JPH0382604A - High-performance pneumatic radial tire - Google Patents

Abstract

PURPOSE:To allow extremely high speed running and suppress the biased abrasion of land sections by forming an auxiliary layer with multiple auxiliary plies, and cutting the outermost auxiliary ply among auxiliary plies having portions overlapped on the land sections of a tread section at overlapped portions. CONSTITUTION:Auxiliary layers 16 are arranged on the outside in the radial direction of belt layers 10 of a tire 1, and a tread ribber 17 is arranged on the outside in the radial direction of them. Multiple peripheral main grooves 18 are formed on the outer surface of the tread rubber 17 to form multiple land sections 19. Auxiliary layers 16 are formed with multiple auxiliary plies 21 and 22, and heat contraction organic fiber cords are arranged in parallel with a tire equatorial plane E in them. The outermost auxiliary ply 22 among auxiliary plies having portions overlapped with peripheral main grooves 18 is cut at portions overlapped with multiple peripheral main grooves 18a-18c.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a high performance pneumatic radial tire capable of running at ultra high speeds.

Conventionally, high-performance pneumatic radial tires consist of a carcass layer, a belt layer disposed radially outside the carcass layer, and at least one auxiliary ply covering both axial ends of the belt layer. an auxiliary layer in which organic fiber cords substantially parallel to the tire equatorial plane are embedded, and a tread rubber disposed radially outward of the belt layer and the auxiliary layer, the outer surface of the tread rubber having at least 2
Tires are known in which land portions are defined between the circumferential main grooves and between the circumferential main grooves and the tread ends by forming circumferential main grooves.

However, although such tires are capable of running at a certain level of high speed, when running at ultra-high speeds, such as 200 to 300 km/h, which have been required in recent years, the land area with a large mass expands greatly outward in the radial direction due to centrifugal force. and blow out, thereby tearing off the land area,
There is a problem that so-called chunk-out occurs.

In order to solve these problems, the auxiliary layer consists of one auxiliary ply that is placed on the innermost side and covers the entire width of the belt layer, and one auxiliary ply that is placed on the outside of this innermost auxiliary ply that covers the entire width of the belt layer. Consisting of one or more auxiliary plies that span or cover both ends of the belt layer in the axial direction, that is, two or more auxiliary plies in total, to effectively prevent the land portion from bulging due to centrifugal force. something is proposed.

However, in such tires, the auxiliary layer is composed of a total of two or more auxiliary plies, so the thickness of the auxiliary layer itself becomes thick, and as a result, the thickness of the vulcanization mold for forming the circumferential main groove increases. The distance between the protrusion and the outermost auxiliary ply becomes narrower at the end of vulcanization. For this reason, the auxiliary layer and the belt layer at the portions overlapping the circumferential main groove are pushed radially inward by the projections of the vulcanization mold and are recessed, causing the auxiliary layer and the belt layer to become wavy as a whole. When internal pressure is applied to a tire with such wavy auxiliary layer and belt layer, the auxiliary layer and belt layer are extended and deformed to become flat.
This deformation affects the surrounding land areas, resulting in uneven ground pressure on the land areas and uneven wear. Moreover, when the thickness of the auxiliary layer itself is thick as described above, when the circumferential main groove is molded into the tread rubber by vulcanization, the distance between the groove bottom of the circumferential main groove and the auxiliary layer is In other words, if the base gauge becomes thinner and as a result cracks, cuts, etc. occur at the bottom of the main groove in the circumferential direction, moisture may reach the auxiliary layer or belt layer and damage these auxiliary and belt layers. There are also problems.

An object of the present invention is to provide a high-performance pneumatic radial tire that is capable of suppressing uneven wear occurring on the land portion and ensuring a base gauge of the required thickness while enabling ultra-high speed running.

Therefore, such a purpose is to configure the auxiliary layer from two or more auxiliary plies, including one auxiliary ply that is disposed on the innermost side and covers the entire width of the belt layer, and a portion that overlaps the circumferential main groove. This can be achieved by dividing at least the outermost auxiliary ply of the auxiliary ply having the above-mentioned auxiliary ply at a portion overlapping the circumferential main groove.

In this invention, the auxiliary layer is composed of two or more auxiliary plies, including one auxiliary ply that is disposed at the innermost side and covers the entire width of the belt layer. As a result, even if a land area with a large mass is subjected to a large centrifugal force due to high-speed rotation of the tire, at least the innermost auxiliary ply, and in areas where two or more auxiliary plies overlap, these two or more auxiliary plies , any land portion is restricted from bulging outward in the radial direction, and as a result, chunk-out is prevented from occurring. In addition, in this invention, since the auxiliary layer is composed of two or more auxiliary plies, the thickness of the auxiliary layer itself is increased, but at least the most The outer auxiliary ply was divided at the region where it overlapped with the circumferential main groove, and the divided region was filled with tread rubber. As a result, the protrusions of the vulcanization mold for forming the main groove in the circumferential direction will face the auxiliary ply on the inside of the divided auxiliary ply during vulcanization, and the distance between them at the end of vulcanization will be It becomes wider. For this reason, the influence of the protrusions of the vulcanization mold on the auxiliary layer and the belt layer is reduced, and the amount of depression in the auxiliary layer and the belt layer is reduced. Therefore, even when the tire of the present invention is filled with internal pressure and then driven, the ground contact pressure on the land portion is almost uniform, and uneven wear is suppressed. In addition, as mentioned above, at the end of vulcanization, the distance between the protrusion of the vulcanization mold, that is, the groove bottom of the circumferential main groove, and the auxiliary ply becomes wider, so there is a need for a rubber of the required thickness to be placed between them, that is, the base. Gauge can be secured.

1. A first embodiment of the present invention will be described below with reference to the drawings.

In FIG. 1, 1 is a high-performance pneumatic radial tire that can run at +s at 200 to 300 per hour, and this tire 1 has a ratio of the maximum tire cross-sectional width to the tire cross-sectional height (flatness ratio) of 0. It is a tire with an ultra-flat shape ranging from 5 to 0.3. In this example,
A tire with a size of 255/40ZR17 (tire with an aspect ratio of 0.4) is used as the tire l. The tire 1 is reinforced with a toroidal carcass layer 3 extending from one bead ring 2 to the other bead ring, and both sides of the carcass layer 3 are covered with the bead ring 2 and a bead filler 4 made of hard rubber. It is wound up from the axially inner side to the axially outer side.

This carcass layer 3 has at least one layer, in this embodiment two layers.
In this example, it is constructed by laminating several carcass plies 5.6, and in each carcass ply 5.6 there is a fiber cord extending approximately in the radial direction, i.e. intersecting at approximately 90 degrees with respect to the tire equatorial plane E. A large number of 1650 d/2 Rayon cords are buried there.

A belt layer 10 is arranged radially outside the carcass layer 3, and this belt layer 10 includes belt plies 11, 12 in which non-stretchable cords typically made of steel are embedded.
It is constructed by laminating at least two sheets, in this example, two sheets. And these belt plies 11.
The cords embedded in each of the belt plies 11 and 12 are inclined so as to intersect with the tire equatorial plane E at an angle of 15 degrees to 35 degrees, and are inclined in opposite directions and intersect with each other between the belt plies 11 and 12. In this embodiment, two belt plies 11 and 12 are provided with respect to the tire equatorial plane E.
A large number of IX5 steel cords intersecting at 5 degree angles are buried.

Reference numeral 16 denotes an auxiliary layer disposed on the radially outer side of the belt layer 10, and a tread rubber 17 is disposed on the radially outer side of the auxiliary layer 16 and the belt layer 10. At least two wide circumferential main grooves 18 are formed on the outer surface of the tread rubber 17, and in this embodiment,
Three grooves are formed on each side with the tire equatorial plane E as a plane of symmetry, and these circumferential main grooves 18 are spaced approximately equal distance apart in the axial direction. As a result, land portions 19 extending in the circumferential direction are defined between these 18 circumferential main grooves and the outermost circumferential main groove 18 and the tread end T, respectively. In this embodiment, each land portion 19 is divided into blocks by a plurality of lateral grooves (not shown) extending in the axial direction and spaced apart from each other in the circumferential direction. Further, in this embodiment, a circumferential minor groove 20 having a groove width slightly narrower than the circumferential major groove 18 is also formed on the tire equatorial plane E. The groove width and groove depth of the circumferential and directional main grooves 18 are each 10+
wm, 8mm, and the groove width and groove depth of the circumferential minor groove 20 are 5+sm and 6ram, respectively.

The auxiliary layer 16 has a heat-shrinkable organic fiber cord represented by a nylon cord (1280 d in this embodiment) inside.
It is composed of two or more (two in this example) auxiliary plies 21.22 in which a cord made of 68 nylon of /2 is embedded, and the cords in these auxiliary plies 21.22 are They are arranged substantially in parallel. The auxiliary layer 16 has one auxiliary ply 21 on the innermost side that covers the entire width of the belt layer IO, and the auxiliary ply 21 on the radially outer side of the innermost auxiliary ply 21.
1, the auxiliary ply 22 is arranged to cover the entire width of the belt layer 10. As a result, even if the land portions 19 are subjected to a large centrifugal force due to the high speed rotation of the tire 1, these auxiliary plies 21, 22 strongly restrict the expansion of any of the land portions 19 to the outside in the radial direction. , the occurrence of chunk-out is reliably prevented. here.

As mentioned above, the auxiliary layer 16 is formed by two auxiliary plies 21 and 22.
In this embodiment, the outermost auxiliary ply among the auxiliary plies having a portion overlapping with the circumferential main groove 18 is
Here, the auxiliary ply 22 is connected to the circumferential main grooves 18a, b, c.
It is divided at the part where it overlaps. It should be noted that these divided parts may remain as spaces, but are filled with the tread rubber 17. When the auxiliary ply 22 is divided in this way, the protrusion of the vulcanization mold (for forming the circumferential main groove 18)
is the auxiliary ply 21 located inside the auxiliary ply 22
As a result, the distance between the protrusion of the vulcanization mold and the auxiliary ply 21 at the end of vulcanization is
The distance is wider than the distance between the auxiliary ply 22 and the auxiliary ply 22. Therefore, during vulcanization, the influence of the protrusions of the vulcanization mold on the auxiliary layer 1B and the belt layer 1O is small, and the amount of denting of these inward in the radial direction is reduced. As a result, this tire 1
Even when the vehicle is driven using the vehicle, the ground pressure of each ridge 18 is approximately uniform, and uneven wear is suppressed. Moreover, the required thickness between the groove bottom of the circumferential main groove 18 and the auxiliary ply 21 is generally 1.5 mm.
It is also possible to secure a base gauge G of mm.

Here, each of the above-mentioned auxiliary plies 21 and 22 has a plurality of pieces (
2~! After arranging 5 cords in parallel, these cords are rubberized to form a ribbon-like body with a width of 5 to 10 cm (10 to 30% of the width of the ridge 18), and this ribbon-like body is It is formed by winding it in a spiral.

FIG. 2 is a diagram showing a second embodiment of the invention. The feature of this embodiment is that one auxiliary ply 31 is further arranged on the outside in the radial direction of the two auxiliary plies 21 and 22 that cover the entire width of the belt layer 1o. It covers the axial end of the belt layer 10 from the tread end T to the circumferential main groove 18b. In this embodiment, this outermost auxiliary ply 31 is connected to the circumferential main groove 1.
8a, and the auxiliary ply 22 on the inner side of the auxiliary ply 31 is also divided at the portions that overlap the circumferential main grooves 18a, b, and c in the same manner as described above.

FIG. 3 is a diagram showing a third embodiment of the invention. The feature of this embodiment is that three auxiliary plies 32, 33, 34 are arranged radially outward of the two auxiliary plies 21, 22 that cover the entire width of the belt layer 10 from the radially inside to the outside. The auxiliary ply 32
is the belt layer l from the tread end T to the circumferential main groove 18c
Further, the auxiliary ply 33 covers the belt layer 10 from the tread end T to the circumferential main groove tab, and the auxiliary ply 34 covers the belt layer 1o from the tread end T to the circumferential main groove 18a. In this embodiment, the auxiliary ply 21.2 has a portion overlapping the circumferential main groove 18.
2.3 Of 2.33, not only the outermost auxiliary ply 33 but also the inner auxiliary ply 32.22 are tlIt in the circumferential direction.
It is divided at the part that overlaps I&. Note that the auxiliary ply 34 does not fit into the circumferential main groove 18 at any location.
Since they do not overlap, there is no dividing point.

FIG. 4 is a diagram showing a fourth embodiment of the present invention. The feature of this embodiment is that the belt layer IO explained in the first embodiment is
The auxiliary ply 22 that covers the entire width of the
The three auxiliary plies 32, 33, and 34 described in the embodiment are provided, and the auxiliary plies 32, 33 other than the auxiliary ply 34 are separated at the portions overlapping the circumferential main groove 18.

Next, a test example will be explained. In this test, the test tire of the first embodiment to which the present invention was applied and the test tire except that the outer auxiliary ply 22 in the test tire was continuous without being separated at any position. Comparative tires that are identical were prepared, and 2.5 kg was applied to each tire.
After filling with an internal pressure of /Cm'', it was pressed against a high-speed drum while applying a load of 500Kg, and the initial speed was 1100km/h.
After running at K for 10 minutes, the speed was increased by the amount of IOK every 10 minutes until each tire failed. The results show that both the comparison tire and the test tire were damaged at the same speed step, and it can be seen that the separation of the auxiliary ply has no effect on high-speed durability. After filling the internal pressure of CM'', it was installed in a passenger car and drove around a course with a circumference of 6 Kta at a speed of 150 mph and 500 mph with dust.
The tires were run continuously for 0 km, and then the difference between the amount of wear at the axial center of each tire block and the amount of wear at the outer edge of the block in the axial direction was measured. The results showed that the comparison tire had an average of 1.0 mm, but the test tire had an average of (13+ss), indicating that the test tire had better uneven wear resistance. .

In the above-described embodiment, the auxiliary plies 22, 31, 32.
33 (excluding the inner auxiliary bly 21) were all separated at the region overlapping the circumferential main groove 18, but in the present invention, at least only the outermost auxiliary ply among the auxiliary plies is separated. In addition, in the present invention, all the auxiliary briars including the innermost auxiliary briar 21 may be divided at the portions overlapping the circumferential main grooves 18.

As explained above, according to this invention, it is possible to suppress uneven wear that occurs on the land part while enabling ultra-high speed running, and it is also possible to ensure a base gauge of the required thickness. can.

[Brief explanation of drawings]

FIG. 1 is a meridian sectional view of a tire showing a first embodiment of the invention, FIG. 2 is a meridian sectional view of a tire showing a second embodiment of the invention, and FIG. 3 is a meridian sectional view of a tire showing a third embodiment of the invention. FIG. 4 is a meridian sectional view of a tire showing a fourth embodiment of the present invention. 1... High performance air filled 3... Carcass layer 16... Auxiliary layer 18... Circumferential main grooves 21, 22... Auxiliary ply T... Tread end

Claims (1)

[Claims] a carcass layer, a belt layer disposed radially outward of the carcass layer, an auxiliary layer disposed radially outward of the belt layer and embedded with organic fiber cords substantially parallel to the tire equatorial plane, a belt layer and an auxiliary layer; tread rubber disposed on the radially outer side of the layer, and at least two circumferential main grooves are formed on the outer surface of the tread rubber,
In a high-performance pneumatic radial tire in which a land portion is defined between the circumferential main grooves and between the circumferential main groove and the tread edge, the auxiliary layer is disposed on the innermost side and the belt layer covers the entire width. Consisting of two or more auxiliary plies including one auxiliary ply that covers the whole area, at least the outermost auxiliary ply of the auxiliary plies having a portion that overlaps the circumferential main groove overlaps the circumferential main groove. A high-performance pneumatic radial tire that is characterized by being separated at certain points.