JPS63101027A - Bending device for square pipe - Google Patents

Abstract

PURPOSE:To enable the bending strenuously restraining the variation in sectional shape by pinching a square pipe by providing a pair of the jigs having the inner face shape corresponding to that of both side faces of the square pipe for working object at the inner side of a pair of jig supporting plates slidable in the axial direction along the outer peripheral face of the roll main body. CONSTITUTION:The jig 9 in the shape and size corresponding to the blank 1 to be worked is provided at the inner side position of each disk 8 in the state of separating a pair of disks 8 by driving a ram 11. The blank 1 is thereafter pinched between jigs 9 by driving the ram 11, disk 8 and jig 9 so as to approach to the blank 1. When the bending is executed by bending rolls 2, 3, 4 in this state, the blank 1 is bent without accompanying the variation in the sectional shape almost because of the remarkable variation of the sectional shape being regulated by the jig 9. And yet for bending of the square pipe in different shapes and sizes the jig 9 may be changed for that in the shape and size corresponding to the square pipe thereof and a quick countermeasure is made possible.

Description

[Detailed description of the invention] [Purpose of the invention] (Industrial application field) The present invention relates to a square tube bending device.

(Prior Art) Bending of plates, tubes, rods, wires, etc. is one of the most widely used forms of secondary forming, and is carried out in many fields. The bending process includes bending of plate materials, wire rods, and steel bars, and bending of pipe materials and shapes. In the latter bending process, the cross-sectional shape accuracy after bending deformation becomes a problem, and this cross-sectional shape accuracy is said to control the processing limit.

In bending a profile, the bending deformation behavior differs between the outer surface and the inner surface of the bend. Therefore, cracking and buckling are likely to occur, and even after bending and deformation, it is difficult to maintain the cross-sectional shape as before deformation. The same applies to circular pipes. That is, as the bending deformation progresses, the cross section becomes flat, buckling occurs on the inside that receives compressive stress, wrinkles occur, and the cross section collapses. One way to prevent the cross-sectional shape from deforming when bending such shapes and pipes is to apply tension to the bending process. Alternatively, there is a method of processing the material in a state where it is filled with an easily meltable alloy, and these methods have been practiced in the past.

Among commonly used bending devices, those using a bending roll device are generally used for bending to a relatively large bending radius. A bending roll device is a processing device that uses three or four rolls, holds a material between these rolls, and bends the material to a certain curvature. There are many ways to arrange the bending rolls. The most common arrangement method is to arrange three rolls as shown in FIG. Processing using this bending roll machine is performed without using a bending die, and by changing the relative position between the rolls, any desired curvature can be obtained.It is widely used as a general-purpose machine for high-mix, low-volume production. has been done.

Next, a case will be described in which a square tube (square vibrator) is bent using this bending roll machine.

When a square pipe is bent using this bending roll machine,
As in the case of bending the profile and inner tube described above, the cross-sectional shape has an allowance. Normally, as shown in FIG. 4, the bend has a trapezoidal cross section in which the width B2 of the inner surface is larger than the width B1 of the outer surface. Additionally, buckling indentations occur on the outside and inside of the bend. In particular, a large dent appears on the inside. The reason for this is as follows. That is, as shown in FIG. 5, on the outer surface of the bend, a tension force acts in the longitudinal direction of the material, and a compressive force acts in the width direction of the material. Further, as shown in FIG. 6, on the bent inner surface, a compressive force acts in the longitudinal direction of the material, and a compressive force acts in the width direction of the material. Due to the compressive force acting in the width direction of the material on both the inner and outer sides of the bend, the end material on both sides of the bend flows into the inner and outer surfaces of the bend. This causes dents on both the inner and outer sides of the bend.

There are various methods for preventing such deformation of the cross-sectional shape. In other words, in the same way as the circular tube described above, there are methods of filling the tube with core metal, sand, or easily melted metal, adding a plate to prevent buckling inside the tube, or increasing the thickness of the material on the inner surface during bending. Several deformation prevention methods have been considered, such as methods to prevent deformation.

However, in bending roll equipment intended for high-mix, low-volume production or general-purpose bending machines, implementing the above measures just to prevent cross-sectional shape deformation when bending the processed material is a major cost increase factor. becomes. Furthermore, the method of filling the pipe with a mandrel or the like cannot be carried out if the square pipe to be bent already has electric wires, wires, insulators, etc. inside it.

(Problems to be Solved by the Invention) As described above, when bending a square pipe, ensuring the cross-sectional size and shape after bending deformation becomes a problem.

Conventional methods used to prevent this are also not effective for high-mix, low-volume production, which is one of the characteristics of the bending roll method. Pre-processing of the material must be minimized as much as possible. There is also a method of inserting a core metal, sand, easily meltable metal, etc. into the pipe, but this results in an increase in the number of additional processing steps after the bending process.

Furthermore, when bending shapes and pipes using a bending roll device, it is necessary to replace the bending rolls according to the material dimensions, and when aiming for a general-purpose machine for high-mix, low-volume production, the time lost in changing rolls is reduced. big.

The present invention has been made in view of the above, and its purpose is to:
It is possible to bend square tubes with minimal changes in the cross-sectional shape without requiring complicated labor during the processing, and it is also possible to quickly bend square tubes of different shapes and dimensions. The object of the present invention is to provide a bending device for square tubes that can be used.

[Structure of the invention]

(Means for Solving the Problems) A bending device of the present invention is a square tube bending device that bends a square tube by sandwiching it between a plurality of bending rolls, in which at least one of the bending rolls is A main body, a pair of opposing jig support plates provided so as to be slidable in the axial direction along the outer peripheral surface of the roll main body, and a jig support plate provided inside each of these jig support plates and used as a processing object. A pair of jigs for clamping the square tube and having an inner surface shape corresponding to the shape of both side surfaces of the square tube.

(Function) Both sides of the square tube to be bent are sandwiched between a pair of jigs whose inner surfaces correspond to the shapes of both sides.

The outside of these jigs is supported by a jig support plate. If an attempt is made to bend the square tube in this state, the bent inner surface of the square tube will tend to expand in the width direction. However, the jig prevents it from spreading. Therefore, free flow of the material of the square tube during bending is inhibited. As a result, the square tube can be bent with almost no change in its cross-sectional shape.

Furthermore, when bending a square tube of a different shape and size from the previous one, the jig may be replaced with one of a different shape and size that corresponds to the new square tube. In this case, there is no need to replace the bending roll itself. Therefore, there is no time lost due to roll replacement.

(Example) Hereinafter, one embodiment of the present invention will be described with reference to the drawings.

In FIGS. 1 and 2, reference numeral 1 indicates a square workpiece material (square tube), and has three bending rolls 2.3.4 for bending the material 1. In FIG. The bending roll 2 has a roll body 7 that rotates together with a rotation axis 6.6. The roll body 7 includes a pair of donut-shaped discs 8 as jig support plates.
8 is fitted along the outer peripheral surface of the roll body 7 so as to be slidable in the axial direction. Thereby, the distance (gap) between the pair of discs 8.8 is configured to be variable.

Inside the pair of disks 8, 8, jigs 9, 9, each having an inner surface shape corresponding to the shape of both side surfaces of the workpiece material 1, are provided so as to be removable. Other jigs used in place of these jigs 9 are also separately prepared. Of course, those other jigs that correspond to the shape and size of the other target material to be processed are selectively used. The above-mentioned jigs 9, 9 are preferably provided so as to be integrally displaced with the pair of discs 8.8. A pair of disks8.
8 is a ram 11.1 provided in the direction of their outer end surfaces.
Driven and supported by 1. those rams 11.11
indicates various driving means (not shown) such as hydraulic equipment and gear equipment
driven by. The drive means thus drive the jig 9.9 in the axial direction via the ram 11.11 and the disc 8.8, adjusting the gap between the jig 9.9, and A workpiece material 1 is held between them.

The device described above is used as follows. That is, first, the ram 11.11 is driven by the drive device so that the pair of disks 8.8 are sufficiently spaced apart. In this state, a jig 9.9 having a shape and size corresponding to the workpiece material 1 to be bent is provided at an inner position of each disc 8.8. Thereafter, the rams 11, 11, disks 8, 8, and jigs 9, 9 are driven to approach each other by the driving device.

The workpiece material 1 is tightly sandwiched in the gap between the jigs 9, which is narrowed by their approach (FIG. 1).

Since the jigs 9, 9 can be moved toward and away from each other in this manner, the gap can be set extremely easily and with high precision. When bending is performed on the workpiece material 1 in this state, the material 1 is bent without any change in cross-sectional shape because the jig 9°9 prevents significant changes in the cross-sectional shape. It will be done. That is, as described above with reference to FIGS. 5 and 6, when the workpiece material 1 is bent, the inner surface 1a tends to expand in the width direction due to the flow of the material, and the outer surface 1a tends to expand in the width direction. The side surface 1b tends to narrow in the width direction. However, the workpiece material 1 is held between the pair of jigs 9.9. Therefore, the free flow of material in the workpiece material 1 is restricted, and deformation of the material 1 is suppressed as much as possible. Therefore, the workpiece material 1 can be bent without substantially changing its cross-sectional shape.

The force that supports the disk 8.8 by the ram 11.11, that is, the force that restrains the deformation of the workpiece material 1, depends on the size, shape, wall thickness, surface roughness, bending radius, etc. of the material 1. and change. This supporting force also varies depending on the size of the gap between the pair of jigs 9 and the size and shape of the jigs.

When the cable material to be bent is changed, i.e.
When the shape and dimensions of the material change, the cross-sectional shape of the material to be processed is changed by replacing a pair of jigs and adjusting the gap between the jigs in the same manner as described above. It can be bent without any bending. In that case, it is natural that there is no need to replace the bending roll itself.

As shown in FIG. 3, the workpiece material 21 is very large.
Even when the disks 28, 28 and jigs 29, 29 protrude outward, if the groove search d of the bending roll 32 is 1/2 or more of the width W of the cable material 21 to be processed, Appropriate bending is possible.

This was confirmed by the inventor's processing experiments under various conditions.

Furthermore, through normal use, the jig inevitably wears out. In this case, it is possible to cope with the wear by replacing the jigs, but it is also possible to cope with the wear by narrowing the gap between the jigs.

In addition, in general, there are quite a few materials to be processed that are very long. In addition, the shape and dimensions may vary somewhat in the longitudinal direction. When bending such a rope material to be processed, it is necessary to measure the shape and dimensions of the material to be processed continuously or intermittently, and to adjust the gap between the jigs. Therefore, in such a case, the shape and dimensions of the workpiece material being bent can be detected by a sensor, and the bending process can be performed while controlling the jig gap in real time.

FIGS. 7 to 9 are diagrams showing the results of experiments conducted to confirm the effects of the apparatus of the present invention.

That is, the experiment was conducted using the apparatus according to the present invention equipped with the bending roll 31 shown in FIG. 10A, and the bending roll 4 shown in FIG.
The experiments were carried out on a conventional apparatus equipped with 1. As is clear from the figure, the bending roll 41 of the conventional device has a roll body 42 and a pair of flange-like disks 43, 43, and a jig 34 like the bending roll 31 of the device of the present invention , 34 does not have. Therefore, a gap 45 is formed between the corner of the workpiece material 1 and the roll body 42 and the disk 43. The material to be processed 1 used was one in which the width of the bent inner surface and the width of the bent outer surface were both B and the height was H8. In FIGS. 7 to 9, data obtained when bending is performed using the apparatus of the present invention is shown by a solid line, and data obtained when bending is performed using a conventional apparatus is shown by a broken line.

FIG. 7 shows the above-mentioned FIG. 10 A, the opening bending roll 31.4.
1 shows the relationship between the gap L in No. 1 and the outer surface width B and inner surface width B2 of the workpiece material after bending. It is clear from this figure that both the lateral and internal bending widths vary significantly when using conventional equipment. On the other hand, it is clear that when the device of the invention is used, the outer and inner widths do not change much, especially the inner width.

FIG. 8 shows the relationship between the above-mentioned gap L and the height H after bending deformation. It is clear that the height H varies considerably in the case of the conventional device, whereas in the case of the device of the invention it does not change much.

Figure 9 shows the above-mentioned gap L and the indentation f on the bent inner surface.
The relationship between f1k and the dent Hk2 on the outer surface is shown. By comparing the amount of denting on the inner surface and the amount of denting on the outer surface by the device of the present invention and the conventional device, the device of the present invention can calculate the amount of denting approximately equal to that of the conventional device. It is clear that it can be reduced to about half.

〔Effect of the invention〕

As described above, according to the apparatus of the present invention, a square tube can be bent while minimizing deformation of its cross-sectional shape, without requiring complicated labor such as pre-processing, post-processing, or inserting a mandrel. Can be done. Furthermore, by exchanging the jig, it is possible to quickly handle bending of square tubes of different shapes and dimensions.

[Brief explanation of the drawing]

FIG. 1 is a sectional view taken along the line I-1 in FIG. 2 showing bending rolls according to an embodiment of the present invention, FIG. 2 is a front view showing the arrangement of the bending rolls, and FIG. FIG. 4 is a perspective view showing a portion of a square tube bent by a conventional device, and FIGS. An explanatory diagram showing the flow direction of the material on the outer surface and the inner surface; FIGS. 7 to 9 are diagrams showing the results of experiments conducted to confirm the effects of the apparatus of the present invention; FIG.
Figure A is a sectional view showing a part of the bending roll used in the above experiment. 1... Wave processed material (square tube), 1a... Inner surface, 1b
...Outer surface, 2.3.4...Bending roll, 6...
Rotating shaft, 7... Roll body, 8... Disc, 9...
Jig, 11...ram. Applicant's agent Sato -Remote Islands I Figure Death 3 Kuchiba 4 Zumura 5 Z Mo 6 Figure! ! lI A0-Aru's key "man 2°L train 9 Figure also 10 Figure 411 C is abused 5 Ze space" = ah Juku C time~:・

Claims (1)

[Claims] In a square tube bending apparatus that bends a square tube by sandwiching it between a plurality of bending rolls, at least one of the bending rolls
A roll body, a pair of opposing jig support plates provided slidably in the axial direction along the outer peripheral surface of the roll body, and a pair of jig support plates provided inside each of the jig support plates. and a pair of jigs that hold the square tube and have an inner surface shape corresponding to the shape of both side surfaces of the square tube to be processed;
A square tube bending device characterized in that it is configured as having: