JPS62155103A - Pneumatic tire - Google Patents

Abstract

PURPOSE:To improve tire quality and resistance against a partial wear by making different the rigidity of tread reinforcement layers opposite to each other about an equator, mounting right and left tires so as to give a reflected image relation in rigidity and controlling the relations of conicity and plysteer at a specific level. CONSTITUTION:Layers 6 and 7 comprising textile cords are arranged on the belt layers 4 and 5 of a tread reinforcement layer 3 additionally only at one side of a tire equator E, thereby making the rigidity of the reinforcement layer 3 asymmetric. And a tire so made is mounted so that the rigidity thereof will give a reflected image relation right and left. Also, the inclination of the tread reinforcement layer 3 in a direction of tire periphery, when viewed from tread side, is so made as to give a reflected image relation between both right and left tires and conicity C in this case is so set as to be larger than zero but two times as large as or less than a plysteer P. According to the aforesaid constitution, tire resistance against a partial wear can be improved.

Description

Detailed Description of the Invention (Industrial Field of Application) The present invention relates to left and right pneumatic tires mounted coaxially on a vehicle, and particularly relates to a reinforcing belt for improving the tire's uneven wear resistance. It concerns the structure of the layers.

(Prior art) Tire wear resistance is an important characteristic for tires that are used under particularly harsh conditions, such as the front wheels of front-wheel drive vehicles.One of the causes of worsening wear resistance is that one side of the tire There is so-called uneven wear due to the wear rate of one shoulder being greater than that of the shoulder on the other side. The cause of this uneven wear is that there is a difference in the wear input applied to both shoulders of the tire, and this asymmetry in human power is dependent on vehicle-specific characteristics such as alignment and steering characteristics, apart from road conditions etc. However, especially in the front wheels of front-wheel drive vehicles, it has been recognized that in many vehicles, there is a tendency for uneven wear on the inner side of the vehicle, and in some vehicles, there is a tendency for uneven wear on the outer side of the vehicle.

In addition to the uneven wear within a single tire as described above, due to the structure of the tire reinforcement layer, the amount of wear on the left and right wheels is affected by the force that is always generated in one direction on both the left and right wheels (plysteer). There is a problem that the distribution becomes uneven.

Conventionally, as a countermeasure against the former type of uneven wear inside the tire, as described in Japanese Patent Application Laid-Open No. 57-147901, the thickness of the trend rubber was made different on both sides of the tire's equatorial plane. It has been proposed to make the tread radius different, or to make the stiffness of the reinforcing layer uneven on both sides to prevent uneven wear on the side where the stiffness is increased, as described in Japanese Patent Publication No. 40-22521. ing. In addition, regarding the latter problem of uneven wear of the left and right wheels, Japanese Patent Publication No. 45-28203 and Japanese Patent Application Laid-open No. 60-244
As described in Japanese Patent No. 604, it has been proposed to change the structure of the reinforcing layer between left and right tires.

(Problems to be solved by the invention) Among the above-mentioned conventional techniques, the former Japanese Patent Application Laid-Open No. 57-1479
The method of asymmetrical tire disclosed in Publication No. 01 is asymmetrical within a range where the direction of the cords of the reinforcing layer is kept constant, so the direction of the plysteer described above must always be constant. Therefore, although the non-uniformity of wear within one tire can be resolved to some extent, the non-uniformity of the amount of wear between the left and right wheels cannot be sufficiently resolved. Furthermore, the trendy rubber thickness must be increased on one side only, and a new mold must be made, which increases costs considerably. On the other hand, the latter tire remains symmetrical, but the structure (cord direction) of the left and right wheel reinforcement layers was changed to
28203 and Japanese Patent Application Laid-Open No. 60-244604, the nature of the wear input applied to the tires mounted on a vehicle is not asymmetrical on both sides of the equatorial plane of a single tire. However, by making the left and right tires mirror images of each other on both sides of the left and right center plane of the vehicle, there is a tendency to eliminate the unevenness in the amount of wear between the left and right wheels, which makes it easier to select the mounting method on the vehicle. This makes it possible, to a certain extent, to compensate for uneven wear within a single tire.

That is, in the latter method, the structure of the reinforcing layer is made to have a mirror image relationship in the left and right tires in the above sense, and thereby the direction and magnitude of plysteer that occurs in the tires are made to be in a mirror image relationship with each other, thereby eliminating the vehicle-specific mirror image relationship. It attempts to compensate for the input.

However, if the structure of the reinforcing layer is simply made into a mirror image relationship, conicity, which is uncertain both in direction and magnitude due to fluctuation factors during manufacturing, will be added to the plysteer, and the resultant force of these conicities will be LFI). It is difficult to make the (lateral force when traveling straight) into a mirror image relationship. In addition, in this case, even if there is no conicity and a mirror image relationship of LFD is established, its size is determined by the size of plysteer that is specific to the structure of the reinforcing layer, so it is necessary to select an appropriate amount that matches the vehicle characteristics. There is a problem that the LFD value cannot be set.

SUMMARY OF THE INVENTION The present invention eliminates the drawbacks of the prior art described above and provides for simultaneously compensating for vehicle mirror input and asymmetric human forces on both sides of the equatorial plane within one tire. In addition, it attempts to control both plysteer and conicity accordingly. Therefore, according to the present invention, in order to compensate for the mirror image input of the vehicle, the structures of the trend reinforcing layers of the left and right tires are first made different so that they are mirror images of each other.

Next, a trend reinforcement layer is applied on both sides of the tire equatorial plane to compensate for the residual portion of the vehicle's mirror image input that cannot be compensated using conventional methods, as well as to compensate for random asymmetric inputs on both sides of the tire equatorial plane. Asymmetricalization is performed so that the stiffness is different. Various methods can be used for this, such as changing the number and material of the reinforcing layers on both sides of the equatorial plane, or molding the reinforcing layers with their center line shifted from the tire's equatorial plane. At this time, by changing the degree of asymmetry, the magnitude of conicity generated by the tire is controlled, and together with plysteer, the LFD value is made to match the vehicle characteristics. Furthermore, when installing it on a vehicle, after performing the above-mentioned asymmetrical process, it is installed so that the structure (direction of the cord) of the reinforcing layer of the left and right wheels and its entire rigidity arrangement are mirror images with respect to the left-right center plane of the vehicle. It is something.

Therefore, the pneumatic tire according to the present invention is a tire consisting of a carcass, a trend on the carcass, and a trend reinforcing layer between them, and the stiffness of the tread reinforcing layer is different on both sides of the tire equator. When installed on a car, the stiffness of the trend reinforcing layers on the left and right tires is a mirror image, which reduces the conicity of the tires.
and the inclination of the cord of the tread reinforcing layer with respect to the tire circumferential direction as viewed from the trend side is a mirror image of the left and right tire pair when the tire is installed on the car, and the plysteer of the tire at that time is is characterized in that 0<C≦2P, where P is 0<C≦2P.

(Function) According to the present invention, conicity, which is a lateral force component generated in a tire, can be easily controlled by intentionally imparting conicity by making the rigidity of the tread reinforcing layer asymmetric across the equator. I can do it.

That is, conicity is generally considered to be controlled by manufacturing factors, and in the case of a symmetrical tire in which conicity is not intentionally given, as shown in Fig. 3,
Although the variation in the lateral force distribution is large, by intentionally providing conicity as described above, the variation in the lateral force distribution is reduced as shown in FIG. 4. Furthermore, the conicity intentionally imparted by the asymmetricalization of the tread reinforcing layer can be controlled by the degree of symmetry, as shown in FIG. In addition, FIG. 5 shows the degree of asymmetry expressed by the ratio of the difference in stiffness between the left and right belts to the average stiffness of the left and right belts on the horizontal axis and the lateral force on the vertical axis.
It is shown that plystea hardly changes with changes in the degree of asymmetry.

From the above facts, we can conclude that the mirror image human power (
While driving, the left and right wheels tend to toe-in or toe-out, which is converted into lateral force and is referred to as F. ) can be achieved by changing the value of C so that F=C+P. At that time, the variable range practically required for C is 0〈C≦
It is 2P. The reason why the maximum value of conicity is set to 2P is that the maximum amount of toe-in and toe-out of the vehicle is within 10 mm, and the maximum value of conicity that can be compensated for is 2P, taking plysteer into consideration.

(Example) Fig. 1 shows a layer 6.7 made of textile cords on only one side of the equator E on the heald layers 4 and 5 of the tread reinforcing layer 3 provided between the carcass 1 and the tread 2 on this carcass. An example is shown in which the stiffness of the reinforcing layer 3 is made asymmetric in addition to the above.

Figure 2 shows the reinforcement layer 3 (bell) I'! An example is shown in which the center Vc of 4.5 is intentionally shifted from the equator E by 5 mm to one side to make the stiffness of the reinforcing layer 3 asymmetric.

When the tires with asymmetrical stiffness shown in FIGS. 1 and 2 are mounted on a vehicle, the stiffnesses of the left and right wheels are made to have a mirror image relationship.

Table 1 shows tires according to the present invention and tires according to comparative examples. The tire model is 165 SR13 and the rim is 5J.
Table 1 shows the results of a 20,000 km actual vehicle driving test with the X 13 installed on vehicles A and B.

Vehicle A is a small FF car (toe-in 2 MM), and when equipped with normal symmetrical tires (1), the front tends to wear inwardly. Vehicle B is a small FF car (toe-in 3 MM).
MM), and with normal symmetrical tires installed (6), the vehicle has a tendency for the front to wear to one side on the outside.

(Effects of the Invention) The improvement effect of the present invention on uneven wear of front tires is shown in FIGS. 6 and 7 in comparison with a comparative example.

As shown in Fig. 6, in Car A, when the tire (1) is conventionally symmetrical and has a reinforcing layer structure between the left and right wheels, the vehicle characteristics tend to cause toe-out while driving. , indicating one-sided wear on the inner side of the mounting. On the other hand,
In Comparative Example (2), only C is a mirror image, so the improvement is small. (31, +41° (5) is a mirror image relationship. Among them, (3) is a mirror image relationship in which C is nothing (, only P faces inward, but P alone is still not sufficient. Therefore, implementation of the present invention As an example, in (5), the value of inward < p + c is (
3) is smaller, so (3) is not improved, and in the end, in this case, both P and C are directed inward (
Case 4) has the most even wear. However, (5) may be the best depending on the vehicle.

In Car B, as shown in Fig. 7, the conventional symmetrical reinforcement layer structure (6) with the same left and right tires tends to have one-sided wear on the outside, but the implementation of the present invention has the same P+C relationship as described above. According to the example, case (9) is the best.

[Brief explanation of drawings]

Figures 1 and 2 are cross-sectional views of a tire in which the stiffness of the tread reinforcing layer is asymmetric according to the present invention, Figure 3 is a graph showing the distribution of lateral force when conicity is not intentionally applied, and Figure 4 is a graph showing the distribution of lateral force when conicity is not intentionally applied. A graph showing the distribution of lateral force when conicity is intentionally given. Fig. 5 is a graph showing the relationship between the degree of asymmetry and conicity and plysteer. Figs. 6 and 7 are unbalanced forces according to the present invention. It is a graph showing the improvement effect on wear. l...Carcass 2...Tre 7d 3...
・Tread reinforcement layer 4,5...belt 6.7...
Cordlayer Patent Applicant Brideston Co., Ltd. Figure 1 Figure 2 Figure 31X1 41j4 5th Fn! The talent of the unlit master U-ゞ Figure 6 Figure 7 is a waste shot! F+SAo ri:sA
of:, Outside SA.

Claims (1)

[Claims] 1. A tire consisting of a carcass, a tread on the carcass, and a tread reinforcing layer between them, in which the stiffness of the tread reinforcing layer is different on both sides of the tire equator, and the tire is mounted on a car. When the stiffness of the tread reinforcing layer of the left and right tires is a mirror image, the conicity of the tire added by this is C, and the inclination of the cord of the tread reinforcing layer with respect to the tire circumferential direction as seen from the tread side is A pneumatic tire characterized in that when the tires are mounted on a car, the left and right tires are in a mirror image relationship, and where the plysteer of the tires at that time is P, 0<C≦2P.