Machining device and method for light high-strength high-modulus anti-fatigue pull rod

Abstract

According to the machining device and method for the light high-strength high-modulus anti-fatigue pull rod, an inductance coil is installed outside a ceramic mold in a sleeving mode, and a screw arranged in a threaded hole in the center of an installation flange is embedded into the center of the installation end of the ceramic mold in a sleeving mode; a space cavity formed by the inner surface of the ceramic mold and the screw is used as a forming structure of a pipe blank forming end; in the process of extruding and forming the end part of the single side of the pipe blank, an alternating magnetic field is generated by an inductance coil to carry out induction heating on the pipe blank entering a large-diameter closing area in the ceramic mold, and the water-based graphite on the outer sides of a thick-wall area and a transition area of the pipe blank firstly forms a dry film; and the thick wall area and the transition area of the pipe blank are continuously and sequentially extruded into the large-diameter closing-in area, the equal-diameter stability increasing area and the small-diameter closing-in area, and extrusion forming of the single-side end of the pipe blank is achieved. According to the method, the problem that hollow fusiform products such as pull rods cannot be formed by the aluminum-based composite material through a traditional cold rotary swaging or hot extrusion process due to the fact that the reinforcement phase proportion of the aluminum-based composite material is increased is solved.

Description

Technical Field

[0001] This invention relates to, but is not limited to, the field of plastic processing technology, and particularly to a processing device and method for lightweight, high-strength, high-modulus, fatigue-resistant tie rods. Background Technology

[0002] A type of tubular component is frequently used in aircraft control and lift systems. This component is characterized by its thin outer diameter and thick walls at both ends, a thick outer diameter and thin walls in the middle, a hollow interior, and a spindle-shaped appearance. Internal threads are typically machined into the thicker walls at both ends. This type of component is lightweight, high-strength, and resistant to tension, compression, torsion, and bending. It can withstand both static and dynamic loads during use. Because these components are commonly used for flight attitude control and directly impact flight safety, they are often defined as critical or important components.

[0003] Given the enclosed cavity structure of the aforementioned parts, traditional machining methods cannot reach the inner surfaces. Plastic forming can more easily achieve the desired part properties, typically using hot extrusion (hot extrusion) or cold forging (cold forging). Hot extrusion is generally used for forming tie rods from aluminum alloy tubing, while cold forging is generally used for forming tie rods from aluminum alloy and stainless steel tubing. However, with advancements in materials science and changes in tie rod operating conditions, the low modulus, low strength, and poor fatigue resistance of aluminum alloys, and the high density and high inertia of stainless steel, no longer meet the service requirements for lightweight, high-strength, high-modulus, and fatigue-resistant components.

[0004] Aluminum-based composites, with their lightweight, high strength, high modulus, and fatigue resistance, have been applied in high-end manufacturing fields such as aerospace and precision instruments, and are also very suitable as an upgraded replacement material for tubular parts. As the reinforcing ratio of aluminum-based composites increases, the mechanical properties of the material become increasingly superior, but this is accompanied by a sharp decrease in thermal conductivity and plasticity, making it impossible to use traditional processes (cold forging or hot extrusion) to form hollow shuttle-shaped products such as tie rods. Summary of the Invention

[0005] The purpose of this invention is to solve the above-mentioned technical problems. The embodiments of this invention provide a processing device and method for lightweight, high-strength, high-modulus, fatigue-resistant tie rods, in order to solve the problem that aluminum-based composites cannot be formed into hollow shuttle-shaped products such as tie rods by traditional cold forging or hot extrusion processes due to the increased proportion of reinforcing phases.

[0006] The technical solution of the present invention: The present invention provides a processing device for lightweight, high-strength, high-modulus, fatigue-resistant tie rods, including: a top block 1, a clamping block 11, an inductor coil 4, and a mold assembly, wherein the main structure of the mold assembly is a ceramic mold 3; The tube blank 17 to be formed is clamped by the clamping block 11 installed on the side push plate of the machine tool so as to keep the tube blank 17 stably coaxial with the ceramic mold 3 during the processing; the top block 1 installed on the tailstock of the machine tool presses against the non-forming end of the tube blank 17. The inductor coil 4 is sleeved and installed outside the ceramic mold 3. The ceramic mold 3 is fixedly installed on the machine head of the equipment by the mounting flange 5. The screw 6 set in the central threaded hole of the mounting flange 5 is embedded and sleeved in the center of the mounting end of the ceramic mold 3. It is used as the forming structure of the forming end of the tube blank 17 through the space cavity formed by the inner surface of the ceramic mold 3 and the screw 6. The internal working cavity of the ceramic mold 3 is sequentially configured along the forming direction as a large-diameter taper area 12, an equal-diameter stabilizing area 13, and a small-diameter taper area 15; wherein, the inner diameter of the starting end of the large-diameter taper area 12 is larger than the outer diameter of the end of the tube blank 17. The forming device is used to generate an alternating magnetic field 10 through an inductor coil 4 to induction heat the tube blank 17 entering the large-diameter narrowing zone 12 in the ceramic mold 3 during the extrusion forming of one side of the tube blank 17. The thick-walled zone 20 of the tube blank 17 and the water-based graphite outside the transition zone 19 first form a dry film. Through the continuous feeding of the ceramic mold 3, the thick-walled zone 20 and the transition zone 19 of the tube blank 17 are continuously and sequentially extruded into the large-diameter narrowing zone 12, the equal-diameter stabilizing zone 13 and the small-diameter narrowing zone 15, thereby realizing the extrusion forming of one side of the tube blank 17.

[0007] Optionally, in the forming device for a lightweight, high-strength, high-modulus, fatigue-resistant tie rod as described above, the mold assembly includes: a ceramic mold 3, a mounting flange 5, screws 6, rubber gaskets 7, a metal ring 8, and a core rod 9; The ceramic mold 3 is configured as a columnar structure with a hollow working cavity. An aramid fiber layer 14 is formed on the outside of the ceramic mold 3 by curing. The tail end of the ceramic mold 3 is fixedly installed to the mounting flange 5 by screws 6. A core rod 9 is installed in the central threaded hole of the mounting flange 5. An inductor coil 4 is sleeved on the outside of the aramid fiber layer 14 of the ceramic mold 3.

[0008] Optionally, in the forming apparatus for a lightweight, high-strength, high-modulus, fatigue-resistant tie rod as described above, the mold assembly further includes: a rubber pad 7; One end of the mounting flange 5 is provided with an annular boss to form a mounting seat for the ceramic mold 3. One end of the ceramic mold 3 is embedded in the mounting seat formed by the annular boss, and a rubber gasket 7 is provided between the contact end face of the mounting flange 5 and the ceramic mold 3 to prevent the ceramic mold 3 from being squeezed and cracked.

[0009] Optionally, in the forming device for a lightweight, high-strength, high-modulus, fatigue-resistant tie rod as described above, the mold assembly further includes: a metal ring 8; The cylindrical outer wall of the ceramic mold 3 and the mounting flange 5 is provided with an annular mounting slot 16. Two semi-circular metal rings 8 are installed in the annular mounting slot 16. The annular boss of the mounting flange 5 is pressed radially onto the metal rings 8 of the annular mounting slot 16 of the ceramic mold 3 by multiple screws 6 to prevent the ceramic mold 3 from being squeezed and cracked.

[0010] Optionally, in the forming apparatus for a lightweight, high-strength, high-modulus, fatigue-resistant tie rod as described above, The ceramic mold 3 is prepared as follows: ceramic material is formed into a ceramic mold 3 blank by slip casting. After the ceramic mold 3 blank is sintered, its working area and annular mounting slot 16 are polished so that the working area reaches a smoothness of not less than Ra0.1 and the annular mounting slot 16 reaches a smoothness of not less than Ra1.6. Then, an aramid fiber layer 14 is wrapped around the outside of the polished ceramic mold 3 blank and bonded and cured with the ceramic mold 3 blank to form the ceramic mold 3.

[0011] Secondly, embodiments of the present invention also provide a method for processing a lightweight, high-strength, high-modulus, fatigue-resistant tie rod, comprising: using a forming apparatus for a lightweight, high-strength, high-modulus, fatigue-resistant tie rod as described in any of the preceding claims to process the tie rod; Step 1: Prepare a tube blank 17 with a wall thickness in the middle that is smaller than that at both ends. Roughen the ends of the tube blank 17 and make the inner hole in the middle of the tube blank 17 of equal diameter. Step 2: Install the tube blank 17 and adjust the position of the ceramic mold 3 and the tube blank 17 using the equipment to extrude and form one side of the tube blank 17. Step 3: Demold the tube blank 17 that has been extruded on one side. Step 4: Repeat steps 1 to 3 to process the other end of the tube blank 17.

[0012] Optionally, in the processing method of a lightweight, high-strength, high-modulus, fatigue-resistant tie rod as described above, step 1 includes: The outer wall of the thick-walled aluminum composite tube is machined to form a dumbbell-shaped tube blank 17 with a wall thickness of less than that of the thick-walled regions 20 at both ends in the middle thin-walled region 18. The thick-walled regions 20 and transition regions 19 at both ends of the tube blank 17 are roughened by turning, and water-based graphite lubricant is coated on the roughened areas.

[0013] Optionally, in the processing method of a lightweight, high-strength, high-modulus, fatigue-resistant tie rod as described above, step 2 includes: Step 21: Place the equipment in the initial state, clamp the tube blank 17 with the clamping block 11, and after the top block 1 moves from the initial position along the axial direction to the end face of the non-forming end of the tube blank 17, apply a counter-pushing force, and adjust the position of the ceramic mold 3 on the machine head of the equipment so that the ceramic mold 3 coincides with the central axis of the tube blank 17. Step 22: Start the inductor coil 4 to generate an alternating magnetic field 10. The die head drives the ceramic mold 3 to slowly move towards the tube blank 17 until the forming end of the tube blank 17 enters the large diameter narrowing zone 12. The tube blank 17 is induced heated by the alternating magnetic field 10. The thick-walled region 20 of the tube blank 17 and the water-based graphite outside the transition zone 19 first form a dry film. The ceramic mold 3 continues to feed the tube blank 17, so that the thick-walled region 20 and the transition zone 19 of the tube blank 17 are continuously and sequentially squeezed into the large diameter narrowing zone 12, the constant diameter stabilization zone 13 and the small diameter narrowing zone 15. When the thin-walled region 18 of the tube blank 17 enters the constant diameter stabilization zone 13, the inductor coil 4 stops being energized. When the ceramic mold 3 is fed to the theoretical position, the tube blank 17 completes the extrusion forming process.

[0014] Optionally, in the processing method of a lightweight, high-strength, high-modulus, fatigue-resistant tie rod as described above, step 3 includes: The top block 1 retracts to the initial position, the machine head carrying the ceramic mold 3 retracts to the initial position, the two semi-circular clamping blocks 11 open, and the pull rod 2, which has completed the single-sided end extrusion forming, is taken out.

[0015] Optionally, in the processing method of a lightweight, high-strength, high-modulus, fatigue-resistant tie rod as described above, step 4 includes: Step 41, forming and installing the other end of the tube blank 17, includes: placing the equipment in the initial state, clamping the tube blank 17 by the clamping block 11, moving the top block 1 from the initial position along the axial direction to contact the end face of the tube blank 17 after the closed end is contacted, and applying a counter-thrust force, adjusting the position of the ceramic mold 3 on the equipment head so that the ceramic mold 3 coincides with the central axis of the tube blank 17. Step 42: Activate inductor coil 4 to generate alternating magnetic field 10. The die head drives ceramic mold 3 to slowly move towards tube blank 17 until the forming end of tube blank 17 enters the large-diameter narrowing zone 12. Tube blank 17 is induced heated by alternating magnetic field 10. The thick-walled region 20 of tube blank 17 and the water-based graphite outside the transition zone 19 first form a dry film. Ceramic mold 3 continues to feed tube blank 17. The thick-walled region 20 and the transition zone 19 of tube blank 17 are continuously and sequentially extruded into the large-diameter narrowing zone 12, the constant-diameter stabilization zone 13, and the small-diameter narrowing zone 15. When the thin-walled region 18 of tube blank 17 enters the constant-diameter stabilization zone 13, inductor coil 4 stops being energized. When ceramic mold 3 is fed to the theoretical position, tube blank 17 completes the extrusion forming process. Step 43: Top block 1 retracts to the initial position, the machine head carrying ceramic mold 3 retracts to the initial position, the two semi-circular clamping blocks 11 open, and the pull rod 2, which has been extruded and formed on both sides, is taken out.

[0016] The beneficial effects of this invention: This invention provides a processing apparatus and method for lightweight, high-strength, high-modulus, fatigue-resistant tie rods. During the extrusion forming process of one side of the tube blank 17, an alternating magnetic field 10 generated by an inductor coil 4 induction heats the tube blank 17 within the large-diameter narrowing zone 12 of the ceramic mold 3. A dry film is first formed between the thick-walled region 20 of the tube blank 17 and the water-based graphite outside the transition zone 19. Through continuous feeding of the ceramic mold 3, the thick-walled region 20 and the transition zone 19 of the tube blank 17 are continuously and sequentially extruded into the large-diameter narrowing zone 12, the constant-diameter stabilization zone 13, and the small-diameter narrowing zone 15, thus achieving extrusion forming of one side of the tube blank 17. The processing technology solution for lightweight, high-strength, high-modulus, fatigue-resistant tie rods provided by this invention has the following beneficial effects: First, the high-strength, high-modulus, fatigue-resistant tie rod processing solution provided by the present invention improves the plasticity of aluminum-based composite tube blank by electromagnetic induction heating. During the heating process, the water-based graphite lubricant in the thick wall region 20 and the transition region 19 of the tube blank 17 is simultaneously transformed into a dry film, and then extrusion and closing are performed, which is an effective method for forming aluminum-based composite tie rods. Secondly, the high-strength, high-modulus, fatigue-resistant tie rod processing solution provided by the present invention uses a composite ceramic mold 3 in the extrusion molding process. The mold material is a high-strength, high-hardness, high-smoothness, low-magnetic-permeability, and insulating material, which is very suitable for the electromagnetic heating extrusion molding of tie rods. In particular, the use of aramid fiber as the outer layer reinforcement structure ensures the passage of the electromagnetic field and the structural strength and durability of the mold. Third, the high-strength, high-modulus, fatigue-resistant tie rod processing solution provided by this invention has the advantages of high production efficiency, low energy consumption, low noise, and the ability to form low-plasticity materials compared with hot die cold part extrusion forming and cold die cold part rotary forging forming. It provides a feasibility for plastic processing of high-strength, high-modulus, fatigue-resistant metal composite materials, and can also optimize the traditional metal material tie rod forming method. Attached Figure Description

[0017] The accompanying drawings are provided to further understand the technical solutions of the present invention and constitute a part of the specification. They are used together with the embodiments of this application to explain the technical solutions of the present invention and do not constitute a limitation on the technical solutions of the present invention.

[0018] Figure 1 A schematic diagram of the structure of a ceramic mold in a processing device for a lightweight, high-strength, high-modulus, fatigue-resistant tie rod provided in an embodiment of the present invention; Figure 2 This is a schematic diagram of the overall structure of a processing device for a lightweight, high-strength, high-modulus, fatigue-resistant tie rod provided in an embodiment of the present invention; Figure 3This is a schematic diagram of the tube blank processed by the processing device for lightweight, high-strength, high-modulus, fatigue-resistant tie rods provided in this embodiment of the invention.

[0019] Explanation of reference numerals in the attached figures: 1. Top block; 2. Tie rod; 3. Ceramic mold; 4. Inductor coil; 5. Mounting flange; 6. Screw; 7. Rubber gasket; 8. Metal ring; 9. Core rod; 10. Alternating magnetic field; 11. Clamping block; 12. Large diameter tapering zone; 13. Equal diameter stabilizing zone; 14. Aramid fiber layer; 15. Small diameter tapering zone; 16. Annular mounting bayonet; 17. Tube blank; 18. Thin-walled zone; 19. Transition zone; 20. Thick-walled zone. Detailed Implementation

[0020] To make the objectives, technical solutions, and advantages of the present invention clearer, the embodiments of the present invention will be described in detail below with reference to the accompanying drawings. It should be noted that, unless otherwise specified, the embodiments and features described in this application can be arbitrarily combined with each other.

[0021] As explained in the background section, for structures with enclosed cavities, traditional machining methods cannot reach the inner surface of the part, and plastic processing is usually used. However, as the proportion of aluminum-based composite reinforcement increases, the material's mechanical properties become increasingly superior, but this is accompanied by a sharp decrease in thermal conductivity and plasticity, making it impossible to use traditional processes (cold forging or hot extrusion) to form hollow shuttle-shaped products like tie rods.

[0022] Aluminum-based composites are a type of structural material with a rich selection system and relatively mature technology. 15 vol.% SiC / 6xxx aluminum-based composites can achieve a tensile strength of up to 530 MPa, a yield strength of up to 435 MPa, a hardness of up to 170 HBS, a modulus of up to 105 GPa, and a thermal expansion of 18*10... -6 / K, density as low as 2.70 g / cm³ 3 The elongation at room temperature is as low as 4%. In contrast, conventional aluminum alloys such as 2A12 and T4 typically have a tensile strength of 450 MPa, a yield strength of 350 MPa, a hardness of 120 HBS, a modulus of 70 GPa, and a thermal expansion of 23.6 x 10⁻⁶. -6 / K, density is generally 2.80 g / cm³ 3 The elongation at room temperature in the annealed state can reach 10%.

[0023] In summary, 15 vol.%SiC / 6xxx aluminum-based composites exhibit superior mechanical properties compared to traditional 2A12 and T4 aluminum alloys, while maintaining a similar density. The inclusion of reinforcing phases simultaneously enhances its service fatigue performance, making it a promising candidate for structural tie rod applications. However, 15 vol.%SiC / 6xxx aluminum-based composites show significantly lower elongation compared to traditional 2A12 and T4 aluminum alloys, and their poor room-temperature plasticity makes cold-die forging an unsuitable method for forming aluminum-based composite tie rods. Utilizing a temperature field is recommended to improve its formability. However, the low thermal conductivity of SiC and the introduced interface effects hinder heat conduction, making it difficult for heat from the hot die to quickly transfer to the forming area of ​​the tie rod. Therefore, hot-die cold-part extrusion forming is also unsuitable. Consequently, it is necessary to develop a new forming method for obtaining aluminum-based composite tie rod parts.

[0024] Based on the above requirements, this invention provides a processing device and method for lightweight, high-strength, high-modulus, fatigue-resistant tie rods. The aim is to improve the plasticity of aluminum-based composite materials by electromagnetic induction heating of aluminum-based composite tube blanks, and to use a new type of mold material, composite ceramic mold, especially aramid fiber as the outer reinforcing structure, which not only meets the requirements for electromagnetic field passage, but also ensures the structural strength and durability of the mold.

[0025] The present invention provides the following specific embodiments, which can be combined with each other. For the same or similar concepts or processes, they may not be described again in some embodiments.

[0026] The design process of the processing device for lightweight, high-strength, high-modulus, fatigue-resistant tie rods provided in this embodiment of the invention is described below: To improve the plasticity of aluminum-based composites and enhance the flowability of the substrate and reinforcement, in-situ heating is applied to the formed tube blank. Commonly used local heating methods include thermal radiation, thermal conduction, self-resistance heating, and inductive heating. However, given the low thermal conductivity of aluminum-based composites, self-resistance heating and inductive heating are the preferred heating methods.

[0027] Self-resistance heating connects electrodes to both ends of the material and applies a voltage between them. The generated current relies on the material's own resistance to produce heat. Depending on the connection method of the electrodes, self-resistance heating can be divided into two modes: fixed electrode and sliding electrode. Fixed electrode self-resistance heating requires one electrode to be connected to the metal mold, and the other end to be fixedly connected to the end of the forming zone, heating the entire forming zone. To obtain the inner diameter of the forming rear end, the tie rod is in a non-uniform cross-sectional shape before forming, with a large cross-sectional area and low resistance at the front end of the forming zone, and a small cross-sectional area and high resistance at the rear end. According to Ohm's law, this results in a low temperature at the front end and a high temperature at the rear end of the forming zone, easily causing local material instability at the rear end of the forming zone during extrusion, which is detrimental to the extrusion process. Sliding electrode self-resistance heating requires one electrode to be connected to the metal mold, and the other end to contact the near end of the forming zone. This allows for precise control of the heating area, avoiding instability at the rear end of the forming zone. However, sliding electrodes are prone to electrical spark ablation of the material in the area swept by the sliding electrode, peeling off the surface lubricant, and fluctuations in heating power.

[0028] Inductive heating is a technology based on the principle of electromagnetic induction. It achieves heating by inducing eddy currents in a conductor through an alternating magnetic field. An alternating magnetic field is applied to the front end of the forming zone of the tube blank, raising its temperature. Simultaneously, the water-based graphite lubricant transforms into a dry film until the theoretical forming temperature (510℃~550℃) is reached. A feed pressure is then applied axially, forcing the front end of the forming zone into the mold. The forming zone is gradually heated by the alternating magnetic field and gradually extruded into the mold until all material from the forming zone enters the mold, achieving the final forming state.

[0029] If traditional die steel is used as the extrusion die, the die will absorb and block the alternating magnetic field from passing through the aluminum composite tube blank, preventing the temperature of the aluminum composite tube blank from increasing, and thus hindering the improvement of the plasticity of the aluminum composite tube blank. Therefore, this invention considers selecting a type of high-strength, high-hardness, high-gloss, low-permeability, and insulating material as the die material. Ceramic materials not only possess the above characteristics, but also, when used as extrusion dies, can achieve extremely high surface finish through grinding. The alternating magnetic field generated by the inductor coil outside the ceramic die can not only pass through the alumina die, but also induce a current in the forming zone of the aluminum composite tube blank, thereby heating the material at the front end of the forming zone to the theoretical forming temperature.

[0030] Due to the extremely high hardness and low plasticity of ceramic molds, it is practically impossible to prepare mounting holes. Furthermore, uneven installation stress can easily lead to brittle cracks. Therefore, after pressing the ceramic mold, two high-strength V-shaped metal semi-rings with positioning functions need to be installed inside the ceramic mold. During installation, the metal rings and mounting flanges are axially limited by multiple screws to prevent excessive axial displacement of the ceramic mold when the aluminum composite tie rod is removed. Because ceramics have excellent compressive strength but poor tensile strength, an aramid fiber layer is wound around the main stress area on the outside of the ceramic mold to give it higher structural strength and prevent cracking during extrusion.

[0031] Aluminum-based composite tie rod blanks of equal diameter are mostly thin-walled structures. During the end-capping process, sufficient material thickness cannot be achieved at the tie rod ends, often requiring pre-emptive material storage through plastic thickening. However, the interface between the reinforcing phase and the matrix in aluminum-based composites is prone to microscopic delamination during drastic thickening. Therefore, a preferred method is to use machining to store a certain amount of material on the exterior of the blank end for end-capping thickening. Specifically, by machining the outer wall of the thick-walled aluminum-based composite tube, the equal-diameter area of ​​the tie rod is thinned by turning, resulting in a dumbbell-shaped blank.

[0032] To accommodate the dumbbell shape of the tube blank entering the ceramic mold in the forming zone, this embodiment of the invention divides the ceramic mold into three continuous forming surfaces: a large-diameter narrowing zone, a stabilizing zone, and a small-diameter narrowing zone. The tube blank first enters the large-diameter narrowing zone. As the tube material is extruded into the large-diameter zone, the outer diameter of the tube blank in the forming zone gradually decreases, while the radial diameter increases, and the wall thickness increases. However, the wall thickness in the non-forming zone is relatively thin and lacks mold support, resulting in poor stability. Until the material in the forming zone has completely passed through the large-diameter narrowing zone, the tube blank in the non-forming zone enters the stabilizing zone. The inner diameter of the stabilizing zone is equal to the outer diameter of the tube blank in the non-forming zone. The tube blank in the non-forming zone is supported by the mold's stabilizing zone, which helps to stably provide the forming force for the material in the forming zone to enter the small-diameter narrowing zone.

[0033] The mounting flange is made of metal and is bolted to the machine tool. The flange provides limiting and axial support for the ceramic mold when subjected to axial pressure from the tube blank. A metal ring on the ceramic mold and a ring structure on the flange form radial positioning, and screws prevent the ceramic mold from being pulled out of the ring structure, thus avoiding excessive displacement of the ceramic mold due to tensile force during pull rod demolding. A threaded hole is located in the center of the flange, and the forming mandrel is installed in this hole. The forming mandrel provides a stable inward thickening constraint on the pull rod end.

[0034] Figure 1 A schematic diagram of the structure of a ceramic mold in a processing device for a lightweight, high-strength, high-modulus, fatigue-resistant tie rod provided in an embodiment of the present invention; Figure 2 This is a schematic diagram of the overall structure of a processing device for a lightweight, high-strength, high-modulus, fatigue-resistant tie rod provided in an embodiment of the present invention; Figure 3 A schematic diagram of the tube blank processed by the processing device for lightweight, high-strength, high-modulus, fatigue-resistant tie rods provided in this embodiment of the invention. (Refer to...) Figures 1 to 3 As shown, the processing device for lightweight, high-strength, high-modulus, fatigue-resistant tie rods provided in this embodiment of the invention may include: a top block 1, a clamping block 11, an inductor coil 4, and a mold assembly, wherein the main structure of the mold assembly is a ceramic mold 3.

[0035] like Figure 2 As shown, the tube blank 17 to be formed is clamped by the clamping block 11 installed on the side push plate of the machine tool so as to keep the tube blank 17 stably coaxial with the ceramic mold 3 during the processing; the top block 1 installed on the tailstock of the machine tool presses against the non-forming end of the tube blank 17.

[0036] In this embodiment of the invention, the inductor coil 4 is sleeved and installed outside the ceramic mold 3. The ceramic mold 3 is fixedly installed on the machine head of the equipment by the mounting flange 5. The screw 6 set in the central threaded hole of the mounting flange 5 is embedded and sleeved in the center of the mounting end of the ceramic mold 3. It is used as the forming structure of the forming end of the tube blank 17 through the space cavity formed by the inner surface of the ceramic mold 3 and the screw 6.

[0037] In this embodiment of the invention, the internal working cavity of the ceramic mold 3 is sequentially configured along the forming direction as a large-diameter closing area 12, an equal-diameter stabilizing area 13, and a small-diameter closing area 15; wherein, the inner diameter of the starting end of the large-diameter closing area 12 is larger than the outer diameter of the end of the tube blank 17.

[0038] Based on the structure of the forming device described above, the working method of the forming device is as follows: during the extrusion forming of one side of the tube blank 17, the alternating magnetic field 10 generated by the inductor coil 4 is used to induction heat the tube blank 17 in the large diameter narrowing area 12 of the ceramic mold 3. The thick wall area 20 of the tube blank 17 and the water-based graphite outside the transition area 19 first form a dry film. Through the continuous feeding of the ceramic mold 3, the thick wall area 20 and the transition area 19 of the tube blank 17 are continuously and sequentially extruded into the large diameter narrowing area 12, the equal diameter stabilizing area 13 and the small diameter narrowing area 15, thereby realizing the extrusion forming of one side of the tube blank 17.

[0039] In one implementation of this invention, such as Figure 2 As shown, the mold assembly includes: a ceramic mold 3, a mounting flange 5, screws 6, rubber gaskets 7, a metal ring 8, and a core rod 9.

[0040] In this implementation, the ceramic mold 3 is configured as a columnar structure with a hollow working cavity. An aramid fiber layer 14 is formed on the outside of the ceramic mold 3 by curing. The tail end of the ceramic mold 3 is fixedly installed to the mounting flange 5 by screws 6. A core rod 9 is installed in the central threaded hole of the mounting flange 5. An inductor coil 4 is sleeved on the outside of the aramid fiber layer 14 of the ceramic mold 3.

[0041] Furthermore, in this implementation method, such as Figure 2 As shown, the mold assembly also includes a rubber gasket 7. One end of the mounting flange 5 is provided with an annular boss, forming a mounting base for the ceramic mold 3. One end of the ceramic mold 3 is embedded in the mounting base formed by the annular boss, and a rubber gasket 7 is provided between the contact surfaces of the mounting flange 5 and the ceramic mold 3 to prevent the ceramic mold 3 from cracking under pressure. Furthermore, in this implementation method, such as Figure 2 As shown, the mold assembly also includes a metal ring 8. An annular mounting slot 16 is provided on the columnar outer wall of the ceramic mold 3 and the mounting flange 5. Two semi-circular metal rings 8 are installed in the annular mounting slot 16. The annular boss of the mounting flange 5 is radially pressed against the metal rings 8 of the annular mounting slot 16 of the ceramic mold 3 by multiple screws 6 to prevent the ceramic mold 3 from cracking under pressure.

[0042] It should be noted that the ceramic mold 3 in this embodiment of the invention is prepared as follows: ceramic material is formed into a ceramic mold 3 blank by slip casting. After the ceramic mold 3 blank is sintered, its working area and annular mounting slot 16 are polished so that the working area reaches a smoothness of not less than Ra0.1 and the annular mounting slot 16 reaches a smoothness of not less than Ra1.6. Then, an aramid fiber layer 14 is wrapped around the outside of the polished ceramic mold 3 blank and bonded and cured with the ceramic mold 3 blank to form the ceramic mold 3.

[0043] Based on the forming apparatus for lightweight, high-strength, high-modulus, fatigue-resistant tie rods provided in the above embodiments of the present invention, the present invention also provides a method for processing lightweight, high-strength, high-modulus, fatigue-resistant tie rods using the forming apparatus, comprising the following steps: Step 1: Prepare a tube blank 17 with a wall thickness in the middle that is smaller than that at both ends. Roughen the ends of the tube blank 17 and make the inner hole in the middle of the tube blank 17 of equal diameter. Step 2: Install the tube blank 17 and adjust the position of the ceramic mold 3 and the tube blank 17 using the equipment to extrude and form one side of the tube blank 17. Step 3: Demold the tube blank 17 that has been extruded on one side. Step 4: Repeat steps 1 to 3 to process the other end of the tube blank 17.

[0044] This invention provides a processing apparatus and method for lightweight, high-strength, high-modulus, fatigue-resistant tie rods. During the extrusion forming of one side of the tube blank 17, an alternating magnetic field 10 generated by an inductor coil 4 induction heats the tube blank 17 within the large-diameter tapering region 12 of the ceramic mold 3. A dry film first forms between the thick-walled region 20 of the tube blank 17 and the water-based graphite outside the transition region 19. Through continuous feeding from the ceramic mold 3, the thick-walled region 20 and the transition region 19 of the tube blank 17 are continuously and sequentially extruded into the large-diameter tapering region 12, the constant-diameter stabilization region 13, and the small-diameter tapering region 15, thus achieving extrusion forming of one side of the tube blank 17. The processing technology solution for lightweight, high-strength, high-modulus, fatigue-resistant tie rods provided by this invention has the following beneficial effects: First, the high-strength, high-modulus, fatigue-resistant tie rod processing solution provided by the present invention improves the plasticity of aluminum-based composite tube blank by electromagnetic induction heating. During the heating process, the water-based graphite lubricant in the thick wall region 20 and the transition region 19 of the tube blank 17 is simultaneously transformed into a dry film, and then extrusion and closing are performed, which is an effective method for forming aluminum-based composite tie rods. Secondly, the high-strength, high-modulus, fatigue-resistant tie rod processing solution provided by the present invention uses a composite ceramic mold 3 in the extrusion molding process. The mold material is a high-strength, high-hardness, high-smoothness, low-magnetic-permeability, and insulating material, which is very suitable for the electromagnetic heating extrusion molding of tie rods. In particular, the use of aramid fiber as the outer layer reinforcement structure ensures the passage of the electromagnetic field and the structural strength and durability of the mold. Third, the high-strength, high-modulus, fatigue-resistant tie rod processing solution provided by this invention has the advantages of high production efficiency, low energy consumption, low noise, and the ability to form low-plasticity materials compared with hot die cold part extrusion forming and cold die cold part rotary forging forming. It provides a feasibility for plastic processing of high-strength, high-modulus, fatigue-resistant metal composite materials, and can also optimize the traditional metal material tie rod forming method.

[0045] The following is an illustrative description of the implementation of the processing apparatus and method for lightweight, high-strength, high-modulus, fatigue-resistant tie rods provided in the embodiments of the present invention.

[0046] Implementation Example The components of the processing device for the lightweight, high-strength, high-modulus, fatigue-resistant tie rod provided in this embodiment include: a top block 1, a ceramic mold 3, an inductor coil 4, a mounting flange 5, screws 6, rubber gaskets 7, a metal ring 8, a core rod 9, and a clamping block 11.

[0047] like Figure 1The structure of the ceramic mold 3 shown is as follows. The ceramic mold 3 is made of a new type of ceramic material, such as a mixture of alumina, silicon nitride powder and paraffin wax, which is formed by slip casting process to form the ceramic mold 3 blank. After the ceramic mold 3 blank is sintered, the working area and installation position, namely the large diameter tapering area 12, the equal diameter stabilizing area 13, the small diameter tapering area 15, and the annular mounting bayonet 16, are polished so that the large diameter tapering area 12, the equal diameter stabilizing area 13, and the small diameter tapering area 15 achieve a surface finish of not less than Ra0.1, and the annular mounting bayonet 16 achieves a surface finish of not less than Ra1.6. An aramid fiber layer 14 is wrapped around the outside and bonded and cured with the ceramic mold 3.

[0048] The implementation example provides an installation structure for the machining device of a lightweight, high-strength, high-modulus, fatigue-resistant tie rod, such as... Figure 2 As shown. The installation process of the processing device is as follows: The mounting flange 5 is installed on the machine head using screws 6. The core rod 9 is screwed into the threaded hole in the center of the mounting flange 5. A high-temperature resistant rubber gasket 7 is placed at the bottom of the annular boss of the mounting flange 5. Two semi-circular metal rings 8 are installed in the annular mounting bayonet 16 of the ceramic mold 3. The ceramic mold 3 and the two semi-circular metal rings 8 are placed together into the annular boss of the mounting flange 5. Multiple screws 6 are used to pass through the annular boss of the mounting flange 5 to tighten the ceramic mold 3 in the radial direction. An inductor coil 4 is fitted onto the outside of the ceramic mold 3. At this time, the relative positions of the ceramic mold 3, inductor coil 4, mounting flange 5, screws 6, rubber gasket 7, metal rings 8, and core rod 9 are fixed. The top block 1 and clamping block 11 are respectively installed on the machine tool tailstock and side push plate.

[0049] This implementation example provides a method for manufacturing a lightweight, high-strength, high-modulus, fatigue-resistant tie rod, including the following steps: Step 1: Prepare tube blank 17; like Figure 3 As shown, the outer wall of the thick-walled aluminum composite tube is machined to obtain a tube blank 17 with a dumbbell shape. Thread structures with a depth of 0.2 mm and a spacing of 1 mm are machined in the thick-walled area and transition area at both ends of the tube blank 17, and then coated with water-based graphite lubricant.

[0050] Step 2: Forming and installing one end of tube blank 17 like Figure 2 As shown, the machine head drives the ceramic mold 3 back to the initial position, the two semi-circular clamping blocks 11 open, the top block 1 moves away from the clamping blocks 11, and the tube blank 17 is placed in the two semi-circular clamping blocks 11. The two semi-circular clamping blocks 11 close and apply clamping force. The top block 1 moves from the initial position along the axial direction and contacts the end face of the non-forming end of the tube blank 17 and then applies a counter-pushing force to adjust the position of the ceramic mold 3 on the machine head so that the ceramic mold 3 coincides with the central axis of the tube blank 17.

[0051] Step 3: Extrusion forming process of one side end of tube blank 17 like Figure 2 As shown, the inductor coil 4 is activated, generating an alternating magnetic field 10. The inner diameter of the starting end of the large-diameter tapering zone 12 is slightly larger than the outer diameter of the tube blank 17. The die head drives the ceramic mold 3 to slowly move towards the tube blank 17 until the tube blank 17 enters the large-diameter tapering zone 12. The tube blank 17 is induced heated by the alternating magnetic field 10. The water-based graphite outside the thick-walled zone 20 and the transition zone 19 first forms a dry film. After a preset time, the temperature of the thick-walled zone 20 of the tube blank 17 can reach 510-550℃. Depending on the different sizes of the thick-walled zone 20 of the different pull rods, the ceramic mold 3 is fed forward at a slow speed of 0.5-2mm / s. The thick-walled zone 20 and the transition zone 19 are continuously and sequentially squeezed into the large-diameter tapering zone 12, the equal-diameter stabilization zone 13, and the small-diameter tapering zone 15. When the thin-walled zone 18 of the tube blank 17 enters the equal-diameter stabilization zone 13, the inductor coil 4 is stopped to prevent the thin-walled zone 18 from overheating and becoming unstable. When the ceramic mold 3 is fed to the theoretical position, the tube blank 17 completes the extrusion forming process.

[0052] Step 4: Demolding the first end of tube blank 17. like Figure 2 As shown, the top block 1 retracts to the initial position, the machine head carrying the ceramic mold 3 retracts to the initial position, the two semi-circular clamping blocks 11 open, and the pull rod 2, which has completed the single-sided end extrusion forming, is taken out.

[0053] Step 5: Forming and installing the other end of tube blank 17 like Figure 2 As shown, the die head drives the ceramic mold 3 back to the initial position, the two semi-circular clamping blocks 11 open, the top block 1 moves away from the clamping blocks 11, and the tube blank 17 is placed in the two semi-circular clamping blocks 11. The two semi-circular clamping blocks 11 close and apply clamping force. The top block 1 moves from the initial position along the axial direction and contacts the end face of the tube blank 17 after the end has been closed, and then applies a counter-pushing force to adjust the position of the ceramic mold 3 on the die head so that the ceramic mold 3 coincides with the central axis of the tube blank 17.

[0054] Step six, extrusion forming process on the other end of tube blank 17 like Figure 2As shown, the inductor coil 4 is activated, generating an alternating magnetic field 10. The inner diameter of the starting end of the large-diameter tapering zone 12 is slightly larger than the outer diameter of the tube blank 17. The die head drives the ceramic mold 3 to slowly move towards the tube blank 17 until the tube blank 17 enters the large-diameter tapering zone 12. The tube blank 17 is induced heated by the alternating magnetic field 10. The water-based graphite outside the thick-walled zone 20 and the transition zone 19 first forms a dry film. After a preset time, the temperature of the thick-walled zone 20 of the tube blank 17 can reach 510-550℃. Depending on the different sizes of the thick-walled zone 20 of the different pull rods, the ceramic mold 3 is fed forward at a slow speed of 0.5-2mm / s. The thick-walled zone 20 and the transition zone 19 are continuously and sequentially squeezed into the large-diameter tapering zone 12, the equal-diameter stabilization zone 13, and the small-diameter tapering zone 15. When the thin-walled zone 18 of the tube blank 17 enters the equal-diameter stabilization zone 13, the inductor coil 4 is stopped to prevent the thin-walled zone 18 from overheating and becoming unstable. When the ceramic mold 3 is fed to the theoretical position, the tube blank 17 completes the extrusion forming process.

[0055] Step 7: Demolding the end of tube blank 17. like Figure 2 As shown, the top block 1 retracts to the initial position, the machine head carrying the ceramic mold 3 retracts to the initial position, the two semi-circular clamping blocks 11 open, and the pull rod 2, which has been extruded and formed on both sides, is taken out.

[0056] The processing scheme for lightweight, high-strength, high-modulus, fatigue-resistant tie rods provided in this invention belongs to the research results of high-quality and high-efficiency non-isothermal hot extrusion forming technology for high-strength aluminum alloy tie rods. The plasticity of the aluminum-based composite material is improved by electromagnetic induction heating of the aluminum-based composite tube blank. The composite ceramic mold used in the forming process is made of a high-strength, high-hardness, high-smoothness, low-magnetic-permeability, and insulating material, which is highly suitable for electromagnetic heating extrusion forming of tie rods. In particular, the use of aramid fiber as the outer reinforcing structure satisfies the requirements for electromagnetic field passage while ensuring the structural strength and durability of the mold.

[0057] While the embodiments disclosed in this invention are as described above, they are merely illustrative of the embodiments to facilitate understanding of the invention and are not intended to limit the invention. Any person skilled in the art to which this invention pertains may make any modifications and variations in the form and details of the implementation without departing from the spirit and scope disclosed herein; however, the scope of patent protection for this invention shall still be determined by the scope defined in the appended claims.

Claims

1. A processing device for lightweight, high-strength, high-modulus, fatigue-resistant tie rods, characterized in that, include: The top block (1), clamping block (11), inductor coil (4) and mold assembly, wherein the main structure of the mold assembly is a ceramic mold (3). The tube blank (17) to be formed is clamped by a clamping block (11) installed on the side push plate of the machine tool so as to keep the tube blank (17) in a stable coaxial position with the ceramic mold (3) during the processing; the top block (1) installed on the tailstock of the machine tool presses against the non-forming end of the tube blank (17); The inductor coil (4) is sleeved and installed outside the ceramic mold (3). The ceramic mold (3) is fixedly installed on the machine head of the equipment by the mounting flange (5). The screw (6) set in the central threaded hole of the mounting flange (5) is embedded in the center of the mounting end of the ceramic mold (3) and used as the forming structure of the forming end of the tube blank (17) through the space cavity formed by the inner surface of the ceramic mold (3) and the screw (6). The internal working cavity of the ceramic mold (3) is sequentially configured along the forming direction as a large-diameter closing area (12), an equal-diameter stabilizing area (13), and a small-diameter closing area (15); wherein, the inner diameter of the starting end of the large-diameter closing area (12) is larger than the outer diameter of the end of the tube blank (17); The forming device is used to generate an alternating magnetic field (10) through an inductor coil (4) to induction heat the tube blank (17) in the large diameter narrowing area (12) of the ceramic mold (3) during the extrusion forming of one side of the tube blank (17). The water-based graphite outside the thick wall area (20) and the transition area (19) of the tube blank (17) first forms a dry film. Through the continuous feeding of the ceramic mold (3), the thick wall area (20) and the transition area (19) of the tube blank (17) are continuously and sequentially extruded into the large diameter narrowing area (12), the equal diameter stabilizing area (13) and the small diameter narrowing area (15), thereby realizing the extrusion forming of one side of the tube blank (17).

2. The forming device for a lightweight, high-strength, high-modulus, fatigue-resistant tie rod according to claim 1, characterized in that, The mold assembly includes: a ceramic mold (3), a mounting flange (5), screws (6), a rubber gasket (7), a metal ring (8), and a core rod (9); The ceramic mold (3) is configured as a columnar structure with a hollow working cavity. An aramid fiber layer (14) is formed on the outside of the ceramic mold (3) by curing. The tail end of the ceramic mold (3) is fixedly installed to the mounting flange (5) by screws (6). A core rod (9) is installed in the central threaded hole of the mounting flange (5). An inductor coil (4) is sleeved on the outside of the aramid fiber layer (14) of the ceramic mold (3).

3. The forming device for a lightweight, high-strength, high-modulus, fatigue-resistant tie rod according to claim 2, characterized in that, The mold assembly also includes: a rubber pad (7); One end of the mounting flange (5) is provided with an annular boss to form a mounting seat for the ceramic mold (3). One end of the ceramic mold (3) is embedded in the mounting seat formed by the annular boss, and a rubber pad (7) is provided between the contact end face of the mounting flange (5) and the ceramic mold (3) to prevent the ceramic mold (3) from being squeezed and cracked.

4. The forming device for a lightweight, high-strength, high-modulus, fatigue-resistant tie rod according to claim 2, characterized in that, The mold assembly also includes: a metal ring (8); The cylindrical outer wall of the ceramic mold (3) and the mounting flange (5) is provided with an annular mounting slot (16). Two semi-circular metal rings (8) are installed in the annular mounting slot (16). The annular boss of the mounting flange (5) is pressed radially onto the metal rings (8) of the annular mounting slot (16) of the ceramic mold (3) by multiple screws (6) to prevent the ceramic mold (3) from being squeezed and cracked.

5. A forming device for a lightweight, high-strength, high-modulus, fatigue-resistant tie rod according to any one of claims 1 to 4, characterized in that, The ceramic mold (3) is prepared by: ceramic material is formed into ceramic mold (3) blank by slurry injection; after the ceramic mold (3) blank is sintered, its working area and annular mounting slot (16) are polished so that the working area reaches a smoothness of not less than Ra0.1 and the annular mounting slot (16) reaches a smoothness of not less than Ra1.6; and aramid fiber layer (14) is wrapped around the outside of the polished ceramic mold (3) blank and bonded and cured with the ceramic mold (3) blank to form ceramic mold (3).

6. A method for processing a lightweight, high-strength, high-modulus, fatigue-resistant tie rod, characterized in that, A method for processing a lightweight, high-strength, high-modulus, fatigue-resistant tie rod using the forming apparatus described in any one of claims 1 to 5 includes: Step 1: Prepare a tube blank (17) with a wall thickness in the middle that is smaller than that at both ends. Roughen both ends of the tube blank (17) and make the inner hole in the middle of the tube blank (17) equal in diameter. Step 2: Install the tube blank (17) and adjust the position of the ceramic mold (3) and the tube blank (17) using the equipment to extrude and form one side of the tube blank (17); Step 3: Demold the tube blank (17) that has been extruded on one side. Step 4: Repeat steps 1 to 3 to process the other end of the tube blank (17).

7. The processing method for a lightweight, high-strength, high-modulus, fatigue-resistant tie rod according to claim 6, characterized in that, Step 1 includes: The outer wall of the thick-walled aluminum composite tube is machined to form a dumbbell-shaped tube blank (17) with a wall thickness of less than that of the thick-walled areas (20) at both ends. The thick-walled areas (20) and transition areas (19) at both ends of the tube blank (17) are roughened by turning. Water-based graphite lubricant is applied to the roughened areas.

8. The processing method for a lightweight, high-strength, high-modulus, fatigue-resistant tie rod according to claim 7, characterized in that, Step 2 includes: Step 21: Place the equipment in the initial state, clamp the tube blank (17) with the clamping block (11), and after the top block (1) moves from the initial position along the axial direction to the end face of the non-forming end of the tube blank (17), apply a counter-thrust force, adjust the position of the ceramic mold (3) on the machine head of the equipment so that the ceramic mold (3) coincides with the central axis of the tube blank (17); Step 22: Start the inductor coil (4) to generate an alternating magnetic field (10). The die head drives the ceramic mold (3) to move slowly toward the tube blank (17) until the forming end of the tube blank (17) enters the large diameter narrowing zone (12). The tube blank (17) is heated by the alternating magnetic field (10). The water-based graphite outside the thick wall area (20) and the transition zone (19) of the tube blank (17) first forms a dry film. The ceramic mold (3) continues to feed the tube blank (17), so that the thick wall area (20) and the transition zone (19) of the tube blank (17) are continuously and sequentially squeezed into the large diameter narrowing zone (12), the equal diameter stabilization zone (13) and the small diameter narrowing zone (15). When the thin wall area (18) of the tube blank (17) enters the equal diameter stabilization zone (13), the inductor coil (4) stops being energized. When the ceramic mold (3) is fed to the theoretical position, the tube blank (17) completes the extrusion forming process.

9. The processing method for a lightweight, high-strength, high-modulus, fatigue-resistant tie rod according to claim 8, characterized in that, Step 3 includes: The top block (1) retracts to the initial position, the machine head carrying the ceramic mold (3) retracts to the initial position, the two semi-circular clamping blocks (11) open, and the pull rod (2) that has completed the single-sided end extrusion forming is taken out.

10. The processing method of a lightweight, high-strength, high-modulus fatigue-resistant tie rod according to claim 9, characterized in that, Step 4 includes: Step 41, forming and installing the other end of the tube blank (17), includes: placing the equipment in the initial state, clamping the tube blank (17) with the clamping block (11), moving the top block (1) from the initial position along the axial direction to the end face of the tube blank (17) after contacting the closed end, applying a counter-thrust force, adjusting the position of the ceramic mold (3) on the equipment head so that the ceramic mold (3) coincides with the central axis of the tube blank (17); Step 42: Start the inductor coil (4) to generate an alternating magnetic field (10). The die head drives the ceramic mold (3) to move slowly toward the tube blank (17) until the forming end of the tube blank (17) enters the large diameter narrowing zone (12). The tube blank (17) is heated by the alternating magnetic field (10). The water-based graphite on the outside of the thick wall area (20) and the transition zone (19) of the tube blank (17) first forms a dry film. The ceramic mold (3) continues to feed toward the tube blank (17). The thick wall area (20) and the transition zone (19) of the tube blank (17) are continuously and sequentially squeezed into the large diameter narrowing zone (12), the equal diameter stabilization zone (13), and the small diameter narrowing zone (15). When the thin wall area (18) of the tube blank (17) enters the equal diameter stabilization zone (13), the inductor coil (4) stops being energized. When the ceramic mold (3) is fed to the theoretical position, the tube blank (17) completes the extrusion forming process. Step 43: The top block (1) returns to the initial position, the machine head carrying the ceramic mold (3) returns to the initial position, the two semi-circular clamping blocks (11) open, and the pull rod (2) that has been extruded and formed on both sides is taken out.

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