JP2004345509A - Tire wheel assembly - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To improve the durability of a tire wheel assembly of a run-flat tire, particularly of an elastic ring constituting its core body, and to reduce its weight. <P>SOLUTION: This tire wheel assembly is equipped with the core body for run-flat constituted so that a thin and rigid annular shell is supported on a rim by the elastic ring in an inner hollow part of a tire/rim, a 100% modulus M (MPa) at 25°C of an elastic ring material is 4 to 40 and a product M×Eb with rupture elongation Eb(%) at 25°C is more than 2000. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

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【表２】

【００３３】
【表３】

【００３４】
【表４】

【００３５】
【発明の効果】
以上の通り、本発明に従えば、高剛性の環状シェルと弾性リングとによって形成されたランフラット用中子において、弾性リングを高モジュラスで高伸び性の材料で構成することにより耐久性が向上する。また、更に低発熱性の材料を用いることによって一層耐久性が向上する。これらの物性は具体的には例えば水素化ＮＢＲなどのエチレン性不飽和ニトリル−共役ジエン高飽和ゴムと（メタ）アクリル酸亜鉛などの（メタ）アクリル酸金属塩との配合物から得ることができ、また、必要最小限の弾性リングと環状シェルとの接着面積を確保すると一層好ましい。更に、これらの物性を有する弾性リング材を用いると、弾性リングに窪みや切り欠きのあるものも、リム組み中の損傷を防止でき、好ましく利用される。
【図面の簡単な説明】
【図１】本発明のタイヤホイール組立体の一例の要部を示す子午線断面図である。
【図２】本発明の好ましい態様におけるタイヤホイール組立体の弾性リングの一例を示す断面構成図で図２Ａは窪み部、図２Ｂは切欠き部を有する例である。
【符号の説明】
１…ランフラット用中子体
２…空気入りタイヤ
３…タイヤ／リムの内空洞部
４…高剛性環状シェル
５…弾性リング
６…リム
７…窪み
８…切欠き[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to a tire-wheel assembly for use in a pneumatic tire (hereinafter, referred to as a run-flat tire) that can perform limited operation in a damaged or deflated state, and more particularly, to a tire / rim provided in an inner cavity of a tire / rim. The present invention relates to a tire / wheel assembly in which a run-flat core body including a rigid annular shell and an elastic ring has improved durability and reduced weight.
[0002]
[Prior art]
Even if the internal pressure suddenly drops due to puncture, burst, etc., while the pneumatic tire is running, such as a car, there is a need for run-flat tires that can travel a certain distance and have an emergency running possibility. A proposal has been made. For example, in Patent Literature 1 and Patent Literature 2, a run-flat support (core) is mounted on a rim of an inner cavity of a pneumatic tire, thereby supporting a punctured pneumatic tire. Techniques that enable run-flat running have been proposed. Other disclosures of run flat tires are also found in Patent Documents 3 and 4.
[0003]
The run-flat core body has an annular member having an outer peripheral side as a support surface, and an elastic ring is attached to both legs thereof, such that the core body is supported on the rim of the tire via the elastic ring. Has a structure. In addition, this technology using a run flat core body allows the wheel / rim to be used as it is without any special modification to the wheel / rim of a conventional general pneumatic tire. It has the advantage that processing and mounting equipment can be used as it is.
[0004]
[Patent Document 1]
JP-A-10-297226 [Patent Document 2]
JP 2001-519279 A [Patent Document 3]
JP 2001-163020 A [Patent Document 4]
JP-A-1998-297226
[Problems to be solved by the invention]
The present invention improves the durability and weight of the run-flat core by using a material having a high elastic modulus and a high elongation for the elastic ring constituting the run-flat core of the run-flat tire wheel assembly. It is an object to provide an intended tire-wheel assembly.
[0006]
[Means for Solving the Problems]
According to the present invention, there is provided a tire / wheel assembly in which a run-flat core having a thin and rigid annular shell supported by the rim by an elastic ring is mounted in an inner cavity of the tire / rim. A tire-wheel assembly is provided in which the ring material has a 100% modulus M (MPa) at 25 ° C of 4 to 20 and a product M × Eb of the elongation at break at 25 ° C Eb (%) of greater than 2000.
[0007]
According to the present invention, the elastic ring material further comprises 100 parts by weight of a rubber component containing 50 parts by weight or more of an ethylenically unsaturated nitrile-conjugated diene-based highly saturated rubber having a conjugated diene unit content of 30% by weight or less. The tire-wheel assembly comprises a rubber composition containing 10 to 120 parts by weight of a metal salt of (meth) acrylic acid and an organic peroxide.
[0008]
BEST MODE FOR CARRYING OUT THE INVENTION
The present inventors have conducted research on a run-flat core body formed from a high-rigidity annular shell and an elastic ring, with the aim of improving the durability during run-flat and reducing the weight. As a result, when the material of the elastic ring is 100% modulus M (MPa) at 25 ° C. of 4 to 20, preferably 8 to 20, and the breaking elongation at 25 ° C. is E (%), the value of M × E is 2000. It has been found that the object can be achieved by using more than (M × E> 2000), preferably more than 3000 materials. Furthermore, it has been found that more preferable durability can be obtained by devising a contact area between the annular shell and the elastic ring in order to secure the adhesion between the elastic ring made of these materials and the rigid annular shell. The 100% modulus M (MPa) and elongation at break E (%) refer to values measured by the method of JIS K6251.
[0009]
According to the present invention, as described above, the higher the 100% modulus M (MPa) (25 ° C.) of the elastic ring material is, the smaller the deformation is, and the better the run flat durability is, so that this value may be 4 to 20 MPa. If necessary, 8 to 20 MPa is preferable. On the other hand, it is necessary to secure a minimum necessary elongation according to the amount of deformation of the elastic ring material. In consideration of this requirement, the product of 100% modulus M (25 ° C.) and Eb (%) (25 ° C.) When M × Eb exceeds 2000, preferably exceeds 3000, the durability is improved for the first time.
[0010]
In a preferred aspect of the present invention, when the tan δ (60 ° C.) of the elastic ring material is reduced, heat generation during run flat running is small, and the durability of the elastic ring itself is improved. The value of tan δ (60 ° C.) is sufficient to be 0.2 or less for a run flat life of about 100 km, but is preferably 0.15 or less, more preferably 0.10 or less. The value of tan δ was measured using a rheograph solid manufactured by Toyo Seiki Seisaku-Sho, Ltd. under the conditions of an initial strain of 10%, a dynamic strain of 2%, and a frequency of 20 Hz using a test sample having a width of 5 mm and a thickness of 2 mm. It was done.
[0011]
According to a preferred embodiment of the present invention, in order to facilitate the rim assembling at the time of manufacturing the tire, in the cross-sectional shape of the elastic ring 5, for example, as shown in FIGS. Can be. Generally, when such processing is performed, local stress concentration is likely to occur. However, if the elongation characteristic is ensured, such a problem does not occur, and the elastic ring is not damaged at the time of assembling the rim.
[0012]
Hereinafter, the present invention will be specifically described with reference to an example of a tire wheel assembly of the present invention shown in the drawings. FIG. 1 is a meridian sectional view showing a main part of a typical embodiment of a tire-wheel assembly (wheel) of the present invention.
[0013]
For example, as shown in FIG. 1, a run-flat core 1 according to the present invention comprises a high-rigidity annular shell 4 and an elastic ring 5 inserted into an inner cavity 3 of a tire / rim of a pneumatic tire 2. It is formed. The run-flat core 1 has a shape smaller than the inner diameter of the cavity 3 so that the outer diameter is kept at a certain distance from the inner surface of the inner cavity 3 of the pneumatic tire 2, and the inner diameter is generally Are formed to have dimensions substantially the same as the inner diameter of the bead portion of the pneumatic tire. The run-flat core 1 is assembled with the pneumatic tire 2 together with the pneumatic tire 2 into a rim 6 of a wheel while being inserted inside the pneumatic tire 2 to form a tire-wheel assembly. If the pneumatic tire is punctured while the tire-wheel assembly is mounted on an automobile or the like while traveling, the punctured and crushed tire 2 is supported by the outer peripheral surface of the run-flat core 1. , And run-flat running becomes possible.
[0014]
The run flat core of the tire / wheel assembly of the present invention includes an annular shell 4 and an elastic ring made of a highly rigid material (for example, a metal material such as iron, stainless steel, steel, or aluminum alloy, or a fiber-reinforced synthetic resin). The annular shell 4 forms a continuous support surface for supporting a punctured tire on the outside, and the inside has a shape with left and right side walls as legs. The outer support surface can take various shapes, for example, as shown in FIG. 1, such that the shape of a cross section orthogonal to the circumferential direction becomes a convex curved surface outward (the tire having the convex curved surface). The number arranged in the axial direction is not limited to two as shown in FIG. 1, but may be three or more, or even a single one), and may be flat or any other shape.
[0015]
The elastic rings 5 are attached to, for example, ends of both legs of the annular shell 4 and support the annular shell 4 by directly abutting on the left and right rims 6. The elastic ring 5 is usually made of rubber, and reduces shock and vibration applied to the annular shell 4 from a punctured tire or the like, acts as a non-slip for the rim 6, and stably supports the annular shell 4 on the rim 6. Work.
[0016]
In order to increase the adhesive strength between the high-rigidity annular shell 4 and the elastic ring 5 constituting the run-flat core 1, it is preferable to secure a predetermined adhesive area. The load at the time of rim work or run flat running is made dimensionless by the nominal inner diameter R (inch) of the tire, and when the bonding area is S (cm ² ), the ratio S / R is 4.5 cm ² / inch. More preferably, it is 8 to ²⁰ cm ² / inch. Here, the bonding area is the bonding area between the rigid material and the elastic ring at one end of the annular shell, that is, a table of the shell in contact with the elastic ring 5 at the end of the annular shell 4 in a cross section orthogonal to the circumferential direction. / It refers to the total bonding area where the back surface and the end surface make one round in the circumferential direction.
[0017]
Further, the bonding surface between the annular shell 4 and the elastic ring 5 is preferably formed in the axial direction and the radial direction, and it is more preferable that both are substantially equal. Thus, a structure is formed that can withstand both the axial and radial forces generated during run flat running. In FIG. 1, a run flat core 1, a pneumatic tire 2, and a rim 6 are formed coaxially annularly around a rotation axis (not shown) of a wheel. The size of the annular shell is not particularly limited, but preferably has a thickness of 0.5 to 3.0 mm and a width substantially equal to the interval between the right and left tire bead toes. In a preferred embodiment of the present invention, a recess as shown in FIG. 2A (preferable size is 50 to 100 mm in average diameter × 1/1 of the total thickness at the maximum depth) is provided on the outer side in the axial direction of the approximate center of the cross section of the elastic ring 5 in the radial direction. 4 to 1/3) and / or a notch as shown in FIG. 2B (preferably 1 to 3 mm in width × 1/2 to 1/3 of the total thickness) without adversely affecting the durability. When the rim is assembled, the elastic ring is easily deformed inward in the axial direction, so that the rim assemblability can be improved. In particular, it can be preferably used when using an elastic ring material having a high elastic modulus.
[0018]
As the elastic ring material of the tire-wheel assembly according to the present invention, an elastic material satisfying the above physical properties can be used. Specifically, the content of the conjugated diene unit is 30% by weight or less, preferably 0 to 20% by weight. 10 to 120 parts by weight, preferably 30 parts by weight of a metal salt of (meth) acrylic acid is added to 100 parts by weight of a rubber component containing at least 50 parts by weight, preferably 60 to 100 parts by weight of an ethylenically unsaturated nitrile-conjugated diene-based highly saturated rubber of A rubber composition containing up to 120 parts by weight and an organic peroxide can be used. If the amount of the ethylenically unsaturated nitrile conjugated diene-based highly saturated rubber is too small, the required modulus and elongation may not be obtained, and if the content of the conjugated diene unit is too large, the metal of (meth) acrylic acid may be insufficient. There is a possibility that the effect of the reinforcement with salt is reduced, and the required modulus cannot be obtained.
[0019]
The ethylenically unsaturated nitrile-conjugated diene-based highly saturated rubber that can be preferably used in the present invention is a known material as described in, for example, JP-A-63-270753 and JP-A-1-306440. More specifically, hydrogenated acrylonitrile-butadiene copolymer rubber manufactured by Zeon Corporation, Zetpol 0020, Zetpol 1010, Zetpol 1020, Zetpol 2000, Zetpol 2000L, Zetpol 2010, Zetpol 2010L, Zetpol 2010, Zetpol 20 Zetpol 2020L, Zetpol 2030L, Zetpol 3110, Zetpol 3120, Zetpol 4110, Zetpol 4120, and the like. Here, the "highly saturated rubber" refers to one obtained by partially or almost entirely hydrogenating a double bond of a diene portion.
[0020]
The metal salt of (meth) acrylic acid used in the present invention is, for example, a metal salt of acrylic acid or methacrylic acid. The metal is not particularly limited as long as it forms a salt with these, but zinc, magnesium , Calcium and aluminum are suitable. Among these combinations, zinc acrylate or zinc methacrylate is particularly preferred. If the amount of the metal salt of (meth) acrylic acid is too small, the required modulus and strength may not be obtained. Conversely, if the amount is too large, the metal may be too hard to deteriorate the rim assembling property or the required elongation. May not be obtained.
[0021]
Examples of the organic peroxide used in the present invention include dicumyl peroxide, di-t-butyl peroxide, t-butylcumyl peroxide, benzoyl peroxide, 2,5-dimethyl-2,5-di (t -Butylperoxy) hexyne-3, 2,5-dimethyl-2,5-mono (t-butylperoxy) hexane, α, α'-bis (t-butylperoxy-m-isopropyl) benzene and the like. Can be The amount of these organic peroxides is not particularly limited, but is preferably 0.2 to 10 parts by weight, more preferably 1 to 8 parts by weight, per 100 parts by weight of the rubber component.
[0022]
Examples of the rubber component blended with the rubber composition together with the ethylenically unsaturated nitrile-conjugated diene-based highly saturated rubber include natural rubber (NR), epoxidized natural rubber, and diene-based rubber (eg, polyisoprene rubber (IR), Polybutadiene rubber (BR), conjugated diene-aromatic vinyl copolymer (eg, SBR), ethylenically unsaturated nitrile-conjugated diene copolymer (eg, NBR) and hydrogenated products thereof, olefin rubber (ethylene-propylene rubber) (EPDM or EPM), maleic acid-modified ethylene-propylene rubber (M-EPM), butyl rubber (IIR), copolymer of isobutylene and aromatic vinyl or diene monomer), acrylic rubber (ACM), ionomer, halogen-containing rubber ( For example, CIIR, BIIR, isobutylene-p-methylstyrene copolymer Bromide (Br-IPMS), chloroprene rubber (CR), hydrin rubber (CHR, CHC), chlorosulfonated polyethylene (CSM), chlorinated polyethylene (CM), maleic acid-modified chlorinated polyethylene (M-CM)), Sulfur rubber (for example, polysulfide rubber) and fluorine rubber (for example, vinylidene fluoride rubber, fluorine-containing vinyl ether rubber, tetrafluoroethylene-propylene rubber, and fluorine-containing phosphazene rubber) can be given. In these rubber components, fillers such as carbon black, silica, calcium carbonate, and clay, antioxidants, oils or plasticizers, vulcanizing agents, vulcanization accelerators, general-purpose additives such as vulcanization aids are appropriately used. It can be used in combination.
[0023]
According to the present invention, a method of compounding an ethylenically unsaturated nitrile-conjugated diene highly-saturated rubber in a rubber component, and further a method of mixing a metal salt of (meth) acrylic acid and an organic peroxide thereto are as follows. It is.
That is, an acrylonitrile-butadiene copolymer and the remaining rubber component are first charged into a Banbury mixer having a capacity of 16 liters, and then zinc (meth) acrylate is charged and uniformly dispersed, and then a compounding agent other than the vulcanizing agent is added. Charged and mixed and released for a total of 3-5 minutes. Next, an organic peroxide was mixed with the rubber using an open roll to obtain a rubber composition.
[0024]
The material constituting the elastic ring 5 of the present invention further includes a reinforcing filler such as carbon black or silica, a vulcanizing or cross-linking agent, a vulcanizing or cross-linking accelerator, various oils, an antioxidant, a filler, a plastic, Various additives commonly used for general rubbers can be compounded, and the compounding amounts of these additives are also the same as conventional general compounding amounts, as long as they do not contradict the purpose of the present invention. It can be.
[0025]
【Example】
Hereinafter, the present invention will be further described with reference to Examples, but it goes without saying that the scope of the present invention is not limited to these Examples.
[0026]
Examples 1 to 15 and Comparative Examples 1 to 3
A tire / wheel assembly was prepared by the conventional method with the composition (parts by weight) shown in Tables I to IV and a tire size of 205 / 55R16 89V and a rim size of 16 × 6 1 / 2JJ, and was subjected to the following tests.
[0027]
Each of the test tire / wheel assemblies was subjected to a durability evaluation test by the following measurement method. The results are shown in Tables I-IV.
[0028]
100% modulus (M) (25 ° C) (MPa): Measured in accordance with JIS K6251. Elongation at break (Eb) (25 ° C.) (%): Measured in accordance with JIS K6251.
tan δ: Measured using a viscoelastic spectrometer manufactured by Toyo Seiki Seisakusho at 60 ° C., initial strain 10%, amplitude ± 2%, and frequency 20z.
[0029]
Rim assembling property: The rim is disassembled after assembling to check for damage to the core. Those that can run 100 km or more at 90 km / h and run flat are considered acceptable.
[0030]
Run flat durability: The test tire was mounted on a 2500 cc passenger car, the tire pressure on the front right side was set to 0 kPa, and the tire pressure at the other three places was set to 200 kPa, and the tire was allowed to run until it broke down, and the running distance was measured. . The results are shown in Tables I-IV.
[0031]
[Table 1]

[0032]
[Table 2]

[0033]
[Table 3]

[0034]
[Table 4]

[0035]
【The invention's effect】
As described above, according to the present invention, in the run-flat core formed by the high-rigidity annular shell and the elastic ring, the durability is improved by configuring the elastic ring with a high modulus and high elongation material. I do. Further, by using a material having a lower heat generation, the durability is further improved. These properties can be specifically obtained, for example, from a blend of an ethylenically unsaturated nitrile-conjugated diene highly saturated rubber such as hydrogenated NBR and a metal (meth) acrylate such as zinc (meth) acrylate. In addition, it is more preferable to secure a minimum required bonding area between the elastic ring and the annular shell. Furthermore, if an elastic ring material having these physical properties is used, an elastic ring having a dent or a notch can be prevented from being damaged during rim assembly, and is preferably used.
[Brief description of the drawings]
FIG. 1 is a meridian sectional view showing a main part of an example of a tire and wheel assembly of the present invention.
FIG. 2 is a cross-sectional view showing an example of an elastic ring of a tire-wheel assembly according to a preferred embodiment of the present invention. FIG. 2A shows an example having a concave portion, and FIG. 2B shows an example having a notched portion.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 1 ... Run flat core 2 ... Pneumatic tire 3 ... Inner cavity of tire / rim 4 ... Highly rigid annular shell 5 ... Elastic ring 6 ... Rim 7 ... Depression 8 ... Notch

Claims (7)

In a tire / wheel assembly having a run-flat core formed such that a thin rigid annular shell is supported on the rim by an elastic ring in the inner cavity of the tire / rim, the elastic ring material at 25 ° C. A tire / wheel assembly having a 100% modulus M (MPa) of 4 to 20, and a product M × Eb of the elongation at break at 25 ° C. Eb (%) of greater than 2000. The assembly according to claim 1, wherein the elastic ring material has a tan δ (60 ° C) of less than 0.20. The elastic ring material contains at least 50 parts by weight of an ethylenically unsaturated nitrile-conjugated diene-based highly-saturated rubber having a conjugated diene unit content of 30% by weight or less, and 100 parts by weight of a rubber component. The assembly according to claim 1, comprising a rubber composition containing 10 to 120 parts by weight of a salt and an organic peroxide. The assembly according to claim 3, wherein the content of the conjugated diene unit is 20% by weight or less and the amount of the metal salt of (meth) acrylic acid is 30 to 100 parts by weight. The tire according to any one of claims 1 to 4, wherein a ratio S / R between a nominal inner diameter R (inch) of the tire and an adhesion area S (cm ² ) of rubber / metal is 4.5 cm ² / inch or more. Wheel assembly. The assembly according to claim 5, wherein the bonding surface is constituted by a substantially axial surface and a substantially radial surface. The assembly according to any one of claims 1 to 6, wherein a cross-sectional shape of the elastic ring has a depression and / or a notch at a substantially central portion in a radial direction.

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