JP2006188176A - Pneumatic tire - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a pneumatic tire capable of securing sufficient shock burst resistance and run-flat durability without drastically increasing the weight of the tire. <P>SOLUTION: At least one of a carcass layer 6 is extended between right and left bead parts 3, and both end parts 6A thereof are folded around a bead core 4 buried in the bead part 3 from the inside of the tire to the outside. A belt layer 7 is arranged on an outer peripheral side of the carcass layer 6 of a tread part 1, and a reinforcing rubber layer 11 extending to the tire radial direction and having a crescent-shaped cross section is arranged on the inner side of the carcass layer 6 of the right and left side wall parts 2, respectively. A fiber reinforcing layer 12 is provided on an inner peripheral side of the belt layer 7 of the tread part 1. The fiber reinforcing layer 12 is extended only to the right and left side wall parts 2 so as to be overlapped with the reinforcing rubber layer 11 in the tire side surface view. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a pneumatic tire, and more particularly, to a pneumatic tire that ensures good shock burst resistance and run flat durability without significantly increasing the tire weight.

  Conventionally, a pneumatic tire in which a reinforcing rubber layer having a crescent-shaped cross section extending in the tire radial direction is disposed inside the carcass layer of the sidewall portion, and a punctured tire is supported by the reinforcing rubber layer to enable run-flat running. Has been proposed (see, for example, Patent Documents 1 and 2).

  In the pneumatic tire described above, the support capability of the punctured tire is improved as the thickness of the reinforcing rubber layer is increased, and the distance during the run-flat running can be increased. Therefore, if an attempt is made to secure a certain amount of allowable thickness and to achieve high run-flat durability, the tire weight will increase significantly, which will result in tire performance such as rolling resistance and riding comfort during normal driving. descend.

As a countermeasure, when trying to reduce the tire weight by reducing the number of carcass layers arranged in multiple layers in a tire with a low flatness ratio, the tire bursts against an impact when it contacts a road surface projection such as a cat's eye. The shock burst resistance is greatly reduced. Furthermore, a buckling phenomenon occurs in which the center portion of the tread surface is lifted from the road surface during run flat traveling, thereby reducing the ground contact area and lowering the run flat durability.
Japanese Patent Laid-Open No. 5-112110 JP 2000-168319 A

  An object of the present invention is to provide a pneumatic tire capable of ensuring good shock burst resistance and run-flat durability without significantly increasing the tire weight.

  The present invention that achieves the above object embeds bead cores having bead fillers arranged on the outer peripheral side in the left and right bead parts, respectively, and extends at least one carcass layer between the left and right bead parts. Both ends are folded around the bead core from the inside of the tire to the outside, a belt layer is arranged on the outer periphery side of the carcass layer of the tread, and the crescent cross section extends in the tire radial direction inside the carcass layer of the left and right side walls. In the pneumatic tire in which the reinforcing rubber layers are respectively disposed, the left and right sides are provided so that a fiber reinforcing layer is provided on the inner peripheral side of the belt layer of the tread portion, and the fiber reinforcing layer overlaps with the reinforcing rubber layer in a side view of the tire. It is characterized by extending only to the wall portion.

  According to the present invention described above, since the fiber reinforcement layers extending to the left and right sidewall portions are arranged so as to overlap with the reinforcement rubber layer, even if the number of carcass layers conventionally disposed is reduced, A decrease in shock burst resistance and buckling resistance can be avoided, and good shock burst resistance and run-flat durability can be ensured. In addition, since the fiber reinforcing layer extends only to the sidewall portion, an increase in tire weight can be suppressed and a significant increase can be avoided.

  Hereinafter, embodiments of the present invention will be described in detail with reference to the accompanying drawings.

  FIG. 1 shows an embodiment of a pneumatic tire according to the present invention, where 1 is a tread portion, 2 is a sidewall portion, 3 is a bead portion, and CL is a tire equatorial plane.

  A bead core 4 is embedded in each of the left and right bead portions 3. A bead filler 5 having a triangular cross section extending to the sidewall portion 2 is disposed on the outer peripheral side of the bead core 4.

  A single carcass layer 6 in which organic fiber cords extending in the tire radial direction are arranged at predetermined intervals in the tire circumferential direction and covered with rubber is extended between the left and right bead portions 3. Both end portions 6 </ b> A of the carcass layer 6 are folded back around the bead core 4 from the tire inner side to the outer side so as to sandwich the bead filler 5, and further extend to the radially outer side of the sidewall portion 2.

  On the outer peripheral side of the carcass layer 6 of the tread portion 1, a plurality of belt layers 7 are disposed that are rubber-coated with reinforcing cords inclined with respect to the tire circumferential direction. On the outer peripheral side of the belt layer 7, a plurality of belt cover layers 8 are provided in which an organic fiber cord is spirally wound in the tire circumferential direction and covered with rubber. On the outer peripheral side of both end portions of the belt cover layer 8, an edge cover layer 9 in which an organic fiber cord is spirally wound in the tire circumferential direction and covered with rubber is disposed.

  An inner liner layer 10 extending between the left and right bead portions 3 is provided inside the carcass layer 6. Reinforcing rubber layers 11 made of crescent-shaped rubber for supporting the tire during run-flat running are provided inside the carcass layers 6 of the left and right sidewall portions 2. The reinforcing rubber layer 11 is disposed between the carcass layer 6 and the inner liner layer 10, and the belt layer 7 is formed on the outer side in the tire radial direction from a position overlapping the bead filler 5 extending to the sidewall portion 2 in a side view of the tire. It extends to the inner diameter side of the end.

  On the inner peripheral side of the belt layer 7 of the tread portion 1, a single layer of fiber reinforcement layer in which organic fiber cords extending in the tire radial direction (tire width direction) are arranged at predetermined intervals in the tire circumferential direction and covered with rubber 12 is provided. The fiber reinforcing layer 12 is disposed between the carcass layer 6 and the belt layer 7 and extends to the left and right sidewall portions 2 so as to overlap the reinforcing rubber layer 11 in a side view of the tire while adjoining the carcass layer 6. ing.

  The fiber reinforcing layer 12 does not extend to the bead part 3 but extends only to the side wall part 2, and the bead filler extends to the side wall part 2 so as to overlap with the reinforcing rubber layer 11 in a side view of the tire. The end portion 12 </ b> A of the fiber reinforcing layer 12 is located in the overlapping region S with 5.

  In the figure, reference numeral 13 denotes a chafer layer disposed in the bead portion 3.

  In the present invention described above, even if the number of carcass layers conventionally disposed is reduced by the fiber reinforcing layer 12 extended to the left and right sidewall portions 2 so as to overlap the reinforcing rubber layer 11, shock resistance It becomes possible to maintain the burst property and the run flat durability at the same level as before. And since the fiber reinforcement layer 12 is extended only to the sidewall part 2, it can suppress that a tire weight increases.

  In the present invention, the organic fiber cord used for the fiber reinforcing layer 12 can be the same as that used for the carcass layer 6, and for example, a polyester cord or a rayon cord can be preferably exemplified.

  The arrangement angle of the organic fiber cords of the fiber reinforcement layer 12 with respect to the tire radial direction is preferably in a range of ± 10 ° with respect to the tire radial direction. Normally, in a pneumatic tire that enables run flat running, the organic fiber cords of the carcass layer 6 are arranged in a range of ± 10 ° with respect to the tire radial direction from the viewpoint of run flat durability. The organic fiber cord is preferably the same as the organic fiber cord of the carcass layer 6 in terms of run-flat durability. The arrangement density of the organic fiber cords of the fiber reinforcing layer 12 can be the same as that of the carcass layer 6.

  In the above embodiment, an example in which one carcass layer 6 is provided has been described, but two carcass layers 6 may be provided. Conventionally, even in a pneumatic tire capable of run-flat running provided with three carcass layers, the same effect as described above can be obtained by disposing the fiber reinforcing layer 12 instead of one carcass layer. The invention may be any pneumatic tire that has at least one carcass layer 6 and can be run flat by the reinforcing rubber layer 11.

  The present invention can be preferably used for a pneumatic tire having a low flatness ratio (flatness ratio of 55% or less) particularly used for a passenger car, but is not limited thereto.

  The tire of the present invention having the configuration shown in FIG. 1 in which the tire size is common to 245 / 40R18 and one fiber reinforcing layer is disposed outside one carcass layer, and a comparative tire having no fiber reinforcing layer in the present tire, Conventional tires each having the structure shown in FIG. 2 in which two carcass layers are arranged were produced.

  In the tire of the present invention, a rayon cord (1840 dtex / 2) is used as the reinforcing cord of the fiber reinforcing layer, the arrangement density is 47 pieces / 50 mm, and the arrangement angle is 10 °.

When each of these test tires was subjected to an evaluation test of tire mass, shock burst resistance, and run-flat durability by the following evaluation method, the results shown in Table 1 were obtained.
Tire Mass The mass of each test tire was measured, and the result was shown as an index value with the conventional tire as 100. The smaller this value, the smaller the tire mass.
Mounting the anti-shock bursts from each test tire on a rim having a rim size of 18 × 8 J, and the air pressure in 230KP a attached to the front left side of the rear-wheel drive vehicle of the exhaust amount 4300Cc, enters at an angle 30 ° to the curb height 110mm The test of overcoming the curb was repeated while gradually increasing the speed of overcoming, and the speed when air leakage or burst occurred in the test tire was measured. The larger this value, the better the shock burst resistance.
Run-flat durability Each test tire is mounted on a rim with a rim size of 18 x 8 J, mounted on the right side of the front wheel of a 4300cc rear-wheel drive vehicle with an air pressure of 0 kPa, and an elliptical round test course at 80 km / h. The vehicle traveled counterclockwise, and the distance traveled when the test driver felt abnormal vibration due to tire failure was measured. The result was expressed as an index value with the conventional tire as 100. The larger this value, the better the run flat durability. Other than the front right wheel of the front wheel drive vehicle, tires and rims of the same size as above were used, and the air pressure was set to 230 kPa.

  From Table 1, the tire of the present invention can effectively reduce the tire mass compared to the conventional tire, and the shock burst resistance and run-flat durability are at the same level, and it is good without significantly increasing the tire weight. It can be seen that high shock burst resistance and run flat durability can be secured.

It is a tire meridian half section view showing one embodiment of a pneumatic tire of the present invention. It is a tire meridian half section view of the conventional pneumatic tire.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Tread part 2 Side wall part 3 Bead part 4 Bead core 5 Bead filler 6 Carcass layer 6A End part 7 Belt layer 11 Reinforcement rubber layer 12 Fiber reinforcement layer 12A End part S Overlapping area

Claims (4)

A bead core having bead fillers arranged on the outer peripheral side is embedded in the left and right bead parts, and at least one carcass layer is extended between the left and right bead parts, and both ends of the carcass layer are inside the tire around the bead core. Folded from the outside to the outside, the belt layer is arranged on the outer periphery of the carcass layer of the tread part, and the crescent-shaped reinforcing rubber layer extending in the tire radial direction is arranged inside the carcass layer of the left and right sidewall parts, respectively. In the tire,
The pneumatic tire which provided the fiber reinforcement layer in the belt layer inner peripheral side of the said tread part, and extended this fiber reinforcement layer only to the left and right side wall part so that it might overlap with the said reinforcement rubber layer by tire side view.   The bead filler extends to a sidewall portion so as to overlap with the reinforcing rubber layer in a tire side view, and an end portion of the fiber reinforcing layer is located in an overlapping region of the bead filler and the reinforcing rubber layer. The described pneumatic tire.   The pneumatic tire according to claim 1 or 2, wherein the fiber reinforcing layer is disposed between the belt layer and the carcass layer.   The pneumatic tire according to claim 1, 2, or 3, wherein organic fiber cords in which the fiber reinforcing layer extends in the tire radial direction are arranged at predetermined intervals in the tire circumferential direction.

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