JP4390879B2 - Pneumatic tire - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
  The present invention relates to a pneumatic tire that exhibits good ice and snow performance.
[0002]
[Prior art]
  2. Description of the Related Art Conventionally, there is a pneumatic tire in which a plurality of blocks partitioned by main grooves formed in the tire circumferential direction and lug grooves formed in the tire width direction are provided on the tread surface. Thus, by providing the block on the tread surface, the pneumatic tire ensures good braking / driving force, steering stability, and the like.
[0003]
  In addition, sipe is provided on the block to increase the edge length and increase the gripping force, thereby improving the snow and snow performance and the wet performance.
[0004]
Further, on the lower side of the tread surface of the pneumatic tire formed in this way, a reinforcing layer in which a number of steel cords are arranged in parallel is laminated in order to increase the rigidity of the tread.
[0005]
[Problems to be solved by the invention]
  In the pneumatic tire configured as described above, the tread side of each block is divided into a plurality of small blocks by sipes. Each small block tends to collapse due to frictional force with the ground contact surface when the tire rotates. If the fall is large, the ground contact area on the tread surface is reduced, and there is a possibility that the ice / snow performance is lowered.
[0006]
  However, since the small block is compressed in the height direction (the direction from the tread surface toward the tire axis) by the contact pressure from the tread surface and swells in the lateral direction (direction perpendicular to the height direction), the small block adjacent to the sipe Abutting on the block, the collapse is suppressed to some extent.
[0007]
  However, in a sipe that is formed straight in the sipe depth direction, deformation of a small block due to contact pressure alone cannot contact an adjacent small block with sufficient force, and there is little suppression of falling down. It was hard to say that it was enough.
[0008]
  A plurality of steel cords arranged in each reinforcing layer are arranged in parallel at a predetermined angle with respect to the tire circumferential direction. Therefore, when a pneumatic tire is actually mounted on a vehicle, the tire deformed by the contact pressure will be restored to its original shape due to the inclination of the steel cord disposed on the reinforcing layer on the tread surface side with respect to the tire circumferential direction. (Self Alignment Torque, hereinafter referred to as SAT) occurs.
[0009]
  In view of such facts, an object of the present invention is to provide a pneumatic tire that suppresses the falling of a sipe-containing block to exhibit good ice and snow performance and suppresses SAT.
[0010]
[Means for Solving the Problems]
[0011]
[0012]
[0013]
[0014]
[0015]
[0016]
[0017]
[0018]
  In the invention according to claim 1, a plurality of reinforcing layers in which cords inclined at a predetermined angle with respect to the tire circumferential direction are arranged in parallel, a tread provided above the laminated reinforcing layers, and the tread surface In, the main groove formed in the tire circumferential direction and the lug groove formed in the direction intersecting the main grooveBlocked block landWhen,A plurality of sipes traversing the block land,A pneumatic tire comprising:The sipe has a zigzag shape that alternately protrudes on both sides of the virtual center plane from the tread of the block-shaped land portion toward the sipe bottom, or a zigzag shape that alternately protrudes on both sides of the virtual center plane in the sipe longitudinal direction, The zigzag virtual center plane from the surface portion exposed on the tread surface of the block-shaped land portion toward the sipe bottomIt is characterized by being twisted.
[0019]
  Claim 1The operation of the invention will be described.
[0020]
  Since the sipe has a structure twisted from the surface part toward the bottom part, the block-like land part is compressed in the height direction by the ground pressure and swells in the lateral direction, so that the small blocks divided by the sipe Abut. Further, since the sipe (virtual center plane) is twisted, the small blocks come into contact with each other not only with a force acting in the tire circumferential direction (tire rotation direction) but also with a force acting in another direction. Further, since the small blocks rotate by the contact pressure, adjacent small blocks are brought into contact with each other with a strong force.
[0021]
  In this manner, the sipe is formed by twisting, so that the small blocks are brought into contact with each other with a strong force and the collapse is reliably suppressed. As a result, the ground contact area on the tread surface of the small block is increased, and the ice / snow performance is improved.
[0022]
  In particular,Sipes are not only twisted, but also protrude alternately on both sides of the virtual center planeIt has irregularities across the virtual center planeZigzag shapeTherefore, only by deforming the block-like land portion by the contact pressure, the small blocks are brought into contact with each other more strongly and the contact area is increased. Therefore, the fall of the small block is further suppressed, the contact area on the tread surface is increased, and the ice / snow performance is further improved.
[0023]
  In addition, when the contact pressure acts on the tread of the block-shaped land, the height direction of the block-shaped land is compressed, guided by the sipe, and each small block is deformed in a direction in which the sipe (virtual center plane) is further twisted. To do. Due to this deformation, a SAT (rotational moment to be restored to the original shape) in the direction opposite to the twisting direction is generated in each small block.
[0024]
  Therefore, by forming a block-shaped land portion with a sipe twisted in an appropriate direction on the tread surface, SAT generated by the inclination of the cord constituting the outermost reinforcing layer with respect to the tire circumferential direction is reduced. That is, the SAT generated by the block land can suppress the SAT caused by the code.
[0025]
  Claim 2In the invention ofClaim 1In the invention, the virtual center plane has a shape twisted about a first torsion center axis extending in a tire radial direction in the block-shaped land portion, and the first torsion center axis The position P1 is in a range satisfying the following relational expression between one end face and the other end face of the block-shaped land portion in the tire width direction.
[0026]
        0.2W ≦ P1 ≦ 0.8W
  Here, P1 is the position of the first twisting central axis, and W is the distance from one end surface of the block-shaped land portion to the other end surface in the tire width direction.
[0027]
  Claim 2The operation of the invention will be described.
[0028]
  In this way, the sipe is formed in a shape in which the imaginary center plane is twisted about the first twist center axis extending in the tire radial direction. In this case, the position P1 of the first torsional central axis is within the range of 0.2W ≦ P1 ≦ 0.8W with respect to the width W of the block land portion, so that the position P1 is outside the range. The rigidity is higher than that of a small block divided by a certain sipe (see FIG. 24). Therefore, the fall of the small block is further suppressed, the contact area on the tread surface is increased, and the ice / snow performance is further improved.
[0029]
  Claim 3In the invention ofClaim 1 or claim 2In the invention, the virtual center plane has a shape twisted around a second torsion center axis extending substantially in the tire width direction in the block-shaped land portion, and the second torsion center axis Is located within a range satisfying the following relational expression between the tread surface and the sipe bottom in the tire radial direction.
[0030]
        0.2F ≦ P2 ≦ 0.6F
  Here, P2 is the position of the second twisting central axis, and F is the distance from the tread surface to the sipe bottom in the tire radial direction.
[0031]
  Claim 3The operation of the invention will be described.
[0032]
  In this way, the sipe is formed in a shape twisted about the second torsional central axis in which the virtual center plane extends substantially in the tire width direction. In this case, the position P2 of the second torsional central axis is within the range of 0.2F ≦ P2 ≦ 0.6F with respect to the sipe depth F, so that the position P2 is out of the range. The rigidity is higher than that of the divided small blocks (see FIG. 25). Therefore, the fall of the small block is further suppressed, the contact area on the tread surface is increased, and the ice / snow performance is further improved.
[0033]
  Claim 4In the invention, a plurality of reinforcing layers in which cords inclined at a predetermined angle with respect to the tire circumferential direction are arranged in parallel, a tread provided on the laminated reinforcing layer, and a tire circumferential direction on the tread surface And a sipe-containing block-shaped land portion defined by a lug groove formed in a direction intersecting with the main groove, wherein the sipe is the main groove. And a closed loop shape not communicating with the lug groove, including a surface portion exposed on the tread surface of the block-shaped land portion and a bottom portion formed on the sipe bottom, and twisted from the surface portion toward the bottom portion It is characterized by being.
[0034]
  Claim 4The operation of the invention will be described.
[0035]
  Since the sipe has a structure twisted from the surface part toward the bottom part, the block-like land part is compressed in the height direction by the ground pressure and swells in the lateral direction, so that the small blocks divided by the sipe Abut. Moreover, since the sipe formed in the closed loop shape is twisted, the small blocks divided by the sipe not only by the force acting in the tire circumferential direction (tire rotation direction) but also by the force acting from other directions Abut. Further, since the small blocks rotate by the contact pressure, adjacent small blocks are brought into contact with each other with a strong force.
[0036]
  In this manner, the sipe is formed by twisting, so that the small blocks are brought into contact with each other with a strong force and the collapse is reliably suppressed. As a result, the ground contact area on the tread surface of the small block increases, improving the snow and snow performance.
[0037]
  Further, when the contact pressure acts on the tread of the block-shaped land portion, the height direction of the block-shaped land portion is compressed, and the small block is deformed in a direction in which the sipe is further twisted by being guided by the sipe. By this deformation, SAT (rotational moment to be restored to the original shape) in the direction opposite to the twisting direction is generated in the small block.
[0038]
  Therefore, by forming a block-shaped land portion with a sipe twisted in an appropriate direction on the tread surface, SAT generated by the inclination of the cord constituting the outermost reinforcing layer with respect to the tire circumferential direction is reduced. That is, the SAT generated by the block land can suppress the SAT caused by the code.
[0039]
  Claim 5The invention ofClaims 1-4In the invention according to any one of the above, the block-shaped land portion is twisted from the tread surface toward the base portion.
[0040]
  Claim 5The operation of the invention will be described.
[0041]
  Since not only the sipes but also the block-shaped land portions are twisted, the force in the rotational direction acting on the block-shaped land portions is increased by the ground pressure. As a result, the force for bringing adjacent small blocks into contact with each other in the block-shaped land portion or the SAT (rotational moment to be restored to the original shape) of the small blocks is further increased, and the handling stability of the pneumatic tire is further increased. .
[0042]
  Claim 6The invention ofClaim 5In this invention, the twisting direction of the block land portion is the same as the twisting direction from the tread surface of the sipe toward the sipe bottom.
[0043]
  Claim 6The operation of the invention will be described.
[0044]
  Since the twist direction from the sipe tread to the bottom of the sipe is the same as the twist direction of the block land, the rotation direction of the small block generated by the sipe due to contact pressure and the twist of the block land The direction of rotation of the generated block land matches. Therefore, the SAT (rotational moment to be restored to the original shape) generated in the block land portion is further increased, and the SAT generated by the cord can be more easily suppressed. Thereby, the steering stability is further improved.
[0045]
  Claim 7The invention ofClaim 5In the invention, the twisting direction of the block-shaped land portion is a direction opposite to the twisting direction from the sipe tread surface toward the sipe bottom.
[0046]
  Claim 7The operation of the invention will be described.
[0047]
  Since the torsion direction of the block land is opposite to the torsion direction from the sipe tread to the sipe bottom, the rotation direction of the block land and the sipe Since the rotation directions of the small blocks generated by twisting are opposite, the small blocks are brought into contact with each other with a strong force. As a result, the falling of the small blocks is further suppressed, and the snow and ice performance is improved.
[0048]
DETAILED DESCRIPTION OF THE INVENTION
[Reference example]
  Before explaining the pneumatic tire of the present invention, a pneumatic tire according to a reference exampleWill be described with reference to FIGS.
[0049]
  As shown in FIG.This reference exampleThe tread 12 of the pneumatic tire 10 has a main groove 14 extending along a tire circumferential direction (arrow A direction, hereinafter referred to as A direction) and a tire width direction (arrow B direction, hereinafter referred to as B direction). A plurality of blocks 18 defined by the lug grooves 16 are formed.
[0050]
  Under the tread 12, in order to ensure the rigidity of the pneumatic tire 10, a reinforcing layer in which a steel cord 19 is inclined at a predetermined angle with respect to the A direction is laminated. In the outermost reinforcing layer closest to the surface of the tread 12, a steel cord 19 is disposed in parallel with an inclination of a predetermined angle θ1 with respect to the A direction, as shown in FIG.
[0051]
  As shown in FIG. 2, the block 18 is formed with a sipe 24 that is open to the side surfaces 20 and 22 in the B direction (both side openings).
[0052]
  The sipe 24 includes a surface portion 28 that is straight on the tread surface 26 and a bottom portion 30 that is straight on the bottom of the sipe, and when viewed from the tread surface 26, the surface portion 28 and the bottom portion 30 are X as shown in FIG. Cross on the mold.
[0053]
  Further, the sipe 24 includes a first side surface portion 32 that is straight on the side surface 20 and a second side surface portion 34 that is straight on the side surface 22, and when viewed from the side surface 20, as shown in FIG. The first side surface portion 32 and the second side surface portion 34 cross in an X shape.
[0054]
  That is, the sipe 24 passes through a point where the surface portion 28 and the bottom portion 30 intersect in a plan view from the tread surface 26 and has an angle from the surface portion 28 toward the bottom portion 30 about the rotation axis Z perpendicular to the tread surface 26. The shape is twisted by θ2.
[0055]
  In addition, the sipe 24 passes through a point where the first side surface portion 32 and the second side surface portion 34 intersect in the side view from the side surface 20, and is centered on the rotation axis Y substantially parallel to the tread surface 26. The shape is twisted by an angle θ12 from 32 toward the second side surface portion 34.
[0056]
  The block 18 is divided into small blocks 18a to 18d on the tread surface 26 side by the sipe 24 formed in this way.
[0057]
  When the pneumatic tire 10 thus formed is mounted on a vehicle and travels, the following effects can be obtained.
[0058]
  A force perpendicular to the tread 26 from the road surface acts on the tread 26 of the block 18. As a result, the block 18 is compressed in the block height direction (arrow C direction, hereinafter referred to as C direction) and swells in the horizontal direction (A, B direction), so that the small blocks facing each other across the sipe 24 come into contact with each other. At that time, since the sipe 24 is formed in a twisted shape, not only the force acting in the A direction which is the tire rotating direction by the frictional force but also the small adjacent force acting in the B direction acting during cornering, etc. The blocks come into contact.
[0059]
  Further, since the small blocks 18a to 18d are rotated clockwise in a plan view from the tread 26 by the contact pressure (see the solid line arrow in FIG. 3), the adjacent small blocks come into contact with each other.
[0060]
  That is, since the sipe 24 is formed in a twisted shape, adjacent small blocks come into strong contact with each other by forces acting from various directions.
[0061]
  As a result, the falling of the small blocks 18a to 18d is greatly suppressed, the contact area on the tread 26 of the block 18 is increased, and good ice and snow performance is ensured.
[0062]
  Further, due to the rotation of the small blocks 18a to 18d described above, a counterclockwise rotational moment (SAT) is generated in each of the small blocks 18a to 18d (see the broken line arrow in FIG. 3).
[0063]
  Therefore, the clockwise SAT (see FIG. 1 arrow) generated by the steel cord 19 arranged in parallel with the outermost reinforcing layer can be suppressed (reduced) by the counterclockwise SAT generated by each block 18. .
[0064]
  By the way, the position P1 of the rotation axis Z in a plan view from the tread 26 is 0.2W ≦ P1 ≦ 0.8W from the side surface 20 to the side surface 22 in the B direction (W is the width of the block 18 in the B direction, and so on). It is preferable to be within the range. By positioning the rotation axis Z within this range, the rigidity of the small blocks 18a to 18d increases, and the small blocks 18a to 18d can be prevented from falling. As a result, the ice / snow performance is further improved.
[0065]
  Further, the position P2 of the rotation axis Y in the side view from the side surface 20 is 0.2F ≦ P1 ≦ 0.6F (F is perpendicular to the sipe 24 (C) from the tread surface 26 toward the bottom 30 (sipe bottom) in the C direction. It is preferable to be within the range of the direction) depth, the same applies hereinafter. By positioning the rotation axis Y within this range, the rigidity of the small blocks 18a to 18d is increased, and the small blocks 18a to 18d can be prevented from falling down. As a result, the snow and ice performance is further improved.
[0066]
  In addition, the size of the block 18 in this embodiment is length L × width W × height H is 30 mm × 20 mm × 10 mm. The vertical depth F from the tread surface 26 of the sipe 24 is 8 mm. The sipe 24 is formed on the side surface 20 at a position where the distance a from the end surface in the A direction of the block 18 and the distance a between adjacent sipes is 7 mm, and the distance b to the other end surface is 9 mm. The side face 22 is formed at a position where the distance b from the end face in the A direction of the block 18 is 9 mm, the distance a between adjacent sipes, and the distance a to the other end face is 7 mm, and the both end faces are connected by a straight line. . The twist angle θ2 of the sipe 24 is 11.4 °, and the twist angle θ12 is 28.1 °.
[First Embodiment]
  Next, the present inventionFirst embodimentA pneumatic tire according to the present invention will be described with reference to FIGS.Reference exampleSince only the sipe shape is different from this pneumatic tire, only the sipe and the blade used to form the sipe will be described. In addition,Reference exampleThe same reference numerals are given to the same constituent elements as those in FIG.
[0067]
  First, the shape of the blade forming the sipe will be described with reference to FIG. The blade 40 is formed in a zigzag shape in which convex portions 42 that are triangles having a height of 0.5 K in the cross section in the D direction protrude alternately on both sides of the virtual center plane V at intervals J, and each convex portion 42 is orthogonal to the D direction. Extends in the E direction. The blade 40 formed in this way has a virtual center plane V.Reference exampleThe block is vulcanized and molded in the mold.
[0068]
  The sipe 44 of the block 18 formed by the blade 40 has a virtual center plane V of the sipe 44 in the block 18 as shown in FIG.Reference exampleIt is formed so as to be located at the same position as the sipe 24.
[0069]
  That is, when viewed from the side surface 20, the sipe 44 has a first side surface portion 46 (virtual center plane V) on the side surface 20 and a second side surface portion 48 (side virtual center) on the side surface 22 as shown in FIG. The surface V) crosses the X shape. Further, when viewed in plan from the tread 26, the virtual center plane V of the sipe 44 is formed at the position of the sipe 24 in FIG.
[0070]
  Therefore,Reference exampleIn a similar manner to the sipe 24, the virtual center plane V of the sipe 44 is twisted by an angle θ2 in a plan view from the tread 26 from the tread 26 toward the sipe bottom about the rotation axis Z perpendicular to the tread 26. (See FIG. 3).
[0071]
  Further, the virtual center plane V of the sipe 44 has a rotational axis Y that passes through a point where the virtual center plane V of the side surface 20 and the side surface 22 intersects and is substantially parallel to the tread surface 26 in a side view from the side surface 20. The shape is twisted by an angle θ12 from the side surface 20 toward the side surface 22 (see FIG. 5).
[0072]
  As shown in FIG. 5, the sipe 44 is opposite to the first protrusion 45 a that protrudes in the first direction with respect to the virtual center plane V corresponding to the protrusion 42 of the blade 40. It has the 2nd convex part 45b which protrudes in a certain 2nd direction.
[0073]
  When the pneumatic tire 10 thus formed is mounted on a vehicle and travels, the following effects can be obtained.
[0074]
  That is,Reference exampleSimilarly, since the sipe 44 is formed by being twisted by an angle θ2, adjacent small blocks come into contact with each other with a strong force due to forces from various directions acting from the tread surface 26 of the block 18.
[0075]
  Further, since the small blocks 18a to 18d are rotated clockwise in a plan view from the tread 26 by the contact pressure (see the solid line arrow in FIG. 3), the adjacent small blocks come into contact with each other.
[0076]
  In particular, since the sipe 44 has an uneven portion whose AC cross section (a cross section cut by a plane formed by the A direction and the C direction, the same applies hereinafter) is a triangular shape, the small blocks 18a to 18d are compressed in the C direction. As a result, the concave and convex surfaces of the small blocks adjacent to each other across the sipe 44 are brought into contact with each other with a strong force.
[0077]
  As a result, the falling of the small blocks 18a to 18d is further suppressed, and the snow and ice performance can be further improved.
[0078]
  Also,Reference exampleSimilarly, since the sipe 44 has a shape twisted about the rotation axis Z by an angle θ2, the small blocks 18a to 18d rotate clockwise in a plan view from the tread surface 26 by the ground pressure.
[0079]
  Due to this rotation, a counterclockwise rotational moment (SAT) is generated in each of the small blocks 18a to 18d to restore the original shape.
[0080]
  Therefore, the clockwise SAT (see FIG. 1 arrow) generated by the steel cord 19 arranged in parallel with the outermost reinforcing layer can be suppressed (reduced) by the counterclockwise SAT generated by each block 18. .
[0081]
  By the way, the position P1 of the rotation axis Z in plan view from the tread 26 isReference exampleSimilarly, it is preferable that 0.2 W ≦ P1 ≦ 0.8 W in the B direction from the side surface 20 toward the side surface 22. Further, the position P2 of the rotation axis Y in a side view from the side surface 20 is preferably in the range of 0.2F ≦ P2 ≦ 0.6F from the tread surface 26 toward the bottom 30 in the C direction. By positioning the rotary shaft Z and the rotary shaft Y within this range, the rigidity of the small blocks 18a to 18d is increased, and the small blocks 18a to 18d can be prevented from falling. As a result, the ice / snow performance is further improved.
[0082]
  The size of the block 18 in this embodiment isReference exampleSimilarly, length L × width W × height H is 30 mm × 20 mm × 10 mm. The vertical depth F from the tread surface 26 of the sipe 44 is 8 mm. Further, the sipe 44 is formed on the side surface 20 so that the distance a from the end surface in the A direction of the block 18 and the distance a between adjacent sipes are 7 mm and the distance b to the other end surface is 9 mm. The distance b from the end surface in the A direction of the block 18 on the opposite side surface 22 is 9 mm, the distance a between adjacent sipes, and the distance a to the other end surface is 7 mm. It is the shape which connects with a straight line. The twist angle θ2 of the sipe 44 is 11.4 °, and the twist angle θ12 is 28.1 °.
[0083]
  The sipe 44 has a shape in which the D direction of the virtual center plane V of the blade 40 is matched with the sipe depth direction and the E direction is matched with the sipe width direction. Therefore, the interval and height of the triangular cross section of the sipe 44 are the same as those of the blade, the distance J between the vertices of adjacent triangles is 2 mm, and the height difference K between the vertices is 1 mm (from the virtual center plane V). The height of 0.5K is 0.5 mm).
[Second Embodiment]
  Subsequently, the present inventionSecond embodimentA pneumatic tire according to the present invention will be described with reference to FIGS.Reference example and first embodimentSince only the sipe shape is different from this pneumatic tire, only the sipe and the blade used to form the sipe will be described. In addition,Reference example and first embodimentThe same reference numerals are given to the same constituent elements as those in FIG.
[0084]
  First, the shape of the blade forming the sipe will be described with reference to FIG. The blade 50 is formed in a zigzag shape in which convex portions 52 that are triangles having a height of 0.5 L in the cross section in the E direction protrude alternately on both sides of the virtual center plane V at intervals M, and each convex portion 52 is in the E direction. It extends in the D direction orthogonal to. The blade 50 thus formed has a virtual center plane V.Reference exampleThe sipe 24 is disposed at the same position as the sipe 24, and the block is vulcanized in the mold.
[0085]
  As shown in FIG. 7, the sipe 54 of the block 18 formed by the blade 50 has a virtual center plane V as viewed in plan from the tread 26.Reference exampleThe sipe 24 is provided at the same position. That is, when viewed in plan from the tread 26, the sipe 54 has a surface portion 56 (virtual center plane V) on the tread 26 and a bottom portion 58 (virtual center plane V) on the sipe bottom X as shown in FIG. Cross on the mold.
[0086]
  Further, when viewed from the side 20, the virtual center plane V of the sipe 54 is formed at the position of the sipe 24 in FIG. 4, and the virtual center plane V on the side 20 and the virtual center on the side 22 are formed. The plane V is crossed in the X shape.
[0087]
  Therefore,Reference exampleSimilar to the sipe 24, the sipe 54 passes through a point where the virtual center plane V of the surface portion 56 intersects with the virtual center plane V of the bottom portion 58, and extends from the tread surface 26 around the rotation axis Z perpendicular to the tread surface 26. The shape is twisted by an angle θ2 toward the sipe bottom.
[0088]
  When viewed from the side, the sipe 54 passes through a point where the virtual center plane V of the side surface 20 intersects with the virtual center plane V of the side surface 22, and the side surface is centered on the rotation axis Y substantially parallel to the tread surface 26. The shape is twisted by an angle θ12 from 20 toward the side surface 22.
[0089]
  As shown in FIG. 7, the sipe 54 is opposite to the first projection 55 a and the first projection 55 a that projects in the first direction relative to the virtual center plane V corresponding to the projection 52 of the blade 50. A second protrusion 55b protruding in a second direction.
[0090]
  When the pneumatic tire 10 thus formed is mounted on a vehicle and travels, the following effects can be obtained.
[0091]
  That is,Reference exampleSimilarly, since the sipe 54 is formed by being twisted by an angle θ2 in a plan view from the tread surface 26, various directions acting from the tread surface 26 of the block 18 as well as the force acting from the A direction by the frictional force are formed. The small blocks 18a to 18d abut against each other with a strong force. In particular, since the sipe 54 forms a concavo-convex portion having a triangular cross section in a plane parallel to the tread surface 26, the small blocks 18a to 18d are deformed (rotated) in the solid arrow direction by compression in the C direction. The concavo-convex portions of adjacent small blocks are strongly engaged with each other.
[0092]
  Therefore, the fall of the small blocks 18a to 18d can be further suppressed, and the snow and ice performance can be further improved.
[0093]
  Also,Reference exampleSimilarly, since the sipe 54 is twisted about the rotation axis Z by an angle θ2, the small blocks 18a to 18d are rotated clockwise in a plan view from the tread surface 26 by the ground pressure (solid line in FIG. 7). See arrow).
[0094]
  As a result of this rotation, a counterclockwise rotational moment (SAT) is generated in each of the small blocks 18a to 18d (see the broken line arrow in FIG. 7).
[0095]
  Therefore, the clockwise SAT (see FIG. 1 arrow) generated by the steel cord 19 arranged in parallel with the outermost reinforcing layer can be suppressed (reduced) by the counterclockwise SAT generated by each block 18. .
[0096]
  By the way, the position P1 of the rotation axis Z in plan view from the tread 26 isReference exampleSimilarly, it is preferable that 0.2 W ≦ P1 ≦ 0.8 W in the B direction from the side surface 20 toward the side surface 22. Further, the position P2 of the rotation axis Y in a side view from the side surface 20 is preferably in the range of 0.2F ≦ P2 ≦ 0.6F from the tread surface 26 toward the bottom (sipe bottom) in the C direction. By positioning the rotary shaft Z and the rotary shaft Y within this range, the rigidity of the small blocks 18a to 18d is increased, and the small blocks 18a to 18d can be prevented from falling. As a result, the ice / snow performance is further improved.
[0097]
  The size of the block 18 in this embodiment isReference exampleSimilarly, length L × width W × height H is 30 mm × 20 mm × 10 mm. The vertical depth F from the tread surface 26 of the sipe 54 is 8 mm. Further, the sipe 54 is formed on the side surface 20 so that the distance a from the end surface in the A direction of the block 18 and the distance a between adjacent sipes are 7 mm and the distance b to the other end surface is 9 mm. The distance b from the end surface in the A direction of the block 18 on the opposite side surface 22 is 9 mm, the distance a between adjacent sipes, and the distance a to the other end surface is 7 mm. It is the shape which connects with a straight line. Note that the twist angle θ2 of the sipe 54 is 11.4 °, and the twist angle θ12 is 28.1 °.
[0098]
  The sipe 54 has a shape in which the D direction of the virtual center plane V of the blade 50 is matched with the sipe depth direction and the E direction is matched with the sipe width direction. Therefore, the interval and height of the triangular cross section of the sipe 54 are the same as those of the blade 50, the distance M between the vertices of adjacent triangles is 1 mm, and the height difference L between the vertices is 1 mm (virtual center plane V The height 0.5L from the height is 0.5 mm).
[Third Embodiment]
  Next, the present inventionThird embodimentA pneumatic tire according to the present invention will be described with reference to FIG.Reference example, first and second embodimentsSince only the sipe shape is different from this pneumatic tire, the description of the blade used to form this sipe is replaced with the description of the sipe shape. In addition,Reference example, first and second embodimentsThe same reference numerals are given to the same constituent elements as those in FIG.
[0099]
  As shown in FIG. 9, the blade 60 is formed in a shape in which convex portions 62 having triangular cross-sections that alternately protrude on both sides of the virtual center plane V are continuous in the direction of arrow G inclined at a predetermined angle from both directions of the D direction and the E direction. Has been.
[0100]
  The blade 60 has a cross section in the D direction.First embodimentSimilarly, the convex part 62 which is a triangle with a height of 0.5K is formed in a zigzag shape that alternately protrudes at both sides of the virtual center plane V with a gap J. Further, the blade 60 has a cross section in the E direction,Second embodimentIn the same manner as above, convex portions 62 that are triangles having a height of 0.5 L are formed in a zigzag shape that alternately protrudes on both sides of the virtual center plane V at intervals M.
[0101]
  The blade 60 thus formed has a virtual center plane V.Reference exampleThe block is vulcanized and molded in the mold.
[0102]
  The sipe (not shown) of the block 18 formed by the blade 60 has a virtual center plane V.Reference exampleThe sipe 24 is provided at the same position. Therefore, the virtual center plane V of the sipe has a shape twisted by an angle θ2 from the tread surface 26 toward the sipe bottom about the rotation axis Z perpendicular to the tread surface 26 (see FIG. 7). Further, the virtual center plane V of the sipe has a shape twisted by an angle θ12 from the side surface 20 toward the side surface 22 about the rotation axis Y substantially parallel to the tread surface 26 (see FIG. 5).
[0103]
  When the pneumatic tire 10 thus formed is mounted on a vehicle and travels, the following effects can be obtained.
[0104]
  That is,Reference exampleSimilarly, since the sipe is twisted by an angle θ2 when viewed from the tread surface 26, the small block 18a is not only caused by the force acting from the A direction but also by the force from various directions acting from the tread surface 26 of the block 18. ˜18d are brought into contact with each other with a strong force.
[0105]
  In particular, since the sipe has an uneven portion having a triangular cross section in both the sipe depth direction and a plane parallel to the tread surface 26, the sipe is adjacent to each other with the sipe sandwiched by compression of the small blocks 18a to 18d in the C direction. The uneven surfaces of the small blocks are brought into contact with each other with a strong force, and the uneven portions of the adjacent small blocks are strongly meshed with each other by the rotational motion of the small blocks 18a to 18d accompanying the compression.
[0106]
  Therefore, the fall of the small blocks 18a to 18d can be further suppressed, and the snow and ice performance can be further improved.
[0107]
  Also,Reference exampleSimilarly, since the sipe has a shape twisted about the rotation axis Z by an angle θ2, the small blocks 18a to 18d rotate clockwise in a plan view from the tread surface 26 by the ground pressure.
[0108]
  Due to this rotation, a counterclockwise rotational moment (SAT) is generated in each of the small blocks 18a to 18d to restore the original shape.
[0109]
  Therefore, the clockwise SAT (see FIG. 1 arrow) generated by the steel cord 19 arranged in parallel with the outermost reinforcing layer can be suppressed (reduced) by the counterclockwise SAT generated by each block 18. .
[0110]
  By the way, the position P1 of the rotation axis Z in plan view from the tread 26 isReference exampleSimilarly, it is preferable that 0.2 W ≦ P1 ≦ 0.8 W in the B direction from the side surface 20 toward the side surface 22. Further, the position P2 of the rotation axis Y in a side view from the side surface 20 is preferably in a range of 0.2F ≦ P2 ≦ 0.6F from the tread surface 26 toward the bottom 30 (sipe bottom) in the C direction. By positioning the rotary shaft Z and the rotary shaft Y within this range, the rigidity of the small blocks 18a to 18d is increased, and the small blocks 18a to 18d can be prevented from falling. As a result, the ice / snow performance is further improved.
[0111]
  The size of the block 18 in this embodiment isReference exampleSimilarly, length L × width W × height H is 30 mm × 20 mm × 10 mm. The vertical depth F from the sipe tread 26 is 8 mm. Further, the sipe is formed on the side surface 20 so that the distance a from the end surface of the block 18 in the A direction, the distance a between adjacent sipes is 7 mm, and the distance b to the other end surface is 9 mm. In addition, the distance b from the end surface in the A direction of the block 18 on the opposite side surface 22 is 9 mm, the distance a between adjacent sipes, and the distance a to the other end surface is 7 mm. It is a shape connected by a straight line. The sipe twist angle θ2 is 11.4 °, and the twist angle θ12 is 28.1 °.
[0112]
  Note that the sipe has a shape in which the D direction of the virtual center plane V of the blade 60 matches the sipe depth direction and the E direction matches the sipe width direction. Accordingly, the interval and height of the triangular cross sections of the sipe are the same as those of the blade 60, the distance J between the vertices of adjacent triangles in the sipe width direction is 2 mm, and the height difference K between the vertices is 1 mm (virtual) The height 0.5K from the center plane V is 0.5 mm), the distance M between adjacent triangle vertices in the sipe depth direction is 1 mm, and the height difference L between vertices is 1 mm (virtual center) The height 0.5L from the surface V is 0.5 mm).
[Fourth Embodiment]
Furthermore, the present inventionFourth embodimentA pneumatic tire according to the above will be described with reference to FIG.Reference exampleSince only the block shape and the sipe shape are different from the pneumatic tire, only the block and the sipe will be described. In addition,Reference exampleThe same reference numerals are given to the same constituent elements as those in FIG.
[0113]
  In a plan view from the tread surface 74, the block 70 has a shape rotated from the bottom surface 72 having the same height as the main groove 14 on the tread surface by the angle θ 3 from the tread surface 74 toward the tread surface 74. That is, it has a shape twisted by an angle θ3 counterclockwise from the tread surface 74 toward the bottom surface 72 around the rotation axis U perpendicular to the tread surface 74.
[0114]
  Also, in the sipe 76 provided in the block 70, the surface portion 78 that is a straight line on the tread surface 74 and the bottom portion 80 that is a straight line on the sipe bottom cross in an X shape in plan view from the tread surface 74. That is, the sipe 76 is also twisted counterclockwise by the angle θ4 in the same direction as the block 18 from the tread surface 74 toward the sipe bottom about the rotation axis Z perpendicular to the tread surface 74.
[0115]
  Further, in the sipe 76, a first side surface portion 75 that is a straight line on the side surface 71 and a second side surface portion 77 that is a straight line on the side surface 73 are crossed in an X shape in a side view from the side surface 71. That is, the sipe 76 is also twisted from the first side surface portion 75 to the second side surface portion 77 by an angle θ13 (not shown) with a rotation axis Y (not shown) parallel to the tread surface 74 as a center. .
[0116]
  When the pneumatic tire 10 thus formed is mounted on a vehicle and travels, the following effects can be obtained.
[0117]
  That is,Reference exampleSimilarly, since the sipe 76 is formed by being twisted by the angle θ4, the small blocks 70a to 70d are not only caused by the force acting from the A direction but also by the forces from various directions acting from the tread surface 74 of the block 70. Abutted with a strong force.
[0118]
  Moreover, since the sipe 76 and the block 70 are twisted in the same direction, the small blocks 70a to 70d perform a clockwise rotational movement (see the solid line arrow in FIG. 10) in plan view from the tread surface 74, and adjacent small blocks. The two come into contact with each other with a stronger force.
[0119]
  Therefore, the falling of the small blocks 70a to 70d can be further suppressed, and the ice and snow performance can be further improved.
[0120]
  Also,Reference exampleSimilarly, since the sipe 76 is twisted about the rotation axis Z by an angle θ4, the small blocks 70a to 70d rotate clockwise in a plan view from the tread surface 74 by the ground pressure (the solid line in FIG. 10). See arrow).
[0121]
  Due to this rotation, a counterclockwise rotational moment (SAT) is generated in each of the small blocks 70a to 70d (see the broken line arrow in FIG. 10).
[0122]
  At the same time, since the block 70 is also twisted about the rotation axis U by an angle θ3, the block 70 is rotated clockwise in the plan view from the tread surface 74 by the ground pressure (see the solid line arrow in FIG. 10).
[0123]
  As a result of this rotation, a counterclockwise rotational moment (SAT) is also generated in the block 70 (see the thick broken line arrow in FIG. 10).
[0124]
  As described above, in the block 70 of this embodiment, the block 70 and the sipe 76 are formed in a shape twisted in the same direction, so that a stronger SAT can be generated.
[0125]
  Therefore, the clockwise SAT (see arrow in FIG. 1) generated by the steel cord 19 arranged in parallel to the outermost reinforcing layer is suppressed by the counterclockwise rotational moment generated by the block 70 and the small blocks 70a to 70d ( Reduction).
[0126]
  By the way, the position P1 of the rotation axis Z in plan view from the tread surface 74 is:Reference exampleSimilarly, it is preferable that 0.2 W ≦ P1 ≦ 0.8 W in the B direction from the side surface 20 toward the side surface 22. Further, the position P2 of the rotation axis Y in a side view from the side surface 71 is preferably in the range of 0.2F ≦ P2 ≦ 0.6F from the tread surface 26 toward the bottom 30 in the C direction. By positioning the rotary shaft Z and the rotary shaft Y within this range, the rigidity of the small blocks 18a to 18d is increased, and the small blocks 18a to 18d can be prevented from falling. As a result, the ice / snow performance is further improved.
[0127]
  The size of the block 70 in this embodiment is as follows.Reference exampleSimilarly to the block 18, the length L × width W × height H is 30 mm × 20 mm × 10 mm (see FIG. 2). Further, the vertical depth F from the tread surface 74 of the sipe is 8 mm. The twist angle θ3 about the rotation axis U of the block 70 is 5 °.
[0128]
  Further, the sipe 76 is formed on the side surface 82 at a position where the distance a from the end surface of the block 70 in the A direction, the distance a between adjacent sipes is 7 mm, and the distance b to the other end surface is 9 mm. 84, the distance b from the end surface in the A direction of the block 70 is 9 mm, the distance a between adjacent sipes, and the distance a to the other end surface are 7 mm, and the both end surfaces are connected by a straight line. Note that the twist angle θ4 of the sipe 76 is 11.4 °, and the twist angle θ13 is 28.1 °.
[Fifth Embodiment]
  Further, the present inventionFifth embodimentA pneumatic tire according to the present invention will be described with reference to FIG.Reference exampleSince only the block shape and the sipe shape are different from the pneumatic tire, only the block and the sipe will be described. In addition,Reference exampleThe same reference numerals are given to the same constituent elements as those in FIG.
[0129]
  As shown in FIG. 11, the block 90 in a plan view from the tread surface 94 has a shape that is rotated by an angle θ5 from the bottom surface 92 having the same height as the main groove 14 toward the tread surface 94 on the tread surface. That is, it has a shape twisted by an angle θ5 clockwise from the tread surface 94 toward the bottom surface 92 about the rotation axis U perpendicular to the tread surface 94.
[0130]
  Also, in the sipe 96 provided in the block 90, the surface portion 98 that is straight on the tread surface 94 and the bottom portion 100 that is straight on the sipe bottom cross in an X shape in plan view from the tread surface 94. That is, the sipe 96 also has a shape twisted by an angle θ6 counterclockwise in the direction opposite to the block 18 from the tread surface 94 toward the sipe bottom about the rotation axis Z perpendicular to the tread surface 94.
[0131]
  Further, in the sipe 96, a first side surface portion 95 that is a straight line on the side surface 91 and a second side surface portion 97 that is a straight line on the side surface 93 are crossed in an X shape in a side view from the side surface 91. That is, the sipe 96 has a shape twisted from the first side surface portion 95 to the second side surface portion 97 by an angle θ14 (not shown) around a rotation axis Y (not shown) parallel to the tread surface 94. .
[0132]
  When the pneumatic tire 10 thus formed is mounted on a vehicle and travels, the following effects can be obtained.
[0133]
  That is,Reference exampleSimilarly, since the sipe 96 is formed by being twisted by the angle θ6, the small blocks 90a to 90d are not only moved by the force acting from the A direction but also by the forces from various directions acting from the tread surface 94 of the block 90. Abutted with a strong force.
[0134]
  Furthermore, since the sipe and the block are twisted in the opposite directions, the opposite rotational force acts on the small blocks.by thisAdjacent small blocks abut against each other very strongly.
[0135]
  Therefore, the falling of the small blocks 90a to 90d can be further suppressed, and the snow and ice performance can be further improved.
[0136]
  Also,Reference exampleSimilarly, since the sipe 96 is twisted about the rotation axis Z by an angle θ6, the small blocks 90a to 90d are rotated clockwise in a plan view from the tread surface 94 by the ground pressure (solid line in FIG. 11). See arrow).
[0137]
  Due to this rotation, a counterclockwise rotational moment (SAT) is generated in each of the small blocks 90a to 90d (see the broken line arrow in FIG. 11).
[0138]
  At the same time, since the block 90 is also twisted about the rotation axis U by an angle θ5, the block 90 is rotated counterclockwise in plan view from the tread surface 94 by the contact pressure (see the solid line arrow in FIG. 11). .
[0139]
  As a result of this rotation, a clockwise rotational moment (SAT) is also generated in the block 90 to restore the original shape.
[0140]
  Therefore, this difference in rotational moment is the SAT generated in the block 90.
[0141]
  Therefore, by disposing the block 90 in an appropriate direction on the surface of the tread 12, the SAT (see the arrow in FIG. 1) generated by the steel cord 19 disposed in parallel to the outermost reinforcing layer is reduced to the block 90 and the small block. It can be suppressed (reduced) by the SAT generated by 90a to 90d.
[0142]
  By the way, the position P1 of the rotation axis Z in plan view from the tread surface 94 isReference exampleSimilarly, it is preferable that 0.2 W ≦ P1 ≦ 0.8 W in the B direction from the side surface 20 toward the side surface 22. Further, the position P2 of the rotation axis Y in a side view from the side surface 91 is preferably in the range of 0.2F ≦ P2 ≦ 0.6F from the tread surface 26 toward the bottom 30 in the C direction. By positioning the rotary shaft Z and the rotary shaft Y within this range, the rigidity of the small blocks 18a to 18d is increased, and the small blocks 18a to 18d can be prevented from falling. As a result, the ice / snow performance is further improved.
[0143]
  The size of the block 90 in this embodiment isReference exampleSimilarly to the block 18, the length L × width W × height H is 30 mm × 20 mm × 10 mm (see FIG. 2). The vertical depth F from the sipe tread 94 is 8 mm. The twist angle θ5 about the rotation axis U of the block 90 is 5 °.
[0144]
  The sipe 96 is formed on the side surface 102 at a position where the distance a from the end surface in the A direction of the block 90 and the distance a between adjacent sipes are 7 mm, and the distance b to the other end surface is 9 mm. In 104, a distance b from the end surface in the A direction of the block 90 is 9 mm, a distance a between adjacent sipes, and a distance a to the other end surface are 7 mm, and the both end surfaces are connected by a straight line. Note that the twist angle θ6 of the sipe 96 is 11.4 °, and the twist angle θ14 is 28.1 °.
[Sixth Embodiment]
  Next, the present inventionSixth embodimentA pneumatic tire according to the above will be described with reference to FIGS. 12 and 13.Reference exampleSince only the sipe shape is different from this pneumatic tire, only the sipe will be described. In addition,Reference exampleThe same reference numerals are given to the same constituent elements as those in FIG.
[0145]
  The sipe 110 formed in the block 18 is a closed loop having a quadrangular AB cross section. The sipe 110 has the same shape as the rectangular surface portion 112 at the tread surface 26 and the surface portion 112 at the bottom of the sipe, and rotates by an angle θ7 in plan view from the tread surface 26. The rectangular bottom surface portion 114 located at the position where it is connected is continuously connected. That is, the sipe 110 has a shape twisted by an angle θ7 counterclockwise from the tread surface 26 toward the sipe bottom about the rotation axis Z perpendicular to the tread surface 26. The tread 26 side of the block 18 is divided by the sipe 110 into an inner small block 18e and an outer small block 18f.
[0146]
  When the pneumatic tire 10 thus formed is mounted on a vehicle and travels, the following effects can be obtained.
[0147]
  The block 18 is compressed in the C direction by the contact pressure and expanded in the A direction and the B direction, so that the small blocks 18e and 18f facing each other across the sipe 110 come into contact. At this time, the small block 18e is guided by the sipe 110 and further deformed in the clockwise twisting direction, so that it contacts the small block 18f with a strong force.
[0148]
  Therefore, the snow and ice performance of the pneumatic tire 10 is improved by suppressing the falling of the small blocks 18e and 18f and increasing the contact area on the tread 26.
[0149]
  Also,Reference exampleSimilarly, since the sipe 110 is twisted about the rotation axis Z by an angle θ7, the small block 18e is rotated clockwise in a plan view from the tread surface 26 by the ground pressure (see solid arrows in FIG. 12). ).
[0150]
  As a result of this rotation, a counterclockwise rotational moment (SAT) is generated in the small block 18e (see the broken line arrow in FIG. 12).
[0151]
  Accordingly, the clockwise SAT (see FIG. 1 arrow) generated by the steel cord 19 disposed in parallel with the outermost reinforcing layer can be suppressed (reduced) by the counterclockwise SAT generated by the small block 18e. .
[0152]
  The size of the block 18 in this embodiment isReference exampleSimilarly, length L × width W × height H is 30 mm × 20 mm × 10 mm. Further, the vertical depth F from the sipe tread 26 is 8 mm.
[0153]
  The sipe 110 is formed on the tread surface 26 at a position where the distance c from the end surface in the A direction and the end surface in the B direction of the block 18 is 6 mm. The twist angle θ7 of the sipe 110 is 5 °.
[Seventh Embodiment]
  Next, the present inventionSeventh embodimentA pneumatic tire according to the above will be described with reference to FIGS. 14 and 15.Reference exampleSince only the block shape and the sipe shape are different from the pneumatic tire, only the block and the sipe will be described. Note that the same reference numerals are given to the same components as those in the seventh embodiment, and detailed description thereof will be omitted.
[0154]
  The block 120 has a shape in which a bottom surface 122 having the same height as the main groove on the tread surface and a tread surface 124 at a position rotated by an angle θ8 in plan view are continuous with the bottom surface 122. That is, it has a shape twisted counterclockwise by an angle θ8 from the tread surface 124 toward the bottom surface 122 about the rotation axis U perpendicular to the tread surface 124.
[0155]
  In addition, the sipe 126 that is a closed loop that circulates in a quadrilateral shape provided in the block 120 also includes a tread surface 124 that has a rectangular surface portion 128 on the tread surface 124 and a bottom portion 130 that is the same shape as the surface portion 128 on the sipe bottom. Is rotated by an angle θ9 in plan view. That is, the sipe 126 also has a shape rotated about the rotation axis Z perpendicular to the tread surface 124 from the tread surface 124 toward the bottom of the sipe by an angle θ9 counterclockwise in the same direction as the block 120. In the present embodiment, the angle θ8 and the angle θ9 are the same, but may be different.
[0156]
  The tread surface 124 side of the block 120 is divided by the sipe 126 into an inner small block 120e and an outer small block 120f.
[0157]
  When the pneumatic tire 10 thus formed is mounted on a vehicle and travels, the following effects can be obtained.
[0158]
  The block 120 is compressed in the C direction by the contact pressure and expanded in the A direction and the B direction, so that the small blocks 120e and 120f facing each other across the sipe 126 come into contact.
[0159]
  Therefore, the snow and ice performance of the pneumatic tire 10 is improved by suppressing the falling of the small blocks 120e and 120f and increasing the contact area on the tread surface 124.
[0160]
  Also,Reference exampleSimilarly, since the sipe 126 is twisted about the rotation axis Z by an angle θ9, the small block 120e is rotated clockwise in a plan view from the tread surface 124 by the ground pressure (see solid arrows in FIG. 14). ).
As a result of this rotation, a counterclockwise rotational moment (SAT) is generated in the small block 120e (see the broken line arrow in FIG. 14).
[0161]
  Further, since the block 120 is twisted about the rotation axis U by an angle θ8, the block 120 rotates clockwise in a plan view from the tread surface 124 by the ground pressure (see the solid line arrow in FIG. 14).
[0162]
  As a result of this rotation, a counterclockwise rotational moment (SAT) is generated in the block 120 to restore the original shape (see the broken line arrow in FIG. 14).
[0163]
  As described above, in the block 120, since the rotational moment (SAT) generated by the twist of the block 120 itself and the twist of the sipe 126 is in the same direction, a stronger SAT is generated.
[0164]
  Therefore, the clockwise SAT (see the arrow in FIG. 1) generated by the steel cord 19 arranged in parallel with the outermost reinforcing layer can be more strongly suppressed (reduced) by the counterclockwise SAT generated by the block 120. it can.
[0165]
  The size of the block 120 in this embodiment isReference exampleSimilarly, length L × width W × height H is 30 mm × 20 mm × 10 mm. The vertical depth F from the tread surface 124 of the sipe 126 is 8 mm. A twist angle θ8 about the rotation axis U of the block 120 is 5 °.
[0166]
  In the tread surface 124, the distance c from the end surface in the A direction and the end surface in the B direction to the sipe 126 is 6 mm. The twist angle θ9 about the rotation axis Z of the sipe 126 is 5 °.
[Eighth Embodiment]
  Finally, the present inventionEighth embodimentA pneumatic tire according to the above will be described with reference to FIGS. 16 and 17.Reference exampleSince only the block shape and the sipe shape are different from the pneumatic tire, only the block and the sipe will be described. Note that the same reference numerals are given to the same components as those in the seventh and eighth embodiments, and detailed description thereof will be omitted.
[0167]
  The block 140 has a shape in which a bottom surface 142 having the same height as the main groove 14 on the tread surface and a tread surface 144 at a position rotated by an angle θ10 in a plan view are continuous. That is, it has a shape twisted by an angle θ10 counterclockwise from the tread surface 144 toward the bottom surface 142 around the rotation axis U perpendicular to the tread surface 144.
[0168]
  Also, the sipe 146 that is a closed loop that circulates in a square shape provided in the block 140 also rotates the surface portion 148 of the tread surface 144 and the bottom portion 150 that is the sipe bottom clockwise by an angle θ11 in plan view from the tread surface 144. is doing. That is, the sipe 146 also has a shape rotated about the rotation axis Z perpendicular to the tread surface 144 from the tread surface 144 toward the sipe bottom by an angle θ11 in the clockwise direction opposite to the block 140.
[0169]
  The tread surface 144 side of the block 140 is divided by the sipe 146 into an inner small block 140e and an outer small block 140f.
[0170]
  When the pneumatic tire 10 thus formed is mounted on a vehicle and travels, the following effects can be obtained.
[0171]
  The block 140 is compressed in the C direction by the contact pressure and expanded in the A direction and the B direction, so that the small blocks 140e and 140f facing each other across the sipe 146 come into contact. At this time, the small block 140e attempts to rotate counterclockwise due to the contact pressure, and the small block 140f attempts to rotate clockwise due to torsion of the block 140. 140f are brought into contact with each other with a stronger force.
[0172]
  Therefore, the snow block performance of the pneumatic tire 10 is improved by further suppressing the falling of the small blocks 140e and 140f and increasing the contact area on the tread surface 144.
[0173]
  Also,Reference exampleSimilarly, since the sipe 146 has a shape twisted about the rotation axis Z by an angle θ11, the small block 140e rotates counterclockwise in a plan view from the tread surface 144 by the ground pressure (solid arrow in FIG. 16). reference).
As a result of this rotation, a clockwise rotational moment (SAT) is generated in the small block 140e (see the broken line arrow in FIG. 16).
[0174]
  On the other hand, since the block 140 is twisted about the rotation axis U by an angle θ10, the block 140 rotates clockwise in a plan view from the tread surface 144 by the ground pressure (see the solid line arrow in FIG. 16).
[0175]
  This rotation causes a counterclockwise rotational moment (SAT) to be restored to the original shape in the block 140 (see the broken line arrow in FIG. 16).
[0176]
  Therefore, the rotational moment (SAT) generated in the entire block 140 is a difference between the rotational moment (SAT) generated by the twist of the block 140 itself and the twist of the sipe 146.
[0177]
  Accordingly, by disposing the block 140 in an appropriate direction on the surface of the tread 12, the block 140 generates the SAT (see the arrow in FIG. 1) generated by the steel cord 19 disposed in parallel to the outermost reinforcing layer. It can be suppressed (reduced) by SAT.
[0178]
  The size of the block 140 in this embodiment isReference exampleSimilarly, length L × width W × height H is 30 mm × 20 mm × 10 mm. Further, the vertical depth F from the tread surface 144 of the sipe is 8 mm. A twist angle θ10 about the rotation axis U of the block 140 is 5 °.
[0179]
  The sipe 146 is formed on the tread surface 144 at a position where the distance c from the end surface in the A direction and the end surface in the B direction of the block 140 is 6 mm. A twist angle θ11 about the rotation axis Z of the sipe 146 is 5 °.
[0180]
  Note that the angle θ10 and the angle θ11 may be the same or different.
[Test example]
  Next, the SAT and block deformation amount tests performed using the sample blocks, and the on-ice brake performance tests performed using actual tires will be described with reference to FIGS.
[0181]
  First, the SAT test will be described. The sample block corresponds to a block of a pneumatic tire.Reference examples, Examples 1-8RespectivelyComparative example 1, first to eighth embodimentsIt is a block.
[0182]
  As shown in FIG. 18, the block 18 of the comparative example 1 is provided with a sipe 152 that is a double-sided opening type and that is formed in a straight line whose sipe depth direction is parallel to the C direction. The size of block 18 isReference exampleSimilarly to the block 18, the length L × width W × height H is 30 mm × 20 mm × 10 mm. The vertical depth F from the tread surface 26 of the sipe 152 is 8 mm. Further, the surface portion 154 of the side surfaces 20 and 22 is formed at a position where the distance f from the end surface in the A direction of the block 18 is 8 mm and the distance g between adjacent sipes is 7 mm.
[0183]
  Moreover, the comparative example 2 is the block 18 in which the sipe 162 which is a square closed loop was formed, as shown in FIG. The size isSixth embodimentSimilarly to the block 18, the length L × width W × height H is 30 mm × 20 mm × 10 mm. Further, the vertical depth F from the sipe tread 26 is 8 mm. The sipe 162 is provided on the tread surface 26 at a position where the distance c from the end surface in the A direction and the end surface in the B direction of the block 18 is 6 mm.
[0184]
  There is no portion twisted with any of the blocks of Comparative Example 1 and Comparative Example 2.
[0185]
  like thisReference examples, Examples 1-8The SAT is shown when the blocks of Comparative Examples 1 and 2 are pressed perpendicularly to the road surface and compressed to 10% of the block height. The test results are shown in FIG. The unit is kgf · m. Here, the counterclockwise direction when viewed in plan from the tread is +, and the clockwise direction is −.
[0186]
  Reference examples, Examples 1-5As compared with Comparative Example 1, it can be seen that the sipe is twisted, so that the small block is rotated by the ground pressure and SAT is generated.Reference example, Examples 1-3In FIG. 3, it can be seen that the effect of providing the sipe with irregularities having a triangular cross section is insignificant, and that torsion greatly affects the SAT.
[0187]
  Also added twist to sipe and blockExample 4WhenExample 5When the sipe and the block are twisted in the same direction, Example 5 in which the sipe and the block are twisted in the same direction generates SAT that is larger in absolute value than in Example 6.
[0188]
  Examples 6-8As compared with Comparative Example 2, it can be seen that the sipe is twisted, so that the small block is rotated by the ground pressure, and SAT is generated. In particular, the block was twistedExamples 7 and 8Added torsion of sipe and block in the same directionExample 7Then, it can be seen that a very large SAT is generated.
[0189]
  Next, a test for examining the amount of deformation using the same sample block was performed. Load the block on ice 2.2kgf / cm² The amount of displacement in the A direction at the end of the tread surface of the sample block was examined while the ice was moved relative to the sample block at a speed of 20 km / h. The test results are shown in FIG. The unit is mm.
[0190]
  Reference examples, Examples 1-5Compared with Comparative Example 1, it can be seen that, by twisting the sipe, the small blocks are rotated by the contact pressure and are strongly brought into contact with each other, so that the collapse (deformation amount) is suppressed.Reference example, Examples 1-3In, the sipe was provided with irregularities of triangular cross-sectionExamples 1-3Has further suppressed the amount of deformation, and the sipe was formed to mesh with the small blocks, especially by rotational deformationExamples 2 and 3Has further suppressed the collapse (deformation amount).
[0191]
  Also, the block was twistedExamples 4 and 5Then, since the sixth embodiment in which twists in opposite directions are applied to the sipe and the block, the rotational forces in the opposite directions are applied to strongly contact the small blocks, so that the collapse (deformation amount) is suppressed more effectively. Yes.
[0192]
  Examples 6-8Compared with Comparative Example 2, it can be seen that since the sipe is twisted, the small block is rotated by the contact pressure and comes into contact with the adjacent small block, so that the collapse (deformation amount) is suppressed. In particular, the block was twistedExamples 7 and 8Then, the twist of the opposite direction was added to the sipe and the blockExample 8However, since the small blocks are strongly in contact with each other, the collapse (deformation amount) is suppressed more effectively.
[0193]
  Subsequently, an on-ice brake performance test was conducted with a pneumatic tire mounted on the actual vehicle. The tire size is 185 / 70R14. Used in a series of testsComparative Example 1, Examples 1-8 and Comparative Examples 2, 3Tires of eachReference examples, Examples 1-8And it is the pneumatic tire in which the block of the same shape as the sample block of Comparative Examples 1 and 2 was formed on the tread surface.
[0194]
  In the brake test on ice, a tire is mounted on a vehicle, and the braking distance is measured by applying a sudden brake while traveling on an icy road surface at a speed of 20 km / h. The test results represent the braking performance on ice with the reciprocal of the braking distance as an index. The larger the index, the better the braking performance on ice. The test results are shown in FIG. The on-ice brake performance of Comparative Example 1 is assumed to be 100.
[0195]
  On-ice brake performanceReference exampleCompared withComparative Example 1, Examples 1-8The brake performance on ice will be good.
[0196]
  next,Fourth embodimentThe block twist angle θ3 and the sipe twist angle θ4 in the block 70 are the same angle, and several sample blocks in which the angle θ3 (= θ4) is changed are used. I investigated the relationship. The results are shown in the graph of FIG.
[0197]
  Thus, the amount of displacement decreases basically as the torsional angles θ3 and θ4 increase. That is, as the torsional angles θ3 and θ4 increase, the block can be further prevented from falling. However, if the twist angle is too large when the block is removed from the mold during the manufacturing process, the block will be lost. From this manufacturing limit, it is preferable that the twist angles θ3 and θ4 of the block and sipe are 0 ° <θ3 (= θ4) ≦ 50 °.
[0198]
  Further, a test was performed on the relationship between the position of the rotation axis Z corresponding to the first torsion rotation axis and the rigidity of the small block.
[0199]
  A sample block is shown in FIG.Reference exampleA plurality of rotating shafts Z were prepared in different positions in the arrow B direction. That is, changes in the amount of displacement in the A direction of the small blocks 18a to 18d with respect to the position of the rotation axis Z were examined. In the test, the block is loaded on ice with a load of 2.2 kgf / cm.² The amount of displacement in the A direction at the end of the tread surface of the sample block was examined while the ice was moved relative to the sample block at a speed of 20 km / h.
[0200]
  The test results are shown in FIG. Here, the horizontal axis indicates the position in the B direction of the rotation axis Z in the block 18, and the number indicates the distance from the side surface 20 as a percentage of the width W. The vertical axis represents the rigidity ratio when the reciprocal of the displacement amount in the A direction of the small block is 100 when the rotation axis Z is positioned on the side surface 20.
[0201]
  As shown in FIG. 24, when the position (P1) of the rotation axis Z is in the range of 20% to 80% of the width W (0.2W ≦ P1 ≦ 0.8W), the rigidity of the small block is further increased, and it falls down. It has been confirmed that this is further prevented.
[0202]
  Next, the relationship between the position of the rotation axis Y corresponding to the second torsion rotation axis and the rigidity of the small block was examined.
[0203]
  A sample block is shown in FIG.Reference exampleA plurality of the rotating shafts Y are prepared which are substantially the same as those in FIG. That is, the change in the displacement amount in the A direction of the small blocks 18a to 18d with respect to the position of the rotation axis Y was examined. In the test, the block is loaded on ice with a load of 2.2 kgf / cm.² The amount of displacement in the A direction at the end of the tread surface of the sample block was examined while the ice was moved relative to the sample block at a speed of 20 km / h.
[0204]
  The test results are shown in FIG. Here, the horizontal axis indicates the position of the rotation axis Z in the block 18 in the C direction, and the number indicates the distance from the tread surface 26 as a percentage of the vertical depth F of the sipe 24. The vertical axis represents the rigidity ratio when the reciprocal of the amount of displacement in the A direction of the small block when the rotation axis Y is positioned on the tread 26 is 100.
[0205]
  As shown in FIG. 25, the rigidity of the small block is much higher when the position (P2) of the rotation axis Y is in the range of 20% to 60% (0.2F ≦ P2 ≦ 0.6F) of the vertical depth F of the sipe 24. It has been confirmed that the fall is further prevented.
[0206]
  In the above two tests,Reference exampleOnly the results of tests performed on sample blocks similar toFirst to fifth embodimentsThe above two tests were also performed on sample blocks substantially the same as those described above, and similar test results were obtained.
[0207]
【The invention's effect】
  Since the present invention has the above-described configuration, it is possible to suppress the collapse of the block to ensure good ice and snow performance, and to satisfactorily suppress SAT generated by the cord arrangement direction of the reinforcing layer closest to the tread surface. . As a result, a vehicle equipped with such a pneumatic tire can obtain good steering stability.
[Brief description of the drawings]
[Figure 1]Reference exampleIt is a tread top view of the pneumatic tire concerning.
[Figure 2]Reference exampleIt is a perspective view of the block concerning.
[Fig. 3]Reference exampleIt is a top view of the block concerning.
[Fig. 4]Reference exampleIt is a side view of the block concerning.
FIG. 5 of the present inventionFirst embodimentIt is a side view of the block concerning.
FIG. 6 of the present inventionFirst embodimentIt is shape explanatory drawing of the blade which concerns on.
[Fig. 7] of the present invention.Second embodimentIt is a top view of the block concerning.
[Fig. 8] of the present inventionSecond embodimentIt is shape explanatory drawing of the blade which concerns on.
FIG. 9 shows the present invention.Third embodimentIt is shape explanatory drawing of the blade which concerns on.
FIG. 10 shows the present invention.Fourth embodimentIt is a top view of the block concerning.
FIG. 11 shows the present invention.Fifth embodimentIt is a top view of the block concerning.
FIG. 12 shows the present invention.Sixth embodimentIt is a top view of the block concerning.
FIG. 13 shows the present invention.Seventh embodimentIt is a side view of the block concerning.
FIG. 14 shows the present invention.Seventh embodimentIt is a top view of the block concerning.
FIG. 15 shows the present invention.Seventh embodimentIt is a side view of the block concerning.
FIG. 16 shows the present invention.Eighth embodimentIt is a top view of the block concerning.
FIG. 17 shows the present invention.Eighth embodimentIt is a side view of the block concerning.
18 is a perspective view of a block according to Comparative Example 1. FIG.
FIG. 19 is a perspective view of a block according to Comparative Example 2;
FIG. 20 is a diagram showing a SAT test result.
FIG. 21 is a diagram showing a displacement amount test result.
FIG. 22 is a diagram showing the results of an on-ice brake performance test.
FIG. 23 is a graph showing a relationship between a twist angle and a displacement amount.
FIG. 24 is a graph showing the relationship between the position of a rotating shaft and the rigidity of a small block.
FIG. 25 is a graph showing the relationship between the position of a rotating shaft and the rigidity of a small block.
[Explanation of symbols]
        10 Pneumatic tire
        12 tread
        14 Main groove
        16 lug groove
        18 blocks (block land)
        19 Steel cord
        24 Sipe
        26 Tread
        28 Surface
        30 Bottom
          Z Rotation axis (first torsion center axis)
          Y rotation axis (second torsion center axis)

Claims (7)

A plurality of reinforcing layers arranged in parallel with a cord inclined at a predetermined angle with respect to the tire circumferential direction;
A tread provided on top of the laminated reinforcing layer;
In the tread surface, a block land portion defined by a main groove formed in the tire circumferential direction and a lug groove formed in a direction intersecting the main groove;
A plurality of sipes traversing the block land,
A pneumatic tire comprising:
The sipe has a zigzag shape that alternately protrudes on both sides of the virtual center plane from the tread of the block-shaped land portion toward the sipe bottom, or a zigzag shape that alternately protrudes on both sides of the virtual center plane in the sipe longitudinal direction A pneumatic tire characterized in that the zigzag virtual center plane is twisted from a surface portion exposed on the tread surface of the block-shaped land portion toward a sipe bottom . The virtual center plane has a shape twisted around a first torsion center axis extending in the tire radial direction in the block-shaped land portion, and a position P1 of the first torsion center axis is a tire. 2. The pneumatic tire according to claim 1 , wherein the pneumatic tire is within a range satisfying the following relational expression between one end face and the other end face of the block-shaped land portion in the width direction.
0.2W ≦ P1 ≦ 0.8W
Here, P1 is the position of the first torsional central axis,
W is the distance from one end surface of the block-shaped land portion to the other end surface in the tire width direction. The virtual center plane has a shape twisted around a second torsion center axis extending substantially in the tire width direction in the block-shaped land portion, and a position P2 of the second torsion center axis is The pneumatic tire according to claim 1 or 2 , wherein the pneumatic tire is within a range satisfying the following relational expression between the tread surface and the sipe bottom in the tire radial direction.
0.2F ≦ P2 ≦ 0.6F
Here, P2 is the position of the second torsional central axis,
F is the distance from the tread surface to the sipe bottom in the tire radial direction,
It is. A plurality of reinforcing layers arranged in parallel with a cord inclined at a predetermined angle with respect to the tire circumferential direction;
A tread provided on top of the laminated reinforcing layer;
On the tread surface, a sipe-containing block land portion defined by a main groove formed in the tire circumferential direction and a lug groove formed in a direction intersecting the main groove;
A pneumatic tire comprising:
The sipe has a closed loop shape that does not communicate with the main groove and the lug groove, and includes a surface portion exposed on the tread surface of the block-shaped land portion and a bottom portion formed on the sipe bottom, from the surface portion. A pneumatic tire that is twisted toward the bottom. The pneumatic tire according to any one of claims 1 to 4 , wherein the block-shaped land portion is twisted from the tread surface toward the base portion. The pneumatic tire according to claim 5, wherein the twisting direction of the block-shaped land portion is the same as the twisting direction from the tread surface of the sipe toward the sipe bottom. 6. The pneumatic tire according to claim 5, wherein the twisting direction of the block-shaped land portion is opposite to the twisting direction from the tread surface of the sipe toward the sipe bottom.

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