JPH032681B2 - - Google Patents

Description

[Detailed description of the invention]

The present invention is directed to a vehicle suitable for driving on any terrain such as sand, rough roads strewn with rocks, etc., that is, an all-terrain vehicle, and in particular, a vehicle equipped with cross-ply tires on the front wheels and radial tires with a specific configuration on the rear wheels. This product relates to an all-terrain vehicle that improves durability, running stability, handling stability, vibration, and riding comfort by installing this product. All-terrain vehicles usually have one front wheel and two rear wheels, and are expected to satisfy performance requirements such as driving stability, handling stability, durability, and ride comfort even when driving on rough roads. It will be done. It is believed that these performances are largely due to the structure of the tire, and therefore improvements and research have been made from the viewpoint of the structural design of each tire itself. However, as a result of research into the specific uses and structural aspects of all-terrain tires, the inventor found that the functions required of tires, especially the front and rear wheels, are different from those of ordinary four-wheeled vehicles or two-wheeled vehicles. It has been found that the various functions mentioned above vary greatly depending on the combination of the structure of the tires installed on the front wheels and the rear wheels. For example, among the above characteristics, regarding steering stability, it is effective to increase the cornering power and lateral rigidity of the front tires compared to the rear tires.
It is preferable to use cross-ply tires for the front tires and radial tires for the rear tires. However, all-terrain vehicles drive on rough roads at relatively low speeds and with a low load, and the driving conditions are completely different from those of regular four-wheeled vehicles and two-wheeled vehicles, so they simply use regular cross-ply tires or radial tires. However, satisfactory performance cannot be obtained. Therefore, the inventor of the present invention has conducted various studies on front and rear tire structures and combinations that satisfy the above-mentioned required characteristics under the driving conditions of an all-terrain vehicle, that is, when driving on rough roads at relatively low speeds and with low loads. By combining cross-ply tires with a specific structure on the front wheels and radial tires with a specific structure on the rear wheels, durability, ride comfort,
The present invention was completed after discovering that characteristics such as running stability and steering stability can be satisfied. An embodiment of the present invention will be described below with reference to the drawings. FIG. 1 shows a cross-sectional view of a radial tire 2 used for the rear wheel of an all-terrain vehicle according to the present invention, mounted on a rim 3. In the figure, the radial tire 2 includes a pair of left and right bead wires 4, a toroidal carcass 5 having both ends secured to the bead wires 4, a belt layer 6 disposed in the crown region outside the carcass 5, and a belt layer 6 disposed in the crown area on the outside of the carcass 5. Treaded rubber 7 placed on the outside
It consists of The carcass 5 is usually 500~
2000 denier monofilament cord (hereinafter referred to as monofilament) to the equatorial plane of the tire from 75 to
They are arranged parallel to each other at an angle of 90°, particularly preferably at an angle of approximately 90°. Since a monofilament is used here, voids are removed at the interface with the rubber, and adhesion is improved, and the entire tire 2 can be reinforced while maintaining the excellent flexibility of a cordless tire. In addition, the number of strokes for monofilament is determined by considering the balance between fatigue resistance and strength.
Selected in the range of 10 to 70 ends/5cm. In addition, in the present invention, durability and handling stability are further improved by using the belt layer 6. Here, the belt layer 6 is composed of at least one reinforcing ply in which monofilaments or cords are arranged at an angle of 75° to 90° with respect to the equatorial plane of the tire. In general, the cord angle of the belt layer 6 of a vehicle tire is placed relatively shallowly with respect to the tire's equatorial plane to impart a "hoop effect" to provide rigidity to the tire lead and maintain steering stability. However, in the case of a special-purpose tire such as the radial tire 2 of the present invention, which is used for driving on rough roads strewn with rocks, etc., more important requirements are the ability to wrap around protrusions such as rocks, or the damage resistance and crack resistance of the tread portion. It is a characteristic. Therefore, in the present invention, the monofilament or cord of the belt layer 6 is set at an angle in the range of 75° to 90° with respect to the equatorial plane C of the tire as shown in FIG. This is to reinforce the part. The angle is preferably about 90 degrees as shown in FIG. It is desirable to relax the directionality. Next, the monofilament used for the belt layer 6 is usually in the range of 600 to 3000 deniers and the number of folds is
Those in the range of 10 to 70 ends/5 cm are used.
If it is less than 600 denier, the reinforcing effect of the tread portion will be reduced, and if it exceeds 3000 denier, it is not economical from the viewpoint of tire manufacturing cost. Furthermore, since the radial tire 2 according to the present invention has a lower internal pressure and has an extremely small number of reinforcing layers than general vehicle tires, it undergoes large bending deformation during running, and is therefore required to have higher bending fatigue resistance. As mentioned above, it is necessary to set the number of ends in a relatively high range, and a range of 30 to 50 ends/5 cm is particularly desirable. Further, the cord used for the belt layer 6 is constructed by twisting several monofilaments described above, and in this case, the number of twists is selected within approximately the same range as the monofilament. The monofilament used for the carcass 5 and the belt layer 6 is made of extensible organic fibers such as nylon, polyester, rayon, and aromatic polyamide. The radial tire 2 configured in this manner has a carcass 5 made of monofilament in addition to rubber.
Alternatively, since it only has the belt layer 6 and bead wire 4, it has excellent flexibility, damage resistance, and durability, and the structure is relatively simple, so the manufacturing method is also better than that of general vehicle tires. It has the advantage of being able to save a lot of steps and labor. Next, FIG. 3 shows a sectional view of a state in which a cross-ply tire 10 is mounted on the rim 9 of the front wheel of the all-terrain vehicle of the present invention. In the figure, a carcass 12 of a cross-ply tire 10 consists of at least two plies of cords made of organic fibers arranged at an angle of 45 to 60 degrees with respect to the circumferential direction of the tire. and ends near the rim flange 15. The plies are arranged so that the cords cross each other, forming a so-called cross ply.

[Table] Shows that.

[Table] A 5-level evaluation method was adopted.
The all-terrain vehicle of the present invention is characterized in that the radial tires 2 or semi-radial tires are used for the rear wheels, and the cross-ply tires 10 are used for the front wheels. The lateral rigidity is relatively higher than that of the rear radial tire 2, and the tire has excellent handling stability, ride comfort, and durability. Example Tire size 22× manufactured according to the specifications shown in Table 1
The lateral stiffness of 11.00-8 was measured and shown in the same table. In addition, actual vehicle running tests were conducted on a 125 c.c. three-wheel vehicle with Tire A installed on the front and rear wheels, Tire C installed on the front wheel, and Tire A or B installed on the rear wheel, and the results are shown in Table 2. show. It can be seen that all the embodiments of the present invention have improved steering stability and excellent ride comfort.

[Brief explanation of the drawing]

FIG. 1 is a sectional view of a radial tire used as a rear tire, FIG. 2 is a partially enlarged view of a breaker thereof, and FIG. 3 is a sectional view of a cross-ply tire used as a front tire. 2...Radial tire, 3...Rim, 4...Bead wire, 5...Carcass, 10...Cross ply tire, 12...Carcass, 14...Bead wire.

Claims (1)

[Claims] 1 The organic fiber cord is aligned in the circumferential direction of the tire.
A cross-ply tire consisting of at least two layers of plies arranged at an angle of 45 to 60 degrees and having a carcass in which the plies alternately intersect and both ends are folded back with a pair of left and right bead wires is attached to the front wheel, while the carcass is extended. A monofilament cord made of organic fiber with a property of 10 to 70 ends/5 cm is attached to the tire's equatorial plane.
A toroidal carcass consisting of at least one ply arranged at ~90° and anchored to bead wire at both ends, and a monofilament cord arranged radially outward of this carcass at an angle of 75 to 90° with respect to the tire equator. An all-terrain vehicle characterized in that a radial tire is mounted on a rear wheel, and a belt layer consisting of at least one reinforcing ply is arranged in the rear wheel.