JP2013111590A - Device for bending metallic bar material, supporting clamp device for preventing neck breakage, and method for manufacturing the metallic bar material having bent part - Google Patents

Abstract

PROBLEM TO BE SOLVED: To avoid labor and danger in work and prevent a neck breakage during bending work while securing excellent productivity.SOLUTION: The device for bending a metallic bar material includes: a means for heating the metallic bar material; a means for thrusting the metallic bar material; and a clamp arm for clamping the metallic bar material and applying bending moment to the metallic bar material by turning with a spindle as the center accompanying the thrust of the metallic bar material. The device for bending a metallic bar material also includes a supporting clamp abutting on a surface of the metallic bar material at a near position further at the rear side of a clamping part of the clamp arm and inhibiting neck breaking deformation of the metallic bar material. The supporting clamp includes an outer claw capable of performing opening and closing operations between a closed state abutting on an outer peripheral side surface of a bent portion of the metallic bar material and an opened state separating from the outer peripheral side surface of the bent portion, and an inner claw capable of performing opening and closing operations between a closed state abutting on an inner peripheral side surface of the bent portion of the metallic bar material and an opened state separating from the inner peripheral side surface of the bent portion.

Description

  The present invention relates to a bending apparatus for a metal strip, a support clamp device for preventing neck breakage, and a method for manufacturing a metal strip having a bent portion, and in particular, when bending a metal strip such as a steel pipe. The present invention relates to a technique capable of preventing bending deformation (so-called neck bending) of the strip material that may occur.

  Metal strips are widely used today as pipes for transporting fluids such as oil, gas, and various liquids in industrial facilities such as plants, factories, and power plants, or as framework structures for civil engineering buildings such as bridges and stadium roofs. . Steel pipes (metal pipes), which are one of these metal strips, are standardized pipes with a predetermined shape (straight pipes or deformed pipes such as elbows and bends). Pipes obtained by bending a tubular pipe (hereinafter referred to as “bend pipes”) are widely used because they can flexibly meet the demands for various curvatures and pipe shapes.

  In general, a processing apparatus for manufacturing such a bending pipe grips a metal tube, an induction heating coil that annularly heats a part of the metal tube to be processed, a propulsion mechanism that propels the metal tube toward the induction heating coil, and the like. And a clamp arm that restricts the path of the metal tube in an arc shape by turning around the support shaft. In processing, the metal tube is pushed toward the induction heating coil while holding the front end side (tube tip side) of the induction heating coil of the metal tube by the clamp arm. The clamp arm revolves around the support shaft as the metal tube is propelled. This causes a bending moment to be applied to the heated portion of the metal tube by the induction heating coil, and the metal tube is continuously plastically deformed to draw an arc. Can be bent like

  In addition, when manufacturing a bent pipe, simply bending a straight pipe as a raw material reduces the pipe thickness (thickness) on the outer peripheral side of the bent pipe portion, and does not satisfy the required strength and specifications for the pipe. There is a fear. Therefore, in addition to the bending moment, there is a case where a processing is performed to apply a compressive force in the direction of the tube axis by applying a force in the direction of pulling back the clamp arm to prevent a reduction in thickness (thinning). In addition, as described above, the process of simply bending a straight pipe by only the bending moment by the clamp arm without applying a compressive force is called "simple bending", whereas the bending process performed while applying compressive force in this way Is sometimes referred to as “compression bending”.

  On the other hand, in the bending process as described above, a so-called neck break may occur in which the metal strip to be processed is deformed so as to be bent near the portion gripped by the clamp arm. This neck breakage is caused by thrust for propelling the metal strip and compression force in compression bending, and a large bending moment is applied near the gripping portion by the clamp arm, in particular, the bending angle becomes large (for example, It tends to occur as it is bent at 90 °, and is more likely to occur in compression bending than simple bending.

  For this reason, various proposals for preventing the above-described neck breakage have been conventionally made (see the following patent document).

JP 2010-245841 A JP 2011-125907 A

  By the way, the conventional neck breakage prevention technology still has room for improvement in terms of work efficiency at the time of processing (productivity of bent pipe) and avoidance of danger at the time of work.

  Specifically, the technique of Patent Document 1 prevents neck breakage by attaching an attachment that comes into contact with the outer peripheral surface of the metal strip to be processed to the clamp arm (preceding side clamp 48). Since this attachment is attached manually during the bending process, it cannot be said that the working efficiency is good, and further provision of technology is desired from the viewpoint of productivity. In addition, this attachment requires high rigidity that can resist neck deformation caused by propulsive force of several tens of tons, so there is a limit to weight reduction. Especially, the tube diameter is several tens to several meters. If this happens, the size of the attachment will increase accordingly, and the mounting work will be heavy labor. In addition, the induction heating coil that heats the metal pipe to a high temperature is in operation during bending, and the cooling water that cools the metal pipe is also in the injection state, and the work environment when attaching the attachment is severe and sufficient for safety. Consideration is required.

  On the other hand, in the technique of Patent Document 2, an instrument (in-tube insertion diameter increasing mechanism) that abuts the inner surface of a metal tube to be processed is inserted into the tube from the tip of the metal tube, and the metal tube is supported from the inner side. This is to prevent breakage. However, even with this instrument, it is basically necessary for an operator to approach the metal tube and operate the instrument (handle 51) during the bending process. Further, since the instrument is mounted so as to cover the tip of the metal tube, after bending a certain section, the clamp by the clamp arm is changed (re-gripped) to further bend the metal tube in a different direction. In such a case (when the bending direction is changed in the middle, such as so-called S-shaped bending or three-dimensional bending), there is a difficulty that cannot cope with this.

  Therefore, the object of the present invention is to reduce and avoid work effort and risk, prevent occurrence of neck breakage during bending while ensuring good productivity, and can also be used for bending with changing clamps. It is in the point which provides a simple neck break prevention means.

  In order to solve the above-mentioned problems and achieve the object, the metal strip bending apparatus according to the present invention has the propulsion direction of the metal strip as the bending object as the front and the direction opposite to the propulsion direction as the rear. In this case, a heating means for annularly heating a part of the metal strip, a propelling means for propelling the metal strip toward the heating means, and a front side of the heating portion of the metal strip by the heating means are gripped And a clamp arm that is pivotally supported by a support shaft and pivots about the support shaft to apply a bending moment to the metal strip as the metal strip is propelled by the propulsion means. An apparatus for bending a material, comprising a support clamp that abuts against the surface of the metal strip at a position close to the rear side of the grip point by the clamp arm and prevents neck deformation of the metal strip.

  In the bending apparatus of the present invention, the strip is heated while annularly heating a part of the metal strip by the heating means, and at the same time, the metal strip passing through the heating means by the clamp arm curves in an arc. Guide you to do. Specifically, a portion in front of a portion (heating portion) heated by the heating means is gripped by a clamp arm. The clamp arm is installed so as to be rotatable about a support shaft, and is rotated as the metal strip is propelled by the propulsion means. Accordingly, the grip portion of the metal strip by the clamp arm is By turning around the support shaft, a bending moment is applied to the heating portion of the metal strip, and thereby the metal strip can be bent continuously so as to draw an arc by plastic deformation.

  On the other hand, in the present invention, deformation of the metal strip is restricted by the support clamp during bending, and bending is prevented. That is, the support clamp comes into contact with the surface of the metal strip at a position close to the clamp arm on the rear side (base end side of the metal strip) from the gripping portion by the clamp arm. Suppresses desired deformation and prevents neck deformation of the metal strip.

  As a specific structure of the support clamp, an outer claw capable of opening and closing between a closed state in which the metal strip is in contact with the bent outer peripheral surface and an open state in which the metal strip is separated from the bent outer peripheral surface. The outer claw is pressed against the outer circumferential surface of the metal strip to prevent deformation of the metal strip. Further, in a typical aspect of the present invention, in addition to the outer claw, the metal strip is opened and closed between a closed state in contact with the inner surface on the bending inner side and an open state separated from the inner surface on the bending inner side. An operable inner claw is further provided, and the deformation of the metal strip is similarly suppressed by gripping the metal tube with the outer claw and the inner claw. As the bending process is applied, a tensile force is applied to the outer peripheral side of the bend. May be referred to as each.

  As described in the above-mentioned patent document, neck bending in bending is caused by deformation of the metal strip so that it is bent at a position close to the rear side of a clamp that holds the front side of the metal strip (a front clamp described later). According to the support clamp structure of the present invention, the rear side proximity position of the front clamp where the deformation is likely to occur can be supported by the outer claws, so that such neck bending deformation can be suppressed satisfactorily. Furthermore, in an apparatus having an inner claw, the metal strip can be gripped by the outer claw and the inner claw, and can be gripped so as to wrap the metal strip, thereby increasing the cross-sectional strength of the metal strip during processing, and more It is possible to reliably prevent the neck from being bent and to prevent the flattening of the tube.

  Further, in the above support clamp, the outer and inner claws can be opened and closed by a driving means such as a hydraulic cylinder or an electric motor, for example. The inefficiency of work efficiency can be eliminated and the danger at the time of work can be avoided. Furthermore, the support clamp of the present invention is to be brought into contact with the surface (side surface) of the metal strip, and does not have to be attached to the tip of the metal strip like a conventional neck breakage prevention device. It is also possible to cope with a bending process that involves changing the clamp arm, such as so-called S-shaped bending or three-dimensional bending.

  It is not always necessary to use the support clamp during processing (contact with the metal strip) (although it may be always used during processing), for example, the bending angle is small and the neck is not easily broken. In the initial stage of bending, it may not be used as an open state. Also, for example, when the tube is thick, when the bending angle is small, or when the bending radius is large, it is difficult to cause neck breakage. Processing is also possible.

  Also, in one aspect of the present invention, the heating means is movable in the front-rear direction toward the clamp arm, and the outer claw (in the aspect having the inner claw, the same applies to the inner claw) is capable of the opening / closing operation. Therefore, the support clamp is supported so as to be rotatable about a rotation support shaft provided at the base end portion, and the support clamp can accommodate the heating means between the support clamp and the metal strip in the open state. The outer claw (or outer claw and inner claw) and the rotation support shaft are installed so that a gap is formed between the metal strip. In an apparatus having an outer claw and an inner claw, both claws are typically supported by the same (single) rotating support shaft, but the outer claw and the inner claw are respectively supported by separate rotating support shafts. It does not matter.

  As described above, the gap is formed between the support clamp and the metal strip so that the heating means can be accommodated in the open state. The support clamp disposed on the rear side of the clamp arm obstructs the heating means. This is to prevent the heating means from being moved (so that the heating means can be arranged at a position close to the clamp arm) and to move the heating means forward to a position close to the clamp arm at the start of processing. According to the above, the following bending process called gradation bending can be performed.

  Rather than bend the metal strip with a constant curvature from the beginning to the end of the bending process, it is known that neck bending will not easily occur if gradation bending is performed by gradually changing the bending radius at the beginning and end of bending. . In this gradation bending, (1) at the initial stage of bending (beginning of bending), the bending radius is infinite (straight line) to a predetermined bending radius (distance from the pivot that is the pivot center of the clamp arm to the clamp point of the metal tube) Bending radius determined by the turning radius, which will be referred to as “steady bending radius”, is gradually reduced. (2) A constant bending radius (steady bending radius) in the intermediate stage of processing (steady bending) ), And (3) at the end of bending (end of bending), the bending radius is gradually increased from the steady bending radius. It is possible to form a smooth bending material (a pipe line in the case of a metal pipe) whose curvature gradually changes from a grip portion by the front clamp and an unprocessed portion at the rear of the metal material to a curved portion having a predetermined curvature.

  Here, if the said aspect is employ | adopted, since the clearance gap which can accommodate a heating means is formed between a support clamp and a metal strip in an open state, a heating means is approached to a clamp arm (front clamp) at the beginning of bending. Although it can be moved to a position and provided with a support clamp that can come into contact with the clamp arm proximity position, it can be bent by heating to the clamp arm proximity position. Neck breakage occurs when a bending moment is applied to the position closest to the rear side of the gripping part (clamp part) by the clamp arm due to the thrust of the metal strip, and this bending moment (referred to as “clamping moment”) is processed. Therefore, there is no problem even if the support clamp is opened as described above at the initial stage of processing.

  Further, although the bending moment due to the thrust is constant, the above clamping moment is (1) the greater the distance between the bending point P and the front clamp 36 (see FIG. 1 described later), and (2) Thus, as the processing progresses and the bending angle increases (especially when the angle is 45 ° or more), and (3) the thickness reduction rate becomes smaller and approaches 0%, it becomes larger and neck breakage is more likely to occur. In the present invention, gradation bending is not essential, and it is of course possible to perform normal bending without performing the above-described processing in gradation bending before and after the processing.

  Further, in the above aspect, the rotation support shaft that supports the outer claw is disposed above the loading position of the metal strip, and the outer claw is positioned above the loading position of the metal strip in the open state of the support clamp. It is preferable that

  This is to make it easier to take out the metal strip from the processing apparatus after the processing is finished (or after the bending of a certain section is finished in the case of performing S-shaped bending or three-dimensional bending). According to the preferable aspect as described above, both the outer claw and the rotating support shaft that supports the outer claw are disposed at a position higher than the metal strip, so that the outer claw and the rotating support shaft interfere with the work of taking out the metal strip. Therefore, the metal strip can be removed by moving it horizontally (to the tip end side of the clamp arm (in the direction opposite to the support shaft)) horizontally.

  Further, in a device including both an outer claw and an inner claw as a support clamp, the inner claw is narrower in the front-rear direction than the outer claw, so that the front surface of the inner claw and the front surface of the outer claw are substantially in the same position in the front-rear direction. In addition, it is preferable that the inner nail and the outer nail are configured so that the rear surface of the inner nail is positioned in front of the rear surface of the outer nail.

  On the inner side of the bend (compression side), the surface of the metal strip rises toward the center of bending (for example, in the case of a metal tube, the tube surface protrudes / swells toward the support shaft side due to increase in thickness / thickness of the tube). However, there is a case where such a deformation on the compression side is released and a margin for accommodating the deformation is provided.

  For the same reason, a tapered surface may be formed on the inner surface of the inner claw, which is a surface in contact with the metal strip, so as to gradually move away from the surface of the metal strip as going backward. The formation of the tapered surface may be applied to a structure in which the width and the rear surface position of the outer claw and the inner claw in the front-rear direction are the same, or the width and rear surface position of the outer claw and the inner claw as described above. You may carry out in the structure which made these differ.

  Furthermore, you may provide the press stopper which presses the front-end | tip part of an outer nail | claw in a closing direction in a closed state, and prevents rotation to the open direction of an outer nail | claw. This is for preventing the neck from being deformed more reliably by the pressing stopper. As this pressing stopper, for example, a hydraulic cylinder can be used.

  Moreover, when providing the said press stopper, it is preferable to arrange | position this below the loading position of a metal strip. This is because the pressing stopper does not get in the way when the metal strip is taken out as described above.

  Further, a crush prevention stopper may be further provided that abuts the tip of the outer claw in the closed state and prevents excessive rotation of the outer claw in the closing direction. This is to eliminate the possibility that the outer claws that require a large supporting force against the neck breakage deformation may undesirably deform the metal strip to be processed. If such a crush prevention stopper is provided, excessive (unnecessary) rotation of the outer claws can be prevented, and a necessary and sufficient supporting force to resist neck deformation can be applied to the metal strip. .

  Further, the machining apparatus of the present invention compares the turning angle detected by the bending angle detecting means for detecting the turning angle of the clamp arm with a predetermined value, and the turning angle is determined in advance. You may further provide the control part which makes the said outer nail | close state closed when it becomes a defined value.

  According to such an apparatus configuration, when the metal strip reaches a predetermined bending angle, the control unit operates the support clamp via the support clamp drive unit (for example, a hydraulic cylinder) without manual intervention, and the external It is possible to prevent the neck from breaking by closing the nail. The above-mentioned predetermined value should be set in advance so that neck breakage can be prevented corresponding to the material, diameter, thickness, required reduction rate, etc. of the metal strip to be processed. It ’s fine.

  In the processing apparatus according to the present invention, there is provided compression means for applying a compressive force to the metal strip by applying a pull back force to pull the clamp arm in the direction opposite to the turning direction of the clamp arm accompanying the propulsion of the metal strip. There may be further provisions. As described above, the neck breakage is more likely to occur when compressive bending is performed compared to simple bending, but the present invention can be preferably applied to a processing apparatus including the compression means as described above. It is possible to effectively prevent neck breakage that tends to occur in compression bending.

  Further, the support clamp device for preventing neck break according to the present invention includes a heating means for annularly heating a part of the metal strip material to be bent, and a propelling means for propelling the metal strip toward the heating means, The metal strip is held in front of the heating section by the heating means and supported by the support shaft so as to be pivotable, and the metal strip is swung around the support shaft and bent into the metal strip as the propelling means propels the metal strip. A clamp device that can be mounted on a bending device provided with a clamp arm that applies a moment, and is in a closed state in contact with the surface on the bending outer periphery side of the metal strip at a position close to the rear side of the grip point by the clamp arm And an outer claw capable of opening and closing between the metal strip and an open state separated from the outer peripheral surface of the metal strip, and a fixing means for fixing the outer claw to the clamp arm.

  The support clamp device according to the present invention has the same function as the support clamp provided in the bending device of the present invention, but can be mounted on the bending device by the fixing means. Can be added to an existing (conventional) bending apparatus.

  Further, in the support clamp device, the closed state in which the metal strip is in contact with the surface on the inner side of the bending at a position near the gripping point by the clamp arm and the surface on the inner side of the bending of the metal strip are separated from each other. An inner claw that can be opened and closed between the open state and the fixed state may be further provided. In this case, the fixing means can fix the inner claw to the clamp arm together with the outer claw.

  Furthermore, the manufacturing method of the metal strip provided with the curved portion according to the present invention has the same characteristics as those of the bending apparatus and the support clamp device of the present invention, and a part of the metal strip is heated in an annular shape. And a manufacturing method of a metal strip that plastically deforms at least a part of the metal strip into a curved state by applying a bending moment to the heating section, and grips the position in the vicinity of the heating section of the metal strip. The metal strip is gripped by a clamp arm that can be pivoted about a support shaft that is separated from the gripping portion by a certain distance, and the metal strip is propelled in the direction of the axis of the metal to rotate the gripping portion by the clamp arm. When the metal strip is propelled in the forward direction and the direction opposite to the propulsive direction is the rear, the clamp arm During the guide of the metal strip, the support clamp is brought into contact with the surface of the metal strip at least on the outer periphery side of the metal strip at a position close to the rear side of the grip portion of the metal strip by the clamp arm, thereby preventing neck deformation. However, the metal strip is bent.

  Also in this manufacturing method, an outer claw that can be opened and closed is supported between a closed state in contact with the bent outer peripheral surface of the metal strip and an open state separated from the bent outer surface of the metal strip. When the clamp arm is included in the clamp and pivoted at a predetermined angle, the outer claw can be closed and brought into contact with the bent outer peripheral surface of the metal strip.

  Furthermore, an inner claw capable of opening and closing between the closed state in which the support clamp is in contact with the surface on the bending inner peripheral side of the metal strip and the open state separated from the surface on the bending inner peripheral side of the metal strip. When the clamp arm is turned at a predetermined angle, the inner claw can be closed and brought into contact with the bending inner peripheral surface of the metal strip.

  The metal strip to be processed in the present invention is typically a metal hollow tube, but is not limited thereto, and may be, for example, a solid tube, H steel, angle steel, or the like. It may be a long member. The embodiment described later is for a metal tube having a circular cross section, and therefore the shape of the clamp arm (front clamp) and the holding portion of the support clamp is matched to the shape of the metal tube. In the case where the metal strip has another cross-sectional shape, the shape of the clamp arm (front clamp), the rear clamp, and the holding portion of the support clamp may be appropriately changed according to the shape of the processing target.

  Further, the material and dimensions (outer diameter, inner diameter, wall thickness, etc.) of the metal strip are not limited to specific ones. For example, the present invention typically deals with pipes made of materials mainly made of iron (for example, steel pipes, stainless steel pipes, special steel pipes, etc.), but pipes and other metal alloys mainly made of other metal materials. It may be a tube made of a material. Furthermore, in the present invention, the part to be bent (curved part or curved pipe part) may be a part or the whole of the entire length of the strip.

  According to the bending apparatus for a metal strip according to the present invention, it is possible to avoid the labor and risk of work and to prevent neck breakage in bending while ensuring good productivity.

  Other objects, features, and advantages of the present invention will become apparent from the following description of embodiments of the present invention described with reference to the drawings. In addition, in each figure, the same code | symbol shows the same or an equivalent part.

FIG. 1 is a plan view conceptually showing a bending apparatus according to an embodiment of the present invention (shown in a state rotated 90 ° counterclockwise when FIGS. 4 to 7 described below are front views). is there. FIG. 2 is a plan view conceptually showing a state during processing of the bending apparatus according to the embodiment, similarly to FIG. FIG. 3 is a perspective view conceptually showing a front end portion (clamp arm portion) of the bending apparatus according to the embodiment. FIG. 4 is a front view showing a clamp arm portion (a state in which the front clamp is closed) of the bending apparatus according to the embodiment. FIG. 5 is a front view showing a clamp arm portion (a state where the front clamp is opened) of the bending apparatus according to the embodiment. FIG. 6 is a front view (a view seen from X1-X1 in FIGS. 1 and 3) of the support clamp portion for preventing neck breakage of the bending apparatus according to the embodiment, showing a state in which the support clamp is closed. ing. FIG. 7 is a front view (a view seen from X1-X1 in FIGS. 1 and 3 similarly to FIG. 6) showing a support clamp portion for preventing neck breakage of the bending apparatus according to the embodiment. It shows the open state. FIG. 8 is a side view showing the support clamp portion for preventing neck breakage (as viewed from X2-X2 in FIG. 6) of the bending apparatus according to the embodiment. FIG. 9 is a side view showing a support clamp portion for preventing neck breakage (as viewed from X3-X3 in FIG. 6) of the bending apparatus according to the embodiment. FIG. 10 is a perspective view showing a schematic configuration of the support clamp (the inner claw is not shown). FIG. 11 is a plan view conceptually showing a bending start process by the processing apparatus of the embodiment, and shows a state in which the induction heating coil is brought close to the clamp arm with the support clamp opened. FIG. 12 is a plan view conceptually showing a state during processing (support clamp is closed) by the processing apparatus of the embodiment. FIG. 13 is a plan view illustrating a modified example of the support clamp of the processing apparatus according to the embodiment in the same manner as in FIGS. 11 to 12. FIG. 14 is a view showing a cross-sectional state (tube thickness state) of the metal tube at a position in the vicinity of the grip portion by the clamp arm and the support clamp of the embodiment.

  A bending apparatus according to an embodiment of the present invention is an apparatus that bends a metal tube 11 as a metal strip to be processed. As shown in FIGS. 1 to 3, a part of the metal tube 11 to be processed. An induction heating coil 12 (hereinafter sometimes simply referred to as “coil”), a propulsion mechanism 14 for propelling the metal tube 11 toward the induction heating coil 12, and a front portion of the metal tube 11 A clamp arm 31 that imparts a bending moment to the metal tube 11 by rotating around the support shafts 35 and 35 a as the metal tube 11 is propelled, and a support clamp 51 that prevents the neck tube from being deformed by gripping the metal tube 11. And a compression mechanism 21 that generates a pulling force D in the direction opposite to the propulsion of the metal tube 11 and applies a compression force to the metal tube 11, and these are mounted on the apparatus frame 25 (see FIG. 3). What A.

  1 and 3 show the front, rear, left, right, and up and down directions, and the following embodiments will be described based on these directions. Moreover, the symbol P in the figure indicates the arrangement position of the induction heating coil 12 at the time of steady bending (hereinafter referred to as “steady position”), and the metal tube 11 is bent at this position. This is called “bending point”.

  As shown in FIG. 3, the apparatus frame 25 includes a bottom plate-like main body frame 26 and a columnar frame 27 that rises vertically upward from the main body frame 26, and a clamp arm 31 is rotatably installed on the columnar frame 27.

  Specifically, the clamp arm 31 includes two arm rods 32 that are arranged vertically so as to extend in the left-right direction, which is a direction orthogonal to the propulsion direction A (front) of the metal tube 11 to be processed, and in parallel with each other. , 33, a support column 34 that extends in the vertical direction and connects the arm rods 32, 33, and a front clamp 36 that holds the metal tube 11 at a position in front of the induction heating coil 12. Of the two arm rods 32 and 33, the upper arm rod 32 is referred to as an “upper rod” and the lower arm rod 33 is referred to as a “lower rod”.

  The upper rod 32 is rotatably attached to the columnar frame 27 via a support shaft 35, and the lower rod 33 is rotatably attached to the main body frame 26 via a support shaft 35a. The metal tube 11 held by the front clamp 36 is moved forward. When propelled (see arrow A), the clamp arm 31 receives this propulsive force and rotates horizontally around the support shafts 35 and 35a (see arrow B), and the front clamp 36 grips the metal tube 11. Swivels to draw an arc around the support shafts 35, 35a. Along with this, a bending moment is applied to the metal tube 11 held by the front clamp 36, and the portion heated by the coil 12 is bent one after another (at the bending point P), and the metal tube 11 is bent into an arc shape. (See FIG. 2).

  On the other hand, the sprocket 24 is fixed to the lower rod 33, and the sprocket 24 rotates together with the clamp arm 31 (lower rod 33) around the support shaft 35a of the clamp arm 31 (see arrow C). The sprocket 24 constitutes the compression mechanism 21 together with the chain 23 that meshes with the sprocket 24 and the compression drive unit 22 that generates the pullback force D that pulls the chain 23 in the direction opposite to the propulsion direction of the metal tube 11 (rearward). With the rotation of the clamp arm 31 accompanying the propulsion of the metal tube 11, the sprocket 24 rotates and winds up the chain 23, but a force (retraction force backward) D against this is applied by the compression drive unit 22 to the chain 23. And by applying to the clamp arm 31 via the sprocket 24, a compressive force that prevents thinning is applied to the metal tube 11. This enables compression bending. The compression drive unit 22 may be constituted by, for example, a hydraulic cylinder.

  In the drawing, the support column 34 and the arm rods 32 and 33 are depicted as an integral continuous structure. However, the support column 34 can be moved relative to the arm rods 32 and 33, that is, the arm. The clamp arm 31 can be installed along the rods 32 and 33 so that the position of the clamp arm 31 can be changed in the length direction (in the left-right direction) (the moving mechanism is not shown). By moving the front clamp 36 and the support clamp 51 fixed to the support column 34 to the left and right along the clamp arm 31 together with the support column 34, the metal tube can be bent at various bending radii by approaching or moving away from the support shafts 35 and 35a. Bending can be performed. In this case, a pressing stopper 56 and a crush prevention stopper 57 which will be described later are also fixed so as to be integrated with the support portion 34 so that they are moved together with the support clamp 51 (support portion 34).

  The propulsion mechanism 14 that propels the metal tube 11 includes a rear clamp 15 that grips the rear portion of the metal tube 11 and a propulsion drive unit 16 that applies a forward propulsive force A to the metal tube 11 through the rear clamp 15. The propulsion drive unit 16 is configured by, for example, a hydraulic cylinder, similarly to the compression drive unit 22.

  The propulsion mechanism 14 and the compression mechanism 21 are not particularly limited to a specific structure, and the propulsion mechanism 14 in the present invention is capable of propelling the metal tube 11, and the compression mechanism 21 is a metal. Any structure may be used as long as it can apply a compressive force for suppressing the thinning to the tube 11, and the structure is not limited to the illustrated embodiment.

  The induction heating coil 12 that heats the metal tube 11 is disposed behind the clamp arm 31 and is driven by a drive unit (not shown). The drive unit includes a power source that supplies power to the coil 12 and a moving mechanism that moves the coil 12. The drive unit moves the coil 12 in the front-rear direction along the axial direction of the metal tube 11. Is possible. Further, a cooling mechanism capable of injecting cooling water so that the metal pipe can be cooled immediately after bending (the cooling mechanism itself is not shown, but the cooling water injected from the cooling mechanism is denoted by reference numeral 10 in FIGS. 2 and 12. )) Is provided integrally with the induction heating coil 12, and at the time of processing, the cooling water 10 is sprayed toward the surface of the metal tube immediately in front of the coil 12 to cool the heated and bent metal tube. Reference numeral 13 in the drawing denotes a guide roller for guiding the metal tube 11.

  4 to 5, the front clamp 36 is configured to receive a metal tube 11 formed on the side surface of the support column 34 of the clamp arm 31 and to be rotatable relative to the tube receiver 37. A gripping claw 38 is provided, and the metal tube 11 can be sandwiched (gripped) by the tube receiving portion 37 and the gripping claw 38 so as to be gripped. The gripping claw 38 is rotatably supported by a support shaft 39 provided near the upper position of the metal tube 11, and can be opened and closed (turned) by a hydraulic cylinder 41 as shown in FIGS. . The front clamp 36 is a hydraulic cylinder that presses the distal end (lower end) of the gripping claw 38 toward the closing direction (toward the tube receiving portion 37) when the metal tube 11 is closed in order to more reliably hold the metal tube 11. 40.

  Further, it is preferable that a liner can be attached to the inner surface of the tube receiving portion 37 and the inner surface of the gripping claw 38, which are the contact surfaces to the metal tube, in the front clamp 36 (similar to the rear clamp 15). This liner is attached to the contact surface and is interposed between the inner surface of the tube receiving portion 37 and the metal tube when the metal tube is clamped, and between the inner surface of the gripping claw 38 and the metal tube. By attaching a plurality of such liners to the inner surface of the tube receiving portion 37 and the inner surface of the gripping claws 38 so that a plurality of such liners are stacked in the radial direction of the metal tube, metal tubes having various outer diameters can be processed. I can do it. It should be noted that the support liner 51 (the inner surfaces of the outer claws 52 and the inner claws 62) may be provided with a similar liner.

  As shown in FIGS. 1 to 2 and FIGS. 6 to 10, a support clamp 51 is provided at a position close to the rear side of the front clamp 36 (in FIG. 3, it is hidden behind the column portion 34 and the front clamp 36 and cannot be seen). . The support clamp 51 is fixed to the rear surface of the column portion 34 of the clamp arm 31, and an inner claw 62 that abuts on the inner peripheral side (compression side) surface of the metal tube 11 like the tube receiving portion 37 of the front clamp 36. Similar to the gripping claws 38 of the front clamp 36, an outer claw 52 that comes into contact with the outer peripheral side (tension side) surface of the metal tube 11 is provided.

  Here, an abutting surface 63 that is curved in an arc shape so as to fit on the compression side surface of the metal tube 11 is formed inside the inner claw 62, while a tension side of the metal tube 11 is formed inside the outer claw 52. A contact surface 53 curved in an arc shape is formed so as to fit the surface. Therefore, when the support clamp 51 is closed, the contact surface 63 of the inner claw 62 contacts the compression side surface of the metal tube 11 and the contact surface 53 of the outer claw 52 contacts the surface of the metal tube 11 on the tension side. Thus, the deformation of the metal tube 11 can be regulated by gripping the metal tube 11 between the inner claw 62 and the outer claw 52 (gripping).

  Further, both the inner claw 62 and the outer claw 52 are supported so as to be rotatable around a support shaft 54 provided at an upper position of the metal tube 11, and are opened and closed (rotated) by hydraulic cylinders 64 and 55, respectively. Is possible. Among these hydraulic cylinders 64, 55, the hydraulic cylinder 55 that opens and closes the outer claw 52 is provided so as to connect the side surface (outer side) of the outer claw 52 and the fixing plate 61 installed on the clamp arm 31. Yes, the outer claw 52 is opened and closed by operating to expand and contract between the side surfaces of the outer claw 52 and the fixing plate 61. Similarly, a hydraulic cylinder 64 that opens and closes the inner claw 62 is provided so as to connect the side surface (outside) of the inner claw 62 and the fixing plate 61, and between the side surface of the inner claw 62 and the fixing plate 61. The inner claw 62 is opened and closed by operating so as to expand and contract.

  Further, the support shaft 54 of the support clamp 51 (inner claw 62 and outer claw 52) is disposed above the support shaft 39 of the front clamp 36 (gripping claw 38) as shown by Δh in FIGS. It is. This prevents the support clamp 51 from interfering with the induction heating coil 12 and enables the induction heating coil 12 to be moved to the vicinity of the front clamp 36, and is bent from the position near the grip portion by the front clamp 36 ( This is because gradation gradation) can be performed.

  Specifically, as shown in FIG. 7, when the inner claw 62 and the outer claw 52 are opened, the support clamp 51 (the inner claw 62, the outer claw 52 and the support shaft 54) is interposed between the metal tube 11. A gap is formed. This gap allows the support clamp 51 to be installed on the rear surface of the clamp arm without interfering with the coil 12, and the coil 12 is moved to the vicinity of the front clamp 36 by using this gap. I can do it.

  On the other hand, as described above, gradation bending is divided into three periods: (1) beginning bending, (2) intermediate bending period (steady bending), and (3) bending end, and (1) beginning bending. Moves the induction heating coil 12 to a position as close as possible to the front clamp 36 and starts induction heating and propulsion of the metal tube 11.

  11 to 12 show this operation. As shown in FIG. 11, when starting the bending process, the coil 12 is moved forward to approach the clamp arm 31 (front clamp 36). At this time, the inner claw 62 and the outer claw 52 of the support clamp 51 are open as shown in FIGS. 7 and 11, and the coil 12 is moved to a position close to the clamp arm 31 as shown in FIG. I can do it. Then, power is supplied to the coil 12 at this position to start processing.

  At the start of processing, the metal tube 11 is pushed forward by the propulsion mechanism 14, and at this time, the coil 12 is moved backward at the same time. Then, the coil 12 is moved to the steady position (the position of the coil 12 shown in FIG. 12), the bending start period ends, and the steady bending starts. It should be noted that the propulsion speed of the metal tube 11 is gradually increased during the period of the start of bending from the start of machining to the start of steady bending, and the propulsion speed is made constant when entering the steady bending. When the bending is started and the bending angle reaches a predetermined angle (for example, 45 ° or 60 °), the support clamp 51 is closed and the outer claw 52 and the inner claw 62 are brought into contact with the surface of the metal tube 11. Then, the metal tube 11 may be supported by these claws 52 and 62 (particularly the outer claws 52) to prevent the neck from being bent. Further, although the processing may be performed while moving the coil 12 at the end of bending, the support clamp 51 rotates together with the clamp arm 31 at the end of bending and is away from the bending point P (see FIG. 2). The support clamp 51 does not interfere with the movement of the coil 12.

  The support clamp 51 will be described in more detail. In the neck break, the portion immediately behind the gripping portion by the clamp arm 31 (proximal portion on the base end side of the metal tube 11 along the tube axis of the metal tube 11) is propelled by the metal tube 11. It is generated by bending so as to be bent outward by a bending moment caused by force. On the other hand, in the apparatus of the present embodiment, the deformation can be prevented by gripping the portion with the support clamp 51.

  In addition, as a configuration accompanying the support clamp 51, the apparatus of the present embodiment includes a pressing stopper 56 and a crush prevention stopper 57. The pressing stopper 56 is composed of a hydraulic cylinder installed on the lower rod 33 of the clamp arm 31, and as shown in FIG. 6, the distal end portion of the outer claw 52 in the closed state is closed in the closing direction (the inner claw 62 or the column of the clamp arm). (Toward the portion 34) to prevent the outer claw 52 from rotating in the opening direction. Thus, by pressing the outer claw 52 with the pressing stopper 56 when the support clamp 51 is closed, it is possible to more reliably prevent the neck from being deformed.

  The pressing stopper 56 is disposed below the loading position of the metal tube 11. This is because the pressing stopper 56 does not get in the way when the metal tube 11 is taken out as indicated by an arrow E in FIG. For the same reason, the hydraulic cylinder 40 that presses the gripping claws 38 of the front clamp 36 in the closing direction is also arranged below the loading position of the metal tube 11 like the pressing stopper 56 (see FIG. 5). .

  On the other hand, the crush prevention stopper 57 is fixed to the column portion 34 of the clamp arm 31 so that the tip of the outer claw 52 abuts in the closed state, and the claw prevention stopper 57 prevents the outer claw 52 from rotating excessively in the closing direction. It is a deterrent. By providing this stopper 57, it is possible to eliminate the possibility that the outer claw 52 that requires a large support force against the neck deformation will be excessively rotated in the closing direction and an excessive force is applied to the metal tube 11 to deform it. I can do it.

  Further, as shown in FIGS. 8 to 9, the inner claw 62 has a width W1 smaller than the width W2 of the outer claw 52, and the front surface of the inner claw 62 and the front surface of the outer claw 52 are in the same position in the front-rear direction. However, the rear surface of the inner claw 62 is positioned in front of the rear surface of the outer claw 52. This is because the inner claw 62 can suppress deformation on the compression side, but the tube surface on the compression side may rise to the support shaft side depending on the thinning rate (the compression force is large) ( This is because it is possible to escape this (see FIG. 14 described later).

  For the same reason, as shown in FIG. 13, the inner surface of the inner claw 62 contacts the metal tube 11 so that the inner diameter of the contact surface increases toward the rear (that is, away from the surface of the metal tube 11). A taper surface (inclined surface) 63a may be formed. In this case, the width of the inner claw 62 may be made equal to the width of the outer claw 52 as shown in FIG. 13, or the width W1 of the inner claw 62 is made smaller than the width W2 of the outer claw 52 as described above. In addition, the tapered surface 63a may be formed.

  FIG. 14 shows a cross-sectional state of the metal tube in the vicinity of the support clamp. By forming the tapered surface 63a on the contact surface of the inner claw 62 with the metal tube 11, the bulge on the compression side is released. You can see how you can.

  Furthermore, in this embodiment, it is possible to automate the neck break prevention process by the support clamp. 4 to 7, the processing apparatus of the present embodiment can include an angle counter (angle sensor) 101 that measures the rotation angle of the clamp arm 31 on the support shaft 35 of the clamp arm 31. A count value (a rotation angle of the clamp arm) by the angle counter 101 is input to the processing control unit 102.

  The processing control unit 102 is a device for bending, that is, a propulsion drive unit (propulsion hydraulic cylinder) 16 that propels the metal tube 11 and a compression drive unit (compression hydraulic pressure) that applies a compressive force to the metal tube 11. Cylinder) 22, the drive unit of induction heating coil 12 (the moving mechanism for moving power supply and coil 12), the cooling mechanism for injecting cooling water 10 onto metal pipe 11, and the like. In addition, the opening and closing of the support clamp 51 is controlled.

  Specifically, the machining control unit 102 receives the angle detection signal output from the angle counter 101, compares the rotation angle of the clamp arm 31 with a preset value (set value), and determines the clamp arm 31. When the rotation angle reaches the set value, an operation signal for closing the support clamp 51 is output to the hydraulic cylinders 55 and 64 and the pressing stopper 56. The hydraulic cylinders 55 and 64 that have received this operation signal close the outer claws 52 and the inner claws 62, respectively, and bring the claws 52 and 62 into contact with the metal tube 11. The pressing stopper 56 locks the outer claw 52 in the closing direction. In addition, the above set value is an appropriate input means before starting processing according to the material, diameter, thickness, thickness reduction rate, etc. of the metal base tube (metal tube before bending) to be processed as described above (see FIG. (Not shown) may be input to the machining control unit 102.

  Further, when driving the support clamp 51 described above, it is not necessary to interrupt the processing (promotion of the metal tube 11), and it is not necessary to manually attach the attachment as in the prior art, and according to the apparatus of this embodiment. Stable quality control and good productivity can be realized by continuous processing, and if the metal pipe (metal pipe 11) is set in this equipment, the entire process until the bending process is completed can be automated. Is also possible.

  As mentioned above, although embodiment of this invention was described, this invention is not limited to these, It is clear to those skilled in the art that a various change can be made within the range as described in a claim. .

DESCRIPTION OF SYMBOLS 11 Metal pipe 12 Induction heating coil 13 Guide roller 14 Propulsion mechanism 15 Back clamp 16 Propulsion drive part (hydraulic cylinder)
21 Compression mechanism 22 Compression drive (hydraulic cylinder)
23 Chain 24 Sprocket 25 Device frame 26 Body frame 27 Columnar frame 31 Clamp arm 32 Arm rod (upper rod)
33 Arm rod (lower rod)
34 Supporting portion 35, 35a Support shaft 36 Front clamp 37 Tube receiving portion 38 Grip claw 39 Grip claw rotation support shaft 40 Grip claw pressing hydraulic cylinder 41 Grip claw opening / closing hydraulic cylinder 51 Neck fold prevention support clamp 52 Outer claw 53, 63 Contact surface to metal tube 54 Rotating support shaft of outer claw and inner claw 55 Hydraulic cylinder for opening and closing outer claw 56 Press stopper 57 Crush prevention stopper 61 Fixing plate 62 Inner claw 63a Tapered surface 64 Inner claw opening / closing hydraulic pressure Cylinder 101 Angle counter 102 Machining control part P Bending point (position of induction heating coil during steady bending)

Claims (18)

When the propulsion direction of the metal strip to be bent is the front and the direction opposite to the propulsion direction is the rear,
Heating means for heating a part of the metal strip in an annular shape;
Propulsion means for propelling the metal strip toward the heating means;
The metal strip is held in front of the heating portion by the heating means and supported by a support shaft so as to be pivotable. The metal strip is swung around the support shaft as the metal strip is propelled by the propulsion means. A metal strip bending apparatus comprising a clamp arm for applying a bending moment to a strip,
A support clamp that contacts the surface of the metal strip at a position close to the rear side of the grip portion by the clamp arm and prevents neck deformation of the metal strip;
The support clamp includes an outer claw that can be opened and closed between a closed state in contact with the bent outer peripheral surface of the metal strip and an open state spaced from the bent outer peripheral surface of the metal strip. Metal strip bending apparatus characterized by the above. The heating means is movable in the front-rear direction toward the clamp arm,
The outer claw is rotatable about a pivot shaft provided at a base end portion to enable the opening and closing operation, and in the opened state, the outer claw is between the support clamp and the metal strip. The bending of the metal strip according to claim 1, wherein a gap is formed between the outer claw and the rotation support shaft and the metal strip in the open state so as to accommodate the heating means. Processing equipment. While arranging the pivot of the outer claw above the loading position of the metal strip,
The metal strip bending apparatus according to claim 2, wherein the outer claws are installed so that the outer claws are positioned above the loading position of the metal strips in the open state. 4. The pressure stopper according to claim 1, further comprising: a pressing stopper that presses the tip of the outer claw in the closing direction to prevent the outer claw from rotating in the opening direction in the closed state. 5. Metal strip bending equipment. The metal strip bending apparatus according to claim 4, wherein the pressing stopper is disposed below a loading position of the metal strip. 6. The crush prevention stopper according to claim 1, further comprising a crush prevention stopper that prevents a distal end portion of the outer claw from abutting in the closed state and preventing the outer claw from excessively rotating in the closing direction. The apparatus for bending metal strips as described. A bending angle detecting means for detecting a turning angle of the clamp arm;
A control unit that compares the turning angle detected by the bending angle detection means with a predetermined value and sets the outer claw in a closed state when the turning angle becomes the predetermined value; Furthermore, the bending apparatus of the metal strip material as described in any one of Claim 1 to 6 further provided. The support clamp is
An inner claw capable of opening and closing between a closed state in contact with the surface on the inner circumferential side of the metal strip and an open state spaced from the surface on the inner circumferential side of the metal strip. The bending apparatus for a metal strip according to any one of 1 to 7. The heating means is movable in the front-rear direction toward the clamp arm,
The inner claw is rotatable about a pivot shaft provided at a base end portion to enable the opening / closing operation, and in the opened state, the inner claw is between the support clamp and the metal strip. It is installed so that a gap is formed between the inner claw and the rotation support shaft and the metal strip in the open state so as to accommodate the heating means,
The metal strip bending apparatus according to claim 8, wherein the heating means can be moved forward to a position close to the clamp arm at the start of machining. The inner nail is narrower in the front-rear direction than the outer nail,
The inner claw and the outer claw so that the front surface of the inner claw and the front surface of the outer claw are substantially in the same position in the front-rear direction, and the rear surface of the inner claw is positioned forward of the rear surface of the outer claw The metal strip bending apparatus according to claim 8 or 9. The taper surface which inclines so that it may move away from the said metal strip surface gradually as it goes back is formed in the inner surface of the said inner nail | claw which is a surface contact | abutted to the said metal strip member. Metal strip bending equipment. A bending angle detecting means for detecting a turning angle of the clamp arm;
A control section for comparing the turning angle detected by the bending angle detection means with a predetermined value and closing the inner claw when the turning angle reaches the predetermined value; The bending apparatus for a metal strip according to any one of claims 8 to 11, further comprising: Compression means for applying a compressive force to the metal strip by applying a pull back force to pull back the clamp arm in a direction opposite to the turning direction of the clamp arm accompanying the propulsion of the metal strip; The bending apparatus for metal strips according to any one of claims 1 to 12. A heating means for heating a part of the metal strip material to be bent in an annular shape, a propelling means for propelling the metal strip material toward the heating means, and a front side of the heating portion of the metal strip material by the heating means. A bending process comprising: a clamp arm that grips and is supported so as to be pivotable by a support shaft and pivots about the support shaft to apply a bending moment to the metal strip as the metal strip is propelled by the propulsion unit. A support clamp device for preventing neck breakage that can be attached to the device,
Between a closed state in contact with the surface on the bent outer peripheral side of the metal strip at an adjacent position behind the grip portion by the clamp arm and an open state spaced from the surface on the bent outer peripheral side of the metal strip. An outer claw capable of opening and closing;
And a fixing means for fixing the outer claw to the clamp arm. A closed state in which the metal strip is in contact with the surface on the inner side of the bending at a position close to the rear side of the grip portion by the clamp arm, and an open state in which the metal strip is spaced from the surface on the inner side of the bending. It is further equipped with an inner claw that can be opened and closed between
The support clamp device for preventing neck break according to claim 14, wherein the fixing means is further capable of fixing the inner claw to the clamp arm. A method for producing a metal strip having a bent portion, in which a part of the metal strip is heated in an annular shape, and a bending moment is applied to the heated portion to plastically deform at least a portion of the metal strip into a curved state. There,
While grasping the position in the vicinity of the heating portion of the metal strip and gripping the metal strip with a clamp arm that can be pivoted about a support shaft that is spaced a certain distance from the gripping portion,
While propelling the metal strip in the direction of the material axis, the gripping part by the clamp arm is turned and guided so that at least a part of the metal strip is curved in an arc,
When the propelling direction of the metal strip is the front and the direction opposite to the propelling direction is the rear, the metal strip is guided by the clamp arm and is behind the grip portion of the metal strip by the clamp arm. A bending portion characterized in that the metal strip is bent while preventing the neck from being deformed by bringing the support clamp into contact with at least the surface of the metal strip on the outer peripheral side in the proximity position on the side. A method for manufacturing metal strips. The support clamp includes an outer claw that can be opened and closed between a closed state in contact with the bent outer peripheral surface of the metal strip and an open state spaced from the bent outer peripheral surface of the metal strip. ,
The metal strip provided with the bent portion according to claim 16, wherein when the clamp arm turns at a predetermined angle, the outer claw is closed and brought into contact with a bending outer peripheral surface of the metal strip. Production method. The support clamp is an inner claw capable of opening and closing between a closed state in contact with the surface on the bending inner peripheral side of the metal strip and an open state spaced from the surface on the bending inner peripheral side of the metal strip. Further including
18. The metal strip provided with a curved portion according to claim 17, wherein when the clamp arm turns at a predetermined angle, the inner claw is brought into a closed state and brought into contact with a bending inner peripheral surface of the metal strip. Manufacturing method.

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