JPH0142774B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a method for attaching a flange to a bellows used in an expansion pipe joint or a flexible joint.

[Prior Art] Expansion pipe joints and flexible joints absorb thermal expansion and bending loads when pipes and the like are subjected to them, and bellows having an accordion shape are often used.

Both ends of the bellows are usually provided with flanges,
Piping can be connected to this flange. Furthermore, when the flow velocity of the internal fluid increases, vibrations and turbulence occur in the bellows, so expansion pipe joints have also appeared in which an inner cylinder is provided inside the bellows to improve stability.

Conventionally, the bellows and the flange have been attached by welding, and other methods have also been adopted, such as crushing a portion of the peaks of the bellows and bringing the bellows into pressure contact with the flange.

These flange attachment means are shown in Figures 10 to 1.
It is shown in Figure 5. In Fig. 10, the flange 10 and bellows 11 are welded at their ends, and in Fig. 11, one peak 11a of the bellows 11 is crushed and the flange 11 is welded.
FIG. 12 shows an example in which the flange 10 is fixed by using the split ring 12 and the holding band 13 together.

FIG. 13 shows an example in which the inner cylinder 14 is integrally welded to the bellows 11 and the flange 10 at the end.
In Figure 4, the inner end of the ring plate 15 is connected to the bellows 11.
and is welded to the inner cylinder 14, and the flange 10 is clamped between the ring plate 15 and the peak of the bellows 11.
FIG. 15 shows an example in which the end of the inner cylinder 14 is pressed into contact with the type shown in FIG. 11 via a packing 16.

The other end of the inner tube 14 is free, that is, unfixed, so as not to hinder the expansion and contraction movement of the bellows 11.

[Problems to be Solved by the Invention] However, with the welding attachment method, there is a risk of thermal deformation and corrosion due to welding, and that pinholes, cracks, etc. may occur in the welded portion. Also,
When a fitting means is obtained in which a part of the bellows is crushed, there is a problem that sufficient bonding strength cannot be obtained between the bellows 11 and the flange 10. Furthermore, in the case of FIG. 15, there is a risk that the internal fluid may leak from the packing 16 portion, and in the case of vertical piping, the inner cylinder 14 may fall, resulting in the disadvantage that construction is labor-intensive.

[Object of the Invention] The present invention has been made in view of the above circumstances, and its purpose is to provide a non-welded type bellows flange attachment capable of firmly joining flanges to both ends of the bellows, regardless of the presence or absence of an inner cylinder. The purpose is to provide a method.

[Means for achieving the object] In order to achieve the above object, the bellows flange attachment method of the present invention includes a step of fitting a flange to a bellows having a straight pipe portion, and inserting a core metal into one end of the bellows. a step of fixing the flange with a first mold; a step of supporting an end of the bellows with a second mold disposed at a predetermined distance from the first mold; and two parts of the core metal. forming a sealed space in the straight pipe portion of the bellows using a sealing means provided in the bellows, inflating the straight pipe portion by introducing high-pressure fluid into the sealed space, and moving at least one of the molds to the other. The structure includes a step of bringing the expanded straight pipe portion close to each other and pressing the flange into contact with the flange.

Further, when an inner cylinder is provided inside the bellows, each of the above-mentioned steps is performed with the end of the inner cylinder overlapped with the inner surface of the straight tube part of the bellows.

[Function] With the above configuration, the straight pipe portion of the bellows is once expanded by the high-pressure fluid, and after the expanded portion is overlapped by the moving mold, the peak portion and the overlapped portion of the bellows move the flange on both sides in the axial direction. It will be firmly clamped. The outer diameter of the overlapping portion can be formed larger than that when the peaks are crushed, and therefore the clamping force of the flange is increased.

Further, when the straight pipe portion of the bellows and the inner cylinder are overlapped and brought into pressure contact with the flange, the clamping force is further increased.

[Example] FIGS. 1 and 2 show a forming apparatus 20 used in the flange attachment method of the present invention.

A core metal 21 is provided at the center of the molding device 20 so as to protrude rightward in the figure, and a bellows 22 is attached to the core metal 21.
The straight pipe portion 23 and inner cylinder 24 are fitted together. In this embodiment, an Ω-shaped peak portion 22a is used, but a U-shaped bellows can also be used.

A flange 25 is provided on the outer periphery of the bellows straight pipe portion 23.
are fitted, and one side thereof is in contact with the peak portion 22a. The flange 25 is fixed from the outside by a first mold 26, and the first mold 26 has a split mold shape and is installed on the frame 27 so as to be movable in the approach direction.

The core bar 21 has a tip 28, a rod 29, and a cylinder 3.
0 and a movable stopper 31. The distal end portion 28 is partially tapered, and has a shape into which the bellows 22 can be easily fitted. On the other hand, inner cylinder 2
4 is also formed with a tapered portion 24a, so when the bellows 22 is inserted into the core metal 21, the bellows 22
stops at the position shown in Figure 2.

The tip 28 is connected to the rod 29 by a bolt 32.
is connected to. A passage 33 for introducing high pressure fluid is formed in the central axis direction of the rod 29.
The outlet side (right side in the figure) is bent at 90 degrees and extends in the radial direction and is open. A movable stopper 31 is fixed to the rear end of the rod 29 by a nut 31a.

The cylinder 30 is slidably fitted into the rod 29, and its outer diameter is slightly smaller than the inner diameter of the inner cylinder 24. Further, in the radial direction of the cylinder 30, a plurality of holes 34 are provided which communicate with the passage 33 of the rod 29. Ring seals 35 and 36 are provided on the outer surface of the cylinder 30 at two locations.
The ring seals 35 and 36 protrude axially from the cylinder 30 in the normal state (FIG. 1).

A cylinder 37 is fitted behind the rod 29,
The front end of the cylinder 37 is in contact with the ring seal 36. A notch 38 is formed in the side wall of the cylinder 37, and the movable stopper 31 of the core bar 21 is inserted into the notch 3.
It protrudes outward through 8. A partition wall 39 is provided inside the cylinder 37, and a hole 40 in the center of the partition wall 39 is connected to an external hydraulic device 60.

The rear end of the cylinder 37 is closed with a cap 41, and a rod 43 passes through a hole 42 in the cap 41. A fixed piston 44 is attached to the tip of the rod 43.
The rear end of the rod 43 is fixed to the support plate 45 with a bolt 46. A hydraulic oil passage 47 is bored in the direction of the central axis of the rod 43, and this passage 4
7 is the piston connection part bent at 90 degrees and connected to the cylinder 37.
It leads to the inside of. A hole 48 communicating with the passage 47 of the rod 43 is also formed in the center of the frame 45, and the hole 48 is also connected to an external hydraulic device 60.

Therefore, when the hydraulic system 60 supplies hydraulic oil from the hole 40 of the partition wall 39, the cylinder 37 moves to the right as shown in FIG. 2, and when the hydraulic oil is supplied to the hole 48 side, the cylinder 37 moves to the left. When the cylinder 37 moves to the right, the ring seal 3 of the core bar 21
5 and 36 expand in the radial direction as shown in FIG.
9 is formed.

A second mold 50 is arranged around the core metal 21 at a predetermined distance from the first mold 26 . The second mold 50 is ring-shaped and maintains a constant distance from the core metal 21, into which the bellows 22 and the end of the inner cylinder 24 are inserted, as shown in FIG.

The second mold 50 is connected to a rod 53 of a hydraulic cylinder 52 by a bolt 51, and the hydraulic cylinder 52 is fixed to a fixed stopper 54. The hydraulic cylinder 52 has two hydraulic oil supply holes 55.
Since the holes 55a and 55b are provided, each hole 55a,
By alternately supplying hydraulic oil to 55b, the second mold 50 moves in the axial direction. Second mold 5
In order to balance the pressing force of 0, it is desirable to install a plurality of hydraulic cylinders 50.

The fixed stopper 54 not only supports the second mold and the hydraulic cylinder 52, but also, as can be seen in FIG. Also performs positioning. An end of the fixed stopper 54 is fixed to a surrounding frame 56.

A hydraulic device 60, a high pressure generator 70, and a control device 80 are installed outside the molding device 20.
The hydraulic system 60 supplies hydraulic oil to the central cylinder 37 and the hydraulic cylinder 52 as shown by arrows. Further, the high pressure generator 70 is connected to the passage 3 of the core metal 21.
3. Supply high pressure fluid to 3. The control device 80 performs sequence control of the hydraulic device 60 and the high pressure generator 70.

The operation order and operation procedure of the molding apparatus 20 configured as above are as follows.

First, the inner tube 24 is inserted inside the bellows 22, the flange 25 is fitted on the outside, and the bellows 22 is inserted into the core metal 21 of the molding device 20. At this point, a predetermined switch of the molding device 20 is turned on to fix the flange 25 in the first mold 26 as shown in FIG.

Next, hydraulic oil is supplied from the hydraulic system 60 to the hole 40 in the cylinder 37, and the cylinder 37
Move to the right in the figure. At this time, the movable stopper 31 of the core bar 21 moves slightly and then the fixed stopper 54 immediately moves.
However, the cylinder 37 further presses the ring seals 35 and 36. Therefore, the ring seals 35 and 36 expand radially outward and close the inner cylinder 2.
4, and a certain sealed space 49 is formed between both ring seals 35 and 36. Further, since the flange 25 and the first mold 26 are in contact with the outside of the ring seal 35, and the second mold 50 is in contact with the outside of the ring seal 36, the bellows straight pipe portion 23
Then, the inner cylinder 24 will be firmly fixed.

Subsequently, the passage 3 of the core metal 21 from the high pressure generator 70
When high-pressure fluid is pressurized into the tube 3, the fluid flows into the sealed space 49 through the passage 33 and the hole 34, as shown in FIG. . When the straight pipe section 23 expands by a predetermined amount, the high pressure fluid is removed or the pressure is reduced.

Next, hydraulic oil is supplied from the hydraulic system 60 (FIG. 1) to the supply hole 55a of the hydraulic cylinder 52, and the fourth
As shown in the figure, the second mold 50 is connected to the first mold 26.
Move in the direction of the arrow until it touches the. For this reason,
The expanded straight pipe portion 23 and inner cylinder 24 are pressed against the outer surface of the flange 25 in an overlapping state, and the flange 2
5 is the overlapping part 23a and the peak part 22 of the bellows
It is firmly held by a. The second mold 50 includes
Notch 5 just enough to receive the overlapped portion 23a
It is desirable to form 0a in advance.

When the molding process is finished, the hydraulic device 60 supplies hydraulic oil to the supply hole 55b of the hydraulic cylinder 52 (FIG. 1), so the second mold 50 retreats as shown in FIG. 5.

Subsequently, the hole 48 of the support plate 45 is connected to the hydraulic device 60.
When hydraulic oil is supplied to the piston 44, the hydraulic oil flows to the left side of the fixed piston 44 through the passage 47 (Fig. 1).
The cylinder 37 also moves back as shown in FIG. Further, the first mold 26 is also moved to release the flange 25 from being fixed. Therefore, the ring seals 35 and 36 of the core bar 21 return to their original shapes and separate from the inner cylinder 14, and the bellows 22 after the flange is attached to the core bar 2.
It can be extracted from 1.

Next, the bellows 22 that has been pulled out is attached in reverse, and the flange 25 is attached to the other end in the same process. However, as can be seen from FIG. 7, only the bellows straight pipe portion 23 is molded at the other end, and the inner cylinder 24 is left free. With this configuration, the bellows 22 is not hindered from expanding and contracting even if the inner tube 24 is present.

After completing the flange attachment of the bellows 22, the remaining straight pipe portion 23 is cut off as shown in FIG.
When using the bellows 22, it is connected to piping or the like so that fluid flows in the direction of the arrow in the figure.

FIG. 9 shows an embodiment in which a flange 25 is attached to a bellows 22 without an inner cylinder 24. In this case, only the straight pipe portions 23 at both ends of the bellows are processed in the same manner as described above to attach the flanges 25, and the remaining straight pipe portions 23 are cut off. This bellows 22 is
Can be connected to piping, etc. regardless of the direction of fluid.

The overlapping portion 23a of the bellows 22 formed as described above can be formed larger in the radial direction than when the peak portion 22a is crushed. In other words, since the area of the overlapping portion 23a that comes into pressure contact with the flange 25 becomes larger, the flange 25 is firmly joined to the bellows 22. Further, since the inner cylinder 24 is also molded together with the bellows straight pipe portion 23, packing is not necessary and there is no fear that the inner cylinder 24 will come off from the bellows 22.

In the above embodiment, the second metal mold 50 is moved to perform the molding process, but either of the metal molds may be moved. Further, although the ring seals 35 and 36 are pressed by the cylinder 37 to form the sealed space 49, other sealing means and pressing means can also be employed.

[Effects of the Invention] As explained above, the flange attachment method of the present invention includes the steps of fitting a flange to a bellows having a straight pipe portion, inserting a cored metal into one end of the bellows, and inserting a metal core into one end of the bellows. a step of fixing the flange; a step of supporting the end of the bellows with a second mold placed at a predetermined distance from the first mold; and a sealing means provided at two locations on the core metal. forming a sealed space in the straight pipe portion of the bellows; introducing high-pressure fluid into the sealed space to expand the straight pipe portion; and bringing at least one of the molds close to the other mold to expand the straight pipe portion. Since the structure includes the step of press-welding the bellows and the flange to the flange, there is an effect that the bellows and the flange can be firmly joined without using welding.

In addition, in the case of a bellows with an inner cylinder, the two ends are overlapped and pressed against the outer surface of the flange, so the flange, bellows, and inner cylinder can be firmly joined without the need for welding, etc. , there is no need to worry about the inner cylinder falling when installing the bellows.

[Brief explanation of drawings]

Fig. 1 is a longitudinal sectional view of a forming device used in the flange attachment method of the present invention, Fig. 2 is a longitudinal sectional view showing a state in which a bellows is attached, and Figs. 3 to 6 show the operating state of the forming device. Fig. 7 is a longitudinal sectional view showing the bellows with an inner cylinder after molding;
The figure is a longitudinal sectional view of the completed bellows with inner cylinder, No. 9.
The figure is a vertical sectional view of a bellows without an inner cylinder, Figure 10~
FIG. 15 is an enlarged sectional view showing a conventional bellows. 20... Molding device, 21... Core metal, 22... Bellows, 23... Straight pipe portion, 23a... Overlapping portion, 2
4... Inner cylinder, 25... Flange, 26... First mold,
33... High pressure fluid passage, 35, 36... Ring seal, 37... Cylinder, 49... Sealed space, 50... Second mold, 52... Hydraulic cylinder, 60... Hydraulic device, 70... High pressure generator, 80... Control Device.

Claims (1)

[Claims] 1. A step of fitting a flange to a bellows having a straight pipe portion, a step of inserting a core metal into one end of the bellows and fixing the flange with a first mold,
A step of supporting the end of the bellows with a second mold placed at a predetermined distance from the mold, and forming a sealed space in the straight pipe portion of the bellows using sealing means provided at two places on the core metal. and a step of introducing high-pressure fluid into the sealed space to expand the straight pipe portion.
A method for attaching a bellows to a flange, the method comprising the step of bringing at least one of the molds close to the other to press the expanded straight pipe portion against the flange. 2. A step of fitting an inner tube and a flange to a bellows having a straight pipe portion, a step of inserting a core metal into one end of the bellows and the inner tube and fixing the flange with a first mold, and a step of fixing the flange with a first mold. a step of supporting the end portion of the bellows with a second mold arranged at a predetermined interval; and a step of forming a sealed space inside the inner cylinder with sealing means provided at two places on the core metal. Introducing high-pressure fluid into the sealed space to expand the straight pipe part and the inner cylinder together; and bringing at least one of the molds close to the other to press the expanded straight pipe part and the inner cylinder against the flange. Bellows flange installation method, including process. 3. A patent claim in which the sealing means is a ring seal fitted into the core metal, and the ring seal is compressed in the axial direction, expands outward, and comes into pressure contact with the inner surface of the inner cylinder to form the sealed space. The method for attaching the bellows to the flange according to item 2. 4. The bellows flange attachment method according to claim 2, wherein the second mold is moved in the axial direction by hydraulic means and crushed with the straight pipe portion and the inner cylinder overlapped. . 5. The bellows flange attachment method according to claim 2, wherein the high-pressure fluid is introduced into the sealed space through a passage formed inside a core metal.