JPH11240314A - Pneumatic tire - Google Patents

Abstract

PROBLEM TO BE SOLVED: To suppress falling of blocks in a pneumatic tire by satisfying specified relation between a twisting center axis in a radial direction of a tire, with a spacing between end faces of widthwise blocks, and satisfying specified relation between the twisting center axis in widthwise direction of the tire, with a spacing between an operation surface in a radial direciton of the tire and the bottoms of the sipes. SOLUTION: Sipes 24 each twisted by a specified angle from a surface part 28 to a bottom part 30 are arranged in a block 18. A rotary axis is arranged, in a plan view from an operation surface 26, within a range indicated by the following formula: 0.2W<=P1 <=0.8W from a side surface 20 to a side surface 22, where P1 is a position of the rotary axis in a plan view, W is width of the block 18 in a B direction. The rotary axis is arranged, in a side view from the side surface 20 from the operation surface 26 to the bottoms of the sipes in a C direction, within a range indicated by the following formula: 0.2F<=P2 <=0.6F, where P2 is a position of the rotary shaft in the side view, and F is the depth of the sipe 24 in the C direction. Rigidity of small blocks 18a to 18d is thus increased, while falling of the blocks 18a to 18d is prevented.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a pneumatic tire exhibiting good ice and snow performance.

[0002]

2. Description of the Related Art Conventionally, there is a pneumatic tire provided with a plurality of blocks formed on a tread surface by a main groove formed in a tire circumferential direction and a lug groove formed in a tire width direction. Thus, by providing the block on the tread surface, the pneumatic tire ensures good braking / driving force, steering stability, and the like.

Further, a sipe is provided in the block to increase the edge length, thereby increasing the grip force, thereby improving the ice and snow performance and the wet performance.

[0004] Further, a reinforcing layer in which a number of steel cords are arranged in parallel is laminated below the tread surface of the pneumatic tire thus formed in order to increase the rigidity of the tread.

[0005]

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 tries to fall down due to the frictional force with the ground contact surface when the tire rotates. When the fall is large, the contact area on the tread is reduced, and ice and snow performance may be reduced.

However, the small block is compressed in the height direction (direction in which the tire axis is directed from the tread surface) by the contact pressure from the tread surface and swells in the lateral direction (direction perpendicular to the height direction). It comes into contact with an adjacent small block, and the fall is suppressed to some extent.

However, in a sipe formed straight in the depth direction of the sipe, the deformation of the small block only by the contact pressure cannot contact the adjacent small block with sufficient force, and the suppression of falling down is small. It was hard to say that the ground contact area was sufficient.

In addition, a plurality of steel cords arranged on each reinforcing layer are arranged in parallel at a predetermined angle with respect to the tire circumferential direction. Therefore, when the pneumatic tire is actually mounted on the vehicle and traveled, the tire deformed by the ground pressure is restored to its original shape by the inclination of the steel cord disposed on the reinforcement layer closest to the tread surface side with respect to the tire circumferential direction. Force (Self Alignment)
Torque (hereinafter referred to as SAT) occurs.

In view of the above, it is an object of the present invention to provide a pneumatic tire that suppresses the fall of a sipe-containing block, exhibits good ice and snow performance, and suppresses SAT.

[0010]

According to the first aspect of the present 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, and a plurality of reinforcing layers are provided on the stacked reinforcing layers. A tread provided, and a sipe-containing block-shaped land portion defined by a main groove formed in a tire circumferential direction on the tread surface and a lug groove formed in a direction intersecting the main groove. In the pneumatic tire, the sipe twists around a first torsion center axis extending in a tire radial direction and a second torsion center axis extending substantially in a tire width direction in the block-shaped land portion. And the position P1 of the first torsion center axis is between the one end face and the other end face of the block-like land portion in the tire width direction, and the position of the second torsion center axis is Position P2 is the tire In between the tread in the radial direction to the sipe bottom, characterized in that in the range satisfying the following relational expression.

0.2W ≦ P1 ≦ 0.8W 0.2F ≦ P2 ≦ 0.6F Here, P1 and P2 are the positions of the first and second torsion center axes, respectively, and W is the block land. F is a distance from one end face in the tire width direction to the other end face in the tire width direction, and F is a distance from the tread surface to the sipe bottom in the tire radial direction.

The operation of the first aspect of the present invention will be described.

The sipe is twisted about a first torsion central axis extending in the tire radial direction and a second torsion central axis extending substantially in the tire width direction. When the portion is compressed in the height direction by the contact pressure and expands in the horizontal direction, the small blocks divided by the sipe come into contact with each other. Further, since the sipes are twisted, the small blocks come into contact with each other not only by a force acting in the tire circumferential direction (tire rotation direction) but also by a force acting in another direction. Further, since the small blocks rotate by the contact pressure, the adjacent small blocks come into contact with each other with a strong force.

Further, the position P1 of the first torsion center axis is set at 0. 0 to the distance W (hereinafter referred to as width W) from one end face of the block-shaped land portion to the other end face in the tire width direction.
In the range of 2W ≦ P1 ≦ 0.8W, the position P2 of the second torsion center axis is set at 0. 0 to the distance F (hereinafter referred to as sipe depth F) from the tread to the sipe bottom in the tire radial direction. Since the range is 2F ≦ P2 ≦ 0.6F, the rigidity of the small block is further increased as compared with the case where the first torsion center axis and the second torsion center axis are located outside the above range, and the small block falls down. Is suppressed (see FIGS. 24 and 25).

As described above, since the small blocks come into contact with a strong force due to the formation of the sipe by twisting,
In addition, since the rigidity of the small block can be increased by positioning the first torsion central axis and the second torsion central axis of the sipe within a predetermined range, it is possible to reliably prevent the small block from falling down. As a result, the contact area on the tread of the small block is increased, and the ice and snow performance is improved.

When the ground pressure acts on the tread of the block-shaped land portion, the block-shaped land portion is compressed in the height direction, guided by the sipe, and each small block is rotationally deformed in a direction in which the sipe is further twisted. Due to this deformation, a SAT (rotational moment for restoring the original shape) acting on each small block in a direction opposite to the twisting direction is generated.

Therefore, by forming a block-shaped land portion in which the sipes are twisted in an appropriate direction on the tread surface, the 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 caused by the code can be suppressed by the SAT generated in the block-shaped land portion.

According to the second aspect of the present invention, a plurality of reinforcing layers in which cords inclined at a predetermined angle with respect to the circumferential direction of the tire are arranged in parallel, and a tread provided above the stacked reinforcing layers; A pneumatic tire comprising: a main groove formed in 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 the main groove. , The sipe is a first convex portion convex in a first direction with respect to the virtual center plane,
A second convex portion that is convex in a second direction opposite to the first direction with the virtual center plane interposed therebetween, and has a shape that is exposed on the tread surface of the block-like land portion. And a bottom formed on the sipe bottom, wherein the virtual center plane is twisted from the surface to the bottom.

The operation of the second aspect of the present invention will be described.

Since the sipe has a structure twisted from the surface to the bottom, the block-shaped land portion is compressed in the height direction by the contact pressure and expands in the lateral direction, so that the sipe is divided by the sipe. Small blocks abut each other. In addition, since the sipe (virtual center plane) is twisted, the small blocks come into contact with each other not only by a force acting in the tire circumferential direction (tire rotation direction) but also by a force acting from another direction. Further, since the small blocks rotate by the contact pressure, the adjacent small blocks come into contact with each other with a strong force.

As described above, since the sipes are formed by twisting, the small blocks abut against each other with a strong force, so that the small blocks are reliably prevented from falling. As a result, the contact area on the tread of the small block is increased, and the ice and snow performance is improved.

In particular, since the sipe is not only twisted but also formed into a shape having irregularities sandwiching the first convex portion and the second convex portion, that is, the virtual center plane, the sipe is shaped like a block-like land by the ground pressure. Only by deforming the portion, the small blocks can be brought into stronger contact with each other and the contact area increases.
Therefore, the fall of the small block is further suppressed, the contact area on the tread is increased, and the ice and snow performance is further improved.

When the contact pressure acts on the tread surface of the block-shaped land portion, the height direction of the block-shaped land portion is compressed, guided by the sipe, and further reduced in a direction in which the sipe (virtual center plane) is further twisted. The block is deformed. With this deformation,
An SAT (rotational moment for restoring the original shape) in the direction opposite to the twisting direction is generated in each small block.

Therefore, by forming a block-shaped land portion in which the sipes are twisted in an appropriate direction on the tread surface, the 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 caused by the code can be suppressed by the SAT generated in the block-shaped land portion.

According to a third aspect of the present invention, in the second aspect of the present invention, the virtual center plane is twisted about a first torsion center axis extending in a tire radial direction in the block-shaped land portion. The position P1 of the first torsion center axis is within a range satisfying the following relational expression from one end face to the other end face of the block-shaped land portion in the tire width direction. It is characterized by the following.

0.2W ≦ P1 ≦ 0.8W Here, P1 is the position of the first torsion center axis, and W is the distance from one end surface of the block land portion to the other end surface in the tire width direction. ,.

The operation of the third aspect of the present invention will be described.

As described above, the sipes are formed in a shape in which the virtual center plane is twisted about the first torsion center axis extending in the tire radial direction. In this case, the position P1 of the first torsion center axis is set at 0. 0 with respect to the width W of the block-shaped land portion.
By being in the range of 2W ≦ P1 ≦ 0.8W, the rigidity is higher than that of the small block divided by the sipe in which the position P1 is out of the range (see FIG. 24). Therefore, the fall of the small block is further suppressed, the contact area on the tread is increased, and the ice and snow performance is further improved.

According to a fourth aspect of the present invention, in the second or third aspect, the virtual center plane is centered on a second torsion center axis extending substantially in the tire width direction in the block-shaped land portion. It has a twisted shape, and the position P2 of the second torsion center axis 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 torsion center axis, and F is the distance from the tread to the sipe bottom in the tire radial direction.

The operation of the invention will be described.

As described above, the sipes are formed in a shape in which the virtual center plane is twisted about the second torsion center axis extending substantially in the tire width direction. In this case, the position P2 of the second torsion center axis is 0.2F ≦ P with respect to the sipe depth F.
By being within the range of 2 ≦ 0.6F, the position P
2 is higher in rigidity than a small block divided by a sipe out of the range (see FIG. 25). Therefore, the fall of the small block is further suppressed, the contact area on the tread is increased, and the ice and snow performance is further improved.

According to the fifth aspect of the present 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, and a tread provided above the stacked reinforcing layers; A pneumatic tire comprising: a main groove formed in 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. The sipe has a closed loop shape not communicating with the main groove and the lug groove, and includes a surface portion exposed on a tread surface of the block-shaped land portion and a bottom portion formed on a sipe bottom; From the bottom to the bottom.

The operation of the fifth aspect of the present invention will be described.

Since the sipe has a structure twisted from the surface toward the bottom, the block-shaped land portion is compressed in the height direction by the contact pressure and swells in the lateral direction, thereby being divided by the sipe. Small blocks abut each other. In addition, since the sipes formed in the closed loop shape are twisted, the small blocks divided by the sipes are not only divided by the force acting in the tire circumferential direction (tire rotation direction) but also by the force acting in other directions. Abut In addition, because the small block performs rotary motion by the ground pressure,
Adjacent small blocks are brought into contact with a strong force.

As described above, since the sipes are formed by being twisted, the small blocks come into contact with each other with a strong force, so that the small blocks are reliably prevented from falling. As a result, the contact area on the tread of the small block increases, and the ice and snow performance is improved.

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 guided by the sipe and further deforms in a direction in which the sipe is further twisted. Due to this deformation, an SAT (rotational moment for restoring the original shape) in a direction opposite to the twisting direction is generated in the small block.

Therefore, by forming a block-shaped land portion in which the sipes are twisted in an appropriate direction on the tread surface, the 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 caused by the code can be suppressed by the SAT generated in the block-shaped land portion.

According to a sixth aspect of the present invention, in the first aspect of the present invention, the block-shaped land portion is twisted from a tread surface to a base portion. .

The operation of the invention according to claim 6 will be described.

Since not only the sipe but also the block land is twisted, the ground pressure increases the rotational force acting on the block land. As a result, the force for contacting adjacent small blocks in the block-like land portion,
Alternatively, the SAT (rotational moment to restore the original shape) of the small block is further increased, and the steering stability of the pneumatic tire is further increased.

According to a seventh aspect of the present invention, in the sixth aspect, the torsional direction of the block-shaped land portion is the same as the torsional direction from the tread surface of the sipe to the sipe bottom. It is characterized by.

The operation of the seventh aspect of the present invention will be described.

Since the torsional direction from the tread surface of the sipe to the sipe bottom is the same as the torsional direction of the block-shaped land portion, the rotation direction of the small block generated by the sipe due to the ground pressure and the block-shaped land portion The rotation directions of the block-shaped land portions generated by the twisting of the blocks coincide. Therefore, the SAT (rotational moment for restoring the original shape) generated at the block-shaped land portion is further increased, and the SAT generated by the cord is more easily suppressed. Thereby, steering stability is further improved.

According to an eighth aspect of the present invention, in the sixth aspect, the torsional direction of the block-shaped land portion is opposite to the torsional direction from the tread surface of the sipe to the sipe bottom. It is characterized by.

The operation of the invention will be described.

Since the torsional direction of the block-shaped land portion is opposite to the torsional direction from the tread surface of the sipe to the sipe bottom, the rotation direction of the block-shaped land portion generated by the torsion of the block-shaped land portion is different from that of the block-shaped land portion. Since the rotation directions of the small blocks generated by the torsion of the sipes 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 ice and snow performance is improved.

[0048]

[First Embodiment] A pneumatic tire according to a first embodiment of the present invention will be described with reference to FIGS.

As shown in FIG. 1, the tread 12 of the pneumatic tire 10 of the present embodiment has a tire circumferential direction (arrow A).
Direction, hereinafter referred to as A direction).
A plurality of blocks 18 defined by lug grooves 16 extending along the tire width direction (arrow B direction, hereinafter referred to as B direction) are formed.

Below the tread 12, the pneumatic tire 1
In order to secure a rigidity of 0, a reinforcing layer in which the steel cord 19 is arranged at a predetermined angle with respect to the A direction is laminated. On the outermost reinforcing layer closest to the surface of the tread 12, a steel cord 19 is disposed parallel to the A direction at a predetermined angle θ1 as shown in FIG.

As shown in FIG. 2, the block 18 is open to the side surfaces 20 and 22 in the direction B (opening on both sides).
A sipe 24 is formed.

The sipe 24 has a surface portion 28 which is straight on the tread surface 26 and a bottom portion 30 which is straight on the sipe bottom.
The surface portion 28 and the bottom portion 30 cross in an X-shape as shown in FIG.

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. A first side portion 32 and a second side portion 3
4 crosses the X shape.

That is, the sipe 24 passes from the tread surface 26 to the bottom portion 30 about a rotation axis Z perpendicular to the tread surface 26 while passing through a point where the surface portion 28 and the bottom portion 30 intersect in plan view. The shape is twisted toward the angle θ2.

Further, the sipe 24 passes through a point where the first side surface portion 32 and the second side surface portion 34 intersect with each other in a side view from the side surface 20 and has a rotation axis Y substantially parallel to the tread surface 26 as a center. The shape is twisted from the first side surface 32 toward the second side surface 34 by an angle θ12.

With the sipe 24 formed in this way, the block 18 is divided into small blocks 18a to 18 on the tread surface 26 side.
d.

The pneumatic tire 10 thus formed
The following operation can be obtained by mounting the vehicle on the vehicle.

A force perpendicular to the tread surface 26 acts on the tread surface 26 of the block 18 from the road surface. Thus, block 1
8 is compressed in the block height direction (arrow C direction, hereinafter referred to as C direction) and expands in the horizontal direction (A and B directions),
The small blocks facing each other across the sipe 24 are in contact with each other. At this time, since the sipe 24 is formed in a twisted shape, not only the force acting in the direction A, which is the tire rotation direction, due to the frictional force but also the adjacent small force due to the force in the direction B acting during cornering. The blocks abut each other.

The small blocks 18a to 18a-
Since 18d rotates clockwise in plan view from the tread surface 26 (see the solid arrow in FIG. 3), the adjacent small blocks come into contact with each other.

That is, since the sipes 24 are formed in a twisted shape, adjacent small blocks come into strong contact with each other by forces acting from various directions.

Thus, the small blocks 18a to 18d
Of the block 18 is greatly suppressed.
To increase the contact area and ensure good ice and snow performance.

The small blocks 18a to 18d described above
, Each of the small blocks 18a to 18d has a counterclockwise rotational moment (SA) for restoring the original shape.
T) occurs (see the dashed arrow in FIG. 3).

Therefore, the clockwise S generated by the steel cord 19 disposed in parallel with the outermost reinforcing layer.
AT (see arrow in FIG. 1) can be suppressed (reduced) by the counterclockwise SAT generated by each block 18.

The position P1 of the rotation axis Z in plan view from the tread surface 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, The same applies to the following). By positioning the rotation axis Z 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, ice and snow performance is further improved.

Further, the position P2 of the rotation axis Y in the side view from the side surface 20 is different from the tread surface 26 in the C direction from the bottom 3
0.2F ≦ P1 ≦ 0.6F toward 0 (sipe bottom)
(F is the vertical (C-direction) depth of the sipe 24; the same applies hereinafter). By positioning the rotation axis Y 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 down. As a result, ice and snow performance is further improved.

The size of the block 18 in the present embodiment is such that length L × width W × height H is 30 mm × 20 mm.
× 10 mm. The vertical depth F of the sipe 24 from the tread surface 26 is 8 mm. The sipe 24 is formed at a position where the distance a from the end face in the direction A of the block 18 and the distance a between adjacent sipes are 7 mm and the distance b to the other end face is 9 mm on the side surface 20. The distance b from the end face in the direction A of the block 18 on the side surface 22
Is 9 mm, the distance a between adjacent sipes, and the distance a to the other end face are 7 mm, and these end faces are connected by a straight line. The torsion angle θ2 of the sipe 24 is 11.4 °, and the torsion angle θ12 is 2
8.1 °. Second Embodiment Next, a pneumatic tire according to a second embodiment of the present invention will be described with reference to FIGS. Since only the sipe shape is different from the pneumatic tire of the first embodiment, only the sipe and the blade used to form the sipe will be described. Note that the same components as those in the first embodiment are denoted by the same reference numerals, and detailed description thereof will be omitted.

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 cross-sections in the D-direction, which are triangular protrusions having a height of 0.5 K, protrude alternately on both sides of the virtual center plane V at intervals J, and each protrusion 42 is orthogonal to the D-direction. Extending in the direction E. The blade 40 thus formed is
The virtual center plane V is disposed at the same position as the sipe 24 of the first embodiment, and the block is vulcanized in a mold.

When the sipe 44 of the block 18 formed by the blade 40 is viewed from the side 20, as shown in FIG.
4 are formed so as to be located at the same position as the sipe 24 of the first embodiment.

That is, when viewed from the side surface 20, the sipe 44 includes (the virtual center plane V of) the first side surface portion 46 on the side surface 20 and the second side surface portion 48 (on the side surface 22), as shown in FIG. Virtual center plane V) crosses the X-shape. Further, when viewed in plan from the tread surface 26, the sipe 44 is formed such that the virtual center plane V of the sipe 44 is located at the position of the sipe 24 in FIG.

Therefore, in substantially the same manner as the sipe 24 of the first embodiment, the virtual center plane V of the sipe 44 is a plane from the tread surface 26 toward the sipe bottom from the tread surface 26 around the rotation axis Z perpendicular to the tread surface 26. Only the angle θ2 is twisted when viewed (see FIG. 3).

The imaginary center plane V of the sipe 44 passes through a point where the imaginary center plane V of the side surface 20 and the side surface 22 intersects and a rotation axis Y substantially parallel to the tread surface 26 when viewed from the side surface 20. As a center, the shape is twisted by an angle θ12 from the side surface 20 toward the side surface 22 (see FIG. 5).

The sipe 44 is, as shown in FIG.
A first projection 45a projecting in a first direction with respect to the virtual center plane V corresponding to the projection 42 of the blade 40, and a second projection 45b projecting in a second direction opposite to the first direction. And

The pneumatic tire 10 thus formed
The following operation can be obtained by mounting the vehicle on the vehicle.

That is, similarly to the first embodiment, since the sipe 44 is formed by being twisted by the angle θ2, the adjacent small blocks can be connected to each other by the forces acting on the tread surface 26 of the block 18 from various directions. Contact with strong force.

Also, the small blocks 18a to 18a
Since 18d rotates clockwise in plan view from the tread surface 26 (see the solid arrow in FIG. 3), the adjacent small blocks come into contact with each other.

In particular, since the sipe 44 has an uneven portion whose AC cross section (a cross section cut along a plane formed by the directions A and C, the same applies hereinafter) is triangular, the small blocks 18a to 18a
Due to the compression in the direction C of 18d, the concave and convex surfaces of the adjacent small blocks with the sipe 44 interposed therebetween come into contact with a strong force.

As a result, the fall of the small blocks 18a to 18d is further suppressed, and the ice and snow performance can be further improved.

Further, similarly to the first embodiment, the sipe 44
Is twisted by an angle θ2 about the rotation axis Z, so that the small blocks 18a to 18d
Rotates clockwise when viewed from above.

By this rotation, each of the small blocks 18a-1
At 8d, a counterclockwise rotational moment (SAT) to be restored to the original shape is generated.

Therefore, the clockwise S generated by the steel cord 19 disposed in parallel with the outermost reinforcing layer.
AT (see arrow in FIG. 1) can be suppressed (reduced) by the counterclockwise SAT generated by each block 18.

By the way, as in the first embodiment, the position P1 of the rotation axis Z in plan view from the tread surface 26 is 0.2W ≦ P from the side surface 20 to the side surface 22 in the B direction.
It is preferable to be in the range of 1 ≦ 0.8W. The position P2 of the rotation axis Y in a side view from the side surface 20 is C
0.2F from the tread 26 toward the bottom 30 in the direction
It is preferable to be within the range of ≦ P2 ≦ 0.6F. By positioning the rotation axis Z and the rotation axis Y 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 down. As a result, ice and snow performance is further improved.

The size of the block 18 in this embodiment is 30 mm × 20 mm × 10 mm, as in the first embodiment, with a length L × width W × height H. Sipe 44
Has a vertical depth F from the tread surface 26 of 8 mm. Further, the sipe 44 is formed such that the virtual center plane V is located at a position where the distance a from the end face in the direction A of the block 18 and the distance a between adjacent sipes are 7 mm and the distance b to the other end face is 9 mm on the side surface 20. And the opposite side 22
The distance b from the end face in the direction A of the block 18 is 9 m
m, the distance a between adjacent sipes, and the distance a to the other end surface are formed at positions of 7 mm, and these end surfaces are connected by a straight line. The torsion angle θ2 of the sipe 44
Is 11.4 °, and the torsion angle θ12 is 28.1 °.

The sipe 44 has a shape in which the direction D of the virtual center plane V of the blade 40 coincides with the sipe depth direction and the direction E coincides with the sipe width direction. Therefore, Sipe 4
The interval and height of the triangular cross section of No. 4 are the same as the blade, the distance J between the vertices of adjacent triangles is 2 mm,
The height difference K between the vertices is 1 mm (the height 0.5K from the virtual center plane V is 0.5 mm). Third Embodiment Next, a pneumatic tire according to a third embodiment of the present invention will be described with reference to FIGS. Since only the sipe shape is different from the pneumatic tires of the first and second embodiments, only the sipe and the blade used to form the sipe will be described. Note that the same components as those in the first and second embodiments are denoted by the same reference numerals, and detailed description thereof will be omitted.

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 a triangular convex portion 52 having a height of 0.5 L in the cross section in the E direction alternately protrudes on both sides of the virtual center plane V at an interval M, and each convex portion 52 is formed in the E direction. And extends in the direction D orthogonal to. The blade 50 thus formed is disposed so that the virtual center plane V is formed at the same position as the sipe 24 of the first embodiment, and the block is vulcanized in a mold.

When the sipe 54 of the block 18 formed by the blade 50 is viewed from above the tread 26, the virtual center plane V is located at the same position as the sipe 24 of the first embodiment, as shown in FIG. It is provided to be. That is, when viewed in plan from the tread 26, as shown in FIG.
(The virtual center plane V) and the bottom 58 (the virtual center plane V) at the sipe bottom cross in an X-shape.

Also, when viewed from the side surface 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 surface 20 and the virtual center plane V on the side surface 22 cross in an X-shape.

Therefore, like the sipe 24 of the first embodiment, the sipe 54 passes through a point where the virtual center plane V of the surface portion 56 and the virtual center plane V of the bottom portion 58 intersect, and the tread 2
6 is twisted from the tread surface 26 toward the sipe bottom by an angle θ2 about a rotation axis Z perpendicular to 6.

When viewed from the side, the sipe 54
Are the virtual center plane V of the side surface 20 and the virtual center plane V of the side surface 22
And a rotation axis Y substantially parallel to the tread 26
From the side surface 20 to the side surface 22 with the angle θ1
It has a shape twisted by two.

The sipe 54 is, as shown in FIG.
A first projection 55a projecting in a first direction with respect to the virtual center plane V corresponding to the projection 52 of the blade 50, and a second projection 55b projecting in a second direction opposite to the first direction. And

The pneumatic tire 10 thus formed
The following operation can be obtained by mounting the vehicle on the vehicle.

That is, as in the first embodiment, since the sipe 54 is formed by being twisted by the angle θ2 in a plan view from the tread surface 26, not only the force acting from the A direction due to the frictional force but also the block 18 is formed. Of small blocks 18a to 18 by force from various directions acting from tread surface 26 of
d contact each other with a strong force. In particular, since the sipe 54 has an uneven 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. Uneven portions of adjacent small blocks are strongly engaged.

Therefore, the falling down of the small blocks 18a to 18d can be further suppressed, and the ice and snow performance can be further improved.

Further, similarly to the first embodiment, the sipe 54
Is twisted by an angle θ2 about the rotation axis Z, so that the small blocks 18a to 18d
6 in a plan view (see solid arrows in FIG. 7).

By this rotation, each of the small blocks 18a-1
At 8d, a counterclockwise rotational moment (SAT) to be restored to the original shape is generated (see the dashed arrow in FIG. 7).

Therefore, the clockwise S generated by the steel cord 19 disposed in parallel with the outermost reinforcing layer.
AT (see arrow in FIG. 1) can be suppressed (reduced) by the counterclockwise SAT generated by each block 18.

By the way, as in the first embodiment, the position P1 of the rotation axis Z in plan view from the tread surface 26 is 0.2W ≦ P from the side surface 20 to the side surface 22 in the B direction.
It is preferable to be in the range of 1 ≦ 0.8W. The position P2 of the rotation axis Y in a side view from the side surface 20 is C
In the direction, it is preferable to be in the range of 0.2F ≦ P2 ≦ 0.6F from the tread surface 26 toward the bottom (sipe bottom). By positioning the rotation axis Z and the rotation axis Y 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 down. As a result, ice and snow performance is further improved.

Note that the size of the block 18 in this embodiment is 30 mm × 20 mm × 10 mm, as in the first embodiment, length L × width W × height H. Sipe 54
Has a vertical depth F from the tread surface 26 of 8 mm. In addition, the sipe 54 is formed such that the virtual center plane V is located on the side surface 20 such that the distance a from the end face in the direction A of the block 18 and the distance a between adjacent sipes are 7 mm and the distance b to the other end face is 9 mm. And the opposite side 22
The distance b from the end face in the direction A of the block 18 is 9 m
m, the distance a between adjacent sipes, and the distance a to the other end surface are formed at positions of 7 mm, and these end surfaces are connected by a straight line. The torsion angle θ2 of the sipe 54
Is 11.4 °, and the torsion angle θ12 is 28.1 °.

The sipe 54 has a shape in which the direction D of the virtual center plane V of the blade 50 coincides with the sipe depth direction and the direction E coincides with the sipe width direction. Therefore, Sipe 5
4 is the same as 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 (the height from the virtual center plane V). 0.5L is 0.5 mm). [Fourth Embodiment] Next, a pneumatic tire according to a fourth embodiment of the present invention will be described with reference to FIG. First to first
Since only the sipe shape is different from the pneumatic tire of the third embodiment, the description of the blade used to form the sipe will be replaced with the description of the sipe shape. Note that the same components as those in the first to third embodiments are denoted by the same reference numerals, and detailed description thereof will be omitted.

As shown in FIG. 9, the blade 60 has convex portions 62 having a triangular cross section which alternately protrude on both sides of the virtual center plane V.
Is an arrow G inclined at a predetermined angle from both directions of the direction D and the direction E.
It is formed in a shape that is continuous in the direction.

The blade 60 has a triangular protrusion 6 having a height of 0.5 K in the cross section in the direction D, as in the second embodiment.
2 are formed in a zigzag shape that alternately protrudes on both sides of the virtual center plane V at an interval J. In addition, the blade 60
In the cross section in the direction, the height is 0.5 L as in the third embodiment.
Are formed on both sides of the virtual center plane V with the interval M
In a zigzag shape that protrudes alternately.

The blade 60 thus formed has the virtual center plane V disposed at the same position as the sipe 24 of the first embodiment, and the block is vulcanized in a mold.

The sipe (not shown) of the block 18 formed by the blade 60 has an imaginary center plane V of the first
It is provided so as to be located at the same position as the sipe 24 of the embodiment. Therefore, the virtual center plane V of the sipe has a shape that is 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). The virtual center plane V of the sipe is 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).

The pneumatic tire 10 thus formed
The following operation can be obtained by mounting the vehicle on the vehicle.

That is, similarly to the first embodiment, since the sipe is formed by being twisted by the angle θ2 when viewed from the tread surface 26, not only the force acting from the direction A but also the block 1 is formed.
The small blocks 18a to 18d are brought into contact with each other with a strong force by forces from various directions acting from the tread surface 26 of the block 8.

In particular, since the sipe has irregularities having a triangular cross section both in the sipe depth direction and in a plane parallel to the tread surface 26, the sipe is sandwiched by the compression of the small blocks 18a to 18d in the C direction. The uneven surface of the adjacent small block is brought into contact with a strong force, and the small block 1 caused by compression
Due to the rotational movement of 8a to 18d, the concave and convex portions of the adjacent small blocks are strongly engaged.

Therefore, the falling of the small blocks 18a to 18d can be further suppressed, and the ice and snow performance can be further improved.

Also, as in the first embodiment, the sipe has a shape twisted by an angle θ2 about the rotation axis Z, so that the small blocks 18a to 18d cause the treads 26 to be pressed by the ground pressure.
Rotates clockwise when viewed from above.

By this rotation, each of the small blocks 18a-1
At 8d, a counterclockwise rotational moment (SAT) to be restored to the original shape is generated.

Therefore, the clockwise S generated by the steel cord 19 disposed in parallel with the outermost reinforcing layer.
AT (see arrow in FIG. 1) can be suppressed (reduced) by the counterclockwise SAT generated by each block 18.

By the way, as in the first embodiment, the position P1 of the rotation axis Z in plan view from the tread surface 26 is 0.2W ≦ P from the side surface 20 to the side surface 22 in the B direction.
It is preferable to be in the range of 1 ≦ 0.8W. The position P2 of the rotation axis Y in a side view from the side surface 20 is C
In the direction, it is preferable to be in the range of 0.2F ≦ P2 ≦ 0.6F from the tread 26 to the bottom 30 (sipe bottom). By positioning the rotation axis Z and the rotation axis Y 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 down. As a result, ice and snow performance is further improved.

The size of the block 18 in the present embodiment is 30 mm × 20 mm × 10 mm, as in the first embodiment, with a length L × width W × height H. The vertical depth F from the tread surface 26 of the sipe is 8 mm. Further, the virtual center plane V has a distance a from the end face in the direction A of the block 18 on the side surface 20 and a distance a between adjacent sipes 7 m.
m, the sipe is formed such that the distance b to the other end surface is 9 mm, and the distance b from the end surface in the direction A of the block 18 is 9 mm on the opposite side surface 22, and the distance a between adjacent sipes a, And a distance a to the other end face is formed at a position of 7 mm, and the end faces are connected by a straight line. The sipe twist angle θ2 is 11.4 °.
And the torsion angle θ12 is 28.1 °.

The sipe has a shape in which the direction D of the virtual center plane V of the blade 60 coincides with the sipe depth direction, and the direction E coincides with the sipe width direction. Therefore, the interval and the height of the triangular cross section 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). 0.5K from the center plane V is 0.5 mm), the distance M between the vertices of adjacent triangles in the sipe depth direction is 1 mm, and the height difference L between the vertices is 1 mm (virtual center). 0.5 L from the surface V is 0.5 mm). Fifth Embodiment A pneumatic tire according to a fifth embodiment of the present invention will be described with reference to FIG. Since only the block shape and the sipe shape are different from the pneumatic tire of the first embodiment, only the block and the sipe will be described. Note that the same components as those in the first embodiment are denoted by the same reference numerals, and detailed description thereof will be omitted.

The block 70 has a shape rotated by an angle θ3 about the rotation axis U from the bottom surface 72 at the same height as the main groove 14 on the tread surface toward the tread surface 74 in a plan view from the tread surface 74. I have. That is, from the tread 74 to the bottom surface 7 around the rotation axis U perpendicular to the tread 74.
2, the shape is twisted counterclockwise by an angle θ3.

The sipe 7 provided in the block 70
6 also, the surface portion 78 that is a straight line on the tread surface 74 and the bottom portion 80 that is a straight line at the sipe bottom cross in an X-shape in plan view from the tread surface 74. That is, the sipe 76 also has the tread surface 74 centered on the rotation axis Z perpendicular to the tread surface 74.
, And twisted counterclockwise in the same direction as the block 18 by an angle θ4 toward the sipe bottom.

Further, in the sipe 76, a first side surface portion 75 that is straight on the side surface 71 and a second side surface portion 77 that is straight on the side surface 73 cross the X shape when viewed from the side surface 71. That is, the sipe 76 also has the first side surface 7 around the rotation axis Y (not shown) parallel to the tread surface 74.
5 to the second side surface 77 by an angle θ13 (not shown).

The pneumatic tire 10 thus formed
The following operation can be obtained by mounting the vehicle on the vehicle.

That is, similarly to the first embodiment, since the sipe 76 is formed by being twisted by the angle θ4, A
Not only the force acting from the direction but also the tread surface 74 of the block 70
Block 70 by force from various directions acting from
a to 70d are contacted with a strong force.

Further, since the sipes 76 and the blocks 70 are twisted in the same direction, the small blocks 70a to 70
d makes a clockwise rotational movement (see the solid arrow in FIG. 10) in plan view from the tread surface 74, and the adjacent small blocks come into contact with each other with a stronger force.

Therefore, it is possible to further suppress the small blocks 70a to 70d from falling down, and to further improve the ice and snow performance.

Further, similar to the first embodiment, the sipe 76
Has a shape twisted by an angle θ4 about the rotation axis Z, so that the small blocks 70a to 70d
(See solid arrows in FIG. 10) when viewed from above.

By this rotation, each of the small blocks 70a-7
At 0d, a counterclockwise rotational moment (SAT) to be restored to the original shape is generated (see the broken arrow in FIG. 10).

At the same time, since the block 70 is also twisted about the rotation axis U by the angle θ3, the block 70 is rotated clockwise in plan view from the tread surface 74 by the contact pressure (solid arrow in FIG. 10). reference).

With this rotation, a counterclockwise rotation moment (SA
T) occurs (see the thick broken line arrow in FIG. 10).

As described above, in the block 70 of the present embodiment, by forming the block 70 and the sipe 76 in a shape twisted in the same direction, a stronger SAT can be generated.

Therefore, the clockwise S generated by the steel cord 19 disposed in parallel with the outermost reinforcing layer.
AT (refer to the arrow in FIG. 1) is divided into block 70 and small block 70.
It can be suppressed (reduced) by the counterclockwise rotation moment generated by a to 70d.

By the way, as in the first embodiment, the position P1 of the rotation axis Z from the tread surface 74 in the plan view is 0.2W ≦ P from the side surface 20 to the side surface 22 in the B direction.
It is preferable to be in the range of 1 ≦ 0.8W. The position P2 of the rotation axis Y in a side view from the side surface 71 is C
0.2F from the tread 26 toward the bottom 30 in the direction
It is preferable to be within the range of ≦ P2 ≦ 0.6F. By positioning the rotation axis Z and the rotation axis Y 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 down. As a result, ice and snow performance is further improved.

The size of the block 70 in this embodiment is the same as that of the block 18 in the first embodiment.
X width W x height H is 30mm x 20mm x 10mm (Fig. 2
See). The vertical depth F from the tread surface 74 of the sipe is 8 mm. The torsional angle θ3 about the rotation axis U of the block 70 is 5 °.

The sipe 76 has a side surface 82 with a distance a from the end surface in the direction A of the block 70, a distance a between adjacent sipes 7 mm, and a distance b to the other end surface 9 m.
m, and the distance b from the A-direction end face of the block 70 on the opposite side surface 84 is 9 mm,
The distance a between adjacent sipes and the distance a to the other end surface are formed at positions of 7 mm, and the end surfaces are connected by a straight line. The torsion angle θ4 of the sipe 76 is 1
1.4 °, and the torsion angle θ13 is 28.1 °. Sixth Embodiment Next, a pneumatic tire according to a sixth embodiment of the present invention will be described with reference to FIG. Since only the block shape and the sipe shape are different from the pneumatic tire of the first embodiment, only the block and the sipe will be described. Note that the same components as those in the first embodiment are denoted by the same reference numerals, and detailed description thereof will be omitted.

The block 90 has a shape in which the block 90 is rotated by an angle θ5 from the bottom surface 92 at the same height as the main groove 14 to the tread surface 94 on the tread surface in plan view from the tread surface 94, as shown in FIG. ing. That is, it has a shape twisted clockwise by an angle θ5 from the tread surface 94 toward the bottom surface 92 about a rotation axis U perpendicular to the tread surface 94.

The sipe 9 provided in the block 90
6 also, the surface portion 98, which is straight on the tread surface 94, and the bottom portion 100, which is straight at the sipe bottom, cross in an X shape in plan view from the tread surface 94. That is, the sipe 96 also has the tread 9 around the rotation axis Z perpendicular to the tread 94.
The shape is twisted counterclockwise in the opposite direction from the block 18 by an angle θ6 from 4 toward the sipe bottom.

Further, in the sipe 96, a first side surface portion 95 that is straight on the side surface 91 and a second side surface portion 97 that is straight on the side surface 93 cross in an X shape when viewed from the side surface 91. That is, the sipe 96 also has the first side surface 9 around the rotation axis Y (not shown) parallel to the tread surface 94.
5 to the second side surface 97 by an angle θ14 (not shown).

The pneumatic tire 10 thus formed
The following operation can be obtained by mounting the vehicle on the vehicle.

That is, similar to the first embodiment, since the sipe 96 is formed by being twisted by the angle θ6, A
Not only the force acting from the direction but also the tread surface 94 of the block 90
Block 90 by force from various directions acting from
a to 90d are contacted with a strong force.

Further, since the sipes and the blocks are twisted in the opposite directions, the small blocks receive a rotational force in the opposite directions. As a result, adjacent small blocks abut very strongly.

Therefore, the falling down of the small blocks 90a to 90d can be further suppressed, and the ice and snow performance can be further improved.

As in the first embodiment, the sipe 96
Is twisted by an angle θ6 about the rotation axis Z, so that the small blocks 90a to 90d
4 rotates clockwise in a plan view (see solid arrows in FIG. 11).

By this rotation, each small block 90a-9
At 0d, a counterclockwise rotational moment (SAT) to be restored to the original shape is generated (see the broken arrow in FIG. 11).

At the same time, since the block 90 is also twisted about the rotation axis U by the angle θ5, the block 90 turns counterclockwise in plan view from the tread surface 94 due to the ground pressure (solid line in FIG. 11). Arrow)).

By this rotation, a clockwise rotational moment (SA
T) occurs.

Therefore, the difference between the rotational moments is the SAT generated in the block 90.

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 parallel to the outermost reinforcing layer can be removed from the block 90. And the SAT generated by the small blocks 90a to 90d can be suppressed (reduced).

By the way, as in the first embodiment, the position P1 of the rotation axis Z in plan view from the tread surface 94 is 0.2W ≦ P from the side surface 20 to the side surface 22 in the B direction.
It is preferable to be in the range of 1 ≦ 0.8W. Further, the position P2 of the rotation axis Y in a side view from the side surface 91 is C
0.2F from the tread 26 toward the bottom 30 in the direction
It is preferable to be within the range of ≦ P2 ≦ 0.6F. By positioning the rotation axis Z and the rotation axis Y 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 down. As a result, ice and snow performance is further improved.

It should be noted that the size of the block 90 in this embodiment is the same as the block 18 of the first embodiment, and the length L
X width W x height H is 30mm x 20mm x 10mm (Fig. 2
See). The vertical depth F from the tread surface 94 of the sipe is 8 mm. The torsional angle θ5 about the rotation axis U of the block 90 is 5 °.

The sipe 96 has a distance a from the end face in the direction A of the block 90 on the side face 102, a distance a between adjacent sipes 7 mm, and a distance b to the other end face 9 from the side.
mm and at the opposite side 104
The distance b from the end face in the direction A of the block 90 is 9 m
m, the distance a between adjacent sipes, and the distance a to the other end surface are formed at positions of 7 mm, and these end surfaces are connected by a straight line. Note that the torsion angle θ6 of the sipe 96 is
Is 11.4 °, and the torsion angle θ14 is 28.1 °. Seventh Embodiment Next, a pneumatic tire according to a seventh embodiment of the present invention will be described with reference to FIGS. Since only the sipe shape is different from the pneumatic tire of the first embodiment, only the sipe will be described. Note that the same components as those in the first embodiment are denoted by the same reference numerals, and detailed description thereof will be omitted.

Sipe 110 formed in block 18
Is a square closed loop whose AB cross section is a quadrangular shape. Bottom part 11
4 are connected continuously. That is, sipe 110
Has a shape twisted counterclockwise from the tread surface 26 toward the sipe bottom by an angle θ7 about a rotation axis Z perpendicular to the tread surface 26. The tread surface 26 side of the block 18 is divided by the sipe 110 into an inner small block 18e and an outer small block 18f.

The pneumatic tire 10 thus formed
The following operation can be obtained by mounting the vehicle on the vehicle.

The block 18 is compressed in the direction C by the contact pressure and expands in the directions A and B, whereby the sipe 1
Small blocks 18e and 18f opposed to each other across the block 10 come into contact with each other. At this time, since the small block 18e is guided by the sipe 110 and further deforms in the clockwise twisting direction, it comes into contact with the small block 18f with a strong force.

Accordingly, the small blocks 18e and 18f are prevented from falling down, and the contact area on the tread 26 is increased, thereby improving the ice and snow performance of the pneumatic tire 10.

Further, similarly to the first embodiment, the sipe 11
Since 0 is a shape twisted about the rotation axis Z by the angle θ7, the small block 18e rotates clockwise in plan view from the tread surface 26 due to the ground pressure (see the solid line arrow in FIG. 12).

With this rotation, the small block 18e
A counterclockwise rotational moment (SAT) is generated to restore the original shape (see the dashed arrow in FIG. 12).

Therefore, the clockwise S generated by the steel cord 19 disposed in parallel with the outermost reinforcing layer.
AT (see arrow in FIG. 1) can be suppressed (reduced) by the counterclockwise SAT generated by the small block 18e.

Note that the size of the block 18 in this embodiment is, as in the first embodiment, 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 is 8 mm.

The sipe 110 has a distance c from the A-direction end surface and the B-direction end surface of the block 18 on the tread surface 26.
Is formed at a position of 6 mm. The twist angle θ7 of the sipe 110 is 5 °. [Eighth Embodiment] Next, a pneumatic tire according to an eighth embodiment of the present invention will be described with reference to FIGS. Since only the block shape and the sipe shape are different from the pneumatic tire of the first embodiment, only the block and the sipe will be described. Note that the same components as those in the seventh embodiment are denoted by the same reference numerals, and detailed description thereof will be omitted.

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 from the bottom surface 122 in plan view are continuous. That is, from the tread surface 124 to the bottom surface 122 around a rotation axis U perpendicular to the tread surface 124.
The shape is twisted counterclockwise by an angle θ8 toward.

The closed loop sipe 126 provided in the block 120 and circling in a square shape is also provided on the tread surface 12.
4, the square surface portion 128 and the square bottom portion 130 having the same shape as the surface portion 128 at the sipe bottom are rotated by an angle θ9 in plan view from the tread surface 124. That is, the sipe 126 also has an angle θ9 counterclockwise in the same direction as the block 120 from the tread 124 toward the sipe bottom centering on the rotation axis Z perpendicular to the tread 124.
It has a rotated shape. In the present embodiment, the angle θ8 and the angle θ9 are the same, but may be different.

The tread surface 124 side of the block 120 is
The sipe 126 is divided into an inner small block 120e and an outer small block 120f.

The pneumatic tire 10 thus formed
The following operation can be obtained by mounting the vehicle on the vehicle.

The block 120 is compressed in the direction C and expanded in the directions A and B by the contact pressure, so that the small blocks 120e and 120f facing each other with the sipe 126 interposed therebetween.
Abuts.

Therefore, small blocks 120e, 120
The ice and snow performance of the pneumatic tire 10 is improved by suppressing the fall of f and increasing the contact area on the tread surface 124.

As in the first embodiment, the sipe 12
6 is twisted by an angle θ9 about the rotation axis Z, so that the small block 120e is
Rotate clockwise when viewed from above (see solid arrows in FIG. 14). Due to this rotation, a counterclockwise rotational moment (SAT) to be restored to the original shape is generated in the small block 120e (see a broken arrow in FIG. 14).

Furthermore, since the block 120 is twisted by the angle θ8 about the rotation axis U, the block 120 rotates clockwise in plan view from the tread surface 124 due to the ground contact pressure (see the solid line arrow in FIG. 14). .

This rotation causes the block 120 to have a counterclockwise rotation moment (S
AT) (see the bold dashed arrow in FIG. 14).

As described above, in the block 120, since the rotation moment (SAT) generated by the torsion of the block 120 itself and the torsion of the sipe 126 are in the same direction, a stronger SAT is generated.

Therefore, the clockwise S generated by the steel cord 19 disposed in parallel with the outermost reinforcing layer.
AT (see arrow in FIG. 1) can be more strongly suppressed (reduced) by the counterclockwise SAT generated by the block 120.

Note that the size of the block 120 in this embodiment is 30 mm × 20 mm × 10 mm, as in the first embodiment, length L × width W × height H. The vertical depth F of the sipe 126 from the tread surface 124 is 8 mm. The torsional angle θ8 about the rotation axis U of the block 120 is 5 °.

Further, on the tread 124, the block 12
The distance c from the end surface A in the direction A and the end surface in the direction B to the sipe 126 is 6 mm. The torsion angle θ9 about the rotation axis Z of the sipe 126 is 5 °. [Ninth Embodiment] Finally, a pneumatic tire according to a ninth embodiment of the present invention will be described with reference to FIGS. Since only the block shape and the sipe shape are different from the pneumatic tire of the first embodiment, only the block and the sipe will be described. Note that the same components as those in the seventh and eighth embodiments are denoted by the same reference numerals, and detailed description thereof will be omitted.

The block 140 has a tread surface 1 at a position rotated by an angle θ10 with respect to the bottom surface 142 in plan view and the bottom surface 142 at the same height as the main groove 14 on the tread surface.
44 and a continuous shape. That is, tread 1
It has a shape twisted counterclockwise from the tread surface 144 toward the bottom surface 142 by an angle θ10 about a rotation axis U perpendicular to 44.

The closed loop sipe 146 provided in the block 140 is also a square loop.
4 and the bottom 150 which is the sipe bottom are rotated clockwise by an angle θ11 in a plan view from the tread surface 144. That is, the sipe 146 also has the tread 144
Is rotated clockwise by an angle θ11 in the opposite direction to the block 140 from the tread surface 144 toward the sipe bottom about a rotation axis Z perpendicular to the center.

The tread 144 side of the block 140 is
The sipe 146 divides the inner small block 140e and the outer small block 140f.

The pneumatic tire 10 thus formed
The following operation can be obtained by mounting the vehicle on the vehicle.

The block 140 is compressed in the direction C and expanded in the directions A and B by the contact pressure, so that the small blocks 140e and 140f facing each other with the sipe 146 interposed therebetween.
Abuts. At this time, the small block 140e tries to rotate counterclockwise due to the ground pressure, and the small block 140e
Since f tries to rotate clockwise due to the torsion of the block 140, the small blocks 140e and 140f adjacent to each other with the sipe 146 interposed therebetween come into contact with a stronger force.

Therefore, small blocks 140e, 140
The fall of f is further suppressed, and the snow contact performance of the pneumatic tire 10 is improved by increasing the contact area on the tread 144.

Further, similarly to the first embodiment, the sipe 14
6 is twisted by an angle θ11 about the rotation axis Z, so that the small block 140 e
4 rotates counterclockwise in plan view (FIG. 16
See solid arrow). By this rotation, the small block 140e
, A clockwise rotational moment (SAT) to be restored to the original shape is generated (see the dashed arrow in FIG. 16).

On the other hand, since the block 140 has a shape twisted about the rotation axis U by the angle θ10, the block 140 rotates clockwise in plan view from the tread 144 due to the contact pressure (see the solid arrow in FIG. 16). .

By this rotation, a counterclockwise rotation moment (S
AT) (see the thick broken line arrow in FIG. 16).

Therefore, the rotational moment (SAT) generated by the entire block 140 is the difference between the rotational moment (SAT) generated by the torsion of the block 140 itself and the torsion of the sipes 146.

Therefore, by disposing the block 140 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 parallel to the outermost reinforcing layer can be removed from the block 140. Can be suppressed (reduced) by the SAT generated.

The size of the block 140 in the present embodiment is 30 mm × 20 mm × 10 mm, as in the first embodiment, with a length L × width W × height H. The vertical depth F from the tread surface 144 of the sipe is 8 mm. The torsional angle θ10 about the rotation axis U of the block 140 is 5 °.

The sipe 146 is formed on the tread surface 144 at a position where the distance c from the end surface in the direction A and the end surface in the direction B of the block 140 is 6 mm. The torsion angle θ11 about the rotation axis Z of the sipe 146 is 5 °.

The angle θ10 and the angle θ11 may be the same or different. [Test Example] Next, S performed using a sample block
Tests of the AT and the amount of block deformation and a test of braking performance on ice performed using actual tires will be described with reference to FIGS.

First, the SAT test will be described. The sample block corresponds to a pneumatic tire block. Examples 1 to 9 are blocks of the first to ninth embodiments, respectively.

The block 18 of the comparative example 1 includes FIG.
As shown in FIG. 8, the sipe depth direction is C
A sipe 152 formed in a straight line parallel to the direction is provided. The size of the block 18 is 30 mm in length L × width W × height H, similarly to the block 18 of the first embodiment.
X 20 mm x 10 mm. Tread surface 26 of sipe 152
Is 8 mm. Also, the side surfaces 20, 2
2, the distance f from the end face in the direction A of the block 18 is 8 mm, and the distance g between adjacent sipes is 7
mm.

Further, in Comparative Example 2, as shown in FIG.
This is a block 18 in which a sipe 162 that is a square closed loop is formed. The size is the size of the block 18 of the seventh embodiment.
Similarly, 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 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.

There is no twisted portion in any of the blocks of Comparative Example 1 and Comparative Example 2.

In Examples 1 to 9 and Comparative Example 1,
2 shows the SAT when the second block is pressed perpendicular to the road surface and compressed to 10% of the block height. FIG. 20 shows the test results. The unit is kgf
M. Here, when viewed from the tread surface in a plan view, the counterclockwise direction is +, and the clockwise direction is-.

When Examples 1 to 6 are compared with Comparative Example 1, it can be seen that the small block is rotated by the ground pressure and the SAT is generated because the sipes are twisted.
In Examples 1 to 4, the effect of providing the sipe with irregularities having a triangular cross section was slight, and it can be seen that the torsion greatly affected the SAT.

In addition, comparing Example 5 and Example 6 in which the sipe and the block are twisted, Example 5 in which the sipe and the block are twisted in the same direction is the case where the sipe and the block are twisted in the opposite direction. It can be seen that an SAT larger in absolute value than in the twisted Example 6 is generated.

When Examples 7 to 9 are compared with Comparative Example 2, it can be seen that the small blocks are rotated by the ground pressure and the SAT is generated because the sipes are twisted.
In particular, in the eighth and ninth embodiments in which the block is also twisted,
It can be seen that in Example 8 in which the sipes and the blocks were twisted in the same direction, a very large SAT was generated.

Next, a test for examining the amount of deformation was performed using the same sample block. Load the block on ice 2.2
pressing in kgf / cm ^2, was examined A direction displacement at the tread end portion of the sample blocks in a state where the ice against the sample block are relatively moved at a speed of 20 km / h. The test results are shown in FIG. The unit is mm.

When Examples 1 to 6 are compared with Comparative Example 1, the small blocks are rotated by the contact pressure and strongly contact each other due to the twisting of the sipes. It turns out that it is suppressing. Examples 1-4
In Examples 2 to 4 in which the sipe is provided with irregularities having a triangular cross section, the amount of deformation is further suppressed, and in particular, Examples 3 and 4 in which the sipe is formed so as to mesh with the rotational deformation of the small block fall ( (Deformation amount) is further suppressed.

In the fifth and sixth embodiments in which the block is also torsioned, the sixth embodiment in which the sipe and the block are torsioned in directions opposite to each other applies a small rotational force to the sipe and the block. Since the blocks come into strong contact with each other, the fall (the amount of deformation) is more effectively suppressed.

When Examples 7 to 9 are compared with Comparative Example 2, since the sipes are twisted, the small blocks rotate due to the ground pressure and come into contact with the adjacent small blocks, so that the fall (the amount of deformation) is suppressed. You can see that it is doing. In particular, in the eighth and ninth embodiments in which the block is also twisted, the ninth embodiment in which the sipe and the block are twisted in opposite directions is strongly contacted by the small blocks. Volume) is better controlled.

Subsequently, a brake performance test on ice was performed by mounting a pneumatic tire on an actual vehicle. Tire size is 1
85 / 70R14. The tires of Examples 1 to 9 and Comparative Examples 1 and 2 used in a series of tests are pneumatic in which blocks having the same shape as the sample blocks of Examples 1 to 9 and Comparative Examples 1 and 2 are formed on the tread surface. Tires.

In the brake test on ice, a tire is mounted on a vehicle, and a sudden brake is applied while traveling on an icy road at a speed of 20 km / h to measure a braking distance. The test results show the braking performance on ice using the reciprocal of the braking distance as an index. A larger index indicates better braking performance on ice. FIG. 22 shows the test results. The brake performance on ice of Comparative Example 1 is set to 100.

As for the brake performance on ice, the brake performance on ice is better in Examples 1 to 9 as compared with the comparative example.

Next, in the block 70 of the fifth embodiment, the torsional angle θ3 of the block and the torsional angle θ4 of the sipe
Was used as the same angle, and the relationship between the torsion angle and the amount of deformation was examined using several sample blocks in which the angle θ3 (= θ4) was changed. The results are shown in the graph of FIG.

As described above, the torsion angles θ3, θ
4 increases, the displacement decreases. That is, as the torsional angles θ3 and θ4 increase, the falling of the block can be further suppressed. However, if the torsion angle is too large when removing the block from the mold in the manufacturing process, the block will be chipped. From this manufacturing limit, it is preferable that the torsional angles θ3 and θ4 of the block and the sipe satisfy 0 ° <θ3 (= θ4) ≦ 50 °.

Further, a test was conducted on the relationship between the position of the rotation axis Z corresponding to the first torsional rotation axis and the rigidity of the small block.

The sample blocks are substantially the same as those of the first embodiment shown in FIG. 2, and a plurality of sample blocks having rotation axes Z at different positions in the direction of arrow B are prepared. That is, the small blocks 18a to 18d with respect to the position of the rotation axis Z
The change in the amount of displacement in the A direction was examined. In the test, the amount of displacement of the sample block in the direction A at the tread edge was examined with the block pressed against ice at a load of 2.2 kgf / cm ² and the ice moved relative to the sample block at a speed of 20 km / h.

The test results are shown in FIG. Here, the horizontal axis indicates the position of the rotation axis Z in the B direction in the block 18, and the numeral indicates the distance from the side surface 20 as a percentage with respect to the width W. The vertical axis represents the reciprocal of the amount of displacement of the small block in the A direction when the rotation axis Z is positioned on the side surface 20.
The stiffness ratio when 0 is set is shown.

As shown in FIG. 24, the position (P
In 1), the rigidity of the small block was further increased in the range of 20% to 80% of the width W (0.2W ≦ P1 ≦ 0.8W), and it was confirmed that the small block was further prevented from falling down.

Next, the relationship between the position of the rotation axis Y corresponding to the second torsional rotation axis and the rigidity of the small block was examined.

The sample blocks are substantially the same as those of the first embodiment shown in FIG. 2, and a plurality of sample blocks in which the rotation axis Y is located at different positions in the direction of arrow C are prepared. That is, the small blocks 18a to 18d with respect to the position of the rotation axis Y
The change in the amount of displacement in the A direction was examined. In the test, the amount of displacement of the sample block in the direction A at the tread edge was examined with the block pressed against ice at a load of 2.2 kgf / cm ² and the ice moved relative to the sample block at a speed of 20 km / h.

FIG. 25 shows the test results. Here, the horizontal axis represents the position of the rotation axis Z in the C direction in the block 18, and the numeral represents the distance from the tread surface 26 as a percentage of the vertical depth F of the sipe 24. The vertical axis is the rotation axis Y
Shows the stiffness ratio when the reciprocal of the amount of displacement of the small block in the direction A is set to 100 when is positioned on the tread surface 26.

As shown in FIG. 25, the position (P
2) is 20% to 6% of the vertical depth F of the sipe 24
In the range of 0% (0.2F ≦ P2 ≦ 0.6F), the rigidity of the small block was further increased, and it was confirmed that the small block was further prevented from falling down.

In the above two tests, only the results of tests performed on sample blocks substantially similar to those in the first embodiment are shown. However, the above two tests are also performed on sample blocks substantially similar to those in the second to sixth embodiments. Similar test results were obtained.

[0207]

As described above, the present invention has the above-described structure, so that the falling of the block is suppressed to ensure good ice and snow performance, and the SAT generated by the arrangement direction of the cords of the reinforcing layer closest to the tread surface is favorably reduced. Can be suppressed. As a result, a vehicle equipped with such a pneumatic tire can obtain good steering stability.

[Brief description of the drawings]

FIG. 1 is a plan view of a tread of a pneumatic tire according to the present invention.

FIG. 2 is a perspective view of a block according to the first embodiment of the present invention.

FIG. 3 is a plan view of a block according to the first embodiment of the present invention.

FIG. 4 is a side view of the block according to the first embodiment of the present invention.

FIG. 5 is a side view of a block according to a second embodiment of the present invention.

FIG. 6 is an explanatory view of a blade shape according to a second embodiment of the present invention.

FIG. 7 is a plan view of a block according to a third embodiment of the present invention.

FIG. 8 is an explanatory diagram of a blade shape according to a third embodiment of the present invention.

FIG. 9 is an explanatory diagram of a blade shape according to a fourth embodiment of the present invention.

FIG. 10 is a plan view of a block according to a fifth embodiment of the present invention.

FIG. 11 is a plan view of a block according to a sixth embodiment of the present invention.

FIG. 12 is a plan view of a block according to a seventh embodiment of the present invention.

FIG. 13 is a side view of a block according to a seventh embodiment of the present invention.

FIG. 14 is a plan view of a block according to an eighth embodiment of the present invention.

FIG. 15 is a side view of a block according to an eighth embodiment of the present invention.

FIG. 16 is a plan view of a block according to a ninth embodiment of the present invention.

FIG. 17 is a side view of a block according to a ninth embodiment of the present invention.

FIG. 18 is a perspective view of a block according to Comparative Example 1.

FIG. 19 is a perspective view of a block according to Comparative Example 2.

FIG. 20 is a view 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 a brake performance test on ice.

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 the rotation axis and the rigidity of the small block.

FIG. 25 is a graph showing the relationship between the position of the rotation axis and the rigidity of the small block.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 10 Pneumatic tire 12 Tread 14 Main groove 16 Lug groove 18 Block (block-shaped land part) 19 Steel cord 24 Sipe 26 Tread surface 28 Surface part 30 Bottom Z Rotation axis (first torsion center axis) Y Rotation axis (second axis) Center axis of torsion)

Claims (8)

[Claims] 1. A plurality of reinforcing layers in which cords inclined at a predetermined angle with respect to a tire circumferential direction are arranged in parallel, a tread provided on an upper portion of the stacked reinforcing layers, A main groove formed in a direction, and a sipe-containing block-shaped land portion partitioned by a lug groove formed in a direction intersecting with the main groove, a pneumatic tire comprising: The first torsion central axis extending in the tire radial direction and the second torsion central axis extending substantially in the tire width direction at the land portion; The position P1 of the second torsion center axis is between the one end surface and the other end surface of the block-shaped land portion in the tire width direction.
2. A pneumatic tire, wherein the number 2 is within a range satisfying the following relational expression from the tread surface to the sipe bottom in the tire radial direction. 0.2W ≦ P1 ≦ 0.8W 0.2F ≦ P2 ≦ 0.6F Here, P1 and P2 are the positions of the first and second torsion center axes, respectively, and W is the tire in the block-shaped land portion. F is a distance from one tread to the other end in the width direction, and F is a distance from the tread to the sipe bottom in the tire radial direction. 2. 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 stacked reinforcing layers, and a tire circumferential surface on the tread surface. And a block-shaped land portion with a sipe defined by a main groove formed in a direction, and a lug groove formed in a direction intersecting the main groove, wherein the sipe has a virtual center. A first convex portion that is convex in a first direction with respect to the surface, and a second convex portion that is convex in a second direction opposite to the first direction across the virtual center plane. A surface portion exposed on the tread surface of the block-shaped land portion and a bottom portion formed on the sipe bottom, wherein the virtual center plane is twisted from the surface portion toward the bottom portion. Features pneumatic tires. 3. The virtual center plane is shaped to be 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 is provided. The pneumatic tire according to claim 2, wherein the position P1 is within a range satisfying the following relational expression from one end surface of the block-shaped land portion to the other end surface in the tire width direction. 0.2W ≦ P1 ≦ 0.8W Here, P1 is the position of the first torsion center axis, and W is the distance from one end face to the other end face of the block-shaped land portion in the tire width direction. . 4. The virtual center plane has a shape twisted about a second torsion center axis extending substantially in the tire width direction in the block-shaped land portion, and the second torsion center is provided. 4. The pneumatic tire according to claim 2, wherein the shaft position P <b> 2 is within a range satisfying the following relational expression from the tread surface to the sipe bottom in the tire radial direction. 5. 0.2F ≦ P2 ≦ 0.6F Here, P2 is the position of the second torsion center axis, and F is the distance from the tread to the sipe bottom in the tire radial direction. 5. 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 stacked reinforcing layers, and a tire circumference on the tread surface. A main groove formed in a direction, and a sipe-containing block-shaped land portion partitioned by a lug groove formed in a direction intersecting the main groove, a pneumatic tire comprising: A closed loop shape not communicating with the groove and 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,
A pneumatic tire being twisted from the surface to the bottom. 6. The block-shaped land portion is twisted from a tread surface to a base portion.
The pneumatic tire according to any one of claims 1 to 4. 7. The pneumatic tire according to claim 6, wherein the torsional direction of the block-shaped land portion is the same as the torsional direction from the tread surface of the sipe to the sipe bottom. 8. The pneumatic tire according to claim 6, wherein the torsional direction of the block-shaped land portion is opposite to the torsional direction from the tread surface of the sipe toward the sipe bottom.