Equipment for Axial Upsetting Forming of Large-Diameter Metal Bellows and Its Processing Method

Abstract

The present invention relates to an equipment and a processing method for axial upsetting forming of large-diameter metal bellows, belonging to the technical field of metal processing. An equipment for axial upsetting forming of large-diameter metal bellows includes a base. The special feature is that a fixed plate A and a fixed plate B are installed on the base. A fixed die base plate and a movable die base plate are installed between the fixed plate A and the fixed plate B. The fixed plate A, the fixed plate B, the fixed die base plate and the movable die base plate all have central holes. The fixed plate B, the fixed die base plate and the movable die base plate are connected in series as a whole through connecting beam columns, and the movable die base plate is slidably installed on the connecting beam columns. The piston rod end of a hydraulic cylinder fixedly installed on the fixed plate A is connected to the movable die base plate; a follower frame is fixed on the movable die base plate, the connecting end of a follower sealing assembly is fixed on the follower frame, and the sealing end of the follower sealing assembly is located in the central hole of the movable die base plate; a forming die A is installed around the central hole on the fixed die base plate, and a forming die B is installed around the central hole on the movable die base plate.

Description

Technical Field

[0001] The present invention relates to an equipment and a processing method for axial upsetting forming of large-diameter metal bellows, belonging to the technical field of metal processing. Background Art

[0002] Metal bellows are widely used as flexible connectors in industrial production. However, different application fields have different performance requirements for metal bellows. At present, due to deficiencies in the structural design and manufacturing technology of metal bellows themselves, various failure problems such as stress concentration fracture, brittle fracture, corrosion fracture, low fatigue life, and deformation extrusion failure occur in bellows under different working conditions.

[0003] The above problems mainly occur when forming metal bellows, especially in traditional hydroforming. Since there is no axial feed during the bulging stage, the deformation amount in the center area of the wave crest is large and the wall thickness reduction is serious. After forming, the wall thickness distribution from the wave trough to the wave crest is seriously uneven, resulting in a large difference in residual stress between the wave crest and wave trough positions of the metal bellows. As a result, in engineering applications, corrosion cracking is likely to occur earlier in the stress concentration area, seriously affecting the service performance and service life of the metal bellows. In addition, when the expansion amount of hydroforming is large, cracking is likely to occur at the weld of the pipe. Therefore, reducing the strain and wall thickness reduction rate during forming is of great significance for improving the manufacturing and service performance of bellows.

[0004] At the same time, existing processing equipment and processing methods also have deficiencies in the continuous forming of bellows. One is that it is not convenient for the continuous forming of large pipes. The other is that when forming waves, the problem of uneven wall thickness of the pipe wall will occur. Summary of the Invention

[0005] In order to achieve the single-wave continuous forming of bellows, the present application provides an equipment for axial upsetting forming of large-diameter metal bellows, and a method for processing bellows using this equipment.

[0006] The present invention solves the above technical problems through the following technical solutions:

[0007] An equipment for axial upsetting forming of large-diameter metal bellows, including a base. The special feature is that a fixed plate A and a fixed plate B are installed on the base. A fixed die seat plate and a moving die seat plate are installed between the fixed plate A and the fixed plate B. The fixed plate A, the fixed plate B, the fixed die seat plate and the moving die seat plate all have central holes. The fixed plate B, the fixed plate A, the fixed die seat plate and the moving die seat plate are connected in series as a whole by connecting beam columns. And the moving die seat plate is slidably installed on the connecting beam columns. The end of the piston rod of the hydraulic cylinder fixed on the fixed plate B is connected to the moving die seat plate; The follower frame is fixed on the moving die seat plate. The connecting end of the follower seal assembly is fixed on the follower frame. The sealing end of the follower seal assembly is located in the central hole of the moving die seat plate; The moving seal assembly is installed on the base through a slider and a slide rail; A forming die A is installed around the central hole on the fixed die seat plate, and a forming die B is installed around the central hole on the moving die seat plate. Among them, the fixed die seat plate can also be installed on the fixed plate B through a hydraulic cylinder in the same way as the moving die seat plate.

[0008] The advantages of the above technical solution are as follows: In the above equipment, the fixed plate A, the fixed plate B, the fixed die seat plate and the moving die seat plate are connected in series by connecting beam columns to ensure that their central holes are on the same axis. The advantage of this design is that both the moving seal assembly and the follower seal assembly can well control the installation position; The moving seal assembly is installed on the frame through the slider and the track, which can ensure the smoothness of movement. The moving seal assembly can be driven by a motor or a hydraulic cylinder; The follower seal assembly is connected to the moving die seat plate as a whole through the follower frame. In this way, the sealing position is fixed. Only by adjusting the position of the pipe, the sealing can be carried out at any time, and then the pressure is applied for processing.

[0009] On the basis of the above technical solution, the present application makes the following improvements and enhancements to the above technical solution:

[0010] Further, the forming die A is composed of at least two splicing components A; The splicing component A includes a splicing sliding plate A and a forming part A thereon. The forming part A is a partial ring. The splicing sliding plate A includes a sliding tail plate for guiding and a crescent plate at the front end. The sliding tail plate is inserted into the chute of the fixed seat block. The splicing cylinder is fixed on the fixed seat block. The piston rod of the splicing cylinder A is connected to the ear plate on the splicing seat block; A necking slope is arranged on the joint side of the inner wall of the forming part A and the splicing sliding plate A. A forming half-cavity A is arranged on the forming end face of the forming part A. A transition surface is arranged from the necking slope to the forming half-cavity A.

[0011] Further, the splicing components A are spliced into a complete ring cavity. When the die is closed, the sealing forming can be completed. When the die is opened, it can ensure the wave inlet and outlet during the continuous production of subsequent waves.

[0012] Further, the cross-section of the forming half-cavity A includes a transition arc, a side wall arc, a shoulder arc and a top arc.

[0013] Further, the forming die B includes at least two assembled components B. The assembled component B includes a crescent ring B. A guiding slide plate B is arranged on the outer ring wall of the crescent ring B. The guiding ring plate B is inserted into the slot of the fixed seat B. The assembling cylinder B is fixed on the fixed seat B. The end of the piston rod of the assembling cylinder B is connected to the ear plate B on the crescent ring B. A forming part B is installed on the inner ring of the crescent ring B. The end face of the forming part B that is joined with the forming part A is provided with a forming half-cavity that is mirror-image to the forming half-cavity A.

[0014] The beneficial effects of the above technical features in this application are as follows: Both the forming die A and the forming die B adopt a combined structure. The advantage of such a structure is to realize the positioning and opening / closing of the die. By using a cylinder to open and close the die, the clamping position on the pipe can be determined. The forming die A and the forming die B each have half of a forming cavity. In this way, during processing, the length of the pipe required for forming can be controlled, that is, the requirements for pipe forming can be ensured. At the same time, as the moving die base plate moves towards the fixed die base plate, the forming die B supplies axial material to the pipe, which can effectively compensate for the formed waveform and ensure the thickness of the formed wave.

[0015] Further, the moving seal assembly includes a counterweight seat. A slider is installed at the bottom of the counterweight seat. A connecting rod A is installed at the top of the counterweight seat. A sealing head A is installed at the end of the connecting rod A. The sealing head A is in a barrel shape. A raised sealing ring seat A is arranged on the outer side of the barrel edge of the sealing head A. A sealing groove is arranged on the sealing ring seat A. An annular expansion airbag is installed at the bottom of the sealing groove. A sealing ring A is sleeved outside the expansion airbag. Among them, the long rod at the end of the connecting rod A is replaceable to adapt to initial blanks of different lengths.

[0016] The beneficial effects of the above technical features in this application are as follows: The expansion airbag is an annular airbag. By charging and discharging high-pressure air into the expansion airbag, the sealing ring A outside it is controlled to expand and seal or contract to release the seal. In this way, the internal seal of the pipe can be ensured during the processing of a single wave. After the single wave processing is completed, enough space is left for the pipe to move forward. At the same time, the friction between the inner wall of the pipe and the sealing ring A is reduced, the service life of the sealing ring A is increased, and the cost is reduced. At the same time, when low-pressure air is filled into the expansion airbag, the formed pipe can still be fixed, which is beneficial to the automatic movement of the formed pipe and beneficial to the automatic loading and unloading of the formed pipe.

[0017] Further, the follow-up seal assembly includes a barrel-shaped sealing head B. The sealing head B is fixedly installed on the follow-up fixing plate through a fixed connecting rod. The follow-up fixing plate is fixed on the follow-up frame. Among them, the fixed connecting rod can be replaced to adapt to formed parts of different lengths. An internal pressure charging pipe is installed inside the connecting rod, and an internal pressure charging joint passing through the sealing head B.

[0018] The beneficial effects of the above technical features in this application are as follows: The sealing structure of the follower seal head is also designed to be the same as that of seal head A, and the expansion and contraction of the outer sealing ring are controlled by the expansion airbag.

[0019] With the use of follow-up sealing, the sealing structure can float synchronously with the pressure head. There is no relative displacement and sliding between the sealing ring and the wall of the formed workpiece, ensuring reliable sealing and a long service life of the sealing ring. The floating seal ensures the feeding amount during the forming process, thereby guaranteeing the shape accuracy and avoiding the problem that traditional fixed internal seals cannot accurately control the feeding amount, and solving the thinning problem of large-deformation parts such as compensators.

[0020] Furthermore, the device further includes a pressure system and an electrical control system.

[0021] The pressure system provides hydraulic pressure and air pressure for the system, and the electrical control system controls the operation of the device.

[0022] A processing method for a metal bellows, characterized by comprising the following steps:

[0023] Step 1, loading: Place the pipe on the arc-shaped material supporting part of the support frame on the rack. There are rollers on the arc-shaped material supporting part of the support frame, and push the pipe through the middle holes of the fixed plate A and the fixed die seat plate; the moving seal assembly acts, moves on the slide rail through the counterweight seat, drives the seal head A at the end of the connecting rod A to move and be inserted into the center of the pipe, and extends to the forming die A; the forming die A on the fixed die seat plate acts, and the forming part A of the forming die A closes the mold under the drive of the splicing cylinder, and is spliced into a complete forming die A; the complete forming die A and the seal head A clamp and seal one end of the pipe.

[0024] Step 2, pre-closing the mold: The hydraulic cylinder pushes the moving die seat plate to move, and the follower seal assembly moves together with the moving die seat plate. When the distance between the moving die seat plate and the fixed die seat plate reaches the set distance, stop moving. The forming die B on the moving die seat plate acts, and the splicing assembly B of the forming die is spliced into a complete forming die B under the drive of the splicing cylinder B; the complete forming die B and the seal head B of the follower seal assembly clamp and seal the other end of the pipe.

[0025] Step 3, adopt the axial upsetting forming technology to form under the combined action of die axial feeding and internal pressure:

[0026] After the mold A, mold B, and the corresponding moving seal assembly and follower seal assembly move to the set positions, a sealed cavity is formed between the tube blank and the seal assembly. An inert gas slightly greater than the yield pressure of the tube blank is filled into the interior of the tube blank, causing the material in the deformation zone of the tube blank to yield and undergo a certain amount of deformation. Under the support of the forming internal pressure, the hydraulic cylinder pushes the moving die base plate, the forming die B on the moving die base plate, and the follower seal assembly 13 together to move, providing axial feed to cause the sealed part of the tube blank to bend and gradually fit into the cavity formed by mold A and mold B until the molds are fully closed. The sealed part of the tube blank completes the final mold fitting under the action of the bending force provided by the moving mold and the forming internal pressure. By using the axial upsetting forming process, the wall thickness reduction rate of the corrugated pipe is reduced, thereby reducing the large residual stress at the wave crest and wave trough positions caused by severe wall thickness reduction, and improving the service performance and fatigue life of the metal corrugated pipe.

[0027] Forming is carried out by the method of applying pressure while axially supplying until the molds are closed. According to the material and wall thickness of the pipe material, the pressure inside the sealed section and the axial supply length are controlled. Specifically, it is internal pressure application and axial supply forming: by filling high-pressure gas into the sealed space, under the support of the pressure, the hydraulic right cylinder on the fixed plate A simultaneously pushes the fixed die base plate) to move towards the moving die base plate until mold A and mold B are closed. The pipe material forms the waveform of the closed molds A and B under the action of the internal pressure support and axial supply. By using the axial upsetting forming process, the wall thickness reduction rate of the corrugated pipe can be reduced, thereby reducing the large residual stress at the wave crest and wave trough positions caused by severe wall thickness reduction, and improving the service performance and fatigue life of the metal corrugated pipe. Brief Description of the Drawings

[0028] Figure 1 It is a three-dimensional structural schematic diagram of a device for axial upsetting forming of large-diameter metal corrugated pipes according to the present application;

[0029] Figure 2 is Figure 1 front view;

[0030] Figure 3 is a structural schematic diagram of the pipe material installed on the equipment;

[0031] Figure 4 is a schematic diagram of the installation relationship among the fixed plate A, fixed plate B, fixed die base plate, and moving die base plate;

[0032] Figure 5 is a three-dimensional structural schematic diagram of the forming die A;

[0033] Figure 6 is a structural schematic diagram of the splicing component A;

[0034] Figure 7 is Figure 6 enlarged view at A in

[0035] Figure 8 Schematic three-dimensional structure diagram of the forming die B;

[0036] Figure 9 Schematic three-dimensional structure diagram of the splicing component B;

[0037] Figure 10 It is Figure 9 The enlarged view at position B in

[0038] Figure 11 Schematic three-dimensional structure diagram of the movable sealing component;

[0039] Figure 12 Cross-sectional view of the sealing head A connecting rod and the sealing head;

[0040] Figure 13 Cross-sectional installation structure diagram of the expansion airbag and the sealing ring A of the sealing head A;

[0041] Figure 14 Schematic three-dimensional structure diagram of the follow-up sealing component;

[0042] Figure 15 Schematic installation structure diagram of the pressure system and the electrical control system with the equipment of the present application.

[0043] Explanation of reference numerals: Base - 1, fixed support frame - 2, follow-up frame - 3, movable sealing component - 4, fixed plate A - 5, fixed die base plate - 6, splicing component A - 7, fixed plate B - 8, movable die base plate - 9, splicing component B - 10, connecting beam column - 11, support frame - 12, follow-up sealing component - 13, support cylinder - 14, hydraulic cylinder - 15, pipe - 100, pressure system - 101, electrical control system - 102,

[0044] Counterweight seat - 4.1, connecting rod A - 4.2, sealing head A connecting rod - 4.21, sealing head A - 4.3, sealing ring seat A - 4.31, expansion airbag - 4.32, sealing ring A - 4.33, sealing ring - 4.34,

[0045] Splicing sliding plate A - 7.1, fixed seat block - 7.2, splicing cylinder A - 7.3, ear plate - 7.4, forming part A - 7.5, forming half cavity A - 7.51, transition arc - 7.511, side wall arc - 7.512, shoulder arc - 7.513, top arc - 7.514, necking inclined plane - 7.53, crescent plate - 7.11, sliding tail plate - 7.12,

[0046] Crescent ring B - 10.1, fixed seat B - 10.2, splicing cylinder B - 10.3, ear plate B - 10.4, forming part B - 10.5,

[0047] Sealing head B-15.1, fixed connecting rod-15.2, follower fixing plate-15.3. Detailed implementation mode

[0048] The following embodiments are combined with the accompanying drawings only to illustrate the technical solutions recorded in the claims, and are not intended to limit the scope of protection of the claims.

[0049] Combined with the attached Figures 1-4 A device for axial upsetting forming of large-diameter metal bellows includes a base 1. A fixing plate A5 and a fixing plate B8 are installed on the base 1. A fixed die base plate 6 and a moving die base plate 9 are installed between the fixing plate A5 and the fixing plate B8. The fixing plate A5, the fixing plate B8, the fixed die base plate 6 and the moving die base plate 9 all have a middle hole. The fixing plate B8, the fixing plate A5, the fixed die base plate 6 and the moving die base plate 9 are connected in series as a whole through connecting beam columns 11, and the moving die base plate 9 is slidably installed on the connecting beam columns 11. The end of the piston rod of the hydraulic cylinder 15 fixedly installed on the fixing plate B8 is connected to the moving die base plate 9. The follower frame 3 is fixed on the moving die base plate 9. The connecting end of the follower sealing assembly 13 is fixed on the follower frame 3, and the sealing end of the follower sealing assembly 13 is located in the middle hole of the moving die base plate 9. The moving sealing assembly 4 is installed on the base 1 through a slider and a slide rail. A forming die A is installed around the middle hole on the fixed die base plate 6, and a forming die B is installed around the middle hole on the moving die base plate 9. Among them, the follower frame 3 is replaceable to adapt to forming parts of different lengths; the fixed support frame 2 for supporting the fixing plate A5 and the fixed die base plate 6 is also replaceable to adapt to initial blanks of different lengths.

[0050] On the basis of the above technical solutions, the present application makes the following improvements and enhancements to the above technical solutions:

[0051] Combined with the attached Figures 5-7 Among them, the forming die A is composed of at least two splicing components A7; the splicing component A7 includes a splicing sliding plate A7.1 and a forming part A7.5 thereon. The forming part A7.5 is a partial ring shape. The splicing sliding plate A7.1 includes a sliding tail plate 7.12 with a guiding function and a crescent plate 7.11 at the front end. The sliding tail plate 7.12 is inserted into the chute of the fixed seat block 7.2. The splicing cylinder 7.3 is fixed on the fixed seat block 7.2. The piston rod of the splicing cylinder A7.3 is connected to the ear plate 7.4 on the splicing seat block 7.2. A necking slope 7.53 is arranged on the joint side of the inner wall of the forming part A7.5 and the splicing sliding plate A. A forming half cavity A7.51 is arranged on the forming end face of the forming part A7.5. A transition surface 7.53 is arranged from the necking slope 7.53 to the forming half cavity A7.51. The splicing components A7 are spliced into a complete ring cavity. The cross section of the forming half cavity A7.51 includes a transition arc 7.511, a side wall arc 7.512, a shoulder arc 7.513 and a top arc 7.514.

[0052] Combined with the attached Figures 8-10 The forming die B includes at least two splicing components B10. The splicing component B10 includes a crescent ring B10.1. A guiding slide plate B is arranged on the outer ring wall of the crescent ring B10.1. The guiding ring plate B is inserted into the slot of the fixed seat B10.2. The splicing cylinder B10.3 is fixed on the fixed seat B10.2. The end of the piston rod of the splicing cylinder B10.3 is connected to the ear plate B10.4 on the crescent ring B10.1. The forming part B10.5 is installed on the inner ring of the crescent ring B10.1. The end face of the forming part B10.5 that is spliced with the forming part A7.5 is provided with a forming half-cavity that is mirror-image to the forming half-cavity A7.51.

[0053] Combined with the attached Figures 11-13 The moving seal assembly 4 includes a counterweight seat 4.1. The slider is installed at the bottom of the counterweight seat 4.1. The connecting rod A4.2 is installed at the top of the counterweight seat 4.1. The sealing head A4.3 is installed at the end of the connecting rod A4.2. The sealing head A4.3 is barrel-shaped. A raised sealing ring seat A4.31 is arranged on the outer side of the barrel edge of the sealing head A4.3. Two sealing grooves with different depths are arranged on the sealing ring seat A4.31. A sealing ring 4.34 is installed in the shallow sealing groove. An annular expansion airbag 4.32 is installed in the deep sealing groove. A sealing ring A4.33 is sleeved on the outer side of the expansion airbag 4.32. There is a special air pipe in the support connecting rod cavity connected to the center of the sealing head A4.3 for ventilating the sealing head A4.3.

[0054] Combined with the attached Figure 14 The follow-up seal assembly 13 includes a barrel-shaped sealing head B13.1. The sealing head B13.1 is fixedly installed on the follow-up fixing plate 13.3 through the fixing link 13.2. The follow-up fixing plate 13.3 is fixed on the follow-up frame 3. There is a special air pipe in the fixing link 13.2 for ventilating the sealing head B13.1.

[0055] Combined with the attached Figure 15 The device further includes a pressure system and an electrical control system.

[0056] A processing method for a metal bellows includes the following steps:

[0057] Step 1, feeding: Place the pipe 100 on the arc-shaped material supporting part of the support frame 12 on the machine frame 1. There are rollers on the arc-shaped material supporting part of the support frame 12. The support frame 12 has a lifting function. Push the pipe 100 through the middle holes of the fixed plate A5 and the fixed mold base plate 6; the moving seal assembly 4 operates, moves on the slide rail through the counterweight seat 4.1, drives the seal head A4.3 at the end of the connecting rod A4.2 to move and be inserted into the center of the pipe 100, and determine the relative position of the seal head A4.3 of the moving seal assembly 4 and the seal head B13.1 of the follow-up seal assembly 13 according to the wavelength of the forming wave, and penetrate into the forming mold A; the pressure system 101 is started under the control of the electrical control system 102. The pressure system 101 supplies gas to the expansion airbag 4.32. After the expansion airbag 4.32 expands, it pushes up the sealing ring A4.33 to fit with the inner wall of the pipe 100 to form a seal. The forming mold A on the fixed mold base plate 6 operates, and the forming part A7.5 of the forming mold A is closed under the drive of the splicing cylinder 7.3 to splice into a complete forming mold A; the complete forming mold A and the seal head A4.3 clamp and seal the pipe; a support cylinder 14 is arranged at the center of the fixed plate A5. There is a sealing ring at the inner end of the support cylinder 14. The support cylinder 14 has the functions of support and sealing;

[0058] The displacements of the moving seal assembly 4 and the fixed mold base plate 6 should be the same or have an error of a few millimeters. The main function is to determine the position of the seal head 4.3 of the seal assembly 4 to ensure the wavelength. When the error is greater than 5 mm, the zero position needs to be recalibrated. The method of calibrating the zero position is as follows: Set positioning marks on the machine base 2 and the counterweight seat or connecting rod A of the moving seal assembly 4, which can be positioning pins and positioning holes. After the fixed mold base plate 6 advances to a position greater than the position where the upper and lower limit nuts are inserted, that is, when the maximum gap is reached between the fixed mold base plate 6 and the fixed plate A5, control the position between the seal head B and the seal head A by moving the fixed mold base plate 6 to ensure the wavelength. Insert the upper and lower limit nuts. The upper and lower limit nuts are used to fix the fixed mold base plate. The fixed mold base plate 6 retreats to the upper and lower limit positions and ensures close contact with the upper and lower limit nuts. Record the displacement of the fixed mold base plate 6 at this time, and record this displacement as the position of the zero-point offset to perform zero-point calibration. The upper and lower limit nuts are located on both sides of the fixed mold base plate 6. Different wavelengths can be achieved by adjusting the lengths of the upper and lower limits.

[0059] Step 2, pre-closing the mold: The hydraulic cylinder 15 pushes the moving mold base plate 9 to move. The follower frame 3 fixed on the moving mold base plate 9 moves along with the moving mold base plate 9. The follower seal assembly 13 follows the follower frame 3 and moves together with the moving mold base plate 9. It stops moving when the distance between the moving mold base plate 9 and the fixed mold base plate 6 reaches the set distance. The follower seal assembly 13 moves along with the moving frame 3 and inserts into the interior of the pipe 100. The outer ring of the sealing head B has the same sealing structure as the sealing head A. The pressure system 101 inflates the expansion airbag therein to drive the outer ring seal to expand outwards and seal with the inner wall of the pipe 100. The forming mold B on the moving mold base plate 9 acts. The splicing assembly B10 of the forming mold B is driven by the splicing cylinder B10.1, and the forming part B10.5 is spliced into a complete forming mold B; the complete forming mold B and the sealing head B13.3 of the follower seal assembly 15 clamp and seal the pipe 100; the center of the complete forming mold B is a closed ring;

[0060] Step 3, adopting the axial upsetting forming technology, bending and deforming under the combined action of the axial supply of the mold and the internal pressure: According to the material and wall thickness of the pipe 100, accurately control the pressure inside the sealed section and the axial supply length. When pressurizing, the electrical control system 102 controls the pressure system 101 to pressurize between the sealing head A and the sealing head B from the center of the connecting rod 4.21 of the sealing head A and the fixed connecting rod 13.2. The corresponding position of the pipe 100 is deformed under the action of the internal pressure to achieve the purpose of pre-forming. At the same time, the moving mold base plate 9 moves towards the fixed mold base plate 6 under the push of the hydraulic cylinder 15, realizing the relative movement of the forming mold A and the forming mold B, achieving the purpose of axial feeding. When the forming mold A and the forming mold B are in contact, the forming of one corrugation is completed.

[0061] In order to achieve automation, step 4 can also be added.

[0062] Automatic continuous forming: After the first wave is completed after the molds A and B are closed, the inside of the sealed area is exhausted and depressurized until there is no pressure, and 4.32 and 13.13 are exhausted and depressurized. Then the mold A is split and opened in three parts, and the mold B remains closed. The formed pipe 100 is driven to move backward by the moving template seat 9. Then the expansion airbag 4.32 of the moving seal assembly 4 is filled with low-pressure air, and its function is to fix the formed pipe. Then the mold B is opened in three parts and enters the area to be formed with the follower seal assembly 13 under the drive of the moving template seat 9 to prepare for the next forming. The cyclic operation achieves the purpose of continuous production.

[0063] The above are only the preferred embodiments of the present invention and are not intended to limit the present invention. Any modifications, equivalent replacements, improvements, etc. made within the spirit and principle of the present invention shall be included in the protection scope of the present invention.

Claims

1. An equipment for axial upsetting forming of large-diameter metal bellows, comprising a base (1), characterized in that, The fixed plate A (5) and the fixed plate B (8) are installed on the base (1). The fixed mold base plate (6) and the movable mold base plate (9) are installed between the fixed plate A (5) and the fixed plate B (8). The fixed plate A (5), the fixed plate B (8), the fixed mold base plate (6) and the movable mold base plate (9) all have central holes. The fixed plate B (8), the fixed plate A (5), the fixed mold base plate (6) and the movable mold base plate (9) are connected in series as a whole through the connecting beam columns (11). And the movable mold base plate (9) is slidably installed on the connecting beam columns (11). The piston rod end of the hydraulic cylinder (15) fixed on the fixed plate B (8) is connected to the movable mold base plate (9); The follower frame (3) is fixed on the movable mold base plate (9). The connecting end of the follower seal assembly (13) is fixed on the follower frame (3). The sealing end of the follower seal assembly (13) is located in the central hole of the movable mold base plate (9); The movable seal assembly (4) is installed on the base (1) through a slider and a slide rail; The forming mold A is installed around the central hole on the fixed mold base plate (6). The forming mold B is installed around the central hole on the movable mold base plate (9); The forming mold A consists of at least two splicing components A (7); The splicing component A (7) includes a splicing sliding plate A (7.1) and a forming part A (7.5) thereon. The forming part A (7.5) is a partial ring shape. The splicing sliding plate A (7.1) includes a sliding tail plate (7.12) for guiding and a crescent plate (7.11) at the front end. The sliding tail plate (7.12) is inserted into the chute of the fixed seat block (7.2). The splicing cylinder A (7.3) is fixed on the fixed seat block (7.2). The piston rod of the splicing cylinder A (7.3) is connected to the ear plate (7.4) on the splicing sliding plate A (7.1); A necking slope (7.53) is arranged on the inner wall of the forming part A (7.5) at the joint side with the splicing sliding plate A. A forming half cavity A (7.51) is arranged on the forming end face of the forming part A (7.5). A transition surface (7.53) is arranged from the necking slope (7.53) to the forming half cavity A (7.51); The forming mold B includes at least two splicing components B (10). The splicing component B (10) includes a crescent ring B (10.1). A guiding sliding plate B is arranged on the outer ring wall of the crescent ring B (10.1). The guiding ring plate B is inserted into the slot of the fixed seat B (10.2). The splicing cylinder B (10.3) is fixed on the fixed seat B (10.2). The end of the piston rod of the splicing cylinder B (10.3) is connected to the ear plate B (10.4) on the crescent ring B (10.1). A forming part B (10.5) is installed on the inner ring of the crescent ring B (10.1). A forming half cavity that is mirror-image to the forming half cavity A (7.51) is arranged on the end face of the forming part B (10.5) that is spliced with the forming part A (7.5); The moving sealing assembly (4) includes a counterweight seat (4.1), a slider is installed at the bottom of the counterweight seat (4.1), a connecting rod A (4.2) is installed at the top of the counterweight seat (4.1), and a sealing head A (4.3) is installed at the end of the connecting rod A (4.2). The sealing head A (4.3) is in a barrel shape, and a raised sealing ring seat A (4.31) is arranged on the outer side of the barrel edge of the sealing head A (4.3). Two sealing grooves with different depths are arranged on the sealing ring seat A (4.31). A sealing ring (4.34) is installed in the shallow sealing groove, and an annular expansion airbag (4.32) is installed in the deep sealing groove. A sealing ring A (4.33) is sleeved on the outer side of the expansion airbag (4.32). The follow-up sealing assembly (13) includes a barrel-shaped sealing head B (13.1), and the sealing head B (13.1) is fixedly installed on the follow-up fixing plate (13.3) through a fixing link (13.2).

2. The equipment for axial upsetting forming of large-diameter metal bellows according to claim 1, characterized in that, The splicing assembly A (7) splices into a complete annular cavity.

3. The equipment for axial upsetting forming of large-diameter metal bellows according to claim 1 or 2, characterized in that, The cross-section of the formed half-cavity A (7.51) includes a transition arc (7.511), a side wall arc (7.512), a shoulder arc (7.513) and a top arc (7.514).

4. The equipment for axial upsetting forming of large-diameter metal bellows according to claim 3, characterized in that, The equipment also includes a pressure system (101) and an electrical control system (102).

5. A processing method for metal bellows using the equipment described in claim 4, characterized in that, It includes the following steps: Step 1, loading: Place the pipe (100) on the arc-shaped material supporting part of the supporting frame (12) on the base (1). There are rollers on the arc-shaped material supporting part of the supporting frame (12). Push the pipe (100) through the middle holes of the fixing plate A (5) and the fixed mold base plate (6). The moving sealing assembly (4) acts, and moves on the slide rail through the counterweight seat (4.1), drives the sealing head A (4.3) at the end of the connecting rod A (4.2) to move and be inserted into the center of the pipe (100), and penetrates to the formed mold A. The formed mold A on the fixed mold base plate (6) acts, and the forming part A (7.5) of the formed mold A is closed under the drive of the splicing cylinder A (7.3) to splice into a complete formed mold A. The complete formed mold A and the sealing head A (4.3) clamp and seal one end of the pipe (100). Step 2, pre-closing the mold: The hydraulic cylinder (15) pushes the moving mold base plate (9) to move. The follow-up sealing assembly (13) moves together with the moving mold base plate (9). When the distance between the moving mold base plate (9) and the fixed mold base plate (6) reaches the set distance, it stops moving. The formed mold B on the moving mold base plate (9) acts, and the splicing assembly B (10) of the formed mold is driven by the splicing cylinder B (10.3), and the forming part B (10.5) is spliced into a complete formed mold B. The complete formed mold B and the sealing head B (13.1) of the follow-up sealing assembly (13) clamp and seal the other end of the pipe (100). Step 3, bending and forming under the combined action of the die and internal pressure: After the die A, die B, and the corresponding moving seal assembly (4) and follower seal assembly (13) move to the set positions, a sealed cavity is formed between the tube blank and the seal assembly. An inert gas greater than the yield pressure of the tube blank is filled into the interior of the tube blank, causing the material in the deformation zone of the tube blank to yield and undergo bending deformation. Under the support of the forming internal pressure, the hydraulic cylinder (15) is used to push the moving die base plate (9), the forming die B on the moving die base plate (9), and the follower seal assembly (13) to move together, providing axial feed to cause the sealed part of the tube blank to undergo bending deformation and gradually conform to the die cavity formed by die A and die B until the dies are fully closed. The sealed part of the tube blank completes the final die fitting under the action of the bending force provided by the moving die and the forming internal pressure. Forming is carried out by the method of applying pressure while axially supplying until the dies are closed. According to the material and wall thickness of the pipe material (100), the pressure inside the sealed section, the die closing speed, and the axial supply length are controlled.

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