JPS5911443B2 - high speed pneumatic tires - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION This invention relates to a high-speed pneumatic tire.

This invention relates to the structure of an ultra-flat racing tire in which the outer surface of the tread portion has a substantially cylindrical shape with an aspect ratio, that is, a ratio between the cross-sectional height of the tire and the maximum width of the tire, in the range of 0.25 to 0.75. This is a suggestion for improvement.

The performances required of this type of tire include higher handling stability, acceleration, braking characteristics, and high-speed durability.

This type of tire is not used for long periods of time under mild conditions like general passenger car or truck tires, but is used for relatively short periods of time under extremely harsh conditions. Therefore, if the above-mentioned characteristics of the tire reach a certain level, not only will the tire not be able to run satisfactorily, but if there is a defect in the structure or materials, severe mechanical and thermal stimulation will be added, resulting in extremely high tire performance. Destruction is reached within a short time.

On the other hand, the remarkable improvement in high-speed performance accompanying recent advances in automobile-related technology has led to an ever-increasing demand for raising the above-mentioned characteristics to even higher levels.

Various proposals have been made in the past to improve the running performance of this type of tire.

Generally speaking, an important consideration is how to increase the contact area with the road surface during load transfer, that is, how to increase the contact area, and one way to achieve this is to increase the width of the tire and reduce the cross section of the tire. The idea is to secure ample ground contact area by using a flattened tire shape, but this type of thinking naturally has its limits due to its relationship with the vehicle body.

The second method is to increase the outer diameter of the tire to an extremely large extent in order to secure the ground contact area in the circumferential direction of the tire, but like the former, this also has its limits due to the relationship with the vehicle body.

Third, the carcass structure is an attempt to reduce the rigidity of the tread area and ensure a good contact area with the road surface.

This last attempt was achieved by making the angle of the carcass ply cord larger with respect to the tire equatorial plane, so it has been successful in terms of ground contact area. However, the angle of the carcass ply cord Since the ply cord is thick in the direction, the effect of restraining the tread in the circumferential direction by the ply cord is reduced, and the centrifugal force during high-speed running causes the central area of the tread to protrude (bulge), which is unfavorable from the viewpoint of durability. Due to the decrease in lateral rigidity of the tread, the tread tends to become unstable in response to external forces when turning.Moreover, when driving straight, the combination of the bulge of the tread due to the centrifugal force and the low lateral rigidity poses a risk of causing a standing unibbed phenomenon. 0 The purpose of this invention is to significantly improve the running performance required of this type of tire, mainly by improving the structure of the tire side part, without increasing or decreasing the outer diameter or shape of the tire compared to the conventional tire. It is something to do.

In order to achieve this object, the present invention includes a pair of bead portions each having an annular bead wire, a pair of side portions connected to each bead portion, and a cylindrical tread portion extending between each side portion. comprising at least two ply fiber cord layers between the fiber cord layers, reinforced with a carcass in which the fiber cords are arranged crosswise to each other, and each end of the carcass is wound around a bead wire to form a carcass ply fold; An ultra-flat tire with a ratio of the cross-sectional height of the tire measured from the base of the bead to the maximum cross-sectional width of the tire in the range of 0.25 to 0.75 when assembled on a standard rim with a width approximately equal to or wider than the tread width. In a high-speed pneumatic tire, a metal cord is inserted between the carcass and the carcass ply folds from near the bead wire toward the radially outer end of the carcass ply folds in a range of 45° to 70° with respect to the radial direction of the tire. one metal cord layer arranged in a row, and a hard rubber filler closely integrated with the metal cord layer on the side surface, and
The outer edge of the metal cord layer in the radial direction is 0 of the tire cross-sectional height.
．． It is positioned within the range of 5 to 0.9.

The present invention will be explained below based on the drawings.

The drawings are diagrams showing one embodiment of the invention.

First, to explain the configuration, the tire 1 has a pair of left and right bead portions 3, 3 having a pair of left and right annular bead wires 22'.
', a pair of left and right side parts 4, 4' that are connected to the bead parts 3, 3' and extend outward in the radial direction, and both side parts 4, 4'.
It includes a wide cylindrical tread portion 5 spanning between the two.

A carcass 6 is provided between both bead wires 2, 2' to reinforce the rubber material of the tire 1.

This carcass 6 has at least two plies of fiber cord layers 7.
, 8, each cord layer 7° 8 is made of synthetic fibers such as nylon and polyester, and natural fibers, and the cords of the overlapping fiber cord layers 7 and 8 have an angle at which they intersect with each other and an equatorial plane E of the tire 1. and an angle of 20° to 40°.

This fiber cord layer 78 consists of an even number of plies, and 2 or 4 plies are preferably applied depending on the strength and elastic modulus of the fiber cord.

Both ends of the carcass 6 surround the bead wire 22'! It has carcass ply folds 9, 9' rolled up.

The outer ends of the carcass ply folds 9, 9' in the radial direction are located at the 100th point of the cross-sectional height H (assuming that the IJ is filled with internal pressure) measured from the base of the bead parts 3, 3' to the top of the tread part 5. to the tread portion 5, preferably disposed near the tread portion 5, and the radially outer end 11a of the inner fiber cord layer 11 is radially inner than the radially outer end 10a of the outer fiber cord layer 10. It is designed to be located in

This tire 1 has a ratio HE of cross-sectional height H and maximum cross-sectional width W.
W 1 That is, the aspect ratio is 0.25 to 0
．． It is an ultra-flat tire in the 75 range.

From above the bead wire 22' between the carcass 6 and the carcass ply folds 9, 9',
A metal cord layer 12.12', made of, for example, a steel cord, and a hard rubber filler 13.13' are provided towards the radially outer end of 9'.

The metal code layers 12, 12' may be two layers, and in this case, it is preferable that the metal codes of each layer intersect.

The metal cords of the metal cord layers 12, 12' are arranged in a range of 45° to 70° with respect to the radial direction of the tire 1, and intersect with the fiber cords of the fiber cord layer of the carcass 6 adjacent thereto.

This metal cord layer 12.12' has its entire one side in close contact with the carcass 6, and its radially inner end is connected to the bead wire 2.
, 2', and its radially outer end is located within a range of 0.5 to 0.9 of the cross-sectional height H, preferably within a range of 0.6 to 0.8.

In this case, the radial outer ends of the metal cord layers 12, 12' should not exceed the radial outer ends of the carcass ply folds 9, 9'.

On the other hand, the hard rubber filler 1313' has an elongated triangular cross section, and its base portion is adjacent to the bead wires 2, 2', and the other two side portions face the metal cord layers 12, 12' and the carcass ply folding 99'. And the pinnacle of that is Thailand? It is located radially inward from the maximum width position of the layer 1.

The hard rubber fillers 13 and 13' have a Shore A hardness of 60° or more, preferably in the range of 85° to 95°.

Describe below the results of tests conducted on a prototype high-speed pneumatic tire configured as described above.

The front tire size is l 1.5/21.5-15, the rear tire size is l 1.5/25.0-15,
The fiber cord layer that makes up the carcass has 4 plies, and the fiber cord that makes up the fiber cord layer is made of nylon 840 d.
/2. The angle with respect to the equatorial plane of the tire was 3 cf, and the fiber cords of each fiber cord layer were crossed with each other.

The radial outer ends of the carcass ply folds are arranged near the trend, and the radial outer ends of the inner fiber cord layers are stepped in a step-like manner so that they are located radially inward than the radial outer ends of the outer fiber cord layers. It is located.

The aspect ratio of the front tire is 0.3, the aspect ratio of the rear tire is 0.5, the shore A hardness of the hard rubber filler is 80°, and the apex is at a position of 0.4 of the cross-sectional height H of the tire. did.

The metal cord of the metal cord layer was made of steel and made into a single layer.

Its radially inner end is brought close to the radially outer end surface of the bead wire, its radially outer end is at a position of 0.7 of the cross-sectional height H of the tire, and its metal cord is 3
The cords were arranged at an angle of 0° to cross the cords of the fiber cord layer of the adjacent carcass, and the whole was brought into close contact with the carcass.

The outer surface of the tread portion was made smooth. The internal pressure of the front and rear tires was set to 2.0 kg/cr7r.

The vehicle used was GMH's TRANA (5,000CC),
Test course at CALDER in Australia (1
The test was conducted on a dry Tako road surface on a sunny day with a lap of 1.61 km).

The test results, namely rough time and driver feeling, are as follows.

This test result is a comparison between a tire of the present invention containing a metal cord layer and a tire (comparative example) under exactly the same conditions as the tire of the present invention except that only the metal cord layer was removed.

However, A has the best driver feeling, C has the worst driver feeling, and B has a driver feeling in between.

What is understood from the above is that the tire of the present invention is superior in high-speed running performance such as steering stability, acceleration/braking characteristics, and high-speed durability, compared to the tire of the comparative example.

Note that similar high-speed running performance was obtained even when the following metal code layer was used in place of the metal code layer described above.

That is, the radially outward portion of the metal cord layer extends radially outwardly beyond the radially outer end of the hard rubber filler;
The radially inner portion of the metal cord layer that is in close contact with the carcass is inserted between the carcass ply fold and the hard rubber filler.

[Brief explanation of the drawing]

The accompanying drawing is a sectional view of a high-speed pneumatic tire according to an embodiment of the present invention. 1... Tire, 2, 2'... Annular bead wire, 3.3'... Bead portion, 4, 4'...
... Side part, 5 ... Cylindrical tread part, 6 ... Carcass, 7, 8 ... Fiber cord layer, 9, 9' ...・Carcass ply folding,
12, 12'... Metal cord layer, 13, 13
'...Hard rubber filler.

Claims (1)

[Scope of Claims] 1. A tread comprising: a pair of bead portions provided with annular bead wires, a pair of side portions continuous to each bead portion, and a cylindrical tread portion extending between the side portions, and at least a portion between the bead wires. The carcass is composed of two ply fiber cord layers, and the fiber cords are reinforced with a carcass in which the fiber cords are arranged crosswise with each other between these fiber cord layers, and each end of the carcass is wound around a bead wire to form a carcass ply fold. The ratio of the tire cross-sectional height measured from the base of the bead to the tire's maximum cross-sectional width is 0.25 to 0.75 when assembled on a standard rim with a width approximately equal to or wider than the tread width.
In an ultra-flat high-speed pneumatic tire having a range of One metal cord layer arranged in the range of 70 degrees and a hard rubber filler closely integrated with this on the side surface, and the outer end of the metal cord layer in the radial direction is at the cross-sectional height of the tire. A high-speed running pneumatic tire characterized by having a diameter within a range of 0.5 to 0.9. 2. The high-speed running pneumatic tire according to claim 1, wherein the metal cords of the metal cord layer and the fiber cords of the fiber cord layer of the carcass adjacent thereto intersect with each other. 3. The high-speed running pneumatic tire according to claim 1 or 2, wherein the entire metal cord layer is disposed in close contact with the carcass. 4. A radially outer portion of the metal cord layer extends radially outward beyond the radially outer end of the rubber filler and is in close contact with the carcass, and a radially inner portion of the metal cord layer connects the carcass ply fold and the hard rubber filler. A high-speed running pneumatic tire according to claim 1 or 2, characterized in that the tire is sandwiched between a rubber filler and a rubber filler. 5. The high-speed pneumatic tire according to any one of claims 1 to 4, characterized in that the outer end in the radial direction of the folded carcass ply is located near the tread portion. .