JP2010013043A - Tire - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a tire capable of inhibiting separation of an end part of a turned-up section of a carcass layer. <P>SOLUTION: In a pneumatic tire 1 comprising a bead core 10a, a carcass layer 20, and an inner liner 30, the carcass layer 20 includes the turned-up section 21 where the end part 21a of the carcass layer 20 is turned up along the outer face of the bead core 10a, an annular reinforcing layer 40 constructed of cords 40a having the inclination of 10° or less with respect to a tangent (t) of the circumference centering on a rotary axis of the tire is arranged between the turned-up section 21 and the inner liner 30, and the oxygen permeability P of the inner liner 30, the thickness G of the inner liner 30 and the distance D between the inner liner 30 and the annular reinforcing layer 40 satisfies the relation 4×P/G<D. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to a tire, and more particularly, to a pneumatic tire including a pair of bead cores and a toroidal carcass layer provided between the pair of bead cores.

  Conventionally, a pneumatic tire is known that includes a bead portion including at least a pair of bead cores and a pair of bead fillers, and a toroidal carcass layer provided between the pair of bead cores. An inner liner is provided inside the tire of the carcass layer. The pair of bead portions are incorporated in a rim provided in the vehicle.

For example, the end portion of the carcass layer is wound up from the inner side in the tread width direction to the outer side in the tread width direction along the outer surface of the bead core (for example, Patent Document 1). That is, the carcass layer has a winding portion that is wound along the outer surface of the bead core.
JP 9-193624 A

  By the way, generally, at the time of internal pressure filling, a load in a direction in which the bead filler falls in the tread width direction outside is generated in the bead portion. Due to such a load, stress concentrates on a part of the end portion of the winding portion (end portion of the carcass layer). Therefore, separation at the end of the winding portion may occur.

  Therefore, the present invention has been made to solve the above-described problem, and an object of the present invention is to provide a tire that can suppress the occurrence of separation at the end of the rolled-up portion of the carcass layer.

  In order to solve the above-described problems, the present invention has the following features. First, the first feature is that a pair of bead cores (bead core 10a), a toroidal carcass layer (carcass layer 20) provided between the pair of bead cores, and an inner liner (inner Tire (pneumatic tire 1) provided with a liner 30), wherein the carcass layer has a winding portion (winding portion 21) in which an end portion (end portion 21a) of the carcass layer is wound along the outer surface of the bead core. An annular reinforcement constituted by a reinforcing element (cord 40a) having an inclination of 10 ° or less with respect to a tangent (t) of the circumference around the tire rotation axis between the winding portion and the inner liner Layer (annular reinforcing layer 40) is provided, the oxygen permeability P of the inner liner, the thickness G of the inner liner, and the inner liner and the annular auxiliary layer. The distance D between the layers is summarized in that it satisfies the relationship 4 × P / G <D.

  According to such a feature, an annular reinforcing layer constituted by a reinforcing element having an inclination of 10 ° or less with respect to a circumferential tangent centered on the tire rotation axis is provided between the winding portion and the inner liner. Thus, the rigidity of the carcass layer is improved by the reinforcing element in the circumferential direction around the tire rotation axis. That is, the stress on the end portion of the winding portion is dispersed by the reinforcing element, and the concentration of stress on a part of the end portion of the winding portion is suppressed. Therefore, it is possible to suppress the occurrence of separation at the end of the rolled-up portion of the carcass layer.

  Furthermore, the oxygen transmission rate P of the inner liner, the thickness G of the inner liner, and the distance D between the inner liner and the annular reinforcing layer satisfy the relationship of 4 × P / G <D. When the transmission amount (P / G) is large, the distance D is set long. Therefore, it is possible to reduce the amount of oxygen that reaches the reinforcing elements constituting the annular reinforcing layer, and it is possible to suppress deterioration of the carcass layer and the annular reinforcing layer.

  Other features further include a rubber layer (rubber layer 70) provided between the wound-up portion and the annular reinforcing layer, and the thickness (L) of the rubber layer is in the range of 0.3 to 2.0 mm. This is the gist.

  Another feature is that the inner liner is a modified ethylene-vinyl alcohol in which 1 to 50 parts by mass of an epoxy compound is reacted with 100 parts by mass of an ethylene-vinyl alcohol copolymer having an ethylene content of 20 to 50% mol. The gist is to include a copolymer.

  Another feature is summarized in that the inner liner has an ethylene layer formed of a modified ethylene-vinyl alcohol copolymer and a urethane layer formed of a thermoplastic urethane-based elastomer.

  ADVANTAGE OF THE INVENTION According to this invention, the tire which makes it possible to suppress generation | occurrence | production of the separation of the edge part of the winding part of a carcass layer can be provided.

[First Embodiment]
Next, an example of a pneumatic tire according to the first embodiment will be described with reference to the drawings. In the following description of the drawings, the same or similar parts are denoted by the same or similar reference numerals.

  However, it should be noted that the drawings are schematic and ratios of dimensions are different from actual ones. Accordingly, specific dimensions and the like should be determined in consideration of the following description. Moreover, it is a matter of course that portions having different dimensional relationships and ratios are included between the drawings.

(Composition of pneumatic tire)
First, the configuration of the pneumatic tire according to the first embodiment will be described with reference to FIG. FIG. 1 is a cross-sectional view in the tread width direction showing the pneumatic tire according to the first embodiment. The pneumatic tire according to the first embodiment is a truck / bus tire.

  As shown in FIG. 1, the pneumatic tire 1 is provided in a toroidal shape between a bead portion 10 including at least a pair of bead cores 10a and a pair of bead fillers 10b, and a pair of bead cores 10a, and along the outer periphery of the bead core 10a. And a carcass layer 20 wound up from the inner side in the tread width direction to the outer side in the tread width direction.

  The carcass layer 20 has a winding portion 21 in which an end portion of the carcass layer 20 is wound along the outer periphery of the bead core 10a. An end 21 a of the winding portion 21 extends in the vicinity of the flange portion F of the rim wheel R.

  Inside the carcass layer 20 is provided an inner liner 30 which is a highly airtight rubber layer corresponding to a tube. An annular reinforcing layer 40 that reinforces the winding portion 21 is provided between the inner liner 30 and the winding portion 21 (the carcass layer 20 located in the bead portion 10).

  Of course, the annular reinforcing layer 40 may be provided between the inner liner 30 and the winding portion 21 and may extend to just below the bead core 10a.

  A tread portion 50 that is in contact with the road surface is provided outside the carcass layer 20 in the tire radial direction. In addition, a plurality of belt layers 60 that reinforce the tread portion 50 are provided between the carcass layer 20 and the tread portion 50.

(Configuration near the bead)
Next, the inner liner 30 and the annular reinforcing layer 40 positioned in the bead portion 10 described above will be described with reference to FIGS. 2 and 3. FIG. 2 is a cross-sectional view in the tread width direction showing the vicinity of a bead portion constituting the pneumatic tire according to the first embodiment, and FIG. 3 is a carcass constituting the pneumatic tire according to the first embodiment. It is a side view (A arrow line view of FIG. 2) which shows a layer and a cyclic | annular reinforcement layer.

  As shown in FIG.2 and FIG.3, the inner liner 30 makes 1-50 mass parts of epoxy compounds react with 100 mass parts of ethylene-vinyl alcohol copolymers which have an ethylene content of 20-50% mol. Modified ethylene-vinyl alcohol copolymer.

  Specifically, the inner liner 30 includes an ethylene layer 31 formed of a modified ethylene-vinyl alcohol copolymer, and a urethane layer provided on the inner side in the tire radial direction of the ethylene layer 31 and formed of a thermoplastic urethane-based elastomer. 32.

  As shown in FIG. 3, the annular reinforcing layer 40 is formed by a cord 40a (reinforcing element) and a rubber 40b having an inclination of 10 ° or less with respect to a circumferential tangent t centering on a tire rotation axis (not shown). It is configured. The cord 40a is preferably a steel wire or an aramid fiber.

  Here, as shown in FIG. 2, the oxygen permeability P of the inner liner 30, the thickness G of the inner liner 30, and the distance D between the inner liner 30 and the annular reinforcing layer 40 are 4 × P / G < The relationship of D is satisfied.

The oxygen permeability P represents the oxygen permeability ((cm ³ · cm / cm ² · sec · cmHg) × 10 ⁻¹⁰ )) of the inner liner 30 under the condition of 20 ° C. × 65% RH atmosphere. The measurement of the oxygen transmission rate will be briefly described.

  The rectangular sample of the inner liner 30 in the bead part 10 was conditioned for 5 days under the condition of 20 degrees and 65% RH atmosphere. Using two conditioned samples, the oxygen transmission rate was measured using MOCONOX-TRAN 2/20 model manufactured by Modern Control. Specifically, the average value of oxygen permeability was calculated in accordance with JIS K7126 (isobaric method) under the conditions of 20 degrees and 65% RH atmosphere.

  The thickness G of the inner liner 30 indicates the gauge thickness (mm) of the inner liner at the time of product. Further, as shown in FIG. 2, the distance D indicates a distance (mm) from the interface on the carcass layer 20 side in the inner liner 30 to the interface on the carcass layer side in the annular reinforcing layer 40. That is, the distance D is a distance (mm) from the interface on the carcass layer 20 side in the ethylene layer 31 to the interface on the carcass layer side in the annular reinforcing layer 40.

(Action / Effect)
According to the pneumatic tire 1 which concerns on 1st Embodiment demonstrated above, between the winding part 21 and the inner liner 30, it is within 10 degrees with respect to the tangent t of the circumference centering on a tire rotating shaft. By providing the annular reinforcing layer 40 composed of the inclined cord 40a (reinforcing element) and the rubber 40b, the rigidity of the carcass layer 20 is determined by the cord 40a in the circumferential direction around the tire rotation axis. improves. That is, the stress on the end portion 21a of the winding portion 21 is dispersed by the cord 40a, and the concentration of stress on a part of the end portion 21a of the winding portion 21 is suppressed. Therefore, it is possible to suppress the occurrence of separation at the end portion 21a of the winding portion 21 of the carcass layer 20.

  Further, the oxygen permeability P of the inner liner 30, the thickness G of the inner liner 30, and the distance D between the inner liner 30 and the annular reinforcing layer 40 satisfy the relationship of 4 × P / G <D, When the oxygen transmission amount (P / G) of the inner liner 30 is large, the distance D is set to be long. Therefore, the amount of oxygen reaching the cord 40a constituting the annular reinforcing layer 40 can be reduced, and deterioration of the carcass layer 20 and the annular reinforcing layer 40 can be suppressed.

[Second Embodiment]
Next, the configuration of the pneumatic tire according to the second embodiment will be described with reference to FIG. FIG. 4 is a cross-sectional view in the tread width direction showing the vicinity of a bead portion constituting the pneumatic tire according to the second embodiment. In addition, the same part (same structure) as the pneumatic tire 1 which concerns on 1st Embodiment mentioned above is attached | subjected with the same code | symbol, and a different part is mainly demonstrated.

  As shown in FIG. 4, the pneumatic tire 1 further includes a rubber layer 70 provided between the wound-up portion 21 and the annular reinforcing layer 40. The rubber layer 70 has a thickness L in the range of 0.3 to 2.0 mm.

  According to the pneumatic tire 1 according to the second embodiment as described above, the thickness of the rubber layer 70, that is, the distance between the rolled-up portion 21 and the annular reinforcing layer 40 is in the range of 0.3 to 2.0 mm. As a result, the distortion generated in the rubber layer 70 can be suppressed, and the reinforcing effect of the winding portion 21 can be sufficiently obtained.

[Other embodiments]
As described above, the contents of the present invention have been disclosed through the embodiments of the present invention. However, it should not be understood that the descriptions and drawings constituting a part of this disclosure limit the present invention.

  Specifically, the carcass layer 20 has been described as being wound up from the inner side in the tread width direction to the outer side in the tread width direction along the outer periphery of the bead core 10a, but is not limited thereto, and is not limited to this. It may be wound up outward in the width direction.

  Moreover, although the edge part 21a of the winding part 21 demonstrated as what was extended in the flange part F vicinity of the rim wheel R, it is not limited to this, For example, as shown in FIG. Although it may be wound over the entire outer periphery and is not shown, it may extend to the vicinity of the position of the maximum tire width.

  Moreover, although the inner liner 30 was demonstrated as what was comprised by the ethylene layer 31 and the urethane layer 32, it is not limited to this, You may be comprised only by the ethylene layer 31 and other than ethylene Of course, it may be made of a material.

  Moreover, although the urethane layer 32 which comprises the inner liner 30 demonstrated as what was provided in the tire radial direction inner side of the ethylene layer 31, it is not limited to this, The tire radial direction outer side of the ethylene layer 31, That is, the ethylene layer 31 may be provided on the carcass layer 20 side.

  Further, the annular reinforcing layer 40 has been described as being constituted by the cord 40a (reinforcing element) and the rubber 40b. However, the annular reinforcing layer 40 is not limited thereto, and is constituted only by the cord 40a (reinforcing element). Of course.

  Further, the pneumatic tire 1 has been described as a truck / bus tire, but the pneumatic tire 1 is not limited thereto, and may be a heavy-duty tire such as a passenger tire or a construction tire. The pneumatic tire 1 includes a tube tire and a teamless tire, and may be a tire other than the pneumatic tire (for example, a solid rubber tire).

  From this disclosure, various alternative embodiments, examples and operational techniques will be apparent to those skilled in the art. Therefore, the technical scope of the present invention is defined only by the invention specifying matters according to the scope of claims reasonable from the above description.

  Next, in order to further clarify the effects of the present invention, the results of tests performed using pneumatic tires (truck / bus radial tires) according to the following comparative examples and examples will be described. In addition, this invention is not limited at all by these examples.

  Data on each pneumatic tire was measured under the following conditions.

・ Tire size: 275 / 80R22.5
・ Wheel size: 8.25 × 22.5
・ Internal pressure condition: 900kPa
・ Load condition: 3000kg
Comparative Examples 1 to 3 in which the oxygen permeability P of the inner liner 30, the thickness G of the inner liner 30, and the relationship of the distance D between the inner liner 30 and the annular reinforcing layer 40 (P / G, D relationship) were changed. The structure of the pneumatic tire according to 3 and Examples 1 to 5 and the weight oxygen concentration in the rubber will be described with reference to Table 1 and FIG. In addition, each pneumatic tire is shown in FIGS. 1-3, and structures other than the relationship of said P, P / G, and D are the same.

<Weight oxygen concentration in rubber>
Each pneumatic tire mounted on the test rim was rotated at a speed of 60 km / h for 100,000 km, and the weight oxygen concentration in rubber between the carcass layer 20 and the annular reinforcing layer 40 of each pneumatic tire was measured. In addition, the weight oxygen concentration in rubber | gum is so low that a numerical value is small.

  As a result, as shown in Table 1 and FIG. 6, the pneumatic tire according to Examples 1 to 5 is between the carcass layer 20 and the annular reinforcing layer 40 as compared with the pneumatic tire according to Comparative Examples 1 to 3. It was found that air hardly penetrates the inner liner 30 because the weight oxygen concentration in the rubber is low.

It is a tread width direction sectional view showing the pneumatic tire concerning a 1st embodiment. It is a tread width direction sectional view showing the bead part neighborhood which constitutes the pneumatic tire concerning a 1st embodiment. It is a side view (A arrow line view of FIG. 2) which shows the carcass layer and annular reinforcement layer which comprise the pneumatic tire which concerns on 1st Embodiment. It is a tread width direction sectional view showing the neighborhood of a bead part which constitutes a pneumatic tire concerning a 2nd embodiment. It is a tread width direction sectional view showing the neighborhood of a bead part which constitutes a pneumatic tire concerning other embodiments. It is a graph which shows the weight oxygen concentration in rubber | gum in the pneumatic tire which concerns on a comparative example and an Example.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 ... Pneumatic tire, 10 ... Bead part, 10a ... Bead core, 10b ... Bead filler, 20 ... Carcass layer, 21 ... Winding up part, 21a ... End part, 30 ... Inner liner, 31 ... Ethylene layer, 32 ... Urethane layer, 40 ... annular reinforcing layer, 40a ... cord (reinforcing element), 40b ... rubber, 50 ... tread part, 60 ... belt layer, 70 ... rubber layer

Claims (4)

A tire comprising a pair of bead cores, a toroidal carcass layer provided between the pair of bead cores, and an inner liner provided inside the tire of the carcass layer,
The carcass layer has a winding part in which an end of the carcass layer is wound along the outer surface of the bead core,
Between the winding portion and the inner liner, an annular reinforcing layer constituted by a reinforcing element having an inclination of 10 ° or less with respect to a tangent of the circumference around the tire rotation axis is provided,
The oxygen permeability P of the inner liner, the thickness G of the inner liner, and the distance D between the inner liner and the annular reinforcing layer satisfy a relationship of 4 × P / G <D. tire. A rubber layer provided between the rolled-up portion and the annular reinforcing layer;
The tire according to claim 1, wherein the rubber layer has a thickness in a range of 0.3 to 2.0 mm.   The inner liner is a modified ethylene-vinyl alcohol copolymer obtained by reacting 1 to 50 parts by mass of an epoxy compound with respect to 100 parts by mass of an ethylene-vinyl alcohol copolymer having an ethylene content of 20 to 50% mol. The tire according to claim 1, comprising: The inner liner is
An ethylene layer formed by the modified ethylene-vinyl alcohol copolymer;
The tire according to claim 3, further comprising a urethane layer formed of a thermoplastic urethane-based elastomer.

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