JP5140311B2 - High load radial tire - Google Patents

Description

  The present invention relates to a high-load radial tire used for trucks, buses, industrial vehicles, construction vehicles, aircrafts and the like.

  Various studies have been made on the bead structure of a pneumatic radial tire in order to satisfy the motion performance and durability performance required for the tire. Also, with the development of highways and the speeding up of vehicles, tires are required to improve high-speed performance, and a higher load is applied between the rim and bead, so there is a need for a more durable rubber chafer. The nature is increasing.

  The performance required for the rubber chafer includes rim rubbing resistance, rim slip resistance, air sealability, air barrier property, sag resistance, and crack resistance. Since some of these requirements are in a trade-off relationship, one or two types of rubber materials have been selected in the past, and each of these required performances can be achieved moderately under mutual compromise. Constructed a rubber rubber chafer. However, in a tire provided with such a rubber chafer, rim rubbing, cracking, etc. are likely to occur relatively early in the portion that comes into contact with the rim flange from no load to 200% load, Also, the weather resistance is relatively low. Therefore, there has been a problem that these failures occurring in the tire impair the appearance of the tire and further cause a decrease in durability.

  Therefore, in aircraft radial tires that require high performance for rubber chafers, in order to increase the bending rigidity of the bead as much as possible, the elastic modulus when the second stiffener rubber is 100% stretched is the rubber chafer rubber. There are some which are larger than the elastic modulus at 100% elongation. However, in this case, since the second stiffener rubber is too hard, there is a possibility that the second stiffener rubber blows under traveling conditions that generate high heat. For this reason, different types of rubber are used for the second stiffener rubber during long-term running, and the elastic modulus at 100% elongation of the second stiffener rubber is set smaller than the elastic modulus at 100% elongation of the rubber chafer rubber. Patent Document 1 reports a radial tire for an aircraft in which failure of a bead portion such as rim displacement, blow, and peeling is prevented. However, further performance improvements of rubber chafers are necessary to meet market demands.

JP-A-7-172118

  Accordingly, the present invention provides a rubber chafer, particularly a portion that contacts the rim flange between no load and 200% of the normal load in a state where normal air pressure is filled, and rim rub resistance, crack resistance and weather resistance. An object of the present invention is to provide a high-load radial tire that greatly improves the performance and prevents the appearance and durability of the tire from being deteriorated.

As a result of intensive studies to achieve the above object, the present inventor, in a state in which normal air pressure is filled, in a portion that comes into contact with the rim flange during the time of loading with 200% of the normal load from no load, 24 ° C., frequency 52 Hz, Ri loss factor tanδ is der 0.2 in the vibration strain 2%, that at 100% elongation modulus M100 is disposed rubber chafer in the range of 5 to 7 (MPa) Thus, it has been found that the rim rubbing resistance, crack resistance and weather resistance can be greatly improved as compared with conventional products, and the appearance and durability of the tire can be prevented from being lowered, and the present invention has been completed.

That is, the radial tire for high load of the present invention is connected to the inner end in the tire radial direction of each sidewall portion extending inward in the tire radial direction from both ends of the tread portion, and the tire is properly connected to the bead portion seated on the rim. 24 ° C, frequency 52Hz, at least the part that comes in contact with the normal rim in the state where it is assembled to the rim and is in contact with the normal rim, and the part that comes into contact with the rim flange during no load to 200% normal load. Ri der loss factor tanδ is 0.2 or less in the vibration strain 2%, at 100% elongation modulus M100 is comprises a rubber chafer in the range of 5 to 7 (MPa).

Further, another high-load radial tire according to the present invention includes a tire connected to a tire radial inner end of each sidewall portion that extends inward in the tire radial direction from both ends of the tread portion. Is attached to the regular rim and filled with regular air pressure. From the part that contacts the rim flange to the part that contacts the rim flange from no load to 200% normal load, 24 ° C, frequency 52Hz , Ri loss factor tanδ is der 0.2 in the vibration strain 2%, at 100% elongation modulus M100 is comprises a rubber chafer in the range of 5 to 7 (MPa).

  Here, in a preferred example of the high-load radial tire of the present invention, the breaking strength of the rubber chafer is 10 (MPa) or more.

  Moreover, it is preferable that the high-load tire of the present invention is applied to an aircraft radial tire.

  The “regular rim” in the present invention refers to a standard rim (or “Applied Rim” or “Recommended Rim”) defined in the following standards. This standard is defined by an industrial standard effective in the region where tires are produced or used. For example, “The Tire and Rim Association Inc. YEAR BOOK” is used in the United States, and “The European Tire and Rim” is used in Europe. “Technical Organization Standards Manual”, and “JATMA YEAR BOOK” of Japan Automobile Tire Association in Japan.

  According to the present invention, the rim rub resistance, crack resistance, and weather resistance of the portion that contacts the rim flange between no load and 200% load in a state of being filled with a rubber chafer, particularly normal air pressure, can be obtained. It is possible to provide a high-load radial tire that is greatly improved as compared with conventional products and prevents the appearance and durability of the tire from being deteriorated.

  Hereinafter, the present invention will be described in detail with reference to the drawings. FIG. 1 is a partial cross-sectional view of a bead portion when no load is applied to a high-load radial tire of the present invention assembled to a regular rim, and FIG. 2 illustrates the present invention assembled to a regular rim. It is a fragmentary sectional view of a bead part at the time of 200% load of normal load in the state where normal air pressure of a high-load radial tire was filled.

  As shown in the drawing, the radial tire for high load of the present invention is seated on the regular rim 3 connected to the inner end in the tire radial direction of each sidewall portion 2 extending inward in the tire radial direction from both ends of the tread portion (not shown). A bead portion 1, and a carcass 5 that is folded and locked around the bead core 4 embedded in the bead portion 1 from the inside of the tire to the outside, and the tire is assembled to the regular rim 3 by the bead portion 1. At least a portion in contact with the regular rim 3 in a state in which the regular air pressure is filled (a portion 7A in contact with the rim flange 10 even when there is no load in the bead base portion 6 and the back surface of the bead) The loss coefficient tan δ at 24 ° C., a frequency of 52 Hz, and a vibration strain of 2% is 0.2 or less in the portion 7B that is in contact with the rim flange 10 during 200% load (FIG. 2). Comprising a certain rubber chafer 8 and 9.

  As described above, a low heat-generating rubber material having a loss factor tan δ of 0.2 or less at an amplitude distortion of 2% at 24 ° C. and a frequency of 52 Hz is located on the rubber chafer 8 and the bead base portion located on the bead back surface portion. When used for the rubber chafer 9, the pressure shear input generated between the rim and the rim during running can be reduced by reducing the frictional force, and the rim rub resistance, crack resistance and weather resistance of the tire can be greatly improved. It is possible to improve the durability while preventing the deterioration. Here, a rubber chafer with a loss coefficient tan δ exceeding 0.2 at an amplitude distortion of 2% at 24 ° C. and a frequency of 52 Hz is not sufficiently effective in reducing heat generation and reducing frictional force. Rubability, crack resistance and weather resistance are not improved. Further, the rubber chafers 8 and 9 are only required to be disposed at least in a portion in contact with the rim flange 10 and the rim base 11 (portion in contact with the rim flange of the bead base portion 6 and the bead back surface portion 7), and the shape is particularly limited. Not. In addition, although the bead core 4 and the carcass 5 are shown in FIGS. 1 and 2, these configurations are not particularly limited and can be appropriately selected. Further, the portion 7A in contact with the rim flange even when there is no load in the back surface of the bead shown in FIG. 1 and the portion 7B in contact with the rim flange between the time when there is no load and when the load is 200% of the normal load. This range is an example of the present invention. These ranges may vary depending on the shape of the tire and the like, but these changes are within the scope of the present invention.

  Further, another high-load radial tire of the present invention is seated on the regular rim 3 connected to the inner end in the tire radial direction of each sidewall portion 2 extending inward in the tire radial direction from both ends of the tread portion (not shown). A bead portion 1 and a carcass 5 that is folded and locked around the bead core 4 embedded in the bead portion 1 from the inside of the tire to the outside, and the tire is assembled to the regular rim 3 with the bead portion 1 From the portion 7A in contact with the rim flange 10 with air pressure filled, to the portion 7B in contact with the rim flange 10 during no load to 200% of the normal load, 24 ° C., frequency 52 Hz, vibration distortion A rubber chafer 8 having a loss coefficient tanδ at 2% of 0.2 or less is provided. Here, the rubber chafer 8 is only required to be disposed on at least a portion of the bead back surface 7 that is in contact with the rim flange 10, and the shape is not particularly limited. In addition, a rubber material having the same physical properties as the rubber chafer 8 positioned on the back surface of the bead may be used for the rubber chafer 9 positioned on the bead base portion of the tire, or a rubber material having different physical properties may be used. May be used.

  As described above, the bead base portion 6 is required by forming the rubber chafer 8 in contact with the rim flange 10 and the rubber chafer 9 in contact with the rim base 11 separately by using two kinds of rubber materials having different physical properties. The performance required for the bead back surface portion 7 can be designed separately. For example, in order to achieve only the performance required for the bead back surface portion 7 that contacts the rim flange 10 of the tire, a rubber material having predetermined physical properties may be disposed on the rubber chafer 8, and the rim base 11 may be contacted. The rubber chafer 9 is not particularly limited.

In a radial tire for heavy load according to the present invention, the modulus M100 at 100% elongation of the rubber chafer, Ri range near the 5 to 7 (MPa), be in the range of 5.5 to 6 (MPa) Is preferred. Here, when the modulus M100 at 100% elongation of the rubber chafer is less than 5 (MPa), the friction resistance of the rubber chafer is lowered, and when it exceeds 7 (MPa), the crack resistance is lowered.

  In the radial tire for high loads of the present invention, the breaking strength of the rubber chafer is preferably 10 (MPa) or more, and more preferably 15 (MPa) or more. When the breaking strength is less than 10 (MPa), the crack resistance of the rubber chafer is lowered.

  The rubber chafer having predetermined physical properties used in the high-load radial tire of the present invention can be produced by appropriately blending rubber components, fillers, resins, and the like well known to those skilled in the art. The radial tire for high load of the present invention can be manufactured using a rubber material satisfying the above physical properties for the rubber chafer 8 and, optionally, for the rubber chafer 9.

  The high-load radial tire of the present invention is not particularly limited, but is preferably used as a high-load radial tire applied to trucks, buses, industrial vehicles, construction vehicles, aircrafts, etc. Particularly preferred.

  EXAMPLES Hereinafter, the present invention will be described more specifically with reference to examples. However, the present invention is not limited to these examples, and can be appropriately changed without departing from the scope of the present invention.

  The rubber chafer having the composition shown in Table 1 is in contact with the rim flange 10 during the period from no load to 200% load with the appropriate air pressure filled from the contact portion between the tire and the rim (rubber chafer 8 And 9) to produce a radial tire for aircraft (size: 50 × 20.0R22 / 32PR) (conventional example 1, conventional example 2 and example 1). Further, in the portion that contacts the rim flange 10 from the time of no load to the time of 200% load in a state in which appropriate air pressure is filled from the contact portion between the tire and the rim, the portion that contacts the rim flange 10 (rubber chafer 8 ) And a portion (rubber chafer 9) in contact with the rim base. The rubber chafer 8 is provided with a rubber chafer having the physical properties shown in the table, and the rubber chafer 9 is similar to the conventional example 1. A rubber chafer was provided to produce an aircraft radial tire (size: 50 × 20.0R22 / 32PR) (Example 2). These radial aircraft tires have the same structure as the conventional radial aircraft tires except for the rubber chafer. After these radial tires for aircraft (Conventional Example 1, Conventional Example 2, Example 1 and Example 2) were assembled on a regular rim, a “rim back portion durability test” was performed. The value of tanδ in the table is a value measured with a spectrometer (manufactured by TOYOSEKI Co., Ltd.) under the conditions of room temperature, 52 Hz, and amplitude distortion of 2%. The values of M100 and breaking strength conform to JIS K6301. It is the value measured. The rim back surface durability test method is as follows.

(Rim back side durability test)
In the drum test, the tire was run at a speed of 64.5 km / h under a load of 120% of the specified load, and the time until the rubber chafer in contact with the rim was destroyed was measured. The test result is expressed as an index when the cumulative drum running time is defined as 100 for the test result of Conventional Example 1. The larger the value, the better the rim displacement resistance and crack durability.

* 1 JSR, BR01
* 2 Sumitomo Bakelite, Sumilite Resin PR50235
* 3 Nouchira H manufactured by Ouchi Shinsei Chemical Industry
* 4 N330
* 5 N220
* 6 Ouchi Shinsei Chemical Industry, Noxeller NS
* 7 N- (1,3-Dimethylbutyl) -N'-phenyl-p-phenylenediamine

  From the results shown in Table 1, both Examples 1 and 2 were superior in rim back surface durability compared to Conventional Examples 1 and 2. In particular, the second embodiment in which the rubber chafer 9 is provided with the same rubber chafer as in the conventional example 1 and the rubber chafer 8 is provided with the rubber chafer having the physical properties shown in the table is compared with the conventional example 1. Rim back surface durability such as rim slip friction and crack durability has been greatly improved, and the time to failure has more than doubled. In addition, when the air sealability, weather resistance, sag resistance, and rim slip resistance were also confirmed, Example 1 was superior to Conventional Example 1 in terms of these performances, and Example 2 was almost the same as Conventional Example 1. It was a level.

FIG. 1 is a partial cross-sectional view of a bead portion when there is no load in a state in which normal air pressure is filled in a high-load radial tire of the present invention assembled to a normal rim. FIG. 2 is a partial cross-sectional view of the bead portion when the normal load of the radial tire for high load of the present invention assembled to the normal rim is filled with a normal load of 200%.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Bead part 2 Side wall part 3 Regular rim 4 Bead core 5 Carcass 6 Bead base part 7 Bead back part 7A The part which contacts the rim flange 10 at the time of no load in the state filled with regular air pressure in the bead back part 7B Of the parts, the parts 8 and 9 that contact the rim flange 10 from when no load is loaded with normal air pressure to 200% of the normal load, rubber chafer 10 rim flange 11 rim base

Claims (4)

At the bead portion that is connected to the tire radial inner end of each sidewall portion that extends inward in the tire radial direction from both ends of the tread portion, and that the tire is assembled to the regular rim and filled with the regular air pressure at least From the portion in contact with the normal rim to the portion in contact with the rim flange from the time of no load to the load of 200% of the normal load, the loss coefficient tan δ at 24 ° C., frequency 52 Hz, vibration strain 2% is 0.2. hereinafter der is, a radial tire for heavy load, characterized in that it comprises a rubber chafer in at 100% elongation modulus M100 is in the range of 5 to 7 (MPa). In the state where the tire is assembled to the regular rim and filled with regular air pressure at the bead portion that is connected to the tire radial inner end of each sidewall portion extending inward in the tire radial direction from both ends of the tread portion, The loss coefficient tanδ at 24 ° C, frequency 52Hz, and vibration distortion 2% is 0.2 or less from the portion that contacts the rim flange to the portion that contacts the rim flange from no load to 200% of normal load. der is, a radial tire for heavy load, characterized in that it comprises a rubber chafer in at 100% elongation modulus M100 is in the range of 5 to 7 (MPa).   The radial tire for high loads according to claim 1 or 2, wherein the breaking strength of the rubber chafer is 10 (MPa) or more. The high-load radial tire according to any one of claims 1 to 3 , wherein the radial tire is an aircraft radial tire.

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