JP6033659B2 - Sliding surface forming method in sliding portion of tire vulcanizing container - Google Patents

Description

  The present invention relates to a method for forming a sliding surface in a sliding portion of a tire vulcanizing container used in a vulcanizing process of a green tire.

  Pneumatic tires are generally manufactured by setting a molded green tire in a vulcanizing device and vulcanizing it by heating under pressure (for example, Patent Document 1).

  This vulcanizing apparatus includes a vulcanization mold (hereinafter also referred to as “mold”), a tire vulcanization container (hereinafter also simply referred to as “container”) for storing the vulcanization mold, and a vulcanized green tire. It is equipped with a bladder that presses against the vulcanizing mold.

  As shown in FIG. 3, the container includes an upper mold plate 6, a lower mold plate 7, a sector shoe 9, and an actuator 10. The sector shoe 9 is divided in the circumferential direction (9 divisions in FIG. 3).

  Next, the vulcanizing apparatus will be described with reference to FIG. In FIG. 4, 1 is a vulcanizer and 5 is a mold. The mold 5 includes upper and lower side molds 2 and 3 and a tread segment 4 (hereinafter also simply referred to as “segment”) divided in the circumferential direction, and is stored in the container described above. In addition, 16 is a sector guide part, 17 is a guide key, 18 is a metal plate (sector receiving) of a lower mold plate, and T is a tire.

  The container is connected to the upper and lower platen plates 12U and 12L provided on the press via the actuator 10 and the lifting platform 13. As the elevator 13 is raised and lowered, the actuator 10 raises and lowers the sector guide 16 along the guide key 17, and accordingly, the segment 4 stored in the sector shoe 9 opens and closes, and the upper side The mold 2 is raised and lowered.

  For vulcanization of the tire, after the tire T (green tire) is set in the mold 5, as shown in FIG. 4A, the elevator 13 heated to a high temperature is lowered and the container and the vulcanizing mold 5 are moved. Is closed, and a bladder (not shown) is inflated with a high-temperature heating medium inside the green tire T, and the green tire T is pressed against the vulcanizing mold 5 to heat and press both sides of the green tire T. Is called.

  After the vulcanization is completed, the heating medium is discharged from the bladder to stop the pressurization, and as shown in FIG. 4B, the elevator 13 is raised to open the container and the vulcanization mold 5. The tire T (vulcanized tire) is taken out.

  In this way, in the tire vulcanization process, the container is moved up and down and opened / closed. At that time, if the container does not slide uniformly, the vulcanization mold cannot be uniformly closed. There is a gap in If vulcanization is performed in such a state, the rubber flows into the generated gap, and there is a risk that a tire with a protruding rubber burr (over spew: OV / SP) may be produced. Specifically, as shown in FIG. 5, when there is a gap between the segment and the segment, the radial OV / SP is obtained, and when there is a gap between the segment and the side mold, the circumferential OV / SP is obtained. Arise.

  A tire in which OV / SP is generated not only causes poor appearance but also generates abnormal noise and vibration. For this reason, the generated OV / SP is cut by an operator's manual work before shipping, but an extra labor cost is generated, resulting in an increase in cost. Further, if OV / SP is mixed into the vulcanized tire, it becomes scrap as a foreign matter (FM) mixed tire, so that a cost for scrap processing is generated, and this also causes an increase in cost.

  Therefore, in order to achieve uniform sliding of the container, conventionally, grease has been generally applied to the sliding surface of the container as a lubricant. Thereby, the pressure from a press can be uniformly transmitted to a mold, and generation | occurrence | production of OV / SP can be suppressed. Also, wear of the container can be prevented.

  Specifically, by applying grease to the sliding surface of the container, as shown by the arrows in FIG. 6 (a), the container can slide uniformly to transmit the pressure from the press to the mold uniformly. Therefore, there is no gap on the mating surface of the mold that is in the closed state, and generation of OV / SP can be suppressed.

JP 2011-46069 A

  However, in the past, inexpensive grease containing molybdenum disulfide, which is generally used, has a melting point of 190 ° C., which is slightly higher than the normal vulcanization temperature of 183 ° C. I can't say. Also, the amount of evaporation at high temperatures is large and the amount of evaporation loss is large. For this reason, the sliding performance cannot be maintained for a long time, and the sustainability as a lubricant is low.

  If the sliding performance decreases with the passage of time, the container will not slide uniformly as indicated by the arrow in FIG. 6B, and the pressure from the press cannot be uniformly transmitted to the mold. A gap is generated on the mating surface of the mold in the state, and OV / SP is generated.

  Therefore, the amount of grease required for uniform sliding has been ensured by increasing the amount of grease containing molybdenum disulfide per application, and further recoating it halfway. However, in this case, a new problem has arisen that the residue derived from grease and the floating dust are adsorbed to generate dirt, and the dirt is mixed into the tire as foreign matter (FM).

  For this reason, there has been a demand for a method capable of sliding the container uniformly over a long period of time using grease having higher heat resistance and longer-lasting performance.

  From such a viewpoint, a method of attaching a metal lubricant sheet to a sliding surface instead of grease has been proposed. However, when this method is adopted, this lubricant sheet must be attached to all sliding surfaces, and it must be replaced when the lubricant sheet is worn out. There is a problem that it takes.

  Therefore, the present invention provides a sliding portion of a tire vulcanizing container used in a vulcanizing process of a green tire, which can slide the container uniformly over a long period of time without incurring costs and time. It is an object to provide a surface forming method.

The present invention has been made on the basis of the first to third techniques described below, and the first technique related to the present invention is:
A sliding surface forming method in a sliding portion of a tire vulcanizing container used in a vulcanizing process of a green tire,
The sliding surface forming method is characterized in that the sliding surface is formed by applying grease containing a fluorine component to the sliding surface of the sliding portion.

The second technique related to the present invention is:
The sliding surface forming method according to the first technique , wherein the grease is a mixture of a fluorine-based synthetic oil as a base oil and polytetrafluoroethylene as a thickener.

The third technique related to the present invention is:
The sliding surface according to the second technique , wherein the grease is a mixture of 65 to 75% by mass and 25 to 35% by mass of the mixing ratio of the fluorinated synthetic oil and polytetrafluoroethylene, respectively. It is a forming method.

And invention of Claim 1 is,
A sliding surface forming method in a sliding portion of a tire vulcanizing container used in a vulcanizing process of a green tire,
The sliding portion is a sliding portion formed on the inner surface of the actuator, the back surface of the sector shoe, on the upper metal plate, on the lower metal plate, on the upper portion of the sector shoe,
Applying grease containing a fluorine component to the sliding surface of the sliding portion to form a sliding surface,
The grease is a mixture of fluorine-based synthetic oil as a base oil and polytetrafluoroethylene as a thickener,
Furthermore, the said grease is a sliding surface formation method characterized by the mixture ratios of the said fluorine-type synthetic oil and polytetrafluoroethylene being 65 to 75 mass% and 25 to 35 mass%, respectively.

  According to the present invention, the sliding portion of the tire vulcanization container used in the vulcanization process of the green tire can slide the container uniformly over a long period of time without incurring costs and time. A moving surface forming method can be provided.

It is a perspective view of the application | coating location of the grease in one embodiment of this invention. It is a figure which shows the evaporation residual amount test result of various grease containing the grease used by one embodiment of this invention. It is a perspective view explaining the structure of the tire vulcanization container used in the vulcanization process of a general green tire. It is sectional drawing which shows typically the general structure of a vulcanizer. It is a perspective view which shows an example of generation | occurrence | production of OV / SP. It is a figure explaining a grease effect.

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

1. Grease In the present embodiment, grease containing a fluorine component is used.

  Grease containing a fluorine component is excellent in heat resistance (250 ° C.). Further, since the evaporation loss is stable even at high temperatures, the residue is not generated. For this reason, when such a sliding surface coated with grease is formed, the sliding performance can be maintained for a long period of time, and the high sustaining performance is exhibited as a lubricant, making the container uniform over a long period of time. The vulcanization can be performed without generating OV / SP.

  In addition, grease containing a fluorine component is preferable because it has little influence on metal and rubber.

  As the grease containing such a fluorine component, a mixture of fluorine-based synthetic oil as a base oil and polytetrafluoroethylene as a thickener is preferable. Fluorine-based synthetic oils and polytetrafluoroethylene are excellent in heat resistance and stability, and therefore can be preferably used as a lubricant having particularly high sustainability.

  The mixing ratio of the fluorinated synthetic oil and the polytetrafluoroethylene is preferably 65 to 75% by mass and 25 to 35% by mass, respectively, and by setting such a ratio, it is easily adjusted to a viscosity preferable as a lubricant. can do.

2. Grease application location, application method (1) Application location Next, the grease application location will be described. In this embodiment, as shown in FIG. 1, the inner surface of the actuator (FIG. 1 (a)), the rear surface of the sector shoe (FIG. 1 (b)), the upper metal plate and the lower metal plate (FIG. 1). (C)) or the like is applied with grease. Moreover, it may be applied to the upper part of the sector shoe.

(2) Application method In the present embodiment, the grease is basically the same as in the past, after removing the dirt of the container, after removing a small amount of grease with a brush, It is applied by spreading thinly. Thus, since it can apply | coat simply, unlike the case where the method of attaching a metal lubricant sheet | seat mentioned above to a sliding surface is applied, cost and time are not taken.

  The amount of coating is about 5 to 10 g per surface in the case of application on the lower metal of the lower plate, and about 20 g per surface in the case of application to other locations.

  As for the frequency of application, it is preferable that the lower plate plate metal is applied every time the vulcanizing mold is incorporated, and the inner surface of the actuator and the upper and rear surfaces of the sector shoe are applied every month.

  Next, based on an Example, this invention is demonstrated more concretely.

1. Evaluation of sustainability by residual evaporation test First, the sustainability of grease was evaluated by residual evaporation test.

  As an example, a commercially available grease (manufactured by Daizo, trade name: Tribon LCO) in which 65 to 75% by mass of the above-described fluorine-based synthetic oil and 25 to 35% by mass of polytetrafluoroethylene were mixed was prepared and compared. As an example, a grease containing conventional molybdenum disulfide was prepared.

  Each grease was applied to a test piece of 100 mm × 50 mm × 1 mm and then left in an atmosphere of 190 ° C. to determine the remaining evaporation (%) with the passage of days.

  The results are shown in FIG. In FIG. 2, the vertical axis represents the remaining amount of grease (%), and the horizontal axis represents the number of days elapsed (days).

  As shown in FIG. 2, in the grease of the comparative example, the remaining amount of grease decreased to 74.2% after 14 days as the cleaning cycle. On the other hand, in the grease of the example, the remaining amount of grease is as high as 88.7% even after 14 days, and even after passing up to 35 days, the remaining amount of grease is sufficiently high as 81.2%. It can be seen that the lubrication effect has excellent durability.

2. Next, a vulcanization experiment was performed on the following four sizes of tires using the above tribon LCO as the grease.
(I) "155 / 65R13"
(B) “175 / 65R14”
(C) "175 / 60R16"
(D) "155 / 65R13"

  Specifically, vulcanization was performed for 3 to 17 days using a total of 10 vulcanizers, and the occurrence of OV / SP was observed.

  As a result, generation of OV / SP was not recognized for all sizes, and it was confirmed that the grease maintained sufficient sliding performance. In addition, no press trouble due to grease occurred.

  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 Vulcanizer 2, 3 Side mold 4 Tread segment (segment)
5 Vulcanizing mold (mold)
6 Upper mold plate 7 Lower mold plate 9 Sector shoe 10 Actuator 12U, 12L Platen plate 13 Lifting platform 16 Sector guide 17 Guide key 18 Debametal T of lower plate T Green tire (tire)

Claims (1)

A sliding surface forming method in a sliding portion of a tire vulcanizing container used in a vulcanizing process of a green tire,
The sliding portion is a sliding portion formed on the inner surface of the actuator, the back surface of the sector shoe, on the upper metal plate, on the lower metal plate, on the upper portion of the sector shoe,
Applying grease containing a fluorine component to the sliding surface of the sliding portion to form a sliding surface ,
The grease is a mixture of fluorine-based synthetic oil as a base oil and polytetrafluoroethylene as a thickener,
Furthermore, the said grease is a mixture whose mixing ratio of the said fluorine-type synthetic oil and polytetrafluoroethylene is 65-75 mass% and 25-35 mass%, respectively, The sliding surface formation method characterized by the above-mentioned.

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