JPH0671346A - Cooling device in heat bending device of metallic tube - Google Patents

Abstract

PURPOSE:To heat a metallic tube all over the periphery at a uniform temperature by reducing ejection of boiled cooling water to a heating coil part when the metallic tube is heated inductively locally, the heated part is deformed by rotation of a bending arm, then, the heated part is cooled by the cooling water. CONSTITUTION:A pan 15 where the metallic tube 2 passes through its middle and flowing water holes 15a having gaps between this metallic tube 2 and the pan are formed is arranged horizontally near the lower part of a high frequency coil 9. The cooling water is lowered from the flowing water holes 15 of the pan 15 aiming at the metallic tube 2.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a cooling device in a heating and bending apparatus for bending a metal tube with a bending arm while inductively heating it with a high frequency heating coil.

[0002]

2. Description of the Related Art Conventionally, as a device for bending a metal pipe,
A feeding device for vertically arranging a metal tube and feeding it in its longitudinal direction, an annular high-frequency heating coil horizontally arranged so as to inductively heat a part of the metal tube, and the same position as the high-frequency heating coil in the feeding direction. A bending arm that rotates around a position separated by a bending radius from the metal pipe, and a clamp that is fixed to the bending arm to grip the metal pipe, and the metal pipe is fed by a feeding device. There is an apparatus that deforms the induction heating portion of a metal tube by rotation to perform bending (for example, Japanese Patent Laid-Open No. 3-230819).
Issue).

The cooling device in the apparatus is provided with a water tank below the high frequency heating coil, and the cooling water is supplied to the water tank.
The water surface is stretched so as to be close to the heating part, and the metal tube after heating and bending is immersed in the water to be cooled.

[0004]

By the way, when a metal tube is bent by the above-mentioned induction heating method,
When it is desired to reduce the bending radius R, for example, when the pipe diameter is D and R / D = 1, the size of the gap between the water surface of the cooling water and the high frequency heating coil needs to be narrowed (3 mm or less).

However, in the conventional cooling method, if the size of the gap between the water surface and the high frequency heating coil is narrowed, when the heated portion of the metal tube enters the cooling water, the cooling water boils and the high frequency heating is performed. There is a concern that it may blow up to the coil part, hit the metal pipe of the heating part, cause an imbalance in the heating temperature, and buckle the metal pipe.

Therefore, there is a problem in this cooling method for bending a metal tube with a small radius of R / D = 1.
Further, for example, a heat insulating material may be interposed between the inner and outer pipes.
When the layer structure pipe is cooled by immersing it in cooling water as described above,
In the case where the inner pipe and the outer pipe are not watertightly sealed, there is a problem that cooling water penetrates between the inner and outer pipes and the performance of the heat insulating material is deteriorated.

Therefore, the present invention aims to propose a cooling device which does not have such a problem.

[0008]

In order to solve the above-mentioned problems, the present invention provides a feeding device (1) for arranging a metal pipe (2) vertically and feeding it in its longitudinal direction, and a part of the metal pipe. An annular high frequency heating coil (9) horizontally arranged for induction heating, and a bending arm (5) which rotates about a position separated from the metal tube by a bending radius at substantially the same position as the high frequency heating coil in the feeding direction. When,
A clamp (7) fixed to the bending arm for gripping the metal pipe is provided, and the metal pipe (2) is fed by the feeding device (1), so that the bending arm (5) rotates to induce induction heating of the metal pipe. In which the portion is deformed and bent, the metal pipe (2) passes through the center, and a saucer having a running water hole having a slight gap with the outer peripheral surface of the metal pipe (2) is formed. (15)
Is placed horizontally in the vicinity of the lower part of the high frequency coil (9) to supply the cooling water (W) to the tray (15).

[0009]

When the required amount of cooling water (W) is supplied to the receiving tray (15), the cooling water flows down from the flowing water hole (15a) formed along the outer peripheral surface of the metal pipe (2), and the metal immediately after heating is heated. Hit the tube (2) and cool its heated part.

At this time, the cooling water boils, but since it continuously drops due to gravity, it hardly blows up, and
The presence of the saucer (15) prevents a part of the boiled water from being blown up to the high-frequency heating coil (9) part and the heating part of the metal tube (2).

Therefore, the entire circumference of the metal tube (2) can be uniformly heated at a predetermined temperature.

[0012]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will now be described based on the embodiments shown in the drawings. In FIG. 1, reference numeral 1 denotes a feeder for holding a metal tube 2 to be bent in a vertical posture by a chuck 3 and sending the metal tube 2 downward, which is operated by a hydraulic cylinder or the like.

Reference numeral 4 denotes a guide roller for feeding the metal tube 2 downward in a vertical posture. A plurality of guide rollers (four in the figure) are provided on a machine body (not shown) so as to rotate while contacting the passing metal tube 2. Reference numeral 5 denotes a bending arm that rotates around a rotating shaft 6 provided on a machine body (not shown), and the rotating shaft 6 has a bending radius of the metal pipe 2 at the side of the position where the metal pipe 2 is bent. It is provided away from the heart.

Reference numeral 7 denotes a clamp, which is a lower end portion of the metal tube 2 in a vertical posture in a state before bending as shown in FIG. 1, that is, a lower end portion of the metal tube 2 projecting slightly below the bending position B of the metal tube 2. It is provided integrally with the bending arm 5 so as to grip. The clamp 7 is divided into left and right parts so that the metal pipe 2 can be grasped from both sides, and the metal pipe 2 is lightly held so that the metal pipe 2 can slide.

Reference numeral 8 denotes a stopper, which is moved forward and backward in the left-right direction in FIG. 1 by a hydraulic cylinder 8a. The clamp 7 of the bending arm 5 is made horizontal as shown in FIG. 1 and the stopper 8 is moved forward. As a result, the stopper 8 is locked to the lower surface of the clamp 7,
The clamp 7 is held in a horizontal posture.

Further, the upper surface of the front portion which is the locking surface of the stopper 8 is formed as an inclined surface 8b whose front is inclined downward, and by gradually retracting the stopper 8, the bending arm 5 is gradually lowered. It is designed to rotate to.

Reference numeral 9 denotes a high frequency heating coil (hereinafter referred to as a heating coil), which is adapted to induction-heat the metal tube 2 by supplying a high frequency current from a high frequency oscillator (not shown).

Reference numeral 10 is a guide roller provided in the heating coil 9. The heating coil 9 and the guide roller 10 will be described in detail with reference to FIGS.

As shown in FIG. 2, the heating coil 9 is formed in an annular shape with ends which are partially separated, and its inner diameter is, as shown in FIG. 3, between the outer peripheral surface of the metal tube 2 passing therethrough. Is set so that a slight gap D ₁ is generated. Furthermore, as shown in FIGS. 3 and 6, the vertical cross-sectional shape is such that the vertical width L ₁ of the inner end surface 9a thereof is narrow, and the upper surface 9b facing outward from the inner end thereof has a slope in which the inner end side descends. Is formed on the surface.

The narrower the vertical width of the inner end surface 9a is, and the smaller the gap between the inner end surface 9a and the outer peripheral surface 2 of the metal tube 2, the narrower the induction heating width of the metal tube 2 in the axial direction becomes. Since it can perform various heating, the above-mentioned gap D ₁ and the vertical width L of the inner end surface 9a
₁ is narrow.

As shown in FIG. 2, an end-shaped annular cooling pipe 11 separated at the same position as the heating coil 9 is fixedly provided on the outer peripheral portion of the upper surface of the heating coil 9. A holding plate 12 made of an insulating material is fixed to the outer periphery of the cooling pipe 11 by a connecting member 13.

The heating coil is, as shown in FIG.
It may be formed by projecting a thin copper plate from the cooling pipe 11. By using such a thin plate, the vertical width L ₁ of the inner end surface 9a can be narrowed.

The holding plate 12 is slidably mounted and held on a pedestal 14 fixed to the machine body so that it can be freely started in the front-rear and left-right directions. As shown in FIG. 5, the guide roller 10 is rotatably supported by a support arm 10a fixed to the upper surface of the holding plate 12 of the heating coil 9, and a part of the peripheral surface of the guide roller 10 is a metal tube. It comes into contact with the outer peripheral surface of No. 2.

The guide rollers 10 are installed at three equal intervals in the circumferential direction of the metal tube 2, and guide the metal tube 2 so that the axis X of the metal tube 2 coincides with the center of the annular heating coil 9. keeping.

As a result, a small gap D ₁ between the inner end surface 9a of the heating coil 9 and the outer peripheral surface of the metal tube 2 is uniformly maintained over the entire circumference. Referring again to FIG. 1, reference numeral 15 denotes a pan for water or a cooling liquid (hereinafter referred to as water), which is the heating coil 9
It is horizontally arranged in the vicinity of the lower part of and is fixed to an airframe (not shown). The central portion of the tray 15 is shown in FIGS.
As shown in FIG. 5, a water flow hole 15a is formed, and the water flow hole 15a is formed.
Is the center X of the metal tube 2 penetrating the water flow hole 15a.
And a gap D ₂ between the inner diameter of the water flow hole 15a and the outer diameter of the metal tube 2 is set so as to hit the outer peripheral surface of the metal tube 2 when water falls.

Reference numeral 16 is a water supply pipe for supplying water onto the tray 15. The metal pipe 2 to be bent may be a single pipe, or may be a three-layer structure pipe as shown in FIGS. 12 and 13.

The three-layer structure pipe shown in FIG. 12 is a heat insulating member made of a metal inner pipe 16 having a bellows-like bellows portion 16a to be bent and a ceramic wool wound around the outer periphery of the inner pipe 16. Material (or sound insulation material) 17 and the heat insulating material 1
7, and an outer tube 18 made of metal provided on the outer circumference. Further, one ends 19 of the inner and outer pipes 16 and 18 are seam-welded to each other, and the other end 20 welds and fixes a wire net ring 21 to the inner pipe 16, and contracts the outer pipe 18 to the outer periphery thereof to make soft contact. I am doing it.

The bellows portion 16a is formed in a wavy shape in the axial direction of the inner tube 16, and the peaks and valleys are formed over the entire circumference. The three-layer structure pipe shown in FIG. 13 is formed by forming the bellows portion 16a only on the bending direction side of the inner pipe 16, and forms the peaks and valleys of the bellows portion 16a as shown in FIG. The center O'of the circle is eccentric downward from the axis O of the inner pipe 16. Other structures are similar to those of the three-layer structure pipe of FIG.

Next, the bending method will be described.
The pipe bent by the effect of the induction heating of the heating coil 9 is the outer pipe 18 in the above-mentioned three-layer structure pipe, which is the same as bending a single metal pipe.
A method of bending the metal tube 2 including the tube 8 and the single tube will be described.

First, as shown in FIG. 1, the bending arm 5 is placed in a posture in which the clamp 7 is horizontal, and the stopper 8 is locked to the lower surface of the clamp 7 to hold the clamp 7 in the horizontal posture. To do.

Further, the metal tube 2 is supported by a guide roller 4 in a vertical posture and movably downward, the upper end of the metal tube 2 is held by the chuck 3 of the feeding device 1, and the lower end of the metal tube 2 is
It is inserted between a plurality of guide rollers 10 and the heating coil 9, and the lower end is fitted into the clamp 7 of the bending arm 5 so that the metal tube 2 is slidably and lightly held.

Further, the required amount of water W is continuously supplied onto the pan 15.
Supply to. Next, from the high frequency oscillator to the heating coil 9,
Energize high frequency current. By this energization, the metal tube 2 is guided
Although it is heated, the inner end surface 9a of the heating coil 9 is
Width L ₁Is formed in a narrow shape and is a gap with the outer peripheral surface of the metal tube 2.
D₁The metal tube 2 is locally
Specifically, that is, extremely short in the axial direction of the metal tube 2.
It is induction-heated and softened in the width.

After this heating, the feeding device 1 is operated to feed the metal tube 2 downward. At the initial stage of this delivery, the stopper 8 is still in the engaged state, and the bending arm 5 does not rotate. Therefore, the lower end of the metal tube 2 is
It slides in the clamp 7 from the position B in FIG. 1 and moves slightly downward to the position C in FIG. During this downward movement, the metal coil 2 is induction-heated by the heating coil 9, and is heated and fed until the start of bending thereafter.

Then, a predetermined amount, for example, several tens of millimeters of metal tube 2
The stopper 8 is gradually moved in the unwinding direction from the time point when is moved downward. By this movement of the stopper 8 in the unwinding direction, the bending arm 7 can be rotated downward by the inclined surface 8a thereof, and by the downward movement of the metal tube 2 by the feeding device 1,
The venting arm 7 gradually rotates clockwise in the drawing. Due to this rotation, a bending moment acts on the metal tube 2, and the bending moment is concentrated on the heating portion where the deformation resistance is the lowest due to induction heating, and the heating portion is bent and deformed.

At this time, since the metal tube 2 is heated and fed to the bending start point as described above, no defect such as a bump or an internal sink mark is generated at the bending start point of the metal tube 2. That is, when the bending of the metal tube 2 is started at the same time as the heating of the metal tube 2, the heating range in the axial direction of the metal tube 2 is sharply bent by the bending start moment in a narrow state, so that as shown in FIG. A hump 22 due to buckling is generated on the inside of the bending start point D in FIG.
Occurs. On the other hand, when the heating feed is performed by the time when the bending is started as described above, when the bending is started, as shown in FIG.
As shown in FIG. 1, since the part E before the bending start point D is heated for several tens of millimeters, the expansion and contraction action due to the bending of the metal tube 2 is dispersed in the heating part of a long distance. Therefore, as shown in FIG. 11, a bent tube having no defective portion such as a bump or a sink mark at the bending start point D can be formed.

Next, when the stopper 8 further moves in the unwinding direction and is disengaged from the clamp 7, the bending arm 5 is in a free rotation state, and the bending arm 5 moves downward as the feeding device 1 moves downward. While holding the lower end of the, rotate clockwise in the figure.

By the downward movement of the metal tube 2, the induction heating section by the heating coil 9 also moves, and the bending moment by the bending arm 5 is applied to the metal tube 2, so that the metal tube 2 has the lowest deformation resistance. The heating section is bent while being bent, and is bent as shown in FIG.

Further, the water W supplied onto the tray 15 hits the entire peripheral surface of the metal tube 2 through the water flow hole 15a and flows down. At the time of this bending, the induction heating part by the heating coil has a narrow width, and the pan 15 is provided close to the heating coil 9, and the heating part is cooled immediately after the heating so that the deformation resistance is reduced. By returning to the strength of, the deformation of only the narrow heating part will be continuously performed, even if the thin metal tube, buckling does not occur in the bent part,
In addition, flatness due to bending is suppressed, and a curved tube with good roundness can be obtained. Furthermore, the structure after deformation is also stable.

SUS430MT was used for the metal tube 2, its plate thickness was 1.5 mm, its outer diameter D was 60.5 mm, and its bend R was 60.5 mm (R / D = 1).
The vertical width L ₁ of the inner end surface 9a of the above is set to 1.0 mm, the gap D ₁ between the inner end surface 9a and the outer peripheral surface of the metal tube 2 is set to 1.25 mm, and the metal tube 2 is induction heated to about 800 to 900 ° C. When the metal tube was bent, the buckling did not occur in the metal tube, and the flatness was calculated according to the following equation (1), and it was about 1 to 2%.

Flatness = (A−B) / D × 100 (1) Here, A and B are the maximum outer diameter and the minimum outer diameter of the metal tube 2, as shown in FIG.

Therefore, according to this embodiment, a thin metal tube is used without buckling and the flatness is about 1 to 2%.
In the range of, bending can be performed with a small bending radius of R / D = 1.

Further, when the water falls from the water flow hole 15a, the water hits the outer surface of the heated metal tube 2 and boils, but since the water continuously falls downward due to gravity, it hardly blows up. Therefore, it is possible to suppress the occurrence of heating imbalance due to the water blowing up to the heating coil 9 and cooling the heating portion of the metal tube 2.

Therefore, the heating is constant over the entire circumference of the metal tube 2, and stable bending is possible. Further, in the case where the upper surface 9b of the heating coil 9 is inclined as shown in FIG. 6, when the boiling water collects on the upper surface 9b, it flows down by the inclined surface and is discharged from the water flow hole 15a.

Next, the case of bending the three-layer structure pipe shown in FIG. 12 will be described. When the outer pipe 18 in the portion where the bellows portion 16a of the inner pipe 16 is located is heated and bent as described above, the bending moment acts on the inner pipe 16 due to the rotation of the bending arm 5. At this time, the rigidity of the bellows portion 16 of the inner pipe 16 is significantly lower than that of the straight pipe state, so that the inner side A, which is the bending center side of the bellows portion 16a, easily contracts and the outer side B, as shown in FIG. Easily extends, and the inner tube 16 easily bends following the bending of the outer tube 18.

Therefore, even if the heat insulating material 17, which is a soft material, is interposed between the inner and outer pipes 16 and 18, the inner pipe 16 is bent almost as cold-worked and has a flat bent shape without flattening.

Also, when the three-layer structure pipe as shown in FIG. 13 is bent by heating, it bends as shown in FIG.
As in the case of the three-layer structure pipe shown in FIG. 12, it has a clean bent shape. Further, when the metal pipe 2 (also for a three-layer structure pipe) laterally shakes during the heating bending process, each guide roller 10 in contact with the metal pipe 2 maintains the contact state and the metal pipe 2 Follow 2 and move the same amount in the same direction. Therefore, the heating coil 9 integrally provided with the guide roller 10 also moves, and the inner end surface 9a of the heating coil 9 is also moved.
The gap D ₁ between the metal pipe 2 and the outer peripheral surface of the metal pipe 2 does not change even if the metal pipe 2 shakes laterally, and is held uniformly over the entire circumference.

[0047]

As described above, according to the present invention, since the blowing of the cooling water to the high frequency heating coil and the heating portion of the metal tube is suppressed, the entire circumference of the metal tube is uniformly heated at a predetermined temperature. The bending process can be performed stably.

Furthermore, the fact that the blowing up of the cooling water is small means that
The surface of the cooling water can be brought close to the high frequency heating coil. This can cope with bending of a thin-walled metal tube that requires cooling immediately after heating and bending, and a thin-walled metal tube can be bent cleanly at a small radius of R / D = 1 without buckling or the like. be able to.

Further, since the cooling water does not penetrate into the metal pipe, when bending a three-layer structure pipe having an insulating material inside the inner and outer pipes, even if the inner and outer pipes are not watertightly sealed, The cooling water does not enter, and the performance of the heat insulating material is not deteriorated.

[Brief description of drawings]

FIG. 1 is a partial cross-sectional side view showing an embodiment of the present invention.

FIG. 2 is a plan view of the heating unit.

3 is a cross-sectional view taken along the line AA in FIG.

FIG. 4 is a sectional view taken along line BB in FIG.

5 is a cross-sectional view taken along the line CC of FIG.

FIG. 6 is an enlarged side sectional view of a high frequency heating coil.

FIG. 7 is a plan view of a saucer for water.

8 is a side view with a partial cross section showing a state where the metal pipe is slightly lowered from the state of FIG.

9 is a partial cross-sectional side view showing a state in which the metal pipe is sent out from the state of FIG. 8 and bent.

FIG. 10 is a side sectional view showing a bent state of a metal tube by a conventional bending process.

FIG. 11 is a side sectional view showing a bent state of a metal pipe bent according to the present invention.

12A and 12B show a three-layer structure pipe to be bent according to the present invention, where FIG. 12A is a side sectional view and FIG. 12B is a front sectional view.

FIG. 13 is a view showing another three-layer structure pipe,
(A) is a side sectional view, (b) is a front sectional view.

FIG. 14 is a side sectional view showing a bent state of the three-layer structure pipe shown in FIG.

15 is a side sectional view showing a bent state of the three-layer structure pipe shown in FIG.

FIG. 16 is a diagram for explaining flatness.

FIG. 17 is a side sectional view showing another example of the high frequency heating coil.

[Explanation of symbols]

 1 Feeding Device 2 Metal Tube 5 Bending Arm 7 Clamp 9 High Frequency Heating Coil 15 Saucepan 15a Flowing Water Hole 16 Cooling Water Supply Pipe W Cooling Water

Claims (1)

[Claims] 1. A feeding device for vertically arranging a metal tube and feeding it in its longitudinal direction, an annular high-frequency heating coil horizontally arranged for induction heating a part of the metal tube, and high-frequency heating in the feeding direction. A bending arm that rotates around a position separated from the metal pipe by a bending radius at substantially the same position as the coil, and a clamp that is fixed to the bending arm and holds the metal pipe, and the metal pipe is fed by a feeding device. By this, the induction heating part of the metal tube is deformed and bent by the rotation of the bending arm. The metal tube passes through the center and there is a slight gap between the metal tube and the outer peripheral surface. A saucer having a water flow hole is horizontally arranged near the lower part of the high-frequency heating coil so that cooling water is supplied to the saucer. Cooling device in the heating bending apparatus of a metal tube, characterized in that the.