JPS58152604A - Running tire for irregular ground - Google Patents

Abstract

PURPOSE:To contrive an increase of a contact area with the ground, by providing a rigidity interrupting groove having a predetermined tilting angle against a circumferential direction of a tire and a predetermined depth in the middle of a longitudinal direction of a lug, in a very low internal pressure tire for the soft ground running on an irregular ground. CONSTITUTION:A rigidity interrupting groove 8 having a tilting angle (d) of 30-90 deg. against a circumferential direction of a tire and a depth (h) of at least one third of a height H of a lug 6 is formed in the middle of a longitudinal direction of the lug 6. A groove width (i) is made so as to fall within a range of 0-10mm. when cutting in of the groove is in such construction that does not cut out rubber, and a number of gooves 8, the depth (h), the width (i) and the tilting angle alpha are set within a range of possibility of alleviation of flexural rigidity of a tread 2 without spoiling an original function of the lug 6. With this, the function of the lug 6 is secured, bending resistance of the tread during running is reduced and an increase of a contact area with the ground can be contrived.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a tire for running on rough terrain, and a tire for soft terrain to which an extremely low internal pressure of 0 to 1 (-%) is applied.

Agricultural vehicles, construction vehicles, and transport single-purpose tires, which are mainly used on rough terrain other than roads, and on weak terrain, have lugs to improve the necessary traction force and trendy mud clearance when driving or working. type of tread is preferred. As it is widely known, it is a lug type tread.

Bar-shaped lugs extending from the center of the tread to both ends of the tread are inclined at a front edge of 40° with respect to one circumferential direction and arranged in a herringbone pattern toward the center.

When trying to obtain a large traction force without impairing mud drainage, it is effective to increase the ground contact area.

As a measure for this purpose, increasing the tire outer diameter in terms of tire design,
Increasing tire width or trend width and applying lower internal pressure are possible. Of these, the tire outer diameter and/or tire width cannot be increased excessively when the target vehicle is determined, and this increases the cost, which is not economical. - Although increasing internal pressure is highly feasible because it does not involve high costs, it has traditionally been thought that there is a limit to the increase in ground contact area under the constraints of the outer diameter and width of the tire.

In order to increase the ground contact area, the inventor conducted various studies and achieved nine points.
According to the research, it was found that #4 diagonally arranged lugs, which are not a problem in tires that are used for relatively high internal pressures, are a major factor in reducing W in terms of increase in ground contact area when tires are used for extremely low internal pressures.

The present invention provides a pneumatic tire in which the ground contact area is increased mainly by applying rigidity reducing means to the lugs that inhibit the increase in the ground contact area. The above trend is for tires in which the sidewalls are connected in a toroidal manner from both ends, and lugs extending from the center to each end at an angle with respect to the circumferential direction protrude in a herringbone pattern. There is a range Vc with an axis oblique angle of 30 to 90 degrees, and the depth is at least the same as the lug height 2
) It is recommended to install a tool 7 in the middle of the rigid continuous groove in the longitudinal direction.
The second aspect of the present invention is a pneumatic tie tag for running on rough terrain, and the second aspect of the present invention is that a ring trend located in the center and sidewalls are connected from both ends of the trend in a toroidal shape, and the trend is connected from the center to each end. In a tire having a herringbone pattern extending obliquely to the local direction, the lug has an inclination angle of 30 to 90° with respect to the local direction, and the lug height is at least h.
% of the total gauge of that part on the red pace.
This pneumatic tire for running on rough terrain is characterized by having lateral grooves with a depth not exceeding 50 inches over a trend width of at least 50 inches.

This will be explained below based on the drawings.

FIG. 1 is a partial perspective view of a tire according to the present invention. In the figure, a tire 1 consists of an annular tread 2 located in the center and a pair of sidewalls 5 extending in a loid shape at both ends of the tread. Tire I at main departure 1q
Since extremely low internal pressure (internal pressure 0 to 1 (-)) is applied, it is desirable to have a structure suitable for this and to form only the actual rubber, except for the bead wire 5 buried at the tip of the heating part. However, Unless it deviates from the purpose of the present invention, a radial carcass emitted from the KMI fiber or ri metal hood layer between two bead wires, and a belt layer superimposed on the crown portion of the carcass.
Such as a structure in which a scarf and a play car are layered in the same way,
It is also possible to use known reinforcement means.

Tread 2 runs from the center of the trend, that is, from the equator 0-0, to the trend j [i! Lugs 6 extending toward each end were protruded from the trend base 7 in one direction (at an angle of about 1109). This is the so-called lug type. In this embodiment, the lugs 6ri are arranged alternately on the left and right in the circumferential direction, forming a herringbone pattern as a whole.

Each of the lugs 6 is provided with a rigid connecting groove 8 in the middle of the longitudinal direction thereof, thereby alleviating the resistance of the lower wall against bending deformation in the circumferential direction of the tread during running of the tire. Groove depth ha Lug height H at least b (in the example shown, riH = hLw Width 1 is in the case of a cut that does not cut out rubber, that is, it is set in the range of 0 to 10 haze, impairing the circumferential (equatorial) direction ability. First, in accordance with the purpose of the present invention, which is to reduce the bending stiffness of the tread, depending on the use of the tire.

It shall be selected as appropriate within the above numerical range.

FIG. 2 is a partial perspective view of a tire showing another embodiment of the present invention.

The feature of this embodiment is that the left and right lugs 6 are joined in a V-shape at the equator 〇-〇 position, and the left and right portions 6-1, 6-2 and 6- of the tread 2 have approximately equal lengths, respectively. This example differs from the example shown in FIG. 1 in that rigid connecting grooves 8-1 and 8-2 are provided at the positions where 3 is divided.

FIG. 5 is a partial perspective view of a tire showing another invention.

The feature of this invention is that a plurality of horizontal sections 1119 are added to the tread pace section 7 on the circumference of the tread. In the example shown in Fig. 5, in order to facilitate bending deformation of most of the tread base part around the equator, G is attached to the original gauge Gt of the pace part.
Thinned almost uniformly by t - G c (Bami Toshisara K
A lateral groove 9 is provided between Gc and Gt. The lateral groove 9 is continuous for a length Lg of at least 30% of the tread width Wt.

Regardless of whether it is interrupted or not, the depth of the horizontal groove is the overall gauge G of that part.
tf) shall not exceed %. On the other hand, the width j of the lateral groove 4 is considered to be from 0 to the entire trend pace portion between the local direction lags. Therefore, although it is not necessarily necessary to use the horizontal grooves and depressions in combination, in the case of the example shown in Figure #I5, the arrangement relationships in Figures 1 and 2 are applied to the lugs 6 and the rigid continuous grooves 8, respectively, but the horizontal grooves 9 When a relatively narrow groove is used as a groove, it is desirable to associate it with the stiffness cutoff groove 8 of the lug in terms of its arrangement position.

In order to check the ground contact characteristics of the tires made during this 5K, we made a prototype tire size 18X'1O-8 and installed it on a rice and wheat harvesting and binding machine. Tested. Internal pressure is 0 as test condition
．． '#Heavy#' One 180V tire. In addition, regarding the structure, the tire uses only rubber without a cord layer such as a carcass, and the lug arrangement is the same as shown in Figure 1, with rigid continuous grooves 8-1 and 8-2 provided on each lug. A, groove 8-1. In addition to g-2, a tire with lateral grooves 9 provided at each of these groove positions (Gc=, 01) is designated as B and groove 8.
．． Conventional knee without 9) 4. tya was set as C. The detailed specifications of these test tires are shown in Table 91, and the test results are shown in Table IR2.

Note in Table 2) The value in LO is an index of 2 when the value of tire C is taken as 100, and the value of running limit soft ground indicates the depth to which a person's foot sinks in the field.

As shown in Table 2, tires B and B, which are inferior to the present invention, both have a shorter contact length than the conventional tire C due to the stiffness connection of the lugs and the effect of softening the bending stiffness based on the trend. It can be seen that there is an increase in the ground contact area and a corresponding increase in the ground contact area, and as a result, the degree of soft ground that is the driving limit has greatly improved. On the other hand, this increase in contact length means that the number of lugs included in the contact surface increases, which has an advantageous effect on the traction force of the vehicle.

[Brief explanation of the drawing]

FIG. 1 is a partial perspective view of a tire according to the present invention. FIG. 2 is a partial perspective view of a tire showing another embodiment of the invention.
・・Tire 2・・・Trend La・・・Sidewall 6・・・・Lug
7・-・・・・）l/,/piece t...Rigid connecting groove 9...lateral groove Patent originator: Brideston Tire Co., Ltd. Representative Patent Attorney Hide Kume - Same patent attorney
Etsu Suzuki Department Figure 2

Claims (4)

[Claims] (1) An annular tread located in the center and sidewalls extending from both ends of the tread in a toluid shape,
The above trend is for tires that have lugs that run from the center to each end at an angle to the local direction and project in a herringbone pattern. The above lug has an inclination angle of 50 to 90 with respect to the local direction of the tire.
'No range #! 4. A rigid continuous groove having a depth of at least H of the lug height is provided in the middle of the longitudinal direction.
IIIk pneumatic tire for driving on rough terrain. (2) The tire for running on rough terrain according to claim 1, wherein the width of the rigid continuous groove is in the range of 0%1011111. (3) Divide the length of the two rigid continuous grooves into equal parts. The tire for running on rough terrain according to claim 1 or 2, characterized in that the tire is provided at a certain position. (4) Sidewalls are connected in a toluid shape from both ends of the annular trend and mosquito trend located in the center,
In the tire, the tread has lugs projecting from the center to each end at an angle with respect to the center direction. The angle of inclination of the above lugs to the circumferential direction of the tire is 30 to 90.
A rigid continuous groove with a lug height of at least h/)9 is installed in the middle of the longitudinal direction, and a groove with a depth not exceeding h of the overall gauge of that part is installed in the trend pace part. A tire for running on rough terrain that has multiple lateral grooves or depressions extending at least 0 inches beyond the trend width.