JPH0659765B2 - Heavy vehicle tires - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial field of application] The present invention enables a tire having a block pattern to maintain its grip in the initial stage of use, reduce heel and toe wear in the middle and later stages, and enable year-round use. A tire for a heavy vehicle.

[Conventional technology]

As a tread pattern for tires for heavy vehicles such as trucks and buses that are specified in JISD4202 as tires for trucks and buses, rib patterns that emphasize driving performance on highways, unpaved road surfaces, snow and ice roads, mud roads, etc. Block patterns or rib lug patterns are often used, which emphasize grip when driving on rough roads.

Also, when traveling on a paved road surface with a block pattern tire, face the traveling direction of the block, and the side that comes in contact with the road surface first when rolling, that is, the side that contacts the ground later, that is, the kicking side. Heel-and-toe wear, in which wear progresses rapidly on the delivery side, due to slippage with the road surface caused by a decrease in ground contact pressure, occurs. Such heel-and-toe wear is unsightly.

In order to solve this problem, conventionally, a method of reducing the groove width of the lateral groove or inclining the lateral groove at a large angle with respect to the tire rotation axis has been adopted.

However, these methods sacrifice the grip performance, which is the function originally intended by the lateral groove, from the beginning of wear.

The present invention, in a tire having a block pattern, maintains the grip performance by orienting the lateral grooves in the tire axial direction from the initial stage to the middle stage of abrasion, and in the vicinity of the middle stage and thereafter, the lateral side grooves are inclined to prevent the wear on the kicking side. The purpose of the present invention is to provide a heavy-duty tire that can reduce heel and toe wear and can be used all year round.

[Means for solving problems]

The present invention, the tread surface, a plurality of vertical grooves extending in the tire circumferential direction, and a block pattern having a plurality of rows of block groups consisting of blocks spaced in the tire circumferential direction by the lateral grooves intersecting the vertical grooves In the tire, which is a block of at least two rows of blocks adjacent to the tire equator, the ridgeline formed by the tread surface of the groove walls sandwiching the lateral groove in the initial stage of wear forms an angle θ1 with a line parallel to the tire rotation axis.
Is substantially 0, and the angle θ2 formed by the groove wall at a substantially intermediate position of the height of the groove wall with respect to a line parallel to the tire rotation axis is set larger than the angle θ1 of the ridge line. A heavy vehicle tire characterized by the above.

[Action]

By setting the angle formed by the ridgeline of the tread surface of the groove wall in the initial stage of wear to be substantially 0 with respect to the tire rotation axis,
Maintains grip at the initial stage of wear.

By increasing the angle of the groove wall with respect to the tire axial direction line at a substantially intermediate height position, it is possible to suppress so-called heel and toe wear, which tends to occur near the middle stage of wear and which is caused by early wear on the kicking side. .

Therefore, for example, when tires are installed in winter when there are many opportunities to travel on snow and ice roads, the grip is good and the running performance is maintained, while in the spring after the snow melts and in the middle of wear after the early summer. As a result, heel and toe wear during traveling on a paved road can be reduced and noise can be reduced, and the tire can be adapted to a traveling state that changes throughout the year as a tire for heavy vehicles such as trucks and buses.

〔Example〕

 An embodiment of the present invention will be described below with reference to the drawings.

In the drawings, a heavy vehicle tire (hereinafter referred to as a tire) 1 of the present invention has a vertical groove G1 passing on the tire equator CO, and vertical grooves G2, G2 on both sides of the vertical groove G1 on the tread surface. By forming an inner rib between the vertical grooves G1 and G2 and an outer rib between the vertical groove G2 and the tread edge, and forming lateral grooves g1 ... In the inner ribs and lateral grooves g2 ... In the outer ribs. , Blocks 2 ...
And the two groups of blocks 4 and 4 in the two rows adjacent to the tire equator CO arranged in the tire axial direction and the two groups of blocks 5 and 5 in the outer row along the tread edge.

The vertical grooves G1 and G2 are both zigzag grooves of the same size, and the horizontal groove g1 has a single V-shape with one pitch.
Since the lateral grooves g2 are provided every 1.5 pitches, and the lateral grooves g2 are provided every 2 pitches, the block 2 of the inner block group 4 has a shorter circumferential length than the block 3 of the outer block group 5. , Suppresses the increase of noise due to synchronization.

Further, the groove walls 1 sandwiching the lateral grooves g1 and g2 of the blocks 2 ...
Ridge line 1 to be the tread surface of 0 or 11 new or early wear
The angles θ1 formed by 5 with respect to the line Y parallel to the rotation axis are substantially 0, and are substantially parallel to the line Y. This improves grip.

Further, the groove walls 10 and 11 sandwiching the lateral groove g1 of the block groups on both sides of the tire equator CO, in this example, the block 2 of the inner block groups 4 and 4, have a height H at a substantially central height position 1 / 2H.
And an angle θ formed with respect to the line Y parallel to the tire rotation axis
2 is larger than the angle θ1. Note that the angle θ2
Is preferably about 5 to 15 degrees larger than the angle θ1 as shown in FIG.

To this end, FIG. 2 shows a sectional view taken along line AA of FIG.
As shown in the cross-sectional view taken along the line BB in the figure, in the groove wall 10 on the kicking side E1, the angle of inclination in a plane orthogonal to the tire rotation axis with respect to the tire radius line X is an angle α1 in the tire axial direction.
From the angle α2. Further, the groove wall 11 on the depression side E2 increases from the angle β1 to the angle β2 in the tire axial direction,
Accordingly, from the angle θ1 of the ridge line 15 to the intermediate height 1
The angle θ2 can be changed to / 2H.

Thus, as compared with the initial stage of wear, the angle θ2 at which the groove walls 10 and 11 form a line Y parallel to the tire rotation axis in the middle stage of wear.
As a result, the heel and toe wear that tends to occur after the middle period of wear is reduced. Note that running noise can be reduced by increasing the angle θ2 with respect to the line Y, and the angle at the groove bottom position is 2 of the intermediate height angle θ2.
It is natural to double.

4 and 5 show another embodiment of the present invention, which is indicated by A- in FIG.
It is shown in a cross-sectional view taken along line A and line BB.

In the present embodiment, the circumferential length is changed from the lengths m1 and n1 to the lengths m2 and n2 in the tire axial direction at a position where the groove walls 10 and 11 have a substantially intermediate height of 1 / 2H. By providing the shelf-like steps 16 and 17, the angle θ2 of the groove wall with respect to the line Y parallel to the tire rotation axis after the middle wear period is θ2.
Is large.

As described above, the tire of the present invention has an angle of the ridge line 15,
The angle of the approximate middle height can be changed in a stepped manner,
It is also possible to use the step portion and the inclined groove wall shown in FIGS. In the embodiment of FIGS. 4 and 5, the angle θ1 is constant from the initial stage of wear to the step portions 16 and 17.
The angle from the step portions 16 and 17 to the groove bottom is the angle θ2.
It becomes constant at.

Other specifications such as the widths of the vertical grooves G1 and G2 and the horizontal grooves g1 and g2 can be appropriately selected by those skilled in the art according to the purpose.

〔The invention's effect〕

As described above, the tire of the present invention maintains gripping properties at the initial stage of wear, and thus has good runnability in winter, which is often found on bad roads such as snow and ice roads. After that, particularly, heel and toe wear caused by wear on the kicking side can be effectively prevented, noise can be reduced, and even year-round use in heavy vehicles such as trucks and buses is possible.

[Brief description of drawings]

1 is a partial front view of a tire of the present invention, FIG. 2 and FIG. 3 are sectional views taken along line AA, BB of FIG. 1, FIG. 4 and FIG.
The drawings are AA sectional views and BB sectional views of FIG. 1 showing another embodiment. G1, G2 ... Vertical groove, g1, g2 ... Horizontal groove, 2, 3 ... Block, 4, 5 ... Block group, 10, 11 ... Groove wall.

Claims (1)

[Claims] 1. A block pattern having a plurality of rows of blocks extending in the tire circumferential direction on a tread surface, and a block group of a plurality of rows composed of blocks spaced in the tire circumferential direction by lateral grooves intersecting with the vertical grooves. The block of at least two rows of blocks adjacent to the tire equator has an angle formed by a ridgeline formed by the tread surface of the groove wall sandwiching the lateral groove at the initial stage of wear with respect to a line parallel to the tire rotation axis. θ1 is set to substantially 0, and an angle θ2 formed by the groove wall at a substantially intermediate position of the height of the groove wall with respect to a line parallel to the tire rotation axis is larger than the angle θ1 of the ridge line. A heavy vehicle tire characterized by the above.