JPH0446633A - Method and device for bending tube - Google Patents

Abstract

PURPOSE:To miniaturize the tube bending device and to serve the space-saving by arranging the bending rollers at the position matching to the bending shape of tube to be bent and passing the tube into its bending roller line. CONSTITUTION:The tube 11 is pulled out from the un-coiler 12 by rotating the pulling rollers 28, 29, elongated straightly on the process passing the leveling rollers 14-17, and the pulled quantity of the tube 11 is measured by rotating the measuring roller 18. And then, the tube 11 is passed in the guiding member 37, guided straightly to the bending roller line of the right side. When it is brought into contact with the bending roller 25, the top of its tube 11 is bent so as to face toward the inner side, after then by passing the tube 11 between the bending roller of the outer circumferential side and the vending roller 24 of the inner circumferential side, the tube 11 is bent.

Description

[Detailed Description of the Invention] [Object of the Invention] (Industrial Application Field) The present invention relates to a pipe bending method for bending a cold-plastically workable pipe made of iron, copper, aluminum, etc. into a predetermined shape. method and equipment for the same.

(Prior Art) Conventionally, a device for bending heat dissipation pipes and dew prevention pipes used in refrigerators, for example, is shown in FIGS. 10(a) to 10(d).
The pipe 1 is bent using the following steps. That is, according to the conventional pipe bending device 4, as shown in FIG.
First, each set of positioning rollers 2 and bending rollers 3 are arranged horizontally in a straight line with a straight pipe 1 cut into a predetermined length.
be sandwiched between. Next, as shown in FIG. 2B, for example, the bending rollers 3 at both ends are rotated by 180e in the direction of arrow A around the positioning roller 2, thereby bending both ends of the pipe 1 inward.

After that, as shown in FIG.
A second bending process is performed by rotating it by 80 degrees. Finally, as shown in the same figure (d), move the central bending roller 3 around the positioning roller 2 in the direction of arrow
All bending steps are completed by rotation.

(Problems to be Solved by the Invention) When bending, for example, a heat dissipation pipe for a refrigerator using the conventional pipe bending device 4, the area occupied by the pipe bending device 4 is the entire length of the straight pipe before bending. The size is about the same as the length of 1 (for example, 11 to 12 m), and the width W is also
Considering the turning radius of pipe 1 during bending, for example, 3
It requires a size of ~4m. For this reason, the area occupied by the pipe bending device 4 becomes extremely large, and as a result, the number of pipe bending devices 4 that can be installed in one factory (limited work space) decreases. The overall production capacity is low, and if the pipe bending device 4 occupies a large area, the factory site to accommodate it must also be expanded, which increases equipment costs. .

The present invention has been made in consideration of such circumstances, and its purpose is to provide a pipe bending method and apparatus that can improve production capacity by saving space and reduce equipment costs.

[Structure of the Invention (Means for Solving the Problems)] The pipe bending method of the present invention comprises arranging a plurality of bending rollers along both the inner and outer circumferences of a bending curve that matches the bending shape of the pipe. The pipe is bent into the same shape as the bending curve by forming a row of bending rollers and passing the pipe through the bending roller row along the bending curve.

In order to carry out the invention of the pipe bending method, the pipe bending device of the present invention includes a plurality of bending rollers arranged along both the inner and outer circumferences of a bending curve that matches the bending shape of the pipe. a pipe feeding device that feeds the pipe through the bending roller row so as to pass the pipe along the bending curve to form a bend, and after the pipe is bent, between an inner bending roller and an outer bending roller. It consists of a roller opening device that widens the interval between the curved pipes and allows the bent pipe to be taken out.

In this case, the support bed is divided into a support bed that supports the plurality of bending rollers on the inner circumference side and a support bed that supports the plurality of bending rollers on the outer circumference side. The bending roller may be slid integrally with the support bed to widen the distance between the inner bending roller and the outer bending roller.

Furthermore, rows of bending rollers are provided at positions corresponding to each bending portion of the pipe so that the pipe can be bent into a meandering shape, and bending rollers on both sides in the meandering width direction are provided so as to adjust the meandering width of the pipe. A configuration may also be provided in which a meandering width adjustment device is provided to adjust the spacing between columns.

In this case, a guide member for guiding the pipe is provided between the bending roller rows located on both sides of the pipe in the meandering width direction, and the length of this guide member is configured to be adjustable according to the interval adjustment between the bending roller rows. It's okay.

(Function) According to the pipe bending method of the present invention, the bending rollers are arranged in advance at positions matching the bending shape of the pipe, and the pipe is sequentially bent by passing the pipe through the bending roller row. Therefore, the size of the pipe bending device can be reduced to approximately the same size as the bent pipe (finished product).

Further, according to the pipe bending device of the present invention, after bending the pipe, when taking out the bent pipe sandwiched between the bending roller rows, the roller release device is used to remove the inner bending roller and the outer circumference side bending roller. You can widen the distance between. As a result, the bent pipe is no longer held between the bending roller rows, and the bent pipe can be easily taken out from the bending roller rows.

In this case, a support bed that supports the plurality of bending rollers on the inner circumference side and a support bed that supports the plurality of bending rollers on the outer circumference side are divided, and at least one of the support beds is slid by a roller release device. Then, as the support bed slides, a plurality of bending rollers can be slid inside the support bed to widen the gap between the inner bending roller and the outer bending roller, and the rollers are released. The configuration of the device is significantly simplified.

Furthermore, rows of bending rollers are provided at positions corresponding to each bending portion of the pipe so that the pipe can be bent into a meandering shape, and bending rollers on both sides in the meandering width direction are provided so as to adjust the meandering width of the pipe. If the spacing between the rows can be adjusted by the meandering width adjusting device, meandering pipes with different meandering widths can be manufactured using one pipe bending device, and the device can be used for general purposes.

In this case, if a guide member for guiding the pipe is provided between the bending roller rows located on both sides of the pipe in the meandering width direction, and the length of this guide member is adjustable, the interval between the bending roller rows can be adjusted. In some cases, the length of the guide member can be adjusted to the optimum length depending on the amount of adjustment, so the pipe guiding action by the guide member between the rows of bending rollers is ensured, and the tip of the pipe is securely aligned with the bending rollers. You will be able to pass through the line.

(Example) Hereinafter, a first example of the present invention will be described based on FIGS. 1 to 6.

The pipe 11 used in this embodiment is a cold-plastically workable pipe made of, for example, iron, copper, aluminum, etc., and is wound around an uncoiler 12. In order to straighten the pipe 11 pulled out from the uncoiler 12, a leveler 13 is provided in the direction in which the pipe 11 is pulled out. This leveler 13 is composed of two pairs of leveling rollers 14 to 17, of which one pair of leveling rollers 14 and 15 are arranged on both sides of the pipe 11 in the horizontal direction so as to correct the bend in the horizontal direction of the pipe 11. The remaining pair of leveling rollers 16 and 17 are arranged on both sides of the pipe 11 in the vertical direction so as to correct the bending in the vertical direction.

A measuring roller 18 is provided ahead of the leveler 13 (on the right side in the figure) so as to sandwich the pipe 11 between it and a pressure roller 19 in order to measure the feed amount of the pipe 11. It is designed to rotate in synchronization with the feed of 11.

A rotary encoder (
A pulse signal synchronized with the rotation of the measuring roller 18 is sent from this rotary encoder to an operation control device (not shown), and by counting this pulse signal, the amount of feed of the pipe 11 is determined. It is now being measured.

A cutter 20 is provided ahead of the measuring roller 18, and the cutter 20 operates to cut the pipe 11 when the pipe 11 is fed out a predetermined length through the cutter 2o (at the end of bending).

On the other hand, in front of this cutter 20, two sets of support beds 22.23 of the pipe bending device 21 are provided in parallel to each other, facing left and right.
．． 25 are arranged.

In this embodiment, in order to manufacture a heat dissipation pipe for a refrigerator by bending the pipe 11 into a meandering shape, a plurality of Bending rollers 24 and 25 are arranged, and bending roller row 2
6 are configured.

Then, every other bending roller 25 on the outer peripheral side is connected and driven by a chain 30 (see FIG. 3) or the like, so that it also functions as a pipe feeding device for feeding the pipe 11. In this case, the feeding speed of the pipe 11 is, for example, 1
~2m/sec. As shown in FIG. 4, each bending roller 24, 25 is formed with a groove 248.25a having the same curvature as the outer diameter of the pipe 11.
The pipe 11 is fitted into the pipe 11 so that it is bent while being prevented from slipping off. As shown in FIG. 1, pull-out rollers 28 and 29 for pulling out the pipe 11 straight are provided at positions corresponding to both ends of the curved pipe 11 (heat dissipation pipe) so as to sandwich the pipe 11. ing. The pull-out rollers 28, 29 are driven to rotate in synchronization with the bending roller 25 by a chain drive mechanism (not shown) or the like, and the pull-out rollers 28, 29 and the bending roller 25 are connected to a pipe feeding device. It consists of

On the other hand, each set of support beds 22, 23 is divided into two support beds 22a+22b and 23a, 23b along the passage path of the pipe 11, as shown in FIG. 23a supports the bending roller 27 and the pull-out roller 29 on the outer circumference side, and the other support beds 22b and 23b support the bending roller 26 and the pull-out roller 28 on the inner circumference side. And each support bed 2
2a, 22b and 23a, 23b are supported so as to be slidable in the left-right direction, and are moved from the closed position shown in FIG. 1 to the open position shown in FIG. 2 in opposite directions by, for example, a cylinder device 31 (see FIG. 3). The bending roller 2 on the inner circumferential side is
4 and the bending roller 25 on the outer peripheral side is widened, so that the bent pipe 11 can be easily taken out. Therefore, in this embodiment, the support bed 22a is divided into two parts.

22b, 23B, 23b and the cylinder device 31 constitute a roller opening device.

Furthermore, in this embodiment, the right support bed 23 is equipped with a meandering width adjustment device 3 so that the meandering width g of the pipe 11 can be adjusted.
2 (see Fig. 3) allows it to slide in the left and right direction. This meandering width adjustment device 32 has a threaded rod 34 rotated by a motor 33 horizontally in the left-right direction, and a threaded hole 36 formed in a support leg 35 that supports the support head 23 is inserted into the threaded rod 34. It is constructed by screwing together. As a result, if the motor 33 is rotated in the forward direction, the support bed 2
3 slides to the left, and if you rotate it in the opposite direction, it will slide to the right.

On the other hand, between the bending roller rows 26 (between the support beds 22 and 23) located on both sides of the pipe 11 in the meandering width direction,
1 or a plurality of unit guide members 37
It is divided into sections a and arranged in a line. As shown in FIG. 5, each unit guide member 37a includes a pair of L-shaped members 39a, 39 whose receivers are slidably provided on a plate 38.
b, and during the bending process, the gap between the double-sided members 39a and 39b is narrowed to slightly larger than the outer diameter of the pipe 11 using a cylinder device (not shown) or the like.
is guided straight to the bending roller row 26, while after the bending process is completed, the interval between the double-sided members 39a and 39b is
It is expanded as shown by the two-dot chain line in the figure to make it easier to take out the pipe 11. In addition, in order to make the length of all the guide members 37 adjustable in accordance with the interval adjustment between the left and right bending roller rows 26, as shown in FIG. The several unit guide members 37a located are
The supports are supported by the rods of cylinder devices 40, respectively, and as the distance between the left and right bending roller rows 26 is narrowed, the cylinder devices 40 are operated in order from the right side to lower the unit guide members 37a in order, thereby lowering the guide members. This is to adjust the entire length of 37.

Next, the operation of the above configuration will be explained. When manufacturing a heat dissipation pipe by bending the pipe 11, first, the pipe 11 pulled out from the uncoiler 12 is passed through the leveler 13.
It is set so that it is passed through the leveling rollers 14 to 17 and then between the measuring roller 18 and the pressing roller 19. Then, every other two pull-out rollers 28 and the outer bending roller 25, which are pipe feeding devices, are driven to rotate.
Start bending. At this time, the pull-out rollers 28, 2
9, the pipe 11 is pulled out from the uncoiler 12 at a speed of, for example, 1 to 2 m/sec, and the pulled out pipe 11 is stretched straight in the process of passing through leveling rollers 14 to 17, and the rotation of the measuring roller 18 The amount by which the pipe 11 is pulled out is measured. The pipe 11 sent out from the pull-out rollers 28 and 29 is
First, as shown in FIG. 6(a), it is passed through the guide member 37 and guided straight to the bending roller row 26 on the right side. As a result, the tip of the pipe 11 is bent by the bending roller row 26.
When the pipe 11 reaches the inlet and contacts the bending roller 25 that is being driven on the outer circumference side, the tip of the pipe 11 is bent inward by the bending roller 25, and then the bending roller 25 on the outer circumference side is bent in turn. 25 and the inner bending roller 24
By passing the pipe 11 between the
is curved as shown in FIG. 6(b). In the bending roller row 26, the bending roller 25 on the outer peripheral side is one
By being driven every other bending roller 25, the bending roller 25 also functions as a pipe feeding device, whereby the tip of the pipe 11 is sent out from the bending roller row 26, and as shown in FIG. It passes through the guide member 37 of. Thereafter, when the above-mentioned operation is performed for all the bending roller rows 26, the pipe 11 is bent into a meandering shape, so that the tip of the pipe 11 is bent by the exit rollers 28, 29 as shown in FIG. When the pipe 11 is fed out, the measured value of the amount of the pipe 11 pulled out by the measuring roller 18 becomes a predetermined value, the rotation of the drawing rollers 28 and 29 and the bending roller 25 is stopped, and the feeding operation of the pipe 11 is stopped. After stopping, the cutter 20 is operated to cut the pipe 11.

After this, when taking out the meandering pipe 11 (finished heat dissipation pipe) from the bending rollers 24, 25, the support beds 22a, 22b and 23a, 23b are moved by the cylinder device 31 as shown in FIG. The bending rollers 24, 25 are opened by sliding them in opposite directions from the closed position shown in FIG. 2 to the open position shown in FIG. At the same time, the distance between the L-shaped members 39a and 39b of the guide member 37 is widened as shown by the two-dot chain line in FIG. 5 to make it easier to take out the pipe 11. In this state, the pipe 11 is received on the plate 38, and the pipe 11 can then be taken out upwardly from there by an appropriate means.

On the other hand, when adjusting the meandering width p of the pipe 11, an appropriate cylinder device 40 is operated according to the amount of adjustment of the meandering width g, an appropriate number of unit guide members 37a are lowered, and the guide member 37 Adjust the overall length. Then,
The motor 33 is operated to rotate the threaded rod 34, thereby sliding the right support bed 23 and adjusting the interval between the left and right bending roller rows 26. Thereafter, by performing the steps described above, bent pipes 11 (heat dissipation pipes) having different meandering widths p can be manufactured.

According to the pipe bending method of the above embodiment, the pipe 11 is
Since the pipe 11 is bent by arranging the bending rollers 24 and 25 at positions corresponding to the bending shape and passing the pipe 11 through the bending roller row 26, the size of the pipe bending device 21 is The size can be reduced to almost the same size as the bent pipe 11 (finished product). As a result, the total length of the pipe bending device 21 has been reduced from the conventional 11 to 12 m to 3 m.
Significantly smaller at around 3.0 ft (m), and the width is also 3 to 4 m compared to the previous model.
As a result, the area occupied by the pipe bending device 21 is reduced to about 1/10 of that of the conventional pipe bending device 21, making it possible to save a large amount of space. As a result, the number of pipe bending devices 21 that can be installed in one factory (limited work space) can be significantly increased compared to conventional methods, dramatically increasing the production capacity of the factory as a whole. Moreover, if the area occupied by the pipe bending device 21 is reduced, the factory site (work space) for accommodating it will also be small, and the equipment cost can be reduced accordingly.

Furthermore, according to the pipe bending device 21 having the above configuration, after bending the pipe 11, the support beds 22a, 22b and 23a, 2
3b is slid by the cylinder device 31 from the closed position shown in FIG. 1 to the open position shown in FIG. 2 to open the bending rollers 24 and 25. 26 is released, and the bent pipe 11 is bent by the roller row 2.
It can be easily taken out from 6.

Moreover, the support beds 22b and 23b that support the plurality of bending rollers 24 on the inner circumference side and the plurality of bending rollers 2 on the outer circumference side are provided.
A support bed 22a that supports 5.

23a, and at least one of the support beds is slid by the cylinder device 31, so that as the support bed slides, a plurality of bending rollers 24 and 25 are slid integrally with the support bed. The distance between the bending roller 24 on the circumferential side and the bending roller 25 on the outer circumferential side can be increased, and the configuration for opening the bending rollers 24 and 25 can be significantly simplified, contributing to cost reduction.

Furthermore, bending roller rows 26 on both sides of the pipe 11 in the meandering width direction
Since the configuration is such that the interval between the meandering widths can be adjusted by the meandering width adjusting device 32, meandering pipes 11 with different meandering widths p can be manufactured by one pipe bending device 21, and the pipe bending device 21 It has the advantage of being generalizable.

In this case, a guide member 37 disposed between the bending roller rows 26
Since the length of the bending roller row 2 is adjustable,
The length of the guide member 37 can be adjusted to the optimum length according to the adjustment of the interval between the bending rollers 26, and the guiding action of the pipe 11 by the guide member 37 between the bending roller rows 26 is ensured. The leading end is reliably passed through the bending roller row 26, and the rate of defects can be reduced.

In the above embodiment, in order to open the bending rollers 24 and 25, the support beds 22 and 23 are divided into two parts, and at least one of the support beds is slid by the cylinder device 31, thereby opening the plurality of bending rollers 24 and 25. However, as in the second embodiment of the present invention shown in FIG. 7, a link 43 is connected to the bearing 24a of each bending roller 24 via a spring 42, respectively. The roller opening device 46 may be configured by connecting each link 43 with one pin 44 and connecting it to the rod of one cylinder device 45. in this case,
When bending the pipe 11, the rod of the cylinder device 45 is projected, the bending rollers 24 and 25 are closed, and the pipe 1 is bent.
After bending 1, the rod of the cylinder device 45 is retracted to release the bending rollers 24, 25, and a support bed (not shown) supporting the bearing 24a of the bending roller 24 has a A guide (not shown) is provided to guide the slide.

By the way, if the number of times the pipe 11 meanders during bending increases, the pipe 11 will be bent many times in the process of passing through each bending roller row 26, so depending on the material of the pipe 11, The pipe 11 may crack or become excessively distorted due to work hardening. Such work hardening occurs more easily in iron pipes than in copper pipes, for example.

In order to deal with this, for example, as in the third embodiment of the present invention shown in FIG.
7, and bending is performed at an ambient temperature that allows annealing (for example, 830° C. for iron pipes). Here, the non-oxidizing furnace 47 refers to an annealing furnace filled with an oxygen-free gas obtained by incompletely burning city gas (13A) to remove oxygen. The reason why the pipe 11 is annealed in an oxygen-free state in the non-oxidizing furnace 47 is that if the pipe 11 is annealed in an oxygen-containing atmosphere, the surface of the pipe 11 will oxidize and turn black. . And, such a non-oxidation furnace 4
If the pipe 11 is annealed in the tube 7 and bent into a meandering shape by the pipe bending device 21, the surface of the pipe 11 will be oxidized (
Pipe 11
This can prevent cracks and excessive distortion from occurring.

Each of the above embodiments is an embodiment of the pipe bending device 21 that bends the pipe 11 (heat dissipation pipe) in a meandering shape. By appropriately changing the shape, the pipe 11 can be bent into any shape. For example, when manufacturing a dew prevention pipe to be installed at the front end of the refrigerator body, bend the dew prevention pipe 48 along each curved portion as in the fourth embodiment of the present invention shown in FIG. Along with arranging the roller row 49, the dew prevention pipe 48
The pull-out rollers 50 may be arranged along the linear portions at both ends. In this case as well, the pipe 4 is placed between the bending roller rows 49.
A guide member 51 is provided to guide the guide member 8.

In addition, in the first embodiment described above, the pipe 11 wound around the uncoiler 12 was used as the raw material pipe, and the pipe 11 was cut after the bending process was completed. A straight pipe may be supplied to the pipe bending device 21 and bent.

Other aspects of the present invention include forming a guide member for guiding the pipe 11 with a cylindrical member, or arranging a dedicated feed roller as a pipe feeding device along the feeding path of the pipe 11, and furthermore, Various modifications are possible, such as application as a bending device for metal pipes of various devices other than refrigerator heat dissipation pipes and dew prevention pipes.

[Effects of the Invention] As is clear from the above explanation, according to the bending method of the present invention, the bending rollers are arranged in advance at positions matching the bending shape of the pipe, and the bending rollers are arranged in the bending roller row. Since the pipe is bent by passing the pipe through, the size of the pipe bending device can be reduced to almost the same size as the bent pipe (finished product), resulting in significant space savings. This makes it possible to significantly increase the number of pipe bending devices that can be installed in one factory (limited work space) compared to conventional methods, dramatically increasing the production capacity of the entire factory. Moreover, if the area occupied by the pipe bending device is reduced, the factory site (work space) that houses it will also be smaller, and the equipment cost can be reduced accordingly.

Furthermore, according to the pipe bending device of the present invention, the above-mentioned pipe bending method can be specifically realized, and after bending the pipe,
When taking out a bent pipe sandwiched between bending roller rows, the distance between the inner bending roller and the outer circumference bending roller can be widened by the roller release device, so that the bending roller can be removed after the pipe is bent. The formed pipe can be easily taken out from the bending roller row.

Moreover, the support bed that supports the plurality of bending rollers on the inner circumference side and the support bed that supports the plurality of bending rollers on the outer circumference side are divided, and at least one of the support beds is slid by a roller release device. Therefore, as the support bed slides, a plurality of bending rollers can be slid inside it to widen the gap between the inner bending roller and the outer bending roller. The opening configuration can be significantly simplified, contributing to cost reduction.

Furthermore, since the interval between the bending roller rows on both sides of the pipe in the meandering width direction can be adjusted by the meandering width adjusting device, meandering pipes with different meandering widths can be manufactured using a single pipe bending device. This has the advantage of making the pipe bending device more versatile.

In this case, since the length of the guide member disposed between the bending roller rows is adjustable, the length of the guide member can be adjusted to the optimum length according to the interval adjustment between the bending roller rows.
The guiding action of the pipe by the guide member between the rows of bending rollers becomes reliable, and the incidence of defects can be reduced.

[Brief explanation of the drawing]

1 to 6 show a first embodiment of the present invention, in which FIG. 1 is an overall plan view, FIG. 2 is a plan view showing the state when the bending roller is released, and FIG. 4 is an enlarged side view of the bending roller, FIG. 5 is a longitudinal side view of the guide member, and FIGS. 6(a) to (c) are diagrams for explaining the pipe bending process. It is a process diagram. FIG. 7 is a plan view of a roller opening device showing a second embodiment of the present invention, FIG. 8 is a schematic diagram of the entire configuration showing a third embodiment of the present invention, and FIG. 9 is a plan view of a roller opening device showing a second embodiment of the present invention. FIG. 1 is an overall schematic configuration diagram showing an example. FIGS. 10(a) to 10(d) are process diagrams for explaining a conventional pipe bending process. In the drawing, 11 is a pipe, 12 is an uncoiler, 13 is a leveler, 18 is a measuring roller, 20 is a cutter, 21 is a pipe bending device, 22, 22a, 22b. 23. 23a and 23b are support beds, 24 and 25 are bending rollers, 26 is a bending roller row, 28 and 29 are pull-out rollers, 30 is a chain (pipe feeding device), 31 is a cylinder device (roller opening device), and 32 is a meandering device. width adjustment device,
33 is a motor, 34 is a threaded rod, 37 is a guide member, 37a
38 is a unit guide member, 38 is a plate, 40 and 45 are cylinder devices, 46 is a roller release device, 47 is a non-oxidizing furnace, 48 is a dew prevention pipe, 49 is a bending roller row, 50 is a pull-out roller, 51 is a guide It is a member. Applicant: Toshiba Corporation

Claims (1)

[Claims] 1. A plurality of bending rollers are arranged along both the inner and outer circumferences of a bending curve that matches the bending shape of the pipe to form a bending roller row, and the pipe is attached to the bending roller row along the bending curve. A pipe bending method characterized in that the pipe is bent into the same shape as the bending curve by passing the pipe along the bending curve. 2. A bending roller row consisting of a plurality of bending rollers arranged along both the inner and outer circumferences of a bending curve that matches the bending shape of the pipe, and a bending roller row that passes the pipe through this bending roller row along the bending curve. and a roller release device that widens the gap between the inner bending roller and the outer bending roller after the pipe is bent so that the bent pipe can be taken out. A pipe bending device made of 3. The support bed that supports the plurality of bending rollers on the inner circumference side and the support bed that supports the plurality of bending rollers on the outer circumference side are divided, and the roller release device can open the plurality of bending rollers by sliding at least one of the support beds. 3. The pipe bending apparatus according to claim 2, wherein the bending roller is slid integrally with the support bed to widen the distance between the inner bending roller and the outer circumferential bending roller. . 4. A row of bending rollers is provided at a position corresponding to each bending part of the pipe so that the pipe can be bent into a meandering shape, and bending rollers on both sides in the meandering width direction are provided so that the meandering width of the pipe can be adjusted. The pipe bending device according to claim 2 or 3, further comprising a meandering width adjusting device for adjusting the spacing between the rows. 5. A guide member for guiding the pipe is provided between the bending roller rows located on both sides of the pipe in the meandering width direction,
5. The pipe bending apparatus according to claim 4, wherein the length of the guide member is adjustable in accordance with the adjustment of the interval between the bending roller rows.