JPS59225813A - Method and device for forming branch pipes - Google Patents

Abstract

PURPOSE:To form easily a branch pipe with dimensional accuracy by withdrawing a burring jig inserted in a main pipe while heating the burr forming part of a main pipe by high-frequency induction heating and cooling the other part of said forming part. CONSTITUTION:A main pipe 1 after boring a primary hole is inserted in the inside of a heating coil 12 and is fixed by a clamp 3. A burring jig 4 is inserted into the pipe 1, and cooling water is flowed in the heating coil 12 and is sprayed from cooling water jetting holes 12a, 12b to cool the other part of a burr-forming part 2. A high-frequency current is flowed in the heating coil 12, in this state, to heat the part 2 by high-frequency induction heating. When the temperature of forming part 2 rises to a set temperature, the burring jig 4 is withdrawn from the primary hole of main pipe 1 to form a burred hole thereby completing the formation of a branch pipe.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Application of the Invention] The present invention relates to a method and apparatus for forming a one-branch pipe, and more particularly to a method and apparatus for forming a five-branch pipe for forming a branch pipe with good dimensional accuracy. be.

[Backwear of invention”]

First, a conventional method for forming a branch pipe will be explained.

FIG. 1 is a schematic partial cross-sectional view showing a molding device used for carrying out a conventional method for molding a single branch pipe, and a main pipe molded thereby.

In FIG. 1, numeral 1 denotes a main tube with a prepared hole, and numeral 5 denotes clamps for fixing the main tube for fixing both ends of the main tube 1. 7 is a lower bed on which the clamp 6 for fixing the main pipe is placed and fixed, and on which a support 9 is erected;
8 is an upper bed fixed to the upper end of the support column 9;
! .

This is fixed to the upper bed 8, and a hydraulic cylinder is capable of applying processing force 11 to the spindle 5a for pulling out the burring jig 4 from the subordinate hole.

be. Further, 10 is a gas burner for heating the vicinity of the prepared hole.

In the branch pipe forming apparatus configured as described above, first,
After fixing 17 both ends of the main pipe 1 with pilot holes drilled and installed using the main pipe fixing clamp 5, the burring jig 4 is attached to the main pipe 1.
Insert inside ■2, this.

Place the burring jig 4 on the spindle 1° of the hydraulic cylinder 5.
Set it by fixing it to a. Next, gas burner 1O
2. Therefore, the burring forming part near the pilot hole is heated. The hydraulic cylinder 5 is heated to a predetermined processing temperature.
The processing force 11 for pulling out the burring jig 4 is
By applying a load to the spindle 5a and pulling out the burring jig 4 from the prepared hole, the burring forming part 2 is formed and a desired branch pipe is manufactured.

However, in this way, the branch pipes that were used for farming.

The heating molding part 2 is also heated by heat conduction outside the burring molding part 2.
The peripheral part 2a of bulges out, and the burring-formed lower part 1a becomes '<2. It had become irregularly deformed by being bent and concave. In addition, since the heating method uses the gas burner 10,
Temperature control is difficult, resulting in uneven temperature distribution, making it impossible to uniformly heat the burring molding section 2. others? l) The wall thickness of the burring molded part 2 becomes non-uniform, and in addition to the above-mentioned irregular deformation, there is a drawback that the dimensional accuracy of the branch pipe is poor.

[Purpose of the invention]

An object of the present invention is to provide a method for forming a branch pipe that can eliminate the drawbacks of the prior art described above and form a branch pipe with good dimensional accuracy, and a forming apparatus that can be used directly for carrying out the method. That is.

[Summary of the invention]

The branch pipe forming method according to the present invention has a structure in which a pilot hole is bored at a predetermined position, and a heating coil is arranged around the outer periphery of the pilot hole, and a part of the main tube in the vicinity of the pilot hole is formed by burring. The part is subjected to high-frequency induction heating by the heating coil, and is also subjected to plastic working.

To areas other than the burring molding part that you do not want to prevent.

While injecting a portion of the cooling water that cools the heating coil, the burring jig inserted into the main pipe is pulled out from the prepared hole to form the branch pipe.

It is designed to be molded.

In addition, the configuration of the branch pipe forming apparatus according to the present invention is such that processing force for pulling out the burring jig from the pilot hole of the main pipe in which the pilot hole has been bored is applied to a spindle attached to the burring jig. a hydraulic cylinder disposed on the outer periphery of the main pipe and having an opening through which the burring jig can pass, and which supplies a portion of the t-th cooling water for cooling itself to the main pipe. The heating coil is equipped with a cylindrical heating coil provided with cooling water injection holes for injecting cooling water to areas other than the burring forming part of the tube.

[Embodiments of the invention]

The present invention will be explained below with reference to Examples.

FIG. 2 shows an example of a forming apparatus used for carrying out a method for forming a branch pipe according to an embodiment of the present invention, together with a main pipe formed by the apparatus.

The schematic partial sectional view, FIG. 3, is a sectional view taken along the line ■-■ in FIG. 2.

In each figure, the same numbers as in Figure 1 are given.

are the same parts. Reference numeral 5 denotes a hydraulic pressure capable of applying a machining force 11 to a spindle 5a fixed to the burring jig 4 for pulling out the burring jig 4 from the pilot hole of the main pipe 1 in which a pilot hole has been bored. It is a cylinder. 1
2 is a cylindrical heating coil that is disposed around the outer circumference of the main tube 1 and has an opening 12e through which the burring jig 4 can pass. Cooling water 1 introduced from the cooling water inflow pipe 12b
A cooling water injection hole (details will be described later) for injecting part of the cooling water 13 toward an area other than the burring forming part 2 of the main pipe 1 is drilled, and a cooling water outflow pipe is provided to allow the cooling water 13 to flow out. 12c is installed. The cooling water injection holes are distributed and drilled in a circumferential direction on the lower side of the inner circumference of the heating coil 12,
A cooling water injection hole 12a that can be turned to the main pipe 1 and injects the cooling water 15 in a 90° direction (radial direction of the main pipe 1).
and 12 d of cooling water injection holes which are bored at both ends of the upper inner circumference of the heating coil 12 and can inject the cooling water 13 in a 45° direction with respect to the axis of the main pipe 1. 6 is a high frequency oscillator for supplying high frequency current to the heating coil 12. Also.

A two-color thermometer (not shown) capable of detecting the temperature of the heating portion of the main pipe 1 is integrally attached to the heating coil 12 .

The operation of the branch pipe forming apparatus configured in this way will be explained.

First, the main pipe 1 with a pilot hole drilled therein is passed through the heating coil 12, and the center of the pilot hole is aligned with the center of the spindle 5a of the hydraulic cylinder 5, and both ends of the main pipe 1 are fixed to the main pipe. Fix it with clamp 3.

Then, the burring jig 4 is inserted into the main pipe 1, the hydraulic cylinder 5 is driven to lower the spindle 5a, and the burring jig 4 is fixed to the tip of the spindle 5a for setting.

The set temperature of the two-color thermometer of the zero force heating coil 12 is set to a predetermined temperature, and the hydraulic pressure of the hydraulic cylinder 5 is set using a hydraulic pressure setting cycle (not shown) of the hydraulic cylinder 5.

Here, the cooling water 13 is flowed into the heating coil 12 through the cooling water inlet pipe 12b to cool the heating coil 12, and the cooling water 13 is supplied to the cooling water injection hole 12a.

By injecting from 12b, areas other than the burring forming part 2 where plastic working of the main pipe 1 is not desired.

While the area is water-cooled, the high-frequency oscillator 6 is turned on and a high-frequency current is passed through the heating coil 12 to start high-frequency induction heating of the burring forming part 2 of the main pipe 1.

When the temperature of the burring forming part 2 reaches the set temperature,
A signal is output from a transmitter (not shown) of the two-color thermometer, and is received by a relay switch (not shown) of the hydraulic cylinder 5. Then, the hydraulic cylinder 5 is turned ON, and the spindle 5a is pulled up using the preset hydraulic pressure, thereby applying a machining force 11 to the burring jig 4, and the burring jig 4 is pulled out from the prepared hole. Burring molded. When the spindle 5a moves up by a predetermined stroke and hits an IJ switch (not shown) provided on the upper bed 8, the movement of the spindle 5a and the drive of the hydraulic cylinder 5 are stopped, and the high frequency oscillator 6, the generation of high frequency current is stopped and the forming of the branch pipe is completed.

Thereafter, after the molded product has cooled, the supply of cooling water 13 is stopped, and the burring-formed main pipe 1, ie, the branch pipe, is removed.

Next, a specific example will be described.

Main pipe 1 has an outer diameter of 76.5 wn pi and a plate thickness of 5.2
tJaRn A carbon steel pipe with a length of 500wn and the inner diameter of one branch part is 50mmφ.

The case of forming a branch pipe will be explained.

The conditions for high-frequency induction heating by the heating coil 12 are a frequency of 5 kHz, an output of 15 kW, a heating temperature of 850, and a set oil pressure of the hydraulic cylinder 5 of 2 sKpl/cJ (since the cylinder area is 785-, the processing force 11 of 148 tons is (can be loaded). Also, the cooling water 15 is about 401! /m
The flow rate was set to in.

When the above-mentioned conditions were set and the carbon steel pipe was burred using the branch pipe forming apparatus shown in FIG. But <2. It was possible to form a branch pipe without any irregular deformation such as concave shape.

According to the embodiment described above, there are the following effects.

(1) The burring molding part 2 is heated by high frequency induction.

Since the surrounding area is cooled with cooling water 15 to prevent heat from being conducted to areas other than the burring forming part, the wall thickness of the burring forming part 2 becomes uniform and there is no irregular deformation.
It is possible to form branch pipes with good dimensional accuracy1.
A method and apparatus for forming a branch pipe can be provided.

(2) Since the burring forming part 2 is heated by high frequency induction heating, the temperature rise rate is fast and the heating time can be shortened. As a result, the molding time is shorter than that of the conventional gas burner.
The time can be reduced by about 20% compared to when heating is performed. Furthermore, since heating time can be shortened, -
.

Another advantage is that the oxide film can be reduced.

〔Effect of the invention〕

According to the present invention as described in detail above.

Branch pipes with good dimensional accuracy can be formed:.

A method for forming a branch pipe and a forming apparatus directly used for carrying out the method can be provided.

[Brief explanation of the drawing]

FIG. 1 is a schematic partial cross-sectional view showing a forming apparatus used for carrying out a conventional method for forming one branch pipe, and a main tube formed by this apparatus, and FIG. FIG. 5 is a schematic partial cross-sectional view showing an example of a molding device used to carry out the method for molding a single branch pipe according to the embodiment, and a main pipe formed by the same, and FIG. It is a sectional view taken along the direction m. 136. Mother tube, 2-8. Burring molding part, 411. Burring jig, 5... Hydraulic cylinder, 5a... Spindle, 6... High frequency oscillator, 11... Machining force, 1
2... Heating coil, 12a, 12d... Cooling water injection hole, 12e... Opening, 15... Cooling water. Figure 1 Figure 2

Claims (1)

[Scope of Claims] 1. A pilot hole is drilled at a predetermined position, and a heating coil is arranged around the outer periphery of the pilot hole. The burr soda was inserted into the main tube while injecting a portion of the cooling water for cooling the heating coil to an area other than the burring forming part. A method for forming a branch pipe, characterized in that the branch pipe is formed by pulling the main pipe out of the pilot hole. 2. To pull out the burring jig from the pilot hole of the main pipe in which the pilot hole has been bored. a hydraulic cylinder capable of applying a machining force of 1 to a spindle attached to the burring jig;
It has an opening disposed on the outer periphery of the main pipe, through which the burring jig can pass, and a part of the cooling water for cooling the main pipe is directed to an area other than the burring forming part of the main pipe. 1. A branch pipe forming device characterized by comprising a cylindrical heating coil having a cooling water injection hole for spraying water toward the target.