JP5784387B2 - Metal pipe bending machine - Google Patents

Description

  The present invention relates to a metal pipe bending apparatus, and more particularly to a technique for bending a metal pipe while preventing a reduction in pipe thickness.

  Today, metal pipes are widely used as pipes for transporting fluids such as oil, gas, and various liquids in industrial facilities such as plants, factories, and power plants, or as skeleton structures for buildings such as bridges and stadium roofs. These metal pipes are pipes that have been standardized and manufactured in advance to a predetermined shape (straight pipes, elbows, bends, etc.), while straight pipes are bent according to the construction object. (Hereinafter referred to as “bend pipe”) is widely used because it can flexibly cope with various curvatures and pipe shapes.

  On the other hand, when a bent pipe is manufactured, simply bending a straight pipe as a raw material may reduce the thickness of the outer peripheral side of the bent pipe portion and may not satisfy the strength required for the pipe. Therefore, a technique (so-called compression bending) is known which prevents such reduction (thinning) of the tube thickness by performing processing while applying a compressive force in the tube axis direction simultaneously with bending.

  FIG. 5 is a diagram schematically showing a bending apparatus related to such compression bending. As shown in this figure, the apparatus is a heating coil for heating a part of the metal tube 11 to be processed in an annular shape. 12, a propulsion means (propulsion cylinder 18) for propelling the metal tube in the tube axis direction B toward the heating coil 12, and a clamp arm 13 that holds the metal tube 11 and is rotatable about the support shaft 14. While holding the front portion of the heating portion of the metal tube 11 by the coil 12 with a clamp arm (hereinafter also referred to simply as “arm”) 13, the holding shaft 14 is moved along the progression of the metal tube 11 by the propulsion means 18. , And a bending moment is applied to the metal tube 11.

  At the same time, a compression force is applied to the metal tube 11 by applying a pullback force G, which is a force in the direction opposite to the propulsion direction B of the metal tube 11, to the clamp arm 13. For this reason, drive means (compression cylinder 41) is provided separately from the propulsion means 18, and this is connected to the tip of the clamp arm 13 by, for example, a wire. In FIG. 5, reference numeral 16 denotes a moving base that can move in the tube axis direction, and reference numeral 17 denotes a rear clamp that is mounted on the moving base 16 and holds the rear part of the metal tube 11.

  Moreover, there exists the following patent document 1 as a proposal relevant to such compression bending.

JP 2009-12062 A

  By the way, in the conventional compression bending, a hydraulic cylinder is usually used as a driving means for applying a compressive force to a metal tube, like a driving means for propulsion.

  However, when a hydraulic cylinder is used as the driving means for compression, the cylinder for compression only requires a stroke corresponding to the bending radius even if the metal tube is bent at 90 °, whereas the cylinder for compression is A long stroke corresponding to the distance along the circumference of the bent tube portion is required following the metal tube bent in an arc shape. In particular, since the stroke becomes longer as the bending angle and the bending radius become larger, a general-purpose (and therefore inexpensive) hydraulic cylinder cannot be used as a compression cylinder when forming a processing apparatus, and a specially manufactured length. In the past, it has often been necessary to use a cylinder dedicated to the stroke. For this reason, there is a problem that it takes a long time to manufacture the processing apparatus (the delivery time becomes long) and the manufacturing cost increases.

  In the apparatus shown in FIG. 5, as the bending process proceeds as shown in FIG. 6, the angle formed by the clamp arm 13 and the wire connecting the compression cylinder 41 and the clamp arm 13 changes. The relationship between the output of the compression cylinder 41 (tensile force G by the cylinder) and the compression force actually applied to the metal tube 11 is not constant. For this reason, in order to make the compression force applied to the metal tube 11 constant, it is necessary to change the output of the compression cylinder 41 as the bending process proceeds, and the control of the compression cylinder 41 must be complicated.

  On the other hand, in order to avoid the above inconvenience, it is also conceivable to apply a retracting force at a position near the support shaft 14 of the clamp arm 13.

  For example, as shown in FIG. 7, a pinion 42 that rotates together with the clamp arm 13 is fixed to a support shaft portion of the arm 13, and a hydraulic cylinder 41 passes through a rack 43 that meshes with the pinion 42, so that the rotation of the arm 13 is reversed. If a rotational force (G) is applied, a compressive force can be generated in the metal tube 11. Further, as shown in FIG. 8, a sprocket 44 that rotates together with the clamp arm 13 is attached to the support shaft portion of the arm 13 and is reversely rotated by the hydraulic cylinder 41 via the chain 45 in the same manner as in the method of FIG. Directional rotational force (G) may be applied.

  However, in the apparatus shown in FIGS. 7 and 8, when a large compressive force is required, as can be seen from the method of FIG. 5 in which a pulling force can be applied to the tip of the clamp arm. For example, in order to be able to cope with a severe thinning rate close to zero, it is difficult to use a compression cylinder 41 having a very large output.

  Therefore, an object of the present invention is to make it possible to efficiently apply a large compressive force to a metal tube with a small output and a compact drive source without complicating the compression control.

  In order to solve the above-mentioned problems and achieve the object, a metal pipe bending apparatus according to the present invention comprises a heating means for annularly heating a part of a metal pipe to be bent, and the metal pipe toward the heating means. Including a propulsion means for propelling the metal pipe in the direction of the tube axis and a clamp arm that grips the metal tube and is rotatable about the support shaft, and grips a front portion of the heating portion of the metal tube by the heating means. At the same time, the gripping point is swung around the support shaft as the metal pipe is propelled by the propulsion means, and thereby a bending means is applied to the metal pipe, and the gripping point is rotated as the metal pipe is propelled by the propulsion means. Compression means for applying a compressive force to the metal pipe by applying a pulling force for pulling back the moving clamp arm to the clamp arm with the support shaft as a fulcrum. An apparatus for bending a metal tube, wherein the compression means includes a connection member connected to a position outside the gripping point of the metal tube as viewed from the support shaft side of the clamp arm, and the connection member via the connection member. And a motor for applying the retracting force to the outer position of the clamp arm.

  In the bending apparatus of the present invention, the metal pipe is propelled while the metal pipe is heated annularly by the heating means, and at the same time, the metal pipe that has passed through the heating means is curved in an arc by the guide means. To guide.

  Specifically, when the propulsion direction of the metal tube is “front” (in this application, the front side is described as “front” in the direction of metal tube propulsion, and the reverse direction is “rear”), The front part of the heating part is gripped by the clamp arm. The clamp arm is installed so as to be rotatable about a support shaft, and rotates as the metal tube is propelled by the propulsion means. Further, as the arm rotates, the gripping part pivots about the support shaft, and a bending moment is applied to the heating portion of the metal tube, so that the metal tube is continuously plastically deformed to draw an arc. You can bend the metal tube. The rear portion of the metal tube is gripped by, for example, a rear clamp provided on a moving base that can be advanced toward the heating means, and the propelling means pushes the metal tube toward the heating means through the moving base. It ’s fine.

  On the other hand, by applying a compressive force in the direction of the pipe axis in addition to the bending moment, thinning of the pipe outer peripheral side (thickness reduction) is prevented. This compressive force is applied to the clamp arm by pulling back the clamp arm that rotates as the metal pipe is propelled by the propulsion means, in other words, the rotation direction of the clamp arm. It is generated by applying a reverse force to the clamp arm.

  The compression means includes a connecting member connected to the clamp arm and a motor that applies the pullback force to the clamp arm via the connecting member. In the present invention, by using a motor instead of a cylinder as a driving means for applying a compressive force in this way, the above-described cylinder stroke problem (a long stroke cylinder is required) can be solved. Further, the connecting member is connected to a position outside the gripping point of the metal tube as viewed from the support shaft side of the clamp arm. This is because the metal tube can be efficiently applied to the metal tube with the support shaft as a fulcrum (a large compression force with a small pulling force).

  As a preferred embodiment, the connecting member is a chain, and further includes a chain guide that guides the chain in a circular arc shape along the turning path of the clamp arm.

  The “motor” typically uses a hydraulic motor. However, the “motor” of the present invention is not limited to a hydraulic motor, and the present invention does not exclude the use of other driving means for generating rotational power such as an electric motor.

  In one aspect of the present invention, in the above processing apparatus, a first sprocket that meshes with the chain is disposed on one end side of the swiveling track at the tip of the clamp arm, and the other end of the swiveling track at the tip of the clamp arm. A second sprocket that meshes with the chain is disposed on the side, the chain is looped between the first sprocket and the second sprocket, and extends parallel to each other between the first sprocket and the second sprocket. The clamp arm is connected to one of the two existing chain parts, and the motor is connected to the first sprocket or the second sprocket, whereby the retracting force is applied by the motor via the chain part. Can be added to the clamp arm.

  Further, in another aspect of the present invention, one end of the chain is fixed to one end of the swivel track of the tip of the clamp arm, and the other end of the chain is fixed to the tip of the clamp arm. A sprocket that is fixed to the other end of the swivel track and meshes with the chain and rotates as the clamp arm swivels is provided at the tip of the clamp arm so that the sprocket rotates as the clamp arm swivels. The motor is provided at the tip of the clamp arm so that a counteracting rotational force can be applied to the sprocket, thereby enabling the pullback force to be applied to the clamp arm.

  Further, in the present invention, it is preferable that the support shaft extends in the vertical direction, and the clamp arm pivots horizontally as the metal tube is propelled to guide the metal tube. Further, a gear may be appropriately interposed between the output shaft of the motor and the sprocket. By adjusting (increasing) this gear ratio, a large compression force can be applied to the metal pipe even with a small output motor. Become.

  In addition, the dimension (outer diameter / inner diameter / thickness dimension) of the metal tube to be processed in the present invention is not particularly limited. As for the material of the metal pipe, 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 other metal materials are mainly used. It may be intended for pipes made of other metal alloys.

  The metal pipe bending apparatus according to the present invention can efficiently apply a large compressive force to a metal pipe with a small output and a compact drive source without complicating compression control.

  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 schematically showing a metal tube bending apparatus according to the first embodiment of the present invention. FIG. 2 is a plan view schematically showing a state during processing by the bending apparatus according to the first embodiment. FIG. 3 is a plan view schematically showing a metal pipe bending apparatus according to the second embodiment of the present invention. FIG. 4 is a plan view schematically showing a state during processing by the bending apparatus according to the second embodiment. FIG. 5 is a plan view schematically showing a bending apparatus according to the first comparative example of the present invention. FIG. 6 is a diagram illustrating the operation of the bending apparatus according to the first comparative example. FIG. 7 is a plan view schematically showing a bending apparatus according to a second comparative example of the present invention. FIG. 8 is a plan view schematically showing a bending apparatus according to a third comparative example of the present invention.

[First Embodiment]
As shown in FIGS. 1 to 2, the metal tube bending apparatus according to the first embodiment of the present invention includes a heating coil 12 that annularly heats a metal tube 11 that is a processing target, and a front portion of the heating coil 12. A clamp arm 13 having a clamp portion 15 for gripping the metal tube 11 at a position and supported so as to be rotatable around a support shaft 14 and a clamp portion (rear clamp) 17 for gripping the rear portion of the metal tube 11 and metal A moving base 16 that can move in the length direction of the tube 11 (left-right direction in FIG. 1) and a propulsion cylinder (propulsion means) 18 that pushes the moving base 16 toward the clamp arm 13 (heating coil 12) are provided.

  The moving base 16 can be constituted by a carriage provided with wheels so that it can travel toward the arm 13 as the metal tube 11 is propelled, for example. Further, in this case, the propulsion cylinder 18 that gives propulsive force to the metal pipe 11 may be installed on the main body frame (not shown) of the apparatus to push the moving base 16, but is mounted on the moving base 16. In this case, the propulsion cylinder 18 is engaged with the moving base 16 and the main body frame to advance the moving base 16 so as to draw the moving base 16 toward the arm 13, and is thereby gripped by the rear clamp 17. The metal tube 11 is pushed forward toward the heating coil 12. In the figure, the movement of the moving base 16 is indicated by an arrow A, and the propulsion of the metal tube 11 is indicated by an arrow B.

  In addition, this processing apparatus uses a rotational force generated by the hydraulic motor 21 that is looped between the hydraulic motor 21 and the two sprockets 22 and 23 as compression means for applying a compression force to the metal tube 11. A roller chain (connecting member) 24 that transmits the pulling force F to the clamp arm 13 and chain guides 25 and 26 that support the roller chain 24 (hereinafter sometimes simply referred to as “chain”) in an arc shape are provided.

  As described above, the clamp arm 13 rotates around the support shaft 14 as the metal tube 11 is propelled, and therefore the tip of the clamp arm 13 rotates around the support shaft 14 while drawing an arcuate track. The sprockets 22 and 23 that support the chain 24 are arranged on one end side of the arcuate orbit at the tip of the arm (the arm 13 has not yet rotated and is substantially orthogonal to the metal tube 11 (the processing shown in FIG. 1). The first sprocket 22 disposed in the vicinity of the arm tip in the initial state before the start) and the other end of the swivel track of the arm tip (the clamp arm 13 is completely (in this example, approximately 110 °). 2) a second sprocket 23 arranged at a position near the tip of the arm in the rotated state.

  The chain guides 25 and 26 are composed of two guide plates having a planar shape with an arc having a central angle of about 110 °, for example, corresponding to the rotation range of the arm 13. The inner guide plates (referred to as “inner guide plates”) 25 extend so as to form arcs parallel to each other as seen from the plane so as to follow the turning trajectory of the front end portion, and the first sprocket 22 and the second sprocket 23. A guide plate (referred to as “outer guide plate”) 26 arranged on the outer side of the inner chain portion of the roller chain 24 that is looped between the outer chain portion and the outer chain portion of the chain 24 in an arc shape and Support to be able to run. The guide plates 25 and 26 are positioned below the arm 13 and supported (installed) on the floor so as not to obstruct the rotation of the clamp arm 13.

  The tip of the arm 13 is connected (fixed) to one (inner chain portion) of two chain portions extending in parallel between the first and second sprockets 22 and 23. This fixed state is indicated by a black circle (reference numeral 27) in FIGS. Therefore, as shown in FIG. 2, when the arm 13 is rotated by the propulsion of the metal tube 11, the chain 24 travels between the sprockets 22 and 23 while being in contact with the guide plates 25 and 26.

  Further, as the chain 24 travels, the second sprocket 23 rotates. On the other hand, a hydraulic motor 21 is connected to the first sprocket 22, and a rotational force E in a direction opposite to the rotation of the first sprocket 22 accompanying the rotation C (chain travel D) of the arm 13 is applied to the hydraulic motor. 21 can be applied to the first sprocket 22. Therefore, the pulling back force F can be applied to the clamp arm 13 through the inner chain portion by driving the hydraulic motor 21.

  Since the inner chain portion is connected to the arm tip outside the clamp portion 15 when viewed from the support shaft 14, the compression is efficiently performed with the support shaft 14 as a fulcrum (large with a small retracting force F). A force can be applied to the metal tube 11. Further, a gear (not shown) may be interposed between the hydraulic motor 21 and the first sprocket 22, and by setting this gear ratio large, for example, when the required thinning rate is close to zero. It is possible to cope with a case where a large compressive force is required.

  Further, in the apparatus described in Patent Document 1, a compression cylinder is mounted on the moving base, and the compression cylinder moves together with the moving base. Therefore, in controlling the compression force (retraction force), the movement base ( It is necessary to consider both the movement of the compression cylinder) and the rotation of the clamp arm. On the other hand, in the present embodiment (the same applies to the second embodiment described below), it is only necessary to consider the rotation of the clamp arm. Since the control can be performed independently, there is an advantage that the compression control can be simplified.

[Second Embodiment]
Next, a metal pipe bending apparatus according to the second embodiment of the present invention will be described with reference to FIG. 3. The same reference numerals are given to the same components as those in the apparatus of the first embodiment. The duplicate explanation is omitted and the differences are mainly described.

  As shown in FIG. 3, the bending apparatus according to the second embodiment of the present invention is similar to the apparatus according to the first embodiment in that a metal tube is obtained by applying a retracting force F to the clamp arm 13 by the hydraulic motor 21. 11, a compression force is applied to the arm 11, and a hydraulic motor 21 and a compression driving sprocket 22 connected to the hydraulic motor 21 are mounted on the distal end portion of the arm 13.

  More specifically, the hydraulic motor 21 and a plurality of sprockets 22, 31, 32 that mesh with the roller chain 34 are attached to the tip of the clamp arm 13. As in the first embodiment, the roller chain 34 is supported by the chain guide 35 so as to draw an arc along the turning trajectory of the arm tip, so that one end side and the other end side of the turning trajectory at the arm tip end are provided. However, unlike the first embodiment in which the two sprockets are looped between the two sprockets and run as the arm rotates, one end is located on one end side of the swivel track of the arm tip, and The other end is fixed to the other end side of the orbit of the arm tip. As described above, in the present embodiment, the chain 34 is stretched in a single state rather than in the form of a ring. Therefore, the chain guide 35 is a single piece having an arcuate planar shape along the turning trajectory of the arm tip. A guide plate may be provided.

  The sprocket mounted on the tip of the arm is composed of a drive sprocket 22 to which the drive shaft of the hydraulic motor 21 is connected, and two driven sprockets installed before and after the drive sprocket 22 so that the chain 34 meanders between the sprockets. 31 and 32. The driven sprockets 31 and 32 are meshed with the chain 34 and freely rotate (freely receiving the rotation of the arm 13), but are arranged closer to the support shaft 14 than the drive sprocket 22. As a result, the chain 34 is attracted toward the support shaft by the driven sprockets 31 and 32 before and after the drive sprocket 22, and the chain 34 can be reliably engaged with the drive sprocket 22.

  As shown in FIG. 4, the sprockets 22, 31, 32 that mesh with the chain 34 rotate as the arm 13 rotates. At this time, the hydraulic motor 21 connected to the drive sprocket 22 is driven to rotate the sprocket 21. It is possible to apply a rotational force E in the opposite direction (rotational force against the rotation of the sprocket 22 accompanying the rotation of the arm 13), thereby applying a pullback force F to the clamp arm 13, A compressive force can be applied.

  As described above, according to the processing apparatus according to the embodiment of the present invention, the pulling force F is applied to the clamp arm 13 by the hydraulic motor 21, and the compressive force is applied to the metal tube 11 during the bending process. Thinning can be suppressed. The present invention is not limited to these embodiments, and it will be apparent to those skilled in the art that various modifications can be made within the scope of the claims.

A Direction of movement of moving base B Direction of propulsion of metal tube C Direction of rotation of clamp arm D Direction of travel of chain accompanying rotation of clamp arm E Rotational force by compression means (hydraulic motor) F Pullback force of arm G For compression Pull-back force by hydraulic cylinder 11 Metal tube 12 Heating coil 13 Clamp arm 14 Support shaft 15 Clamp part 16 Moving base 17 Rear clamp 18 Propulsion cylinder 21 Compression hydraulic motor 22 Compression drive sprocket 23, 31, 32 Drive sprocket 24, 34 , 45 Roller chain 25 Chain guide (inner guide plate)
26 Chain guide (outer guide plate)
27 Clamp Arm / Roller Chain Connection 41 Hydraulic Cylinder for Compression 42 Pinion 43 Rack 45 Sprocket

Claims (4)

A heating means for heating a part of the metal pipe to be bent in an annular shape;
Propulsion means for propelling the metal tube in the tube axis direction toward the heating means;
A clamp arm that grips the metal tube and is rotatable about a support shaft. The clamp arm grips a front portion of a heating portion of the metal tube by the heating unit, and the grip point is a metal by the propulsion unit. Guide means for turning about the support shaft as the tube is propelled, thereby applying a bending moment to the metal tube;
Compression means for applying a compressive force to the metal pipe by applying a pullback force for pulling back the clamp arm that rotates as the metal pipe is propelled by the propulsion means to the clamp arm with the support shaft as a fulcrum;
A metal pipe bending apparatus comprising:
The compression means includes
A connecting member connected to a position outside the gripping point of the metal tube as viewed from the support shaft side of the clamp arm;
Via the coupling member viewed contains a motor which applies the pulling back force to the outside position of the clamp arm,
The connecting member is a chain;
The bending apparatus for the metal pipe further includes a chain guide for guiding the chain in an arc shape so as to follow the turning trajectory of the clamp arm,
A first sprocket that meshes with the chain is disposed on one end side of the swivel track at the tip of the clamp arm,
A second sprocket that meshes with the chain is disposed on the other end side of the orbit of the tip of the clamp arm,
The chain is looped between the first sprocket and the second sprocket,
Connecting the clamp arm to one of two chain portions extending parallel to each other between the first sprocket and the second sprocket;
Connecting the motor to the first sprocket or the second sprocket,
Accordingly, the pulling force can be applied to the clamp arm by the motor through the chain portion . A heating means for heating a part of the metal pipe to be bent in an annular shape;
Propulsion means for propelling the metal tube in the tube axis direction toward the heating means;
A clamp arm that grips the metal tube and is rotatable about a support shaft. The clamp arm grips a front portion of a heating portion of the metal tube by the heating unit, and the grip point is a metal by the propulsion unit. Guide means for turning about the support shaft as the tube is propelled, thereby applying a bending moment to the metal tube;
Compression means for applying a compressive force to the metal pipe by applying a pullback force for pulling back the clamp arm that rotates as the metal pipe is propelled by the propulsion means to the clamp arm with the support shaft as a fulcrum;
A metal pipe bending apparatus comprising:
The compression means includes
A connecting member connected to a position outside the gripping point of the metal tube as viewed from the support shaft side of the clamp arm;
Via the coupling member viewed contains a motor which applies the pulling back force to the outside position of the clamp arm,
The connecting member is a chain;
The bending apparatus for the metal pipe further includes a chain guide for guiding the chain in an arc shape so as to follow the turning trajectory of the clamp arm,
While fixing one end of the chain to one end of the swivel track at the tip of the clamp arm,
Fixing the other end of the chain to the other end of the swivel track at the tip of the clamp arm;
A sprocket that meshes with the chain and rotates as the clamp arm pivots is provided at the tip of the clamp arm,
The motor is provided at the tip of the clamp arm so that a rotational force against the rotation of the sprocket accompanying the turning of the clamp arm can be applied to the sprocket,
Thereby, it is possible to apply the pull-back force to the clamp arm . The motor, the bending apparatus for metal tubes according to claim 1 or 2 is a hydraulic motor. The support shaft extends in a vertical direction,
The metal tube bending apparatus according to any one of claims 1 to 3 , wherein the clamp arm pivots horizontally as the metal tube is propelled to guide the metal tube.

Images