JP2009269338A - Tire vulcanizer and tire vulcanizing method - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To dispense with a wide storage space at the temporary storage of a low cover, and suppress the generation of TWIST in a vulcanization process. <P>SOLUTION: A tire vulcanizer comprises a means for remedying bead deformation which remedies upper and bottom beads at the same time in such a way that a bead deformation coefficient shown by a following formula (1) is 100 to 105% in each of parts by the use of a roader in the upper bead on a funnel cover set forth horizontally and a centering device in the bottom bead on a supporting plate of the funnel cover and a means for remedying bead parallel which remedies a bead parallel index shown by a deviation angle from a parallel position between the upper bead of the bottom bead down to 5° or lower, and also a tire vulcanizing method using the tire vulcanizer is provided; (1) bead deformation coefficient(%)=(a/b)×100 wherein a is an outer circumscribed diameter in a bead, and b is an inner circumscribed diameter in a bead. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to a tire vulcanizer and a tire vulcanization method, and more particularly to a tire vulcanizer and a tire vulcanization method having means and a method for correcting a raw cover having a deformed bead portion.

  In order to form the tire groove in the tread part by combining the rubber of the raw cover (the tire in which the rubber is not vulcanized and the tire groove is not formed in the tread part) with the elastic body, the raw cover is formed with a bladder or a mold. The tire is vulcanized by heating.

  Specifically, first, the bead portion of the raw cover is centered on the bead ring of the vulcanizing mold of the vulcanizer and pushed into a seat, and at the same time, the raw cover is put on the outer peripheral side of the bladder included in the vulcanizer. Then, the raw cover is attached, and then the vulcanization mold on the outer periphery of the raw cover is closed, and the bladder is further inflated to press the externally fitted raw cover from the inside. Under this state, the raw cover is heated together with the bladder and the vulcanization mold for a predetermined time to vulcanize the raw cover (paragraphs 0002, 0003, FIGS. 1 and 2 of Patent Document 1).

  The raw cover that has been molded in this way is temporarily stored until post-molding vulcanization, but if the period is long, the main constituent material of the raw cover is in a state of being elastic and plastic. Since it is rubber, so-called raw rubber or rubber in a state close thereto, the shape of the bead portion is easily deformed from a perfect circle, and the parallelism between the bead portions is likely to change. In particular, in summer when the temperature is high, the uncovered rubber tends to be deformed because the unvulcanized rubber becomes more plastic.

  When the deformed raw cover is attached to the mold as it is and vulcanized, the deformed raw cover is mounted off the center of the tire vulcanizer, so the bead portion of the raw cover is attached to the vulcanizing mold. TWIST, which is an uneven thickness defect of the bead part in which the bead part of the product tire rises to the bead ring of the vulcanization mold. Will occur.

  In a vehicle equipped with a product tire in which TWIST is generated, the tire RFV (Radial Force Variation) is increased, noise is generated, and the ride quality of the vehicle is deteriorated.

As a method for suppressing deformation of the raw cover during temporary storage, measures such as storing the raw cover in a horizontal state are taken.
JP 2006-27174 A

  However, in order to store the raw cover in a horizontal state, there are many problems such as requiring a large storage space.

  For this reason, development of the technique which does not require a large storage space for temporary storage of a raw cover and can suppress generation | occurrence | production of TWIST in a vulcanization process was desired.

In order to solve the above-described problems, a tire vulcanizer according to the present invention includes:
A tire vulcanizer for vulcanizing a raw cover, as a means prior to vulcanization of the raw cover,
Using the loader in the upper bead portion of the row cover installed horizontally, and using the centering device of the row cover cradle in the lower bead portion, the bead deformation degree expressed by the following equation (1) is: Bead deformation degree correcting means for simultaneously correcting the upper and lower bead portions so as to be 100 to 105% in each bead portion;
It has bead parallelism correction means for correcting the bead parallelism represented by the deviation angle from the parallel of the upper mold bead part and the lower mold bead part to be 5 ° or less. Yes.
Degree of bead deformation (%) = (a / b) × 100 (1)
Where a: the diameter of the circumscribed circle in the bead portion
b: Diameter of the inscribed circle in the bead portion

The tire vulcanization method according to the present invention includes:
A tire vulcanizing method for vulcanizing a raw cover, and as a step prior to vulcanizing the raw cover,
Using the loader in the upper bead portion of the row cover installed horizontally, and using the centering device of the row cover cradle in the lower bead portion, the bead deformation degree expressed by the following equation (1) is: A bead deformation degree correcting step for simultaneously correcting the upper and lower bead parts so as to be 100 to 105% in each bead part;
A bead parallelism correcting step for correcting the bead parallelism represented by a deviation angle from the parallel of the upper die bead portion and the lower die bead portion to be 5 ° or less. Yes.
Degree of bead deformation (%) = (a / b) × 100 (1)
Where a: the diameter of the circumscribed circle in the bead portion
b: Diameter of the inscribed circle in the bead portion

Further, the tire vulcanizing method according to the present invention includes:
The total correction time performed in the bead deformation degree correction step and the bead parallelism correction step is at least 5 minutes or longer.

  According to the present invention, since the deformation of the deformed raw cover is corrected prior to vulcanization, it is not necessary to store the raw cover in a horizontal state, and a large storage space is not required. Moreover, since the raw cover that has been deformed by correction is vulcanized, the occurrence of TWIST can be suppressed in the vulcanization process.

  Furthermore, the present invention can correct the raw cover easily and in a short time using an extremely simple correction method. Moreover, since it is not necessary to add a new equipment to the conventional tire vulcanizer in the correction, the equipment cost is not increased.

  The best mode for carrying out the present invention will be described below with reference to the drawings. Note that the present invention is not limited to the following embodiments. Various modifications can be made to the following embodiments within the same and equivalent scope as the present invention.

A. Outline of Tire Vulcanizer and Tire Vulcanizing Method According to the Present Embodiment FIG. 1 is a diagram schematically showing main parts of the tire vulcanizer according to the present embodiment. In FIG. 1, reference numeral 10 denotes a horizontal cover to be corrected, which has an upper bead portion 11a, a lower bead portion 11b, a sidewall portion 12, and a tread portion 13. Reference numeral 20 denotes a loader that holds the upper bead portion 11a. Reference numeral 30 denotes a raw cover cradle, and reference numerals 35, 36, 37, and 38 denote four rollers provided in the centering device of the raw cover cradle 30.

  The actual low cover 10 has a skeleton as a skeleton, bead wires in the upper and lower bead portions 11a and 11b, carcass cords in the sidewall portions 12 and tread portions 13, and in the tread portion 13. 1 has a much more complicated structure than that shown in FIG. 1, such as a breaker cord. However, since these are well-known matters, illustration and explanation are omitted.

  Further, in an actual tire vulcanizer, a bladder is inserted inside the raw cover 10, and the lower die bead portion 11 b is fixed to the raw cover receiving base 30 at the lowermost end, and further, a gold is attached to the outer periphery of the raw cover 10. The mold is placed. Furthermore, for heating for vulcanization, platens are installed at the top and bottom of the vulcanization mold, steam of a predetermined temperature and pressure is passed through it, and the heating induction coil inside the bladder is energized. Then, the raw cover 10 is vulcanized by performing predetermined heating while controlling each part of the raw cover 10. However, since these matters are not directly related to the present invention, illustration and explanation are omitted.

  The deformed low cover 10 is corrected by a loader 20 or rollers 35 to 38 for bead deformation, which will be described later, and further, bead parallelism, which will be described later by a loader 20 and a raw cover pedestal 30, is corrected. The deformation of the raw cover 10 is corrected. The raw cover 10 whose deformation has been corrected is vulcanized and becomes a tire in which TWIST is suppressed.

B. Correction of Raw Cover Deformation The procedure for correcting deformation of the raw cover will be described in detail below.
1. Correction of the degree of bead deformation Prior to vulcanization, first, when placed horizontally, the bead deformation degree of the opposing bead portions that are opposite to each other is measured, and correction according to the degree of bead deformation is performed.

(1) Measurement of bead deformation degree FIG. 2 is a diagram for explaining the bead deformation degree, and shows the bead deformation degree of the upper bead portion 11a as an example. In FIG. 2, two large and small circles indicated by broken lines are a circumscribed circle and an inscribed circle in the upper mold bead portion 11a, and the diameters thereof are a and b, respectively. In the present invention, the bead deformation degree is represented by a value calculated using the following equation.
Degree of bead deformation (%) = (a / b) × 100

  From the above equation, it can be seen that the bead deformation degree is 100% for a perfect circle, and the bead deformation degree increases from 100% as the deviation from the perfect circle increases.

  As a rough measurement method at the manufacturing site, deformation in the bead portion is generally deformed from a perfect circle to an ellipse. For example, an elliptical major axis is set in the horizontal direction. Measure the diameter with a measure and set it to a, and then measure the minor axis of the ellipse in the longitudinal direction as b and calculate the above formula using the obtained a and b. Therefore, it is possible to measure the degree of bead deformation without any practical problem.

  The above measurement is performed on each of the upper bead portion and the lower bead portion. If the bead deformation degree is 100 to 105%, manufacturing defects such as TWIST due to the bead deformation degree do not occur at the time of vulcanization, and thus correction is not necessary. When the bead deformation exceeds 105%, the bead deformation is corrected as described below.

(2) Correction of bead deformation degree In the present invention, the bead deformation degree of each of the upper bead part and the lower bead part is corrected by carrying the raw cover to the raw cover cradle of the vulcanizer by a loader and performing centering. In the installed state, it is performed at the same time up and down. By correcting the bead deformation degree at the same time for the upper die bead portion and the lower die bead portion, the bead portion of the deformed raw cover can be brought close to a perfect circle.

(A) Correction of bead deformation degree of lower die bead part FIG. 3 is a diagram for explaining correction of bead deformation degree in the lower die bead part 11b, (a) is a view seen from above, (b). FIG.

  As shown in FIG. 3, since b has a short diameter, it is necessary to increase the diameter, and the rollers 35 and 37 are moved outward as indicated by thick arrows. Note that the amount of movement is appropriately determined based on the degree of bead deformation obtained in the immediately preceding measurement.

(B) Correction of the degree of bead deformation of the upper type bead part Correction of the degree of bead deformation of the upper type bead part is performed using a loader because it is above, but the method is basically the above described lower type bead part. This is the same as correcting the degree of bead deformation. However, instead of using four rollers, the upper bead gripping part of the loader is adjusted.

2. Correction of bead parallelism Subsequently, the bead parallelism of the raw cover is measured.

(1) Measurement of bead parallelism FIG. 4 is a diagram for explaining bead parallelism, where 11c drawn by a dotted line shows a perspective cross section of the upper bead portion 11a, and 11d drawn by a dotted line is a lower bead The cross section which looked at the part 11b was shown. 11c and 11d indicate that the bead parallelism is not actually represented by a straight line slope but a circular cross section slope. Reference numeral 90 denotes a line indicating the lower die bead portion 11b, and reference numeral 91 denotes a line indicating the upper die bead portion 11a.

  The bead parallelism represents a deviation from the parallel of the upper die bead portion 11a and the lower die bead portion 11b as a relative inclination angle (indicated by θ in FIG. 4). If the line 91 indicating the upper bead part 11a is completely parallel to the line 90 indicating the lower mold bead part 11b, the bead parallelism is 0 °.

  When the low cover 10 is deformed, the line indicating the upper bead portion 11a is not parallel to the line 90, and is, for example, ascending to the right like the line indicated by 92. That is, the line 92 is deviated from the line 91 parallel to the line 90, and the angle θ formed by the line 91 and the line 92 is the bead parallelism. Specifically, the angle obtained when the upper die bead portion 11a and the lower die bead portion 11b are placed is measured.

  If the bead parallelism is 5 ° or less, manufacturing defects such as TWIST due to the bead parallelism do not occur during vulcanization, and thus correction is not necessary. When the bead parallelism exceeds 5 °, the bead parallelism described below is corrected.

(2) Correction of bead parallelism In order to correct bead parallelism, the upper bead portion 11a and the lower bead portion 11b shown in FIG. 1 are pulled in the vertical direction with a stretch of 105 to 120% of the original bead width. To do. Thereby, the parallel with the upper type bead part 11a and the lower type bead part 11b can be taken out. The bead parallelism correction can be fixed by holding this state for a predetermined time.

3. Completion of correction of raw cover After correcting the degree of bead deformation and subsequent correction of bead parallelism, when the predetermined degree of bead deformation and bead parallelism are obtained, correction of the raw cover is completed. The correction time is preferably (vulcanization time-1) minutes as a whole, and is preferably at least 5 minutes. Since the correction time is 5 minutes or longer and no rapid correction is performed, stress that adversely affects the raw cover is not accumulated, and further, the corrected bead deformation degree and bead parallelism are fixed, and the deformation does not return. Stabilize.

4). Thereafter, the raw cover is vulcanized, but since the raw cover is appropriately corrected, the occurrence of TWIST during vulcanization can be suppressed.

C. Examples and Comparative Examples Examples 1 and Comparative Examples 1 to 3 are shown below to describe the present invention more specifically.
For the low-covered tire size 195 / 65R15 with over 10,000 tires, correction is performed under the conditions of bead deformation, bead parallelism, and correction time shown in Table 1, then vulcanized by heating, and after vulcanization The occurrence rate of TWIST was determined. The results are also shown in Table 1.

  As shown in Table 1, in Example 1 where the bead deformation is 100 to 105%, the bead parallelism is 5 ° or less, and the correction time is 5 minutes or more, the TWIST occurrence rate is 0.01. It can be seen that, by appropriate correction, a great effect is exhibited in preventing the occurrence of TWIST.

  In contrast, in the case of Comparative Example 1 where the bead parallelism is 5 ° or less but the bead deformation is over 105% and the correction time is less than 5 minutes, the TWIST occurrence rate is 0.05%. It can be seen that insufficient correction of the bead deformation degree and insufficient correction time have a significant adverse effect on the occurrence of TWIST.

  The bead deformation rate is in the range of 100 to 105%, but the bead parallelism is more than 5 ° and the correction time is less than 5 minutes. It can be seen that insufficient correction of bead parallelism and insufficient correction time have a significant adverse effect on the occurrence of TWIST.

  And in the case of the comparative example 3 whose bead parallelism is 5 degrees or less but bead deformation degree is more than 105% and the correction time is less than 5 minutes, the TWIST occurrence rate becomes 0.06%, and the bead It can be seen that insufficient correction of the degree of deformation and insufficient correction time have a significant adverse effect on the occurrence of TWIST.

  As described above, according to the present invention, the raw cover can be corrected easily and in a short time by using the extremely simple method as described above. As a result, a product tire in which occurrence of TWIST is suppressed can be provided. Further, a loader, a raw cover cradle, a centering device, etc. used in the correction of the raw cover according to the present invention are already provided in the conventional tire vulcanizer and do not need to be newly added when applying the present invention. Therefore, it does not lead to an increase in equipment costs.

It is a schematic diagram which shows the principal part of the tire vulcanizer which concerns on embodiment of this invention. It is a figure explaining a bead deformation degree. It is a figure explaining correction of the bead deformation degree of a lower model bead part. It is a figure explaining bead parallelism.

Explanation of symbols

DESCRIPTION OF SYMBOLS 10 Low cover 11 Bead part 11a Upper mold bead part 11b Lower mold bead part 11c Cross section 11d of upper mold bead part Cross section 12 of lower mold bead part Side wall part 13 Tread part 20 Loader 30 Low cover cradle 35, 36, 37, 38 Roller 90 Line indicating the lower bead portion 91 Line indicating the inclination of the upper bead portion when the bead parallelism is 0 ° 92 Line indicating the actual inclination of the upper bead portion

Claims (3)

A tire vulcanizer for vulcanizing a raw cover, as a means prior to vulcanization of the raw cover,
Using the loader in the upper bead portion of the row cover installed horizontally, and using the centering device of the row cover cradle in the lower bead portion, the bead deformation degree expressed by the following equation (1) is: Bead deformation degree correcting means for simultaneously correcting the upper and lower bead portions so as to be 100 to 105% in each bead portion;
It has bead parallelism correction means for correcting the bead parallelism represented by the deviation angle from the parallel of the upper mold bead part and the lower mold bead part to be 5 ° or less. Tire vulcanizer.
Degree of bead deformation (%) = (a / b) × 100 (1)
Where a: the diameter of the circumscribed circle in the bead portion
b: Diameter of the inscribed circle in the bead portion A tire vulcanizing method for vulcanizing a raw cover, and as a step prior to vulcanizing the raw cover,
Using the loader in the upper bead portion of the row cover installed horizontally, and using the centering device of the row cover cradle in the lower bead portion, the bead deformation degree expressed by the following equation (1) is: A bead deformation degree correcting step for simultaneously correcting the upper and lower bead parts so as to be 100 to 105% in each bead part;
A bead parallelism correcting step of correcting the bead parallelism represented by a deviation angle from the parallel of the upper die bead portion and the lower die bead portion to be 5 ° or less. Tire vulcanizing method.
Degree of bead deformation (%) = (a / b) × 100 (1)
Where a: the diameter of the circumscribed circle in the bead portion
b: Diameter of the inscribed circle in the bead portion   The tire vulcanizing method according to claim 2, wherein the total correction time performed in the bead deformation degree correcting step and the bead parallelism correcting step is at least 5 minutes or longer.

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