JP3853534B2 - Heating and cooling device for bending metal strip - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a heating and cooling device used in a bending apparatus that continuously bends a metal strip such as a metal tube using induction heating.
[0002]
[Prior art]
Conventionally, as a metal tube bending apparatus, as shown in FIG. 7, a heating section 3 is heated by heating a small section in the tube axis direction of a metal pipe 1 to be bent to a temperature at which plastic deformation is easy with an inductor 2. A bending arm in which the metal tube 1 is moved in the direction of arrow A by moving the metal tube 1 in the direction of the arrow A by a tube moving device (not shown), and at the same time the tip of the metal tube 1 is clamped while moving the heating unit 3 in the tube axis direction. 5 is pivoted about the fulcrum O to give a bending moment to the heating unit 3 to cause bending deformation in the heating unit 3, and a cooling medium such as cooling water from the inductor 2 in a region immediately after the bending deformation is generated. The continuous bending apparatus of the structure which sprays 6 and is cooled and solidified is used.
[0003]
Normally, in this type of bending apparatus, the metal tube 1 as a whole only has a compressive force that turns the bending arm 5, so that the vicinity of the central axis PP of the metal tube is a bending neutral axis (before and after bending). Thus, the thickness is reduced on the outside of the bend, and the thickness is increased on the inside of the bend. Further, in order to prevent a reduction in wall thickness that occurs outside the bend, a structure in which a large compressive force in the tube axis direction is applied to the metal tube during bending is also known (see, for example, Japanese Patent Publication No. 54-30915). ). In this type of continuous bending process, a large compressive force acts on the inner side of the bending of the metal tube along with the bending deformation, resulting in a particularly large increase in wall thickness. Plastic deformation that causes an increase in wall thickness due to compression is unstable. Therefore, irregular deformation such as bellows is often generated. Therefore, conventionally, irregular deformation is prevented by optimizing the heating width, optimizing the heating temperature, stabilizing the heating temperature, and the like.
[0004]
[Problems to be solved by the invention]
However, in this type of bending, a large compressive force is applied to the metal tube in order to increase the thickness of the metal tube to be bent, to reduce the bending radius, or to suppress the decrease in the wall thickness outside the bending. It has been found that a problem arises when the thickness increase generated on the inner side of the bend is increased by, for example, acting on the inner side of the bend (for example, when the amount of increase in the thickness toward the outer surface of the tube exceeds 5 mm). That is, as shown in FIG. 8, when the bending process is started, the entire metal tube 1 is a straight tube, so the portion passing through the inductor 2 is at the position indicated by the two-dot chain line 1A. The inductor 2 is concentrically arranged with respect to the metal tube 1 in a state, heating and cooling are started in this state, and bending is started by feeding the metal tube 1 in the arrow A direction. Since the portion passing through 2 is bent and deformed, the tube outer surface 1a located on the inner side of the bend is displaced in a direction approaching the portion located on the inner side of the inductor 2, and the thickness increase amount generated on the outer surface of the tube on the inner side of the bend. Therefore, the pipe outer surface 1a is very close to the outlet side corner 2a of the inductor 2. For this reason, the cooling medium sprayed to the metal tube 1 from the part located inside the bending of the inductor 2 irregularly scatters, and the heating part by the inductor 2 is partially and irregularly cooled, and the temperature of the heating part However, there is a problem that the plastic deformation resistance fluctuates and the balance of bending deformation and increase in wall thickness is lost, resulting in instability and unstable deformation such as bellows.
[0005]
In order to avoid this, the portion of the inductor 2 located on the inner side of the bend is arranged so as to be separated from the metal tube 1, and even when bending deformation occurs, the outer surface 1a of the tube and the outlet side corner portion 2a of the inductor 2 are separated. It is only necessary to ensure a necessary space for blowing the cooling medium between them. However, with this configuration, the space between the inductor 2 and the metal tube on the inner side of the bend increases, and the metal tube on the inner side of the bend. In addition, there is a problem that the heating of the metal tube 1 is insufficient, and the spraying position B of the cooling medium to the straight tubular metal tube 1 at the start of bending and the spraying position C after bending are greatly different in the axial direction of the metal tube. Therefore, the cooling position moves in the transition period at the start of bending, which causes the problem that the cooling becomes unstable and unstable deformation such as bellows occurs.
[0006]
The present invention has been made in view of such a problem, and is designed to prevent bending of a strip such as a metal tube having a large thickness, bending with a small bending radius, or reduction in thickness on the outside of the bending. Providing heating and cooling devices that prevent bending and prevent bending in devices that perform bending with a large increase in wall thickness, such as bending with force. The purpose is to do.
[0007]
[Means for Solving the Problems]
In order to solve the above-described problems, the present invention provides a cooling device that sprays a cooling medium to cool a portion heated by the inductor, instead of being provided integrally with the inductor as in the prior art. Provided as a part, the cooling device is movable with respect to the inductor in a direction intersecting at least the axis of the metal strip in the bending plane, and the cooling device is a portion on the end of the bending deformation of the metal strip. It is made to move according to the displacement of . With this configuration, with the inductor fixed at an appropriate position for heating for bending, only the cooling device is used in the transition period at the start of bending, and bending deformation of the metal strip as the bending progresses. It is possible to move so as to follow the displacement of the end side portion, and the spray position of the cooling medium can always be set to a position where unstable deformation does not occur, and favorable bending can be performed.
[0008]
DETAILED DESCRIPTION OF THE INVENTION
One embodiment of the heating and cooling device of the present invention is used for continuously bending a metal strip such as a metal tube, and is arranged so as to surround the metal strip to be bent, and its axis An annular inductor that heats a small section in a direction, and an annular cooling device that is disposed adjacent to the inductor and sprays a cooling medium to a position adjacent to a heating region of the metal strip by the inductor, A cooling device movable in a direction intersecting at least the axis of the metal strip in the bending plane with respect to the child , and the cooling device crosses at least the axis of the metal strip in the bending plane with respect to the metal strip. A driving means for moving in a direction in which the metal strip is in contact with the outer surface of the outer side of the bending or inner side of the bending of the metal strip and crossing the axis of the outer surface of the metal strip. Follow the displacement of the A driven means for, to move the cooling device according to the displacement of the driven means, in which a structure having means for connecting said driven means to said cooling device.
[0009]
The metal strip to be bent using the heating and cooling device of the present invention is usually a metal tube having a circular cross section, but other than that, a rectangular tube-shaped metal tube, H-shaped steel, I-shaped steel, etc. Any shape material, round bar, square bar, etc., elongated plate, etc. are optional. The shape of the inductor for heating these metal strips may be any shape that surrounds the metal strip and can induction-heat a narrow region in the axial direction. Therefore, the term “annular” used in this specification is used. Means not only an annular shape but also a shape surrounding a strip. The same applies to the cooling device. When the metal strip is a metal tube having a circular cross section, both the heating device and the cooling device are preferably annular.
[0010]
The heating and cooling device described above is provided with driving means for moving the cooling device in accordance with the displacement of the bending deformation end portion of the metal strip , so that the bending deformation end portion of the metal strip is displaced. Accordingly, the cooling device can be moved, and the cooling medium can always be sprayed to the preferred cooling position, so that stable bending can always be performed.
[0011]
The drive means for moving the cooling device does not use a drive device such as a servo motor or a hydraulic cylinder. Instead, it comes into contact with the outer surface of the bending end or the inner side of the bending end of the metal strip, and A follower that moves following a displacement in a direction crossing the axis of the metal strip, and a means for connecting the follower to the cooling device so as to move the cooling device according to the displacement of the follower. It has a configuration with. With this configuration, the configuration of the driving means can be simplified.
[0013]
The cooling device used in the present invention may be configured to be electrically conductive over the entire circumference, but the cooling device is divided into a plurality of regions in the circumferential direction and the electrical conduction between the regions is cut off. Is preferred. In general, the cooling device is made of a conductive material such as copper or steel. Therefore, when an induced current is generated by an adjacent inductor and the annular cooling device is electrically connected over the entire circumference, A large amount of induced current that circulates around the annular cooling device is generated, and power is wasted. Therefore, by interrupting the electrical continuity by disposing an insulating material at an appropriate interval in the circumferential direction, it is possible to prevent the induction current from circulating and to suppress the induction current to be small.
[0014]
The cooling device may be configured so that the cooling medium for spraying the metal pipe flows over the entire circumference, but the cooling device is divided into a plurality of regions in the circumferential direction, and the flow between the regions is blocked to cool the respective regions. It is preferable that the medium spraying condition, for example, the spraying amount is variable. If it is set as this structure, the cooling conditions in a bending inner side, a bending outer side, and an intermediate position can be changed suitably, and the more stable bending process will be attained.
[0015]
Furthermore, it is preferable that the cooling device is configured to cool the cooling device by attaching a cooling pipe configured to pass the cooling medium separately from the passage through which the cooling medium sprayed on the metal strip is passed . As described above, since the induction current generated by the adjacent inductor is generated and heated in the cooling device, the cooling device can be prevented from being overheated by cooling with the cooling pipe.
[0016]
【Example】
Hereinafter, embodiments of the present invention will be described in more detail with reference to examples shown in the drawings. FIG. 1 is a schematic plan view of a metal pipe bending apparatus equipped with a heating / cooling apparatus 10 according to an embodiment of the present invention. FIG. 1 (a) shows a state before bending, and FIG. Indicates the state. In FIG. 1, 11 is a metal tube, PP is a central axis of the metal tube 11, and QQ is a reference axis of the bending apparatus. The metal tube 11 is set so that its central axis PP is positioned on the reference axis QQ, and one end (the left end in the drawing) is held by a tube moving device (not shown) in the direction of arrow A. It is supposed to be pushed. Reference numeral 12 denotes an annular inductor that forms a heating section 13 that is easily plastically deformed by induction heating of a small section in the tube axis direction of the metal tube 11, and a holding member 14 that also serves as a connection terminal (FIGS. 2 to 5). And a transformer for supplying high-frequency current (not shown) via a reference), and held at a predetermined position. Reference numeral 16 denotes an annular cooling device that is arranged so as to surround the metal tube 11 and blows a cooling medium (usually cooling water) 17 over the entire circumference thereof. Therefore, it is configured to be movable with respect to the inductor 12. 18 holds the cooling device 16 and moves the cooling device 16 with respect to the inductor 12 in a bending plane of the metal tube in a direction perpendicular to the tube axis direction of the metal tube 11 in the bending plane. It is a drive means, The structure is mentioned later. Reference numeral 20 denotes a bending arm that includes a clamp 21 that holds the tip of the metal tube 11 (the right end in the drawing) and that can pivot about the fulcrum O. The metal tube 11 pivots about the fulcrum O as the metal tube 11 advances. A bending moment is applied to the heating unit 13 to bend and deform.
[0017]
Next, the heating and cooling device 10 including the inductor 12 and the cooling device 16 will be described in more detail. FIG. 2 is a schematic front view of the heating and cooling device 10 viewed in the axial direction from the cooling device 16 side, and a part thereof is shown in section. FIG. 3 is a part of the heating and cooling device 10 in section. FIG. 4 is a schematic side view showing a part of the heating / cooling device 10 in section, and FIG. 5 is a schematic horizontal sectional view showing the heating / cooling device 10 in a state of bending. The inductor 12 has an annular shape surrounding the metal tube 11 and is disposed concentrically with the metal tube 11 and thus centered on the reference axis QQ. The inductor 12 is formed in a hollow structure, and the cooling water supply and discharge pipes 15 and 15 supply and discharge the cooling water.
[0018]
The cooling device 16 has an annular shape as a whole, and has an inclined surface 16a on the inner peripheral surface, and a plurality of injection holes 16b are formed in the inclined surface 16a at a constant pitch in the circumferential direction. The metal tube 11 is sprayed. Further, as can be seen from FIG. 2, the cooling device 16 is divided into a plurality of regions in the circumferential direction, and an insulating material 25 is disposed between the regions to provide conduction in the circumferential direction. It is shut off. Thereby, when the induced current by the inductor 12 is generated in the cooling device 16, the circumferential flow is partially interrupted, so that the generation of the induced current is suppressed and the energy loss can be reduced. Also, piping (not shown) for supplying a cooling medium is connected to each region of the cooling device 16, and each piping is connected to a cooling medium supply source in a form in which the flow rate can be adjusted. Has been. Thus, the discharge amount of the cooling medium 17 from each region can be individually adjusted. As can be clearly understood from FIG. 3, a cooling pipe 27 is attached in the cooling device 16 so as to be in contact with the wall surface of the cooling device 16 separately from the passage of the cooling medium sprayed on the metal pipe 11. Is connected to a pipe (not shown) for supplying a cooling medium. When the inductor 12 is energized without passing through the cooling medium for spraying the metal pipe 11 to the cooling device 16 at the time of raising the temperature of the metal pipe 11 before starting the bending process, the cooling pipe 27 is inserted into the inductor 12. 12 is used to cool the cooling device 16 that is induction-heated. Note that the piping for supplying the cooling medium to each region of the cooling device 16 and the cooling pipe 27 are also cut off at appropriate positions, and the insulation between the regions divided in the circumferential direction of the cooling device 16 is performed. The state is not damaged.
[0019]
The inductor 12 has a bending plane at both ends perpendicular to the bending plane (the plane on which the axis P-P of the metal tube 11 after bending deformation is located, the plane indicated by XX in FIGS. 2 and 4). A guide member 30 having parallel guide rails 30a is attached. On the other hand, in the cooling device 16, a guide member 32 having a guide groove 32a slidably engaged with the guide rail 30a is provided with a pin 33 and It is attached by a fixing bolt 34 or the like. Thus, the cooling device 16 is movable with respect to the inductor 12 in a direction intersecting at right angles to the axis of the metal tube 11 in the bending plane (that is, a direction connecting the bending inner side and the bending outer side, the direction of the arrow DD). is there.
[0020]
The driving means 18 for moving the cooling device 16 includes a bracket 36 attached to the holding member 14 and follower means held by the bracket 36 so as to be movable in a direction perpendicular to the axis of the metal tube 11 in the bending plane. 38. The follower 38 includes a support rod 39 that is movably held by the bracket 36, a connecting member 40 that is attached to the tip of the support rod 39, and is held by the connecting member 40 and contacts the metal tube 11. A rotating roller 41 is provided, and the connecting member 40 is connected to the cooling device 16 by a pin 43 and a long hole 44. Further, a coil spring 45 that presses the support rod 39 so as to press the roller 41 against the metal tube 11 is provided between the bracket 36 and the support rod 39. Thus, the follower means 38 is always in contact with the outer surface of the bending outer side of the bending end of the metal tube 11 (the portion that has passed through the inductor 12), and the displacement of that portion. The cooling device 16 can be moved by moving in the direction perpendicular to the axis of the metal tube 11 following the above. A temporary holding lever 47 is rotatably provided at the tip of the support rod 39 by a pin 48. When the temporary holding lever 47 is turned sideways as shown by a solid line in FIG. Although it does not interfere with the movement of the support rod 39, as indicated by a two-dot chain line 47a in FIG. Stop moving in the direction. Thereby, the roller 41 at the tip can be temporarily held so as not to interfere with the insertion operation of the metal tube 11.
[0021]
Next, the bending operation of the metal tube by the bending apparatus provided with the heating and cooling apparatus 10 having the above configuration will be described. First, as shown in FIG. 1A, the metal tube 11 to be bent is set at a predetermined position on the machining axis QQ, and the inductor 12 is concentric with the metal tube 11. Position to. When the metal tube 11 is set, the temporary holding lever 47 of the driving means 18 is set to a position indicated by a two-dot chain line 47a in FIG. 2, and the support rod 39 and the rollers 41 and the cooling device 16 held by the support rod 39 are used for inserting the metal tube 11. Temporarily held at a position where it does not interfere. After setting the metal tube 11, the temporary holding lever 47 is rotated to the position indicated by the solid line in FIG. 2 to release the temporary holding of the support rod 39, and the tip roller 41 is pressed against the metal tube 11. As a result, the cooling device 16 is positioned at a position where the roller 41 at the tip of the follower 38 is in contact with the metal tube 11. Here, the position of the cooling device 16 at this time is determined to be concentric with the metal tube 11.
[0022]
In this state, energization of the inductor 12 is started, and a heating section 13 is formed by heating a small section in the tube axis direction of the metal tube 11 located inside thereof, and the heating section 13 is set to a temperature at which plastic deformation is easy. When the temperature rises, injection of the cooling medium 17 from the cooling device 16 is started and movement of the metal tube 11 in the direction of arrow A is started. As a result, the bending arm 20 that clamps the tip of the metal tube 11 starts to turn around the fulcrum O, and the turning applies a bending moment to the heating unit 13 to cause the heating unit 13 to bend and deform. The region immediately after the generation is cooled and solidified by the cooling medium 17 from the cooling device 16. Thereafter, as the metal tube 11 is continuously fed in the direction of arrow A, the metal tube 11 is continuously bent as shown in FIG. When this bending process is started, as shown in FIG. 5, the portion on the tip side of the heating portion 13 of the metal tube 11, that is, the portion on the bending deformation end side is bent by the bending arm 20. Both the outer surface 11b and the outer surface 11b of the bending are displaced toward the bending center side in a direction crossing the central axis PP of the straight tube portion of the metal tube 11. In particular, since the wall thickness increases along the inside of the bend, the outer surface 11a is further displaced toward the bend center. However, as shown in FIGS. 1B and 5, the follower 38 is pressed against the outer surface 11 b of the metal tube 11 through the roller 41, so that the follower 38 is the outer surface of the metal tube 11. It moves following the displacement of 11b, and the cooling device 16 also moves toward the bending center side. Thus, on both the inner side and the outer side of the bend, an interval for enabling stable cooling is ensured between the injection hole 16b of the cooling medium of the cooling device 16 and the outer surface 11a, 11b of the metal tube. Bending is continued. In this way, good cooling can always be performed during the bending process, and a stable bending process is performed.
[0023]
Here, the amount of movement of the cooling device 16 is determined by the position (the distance in the axial direction from the inductor 12) where the roller 41 of the driven means 38 contacts the outer surface of the metal tube. The amount of movement can be adjusted. Generally, in order to perform the bending process of the metal tube 11 stably, it is necessary to stabilize the cooling inside the bending. In other words, the inner side of the bend is compressed along with the bend, resulting in an increase in the thickness. Therefore, unstable deformation such as bellows tends to occur, and cooling is important to prevent this unstable deformation. Therefore, when setting the amount of movement of the cooling device 16, the distance between the cooling medium injection hole 16b of the cooling device 16 and the outer surface 11a of the metal tube so that good cooling inside the bend can be performed through experiments or the like. What is necessary is just to set so that the space | interval may be obtained.
[0024]
In addition, in the said Example, although it is the structure which makes the follower 38 follow the outer surface 11b of the bending outer side of the metal tube 11, it is good also as a structure to follow the outer surface 11a of a bending inner side instead. Further, the movement of the driven means 38 is directly transmitted to the cooling device 16, but instead, the movement of the driven means 38 may be enlarged or reduced and transmitted to the cooling device 16.
[0025]
Although the said Example is a structure which moves the cooling device 16 in parallel with respect to the inductor 12, as shown in FIG. 6, the cooling device 16 is inclined with respect to the inductor 12 in a bending plane, or a metal strip. It is also possible to adopt a configuration that can be moved along the axis. In other words, the angle θ of the cooling device 16 with respect to the inductor 12 and the distance in the axial direction can be adjusted. By changing this angle θ, the heating width on the inner side and the outer side of the bending can be adjusted independently, and the bending deformation can also be stabilized by this adjustment. When the angle θ or the like of the cooling device 16 with respect to the inductor 12 can be adjusted as described above, this adjustment may be performed only by manual adjustment, or may be configured to be moved by appropriate driving means. Further, even when the angle θ can be adjusted, the cooling device 16 may be configured to be movable in the direction crossing the axis line PP of the metal tube 11.
[0026]
【The invention's effect】
As described above, according to the present invention, the cooling device can be moved in the bending plane at least in the direction crossing the axis of the metal strip with respect to the inductor, and the bending deformation end portion of the metal strip. In the state where the inductor is fixed at a position suitable for heating for bending with respect to the metal strip, only the cooling device is used in the transition period at the start of bending. The metal strip can be moved to follow the displacement of the end of the bending deformation of the metal strip as the bending progresses, and the cooling medium spraying position should always be a position where unstable deformation does not occur. It is possible to perform a satisfactory bending process, and in particular, it is possible to stably carry out a bending process in which a large thickness increase occurs inside the bending.
[Brief description of the drawings]
FIG. 1A is a schematic plan view showing a bending apparatus for a metal tube provided with a heating and cooling device according to an embodiment of the present invention, in a state before bending, and FIG. FIG. 2 is a schematic front view of the heating and cooling device shown in FIG. 1 as viewed from the cooling device side. FIG. 3 is a schematic plan view of the heating and cooling device shown in FIG. Fig. 5 is a schematic side view of the heating and cooling apparatus shown in Fig. 5. Fig. 6 is a schematic horizontal sectional view of the heating and cooling apparatus shown in Fig. 4 in a state during bending. FIG. 7 is a schematic plan view showing a conventional bending apparatus. FIG. 8 is a diagram for explaining a problem caused by the conventional apparatus. Schematic cross section shown 【Explanation of symbols】
DESCRIPTION OF SYMBOLS 10 Heating and cooling apparatus 11 Metal pipe 12 Inductor 13 Heating part 14 Holding member (connection terminal)
16 Cooling device 16b Injection hole 17 Cooling medium 18 Driving means 20 Bending arm 21 Clamp 25 Insulating material 27 Cooling pipe 36 Bracket 38 Drive means 39 Support rod 40 Connecting member 41 Roller

Claims (4)

Arranged so as to surround the metal strip to be bent, an annular inductor for heating a small section in the axial direction thereof, a position adjacent to the inductor, and a position adjacent to the heating area of the metal strip by the inductor an annular cooling device for blowing cooling medium to a cooling device movable in a direction intersecting at least the axis of the metal strip material in a plane bending with respect to the inductor, the cooling device to the metal strip material On the other hand, it has a drive means for moving in the direction intersecting at least the axis of the metal strip in the bending plane, and the drive means hits the outer side of the bending outer side or the inner side of the bending of the metal strip. A follower that moves in accordance with a displacement in a direction intersecting the axis of the metal strip on the outer surface of the metal strip, and the follower is moved in accordance with the displacement of the follower. Connected to Heating bending and having a means for a cooling device. The heating and cooling device for bending a metal strip according to claim 1, wherein the cooling device is divided into a plurality of regions in the circumferential direction and electrical conduction between the regions is interrupted . The heating and cooling device for bending a metal strip according to claim 1 or 2, wherein the cooling device is divided into a plurality of regions in the circumferential direction, and cooling medium spraying conditions in each region are variable . 4. The cooling device according to claim 1, wherein a cooling pipe configured to pass a cooling medium is attached to the cooling device separately from a passage through which the cooling medium sprayed on the metal strip is passed, and the cooling device is cooled. A heating / cooling device for bending a metal strip according to any one of the preceding claims.

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