JPH01257604A - Pneumatic tyre for farming operation - Google Patents

Abstract

PURPOSE:To decrease earthing surface pressure by means of the increase of earthing area of the title tyre and also contrive improvement of running linearity and the restraint of pitching thereof by slanting a tread part in one direction and also making the rigidity of a right/left pair of side wall parts higher or lower from each other. CONSTITUTION:A pneumatic tyre 10 is provided with a right/left pair of bead parts 11, 12, side wall parts 13, 14 and shoulder parts 15, 16 and also respective shoulder parts 15, 16 are connected together by interposing a tread part 17 therebetween. In this case, the pneumatic tyre 10 is formed laterally asymmetrical with respect to the center line thereof, namely a meridian O-O. The tread part 17 is slanted in one direction from one shoulder part 16 toward the other shoulder part 15 and is also formed with the shape along the slant surface 18 of a levee. In respective side wall parts 13, 14, the rigidity of the side 13 on levee side thereof is made low, while the rigidity of the side 14 on the counter levee side thereof is made high. Thereby, the damage of the levee and the stagger to the right and left sides can be prevented and then this tyre is made suitable for a transplanting machine and the like.

Description

DETAILED DESCRIPTION OF THE INVENTION (Industrial Field of Application) The present invention relates to a pneumatic tire for agricultural work, and is used for a vehicle that travels between furrows for transplanting work and the like.

(Prior Art) Generally, the cross-sectional shape of the pneumatic tire 1 is determined by its center line (
It has a symmetrical shape with respect to the meridian line) 0-0,
12, the rigidity of the sidewall parts 2 and 3 is the same on the left and right,
It bends almost uniformly under load (see Figure 4).

(Problems to be Solved by the Invention) By the way, as shown in FIG. In particular, since the vehicle runs only on the ground contact side shoulder portion 4, and the ground contact area L1 is narrow, the contact surface pressure is high and may cause the ridge to collapse or the mulch film to break.

Therefore, in order to increase the ground contact area, it is sufficient to lower the tire rigidity, but this lowers the lateral rigidity, causing the vehicle to flutter from side to side, and worsening straight-line performance.

The tire disclosed in JP-A-61-275008 is similar to the present invention only in that the tread shape is distorted.

The present invention makes the cross-sectional shape of the tire asymmetrical with respect to the meridian line, and also makes the rigidity of the sidewall portion different on the left and right sides, so that running between ridges is accurate and easy, and there is no ridge collapse. The purpose is to provide a pneumatic tire for agricultural work that can be driven at high speeds.

(Means for Achieving the Object) The present invention provides a pneumatic tire 10 in which a pair of left and right bead portions 11 and 12 are connected to a tread portion 17 via a sidewall portion 13.14 and a shoulder portion 15.16. , has taken the following technical measures to achieve the stated purpose.

That is, the tire 10 of the present invention has its meridian line 0-0
The tread portion 17 is inclined in one direction from one shoulder portion 16 to the other shoulder portion 15, and is shaped to follow the ridge slope elevation surface 18. The parts 13 and 14 are characterized in that the rigidity of the sidewall part 13 of the ridge side 12 is low, and the rigidity of the sidewall part 14 of the ridge side 12 is high.

(Function) As shown in FIG. 2, in the tire 10 of the present invention, the trend portion 17 is in contact with the ridge slope elevation surface 18 from side to side beyond the meridian line 0-0, increasing the ground contact area. The vehicle will run while reducing the ground pressure.

That is, since the tread portion 17 is inclined in one direction from one shoulder portion 16 to the other shoulder portion 15 and has a shape along the ridge slope elevation surface 18, the ground contact area is increased.

At this time, the sidewall parts 13 and 14 are the 12 on the ridge side, the sidewall part 13 has low rigidity, and the sidewall part 14 has high rigidity, and the rigidity of the sidewall part 14 is high. Good conformability and good straightness.

Incidentally, when the tire 10 of the present invention is used as a traveling device for a furrow traveling working vehicle such as a transplanter, both left and right tires are mounted as shown in FIG.

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

In FIG. 1, 10 is a pneumatic tire, which includes a pair of left and right bead portions 11.12, a pair of left and right bead portions 12, a sidewall portion 13.14, and a pair of left and right shoulder portions 15.
16, and the shoulder portion 15.16 has a tread portion 17.
are connected to each other.

This pneumatic tire 10 is mounted on a rim 20 and is used, for example, as a traveling device for a furrow working vehicle with a tire internal pressure of about 0.2 kg/aJ.

Note that examples of the furrow traveling work vehicle include a transplanter, a cultivator, and a thinner.

In addition, bead core IIA, 12
The bead cores IIA and 12A may or may not have a carcass connecting them to each other.

Furthermore, the tread portion 17 has groove lugs, striped lugs, etc. formed in a predetermined pattern.

The tire 10 has an asymmetrical shape with respect to its center line, that is, the meridian line 0-O, and the tread portion 17 is inclined in one direction from one shoulder portion 16 to the other shoulder portion 15. Moreover, as shown in FIG. 2, the shape is along the ridge inclined elevation surface 18.

Here, one shoulder portion 16 is located at a radially outer position of the tire IO, and the other shoulder portion 15 is located at a radially inner position of the tire 10.

This means that the left and right parts 12, the sidewall parts 13.1
The radial length of 4 has long and short lengths, and the rigidity of the ridge side 12 is determined by the rigidity of the sidewall portion 13, and the rigidity of the sidewall portion 13 is determined by the other 12.
The rigidity is lower than that of the sidewall portion 14.

In order to make the rigidity of the sidewall parts 13 and 14 different, it is possible to increase the gauge thickness of the sidewall part 14 as shown by reference numeral 19 in FIG. 3, or to increase the number of carcass reinforcing layers. Increases and decreases, etc. can be mentioned.

Therefore, when the above-mentioned tire 10 is mounted on a transplanting machine and transplanting work is carried out, the tread portion 17 is moved along the ridge slope elevation surface 18 as shown in FIG.
Because the ground contact area has been increased, the surface pressure is low, and work can be done without problems such as breaking the ridges or tearing the mulch film.

Furthermore, this effect is further improved by lowering the rigidity of 12 on the ridge side and the sidewall part 13. Since it is high, straightness is ensured.

Furthermore, since the tread side rigidity can be lowered, pitching vibration caused by soil clods can be reduced, and the planting depth can be made uniform during transplanting work.

(Effect of the invention) The present invention is as described below, and has the following advantages.

The trend section is sloped from one shoulder section to the other shoulder section, and is shaped to follow the ridge slope elevation, so the tire contact pressure is lowered by increasing the ground contact area.
Eliminates ridge collapse, mulch film tearing, etc.

In addition, even if the tire is asymmetrical as described above, the 12
, the rigidity of the sidewall part is low, and 12 on the ridge side,
Since the rigidity of the sidewall portion is made high, it is possible to improve straight running performance and suppress the pitching phenomenon while preventing left-right fluctuation L2.

Therefore, the tire of the present invention is highly useful for agricultural work, especially for use in transplanters.

[Brief explanation of the drawing]

Fig. 1 is a sectional view showing an embodiment of the tire of the present invention, Fig. 2 is a sectional view of the tire in use (driving), Fig. 3 is a sectional view of the second embodiment, and Fig. 4 is a sectional view of a conventional tire. 5 is a sectional view of the device in use. 10...Tire, 11.12...Bead portion, 13.
14...12, side wall part, 15.16...
-Shoulder part, 17...Tread part. Patent applicant Otsukiya Co., Ltd.
5-・1

Claims (1)

[Claims] (1) In a pneumatic tire 10 in which a pair of left and right bead portions 11 and 12 are connected to a tread portion 17 via sidewall portions 13 and 14 and shoulder portions 15 and 16, the tire 10 has a meridian line O The tread portion 17 is slanted in one direction from one shoulder portion 16 to the other shoulder portion 15 and has a shape along the ridge slope elevation 18, and further has a sidewall portion. Reference numerals 13 and 14 refer to pneumatic tires for agricultural work, characterized in that a sidewall portion 13 on the ridge side has low rigidity, and a sidewall portion 14 on the opposite ridge side has high rigidity.