JP2006123707A - Run-flat tire - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a run-flat tire capable of securing durability against run-flat travelling even when it is installed on a vehicle whose tire position is high and whose body weight is heavy such as an SUV type automobile, etc. while restraining deterioration of ride comfort in normal travelling and in the runflat travelling. <P>SOLUTION: This run-flat tire 10 is furnished with a side reinforcing rubber layer 17 arranged on the inside in the tire diametrical direction from a carcass layer 12 and a cross-section shape in the tread widthwise direction of which is crescent on a side wall part 15sw and is furnished with an outside triaxial fabric layer 18out triaxial fabric weaving cords arranged along three axial directions crossing with each other with each other of which is covered with a rubber material on the outside in the tread widthwise direction of the side reinforcing rubber layer 17. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a run-flat tire provided with a side reinforcing rubber layer that is disposed on the inner side in the tread width direction than the carcass layer supported by the pair of bead portions in the sidewall portion and has a crescent-shaped cross-sectional shape in the tread width direction. .

  Conventionally, as a type of run flat tire that can travel a certain distance even when the internal pressure is reduced due to puncture or the like, a run flat that includes a side reinforcing rubber layer in the side wall portion having a crescent-shaped cross section in the tread width direction Tires are known.

  Such side-reinforced run-flat tires are mainly mounted on passenger cars in which ride comfort is important and the vehicle weight is relatively light.

  Further, in such a side-reinforced type run-flat tire, a “reinforced canvas” in which a canvas composed of organic fibers (for example, aromatic polyamide fibers) is covered with rubber inside the side reinforcing rubber layer and integrated. A technique further including a “layer” is disclosed (for example, Patent Document 1).

In a side reinforcing type run flat tire having such a reinforcing canvas layer, the side reinforcing rubber layer is reinforced by the reinforcing canvas layer. Can be improved.
Japanese Patent Laid-Open No. 11-278019 (page 3, FIG. 1)

  However, the conventional run flat tire described above has the following problems. A pneumatic tire mounted on an SUV vehicle such as a minivan has a high designated tire height that is a length from a bead portion to a tread portion. In addition, SUV automobiles generally have a heavier vehicle weight than passenger cars.

  That is, in a run flat tire mounted on such an SUV automobile, the side reinforcing rubber layer is used in order to prevent the side wall portion from being greatly bent during run flat running where the internal pressure is reduced, that is, to prevent shear deformation. It was necessary to increase the thickness in the tread width direction.

  When the side reinforcing rubber layer is thickened, the run-flat tire longitudinal spring characteristics are increased and the run-flat tire is hardened in the longitudinal direction. Further, when the side reinforcing rubber layer is thickened, the weight of the run-flat tire, that is, the unsprung weight of the SUV automobile is increased.

  For this reason, in the SUV type automobile equipped with such a run-flat tire, the ride comfort is remarkably deteriorated.

  Therefore, the present invention has been made in view of such a situation, and the designated tire height is high and the vehicle weight, such as an SUV-based automobile, is suppressed while suppressing deterioration of the riding comfort during normal and run-flat driving. An object of the present invention is to provide a run-flat tire capable of ensuring durability against run-flat running even when it is mounted on a heavy vehicle.

  In order to solve the above-described problems, the present invention has the following features. First, the first feature of the present invention is that the sidewall portion (sidewall portion 15sw) is disposed on the inner side in the tread width direction than the carcass layer (carcass layer 12) supported by the pair of bead portions (bead portion 11). A run flat tire (for example, run flat tire 10) having a side reinforcing rubber layer (side reinforcing rubber layer 17) having a crescent-shaped cross-sectional shape in the tread width direction, wherein the side reinforcing rubber layer has a tread width direction. On the outside, a triaxial fabric layer (triaxial fabric 18) in which cords (cords 18X, 18Y, 18Z) arranged along three axial directions intersecting each other are woven together and covered with a rubber material ( The gist is to include an outer triaxial fabric layer 18out).

  According to this feature, since the triaxial fabric layer is provided, shear deformation of the side reinforcing rubber layer is suppressed. Specifically, the portion of the side reinforcing rubber layer on the “outer side” in the tread width direction is suppressed from being pulled and deformed.

  That is, the rubber constituting the side reinforcing rubber layer is prevented from being broken, and durability against run-flat running is improved. In particular, according to this feature, when a run-flat tire is mounted on a vehicle having a high designated tire height and a heavy vehicle weight, such as an SUV-based automobile, durability against run-flat traveling can be ensured.

  Further, according to the triaxial woven fabric, a reinforcing layer having a high shear rigidity and a rigidity distribution close to isotropic can be realized by only one layer, and therefore, without increasing the weight of the run flat tire, Flat performance can be improved. For this reason, the deterioration of the riding comfort at the normal time and during the run-flat running is suppressed.

  A second feature of the present invention relates to the first feature of the present invention, and is summarized in that the triaxial fabric layer is disposed on the outer side in the tread width direction and on the inner side in the tread width direction of the side reinforcing rubber layer. .

  A third feature of the present invention relates to the first or second feature of the present invention, in which the triaxial fabric layer has an upper end (upper end 17 ue) and a lower end (upper end) of the side reinforcing rubber layer in a cross section in the tread width direction. The gist is that it is 5 mm or longer from the lower end 17le).

  A fourth feature of the present invention relates to the first to third features of the present invention, wherein the thickness (thickness T) of the thickest portion of the side reinforcing rubber layer is 15 mm or less in the cross section in the tread width direction. It is a summary.

  The fifth feature of the present invention relates to the first to fourth features of the present invention, and is summarized in that the carcass layer is composed of two or less carcasses.

  A sixth feature of the present invention relates to the first to fifth features of the present invention, wherein an end portion (for example, an end portion 28 oe) of the triaxial fabric layer located on the bead portion side is the bead portion. The gist is that it is folded and located outside the carcass layer in the tread width direction.

  According to the features of the present invention, run-flat running is possible even when the vehicle is mounted on a vehicle having a high designated tire height and heavy vehicle weight, such as an SUV automobile, while suppressing deterioration in ride comfort during normal and run-flat running. The run flat tire which can ensure the durability with respect to can be provided.

  Next, an embodiment of a run flat tire according to the present invention 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 and the like 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.

[First Embodiment]
(Configuration of run-flat tire)
(1) Overall Configuration of Run Flat Tire FIG. 1 is a partial cross-sectional view in the tread width direction of a run flat tire 10 according to the first embodiment of the present invention. Since the run flat tire 10 has a symmetrical shape with the tire equator line CL as the center, only one side of the run flat tire 10 with the tire equator line CL as the center is shown.

  As shown in the figure, the run-flat tire 10 is disposed in the tread width direction inner side than the carcass layer 12 supported by the pair of bead portions 11 in the sidewall portion 15sw, and the cross-sectional shape in the tread width direction is a crescent shape. It is a side reinforcement type run flat tire provided with the side reinforcement rubber layer 17 which is.

  The bead part 11 is comprised by the bead core 11a and the bead filler 11b. The bead portion 11 supports both ends of the carcass layer 12 and fixes the run-flat tire 10 to a rim wheel (not shown).

  The carcass layer 12 forms a skeleton of the run-flat tire 10 and is constituted by two layers of carcass in the present embodiment. The carcass layer 12 is formed by covering a carcass cord (not shown) disposed along the substantially radial direction of the run-flat tire 10 with a rubber material.

  The belt layers 13a and 13b tighten and reinforce the carcass layer 12. The belt layers 13a and 13b are made by covering a steel cord or an organic fiber cord (not shown) disposed with a predetermined angle (for example, ± 25 degrees) with respect to the tire equator line CL with a rubber material. is there.

  The cap layer 14 has a width equal to or larger than the entire width of the belt layers 13a and 13b, and reinforces the belt layers 13a and 13b.

  A tread portion 15tr that contacts the road surface is provided on the outer side in the tire radial direction of the cap layer 14.

  The inner liner 16 is provided on the inner surface of the run flat tire 10 and prevents sudden leakage of compressed air filled in the run flat tire 10 (specifically, the run flat tire 10 assembled to the rim wheel). Is.

  The side reinforcing rubber layer 17 is a reinforcing member for withstanding a load such as a vehicle weight during traveling (run-flat traveling) in a state where the internal pressure of the run-flat tire 10 is reduced by puncture or the like.

  The side reinforcing rubber layer 17 is disposed on the inner side in the tread width direction than the carcass layer 12, and the cross-sectional shape in the tread width direction is a crescent shape. In the cross section in the tread width direction, the thickness T of the thickest portion of the side reinforcing rubber layer 17 is 15 mm or less.

  The outer triaxial fabric layer 18out is formed by weaving cords 18X, 18Y, and 18Z (see FIG. 2) that are arranged along three axial directions intersecting each other on the outer side in the tread width direction of the side reinforcing rubber layer 17. A shaft fabric 18 (see FIG. 2) is covered with a rubber material.

The outer triaxial fabric layer 18out is set longer than the upper end 17ue and the lower end 17le of the side reinforcing rubber layer 17 by 5 mm or more in the cross section in the tread width direction. In other words, the difference between _{D 1} and the difference _{D 2} in the figure is set to at least 5 mm.

(2) Configuration of Triaxial Fabric Next, the configuration of the triaxial fabric 18 constituting the outer triaxial fabric layer 18out will be described with reference to FIG. As described above, the outer triaxial fabric layer 18out is composed of the triaxial fabric 18 obtained by interweaving the cords 18X, 18Y, and 18Z (see FIG. 2) arranged along the three axial directions intersecting each other with a rubber material. It is coated.

  FIG. 2 shows the configuration of the triaxial fabric 18 itself, in which the rubber material used for coating is removed from the outer triaxial fabric layer 18out.

  As shown in the figure, the triaxial fabric 18 is arranged in the same plane along the cord 18X arranged along the X axis, the cord 18Y arranged along the Y axis, and the Z axis. The cord 18Z is interwoven with each other. Each cord (codes 18X, 18Y, 18Z) crosses one after the other in the vertical direction at the intersection.

  The intersection angle between the cord 18X and the cord 18Y and the intersection angle between the cord 18X and the cord 18Z are set to about 60 degrees, respectively. Further, the cord 18 </ b> X is disposed along the substantially radial direction of the run flat tire 10.

  In this embodiment, each cord (code 18X, 18Y, 18Z) is constituted by aromatic polyamide fiber.

  Any material may be used for each cord (code 18X, 18Y, 18Z), but in terms of weight and strength, organic fiber (for example, aromatic polyamide fiber, fatty acid polyamide fiber, polyester fiber, poly It is preferable to use paraphenylenebenzeneoxazole fiber, polyvinyl alcohol-based synthetic fiber or carbon fiber), inorganic fiber (for example, glass fiber), or metal fiber (for example, steel wire). May be used.

[Second Embodiment]
Next, a second embodiment of the present invention will be described with reference to FIG. Hereinafter, the part different from the run flat tire 10 according to the first embodiment of the present invention will be mainly described, and the description of the same part as the run flat tire 10 will be omitted as appropriate.

  As shown in FIG. 3, in the run flat tire 10 ′ according to the present embodiment, the triaxial fabric layer obtained by coating the triaxial fabric 18 with a rubber material includes the side reinforcing rubber layer 17 on the outer side in the tread width direction and the inner side in the tread width direction. Is arranged.

  Specifically, the outer triaxial fabric layer 18out is disposed outside the side reinforcing rubber layer 17 in the tread width direction, and the inner triaxial fabric layer 18in is disposed inside the side reinforcing rubber layer 17 in the tread width direction. .

The inner triaxial fabric layer 18in is obtained by coating the triaxial fabric 18 shown in FIG. 2 with a rubber material, like the outer triaxial fabric layer 18out. Further, the inner triaxial fabric layer 18in is set longer than the upper end 17ue and the lower end 17le of the side reinforcing rubber layer 17 by 5 mm or more in the cross section in the tread width direction. That is, the difference D ₁ ′ and the difference D ₂ ′ in the figure are set to 5 mm or more.

[Comparison / Evaluation]
Next, a comparative example, a test method for comparative evaluation of run-flat tires according to the first embodiment and the second embodiment (example) of the present invention, and the results thereof will be described.

(1) Test method and test conditions Comparative evaluation was performed on (i) longitudinal spring characteristics of run flat tires, (ii) ride comfort, and (iii) run flat performance.

  Regarding the vertical spring characteristics of the run flat tire, the amount of deflection of the sidewall portion of the run flat tire when a predetermined load (625 kg) was applied to the run flat tire was measured.

  As for the ride comfort, each run flat tire having an internal pressure set to 240 kPa was mounted on an SUV automobile (minivan), and the ride comfort was evaluated by the occupant in a state where two people got on.

  Specifically, the feeling when the test circuit was run at 80 km / h was evaluated as one of good (◯), normal (Δ), and defective (×).

  For run-flat performance, each run-flat tire whose internal pressure is set to 0 kPa is rotated with a predetermined load (625 kg) applied using a drum testing machine, and the running distance until the run-flat tire breaks down is measured. It was measured.

  In addition, about the longitudinal spring characteristic and run flat performance of a run flat tire, the other example of the run flat tire (comparative example, Example 1 and Example 2) was relatively evaluated by setting the conventional example to “100”.

(2) Test Results Table 1 shows the specifications of the run-flat tires according to the conventional example, the comparative example 1, the comparative example 2, the example 1 and the example 2, and the results of the test related to the comparative evaluation.

  As shown in Table 1, in the run flat tires according to Example 1 and Example 2, the thickness T of the side reinforcing rubber layer 17 is set by using the outer triaxial fabric layer 18out and the inner triaxial fabric layer 18in. Since it can be made thinner, the weight of the run flat tire (tire weight) is reduced compared to the run flat tire according to the conventional example.

  Further, in the run flat tires according to Example 1 and Example 2, since the thickness T of the side reinforcing rubber layer 17 can be reduced, the length of the run flat tire is longer than that of the run flat tire according to the conventional example. Spring characteristics are also reduced. That is, it is relieved that the run flat tire becomes hard in the vertical direction.

  For this reason, also about evaluation of riding comfort, the run flat tire which concerns on Example 1 and Example 2 exceeds the run flat tire which concerns on a prior art example.

  Furthermore, the use of the outer triaxial woven fabric layer 18out and the inner triaxial woven fabric layer 18in improves the durability against the load on the sidewall portion. The run flat tire according to No. 1 exceeds the run flat tire according to the conventional example.

  In particular, the run flat tire according to the second embodiment including the outer triaxial fabric layer 18out and the inner triaxial fabric layer 18in is compared with the run flat tire according to the first embodiment including only the outer triaxial fabric layer 18out. The flat performance is further improved.

  On the other hand, in the run-flat tire according to the comparative example, the outer triaxial fabric layer 18out and the inner triaxial fabric layer 18in are not used, and by increasing the thickness T of the side reinforcing rubber layer 17, It is configured to withstand loads such as vehicle weight. For this reason, the tire weight increases and the ride comfort deteriorates.

[Action / Effect]
According to the run flat tires 10 and 10 'according to the first and second embodiments of the present invention described above, the outer triaxial fabric layer 18out is provided, so that shear deformation of the side reinforcing rubber layer 17 is suppressed. Is done.

  Specifically, during the run-flat running, the side reinforcing rubber layer 17 is greatly bent, so that the “inside” portion of the side reinforcing rubber layer 17 in the tread width direction is compressed. On the other hand, the “outer” portion of the side reinforcing rubber layer 17 in the tread width direction is pulled.

  For this reason, shear deformation occurs in the side reinforcing rubber layer 17 and heat generation of the side reinforcing rubber layer 17 increases. When the heat generation of the side reinforcing rubber layer 17 is increased, bubbles are generated in the side reinforcing rubber layer 17, so that the elastic modulus of the side reinforcing rubber layer 17 is reduced and the rubber constituting the side reinforcing rubber layer 17 is destroyed.

  According to the run flat tires 10 and 10 ′, the portion of the side reinforcing rubber layer 17 on the “outer side” in the tread width direction is suppressed from being pulled and deformed, and thus the heat generation of the side reinforcing rubber layer 17 is also suppressed.

  That is, the rubber constituting the side reinforcing rubber layer 17 is suppressed from being broken, and durability against run flat running (run flat performance) is improved. In particular, according to the run-flat tires 10 and 10 ', durability against run-flat running is ensured when the run-flat tires 10 and 10' are mounted on a vehicle having a high designated tire height and a heavy vehicle weight, such as an SUV vehicle. Can be secured.

  Further, according to the triaxial woven fabric 18, since the reinforcing layer having high shear rigidity and rigidity distribution close to isotropic can be realized by only one layer, the weight of the run flat tires 10, 10 ′ is increased. The run-flat performance can be improved without causing it. For this reason, the deterioration of the riding comfort at the normal time and during the run-flat running is suppressed.

  The “reinforced canvas layer” used in conventional side-reinforced run-flat tires has the shear rigidity necessary to function as a reinforcing layer unless two or more canvases made of organic fibers are laminated. I couldn't do it. Further, in the run flat tire having the reinforced canvas layer, specific coupling deformation occurs, and the deformation amount increases in the direction of low shear rigidity, and a desired run flat performance cannot be ensured.

  Furthermore, in order to realize a reinforced canvas layer having a uniform rigidity distribution in all directions, at least three or more canvases had to be laminated.

  Further, according to the run flat tire 10 ′ according to the second embodiment of the present invention, the inner triaxial fabric layer 18 in is provided on the inner side in the tread width direction of the carcass layer 12 in addition to the outer triaxial fabric layer 18 out.

  That is, according to the run flat tire 10 ′, it is possible to suppress the portion of the side reinforcing rubber layer 17 “inside” in the tread width direction from being compressed and deformed. That is, the rubber constituting the side reinforcing rubber layer 17 is further prevented from being broken, and the durability against run-flat running is further improved.

  According to the run flat tires 10, 10 ′, the outer triaxial fabric layer 18out and the inner triaxial fabric layer 18in are longer than the upper end 17ue and the lower end 17le of the side reinforcing rubber layer 17 by 5 mm or more. Separation of the outer triaxial fabric layer 18out and the inner triaxial fabric layer 18in starting from the end of the inner triaxial fabric layer 18in is suppressed.

  According to the run flat tires 10 and 10 ', since the thickness T of the thickest portion of the side reinforcing rubber layer 17 is 15 mm or less, an increase in the vertical spring characteristics of the run flat tires 10 and 10' is avoided. . Furthermore, since the thickness T of the thickest portion of the side reinforcing rubber layer 17 is 15 mm or less, an increase in the weight of the run-flat tires 10, 10 'is also suppressed.

  For this reason, it is possible to improve the riding comfort of an SUV vehicle or the like to which the run flat tires 10, 10 'are mounted. As shown in Table 1, when the thickness T of the side reinforcing rubber layer 17 exceeds 15 mm, the run-flat performance is further improved, but the ride comfort is deteriorated, which is not preferable.

  According to the run-flat tires 10, 10 ', the carcass layer 12 is constituted by two layers of carcass, and therefore, an increase in the weight of the run-flat tires 10, 10' is suppressed. When the carcass layer 12 is composed of three or more carcass, the weight of the run-flat tires 10, 10 ′ is increased compared to the degree of improvement in durability when the internal pressure of the run-flat tires 10, 10 ′ increases. Deterioration of ride comfort due to is severe, which is not preferable.

[Other Embodiments]
As described above, the contents of the present invention have been disclosed through the first and second embodiments of the present invention. However, it should not be understood that the description and drawings constituting a part of this disclosure limit the present invention. Absent. From this disclosure, various alternative embodiments, examples and operational techniques will be apparent to those skilled in the art.

  For example, the embodiment of the present invention can be modified as follows. 4A and 4B are partially enlarged cross-sectional views in the tread width direction of the run flat tire 20 and the run flat tire 20 'according to the modified example of the present invention.

  As shown in FIG. 4A, the end portion 28 oe located on the bead portion 11 side of the triaxial fabric layer 28 out provided in the run-flat tire 20 is folded back at the bead portion 11 and is more than the carcass layer 12. Located on the outside in the tread width direction.

  Moreover, as shown in FIG.4 (b), the edge part 28oe located in the bead part 11 side of the triaxial fabric layer 28out provided in run flat tire 20 ', and the bead part 11 side of the triaxial fabric layer 28in The end portion 28ie located at the end is folded back at the bead portion 11 and is located outside the carcass layer 12 in the tread width direction.

  Since the end portion 28oe and the end portion 28ie are folded back at the bead portion 11 and are located on the outer side in the tread width direction than the carcass layer 12, the triaxial fabric layer 28out, triaxial from the end portion 28oe or the end portion 28ie as a starting point The separation of the fabric layer 28in is further suppressed.

  Further, as described above, the run flat tires 10, 10 ′ (and the run flat tires 20, 20 ′) are effective to be mounted on a vehicle having a high designated tire height and a heavy vehicle weight such as an SUV-based automobile. However, the present invention can also be applied to run flat tires mounted on other vehicles such as passenger cars.

  As described above, the present invention naturally includes various embodiments that are not described herein. 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.

It is a partial cross section figure in the tread width direction of the run flat tire concerning a 1st embodiment of the present invention. It is a figure which shows the structure of the triaxial fabric which comprises the triaxial fabric layer of the run flat tire which concerns on 1st Embodiment of this invention. It is a partial cross section figure in the tread width direction of the run flat tire concerning a 2nd embodiment concerning the embodiment of the present invention. It is a partially expanded sectional view in the tread width direction of the run flat tire which concerns on the example of a change of this invention.

Explanation of symbols

DESCRIPTION OF SYMBOLS 10,10 '... Run flat tire, 11 ... Bead part, 11a ... Bead core, 11b ... Bead filler, 12 ... Carcass layer, 13a, 13b ... Belt layer, 14 ... Cap layer, 15sw ... Side wall part, 15tr ... Tread part , 16 ... inner liner, 17 ... side reinforcing rubber layer, 17le ... lower end, 17ue ... upper end, 18 ... triaxial woven fabric, 18in ... inner triaxial woven fabric layer, 18out ... outer triaxial woven fabric layer, 18X, 18Y, 18Z ... cord 20, 20 '... run flat tire, 28ie ... end, 28in ... triaxial fabric layer, 28oe ... end, 28out ... triaxial fabric layer, CL ... tire equator line

Claims (6)

In the sidewall portion, a run-flat tire provided with a side reinforcing rubber layer that is disposed inward in the tread width direction than the carcass layer supported by the pair of bead portions and has a crescent-shaped cross-sectional shape in the tread width direction,
A triaxial fabric layer in which a triaxial fabric in which cords arranged along three axial directions intersecting each other are woven together is covered with a rubber material is provided on the outer side in the tread width direction of the side reinforcing rubber layer. Run flat tires.   The run-flat tire according to claim 1, wherein the triaxial fabric layer is disposed on the outer side in the tread width direction and on the inner side in the tread width direction of the side reinforcing rubber layer.   3. The run-flat tire according to claim 1, wherein the triaxial fabric layer has a cross section in the tread width direction that is 5 mm or more longer from an upper end and a lower end of the side reinforcing rubber layer.   The run flat tire according to any one of claims 1 to 3, wherein a thickness of the thickest portion of the side reinforcing rubber layer is 15 mm or less in a cross section in the tread width direction.   The run-flat tire according to any one of claims 1 to 4, wherein the carcass layer includes two or less carcass. 6. The end of the triaxial woven fabric layer located on the bead portion side is folded back at the bead portion and located on the outer side in the tread width direction than the carcass layer. The run flat tire according to one item.

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