JP2017210170A - Pneumatic tire - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a pneumatic tire which simultaneously satisfies enhancement in snow performance and enhancement in abrasion resistance.SOLUTION: A pneumatic tire comprises an asymmetric tread pattern. This tread pattern at least comprises: a pair of inner peripheral direction major grooves; a pair of outer peripheral direction major grooves; plural lug grooves which so traverse as to across two intermediate land parts and one center land part, which are formed from the inner peripheral direction major groove and the outer peripheral direction major groove, respectively; and plural sipes which are provided in an area of the intermediate land part and the center land part, and of which at least one end is communicated with the inner peripheral direction major groove and the outer peripheral direction major groove. A direction of inclination of each lug groove with respect to a tire width direction is opposite to that of inclination of the sipe with respect to the tire width direction.SELECTED DRAWING: Figure 2

Description

  The present invention relates to a pneumatic tire having a tread pattern.

  An all-season pneumatic tire (hereinafter referred to as an all-season tire) is a tire developed as an intermediate tire between a so-called “summer tire” used in a non-snow period and a snow tire called a winter tire. Widely used in North America and Europe. This all-season tire is required to have excellent maneuverability and braking / driving performance (snow performance) on snowy road surfaces and wear resistance performance on paved road surfaces. However, if the groove area is increased by providing grooves or sipes to improve snow performance, there is a problem that the block rigidity of the block elements provided in the tread pattern is lowered and the wear resistance is lowered.

On the other hand, there is known a pneumatic tire that reduces passing noise generated from the tire during acceleration traveling and improves uneven wear resistance (Patent Document 1).
The pneumatic tire is a pneumatic tire provided with a plurality of blocks defined by a plurality of circumferential grooves and lug grooves in a tread portion, and occupies up to 0.2 to 0.35 times the tread width. And the two end areas, the central area forms a non-directional flow pattern in which lug grooves are arranged at substantially point-symmetrical positions around a point on the tire equatorial plane, and is arranged in the central area. The stepped side surface of the block on the tire rotation direction side is inclined in the opposite direction to the tire equator plane with respect to the cord of the outermost belt ply arranged on the outermost side in the tire radial direction, and the block at the time of tire rolling is When the maximum angle formed by the ground contact surface contour line on the side to be depressed and the tire axial direction line is α, θ> α is satisfied in the central area.

JP 2002-19423 A

  However, although the pneumatic tire described above achieves a reduction in passing noise and an improvement in uneven wear resistance, it cannot satisfy the improvement of snow performance and the improvement of wear resistance at the same time.

  Then, an object of this invention is to provide the pneumatic tire which can satisfy the improvement of snow performance and the improvement of abrasion resistance simultaneously.

  One aspect of the present invention is a pneumatic tire including a tread pattern, and includes the following embodiments.

(Form 1)
The tread pattern of the pneumatic tire is an asymmetric pattern,
A pair of inner circumferential main grooves extending in the tire circumferential direction;
A pair of outer circumferential main grooves provided on the outer side in the tire width direction of the inner circumferential main grooves and extending in the tire circumferential direction;
Crossing each of the two intermediate land portions defined by the inner circumferential main groove and the outer circumferential main groove and the center land portion defined by the pair of inner circumferential main grooves, both ends are in the inner circumference. A plurality of lug grooves that divide the intermediate land portion and the center land portion into block elements by communicating with a direction main groove or the outer circumferential main groove;
A plurality of sipes provided in regions of the intermediate land portion and the center land portion, at least one end of which communicates with the inner circumferential main groove or the outer circumferential main groove;
Each of the lug grooves is inclined toward the first direction of the tire circumferential direction with respect to the tire width direction when going from the first side in the tire width direction to the second side,
All of the sipes are oriented in a second direction opposite to the first direction in the tire circumferential direction with respect to the tire width direction when going from the first side in the tire width direction to the second side. Pneumatic tire that tilts.

(Form 2)
One end of each sipe communicates with one of the inner circumferential main grooves or one of the outer circumferential main grooves, and the other end communicates with one of the lug grooves. The pneumatic tire according to 1.

(Form 3)
Of the two intermediate land portions, the first intermediate land portion located on the first side in the tire width direction includes, as the lug groove, two first bent portions in which the inclination angle of the extending groove changes. A first bent lug groove is provided,
The inclination angle of the groove with respect to the tire width direction of the first inner portion sandwiched between the two first bent portions of the first bent lug grooves is the two first bent lug grooves. The pneumatic tire according to the first or second aspect, which is larger than the first outer portion located outside the bent portion.

(Form 4)
The pneumatic tire according to mode 3, wherein one of the sipes is connected to each of the two first bent portions.

(Form 5)
The pneumatic tire according to aspect 3 or 4, wherein the first bent lug groove and the non-bent lug groove not having the first bent portion are alternately provided in the tire circumferential direction.

(Form 6)
The edge length along the inner circumferential main groove of the two block elements sandwiching the first bent lug groove from both sides in the tire circumferential direction is different,
Of the first bent lug groove, the groove depth of the portion between the open end communicating with one of the inner circumferential main grooves and one of the first bent portions located on the first side is The pneumatic tire according to any one of Embodiments 3 to 5, which is shallower than the groove depth of a portion other than the portion.

(Form 7)
Among the first bent lug grooves, one groove wall surface between one of the first bent portions located on the first side and an open end communicating with one of the outer circumferential main grooves is The pneumatic according to any one of aspects 3 to 6, wherein an inclined chamfer is provided so that the groove wall is inclined so that the groove width increases as it approaches the opening end communicating with one of the outer circumferential main grooves. tire.

(Form 8)
The first bent lug groove is provided in the tire circumferential direction alternately with the non-bent lug groove not having the first bent portion, and the block element in which the inclined chamfer is provided among the block elements of the first intermediate land portion. The groove wall surface of the non-bending lug groove that is in contact with the groove is provided with an inclined chamfer that the groove wall is inclined so that the groove width is widened toward the opening end that communicates with one of the outer circumferential main grooves. 7. The pneumatic tire according to 7.

(Form 9)
Among the lug grooves, the second lug groove provided in the second intermediate land portion located on the second side with respect to the center land portion is a non-bent lug groove that does not have the first bent portion. The pneumatic tire according to any one of forms 3 to 8.

(Form 10)
The center land portion is provided with a second bent lug groove having two second bent portions in which the inclination angle of the extending groove changes as the lug groove,
The inclination angle of the groove with respect to the tire width direction of the second inner portion sandwiched between the two second bent portions of the second bent lug grooves is the second second of the second bent lug grooves. The pneumatic tire according to any one of Embodiments 1 to 9, which is larger than the second outer portion located outside the bent portion.

(Form 11)
The pneumatic tire according to mode 10, wherein one of the sipe is connected to each of the two second bent portions.

(Form 12)
The pneumatic tire according to aspect 10 or 11, wherein the second bent lug groove is provided alternately in the tire circumferential direction with a non-bent lug groove that does not have the second bent portion.

(Form 13)
Of the second bent lug groove, an opening end communicating with the inner circumferential main groove located on the second side of the inner circumferential main groove and the first bent portion located on the first side. The pneumatic tire according to any one of Embodiments 10 to 12, wherein the groove depth between the portions is shallower than the groove depths of the other portions.

(Form 14)
Of the second bent lug grooves, one of the second bent portions located on the first side and an opening communicating with the inner circumferential main groove located on the first side of the inner circumferential main grooves. One groove wall surface between the ends is provided with an inclined chamfer in which the groove wall is inclined so that the groove width is widened toward the opening end communicating with the inner circumferential main groove located on the first side. The pneumatic tire according to any one of forms 10 to 13.

(Form 15)
The second bent lug groove is provided in the tire circumferential direction alternately with the non-bent lug groove not having the second bent portion, and is in contact with the block element provided with the inclined chamfer among the block elements of the center land portion. The groove wall surface of the non-bent lug groove is provided with an inclined chamfering that the groove wall is inclined so that the groove width is widened toward the opening end communicating with the inner circumferential main groove located on the first side. The pneumatic tire according to claim 14.

(Form 16)
Among the lug grooves, the tire circumferential direction of the opening end that communicates with the inner circumferential main groove of the first lug groove provided in the first intermediate land portion located on the first side with respect to the center land portion. Of the lug grooves, the center of the lug groove, and the center of the extended portion that extends by extending one of the center lug grooves provided in the center land portion to the first side is the center lug portion of the first intermediate land portion. Forms 1 to 15 in which the separation distance between the position in the tire width direction of the edge on the second side and the virtual position that intersects is 20% or less of the tire circumferential direction length of the block element in the first intermediate land portion. A pneumatic tire according to any one of the above.

(Form 17)
A plurality of linear micro grooves having a groove depth shallower than the groove depth of the lug groove and narrower than the groove width of the lug groove extend in parallel with each other on the tread surface in contact with the ground of the center land portion. The pneumatic tire according to any one of aspects 1 to 16, wherein a microgroove region is provided.

(Form 18)
The block element of the center land portion includes a micro-grooved block element in which the micro-groove region is provided on the entire surface, and a smooth block element in which the micro-groove is not provided and a smooth surface is provided on the entire surface,
The pneumatic tire according to claim 17, wherein the block elements with microgrooves and the smooth block elements are provided alternately in the tire circumferential direction.

(Form 19)
Of the intermediate land portion, the tread surface in contact with the ground of the first intermediate land portion located on the first side with respect to the center land portion has a groove depth shallower than the groove depth of the lug groove, A plurality of linear microgrooves whose groove width is narrower than the groove width of the lug grooves are provided with microgroove regions extending in parallel with each other,
The block element of the first intermediate land portion includes: a block element with a microgroove in which the microgroove region is provided on the entire surface; and a smooth block element in which the microgroove is not provided and a smooth surface is provided on the entire surface. Including
In the first intermediate land portion, the block elements with microgrooves and the smooth block elements are alternately provided in the tire circumferential direction,
The block element with the microgroove of the center land portion and the block element of the first intermediate land portion with edges facing each other through one of the inner circumferential main grooves are smooth block elements,
The block element with the microgroove in the first intermediate land portion and the block element in the center land portion, the edges of which are opposed to each other through one of the inner circumferential main grooves, are smooth block elements. Pneumatic tires.

(Form 20)
Of the intermediate land portion, the tread surface in contact with the ground of the first intermediate land portion located on the first side with respect to the center land portion has a groove depth shallower than the groove depth of the lug groove, The pneumatic tire according to any one of Embodiments 1 to 16, wherein a plurality of linear microgrooves whose groove width is narrower than the groove width of the lug grooves are provided with microgroove regions extending in parallel with each other.

(Form 21)
The block element of the intermediate land portion includes a block element with a microgroove in which the microgroove region is provided on the entire surface, and a smooth block element in which the microgroove is not provided and a smooth surface is formed,
The pneumatic tire according to aspect 20, wherein the block elements with microgrooves and the smooth block elements are provided alternately in the tire circumferential direction.

(Form 22)
A shoulder land portion is provided on the outer side in the tire width direction of each of the outer circumferential main grooves, and a shoulder lug groove extending in the tire width direction is provided in each region of the shoulder land portion. Also, any one of the embodiments 1 to 21 that, when going from the first side in the tire width direction to the second side, is inclined toward the second direction in the tire circumferential direction with respect to the tire width direction. The pneumatic tire according to one.

  According to the pneumatic tire described above, it is possible to satisfy the improvement of snow performance and the improvement of wear resistance at the same time.

It is profile sectional drawing of an example of the tire of this embodiment. It is a figure explaining an example of the tread pattern of the tire of this embodiment. (A) is a figure explaining the block element formed in the intermediate land part shown in FIG. 2, (b) is sectional drawing of the block element along the XX 'line in Fig.3 (a). It is. (A) is a figure explaining an example of the block element of the center land part of the tread pattern of this embodiment, (b) is an example of the block element of the 2nd intermediate land part of the tread pattern of this embodiment. It is a figure explaining. It is a figure explaining a part of tread pattern of a prior art example.

Hereinafter, the pneumatic tire of the present invention will be described in detail with reference to the accompanying drawings.
The pneumatic tire of this embodiment described below is applied to, for example, an all-season tire for passenger cars, but can also be applied to an all-season tire for light trucks or an all-season tire for buses and trucks. The pneumatic tire of this embodiment described below is an all-season tire for passenger cars.

  In the following description, the tire width direction is a direction parallel to the rotation axis of the pneumatic tire. The outer side in the tire width direction is the side away from the tire center line CL representing the tire equatorial plane with respect to the position to be compared in the tire width direction. The inner side in the tire width direction is the side closer to the tire center line CL in the tire width direction with respect to the position to be compared. The tire circumferential direction is a direction in which the pneumatic tire rotates around the rotation axis of the pneumatic tire. The tire circumferential direction includes a first direction and a second direction that are different from each other. The tire radial direction is a direction orthogonal to the rotation axis of the pneumatic tire. The outer side in the tire radial direction refers to the side away from the rotation axis along the tire radial direction with respect to the position to be compared. Further, the inner side in the tire radial direction refers to a side closer to the rotation axis along the tire radial direction with respect to the position to be compared.

(Tire structure)
FIG. 1 shows a profile cross-sectional view of an example of a tire 10 of the present embodiment. The tire 10 includes a tread portion 10T having a tread pattern, a pair of bead portions 10B, and a pair of bead portions 10B and a pair of side portions 10S that are connected to the tread portion 10T. Prepare.
The tire 10 includes a carcass ply layer 12, a belt layer 14, and a bead core 16 as a skeleton material. Around these skeleton materials, a tread rubber member 18, a side rubber member 20, and a bead filler rubber member 22. And a rim cushion rubber member 24 and an inner liner rubber member 26.

  The carcass ply layer 12 is made of a carcass ply material in which organic fibers are covered with rubber, which is wound between a pair of annular bead cores 16 to form a toroidal shape. The carcass ply material is wound around the bead core 16 and extends outward in the tire radial direction. A belt layer 14 composed of two belt members 14a and 14b is provided outside the carcass ply layer 12 in the tire radial direction. The belt layer 14 is a member in which rubber is coated on a steel cord disposed at a predetermined angle, for example, 20 to 30 degrees with respect to the tire circumferential direction, and the lower belt material 14a is formed on the upper belt material 14b. The width in the tire width direction is wider than that. The inclination directions of the steel cords of the two-layer belt materials 14a and 14b are opposite to each other. For this reason, belt material 14a, 14b is a crossing layer, and controls expansion of carcass ply layer 12 by the filled air pressure.

A tread rubber member 18 is provided on the outer side of the belt layer 14 in the tire radial direction, and side rubber members 20 are connected to both ends of the tread rubber member 18 to form a side portion 10S. A rim cushion rubber member 24 is provided at the inner end in the tire radial direction of the side rubber member 20 and is in contact with a rim on which the tire 10 is mounted. The bead core 16 is sandwiched between the portion of the carcass ply layer 12 before being wound around the bead core 16 and the portion of the carcass ply layer 12 that is wound around the bead core 16 on the outer side in the tire radial direction. Thus, a bead filler rubber member 22 is provided. An inner liner rubber member 26 is provided on the inner surface of the tire 10 facing the tire cavity region filled with air surrounded by the tire 10 and the rim.
In addition, the tire 10 may include a bead reinforcing material between the carcass layer 12 wound around the bead core 16 and the bead filler rubber member 22. Furthermore, a two-layer belt cover layer 30 that covers the belt layer 14 from the outer side in the tire radial direction of the belt layer 14 and is coated with an organic fiber or a steel cord with rubber may be provided. The tire structure of the present embodiment is as described above, but the tire structure is not particularly limited, and a known tire structure can be applied. In FIG. 1, inner circumferential main grooves 42a and 42b and outer circumferential main grooves 44a and 44b, which will be described later, are shown. However, center lug grooves 46 and 47, and intermediate lug grooves 50a, 50b, and 51a, which will be described later. The shoulder lug grooves 54a and 54b and the sipes 56a, 56b and 56c are not shown.

(Tread pattern)
FIG. 2 is a diagram illustrating an example of a tread pattern according to the present embodiment. In FIG. 2, the vertical direction of the paper surface corresponds to the tire circumferential direction, and the horizontal direction of the paper surface corresponds to the tire width direction. With respect to the tire circumferential direction, in FIG. 2, the downward direction on the paper is referred to as a first direction, and the upward direction on the paper is referred to as a second direction. Regarding the tire width direction, in FIG. 2, the right side of the drawing is referred to as the first side and the left side of the drawing is referred to as the second side with respect to the tire center line CL.

The tread pattern 40 shown in FIG. 2 is not a line-symmetric pattern or a point-symmetric pattern, but an asymmetric pattern. The tread pattern 40 includes a pair of inner circumferential main grooves 42a, 42b, a pair of outer circumferential main grooves 44a, 44b, center lug grooves 46, 47, intermediate lug grooves 50a, 50b, 51a, and shoulder lug grooves. 54a, 54b and sipes 56a, 56b, 6c. The tread pattern 40 includes four circumferential main grooves, but is not limited to the four circumferential main grooves, and may include five, six or more circumferential main grooves. In this case, it is preferable that the circumferential main grooves are provided outside the outer circumferential main grooves 44a and 44b in the tire width direction.
The tread pattern 40 has an asymmetric pattern formed by the shape and inclination direction of the intermediate lug grooves 50a, 50b, and 51a and the inclination direction of the sipes 56a, 56b, and 56c.

  The inner main direction main grooves 42a and 42b are grooves that extend linearly in the tire circumferential direction, and the tire represents the center in the width direction of the tire 10 between the inner circumferential main groove 42a and the inner circumferential main groove 42b. Center line CL passes. Accordingly, half tread regions are provided on both sides (first side and second side) in the tire width direction with the tire center line CL as the center. The half-tread area on the right side (first side) in FIG. 2 is called a half-tread area A, and the half-tread area on the left side (second side) in FIG. Accordingly, in the half tread region A, the inner circumferential main groove 42a, the outer circumferential main groove 44a, the intermediate lug grooves 50a and 51a, the shoulder lug groove 54a, and the sipe 56a are mainly provided. On the other hand, in the half tread region B, an inner circumferential main groove 42b, an outer circumferential main groove 44b, an intermediate lug groove 50b, a shoulder lug groove 54b, and a sipe 56b are mainly provided. When the tire 10 is mounted on the vehicle, the tire 10 is set to be mounted on the vehicle so that the first side of the half-tread region A of the tire 10 faces the outside of the vehicle. The vehicle mounting information is preferably displayed on the surface of the side portion 10S of the tire 10 as mounting instruction information.

The outer circumferential main grooves 44a and 44b are grooves that extend linearly in the tire circumferential direction, and are provided on the outer side in the tire width direction with respect to the inner circumferential main grooves 42a and 42b.
The inner circumferential main grooves 42a and 42b and the outer circumferential main grooves 44a and 44b all extend linearly in the tire circumferential direction, but are not necessarily grooves that extend linearly. Instead of the linearly extending groove, for example, a zigzag groove extending in the tire circumferential direction while meandering or bending in the tire width direction may be used.
The groove widths of the inner circumferential main grooves 42a and 42b and the outer circumferential main grooves 44a and 44b are, for example, 3 to 18 mm, and the groove depth is, for example, 5 to 12 mm.

A center land portion 60 is provided between the inner circumferential main groove 42a and the inner circumferential main groove 42b. In the region of the center land portion 60, a plurality of center lug grooves 46, 47 are alternately provided at intervals in the tire circumferential direction. Both ends of the center lug grooves 46 and 47 communicate with the inner circumferential main grooves 42a and 42b, thereby dividing the center land portion 60 into block elements.
A sipe 56c is provided in the region of the center land portion 60. One end of the sipe 56c communicates with the inner circumferential main groove 42a or the inner circumferential main groove 42b. In a preferred form of the present embodiment, the other end of the sipe 56 c communicates (connects) with the center lug groove 46 or the center lug groove 47.
The center lug grooves 46 and 47 are inclined toward the first direction in the tire circumferential direction with respect to the tire width direction when going from the first side in the tire width direction to the second side.

  The groove width of the center lug grooves 46 and 47 is, for example, 2 to 10 mm, and the groove depth is, for example, 2 to 10 mm. The width of the sipe 56c is, for example, 0.5 to 2 mm, and the depth is, for example, 2 to 10 mm. The width of the sipe 56c is preferably 0.5 to 1 mm, and the depth is preferably 3 to 7 mm.

In the region of the intermediate land portion (first intermediate land portion) 62a between the inner circumferential main groove 42a and the outer circumferential main groove 44a in the half tread region A, the intermediate lug grooves 50a and 51a are spaced apart in the tire circumferential direction. There are a plurality of open spaces. Further, a sipe 56a is provided in the region of the intermediate land portion 62a.
The intermediate lug grooves 50a and 51a are both in communication with the inner circumferential main groove 42a and the outer circumferential main groove 44a, and both ends of the intermediate lug grooves 50a and 51a are both in the inner circumferential main groove 42a and the outer circumferential main groove 44a. It is the opening end opened to the groove 44a. Therefore, a plurality of block land portions that are partitioned in the tire circumferential direction by the intermediate lug grooves 50a and 51a are formed in the region of the intermediate land portion 62a.
Similar to the center lug grooves 46 and 47, the intermediate lug grooves 50a and 51a have a first direction in the tire circumferential direction with respect to the tire width direction when heading from the first side in the tire width direction to the second side. Inclined towards
The groove width of the intermediate lug grooves 50a and 51a is, for example, 2 to 10 mm, and the groove depth is, for example, 2 to 10 mm.

One end of the sipe 56a communicates with the inner circumferential main groove 42a or the outer circumferential main groove 44a. In the preferred form of this embodiment, the other end of the sipe 56a communicates (connects) with the intermediate lug groove 50a or the intermediate lug groove 51a.
The width of the sipe 56a is, for example, 0.5 to 2 mm, and the depth is, for example, 2 to 10 mm. The width of the sipe 56a is preferably 0.5 to 1 mm, and the depth is preferably 3 to 7 mm.

In the region of the intermediate land portion (second intermediate land portion) 62b between the inner circumferential main groove 42b and the outer circumferential main groove 44b in the half tread region B, the intermediate lug groove 50b is spaced apart in the tire circumferential direction. A plurality are provided. Each of the intermediate lug grooves 50b communicates with the inner circumferential main groove 42b and the outer circumferential main groove 44b. Accordingly, a plurality of block land portions that are partitioned in the tire circumferential direction by the intermediate lug grooves 50b are formed in the region of the intermediate land portion 62b. Similar to the intermediate lug grooves 50a and 51a and the center lug grooves 46 and 47, the intermediate lug groove 50b extends in the tire circumferential direction with respect to the tire width direction when going from the first side in the tire width direction to the second side. Of these, it is inclined toward the first direction.
The groove width of the intermediate lug groove 50b is, for example, 2 to 10 mm, and the groove depth is, for example, 2 to 10 mm.

One end of the sipe 56b communicates with the inner circumferential main groove 42b or the outer circumferential main groove 44b. In a preferred form of this embodiment, the other end of the sipe 56b communicates (connects) with the intermediate lug groove 50b.
Furthermore, the width of the sipe 56b is, for example, 0.5 to 2 mm, and the depth is, for example, 2 to 10 mm. The width of the sipe 56b is preferably 0.5 to 1 mm, and the depth is preferably 3 to 7 mm.
The sipes 56a, 56b, and 56c are inclined toward the second direction in the tire circumferential direction with respect to the tire width direction when going from the first side in the tire width direction to the second side. That is, the inclination direction of the sipes 56a, 56b, and 56c with respect to the tire width direction is opposite to the inclination direction of the center lug grooves 46 and 47 and the intermediate lug grooves 50a, 50b, and 51a with respect to the tire width direction.

A plurality of shoulder lug grooves 54a and 55a are provided at intervals in the tire circumferential direction in the region of the shoulder land portion 64a on the outer side in the tire width direction of the outer circumferential main groove 44a in the half tread region A. A shoulder lug groove 55a is provided in a region between two shoulder lug grooves 54a adjacent to each other in the tire circumferential direction among the plurality of shoulder lug grooves 54a.
Further, a plurality of shoulder lug grooves 54b are provided in the tire circumferential direction at intervals in the region of the shoulder land portion 64b on the outer side in the tire width direction of the outer circumferential main groove 44b in the half tread region B. A sipe 55b is provided in a region between two shoulder lug grooves 54b adjacent in the tire circumferential direction among the plurality of shoulder lug grooves 54b. The shoulder lug grooves 54a and 54b are the second direction of the tire circumferential direction with respect to the tire width direction when the tire lug grooves 54a and 54b are directed from the first side in the tire width direction to the second side in the same manner as the sipes 56a, 56b, and 56c. Inclined towards
One end of each of the shoulder lug grooves 54a and 55a is closed without communicating with the outer circumferential main groove 44a. Shoulder lug grooves 54a, 55a extend from the closed to end up pattern end E _A toward the outer side in the tire width direction. One end of the shoulder lug groove 54b communicates with the outer circumferential main groove 44b. Shoulder lug grooves 54b extend to the pattern end E _B from the open end toward the outer side in the tire width direction.
The shoulder lug grooves 54a, 54b, and 55a have a groove width of, for example, 2 to 10 mm, and a groove depth of, for example, 2 to 10 mm.

As described above, in the tread pattern 40, the lug grooves provided in the regions of the center land portion 60 and the intermediate land portions 62a and 62b, that is, the tires of the center lug grooves 46 and 47, the intermediate lug grooves 50a and 51a, and the intermediate lug groove 50b. By aligning the direction of inclination with respect to the width direction in one direction, the block element formed by the lug groove is formed between the lug groove and the inner circumferential main grooves 42a, 42b or the outer circumferential main grooves 44a, 44b. The sharp-angled region R (see FIG. 2) having a low block rigidity is unevenly distributed to one side in each land portion, so that it is difficult to become a core of wear. When the direction of the inclination of the lug groove with respect to the tire width direction is different across the inner circumferential main groove or the outer circumferential main groove, the acute-angled region R having low block rigidity is the inner circumferential main groove or the outer circumferential direction. Since it concentrates on the side in contact with the main groove, it tends to become the core of wear.
On the other hand, by aligning the direction of the inclination of the center lug grooves 46, 47, the intermediate lug grooves 50a, 51a, and the intermediate lug grooves 50b with respect to the tire width direction in one direction, the block rigidity of the block elements is made anisotropic. When the block element is in contact with the ground, a rotational component is generated in the block element so as to make a slip angle on the tire, and a force that causes a vehicle flow is easily generated. For this reason, in the present embodiment, the sipe 56a, 56b, 56c, and further the shoulder lug groove 54a, in order to suppress the force that causes the vehicle flow by generating a rotational component that cancels the rotational component. The inclination direction with respect to the tire width direction of 54b is defined. That is, the inclination direction is opposite to the inclination direction of the lug grooves of the center lug grooves 46 and 47, the intermediate lug grooves 50a and 51a, and the intermediate lug groove 50b with respect to the tire width direction.
Further, the inclination direction of the sipe 56a, 56b, 56c with respect to the tire width direction is opposite to the inclination direction of the center lug grooves 46, 47, the intermediate lug grooves 50a, 51a, and the intermediate lug groove 50b with respect to the tire width direction. Therefore, snow characteristics are improved. Small piece elements in the block elements delimited by the sipes 56a, 56b, and 56c have anisotropy of block rigidity different from that of the center lug grooves 46 and 47, the intermediate lug grooves 50a and 51a, and the intermediate lug groove 50b. For this reason, when an anisotropic block element comes into contact with the ground to generate a rotation component and tries to deform, the small piece element in the block element delimited by the sipes 56a, 56b, and 56c has the above rotation component. A rotational component that cancels out is generated, and the small element is locally deformed by the rotational component that cancels out. Due to this deformation, the inner circumferential main grooves 42a and 42b, the outer circumferential main grooves 44a and 44b, the center lug grooves 46 and 47, the intermediate lug grooves 50a and 51a, and the wall surfaces of the intermediate lug grooves 50b are uneven. This unevenness will harden the snow that has entered the groove. For this reason, the snow property is improved by the snow column shearing force of the pressed snow.

  As shown in FIG. 2, one end of each of the sipes 56a, 56b, 56c communicates with one of the inner circumferential main grooves 42a, 42b or one of the outer circumferential main grooves 44a, 44b, and the other end. Is preferably communicated with one of the center lug grooves 46, 47 and the intermediate lug grooves 50a, 50b, 51a. As a result, the block stiffness distribution of the block elements can be made closer to uniform, the generation of wear nuclei can be suppressed, and the edge component effective for snowiness can be increased.

As shown in FIG. 3A, the intermediate lug groove 51a provided in the region of the intermediate land portion 62a located on the first side has two bent portions 51a _{1 in which} the inclination angle of the extending groove changes. 51a ₂ , and the inclination angle of the groove with respect to the tire width direction of the inner portion 51a ₃ sandwiched between the _two bent portions 51a ₁ , 51a ₂ of the bent lug groove is determined by the bent lug. It is preferable that the groove is larger than the outer portion located outside the _two bent portions 51a ₁ and 51a ₂ . Thereby, since the length along the groove | channel direction of the intermediate | middle lug groove 51a can be lengthened, the edge component effective for snow property can be increased, and snow property can be improved. FIG. 3A is a diagram for explaining block elements formed in the intermediate land portion 62a shown in FIG.
At this time, as shown in FIG. 3 (a), the bent portion _51a 1, 51a ₂ is preferably sipe 56a is connected.
Further, as shown in FIG. 2, in the region of the intermediate land portion 62a, intermediate lug grooves 51a having bent portions 51a ₁ and 51a ₂ and intermediate lug grooves 50a that are non-bent lug grooves having no bent portions are alternately arranged. Are preferably provided in the tire circumferential direction.

As shown in FIG. 3A, the edge length along the inner circumferential main groove 42a of the two block land portions sandwiching the bent lug groove (intermediate lug groove 51a) from both sides in the tire circumferential direction (FIG. 3A The edge lengths L ₁ and L ₂ ) of the _two block elements are different, and of the first bent lug grooves, the bent portions 51a ₁ are located on the first side and the open end communicating with the inner circumferential main groove 42a. the groove depth of the portion between the shallow compared to the groove depth of the other portion (portion between the open end of the bent lug grooves are open to the outside circumferential main groove 44a and the bent portion 51a ₁₎ It is preferable. Of the intermediate land portion 62a, the block element having a short edge length (the block element having the edge length L2 in FIG. 3A) has a constant groove depth of the bent lug groove (intermediate lug groove 51a). In this case, the block rigidity is lower than that of the other block elements, and the amount of the decrease is large. However, a decrease in block rigidity of the block land portion, as described above, the groove depth of the portion between the opening end and the bent portion 51a ₁ located on a first side of which communicates with the inner circumferential main groove 42a It can be suppressed by shallowing. For this reason, the block land portion having a short edge length is unlikely to become a core of wear.

As shown in FIG. 3 (a), of bending the lug groove (intermediate lug grooves 51a), the open end communicating with one of the bent portions 51a ₁ and the outer circumferential main groove 44a located on the first side of on one of the groove walls during, preferably inclined chamfer 51a ₄ of the groove wall so that the groove width closer to the open end communicating with one of the outer circumferential main groove 44a extends is inclined is provided. By providing an inclined chamfer 51a _4, takes in much snow by bending the lug groove (intermediate lug grooves 51a), it is possible to generate snow pillar shearing force to harden snow, snow resistance is improved.
At this time, as shown in FIG. 2, the bent lug groove (intermediate lug groove 51a) is provided alternately in the tire circumferential direction with the non-bent lug groove (intermediate lug groove 50a) having no bent portion, and the intermediate land portion 62a. Among the block elements, the groove wall surface of the non-bent lug groove (intermediate lug groove 50a) in contact with the block element provided with the inclined chamfer 51a ₄ (of the block element, the portion provided with the inclined chamfer 51a ₄ and the tire circumference) As shown in FIG. 3 (a), the groove wall inclines so that the groove width increases toward the opening end communicating with the outer circumferential main groove 44a. An inclined chamfer 50a ₁ is preferably provided.

  Furthermore, the intermediate lug groove 50b provided in the region of the intermediate land portion 62b located on the second side with respect to the center land portion 60 is a non-bent lug groove having no bent portion, as shown in FIG. It is preferable.

As shown in FIG. 4A, the center land portion 60 is provided with a bent lug groove (intermediate lug groove 46) having _two bent portions 46c ₁ and 46c _{2 in} which the inclination angle of the extending groove changes. ing. The inclination angle of the groove with respect to the tire width direction of the inner portion sandwiched between the _two bent portions 46c ₁ and 46c ₂ of the bent lug groove (intermediate lug groove 46) is the bent lug groove (intermediate lug groove 46). Of these, it is preferable that the edge portion of the bent lug groove (intermediate lug groove 46) is longer than that of the outer portion located outside the two second bent portions 46c ₁ and 46c ₂ .
At this time, as shown in FIG. 4A, a sipe 56c is preferably connected to each of the _two bent portions 46c ₁ and 46c ₂ . FIG. 4A is a diagram illustrating block elements of the center land portion 60 of the block pattern shown in FIG.
Further, in the region of the center land portion 60, the bent lug groove (intermediate lug groove 46) is preferably provided alternately in the tire circumferential direction with the non-bent lug groove (intermediate lug groove 47) having no bent portion. .
Of the bent lug grooves provided in the region of the center land portion 60 (center lug grooves 46), the portion between the bent portions 46c ₂ which is positioned at the opening end and the first side of which communicates with the inner circumferential main grooves 42b It is preferable that the groove depth is shallower than the groove depth of the other portions.
Of the bent lug grooves (intermediate lug grooves 46), on one groove wall surface between the open end communicating with the bent portion 46c ₂ and the inner circumferential main groove 42a located on a first side, Fig. 4 (a as shown in), closer to the open end that communicates with the inner circumferential main groove 42a, the inclined chamfered 46c ₃ which groove wall as the groove width is widened to tilt is provided, it is preferable.

In the region of the center land portion 60, the bent lug groove (intermediate lug groove 46) is preferably provided alternately in the tire circumferential direction together with the non-bent lug groove (intermediate lug groove 47) having no bent portion. At this time, among the block elements of the center land portion 60, of the groove wall surface (the block elements on the non-bending lug groove adjacent to the block element is inclined chamfer 46c ₃ provided (intermediate lug groove 47), it is provided inclined chamfer 46c ₃ The chamfer 46c in which the groove wall is inclined so that the groove width is wider toward the opening end communicating with the inner circumferential main groove 42a. ₄ is preferably provided.

  The center position in the tire circumferential direction of the opening end that communicates with the inner circumferential main groove 42a of the intermediate lug grooves 50a and 51a, and an extension portion that extends by extending one of the center lug grooves 46 and 47 to the first side. The separation distance between the center and the virtual position where the edge of the second side edge of the intermediate land portion 62a intersects the position in the tire width direction is 20% or less of the tire circumferential length of the block element in the intermediate land portion 42a. Preferably there is.

  As shown in FIGS. 3A and 3B, on the tread surface of the block element in contact with the ground of the intermediate land portion 62a, the groove depth is shallower than the groove depths of the intermediate lug grooves 50a and 51a. , 51a, it is preferable that a plurality of linear micro grooves 70 whose groove width is narrower than the groove width are provided with micro groove regions extending in parallel with each other. FIG. 3B is a cross-sectional view of the block element taken along line X-X ′ in FIG. The groove depth of the microgroove 70 is, for example, 0.2 to 2 mm, preferably 0.3 to 0.5 mm, and the groove width is, for example, 0.2 to 2 mm, preferably 0.5 to 1 mm. The microgrooves 70 are provided at intervals of, for example, 1 to 2 mm or 0.8 to 1.6 mm, preferably 1 to 1.2 mm. In addition, the said space | interval may be constant and does not need to be constant. The microgroove 70 extends linearly, but may extend in a curved shape. The extending direction of the microgroove 70 is preferably an inclination direction in a range of −60 degrees to +60 degrees with respect to the tire circumferential direction.

As shown in FIG. 4A, on the tread surface in contact with the ground of the center land portion 60, the groove depth is shallower than the groove depth of the center lug grooves 46 and 47, and the groove depth is larger than the groove width of the center lug grooves 46 and 47. It is preferable that a plurality of linear microgrooves 70 having a narrow width are provided with microgroove regions extending in parallel with each other. The groove depth of the micro groove 70 in the center land portion 60 is also, for example, 0.2 to 2 mm, preferably 0.3 to 0.5 mm, and the groove width is also, for example, 0.2 to 2 mm, preferably 0.5-1 mm. The microgrooves 70 are provided, for example, at an interval of 0.8 to 1.6 mm, preferably at an interval of 1 to 1.2 mm. In addition, the said space | interval may be constant and does not need to be constant. The microgroove 70 extends linearly, but may extend in a curved shape. The extending direction of the microgroove 70 is preferably an inclination direction in a range of −60 degrees to +60 degrees with respect to the tire circumferential direction.
Such a microgroove region is preferably provided on the entire surface of the block element in contact with the ground formed by the intermediate lug grooves 50a and 51a and the center lug grooves 46 and 47. By providing the micro groove area in the middle land portion 60a and the center land portion 60, the edge component increases, so that the grip on the road surface on snow is improved and the snow property is improved.

  As shown in FIG. 2, the block element of the center land portion 60 is a block element with a micro groove (gray area in FIG. 2) in which the micro groove area is provided on the entire surface in contact with the ground, and the micro groove is not provided. A smooth block element (white area in FIG. 2) provided on the entire surface of the block element in which the smooth surface is in contact with the ground, and the micro-grooved block element and the smooth block element are provided alternately in the tire circumferential direction. It is preferable that Thereby, the visibility of the shape of the block element of the center land portion 60 is improved, and the tread pattern can be easily identified.

  A block element with a microgroove provided with a microgroove region on the entire surface of the block element of the intermediate land portion 62a in contact with the ground, and a smooth surface provided on the entire surface of the block element in contact with the ground without a microgroove. In the intermediate land portion 62a, the micro-grooved block elements and the smooth block elements are alternately provided in the tire circumferential direction to improve the visibility of the shape of the block elements. The tread pattern can be easily identified, which is preferable. At this time, the block element with the micro groove of the center land portion 60 and the block element of the intermediate land portion 62a whose edges face each other via the inner circumferential main groove 42a are smooth block elements, and the micro elements of the intermediate land portion 62a. From the point that the block element of the center land portion 60 whose edge is opposed to the grooved block element and the inner circumferential main groove 42a is a smooth block element can easily identify the tread pattern. preferable.

FIG. 4B is a diagram illustrating block elements of the intermediate land portion 62b. As shown in FIG. 4 (b), one groove wall surface of the intermediate lug groove 50b has an inclined chamfer 50b in which the groove wall is inclined so that the groove width is widened toward the opening end communicating with the outer circumferential main groove 44b. ₁ is preferably provided. Moreover, as shown in FIG.4 (b), the narrow groove | channel 72 which both ends closed inside the block element may be provided in the block element of the intermediate land part 62b.

(Examples, comparative examples, conventional examples)
In order to confirm the effect of the present embodiment, a tire 10 having the tire structure shown in FIG. 1 (tire size: 275 / 45R20) is manufactured, rim-assembled into a rim 20 × 8.5 JJ, and 250 kPa air is filled into the tire. did. This tire was mounted on a SUV (Sport Utility Vehicle) vehicle as a test vehicle, and durability and snowiness were evaluated.
In terms of durability, the test vehicle is run for 20,000 km on the set course, the mileage for which the test vehicle is completely worn is determined from the amount of wear at that time, and the wear resistance is indexed by the reciprocal of the obtained mileage. did. The index of wear resistance means that the index of a conventional example, which will be described later, is 100, and the higher the index, the better the wear resistance.
Snowiness was indexed by sensory evaluation of the driver when driving the test vehicle on the snow surface of the test course. The index of snowiness means that the index of a conventional example, which will be described later, is 100, and the larger the index, the better the snow performance. Snowiness includes braking / driving and maneuvering performance on a snowy road surface.

Tables 1-4 show the specifications and evaluation results for each tire.
The tread pattern of the conventional example is obtained by replacing the center land portion 60 and the intermediate land portions 62a and 62b shown in FIG. 2 with the tread pattern shown in FIG. Specifically, the tread pattern of the conventional example includes the region of the center land portion 60 provided with the center lug groove 47 and the sipe 56c shown in FIG. 5, the intermediate land portion 62a provided with the intermediate lug groove 50a and the sipe 56a. And an intermediate land portion 62b provided with intermediate lug grooves 50b and sipes 56b. FIG. 5 is a diagram for explaining a part of a conventional tread pattern.

The tread patterns of Examples 1 to 14 and Comparative Examples 1 to 4 are each based on the tread pattern shown in FIG. 2 in which the groove and sipe width, the groove and sipe depth, and the groove are aligned to predetermined values. The tread pattern is modified according to the specifications.
“Inclination in the lower right direction” of the “inclination direction” of the center lug grooves 46 and 47, the intermediate lug grooves 50a, 50b and 51a, and the sipes 56a and 56c in Tables 1 to 4 is shown in FIG. The direction inclined to the lower right direction means “lower left direction inclination” means the direction inclined from the upper right to the lower left direction on the paper surface of FIGS. “Presence / absence of bent portion” refers to whether or not the bent portions 51a ₁ and 51a ₂ (see FIG. 3A) and the bent portions 46c ₁ and 46c ₂ (see FIG. 4A) are provided. Further, in the column “Presence / absence of bent portion”, when there is a bent portion, the relationship between the inclination angle with respect to the tire width direction in the inner portion between the bent portions and the outer portion outside the inner portion is shown. The portion between the "groove depth" is the center lug grooves 46, with respect to the groove depth of the intermediate lug groove 51a, an open end of the second side of the bent portion 46c ₂ and the center lug grooves 46 of the center lug grooves 46, Alternatively, the portion between the opening end of the second side of the intermediate lug groove 51a of the bent portion 51a ₁ and the intermediate lug groove 51a is good or shallow or not with respect to other parts, "constant" means The groove depth is constant, and “partially shallow” means that the part is shallow with respect to the other parts. “Inclined chamfer” refers to the presence or absence of the inclined chamfer 51a ₄ (see FIG. 3A) and the inclined chamfer 46c ₃ (see FIG. 4A).
“←” in Tables 1 to 4 means the same as the contents of the left column of each column.

From Table 1, it can be seen that the wear resistance and snow resistance are improved by making the lug grooves provided in the regions of the center land portion 60 and the intermediate land portion 62a and the sipe inclination directions opposite to each other.
From Table 2, one end of the sipe provided in the region of the center land portion 60 and the intermediate land portion 62a communicates with the lug groove, and the other end communicates with the inner circumferential main groove or the outer circumferential main groove. It is understood that this is preferable from the viewpoint of improving the snow property, and the lug groove provided in the region of the center land portion 60 and the intermediate land portion 62a is a bent lug groove formed of two bent portions, and the bent portion It can be seen that the inclination angle of the inner part sandwiched between the tires in the tire width direction is higher than that of the outer part from the viewpoint of improvement in wear resistance and snow resistance.
From Table 3, it can be seen that it is preferable to provide an inclined chamfer in the bent lug groove from the viewpoint of improving the snow property. Furthermore, from comparison between Example 5 in Table 2 and Example 6 in Table 3, it is found that “partially shallow” is preferable from the viewpoint of improvement in wear resistance.
From Table 4, it can be seen that the area of the center land portion 60 and the intermediate land portion 62a is preferably a microgroove region from the viewpoint of improving snow characteristics.

  As mentioned above, although the pneumatic tire of this invention was demonstrated in detail, this invention is not limited to the said embodiment and Example, In the range which does not deviate from the main point of this invention, you may make a various improvement and change. Of course.

DESCRIPTION OF SYMBOLS 10 Pneumatic tire 10T Tread part 10S Side part 10B Bead part 12 Carcass ply layer 14 Belt layer 16 Bead core 18 Tread rubber member 20 Side rubber member 22 Bead filler rubber member 24 Rim cushion rubber member 26 Inner liner rubber member 30 Belt cover layer 40 Tread Patterns 42a, 42b Inner circumferential main grooves 44a, 44b Outer circumferential main grooves 46, 47 Center lug grooves 50a, 50b, 51a Intermediate lug grooves 54a, 54b, 55a Shoulder lug grooves 56a, 56b, 56c, 55b Sipe 60 Center land part 62a, 62b intermediate land portion 64a, 64b shoulder land portion _{51a 1, 51a 2, 46c 1} , 46c 2 bent portion _{51a 4, 50a 1, 46c 3} , 46c 4, 50b 1 inclined chamfer 70 microgrooves 72 Groove

Claims (8)

A pneumatic tire having a tread pattern,
The tread pattern is an asymmetric pattern,
A pair of inner circumferential main grooves extending in the tire circumferential direction;
A pair of outer circumferential main grooves provided on the outer side in the tire width direction of the inner circumferential main grooves and extending in the tire circumferential direction;
Crossing each of the two intermediate land portions defined by the inner circumferential main groove and the outer circumferential main groove and the center land portion defined by the pair of inner circumferential main grooves, both ends are in the inner circumference. A plurality of lug grooves that divide the intermediate land portion and the center land portion into block elements by communicating with a direction main groove or the outer circumferential main groove;
A plurality of sipes provided in regions of the intermediate land portion and the center land portion, at least one end of which communicates with the inner circumferential main groove or the outer circumferential main groove;
Each of the lug grooves is inclined toward the first direction of the tire circumferential direction with respect to the tire width direction when going from the first side in the tire width direction to the second side,
All of the sipes are oriented in a second direction opposite to the first direction in the tire circumferential direction with respect to the tire width direction when going from the first side in the tire width direction to the second side. A pneumatic tire characterized by being inclined.   One end of each of the sipes communicates with one of the inner circumferential main grooves or one of the outer circumferential main grooves, and the other end communicates with one of the lug grooves. Item 2. The pneumatic tire according to Item 1. Of the two intermediate land portions, the first intermediate land portion located on the first side in the tire width direction includes, as the lug groove, two first bent portions in which the inclination angle of the extending groove changes. A first bent lug groove is provided,
The inclination angle of the groove with respect to the tire width direction of the first inner portion sandwiched between the two first bent portions of the first bent lug grooves is the two first bent lug grooves. The pneumatic tire according to claim 1, wherein the pneumatic tire is larger than a first outer portion located outside the bent portion. The edge length along the inner circumferential main groove of the two block elements sandwiching the first bent lug groove of the first intermediate land portion from both sides in the tire circumferential direction is different,
Of the first bent lug groove, the groove depth of the portion between the open end communicating with one of the inner circumferential main grooves and one of the first bent portions located on the first side is The pneumatic tire according to claim 3, which is shallower than a groove depth of a portion other than the portion.   Among the first bent lug grooves, one groove wall surface between one of the first bent portions located on the first side and an open end communicating with one of the outer circumferential main grooves is 5. The pneumatic tire according to claim 3, wherein an inclined chamfer is provided in which a groove wall is inclined so that a groove width is widened toward an opening end communicating with one of the outer circumferential main grooves.   A plurality of linear micro grooves having a groove depth shallower than the groove depth of the lug groove and narrower than the groove width of the lug groove extend in parallel with each other on the tread surface in contact with the ground of the center land portion. The pneumatic tire according to any one of claims 1 to 5, wherein a micro-groove region is provided.   Of the intermediate land portion, the tread surface in contact with the ground of the first intermediate land portion located on the first side with respect to the center land portion has a groove depth shallower than the groove depth of the lug groove, The pneumatic tire according to any one of claims 1 to 6, wherein a plurality of linear microgrooves whose groove width is narrower than the groove width of the lug grooves are provided with microgroove regions extending in parallel with each other. .   A shoulder land portion is provided on the outer side in the tire width direction of each of the outer circumferential main grooves, and a shoulder lug groove extending in the tire width direction is provided in each region of the shoulder land portion. Also, when going from the first side in the tire width direction to the second side, the tire tilts in the tire circumferential direction toward the second direction with respect to the tire width direction. Or a pneumatic tire according to item 1.

Images