JPH05261446A - Device for bending tube - Google Patents

Abstract

PURPOSE:To improve the ellipticity of a bending part and to prevent the reduction of the thickness in the bending part, in reference to the bending work of a tube. CONSTITUTION:The device is provided with a bender 1 for which a groove abutting on the outer periphery of the tube 4 is formed and which is arranged freely rotatably; a first pair of clamps 3a, 3b which is arranged in the proximity of the bender 1 and by which the tube is clamped; a rotary mechanism by which the first pair of clamps 3a, 3b is rotated in the bending direction of the tube 4; a second pair of clamps 13a, 13b by which the tube 4 is clamped at the time of the bending operation of the tube 4 through the rotary mechanism; a pusher mechanism 15a, 15b by which the tube 4 is pushed from behind to the side of the first pair of clamps 3a, 3b; and a block 10 which is for preventing buckling of the tube, is abutted on the bender 1 near the tube 4 and is arranged on the side of the pushing mechanism 15a, 15b.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a pipe bending device, and more particularly to a pipe bending device used for a heat exchanger such as a reheater, a economizer, a superheater, a water wall, or a heat transfer pipe. The present invention relates to a pipe bending apparatus suitable for reducing the wall thickness of the bent portion and improving the ellipticity.

[0002]

2. Description of the Related Art A pipe used in a heat exchange device has various bent portions. As a pipe bending device for forming such a bent portion of the pipe, a pipe shown in FIG. The device shown is used.

This pipe bending apparatus is provided with a bending die 1, which is operated in the vicinity of the bending die 1 by a hydraulic cylinder 2 to form a pipe 4
It is provided with clamps 3a and 3b for gripping. When bending the pipe 4, the clamp 3 is inserted through the hydraulic cylinder 2.
The pipe 4 is gripped by a and 3b, and the clamps 3a and 3b are rotated in the direction indicated by the arrow in the figure through a mechanism (not shown).

When the tube 4 is bent by such a pulling type tube bending apparatus, the ellipticity of the bent portion of the tube 4 is extremely deteriorated. Therefore, as shown in FIG. Gold 5 is placed. The cored bar 5 is connected to a link 7 via a bolt 6, and the link 7 is connected to a hydraulic cylinder 8.

When the pipe 4 is bent, the hydraulic cylinder 8 is operated to insert the cored bar 5 up to near the bent portion of the pipe 4, and when the pipe 4 is bent, the surface of the cored bar 5 is bent when the pipe 4 is bent. It is designed to prevent deformation.

[0006]

However, since the inner wall surface of the pipe slides on the outer peripheral surface of the cored bar 5 outside the bent portion of the pipe 4,
There was a phenomenon that the wall thickness became thin. Therefore, when manufacturing the pipe 4, the pipe 4 having a large wall thickness is expected in consideration of the decrease in the wall thickness.
Need to be manufactured. In this case, if only the bent portion of the pipe 4 has a thick structure, two butt welds will occur,
If the entire thickness of one tube is increased, the weight of the unit increases.

As described above, conventionally, since the bending is mainly performed to improve the ellipticity of the bent portion of the pipe 4, it is unavoidable that the thickness of the bent portion of the pipe 4 is reduced, and the entire pipe is Means to make it thick were taken.

An object of the present invention is to solve the above-mentioned problems of the prior art, to improve the ellipticity of the bent portion of the pipe when bending the pipe, and to prevent a decrease in wall thickness. To provide.

[0009]

In order to achieve the above-mentioned object, the present invention provides a groove for abutting the outer peripheral surface of a pipe,
A bending die that is rotatably installed; a first clamp that is arranged close to the bending die and that holds the pipe; and a rotating mechanism that rotates the first clamp in the bending direction of the pipe. A second clamp for gripping the pipe during the bending operation of the pipe by the moving mechanism, a push mechanism for pushing the pipe to the first clamp side, and a pipe arranged near the bend die and on the push mechanism side. And a block for preventing buckling.

[0010]

[Operation] Hold the pipe to be bent with the first clamp,
The first clamp is rotated in the bending direction with respect to the rotating bending die via the rotating mechanism. When the tube begins to bend, the tube clamped by the second clamp applies compression to the bend of the tube by a boosting mechanism.

At this time, for 100% of the pulling force of the pipe,
When the pipe is pushed with a slightly strong force of about 102% by the pushing mechanism, the decrease in the wall thickness of the bent portion is eliminated. When the pipe is pushed toward the first clamp side by this pushing mechanism, the pipe is prevented from buckling by the buckling prevention block.

[0012]

Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 is a front view showing an embodiment of a pipe bending apparatus of the present invention, and FIG. 2 is a perspective view of a block in FIG.

This pipe bending apparatus is provided with a rotatable bending die 1 in which a groove for contacting the outer circumference of the pipe 4 is formed. Clamps 3a and 3b are arranged close to the bending die 1. The clamps 3 and 3 are formed with grooves on both sides facing each other so as to contact the outer circumference of the pipe 4, and the clamp 3b can be moved forward and backward in the radial direction of the pipe 4 by the hydraulic cylinder 2.

The gripping mechanism portion provided with the clamps 3a and 3b and the hydraulic cylinder 2 is adapted to be rotated in a direction indicated by an arrow A in the drawing, that is, a bending direction by a rotation mechanism (not shown). In addition, a slide 9 that is in contact with the outer periphery of the tube 4 is arranged parallel to the axial direction of the tube 4. A block 10 is arranged at a position corresponding to the slide 9 and the tube 4, and is connected to a fixing arm 11.

An elongated hole 11a is provided on the upper side of the fixing arm 11.
Is formed, and the block 10 fixed to the fixing arm 11 can be moved back and forth in the axial direction of the pipe 4 by tightening a bolt fixed to the fixing member 12 with a nut,
It can be fixed in place.

Further, a groove that abuts the outer circumference of the pipe 4 is formed, and clamps 13a and 13b for holding the pipe 4 are provided. The clamp 12a can be moved forward and backward in the radial direction of the pipe 4 by a hydraulic cylinder 14.

The gripping mechanism provided with the clamps 13a and 13b and the hydraulic cylinder 14 is a hydraulic cylinder 15a,
It is possible to move back and forth in the axial direction of the pipe 4 by 15b,
As a result, a backward pushing mechanism that pushes the tube 4 in the direction indicated by an arrow B in the drawing while the tube 4 is held by the clamps 13a and 13b is configured.

The block 10 is formed on the bending die 1 as shown in FIG. 2, and is provided with a curved surface portion 10a corresponding to a groove abutting the outer circumference of the tube 4 and a groove portion 10b corresponding to the outer peripheral shape of the tube 4. .. The block 10 is preferably a beryllium alloy having a remarkable age hardening property such as beryllium bronze and excellent in corrosion resistance, heat resistance, wear resistance, fatigue limit and the like.

In the above structure, the pipe 4 is fixed to the bending die 1 by the clamps 3a and 3b by the operation of the hydraulic cylinder 2, and the clamp 13 by the operation of the hydraulic cylinder 14.
The tube 4 is gripped by a and 13b. Then the clamps 3a, 3
When b is rotated in the direction indicated by A in the figure and the pipe 4 begins to bend, the hydraulic cylinders 15a and 15b are interlocked with the bending operation of the pipe 4, and the arrow B in the figure indicates the axial direction of the pipe 4. The pipe 4 is pushed in the direction indicated by, and compression is added to the bent portion of the pipe 4.

The slide 9 and the block 10 are attached to the fixing arm 11 so that the tube 4 will not buckle when the tube 4 is acted upon by the pushing force. The speed (pressurizing force) of the hydraulic cylinders 15a and 15b for pushing can be varied depending on the material and wall thickness of the pipe 4.

In this embodiment, when the clamp 3a, 3b is rotated in the direction indicated by the arrow A in the drawing, the pulling and bending force is 100%, and the hydraulic cylinder 1 for rearward pushing is provided.
The pushing force of the tubes 5a and 15b on the tube 4 is slightly large, for example, 102%.

Under such conditions, when the pipe 4 is bent, it is possible to prevent the wall thickness from being reduced outside the bent portion of the pipe 4. Further, even when the back-pressing force is applied to the tube 4 as described above, the buckling of the tube 4 can be prevented by the slide 9 and the block 10.

[0023]

As described above, according to the present invention, it is possible to bend the pipe with a small bending radius while preventing the buckling of the pipe, and to have a high-quality bent portion in which the ellipticity and the reduction in the wall thickness are reduced. Can manufacture tubes. Therefore, it is not necessary to increase the wall thickness of the pipe to be bent in advance, and the weight of the pipe unit can be reduced.

[Brief description of drawings]

FIG. 1 is a front view showing an embodiment of a pipe bending apparatus of the present invention.

FIG. 2 is a schematic perspective view of a block in FIG.

FIG. 3A is a front view showing an example of a conventional pipe bending apparatus, and FIG. 3B is a schematic configuration diagram showing a usage state of the pipe buckling prevention block in FIG.

[Explanation of symbols]

 1 Bending Dies 2, 14, 15a, 15b, Hydraulic Cylinders 3a, 3b, 13a, 13b Clamps 4 Pipes 9 Slides 10 Blocks

Claims (1)

[Claims] 1. A bending die having a groove formed in contact with an outer peripheral surface of the pipe and rotatably installed, a first clamp arranged near the bending die and gripping the pipe, and a first clamp. 1
Mechanism for rotating the clamp in the bending direction of the pipe, a second clamp for gripping the pipe when the pipe is bent by the rotating mechanism, and the pipe is pushed to the first clamp side. A bending device for a pipe, comprising: a back-pressing mechanism; and a pipe buckling prevention block disposed on the back-pressing mechanism side in the vicinity of the pipe contacting the bending die.