JP7261008B2 - pneumatic tire - Google Patents

Description

The present invention relates to pneumatic tires.

Conventionally, a pneumatic tire having a plurality of blocks divided by grooves in the tread and having rubber connecting means at the bottom of the grooves for connecting specific portions of the blocks adjacent to each other with the grooves therebetween is known (for example, Patent Reference 1).

The blocks have various shapes, and the shapes of the specific parts connected by the rubber connecting means may also be different. If the shape of the specific portion is different, the rigidity is also different, which causes uneven wear.

However, the rubber connecting means of the conventional pneumatic tire does not have the function of canceling the difference in rigidity at a specific portion of the blocks to be connected.

Japanese Patent Publication No. 2016-531806

SUMMARY OF THE INVENTION An object of the present invention is to provide a pneumatic tire capable of suppressing the occurrence of uneven wear by reducing the difference in rigidity due to the difference in shape between specific portions of adjacent blocks.

According to one aspect of the present invention, as a means for solving the above problems, a plurality of grooves formed in a tread portion and a plurality of blocks partitioned by the grooves are provided, and the blocks are arranged adjacent to each other in a predetermined direction. mating first and second blocks, wherein the grooves are positioned between the first and second blocks and laterally of the first and second blocks; and a second groove where the first grooves meet, the first block having a first region formed at an obtuse angle by the first groove and the second groove, the second block comprising: a second region formed at an acute angle by the first groove portion and the second groove portion; a bridge connecting the first region and the second region at a groove bottom of the first groove portion; the height dimension from the groove bottom increases from the first region toward the second region, and the width dimension of the bridge increases from the first region toward the second region; Provide inboard tires.

With this configuration, the first region and the second region can be connected and reinforced by the bridge. Moreover, since the height dimension of the bridge from the groove bottom is increased on the side of the second region where the rigidity is inferior to that of the first region, it is possible to compensate for the difference in rigidity between the first region and the second region. That is, it is possible to suppress the occurrence of uneven wear between the first region and the second region, which are specific portions of the block.
In addition, due to the configuration "the width dimension of the bridge increases from the first region to the second region", the rigidity difference between the first region and the second region is reduced to suppress the occurrence of uneven wear. can.

The side edge of the bridge on the side of the second groove may be located within a range of 0 mm or more and 10 mm or less from the second groove.

The bridge is 0.2×D≦d1≦0.4×D, where D is the depth of the groove and d1 is the height of the first end of the first region from the bottom of the groove. is preferably satisfied.

The bridge is 0.4×D≦d2≦0.6×D, where D is the depth of the groove and d2 is the height of the second end of the second region from the bottom of the groove. is preferably satisfied.

Preferably, the bridge has a planar upper surface whose height dimension from the groove bottom gradually increases from the first region to the second region.

Preferably, the bridge has a stepped upper surface whose height dimension from the groove bottom increases stepwise from the first region to the second region.

When the angle of the first region is θ1 and the angle of the second region is θ2, it is preferable to satisfy −65°≦θ2−θ1≦0°.

With this configuration, it is possible to reinforce with a bridge suitable for the difference in rigidity between the blocks in the first region and the second region, and to achieve both drainage and uneven wear resistance.
Another aspect of the present invention includes a plurality of grooves formed in a tread portion, and a plurality of blocks partitioned by the grooves, the blocks comprising a first block and a second block adjacent to each other in a predetermined direction. wherein the grooves include a first groove located between the first block and the second block, and a second groove located laterally of the first block and the second block where the first grooves join together. a groove portion, wherein the first block has a first region formed at an obtuse angle by the first groove portion and the second groove portion; and the second block has an acute angle formed by the first groove portion and the second groove portion. and a bridge connecting the first region and the second region at the groove bottom of the first groove, wherein the bridge extends from the first region to the second region. The height dimension from the groove bottom increases toward the bridge, and the bridge has a stepped upper surface in which the height dimension from the groove bottom increases stepwise from the first region to the second region. Offer pneumatic tires.

According to the present invention, it is possible to reduce the difference in rigidity due to the difference in shape between specific portions of adjacent blocks, thereby suppressing the occurrence of uneven wear.

FIG. 2 is an exploded view showing part of the tread portion of the pneumatic tire according to the first embodiment. FIG. 2 is a cross-sectional view taken along the line AA of FIG. 1; BB line cross-sectional view of FIG. CC line sectional view of FIG. FIG. 7 is an exploded view showing a part of the tread portion of the pneumatic tire according to the second embodiment; FIG. 6 is a partial plan view showing another example of the bridge shown in FIG. 1 or 5; FIG. 6 is a partial plan view showing another example of the bridge shown in FIG. 1 or 5; FIG. 8 is a cross-sectional view taken along line DD of FIG. 7; FIG. 6 is a partial plan view showing another example of the bridge shown in FIG. 1 or 5; FIG. 10 is a cross-sectional view taken along line EE of FIG. 9; FIG. 6 is a partial plan view showing another example of the bridge shown in FIG. 1 or 5; FIG. 11 is a cross-sectional view taken along line FF of FIG. 11; FIG. 6 is a partial plan view showing another example of the bridge shown in FIG. 1 or 5; FIG. 13 is a cross-sectional view along the line GG of FIG. FIG. 6 is a partial plan view showing another example of the bridge shown in FIG. 1 or 5; FIG. 15 is a cross-sectional view taken along line HH of FIG. FIG. 6 is a partial plan view showing another example of the bridge shown in FIG. 1 or 5; FIG. 6 is a partial plan view showing another example of the bridge shown in FIG. 1 or 5; FIG. 19 is a sectional view taken along the line II of FIG. 17 or FIG. 18;

Hereinafter, embodiments of the present invention will be described with reference to the accompanying drawings. It should be noted that the following description is essentially merely an example, and is not intended to limit the present invention, its applications, or its uses. Moreover, the drawings are schematic diagrams for facilitating understanding of the invention, and the ratios of the respective dimensions do not necessarily match the actual ones.

(First embodiment)
FIG. 1 is a developed view showing a part of the tread portion 1 of the pneumatic tire according to the first embodiment.

A plurality of blocks 4 are formed in the tread portion 1 by a plurality of main grooves 2 extending in the tire circumferential direction and a plurality of lateral grooves 3 extending in the tire width direction. The lateral grooves 3 gradually incline to one side in the tire circumferential direction toward the outside in the tire width direction. The depth dimensions of the main groove 2 and the lateral groove 3 are the same. Here, the lateral groove 3 is the first groove portion and the main groove 2 is the second groove portion.

The side surfaces of the blocks 4 forming part of the main grooves 2 and the lateral grooves 3 are formed in a planar shape perpendicular to the groove bottom. An edge 5 is formed on the upper surface of each block 4 at the boundary with the side surface. The area surrounded by the four edges 5 is a parallelogram in plan view. Therefore, a first region 6 in which the angle θ1 formed by the two edges 5 is an obtuse angle and a second region 7 in which the angle θ2 formed by the two edges 5 is an acute angle are formed.

The blocks 4 adjacent in the tire circumferential direction with the lateral grooves 3 interposed therebetween have their main groove side regions connected to each other by bridges 8 formed in the groove bottoms of the lateral grooves 3 . One end of the bridge 8 is connected to the first region 6 of the block 4 (first block 4a) located on the upper side in FIG. 1, and the other end is connected to the block 4 (second block 4b) located on the lower side. is connected to the second region 7 of the By connecting the blocks to each other with the bridge 8, it is possible to reinforce the area of the block 4 which has low rigidity and is easily deformed.

As shown in FIG. 3, one side surface (first side surface 8a) of the bridge 8 is formed along the main groove 2. As shown in FIG. However, the position (first side surface position FP) of the first side surface 8 a in plan view may be inside the lateral groove 3 . Specifically, the first side surface position FP may be within the range S between the boundary line BL between the main groove 2 and the lateral groove 3 and the position 10 mm into the lateral groove 3 . By setting the first side position FP within this range, each area of the block 4 can be sufficiently reinforced. As shown in FIG. 4, the other side surface (second side surface 8b) of the bridge 8 is an inclined surface that gradually slopes into the lateral groove 3 downward from the upper surface. The boundary position between the second side surface and the upper surface in plan view may be a position where the area of the upper surface is larger than that of the inclined surface.

The upper surface of the bridge 8 differs in height dimension from the groove bottom between the first region 6 side of the first block 4a and the second region 7 side of the second block 4b. That is, as shown in FIG. 2, the bridge 8 divides the lateral groove 3 into two in the groove width direction, and the second bridge portion 8d on the second region 7 side is larger than the first bridge portion 8c on the first region 6 side. is formed high. A height dimension d1 of the first bridge portion 8c from the groove bottom is set to satisfy 0.2×D≤d1≤0.4×D where D is the depth dimension of the lateral groove 3. . By setting the height dimension of the first bridge portion 8c within this range, it is possible to improve the block rigidity while ensuring drainage performance at the initial stage of wear. A height dimension d2 of the second bridge portion 8d from the groove bottom is set to satisfy 0.4×D≦d2≦0.6×D. By setting the height dimension of the second bridge portion 8d within this range, it is possible to reinforce the first bridge portion 8c while ensuring water drainage in the final stage of wear.

A difference in rigidity occurs between the first region 6 and the second region 7 due to the difference in shape. The rigidity of the first region 6 formed at an obtuse angle is greater than the rigidity of the second region 7 formed at an acute angle. Therefore, when the tread portion 1 contacts the road surface, the second region 7 deforms more easily than the first region 6 . Therefore, the second area 7 is more likely to wear than the first area 6, causing uneven wear. In this embodiment, as described above, the height dimension of the second bridge portion 8d is set larger than that of the first bridge portion 8c. As a result, the rigidity of the second region 7 of the second block 4b, which is less rigid than that of the first region 6 of the first block 4a, can be increased, and the difference in rigidity between the two can be suppressed.

According to the pneumatic tire according to the first embodiment, the following effects are obtained.
Between blocks 4 adjacent to each other with lateral grooves 3 interposed therebetween, bridges 8 connect corner regions of blocks 4 whose rigidity is weaker than other portions. Therefore, when looking at one block 4, the balance of rigidity as a whole is stabilized.
In particular, the height dimension from the groove bottom of the bridge 8 is compared to the height dimension from the groove bottom of the second bridge portion 8d connected to the second region 7 compared to the first bridge portion 8c connected to the first region 6. is set to be large. Thereby, the difference in rigidity between the first region 6 and the second region 7 adjacent to each other with the lateral groove 3 interposed therebetween can be suppressed.
Therefore, it is possible to prevent uneven wear of the blocks 4 due to contact with the ground during running on the road surface, particularly uneven wear between the first region 6 and the second region 7 between the adjacent blocks 4 .

(Second embodiment)
FIG. 5 is a developed view showing part of the tread portion 9 of the pneumatic tire according to the second embodiment.

The tread portion 9 is formed with main grooves 10 extending straight in the tire circumferential direction and zigzag fine grooves 11 extending in a zigzag shape. In addition, the tread portion 9 includes a first outer slit 12 that is inclined outward in the tire width direction from the main groove 10 in one direction in the tire circumferential direction, and a first outer slit 12 that branches off from the first outer slit 12 and extends outward in the tire width direction. and a second outer slit 13 inclined in the other circumferential direction of the tire. Further, the tread portion 9 is formed with an inner slit 14 extending from the main groove 10 toward the inner side in the tire width direction and extending through the zigzag narrow groove 11 . Here, the first outer slit 12 is the first groove and the main groove 10 is the second groove.

A center block 15 is defined by the main groove 10 , the first outer slit 12 and the second outer slit 13 . A plurality of center blocks 15 are arranged in the tire circumferential direction along the main groove 10 (hereinafter, the center block 15 located on the upper side in FIG. 15 is referred to as a second block 15b).

5, the outer edge of the center block 15 has a first circular arc portion 16, a first linear portion 17, a second circular arc portion 18 and a third circular arc portion 19 continuing from the upper end position on the main groove side. A second linear portion 20 extends from the first outer slit 12 positioned below the center block 15 to the third arc portion 19 along the second outer slit 13 . A fourth arc portion 21 continues to the second straight portion 20 along the first outer slit 12 on the upper side and merges with the first arc portion 16 . The center block 15 protrudes further toward the main groove than the first linear portion 17 in a range from the second circular arc portion 18 to a part of the third circular arc portion 19 .

In the first block 15a, the angle θ1 formed between the virtual line VL extending from the first linear portion 17 and the tangent line TL passing through the virtual intersection point VN of the third circular arc portion 19 (the intersection of the virtual line VL and the third circular arc portion 19). is an obtuse angle. The portion forming this obtuse angle is the first region 22 . In the second block 15b, a first tangent line TL1 on the first arc portion side passing through the intersection of the first arc portion 16 and the fourth arc portion 21 of the second block 15b, and a second tangent line TL2 on the fourth arc portion side. The angle θ2 formed is an acute angle. The portion forming this acute angle is the second region 23 . In this way, the angle of each area is defined by the angle formed by the straight line and the tangent to the arc passing through the intersection of the straight line and the circular arc, if the straight line and the circular arc intersect. If there is, it is defined by the angle formed by the tangents on each arc passing through the intersection of the two.

An outer intermediate block 24 is defined by the first outer slit 12 and the second outer slit 13 . The outer intermediate blocks 24 are adjacent to the center block 15 on the outer side in the tire width direction, and are arranged in plurality in the tire circumferential direction. An outer shoulder block 25 is arranged on the outer side in the tire width direction of the outer mediate block 24 with the second outer slit 13 interposed therebetween. A plurality of outboard shoulder blocks 25 are also arranged in the tire circumferential direction.

The inner intermediate block is defined by the main groove 10 , the zigzag narrow groove 11 and the inner slit 14 . A plurality of inner intermediate blocks are arranged along the main groove 10 in the tire circumferential direction. A plurality of inner shoulder blocks are arranged in the tire circumferential direction on both sides of the zigzag narrow groove 11 on the inner side of the inner intermediate block in the tire width direction.

The center blocks 15 adjacent in the tire circumferential direction with the first outer slit 12 interposed therebetween are connected to each other by a bridge 8 formed at the groove bottom of the first outer slit 12 . One end of the bridge 8 is connected to the first region 22 of the first block 15a, and the other end is connected to the second region 23 of the second block 15b.

One side surface (first side surface) of the bridge 8 is located on the extension line of the first circular arc portion 16 of the second block. An extension line of this first circular arc portion 16 is a boundary line BL between the main groove 10 and the first outer slit 12 . As in the first embodiment, the position of the first side surface in plan view (first side surface position) may be inside the lateral groove 3 . The other side surface (second side surface) of the bridge 8 is also formed of an inclined surface as in the first embodiment.

The upper surface of the bridge 8 has the configuration shown in FIG. 2, as in the first embodiment. That is, the height dimension from the groove bottom of the second bridge portion 8d on the second region 23 side is set to be larger than the height dimension from the groove bottom of the first bridge portion 8c on the first region 22 side. It is

In the pneumatic tire according to the second embodiment, as in the first embodiment, the bridge 8 connects the first region 22 of the first block 15a and the second region 23 of the second block. Therefore, the portion of the block 4 having lower rigidity than the other portions can be reinforced, and the rigidity balance as a whole can be adjusted.
In particular, since the height dimension from the groove bottom of the bridge 8 is made higher on the second region 23 side than on the first region 22 side, the first region 22 and the first region 22 facing each other with the first outer slit 12 interposed therebetween A difference in rigidity between the two regions 23 can be suppressed.
Therefore, it is possible to prevent uneven wear of the center block 15 due to contact with the ground while traveling on a road surface.

The present invention is not limited to the configurations described in the above embodiments, and various modifications are possible.

In the above-described embodiment, the height dimension of the bridges 8 is made different to equalize the rigidity at specific portions of the adjacent blocks 4, but it may be made compatible by making the width dimension different. . That is, the bridge 8 shown in FIG. 6 is formed such that the width dimension gradually increases from the first region 6 (width dimension w1) toward the second region 7 (width dimension w2). With this configuration, similarly to the bridge 8 described in the above embodiment, the difference in rigidity between the first region 6 and the second region 7 can be suppressed to prevent uneven wear. By changing both the height dimension and the width dimension of the bridge 8, a similar effect can be obtained without significantly changing the dimension.

In the above embodiment, the bridge 8 is composed of the first bridge portion 8c and the second bridge portion 8d having different height dimensions, but it can also be constructed as follows.

In FIG. 7, the upper surface of the bridge 8 is formed of an inclined surface whose height dimension gradually increases from the first region 6 toward the second region 7 . As shown in FIG. 8, the height dimension d1 at the confluence position of the inclined surface and the first region 6 is 0.2×D≤d1≤0.4×D where D is the depth dimension of the lateral groove 3. set to your satisfaction. A height dimension d2 at the confluence position of the inclined surface and the second region 7 is set to satisfy 0.4×D≦d2≦0.6×D.
According to this configuration, it is possible to prevent rapid changes in the groove volume and contact area due to wear.

In FIG. 9, the upper surfaces of the bridges 8 are configured such that the first bridge portion 8c has an inclined surface and the second bridge portion 8d has a flat surface. As shown in FIG. 10, the inclined surface of the first bridge portion 8c is formed such that the height dimension from the groove bottom gradually increases from the first region 6 toward the second bridge portion 8d. The height dimension d1 of the confluence position of the inclined surface and the first region 6 is set to satisfy 0.2×D≦d1≦0.4×D (D is the depth dimension of the lateral groove 3). . A height dimension d2 of the flat surface is set to satisfy 0.4×D≦d2≦0.6×D.
According to this configuration, the block rigidity of the second area can be further increased relative to that of the first area, thereby reducing the difference in block rigidity.

Conversely, in FIG. 11, the upper surface of the bridge 8 is configured such that the first bridge portion 8c has a flat surface and the second bridge portion 8d has an inclined surface. As shown in FIG. 12, the inclined surface of the second bridge portion 8d is formed such that the height dimension gradually increases from the flat surface of the first bridge portion 8c toward the second bridge portion 8d. The height dimension d1 of the flat surface is set to satisfy 0.2×D≤d1≤0.4×D (D is the depth dimension of the lateral groove 3). A height dimension d2 at the confluence position of the inclined surface and the second region 7 is set to satisfy 0.4×D≦d2≦0.6×D.
According to this configuration, the block rigidity of the second region is further increased with respect to the block rigidity of the first region to reduce the difference in block rigidity. be able to.

In FIG. 13 , the top surface of the bridge 8 is formed in a stepped shape that rises stepwise from the first region 6 toward the second region 7 . As shown in FIG. 14, the height dimension d1 of the lowest position of the upper surface is set to satisfy 0.2×D≤d1≤0.4×D (D is the depth dimension of the lateral groove 3). there is A height dimension d2 of the highest position of the upper surface is set to satisfy 0.4×D≦d2≦0.6×D.
According to this configuration, the groove volume and contact area due to wear can be changed stepwise.

In FIG. 15, the upper surface of the bridge 8 is formed stepwise in the first bridge portion 8c and is flat in the second bridge portion 8d. As shown in FIG. 16, the height dimension d1 of the lowest position of the first bridge portion 8c satisfies 0.2×D≦d1≦0.4×D (D is the depth dimension of the lateral groove 3). is set to A height dimension d2 of the flat surface is set to satisfy 0.4×D≦d2≦0.6×D.
According to this configuration, especially when the block rigidity of the second region is smaller than that of the first region, the block rigidity of the second region is increased to reduce the difference in block rigidity, while the groove volume and contact area due to wear are stepped. can change dramatically.

In FIGS. 17 and 18, the upper surface of the bridge 8 is composed of a flat surface and stepped portions. The step portion in FIG. 17 converges at one point on the main groove side. The stepped portion in FIG. 18 is narrower than the width inside the lateral groove 3 on the main groove side. As shown in FIG. 19, the height dimension d1 of the lowest position of the stepped portion is set to satisfy 0.2×D≦d1≦0.4×D (D is the depth dimension of the lateral groove 3). ing. A height dimension d2 of the flat surface is set to satisfy 0.4×D≦d2≦0.6×D.
According to this configuration, it is possible to reinforce the tip end side of the corner portion of the second region and to more effectively reduce the occurrence of uneven wear.

In the above-described embodiment, the boundary portion of the side surface with respect to the upper surface of the block 4 is configured by the edge 5, but chamfering (such as a corner surface or a round surface) may be performed.

In the above embodiment, the case where the blocks adjacent to each other across the lateral groove 3 or the first outer slit 12 are connected by the bridge 8 has been described. , this portion may be connected by a bridge 8. FIG. For example, as shown in FIG. 1, a bridge 8 may connect the first region 6 and the second region 7 of the blocks 4 adjacent to each other with the main groove 2 interposed therebetween. In this case, the rigidity variation can be eliminated by increasing the height and width of the bridge 8 on the second area side, which has lower rigidity than the first area side. According to this, uneven wear occurs due to the difference in the amount of wear during cornering based on the difference in rigidity between the first region 6 of one block 4 and the second region 7 of the other block 4. can be prevented.

DESCRIPTION OF SYMBOLS 1... Tread part 2... Main groove 3... Lateral groove 4... Block 5... Edge 6... First area 7... Second area 8... Bridge 9... Tread part 10... Main groove 11... Zigzag thin groove 12... First outer slit 13 2nd outer slit 14 inner slit 15 center block 16 first arc portion 17 first straight portion 18 second arc portion 19 third arc portion 20 second straight portion 21 fourth arc portion 22 ... First region 23 ... Second region 24 ... Outer intermediate block 25 ... Outer shoulder block

Claims (7)

a plurality of grooves formed in the tread;
a plurality of blocks partitioned by the grooves;
with
the blocks include a first block and a second block adjacent to each other in a predetermined direction;
The groove is
a first groove located between the first block and the second block;
a second groove portion located laterally of the first block and the second block, where the first groove portions join;
including
The first block has a first region formed at an obtuse angle by the first groove and the second groove,
the second block has a second region formed at an acute angle by the first groove and the second groove;
Having a bridge connecting the first region and the second region at the groove bottom of the first groove,
the bridge has a height dimension from the groove bottom that increases from the first region toward the second region;
The pneumatic tire, wherein the width of the bridge increases from the first region toward the second region. a plurality of grooves formed in the tread;
a plurality of blocks partitioned by the grooves;
with
the blocks include a first block and a second block adjacent to each other in a predetermined direction;
The groove is
a first groove located between the first block and the second block;
a second groove portion located laterally of the first block and the second block, where the first groove portions join;
including
The first block has a first region formed at an obtuse angle by the first groove and the second groove,
the second block has a second region formed at an acute angle by the first groove and the second groove;
Having a bridge connecting the first region and the second region at the groove bottom of the first groove,
the bridge has a height dimension from the groove bottom that increases from the first region toward the second region;
The pneumatic tire, wherein the bridge has a stepped upper surface whose height dimension from the groove bottom increases stepwise from the first region to the second region. The pneumatic tire according to claim 1 or 2, wherein a side edge of the bridge on the side of the second groove portion is located within a range of 0 mm or more and 10 mm or less from the second groove portion. When the depth dimension of the groove portion of the bridge is D, and the height dimension from the bottom of the groove at the first end on the side of the first region is d1,
0.2×D≦d1≦0.4×D
The pneumatic tire according to any one of claims 1 to 3, satisfying When the depth dimension of the groove portion of the bridge is D, and the height dimension from the bottom of the second end on the second region side is d2,
0.4×D≦d2≦0.6×D
The pneumatic tire according to any one of claims 1 to 4, satisfying 6. The bridge according to any one of claims 1, 3 to 5, wherein said bridge has a planar upper surface whose height dimension from the groove bottom gradually increases from said first region to said second region. pneumatic tires. When the angle of the first region is θ1 and the angle of the second region is θ2,
-65°≤θ2-θ1≤0°
The pneumatic tire according to any one of claims 1 to 6, satisfying

Images