JP2001239320A - Pipe bender and method of pipe bend using the same - Google Patents

Abstract

PROBLEM TO BE SOLVED: To perform bend very precisely even causing a variety of spring back. SOLUTION: A pipe bender comprises a turnable bending die, a receiving metal case extending tangentially to the outer circumference of the bending die, a clamp fixing a work to the receiving metal case, a pressure die which receive bending reaction force of the work and can retreat so as not to interfere with the work, a correcting clamp which the part of arc in the state of being bent at the designated angle with the bending die and can retreat so as not to interfere with the work, a sensor for detecting the amount of spring back, caused when opening the clamp in the state of being bent at the designated angle, a controlling system deciding the reprocessing amount according to the quantity of spring back, and a driving unit for the bending die, which is controlled by the controlling system.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a pipe bender used for bending pipes and the like.

[0002]

2. Description of the Related Art Bending using a pipe bender is frequently used as one of bending methods for pipe materials. But,
When the workpiece is released from the bending mold after processing, springback occurs and the bending angle varies.Therefore, to perform high-precision bending, check the shape of the bent workpiece using a gauge, etc., and perform correction processing. It is common to do.

In order to solve the above-mentioned problems, Japanese Utility Model Laid-Open Publication No. Hei 4-26622 discloses a sensor for measuring the amount of springback generated when a clamp is released between a workpiece on the outer periphery of a bending die and a sample workpiece. A pipe bender that performs bending and calculates the correction amount of the bending die rotation angle based on the springback amount detection value of the sensor, and bends the work with the corrected bending die rotation angle to obtain high processing accuracy is described. ing.

[0004]

According to the pipe bender described above, bending can be performed with high accuracy. However, even if bending is performed at the same angle on the same lot of material, the amount of springback varies, so that processing is performed. There is a limit to the precision, and correction processing cannot be omitted in order to perform bending processing with higher precision.

[0005] The inventor of the present invention has studied in detail the cause of deterioration in processing accuracy. As a result, when measuring the springback amount, once the clamp is released and the work is clamped again, the bending radius is larger than the curvature radius of the outer periphery of the bending mold due to springback. It has been found that the largest factor of deterioration of bending accuracy is that local bending bends with a radius smaller than the radius of curvature of the outer periphery of the bending die and a gap is formed between the work and the groove bottom of the bending die.

That is, when the bending die is rotated and reworked in a state where a gap is formed between the work and the groove bottom of the bending die,
Since the workpiece is reworked with a smaller radius than the bending die, an angle change larger than the angle at which the bending die is additionally rotated occurs. Since the amount of the gap differs for each work due to the variation of the springback, the angle change of the pipe due to the reworking also differs for each work, and the bending accuracy is limited.

SUMMARY OF THE INVENTION The present invention has been made to solve the above problems, and has as its object to realize a pipe bender capable of performing high-precision bending even if there is variation in springback.

[0008]

SUMMARY OF THE INVENTION A pipe bender according to the present invention is a bending die having a groove which is rotatable and has an outer periphery which matches the shape of a workpiece. A receiving metal provided with a linear groove having the same shape as the groove, a clamp for fixing the work engaging with the metal receiving groove together with the metal receiving, and supporting a bending reaction force from the work when performing bending of the work. A pressure die that can be evacuated to a position where it does not interfere, a straightening clamp that can be evacuated to a position where it does not interfere with the work while clamping the middle of the arc of the work with a bending mold while the work is bent at a predetermined angle, and a state where the work is bent at a predetermined angle A sensor that detects the amount of springback of the work caused by releasing the clamp with the controller, and a controller that determines the amount of rework based on this springback amount , Which is constituted by a drive unit for driving the bending tool under the control of the control means.

In the pipe processing method according to the present invention, the bending end of the work is fixed to the bending mold, the work is bent at a specified angle, and then the work is released from the fixing to the bending mold and the amount of springback generated in the work is released. The pipe is machined by the step of detecting the center position of the workpiece, the step of fixing the middle of the arc portion of the work to the bending mold, the step of fixing the bending end of the work to the bending mold, and performing bending at an angle corresponding to the amount of springback.

[0010] In addition, a single workpiece is bent a plurality of times at an angle corresponding to the amount of springback.

[0011]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Embodiment. FIG. 1 is a detailed view of a main part of a pipe bender according to a first embodiment of the present invention.
This shows a state before bending work in which a workpiece is fixed to a pipe bender. In the figure, reference numeral 10 denotes a work, and 1 denotes a bending die which is rotated about a shaft by a driving device (not shown). A metal holder 2 having the same shape as the groove 1a and provided with a linear groove 2a is attached to the outer peripheral portion of the bending mold 1, and one end of the groove 2a is smoothly connected to the groove 1a. That is, the groove 2a
Extends in the tangential direction of the groove 1a. A sensor 6 is buried in the bottom of the groove 2a, and the amount of springback of the work is obtained from the detection signal and output to the control means 7. Groove 1
A connection position between the groove a and the groove 2a is a bending reference point corresponding to a connection point between the straight portion and the circular arc portion after the work 10 is bent at the bending die reference point. Hereinafter, the state of the bending die 1 shown in FIG. 1 is referred to as a processing start state.

Reference numeral 3 denotes a clamp which can be attached to and detached from the receiver 2, and a groove 3a having a semicircular cross section with which the workpiece 10 is engaged is provided on the surface facing the receiver 2, and the workpiece 3 is clamped by the receiver 2 and the clamp 3. One end of 10 is fixedly held on the bending mold 1. Reference numeral 4 denotes a straightening clamp, which has a groove 4a having the same shape as the clamp 2 and clamps the work 10 in the vicinity of the middle of an arc portion of the work 10 in a state where the work 10 is bent at a predetermined angle. It is arranged to be able to take a clamp position and a standby position which does not interfere with the work 10 when the work 10 is attached and detached. Reference numeral 5 denotes a pressure die for supporting the bending reaction force of the work 10, which is provided with a groove 5a having the same shape as the grooves 1a, 2a and 3a, and the grooves 3a and 5a are aligned on a straight line when the bending die 1 starts processing. And a standby position that does not interfere with the work 10 when the work 10 is attached or detached.

Next, the operation will be described. With the bending die 1 as a processing start state, the pressure die 5 is placed at the standby position, the clamp 3 is opened, and the work 10 is fitted into the groove 1 a so that the bending reference point of the work 10 matches the bending die reference point. The work 10 is supported by fixing the pressure die 5 at the guide position. Thereafter, the bending mold 1 is rotated clockwise by a predetermined angle by a driving device to bend the work 10 along the groove 1a. Here once clamp 3
Is released to cause springback of the work 10.
From the light emitting part of the sensor 6 embedded in the bottom of the groove 2a,
Light is emitted toward the 0 side wall, the incident angle of the reflected light is detected by the light receiving unit, the amount of springback of the work 10 is obtained, and a signal corresponding to the amount of springback is input to the control means 7.

Next, the correction clamp 4 is fixed at the clamp position, and the work 10 is re-clamped by the clamp 3 into the groove 1a. Since the straightening clamp 4 is provided in the middle of the arc portion of the work 10, it can be re-clamped without any gap between the bending die 1 and the work 10. That is, the work 10 reproduces the state before the clamp 3 is released. In order to prevent a gap from occurring between the work 10 and the pressure die 5, it is desirable that the correction clamp 4 be fixed at the clamp position and then re-clamped by the clamp 3. It is desirable that the straightening clamp 4 be an arc having the same radius of curvature as the workpiece 10 after bending, as shown in the figure.

Next, the control means 7 includes a sensor 6
Then, a signal of the reworking amount corresponding to the springback amount of the work 10 detected is output, and the bending die 1 is rotated to finish the working. The workpiece 10 is re-worked after reproducing the same state as before the opening of the clamp 3 by the re-clamping. After the re-working, the same springback amount occurs as when the clamp 3 is opened after the initial bending, so that high bending is performed. Processing accuracy can be realized.

The work hardening of the work 10 and the work 10
The bending angle often slightly exceeds the set value due to a variation in the contact state or frictional force between the metal mold and the bending die 1, the receiving metal 2, the clamp 3, the straightening clamp 4, and the pressure die 5. Therefore, the first rework is performed at about 70 to 80% of the springback amount detected by the sensor 6, and the second rework is performed at about 70 to 80% of the springback amount after this rework. . If necessary, by performing the third reworking at about 70 to 80% of the springback amount after the second reworking, extremely accurate bending can be realized. Practically, it is sufficient to perform the first to third reworkings.

The above description has been made on the assumption that the work is a pipe having a circular cross section. However, the shape of the work is not limited to this example, and a pipe having a rectangular cross section may be used, for example. In this case, as shown in the cross-sectional view of FIG. 2, the groove 1a of the bending die 1 and the groove 2a of the receiving metal 2 have the same cross section as the cross section of the work 10, and the clamp 3, the correction clamp 4, and the pressure die 5 have grooves. It may not be provided. Also, as shown in the cross-sectional view of FIG.
The groove 2a is made deeper than the sectional height of the work 10, and the clamp 3, the correction clamp 4, and the pressure die 5
For example, the projection provided on the workpiece 10 may be fitted to abut the workpiece 10.

Although the case where the sensor 6 is buried in the bottom of the groove 2a has been described, for example, two sensors are installed at positions corresponding to the bending angle of the work 10 on a base (not shown) on which the bending die 1 and the like are mounted. If the amount of springback of the work 10 is detected, the accuracy of detecting the amount of springback can be increased, and more accurate bending can be realized. In addition, although the case where one correction clamp 4 is provided is shown, a plurality of correction clamps 4 may be provided, and this is more effective particularly when the bending angle is large.

Further, the case of the so-called pressing bending in which the relative position between the pressure die 5 and the bending die 1 does not change has been described, but the so-called pull bending in which the pressure die 5 moves together with the work 10 in accordance with the progress of bending of the work 10. It is also possible to apply to cases. In this case, the straightening clamp 4 is configured to be movable in a direction parallel to the moving direction of the pressure die 5, and the clamp position and the standby position are arranged to eliminate the interference between the straightening clamp 4 and the pressure die 5. Factors that hinder the progress of the bending process may be removed by, for example, notching the interference portion between the clamp 4 and the pressure die 5. Of course, one or more straightening clamps 4 may be realized in a small pin shape, for example, to avoid interference with the pressure die 5.

[0020]

The pipe bender according to the present invention is a bending die having a groove which is rotatable and has an outer periphery corresponding to the shape of a workpiece, and a groove extending in a tangential direction of the outer periphery of the bending die and having the same shape as the outer periphery of the bending die. Receiving unit with a linear groove, clamp for fixing the work that engages with the receiving groove together with the receiving unit, and at the position that does not interfere with the work while supporting the bending reaction force from the work when performing the bending process of the work A retractable pressure die, a clamp that clamps the middle of the arc of the work with a bending mold while the work is bent at a predetermined angle, and a correction clamp that can be retracted to a position where it does not interfere with the work, and releases the clamp with the work bent at a predetermined angle A sensor for detecting the amount of springback of the work caused by the operation, control means for obtaining the rework amount based on the amount of springback, Since it is configured with a drive device for driving based on bending-type control, bending can be achieved with high accuracy.

In the pipe processing method according to the present invention, the amount of springback generated in the work by fixing the bent end portion of the work to the bending mold and performing bending at a specified angle, and then releasing the fixing of the work to the bending mold. High accuracy because the pipe is processed by the process of detecting the workpiece, fixing the middle of the arc part of the work to the bending mold, fixing the bending end of the work to the bending mold, and performing bending at an angle equivalent to the amount of springback. Can realize bending.

Further, since the bending of the single workpiece is performed a plurality of times at an angle corresponding to the amount of springback, the bending can be realized with higher accuracy.

[Brief description of the drawings]

FIG. 1 is a schematic diagram showing a configuration of a pipe bender according to the present invention.

FIG. 2 is a partial sectional view showing a first modified example of a clamp portion of the pipe bender shown in FIG.

FIG. 3 is a partial cross-sectional view showing a second modification of the clamp portion of the pipe bender shown in FIG.

[Explanation of symbols]

1 ‥ bending type, 2 ‥ receiver, 3 ‥ clamp, 4 ‥ correction clamp, 6 ‥ sensor 7 ‥ controller, 10 ‥ work

 ──────────────────────────────────────────────────続 き Continuing on the front page (72) Eiichi Sakurai, 2-3-2 Marunouchi, Chiyoda-ku, Tokyo Mitsui Electric Co., Ltd. (72) Taku Shimada 2-2-2, Marunouchi, Chiyoda-ku, Tokyo Mitsubishi Electric Corporation F-term (reference) 4E063 AA04 BC06 CA03 DA04 GA10 JA01 JA07 KA07 LA10

Claims (3)

[Claims] 1. A work in which a work is fixed and held in a groove by a bending die having a groove formed in a periphery thereof and a clamp fixed to an outer peripheral portion of the bending die. In a pipe bender for bending a workpiece, a bending die rotatably provided with a groove on the outer periphery thereof that matches the shape of the work, a straight line extending in the tangential direction of the groove on the outer periphery of the bending die and having the same shape as the groove on the outer periphery of the bending die. A metal receiving groove, a clamp for fixing a work engaged with the metal receiving groove together with the metal receiving, supporting a bending reaction force from the work when performing the bending work of the work, and interfering with the work. A pressure die that can be evacuated to a position that does not interfere with the work, the middle of the arc portion of the work is clamped by the bending mold while the work is bent at a predetermined angle, and the work can be evacuated to a position that does not interfere with the work. A straightening clamp, a sensor for detecting a springback amount of the work caused by opening the clamp in a state where the work is bent at a predetermined angle, control means for obtaining a reworking amount based on the springback amount, and the control means And a driving device for driving the bending die under the control of (1). 2. A step of fixing a bent end portion of a work to a bending mold and performing a bending process at a specified angle, and then releasing the fixing of the work to the bending mold to detect a springback amount generated in the work. A pipe having a step of fixing a middle portion of the arc portion of the work to the bending die and fixing a bent end of the work to the bending die to perform bending at an angle corresponding to the springback amount. Pipe processing method using a bender. 3. A pipe bender using a pipe bender according to claim 2, wherein a step of performing a bending process on the single workpiece at an angle corresponding to the springback amount is performed a plurality of times. Processing method.