JPH0479729B2 - - Google Patents

Description

[Detailed Description of the Invention] [Field of Application of the Invention] The present invention relates to an apparatus for manufacturing a branch pipe joint, and in particular,
The present invention relates to a manufacturing device for a branch pipe joint, which is intended to manufacture a branch pipe joint in which the plate thickness of the branch pipe portion is substantially uniform along the circumferential direction.

[Background of the invention]

First, we will start with the conventionally known branch pipe forming method and device (Japanese Patent Application No. 89893/1989,
55171) and the branch pipe joint manufactured thereby.

FIG. 1 is a schematic cross-sectional view showing a conventional branch pipe joint manufacturing apparatus and a main pipe formed thereby, and FIG. 2 is a branch pipe joint manufacturing apparatus according to FIG. 1. 1 is a perspective view showing a branch pipe joint manufactured by.

In Fig. 1, 1 is a main pipe with a prepared hole;
3 is a fixing clamp for fixing both ends of the main pipe 1; 4 is a burring punch having a truncated conical shape related to a burring jig; and 5 is a burring punch for passing a high-frequency current generated by a high-frequency power source (not shown). This is an annular heating coil for high-frequency induction heating the peripheral edge of the prepared hole of the main tube 1, that is, the burring forming part.

To explain the operation of the apparatus for manufacturing a branch pipe joint constructed in this way, first, both ends of the main pipe 1 having a pilot hole bored therein are fixed using the fixing clamps 3, and then the burring punch 4 is inserted into the main pipe. 1 and fix it to the rod 6. Next, a high frequency current is passed through the annular heating coil 5 to heat the burring molded part to a predetermined temperature by high frequency induction. While maintaining this machining temperature, the machining force 7 is applied to the rod 6.
By applying a load and performing burring, the branch pipe portion 2 is formed, and a branch pipe joint is obtained.

However, in the branch pipe joint manufactured in this way, the plate thickness of the branch pipe part 2 differs significantly along the circumferential direction, and in particular, 2a on a cross section including the axis of the main pipe 1 and the axis of the branch pipe part 2. , 2c is thinner, and the plate thickness near points 2b and 2d, which are perpendicular to this, is thicker. Therefore, the above 2a,
The strength near point 2c was weak, and there was a problem with the reliability of the strength. Furthermore, cracks 2e may occur near the points 2a and 2c, which causes defects.

[Purpose of the invention]

The present invention eliminates the drawbacks of the above-mentioned prior art and makes it possible to manufacture a branch pipe joint in which there is no variation in processing force and the plate thickness of the branch pipe portion is substantially uniform along the circumferential direction. The purpose is to provide a manufacturing apparatus for

[Summary of the invention]

The configuration of the branch pipe joint manufacturing apparatus according to the present invention is as follows:
A cooling system equipped with a saddle-shaped heating coil for high-frequency induction heating of the periphery of a pilot hole drilled in the main pipe, and a plurality of nozzles capable of injecting a cooling medium toward the periphery of the pilot hole. a temperature gradient controller capable of controlling the output of the high-frequency current flowing to the heating coil and the flow rate of the cooling medium injected from each nozzle, and a burring jig inserted into the main pipe from the prepared hole. It is equipped with a rod for pulling it out.

[Embodiments of the invention]

Before entering into the description of the embodiments, basic matters related to the present invention will be explained using FIGS. 2 and 3.

FIG. 3 is a processing temperature-deformation resistance diagram showing the relationship between processing temperature and deformation resistance of a carbon steel pipe.

As mentioned above, the branch pipe joint manufactured by the conventional branch pipe joint manufacturing apparatus has the following characteristics (see Fig. 2):
Strain tends to concentrate in the vicinity of points 2a and 2c of the branch pipe portion 2, and the thickness of the plate at points 2a and 2c becomes significantly thinner, posing problems in terms of strength. Therefore, the present invention suppresses the deformation at points 2a and 2c where the plastic deformation is large, and increases the plastic deformation at the points 2b and 2d where the deformation is small, so that the plate thickness of the branch pipe portion 2 is increased in the circumferential direction. It is made to be almost uniform along the length.

Incidentally, the deformation resistance of a carbon steel pipe, which is an example of the material of the main pipe 1, depends on the processing temperature, as shown in FIG. That is, when the processing temperature is low, the deformation resistance is large, whereas when the processing temperature is high, the deformation resistance is small and the amount of plastic deformation is large. Therefore, when forming a branch pipe joint, the amount of plastic deformation at points 2a and 2c can be suppressed by lowering the processing temperature near points 2a and 2c, where strain is concentrated, compared to points 2b and 2d. The deformation at points 2b and 2d can be increased, and the plate thickness of the branch pipe portion can be made almost uniform along the circumferential direction.

Examples will be explained below.

FIG. 4 is a front view showing a branch pipe joint manufacturing apparatus according to an embodiment of the present invention, FIG. 5 is an enlarged cross-sectional view taken along the - arrow in FIG. 4, and FIG. FIG. 2 is a perspective view showing a branch pipe joint manufactured by the branch pipe joint manufacturing apparatus.

The configuration of this embodiment will be explained using FIGS. 4 and 5.

In FIG. 4, the same parts as in FIG. 1 are denoted by the same numbers. As mentioned above, 1 is a main pipe with a prepared hole 1a, 18 is a lower bed on which a fixing clamp 3 is placed and fixed, and a support 17 is erected; , a burring punch 4 inserted into the main tube 1 is placed on the bottom surface of the burring punch 4.
Fix the rod 6 for pulling out from the prepared hole 1a,
A crosshead that can move up and down along the support 17; 15 is an upper bed fixed to the upper end of the support 17; 13 is a hydraulic cylinder fixed to the upper bed 15;
A machining force 20 can be applied to the rod 6 via the crosshead 16 fixed to the lower end of the spindle 13a. Further, this hydraulic cylinder 13 is driven upward by introducing the hydraulic pressure generated in the press operating section 12 through a pipe 14, and when the crosshead 16 comes into contact with a limit switch 19, the upward movement is stopped. Reference numeral 8 denotes a saddle-shaped heating coil that is disposed near the pilot hole 1a of the main pipe 1 and formed so that the distance from the main pipe 1 is almost equal all around the circumference, and a temperature gradient is applied to the heating coil 8. By guiding the high frequency current generated by the controller 11 (details will be described later) through the wiring 8a, the peripheral edge of the prepared hole 1a can be heated by high frequency induction.

Reference numeral 9 denotes a cooling ring to which eight nozzles 10 are attached, which are capable of injecting a mixed fluid 23 of water and air, which is a cooling medium, toward the peripheral edge of the prepared hole 1a. As shown in FIG.
10b, 10bc, 10c, 10cd, 10d, 1
0da, and among these, 10a, 1
0b, 10c, and 10d are the branch pipe portions 2, respectively.
This is the position opposite to points 2a, 2b, 2c, and 2d (see FIG. 2). These 8 nozzles 10
are each independently connected to the temperature gradient controller 11. Further, the cooling ring 9 is fixed to the support column 17 by a fixing fitting 22 attached to a pipe 21 connected thereto.

To explain the temperature gradient controller 11 in detail, the temperature gradient controller 11 is capable of generating a high frequency current to flow into the saddle-shaped heating coil 8 and controlling the output thereof, and is also capable of controlling the output of the high-frequency current flowing to the saddle-shaped heating coil 8. Each nozzle 10 receives a signal from a two-color thermometer (not shown) for detecting processing temperature.
By controlling the flow rate of water and air injected from the holes 2a, 2b, 2c, 2d at the peripheral edge of the pilot hole 1a,
The processing temperature at the point (see FIG. 2) can be automatically adjusted to a preset temperature.

The operation of manufacturing a branch pipe joint from a main pipe using the branch pipe joint manufacturing apparatus configured as described above will be described.

First, both ends of the main pipe 1 having prepared holes 1a bored at predetermined positions are fixed with fixing clamps 3.
A saddle-shaped heating coil 8 is set above the pilot hole 1a and near the periphery. The burring punch 4 is inserted into the main pipe 1, and the burring punch 4 is fixed to a threaded portion (not shown) provided at the tip of the rod 6 by screw fastening to set it.

Strain concentrates on the temperature gradient controller 11 2
Processing temperature near points a and 2c (e.g. 700℃)
is lower than the processing temperature (for example, 900°C) near points 2b and 2d perpendicular to this,
Set a predetermined processing temperature distribution.

Here, when this branch pipe joint manufacturing apparatus is turned on, the entire peripheral edge of the prepared hole 1a is heated by high frequency induction to a temperature higher than the processing temperature by the heating coil 8. Subsequently, a mixed fluid 23 of water and air is injected from the nozzles 10, and each nozzle 1
The injection amount from 0 is controlled based on a signal from the two-color thermometer attached to the nozzle,
The peripheral edge of the prepared hole 1a is forcibly cooled so as to have the set temperature gradient. When this temperature gradient becomes stable, the hydraulic cylinder 13 is driven by the press operating section 12, and the crosshead 16 is raised. Accordingly, a processing force 20 is applied to the rod 6, and burring is performed by the burring punch 4 to form the branch pipe portion 2A. At this time, during the burring process, the relative position of the burring part to the saddle-shaped heating coil 8 changes as the burring punch 4 rises, but the magnetic field for high-frequency induction heating is generated around the saddle-shaped heating coil 8. Because it is spread over a wide area, machining progresses within the magnetic field, and the machining time is short.
The temperature gradient of the processed portion described above can be maintained at its initial state until the processing is completed. In this way, in the present invention,
Since the processing temperature is kept low at points 2a and 2c where strain is concentrated, the deformation resistance in the vicinity increases and plastic deformation can be suppressed.

The burring punch 4 is safely pulled out from the pilot hole 1a, and the crosshead 16 is turned into the limit switch 19.
When it comes into contact with the temperature gradient controller 11, it stops rising.
turns off. When the processed product is taken out after it has cooled down, as shown in Figure 6, the thickness at each point 2a, 2b, 2c, and 2d along the branch pipe section 2A is almost uniform, and there are no cracks. This results in a branch pipe fitting that does not require

Next, a specific example will be described.

A branch pipe section 2A with an inner diameter of 195.7 mm is added to the carbon steel pipe of the main pipe 1 with an outer diameter of 318.5 mmφ, a plate thickness of 10.3 mm, and a flow length of 2 m.
The case of molding will be explained.

The processing temperature-deformation resistance diagram of this carbon steel pipe is as shown in FIG. 3 above.

The conditions for high-frequency induction heating using the saddle-shaped heating coil 8 (inner diameter approximately 260 mmφ) are that the frequency is constant at 2.5 kHz, and the processing temperature is approximately 900°C near 2b and 2d.
The temperature near 2a and 2c perpendicular to each is 700℃
It is. In this way, when there is a temperature difference of 200°C, as is clear from FIG. 3, the deformation resistance is approximately twice as different. In addition, the burring punch 4 has an outer diameter of
It is 195.7mm in shape and has a truncated cone shape with a half apex angle of 30°.
The processing force 20 was approximately 14 ^tf .

When the above-mentioned conditions were set and the carbon steel pipe was burred by the branch pipe joint manufacturing apparatus according to FIG. It was possible to form almost uniform branch pipe joints.

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

(1) Since the plate thickness of the branch pipe portion 2A can be formed almost uniformly, the reliability in terms of strength of the branch pipe joint is improved.

(2) Cracks 2 that conventionally occurred at the tip of the branch pipe section 2
Since it is possible to prevent defects such as e, appearance defects can be significantly reduced.

In addition, in this example, the case where a carbon steel pipe is used as the material of the main pipe 1 has been explained, but
The present invention is applicable not only to carbon steel pipes, but also to the manufacture of branch pipe joints using all metal pipes and alloy pipes, such as stainless steel pipes and alloy steel pipes.

[Effects of the Invention] As described in detail above, according to the present invention, it is possible to manufacture a branch pipe joint in which there is no variation in processing force and the plate thickness of the branch pipe portion is substantially uniform along the circumferential direction. An apparatus for manufacturing a branch pipe joint can be provided.

[Brief explanation of drawings]

FIG. 1 is a schematic cross-sectional view showing a conventional branch pipe joint manufacturing apparatus and a main pipe formed thereby, and FIG. 2 is a branch pipe joint manufacturing apparatus according to FIG. 1. FIG. 3 is a processing temperature-deformation resistance diagram showing the relationship between processing temperature and deformation resistance of carbon steel pipes, and FIG. FIG. 5 is an enlarged cross-sectional view taken along the - arrow in FIG. FIG. 2 is a perspective view showing a branch pipe joint. DESCRIPTION OF SYMBOLS 1... Main pipe, 1a... Pilot hole, 4... Burring punch, 6... Rod, 8... Saddle-shaped heating coil, 9... Cooling ring, 10... Nozzle, 11...
...Temperature gradient controller, 23...Mixed fluid.

Claims (1)

[Claims] 1. A saddle-shaped heating coil for high-frequency induction heating the peripheral edge of a pilot hole drilled in the main pipe and a plurality of nozzles capable of injecting a cooling medium toward the peripheral edge of the pilot hole were installed. a cooling ring, a temperature gradient controller capable of controlling the output of high-frequency current flowing to the heating coil and the flow rate of the cooling medium injected from each nozzle, and a burring jig inserted into the main pipe into the prepared hole. A manufacturing device for a branch pipe joint, characterized in that it is equipped with a rod for pulling it out from the pipe.