JPS60244604A - Pneumatic radial tire - Google Patents

Abstract

PURPOSE:To impart sufficiently balanced driving performance to a vehicle at a small steering angle of a steering wheel, by inclining cords of an outermost belt layer of a right-band tire as viewed in an advancing direction downwardly to the left in plan, while inclining cords of the outermost belt layer of a left-hand tire downwardly to the right in plan. CONSTITUTION:Cords 8 of an outermost belt layer 3u of a right-hand tire as viewed in an advancing direction E are inclined downwardly to the left. On the contrary, cords 8 of the outermost belt layer 3u of a left-hand tire as viewed in the advancing direction E are inclined downwardly to the right. A suitable layer formed of materials having low-rigid characteristics may be attached on the belt layer 3u as required. With this arrangement, sufficiently balanced driving performance may be imparted to a vehicle at a small steering angle of a steering wheel.

Description

DETAILED DESCRIPTION OF THE INVENTION [Technical Field of the Invention] The present invention relates to a pneumatic radial tire with improved maneuverability at small steering angles.

[Prior art]

Generally, when tires with the same belt structure are mounted on a vehicle as left and right tires on the same axis, these tires do not wear evenly. Therefore, some manufacturers have traditionally replaced the left and right tires when the tires have worn out to a certain extent in order to equalize the tire wear. However, even if this is done, the wear will not be uniform. For this reason, consideration has been given to changing the belt structure for the coaxial left and right tires attached to the vehicle (Special Publications Publication No. 45
-28203). However, even in this case, it is a circular to improve the performance at small steering angles, which is the basis of the vehicle's dynamic characteristics, unless it is installed in the vehicle with a certain concept.

Normally, when a vehicle tries to turn a corner, the load is transferred to the tires located on the outside of the vehicle on the same axis when viewed from the center of the vehicle's turning radius, and the load on the tires located on the outside is lower than when driving straight. On the other hand, the load on the inner tire becomes lighter. Therefore, for tires whose cornering force does not increase even when the load is shifted, the total cornering force on the same axis of the vehicle decreases. Therefore, unless the steering angle is increased, the lip angle is increased, and the cornering force is increased, the vehicle cannot be moved to the desired course. In particular, in high-speed vehicles, it is necessary to improve the danger avoidance performance during high-speed travel, and therefore it is important to improve the dynamic performance at small steering angles.

[Purpose of the invention]

The present invention has been made in view of the above circumstances, and an object of the present invention is to provide a pneumatic radial tire that improves the dynamic performance of a vehicle at a small steering angle in a well-balanced manner when turning right and turning left. do.

[Structure of the invention]

Therefore, in the coaxial left and right pneumatic radial tires mounted on a vehicle, the tire on the right side in the traveling direction has the outermost heald layer called 15 (the LQ diagonal direction is set as the downward left in the traveling direction in plan view). The tire on the left side in the traveling direction is a pneumatic radial tire characterized by the cord of the outermost heald layer (the diagonal direction is downward to the right in the traveling direction in plan view).

Embodiments of the present invention will be described in detail below with reference to the drawings.

A pneumatic radial tire is generally constructed as shown in FIG. FIG. 1 is a half-calf cross-sectional explanatory diagram of an example of a pneumatic radial tire. In Figure 1, 1
2 is a tread, and 2 is a carcass layer mounted between a pair of left and right bead portions 4.4. In the tread 1, an upper belt layer 3u and a lower heel 1-Jif3d surround the outer periphery of this carcass layer 2. It is located.

5.5 is a pair of left and right sidewall portions connected to a pair of left and right bead portions 4.4, and 6 is a crown portion made of I-Red 1.

In the radial tire configured as described above, the present invention particularly provides a tire trend radius different from left to right with respect to the tire equatorial plane, as described in Japanese Patent Application Laid-Open No. 57-147901. Or preferable. This-
An example is shown in FIG.

In Figure 2, the trend radius (1'R) of the tire's contact area with a large contact area is set larger than the trail/nod radius (TR) of the contact area with a small contact area, and (TR)
It is installed with the side facing the outside of the vehicle. In addition, the second
In the figure, number 7 represents the rim.

In the present invention, in the above-mentioned pneumatic radial tire, the cord inclination direction of the outermost heald layer is determined as shown in FIGS. 3 and 4. It was defined as shown in the figure.

FIG. 3 is an explanatory plan view of the right tire in the traveling direction in coaxial left and right pneumatic radial tires mounted on a vehicle. FIG. 4G is an explanatory plan view of the tie 4 on the left side in the traveling direction in the coaxial left and right pneumatic radial tires mounted on the vehicle. Furthermore, these third
In the figures and FIG. 4, arrow E indicates the direction of travel of the vehicle.

In the present invention, as shown in FIG. 3, in the tire on the right side in the direction of travel, the inclination direction of the coat 8 of the outermost belt layer 3U is downward to the left with respect to the direction of travel. Also,
In the present invention, as shown in FIG. 4, in the tire on the left side in the traveling direction, the inclination direction of the cord 8 of the outermost heald layer 3u is downward to the right with respect to the traveling direction E. If necessary, a layer made of a material having low G1 and 111 properties, such as a nylon reinforcing layer, may be appropriately added thereon.

〔Effect of the invention〕

As explained above, according to the present invention, in coaxial left and right pneumatic radial tires mounted on a vehicle, (1
) For tires on the right side in the direction of travel, the cord inclination direction of the outermost heald layer is downward to the left in the direction of travel in plan view (hereinafter referred to as
(2) The tire on the left side in the 1-te direction has a cord inclination direction of the outermost heald layer that is downward to the right in the traveling direction in plan view (hereinafter referred to as R-stack structure). Therefore, it is possible to provide the vehicle with sufficiently balanced driving performance at a small steering angle.

The effects of the present invention will be specifically explained below with reference to experimental examples.

Experimental example (1) In a radial tire with a symmetrical tread radius as shown in Fig. 1, the belt structure was
The slip angle was adjusted to ±2° for the tire with a pasted structure (tire A) and the tire with an R pasted structure (tire B).
The cornering force (CF) was compared when In this case, tire size 205150VR15, rim 6J x 15, air pressure '2.2kg/cn! And so.

These results are shown in FIG. In Figure 5, the vertical axis is the cornering force, the horizontal axis is the load, and the mark 8 is the tire.
The X marks indicate tire B, respectively. From FIG. 5, it can be seen that when the slip angle is positive, the cornering force on the tire B is high, and when the slip angle is negative, the cornering force on the tire B is high.

Therefore, the belt structure of the right tire is an L-pasted structure (Tire A), and the heald structure of the left tire is an R-pasted structure (tire A).
By setting tire B), the slip angle of the tire becomes negative at jM times to the left. Also, the heavier the load is the cornering force of the right tire A, the lighter the load is the cornering force of the left tire B.
Compared to the case where tires A are mounted on the left and right sides, the cornering force is slightly lower due to the lower load. By using tires with an L tire on the right side and an R tire on the left side, when the tire slip angle becomes positive when turning to the right,
Cornering force is greater with Tire B than with Tire A, significantly improving cornering performance when turning to the right, and preventing the decrease in cornering force on one side that occurs with conventional heald structures. This makes it possible to improve balanced performance.

(2) In a radial tire as shown in Figure 2, where the tread radius of the tire is asymmetrical and the large tread radius (TR) side is on the outside of the vehicle, the belt structure is closed to an L-attached structure (Tire C) The slip angle is ±2 for the tire with R-stack structure (tire D).
The cornering force (CF) was compared when the angle was set at . In this case, tire size 205150V1115
, rim 5Jx 15, air pressure 2.2kg/cd
= Closed.

These results are shown in FIG. In Figure 6, the vertical axis represents cornering force, the horizontal axis represents load, and the circle indicates tire C.
The Δ marks correspond to tire D. From FIG. 6, it can be seen that the cornering force of tire D is high when the slip angle is positive, and the cornering force of tire C is high when the slip angle is negative. Furthermore, referring to FIGS. 5 and 6, it can be seen that tires C and D have higher cornering force than tires A and B.

(3) Next, when tire B is installed on the left side and tire 8 is installed on the right side on the left and right sides of the vehicle on the same axis (Example 1
), When Tire 8 is installed on both the left and right sides (Conventional Example 1), When Tire B is installed on both the left and right sides (Conventional Example 2), When Tire 8 is installed on the left side and Tire B is installed on the right side. Tokuko Sho 45-282
Cornering force was compared between a tire based on the concept of No. 03 (comparative example) and a case where tire D was installed on the left side and tire C was installed on the right side (example 2). The results are shown in Table 1 below.

As is clear from Table 1, the case of the present invention (Example 1.2) is superior in cornering force compared to Conventional Example 1, Conventional Example 2, and Comparative Example. In particular, it can be seen that Example-2 is the most excellent.

(Margins below this page)

[Brief explanation of the drawing]

FIG. 1 is a half-calf cross-sectional view of an example of a pneumatic radial tire, and FIG. 2 is a calf cross-sectional view of the other side of the pneumatic radial tire. Fig. 3 is a plan view explanatory diagram of the right side tire in the direction of travel of coaxial left and right pneumatic radial tires mounted on a vehicle, and Fig. 4 is a plan view of the coaxial left and right pneumatic radial tires mounted on a vehicle. , is a plan view explanatory diagram of a tire on the left side in the traveling direction. 5 and 6 are relationship diagrams between load and cornering force, respectively. 1...2. Trend, 2...Carcass layer, 3U...
- Upper heald layer, 3d... Lower heald layer, 4... Bead part, 5... Zyde wall part, 6... Crown part, 7... Rim, 8... Cord. ] 3rd ln1 4th eye

Claims (1)

[Claims] Of the coaxial left and right pneumatic radial tires installed on the vehicle, the tire on the right side in the direction of travel is the outermost tire at Bell 1.
The inclination direction of one layer of cord is downward to the left in the direction of travel in plan view, and the cord of the outermost belt layer (
A pneumatic radial tire characterized in that the diagonal direction is downward to the right in the direction of travel in plan view.