JPH10151907A - Radial tire pair for dual-tire type truck and mounting method of the same - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a tire in which wondering performance at trail traveling, of a radial tire pair for dual-tire type truck is improved without lowering operational stability in particular. SOLUTION: In a dual tire type tire used by mounting two each outer side tire 1 and an inner side tire 2 as a pair on both sides of the same axle in a vehicle, crown radii forming a crown part outer outline is different in left and right holding a tire equator line there between and larger sides of the crown radius between the outer side tire 1 and the inner tire 2 are mounted that they are relatively adjacent to each other.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a radial tire for a two-wheeled truck, and more particularly to an improvement in wandering of a two-wheeled radial tire for a small truck.

[0002]

2. Description of the Related Art Radial tires for double-wheeled trucks are said to have problems in wandering performance and steering stability when traveling on a rut. A design technique of reducing the crown radius or arranging a large number of thin lug grooves in the tread shoulder has been adopted.

[0003]

However, when the crown radius is reduced as described above, there is a problem that early wear of the shoulder portion becomes a problem, and particularly, steering stability when the vehicle is empty is deteriorated. . Also, when a large number of thin lug grooves are arranged in the shoulder portion, the problem of early wear of the shoulder portion is also a problem.

SUMMARY OF THE INVENTION The present invention has been made as a result of studying to solve the above-mentioned problems of the prior art, and an object of the present invention is to provide a wobble for rudder running of a radial tire for a two-wheeled truck. It is an object of the present invention to provide a pair of tires having improved ring performance without deteriorating other performances, especially steering stability.

[0005]

SUMMARY OF THE INVENTION In order to achieve the above object, the radial tire of the present invention is mounted on a vehicle as a pair of outer tires and inner tires, two on each of the left and right sides of the same axle. In such a pair of two-wheeled tires, (1) the crown radius forming the outer contour of the crown portion is different on the left and right across the tire equator, and (2) the outer tire and the inner tire have larger crown radii adjacent to each other. It is configured to be attached to

Further, it is preferable that the ratio of the crown radius between the side having the smaller crown radius and the side having the larger crown radius is 0.6 to 0.9.

Further, in the method of mounting a pair of radial tires for a two-wheeled truck according to the present invention, a pair of tires having different crown radii on the right and left sides of the tire equator line forming the outer contour of the crown are separated from each other. The outer tire and the inner tire are mounted so as to be adjacent to each other.

In order to improve the wandering property, as shown in FIG. 4, it is necessary to increase the force acting on the tire from the ground to climb the slope, that is, the camber stiffness (ratio of camber thrust to camber angle). As a method for that, it is generally considered effective to reduce the crown radius of the tire. However, in this case, there is a problem in that the contact width with the road surface is reduced, and the steering stability particularly when the vehicle is empty is impaired.

In the present invention, the tires having different crown radii forming the outer contour of the crown portion on the left and right sides with respect to the tire equator line are mounted so that the outer tire and the inner tire have the larger crown radii adjacent to each other. Therefore, assuming that the outer tire and the inner tire are considered as a single tire, the central portion has a large crown radius and the both sides have a small crown radius. As a result, the crown radius of the tire is reduced, and the camber stiffness is reduced. It is possible to increase the size, that is, to improve the wandering performance. The central portion has a large crown radius, so that the steering stability, particularly when the vehicle is empty, is not significantly reduced.

Here, the ratio of the crown radius between the side having the smaller crown radius and the side having the larger crown radius is set to 0.6 to 0.9. Because it causes excessive wear and other problems such as abnormal wear.
This is because an effect of increasing the camber stiffness is not seen at 0.9 or more.

[0011]

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a perspective view of a tire pair according to an embodiment of the present invention;
A conventional tire pair will be described with reference to the drawings. Each tire size is 165R13, and the rim size is 13 × 4J. FIG. 1A shows a radial tire pair for a two-wheeled truck according to the present invention, which is mounted on a vehicle as an outer tire 1 and an inner tire 2 in pairs on each of the left and right sides of the same axle, The crown radii forming the outer contour of the crown portion are different on the left and right across the tire equator line, and the outer tire 1 and the inner tire 1 are mounted such that the sides having the larger crown radii are adjacent to each other. The ratio of the crown radii of the small and large crown radii of the tire is 0.78. FIG.
(B) shows the contact shape of the tire when the tire is empty.

FIGS. 2 and 3 are views similar to FIG. 1, but show a pair of radial tires for a two-wheeled truck according to the prior art, wherein the crown radius forming the outer contour of the crown is symmetrical with respect to the tire equator line. It has become. FIG. 2 shows a conventional example having a large crown radius, and FIG. 3 shows a conventional example having a small crown radius. When these vehicles are empty,
Corresponding to the difference in crown radius, the shape is close to a rectangle and an ellipse, respectively.

Next, in order to confirm the effects of the present invention, three types of tires were prototyped based on the specifications according to Table 1. These tires have exactly the same structure and material except for the crown radius shown in the table. For the evaluation of these tire pairs, a feeling evaluation of wandering performance in a real vehicle, a feeling evaluation of steering stability, and a measurement of camber stiffness in a room were performed. Feeling evaluation of wandering performance and steering stability in an actual vehicle
The internal pressure of 205R15 is applied to the front wheels of a 2-ton Isuzu elf car.
5kgf / cm ² , 165R13 on rear wheel with 4.5k internal pressure
gf / cm ² , and under empty conditions (front axle weight about 1400
kgf and a rear axle weight of about 700 kgf) were evaluated by traveling on a rutted road and a comprehensive test road. The evaluation is indicated by an index, with the evaluation when the conventional two-wheeled tire of tire 1 is mounted as 100. In the evaluation, a difference of 10 points clearly indicates a difference.

The indoor camber stiffness was measured by assembling a 165R13 tire into a 13 × 4J rim with a 4.5 kgf / cm ² internal pressure and a load of 670.
The average value per 1 degree camber angle when the camber angle is sequentially set to 10 degrees with kgf is the value of the conventional tire 1 as 1
It is evaluated as 00. The results of these evaluations are shown in Table 1.

[0015]

[Table 1]

From Table 1, it can be clearly seen that the radial tire pair for a two-wheeled truck of the present invention has improved wandering performance without sacrificing steering stability.

[0017]

As described above, according to the present invention, there is provided a tire pair in which wandering performance of a pair of radial tires for a two-wheeled truck during rutted traveling is improved without deteriorating other performances, particularly, steering stability. It became possible.

[Brief description of the drawings]

FIG. 1 is a view showing an embodiment of a radial tire pair for a two-wheeled truck according to the present invention.

FIG. 2 is a view showing a pair of conventional radial tires for a double-wheeled truck.

FIG. 3 is a diagram showing another conventional pair of radial tires for a double-wheeled truck.

FIG. 4 is a diagram in which a radial tire for a two-wheeled truck generates camber thrust on a slope and tries to get out of the slope.

[Explanation of symbols]

 D Differential gear 1 1 'Outer tire 2 2' Inner tire 3 Ground contact shape

Claims (3)

[Claims] 1. A double-wheeled tire that is mounted on a vehicle and used as a pair as an outer tire and an inner tire, two on each of the left and right sides of the same axle.
(2) A double-wheel type in which a crown radius forming an outer contour of a crown portion is different between right and left sides of the tire equator line, and (2) the outer tire and the inner tire are mounted so that sides having a larger crown radius are adjacent to each other. A pair of radial tires for trucks. 2. The radial tire for a two-wheeled truck according to claim 1, wherein a ratio of a crown radius between a side having a small crown radius and a side having a large crown radius is 0.6 to 0.9. versus. 3. A pair of tires having different crown radii forming a crown outer contour on the left and right sides of the tire equator line, such that the sides having the larger crown radii are adjacent to each other.
A method of mounting a radial tire for a two-wheeled truck, wherein the radial tire is mounted as an outer tire and an inner tire.