JPS6050003A - Pneumatic radial tire for passenger car - Google Patents

Abstract

PURPOSE:To improve the uniformity and high speed durability by interposing a carcass reinforcement ply having the cord angle of nearly zero relative to the circumferential direction of tire between the carcass ply and the innermost belt ply so that a perpendicularly intersecting net structure may be formed in cooperation with the carcass ply cords. CONSTITUTION:A carcass reinforcement ply 7 in which nylon cords etc. are so arranged that the cord angle is nearly zero relative to the circumferential direction EE' of tire is interposed between the carcass ply 4 and the innermost ply 5' of belt plies 5 so that a net structure may be formed in which cords of the carcass ply 4 and cords of the carcass reinforcement ply 7 intersect perpendicularly. In this constitution, since the primary direction of elasticity of both the plies 4, 7 corresponds respectively with the direction of the tire section and the direction of the tire circumference that intersect perpendicularly with each other, the change of the cord angle of carcass cords due to the pantograph effect of the tire can be prevented. Therefore, the tire's uniformity and high speed durability can be improved.

Description

[Detailed description of the invention] The present invention relates to tire uniformity (RFy).

[11] A pneumatic radial tire for a passenger car that improves high-speed durability while increasing LFV') and free run-out to 8.

Conventionally, in order to obtain a radial tie with excellent high-speed performance, as shown in Figures 1 and 2, the cord angle with respect to the tire circumferential direction EE' is substantially A carcass layer 4 having an angle of 90° is installed, while a plurality of belt layers 5 intersecting each other at cord angles of 10” to 30° with respect to the tire circumferential direction EE′ are mounted on the carcass layer 4 in the tresotho part B. Furthermore, a cover layer 6 is placed on the outermost layer 5u of the belt layer 5.

In addition, 6a is a cord constituting the cover layer 6, 5a is a cord constituting the belt layer 5, and 5d is a cord constituting the belt layer 5.
represents the innermost layer of

Here, in conventional tires, since the carcass layer 4 and the belt layer 5d were adhered adjacent to each other, during the tire molding and vulcanization, the carcass cord layer 4 disposed in the cross-sectional direction of the tire and the tire circumferential direction were at an angle of 15° to 30°. With the belt layer 5d disposed at the angle, a puncture graph effect (compensating for tire growth by changing the angle during tire molding and vulcanization) occurs, and in the tire after molding and vulcanization, the carcass cord layer 4 is partially It was found that the tire was molded and vulcanized at an angle of 2° to 3° from the cross-sectional direction of the tire. This uneven coat arrangement of the tire carcass cord ensures tire uniformity,
Especially LFV (Lateral Force Varia)
tio+i).

1. The cover layer 6 has the function of reinforcing the belt layer 5, preventing the belt layer 5 from rising during high-speed driving, and working together with the belt layer 5 to improve the rigidity in the tire circumferential direction. ing.

The cord 6a of this cover J''t 6 is generally made of a textile coat made of a heat-shrinkable material such as a nylon cord or a polyester cord.
is arranged at approximately 0° with respect to the tire circumferential direction EE'.

By the way, in the manufacturing process of the tire with the single cover layer 6, after the belt layer 5 is placed, the tire shown in FIG.
As shown in fbl, on the outermost layer of this belt layer 5,
A cover layer 6 is arranged around the cord 6a in a tie-\"circumferential direction 7.j and approximately Oo, and its terminal portion 62
, 63 are overlapped to form a splice portion 61.

At this time, the length of the splice part 61 of the cover layer 6 in the tire circumferential direction is 1 (see Fig. 3 (al)). After that, this 11-vulcanized tire is heated under pressure in a vulcanization mold (not shown) to be vulcanized into a product tire. It is shown in Figure 3 tb).

The outer circumference of the vulcanized tire is smaller than the inner circumference of the vulcanized mold, and the unvulcanized tire is pressurized from the inside of the tire in the vulcanized mold to grow the tire. It is brought into close contact with the inner peripheral surface of the vulcanized mold.This is generally called lifting.

When lifted in this way, the carcass layer 4 and the belt layer 5 can grow in outer circumference due to their structure, but as mentioned above, the cord of the cover layer 6 grows in the tire circumferential direction. It cannot grow because it is located at almost 0°.

Therefore, the growth of the single layer 6 of birch is as follows:
The only option is for the end portions 62 and 63 to be offset from each other at the splice portion 61.

However, since the adhesive strength of the splice portion 61 is small compared to the tensile strength of the cord 6a, most of the growth is due to the tangle of the splice portion 61. As a result, the length 12 of the splice portion becomes shorter than el before vulcanization.

As a result, most of the growth of the belt layer 5 and the trend portion 6 occurs at the portion where the IIA contacts the splice portion 61 described above.

As a result, non-uniform portions occur on the circumference of the tire, and this non-uniformity contributes to vehicle vibration when the automobile travels at high speeds, and also leads to deterioration of the tire's high-speed durability. This means that when a tire is mounted on a vehicle and a high-speed durability test is carried out, the area near the splice part wears out extremely quickly, and when an indoor high-speed 11111 durability test/inspection is carried out, the splice part is almost completely worn out. Karaq・Ji～II Lateb・
This can be seen from the fact that 1. is permanent.

The present invention has been made in consideration of the above-mentioned 4JJ shield, and provides a passenger car 111' pneumatic glide run tire that overcomes the above-mentioned drawbacks and has excellent high-speed durability. The purpose is to

That is, the purpose of this method is to eliminate the above-mentioned first drawback, the adjoining adhesion relationship between the carcass layer and the belt layer (in/tagraph effect), and to reduce the second drawback, the local deformation of the splice part of the single cover layer. As a result of various experiments, the present inventors inserted a carcass auxiliary layer in contact with the carcass layer to form orthogonal mesh grooves, a.
Part 1: I discovered that I could eliminate all the flaws in one fell swoop.

Each tool consists of a pair of left and right bead parts, a pair of left and right sidewall parts connected to the bead parts, and a tread part located between the sidewall parts. , a carcass layer having a coat angle of substantially 90' with respect to the tire circumferential direction is mounted, and a plurality of layers intersecting each other with cord angles of 10° to 30° with respect to the tire circumferential direction are mounted on the carcass layer in the tread portion. In a pneumatic tire comprising a belt layer, a carcass auxiliary layer consisting of a coat having a coating angle of approximately Oo with respect to the tire circumferential direction is interposed between the carcass layer and the innermost layer of the belt layer, and the carcass auxiliary layer The gist of the present invention is a pneumatic radial tire for a passenger car, characterized in that a layer and the carcass layer form an orthogonal mesh structure.

Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings, focusing on the orthogonal mesh Ftj) structure which is the basis of the present invention. In these figures, the same parts as in FIGS. 1 and 2 are represented by the same numbers.

Fig. 4 is an explanatory diagram of a calf half cross-section of the pneumatic radial tire for passenger cars of the present invention, and Fig. 5 is a developed plan view thereof, in which the carcass auxiliary is made up of cords having a cord angle of approximately Oo with respect to the tire circumferential direction EE'l. A layer 7 is interposed between the carcass layer 4 and the innermost layer 5 (1) of the belt layer 5.

As a carcass layer 4 coat. 1. Chemical edges such as nylon and polyester are generally used during the bending process.

As a coating for the heald layer 5, steel cord is mainly used, but 111 cord, an aromatic polyamide fiber called aramit, may also be used.

As for the coat constituting the carcass auxiliary layer 7, it is sufficient to use one normally used for tires, and nylon and polyester cords are suitable, and steel, aramit, nylon, polyester, rayon/
l, f recodes are available. These are based on factors such as the lift rate during tire molding and vulcanization and the tire circumference.
・Can be used for different purposes. For example, when vulcanizing is performed using a split moat with a large lift rate during vulcanization, it is preferable to use textile cords such as nylon, rayon, and polyester, especially nylon cords. Further, in order to increase the tire circumference in the 7-way mode, steel coat or aramid cord can be used.

One layer of cover 7 is made by using rubberized paulownia coat or A2 material (so-called single-wound cord layer) in which a single cord is wound and arranged in parallel on a tire blind coat in which such coats are arranged in parallel. molded. The width of this cover layer 7 is
It is preferable that the width of adjacent belt layers 5 is also larger.

This cover has 1 so 7, 4 layers, 4 helds, and 5 layers.
When the cord is interposed between the carcass layer 4 and the carcass layer 4, the force...
The cord angle with respect to the tire circumferential direction is 9 in terms of actual Ifr■
0', the cords 7a of the cover layer 7 and the cords 4a of the carcass layer 4 are orthogonal to each other, as shown in FIGS. A network structure is formed.

This formed orthogonal network structure (d, carcass layer 4 and carcass auxiliary layer 7 are 9Q' i1 main 11!111C
The two directions coincide with the cross-sectional direction of the tire and the circumferential direction of the tire, and are perpendicular to each other. Since the coat angle does not change, the carcass layer 1 is arranged directly in the cross-sectional direction of the tire, resulting in tie 8 and uniformity, especially LFV direction 7.

Compared to conventional radial tires, which maintain the shape of the tire through the belt nozzle 5 and carcass layer 4, the tire of the present invention has a C1 cross-sectional shape due to this orthogonal mesh structure. You will be able to hold it. Therefore, the belt layer 5 effectively functions to improve other characteristics of the tire other than maintaining the cross-sectional shape of the tire, especially cornering characteristics when traveling on a curve.

Furthermore, in conventional tires in which the single cover layer 6 is disposed on the heald layer 5, local deformation at the splice part of the single cover layer is large, but the tire-like carcass auxiliary layer of the present invention has a structure in which the belt layer 5d and the carcass layer 4 are separated from each other. Because the splice is inserted between the cover and the cover, local deformation of the splice portion, which has been a problem with conventional tires, is less likely to occur. Since the carcass auxiliary layer is sandwiched between the upper and lower cord layers, this is different from the conventional belt layer 5u.
Unlike the single layer of cover placed on top, the single layer of cover deforms during vulcanization over the entire circumference of the tire, and local deformation at the splice part of the carcass auxiliary layer becomes smaller compared to conventional tires. It is from.

Furthermore, the rigidity ratio of the splice part of the single cover layer and the other parts in the tire of the present invention is significantly closer to (equal to) II/ than the ratio of the rigidity of the splice part of the single cover layer to the other parts in the conventional tire. The present inventors have clarified this.

Hereinafter, the effects of the present invention will be specifically explained with reference to experimental examples.

Experimental Example As shown in FIGS. 1 and 2, the outermost layer 5u of the belt layer 5
A cover layer 6 is placed on top of the tire (conventional tire), as shown in Figures 4 and 5, a carcass auxiliary layer 7 is interposed between the carcass layer 4 and the innermost layer 5d of the belt layer 5. tire (tire of the present invention) and No. 8 tire for comparison.
As shown in FIG. 9 and FIG. 9, a tie--(
A comparison tire) was prepared. The dimensions of these tires are shown below. Still, the end of these tires (width 50〃+m
The number of cords per cord) and the cord angle (angle with respect to the tire circumferential direction) are shown in Table 1 below.

Tire size: 175/70 SR13 belt layer (1) Steel cord composition; lX5 (main wire diameter 025)
, 40 work/t (number of cords per 5Qmm width) (2) Coat angle, 20° to the tire circumferential direction (3)
Number of plies: 12 (cords cross each other on the lower layer) Carcass layer: 1 ply, polyester cord.

1500 d/2; 35 ends, cord angle is 90" in the circumferential direction of the tire. Cover layer nylon cord; 840 d/2
,; 58 ends, cord angle is 0° with respect to the tire circumferential direction, and wrap amount is 60 mm0. It turns out that there are few. In other words, the change in carcass angle is substantial in the tire of the present invention, whereas in the conventional tire,
For comparison tires, the amount of change was 3.2 ku\・I, respectively.
U1 is facing south.

1. Molding the splice part of the single layer of the cover f14j +i
! Wrap of splice part after J:: U) Change 1hi i
1. Looking at the results, the tire of the present invention has a lower
]・I can see that there is phlegm. The fact that this rate of change is small (1) is equivalent to little or no local deformation at the cover-adding splice.

1. The following tests were conducted on these tires.

The results are shown in Table 2.

Tire uniformity test (1) RFV (Radial l;”orcc V
ari; mountain O1]), LFV (1, cJtcral
Force Variation).

The test was conducted in accordance with JASOC607r Automobile Tire Uniformity Test Method.

(2) Free rough out.

Free run out refers to the dimensional change in the tire radial direction of the tie. The peak of this change
Let to peak be the free run value l'I)-f).

This is a measure of the dimensional non-uniformity of the tire in the circumferential direction.

The internal pressure at the time of measurement was determined according to JASOC607.

High-speed durability test: Conducted in accordance with the method specified in JIS D4230. Specifically, an indoor drum testing machine (drum diameter 1707
m), conduct a high-speed durability test for each tire.

The test conditions were: internal pressure p = 2.6 K976yd, load W-357? , use rim 5JX13 as speed 14
The speed was increased from 0 Km/l, r to 10/hr every 10 minutes, and the vehicle was driven at a point where the tires would break.

Tire circumferential bending stiffness ratio (k).

The bending stiffness in the circumferential direction of the tire per unit width at the cross section of the tire at the splice part on the tire circumference, which is lower than the stiffness of the tire, and the bending stiffness in the circumferential direction of the tire per unit width at other cross sections. The uniformity of the tire was investigated from the perspective of tire rigidity using the ratio of (tire circumference) two non-uniformities k (=D).

The specific calculation method is based on the general laminate theory ("Composite Materials Engineering" edited by Takeshi Hayashi, Nikka Gien Publishing) using the carcass layer as a reference.
Calculate the bending stiffness of the sill board using .

Table 2 From Table 2, it can be seen that the tire of the present invention has a smaller LFV than the conventional tire and the comparison tire. This is because there is no change in the cord angle of the carcass cord due to the orthogonal network structure of the present invention. In addition, the RFV and free run-out (p-p value) of the tire of the present invention are smaller than that of the conventional tire and the comparison tire.
This is due to the fact that the rate of change of the splice portion of the carcass auxiliary layer is small in the tire of the present invention.

Furthermore, it can be seen that the tire of the present invention has improved high-speed durability compared to the conventional tire and the comparative tire. In other words, when comparing the speed at the time of tire failure, it is 20 K"/hr faster than the conventional tire and 10 K"/hr faster than the comparison tire.
hI - elevated.

In Table 2, as k becomes greater than 1, the non-uniformity around the tire circumference increases. Therefore, it can be seen that the tire of the present invention has less unevenness in the stiffness of the ridges on the tire circumference than the conventional tire and the comparative tire.

As explained above, the experimental results show that the tire of the present invention can improve uniformity and improve high-speed ij durability compared to conventional tires and comparative tires.

In this way, although the present invention was able to improve uniformity, LO, and high-speed durability, it was also possible to improve uniformity, LO, and high-speed durability.・By inserting the tire at almost 0° in the circumferential direction, the carcass layer 4 and carcass layer 4 are separated. fli
f4) This is due to the formation of the mesh (11) structure in the J layer.

[Brief explanation of drawings]

Figure 1 is an explanatory diagram of a meridian half cross section of an example of a conventional pneumatic tire for passenger tables; Figure 2 is its developed plan view;
Figures (a) and (bl are explanatory diagrams showing the situation in which the tin slice part of the cover layer shifts during the manufacturing process of this type of tire,
FIG. 4 is a meridional half cross-sectional explanatory diagram of an example of a pneumatic radial tire for a passenger car according to the present invention, and FIG. 5 is a developed plan view thereof.
FIG. 6 is a developed plan view showing an orthogonal mesh structure of an example of a pneumatic radial tire for passenger cars according to the present invention, FIG. 7 is a conceptual perspective view of the same, FIG. 8 is an explanatory diagram of a calf half cross section of a comparative tire, and FIG. The figure is a developed plan view. 1... Bead part, 6... Tread part, 4... Carcass layer, 5... Belt layer, 5u... Outermost layer, 5d...
- Innermost layer, 6... Cover single layer, 7... Carcass auxiliary layer. Agent: Patent Attorney Shin Ogawa ~ Patent Attorney Ken Noguchi Patent Attorney Kazuhiko Saishita 3!1A (a) Figure 3 (1)) Figure 6 Figure 7 Figure 7

Claims (1)

[Claims] Consisting of a pair of left and right bead parts, a pair of left and right sidewall parts connected to the bead parts, and a tread part located between the sidewall parts, there is a cord angle between the pair of left and right bead parts with respect to the tire circumferential direction. A carcass layer having a cord angle of substantially 90° is mounted on the carcass layer in the tread portion, and a cord angle of 10” to
In a pneumatic tire formed by arranging a plurality of belt layers that intersect with each other at 30", a cord is formed between the carcass layer and the innermost layer of the belt layer with a cord angle of approximately 0° with respect to the tire circumferential direction. A pneumatic radial tire for a passenger car, characterized in that a carcass auxiliary layer is interposed, and the carcass auxiliary layer and the carcass layer form an orthogonal network structure.