JPH0433641B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to improvements in ultra-low pressure tires mounted on the wheels of vehicles for running on rough terrain.

BACKGROUND ART For vehicles such as buggy-type motorized tricycles and four-wheeled vehicles that travel on soft surfaces such as sandy, muddy, and snowy roads, ultra-low pressure tires called balloon tires are mounted on the wheels. The ultra-low pressure tire is filled with extremely low air pressure and has a block-shaped protrusion formed by its tread pattern, that is, as shown in FIG. 7, the tread 121 has blocks 122 for ground resistance... The ultra-low pressure tire 120 provided with the above is attached to the wheel rim 111.

When this ultra-low pressure tire 120 is run on a soft surface such as a sandy ground, muddy ground, snowy road, etc., as shown in FIG.
... occurs, and the protrusion 142... occurs between the front and back of the recess 141...
However, the protrusion 1 remaining on the tread of the soft surface 140 due to the rotation of the tire 120 (counterclockwise in the illustration)
42 easily collapse from the base due to the blocks 122 of the tire 120, which sometimes caused a loss in the transmission of driving force.

Here, the reason why the protrusion 142 is likely to collapse from the base is because
It is believed that the strength is insufficient due to insufficient compaction action on the top portion 142a.

Therefore, the purpose of the present invention is to effectively compact the protrusion marks left on the soft surface due to running and increase the density, thereby making it difficult to collapse from the base. An object of the present invention is to provide an ultra-low pressure tire that can improve resistance and improve transmission of driving force.

In order to solve the above problems, the present invention provides an ultra-low pressure tire that is attached to the wheels of a vehicle for traveling on rough terrain, is filled with extremely low air pressure, and has a block-shaped protrusion formed in a tread pattern. A protrusion is provided between the front and rear of the block-shaped protrusion, which is lower than the block-shaped protrusion and compresses protrusion marks left between the front and rear of the recess marks caused by the block-shaped protrusion on a soft road surface. It is characterized by

Preferred embodiments of the present invention will be described in detail below with reference to the accompanying drawings.

Figure 1 is an external perspective view of a buggy type vehicle.
Although a three-wheeled motor vehicle is shown in the embodiment, the present invention is of course also applicable to a four-wheeled motor vehicle.

As shown in the figure, an internal combustion engine 3 is mounted within a body frame 2 of a tricycle 1, a fuel tank 4 and a seat 5 are placed on the frame 2 in order from the front, and left and right steps 6 are placed on the bottom of the frame 2. , 6 are provided to protrude sideways. A front wheel 9 is pivotally supported at the lower end of front forks 8, 8, which are supported for steering operation together with a bar handle 7 at the front of the frame 2, and a rear fork (not shown) is pivotally supported at the rear of the frame 2. An axle shaft for the two rear wheels 10, 10 is pivotally supported at the rear end, and a power transmission mechanism such as a chain sprocket mechanism is installed between the axle shaft and the output shaft of the engine 3. , 10 constitute driving wheels.

First, the ultra-low pressure tire 20 of the present invention has a block-shaped protrusion formed by the tread pattern (hereinafter simply referred to as a block) between the circumferential areas.
A protrusion lower than that is provided.

Front wheels 9 and rear wheels 10, 1 of such a tricycle 1
The ultra-low pressure tire 20 of the present invention is mounted on the vehicle.

That is, as shown in FIG. 2 showing the tire pattern, approximately inverted V-shaped blocks 22 are provided at equal intervals radially in the center of the tread portion 21 of the ultra-low pressure tire 20. Hexagonal blocks 23..., 23... are provided on the V-shaped expansion tip side, and approximately V-shaped blocks 23...
Square blocks 24..., 24... are provided, and hexagonal blocks 25..., 25... are provided on both sides of these blocks 24... and outside of the V-shaped expansion tip, and further Approximately inverted V-shaped blocks 26, 26, .

Thus, the tread portion 21 is provided with square blocks 22, 23, 2 so as to form two V-shapes in the width direction.
4 are provided protrudingly at equal intervals over the circumferential direction.
In addition, relief mechanisms 22a, 24a, and 26a are recessed in the V-square blocks 22, 24, and 26.

In this embodiment, the two V-shaped square blocks 22, 23, 2 of the tread portion 21 are
Similarly, two series of V-shaped protrusions 27 are continuously formed in the width direction between the circumferential direction of the 4..., that is, between the front and back. This protrusion 27 is sufficiently lower than the protrusion and is formed in a band shape extending between the V-shaped blocks 26 on both outer sides of the tread portion 21.

Also, the corner portions 27b, 27c, 2 of this band-shaped protrusion 27
7d and both end portions 27e and 27f are formed wide in the circumferential direction.

Note that ring-shaped protrusions 32, 32 are provided on both shoulder portions 31, 31 of the tire 20, and both protrusions 3
2, 32 toward the tread portion 21.
..., 33... are provided, and the protrusions 33, 33 on both sides face the outside of the band-like protrusion 27.

Next, the operation of the ultra-low pressure tire 20 described above will be explained.

As shown in FIG. 3, which is based on the cross section of FIG. ... occurs, and the recess 41...
A protrusion 42 remains between the front and rear of the tire, and although the protrusion 42 tends to be softer than a high-pressure tire, the top of the protrusion 42 is formed into a small recess 47 by the band-like protrusion 27 provided on the tire 20. Because it is compressed as
As shown in FIG. 4, the protrusions 42 remaining on the soft surface 40 are further compacted by the small recesses 47 due to the compressive action of the belt-shaped protrusions 27 of the tire 20, so that their density becomes approximately circular. Increase like 43.

In this way, the protrusions 42 remaining on the tire tread of the soft surface 40 are further trodden by the small recesses 47 by the band-like protrusions 27 provided between the front and rear blocks 22 of the tire 20, so that the soft The protrusions 42... of the surface 40 are further compacted by the tire protrusions 27..., and due to the reinforcing effect of increasing the density like the substantially circular part 43, the root part of the protrusions 42... is caused by the rotation of the tire 20 (counterclockwise in the illustration). This makes it difficult for the front shoulder portion 44 to collapse.
Therefore, the ground resistance due to the blocks 22 provided on the tire 20 is improved, and the transmission of driving force is improved.

In the above, the longitudinal width L of the upper surface 45 of the protrusion 42 remaining on the soft surface 40, that is, the block 2 of the tire 20
2... and the longitudinal width l of the upper surface 27a of the strip-shaped protrusion 27 of the tire 20 (L≒2l), that is, the longitudinal width l of the strip-shaped protrusion 27 is an abbreviation of the longitudinal spacing L of the blocks 22... When it was halved, good grounding resistance was obtained.

3 and 4 are projections formed on the tread surface of the soft surface 40 by relief grooves 22a formed in the blocks 22 of the tire 20.

Incidentally, in the above embodiment, a band-like protrusion that is continuous in the width direction of the tire is provided between the front and rear of the tire block, but as in the modified embodiment shown in FIGS. 5 and 6, a discontinuous protrusion is provided. Also good.

As shown in the figure, the tire pattern of this modified example has rectangular square blocks 28 arranged in a houndstooth pattern, and square protrusions that are lower than the blocks and are also rectangular between the front and rear of the blocks 28. Section 29... is provided. In this case, the horizontal width of the square protrusion 29 is approximately equal to or greater than that of the block 28.

Such discontinuous square protrusions 29 can also provide the same effects as described above.

The heights of the band-like protrusions 27 and the square protrusions 29 are set to a necessary and sufficient level so that the protrusions 42 remaining on the weak surface 40 are compressed and compacted to increase their density, thereby making them difficult to collapse from the base. That's fine.

As is clear from the above description, according to the ultra-low pressure tire of the present invention, a lower protrusion is provided between the front and rear of the block-shaped protrusion formed by the tread pattern, and this protrusion allows This method compresses and compacts the protrusion marks left between the front and back of concave marks caused by block-shaped protrusions on soft road surfaces such as sandy, muddy, and snowy roads, increasing the density of the protrusion marks and reinforcing them. Since it is possible to prevent collapse from the root and prevent collapse of only the shoulders, collapse of the tread can be stopped to the extent that it does not affect the ground resistance of the tire, thus improving the driving force transmission of vehicles running on rough terrain. improvement can be achieved.

[Brief explanation of drawings]

Fig. 1 is an external perspective view of an off-road vehicle to which the present invention is applied, Fig. 2 is a partial plan view of a tire pattern, and Fig. 3 is a cross section showing the effect of the present invention based on the line in Fig. 2. Figure 4 is a sectional view showing an enlarged view of the tire tread surface on the soft side, Figure 5 is a partial plan view showing an example of changing the tire pattern, Figure 6 is a sectional view taken along the line 5 - Figure 7. FIG. 8 is a perspective view of a conventional ultra-low pressure tire, and a sectional view showing its function. In the drawing, 1 is a vehicle for traveling on rough terrain, 20 is an ultra-low pressure tire, 22, 23, 24... are blocks, 27,
29... is a protrusion, 40 is a soft surface, and 42... is a protrusion remaining on the tire tread.

Claims (1)

[Claims] 1. In an ultra-low pressure tire that is attached to a wheel of a vehicle for traveling on rough terrain and is filled with extremely low air pressure and has a block-shaped protrusion formed in a tread pattern, there is a tire between the front and rear of the block-shaped protrusion. An ultra-low pressure tire, characterized in that a protrusion is provided that is lower than the block-shaped protrusion and compresses a protrusion mark left between front and back of a recess mark caused by the block-shaped protrusion on a soft road surface.