JP2008030506A - Pneumatic tire - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a pneumatic tire improved in cornering performance by using an aliphatic poly-ketone fiber cord for one of reinforcing cords of a belt layer. <P>SOLUTION: The pneumatic tire designating an installing direction against a vehicle is constituted so that the belt layer 7 has: a first belt layer 7A arranged adjacent to a carcass layer 4 and burying a steel cord (s) inclined and arranged in one direction against a tire circumferential direction TC in a rubber layer (r); a second belt layer 7B arranged on the outer peripheral side of the first belt layer 7A and burying the aliphatic poly-ketone fiber cord (f) inclined and arranged in the other direction against the tire circumferential direction TC in the rubber layer (r); and a third belt layer 7C arranged on the side of a vehicle installing outside region on the outer peripheral side of the second belt layer 7B and burying the aliphatic poly-ketone fiber cord (f) inclined and arranged in the other direction against the tire circumferential direction TC in the rubber layer (r). <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

The present invention relates to a pneumatic tire, and more particularly, to a pneumatic tire capable of improving cornering performance.

In the pneumatic tires for passenger cars, tires that use aramid fiber cords with high elastic modulus instead of steel cords as one of the reinforcement cords of the two belt layers are known to improve ride comfort and reduce weight. It has been. However, since aramid fiber cords have low adhesion to rubber and are also poor in fatigue resistance, tires that use aramid fiber cords as one of the reinforcing cords in the two belt layers have improved belt durability. There was room.

Therefore, as a countermeasure, a pneumatic tire using an aliphatic polyketone fiber cord as one reinforcing cord of the two belt layers has been proposed (see, for example, Patent Document 1). Since the aliphatic polyketone fiber cord is excellent in adhesiveness to rubber, it is possible to obtain high high-speed durability while improving ride comfort and reducing weight.

By the way, in recent years, the safety consciousness in the market has increased, and a pneumatic tire with higher safety has been demanded. The above-described pneumatic tire is no exception.
JP 2001-341505 A

An object of the present invention is to provide a pneumatic tire that can improve cornering performance in a pneumatic tire using an aliphatic polyketone fiber cord as one reinforcing cord of a belt layer.

The pneumatic tire of the present invention that achieves the above object is a pneumatic tire in which a carcass layer is extended between the left and right bead portions, a plurality of belt layers are provided on the outer periphery side of the carcass layer of the tread portion, and the mounting direction with respect to the vehicle is designated. In the tire, a first belt layer in which the plurality of belt layers are arranged adjacent to the carcass layer and steel cords that are inclined in one direction with respect to the tire circumferential direction are embedded in a rubber layer, and the first belt A second belt layer in which an aliphatic polyketone fiber cord disposed on the outer peripheral side of the layer and arranged obliquely in the other direction with respect to the tire circumferential direction is embedded in the rubber layer, and a vehicle-mounted outer region on the outer peripheral side of the second belt layer It is characterized by having a third belt layer that is disposed on the side and in which an aliphatic polyketone fiber cord that is inclined and arranged in the other direction with respect to the tire circumferential direction is embedded in a rubber layer.

According to the above-described present invention, the third belt layer in which aliphatic polyketone fiber cords are inclinedly arranged is arranged on the vehicle mounting outer region side on the outer peripheral side of the first and second belt layers. Since the rigidity can be increased and the cornering power can be increased, the cornering performance can be improved.

Further, since it is only necessary to dispose the third belt layer on the vehicle mounting outer region side, a significant increase in weight can be avoided, and the aliphatic polyketone fiber cord of the third belt layer can be used as the fat of the second belt layer. Inclination in the same direction as the aliphatic polyketone fiber cord suppresses shear strain between the layers, while lowering the rigidity step on the left and right of the belt layer group using the aliphatic polyketone fiber cord, Generation of separation between the three belt layers can be prevented.

Hereinafter, embodiments of the present invention will be described in detail with reference to the accompanying drawings.
FIG. 1 shows an embodiment of the pneumatic tire of the present invention, wherein 1 is a tread portion, 2 is a sidewall portion, 3 is a bead portion, and CL is a tire center line. This pneumatic tire has a specified mounting direction with respect to the vehicle, and is mounted on the vehicle so that the right side of the tire center line CL is outside the vehicle when the vehicle is mounted, and the right side of the tire center line CL is on the vehicle mounting outside region O. The left side is the vehicle mounting inner area I.

Between the left and right bead portions 3, a carcass layer 4 in which reinforcing cords made of organic fiber cords such as polyester extending in the tire radial direction are arranged at predetermined intervals along the tire circumferential direction is extended, and both ends thereof Is folded back from the inside to the outside of the tire so as to sandwich the bead filler 6 around the bead core 5 embedded in the bead portion 3. A plurality of belt layers 7 are provided on the outer peripheral side of the carcass layer 4 of the tread portion 1. On the outer peripheral side of the plurality of belt layers 7, a belt cover layer 8 is provided in which a rubber-coated nylon cord is spirally wound at substantially 0 ° in the tire circumferential direction.

The plurality of belt layers 7 include a first belt layer 7A disposed adjacent to the carcass layer 4, a second belt layer 7B disposed adjacent to the outer peripheral side of the first belt layer 7A, and the first belt layer 7A. It is comprised from the 3rd belt layer 7C arrange | positioned adjacent to the outer peripheral side of 2 belt layer 7B. As shown in FIG. 2, the first belt layer 7 </ b> A has a configuration in which steel cords (reinforcing cords) s inclined and arranged in one direction with respect to the tire circumferential direction TC are embedded in the rubber layer R <b> 1. Second belt layer 7B
Is configured by embedding an aliphatic polyketone fiber cord (reinforcing cord) f inclined and arranged in the other direction with respect to the tire circumferential direction TC in the rubber layer R2.

The two belt layers 7A and 7B are composed of a steel cord s and an aliphatic polyketone fiber cord f.
And the first belt layer 7A adjacent to the carcass layer 4 is more than the second belt layer 7B laminated on the outer peripheral side thereof. Even the belt width is wide.

The third belt layer 7C is disposed in the vehicle-mounted outer region O on the outer peripheral side of the second belt layer 7B, and uses the same aliphatic polyketone fiber cord f as the second belt layer 7B, and the tire circumferential direction T
Aliphatic polyketone fiber cords inclined with respect to C in the same other direction as the second belt layer 7B (
The reinforcing cord f is embedded in the rubber layer R3. The aliphatic polyketone fiber cords f of the third belt layer 7C are arranged at substantially equal intervals similarly to the second belt layer 7B.

According to the present invention described above, since the third belt layer 7C in which the aliphatic polyketone fiber cords f are arranged in an inclined manner on the vehicle mounting outer region O side on the outer peripheral side of the belt layers 7A and 7B, the third belt layer 7C is arranged in the vehicle mounting outer region O. Since the tread rigidity is increased, and the lateral force during cornering can be increased, the cornering performance can be improved.

Further, since the third belt layer 7C only needs to be disposed on the vehicle-mounted outer region O side, the weight is not increased significantly, and the aliphatic polyketone fiber cord f of the third belt layer 7C is attached to the second belt. Since the layer 7B is inclined in the same direction as the aliphatic polyketone fiber cord f, the belt layer 7B using the aliphatic polyketone fiber cord f, while suppressing shear strain between the layers,
The rigidity difference between the left and right sides of the 7C group can be lowered to prevent separation between the belt layers 7B and 7C during traveling.

In the embodiment of FIGS. 1 and 2 above, the third belt layer 7 </ b> C disposed in the vehicle mounting outer region O.
The width (width measured in parallel with the tire axis) W3 is in the range of 1/3 to 1/2 of the width (width measured in parallel with the tire axis) W2 of the second belt layer 7B. Is good. If the width W3 of the third belt layer 7C is narrower than 1/3 of the width W2 of the second belt layer 7B, the effect of improving the cornering performance is small, which is not preferable. Even if the width W3 of the third belt layer 7C is made larger than ½ of the width W2 of the second belt layer 7B, the effect of improving the cornering performance does not change much, and widening causes an unnecessary increase in weight.

The range in which the third belt layer 7C is disposed is preferably a range from the tire center line CL to the edge of the second belt layer 7B.

The strength of the aliphatic polyketone fiber used for the aliphatic polyketone fiber cord f of the second belt layer 7B and the third belt layer 7C is preferably 9 cN / dtex or more in order to ensure the belt strength. In addition, the intensity | strength of the fiber said here is measured based on JISL1017. The upper limit can be set to 17 cN / dtex or less due to manufacturing problems.

The steel cord s of the first belt layer 7A is composed of a stranded wire cord in which a plurality of strands are bundled and twisted, and the diameter of each strand constituting the steel cord s is 0.28 m.
It is good from the point of riding comfort to make it below m. As for the diameter of the strand, the thinner the better, the better the ride comfort. However, due to actual manufacturing problems, the lower limit of the strand diameter is about 0.10 mm.

FIG. 3 shows a main part in another embodiment of the pneumatic tire of the present invention. In this embodiment, the aliphatic polyketone fiber cord f of the third belt layer 7C is spirally wound and arranged so as to be inclined in the other direction with respect to the tire circumferential direction TC. The form is the same.

As shown in FIG. 4, an aliphatic polyketone fiber cord f covered with rubber x is spirally wound around the outer peripheral side of the second belt layer 7B, and the aliphatic polyketone fiber located on the vehicle-mounted inner side. The portion f of the aliphatic polyketone fiber cord positioned on the outer side of the vehicle where the cord portion fi
Winding is performed with a smaller winding interval than o. In order to alleviate the left and right rigidity steps, it is preferable to wind the aliphatic polyketone fiber cord f gradually toward the inner side of the vehicle as shown in FIG. Although it is preferable to use one aliphatic polyketone fiber cord f coated with rubber in this way, a plurality of rubber-coated aliphatic polyketone fiber cords f may be used instead.

As described above, the aliphatic polyketone fiber cord f of the third belt layer 7C is spirally wound, and the aliphatic polyketone fiber cord portion fi located on the vehicle mounting inner side is positioned on the vehicle mounting outer side. The same effect as described above can also be obtained by winding with the winding interval sparser than the portion fo of the cord f.

When the aliphatic polyketone fiber cord f is spirally wound as described above, the width W3 of the third belt layer 7C is set to 1/3 to 2/3 of the width W2 of the second belt layer 7B for the same reason as described above. be able to. The range in which the third belt layer 7C is disposed is preferably the range from the tire center line CL to the edge of the second belt layer 7B.
When the width W3 of the second belt layer 7B is wider than ½ of the width W2 of the second belt layer 7B, the sparse portion may extend from the tire center line CL to the vehicle mounting inner side.

The present invention can be preferably used particularly for a pneumatic tire for a passenger car, but is not limited thereto, and can also be applied to other pneumatic tires.

Tires 1 and 2 of the present invention in which the tire size is 225 / 60ZR16, the tire structure is the same as in FIG. 1 (where a block pattern is formed on the tread surface), and a belt layer having the configuration shown in Table 1 is provided.
(Examples 1 and 2), comparative tires (comparative examples), and conventional tires 1 and 2 (conventional examples 1 and 2) were produced as test tires, respectively. The strength of the aliphatic polyketone fiber used for the aliphatic polyketone fiber cord used in each test tire is 10 cN / dtex.

Each of these test tires was assembled on a standard rim, the air pressure was set to 230 kPa, and high speed durability, riding comfort, and cornering performance were evaluated by the following test methods. The results shown in Table 1 were obtained.

High Speed Durability Each test tire was wetted by leaving it in an atmosphere of 70 ° C. and 98% humidity for 30 days, and then attached to a drum testing machine, and was carried out in accordance with the high speed durability test described in JIS. . The results were evaluated in five grades, with the conventional tire 1 as a reference: ◎, ○, equivalent to reference, Δ, ×. Note that ◎ means a significant improvement, ○ means an improvement, △ means a decrease, and × means a significant deterioration.

Ride comfort Each test tire was mounted on a passenger car with a displacement of 3000 cc, and a sensory test was conducted by a test driver on the test course. The results were evaluated in five grades, with the conventional tire 1 as a reference: ◎, ○, equivalent to reference, Δ, ×. Note that ◎ means a significant improvement, ○ means an improvement, △ means a decrease, and × means a significant deterioration.

Cornering performance Each test tire is mounted on a passenger car with a displacement of 3000cc, and a sensory test is conducted by a test driver on the test course, and the results are classified into five levels: ◎, ○, standard equivalent, △, ×, based on the conventional tire 1. It was evaluated with. Note that ◎ means a significant improvement, ○ means an improvement, △ means a decrease, and × means a significant deterioration.

From Table 1, it can be seen that the present invention can improve cornering performance while maintaining high speed durability and ride comfort at the same level as the conventional tire 2.

It is a tire meridian half section view showing one embodiment of a pneumatic tire of the present invention. It is explanatory drawing of the belt layer of FIG. It is principal part sectional explanatory drawing of other embodiment of the pneumatic tire of this invention. FIG. 4 is an enlarged sectional view of a rubber-coated aliphatic polyketone fiber cord used for the third belt layer of FIG. 3.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Tread part 2 Side wall part 3 Bead part 4 Carcass layer 7 Belt layer 7A 1st belt layer 7B 2nd belt layer 7C 3rd belt layer I Vehicle mounting inner area O Vehicle mounting outer area R1, R2, R3 Rubber layer TC Tire Circumferential direction W2 Width of second belt layer W3 Width of third belt layer f Aliphatic polyketone fiber cord s Steel cord

Claims (9)

In a pneumatic tire in which a carcass layer is extended between the left and right bead portions, a plurality of belt layers are provided on the outer periphery side of the carcass layer of the tread portion, and the mounting direction with respect to the vehicle is specified.
A plurality of belt layers disposed adjacent to the carcass layer and having a steel cord embedded in a rubber layer inclined in one direction with respect to a tire circumferential direction; and an outer periphery of the first belt layer A second belt layer embedded in a rubber layer with an aliphatic polyketone fiber cord that is disposed on the side and inclined in the other direction with respect to the tire circumferential direction, and is disposed on the vehicle mounting outer region side on the outer peripheral side of the second belt layer A pneumatic tire having a third belt layer in which an aliphatic polyketone fiber cord inclined and arranged in the other direction with respect to the tire circumferential direction is embedded in a rubber layer. 2. The pneumatic tire according to claim 1, wherein aliphatic polyketone fiber cords of the third belt layer are arranged at substantially equal intervals, and the third belt layer is disposed in a vehicle mounting outer region. The pneumatic tire according to claim 2, wherein the width of the third belt layer is 1/3 to 1/2 of the width of the second belt layer. The aliphatic polyketone fiber cord of the third belt layer is spirally wound so as to be inclined in the other direction with respect to the tire circumferential direction, and the aliphatic polyketone fiber cord located on the vehicle mounting inner side is connected to the vehicle mounting outer side The pneumatic tire according to claim 1, wherein the pneumatic tire is wound with a smaller winding interval than the aliphatic polyketone fiber cord located at the position. 5. The pneumatic tire according to claim 4, wherein the aliphatic polyketone fiber cord of the third belt layer is wound with a wrapping interval gradually toward the vehicle wearing inner side. The pneumatic tire according to claim 4 or 5, wherein the third belt layer is formed by spirally winding one aliphatic polyketone fiber cord coated with rubber around the outer periphery of the second belt layer. The width of the third belt layer is 1/3 to 2/3 of the width of the second belt layer.
Or the pneumatic tire of 6. The pneumatic tire according to any one of claims 1 to 7, wherein an aliphatic polyketone fiber used for the aliphatic polyketone fiber cord of the second belt layer and the third belt layer has a strength of 9 cN / dtex or more. The pneumatic tire according to any one of claims 1 to 8, wherein a diameter of a wire constituting the steel cord of the first belt layer is 0.28 mm or less.

Images