Variable-a-value free bending forming device capable of processing pipe fittings of different outer diameters

Abstract

Disclosed is a variable-A-value free bending forming device capable of processing pipe fittings of different outer diameters. The device comprises a bending forming module, clamping and fixing modules, and a spherical bearing. The bending forming module is used for clamping a bent section of a pipe blank. Multiple clamping and fixing modules on a rear side of the bending forming module are evenly distributed along the circumference of the pipe blank, and are used for clamping and limiting an unbent section of the pipe blank during a bending forming process. Clamping mechanisms of the bending forming module and the clamping and fixing module have overall radial movement freedom and circumferential movement freedom for clamping jaws, and can meet the requirements for clamping pipe fittings of different outer diameters. Each clamping and fixing module adjusts the A-value during forming by adjusting the positions of an arc-shaped limiting block and a clamping support base. The present invention enables efficient single-die, multi-pipe processing in a free bending forming device for pipe fittings, reducing the time and cost required for die changes. The variable A value expands the application range of the device and further improves the forming quality of three-dimensional bent pipes.

Description

A free bending forming device with variable A value capable of processing pipes with different outer diameters Technical Field

[0001] The invention belongs to the field of free bending and forming of metal pipes, and particularly relates to a free bending and forming device with a variable A value which can process pipes with different outer diameters. Background Art

[0002] Metal pipe bends are among the most common fluid-handling components used in high-end manufacturing sectors such as aerospace, automotive, and medical. Compared to flat pipe bending methods like stretch bending, press bending, and push bending, free-bending pipe forming devices offer flexibility, customization, and efficiency. They can achieve three-dimensional bending and twisting of pipes, enabling the production of three-dimensional pipe bends that meet the diverse needs of various industries.

[0003] At present, the design and manufacture of free bending forming devices for pipe fittings have become relatively mature. The most common three-axis free bending forming devices have been widely used due to their simple operation. However, they can usually only be processed according to the "one mold and one tube" mode, that is, a set of devices can only process pipe fittings of fixed size specifications. If you want to process pipe fittings with different outer diameters, you need to replace the mold or equipment first, which leads to a decrease in processing efficiency and an increase in processing costs. In addition, the existing free bending forming devices cannot adjust the length of the bending deformation zone of the pipe fitting during the processing (hereinafter referred to as the A value). The A value determines the processing technology design of the free bending forming device for pipe fittings, and has an important influence on the forming quality of the bent pipe and the scope of application of the device. In order to realize the "one mold and multiple tubes" processing of the free bending forming device for pipe fittings and improve the forming performance of the spatial bent pipe to meet the relevant needs of industry and academia, there is now a need for a free bending forming device for pipe fittings that can clamp pipe fittings of different outer diameters and has an adjustable A value.

[0004] Summary of the Invention

[0005] In order to solve the problems in the background technology, the present invention provides a free bending and forming device with variable A value that can process pipes with different outer diameters. By changing the radial position and clamping state of the clamping mechanism in the bending and forming module and the clamping and fixing module, the clamping of pipes with different outer diameters can be achieved. The A value in the pipe bending and forming process is adjusted by adjusting the position of the arc limit block and the clamping support seat in the clamping and fixing module.

[0006] The technical solution adopted in the present invention is as follows:

[0007] 1. A free-bending device with variable A value capable of processing pipes with different outer diameters

[0008] It includes a spherical bearing, a bending forming module and multiple clamping and fixing modules; the bending forming module is used to clamp the bending section of the tube blank, and the bending forming module clamps tube blanks with different outer diameters by adjusting the radial position of the clamping mechanism I and the degree of opening of the clamping jaws; the bending forming module is fixed to the spherical bearing through spherical fit, and the external hydraulic cylinder indirectly controls the movement of the bending forming module by controlling the movement of the spherical bearing; multiple clamping and fixing modules are arranged behind the bending forming module, and the multiple clamping and fixing modules are circumferentially distributed on the circumference of the tube blank to clamp and limit the unbent section of the tube blank; the arc-shaped limit block of the clamping and fixing module has the freedom to move along the radial direction of the tube blank, and the clamping support seat of the clamping and fixing module has the freedom to move along the axial direction of the tube blank. By changing the position of the arc-shaped limit block in the radial direction and the position of the clamping support seat in the axial direction, the length of the bending deformation zone of the tube blank is adjusted, and then the bending forming quality of the tube blank is adjusted.

[0009] The bending forming module includes a bending die shell, a cross roller bearing, an outer gear ring, a driving gear, a support plate, a clamping claw support plate and two sets of clamping mechanisms I; a support plate is installed on the front side of the bending die shell, and an outer gear ring and a cross roller bearing are sequentially arranged between the support plate and the bending die shell, the support plate is fixedly connected to the inner ring of the cross roller bearing, and the outer ring of the outer gear ring and the outer ring of the cross roller bearing are jointly installed on the bending die shell; a gear motor is installed on the support plate through a motor fixing plate, and the output shaft of the gear motor is connected to a driving gear meshing with the outer gear ring; two ball screws are installed on both sides of the front of the support plate through a screw seat, and two clamping claw support plates respectively connected to the upper and lower parts are connected between the two ball screws, and the clamping claw support plates are perpendicular to the ball screws The lever is arranged and connected to the ball screw through a screw nut; two slide rails Ⅰ are installed on both sides of the two ball screws, and the two ends of each clamping jaw support plate are installed on the two slide rails Ⅰ through sliders Ⅰ, and the freedom of the clamping jaw support plate in other directions is limited by the cooperation of sliders Ⅰ and slide rails Ⅰ; the screw of each ball screw is connected to the output shaft of the pulley motor through a pulley and a synchronous belt; the ball screw is driven to rotate by the pulley motor, thereby driving the screw nut and the clamping jaw support plate fixed thereon to move in the radial direction; a group of clamping mechanisms Ⅰ is fixed in the middle of each clamping jaw support plate, and each group of clamping mechanisms Ⅰ includes a top block, a left clamping jaw and a right clamping jaw. By adjusting the radial position of the top block and the opening degree of the left clamping jaw and the right clamping jaw, the clamping of tube blanks with different outer diameters can be achieved.

[0010] The left and right clamping jaws of the clamping mechanism I are fixed in the middle of the clamping jaw support plate through a top block; the left and right clamping jaws together form a V-shaped structure with a variable angle, and the two are linked by a toothed structure with the same root module; a through hole is provided in the middle of the root of the left and right clamping jaws; the output shaft of the clamping jaw motor is sequentially extended into the through hole of the right clamping jaw through the clamping jaw support plate and the top block, and the through hole of the right clamping jaw and the output shaft of the clamping jaw motor are provided with upper and lower corresponding pin grooves, and the connection between the right clamping jaw and the output shaft of the clamping jaw motor is achieved by embedding pins in the upper and lower pin grooves; the pins are connected to the right The pin groove on the jaw through hole and the jaw motor output shaft is transitionally matched; the jaw shaft extends out of the left jaw through hole through the jaw support plate and the top block in sequence, and the front part of the left jaw is axially limited by a retaining spring installed on the jaw shaft; thrust bearings mounted on the jaw shaft and the jaw motor output shaft are respectively provided between the two jaws and the top block to eliminate the friction between the parts caused by the rotational motion; the right jaw is directly driven by the jaw motor, and the left jaw uses the toothed structure to realize the rotational motion in the opposite direction to the right jaw.

[0011] The inner and outer rings of the cross roller bearing can rotate relative to each other. Under the condition that the outer gear ring and the bending die shell are fixed, the driving gear is driven to rotate around the outer gear ring, and at the same time, the support plate and the clamping mechanism installed thereon are driven to produce circumferential movement relative to the bending die shell. During the processing, the driving gear is rotated to keep the center lines of the two sets of clamping mechanisms I always in the same straight line as the bending radius of the tube blank.

[0012] The inner surface of the spherical bearing and the outer surface of the bending mold shell are spherical surfaces that match each other; the outer surface of the bending mold shell is provided with upper and lower symmetrical circular limit columns, and the inner surface of the spherical bearing is provided with rectangular through grooves at positions corresponding to the upper and lower circular limit columns; the circumferential rotation of the bending mold shell relative to the spherical bearing is limited by the cooperation of the circular limit columns and the rectangular through grooves, so as to prevent the bending mold shell from rotating in the opposite direction while the active gear drives the support disk to rotate.

[0013] The clamping and fixing module includes a cylinder connecting rod, a clamping support seat, an arc-shaped limit block, a main transmission shaft, a push rod and a plurality of clamping mechanisms II similar to the bending forming module; a plurality of clamping mechanisms II are installed at equal intervals on the inner surface of the clamping support seat through the main transmission shaft along the axial direction of the tube blank; the clamping mechanism II is installed on the inner surface of the clamping support seat through the push block, and the structure of the clamping mechanism II is the same as that of the clamping mechanism I. The right clamping jaws of all clamping mechanisms II are uniformly driven by the main transmission shaft, and the main transmission shaft is driven by the transmission shaft motor and the coupling; the right clamping jaw is driven to rotate by the main transmission shaft, thereby driving the left clamping jaw engaged with the right clamping jaw to rotate in the opposite direction; the outer surface of the clamping support seat is installed with a plurality of clamping mechanisms II that are connected to the clamping support seat. The cylinder connecting rod moves relative to each other, and the two are connected by slide rail II and slider II. The cylinder connecting part and the clamping support seat have relative movement freedom along the axial direction of the tube blank; the end of the cylinder connecting rod is connected to the end of the clamping support seat through an electric push rod, and the front end of the electric push rod is installed on the mounting seat fixed at the end of the clamping support seat through the electric push rod shaft, and the clamping support seat is controlled to slide back and forth along the cylinder connecting rod by the electric push rod; the cylinder connecting rod is connected to multiple external cylinders evenly distributed along the axial direction of the tube blank, and the clamping and fixing module is driven to move along the radial direction of the tube blank as a whole through the extension and contraction of the cylinder, thereby changing the position of the clamping and fixing module in the radial direction, and realizing the clamping limit of tube blanks with different outer diameters.

[0014] The front end of the clamping support seat is equipped with an arc-shaped limit block through the push rod. The bottom of the arc limit block has an installation groove, and the top of the push rod is embedded in the installation groove. The bottom end of the push rod is connected to the clamping support seat by a threaded connection. The tail of the arc limit block is equipped with a slider III. Slider III cooperates with the slide rail III on the clamping support seat to achieve radial movement and limit the arc limit block's freedom in other directions. The radial position of the arc limit block is changed by adjusting the screwing depth of the push rod on the clamping support seat, so that the arc surface of the arc limit block contacts the inner conical surface of the bending die shell. The inner surface of the bending die shell extends backward to form an inner conical surface with an increasing inner diameter.

[0015] The length of the tube blank bending deformation zone is the A value, which is the length from the front end of the axially frontmost clamping jaw of the clamping and fixing module to the center of the top block of the bending forming module. The A value can be adjusted during the tube bending process by adjusting the radial position of the arc limit block and the axial position of the clamping support seat.

[0016] The clamping jaws of the two groups of clamping mechanisms I of the bending forming module are staggered along the axial direction of the tube blank to prevent mutual interference during clamping; the clamping jaws of the multiple clamping mechanisms II on the multiple clamping and fixing modules are staggered along the axial direction of the tube blank to avoid interference during clamping.

[0017] 2. Working method of the above-mentioned A-value variable free bending forming device capable of processing pipes with different outer diameters

[0018] The following steps are involved:

[0019] Step 1) The tube is placed in the position to be processed, and the top block of the clamping and fixing module is brought into contact with the outer surface of the tube by controlling the cylinder. The A value during the processing is determined, and the electric push rod and the top rod are adjusted to control the arc limit block to reach the position corresponding to the selected A value. The transmission shaft motor drives all the left and right clamping jaws of the clamping and fixing module to clamp the tube, thereby fixing the unbent section of the tube;

[0020] Step 2) The pulley motor drives the lead screw nut to move in the radial direction so that the top block of the bending forming module contacts the outer surface of the tube blank. The clamping motor then controls the left and right clamping jaws of the upper and lower clamping mechanisms to fully clamp the tube blank in preparation for bending.

[0021] Step 3) During the bending process, the external hydraulic cylinder indirectly controls the movement of the bending module to a specified position by controlling the translational motion of the spherical bearing, thereby meeting the bending radius conditions required for the tube blank bending. The contact between the bending die shell and the arc-shaped limit block ensures that the motion trajectory of the bending module is controllable. When the bending radius of the tube blank deviates from the original bending plane, the gear motor controls the rotation of the driving gear to achieve circumferential rotation of the clamping mechanism in the bending module, ensuring that the two sets of clamping mechanisms I are always located at the outermost convex side and the innermost concave side of the tube blank during the bending process.

[0022] Step 4) After processing is completed, loosen the clamping mechanisms of the bending and forming module and the clamping and fixing module in turn, and take out the formed pipe from the front of the bending and forming module. If the forming quality is not ideal, adjust the A value and return to step 1 to continue processing.

[0023] By separately adjusting the positions of the various clamping mechanisms on the bending and forming module and the clamping and fixing module, a set of bending devices can be used to process tube blanks with a variety of different outer diameters, which is convenient and efficient. By adjusting the radial position of the arc-shaped limit block and the axial position of the clamping support seat, the A value during the tube bending process is controlled, thereby improving the product forming quality while expanding the scope of application of the device.

[0024] Beneficial effects of the present invention:

[0025] (1) The present invention can realize the "one mold, multiple tubes" processing of the free bending forming device of the pipe fitting by adjusting the position and clamping state of the clamping mechanism in the bending forming module and the clamping and fixing module, thereby saving time and resources, reducing costs and improving production efficiency.

[0026] (2) The present invention can adjust the A value during the free bending forming process of the pipe fitting by adjusting the radial position of the arc limit block and the axial position of the clamping support seat. The A value directly affects the calculation of the motion trajectory of the entire device and the bending forming performance of the pipe fitting. The adjustment of the A value can expand the application range of the device while improving the forming quality of the spatial bend pipe.

[0027] (3) The circular limiting column of the bending mold shell of the present invention limits the freedom of movement of the bending forming module around the circumferential direction of the pipe, making the movement trajectory of the module more accurate and controllable during the processing and having higher processing stability. BRIEF DESCRIPTION OF THE DRAWINGS

[0028] FIG1 is an overall schematic diagram of the present invention.

[0029] FIG2 is a side sectional view of the present invention.

[0030] FIG3( a ), FIG3 ( b ) and FIG3 ( c ) are respectively a schematic diagram, a side view and a cross-sectional view of the bending forming module.

[0031] Figure 4(a) is an exploded view of the clamping mechanism in the bending module, and Figure 4(b) is a schematic diagram of the installation of the clamping support plate in the bending module.

[0032] FIG5 is a schematic diagram of a clamping and fixing module.

[0033] FIG6 is an exploded view of the clamping mechanism in the clamping and fixing module.

[0034] 7( a ) and 7 ( b ) are schematic diagrams and cross-sectional views of the arc-shaped limit block and the ejector rod, respectively, and FIG. 7 ( c ) is a rear view of the arc-shaped limit block.

[0035] FIG8( a ) and FIG8 ( b ) are schematic diagrams showing the state of the present invention when clamping pipes with different outer diameters.

[0036] FIG9(a) and FIG9(b) are schematic diagrams showing the state of adjusting the A value under the condition that the outer diameter of the pipe is the same according to the present invention.

[0037] In the figure: 1, spherical bearing, 2, tube blank, 3, bending forming module, 4, clamping and fixing module, 5, pulley, 6, screw seat, 7, synchronous belt, 8, pulley motor, 9, ball screw, 10, clamping jaw support plate, 11, slide rail I, 12, slider I, 13, left clamping jaw, 14, screw nut, 15, clamping jaw shaft, 16, retaining spring, 17, pin, 18, top block, 19, clamping jaw motor, 20, right clamping jaw, 21, driving gear, 22, gear motor, 23, Motor fixing plate, 24. Thrust bearing, 25. Support plate, 26. Bending mold housing, 27. Outer gear ring, 28. Cross roller bearing, 29. Push rod, 30. Arc limit block, 31. Slider III, 32. Slide rail III, 33. Clamping support seat, 34. Slide rail II, 35. Slider II, 36. Cylinder, 37. Cylinder connecting rod, 38. Electric push rod, 39. Mounting seat, 40. Electric push rod shaft, 41. Drive shaft motor, 42. Coupling, 43. Main drive shaft. DETAILED DESCRIPTION

[0038] The present invention will be further described in detail below with reference to the accompanying drawings and specific implementation examples.

[0039] As shown in Figures 1 and 2, a freely adjustable bending and forming device with a variable A value capable of processing pipes with different outer diameters comprises a spherical bearing 1, a bending and forming module 3, and three clamping and fixing modules 4 evenly distributed along the circumference of the pipe. The bending and forming module 3 and the spherical bearing 1 are fixed together by a spherical contact 1. An external hydraulic cylinder indirectly controls the movement of the bending and forming module 3 while controlling the translational movement of the spherical bearing 1. The rear end of the bending and forming module 3 contacts and is constrained by the clamping and fixing module 4, thereby ensuring that the motion trajectory of the bending and forming module 3 is controllable. By adjusting the position and state of the clamping mechanisms in the bending and forming module 3 and the clamping and fixing module 4, it is possible to clamp pipes 2 with different outer diameters.

[0040] As shown in Figures 3(a), 3(b) and 3(c), the bending forming module 3 includes a bending die shell 26, a cross roller bearing 28, an outer gear ring 27, a support plate 25, a driving gear 21, a clamping jaw support plate 10, a left clamping jaw 13, a right clamping jaw 20 and a top block 18, wherein the left clamping jaw 13, the right clamping jaw 20, the top block 18 and the clamping jaw support plate 10 constitute the clamping mechanism of the bending forming module 3. The bending forming module 3 has two sets of clamping mechanisms symmetrically arranged on the support plate 25. The two ends of the two sets of clamping mechanisms are installed on the slide rail Ⅰ 11 through the slider Ⅰ 12. The ball screw 9 and the screw nut 14 drive the entire clamping mechanism to move in the radial direction, and the pulley motor 8, the synchronous belt 7 and the pulley 5 drive the ball screw 9 to rotate. The support plate 25 is fixed to the inner ring of the cross roller bearing 28, while the outer ring gear 27 and the outer ring of the cross roller bearing 28 are mounted on the bending die housing 26. The inner and outer rings of the cross roller bearing 28 can rotate relative to each other. With the outer ring of the cross roller bearing 28 fixed, the gear motor 22 drives the driving gear 21, which is meshed with the outer ring gear 27, to rotate the support plate 25, thereby adjusting the circumferential position of the two clamping mechanisms. To ensure that the bending die housing 26 does not rotate in the opposite direction due to the reaction force when the driving gear 21 rotates, the spherical portion of the bending die housing 26 is symmetrically arranged with circular limit posts. The spherical bearing 1 that cooperates with them has corresponding rectangular slots. The combination of the circular limit posts and the rectangular slots restricts the circumferential freedom of movement of the bending die housing 26. During the machining process, the continuous rotation of the driving gear 21 ensures that the two sets of clamping mechanisms are always located on the outermost convex and innermost concave sides of the bend of the tube 2. In other words, the centerline of the two sets of clamping mechanisms is always aligned with the bend radius of the tube 2. To prevent interference between the jaws of the two sets of clamping mechanisms when clamping the tube 2, the jaws of the two sets of clamping mechanisms are staggered in the axial direction.

[0041] As shown in Figure 4, the jaw shaft 15 passes through the jaw support plate 10, the top block 18, the thrust bearing 35 and the left jaw 13 in sequence, and these parts are assembled together. The retaining spring 13 is used to limit the axial position of the left jaw 13, and the thrust bearing is used to eliminate the adverse effects of friction between the left jaw 13 and the top block 18. The right jaw 20 is directly installed on the jaw motor 19. The motor hole of the right jaw 20 is provided with a pin groove for transitional cooperation with the pin 17 and transmitting the rotational torque of the jaw motor 19. The roots of the left jaw 13 and the right jaw 20 are respectively provided with tooth structures of the same module, and the two realize the clamping movement of the tube blank 2 through the meshing transmission of the tooth structures.

[0042] As shown in Figures 5, 6 and 7, the clamping and fixing module 4 includes a cylinder connecting rod 37, a clamping support seat 33, an arc-shaped limit block 30, a main transmission shaft 43, a push rod 29 and multiple clamping mechanisms similar to the bending forming module 3. The multiple clamping mechanisms of the clamping and fixing module 4 are evenly distributed along the axial direction of the tube blank 2. The right clamping jaws 20 of all clamping mechanisms are uniformly driven by the main transmission shaft 43. The coupling 42 connects the main transmission shaft 43 and the transmission shaft motor 41 so that the transmission shaft motor 41 can provide power for the rotation of the main transmission shaft 43. The cylinder connecting rod 37 is connected to the external cylinder 36. The radial position of the entire clamping and fixing module 4 can be controlled by the contraction and extension of the cylinder 36. The cooperation of the slide rail Ⅱ 34 and the slider Ⅱ 35 enables the clamping support seat 33 and the cylinder connecting rod 37 to have axial relative movement freedom. The axial relative position of the two is controlled by the electric push rod 38. The tail of the electric push rod 38 is installed on the cylinder connecting rod 37, and the front end is fixed on the electric push rod shaft 40. The electric push rod shaft 40 is installed together with the mounting seat 39 fixed on the clamping support seat 33. The arc-shaped limit block 30 contacts the bending die housing 26 to limit the movement of the bending forming module 3. A mounting groove is provided at the bottom of the arc-shaped limit block 30 for mating with the top of the ejector pin 29. The ejector pin 29 is threadedly connected to the clamping support seat 33. Adjusting the depth of the ejector pin 29 screwed into the clamping support seat 33 adjusts the radial position of the arc-shaped limit block 30. The tail of the arc-shaped limit block 30, through the cooperation of slider III 31 and rail III 32, limits the degrees of freedom in all directions except the radial direction to ensure the stability of the movement. By comprehensively considering the radial position of the arc-shaped limit block 30 and the axial position of the clamping support seat 33, the A value can be adjusted during the processing process.

[0043] As shown in FIG8 , when processing tube blanks 2 with different outer diameters, the tube blank 2 is first placed in the position to be processed, and then the clamping mechanisms of the clamping and fixing module 4 and the bending and forming module 3 are controlled in sequence to approach and clamp the tube blank 2. Because the outer diameters of the tube blanks 2 are different, the extension amount of the cylinder 36, the radial position of the screw nut 14, and the angle between the left clamping jaw 13 and the right clamping jaw 20 in the clamping mechanism will all be different.

[0044] As shown in Figure 9, under the condition that the outer diameter of the processed tube blank 2 remains unchanged, the A value during the processing process can be changed by adjusting the radial position of the arc limit block 30 and the axial position of the clamping support seat 33. Taking the reduction of the A value as an example, if the A value at this time is L1 in Figure 9 (a), if you want to reduce the A value, you need to adjust the arc limit block 30 in the radial inward direction while adjusting the clamping support seat 33 toward the bending mold shell 26, so that the A value can be changed to L2 in Figure 9 (b).

[0045] Specific implementation method:

[0046] (1) First, place the tube blank 2 at the position to be processed, control the cylinder 36 to extend the cylinder rod so that the top block 18 of each clamping mechanism in the clamping and fixing module 4 contacts the outer surface of the tube blank 2, select the A value in this processing process, control the arc limit block 30 to reach the position corresponding to the selected A value through the electric push rod 38 and the top rod 29, and drive the transmission shaft motor 41 to drive all the left clamping jaws 13 and the right clamping jaws 20 of the clamping and fixing module 4 to clamp the tube blank 2 at the same time, thereby fixing the unbent section of the tube blank 2.

[0047] (2) The pulley motor 8 drives the lead screw nut 14 to move in the radial direction, controlling the top block 18 of the bending forming module 3 to contact the outer surface of the tube blank 2. Then, the two clamping motors 19 drive the left clamping jaw 13 and the right clamping jaw 20 of the two symmetrically arranged clamping mechanisms to completely clamp the tube blank 2 in preparation for bending.

[0048] (3) During the bending process, the external hydraulic cylinder indirectly controls the movement of the bending module 3 to the specified position by controlling the translational movement of the spherical bearing 1, thereby meeting the bending radius conditions required for the bending of the tube blank 2. The contact between the tail of the bending die shell 26 and the arc-shaped limit block 30 ensures that the movement trajectory of the bending module 3 is controllable. When the bending radius of the tube blank 2 deviates from the original bending plane, the gear motor 22 controls the driving gear 21 to rotate to realize the circumferential rotation of the clamping mechanism in the bending module 3, ensuring that the two sets of clamping mechanisms are always located at the outermost convex side and the innermost concave side during the bending process of the tube blank 2.

[0049] (4) After the processing is completed, the clamping mechanisms of the bending forming module 3 and the clamping and fixing module 4 are released in turn, and the formed pipe is taken out from the front of the bending forming module 3. If the processing technology needs to be adjusted to improve the quality of the bending pipe, the A value can be adjusted and steps (1) to (3) can be repeated to continue the processing.

Claims

1. A free bending forming device with variable A value capable of processing pipes with different outer diameters, characterized in that: It comprises a spherical bearing (1), a bending and forming module (3), and a plurality of clamping and fixing modules (4); The bending forming module (3) is used to clamp the bending section of the tube blank (8). The bending forming module (3) clamps tube blanks (2) of different outer diameters by adjusting the radial position of the clamping mechanism I and the degree of opening of the clamping jaws. The bending forming module (3) is fixed to the spherical bearing (1) through spherical fit, and the external hydraulic cylinder indirectly controls the movement of the bending forming module (3) by controlling the movement of the spherical bearing (1). A plurality of clamping and fixing modules (4) are arranged behind the bending and forming module (3). The plurality of clamping and fixing modules (4) are evenly distributed on the circumference of the tube blank (8) in the circumferential direction to clamp and limit the unbent section of the tube blank (2); the arc-shaped limiting block (30) of the clamping and fixing module (4) has the freedom to move along the radial direction of the tube blank (2), and the clamping support seat (33) of the clamping and fixing module (4) has the freedom to move along the axial direction of the tube blank (2). By changing the position of the arc-shaped limiting block (30) in the radial direction and the position of the clamping support seat (33) in the axial direction, the length of the bending deformation zone of the tube blank (2) is adjusted, thereby adjusting the bending and forming quality of the tube blank (2).

2. The device for freely bending and forming pipes with variable A values capable of processing pipes with different outer diameters according to claim 1, characterized in that: The bending forming module (3) comprises a bending die shell (26), a cross roller bearing (28), an outer gear ring (27), a driving gear (21), a support plate (25), a clamping claw support plate (10) and two sets of clamping mechanisms I; A support plate (25) is installed on the front side of the bending die shell (26), and an outer gear ring (27) and a cross roller bearing (28) are sequentially arranged between the support plate (25) and the bending die shell (26). The support plate (25) is fixedly connected to the inner ring of the cross roller bearing (28), and the outer ring of the outer gear ring (27) and the outer ring of the cross roller bearing (28) are jointly installed on the bending die shell (26); a gear motor (22) is installed on the support plate (25) through a motor fixing plate (23), and the output shaft of the gear motor (22) is connected to a driving gear (21) meshing with the outer gear ring (27); Two ball screws (9) are installed on both sides of the front of the support plate (25) through the screw seat (6), and two clamping claw support plates (10) are connected to the upper and lower parts respectively between the two ball screws (9). The clamping claw support plates (10) are arranged perpendicular to the ball screws and are connected to the ball screws (9) through the screw nuts (14); two slide rails I (11) are installed on both sides of the two ball screws (9), and the two ends of each clamping claw support plate (10) are installed on the two slide rails I (11) through the slider I (12); The screw of each ball screw (9) is connected to the output shaft of the pulley motor (8) through the pulley (5) and the synchronous belt (7); the pulley motor (8) drives the ball screw (9) to rotate and then drives the screw nut (14) and the clamping claw support plate (10) fixed thereon to move in the radial direction; A group of clamping mechanisms I is fixed in the middle of each clamping jaw support plate (10). Each group of clamping mechanisms I includes a top block (18), a left clamping jaw (13) and a right clamping jaw (20). By adjusting the radial position of the top block (18) and the opening degree of the left clamping jaw (13) and the right clamping jaw (20), the clamping of tube blanks (8) with different outer diameters can be achieved.

3. The device for freely bending and forming pipes with variable A values capable of processing pipes with different outer diameters according to claim 2, characterized in that: The left clamping jaw (13) and the right clamping jaw (20) of the clamping mechanism I are fixed in the middle of the clamping jaw support plate (10) through a top block (18); the left clamping jaw (13) and the right clamping jaw (20) together form a V-shaped structure with a variable angle, and the two are linked by tooth-shaped structures with the same root module; a through hole is opened in the middle of the root of the left clamping jaw (13) and the right clamping jaw (20); The output shaft of the clamping jaw motor (19) sequentially passes through the clamping jaw support plate (10) and the top block (18) and extends into the through hole of the right clamping jaw (20). The through hole of the right clamping jaw (20) and the output shaft of the clamping jaw motor (19) are provided with upper and lower corresponding pin grooves. The connection between the right clamping jaw (20) and the output shaft of the clamping jaw motor (19) is achieved by embedding pins (17) in the upper and lower pin grooves. The clamping jaw shaft (15) sequentially passes through the clamping jaw support plate (10) and the top block (18) and extends out of the through hole of the left clamping jaw (13). The front part of the left clamping jaw (13) is axially limited by a retaining spring (16) installed on the clamping jaw shaft (15). Thrust bearings (24) are respectively provided between the two clamping jaws and the top block (18) and are sleeved on the clamping jaw shaft (15) and the output shaft of the clamping jaw motor (19). The right clamping jaw (20) is directly driven by the clamping jaw motor (19), and the left clamping jaw (13) is rotated in the opposite direction to the right clamping jaw (20) by means of a tooth structure.

4. The device for freely bending and forming pipes with variable A values capable of processing pipes with different outer diameters according to claim 2, characterized in that: The inner ring and outer ring of the cross roller bearing (28) can rotate relative to each other, and under the condition that the outer ring gear (27) and the bending die shell (26) are fixed, the driving gear (21) is driven to rotate around the outer ring gear (27), while driving the support plate (25) and the clamping mechanism installed thereon to generate circumferential movement relative to the bending die shell (26); During the processing, the driving gear (21) is rotated to keep the center line of the two groups of clamping mechanisms I always in the same straight line with the bending radius of the tube blank (2).

5. The device for freely bending and forming pipes with variable A values capable of processing pipes with different outer diameters according to claim 2, characterized in that: The inner surface of the spherical bearing (1) and the outer surface of the bending die housing (26) are spherical surfaces that fit together; the outer surface of the bending die housing (26) is provided with upper and lower symmetrical circular limiting columns, and the inner surface of the spherical bearing (1) is provided with rectangular through-slots at positions corresponding to the upper and lower circular limiting columns; the circumferential rotation of the bending die housing (26) relative to the spherical bearing (1) is limited by the cooperation of the circular limiting columns and the rectangular through-slots, so as to prevent the bending die housing (26) from rotating in the opposite direction while the driving gear (21) drives the support plate (25) to rotate.

6. The device for freely bending and forming pipes with variable A values capable of processing pipes with different outer diameters according to claim 1, characterized in that: The clamping and fixing module (4) comprises a cylinder connecting rod (37), a clamping support seat (33), an arc-shaped limit block (30), a main transmission shaft (43), a push rod (29), and a plurality of clamping mechanisms II similar to the bending and forming module (3); A plurality of clamping mechanisms II are installed at equal intervals on the inner surface of the clamping support seat (33) along the axial direction of the tube blank (8) via a main transmission shaft (43); the clamping mechanism II is installed on the inner surface of the clamping support seat (33) via a top block (18); the clamping mechanism II has the same structure as the clamping mechanism I; the right clamping jaws (20) of all the clamping mechanisms II are uniformly driven by the main transmission shaft (43), and the main transmission shaft (43) is driven by a transmission shaft motor (41) and a coupling (42); the right clamping jaw (20) is driven to rotate by the main transmission shaft (43), thereby driving the left clamping jaw (13) engaged with the right clamping jaw (20) to rotate in the opposite direction; The outer surface of the clamping support seat (33) is provided with a cylinder connecting rod (37) which moves relative to the clamping support seat (33), and the two are connected to the slider II (35) through the slide rail II (34); the end of the cylinder connecting rod (37) is connected to the end of the clamping support seat (33) through the electric push rod (38), and the front end of the electric push rod (38) is installed on the mounting seat (39) fixed at the end of the clamping support seat (33) through the electric push rod shaft (40), and the clamping support seat (33) is controlled by the electric push rod (38) to slide forward and backward along the cylinder connecting rod (37); The cylinder connecting rod (37) is connected to a plurality of external cylinders (36) uniformly distributed along the axial direction of the tube blank (8). The cylinders (36) are extended and retracted to drive the clamping and fixing module (4) to move along the radial direction of the tube blank (8) as a whole, thereby changing the position of the clamping and fixing module (4) in the radial direction, thereby achieving clamping and limiting of tube blanks (8) with different outer diameters. The front end of the clamping support seat (33) is provided with an arc-shaped limit block (30) through the push rod (29); a mounting groove is provided at the bottom of the arc-shaped limit block (30), the top end of the push rod (29) is embedded in the mounting groove, and the bottom end of the push rod (29) is connected to the clamping support seat (33) through a threaded connection; a slider III (31) is provided at the tail end of the arc-shaped limit block (30), and the slider III (31) realizes radial movement by cooperating with the slide rail III (32) on the clamping support seat (33) and limits the freedom of the arc-shaped limit block (30) in other directions; the position of the arc-shaped limit block (30) in the radial direction is changed by adjusting the screwing depth of the push rod (29) on the clamping support seat (33), so that the arc surface of the arc-shaped limit block (30) is against the inner conical surface of the bending mold shell (26).

7. The device for freely bending and forming pipes with variable A values capable of processing pipes with different outer diameters according to claim 6, characterized in that: The length of the bending deformation zone of the tube blank (2) is A value, which is the length from the front end of the axially frontmost clamping jaw of the clamping and fixing module to the center of the top block of the bending and forming module. The A value is adjusted during the tube bending process by adjusting the radial position of the arc-shaped limit block (30) and the axial position of the clamping support seat (33).

8. A free bending forming device with variable A value capable of processing pipes with different outer diameters according to claim 3 or 6, characterized in that: The clamping claws of the two groups of clamping mechanisms I of the bending and forming module (3) are staggered along the axial direction of the tube blank (8) to prevent mutual interference during clamping; The clamping claws of the multiple clamping mechanisms II on the multiple clamping and fixing modules (4) are staggered along the axial direction of the tube blank (8) to avoid interference during clamping.

9. A method for using the A-value variable free bending forming device capable of processing pipes with different outer diameters according to any one of claims 1 to 8, characterized in that: The following steps are involved: Step 1) placing the tube blank (2) at a position to be processed, controlling the cylinder (36) so that the top block (18) of the clamping and fixing module (4) contacts the outer surface of the tube blank (2), determining the A value during the processing, adjusting the electric push rod (38) and the top rod (29) to control the arc-shaped limit block (30) to reach a position corresponding to the selected A value, and driving all the left clamping jaws (13) and the right clamping jaws (20) of the clamping and fixing module (4) by the transmission shaft motor (41) to clamp the tube blank (2), thereby achieving fixation of the unbent section of the tube blank (2); Step 2) The lead screw nut (14) is driven by the pulley motor (8) to move in the radial direction so that the top block (18) of the bending forming module (3) contacts the outer surface of the tube blank (2). Then, the clamping motor (19) controls the left clamping jaw (13) and the right clamping jaw (20) of the upper and lower clamping mechanisms respectively to completely clamp the tube blank (2) and prepare for bending. Step 3) During the bending process, the external hydraulic cylinder indirectly controls the bending module (3) to move to a specified position by controlling the translational movement of the spherical bearing (1), thereby satisfying the bending radius condition required for bending the tube blank (2); The contact between the bending die shell (26) and the arc-shaped limit block (30) ensures that the motion trajectory of the bending forming module (3) is controllable. When the bending radius of the tube blank (2) deviates from the original bending plane, the gear motor (22) controls the driving gear (21) to rotate to realize the circumferential rotation of the clamping mechanism in the bending forming module (3), ensuring that the two sets of clamping mechanisms I are always located at the outermost convex side and the innermost concave side during the bending process of the tube blank (2); After step 4) the processing is completed, the clamping mechanisms of the bending and forming module (3) and the clamping and fixing module (4) are released in sequence, and the formed pipe is taken out from the front of the bending and forming module (3). If the forming quality is not ideal, the A value is adjusted and the process is returned to step 1 to continue.

10. The working method according to claim 9, characterized in that: By respectively adjusting the positions of the various clamping mechanisms on the bending and forming module (3) and the clamping and fixing module (4), a set of bending devices can be used to process tube blanks (2) with various outer diameters; and by adjusting the radial position of the arc-shaped limit block (30) and the axial position of the clamping support seat (33), the A value during the bending and forming process of the tube blank (2) is controlled.

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