JPS63130409A - Pneumatic tyre for vehicle running on irregular ground - Google Patents

Abstract

PURPOSE:To improve straight running ability and turning ability, in a title tyre having a patter of Buddhist architecture, by a method wherein the inclination angle of a side block and a ratio of a total of the length of sloped sides to the length of the whole periphery of a side block are respectively specified. CONSTITUTION:A side block 5 formed on a tread 2 is formed in a trapezoid having a rhombic top surface 5A, and is formed with two sides in parallel to an equator line O-O and two sides 5B and 5C, an inclination angle theta of 30-60 deg. with a rotation axis X-X of a tyre. The blocks are arranged in a manner to have the front and the rear in a rotation direction Y at interblock pitches P1 equal to a pitch P of a central block 4. Further, a total of the lengths of the inclination sides 5B and 5C of the side block 5 is set to a value being 0.25-0.8 times as long as the length of the whole periphery of the side block. This constitution enables improvement of straight running ability and turning ability.

Description

DETAILED DESCRIPTION OF THE INVENTION (Field of Industrial Application) The present invention relates to an extremely low internal pressure tire used for running on rough terrain.

(Prior Art) Buggy tires have been known as ultra-low internal pressure tires for running on rough terrain. Buggy vehicles are primarily used for traveling on muddy, grassy, snowy, and sandy areas, and are used for sports, leisure, or competition.

Also, 7...; A gear vehicle may be a three-wheeled or four-wheeled vehicle, and an ultra-low internal pressure of around 0.15 kg/crA is applied. For this reason, the reinforcing structure of the tire is to use virtually all rubber without reinforcement, to apply a cord layer only in the trend area, or to apply a carcass with cords arranged in the radial direction between both beads of one ply. A so-called modified radial structure is known in which the tread part does not use the belt layer that is normally used in the crown part of the carcass in this type of structure. On the other hand, the tread part has blocks or lugs protruding parallel to the rotation axis of the tire.
A structure in which protruding block rows or lugs are regularly arranged at predetermined intervals in the circumferential direction is known.

However, such a trend structure has no problem with the driving force or braking force that is applied when driving straight, but when steering or turning, blocks or lugs are arranged horizontally on the tread at right angles to the circumferential direction ( There was a problem in that the ground gripping force was insufficient in response to the force acting in the horizontal direction (lateral force) and the horizontal grooves were parallel, resulting in poor maneuverability.

Therefore, there is a pneumatic tire for vehicles traveling on rough terrain (prior art) proposed in Japanese Patent Application Laid-Open No. 60-33104.

In other words, in this conventional technology, the trend located in the center is toroidally connected to both sidewalls, and a large number of blocks are protruded from the periphery of the tread so as to be arranged generally horizontally. The upper block is
There is a circumferential offset X corresponding to 0.3 to 0.7 times the circumferential block length between blocks adjacent in the tire rotational axis direction, and at the same time, blocks extending from the center of the tread to the left and right to the tread edge The blocks are arranged in rows at an average inclination angle of 10 to 35 degrees with respect to the tire rotation axis direction, thereby forming a herringbone pattern of blocks in the circumferential direction.

(Problems to be Solved by the Invention) However, in this prior art, when the vehicle turns,
There was a problem in that the ground gripping force was insufficient because the blocks had fewer inclined sides, and as a result, turning performance was poor.

The present invention has been achieved by devising the shape and inclination angle of the side blocks arranged in a herringbone pattern on the trend.
．． The purpose is to improve straight-line safety and turning performance.

(Means for Solving the Problems) The present invention has a tread located in the center connected to both sidewalls in a toroidal manner, and a central block located on the equator line on the circumference of the tread, and a central block located on the equator line on both sides of the equator line. The above object has been achieved by taking the following technical measures in a tire having symmetrically positioned side blocks arranged and projecting in a herringbone pattern in the circumferential direction.

That is, in the present invention, each of the side blocks 5 has inclined sides 5B and 5C at the front and rear in the rotation direction Y, each having an inclination angle θ of 30° to 60° with respect to the tire rotation axis XX, and It is characterized in that the total length of the inclined sides 5B and 5C is 0.25 to 0.8 times the total peripheral length of the side block 5.

(Example) The tire 1 according to the present invention has a tread 2 located in the center part.
is toroidally connected to both side walls via the shoulder 3, and is made of rubber or other elastic material.

Although this tire l has a core at the bead part (not shown) and a carcass that is wound up and connected to each other, the number of plies and the presence or absence of this carcass are not limited, and the tire when assembled with a rim Internal pressure is 0.15kg
The pressure is extremely low, around /ca1.

On the circumference of the tread 2, there is a central block 4 located on the equator line 0-0 of the tire 1 and an equator line 61 o -.

Side blocks 5 are arranged in a herringbone pattern in the circumferential direction and protrude from each other in a herringbone pattern.

The central block 4 has a trapezoidal cross section with a rectangular top surface 4A, with the long side of the top surface 4A running parallel to the equator line 0-0, and the short side running parallel to the tire rotation axis XX. A predetermined interval (pitch) P in the circumferential direction on the equator line 0-0
are arranged in rows.

The side block 5 has a trapezoidal cross section with a rhombic top surface, and two opposing sides of the top surface 5A are equator yAo −.

The other two opposing sides are parallel to the tire rotation axis
The blocks are arranged circumferentially at an inclination angle θ of 30° to 60” with respect to X, and the blocks are arranged in a herringbone pattern in the circumferential direction. It is assumed that it does not run parallel to the rotation axis XX.

That is, the side block 5 is connected to the tire rotation axis X −X
The tire has inclined sides 5B and 5C at the front and rear in the tire rotation direction Y, each having an inclination angle θ in the range of 30° to 60°, preferably 40° to 50°.

Further, the total length of the inclined sides 5B and 5C of the side block 5 is set to be 0.25 to 0.8 times the total peripheral length of the side block 5.

Here, the length of the inclined sides 5B and 5C is 0 of the total peripheral length.
．． If it is less than 25 times, the ground gripping force when turning the vehicle will be insufficient and the turning performance will be poor, and if it is more than 0.8 times, the ground gripping force will be sufficient, but the side will be inclined. The straight-line safety is inferior from 0.25 to 0.8.
The range is said to be double that.

In addition, if the inclination angle θ is less than 30°, the turning performance will be poor;
If the angle is 0° or more, the straight-line safety will be poor, so the angle θ is set in the range of 30° to 60°.

Examples of arrangement patterns of blocks 4 and 5 will be explained with reference to FIGS. 2 to 7.

Fig. 2 shows an example in which the inclination angle θ of the side block 5 is 40°, and Fig. 3 shows an example in which the angle θ is 20° and the slope side ratio is 0.333.
Figure 4 shows an example where the angle θ is 60' and the slope side ratio is 0.333 times, and Figure 5 shows an example where the angle θ is 40°.
and the slope ratio is 0. ．． Figure 6 shows an example where the angle θ is 40° and the slope ratio is 0.2 times.
The figure shows an example in which the angle θ is 40° and the slope side ratio is 0.8.

Figures 3 and 4 show the minimum and maximum limits for the inclination angle θ, and as shown in Figure 8, the turning performance tends to be poor, and Figure 5 shows the poor turning performance and straight-line safety. All of them are good, and Fig. 6 shows that straight-line safety is good, but the slope side ratio is 0.2 times less than the minimum limit value, so as shown in Fig. 9 (turning performance is relatively poor, Although the turning performance in Fig. 7 is good, since the slope side ratio is 0.8 times the maximum limit value, it is relatively inferior in terms of straight-line safety.

In addition, in FIG. 2, 7 is a groove, which is formed on the top surface of the block 4.5 in a shape similar to this top surface, and this groove 7 is not formed in the block 4.5 in FIGS. 3 to 7. Since there is no groove 7, the presence or absence of the groove 7 is free.

(Effects of the Invention) The present invention is as described above, and each of the side blocks 5 has inclined sides 5B and 5C having an inclination angle θ of 30° to 60° with respect to the tire rotation axis XX in the rotation direction. Y, and the total length of the inclined sides 5B and 5C is 0.25 to 0.8 times the total peripheral length of the side block 5. Therefore, it is possible to increase the ground gripping force when turning, which not only improves turning performance significantly, but also provides excellent straight-line safety. It is very profitable as a built-in tire.

[Brief explanation of the drawing]

The drawings show an embodiment of the present invention; FIG. 1 is a front view of a tire, FIGS. 2 to 7 are plan views showing examples of block arrangement patterns, and FIG. 8 is a diagram showing turning performance and inclination angle. FIG. 9 is a graph showing turning performance and slope side length ratio, and FIG. 10 is a graph showing straight running safety and slope side length ratio. 1... Tire, 2... Tread, 4... Center block, 5... Side block. Patent Applicant: Otsu Tire Co., Ltd. Figure 7 Figure 8 Figure 8 Figure 8 Figure 8 Figure 8 Figure 4

Claims (1)

[Claims] (1) A tread located in the center is connected to both sidewalls in a toroidal manner, and on the circumference of the tread, a central block located on the equator line and side blocks located symmetrically on both left and right sides of the equator line are arranged around the tread. In a tire arranged in a herringbone pattern in a protruding direction, each of the side blocks 5 has inclined sides 5B and 5C having an inclination angle θ of 30° to 60° with respect to the tire rotation axis XX. It is characterized by having the inclined sides 5B and 5C at the front and rear in the rotation direction Y, and the total length of the inclined sides 5B and 5C is 0.25 to 0.8 times the total peripheral length of the side block 5. Pneumatic tires for vehicles traveling on rough terrain.