JPS5861008A - Radial tire inflated by air for heavy vehicle - Google Patents

Abstract

PURPOSE:To improve braking force and turning performance at the wet road surface as well as to maintain resistance to wear, cruising capability at high speed, etc. in such a way that auxiliary grooves with specific width which are channeled from shoulder grooves to the tread end are arranged on shoulder ribs of the tread. CONSTITUTION:In a radial tire on which a pair of zigzag shoulder main grooves 1 whih are successively running in the peripheral directions are formed on the outer peripheral face of the tire tread, the tread surface is divided into center rib portions (A) and a pair of shoulder rib portions B, and auxiliary grooves 2 which are channeled from the shoulder main grooves 1 to the tread end TE, the width of the auxiliary grooves 2 are arranged by angles of 60-120 deg. to the tire pheripheral directions, and depth d of the grooves is formed within the range of 50-100% of the depth D of the main grooves 1. Further, the auxiliary grooves 2 are formed such that in their cross section, the width is formed so that the bottom part can be larger than the tread surface.

Description

DETAILED DESCRIPTION OF THE INVENTION This invention provides uneven wear resistance, handling stability, fuel efficiency, and
1] f/J of geological properties, etc., without harming the ability 1j lN
This invention relates to a radial tire for heavy vehicles that has improved braking force and turning performance on wet roads.

In general, the braking force and turning performance of a tire on a moist road surface can be improved by effectively removing water between the tread + ffi and the road surface during driving. To achieve this, in lip type tires, it is necessary to increase the groove width or groove depth of the zigzag main groove that runs in the circumferential direction, increase the groove volume (to efficiently remove water to the rear of the tire, or increase the width of the tire). It is possible to adopt a method that removes water in the axial direction of the tire by using a so-called rib-lug type or lug type in which horizontal grooves are arranged in the axial direction of the tire.The Al1 method reduces the rigidity of the tread surface and improves wear resistance, transfer, and low drag performance. In addition, the latter method significantly impedes the above-mentioned properties inherent to the zigzag rib.Moreover, especially in steel radial tires that use a highly rigid fiber cord such as steel for the belt reinforcing layer, the appearance of zigzag ribs So-called railway wear where corner parts are worn extremely, heel-and-tread wear where one rib end or block end wears out in some parts of the joint, and shoulder side rib ends wear more rapidly than medium-fired ribs) Phenomena such as shoulder drop wear are likely to occur.

Therefore, when changing the design of the tread pattern, these issues must be taken into consideration.From this point of view, the rib pattern is adopted as a legal system, and by incorporating fine lateral IJI, that is, ziping, the tread surface can be improved. A method has also been adopted in which water is effectively removed by increasing the wiping effect by increasing the edge.However, this method also has limitations on the depth and shape of the ziving process, and the braking force in wet roads is limited. Second, there is a limit.

The present invention has been made in view of the above circumstances, and is based on ribbed ribs and shoulder lips, and forms minor grooves of a specific shape. 1/1: This vehicle maintains high-speed cruising performance, low fuel consumption, handling stability, riding and D-position, and also achieves improvements in braking force and turning performance on wet road surfaces. Therefore, the present invention has developed a method of disposing a pair of zigzag-shaped shoulder main grooves continuous in the circumferential direction on the outer circumferential surface of the tread.
, the tread surface is separated from the central rib portion (Al) sandwiched between the shoulder grooves and the shoulder rib portions (B) located on both sides of the shoulder groove (approximately 90° with respect to the divided tread and the tire equatorial plane (from the arranged cords). a carcass, and a belt layer disposed between the carcass and the tread;
Groove width that opens from the shoulder groove to the rud end: 1. O-
This is a pneumatic radial tire for heavy vehicles, characterized by having a 4.5 mm sub-groove. Embodiments of the present invention will be described below with reference to the drawings.

FIG. 1 shows a partial plan view of the tread of the radial tire of the present invention. In the figure, a pair of zigzag-shaped shoulder main structures (1) that are continuous in the circumferential direction are arranged on the outer circumferential surface of the tread, and the trend surfaces are arranged in the shoulder main grooves (1) and the medium-heat rib part FA). The phantom shoulder rib part (divided into B+. Next, the secondary fJI? which opens from the aforementioned raceway part groove (1) to the tread end FT11). (21 is arranged.In general, the radial tie A11 for type vehicles has a lower ground pressure in a part than the center of the tread, and may be reinforced with a highly rigid son-in-law cord.
red stiffness is low because it is located at the edge of the layer). Therefore, forming a lateral groove in this area means heel-and-toe wear, LP 脣/81! It is said that this is undesirable because it further increases wear and tear. In other words, when the tire runs in the P direction in Fig. 1, shoulder drop wear occurs when the minor groove (2) (
When the ground plane transitions from the rear end fgl of some blocks (lower a) to the tip fF1 of block +lh), the rear end of block (3a) (Yfj has a minor groove (2) Therefore, slippage occurs on the grounding pin.On the other hand, the tip of the block (il)
The rear end of block (3a) is smaller than El (El), resulting in uneven slippage on its grounding right circle.
Wear occurs preferentially near the rear end (al) of the block (lower a) and the V end. Therefore, the inventors investigated the relationship between the width of the sub-groove and the abrasion, and found that the Width is 4.5
It was found that improvements in braking force and turning performance on wet road surfaces were observed. Here, the groove width of the sub-groove is the width TWb on the tread surface, as is clear from FIG. 3 showing the cross section of the sub-groove, and also means the dimension when filled with standard air pressure.

Furthermore, the cross-sectional shape of the sub-groove is such that the groove width is larger inside the groove than on the tread surface, as shown in FIG.
Alternatively, as shown in Fig. 4, the groove width gradually increases from the tread surface to the groove bottom t.
As shown in the figure, grooves are formed so that they gradually decrease toward the bottom.

Various shapes can be adopted, but especially when the shape shown in Fig. 3 or 4 is adopted, when the tire makes contact with the road surface, the spines (E, F) of the minor grooves connect with each other. In order to
The surface of the shoulder rib has excellent performance with almost the same gap as that of a continuous rib, and the prevention of IM drop wear is even more effective, and the water in the shoulder main groove flows into the minor groove that opens to this. Inside! Since the damping is removed toward the tread end, deterioration of braking performance on wet road surfaces can also be prevented. Furthermore, the angle (,
2) is in the range of 60° - 120°, and is preferably located at the shoulder rib part (inner corner (4) of Bl). The corners of (3a, 5b, 3c) are formed into obtuse angles to effectively prevent uneven wear at the corners P +1.L
sell. Next, in Figure 2E, the depth of the minor groove (2) is d.
j is the depth of the shoulder main groove (1) D) 50-1[]
It is preferable to select the area around D to improve drainage.
In this case, the depth of the minor groove (2) is approximately constant from the main groove (1) toward the tread edge, and the depth is gradually increased or decreased above the tread edge, or the depth is Hang it in multiple tiers inside.

In addition, in the present invention, the medium heat rib portion of the tread surface (11 for Al)
By arranging one or two medium-heat main grooves in the circumferential direction having approximately the same groove width as the Njorder main groove described above, it is possible to further enhance the drainage effect on the tread surface. Here, the circumferential zigzag angle (β
) is the second place.

Rolling resistance: 10-30 in the circumferential direction due to extreme wear at the protruding corners of the 9 lip, so-called railway wear.
Set to a range of °. In addition, the groove width (Wl) of the main groove (1) is preferably set within the range of 1045% - ZO, taking into account the wear resistance of the tread surface and the balance of drainage performance. Trend In order to uniformly deepen the ground contact force distribution of the tread surface and to equalize the wear caused by running on the tread m1, it is necessary to maintain high rigidity in this area. ”50
% range is more desirable. Please note that the central rib part (
A) Of course, the tread pattern can be changed by using various shapes of zibbing etc. as necessary.

FIG. 6 shows a partial plane N of another embodiment of the radial tire of the present invention. In the figure, the minor groove (2) extends from the corner of the dar rib (13) and the tread end, respectively, in the circumferential direction.
) and a relatively narrow diagonal groove (2b
). Here, the cross-sectional shape of the diagonal qη (2b) is such that the groove width inside the groove is enlarged as shown in Fig. 3.

However, the radial tire of the present invention is based on a rib type, and by arranging relatively wide grooves of 10-45 mm on the shoulder ribs, the radial tire of the present invention has various excellent properties inherent to the rib type. '1. Do you want to maintain your ability and do it at Danasou? It is possible to improve the control of high humidity +78rtAy, and to further improve the performance by specifying the shape and depth of the sub-groove as described above in relation to the shape of the rib.

Example 1 Using the tread pattern shown in FIG. 1 as an example of the present invention and the l/red pattern shown in FIGS. 7 to 9 as comparative examples,
14PR steel radial tires were manufactured. Tire T+, No. 11 (Old) The results are shown in Table 1 using the method described above.(1) Braking power at wet lI! ,Z
- Using a D-type truck, apply the specified internal pressure, and after running a specified distance for familiarization, determine the braking distance from a speed of 8Q kn/H, and use Comparative Example 1 as a reference and show the braking distance as a first-line value. The smaller the value, the worse the braking performance.

0 (2) Fuel efficiency The above tire was mounted on a 7.00TX20 rim e and the transfer resistance was measured on a 60 inch diameter drum under the conditions of specified air pressure and speed of 80 m/h. 17
Shown as J vs. 1゛゛゛. The smaller the value, the better the fuel efficiency.

(3) Steering Stability Dry Concrete 1 - Feeling evaluation and acceleration change measurement during slalom driving and chicane driving with a constant nuvede on the road surface, and steering wheel angle when driving on a wavy or protruding road surface of several quantities Data on the amount of change is evaluated and expressed as an index.

The larger the index, the better the overall steering stability.

(4) Uneven wear Ratio between the amount of wear on the shoulder rib and the amount of wear on the center rib of the tire while installing tires on the same shaft of the same vehicle and replacing them at regular intervals (the closer to 10, the closer to uniform wear)
A value closer to 100 indicates that the tread surface is more evenly worn.

Table 1: Implementation (Fll Comparative Example 1 Comparative Example 2' Comparative Example 3 Tread pattern Fig. 1 Fig. 7 Fig. 8 Fig. 9 Width of minor groove (in m), 311 m -1611
315m++: (index)
:(1) Benefit distance on wet road surface
' 88 100 89 96・(2-wheel fuel efficiency ' 1011100・103 104j
i (311!il + fir stability '10411
00'101 97□, (4111@IJ Pf
, l +09100 95'1071゜□ 1 ' □ -,,,,,,,,,j

[Brief explanation of drawings]

FIG. 1 is a partial plan view of the tread of the tire of the present invention, FIG. 2 is a cross-sectional view of the tire shown in FIG. Other embodiments of the tire of the invention, FIGS. 7-9 are partial plan views of the tread of a conventional tire. 2 Figure 1 Figure 2 Figure 6 Figure 4 WLI Figure 5 Figure 6 Figure 7 Figure 9 Figure 8 Figure 35

Claims (1)

[Claims] (11. A pair of zigzag-shaped shoulder side main grooves continuous in the outer circumferential surface of the tread +ff1L,) The central rib portion (Al
and a carcass consisting of cords arranged approximately (?0°f) with respect to the equatorial plane, and a carcass arranged between the carcass and the tread. Bear L/l
・The above-mentioned shoulder rib portion (Bl has a groove width 1.
A pneumatic radial tire for both heavy and heavy use, characterized by a 5ml sub-groove. (2) The radial diamond according to claim 1, wherein the minor groove is arranged at an angle i of 60° to 120° with respect to the tire circumferential direction. (3) The minor groove has a groove depth of 5o-i of the shoulder main groove. The radial tire according to claims 1 and 2, wherein the radial tire is within the range of 0%. (4) The radial tire according to claim 1, wherein the minor groove opens from the inner corner of the soyolder rib to the tread end. The f51 tgll structure has a radial tire according to claim 1, in which the groove width in the cross section is wider at the groove bottom than at the tread surface. The radial tire according to claim 1, wherein the tread width (TW+) is in the range of 15-30'Z.