JPH03297517A - Method for bending pipe - Google Patents

Abstract

PURPOSE:To prevent the generation of crack and wrinkle by rotating a bending die from the starting position of bending to the finishing position of bending and making the similarity between the pattern of pressurizing speed of the pressurizing force from the beginning of pipe bending till the finishing of pipe bending and the pattern of rotating speed of the bending die. CONSTITUTION:The pipe P is fastened with the fastening die 2 to the bending die 1 which is freely rotatable and clamped with the wiper 12 and the pressure die 3 adjacent to each other. The bending die is rotated from the beginning position of bending to the finishing position of bending while applying the pressurizing force of the axial direction from the clamping side of pipe toward the fastening side of pipe. The pipe is bent following the rotation of the bending die along the receiving groove of this bending die while forcing the blank material in the bend outer side part of pipe and constricting forcing the blank material with the wiper in the bend inner side part of pipe. Because the similarity between the pattern of pressurizing speed from the beginning of pipe bending till the finishing of pipe bending and the pattern of rotary speed exists, so the difference is not generated between the feeding amt. of pipe with the pressurizing force and the feeding amt. of pipe with the rotation of the bending die.

Description

[Detailed description of the invention] (Industrial application field) The present invention relates to a pipe bending method.

(Prior Art) Many pipe parts that are bent into predetermined shapes are used in automobiles. For example, by using stainless steel pipes for the exhaust manifold, which is an engine part, we aim to improve exhaust efficiency and reduce the weight of the parts without compromising rigidity or durability. .

Regarding the bending method for bending a pipe into a predetermined shape, there are various methods depending on the wall thickness of the pipe, the bending angle, the shape of the pipe parts, etc. An example of one of these methods is shown in Fig. 11. There is a method called the ``draw-bending method.''

In this method, first, a rotatable bending die 1 is used to tighten a pipe P using a die 2, and the back of this pipe P is held down with a pressure die 3.

Under this condition, the bending die 1 is rotated, and as the bending die 1 rotates, the pipe P is drawn and bent into the outer peripheral shape of the bending die 1.

(Problem to be solved by the invention) By the way, the manifold (-, l = - mentioned above) is installed in a narrow engine room where many parts are mounted (=j), so the layout Due to the above constraints, there are cases where it is necessary to perform bending with a small radius of curvature (hereinafter referred to as "minimum bending").
If the outer diameter of the pipe is d, then R≦1. ．． 5d represents the bending process.

When this extremely small bending process is performed using the bending process described above, the material of the pipe P is subjected to tensile force at the outside part of the bend, and compressive force at the inside part of the bend, so that the material of the pipe P is folded and wrinkled at the bend part. etc. may occur, making it impossible to obtain the desired pipe parts. This machining defect state is shown in Fig. 12, and as shown in Fig. 12 (A), the bent outer wall shrinks inward and the hollow hole in the bent part has a flat cross section a, As shown in the same figure (B), there is a crack b on the bent outer wall,
As shown in Figure (C), there are some cases in which wrinkles C are formed on the bent inner wall. Of course, pipe parts with cracks (b) are unfavorable because fluid leaks to the outside, but even if the pipe has a flat cross section (a) or wrinkles (C) have formed, the fluid flowing inside the pipe will not be affected. This is not preferable because it increases the passage resistance.

The present invention has been made in order to solve the problems associated with the conventional techniques, and provides a pipe bending method that can perform extremely small bending of a pipe without causing processing defects. The first goal is to do so.

(Means for Solving the Problems) The present invention for achieving the above object provides a rotatable bending mold in which a receiving groove that contacts the outer periphery of the pipe is formed, and the clamping is performed by tightening the pipe with the mold, and A method for bending a pipe, in which the pipe is bent along the receiving groove of the bending die as the die rotates, the bending die and the tightening member facing the bending die tightening the pipe with the die and the bending die. , a receiving groove connected to the receiving groove of the bending mold is formed, and after the pipe is clamped by a wiper adjacent to the bending mold and a pressure mold facing the wiper, the pipe is tightened from the clamping side to the side. The bending mold is rotated from a bending start position to a bending end position while applying a pressing force in an axial direction toward the pipe, and as the pipe is rotated, the pipe is bent along the receiving groove of the bending mold. A method for bending a pipe, characterized in that the pattern of the pressurizing speed of the pressurizing force and the pattern of the rotational speed of the bending die from the start of bending of the pipe to the end of bending are made similar. be.

(Function) First, the pipe is fastened to a rotatable bending mold by a mold, and is held between a wiper and a pressure mold adjacent to the bending mold.

Thereafter, the bending mold is rotated from the bending start position to the bending end position while applying an axial pressing force to the pipe from the clamping side of the pipe toward the tightening timer side.

Then, the material of the pipe is pushed into the outside part of the bend, and while the pushing of the material is restricted by the wiper in the inside part of the bend, the pipe moves along the receiving groove of the bending die as the bending die rotates. It will be bent.

Moreover, since the pressure speed pattern and rotation speed pattern are similar from the start of pipe bending to the end of bending, there is a difference between the amount of pipe feed due to pressure force and the amount of pipe feed due to rotation of the bending die. There will be no difference.

(Example) Hereinafter, one embodiment of the present invention will be described based on the drawings.

1 to 6 show a pipe bender device embodying the pipe bending method of the present invention.

To summarize, this pipe bender device includes a traveling device 6 that feeds and twists the pipe, a bending mechanism 8 that bends the pipe, and a pressure mechanism that applies axial pressure to the pipe during bending. 10 (A), (
It is used to manufacture pipe parts as shown in B). This pipe component is the above-mentioned exhaust manifold, and is subjected to minimal bending K in order to satisfy layout constraints within the narrow engine room. This pipe bender device continuously bends the pipe in a predetermined direction and angle by numerically controlling the pipe feed, pipe twist, bending angle, etc.

Furthermore, during bending, the bending speed in the bending mechanism 8 and the pushing speed in the pressing mechanism 21 are controlled in synchronization.

More specifically, as shown in FIG. 1.2, the pipe bender device has a bed 4 as the main body of the device, and a rail extending in the direction toward a bending mechanism 8, which will be described later, is provided on the two end surfaces of the bed 4. 5 is provided. On this rail 5,
A table 20 is attached that is movable in the extending direction of the rail 5 and in a direction perpendicular thereto, and a carriage 6 as a traveling device is fixed to the table 20. A chuck 7 is provided at the tip of the carriage 6 to hold one end of the pipe P and to apply twist to the pipe P, so that the chuck 7 is rotatable in both directions about the axis. As the chuck 7 rotates by a predetermined angle, the pipe P also rotates by the predetermined angle to apply the twist.

A twisting motor that rotates the chuck 7 is built into the carriage 6, and a feeding motor that moves the table 20 forward and backward along the rail 5 is built into the table 2.
It is set to 0.

The bending mechanism 8 is provided at the end of the bed 4,
It consists of a clamping part 9 that clamps a predetermined position in the axial direction of the pipe P, and a clamping part 10 that clamps the pipe P and bends it.

As shown in FIG. 4, the holding part 9 is fixed to the bed 4 via a support plate 11, and the wiper 2 is located at the inside bending part of the pipe P and comes into contact with the bending inside wall of the pipe P.
is attached to the support plate 11. This wiper 2
This is to prevent wrinkles from forming on the inner wall of the pipe P during bending.When replacing or installing the pipe, adjust the position and fix it with bolts depending on the outside diameter and bending radius of the pipe P. ing. Vibe P in wiper 2
A receiving groove 12a having a substantially semicircular cross section is formed in the side end face. On the other hand, a first hydraulic cylinder 13 driven by hydraulic pressure is provided on the outer side of the bend of the pipe P of the support plate 11, and a pressure type cylinder 13 facing the wiper 2 is provided at the tip of a rod 14 of this cylinder 13. 3 are connected. Thereby, the pressure mold 3 can move forward and backward with respect to the bent outer wall of the pipe P, and a receiving groove 3a having a substantially semicircular cross section is formed in the end surface of the pressure mold 3 on the pipe P side. After the pipe P held by the carriage 6 is carried in along the receiving groove 12a of the wiper 2, the hydraulic cylinder 13 is driven and the pressure mold 3 moves forward, so that the pipe P is moved in the receiving grooves 12a and 3a. It is designed to hold the

In addition, the tightening part 10, as shown in Fig. 3.5,
It is provided to be rotatable with respect to the bed 4 about a rotation shaft 17, and the rotation shaft 17 has an engagement groove 1 on its upper end surface.
A bending roll 15 on which 5a is formed is connected and fixed. As shown in FIG. 1, on the upper part of this bending roll 15, a cylindrical bending die 1 is provided coaxially with the rotating shaft 17, and a convex portion 1b formed on the lower end surface of the bending die 1 is connected to the engaging groove 15a. It is installed in an engaged state. This bending die 1 is a pipe P
A plurality of bending dies 1 are prepared according to the bending radius of the pipe component, and the bending die 1 is replaced with one suitable for the bending radius of the pipe component.

A receiving groove 1a having a substantially semicircular cross section is formed on the outer peripheral surface of each bending die 1. The wiper 12 described above is attached to the support plate 11 adjacent to the bending die 1 and adjusted to a position where the receiving groove 12a is continuous with the receiving groove 1a of the bending die 1. On the other hand, a bracket 16 attached to the bending roll 15 has a second hydraulic cylinder 1 driven by hydraulic pressure.
8 is provided, and a clamping mold 2 (= J mold 2) opposite to the bending mold 1 is connected to the tip 0 of the rod 19 of this cylinder 18, so that the clamping mold 2 is connected to the outside of the pipe P. It can move forward and backward with respect to the wall.A receiving groove 2a having a substantially semicircular cross section is formed on the end surface of the pipe P side of the J-shape 2. After clamping, the hydraulic cylinder 18 is driven and the mold 2 moves forward to tighten the pipe P in the receiving grooves 1a and 2a. 1
A third hydraulic cylinder 26 is built in as a drive unit for rotating the bending member 0 between the bending start position and the bending end position.
At the tip of the rod 27 of this hydraulic cylinder 26, there is a rack 2 that engages with a pinion 28 provided on the rotation shaft 17.
are connected.

As shown in FIG. 1, the pressurizing mechanism 21 applies an axial pressurizing force from the carriage 6 side to the pipe P held by the carriage 6 and gripped by the clamping part 9. , a chain 2 is placed on the underside of the table 20.
4 is hooked. Further, several electric motors 22 are mounted on the bed 4 to drive the chain 24 via a speed reduction mechanism 23, a clutch, and a guide row 125.

The pressing force is created by driving the chain 24 and pulling the table 20 itself. The value of such pressing force is determined by the bending radius, bending angle, etc. of the pipe component, and is applied to the pipe P from the beginning of bending to the end of bending. An example of the pressing force is as follows.

Pipe outer diameter d pipe wall thickness pipe material Bending radius R bending angle R/d 42.7mm 2. 0mm stainless 0mm 90 degrees 1.4 (minimal bending) in the case of Pressure force 3. 2 tons It is.

By the way, there is a control as shown in FIG. 8 to control the bending speed of the first part 10 and the pushing speed of the pressure mechanism 21 during the bending process. In this case, the pressing mechanism 21 moves forward under constant speed control (speed VO), while the tightening section 10 is accelerated under acceleration/deceleration control in which it accelerates at the start of bending and decelerates at the end of bending. It's rotating.

However, when the above control is adopted, the feed amount and tightening of the pipe due to the pressure applied by the pressure mechanism 21 (=J part), 0
Since there will be a difference between the amount of feed of the pipe due to the rotation of
This may cause problems such as "slippage" and the inability to manufacture high-precision pipe parts.

The inventor of the present invention has determined that in order to prevent the occurrence of "slip" and eliminate the above-mentioned problem, the tightening should be adjusted according to the bending speed of the part 10 and the pressure mechanism 2.
We have developed a method that can be controlled in synchronization with the pressing speed of step 1.

Therefore, in this embodiment, as shown in FIG.
and a bending speed detection means 32 for detecting the bending speed of the tightening section 10 are connected to the control section 30 via the human output section.
The motor 22 of the pressurizing mechanism 21, the third hydraulic cylinder 26 of the tightening part 10, etc. are connected to the pushing speed detecting means 31, which detects the speed using photoelectric pulses. A counter etc. is attached to the table 20 or the carriage 6. Also, as a bending speed detection means 32, an encoder etc.
is attached to.

Then, as shown in FIG. 9, the control section 30 controls the acceleration and deceleration of the motor 22 of the pressing mechanism 21 based on signals from the pushing speed detecting means 31 and the bending speed detecting means 32.

In other words, the pushing speed of the pressing mechanism 21 is set to 1 (1) so that the pattern of the pressing speed of the pressing force and the pattern of the rotational speed of the bending mold 1 are similar from the start of bending of the pipe P to the end of bending. Acceleration/deceleration control is performed in synchronization with acceleration/deceleration control of the hinge section 10. By adopting such synchronous control,
The feeding amount and tightening of the pipe due to the pressure applied by the pressure mechanism 21 are shown in Part 1.
This is done so that there is no difference between the amount of pipe feed due to the rotation of 0 and the amount of feed of the pipe.

Although not shown, a conventionally known mandrel is used when bending the pipe, and the carriage 6
By performing the bending process while being fitted into the pipe P from the side, flattening of the pipe P and generation of wrinkles at the bent portion are prevented.

Next, the operation of this embodiment will be explained.

” To bend the pipe P using a double pipe bender device, select the bending die 1 according to the outer diameter and bending radius of the pipe part, as shown in Figs. It is attached to the bending roll 15''. Further, the wiper 12 is adjusted to a position where its receiving groove 12a is connected to the receiving groove 1a of the bending die 1, and is mounted on the support plate 11.
, the rod 14.19 of the second hydraulic cylinder 13.18 is
Both are in the backward position, and the pressure mold 3 and the tightening mold 2 are retracted with respect to the pipe P.

One end of the pipe P is connected to a chuck 7 at the tip of the carriage 6.
By adjusting and moving the table 20 in the axial direction of the pipe P and in the direction orthogonal thereto, the bending inner wall of the pipe P is aligned with the wiper 12 and the receiving grooves 12a, 1a of the bending mold 1. are in contact with each other.

Under this condition, the table 20 is advanced toward the bending mechanism 8 by a distance corresponding to the portion of the pipe component that is not bent, that is, the straight portion. After that, the first
The hydraulic cylinder 13 is driven to move the pressure mold 3 forward, and the pipe P is held between the wiper 12 and both receiving grooves 12a and 3a of the pressure mold 3, and the second hydraulic cylinder 1 of the tightening part 10
8 to advance the mold 2 and tighten it with the bending mold 1 (=
Tighten the pipe P using both receiving grooves 1a and 2a of the J-shape 2.

Then, by driving the electric motor 22 and pulling the table 20 by the chain 24, the third hydraulic cylinder 26 is driven while applying a preset pressure force to the pipe P. is rotated about the rotation shaft 17 from the bending start position shown in FIG. 3 to the bending end position shown in FIG. At this time, as the bending die 1 rotates, the bending outer wall Po of the pipe 6 P receives a tensile force, but since a predetermined pressing force is applied in the axial direction, both of these forces Since the material of the pipe P is pushed into the bent outer wall Po, cracks will not occur due to thinning of the bent outer wall Po. On the other hand, the portion connected to the bent inner wall is in contact with the receiving groove 12a of the wiper 12, and since the bent inner wall originally receives compressive force due to rotation, an axial pressing force is applied to the bent inner wall. Even if the pressure is applied, the material of the pipe P is not pushed into the bent inner wall, and the pressure is absorbed by the slight increase in the wall thickness of the pipe P that the wiper 12 is in contact with. Therefore, even if the pressurizing force is applied, this force will not be applied to the wiper 12.
Since the curve is regulated by When pipe parts bent under the above-mentioned conditions such as pipe outer diameter, wall thickness, and pressing force were inspected, it was found that the wall thickness of the pipe P in contact with the wiper 12 had increased by only about 20%, and It was also found that since no wrinkles were formed on the inner circumferential surface of the pipe P, it did not increase the passage resistance of the fluid. Furthermore, the inner peripheral surface of the bent portion of the pipe P is flattened by the mandrel fitted inside the vibe P, thereby preventing wrinkles from forming on the inner wall Pi of the pipe P, and flattening the hollow hole of the bent portion. Flattening is being prevented. In this way, while preventing bending defects,
The pipe P is bent around the rotation axis 17 in the receiving groove 1a of the bending die 1.
It will be bent as shown in FIG.

Moreover, as shown in FIG. 9, the pushing speed of the pressurizing mechanism 21 is accelerated/decelerated in synchronization with the acceleration/deceleration control of the section 10, so that the pressure applied by the pressurizing mechanism 21 can be applied to the pipe. There is no difference between the feed amount of the pipe and the tightening (- = pipe feed amount due to the rotation of the J part 10. Therefore, the tightening is done by the part 10.
When tightening, no slippage occurs between the mold 2 and the pipe P, making it possible to manufacture pipe parts with even higher precision.

Then, the rod 19 of the second hydraulic cylinder 18 is moved backward in the state shown in FIG. 10 to the bending start position, one cycle of bending the pipe P is completed.

When proceeding to the next cycle, the table 20 is moved forward according to the straight part of the pipe component, and when bending in a direction different from the bending direction in the previous cycle, the chuck 7
1-2 of the double bending process.
By performing and repeating the cycle, the pipe P is continuously bent in a predetermined direction and angle.

” In this example, R≦1°5d.
It is now possible to perform extremely small bending processes without causing processing defects, and by incorporating the bending process into a numerically controlled pipe bender, highly accurate continuous bending can be performed. It becomes possible to obtain high quality pipe parts, for example exhaust manifolds.

Moreover, since the bending process is performed while controlling the pressure mechanism 21 and the tightening section 10 synchronously, the tightening of the tightening section 10 does not cause "slip" between the mold 2 and the pipe P. It becomes possible to manufacture a single pipe component with even higher precision.

It should be noted that the present invention is not limited to the above-mentioned embodiments,
For example, the pressure mechanism 2 that applies pressure force in the axial direction to the pipe P
1- may be constituted by an actuator driven by hydraulic pressure.

Furthermore, if the pipe P is not to be continuously bent, the traveling device 6 is not required, and in this case, a pressing block is brought into contact with the end of the pipe on the clamping side, and the pressing mechanism 21 is attached to this block. It may be provided.

Furthermore, in the embodiment described above, the control of the pushing speed of the pressurizing mechanism 21 is synchronized with the acceleration/deceleration control of the tightening part 10, but the present invention can control the pushing speed of the pressure mechanism 21 from the start of bending to the end of bending. It suffices if the pattern of the pressure speed of the pressure force up to and the rotation speed pattern of the bending die 1 are similar; It is also theoretically possible to perform constant speed control (see FIG. 8).

(Effects of the Invention) 0 As described above, according to the present invention, since the pipe is bent while applying pressure in the axial direction to the pipe, the outer part of the pipe is thinned. The occurrence of wrinkles can be prevented, and since the pressing force is regulated by the wiper on the inner side of the bend, it is possible to prevent the generation of wrinkles on the inner side of the bend.

Moreover, since the pattern of the pressurizing speed of the pressurizing force from the start of bending to the end of bending and the pattern of the rotating speed of the bending die are made similar, the amount of pipe feed due to the pressurizing force and the rotation of the bending die are There is no longer a difference between the feed rate and the tightening process, and there is no slippage between the mold and the pipe, allowing pipe bending to be performed with even higher precision. obtain.

[Brief explanation of drawings]

FIG. 1 is a side view of a pipe bender device incorporating a bending device embodying the pipe bending method of the present invention, FIG. 2 is a plan view of the pipe bender device, and FIG. 1 is a plan view showing the main parts of the same device before processing, FIG. 4 is a sectional view taken along the line IV-IV in FIG. 3, and FIG. 5 is a sectional view taken along the line ■-■ in FIG. 3. , FIG. 6 is a plan view showing the main parts of the device after bending, FIG. 7 is a schematic block diagram of the control unit that controls the drive of the pressurizing mechanism and the tightening section in the device, and FIG. The figure shows an example of control of the pushing speed and tightening speed of the pressing mechanism (= bending speed of the J-shaped part.
- An example of controlling the bending speed of the pressurizing mechanism and tightening section in the pipe bender device, Fig. 10 (A)
, (B) is a perspective view showing a pipe part bent by the same apparatus, FIG. 11 is a perspective view showing an example of the bending method within the membrane, and FIGS. , is a cross-sectional view showing processing defects that occur during bending. DESCRIPTION OF SYMBOLS 1... Bending die, 3... Pressure die, 9... Holding part, 12... Wiper, 1a... Receiving groove, 2... Tightening die, 4... Bed (equipment) 10... Tightening part, 12a... Receiving groove, 2 26... Third hydraulic cylinder (drive part) 21... Pressure mechanism, P... Pipe.

Claims (1)

[Claims] Pipe bending in which the pipe is tightened by a clamping die against a rotatable bending die in which a receiving groove that contacts the outer circumference of the pipe is formed, and the pipe is bent along the receiving groove of the bending die as the bending die rotates. In the processing method, the pipe is tightened by the bending die and the tightening die facing the bending die, and a receiving groove is formed that is continuous with the receiving groove of the bending die, and a wiper adjacent to the bending die is connected to the pipe. After the pipe is clamped by the pressure mold facing the wiper, the bending mold is moved from the bending start position to the bending end position while applying an axial pressing force to the pipe from the clamping side to the tightening side of the pipe. The pipe is bent along the receiving groove of the bending die with this rotation, and the pattern of the pressurizing speed of the pressurizing force from the start of bending of the pipe to the end of bending is A method for bending a pipe, characterized in that the rotational speed pattern of the bending die is made similar to the pattern.