JPS6348721B2 - - Google Patents

Description

[Detailed description of the invention]

The present invention relates to a rubber tire for agricultural machinery that is used at zero or very low internal pressure and is used in agricultural machinery such as rice and wheat reaping and binding machines, which are commonly referred to as binders. Conventionally, this type of tire was pneumatic (with internal pressure).
Tires used to be the most common type of tires, but due to their poor performance in wet paddy fields, in recent years, tires that can be used with zero internal pressure, which have a larger ground contact area and lower ground pressure, and can improve wet paddy performance, have been attracting attention. However, even if these tires with zero internal pressure can achieve the desired wet paddy performance in wet paddy fields, the machine fluctuates greatly when moving binders, etc. to wet paddy fields, and especially when traveling on contour lines on slopes, The machine has the disadvantage of slipping down on the surface and becoming unable to run, which means that it may fall into the field when running on a ridge, which is a serious defect. For example, the conventional tire 26 (Jikkosho 55
34086), it is possible to run on flat ground without any problems, but when running on a contour line on a slope as shown in FIG. 7B, the lateral rigidity is weak and the vehicle slides down the slope. As a result, the aircraft was unable to travel on contour lines. In tests conducted by the present inventors, it was impossible to run on a contour line on a slope with an inclination angle of 10°, and it was impossible to make a U-turn from downhill to uphill on a slope with an inclination angle of 5°.
Note that FIG. 7A shows the state when no load is applied. In addition, the conventional tire 27 shown in FIG.
In the same way as described above, in the case of Japanese Patent Publication No. 97904, a lateral load is applied when running on an inclined surface, so that the lower rim flange becomes outside of the sidewall part and causes lateral slippage, making it impossible to run. FIG. 8A shows the state under no load. In view of these problems with conventional tires, the present invention has developed a tire with a substantially octagonal outer contour to increase lateral rigidity while maintaining good wet paddy performance, and to reduce internal pressure to zero, making it possible to run on slopes. Another object of the present invention is to provide a rubber tire for agricultural machinery that is used at extremely low pressure. A feature of the present invention to achieve this object is that the substantially flat outer contour of the tire has a substantially flat crown portion 3 and an angle of 20 to 60 degrees from both ends of the crown portion 3 in the radially inward direction and the width outward direction. A substantially planar shoulder portion 4 extending at an angle; a sidewall portion 5 extending radially inward from the outer end of each shoulder portion 4 to form the maximum width of the tire; It is formed by a bead portion 6 extending from the end at an angle of 15 to 60 degrees in the radial direction and width direction, and the overall outer contour including the imaginary surface 14 connecting the radially inner ends of both bead portions 6 is approximately 80 degrees. The lugs 2, which are angular and projecting from the crown portion 3, extend to approximately the outer ends in the width direction of the left and right shoulder portions 4. Incidentally, the term "substantially outer cross-sectional contour shape of the tire" as used in the present invention means a smooth outer shape excluding lugs. Embodiments of the present invention will be described below with reference to the drawings. In the first embodiment of the present invention shown in FIGS. 1 to 4, a rubber tire 1 before rim assembly includes lugs 2,
It is composed of a crown part 3, both shoulder parts 4, both side wall parts 5, and both bead parts 6, and the whole is made of rubber (including an elastic material with the same effect as rubber), and the internal pressure is zero or about 0.2 kg. Used at extremely low pressures below / ^cm2 . The outer surface 3a of the crown portion 3 is substantially flat in the tire width direction and circular in the circumferential direction, and a large number of lugs 2 are provided protruding from the outer surface 3a. The lugs 2 are inclined so as to intersect with the center portion 8 of the crown portion 3 and are arranged in a staggered manner. The crown part 3 has a thick wall thickness t8 of the center part 8 and a wall thickness t9 of the lug forming part 9 (thickness of the crown part 3), and is set to a thickness that prevents the lug 2 from wobbling. The part surrounded by the center part 8 and the shoulder part 4 is the center part 8 and the lug forming part 9.
The thin wall portion 10 is thinner and bulges in the radial outward direction, and the wall thickness t10 is 0.2≦t10/t8≦0.5.
It is preferable that This thin wall portion 10 traps soil when touching the ground and removes soil when leaving the ground, increasing the buoyancy effect and the soil removal effect, and also prevents deformation such that the slanted lug 2 approaches parallel to the axis of the tire 1. It is also possible to increase the driving force by allowing this. The shoulder portion 4 extends from both ends of the crown portion 3 in the radially inward direction and the width outward direction at an angle α, forming a planar inclined surface, and the angle α is 20~
60°, and 30-45° is optimal. The outer end of the lug 2 in the tire width direction extends to approximately the outer end of the shoulder portion 4 (the boundary with the sidewall portion 5). A sidewall portion 5 extends radially inward from the outer end of each shoulder portion 4, and this sidewall portion 5 is planar and forms the maximum width T of the tire 1. Further, from the shoulder portion 4 to the sidewall portion 5, lug forming portions 9 are formed on the inner surface thereof.
An inner shape retaining rib 11 is formed at an extended position directly below the lug 2. By locally reinforcing the shoulder portion 4 and the sidewall portion 5 at the portions corresponding to the lugs 2 in this manner, the support strength of the lugs 2 is increased, and maneuverability and steering performance are stabilized and smoothed. be able to. A bead portion 6 extends from the radially inner end of each sidewall portion 5 in the radially inward direction and widthwise direction at an inclination angle β, and the outer surface of the inner end portion serves as the rim mounting surface 12, and the inner end A bead reinforcement engagement recess 13 is formed on the partial outer peripheral surface. The inclination angle β is 15
~60°, 20-45° is optimal. From the bottom of the sidewall portion 5 to the bead portion 6
The entire length in the circumferential direction has approximately the same wall thickness as the inner shape retaining rib 11, and is a rigid body with sufficient strength. The shoulder portion 4 is thinner than the sidewall portion 5, the lug forming portion 9 of the crown portion 3 is thinner, and the wall becomes thicker and more rigid as it goes from the crown portion 3 to the bead portion 6. . Assuming an imaginary surface 14 connecting both bead portions 6, the actual tire outer contour shape consisting of the crown portion 3, both shoulder portions 4, both sidewall portions 5, both bead portions 6, and the imaginary surface 14 is approximately octagonal. In particular, the cross-sectional shape of both sides of the tire 1 is horizontally trapezoidal, so that the lateral and longitudinal rigidities are high. Figure 4A shows the tire 1 with an internal pressure of 0 to 0.2 kg/ ^cm2 when no load is applied, and when driving on a flat road or in a wet field, it is compressed and deformed in the radial direction due to the load of the machine as shown in Figure 4B. On a hard road, only the lug 2 makes contact with the ground, and the load is transmitted to the lug 2, crown part 3, shoulder part 4, sidewall part 5, and bead part 6. In a wet field, the lug 2 gets into the mud and the crown The entire part 3 is also deformed by the load so that the inclination angles α and β, especially the inclination angle α, become small, and the lug 2 is in contact with the ground almost uniformly over its entire length, so the wet field performance is good and the driving force is sufficient. The buoyancy and soil removal effect of the thin wall portion 10 are also effective. FIG. 4C shows the state when running on a slope. Both sides of the tire 1 are always on the outside of the rim 15, and because the lateral rigidity is large, the rim 15 does not shift in the width direction from the crown part 3. Since the bead portion 6 does not come into contact with the inner surface of the crown portion 3, the machine can run without causing fluctuation. In the first embodiment, the shoulder portion 4 and the bead portion 6 are formed flat, but they may be slightly uneven, and the longer the bead portion 6 is to a certain extent, the greater the lateral rigidity of the tire 1 becomes. do. In a second embodiment of the present invention shown in FIGS. 5 and 6, this tire 21 has a planar shape of lugs 22,
The shoulder portion 24 and the sidewall portion 23 are the first
This is different from those in the example. The lug 22 is formed from the center part 8 to the shoulder part 4, and is inclined so that the center part 8 side leads, and the midway part is curved in a concave shape with respect to the rotation direction, so that the driving force can be further increased. It's getting old. In addition, the sidewall portion 23 is a circular arc wall with a large diameter curvature that bulges outward in the width direction, and has no shape-retaining ribs on the inner surface, and is thick with approximately the same thickness from the upper end to the lower end. The bead portion 6 is also thicker than the shoulder portion 4, making it easier to deform under load and further increasing the lateral rigidity in the widthwise direction. It is configured to more reliably prevent lateral displacement. The following table shows test examples of tires 1 and 21 shown in the first and second embodiments.

【table】

[Table] Three tires 1, 1', and 21 were mounted on a binder and subjected to a contour running test on an inclined surface with an angle of inclination of 10°.
As a result of performing a U-turn test on an inclined surface with an inclination angle of 5°, there was no fluctuation or slippage of the binder at all.
Stable running is possible, sidewall parts 5, 23
There was no phenomenon in which the rim went inside the rim 15 at all. According to the present invention described in detail above, since the tire cross-sectional outer contour shape is substantially octagonal, when the tire is under the load of the machine, the central position of each part curves into an arc before it curves. In addition, the corners between each part are bent and stretched, and in particular, since the shoulder part 4 has a substantially planar shape, the corner with the crown part 3 is stretched, and the corner with the sidewall part 5 is bent. ,
The sidewall portion 5 has an expanded shape that is strongly pushed outward in the tire width direction from the shoulder portion 4 and the bead portion 6, so that even when driving on a contour line on a slope or making a U-turn, the sidewall portion 5 remains in the shoulder portion 4 and the bead portion 6. 5 is maintained outward in the width direction, and the corners of the bead portion 6 and sidewall portion 5 are bent to accommodate the inclination, so that the movement of the machine in the tire width direction is maintained. This prevents the machine from fluctuating or slipping.
Furthermore, since the lugs 2 extend not only to the crown portion 3 but also to approximately the outer ends in the width direction of the left and right shoulder portions 4, the corners between the shoulder portions 4 and the crown portion 3 are exposed to the load of the machine. When the outer end of the shoulder portion 4 in the width direction approaches the ground due to expansion, the outer end of the lug 2 will be strongly pressed against the ground, and especially on slopes, the upper outer end of the lug will be the lower outer end of the lug. The outer edge of the lug is pressed harder than the edge, giving it a good grip with the ground and preventing the tire from slipping off.
This serves as a reinforcing portion that maintains the planar shape of the shoulder portion 4 and prevents bending of the corner portion with the crown portion 3.
A strong force is generated to push the sidewall portion 5 outward in the width direction of the tire, thereby increasing the effect of preventing the machine from wobbling or slipping.

[Brief explanation of the drawing]

1 to 4 show a first embodiment of the present invention, in which FIG. 1 is a cross-sectional view, FIG. 2 is a plan view, FIG. 3 is a sectional view taken along the line of FIG. 2, and FIG. A, B, C
are explanatory diagrams showing the conditions of the tire when it is unloaded, when it is loaded on flat land, and when it is loaded on slope, respectively. Figures 5 and 6 show the second embodiment of the present invention, and Figure 5 is a cross-sectional view. , Figure 6 is a plan view, Figures 7 and 8 show conventional examples, Figures 7A and 8A are when no load is applied, and Figures 7B and 8B are when loaded on a slope. FIG. 1... Rubber tire, 2... Lug, 3... Crown part, 4... Shoulder part, 5... Side wall part, 6... Bead part, 15... Rim, 21... Tire, α... Angle, β...Angle.

Claims (1)

[Claims] 1 The actual cross-sectional outer contour shape of the tire is formed by a substantially flat crown portion 3 and from both ends of the crown portion 3 in the radially inward direction and the width outward direction.
A substantially planar shoulder portion 4 extending at an angle of 20 to 60 degrees, a sidewall portion 5 extending radially inward from the outer end of each shoulder portion 4 to form the maximum width of the tire; A bead portion 6 extends from the radially inner end of the sidewall portion 5 at an angle of 15 to 60 degrees in the radially inner direction and widthwise direction, and an imaginary surface 14 connecting the radially inner ends of both bead portions 6 is formed. The internal pressure is zero or extremely low, and the entire outer contour including the angular shape is approximately octagonal, and the lugs 2 protruding from the crown portion 3 extend to approximately the outer ends in the width direction of the left and right shoulder portions 4. Rubber tires for agricultural machinery used at low pressure.