JPH01208205A - Structure of tread part of pneumatic tire - Google Patents

Abstract

PURPOSE:To provide compatibility for the step wear resistance and the wear resistance of a tire having a central block and a side block by forming the central block so that the kickout side vertical surface rises mildly and the stamp-in side vertical surface rises steeply, and by forming the edge of the stamp-in side vertical surface sharply. CONSTITUTION:When a tire tread is equipped with a central block 2 and a side block 3 by a circumferential groove and an axial groove, the rising angle alphaof the kickout side vertical surface 8 of the central block 2 shall be mild while the rising angle beta of the stamp-in side vertical surface 7 be steep, and alpha-beta is set to approx. 5-40 deg. with the groove width W held constant. The edge 7A of the stamp-in side vertical surface 7 is formed sharply. The stamp-in side of the side block 3 and the vertical surfaces 9, 10 on the kickout side are set in the same manner, and in case the shoulder rigidity is lower than the center, the condition (alpha-beta)>(alpha1-beta1) shall be met, while in case the center rigidity is lower than the shoulder, (alpha1-beta1)>(alpha-beta). Thereby the wear balance of the center part and shoulder part can be held.

Description

DETAILED DESCRIPTION OF THE INVENTION (Field of Industrial Application) The present invention relates to the structure of a tread portion of a pneumatic tire.

(Prior Art) The tread of a tire includes a central block surrounded by circumferential and axial grooves and located on the axial center side of the tire, and a tire tread surrounded by circumferential and axial grooves. A pneumatic tire in which a large number of side blocks located on both sides in the axial direction are arranged in the circumferential direction of the tire was developed in 1983-
It is known from Publication No. 159203.

(Problems to be Solved by the Invention) In the conventional tire described above, the kicking side elevation A and the stepping side elevation B of the center block and the side pro-7 are both shown in FIG. Like the axial direction? The rising slope from iXC was the same.

That is, α2. β3 was the same.

For this reason, α2. As β3 increases, the block rigidity increases and the attachment stability improves, but on the other hand, the actual ground contact area decreases and the wear resistance decreases.

On the contrary, α2. As βY becomes smaller, the wear resistance improves, but on the other hand, the attachment slipperiness decreases.

SUMMARY OF THE INVENTION An object of the present invention is to enable contradictory functions of the kicking side and the stepping side to be performed by adjusting the slope of the block elevation.

(Means for Achieving the Object) The present invention provides a central block located on the axial center side of the tire surrounded by circumferential grooves and axial grooves, and a central block surrounded by circumferential grooves and axial grooves. In order to achieve the stated purpose, the following technical measures are taken in a tire in which a large number of side blocks surrounded by grooves and located on both sides in the axial direction of the tire are arranged in the circumferential direction of the tire.

That is, in the present invention, the central block 2 has a stepping-in side elevational surface 7 and a kicking-out side elevational surface 8 that are inclined and rising from the axial direction m5,
It is characterized in that the rise of the kick-off side elevation 8 is gradual, the rise of the depression-side elevation 7 is steep, and the edge 7A of the depression-side elevation 7 is sharp.

Further, in the present invention, the central block 2 has a stepping-in side elevation 7 and a kick-out side elevation 8 that rise at an inclination from the axial groove 5, and the kick-out side elevation 8 has a gradual rise and a stepping-in side elevation. The rise of the vertical surface 7 is steep, the edge 7A of the stepping-in side vertical surface 7 is sharp, and the vertical surface 9 of the side block 3 is sharp. Like each elevation 7.8 of the central block 2, IO has a gentle kick-off side and a steep stepping-in side, and each elevation 7.8 of the central block 2
, 8 and each elevation 9.10 of the side block 3, the corresponding elevations 7, 9.8° 10 have different slopes.

(Function) When the pneumatic tire rotates in the direction of the arrow and travels, the depression-side edge 7A of the central block 2 is sharp, ensuring reliable depression, and good kick-off on the kick-out side.

Therefore, attachment compatibility can be improved without reducing wear resistance.

Furthermore, the side block 3 also has the same effect as described above,
At this time, the elevation at the center and shoulder is 7°9.8.10
Since the inclinations of the two sides are different, it is possible to maintain a balance between the wear of the center and the shoulder and improve the attachment stability without impairing the wear resistance.

In order to ensure the above-mentioned effect, (α-β)≧5°~40
', and if (α1-βl)≧5° to 40° and the shoulder stiffness is lower than the center, then it is set as (α-β)>(α1-βI), and the center stiffness is lower than the shoulder stiffness. If it is lower than (α1−βl)〉
(α−β).

(Example) Embodiments of the present invention will be described in detail below with reference to the drawings.

Figures 1, 2, and 3 all show a part of the tread of a pneumatic tire in plan view, where 1 is the tread, 2 is the center block, and 3 is the side block. be.

The center blocks 2 are surrounded by circumferential grooves 4 and axial grooves 5 near the center in the axial direction of the tire (horizontal direction in the figure), and are arranged in large numbers in the tire circumferential direction (vertical direction in the figure).

The side blocks 3 have circumferential grooves 4 on both sides in the axial direction of the tire.
They are surrounded by grooves 5 in the axial direction and are arranged in large numbers in the circumferential direction of the tire.

In addition, in FIG. 1, the center block 2 and the side blocks 3 are arranged at the same pitch without a phase shift in the circumferential direction, but as shown in FIGS. 2 and 3, they are arranged with a phase shift in the circumferential direction. It may also be arranged as follows.

In addition, in the figure, 0-0 is the center of the tire (meridian), and 6
indicates the direction of tire rotation.

Referring to FIG. 4, the central block 2 has a stepping-in side elevation 7 and a kicking-out side elevation 8 rising up from the axial inner groove 5, and the elevation 7 is steep and its edge 7A is steep. It is said to be sharp, and the elevation 8 is said to be gentle.

That is, assuming the groove width is constant (α-β)≧5°~40
”.

If (α-β)>40', it may not be possible to satisfy both wear resistance and attachment stability, and if (α-β)>40', the actual ground contact area may be extremely reduced and wear resistance may deteriorate. There is.

In FIG. 5, the inclination angle α1 between the stepping-in side elevational surface 9 and the kicking-out side elevational surface 10 of the side block 3 is shown. β1 is assumed to be the same in both cases.

In FIG. 6, the inclination angle α1 of the elevational surface 9 and the elevational surface 10. β.

(α1-βl)≧5° to 40°, and the elevational surface 7.8 of the central block 2 is the same as that in FIG.

Therefore, when the stiffness of the shoulder part is lower than that of the center part, (α-β)>(α1-βl), and when the stiffness of the center part is lower than the shoulder part, (α.

−βI)〉(α−β).

This results in the corresponding elevations 7, 9.8.10 of the elevations 7, 8 of the central block 2 and the elevations 9.10 of the side blocks 3.
This makes it possible to maintain a balance between wear in the center and part of the shoulder, and to improve attachment flexibility without impairing wear resistance.

(Effect of the invention) The present invention is as described above, and the first feature thereof (Claim 1
), there is a difference in the elevation slope between the stepping-in side and the kicking-out side.
It is possible to improve attachment compatibility without reducing wear resistance.

Moreover, according to the second feature (claim 2), in addition to the above-mentioned advantages, it is possible to maintain a balance between wear between a portion of the center and a portion of the shoulder.

The present invention has the above advantages and is useful as a structure for a tread portion of a pneumatic tire (radial, bias).

[Brief explanation of the drawing]

1 to 3 are plan views showing three embodiments of the present invention, FIG. 4 is a sectional view taken along line A-1m in FIGS. 1 to 3, and FIG. 6 is a sectional view taken along line B--B in FIG. 2 and line B--B in FIG. 3, and FIG. 7 is a sectional view of a conventional example. 1...Tread section, 2...Central block, 3...
- Side block, 5... Axial groove, 7.9... Kick-out side elevation, 8.10... Kick-out side elevation.

Claims (2)

[Claims] (1) In the tread of the tire, there is a central block located on the axial center side of the tire surrounded by circumferential grooves and axial grooves, and both sides of the tire axial direction surrounded by circumferential grooves and axial grooves. In a case where a large number of side blocks located on the sides are arranged in the tire circumferential direction, the central block 2 has a stepping-in side elevation 7 and a kick-out side elevation 8 that stand up at an angle from the axial groove 5. , a tread portion of a pneumatic tire characterized in that the rise of the rising side elevation 8 is gradual, the rising of the stepping side elevation 7 is steep, and the edge 7A of the stepping side elevation 7 is sharp. structure. (2) The central block 2 has a stepping-in side elevation 7 and a kick-out side elevation 8 that rise at an angle from the axial groove 5, and the kick-out side elevation 8 rises gradually, and the stepping-in side elevation 7 The rise is said to be rapid,
The edge 7A of the stepping-in side elevation 7 is sharp, and the rising sides 9 and 10 of the side block 3 are also gentle on the kicking side and steep on the stepping side, like the respective elevations 7 and 8 of the central block 2. It is characterized in that the corresponding vertical surfaces 7, 9, 8, 10 of the central block 2 and the vertical surfaces 9, 10 of the side blocks 3 have different slopes. The structure of the tread of a pneumatic tire.