JP5620144B2 - Pneumatic tire - Google Patents

Description

  The present invention relates to a pneumatic tire, and more particularly to a pneumatic tire used for an automobile traveling on a snowy road, and particularly proposes a technique for achieving both high performance on ice and high performance on snow.

  In a conventional pneumatic tire, for example, as described in Patent Document 1, in order to improve drainage performance on a wet road surface and handling stability on a dry road surface, an inclination extending from the vicinity of the tire equator to the tire shoulder end on the tread surface It is common to have a groove and a circumferential groove extending in the tire circumferential direction across the inclined groove.

  However, when running on snow with such tires, the snow that has been stepped on in the inclined groove during running will escape to the tread end side through the inclined groove, and high snow column shearing force due to the solidified snow will be obtained. Since it was not possible, the lack of performance on snow could not be denied.

Japanese Patent Laid-Open No. 10-24706

  Accordingly, the present invention provides a pneumatic tire that is particularly improved on snow performance without reducing on-ice performance.

The pneumatic tire according to the present invention is formed by disposing each inclined groove extending on the tread surface from the vicinity of the tire equatorial plane toward the respective tread ends in an inclining direction away from each other. A plurality of recesses are provided at the bottom of each inclined groove, and a sub-groove extending in the tread circumferential direction or the tread width direction is provided in each inclined groove with a groove width narrower than the inclined groove. The groove bottom is made continuous with the recess of the inclined groove, and the sub-groove intersects with the inclined groove extending adjacent to the tread width direction .

  In addition, the inclined groove | channel here can also be extended in forms, such as not only a linear extended form but zigzag shape, a wave shape, and a crank shape.

  By the way, it is preferable that the ratio S2 / S1 of the area S2 of the inclined groove to the total area S1 of the groove in the ground contact state of the tread surface satisfies the range of 0.6-1.

  In the pneumatic tire according to the present invention, by providing a plurality of concave portions at the bottom of each inclined groove extending inclinedly from the vicinity of the tire equatorial plane toward the tread end, the tire rolls when traveling on a snowy road. As a result, snow enters the inclined grooves and eventually the recesses, and in particular, a large amount of snow is pressed in the recesses with a large volume of the groove, and the snow that has been pressed by the inclined grooves remains in the recesses. It is possible to effectively obtain a snow column shearing force for shearing a column) by a groove wall such as an inclined groove. As a result, the drivability on snow can be improved.

(A) It is the partial expanded view of the tread pattern which shows one Embodiment of the pneumatic tire of this invention, (b) is an enlarged end elevation in alignment with the BB line of (a). (A) It is the partial expanded view of the tread pattern which shows other embodiment of the pneumatic tire of this invention, (b) is an enlarged end elevation in alignment with the BB line of (a).

Hereinafter, the pneumatic tire of the present invention will be described in detail with reference to the drawings.
FIG. 1A is a partial development view of a tread pattern showing an embodiment of a pneumatic tire according to the present invention, and FIG. 1B is an enlarged end view taken along line BB in FIG.
Here, the reinforcing structure inside the tire is the same as that of a general radial tire or bias tire, and therefore illustration is omitted.

  In the figure, reference numeral 1 denotes the entire tread surface. In the tread surface 1, a single circumferential groove 2 extending in the tread circumferential direction is disposed on the tire equator surface, and each tread is provided from the circumferential groove 2 in the figure. A plurality of inclined grooves 3 extending in an arc shape at an inclination angle of 20 to 85 ° are arranged in directions away from each other toward the end.

  In the figure, the circumferential groove 2 and the two inclined grooves 3 divide a block 4 having a substantially rectangular shape, and the blocks located on both sides of the circumferential groove 2 are arranged so as to be shifted by approximately a half pitch in the tread circumferential direction.

  In each inclined groove 3, three substantially triangular sub-grooves 5 extending in the tread circumferential direction are arranged along the inclined groove 3, and the sub-grooves end in the block 4.

  Further, in this pneumatic tire, a plurality of, in the figure, three recesses 6 are provided in the groove bottom of each inclined groove 3, and preferably the groove bottom of the sub-groove 5 is continuous with the recess of the inclined groove.

  FIG. 2: is the partial expanded view of the tread pattern which shows other embodiment of the pneumatic tire of (a) this invention, (b) is an enlarged end elevation in alignment with the BB line of (a).

  In this embodiment, reference numeral 11 in the drawing shows the entire tread surface, and the tread surface 11 is provided with a single circumferential groove 12 extending in the tread circumferential direction on the tire equator surface in the figure. A plurality of inclined grooves 13 extending in a substantially linear manner with an inclination angle of 30 to 60 ° are arranged in directions away from 12 toward the respective tread ends.

  In the figure, a substantially rectangular block 14 is defined by the circumferential groove 12 and the two inclined grooves 13, and the blocks 14 located on both sides of the circumferential groove are arranged with a substantially half pitch shift in the tread circumferential direction.

  Each inclined groove 13 is provided with two sub-grooves 15 extending in the tread width direction in the tread half width along the inclined groove 13, and the sub-grooves 15 intersect with the inclined grooves adjacent in the tread width direction. And the process ends in block 14.

  Further, in this pneumatic tire, a groove bottom of each inclined groove 13, a concave portion 16 at the bottom of the inclined groove in the figure, and a concave portion 17 that extends over the bottom of the inclined groove 13 and the auxiliary groove 15 are provided.

  In this embodiment, the snow that has moved in the sub-groove 15 collides with the inclined groove 13 and is held at the intersection of the inclined groove 13 and the sub-groove 15 so that the snow column does not escape in particular. Snow can be strongly stepped and solidified, the shear strength of the snow column in the groove is increased, and a high snow column shear force can be obtained.

  In such a pneumatic tire, more preferably, the auxiliary grooves 5 and 15 extending in the tread circumferential direction or the tread width direction are arranged in the inclined grooves 3 and 13 with a groove width narrower than the inclined grooves 3 and 13. In addition, by making the bottoms of the sub-grooves 5 and 15 continuous with the recesses of the slant grooves 3 and 13, the snow in the slant grooves 3 and 13 and the sub-grooves 5 and 15 can be stepped on, especially at the intersections. Since it is hardened, the shear strength of the snow column in the groove increases, and a high snow column shear force can be obtained.

  Preferably, the ratio S2 / S1 of the area S2 of the inclined grooves 3, 13 to the total area S1 of the grooves in the ground contact state of the tread tread satisfies 0.6 to 1, and by setting this range, the inclined grooves 3, It is possible to reduce the flow of snow in the snow 13 and to improve the snow column shear force of the snow that has been compacted in the inclined grooves 3 and 13.

And preferably, the depths h ₁ and h ₂ from the groove bottoms of the circumferential grooves 2 and 12 or the inclined grooves 3 and 13 of the recess are the grooves from the tread surface of the circumferential grooves 2 and 12 or the inclined grooves 3 and 13. The heights t ₁ and t ₂ are ½ or more to 1 or less of the height t ₁ , and by setting the height within this range, snow can actively enter the recess and stop the flow of snow in the inclined grooves 3 and 13.

Next, a tire having a structure as shown in FIG. 1 and a size of 225 / 45R17 was prototyped, and as shown in Table 1, reference tires 1 and 2 in which the respective specifications were changed and comparison were made. For each example tire, the driving performance on the snow road surface and the braking performance on the ice road surface were measured.
In addition, since the comparative example tire does not require modification for the structure other than the tread portion, it was assumed to be similar to the reference example tire.

[Driving performance on snowy road surface]
For each of the reference example tires 1 and 2 and the comparative example tire, it was assembled on a rim having a size of 17 × 7 J, mounted on the vehicle with an internal pressure of 240 kPa, and the time required to accelerate from 10 km / h to 45 km / h Index evaluation was performed, and the evaluation results are shown in Table 2.
In addition, it shows that it is excellent in the drive performance of the road surface on snow, so that the index | exponent in a table | surface is large.

[Brake performance on ice surface]
Each of the reference example tires 1 and 2 and the comparative example tire was assembled on a rim of size 17 × 7 J, mounted on the vehicle with an internal pressure of 240 kPa, and fully braked from the running state on the ice at a speed of 30 km / h. The braking distance is evaluated as an index, and the evaluation results are shown in Table 2.
In addition, it shows that it is excellent in the braking performance of the road surface on ice, so that the index | exponent in a table | surface is large.

From the results in Table 2, the reference example tire 1 can improve the driving performance on the snow road surface and the braking performance on the ice road surface compared to the comparative example tire, and the reference example tire 2 is The driving performance on the snowy road surface could be improved without reducing the braking performance on the snowy road surface.

1,11 tread surface 2,12 circumferential groove 3,13 inclined groove 4,14 block 5,15 sub-groove 6,16,17 concave portion

Claims (2)

In the pneumatic tire formed by disposing each inclined groove extending in a direction away from each other toward the tread end from the vicinity of the tire equatorial plane on the tread surface,
A plurality of recesses are provided at the bottom of each inclined groove ,
In each inclined groove, a sub-groove extending in the tread circumferential direction or the tread width direction is arranged with a groove width narrower than the inclined groove, and the groove bottom of the sub-groove is continuous with the concave portion of the inclined groove,
A pneumatic tire characterized in that the sub-groove intersects an inclined groove extending adjacent to the tread width direction . The pneumatic tire according to claim 1, wherein the ratio S2 / S1 of the area S2 of the inclined groove to the total area S1 of the groove in the ground contact state of the tread surface satisfies a range of 0.6-1.

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