JP2889283B2 - High performance pneumatic tire - Google Patents

Description

Description: TECHNICAL FIELD The present invention relates to a high-performance pneumatic tire capable of running at high speed.

[Prior Art] Conventionally, as a pneumatic tire having a tread rubber composed of two rubber layers, for example, a pneumatic tire described in JP-A-60-131303 is known. This is provided with a carcass layer, a belt layer arranged radially outside the carcass layer, and a tread rubber arranged radially outside the belt layer, and the tread rubber is made of a wear-resistant outer rubber layer. And a high resilience inner rubber layer, and the value obtained by dividing the thickness of the inner rubber layer by the thickness of the tread rubber is gradually increased from the tire equatorial plane toward the shoulder.

[Problems to be Solved by the Invention] In such a conventional pneumatic tire, the separation resistance at the end of the belt layer can be improved to some extent. Since pneumatic tires having high performance, that is, capable of running for a long period of time at high speed have been desired, such conventional pneumatic tires have become insufficient.

An object of the present invention is to provide a high-performance pneumatic tire that can effectively suppress separation by reducing heat generation in both shoulder portions.

[Means for Solving the Problems] An object of the present invention is to provide a carcass layer, a belt layer disposed radially outside of the carcass layer, and at least both ends of the belt layer in the axial direction to be substantially parallel to the tire equatorial plane. An auxiliary layer made of an organic fiber cord, and a tread rubber disposed radially outside of the belt layer and the auxiliary layer, wherein the tread rubber is an outer rubber layer, and the inner rubber has a lower heat generation than the outer rubber layer. A high-performance pneumatic tire having a thickness obtained by dividing the thickness of the inner rubber layer by the thickness of the tread rubber and gradually increasing from the tire equatorial plane toward the shoulder. This can be achieved by gradually decreasing the height from the equatorial plane of the tire toward the shoulder.

[Operation] In the present invention, the thickness of the tread rubber, that is, the total thickness of the inner and outer rubber layers is gradually reduced from the tire equatorial plane toward the shoulder. As a result,
The amount of rubber in the shoulder portion where the ends of the belt layer and the auxiliary layer are located is reduced, and therefore, even when running at high speed, the amount of heat generated in the shoulder portion is small, and the separation at the ends of the belt layer and the auxiliary layer is reduced. It is suppressed. In addition, since the thickness of the tread rubber in the shoulder portion is reduced, the heat dissipation is improved, and as a result, a rise in temperature in the shoulder portion is prevented, and the separation is further suppressed.

Hereinafter, an embodiment of the present invention will be described with reference to the drawings.

In FIG. 1, reference numeral 1 denotes a high-performance pneumatic tire capable of running at a speed of 200 to 350 km / h. The tire 1 has a ratio of the maximum width of the tire section to the height of the tire section (flat ratio) in the range of 0.5 to 0.3. Is a super-flat tire. In this embodiment, the tire 1 has a size of 255 /
40ZR17 tires (tires with an aspect ratio of 0.4) are used. The tire 1 is reinforced by a carcass layer 3 having a toroidal shape from one bead ring 2 to the other bead ring, and both side portions of the carcass layer 3 are arranged around the bead ring 2 from the inside in the axial direction. It is wound up toward the outside in the direction. This carcass layer 3 has at least one
And no more than three carcass plies 4 are laminated, and each carcass ply 4 extends in a substantially radial direction in each carcass ply 4, that is, rayon, which intersects the tire equatorial plane E at substantially 90 degrees. Many fiber cords represented by polyester, nylon and the like are embedded. In this embodiment, the carcass layer 3 is formed by laminating two carcass plies 4 each having an embedded rayon cord of 1650d / 2. Reference numeral 5 denotes a rubber filler made of a hard rubber having a base end bonded to the outer surface of the bead ring 2.
Has a tapered shape extending radially outward from the bead ring 2 and having a smaller thickness toward the distal end.

A belt layer 10 is provided on a radially outer side of the carcass layer 3. The belt layer 10 has at least two belt plies 11, 12 in which a non-extensible cord represented by steel is embedded. In this example, two sheets are stacked. The cords respectively embedded in the belt plies 11 and 12 are inclined so as to intersect at an angle of 15 to 35 degrees with respect to the tire equatorial plane E, and are opposite to each other between the belt plies 11 and 12. Inclined and interlaced. In this embodiment, the belt ply 11 and the belt ply 12 intersect at an angle of 22 degrees with the tire equatorial plane E at 1 ×.
Many 5 steel cords are buried.

Reference numeral 16 denotes an auxiliary layer that covers at least both ends in the axial direction of the belt layer 10.The auxiliary layer 16 may slightly protrude outward from both ends in the axial direction of the belt layer 10 as in this embodiment. The entire layer 10 may be covered. The auxiliary layer 16 is formed by laminating at least one auxiliary ply, that is, a rubberized cord (cord composed of 66 nylon in this embodiment) made of a heat-shrinkable organic fiber represented by a nylon cord. Is a wide (260 mm width) first auxiliary ply 17 disposed on the inside, a middle auxiliary width (90 mm width) second auxiliary ply 18 disposed on the center, and a narrow (30 mm width) disposed on the outside. The third auxiliary ply 19 and the three auxiliary plies are laminated, and the cords in the first, second, and third auxiliary plies 17, 18, and 19 are substantially parallel to the tire equatorial plane E. Are arranged. These auxiliary plies 1
7, 18, 19, after arranging a plurality of (2 to 15) cords in parallel, these cords are rubberized to form a ribbon having a width of 5 to 10 mm, and the ribbon is spirally formed. It is formed by winding. Both outer ends of the belt layer 10 and the auxiliary layer 16 in the axial direction are respectively located on the shoulder portions S of the tire 1.

A tread rubber 26 having a cylindrical shape is disposed radially outside the belt layer 10 and the auxiliary layer 16, and a plurality of well-known circumferential grooves (not shown) are arranged on the outer periphery of the tread rubber 26. A plurality of lateral grooves extending in a direction intersecting these grooves are formed. The tread rubber 26 is composed of an outer rubber layer 27 located radially outward and an inner rubber layer 28 located radially inward. The outer rubber layer 27 is a rubber having good wear resistance and wettability, while the inner rubber layer 28 is composed of a rubber having a lower heat generation than the outer rubber layer 27, that is, a rubber having a rebound resilience coefficient of 30% or more. Have been. Further, the thickness F of the tread rubber 26, that is, the total thickness of the thickness G of the outer rubber layer 27 and the thickness H of the inner rubber layer 28 decreases almost gradually from the tire equatorial plane E toward the shoulder S. ing. As a result, the belt layer 10 and the auxiliary layer
The amount of rubber at the end of 16 is reduced, the calorific value is reduced, and the heat dissipation is improved.
In addition, the temperature rise at the end of the auxiliary layer 16 is prevented, and the separation is suppressed. Here, the thickness F,
Each of G and H is a value measured by making a perpendicular line to the belt layer 10 or the auxiliary layer 16 in the land portion divided by the groove and along the perpendicular line. If the thickness of the tread rubber 26 on the tire equatorial plane E is Fa, the tire equatorial plane E
The thickness Fb of the tread rubber 26 at a point separated by 1/4 of the tread width is in the range of 0.6 to 1.0 times the Fa,
Further, the thickness Fc of the tread rubber 26 at the shoulder portion is preferably in the range of 0.2 to 0.6 times the above Fa.
In this embodiment, the thickness Fa is 10 mm, and the thickness Fb is 9 mm (0.9 F
a), Fc is 5 mm (0.5 Fa). In addition, the inner rubber layer 28
The value obtained by dividing the thickness H of the tire by the thickness F of the tread rubber 26 gradually increases from the tire equatorial plane E toward the shoulder S. As a result, the ratio of the inner rubber layer 28 to the tread rubber 26 is maximum at the shoulder portion S, but since the inner rubber layer 28 is a low heat-generating rubber, the amount of heat generated at the shoulder portion S is reduced, Separation is further suppressed. Here, contrary to the above, the value is set to the shoulder S
In general, such a high-performance pneumatic tire wears at the center portion prior to the shoulder portion, so that the inner rubber layer 28 is exposed at the center portion to deteriorate wet performance, or , Outer rubber layer 27
May be missed and chunk out may occur. The value obtained by dividing the thickness H by the thickness F is
It is in the range of 0.05 to 0.25 on the tire equatorial plane E, and at a point separated from the tire equatorial plane E by 1/4 of the tread width,
It is preferably in the range of 0.10 to 0.30, and in the shoulder portion S, it is preferably in the range of 0.30 to 1.0. Further, the value in the shoulder portion S is more preferably 0.50 or more. In this embodiment, on the tire equatorial plane E, the thickness Fa is 10 mm, and the thickness Ha of the inner rubber layer 28 is 1 mm. Therefore, the value is 0.10, and the thickness at a point separated by 1/4 of the tread width is obtained. Since Fb is 9 mm and thickness Hb is 1.2 mm, the value is 0.13, and the thickness Fc at the shoulder S is
Since the thickness Hc is 5 mm and the thickness Hc is 3 mm, the value is 0.60. Then, as described above, the thickness H of the inner rubber layer 28 is
If the value divided by the thickness F of the tire 26 gradually increases from the tire equatorial plane E toward the shoulder S, the thickness H of the inner rubber layer 28 increases toward the shoulder S, and at the shoulder S, Will be the largest. Where the inner rubber layer
28, the thickness Ha is in the range of 0.5 mm to 2 mm on the tire equatorial plane E, and the thickness Hb is in the range of 0.5 mm to 2.5 mm at a point separated from the tire equatorial plane E by 1/4 of the tread width. Yes, and
It is preferable that the thickness Hc of the shoulder S is in the range of 1 to 4 mm. In this embodiment, the outer rubber layer 27,
The inner rubber layer 28 is made of a single rubber, but may be made of a plurality of types of rubber having different characteristics according to the required characteristics of the tire 1. The increase in the thickness of the inner rubber layer 28 from the tire equatorial plane E to the shoulder portion S can be increased stepwise in addition to the literally increasing mode.

Next, test examples will be described. In this test, the test tire of the above example to which the present invention was applied and the inner rubber layer in the test tire were formed into a 1 mm rubber sheet having a uniform thickness, and were the same as other test tires. And tires. Then, mounted on a passenger car after filling the inner pressure of 2.0 kg / cm ² in each tire, 50 courses diameter circle 1km at a speed of 200km
After running for 00 km continuously, no chunkout occurred in both tires, and there was no difference between the two tires. next,
Each tire worn in the test is pressed against a high-speed drum while applying a load of 500 kg, and after initially running for 10 minutes at 100 km / h, the speed is increased by 10 km every 10 minutes to a final speed of 370 km, The high-speed durability of the tire was measured. When the results are shown in exponential notation, the comparative tires
However, the test tire had an excellent high-speed durability of 130, which was excellent. Here, the index 100 is 280 per hour
It was durable up to km.

[Effects of the Invention] As described above, according to the present invention, heat generation at both shoulder portions can be reduced, and separation can be effectively suppressed.

[Brief description of the drawings]

FIG. 1 is a meridional section of a tire showing one embodiment of the present invention. 1: high performance pneumatic tire, 3: carcass layer, 10: belt layer, 16: auxiliary layer, 26: tread rubber, 27: outer rubber layer, 28: inner rubber layer, E: tire equatorial plane, F: tread rubber Thickness, S: shoulder part, H: thickness of inner rubber layer

Claims (1)

(57) [Claims] 1. A carcass layer, a belt layer disposed radially outside of the carcass layer, and an auxiliary layer comprising an organic fiber cord covering at least both axial ends of the belt layer and substantially parallel to the tire equatorial plane. A tread rubber disposed radially outside of the belt layer and the auxiliary layer, the tread rubber comprising: an outer rubber layer; and an inner rubber layer having a lower heat generation than the outer rubber layer. In a high-performance pneumatic tire in which the value obtained by dividing the thickness of the rubber layer by the thickness of the tread rubber gradually increases from the tire equatorial plane toward the shoulder, the thickness of the tread rubber moves from the tire equatorial plane to the shoulder. A high-performance pneumatic tire characterized by gradually decreasing in accordance with the following.