Telescopic member lightweight structure and composite manufacturing method

Abstract

The invention belongs to the field of material processing and manufacturing, and relates to structural design and manufacturing of telescopic components. The single sleeve side wall topological sandwich structure is adopted to form a thin-wall panel + micro truss + thin-wall panel structure, the rigidity of the component can be effectively improved, the weight of the component is reduced to the maximum extent, and the requirements for the bearing capacity and light weight of the component are met; by adopting the process of forming the final single component through the laser deposition connection prefabricated part after the selective laser forming prefabricated part is adopted, the limitation of forming equipment on the size can be broken through, the consistency of the overall structure performance of the component can be guaranteed to the maximum extent, and high-quality manufacturing of the large-size component is achieved.

Description

Technical Field

[0001] The invention belongs to the field of material processing and manufacturing, and relates to a lightweight structure of a telescopic component and a composite manufacturing method. Background Art

[0002] High load-bearing capacity and high mobility have become the development direction of new vehicles, and the contradiction between lightweight design of its load-bearing structure and high load-bearing efficiency is becoming increasingly prominent. Lightweight is the key to the structural design of new vehicles. Retractable components are widely used in mobile vehicles. They are favored by engineers for their lightness, high strength and flexible structure. At present, the commonly used retractable components are basically formed by mechanical processing and cutting. The side walls of the components formed by this method are generally solid structures. The solid structure has the problem of contradiction between rigidity and lightweight requirements. If the rigidity is pursued, the wall thickness needs to be thickened, and the weight will also increase. If the lightweight demand is pursued, the rigidity will be reduced while the mass is reduced. In recent years, with the application of lightweight topological structures becoming more and more mature, its advantages of less consumables and good structural stability have gradually emerged. A large number of application verifications have been carried out in the engineering field, and good results have been achieved. Topological optimization is the main design method in the conceptual design stage of the structure. Its basic idea is to transform the problem of seeking the optimal topology of the structure into the problem of solving the optimal layout of the materials in the design area, so as to achieve the optimization goal. As a high-quality manufacturing method of new concept structures, additive manufacturing technology improves the designability of component structures, has considerable adaptability to the manufacturing of topological structures, is widely used in the engineering community, and provides a new technical path for the manufacturing of complex components. However, additive manufacturing needs to be carried out in a box, which limits the size of the component that can be formed at one time. Therefore, after the component is formed, it needs mechanical connection to achieve the technical indicators of the final component. However, mechanical connection increases the mass of the component, which does not conform to the development concept of lightweight. At the same time, the optimization paths and methods are different for different component structures and applications. Therefore, the optimization methods and final structural forms of telescopic components are of great significance. The manufacturing methods used for the optimized structure also need further demonstration and application verification. Summary of the invention

[0003] In accordance with the above-mentioned problem of the contradiction between the bearing capacity of components and the lightweight demand, the present invention takes telescopic components as the object and provides a telescopic component lightweight structure and composite manufacturing method. The present invention mainly adopts lightweight design ideas to optimize the structure of telescopic components on the design side, and mainly uses the two-step manufacturing technology of preforming and then connecting on the manufacturing side, breaking the bottleneck that large components are difficult to form due to size restrictions, and uses laser selective melting forming technology to carry out the manufacture of prefabricated components. After that, the prefabricated components are connected by laser deposition forming method, and finally the assembly and forming of the final component product is completed. The design and manufacturing technology involved in the present invention can effectively reduce the weight of the component while ensuring the stiffness of the component, breaking through the contradiction between the bearing capacity of the component and the lightweight demand, liberating the design idea, and using the laser deposition forming method to connect the laser selective melting prefabricated parts, which can effectively ensure the consistency of the final component structure and performance.

[0004] The technical means adopted by the present invention are as follows:

[0005] The telescopic member has a lightweight structure, and the overall structure is a multi-section sleeve-type thin-walled structure. During the sleeve assembly and forming process, it is positioned by the limit block on the inner side of the side wall. The side wall of the single sleeve member adopts topological optimization to form a sandwich configuration, and the secondary load-bearing area of ​​the side wall adopts a hollow topological structure to achieve the purpose of overall weight reduction of the member and realize the coordination of the lightweight demand and bearing capacity of the member. In the manufacturing process, for large single sleeve structures that exceed the forming capacity of the equipment, the laser selective melting forming process is used to first manufacture the prefabricated components, and then the laser deposition forming process is used to connect the prefabricated components to achieve the final forming of the component.

[0006] The segmented sleeve type thin-walled structure refers to several hollow rectangular or square thin-walled components with unequal side lengths, which are combined into a set structure in the order of decreasing side lengths from the outside to the inside, and except for the smallest size sleeve, the remaining sleeves are installed with limit blocks on the inner side of the eight top corners of the component, and the limit blocks are connected to the sleeve wall by bolts. At the same time, except for the largest sleeve, the remaining sleeves are integrally formed with step structures outside the top four top corners, which are used to cooperate with the limit blocks to control the extension of the sleeve;

[0007] The size of the single sleeve component should be such that, in addition to ensuring a close fit within a range of not less than 50 mm above and below the sleeve, a gap of at least 0.2 mm on one side is set in the middle section to ensure that there is no jamming or interference during the expansion and contraction and retraction process within the middle section;

[0008] The topological sandwich configuration of the side wall of the monomer sleeve component is a "thin-wall panel + micro-truss + thin-wall panel" structure, and the middle layer lattice is preferably a body-centered cubic unit cell structure (regular hexagonal cross section);

[0009] The hollow topological structure of the secondary load-bearing area is a triangular configuration filled with a mesh grille. The three corners of the triangle need to be rounded to improve the stress concentration caused by the sharp angles. The strong stability of the triangle can be fully utilized to improve the rigidity of the component. The mesh grille filled inside can effectively improve the stress behavior of the triangular hollow part and enhance the bearing capacity of the overall component.

[0010] The composite manufacturing method of the lightweight structure of the telescopic member comprises the following steps:

[0011] Step 1: Prefabricated component processing

[0012] The prefabricated components are based on the size of the production equipment. Components that exceed the forming capacity of the laser selective forming equipment need to be formed in sections first. Therefore, the process separation surface should be selected in the middle of the component to leave a clamping space for the subsequent connection process, and the side walls on both sides of the process separation surface are replaced with a solid structure to replace the topological sandwich structure. In order to avoid destroying the integrity of the sleeve structure, the process separation surface should be preferably in the middle of the component and should also avoid the triangular hollow feature.

[0013] Step 2: Prefabricated components are formed by laser selective melting

[0014] The laser selective melting forming process of the prefabricated component requires a 0.5mm removal margin to be reserved on the surface of the subsequent matching area, and based on its most prominent features of large-area hollow thin walls and micro-truss filling, it should be perpendicular to the substrate during forming to improve the forming accuracy of the main features, reduce the support weight, and increase the printing speed;

[0015] Step 3: Laser deposition forming to connect prefabricated components

[0016] The laser deposition forming and connecting prefabricated components is to control the deformation of the component connection process by designing the groove specifications and optimizing the connection sequence of the prefabricated components completed by the laser selective melting process, and finally complete the connection of the prefabricated components;

[0017] Step 4: All internal and external surfaces are machined to remove machining allowances to complete the manufacture of the prefabricated body, and then assembled to finally complete the manufacture of the telescopic member.

[0018] The connection groove is designed as a V-shaped groove or an X-shaped groove, with a groove angle of 60°, and a 1mm blunt edge should be left at the bottom of the groove. When the wall back is less than 10mm, a V-shaped groove is opened, and when the wall back is greater than 10mm, an X-shaped groove is opened, so as to suppress the root from being unfused during connection and improve thermal deformation;

[0019] The connection sequence is to connect opposite sides, fill multiple layers and multiple channels layer by layer, and complete the final connection.

[0020] Beneficial effects of the present invention:

[0021] (1) The single-sleeve side wall topology sandwich structure is a "thin-wall panel + micro-truss + thin-wall panel" structure, which can effectively improve the rigidity of the component, minimize the weight of the component, and meet the requirements of component bearing capacity and lightweight;

[0022] (2) The process of laser selective forming of preforms followed by laser deposition forming to connect the preforms to form the final single component can break through the size limitations of the forming equipment and ensure the consistency of the overall organizational performance of the component to the greatest extent, thus achieving high-quality manufacturing of large-size components. BRIEF DESCRIPTION OF THE DRAWINGS

[0023] Figure 1 It is a schematic diagram of a telescopic lightweight component;

[0024] Figure 2 It is a schematic diagram of typical parts of the sleeve;

[0025] Figure 3 It is a schematic diagram of the prefabricated body separation surface;

[0026] Figure 4 Schematic diagram of the laser selective forming placement of the preform;

[0027] Figure 5 Schematic diagram of the connection groove of the prefabricated body;

[0028] Figure 6 Schematic diagram of the connection sequence.

[0029] In the figure: 1 is sleeve A; 2 is sleeve B; 3 is sleeve C; 4 is a triangular hollow structure; 5 is a limit block; 6 is a step structure; 7 is a matching surface; 8 is a gradient transition area; 9 is a prefabricated body separation surface; 10 is an inner wall; 11 is an outer wall; 12 is a body-centered cubic unit cell topological micro-truss structure; 13 is a base plate; 14 is a prefabricated body frame; 15 is a prefabricated body frame; 16 is a groove; 17 is a blunt edge. DETAILED DESCRIPTION

[0030] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. Obviously, the drawings in the following description are embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative labor.

[0031] The telescopic lightweight component is mainly composed of three sleeves, namely, sleeve A1, sleeve B2 and sleeve C3, wherein the side wall of the sleeve is provided with a triangular hollow structure 4 with a built-in topological structure and sharp rounded corners, and the top and bottom of a single sleeve are equipped with eight corners fixed by bolt connection. Except for the smallest-sized sleeve C3, the other sleeves are all equipped with limited blocks 5 on the inner side of the eight corners of the component by bolt connection. At the same time, except for the largest-sized sleeve A1, the other sleeves are integrally formed with a step structure 6 outside the top four corners, and a gradient transition zone 8 with a width dimension greater than the size of the mating surface 7 by 0.2 mm is formed on the inner wall of the sleeve cavity. The preform dividing surface 9 is selected in the middle of the sleeve component. The sleeve wall is composed of an inner wall 10, an outer wall 11 and a body-centered cubic unit cell topological micro-truss structure 12 therebetween to form a lightweight structure. The 100 mm range of the dividing surface 9 is a solid structure for the manufacturing of the groove during subsequent connection.

[0032] When the preform of the telescopic lightweight component is formed by laser selective melting, it is necessary to use the forming substrate 13 as a basis, and the preform frames 14 and 15 should be perpendicular to the substrate surface;

[0033] The preform laser selective melting forming process of AlSi10Mg material is as follows: laser power 450W, scanning speed 1600mm / s, overlap width 0.15mm;

[0034] The finished preform is cut with the dividing surface 9 as the reference to form the groove 16 required for connection. The groove angle is 60°, and the bottom of the groove is formed with a blunt edge 17 with a height of 1 mm. The connection forming is divided into a bottom connection and a filling connection. The order of each process is as follows: Figure 6 As shown in ①→②→③→④→①→…, until the spaces of the straight grooves on all sides are fully filled, a blank component of the sleeve is formed. The laser deposition forming connection process is a laser power of 3000-3500W, a scanning speed of 10-15mm / s, a powder feeding speed of 5-15g / min, and a laser defocusing amount of 15mm;

[0035] Finally, the sleeve blank component is machined to remove process allowances, and the manufacturing of the sleeve component is finally completed.

Claims

1. Lightweight structure of telescopic components, It is characterized in that The overall structure is a multi-section sleeve-type thin-walled structure. During the sleeve assembly and forming process, the sleeve is positioned by a limit block on the inner side of the side wall. The side wall of the single sleeve component adopts topological optimization to form a sandwich configuration, and the secondary load-bearing area of ​​the side wall adopts a hollow topological structure. The segmented sleeve type thin-walled structure is composed of several hollow rectangular or square thin-walled components with unequal side lengths, which are combined into a set structure in the order of decreasing side lengths from the outside to the inside. Except for the smallest size sleeve, the remaining sleeves are equipped with limit blocks on the inner sides of the eight top corners of the component, and the limit blocks are connected to the sleeve wall by bolts. At the same time, except for the largest sleeve size sleeve, the remaining sleeves are integrally formed with a step structure outside the top four top corners, which is used to cooperate with the limit blocks to control the extension amount of the sleeve.

2. The telescopic member lightweight structure according to claim 1, It is characterized in that The size of the single sleeve component is such that, in addition to a tight fit within a range of not less than 50 mm at the upper and lower ends of the sleeve, a gap of at least 0.2 mm on one side is set in the middle section.

3. The telescopic member lightweight structure according to claim 1 or 2, It is characterized in that The topological sandwich configuration of the side wall of the monomer sleeve component is a "thin-wall panel + micro-truss + thin-wall panel" structure, and the middle layer lattice is a body-centered cubic unit cell structure.

4. The telescopic member lightweight structure according to claim 1 or 2, It is characterized in that The hollow topological structure of the secondary load-bearing area is a triangular configuration filled with a mesh grid, and the three corners of the triangle need to be rounded.

5. The telescopic member lightweight structure according to claim 3, It is characterized in that The hollow topological structure of the secondary load-bearing area is a triangular configuration filled with a mesh grid, and the three corners of the triangle need to be rounded.

6. A composite manufacturing method for a lightweight structure of a telescopic member according to any one of claims 1 to 5, It is characterized in that Here are the steps: Step 1: Prefabricated component processing The prefabricated components are based on the size of the production equipment. The components that exceed the forming capacity of the laser selective forming equipment need to be formed in sections first. The process separation surface should be selected in the middle of the component, and the side walls on both sides of the process separation surface are replaced with solid structures to replace the topological sandwich structure, avoiding triangular hollow features. Step 2: Prefabricated components are formed by laser selective melting The laser selective melting forming process of the prefabricated component requires a 0.5mm removal margin to be reserved on the surface of the subsequent matching area, and based on its most prominent features of large-area hollow thin walls and micro-truss filling, it should be perpendicular to the substrate during forming; Step 3: Laser deposition forming to connect prefabricated components The laser deposition forming and connecting prefabricated components is to control the deformation of the component connection process by designing the groove specifications and optimizing the connection sequence of the prefabricated components completed by the laser selective melting process, and finally complete the connection of the prefabricated components; Step 4: All internal and external surfaces are machined to remove machining allowances to complete the manufacture of the prefabricated body, and then assembled to finally complete the manufacture of the telescopic member.

7. The composite manufacturing method of the lightweight structure of the telescopic member according to claim 6, It is characterized in that In the third step, the connecting groove is designed as a V-shaped groove or an X-shaped groove, the groove angle is 60°, and a 1mm blunt edge should be left at the bottom of the groove. When the wall back is less than 10mm, a V-shaped groove is opened, and when the wall back is greater than 10mm, an X-shaped groove is opened.

8. The composite manufacturing method of the lightweight structure of the telescopic member according to claim 6, It is characterized in that In the third step, the connection sequence is to connect opposite sides, fill multiple layers and multiple channels layer by layer, and complete the final connection.

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