JPS58138522A - Hot pipe bender - Google Patents

Abstract

PURPOSE:To obtain a titled bender which prevents a bent part from an irregular deformation caused by buckling or wrinkle, etc., by forming the cross sectional shape of a heating coil into a taper shape, and spraying cooling water from both ends of its inner diametral surface to a pipe material to limit the heating width into a small range. CONSTITUTION:A pipe material 2 to be worked is bent, while heating the material 2 by an annular heating coil 1A, by loading a working force to the end surface of material 2 through a rod part 5a by driving a hydraulic cylinder 5, and producing a bending moment at the rear part of material 2 from guide rolls 6 by rotating an arm 8, fixed at its one end, around a pivot 9 set as the center. The cross sectional shape of the coil 1A is formed into a taper shape, tapered from the outer diametral surface 1a to the inner diametral surface 1b, and cold water 4 is sprayed from jetting nozzles 1c, provided to both ends of the inner diametral surface 1b and positioned in the inside of the coil 1A, onto the pipe material 2 to heat it through the narrow heating width 11A by supplying an high frequency electric current from a high frequency oscillator 7.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a hot tube bending machine, and more particularly, to an arm rotation type hot tube bending machine that is aimed at preventing irregular deformation in the bending part of a tube material that is a workpiece. It is related to.

First, a conventional hot tube bending method using an arm rotation method will be explained using FIGS. 1 and 2.

Fig. 1 is a plan cross-sectional view showing a conventional arm rotation type hot pipe bending machine and the pipe material bent by the machine, and Fig. 2 is a schematic diagram showing the vicinity of the heating coil in Fig. 1. FIG.

First, a pipe material 2, which is a workpiece material, is moved between two guide rollers 6 (
The guide roller 6 rotates as the tube 2 moves, and passes through the annular heating coil 1. Further, one end of the tube 2 is fixed to the arm 8, and the other end is attached to the rod portion 5a of the hydraulic cylinder 5. Then, by driving the hydraulic cylinder 5, a machining load is applied to the end surface of the pipe material 2,
Extrude the tube material 2. This allows arm 8 to pivot to pivot 9.
The tube material 2 is bent by rotating at a constant bending radius around .

Here, the bending portion is heated by high frequency induction by the heating coil 1 to which a high frequency current is supplied by the high frequency oscillator 7. The heating coil 1 is hollow, and cooling water 4 for cooling the heating coil 1 is supplied from a cooling water pipe 3 into the interior thereof.

By the way, the heating width 11 of the area heated by the heating coil 1
As shown in Fig. 2, since it is wide (for example, about 5 times the thickness of the pipe material 2),
Irregular deformation portions 10 such as buckling and wrinkles occur on the upper and lower sides in FIGS. 1 and 2, which impairs the appearance of the processed product, and the dimensional accuracy is poor, making it impossible to perform a good bending process.

In particular, if the bending radius is less than about twice the outer diameter of the tube material 2, the irregular deformation will become large, so in order to prevent this, it is necessary to make a thick bend that is more than twice the outer diameter of the tube material 2. There was also the problem that it was necessary to bend the pipe with a radius, which made it impossible to increase the density of the piping equipment.

The present invention eliminates the drawbacks of the above-mentioned conventional techniques, and provides an arm-rotating hot tube bending process that does not cause irregular deformation such as buckling or wrinkles in the bent portion. Its purpose is to provide a bending machine.
If, 1, the feature of the present invention is that an annular heating coil is disposed around the outer periphery of the bent portion of the pipe material, and a high frequency current is supplied to this heating coil to heat the bent portion while rotating the arm. In a hot pipe bending machine that performs pipe bending,
The heating coil is formed into a tapered shape so that its cross-sectional shape becomes narrower from the outer diameter surface toward the inner diameter surface, and cooling water is injected from inside the heating coil toward the pipe material at both ends of the inner diameter surface. This is a hot tube bending machine equipped with injection holes for this purpose.

More details are as follows.

During bending of pipe materials, compressive stress is applied to the inner side of the bend, which causes buckling, wrinkles, etc., and causes defects. In particular, it is necessary that the thickness of the tube material be thin and the bending radius narrow.

Therefore, the present invention cools the pipe material by heating, making the cross-sectional shape of the coil tapered, and injecting cooling water from injection holes provided at both ends of the inner diameter surface, limiting the heating width, and preventing buckling.

This is to prevent irregular deformation such as wrinkles.

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

FIG. 3 is a plan sectional view showing a hot tube bending machine according to an embodiment of the present invention and the tube material bent by the machine, and FIG. 4 shows the vicinity of the heating coil in FIG. FIG.

In FIG. 3, parts with the same numbers as in FIG. 1 are the same parts.

The heating coil IA of this embodiment has a cross-sectional shape on the outer diameter surface 1.
The heating coil I
Injection holes IC for injecting cooling water 4 from the inside of A toward the pipe material 2 are drilled in a distributed manner.

The specific dimensions of this heating coil IA are as follows.

The outer diameter is 210 mm, the width is 20 mm, and the inner diameter is 170 mw.

It has a width of 10 m and tapers from the outer diameter surface 1a to the inner diameter surface 1b. Further, a hole having a diameter of 1 m and an angle of 45° with respect to the axis of the tube material 2 are provided at both ends of the inner diameter surface 1b.

107 injection holes IC with a pitch of about 5M are distributed in the circumferential direction and provided on each side.

Then, a part of the cooling water 4 for cooling the heating coil led from the cooling water pipe 3 into the heating coil IA is transferred to the injection hole IC.
The heating width 11 is
This is to make A narrower.

The hot tube bending machine configured in this way has an outer diameter of 165 mm.
A tube material 2, which is a carbon steel tube for high-temperature piping (STPT42) with a length of 2 m, a plate thickness of 7.1 m, and a length of 5.5 m, is inserted between two guide rollers 6 to support the outer diameter surface. Furthermore, it is passed through the heating coil IA and the end portion is fixed to the arm 8. Here, the bending radius, that is, the distance from the center of the pivot 9 to the center of the tube material 2, is 247.8 m (1 of the outer diameter of the tube material 2).
．． 5 times). After setting the tube material 2 as described above, the bent portion is heated by high frequency induction using the high frequency oscillator 7° and the heating coil IA. Heating to the processing temperature of 85 Or (outer surface temperature), heating width 11A is less than twice the plate thickness (
14.2 mw or less).Adjust the amount of cooling water.

In addition, the output of the high frequency oscillator 7 is 80 kW, and the frequency is 30.
00H2.

Next, with the bending part heated, a working force of 5.4 tons is applied to the end face of the tube 2 by driving the hydraulic cylinder 5, and the arm 8 is pushed out at a rate of 1 visit/second. Rotate. Since the arm 8 rotates around the pivot 9 at a constant radius, a bending moment is generated at the bending portion, allowing the tube material 2 to be bent. By performing this bending process continuously, the rotation angle (bending angle) of arm 8 is 90°.
When the temperature reaches .degree., the pressure in the hydraulic cylinder 5 is released and the output of the high-frequency oscillator 7 is stopped, thereby stopping the heating. With the above steps, the bending process of the tube material 2 is completed.

According to the embodiment described above, it is possible to perform bending with a small radius of 1.5 times the outer diameter of the tube material 2 without causing irregular deformation such as wrinkles or buckling. became.

Along with this, the density of piping equipment can be increased by 30% or more compared to the conventional method.

As described above in detail, according to the present invention, an annular heating coil is disposed around the outer periphery of the bent portion of the pipe material, and while heating the bent portion by supplying a high frequency current to the heating coil, In a hot tube bending machine that performs tube bending using an arm rotation method, the heating coil is formed into a tapered shape so that its cross-sectional shape becomes narrower from the outer diameter surface toward the inner diameter surface, and a heating coil is formed at both ends of the inner diameter surface. Since an injection hole is provided to inject cooling water from inside the heating coil toward the tube material, hot tube bending can be performed without causing irregular deformation such as buckling or wrinkles in the bent portion. It is possible to provide an arm rotation type hot tube bending machine that can perform the following steps.

[Brief explanation of the drawing]

Fig. 1 is a plan cross-sectional view showing a conventional arm rotation type hot pipe bending machine and the pipe material bent by the machine, and Fig. 2 is a schematic diagram showing the vicinity of the heating coil in Fig. 1. FIG. 3 is a plan sectional view showing a hot tube bending machine according to an embodiment of the present invention and a tube material to be bent by the hot tube bending machine, and FIG. FIG. 3 is an enlarged cross-sectional view of a main part showing the vicinity of a heating coil.

Claims (1)

[Claims] 1. Hot tube bending in which an annular heating coil is placed around the outer periphery of the bending section of the tube material, and a high-frequency current is supplied to this heating coil to heat the bending section while bending the tube using an arm rotation method. In the processing machine, the heating coil is formed into a tapered shape so that its cross-sectional shape becomes narrower from the outer diameter surface to the inner diameter surface, and cooling is applied from the inside of the heating coil toward the pipe material at both ends of the inner diameter surface. A hot pipe bending machine characterized by having an injection hole for injecting water.