Manufacturing method of self-tapping and self-locking threads for light materials

Abstract

The invention relates to the technical field of fastener thread design, and discloses a manufacturing method of a self-tapping and self-locking thread for a light material, which comprises the following steps of: 1, selecting a proper metal material as a raw material of the self-tapping and self-locking thread according to the type of the light material, and ensuring that the hardness and toughness of the self-tapping and self-locking thread meet requirements; step 2, processing the materials selected in the step 1 into blanks with required sizes and shapes; and 3, an initial graph is constructed on the section, where threads need to be manufactured, of the blank, an initial image is obtained through geometric segmentation and rotation and translation operation, and the self-tapping and self-locking threads are formed on the blank after structural optimization. According to the manufacturing method of the self-tapping and self-locking thread for the light material, the proper metal material is selected according to the type of the light material, it is guaranteed that the hardness and toughness of the raw material are matched with those of the light material, and when the self-tapping and self-locking thread is connected with aluminum alloy, the selected metal material can guarantee that the manufactured thread is smoothly cut in in the self-tapping process and bears corresponding loads in the using process.

Description

Technical Field

[0001] The present invention relates to the technical field of fastener thread design, and particularly to a manufacturing method for self-tapping and self-locking threads for lightweight materials. Background Art

[0002] In recent years, the penetration rate of new energy vehicles has been continuously increasing, and new high-strength and low-density lightweight structural components have been widely used. Therefore, it is particularly important to develop and design self-tapping and self-locking threads for lightweight materials. In traditional thread connection technology, ordinary triangular thread bolts are usually used in conjunction with steel workpieces with prefabricated internal threads. With the rapid development of the new energy vehicle industry, lightweight design has become an industry trend, and high-strength and low-density materials are increasingly widely used in structural components. However, existing thread technologies are difficult to meet the connection requirements of lightweight materials, and the self-tapping and self-locking threads developed currently have some defects, such as: Traditional thread connection requires pre-processing of internal holes and internal threads on lightweight materials, adding multiple processes and significantly increasing the manufacturing cost. Moreover, during the self-tapping and self-extrusion process of ordinary triangular threads, due to the significant differences in the plastic deformation ability and strength between lightweight materials and steel, it is easy to cause material cracking, thread pulling off or loosening, and cannot meet the requirements of long-term stable connection. In addition, traditional threads rely on friction to achieve self-locking, but in an environment of vibration or load change, connection failure is likely to occur due to the attenuation of friction force.

[0003] In view of the above problems, it is urgent to innovate and design on the basis of the original thread manufacturing of lightweight materials. Summary of the Invention

[0004] The purpose of the present invention is to provide a manufacturing method for self-tapping and self-locking threads for lightweight materials, so as to solve the problems mentioned in the above background art that due to the significant differences in the plastic deformation ability and strength between lightweight materials and steel, it is easy to cause material cracking, thread pulling off or loosening, and cannot meet the requirements of long-term stable connection, and traditional threads rely on friction to achieve self-locking, but in an environment of vibration or load change, connection failure is likely to occur due to the attenuation of friction force.

[0005] To achieve the above purpose, the present invention provides the following technical solution: A self-tapping and self-locking thread structure for lightweight materials, including a nut. The nut is a nut made of lightweight material, and the nut is threadedly connected to a bolt. Moreover, the nut is threadedly connected within an aluminum-magnesium alloy plate. The surface of the nut is provided with external threads and internal threads, and the outer wall of the bolt and the inner wall of the aluminum-magnesium alloy plate are provided with the same thread structure. The thread structures of the bolt and the aluminum-magnesium alloy plate are consistent with the thread profile structure of the external threads and the internal threads.

[0006] Adopting the above technical solution enables the nut and bolt made of lightweight materials to have the function of self-tapping and self-locking.

[0007] Preferably, the internal thread of the nut is threadedly connected to the bolt, and the threads of the bolt are manufactured by the same method. A groove is provided at the top end of the bolt, and a limiting block is snap-fitted in the groove.

[0008] With the above technical solution, the internal thread of the nut and the threads of the bolt are manufactured by the same method, ensuring that parameters such as the thread profile and pitch of the two are highly matched, the connection is tight and reliable, and the load transmission capacity is strong.

[0009] Preferably, the external thread of the nut is threadedly connected to the aluminum-magnesium alloy plate, and the threads at the connection of the aluminum-magnesium alloy plate are manufactured by the same method.

[0010] With the above technical solution, the threads at the connection of the external thread of the nut and the aluminum-magnesium alloy plate are manufactured by the same method, simplifying the processing technology of the aluminum-magnesium alloy plate, eliminating the need for pre-processing of the internal thread, and reducing production costs.

[0011] A manufacturing method for a self-tapping and self-locking thread for a lightweight material according to any one of the above, comprising the following steps: Step 1: Select a suitable metal material as the raw material for the self-tapping and self-locking thread according to the type of lightweight material, ensuring that its hardness and toughness meet the requirements; Step 2: Process the material selected in Step 1 into a blank with the required size and shape; Step 3: Construct an initial pattern on the cross-section of the blank where the thread is to be manufactured. Through geometric division, rotation, and translation operations, a preliminary image is obtained. After structural optimization, a self-tapping and self-locking thread is formed on the blank; Step 4: Heat-treat the formed thread to improve its hardness and strength. The heat-treatment process is determined according to the material characteristics; Step 5: Perform surface treatment on the heat-treated thread to improve its corrosion resistance and lubrication performance.

[0012] With the above technical solution, this manufacturing method provides a complete manufacturing process for self-tapping and self-locking threads for lightweight materials through the coordination of multiple steps.

[0013] Preferably, the detailed steps from constructing the initial pattern to structural optimization in Step 3 include: Constructing the initial pattern: Draw an isosceles triangle A with a vertex angle of 60 degrees. At one of its vertices A1, draw an isosceles triangle B with a vertex angle of 30 degrees, such that the two sides BA and BB of triangle B intersect with the base AA of the isosceles triangle A; Performing geometric division: Divide the symmetry center line C of the isosceles triangle A and the isosceles triangle B into 8 equal parts to obtain the 1 / 9, 2 / 9, 3 / 9, 4 / 9, 5 / 9, 6 / 9, 7 / 9, 8 / 9, and 9 / 9 lines; Rotation operation: Using point C1 as the rotation base point, rotate the isosceles triangle B clockwise by 10 degrees. Point C1 is the intersection of the triangle bisector and the 5 / 9 bisector. Translation operation: Using point C2 as the base point, translate the rotated isosceles triangle B to point C3. Point C2 is the intersection of line BA and the 5 / 9 bisector after triangle B is rotated by 10 degrees. Point C3 is the intersection of line AA (a side line of triangle A) and the 5 / 9 bisector. Another translation: Copy and translate side AB of isosceles triangle A with point C4 as the base point to point C5. Point C4 is the intersection of line AB (a side line of triangle A) and the 5 / 9 bisector. Point C5 is the intersection of line BB and the 5 / 9 bisector after triangle B is rotated by 10 degrees. Structure optimization: Trim the side lines to form a specific cross-sectional structure plane. Round the corners at the joints to disperse stress concentration. Remove part of the structure of the isosceles triangle to make the thread profile form a wedge structure.

[0014] Adopting the above technical solution, through detailed graphic construction, geometric transformation and structure optimization steps, the thread profile of the self-tapping and self-locking thread is precisely shaped.

[0015] Preferably, when the thread profile of the wedge structure cooperates with lightweight materials, it can cause the lightweight materials to form a matching internal thread at the pre-drilled holes.

[0016] Adopting the above technical solution, when the thread profile of the wedge structure cooperates with lightweight materials, it can guide the lightweight materials to form a suitable internal thread at the pre-drilled holes, ensuring the tightness of the thread connection, making the two combine firmly, and effectively avoiding loosening and displacement at the connection part.

[0017] Preferably, for the self-tapping and self-locking thread obtained by this forming method, after the installation torque is applied to the predetermined torque, the static loosening torque is higher than the installation torque, achieving self-locking.

[0018] Adopting the above technical solution, during long-term use, even under external forces such as vibration and impact, the thread connection is not easily loosened, improving the stability of the connection.

[0019] Preferably, the radius of the rounded corners is adjusted according to the mechanical properties of the lightweight materials. For lightweight materials with higher hardness and lower plasticity, the rounded radius is appropriately increased, and the range is 0.1 - 0.3 mm.

[0020] Adopting the above technical solution, for lightweight materials with higher hardness and lower plasticity, by adjusting the corresponding radius of the rounded corners and appropriately increasing the rounded radius, the stress can be evenly distributed.

[0021] Preferably, for lightweight materials with lower hardness and better plasticity, the radius of the rounded corners ranges from 0.05 - 0.1 mm.

[0022] By adopting the above technical solution, the corresponding fillet radius is adjusted for lightweight materials with low hardness and good plasticity to prevent excessive deformation of the material due to excessive fillet radius, which may affect the connection strength.

[0023] Preferably, during the trimming process, the dimensional accuracy of the thread profile is strictly controlled, and the dimensional tolerance is controlled within ±0.03 mm to ensure the matching accuracy of the thread and the lightweight material.

[0024] By adopting the above technical solution, the thread and the lightweight material can be precisely matched and evenly stressed, avoiding local stress concentration due to dimensional deviation, thereby improving the stability and reliability of the threaded connection.

[0025] Preferably, the surface treatment in step 5 includes galvanizing and phosphating film, wherein the thickness of the galvanizing layer is controlled to be 5-15 μm, and the thickness of the phosphating film is controlled to be 2-10 μm.

[0026] By adopting the above technical solution, the galvanized layer can form a dense protective film on the surface of the thread, effectively blocking the erosion of external corrosive media. The phosphating film not only further enhances the corrosion resistance, but also has good lubrication properties, reducing the friction when the thread penetrates into lightweight materials and reducing the difficulty of installation.

[0027] Compared with the prior art, the invention has the following beneficial effects: the manufacturing method of the self-tapping and self-locking thread for the lightweight material: 1. When manufacturing the threaded structure, the method selects appropriate metal materials according to the type of lightweight materials to ensure that the hardness and toughness of the raw materials match the lightweight materials. When connecting with aluminum alloy, the selected metal materials can ensure that the manufactured threads can be smoothly cut in during the self-tapping process and can withstand the corresponding load during use, avoiding the problems of looseness and deformation of the connection parts. Then, through subsequent heat treatment, the hardness and strength of the threads are further improved, and their load-bearing capacity is enhanced to meet the use requirements under different working conditions; 2. The wedge-shaped thread profile formed by steps such as constructing the initial graphics, geometric segmentation, rotation and translation, and structural optimization has excellent performance in self-tapping and self-locking. The tip of the wedge-shaped structure is easy to cut into lightweight materials, effectively reducing the tapping torque and improving installation efficiency. When combined with lightweight materials, it can form matching internal threads at the prefabricated holes of lightweight materials to achieve a tight connection. Moreover, after applying a predetermined torque during installation, the static loosening torque of this thread profile is higher than the installation torque, achieving reliable self-locking, effectively improving the stability of the connection, and reducing the risk of loosening caused by factors such as vibration and load changes. 3. During the manufacturing process of this method, through galvanizing and phosphating treatment on the thread surface, the thickness of the galvanized layer is controlled within 5 - 15 μm, and the thickness of the phosphating film is controlled within 2 - 10 μm. Among them, the galvanized layer can form a dense protective film on the thread surface, effectively preventing the thread from being corroded and extending its service life. The phosphating film not only has good lubricating performance, can reduce the friction when the thread penetrates into the light material, reduce the installation difficulty, but also can further enhance the corrosion resistance of the thread and improve the overall connection performance. Brief Description of the Drawings

[0028] Figure 1 It is a schematic structural diagram of the overall installation state of the present invention; Figure 2 It is a three-dimensional structural diagram of the installation of the nut and bolt of the present invention; Figure 3 It is a schematic side-sectional structure diagram of the installation of the nut and bolt of the present invention; Figure 4 It is a three-dimensional structural diagram of the bolt of the present invention; Figure 5 It is a structural diagram of the bolt and the groove of the present invention; Figure 6 It is a schematic sectional structure diagram of the A - A' section of the present invention; Figure 7 It is a three-dimensional structural diagram of the nut of the present invention; Figure 8 It is a structural diagram of the external thread and the internal thread on the nut of the present invention; Figure 9 It is a schematic sectional structure diagram of the b - b' section of the present invention; Figure 10 It is a structural diagram of the installation of the nut and the aluminum - magnesium alloy plate of the present invention; Figure 11 It is a schematic sectional structure diagram of the c - c' section of the present invention; Figure 12 It is a preliminary schematic diagram of the thread tooth profile construction structure of the present invention; Figure 13 It is an adjusted schematic diagram of the thread tooth profile construction structure of the present invention; Figure 14 It is a final schematic diagram of the thread tooth profile construction structure of the present invention; Figure 15 It is a schematic sectional structure diagram of the complete thread tooth profile construction of the present invention.

[0029] In the figure: 1. Nut; 2. External thread; 3. Internal thread; 4. Bolt; 5. Groove; 6. Limiting block; 7. Aluminum - magnesium alloy plate. Detailed Description of the Invention

[0030] The technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings in the embodiments of the present invention. Obviously, the described embodiments are only a part of the embodiments of the present invention, rather than all the embodiments. All other embodiments obtained by those of ordinary skill in the art based on the embodiments of the present invention without creative efforts shall fall within the protection scope of the present invention.

[0031] Please refer to Figures 1-15 , the present invention provides a technical solution: a manufacturing method of a self-tapping and self-locking thread for a lightweight material, including a nut 1, an external thread 2, an internal thread 3, a bolt 4, a groove 5, a limiting block 6, and an aluminum-magnesium alloy plate 7; Among them, the surface of the nut 1 is provided with an external thread 2 and an internal thread 3. The internal thread 3 of the nut 1 is threadedly connected to the bolt 4, and the thread of the bolt 4 is manufactured by the same method. A groove 5 is opened at the top of the bolt 4, and a limiting block 6 is snap-fitted in the groove 5. The external thread 2 of the nut 1 is threadedly connected to the aluminum-magnesium alloy plate 7, and the thread at the connection of the aluminum-magnesium alloy plate 7 is manufactured by the same method. The thread manufacturing method of the external thread 2 and the internal thread 3 includes the following steps: Step 1: Select a suitable metal material as the raw material for the self-tapping and self-locking thread according to the type of the lightweight material to ensure that its hardness and toughness meet the requirements; Step 2: Process the material selected in Step 1 into a blank with the required size and shape; Step 3: Construct an initial graph on the cross-section of the blank where the thread is to be manufactured. After geometric division, rotation, and translation operations, a preliminary image is obtained. After structural optimization, a self-tapping and self-locking thread is formed on the blank, and the dimensional accuracy of the thread profile is strictly controlled, with the dimensional tolerance controlled within ±0.03 mm to ensure the fitting accuracy between the thread and the lightweight material; Step 4: Heat-treat the formed thread to improve its hardness and strength. The heat-treatment process is determined according to the material characteristics. During the process of trimming the edge line; Step 5: Perform surface treatment on the heat-treated thread to improve its corrosion resistance and lubrication performance. The surface treatment includes galvanizing and phosphating film, where the thickness of the galvanized layer is controlled within 5 - 15 μm, and the thickness of the phosphating film is controlled within 2 - 10 μm; Combined with the Figures 1-15 shown in the accompanying drawings of the specification, where the Figures 1-11As shown, it is a structural connection realized by the threads manufactured by this method. Among them, the internal thread 3 of the nut 1 is threadedly connected to the bolt 4, and the threads of the bolt 4 are manufactured by the same method, so as to ensure that the thread profile, pitch and other parameters of the nut and the bolt are completely matched, enabling them to fit tightly when connected and transmit a large load. A limit block 6 is snap-fitted and installed in the groove 5 opened at the top of the bolt 4. In actual use, when the nut 1 and the bolt 4 are tightened, the limit block 6 can prevent the bolt 4 from rotating relative to the nut 1, further enhancing the stability of the connection and preventing the threads from loosening due to factors such as vibration; The external thread 2 of the nut 1 is threadedly connected to the aluminum-magnesium alloy plate 7, and the threads at the connection of the aluminum-magnesium alloy plate 7 are manufactured by the same method. This connection method utilizes the characteristics of self-tapping and self-locking threads. During installation, the external thread 2 of the nut 1 can directly penetrate into the aluminum-magnesium alloy plate 7 without pre-processing the internal thread 3, simplifying the processing technology and reducing costs. At the same time, due to the wedge-shaped structure and self-tapping and self-locking performance of the threads, a reliable connection can be formed on the aluminum-magnesium alloy plate 7, meeting the connection strength and stability requirements in engineering practice; In this thread manufacturing method, lightweight materials are used, and metal materials are selected as raw materials according to the type of lightweight materials because there are differences in mechanical properties such as hardness and plasticity among different lightweight materials. Among them, the hardness of aluminum alloy is relatively low and the plasticity is good. It is necessary to select a matching metal material to ensure that the manufactured threads can not only guarantee sufficient strength to bear the load at the connection part when connected to the aluminum alloy, but also closely fit with the aluminum alloy through its own plastic deformation during the self-tapping process to prevent problems such as loosening and pulling off. Among them, the hardness and toughness of medium carbon steel can form a good match with the aluminum alloy after processing, ensuring that the threads can be smoothly formed when penetrating into the aluminum alloy and at the same time guaranteeing the connection strength and stability; Magnesium alloy has a lower density than aluminum alloy, but its chemical properties are more active and it is prone to corrosion. Considering its characteristics, alloy steel added with appropriate amounts of alloying elements such as chromium and nickel is selected as the raw material. Chromium and nickel can improve the corrosion resistance of the alloy steel, enabling it to effectively avoid connection failure caused by electrochemical corrosion when connected to the magnesium alloy. At the same time, the strength and toughness of the alloy steel can also meet the requirements of self-tapping and self-locking; In the process of billet preparation, according to the size and shape of the required thread, high-precision digital cutting equipment is used to cut the selected metal material into a suitable billet length. For the thread used to connect the aluminum alloy structural parts of the automobile, the billet length accuracy is controlled at ±0.5mm to ensure the accuracy of subsequent processing. Subsequently, the cut billet is preliminarily processed by forging or rolling process to give it a rough shape. Through forging or rolling, the internal structure of the metal material can be improved, and the density and mechanical properties of the material can be improved. In the forging process, the forging temperature is controlled at 800-900℃, and the forging ratio is 3-4, so that the grain of the billet is refined and its strength and toughness are improved. Finally, the billet is further accurately processed by lathes, milling machines and other mechanical processing equipment to ensure that the dimensional accuracy and surface roughness of the billet meet the requirements. The outer diameter size tolerance of the billet is controlled at ±0.05mm, and the surface roughness Ra is controlled at 1.6-3.2μm, providing a good foundation for subsequent thread forming. The detailed steps from the initial graph constructed in step 3 to structural optimization include: Construct the initial figure: draw an isosceles triangle A with a vertex angle of 60 degrees, and draw an isosceles triangle B with a vertex angle of 30 degrees at one of its vertices A1, so that the two sides BA and BB of triangle B intersect with the base AA of isosceles triangle A; Perform geometric division: divide the symmetric center line C of isosceles triangle A and isosceles triangle B into 8 equal parts, and obtain lines 1 / 9, 2 / 9, 3 / 9, 4 / 9, 5 / 9, 6 / 9, 7 / 9, 8 / 9, and 9 / 9; Rotation operation: Take point C1 as the rotation base point and rotate the isosceles triangle B 10 degrees clockwise, where point C1 is the intersection of the triangle bisector and the 5 / 9 bisector; Translation operation: Using point C2 as the base point, translate the rotated isosceles triangle B to point C3, where point C2 is the intersection of line BA and the 5 / 9 bisector after triangle B is rotated 10 degrees, and point C3 is the intersection of line AA of triangle A and the 5 / 9 bisector; Translate again: copy and translate one side AB of isosceles triangle A to point C5 with point C4 as the base point, where point C4 is the intersection of side AB of triangle A and the 5 / 9 bisector, and point C5 is the intersection of line BB and the 5 / 9 bisector after triangle B is rotated 10 degrees; Structural optimization: trim the edges to form a specific cross-sectional structural plane, fillet the joints to disperse stress concentration, remove the isosceles triangle part of the structure, and make the thread profile form a wedge-shaped structure. The thread profile of the wedge-shaped structure, when combined with lightweight materials, can enable the lightweight material to form a matching internal thread at the prefabricated hole.

[0032] The self-tapping and self-locking thread obtained by this forming method has a static loosening torque higher than the installation torque after the installation is applied to the predetermined torque, achieving self-locking.

[0033] The radius of the rounded corner is adjusted according to the mechanical properties of the lightweight material. For lightweight materials with higher hardness and poorer plasticity, the rounded radius is appropriately increased, ranging from 0.1 to 0.3 mm. For lightweight materials with lower hardness and better plasticity, the rounded radius ranges from 0.05 to 0.1 mm. Combined with the attached drawings of the specification Figures 12-15 As shown, a high-precision cold heading die is designed and manufactured according to the above thread profile. Among them, the die material is selected from high-quality die steels such as Cr12MoV, and its hardness can reach HRC58 - 62. The die angle of the concave die is designed to be 65° - 70° to ensure that the blank can be successfully formed into the required thread profile during cold heading. The surface roughness Ra of the cold heading die is controlled within 0.2 - 0.4 μm to reduce the friction between the blank and the die and ensure the surface quality of the thread. Put the blank into the cold heading machine, and the blank is successively extruded and formed through the multi-station die of the cold heading machine to form a self-tapping and self-locking thread. The working frequency of the cold heading machine is adjusted according to the thread size and material characteristics, generally 20 - 50 times per minute. During the processing, molybdenum disulfide lubricant is used to lubricate the die and the blank, and the lubricant film thickness is controlled within 3 - 5 μm to further reduce the friction and improve the forming quality of the thread and the die life. For the thread made of medium carbon steel, the quenching temperature is set at 820 - 840 °C, and the holding time is determined according to the size and shape of the thread, generally 30 - 60 minutes. Among them, the quenching medium can be selected as quenching oil, and the cooling rate of the quenching oil is moderate, which can effectively avoid cracks in the thread during quenching. For the thread made of alloy steel, the quenching temperature is adjusted according to the types and contents of alloying elements. For example, for alloy steel containing more chromium and nickel elements, the quenching temperature can be controlled at 860 - 920 °C. Subsequently, the quenched thread is subjected to tempering treatment. The tempering temperature is selected according to the required hardness and strength. For medium carbon steel, the tempering temperature is usually between 450 - 550 °C, and the tempering time is 60 - 90 minutes, which can enable the thread to obtain good comprehensive mechanical properties. For alloy steel, the tempering temperature may need to be higher, at 550 - 650 °C, and the tempering time is the same, to give full play to the role of alloying elements and improve the hardness, strength and toughness of the thread. Finally, the thread surface is treated, and the heat-treated thread is galvanized using a hot-dip galvanizing process. The thread is immersed in a zinc liquid at a temperature of 450-480°C. The galvanizing time is controlled according to the required galvanized layer thickness, generally 10-20 minutes, to ensure that the galvanized layer thickness is between 5-15μm. A dense zinc layer is formed on the thread surface after hot-dip galvanizing, which can effectively prevent the thread from rusting and improve its corrosion resistance. After galvanizing, the thread is phosphating, and the phosphating liquid uses a zinc-based phosphating liquid. The phosphating temperature is controlled at 30-50°C, and the phosphating time is 15-30 minutes, so that the phosphating film thickness reaches 2-10μm. The phosphating film can not only further enhance the corrosion resistance of the thread, but also has good lubrication properties, reducing the friction of the thread when it penetrates lightweight materials. At this point, the thread manufacturing is completed and finally tested; Use calipers, micrometers, thread gauges and other measuring tools to test various dimensions of the thread, such as pitch, thread height, outer diameter, inner diameter, etc., to ensure that the dimensional tolerance of the thread meets the specified ±0.03mm. If the dimensional deviation exceeds the range, adjust the processing equipment or rework the product; Then use the torque tester to drive the threaded specimen into the corresponding lightweight material specimen, and record the torque changes during the driving process to ensure that the driving torque is within a reasonable range. If the driving torque is too large or too small, analyze the cause and optimize the thread profile or manufacturing process. After the threaded specimen is driven into the lightweight material specimen and reaches the predetermined torque, use the torque tester to measure the static loosening torque to ensure that the static loosening torque is higher than the installation torque to achieve a reliable self-locking function. If the static loosening torque does not meet the requirements, adjust the thread profile structure, heat treatment process or surface treatment process.

[0034] While the embodiments of the present invention have been shown and described, it will be appreciated by those skilled in the art that many changes, modifications, substitutions and variations can be made to the embodiments without departing from the principles and spirit of the invention.

Claims

1. A self-tapping and self-locking thread structure for lightweight materials, comprising a nut (1), wherein the nut (1) is a nut made of lightweight material, and the nut (1) is threadedly connected to a bolt (4), and the nut (1) is threadedly connected in an aluminum-magnesium alloy plate (7), characterized in that: The surface of the nut (1) is provided with an external thread (2) and an internal thread (3), and the outer wall of the bolt (4) and the inner wall of the aluminum-magnesium alloy plate (7) are provided with the same thread structure, and the thread structure of the bolt (4) and the aluminum-magnesium alloy plate (7) is consistent with the thread tooth structure of the external thread (2) and the internal thread (3).

2. A self-tapping and self-locking thread structure for lightweight materials according to claim 1, characterized in that: The internal thread (3) of the nut (1) is threadedly connected to the bolt (4), and the thread of the bolt (4) is manufactured using the same method. A groove (5) is provided at the top end of the bolt (4), and a limit block (6) is mounted in the groove (5).

3. A self-tapping and self-locking thread structure for lightweight materials according to claim 1, characterized in that: The external thread (2) of the nut (1) is threadedly connected to the aluminum-magnesium alloy plate (7), and the threads at the connection of the aluminum-magnesium alloy plate (7) are manufactured using the same method.

4. A method for manufacturing a self-tapping and self-locking thread for a lightweight material according to any one of claims 1 to 3, characterized in that: The following steps are involved: Step 1: Select appropriate metal material as the raw material for self-tapping and self-locking threads according to the type of lightweight material, and ensure that its hardness and toughness meet the requirements; Step 2: Process the material selected in step 1 to produce blanks of required size and shape; Step 3: Construct an initial graphic on the cross section of the blank where the thread is to be manufactured, obtain a preliminary image through geometric segmentation, rotation and translation operations, and then form a self-tapping and self-locking thread on the blank after structural optimization; Step 4: Heat treat the formed threads to improve their hardness and strength. The heat treatment process is determined according to the material properties. Step 5: Surface treatment is performed on the heat-treated threads to improve their corrosion resistance and lubricity.

5. The method for manufacturing a self-tapping and self-locking thread for a lightweight material according to claim 4, characterized in that: The detailed steps from the initial graph constructed in step 3 to structural optimization include: Construct the initial figure: draw an isosceles triangle A with a vertex angle of 60 degrees, and draw an isosceles triangle B with a vertex angle of 30 degrees at one of its vertices A1, so that the two sides BA and BB of triangle B intersect with the base AA of isosceles triangle A; Perform geometric division: divide the symmetric center line C of isosceles triangle A and isosceles triangle B into 8 equal parts, and obtain lines 1 / 9, 2 / 9, 3 / 9, 4 / 9, 5 / 9, 6 / 9, 7 / 9, 8 / 9, and 9 / 9; Rotation operation: Take point C1 as the rotation base point and rotate the isosceles triangle B 10 degrees clockwise, where point C1 is the intersection of the triangle bisector and the 5 / 9 bisector; Translation operation: Using point C2 as the base point, translate the rotated isosceles triangle B to point C3, where point C2 is the intersection of line BA and the 5 / 9 bisector after triangle B is rotated 10 degrees, and point C3 is the intersection of line AA of triangle A and the 5 / 9 bisector; Translate again: copy and translate one side AB of isosceles triangle A to point C5 with point C4 as the base point, where point C4 is the intersection of side AB of triangle A and the 5 / 9 bisector, and point C5 is the intersection of line BB and the 5 / 9 bisector after triangle B is rotated 10 degrees; Structural optimization: trim the edges to form a specific cross-sectional structural plane, fillet the joints to disperse stress concentration, remove the isosceles triangle part of the structure, and make the thread profile form a wedge-shaped structure.

6. The method for manufacturing a self-tapping and self-locking thread for a lightweight material according to claim 5, characterized in that: When the thread profile of the wedge-shaped structure is matched with a lightweight material, the lightweight material can form an internal thread matching the lightweight material at the prefabricated hole.

7. The method for manufacturing a self-tapping and self-locking thread for a lightweight material according to claim 5, characterized in that: The self-tapping and self-locking thread obtained by the forming method has a static loosening torque higher than the installation torque after a predetermined torque is applied during installation, thereby achieving self-locking.

8. The method for manufacturing a self-tapping and self-locking thread for a lightweight material according to claim 5, characterized in that: The radius of the fillet is adjusted according to the mechanical properties of the lightweight material. For lightweight materials with high hardness and poor plasticity, the fillet radius is appropriately increased within a range of 0.1-0.3 mm.

9. The method for manufacturing a self-tapping and self-locking thread for a lightweight material according to claim 5, characterized in that: For lightweight materials with lower hardness and better plasticity, the radius of the fillet is in the range of 0.05-0.1 mm.

10. The method for manufacturing a self-tapping and self-locking thread for a lightweight material according to claim 5, characterized in that: During the trimming process, the dimensional accuracy of the thread profile is strictly controlled, and the dimensional tolerance is controlled within ±0.03mm to ensure the matching accuracy of the thread and the lightweight material.

11. The method for manufacturing a self-tapping and self-locking thread for a lightweight material according to claim 4, characterized in that: The surface treatment in step 5 includes galvanizing and phosphating film, wherein the thickness of the galvanizing layer is controlled at 5-15 μm, and the thickness of the phosphating film is controlled at 2-10 μm.

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