Clamping device, pipe bending machine and pipe bending method

Abstract

The invention discloses a clamping device, a pipe bending machine and a pipe bending method. The clamping device comprises a rotating assembly and a clamping table. The clamping assemblies are distributed oppositely and comprise translation units and clamping units; the translation unit comprises a single-action hydraulic cylinder which comprises a cylinder barrel and a piston assembly, and the cylinder barrel is internally provided with a reset piece and is provided with an air port; the working modes of the switching valve comprise an oil supply mode, an oil discharge mode and an oil separation mode; the clamping unit comprises a clamping mechanism, and the clamping mechanism comprises a clamping piece and an extrusion piece. According to the clamping device, the pipe bending machine and the pipe bending method, surface contact is achieved through the clamping pieces and a pipeline, the pressure area is increased, under the action of pressing force, the pressure intensity is reduced so as to avoid indentation, and in the pipe bending process, rodless cavities corresponding to hydraulic cylinders in the translation unit communicate with one another; hydraulic oil in the rodless cavities can be conveniently communicated with one another so as to automatically adjust the clamping force of the clamping pieces on the pipeline, so that the clamping force of the pipeline close to the bending position is uniform and consistent in the axial direction of the pipeline, and the pipe bending quality is improved.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of pipe bending, in particular to a clamping device, a pipe bending machine and a pipe bending method. BACKGROUND

[0002] The clamping die is an important component of the pipe bending machine, which is used for clamping and fixing the pipe, and drives the clamping die to rotate with the rotating device to realize the bending processing of the pipe. In order to prevent slipping, the inner wall of the clamping die is usually densely covered with grid-shaped protrusions to increase the roughness and thus increase the friction, so that the pipe is not easy to slip in the die, ensuring the positioning accuracy and processing quality of the pipe, and making the shape of the bent pipe meet the design requirements.

[0003] Although the grid-shaped protrusions on the inner wall of the die can play a certain positive role, the protrusion material is usually high in hardness and rough in surface, and in the clamping process, when the clamping force is too large and the pipe material is relatively soft, the contact part of the pipe and the protrusion is subjected to excessive stress, thereby causing scratches in the pipe bending process, affecting the pipe quality. Moreover, as the service time of the clamping device increases, the protrusions will be worn to some extent, and their surfaces will become smoother, thereby causing the clamping force of the protrusions on the pipe to decrease significantly, affecting the clamping effect and thus reducing the bending quality. In addition, during the pipe bending process, the pipe material near the bending position will undergo a large plastic deformation, and a greater resistance needs to be overcome to change the shape. Therefore, the protrusions near the bending position on the clamping device need to be clamped with a greater clamping force to fix the pipe and ensure that the pipe does not displace or slip during the bending process. However, in the prior art, the grid-shaped protrusions are usually uniform in height, and it is difficult to adjust the clamping force according to the stress generated when the pipe deforms, resulting in that the protrusions near the bending position are subjected to a greater force and produce more wear, while the protrusions far from the bending position are subjected to a relatively smaller counterforce and produce relatively less wear. As the service time increases, the difference in wear degree between the two positions increases, and therefore workers need to replace the grid-shaped protrusions on the clamping device periodically even if the clamping effect of some protrusions is still reliable, resulting in an increase in the processing cost of the pipe bending machine.

[0004] Therefore, it is necessary to improve the clamping device for the pipe bending machine in the prior art. SUMMARY

[0005] The present application aims to overcome the defects in the prior art and provide a clamping device, a pipe bending machine and a pipe bending method which can avoid the generation of scratches, ensure uniform clamping force during pipe bending, improve pipe bending quality and reduce replacement cost.

[0006] In order to solve the above technical problems, the present application provides a clamping device comprising: a rotating assembly driving the clamping table to rotate; a clamping assembly, distributed along a horizontal first direction on the same side of the rotation axis of the clamping table, comprising a translation unit and a clamping unit, the translation unit driving the clamping unit to move along the first direction to clamp the pipe, the axis of the pipe extending along a horizontal second direction perpendicular to the first direction in the clamped state, and the axis of the pipe being spaced from the rotation axis of the clamping table; the translation unit comprising: a single-acting hydraulic cylinder, distributed along the second direction, comprising a cylinder barrel fixed to the clamping table and a piston assembly sealingly penetrating one end of the cylinder barrel and forming a rod cavity and a rodless cavity with the cylinder barrel, the cylinder barrel having a reset member built-in to drive the piston assembly to the oil port and having an air port communicating with the rod cavity; a switching valve having a supply valve port for connecting the output end of the hydraulic pump, a discharge valve port for connecting the hydraulic tank, and a connection valve port communicating with each valve port, and having working modes including a supply mode, a discharge mode, and an isolation mode, in the supply mode, the supply valve port communicates with the connection valve port and is isolated from the discharge valve port, in the discharge mode, the connection valve port communicates with the discharge valve port and is isolated from the supply valve port, and in the isolation mode, the supply valve port, the discharge valve port, and the connection valve port are isolated from each other; the clamping unit comprising a clamping mechanism corresponding to the single-acting hydraulic cylinder, the clamping mechanism comprising a clamping piece and a pressing piece, the clamping piece being a deformable metal sheet connected to the piston assembly through the pressing piece, the clamping piece integrally formed with an arc-shaped groove extending along the second direction in a natural state, and the inner wall cross-sectional diameter of the arc-shaped groove being the same as the outer diameter of the pipe.

[0007] Preferably, to further facilitate clamping of the pipe during turning, the clamping unit further comprises a guide plate coaxial with the arc-shaped groove and located on the side of the arc-shaped groove opposite to the slot opening, the pressing piece comprises a pressing block connected to the piston assembly, a pressing protruding rod radially sliding through the guide plate and located between the pressing block and the clamping piece, and the guide plate and the pressing block slide relative to each other along the first direction and are limitingly connected.

[0008] Preferably, to ensure that one end of the pressing protruding rod is in full contact with the pressing block and the other end reduces damage to the clamping piece, prolonging the service life of the clamping piece, the end of the pressing protruding rod adjacent to the pressing block is provided with a resilient buffer pad, and the other end is hemispherical.

[0009] Preferably, to ensure the clamping quality of the pipe during long-term use, the clamping piece and the guide plate are detachably connected.

[0010] Preferably, in order to facilitate the detachable connection of the clamping piece, the clamping piece is connected with the guide plate through a magnetic connection structure, and the magnetic connection structure comprises two permanent magnets which are attracted to each other by magnetic force or a permanent magnet and a magnetic conductor which are attracted to each other by magnetic force.

[0011] Preferably, in order to ensure the clamping quality of the clamping piece, the clamping piece is a soft stainless steel sheet or a nickel-plated brass sheet with a thickness of 0.3-1 mm.

[0012] Preferably, in order to facilitate the connection between the single-direction hydraulic cylinder barrel and the hydraulic pump and the hydraulic tank, the switching valve comprises: A valve shell, which is a hollow cylinder, and the oil supply valve port, the oil discharge valve port and the connection valve port are all arranged on the circumferential outer edge of the valve shell; A valve core, the outer surface of which is sealingly attached to the inner wall of the valve shell and rotates around the axis of the valve core in the valve shell, and the valve core has an L-shaped flow channel, both ends of the flow channel extending to the circumferential outer edge of the valve core; An adjusting unit arranged in the valve core and driving the valve core to rotate.

[0013] In order to solve the above technical problems, the present application also provides a pipe bending machine, comprising: The clamping device in any one of the above technical solutions; A wheel mold seat fixed on the clamping table and having a wheel groove extending along a semicircular track on the circumferential outer edge, the rotation axis of the clamping table passing through the center of the extension track of the wheel groove, the inner wall cross section of the wheel groove being the same as the inner wall cross section of the arc-shaped groove in shape and size, and one end of the wheel groove being coaxially connected with the arc-shaped groove in the clamping assembly in the clamping state. A positioning assembly adjacent to the side of the wheel mold seat away from the clamping device, comprising a fixed mold seat, a movable mold seat and a movable unit, the fixed mold seat being fixedly arranged, and the movable unit driving the movable mold seat to close and open with the fixed mold seat, the fixed mold seat and the movable mold seat forming a positioning channel fitting the circumferential outer edge of the pipeline in the closed state, and the pipeline penetrating through the positioning channel and being adjacent to one end of the clamping device.

[0014] Preferably, in order to facilitate the axial positioning of the pipeline, the top surface of the fixed mold seat is provided with a lower positioning groove, the groove opening of the lower positioning groove facing upward, one surface of the movable mold seat adjacent to the fixed mold seat is provided with an upper positioning groove, the upper positioning groove being used to form a positioning channel with the lower positioning groove in the closed state, and the movable mold seat is rotationally connected with the fixed mold seat and the rotation axis is consistent with the extension direction of the lower positioning groove.

[0015] In order to solve the above technical problems, the present application also provides a pipe bending method, comprising the following steps: S10, preparation: straight pipe is placed on the fixed die seat, after adjusting the axial position of the pipe, the movable unit controls the movable die seat and the fixed die seat to close to form a positioning channel that fits the circumferential outer edge of the pipe, so that the pipe to be bent processing position is located outside the positioning channel; S20, clamping and positioning: at the end of the pipe to be bent away from the positioning channel, the opposite clamping assembly interacts to clamp the pipe; S30, bending processing: the clamping assembly is rotated to a preset angle by the rotating assembly, the rotation axis of the clamping assembly extends in the vertical direction and has a distance from the axis of the pipe; S40, product removal: the clamping assembly is separated, and the movable unit controls the movable die seat and the fixed die seat to separate, so as to remove the processed pipe; In step S20, the clamping assembly includes a translation unit and a clamping unit, the translation unit drives the clamping unit to move in a first direction, the first direction is parallel to the opposite distribution direction of the clamping assembly, and the axis direction of the pipe is horizontal in the second direction when clamping; The translation unit includes: Single-acting hydraulic cylinder, distributed in the second direction, including cylinder and piston assembly sealing through the cylinder near the pipe end and surrounding the cylinder to form a rod cavity and a rod cavity, the cylinder is built-in to drive the piston assembly to approach the oil port reset piece and has a gas port connected with the rod cavity; Switching valve, with oil supply valve port for connecting hydraulic pump output end, oil discharge valve port for connecting hydraulic tank and connection valve port connected with each oil port and working mode including oil supply mode, oil discharge mode and oil isolation mode, in oil supply mode, the oil supply valve port is connected with the connection valve port and is separated from the oil discharge valve port, in oil discharge mode, the connection valve port is connected with the oil discharge valve port and is separated from the oil supply valve port, in oil isolation mode, the oil supply valve port, the oil discharge valve port and the connection valve port are separated from each other; The clamping unit includes a clamping mechanism corresponding to the single-acting hydraulic cylinder, the clamping mechanism includes a clamping piece and an extrusion piece, the clamping piece is a deformable metal sheet connected with the piston assembly through the extrusion piece, the clamping piece integrally formed with an arc-shaped groove extending in the second direction in the natural state, the inner wall cross section inner diameter of the arc-shaped groove is the same as the outer diameter of the pipe.

[0016] Compared with the prior art, the clamping device, the pipe bending machine and the pipe bending method have the following advantages: the clamping device realizes surface contact with the pipe through the clamping piece and the pipe, the pressure area is increased, the pressure is reduced to avoid the generation of indentation under the action of the pressing force, the rodless cavities corresponding to the hydraulic cylinders in the translation unit are interconnected during the pipe bending process, the hydraulic oil in the rodless cavities is conveniently interconnected to automatically adjust the clamping force of the clamping piece on the pipe, the clamping force is uniform along the axial direction of the pipe near the bending position, and therefore the pipe bending quality is improved. BRIEF DESCRIPTION OF DRAWINGS

[0017] Figure 1 is a structure schematic view of the pipe bending machine of the present application when placing the pipe; Figure 2 is a structure schematic view of the pipe bending machine of the present application when adjusting the axial position after placing the pipe; Figure 3 is a structure schematic view of the pipe bending machine of the present application when radially positioning; Figure 4 is a structure schematic view of the pipe bending machine of the present application when clamping and positioning; Figure 5 is a connection structure schematic view of the rack and the positioning assembly of the present application; Figure 6 is an explosion schematic view of Figure 5 ; Figure 7 is a connection structure schematic view of the rack and the positioning assembly of the present application from another perspective; Figure 8 is a structure schematic view of the rack of the present application; Figure 9 is a structure schematic view of the clamping device of the present application; Figure 10 is an explosion schematic view of Figure 9 ; Figure 11 is a structure schematic view of the clamping assembly of the present application; Figure 12 is an explosion schematic view of Figure 11 ; Figure 13 is a structure schematic view of the switching valve of the present application; Figure 14 is an explosion schematic view of Figure 13 ; Figure 15 is a cross-sectional structure schematic view of Figure 14 ; Figure 16 is a structure schematic view of the single-acting hydraulic cylinder of the present application; Figure 17 is an explosion schematic view of Figure 16 ; Figure 18is a structural schematic diagram of the clamping unit of the present application; Figure 19 is Figure 18 an explosion schematic diagram; Figure 20 is Figure 18 a cross-sectional structural schematic diagram; In the figure: 1, rotating assembly; 11, gear; 12, rack; 13, telescopic unit; 131, telescopic motor; 132, telescopic screw rod; 133, telescopic screw sleeve; 2, clamping table; 21, wheel mold base; 22, supporting unit; 221, bottom foot; 222, supporting plate; 223, supporting bearing; 224, rotating disc; 23, supporting leg; 24, universal wheel; 25, concentric convex shaft; 3, translation unit; 31, single-acting hydraulic cylinder; 32, cylinder barrel; 321, barrel body; 322, cylinder cover 322; 323, air port; 3231, filter; 324, oil port; 33, piston assembly; 331, hydraulic piston; 332, piston rod; 333, connecting plate; 334, connecting bolt; 34, switching valve; 341, valve barrel; 3411, oil supply valve port; 3412, oil discharge valve port; 3413, connecting valve port; 342, valve cover; 35, valve core; 351, flow channel; 36, adjusting unit; 37, communication shell; 371, flow collecting port; 372, flow dividing port; 38, electromagnet; 4, clamping unit; 41, clamping mechanism; 411, clamping piece; 4111, positioning convex shaft; 4112, magnet conductor; 412, extrusion block; 4122, sliding groove; 4123, sliding rail; 4124, notch; 413, extrusion convex rod; 414, buffer pad; 5, guide plate; 51, permanent magnet; 52, arc plate; 521, sliding port; 522, positioning port; 53, sliding plate; 54, limiting tube; 55, fixing bolt; 6, pipeline; 7, positioning assembly; 71, fixed mold base; 711, lower positioning groove; 712, lower rotating seat; 713, rotating bolt; 72, movable mold base; 721, upper positioning groove; 722, convex strip; 723, upper rotating seat; 73, movable unit; 731, movable motor; 732, movable screw rod; 733, movable shaft sleeve; 734, movable block; 735, vertical strip; 7351, strip-shaped port; 736, rotating tube; 737, limiting bolt; 8, rack; 81, supporting table; 82, support column; 83, supporting roller; 84, moving motor; 85, moving roller; 86, guide frame; 87, guide rail. DETAILED DESCRIPTION

[0018] The specific embodiments of the present application will be further described below in conjunction with the accompanying drawings and examples. The following examples are only used to more clearly illustrate the technical solutions of the present application, and cannot be used to limit the protection scope of the present application.

[0019] As Figures 9-20 shown, the clamping device of the present application comprises: The rotating assembly 1 drives the clamping table 2 to rotate; The clamping assembly is opposite to the same side of the rotating axis of the clamping table 2 along a horizontal first direction, and comprises a translation unit 3 and a clamping unit 4, the translation unit 3 drives the clamping unit 4 to move along the first direction to clamp the pipeline 6, and the axis of the pipeline 6 extends along a second direction which is horizontal and perpendicular to the first direction in the clamping state, and the axis of the pipeline 6 is spaced from the rotating axis of the clamping table 2. The translation unit 3 comprises: The single-acting hydraulic cylinder 31 is distributed along the second direction, and comprises a cylinder barrel 32 fixed to the clamping table 2 and a piston assembly 33 sealed through one end of the cylinder barrel 32 and surrounded by the cylinder barrel 32 to form a rod cavity and a rodless cavity, the cylinder barrel 32 is internally provided with a reset member for driving the piston assembly 33 to approach the oil port 324 and has an air port 323 in communication with the rod cavity; The switching valve 34 has a supply valve port 3411 for connecting the output end of the hydraulic pump, a discharge valve port 3412 for connecting the hydraulic tank, and a connection valve port 3413 in communication with each oil port 324, and the working modes include a supply mode, a discharge mode and an isolation mode, in the supply mode, the supply valve port 3411 is in communication with the connection valve port 3413 and is isolated from the discharge valve port 3412, in the discharge mode, the connection valve port 3413 is in communication with the discharge valve port 3412 and is isolated from the supply valve port 3411, and in the isolation mode, the supply valve port 3411, the discharge valve port 3412 and the connection valve port 3413 are isolated from each other; The clamping unit 4 comprises a clamping mechanism 41 corresponding to the single-acting hydraulic cylinder 31, the clamping mechanism 41 comprises a clamping piece 411 and a pressing member, the clamping piece 411 is a deformable metal sheet connected with the piston assembly 33 through the pressing member, and the clamping piece 411 integrally formed with an arc-shaped groove extending along the second direction in a natural state, and the inner wall cross-section inner diameter of the arc-shaped groove is the same as the outer diameter of the pipeline 6.

[0020] It should be noted that the specific connection structure relationship of the hydraulic pump and the hydraulic tank connected by the switching valve 34 in the present application is that the input end of the hydraulic pump is in communication with the inner cavity of the hydraulic tank, the discharge valve port 3412 is in communication with the inner cavity of the hydraulic tank, and the hydraulic tank is used for storing hydraulic oil.

[0021] In the clamping device, the pipeline 6 is clamped by the opposite clamping assemblies cooperating with each other, and the clamping effect of the pipeline 6 is realized, and the clamping assembly mainly comprises the translation unit 3 and the clamping unit 4, wherein the translation unit 3 drives the clamping unit 4 to move, the two clamping units 4 are cooperated with each other to press and fix the pipeline 6, the clamping pieces 411 in the translation unit 3 and the clamping unit 4 are corresponding and drivingly connected, and the translation unit 3 further comprises the switching valve 34, the switching valve 34 is in different working modes according to different use states, as described below.

[0022] Firstly, when the pipe 6 to be bent is placed between the opposite clamping assemblies, the switching valves 34 on both sides are in the oil supply mode. In this mode, the hydraulic pump draws hydraulic oil in the hydraulic tank, and then delivers it to the rodless cavity of each single-acting hydraulic cylinder 31 through the switching valve 34, so that the piston assembly 33 moves outward, and the clamping piece 411 is driven by the extrusion piece to approach the pipe 6, and finally the clamping piece 411 abuts on the circumferential outer edge of the pipe 6. Since the clamping piece 411 is integrally formed with an annular groove in the natural state, the inner diameter of the annular groove is consistent with the outer diameter of the pipe 6, and finally the pressure of the hydraulic oil is transmitted to the piston assembly 33, and then the piston assembly 33 applies pressure to the clamping piece 411, so that the clamping piece 411 locks and fixes the pipe 6. Since the clamping piece 411 is in contact with the pipe 6, the contact area between the two is ensured, the pressure on the pipe 6 is reduced, and the pressure marks generated during the extrusion and fixation process are avoided.

[0023] When the clamping piece 411 locks and fixes the pipe 6, the switching valve 34 is adjusted to the oil isolation mode. In this working mode, the oil supply valve port 3411, the oil discharge valve port 3412 and the connecting valve port 3413 are mutually isolated, so that the hydraulic tank and the rodless cavity of the cylinder barrel 32 no longer have mutual flow of hydraulic oil, and the rodless cavities of the single-acting hydraulic cylinders 31 in the two clamping assemblies are connected to each other, the total amount of hydraulic oil is constant, and the extrusion force of each clamping mechanism 41 on the pipe 6 is fixed.

[0024] In this state, the rotating assembly 1 is started to drive the clamping table 2 to rotate, so that the clamping assemblies on the clamping table 2 rotate. Since the clamping assemblies have clamped the pipe 6 at this time, the part of the pipe 6 clamped by the clamping assemblies is relatively fixedly connected with the clamping assemblies and the clamping table 2, and then drives the clamped position of the pipe 6 to rotate, so as to realize the bending processing of the pipe 6.

[0025] In the bending process of the pipeline 6, the shape of the bending position of the pipeline 6 changes, so that stress is generated near the bending position of the pipeline 6, and the closer to the bending position, the stronger the stress, and the farther away from the bending position, the weaker the stress. For the same side extrusion assembly, the switching valve 34 is in the oil separation mode, in which mode, the rodless cavity of the cylinder barrel 32 of the single-acting hydraulic cylinder 31 is connected to each other, and the clamping piece 411 can transmit pressure to the piston assembly 33 of the single-acting hydraulic cylinder 31 through the extrusion piece, so that in the position where the pipeline 6 has relatively large stress, the hydraulic oil in the rodless cavity of the single-acting hydraulic cylinder 31 flows to the hydraulic oil in the rodless cavity of the single-acting hydraulic cylinder 31 in the position where the pipeline 6 has relatively small stress, that is, in the two clamping assemblies, the extrusion force near the bending position of the pipeline 6 is gradually reduced, and the extrusion force far away from the bending position of the pipeline 6 is gradually increased, while the total amount of the extrusion fastening force on both sides is fixed, so that the extrusion and fixing effect on the pipeline 6 is ensured, and the clamping piece 411 is a deformable metal sheet, which can adapt to the shape change of the pipeline 6 through slight deformation, ensure the connection between the surfaces of the clamping piece 411 and the pipeline 6, reduce the pressure, and further avoid the generation.

[0026] Furthermore, through the above design, in the bending process, the extrusion force of the clamping piece 411 on the pipeline 6 near the bending position of the pipeline 6 can be ensured to be uniform along the axial direction of the pipeline 6, so that the damage degree of the clamping piece 411 is basically uniform, and the clamping piece 411 near the bending position is less likely to be deformed and worn, and thus, after the switching valve 34 is adjusted to the oil separation mode, the rodless cavities in the cylinder barrels 32 of the single-acting hydraulic cylinders 31 are connected, the flow of the hydraulic oil is facilitated, the clamping piece 411 can promote the flow of the hydraulic oil according to the pressure applied to the pipeline 6 during bending and deformation, so that the extrusion force and the wear degree of the clamping piece 411 on the pipeline 6 are uniform, the extrusion force is automatically and dynamically adjusted along the axial direction of the pipeline 6, and the service life of the clamping piece 411 is prolonged.

[0027] Finally, after the bending is completed, the switching valve 34 is adjusted to the oil discharge mode, the hydraulic oil in the rodless cavities of the single-acting hydraulic cylinders 31 in the clamping assemblies is discharged, the piston assembly 33 is retracted, and the clamping pieces 411 on both sides are driven away from each other, so that the completed pipeline is taken out.

[0028] Specifically, in the present application, the clamping table 2 of the clamping device and the rotating assembly 1 are structured as Figure 9 and Figure 10As shown, the clamping table 2 is horizontally arranged, and the clamping table 2 comprises two parts, a first part is a rectangular plate, the length direction of the rectangular plate is parallel to the first direction, and the width direction is parallel to the second direction, and a second part is a semicircular plate located at the same horizontal plane as the rectangular plate, the semicircular plate is integrally formed on the long side of the rectangular plate and located on one side of the midpoint line of the two long sides of the rectangular plate, in the clamping state, the pipeline 6 is parallel to the midpoint line of the two long sides of the rectangular plate and located in the same vertical plane, the clamping assembly is provided with two, which are distributed on the midpoint line of the two long sides of the rectangular plate, the rotation axis of the clamping table 2 coincides with the axis of the semicircular plate, so that the axis of the pipeline 6 and the rotation axis of the clamping table 2 are separated during the pipe bending operation.

[0029] The lower side of the rectangular plate is fixed with a support 23 extending in the vertical direction, the bottom end of the support 23 is provided with a universal wheel 24 connected with the ground, which facilitates the rolling of the universal wheel 24 on the ground, and the lower side of the clamping table 2 is further fixed with a concentric convex shaft 25 coaxial with the semicircular plate, the concentric convex shaft 25 is connected with a supporting unit 22, so as to support the clamping table 2 to rotate stably with the axis of the semicircular plate as the center line.

[0030] Specifically, the supporting unit 22 comprises a rotating disc 224, a supporting bearing 223, a supporting plate 222 and a bottom foot 221 arranged in sequence from bottom to top, the rotating disc 224 is fixed to the bottom end of the concentric convex shaft 25, the inner ring top of the supporting bearing 223 is fixedly connected with the bottom surface of the rotating disc 224, the outer ring is fixed to the bottom surface of the supporting plate 222, the top end of the bottom foot 221 is fixedly connected with the supporting plate 222, and the bottom end is connected with the ground, so as to facilitate the stable rotation of the clamping table 2 after the operation of the rotating assembly 1.

[0031] The rotating assembly 1 comprises a gear 11, a rack 12 and a telescopic unit 13, specifically, the gear 11 is annular and fixedly sleeved on the outside of the concentric convex shaft 25, the rack 12 is engaged with the gear 11 and the length direction is parallel to the width direction of the rectangular plate, i.e. the first direction, and the telescopic unit 13 drives the rack 12 to move along the length direction of the rack 12, thereby driving the gear 11 to rotate, so that the concentric convex shaft 25 drives the clamping table 2 above it to rotate with the axis of the semicircular plate as the center line.

[0032] Further specifically, the telescopic unit 13 comprises a telescopic motor 131, a telescopic screw rod 132 and a telescopic screw sleeve 133, the telescopic motor 131 is fixedly arranged, the output end thereof is axially parallel to the length direction of the rack 12 and is fixedly connected with the telescopic screw rod 132, the telescopic screw sleeve 133 is threadedly connected with the telescopic screw rod 132 and is fixed above the rack 12, in this way, when the telescopic motor 131 operates, the telescopic screw rod 132 is driven to rotate, the telescopic screw sleeve 133 is driven to move along the first direction through the screw thread effect, and then the rotation of the clamping table 2 can be realized.

[0033] The single-acting hydraulic cylinder 31 transmits pressure through the oil inside, and the specific structure is shown in Figure 12 、 Figure 16 and Figure 17 , in the single-acting hydraulic cylinder 31, the cylinder barrel 32 comprises a barrel body 321 and a barrel cover 322 fixedly connected, the barrel body 321 is fixed above the clamping table 2 and is axially parallel to the second direction, the barrel cover 322 is fixed to one end of the barrel body 321 adjacent to the clamping piece 411, the other end of the barrel body 321 is closed, and the bottom of the barrel body 321 is respectively provided with an oil port 324 and an air port 323, wherein the oil port 324 is used to introduce hydraulic oil into the rodless cavity or discharge the hydraulic oil in the rodless cavity, and the air port 323 is used to facilitate the communication between the rod cavity and the outside, the air port 323 is provided with a filter element 3231, the filter element 3231 comprises a filter pipe threadedly connected with the air port 323 and a filter screen fixed to the end of the filter pipe, so as to avoid the external impurities entering the cylinder barrel 32 during the air permeation process, causing the abrasion between the inner wall of the cylinder barrel 32 and the piston assembly 33 to cause the sealing performance to be reduced, and the filter element 3231 is threadedly connected with the air port 323, so as to facilitate the replacement and maintenance of the filter element 3231.

[0034] The piston assembly 33 comprises a piston rod 332 and a connecting plate 333 and a hydraulic piston 331 integrally connected to both ends of the piston rod 332, the circumferential outer edge of the hydraulic piston 331 is sealingly connected with the circumferential inner wall of the barrel body 321 and slides along the axial direction of the barrel body 321 between the air port 323 and the oil port 324, the piston rod 332 sealingly penetrates the barrel cover 322, and the connecting plate 333 is connected with the extrusion piece, in this way, the movement of the piston assembly 33 is realized through the change of the hydraulic oil in the rodless cavity inside the cylinder barrel 32, and then the extrusion piece is driven to move.

[0035] The single-acting hydraulic cylinder 31 further comprises a reset element arranged inside, which is used to push the piston assembly 33 to be close to the oil port 324, and discharge the hydraulic oil in the rodless cavity through the oil port 324, in the present application, the reset element comprises two electromagnets 38 repelling each other, which are fixed to the two opposite surfaces of the barrel cover 322 and the hydraulic piston 331 respectively.

[0036] The reset spring is generally used as the reset member in the prior art, but the reset spring is prone to aging after multiple uses, affecting the reset force, and the elastic force of the reset spring cannot be accurately controlled. In the present application, two electromagnets 38 repelling each other are selected to form the reset member. When the hydraulic oil in the rodless cavity needs to be extruded, the two electromagnets 38 are powered to generate a magnetic field repelling each other, thereby pushing the piston assembly 33 to retreat. Therefore, compared with the reset spring used as the reset member, the two electromagnets 38 used as the reset member have the following advantages. First, the mechanical wear of the spring can be avoided, and the service life of the reset member is longer. Second, the reset force can be flexibly adjusted. The elastic force of the reset spring is determined by the elastic coefficient and the elastic deformation amount, and the elastic coefficient changes with the increase of the use time, which cannot be accurately controlled. However, the repelling force of the magnetic field can be accurately controlled by controlling the current of the two electromagnets 38. Third, the reset spring is prone to relaxation or rupture, while the electromagnets 38 only need to ensure that the coil works normally to achieve stable resetting of the piston assembly 33, so that the reset member composed of the electromagnets 38 has higher reliability.

[0037] In order to facilitate the flexible switching of the switching valve 34 between the oil supply mode, the oil discharge mode and the oil isolation mode, the switching valve 34 comprises: A valve shell, which is a hollow cylinder, the oil supply valve port 3411, the oil discharge valve port 3412 and the connecting valve port 3413 are all arranged on the circumferential outer edge of the valve shell; A valve core 35, the outer surface of which is sealingly attached to the inner wall of the valve shell and rotates around the axis of the valve core 35 in the valve shell, the valve core 35 has an L-shaped flow channel 351 extending to the circumferential outer edge of the valve core 35 at both ends; An adjusting unit 36 arranged in the valve core 35 and driving the valve core 35 to rotate.

[0038] After the above design, the valve core 35 in the valve shell is controlled to rotate by the adjusting unit 36, the position of the flow channel 351 on the valve core 35 is adjusted, and the conversion of the three working modes is realized. Specifically, when the two ends of the flow channel 351 are respectively connected in communication with the oil supply valve port 3411 and the connecting valve port 3413, the switching valve 34 is in the oil supply mode. When the two ends of the flow channel 351 are respectively connected in communication with the oil discharge valve port 3412 and the connecting valve port 3413, the switching valve 34 is in the oil discharge mode. In other cases, the switching valve 34 is in the oil isolation mode.

[0039] Further specifically, as Figures 11-15As shown, the valve housing includes a top open and barrel-shaped valve barrel 341 and a valve cover 342 fixed on the top of the valve barrel 341, the oil supply valve port 3411, the connection valve port 3413 and the oil discharge valve port 3412 are sequentially distributed on the circumferential outer edge of the valve barrel 341, wherein the oil supply valve port 3411 and the oil discharge valve port 3412 are coaxially arranged back to back, the axis of the connection valve port 3413 is perpendicular to the axis of the oil supply valve port 3411, the adjusting unit 36 includes a stepper motor fixed on the valve cover 342, the stepper motor is arranged downward, the output shaft is sealed and penetrates through the valve cover 342 and is fixedly connected with the valve core 35 coaxially, the step angle of the stepper motor is 90°, and in the initial position, the two ends of the flow channel 351 are respectively communicated with the oil supply valve port 3411 and the connection valve port 3413, that is, the switching valve 34 is in the oil supply mode, as shown in Figure 15 As shown, the rotation direction of the valve core 35 is counterclockwise.

[0040] After the above design, in the initial state, the switching valve 34 is in the oil supply mode, the hydraulic pump can extract the hydraulic oil in the hydraulic tank and deliver it to the oil supply valve port 3411, the hydraulic oil is discharged from the connection valve port 3413 through the flow channel 351 and enters the rodless cavity in the cylinder barrel 32 of the single-acting hydraulic cylinder 31, and the piston assembly 33 is pushed to move outward, when the stepper motor drives the valve core 35 to rotate once and then rotates once again, at the end of the two rotation processes, one end of the flow channel 351 is blocked by the circumferential inner wall of the valve barrel 341, at this time, the switching valve 34 is in the oil isolation mode, the oil supply valve port 3411, the oil discharge valve port 3412 and the connection valve port 3413 are mutually isolated, and the total amount of hydraulic oil in the rodless cavity of the cylinder barrel 32 is fixed; when the stepper motor drives the valve core 35 to rotate for the fourth time, the two ends of the flow channel 351 are respectively communicated with the oil supply valve port 3411 and the connection valve port 3413, the reset member is started, the piston assembly 33 is pushed to move to the oil port 324, so that the hydraulic oil in the rod cavity is squeezed out of the oil port 324, enters the flow channel 351 through the connection valve port 3413, and then is discharged through the oil discharge valve port 3412 and flows into the hydraulic tank; then the stepper motor is operated again, so that the two ends of the flow channel 351 are respectively communicated with the oil supply valve port 3411 and the connection valve port 3413, and the switching valve 34 is in the oil supply mode. In this way, the stepper motor of the adjusting unit 36 rotates, and the switching valve 34 can realize the cyclic adjustment of the three working modes of "oil supply mode→oil isolation mode→oil isolation mode→oil supply mode".

[0041] Further, as shown in Figure 11 and Figure 12As shown, the translation unit 3 further comprises a hollow communication shell 37, the length direction of the communication shell 37 is parallel to the second direction, the communication shell 37 is fixed between each cylinder barrel 32 and the valve shell, specifically, the side wall of the communication shell 37 is provided with a flow collecting port 371, the top wall is provided with a flow dividing port 372, the flow collecting port 371 is fixedly communicated with the connecting valve port 3413, the flow dividing port 372 is fixedly communicated with the oil port 324 of each cylinder barrel 32 one by one, in this way, the mutual communication between the rodless cavities of each cylinder barrel 32 is realized, which facilitates the mutual flow of hydraulic oil between the rodless cavities under the influence of stress change during the bending process of the pipeline 6, and ensures that the fastening force received by each part of the pipeline 6 tends to be uniform.

[0042] Further improvement is that the clamping piece 411 is a soft stainless steel piece or a nickel-plated brass piece with a thickness of 0.3-1mm.

[0043] After adopting this design, on the one hand, the clamping piece 411 can deform to a certain extent after being subjected to extrusion force, that is, it has a certain flexibility, on the other hand, it is not easy to produce permanent deformation after being subjected to extrusion force, and the surface is easy to polish to a roughness of less than 0.8um, avoiding scratching the pipeline 6, ensuring sufficient contact pressure area between the clamping piece 411 and the pipeline 6, so as to reduce the pressure.

[0044] Further improvement is that the clamping unit 4 further comprises a guide plate 5 coaxial with the arc-shaped groove and located on the side of the arc-shaped groove opposite to the slot of the arc-shaped groove, the extrusion part comprises an extrusion block 412 connected with the piston assembly 33, an extrusion protruding rod 413 sliding through the guide plate 5 along the radial direction of the arc-shaped groove and located between the extrusion block 412 and the clamping piece 411, the guide plate 5 and the extrusion block 412 slide relative to each other along the first direction and are limitingly connected; the extrusion protruding rod 413 is provided with a elastic buffer pad 414 at one end adjacent to the extrusion block 412, and the other end is semispherical.

[0045] Specifically, as Figure 11 , Figure 12 , Figures 18-20As shown, in the present application, the extrusion blocks 412 in the clamping mechanism 41 are sequentially provided with five in the second direction, and the corresponding single-acting hydraulic cylinders 31 are also provided with five (of course, the number can also be flexibly adjusted), and the adjacent two extrusion blocks 412 are sequentially connected in close contact, and the two sides of the extrusion block 412 are provided with notches 4124, one side of the extrusion block 412 is fixedly connected with the connecting plate 333 through the connecting bolt 334, and the other side is a circular arc surface, the circular arc surface is coaxial with the arc-shaped groove and densely provided with extrusion protruding rods 413, the axial direction of the extrusion protruding rod 413 is parallel to the radial direction of the circular arc surface, and the bottom end of the extrusion block 412 is provided with a sliding groove 4122 extending in the first direction, the sliding groove 4122 is a through groove, and the clamping table 2 is fixedly provided with a sliding rail 4123 corresponding to the extrusion block 412, and the sliding groove 4122 and the sliding rail 4123 are in sliding fit, so that when the single-acting hydraulic cylinder 31 operates, the extrusion block 412 can move stably along the first direction.

[0046] The guide plate 5 includes three parts, the first part is an arc-shaped plate 52 located between the extrusion block 412 and the clamping piece 411, the cross section of the arc-shaped plate 52 is a semicircular arc, the inner diameter of the arc-shaped plate 52 is between the outer diameter of the outer wall of the clamping piece 411 and the inner diameter of the circular arc surface of the extrusion block 412, and the arc-shaped plate 52 is densely provided with sliding openings 521, and the extrusion protruding rod 413 is sealed and slid along the axial direction of the extrusion protruding rod 413 and penetrates the sliding opening 521; the second part is a sliding plate 53 integrally formed at both ends of the arc-shaped plate 52 and located on the side away from the clamping piece 411, the sliding plates 53 at both ends are in sliding fit with the notches 4124 on the outer side of the extrusion block 412 and penetrate the notches 4124; the third part includes a limiting tube 54 and a fixing bolt 55, the axial direction of the limiting tube 54 is parallel to the second direction, and the two ends of the limiting tube 54 are in close contact with the two sliding plates 53, respectively, the limiting tube 54 is located on the side of the extrusion block 412 away from the clamping piece 411 and is fixedly connected with the two sliding plates 53 through the two fixing bolts 55 at the two ends, in this way, the sliding and limiting connection of the guide plate 5 and the extrusion block 412 in the first direction is realized, and the limiting connection of the extrusion protruding rod 413 and the guide plate 5 in the radial direction of the arc-shaped groove is also realized, one side of the extrusion protruding rod 413 adjacent to the extrusion block 412 has a elastic buffer pad 414, the buffer pad 414 is preferably a rubber pad, and the outer diameter of the buffer pad 414 is greater than the inner diameter of the sliding opening 521, on the one hand, the extrusion protruding rod 413 is prevented from being separated from the sliding opening 521, and on the other hand, the sufficient contact area of the extrusion protruding rod 413 and the arc surface of the extrusion block 412 is ensured, so that the extrusion protruding rod 413 is prevented from being broken and damaged in the extrusion process.

[0047] With the above structure, the single-acting hydraulic cylinder 31 drives the extrusion block 412 to move along the length direction of the slide rail 4123, acts on the extrusion convex rod 413, acts on the clamping piece 411 through the extrusion convex rod 413, makes the clamping piece 411 move close to the pipeline 6, and finally makes the clamping piece 411 abut against the pipeline 6. Continue to input hydraulic oil into the rod cavity of the cylinder barrel 32, increase the hydraulic pressure, and make the extrusion block 412 continue to move. During the movement, the buffer pad 414 acts on the extrusion convex rod 413, so that the densely arranged extrusion convex rods 413 move along the length direction of the extrusion convex rods 413, that is, the pipeline 6 moves close to the axis of the pipeline 6 in the radial direction, extrudes the clamping piece 411, and realizes face contact to reduce the pressure while increasing the extrusion fixing force through the clamping piece 411. Preventing the pipeline 6 from appearing indentation on the surface; then the switch valve 34 is adjusted to the oil separation state, the extrusion fixing force of each extrusion block 412 on the clamping piece 411 is ensured, and thus the extrusion fixing force of the clamping piece 411 on the pipeline 6 is ensured. With the rotation of the rotating assembly 1, the pipeline 6 changes shape, stress is generated near the bending position of the pipeline 6, and the strength of the stress acts on the clamping piece 411. In the position where the stress is relatively strong, the extrusion convex rod 413 tends to move away from the axis of the pipeline 6, so that the extrusion convex rod 413 can act on the extrusion block 412, and then act on the piston assembly 33. Part of the hydraulic oil in the rod cavity of the cylinder barrel 32 near the bending position flows into the rod cavity of the cylinder barrel 32 away from the bending position through the communication shell 37, so as to automatically adjust the extrusion fixing force of each single-acting hydraulic cylinder 31. With the bending of the pipeline, the extrusion fixing force of the clamping piece 411 near the bending position on the pipeline 6 decreases, and correspondingly, the extrusion fixing force of the clamping piece 411 away from the bending position on the pipeline 6 increases, so as to ensure that the extrusion fixing force tends to be uniform, and thus the bending quality is improved.

[0048] The end of the extrusion convex rod 413 close to the clamping piece 411 is hemispherical, so that the extrusion surface of the extrusion convex rod 413 maintains a round shape, avoiding being too sharp to cause the clamping piece 411 to crack and damage.

[0049] Further improvement is that the clamping piece 411 is detachably connected with the guide plate 5. Since the clamping piece 411 bears the pressure of the extrusion convex rod 413 and the pipeline 6, the detachable connection facilitates the replacement of the worn clamping piece 411, so as to ensure the long-term stable clamping force of the clamping device.

[0050] Further improvement is that the clamping piece 411 is connected with the guide plate 5 through a magnetic connection structure, and the magnetic connection structure includes two permanent magnets 51 that are attracted to each other by magnetic force or a permanent magnet 51 and a magnetic conductor 4112 that are attracted to each other by magnetic force.

[0051] Specifically, as Figure 12 and Figure 19As shown, the upper and lower ends of the arc-shaped plate 52 are fixed with permanent magnets 51 extending along the first direction, the permanent magnets 51 are strips made of magnets, the upper and lower ends of the clamping piece 411, away from the arc-shaped groove, are fixed with magnetic conductors 4112 extending along the first direction, the magnetic conductors 4112 are strips supported by iron, through the magnetic attraction of the permanent magnets 51 and the magnetic conductors 4112, the clamping piece 411 is quickly installed on the inner side of the guide plate 5; in addition, the side of the clamping piece 411, away from the arc-shaped groove, is integrally formed with a positioning convex shaft 4111 extending along the radial direction thereof, the arc-shaped plate 52 is integrally formed with a positioning opening 522 extending along the radial direction thereof, the positioning convex shaft 4111 and the positioning opening 522 correspond to each other and are gap-fitted, so as to ensure that the clamping piece 411 is accurately installed on the inner side of the guide plate 5, and the axial position offset of the clamping piece 411 is avoided, thus facilitating the convenient and high-precision dismounting operation of the clamping piece 411.

[0052] Based on the above-mentioned clamping device, the present application further discloses a pipe bending machine. Figures 1-20 As shown, the pipe bending machine comprises the above-mentioned clamping device; a wheel mold seat 21 fixed on the clamping table 2 and provided with a wheel groove extending along a semicircular track at the circumferential outer edge, the rotation axis of the clamping table 2 passes through the center of the wheel groove extending track, the inner wall cross section of the wheel groove is the same as the inner wall cross section of the arc-shaped groove in shape and size, and one end of the wheel groove is coaxially connected with the arc-shaped groove in one of the clamping assemblies in the clamping state. a positioning assembly 7 adjacent to the side of the wheel mold seat 21 away from the clamping device, comprising a fixed mold seat 71, a movable mold seat 72 and a movable unit 73, the fixed mold seat 71 is fixedly arranged, the movable unit 73 drives the movable mold seat 72 to close and separate from the fixed mold seat 71, in the closed state, the fixed mold seat 71 and the movable mold seat 72 form a positioning channel fitting the circumferential outer edge of the pipeline 6, and the pipeline 6 penetrates the positioning channel and is adjacent to one end of the clamping device.

[0053] Specifically, the wheel mold seat 21 is fixed above the semicircular plate of the clamping table 2, and the projection of the wheel mold seat 21 on the horizontal plane is semicircular, the rotation axis of the clamping table 2 passes through the center of the semicircular projection, and one side of the semicircular projection is parallel to the second direction.

[0054] The positioning assembly 7 is arranged on the rack 8, the rack 8 comprises a horizontal support table 81, the length direction and the width direction of the support table 81 are parallel to the second direction and the first direction respectively, downward extending support columns 82 are fixed at the four corners of the support table 81, a telescopic motor 131 is fixed on the bottom surface of the support table 81, and a guide frame 86 extending along the second direction is also fixed on the bottom surface of the support table 81. Figure 8 As shown, the circumferential outer edge of the telescopic screw sleeve 133 is sealingly fitted with the circumferential inner wall of the guide frame 86, so as to realize the smooth movement of the telescopic screw sleeve 133 along the second direction.

[0055] Further improvement is that the top surface of the fixed die seat 71 is provided with a lower positioning groove 711, the notch of the lower positioning groove 711 is upward, the side of the movable die seat 72 adjacent to the fixed die seat 71 is provided with an upper positioning groove 721, the upper positioning groove 721 is used for forming a positioning channel with the lower positioning groove 711, the movable die seat 72 is rotationally connected with the fixed die seat 71 and the rotational axis is consistent with the extension direction of the lower positioning groove 711.

[0056] The movable die seat 72 is driven by the movable unit 73 to realize the clamping and demolding with the fixed die seat 71, in the demolding state, it is convenient to place the straight pipeline 6 to be processed in the lower positioning groove 711 or take out the processed pipeline 6 from the fixed die seat 71, in the clamping state, the lower positioning groove 711 of the fixed die seat 71 and the upper positioning groove 721 of the movable die seat 72 form a positioning channel, which can position the pipeline 6 in the radial direction and prevent the pipeline 6 from deviating in the radial direction, so that it is convenient for the clamping device to clamp the pipeline 6 which is fixed in the radial direction and then bend the pipeline.

[0057] As shown in Figures 5-6 , the fixed die seat 71 is a lower die seat fixed on the support table 81 and extending along the second direction, the movable die seat 72 is an upper die seat rotationally connected with the fixed die seat 71 and extending along the second direction, the lower positioning groove 711 and the upper positioning groove 721 are both through grooves with semicircular cross section and consistent inner diameter with the outer diameter of the pipeline 6, one side of the fixed die seat 71 is provided with two lower rotary seats 712 distributed along the second direction, the same side of the movable die seat 72 is provided with an upper rotary seat 723, the upper rotary seat 723 is attached between the two lower rotary seats 712, the lower rotary seat 712 is threadedly connected with a rotary bolt 713, the rotary bolt 713 includes a screw rod part and a light rod part integrally connected with the same axis, the screw rod part is threadedly connected with the lower rotary seat 712, the upper rotary seat 723 is sealingly sleeved on the light rod part, so that the movable die seat 72 is rotationally connected with the fixed die seat 71.

[0058] The top surface of the upper rotating seat 723 opposite to the upper positioning groove 721 is fixed with a convex strip 722, one end of the convex strip 722 is located above the side of the upper rotating seat 723 and the lower rotating seat 712, the movable unit 73 comprises a movable motor 731, a movable lead screw 732, a movable shaft sleeve 733, a movable block 734, vertical strips 735, a rotating pipe 736 and a limiting bolt 737, specifically, the movable lead screw 732 is axially parallel to the first direction, the movable motor 731 and the movable shaft sleeve 733 are both fixed above the supporting table 81, the movable motor 731 is drivingly connected with one end of the movable lead screw 732, the other end of the movable lead screw 732 is sealingly combined with the inner wall of the movable shaft sleeve 733, the movable block 734 is threadedly connected with the movable lead screw 732, the supporting table 81 is fixed with a guide rail 87 extending along the first direction, the movable block 734 is slidingly matched with the guide rail 87, the vertical strips 735 are provided with two and are fixed above the movable block 734, the two vertical strips 735 are combined with the two sides of the convex strip 722, the vertical strips 735 are provided with strip-shaped openings 7351 extending along the vertical direction, the rotating pipe 736 penetrates the strip-shaped openings 7351 and sealingly penetrates the end of the convex strip 722 located above the side of the lower rotating seat 712 and the upper rotating seat 723, the outer diameter of the rotating pipe 736 is same with the width of the strip-shaped opening 7351, the two ends of the rotating pipe 736 are threadedly connected with the limiting bolt 737, the cap portion of the limiting bolt 737 is combined with the surface of the vertical strip 735 opposite to the convex strip 722 and the outer diameter of the cap portion is greater than the width of the strip-shaped opening 7351, so as to prevent the rotating pipe 736 from being separated from the vertical strip 735 and the convex strip 722.

[0059] After the above structure is adopted, the movable motor 731 is started, the movable lead screw 732 is driven to rotate around the axis thereof under the guidance of the movable shaft sleeve 733, the movable block 734 and the vertical strips 735 are driven to move along the second direction through the thread action on the movable block 734, the rotating pipe 736 is driven to move, the position of the convex strip 722 is changed, the movable mold base 72 is driven to rotate with the axis of the rotating bolt 713 as the center line, when the movable mold base 72 rotates upward, the movable mold base 72 is separated from the fixed mold base 71, when the movable mold base 72 rotates downward to the coaxial line of the upper positioning groove 721 and the lower positioning groove 711, the movable mold base 72 is combined with the fixed mold base 71, the two form the positioning channel for axially positioning the pipeline 6.

[0060] The top surface of the fixed mold base 71 is also provided with an opening, and a moving roller 85 is arranged in the opening. The wheel surface of the moving roller 85 is tangent to the curved surface of the inner wall of the lower positioning groove 711. A moving motor 84 is fixed on the support table 81. The output shaft of the moving motor 84 is parallel to the first direction and is fixedly connected with the coaxial line of the moving roller 85. The end of the fixed mold base 71 opposite to the wheel mold base 21 is provided with a supporting roller 83. The wheel surface of the supporting roller 83 is also tangent to the curved surface of the inner wall of the lower positioning groove 711. The supporting roller 83 cooperates with the moving roller 85 to horizontally support the pipeline 6. After the moving motor 84 drives the moving roller 85 to rotate, the pipeline 6 above the moving roller 85 can also move axially, so as to adjust the axial position of the pipeline 6.

[0061] After the structure is adopted, before the mold is closed, the moving motor 84 drives the moving roller 85 to rotate, so as to conveniently adjust the axial position of the pipeline 6. When the mold is closed, the fixed mold base 71 and the movable mold base 72 axially position the pipeline 6 from the upper and lower directions, and the clamping device clamps the pipeline 6 in the horizontal direction, so as to ensure the positioning and clamping effect of the pipeline 6. When the rotating assembly 1 operates, the part of the pipeline 6 at the position of the positioning assembly 7 is prevented from axially deviating, so as to ensure the processing quality of the pipeline 6.

[0062] Based on the pipe bending machine, the application provides a pipe bending method, which comprises the following steps: S10, preliminary preparation: placing a straight pipeline 6 on the fixed mold base 71 (as shown in Figure 1 ), adjusting the axial position of the pipeline 6 (as shown in Figure 2 ), and then closing the movable mold base 72 and the fixed mold base 71 by the movable unit 73 to form a positioning channel that is fitted with the circumferential outer edge of the pipeline 6, so that the pipeline 6 to be bent and processed is located outside the positioning channel (as shown in Figure 3 ); S20, clamping and positioning: clamping and fixing the pipeline 6 (as shown in Figure 4 ) by the opposite clamping assemblies at the end of the pipeline 6 away from the positioning channel; S30, bending processing: rotating the clamping assemblies to a preset angle by the rotating assembly 1. The rotation axis of the clamping assemblies extends in the vertical direction and has a spacing from the axis of the pipeline 6. S50, taking out the product: separating the clamping assemblies, and separating the movable mold base 72 and the fixed mold base 71 by the movable unit 73, so as to take out the processed pipeline 6. In step S20, the clamping assembly comprises a translation unit 3 and a clamping unit 4. The translation unit 3 drives the clamping unit 4 to move in the first direction. The first direction is parallel to the opposite distribution direction of the clamping assembly. When clamping, the axis direction of the pipeline 6 is the horizontal second direction. The translation unit 3 comprises: Single-acting hydraulic cylinder 31, distributed along the second direction, includes cylinder 32 and sealing through cylinder 32 one end close to pipeline 6 and with cylinder 32 enclosed to form a piston assembly 33 with rod cavity and rodless cavity, cylinder 32 is built-in reset member to drive piston assembly 33 to approach oil port 324 and has air port 323 in communication with rod cavity; Switching valve 34, with oil supply valve port 3411 for connecting hydraulic pump output, oil discharge valve port 3412 for connecting hydraulic tank and connecting valve port 3413 in communication with each oil port 324 and working mode including oil supply mode, oil discharge mode and oil isolation mode, in oil supply mode, oil supply valve port 3411 is in communication with connecting valve port 3413 and is isolated from oil discharge valve port 3412, in oil discharge mode, connecting valve port 3413 is in communication with oil discharge valve port 3412 and is isolated from oil supply valve port 3411, in oil isolation mode, oil supply valve port 3411, oil discharge valve port 3412 and connecting valve port 3413 are isolated from each other; Clamping unit 4 includes clamping mechanism 41 corresponding to single-acting hydraulic cylinder 31, clamping mechanism 41 includes clamping piece 411 and extrusion piece, clamping piece 411 is a deformable metal sheet connected with piston assembly 33 through extrusion piece, in natural state, clamping piece 411 is integrally formed with arc-shaped groove extending along the second direction, the inner wall cross-section inner diameter of arc-shaped groove is the same as the outer diameter of pipeline 6.

[0063] Compared with the prior art, the pipeline 6 is bent by the above-mentioned pipe bending machine and pipe bending method, and the following beneficial effects are obtained during the whole pipe bending process: First, after the movable die seat 72 is separated from the fixed die seat 71, the straight pipeline 6 is conveniently placed horizontally through the lower positioning groove 711 on the fixed die seat 71 and the supporting roller 83 on the supporting table 81, and the pipeline 6 after pipe bending processing is also conveniently taken out; Second, the position of the pipeline 6 is conveniently adjusted by rotating the moving roller 85 driven by the moving motor 84, so that the pipeline 6 to be bent is protruded from the lower positioning groove 711; Third, the movable die seat 72 is rotated downward to be combined with the fixed die seat 71 by the action of the movable unit 73, and the movable die seat 72 is pressed on the pipeline 6 by the action force of the movable unit 73 and the gravity of the movable die seat 72, while the fixed die seat 71 is fixed in position, realizing high-precision radial positioning of the pipeline 6 and preventing the pipeline 6 from being deviated in the radial direction; Fourth, the positioning assembly 7 positions the pipeline 6 in the up-down direction, and the clamping device clamps and fixes the pipeline 6 in the horizontal direction, which is convenient for later bending processing and avoids the radial deviation of the pipeline 6 positioned by the positioning assembly 7, thereby being beneficial to the quality of later pipe bending; Fifth, the clamping device is in surface contact with the outer surface of the pipeline 6 through the clamping piece 411, which increases the pressure contact area and reduces the pressure on the pipeline 6 under the condition of ensuring the same pressure, thereby avoiding indentation on the outer surface of the pipeline 6. Sixth, the multiple extrusion rods 413 move radially to act on the clamping piece 411, thereby ensuring that the force on the part of the pipeline 6 corresponding to the same clamping piece 411 tends to be uniform. Seventh, after the switching valve 34 is adjusted to the oil separation mode, the rodless cavities of the single-acting hydraulic cylinders 31 in the same side clamping unit 4 are connected to each other, which can realize the automatic flow of hydraulic oil in the rodless cavities according to the pressure of the pipeline 6 on the clamping piece 411, thereby adjusting the pressure of each clamping piece 411. Specifically, when bending the pipeline, the pressure of the pipeline 6 on the clamping piece 411 is larger near the bending position, and the pressure of the pipeline 6 on the clamping piece 411 is smaller away from the bending position. At this time, the hydraulic oil in the cylinder barrel 32 corresponding to the position close to the bending position flows into the hydraulic oil in the cylinder barrel 32 away from the bending position, so that the piston assembly 33 close to the bending position retreats while the piston assembly 33 away from the bending position extends outward, thereby reducing the pressure of the clamping piece 411 close to the bending position on the pipeline 6, and increasing the pressure of the clamping piece 411 away from the bending position on the pipeline 6. Under the condition of ensuring that the total pressure basically does not change, the pressure distribution of each clamping piece 411 on the pipeline 6 is kept uniform, thereby being conducive to improving the quality of the bent pipeline.

[0064] The above only describes the preferred embodiments of the present application, and it should be noted that those skilled in the art can make some improvements and refinements without departing from the technical principles of the present application, and these improvements and refinements should also be considered as the protection scope of the present application.

Claims

1. A clamping device, characterized in that, include: A rotating assembly and a horizontal clamping table, the rotating assembly driving the clamping table to rotate; The clamping assembly is distributed on the same side of the rotation axis of the clamping table along a horizontal first direction. It includes a translation unit and a clamping unit. The translation unit drives the clamping unit to move along the first direction to clamp the pipe. In the clamped state, the axis of the pipe extends along a horizontal second direction that is perpendicular to the first direction. The axis of the pipe is spaced apart from the rotation axis of the clamping table. The translation unit includes: A single-acting hydraulic cylinder, distributed along a second direction, includes a cylinder barrel fixed to the clamping table and a piston assembly that seals through one end of the cylinder barrel and surrounds the cylinder barrel to form a rod chamber and a rodless chamber. The cylinder barrel has a built-in reset member that drives the piston assembly toward the oil port and has an air port communicating with the rod chamber. The switching valve has an oil supply valve port for connecting to the output end of a hydraulic pump, an oil discharge valve port for connecting to a hydraulic tank, and a connecting valve port that communicates with each oil port. The working modes include an oil supply mode, an oil discharge mode, and an oil isolation mode. In the oil supply mode, the oil supply valve port is connected to the connecting valve port and isolated from the oil discharge valve port. In the oil discharge mode, the connecting valve port is connected to the oil discharge valve port and isolated from the oil supply valve port. In the oil isolation mode, the oil supply valve port, the oil discharge valve port, and the connecting valve port are isolated from each other. The clamping unit includes a clamping mechanism corresponding to each of the single-acting hydraulic cylinders. The clamping mechanism includes a clamping plate and a pressing member. The clamping plate is a deformable metal sheet connected to the piston assembly through the pressing member. In its natural state, the clamping plate is integrally formed with an arc-shaped groove extending along the second direction. The inner diameter of the inner wall cross-section of the arc-shaped groove is the same as the outer diameter of the pipe.

2. The clamping device according to claim 1, characterized in that: The clamping unit further includes a guide plate that is coaxial with the arc groove and located on the side of the arc groove opposite to its own opening. The extrusion member includes an extrusion block connected to the piston assembly and an extrusion protrusion that slides radially through the guide plate along the arc groove and is located between the extrusion block and the clamping piece. The guide plate and the extrusion block slide relative to each other in a first direction and are limitedly connected.

3. The clamping device according to claim 2, characterized in that: The end of the extrusion protrusion adjacent to the extrusion block is provided with an elastic buffer pad, and the other end is hemispherical.

4. The clamping device according to claim 2, characterized in that: The clip is detachably connected to the guide plate.

5. The clamping device according to claim 4, characterized in that: The clip is connected to the guide plate via a magnetic connection structure, which includes two permanent magnets that attract each other magnetically, or a permanent magnet and a magnetic conductor that attract each other magnetically.

6. The clamping device according to any one of claims 1-5, characterized in that: The clip is a soft stainless steel sheet or a nickel-plated brass sheet with a thickness of 0.3-1mm.

7. The clamping device according to any one of claims 1-5, characterized in that: The switching valve includes: The valve housing is a hollow cylinder, and the oil supply valve port, the oil discharge valve port and the connecting valve port are all located on the outer circumferential edge of the valve housing. The valve core has an outer surface that is sealed and fitted to the inner wall of the valve housing and rotates within the valve housing about its own axis. The valve core has an L-shaped flow channel, the two ends of which extend to the circumferential outer edge of the valve core. An adjustment unit is disposed inside the valve core and drives the valve core to rotate.

8. A pipe bending machine, characterized in that, include: The clamping device as described in any one of claims 1-7; The wheel mold base is fixed on the clamping platform and has a wheel groove extending along a semi-circular trajectory on its outer circumferential edge. The rotation axis of the clamping platform passes through the center of the wheel groove extension trajectory. The inner wall cross-section of the wheel groove has the same shape and size as the inner wall cross-section of the arc groove. One end of the wheel groove is coaxially connected to the arc groove in one of the clamping components in the clamping state. The positioning component, located adjacent to the wheel mold base on the side away from the clamping device, includes a fixed mold base, a movable mold base, and a movable unit. The fixed mold base is fixedly installed, and the movable unit drives the movable mold base to close and separate from the fixed mold base. In the closed state, the fixed mold base and the movable mold base enclose each other to form a positioning channel that fits against the outer edge of the pipe's circumference. The pipe passes through the positioning channel at the end adjacent to the clamping device.

9. The pipe bending machine according to claim 8, characterized in that: The top surface of the fixed mold base is provided with a lower positioning groove with the groove opening facing upwards. The side of the movable mold base adjacent to the fixed mold base is provided with an upper positioning groove. The upper positioning groove is used to form a positioning channel with the lower positioning groove when the mold is closed. The movable mold base is rotatably connected to the fixed mold base and the rotation axis is consistent with the extension direction of the lower positioning groove.

10. A method for bending a pipe, characterized in that, Includes the following steps: S10. Preliminary preparation: Place the straight pipe on the fixed mold base, adjust the axial position of the pipe, and then control the movable mold base and the fixed mold base to close together through the movable unit to form a positioning channel that fits with the outer edge of the pipe in the circumferential direction, so that the position of the pipe to be bent is outside the positioning channel. S20, Clamping and positioning: At the end of the pipe away from the positioning channel where it is to be bent, the pipe is clamped and fixed by the interaction of the opposing clamping components. S30, Bending process: The clamping assembly is controlled to rotate to a preset angle by the rotating assembly. The rotation axis of the clamping assembly extends in the vertical direction and is spaced from the axis of the pipe. S40. Remove product: The clamping components separate from each other, and at the same time, the movable unit controls the movable mold base to separate from the fixed mold base so as to remove the processed pipe; In step S20, the clamping assembly includes a translation unit and a clamping unit. The translation unit drives the clamping unit to move along a first direction, which is parallel to the orientation of the clamping assembly. When clamping, the axis of the pipe is in a horizontal second direction. The translation unit includes: A single-acting hydraulic cylinder, distributed along a second direction, includes a cylinder barrel and a piston assembly that seals through one end of the cylinder barrel near a pipe and surrounds the cylinder barrel to form a rod chamber and a rodless chamber. The cylinder barrel has a built-in reset member that drives the piston assembly toward the oil port and has an air port communicating with the rod chamber. The switching valve has an oil supply valve port for connecting to the output end of a hydraulic pump, an oil discharge valve port for connecting to a hydraulic tank, and a connecting valve port that communicates with each oil port. The working modes include an oil supply mode, an oil discharge mode, and an oil isolation mode. In the oil supply mode, the oil supply valve port is connected to the connecting valve port and isolated from the oil discharge valve port. In the oil discharge mode, the connecting valve port is connected to the oil discharge valve port and isolated from the oil supply valve port. In the oil isolation mode, the oil supply valve port, the oil discharge valve port, and the connecting valve port are isolated from each other. The clamping unit includes a clamping mechanism corresponding to each of the single-acting hydraulic cylinders. The clamping mechanism includes a clamping plate and a pressing member. The clamping plate is a deformable metal sheet connected to the piston assembly through the pressing member. In its natural state, the clamping plate is integrally formed with an arc-shaped groove extending along the second direction. The inner diameter of the inner wall cross-section of the arc-shaped groove is the same as the outer diameter of the pipe.

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