JPH03266703A - Tier for t-type emergency - Google Patents

Abstract

PURPOSE:To suppress the reduction in durability due to high inner pressure as well as the reduction and so on of tread width, so as to achieve radial function by regulating a cord angle of a belt layer as well as belt width in a specific range, and by coating a belt end with a protective layer comprising a specific rubber material. CONSTITUTION:A carcass 6 of radial disposition whose both ends are folded around a bead core 5 at a bead part 4 from a tread part 2 via a side wall part 3, is provided on a tire 1. A belt layer 7 is arranged which is composed of multiple belt plies 7A, 7B for which a belt cord is arranged at an angle of 22 deg. through 28 deg. to the equator of the tire, in the tread part 2 and on the outside along the radius of the tire of the carcass 6. A protective layer 9 for coating these is arranged on both end parts of the belt layer 7. The width WB of the belt layer 7 is set to 0.9-0.95 times as large as the width WT of the tread part 2. The protective layer 9 is formed out of rubber material whose 100% extension modulus is 18-50kg/cm<2>.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a T-type emergency tire that is excellent in high-speed running performance and handling stability.

[Conventional technology]

For example, four-wheeled vehicles are equipped with a spare tire that is used occasionally when a bank occurs in the tires that are normally installed on the vehicle.
T-type emergency tires are often used because they have a smaller tire width than the installed tires and have less storage space.

In addition, this product has an internal pressure of 4.0 kg/cm2 or more in order to maintain a nominal load that is almost the same as other installed tires even with the small tire width, and is designed to reduce costs. A carcass with a cross-brie construction is used.

[Problem to be solved by the invention]

However, in recent years, the driving performance of installed tires has been greatly improved by adopting a radial structure and promoting flattening. There is also a strong desire for emergency tires to improve running stability and handling stability in accordance with other installed tires.

Therefore, in view of this situation, the inventors of the present invention devised a plan to adopt a radial structure instead of a cross-brie structure in a T-type emergency tire in order to improve tire performance.

However, when a radial structure is introduced into a T-type emergency tire, the tread surface is curved due to the high internal pressure used, and the ground contact becomes poor, making it difficult to obtain a satisfactory improvement in driving performance. Also, new problems that must be solved have been found, such as an increase in the acting stress at the belt end, leading to early belt end '11M'.

The present invention is based on regulating the cord angle and belt width of the belt layer, and covering the belt end with a protective layer.
The object of the present invention is to provide a T-type emergency tire that can solve the above-mentioned problems and has improved high-speed running performance and handling stability through radialization.

[Means to solve the problem]

In order to achieve the above object, the T-type emergency tire of the present invention is a T-type emergency tire that is temporarily used in place of a tire installed on an automobile, and is a T-type emergency tire that is temporarily used in place of an installed tire on a car. A radially arranged carcass that is folded back around the bead core of the bead portion, and the carcass is arranged on the outside in the tire radial direction and inside the tread portion, and the belt cord is arranged at an angle of 22 degrees or more and 2 degrees with respect to the tire equator.
a belt layer consisting of at least two or more belt plies arranged at an angle of 8 degrees or less; and a protective layer disposed at both end portions of the belt layer and covering the both end portions, while the belt layer is arranged in the tire axial direction. The belt width, which is the width of
It is made of a rubber material with a 0% elongation modulus of 18 or more and 50 kg/cm2 or less.

[Effect]

The belt layer is formed of two or more belt plies, and each belt cord is arranged at an angle of 22° or more and 28° or less, which is larger than the normal cord angle.

Therefore, by crossing each belt cord between the braais, a strong truss structure can be formed, which greatly increases the in-plane rigidity of the belt, suppresses deformation of the tread surface caused by high internal pressure, and enables high speed Driving performance and steering stability performance can be improved.

Furthermore, since both ends of the belt layer are covered with a protective layer made of a soft rubber material, the stress acting on the belt ends, which increases due to the high internal pressure, can be alleviated and durability can be improved.

Note that if the belt width exceeds 0.95 times the tread width, the rubber thickness between the belt end and the outer surface of the tire will be insufficient, making it difficult to maintain the above-mentioned improvement in durability.
If it is less than 9 times, the carcass restraining force at the shield portion will be insufficient, resulting in uneven ground pressure and tread rigidity, and a decrease in running performance.

〔Example〕

An embodiment of the present invention will be described below based on the drawings.

In the figure, a tire 1 includes a tread portion 2, a pair of sidewall portions 3 extending inward in the tire radial direction from both ends of the tread portion 2, and a bead portion 4 located at the inner end in the tire radial direction of each sidewall portion 3. A T-type emergency tire that has a working internal pressure of 4.0 kg/3" or higher, so that it can be used as a normal tire with the same nominal load, for example, with an internal working pressure of about 2.0 kIr/cm". The tire width can be reduced to about 0.77 times or less.

Further, between the bead cores 5 and 5 provided in the bead portion 4, a carcass is provided with folded portions that are folded back from the inside to the outside around the bead cores 5 at both ends of the main body extending from the tread portion 2 to the sidewall portion 3. A strong belt layer 7 is wrapped around the carcass 6 on the outside in the tire radial direction and on the inside of the tread portion 2 in the tire circumferential direction.

The carcass 6 is formed from a single radially arranged carcass bridle in this example in which the carcass cord is inclined at an angle of 70° or more and 90' or less with respect to the tire equator,
The folded portion terminates at the bead portion 2 or sidewall portion 3.

As the carcass cord, an organic fiber cord made of nylon, rayon, polyester, aromatic polyamide fiber, etc. is used, preferably a polyester or aromatic polyamide fiber cord having a high elastic modulus so as to withstand high internal pressure.

Also, a bead apex 8 made of hard rubber is interposed between the main body part and the folded part of the carcass 6 and extends from the bead core 5 in a tapered manner to strengthen the tire from the bead part 2 to the sidewall part 3. Increases lateral rigidity.

Further, the belt layer 7 is formed from two inner and outer perdobribes A and 7B arranged outside the crown portion of the carcass 6.

The belt plies 7A and 7B are cord array bodies in which belt cords made of, for example, steel and each having a high elastic modulus are arranged at an angle of 22° or more and 28° or less with respect to the tire equator, and each belt cord is a ply belt cord. They are arranged in different directions so that they intersect with each other.

The belt layer 7 is formed to have a belt width WB of 0.9 times or more and 0.95 times or less of the tread width WT on the tread surface in a straight line in the tire axial direction, and
The carcass 6 is restrained with a hoop effect over almost the entire length of the carcass 6.

Therefore, in the belt layer 7, the belt cords and carcass cords between each braai intersect with each other to form a strong truss structure, which greatly improves the in-plane rigidity of the belt. While suppressing the deterioration of the tire, it is possible to exhibit the excellent steering stability and high-speed running performance characteristic of radial tires.

In addition, in order to relieve the stress acting on the belt end which increases due to the high pressure and to suppress the severance at the belt end, the ply width WB2 of the outer belt ply 7B is adjusted.
is made smaller than the ply width WBI of the inner belt ply 7A, and each ply end of the belt plies 7A and 7B is covered with a protective layer 9.

Note that the belt width WB is the maximum of the belt layer 7 in the tire axial direction, and therefore, in this example, the bridle width WBI is set to 0.9 times or more and 0.95 times or less of the tire width WT.

If the brie width WBI, that is, the belt width WB, is less than 0.9 times, the restraining force on the carcass at the shoulder portion will be insufficient and it will be difficult to improve running performance, and if it exceeds 0.95 times, the belt edge and The rubber thickness between the outer surface of the tire and the outer surface of the tire is insufficient, which impairs tire strength and reduces durability. In addition, in order to maintain the durability and the binding force to the carcass, the briar width WB2 should be at least 0.80 times the tread width WT and 0.9
It is preferable that it is 0 times or less.

As shown in an enlarged view in FIG. 2, the protective layer 9 includes, in this example, a braai piece 9A that covers the ply end of the inner belt ply 7A, and a ply piece 9 that covers the outer belt ply 7B.
B, and the ply pieces 9A and 9B are each 100%
It is made of a soft rubber material with a tensile modulus of 18 or more and 50 kIr/cm2, and the coating thickness t is 0.3.
It is set to not less than ■ and not more than 0.6■.

When the 100% elongation modulus exceeds 50 kg/em'' and the coating thickness t is less than 0.3 tm, the effect of alleviating the applied stress is poor, and the sevareshine permeates through the ply ends, reducing durability. Further, when the 100% elongation modulus is less than 181x/cm2 and the coating thickness t is 0.
If the length exceeds 6 m, the movement of the ply ends becomes excessive, impairing steering stability, while increasing the internal temperature and conversely decreasing durability.

In the present invention, a band layer may be formed on the outside of the belt layer 7 depending on the tire performance of other installed tires to suppress rich ink etc. on the belt layer 7 due to high speed rotation. The seat cane has band cords made of organic fiber cords arranged at a shallow angle to the tire equator.
Alternatively, a band braid made by continuously winding a band cord in a spiral manner can be used, and a heat-shrinkable nylon fiber cord can be suitably used as the band cord.

〔Concrete example〕

It has the tire structure shown in Figure 1 and the tire size is T1.
A 35/70RI6 tire was prototyped based on the specifications in Table 1, and the handling stability and durability of the tire were measured based on the test conditions below, and the measurement results were compared with conventional tires and shown in Table 1. Describe it. Additionally, tire strength and rim detachability are added to the same table.

1) Steering stability: The vehicle was driven under the following conditions and the feeling was evaluated using a 5-point method.

2-1) General durability: Using a drum tester, the drum was run under the following conditions and the running time until breakage occurred was evaluated.

2-2) High-speed durability: Using a drum tester, the tires were run under the following conditions and evaluated based on the step speed and running time at which tire failure occurred.

3) Tire strength: A plunger with a diameter of 19 m is pressed against a tire with an internal pressure of 3.7 + r/m at a speed of 50.0 ± 2.5 ta per minute, and the plunger pushing force (F: kgf) when the tire breaks
) and plunger travel amount (P: C1m), the following formula W-
Destroyed energy from FXP/2.

4) Rim detachability: Based on JATMA tire safety standard 1984-4.2,
Evaluation was made based on rim detachment drag.

〔Effect of the invention〕

As with the ridges, the tire of the present invention regulates the cord angle and belt width of the belt layer, and at the same time covers the belt end with a protective layer, which prevents a decrease in durability and a reduction in tread width due to high internal pressure. It can be suppressed, it can be made radial, and high-speed running performance and steering stability performance can be greatly improved.

[Brief explanation of drawings]

FIG. 1 is a sectional view showing one embodiment of the present invention, and FIG. 2 is a sectional view showing an enlarged end of the belt. 2-Tread part, 3-Sidewall part, 4-Bead part, 5-Bead core, 6-Carcass, 7-Belt layer, 7A, 7B-Belt ply, 9-Protective layer, WB--
-Belt width, W T-) Red belt width.

Claims (1)

[Claims] 1 T used temporarily in place of tires installed on automobiles
This type of emergency tire includes a radially arranged carcass in which both ends of the carcass are folded back around the bead core of the bead part from the tread part to the sidewall part, and the carcass is arranged on the outside of the carcass in the tire radial direction and inside the tread part. At the same time, the belt cord should be at least 22 degrees and 28 degrees from the tire equator.
a belt layer consisting of at least two or more belt plies arranged at an angle of less than The belt width, which is the width, is 0.9 times or more and 0.95 times or less than the tread width, which is the width of the tread surface in the tire axial direction, and the protective layer is 100%
A T-type emergency tire made of a rubber material with a % elongation modulus of 18 or more and 50 kg/cm^2 or less.