JPH0429691A - Method for vulcanizing double pipe - Google Patents

Abstract

PURPOSE:To obtain a double pipe of specified length immediately after vulcanization by vulcanizing an elastic material to adhesively attach an outer cylinder between itself and the elastic material in a condition that inner and outer cylinder tubes are fixed by brining the other end of the inner cylinder tube into contact with a stopper device. CONSTITUTION:A built double pipe 7 is received between upper and lower molds 3, 4 of a hot press to close the upper and lower molds 3, 4 and fixed by extruding one end part of an inner cylinder 7a by an extruding device 5 in a reverse direction to the press-fit direction of the inner cylinder and by bringing the other end part into contact with a stopper jig 6. In this way, a total length of the double pipe 7 is restricted in a specified range by the stopper jig 6 while restoring the elastic deformation generated in an elastic material 7b. Next, the upper and lower molds 3, 4 are heated under this condition, and the elastic material 7b and an outer cylinder 7c are adhesively attached by vulcanizing the elastic material 7b. In the case of relaxing residual distortion in the elastic material by heat during vulcanization, a movement of the inner cylinder 7a and a position of the outer cylinder 7c are restricted respectively by the stopper jig 6 and outer cylinder stoppers 3a, 4a, so that the total length of the double pipe 7 can be finished in the specified dimension even after the vulcanization.

Description

DETAILED DESCRIPTION OF THE INVENTION (Field of Industrial Application) The present invention relates to a method of vulcanizing a double pipe in which an elastic body such as rubber is interposed between an inner cylinder and an outer cylinder.

(Prior Art) Conventionally, when manufacturing a double pipe as shown in FIG. 3 in which an elastic body such as rubber is interposed between the inner cylinder and the outer cylinder, the square inner cylinder 7a
Elastic bodies 7b made of rubber or the like were inserted at equal intervals on the outer circumference of the inner tube 7a, and the inner cylinder 7a and the elastic body 7b were vulcanized and bonded using a real press, and then a lubricant was applied to the outer circumference of the elastic body 7b. The inner cylinder 7a was press-fitted from one end into the outer cylinder 7C, whose inner surface was coated with adhesive in advance, and the elastic body 7b and the outer cylinder 7c were bonded together by being vulcanized again by hot press. .

(Problems to be Solved by the Invention) In the double-pipe manufacturing method as described above, when the inner cylinder 7a is press-fitted into the outer cylinder 7c, the elastic body 7b is elastically deformed and residual strain is generated in the elastic body 7b. occurs.

However, in the conventional vulcanization method described above, VR is applied between the outer cylinder 7c and the elastic body 7b in a state where residual strain is generated within the elastic body 7b.
Due to the bonding lick and the relaxation of residual strain during vulcanization, the outside K
7 The inner cylinder 7a moves in the axial direction with respect to c, and the length cannot be finished to the specified dimensions.

For this reason, in the past, the inner and outer cylinders 7a and 7c were longer than the specified dimensions, and after the main vulcanization, the outer cylinder 7c and the inner cylinder 7a
The end face of the weaving machine was cut to give it a specified size, which required extra weaving work, resulting in poor work efficiency and increased material costs.

The present invention has been made to improve the above-mentioned drawbacks, and it is an object of the present invention to provide a method for vulcanizing double-walled pipes that eliminates the need for cutting after main vulcanization.

(Means for Solving Problems) In order to achieve the above object, the present invention includes inserting an elastic body into the outer periphery of the inner tube, vulcanizing it, and applying an adhesive to the inner surface of the outer tube. Next, after applying a lubricant to the elastic body inserted into the inner tube and press-fitting the outer tube into the inner tube, one end of the inner tube is pushed in a direction opposite to the press-fitting direction by an extrusion device. The inner and outer cylinder tubes are fixed by extruding the inner and outer tubes by pressing the other end into contact with a stopper jig, and in this state, the elastic body is vulcanized and the outer cylinder is bonded between the elastic body and the inner and outer tubes. .

(Function) As a result, even if residual strain occurs in the elastic body when the inner cylinder is press-fitted, the elastic body can be vulcanized while the movement of the inner cylinder is restricted, and this residual strain can be cured. Since the problem is resolved during curing, a double-walled pipe of a specified length can be obtained immediately after main vulcanization without having to cut the inner and outer cylinders as required in the past.

(Example) An example of the present invention will be described in detail with reference to the drawings shown in FIGS. 1 and 2.

Figure 1 shows a vulcanizing device such as a hot press. In this figure, 1 is a press plate, 2 is a hot plate, 3 is an upper mold, 4 is a lower mold, 5 is an extrusion device, and 6 is a stopper jig. , 7 indicates a double tube to be vulcanized, which is composed of an inner tube 7a, an elastic body 7b, and an outer tube 7c.

In manufacturing the double pipe 7, a plurality of annular elastic bodies 7b made of rubber are inserted into the square inner cylinder 7a at equal intervals, and then lubricant is applied to the outer peripheral surface of the elastic bodies 7b. The steps up to press fitting the inner tube 7a into the outer tube 7c whose inner surface has been coated with adhesive in advance are the same as those of the conventional method. Therefore, since the elastic body 7b is elastically deformed by press-fitting the inner cylinder 7a into the outer cylinder 7c at this time, residual strain is generated in the elastic body 7b when the inner cylinder 7a is inserted into the outer cylinder 7C. ing.

Next, the double tube 7 assembled as described above is housed between the upper mold 3 and lower mold 4 of the real press as shown in FIG. 2, and the upper mold 3 and lower mold 4 are closed. One end of the inner cylinder 7a is pushed out by the extrusion device 5 in a direction opposite to the direction in which the inner cylinder 7a is press-fitted, and the other end of the inner cylinder 7a is brought into contact with the striker/buckwheat jig 6 and fixed.

As a result, the elastic deformation that occurred in the elastic body 7b when the inner cylinder 7a was press-fitted is repaired, and the stopper jig 6 restricts the total length of the double pipe 7 to a specified range.

Next, in this state, the upper mold 3 and the lower mold 4 are
The elastic body 7b is heated to vulcanize the elastic body 7b.
b and the opening of the outer cylinder 7C, and is used to bond the elastic body 7b during vulcanization.
When the residual strain inside is relaxed by heat, even if an axial force acts on the inner cylinder 7a, the movement of the inner cylinder 7a is restricted by the stopper jig 6, and the outer cylinder 7c is moved by the upper mold 3. Since the position is regulated by the outer cylinder stoppers 3a and 4a when it is placed between the outer cylinder 7 and the lower mold 4, the entire length of the double pipe 7 can be finished to the specified dimensions even after the main vulcanization.

Note that an air cylinder, a hydraulic cylinder, a motor, or a mechanical extrusion means can be used as the extrusion device for extruding the inner cylinder 7a in the direction opposite to the press-fitting direction.

(Effects of the Invention) As described in detail above, the present invention, after press-fitting the inner cylinder into the outer cylinder through the elastic body, pushes the inner cylinder in the opposite direction to the press-fitting direction until the end of the inner cylinder comes into contact with the stopper means. push in the direction,
Since the outer cylinder and the elastic body are bonded together by vulcanization in this state, even if residual strain is generated in the elastic body when the inner cylinder is press-fitted, this residual strain will cause the axis of the inner cylinder to shift during vulcanization. This makes it possible to obtain double-pipe pipes with high overall length accuracy without any movement in the direction.

Since it is not necessary to cut to the full length or a specified length after vulcanization, the man-hours required for cutting are not required, and the material yield is improved, which is economical.

[Brief explanation of the drawing]

FIG. 1 is a schematic diagram of a vulcanization apparatus for carrying out the method of the present invention;
FIG. 2 is an enlarged view of the main part, and FIG. 3 is a sectional view of the double pipe to be vulcanized. 7a...Inner tube, 7b...Elastic body, 7C...Outer tube, 7...Double tube. Patent applicant: Atsukunisia Co., Ltd. Fig. 7a: 3 cylinders in I' 7b extensible punch body 7c 9) cylinder

Claims (1)

[Claims] After inserting an elastic body into the outer periphery of the inner tube, the elastic body is vulcanized, an adhesive is applied to the inner surface of the outer tube, and then a lubricant is applied to the elastic body inserted into the inner tube to close the outer tube. After the tube is press-fitted into the inner cylindrical tube, one end of the inner cylindrical tube is pushed out in a direction opposite to the press-fitting direction using a pushing device, and the other end is brought into contact with a stopper device to fix the inner and outer cylindrical tubes. , a method for vulcanizing a double tube, characterized in that the elastic body is vulcanized in this state and the outer tube is bonded between the elastic body and the outer tube.