration, it is advantageous for hydroplaning as compared to the zigzag groove. Further, since the edge component in the tire axial direction increases, off-road performance can be enhanced on snow.
[Brief description of the drawings]
FIG. 1 is a plan view of a tread of a pneumatic tire according to an embodiment of the present invention.
FIG. 2 is a cross-sectional view of the second block along the tire rotation axis.
FIG. 3 is a cross-sectional view of the center block along the tire rotation axis.
[Fig. 4]It is a top view of the tread of the conventional pneumatic tire.
[Explanation of symbols]
        10 Pneumatic tire
        12 tread
        14L circumferential groove
        14R circumferential groove
        18L shoulder block
        18R shoulder block
        24L lateral groove
        24R lateral groove
        28 Horizontal groove
        30L second block
        30R second lock
        32 Center block
        34L minor groove
        34R minor groove
        36L minor groove
        36R minor groove
        38L minor groove
        38R minor groove
        40 minor groove
        42 minor groove

Claims (7)

10 to 40% of the contact width from one tire width direction contact edge of the tread to the tire equator plane side and 10 to 40% of the contact width from the other tire width direction contact edge of the tread to the tire equator surface side Each of which includes a circumferential groove extending along the tire circumferential direction, the central area between the pair of circumferential grooves, and the outer side in the tire width direction of the pair of circumferential grooves as both side areas. And the both side sections are pneumatic tires in which at least one block row is substantially partitioned by a plurality of lateral grooves extending in the tire axial direction,
The central area includes three block rows, a center block row and second block rows provided on both sides of the center block row in the tire width direction,
The block formed in the central area has a tire circumferential dimension larger than the blocks formed in the both side areas,
The block number ratio of the block row of the central zone and the block row of the both side zones is set within a range of 5: 9 to 5: 6 ,
The block of the center block row has an end portion narrower than the center side in the tire width direction on the outer side in the tire width direction, and when viewed from the tire circumferential direction, the end portion is the tire width direction of the block of the second block row A pneumatic tire characterized by overlapping with the inner end side .   2. The pneumatic tire according to claim 1, wherein a block number ratio of the block row in the central area and the block row in the both-side areas is set to 2: 3. The lateral groove in the central area and the lateral groove in the both side areas are provided with a phase difference in the tire circumferential direction,
3. The pneumatic tire according to claim 1, wherein the lateral grooves in the both side areas are set to have a larger angle with respect to the tire circumferential direction than the lateral grooves in the central area. The blocks of the second block row are partitioned by the circumferential groove, a lateral groove having a large angle with respect to the tire circumferential direction, and a small lateral groove, and are point-symmetric with respect to each other on one point on the tire equatorial plane. The pneumatic tire according to any one of claims 1 to 3, wherein the opposing sides have a curved shape that protrudes toward the tire equatorial plane.   5. The pneumatic tire according to claim 4, wherein the three block rows provided in the central area are provided with a phase difference in the tire circumferential direction between blocks adjacent in the tire width direction.   The block formed in the central area is divided into at least three or more sub-blocks by sub-grooves narrower than the lateral grooves of the central area. The pneumatic tire according to claim 1.   The pair of circumferential grooves are linear grooves extending in parallel to the tire circumferential direction, and the groove width is the circumferential pitch length of at least one of the blocks adjacent to the circumferential groove. The pneumatic tire according to any one of claims 1 to 6, wherein the pneumatic tire is different.