JP2021094991A - tire - Google Patents

Abstract

To provide a tire that can make both on-snow performance and abrasion resistance compatible at higher level, while adopting a tread pattern having land part blocks aggregated in a center land part region.SOLUTION: A pneumatic tire 10 has a center land part region CT1 sectioned by a pair of circumferential main grooves 71 and 72 extending in a tire circumferential direction. In the center land part region are provided land part blocks 100 and 200, sectioned by a width-directional groove extending in a tire width direction, in which only circumferential narrow grooves 61 and 62 which are smaller in groove width than the circumferential main grooves and which extend in the tire circumferential direction, or constitutive portions extending in the tire circumferential direction are not formed. On surfaces of the land part blocks which contact a road surface are provided protrusion parts protruding toward outside in a tire radial direction.SELECTED DRAWING: Figure 1

Description

The present invention relates to a tire suitable for traveling on an ice-snow road surface.

Conventionally, in a pneumatic tire such as a studless tire suitable for running on an ice-snow road surface (hereinafter, abbreviated as a tire as appropriate), the circumferential direction is formed in a central land region defined by a pair of circumferential main grooves extending in the circumferential direction of the tire. A tread pattern is known in which a circumferential narrow groove having a groove width narrower than that of the main groove and a land block defined by a width direction groove extending in the tire width direction are provided (see Patent Document 1).

According to such a tire, the land blocks partitioned by the circumferential narrow grooves having a narrow groove width are in an aggregated state in the tire width direction and can support each other with the adjacent land blocks. It is easy to maintain the rigidity of the part block. Therefore, it is said that both running performance on ice and snow road surfaces (hereinafter referred to as snow performance) and wear resistance can be achieved at the same time.

International Publication No. 2015/056573

However, in the case of the tread pattern as described above, since the land block is partitioned by the circumferential narrow groove having a narrow groove width, the ground pressure of the land block tends to be low in the central land region, and the ice and snow road surface is struck. There is a problem that the edge component that contributes to scratching performance is inhibited.

Therefore, the present invention has been made in view of such a situation, and while adopting a tread pattern in which land blocks are aggregated in the central land region, snow performance and wear resistance are further enhanced. The purpose is to provide compatible tires.

One aspect of the present invention has a central land region (central land region CT1) partitioned by a pair of circumferential grooves (circumferential main grooves 71, 72) extending in the tire circumferential direction, and the central land region. The groove width is narrower than the circumferential groove, and only the circumferential fine groove (circumferential fine groove 61, 62) extending in the tire circumferential direction is formed, or the groove component extending in the tire circumferential direction is not formed. A land block (for example, land blocks 100, 200) partitioned by a width groove (width groove 300) extending in the tire width direction is provided, and the tire diameter is provided on the surface of the land block in contact with the road surface. A tire (pneumatic tire 10) provided with protrusions (protrusions 160, 260) that are convex toward the outside in the direction.

According to the tire described above, it is possible to achieve both snow performance and wear resistance at a higher level while adopting a tread pattern in which land blocks are aggregated in the central land region.

FIG. 1 is a partially plan view of the tread of the pneumatic tire 10. FIG. 2 is a partially enlarged plan view of the block row 30. FIG. 3 is a side view of the land block 100 from the F3 direction shown in FIG. FIG. 4 is a partially enlarged plan view of the block row 30A according to the modified example. FIG. 5 is a partially enlarged plan view of the block row 30B according to another modified example.

Hereinafter, embodiments will be described with reference to the drawings. The same functions and configurations are designated by the same or similar reference numerals, and the description thereof will be omitted as appropriate.

(1) Overall Schematic Configuration of Tire FIG. 1 is a partially plan-developed view of the tread of the pneumatic tire 10 according to the present embodiment. As shown in FIG. 1, the pneumatic tire 10 has a tread 20 in contact with the road surface.

The tread 20 is formed with a tread pattern according to the required performance for the pneumatic tire 10. In the present embodiment, the pneumatic tire 10 is a studless tire that can be suitably used for a truck / bus (TB). The studless tire may be called a snow tire, a winter tire, or the like. Alternatively, the pneumatic tire 10 may be a so-called all-season tire that can be used not only in winter but throughout the four seasons.

Further, the pneumatic tire 10 is not necessarily used for trucks and buses, and may be used for other vehicle types such as passenger cars, vans and light trucks.

The tread 20 is provided with a plurality of block rows extending in the tire circumferential direction. Specifically, the tread 20 is provided with a block row 30, a block row 40, and a block row 50.

The block row 30 is provided at a position including the tire equatorial line CL. The block row 30 is a block row partitioned by the circumferential groove 61 and the circumferential groove 62. The block row 40 and the block row 50 are provided outside the block row 30 in the tire width direction.

A circumferential main groove 71 extending in the tire circumferential direction is formed on the outer side of the block row 40 in the tire width direction. Similarly, a circumferential main groove 72 extending in the tire circumferential direction is formed on the outer side of the block row 30 in the tire width direction. In the present embodiment, the circumferential main groove 71 and the circumferential main groove 72 are linear. However, the circumferential main groove 71 and the circumferential main groove 72 do not necessarily have to be linear, such as coasting slightly in the tire width direction. The circumferential main groove 71 and the circumferential main groove 72 may be simply referred to as a circumferential groove.

More specifically, the block row 30, the block row 40, and the block row 50 are provided in the central land region CT1. The central land region CT1 may be defined as a region partitioned by a pair of circumferential main grooves 71 and a circumferential main groove 72 extending in the tire circumferential direction.

In the present embodiment, the central land region CT1 has a groove width similar to the groove width of the circumferential main groove 71 and the circumferential main groove 72 or wider than the groove width of the circumferential main groove 71 and the circumferential main groove 72. The circumferential groove having the above is not formed. In the present embodiment, the groove widths of the circumferential main groove 71 and the circumferential main groove 72 are about 4.0 to 10.0 mm, and the groove widths of the circumferential fine groove 61 and the circumferential fine groove 62 are about 1.5 to 4.0 mm. Is.

That is, only the circumferential groove extending in the tire circumferential direction, such as the circumferential groove 61 and the circumferential groove 62, is formed in the central land region CT1. Therefore, in the central land region CT1, the distance between adjacent land blocks (distance, which may be called a gap) is narrow in the tire width direction, and a plurality of land blocks are aggregated as compared with a general tire of this type. doing.

A plurality of land blocks 100 and 200 may be provided in the block row 30 along the tire circumferential direction. Specifically, a plurality of land blocks 100 are provided along the tire circumferential direction on one side in the tire width direction with respect to the tire equatorial line CL. A plurality of land blocks 200 are provided along the tire circumferential direction on the other side in the tire width direction with respect to the tire equatorial line CL. As shown in FIG. 1, the land block 100 and the land block 200 have substantially the same shape. Further, the land block 100 and the land block 200 may be point-symmetrical or line-symmetrical.

The block row 40 may be provided with a land block 101 having substantially the same shape as the land block 100 and a land block 201 having substantially the same shape as the land block 200. Further, the block row 50 may be provided with a land block 102 having substantially the same shape as the land block 100 and a land block 202 having substantially the same shape as the land block 200.

The rubber used for the land block constituting the tread 20, such as the land block 100 and the land block 200, may be appropriately made of an appropriate material in consideration of snow performance and wear resistance, and is not particularly limited. ..

However, a material that contributes to the reduction of rolling resistance (RR) of the pneumatic tire 10 may be used. Specifically, the rolling resistance coefficient (RRC) is preferably 7.5 or less.

(2) Shape of Block Row 30 FIG. 2 is a partially enlarged plan view of the block row 30. As shown in FIG. 2, the block row 30 is divided by a circumferential fine groove 61 extending in the tire circumferential direction and a circumferential fine groove 62.

The block row 30 has a plurality of land blocks 100 and land blocks 200 partitioned by widthwise grooves 300 extending in the tire width direction. That is, in the present embodiment, the block row 30 includes the land block 100 and the land block 200.

As described above, the circumferential narrow groove 61 and the circumferential fine groove 62 have a narrower groove width than the circumferential main groove 71 and the circumferential main groove 72. Further, in the present embodiment, the circumferential fine groove 61 and the circumferential fine groove 62 are linear. However, the circumferential narrow groove 61 and the circumferential fine groove 62 do not necessarily have to be linear, such as coasting slightly in the tire width direction.

A plurality of sipes extending in the tire width direction are formed in the land block 100 and the land block 200.

Specifically, a sipe 110 and a sipe 120 are formed on the land block 100. Further, a sipe 210 and a sipe 220 are formed on the land block 200. The sipe is a narrow groove that closes in the ground contact surface of the land block, and the opening width of the sipe when not in contact with the ground is not particularly limited, but is generally about 0.1 mm to 1.5 mm.

An inter-block groove 400 is formed between the land block 100 and the land block 200 in the tire width direction. The inter-block groove 400 extends along the tire circumferential direction, but coasts in the tire width direction rather than in a straight line.

The width direction groove 300 partitions the adjacent land block 100 in the tire circumferential direction and the adjacent land block 200 in the tire circumferential direction.

(3) Shape of Land Block Next, the shapes of the land block 100 and the land block 200 will be described with reference to FIGS. 2 and 3. FIG. 3 is a side view of the land block 100 from the F3 direction shown in FIG.

As shown in FIGS. 2 and 3, the land block 100 has three parts, specifically, a first end 130, a central 140 and a th sipe 120, which extend along the tire width direction. It is divided into two ends 150.

Similarly, the land block 200 is divided into three parts, specifically, a first end 230, a central 240 and a second end 250, by a sipe 210 and a sipe 220 extending along the tire width direction. To.

The first end portion 130 (first end portion 230) is located on one end side in the tire circumferential direction in the land portion block 100 (land portion block 200). The second end portion 150 (second end portion 250) is located on the other end side in the tire circumferential direction in the land portion block 100 (land portion block 200).

The central portion 140 (central portion 240) is located in the central portion in the tire circumferential direction in the land portion block 100 (land portion block 200).

On the surface of the land block 100 in contact with the road surface, that is, the surface of the tread 20 (see FIG. 1), a protrusion 160 that is convex toward the outside in the tire radial direction is provided. Similarly, a protrusion 260 is provided on the surface of the land block 200 in contact with the road surface.

As shown in FIG. 1, other land blocks, specifically, the land block 101, the land block 102, the land block 201, and the land block 202 are also provided with similar protrusions. You can.

In the present embodiment, the protrusion 160 and the protrusion 260 generally follow the normal line based on the diameter of the pneumatic tire 10, but the protrusion 160 and the protrusion 260 do not necessarily follow the normal line. It may also be slightly inclined in the tire width direction.

The protrusion 160 is preferably provided at least in the central portion 140 in the tread plane view. Similarly, the protrusion 260 is preferably provided at least in the central portion 240 in the tread plane view.

The protrusion 160 and the protrusion 260 may be integrally formed with the land block 100 (land block 200) in the manufacturing process (vulcanization step) of the pneumatic tire 10, that is, may be formed by tread rubber. Therefore, the protrusion 160 and the protrusion 260 are made of rubber.

The protrusion 160 (and the protrusion 260, the same applies hereinafter) may be formed as a separate body and may be fixed to the surface of the land block 100. In this case, the protrusion 160 may be made of a material harder than the rubber forming the land block 100, or a hard rubber, in order to further improve the performance on snow (here, in particular, the performance on ice). I do not care. However, considering traveling on a non-snowy road, it is preferable that the material can suppress damage to the paved road surface.

In the present embodiment, as shown in FIG. 3, the protrusion 160 (the protrusion 260 also has the same shape) has a tapered shape that tapers toward the outside in the radial direction of the tire. More specifically, the protrusion 160 has a conical shape. The diameter size of the protrusion 160 on the base end (surface of the land block 100) side is preferably about 0.8 mm or more and 3.0 mm or less in diameter.

However, the shape of the protrusion 160 does not have to be conical, and may be, for example, a quadrangular pyramid. Further, the shape of the protrusion 160 does not have to be tapered, and may be, for example, a columnar shape or a prismatic shape.

As described above, since at least the protrusion 160 is provided in the central portion 140 having a high ground pressure among the land block 100, the performance of the land block 100 scratching the ice-snow road surface (performance on ice) can be effectively improved.

Further, in the present embodiment, the protrusion 160 is also provided on the first end 130 and the second end 150. Further, in the present embodiment, the protrusion 160 is provided substantially at the center of the land block 100 in the tire width direction. Therefore, the performance on ice can be further improved.

(4) Modification example Next, a modification example of the block row 30 described above will be described. FIG. 4 is a partially enlarged plan view of the block row 30A according to the modified example. Hereinafter, the parts different from the block sequence 30 described above will be mainly described.

As shown in FIG. 4, in the block row 30A, the protrusion 160 is not substantially in the center of the land block 100 in the tire width direction in the tread plane view, but is located closer to the circumferential groove 61 in the land block 100. Provided. That is, the protrusion 160 is provided on the land block 100 at a portion closer to the end in the tire width direction.

Similarly, the protrusion 260 is provided not at substantially the center of the land block 200 in the tire width direction, but at a portion of the land block 200 closer to the circumferential groove 62. That is, the protrusion 260 is provided on the land block 200 at a portion closer to the end in the tire width direction.

The portion of the land block 100 near the circumferential groove 61 and the portion of the land block 200 near the circumferential groove 62 are portions where the ground pressure tends to be low (the ground pressure is easily released). By providing the protrusion 160 and the protrusion 260 in the portion, the performance of scratching the ice-snow road surface (performance on ice) of the land block 100 and the land block 200 as a whole can be effectively enhanced.

FIG. 5 is a partially enlarged plan view of the block row 30B according to another modified example. As shown in FIG. 5, in the block row 30B, the protrusion 160 is not substantially at the center of the first end 130 and the second end 150 in the tire circumferential direction, but is closer to the end of the land block 100 in the tire circumferential direction. It is provided in the part of.

Similarly, the protrusion 260 is provided not at substantially the center of the first end 230 and the second end 250 in the tire circumferential direction, but at a portion closer to the end of the land block 200 in the tire circumferential direction.

The portion of the land block 100 (land block 200) near the end in the tire circumferential direction is a portion that exerts an edge effect in the first place due to the end of the land block in the tire circumferential direction. By providing (protrusion part 260), a further edge effect can be brought out.

(5) Action / Effect As described above, according to the pneumatic tire 10, the surface of the land block 100 (land block 200) has a protrusion 160 (protrusion) that is convex toward the outside in the radial direction of the tire. 260) is provided.

For this reason, since it is partitioned by the circumferential groove 61 and the circumferential groove 62 having a narrow groove width, even if the ground pressure of the land block 100 (land block 200) tends to be low in the central land region CT1. , The protrusion 160 (protrusion 260) can effectively improve the ability to scratch the ice-snow road surface (snow performance or ice performance).

That is, even in the central land region CT1 where the ground pressure of the land block tends to be low, it is possible to avoid a decrease in the edge component that contributes to the performance of scratching the ice and snow road surface. Further, since the land block 100 and the land block 200 partitioned by the circumferential groove 61 and the circumferential groove 62 having a narrow groove width can support each other in the tire width direction, the land block 100 and the land block 200 and the land block 200 can be supported by each other. It is easy to maintain the rigidity of the land block 200, and wear resistance can be ensured.

That is, according to the pneumatic tire 10, while adopting a tread pattern in which the land blocks are aggregated in the central land region CT1, the running performance (snow performance or ice performance) on ice and snow road surface, particularly the driving performance on ice and snow road surface. (Snow traction) and braking performance can be compatible with wear resistance at a higher level.

In addition, the tread pattern in which the land blocks are aggregated in the central land region CT1 also contributes to the reduction of rolling resistance. That is, the tread pattern in which the land blocks are aggregated in the central land region CT1 contributes to the improvement of the running performance and the wear resistance of the icy and snowy road surface and the reduction of the rolling resistance.

Further, in the present embodiment, the protrusion 160 (protrusion 260) has a tapered shape that tapers toward the outside in the tire radial direction. Therefore, the protrusion 160 (protrusion 260) can easily bite into the ice / snow road surface, and further, the running performance of the ice / snow road surface can be improved.

(6) Other Embodiments Although the contents of the present invention have been described above according to the embodiments, the present invention is not limited to these descriptions, and various modifications and improvements are possible. It is self-evident to the trader.

For example, in the above-described embodiment, the land block 101, the land block 102, the land block 201, and the land block 202 are also provided with protrusions, but the protrusions are only the block row 30, that is, the tire. It may be provided only in the block row including the equatorial line CL or the land block.

Further, the protrusion may be a so-called spew formed along the vent for air bleeding formed in the manufacturing process (vulcanization process) of the pneumatic tire 10.

Further, in the above-described embodiment, the circumferential fine groove 61 and the circumferential fine groove 62 extending in the tire circumferential direction and the inter-block fine groove 400 are formed, but at least one or all of such fine grooves are formed. May not be formed. That is, the central land region CT1 does not have to have a groove component extending in the tire circumferential direction.

Although embodiments of the invention have been described above, the statements and drawings that form part of this disclosure should not be understood to limit the invention. Various alternative embodiments, examples and operational techniques will be apparent to those skilled in the art from this disclosure.

10 Pneumatic tires
20 tread
30, 30A, 30B, 40, 50 block rows
61, 62 Circumferential groove
71, 72 Circumferential main groove
100, 101, 102 Land block
110, 120 sipe
130 1st end
140 central part
150 2nd end
160 protrusions
200, 201, 202 Land block
210, 220 sipe
230 1st end
240 central part
250 2nd end
260 protrusions
300 width groove
400 block inter-groove
CL tire equatorial line
CT1 Central land area

Claims (5)

It has a central land area defined by a pair of circumferential grooves extending in the tire circumferential direction.
In the central land region, the groove width is narrower than the circumferential groove, and only the circumferential fine groove extending in the tire circumferential direction is formed, or the groove component extending in the tire circumferential direction is not formed, and the tire width direction A land block is provided, which is partitioned by a widthwise groove extending into the tire.
A tire provided with protrusions that are convex outward in the radial direction of the tire on the surface of the land block that is in contact with the road surface. The tire according to claim 1, wherein the protrusion is formed in a central portion of the land block in terms of tread. The tire according to claim 1, wherein the protrusion is formed closer to the end of the land block in the tire width direction in terms of tread. The tire according to claim 1, wherein the protrusion is formed near the end of the land block in the tire circumferential direction in terms of tread. The tire according to any one of claims 1 to 4, wherein the protrusion is tapered toward the outside in the radial direction of the tire.

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