JP5784378B2 - 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, various proposals regarding so-called compression bending have been made to prevent such thinning (reduction in tube thickness) by performing bending while applying a compressive force in the direction of the tube axis in addition to simply bending a straight tube. (For example, see Patent Documents 1 to 3 below).

JP-A-54-8154 JP 54-1112769 A JP 2009-12062 A

  By the way, while bending has the advantage of being able to flexibly adapt to the desired curvature and pipe shape as described above, when viewed from the processing company side, there are various processing requirements depending on the limited number of processing devices. It means that you have to respond. For example, when discussing the thinning rate, there are cases where a strict thinning rate close to zero is required, and in order to manufacture a highly accurate bent tube, the compressive force applied to the metal tube must be accurately set. Need to control.

  On the other hand, when manufacturing bent pipes, pipes with different diameters or pipes with different specified thinning rates are often processed one after another with a single processing device, which is a material from the viewpoint of productivity. It is also necessary to efficiently perform the work from the setting of the straight pipe to the removal of the pipe after completion of processing.

  However, a bending apparatus that can handle a wide range of thinning rates and various types of pipes with high accuracy and that has good workability has not been provided.

  Accordingly, an object of the present invention is to obtain a new bending apparatus that can cope with a wide range of required compressive force (particularly the thinning rate) with high accuracy and at the same time has good workability.

  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, whereby a guide means for applying a bending moment to the metal pipe, and a rear portion of the metal pipe is gripped to hold the metal pipe. A moving base having a rear clamp for transmitting a propulsive force to the tube and capable of traveling toward the heating means, and a retracting force that is a force in a direction opposite to the propelling direction of the metal tube by the propelling means A metal pipe bending apparatus comprising: a compression means for applying a compressive force to the metal pipe by applying it to the metal pipe via the clamp arm with the support shaft as a fulcrum. A compression drive means; a second compression drive means having a smaller output than the first compression drive means; and a compression control section for controlling the first compression drive means and the second compression drive means. The pull back force can be applied to the metal tube by using either one or both of the first compression driving means and the second compression driving means.

  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. This clamp arm (hereinafter sometimes simply referred to as “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 a rear clamp provided on a moving base that can proceed toward the heating means, and the propulsion means pushes the metal tube toward the heating means through the moving base.

  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 generated by applying a pull-back force, which is a force in the direction opposite to the propelling direction of the tube, by the compressing means to the metal tube via the clamp arm with the support shaft as a fulcrum. The compression means includes a first compression drive means having a large output and a second compression drive means having a small output, and the compression control unit controls the first compression drive means and the second compression drive means, Either or both of the compression drive means and the second compression drive means are used to apply the pullback force to the metal tube.

  In the present invention, the first compression drive means and the second compression drive means having different outputs as described above are selectively used so that the required thickness reduction rate, the pipe diameter / thickness dimension of the object to be processed, etc. This is because different compression drive means are used according to (that is, necessary compression force), and a more accurate compression force is applied to the metal tube.

  For example, when the required thinning rate is small and a large compression force is required, the first compression drive means having a large output is used (or both the first compression drive means and the second compression drive means are used). Bending may be performed. The first compression drive means and the second compression drive means use a hydraulic cylinder as a typical mode as will be described later. However, the first compression drive means and the second compression drive means include an actuator such as a hydraulic cylinder. In the same manner, generally, there is a characteristic that accuracy is lowered in an output region very small with respect to the rating (maximum output) (for example, linearity is lost and it is difficult to obtain an accurate output). Therefore, when only a small compression force is required, for example, when a strict thickness reduction ratio is not required, a more accurate compression force can be applied by using a small output compression drive means than a high output compression drive means. Is preferable. From this point of view, in the present invention, in addition to the first drive means having a large output, a second compression drive means having a small output is provided. When a small compression force is required, the second compression drive means compresses the metal tube. It was possible to apply power.

  As a typical example, both the first compression driving means and the second compression driving means are constituted by hydraulic cylinders. That is, a first hydraulic cylinder is provided as the first compression drive means, and a second hydraulic cylinder is provided as the second compression drive means. In this case, the compression control unit also includes two proportional relief valves having different settable maximum pressures, that is, a first proportional relief valve having a large settable maximum pressure and a settable maximum pressure being the first proportional relief valve. A second proportional relief valve smaller than the valve, and actuates either one or both of the first hydraulic cylinder and the second hydraulic cylinder via one of the first proportional relief valve and the second proportional relief valve. Oil is supplied to apply the pulling force to the metal tube.

  This is due to the same reason that the two large and small hydraulic cylinders are provided, and the proportional relief valve also generally has a higher pressure side (pressure value close to the maximum pressure) than the lower pressure side of the settable pressure range. This is because the accuracy of the set pressure is high. Therefore, in one aspect of the present invention, the first proportional relief valve having a large maximum pressure is used when two large and small proportional relief valves having different maximum pressures are required. In some cases, the use of a second proportional relief valve having a small maximum pressure makes it possible to apply a more accurate compressive force.

  Further, when hydraulic cylinders are used as the first compression driving means and the second compression driving means, the compression control unit constitutes a hydraulic circuit that supplies hydraulic oil to these hydraulic cylinders. In the hydraulic circuit, in addition to the first and second proportional relief valves, a hydraulic pump, an oil tank, and a relief valve to be used are switched between the first proportional relief valve and the second proportional relief valve. A switching valve and a switching valve for selecting a cylinder to be used are included.

  In the apparatus of the present invention, 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, and when viewed from a plane, the metal tube The support shaft and the second compression drive means are disposed on one side of the metal tube, and the first compression drive means is disposed on the other side of the metal tube and below the metal tube when viewed from above. It is preferable to arrange. In such a device, more preferably, a first guide wheel and a second guide wheel that are fixed to the clamp arm and rotate together with the clamp arm, and the force output from the first hydraulic cylinder is the first guide wheel. The compression means includes a first connecting member that transmits to the wheel and a second connecting member that transmits the force output from the second hydraulic cylinder to the second guide wheel.

  To remove the metal tube from the device after bending, it is usually done by hanging a wire rope around the metal tube, but as described above, on the other side (on the opposite side of the support shaft with the metal tube in between) If the first compression drive means to be arranged is installed below the metal tube, the first compression drive means, the first guide wheel, and the first connecting member can be prevented from interfering with the metal tube take-out operation. It is. This point will be further described later with reference to FIG.

  Further, according to the arrangement configuration of the first compression driving means (and the first guide wheel and the first connecting member), the first compression driving means does not interfere with the work for taking out the metal tube. The diameter of the ring can be increased (for example, the diameter of the first guide wheel can be made larger than the distance between the gripping point of the metal tube by the clamp arm and the support shaft), and thereby a larger compressive force can be obtained by the first compression driving means. Can be added to the metal tube to reduce the amount of thinning during bending.

  Similarly, from the viewpoint of facilitating the removal of the metal tube, the propulsion means is arranged on the one side (the same side as the support shaft with the metal tube sandwiched when viewed from above), that is, closer to the support shaft than the metal tube. It is preferable to do.

  Furthermore, in the apparatus of the present invention, the clamp arm includes a clamp portion that holds the metal tube in the middle portion in the vertical direction, and the clamp arm can be rotated by the support shaft at positions above and below the clamp portion. It is preferable that the first guide wheel is fixed at a lower position than the clamp portion, and the second guide wheel is fixed at an upper position than the clamp portion.

  The clamp arm that grips the front part of the metal tube and applies a bending moment to the metal tube receives the propulsive force from the propulsion means during processing. This propulsive force depends on the diameter of the tube, the wall thickness, the material, etc. It can be several hundred tons. On the other hand, there are movable parts such as bearings between the clamp arm and the apparatus main body to which the clamp arm is fixed, and the arm itself is also bent. A phenomenon occurs in which the clamp arm tilts when it is piled up and receives a propulsive force (hereinafter referred to as “falling” of the arm).

  This falling of the arm causes a processing error and hinders high-precision bending. On the other hand, it is conceivable to perform setup (setting of the processing equipment) that pre-weaves the fall of such an arm, but in actual work, it is rare to process various pipes with different pipe diameters one after another. However, changing the setting of the apparatus every time the pipe to be processed is replaced or whenever the specified thickness reduction rate changes is cumbersome and reduces productivity.

  Therefore, in the present invention, as a preferred embodiment, the clamp arm is supported by the support shaft above and below the clamp portion that holds the metal tube as described above, and the second guide wheel is fixed to the upper position. The second guide wheel receives the compression force (retraction force) by the second compression drive means, and if the second compression drive means is used, the retraction force in the direction opposite to the propulsion force is applied to the arm. Can be applied to the upper portion of the metal tube, and at the same time as applying a compressive force to the metal tube, the arm is raised (see arrow E in FIG. 2 described later), and the fall of the arm can be prevented or reduced.

  The diameter of the second guide wheel is smaller than the distance from the support shaft to the metal tube, and the second guide wheel and the second connecting member are on one side (the side closer to the support shaft than the metal tube). It is preferable to dispose the metal tube so that it does not obstruct the work of taking out the metal tube.

  According to the metal pipe bending apparatus according to the present invention, it is possible to cope with a wide range of thinning rates with high accuracy and good workability.

  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 an embodiment of the present invention. FIG. 2 is a front view schematically showing the bending apparatus according to the embodiment. FIG. 3 is a right side view schematically showing the bending apparatus according to the embodiment. FIG. 4 is a plan view showing a state after the metal tube is processed (an extraction state) in the bending apparatus according to the embodiment. FIG. 5 is a block diagram showing a compression hydraulic circuit provided in the bending apparatus of the embodiment.

  As shown in FIGS. 1 to 5, a metal pipe bending apparatus according to an embodiment of the present invention includes a main body frame 11 installed on a floor, and a heating coil 20 that annularly heats a metal pipe 10 to be processed. The clamp arm 21 rotatably attached to the main body frame 11, the carriage (moving base) 16 movable in the length direction of the main body frame 11 (left and right direction in FIGS. 1 and 2), and the carriage 16 are clamped Thrust cylinders (propulsion drive means) 31 and 31a to be advanced toward the arm 21, two compression cylinders (compression drive means) 41 and 51 for applying a compression force to the metal tube 10, and a clamp arm 21 fixed together therewith Two guide wheels (first guide wheel 42 and second guide wheel 52) that rotate about the support shafts 23, 24 and pullback forces D, E of the compression cylinders 41, 51 are used as the guide wheels 42, 52. In Chain that respectively transmit and a (coupling member) 43, 53.

  The compression cylinders 41 and 51 are composed of a parent cylinder (first compression drive means) 41 having a large output (maximum output) and a child cylinder (second compression drive means) 51 having a smaller output (maximum output). Become.

  The main body frame 11 includes a bottom plate portion 12 that serves as a base of the processing apparatus, and an arch portion 13 that rises vertically from the bottom plate portion 12 and supports the upper end portion of the clamp arm 21. The bottom plate portion 12 is installed on the floor, and a carriage 16 is placed on the upper surface of the bottom plate portion 12 via wheels 19 and rails (not shown). On the other hand, the arch portion 13 is stretched between two strut portions 14 that vertically rise from the left and right side edges of the bottom plate portion 12 and extend to a position above the metal tube, and the upper ends of the strut portions 14. And a beam portion 15.

  The metal pipe 10 (the chain 43 connecting the parent cylinder 41 and the first guide wheel 42 described later, and the chain 53 connecting the child cylinder 51 and the second guide wheel 52) also passes through the arch portion 13. 1 to extend in the length direction of the main body frame 11 (so as to pass between both support columns 14 and under the beam portion 15). In order to show these, FIG. . Also, in FIG. 2, in order to clearly show the metal tube 10 and the chains 43 and 53, one of the support columns 14 (the front side in FIG. 2) is not shown, and a part of the carriage 16 described later (in FIG. 2). The front side is cut away.

  The clamp arm 21 has a clamp portion 22 that holds the metal tube 10 at a position in front of the heating coil 20 at the center in the vertical direction. Further, the clamp arm 21 supports the upper end of the clamp arm 21 on the arch portion 13 (beam portion 15) of the main body frame 11 via a support shaft 23 and supports the lower end of the clamp arm 21 on the bottom plate portion 12 of the main body frame 11. A shaft 24 is rotatably supported. Each of the support shafts 23 and 24 is attached to the main body frame 11 so as to extend in the vertical direction. Therefore, the clamp arm 21 is swung horizontally (in a horizontal plane).

  A first guide wheel 42 that rotates together with the clamp arm 21 about the support shaft 24 is attached to the lower end portion of the clamp arm 21. The first guide wheel 42 meshes with the chain 43 and transmits the pulling back force D by the parent cylinder 41 to the clamp arm 21. The parent cylinder 41 is attached to the carriage 16, and the pulling force D (promotion of the metal tube 10) of the parent cylinder 41 is established by connecting the piston rod of the parent cylinder 41 and the first guide wheel 42 with the chain 43. The force in the direction opposite to the direction A) can be applied to the first guide wheel 42.

  The output of the parent cylinder 41 is greater than that of the child cylinder 51, and the radius R 1 of the first guide wheel 42 is greater than the distance R 3 between the grip position G of the metal tube 10 by the clamp portion 22 and the support shafts 23, 24. Therefore, if the parent cylinder 41 is used, a large compressive force (retraction force D) can be efficiently applied to the metal pipe 10 via the first guide wheel 42.

  Further, since the first guide wheel 42, the chain 43, and the parent cylinder 41 are disposed below the metal pipe 10, for example, as shown in FIG. When the metal tube 10 is pulled out in the propulsion direction as shown by a two-dot chain line, and the metal tube 10 is lifted by a crane (hook 62) and taken out from the processing apparatus, the work is performed without being disturbed by the first guide wheel 42 or the chain 43. Can be done.

  A second guide wheel 52 that rotates together with the clamp arm 21 around the support shaft 23 is attached to the upper end portion of the clamp arm 21 (the outer peripheral portion of the boss of the support shaft 23). The second guide wheel 52 meshes with the chain 53 and transmits the retracting force E generated by the child cylinder 51 to the clamp arm 21. A child cylinder 51 that is one of the compression cylinders is attached to the arch portion 13 of the main body frame 11, and the piston rod of the child cylinder 51 and the second guide wheel 52 are connected by the chain 53, thereby the child cylinder 51. The retracting force E (force in the direction opposite to the propulsion direction A of the metal tube 10) 51 can be applied to the second guide wheel 52.

  The child cylinder 51 has a maximum output smaller than that of the parent cylinder 41. If the child cylinder 51 is used, the compression force that can be applied to the metal pipe 10 is smaller than that of the parent cylinder 41. A small compressive force can be accurately applied to the metal tube 10. The radius R2 of the second guide wheel 52 is smaller than the distance R3 between the holding position G of the metal tube 10 by the clamp portion 22 and the support shaft 23, and the second guide wheel 52, the chain 53, and the child cylinder 51 are made of metal. It is located closer to the support shaft than the tube 10. Therefore, even if the second guide wheel 52, the chain 53, and the child cylinder 51 are provided above the metal tube 10, the metal tube 10 is not obstructed.

  Further, this child cylinder 51 can reduce or prevent the above-described problem of the arm 21 falling. Specifically, if the clamp arm 21 that receives the propulsive force A of the metal tube 10 is supported by only the lower support shaft 24, the clamp arm 21 will fall as shown by the arrow F in FIG. In order to prevent this, in the present embodiment, the support shaft 23 is also provided at the upper end portion to support the arm 21, and the child cylinder 51 (second guide wheel 52) is connected to the upper end portion of the arm 21. Therefore, in the present embodiment, by using the child cylinder 51, it is possible to apply a pulling force E to the upper end portion of the arm 21 at the same time as applying a compressive force to the metal tube 10 and thereby canceling the fall of the arm 21. The occurrence of machining errors can be prevented by suppressing or preventing the arm 21 from falling.

  The compression control unit 45 controls the compression cylinders (the parent cylinder 41 and the child cylinder 51). The compression control unit 45 constitutes a hydraulic circuit 71 (see FIG. 5) that supplies hydraulic oil selectively to the compression cylinders 41 and 51 (to either one or both of the parent cylinder 41 and the child cylinder 51).

  Specifically, as shown in FIG. 5, the hydraulic circuit 71 includes a hydraulic oil supply unit 72 including a hydraulic pump, an oil tank, piping, and accessory devices (pressure gauge, filter, etc.), and a pressure region having a high pressure setting range. The first proportional relief valve 74, the second proportional relief valve 75 in the pressure region where the pressure setting range is low, and the relief valve interposed between the hydraulic oil supply unit 72 and the cylinder are selected (first proportional relief valve). Via an electromagnetic switching valve (proportional relief valve switching electromagnetic valve) 73, which is switched between the relief valve 74 and the second proportional relief valve 75, or one of the first proportional relief valve 74 and the second proportional relief valve 75. A switching valve (cylinder switching electromagnetic valve) 76 that switches the flow path of the hydraulic oil so that the hydraulic oil supplied from the hydraulic oil supply unit 72 is supplied to one or both of the parent cylinder 41 and the child cylinder 51; A controller (not shown) for controlling the control valves (proportional relief valves 74 and 75, switching valves 73 and 76), and using either the first proportional relief valve 74 or the second proportional relief valve 75. Then, one or both of the parent cylinder 41 and the child cylinder 51 are operated.

  Table 1 below shows an example of a processing method using the relief valves 74 and 75 and the compression cylinders 41 and 51. In this example, the maximum output (maximum tensile force) of the parent cylinder 41 is 1500 kN, the maximum output (maximum tensile force) of the child cylinder 51 is 150 kN, and the pressure setting range of the first proportional relief valve 74 is 2 to 20 MPa. The pressure setting range of the second proportional relief valve 75 is 0.7 to 7 MPa. In Table 1, a circle (◯) indicates use, and a cross (×) indicates non-use.

  As shown in Table 1 above, when the required compression force is large (example 1: 500 to 1500 kN), for example, when a small thickness reduction rate is required, the pressure setting range is high (high pressure region). The first proportional relief valve 74 is used to apply compressive force using both the parent cylinder 41 and the child cylinder 51. When the required compressive force is slightly smaller than this (example 2: 100 to 1000 kN), the first proportional relief valve 74 is similarly used, but only the parent cylinder 41 is used. When the required compression force is even smaller (example 3: 50 to 500 kN), the second proportional relief valve 75 having a low pressure setting range (in the low pressure region) is used to switch the parent cylinder 41. Operate. Furthermore, when the required compression force is very small (example 4: 30 to 150 kN), the second proportional relief valve 75 having a low pressure setting range (in the low pressure region) is used, and the output is small. A compression force is applied using only the child cylinder 51.

  As described above, according to the apparatus of this embodiment, an accurate compression force can be obtained by selectively using the optimum relief valves 74 and 75 and the cylinders 41 and 51 corresponding to the required compression force. Can be bent.

  The carriage 16 includes a clamp portion (rear clamp) 18 that holds the rear portion of the metal tube 10 and includes a wheel 19, and can travel toward the clamp arm 21 as the metal tube 10 is propelled. The carriage 16 is provided with thrust cylinders 31, 31 a that give a thrust to the metal pipe 10. The thrust cylinders 31, 31 a are engaged with the cart 16 and the arch portion 13 of the main body frame 11 to draw the cart 16 toward the arch portion (see arrow C), thereby causing the cart 16 to advance, and thereby the cart 16. The metal tube 10 fixed (gripped) is pushed forward toward the heating coil 20.

  On the other hand, the front end portion of the metal tube 10 is fixed (gripped) to the arm 21 by the clamp portion 22. Therefore, the arm 21 rotates as the metal tube 10 advances, and the gripping point of the metal tube 10 turns around the support shafts 23 and 24. In this way, the metal tube 10 is guided by the arm 21, and the heated portion of the metal tube 10 by the heating coil 20 is continuously plastically deformed and curved, and the grip points (clamp portion 22) by the support shafts 23 and 24 and the arm 21. The metal tube 10 can be bent into an arc shape whose radius is the distance to (see FIG. 4).

  At the same time, a compressive force is applied to the metal tube 10 by using one or both of the parent cylinder 41 and the child cylinder 51. The retracting forces D and E by the compression cylinders 41 and 51 are forces in the direction opposite to the propelling direction A of the metal tube 10 as described above, and the parent cylinder 41 is passed through the first guide wheel 42 and the clamp arm 21. The child cylinder 51 acts on the metal pipe 10 as a compressive force in the pipe axis direction via the second guide wheel 52 and the clamp arm 21 to suppress the thinning of the outer peripheral portion of the pipe. I can do it.

  In the present embodiment, the thrust cylinders 31 and 31a are provided in total, two in each of the upper position and the lower position of the carriage 16. However, in FIG. The lower thrust cylinder 31a is not shown. The lower thrust cylinder 31a (see FIG. 3) is installed at a position (a position directly below the upper thrust cylinder 31) that overlaps the upper thrust cylinder 31 when viewed from the plane (FIG. 1), and from the front (FIG. 2). When viewed, it is provided in front of the parent cylinder 41. Further, both the upper and lower thrust cylinders 31 and 31 a are arranged so that the extending directions of the piston rods coincide with the support shafts 23 and 24.

  The thrust cylinders 31 and 31a are controlled by a propulsion control unit 32 as shown in FIG. The propulsion control unit 32 includes a hydraulic drive circuit that supplies hydraulic oil to the thrust cylinders 31 and 31a, a pressure relief valve, a control unit that controls the amount of oil supply, and the like. Speed control is performed so that the tube 10) advances.

  Although the embodiment of the present invention has been described above, the present invention is not limited to this, and it will be apparent to those skilled in the art that various modifications can be made within the scope of the claims. .

  For example, in the above-described embodiment, a chain and a guide wheel (sprocket) are used as a mechanism (compression drive unit, guide wheel) for applying a compressive force to the metal tube, but a rack and pinion, a wire and a winding drum, or It is also possible to employ other power transmission mechanisms such as gears. The propulsion means and the compression means (compression drive means) typically use a hydraulic cylinder, but are not limited to this. For example, use of other drive devices such as a hydraulic motor, an electric motor, and an air cylinder. The present invention does not exclude.

  Further, the clamp means for gripping the metal tube is not limited to the above as long as it can withstand a bending moment applied to the metal tube and does not cause a slip with respect to an axial force in the tube axis direction (thrust in the tube longitudinal direction). Various mechanisms may be used. The structure of the propulsion means is not particularly limited as long as it is a mechanism capable of moving the metal tube. In addition to the examples shown in the drawings, various mechanisms and structures can be used for the clamp arm, the carriage, and the like.

  In the present invention, the material and dimensions (outer diameter / inner diameter / thickness dimension) of the metal tube to be processed are not particularly limited. For example, the present invention can process pipes made of materials mainly composed of iron (for example, steel pipes, stainless steel pipes, special steel pipes, etc.), but tubes and other metal alloys mainly composed of other metal materials. It may be a tube made of a material.

A Metal tube thrust (propulsion direction)
B Bending direction of the clamp arm C Pulling force by the thrust cylinder D, E Pulling force by the compression cylinder F Folding of the arm 10 Metal pipe 11 Body frame 12 Bottom plate part 13 Arch part 14 Post part 15 Beam part 16 Carriage 18, 22 Clamp Part 19 Wheel 20 Heating coil 21 Clamp arm 23, 24 Support shaft 31, 31a Thrust cylinder 32 Propulsion control part 41 Parent cylinder (compression cylinder)
42 First guide wheel 43, 53 Chain 45 Compression control unit 51 Child cylinder (compression cylinder)
52 Second guide wheel 61 Wire 62 Crane hook 71 Hydraulic circuit for compression 72 Hydraulic oil supply section (hydraulic pump, oil tank, etc.)
73 Solenoid switching valve (Proportional relief valve switching solenoid valve)
74 1st proportional relief valve 75 2nd proportional relief valve 76 Solenoid switching valve (solenoid valve for cylinder switching)

Claims (7)

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;
A movable base having a rear clamp for gripping the rear portion of the metal tube and transmitting a propulsive force to the metal tube and capable of traveling toward the heating means;
A compressive force is applied to the metal tube by applying a pulling force, which is a force in the direction opposite to the propulsion direction of the metal tube by the propulsion means, to the metal tube via the clamp arm with the support shaft as a fulcrum. Compression means;
A metal pipe bending apparatus comprising:
The compression means includes
First compression drive means;
Second compression drive means having a smaller output than the first compression drive means;
A compression control unit for controlling the first compression drive means and the second compression drive means,
The compression controller can apply the pulling force to the metal tube using either one or both of the first compression driving means and the second compression driving means ,
The support shaft extends in a vertical direction,
The clamp arm pivots horizontally as the metal tube is propelled to guide the metal tube,
While placing the support shaft and the second compression drive means on one side across the metal tube when viewed from a plane,
An apparatus for bending a metal tube , wherein the first compression driving means is disposed on the other side of the metal tube and below the metal tube when viewed from a plane . The compression means includes
While having a first hydraulic cylinder as the first compression drive means,
A second hydraulic cylinder as the second compression drive means;
The compression control unit
A first proportional relief valve;
A second proportional relief valve,
These first proportional relief valve and second proportional relief valve have a maximum settable pressure that is greater for the first proportional relief valve than for the second proportional relief valve,
The working oil is supplied to one or both of the first hydraulic cylinder and the second hydraulic cylinder through one of the first proportional relief valve and the second proportional relief valve, and the retracting force is supplied to the metal. The metal pipe bending apparatus according to claim 1, which is applied to the pipe. The compression means includes
A first guide wheel fixed to the clamp arm and rotating together with the clamp arm;
A first connecting member that transmits the force output from the first compression driving means to the first guide wheel;
A second guide wheel fixed to the clamp arm and rotating together with the clamp arm;
Bending apparatus of a metal tube according to claim 1 or 2 further comprising a second coupling member for transmitting the force output from the second compressing driving means to said second guide wheels. The metal pipe bending apparatus according to claim 3 , wherein a diameter of the first guide wheel is larger than a distance from the support shaft to a gripping point of the metal pipe. A diameter of the second guide wheel is smaller than a distance from the support shaft to the metal pipe;
The metal pipe bending apparatus according to claim 3 or 4 , wherein the second guide wheel and the second connecting member are disposed so as to be accommodated on the one side. The clamp arm includes a clamp portion that holds the metal tube at a middle portion in the vertical direction, and is supported rotatably by the support shaft at positions above and below the clamp portion.
Fixing the first guide wheel at a position below the clamp part;
The metal pipe bending apparatus according to any one of claims 3 to 5 , wherein the second guide wheel is fixed at a position above the clamp portion. The metal pipe bending apparatus according to any one of claims 1 to 6 , wherein the propulsion unit is disposed on the one side.

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