JP2013126726A - Post-cure inflator and method of cooling tire after vulcanization - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a post-cure inflator and method of cooling tire after vulcanization, capable of preventing deterioration of RFV and RRO due to heat shrinkage of a ply by sufficiently cooling the ply in a vulcanization process of the tire in which cooling time is limited and capable of efficiently cooling the tire without need for the large amount of cooling water.SOLUTION: In a post-cure inflator, a sprayer for spraying cooling medium inside the tire, and an air vent for discharging the air inside the tire are provided at a rim. The method of cooling the tire after vulcanization uses the post-cure inflator. The cooing medium is sprayed inside the tire from the sprayer to cool the tire from the inside. The air inside the tire is discharged through an air vent. Thus, the increase in the inner pressure of the tire due to vaporization of the sprayed cooling medium is suppressed, and the inner pressure of the tire is kept constant.

Description

  The present invention relates to a post-cure inflator (PCI) used for manufacturing a tire and a method for cooling a vulcanized tire.

  In the vulcanization process of the tire, the raw tire is vulcanized using a vulcanization mold, and then the high-temperature tire immediately after vulcanization taken out from the vulcanization mold is cooled using a post-cure inflator. This prevents the tire from being deformed.

  In addition, the post-cure inflator is configured such that a tire is mounted on a pair of rims, and a predetermined amount of air is filled in the tire to cool the tire in an inflated state.

  However, the conventional post-cure inflator was designed to naturally cool the tire by sending air at normal temperature into the tire, so the tire must be sufficiently cooled in the vulcanization process where the cooling time is limited. There was a case that could not be.

  Therefore, a post-cure inflator that can efficiently cool the tire by blowing air or mist water from the outside of the tire has been proposed (for example, Patent Document 1).

JP 2007-320151 A

  However, even such a post-cure inflator has a problem that the ply, which is the most important part of the tire, may not be cooled sufficiently in a short time, and a large amount of cooling water is required.

  Therefore, the present invention prevents the ply from thermal shrinkage by sufficiently cooling the ply in a short time in the tire vulcanization process in which the cooling time is restricted, and further eliminates the need for a large amount of cooling water. It is an object of the present invention to provide a post-cure inflator that can be efficiently cooled.

The invention described in claim 1
A post-cure inflator that includes a pair of upper and lower rims that fits into a bead portion of a tire and supports the tire, and that performs pressure cooling in a state in which the tire is filled with internal pressure,
A post-cure inflator characterized in that a sprayer for spraying a cooling medium into a tire and an air vent for exhausting air in the tire are provided on the rim.

The invention described in claim 2
A method for cooling a post-vulcanized tire that cools a high-temperature tire immediately after vulcanization using the post-cure inflator according to claim 1,
Cooling the tire from the inside by spraying a cooling medium into the tire from the sprayer;
By exhausting the air in the tire through the air vent, an increase in the internal pressure of the tire due to evaporation of the sprayed cooling medium is suppressed and the internal pressure of the tire is kept constant. It is a cooling method.

  According to the present invention, by sufficiently cooling the ply in a short time in the tire vulcanization process in which the cooling time is restricted, the deterioration of RFV and RRO due to the thermal shrinkage of the ply is prevented, and a larger amount The tire can be efficiently cooled without the need for cooling water.

It is a figure which shows typically the structure of the principal part of the post-cure inflator of one embodiment of this invention. It is a figure which shows the relationship between the temperature of each part of the tire case in a vulcanization process of an Example, and vulcanization time. It is a figure which shows the relationship between the temperature of each part of the tire case in a vulcanization process of a comparative example, and vulcanization time.

  Hereinafter, the present invention will be described with reference to the drawings based on embodiments.

1. Post Cure Inflator FIG. 1 is a diagram schematically showing a configuration of a main part of a PCI according to an embodiment of the present invention. As shown in FIG. 1, the post-cure inflator 1 includes a support shaft 11, an upper rim 12, a lower rim 13, a sprayer 14 and an air vent 15 provided on the upper rim 12. . In FIG. 1, T is a tire immediately after vulcanization, and is a tire set on a post-cure inflator.

  The upper rim 12 and the lower rim 13 are supported by the support shaft 11 so that the distance between them can be adjusted. The upper rim 12 is provided with a sprayer 14 for spraying cooling water and an air vent 15 for exhausting in order to keep the internal pressure in the tire constant.

  In order to spray the cooling water uniformly on the inner surface of the tire T, the spray holes 14a of the sprayer 14 are arranged at a plurality of positions at equal intervals in the circumferential direction in each of the upper rim 12 and the lower rim 13. Is preferred. Moreover, it is preferable that the spraying direction of the spray hole 14a faces the direction of the tire T.

2. Cooling method of tire after vulcanization Next, a cooling method of the tire after vulcanization using the post-cure inflator 1 of the present embodiment will be described.

(1) First, a high-temperature tire immediately after vulcanization is set in the post-cure inflator 1. That is, after fitting the beads on both sides of the high-temperature tire T immediately after vulcanization to the upper rim 12 and the lower rim 13, the distance between the upper rim 12 and the lower rim 13 is the size of the tire T. The tire T is fixed to a predetermined size according to the above.

(2) Next, in order to inflate the tire T and keep it in a stable shape, the internal pressure of the tire T is a predetermined magnitude, specifically about 2.0 kPa for SP (passenger car) size, and for ST (SUV) size Air is injected so as to be about 3.0 kPa.

(3) Next, water is sprayed from the sprayer 14. The sprayed water removes heat from the tire T and evaporates at the same time. The tire is rapidly cooled from the inside by the evaporation heat at this time, and the ply near the inside of the tire is also rapidly cooled.

  Note that the total spray amount of water is determined according to the heat amount of the tire. For example, since the temperature of a tire immediately after vulcanization is usually about 185 ° C., the amount of heat lost until the temperature of the tire decreases from 185 ° C. to room temperature (30 ° C.) and the amount of heat of evaporation of sprayed water Specifically, the total spray amount is calculated by the following equation.

Tire heat amount = tire mass × specific heat (1.1) × temperature change (185 ° C.-30 ° C.)
Total spray amount (g) = tire heat amount ÷ water evaporation heat (540 cal / g)

  The spray pressure of the sprayer 14 is preferably 2.0 kPa or more, and the spray amount is preferably adjustable in the range of 0 to 300 ml / min.

  The sprayed water evaporates inside the tire T and increases in volume, but is exhausted from the air vent 15, so that the internal pressure is kept constant.

  The pressure adjustment range of the air vent 15 is preferably 0 to 5 kPa. The operating pressure of the air vent is adjusted to an appropriate value according to the tire size, the amount of water sprayed, and the like.

3. Effects of the present embodiment (1) According to the present embodiment, a sprayer for spraying water (cooling medium) is provided in the tire, and the tire is cooled from the inside by spraying the cooling medium from the sprayer into the tire. Compared to the conventional method of cooling from the outside of the tire, the ply provided near the inside of the tire can be efficiently cooled, and the heat of the water is used to efficiently heat the ply. Can be taken away.

  For this reason, the ply can be sufficiently cooled in a short time in the PCI process after vulcanizing the tire where the cooling time is restricted, the heat shrinkage of the ply after post-cure inflation is suppressed, and the RFV and RRO are deteriorated. Can be prevented. Furthermore, since it can cool efficiently, a large amount of cooling water is not required. Further, by setting the heat quantity of the tire to the evaporation heat of the spray water, it is possible to prevent water from being accumulated inside the tire and to cool the tire uniformly.

(2) In addition, an air vent for exhausting the air in the tire is provided, and the air in the tire is exhausted through the air vent, so that an increase in the internal pressure of the tire due to evaporation of sprayed water is suppressed and the internal pressure of the tire is made constant. Since it can be maintained, the tire can be kept in an appropriately inflated state during post-cure inflation.

(3) Since it has said characteristic, a tire uniformity can be improved.

(4) Furthermore, according to the present embodiment, since the PCI time can be shortened by efficient cooling, the productivity can be improved and the vulcanizer cost by 1 cure PCI can be reduced. It is possible to save space.

  Next, based on an Example, it demonstrates more concretely.

(1) Examples and Comparative Examples Examples are examples in which the post-cure inflator of the present embodiment that is cooled by water spray is used. The comparative example is an example using a post-cure inflator by natural cooling.

(2) Test conditions Test conditions are as follows. In addition, since the test conditions of a comparative example are not spraying water, they are (a)-(h).
(A) Tire size: 185 / 65R15
(B) Vulcanization temperature: Jacket ... 188 ° C
Platen ... 183 ° C
(C) PCI rim interval: 160 mm
(D) PCI time: 15 minutes, 2 cure cycle (e) PCI internal pressure: 2.0 kPa
(F) Number of tests: n = 8
(G) Tire weight: 7.5kg
(H) Tire heat quantity: 1279 kcal
(I) Total spray amount: 1279 / 0.54 = 2370 ml
(J) Spraying time: 2370 (ml) / 300 (ml / min) = 7.9 min
(In the experiment, it was set to 8 min.)
In addition, the total spray amount of the Example was calculated from the above formula, and the spraying time was set with the spray rate set to 300 ml (g) / min.

(3) Test Results FIG. 2 is a graph showing the relationship between the temperature of each part of the tire case and the vulcanization time in the vulcanization process of the example. FIG. 3 is a graph showing the relationship between the temperature of each part of the tire case and the vulcanization time in the vulcanization process of the comparative example. 2 and 3, the vertical axis represents temperature, the horizontal axis represents vulcanization time, and the thick vertical line in the center represents the PCI process start point.

  As shown in FIG. 2, in the case of the example, the temperature rapidly decreases after moving to the PCI process, and after 10 minutes from the start of the PCI process, the temperature of any part is less than 100 ° C., and the thermal contraction of the ply does not occur. I was able to confirm.

  On the other hand, in the case of the comparative example, it was confirmed from FIG. 3 that the tire case in the buttress position was 100 ° C. or higher and heat shrinkage occurred even after 10 minutes or more from the PCI process start time.

  In order to suppress the thermal shrinkage of the ply, it is necessary to quickly cool to 100 ° C. or less after the vulcanization and after the transition to the PCI process, the thermal shrinkage does not occur. It was confirmed that the comparative example was not satisfied.

(4) Tire Performance Evaluation (a) Evaluation Method RFV and RRO were measured for tires of Examples and Comparative Examples using a tire FV machine, and an average value (Ave) and a standard deviation (σ) were determined for each.

(B) Evaluation results Table 1 shows the evaluation results of Examples and Comparative Examples.

  From Table 1, it was found that in the example, Ave and σ were reduced in both RFV and RRO as compared with the comparative example, and the uniformity was improved.

  While the present invention has been described based on the embodiments, the present invention is not limited to the above embodiments. Various modifications can be made to the above-described embodiments within the same and equivalent scope as the present invention.

1 Post cure inflator (PCI)
11 Support shaft 12 Upper rim 13 Lower rim 14 Sprayer 14a Spray hole 15 Air vent T Tire

Claims (2)

A post-cure inflator that includes a pair of upper and lower rims that fits into a bead portion of a tire and supports the tire, and that performs pressure cooling in a state in which the tire is filled with internal pressure,
A post-cure inflator characterized in that a sprayer for spraying a cooling medium into a tire and an air vent for exhausting air in the tire are provided on the rim. A method for cooling a post-vulcanized tire that cools a high-temperature tire immediately after vulcanization using the post-cure inflator according to claim 1,
Cooling the tire from the inside by spraying a cooling medium into the tire from the sprayer;
By exhausting the air in the tire through the air vent, an increase in the internal pressure of the tire due to evaporation of the sprayed cooling medium is suppressed and the internal pressure of the tire is kept constant. Cooling method.

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