JPH0147249B2 - - Google Patents

Description

[Detailed Description of the Invention] [Field of Industrial Application] The present invention relates to a bending device applied to, for example, cold bending of pipes, and particularly to a bending device for use in rolling mills, turbines, generators, and other hydraulic piping and pneumatic piping. The present invention relates to a bending device suitable for bending pipes made of a material having elasticity.

[Conventional technology]

Conventionally, cold bending of metal pipes and the like relies on a bender that simply has the ability to bend the pipe to a predetermined bending angle. Since such conventional benders do not have a function to determine whether the amount of bending is excessive or insufficient, the workpiece, such as a pipe, is usually taken out of the bender after bending, and the worker visually measures it. The amount of bending and the amount of wall thickness deviation (the amount of thinning, ie, the amount of pipe wall thickness) are judged to be excessive or insufficient, and then the pipe is mounted on the bender again and corrective bending is performed repeatedly.

[Problem to be solved by the invention]

However, there is no bending device that automatically and continuously corrects the amount of bending, such as the bending angle and amount of wall thickness deviation, at the same time, and as a result, the work is extremely inefficient and takes a long time. Moreover, there were problems in terms of quality, such as the production of products with unstable quality.

The purpose of the present invention was made based on the above circumstances, and has functions for measuring the amount of spring back and corrective bending such as push bending, pulling bending, and free bending, thereby improving work efficiency and product quality. The purpose is to provide a bending device that can be improved.

[Means to solve the problem]

In order to achieve the above object, the present invention has a holding mold that holds a workpiece and a bending mold that removably grips the bending portion of the workpiece at a bending position and applies a bending action. A bending means capable of corrective bending by repeatedly re-holding a bent part of a workpiece, and selectively imparting push-bending, pull-bending, and free-bending functions to the holding mold at the same time while bending the workpiece. a bending means having a means for moving along the axial direction of the workpiece to adjust the amount of uneven thickness of the workpiece; and a bending means arranged at a bending position of the workpiece and operating in conjunction with opening of the workpiece of the bending mold to reduce the spring back of the workpiece. It has a pair of probes that can move forward and backward into the clamping surface of the bending mold against the workpiece, and that are arranged in parallel with a certain interval between them, each contacting the workpiece. A sensor that measures the amount of springback based on the difference in each protrusion amount and the distance between the probes, a memory circuit for a set value of the bending amount for the workpiece, and a memory circuit that stores the set value and the springback amount of the workpiece from the sensor. and a control means having an arithmetic circuit for comparing the bending angle and the amount of bending deficiency in the amount of uneven thickness and a command circuit for giving a correction bending command to the bending means based on the amount of bending deficiency, and controlling the amount of springback. After the measurement, push bending, pull bending, and free bending of the moving means can be automatically and continuously selected.

[Effect]

According to the above configuration, when bending a pipe while measuring the amount of springback with the sensor, the control means not only allows the predetermined bending angle to be reached, but also calculates the amount of uneven thickness of the pipe and bends the pipe axis. Since it is possible to automatically select whether the force along the direction is a pushing force, a pulling force, or a free bending force, it is possible to continuously correct the amount of bending deficiency such as the bending angle and the amount of uneven thickness. Therefore, a pipe with uniform wall thickness and high roundness can be efficiently obtained.

〔Example〕

Hereinafter, one embodiment of the present invention will be described with reference to the drawings. The bending apparatus according to this embodiment is for bending pipes for piping of oil and pneumatic equipment.

First, the bending means will be explained. Bending means 1
As shown in FIG. 1, the pipe has a holding mold 3 that holds the pipe 2, and a bending mold 4 that removably grips the bending portion 2A of the pipe 2 at the bending position and applies a bending action. There is. The holding mold 3 includes a pressure mold 5 that clamps the pipe 2 and a booster clamp mold 6 that are fixed via supports 7 and 8, respectively. The pressure type 5 is adapted to be clamped in a direction perpendicular to the pipe 2 by a pressure type cylinder 9. Further, the booster clamp type 6 is configured to perform a clamping operation in a direction perpendicular to the pipe 2 by a booster clamp type cylinder 11. These booster clamp type 6 and pressure type 5 are connected to the pipe 2 by the booster 10 via the support 8.
It is designed to be able to push, pull, or move freely in the longitudinal direction.

On the other hand, the bending die 4 includes a clamping die 4A that clamps the pipe 2 in a direction perpendicular to the pipe 2 by a cylinder 11A, and a rotating die 1 that can rotate around an axis 12.
3. A gear 14 directly connected to the shaft 12 meshes with a driving gear 15, and a shaft 16 of this gear 15 is directly connected to a hydraulic servo motor 17.

Next, the sensor will be explained. sensor 18
The clamp type 4A is capable of moving forward and backward from the clamp surface, and is spaced at a constant interval l in the pipe axis direction of the clamp surface.
Pin-shaped probes 19, 2 arranged in parallel with
0, as shown in FIG. 3, this is biased in the direction of protrusion from the clamp surface 2A by a drive mechanism 21 using a spring or the like provided inside the clamp mold 4A, and the clamp mold 4A bends and moves. Each of the probes 19 and 20 comes into contact with the pipe 2 when the probe is opened. Then, each probe 1
The difference in the amount of protrusion between 9 and 20 is detected by a detector (not shown) provided within the clamp mold 4A.

Next, the control circuit will be explained. Control circuit 22
has a microcomputer 23 and a sequencer 24 operated by an operation panel 22. The microcomputer 23 includes a memory circuit for storing the set value of the bending amount for the pipe 2, an arithmetic circuit that compares this set value with the springback amount of the pipe 2, and calculates the bending angle and the amount of insufficient bending of the uneven thickness, and a bending circuit. It has a command circuit that gives a correction bending command to the bending means 1 based on the amount of shortage. It also has a control circuit for setting clamping and unclamping of the pipe 2 with respect to the bending means 1, initial bending, etc. And microcomputer 2
3 is connected to a servo motor 17, a sensor 18, etc., and a sequencer 24 is connected to each type of driving cylinder. Note that 25 is a clamp cylinder for fixing the bending mold, and is used when changing the mold, etc.

Next, the operation will be explained. The source of operation is hydraulic. The pressure type cylinder 9, the booster clamp type cylinder 11, and the clamp type cylinder 11A are each operated by a start command from the sequencer 24, and the pressure type 5, the booster clamp type 6, and the clamp type 3 as a holding device are all unclamped.
Thereafter, a pipe 2, which is a material for a bending workpiece, is inserted into the mold. Next, the pressure type cylinder 9, booster clamp type cylinder 11, and clamp type cylinder 11A are operated according to a command from the sequencer 24, and the pressure type 5, booster clamp type 6, and clamp type 3 are clamped with the pipe 2 inserted. In this state, the hydraulic servo motor 17 receives the angle setting signal from the microcomputer 23.
When the rotary die 13 is rotated via the gears 14 and 15, the clamp die 4A is also rotated at the same time.
At this time, the booster 10 is operated in the longitudinal direction of the pipe 2 at the same time as the rotary mold 13, but depending on whether it is a push operation or a pull operation, there are two bending methods: push bending and pull bending. It becomes possible.
In other words, depending on whether the pipe 2 is bent while being pulled or pushed, the bending angle of the pipe 2, the amount of spring back, and the rate of thinning (unbalanced wall thickness of the pipe), etc. are affected.

In this embodiment, it is possible to employ both methods or free bending by not restraining the booster 10, and by selecting these three methods of bending, it is possible to perform bending suitable for various types of pipes. That is,
This bending method is selected by measuring the amount of springback, and then using the microcomputer 23 to calculate the amount of uneven thickness based on the amount of springback. For example, if the uneven thickness exceeds a specified value, the pushing force is selected. If the pipe wall thickness is uniform, free bending is selected, and if the pipe is thick and the thickness is uneven, it automatically and continuously selects pull bending, and this selection is freely controlled. This makes it possible to process pipes with optimal wall thickness. The push bending, pull bending, and free bending can be selected by commands from the microcomputer 23 and whether the booster 10 is pushed, pulled, or free via the sequencer 24. Control of the force is also possible by using a servo valve or the like.

After bending in this way, when only the clamp mold 4A is opened (reversed) by the clamp mold cylinder 11A, the pipe 2 is expanded beyond the normal bending angle due to spring back. Sensor 18 for back amount
The springback amount is detected and calculated by the detection circuit and calculation circuit inside the microcomputer 23, and a corrected bending angle corresponding to the springback amount is calculated and sent to the hydraulic servo motor 17 as an angle signal. give. The hydraulic servo motor 17 further rotates by an angle corresponding to the angle from the normal position. At this time, the open clamp mold 4A is replaced by the clamp mold cylinder 11.
A has returned to the clamped state. Repeat this action several times. Note that if the set angle is obtained by one bending, the work will be completed in one bending. Pipe 2 with normal bending angle
The pressure type cylinder 9, the booster clamp type cylinder 11, and the clamp type cylinder 11A are operated according to instructions from the sequencer 24, and the pressure type 5,
The booster clamp mold 6 and the clamp mold 4A are changed from the clamped state to the unclamped state, and the pipe 2 is taken out. All operation commands for the sequencer 24 and microcomputer 23 are operated by the operation panel 22A. It is also possible to bend pipes 2 with different diameters, but in this case,
The rotary mold 13 may be replaced depending on the pipe diameter.
In this case, the clamp cylinder 11A is clamped to the rotary mold 13 by the clamp cylinder 11A, so the clamp cylinder 11A is unclamped, the rotary mold 13 is replaced, and then the clamp cylinder 11A is changed to the clamped state again to adjust the pipe diameter. It shall be assumed that the

The above operation will be specifically explained with reference to FIG. 4.

In the same figure, A shows the state before bending, B shows the state bent at 90 degrees, and C shows the state where the clamping force of the clamp mold 4A is removed, and the pipe 2 is displaced due to spring back. This spring back amount θ is
As shown in D, a pair of probes 19 and 2 of the sensor 18
0, the spring back amount [θ ₌ ^tan _-1
(δ ₁ − δ ₂ /l)] (where δ
= δ ₁ − δ ₂ ).

Theoretically explaining the bending action based on these functions, as shown in Figure 5, first,
In order to obtain the specified angle θ _A during pipe bending,
When the bending is performed using the initial input value θ and the bending force is removed at point A, the actual bending angle becomes θ ₀ and springback occurs by θ−θ ₀ .

Therefore, in order to get closer to θ _A , if bending force is applied to point B and then removed, the actual bending angle becomes θ ₀
+θ ₁ . Repeat this process several more times to reach a predetermined bending angle _θA .

In this procedure, as shown in FIG. 6, first, bending is started (start 30), and trial bending 32 is performed in accordance with the model input value θ31 of the storage circuit. Next, the insufficient amount θ _o is measured 33 by a sensor, and the main correction θ+θ _o 34 is performed through an arithmetic circuit and a command circuit. After measurement 35 by the sensor, a cross comparison 36 and, if necessary, feedback 37 to measurement of the insufficient amount are performed, and the process is stopped (stop 38) at the end of bending to a predetermined value in accordance with the set value.

According to this embodiment, the pipe can be bent with stable accuracy to a predetermined bending dimension, and quality can be improved. Moreover, this type of action can be performed automatically without the need for removing the pipe from the device.
Can be done continuously.

In addition, in the above embodiment, the bending means can be selected from push bending, pull bending, and free bending, but
Of course, the present invention can also be implemented as a device having only one function.

Furthermore, although the sensor 18 was designed to detect springback by mechanical means, electromagnetic,
Of course, optical means can also be used.

Furthermore, as in the embodiments described above, it is of course applicable to bending not only pipes but also various bar materials.

〔Effect of the invention〕

As explained above, according to the bending apparatus according to the present invention, since the bending process is performed while measuring the amount of spring back when bending the workpiece,
Accurate bending angles can be obtained and bending defects will not occur. Furthermore, since the bending action can be performed automatically and continuously, work efficiency can be significantly improved.

In addition, when bending a pipe as a workpiece, for example, since the pipe has a moving means along the axial direction, it is possible to automatically and continuously select from three methods when bending the pipe: push bending, pull bending, and free bending. By freely controlling this pushing force and pulling force, the pushing force can be used to even out the uneven thickness by pushing the pipe in the axial direction with any force when the uneven thickness becomes large. can,
If you select pulling force, for example, if you want to bend a thick-walled pipe evenly and accurately, if you bend it as is, the wall thickness of the pipe on the bending die side will become extremely thick, so you can apply pulling force. By bending it, you can make a bent pipe with even thickness. In other words, a bent pipe with low wall thickness deviation (uniform wall thickness) can be produced.

The cross section of the pipe can be perfectly circular.

The amount of spring back can be predicted and controlled to the minimum amount, reducing bending time and providing a highly accurate bending angle.

It has excellent effects such as

[Brief explanation of drawings]

The figures show one embodiment of the present invention, in which Fig. 1 is a schematic configuration diagram showing the entire device, Fig. 2 is a configuration diagram showing main parts in detail, and Fig. 3 is a cross-sectional view showing an enlarged sensor section. 4A to 4D are action explanatory diagrams, FIG. 5 is a characteristic diagram explaining the bending theory, and FIG. 6 is a flowchart showing the action. 1... Bending means, 2... Pipe, 3... Holding type, 2A
...bending section, 4...bending mold, 4A...clamping mold,
5...Pressure type, 6...Booster clamp type, 7, 8...
Support, 9...Pressure type cylinder, 10...Booster, 11...Booster clamp type cylinder, 11A
...Cylinder, 12...Axis, 13...Rotary type, 14,1
5... Gear, 16... Axis, 17... Hydraulic servo motor,
18...Sensor, 19, 20...Measure head, 21...Drive mechanism, 22...Operation panel, 23...Microcomputer, 24...Sequencer.

Claims (1)

[Scope of Claims] 1. A holding mold that holds a workpiece, and a bending mold that removably grips the bending portion of the workpiece at a bending position and applies a bending action, and the bending mold holds the bending portion of the workpiece at a bending position. The bending means is capable of corrective bending by repeatedly re-holding the workpiece, and at the same time selectively imparts push-bending, pull-bending, and free-bending functions to the holding die while bending the workpiece, thereby reducing the uneven thickness of the workpiece. a bending means having a means for moving along the axial direction of the workpiece for adjusting the bending means; and a bending means arranged at a bending position of the workpiece and operating in conjunction with the opening of the workpiece of the bending die to detect the amount of springback of the workpiece; , a pair of probes are arranged in parallel with each other with a certain distance between them and are movable toward and away from the clamping surface of the bending mold for the workpiece, each contacting the workpiece, and the difference in the amount of protrusion of each probe. a sensor that measures the amount of springback based on the distance between the measuring probes; a memory circuit that stores a set value of the bending amount for the workpiece; and a memory circuit that stores the set value of the bending amount for the workpiece. and a control means having an arithmetic circuit that calculates an amount of bending deficiency of the amount of uneven thickness and a command circuit that gives a corrective bending command to the bending means based on the amount of bending deficiency, and after measuring the amount of springback, A bending device characterized in that push bending, pull bending, and free bending of a moving means can be automatically and continuously selected.