JPS5865529A - Pipe expanding method - Google Patents

Abstract

PURPOSE:To prevent damage of a pipe with respect to a pressure pipe, etc., and to obtain a smooth diameter expanded surface, by expanding and forming the main part of a pipe, and also the auxiliary pipe end part, by a rubber pipe- expanding method and a cellect chuck pipe-expanding method, respectively. CONSTITUTION:The whole of seal rubber products 28, 30 and flare rubber 29 which have been installed to a fitting shaft 24 is placed in one end part of a pressure pipe 38, and by driving of a pipe-expanding ram, the shaft 24 is moved in the lead-in direction (in the right direction in figure). As a result, between a seal ring 33 and a metallic die opposing part 17A of a moving base 17, the rubber products 28, 29 and 30 are compressed, and by bulging of the rubber product 29, the end of a pressure pipe 32 is expanded. In this case, a rubber product 28 placed part is left as a pipe-unexpanded part. Subsequently, the rubber part is detached, a tapered guide part 36 on which a collect chuck mechanism 23 has been placed is provided, the shaft 24 is moved in the lead-in direction, a split ring 37 is expanded in its diameter by the guide part 36, and a diameter-unexpanded part 32B of the pipe 32 is expanded in diameter.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention provides a method for expanding a pressure pipe with a large amount of expansion,
In particular, the present invention relates to a tube expansion method that prevents tube damage and provides a smooth diameter expansion surface.

Conventionally, for example, when expanding a pressure tube for a nuclear reactor to form an enlarged diameter part for airtight fitting connection at the end of the pressure tube, as shown in Fig. 1, a die 2 is pushed into the pressure tube 1 to expand the tube. The common method was to However, according to this method,
Scratches occur on the inner surface of the pressure tube 1 due to metal contact with the die 2, and processing is required to remove these scratches.
It took a lot of processing time. In particular, the enlarged diameter part of the pressure pipe for connection requires high airtightness, so if it is extremely damaged, it must be removed. It is desirable to reduce or avoid it as much as possible. However, the degree of diameter expansion of this kind is large, for example, about 10 times, and when conventional dies are used, the occurrence of scratches is almost unavoidable.

The present invention has been developed in view of these circumstances, and is effective in reducing scratches on the inner surface of the tube, eliminating the need for cumbersome finishing work as a post-processing process, and making efficient use of expensive pressure tubes and the like. The purpose is to provide a method for expanding tubes.

In order to achieve such an object, the present invention expands the main part of the tube by a rubber tube expansion method and the auxiliary tube end by a collect chuck tube expansion method, in particular, forming the main tube expansion part with almost no damage. It was designed to do so. In other words, the rubber tube expansion method applies internal pressure to the tube using rubber as a medium with no metal contact, to prevent the occurrence of scratches on the inner surface of the tube. 1, and as it is, it will be necessary to cut and remove the unexpanded portions of the expensive pressure pipes. Therefore, after rubber tube expansion, the unexpanded portions are expanded using a mechanical collect chuck method.

Hereinafter, one embodiment of the present invention will be described in detail with reference to FIGS. 2 to 7.

In this example, a pressure pipe with an inner diameter of about 120 rIR1 and a wall thickness of about 4.5 mm is connected to a pressure pipe with an inner diameter of 130 mm within a range of about 100 m from the pipe end.
(Approximately 10% in terms of deformation amount) This is the case when the pipe is expanded.

FIG. 2 shows the overall configuration of a pressure tube diameter expansion device for carrying out the method of the present invention. A mold support stand 11 is erected on a horizontal base 10, and this mold support stand 11
Rails 12 are laid in the far and near directions. A cylindrical mold 13 divided into two in the radial direction is supported on the mold support stand 11 with its axis horizontal. This mold 13 is tapered on the outer periphery of both ends so that the diameter becomes smaller on the end side. Tightening flanges 14 and 15 fitted to a portion of each taper are tightened with bolts 16 whose axes are parallel to the mold 13, and the mold 13 is fixed by this tightening force. .

Further, a movable table 17 is placed on the rail 12 so as to be slidable along the rail 12 via a movable member 18 . The moving table 17 is connected via a rod 20 to a drive ram 19 fixed to the end of the base 10, and can be moved toward and away from the mold 13 within a certain range by detecting the position with a limit switch 21. ing.

In addition, the moving base 1 set by the limit switch 21
The operating range of No. 7 is set to a range in which the shaft is inserted into and discharged from the mold 13 when installing the rubber tube expansion mechanism, which will be described later.

A rubber tube expansion mechanism 22 and a collect chuck mechanism 23 are attached to the moving table 17 via a shaft 24. The shaft 24 is attached to the actuating portion 26 of a tube expanding ram 25 provided on the side opposite to the mold of the movable table 17 so as to be retractable toward the mold 13. In this installation, the shaft 24 is slidably supported on the movable table 17. The movable table 17 can be detachably fixed to the movable table side flange 15 of the mold 13 using a fixture such as a port 27.

Next, the rubber tube expansion mechanism 22 will be explained. FIG. 2 shows the rubber tube expansion mechanism 22 mounted on the shaft 24, and FIG. 3 shows an enlarged cross-sectional shape of the rubber tube expansion mechanism 22. Note that FIG. 2 shows the state before tube expansion molding, and FIG. 3 shows the state after tube expansion molding. For installation, a ring-shaped seal rubber 28 made of urethane rubber or the like, a cylindrical flare rubber 29 made of silicone rubber, etc., and a second seal rubber 30 similar to the above are fitted and attached to the distal end side of the shaft 24 in order from the base end side. are doing. Each of the knob rubbers 28 and 30 is made of a pair of rubber materials mated in the axial direction of the shaft 24, and is joined via a tapered surface 31, respectively. That is, each seal rubber 28.30 is a respective rubber material 28A.

28B, 30A, and 30B are attached to the outer end side 18A when the shaft 24 is compressed in the axial direction.

30A expands in the diametrical direction and comes into close contact with the inner circumferential surface of the pressure pipe 32 to provide a high degree of sealing effect.

In addition, flare rubber 29. Seal rubber 28, . The outer diameter of the pressure pipe 30 is normally set to be slightly smaller than the inner diameter of the pressure pipe 32. Then, the seal rubber 30 on the tip side of the shaft 24 is installed.
This attachment is secured by a nut 35 screwed into the threaded portion 34 of the shaft 24 via a seal ring 33.

In addition, about 10 pressure pipes 32 are installed on the molding surface 13A of the mold 13.
A diameter-expanding shape is applied to increase the diameter.

However, when expanding the pressure pipe 32 using the lever expansion mechanism 22, first, the expansion ram 25 is used to make the shaft 24 protrude as much as possible from the movable table 17 toward the mold 13. The moving table 17 is attached by the operation of the drive ram 19 to the pressure pipe 3 whose shaft 24 is held in the mold 13.
2. Move it as much as possible in the direction of insertion. Then, the movable table 17 is fixed to the 7-lunge 15 with bolts 27.

Then, the seal rubber 28 attached to the shaft 24 is installed.
．． 30 and the flare rubber 29 are now entirely disposed within one end of the pressure tube 38.

Therefore, when the tube expansion ram 25 is driven to move the shaft 24 in the retracting direction (to the right in the figure), the installation is performed using the seal ring 33 fixed to the shaft 24 and the flare rubber 29 and seal rubber 28. 30
is compressed between the mold opposing portion 17A of the moving member 617, and the flare rubber 29 is expanded in the outer circumferential direction due to the compressive force. As a result, the end of the pressure tube 32 is expanded along the molding surface 13A of the mold 13. In this case, the pressure pipe 32 receives a force acting in the direction of pipe expansion by the flare rubber 29, and since the flare rubber 29 has flexibility, the inner peripheral surface portion 32 whose diameter has been enlarged
A has no scratches at all. In addition,
When this rubber tube expansion action is performed, each seal rubber 28 expands in diameter in the outer circumferential direction due to compression force, as described above, so that both ends of the expanded portion of the pressure tube 32 are reliably sealed. be.

In this manner, at the distal end portion of the pressure tube 32 expanded by the tube expansion mechanism 22, the portion where the seal rubber 28 is disposed remains as an unexpanded portion with a small diameter. Therefore, after the tube is expanded, the tube expansion ram 25 is driven to attach it to the shaft 24.
The flare rubber 29 is moved to protrude toward the tip side again, and the flared rubber 29 is released from its swollen state and returned to its original small diameter state as shown in FIG. 2, for example. After removing the bolt 27 from the moving table 17, the driving ram 19 is driven to move the moving table 17 and the entire body away from the mold 13 (to the right in the figure).
The rubber tube expanding mechanism 22 is thereby pulled out from the mold 13 and the pressure tube 32.

Next, a second pipe expanding action on the unexpanded portion of the pressure pipe 32 by the collect chuck mechanism 23 will be explained, but the collect chuck mechanism 23 is also attached to the shaft 24 as described above. For this reason, the rubber tube expansion mechanism 22
After the molding is completed, remove the tightening nut 35 and seal ring 33 from the shaft 24, and remove the flare rubber 29 and seal rubber 28, 30.

For attachment, a tapered guide portion 36 for a collect chuck is formed at the tip of the shaft 24, with the tip gradually becoming larger. The collect chuck mechanism 2 is attached to this guide portion 36.
I am trying to install 3. That is, FIG. 4 shows the tube expansion action by the collect chuck mechanism 23, and FIG. 5 is an enlarged view of the main part thereof. Moreover, FIG. 6 schematically shows the shape of the collect chuck in the axial direction. As a collect chuck, a plurality of divided rings 37 are attached to the tip of a cylindrical support 40 arranged around one circumference of the shaft 24. This division ring 37 can be divided into any number of divisions, such as 6 divisions as shown in FIG. 6, or 12 divisions as shown in FIG. 6. An engaging surface 37A having the same taper as the guide portion 36 is formed on the inner circumferential surface of the split ring 37, and the outer circumferential surface has a constant outer diameter. A gap is provided between each split ring 37 for expanding the diameter of the unexpanded portion 32B to the same shape as the first expansion action of the pressure tube 32 by the rubber tube expansion mechanism 22.

When performing the second tube expansion action using such a collect chuck mechanism 23, the split ring 37 is fitted and attached to the shaft 24 via the sabot 40, and the above-mentioned expansion action is performed by driving the drive ram 19 and tube expansion ram 25. In the same manner as the first tube expansion operation, the shaft 24 is inserted into the pressure tube 32 and the split ring 37 is placed in the unexpanded diameter portion 32B of the pressure tube 32.

Thereafter, by driving the tube expansion ram 25, the attachment shaft 24 is moved in the direction of drawing it toward the tube expansion ram 25 (to the right in the figure). Then, the split ring 37 becomes the support 40
During installation, only the shaft 24 moves in the same direction, and the engaging surface 37A of the split ring 37 is gradually pushed wider due to the taper of the guide portion 36 at the tip of the shaft. Then, the outer peripheral surface 3 of the split ring 37
7B, the pressure pipe 32 is expanded until the tapered portion 32B of the pressure pipe 32 coincides with the molding surface 13A of the mold 13. In this case, since the split ring 37 is made of metal, it may cause scratches on the inner circumferential surface of the pressure tube 32 as in the past, but this molded part is the most distal part of the pressure tube 32. This does not pose any particular problem when joining pressure tubes after tube expansion. Incidentally, even if it is necessary to remove scratches, it is sufficient to process only the end of the tube, so the correction process can be done very easily. After the second tube expansion action by the collect chuck mechanism 23 is completed, the port 27 is removed in the same manner as described above, and the drive ram 19
For installation, the shaft 24 and the split ring 37 can be removed from the mold 13 and the pressure pipe 32 together with the moving table 17 by driving.

The hydraulic system for driving each of the rams 19 and 15 described above will be explained with reference to FIG. A pair of pumps 51, 52 which can be switched and used are connected to the oil tank 50, and a solenoid valve 55 for manual operation is connected to each of these pumps 51, 52 via check valves 53, 54. This solenoid valve 5
Oil is supplied to the pressure chamber of the drive ram 19 from one outlet of the drive ram 19 through an inlet pipe 56. One oil chamber 57 of the drive ram 19 is connected to an automatic operation solenoid valve 60 via a check valve 58 and a throttle valve 59, and the introduction pipe 56 is connected to this solenoid valve 60. Also, the other oil chamber 6 of the ram 19
1 is connected to the electromagnetic valve 60. This automatic operation solenoid valve 60 is configured to drive the solenoid valve 60 to a neutral position when pressure above a predetermined level is detected by pressure detection switches 62, 63 connected to each oil chamber 57, 61, respectively. Note that 64 and 65 are pressure indicators attached to the pressure detection switches 62 and 63. Further, the expansion ram 25 is also provided with a circuit substantially similar to that of the drive ram 19 described above. Specifically, 70 is an automatic operation solenoid valve, 71 is a check valve, 72 is a throttle valve, 73 is one oil chamber, 74 is the other oil chamber, 75 is a check valve, 76 and 77 are a pressure detection switch and a pressure detection switch, respectively. It is a pressure indicator. Further, 78 is a pressure switch with contacts for operating a separately provided safety valve. In addition, this is the pressure detection switch and pressure indicator installed on the 79.80 pump side.

When performing pipe expansion using such a hydraulic system,
As mentioned above, the drive ram 19 and the tube expansion ram 25 are switched in relation to each other. In this case, for example, as shown in FIG. Solenoid valve 5 for
5 to drive one pump 51 as shown in the figure to supply oil from the oil tank 50 to the drive ram 19.

In this case, the solenoid valve 60 is moved from the neutral position to the parallel side 60A in the figure.
, so that oil is supplied to one oil chamber 57 of the drive ram 19 through the check valve 58.

Then, the piston portion 19' of this drive ram 19 moves in the projecting direction. That is, in FIG.
moves in the protrusion direction, thereby causing the moving table 17 to move toward the mold 1.
3. In this case, the predetermined approach position is detected by the pressure detection switch 63, and the solenoid valve 60 returns to the neutral position again. Therefore, the first tube expansion operation by the tube expansion mechanism 22 may be performed as described above.

In this case, the hydraulic pressure is lowered by switching to the low-pressure pump 52, and the solenoid valve 55 is manually switched to the crossing side 55A. Then, the oil pressure is the drive ram 1
9 side to the tube expansion ram 25 side. Therefore, move the solenoid valve 70 on the expanded pipe Ramse 5 side from the neutral position shown in the figure to the crossing side 70.
A, and apply hydraulic pressure to the second oil chamber 74 of the tube expansion ram 25. As a result, the piston portion 25' of the tube expansion ram 25 is moved to the other oil chamber side, and the aforementioned tube expansion mechanism 2
2, by pulling back the shaft 24, this collect chuck type tube expansion operation is performed.

By driving the electromagnetic valve and the pressure detection switch as described above, the drive ram 19 and the tube expansion ram 25 are driven, and the aforementioned second tube expansion operation by the collect chuck mechanism 2.3 can be performed in the same manner.

In addition, in the above embodiment, only the method for expanding a pressure tube for a nuclear reactor was explained, but the present invention is not limited to this.
It goes without saying that the same method as described above can be applied to expanding the diameter of various types of pipes.

As described above in the embodiments, according to the present invention, which uses both the rubber tube expansion method and the collect chuck method as a method for expanding pressure pipes, there is no need to cut and remove the ends after expanding the pressure pipes. This makes it possible to effectively use expensive materials, and with the conventional die pushing method, it was necessary to finish the entire surface of the expanded tube (including the taper part) for internal finishing after expanding the tube. There is no need for finishing work on the part expanded by this method, and only the end part to be expanded by the collect chuck method needs to be finished. In this case, the work is easy because the work can be done while visualizing the end part.

Therefore, it is possible to eliminate finishing machining, especially on the inside of pressure pipes after pipe expansion, which is difficult to work on, and the number of man-hours for machining is approximately 1/3 to 1/3 that of conventional methods.
The effect is remarkable when the number of processed pieces is as large as several hundred pieces.

[Brief explanation of the drawing]

Fig. 1 is a schematic sectional view showing an example of an apparatus for carrying out the conventional method, Fig. 2 is a partial sectional view showing a pressure pipe expanding apparatus for carrying out the method of the present invention, and Fig. 3 is a detail of section A in Fig. 2. 4 is a sectional view showing the state in which the collect chuck is used, FIG. 5 is a detailed view of part B in FIG. 4, and FIGS. ■-■ cross section of the figure,
FIG. 7 is a hydraulic flow sheet for the apparatus shown in FIG. 2. 13...Mold, 22...Rubber tube expansion mechanism, 23...
Collection No. 4 El is also 50

Claims (1)

[Claims] 1. After enlarging the diameter of the part other than the tip of the tube with one end inserted into the mold using a rubber tube expansion mechanism inserted into the tube, pull out this rubber tube expansion mechanism, and then place a collect chuck on the unexpanded end of the limb tube. A method for expanding a tube, which comprises inserting a mechanism and expanding the diameter of the unexpanded end until it has the same diameter as the diameter expanded once by the rubber tube expansion method.