JP6033663B2 - Tire vulcanization bladder - Google Patents

Description

  The present invention relates to a tire vulcanization bladder that can suppress generation of tire product scrap due to puncture of a tire vulcanization bladder.

  Conventionally, in the manufacture of tires, a tire vulcanization bladder, which is a rubber bag (hereinafter also simply referred to as “blader”), is inflated and deformed from the inside of a raw tire after the raw tire is mounted on a mold. Thus, the raw tire is pressed against the mold surface and vulcanized while being heated from the inner and outer peripheral sides of the raw tire. The expansion deformation of the bladder is performed by supplying a high-temperature, high-pressure heating / pressurizing medium into the bladder.

  Specifically, as shown in FIG. 5 (a), saturated steam of about 190 ° C. or higher is introduced into the bladder 1a set inside the raw tire T before the start of vulcanization. ), The bladder 1a expands and the raw tire is pressed against the mold surface, and vulcanization is performed.

  Although this bladder 1a is repeatedly used, since it is made of rubber as described above, aging due to an increase in the number of uses, aging due to mechanical fatigue during vulcanization, and repeated use at high temperatures (thermal history) ) May cause the bladder 1a to puncture during tire vulcanization depending on the size of use and the situation of use, for example, due to the fact that the rubber molecules are cleaved due to the lifetime.

  Since such bladder puncture occurs at an unspecified position, if puncture occurs on the inner surface side of the tire T during vulcanization, steam leaks from the inside of the bladder and the vicinity thereof becomes an unvulcanized state. As a tire product, it may become a defective product and reduce productivity.

  For example, as shown in FIG. 6, when the tire T is punctured in the radial direction on the inner surface side (range from the upper bead to the lower bead), the exuded vapor also enters between the inner and the ply, and the vicinity is not added. Since it becomes a sulfur state, it becomes a defective product as a tire product.

  Therefore, in order to reduce the occurrence of defective tires due to the puncture of the bladder 1a, a sensor box in which a sensor for detecting humidity is arranged is attached to the tire vulcanizing device, and the tire vulcanizing device is opened. It has been proposed to detect bladder puncture by introducing steam leaked from the bladder into the sensor box (for example, Patent Documents 1 and 2).

JP 2010-115796 A JP 2012-25033 A

  However, as described above, since the puncture of the bladder occurs at an unspecified position, even if the puncture is detected, the generation of defective products due to the occurrence of the puncture on the inner surface side of the tire cannot be sufficiently reduced. .

  Therefore, the present invention suppresses the occurrence of bladder puncture on the inner surface side of the tire and quickly detects the occurrence of puncture so that the occurrence of defective products due to puncture can be sufficiently reduced. It is an object to provide a sulfur bladder.

The invention according to claim 1
A tire vulcanization bladder used for vulcanization molding of a pneumatic tire,
A tire vulcanizing bladder characterized in that at least one puncture generating portion formed by an annular groove is provided on an upper outer surface where a bladder gauge is thicker than a portion in contact with a tire inner surface.

The invention according to claim 2
The diameter of the puncture generating part is 5 to 10 mm,
2. The tire vulcanizing bladder according to claim 1, wherein a depth of the groove is 60 to 70% of a bladder gauge. 3.

  According to the present invention, it is possible to suppress the occurrence of bladder puncture on the inner surface side of the tire and to quickly detect the occurrence of puncture, thereby sufficiently reducing the occurrence of defective products due to puncture. A sulfur bladder can be provided.

(A) is sectional drawing which shows the conventional bladder, (b) is sectional drawing which shows the bladder which concerns on embodiment of this invention. It is a figure which shows the position of the puncture generation | occurrence | production part of the bladder which concerns on embodiment of this invention. 1 is a cross-sectional view schematically showing a tire vulcanizing apparatus provided with a bladder according to an embodiment of the present invention. (A) is a figure which shows the response level of the puncture detection of the conventional bladder, (b) is a figure which shows the response level of the puncture detection of the bladder which concerns on embodiment of this invention. (A) (b) is a figure explaining the vulcanization method using a bladder. It is a figure explaining the problem by puncture of a bladder.

  Hereinafter, the present invention will be described based on the embodiments.

1. Bladder FIG. 1A is a cross-sectional view showing a conventional bladder, and FIG. 1B is a cross-sectional view showing a bladder according to an embodiment of the present invention.

  The bladder 1 according to the present embodiment is formed of a rubber bag similar to the conventional bladder 1a shown in FIG. 1 (a). However, as shown in FIG. A puncture generating portion 3 is provided by an annular groove portion 2 on the upper outer surface where the bladder gauge is thicker than the portion in contact with the inner surface. That is, in the present embodiment, the puncture generating unit 3 is provided so that puncture in the bladder 1 occurs at a specific location.

  In this way, by providing the puncture generating portion 3 with the portion that is in contact with the tire inner surface being removed and causing the puncture of the bladder 1 in the puncture generating portion 3, the occurrence of puncture on the inner surface side of the tire is suppressed. The occurrence of defective products due to puncture can be sufficiently reduced.

  Unlike the case where puncture occurs on the inner surface side of the tire, by providing the puncture generating portion 3 at a position where the portion in contact with the inner surface of the tire is removed, the steam leaked from the punctured bladder 1 immediately enters the sensor box. Therefore, the occurrence of a puncture can be directly detected, and the puncture of the bladder 1 can be found at an early stage and can be dealt with quickly.

  The puncture generation unit 3 needs to be punctured before other portions, but even if the puncture generation unit 3 is provided, the puncture generation unit 3 is provided with a strength that can maintain the life of the bladder 1 to the same level as in the past.

  From such a viewpoint, the puncture generating portion 3 may be provided at least at one location on the upper outer surface where the bladder gauge is thicker than the portion in contact with the inner surface of the tire, but as shown in FIG. If it is provided at four positions at equal intervals in the direction, the occurrence of puncture can be detected more reliably.

  The diameter of the puncture generating unit 3 is preferably 5 to 10 mm, and by setting the diameter to such a size, steam that can be sufficiently detected by the puncture sensor can be sent to the sensor box.

  Moreover, it is preferable that it is 60 to 70% of the bladder gauge in the location in which the puncture generation part 3 is provided as the depth of the groove part in the puncture generation part 3. By setting it to such a depth, the life of the bladder can be maintained in the same manner as a conventional bladder, which is preferable.

2. Tire Vulcanizing Device FIG. 3 is a cross-sectional view schematically showing a tire vulcanizing device provided with a bladder according to an embodiment of the present invention.

  As shown in FIG. 3, the tire vulcanizing device 4 includes a vulcanizing mold 5, a mold holder 6, and a bladder 1, and supplies a heating and pressing medium to the inside of the bladder 1. , The raw tire T is pressed against the inner surface of the vulcanizing mold 5 and vulcanized.

3. Puncture sensor The puncture sensor A is configured to issue a warning signal when the sensor body S senses a heated and pressurized medium exceeding a predetermined amount. Since water vapor is generally used for the heating and pressurizing medium, a humidity sensor is preferably used for the sensor body S.

  As shown in FIG. 3, a gap 7 is formed between the vulcanizing mold 5 and the mold holder 6 of the tire vulcanizing device 4, and when the puncture of the bladder 1 occurs in the puncture generating unit 3, As described above, the vapor leaking from the bladder 1 into the gap 7 is immediately guided to the inside of the sensor box 9 via the flow path 8. Then, after the humidity change in the sensor box 9 is detected by the sensor body S, it is processed by the amplifier 10 and output to the TP monitor 11, and the change of the numerical value shown on the TP monitor 11 is observed. You can know punk.

  Tires having a tire size of 195 / 65R15 were vulcanized using the bladders of Experimental Examples 1 and 3-6 in which the puncture generating portion was provided with the size (diameter) and the depth of the groove shown in Table 1.

  Vulcanization was performed in the same manner using the bladder of Experimental Example 2 which was the same as described above except that the puncture generating portion was not provided (same as conventional vulcanization).

  In each experimental example, the bladder gauge at the location where the puncture generating portion was provided was 6.0 mm.

  The specific vulcanization was continuously performed using the vulcanizer shown in FIG. 3 until the puncture sensor senses the puncture of the bladder. The number of uses at this time is the life of the bladder.

Then, while confirming the puncture location in each experiment example, generation | occurrence | production of a defective product (scrap tire) was confirmed, and the detection accuracy of puncture was measured.
The results are shown in Table 1.

  As shown in Table 1, when a conventional bladder is used (Experimental Example 2), puncture occurs on the tire inner surface, resulting in tire scrap. It can be seen that bladder puncture is not detected until three tire scraps are made, and the puncture sensor does not respond well.

  On the other hand, in the case of Experimental Examples 1, 3, and 4 in which the puncture generation unit is provided, the puncture generation unit is punctured and no tire scrap is generated. Also, at the same time when the puncture of the bladder occurs, that is, the puncture is detected in the first one, the puncture sensor reaction is good by providing the puncture generating part at a position where the part contacting the tire inner surface is removed. I understand.

  However, the bladder life was 800 times in Experiment 1 and the same as in the conventional example (Experiment 2), but decreased to 600 times and 500 times in Experiments 3 and 4, respectively. This is presumed that the puncture occurrence portion provided in Experimental Example 3 was too large, and in the case of Experimental Example 4 the depth of the groove was too deep, leading to a decrease in bladder life. The

  And in the case of Experimental example 5, since the puncture generation part is too small, it turns out that the effect which provided the puncture generation part is not exhibited. Similarly, in the case of Experimental Example 6, it can be seen that the effect of providing the puncture generating portion is not exhibited because the depth of the groove portion is too shallow.

  Next, the response level in the puncture detection of the conventional bladder and the response level in the puncture detection of the bladder of Experimental Example 1 were measured. The results are shown in FIG. In FIG. 4, (a) shows the result of the conventional bladder, and (b) shows the result of the bladder of Experimental Example 1.

  As shown in the part surrounded by the dotted line in FIG. 4B, it can be seen that the reaction level of the bladder of Experimental Example 1 is improved as compared with the conventional technique.

  As mentioned above, although this invention was demonstrated based on embodiment, this invention is not limited to said embodiment. Various modifications can be made to the above-described embodiment within the same and equivalent scope as the present invention.

DESCRIPTION OF SYMBOLS 1, 1a Bladder 2 Groove part 3 Puncture generation | occurrence | production part 4 Tire vulcanizer 5 Curing mold 6 Mold holder 7 Cavity part 8 Flow path 9 Sensor box 10 Amplifier 11 TP monitor A Punk sensor S Sensor body T Tire

Claims (2)

A tire vulcanization bladder used for vulcanization molding of a pneumatic tire,
A tire vulcanization bladder characterized in that at least one puncture generating portion formed by an annular groove is provided on an upper outer surface where a bladder gauge is thicker than a portion in contact with a tire inner surface. The diameter of the puncture generating part is 5 to 10 mm,
The tire vulcanization bladder according to claim 1, wherein the depth of the groove is 60 to 70% of a bladder gauge.

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