JPH02307993A - Pneumatic tire - Google Patents

Abstract

PURPOSE:To obtain the subject tire having excellent durability and realizing light weight and low fuel cost by reinforcing carcass or belt with a cord comprising strands of steel material containing specific amounts of carbon, silicone and nickel and having contracted part for tensile testing. CONSTITUTION:Strands having >=46% degree of contraction for tensile testing derived from steel material containing 0.82-0.95wt.% carbon, 0.5-1.0wt.% silicone and 0.1-0.2wt.% nickel are stretched by a wet stretcher, etc., and subjected to twisting process to produce steel cord. Then, at least one of carcass and belt is reinforced with the steel cord, thus a tire is produced to afford the aimed pneumatic tire having improved durability under severe conditions and realizing light weight and low fuel cost.

Description

DETAILED DESCRIPTION OF THE INVENTION (Field of Industrial Application) This invention relates to a pneumatic tire reinforced with steel cords.

(Prior Art) A carcass and belt reinforced with steel cords are used as pneumatic tires for automobiles.

And the above steel cord has JI5 0350
Piano wire 5WR372A, 5WR57 specified in 2.
7A and SWR582A, etc., but recently, in order to improve the strength of the steel cord and reduce the weight of the tire, there has been a trend to use iron materials with a high carbon content (Japanese Patent Laid-Open No. 57-51502). (see official bulletin).

(Problem to be Solved by the Invention) However, when the carbon content exceeds 0.85%, the strength increases, but on the other hand, the steel cord has poor toughness, and when a pneumatic tire steps on a protrusion, the above-mentioned steel cord There was a problem that the cord easily broke.

By reinforcing pneumatic tires with steel cords that are both strong and tough, this invention makes tires lighter and more fuel efficient, as well as improving tire durability under harsh conditions. It is something.

(Means for Solving the Problems) In order to solve the above problems, the pneumatic tire of the present invention has a steel cord reinforcing at least either the carcass or the heald that has a carbon content of 0.82 to 0.95%.
, a wire made of iron material with a silicon content of 0.5 to 1.0% and a nickel content of 1 to 0.2%, with an aperture of 46% or more during a tensile test. Ru. That is, the conventional piano wire 5WR572A
, SWF SH577A, 5WR382A, etc., has a higher carbon content, and has a 0.5% carbon content compared to conventional piano wire.
The silicon content, which used to be 12% to 0.32%, was reduced to 0.
．． 5 to 1.0%, and 0.1 to 0.2% of nickel, which was not contained in the piano wire material No. 2, is contained.

Note that the aperture is expressed as the ratio (%) of the difference between the cross-sectional area of the narrowest part of the wire of the sample after cutting and the original cross-sectional area to the original cross-sectional area when the wire is subjected to a tensile test.

(Function) By increasing the carbon content, the strength of the steel cord is further improved, which reduces the amount of tension used in the tire, makes the tire lighter, reduces fuel consumption during driving, and improves the safety of the tire. 61 can be maintained. However, if the carbon content is less than 0.82%, no effect will be obtained;
If it exceeds this, the toughness will be insufficient. The metal structure is strengthened by increasing the silicon content, and the addition of nickel prevents a decrease in toughness, improving the durability and performance of the tire under severe conditions. However, if the silicon content is less than 0.5% or the nickel-containing type is 0.1%
If the silicon content is less than 0.2%, there is no effect; on the other hand, if the silicon content exceeds 1.0%, the toughness will decrease significantly, and if the nickel content exceeds 0.2%, the amount of nickel used will increase. The effect of preventing deterioration in toughness does not improve if only °ζ is used.Also, the strength and aperture of the strands change depending on the wire drawing conditions during cotton manufacturing, and when one reaches -F, the other tends to decrease. However, when the reduction of area is less than 46%, the toughness is insufficient and the desired effect cannot be obtained.

(Example) Wire drawing was performed using wire rods with the composition shown in Table 1 below,
This is used as plated raw cotton, and Cu/Z n − is coated on its surface.
Brass with a composition of 64/36 was plated to a coating weight of 6 g/kg, and Examples 1 to 3 and Comparative Examples 1 to 4 were plated.
A steel cord for the tire shown in was manufactured.

Table 1 Composition, Minutes Example Comparative Example CO, 85% 0.82% Si 0.8(i% 0.20%Ni 0
．． 14% 0.01%Mn Q, 50%
0.50%P 0.005% 0.005%S
O,003% 0.003%Cu O,
01% 0.01%F e Remaining amount
Remaining Amount Example 1 Multi-plated raw cotton having the composition shown in Table 1 above was drawn using a wet wire drawing machine and twisted to produce a class 311 steel cord. 24
．． Three types of pneumatic tires, Example 1, Comparative Example 1, and Comparative Example 2, were manufactured by using a 5-14PR belt and a 4-ply carcass of polyester cord 15000/2. The processing conditions and physical properties of the wire are shown in Table 2 and FIG. 1 below.

Table 2 Example 1 Comparative Example 1 Comparative Example 2 Diameter of raw wire (m ) t, 55 1.75
1.55 Diameter after drawing (■) 0.35 0.3
5 0.35 Processing degree (%) 94.9
96.0! 31.9 aperture (%)
47.6 45.6 44.2 Strength (kgf/
sgs”) 293 291 ' 29
2 The structure, strength, number of ends, and number of belts of the steel cord made of the above-mentioned cotton are shown in Table 3 below.

Table 3 Example 1 Comparative Example 1 Comparative Example 2 Steel cord 3 Xo, 20+6 Xo, 35 coat strength (kgf) 195 194
195 IF number (pieces/2.5cm+) 13
13 13 Number of belts 4 4
4 The performance of the pneumatic tire using the above steel cord is shown in Table 4 below.In the table, the plunger test shows the energy of the tsudokai through the tread with a screwdriver-shaped opening with a diameter of 16 m as an index. . In addition, high-speed durability indicates the results of the drum test specified in FMVSSI 19, and cord breakage indicates the number of belt breaks after being installed in a 101-load dump truck and driving through a quarry "C" as an index. Ta.

Table 4 Example 1 Comparative example 1 Comparative example 2 Plunger test 109
100 93 high speed durability
Pass Pass Pass code expired 30
100 165 Example 2 Plated raw cotton having the composition shown in Table 1 above was drawn using a wet wire drawing machine and twisted to produce two types of steel cords. Example 2 and Comparative Example 3 were used for the carcass of the tire, and the same steel cord as in Comparative Example 1 was used for the belt.
We prototyped different types of pneumatic tires. The processing conditions and physical properties of the wire are shown in Table 5 below.

Table 5 Example 2 Comparative Example 3 Me, f! Raw cotton diameter (am) 1.00 1.
18 Diameter after wire drawing (■) 0.22 0.2
2 Processing degree (%) 95.2 96.5
Aperture (%) 49.1 45
．． 5 Strength (kgf/■”) 310 3
08 Steel cord structure made of the above strands, strong,
The number of ends and number of carcass are shown in Table 6 below (blank below) Table 6 Example 2 Comparative Example 3 Steel cord 3 +8 Xo, 22 cord strength (kgD 128 127 number of ends (pieces/2.5cm) 13
13 Force - Number of scraps 11 The results of the rotating bending fatigue test of the above steel cord were
The performance of pneumatic tires using the above steel cord is shown in Table 7 below.In Table 0, cord breakage was determined by a low-pressure running drum test at a load of JI 3100% and an internal pressure of 1.
．． Conducted under conditions of 8kg/cj and speed of 20k11/hour,
Mileage: 2000h, 4000am and 6000k
Showing the results of inspecting cord breakage with X-ray every m, (
Blank below) Table 7 Example 2 Comparative Example 3 High-speed durability Pass Pass code Cut, break (2000 km), O0 (4000 km)
+a) From Ollt (6 (+00 h)
0 5200 km't Burst Example 3 A steel cord was manufactured using the plated raw cotton shown in Table 1 above, and this steel cord was coated in a size 185/70SR14.
Polyester cord 100 used for tire belts
Two types of pneumatic tires, Example 3 and Comparative Example 4, were prototyped using 0D/2 in a two-ply carcass. Processing conditions and physical properties of the strands are shown in Table 8 below (blank below) Table 8 Example 3 Comparative Example 4 Plating Raw cotton diameter (am) 1,24
1.35 Diameter after drawing (■), 0.
25 0.25 Processing degree (%) 95.
9 96.6 aperture (%>48
．． 3 45.2 Intensity (lu+/m ”)
:)04 302-The structure, strength, number of ends, and number of belts of the steel cord made of the above strands are shown in Table 9 below.

Table 9 Example 3 Comparative Example 4 Steel cord 1 x 4
20 Number of belts: 22 The performance of the pneumatic tire using the above steel cord is shown in Table 1O below. However, the plunger test and high-speed durability were the same as in Example 1, with 0 G and no cord breakage.
The above tire is installed on a 2000 cc passenger car, and the cord breakage is shown as an index after running for 5000 rum on a rough road course made with 3-sized quarry stones sprinkled on a test course in Tsuno Town, Miyazaki Prefecture owned by the applicant. Ta.

Table 10 Example 3 Comparative Example 4 Plunger test 113 100 High speed durability Pass Pass Code broken (5
000h) 27 100 (Effects of the Invention) The pneumatic tire of the present invention has a higher carbon content and silicone content than conventional ones, and is reinforced with a steel cord containing leek)1. The high aperture greatly reduces durability when used under harsh conditions, especially the cord breaking when stepping on a protrusion such as a stone, and the cord fatigue breaking when running at low pressure.

[Brief explanation of the drawing]

FIG. 1 is a graph showing the relationship between wire strength and aperture, and FIG. 2 is a graph showing the results of a rotating bending fatigue test of steel cord. Patent applicant Toyo Rubber Industries Co., Ltd. agent Patent attorney Yoshi 1) Ryo Tsukasa Yomi (k furnace) Fatigue live (Saia) Shiu

Claims (1)

[Scope of Claims] [1] A pneumatic tire in which at least either the carcass or the belt is reinforced with a steel cord, wherein the strands constituting the steel cord have a carbon content of 0.82.
~0.95%, a silicon content of 0.5 to 1.0%, and a nickel content of 0.1 to 0.2%, and the aperture of the wire during the tensile test is 46% or more. A pneumatic tire featuring