JPS5913290B2 - Hydraulic pipe expansion device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION When joining a tube and a tube sheet, the tube is inserted into the tube sheet and the end of the tube is pushed from the inside using ultra-high hydraulic pressure of several thousand atmospheres. This invention relates to a hydraulic pipe expansion device that expands and joins.

Conventionally, many of these types of tube expansion devices mechanically expand the tube ends, but this has the following problems: (1) The mechanism is complicated and it is not easy to operate, and (2) The airtightness of the tube and tube sheet is insufficient. or the degree of adhesion is not sufficient, (3) the inner surface of the pipe may be damaged, (4) the expansion of pipes with large wall thickness relative to the diameter may be insufficient, and (5) all 5 (6) It is difficult to process multiple pieces at the same time.

Recently, in an attempt to overcome these drawbacks, hydraulic pipe expansion devices have been developed.

However, with this hydraulic tube expansion device, the tube expansion head is inserted into the inner surface of the tube end, and the tube end is expanded by the hydraulic pressure injected from the tube expansion head, so there is no liquid tightness between the tube expansion head and the inner surface of the tube end. must be ensured first, but since a hydraulic pressure of several thousand atmospheres is used, it is difficult to maintain a liquid-tight seal between the two, and the seal at the head of the expansion tube is also incomplete, so the tube must be expanded and joined completely. This was a difficult matter. The present invention has an extremely simple structure that can easily withstand ultra-high pressures reaching several thousand atmospheres, and can fully achieve the purpose of pipe expansion and joining.

F0 The configuration will be explained with reference to the drawings. 1 is a liquid tank.

Although the liquid tank 1 is shown in four locations in FIG. 1 for convenience, it is actually one tank. 2 is a filter,
3 is the motor, 4 is the hydraulic horn 25, 5 is the check valve, 6 is the pressure gauge, T is the relief valve, 8 is the 3 position 4
This is a boat switching valve.

These hydraulic pressure generators M are connected to a pressure intensifier N through a flexible hose 9. q is a liquid supply/drainage pipe to the low pressure side N of the pressure intensifier N, q is a liquid replacement pipe to the high pressure side, and 10 is a 30 check valve. 1
Reference numeral 1 denotes a hydraulic tube expansion section, which is connected to the high pressure side of the pressure intensifier N with an ultra-high pressure tube 11'.

In FIG. 2, 12 is the tube expansion head of the hydraulic tube expansion section 11;
Reference numeral 13 denotes a pressure liquid flow hole 35 communicating with the ultra-high pressure tube 11', and this pressure liquid flow hole 13 opens on the outer surface of the tube expansion head 12 at approximately the center thereof, forming an opening surface portion 13' there.

Grooves 18, 18 are formed on the outer peripheral surface of the tube expansion head 12 with the opening surface 13' in between, into which the seal supports 14 and back-up springs 17, 17 (to be described later) are inserted. do. A thin stepped piece 14' of the seal support 14 covers the opening surface 13', and an O-ring 15 is interposed between the thin stepped piece 14' and the opening surface 13'.
The upper surface of the seal support 14 contacts the inner surface of the tube end A, with an O-ring 16 interposed between the two.

The outer walls 1, 9 of the seal support 14 form slopes, and the outer wall 19 contacts the inner wall of the back-up spring 17, which is similarly fitted into the fitting groove 18 of the seal support 14. B
indicates a tube plate.

The effect will be explained.

When the hydraulic pump 4 is driven now, the pressurized fluid enters the low pressure side N' of the pressure booster N by switching the switching valve 8, and generates an extremely high pressure of several thousand atmospheres on the high pressure side N''. It is sent to the hydraulic expansion tube section 11 via the tube 11'.

In this part, the pressure fluid reaches the opening surface 13' through the pressure fluid flow hole 13, where it presses the inner surface of the tube A between the O-rings 16, 16, and the tube A is pressed against the tube plate B. The tube is expanded and the two are joined.

At this time, the O-ring 15 seals off the pressure fluid flowing to the inner surface of the stepped piece 1.4' of the seal support 14.

Then, hydraulic pressure is applied to the inner wall of the stepped piece 14' in the axial direction of the tube expansion head 12, and the outer wall 19 of the seal support 14 presses the back-up spring 17. 19, and its pressure receiving area is small, so the outward pressing force by the stepped piece 14' is dispersed on the outer wall 19, which has a large pressure receiving area. This means that strong force will not be applied. Therefore, the pressing force will not cause the back-up spring 17 to protrude at the corner point p where the back-up spring 17 contacts the tube expansion tube 12.

The effect will be explained. In the present invention, even if an ultra-high hydraulic pressure of several thousand atmospheres is used to join the tube sheet and the tube, there will be no damage between the tube expansion head and the inner surface of the tube end, or between the tube expansion head and the seal support or back-up spring. There is no leakage during the process, and strong pipe expansion and jointing can be performed.

Moreover, at this time, the pressure receiving area of the stepped piece of the seal support is smaller than the area of the outer wall of the support on the back-up spring side, so the pressing force applied to the stepped piece is dispersed on the outer wall. Become.

Therefore, the ring does not protrude from the corner between the ring and the tube expansion head, the tube expansion head can be easily pulled out from the tube end after tube expansion, and it can withstand use for a long period of time. In addition, due to the elastic deformation of the back-up spring due to the appropriate force, the ring and tube body A come into close contact with each other, so that the 0-ring will never protrude outside through the gap, and the 0-ring will be completely liquid-tight. . Once the O-ring protrudes, the ring is damaged and cannot be used thereafter; however, with the present invention, there is no risk of this happening, and the present invention can withstand use for a long period of time.

[Brief explanation of drawings]

FIG. 1 is a front view of the entire hydraulic tube expansion device, and FIG. 2 is a longitudinal side view of the hydraulic tube expansion section. 12...Pipe expansion head, 13...Pressure liquid flow hole, 13'...Opening surface, 14...
Seal support, 14'...Stepped piece, 15,1
6...O ring, 17...Backup spring, A...tube, N...pressure booster.

Claims (1)

[Claims] 1. A pressure fluid flow hole communicating with the pressure intensifier is bored in the tube expansion head, and the hole is opened on the outer surface of the approximately central part of the tube expansion head to form an opening surface on the outer surface, and the opening surface is sandwiched between the two sides of the hole. A fitting groove is provided in the groove, and a seal support and a backup ring are fitted on the outside of the seal support.A thin stepped piece is formed on the seal support, and the opening surface is covered with this stepped piece. A hydraulic pipe expansion device in which an O-ring is interposed between the piece and the opening surface, and the upper surface of the seal support and the inner surface of the tube end are brought into contact via the O-ring.