JP2607755B2 - Method of manufacturing bent rubber products - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for producing a rubber product having a curved shape such as an arc or a polygonal frame.

[0002]

2. Description of the Related Art Conventionally, arc seals are used for joint seals of large-diameter pipes, pot packing for electric rice cookers and gas cookers, steam packing for pressure cookers, lid packing for jar pots, and airtight materials for round windows. Alternatively, a rubber product having a curved shape such as a polygonal frame shape is used.

[0003] Since these rubber products often have relatively complicated cross-sectional shapes, they are generally manufactured by compression molding or injection molding. However, in these methods, there are many steps that require manual operations such as removing a rubber product from a mold every time molding is performed and removing burrs of the mold and the rubber product, and the number of molds to be removed is limited. The production efficiency was very low, and the product cost was also high.

[0004] In general, when the cross-sectional shape is simple such as a circular or square shape such as packing of food containers made of resin, a long rubber extruded product continuously extruded by an extruder is used as a linear extruded product. It can also be manufactured by a method of vulcanizing as it is, cutting this, and bonding both ends.

[0005] However, when a rubber product having a complicated cross-sectional shape such as the above-mentioned pot packing is formed, this method forcibly bends a vulcanized linear rubber product. Are compressed and the outer part is stretched. As a result, as shown in FIG. 4, distortion occurs in the overall shape, such as the inner portion 2 of the bent rubber product 1 waving or the outer portion falling inward, and a product satisfying the airtight performance is obtained. I can't.

Moreover, a rubber extruded product continuously extruded from an extruder is straight, and even if it is vulcanized as it is on a flat belt or the like, a vulcanized product having a complicated cross-sectional shape is vulcanized. Plastic deformation occurs before completion and the correct shape cannot be maintained. On the other hand, there is a method in which a long rubber extruded product is spirally wound around a vulcanizing basin or vulcanizing dish and vulcanized.However, the portion wound inside the spiral has a small radius of curvature, and conversely, Since the radius of curvature of the wound portion becomes large, the radius of curvature of the rubber product having a curved shape cannot be controlled.

In order to solve these problems, a linear long rubber extruded product is cut in advance and inserted into a curved mandrel or set on a receiving core to regulate it to a desired bending state. A method of performing curling vulcanization in a state was also studied.

[0008] However, this curling vulcanization method has the disadvantage that the efficiency is inferior because manual work is performed one by one, and that defective products and material loss increase, thereby increasing the product cost. Further, in the case of a material having a low viscosity of unvulcanized rubber such as silicone rubber, the cross-sectional shape is easily deformed or the cross-sectional dimension is easily changed during manual work. I couldn't do it.

[0009]

SUMMARY OF THE INVENTION In view of the above-mentioned circumstances, the present invention has a curved rubber product which has a complicated cross-sectional shape forming a predetermined uneven shape, and is wholly or partially curved at a predetermined curvature. Is to provide a method for efficiently producing the same.

[0010]

In order to achieve the above-mentioned object, the present invention provides a method for manufacturing a bent rubber product, wherein the cross section of the outer periphery has an uneven shape substantially along one side surface of the rubber extruded product. A rotating disk whose surface is curved in whole or in part at the required curvature is provided in the vulcanizing furnace, and the unvulcanized long rubber extruded product extruded into an uneven cross section is continuously placed in the vulcanizing furnace. Along the longitudinal direction, the long rubber extruded product is wound around one side of the extruded piece so as to be in contact with the outer peripheral surface of the turntable. After the vulcanization, the obtained long rubber product having a curved shape is cut, and both ends are bonded to form an arc or polygonal frame.

In the present invention, the curved shape includes both an arc shape that is entirely curved and a polygonal frame shape that is partially curved. Therefore, the curvature of the outer peripheral surface of the turntable is entirely reduced. In addition to the case where the curve is curved at a fixed curvature, the curvature may be partially changed, or a continuous wave shape in which the direction of the curve is alternately changed may be used.

[0012]

According to the present invention, as shown in FIG. 1, which is a specific example of an apparatus for performing continuous curling vulcanization, an unvulcanized and long rubber extruded product continuously extruded from an extruder 7. 3 is cut into the vulcanizing furnace 4 as it is without cutting, and the longitudinal direction of the rotating disk 5 is rotated along the whole or partially curved outer peripheral surface 6 of the rotating disk 5 rotating in the vulcanizing furnace 4. With the rotation of 5, it is moved while being wound around the outer peripheral surface 6.

The outer peripheral surface 6 of the rotating disk 5 is entirely or partially curved in advance at a required curvature, and at the same time, as shown in FIG. 2, one side of a rubber extruded product 3 having a predetermined sectional shape. Is formed in advance in an uneven shape substantially along one side surface so that the can be easily fitted. Therefore, rubber extruded product 3
The cross-sectional shape of the extruded rubber product 3 does not collapse while the rubber product 1 moves while being vulcanized, so that the obtained rubber product 1 can maintain the desired cross-sectional shape and the correct cross-sectional shape at the same time.

In this manner, the unvulcanized rubber extrudate 3
The vulcanization proceeds by the heat of the vulcanization furnace 4 while moving while rotating together with the turntable 5 in the vulcanization furnace 4. Vulcanizing furnace 4
By adjusting the temperature of the rotating disk 5 and the rotating speed of the rotating disk 5, the unvulcanized rubber extruded product 3 together with the rotating disk 5 is almost 3/4.
Vulcanization is completed before rotating. It is also effective to heat the turntable 5 itself in order to accelerate the progress of vulcanization and obtain a uniform vulcanized state.

According to the above method, the long rubber extruded product 3
Are successively vulcanized along the curved outer peripheral surface 6 of the turntable 5, so that the obtained long rubber product 1 has the same curved state as the outer peripheral surface 6 of the turntable 5 while maintaining the cross-sectional shape. Knitting, that is, vulcanization molding. Accordingly, the vulcanized rubber product 1 is continuously taken out of the vulcanizing furnace 4 to the outside, cut into a predetermined length, and bonded at both ends. As shown in (1), a rubber product having a correct bent shape without partial waving or overall distortion and having a predetermined cross-sectional shape can be obtained.

[0016]

EXAMPLE An entire outer peripheral surface of a steel disk having a diameter of 240 mm was processed into an uneven shape substantially along the inner surface of a pot packing of an electric jar rice cooker, and this was set in a hot air vulcanizing furnace as a rotary disk. The temperature in the hot air vulcanizing furnace was set at 250 ° C., and the temperature of the turntable was maintained at about 250 ° C.

On the other hand, an unvulcanized silicone rubber extrusion compounding composition is continuously extruded from a die of an extruder into a cross-sectional shape of a pot packing, and the extruded rubber product is inserted through a hole provided in a side surface of a vulcanizing furnace. And one side was placed on the outer peripheral surface of the turntable and fitted, and sequentially moved while rotating with the turntable rotating at 4 rpm.

The rubber extruded product was peeled off from the turntable at the position where it was rotated by 3/4, and taken out from another hole provided on the side of the vulcanizing furnace. The obtained long rubber product was used for pot packing. 240mm diameter while maintaining correct cross-sectional shape
It was curved and formed into a circular arc shape.

The long curved rubber product was cut into a predetermined length, and both ends thereof were adhered to produce an arc-shaped electric jar rice cooker pot packing having a diameter of 240 mm. This pot packing had no distortion or undulation as a whole and could be attached to an electric jar rice cooker to obtain excellent airtightness.

[0020]

According to the present invention, a long rubber extruded product linearly extruded with a predetermined cross-sectional shape is continuously kneaded and vulcanized by being attached to a turntable. While maintaining the cross-sectional shape, it can be fully or partially curved at the required curvature, so simply cutting it and bonding both ends can easily produce rubber products with the desired cross-sectional shape and bent shape And can be manufactured efficiently.

Accordingly, pot packing for electric kettles and gas cookers, lid packing for jar pots, which require a curved shape such as an arc shape or a polygonal frame shape and a complicated sectional shape,
Rubber products such as airtight materials for round windows can be produced easily and efficiently at low cost without causing collapse of the cross-sectional shape or distortion of the overall shape, and extremely few defective products and material loss. You can do it.

[Brief description of the drawings]

FIG. 1 is a schematic side view showing a specific example of an apparatus for performing curling vulcanization according to the method of the present invention.

FIG. 2 is a cross-sectional view of an unvulcanized long rubber extruded product supported on an outer peripheral surface of a rotary disk of the above device.

FIG. 3 is a perspective view of a part of a bent rubber product manufactured by the method of the present invention.

FIG. 4 is a partial perspective view showing a state in which a linear rubber product is forcibly bent.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Rubber product 2 Inner part 3 Rubber extruded product 4 Vulcanizing furnace 5 Rotating disk 6 Outer peripheral surface 7 Extruder

──────────────────────────────────────────────────続 き Continued on the front page (51) Int.Cl. ⁶ Identification code Agency reference number FI Technical display location B29L 31:26

Claims (1)

(57) [Claims] 1. A vulcanizing furnace having a rotating disk whose outer cross section has an irregular shape substantially along one side of a rubber extruded product and whose outer peripheral surface is wholly or partially curved at a required curvature. An unvulcanized long rubber extruded product extruded into an uneven shape is continuously guided into a vulcanizing furnace so that one side of the long rubber extruded product is in contact with the outer peripheral surface of the turntable along the longitudinal direction. Winding,
After vulcanizing to the curved shape of the outer surface of the rotating plate while maintaining the uneven shape of the cross section while rotating with the rotating plate, cut the obtained long rubber product of the curved shape, and glue both ends to form an arc or A method for producing a bent rubber product, wherein the rubber product has a polygonal frame shape.