Electromagnetic impact hydraulic forming apparatus and method for a tubular

Abstract

The application belongs to the field of hydraulic forming of pipe fittings, and specifically discloses an electromagnetic impact hydraulic forming device and method for pipe fittings. After the relative spatial positions of the pipe fitting, the driving plate and the punch are uniquely designed, the same driving coil simultaneously generates axial electromagnetic forces on the driving plate and the high-conductivity metal pipe fitting at the upper end, respectively, the axial electromagnetic force generated on the driving plate further generates internal fluid pressure inside the pipe fitting, radial expansion of the pipe fitting is realized, the axial electromagnetic force generated at the end of the high-conductivity metal pipe fitting further generates an axial feeding force at the end of the pipe fitting, axial material flow is realized, and the coordinated high-speed driving of the radial expansion of the pipe fitting and the axial material flow effectively suppresses the problem of the thinning of the wall thickness of the pipe fitting. Since the internal pressure supply system and the end feeding control system are removed, the problem that the existing traditional pipe fitting hydraulic forming technology relies on an internal hydraulic power source and an external control system and that it is difficult to match and control the internal pressure and the axial feeding is solved.

Description

Technical Field

[0001] The present application belongs to the field of hydraulic forming of pipe fittings, and more specifically, relates to an electromagnetic impact hydraulic forming device and method for pipe fittings. Background Art

[0002] Tube hydroforming is a plastic forming technology that uses high-pressure liquid to deform metal tubes within a closed mold. Currently, the main forming process is high-pressure tube hydroforming technology. However, this process requires large presses and complex pressure sealing systems, which will increase manufacturing costs, extend the forming cycle, and reduce production efficiency. In addition, the sole reliance on high internal pressure will increase the interface friction between the tube and the mold, severely restricting the flow of metal tube material, and subjecting the workpiece to biaxial tensile stress, which will lead to severe thickness thinning and even cracking. Coupled with the limited forming limit of lightweight alloys at room temperature, these challenges further exacerbate the difficulty of forming tubular components.

[0003] To this end, researchers at home and abroad have proposed the use of low-pressure hydraulic forming to improve the problem of excessively high forming pressure. Studies have shown that the internal pressure and clamping force during the low-pressure hydraulic forming process of pipe fittings have indeed been significantly reduced, and the wall thickness distribution is more uniform, without excessive thinning. However, due to the assembly gap between the sharp corners of the closed mold and the pipe fittings, the sharp corners are prone to plastic deformation, and their outer surfaces will wear under the action of friction. In addition, the low-pressure hydraulic forming method involves matching control between the internal pressure support system and the clamping displacement clamping system, which poses the risk of wrinkling and buckling. The forming process involves steps such as pressurization, clamping, and pressure relief, resulting in a relatively long forming cycle.

[0004] In addition, in order to promote material flow and suppress excessive thinning in the hydroforming of pipe fittings, the axial hydraulic forging sequential forming method developed in recent years can achieve low thinning rate and double-step forming of aluminum alloy reducer pipes through multi-stage compression under the support of internal pressure. However, these methods require a reasonable combination of pressure and feed parameters, and involve complex multi-step operations in the pipe hydroforming process. The manufacturing process is relatively more, and the forming speed is low, which is not conducive to the efficient forming and manufacturing of thin-walled or complex tubular components.

[0005] To solve the above problems, the patent CN109622718B proposes an electromagnetic forming and hydraulic forming composite process. The workpiece to be processed is an aluminum alloy pipe with a thickness of 2 mm and a diameter of 30 mm. The mold is connected to the lower part of the body. The edge pressing coil is sleeved at the lower end of the columnar structure and placed inside the body, and located at the upper part of the pipe to be formed. The edge pressing coil is placed at the lower part of the pipe to be formed. During the forming process, the edge pressing coil and the edge pressing coil act simultaneously. On the one hand, it can avoid the ejection of the pipe during the forming process, and more importantly, it can further provide axial electromagnetic force to the pipe to the mold, so as to obtain better forming effect of the sample. However, this technology has the following defects and deficiencies: on the one hand, the coil at the end of the pipe is embedded in the liquid cavity, and the safety is poor when the strong pulse current (up to 20 kA) in the coil is discharged, and it is very difficult to implement the tooling; on the other hand, the electromagnetic impact source is applied in the radial direction, and the volume of the liquid cavity at the upper end is too large, which easily leads to insufficient liquid pressure, and thus the forming precision is poor, and the coordination between the radial driving coil and the axial pushing coil is poor, which easily leads to the problem of pipe wrinkling. SUMMARY

[0006] To overcome the defects of the prior art, the purpose of the present application is to provide an electromagnetic impact hydraulic forming device and method for pipe, which aims to solve the problems of poor plasticity, high sealing requirement, easy breakage and poor forming precision in traditional pipe hydraulic forming.

[0007] To achieve the above purpose, in a first aspect, the present application provides an electromagnetic impact hydraulic forming device for pipe, comprising: a magnetic drive discharge circuit, a driving coil, a driving plate, a driving punch, a mold, a sealing punch;

[0008] The driving punch and the sealing punch form a sealing cavity for containing liquid medium;

[0009] The mold is located outside the pipe to be processed, and the bottom of the mold and the bottom end of the pipe are located on the same horizontal line, for constraining the pipe forming;

[0010] The upper surface of the punch is fixedly connected with the driving plate;

[0011] The driving plate, the driving punch and the sealing punch have equal diameters and are adapted to the inner diameter of the pipe to be processed, so as to form a sliding fit;

[0012] The driving coil has a planar spiral structure and is located above the driving plate, for generating electromagnetic force on the driving plate and the upper end of the pipe after the magnetic drive discharge circuit applies a strong pulse current.

[0013] Preferably, the driving coil is divided into an inner layer, an intermediate layer and an outer layer outward from the axis, and is reinforced by 2 mm, 1 mm and 0.5 mm thick Chailong fibers respectively.

[0014] Preferably, it also includes: an upper end support member for fixing the driving coil; a lower end support member located outside the upper end support member and making the entire forming device coaxial, for supporting the entire forming device to prevent it from shaking left and right.

[0015] Preferably, an epoxy pad is provided at the upper end of the mold to fix the pipe to be processed and prevent the upper end of the pipe from being plastically deformed due to radial electromagnetic force.

[0016] Preferably, the upper surface of the driving plate is approximately level with the upper end surface of the pipe to be processed, with an error of no more than ±0.5 mm.

[0017] Preferably, sealing rings are embedded at both ends of the driving punch and the sealing punch to prevent liquid leakage.

[0018] Preferably, the mold is a left-right split structure made of stainless steel.

[0019] Preferably, a high conductivity driving copper ring is added to the top of the pipe to be processed, and the conductivity of the high conductivity driving copper ring is higher than , the inner and outer diameters are the same as those of the pipe to be processed.

[0020] To achieve the above-mentioned objectives, in a second aspect, the present application provides an electromagnetic impact hydraulic forming method for a pipe fitting, which is applied to the electromagnetic impact hydraulic forming device as described in the first aspect, and the method comprises:

[0021] Assembly of the pipe to be processed: placing the pipe to be processed into the processed forming mold;

[0022] Filling of forming medium: After filling the cavity with water, add the sealing punch and then seal the hole in the center of the driving plate with screws;

[0023] A strong pulse current is passed into the driving coil through the magnetic drive discharge circuit, thereby generating axial electromagnetic forces on the driving plate and the upper end of the pipe to be processed.

[0024] Preferably, before the strong pulse current is applied, the initial relative position between the driving plate and the upper end portion of the pipe to be processed is changed, thereby adjusting the electromagnetic feed force acting on the pipe end.

[0025] In general, the above technical solutions conceived by this application have the following beneficial effects compared with the existing technologies:

[0026] (1) This application proposes an electromagnetic impact hydraulic forming device for pipe fittings. After a unique design of the relative spatial positions of the pipe fitting, the drive plate, and the punch, an axial electromagnetic force is generated simultaneously on the drive plate and the upper end of the high-conductivity metal pipe fitting through the same drive coil. The axial electromagnetic force generated on the drive plate generates internal fluid pressure inside the pipe fitting, thereby achieving radial expansion of the pipe fitting. The axial electromagnetic force generated at the end of the high-conductivity metal pipe fitting generates an axial feed force at the end of the pipe fitting, thereby achieving axial material flow. The coordinated high-speed drive of the radial expansion of the pipe fitting and the axial material flow effectively suppresses the problem of thinning and cracking of the pipe fitting wall. By removing the internal pressure supply system and the feed control system at the end of the existing hydraulic forming device, the problem of difficult control of internal pressure and axial feed matching in the existing traditional pipe fitting hydraulic forming technology, which relies on the internal hydraulic power source and external control system, is solved.

[0027] (2) This application proposes an electromagnetic impact hydraulic forming method for pipe fittings. This method adopts an axial unilateral asymmetric structural loading method, simplifies the forming device and process flow, and integrates the advantages of high strain rate deformation, dynamic fluid pressure, and strong material fluidity. It has the characteristics of fast forming speed, good coordination between the internal fluid pressure of the pipe fitting and the axial material flow, and can significantly improve the plasticity and wall thickness distribution uniformity of the pipe fitting. It is expected to provide important technical support for high-performance forming manufacturing in the fields of aerospace, automobiles, etc.

[0028] (3) This application proposes a method for electromagnetic impact hydraulic forming of pipe fittings based on a high-conductivity metal drive ring, which uses a drive coil to simultaneously generate electromagnetic force on a drive plate and a metal drive ring. The electromagnetic force on the drive plate is used to compress the liquid to generate fluid pressure to cause the pipe fitting to undergo radial expansion, while the electromagnetic force on the drive ring is used to drive the low-conductivity metal pipe fitting to undergo axial material flow. This method is suitable for forming and manufacturing both high-conductivity and low-conductivity high-strength metal pipe fittings, solving the problem that electromagnetic forming methods are difficult to apply to the processing of low-conductivity metal pipe fittings, and has the advantages of high flexibility and good adaptability. BRIEF DESCRIPTION OF THE DRAWINGS

[0029] Figure 1 This is a structural schematic diagram of an electromagnetic impact hydraulic forming device for pipe fittings provided in an embodiment of the present application.

[0030] Figure 2 This is a schematic diagram of the layered reinforcement method used for the drive coil provided in the embodiment of the present application.

[0031] Figure 3 This is a schematic diagram of the system discharge circuit for electromagnetic impact hydraulic forming of pipe fittings provided in an embodiment of the present application.

[0032] Figure 4 This is a schematic diagram of the generation of bidirectional electromagnetic force provided in an embodiment of the present application.

[0033] Figure 5 This is a schematic diagram of regulating the axial electromagnetic force at the end of a pipe provided in an embodiment of the present application.

[0034] Figure 6 These are the experimental and simulation results of electromagnetic impact hydraulic forming of aluminum alloy pipe fittings provided in the embodiments of the present application, where (a) is the forming profile under different coil discharge voltages; (b) is the die gap under different coil discharge voltages.

[0035] Figure 7 This is the electromagnetic force distribution in the electromagnetic impact hydraulic forming of aluminum alloy pipes provided in an embodiment of the present application, wherein (a) is the axial electromagnetic force on the driving plate under different coil discharge voltages; (b) is the axial electromagnetic force on the end of the pipe under different coil discharge voltages.

[0036] Figure 8 3. The diagram of the electromagnetic impact hydraulic forming coil and mold device for low-conductivity material pipe fittings provided in an embodiment of the present application, wherein (a) is a three-dimensional experimental device diagram; (b) is a two-dimensional experimental device diagram.

[0037] Throughout the drawings, the same reference numerals are used to denote the same elements or structures, wherein:

[0038] 1-1 is a pulse capacitor, 1-2 is a diode, 1-3 is a freewheeling resistor, 1-4 is a line resistor, 1-5 is a line inductor, 2-1 is a coil skeleton, 2-2 is a driving coil, 2-3 is an upper epoxy resin support, 2-4 is a driving plate, 2-5 is a driving punch, 2-6 is an epoxy pad, 2-7 is a punch sealing ring, 2-8 is a mold, 2-9 is a lower end support, 2-10 is a pipe to be processed, 2-11 is a liquid medium, 2-12 is a sealing punch sealing ring, 2-13 is a sealing punch, 3-1 is a high conductivity driving ring, and 3-2 is a low conductivity metal pipe. DETAILED DESCRIPTION

[0039] In order to make the purpose, technical solutions and advantages of this application more clear, the following further describes this application in detail with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are only used to explain this application and are not intended to limit this application.

[0040] The embodiments of the present application are described below in conjunction with the drawings in the embodiments of the present application.

[0041] like Figure 1 As shown, the present application proposes an electromagnetic impact hydraulic forming device for pipe fittings, including a magnetic drive discharge circuit, a drive coil 2-2, a drive plate 2-4, a drive punch 2-5, a die 2-8, and a sealing punch 2-13;

[0042] The driving punch 2-5 and the sealing punch 2-13 form a sealing chamber for containing a liquid medium 2-11;

[0043] The mold 2-8 is used to constrain the forming of the pipe. It is placed outside the pipe to be processed, and its bottom and the bottom end of the pipe are on the same horizontal line, so as to ensure that the pipe is deformed into the desired target formed part.

[0044] The upper surface of the punch 2-5 is fixedly connected to the driving plate 2-4;

[0045] The diameters of the driving plate 2-4, the driving punch 2-5 and the sealing punch 2-13 are equal and matched with the inner diameter of the pipe 2-10 to be processed (the error does not exceed ±0.2mm), thereby forming a sliding fit;

[0046] The driving coil is a planar spiral structure coil located above the driving plate 2-4 and is used to generate electromagnetic force on the driving plate and the end of the pipe at the same time after a strong pulse current is applied to the magnetic drive discharge circuit.

[0047] Preferably, if Figure 2 As shown, the drive coil utilizes a layered reinforcement method to ensure mechanical stability under high current and strong magnetic field conditions. Specifically, the inner, middle, and outer layers are reinforced with 2 mm, 1 mm, and 0.5 mm thick Chailong fiber, respectively. The drive coil is wound on a coil bobbin 2-1, which is made of epoxy resin. The distance between the drive coil and the drive plate is 1 mm to 3 mm. The smaller the distance, the greater the electromagnetic force.

[0048] The external support includes: an upper epoxy resin support 2-3 for fixing the drive coil; a lower support 2-9 for supporting the entire forming device to prevent it from shaking. At the same time, 2-9 is located on the outside of 2-3 to ensure that the entire forming device is located at the same center of a circle.

[0049] Preferably, an epoxy pad 2-6 is provided at the upper end of the mold 2-8 for fixing the pipe to be processed to prevent the upper end of the pipe from being plastically deformed due to radial electromagnetic force.

[0050] Preferably, the driving plate is approximately level with the end face of the pipe to be processed, specifically, the error does not exceed ±0.5 mm.

[0051] Preferably, the driving plates 2 - 4 are made of high conductivity materials, including but not limited to: being cut from copper materials.

[0052] Preferably, sealing rings 2-7 are embedded at both ends of the driving punch and the bottom sealing punch to prevent liquid leakage.

[0053] The mold is preferably made of 304 stainless steel and has a split left and right structure to facilitate disassembly of the pipe after forming. During the experiment, it is assembled with bolts. To reduce the interference of air on the forming accuracy, a 2 mm diameter exhaust port is reserved in the chamfer area of ​​the mold.

[0054] Preferably, a drainage hole is provided in the center of the driving plate to drain excess liquid before forming, and the liquid in the pipe is sealed by bolts; after forming is completed, the bolts are removed to relieve the pressure inside the pipe, and the pipe is taken out.

[0055] like Figure 3 As shown, the magnetic drive discharge circuit includes a pulse capacitor 1-1 for storing electrical energy, a diode 1-2 connected in parallel with a freewheeling resistor 1-3 to reduce coil temperature rise, and line resistance 1-4 and line inductance 1-5, essential circuit components generated by the high current flowing through the circuit. The discharge system also includes a charger, a pulse capacitor, and a thyristor switch for generating and controlling the strong pulse current. The coil current generated in the magnetic drive system flows into the electromagnetic coil, generating electromagnetic forces on the drive plate and the end of the pipe, causing plastic deformation of the pipe. During the experiments, the entire forming device was secured under a hydraulic press to prevent displacement caused by electromagnetic reaction forces during discharge. Due to the short discharge time, a Rogowski coil was used to measure the strong pulse current in the forming coil.

[0056] The basic principle of electromagnetic impact hydraulic forming of pipe fittings in this application is as follows Figure 4 As shown, a strong pulse current is passed through the driving coil to generate a pulse electromagnetic force, which includes an electromagnetic driving force acting on the driving plate. F zd and electromagnetic feed force acting on the end of the pipe F zt In this configuration, the electromagnetic driving force F zd As the main impact force, it is responsible for generating high-speed fluid pressure, while the electromagnetic feed force F zt This electromagnetic force field coordination mechanism enables synchronous regulation of internal fluid pressure and axial material feeding during the pipe hydroforming process.

[0057] Based on the above, this application proposes an electromagnetic impact hydroforming method for pipe fittings, comprising:

[0058] Assembly and fixation of the pipe to be processed: Place the pipe to be processed into the processed forming die 2-8. The gap between the outer diameter of the pipe and the die is about 0.2mm to prevent the pipe from shaking during the forming process.

[0059] Filling the forming medium: first fill the liquid cavity with water, then add the sealing punch, and finally seal the hole in the center of the driving plate with screws to ensure that water does not leak;

[0060] A strong pulse current is passed into the driving coil through the magnetic drive discharge circuit, and axial electromagnetic forces are generated on the driving plate and the upper end of the high-conductivity metal pipe respectively.

[0061] The unidirectional drive coil loading method can simplify packaging and save manufacturing costs. For a single pipe, this application is a one-time impact forming.

[0062] When the forming device is in operation, the driving coil is connected to the pulse power supply; the mold is placed outside the pipe to be formed to constrain the shape of the workpiece to be formed; then the sealing punch at the lower end of the pipe is embedded to prevent liquid leakage, and then the liquid medium is injected; after the liquid cavity is filled with liquid, the electromagnetic punch at the upper end of the pipe is embedded into the interior of the pipe, and then the bolts are tightened to seal the liquid cavity to prevent liquid leakage; during forming, the electromagnetic driving force on the electromagnetic driving plate quickly impacts the forming medium, the high-speed impact body compresses the liquid to form fluid pressure acting on the pipe to be formed, and the electromagnetic feed force generated on the end of the pipe drives the pipe to generate axial material flow, and under the synergistic effect of the fluid pressure inside the pipe and the axial electromagnetic feed force, the pipe to be formed is deformed until it fits the mold; after the forming is completed, the sealing bolt at the center of the electromagnetic punch at the upper end of the pipe is unscrewed, thereby removing the fluid pressure inside the pipe and leaking the liquid, and at the same time, the bolts of the forming mold are removed, the formed pipe is taken out, and the above-mentioned electromagnetic impact hydraulic forming steps are repeated to prepare for the next electromagnetic impact bulging of the pipe.

[0063] Preferably, before the strong pulse current is applied, the relative position between the driving plate and the end of the pipe is changed, thereby adjusting the electromagnetic feed force acting on the pipe end.

[0064] like Figure 5 As shown, when the relative position P r =0 mm, the tube end is subjected to a stronger electromagnetic feeding force generated by the forming coil F zt On the contrary, when P r =20 mm, the electromagnetic feeding force on the tube end is significantly reduced. In general, the magnetic force decays exponentially with increasing distance between the forming coil and the metal material. This method achieves synchronous loading and adjustable control of the electromagnetic driving force and feed force, providing an effective means for force regulation during the forming process.

[0065] Example 1

[0066] In this embodiment, the total number of turns of the drive coil is 40. The thickness and diameter of the drive plate are 7 mm and 76 mm, respectively. The diameter and length of the aluminum alloy pipe are 80 mm and 180 mm, respectively. The mold is made of stainless steel, and the radial forming space is 12 mm. The drive punch is made of aluminum.

[0067] like Figure 6 As shown in Figure 2, in order to improve the forming accuracy and suppress excessive thinning of the tube at the same time, the discharge voltage can be continuously increased under the experimental condition that the driving plate and the tube end are at the same horizontal position to achieve this goal. The results of the bulging experiment and numerical simulation show that with the increase of the discharge voltage, the die fitting clearance gradually decreases, as shown in Figure 2. Figure 6 Specifically, when the coil voltage increases from 5 kV to 8 kV, the maximum die fit gap can be reduced from 6.9 mm to only 0.18 mm, as shown in (a). Figure 6 As shown in (b). And, Figure 7 The numerical analysis results of the axial electromagnetic force on the driving plate and the end of the pipe show that when the relative position is zero, increasing the discharge voltage will enhance the axial electromagnetic force acting on the driving plate and the pipe end, thereby improving the forming accuracy and inhibiting the thinning of the pipe wall thickness, which will help to significantly improve the forming performance of the aluminum alloy reducer.

[0068] The coil current needs to be more than 12 kA, and a layered reinforcement structure is used to ensure the reliable and safe operation of the coil; in one embodiment provided in this application, the outer diameter of the coil is about 120 mm, and a 4x10 turn coil is used. In order to ensure one-time impact forming or achieve pipe forming with stronger metal strength and greater deformation, a large-size multi-layer and multi-turn electromagnetic coil with a larger coil size and more turns can be used to generate a greater pulse electromagnetic force.

[0069] Example 2

[0070] For some metal pipes made of low conductivity materials, such as titanium alloy, stainless steel and magnesium alloy and other high strength pipes, use Figure 1 The electromagnetic impact hydroforming device shown above cannot generate sufficient axial electromagnetic force at the end of the tube to drive axial movement. Therefore, for low-conductivity metal tubes, a high-conductivity metal drive ring can be added to the end of the tube. The electromagnetic driving force induced on the drive ring can drive the low-conductivity metal tube to flow in the axial direction.

[0071] like Figure 8 As shown, the present application provides an electromagnetic impact hydraulic forming device applicable to low conductivity metal pipes, which is Figure 1 The main difference is that a high conductivity driving copper ring 3-1 with a height of 5 mm (higher than the ), the inner diameter and outer diameter of the high conductivity driving copper ring 3-1 are the same as those of the pipe to be processed, and the other components are the same as Figure 1 Similarly, when a strong pulse current is passed through the coil, a strong pulse electromagnetic force is generated on the drive plate and the high-conductivity drive ring 3-1. The low-conductivity metal pipe undergoes plastic deformation under the action of the internal liquid pressure and the electromagnetic driving force of the drive ring, thereby achieving synchronous regulation of the pipe's radial expansion and axial material flow.

[0072] In this application, the terms "first" and "second" are used to distinguish different objects, rather than to describe a specific order of objects. For example, the terms "first response message" and "second response message" are used to distinguish different response messages, rather than to describe a specific order of response messages.

[0073] The term "electrical connection" in this application can be a direct circuit connection or signal transmission through a communication protocol.

[0074] In the embodiments of this application, words such as "exemplary" or "for example" are used to indicate examples, illustrations, or descriptions. Any embodiment or design described as "exemplary" or "for example" in the embodiments of this application should not be interpreted as being preferred or advantageous over other embodiments or designs. Rather, the use of words such as "exemplary" or "for example" is intended to present the relevant concepts in a concrete manner.

[0075] In the description of the embodiments of the present application, unless otherwise specified, "multiple" means two or more, for example, multiple processing units means two or more processing units, etc.; multiple elements means two or more elements, etc.

[0076] It should be understood that expressions such as "include" and "may include" used in this application indicate the existence of the disclosed functions, operations, or constituent elements, and do not limit one or more additional functions, operations, and constituent elements. In this application, terms such as "include" and / or "have" may be interpreted as indicating specific characteristics, numbers, operations, constituent elements, components, or combinations thereof, but may not be interpreted as excluding the existence or possibility of adding one or more other characteristics, numbers, operations, constituent elements, components, or combinations thereof.

[0077] In addition, in this application, the expression "and / or" includes any and all combinations of the associated listed words. For example, the expression "A and / or B" may include A, may include B, or may include both A and B.

[0078] In the description of the embodiments of the present application, it should be noted that, unless otherwise clearly specified and limited, the term "connection" should be understood in a broad sense. For example, "connection" can be a detachable connection or a non-detachable connection; it can be a direct connection or an indirect connection through an intermediate medium. Among them, "fixed connection" means that the two are connected to each other and the relative position relationship after the connection remains unchanged. "Rotational connection" means that the two are connected to each other and can rotate relative to each other after the connection. "Sliding connection" means that the two are connected to each other and can slide relative to each other after the connection. The directional terms mentioned in the embodiments of the present application, such as "top", "bottom", "inside", "outside", "left", "right", etc., are only reference to the directions of the accompanying drawings. Therefore, the directional terms used are for better and clearer explanation and understanding of the embodiments of the present application, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as a limitation on the embodiments of the present application.

[0079] In addition, in the embodiments of the present application, the mathematical concepts mentioned include symmetry, equality, parallelism, and perpendicularity. These limitations are all for the current state of the art, rather than being absolutely strict definitions in a mathematical sense. A small amount of deviation is allowed, and it is possible to be approximately symmetric, approximately equal, approximately parallel, or approximately perpendicular. For example, A and B are parallel, which means that A and B are parallel or approximately parallel, and the angle between A and B can be between 0 and 10 degrees. A and B are perpendicular, which means that A and B are perpendicular or approximately perpendicular, and the angle between A and B can be between 80 and 100 degrees.

[0080] The above description is merely a specific embodiment of the present application, but the scope of protection of the present application is not limited thereto. Any changes or substitutions that can be easily conceived by a person skilled in the art within the technical scope disclosed in this application should be included in the scope of protection of the present application. Therefore, the scope of protection of the present application should be based on the scope of protection of the claims.

Claims

1. An electromagnetic impact hydraulic forming device for pipe fittings, characterized in that: include: Magnetic drive discharge circuit, drive coil, drive plate, drive punch, die, sealing punch; The driving punch and the sealing punch form a sealing chamber for containing a liquid medium; The mold is located outside the pipe to be processed, and its bottom and the bottom of the pipe are on the same horizontal line, which is used to constrain the forming of the pipe; The upper surface of the punch is fixedly connected to the driving plate; The driving plate, the driving punch and the sealing punch have equal diameters and are adapted to the inner diameter of the pipe to be processed, thereby forming a sliding fit; The driving coil is a planar spiral structure located above the driving plate. It is used to generate electromagnetic force on the driving plate and the upper end of the pipe at the same time after a strong pulse current is applied to the magnetic drive discharge circuit.

2. The electromagnetic impact hydraulic forming device according to claim 1, characterized in that: The driving coil is divided into inner layer, middle layer and outer layer from the axis outward, and is reinforced with Chailong fiber with thickness of 2mm, 1mm and 0.5mm respectively.

3. The electromagnetic impact hydraulic forming device according to claim 1, characterized in that: Also includes: The upper end support is used to fix the driving coil; the lower end support is located on the outside of the upper end support and makes the entire forming device coaxial, and is used to support the entire forming device to prevent it from shaking left and right.

4. The electromagnetic impact hydraulic forming device according to claim 1, characterized in that: An epoxy pad is provided at the upper end of the mold to fix the pipe to be processed and prevent the upper end of the pipe from plastic deformation due to radial electromagnetic force.

5. The electromagnetic impact hydraulic forming device according to claim 1, characterized in that: The upper surface of the driving plate is approximately level with the upper end surface of the pipe to be processed, with an error of no more than ±0.5mm.

6. The electromagnetic impact hydraulic forming device according to claim 1, characterized in that: Sealing rings are embedded at both ends of the driving punch and the sealing punch to prevent liquid leakage.

7. The electromagnetic impact hydraulic forming device according to claim 1, characterized in that: The mold adopts a left and right split structure made of stainless steel.

8. The electromagnetic impact hydraulic forming device according to any one of claims 1 to 7, characterized in that: A high conductivity driving copper ring is added to the top of the pipe to be processed. The conductivity of the high conductivity driving copper ring is higher than , the inner and outer diameters are the same as those of the pipe to be processed.

9. A method for electromagnetic impact hydraulic forming of pipe fittings, characterized in that: Applied to the electromagnetic impact hydraulic forming device according to any one of claims 1 to 8, the method comprises: Assembly of the pipe to be processed: placing the pipe to be processed into the processed forming mold; Filling the forming medium: After filling the cavity with water, add the sealing punch and then seal the hole in the center of the driving plate with screws; A strong pulse current is passed into the driving coil through the magnetic drive discharge circuit, thereby generating axial electromagnetic forces on the driving plate and the upper end of the pipe to be processed.

10. The electromagnetic impact hydroforming method according to claim 9, wherein: Before the strong pulse current is applied, the initial relative position between the driving plate and the upper end of the pipe to be processed is changed, thereby adjusting the electromagnetic feed force acting on the pipe end.

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