JP7638175B2 - Pneumatic tires - Google Patents

Description

This disclosure relates to pneumatic tires.

Patent Document 1 discloses a pneumatic tire that includes circumferential sipes formed by a first blade and extending along the tire circumferential direction, axial sipes formed by a second blade and extending along the tire axially outward, and a connection portion formed by a raised portion and connecting one end of the axial sipe to the circumferential sipe. The provision of the connection portion prevents rubber burrs from being formed between the circumferential sipe and the axial sipe.

However, if a connection is provided between a circumferential sipe and an axial sipe extending from the circumferential sipe along the axially inward direction of the tire, water flowing through the circumferential sipe may flow back from the connection to the axially inward direction of the tire, which may deteriorate the drainage performance of the pneumatic tire.

JP 2019-18450 A

The objective of this disclosure is to provide a pneumatic tire that prevents water from flowing back from the connection, thereby preventing deterioration of drainage.

The pneumatic tire disclosed herein includes a main groove extending in the tire circumferential direction, a circumferential sipe disposed axially outboard of the main groove and extending along the tire circumferential direction, an axial sipe disposed between the main groove and the circumferential sipe and extending along the tire axial direction, and a connection portion connecting one end of the axial sipe to the circumferential sipe, the other end of the axial sipe being directly or indirectly connected to the main groove, and the connection portion being narrowed toward the axially outboard side of the tire.

FIG. 1 is a cross-sectional view of a pneumatic tire according to an embodiment of the present invention taken along a tire meridian plane. FIG. 2 is a diagram showing a tread pattern of a pneumatic tire according to the embodiment; An enlarged view of region III in FIG. Enlarged cross-sectional view of line IV-IV in FIG. An enlarged cross-sectional view of line VV in FIG. FIG. 13 is an enlarged view showing a main portion of a tread pattern of a pneumatic tire according to another embodiment.

One embodiment of a pneumatic tire will be described below with reference to Figures 1 to 5. Note that in each figure (including Figure 6), the dimensional ratios in the drawing do not necessarily match the actual dimensional ratios, and the dimensional ratios between the drawings do not necessarily match either.

In each figure, the first direction D1 is the tire axial direction D1 that is parallel to the tire rotation axis of the pneumatic tire (hereinafter also simply referred to as "tire") 1, the second direction D2 is the tire radial direction D2 that is the diameter direction of the tire 1, and the third direction D3 is the tire circumferential direction D3 around the tire rotation axis.

In the tire axial direction D1, the inside is the side closer to the tire equatorial plane S1, and the outside is the side farther from the tire equatorial plane S1. In the tire radial direction D2, the inside is the side closer to the tire rotation axis, and the outside is the side farther from the tire rotation axis.

The tire equatorial plane S1 is a plane perpendicular to the tire rotation axis and located at the center of the tire axial direction D1 of the tire 1, and the tire meridian plane is a plane that includes the tire rotation axis and is perpendicular to the tire equatorial plane S1. The tire equatorial line L1 is a line where the outer surface of the tire 1 in the tire radial direction D2 (the tread surface 2a described later) and the tire equatorial plane S1 intersect.

As shown in FIG. 1, the tire 1 according to this embodiment includes a pair of beads 11, sidewalls 12 extending outward from each bead 11 in the tire radial direction D2, a tread 13 continuing to the outer ends of the pair of sidewalls 12 in the tire radial direction D2, and a carcass ply 14 extending between the pair of beads 11.

The tread 13 comprises a tread rubber 2 having a tread surface 2a that constitutes the outer surface of the tread 13, and a belt layer 15 and a belt reinforcing layer 16 that are disposed between the tread rubber 2 and the carcass ply 14. The tread surface 2a has a tire contact surface that actually contacts the road surface, and the outer ends of the tire contact surface in the tire axial direction D1 are called tread contact ends 2b, 2b.

The tire contact surface is the part that comes into contact with the road surface when tire 1 is mounted on a standard rim (not shown), inflated to the standard internal pressure, placed vertically on a flat road surface, and a standard load is applied.

A genuine rim is a rim that is determined for each tire by the standard system that includes the standard on which the tire is based. For example, in the case of JATMA, it is called a standard rim, in the case of TRA, it is called a "Design Rim," and in the case of ETRTO, it is called a "Measuring Rim."

The normal internal pressure is the air pressure set for each tire by each standard in the standard system on which the tire is based. For JATMA, it is the maximum air pressure, for TRA, it is the maximum value listed in the table "TIRE LOAD LIMITS AT VARIOUS COLD INFLATION PRESSURES", and for ETRTO, it is the "INFLATION PRESSURE".

The normal load is the load that each standard specifies for each tire in the standard system on which the tire is based. For JATMA, it is the maximum load capacity, for TRA, it is the maximum value listed in the table above, and for ETRTO, it is the "LOAD CAPACITY."

As shown in Figures 1 and 2, the tire 1 has a main groove 3 formed on the tread surface 2a and extending in the tire circumferential direction D3. In this embodiment, the main groove 3 is a groove having a groove width greater than 1.5 mm.

The main groove 3 includes a pair of shoulder main grooves 32, 32 located on the outermost side in the tire axial direction D1, and a center main groove 31 located between the pair of shoulder main grooves 32, 32. The center main groove 31 extends in a zigzag shape with repeated bends and is located on the tire equator line L1. The center main groove 31 has multiple projections and recesses formed by the main groove wall of the center main groove 31, which are alternately repeated along the tire circumferential direction D3. The shoulder main groove 32 extends in a straight line and is spaced apart from the center main groove 31 in the tire axial direction D1. The shapes and numbers of the center main groove 31 and shoulder main grooves 32 are not limited to those described above.

The tire 1 has multiple lands defined by multiple main grooves 3. In this embodiment, the tire 1 has a pair of center lands 4, 4 formed between the center main groove 31 and the shoulder main groove 32, and a pair of shoulder lands 5, 5 formed outside the shoulder main groove 32 in the tire axial direction D1.

As shown in FIG. 2, the tire 1 includes a plurality of recesses 6 extending from the main groove 3 along the tire axial direction D1, a plurality of axial grooves 17 extending along the tire axial direction D1 and positioned outward of the shoulder main groove 32 in the tire axial direction D1, and a circumferential groove 18 extending along the tire circumferential direction D3 and positioned outward of the shoulder main groove 32 in the tire axial direction D1. In this embodiment, the recesses 6 are grooves having a groove width greater than 1.5 mm, and the grooves 17 and 18 are grooves having a groove width narrower than the groove width of the main groove 3.

The recess 6 includes a center recess 61 located on the center land 4 and a shoulder recess 62 located on the shoulder land 5. The center recess 61 includes a first center recess 611 extending from the center main groove 31 toward the outside in the tire axial direction D1, and a second center recess 612 extending from the shoulder main groove 32 toward the inside in the tire axial direction D1.

The first center recess 611 extends from a corner on the protruding side (close to the shoulder main groove 32) of the zigzag center main groove 31. The first center recess 611 is arranged on both outer sides of the center main groove 31 in the tire axial direction D1 so as to form a pair across the tire equator line L1. The pair of first center recesses 611, 611 is arranged at the corners of the center main groove 31 that are adjacent to each other in the tire circumferential direction D3. The first center recess 611 has one end that terminates within the center land 4 and the other end that is connected to the center main groove 31.

The second center recess 612 extends from the shoulder main groove 32 toward the inside in the tire axial direction D1. The second center recess 612 is arranged on the inside of the pair of shoulder main grooves 32, 32 in the tire axial direction D1 so as to form a pair on either side of the tire equator line L1. The second center recess 612 is arranged alternately between the first center recess 611 with respect to the tire circumferential direction D3 position. The second center recess 612 has one end connected to the shoulder main groove 32 and the other end terminating within the center land 4.

The shoulder recess 62 extends from the shoulder main groove 32 toward the outside in the tire axial direction D1. In this embodiment, the shoulder recess 62 is arranged on the outside of the pair of shoulder main grooves 32, 32 in the tire axial direction D1 so as to form a pair on either side of the tire equator line L1, but is not limited to this. For example, the shoulder recess 62 may be arranged only on the outside of one of the shoulder main grooves 32 in the tire axial direction D1.

The shoulder recesses 62 are arranged alternately between the second center recesses 612 in the tire circumferential direction D3. The shoulder recesses 62 are arranged at substantially the same positions as the first center recesses 611 in the tire circumferential direction D3. The shoulder recesses 62 have one end that terminates within the shoulder land 5 and the other end that is connected to the shoulder main groove 32. The length of the shoulder recesses 62 in the tire axial direction D1 is shorter than the length of the first center recesses 611 and the second center recesses 612 in the tire axial direction D1.

In this embodiment, the first center recess 611, the second center recess 612, and the shoulder recess 62 are notch grooves, but are not limited to this. For example, each recess 611, 612, 62 may be a lateral groove, etc. Each recess 611, 612, 62 extends at an angle in the same direction with respect to the tire axial direction D1, but are not limited to this. For example, each recess 611, 612, 62 may extend parallel to the tire axial direction D1.

The axial grooves 17 are arranged alternately between the shoulder recesses 62 in the tire circumferential direction D3. The axial grooves 17 are arranged at both outer ends of the tread surface 2a in the tire axial direction D1 so as to form pairs across the tire equator line L1. The axial grooves 17 have one end connected to the circumferential slit 18 and the other end terminating within the shoulder land 5.

In this embodiment, the inner portion 17a of the axial groove 17 is inclined with respect to the tire axial direction D1, but is not limited to this. For example, the inner portion 17a may be parallel to the tire axial direction D1. The inclination direction of the inner portion 17a with respect to the tire axial direction D1 is opposite to the inclination direction of the first center recess 611, the second center recess 612, and the shoulder recess 62 with respect to the tire axial direction D1.

The tire 1 has a circumferential sipe 7 that is disposed outside the main groove 3 in the tire axial direction D1 and extends along the tire circumferential direction D3, and a number of axial sipes 8 that extend along the tire axial direction D1. In this embodiment, the sipes 7 and 8 are elongated cuts with a sipe width of 1.5 mm or less.

In this embodiment, the circumferential sipes 7 are disposed further outward in the tire axial direction D1 than the shoulder main grooves 32. That is, the circumferential sipes 7 are disposed on the shoulder land 5. Note that the circumferential sipes 7 may be disposed, for example, between the center main groove 31 and the shoulder main groove 32 (on the center land 4).

In this embodiment, the circumferential sipes 7 are arranged on a pair of shoulder lands 5, 5 to form a pair on either side of the tire equator line L1, but this is not limited to this. For example, the circumferential sipes 7 may be arranged only on one of the shoulder lands 5. In this embodiment, the circumferential sipes 7 extend parallel to the tire circumferential direction D3, but this is not limited to this. For example, the circumferential sipes 7 may extend at an angle to the tire circumferential direction D3. The circumferential sipes 7 may extend continuously or discontinuously along the tire circumferential direction D3.

2 and 3, the axial sipes 8 include a first axial sipe 81 disposed between the main groove 3 and the circumferential sipe 7, a second axial sipe 82 disposed outside the circumferential sipe 7 in the tire axial direction D1, and closed sipes 83 disposed within the center land 4 and the shoulder land 5. From the viewpoint of improving drainage, the shapes of the first axial sipe 81 and the second axial sipe 82 are preferably linear. Note that the shapes of the first axial sipe 81 and the second axial sipe 82 may be, for example, wavy.

In this embodiment, the first axial sipes 81 are disposed between the shoulder main groove 32 and the circumferential sipe 7. That is, the first axial sipes 81 are disposed on the shoulder land 5. In this embodiment, the first axial sipes 81 are disposed on each of a pair of shoulder lands 5, 5 so as to be paired on either side of the tire equator line L1, but this is not limited to this. For example, the first axial sipes 81 may be disposed only on one of the shoulder lands 5.

One end of the first axial sipe 81 (the outer end in the tire axial direction D1) is connected to the circumferential sipe 7 via a first connection portion 9 described below. The other end of the first axial sipe 81 (the inner end in the tire axial direction D1) is directly or indirectly connected to the main groove 3.

In this embodiment, the other end of the first axial sipe 81 is indirectly connected to the shoulder main groove 32 via the shoulder recess 62, but is not limited to this. For example, the other end of the shoulder main groove 32 may be directly connected to the shoulder main groove 32 without going through the shoulder recess 62.

As shown in FIG. 3, the groove width Wsd of the shoulder recess 62 is greater than the sipe width Ws1 of the first axial sipe 81. As shown in FIG. 4, the groove depth Hsd of the shoulder recess 62 is greater than the sipe depth Hs1 of the first axial sipe 81.

2 and 3, in this embodiment, the second axial sipes 82 are arranged on the shoulder land 5. In this embodiment, the second axial sipes 82 are arranged on each of a pair of shoulder lands 5, 5 so as to sandwich the tire equator line L1, but this is not limited to this. For example, the second axial sipes 82 may be arranged only on one of the shoulder lands 5.

One end of the second axial sipe 82 (outer end in the tire axial direction D1) is connected to the axial groove 17. The other end of the second axial sipe 82 (inner end in the tire axial direction D1) is connected to the circumferential sipe 7 via a second connection portion 10 described below. The inclination direction of the second axial sipe 82 with respect to the tire axial direction D1 is opposite to the inclination direction of the first axial sipe 81 with respect to the tire axial direction D1.

The tire 1 includes a first connection portion 9 that connects one end of the first axial sipe 81 to the circumferential sipe 7, and a second connection portion 10 that connects the other end of the second axial sipe 82 to the circumferential sipe 7. This configuration can prevent rubber burrs from being formed between the circumferential sipe 7 and the first axial sipe 81 (second axial sipe 82), and ensures the drainage of the tire 1. If there was no raised portion that forms the first connection portion 9 (second connection portion 10) in the mold, it would be difficult to butt the blade that forms the circumferential sipe 7 and the blade that forms the axial sipe 8 together without any gaps, and rubber burrs would be generated in the gap between the blades. In this embodiment, the width of at least a portion of the connection portions 9 and 10 is greater than the sipe width of the sipes 7 and 8.

The first connection portion 9 is narrowed toward the outside in the tire axial direction D1. That is, as shown in FIG. 3, the first width W1 at the inner end of the first connection portion 9 in the tire axial direction D1 is larger than the second width W2 at the outer end of the first connection portion 9 in the tire axial direction D1. The second width W2 is preferably 50% to 80% of the first width W1. The first width W1 is the widthwise dimension of the first axial sipe 81, and the second width W2 is the lengthwise dimension of the circumferential sipe 7.

From the viewpoint of allowing for misalignment due to manufacturing errors between the raised portion forming the first connection portion 9 in the mold and the blade forming the first axial sipe 81, it is preferable that the first width W1 is larger than the sipe width Ws1 of the first axial sipe 81.

The second width W2 is preferably 90-110% of the sipe width Ws1, and more preferably is substantially the same as the sipe width Ws1. If the second width W2 is too small compared to the sipe width Ws1, the raised portion forming the first connection portion 9 may be damaged, and if the second width W2 is too large compared to the sipe width Ws1, water flowing through the circumferential sipe 7 is more likely to enter the first connection portion 9, and water is more likely to flow back from the circumferential sipe 7 to the first connection portion 9 (first axial sipe 81).

In this embodiment, the first connection portion 9 has a substantially symmetrical shape with respect to the imaginary line L2 passing through the center of the first axial sipe 81 in the width direction, but is not limited to this. For example, the first connection portion 9 may have an asymmetrical shape with respect to the imaginary line L2 (e.g., an offset shape with respect to the imaginary line L2). The first connection portion 9 is inclined with respect to the tire axial direction D1, and the inclination angle of the first connection portion 9 with respect to the tire axial direction D1 is substantially the same as the inclination angle of the first axial sipe 81 with respect to the tire axial direction D1.

The first side wall surface 9a of the first connection portion 9 along the tire axial direction D1 extends linearly when viewed in the tire radial direction D2, but is not limited to this. For example, the first side wall surface 9a may extend in an arc shape.

As shown in FIG. 4, in this embodiment, the first bottom surface 9b of the first connection portion 9 is inclined inward in the tire radial direction D2 toward the outside in the tire axial direction D1. That is, the first depth H1 of the first connection portion 9 at the inner end in the tire axial direction D1 is smaller than the second depth H2 of the first connection portion 9 at the outer end in the tire axial direction D1. It is preferable that the second depth H2 is 130% to 180% of the first depth H1. Note that the first bottom surface 9b may be parallel to the tread surface 2a, for example. That is, the first depth H1 may be the same as the second depth H2.

From the viewpoint of ensuring the durability of the raised portion that forms the first connection portion 9 in the mold, it is preferable that the first depth H1 and the second depth H2 are smaller than the sipe depth Hs1 of the first axial sipe 81 and the sipe depth Hs2 of the circumferential sipe 7. In this embodiment, the first bottom surface 9b is inclined linearly, but is not limited to this. For example, the first bottom surface 9b may be inclined in an arc.

2 and 3, when the shoulder land 5 touches the ground, the first connection part 9 is crushed and deformed, and when the shoulder land 5 leaves the road surface, the shape of the first connection part 9 returns to its original shape. As a result, the shape of the first connection part 9 returns to its original shape, that is, the groove capacity of the first connection part 9 changes (increases), so that the first connection part 9 acts as a pump and easily draws water from the first axial sipe 81, improving the drainage of the tire 1. In addition, by crushing the first connection part 9 when it touches the ground, the second width W2 becomes smaller, and it is possible to suppress water from flowing back from the circumferential sipe 7 to the first axial sipe 81.

In this embodiment, the second connection portion 10 has an asymmetric shape with respect to the imaginary line L3 passing through the center of the second axial sipe 82 in the width direction, but is not limited to this. For example, the second connection portion 10 may have a substantially symmetric shape with respect to the imaginary line L3.

The second connection portion 10 is inclined with respect to the tire axial direction D1, and the inclination angle of the second connection portion 10 with respect to the tire axial direction D1 is substantially the same as the inclination angle of the second axial sipe 82 with respect to the tire axial direction D1. The inclination direction of the second connection portion 10 with respect to the tire axial direction D1 is opposite to the inclination direction of the first connection portion 9 with respect to the tire axial direction D1.

The second side wall surface 10a of the second connection portion 10 along the tire axial direction D1 extends linearly when viewed in the tire radial direction D2, but is not limited to this. For example, the second side wall surface 10a may extend in an arc shape.

The second connection portion 10 is narrowed toward the outside in the tire axial direction D1. That is, the third width W3 at the inner end of the second connection portion 10 in the tire axial direction D1 is larger than the fourth width W4 at the outer end of the second connection portion 10 in the tire axial direction D1. The fourth width W4 is preferably 50% to 80% of the third width W3. The third width W3 is the lengthwise dimension of the circumferential sipe 7, and the fourth width W4 is the widthwise dimension of the second axial sipe 82.

The third width W3 is larger than the sipe width Ws2 of the second axial sipe 82. This allows water to easily drain from the circumferential sipe 7 to the second axial sipe 82, improving the drainage of the tire 1. From the viewpoint of allowing for misalignment due to manufacturing errors between the raised portion forming the second connection portion 10 in the mold and the blade forming the second axial sipe 82, it is preferable that the fourth width W4 is larger than the sipe width Ws2.

As shown in FIG. 5, in this embodiment, the second bottom surface 10b of the second connection portion 10 is inclined inward in the tire radial direction D2 toward the outside in the tire axial direction D1. That is, the third depth H3 at the inner end of the second connection portion 10 in the tire axial direction D1 is smaller than the fourth depth H4 at the outer end of the second connection portion 10 in the tire axial direction D1. With this configuration, the groove capacity of the second connection portion 10 can be increased toward the outside in the tire axial direction D1. This makes it easier for water to drain from the circumferential sipe 7 to the second axial sipe 82, for example, improving the drainage of the tire 1.

From the viewpoint of ensuring the durability of the raised portion for forming the second connection portion 10, the third depth H3 and the fourth depth H4 are preferably smaller than the sipe depth Hs2 of the circumferential sipe 7 and the depth Hs3 of the second axial sipe 82. The fourth depth H4 is preferably 130% to 180% of the third depth H3. In this embodiment, the second bottom surface 10b is inclined linearly, but is not limited to this. For example, the second bottom surface 10b may be inclined in an arcuate shape or may be parallel to the tread surface 2a.

As described above, in this embodiment, the tire 1 includes a main groove 3 (shoulder main groove 32) extending in the tire circumferential direction D3, a circumferential sipe 7 disposed outside the main groove 3 (shoulder main groove 32) in the tire axial direction D1 and extending along the tire circumferential direction D3, a first axial sipe 81 disposed between the main groove 3 (shoulder main groove 32) and the circumferential sipe 7 and extending along the tire axial direction D1, and a first connection portion 9 connecting one end of the first axial sipe 81 to the circumferential sipe 7, and the other end of the first axial sipe 81 is directly or indirectly connected to the main groove 3 (shoulder main groove 32), and the first connection portion 9 is preferably formed narrower toward the outside in the tire axial direction D1.

With this configuration, the first connection portion 9 is narrowed toward the circumferential sipe 7, so water flowing through the circumferential sipe 7 is less likely to enter the first connection portion 9. This makes it possible to prevent water from flowing back from the first connection portion 9, and thus to prevent deterioration of the drainage properties of the tire 1.

Furthermore, as in the tire 1 according to this embodiment, it is preferable that the first connection portion 9 has a shape that is approximately symmetrical with respect to the imaginary line L2 that passes through the center of the first axial sipe 81 in the width direction.

With this configuration, when water flows into the first connection part 9, the water flows along the pair of first side wall surfaces 9a, 9a of the first connection part 9 can be made equal. This reduces the flow resistance caused by the difference in the water flows, and improves the drainage performance of the tire 1.

Furthermore, as in the tire 1 according to this embodiment, it is preferable that the first bottom surface 9b of the first connection portion 9 is inclined inward in the tire radial direction D2 toward the outside in the tire axial direction D1.

With this configuration, by deepening the first bottom surface 9b toward the narrow side of the first connection portion 9, the groove capacity of the first connection portion 9 can be secured, and water can easily drain from the first axial sipe 81 to the circumferential sipe 7. This improves the drainage of the tire 1.

Furthermore, as in this embodiment, the tire 1 has a recess 6 (shoulder recess 62) disposed between the main groove 3 (shoulder main groove 32) and the circumferential sipe 7 and extending along the tire axial direction D1, the recess 6 (shoulder recess 62) has one end terminating within the land (shoulder land 5) and the other end connected to the main groove 3 (shoulder main groove 32), the other end of the first axial sipe 81 is connected to one end of the recess 6 (shoulder recess 62), and the groove width Wsd of the recess 6 (shoulder recess 62) is greater than the sipe width Ws1 of the first axial sipe 81.

With this configuration, the first axial sipe 81 is connected to the shoulder main groove 32 via the shoulder recess 62, which has a groove width larger than the sipe width Ws1 of the first axial sipe 81, so that water flowing through the shoulder main groove 32 can easily flow to the first axial sipe 81. This improves the drainage of the tire 1.

The tire 1 is not limited to the configuration of the embodiment described above, and is not limited to the above-mentioned effects. Furthermore, the tire 1 can of course be modified in various ways without departing from the spirit of the present invention. For example, it is of course possible to arbitrarily select one or more of the configurations, methods, etc. related to the various modified examples described below and adopt them in the configurations, methods, etc. related to the embodiment described above.

(1) In the tire 1 according to this embodiment, the circumferential sipes 7, the first axial sipes 81, and the first connecting portion 9 are arranged on the outer side of the shoulder main groove 32 in the tire axial direction D1 (on the shoulder land 5). However, the tire 1 is not limited to such a configuration. For example, in the tire 1, the circumferential sipes 7, the first axial sipes 81, and the first connecting portion 9 may be arranged between the center main groove 31 and the shoulder main groove 32 (on the center land 4). The same applies to the second axial sipes 82 and the second connecting portion 10. In such a configuration, the first axial sipes 81 may be connected to the first center recess 611.

(2) As shown in FIG. 6, one end 81a of the first axial sipe 81 may be positioned further outward in the tire axial direction D1 than the other end 9c of the first connection portion 9. With this configuration, it is possible to prevent a gap from being generated between the blade that forms the first axial sipe 81 and the raised portion that forms the first connection portion 9 in the mold, and to prevent rubber burrs from being generated between the first axial sipe 81 and the first connection portion 9. The same applies to the second axial sipe 82 and the second connection portion 10.

1... tire, 2... tread rubber, 2a... tread surface, 2b... tread ground edge, 3... main groove, 31... center main groove, 32... shoulder main groove, 4... center land, 5... shoulder land, 6... recess, 61... center recess, 611... first center recess, 612... second center recess, 62... shoulder recess, 7... circumferential sipe, 8... axial sipe, 81... first axial sipe, 82... second axial sipe, 83... closed sipe, 9... first connection portion, 9a... first side wall surface, 9b... first bottom surface, 10... second connection portion, 10a... second side wall surface, 10b... second bottom surface, 11... bead, 12... sidewall, 13... tread, 14... carcass ply, 15... belt layer, 16... belt reinforcing layer, 17... axial groove, 17a... inner portion, 18... circumferential groove

Claims (4)

A main groove extending in a tire circumferential direction;
A circumferential sipe is disposed axially outward of the main groove and extends along the circumferential direction of the tire.
an axial sipe disposed between the main groove and the circumferential sipe and extending along the tire axial direction;
a connection portion connecting one end of the axial sipe and the circumferential sipe,
The other end of the axial sipe is directly or indirectly connected to the main groove,
The connection portion is formed so as to narrow toward an outer side in the tire axial direction. The pneumatic tire according to claim 1, wherein the connection portion is substantially symmetrical with respect to an imaginary line passing through the center of the axial sipe in the width direction. The pneumatic tire according to claim 1 or 2, wherein the bottom surface of the connection portion is inclined radially inward toward the axially outward side of the tire. A recess is disposed between the main groove and the circumferential sipe and extends along the tire axial direction,
The recess has one end terminating within land and the other end connected to the main groove,
The other end of the axial sipe is connected to one end of the recess,
The pneumatic tire according to any one of claims 1 to 3, wherein a width of the recess is greater than a width of the axial sipe.