JP4479335B2 - Lubricant for run flat support - Google Patents

Description

  The present invention relates to a lubricant used for a run-flat support that enables a tire to run flat, and more particularly to a lubricant for a run-flat support that can extend the life of a tire during run-flat travel. .

  Many technologies for enabling a certain degree of emergency traveling have been proposed in response to market demands even when a pneumatic tire punctures while the vehicle is traveling. The core (run flat support) is inserted into the cavity formed between the pneumatic tire and the wheel rim, and the flat tire can be supported by the core to enable run flat running. There is what I did.

When using such a run-flat support body, it is necessary to arrange a lubricating means at the contact portion between the outer surface of the support body and the inner surface of the tire in order to reduce damage to the tire due to run-flat running (for example, (See Patent Document 1 and Patent Document 2). However, even if the lubricating means is disposed at the contact portion between the outer surface of the support and the inner surface of the tire, sufficient durability cannot always be obtained. This is because the destruction of the tire is caused not only by the friction generated between the outer surface of the support and the inner surface of the tire, but also by the heat generated when the tire tread is greatly deformed by receiving a local load from the support. Because it does. Therefore, in order to improve the durability of the tire during run flat running, it is also important to suppress the heat generation.
JP-A-6-270617 Japanese Utility Model Publication No. 2-64405

  An object of the present invention is to provide a lubricant for a run-flat support body that can extend the tire life during run-flat running.

Lubricants for run-flat support member of the present invention that solve the above object, the grease-like lubricating component, a volatile material having a boiling point in the range of 60 ° C. to 90 ° C., was added in a state of enclosing the capsule it shall be the features a.

  The lubricant for the run-flat support according to the present invention is provided between the pneumatic tire and the run-flat support when the run-flat support is inserted into a cavity formed between the pneumatic tire and the wheel rim. Used as a lubricant between.

  Here, the lubricant for the run-flat support of the present invention has a lubricating action based on the lubricating component since a volatile substance having a boiling point in the range of 60 ° C. to 90 ° C. is added to the grease-like lubricating component. Of course, at the same time, the portion that generates heat during the run-flat running can be effectively cooled by the heat of vaporization of the volatile substance. As a result, it is possible to extend the tire life during run-flat running and to exhibit better run-flat running performance.

  As the volatile substance, at least one organic compound selected from the group consisting of cyclohexane, methyl alcohol, ethyl alcohol, methyl ethyl ketone, butyl chloride, thiophene, and trichloroethane can be used. The amount of these volatile substances added is preferably 5% by volume to 40% by volume with respect to the lubricating component.

The volatiles you added to the lubricating component in a state of being enclosed in a capsule. This capsule has a structure that collapses during run-flat travel and releases the encapsulated volatile substances. By volatile material was encapsulated in a capsule, it is possible to reliably hold the volatiles until the run-flat running is required.

  As a constituent material of the capsule, at least one polymer resin selected from the group consisting of a polyester resin, an ethyl cellulose resin, a urea resin, a methacrylic acid resin, and a polyurethane resin can be used.

  It is preferable to add a powder of a heat conductive material typified by metal powder to the lubricating component. When such a heat conductive substance powder is added, since the heat conduction efficiency of the lubricant is increased, the cooling effect by the volatile substance can be obtained quickly.

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

  FIG. 1 shows an example of a tire wheel assembly using a lubricant for a run-flat support according to the present invention. In FIG. 1, 1 is a wheel rim, 2 is a pneumatic tire, and 3 is a run-flat support. The rim 1, the pneumatic tire 2, and the run flat support 3 are formed in an annular shape around a wheel rotation axis (not shown). That is, the run-flat support 3 is inserted into a cavity formed between the pneumatic tire 2 and the wheel rim 1.

  The run-flat support 3 is composed mainly of an annular shell 4 and an elastic ring 5. The run flat support 3 is spaced apart from the inner wall surface of the pneumatic tire 2 during normal running, but supports the collapsed pneumatic tire 2 from the inside during puncture.

  The annular shell 4 projects a continuous support surface 4a for supporting a punctured tire to the outer peripheral side (radially outer side) and has leg portions 4b and 4b along both sides of the support surface 4a. It has become. The support surface 4a of the annular shell 4 is formed so that the shape in a cross section perpendicular to the circumferential direction thereof is a convex curved surface on the outer peripheral side. There are at least two convex curved surfaces in the tire axial direction, and a concave portion is formed between them. In this way, by forming the support surface 4a of the annular shell 4 so that two or more convex curved surfaces are arranged side by side, the contact portion of the support surface 4a with respect to the tire inner wall surface is dispersed into two or more, and the local portion is given to the tire inner wall surface. In order to reduce wear, the run distance of run-flat travel can be extended.

  The annular shell 4 is made of a rigid material because it needs to support the vehicle weight via the punctured pneumatic tire 2. As the constituent material, metal, resin, or the like is used. Among these, steel, aluminum, etc. can be illustrated as a metal. Further, the resin may be either a thermoplastic resin or a thermosetting resin. Examples of the thermoplastic resin include nylon, polyester, polyethylene, polypropylene, polystyrene, polyphenylene sulfide, and ABS. Examples of the thermosetting resin include an epoxy resin and an unsaturated polyester resin. The resin may be used alone, or may be used as a fiber reinforced resin by blending reinforcing fibers.

  The elastic ring 5 is attached to each of the leg portions 4 b and 4 b of the annular shell 4, and supports the annular shell 4 while contacting the rim 1 along the bead portion of the pneumatic tire 2. The elastic ring 5 reduces the impact and vibration received by the annular shell 4 from the punctured pneumatic tire 2 and prevents the rim 1 from slipping to stably support the annular shell 4.

  As a constituent material of the elastic ring 5, rubber or resin can be used, and rubber is particularly preferable. As rubber, natural rubber (NR), isoprene rubber (IR), styrene-butadiene rubber (SBR), butadiene rubber (BR), hydrogenated NBR, hydrogenated SBR, ethylene propylene rubber (EPDM, EPM), butyl rubber (IIR) ), Acrylic rubber (ACM), chloroprene rubber (CR), silicone rubber, fluorine rubber and the like. Of course, additives such as a filler, a vulcanizing agent, a vulcanization accelerator, a softening agent and an anti-aging agent can be appropriately blended with these rubbers. And a desired elasticity modulus can be obtained based on the mixing | blending of a rubber composition.

  In the tire-wheel assembly configured as described above, when the pneumatic tire 2 is punctured during traveling, the collapsed pneumatic tire 2 is supported by the annular shell 4 of the run-flat support 3. Driving is possible. However, during the run-flat running, the pneumatic tire 2 is destroyed by rubbing between the inner surface of the pneumatic tire 2 and the outer surface of the annular shell 4 of the run-flat support 3. Therefore, in the tire wheel assembly, the lubricant 6 is applied to the inner surface of the tread portion of the pneumatic tire 2.

FIG. 2 illustrates the lubricant referred to in the present invention . In FIG. 2, the lubricant 6 has a grease-like lubricating component 7 as a matrix, and a volatile substance 8 is dispersed in the lubricating component 7. 3 and 4 each illustrate the lubricant in the present invention. In FIG. 3, the lubricant 6 has a grease-like lubricating component 7 as a matrix, and a volatile substance 8 encapsulated in capsules 9 is dispersed in the lubricating component 7. In FIG. 4, the lubricant 6 has a grease-like lubricating component 7 as a matrix, and a volatile substance 8 encapsulated in a capsule 9 is attached to the surface of the lubricating component 7.

  Thus, the lubricant 6 is disposed between the pneumatic tire 2 and the run-flat support 3, and the volatile substance 8 is added to the grease-like lubricant component 7 of the lubricant 6. In addition to the lubricating action based on it, a cooling effect by the heat of vaporization of the volatile substance 8 can be obtained. As a result, it is possible to extend the tire life during run-flat running and to exhibit better run-flat running performance.

  The lubricating component of the lubricant 6 is not particularly limited. For example, a lubricant obtained by blending a mineral base oil or a synthetic base oil with a thickener, a silicone oil blended with a thickener, and the like. Can be mentioned.

  The volatile material of the lubricant 6 has a boiling point in the range of 60 ° C. to 90 ° C. at a standard atmospheric pressure, that is, a saturated vapor pressure exceeding the atmospheric pressure in the range of 60 ° C. to 90 ° C. Pressure). Since the tire temperature reaches the above range during run-flat running, a good cooling effect can be obtained during run-flat running by selecting a volatile substance having the above physical properties. In addition, if the boiling point of the volatile substance is 60 ° C. or higher, the evaporated volatile substance aggregates again at a relatively low temperature such as the rim surface, and a continuous cooling effect can be obtained during run-flat running. it can. Examples of the volatile substance (volatile liquid) include cyclohexane, methyl alcohol, ethyl alcohol, methyl ethyl ketone, butyl chloride, thiophene, and trichloroethane.

  The amount of the volatile substance added may be 5% by volume to 40% by volume with respect to the lubricating component. If the addition amount of the volatile substance is less than 5% by volume of the lubricating component, the cooling effect becomes insufficient. Conversely, if it exceeds 40% by volume, it becomes difficult to hold the volatile substance as a dispersed phase in the lubricating component. Become.

The volatiles you added to the lubricating component in a state of being enclosed in a capsule. For example, the capsule has a structure in which it is exposed to an atmosphere of 80 ° C. to 90 ° C. due to heat generated during run-flat running, or collapses by receiving external force during run-flat running and releases the encapsulated volatile substance. is there. By enclosing this way the volatile substance in the capsule, it is possible to reliably hold the volatiles until the run-flat running is required. In other words, if a long time elapses between the application of the lubricant and the occurrence of puncture, and the volatile substance has already evaporated at the time of occurrence of the puncture, the desired cooling effect cannot be obtained. The inclusion of the volatile substance can be avoided reliably. Examples of the constituent material of the capsule include polyester resin, ethyl cellulose resin, urea resin, methacrylic acid resin, and polyurethane resin .
In addition to the volatile material, a powder of a heat conductive material such as a metal powder can be added to the lubricating component of the lubricant 6. When the heat conductive substance powder is added, the heat conduction efficiency of the lubricant is increased, so that the cooling effect by the volatile substance can be obtained quickly. As the metal powder, powders of aluminum, copper, iron, nickel, zinc and the like can be used. Moreover, you may make it use powders, such as inorganic ceramics, such as an alumina and a silica, as a substance which has the high heat conductivity according to a metal.

  In the embodiment described above, when a run-flat support body composed of a pair of elastic rings and an annular shell straddling the elastic rings is inserted into the cavity formed between the pneumatic tire and the wheel rim. However, in the present invention, the structure of the run flat support is not particularly limited.

A pneumatic tire having a tire size of 205 / 55R16 and a wheel having a rim size of 16 × 6 1 / 2JJ, and a pair of elastic rings in the cavity formed between the pneumatic tire and the wheel rim, and the elastic ring In a tire wheel assembly in which a run-flat support body composed of a straddling annular shell is inserted, a tire wheel assembly in which a lubricant in which a volatile substance is added to a lubricating component is applied to the inner surface of a tread portion of a pneumatic tire (implemented) Examples 1-3 and Comparative Examples 1-3 ) were prepared. Moreover, the tire wheel assembly (conventional example) which apply | coated the lubricant containing only the same lubricating component as Examples 1-3 and Comparative Examples 1-3 for the inner surface of the tread part of a pneumatic tire was prepared for the comparison .

In Comparative Examples 1 to 3, cyclohexane (boiling point 81 ° C.) is used as the volatile substance, the volatile substance is directly dispersed in the lubricating component, and the amount of volatile substance added (volume% with respect to the lubricating component) varies. Let In Examples 1-3, using cyclohexane (boiling point 81 ° C.) as a volatile substance, is dispersed in the lubricating component in a state of enclosing the volatiles capsule volume to amount (lubricating component volatiles %) Were varied.

  With respect to the above seven types of tire wheel assemblies, durability during run flat running was evaluated by the following method, and the results are shown in Table 1.

[Durability during run-flat driving]
The tire wheel assembly to be tested is mounted on the front right wheel of a FR car with a displacement of 2.5 liters. The distance traveled until the vehicle became unable to travel was measured. The evaluation results are shown as an index with the conventional example being 100. The larger the index value, the better the durability during run-flat running.

この表１に示すように、実施例１〜３のタイヤホイール組立体はいずれもランフラット走行時の耐久性が従来よりも優れていた。

As shown in Table 1, the tire wheel assemblies of Examples 1 to 3 were all superior in durability during run-flat running.

It is meridian sectional drawing which shows an example of the tire wheel assembly using the lubricant for run flat supports of this invention. It is a sectional view showing a lubricant present invention refers. It is sectional drawing which shows an example of the lubricant in this invention. Another example of the lubricant in the present invention is a cross-sectional view illustrating.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Wheel rim 2 Pneumatic tire 3 Run flat support 4 Annular shell 5 Elastic ring 6 Lubricant 7 Lubrication component 8 Volatile substance 9 Capsule

Claims (6)

A lubricant for a run-flat support , in which a volatile substance having a boiling point in the range of 60 ° C. to 90 ° C. is added to a grease-like lubricating component in a state of being encapsulated .   The run-flat support lubricant according to claim 1, wherein the volatile substance is at least one organic compound selected from the group consisting of cyclohexane, methyl alcohol, ethyl alcohol, methyl ethyl ketone, butyl chloride, thiophene, and trichloroethane. Agent.   The run-flat support lubricant according to claim 1 or 2, wherein an addition amount of the volatile substance is 5 vol% to 40 vol% with respect to the lubricating component. The run according to claim 1, 2 or 3 , wherein the constituent material of the capsule is at least one polymer resin selected from the group consisting of polyester resin, ethyl cellulose resin, urea resin, methacrylic acid resin, and polyurethane resin. Lubricant for flat supports. The run-flat support lubricant according to any one of claims 1 to 4 , wherein a powder of a heat conductive material is added to the lubricant component. The run-flat support lubricant according to any one of claims 1 to 4 , wherein a metal powder is added to the lubricating component. .

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