JPH01184106A - Dome-type vulcanizing apparatus - Google Patents

Abstract

PURPOSE:To reduce difference in degrees of vulcanization in a thick part and a thin part and to attempt to improve quality of a product i.e., a tire, by providing a path for a heating medium both ends of which are only opened on the outer face of a vulcanization mold, an intermediate part of which is passed through on the neighbor of a thick part of a raw tire and wherein a heating medium is passed through, in the vulcanization mold. CONSTITUTION:A raw tire 6 is put in a vulcanization mold 27 and the whole vulcanization mold 27 is heated by feeding a heating medium for vulcanization of high temp. and high pressure in a closed space 22. If the raw tire 6 is large, a thick part, a bead part 11 and a shoulder part 35 of the raw tire 6 have large heat capacities and a large amt. of heat is therefore taken from parts of the vulcanization mold being brought into contact with them. Therefore, the temp. tends to drop more than the temp. of other parts, e.g., a side wall part 9. However, as a number of outer heating medium paths 33 and 34 and inner heating medium paths 36 and 37 are provided in the vulcanization mold 27, a heating medium in the closed space 22 is passed through them. Heat transfer area in the neighbor of the bead part 11 and the shoulder part 35 is thereby increased and the temp. becomes close to the temp. of other parts in the vulcanization mold 27. Vulcanization of the bead part 11 and the shoulder part 35 is thereby accelerated.

Description

[Detailed description of the invention] 2-1 The present invention relates to a dome-shaped vulcanization device.

In general, dome-shaped vulcanizers are used to vulcanize large or extra-large tires, such as truck and bus tires, aircraft tires, and off-road tires. In such a dome-shaped vulcanizing device, a vulcanizing heat medium is injected into the closed space inside the dome, and the vulcanizing mold provided in the closed space is vulcanized by the vulcanizing heat medium. The raw tire inside the vulcanization mold is vulcanized.

However, in large and extra-large tires such as those mentioned above, the thick wall parts, such as the shoulder and bead parts, are extremely thick, so the heat capacity of the thick wall parts is extremely large. As it becomes larger, it absorbs a large amount of heat from the surrounding vulcanizing mold, which causes the temperature of the vulcanizing mold near the thick portion to be lower than that of other parts. As a result, the vulcanization speed of thick-walled portions of the tire is significantly slower than the vulcanization speed of thin-walled portions of the tire, such as sidewall portions. However, in order to ensure the quality of the product tire exceeds the specified value, it is necessary to vulcanize the thick-walled parts until they are properly vulcanized, even if it takes a considerable amount of time, which reduces production efficiency. In addition, there is a problem in that the thin wall portion becomes over-vulcanized, leading to a deterioration in the quality of the tire.

. This problem is solved by injecting a vulcanizing heating medium into the sealed space inside the dome, and heating the vulcanizing mold set in the sealed space with the vulcanizing heating medium, thereby causing vulcanization. In a dome-shaped vulcanizing device for vulcanizing a green tire in a mold, the vulcanizing mold has both ends opening only to the outer surface of the vulcanizing mold, and the middle of the opening passing through the vicinity of the thick wall part of the green tire. , a heating medium passage is provided inside the dome through which a vulcanization heating medium flows, and the temperature of the vulcanization mold near the thick wall portion is brought closer to the temperature of other parts to promote vulcanization of the thick wall portion. The problem can be solved by

When a green tire is cured using the dome-shaped vulcanization apparatus of the present invention, the dome and the vulcanization mold are closed and the green tire is housed in the vulcanization mold. Next, a vulcanizing heating medium is injected into the closed space within the dome, the vulcanizing mold is heated by the vulcanizing heating medium, and the green tire is vulcanized by the heated vulcanizing mold. At this time, since the thick wall part of the green tire has a large heat capacity, the vulcanizing mold in the part that is in contact with the thick part takes away a large amount of heat, and the temperature of the vulcanizing mold in other parts is higher than that of the vulcanizing mold in other parts. is about to decrease. However, in this invention, both ends of the vulcanization mold are opened only to the outer surface of the vulcanization mold, that is, they are not opened to the inner surface where the green tire is molded, and the middle part thereof is the thick wall part of the green tire. A heating medium passage was provided in the vicinity, and the vulcanizing heating medium inside the dome was allowed to flow through the heating medium passage, so that the heat transfer area near the thick part increased and the vulcanizing heating medium passed through the thick part. The temperature of the vulcanization mold near the thick part approaches the temperature of other parts. As a result, vulcanization of the thick wall portion is promoted, the overall vulcanization time is shortened, and the difference in degree of vulcanization between the thick wall portion and the thin wall portion is reduced.

Fire Lid 1 Hereinafter, a first embodiment of the present invention will be described based on the drawings.

In FIG. 1.2, 1 is a dome type vulcanizer, and this dome type vulcanizer 1 has a base 3 on which a cylindrical lower dome 2 is formed. A lower platen 4 is fixed to the base 3, and a substantially ring-shaped lower mold 5 is mounted on the lower platen 4. This lower mold 5 has a vulcanization recess 7 on the upper surface on the inner end side, which has the same external shape as the half green tire 6. It contacts the outer surface and the outer surface of the sidewall portion 9 to form a mold thereon. 1O is a lower bead ring, and this lower bead ring 1O contacts the outer surface of the bead portion 11 of the green tire 8 during vulcanization to form a shape on the bead portion 11. An upper dome 21 opening downward is installed above the base 3, and the upper dome 21 is raised and lowered by a lifting mechanism (not shown). And this upper dome 2
When the dome 1 is lowered by the operation of the elevating mechanism and comes into contact with the lower dome 2, the lower and upper domes 2.21 close to form a sealed space 22 inside. In addition, this closed space 22
A high-temperature, high-pressure vulcanizing heating medium, such as steam, is injected into the chamber from a supply mechanism (not shown). An upper platen 23 is fixed to the inner surface of the upper dome 21, and a ring-shaped upper mold 24 that pairs with the lower mold 5 is attached to the lower surface of the upper platen 23. This upper mold 24 has a vulcanized recess 25 on the lower surface of the inner end, which has the same external shape as the remaining half of the green tire 6. It contacts the outer surface of the sidewall portion 8 and performs molding thereon. Then, when the upper mold 24 descends together with the upper dome 21 and comes into contact with the lower mold 5,
The lower and upper molds 5.24 are closed and the green tire 6 is housed inside. 26 is an upper bead ring, and this upper bead ring 28 is attached to the bead portion 1 of the green tire 6 during vulcanization.
The bead portion 11 is molded by contacting the outer surface of the bead portion 11. The lower mold 5 and lower bead ring lO1 mentioned above
The upper mold 24 and the upper bead ring 26 collectively constitute a vulcanization mold 27 provided in the sealed space 22, and the lower dome 2 and the upper dome 21 described above
constitutes a dome 28 as a whole. A number of radial grooves 31, 32 extending in the radial direction and equiangularly spaced from each other are formed in the lower part, the lower part of the upper platen 4.23, the upper surface and the lower surface in contact with the upper mold 5.24, respectively. Both the inner and outer ends in the radial direction of 31 and 32 are closed spaces 22
It is open to 33.34 are the lower and upper molds 5.
a large number of outer heat medium passages each formed in 24;
These outer heat medium passages 33.34 are connected to the radial grooves 31.3.
They are located directly above and directly below 2, respectively. The outer ends of these outer heat medium passages 33, 34 are connected to the lower and upper molds 5.
24, and the inner ends thereof are opened at the lower surface of the lower mold 5 and the upper surface of the upper mold 24, respectively, and communicate with the radial grooves 31 and 32, respectively. Also,
These outer heat medium passages 33, 34 pass through a thick wall portion of the green tire 6, in this embodiment, near the shoulder portion 35, and are bent at this location. In this way, the outer heat medium passages 33.34 are open only to the outer surfaces of the lower and upper molds 5.24,
The inner surfaces of the lower and upper molds 5.24, ie, the inner surfaces of the vulcanization recesses 7.25 in which molding is performed, are not opened. The vulcanizing heat medium in the sealed space 22 is transmitted through these outer heat medium passages 33.34 since both ends of the outer heat medium passages 33.34 are open to the outer surfaces of the lower and upper molds 5.24.
It flows through the inside of. On the other hand, a large number of substantially U-shaped inner heat medium passages 36 are formed at the inner end of the lower mold 5 and the lower bead ring 10, and these inner heat medium passages 36
are also located directly above the radial groove 31 and are equiangularly apart from each other.

On the other hand, a large number of substantially U-shaped inner heat medium passages 37 are also formed at the inner end of the upper mold 24 and the upper bead ring 26, and these inner heat medium passages 37 are also located directly below the radial groove 32. They are equiangularly apart from each other. Ends of the inner heat medium passage 38 are open to the upper and lower surfaces of the lower bead ring 10 and the lower surface of the lower mold 5, and communicate with the sealed space 22 and the radial groove 31, respectively.

On the other hand, the end of the inner heat medium passage 37 is connected to the upper bead ring 26.
and the upper surface of the upper mold 24, and communicate with the sealed space 22 and the radial groove 32, respectively. In addition, the inner heat medium passages 36 and 37 pass through a thick portion of the green tire 6, in the vicinity of the bead portion 11 in this embodiment. In this way, the inner heat medium passages 36 and 37 are connected to the lower mold 5, the lower bead ring 10, and the upper mold 24.
, is open only on the outer surface of the upper bead ring 26, and the vulcanizing heat medium in the closed space 22 flows through the inside thereof. The aforementioned outer heat medium passages 33, 34 and inner heat medium passages 36, 37 are collectively a heat medium passage 38 provided in the vulcanization mold 27.
Configure.

It is preferable that the diameter of such a heating medium passage 38 is 5 mm or more so that the vulcanizing heating medium does not accumulate inside, but this may lead to a decrease in the strength of the vulcanizing mold 27. It shouldn't be. Further, the cross-sectional shape of the heat medium passage 38 may be either circular or polygonal, but the circular shape is superior in terms of strength, and the polygonal shape is superior in terms of increasing the heat transfer area.

Next, the operation of the first embodiment of the present invention will be explained.

A green tire 6 is produced using a dome-shaped vulcanizer l as described above.
When vulcanizing, first, the green tire 6 is laid down on the lower mold 5 and the lower bead ring lo, and then the elevating mechanism is activated to vulcanize the upper dome 21, the upper platen 23, and the upper mold 24. , the upper bead ring 26 is lowered integrally to approach the base 3. The lowering of the upper dome 21 stops when the upper dome 21 contacts the lower dome 2 and the upper and lower domes 21 and 2 are closed, but at this time, a closed space 22 is created inside the upper dome 21 and the lower dome 2. Formed, also the lower and upper molds 5
．． 24 are brought into contact with each other and closed, and the green tire 6 is stored inside. Next, a high-temperature, high-pressure vulcanization heating medium is injected into the closed space 22 through the supply mechanism, and the entire vulcanization mold 27 is heated by the vulcanization heating medium. Then, the green tire 6 inside the vulcanization mold 27 is vulcanized by the heated vulcanization mold 27. Here, the thick portions of the green tire 6, such as the bead portion 11 and the shoulder portion 35, have an extremely large heat capacity when the green tire 6 is a large or extra-large tire. A large amount of heat is removed from the portion of the vulcanization mold 27 that is in contact with the bead portion 11 and the shoulder portion 35. Therefore, the temperature of the vulcanizing mold 27 near the bead portion 11 and the shoulder portion 35 tends to be lower than that of other portions, for example, the vulcanizing mold 27 near the sidewall portion 9. However, as described above, the vulcanization mold 27 has a large number of outer heat medium passages 33.
．． 34, inner heating medium passages 36 and 37 are provided, and the vulcanization heating medium in the closed space 22 is caused to flow through these heating medium passages 38, so that the bead portion 11 and the shoulder portion 3
The heat transfer area in the vicinity of 5, that is, the contact area between the vulcanizing heating medium and the vulcanizing mold 27 increases, and the vulcanizing heating medium approaches the poles of the bead portion 11 and the shoulder portion 35, and the intermediate transmission distance increases. shorten. As a result, the temperature of the vulcanization mold 27 near the bead portion 11 and the shoulder portion 35 during vulcanization approaches the temperature of the vulcanization mold 27 in other parts, promoting vulcanization of the bead portion 11 and the shoulder portion 35. be done. FIG. 3 shows experimental results showing that vulcanization is promoted in the thick interior. Here, the same figure shows the temperature of the thick part when the same large green tire was vulcanized under the same conditions using an inventive mold in which the present invention was implemented and a conventional mold, and the temperature was measured using time as a parameter. It can be seen that the temperature rise is faster when the inventive mold is used. In addition, when we measured the degree of vulcanization in the thick part when the same raw tire was cured under the same conditions for a certain period of time, it was 100 in the index display for the conventional mold, but the inventive mold Then, it becomes 109 in index display,
It can be seen that vulcanization is promoted. in this way,
Since vulcanization in the thick-walled portions of the green tire 6 is promoted, the overall vulcanization time is shortened, and the degree of vulcanization in the thick-walled portions such as the bead portion 11 and the shoulder portion 35 and the sidewall portion 8 are reduced. The difference in the degree of vulcanization in thin-walled areas such as vulcanization is also reduced, improving the quality of the product tire.

FIG. 4.5 is a diagram showing a second embodiment of the present invention. In this embodiment, the outer heat medium passages 33 and 34 have annular passages 41 and 42 forming part of the heat medium passages formed in the lower mold 5 and the upper mold 24, respectively.
The inner heat transfer medium passage 36.3 also communicates with each other by
An annular passage 4 forming a part of the heat medium passage formed in the lower and upper bead rings 10 and 26 respectively
3.44. In this case, the outer heating medium passage 33.34 and the inner heating medium passage 36.37 may serve to supply and discharge the vulcanizing heating medium in the closed space 22 to and from the annular passage 41.42.43.44. , the number of outer heat medium passages 33, 34 and inner heat medium passages 3B, 37 can be reduced, making manufacturing easy and inexpensive. Moreover, in this embodiment, the annular passages 41, 42, 43, 44 surround the thick wall portions, that is, the shoulder portion 35 and the bead portion 11, without any gaps, so that the heat transfer area is widened and The amount of vulcanizing heating medium located near the thick portion increases, and vulcanization of the thick portion is further promoted.

FIG. 6.7 is a diagram showing a third embodiment of the present invention. In this embodiment, the outer heat medium passages 51.52 are formed into a substantially V-shape, and both ends of these outer heat medium passages 51.52 are opened to the outer circumferential surfaces of the lower and upper molds 5.24. Both ends of the inner heat medium passages 53, 54 are opened only to the upper and lower surfaces of the lower bead ring 10 and the upper bead ring 26. As a result, this embodiment eliminates the need for the radial grooves 31, 32 in the first embodiment, making it easier and cheaper to manufacture.

As explained above, according to the present invention, the vulcanization heating medium injected into the sealed space is used to promote vulcanization of the thick walled part of the green tire, so that the entire In addition to shortening the curing time, the difference in the degree of vulcanization between thick and thin parts is also reduced, improving the quality of the product tire. Further, since it is only necessary to form a heat medium passage in the vulcanization mold, it can be applied to an existing vulcanization mold.

[Brief explanation of the drawing]

FIG. 1 is a front sectional view of main parts showing a first embodiment of the present invention;
2 is a sectional view taken along the line II in FIG. 1, FIG. 3 is a graph showing the test results, FIG. 4 is a cross-sectional view taken along the line II--II in FIG. 4, FIG. 6 is a front cross-sectional view of a main part showing a third embodiment of the present invention, and FIG. 7 is a cross-sectional view taken along the line ■--■ in FIG. 1...Dome-shaped vulcanizing device 6...Green tire 11.35...Thick walled part 22
... Sealed air M 27 ... Vulcanization mold 28
...Dome 38...Heat medium passage Patent applicant Brideston Co., Ltd. Agent Patent attorney Ta 1) Toshio Figure 3 Time (minutes) → 4 Figure 7〈Sa, Figure 5 Figure 6

Claims (1)

[Claims] A vulcanizing heating medium is injected into the sealed space in the dome, and the vulcanizing mold provided in the sealed space is heated by the vulcanizing heating medium, thereby vulcanizing the green tire in the vulcanizing mold. In the dome-shaped vulcanizing apparatus, both ends of the vulcanizing mold are opened only to the outer surface of the vulcanizing mold, and part of the opening passes near the thick part of the green tire, and the vulcanizing heat medium in the dome is inside the vulcanizing mold. A dome characterized in that vulcanization of the thick walled portion is promoted by providing a heat medium passage through which the heating medium flows and bringing the temperature of the vulcanization mold near the thick walled portion closer to the temperature of other parts. Mold vulcanization equipment.