JPS59296B2 - Manufacturing method of spherical flexible pipe joint - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method of manufacturing a flexible pipe joint by expanding a metal pipe into a spherical shape.

Traditionally, this type of flexible pipe fitting consists of many parts,
Complex and highly accurate dimensions were required. For example, in the case of the spherical bending pipe joint shown in FIG. 1, a casing 1 includes a connecting portion 1a, an endothelial tube 2 includes a spherical portion 2a, a flange 3 attached to the upper end of the casing 1, and a flange 3 attached to the upper end of the connecting portion 1a. It consists of gaskets 4 and 5, bolts 6 that fix the flange 3, etc., but manufacturing these parts requires many steps, especially the gasket attachment part of the casing 1 and the spherical part of the endothelial tube 2. The finished dimensions of 2a were required to be highly accurate. The present invention provides a flexible pipe joint in which an outer shell pipe and an inner pipe are connected in a flexible state by sliding contact of a spherical part, by expanding and molding a commercially available metal pipe within a spherical mold cavity using hydraulic pressure. The present invention provides a manufacturing method that enables mass production of highly accurate, compact, inexpensive, and high quality spherical flexible pipe joints. Hereinafter, the present invention will be explained based on the drawings.

FIGS. 2 to 6 show an example of the manufacturing process from a metal tube to a spherical flexible pipe joint. First, as shown in FIGS. While applying high hydraulic pressure to the inside of the tube, the material tube 10' is pressed in the axial direction to form a spherical shell portion 10a.

The method of bulging the spherical shell portion 10a will be explained with reference to FIG. In this figure, the left half of the center line is shown before the expansion molding, and the right half is shown after the expansion molding is completed. At the same time, the end sealing plug 15 with the hydraulic pressure introduction passage 14 opened at the central protrusion 15a is fixed, and the lower mold 16 is fixed above it, and the convex part 15a of the end sealing plug 15 and the lower molding are fixed. A gap is formed with the mold 16 into which the lower end of the material tube 10' is inserted. In addition, the lower mold 16 and the upper mold IT
are formed with mold cavities 16a and 1Ta for forming a spherical shell in the material tube, respectively, and the upper mold IT is as follows:
The pressurizing breath head 18 is capable of vertical movement on the lower mold 16 in the guide tube 13, and the insertion hole 19 of the material tube 10' in the upper mold IT is provided with a hole provided on the upper mold 17. An upper end sealing plug 21, which also serves as a knockout and is moved vertically by a knockout cylinder 20, is fitted and inserted so as to be vertically movable. In addition, 22 in the figure is an air vent hole, 2
3 and 24 indicate O-rings for sealing. To carry out expansion molding using the processing machine configured as described above, first, the upper mold 17 is raised to the upper limit by the pressure press head 18 and separated from the guide tube 13, and the lower end of the material tube 10' is moved to the seventh position.
As shown in the left half of the figure, it is inserted into the gap between the center protrusion 15a of the end sealing plug 15 and the lower mold 16, and the pressurizing breath head 1
8 lowers the tip of the upper end sealing plug 21 to the material tube 10'.
Lower it until it hits the top surface of the

In this case, a gap 25 is maintained between the upper mold 17 and the lower mold 16. Next, high liquid pressure is introduced into the material tube 10' from the liquid pressure introduction path 14, but this high liquid pressure pushes up the upper end sealing plug 21, so it is transferred to the pressure press head. It is necessary to reduce the pressure at 18. When high liquid pressure is introduced into the material pipe 10', the pressure press head 1
8, the upper mold 17 is further applied with a size pressurizing force.
is lowered until the gap 25 disappears, and the material tube 10' is compressed in the axial direction. The material tube 10' is then compressed into the upper mold 17 and the lower mold 1 by the high hydraulic pressure and axial compressive force.
It is bulged and deformed so as to come into close contact with the inner surfaces of spherical mold cavities 16a and 17a formed by 6 and 6. The right half of FIG. 7 shows this state. After that, the high liquid pressure from the liquid pressure introduction path 14 is released, and the upper mold 17 is moved to the pressure press head 18.
By moving it upward, the bulge-molded outer shell pipe material pipe 1
0' also moves upward while being fitted into the upper mold 17, and therefore, by introducing hydraulic pressure into the lowering port 20a of the knockout cylinder 20, the upper end sealing plug 21, which also serves as a knockout, is lowered. , from the upper mold 17 to the outer shell pipe material pipe 10'
755 is separated and the expansion molding is completed. Note that the air vent hole 22 is for releasing air or liquid existing in the gap 25 and mold cavity to the outside during the expansion process. The end portion and part of the spherical portion of the outer shell pipe material tube 102 thus obtained are removed by turning, thereby obtaining the outer shell pipe 10 shown in FIG. 4.

The inner wall of the spherical shell portion 10a of the outer shell tube 10 is required to have sphericity and circularity because it comes into sliding contact with the endothelial tube 11 described later. However, in this invention, the sphericity is not used. Since it depends on the shape of the mold cavity of the mold to be molded, there is no need for cutting and finishing of each molded product as in the conventional method. Regarding concavity, it is sufficient to make the portion corresponding to the inner wall surface of the material tube circular, and since the shape is a simple cylindrical inner wall surface, the finishing method is also easy. Next, a method for attaching the outer surface of the spherical portion 11a of the endothelial tube 11 to the inner wall of the spherical shell portion 10a of the outer shell tube 10 will be described.

FIG. 5 shows the state before the end of the endothelial tube material tube 11' is inserted into the spherical shell portion 10a of the outer shell tube 10 and is mounted, and FIG. 6 shows the state before the end of the endothelial tube material tube 11' The end of the tube is bulged into a spherical shape to form an endothelial tube 11, which is then used as an outer shell tube 10.
It shows a state where it is attached to the inner wall of the spherical shell portion 10a.

The configuration of the processing machine used for attaching the endothelial tube 11 is approximately the same as that for the bulge molding of the outer shell tube, as shown in FIG. To explain this point, the lower mold 26 includes a mold cavity 27 and a fitting hole 28 having the same shape as the upper mold 17 in FIG. 7, and is fixed in a guide tube 29.

On the other hand, an upper mold 30 for expanding and molding the endothelial tube 11
The mold cavity 31 provided at the lower end is composed of a large diameter portion 31a that fits into the spherical shell portion 10a of the outer shell tube 10, and a small diameter portion 31b that fits into the spherical portion 11a of the endothelial tube 11. , an air vent hole 32 is provided for releasing air or liquid present in the mold cavity 31 and the spherical shell portion 10a of the outer shell tube 10 to the outside during the swelling molding process of the endothelial tube 11.

In order to bulge and mold the endothelial tube 11 into the outer shell tube 10 using the above-mentioned processing machine, as shown in the left half of FIG. The outer shell tube 10 formed as described above is removed from the cylinder 29 and inserted into the lower mold 26 as shown in the figure, and the outer circumference of the distal end of the endothelial tube material tube 11' forms a spherical shape of the outer shell tube 10. The endothelial tube material tube 11' is inserted so as to come into contact with the rear end 33 of the shell portion 10a.

Next, the pressure press head 18 is lowered until the tip of the upper end sealing plug 21 abuts against the upper end surface of the endothelial tube material tube 11'. Excessive impact force at the time of impact causes the contact position of the spherical shell portion 10a with the rear end 33 to move downward, thereby inhibiting the spherical expansion of the endothelial tube, which will be described later. Therefore, the magnitude of the impact force is determined between the tip of the endothelial tube material tube 11' and the outer shell tube 1.
The surface pressure generated at the point of contact with the spherical shell portion 10a of 0 should be within the elastic limit. After the upper mold 30 is lowered to a position where the gap 34 is maintained with respect to the lower mold 26, the outer shell pipe is removed from the hydraulic pressure introduction passage 14 by the same method as the expansion molding of the outer shell pipe 10. 10 and the material pipe 11' for the endothelial pipe, and at the same time, a larger pressure is applied by the pressure press head 18 to form the upper mold 30.
The material tube 11' for the endothelial tube is compressed in the axial direction by lowering the material tube 11' until the gap 34 disappears, and as shown in the right half of FIG. The lower end of the tube 11' is bulged into a spherical shape along the small diameter portion 31b in the mold cavity 31 of the upper mold 30 and the inner wall of the spherical shell portion 10a of the outer shell tube 10.

As a result, the spherical portion 11a of the endothelial tube 11 is slidably brought into close contact with the inner wall of the spherical shell portion 10a of the outer shell tube 10. The operation for removing the spherical flexible pipe joint in which the endothelial pipe 11 is connected to the outer shell pipe 10 from each type is the same as that for removing the outer shell pipe material pipe 10'0), and its description will be omitted.

The thus obtained spherical flexible pipe joint has flexibility due to the sliding contact between the inner wall of the spherical shell portion 10a of the outer shell tube 10 and the outer surface of the spherical portion 11a of the endothelial tube 11.

In addition, the shape of the processing machine for swelling molding was vertical, but
It can also be made horizontal depending on the size and shape of the joint. The present invention can also be applied to the manufacture of a gasket-enclosed spherical flexible pipe joint in which a gasket is attached to improve the oil-tightness at the sliding contact portion between the outer shell pipe and the inner pipe.

In this case, first, as shown in FIG. 9, the outer shell tube 10 provided with the gasket mounting groove 35 is molded, but the processing machine shown in FIG. 11 is used for the expansion molding. Ru. The configuration of this processing machine and its molding method are substantially the same as those shown in FIG. is provided in a circumferential shape, and a gasket mounting groove 35 is formed in the outer shell tube 10 by this recess. In this case, in order to properly enclose the gasket and further improve oil-tightness, it is preferable to internally turn the inner corners of the gasket mounting groove 35 to form acute angles.

Next, the spherical portion 11a of the endothelial tube 11 is attached to the inside of the spherical shell portion 10a of the outer shell tube 10. This method is performed by attaching the endothelial tube 11a to the inner wall of the spherical shell portion 10a of the outer shell tube 10 described based on FIG. The difference is that before the endothelial tube 11 is attached, a gasket 40 is fitted into the gasket attachment groove 35 of the outer shell tube 10 as shown in FIG. The endothelial tube 1 is formed using upper and lower molds with mold cavities that match the shape of the shell part 10a.
This is the point where 1 is bulged. The gasketed spherical flexible pipe joint thus manufactured is shown in FIG. By a similar method, as shown in FIG.
It is also possible to form flexible pipe fittings equipped with

Next, an example of molding a spherical flexible pipe joint shown in FIG. 6, which was performed by the method of the present invention, will be described.

The materials of the raw tubes were low carbon steel tubes and 18-8 stainless steel tubes, the outer diameter of which was 40 mm, the wall thickness of the former was 21E11, and the latter was 1.5 mm, and the total length was 140 mm. The forming conditions for the material pipe for the outer shell pipe are, in the case of low carbon steel pipes, the gap between the upper and lower molding molds is 13m11, and the high liquid pressure acting inside the material pipe is set to an initial pressure of 350k? Effective ~, final pressure is 1000
kg/CfL2, and the pressing force of the pressure press head was about 30 tons. For stainless steel pipes, the gap is 12.5m11, and the initial pressure is 300k for high hydraulic pressure.
9/Fm2, the final pressure was set to 1200 k9/d, and the pressing force of the press head was about 35 tons. The ends and a portion of the spherical shell of the material tube for the outer shell pipe obtained in this manner were removed by turning, to obtain an outer shell pipe with a total length of 11,011 mm. Next, the expansion molding conditions for attaching an endothelial tube to the inner wall of the spherical shell of the outer shell tube to form a spherical flexible pipe joint are approximately the same as those for the raw material tube for the outer shell tube for both the low carbon steel tube and the stainless steel tube. Only is slightly smaller, the former is 11111, the latter is 10
．． It is 5n.

The total length of this material tube for endothelial tube was 120 mm. Furthermore, the degree of flexibility of the pipe joint after completion of molding seemed to qualitatively depend on the magnitude of the final pressure. As described in detail above, according to the present invention, a metal tube is used as a material and bulge molding is performed by cold plastic deformation using a mold, so that a high quality, small and lightweight spherical flexible tube can be produced. Joints can be mass-produced economically.

[Brief explanation of drawings]

Figure 1 is a cross-sectional view of a conventional spherical bending pipe joint, Figures 2 to 6
The figure is a cross-sectional view showing the manufacturing process of a spherical flexible pipe joint using a metal tube, and Fig. 7 is a cross-sectional view showing the manufacturing process of a spherical flexible pipe joint using a metal tube. Fig. 8 is a sectional view showing the structure and forming process of a processing machine for forming the outer shell tube, and Fig. 8 is a cross-sectional view showing the structure and forming process of the processing machine for attaching the inner shell tube. A cross-sectional view of the outer shell pipe for the spherical flexible pipe joint and the finished product, Fig. 11 is a cross-sectional view showing the processing machine and the first molding process, and Fig. 12 shows different flexible pipe joints that can be manufactured by the method of the present invention. FIG. 10, 41...Outer shell pipe, 102...Material tube for outer shell pipe, 10a, 42...Spherical shell part, 1
1, 43... Endothelial tube, 11'... Material tube for endothelial tube, 11a... Spherical part, 16, 26,
36...Lower mold, 16a, 17a, 27,
31, 38, 39... type fossa, 17, 30, 37
・・・・・・Upper mold.

Claims (1)

[Claims] 1. Arranging an upper mold and a lower mold for forming the outer shell pipe at both ends of the raw material pipe for the outer shell pipe, and pressing the upper mold toward the lower mold while applying high liquid pressure to the inside of the pipe. Then, a spherical shell is bulged in a part of the tube in line with the spherical mold cavity formed by the two molds, and the outer shell tube thus formed is molded into a lower part for attaching the endothelial tube. One end of the material tube for the endothelial tube is inserted into the spherical shell while being held in the mold, and the other end of the material tube is inserted into the upper mold to apply high hydraulic pressure to the inside of the material tube for the endothelial tube. By pressing the upper mold toward the lower mold while moving, the material tube for the endothelial tube is bulged along the inner wall of the spherical shell of the outer shell tube, and the spherical portion of the endothelial tube is formed into the outer shell tube. 1. A method for manufacturing a spherical flexible pipe joint, characterized in that the spherical flexible pipe joint is slidably installed in a spherical shell.