JP2007022412A - Bladder for safety tire and safety tire - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a bladder for a safety tire improving durability by preventing biased expansion in run-flat travelling by optimizing tensile strength distribution of a reinforcing layer and the safety tire having such the bladder. <P>SOLUTION: This hollow tubular bladder 1 for the safety tire is stored in a tire 2 and constitutes the safety tire. This bladder 1 is furnished with a gas impermeable layer 3 and a reinforcing layer 4 arranged on an outer surface of the gas impermeable layer 3 and to burden tensile force applied on the bladder. The reinforcing layer 4 is constituted of a crown center part 5, a pair of crown shoulder parts 6, 6, a pair of side parts 7, 7, a pair of bead parts 8, 8 to pressurize the bladder on a rim and a base part 9. Tensile strength of the bead part 8 is made more than 0.8 time of tensile strength of the crown shoulder part 6 and the bead part 8 is made a fixing point of the bladder 1. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention is for a hollow tubular safety tire comprising a gas impermeable layer that maintains the internal pressure of air bladder and a reinforcing layer that is disposed on the outer surface of the gas impermeable layer and bears the tension applied to the air bladder. The present invention relates to air bladders, and in particular, aims to improve the durability of such air bladders.

  Reinforcing members such as a reinforcing tube, reinforcing rubber, and reinforcing belt, or a foam, elastic body, medium, and the like as a safety tire that can travel a certain distance even in a run-flat state in which the tire internal pressure has suddenly decreased due to puncture or the like There are known tires that support the load of the tire on the shoulder, tires that are coated or filled with a sealant agent, block damaged parts such as holes formed in the tire, and prevent a decrease in internal pressure, and the like. However, these conventional safety tires have a complicated manufacturing method, and there are many cases where there are difficulties in handling at the time of wearing.

  In order to solve such a problem, for example, in Patent Documents 1 and 2, in a run-flat state where the internal pressure of the tire is reduced and the internal pressure of the tire is reduced, the load is supported by being expanded and deformed as the tire internal pressure is reduced. A hollow circular air bladder that replaces the shoulder of a tire and a safety tire using the same are described.

JP 2003-136923 A JP 2003-159914 A

  In the tires described in Patent Documents 1 and 2, the internal pressure of the air bladder is set higher than the internal pressure of the tire, and the air bladder is brought into close contact with the rim and fixed by this differential pressure. However, the internal pressure of the air bladder and the internal pressure of the tire fluctuate with the temperature change, and since air leaks naturally from the tire, it is difficult to keep this differential pressure constant. If the differential pressure between the internal pressure of the air bladder and the tire is reduced due to air leaks, the force to fix the air bladder to the rim is insufficient with respect to the centrifugal force generated by the tire rolling. Uncertain. On the other hand, if the initial differential pressure between the air bladder internal pressure and the tire internal pressure is increased in anticipation of air leakage, the air bladder may be expanded and deformed even when the tire internal pressure is normal. As described above, it has been difficult to stably fix the air bladder of Patent Documents 1 and 2 depending on the differential pressure between the internal pressure of the air bladder and the internal pressure of the tire to the rim. Insufficient fixing to the rim of the air bag will damage the uniform expansion deformation when the internal pressure drops, and it is easy to cause partial expansion. In some cases, the desired run-flat durability cannot be obtained due to the low strength of the steel.

  The object of the present invention is to solve such problems of the prior art, and its purpose is to achieve uneven expansion during run-flat travel by optimizing the tensile strength distribution of the reinforcing layer. An object of the present invention is to provide a safety tire air bladder and a safety tire having such an air bladder which are improved in durability.

  In order to achieve the above object, the air bladder for a safety tire according to the present invention comprises a gas impermeable layer that maintains the internal pressure of the air bladder and a tension applied to the air bladder that is disposed on the outer surface of the gas impermeable layer. In a hollow tubular safety tire air bladder having a reinforcing layer that bears the load, the air bladder is stored in a tire, assembled to a standard rim, and at an internal pressure set in relation to a predetermined internal pressure of the tire. In the cross section in the width direction in a state filled with gas, the reinforcing layer includes a crown center portion facing the inner surface of the tire tread center region, and inner surfaces of the tire tread shoulder region located on both sides of the crown center portion. A pair of crown shoulder portions opposed to each other, a pair of side portions extending radially inward of the crown shoulder portion and extending opposite to an inner surface of the sidewall portion of the tire, and the side portions being rims The bead comprises a pair of bead portions extending along the rim from the touching point toward the inner side in the width direction and pressing the air bladder against the rim, and a base portion extending between the bead portions and facing the rim. The tensile strength of the portion is 0.8 times or more the tensile strength of the crown shoulder portion. According to this, when the air bag expands and deforms due to a decrease in the tire internal pressure, the bead portion of the reinforcing layer becomes a fixed point, so that partial expansion can be suppressed.

  Here, “standard rim” is defined by industrial standards and standards that are effective in the area where tires are manufactured, sold, or used, such as JATMA, TRA, ETRTO, etc., for safety tires that store pneumatic bladders. The standard rim (or “Approved Rim”, “Recommended Rim”) at the applied size. Further, the “predetermined internal pressure of the tire” refers to an internal pressure that is specified in accordance with the above-mentioned industrial standards, standards, etc. and specified according to the load capacity with respect to the safety tire that stores the air bladder. Further, “internal pressure set in relation to a predetermined internal pressure” means that a space is formed between the outer surface of the air bladder and the inner surface of the tire in a gas-filled state in which the predetermined internal pressure is applied to the tire. On the other hand, in the run-flat state where the internal pressure of the tire is reduced, the air pressure is expanded and deformed as the tire internal pressure is reduced, and the internal pressure can be used to replace the load support from the tire. The internal pressure is in the range of +0 to 20%. “Tensile strength” is the tensile strength when the length of a non-stretched sample is 100 and a force is applied in the circumferential direction to cause 10% elongation, that is, the sample length is 110. It shall be said.

  In the reinforcing layer constituting the air bladder, the tensile strength of the side portion is 0.02 to 0.4 times the tensile strength of the crown shoulder portion, and the tensile strength of the crown center portion is the crown shoulder portion. The tensile strength of the base shoulder is 0.5 times or more and 0.85 times or less, the tensile strength of the base portion is 0.02 times or more and 0.8 times or less, and the tensile strength of the crown shoulder portion. The strength is preferably 441 N / cm or more and 1177 N / cm or less, respectively.

  Furthermore, at least a part of the reinforcing layer is preferably composed of a resin or a nonwoven fabric. In the latter case, an aramid nonwoven fabric or a polyethylene terephthalate nonwoven fabric is particularly preferable. In addition to or together with this, it is preferable that at least a part of the reinforcing layer is formed by rubber-covering a polyethylene terephthalate fiber cord.

In addition, in the cross-section in the width direction of the air bladder, the total peripheral length of the reinforcing layer is L ₁ , the peripheral length of the crown center portion is L ₂ , the peripheral length of the crown shoulder portion is L ₃ , and the peripheral portion of the side portion is When the length is L ₄ and the peripheral length of the bead portion is L ₅ , it is preferable that L _{1 to} L ₅ satisfy the following relationship.
0.3 ≦ L ₄ / (L ₂ + L ₃ ) ≦ 0.9
0.05 ≦ L ₃ / (L ₂ + L ₃ ) ≦ 0.4
0.05 ≦ L ₅ / (L ₂ + L ₃ ) ≦ 0.2
0.25 ≦ (L ₂ + L ₃ ) / L ₁ ≦ 0.48
In addition, these peripheral lengths shall be measured in the said gas filling state.

  And the safety tire of this invention has one of the above-mentioned air bladders.

  According to the present invention, by optimizing the tensile strength distribution of the reinforcing layer, it exhibits good fixability without being affected by the differential pressure between the internal pressure of the air bladder and the internal pressure of the tire. It is possible to provide an air bladder for a safety tire that prevents uneven expansion during traveling and has improved durability, and a safety tire having such an air bladder.

  Next, embodiments of the present invention will be described with reference to the drawings. FIG. 1 shows a cross-section in the width direction of a typical safety tire pneumatic bladder (hereinafter referred to as “air bladder”) according to the present invention.

The air bladder 1 shown in FIG. 1 has a hollow circular tube shape and is housed in a tire 2 to form a safety tire. The safety tire is mounted on the rim R to form a tire assembly. The tire 2 is filled with a predetermined air pressure via an air filling valve (not shown), and the air bladder 1 is filled with a predetermined air pressure of the tire 2 via another air filling valve (not shown). As a result, as shown in FIG. 1, a space S ₁ is formed in the tire 2 and a space S ₂ is formed in the air bladder 1. On the other hand, when the internal pressure of the space S ₁ of the tire 2 is suddenly reduced by puncture or the like, the internal pressure difference between the space S ₁ and the space S ₂ becomes large. As a result, the air bladder 1 is expanded and deformed, and finally the tire 2. The inner surface of the tire 2 is reached and the load is supported from the tire 2 by shoulder. The air bladder 1 includes a gas impermeable layer 3 that maintains the internal pressure of the air bladder 1 and a reinforcing layer 4 that is disposed on the outer surface of the gas impermeable layer 3 and bears the tension applied to the air bladder 1. It has.

  The main feature of the present invention is that the reinforcing layer 4 is stored in the tire 2 as shown in the drawing, assembled to the rim, and applied with a predetermined internal pressure. The crown center portion 5 facing the rim, a pair of crown shoulder portions 6 and 6 located on both sides of the crown center portion 5 and facing the inner surface of the shoulder region of the tread portion of the tire 2, and the radial direction of the crown shoulder portions 6 and 6 A pair of side portions 7, 7 extending inward and facing the inner surface of the sidewall portion of the tire 2, and extending along the rim R inward in the width direction from the point where the side portions 7, 7 make R contact with the rim. , Comprising a pair of bead portions 8 and 8 for pressing the air bladder 1 against the rim R, and a base portion 9 extending between the bead portions 8 and 8 so as to face the rim R, and tensioning the bead portions 8 and 8 Powerful crow It is to a tensile strength of 0.8 times or more of the shoulder portions 6.

  In the conventional air bladder, in order to provide sufficient load support even after expansion deformation, the internal pressure of the air bladder is made 0 to 20% higher than the tire internal pressure when the tire internal pressure is normal. In order to prevent the expansion of the air bag due to the internal pressure difference, a reinforcing layer is provided to bear the tension. In particular, since the cross-sectional shape of the air bladder is flat and the ratio of the tension borne by the crown portion increases, in order to maintain the cross-sectional shape of the air bladder under normal tire internal pressure, a reinforcing layer for the crown portion is required. It is necessary to reinforce the tensile strength of the crown portion by increasing the thickness or by disposing a high strength member on the outer periphery of the crown portion. On the other hand, the portion of the air bag that contacts the rim is pressed against the rim before and after the expansion of the air bag, so that there is little dimensional change and tension load. For this reason, from the viewpoint of weight reduction, no reinforcing layer is disposed at the portion that contacts the rim, or a very thin reinforcing layer is disposed as compared with the crown portion. Such a conventional safety tire air bladder is relatively loosely fixed to the rim mainly by the action of the air pressure filled inside, so that the tires are affected by the lateral G generated during cornering and the vibration from the road surface. In some cases, it is biased to the left or right. In such a state where the air bladder is biased, the distance between one half of the air bladder and the tire inner surface is smaller than the distance between the other half and the tire inner surface, so that the internal pressure of the tire is reduced. Then, the expansion of one half is small and the expansion of the other half is large. For this reason, in the half of the expansion, the thickness becomes thin, and it tends to break during run flat running, or in extreme cases, it breaks at the diameter expansion deformation stage before run flat running. There is a case. In order to prevent such blistering, it is necessary to fix the air bladder at a predetermined position even when affected by external force.

  Therefore, in the air bladder 1 of the present invention, the tensile strength of both width end portions of the portion in contact with the rim R, that is, the portion extending inward in the width direction from the point where the shoulder portion 7 contacts with the rim R is determined. The bead portion 8 is made higher than the above, and when pressure is applied to the inside, it is firmly pressed and fixed to the rim. As a result, even when the lateral G generated during cornering or the vibration from the road surface is applied, the air bladder can be stably fixed to the rim, and the blister can be effectively prevented.

  Here, the arrangement position of the bead portion 8 is defined as the boundary position between the portion that contacts the rim R and the side portion 7 when there is a portion that contacts the rim R on the outer side in the width direction of the bead portion 8. Since it is loosely fixed to the rim, there is a risk of being biased to the left or right within the tire due to the influence of external force, but eliminating such a risk completely eliminates the possibility of bias Because it can. In addition, if the tensile strength of the bead portion 8 is too low, the bead portion 8 cannot sufficiently serve as a fixing point for the air bladder 1, and if a large external force is applied, the bead portion 8 may be biased. The tensile strength of must be at least 0.8 times the tensile strength of the crown shoulder portion 6. The higher the tensile strength of the bead portion 8 is, the higher the fixing effect is, but at the same time the cost is increased, so it is preferable that the tensile strength of the shoulder portion 6 is 20 times or less.

  If the tensile strength of the side portion 7 is too low compared to the tensile strength of the crown shoulder portion 6, as a result of starting expansion deformation from the side portion 7 when the tire internal pressure decreases, a so-called back which is a kind of one-sided swelling as shown in FIG. Ring deformation may occur, and there is a concern about a decrease in durability of the air bladder. From the viewpoint of preventing such buckling deformation, the tensile strength of the side portion 7 is preferably at least 0.02 times the tensile strength of the crown shoulder portion 6. However, even if the tensile strength of the side portion 7 is too large, the side portion 7 cannot reach the inner surface of the tire 2 when the tire internal pressure is lowered, and the shoulder cannot be supported with a sufficient load by air bladder. There is a concern that the durability of the amber will decline. Therefore, from the viewpoint of sufficiently expanding the side portion 7, the tensile strength is preferably 0.4 times or less than the tensile strength of the crown shoulder portion 6.

  Further, in order to prevent such buckling deformation, the crown center portion 5 of the air bag may be rapidly expanded and deformed. That is, if the tensile strength of the crown center portion 5 is reduced, buckling deformation as shown in FIG. 3 can be prevented if the crown center portion 5 expands and deforms simultaneously with the side portion 7 when the tire internal pressure decreases. Even with this configuration, if the tensile strength of the crown shoulder portion 6 is kept high, it is possible to maintain the cross-sectional shape of the air bladder when the tire internal pressure is normal. Then, when research was repeated about the appropriate range of the tensile strength of the crown center part 5, it turned out that 0.85 times or less of the tensile strength of the crown shoulder part 6 is preferable. However, if the difference in tensile strength between the crown center portion 5 and the crown shoulder portion 6 becomes too large, the rigidity step between the two portions becomes too large, and stress may concentrate on the boundary between the two portions at the time of expansion deformation, which may cause breakage. I also found that there is. From the viewpoint of preventing such breakage, it is preferable that the tensile strength of the crown center portion 5 is 0.5 times or more the tensile strength of the crown shoulder portion 6.

Conventionally, a sac hollow circular tube air guides the gas filled in the space S ₁ in the rim R, in order to dissipate Here, as shown in FIG. 2, the irregularities formed on the outer surface of the base portion 9, the gas Securing the flow passage 10 is performed. If the rigidity of the base portion 9 is too low, the flow passage 10 may be crushed and the heat dissipation effect from the rim R may be impaired. Therefore, it is preferable that the tensile strength of the base portion 9 is 0.02 times or more the tensile strength of the crown shoulder portion 6 to ensure the rigidity of the base portion 9. However, the rigidity of the base portion 9 is too high, be filled with gas in the internal space S ₂ of the air bladder 1, base portion 9 does not contact the rim, vibration is a concern that occur during travel Therefore, it is preferable that the tensile strength of the base portion 9 is 0.8 times or less of the crown shoulder portion 6 and the base portion 9 is brought into close contact with the rim R by the action of internal pressure.

As described above, the internal pressure of the air bladder 1 is set higher than the internal pressure of the tire 2, and the crown shoulder portions 6 and 6 mainly bear the tension generated by this differential pressure, so that the air pressure is normal when the tire internal pressure is normal. A space S ₁ between the tire 1 and the tire 2 is maintained. From the viewpoint of sufficiently bearing such tension and maintaining the cross-sectional shape of the air bladder 1 to be flat, it is preferable that the tensile strength of the crown shoulder portion 6 is at least 441 N / cm. However, if the tensile strength is too large, the expansion speed when the tire internal pressure is lowered becomes too slow, which may be another factor of buckling deformation. Therefore, it is preferable to set the tensile strength to 1177 N / cm or less.

  Moreover, it is preferable that at least a part of the reinforcing layer 4 is made of resin. In general, a resin behaves as a high-rigidity material with a low elongation rate in a low tension region, but when a certain tension (yield strength) is exceeded, the elongation rate increases rapidly and the yield strength is adjusted by adjusting the thickness. Can be adjusted relatively easily. Therefore, if the reinforcing layer 4 is made of resin, desired characteristics can be obtained relatively easily.

  As described above, the reinforcing layer 4 serves to maintain the cross-sectional shape of the air bladder in a state where the tire internal pressure is normal and to maintain the cross-sectional shape of the air bladder. It is desirable not to disturb the function of expanding and deforming. From this viewpoint, it is preferable that at least a part of the reinforcing layer 4 is made of a nonwoven fabric. This is because, when a force exceeding a certain limit is applied to the nonwoven fabric, the fibers are entangled with each other and plastically deformed, so that the diameter expansion deformation of the tube is not hindered. The nonwoven fabric is preferably composed of a resin, particularly aramid fiber or polyethylene terephthalate (PET) fiber. This is because such a fiber material has high strength, so that the rigidity reinforcing effect is enhanced and the elastic deformation is possible to some extent, and therefore, the expansion during the diameter expansion deformation becomes smoother.

  Further, at least a part of the reinforcing layer 4 may be a composite formed by rubber-covering a polyethylene terephthalate fiber cord. Such a composite can be used for any part of the crown center part 5, the crown shoulder part 6, the side part 7, the bead part 8 and the base part 9 of the reinforcing layer 4, but the tensile strength of the composite is high. Therefore, it is particularly suitable for use in the crown shoulder portion 6 and the bead portion 8.

In addition to such a configuration, since the cross-sectional shape of the air bladder 1 has a great influence on durability, it is preferable to optimize it. Specifically, if the side portions 7 and 7 are too small compared to the crown portion (the portion composed of both the crown shoulder portions 6 and 6 and the crown center portion 5), the ratio at which the side portions 7 and 7 should expand during expansion deformation. May become too large, and the reinforcing layer 4 may be broken. From the viewpoint of preventing such breakage, the total length L ₄ of the peripheral lengths of both side portions 7, 7 is the peripheral length of the crown portion, that is, the peripheral length L ₂ of the crown center portion 5 and the crown shoulder portions 6, 6. The sum of the peripheral lengths L ₃ and the sum L ₂ + L ₃ is preferably at least 0.3 times. However, if L ₄ becomes too large, the width of the crown portion becomes relatively narrow, and it becomes difficult to keep the air bladder in a flat cross-sectional shape when the tire internal pressure is normal, so L _{4 is set} to 0 of L ₂ + L ₃ . .9 times or less is preferable.

Further, if the ratio of the crown center portion 5 occupying the crown portion is too small, the effect of preventing buckling deformation may not be sufficiently obtained by providing the crown center portion 5 having a low tensile strength. That is, L ₃ / (L ₂ + L ₃ ) is preferably at least 0.05. However, if the ratio of the crown center portion 5 to the crown portion is too large, the crown shoulder portions 6 and 6 become relatively small and cannot bear the tension, and the cross-sectional shape of the air bladder is maintained flat. Therefore, it is preferable to set L ₃ / (L ₂ + L ₃ ) to 0.4 or less.

The bead portions 8 and 8 play a particularly important role in stably fixing the air bladder 1 to the rim R. From the viewpoint of securing the pressing force, the peripheral lengths of the bead portions 8 and 8 are both. it is preferably the sum _{L 5} of which at least 0.05 times the periphery length _L 2 + _{L 3} of the crown portion. However, if which L ₅ too large, the smaller the relative side portions 7, too large proportions to be extended side portions 7, 7 during expansion deformation, the reinforcing layer 4 is likely to break. From the viewpoint of preventing such breakage, L ₅ / (L ₂ + L ₃ ) is preferably 0.2 or less.

Further, in order to maintain the cross-sectional shape of the air bladder 1, a ratio (L ₂ + L ₃ ) / L _{1 in} which the length L ₂ + L ₃ of the crown portion occupies the front peripheral length L ₁ of the reinforcing layer is ensured. More specifically, (L ₂ + L ₃ ) / L ₁ is preferably 0.25 or more. However, if (L ₂ + L ₃ ) / L ₁ is too large, the side portions 7 and 7 are relatively small, and the proportion of the side portions 7 and 7 to be expanded at the time of expansion deformation is too large, and the reinforcing layer 4 is May break. From the viewpoint of preventing such breakage, (L ₂ + L ₃ ) / L ₁ is preferably set to 0.48 or less.

  When the air bladder thus formed is stored in a tire, the safety tire of the present invention is obtained. The type of tire that stores the air bladder is not particularly limited, and may be a radial tire or a bias tire.

  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. .

  Next, a safety tire pneumatic bladder according to the present invention was prototyped and performance evaluation was performed, which will be described below.

  The air bladders of Examples 1 to 4 are used by being housed in a safety tire having a tire size of 495 / 45R22.5, and have the structure shown in FIG. 1 and the specifications shown in Table 1. The crown center portion is made of a composite of an aramid nonwoven fabric and rubber and has a peripheral length of 30 mm. The crown shoulder portion is composed of a composite of an aramid non-woven fabric and rubber and has a peripheral length of 360 mm. The side part is made of a composite of an aramid non-woven fabric and rubber in Examples 1, 3, and 4, and is made of a composite of a PET non-woven fabric and rubber in Example 2, and the peripheral length is 150 mm. In Examples 1, 2 and 4, the bead portion is made of PET fiber covered with rubber. In Example 3, the bead portion is made of a composite of an aramid nonwoven fabric and rubber, and the peripheral length is 45 mm. The base part is made of a composite of aramid nonwoven fabric and rubber in Examples 1, 3 and 4, and is made of a composite of PET nonwoven fabric and rubber in Example 2, and the peripheral length is 230 mm.

  For comparison, similar to the air bladder of Examples 1 to 4, the tire size is 495 / 45R22.5 and used in a safety tire, and the gas-impermeable layer is the same as that of Examples 1 to 4. Yes, the peripheral length of each part of the crown center part, crown shoulder part, side part, bead part and base part of the reinforcing layer is the same as in Examples 1 to 4, and each part is composed of a composite of aramid nonwoven fabric and rubber However, the tensile strength of the bead portion was outside the scope of the present invention, and the air bladders of the conventional example and the comparative example having the specifications shown in Table 1 were also prototyped.

The conventional example, the comparative example and the air bladders of Examples 1 to 4 are accommodated in a tire having a tire size of 495 / 45R22.5, and mounted on a rim having a rim size of 17.00 × 22.5 to form a tire wheel. This was attached to a test vehicle. Next, the internal pressure of the tire containing the air bladder (space S ₁ ) is 900 kPa (relative pressure), the internal pressure of the air bladder (space S ₂ ) is 970 kPa (relative pressure), and the tire load is 56.88 kPa. While turning around the corner of 75R, the buttress part was blown up and the air bladder was rapidly expanded. This experiment was started from a low speed condition, gradually shifted to a high speed condition, an upper limit speed capable of uniform expansion deformation was determined, and durability was evaluated based on this speed. The evaluation results are shown in Table 1.

  In addition, all the evaluation results shown in Table 1 are shown as an index ratio when the evaluation result of the air bladder of the conventional example is set to 100, and the larger the numerical value, the better the performance.

  From the results shown in Table 1, it can be seen that the air bladders of Examples 1 to 4 have significantly improved durability compared to the air bladders of the conventional example and the comparative example.

  As is apparent from the above description, the present invention can prevent uneven expansion during run-flat running by optimizing the tensile strength distribution of the reinforcing layer, thereby improving the durability of the air bladder for safety tires. It is also possible to provide a safety tire having such an air bladder.

FIG. 3 is a cross-sectional view in the width direction showing a state in which a safety tire containing a representative bladder for a safety tire according to the present invention is mounted on a rim and filled with a predetermined internal pressure. It is a cross-sectional perspective view of the base part of the air bag for other safety tires according to this invention. It is sectional drawing of the width direction which shows the state which the conventional air bladder deform | transformed buckling.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Air bladder 2 Tire 3 Gas impermeable layer 4 Reinforcement layer 5 Crown center part 6 Crown shoulder part 7 Side part 8 Bead part 9 Base part 10 Flow path

Claims (12)

In a hollow circular safety tire air bladder comprising a gas impervious layer that retains the internal pressure of the air bladder and a reinforcing layer that is disposed on the outer surface of the gas impervious layer and bears the tension applied to the air bladder. ,
In the cross-section in the width direction of the state in which the air bladder is stored in a tire, assembled to a standard rim, and filled with gas at an internal pressure set in relation to a predetermined internal pressure of the tire,
The reinforcing layer includes a crown center portion facing the inner surface of the tread portion center region of the tire, a pair of crown shoulder portions positioned on both sides of the crown center portion and facing the inner surface of the tire tread portion shoulder region, and the crown A pair of side portions extending radially inward of the shoulder portion and extending toward the inner surface of the sidewall portion of the tire, and extending from the point where the side portions contact the rim toward the inner side in the width direction along the rim, the air It consists of a pair of bead portions that press the sleeve against the rim, and a base portion that extends between the bead portions and faces the rim,
An air bladder for a safety tire, wherein the tensile strength of the bead portion is 0.8 times or more the tensile strength of the crown shoulder portion.   The air bladder according to claim 1, wherein the tensile strength of the side portion is 0.02 to 0.4 times the tensile strength of the crown shoulder portion.   The air bladder according to claim 1 or 2, wherein the tensile strength of the crown center portion is 0.5 to 0.85 times the tensile strength of the crown shoulder portion.   The air bladder according to any one of claims 1 to 3, wherein the tensile strength of the base portion is 0.02 to 0.8 times the tensile strength of the crown shoulder portion.   The air bladder according to any one of claims 1 to 4, wherein a tensile strength of the crown shoulder portion is 441 N / cm or more and 1177 N / cm or less.   The air bladder according to any one of claims 1 to 5, wherein at least a part of the reinforcing layer is made of a resin.   The air bladder according to any one of claims 1 to 6, wherein at least a part of the reinforcing layer is made of a nonwoven fabric.   The air bladder according to claim 7, wherein the nonwoven fabric is an aramid nonwoven fabric.   The air bladder according to claim 7, wherein the nonwoven fabric is a polyethylene terephthalate nonwoven fabric.   The air bladder according to any one of claims 1 to 9, wherein at least a part of the reinforcing layer is configured by rubber-covering a polyethylene terephthalate fiber cord. In the cross section of the air bladder in the width direction, the total peripheral length of the reinforcing layer is L ₁ , the peripheral length of the crown center portion is L ₂ , the peripheral length of the crown shoulder portion is L ₃ , and the peripheral length of the side portion is L _4, when the periphery length of the bead portion was _{L 5,} satisfy L 1 ~L ₅ is the following relationship, air according to any one of claims 1 to 10.
0.3 ≦ L ₄ / (L ₂ + L ₃ ) ≦ 0.9
0.05 ≦ L ₃ / (L ₂ + L ₃ ) ≦ 0.4
0.05 ≦ L ₅ / (L ₂ + L ₃ ) ≦ 0.2
0.25 ≦ (L ₂ + L ₃ ) / L ₁ ≦ 0.48 The safety tire which has the air bladder for safety tires as described in any one of Claims 1-11.

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