JP2023066316A - tire - Google Patents

Abstract

To provide a tire improved in on-ice gripping performance.SOLUTION: In a tire 10, a plurality of first sipe units 60A composed of a pair of first sipes, and a plurality of second sipe units 60B composed of a pair of second sipe units, are disposed on at least one land part. All of the first sipes and the second sipes have both ends terminating in the land part. The pair of first sipes has a long side and a short side, which are arranged oppositely to each other in a tire circumferential direction and extend incliningly with respect to a tire width direction so as to face one side in the tire circumferential direction. The pair of second sipes has a long side and a short side that are disposed oppositely to each other in the tire circumferential direction and extend in the tire width direction. The first sipe units 60A and the second sipe units 60B are offset-disposed in the tire width direction.SELECTED DRAWING: Figure 1

Description

The present invention relates to tires.

BACKGROUND ART Conventionally, there is known a tire in which sipes are arranged at a high density while suppressing a decrease in rigidity, thereby improving grip performance on ice (for example, Patent Document 1).

Japanese Patent Application Laid-Open No. 2005-186827

However, in Patent Document 1, it is not sufficient to achieve both suppression of rigidity reduction and high-density arrangement of sipes, and there is still room for improvement in grip performance on ice.

SUMMARY OF THE INVENTION Accordingly, an object of the present invention is to provide a tire with improved ice grip performance.

The gist of the present invention is as follows.
A tire having at least one land on the tread surface of the tire,
A first sipe unit comprising a pair of first sipes and a second sipe unit comprising a pair of second sipes are arranged on at least one of the land portions,
Both ends of the first sipe and the second sipe terminate within the land portion,
One first sipe and the other first sipe, which constitute the pair of first sipes in the first sipe unit, are arranged to face each other in the tire circumferential direction and are arranged on one side in the tire width direction. Having a long side that extends obliquely with respect to the tire width direction so as to go toward one side in the tire circumferential direction as it goes,
The one first sipe has a short side extending from one end of the long side in the tire width direction to approach the other first sipe,
The other first sipe has a short side extending from the other end of the long side in the tire width direction so as to approach the one first sipe,
One second sipe and the other second sipe, which constitute the pair of second sipes in the second sipe unit, are arranged facing each other in the tire circumferential direction and each have a length extending in the tire width direction. has an edge,
The one second sipe has a short side extending from one end of the long side in the tire width direction to approach the other second sipe,
The other second sipe has a short side extending from the other end of the long side in the tire width direction so as to approach the one second sipe,
A tire, wherein the first sipe unit and the second sipe unit are offset from each other in the tire width direction.
ADVANTAGE OF THE INVENTION According to the tire of this invention, ice grip performance can be improved.

In the tire of the present invention,
A plurality of the first sipe units and the second sipe units are arranged adjacent to each other in the tire circumferential direction to form a first sipe unit row and a second sipe unit row, respectively. , The first sipe unit row and the second sipe unit row are preferably offset from each other in the tire width direction.
Thereby, the rigidity of the land portion can be sufficiently increased.

In the tire of the present invention,
In the plurality of first sipe units in the first sipe unit row, the short sides of the one of the plurality of first sipes extend on the same straight line along the tire circumferential direction, The short sides of the first sipe extend on the same straight line along the tire circumferential direction,
In the plurality of second sipe units in the second sipe unit row, the short sides of the one of the plurality of second sipes extend on the same straight line along the tire circumferential direction, It is preferable that the short sides of the second sipes extend on the same straight line along the tire circumferential direction.
Thereby, it is easy to dispose a plurality of sipe units uniformly and at a high density without forming useless voids in the land portion.

In the tire of the present invention,
In the first sipe unit row and the second sipe unit row, which are adjacent in the tire width direction,
Of the plurality of first sipe units in the first sipe unit row, the second sipe unit row side of the short side of the one first sipe or the short side of the other first sipe the short side positioned at
Of the plurality of second sipe units in the second sipe unit row, of the short side of the one second sipe or the short side of the other second sipe, the first sipe unit row side It is preferable that the short sides arranged on the sides extend on the same straight line along the tire circumferential direction.
As a result, the braking force and driving force due to the edge component can be sufficiently exerted over the entire width of the tire width direction region where the first sipe unit row and the second sipe unit row are arranged, and the block land portion can be grounded. Uniform pressure distribution can be achieved.

In the tire of the present invention,
In the first sipe unit, each of the one first sipe and the other first sipe has the short side extending along the tire circumferential direction,
In the second sipe unit, the short sides of the one second sipe and the other second sipe preferably extend along the tire circumferential direction.
This will
The sipes capable of exerting braking force and driving force against input in the tire circumferential direction can be arranged more efficiently, and a decrease in rigidity of the land portion around the short side can be more effectively suppressed. .

In the tire of the present invention,
In the first sipe unit, the one first sipe and the other first sipe have the long sides and the short sides extending parallel to each other, and the one first sipe and the other first sipe extend parallel to each other. 2 sipes are arranged offset in the tire width direction,
In the second sipe unit, the one second sipe and the other second sipe have the long sides and the short sides extending parallel to each other, and the one second sipe and the other second sipe extend parallel to each other. The two sipes are preferably offset in the tire width direction.
As a result, the braking force and the driving force due to the edge component can be sufficiently exerted, and the ground contact pressure distribution of the land portion can be made uniform.

In the tire of the present invention,
In the first sipe unit, the one first sipe and the other first sipe are formed by the long side and the short side, and the one first sipe and the other first sipe are opposed to each other. The angle on the side to do is 90 ° or more,
In the second sipe unit, the one second sipe and the other second sipe are formed by the long side and the short side, and the one second sipe and the other second sipe are opposed to each other. It is preferable that the angle of the facing side is 90° or more.
As a result, it is possible to improve the productivity of the tire, prevent the contact pressure difference from becoming large, and more effectively exert the braking force and the driving force in the tire circumferential direction.

In the tire of the present invention,
In the first sipe unit, the one first sipe and the other first sipe are congruent with each other,
Said 2nd sipe unit WHEREIN: It is preferable that said one 2nd sipe and said other 2nd sipe are mutually congruent.
Thereby, thereby, it is easy to arrange a sipe unit uniformly and with high density in a land part.

In the tire of the present invention,
In the first sipe unit, each of the one first sipe and the other first sipe has a ratio of a length along the extending direction of the long side to a length along the extending direction of the short side. is 1 to 15,
In the second sipe unit, the one second sipe and the other second sipe each have a ratio of length along the extending direction of the long side to length along the extending direction of the short side. is preferably 1-15.
As a result, excessive reduction in sipe density or excessive reduction in land portion rigidity can be suppressed, and the durability of the blades that form the sipes during tire manufacturing can be improved.

In the tire of the present invention,
The first sipe unit has a ratio of a tire circumferential length along the tire circumferential direction to a tire width direction length along the tire width direction of 0.1 to 2.6,
The second sipe unit preferably has a ratio of the tire circumferential length along the tire circumferential direction to the tire width direction length along the tire width direction of 0.1 to 2.6.
As a result, it is possible to ensure sufficient block rigidity and obtain a sufficient effect on the braking/driving force.

According to the present invention, it is possible to provide a tire with improved ice grip performance.

1 is a diagram schematically showing a developed view of a tread surface of a tire according to an embodiment of the present invention; FIG. It is a figure for demonstrating the 1st sipe unit in FIG. It is a figure for demonstrating the 2nd sipe unit in FIG. It is a figure for demonstrating arrangement|positioning etc. of a 1st Sipe unit and a 2nd Sipe unit which expands and shows a part of FIG. It is a figure for demonstrating another arrangement|positioning etc. of a 1st sipe unit and a 2nd sipe unit. It is a figure which expands and shows one of the block land parts in FIG. FIG. 6(a) is a diagram showing a comparative example of the block land portion, FIG. 6(b) is a diagram showing a comparative example of the block land portion, and FIG. 6(c) is a diagram showing a comparison of the block land portion. Fig. 6(d) is a diagram showing an example of a block land portion; Fig. 6(e) is a diagram showing an example of a block land portion; 4A and 4B are diagrams showing an embodiment of a block land portion; FIG. FIG. 7 is a graph showing block rigidity and actual contact area in the comparative example and the example shown in FIG. 6; FIG.

Hereinafter, embodiments of the tire according to the present invention will be described by way of example with reference to the drawings. The same reference numerals are given to common components in each figure.

FIG. 1 is a plan view schematically showing a developed view of a tread surface of a tire according to one embodiment of the present invention.

As used herein, the term “tread surface (1)” refers to a tire that is mounted on a rim and has a predetermined internal pressure, and when the tire is rolled with the maximum load applied, it comes into contact with the road surface. , means the outer peripheral surface of the tire over its entire circumference.
In this specification, "tread edge (TE)" means an edge in the tire width direction of the tread surface (1).
Here, "rim" is an industrial standard valid for the region where tires are produced and used. Technical Organization) STANDARDS MANUAL, TRA (The Tire and Rim Association, Inc.) YEAR BOOK, etc. in the United States, or standard rims in applicable sizes that will be described in the future (ETRTO STANDARDS MANUAL is Measuring Rim , Design Rim in TRA's YEAR BOOK) (i.e., the above "rim" includes not only current sizes but also sizes that may be included in the above industrial standards in the future. "Sizes to be described in the future") An example of this is the size listed as "FUTURE DEVELOPMENTS" in the 2013 edition of ETRTO's STANDARDS MANUAL.) However, if the size is not listed in the above industrial standards, it corresponds to the bead width of the tire. A rim with a wider width.
In addition, "predetermined internal pressure" refers to the air pressure (maximum air pressure) that corresponds to the maximum load capacity of a single wheel in the applicable size and ply rating described in the above JATMA YEAR BOOK, etc., and is described in the above industrial standards. For sizes without , it means the air pressure (maximum air pressure) corresponding to the maximum load capacity specified for each vehicle on which the tire is installed.
"Maximum load" means the load corresponding to the maximum load capacity.
The air referred to here can be replaced with an inert gas such as nitrogen gas.

In this specification, unless otherwise specified, the dimensions of each element such as grooves, sipes, block land portions, etc. shall be measured under the "reference condition" described later. "Reference state" refers to a state in which the tire is mounted on a rim, filled with the predetermined internal pressure, and unloaded. Here, the dimensions of each element such as grooves, sipes, and block land portions on the tread surface are measured in a developed view of the tread surface. Here, in the present specification, "a developed view of the tread surface" refers to a plan view of the tread surface with the tread surface being developed on a plane.

In this specification, the "groove width" shall be measured in a direction parallel to the tread surface in a cross section perpendicular to the extending direction of the groove on the tread surface in the above reference state. The groove width may be constant or may vary in the direction perpendicular to the tread surface. However, in this specification, unless otherwise specified, the "groove width" refers to the groove width on the tread surface. In addition, the "groove depth" in this specification shall be measured in a direction perpendicular to the tread surface in the above reference state.

As used herein, the term "sipe" refers to a sipe having a width of 1 mm or less over a region of 50% or more of the sipe depth in the above-described reference state. The sipe width is desirably 0.6 mm or less. Here, the "sipe depth" shall be measured in the direction perpendicular to the tread surface in the above state, and the "sipe width" shall be measured in the cross section perpendicular to the extending direction of the sipe on the tread surface in the above reference state. It shall be measured in a direction parallel to the tread surface. The sipe width may be constant or may vary in the direction perpendicular to the tread surface.

Further, in this specification, the ``length along the direction in which the short side extends'' and the ``length along the direction in which the long side extends'' of the sipe refer to the center point of the sipe in the width direction. It refers to the length of the line, and unless otherwise specified, the distance between each component of each sipe is also measured in a developed view of the tread surface with the center line as a reference.

In this specification, for the sake of convenience, one side in the tire circumferential direction (the upper side in FIG. 1) is referred to as the “CD1 side in the tire circumferential direction”, and the other side in the tire circumferential direction (the lower side in FIG. 1) is referred to as the “CD2 side in the tire circumferential direction. ”.
Further, in this specification, for convenience, the one side in the tire width direction (the right side in FIG. 1) is referred to as the “tire width direction WD1 side”, and the other side in the tire width direction (the left side in FIG. 1) is referred to as the “tire width direction WD2 called "side". Furthermore, in this specification, of the two types of sipes, sipe units, and sipe unit trains, for convenience, one is called the first sipe, the first sipe unit, and the first sipe unit train, and the other is called the second sipe. , the second sipe unit and the second sipe unit train, these can be read interchangeably. That is, if one of the sipes, the sipe unit, and the sipe unit train is tentatively called the first sipe, the first sipe unit, and the first sipe unit train, the other is the second sipe, the second sipe unit, and the second sipe unit. They are simply called unit columns.

A tire 10 according to one embodiment of the present invention has at least one land portion on the tread surface 1 . In the example shown in FIG. 1, the tire 10 of this embodiment has a plurality of (four in the example shown) circumferential main grooves 2 (2a, 2b, 2c and 2d) extending in the tire circumferential direction on the tread surface 1. are doing. Each circumferential main groove 2 may extend substantially straight along the tire circumferential direction, as shown in FIG.

Although the groove width of each circumferential main groove 2 is not particularly limited, it can be set to 4 to 15 mm, for example. Similarly, the groove depth of the circumferential main groove 2 is not particularly limited, but can be, for example, 6 to 20 mm.

In addition, the tire 10 of the present embodiment has a plurality of (five in the illustrated example) land portions 3 (3a , 3b, 3c, 3d and 3e) are partitioned.

In this embodiment, each land portion 3 is divided into a plurality of block land portions 5 by a plurality of lateral grooves 4 extending in a direction intersecting the tire circumferential direction. In the example shown in FIG. 1, the land portion 3a has a plurality of block land portions 51 that are partitioned by lateral grooves 41 and arranged along the tire circumferential direction. The land portion 3b has a plurality of block land portions 52 defined by the lateral grooves 42 and arranged along the tire circumferential direction. The land portion 3c is partitioned by the lateral grooves 43 and has a plurality of block land portions 53 arranged along the tire circumferential direction. The land portion 3d has a plurality of block land portions 54 that are partitioned by the lateral grooves 44 and arranged along the tire circumferential direction. The land portion 3e has a plurality of block land portions 55 defined by the lateral grooves 45 and arranged along the tire circumferential direction.
Each land portion 3 can also be a rib-like land portion that is not partitioned by lateral grooves.

Although the groove width of each lateral groove 4 is not particularly limited, it can be set to 2 to 10 mm, for example. Similarly, the groove depth of each lateral groove 4 is not particularly limited, but can be, for example, 5 to 20 mm.

In this embodiment, at least one of the land portions, each block land portion 5 in the illustrated example, includes a pair of first sipes 6a and 6b (hereinafter referred to as one first sipe 6a and the other first sipe 6b, or simply A first sipe unit 60A consisting of a first sipe 6a and 6b) and a pair of second sipes 6c and 6d (hereinafter, one second sipe 6c and the other second sipe 6d, or simply the second sipe 6c and 6d) are arranged in plurality. In the example shown in FIG. 1, six first sipe units 60A and six second sipe units 60B are arranged in each of the block land portions 52, 53 and 54, and the block land portions 51 and 55 each include: Three each of the first Sipe units 60A and the second Sipe units 60B are arranged.

In addition, the tread surface 1 of the tire 10 of this embodiment is not limited to the example shown in FIG. It may have any tread pattern as long as it has the second sipe unit 60B.

The first sipe unit 60A and the second sipe unit 60B in the tire 10 of this embodiment will be described in detail with reference to FIGS. 1, 2A, 2B and 3. FIG. FIG. 2A is a diagram for explaining the first sipe unit 60A, FIG. 2B is a diagram for explaining the second sipe unit 60B, and FIG. 3 is an enlarged view of part of FIG. , a diagram for explaining the arrangement and the like of a first sipe unit 60A and a second sipe unit B. FIG.

In the tire 10 of this embodiment, both ends of the first sipes 6 a and 6 b and the second sipes 6 c and 6 d are terminated within the block land portion 5 . As shown in FIG. 1, one first sipe 6a and the other first sipe 6b that constitute the first sipe unit 60A, and one second sipe 6c and the other first sipe 6c that constitute the second sipe unit 60B. Both ends of the two sipes 6 d terminate within the block land portion 5 .

Further, as shown in FIG. 2A, in the tire 10 of the present embodiment, one first sipe 6a and the other first sipe 6b in the first sipe unit 60A are arranged to face each other in the tire circumferential direction. In addition, each has a long side extending in the tire width direction. In the present embodiment, one first sipe 6a and the other first sipe 6b in the first sipe unit 60A extend in the tire width direction so as to move toward one side in the tire width direction toward one side in the tire width direction. It has a long side extending obliquely with respect to it. More specifically, as shown in FIG. 2A , one first sipe 6a and the other first sipe 6b are separated from each other, and at least a portion (in this example, a portion) of each of them is connected to each other. They are arranged facing each other in the circumferential direction. Further, as shown in FIG. 2A, one first sipe 6a is inclined with respect to the tire width direction so as to move toward the tire circumferential direction CD1 side from the tire width direction WD2 side toward the tire width direction WD1 side. has a long side 61a extending The other first sipe 6b has a long side 61b that extends obliquely with respect to the tire width direction so as to extend toward the tire circumferential direction CD1 side from the tire width direction WD2 side toward the tire width direction WD1 side. there is In this way, both the long sides 61a and 61b extend upward and to the right on the plane of the drawing by being inclined toward the tire circumferential direction CD1 as they go toward the tire width direction WD1.
Here, in this specification, "extending in the tire width direction" means extending with at least a tire width direction component. That is, "extending in the tire width direction" may extend along the tire width direction (that is, at an angle of 0° with respect to the tire width direction, without being inclined with respect to the tire width direction). , means that it may extend obliquely with respect to the tire width direction (that is, obliquely with respect to the tire width direction at an inclination angle of more than 0° with respect to the tire width direction).
In the illustrated example, the long sides 61a and 61b have the same inclination angles θ1 and θ2 with respect to the tire width direction and are inclined at the same inclination angle, but they may be inclined at different inclination angles.

One first sipe 6a has a short side extending from an end e1 on one side of the long side 61a in the tire width direction (the WD2 side in the tire width direction in the illustrated example) toward the other first sipe 6b. 62a. As shown in FIG. 2A, the short side 62a extends toward the side where the one first sipe 6a and the other first sipe 6b face each other, forming a bending angle θ3 with the long side 61a.
The other first sipe 6b is arranged so as to approach one first sipe 6a side from an end e2 on the other side (in the illustrated example, the tire width direction WD1 side) of the long side 61b with respect to the one side in the tire width direction. It has a short side 62b extending to the . As shown in FIG. 2A, the short side 62b extends toward the side where the one first sipe 6a and the other first sipe 6b face each other, forming a bending angle θ4 with the long side 61b.
In one first sipe 6a and the other first sipe 6b, of the ends on either side of the long sides 61a and 61b in the tire width direction, the side where the short sides 62a and 62b are not provided. No short sides extend from the ends.

As shown in FIG. 2B, in the tire 10 of the present embodiment, one second sipe 6c and the other second sipe 6d in the second sipe unit 60B are arranged to face each other in the tire circumferential direction, Each has a long side extending in the tire width direction. In the present embodiment, one second sipe 6c and the other second sipe 6d in the second sipe unit 60B extend in the tire width direction so as to move toward the other side in the tire width direction toward the other side in the tire width direction. It has a long side extending obliquely with respect to it. More specifically, as shown in FIG. 2B, one second sipe 6c and the other second sipe 6d are separated from each other, and at least a portion (in this example, a portion) of each of them is connected to the tire. They are arranged facing each other in the circumferential direction. As shown in FIG. 2B , one second sipe 6 c extends obliquely with respect to the tire width direction so as to move toward the tire circumferential direction CD2 side from the tire width direction WD2 side toward the tire width direction WD1 side. It has a long side 61c. The other second sipe 6d has a long side 61d that extends obliquely with respect to the tire width direction so as to move toward the tire circumferential direction CD2 as it goes from the tire width direction WD2 side toward the tire width direction WD1 side. there is In this manner, both the long sides 61c and 61d extend downward to the right on the paper surface by being inclined toward the tire circumferential direction CD2 as they go toward the tire width direction WD1.
In the illustrated example, the long sides 61c and 61d have the same inclination angles θ5 and θ6 with respect to the tire width direction and are inclined at the same inclination angle, but they may be inclined at different inclination angles.

One of the second sipes 6c has a short side extending from an end e3 on one side of the long side 61c in the tire width direction (the WD1 side in the tire width direction in the illustrated example) toward the other second sipe 6d. 62c. As shown in FIG. 2B, the short side 62c extends toward the side where the one second sipe 6c and the other second sipe 6d face each other, forming a bending angle θ7 with the long side 61c.
The other second sipe 6d is arranged so as to approach the one second sipe 6c side from an end e4 on the other side of the long side 61d in the tire width direction (the WD2 side in the tire width direction in the illustrated example). It has a short side 62d extending to the . As shown in FIG. 2B, the short side 62d extends toward the side where the one second sipe 6c and the other second sipe 6d face each other, forming a bending angle θ8 with the long side 61d.
In the one second sipe 6c and the other second sipe 6d, one of the ends of the long sides 61c and 61d in the tire width direction is the side on which the short sides 62c and 62d are not provided. The short side does not extend from the end of the .

In the tire 10 of this embodiment, as shown in FIGS. 1 and 3, the first sipe unit 60A and the second sipe unit 60B are offset from each other in the tire width direction. The first sipe unit 60A and the second sipe unit 60B are out of phase with each other in the tire width direction when viewed along the tire circumferential direction in the developed view of the tread surface 1 (that is, at least one phase in the tire width direction). parts do not overlap).

The effects of the configuration of the tire of this embodiment will be described below.
The first sipe 6a on one side, the first sipe 6b on the other side, the second sipe 6c on one side, and the second sipe 6d on the other side each terminate in a land portion (in the block land portion 5 in this embodiment). This prevents formation of an open end of the sipe at the edge of the block land portion 5, and the end of each of the first sipe 6a, the first sipe 6b, the second sipe 6c and the second sipe 6d. Since the land portion remains connected around the portion, the block land portion rigidity can be increased compared to the case where the sipe is open to the edge portion of the block land portion. As a result, the deformation of the block land portion 5 is suppressed, the lifting of the contact surface is prevented, and the actual contact area with the road surface can be increased, so that the ice grip performance can be improved.
Further, in the present embodiment, the first sipes 6a and 6b, and the second sipes 6c and 6d are arranged to face each other in the tire circumferential direction, and are arranged on one side in the tire width direction. By having long sides 61a, 61b, 61c, and 61d that extend obliquely with respect to the tire width direction toward one side in the tire circumferential direction or the other side in the tire circumferential direction, the long sides The edge component not only exerts sufficient braking force and driving force in the tire circumferential direction (longitudinal direction), but also contributes to improvement of lateral grip performance in the tire width direction. In particular, by setting the inclination angles θ1, θ2, θ5, and θ6 to 45° or less, the tire width direction component of the long side of the sipe becomes equal to or greater than the tire circumferential direction component, which contributes to the improvement of braking/driving force, which is most important for safety. can do.

Moreover, in the present embodiment, the first sipes 6a and 6b have short sides 62a and 62b extending from the long sides 61a and 61b to the sides facing each other, and the second sipes 6c and 6d have the long sides 61c and 61b. It has short sides 62c and 62d extending from 61d to opposite sides. As a result, in the manufacturing process of the tire 10, when a thin metal plate (blade) is used to form a sipe in a mold, the short side of the blade serves as a support against bending deformation such that the long side of the blade collapses. , the bending stiffness of the blade can be greatly increased to improve durability and improve tire productivity.

In addition, in the present embodiment, the first sipe unit 60A and the second sipe unit 60B are offset from each other in the tire width direction. At this time, in the first sipe unit 60A and the second sipe unit 60B adjacent in the tire width direction, the long sides of the first sipe unit 60A and the second sipe unit 60B are inclined in opposite directions ( As described above, each of the long sides 61a and 61b is inclined upward to the right in the drawing so as to move toward the tire width direction WD1 side and toward the tire circumferential direction CD1 side. 61d are inclined downward to the right on the drawing so as to face the tire circumferential direction CD2 side as they go to the tire width direction WD1 side). Then, when there is an input in the tire circumferential direction to the block land portion, a force ( However, the first sipe unit 60A and the second sipe unit 60B support each other against the collapse deformation, and together, increase the rigidity of the block land portion and improve the ice grip performance. be able to.
Specifically, in the example of FIG. 3, for example, when there is an input in the tire circumferential direction from the tire circumferential direction CD1 side to the tire circumferential direction CD2 side to the block land portion 5, the land adjacent to the first sipe unit 60A A force that deforms the land portion adjacent to the second sipe unit 60B causes a force that causes the land portion to collapse toward the arrow X1 side. At this time, the land portion in the vicinity of the first sipe unit 60A and the land portion in the vicinity of the second sipe unit 60B have long sides that are slanted in opposite directions, so that they mutually support the collapse deformation. , the rigidity of the block land portion 5 can be increased.
In addition, when the long sides of the first sipe unit 60A and the second sipe unit 60B are not opposite to each other and are all inclined in the same direction, the land portion near the first sipe unit 60A and the second sipe unit 60B A land portion in the vicinity of the sipe unit 60B is subjected to a collapse deformation force in the same direction, and the land portion as a whole is deformed in the same direction. However, according to the configuration of this embodiment, such a reaction force can be offset.

As described above, according to the present embodiment, it is possible to increase the land rigidity (and thus the actual contact area) while maintaining the sipe density, that is, to achieve both the land rigidity and the high-density arrangement of the sipes. It can improve ice grip performance.

In the tire 10 of the present embodiment, as shown in FIGS. 1 and 3, the first sipe units 60A and the second sipe units 60B are arranged adjacent to each other in the tire circumferential direction. A first sipe unit row 7A and a second sipe unit row 7B are configured, and the first sipe unit row 7A and the second sipe unit row 7B are offset from each other in the tire width direction. is preferred.
In the tire 10 of the present embodiment, as shown in FIGS. 1 and 3, the first sipe units 60A and the second sipe units 60B are arranged adjacent to each other in the tire circumferential direction. A first sipe unit row 7A and a second sipe unit row 7B are configured. In FIG. 1 , a row of first sipe units 60A arranged adjacent to each other in the tire circumferential direction and arranged in the block land portion 53 (three units in the illustrated example), and a row of first sipe units 60A adjacent to each other in the tire circumferential direction A plurality (three in the illustrated example) of the second sipe units 60B are arranged as a typical example, and are shown as a first sipe unit row 7A and a second sipe unit row 7B, respectively. In the first sipe unit row 7A, the adjacent first sipe units 60A are separated from each other, and at least a part (all in this example) of each are arranged facing each other in the tire circumferential direction. In the second sipe unit row 7B, the adjacent second sipe units 60B are spaced apart from each other, and at least a part (all in this example) of each are arranged facing each other in the tire circumferential direction. there is Also, the first sipe unit row 7A and the second sipe unit row 7B are offset from each other in the tire width direction. As shown in FIGS. 1 and 3, the first sipe unit row 7A and the second sipe unit row 7B are arranged in the tire width direction when viewed along the tire circumferential direction in the developed view of the tread surface 1. They are arranged out of phase (that is, at least partially in the tire width direction do not overlap).
According to such a configuration, the land portion near the first sipe unit 60A that constitutes the first sipe unit row 7A and the land portion near the second sipe unit 60B that constitutes the second sipe unit row 7B are separated from each other. , and have oppositely slanted long sides, the block land portions 5 can support each other against falling deformation, and the rigidity of the block land portion 5 can be sufficiently increased. In addition, when the long sides of the first sipe units 60A forming the first sipe unit row 7A and the long sides of the second sipe units 60B forming the second sipe unit row 7B are all inclined in the same direction However, according to the configuration of the present embodiment, there is a risk that an unexpected force in the tire width direction may be generated as a reaction force due to deformation of the entire land portion in the same direction. Forces can be counterbalanced more effectively.

Preferred configurations, modifications, and the like of the tire 10 of the present embodiment will be described below.

In the tire 10 of this embodiment, the sipe depths of the one first sipe 6a, the other first sipe 6b, the one second sipe 6c, and the other second sipe 6d are not particularly limited. From the viewpoint of improving the performance more effectively, it is preferably 3 mm or more, and may be 10 mm or less, for example.

In the tire 10 of the present embodiment, in the first sipe unit 60A, the long sides and short sides of the first sipe 6a and the first sipe 6b preferably extend parallel to each other. As shown in FIG. 2A, the long side 61a and the long side 61b extend parallel to each other, and the short side 62a and the short side 62b extend parallel to each other. In addition, in the tire 10 of the present embodiment, the first sipe 6a on one side and the first sipe 6b on the other side are preferably offset in the tire width direction.
Further, in the tire 10 of the present embodiment, in the second sipe unit 60B, the long sides and the short sides of the one second sipe 6c and the other second sipe 6d preferably extend parallel to each other. As shown in FIG. 2B, the long side 61c and the long side 61d extend parallel to each other, and the short side 62c and the short side 62d extend parallel to each other. In addition, in the tire 10 of the present embodiment, the one second sipe 6c and the other second sipe 6d are preferably offset in the tire width direction.
In FIG. 2A, the first sipe 6a and the first sipe 6b are the same in the tire width direction when viewed along the tire circumferential direction in the developed view of the tread surface 1. The portions overlap with each other and are arranged out of phase in the tire width direction (that is, the portions in the tire width direction do not overlap). In FIG. 2B, the second sipe 6c and the second sipe 6d are partially separated from each other in the tire width direction when viewed along the tire circumferential direction in the developed view of the tread surface 1. While overlapping, the arrangement is such that the phase in the tire width direction is shifted (that is, a portion in the tire width direction does not overlap).
By arranging the long sides and short sides of the first sipe 6a and the first sipe 6b in parallel, and by arranging the long sides and short sides of the second sipe 6c and the second sipe 6d in parallel, the In each of the first sipe unit 60A and the second sipe unit 60B, the distance between the long sides and the short sides in the tire circumferential direction and the tire width direction can be made constant. When the first sipe unit 60A and the second sipe unit 60B are arranged adjacent to each other in the tire circumferential direction, the first sipe unit 60A and the second sipe unit 60B can be arranged without forming a useless space. It is easy to arrange them uniformly and at a high density.
In addition, the first sipe 6a on one side and the first sipe 6b on the other side, and the second sipe 6c on one side and the second sipe 6d on the other side are offset in the tire width direction, respectively, so that the first sipe unit 60A and the second sipe unit 60B are viewed along the tire circumferential direction in the developed view of the tread surface 1, each of the first sipe unit 60A and the second sipe unit 60B has one sipe and the other sipe. The sipes are present in a wider range in the tire width direction than in the case of not offsetting the . As a result, the braking force and driving force due to the edge component can be sufficiently exerted over a wider range in the tire width direction, and the ground contact pressure distribution of the block land portion 5 can be made uniform.

In the tire 10 of the present embodiment, the long sides 61a and 61b of the first sipe 6a and the first sipe 6b extend at inclination angles θ1 and θ2 with respect to the tire width direction of 0° or more and 45° or less, respectively. is preferably more than 0° and less than 45°. Further, the long sides 61c and 61d of the second sipe 6c and the second sipe 6d preferably extend at angles of inclination θ5 and θ6 with respect to the tire width direction of 0° or more and 45° or less, and more than 0° and 45°. It is more preferred to extend less than .
By setting each of the inclination angles θ1, θ2, θ5 and θ6 to 0° or more and 45° or less, braking force and driving force in the tire circumferential direction (longitudinal direction) due to the edge components of the long sides are sufficiently exerted. By setting the inclination angles θ1, θ2, θ5 and θ6 to more than 0° respectively, an edge effect can be obtained in the tire width direction, and the inclination angles θ1, θ2, θ5 and θ6 are each set to less than 45°. Thus, braking force and driving force in the tire circumferential direction (longitudinal direction) due to the edge component of the long side can be exhibited more sufficiently.

In the tire 10 of the present embodiment, in the first sipe unit 60A, one first sipe 6a and the other first sipe 6b are formed by a long side 61a and a short side 62a. and an angle θ3, which is the angle on the side where the other first sipe 6b faces, and The angle θ4 is preferably 90° or more. In addition, in the second sipe unit 60B, the one second sipe 6c and the other second sipe 6d are formed by the long side 61c and the short side 62c, respectively. The angle θ7, which is the angle on the side facing the sipes 6d, and the angle formed by the long side 61d and the short side 62d, which is the angle on the side facing the second sipes 6c on one side and the second sipes 6d on the other side. θ8 is preferably 90° or more.
According to such a configuration, in the manufacturing process of the tire 10, when a sipe is formed in a mold using a blade, the short side is more effective against bending deformation such that the long side of the blade collapses. It provides a strong support, increases the bending rigidity of the blade, improves durability more effectively, and improves the productivity of the tire. Further, by setting the angles θ3, θ4, θ7 and θ8 to 90° or more, the land portions near the vertex portions of the long sides and the short sides form sharp corners, that is, local low-rigidity portions. is prevented from being formed, deformation around the relevant portion is suppressed, the ground contact pressure step is prevented from becoming large, and braking force and driving force in the tire circumferential direction can be exhibited more effectively.
Also, the angles θ3, θ4, θ7 and θ8 are more preferably 150° or less. By setting the angles θ3, θ4, θ7, and θ8 to 150° or less, a moderate bend is formed between the short side and the long side compared to when the angles are 150° or more, and the blade forms a sipe during tire manufacturing. durability can be improved.

Further, in the tire 10 of the present embodiment, as shown in FIGS. 1, 2A, and 2B, in the first sipe unit 60A, one first sipe 6a and the other first sipe 6b each have a short side 62a. and 62b extend along the tire circumferential direction, and in the second sipe unit 60B, short sides 62c and 62d of the one second sipe 6c and the other second sipe 6d extend along the tire circumferential direction, respectively. is preferred. It should be noted that "extending along the tire circumferential direction" means a case where the tire is parallel to the tire circumferential direction, or a case where the tire is inclined at an extremely low angle with respect to the tire circumferential direction (for example, an inclination angle of 5 with respect to the tire circumferential direction). ° or less). According to such a configuration, the sipes capable of exhibiting braking force and driving force can be arranged more efficiently with respect to the input in the tire circumferential direction, and the direction of the short side is the input direction of the braking/driving force. , the block land portion is not divided with respect to the input direction, and the decrease in rigidity of the land portion around the short side can be more effectively suppressed. In addition, according to such a configuration, the water accumulated on the long sides of the sipes by removing the water film on the surface of the ice is removed from the short sides of the sipes extending along the tire circumferential direction provided at the ends of the long sides. It can be efficiently guided in the tire circumferential direction, which is the slipping direction during braking, to promote drainage.
In the case where the short sides 62a and 62b extend along the tire circumferential direction, an appropriate bend is formed between the short sides and the long sides to effectively improve the durability of the blades that form the sipes during tire manufacturing. From the viewpoint of improving the braking force and driving force in the tire circumferential direction (longitudinal direction) due to the edge component of the long side, the angles θ3 and θ4 are more than 90° and 135° ° or less. Similarly, when the short sides 62c and 62d extend along the tire circumferential direction, moderate bends are formed between the short sides and the long sides, and the durability of the blades that form the sipes during tire manufacturing is improved more effectively. from the viewpoint of sufficiently exerting the braking force and driving force in the tire circumferential direction (front-rear direction) by the edge component of the long side, the angles θ7 and θ8 are more than 90°. It is preferably 135° or less. As described above, by setting the inclination angle of the long side to the tire width direction to 0 to 45°, the maximum effect can be exhibited in terms of braking and driving performance, which is most important for safety. In order to make the short sides substantially along the circumferential direction while maintaining this angle, the bending angle between the long sides and the short sides must be 90 to 135 degrees. In addition, in the tire 10 of the present embodiment, for example, the inclination angles θ1 and θ2 of the long sides 61a and 61b are 30°, and the angles θ3 and θ4 are 120°.

In the tire 10 of the present embodiment, as shown in FIGS. 1, 2A, and 2B, in the first sipe unit 60A, one first sipe 6a and the other first sipe 6b are congruent with each other, and the second In the sipe unit 60B, one second sipe 6c and the other second sipe 6d are preferably congruent. According to such a configuration, in the block land portion 5, when a plurality of the first sipe units 60A and the second sipe units 60B are arranged adjacent to each other in the tire circumferential direction, they are arranged uniformly and at a high density. Cheap.
For the same reason, in the tire 10 of the present embodiment, as shown in FIG. , are all preferably congruent with each other.
In addition, as shown in FIGS. 1 and 3, even if all the sipes included in the first sipe unit row 7A are congruent and all the sipes included in the second sipe unit row 7B are congruent, Well, all the sipes included in the first sipe unit row 7A and the second sipe unit row 7B may be congruent.
Here, "congruent" means congruent including mirror images, and means that they completely overlap each other due to parallel movement, rotational movement and/or line-symmetrical movement when viewed from the tread surface.

In the tire 10 of the present embodiment, in the first sipe unit 60A, one first sipe 6a and the other first sipe 6b each have a long side 61a with respect to the length along the extending direction of the short sides 62a and 62b. and 61b along the extending direction is 1 to 15, and in the second sipe unit 60B, one second sipe 6c and the other second sipe 6d have short sides 62c and 62d, respectively. The ratio of the length along the extending direction of the long sides 61c and 61d to the length along the extending direction is preferably 1-15. In FIG. 2A, the ratio of the length L2 along the extending direction of the long side 61a to the length L1 along the extending direction of the short side 62a is 1 to 15, and the length along the extending direction of the short side 62b is The ratio of the length L4 along the extending direction of the long side 61b to the length L3 is 1 to 15, and in FIG. The ratio of the length L8 along the extending direction is 1 to 15, and the ratio of the length L10 along the extending direction of the long side 61d to the length L9 along the extending direction of the short side 62d is 1 to 15. is preferred.
According to such a configuration, since the ratio of the length of the long side to the short side is 1 or more, it is possible to suppress an excessive decrease in the sipe density or the rigidity of the land portion, and is 15 or less, it is possible to improve the durability of the blade that forms the sipe during tire manufacturing.

In the tire 10 of the present embodiment, the lengths L2 and L4 along the extending direction of the long sides 61a and 61b in the first sipe unit 60A and the extension of the long sides 61c and 61d in the second sipe unit 60B The values of the lengths L8 and L10 along the direction are not particularly limited, but they allow the viewpoint of maintaining the rigidity of the block land portion 5 while sufficiently exhibiting the grip performance on ice of the tire and application to various tires. From the point of view, it is preferable to set each to 3 to 15 mm.

Further, in the tire 10 of the present embodiment, the lengths L1 and L3 along the extending direction of the short sides 62a and 62b in the first sipe unit 60A and the extension of the short sides 62c and 62d in the second sipe unit 60B The values of the lengths L7 and L9 along the direction are also not particularly limited, but from the viewpoint of more effectively improving the durability of the blades that form the sipes during tire manufacturing, they are set to 1 mm or more, and the long side 61a and 61b along the extending direction, and lengths L8 and L10 along the extending direction of the long sides 61c and 61d.

Further, in the tire 10 of the present embodiment, the first sipe unit 60A has a ratio of the tire circumferential length L6 along the tire circumferential direction to the tire width direction length L5 along the tire width direction from 0.1 to 2. .6, and in the second sipe unit 60B, the ratio of the tire circumferential length L12 along the tire circumferential direction to the tire width direction length L11 along the tire width direction is 0.1 to 2.6. is preferred.
Here, the "tire width direction length along the tire width direction" is the tire width direction length along a straight line parallel to the tire width direction. Refers to the distance between the edge in the width direction WD2 side and the edge in the tire width direction WD1 side of the center line C2 of the first sipe 6b. side edge and the edge on the tire width direction WD2 side of the center line C4 of the second sipe 6d. "The tire circumferential direction length along the tire circumferential direction" is the tire circumferential direction length along a straight line parallel to the tire circumferential direction. side and the end of the center line C2 of the first sipe 6b on the CD2 side in the tire circumferential direction. and the end of the center line C4 of the second sipe 6d on the tire circumferential direction CD2 side. When the value of the ratio is 0.1 or more, the circumferential distance between the sipes does not become too narrow, and the block rigidity can be sufficiently secured. Further, when the value of the ratio is 2.6 or less, the inclination angles θ1 and θ2 of the long sides 61a and 61b become excessive, or the tire width direction length of the long sides 61a and 61b becomes too short. Therefore, a more sufficient effect on braking/driving force can be obtained.

In the tire 10 of the present embodiment, as shown in FIG. 3, in a plurality of (three in the illustrated example) first sipe units 60A in the first sipe unit row 7A, a plurality of (in this example, all The short side 62a of one first sipe 6a extends on the same straight line along the tire circumferential direction (in FIG. 3, on the imaginary line Y1 extending along the tire circumferential direction), and has a plurality of (in this example, on the imaginary line Y1 extending along the tire circumferential direction) , all of the short sides 62b of the other first sipe 6b extend on the same straight line along the tire circumferential direction (in FIG. 3, on the imaginary line Y2 extending along the tire circumferential direction), and the second sipe unit row In the plurality of (in this example, three) second sipe units 60B in 7B, the short sides 62d of the plurality of (in this example, all) other second sipes 6d are aligned along the tire circumferential direction. While extending on a straight line (in FIG. 3, on a virtual line Y2 extending along the tire circumferential direction), the short side 62c of one of the plurality of (in this example, all) second sipes 6c extends along the tire circumferential direction. It is preferable to extend on the same straight line (in FIG. 3, on the imaginary line Y3 extending along the tire circumferential direction).
According to such a configuration, the phases in the tire width direction are aligned in each of the first sipe units 60A and the second sipe units 60B that are arranged adjacent to each other in the tire circumferential direction. 5, it is easy to arrange multiple first sipe units 60A and second sipe units 60B uniformly and at high density without forming useless voids.

In addition, in the tire 10 of the present embodiment, in each of the first sipe unit row 7A and the second sipe unit row 7B, the first sipe unit 60A and the second sipe unit 60B are arranged at regular intervals around the tire circumference. It is preferable that a plurality of them be arranged adjacent to each other in the direction. Regarding the spacing between the first sipe units 60A and the spacing between the second sipe units 60B, the configurations of the first sipe unit row 7A and the second sipe unit row 7B will be described below using the first sipe unit row 7A as a typical example. .
In the example shown in FIG. 3, all long sides included in the first sipe unit row 7A extend parallel to each other. The other first sipe 6b of the first sipe unit 60A is arranged at a position shifted in phase from the one first sipe 6a by an offset s in the tire width direction and by an offset q in the tire circumferential direction. there is
In the first sipe unit row 7A, the first sipe units 60A are repeatedly arranged at a pitch p in the tire circumferential direction. Here, assuming that the distance in the tire circumferential direction between the first sipe units 60A adjacent in the tire circumferential direction is the inter-unit distance r, the inter-unit distance r is expressed by r=pq. In particular, the pitch p between the first sipe units 60A that are adjacent in the tire circumferential direction and the tire circumferential offset q between the first sipes 6a and the first sipes 6b that constitute the first sipe units 60A are q=p/2. , r=q (unit-to-unit distance r=tire circumferential offset q), and all sipes are arranged at regular intervals in the circumferential direction within the first sipe unit 60A and between the first sipe units 60A. Therefore, q is preferably in the range of (p/2)×0.8 to (p/2)×1.2, and more preferably q is p/2. Directional sipe density can be uniformed. Therefore, the contact surface of the block land portion 5 can be brought into contact with the road surface more uniformly, and the distribution of the contact pressure applied to the contact surface of the block land portion 5 can be made uniform, and the contact area of the tire 10 can be increased. be able to.

Further, in the tire 10 of the present embodiment, in the first sipe unit row 7A and the second sipe unit row 7B, a plurality of the first sipe units 60A and the second sipe units 60B are arranged at regular intervals in the tire circumferential direction. It is preferable that As shown in FIG. 3, the first sipe unit row 7A (more specifically, the first sipe unit 60A in the first sipe unit 7A) and the second sipe unit row 7B (more specifically, the second The second sipe units 60B) in the sipe unit row 7B are arranged at positions shifted in phase from each other by an offset u in the tire circumferential direction. When the offset u and the pitch p in the first sipe unit 60A adjacent in the tire circumferential direction (the pitch in the second sipe unit 60B adjacent in the tire circumferential direction is also the pitch p) are u=p/2, In the first sipe unit row 7A and the second sipe unit row 7B, the first sipe units 60A and the second sipe units 60B are arranged at regular intervals in the tire circumferential direction. For this reason, the offset u is preferably in the range of (p/2)×0.8 to (p/2)×1.2, and more preferably u is p/2. Sipe density in the circumferential direction can be made uniform. Therefore, the contact surface of the block land portion 5 can be brought into contact with the road surface more uniformly, and the distribution of the contact pressure applied to the contact surface of the block land portion 5 can be made uniform, and the contact area of the tire 10 can be increased. be able to.

Here, in FIGS. 3 and 4, v denotes a tire width direction interval between the first sipe unit row 7A and the second sipe unit row 7B that are adjacent to each other in the tire width direction.
The offset u in the tire circumferential direction and the interval v in the tire width direction may each be set to an arbitrary value.

Here, as described above, when the offset in the tire width direction between the pair of first sipes and the pair of second sipes in each sipe unit is s (s>0), the interval v is -s to s is preferred. It should be noted that the fact that the interval v is a negative value (for example, -s) means that the first sipe unit row 7A and the second sipe unit row 7B are v in the tire width direction when viewed along the tire circumferential direction. means a state in which they overlap by the absolute value of
When v is -s or more, the land portion rigidity can be sufficiently secured without the sipes arranged in the land portion becoming too dense. It is possible to secure a continuous region and thus more sufficient rigidity of the land portion, and by making v equal to or less than s, it is possible to secure a sufficient sipe density in the land portion.
In particular, when v=0, adjacent sipe unit rows are arranged continuously in the tire width direction, so it is possible to prevent a blank region in which no sipe exists between the sipe unit rows. In the case of v=0, the short sides of adjacent sipe unit rows can be arranged in a line along the same straight line along the tire circumferential direction. increase significantly. Therefore, it is particularly preferable to set v=0.

FIG. 4 is a diagram for explaining another arrangement of the first sipe unit 60A and the second sipe unit 60B from that in FIG.
In each sipe unit, one (or the other) sipe short side end in the tire circumferential direction is more likely than the other (or one) sipe long side end in the tire circumferential direction with respect to the input direction in the tire circumferential direction. , preferably not protruding. More specifically, for example, in FIG. 4, the end E1 of the short side 62d of the second sipe 6d on the side of the tire circumferential direction CD1 is closer to the tire circumferential direction CD1 than the end E2 of the long side 61c of the second sipe 6c on the side of the tire circumferential direction CD1. Although it protrudes in the tire circumferential direction CD1 side, when there is an input from the tire circumferential direction CD1 side to the tire circumferential direction CD2 side, the area surrounded by the dotted line in FIG. From the viewpoint of improvement, it is preferable that the end E1 does not protrude further toward the tire circumferential direction CD1 than the end E2.

In the tire 10 of the present embodiment, more preferably, as shown in FIG. 3, in the first sipe unit row 7A and the second sipe unit row 7B, which are adjacent in the tire width direction, , the second sipe unit row 7B side, which is offset in the tire width direction, of the short side 62a of one first sipe 6a or the short side 62b of the other first sipe 6b of the plurality of first sipe units 60A and the short side 62c of one second sipe 6c or the short side 62d of the other second sipe 6d of the plurality of second sipe units 60B in the second sipe unit row 7B, in the tire width direction The short side on the side of the first sipe unit row 7A, which is offset from the rear edge, extends on the same straight line along the tire circumferential direction. In the example of FIG. 3, among the short sides included in the first sipe unit 60A, the short side 62b on the side of the second sipe unit row 7B, and the short sides included in the second sipe unit 60B, the first sipe unit row The short side 62d on the 7A side extends on the same straight line along the tire circumferential direction (in FIG. 3, on the imaginary line Y2 extending along the tire circumferential direction). According to such a configuration, the interval v in the tire width direction between the first sipe unit row 7A and the second sipe unit row 7B becomes v=0, and the first sipe unit 60A and the second sipe unit 60B are In the developed view of the tread surface 1, when viewed along the tire circumferential direction, the distance from the end of the first sipe unit row 7A on the side of the tire width direction WD2 to the end of the second sipe unit row 7B on the side of the tire width direction WD1 The sipes are present over the entire width in the tire width direction. As a result, the first sipe unit 60A and the second sipe unit 60B are integrated, and in the entire width of the tire width direction region where the first sipe unit row 7A and the second sipe unit row 7B are arranged, the braking force due to the edge component is obtained. In addition, the driving force can be sufficiently exerted, and the ground contact pressure distribution of the block land portion 5 can be made uniform. In addition, it is possible to more sufficiently secure the area where the land portions are continuous around the short sides.

In the tire 10 of this embodiment, the number and density of the first sipe units 60A and the second sipe units 60B arranged in each block land portion 5 are not particularly limited. As mentioned above, in the example shown in FIG. are each arranged with three first sipe units 60A and three second sipe units 60B.

One first sipe 6a and the other first sipe 6b that constitute the first sipe unit 60A, and one second sipe 6c and the other that constitute the second sipe unit 60B, which are arranged in the block land portion 5 The total number of the second sipes 6d may be determined, for example, based on the sipe density SD described below.

A method for calculating the sipe density SD will be described below. FIG. 5 is an enlarged view of one of the block land portions 53 in FIG. As shown in FIG. 5, when the block land portion 53 in FIG. The total number of sipes 6d is n (pieces), and the tire width direction length of each of the first sipe 6a, the first sipe 6b, the second sipe 6c, and the second sipe 6d is d (mm) (in FIG. 5, the sipe The length of 6a in the tire width direction is indicated as d), and the sipe depth of sipes 6a, 6b, 6c, and 6d is h (mm), dxh is, for example, 150 (mm ² ) or less. can do. Further, when the maximum length of the block land portion 5 in the tire width direction is BW (mm), the equivalent number of sipes N is expressed as d×n/BW. Here, the equivalent number of sipes N means the number of transverse sipes provided so as to completely cross the block land portion 5 from the first sipe 6a, the first sipe 6b, the second sipe 6c, and the second sipe 6d of the present embodiment. This is the number when converted to (equivalent sipe). Furthermore, if BL (mm) is the equivalent land portion tire circumferential length obtained by dividing the outer contour area (mm ² ) of the block land portion 5 by the BW (mm), the average sipe spacing is BL/(N+1). expressed. Here, the average sipe interval is the tire circumference in the block land portion 5 of the equivalent sipe when the first sipe 6a, the first sipe 6b, the second sipe 6c, and the second sipe 6d of the present embodiment are converted to equivalent sipes. is the spacing in the direction. The sipe density SD is expressed by the following formula as the reciprocal of the average sipe spacing.
SD=(N+1)/BL=((d×n/BW)+1)/BL (Formula 1)
The total number n of the sipes in the block land portion, the tire width direction length d of each of the sipes, the maximum length BW of the block land portion in the tire width direction, and the outer contour area of the block land portion are the tread tread surface. It is the value measured in the developed view. The "outer contour area" of the block land part refers to the area surrounded by the outer contour of the block land part in the developed view of the tread surface. means the area that does not exclude the area of the sipe, small hole, fine groove, etc., even if is arranged.

For example, in the block land portion 5, a plurality of first sipes 6a, 6b, 6c and 6d may be arranged such that the sipe density SD is 0.15 or more. . As a result, the sipe density can be increased while suppressing a decrease in the rigidity of the land portion, and the ice grip performance of the tire can be more effectively improved.

Examples of the present invention will be described below, but the present invention is not limited thereto.

For test tires (Comparative Examples 1 to 3 and Examples 1 to 3) 1 to 6, the effect of suppressing lifting on the ground contact surface was calculated by the finite element method (FEM). Each test tire has block land portions shown in Table 1 and FIGS. 6(a) to (f) on the tread surface. The results of the comparative examples and examples shown in Table 1 and FIG. 6 are shown graphically in FIG. As shown in FIG. 7, the horizontal axis of the graph is the block stiffness (N/mm), and the vertical axis of the graph is the actual ground contact area (mm ² ) during shearing.
Predictive calculations by FEM were performed under the condition of applying a vertical load obtained by multiplying the outer contour area of the block land portion by the standard ground contact pressure of a passenger car tire of 230 kPa, and the block rigidity and ground contact area were evaluated.
For the block rigidity, the shear input value in the same direction when the lateral displacement in the tire circumferential direction is 1 mm is obtained. , was obtained from the residual ground contact area in a state where partial lifting occurred.
According to the results of FIG. 7, even if the number of sipes and thus the sipe density are the same (between Comparative Example 1 and Example 1, Comparative Example 2 and Example 2, and Comparative Example 3 and Example 3) , the block rigidity and the actual ground contact area are greater in the example, and the effect of suppressing the lifting of the contact surface of the block land portion is greater, so that the ice grip performance can be improved.

The pneumatic tire according to the present invention can be used for any type of pneumatic tire, but is preferably a passenger car tire or a truck or bus tire, more preferably a winter passenger car tire or a winter tire. It can be used for tires for trucks and buses.

1: Tread tread 2, 2a, 2b, 2c, 2d: Circumferential main grooves 3, 3a, 3b, 3c, 3d, 3e: Land portions 4, 41, 42, 43, 44, 45: Lateral grooves 5 , 51, 52, 53, 54, 55: block land portion, 6a: first sipe (first sipe on one side), 6b: first sipe (first sipe on the other side), 6c: second sipe (first sipe on one side) 2 sipes), 6d: second sipe (the other second sipe), 7A: first sipe unit row, 7B: second sipe unit row, 10: tire, 60A: first sipe unit, 60B: second sipe unit , 61a, 61b, 61c, 61d: long sides 62a, 62b, 62c, 62d: short sides e1, e2, e3, e4: edges E1, E2: edges C1, C2: center lines WD1, WD2: Tire width direction CD1, CD2: Tire circumferential direction TE: Tread edge Y1, Y2, Y3: Virtual line d: Tire width direction length of sipe s: Tire width direction offset p: Tire circumferential direction sipe unit pitch q: tire circumferential offset u: tire circumferential offset between adjacent sipe unit rows in the tire width direction v: tire width direction spacing between adjacent sipe unit rows in the tire width direction r: Unit-to-unit distance between adjacent sipe units in the tire circumferential direction

Claims (10)

A tire having at least one land on the tread surface of the tire,
A first sipe unit comprising a pair of first sipes and a second sipe unit comprising a pair of second sipes are arranged on at least one of the land portions,
Both ends of the first sipe and the second sipe terminate within the land portion,
One first sipe and the other first sipe, which constitute the pair of first sipes in the first sipe unit, are arranged to face each other in the tire circumferential direction and are arranged on one side in the tire width direction. Having a long side that extends obliquely with respect to the tire width direction so as to go toward one side in the tire circumferential direction as it goes,
The one first sipe has a short side extending from one end of the long side in the tire width direction to approach the other first sipe,
The other first sipe has a short side extending from the other end of the long side in the tire width direction so as to approach the one first sipe,
One second sipe and the other second sipe, which constitute the pair of second sipes in the second sipe unit, are arranged facing each other in the tire circumferential direction and each have a length extending in the tire width direction. has an edge,
The one second sipe has a short side extending from one end of the long side in the tire width direction to approach the other second sipe,
The other second sipe has a short side extending from the other end of the long side in the tire width direction so as to approach the one second sipe,
A tire, wherein the first sipe unit and the second sipe unit are offset from each other in the tire width direction. A plurality of the first sipe units and the second sipe units are arranged adjacent to each other in the tire circumferential direction to form a first sipe unit row and a second sipe unit row, respectively. 2. The tire according to claim 1, wherein said first sipe unit row and said second sipe unit row are offset from each other in the tire width direction. In the plurality of first sipe units in the first sipe unit row, the short sides of the one of the plurality of first sipes extend on the same straight line along the tire circumferential direction, The short sides of the first sipe extend on the same straight line along the tire circumferential direction,
In the plurality of second sipe units in the second sipe unit row, the short sides of the one of the plurality of second sipes extend on the same straight line along the tire circumferential direction, The tire according to claim 2, wherein the short sides of the second sipe extend on the same straight line along the tire circumferential direction. In the first sipe unit row and the second sipe unit row, which are adjacent in the tire width direction,
Of the plurality of first sipe units in the first sipe unit row, the second sipe unit row side of the short side of the one first sipe or the short side of the other first sipe the short side positioned at
Of the plurality of second sipe units in the second sipe unit row, of the short side of the one second sipe or the short side of the other second sipe, the first sipe unit row side 4. The tire according to claim 2 or 3, wherein the short sides arranged in the direction of the tire extend on the same straight line along the tire circumferential direction. In the first sipe unit, each of the one first sipe and the other first sipe has the short side extending along the tire circumferential direction,
The said 2nd sipe unit WHEREIN: Said one 2nd sipe and said other 2nd sipe are each described in any one of Claims 1, 2, and 4 with which said short side is extended along a tire peripheral direction. tires. In the first sipe unit, the one first sipe and the other first sipe have the long sides and the short sides extending parallel to each other, and the one first sipe and the other first sipe extend parallel to each other. 2 sipes are arranged offset in the tire width direction,
In the second sipe unit, the one second sipe and the other second sipe have the long sides and the short sides extending parallel to each other, and the one second sipe and the other second sipe extend parallel to each other. The tire according to any one of claims 1 to 5, wherein the two sipes are offset in the tire width direction. In the first sipe unit, the one first sipe and the other first sipe are formed by the long side and the short side, and the one first sipe and the other first sipe are opposed to each other. The angle on the side to do is 90 ° or more,
In the second sipe unit, the one second sipe and the other second sipe are formed by the long side and the short side, and the one second sipe and the other second sipe are opposed to each other. The tire according to any one of claims 1 to 6, wherein the angle of the facing side is 90° or more. In the first sipe unit, the one first sipe and the other first sipe are congruent with each other,
The tire according to any one of claims 1 to 7, wherein in the second sipe unit, the one second sipe and the other second sipe are congruent with each other. In the first sipe unit, each of the one first sipe and the other first sipe has a ratio of a length along the extending direction of the long side to a length along the extending direction of the short side. is 1 to 15,
In the second sipe unit, the one second sipe and the other second sipe each have a ratio of length along the extending direction of the long side to length along the extending direction of the short side. is 1-15. The first sipe unit has a ratio of a tire circumferential length along the tire circumferential direction to a tire width direction length along the tire width direction of 0.1 to 2.6,
The second sipe unit according to any one of claims 1 to 9, wherein the ratio of the tire circumferential length along the tire circumferential direction to the tire width direction length along the tire width direction is 0.1 to 2.6. or the tire described in paragraph 1.

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