Patent Description:
International Publication No. <CIT> suggests a tire in which a plurality of closed sipes are aligned in the tire axial direction at a tread portion. The plurality of closed sipes are disposed so as to overlap each other in the tire axial direction and the tire circumferential direction. In the tire, on-ice braking/driving performance and braking performance are expected to be enhanced by such arrangement of the closed sipes.

In the above-described tire, the closed sipes are repeatedly opened and closed according to the tread portion being brought into contact with the ground and released, so that uneven wear such as heel-and-toe wear tends to be easily generated around the closed sipes.

The present invention has been made in view of the aforementioned problems, and a main object of the present invention is to provide a tire that allows reduction of uneven wear such as heel-and-toe wear around a plurality of closed sipes.

Related technology is known from <CIT> which discloses a tire featuring sipes cut into the surface of the tread, located on a block and/or rib, wherein the sipes are closed at both ends and include one or more bent sections on the tread surface, and wheein the bends are formed along ridge lines that extend from the bent sections toward the bottom of the sipes.

More related tires are known from <CIT>, <CIT>, and <CIT>.

The present invention is directed to a tire that includes a tread portion as set out in the appended claims. The tread portion includes a land portion. A plurality of closed sipes each having a width of not greater than <NUM> are aligned in a tire axial direction in the land portion. Each of the closed sipes includes a sipe bottom, a first end and a second end in the tire axial direction, a first sipe piece extending on the first end side at a first angle relative to the tire axial direction, a second sipe piece extending on the second end side at a second angle relative to the tire axial direction, a third sipe piece continuous with the first sipe piece and the second sipe piece at a first intersecting portion and a second intersecting portion, respectively, the third sipe piece extending at a third angle different from the first angle and the second angle relative to the tire axial direction, and at least one tie bar formed by the sipe bottom locally protruding outward in a tire radial direction. The closed sipes aligned in the tire axial direction overlap each other in the tire axial direction and a tire circumferential direction. The tie bar includes a first tie bar disposed in the first sipe piece. A center, in a sipe length direction, of the first tie bar is disposed closer to the first intersecting portion than a center, in a length direction, of the first sipe piece is. A distance from an end of the first tie bar on the first intersecting portion side to the first intersecting portion is not greater than <NUM>% of a length of the first sipe piece.

The tire of the present invention has the above-described structure and thus allows reduction of uneven wear such as heel-and-toe wear around the plurality of closed sipes.

<FIG> is a transverse cross-sectional view of a tread portion <NUM> of a tire <NUM> of the present embodiment. <FIG> is a meridian cross-sectional view including the tire rotation axis of the tire <NUM> in a standardized state. The tire <NUM> of the present embodiment is used as, for example, a pneumatic tire for a passenger car. The present invention may be applied to, for example, light truck tires and van tires on which high load acts during running.

In the case of a pneumatic tire for which various standards are defined, the "standardized state" represents a state where a tire is mounted on a standardized rim and is inflated to a standardized internal pressure and no load is applied to the tire. In the case of non-pneumatic tires and tires for which various standards are not defined, the standardized state represents a standard use state which corresponds to a purpose of use of the tire and in which no load is applied to the tire. In the description herein, unless otherwise specified, dimensions and the like of components of the tire are represented as values measured in the standardized state.

In a standard system including a standard on which the tire is based, the "standardized rim" represents a rim that is defined by the standard for each tire, and is, for example, "standard rim" in the JATMA standard, "Design Rim" in the TRA standard, or "Measuring Rim" in the ETRTO standard.

In a standard system including a standard on which the tire is based, the "standardized internal pressure" represents an air pressure that is defined by the standard for each tire, and is "maximum air pressure" in the JATMA standard, the maximum value recited in the table "TIRE LOAD LIMITS AT VARIOUS COLD INFLATION PRESSURES" in the TRA standard, or "INFLATION PRESSURE" in the ETRTO standard.

As shown in <FIG>, the tread portion <NUM> includes, for example, a plurality of main grooves <NUM> extending continuously in the tire circumferential direction, and a plurality of land portions <NUM> demarcated by the plurality of main grooves <NUM>.

<FIG> is an enlarged plan view of the land portion <NUM>. As shown in <FIG>, in the present embodiment, the land portion <NUM> is, for example, formed as a block array including a plurality of blocks <NUM> in the tire circumferential direction. The blocks <NUM> are demarcated between a plurality of lateral grooves <NUM> extending across the land portion <NUM> in the tire axial direction. In the present invention, the land portion <NUM> is not limited to such a structure, and may be, for example, a rib extending continuously in the tire circumferential direction.

In the description herein, in some of the figures, a first side A1 in the tire circumferential direction, a second side A2 opposite to the first side A1 in the tire circumferential direction, a first side B1 in the tire axial direction, and a second side B2 opposite to the first side B1 in the tire axial direction are indicated by arrows. Unless otherwise specified, in figures illustrating the land portion <NUM> in a planar view, the upward direction corresponds to the first side A1 in the tire circumferential direction, the downward direction corresponds to the second side A2 in the tire circumferential direction, the leftward direction corresponds to the first side B1 in the tire axial direction, and the rightward direction corresponds to the second side B2 in the tire axial direction.

In the land portion <NUM>, a plurality of closed sipes <NUM> are aligned in the tire axial direction. In the present embodiment, a plurality of sipe groups <NUM> in each of which the closed sipes <NUM> are aligned are disposed in one block <NUM>. One sipe group <NUM> is, for example, formed of three to seven closed sipes <NUM>.

In the description herein, the "sipe" represents a cut portion which has a minute width such that a width between two sipe walls opposing each other is not greater than <NUM>. In a preferable mode, in the present embodiment, the width of the closed sipe <NUM> is not greater than <NUM>. In the description herein, the "closed sipe" represents a sipe that has both ends terminating in the land portion <NUM>. In the present embodiment, the sipe group <NUM> disposed in the block <NUM> is merely formed of the closed sipes <NUM>. In other words, no sipe is connected to the edge of the block <NUM>. However, the present invention is not limited to such a structure. A sipe disposed near the edge of the block <NUM> may be a non-closed sipe which has one end opened at the edge.

<FIG> is an enlarged plan view of the closed sipe <NUM> of the present embodiment. <FIG> is a transparent perspective view of an example of the inside of the closed sipe <NUM> of the present embodiment. In the description herein, in the transparent perspective view like <FIG>, the edge of the closed sipe <NUM> on the tread surface is indicated by a solid line, and the shape of the inside of the closed sipe <NUM> is indicated by dashed lines. As shown in <FIG> and <FIG>, each of the closed sipes <NUM> includes a sipe bottom 8d, a first end 8a and a second end 8b in the tire axial direction, a first sipe piece <NUM>, a second sipe piece <NUM>, a third sipe piece <NUM>, and at least one tie bar <NUM>.

As shown in <FIG>, in the present embodiment, the first end 8a is an end of the closed sipe <NUM> on the first side B1 in the tire axial direction. The second end 8b is an end of the closed sipe <NUM> on the second side B2 in the tire axial direction. The first sipe piece <NUM> extends in the tire axial direction on the first end 8a side relative to the third sipe piece <NUM>. The first sipe piece <NUM> extends at a first angle θ1 relative to the tire axial direction.

The second sipe piece <NUM> extends in the tire axial direction on the second end 8b side relative to the third sipe piece <NUM>. The second sipe piece <NUM> extends at a second angle θ2 relative to the tire axial direction. The third sipe piece <NUM> is continuous with the first sipe piece <NUM> and the second sipe piece <NUM> at a first intersecting portion <NUM> and a second intersecting portion <NUM>, respectively, and extends at a third angle θ3 different from the first angle θ1 and the second angle θ2 relative to the tire axial direction.

In such arrangement, in the closed sipe <NUM> of the present embodiment, the first sipe piece <NUM> is disposed on the first side A1 relative to the second sipe piece <NUM> in the tire circumferential direction, and on the first side B1 relative thereto in the tire axial direction. In the present embodiment, the first sipe piece <NUM> is continuous with the first side A1 of the third sipe piece <NUM> in the tire circumferential direction. The second sipe piece <NUM> is continuous with the second side A2 of the third sipe piece <NUM> in the tire circumferential direction.

In the present embodiment, each of the first sipe piece <NUM>, the second sipe piece <NUM>, and the third sipe piece <NUM> linearly extends. However, the present invention is not limited to such a structure. As long as a region in which the sipe is bent is formed at the first intersecting portion <NUM> and the second intersecting portion <NUM>, the sipe pieces may be curved or bent with a wavy amplitude. In the description herein, an angle of each portion in the closed sipe <NUM> is measured at the center line (line that equally divides the sipe opening width) of the sipe in a planar view (hereinafter, referred to as "tread planar view") in which the tread portion <NUM> is developed into a plane. Each of the first angle θ1 and the second angle θ2 described above is, for example, not greater than <NUM>° and preferably not greater than <NUM>°. In the present embodiment, the first angle θ1 and the second angle θ2 are equal to each other, and the first sipe piece <NUM> and the second sipe piece <NUM> extend parallel to the tire axial direction. The third angle θ3 is, for example, greater than each of the first angle θ1 and the second angle θ2 and is, for example, <NUM> to <NUM>°. The other sipe pieces included in the closed sipe <NUM> of the present embodiment will be described below.

As shown in <FIG>, the tie bar <NUM> is a region in which the sipe walls opposing each other are partially connected, and, thus, the sipe bottom 8d locally protrudes outward in the tire radial direction. In <FIG>, the tie bar <NUM> is indicated as a void. However, the tie bar <NUM> is formed of a rubber member in which the sipe bottom 8d protrudes, in practice. The tie bar <NUM> is expected to allow deformation of the closed sipe <NUM> to be inhibited, and allow uneven wear around the closed sipe <NUM> to be reduced. However, in a conventional embodiment, the tie bar <NUM> is disposed at the center portion of the first sipe piece <NUM> or the center portion of the second sipe piece <NUM>, and deformation of the closed sipes <NUM> thus tends to be insufficiently inhibited.

As shown in <FIG>, the closed sipes <NUM> aligned in the tire axial direction overlap each other in the tire axial direction and the tire circumferential direction. "The closed sipes <NUM> overlap each other in the tire axial direction" means that an imaginary region obtained by extending one closed sipe <NUM> in parallel to the tire circumferential direction overlaps the closed sipe <NUM> adjacent to the one closed sipe <NUM>. "The closed sipes <NUM> overlap each other in the tire circumferential direction" means that an imaginary region obtained by extending one closed sipe <NUM> in parallel to the tire axial direction overlaps the closed sipe <NUM> adjacent to the one closed sipe <NUM>. Such arrangement of the sipes can enhance on-ice performance whereas uneven wear tends to be caused around the sipes.

As shown in <FIG>, the tie bar <NUM> includes a first tie bar <NUM> disposed in the first sipe piece <NUM>. As shown in <FIG>, the center 21c, in the sipe length direction, of the first tie bar <NUM> is disposed closer to the first intersecting portion <NUM> than the center 11c, in the length direction, of the first sipe piece <NUM> is. A distance L2 from an end 21a of the first tie bar <NUM> on the first intersecting portion <NUM> side to the first intersecting portion <NUM> is not greater than <NUM>% of a length L1 (so-called periphery length along the sipe length direction) of the first sipe piece <NUM>.

The distance L2 represents the shortest distance from the end 21a to the first intersecting portion <NUM> in the tread planer view. In a case where a position of the end 21a of the first tie bar <NUM> changes in the height direction of the first tie bar <NUM>, the position of the end 21a is specified at the center position, in the height direction, of the first tie bar <NUM>. The first intersecting portion <NUM> is the vertex of the bent portion formed by connecting the first sipe piece <NUM> and the third sipe piece <NUM> to each other, and specified by the center line of the sipe in the tread planar view.

In conventional arrangement of the tie bar <NUM>, the closed sipe <NUM> is opened and closed according to the tread portion <NUM> being brought into contact with the ground and released, and the opening tends to be the largest near the first intersecting portion <NUM> at which the first sipe piece <NUM> and the third sipe piece <NUM> are continuous with each other, and heel-and-toe wear is likely to be generated particularly near the first intersecting portion <NUM>. Particularly, high load acts on a tire mounted to a light truck or a van, and this tendency is thus significant.

In the present invention, the first tie bar <NUM> is disposed near the first intersecting portion <NUM> at which the closed sipe <NUM> tends to be greatly opened, so that large opening near the first intersecting portion <NUM> and twisting of rubber are inhibited, and uneven wear such as heel-and-toe wear around the sipes can be reduced. The tire <NUM> of the present invention has such a mechanism and can thus exhibit excellent uneven wear resistance. The tire of the present invention can also be expected to have improved outer appearance by the above-described effect when the tire is worn.

The structure of the present embodiment will be described below in more detail. The structures described below represent specific modes of the present embodiment. Therefore, needless to say, also when the structures described below are not provided, the present invention can exhibit the above-described effects. Also when any one of the structures described below is applied alone to the tire of the present invention having the above-described features, improvement of performance corresponding to each structure can be expected. Furthermore, in a case where some of the structures described below are applied in combination, complex performance improvement corresponding to the structures can be expected.

The distance L2 is preferably not greater than <NUM>% of the length L1 of the first sipe piece <NUM> and more preferably not greater than <NUM>% of the length L1. In a more preferable mode, the end 21a of the first tie bar <NUM> may be substantially disposed at the first intersecting portion <NUM> (that is, the distance L2 is <NUM>). Thus, the above-described effect is more assuredly exhibited. As described below, the first tie bar <NUM> may be continuous with a tie bar disposed in the third sipe piece <NUM>, and the tie bar <NUM> may be disposed over the first sipe piece <NUM> and the third sipe piece <NUM>.

The first tie bar <NUM> extends substantially with a constant width in the tire radial direction. However, the present invention is not limited to such a structure. A width W1 (width along the first sipe piece <NUM>), in the sipe length direction, of the first tie bar <NUM> is preferably not less than <NUM>% of the length L1 of the first sipe piece <NUM> and more preferably not less than <NUM>% of the length L1, and preferably not greater than <NUM>% of the length L1 and more preferably not greater than <NUM>% of the length L1. Thus, uneven wear resistance can be enhanced while frictional force exhibited on ice by the closed sipes <NUM> is maintained. In a case where the width W1 changes in the height direction of the first tie bar <NUM>, the width W1 is measured at the center position, in the height direction, of the first tie bar <NUM>.

As shown in <FIG>, the maximum height h1 of the first tie bar <NUM> is <NUM>% to <NUM>% of the maximum depth d1 of the closed sipe <NUM>. The height h1 is preferably determined as appropriate according to the purpose of the tire. From such a viewpoint, in the case of winter tires for which on-snow performance is important, the height h1 is preferably <NUM>% to <NUM>% of the maximum depth d1 of the closed sipe <NUM>. Meanwhile, in the case of tires for all seasons which are considered to be used throughout the year, the height h1 is preferably <NUM>% to <NUM>% of the depth d1. Thus, performance according to the purpose of the tire is obtained.

As shown in <FIG>, in the present embodiment, the tie bar <NUM> includes a second tie bar <NUM> disposed in the second sipe piece <NUM>. From the viewpoint of enhancing uneven wear resistance, the second tie bar <NUM> has substantially the same structure as the first tie bar <NUM>. That is, as shown in <FIG>, the center 22c, in the sipe length direction, of the second tie bar <NUM> is disposed closer to the second intersecting portion <NUM> than the center 12c, in the length direction, of the second sipe piece <NUM> is. A distance L4 from an end 22a of the second tie bar <NUM> on the second intersecting portion <NUM> side to the second intersecting portion <NUM> is not greater than <NUM>% of a length L3 of the second sipe piece <NUM>. The above-described configuration of the first tie bar <NUM> can be applied to the second tie bar <NUM>, and the description thereof is omitted.

<FIG> is a cross-sectional view taken along a line A-A in <FIG>. As shown in <FIG>, the closed sipe <NUM> preferably includes a bent portion <NUM> that zigzags in the tire radial direction on the sipe transverse cross-section. The closed sipe <NUM> having such a structure can enhance stiffness of the land portion when the sipe walls opposing each other come into contact with each other, and uneven wear resistance can be further enhanced.

The bent portion <NUM> preferably includes two or more first protrusions <NUM> that protrude on one side. In the present embodiment, the bent portion <NUM> includes two first protrusions <NUM> and one second protrusion <NUM> that protrude on the other side between the two first protrusions <NUM>. A bent width W2 of the bent portion <NUM> is, for example, <NUM> to <NUM>. Thus, molding defect can be inhibited during vulcanization and molding while the above-described effect is exhibited.

In the present embodiment, the closed sipe <NUM> preferably includes a perpendicular portion <NUM> that extends parallel to the tire radial direction and is continuous with the inner side, in the tire radial direction, of the bent portion <NUM>. A length L5, in the tire radial direction, of the perpendicular portion <NUM> is, for example, <NUM>% to <NUM>% of the maximum depth d1 of the closed sipe <NUM>. The length L5, in the tire radial direction, of the perpendicular portion <NUM> is preferably less than the height h1 (shown in <FIG>) of the first tie bar <NUM>. Thus, a knife blade of the vulcanization mold for forming the bent portion <NUM> easily sticks in raw rubber of the tire during vulcanization and molding, and deformation of the knife blade or damage to the knife blade is inhibited.

As shown in <FIG>, in the present embodiment, the plurality of the closed sipes <NUM> are disposed along the tire axial direction. However, the plurality of the closed sipes <NUM> may be inclined relative to the tire axial direction to a certain degree. Specifically, an imaginary straight line <NUM> (indicated by alternate long and two short dashes line) connecting between the first end 8a of the closed sipe <NUM> disposed at the end of the first side B1 in the tire axial direction, and the second end 8b of the closed sipe <NUM> disposed at the end of the second side B2 in the tire axial direction is, for example, inclined relative to the tire axial direction at an angle of not greater than <NUM>°, preferably not greater than <NUM>°, and more preferably not greater than <NUM>°. However, arrangement of the closed sipes <NUM> is not limited to such arrangement, and can be changed according to the shape of the land portion.

In a more preferable mode, in the present embodiment, the first ends 8a of the closed sipes <NUM> included in one sipe group <NUM> are disposed on the same imaginary belt <NUM> (indicated by dots in <FIG>) extending parallel to the tire axial direction at a minute width. The width of the imaginary belt <NUM> is, for example, not greater than <NUM>. In a more preferable mode, the first ends 8a of the closed sipes <NUM> are disposed on the same imaginary straight line extending parallel to the tire axial direction. Similarly, the second ends 8b of the closed sipes <NUM> are disposed on the same imaginary belt (not shown) extending parallel to the tire axial direction at a minute width. The width of the imaginary belt is, for example, not greater than <NUM>. In a more preferable mode, the second ends 8b of the closed sipes <NUM> are disposed on the same imaginary straight line extending parallel to the tire axial direction.

<FIG> is an enlarged plan view of a plurality of the closed sipes <NUM>. As shown in <FIG>, an overlap length L7, in the tire axial direction, over which two closed sipes <NUM> adjacent to each other overlap each other is preferably <NUM>% to <NUM>% of the maximum length L6, in the tire axial direction, of the closed sipe <NUM>. The overlap length L7 is preferably <NUM> to <NUM> times the width W1 of the first tie bar <NUM>. Thus, excellent on-ice performance is exhibited while uneven wear resistance of the land portion <NUM> is maintained.

In the present embodiment, the first end 8a and the second end 8b are each disposed closer to the second side A2 in the tire circumferential direction than the first sipe piece <NUM> is, and disposed closer to the first side A1 in the tire circumferential direction than the second sipe piece <NUM> is. In other words, the first end 8a and the second end 8b are disposed in a region obtained by extending the third sipe piece <NUM> toward the both ends in the tire axial direction in parallel to the tire axial direction.

As shown in <FIG>, in the present embodiment, the closed sipe <NUM> includes a first outer sipe piece <NUM> and a second outer sipe piece <NUM>. The first outer sipe piece <NUM> extends from the first end 8a to the first sipe piece <NUM>. The second outer sipe piece <NUM> extends from the second end 8b to the second sipe piece <NUM>. The closed sipe <NUM> having such a structure allows high frictional force to be exhibited in the tire axial direction by the first outer sipe piece <NUM> and the second outer sipe piece <NUM>, and on-ice cornering performance is enhanced.

Each of an angle θ4 between the first sipe piece <NUM> and the third sipe piece <NUM>, and an angle θ5 between the second sipe piece <NUM> and the third sipe piece <NUM> is, for example, not less than <NUM>° and preferably not less than <NUM>°. In the present embodiment, the angle θ4 and the angle θ5 are each <NUM> to <NUM>°. Thus, wear at a portion at which the closed sipe <NUM> is bent is reduced, and uneven wear resistance is enhanced.

From a similar viewpoint, each of an angle θ6 between the first sipe piece <NUM> and the first outer sipe piece <NUM>, and an angle θ7 between the second sipe piece <NUM> and the second outer sipe piece is, for example, not less than <NUM>° and preferably not less than <NUM>°. In the present embodiment, the above-described two angles are each <NUM> to <NUM>°.

The length L1 of the first sipe piece <NUM> and the length L3 of the second sipe piece <NUM> are each greater than the length of the third sipe piece <NUM>. The length L1 of the first sipe piece <NUM> and the length L3 of the second sipe piece <NUM> are each <NUM>% to <NUM>% of the largest length L6 (shown in <FIG>), in the tire axial direction, of the closed sipe <NUM>.

As shown in <FIG>, the length L8, in the tire circumferential direction, of the third sipe piece <NUM> is, for example, <NUM> to <NUM> times the width W1 of the first tie bar <NUM>. The third sipe piece <NUM> having such a structure contributes to well-balanced enhancement of uneven wear resistance and on-ice performance.

As shown in <FIG>, in the present embodiment, the closed sipes <NUM> are disposed such that the third sipe pieces <NUM> are parallel to each other. Thus, uneven wear resistance is further enhanced.

As shown in <FIG>, the first outer sipe piece <NUM> and the second outer sipe piece <NUM> each have a length less than the third sipe piece <NUM>. The length of the first outer sipe piece <NUM> is preferably <NUM>% to <NUM>% of the length of the third sipe piece <NUM>. The same applies to the second outer sipe piece <NUM>. The first outer sipe piece <NUM> and the second outer sipe piece <NUM> having such structures contribute to well-balanced enhancement of uneven wear resistance and on-ice performance.

As shown in <FIG>, in the present embodiment, in the two closed sipes <NUM> adjacent to each other in the tire axial direction, the second sipe piece <NUM> of the closed sipe <NUM> on one side overlaps the first sipe piece <NUM> of the closed sipe <NUM> on the other side in the tire axial direction. The second outer sipe piece <NUM> of the closed sipe <NUM> on the one side extends from the second sipe piece <NUM> toward the first side A1 in the tire circumferential direction. The first outer sipe piece <NUM> of the closed sipe <NUM> on the other side extends from the first sipe piece <NUM> toward the second side A2 in the tire circumferential direction. Thus, the above-described effect is more assuredly exhibited.

<FIG> is a transparent perspective view of an example of the inside of the closed sipe <NUM> according to another embodiment of the present invention. In the other embodiment described below, the components common to those of the above-described embodiment are denoted by the same reference numerals, and the above-described structures can be applied to the components.

As shown in <FIG>, the tie bar <NUM> of the present embodiment includes at least one third tie bar <NUM> disposed in the third sipe piece <NUM>. The end of the first tie bar <NUM> on the first intersecting portion <NUM> side is disposed at the first intersecting portion <NUM>. The third tie bar <NUM> includes a first reinforcing tie bar 23a continuous with the first tie bar <NUM>. Thus, the closed sipe <NUM> of the present embodiment includes a tie bar disposed over the first sipe piece <NUM> and the third sipe piece <NUM>. The tie bar having such a structure can effectively inhibit the first sipe piece <NUM> and the third sipe piece <NUM> from being opened, and uneven wear can be reduced.

In a more preferable mode, the closed sipe <NUM> of the present embodiment includes the second tie bar <NUM>, and the end of the second tie bar <NUM> on the second intersecting portion <NUM> side is disposed at the second intersecting portion <NUM>. The third tie bar <NUM> includes a second reinforcing tie bar 23b continuous with the second tie bar <NUM>. Thus, the closed sipe <NUM> of the present embodiment includes a tie bar disposed over the second sipe piece <NUM> and the third sipe piece <NUM>. Such arrangement of the tie bar allows enhancement of uneven wear resistance.

The tire <NUM> of the present invention can be obtained by a known manufacturing method by using a vulcanization mold having a sipe blade corresponding to the shape of the above-described sipe.

The tire according to the embodiments of the present invention has been described above in detail. However, the present invention is not limited to the above-described specific embodiments, and various modification can be made to implement the present invention as long as it falls within the scope of protection as defined in the claims.

Pneumatic tires each having the plurality of closed sipes described above and having a size of <NUM>/65R15 were produced as test tires according to the specifications indicated in Table <NUM>. As a test tire for comparative example <NUM>, a tire in which the closed sipes did not include tie bars was produced. As test tires for comparative examples <NUM> and <NUM>, tires in each of which a distance from the end of the first tie bar to the first intersecting portion was greater than <NUM>% of the length of the first sipe piece were produced. The test tires had substantially the same structure except for the above-described matters. Each test tire was tested for uneven wear resistance. The specifications common to the test tires and a test method were as follows.

The above-described test vehicle was caused to run on an ordinary road over a certain distance. Thereafter, a state where uneven wear such as heel-and-toe wear was generated around the closed sipe was visually confirmed and evaluated. The results are indicated as scores with the uneven wear generating state of comparative example <NUM> being <NUM>. The greater the value is, the less uneven wear is and the more excellent uneven wear resistance is.

Claim 1:
A tire (<NUM>) comprising
a tread portion (<NUM>), wherein
the tread portion (<NUM>) includes a land portion (<NUM>),
a plurality of closed sipes (<NUM>) each having a width of not greater than <NUM> are aligned in a tire axial direction in the land portion (<NUM>),
each of the closed sipes (<NUM>) includes
a sipe bottom (8d),
a first end (8a) and a second end (8b) in the tire axial direction,
a first sipe piece (<NUM>) extending on the first end (8a) side at a first angle (θ1) relative to the tire axial direction,
a second sipe piece (<NUM>) extending on the second end (8b) side at a second angle (θ2) relative to the tire axial direction,
a third sipe piece (<NUM>) continuous with the first sipe piece (<NUM>) and the second sipe piece (<NUM>) at a first intersecting portion (<NUM>) and a second intersecting portion (<NUM>), respectively, the third sipe piece (<NUM>) extending at a third angle (θ3) different from the first angle (θ1) and the second angle (θ2) relative to the tire axial direction, and
at least one tie bar (<NUM>) formed by the sipe bottom (8d) locally protruding outward in a tire radial direction,
the closed sipes (<NUM>) aligned in the tire axial direction overlap each other in the tire axial direction and a tire circumferential direction,
the tie bar (<NUM>) includes a first tie bar (<NUM>) disposed in the first sipe piece (<NUM>),
a center (21c), in a sipe length direction, of the first tie bar (<NUM>) is disposed closer to the first intersecting portion (<NUM>) than a center (11c), in a length direction, of the first sipe piece (<NUM>) is, and
a distance (L2) from an end (21a) of the first tie bar (<NUM>) on the first intersecting portion (<NUM>) side to the first intersecting portion (<NUM>) is not greater than <NUM>% of a length (L1) of the first sipe piece (<NUM>),
wherein each closed sipe (<NUM>) includes a bent portion (<NUM>) that zigzags in the tire radial direction, on a transverse cross-section of the sipe (<NUM>).