JPH01273705A - Pneumatic radial tire suitable for high speed running - Google Patents

Abstract

PURPOSE:To obtain sharp response, high grip ability and wear-resisting ability in good balance, by constituting one of 2 ply belt layers with non-extensile cord and the other with extensile cord. CONSTITUTION:On the outer surface of the crown portion of a toroid-shaped carcass 1, cords are placed with slight angles against circumferential direction (approx. 15 deg.-40 deg.) and cords are crossed with each other and 2 laminated ply 3A, 3B belt layer 4 is arranged. And in this belt layer 4, for instance belt 3A is made of non-extensile cord, of which elastic modulus is about 1,000kg/mm<2> or more, for instance metal cord. And the other belt 3B is made of extensile cord, of which elastic modulus is about less than 2,000kg/mm<2>, for instance nylon 6. By this constitution sharp response, high grip ability and wear resisting ability can be well balanced and high speed running characteristics suitable for motor sports can be obtained.

Description

[Detailed Description of the Invention] [Objective of the Invention] (Industrial Application Field) The present invention relates to improvement of a pneumatic radial tire, and more specifically, to improvements in sharp steering response (hereinafter referred to as response), high The present invention relates to a pneumatic radial tire that has a high balance of grip and wear resistance, and has high-speed running performance particularly suitable for motor sports.

(Prior art) -a, a pneumatic radial tire has a carcass from one bead part to the other bead part, and on the radially outer side of this carcass and in the area of the crown, in the circumferential direction of the tire. In contrast, it has a belt layer consisting of at least two plies of cords arranged in a direction that intersects with each other at a relatively small angle, and further has a tread layer on the outside of this belt layer.

(Problem B to be solved by the invention) However, since the conventional pneumatic radial tire with the above-mentioned configuration uses a material with approximately equal rigidity for its belt layer, it is necessary to Grip was sacrificed, and conversely, if high grip was emphasized, sharp response had to be sacrificed.

Therefore, in the past, belt materials were developed with a focus on sharp response, and high grip was achieved by selecting an appropriate rubber compound for the tread layer. The tread rubber has poor abrasion resistance and has difficulty in maintaining grip, so the problem remains that high grip must be sacrificed in order to achieve a certain level of abrasion resistance. Ta.

Therefore, the present invention was achieved as a result of studies aimed at solving the problems of the conventional pneumatic radial tires described above.

Therefore, an object of the present invention is to provide a pneumatic radial tire that has sharp response, high grip, and wear resistance in a well-balanced manner, and has high-speed running performance particularly suitable for motor sports.

[Structure of the Invention] (Means for Solving the Problems) That is, the present invention provides a toroidal carcass comprising at least one ply of layers in which fiber cords are arranged in the radial direction of the tire, and an outer peripheral surface of the crown portion of the toroidal carcass. In a tire comprising at least two plies of layers in which cords are arranged at a shallow angle with respect to the circumferential direction, and a belt layer that is overlapped so that the cords intersect with each other between each ply, any one of the belt layers One of the cords is made of a non-stretchable cord, and the other is made of a stretchable cord.

(Function) In the pneumatic radial tire of the present invention, one of the belt layers is made of a non-stretchable cord and the other one is made of a stretchable cord, so that the non-stretchable cord provides a sharp response. Further, the extensible cord makes it possible to ensure high grip performance, and furthermore, the effect of the extensible cord allows the use of a material with excellent abrasion resistance as the tread rubber layer.

Therefore, the pneumatic radial tire of the present invention has an excellent balance of sharp response, high grip, and wear resistance, and is particularly useful when applied to motorsports tires, such as lap time and ride comfort during circuit driving. It is possible to improve the

(Example) Examples of the pneumatic radial tire of the present invention will be described in detail below with reference to the drawings.

The drawing is an explanatory cross-sectional view showing an embodiment of the pneumatic radial tire of the present invention.

In the drawing, 1 is a toroidal carcass consisting of at least one ply of fiber cords arranged in the radial direction of the tire, 2 is a bead wire arranged at both ends of the toroidal carcass 1, and 3 is the outer periphery of the crown portion of the toroidal carcass 1. Place the cord on the surface at a shallow angle (15° to 4°) to the circumferential direction.
The belt layer is composed of at least two plies 3A and 3B arranged at an angle of 0°), and the belt layer is stacked so that the cords intersect with each other between the plies. 4 is a tread portion which is the tread surface of the tire.

Here, one of the belts 3A and 3B of the belt layer 3 (for example, 3A) has an elastic modulus of 1000.
0kr/- or more non-stretchable cord, and the other one (for example, 3B> has an elastic modulus of 2000kg/+m1
It is important that the cord be constructed of the following stretchable cords, which can improve sharp response, high grip, and abrasion resistance in a well-balanced manner.

The elastic modulus of the cord is calculated by reading the stress and elongation from the stress elongation curve when tensile strength is applied to the cord.
The stress at % elongation (S indicates the cross-sectional area of the cord) was calculated.

Non-extensible cords with an elastic modulus of 10,000 kr/- or more include metal cords such as steel cords, and extensible cords with an elastic modulus of 2,000 kr/- or less include nylon 6, nylon 66, polyester, rayon, and polyvinyl. Examples include synthetic fiber cords such as alcohol.

In addition, as shown in the drawings, the auxiliary belt layer 5 can be further arranged at an angle of 0 degrees with respect to the tire circumferential direction,
A suitable material for the auxiliary belt layer 5 is a spirally wound cord made of nylon 6 or nylon 66.

In addition, when the above-mentioned auxiliary belt layer 5 is not used, both sides of the carcass side belt layer 3B are extended, and both extension parts are
It is preferable to bend it so as to cover both sides of the tread side belt layer 3A.

By configuring the belt layer 3 as described above, this pneumatic radial tire has a balance of sharp response, high grip, and wear resistance compared to conventional pneumatic tires, and is particularly suitable for motorsports. can be obtained.

Next, the effects of the pneumatic radial tire of the present invention will be further explained using test examples.

(Test example) Tire size: front 1801550x13, rear 2
The following configuration was added to the 401570x13 radial tire.

That is, two layers of 1260 d/2 nylon 66 cord were arranged at an angle of 90 degrees with respect to the tire circumferential direction as a toroidal carcass.

In addition, as a belt layer, on the tread side, wires with a diameter of 0.23.
1×5 and elastic modulus is 1soo.

kg/rod steel cord is placed at an angle of 22 degrees to the circumferential direction of the tire, and 1 piece is placed on the carcass side.
500d/3, elastic modulus is 750kir/nj
The polyester cords were arranged so as to intersect with the staple cords at the same angle.

Furthermore, the tread layer was made of a high-oil, high-carbon general-purpose race compound, and the tread was a smooth tread (slick tread) as shown in the figure. Spiral auxiliary cords made of 1260 d/2 nylon 66 cord were placed on both sides of this tread layer at an angle of 0 degrees with respect to the circumferential direction of the tire.

Other manufacturing conditions follow the conventional radial tire manufacturing method.
A pneumatic radial tire of the present invention was obtained.

On the other hand, for comparison, a pneumatic radial tire (conventional product) was manufactured under the same conditions as above, except that steel cords similar to those described above were arranged in a manner that crossed each other on both the tread side and the carcass side as the belt layer. It was created.

Table 1 shows the results of evaluating the lap time index (the larger the index, the faster the lap time) and the actual vehicle feeling during circuit driving for these two types of radial tires.

As is clear from the above table, the pneumatic radial tire of the present invention has an excellent on-vehicle feeling compared to conventional tires, and as a result, the lap time index is also improved.

[Effects of the Invention] As explained above in detail, the pneumatic radial tire of the present invention has one of the belt layers made of a non-stretchable cord and the other one made of an extensible cord.
The non-stretchable cord ensures a sharp response, the stretchable cord ensures high grip, and the tread rubber layer has excellent abrasion resistance due to the action of the stretchable cord. becomes possible.

Therefore, the pneumatic radial tire of the present invention has an excellent balance of sharp response, high grip, and wear resistance, and is particularly useful when applied to motorsports tires, such as lap time and ride comfort during circuit driving. It is possible to improve the

[Brief explanation of the drawing]

The drawing is an explanatory cross-sectional view of the pneumatic radial tire of the present invention. 1...Troidal carcass 2...Bead wire 3...Belt layer 3A...Belt (tread fly) 3B...Belt (carcass side) 4... ...Tread section 5...Auxiliary belt layer agent Patent attorney Yasu Miyoshi Male 1...
Toroidal carcass 2... Bead wire 3... Belt layer 3A... Belt (tread [11) 3B... Belt (carcass side) 4... Tread portion 5. ...Auxiliary belt layer

Claims (1)

[Scope of Claims] A toroidal carcass consisting of at least one ply of layers in which fiber cords are arranged in the radial direction of the tire, and a layer in which the cords are arranged at a shallow angle with respect to the circumferential direction on the outer peripheral surface of the crown portion of this toroidal carcass. A tire comprising at least two plies of belt layers stacked one on top of the other with cords intersecting each other between each ply, one of the belt layers being a non-extensible cord;
This pneumatic radial tire is suitable for high-speed driving and is characterized by having the other end made up of an extensible cord.