JPH0249206B2 - DAIKEITETSUSHINIRIGOMUPATSUKINGUNOSEIZOHOHO - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION (Technical Field of the Invention) The present invention relates to a method of manufacturing a rubber packing such as a large-diameter core O-ring.

(Technical Background of the Invention) Conventionally, in order to manufacture rubber packing in which a ring-shaped iron core with a large diameter of 1,500 to 2,200 mmφ is embedded, the iron core is covered with an unvulcanized rubber body that is press-formed into a substantially ring shape in advance. However, a method was used in which the material was loaded into a mold, heated and pressurized, and vulcanized.

Additionally, when covering the core with the unvulcanized rubber body, aluminum pieces were placed in advance at positions dividing the core into 16 sections to prevent eccentricity of the core.

(Problems with the Background Art) However, with these methods, it is difficult to hold the iron core in the center of the rubber body for the reasons described below, and it has not been possible to manufacture a rubber packing containing an iron core without eccentricity.

In other words, (1) Since large-diameter cores are manufactured by bending steel bars, it is difficult to process each part into a nearly perfect circle with the same diameter, and the pressure during vulcanization may damage the core itself. is more easily deformed.

(2) Since the amount of unvulcanized rubber coated around the iron core cannot be made completely constant over the entire circumference, when the rubber is plasticized during the vulcanization process, the internal pressure of each part of the rubber becomes uneven and the pressure increases. It is easy for the iron core to move to the lower side.

(3) It is difficult to apply uniform pressure to the entire mold using a large pressurizing device.

There was a problem that eccentricity of the iron core was likely to occur due to the following reasons.

(Objective of the Invention) An object of the present invention is to provide a method for solving the above-mentioned problems and manufacturing a large-diameter iron-core rubber packing with less eccentricity.

(Summary of the invention) The present invention provides a semi-vulcanized rubber layer at a predetermined position around a large ring-shaped iron core, and then covers the outside with a packing body made of unvulcanized rubber. The present invention relates to a method for manufacturing a rubber packing containing a large diameter iron core, which is characterized by loading the packing into a cavity of a mold, heating it under pressure, and vulcanizing it integrally.

(Embodiments of the Invention) The present invention will be described below based on embodiments shown in the drawings.

In the present invention, first, a pre-molded layer 2 is intermittently placed on a ring-shaped iron core 1, which is approximately circular in cross section with a cross section of 13 mmφ and 1500 mmφ obtained by pressurization using a conventional method, at positions where the circumference is divided into 8 to 16 equal parts. will be established. This pre-molded layer 2 is vulcanized to about 70% of normal vulcanization. Further, the pre-molded layer 2 is provided so as to cover the iron core 1, but has an outer diameter slightly smaller than that of the molded rubber portion.

Next, after roughening the surface of the pre-mold layer 2 and cleaning it with a solvent, an adhesive is applied to the exposed surface of the iron 1 and the surface of the pre-mold layer 2.

Next, a rubber body 3 made of unvulcanized rubber that has been previously press-molded into a predetermined shape is coated around the core 1 including the pre-molded layer 2, and the entire body is placed in a mold (not shown) kept at room temperature. ) into the cavity.

Here, before covering the rubber body 3, a tape 4 made of unvulcanized rubber is wrapped around the outside of the pre-mold layer 2 and the part where this layer and the rubber body 3 are joined.
After loading the whole into the mold, pressure is applied to the mold to determine whether there is too much or insufficient rubber in the cavity.
It is desirable to adjust this with a wound layer of unvulcanized rubber. Thereafter, the entire mold is heated to a fluidization temperature while applying pressure, and the rubber body 3, pre-mold layer 2, and unvulcanized rubber tape wound layer are integrally vulcanized and molded.

With this configuration, for example, the following effects occur. In other words, since the density of the rubber inside the mold cannot be kept constant, when it is plasticized during the vulcanization process, the pressure inside the mold becomes unbalanced, and the iron core tends to move to the side with lower pressure. , a pre-molded layer 2 that is harder than the rubber body 3
The presence of the iron core suppresses its movement, thus preventing eccentricity of the iron core.

(Effects of the Invention) According to the method of the present invention configured as described above, a relatively hard rubber pre-mold layer is provided in advance at multiple locations around the iron core, so that unevenness of the iron core during vulcanization can be prevented. can be minimized, and rubber packing with an iron core without eccentricity can be manufactured with a high yield.

[Brief explanation of drawings]

The drawing is a sectional view showing an embodiment of the method of the present invention. 1... Iron core, 2... Rubber pre-mold layer, 3...
...Rubber body, 4...Unvulcanized rubber tape winding layer.

Claims (1)

[Claims] 1 A pre-molded layer made of semi-vulcanized rubber is fixed at multiple locations around the large-diameter ring-shaped core,
A rubber packing with a large-diameter iron core is characterized in that the outside is coated with a main body of unvulcanized rubber molded into an approximately predetermined shape, and then the entire body is loaded into a mold and heated under pressure to be vulcanized as a unit. manufacturing method.