A clamping device, a pipe bender and a pipe bending method

Abstract

This invention discloses a clamping device, a pipe bending machine, and a pipe bending method. The clamping device includes a rotating assembly and a clamping table. The clamping assembly, arranged opposite each other, includes a translation unit and a clamping unit. The translation unit includes a single-acting hydraulic cylinder, comprising a cylinder barrel and a piston assembly, with a built-in reset component and an air port in the cylinder barrel. A switching valve is provided, with operating modes including an oil supply mode, an oil discharge mode, and an oil separation mode. The clamping unit includes a clamping mechanism, which includes clamping plates and a pressing component. This clamping device, pipe bending machine, and pipe bending method achieve surface contact between the clamping plates and the pipe, increasing the pressure area and ensuring that the pressure is reduced under the action of clamping force to avoid indentation. During the pipe bending process, the rodless chambers corresponding to the hydraulic cylinders in the translation unit are interconnected, facilitating the interconnection of hydraulic oil between the rodless chambers to automatically adjust the clamping force of the clamping plates on the pipe. This ensures that the clamping force is uniform along the pipe axis near the bending position, thereby improving the quality of the pipe bending.

Description

Technical Field

[0001] This invention relates to the field of pipe bending technology, and in particular to a clamping device, a pipe bending machine, and a pipe bending method. Background Technology

[0002] The clamping die is an important component of a pipe bending machine. It is used to clamp and fix the pipe, and works with a rotating device to drive the clamping die to rotate, thus achieving the bending process of the pipe. To prevent slippage, the inner wall of the clamping die is usually densely covered with a grid of protrusions to increase roughness and thus increase friction. This makes it less likely for the pipe to slip within the die, ensuring the positioning accuracy and processing quality of the pipe, and ensuring that the shape of the bent pipe meets the design requirements.

[0003] While the grid-like protrusions on the inner wall of the mold can play a positive role, the protruding material is usually quite hard and has a rough surface. During clamping, excessive clamping force, especially when the pipe material is relatively soft, can lead to excessive pressure at the contact point between the pipe and the protrusions, resulting in abrasion marks during bending and affecting pipe quality. Furthermore, as the clamping device is used over time, the protrusions will also wear down, their surfaces becoming smoother, leading to a significant decrease in the clamping force on the pipe, affecting the clamping effect and thus reducing the quality of the bend. In addition, during bending, the pipe changes shape, and the pipe material near the bend undergoes greater plastic deformation, requiring greater resistance to change shape. Therefore, for... The protrusions on the clamping device near the bend require a greater clamping force to secure the pipe and prevent displacement or slippage during bending. However, in existing technology, the grid-like protrusions are usually of uniform height, making it difficult to adjust the clamping force according to the stress generated during pipe deformation. This results in the protrusions near the bend experiencing greater force and wear, while the protrusions further away from the bend experience less reaction force and wear. As usage time increases, the difference in wear between the two locations widens. Therefore, workers need to periodically replace the grid-like protrusions on the clamping device, even when the clamping effect of some protrusions is still reliable, leading to increased processing costs for the pipe bending machine.

[0004] Therefore, it is necessary to improve the clamping device for pipe bending machines in the existing technology. Summary of the Invention

[0005] The purpose of this invention is to overcome the defects in the prior art and provide a clamping device, a pipe bending machine, and a pipe bending method that avoids indentation, ensures uniform clamping force during pipe bending, improves pipe bending quality, and reduces replacement costs.

[0006] To solve the above-mentioned technical problems, the present invention provides a clamping device, comprising: 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.

[0007] Preferably, in order to further facilitate the clamping of the pipe during the turning process, the clamping unit further includes a guide plate 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.

[0008] Preferably, in order to ensure that one end of the extrusion protrusion makes full contact with the extrusion block, while reducing damage to the clamping plate at the other end and extending the service life of the clamping plate, an elastic buffer pad is provided at the end of the extrusion protrusion adjacent to the extrusion block, and the other end is hemispherical.

[0009] Preferably, in order to ensure the clamping quality of the pipe under long-term use, the clamping plate is detachably connected to the guide plate.

[0010] Preferably, in order to facilitate the detachable connection of the clip, the clip is connected to the guide plate through a magnetic connection structure, the magnetic connection structure including two permanent magnets that attract each other by magnetic force, or a permanent magnet and a magnetic conductor that attract 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 0.3-1mm.

[0012] Preferably, to facilitate control of the connection between the unidirectional hydraulic cylinder barrel and the hydraulic pump and hydraulic tank, 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.

[0013] To address the aforementioned technical problems, the present invention also provides a pipe bending machine, comprising: The clamping device described in any of the above technical solutions; 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.

[0014] Preferably, in order to facilitate axial positioning of the pipeline, the top surface of the fixed mold base is provided with a lower positioning groove with the groove opening facing upwards, and 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 molded together. 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.

[0015] To address the aforementioned technical problems, the present invention also provides a pipe bending method, comprising 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 apart from the axis of the pipe. S40. Product Removal: 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.

[0016] In summary, compared with the prior art, the clamping device, pipe bending machine, and pipe bending method of the present invention achieve surface contact between the clamping plates and the pipe, increasing the pressure area and ensuring that the pressure is reduced under the action of clamping force to avoid indentation. During the pipe bending process, the rodless chambers corresponding to each hydraulic cylinder in the translation unit are interconnected, which facilitates the interconnection of hydraulic oil between the rodless chambers to automatically adjust the clamping force of the clamping plates on the pipe, so that the clamping force is uniform along the pipe axis near the bending position, thereby improving the quality of pipe bending. Attached Figure Description

[0017] Figure 1 This is a schematic diagram of the pipe bending machine of the present invention when placing the pipe; Figure 2 This is a schematic diagram of the structure of the pipe bending machine of the present invention for adjusting the axial position after placing the pipe; Figure 3 This is a schematic diagram of the radial positioning of the pipe bending machine of the present invention; Figure 4 This is a schematic diagram of the pipe bending machine clamping and positioning of the present invention; Figure 5 This is a schematic diagram of the connection structure between the frame and the positioning component of the present invention; Figure 6 yes Figure 5 An explosion diagram; Figure 7 This is a schematic diagram of the connection structure between the frame and the positioning component of the present invention from another perspective; Figure 8 This is a schematic diagram of the frame structure of the present invention; Figure 9 This is a schematic diagram of the clamping device of the present invention; Figure 10 yes Figure 9 An explosion diagram; Figure 11 This is a schematic diagram of the clamping assembly of the present invention; Figure 12 yes Figure 11 An explosion diagram; Figure 13 This is a schematic diagram of the switching valve of the present invention; Figure 14 yes Figure 13 An explosion diagram; Figure 15 yes Figure 14 A schematic diagram of the cross-sectional structure; Figure 16 This is a schematic diagram of the structure of the single-acting hydraulic cylinder of the present invention; Figure 17 yes Figure 16 An explosion diagram; Figure 18This is a schematic diagram of the clamping unit of the present invention; Figure 19 yes Figure 18 An explosion diagram; Figure 20 yes Figure 18 A schematic diagram of the cross-sectional structure; In the diagram: 1. Rotating assembly; 11. Gear; 12. Rack; 13. Telescopic unit; 131. Telescopic motor; 132. Telescopic screw; 133. Telescopic sleeve; 2. Clamping table; 21. Wheel mold base; 22. Support unit; 221. Foot; 222. Support plate; 223. Support bearing; 224. Turntable; 23. Support leg; 24. Caster wheel; 25. Concentric cam shaft; 3. Translation unit; 31. Single-acting hydraulic cylinder; 32. Cylinder barrel; 321. Cylinder body; 322. Cylinder cover; 323. 3231. Air inlet; 3232. Filter element; 324. Oil inlet; 335. Piston assembly; 336. Hydraulic piston; 337. Piston rod; 338. Connecting plate; 339. Connecting bolt; 300. Switching valve; 341. Valve barrel; 3412. Oil supply valve port; 3413. Oil discharge valve port; 3414. Connecting valve port; 342. Valve cover; 35. Valve core; 351. Flow channel; 36. Adjusting unit; 37. Connecting shell; 371. Flow collector; 372. Flow divider; 38. Electromagnet; 4. Clamping unit; 41. Clamping mechanism; 411, clamping plate; 4111, positioning cam; 4112, magnetic conductor; 412, extrusion block; 4122, slide groove; 4123, slide rail; 4124, notch; 413, extrusion cam; 414, buffer pad; 5, guide plate; 51, permanent magnet; 52, arc plate; 521, slide opening; 522, positioning opening; 53, sliding plate; 54, limiting tube; 55, fixing bolt; 6, pipe; 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. Raised strip; 723. Upper rotating seat; 73. Movable unit; 731. Movable motor; 732. Movable lead screw; 733. Movable bushing; 734. Movable block; 735. Vertical bar; 7351. Strip-shaped opening; 736. Rotating tube; 737. Limit bolt; 8. Frame; 81. Support platform; 82. Column; 83. Support roller; 84. Moving motor; 85. Moving roller; 86. Guide frame; 87. Guide rail. Detailed Implementation

[0018] The specific embodiments of the present invention will be further described below with reference to the accompanying drawings and examples. The following examples are only used to more clearly illustrate the technical solutions of the present invention and should not be construed as limiting the scope of protection of the present invention.

[0019] like Figures 9-20 As shown, a clamping device of the present invention includes: Rotating assembly 1 and horizontal clamping table 2, rotating assembly 1 drives clamping table 2 to rotate; The clamping assembly is distributed on the same side of the rotation axis of the clamping table 2 along a horizontal first direction. It includes 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 pipe 6. In the clamped state, the axis of the pipe 6 extends along a horizontal and perpendicular second direction. There is a gap between the axis of the pipe 6 and the rotation axis of the clamping table 2. Translation unit 3 includes: A single-acting hydraulic cylinder 31 is distributed along the second direction and includes a cylinder barrel 32 fixed on a clamping table 2 and a piston assembly 33 that seals and penetrates one end of the cylinder barrel 32 and surrounds the cylinder barrel 32 to form a rod chamber and a rodless chamber. The cylinder barrel 32 has a reset member built in it to drive the piston assembly 33 toward the oil port 324 and has an air port 323 that communicates with the rod chamber. The switching valve 34 has an oil supply valve port 3411 for connecting to the output end of the hydraulic pump, an oil discharge valve port 3412 for connecting to the hydraulic tank, and a connecting valve port 3413 connected to each oil port 324. The working modes include oil supply mode, oil discharge mode, and oil isolation mode. In the oil supply mode, the oil supply valve port 3411 is connected to the connecting valve port 3413 and isolated from the oil discharge valve port 3412. In the oil discharge mode, the connecting valve port 3413 is connected to the oil discharge valve port 3412 and isolated from the oil supply valve port 3411. In the oil isolation mode, the oil supply valve port 3411, the oil discharge valve port 3412, and the connecting valve port 3413 are isolated from each other. The clamping unit 4 includes a clamping mechanism 41 corresponding to the single-acting hydraulic cylinder 31. The clamping mechanism 41 includes a clamping piece 411 and a pressing member. The clamping piece 411 is a deformable metal sheet connected to the piston assembly 33 through the pressing member. In its natural state, the clamping piece 411 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 6.

[0020] It should be noted that, in this invention, the hydraulic pump and hydraulic tank connected to the switching valve 34 are specifically connected as follows: the input end of the hydraulic pump is connected to the inner cavity of the hydraulic tank, the drain valve port 3412 is connected to the inner cavity of the hydraulic tank, and the hydraulic tank is used to store hydraulic oil.

[0021] In this clamping device, the clamping components facing each other cooperate to clamp the pipe 6, thereby achieving the clamping effect on the pipe 6. The clamping components mainly include a translation unit 3 and a clamping unit 4. The translation unit 3 drives the clamping unit 4 to move. The clamping units 4 on both sides cooperate to squeeze and fix the pipe 6. The clamping plates 411 in the translation unit 3 and the clamping unit 4 correspond one-to-one and are driven to connect. The translation unit 3 also includes a switching valve 34. According to different usage conditions, the switching valve 34 is in different working modes, as described below.

[0022] First, when the pipe 6 to be bent is placed between the opposing clamping assemblies, the switching valves 34 on both sides are in oil supply mode. In this mode, the hydraulic pump draws hydraulic oil from the hydraulic tank and delivers it to the rodless chamber of each single-acting hydraulic cylinder 31 through the switching valves 34, causing the piston assembly 33 to extend outward and move. The clamping member drives the clamping plate 411 to approach the pipe 6, and finally the clamping plate 411 abuts against the circumferential outer edge of the pipe 6. Since the clamping plate 411 is integrally formed with an annular groove in its natural state, and the inner diameter of the annular groove is consistent with the outer diameter of the pipe 6, the pressure of the hydraulic oil is finally transmitted to the piston assembly 33, and then the piston assembly 33 applies pressure to the clamping plate 411, so that the clamping plate 411 locks and fixes the pipe 6. Since the clamping plate 411 and the pipe 6 do not contact each other, the contact area between the two is guaranteed, the pressure on the pipe 6 is reduced, and indentations are avoided during the compression and fixing process.

[0023] After the clamping plate 411 locks and fixes the pipe 6, the switching valve 34 is then 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 isolated from each other. In this way, there is no more hydraulic oil flowing between the hydraulic tank and the rodless chamber of the cylinder 32. In the clamping assemblies on both sides, the rodless chambers of each single-acting hydraulic cylinder 31 are connected to each other, the total amount of hydraulic oil is constant, and the sum of the squeezing forces of each clamping mechanism 41 on the pipe 6 in each clamping assembly is fixed.

[0024] In this state, the rotating component 1 is activated, driving the clamping table 2 to rotate, which in turn causes the clamping component on the clamping table 2 to rotate. Since the clamping component has already clamped the pipe 6, the clamped part of the pipe 6 is relatively fixedly connected to the clamping component and the clamping table 2, thereby driving the clamped position of the pipe 6 to rotate, thus realizing the bending process of the pipe 6.

[0025] During the bending process of pipe 6, the shape of the bent section of pipe 6 changes, causing stress at and around the bending location. Specifically, the closer to the bending location, the stronger the stress, and the greater the reaction extrusion force on the corresponding clamp 411. Conversely, the farther away from the bending location, the weaker the stress, and the smaller the reaction extrusion force on the corresponding clamp 411. In the same side extrusion assembly, the switching valve 34 is in oil-separated mode. In this mode, the rodless chambers of the cylinder 32 of the single-acting hydraulic cylinder 31 are interconnected. The clamp 411 can transmit pressure to the piston assembly 33 of the single-acting hydraulic cylinder 31 through the extrusion component, thus reducing stress at locations of higher stress in pipe 6. The hydraulic oil in the rodless chamber of the corresponding single-acting hydraulic cylinder 31 flows to the hydraulic oil in the rodless chamber of the single-acting hydraulic cylinder 31 corresponding to the position of lower stress in the pipe 6. That is, the clamping components on both sides can gradually reduce the extrusion pressure near the bend of the pipe 6 while increasing the pressure away from the bend of the pipe 6, according to the progress of the pipe bend, while ensuring that the total amount of extrusion and clamping force on both sides remains constant. This ensures the extrusion and clamping effect on the pipe 6. Furthermore, the clamp 411 is a deformable metal sheet that can adapt to the shape change of the pipe 6 through slight deformation, ensuring the surface-to-surface fit between the clamp 411 and the pipe 6, reducing pressure, and further preventing the generation of pressure.

[0026] Furthermore, through the above design, during the pipe bending process, it can be ensured that the squeezing force of the clamps 411 on the pipe 6 is uniform and consistent along the axial direction of the pipe 6 near the bending position. This ensures that the degree of damage to the clamps 411 is basically consistent, avoiding the clamps 411 near the bending position from being subjected to greater force and more easily worn and deformed. Thus, by adjusting the working mode to the oil-separating mode by the switching valve 34, the rodless chambers in the cylinder barrel 32 of each single-acting hydraulic cylinder 31 are connected, facilitating the flow of hydraulic oil. This allows the clamps 411 to promote the flow of hydraulic oil according to the pressure applied to the pipe 6 during bending and deformation, thereby ensuring that the squeezing force and wear degree of the clamps 411 on the pipe 6 are uniform and consistent. This achieves automatic dynamic adjustment of the squeezing force along the axial direction of the pipe 6, which in turn helps to extend the service life of the clamps 411.

[0027] Finally, after the pipe bend is completed, the switching valve 34 is adjusted to the oil discharge mode, so that the hydraulic oil in the rodless chamber of the single-acting hydraulic cylinder 31 in each clamping assembly is discharged, causing the piston assembly 33 to retract and drive the clamping plates 411 on both sides to move away from each other, making it easier to remove the pipe after the bend is completed.

[0028] Specifically, in this invention, the clamping platform 2 and the rotating assembly 1 of the clamping device are structured as follows: Figure 9 and Figure 10As shown, the clamping table 2 is horizontally positioned and comprises two parts. The first part is a rectangular plate, the length of which is parallel to the first direction and the width of which is parallel to the second direction. The second part is a semi-circular plate on the same horizontal plane as the rectangular plate. The semi-circular plate is integrally formed on the long side of the rectangular plate and is located on one side of the line connecting the midpoints of the two long sides of the rectangular plate. In the clamped state, the pipe 6 is parallel to the line connecting the midpoints of the two long sides of the rectangular plate and is located on the same vertical plane. Two clamping components are provided and distributed on the line connecting the midpoints of the two long sides of the rectangular plate. The rotation axis of the clamping table 2 coincides with the axis of the semi-circular plate. In this way, it is ensured that there is a gap between the axis of the pipe 6 and the rotation axis of the clamping table 2 during the pipe bending operation.

[0029] A support leg 23 extending vertically is fixed at the bottom of the rectangular plate. A caster wheel 24 is provided at the bottom of the support leg 23. The caster wheel 24 is connected to the ground to facilitate the rolling of the caster wheel 24 on the ground. A concentric convex shaft 25 with the same axis as the semi-circular plate is also fixed at the bottom of the clamping platform 2. The concentric convex shaft 25 is connected to the support unit 22. In this way, the clamping platform 2 can rotate stably with the axis of the semi-circular plate as the center line.

[0030] Specifically, the support unit 22 includes a turntable 224, a support bearing 223, a support plate 222, and a base 221 arranged sequentially from bottom to top. The turntable 224 is coaxially fixed to the bottom end of the concentric convex shaft 25. The top of the inner ring of the support bearing 223 is fixedly connected to the bottom surface of the turntable 224, and the outer ring is fixed to the bottom surface of the support plate 222. The top of the base 221 is fixedly connected to the support plate 222, and the bottom end is connected to the ground. This facilitates the smooth rotation of the clamping table 2 after the rotating component 1 is in operation.

[0031] The rotating assembly 1 includes a gear 11, a rack 12, and a telescopic unit 13. Specifically, the gear 11 is annular and fixedly sleeved on the concentric convex shaft 25. The rack 12 meshes with the gear 11 and its length direction is parallel to the width direction of the rectangular plate, that is, the first direction. The telescopic unit 13 drives the rack 12 to move along its own length direction, thereby driving the gear 11 to rotate, so that the concentric convex shaft 25 drives the clamping platform 2 above it to rotate around the axis of the semi-circular plate.

[0032] More specifically, the telescopic unit 13 includes a telescopic motor 131, a telescopic screw 132, and a telescopic sleeve 133. The telescopic motor 131 is fixedly installed, and its output end is axially parallel to the length direction of the rack 12 and fixedly connected to the telescopic screw 132. The telescopic sleeve 133 is threadedly connected to the telescopic screw 132 and fixed above the rack 12. Thus, when the telescopic motor 131 runs, it drives the telescopic screw 132 to rotate, and through the thread, it acts on the telescopic sleeve 133, causing the telescopic sleeve 133 to drive the rack 12 to translate along the first direction, thereby realizing the rotation of the clamping table 2.

[0033] The single-acting hydraulic cylinder 31 transmits pressure through the oil inside it, and its specific structure is as follows: Figure 12 , Figure 16 and Figure 17 As shown, in the single-acting hydraulic cylinder 31, the cylinder barrel 32 includes a cylinder body 321 and a cylinder cover 322 fixedly connected. The cylinder body 321 is fixed above the clamping table 2, and its axis is parallel to the second direction. The cylinder cover 322 is fixed to one end of the cylinder body 321 adjacent to the clamping plate 411. The other end of the cylinder body 321 is closed. The bottom of the cylinder body 321 is 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 chamber or to introduce hydraulic oil into the rodless chamber. The oil is extruded, and the air port 323 facilitates the connection between the rod chamber and the outside. The air port 323 is equipped with a filter element 3231, which includes a filter tube threaded to the air port 323 and a filter screen fixed to the end of the filter tube. This prevents external impurities from entering the cylinder 32 during the air permeation process, thus preventing wear between the inner wall of the cylinder 32 and the piston assembly 33 from causing a decrease in sealing performance. Furthermore, the filter element 3231 is threaded to the air port 323, making it convenient to replace and maintain the filter element 3231.

[0034] The piston assembly 33 includes a piston rod 332, a connecting plate 333 integrally connected to both ends of the piston rod 332, and a hydraulic piston 331. The circumferential outer edge of the hydraulic piston 331 is sealed to the circumferential inner wall of the cylinder 321 and slides axially between the air port 323 and the oil port 324 along the cylinder 321. The piston rod 332 sealably penetrates the cylinder cover 322. The connecting plate 333 is connected to the extruder. Thus, the piston assembly 33 moves by the change of hydraulic oil in the rodless chamber inside the cylinder 32, thereby driving the extruder to move.

[0035] The single-acting hydraulic cylinder 31 is also equipped with a reset component, which is used to push the piston assembly 33 to a position close to the oil port 324 and discharge the hydraulic oil in the rodless chamber through the oil port 324. In this invention, the reset component includes two electromagnets 38 with magnetic repulsion, which are respectively fixed on the cylinder cover 322 and the two sides facing the hydraulic piston 331.

[0036] In existing technologies, return springs are commonly used as reset components. However, return springs are prone to aging after repeated use, affecting the reset force and making it difficult to precisely control their elasticity. This invention uses two magnetically repulsive electromagnets 38 to form the reset component. When hydraulic oil needs to be extruded from the rodless chamber, power is supplied to the two electromagnets 38, generating a magnetically repulsive magnetic field that pushes the piston assembly 33 back. Therefore, using two electromagnets 38 as the reset component, compared to using a return spring, offers several advantages: First, it avoids mechanical wear of the spring, extending the lifespan of the reset component. Second, the reset force can be flexibly adjusted. The elastic force of a return spring is determined by its elastic coefficient and elastic deformation, and the elastic coefficient changes with usage time, making precise control impossible. The magnetic repulsive force, on the other hand, can be precisely controlled by adjusting the current to the two electromagnets 38. Third, return springs are prone to loosening or breakage, while electromagnets 38 only require their coils to function properly to achieve stable reset of the piston assembly 33, resulting in a more reliable reset component composed of electromagnets 38.

[0037] To facilitate flexible switching of the switching valve 34 between three operating modes—oil supply mode, oil discharge mode, and oil separation mode—in this invention, the switching valve 34 includes: The valve housing is a hollow cylinder, and the oil supply valve port 3411, the oil discharge valve port 3412 and the connecting valve port 3413 are all located on the outer circumferential edge of the valve housing. The valve core 35 has an outer surface that is sealed and fitted to the inner wall of the valve housing and rotates around its own axis within the valve housing. The valve core 35 has an L-shaped flow channel 351, with both ends of the flow channel 351 extending to the circumferential outer edge of the valve core 35. The regulating unit 36 ​​is disposed inside the valve core 35 and drives the valve core 35 to rotate.

[0038] With the above design, the valve core 35 inside the valve housing is rotated by the adjustment unit 36, and the position of the flow channel 351 on the valve core 35 is adjusted, thereby realizing the switching of three working modes. Specifically, when the two ends of the flow channel 351 are respectively connected to 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 to 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] More specifically, such as Figures 11-15As shown, the valve housing includes a valve barrel 341 with an open top and a cylindrical shape, and a valve cover 342 fixedly located on the top of the valve barrel 341. An oil supply valve port 3411, a connecting valve port 3413, and an oil discharge valve port 3412 are sequentially distributed along the outer periphery of the valve barrel 341. The oil supply valve port 3411 and the oil discharge valve port 3412 are arranged coaxially and back-to-back. The axis of the connecting valve port 3413 is perpendicular to the axis of the oil supply valve port 3411. The adjusting unit 36 ​​includes a stepper motor fixed to the valve cover 342. The stepper motor is downward-facing, and its output shaft seal passes through the valve cover 342 and is fixedly connected coaxially to the valve core 35. The step angle of the stepper motor is 90°. In the initial position, the two ends of the flow channel 351 are respectively connected to the oil supply valve port 3411 and the connecting valve port 3413, meaning the switching valve 34 is in oil supply mode. Figure 15 As shown, the valve core 35 rotates counterclockwise.

[0040] With the above design, in the initial state, the switching valve 34 is in the oil supply mode. The hydraulic pump can draw hydraulic oil from the hydraulic tank and deliver it to the oil supply valve port 3411. The hydraulic oil is discharged from the connecting valve port 3413 through the flow channel 351 and enters the rodless chamber in the cylinder barrel 32 of the single-acting hydraulic cylinder 31, pushing the piston assembly 33 to move outward. When the stepper motor drives the valve core 35 to rotate once and then once more, after these 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, and the oil supply valve port 3411, the oil discharge valve port 3412, and the connecting valve port 3413 are blocked. The hydraulic oil in the rodless chamber of cylinder 32 is fixed due to the isolation between the two sides. When the stepper motor drives the valve core 35 to rotate for the fourth time, the two ends of the flow channel 351 are connected to the oil supply valve port 3411 and the connecting valve port 3413 respectively. The reset component is activated, pushing the piston assembly 33 towards the oil port 324, causing the hydraulic oil in the rod chamber to be squeezed out of the oil port 324, enter the flow channel 351 through the connecting valve port 3413, and then be discharged through the oil discharge valve port 3412 into the hydraulic tank. After that, the stepper motor runs again, so that the two ends of the flow channel 351 are connected to the oil supply valve port 3411 and the connecting valve port 3413 respectively, and the switching valve 34 is in the oil supply mode. In this way, when the stepper motor of the regulating unit 36 ​​rotates, the switching valve 34 can realize the cyclic adjustment of the three working modes: "oil supply mode → oil separation mode → oil separation mode → oil supply mode".

[0041] Furthermore, such as Figure 11 and Figure 12As shown, the translation unit 3 also includes a hollow connecting shell 37. The length direction of the connecting shell 37 is parallel to the second direction. The connecting shell 37 is fixed between each cylinder 32 and the valve shell. Specifically, the side wall of the connecting shell 37 is provided with a flow collecting port 371, and the top wall is provided with a flow dividing port 372. The flow collecting port 371 is fixedly connected to the connecting valve port 3413, and the flow dividing port 372 is fixedly connected to the oil port 324 of each cylinder 32. In this way, the mutual communication between the rodless chambers of each cylinder 32 is realized, which facilitates the flow of hydraulic oil between the rodless chambers during the bending process of the pipeline 6 under the influence of stress changes, and ensures that the fastening force on each part of the pipeline 6 tends to be uniform.

[0042] A further improvement is that the clip 411 is a soft stainless steel sheet or a nickel-plated brass sheet with a thickness of 0.3-1mm.

[0043] With this design, on the one hand, it can ensure that the clamp 411 can deform to a certain extent after being subjected to changes in compressive pressure, that is, it has a certain degree of flexibility. On the other hand, it is not easy to undergo permanent deformation after being subjected to compressive pressure, and the surface is easy to polish. The clamp 411 is processed to a roughness of less than 0.8um to avoid scratching the pipe 6 and to ensure that there is sufficient contact pressure area between it and the pipe 6 to reduce pressure.

[0044] A further improvement is that the clamping unit 4 also includes a guide plate 5 that is coaxial with the arc groove and located on the side of the arc groove opposite to its own opening. The extrusion component includes an extrusion block 412 connected to the piston assembly 33 and an extrusion protrusion 413 that slides radially through the guide plate 5 along the arc groove and is 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 in a first direction and are limitedly connected. An elastic buffer pad 414 is provided at one end of the extrusion protrusion 413 adjacent to the extrusion block 412, and the other end is hemispherical.

[0045] Specifically, such as Figure 11 , Figure 12 , Figures 18-20As shown, in this invention, five extrusion blocks 412 are arranged sequentially along the second direction in the clamping mechanism 41, and five corresponding single-acting hydraulic cylinders 31 are also arranged (of course, the number can be flexibly adjusted). Adjacent extrusion blocks 412 are connected in sequence, and notches 4124 are provided on both sides of the extrusion block 412. One side of the extrusion block 412 is fixedly connected to the connecting plate 333 by connecting bolts 334, and the other side is an arc surface. The arc surface is coaxial with the arc groove and is densely covered with extrusion protrusions 413. The axial direction of the extrusion protrusions 413 is parallel to the radial direction of the arc surface. The bottom end of the extrusion block 412 is provided with a sliding groove 4122 extending along the first direction. The sliding groove 4122 is a through groove. The clamping table 2 is fixed with a slide rail 4123 corresponding to the extrusion block 412. The sliding groove 4122 and the slide rail 4123 slide in cooperation to ensure that the extrusion block 412 can move smoothly along the first direction when the single-acting hydraulic cylinder 31 is running.

[0046] The guide plate 5 comprises 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 semi-circular, and its inner diameter is between the outer diameter of the clamping piece 411 and the inner diameter of the arc surface of the extrusion block 412. The arc-shaped plate 52 is densely covered with sliding openings 521, through which the extrusion protrusion 413 slides in a sealed manner along its own axial direction. The second part is a sliding plate 53 integrally formed at both ends of the arc-shaped plate 52 and located on the side opposite to the clamping piece 411. The sliding plates 53 at both ends slide and engage with the notches 4124 on the outer side of the extrusion block 412 at the end position and pass through 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 its two ends are respectively connected to the two sliding plates. The guide plate 5 and the extrusion block 412 are fitted together. The limiting tube 54 is located on the side of the extrusion block 412 opposite to the clamping plate 411 and its two ends are fixedly connected to the two sliding plates 53 by two fixing bolts 55 respectively. In this way, the guide plate 5 and the extrusion block 412 are slidably limited in the first direction. At the same time, the extrusion protrusion 413 is limited in the radial direction of the arc groove to the guide plate 5. The side of the extrusion protrusion 413 adjacent to the extrusion block 412 has an elastic buffer pad 414. The buffer pad 414 is preferably a rubber pad with an outer diameter larger than the inner diameter of the sliding opening 521. On the one hand, it prevents the extrusion protrusion 413 from disengaging from the sliding opening 521. On the other hand, it ensures sufficient contact area between the extrusion protrusion 413 and the arc surface of the extrusion block 412, and avoids the extrusion protrusion 413 from breaking and being damaged during the extrusion process due to being too thin.

[0047] With the above structure, the single-acting hydraulic cylinder 31 drives the extrusion block 412 to move along the length of the slide rail 4123, acting on the extrusion protrusion 413. The extrusion protrusion 413 acts on the clamping plate 411, causing the clamping plate 411 to move closer to the pipe 6. Finally, the clamping plate 411 abuts against the pipe 6. Hydraulic oil continues to be input into the rod chamber of the cylinder 32 to increase the hydraulic pressure, causing the extrusion block 412 to continue moving. During the movement, the buffer pad 414 acts on the extrusion protrusion 413, causing the densely packed extrusion protrusions 413 to move along their own length direction, that is, radially closer to the axis of the pipe 6, extruding the clamping plate 411. The clamping plate 411 achieves surface contact to reduce pressure while increasing the extrusion fixing force, preventing indentations from appearing on the surface of the pipe 6. Then, the switching valve 34 is adjusted to the oil-separated state to ensure that each extrusion block 412 exerts an extrusion fixing force on the clamping plate 411 through the extrusion component, thereby ensuring the extrusion fixing force of the clamping plate 411 on the pipe 6. As the rotating assembly 1 moves, the shape of the pipe 6 changes, causing stress near the bend. The intensity of this stress reacts on the clamping plate 411. At locations with higher stress, this stress tends to push the extrusion protrusion 413 away from the axis of the pipe 6. This allows the extrusion protrusion 413 to react on the extrusion block 412, which in turn acts on the piston assembly 33. Consequently, some of the hydraulic oil in the rodless chamber of the cylinder 32 near the bend flows through the connecting shell 37 into the rodless chamber of the cylinder 32 away from the bend. This automatically adjusts the extrusion and fixing force of each single-acting hydraulic cylinder 31. As the bend progresses, the extrusion and fixing force of the clamping plate 411 near the bend decreases, while the extrusion and fixing force of the clamping plate 411 away from the bend increases, ensuring that the extrusion and fixing force becomes more uniform and consistent, thereby improving the quality of the bend.

[0048] The end of the extrusion protrusion 413 near the clamping piece 411 is hemispherical, which keeps the extrusion surface of the extrusion protrusion 413 rounded and avoids it being too sharp and causing the clamping piece 411 to crack and be damaged.

[0049] A further improvement is that the clamping plate 411 is detachably connected to the guide plate 5. Since the clamping plate 411 bears the pressure of the extrusion protrusion 413 and the pipe 6, the detachable connection facilitates the replacement of worn clamping plates 411, thereby ensuring the long-term stable clamping force of the clamping device.

[0050] A further improvement is that the clip 411 is connected to the guide plate 5 through a magnetic connection structure, which includes two permanent magnets 51 that attract each other through magnetic force, or permanent magnets 51 and a magnetic conductor 4112 that attract each other through magnetic force.

[0051] Specifically, such as Figure 12 and Figure 19As shown, permanent magnets 51 extending along the first direction are fixed at the upper and lower ends of the arc plate 52. The permanent magnets 51 are strips made of magnets. Magnetic conductors 4112 extending along the first direction are fixed at the upper and lower ends of the clamping piece 411 on the side facing away from the arc groove. The magnetic conductors 4112 are strips supported by iron. Through the magnetic attraction between the permanent magnets 51 and the magnetic conductors 4112, the clamping piece 411 can be quickly installed on the inner side of the guide plate 5. In addition, a positioning convex shaft 4111 extending radially is integrally formed on the side of the clamping piece 411 facing away from the arc groove, and a positioning opening 522 extending radially is integrally formed on the arc plate 52. The positioning convex shaft 4111 and the positioning opening 522 correspond one-to-one and are clearance-fitted to ensure that the clamping piece 411 is accurately installed on the inner side of the guide plate 5, avoiding axial displacement of the clamping piece 411. This facilitates convenient and high-precision loading and unloading of the clamping piece 411.

[0052] Based on the above-mentioned clamping device, the present invention also discloses a pipe bending machine, such as... Figures 1-20 As shown, the pipe bending machine includes The aforementioned clamping device; The wheel mold base 21 is fixed on the clamping table 2 and has a wheel groove extending along a semi-circular trajectory on its outer circumferential edge. The rotation axis of the clamping table 2 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 connected to the arc groove in one of the clamping components in the clamping state along the same axis. The positioning component 7 is located adjacent to the side of the wheel mold base 21 away from the clamping device. It includes a fixed mold base 71, a movable mold base 72, and a movable unit 73. The fixed mold base 71 is fixedly installed. The movable unit 73 drives the movable mold base 72 to close and separate from the fixed mold base 71. In the closed state, the fixed mold base 71 and the movable mold base 72 form a positioning channel that fits against the outer edge of the pipe 6. The pipe 6 passes through the positioning channel and is adjacent to the clamping device.

[0053] Specifically, the wheel mold base 21 is fixed directly above the semi-circular plate of the clamping table 2, and the projection of the wheel mold base 21 on the horizontal plane is a semi-circle. The rotation axis of the clamping table 2 passes through the center of the semi-circular projection, and one side of the semi-circular projection is parallel to the second direction.

[0054] Positioning component 7 is mounted on frame 8. Frame 8 includes a horizontal support platform 81. The length and width directions of support platform 81 are parallel to the second and first directions, respectively. Downward-extending support columns 82 are fixed at the four corners of support platform 81. Telescopic motor 131 is fixed to the bottom surface of support platform 81. A guide frame 86 extending along the second direction is also fixed to the bottom surface of support platform 81. Figure 8 As shown, the outer circumferential edge of the telescopic sleeve 133 is sealed and fitted with the inner circumferential wall of the guide frame 86 to achieve smooth movement of the telescopic sleeve 133 along a direction parallel to the second direction.

[0055] A further improvement is that the top surface of the fixed mold base 71 is provided with a lower positioning groove 711, with the groove opening of the lower positioning groove 711 facing upwards. The side of the movable mold base 72 adjacent to the fixed mold base 71 is provided with an upper positioning groove 721. The upper positioning groove 721 is used to form a positioning channel with the lower positioning groove 711 when the mold is closed. The movable mold base 72 is rotatably connected to the fixed mold base 71, and the rotation axis is consistent with the extension direction of the lower positioning groove 711.

[0056] The movable mold base 72 is driven to move by the movable unit 73, realizing the mold closing and mold opening with the fixed mold base 71. In the mold opening state, it is convenient to place the straight pipe 6 to be processed into the lower positioning groove 711, or to remove the processed pipe 6 from the fixed mold base 71. In the mold closing state, the lower positioning groove 711 of the fixed mold base 71 and the upper positioning groove 721 of the movable mold base 72 form a positioning channel, which can radially position the pipe 6 and prevent the pipe 6 from radially shifting. In this way, it is convenient for the clamping device to perform pipe bending operation after clamping the radially fixed pipe 6.

[0057] like Figures 5-6 As shown, the fixed mold base 71 is a lower mold base fixed on the support platform 81 and extending along the second direction. The movable mold base 72 is an upper mold base rotatably connected to the fixed mold base 71 and extending along the second direction. The lower positioning groove 711 and the upper positioning groove 721 are both through grooves with a semi-circular cross-section and an inner diameter consistent with the outer diameter of the pipe 6. Two lower rotating seats 712 distributed along the second direction are provided on one side of the fixed mold base 71. An upper rotating seat 723 is provided on the same side of the movable mold base 72. The upper rotating seat 723 fits between the two lower rotating seats 712. The lower rotating seat 712 is threadedly connected to a rotating bolt 713. The rotating bolt 713 includes a screw part and a smooth rod part integrally connected on the coaxial center line. The screw part is threadedly connected to the lower rotating seat 712. The upper rotating seat 723 is sealed and sleeved outside the smooth rod part. In this way, the movable mold base 72 and the fixed mold base 71 are rotatably connected.

[0058] The upper rotating seat 723 has a protruding strip 722 fixed on its top surface, opposite to the upper positioning groove 721. One end of the protruding strip 722 is located above the upper rotating seat 723 and the lower rotating seat 712. The movable unit 73 includes a movable motor 731, a movable lead screw 732, a movable bushing 733, a movable block 734, a vertical bar 735, a rotating tube 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 bushing 733 are both fixed above the support platform 81. The movable motor 731 is driven and connected to one end of the movable lead screw 732. The other end of the movable lead screw 732 is sealed and fitted to the inner wall of the movable bushing 733. The movable block 734 is threadedly connected to the movable lead screw 732. The support platform 81 is fixed with a vertical bar 722. A guide rail 87 extends in one direction. A movable block 734 slides with the guide rail 87. Two vertical bars 735 are provided and fixed above the movable block 734. The two vertical bars 735 are attached to both sides of the protrusion 722. A strip-shaped opening 7351 extending vertically is provided on the vertical bar 735. A rotating tube 736 passes through the strip-shaped opening 7351 and seals through the end of the protrusion 722 located above the lower rotating seat 712 and the upper rotating seat 723. The outer diameter of the rotating tube 736 is the same as the width of the strip-shaped opening 7351. Limiting bolts 737 are threaded to both ends of the rotating tube 736. The cap of the limiting bolt 737 is attached to the side of the vertical bar 735 facing away from the protrusion 722, and the outer diameter of the cap is larger than the width of the strip-shaped opening 7351 to prevent the rotating tube 736 from detaching from the vertical bar 735 and the protrusion 722.

[0059] After adopting the above structure, the movable motor 731 starts, driving the movable lead screw 732 to rotate around its own axis under the guidance of the movable bushing 733. This rotation acts on the movable block 734 through the thread, causing the movable block 734 and the vertical bar 735 to move along the second direction. This, in turn, moves the rotating tube 736, changing the position of the protrusion 722. This, in turn, causes the movable mold base 72 to rotate around the axis of the rotating bolt 713. When the movable mold base 72 rotates upward, it separates from the fixed mold base 71. When the movable mold base 72 rotates downward until the upper positioning groove 721 and the lower positioning groove 711 are on the same axis, the movable mold base 72 and the fixed mold base 71 close, forming a positioning channel for axial positioning of the pipe 6. After axial positioning of the pipe 6, the clamping device can easily clamp the pipe 6, ensuring that the axis of the arc-shaped groove coincides with the axis of the positioning channel before bending.

[0060] The top surface of the fixed mold base 71 is also provided with an opening, and a movable roller 85 is provided in the opening. The wheel surface of the movable roller 85 is tangent to the curved surface of the inner wall of the lower positioning groove 711. A movable motor 84 is fixed on the support platform 81. The axial direction of the output end of the movable motor 84 is parallel to the first direction and is fixedly connected to the coaxial center line of the movable roller 85. A support roller 83 is provided at the end of the fixed mold base 71 opposite to the wheel mold base 21. The wheel surface of the support roller 83 is also tangent to the curved surface of the inner wall of the lower positioning groove 711. The support roller 83 and the movable roller 85 cooperate with each other to horizontally support the pipe 6. After the movable motor 84 drives the movable roller 85 to rotate, it can also drive the pipe 6 above it to move axially and adjust the axial position of the pipe 6.

[0061] With this structure, before mold closing, the moving motor 84 drives the moving roller 85 to rotate, which facilitates the adjustment of the axial position of the pipe 6. During mold closing, the fixed mold base 71 and the movable mold base 72 axially position the pipe 6 from both the top and bottom, while the clamping device clamps the pipe 6 in the horizontal direction, ensuring the positioning and clamping effect of the pipe 6. This prevents the part of the pipe 6 at the position of the positioning component 7 from axially shifting when the rotating component 1 is running, thereby ensuring the processing quality of the pipe 6.

[0062] Based on the above-mentioned pipe bending machine, the present invention provides a pipe bending method, comprising the following steps: S10. Preliminary preparation: Place the straight pipe 6 on the fixed mold base 71 (e.g., Figure 1 As shown), adjust the axial position of pipe 6 (e.g. Figure 2 Afterwards (as shown), the movable mold base 72 and the fixed mold base 71 are closed by the movable unit 73 to form a positioning channel that fits against the outer periphery of the pipe 6, so that the position of the pipe 6 to be bent is outside the positioning channel (as shown). Figure 3 ); S20, Clamping and Positioning: At the end of pipe 6 away from the positioning channel where it is to be bent, the pipe 6 is clamped and fixed by the interaction of the opposing clamping components (e.g., ...). Figure 4 (as shown) S30, Bending process: The clamping assembly is controlled to rotate to a preset angle by rotating assembly 1. The rotation axis of the clamping assembly extends in the vertical direction and is spaced from the axis of the pipe 6. S50, Remove the product: The clamping components separate from each other, and at the same time, the movable unit 73 controls the movable mold base 72 to separate from the fixed mold base 71 so as to remove the processed pipe 6; In step S20, the clamping assembly includes a translation unit 3 and a clamping unit 4. The translation unit 3 drives the clamping unit 4 to move along a first direction, which is parallel to the direction of the clamping assembly. When clamping, the axis of the pipe 6 is in a horizontal second direction. Translation unit 3 includes: A single-acting hydraulic cylinder 31 is distributed along the second direction and includes a cylinder barrel 32 and a piston assembly 33 that seals and penetrates one end of the cylinder barrel 32 near the pipe 6 and surrounds the cylinder barrel 32 to form a rod chamber and a rodless chamber. The cylinder barrel 32 has a built-in reset member that drives the piston assembly 33 toward the oil port 324 and has an air port 323 that communicates with the rod chamber. The switching valve 34 has an oil supply valve port 3411 for connecting to the output end of the hydraulic pump, an oil discharge valve port 3412 for connecting to the hydraulic tank, and a connecting valve port 3413 connected to each oil port 324. The working modes include oil supply mode, oil discharge mode, and oil isolation mode. In the oil supply mode, the oil supply valve port 3411 is connected to the connecting valve port 3413 and isolated from the oil discharge valve port 3412. In the oil discharge mode, the connecting valve port 3413 is connected to the oil discharge valve port 3412 and isolated from the oil supply valve port 3411. In the oil isolation mode, the oil supply valve port 3411, the oil discharge valve port 3412, and the connecting valve port 3413 are isolated from each other. The clamping unit 4 includes a clamping mechanism 41 corresponding to the single-acting hydraulic cylinder 31. The clamping mechanism 41 includes a clamping piece 411 and a pressing member. The clamping piece 411 is a deformable metal sheet connected to the piston assembly 33 through the pressing member. In its natural state, the clamping piece 411 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 6.

[0063] Using the above-mentioned pipe bending machine and method to bend pipe 6 has the following advantages compared with the prior art: First, after the movable mold base 72 and the fixed mold base 71 are separated, the straight pipe 6 can be placed horizontally through the lower positioning groove 711 on the fixed mold base 71 and the support roller 83 on the support platform 81. At the same time, it is also convenient to take out the pipe 6 after the bending process is completed. Second, the movable motor 84 drives the movable roller 85 to rotate, which facilitates the adjustment of the position of the pipe 6, so that the position of the pipe 6 to be bent protrudes from the lower positioning groove 711. Third, the movable unit 73 drives the movable mold base 72 to rotate downwards and close the mold base 71. The movable unit 73 and the gravity of the movable mold base 72 press down on the pipe 6, while the fixed mold base 71 is fixed in position, so as to achieve high-precision radial positioning of the pipe 6 and prevent the pipe 6 from shifting in the radial direction. Fourth, the positioning component 7 positions the pipe 6 in the vertical direction, while the clamping device clamps and fixes the pipe 6 in the horizontal direction. This facilitates the subsequent bending process and prevents the pipe 6 positioned by the positioning component 7 from radially shifting, thus improving the quality of the pipe bending process. Fifth, the clamping device makes surface contact with the outer surface of the pipe 6 through the clamping plate 411, which increases the pressure contact area and reduces the pressure on the pipe 6 while ensuring the same pressure, thus avoiding indentations on the outer surface of the pipe 6. Sixth, by moving multiple extrusion protrusions 413 radially and acting on the clamping plate 411, the force on the pipe 6 parts corresponding to the same clamping plate 411 tends to be uniform and consistent. Seventh, after the switching valve 34 is adjusted to the oil-separation mode, the rodless chambers of the single-acting hydraulic cylinder 31 cylinder 32 in the clamping unit 4 on the same side are interconnected. According to the pressure of the pipe 6 on the clamping plate 411, the hydraulic oil in the rodless chamber can automatically flow, thereby adjusting the pressure of each clamping plate 411. Specifically, when bending the pipe, the pressure of the pipe 6 on the clamping plate 411 is greater near the bending position and smaller away from the bending position. At this time, the hydraulic oil in the cylinder 32 near the bending position flows into the cylinder 32 away from the bending position, causing the piston assembly 33 near the bending position to retract while the piston assembly 33 away from the bending position extends outward, thereby reducing the pressure of the clamping plate 411 near the bending position on the pipe 6 and increasing the pressure of the clamping plate 411 away from the bending position on the pipe 6. While ensuring that the total pressure remains basically unchanged, the pressure distribution of each clamping plate 411 on the pipe 6 is kept uniform, which is conducive to improving the bending quality.

[0064] The above description is only a preferred embodiment of the present invention. It should be noted that for those skilled in the art, several improvements and modifications can be made without departing from the technical principles of the present invention, and these improvements and modifications should also be considered within the scope of protection of the present invention.

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 includes a body, which is fixed above the clamping table and axially parallel to the second direction. An oil port is provided at the bottom of the body for introducing hydraulic oil into the rodless chamber or for squeezing out hydraulic oil from the 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 clips are made of soft stainless steel sheets or nickel-plated brass sheets 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 pipe bending method, which employs the pipe bending machine as described in claim 8 or 9, 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 apart from the axis of the pipe. S40. Product Removal: 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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