JPS61249806A - Pneumatic lug tire for rough road running - Google Patents

Abstract

PURPOSE:To prevent blocking between lugs and improve straight advanceability in the above-captioned tire having a lug pattern, by arranging each pair of right and left L-shaped lugs, making a longer side of each lug inclined at a fixed angle, and arranging both shorter sides of the right and left lugs in spaced parallel relationship with each other at a central area of a tread surface. CONSTITUTION:Each pair of left and right L-shaped lugs 11 and 12 having longer sides 13 and 14 and shorter sides 15 and 16 are arranged on a tire tread surface 10. The longer sides 13 and 14 of the lugs 11 and 12 extend in opposite directions with respect to a circumference of the tire at an angle of about 45 deg. thereto. End portions 17 and 18 extend from the longer sides 13 and 14 at right angles to the circumference of the tire. The shorter sides 15 and 16 are arranged in parallel relationship with each other by the distance of l1 in a central area of the tread surface in such a manner that they are partially overlapped circumferentially and laterally. With this arrangement, it is possible to prevent blocking between the lugs and improve straight advanceability with a traction performance maintained.

Description

DETAILED DESCRIPTION OF THE INVENTION (Field of Industrial Application) The present invention relates to a pneumatic tire having a lug pattern for running on rough terrain.

(Prior Art) A tread includes a tread surface and a pair of sidewalls, and the tread has a lug pattern in which pairs of lugs each having a substantially identical shape are arranged on the left and right at approximately equal intervals in the circumferential direction. Since pneumatic tires are used for driving on rough terrain, unlike on good roads, they are designed to improve traction performance in the front, rear, left and right directions, and also to prevent mud from clogging the tires. In other words, it is normal to set the negative to a large value and to have a shape in which the lugs are divided on both sides of the tread surface. Such a lug tire has lugs relatively large in height and width, and the left and right lugs are inclined in opposite directions or in the same direction with respect to the circumferential center line of the tread portion, and the left and right lug rows are half-pitch with respect to each other. Structures in which the elements are arranged so as to be offset from each other are conventionally known.

(Problems to be Solved by the Invention) The conventionally known lug tires described above have the following problems. First, in a lug tire in which a pair of left and right lugs are arranged so as to be inclined in opposite directions with respect to the circumferential center line of the tread, the lug pattern has directionality, so there is a certain It can only be used in the direction of rotation,
As a result, tire position replacement is restricted. In general, tires have different wear conditions depending on where they are used, and it is considered essential to use tires to maintain uniform characteristics over a long period of time. Being restricted is inconvenient. In addition, in lug tires in which the left and right lugs in a pair are arranged inclined in the same direction with respect to the circumferential center line of the tread, the lug pattern has no directionality and can be used in both rotational directions. Although it is possible to freely exchange positions, the lugs tend to deflect in a certain direction during rotation due to the fact that all the lugs form a pattern that slopes only in a certain direction over the entire circumference of the tire. , it is hard to say that it has excellent straightness.

Therefore, the present invention can maintain sufficient traction performance in the front, rear, left, and right directions when driving on rough terrain, can prevent mud from clogging between the lugs, and has excellent straight-line performance.
The purpose of this project is to propose a lug tire whose position can be freely exchanged.

(Means for Solving the Problems) To achieve the above purpose: As a result of intensive study by the inventor, it was found that the lug tread was designed to improve traction performance in the front, rear, left and right directions, prevent mud jams, and ensure freedom of position exchange. It has been found that a lug pattern is basically required in which the lug pairs are divided at the tread portion and arranged in pairs on the left and right, with each pair of lugs being arranged at an angle with respect to the circumferential direction of the tire. In addition, in order to eliminate the deflection that was conventionally thought to be unavoidable in such arranged lug patterns and ensure straight running, it is necessary to create a component in the shape of the lug itself that cancels the deflection caused by the lug pattern. It was also found that it was necessary to provide this.

The present invention has been made based on the above idea, and includes a tread surface portion and a pair of sidewall portions, and a pair of lugs in which a pair of lugs of approximately the same shape are arranged on the left and right sides of the tread surface portion in the circumferential direction. In a pneumatic tire for running on rough terrain having a lug pattern arranged at approximately equal intervals, each of the lugs has a long side and a short side that are inclined in opposite directions with respect to the circumferential direction, so that the long side and short side thereof have a substantially slanted shape. The left and right lugs of the pair of lugs are formed so that the short sides thereof are parallel to each other and spaced apart from each other in the central region of the tread portion, and at least partially mutually in the circumferential and transverse directions. The treads overlap each other, and are arranged so that the long sides extend in opposite directions from the central region to both side regions of the tread portion at a substantially constant inclination angle with respect to the circumferential direction.

(Operations and preferred embodiments) In the present invention, the short sides of the rugs having a substantially slanted shape are spaced parallel to each other in the central region of the tread surface,
Arranging the lugs with the long sides inclined in the opposite direction to the short sides is an important configuration in order to cancel out the deflection that occurs during running in this type of lug pattern and ensure straight running. be. Furthermore, arranging the short sides of the lugs in the central region of the tread portion so as to overlap each other at least partially when viewed in the circumferential and transverse directions improves ride comfort, reduces vibration, and improves straight-line performance. This is because it becomes possible.

In a preferred embodiment of the present invention, the left and right lugs of each pair of lugs are arranged symmetrically with respect to a symmetrical point on the circumferential center line of the tread portion. According to such a configuration, since the tread pattern has no directionality, there is an advantage that the position of the tire can be changed freely.

In another preferred embodiment of the present invention, the longitudinal traction performance is improved by extending the terminal portions of the long sides of the lugs disposed on both sides of the tread portion substantially in the transverse direction. The length of this terminal portion is desirably set within a range of about 15 to 30% of the ground contact width of the tread portion.

In order to more effectively eliminate the deflection during running due to the lug pattern, it is advantageous for the short and long sides of each lug to be inclined at approximately equal angles to the circumferential direction, preferably at approximately 45°. It is. Further, it is desirable that the length of the long side excluding the terminal portion is approximately equal to the length of the short side.

Furthermore, in order to properly prevent mud from clogging between the lugs, the distance between the short sides of the left and right lugs that are spaced apart from each other in the central area of the tread is within a range of about 1.0 to 2.0 times the width of the short sides. , preferably about 1.5 times.

(Example) Hereinafter, the present invention will be described with reference to illustrated embodiments.

FIG. 1 shows the present invention in tire size 22X10. OO-10
An example of application to a pneumatic relag tire for running on rough terrain with ゜10PR and internal pressure of 4.6 kg/cm'' is shown.
This tire is made of 1260d/2 nylon cords arranged at an angle of 35° to the circumferential direction.
It has two carcass layers stacked one on top of the other so as to extend in opposite directions. Furthermore, to prevent cuts, two breaker layers made of a 1×5 structure of steel cords are arranged on the radially outer side of the carcass layer over the entire tread portion, and intersect with each other at the same angle as the carcass layer. .

In the present invention, the tread pattern of a tire having such a configuration is achieved by arranging a plurality of pairs of lugs, each consisting of lugs 11 and 12, arranged in left and right pairs on the tread surface 10, at equal intervals in the circumferential direction. Configure. Each lug 11.12 is formed into a surface shape in which long sides 13.14 and short sides 15°16, which are inclined in opposite directions with respect to the circumferential direction, are connected to form a substantially slanted shape, and these long sides The angles that 13.14 and short sides 15.16 make with respect to the circumferential direction are both 45 degrees. Since the long sides 13.14 and the short sides 15.16 are inclined in opposite directions relative to the circumferential direction, the angles that these two sides make with respect to each other at their junctions are right angles. Long sides 13, . The end portions 17,18 of 14 are bent in such a way that they extend in the transverse direction of the tire, ie at right angles to the circumferential direction. Paired left and right lugs 11.
12 is located at the center in the circumferential direction so that the short sides 15 and 16 are spaced parallel to each other in the central region of the tread portion, and further, both short sides partially overlap each other when viewed in the circumferential and transverse directions. Arrange point-symmetrically with respect to the point of symmetry on the line.

The specific dimensions of the tread portion 10 according to the above-described configuration and arrangement are as follows. The ground contact width W of the tread portion 10 is 210 mm, the width W of the short side 15.16 of the lug 11.12, and the width W2 of the long sides 13 and 14 excluding the terminal portion 17.18 are 20 n, respectively. The width W3 of .18 is 25 cranes.

In addition, the length of the short side 15.16 of the lug 11.12 and the length L2 of the long side 13.14 excluding the terminal portion 17.18 are each 70 mm, and the terminal portion 17.18 (7) Length L
3C: J: 20+n T: 7°. Furthermore, rug 11.
The long side 13.14 of 12 is connected to a position retracted inward in the axial direction from the end of the short side 15.16 located on the ground contact end side of the tread portion 1o, and the retraction amount e is equal to the short side 15. .16
It is within the range of about 5 to 15% of the length Ll, and in this example, 7
It's a crane. The distance D between the short sides 15.16 of the lugs 11.12 in the central area of the tread is 28 mm.
16 circumferential overlap measurements.

tam, the transverse overlap measure, is 28 mm.

In the illustrated example, the mutual spacing 12 between each pair of lugs in the circumferential direction is such that the end portion of one of the left and right lugs in a certain lug pair overlaps the end portion of one of the left and right lugs in an adjacent lug pair in the circumferential direction. These settings aim to improve riding comfort, reduce vibration, and improve straight-line performance.

(Effects of the Invention) In order to confirm the effects of the present invention, the tire of the present invention shown in FIG. 1 and the comparative tires (A) and CB) shown in FIGS. 2 and 3 were used. A comparative test was conducted. Second
The comparative tire (A) shown in the figure has a configuration in which the left and right lugs forming a pair are arranged inclined in the same direction, and the comparative tire (B) shown in FIG. The lugs are arranged so as to be inclined in opposite directions. In contrast to the tire shown in FIG. 1, both comparative tires have the same tread pattern only, and the construction and materials are completely the same.

The test items and test methods in this comparative test are as follows.

(1) Longitudinal traction performance: Traction during forward and backward driving was measured using a load cell.

(2) Lateral traction performance: Evaluation was performed based on the amount of tire side slip with respect to the steering wheel turning angle during steady turning.

(3) Deflection: The steering wheel was fixed and the evaluation was made based on the amount of deflection after the vehicle traveled straight a certain distance.

(4) Mud-clogging property - The amount of mud clogging between the lugs after driving for a certain distance was evaluated.

The test results are as shown in the following table using an index with the value obtained for the comparative tire (^) as a reference value of 100, and the larger each index is, the better the performance is.

As is clear from the above test results, according to the present invention, it has sufficient traction performance in the front, rear, left and right directions, can prevent mud from getting stuck between the lugs, has excellent straight-line performance, and can freely exchange positions. This makes it possible to realize a lug tire that is optimal for driving on rough terrain.

[Brief explanation of drawings]

FIG. 1 is a developed view of essential parts showing a tread pattern of a tire according to an embodiment of the present invention, and FIGS. 2 and 3 are developed views of essential parts showing tread patterns of tires not according to the present invention that were subjected to comparative tests. The park is now open. 1O-)-Red tread 11, 12- Lug 13.
14--Long side 15.16--Short side 1'7
．． 18-m-Long side terminal part Fig. 1 Fig. 2

Claims (1)

[Scope of Claims] 1. A tread comprising a tread surface portion and a pair of sidewall portions, wherein the tread surface portion includes pairs of lugs each having a left and right pair of approximately the same shape arranged at approximately equal intervals in the circumferential direction. In a pneumatic tire for running on rough terrain having a lug pattern, each of the lugs has a surface shape in which long sides and short sides that are inclined in opposite directions with respect to the circumferential direction are connected to form a substantially inclined L-shape. The left and right lugs of the pair of lugs are such that the short sides thereof are parallel to each other and spaced apart from each other in the central region of the tread portion, and at least partially overlap each other in the circumferential and transverse directions; A lug tire characterized in that the tread portion is arranged so as to extend in opposite directions from the central region to both side regions at a substantially constant inclination angle with respect to the circumferential direction. 2. In the lug tire according to claim 1,
A lug tire, wherein the left and right lugs of the pair of lugs are arranged symmetrically with respect to a symmetrical point on the circumferential center line of the tread portion. 3. In the lug tire according to claim 1,
A lug tire characterized in that the long sides of each lug extend in a substantially transverse direction with at least a portion of end portions disposed on both sides of the tread portion. 4. In the lug tire according to claim 3,
A lug tire characterized in that the length of the end portion of the long side of each lug is set within a range of approximately 15 to 30% of the ground contact width of the tread portion. 5. In the lug tire according to claim 3,
The lug tire is characterized in that each of the lugs has a long side length and a short side length that are approximately equal to each other, excluding the terminal portion. 6. In the lug tire according to claim 1,
A lug tire characterized in that the interval between the short sides of the left and right lugs spaced apart from each other in the central region of the tread portion is set within a range of about 1.0 to 2.0 times the width of the short sides.