Forming system and forming method for large-port tubular parts

Abstract

This invention provides a forming system and method for large-port tubular parts. The forming system includes a heating device, a flaring punch, and a hydraulic forming die arranged sequentially. The heating device is used to locally heat the tube blank. The flaring punch, located after the heating device, includes a flaring section, a sealing section, and a connecting section. The diameter of the flaring section gradually increases from one end to the other. The sealing section is located on the outer wall of the flaring section. The connecting section is installed on one end of the flaring section and connected to a hydraulic system. At least one cooling water channel is provided inside the flaring section, and liquid from the hydraulic system flows into the cooling water channel. The hydraulic forming die, located after the flaring punch, is used to hydraulically form the tube blank. This invention utilizes electromagnetic induction heating and a hydraulic forming die to improve the local plasticity of the material through localized direct heating and forming, while also optimizing the stress state and reducing the risk of fracture.

Description

Technical Field

[0001] This invention relates to the field of automobile manufacturing technology, and in particular to a molding system and method for large-port tubular parts. Background Technology

[0002] In the field of automotive manufacturing technology, tubular parts, with their closed cross-section, have higher bending and torsional stiffness, as well as better strength and fatigue performance compared to open parts. Therefore, they have become the main solution for lightweighting automotive structures and are widely used in body and chassis structural components.

[0003] like Figure 1 As shown, taking the chassis subframe as an example, its front and rear crossbeams and trailing arms are often designed as tubular structures. In order to ensure sufficient rigidity, strength and durability, it is necessary to ensure that the overlap area between the crossbeam and the trailing arm has a sufficiently long overlap line A.

[0004] Currently, tubular parts are mainly produced using hydroforming technology. The basic process is as follows: First, the tube blank is pre-bent using a tube bending machine. Then, it is placed into a hydroforming mold, and both ends of the tube blank are sealed using a sealing punch, while liquid is injected into the tube. Finally, under the pressure of the internal liquid, the tube blank is forced to conform to the mold cavity, forming the desired shape.

[0005] However, conventional hydroforming processes have certain limitations. The ends of the formed tubular parts need to be further processed using independent flaring equipment and special molds, and due to the limitation of material elongation, the flaring rate of the end circumference is usually no more than 15%. This limitation often makes it difficult to meet the actual use requirements of the product, resulting in the need to add additional reinforcing patches in the overlapping area to improve the overall performance during production.

[0006] Based on the above description, the current forming methods and apparatus for large-port tubular parts have the following technical shortcomings: 1. Flaring the ends of tubular parts at room temperature using a flaring machine and flaring mold: Due to the limitation of material elongation, the flaring ratio of the end circumference of tubular parts usually does not exceed 15%, and the end shape of tubular parts is also constrained. This limits the freedom of end shape design and may not meet certain performance requirements.

[0007] 2. Add heating elements to the hydraulic forming mold and flare the part after local heating: The part is heated by heat conduction. The heat provided by the heating element is transferred to the part through the mold. This method of indirect heating of the part has low heating efficiency, and repeated heating and cooling of the mold will affect the strength and life of the mold itself.

[0008] In view of this, the inventors of this application have designed a forming system and method for large-port tubular parts in order to overcome the above-mentioned technical problems. Summary of the Invention

[0009] The technical problem to be solved by the present invention is to overcome the limitations of existing forming methods and devices for large-port tubular parts in terms of end flaring rate, heating efficiency and forming quality, and to provide a forming system and forming method for large-port tubular parts.

[0010] The present invention solves the above-mentioned technical problems through the following technical solution: A forming system for a large-port tubular part is characterized in that the forming system includes a heating device, a flaring punch, and a hydraulic forming die arranged sequentially. The heating device is used to locally heat the tube blank. The flaring punch is arranged in the production line after the heating device and includes a flaring section, a sealing section, and a connecting section. The diameter of the flaring section gradually increases from one end to the other end, and is used to expand the end of the tube blank. The sealing section is disposed on the outer wall surface of the flaring section and is used to seal the end of the tube blank. The connecting section is installed on one end of the flaring section and connected to a hydraulic system for introducing hydraulic fluid. At least one cooling water channel is provided in the flaring section, and the fluid in the hydraulic system flows into the cooling water channel to cool the flaring punch. The hydraulic forming die is arranged in the production line after the flaring punch and is used to hydraulically form the tube blank.

[0011] According to one embodiment of the present invention, the heating device is an electromagnetic induction coil.

[0012] According to one embodiment of the present invention, the electromagnetic induction coil includes: a conductive coil, a power supply, and a control system. The conductive coil is connected to the control system, and the control system is externally connected to the power supply. The control system is used to adjust the frequency, amplitude, and operating time of the current.

[0013] According to one embodiment of the present invention, the conductive coil is made of a highly conductive material.

[0014] According to one embodiment of the present invention, the sealing portion protrudes outward along the outer wall surface of the flared portion, forming a protrusion.

[0015] According to one embodiment of the present invention, the hydraulic forming mold includes an upper mold and a lower mold, the upper mold and the lower mold being fixed on an upper mold base and a lower mold base respectively, and the inner sides of the upper mold and the lower mold being respectively provided with cavities for accommodating the tube blank to be formed.

[0016] The present invention also provides a method for forming a large-port tubular part, characterized in that the forming method employs the forming system for large-port tubular parts as described above, and the forming method includes the following steps: S1. Locally heat the end of the tube blank to soften the end of the tube blank; S2. Place the heated tube blank into a hydraulic forming mold; S3. The hydraulic forming mold seals and flares the ends of the tube blank.

[0017] According to one embodiment of the present invention, step S1 includes: using an electromagnetic coil for non-contact local direct heating, thereby causing the local temperature of the tube blank to rise.

[0018] According to one embodiment of the present invention, the end temperature of the tube blank in step S1 is raised to 500°C to 600°C.

[0019] According to one embodiment of the present invention, step S3 includes: using a punch to feed the end of the tube blank towards the middle of the tube blank along the axial direction, wherein the punch applies axial and radial pressure on both sides of the tube blank.

[0020] The positive and progressive effects of this invention are as follows: The present invention relates to a forming system and method for large-port tubular parts, which utilizes electromagnetic induction heating and hydraulic forming molds to improve the local plasticity of the material through local direct heating and forming, while also optimizing the stress state and reducing the risk of fracture. Attached Figure Description

[0021] The above and other features, properties and advantages of the present invention will become more apparent from the following description taken in conjunction with the accompanying drawings and embodiments, in which the same reference numerals always denote the same features, wherein: Figure 1 This is a schematic diagram of the structure of a hydroformed tube beam subframe in the prior art.

[0022] Figure 2 This is a schematic diagram of the electromagnetic induction coil in the forming system of the large-port tubular part of the present invention.

[0023] Figure 3 This is a schematic diagram of the flaring punch in the forming system of the large-port tubular part of the present invention.

[0024] Figure 4 This is a schematic diagram of the hydraulic forming mold in the forming system of the large-port tubular part of the present invention.

[0025] [Attached image labels]

[0026] Connection line A

[0027] Heating device 10

[0028] 20 flaring punch

[0029] 30 hydraulic forming mold

[0030] Conductive coil 11

[0031] Power supply 12

[0032] Control System 13

[0033] Flaring part 21

[0034] Sealing part 22

[0035] Connecting part 23

[0036] Cooling water circuit 24

[0037] Upper mold 31

[0038] Lower mold 32

[0039] Cavity 33

[0040] 34 Inlays Detailed Implementation

[0041] The present invention will be further described below with reference to specific embodiments and accompanying drawings. More details are set forth in the following description in order to provide a full understanding of the present invention. However, the present invention can obviously be implemented in many other ways different from those described herein. Those skilled in the art can make similar extensions and derivations based on actual application situations without departing from the spirit of the present invention. Therefore, the scope of protection of the present invention should not be limited by the content of this specific embodiment.

[0042] Embodiments of the invention will now be described in detail with reference to the accompanying drawings. It should be noted that these and subsequent drawings are merely illustrative and are not drawn to scale, and should not be construed as limiting the scope of the invention. Wherever possible, the same reference numerals will be used in all drawings to denote the same or similar parts.

[0043] Furthermore, although the terminology used in this invention is selected from commonly known and used terms, some terms mentioned in this specification may have been selected by the applicant in his or her judgment, and their detailed meanings are explained in the relevant sections of the description herein.

[0044] Furthermore, the invention should be understood not only through the actual terminology used, but also through the meaning implied by each term.

[0045] This invention discloses a forming system for large-port tubular parts, comprising: a heating device 10, a flaring punch 20, and a hydraulic forming die 30. The heating device 10 is used for localized heating of the tubular blank. The flaring punch 20 is arranged in the production line following the heating device 10 and is used to seal and expand the end of the locally heated tubular blank. The hydraulic forming die 30 is arranged in the production line following the flaring punch 20 and is used for hydraulically forming the expanded tubular blank.

[0046] like Figure 2 As shown, the heating device 10 is preferably an electromagnetic induction coil. The electromagnetic induction coil is used to achieve localized heating of the metal. The electromagnetic induction coil is preferably made of a highly conductive material (such as a hollow copper tube) and is directly connected to a high-frequency AC power supply. Once the power supply is turned on, a high-frequency AC current will rapidly form inside the coil and continue to conduct.

[0047] As a high-frequency current passes through, a high-intensity and rapidly alternating electromagnetic field is generated around and inside the coil. This magnetic field changes periodically at an extremely fast speed and propagates outward. The high-frequency characteristics of the current play a decisive role in the entire induction heating process: when a conductive workpiece is placed in this alternating magnetic field, the high-frequency magnetic field, according to the law of electromagnetic induction, instantly generates a powerful closed-loop induced current, or "eddy current," within the metal workpiece. These eddy currents generate Joule heating by overcoming the metal's own resistance, thus efficiently achieving localized heating of the metal.

[0048] Preferably, the electromagnetic induction coil includes: a conductive coil 11, a power supply 12, and a control system 13. The conductive coil 11 is connected to the control system 13, and the control system 13 is externally connected to the power supply 12. The control system 13 is used to adjust the frequency, amplitude, and working time of the current.

[0049] As the core component of the electromagnetic induction coil, the conductive coil 11 is typically made of high-quality, highly conductive materials (such as copper or aluminum) and precisely wound. Its physical shape can be designed as circular, elliptical, or other specific geometric shapes according to actual working conditions and heating requirements. During operation, the conductive coil 11 can generate strong eddy currents inside the metal target object through the principle of electromagnetic induction, thereby achieving precise local heating of a specific area. For specific applications of heating the pipe beam ends before hydroforming, a relatively simple single-layer coil can fully meet the requirements. In addition, to ensure the safety and stability of equipment operation, the coil is usually wrapped with insulating materials, such as plastics, ceramics, or other materials with excellent insulation properties, to effectively prevent inter-turn short circuits or other electrical faults from occurring inside the coil.

[0050] The electromagnetic induction coil uses an external power supply 12 to provide a high-frequency oscillating current to generate a changing magnetic field. The electromagnetic induction coil is equipped with an independent integrated control system 13, which can adjust the electromagnetic induction heating parameters according to specific heating requirements.

[0051] like Figure 3 As shown, the flaring punch 20, as a key tool in the hydroforming process, not only performs the function of precisely flaring the end of the tube beam, but also plays an important role in reliably sealing the tube blank during the forming process. To achieve this dual function, the core of the flaring punch 20 is specially designed with a through-tube for transmitting the emulsion required for hydroforming, thereby providing a stable high-pressure medium for the plastic deformation of the tube blank.

[0052] Preferably, the flaring punch 20 is precisely assembled from three main parts: a flaring section 21, a sealing section 22, and a connecting section 23. The flaring section 21 is the core component that directly contacts the workpiece, primarily used to forcibly expand the end of the tube blank to achieve the preset diameter or shape requirements. The sealing section 22 is tightly installed on the outer wall of the flaring section 21, and its core function is to tightly seal the end opening of the tube blank during high-pressure liquid injection, preventing emulsion leakage and ensuring the smooth operation of the hydroforming process within a completely closed cavity.

[0053] The connecting part 23 is securely mounted on one end of the flared part 21. It serves as a connecting hub directly connected to the hydraulic system, primarily responsible for introducing hydraulic fluid to apply the internal pressure required for molding. In actual assembly, the flaring punch 20 preferably uses a threaded connection or other reliable mechanical connection method to achieve a secure and sealed connection with the hydraulic system.

[0054] During the flaring process at the end of the pipe, the high-temperature end of the pipe blank inevitably generates a large amount of heat, which is continuously conducted to the flaring punch 20 in contact with it. To cope with this heat load, at least one cooling water channel 24 is precisely opened in the internal structure of the flaring section 21. The cooling water channel 24 carries away excess heat through circulating cooling medium, efficiently cooling the flaring punch 20, thereby effectively preventing the sealing part from deforming or being damaged due to excessive temperature caused by prolonged heating, ensuring the stability of the entire forming process and the long service life of the sealing component.

[0055] Here, when designing the structure of the flared section 21, it is necessary to fully consider the flow and deformation characteristics of the tube during the plastic deformation process to ensure that the tube blank does not generate uneven stress distribution or local stress concentration during the complex bulging process, thereby effectively avoiding forming defects such as excessive thinning of the tube wall, wrinkling or even cracking.

[0056] Therefore, specialized stress analysis methods (such as finite element numerical simulation) are typically required to deeply analyze the material stress state throughout the bulging process. Based on these precise analysis results, the most reasonable punch geometry (such as taper angle and shoulder radius) and optimal process control parameters are derived in reverse. This design method, guided by theoretical analysis, not only fundamentally ensures the feasibility and production safety of the billet end bulging process but also precisely controls the forming quality, ensuring that the final product achieves the ideal geometric shape and dimensional accuracy that meets design expectations.

[0057] In terms of specific structure, the specific design of the flared section 21 is closely related to and complements the implementation of the segmented flaring process. In the precision structural design of the mold, the geometry of the end of the flaring punch 20 must be rigorously calculated to ensure that its outline can perfectly match the final required "flared mouth" forming outline.

[0058] In actual operation, the end position and feed rate of the flaring punch 20 are subject to high-precision automated control. During the first flaring stage, the flaring punch 20 only contacts the first pre-defined "forming area" at the tube end, precisely driving the material in that area to undergo plastic deformation, initially reaching the predetermined contour line position. Then, in the second flaring stage, the flaring punch 20 continues to feed along a predetermined trajectory, contacting subsequent new "forming areas" and completing the deformation of the remaining portion. Through the precise fit between the end of the flaring punch 20 and the mold cavity, and the accurate control of the punch's forward position, it is ensured that each action is strictly confined to the target segmented area for forming.

[0059] This process strategy successfully discretizes the originally uncontrollable overall free deformation into several controllable staged deformations, thereby greatly improving the stability of the molding process and effectively ensuring the dimensional accuracy and contour consistency of the final product.

[0060] Preferably, the sealing part 22 is structurally designed to protrude outward along the outer wall surface of the flared part 21, thereby forming a significant protrusion. Throughout the entire hydroforming process, the flaring punches 20 located at both ends of the pipe are key components ensuring the formation of a sealed cavity inside the pipe, effectively guaranteeing that the forming medium will not leak even under extremely high hydraulic pressure.

[0061] To meet this stringent sealing requirement, a rubber sealing ring or similar elastic sealing device is specially configured at the part of the flared punch 20 that directly contacts the end of the tube blank. This design utilizes the compression and rebound characteristics of elastic materials to form a tight interference fit between the punch and the tube, thereby ensuring that the contact interface can effectively block liquid and achieve a highly efficient and reliable sealing effect.

[0062] The flaring punch 20 is typically precision-manufactured from special materials with high wear resistance and excellent corrosion resistance to ensure its long-term durability and operational reliability under harsh working conditions. In existing conventional technologies, the function of the flaring punch 20 is often relatively simple, mainly limited to providing basic sealing and performing routine bulging operations.

[0063] However, in this application, in order to perfectly adapt to the advanced segmented flaring process, the flaring punch 20 is configured as a precision composite punch structure. Specifically, the flaring punch 20 adopts a nested collaborative working mode, that is, a blanking punch is cleverly fitted around the outer periphery of the flaring punch 20, and the two cooperate with each other.

[0064] This unique composite structure endows the equipment with entirely new process capabilities: during the flaring operation, the system can first perform precise stamping and flaring using the flaring punch 20, and then use the outer pressing punch to firmly press and fix the tube blank, simultaneously completing the sealing action. This structural design, which separates the "flaring" and "pressing" functions in structure but highly coordinates their actions, is the core key to realizing complex segmented and intermittent flaring processes, and is a technological advantage that traditional single-function flaring punches cannot match or possess.

[0065] like Figure 4 As shown, the hydraulic forming mold 30 is a key component used in the hydraulic forming process. The hydraulic forming mold 30 mainly consists of two parts: an upper mold 31 and a lower mold 32. In actual assembly, the upper mold 31 and the lower mold 32 are securely installed and fixed on the upper mold base and the lower mold base, respectively, thus forming a complete mold assembly.

[0066] To achieve precise plastic deformation of the tube blank, the inner sides of both the upper mold 31 and the lower mold 32 are precision-machined, each equipped with a cavity 33 that perfectly matches the shape of the workpiece. When the molds are closed, the upper and lower cavities 33 together form a closed space specifically designed to accommodate and constrain the tube blank to be formed. The upper mold 31 and lower mold 32 must achieve extremely high precision during mold closing; this is not only to prevent leakage of high-pressure liquid but also crucial to ensuring that the workpiece can be accurately formed along a predetermined trajectory. The specific geometry and dimensions of the cavity 33 depend entirely on the design requirements of the final workpiece, ensuring a high degree of consistency from mold to finished product.

[0067] Because the pipe fitting ends need to be flared under high-temperature heating, the molds face severe thermal wear challenges over a long period, thus requiring significantly improved wear resistance and thermal stability. To effectively address this condition and reduce maintenance costs, a modular design approach is typically adopted in engineering. The mold at the end, which directly experiences high temperatures and intense friction, is designed as an independent insert 34, precisely embedded within the overall mold base. This structural design allows for the replacement of only the insert 34 after it wears down due to long-term service, greatly simplifying subsequent maintenance and replacement procedures.

[0068] In terms of material selection and manufacturing process, hydroforming molds 30 typically use high-quality tool steel or cemented carbide as the base material to ensure sufficient strength and toughness. Furthermore, a special wear-resistant coating (such as nitriding, PVD / CVD coating, etc.) is applied to the mold surface. Through the perfect combination of base material and surface strengthening technology, the service life and overall performance of the mold under harsh working conditions are comprehensively ensured.

[0069] The present invention also provides a method for forming a large-port tubular part, which adopts the forming system for large-port tubular parts as described above. Before hydraulic forming, the end of the tube blank is locally heated by an electromagnetic induction coil, and then placed in a hydraulic forming mold. The end punch seals the tube blank while the port is expanded.

[0070] The molding method includes the following steps: Step S1: Locally heat the end of the tube blank to soften the end of the tube blank.

[0071] Preferably, step S1 includes: using an electromagnetic coil for non-contact localized direct heating, thereby raising the local temperature of the tube blank. The end temperature of the tube blank rises to 500°C to 600°C.

[0072] Using an electromagnetic coil can rapidly raise the temperature of the tube blank end to 500℃ to 600℃, increasing the tube blank end circumference by 30%, without excessive thinning or cracking of the end material, thus greatly improving the formability of the parts.

[0073] First, non-contact, localized direct heating is achieved using an electromagnetic coil. Through the principle of electromagnetic induction heating, eddy currents are generated in specific areas of the tube blank, causing localized heating. Over time, the temperature of the metal tube blank gradually increases until the desired heating temperature is reached. At high temperatures, the metal's strength and hardness decrease significantly, while its plasticity increases.

[0074] Here, electromagnetic induction heating is a non-contact heating method. An electromagnetic coil generates a high-frequency alternating current, which produces a changing magnetic field. When a metallic object is placed in this changing magnetic field, eddy currents are generated inside the metal according to Faraday's law of electromagnetic induction. The direction and magnitude of these currents depend on the shape of the metallic object, its conductivity, and the rate of change of the magnetic field. As these eddy currents flow inside the metallic object, they encounter resistance and generate Joule heat. This is because the resistance causes current loss, and the lost electrical energy is converted into heat energy, causing the metallic object to heat up. This heating of the metallic object is a result of electromagnetic induction heating.

[0075] Over time, the temperature of a metallic object gradually rises until it reaches the required heating temperature. At high temperatures, the strength and hardness of the metal decrease significantly, while its plasticity increases. This is because atoms move more easily at high temperatures, and grain rearrangement is more likely to occur.

[0076] It should be understood that electromagnetic coil induction heating is not the only local heating method used in this application. Effective local heating methods employing the principles and methods of this invention should share the common characteristic of achieving rapid, uniform, and regionally controllable heating. For example, local heating using lasers at specific frequencies can theoretically be applied, but conductive heating or heating methods that cannot precisely control the area are not suitable.

[0077] Step S2: Place the heated tube blank into a hydraulic forming mold.

[0078] Step S3: The hydraulic forming mold seals and flares the ends of the tube blank.

[0079] Preferably, step S3 includes: using a punch to feed the end of the tube blank towards the middle of the tube blank along the axial direction, wherein the punch applies axial and radial pressure on both sides of the tube blank.

[0080] After the end of the tube blank is locally heated, the heated tube blank is then placed into a hydraulic forming mold. The flaring punches on both sides have the functions of sealing and flaring the tube blank, and simultaneously complete the sealing and flaring of the end of the tube blank before hydraulic forming. As the punches feed towards the middle of the tube blank along the axial direction at the end of the tube blank, the flaring punches 21 apply axial and radial pressure on both sides of the tube blank. This causes the tube end material to be subjected to pressure in two directions, and the tube end material is in a stress state of two compressions and one tension, which reduces the possibility of material fracture and cracking.

[0081] Based on the above description of the structure and method, the forming system and method for large-port tubular parts of the present invention have the following characteristics: 1. Localized Direct Heating: The magnetic field generated by the electromagnetic coil acts directly on the end of the tube blank, generating heat. This means that only a portion of the tube blank is directly heated and formed, rather than the entire tube blank. Because it is localized direct heating and forming, the heating area can be precisely controlled, so that only the necessary parts are heated, saving energy and improving efficiency.

[0082] II. Non-contact heating: Electromagnetic induction heating is a non-contact heating method that does not require direct contact with the tube blank, which can reduce wear and contamination, and also avoid material deformation or damage.

[0083] Third, utilizing the properties of metals at high temperatures: At high temperatures, the strength and hardness of metals decrease significantly, while their plasticity increases. This is because at high temperatures, atoms move more easily, and grain rearrangement occurs more readily, making the metal easier to shape.

[0084] IV. Wide applicability: Electromagnetic coil induction heating is not the only local heating method in this application. As long as the billet can be locally heated to improve the local plasticity of the material, it can be applied to the technical solution of this application.

[0085] V. Simple forming process: The partially heated tube blank is placed into the hydraulic forming mold. The punches at both ends have the functions of tube blank sealing and flaring, and at the same time complete the tube blank sealing and end flaring before hydraulic forming.

[0086] VI. Optimize stress state: The force applied to the end of the tube blank by the flaring punch is both axial and radial pressure, which makes the material at the end of the tube in a stress state of two compressions and one tension. The equivalent yield stress value is low, which reduces the possibility of material fracture and cracking.

[0087] In summary, the forming system and method for large-port tubular parts of the present invention utilize electromagnetic induction heating and hydraulic forming molds to improve the local plasticity of the material through local direct heating and forming, while also optimizing the stress state and reducing the risk of fracture.

[0088] For those skilled in the art, the above disclosure is merely illustrative and does not constitute a limitation of this application. Although not explicitly stated herein, those skilled in the art may make various modifications, improvements, and corrections to this application. Such modifications, improvements, and corrections are suggested in this application and therefore remain within the spirit and scope of the exemplary embodiments of this application.

[0089] It should be noted that the use of terms such as "first" and "second" to define components is merely for the purpose of distinguishing the corresponding components. Unless otherwise stated, the above terms have no special meaning and therefore should not be construed as limiting the scope of protection of this application.

[0090] Furthermore, this application uses specific terms to describe embodiments of the application. For example, "an embodiment," "one embodiment," and / or "some embodiments" refer to a particular feature, structure, or characteristic related to at least one embodiment of the application. Therefore, it should be emphasized and noted that "an embodiment," "one embodiment," or "an alternative embodiment" mentioned twice or more in different locations in this specification do not necessarily refer to the same embodiment. In addition, certain features, structures, or characteristics in one or more embodiments of the application can be appropriately combined.

[0091] Similarly, it should be noted that, in order to simplify the description of the embodiments disclosed in this application and thus aid in the understanding of one or more embodiments of the invention, the foregoing description of the embodiments of this application sometimes combines multiple features into a single embodiment, drawing, or description thereof. However, this disclosure method does not imply that the subject matter of this application requires more features than those mentioned in the claims. In fact, the embodiments have fewer features than all the features of the single embodiments disclosed above.

[0092] Accordingly, in some embodiments, the numerical parameters used in the specification and claims are approximate values, which may be changed depending on the characteristics required by individual embodiments. In some embodiments, the numerical parameters should take into account specified significant digits and employ a general method of digit preservation. Although the numerical ranges and parameters used to confirm their breadth of application in some embodiments of this application are approximate values, in specific embodiments, such values ​​are set as precisely as feasible.

[0093] While specific embodiments of the present invention have been described above, those skilled in the art should understand that these are merely illustrative examples, and the scope of protection of the present invention is defined by the appended claims. Those skilled in the art can make various changes or modifications to these embodiments without departing from the principles and essence of the present invention, but all such changes and modifications fall within the scope of protection of the present invention.

Claims

1. A forming system for a large-port tubular part, characterized in that, The forming system for the large-port tubular part includes a heating device, a flaring punch, and a hydraulic forming die arranged in sequence. The heating device is used to locally heat the tube blank. The flaring punch is arranged in the production line after the heating device and includes a flaring section, a sealing section, and a connecting section. The diameter of the flaring section gradually increases from one end to the other end, and is used to expand the end of the tube blank. The sealing section is disposed on the outer wall surface of the flaring section and is used to seal the end of the tube blank. The connecting section is installed on one end of the flaring section and is connected to the hydraulic system for introducing hydraulic fluid. At least one cooling water channel is opened in the flaring section, and the fluid in the hydraulic system flows into the cooling water channel to cool the flaring punch. The hydraulic forming die is arranged in the production line after the flaring punch and is used to hydraulically form the tube blank.

2. The forming system for large-port tubular parts as described in claim 1, characterized in that, The heating device is an electromagnetic induction coil.

3. The forming system for large-port tubular parts as described in claim 2, characterized in that, The electromagnetic induction coil includes: a conductive coil, a power supply, and a control system. The conductive coil is connected to the control system, and the control system is externally connected to the power supply. The control system is used to adjust the frequency, amplitude, and operating time of the current.

4. The forming system for large-port tubular parts as described in claim 3, characterized in that, The conductive coil is made of a highly conductive material.

5. The forming system for large-port tubular parts as described in claim 1, characterized in that, The sealing part protrudes outward along the outer wall surface of the flared part, forming a protrusion.

6. The forming system for large-port tubular parts as described in claim 1, characterized in that, The hydraulic forming mold includes an upper mold and a lower mold, which are fixed on an upper mold base and a lower mold base, respectively. The inner sides of the upper mold and the lower mold are respectively provided with cavities for accommodating the tube blank to be formed.

7. A method for forming a large-port tubular part, characterized in that, The forming method employs the forming system for large-port tubular parts as described in any one of claims 1-6, and the forming method includes the following steps: S1. Locally heat the end of the tube blank to soften the end of the tube blank; S2. Place the heated tube blank into a hydraulic forming mold; S3. The hydraulic forming mold seals and flares the ends of the tube blank.

8. The method for forming a large-port tubular part as described in claim 7, characterized in that, Step S1 includes: using an electromagnetic coil for non-contact local direct heating, thereby causing the local temperature of the tube blank to rise.

9. The method for forming a large-port tubular part as described in claim 8, characterized in that, In step S1, the end temperature of the tube blank is raised to 500°C to 600°C.

10. The method for forming a large-port tubular part as described in claim 7, characterized in that, Step S3 includes: using a punch to feed the end of the tube blank towards the middle of the tube blank along the axial direction, and the punch applying axial and radial pressure on both sides of the tube blank.

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