JP2008273077A - Bladder for tire vulcanization, and tire vulcanization method - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a bladder for tire vulcanization and a tire vulcanization method that prevent part of rubber of an unvulcanized tire from entering between sectors of a mold when pressurizing the inner face of the unvaulcanized tire. <P>SOLUTION: Each part in a bladder 33 corresponding to the dividing position of individual sectors 23a of a mold 20 is formed of a partial thick part 33a having a larger thickness in a tire diameter direction than that of the other part. Thus, each partial thick part 33a is formed so that its elongation in a tire diameter direction during expansion is further delayed than the other part. Consequently, it is possible to execute vulcanization molding while preventing part of the rubber of an unvulcanized tire T from entering between sectors 23a before circumferential end parts of the sectors 23a are completely brought into contact with each other. Accordingly, it is possible to achieve reduction in vibration and noise during vehicle running due to deterioration in uniformity. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to a tire vulcanization bladder and a tire vulcanization method used, for example, in the manufacture of pneumatic tires for automobiles.

In general, in the manufacture of this type of pneumatic tire, the respective constituent members of the tire are bonded together to form an unvulcanized tire, and then the unvulcanized tire is vulcanized by a vulcanizer. As this vulcanizing apparatus, as shown in FIG. 5, the bladder 2 made of a flexible film is inflated inside the unvulcanized tire T arranged in the mold 1, thereby There is known one in which the inner surface is pressurized by a bladder 2 (for example, see Patent Document 1). In this case, the mold 1 arranged on the outer peripheral surface side of the unvulcanized tire T is divided into a plurality of sectors 1a in the tire circumferential direction, and the mold 1 is moved by moving each sector 1a inward in the tire radial direction. The unvulcanized tire T is vulcanized between the mold 1 and the bladder 2 by expanding the bladder 2 while reducing the diameter of the bladder 2.
JP 2002-254435 A

  However, in the vulcanizing apparatus, when the diameter of the mold 1 is reduced, the unvulcanized tire T is pressurized from the inside by the bladder 2 before the circumferential ends of the sectors 1a completely come into contact with each other. As shown in FIG. 5, a so-called overflow in which a part of the rubber of the unvulcanized tire T enters between the sectors 1 a easily occurs. If such an overflow occurs, the thickness of the outer peripheral surface of the tire after vulcanization becomes uneven, and the uniformity of the finished tire deteriorates, causing vibration and noise during vehicle running. It was.

  The present invention has been made in view of the above-mentioned problems, and an object thereof is to provide a part of rubber of an unvulcanized tire between each sector of a mold when pressurizing the inner surface of the unvulcanized tire. An object of the present invention is to provide a tire vulcanizing bladder and a tire vulcanizing method in which no tire enters.

  In order to achieve the above object, the present invention is provided in a tire vulcanizing apparatus in which a mold disposed on the tire outer peripheral surface side is divided into a plurality of sectors in the tire circumferential direction, and is provided in an unvulcanized tire in the mold. In the tire vulcanization bladder that pressurizes the inner surface of an unvulcanized tire by being arranged and inflated, the portion corresponding to the division position of each sector is slower in the tire radial direction during expansion than the other portions. It is formed to become.

  As a result, the portion corresponding to the division position of each sector has a slower expansion in the tire radial direction when inflated than the other portions. The rubber of the unvulcanized tire corresponding to the division position does not become thicker than the rubber of other portions, and the rubber is partially vulcanized without entering a portion of the rubber of the unvulcanized tire between the sectors.

  In order to achieve the above object, the present invention arranges a mold divided into a plurality of sectors in the tire circumferential direction on the outer peripheral surface side of the unvulcanized tire and expands the bladder disposed in the unvulcanized tire. In the tire vulcanizing method in which the unvulcanized tire is vulcanized and molded by pressurizing the inner surface of the unvulcanized tire, the portion corresponding to the division position of each sector is more than the other portion. The tire is inflated so that the elongation in the tire radial direction at the time of inflation is slow.

  As a result, the portion corresponding to the division position of each sector in the bladder is slower to expand in the tire radial direction when inflated than the other portions. The rubber of the unvulcanized tire corresponding to the division position of the sector does not become thicker than the rubber of other parts, and the rubber is partially vulcanized without entering the rubber between the sectors. .

  According to the present invention, it is possible to perform vulcanization molding without allowing a portion of the rubber of the unvulcanized tire to enter between the sectors before the circumferential ends of the sectors are completely in contact with each other. It is possible to reduce vibration and noise when the vehicle travels due to deterioration.

  1 to 4 show an embodiment of the present invention. FIG. 1 is a side sectional view of a vulcanizing apparatus equipped with a tire vulcanizing bladder, FIG. 2 is a plan sectional view of an essential part thereof, and FIG. FIG. 4 is a view showing the test results.

  The vulcanizing apparatus 10 shown in the figure includes a mold 20 disposed on the outer surface side of the unvulcanized tire T and a bladder unit 30 disposed on the inner surface side of the unvulcanized tire T. An unvulcanized tire T disposed between the bladder unit 30 and the bladder unit 30 is vulcanized and molded.

  The mold 20 includes a pair of upper and lower upper molds 21 and 22 corresponding to both side surfaces of the unvulcanized tire T, and an intermediate mold 23 corresponding to the outer peripheral surface of the unvulcanized tire T. It is divided into a plurality of sectors 23a in the tire circumferential direction. The upper mold 21 and the lower mold 22 are supported by substrates 21a and 21b, respectively, and the upper mold 21 moves in the vertical direction together with the substrate 21a. Each sector 23a of the middle mold 23 has a cavity for molding a tread pattern on the inner peripheral surface, and is supported by the substrate 21a via a support portion 23b so as to be movable in the tire radial direction.

  The bladder unit 30 includes a pair of upper and lower bladder clamps 31 and 32 and a flexible bladder 33 supported by the bladder clamps 31 and 32. The bladder 33 is reinforced by a resin fiber cord or a metal cord. Made of vulcanized rubber. Each bladder clamp 31, 32 is supported by a support shaft 34 so as to be movable in the vertical direction, and the lower bladder clamp 32 is provided with a steam inlet 32a. That is, the bladder 33 is expanded by supplying heated steam from the steam inlet 32 a to the space closed by the bladder clamps 31, 32 and the bladder 33. Further, a portion corresponding to the division position of each sector 23a in the bladder 33 is provided with an uneven thickness portion 33a having a larger thickness in the tire radial direction than the other portions, and the uneven thickness portion 33a is the maximum thickness in the tire radial direction. The thickness t1 is formed to be larger by 1 mm or more and 2 mm or less than the thickness t2 (for example, 5 mm) of the other portion in the tire radial direction. That is, the uneven thickness portions 33a are provided on the inner peripheral surface of the bladder 33 at intervals in the circumferential direction, and are formed so that the thickness gradually increases from both ends toward the center.

  When the unvulcanized tire T is vulcanized by the vulcanizing apparatus configured as described above, the bladder unit 30 contracted by the bladder 33 is disposed on the radially inner side of the unvulcanized tire T, and the unvulcanized tire After T is arranged in the mold 20, the bladder 15b of the bladder unit 15 is expanded by heated steam. As a result, the inner surface of the unvulcanized tire T is pressurized and heated by the bladder 33, and the outer surface of the unvulcanized tire T is molded by the mold 20.

  At that time, the uneven thickness portion 33a corresponding to the division position of each sector 33a in the bladder 33 is formed so as to be thicker in the tire radial direction than the other portions, and as shown in FIG. Further, the expansion in the tire radial direction at the time of expansion is slower than in other portions. Thereby, the rubber of the unvulcanized tire T corresponding to the division position of each sector 33a does not become thicker than the rubber of other parts before the circumferential ends of each sector 23a completely contact each other. As shown in FIG. 3 (b), the rubber is partially vulcanized and molded without entering between the sectors 23a.

  Here, with respect to the example of the present invention and the conventional example, a quietness test during running of the vehicle was performed, and the result shown in FIG. 4 was obtained. In this case, tires vulcanized and molded with a bladder having the uneven thickness portion 33a were used in the examples, and tires vulcanized and molded with a bladder having a uniform thickness in the tire circumferential direction were used in the conventional examples. In the examples and conventional examples, tires having a tire size of 195 / 65R15 were used.

  In this test, a tire with an air pressure of 220 kPa is mounted on a domestic car with a displacement of 2000 cc and traveled at a speed of 100 km / h, and the sound pressure is measured with a microphone installed in the passenger compartment. Evaluated as being. As a result of the test, the results of the examples were superior to the conventional examples in quietness.

  As described above, according to the present embodiment, the portion corresponding to the division position of each sector 23a of the mold 20 in the bladder 33 is formed so that the expansion in the tire radial direction during expansion is slower than the other portions. Further, before the circumferential ends of the sectors 23a completely come into contact with each other, the vulcanized molding can be performed without any rubber of the unvulcanized tire T entering between the sectors 23a. It is possible to reduce vibration and noise during traveling.

  In this case, since the portion corresponding to the division position of each sector 23a in the bladder 33 is formed by the uneven thickness portion 33a having a larger thickness in the tire radial direction than the other portions, the bladder 33 is partially thickened. Therefore, the uneven thickness portion 33a can be formed by molding so as to be different, and the bladder 33 having the uneven thickness portion 33a can be manufactured easily and at low cost.

  Further, the uneven thickness portion 33a is formed so that the maximum thickness t1 in the tire radial direction is larger by 1 mm or more and 2 mm or less than the thickness t2 in the tire radial direction of other portions. The difference in thickness between the two is not too small, and a sufficient overflow reduction effect can be obtained. In addition, since the difference in thickness between the uneven thickness portion 33a and other portions is not too large, deterioration of uniformity due to insufficient pressurization of the unvulcanized tire T in the uneven thickness portion 33a can be prevented.

  In the above-described embodiment, by partially increasing the thickness of the bladder 33 in the tire radial direction, the portion corresponding to the division position of each sector 23a is more stretched in the tire radial direction during expansion than the other portions. Although what was formed so that it became slow was shown, other parts, such as forming the part corresponding to the division position of each sector 23a with a material harder than other parts, or providing a reinforcing material or unevenness partially, etc. Depending on the configuration, it is possible to slow the elongation in the tire radial direction during expansion.

Side surface sectional drawing of the vulcanization | cure apparatus provided with the bladder for tire vulcanization which shows one Embodiment of this invention Cross section of the main part of the vulcanizer An enlarged plan sectional view of the main part of the vulcanizer Diagram showing test results Main part enlarged plan sectional view of a vulcanizing apparatus showing a conventional example

Explanation of symbols

  DESCRIPTION OF SYMBOLS 10 ... Tire vulcanizing device, 20 ... Mold, 23a ... Sector, 33 ... Bladder, 33a ... Uneven thickness part, T ... Unvulcanized tire.

Claims (4)

A mold placed on the outer peripheral surface of the tire is provided in a tire vulcanizing apparatus that is divided into a plurality of sectors in the tire circumferential direction, and is placed in an unvulcanized tire in the mold to expand, thereby unvulcanized. In the tire vulcanization bladder that pressurizes the inner surface of the tire,
The tire vulcanization bladder is characterized in that the portion corresponding to the division position of each sector is formed so that the expansion in the tire radial direction during expansion is slower than the other portions. The tire vulcanization bladder according to claim 1, wherein a portion corresponding to the division position of each sector is formed so that a thickness in a tire radial direction is larger than that of other portions. The tire vulcanization bladder according to claim 2, wherein the portion corresponding to the division position of each sector is formed so that the maximum thickness in the tire radial direction is larger by 1 mm or more and 2 mm or less than the other portions. . By placing the mold divided into multiple sectors in the tire circumferential direction on the outer peripheral surface side of the unvulcanized tire, and inflating the bladder disposed in the unvulcanized tire to pressurize the inner surface of the unvulcanized tire In the tire vulcanization method in which an unvulcanized tire is vulcanized and molded,
A tire vulcanizing method, wherein the bladder is inflated so that a portion corresponding to a division position of each sector has a slower elongation in the tire radial direction when inflated than other portions.

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