JP2001205349A - Bending method for narrow diameter metal tube - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a bending method for a narrow diameter metal tube for bending so as not to generate a clamp flaw on the surface of a narrow diameter metal tube to be worked. SOLUTION: When a working direction of a narrow diameter metal tube to be worked is set and bending is conducted by a bending roll, a tube clamp jig, and a reaction force receiver, after the narrow diameter metal tube to be worked is held by the bending roll and the tube clamp jig, before the reaction force receiver is moved to a working position, the bending roll and the tube clamp jig are turned by a bending angle, the narrow diameter metal tube to be worked is turned/positioned to a reaction force receiving side, next, by moving the reaction force receiver to the working position, the narrow diameter metal tube to be worked is pushed/bent to the bending angle, further, in following the pushing/bending, the clamp jig is turned by a prescribed angle, the narrow diameter metal tube to be worked is bent while pulling.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a technique for bending a small diameter metal pipe.

[0002]

2. Description of the Related Art Conventionally, bending of a small-diameter metal tube has been performed mainly by manual processing using a manually operated jig. However, when bending a small-diameter metal tube manually,
Sufficient processing accuracy cannot be obtained, and processing efficiency is poor. On the other hand, a bending device called a power bender that automatically performs bending of a specific shape and a bending device that is called an NC bender that automatically performs various bending processes are also used. Power benders have relatively low equipment costs and solve the problems of processing accuracy and processing efficiency, but have the drawback that they can only bend a specific shape and are difficult to adapt to shape changes. In addition, the power bender can perform complicated processing on the small-diameter metal pipe in a short time, but has a complicated structure, has a problem in equipment cost, and requires complicated maintenance. Also, a set for changing the processing conditions is complicated and time-consuming.

[0003] On the other hand, the NC bender is an apparatus for performing a bending process set at a plurality of processing positions set in the axial direction of a small-diameter metal tube to be processed, in the processing directions set respectively. Specifically, one end side of the small-diameter metal tube to be processed is chucked, the predetermined small-diameter metal tube is set by rotating the small-diameter metal tube to be processed around an axis, and the small-diameter metal tube is processed. A pipe twisting unit that moves in the axial direction and sets it to a predetermined processing position, and a predetermined angle of rotation while sandwiching the small diameter metal pipe to be processed, and performs bending while pulling the small diameter metal pipe to be processed. A chuck device for gripping one end of a small-diameter metal tube to be processed, and rotating the small-diameter metal tube chucked by the chuck device around an axis. To set a predetermined machining direction, and A pipe twisting unit to be set to a predetermined target processing position by moving the Engineering thin metal tube in the axial direction,
While pressing the bendable roll and the small-diameter metal pipe to be processed against the peripheral surface of the bend roll, the work piece is rotated by a predetermined angle on the peripheral surface through the small-diameter metal pipe to be processed, and It is provided with a clamp jig for sequentially pulling and bending the one end chucked from the front end side of the other end, and a bending device having a reaction force receiving of a small-diameter metal tube to be processed at the time of bending.

FIG. 2 illustrates an example of a bending method by an NC bender that performs bending while pulling a pipe.
The bending device 11 rotates the bending roll 11-1 and the peripheral surface of the bending roll by a predetermined angle on the peripheral surface through the processing narrow-diameter metal tube while pressing the processing-purpose small-diameter metal tube P against the peripheral surface. A bending jig 11-1 is provided with a narrow clamping jig 11-2 for bending and bending, and a pressure die (reaction force receiving) 11-4.
1 and the clamp jig 11-2 are integrally attached to the bend arm 11-3.

[0005] That is, in the conventional bending process, a small diameter metal pipe P to be processed is clamped by a bending roll 11-1 and a clamp jig 11-2, and then a pressure die (reaction force receiving) 11-.
4 is moved forward to make contact with the small-diameter metal pipe P to be processed, and in this state, the bending is performed by rotating the bend arm 11-3 by a predetermined angle. At the time of this bending, the metal pipe P to be processed is bent while being pressed against the peripheral surface of the bending roll 11-1 while being pulled by the clamp jig 11-2.

[0006]

However, in the above-described conventional bending method, one operation is performed while pulling the small-diameter metal pipe P to be processed while being clamped by the bending roll 11-1 and the clamp jig 11-2. In order to perform the prescribed bending process with
The small diameter metal pipe P to be processed must be strongly clamped,
At the time of the bending, as shown in FIG. 3, a large clamping force as shown by an arrow is applied to the small-diameter metal pipe P to be processed, and local buckling occurs on the surface of the small-diameter metal pipe P to be clamped. There is a problem that a concave bite flaw called a mark is formed.
Also, as shown in the figure, when the bending stop position in the previous process and the bending start position in the next process are close, the small-diameter metal pipe P to be processed is used.
In order to cope with this, a groove 21 conforming to the bending shape of the previous process is provided on the bending roll 21-1 and the clamp jig 21-2 as shown in FIG.
-3 is required to be used as the total die 21, which not only increases the cost of the die but also cannot be used for linear bending only with this bending-only die. Therefore, as shown in FIG. ′, And a two-stage bending unit provided with a bending roll 21-1 ′ and a clamp jig 21-2 ′.

The present invention has been made in order to solve such a problem, and it is possible to perform a bending process using an NC bender similar to the conventional one so that a concave clamp mark is not formed on the surface of a small-diameter metal tube to be processed. Another object of the present invention is to propose a method of bending a small-diameter metal pipe, which does not require a complete mold or a two-stage bending unit.

[0008]

In order to solve the above-mentioned problems, a method for bending a small-diameter metal tube according to the present invention comprises the steps of: rotating a bending roll and a clamp jig to an intermediate bending position; A method of pressing and bending a small-diameter metal tube to be processed by a die (reaction force receiving), and a method of applying a tensile bending process after the pressing and bending. The machining direction is set by rotating the shaft by a predetermined angle about its axis, and the thin metal tube to be machined is clamped by a bending roll and a pipe clamp jig, and the reaction force receiver is moved to the machining position for machining. In a state of contact with the small-diameter metal pipe, the bending roll and the clamp jig are rotated by a predetermined angle while pressing the small-diameter metal pipe to be processed against the peripheral surface of the bending roll, and the small-diameter workpiece is processed. A bending method that bends a metal tube while bending it. After holding the small-diameter metal pipe to be processed between the bending roll and the pipe clamp jig, the rear end of the pipe is opened, and the bending roll and the pipe clamp jig are bent before the reaction force receiver is moved to the processing position. Rotating the angle to move the small-diameter metal tube to be processed to the reaction force receiving side, and then moving the reaction force receiver to the processing position to press and bend the small-diameter metal tube to be processed at the bending angle, Further, the second embodiment is characterized in that, following the above-mentioned press-bending process, the bending process is performed while rotating the clamp jig by a predetermined angle to pull the small-diameter metal tube to be processed.

[0009]

DESCRIPTION OF THE PREFERRED EMBODIMENTS FIG. 1 is a schematic perspective view showing one embodiment of a method for bending a small diameter metal pipe according to the present invention.

That is, in the bending of the small-diameter metal tube P according to the present invention, when the small-diameter metal tube P is bent by the bending device 1 as shown in FIG. After clamping with 1-1 and clamp jig 1-2, the rear end of the pipe is opened and pressure die (reaction force receiving) 1
-4 is a position distant from the small-diameter metal pipe P to be processed, and the bend arm 1-3 is rotated by an angle θ to a halfway bending position so that the unprocessed side of the small-diameter metal pipe P to be processed is a pressure die (reaction force). Receiving) 1-4 side, and in this state, the pressure die (reaction force receiving) 1-4 is moved forward to the processing position, and the thin metal pipe P to be processed is pressed against the arc groove of the bending roll 1-1. While performing the first bending process at the bending angle θ. This first
Since the bending of the step is a press bending by a pressure die (reaction force receiving) 1-4, the clamping force applied to the small-diameter metal pipe P to be processed may be relatively small, and a large force may be applied to the pre-process side corner of the chuck. There is no concentration of power. Therefore, at the time of this bending, the surface of the small-diameter metal pipe P to be processed hardly has a biting flaw called a concave clamp mark due to buckling.

When the first-stage press bending is completed,
In order to perform the second-stage (final bending) bending, the bend arm 1-3 is rotated by the remaining angle while the pressure die (reaction force receiving) 1-4 is fixed at the first-stage bending position. Perform the final bending process. In this bending process, the small-diameter metal pipe P to be processed is bent while being pressed by the arc groove of the bending roll 1-1 while being pulled by the clamp jig 1-2.
At this time, since the small-diameter metal tube P to be processed is partially bent by the first-stage press bending process, even if the remaining bending is performed by the tension bending process, the small-diameter metal tube P to be processed remains in the bending roll 1.
It is not necessary to strongly clamp the small-diameter metal pipe P to be processed because it receives a frictional force while being fitted into the -1 arc groove. Therefore, a large clamping force is not applied to the small-diameter metal pipe P to be processed even in the second-stage tension bending process, so that the surface of the small-diameter metal pipe P to be processed has a cut-in flaw called a clamp mark. Few things. If the bending angle is small, subsequent bending may not be necessary.

[0012]

As described above, the present invention is a method of bending a small-diameter metal tube with a pressure die (reaction force receiving) while rotating a bending roll and a clamp jig to an intermediate bending position. In addition, since the bending is performed by tension bending following the pressing and bending, a large clamping force is not applied to the small-diameter metal pipe during the pressing and bending, and therefore, a concave clamp mark is formed on the surface. An excellent effect of obtaining a high-quality bent product having almost no bite flaws and the like, which is referred to as a bite defect, can be obtained. Further, since the present invention does not require a complete mold or a two-stage bending unit, the equipment cost does not increase.

[Brief description of the drawings]

FIG. 1 is a schematic perspective view showing one embodiment of a method for bending a small diameter metal tube according to the present invention.

FIG. 2 is a schematic perspective view showing an example of a conventional method for bending a small diameter metal tube to which the present invention is applied.

FIG. 3 is a schematic perspective view showing an enlarged main part of the conventional bending method shown in FIG. 2;

FIG. 4 is a schematic perspective view showing another example of a conventional method for bending a small diameter metal tube.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Bending apparatus 1-1 Bending roll 1-2 Clamp jig 1-3 Bend arm 1-4 Pressure die (reaction force receiving) P Worked thin metal pipe

Claims (2)

[Claims] 1. A small-diameter metal tube to be processed is rotated by a predetermined angle about its axis to set a processing direction, and the small-diameter metal tube to be processed is clamped by a bending roll and a pipe clamp jig. And, in a state where the reaction force receiver is moved to the processing position and abutted against the small-diameter metal pipe to be processed, the bending roll and the clamp jig are pressed while pressing the small-diameter metal pipe to be processed against the peripheral surface of the bending roll. In the bending method in which the tool is rotated by a predetermined angle to bend while pulling the thin metal pipe to be processed, the thin metal pipe to be processed is clamped between a bending roll and a pipe clamp jig, and then a rear end of the pipe is formed. Before moving the reaction force receiver to the processing position, the bending roll and the pipe clamp jig are rotated by a bending angle to move the small-diameter metal tube to be rotated to the reaction force receiving side, and then the reaction force Move the holder to the processing position to bend the small-diameter metal A method for bending a small-diameter metal tube, characterized by press bending. 2. A processing direction is set by rotating a small-diameter metal tube to be processed by a predetermined angle around its axis, and the small-diameter metal tube to be processed is clamped between a bending roll and a pipe clamp jig. And, in a state where the reaction force receiver is moved to the processing position and abutted against the processing thin metal pipe, the bending roll and the clamp jig are pressed while pressing the processing thin metal pipe against the peripheral surface of the bending roll. Is rotated by a predetermined angle to bend while bending the small-diameter metal pipe to be processed.In the bending method, the small-diameter metal pipe to be processed is clamped by a bending roll and a pipe clamp jig, and then the rear end of the pipe is clamped. Before the reaction force receiver is moved to the processing position, the bending roll and the pipe clamp jig are rotated by a bending angle to move the small-diameter metal tube to be rotated to the reaction force receiving side. To the processing position and press the metal pipe to be processed to the bending angle. And bending the clamped jig, and then bending the clamped jig by a predetermined angle to apply tension to the small-diameter metal pipe to be processed.