JP2008308125A - Safety tire - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a safety tire with a relatively simple structure, capable of using a conventional rim, and superior in rim assembly performance while improving durability better than the conventional art. <P>SOLUTION: The safety tire 1 comprises a pair of bead parts 3 with bead cores 2 buried therein, a pair of side wall parts 4 extending from the bead parts 3 outwardly to the tire-radial direction, and a tread part 5 striding and extending between the both side wall parts 4, 4. An expansible annular diaphragm 6 is arranged between the both bead parts 3, 3 for fractionating a space demarcated between the tire 1 and the rim 7 when the tire 1 is mounted to the rim 7 into two chambers of an inner chamber 8 and an outer chamber 9 in the tire-radial direction. The diaphragm 6 is equipped with a communicating part 10 for communicating the inner chamber 8 and the outer chamber 9 while limiting flow velocity. Both width-end parts of the diaphragm 6 are inserted into annular grooves 11 formed at the bead parts 3 and fixed to the bead parts 3 by fitting ring-shaped fixing members 12 to the annular grooves 11. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to a safety 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 travel a certain distance, and in particular, to improve the rim assembly property of such a tire. .

  Safety tires include tires that support the tire load on the shoulders of air bladders, foams, elastic bodies, cores, etc., and the internal pressure is reduced by closing damaged parts such as holes created by applying or filling sealant. Tires and the like that prevent the above are known. However, since these conventional safety tires have a complicated structure, there are many cases where the defect rate increases and the production efficiency decreases. 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 safety tire having a relatively simple structure, for example, in Patent Document 1, an inflatable annular diaphragm disposed between both bead portions allows the inner space of the tire to be separated from the inner chamber adjacent to the rim and the tread portion of the tire. A tire divided into two chambers, an outer chamber adjacent to the inner surface, 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

  However, the safety 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 and increases the weight of the tire. There is a problem that the performance of tires such as uniformity is impaired.

  In order to solve such problems of the prior art, the applicant of Japanese Patent Application No. 2007-25527 defines a space defined between the tire and the rim when the tire is mounted on the rim in the tire radial direction. Propose a safety tire that has an inflatable annular diaphragm that is divided into two chambers on the inside and outside, and that communicates the inner chamber and the outer chamber through a means for regulating the air flow provided in the diaphragm. did. However, in such a safety tire, since the diaphragm is held between the tire and the rim, the rim is not easily assembled, and it is difficult to fix the diaphragm, and the diaphragm may come off the tire when the rim is mounted or used.

  Therefore, an object of the present invention is to solve these problems, and an object of the present invention is to have a relatively simple structure, to which a conventional rim can be used, and to be more durable than the prior art. An object of the present invention is to provide a safety tire excellent in rim assembly property while improving the performance.

  In order to achieve the above object, the present invention provides a safety tire having a pair of bead portions, a pair of sidewall portions extending outward in the tire radial direction from the bead portions, and a tread portion extending between both sidewall portions. The safety tire extends between the bead portions, and when the tire is mounted on the rim, the space defined between the tire and the rim is divided into two chambers on the inner side and the outer side in the tire radial direction. The diaphragm further includes a possible annular diaphragm, and the diaphragm includes at least one communication portion that communicates the inner chamber and the outer chamber, and both width ends thereof are substantially formed in the respective bead portions. A safety tire that is inserted into an annular groove extending along a tire circumferential direction and fixed to the bead portion by fitting a ring-shaped fixing member into the annular groove.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, although the structure is relatively simple and lightweight, there is little risk of the diaphragm coming into contact with the inner surface of the tire when traveling under normal internal pressure, and therefore there is little risk of damage. Furthermore, since air can be supplied from the inner chamber to the outer chamber via the communication portion, it can be mounted on a conventional rim. In addition, since the diaphragm is fixed to the bead portion of the tire, there is no possibility that the diaphragm is detached from the tire when the rim is assembled and used.

  The “substantially tire circumferential direction” here means that it includes a slight inclination that inevitably occurs in production, and more specifically, the angle formed with the tire circumferential direction is ± It means a direction within a range of 5 °.

  The annular groove may be formed on the inner peripheral surface of the bead portion, that is, the surface facing the space defined by the tire and the rim when the tire is mounted on the rim, or formed on the bead base of the bead portion. Also good.

  The annular groove preferably has an opening width smaller than the maximum width of the fixing member.

  Furthermore, it is preferable that both width end portions of the diaphragm extend beyond the annular groove and are held between the bead portion and the rim when the rim is mounted.

Furthermore, as the communication portion, while the inner chamber and the outer chamber communicate with each other, when the internal pressure of the tire suddenly decreases due to puncture or the like, the flow rate of the air passing therethrough is limited, and the inner chamber and the outer chamber are limited. Although it will not specifically limit if a differential pressure is produced between, From a viewpoint of weight reduction, it shall be a small hole which penetrates a diaphragm, or it is comprised by the opening which penetrates a diaphragm, and the filter member which covers this Is preferred. When a small hole is used as the communicating portion, the diameter is preferably in the range of 0.5 to 5 mm. Moreover, when using a filter member for a communication part, it is preferable to use a nonwoven fabric, and as this nonwoven fabric, it is especially preferable that a fabric weight is in the range of 5-1000 g / m < ² >.

  Instead of these, the communication part may be a valve member that opens and closes due to a differential pressure between the inner chamber and the outer chamber. Examples of usable valve members include check valves and relief valves.

  Further, the communication portion 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 ˜110%. By adjusting the differential pressure in this way, it is possible to prevent the diaphragm from coming into contact with the rim and the tire inner surface in a normal internal pressure state in which the internal pressure of the tire is maintained within an appropriate range, and quickly when the internal pressure in the outer chamber is reduced. The air in the inner chamber can be expanded.

  In addition, when the tire is in the normal internal pressure state, the diaphragm does not contact the inner surface of the tread portion while defining the inner chamber and the outer chamber, and on the other hand, when the tire is in a run flat state in which the tire internal pressure is reduced, The material, physical properties, shape and the like are not particularly limited as long as they can support the load applied to the tire by expanding and deforming, but from the viewpoint of preventing the diaphragm from being damaged in the run-flat state, the elongation at break is 50. % Or more is preferable.

  According to the present invention, the load is supported when the internal pressure is reduced with a simple structure as compared with the conventional safety tire, so that the weight can be reduced and the mounting to the conventional rim is easy. Therefore, versatility and rim assembly are 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 and rim assembly formed by mounting a representative safety tire (hereinafter referred to as “tire”) according to the present invention on a rim, in a state before and after applying internal pressure. FIG. 2 shows a state in which the internal pressure of the tire shown in FIG. 1 has decreased and run-flat running has been achieved, and FIG. 3 shows an enlarged cross section of the bead portion of the tire shown in FIGS. Yes.

  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 extending between the pair of bead portions 3 is disposed in the tire 1 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 communication portion 10 that allows the inner chamber 8 and the outer chamber 9 to communicate with each other while restricting the flow rate. The diaphragm 6 is made of an air-impermeable and extensible material such as rubber, a composite of rubber and nonwoven fabric, and a thermoplastic resin (generally called TPE) such as TPO (olefinic thermoplastic elastomer). In particular, TPO is used in consideration of elongation (breaking elongation) and weight reduction of the diaphragm 6 when the internal pressure of the outer chamber 9 is reduced, normal holding of the diaphragm during normal running, and suppression of creep due to centrifugal force. It is preferable. Moreover, it is preferable that the thickness of the diaphragm 6 exists in the range of 0.3-5.0 mm. The reason is that if the thickness is less than 0.3 mm, the diaphragm 6 may interfere with foreign matter when contacting the tire inner surface, and the diaphragm may be damaged. If the thickness exceeds 5 mm, the tire This is because, as a result of the increase in the mass of the tire, there is a possibility that the tire performance such as the generation of creep due to centrifugal force and the fuel efficiency may be impaired.

  As shown in an enlarged view in FIG. 3, each bead portion 3 is formed with an annular groove 11 extending substantially along the tire circumferential direction. Has been inserted. Further, a ring-shaped fixing member 12 is also inserted and fitted into the annular groove 11, thereby fixing the diaphragm 6 to the bead portion 3.

  When air is supplied to the inner chamber 8 via the air filling valve 13 provided on the rim 7, a part of the supplied air is supplied to the outer chamber 9 via the communication 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 communication unit 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 safety tire can be constructed simply by adding a lightweight diaphragm 6 having a simple structure, so that a metallic core is arranged in the tire or a sealant agent is filled in the inner space of the tire. Significant weight reduction can be achieved compared to conventional safety tires. Further, since the diaphragm 6 is fixed to the bead portion 3, the diaphragm 6 is not displaced when the tire is assembled to the rim, so that the rim assembly property is improved and the diaphragm is not likely to come off from the tire during use. .

  As shown in FIG. 3, the annular groove 11 may be provided on the inner peripheral surface of the bead portion 3 on the outer side in the tire radial direction of the bead core 2, but as shown in FIG. You may provide in the direction inner side. Alternatively, as shown in FIG. 4B, the annular groove 11 may be formed in the bead base of the bead portion 3. According to this, since the fixing member 12 is pressed by the bead portion 3 and the rim 7, the fixing member 12 does not come out of the annular groove 11 even if a tension acting on the diaphragm 6 is applied, and the safety tire. As reliability improves.

  The cross-sectional shape of the annular groove 11 can be a circle, an ellipse, a triangle, a rectangle, etc., but from the viewpoint of holding the fixing member 12 accommodated therein, the opening width should be smaller than the maximum width of the fixing member. As shown in FIGS. 3 and 4, it is particularly preferable to use a so-called flask shape composed of a narrowed portion extending from the opening and a circular enlarged portion extending from the opening to the bottom.

  The cross-sectional shape of the fixing member 12 can be a circle, an ellipse, a triangle, a rectangle, or the like. Instead of these, as the fixing member 12, as shown in FIG. 5, a thin plate processed into a U shape may be used. The material of the fixing member can be hard rubber, resin, metal, or the like.

  For example, as an annular groove, a flask-shaped groove having an opening width of 1.5 mm, a length of the constriction portion of 1.5 mm, and a circular enlarged portion having a diameter of 3.0 mm is formed. A fixing member obtained by bending a 0.0 mm steel wire into a ring shape, or a steel plate having a thickness of 0.5 mm, is bent into a U shape as shown in FIG. 5 so that the bottom becomes an arc shape with R = 2.0 mm. The fixed member thus made can be fitted.

  Further, as shown in FIGS. 4C to 4E, both width end portions of the diaphragm 6 can be extended from the annular groove 11 and can be held between the bead portion 3 and the rim 7 when the rim is mounted. According to this, in addition to the fixing action by the annular groove 11 and the fixing member 12, the fixing action by holding the bead portion 3 and the rim 7 is also obtained, so that the diaphragm 6 can be fixed more reliably.

  In the embodiment shown in FIG. 1, the communicating portion 10 is formed by opening a small hole penetrating the material constituting the diaphragm 6. According to this, since an additional member is not required, the structure is simple and the weight can be further reduced, and the difference in mass between the portion provided with the small hole and the portion not provided is small, and the tire uniformity is reduced. There is no loss. 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. When the inner pressure of the inner chamber decreases, the air in the inner chamber and the air in the outer chamber also flow out of the tire, and the differential pressure between the outer chamber 9 and the inner chamber 8 becomes insufficient, and the run flat function may not be secured. It is.

FIG. 6 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. In this embodiment, the communicating portion 10 is configured by opening an opening penetrating the material constituting the diaphragm 6 and covering the opening with a filter member having a large number of pores. According to this, since a relatively lightweight filter member is used, the structure is relatively simple and relatively lightweight, and the difference in mass between the portion where the filter member is provided and the portion where the filter member is not provided is relatively small. There is little, and there is little damage to tire uniformity. 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. And this differential pressure | voltage can be adjusted by selecting suitably the diameter or number of the pores of a filter member. A suitable filter member is a nonwoven fabric. Since the nonwoven fabric is a porous sheet in which fibers are overlapped and bonded in a three-dimensional structure, a high differential pressure can be generated between the inner chamber and the outer chamber as compared with the communication portion constituted by small holes. 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. When a non-woven fabric with 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 13, the difference between the inner chamber 8 and the outer chamber 9 is temporarily increased. 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. 7 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. In this embodiment, the communicating portion 10 is configured by opening an opening penetrating the material constituting the diaphragm 6 and disposing a valve member in the opening. According to this, the differential pressure between the inner chamber and the outer chamber can be controlled more reliably. Such a valve member is not particularly limited as long as it opens and closes according to the differential pressure between the inner chamber and the outer chamber, and for example, a check valve or a relief valve can be used.

  In the illustrated embodiment, the communication portion 10 is provided on the substantially equatorial plane of the tire. However, the arrangement position is not limited to this, and for example, the communication portion 10 may be arranged to face the sidewall portion 4. . Moreover, the magnitude | size and the number of the communication parts 10 can be increased / decreased suitably according to a tire size, the internal pressure at the time of use, etc.

  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 110% or less of the internal pressure of the outer chamber 9.

  Moreover, it is preferable that the diaphragm 6 has the physical property which expands rapidly to a tire inner surface at the time of internal pressure fall. Specifically, the elongation at break is preferably 50% or more.

  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 apparent from the above description, according to the present invention, the load is supported when the internal pressure is reduced with a simple structure as compared with the conventional safety tire, so that it is lightweight and can be easily mounted on the conventional rim. It has become possible to provide a highly versatile safety tire.

It is sectional drawing in the tire width direction of the tire and rim assembly comprised by mounting | wearing the rim with the typical safety tire according to this invention, and shows the state before and after applying an internal pressure. FIG. 2 is a cross-sectional view in the tire width direction of the safety tire shown in FIG. 1 in a run flat running state in which the internal pressure is reduced. It is an expanded sectional view of the bead part of the safety tire shown in FIG. (A)-(e) is an expanded sectional view of the bead part of the various safety tire according to this invention. It is sectional drawing of an example of a fixing member. These are sectional drawings 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. These are sectional drawings 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.

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 Communication part 11 Annular groove 12 Fixing member 13 Air filling valve

Claims (10)

In a safety tire having a pair of bead portions, a pair of sidewall portions extending outward in the tire radial direction from the bead portion, and a tread portion extending between both sidewall portions,
The safety tire extends between the bead portions, and when the tire is mounted on a rim, the space defined between the tire and the rim is divided into two chambers on the inner side and the outer side in the tire radial direction. With an additional annular diaphragm,
The diaphragm includes at least one communicating portion that communicates the inner chamber and the outer chamber, and an annular groove formed at each bead portion and extending substantially along the tire circumferential direction. A safety tire characterized by being inserted into the ring and being fixed to the bead portion by fitting a ring-shaped fixing member into the annular groove.   The safety tire according to claim 1, wherein the annular groove is formed on an inner peripheral surface of the bead portion.   The safety tire according to claim 1, wherein the annular groove is formed in a bead base of the bead portion.   The safety tire according to any one of claims 1 to 3, wherein the annular groove has an opening width smaller than a maximum width of the fixing member.   The safety tire according to any one of claims 1 to 4, wherein both end portions of the diaphragm extend beyond the annular groove and are clamped between the bead portion and the rim when the rim is mounted.   The safety tire according to any one of claims 1 to 5, wherein the communication portion is a small hole that penetrates the diaphragm.   The safety tire according to any one of claims 1 to 5, wherein the communication portion includes an opening that penetrates the diaphragm and a filter member that covers the opening.   The safety tire according to any one of claims 1 to 5, wherein the communication portion is a valve member that opens and closes due to a differential pressure between the inner chamber and the outer chamber.   The said communication part adjusts the internal pressure of the said inner side chamber more than the internal pressure of the said outer side chamber in the state which mounted | wore the tire with the rim | limb and was filled with predetermined | prescribed internal pressure. Safety tire.   The safety tire according to any one of claims 1 to 9, wherein the diaphragm has an elongation at break of 50% or more.

Images