JP2008189131A - Run flat tire, and assembly of run flat tire and rim - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a run flat tire with a relatively simple structure having a lighter weight as compared with prior art while a conventional rim can be used. <P>SOLUTION: The run flat tire 1 has a pair of bead parts 3 buried with a bead core 2; a pair of side wall parts 4 extending from the bead part 3 to an outer side in a tire radial direction; and a tread part 5 extended astride between both side wall parts 4. Between both bead parts 4, an expandable annular partition membrane 6 for dividing a space partitioned between a tire and a rim 7 when the tire 1 is attached to the rim 7 to two chambers of an inner side chamber 8 in a tire radial direction and an outer side chamber 9 is arranged. The inner side chamber 8 and the outer side chamber 9 are connected with each other through a means 10 for restricting a ventilation amount provided on the partition membrane 6. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to a run-flat tire that can be safely stopped even in a run-flat state in which the tire internal pressure has suddenly decreased due to puncture or the like, and can run for a certain distance, and an assembly of such a run-flat tire and rim, In particular, the weight and the versatility of such tires and assemblies are improved.

  Run-flat tires are tires that support the tire load on the shoulder by air bladders, foams, elastic bodies, cores, etc. Tires and the like that prevent the decrease are known. However, since these conventional run flat tires have a complicated structure, the defect rate is often increased and the production efficiency is often lowered. In some cases, it is necessary to prepare a dedicated rim having a valve for filling air into the air and a structure for attaching the core.

  As a run-flat tire having a relatively simple structure, for example, in Patent Documents 1 and 2, an inner space between a tire and an inner chamber adjacent to a rim is formed by an inflatable annular diaphragm disposed between both bead portions. The tire divided into two chambers of the outer chamber adjacent to the inner surface of the tread portion is described. In such a tire, when the inner chamber and the outer chamber are filled with air, normal running is performed, and when the air in the outer chamber is released by puncture or the like and the internal pressure is reduced, the inner chamber is maintained until the diaphragm contacts the tire inner surface. Runflat running is enabled by the expansion of the air.

Japanese Patent Publication No. 37-1754 US Pat. No. 3,018,813

  However, the run-flat tire described in Patent Document 1 requires a valve for filling the outer chamber with air in the sidewall portion of the tire, which complicates the tire manufacturing process, There was a problem that the weight increased and the performance of the tire such as uniformity was impaired. Moreover, since the run-flat tire described in Patent Document 2 has a large outer diameter of the diaphragm, the tire inner surface and the diaphragm come into contact with each other when the protrusion is overcome during running, and as a result, the diaphragm may be damaged. there were.

  Therefore, the present invention has an object to solve such problems of the prior art, and its purpose is that the structure is relatively simple and the conventional rim can be used. The object is to provide a run-flat tire that is more durable than the prior art.

  In order to achieve the above object, a run flat tire according to the present invention straddles a pair of bead portions in which a bead core is embedded, a pair of sidewall portions extending outward from the bead portion in the tire radial direction, and both sidewall portions. In a run flat tire having an extending tread portion, an inflatable annular tire that divides a space defined between the tire and the rim into two chambers inside and outside in the tire radial direction when the tire is mounted on the rim. A diaphragm is provided, and the inner chamber and the outer chamber communicate with each other through a means for restricting the amount of air provided in the diaphragm. By adopting such a configuration, even when the tire is punctured, only the air in the outer chamber is released, and the air in the inner chamber expands to take over the load support, thereby enabling run-flat running. In addition, since the structure is obtained by adding a diaphragm to the conventional tire, the structure is relatively simple and light. Furthermore, since air can be supplied from the inner chamber to the outer chamber via the filter, it can be mounted on a conventional rim. In addition, there is little risk that the diaphragm will contact the tire inner surface, and there is little risk of damage.

  As long as the diaphragm is mounted on the rim, the diaphragm may be disposed so as to divide a space defined between the tire and the rim into two chambers on the inner side and the outer side in the tire radial direction. It is preferably disposed between both bead portions, and for example, both width end portions are disposed so as to be pressed against the rim when the rim is mounted.

  Further, as the air flow restriction means, the air flow between the inner chamber and the outer chamber can be communicated, that is, the air flow between the inner chamber and the outer chamber can be restricted, and the differential pressure can be adjusted. Although there is no particular limitation as long as it is present, it is necessary to maintain the communication between the inner chamber and the outer chamber without blocking, and it is preferable to use a filter means or a small hole from the viewpoint of weight reduction.

When using the filter unit as aeration regulating means, it is preferable to use a nonwoven fabric, particularly preferably within the range having a basis weight of 5 to 1000 g / m ² as the nonwoven fabric.

  When a small hole is used as the air flow restriction means, the diameter is preferably in the range of 0.5 to 5 mm.

  Further, the air flow restriction means preferably adjusts the internal pressure of the inner chamber to be equal to or higher than the internal pressure of the outer chamber while the tire is mounted on the rim and filled with a predetermined internal pressure. It is more preferable to adjust within the range of 100 to 110%. By adjusting the differential pressure in this manner, the air in the inner chamber can be rapidly expanded when the internal pressure is reduced while preventing the diaphragm from coming into contact with the rim and the tire inner surface and being damaged.

  The run-flat tire and rim assembly according to the present invention is obtained by mounting any of the above-described run-flat tires on the rim.

  According to the present invention, since the load is supported when the internal pressure is reduced with a simple structure as compared with the conventional run-flat tire, the weight can be reduced and the conventional rim can be mounted. Therefore, versatility is improved.

Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 is a cross-sectional view in the tire width direction of a tire-rim assembly formed by mounting a typical run-flat tire (hereinafter referred to as “tire”) according to the present invention on a rim, before and after applying internal pressure. FIG. 2 shows a state where the internal pressure of the tire shown in FIG.

  The tire 1 of the illustrated embodiment includes a pair of bead portions 3 in which a bead core 2 is embedded, a pair of sidewall portions 4 extending outward in the tire radial direction from the bead portion 3, and between the sidewall portions 4, 4. It has a tread portion 5 extending over. Although not shown, the tire also has other tire constituent members such as a carcass and a belt layer in accordance with the custom.

  An inflatable annular diaphragm 6 is disposed inside the tire over the entire circumference of the tire. The diaphragm 6 has a space defined between the tire 1 and the rim 7 when the tire 1 is mounted on the rim 7. It is divided into two chambers, which are located on the outer side of the tire and adjacent to the inner surface of the tire 1. Further, the diaphragm 6 is provided with a filter means 10 which is a means for regulating the air flow between the inner chamber 8 and the outer chamber 9, and the inner chamber 8 and the outer chamber 9 communicate with each other via the filter means 10. ing. The diaphragm 6 can be made of an air-impermeable and extensible material such as rubber, a composite of rubber and nonwoven fabric, or a resin such as TPO (olefinic thermoplastic elastomer). In consideration of the expansion (breaking elongation) of the diaphragm 6 when the internal pressure decreases, it is preferable to use TPO. Moreover, it is preferable that the thickness of the diaphragm 6 exists in the range of 1-3 mm. The reason is that when the thickness is less than 1 mm, the diaphragm 6 may interfere with foreign matter when contacting the tire inner surface, and the diaphragm may be damaged. As a result, the tire performance such as fuel efficiency may be impaired.

  When air is supplied to the inner chamber 8 via the air filling valve 11 provided on the rim 7, a part of the supplied air is supplied to the outer chamber 9 via the filter means 10. Then, when the supply of air is stopped when the internal pressure of the inner chamber 8 reaches a predetermined value, the differential pressure is adjusted by the filter means 10. In a state where the internal pressure is normal, the diaphragm 6 is maintained in the non-contact state shown in FIG. 1 with respect to the inner surface of the tread portion 5 and the rim 7, and thus is not damaged by rubbing or the like.

  When the tire is damaged by puncture or the like and the air in the outer chamber 9 flows out and the internal pressure decreases, the air in the inner chamber 8 expands and the diaphragm 6 comes into contact with the inner surface of the tire, as shown in FIG. It becomes a state. As a result, the load applied to the tire is supported by the air in the inner chamber 8 instead of the shoulder, so that it is possible to perform run-flat traveling safely at least until the vehicle completely stops. The diaphragm 6 is provided with means for restricting the amount of ventilation such as filter means and small holes to be described later. However, even when the internal pressure of the outer chamber 9 suddenly decreases, the amount of ventilation is restricted. Since it takes time for the internal pressure of the chamber 8 to decrease, the diaphragm 6 expands due to a change in the differential pressure.

  As described above, according to the present invention, since a filling valve for filling the outer chamber 9 with air is not required, a conventional rim can be used, and it is relatively easy to use a pneumatic tire having a general structure. A run-flat tire can be constructed simply by adding a lightweight diaphragm 6 that has a simple structure. Therefore, a metallic core is placed in the tire or a sealant is filled in the inner space of the tire. Compared to the conventional run-flat tire, the weight can be significantly reduced.

  As the filter means 10, the filter means 10 is comprised by making a hole in the material which comprises the diaphragm 6, and covering this hole with a nonwoven fabric. Thus, using non-woven fabric as the filter means can further reduce the weight compared to the case where a valve is used, and there is little difference in mass between the part where the filter means is provided and the part where the filter means is not provided, and the tire uniformity is reduced. There is no loss. In addition, since the nonwoven fabric is a porous sheet in which fibers are overlapped and bonded in a three-dimensional structure, smooth air flow between the inner chamber and the outer chamber is not obstructed, but the differential pressure due to pressure loss is reduced. It can occur between the inner chamber and the outer chamber. And this differential pressure | voltage can be adjusted by selecting the fabric weight of a nonwoven fabric suitably.

  The nonwoven fabric applicable to the present invention is not particularly limited as long as it can generate a differential pressure due to pressure loss between the inner chamber and the outer chamber. For example, natural fiber, synthetic fiber, glass fiber, metal A fiber, carbon fiber, or the like bonded by spun bond, thermal bond, chemical bond, needle punch, stitch bond, or the like can be used. A particularly suitable nonwoven fabric is a PET fiber bonded with a rubber bond.

  In addition, although the figure showed the example which provided the filter means 10 on the substantially equatorial plane of the tire, the arrangement | positioning position is not limited to this, For example, it may arrange | position so that the side wall part 4 may be opposed. it can. The size and number of the filter means can be appropriately increased or decreased according to the tire size, the internal pressure during use, the strength of the nonwoven fabric, and the like.

When a non-woven fabric having a high basis weight is used, the flow rate of air that can pass through this is limited. Therefore, when air is supplied through the air filling valve 11, the difference between the inner chamber 8 and the outer chamber 9 temporarily. The pressure increases and the diaphragm 6 may be deformed beyond the yield point. From the viewpoint of preventing this, the basis weight of the nonwoven fabric is preferably 1000 g / m ² or less. On the other hand, since the nonwoven fabric with a low basis weight has low strength, it is preferable that the basis weight of the nonwoven fabric is 5 g / m ² or more from the viewpoint of securing the strength of the entire diaphragm 6.

FIG. 3 shows a cross section in the tire width direction of an assembly of a tire and a rim formed by mounting another tire according to the present invention on the rim, before and after applying the internal pressure. In addition, the same code | symbol is used for the same part as the tire of the Example shown in FIG. 1, and the description is abbreviate | omitted.

  In this embodiment, a small hole 12 is provided in the diaphragm 6 as a ventilation amount regulating means. Accordingly, as in the case of using the filter means, a filling valve for filling the outer chamber 9 with air is not required, so that a conventional rim can be used, and a pneumatic tire having a general structure is used. Since a run-flat tire can be constructed simply by adding a relatively simple and lightweight diaphragm 6, a metallic core can be arranged in the tire or a sealant agent can be filled in the inner space of the tire. Compared to conventional run-flat tires, the weight can be significantly reduced. In addition, the weight can be further reduced as compared with the case where a valve is used, and the difference in mass between the portion provided with the small hole and the portion not provided is small, and the uniformity of the tire is not impaired. Furthermore, although it does not hinder the smooth air flow between the inner chamber and the outer chamber, a differential pressure due to pressure loss can be generated between the inner chamber and the outer chamber. This differential pressure can be adjusted by appropriately selecting the diameter of the small holes. The diameter of the small holes is preferably in the range of 0.5 to 5 mm. This is because if the diameter is less than 0.5 mm, the pressure in the inner chamber may increase too much when the inner pressure is filled, and the diaphragm may expand, and if it exceeds 5 mm, the outer chamber may be punctured. This is because, when the internal pressure of the engine is reduced, the air in the inner chamber and the air in the outer chamber also flow out of the tire, and the run-flat function may not be ensured.

  In order to continue traveling safely even when the internal pressure suddenly decreases, it is preferable that the tire can quickly shift to the run-flat traveling state, and therefore the diaphragm 6 is preferably expanded immediately when the internal pressure decreases. From this viewpoint, it is preferable that the inner pressure of the inner chamber 8 is equal to or higher than the inner pressure of the outer chamber 9. This is because the air in the inner chamber 8 expands simultaneously with the start of the decrease in internal pressure. However, if a large tension is applied to the diaphragm 6 in a normal running state, the diaphragm 6 may creep and deform and contact the tire inner surface when used for a long time. From the viewpoint of preventing this, it is preferable to set the internal pressure of the inner chamber 8 to 10% or less of the internal pressure of the outer chamber 9.

  Note that the above description shows only a part of the embodiment of the present invention, and these configurations can be combined with each other or various modifications can be made without departing from the gist of the present invention. . For example, a sealant can be applied to the outer peripheral surface of the diaphragm 6, and according to this, even if the diaphragm 6 expands while the nail or the like causing the puncture is stuck in the tire, it can be damaged. Can be prevented. Furthermore, an internal pressure sensor can be provided in at least one of the inner chamber 8 and the outer chamber 9 of the tire, and when the internal pressure decreases, the occurrence of an abnormality can be transmitted to the driver.

  As is clear from the above description, the present invention enables a light weight and can be mounted on a conventional rim by supporting the load when the internal pressure is reduced with a simple structure compared to a conventional run-flat tire. This makes it possible to provide a highly versatile run flat tire.

It is sectional drawing in the tire width direction of the tire and rim | limb assembly comprised by mounting | wearing the rim with the typical run flat tire according to this invention, and shows the state before and after applying an internal pressure. FIG. 2 is a tire width direction cross-sectional view of the run flat tire shown in FIG. 1 in a run flat running state in which the internal pressure is reduced. It is sectional drawing in the tire width direction of the tire and rim assembly comprised by mounting | wearing the rim with the other run flat tire according to this invention, and shows the state before and after applying an internal pressure.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Tire 2 Bead core 3 Bead part 4 Side wall part 5 Tread part 6 Diaphragm 7 Rim 8 Inner chamber 9 Outer chamber 10 Filter means 11 Air filling valve 12 Small hole

Claims (10)

In a run flat tire having a pair of bead portions in which a bead core is embedded, a pair of sidewall portions extending outward from the bead portion in the tire radial direction, and a tread portion extending between both sidewall portions,
An inflatable annular diaphragm is provided that divides a space defined between the tire and the rim into two chambers on the inner side and the outer side in the tire radial direction when the tire is mounted on the rim;
The run-flat tire according to claim 1, wherein the inner chamber and the outer chamber communicate with each other through a means for restricting the air flow provided in the diaphragm.   The run-flat tire according to claim 1, wherein the diaphragm is disposed between the bead portions.   The run-flat tire according to claim 1 or 2, wherein the air flow restriction means is a filter means.   The run-flat tire according to claim 3, wherein the filter means includes a nonwoven fabric. The run-flat tire according to claim 4, wherein the nonwoven fabric has a basis weight within a range of 5 to 1000 g / m ² .   The run-flat tire according to claim 1 or 2, wherein the air flow restriction means is a small hole.   The run-flat tire according to claim 6, wherein the small hole has a diameter in a range of 0.5 to 5 mm.   The air flow restriction means adjusts the internal pressure of the inner chamber to be equal to or higher than the internal pressure of the outer chamber in a state where a tire is mounted on a rim and a predetermined internal pressure is filled. The described run-flat tire.   The air flow restriction means adjusts the internal pressure of the inner chamber within a range of 100 to 110% of the internal pressure of the outer chamber in a state where a tire is mounted on a rim and a predetermined internal pressure is filled. The described run-flat tire.   The run-flat tire and rim assembly according to any one of claims 1 to 9.

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