JPS61202829A - Manufacture of bellows - Google Patents

Abstract

PURPOSE:To contrive to endow heat resistance and incombustibility, by a method wherein after woven fabric of aromatic polyamide fiber has been made to impregnate with fluororesin and dried at a specific temperature, the same is processed into a cylindrical member in which rings are arranged and the fluororesin is made to polymerize through heating. CONSTITUTION:As for woven fabric 1, aromatic polyamide fiber is used, which is impregnated with an aqueous suspension of fluororesin 2 by immersing the same into the aqueous suspension and made into a dried article 1 by making the same dry at the temperature of 200-250 deg.C. A cylindrical member 3 is formed by applying sewing processing to the dried article 1A. In this instance, finished yarn which is obtained by making a glass fiber impregnate with fluororesin or heat-resistant yarn 5 of an aromatic polyamide fiber is used. Rings 6-6 are arranged within the cylindrical member 3 obtained by turning a part 4 sewed up inside. The rings 6.6 are composed of a metallic wire such as stainless steel and the diameters of them are about the same as the inside diameter of the cylindrical member 3. Then the cylindrical member 3 is shifted to the heating furnace and heated at 300-350 deg.C. As the woven fabric 1 becomes of a thin to be obtained by impregnating with polymerized fluororesin, the same is the thin possessing heat resistance and function of flexible bellows.

Description

[Detailed description of the invention] (Industrial application field) This invention relates to a method for manufacturing bellows.

(Prior art) Conventionally, ordinary bellows used for links of mechanical devices, etc., have no heat resistance because the bellows part is made of rubber, cloth, or synthetic resin. There was a problem with burning due to such things.

(Problems to be Solved by the Invention) However, the present invention is an attempt to solve the above-mentioned problems of the conventional art. The purpose of the present invention is to provide a method for manufacturing bellows that obtains the following.

(Means for Solving the Problems) Therefore, in order to solve the above-mentioned problems, the means of the first invention impregnates a woven fabric of aromatic polyamide lI fibers with fluorine oil and After drying at 250°C, it is processed into a cylindrical shape to form a cylinder, and a metal ring with approximately the same diameter as the cylinder is placed inside the cylinder. It is heated at ℃ to cause the fluororesin to undergo a polymerization reaction.

The means of the second invention is to sew a woven fabric made of aromatic polyamide into a cylindrical shape to form a cylindrical body, impregnate the cylindrical body with a fluororesin, and heat the woven fabric at about 200 to 250°C. A dry cylindrical body is formed, and a metal ring with approximately the same diameter as the cylindrical body is arranged inside the cylindrical body, and the cylindrical body with the rings arranged is approximately 30
The fluororesin is polymerized by heating at 0 to 350°C.

The aromatic polyamide m, m woven fabric is, for example, a heat-resistant W called "-Nex" (manufactured by Tijin, trade name).
HH is used. The fluororesin is a polymer containing fluorine such as tetrafluoroethylene resin, tetrafluoroethylene/hexafluoropropylene copolymer resin, trifluorochloroethylene resin, vinylidene fluoride resin, vinyl fluoride resin, etc., and is thermally stable. Materials with high properties and chemical resistance are used. The woven fabric is impregnated with an aqueous suspension of the fluororesin by coating, spraying, or the like. Woven fabric impregnated with fluororesin does not polymerize and harden the fluororesin.
It is considered as a dry product at 250°C.

Dried products are cut to the specified size as needed and placed in a cylindrical shape.
Processed from a. The rings made of gold may be a plurality of rings having the same diameter as the cylindrical body, arranged at predetermined intervals, or a spiral ring. Note that a support may be used when placing the ring on the cylindrical body, and may be removed after processing. The cylindrical body with the rings placed thereon is heated to polymerize the fluororesin impregnated into the woven fabric.

(Function) The fluororesin impregnated into the woven fabric is polymerized and cured by heating at 300 to 350°C. That is, when the temperature exceeds 300°C, the dimensions gradually change and shrink, and at 350°C, the resin shrinks by about 10% and the fluororesin polymerizes and hardens. Therefore, the ring portion of the cylinder is supported by the ring and becomes a portion of a predetermined diameter, and the portion between the rings becomes a small diameter portion due to contraction, forming a bellows.

(Example) Next, one embodiment of the present invention will be described with reference to the drawings.

The woven fabric 1 shown in Fig. 1 is commercially available "Conex" (trade name of aromatic polyamide I! woven fabric manufactured by Tijin KKlJ).
is used. The woven fabric 1 is soaked in an aqueous suspension of tetrafluoroethylene resin to be impregnated with the tetrafluoroethylene resin WR2.

The woven fabric 1 impregnated with the tetrafluoroethylene resin 2 is taken out from the suspension, transferred to a drying oven, and dried at a temperature of 200 to 250°C to obtain a dried product 1A.

The dried product 1A of the woven fabric 1 is cut into a predetermined size if necessary and sewn to form the cylinder 3. For the sewing process, a heat-resistant thread 5 such as processed thread made of glass mm impregnated with a fluororesin such as tetrafluoroethylene resin or thread made of aromatic polyamide all is used.

After the cylinder body 3 having the seamed portion 4 on the outside is folded back so that the seamed portion 4 is on the inside (see Fig. 4),
, the rings 6 to 6 are arranged inside the cylinder 3. The rings 6 to 6 are made of metal wire such as stainless steel and have approximately the same diameter as the inner diameter of the cylinder 3, are arranged at predetermined intervals, and are supported by supports (not shown).

Thereafter, the cylindrical body 3 with the rings 6 to 6 arranged thereon is transferred to a heating furnace and the temperature is increased one after another. Shrinkage changes were observed in dimensions at a furnace temperature of 300°C. A shrinkage of about 2% was observed at 310°C. At this point, remove and remove the supports for rings 6 to 6 and check that there is no displacement of rings 6 to 6.
Further heating caused about 3% shrinkage at 320°C, about 5% shrinkage at 330°C, and 10% shrinkage at 350°C. Cylindrical body 3 becomes ring 6 due to contraction.
The bellows 7 was formed by having large diameter portions 1B to 1B in close contact with the rings 6 to 6, and a small diameter portion having a smaller diameter than the rings 6 to 6 in the inter-ring portion. Since the tetrafluoroethylene resin 2 is polymerized by heating at 350° C., no further temperature increase is required.

Since the woven fabric 1 is impregnated with polymerized tetrafluoroethylene resin, it has heat resistance and functions as a bellows that can be freely expanded and contracted.

In the above-mentioned example, after the woven fabric 1 was treated with the fluororesin 2, the I
In this case, the cylindrical body is made by sewing a woven fabric into a cylindrical shape, impregnating it with fluorine mt, and drying it at about 200 to 250°C to form a dry cylinder. It is also possible to make a bellows by placing a ring thereon and then performing the same steps as in the above embodiment.

Further, in the above embodiment, the circular rings 6 to 6 are arranged inside the cylinder 3 to form the bellows 7 with a circular cross section. However, the rings arranged inside the cylinder are not limited to circular ones, and may be triangular, square or polygonal. It is possible to form a bellows with a triangular, quadrangular or polygonal cross section.

(Effect of the invention) According to the double invention, since the woven fabric of the cylinder contracts when heated, the ring portion of the woven cylinder fabric is in close contact with the ring, and the portion between the rings of the woven cylinder fabric has a small diameter. As the fluororesin impregnated into the woven fabric polymerizes and hardens, the woven fabric becomes a fluororesin-treated product, and due to the physical properties of the fluororesin, it has excellent heat resistance and chemical resistance, and is nonflammable. be.

Since this fluororesin processed body has appropriate rigidity, it has an elastic force that can be restored against compression of the bellows, which is convenient. According to both inventions, a good bellows made of aromatic polyamide IIN treated with fluororesin can be obtained. Note that this bellows is well suited for use in the arm portion of a working robot or the link portion of a mechanical device.

[Brief explanation of drawings]

The figure shows one embodiment of the present invention! Fig. 1 shows the manufacturing process of aromatic polyamide l! Figure M2 is an enlarged cross-sectional view showing the woven fabric impregnated with fluororesin and dried; Figure 3 is a perspective view of a sewn cylinder;
Figure 4 is a perspective view of the cylinder with the seam inside, Figure 5
The figure is a front view of the ring, FIG. 6 is a partially cutaway perspective view of the cylindrical body in which the ring is placed, and FIG. 7 is a front view of the bellows. 1... Woven fabric 1A... Dry product 1B... Large diameter section 1C... Small diameter section 2... Tetrafluoroethylene resin 3... Cylindrical body 4... Sewing section 6 ... Ring Gua ... Bellows Applicant Nippon Polymer Co., Ltd. Agent Patent Attorney Hidehiko Okada (2 others) A

Claims (2)

[Claims] (1) A woven fabric of aromatic polyamide fibers is impregnated with fluororesin, dried at about 200 to 250°C, and then sewn into a cylindrical shape to form a cylinder. A method for producing a bellows, which comprises arranging metal rings having approximately the same diameter, and heating the cylindrical body on which the rings are arranged at about 300 to 350°C to cause a polymerization reaction of a fluororesin. (2) A woven fabric of aromatic polyamide fiber is sewn into a cylindrical shape to form a cylindrical body, the cylindrical body is impregnated with a fluororesin, and this is dried at about 200 to 250°C to form a cylindrical body; A metal ring is placed inside the cylinder with approximately the same diameter as the cylinder,
A method for manufacturing a bellows, which comprises heating a cylinder arranged in rings at about 300 to 350°C to polymerize a fluororesin.