JP6706150B2 - tire - Google Patents

Description

The present invention relates to a tire having a 3D sipe formed on a tire tread side of a tread land portion, and particularly to a tire having excellent on-ice performance.

Conventionally, as a tread pattern of a studless tire, in order to improve on-ice performance, a lug groove extending in a direction intersecting with the circumferential groove is provided, and a tire width direction is provided on a surface of a block defined by the circumferential groove and the lug groove. Many are used to form a sipe that extends to.
However, with the above configuration, although the on-ice performance is improved, the blocks are subdivided by sipes, so that the block rigidity is reduced, and as a result, the grounding property may be reduced.
Therefore, a method has been proposed in which the sipe is a 3D sipe whose shape is changed not only on the tire tread side but also in the tire radial direction to improve the sipe contact force and suppress a decrease in block rigidity (for example, , Patent Document 1).

JP 2008-49971 A

By the way, since the 3D sipe has a shape that bends in the depth direction, the pull-out resistance when pulling out the vulcanized tire from the mold is large, and as a result, a large pull-out force is required. When the pulling-out force becomes large, there arises a problem that the bent portion of the sipe is widened and a defective shape is likely to occur.
The present invention has been made in view of the conventional problems, and provides a tire including a 3D sipe that can secure the sipe contact force at the time of input and can reduce the pull-out force when the vulcanization kettle is pulled out. To aim.

The present invention is a tire having a sipe that opens on the tread surface of a tread portion, and has a sipe that opens on the tread surface of a land portion formed in the tread portion by a groove extending in the tire circumferential direction and the tire width direction. In the tire, the sipe has two shapes on one side and one on the other side by being alternately provided while being inverted to one side and the other side with the center line in the extending direction of the sipe sandwiched therebetween in a shape that opens on the tread surface. The trapezoidal wavy portion and the straight portion that linearly extends from both ends of the trapezoidal wavy portion along the center line in the extending direction and that opens to the groove wall that forms the land portion. of the shape when viewed in cross section by a plane perpendicular to the continuous direction, one end opening to the tread surface, and the first sipe portion extending linearly toward the inner side in the tire radial direction, of the first support type unit located on the inner side in the tire radial direction, and a second sub type portion extending in a straight line or an arc shape toward the inner side in the tire radial direction, and sipes outermost is an end open to the tread surface of the first sipe portion , the extending direction of the sipe centerline and the first sub type portion is a straight line connecting the sipe innermost a tire radial direction inner end portion of the second sipe portion, both inclined with respect to the tire radial direction And the inclination angles thereof are opposite to each other , one end of the second sipe portion is located directly at the end portion of the first sipe portion on the inner side in the tire radial direction, or the center of curvature is located on the sipe center line side. It is characterized in that it is connected via an arcuate bent portion and is inclined with respect to the extension direction of the first sipe portion .
In this way, the distance between the wall surfaces of the sipe is made constant, and the sipe center line and the extension direction of the first sipe portion are inclined in directions opposite to each other with respect to the tire radial direction. It is possible to reduce the pull-out force at the time of pulling out and to increase the sipe contact force at the time of input.
Further, the size of the centerline inclination angle, which is the angle formed by the sipe centerline of the sipe and the tire radial direction, is defined by the first sipe inclination angle, which is the angle formed by the extension direction of the first sipe portion and the tire radial direction. By making the size larger than the size, the inclination of the sipe on the tire radial direction inner side can be made smaller, so that the pull-out force when the vulcanizer is pulled out can be further reduced.
Further, since the size of the first sipe inclination angle is in the range of 60 degrees to 90 degrees and the size of the centerline inclination angle is in the range of 60 degrees to 90 degrees, the vulcanization kettle pull-out characteristic and the sipe at the time of input The contact force can be increased together.
Further, in the present invention, the width w2 of the second sipe portion in the direction perpendicular to the tire radial direction in the plane perpendicular to the extension direction of the sipe on the tread surface is such that the width of the sipe on the tread surface of the first sipe portion is It is characterized by being at least twice the width w1 in the direction perpendicular to the tire radial direction in the plane perpendicular to the extension direction.
With this, the width of the second amplitude can be made appropriate, so that the pulling force when the vulcanization kettle is pulled out can be reduced while securing the contact force of the 3D sipe.
When the extension direction on the tire tread surface of the sipe is the tire width direction, the width w1 and the width w2 are the width in the tire circumferential direction, and when the extension direction is the tire circumferential direction, the width w1 and the width w2 are the tire width. Refers to the width in the direction.
Further, the present invention, the second sub type unit, when connected to the first sipe portion via a bent portion, a circular arc shape having a radius of curvature larger than the radius of curvature of the bent portion, or the radius of curvature tire larger as it goes radially inward, and consists curve center of curvature is on one side of all the sipe centerline, the center of curvature of the center of curvature and the bending curve portion of the second sipe portion, across the service type Characterized by being on opposite sides of each other.
As described above, the center of curvature is opposite to the center of curvature of the second sipe portion between the first sipe portion located on the opening end side of the sipe and the second sipe portion located on the inner side in the tire radial direction. Since the second sipe portion has a curved line with a large radius of curvature while the bent portion on the side is provided, the sipe contact force is secured, the contact force at the time of input is secured, and the pull-out force when the vulcanizer is pulled out. Can be reduced.

It is a figure which shows one Embodiment of the tread pattern of a tire. It is a principal part perspective view of a tread. It is a figure which shows the detail of a sipe shape. It is a figure which shows the example of arrangement|positioning of a sipe. It is a principal part sectional drawing of a vulcanization mold. It is a figure for demonstrating the hook pull-out characteristic of sipe formation at the time of tire molding. It is a figure for explaining operation of Sipe at the time of input. It is a figure which shows the other example of arrangement|positioning of a sipe. It is a figure which shows the other example of arrangement|positioning of a sipe. It is a figure which shows the other example of arrangement|positioning of a sipe. It is a figure which shows the other example of a sipe. It is a principal part perspective view of the tread which concerns on other embodiment. It is a figure which shows the detail of the sipe shape which concerns on other embodiment. It is a figure for demonstrating the detail of a sipe shape. It is a figure which shows the example of arrangement|positioning of a sipe. It is a principal part sectional drawing of a vulcanization mold. It is a figure for demonstrating the vulcanization kettle pull-out characteristic of the tire of this invention. It is a figure for explaining operation of Sipe at the time of input. It is a figure which shows the other shape of the sipe by this invention. It is a figure which shows the other example of arrangement|positioning of a sipe. It is a figure which shows the other example of arrangement|positioning of a sipe. It is a figure which shows the other example of arrangement|positioning of a sipe. It is a figure which shows the other example of a sipe.

Hereinafter, the present invention will be described in detail through embodiments of the invention, but the following embodiments do not limit the invention according to the claims, and all combinations of the features described in the embodiments are the inventions. It is not always essential to the solving means, and includes configurations that are selectively adopted.

Hereinafter, embodiments of the present invention will be described with reference to the drawings.
FIG. 1 is a diagram showing an example of a tread pattern of a tire 10 according to the present embodiment, and FIG. 2 is a perspective view of a main part of a tread 11.
The tread 11 includes a circumferential groove 12 formed so as to extend along the tire circumferential direction, a lateral groove 13 extending along a direction intersecting with the circumferential groove 12, a circumferential groove 12 and the lateral groove 13. A plurality of divided blocks 14 and sipes 15 formed on the tire tread side of each block 14 are provided. Note that the reference numeral CL in FIG. 1 is a center line indicating the center of the tire 10 in the width direction. Further, in the following description, dimensions such as the length and angle of each part are defined by the center plane of the groove width of the sipe 15. The center plane of the sipe 15 in a plan view or a sectional view is shown as a center line 15x, and dimensions such as length and angle of each part are defined based on this.
The sipe 15 is a 3D sipe that extends in a direction parallel to the tire width direction on the surface of the block 14 (the tread surface 14k), and has a shape changed in the tire radial direction in a plane perpendicular to the tire width direction.
The surface shape of the tread surface 14k of the sipe 15 may be a straight line parallel to the tire width direction, but in this example, as shown in FIG. 1, the straight line portion 15m parallel to the tire width direction and the tire width direction are parallel to each other. A trapezoidal wave shape is provided by having an inclined portion 15n that inclines with respect to each other and alternately providing a linear portion 15m and an inclined portion 15n.

Specifically, as shown in the enlarged view of FIG. 1, in the shape of the sipe 15 that is open to the tread surface 14k, one end side is located on the extension direction center line c of the sipe 15, and the extension direction center line c A first inclined section 31 that extends in a direction away from the first inclined section 31 and one end side of which is connected to the other end side of the first inclined section 31, and is separated by a predetermined distance in the direction along the extending direction center line c, for example, in a linear shape. A second extension extending from the extension section center line c at an angle θ at which one end side is connected to the other end side of the extension section 32 and the first inclined section 31 intersects the extension section 32. The inclined section 33 has a basic shape, and the basic shape is alternately provided while being inverted with the extension direction center line c interposed therebetween, thereby forming a trapezoidal wave shape. The extending direction center line c is a center line of a wave height that swings in a direction intersecting with the extending direction of the sipe 15 when the tread surface 14k is viewed in a plan view. Further, the term “inclined and extended” includes a vertical angle, an acute angle, and an obtuse angle, except for those parallel to the extending direction of the sipe 15. Further, the direction along the extension direction center line c includes a direction parallel to the center line c or a direction toward the extension direction center line c as an inclination angle of ±20 degrees. Further, none of the first inclined section 31, the second inclined section 33, and the separated section 32 is limited to a straight line, and may have a curved curvature.
Further, an extension portion 34, which is continuous with the first inclined section 31 and the second inclined section 33 and extends linearly along the extending direction center line c, is provided at the end portion in the extending direction. Then, the extension portion 34 opens to the groove wall that partitions the block 14.
The sipe 15 has a single cycle length L1 in which the section length along the extending direction center line c of the first inclined section 31, the separated section 32, and the second inclined section 33 is a half cycle when the tread surface 14k is viewed in plan view. Of the first sloping section 31, the separation section 32, the second sloping section 33, the first sloping section 31, the separation section 32, and the second sloping section 33 of the sipe extending direction in each section 31, 32, 33. It is the shortest dimension and is set in the range of 0.8 times to 2.0 times the groove depth D (see FIG. 3) of the sipe 15. It is preferable to set in the range of 1.08 times to 1.64 times.

In addition, the wave height of the sipe 15, which is the dimension in the direction orthogonal to the extending direction center line c of the separated sections 32, 32 located on both sides of the extending direction center line c, is the same as that of the sipe 15 formed in the trapezoidal wave shape. It is a dimension in which the length in the perpendicular direction from the extending direction center line c which is the amplitude A to the spacing section 32 is doubled, and is set in the range of 0.2 times to 2.0 times the groove depth D. It It is preferable to set it in the range of 0.3 times to 1.0 times.
The length L3 of the separation section 32 along the extending direction center line c is set in the range of 0.15 to 0.4 times the groove depth D. It is preferable to set it in the range of 0.2 times to 0.35 times.
The length L3 is set in the range of 0.12 times to 0.28 times the one cycle length L1. It is preferable to set it in the range of 0.16 times to 0.24 times.
The length L2 along the extending direction center line c of the first inclined section 31 and the second inclined section 33 is set in the range of 0.2 to 0.6 times the groove depth D. It is preferable to set it in the range of 0.3 times to 0.5 times.
The length L3 is set in the range of 0.35 to 0.94 times the length L2. It is preferable to set it in the range of 0.5 times to 0.8 times.
The angle θ at which the first inclined section 31 intersects the separated section 32 and the angle θ at which the second inclined section 33 intersects the separated section 32 are set in the range of 90 degrees to 175 degrees. More preferably, it may be set in the range of 115 degrees to 160 degrees.

For example, as a preferable example for forming the sipe 15, the sipe 15 has an amplitude A of 1.0 mm≦A≦1.2 mm, a length L3 of the separation section 32 of 1.0 mm≦L3≦1.6 mm, It is preferable that the angle θ at which the first inclined section 31 intersects with the separated section 32 and the angle θ at which the second inclined section 33 intersects with the separated section 32 are set to 135°≦θ≦145°.
Accordingly, the edge component can be provided not only in the tire circumferential direction but also in the tire width direction, so that the steering stability performance when traveling on ice can be improved.

As shown in FIG. 3, the sipe 15 includes a first sipe portion 15p located on the opening end side of the tread surface 14k, which is the surface of the block 14, and a second sipe portion located inside the first sipe portion 15p in the tire radial direction. Section 15q. In this example, the first and second sipe portions 15p and 15q are linear, and the distance dp between the wall surfaces of the first sipe portion 15p and the distance dq between the wall surfaces of the second sipe portion 15q are the same. That is, the distance between the wall surfaces facing each other in the sipe 15 is the same from the opening end side to the innermost side.
For example, the distance dp and the distance dq are set to 0.1 mm to 0.8 mm, for example. It is preferable to set it to 0.2 mm to 0.5 mm.
Here, the outermost sipe, which is the open end of the sipe 15, is P0, the end P1 of the first sipe portion 15p on the radially inner side of the tire (hereinafter referred to as the first inflection point P1), and the tire of the second sipe portion 15q. The sipe innermost portion P3, which is an end portion on the radially inner side, is defined as a straight line passing through the sipe outermost portion P0 and the sipe innermost portion P3. The end P1 is also an end P2 (hereinafter referred to as a second inflection point P2) on the tire radial direction inner side of the second sipe portion 15q.
The sipe center line m of the sipe 15 is a straight line that is inclined toward the tire circumferential direction end side of the block 14 with respect to the tire radial direction and that passes through the sipe outermost portion P0 and the first inflection point P1. The first sipe inclination line n is inclined to the side opposite to the sipe center line m (the tire circumferential direction center side of the block 14).
Hereinafter, the angle formed by the sipe center line m and the tread surface 14k is the center line inclination angle α, the angle formed by the first sipe inclination line n and the tread surface 14k is the first sipe inclination angle β, and the second sipe inclination line s and the tread surface 14k. The angle formed by and is the second sipe inclination angle ω.
In this example, the centerline inclination angle α is set in the range of 60° to 90°, preferably in the range of 67° to 82°. The first sipe inclination angle β of the first sipe portion 15p is set in the range of 60 degrees to 90 degrees, preferably in the range of 70 degrees to 85 degrees. It is preferable that the centerline inclination angle α and the first sipe inclination angle β are set so that the centerline inclination angle α is larger than the first sipe inclination angle β while satisfying the above range.
The second sipe inclination angle ω of the second sipe portion 15q may be set in the range of 30° to 60°, preferably 37° to 52°.
Further, the first sipe portion 15p and the second sipe portion 15q have the second sipe inclination angle ω with respect to the first sipe inclination angle β while the first sipe inclination angle β and the second sipe inclination angle ω satisfy the above ranges, respectively. It is preferable that the ratio is set in the range of 0.45 to 0.67. More preferably, it may be set in the range of 0.50 to 0.61.
The radial depth d1 that is the length dimension of the first sipe portion 15p in the tire radial direction is set to be 0.25 to 0.52 times the groove depth D of the sipe 15 in the tire radial direction. It is preferable to set it to 0.30 to 0.44 times.
The radial depth d3, which is the length dimension of the second sipe portion 15q in the tire radial direction, is set to 0.44 to 0.81 times the groove depth D of the sipe 15 in the tire radial direction. It It is preferable to set it to 0.53 times to 0.71 times.
The radial depth d3 of the second sipe portion 15q is set to 0.8 times to 5.0 times the radial depth d1 of the first sipe portion 15p. It is preferably set to 1.0 to 3.4 times, more preferably 1.2 to 2.5 times.
In addition, the width of the first sipe portion 15p in the direction orthogonal to the tire radial direction when the sipe 15 is cross-sectionally viewed by a plane perpendicular to the direction in which the sipe 15 continues along the tread surface 14k is w1, and the width of the second sipe portion 15q is When the width is w2, w2≧2w1.
In the present embodiment, the width w2 of the second sipe portion 15q in the sipe 15 can be regarded as the entire width, and is set to a dimension in the range of 0.18 times to 0.44 times the groove depth D, for example. It It is preferable to set it in the range of 0.25 to 0.38.
Further, the width dimension W1 of the first sipe portion 15p in a cross-sectional view is set in the range of 0.01 to 0.3 times the groove depth D. It is preferable to set it in the range of 0.05 to 0.1 times.
The width dimension W4 of the sipe center line m is set in the range of 0.1 to 0.4 times the groove depth D. It is preferable to set it in the range of 0.2 times to 0.3 times.

In this example, as shown in FIG. 4, the four sipes 151 to 154 are arranged so as to be line-symmetric with respect to the center line v of the block 14, and the block end portion 14p and the block end portion 14p side are arranged. The distance between the sipe 151 and the distance b between the block end portion 14q and the sipe 154 on the block end portion 14q side are set to be equal to or greater than the distance a between the adjacent sipes.
It is preferable that the interval a and the interval b have a relationship of a≦b≦1.3a.
That is, when the distance b is smaller than a, the rigidity of the small blocks 141 and 145 on the block end portions 14p and 14q side is reduced, so that the block edge effect is reduced. On the other hand, when the distance b exceeds 1.3a, the small blocks 141 and 145 on the block end portions 14p and 14q side are likely to be lifted and the grounding performance is deteriorated. Therefore, it is preferable that a≦b≦1.3a. The spacing a between the adjacent sipes 15, 15 is not constant, and may be set so as to be large on the end portions 14p, 14q side of the block 14 and small on the center side. In this way, by tilting the sipe, in addition to the deformation at the time of shear input, sipe contact due to the vertical load occurs, and the sipe contact force increases regardless of the input direction, so the reduction of the ground contact area is suppressed. You can

FIG. 5 is a cross-sectional view of a main part of a vulcanizing mold 20 for vulcanizing and molding the tire 10 shown in FIG. 4, and sipes 151 to 154 are bone portions 21 for forming the circumferential groove 12 and the lateral groove 13. It is formed of a thin metal plate called a blade 24 that is provided so as to project from the groove portion 22 surrounded by the arrow toward the cavity 23.
Each of the blades 24 (241 to 244) includes an embedded portion 24a embedded in the groove portion 22 and a protruding portion 24b having the same shape as the sipe 15. The protruding portion 24b includes a flat plate portion 24p corresponding to the first sipe portion 15p, a curved surface portion 24q corresponding to the second sipe portion 15q, and an arc portion 24r corresponding to the bent portion 15r, and the root Q0 of the flat plate portion 24p. Corresponds to the outermost P0 which is the opening end of the sipe 15, and the tip Q3 of the curved surface portion 24q corresponds to the innermost P3 of the sipe 15.

Generally, a 3D sipe having a bent portion in the middle tends to have a large pull-out force from the vulcanization mold 20 after vulcanization. However, the sipe 15 of the present invention is opposite to each other in the tire radial direction. Since the first sipe portion 15p that inclines to the front is provided, the blade 24 also includes the flat plate portion 24p and the curved surface portion 24q that incline in mutually opposite directions with respect to the tire radial direction. Therefore, when the blade 24 is pulled out, as shown in FIG. 6, the flat plate portion 24p pushes the small block on the center side of the block 14 adjacent to the first sipe portion 15p toward the center side of the block 14, and the curved surface portion 24q moves to the second side. The sipe portion 15q pushes the small block at the end of the adjacent block 14 toward the end of the block 14. Therefore, the pull-out force from the vulcanization mold 20 can be further reduced.

On the other hand, the formed sipe 15 has a macro inclination (an inclination having a centerline inclination angle α) that connects the tire tread side, which is the outermost P0 of the sipe, and the innermost portion in the radial direction of the tire, which is the innermost P3 of the sipe. It has a local inclination (an inclination having a first sipe inclination angle β) connecting the tread side and the bending start point (first inflection point P1), and the macro inclination and the local inclination are Since they are on opposite sides to the tire radial direction which is a vertical line to the tire tread surface, the sipe contact force can be increased regardless of the input direction.
Specifically, as shown in FIG. 7, if a force from the one end 14q side that is the end of the block 14 to the other end 14p side that is the end of the block 14 is input, then on the entry side (stepping side) On the one end 14q side, the effect of the local inclination k acts on the end of the small block 146 on the floating side, so that the lifting of the small block 145 is suppressed. On the other hand, on the other end 14p side that is the exit side (kicking side), the effect of the macro inclination K acts on the end of the small block 141 at the end that is the floating side, so that the small block 141 at the end rises. Is suppressed. This is the same even when the input direction is reversed, so that the sipe contact force can be increased regardless of the input direction.

In the present example, as described above, the centerline inclination angle α>the first sipe inclination angle β, the centerline inclination angle α is set in the range of 60 degrees to 90 degrees, and the first sipe inclination angle β is set to 60 degrees. The range is up to 90 degrees. This is because when the centerline inclination angle α is set to 90 degrees, the angle with respect to the tread surface 14k approaches the direction at a right angle, so that the pull-out force decreases but the sipe contact force may decrease. If the centerline inclination angle α is less than 60 degrees, the sipe contact force increases but the pull-out force may increase. Considering this point, the central nucleus inclination angle α is preferably set in the range of 67 degrees to 82 degrees.
The same applies to the first sipe inclination angle β. When the first sipe inclination angle β is set to around 90 degrees, the pull-out force is reduced by the amount that the inclination is gentle, but the sipe contact force is reduced and the first sipe inclination angle β is changed. If the angle is smaller than 60 degrees, the sipe contact force increases but the pull-out force may increase.
Therefore, in this example, the centerline inclination angle α and the first sipe inclination angle β are set within the above range, and the width w2 of the second sipe portion 15q is set to be twice or more the width w1 of the first sipe portion 15p. This makes it possible to reduce the pull-out force when pulling out the vulcanization kettle while ensuring the contact force of the 3D sipes.

Further, in the above-described embodiment, the centerline inclination angle α and the first sipe inclination angle β of the four sipes 151 to 154 are the same, but as shown in FIG. By setting the sipe inclination angle β and the sipe inclination angle β so as to be large on the ends 14p, 14q side of the block 14 and small on the center side, the edge effect of the sipes 151, 154 on the block ends 14p, 14q side can be enhanced. At the same time, since the ground contact area can be secured by the small blocks 142 to 145 at the center, both the ground contact performance and the on-ice performance of the tire can be improved.

Further, in the above-described embodiment, the four sipes 151 to 154 are arranged so as to be line-symmetric with respect to the center line v of the block 14, but the number of sipes 15 is not limited to this, and the block 14 is not limited thereto. It is sufficient that a plurality of them are formed in each. As for the arrangement, as shown in FIG. 9, the direction of the sipe center line m may be the tire circumferential direction. The arrangement shown in FIG. 9 is particularly effective when the input is large from one direction, such as when the braking characteristic is prioritized.
Further, as shown in FIG. 10A, when there is a sipe at the center of the block 14, the sipe 15C located at the center is preferably a 2D sipe. As a result, the same sipe contact force can be obtained even when the input direction is opposite.
Also, as shown in FIG. 10B, even when there is no sipe in the center of the block 14, the sipes 15C and 15C adjacent to the center of the block may be 2D sipes.
As shown in FIG. 10C, even when the sipe is located at the center of the block 14, the sipe 15C located at the center and the sipe 15C' adjacent to the sipe 15C may be 2D sipes.
As described above, since the blade having a simple structure can be used for the sipes near the center of the block, which contribute little to the lifting of the small block, the tire can be easily manufactured.

Further, in the above-described embodiment, the surface shape of the sipe 15 is a trapezoidal wave shape, but it is a 2D sipe having a zigzag shape or a straight portion parallel to the tire width direction and a slope portion inclined to the tire width direction. May be
Further, in the above-described embodiment, the sipe 15 is a 3D sipe extending in a direction parallel to the tire width direction, but a sipe extending in a direction parallel to the tire circumferential direction as shown in FIG. 11A. It may be 18 (181 to 184). In this case, among the sipes 181-184, the sipes 181-184 are arranged so that the radial inclination angles of the tire end side sipes 181,184 are larger than the radial inclination angles of the central sipes 182-184. It may be formed. As a result, when the block 14 receives an input such as a lateral force parallel to the tire width direction, it is possible to effectively prevent the small blocks partitioned by the sipes 181 to 184 from rising from the road surface.
Further, as shown in FIG. 11B, if a sipe 19 extending in a direction intersecting the tire circumferential direction and the tire width direction is provided, the sipe 19 divides the input from multiple directions. Lifting of the small block from the road surface can be effectively suppressed. In this case, of the sipes 19, the absolute value of the radial inclination angle of one of the sipes located on the tire circumferential direction end side of the block 14 and the other sipes is equal to that of the sipes other than the one sipes. It may be larger than the absolute value of the radial tilt angle. In addition, in FIG. 11B, the shape of the block 14 viewed from the tire tread side has two sides 14a and 14c parallel to the tire circumferential direction and two parallel sides intersecting the tire circumferential direction and the width direction. A parallelogram having sides 14b and 14d is used.
Further, as shown in FIG. 11C, in the sipe 15 according to the above-described embodiment, the rib-shaped land portion 16 (or the rib-shaped land portion 16 is divided by the lateral groove) that contributes to the edge effect on the longitudinal force of the brake or the like. In the center block), the sipe 18 is in the shoulder block 14C that contributes to the edge effect on the lateral force, and the sipe 19 is in the intermediate block 14B that is arranged between the rib-shaped land portion 16 and the shoulder block 14C. It is preferable to provide.
As a result, it is possible to effectively prevent the small blocks of the rib-shaped land portion 16 and the blocks 14B and 14C partitioned by the sipes 15, 18, and 19 from rising from the road surface. Therefore, it is possible to effectively improve the ground contact performance of the tire while securing the on-ice performance against not only the longitudinal force but also the lateral force.
In the above embodiment, the extension direction of the circumferential groove 12 is parallel to the tire circumferential direction, and the extension direction of the lateral groove 13 is parallel to the tire width direction. The groove portions adjacent to each other in the tire circumferential direction may have a zigzag shape inclining in mutually opposite directions. The lateral groove 13 may also be a straight line or a curved line inclined with respect to the tire circumferential direction.
The sipe 15 may extend only in the tire width direction or the tire circumferential direction, or may be inclined with respect to the tire circumferential direction.

Although the present invention has been described above using the embodiments, the technical scope of the present invention is not limited to the scope described in the above embodiments. It is apparent to those skilled in the art that various modifications and improvements can be added to the above-described embodiment. It is apparent from the scope of the claims that the embodiments added with such changes or improvements can be included in the technical scope of the present invention.

FIG. 12 is a perspective view of a main part of a tread 11 according to another embodiment. FIG. 13 is a diagram showing details of the sipe shape according to another embodiment.
For example, in the above-described embodiment, the second sipe portion 15q has a straight shape, but as shown in FIGS. 12 and 13, the second sipe portion 15q has a curved shape and the tire radius of the first sipe portion 15p is small. The end P1 on the inner side in the direction and the end P2 on the outer side in the tire radial direction of the second sipe portion 15q may be connected by an arcuate bent portion 15r.

That is, as shown in FIG. 13A, the sipe 15 according to the present embodiment has an opening end to the tread surface 14k when the sipe 15 is viewed in a cross section by a plane perpendicular to the extending direction of the sipe 15 on the tread surface 14k. The first sipe portion 15p located on the side, the second sipe portion 15q located inside the first sipe portion 15p in the tire radial direction, the end portion P1 on the tire radial inner side of the first sipe portion 15p, and the second sipe portion. And an arc-shaped bent portion 15r connecting the end portion P2 of the tire radial direction outer side of 15q. The sipe 15 in the present embodiment extends in the depth direction from the tread surface 14k toward the tire radial direction inner side while the groove walls 15a and 15b that partition the sipe 15 and face each other have the same width. That is, the sipe 15 is molded by the metal thin plate 24 (blade) provided in the vulcanization mold 20 in FIG. 17 and having a constant thickness.
Further, in the present embodiment, for convenience of description, the first sipe portion 15p and the second sipe portion 15q will be described as being directly continuous with the bent portion 15r. That is, the first inflection point P1 is not only the one end of the bent portion 15r but also the end of the first sipe portion 15p. The second inflection point P2 is the other end of the bent portion 15r and also the end of the second sipe portion 15q. In addition, a straight line or a curved line connecting the ends between the first sipe portion 15p and the bent portion 15r, or a straight line or a curved line connecting the ends between the second sipe portion 15q and the bent portion 15r. There may be a connection. In this case, both ends of the bent portion 15r become inflection points where the curvature changes from the connection portion.

As shown in FIG. 13B, when a straight line passing through the sipe outermost portion P0 which is the opening end of the sipe 15 and the sipe innermost portion P3 which is the innermost portion in the tire radial direction is a sipe center line m, the sipe center of the sipe 15 is defined. The line m is inclined with respect to the tire radial direction. Hereinafter, the angle formed by the tread surface 14k and the sipe center line m will be referred to as a center line inclination angle α.
On the other hand, the first sipe portion 15p is linear. Here, when a straight line passing through the sipe outermost portion P0 and the first inflection point P1 is defined as a first sipe inclined line n, the first sipe inclined line n of the sipe 15 is opposite to the sipe center line m (block 14 of the tire in the circumferential direction). Further, the first sipe inclination angle β, which is the angle formed by the tread surface 14k and the first sipe inclination line n, is smaller than the centerline inclination angle α.
The centerline inclination angle α is set in the range of 60° to 90°, preferably 67° to 82°. The first sipe inclination angle β of the first sipe portion 15p is set in the range of 60 degrees to 90 degrees, preferably in the range of 70 degrees to 85 degrees. As will be described later, the fact that the first sipe inclination line n is inclined on the side opposite to the sipe center line m and that the first sipe inclination angle β is larger than the center line inclination angle α are It is not essential to the invention.

The second sipe portion 15q has a curvature radius R larger than the curvature radius r of the bent portion 15r such that the inclination angle of the tangent to the tread surface 14k gradually increases from the tire radial direction outer end to the tire radial direction inner end. The curvature center of the bent portion 15r is on the tire circumferential direction end side of the block 14, and the curvature center of the second sipe portion 15q is on the tire circumferential direction center side of the block 14. That is, the center of curvature of the second sipe portion 15q and the center of curvature of the bent portion 15r are on opposite sides of the sipe 15. The inclination angle of the tangent line in the sipe innermost portion P3 of the sipe 15 is preferably formed so as to extend perpendicularly to the tread surface 14k, for example. Further, the sipe innermost P3 side may include a straight line portion, or the second sipe portion may have a large radius of curvature and become asymptotic to a straight line having an infinite radius of curvature.
If it is a straight line, the hook removal property is improved, and the ground contact area can be secured by sufficiently suppressing the block collapse due to the sipe contact at the outer portion of the straight line portion in the tire radial direction.
The inclination angle of the end of the second sipe portion 15q on the outer side in the tire radial direction is set to 30° to 60°, preferably 37° to 52°.

The radial depth d1 that is the length dimension of the first sipe portion 15p in the tire radial direction is set to be 0.25 to 0.52 times the groove depth D of the sipe 15 in the tire radial direction. Preferably, it is set to 0.30 times to 0.44 times.
The radial depth d3, which is the length dimension of the second sipe portion 15q in the tire radial direction, is set to 0.44 to 0.81 times the groove depth D of the sipe 15 in the tire radial direction. It Preferably, it is set to 0.53 times to 0.71 times. The radial depth d3 of the second sipe portion 15q is set to 0.8 times to 5.0 times the radial depth d1 of the first sipe portion 15p. It is preferably set to 1.0 times to 3.4 times, and more preferably 1.2 times to 2.5 times.

In addition, the overall width W3 of the sipe 15 in cross section is set in the range of 0.18 to 0.44 times the groove depth D. It is preferable to set it in the range of 0.25 to 0.38. The width dimension W3 is almost the width of the second sipe portion 15q except for the bent portion 15r.
Further, the width dimension W1 of the first sipe portion 15p in a cross-sectional view is set in the range of 0.01 to 0.3 times the groove depth D. It is preferable to set it in the range of 0.05 to 0.1 times.
The width dimension W4 of the sipe center line m is set in the range of 0.1 times to 0.4 times the groove depth D. It is preferable to set it in the range of 0.2 times to 0.3 times.
The width dimensions W1, W3, W4 are measured in a direction orthogonal to the tire radial direction when the sipe 15 is viewed in a cross section by a plane perpendicular to the continuous direction of the sipe 15 along the tread surface 14k.
The sipe 15 has a thickness dimension of the first sipe portion 15p, the bent portion 15r, and the second sipe portion 15q.
The distance dp between the wall surfaces of the first sipe portion 15p, the distance dr between the wall surfaces of the bent portion 15r, and the distance dq between the wall surfaces of the second sipe portion 15q are the same. That is, the distance between the wall surfaces facing each other in the sipe 15 is the same from the opening end side to the innermost side. For example, the distances dp, dr, dq are set to 0.1 mm to 0.8 mm, for example. It is preferable to set it to 0.2 mm to 0.5 mm.

Further, as shown in FIG. 13C, the sipe 15 has a convex portion 15u that bulges toward the center of the block 14 and a convex portion 15v that bulges toward the end of the block 14 with respect to the sipe center line m. ing. Here, the convex portion 15u on the outer side in the tire radial direction is the tread side convex portion, and the convex portion 15v on the inner side in the tire radial direction is the inner convex portion, and the maximum value of the distance between the sipe center line m and the convex portion 15u on the tread side is defined as 1 amplitude Wp, when the maximum value of the distance between the sipe center line m and the inner convex portion 15v is the second amplitude Wq, Wq<Wp, and as shown in FIG. 13(d), along the tread surface 14k. When the width of the first sipe portion 15p in the direction orthogonal to the tire radial direction is W1 and the width of the second sipe portion 15q is W2 when a cross section of the sipe 15 is taken along a plane perpendicular to the direction in which the sipe 15 continues. , W2≧2W1. The first amplitude Wp is the maximum value of the shortest distance from each point of the tread side convex portion 15u to the sipe center line m, and the second amplitude Wq is the shortest distance from each point of the inner convex portion 15v to the sipe center line m. It is the maximum value of the distance. In FIG. 13C, the first amplitude Wp is set to almost 0. Further, the inner convex portion 15v' such as Wq'>Wp shown by the broken line in the figure does not satisfy the above condition.

Further, it is preferable that the shortest distance W3 from the end portion Pu of the tread-side convex portion 15u most protruding toward the block center side to the sipe innermost portion P3 is 1.2 mm≦W3≦2.2 mm. The radial depth d2 from the end Pu to the innermost P3 of the sipe is preferably 4.0 mm≦d2≦5.5 mm.
The maximum width W5 of the sipe 15 in the cross-sectional area z is set within a range of 0.4 to 1.2 times the groove depth D up to the innermost sipe P3. It is preferable to set it in the range of 0.6 times to 1.0 times.
The cross-sectional area z refers to a portion surrounded by the groove walls 15a and 15b and the groove bottom 15c forming the sipe 15 in a cross-sectional view, and the maximum width W5 in the cross-sectional area z is from one groove wall 15a to the tread surface 14k. The length of the straight line extending in the tire radial direction toward the tread surface 14k and the straight line extending from the other groove wall 15b toward the tread surface 14k in the tire radial direction is the maximum length.

As shown in FIG. 14A, the sipe 15 includes a first sipe portion 15p located on the tread surface 14k side, a second sipe portion 15q located inside the first sipe portion 15p in the tire radial direction, and a first sipe portion 15p. A sipe portion 15p having a first inflection point P1 that is an inner end in the tire radial direction and a bent portion 15r that connects a second inflection point P2 that is an outer end in the tire radial direction of the second sipe portion 15q, A straight line f1 that connects the innermost sipe P3 that is the inner end of the sipe 15 in the tire radial direction and the second inflection point P2 illustrated in FIG. 14B, and a tangent line f2 at the outer end of the second sipe portion in the radial direction of the tire. And an area S1 surrounded by a tangent line f3 at the end of the second sipe portion 15q on the inner side in the tire radial direction, and a tangent line f2 at the end of the second sipe portion 15q on the outer side in the tire radial direction shown in FIG. 14C. The ratio of the area S2 surrounded by the tangent line f3 and the second sipe portion 15q at the inner end of the second sipe portion 15q in the tire radial direction is preferably 0.05 or more and less than 1.0.

In the present embodiment, the first sipe portion 15p and the second sipe portion 15q are directly connected to the bent portion 15r as described above. Therefore, the area S1 is the inner side in the tire radial direction of the second sipe portion 15q. Of the straight line f1 connecting the inflection point P2 of the tire to the innermost sipe inner side P3 of the tire radial direction, the tangent line f2 at the inflection point P2 of the tire radial outer side, and the tangent line f3 at the innermost sipe inner side P3 of the tire radial direction. The enclosed portion, the area S2, is defined by a center line 15x extending from the second sipe portion 15q, a tangent line f2 at an inflection point P2 on the outer side in the tire radial direction, and a tangent line f3 on an innermost sipe P3 on the inner side in the tire radial direction. It is the enclosed part.

Further, in the sipe 15, the area S2 shown in FIG. 14C has a tangent line at the end of the bent portion 15r on the side of the first sipe portion 15p shown in FIG. 14D and the second sipe portion 15q of the bent portion 15r. It is preferably larger than the area S3 surrounded by the tangent at the side end and the bent portion 15r. That is, the area S2 is defined by a tangent line f4 at an inflection point P1 that is an end point of the bent portion 15r on the outer side in the tire radial direction, a tangent line f2 at an inflection point P2 that is an end point of the bent portion 15r on the inner side in the tire radial direction, and a bend It is formed to be larger than the area S3 surrounded by the portion 15r.
Further, the sipe 15 has an end (P0 in the present embodiment) on the tread surface 14k side of the first sipe portion 15p and an end (P3 in the present embodiment) on the tire radial direction side of the second sipe portion 15q shown in FIG. 14(e). ) Is preferably formed so that the ratio of the area S2 to the area S4 surrounded by the straight line connecting the s) and the sipe 15 is 0.1 or more and 0.9 or less.

Further, as shown in FIG. 14A, in the sipe 15, the inclination angle γ1 at the tread side end (P0 in the present embodiment) of the first sipe portion 15p with respect to the tread surface 14k is the second inflection point P2. It is preferably larger than the inclination angle γ2 in. The inclination angle γ1 is an acute angle side angle between the tangent line f5 and the tread surface 14k at the tread side end (P0 in the present embodiment) of the first sipe portion 15p. When the first sipe portion 15p is a straight line and is directly connected to the bent portion 15r, the inclination angle γ1 is equal to the inclination angle β of the first sipe inclination line n.
Further, in the sipe 15, the inclination angle γ3 at the end of the second sipe portion 15q on the inner side in the tire radial direction (P3 in the present embodiment) with respect to the tread surface 14k is larger than the inclination angle γ2 at the second inflection point P2. Is preferred. The inclination angle γ2, which is the end of the second sipe portion 15q on the outer side in the tire radial direction, is set in the range of, for example, 30 degrees to 60 degrees. Preferably, it may be set in the range of 37 degrees to 52 degrees. The inclination angle γ2 is set in the range of 0.45 to 0.67 times the first sipe inclination angle β. It is preferable to set it in the range of 0.5 times to 0.61 times.

FIG. 14F is a diagram in which the sipe 15 is projected on a plane perpendicular to the tread surface 14k parallel to the extending direction of the sipe 15. As shown in the figure, when the angles and lengths of the respective parts are set as described above, when the sipe 15 is projected on a plane perpendicular to the tread surface 14k parallel to the extending direction of the sipe 15, the sipe 15 extends. The area Sp and the second sipe occupied by the first sipe portion 15p with respect to the entire area Sa (extending direction length L×groove depth D) when the sipe 15 is projected on a plane perpendicular to the tread surface 14k parallel to the direction. The area Sq occupied by the portion 15q is set to have the following relationship.
The area Sp of the first sipe portion 15p is set in the range of 0.22 to 0.54 times the total area Sa. It is preferable to set it in the range of 0.3 times to 0.46 times.
The area Sq of the second sipe portion 15q is set in the range of 0.48 to 0.82 times the total area Sa. It is preferable to set it in the range of 0.52 times to 0.72 times.

In this example, as shown in FIG. 15, the four sipes 151 to 154 are arranged such that the extending directions of the sipes on the tread surface are parallel to each other and are line-symmetric with respect to the center line v of the block 14. The interval between the block end 14p and the sipe 151 on the block end 14p side and the interval b between the block end 14q and the sipe 154 on the block end 14q side are set to be equal to or greater than the interval a between adjacent sipes. The term “parallel” includes not only completely parallel but also an inclination within ±20 degrees.
It is preferable that the interval a and the interval b have a relationship of a≦b≦1.3a. That is, when the distance b is smaller than a, the rigidity of the small blocks 141 and 145 on the block end portions 14p and 14q side is reduced, so that the block edge effect is reduced. On the other hand, when the interval b exceeds 1.3a, the small blocks 141 and 145 on the block end portions 14p and 14q side are likely to be lifted, and the grounding performance is deteriorated. Therefore, it is preferable that a≦b≦1.3a.

Further, the sipes 151 to 154 are set such that the sipes shortest distance x, which is the shortest distance from the adjacent sipes, is 0.4 to 1.2 times the groove depth D. It is preferable to set it in the range of 0.6 times to 1.0 times. The shortest sipe distance x is, for example, when the sipe center line m is inclined in the same direction like the sipes 151 and 152, the groove wall 151a and the groove wall 152b that partition the small block 142 are defined. The shortest distance is the shortest distance between the groove wall 152a and the groove wall 153a that partition the small block 143 when the sipe center lines m are provided so as to intersect each other like the sipes 152 and 153.
The distance a between the sipes 151 to 154 set by the shortest sipes distance x is preferably 2.4 mm≦a≦7.0 mm. By setting the spacing a of the sipes 15 in this manner, the block rigidity of the small blocks 142 to 144 can be ensured.
The spacing a between the adjacent sipes 15, 15 is not constant and may be set to be large on the block end portions 14p, 14q side and small on the center side.
In this way, by tilting the sipe 15, in addition to the deformation at the time of shearing input, the contact of the sipe due to the vertical direction load occurs, and the sipe contact force increases regardless of the input direction, so that the reduction of the ground contact area is suppressed. can do.

FIG. 16 is a cross-sectional view of a main part of a vulcanizing mold 20 for vulcanizing and molding the tire 10 shown in FIG. 15, and sipes 151 to 154 are bone parts 21 for forming the circumferential groove 12 and the lateral groove 13. It is formed by a metal thin plate 24 called a blade, which is provided so as to project from the groove portion 22 surrounded by the arrow toward the cavity 23.
Each of the blades 24 (241 to 244) includes an embedded portion 24a embedded in the groove portion 22 and a protruding portion 24b having the same shape as the sipe 15. The protruding portion 24b includes a flat plate portion 24p corresponding to the first sipe portion 15p, a curved surface portion 24q corresponding to the second sipe portion 15q, and an arc portion 24r corresponding to the bent portion 15r, and the root Q0 of the flat plate portion 24p. Corresponds to the outermost P0 which is the opening end of the sipe 15, and the tip Q3 of the curved surface portion 24q corresponds to the innermost P3 of the sipe 15.

Generally, a 3D sipe having a bent portion in the middle tends to have a large pull-out force from the vulcanization mold 20 after vulcanization, but as shown in FIG. Since the bent portion 15r has an arc shape and the second sipe portion 15q located on the inner side in the tire radial direction has a gentle curve (an arc shape having a large radius of curvature), the first sipe portion 15p and the second sipe portion 15q. As a result, it is possible to significantly reduce the pull-out force when the vulcanization kettle is pulled out, while securing the sipe contact force.
Further, since the blade 24 includes the flat plate portion 24p and the curved surface portion 24q that are inclined in the directions opposite to each other with respect to the tire radial direction, when the blade 24 is pulled out, as shown in FIG. The first sipe portion 15p pushes the small block on the center side of the adjacent block 14 to the center side of the block 14, and the curved surface portion 24q moves the small block at the end of the block 14 to which the second sipe portion 15q is adjacent to the end of the block 14. I will push the department side. Therefore, the pull-out force from the vulcanization mold 20 can be further reduced.

On the other hand, the formed sipe 15 has a macro inclination (an inclination having a centerline inclination angle α) that connects the tire tread side, which is the outermost P0 of the sipe, and the innermost portion in the radial direction of the tire, which is the innermost P3 of the sipe. There is a local inclination (an inclination having a first sipe inclination angle β) connecting the tread side and the bending start point (first inflection point P1), and the macro inclination and the local inclination are The sipe contact force can be increased irrespective of the input direction because the tire radial directions, which are vertical lines to the tire tread surface, are opposite to each other.
Specifically, as shown in FIG. 18, if a force is applied from the one end side (14q side) of the block 14 to the other end side (14p side), the local inclination is obtained on the one end 14q side which is the entrance side. Since the effect of k acts on the end of the small block 145 on the floating side, the lifting of the small block 145 is suppressed. On the other hand, on the other end side that is the exit side, the effect of the macro inclination K acts on the end portion of the small block 141 at the end portion that is the floating side, so that the lifting of the small block 141 at the end portion is suppressed. This is the same even when the input direction is reversed, so that the sipe contact force can be increased regardless of the input direction.

The centerline inclination angle α is preferably set in the range of 60 degrees to 90 degrees as described above. If the centerline inclination angle α is set to 90 degrees, the angle with respect to the tread surface 14k approaches the direction at right angles, so the pull-out force decreases but the sipe contact force may decrease. If the centerline inclination angle α is less than 60 degrees, the sipe contact force increases but the pull-out force may increase. Considering this point, the central nucleus inclination angle α is preferably set in the range of 67 degrees to 82 degrees.
The same applies to the first sipe inclination angle β, but the sipe 15 of the present invention, as shown in FIG. 13(a), has a bend radius 15r and a radius of curvature R larger than the radius of curvature r of the bend radius 15r. Since the sipe portion 15q is provided, even if β>90 (the first sipe portion 15p is inclined in the same direction as the sipe center line m), the sipe contact force is ensured and the vulcanization kettle is pulled out. The pull-out force at time can be reduced.
Further, as shown in FIG. 13C, it is preferable that the second amplitude Wq be smaller than the first amplitude Wp. This is because when the second amplitude Wq is made larger than the first amplitude Wp, as shown by the broken line in FIG. 13C, a convex portion that greatly protrudes from the sipe center line m is formed inside the sipe 15 in the tire radial direction. This is because the pulling force increases when the vulcanization kettle is pulled out.
On the other hand, if the second amplitude Wq is narrowed in order to improve the hook removal property, the contact force of the 3D sipe will decrease. Therefore, in this example, Wq<Wp is set, and as shown in FIG. 13D, the width W2 of the second sipe portion 15q is set to be twice or more the width W1 of the first sipe portion 15p. The pulling force when the vulcanization kettle is pulled out can be reduced while securing the contact force of the 3D sipes.

For example, in the above-described embodiment, the second sipe portion 15q has an arc shape with a radius of curvature of R, but may have a curved shape (curving includes a straight line having a very large radius of curvature). Further, as shown in FIG. 19A, a curved shape may be formed by a plurality of arcs Ck (k=1 to n) having different radii of curvature R1, R2,..., Rn. In this case, it goes without saying that all the centers of curvature of the arcs Ck are located on the opposite side to the center of curvature of the first sipe portion 15p.
Also, when the arc on the bent portion 15r side is C1 and the arc on the sipe innermost P3 side is Cn, the radius of curvature Rk of each arc Ck (k=1 to n) increases as it goes inward in the tire radial direction. For example, the shape of the second sipe portion 15q becomes smoother, and the distance from the sipe center line m becomes smaller toward the inner side in the tire radial direction, so that the pull-out force when the vulcanization kettle is pulled out can be further reduced. ..
Further, as shown in FIG. 19B, the deepest portion of the second sipe portion 15q may be a straight line (Rn=∞).
The radii of curvature Rk, Rk+1 of two adjacent arcs Ck, Ck+1 do not necessarily have to satisfy the relationship of Rk<Rk+1. It is preferable because the shape of 15q can be made smoother.
The bent portion 15r may be a curved line, and may not have an arc shape.

Further, in the above-described embodiment, the centerline inclination angle α and the first sipe inclination angle β of the four sipes 151 to 154 are the same, but as shown in FIG. If the sipe inclination angle β is set to be large on the block ends 14p, 14q side and small on the center side, the edge effect by the sipes 151, 154 on the block ends 14p, 14q side can be enhanced, and Since the ground contact area can be secured by the small blocks 142 to 144 in the center, both the ground contact performance and the on-ice performance of the tire can be improved.

Further, in the above-described embodiment, the four sipes 151 to 154 are arranged so as to be line-symmetric with respect to the center line v of the block 14, but the number of sipes 15 is not limited to this, and the block 14 is not limited to this. It is sufficient that a plurality of them are formed in each. As for the arrangement, as shown in FIG. 21, the direction of the sipe center line m may be entirely the tire circumferential direction. The arrangement shown in FIG. 21 is particularly effective when the input from one direction is large, such as when the braking characteristic is prioritized.
Further, as shown in FIG. 22A, when there is a sipe at the center of the block 14, the sipe 15C located at the center is preferably a 2D sipe. As a result, the same sipe contact force can be obtained even when the input direction is opposite.
Further, as shown in FIG. 22B, even when there is no sipe in the center of the block 14, the sipes 15c and 15c adjacent to the center of the block may be 2D sipes.
Note that, as shown in FIG. 22C, even when the sipe is located at the center of the block 14, the sipe 15C located at the center and the sipe 15C' adjacent to this sipe 15C may be 2D sipes. ..
As described above, since the blade having a simple structure can be used for the sipes near the center of the block, which contribute little to the lifting of the small block, the tire can be easily manufactured.

In addition, in the above-described embodiment, the surface shape of the sipe 15 is a trapezoidal wave shape, but as a 2D sipe having a zigzag shape, or a linear portion parallel to the tire width direction and an inclined portion inclined with respect to the tire width direction. Good.
Further, in the above-described embodiment, the sipe 15 is a 3D sipe extending in a direction parallel to the tire width direction, but a sipe extending in a direction parallel to the tire circumferential direction as shown in FIG. It may be 18 (181 to 184). In this case, among the sipes 181-184, the sipe 181-184 are arranged so that the tire end-side sipes 181, 184 have a larger inclination angle in the tire radial direction than the central-side sipes 182, 183. 184 may be formed. As a result, when the block 14 receives an input such as a lateral force parallel to the tire width direction, it is possible to effectively prevent the small blocks partitioned by the sipes 181 to 184 from rising from the road surface.
Further, as shown in FIG. 23( b ), if a sipe 19 extending in a direction intersecting the tire circumferential direction and the tire width direction is provided, the sipe 19 divides the input from multiple directions. Lifting of the small block from the road surface can be effectively suppressed. In this case, of the sipes 19, the absolute value of the radial inclination angle of one of the sipes located on the tire circumferential direction end side of the block 14 and the other sipes is equal to that of the sipes other than the one sipes. It may be larger than the absolute value of the radial tilt angle. In addition, in FIG. 23B, the shape of the block 14 viewed from the tire tread side has two sides 14a and 14c parallel to the tire circumferential direction and two parallel sides crossing the tire circumferential direction and the width direction. A parallelogram having sides 14b and 14d is used.
Further, as shown in FIG. 23C, in the sipe 15 of the above-described embodiment, the rib-shaped land portion 16 (or the rib-shaped land portion 16 is divided by the lateral groove) that contributes to the edge effect on the longitudinal force of the brake or the like. In the center block), the sipe 18 is in the shoulder block 14C that contributes to the edge effect on the lateral force, and the sipe 19 is in the intermediate block 14B that is arranged between the rib-shaped land portion 16 and the shoulder block 14C. It is preferable to provide.
As a result, it is possible to effectively prevent the small blocks of the rib-shaped land portion 16 and the blocks 14B and 14C partitioned by the sipes 15, 18, and 19 from rising from the road surface. Therefore, it is possible to effectively improve the ground contact performance of the tire while securing the on-ice performance against not only the longitudinal force but also the lateral force.
In the above embodiment, the extension direction of the circumferential groove 12 is parallel to the tire circumferential direction, and the extension direction of the lateral groove 13 is parallel to the tire width direction. It may have a zigzag shape in which the groove portions adjacent to each other in the tire circumferential direction are inclined in opposite directions. The lateral groove 13 may also be a straight line or a curved line inclined with respect to the tire circumferential direction.
The sipe 15 may extend only in the tire width direction or the tire circumferential direction, or may be inclined with respect to the tire circumferential direction.

10 tires, 11 treads, 12 circumferential grooves, 13 lateral grooves, 14 blocks,
15, 151-156 sipe, 15m straight part, 15n inclined part,
15p first sipe portion, 15q second sipe portion, 15r bent portion,
16 Rib-shaped land area.

Claims (5)

A tire having a sipe that opens to a tread surface of a land portion formed in a tread portion by a groove extending in a tire circumferential direction or a tire width direction ,
The sipe is
In the shape that opens on the tread,
A trapezoidal corrugated portion protruding two on one side and one on the other side by being alternately provided while being inverted to one side and the other side with the center line in the extending direction of the sipe being sandwiched therebetween,
A linear portion that extends linearly from both ends of the trapezoidal wavy portion along an extension direction center line, and that opens to a groove wall forming a land portion;
In the shape when viewed in cross section by a plane perpendicular to the continuous direction of the sipe along the tread surface,
A first sipe portion, one end of which opens in the tread surface and extends linearly inward in the tire radial direction ;
Located in the tire radial direction inner side of the first sub type section, and a second sipe portion extending in a straight line or an arc shape toward the inner side in the tire radial direction,
The sipe center line, which is a straight line connecting the outermost sipe, which is the end of the first sipe portion that opens to the tread surface , and the innermost sipe, which is the end of the second sipe portion on the tire radial inner side, and 1 is a direction of extension of the support type unit, both inclined with respect to the tire radial direction, and the inclination angle is in opposite directions to each other,
One end of the second sipe portion is directly connected to an end portion of the first sipe portion on the inner side in the tire radial direction, or via an arc-shaped bent portion whose center of curvature is located on the sipe center line side, A tire that is inclined with respect to an extension direction of the first sipe portion . The magnitude of the centerline inclination angle, which is the angle formed by the sipe centerline of the sipe and the tire radial direction, is the first sipe inclination angle that is the angle formed by the extension direction of the first sipe portion and the tire radial direction. The tire according to claim 1, wherein the tire is larger than the size. The tire according to claim 2, wherein the magnitude of the first sipe inclination angle is in the range of 60 degrees to 90 degrees, and the magnitude of the centerline inclination angle is in the range of 60 degrees to 90 degrees. .. The width of the second sipe portion in the direction perpendicular to the tire radial direction in the plane perpendicular to the extension direction of the sipe on the tread surface is perpendicular to the extension direction of the sipe on the tread surface of the first sipe portion. The tire according to claim 3, wherein the tire has a width that is at least twice the width in a plane perpendicular to the tire radial direction. Before Symbol the second sipe part,
When connected to the first sipe portion via the bent portion,
An arc shape having a radius of curvature larger than the radius of curvature of the bent portion, or, the radius of curvature is larger toward the inner side in the tire radial direction, and the center of curvature is formed of a curve all on one side of the sipe center line,
The tire according to any one of claims 1 to 4, wherein the center of curvature of the second sipe portion and the center of curvature of the bent portion are on opposite sides of the sipe.