JPS597429A - Manufacture of spiral pipe - Google Patents

Abstract

PURPOSE:To form efficiently spirals to the overall length or a part of a metallic pipe, by forming electromagnetically an important part of the metallic pipe into which a core lever having a spiral die in its tip is inserted, in a cylindrical electromagnetic coil, and rotting and moving the die. CONSTITUTION:A part to be formed spirally, of a metallic pipe blank material 1 is inserted into a cylindrical electromagnetic coil 2 for electromagnetic forming, also a core lever 3 is inserted into the pipe 1, and a spiral die 4 of its tip is positioned in a state that it is loosely fitted into the inside of the coil 2. Subsequently, electric energy of high voltage is allowed to flow to the coil 2 for a short time. As a result, a magnetic field of high density is generated between the coil 2 and the pipe 1, and the important part of the pipe 1 is compressed by its repulsion force is adhered closely to the die 4, and is formed to a spiral shape. After forming, the pipe 1 is fed out while rotating the core lever 3 in reverse to the spiral direction. In this case, when an unworked part of the pipe 1 is positioned between the coil 2 and the die 4, and the same working is repeated, continuous spirals 1a of desired length can be formed.

Description

[Detailed description of the invention] Conventionally, one method is usually used to continuously manufacture spiral tubes.

As shown in Figure 1, the long strip (A) is made of e material,
A large number of rollers (B) e are sent out in a certain direction, gradually rolling them into a cylindrical shape and seam welding (C) f, thereby forming a tube body (D), and adding the necessary shapes to the tip. Insert a male threaded die (E) with a diameter of By rotating the tube in the opposite direction, the diameter of the tube (D) and die (E) was expanded to form a spiral protrusion (G).

However, in this case, rotate the upper rod (F) e and move the tube body (
In order to expand the diameter to D)', considerable force is required, and the work must be done by heating and softening the tube 1 (D), which is time consuming and has the disadvantage of slow processing speed.

Further, since the tube body (D) is seam welded, the wall thickness is not uniform, the strength is unstable, and the appearance is not good.

Furthermore, according to such a method, it is impossible to attach a spiral protrusion to only a part of the tube body; 1. If such an article is required, a separately manufactured This requires welding the spiral tube, which is extremely inefficient.

The method of the present invention can substantially eliminate all of the drawbacks of the conventional spiral tube manufacturing method described above, and will be described below with reference to the drawings.

In the present invention, as shown in FIG. 2, it is used as a material for a metal tube fll' of a required diameter.

Insert the important point of this metal tube t1), that is, the part that you want to form into a spiral shape, into the cylindrical electromagnetic coil (2) for electromagnetic forming, and insert the entire part (3) into the metal tube (1). The q-spiral die (4) at its tip is loosely fitted inside the cylindrical electromagnetic coil (2).

That is, the diameter of the die (4) is smaller than the inner diameter of the & straight pipe (1).

In this state, all of the high voltage electrical energy stored in a capacitor (not shown) is passed through the cylindrical electromagnetic coil (2) for a short period of time.

Then, a high-density magnetic field is generated between the coil (2) and the metal tube (1).
The repulsive force generated between the metal tube (1) compresses important parts of the metal tube (1), brings it into close contact with the die (4), and forms it into a helical shape.

After forming, the metal tube (1) is sent out while rotating in the opposite direction to the helical direction of the die (4), and the unprocessed part is connected to the electromagnetic coil (2) and the die (4). ) and repeat the same process.

In this way, the spiral (1a) can be efficiently applied over the entire length of the metal tube (1).

If it is desired to connect a spiral tube to another straight tube of a slightly larger diameter, it is convenient if the straight tube is integrally connected to one or both ends of the spiral tube.

To manufacture something like this, as shown in Figure 6,
Leave the entire unprocessed part (1b) between the already formed spiral part (1a) and the part where the spiral part is to be formed next, and after the forming is completed, place the unprocessed part (1b) in the appropriate position. Just cut it at .

Note that if a highly conductive material such as copper is used as the metal tube +1), the processing efficiency will be further improved.

[Brief explanation of drawings]

FIG. 1 is a partially longitudinal front view for explaining a conventional method for manufacturing a spiral tube, and FIG. 2 is a longitudinal front view for explaining a procedure for manufacturing a continuous spiral tube according to the present invention. FIG. 6 is a longitudinal sectional front view for explaining the procedure for manufacturing the discontinuous spiral tube. fi+ Metal tube (1a) Spiral part (1b)
Unprocessed part (2) Electromagnetic coil (3) Core rod
(4) Die 130-

Claims (1)

[Claims] fil Insert key points of a metal tube into a cylindrical electromagnetic coil for electromagnetic forming, and insert an upper rod having a spiral die at the tip into the metal tube. A die is positioned inside the electromagnetic coil. In this state, by passing high-voltage electrical energy through the electromagnetic coil, the repulsive force due to the high-density magnetic field generated between the coil and the metal tube is applied. The key points of the metal tube are brought into close contact with the die and formed into a spiral shape, and then the upper rod is rotated in the opposite direction to the spiral direction of the die, and the die is moved from the forming part of the metal tube. Characteristic manufacturing method of spiral tube. (2) The unprocessed portion of the metal tube is placed between the electromagnetic coil and the die by transferring the metal tube υ while rotating the die, and the same processing is repeated. The method described in section 11). (3) Cut key points of the unprocessed part so that a required length of unprocessed part remains between the already formed spiral part and the part where the next spiral part is to be formed. A method according to claim 2, characterized in that the method is located between an electromagnetic coil and a die.