JP2023075537A - pneumatic tire - Google Patents

Abstract

To provide a pneumatic tire capable of suppressing in-plane contraction in a tire circumferential direction while ensuring snow column shearing force.SOLUTION: A pneumatic tire is equipped with a shoulder main groove that is disposed on the outermost side in a tire width direction of a plurality of main grooves formed on a tread so as to extend in a tire circumferential direction, and a shoulder lateral groove that extends outward in a tire width direction from the shoulder main groove. The shoulder main groove is equipped with a bottom-up portion raising a groove bottom at an intersecting portion with the shoulder lateral groove. The height of the bottom-up portion is 30% or less of the groove depth of the shoulder main groove.SELECTED DRAWING: Figure 3

Description

The present disclosure relates to pneumatic tires.

Patent Literature 1 listed below discloses a pneumatic tire capable of reducing rolling resistance and reducing noise while maintaining snow traction performance. This pneumatic tire includes shoulder main grooves extending in the tire circumferential direction and a plurality of shoulder lug grooves connected to the shoulder main grooves from outside in the tire width direction. A raised bottom is formed.

By the way, in a pneumatic tire, when the tread rubber contacts the road surface, the curved surface deforms into a flat surface. As a result, the tread rubber is deformed along the tire circumferential direction (in-plane shrinkage) because the in-plane contractive force acting from both sides in the tire circumferential direction toward the center side acts on the ground contact surface that is in contact with the road surface. . In-plane shrinkage tends to lead to deterioration of road-hugging properties, and accordingly steering stability and wear performance tend to deteriorate.

The pneumatic tire of Patent Document 1 has a configuration in which no raised portion is provided at the intersection of the shoulder main groove and the shoulder lug groove in order to secure the shear force of the snow column. Not effective in suppressing contraction.

JP 2018-34698 A

An object of the present disclosure is to provide a pneumatic tire capable of suppressing in-plane shrinkage in the tire circumferential direction while ensuring a snow column shear force.

A pneumatic tire of the present disclosure includes a shoulder main groove arranged on the outermost side in the tire width direction among a plurality of main grooves formed in the tread so as to extend along the tire circumferential direction;
a shoulder lateral groove extending outward in the tire width direction from the shoulder main groove,
The shoulder main groove has a raised bottom portion at the intersection with the shoulder lateral groove, and the height of the raised bottom portion is 30% or less of the groove depth of the shoulder main groove.

FIG. 2 is a cross-sectional view of the essential parts of the pneumatic tire according to the present embodiment in the tire meridional plane. A plan view of a pneumatic tire according to the present embodiment Enlarged view of area III in Fig. 2 Enlarged cross-sectional view of essential parts taken along IV-IV line in Fig. 3 Enlarged cross-sectional view of essential parts taken along line VV in FIG. Partially enlarged view of a pneumatic tire according to another embodiment

An embodiment of a pneumatic tire will be described below with reference to FIGS. 1 to 5. FIG. In each drawing, the dimensional ratio of the drawing and the actual dimensional ratio do not necessarily match, and the dimensional ratio between the drawings does not necessarily match.

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

In the tire width direction D1, the inner side is the side closer to the tire equatorial plane S1, and the outer side is the side farther from the tire equatorial plane S1. In the tire width direction D1, the first side D11 is also called the first width direction side D11, and the second side D12 is also called the second width direction side D12. In addition, in the tire radial direction D2, the inner side is the side closer to the tire rotation axis, and the outer side is the side farther from the tire rotation axis.

The tire equatorial plane S1 is a plane orthogonal to the tire rotation axis and is located at the center of the tire width direction D1 of the tire 1, and the tire meridional plane is a plane including the tire rotation axis and the tire equator. It is a plane perpendicular to the plane S1. Further, the tire equator line is a line where an outer surface (a tread surface 2a described later) of the tire 1 in the tire radial direction D2 intersects with the tire equatorial plane S1.

As shown in FIG. 1, the tire 1 according to the present embodiment includes a pair of beads 1a having a bead core, sidewalls 1b extending outward in the tire radial direction D2 from each bead 1a, and a tire diameter of the pair of sidewalls 1b. A tread 2 is connected to the outer end in the direction D2, and the outer surface in the tire radial direction D2 contacts the road surface. In this embodiment, the tire 1 is a pneumatic tire 1 into which air is put, and is mounted on a rim 20 .

The tire 1 also includes a carcass 1c that spans between a pair of bead cores, and an inner liner 1d that is disposed inside the carcass 1c and has an excellent function of preventing gas permeation in order to maintain air pressure. there is The carcass 1c and the inner liner 1d are arranged along the inner circumference of the tire over the beads 1a, the sidewalls 1b, and the tread 2. As shown in FIG.

The tread 2 includes a tread rubber 2b having a tread surface 2a that contacts the road surface, and a belt 2c arranged between the tread rubber 2b and the carcass 1c. The tread surface 2a has a contact patch that actually contacts the road surface, and the outer ends of the contact patch in the tire width direction D1 are called contact ends 2d and 2e. The ground contact surface is the tread surface 2a that comes into contact with the road surface when the tire 1 is mounted on a normal rim 20, placed vertically on a flat road surface with normal internal pressure, and a normal load is applied. point to

The regular rim 20 is the rim 20 defined for each tire 1 in the standard system including the standard on which the tire 1 is based. If so, it becomes "Measuring Rim".

The normal internal pressure is the air pressure determined for each tire 1 by each standard in the standard system including the standards on which the tire 1 is based. The maximum value described in "INFLATION PRESSURES", which is "INFLATION PRESSURE" for ETRTO, is 180 kPa when the tire 1 is for a passenger car.

The normal load is the load defined for each tire 1 by each standard in the standard system including the standards on which the tire 1 is based. If the value is ETRTO, it is "LOAD CAPACITY", but if the tire 1 is for a passenger car, it is set to 85% of the load corresponding to the internal pressure of 180 kPa.

As shown in FIGS. 1 and 2, the tread rubber 2b has a plurality of main grooves 3a, 3b extending in the tire circumferential direction D3. The main grooves 3a, 3b continuously extend in the tire circumferential direction D3. The main grooves 3a and 3b extend in a zigzag shape by repeating bending. However, the main grooves 3a and 3b may be configured to extend straight. Although the number of main grooves 3a and 3b is not particularly limited, it is two in this embodiment.

The main grooves 3a and 3b may have, for example, a shallow groove portion, a so-called tread wear indicator (not shown), so that the degree of wear can be known by exposing it as it wears. Further, for example, the main grooves 3a and 3b may have a groove width of 3.5% or more of the distance (dimension in the tire width direction D1) between the ground contact edges 2d and 2e. Further, for example, the main grooves 3a and 3b may have a groove width of 5.0 mm or more.

Of the plurality of main grooves 3a, 3b, the pair of outermost main grooves 3a, 3b in the tire width direction D1 are called shoulder main grooves 3a, 3b. When three or more main grooves are provided, the main groove arranged between the pair of shoulder main grooves 3a and 3b is called the center main groove. The center main groove may be configured to extend straight or zigzag. Furthermore, intermediate main grooves may be arranged between the center main groove and the shoulder main grooves to provide five or more main grooves. The mediate main groove may be configured to extend straight or zigzag like the center main groove.

The tread rubber 2b has a plurality of lands 4a-4c defined by a plurality of main grooves 3a, 3b and a pair of ground contact edges 2d, 2e. Although the number of lands 4a to 4c is not particularly limited, it is three in this embodiment.

The lands 4a and 4b defined by the shoulder main grooves 3a and 3b and the ground contact edges 2d and 2e are called shoulder lands 4a and 4b, and the land 4c defined by the shoulder main grooves 3a and 3b is called a center land 4c.

The shoulder land 4a includes a plurality of shoulder lateral grooves 51, 52 extending from the shoulder main groove 3a toward the first width direction side D11. The shoulder lateral groove 51 opens at the bent portion of the shoulder main groove 3a, and the shoulder lateral groove 52 opens at the straight portion of the shoulder main groove 3a. The shoulder land 4a has a plurality of shoulder blocks 41 divided by a plurality of shoulder lateral grooves 51, 52 in the tire circumferential direction D3.

The groove width of the shoulder lateral grooves 51, 52 is, for example, 4.5 to 8.5 mm. The groove depth of the shoulder lateral grooves 51 and 52 is, for example, 7.0 to 12.0 mm. The groove depth of the shoulder lateral grooves 51, 52 is smaller than the groove depth of the shoulder main groove 3a. In this embodiment, the groove depth of the shoulder lateral grooves 51 and 52 is 8.5 mm.

The center land 4c has a plurality of center lateral grooves 61, 62 extending from the shoulder main groove 3a toward the second width direction side D12. Both of the center lateral grooves 61 and 62 open at the straight portion of the shoulder main groove 3a. The opening of the center lateral groove 62 to the shoulder main groove 3a faces the opening of the shoulder lateral groove 52 to the shoulder main groove 3a across the shoulder main groove 3a, and the center lateral groove 62 is continuous with the shoulder lateral groove 52. It extends like The center land 4c has a plurality of center blocks 42 divided by a plurality of center lateral grooves 61, 62 in the tire circumferential direction D3.

The groove width of the center lateral grooves 61, 62 is, for example, 3.0 to 6.0 mm. Further, the groove depth of the center lateral grooves 61 and 62 is, for example, 7.0 to 12.0 mm. The groove depth of the center lateral grooves 61, 62 is smaller than the groove depth of the shoulder main groove 3a. In this embodiment, the groove depth of the center lateral grooves 61, 62 is 8.5 mm.

As shown in FIG. 3, the shoulder main groove 3a includes a groove bottom 30, groove walls 31 on the first width direction side D11, and groove walls 32 on the second width direction side D12.

The shoulder main groove 3 a has a raised bottom portion 71 at the crossing portion 33 with the shoulder lateral groove 51 . Here, when it is assumed that the shoulder lateral groove 51 extends until it reaches the groove wall 32 on the second width direction side D12 of the shoulder main groove 3a (indicated by a two-dot chain line in FIG. This is the portion where the groove 3a and the shoulder lateral groove 51 overlap.

The raised bottom portion 71 is formed by raising a portion of the groove bottom 30 of the shoulder main groove 3a. The raised bottom portion 71 is raised uniformly as a whole, and the top surface 71a of the raised bottom portion 71 is parallel to the tread surface 2a.

By providing the raised bottom portion 71 at the intersection portion 33 of the shoulder main groove 3a and the shoulder lateral groove 51, the rigidity of the intersection portion 33 where the in-plane contractive force tends to increase can be increased. As a result, in-plane contraction in the tire circumferential direction can be suppressed.

It is preferable that the raised bottom portion 71 is provided only on a portion of the intersection portion 33 . If the raised bottom portion 71 is provided on the entire crossing portion 33, the shear force of the snow column is reduced. It is preferable that the raised bottom portion 71 be provided in 50% or more of the area of the intersection portion 33 . If the bottom raised portion 71 is smaller than 50% of the area of the intersection portion 33, it is difficult to sufficiently suppress in-plane shrinkage in the tire circumferential direction. In addition, it is preferable that the raised bottom portion 71 be provided in 75% or less of the area of the intersection portion 33 . If the bottom raised portion 71 is larger than 75% of the area of the intersection portion 33, the shear force of the snow column may decrease.

A height h71 of the raised bottom portion 71 from the groove bottom 30 (also referred to as a raised height h71) is 30% or less of the groove depth d3 of the shoulder main groove 3a. A height h71 of the raised bottom portion 71 from the groove bottom 30 is preferably 20% or less of the groove depth d3 of the shoulder main groove 3a, and more preferably 15% or less of the groove depth d3 of the shoulder main groove 3a. is.

If the bottom raised portion 71 is provided, the groove volume of the shoulder main groove 3a is reduced, and there is concern that the shear force of the snow column may be reduced. % or less, it is possible to suppress a decrease in the shear force of the snow column. Thereby, in-plane shrinkage in the tire circumferential direction can be suppressed while ensuring the shearing force of the snow column.

A raised height h71 of the raised bottom portion 71 is preferably 10% or more, more preferably 15% or more, of the groove depth d3 of the shoulder main groove 3a. If the bottom-raising height h71 of the bottom-raising portion 71 is smaller than 10% of the groove depth d3 of the shoulder main groove 3a, it is difficult to sufficiently suppress in-plane shrinkage in the tire circumferential direction.

In this embodiment, the groove depth d3 of the shoulder main groove 3a is 9.5 mm, and the bottom raising height h71 of the bottom raising portion 71 is 1.0 mm. It is approximately 10% of the depth d3.

The raised bottom portion 71 is provided on the side of the shoulder main groove 3a farther from the shoulder lateral groove 51 (second width direction side D12). The raised bottom portion 71 has a substantially trapezoidal shape in plan view, and has a first side 71b and a second side 71c that extend along the tire circumferential direction D3 and face each other. The first side 71b is positioned on an extension line of one groove wall 32 of the shoulder main groove 3a. The second side 71c is positioned at the center of the shoulder main groove 3a in the groove width direction. The length of the bottom raised portion 71 in the tire circumferential direction is the longest at the second side 71c of the first width direction side D11, and gradually becomes shorter from the second side 71c toward the first side 71b of the second width direction side D12. there is In other words, the tire circumferential length of the bottom raised portion 71 becomes shorter as the distance from the shoulder lateral groove 51 increases.

The shoulder main groove 3 a has a first raised portion 72 formed by raising the groove bottom 30 so as to be adjacent to the corner of the shoulder block 41 . In this embodiment, the height of the first raised portion 72 from the groove bottom 30 of the shoulder main groove 3a is 1.8 mm.

The shoulder lateral groove 51 has a second raised portion 73 in contact with the shoulder main groove 3a. In this embodiment, the height of the second raised portion 73 from the groove bottom 30 of the shoulder main groove 3a is 7.5 mm.

The shoulder lateral groove 51 also includes an inclined portion 731 extending from the second raised portion 73 toward the first width direction side D11 while being inclined downward. The inclined portion 731 connects the top surface of the second raised portion 73 and the groove bottom of the shoulder lateral groove 51 in an inclined surface shape.

The raised bottom portion 71 surrounds a part of the groove bottom 30 of the shoulder main groove 3a adjacent to the raised bottom portion 71 together with the first raised portion 72 and the second raised portion 73 to form a concave portion 74 . Forming such recesses 74 makes it difficult for the snow that has entered the shoulder main groove 3a to escape, so that the shearing force of the snow column can be ensured.

The shoulder main groove 3 a has a raised bottom portion 75 at the crossing portion 34 with the shoulder lateral groove 52 . Here, assuming that the shoulder lateral groove 52 extends until it reaches the groove wall 32 on the second width direction side D12 of the shoulder main groove 3a (indicated by a two-dot chain line in FIG. This is the portion where the groove 3a and the shoulder lateral groove 52 overlap.

The raised bottom portion 75 is formed by raising a portion of the groove bottom 30 of the shoulder main groove 3a. The raised bottom portion 75 is raised uniformly as a whole, and the top surface 75a of the raised bottom portion 75 is parallel to the tread surface 2a.

By providing the bottom raised portion 75 at the crossing portion 34 between the shoulder main groove 3a and the shoulder lateral groove 52, the rigidity of the crossing portion 34 where the in-plane contractive force tends to increase can be increased. As a result, in-plane contraction in the tire circumferential direction can be suppressed.

Further, the raised bottom portion 75 includes an extension portion 75 d extending inside the center lateral groove 62 . By providing the extended portion 75d, the rigidity of the corner portion of the center block 42 can be increased. Thereby, in-plane shrinkage in the tire circumferential direction can be further suppressed.

It is preferable that the raised bottom portion 75 is provided only on a portion of the intersection portion 34 . If the raised bottom portion 75 is provided on the entire crossing portion 34, the shear force of the snow column is reduced. It is preferable that the raised bottom portion 75 is provided in 30% or more of the area of the intersection portion 34 . If the bottom raised portion 75 is smaller than 30% of the area of the intersection portion 34, it is difficult to sufficiently suppress in-plane shrinkage in the tire circumferential direction. In addition, it is preferable that the raised bottom portion 75 be provided in 75% or less of the area of the intersection portion 34 . If the bottom raised portion 75 is larger than 75% of the area of the intersection portion 34, the shear force of the snow column may decrease.

A height h75 of the raised bottom portion 75 from the groove bottom 30 (also referred to as a raised height h75) is 30% or less of the groove depth d3 of the shoulder main groove 3a. A height h75 of the raised bottom portion 75 from the groove bottom 30 is preferably 20% or less of the groove depth d3 of the shoulder main groove 3a, and more preferably 15% or less of the groove depth d3 of the shoulder main groove 3a. is.

If the bottom raised portion 75 is provided, the groove volume of the shoulder main groove 3a is reduced, and there is concern that the shear force of the snow column may be reduced. % or less, it is possible to suppress a decrease in the shear force of the snow column. Thereby, in-plane shrinkage in the tire circumferential direction can be suppressed while ensuring the shearing force of the snow column.

In addition, the bottom raised height h75 of the bottom raised portion 75 is preferably 10% or more, more preferably 15% or more, of the groove depth d3 of the shoulder main groove 3a. If the bottom-raising height h75 of the bottom-raising portion 75 is smaller than 10% of the groove depth d3 of the shoulder main groove 3a, it is difficult to sufficiently suppress in-plane shrinkage in the tire circumferential direction.

In this embodiment, the groove depth d3 of the shoulder main groove 3a is 9.5 mm, and the bottom raising height h75 of the bottom raising portion 75 is 1.0 mm. It is approximately 10% of the depth d3.

The raised bottom portion 75 is provided on the side of the shoulder main groove 3a farther from the shoulder lateral groove 52 (second width direction side D12). The raised bottom portion 75 is substantially L-shaped in plan view, and has a first edge 75b and a second edge 75c that extend along the tire circumferential direction D3 and face each other. The first edge 75b is positioned on the second width direction side D12, and the second edge 75c is positioned on the first width direction side D11. The length of the bottom raised portion 75 in the tire circumferential direction is the longest at the second edge 75c on the first width direction side D11, and gradually decreases from the second edge 75c toward the first edge 75b on the second width direction side D12. there is In other words, the tire circumferential length of the bottom raised portion 75 becomes shorter as the distance from the shoulder lateral groove 52 increases.

The shoulder main groove 3 a has a first raised portion 72 formed by raising the groove bottom 30 so as to be adjacent to the corner of the shoulder block 41 . In this embodiment, the height of the first raised portion 72 from the groove bottom 30 of the shoulder main groove 3a is 1.8 mm.

The shoulder lateral groove 52 has a second raised portion 73 in contact with the shoulder main groove 3a. In this embodiment, the height of the second raised portion 73 from the groove bottom 30 of the shoulder main groove 3a is 7.5 mm.

In addition, the shoulder lateral groove 52 includes an inclined portion 731 extending from the second raised portion 73 toward the first width direction side D11 while being inclined downward. The inclined portion 731 connects the top surface of the second raised portion 73 and the groove bottom of the shoulder lateral groove 52 in an inclined surface shape.

The raised bottom portion 75 surrounds a portion of the groove bottom 30 of the shoulder main groove 3a adjacent to the raised bottom portion 75 together with the two first and second raised portions 72 and 73 to form a recess 76. As shown in FIG. Forming such recesses 76 makes it difficult for the snow that has entered the shoulder main groove 3a to escape, so that the shearing force of the snow column can be ensured.

The center lateral groove 62 has a third raised portion 751 connected to the extended portion 75 d of the raised bottom portion 75 . In this embodiment, the height of the third raised portion 751 from the groove bottom 30 of the shoulder main groove 3a is 4 mm.

As described above, the pneumatic tire 1 according to the present embodiment has a plurality of main grooves 3a and 3b formed in the tread 2 so as to extend along the tire circumferential direction D3. Shoulder main grooves 3a and shoulder lateral grooves 51, 52 extending outward in the tire width direction from the shoulder main grooves 3a are provided. The height h71, h75 of the raised bottom portions 71, 75 is 30% or less of the depth d3 of the shoulder main groove 3a.

According to this configuration, by providing the bottom raised portions 71 and 75 at the intersections 33 and 34 of the shoulder main groove 3a and the shoulder lateral grooves 51 and 52, the rigidity of the intersections 33 and 34 where the in-plane contraction force tends to increase is increased. be able to. Further, by setting the heights h71, h75 of the raised bottom portions 71, 75 to 30% or less of the groove depth d3 of the shoulder main groove 3a, it is possible to suppress the decrease in the shear force of the snow column. As a result, it is possible to suppress the in-plane contraction in the tire circumferential direction while ensuring the shear force of the snow column.

In addition, in the pneumatic tire 1 according to the present embodiment, the bottom raised portions 71 and 75 are provided on the far side of the shoulder main groove 3a from the shoulder lateral grooves 51 and 52, and the bottom raised portions 71 and 75 are provided in the circumferential direction of the tire. The configuration is such that the length becomes shorter as the distance from the shoulder lateral grooves 51 and 52 increases.

According to this configuration, it is possible to increase the rigidity of the central portion in the groove width direction of the shoulder main groove 3a, where the in-plane contraction force tends to increase, so that the in-plane contraction in the tire circumferential direction can be effectively suppressed.

Further, in the pneumatic tire 1 according to the present embodiment, the raised bottom portions 71 and 75 are provided only at part of the intersection portions 33 and 34 .

According to this configuration, it is possible to suppress a decrease in the shearing force of the snow column due to the raised bottom portions 71 and 75 .

In addition, in the pneumatic tire 1 according to the present embodiment, the raised bottom portions 71 and 75 extend the groove bottom 30 of the shoulder main groove 3a adjacent to the raised bottom portions 71 and 75 together with the raised portions 72 and 73. It is configured such that recesses 74 and 76 are formed surrounding it.

By forming the concave portions 74 and 76, it becomes difficult for snow that has entered the shoulder main groove 3a to escape, so that the shearing force of the snow column can be ensured.

Note that the pneumatic tire 1 is not limited to the configuration of the embodiment described above, nor is it limited to the effects described above. Further, the pneumatic tire 1 can of course be modified in various ways without departing from the gist of the present invention. For example, each configuration, each method, etc. of the plurality of embodiments described above may be arbitrarily adopted and combined, and further, one or more of the configurations, methods, etc. according to the various modifications described below may be arbitrarily selected. , of course, may be employed in the configurations, methods, and the like according to the above-described embodiments.

(1) In the pneumatic tire 1 according to the above-described embodiment, the bottom raised portions 71, 75 are provided on the far side of the shoulder main groove 3a from the shoulder lateral grooves 51, 52, and the tire circumference of the bottom raised portions 71, 75 is The length in the direction becomes shorter as the distance from the shoulder lateral grooves 51 and 52 increases. However, the pneumatic tire 1 is not limited to such a configuration. For example, the raised bottom portions 71 and 75 may be provided on the side of the shoulder main groove 3a closer to the shoulder lateral grooves 51 and 52, and the length of the raised bottom portions 71 and 75 in the tire circumferential direction may be in the tire width direction D1. It may be constant.

(2) In the pneumatic tire 1 according to the above embodiment, the raised bottom portions 71 and 75 are provided only at part of the intersection portions 33 and 34 . However, the pneumatic tire 1 is not limited to such a configuration. For example, the raised bottom portions 71 and 75 may be provided on all of the intersection portions 33 and 34 .

(3) In the pneumatic tire 1 according to the above-described embodiment, the raised bottom portions 71 and 75 extend from the groove bottom 30 of the shoulder main groove 3a adjacent to the raised bottom portions 71 and 75 to the plurality of raised portions 72 and 73. , forming recesses 74 and 76. However, the pneumatic tire 1 is not limited to such a configuration. For example, even if the groove bottom 30 of the shoulder main groove 3a adjacent to the bottom raised portions 71, 75 is not completely surrounded, by providing the bottom raised portions 71, 75, the bottom raised portions 71, 75 and the bottom raised portions 71, 75 Since unevenness is formed by the groove bottom 30 of the shoulder main groove 3a adjacent to the shoulder main groove 3a, the shear force of the snow column can be ensured.

(4) In the pneumatic tire 1 according to the above embodiment, the raised bottom portions 71 and 75 are polygonal in plan view. However, the pneumatic tire 1 is not limited to such a configuration. For example, as shown in FIG. 6, the raised bottom portion 77 may be composed of a plurality of ridges extending along the tire circumferential direction D3. In addition, in the example shown in FIG. 6 , a raised bottom portion 77 is provided instead of the raised bottom portion 71 , but a raised bottom portion 77 may be provided instead of the raised bottom portion 75 . Further, a raised bottom portion 77 may be provided in place of both the raised bottom portion 71 and the raised bottom portion 75 .

(5) Although the shoulder main grooves 3a have been described in the above embodiment, the tire 1 of the present embodiment is a tire in which the mounting direction to the vehicle is not specified, and the shoulder main grooves 3b and the shoulder main grooves 3a are not specified. have the same shape. Therefore, it is preferable that the raised bottom portions 71 and 75 are also provided in the same shape in both the shoulder main grooves 3a and 3b. However, this embodiment can also be applied to a tire having a so-called asymmetrical pattern in which the mounting direction to the vehicle is specified. Alternatively, the shoulder main grooves 3a, 3b may have different shapes of the raised bottom portions 71, 75, and the heights h71, h75 of the raised bottom portions 71, 75 from the groove bottom 30 may be set by the shoulder main grooves 3a, 3b. can be different.

1 Pneumatic tire 2 Tread 2a Tread surface 2d Grounding edge 2e Grounding edge 3a Main groove (shoulder main groove) 3b Main groove (shoulder main groove) 4a Land (shoulder) land), 4b... land (shoulder land), 4c... land (center land), 30... groove bottom of shoulder main groove, 33... intersection of shoulder main groove with shoulder lateral groove, 34... shoulder lateral groove of shoulder main groove and 41...Shoulder block 42...Center block 51...Shoulder lateral groove 52...Shoulder lateral groove 61...Center lateral groove 62...Center lateral groove 71...Bottom raised part 72...First raised part 73...Second Second raised portion 74 ... recessed portion 75 ... raised bottom portion 76 ... recessed portion 77 ... raised bottom portion d3 ... groove depth of shoulder main groove h71 ... bottom raised height h75 ... bottom raised height D1 ... tire width direction , D11... first side in tire width direction, D12... second side in tire width direction, D2... tire radial direction, D3... tire circumferential direction, S1... tire equatorial plane

Claims (4)

a shoulder main groove arranged on the outermost side in the tire width direction among a plurality of main grooves formed in the tread so as to extend along the tire circumferential direction;
a shoulder lateral groove extending outward in the tire width direction from the shoulder main groove,
The shoulder main groove has a raised bottom portion at the intersection with the shoulder lateral groove, and the height of the raised bottom portion is 30% or less of the groove depth of the shoulder main groove. pneumatic tires. 2. The method according to claim 1, wherein the raised bottom portion is provided on a side of the shoulder main groove farther from the shoulder lateral groove, and the length of the raised bottom portion in the tire circumferential direction decreases as the distance from the shoulder lateral groove increases. pneumatic tires. The pneumatic tire according to claim 1 or 2, wherein the raised bottom portion is provided only at a portion of the intersection portion. 4. The raised bottom portion according to any one of claims 1 to 3, wherein the raised bottom portion surrounds a portion of the groove bottom of the shoulder main groove adjacent to the raised bottom portion together with a plurality of raised portions to form a recess. pneumatic tires.

Images